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FIELD OF THE INVENTION
[0001] The invention relates to a seat belt webbing and a method for manufacturing the same for a motor vehicle restraint system.
BACKGROUND OF THE INVENTION
[0002] Seat belts are used for example in motor vehicles, aircrafts and other mobile devices for restraining the occupant. To perform their function, the seat belts need to have a predetermined tensile strength. Furthermore, the seat belts should generally comprise a surface having as low friction as possible and a soft edge, in order that the occupant is obstructed by the seat belt as little as possible and the clothes of the occupant are not damaged.
[0003] The seat belt webbing comprises a plurality of warp threads running in the longitudinal direction which are connected with each other by a weft thread running transversely to the warp threads. During the weaving process, the weft thread is shot through the warp threads from one side of the belt webbing using a weft needle and is caught on the other side using a catch thread, so that when the weft needle is retracted the weft thread is not retracted with it. In the case of loading the seat belt webbing during an accident the warp threads are the load-bearing threads and therefore need to have a certain tensile strength, whereas the weft thread is loaded to a lesser extent and essentially forms the surface of the belt webbing. Thus, the weft thread should have better surface properties than the warp threads, however, in the sense of a softer surface may have a lower tensile strength than the warp threads.
[0004] From EP 1 514 962 A2, a belt webbing is known, which in the edge regions comprises warp threads having a different shrinkage characteristic than the warp threads in the central region. In the successive shoots, the weft thread is inter-woven with a varying number of warp threads, so that in the edge region certain warp threads, for example at every fourth or fifth shoot only, are looped around by the weft thread. After weaving the belt webbing it is subjected to a heat treatment, during which a soft edge is formed by intentionally shrinking the warp threads differently in the edge region.
[0005] Furthermore, seat belt webbings are known, in which the warp threads in the edge region are designed to be considerably finer than the warp threads in the central region. Owing to the finer warp threads in the edge region, the edge of the seat belt webbing is softer and the surface of the seat belt webbing is considerably more homogeneous, so that the sawing effect of the seat belt webbing when rubbing against the edge is considerably reduced.
[0006] It is the object of the invention to provide an enhanced seat belt webbing comprising a soft edge and a method for manufacturing the same.
SUMMARY OF THE INVENTION
[0007] For the solution of the object, it is proposed according to the invention that the catch thread is placed between the warp threads and is covered by the weft thread and/or the warp threads towards the surface of the seat belt webbing.
[0008] The catch thread itself in the seat belt webbing has the function to retain the weft thread in the reversal points during the weaving process, which is why it has to have a certain tensile strength, in order that it does not tear during the weaving process and consequently the weaving process needs to be interrupted. Surprisingly, the catch thread appearing on the surface has turned out to have a crucial co-influence on the hardness of the edge. Due to its function, the properties of the catch thread differ from the properties of the weft thread, so that owing to the catch thread appearing on the surface between the weft threads the surface becomes inhomogeneous, and the sawing effect of the edge when rubbing for example against the clothes of the occupant is increased. Due to the solution according to the invention the surface of the edge is now defined by the weft thread and/or by the warp threads only, as the catch thread is placed between the warp threads and is covered by the weft threads and/or the warp threads. The catch thread thus is no longer visible from the outside. A further advantage resulting from the invention is that both edges of the seat belt webbing thus are nearly identical, even if a weaving technique is used, in which a catch thread is provided on one side only, and the weft thread is inserted from one side only.
[0009] It generally is a disadvantage of inhomogeneous sides of the seat belt webbing that they wear away differently, and the seat belt webbing thus, after long-time wearing, gives the optical impression to the beholder of being of lower value. Furthermore, when the belt webbing is mounted with a misalignment the inhomogeneous edges may lead to an undesired noise occurring in the seat belt retractor during the retraction movement and extraction movement of the seat belt webbing. For this reason, when mounting the belt webbing in the seat belt retractor specific cost-incurring measures need to be taken, in order to prevent the seat belt webbing from being mounted incorrectly with a misalignment. Inhomogeneous edges further result in the seat belt webbing making additional noise when being pulled through the deflector, in the retraction forces and extraction forces of the seat belt webbing changing disadvantageously and in the belt bearing surface of the deflector being worn away unequally.
DESCRIPTION OF THE DRAWING
[0010] In the following, the invention is described in more detail on the basis of a preferred embodiment.
[0011] FIG. 1 shows a seat belt webbing according to the invention comprising a catch thread which is placed between the warp threads.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The seat belt webbing may be subdivided into a center portion A and an edge portion B. In the center portion A, warp threads 1 are provided, which have a thread size of 900 to 2100 dtex and are designed as multifilaments comprising filaments which are not twisted or filaments which are twisted with up to 150 twists per meter length. The warp threads 1 have the function to absorb the tensile forces acting during the accident and, therefore, are particularly strong and thus also relatively stiff. In the edge portion B, finer warp threads 3 having a thread size of 400 to 1100 dtex are provided, which as well are designed as multifilaments comprising for example 28 filaments. The filaments further are twisted with each other up to 150 times per meter length.
[0013] Furthermore, a weft thread 2 is provided, which, while the belt webbing is woven, with a weft needle is shot from one side through a shed formed by two layers of warp threads 1 and 3 which are aligned at an angle relative to each other. At an edge of the seat belt webbing, the weft thread 2 is caught using a catch thread 5 and is crocheted with the same via a knitting needle. The weft thread 2 as well is designed as a multifilament having a thread size of 280 to 1100 dtex and comprises for example 96 filaments which are twisted with each other 130 times per meter length. Owing to the great number of filaments the weft thread 2 is particularly self-moveable, so that with the weft thread a particularly soft and homogeneous surface can be obtained. The catch thread 5 is designed as a multifilament as well and has a thread size of 280 dtex and comprises 48 filaments with 80 twists per meter. Furthermore, a lock thread 4 is provided, which is guided together with the catch thread 5 and provides a better coherence of the textile composite in the seat belt webbing.
[0014] As can be seen in FIG. 1 , the finer warp threads 3 of the edge portion B are interwoven with the weft thread 2 to form two layers 6 and 7 each with the weaving pattern being formed in such a way that, on one side, three warp threads 3 in a package III and, on the other side, one warp thread 3 in a package I are alternately passed by the weft thread 2 . The weft thread 2 is a single thread which during the weaving process is guided in a periodic to-and-fro motion and thereby effects the cross connection of the warp threads 1 and 3 and further forms at least a major part of the surface of the seat belt webbing.
[0015] At every second shoot, the weft thread 2 is only guided past the warp threads 3 and subsequently, when moving backwards, pulls the catch thread 5 to such an extent into the edge portion B that, in the finish-woven seat belt webbing, the same gets to rest between the warp threads 3 and is covered by the weft thread 2 towards the surface. The catch thread 5 preferably is only pulled into the edge portion B maximally up to the edge of the center portion A between the finer warp threads 3 , as the weave of the warp threads 1 to the weft thread 2 in the center portion A differs from the weave of the finer warp threads 3 to the weft thread 2 in the edge portion B. After said shoot of the weft thread 2 , the weft thread 2 at the next shoot is shot through at least a partial number of the warp threads 3 , preferably through one of the layers 6 or 7 , is then caught by the catch thread 5 and, while moving backwards, pulls the catch thread 5 as well as some of the warp threads 3 up to the center portion A. Thus, at the edge of the center portion A an overall soft edge with an inside catch thread 5 is generated, the exterior surface of which edge is formed by the weft thread 2 and the finer warp threads 3 only. As a result, an identical surface structure of the edges of the seat belt webbing is generated, even if the weft thread 2 is caught by the catch thread 5 on one side only, as the catch thread 5 is placed between the finer warp threads 3 and, towards the surface, is covered all over by the weft thread 2 , and thus does not appear on the surface.
[0016] In particular, the tensile load in the catch thread 5 should be chosen in such a way that the weft needle can pull back the catch thread 5 together with the weft thread 2 with the retraction or carry-along movement being automatically restrictable by the varying weave of the warp threads 1 and 3 . The weave of the warp threads 1 and 3 is the weaving pattern formed by the weft thread 2 which is shot through and the warp threads 1 and 3 which are moved thereby individually or together in groups. The weaving pattern in the present seat belt webbing in the center portion A is formed by two paired warp threads 1 each, which are alternately passed by the weft thread 2 on different sides. The weaving pattern and thus the weave of the warp threads 3 in the edge portion B is formed by the alternating groups I and III which are formed from three warp threads 3 or one single warp thread 3 each and are passed by the weft thread 2 on different sides. The movement of the warp threads 1 and 3 between each single shoot of the weft thread 2 here is not described in detail. However, knowing the commonly used weaving technique, the same can easily be deduced.
[0017] The proposed weave of the warp threads 3 in the edge portion B has turned out to be advantageous insofar as an edge can be obtained thereby having a thickness which is essentially identical to the thickness of the seat belt webbing in the center portion A.
[0018] The proposed seat belt webbing in particular provides the advantage that it comprises at least two nearly identical soft edges and, though, can be woven with one weft thread 2 only and a one-side guided catch thread 5 . Thereby, considerably higher working speeds can be obtained than is possible with belt webbings comprising soft edges according to the prior art. The loom can be operated with approx. 1500-1600 U/min resulting in the manufacturing costs of the seat belt webbing being significantly lower than for comparable seat belt webbings comprising soft edges.
[0019] A further advantage resulting from the invention is that the catch thread 5 is no longer allocated to a certain group of warp threads 1 or 3 , as is the case in the prior art. The catch thread 5 loses its orientation and is intentionally placed between the warp threads 1 and 3 without a predetermined orientation, so that the seat belt webbing in the area of the edge no longer shows a hardness distribution which is defined by the catch thread 5 appearing on the surface of the seat belt webbing.
[0020] While the above description constitutes the preferred embodiment of the present invention, it will be appreciated that the invention is susceptible to modification, variation, and change without departing from the proper scope and fair meaning of the accompanying claims.
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The invention relates to a seat belt webbing having a plurality of warp threads ( 1, 3 ), a weft thread ( 2 ) which runs from one edge of the seat belt webbing to the other edge, periodically reversing the direction in reversal points and is interwoven with the warp threads ( 1, 3 ). The weft thread ( 2 ) in the reversal points in an edge portion (B) is folded back forming a loop, and a catch thread ( 5 ) which is fed through the loops of the weft thread ( 2 ). The catch thread ( 5 ) is placed between the warp threads ( 1, 3 ) and is covered by the weft thread ( 2 ) and/or by the warp threads (1, 3) towards the surface of the seat belt webbing.
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CROSS-REFERENCE TO PRIOR APPLICATIONS
This application is the U.S. National Phase application under 35 U.S.C. §371 of International Application Serial No. PCT/IB2012/050879, filed on Feb. 27, 2012, which claims the benefit of European Application Serial No. 11156858.0, filed on Mar. 3, 2011. These applications are hereby incorporated by reference herein.
FIELD OF THE INVENTION
The invention relates to the field of oxygen generation. The invention particularly relates to the field of oxygen separation using pressure swing adsorption combined with a dense inorganic membrane.
BACKGROUND OF THE INVENTION
Oxygen therapy is the administration of oxygen as a therapeutic modality. It is widely used for a variety of purposes in both chronic and acute patient care as it is essential for cell metabolism, and in turn, tissue oxygenation is essential for all physiological functions. Oxygen therapy can be used to benefit the patient by increasing the supply of oxygen to the lungs and thereby increasing the availability of oxygen to the body tissues, especially when the patient is suffering from hypoxia and/or hypoxaemia. Oxygen therapy may be used both in applications in hospital or in home care. The main home care application of oxygen therapy is for patients having severe chronic obstructive pulmonary disease (COPD).
Oxygen may be administered in a number of ways. A preferable way of oxygen administration is given by a so called on demand generation of oxygen, or an in situ generation, respectively. Referring to this, commercial solutions, so-called oxygen concentrators, or separators, respectively, are widely known. These oxygen concentrators mostly separate oxygen from an oxygen comprising gas, so that the oxygen is provided on demand, i.e. directly before use. Most known oxygen concentrators require a compressor to compress the oxygen containing gas. Furthermore, oxygen, preferably pure oxygen, has to be generated. Therefore, most known oxygen concentrators comprise a membrane, in particular an organic membrane, a molecular sieve, or the like, to separate oxygen from the oxygen comprising gas. Alternatively, using a pressure swing adsorption, or vacuum swing adsorption is known.
One of the major drawbacks of the known oxygen concentrators is given by the costs which are generated with respect to producing and operating said devices. Additionally, by using swing processes such as pressure swing adsorption, the generated oxygen typically has a concentration of more than 88% but mostly below 95%, in particular of more than 90% but below 93%. These concentrations, however, might be too low for a plurality of applications.
Known from EP 2 196 235 A1 is a ceramic oxygen generating system for generating and delivering oxygen to a user. This system comprises an electrochemical oxygen generating means for producing a controlled amount and pressure of a desired product gas and an electronically controlled unit controlling the operation of the electrochemical oxygen generating system. The product gas from the gas generating system is thereby communicated to a regulator means for controlling the product flow to a user of the product gas. In order to generate oxygen, the system may comprise a low pressure subsystem which uses ceramic oxygen generating elements for purifying impure oxygen supplied by other oxygen generating techniques, such as pressure swing adsorption.
Using such a system for generating oxygen from an oxygen comprising gas, oxygen of a high purity may be provided. However, by using two oxygen separation devices, the maintenance costs by using the system may be rather high.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method and an arrangement for generating oxygen which overcomes at least one of the limitations as set forth above.
It is a further object of the invention to provide a method and an arrangement for generating oxygen which may provide oxygen with high purity and low maintenance costs.
These objects are achieved by a method of generating oxygen, said method comprising the steps of: intermittently guiding a stream of oxygen comprising gas through at least one adsorption chamber being equipped with an oxygen separation adsorbent, thereby defining an adsorption mode and a desorption mode of the at least one adsorption chamber, and thereby enriching the oxygen comprising gas with respect to oxygen, guiding the enriched oxygen comprising gas to a primary side of a dense membrane, heating the dense membrane to a temperature at which it is permeable for oxygen, generating an oxygen flow through the dense membrane to its secondary side, thereby separating the oxygen from the enriched oxygen comprising gas and forming a stream of oxygen, wherein said method further comprises the step of guiding at least a part of the generated oxygen through the at least one adsorption chamber being in desorption mode.
According to the invention, oxygen is generated by using a method essentially comprising two main steps. The first step comprises an enrichment with respect to oxygen of the oxygen comprising gas resulting in a stream of enriched oxygen comprising gas. This step is carried out by adsorbing the remaining components, or at least a part of the remaining components, of the oxygen comprising gas by an oxygen separation adsorbent. An oxygen separation adsorbent according to the invention is thus an adsorbent letting oxygen pass but interacting with other components, or at least with one other component of the oxygen comprising gas. For example, if the oxygen comprising gas is air, the adsorbent preferably adsorbs nitrogen. The oxygen separation adsorbent is thereby arranged in an adsorbent chamber. This first step provides a flow of gas being enriched with respect to oxygen and thus being pre-purified.
In the second step, the enriched oxygen comprising gas is guided to a membrane unit having a dense membrane, in detail to the primary side of the membrane. This enables to generate a stream of the enriched oxygen comprising gas through the dense membrane, or of the oxygen of the latter, thereby separating the oxygen from the remaining components of enriched the oxygen comprising gas. Especially by using a dense ceramic membrane, the enriched oxygen comprising gas is further purified and thus a flow of pure or essentially pure oxygen is generated as permeate, at the secondary side of the dense membrane. Accordingly, a gas being depleted with respect to oxygen is generated as retentate flow at the primary side of the dense membrane. Referring to this, the primary side of the dense membrane is the side being directed towards the adsorption chamber, i.e. to the side from where the enriched oxygen comprising gas is guided to the membrane. Consequently, the secondary side of the dense membrane is the side being opposite to the primary side, i.e. at the secondary side, pure oxygen is provided.
Furthermore, due to the fact that the oxygen comprising gas is guided through the adsorption chamber intermittently, an adsorption mode and a desorption mode of the at least one adsorption chamber is defined. In detail, in case the oxygen comprising gas is guided through the adsorption chamber, the latter is in adsorption mode, thus adsorbing at least a part of remaining constituents of the oxygen comprising gas. After a certain interval of adsorption, i.e. in which interval the adsorbent chamber is in adsorption mode, the adsorbent has to be regenerated. This means that the adsorbed components have to be desorbed again, for example by flushing the adsorbent with oxygen. During this period of time, the adsorption chamber is in desorption mode, which means that the adsorbed species, for example nitrogen, are at least partially released and flushed out of the chamber by suited measures.
According to the invention, the adsorbent is regenerated in its desorption mode by using at least a part of the permeate stream of the membrane unit, i.e. the generated pure oxygen. Therefore, at least a part of the generated oxygen is guided through the at least one adsorption chamber when the latter is in desorption mode.
These measures according to the invention lead to several benefits. For example, by combining an enrichment of an oxygen comprising gas with respect to oxygen together with the usage of a dense membrane, oxygen may be generated in a very high purity. However due to the fact that the oxygen is pre purified by the oxygen separation adsorbent leading to a high oxygen concentration before reaching the dense membrane, the separation performance of the dense membrane may be improved compared to a single membrane system. In detail, the heating power required for heating the dense membrane in order to make it permeable for oxygen may be considerably reduced. This is especially preferred for homecare devices with respect to therapeutic applications due to the fact that bulky and heavy batteries may be saved. Additionally, the costs of performing the method according to the invention may be reduced increasing the economy of a method according to the present invention.
For example, by using a standard adsorption system as used in nowadays oxygen concentrators for medical applications, approximately 300 W input power may be used to come up with an oxygen flux of 51/min. A main reason for the power consumption is the power consumption of the compressor generating an appropriate gas stream. In a combined adsorption and separating method according to the invention an input power of approximately 130 W may be sufficient for the adsorption chamber. Together with the power input for heating the dense membrane, an overall power input of approximately 240 W may be sufficient.
Additionally, due to the fact that at least a part of the generated oxygen is guided through the at least one adsorption chamber being in desorption mode, oxygen is not guided solely to its desired application, but at least a part of the oxygen stream may be branched off in order to regenerate the adsorbent. This allows optimizing the desorption step. In detail, the desorption step is strongly dependent from the purity of the purging gas. According to the invention, this requirement is solved by the synergistic effect of combining both purifying steps. At the secondary side of the dense membrane, a stream of oxygen is generated having a very high purity, i.e. up to 100%. Therefore, the so generated gas is very well suited for being used as purging gas in order to purge the adsorption chamber to desorb the components being adsorbed to the oxygen separation adsorbent. Thus, according to the invention a very effective desorption may be realized, thereby allowing very short desorption times. This further improves the efficiency of the method according to the invention. Additionally, due to the fact that the generated gas is used for purging purposes, no further gas source has to be provided. Consequently, the method according to the invention may be performed in a very compact device which is particularly suitable for home care applications allowing a high degree of convenience, or for further applications in which only a limited space is available.
Besides, due to the fact that the purging gas is generated at the hot dense membrane, the purging gas as such exhibits elevated temperatures when streaming into the adsorption chamber. This additionally improves the desorption step due to the fact that a desorption is thermodynamically improved by using a hot purging gas. This effect further reduces the time required for a desorption and furthermore improves the efficiency of the desorption.
According to a preferred embodiment of the present invention the stream of oxygen comprises oxygen in a concentration in a range of ≧95%. Consequently, a membrane unit, or a membrane, respectively, is used allowing providing a stream of oxygen in a very high purity, i.e. up to 100%. This further improves the effects of purging the adsorbent chambers with the oxygen stream coming from the membrane chamber.
According to a further preferred embodiment of the present invention the stream of oxygen comprising gas is guided alternately through at least two adsorption chambers being connected in parallel. Again, the generated oxygen is at least partly guided through the respective adsorption chamber when being in desorption mode. This allows generating a continuous, or at least particularly continuous flow of gas being enriched with oxygen at the outlet of the desorption chambers. In detail, a first desorption chamber may be in adsorption mode, i.e. the oxygen comprising gas is guided through this adsorption chamber thereby enriching the oxygen comprising gas with respect to oxygen, whereas the a second adsorption chamber is in desorption mode, i.e. the adsorbent of the latter is regenerated. Accordingly, there is always at least one adsorbent chamber being in adsorption mode, at which time at least one further adsorption chamber is in desorption mode resulting in a continuous stream of enriched oxygen comprising gas. It is clear for one skilled in the art that this embodiment may be performed either with two or more that two adsorption chambers. It may then be adjusted according to the used adsorbent and according to the desired application how many adsorption chambers may be in adsorption mode, or desorption mode, respectively.
According to a further preferred embodiment of the present invention the oxygen is guided through the at least one adsorption chamber being in desorption mode in a direction being reversed with respect to the direction of the stream of oxygen comprising gas. This allows purging the respective adsorption chamber from its outlet side. According to this, the desorption process starts at the downstream end of the adsorption chamber. Therefore, the hot purging gas firstly comes in contact with the downstream end of the adsorption chamber and cools down during flowing through the adsorption chamber. Consequently, the gas is cooler at the upstream end of the adsorption chamber with respect to the flow direction of the oxygen comprising gas resulting in a temperature gradient of the adsorbent from its downstream end to its upstream end at the end of the desorption process. The following adsorption step may thus start using at an adsorbent having only slightly elevated temperatures thus not considerably decreasing the adsorption capability of the adsorbent. Additionally, during the adsorption process, an adsorption front is propagating through the adsorption chamber during which the adsorbent is cooled by means of the oxygen comprising gas. Therefore, when the adsorption front reaches a certain region, the latter does not exhibit elevated temperatures anymore. Consequently, the desorption step may be improved by use of the hot purging gas, whereas the adsorption step is not considerably deteriorated.
According to a further preferred embodiment of the present invention the oxygen comprising gas is guided to the at least one adsorption chamber by use of an overpressure. This method is thus a so called pressure swing adsorption (PSA) process. Pressure swing adsorption processes may enrich the oxygen comprising gas with respect to oxygen in an adaptable concentration. Additionally, pressure swing adsorption is an economic method especially for small scale generation of oxygen having a reasonable purity being suitable for pre-purifying the oxygen comprising gas before the latter reaches the membrane unit.
With this regard, it is especially preferred that an overpressure of ≧0.2 bar to ≦2 bar is used. By using an overpressure in the above identified range, the pressure is sufficient for guiding the oxygen comprising gas through the adsorbent chamber, or the adsorbent chambers, respectively, and furthermore for creating a stream of oxygen enriched gas which may permeate through the dense membrane, or only the oxygen of the latter, respectively. Accordingly, only one pressurizing device may be sufficient for enabling a stream of oxygen comprising gas resulting in a sufficient stream of pure oxygen.
In a further preferred embodiment of the present invention, the oxygen comprising gas is enriched with respect to oxygen in the adsorption chamber to an oxygen concentration in the range of ≦88%. Consequently, the purification of the first step is not required to be in such a high degree being typical for swing adsorption steps, but the purification performance, or enrichment performance, respectively may be downscaled. This allows further reducing the power consumption of the adsorption step such as a lower compressor power. Apart from that, the ratio of the adsorption step with respect to the desorption step may be improved such that adsorption may be performed during a longer time scale before a desorption has to be performed. Additionally, the adsorbent chamber may be downscaled with respect to its dimension by using smaller adsorbent surfaces or smaller adsorption beds. Furthermore, particularly according to this embodiment two adsorption chambers may be sufficient. Consequently, the device for performing the method according to the invention may be very compact. The above defined advantages with respect to lower power consumption and smaller dimensions are especially preferred at home care devices for example in the field of therapeutic applications. The reduced purifying quantity is however not problematic due to the fact that the enriched oxygen comprising gas is purified further by means of the second step, i.e. by the dense membrane.
The present invention further relates to an arrangement for generating oxygen, the arrangement comprising at least one adsorption chamber being equipped with an oxygen separation adsorbent and having an inlet for inserting oxygen comprising gas into the adsorption chamber and an outlet for guiding enriched oxygen comprising gas out of the adsorption chamber, wherein the arrangement further comprises a membrane unit comprising a dense membrane and having an inlet at a primary side of the membrane for inserting enriched oxygen comprising gas into the membrane unit, and an outlet at a secondary side of the membrane for guiding oxygen out of the membrane unit, wherein the outlet of the at least one adsorption chamber is in fluid communication with the inlet of the membrane unit, and wherein a conduit is provided connecting the outlet of the membrane unit with the outlet of the at least one adsorption chamber.
The arrangement according to the invention is configured for performing the method according to the invention. Consequently, essentially the advantages being described with respect to the method according to the invention are achieved. In detail, the arrangement according to the invention allows generating oxygen in a very high purity, thereby being energy saving and thus cost saving. Consequently, the arrangement according to the invention allows enriching an oxygen comprising gas with respect to oxygen in a first step and to separate the oxygen from the enriched oxygen comprising gas in a second step, thereby using the permeate stream of the membrane unit to flush the adsorption chamber, like described above with respect to the method according to the invention.
According to the invention, at least one adsorption chamber is provided. The adsorption chamber is equipped with an oxygen separation adsorbent. According to the invention, an oxygen separation adsorbent shall mean an adsorbent which is capable of at least partly separating oxygen from an oxygen comprising gas. Consequently, the oxygen separation adsorbent is capable of adsorbing substances which are present in the oxygen comprising gas and to let the oxygen pass in order to separate the oxygen from at least a part of the remaining components. In case air is used as oxygen comprising gas, for example, it is preferred that the oxygen separation adsorbent adsorbs nitrogen.
Furthermore, the arrangement according to the invention comprises a dense membrane in order to separate oxygen form the enriched oxygen comprising gas. A dense membrane particularly is a membrane being selectively permeable with respect to oxygen, but being strictly or at least substantially non-permeable for other gases, especially for nitrogen.
Due to the fact that a conduit is provided connecting the outlet of the membrane unit with the outlet of the at least one adsorption chamber, the adsorption chamber may be purged with pure and hot oxygen. A conduit may thereby comprise several single conduits being connected to each other. The conduit thereby particularly extends outside the membrane unit, i.e. the gas is not guided through the membrane in order to guide the oxygen, or at least a part of it, through an adsorption chamber when oxygen comprising gas is guided through the membrane. A conduit may thereby be any device or connection which is capable of transporting a gas stream. For example, the conduit may be a duct, a tube, a pipe, or the like.
In a preferred embodiment of the present invention, the arrangement comprises at least two adsorption chambers being connected in parallel. Of course, there may be more than two adsorption chambers depending on the desired application and depending on the desired stream of oxygen, for example of the amount of oxygen stream required. By providing at least to adsorption chambers, a continuous stream of oxygen comprising gas being enriched with respect to oxygen may be generated at the outlet of the adsorption chambers. By connecting the at least two adsorption chambers in parallel, at least one adsorption chamber may be used in adsorption mode, whereas at least one adsorption chamber may be used in desorption mode. Consequently, a pressure swing adsorption may be performed in the arrangement according to this embodiment. It is clear to one skilled in the art that by providing more than one adsorption chamber, the outlet of the membrane unit is in fluid communication with the outlets of all adsorption chambers due to the fact that all adsorption chambers have to be purged for desorption purposes.
In a further preferred embodiment of the present invention, the oxygen separation adsorbent comprises a zeolite material. These materials exhibit good adsorption properties with respect to nitrogen, for example, allowing getting suitable results of an enrichment of the oxygen comprising gas with respect to oxygen. Additionally, these materials do not interact with oxygen thus not releasing toxic substances in the stream of oxygen comprising gas. Consequently, the arrangement according to the invention may be used in therapeutic applications.
In a further preferred embodiment of the present invention, the membrane is based on a material having a perovskite or fluorite crystal structure. It is especially preferred, that the membrane is based on a perovskite, the perovskite being chosen from the group comprising Sr 1-y Ba y Co 1-x FexO 3-z , which can be undoped or doped with donors or acceptors and La 1-y Sr y Fe 1-x Cr x O 3-z , which can be undoped or doped with niobium, magnesium, titanium or gallium, Sr 1-y-x Ba y La x Co 1-b-c Fe b Cr c O 3-z , which can be undoped or doped with e.g. donors or acceptors like niobium, magnesium, titanium or gallium, Ba 1-x Sr x TiO 3-z , which can be undoped or doped with donors or acceptors such as manganese, iron, chromium or any other doping compounds and PbZr 1-x Ti x O 3-z , which can be undoped or doped with donors or acceptors such as iron, niobium, lanthanum, chromium, or any other doping compounds. These kind of ceramic compounds exhibit a good flux of gas and furthermore have an excellent selectivity with respect to oxygen. In detail, if the primary side of the membrane comprising this component may be subjected to an overpressure of air, for example, it will let oxygen pass only. Thereby, it is possible to generate oxygen in a purity of up to 100%.
In a further preferred embodiment of the present invention a gas reservoir is provided between the outlet of the at least one adsorption chamber and the inlet of the membrane unit. This embodiment allows storing the enriched oxygen comprising gas before guiding it to the membrane unit. Consequently, it is possible to guide the oxygen enriched gas to the membrane unit with a pressure which is higher compared to the pressure the oxygen comprising gas is guided through the adsorption chamber. Therefore, a further pressurizing device may be provided between the adsorption chamber and the membrane unit. This embodiment further allows providing a continuous flow of pure oxygen in any case at the outlet of the membrane unit. For example, in case only one adsorption chamber is used, the desorption step of this adsorption chamber may be bridged. Additionally, even in case the step of changing the gas flow between two adsorption chambers is accompanied with a gap in the air stream a continuous stream may be provided at the dense membrane in case two or more adsorption chambers are used.
In a still further embodiment of the present invention, a gas reservoir is provided downstream the outlet of the membrane unit and upstream the at least one adsorption chamber. This allows storing purified oxygen and guiding the latter to the desired application when it is required. In therapeutic applications, for example, it may be preferred to provide an intermittent stream of pure oxygen. During these times, the full stream of oxygen being generated at the membrane unit may be guided to the required application. During the time of a gap however, the stream of oxygen may be guided into the reservoir thereby filling the latter. Consequently, a full stream of oxygen may be provided both for purging and for application purposes. Alternatively, the oxygen may be guided directly into the gas reservoir and further on to desired application as well as to the at least one adsorption chamber. Therefore, the gas reservoir may comprise two outlets. It is thus ensured that at each time of the method according to the invention a sufficient stream of oxygen may be guided both to the application and to the adsorption chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
In the drawings:
FIG. 1 shows a schematic cross sectional view of an arrangement according to the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
In FIG. 1 , an arrangement 10 for generating oxygen is schematically shown. The arrangement 10 may be used for generating oxygen with respect to therapeutic applications, for example in the field of COPD treatment. The arrangement 10 may be designed as a stationary arrangement, for example for using it in a hospital, or it may be a portable device, for example for using it in the field of homecare applications. However, the arrangement 10 may furthermore be used for any application at which pure or essentially pure oxygen has to be provided, for example in air planes or for welding purposes.
The arrangement 10 comprises at least one adsorption chamber 12 . However, it is preferred that the arrangement 10 comprises at least two adsorption chambers 12 , 14 , the adsorption chambers 12 , 14 being connected in parallel. In the following, the invention is described with respect to two adsorption chambers 12 , 14 . However, it is clear for one skilled in the art that every feature may be provided correspondingly by using just one adsorption chamber 12 or more than two adsorption chambers 12 , 14 . Each adsorption chamber 12 , 14 is equipped with an oxygen separation adsorbent 16 , 18 . The oxygen separation adsorbent 16 , 18 is configured for letting oxygen pass but for interacting with, or adsorbing, respectively other components being present in an oxygen comprising gas. In case air is used as oxygen comprising gas, it is thus preferred that the oxygen separation adsorbent 16 , 18 is configured for adsorbing nitrogen. Suitable oxygen separation adsorbents 16 , 18 may comprises a zeolite material. However it may be possible to use every suitable oxygen separation adsorbent known in the art for swing processes, such as pressure swing adsorption ore vacuum swing adsorption.
Each adsorbent chamber 12 , 14 has an inlet 20 , 22 for inserting oxygen comprising gas into the adsorption chamber 12 , 14 and an outlet 24 , 26 for guiding enriched oxygen comprising gas out of the adsorption chamber 12 , 14 . Therefore, the inlets 20 , 22 of the adsorption chambers 12 , 14 are connected to an inlet 28 of the arrangement 10 . Connected to the inlet 28 may be a source of oxygen comprising gas, such as a gas storing device. However, there may simply be a pump which guides the surrounding air into the inlet 28 . Starting from the inlet 28 , a conduit 30 is connected to the inlet 28 as well as to the inlet 20 of the first adsorption chamber 12 , whereas a conduit 32 is connected to the inlet 28 and the inlet 22 of the second adsorption chamber 14 . Furthermore, the outlet 24 of the first adsorption chamber 12 is connected to a conduit 34 which in turn is connected to an outlet conduit 40 , whereas the outlet 26 of the second adsorption chamber 14 is connected to a conduit 36 which in turn is connected to the outlet conduit 40 . Consequently, the adsorption chambers 12 , 14 are connected in parallel. It is apparent to one skilled in the art that a respective arrangement may be formed by using more than two adsorption chambers 12 , 14 .
In order to allow the oxygen comprising gas to be guided through the adsorption chambers 12 , 14 intermittently, a valve 42 may be provided in the conduit 30 and a further valve 44 may be provided in the conduit 32 . A valve according to the invention shall be any device which may allow a gas flow, inhibit a gas flow and/or regulate the amount of a gas flow. Consequently, by closing the valve 42 and by opening the valve 44 , the oxygen comprising gas may be guided through the second adsorption chamber 14 , whereas the oxygen comprising gas may be guided through the first adsorption chamber 12 by opening the valve 42 and by closing the valve 44 . Correspondingly, a valve 46 may be provided in the conduit 34 and a valve 48 may be provided in the conduit 36 . By guiding the oxygen comprising gas through the first adsorption chamber 12 , the valve 46 should be opened whereas the valve 48 should be closed. Correspondingly, by guiding the oxygen comprising gas through the second adsorption chamber 14 , the valve 48 should be opened whereas the valve 46 should be closed. This ensures that the enriched oxygen comprising gas is guided solely into the outlet conduct 40 .
The arrangement 10 thus allows intermittently guiding a stream of oxygen comprising gas through at least one adsorption chamber 12 , or through more than one adsorption chamber, for example two adsorption chambers 12 , 14 being equipped with an oxygen separation adsorbent 16 , 18 thereby enriching the oxygen comprising gas with respect to oxygen. In that way, an adsorption mode and a desorption mode of the at least one adsorption chamber, or adsorption chambers 12 , 14 , respectively, is defined. Particularly, the stream of oxygen comprising gas is guided alternately through at least two adsorption chambers 12 , 14 being connected in parallel. It may be preferred that the oxygen comprising gas is enriched with respect to oxygen in the adsorption chamber to an oxygen concentration in the range of ≦88%, particularly in the range of ≦75%, especially preferred in the range of ≦50%.
Downstream the outlet conduit 40 , the arrangement 10 further comprises a membrane unit 50 , wherein the outlets 24 , 26 of the adsorption chambers 12 , 14 are in fluid communication with an inlet 51 of the membrane unit 50 . It may be preferred that a gas reservoir 49 is provided between the outlets 24 , 26 of the adsorption chambers 12 , 14 and the inlet 51 of the membrane unit 50 . Especially by providing just one adsorption chamber 12 , the gas reservoir 49 may allow generating a continuous gas stream. It is furthermore preferred that the oxygen comprising gas is guided to the at least one adsorption chamber 12 by use of an overpressure. This allows in one step guiding the enriched oxygen comprising gas into the membrane unit 50 and creating a stream of gas through the membrane unit 50 like it will be apparent down below. Therefore, an overpressure of ≧0.2 bar to ≦2 bar may be preferred.
The membrane unit 50 comprises a dense membrane 52 in order to separate oxygen from the remaining components of the enriched oxygen comprising gas coming from the adsorption chambers 12 , 14 and thus being enriched with respect to oxygen. To achieve these properties, the membrane 52 may be a solid ceramic membrane comprising selected inorganic oxide compounds. Preferable membranes 52 are based on a perovskite or fluorite crystal structure. As an example, the perovskite may be chosen from the group comprising Sr 1-y Ba y Co 1-x FexO 3-z , which can be undoped or doped with donors or acceptors and La 1-y Sr y Fe 1-x Cr x O 3-z , which can be undoped or doped with niobium, magnesium, titanium or gallium, Sr 1-y-x Ba y La x Co 1-b-c Fe b Cr c O 3-z , which can be undoped or doped with e.g. donors or acceptors like niobium, magnesium, titanium or gallium, Ba 1-x Sr x TiO 3-z , which can be undoped or doped with donors or acceptors such as manganese, iron, chromium or any other doping compounds and PbZr 1-x Ti x O 3-z , which can be undoped or doped with donors or acceptors such as iron, niobium, lanthanum, chromium, or any other doping compounds. As a preferred example, the perovskite-related material Ba 0.5 Sr 0.5 Co 0.5 Fe 0.2 O 3-δ (BSCF) is very well suited. As an alternative, for example, a Sr 0.5 Ba 0.5 Co 0.8 Fe 0.2 O 3-x thin film may be used. Especially in case such membranes 52 are used, it may be required to heat the dense membrane 52 to a temperature at which it is permeable for oxygen. This may be realized in a direct way, for example by providing a heating device for heating the membrane 52 , or in an indirect way, by heating the oxygen comprising gas and heat the membrane 52 by the influence of the hot gas. However, in the last case it is preferred to heat the oxygen comprising gas downstream the adsorption chamber 12 , or the adsorption chambers 12 , 14 , respectively, due to the fact that a hot gas will deteriorate the adsorption step. Consequently, it may be preferred to combine a heating device with a gas reservoir 49 or with a further pump being arranged upstream the membrane unit 50 .
The membrane 52 comprises a primary side, which may be visualized by a primary membrane chamber 54 , and the membrane 52 further comprises a secondary side, which may be visualized by the secondary membrane chamber 56 . The membrane 52 is dense which means that the oxygen is separated from the remaining components of the enriched oxygen comprising gas. In order to guide the enriched oxygen comprising gas into the membrane unit 50 and to the primary side of the membrane 52 , the inlet 51 is arranged at the primary side of the membrane 52 .
Consequently, on the primary side of the membrane 52 , a stream of gas is generated which is depleted with respect to oxygen. This gas stream may leave the primary membrane chamber 54 through an outlet conduit 58 . The outlet conduit 58 may thereby be equipped with a valve 60 to allow using a required pressure in the primary membrane chamber 54 as well as regulating the egress of the stream of gas out of the primary membrane chamber 54 .
Correspondingly, due to the fact that a gas flow through the dense membrane 52 is generated to its secondary side thereby separating the oxygen from the enriched oxygen comprising gas, on the secondary side of the membrane 52 , i.e. in the secondary membrane chamber 56 , a stream of pure, or at least essentially pure oxygen is formed. The generated oxygen may leave the membrane unit 50 through an outlet 62 being arranged at the secondary side of the membrane 52 and through an outlet conduit 64 and may be delivered to the desired application. For example, the oxygen may be delivered to an administration device, such as a mask, or it may be stored in a gas storing device.
In the outlet conduit 64 , a valve 66 , such as a three way valve may be provided. This valve 66 allows not only to guide the oxygen to the desired application, but also into a further conduit 68 in any desired ratio. Furthermore, the membrane unit 50 may have two separate outlets at the secondary side of the membrane 52 , one being connected to the outlet conduit 64 and one being connected to the conduit 68 . Preferably, both outlets are equipped with respective valves allowing guiding a required stream of oxygen in each conduit 64 , 68 . Alternatively, a gas reservoir may be provided downstream the outlet 62 of the membrane unit 52 . For example, the gas reservoir may be equipped with two outlets, one being connected to the outlet conduit 64 and one being connected to the conduit 68 . Again, the gas reservoir allows not only guiding the oxygen to the desired application, but also into the conduit 68 in any desired ratio. The conduit 68 allows the outlet 62 of the membrane unit 50 being in fluid communication with the outlets 24 , 26 of the adsorption chambers 12 , 14 , or with the outlet of one single adsorption chamber 12 , respectively. Therefore, the conduit 68 comprises two branch conduits 70 , 72 each having a valve 74 , 76 . The branch conduit 72 is connected to the conduit 34 downstream the outlet 24 of the adsorption chamber 12 but upstream the valve 46 , whereas the branch conduit 70 is connected to the conduit 36 downstream the outlet 26 of the adsorption chamber 14 but upstream the valve 48 , in the flow direction of the oxygen comprising gas. The conduit 68 may thus guide oxygen into the adsorption chambers 12 , 14 , respectively, being in desorption mode in a direction being reversed with respect to the direction of the stream of oxygen comprising gas.
In order to ensure that at least a part of the generated oxygen is guided through the respective adsorption chamber 12 , 14 , being in desorption mode in order to desorb the adsorbed substances, the valves 46 , 48 , 74 , 76 may be regulated, dependent on which adsorption chamber 12 , 14 is in desorption mode or in adsorption mode, respectively. For example, in case the adsorption chamber 12 is in adsorption mode, the oxygen is guided through the adsorption chamber 14 being in desorption mode. In this case, the valves 46 , 74 are open, whereas the valves 48 , 76 are closed. Correspondingly, in case the adsorption chamber 14 is in adsorption mode, the oxygen is guided through the adsorption chamber 12 being in desorption mode. In this case, the valves 48 , 76 are open, whereas the valves 46 , 74 are closed.
Downstream the adsorption chambers 12 , 14 , with respect to the above described flow direction of the oxygen as purging gas, an outlet conduit 80 being equipped with a valve 82 is connected to the conduit 30 and an outlet conduit 84 being equipped with a valve 86 is connected to the conduit 32 . By opening or closing the respective valves 82 , 84 , the purging gas together with the desorbed substances, for example nitrogen, may be egressed out of the arrangement 10 . In detail, in case the adsorption chamber 12 is in adsorption mode whereas the adsorption chamber 14 is in desorption mode, the valve 82 is closed and the valve 86 is opened. Correspondingly, in case the adsorption chamber 14 is in adsorption mode whereas the adsorption chamber 12 is in desorption mode, the valve 86 is closed and the valve 82 is opened.
Additionally, the purging step of the adsorption chamber 12 or the adsorption chambers 12 , 14 may be performed by using both the stream of oxygen coming from the conduit 68 and thus from the membrane unit 50 and a stream of oxygen or oxygen comprising gas coming from a gas source being arranged outside the arrangement 10 . In detail, a source of oxygen comprising gas may be used like known from the state of the art, for example, a gas cylinder of oxygen may be used. However, every purging gas can be used known for desorbing nitrogen, for example, from the oxygen separation adsorbent 16 , 18 . Consequently, a common purging gas may be guided into the adsorbent chambers 12 , 14 together with the stream of oxygen either from the same side, i.e. through the outlets 24 , 26 , or from opposite sides, i.e. additionally through the inlets 20 , 22 . In the last case a further outlet may be preferred which is used for guiding the purging gases out of the adsorbent chambers 12 , 14 for example in the middle part of the latter. This embodiment enables to increase the performance of a common purging step, thereby using a common purging gas as one source, for example as main source, and additionally a small part of the generated oxygen only.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.
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The invention relates to a method of generating oxygen. The method comprises the steps of: intermittently guiding a stream of oxygen comprising gas through at least one adsorption chamber ( 12 ) being equipped with an oxygen separation adsorbent ( 16 ), thereby defining an adsorption mode and a desorption mode of the at least one adsorption chamber ( 12 ), and thereby enriching the oxygen comprising gas with respect to oxygen, guiding the enriched oxygen comprising gas to a primary side of a dense membrane ( 52 ), heating the dense membrane( 52 ) to a temperature at which it is permeable for oxygen, generating an oxygen flow through the dense membrane ( 52 ) to its secondary side, thereby separating the oxygen from the enriched oxygen comprising gas and forming a stream of oxygen. According to the invention, the invention further comprises the step of guiding at least a part of the generated oxygen through the at least one adsorption chamber ( 12 ) being in desorption mode. The method according to the invention allows generating oxygen in a high purity, thereby being energy saving, cost saving and being performable in a compact device.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent application Ser. No. 14/194,712, filed Mar. 1, 2014, which is a continuation-in-part of, claims the benefit of and priority from U.S. patent application Ser. No. 14/069,169, filed Oct. 31, 2013 and provisional patent application Ser. No. 61/720,605, entitled Stroller with Expandable Cargo Area, filed Oct. 31, 2012, the disclosures of which are incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to baby strollers, and more particularly baby strollers which can be expanded or configured in such a way as to provide additional storage capabilities.
BRIEF DESCRIPTION OF THE INVENTION
[0003] The present invention relates to a baby stroller with enhanced capabilities for storage and/or multi-child configurations. The stroller in the present invention is capable of expanding from the rear, thereby creating a cargo space, and, thus, providing the ability to simultaneously transport a passenger such as a child, multiple children, as well as additional cargo, with or without passengers, using simple actuation mechanisms.
SUMMARY
[0004] Broadly, the present invention provides for a stroller for carrying a user, having a front frame member for supporting a seat. In one embodiment, there is a foldable rear member which folds down to create an additional base member. The foldable rear member can be actuated via a mechanism located at or near the rear frame, the nexus of the rear frame and base member, or the handle. In an alternative embodiment, there is a rear member which can expand by means of telescopically or slide-wise actuating a handle. In a third embodiment, there is an additional support member coupled between the front and rear frame member which expands to form an additional support when the base is expanded. In many embodiments, this cargo area is designed for flexibility, so that its size may be adjusted. Further, in some embodiments, the extendable cargo area includes additional seating capacity for one or more additional children.
BACKGROUND
[0005] Baby strollers have been known and used for a number of years to provide a comfortable device to move a baby or small child. The trend with baby strollers has been to reduce the size of the stroller, thus allowing it to be stored more easily. However, with the reduction of size has come the reduction of space that the strollers provide for carrying additional cargo, or multiple children. There remains the need for a baby stroller that can accommodate a large volume of goods and/or a secondary child, while still folding to a compact state.
[0006] U.S. Pat. No. 4,878,680 describes a convertible car seat and stroller combination apparatus comprising a padded child's seat having a telescopic U-shaped handle extending upward from behind the back of the seat, and a perimeter frame having four wheels extendible downward. The apparatus is distinguishable from the present invention at least in being limited to one occupant and requiring a perimeter frame for the wheels, as well as lacking an extendable cargo area.
[0007] U.S. Pat. No. 4,896,894 describes a stroller car seat apparatus comprising a conventional infant seat having a safety harness, a U-shaped padded front guard bar, a U-shaped telescoping handle in the rear, a pivoting front footrest, and a folding rectangular scissors framework with four wheels. The apparatus is distinguishable from the present invention at least in being limited to one child, requiring an obtrusive lower framework, and lacking an extendable cargo area. [0010] U.S. Pat. No. 5,360,221 describes a baby carriage convertible to a safety car seat with a harness comprising a body assembly including a seat, a back, a footrest, and side plates. A wheel assembly is pivotally mounted on the body assembly and adapted to be folded back. A handle assembly is pivotally mounted on the body assembly and adapted to be rotated into a horizontal position. A locking assembly locks and releases the wheel assembly. When the carriage is converted into a safety seat, the wheel assembly is released and folded back, and the handle assembly is rotated into a horizontal position to be used as an arm rest plate. The apparatus is distinguishable from the present invention at least in being limited to one child, requiring the rotation of the handle assembly to serve as an arm rest, and lacking an extendable cargo area.
[0008] U.S. Pat. No. 5,478,096 Chien Ting describes a collapsible multi-use baby carriage having a structure transformable into a dining chair, a safety seat in a car, a cradle, and a bed comprising a seat, a backrest pivotally connected with the seat to change the angle of the backrest, a U-shaped hand rest pivotally connected with the backrest. The structure has a pushing handle, two opposite telescopic side tubes with a windable support plate between the side tubes, and a winding tubular shaft housed in a front tube of the hand rest for pulling out for supporting food. Two front and rear casters are pivotally connected with the bottom of the seat and foldable to the seat bottom. The carriage is distinguishable from the present invention at least in being limited to one child, requiring a windable support plate and two opposite side tubes, and lacking an extendable cargo area.
[0009] U.S. Pat. Nos. 6,523,840, 6,669,212 B2 and 6,523,840 B1 (related patents) describe a combined shopping cart stroller, with a frame that includes a primarily horizontal lower frame portion having a forward end and a rearward end; a curved upper frame portion; vertical support extending between the lower frame portion and upper frame portion; a seat mounted to the frame; and a primary cargo area, which is defined as the space generally bounded by the lower frame portion and the upper frame portion rearward of the seating area. The shopping cart stroller is distinguished from the present invention at least in the front frame not extending to a point above the rearward frame when the cargo space is engaged, the manner in which the primary cargo space extends, as well as the fact that the primary cargo space is unable to support the weight of an additional child.
[0010] U.S. Pat. No. 7,188,858 B2 describes a collapsible stroller, with a frame having left and right sides, each side comprising: an elongated bottom member; a front leg; a push arm; and a support strut, wherein the front leg, the push arm, and the support strut pivot relative to each other when the stroller moves between the open position and the folded position. The stroller is distinguishable from the current invention at least in being limited to one child, and not having an extendable rear cargo space.
[0011] U.K. Patent Application No. GB 2 262 914 A published on Jul. 7, 1993, describes a molded child seat for a vehicle and convertible into a pushchair comprising a supporting frame having two triangular lateral sub-frames interconnected by cross rails. Each sub-frame is equipped with a pair of mounting pins adapted to engage with appropriately shaped and positioned slots on the wheeled pushchair frame. The apparatus is distinguishable from the present invention at least in being limited to one child, requiring a separate supporting frame, and lacking an extendable cargo area.
[0012] U.S. Pat. No. 5,544,904 discloses a convertible stroller and shopping cart having a stroller portion and a shopping cart portion. The stroller portion includes a seat secured to a metal frame, and the shopping cart portion comprises a collapsible receptacle. The receptacle can be oriented in two orientations, a stowed orientation adjacent the seat and a deployed orientation over the seat. When the receptacle is deployed, it conforms to the seat, creating a shopping cart from the stroller. The convertible stroller is distinguishable from the present invention at least in lacking the capacity to carry a second child, and in the fact that the extendable cargo area extends to occupy the same volume as the child seat when extended.
[0013] U.S. Pat. No. 6,669,212 discloses a cart having a frame member including upright and lateral frame portions. A platform is attached to the lateral frame portion and a stationary seat assembly is secured to the upright frame portion. The stationary seat assembly includes a rearward facing stationary seat, a handle and a safety bar between the seat and the handle. A pivoting mechanism is mounted to the lateral frame portion remote from the upright frame portion. The pivoting mechanism is moveable between a substantially upright position and a retracted position and is located relative to a back portion of the seat. A flexible receptacle is attached to the pivoting mechanism, and moves between an open and collapsed position when the pivoting mechanism is moved between the substantially upright and the retracted position, respectively. The stationary seat and the platform are accessible when the pivoting mechanism is in the substantially upright position or the retracted position. The cart is distinguishable from the present invention at least in that the present invention is fully collapsible, can accommodate a second child, and in having an extendable cargo area which includes an extendable base component.
[0014] U.S. Pat. Nos. 6,378,891 and 6,170,854 disclose a convertible stroller and shopping vehicle having a stroller portion and a shopping vehicle portion. The stroller portion includes a seat which is movable from a deployed position to a stowed position. In the deployed position, the invention is used as a stroller. The shopping vehicle portion includes a collapsible receptacle that can be oriented in one of two orientations. In an open orientation, the receptacle creates a shopping cart while in a collapsed orientation the invention can be used to transport bulk materials. The convertible stroller is distinguishable from the present invention at least by lacking the capacity to carry a second child, and in the fact that the extendable cargo area extends to occupy the same volume as the child seat when extended.
[0015] U.S. Pat. No. 8,070,180 (which has the same inventor as the present invention) discloses a stroller for carrying a user, and having an expandable storage space located between the child seat and the rearmost frame members. This may include a first and second front frame member for supporting a seat or seats and back support member, a first and second back frame member being connected to the first and second front frame member, an expandable base member, which connects between the first and second front frame member and the first and second back frame member. The expandable frame member may move between an extended and a retracted position to provide a storage area. This invention discloses a stroller with an expandable storage space, however, the volume of the storage space is not adjustable, he invention does not provide mechanisms for actuating the deployment of the extendable cargo area, the invention does not provide a rear handle lock to take the load of additional cargo, the invention does not provide a solution for folding the front seat compactly and independently of the rear frame, the invention does not provide methods for compactly folding the upper expandable basket, and the invention does not provide for additional seating configurations within the expandable storage space.
[0016] U.S. Pat. No. 6,676,140 B1 discloses a two-seat collapsible stroller comprising a telescopically collapsing rear section that roughly slides into the front section such that the seat nests onto the front seat in the collapsed position. This stroller differs from the present invention at least in that the second seat is a mandatory part of the invention, and no extendable cargo area exists.
[0017] U.S. Pat. No. 8,366,141 discloses a stroller with a collapsible seat for a second child, comprising a complex coupling mechanism that enables the collapse and expansion mechanism. It is distinguishable from the present invention at least in that the stroller's collapse mechanism for the second seat is substantially more complex than in the present invention, and in that it does not provide for the option of an extendable cargo area.
[0018] In general, the prior art contains a series of weaknesses which the present invention addresses. First, most prior art lacks the capacity to form an extendable cargo area while simultaneously carrying even a single child: the cargo area extends into the area where the child would sit. Second, those few inventions designed to include a second child both lack the flexibility to also include extendable storage, and include complex or inflexible deployment mechanisms which prevent the strollers from being deployed easily and/or folded into compact form. The present invention, as will be shown, is capable of simultaneously carrying a child and having the cargo area extended/deployed in a way that can handle heavy loads, is easily expanded via actuation mechanisms, is of such a nature that it can also function as additional seating space for additional children. Finally, the present invention is designed to be easily folded into a compact state for travel or storage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which, like reference numerals identify like elements, and in which:
[0020] FIG. 1 illustrates a side elevational view of the preferred embodiment of the stroller in a retracted position;
[0021] FIG. 2 illustrates a side elevational view of the preferred embodiment of the stroller with the rear member expanded;
[0022] FIG. 3 a . illustrates a side elevational view of an alternative embodiment of the stroller, in which the rear member is not expanded, and in which a cable, being connected to an extendable handle and extendable base member, runs through the frame, so that a user can engage the rear extendable member by actuating the handle;
[0023] FIG. 3 b . illustrates a side elevational view of an alternative embodiment of the stroller, in which the rear member is in the process of being expanded;
[0024] FIG. 3 c . illustrates a side elevational view of an alternative embodiment of the stroller in which the rear member is shown being further expanded;
[0025] FIG. 3 d . illustrates a side elevational view of an alternative embodiment of the stroller in which the rear member is shown fully expanded;
[0026] FIG. 4 illustrates a side elevational view of an alternative embodiment of the stroller, in which the rear member is not expanded, in which an expandable frame member is engaged via sliding support members and joint members;
[0027] FIG. 5 illustrates a rear perspective view of an alternative embodiment of the stroller as illustrated in FIG. 11 , in which the rear member is not expanded;
[0028] FIG. 6 illustrates a side elevational view of an alternative embodiment of the stroller as illustrated in FIG. 11 , in which the rear member is in the process of being expanded;
[0029] FIG. 7 illustrates a rear perspective view of an alternative embodiment of the stroller as illustrated in FIG. 11 , in which the rear member is in the process of being expanded;
[0030] FIG. 8 illustrates a side elevational view of an alternative embodiment of the stroller as illustrated in FIG. 11 , in which the rear member is fully expanded;
[0031] FIG. 9 illustrates a rear perspective view of an alternative embodiment of the stroller as illustrated in FIG. 11 , in which the rear member is fully expanded;
[0032] FIG. 10 illustrates a side elevational view of an alternative embodiment of the stroller as illustrated in FIG. 11 , where the stroller is in a folded position;
[0033] FIG. 11 illustrates a rear perspective view of an alternative embodiment of the stroller as illustrated in FIG. 11 , where the stroller is in a folded position.
[0034] FIG. 12 illustrates an alternative embodiment of the stroller having selectively foldable front frame members.
[0035] FIG. 13 illustrates an alternative embodiment of the stroller having a rear child seat.
[0036] FIG. 14 illustrates a specific alternative embodiment of a basket for the stroller.
[0037] FIG. 15A illustrates a specific exemplary embodiment of a rear handle lock of the stroller.
[0038] FIG. 15B illustrates the lock of FIG. 15A assembled.
[0039] FIG. 15C illustrates the lock of FIG. 15B in an exploded view.
[0040] FIG. 16 is a diagrammatic illustration side view of a stroller of the present disclosure in a retracted position and an expanded position.
[0041] FIG. 17 provides various views of the telescopic members of a stroller of the present disclosure.
[0042] FIG. 18 is a diagrammatic illustration perspective view of a detail of the stroller of FIG. 1 .
[0043] FIG. 19 is a diagrammatic illustration perspective view of a detail of the detail of FIG. 3 .
[0044] FIG. 20 is a diagrammatic illustration perspective view of a detail of the male and female telescoping members of a stroller of the present disclosure.
[0045] FIG. 21 is a diagrammatic illustration transparent view of a detail of the male and female telescoping members of a stroller of the present disclosure.
[0046] FIG. 22 is a diagrammatic illustration side view and detail of a stroller telescoping member locking mechanism of the present disclosure.
[0047] FIG. 23 is a diagrammatic illustration side view of a stroller of the present disclosure with the base in a retracted position, intermediate position, and an expanded position.
[0048] FIG. 24 is a diagrammatic illustration side view of a stroller of the present disclosure with the handle members in a retracted position and an expanded position.
[0049] FIG. 25 is a perspective view schematic illustration of telescopic member locking mechanism of the present disclosure.
[0050] FIG. 26 is a perspective view schematic illustration of a female telescopic member for a locking mechanism of the present disclosure.
[0051] FIG. 27 is a front view schematic illustration of a male telescoping member for a locking mechanism of the present disclosure.
[0052] FIG. 28 is a perspective view schematic illustration of stroller frame portion with lockable telescoping members of the present disclosure.
[0053] FIG. 29 is a side view schematic illustration of a telescopic tube assembly of the present disclosure.
DETAILED DESCRIPTION
[0054] The following description of the preferred embodiment or embodiments is not intended to limit the scope of the invention to the precise form or forms disclosed, but instead is intended to be illustrative of the principles of the invention so that others skilled in the art may follow its teachings.
[0055] FIG. 1 illustrates a stroller 100 in accordance with the teachings of the present invention without the rear member engaged, shown at a side elevational view. FIG. 1 illustrates a base main frame member 101 roughly parallel to the ground, a diagonal main frame member 102 , and a rear main frame member 103 roughly perpendicular to the ground. The main frame section of the present invention, comprised of members 101 , 102 , and 103 is comprised of two mirror sides, connected by cross members. The bottom end, or a section substantially near the bottom end of frame member 103 is connected to frame member 101 at or substantially near the rear end of frame member 101 . In the present embodiment, frame members 101 and 103 are connected at or substantially at a right angle, so that frame member 101 is parallel or substantially parallel to the ground, and frame member 103 is vertical or substantially vertical. In some embodiments, the angle at which frame members 101 and 103 are connected may be substantially acute or obtuse. In some embodiments, frame member 103 may attach near the middle or front of member 101 . In some alternative embodiments, frame member 103 may be located generally midway along member 101 . In some alternative embodiments, frame member 103 may be located near the nexus of member 101 and 104 . In some alternative embodiments, frame member 103 may not be present.
[0056] FIG. 1 further illustrates frame member 102 , which connects to frame members 101 and 103 to complete the main frame section. FIG. 1 illustrates that the top, or a section substantially near the top, of frame member 102 is connected at or substantially near the top of frame member 103 , and the bottom, or a section substantially near the bottom, of frame member 102 is connected at or substantially near the front of frame member 101 . In some alternative embodiments, frame member 103 may be joined to frame member 102 at alternative locations, such as nearer to the middle or front of frame member 102 . One skilled in the art will recognize that the location of the connections between members 102 and 103 , and 101 and 103 will largely determine the angle of 103 .
[0057] In the present invention, members 101 , 102 , and 103 are made out of a single piece of material. In alternative embodiments, member 101 , 102 , and 103 may be composed of two or more separate components, so as to change the angle of the handle of the stroller, and to enable folding (see FIGS. 5 a - d , 6 , 12 , and 13 ). The means with which frame members 101 , 102 , and 103 are connected can be by screws, brackets, welds, rivets or any other suitably strong means. Additionally, frame members 101 , 102 , and 103 may be made of metal, plastic, or any other suitably strong material. In alternative embodiments, there may be handles connected at or near the junctions of frame members 102 and 103 , or at the top-rearmost end of member 102 . Furthermore, the handle may serve as a cross-member, linking the mirrored frames of the invention.
[0058] FIG. 1 illustrates that the wheel members 105 are attached at or around the junctions of frame members 101 and 102 , and 101 and 103 . In the present embodiment, wheel members 105 can rotate freely 360 degrees along the axis (as, e.g., swivel wheels). In alternative embodiments, the wheels can have other degrees of rotational freedom. FIG. 1 illustrates seat member 104 , which is attached to frame member 102 . Seat member 104 may be made from a flexible material, for example fabric or durable plastic cloth. Alternatively, seat member 104 may be made from a harder material, for example solid plastic, metal, or any other suitable material, and may or may not be covered with a padding material for child comfort. The present invention shows seat member 104 containing a canopy, in order to protect a child from sun, rain, or any other weather. In a preferred embodiment, this canopy is retractable, allowing the child to enjoy pleasant weather. In alternative embodiments, this canopy may be fixed in a way so that it cannot be retracted, or it may be absent altogether. In alternative embodiments, seat member 104 may be replaced by at least one seat attachment device, in which alternate seat configurations such as modular seats, car seats, carry cots or alternate child restraint systems may be mounted to the seat attachment device and or frame support members.
[0059] FIG. 1 additionally illustrates a foldable base member 106 , which folds and/or pivots out to form a rear base member. FIG. 1 shows this rear member in a retracted position, so that the rear member is not engaged. FIG. 1 illustrates member 106 attached to the main frame section at or substantially near the nexus of main frame members 101 and 103 . In alternative embodiments, member 106 may be attached to member 101 , or the wheel/wheel assembly of member 105 . In the current embodiment, member 106 is deployed via actuator 150 , which engages cable 120 to release pin 141 . In alternate embodiments, the location of actuators and locking devices or cables may be at any point along the frame or wheel members. In alternate embodiments, actuators may be levers, buttons, or any other suitable device for deploying member 106 . When folded up, member 106 may sit substantially vertical, and flush up against frame member 103 , and when folded down, member 106 may sit substantially parallel to the ground, aligned to be roughly parallel with frame member 101 . In alternative embodiments, stowed, member 106 may sit parallel to member 101 , or at any suitable position between members 101 and 103 . Member 106 can be constructed of metal, plastic or any other suitably strong material so as to support the weight of a child and/or any additional items carried in the cargo area when the stroller is configured as such. The present invention shows member 106 as being a single piece of material. In alternative embodiments, member 106 may be comprised of multiple parts, so as to be telescopic (retracting and extending), slideable, or otherwise shortenable so as to be less noticeable when folded up. Additionally, member 106 may be made so as to be completely detachable. In some embodiments, member 106 may be attached via a quick-release mechanism.
[0060] FIG. 1 illustrates a wheel member 107 , which is attached at or substantially near the top of member 106 (when member 106 is folded vertically), so that when folded down, the base of the rear cargo section is more stable because of the support provided by wheel 107 . In alternate embodiments, wheel member 107 may not be attached to member 106 , if member 106 is of a length that does not require additional support. The wheel member 107 can comprise one or a plurality of wheels. In the present embodiment, wheel member 107 can only rotate at a limited angle along the axis (e.g., a limited-movement swivel). In alternative embodiments, the wheel or wheels can have other degrees of rotational freedom.
[0061] FIG. 1 illustrates handle member 109 , which is pivotably affixed to frame member 102 . In alternative embodiments, member 109 may be attached to, or be an integral part of a telescopic expansion of mirrored frame members 102 (as in FIG. 5 ). In some embodiments, handle 109 may be attached to mirrored frame members 103 , or may be attached to, or be an integral part of a telescopic expansion of mirrored frame members 103 . The range of motion at which member 109 can pivot is not limited to particular angles with respect to member ( 103 ) 102 . Additionally, in alternative embodiments, member 109 may be connected to a different member of the main frame section, as long as its primary functionality of providing a comfortable pushing and steering mechanism for the device is maintained Member 109 can be made out of metal, plastic, or any other similarly suitable material. In alternative embodiments, the handle 109 can be shaped differently; with its design not being limited to any particular curved or straight shapes, and in alternative embodiments may be designed as two separate left and right handles (hence not linking mirrored frame members). This handle 109 can be made out of plastic, metal, or some other suitable material, and may additionally be wrapped in foam, rubber, fabric, or some other padding material.
[0062] FIG. 2 illustrates a stroller 100 in accordance with the teachings of the present invention with the rear member in the deployed state. The embodiment shown is similar to that shown in FIG. 1 , but with the rear member folded down along its joint with the structural frame so as to be roughly parallel to the ground and member 101 . FIG. 2 additionally shows the position of wheel member 107 when member 106 is folded down-the wheel is now in contact with the ground so as to provide support for member 106 . Additionally, FIG. 2 illustrates how handle 109 can be constructed to telescopically expand as a means to lengthen the handle. In the illustrated embodiment, the telescopic expansion of handle 109 actuates the deployment of rear member 106 by pulling cable 120 which engages pulley 121 to release pin 141 . In other embodiments, the placement of pin 141 can be located at any location in which release of member 106 or wheel member 107 can occur. In other embodiments, pin 141 may be a lock, clamp, or other retaining mechanism to allow member 106 to move from a stowed to a deployed state (See FIGS. 5A-d for more detail). In alternative embodiments, a lever or button actuation mechanism can release the pin, lock, clamp, or other retaining mechanism holding member 106 , thus allowing it to deploy. In other embodiments, the cable and/or pulley mechanisms may run through or along other frame members, or any combination of frame members which result in deployment of member 106 . The lever or button to release member 106 can be located at many locations along stroller 100 , and may be actuated by hand, by foot, or a combination of the two.
[0063] FIG. 3 a illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view with the rear base member not engaged, and with alternative embodiments in some of the members. FIG. 3 a . illustrates base main frame member 101 , expandable base main frame member 101 b , front frame members 102 and 102 a , and rear main frame member 103 . The main frame section of the present invention is comprised of mirrored structural frames connected by cross members, each mirrored structural frame comprising members 101 , 101 b , 102 , 102 a , and 103 .
[0064] FIG. 3 a . illustrates the base of the stroller 100 as being comprised of frame members 101 and 101 b , and as being substantially parallel with the ground. FIG. 5 a . illustrates frame member 101 as forming the frontward section of the extendable base frame member, and 101 b as forming the rearward section of the extendable base frame member. Members 101 and 101 b are designed to form an expanding base. This is accomplished by having parts 101 and 101 b move parallel relative to one another. In some embodiments, this may be done by having the two components slide (as, e.g., on rails) parallel to each other. In other embodiments, one component may telescope within another. In other embodiments still, one component or another may be made of sub-components which allow the part itself to telescope within itself. Specifically, FIG. 5 a . illustrates frame member 101 fitting inside extendable frame member 101 b . In an alternative embodiment, member 101 b can fit inside member 101 ; in yet another alternative embodiment, member 101 b itself may be composed of multiple, telescoping components. In yet another embodiment, member 101 may have rails on which 101 b moves. In still other embodiments, 101 b may have rails along which 101 moves. In a further embodiment, members 101 and 101 B slide along each other for extension and retraction. The means with which members 101 and 101 b are connected can be by screws, brackets, welds, pins, rails, slots, slides, or any other suitably strong means. Members 101 and 101 b can be made out of metal, plastic, or any other similarly suitably strong material. The bottom end, or a section substantially near the bottom end, of frame member 103 is connected to the extendable frame member 101 .
[0065] In the present embodiment, frame members 101 and 103 are connected at a substantially acute angle in relation to the front of the frame, so that frame member 103 is leaning substantially towards the front of the stroller (see FIG. 5 a .). In alternative embodiments, the angle at which frame members 101 and 103 are connected may be substantially more acute, obtuse, or may form a substantially right angle, with relation to the front of the stroller. The means with which frame members 101 and 103 are connected can be by screws, brackets, welds, pins, or any other suitably strong means. In alternative embodiments, the lower end of member 103 may be attached to extendable member 101 b . In preferred versions of this embodiment, member 103 is slidably attached to extendable member 101 b , so that the movement of member 101 b does not substantially alter the angle at which 103 is attached. Member 103 can be made out of metal, plastic, or any other similarly strong material.
[0066] FIG. 3 a . illustrates frame member 102 , with the bottom end, or a section substantially near the bottom end, of member 102 connecting to the front, or a section substantially near the front, of base frame member 101 . In the present embodiment, members 101 and 102 are connected at a substantially acute angle in relation to the front of the frame, so that frame member 102 is leaning substantially towards the rear of the stroller (see FIG. 5 a ). In alternative embodiments, the angle at which frame members 101 and 102 are connected may be substantially more obtuse, acute, or may form a substantially right angle, with relation to the front of the frame of the stroller, so long as it still forms a sturdy frame to support the potential load on the stroller. Additionally, member 102 can be made out of metal, plastic, or any other similarly strong material.
[0067] FIG. 3 a . illustrates frame member 102 a , with the front of member 102 a connecting to the top of frame member 102 , with the top of member 103 connected to 102 a at about the middle of 102 a 's length, thus completing the main frame section. In alternate embodiments, the nexus point at which frame members connect can be at any optimal geometric position. The means with which frame member 102 a connects to frame members 102 and 103 can be by screws, brackets, welds, pins, pivots, slides, or any other suitably strong means. Additionally, member 102 a can be made out of metal, plastic, or any other similarly strong material.
[0068] FIG. 3 a . illustrates that wheel members 105 are attached at or around the junctions of frame members 101 and 102 , and near the end of 101 b . In alternate embodiments, front wheel placement can be oriented independently to either member 101 , 101 b or 102 respectively. The rear wheels 105 extend along with member 101 b , as it extends to form the rear base member. In the present embodiment, wheel members 105 can rotate freely 360 degrees along the axis, as on, e.g., a swivel. In alternative embodiments, the wheels can have other degrees of rotational freedom.
[0069] FIG. 3 a . illustrates extendable handle member 102 b , cable member 120 , cable connection point 121 ( a and b ), and pulley members 122 , which, in addition to extendable base member 101 b , comprise the means with which the rear base member is extended. Handle member 102 b moves parallel to member 102 a . In a preferred embodiment, this sliding motion is accomplished by making handle member 102 b fit telescopically within 102 a . In alternative embodiments, 102 b slides next to 102 a , as though with rails, slots, slides, or other guides, or may fit inside of 102 b . In yet other embodiments, handle member 102 b comprises multiple pieces and telescopes within itself to contract and extend. Cable connection point 121 a is attached at a point along the length of handle member 102 b , and cable connection point 121 b is attached at a point along the length of 101 b . FIG. 5 a . additionally illustrates cable member 120 , which is the primary mechanism through which the rear base member is engaged and disengaged. Cable member 120 is threaded through or alongside frame members 101 b , 103 , 102 a and 102 b , and is additionally threaded through pulley members 122 in order to connect connection points 121 . FIG. 5 a . illustrates pulley members 122 as being located near the junctions of members 103 and 102 a , and members 103 and 101 b , respectively. Cable member 120 can be made out of metal or some other similarly strong material. The pulley members 122 assist cable member 120 to move smoothly within the frame of the stroller 100 . In alternative embodiments, pulley members 122 may be located at different points within the frame of the stroller, or may be some similarly suitable device for assisting cable member 120 to move smoothly within the frame of the stroller. Pulley members 122 can be made out of plastic, metal, or any other suitably strong material.
[0070] FIG. 3 a . illustrates extendable handle member 102 b in a substantially retracted position. When member 102 b is in a retracted position, the rear cargo area is not engaged; when member 102 b is extended by the user, member 101 b extends via cable member 120 , connection point members 121 and pulley members 122 , thus extending the rear base member 101 b . Additionally, when fully extended, handle 102 b and member 101 b selectively lock into place, so that the rear base member 101 b and handle 102 b are selectively secured to stroller 100 . Attached to the end of handle member 102 b is handle 119 . Handle 119 can be have a variety of possible shapes; with its design not being limited to any particular curved or straight shapes, and in alternative embodiments may be designed as two separate left and right handles, attached to mirrored members 102 b . This handle 119 can be made out of plastic, metal, or any other suitable material, and may additionally be wrapped in foam, rubber, fabric, or any other suitable padding material.
[0071] In the present embodiment, members 102 b and 101 b are extended manually via cable member 120 , in alternative embodiments, some other mechanical device may be used to automatically extend members 102 b and 101 b . In yet other alternative embodiments, springs or some other similarly suitable means to store and release potential energy may be attached to member 102 b or member 101 b to assist the user in engaging the rear base member.
[0072] FIG. 3 b . illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view, with members 102 b and 101 b beginning to be extended to form the rear base member.
[0073] FIG. 3 c . illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view, with members 102 b and 101 b being extended further, so that the rear base member is almost fully engaged.
[0074] FIG. 3 d . illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view, with members 102 b and 101 b in a fully extended and locked position, so that the rear base member is fully engaged.
[0075] FIG. 4 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view, with the rear base member 101 b not engaged, with alternative embodiments in some of the members. Importantly. the stroller 100 illustrated in FIG. 4 has a folding capability (see FIGS. 10-11 ). The stroller 100 is folded via joint locking member 130 , and 128 a , and 128 b . Release of locking joint 130 allows member 103 to fold forward (see FIG. 10-11 ). Release of joint member 128 a , allows members 102 and 102 c to fold downward (see FIGS. 12-13 ). In alternative embodiments, this folding capability may not be present. Frame member 103 , seat member 104 , and wheel members 105 are functionally identical to those illustrated in FIGS. 1-2 and seat member 104 is mounted to members 102 . Additionally, front frame base members 101 and 101 b are functionally identical to those illustrated in FIGS. 3 a - d . FIG. 4 illustrates diagonal frame member 102 , the top of which is connected to a joint member 128 b (see FIG. 6 ), and the bottom, or a section substantially near the bottom, of member 102 being connected to joint member 128 a . FIG. 4 also illustrates diagonal frame member 102 c , the top of which is connected to joint member 128 a , and the bottom, or a section substantially near the bottom, of member 102 c is connected to member 101 . Joint member 128 a allows frame members 102 and 102 c to move from an unfolded position (see FIG. 6 ) to a folded position (see FIGS. 10-11 ). Joint members 128 a and 128 b can be made out of plastic, metal, or any other suitably strong material. FIG. 4 introduces diagonal support frame member 123 . The top of diagonal support frame member 123 is connected with a slide somewhere along frame member 102 , in such a way as to allow it to slide along member 102 ; the bottom of member 123 is connected at, or substantially near, the rear end of base frame member 101 . In alternative embodiments, the points at which member 123 attaches to members 102 and 101 may be different, so long as member 123 is still able to provide structural support for the main frame of the stroller and to slide during folding. In yet another embodiment, the top of member 123 may be attached to member 102 c , instead of member 102 . The means with which member 123 attaches to members 102 (or 102 c ) and 101 can be by slots, screws, clamps, brackets, pins, slides or any other similarly suitable means. Additionally, member 123 can be made out of metal, plastic, or any other suitably strong material. FIG. 4 additionally illustrates footrest member 104 a , which is attached near or substantially near the front end of base frame member 101 . In alternative embodiments, member 104 a may be placed at a different location on the frame of the stroller, or may be connected to seat member 104 . Additionally, member 104 a can be made out of plastic, metal, or any other similarly suitable material, and may additionally be wrapped in foam, rubber, fabric, or some other padding material.
[0076] FIG. 5 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a rear perspective view. FIG. 5 illustrates cross members 115 and 128 ; FIG. 5 additionally illustrates extendable support member 125 . In the current embodiment, member 125 is a three-sided, u-shaped tube. In alternate embodiments, 125 may be parallel tubes connected between the frame members 102 (through joint 128 b ) and 103 without a third tube cross-member. In this embodiment, extendable support member 125 and expandable base frame member 101 b are the primary means with which the rear cargo area is engaged (see FIG. 8 ). In the un-engaged position, the top, or a portion substantially near the top, of extendable bar member 125 is connected to joint member 128 b ; the bottom, or a portion substantially near the bottom, of member 125 is connected to frame member 103 in such a way as to allow it to slide vertically along member 103 and to pivot about that same point. Member 125 is able to move from a closed, substantially vertical, position, to an open, substantially horizontal, position by sliding the base of the u shape vertically along member 103 . As member 125 is lifted along member 103 , it is pushed to a substantially horizontal position (see FIG. 10 ) via joint members 128 b . This creates a new distance between 102 and 103 , which simultaneously causes base member 101 b to move parallel to 101 to extend the base of the frame (see FIGS. 6 and 7 ). which simultaneously expands member 101 b , and thus engages the rear cargo area. In alternative embodiments, there may be springs, pulleys, motors, or some other mechanism which assists the user of the stroller 100 to expand members 125 and 101 b . In alternate embodiments, member 125 may have additional expansion capabilities beyond pivoting upward, such as expanding telescopically while also pivoting into an expanded position, or expanding via hinges. When member 125 is in a closed position, it locks into position. The means with which member 125 locks into place can be by pin, snap, strap, slot, clamp or any other similarly suitable method. Additionally, member 125 can lock into place at various intervals along the height of 103 , to provide for variable expansion. The means with which member 125 locks into place can be by pin, snap, strap, slot, clamp or any other similarly suitable method. Support member 125 can be made out of metal, plastic, or any other similarly strong material.
[0077] FIG. 6 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view, with members 125 and 101 b in the process of being extended to form the rear cargo area. As discussed above, in some embodiments, member 125 may lock in an intermediate position along the height of 103 , thus achieving variable expansion of the base. In another embodiment, the total movement of member 125 may be limited to an intermediate position, with member 125 serving as side frame members once the extendable base has selectively expanded.
[0078] FIG. 7 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a rear perspective view, with members 125 and 101 b being extended to form the rear cargo area.
[0079] FIG. 8 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view with the rear cargo area fully extended. FIG. 8 additionally illustrates basket member 127 , the top of which attaches to member 125 , the front of which attaches to member 128 , and the back of which attaches to member 103 . In alternate embodiments, basket member 127 may attach at or near any frame member, joint, pivot or hub in which attachment renders the basket to a usable state. Member 127 can be made out of fabric or some other similarly soft material, or may additionally be made out of plastic or some other similarly rigid material. Member 127 attaches to the frame of the stroller by snaps, straps, or any other similarly suitable means of attachment.
[0080] FIG. 9 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a rear perspective view, with the rear cargo area fully engaged.
[0081] FIG. 10 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a side elevational view in a folded position. The stroller is folded by releasing joint members 130 via a release mechanism, which allows frame member 103 to fold forward to a substantially horizontal position. Additionally, joint members 128 a and 128 b allows frame members 102 and 102 c to fold downward, thus allowing member 103 to fold fully forward. The mechanism with which joint members 130 are released can be a button, spring, latch, or any other similarly suitable method.
[0082] FIG. 11 illustrates a stroller 100 in accordance with the teachings of the present invention, shown at a rear perspective view in a folded position.
[0083] In addition to the foregoing embodiments, the present invention contemplates other specific exemplary alternative embodiments. For example, FIG. 12 illustrates a specific alternative embodiment of a stroller 100 that provides selectively foldable front frame members 102 / 102 C in which the members are rotatably jointed to create a top portion 102 and a bottom portion 102 C of each front member. An actuator, such as a cable arrangement connected to the rotatable joint of each front member, effects folding of the front members upon actuation. Specific exemplary embodiments further provide a rotatable, front member 102 C extending from bottom frame member 101 which is slidably coupled to support member 102 D, and from which the support member also rotatably pivots to provide support while still allowing the front members to be selectively folded or deployed. Additional specific exemplary embodiments further provide that member 102 C may have a shock or damper system.
[0084] FIG. 13 illustrates an alternative embodiment of a stroller 100 . Specific exemplary embodiments provide the rear cargo area with a foldable child seat 210 that is selectively detachable from the rear cargo area. For embodiments which provide floor platform 101 C, platform 101 C provides a floor upon which a child may step up to access the chair, or stand, as the case may be. For safety and other considerations, specific exemplary embodiments of the stroller, platform 101 C is cropped to extend less than the full length of member 101 B.
[0085] FIG. 14 illustrates an alternative embodiment of basket 127 . Another specific alternative embodiment provides a selectively foldable basket 400 that is selectively mountable to handle 110 , front frame member 102 , rear frame member 103 , support member 125 , or rear cargo area platform 101 C_. Specific exemplary embodiments of basket 400 have one or more elastic members 410 A, 410 B which mount to 430 A & 430 B respectively, and which are held in place by restraints 420 A and 420 B, which combined cause basket 400 to snap into a more compact position when the basket is folded. Base panels 430 A, 430 B pivot around hinge 440 . Side Panels 450 A, 450 B comprise the upper sides of basket 400 . Members 460 A, 460 B provide a potential surface in which to mount basket 400 to stroller 100 frame members.
[0086] FIG. 15A illustrates a specific exemplary embodiment of a rear handle lock 130 of a stroller 100 . A lock 130 provides, for example, a mechanism consisting of rear frame member 103 (tube), pivot, locking pins, shuttle, locking plates, spring, spring stop, lock actuator, and cable. A rear frame member 103 has slots cut into it to allow limited travel of the pins up and down parallel to the handle and along the center plane of rear frame member 103 . The pivot is a metal pin, for example, that facilitates rotational motion of the rear frame member relative to the locking plates. The locking pins provide the locking bar for restraining the rear frame member's rotation relative to the locking plates. The shuttle may be a plastic part, for example, that slides up and down inside the handle tube and couples the pins so they slide up and down at the same time. The shuttle is constantly pushed upon (downward) by a spring pushing the shuttle and pins into a locked position. The shuttle has a cable attached to it in which a lock actuator on or near the handle pulls the cable and hence moves the shuttle and pins to an unlocked state. The unlocked state is a state in which the pins are now inside the circular track of the locking plate and the rear frame member 103 can now be rotated freely to a non-use state (folded state). The locking plates may be mounted to lower frame member 101 B and may be located on each side of the rear frame members 103 . The locking plates may employ tracks or slide-by-slide translation and locking pockets for the pins to travel in. The pins may be spring loaded to lock into the locking pockets when the handle is rotated to the appropriate angle to line up with the locking pockets. Locking pockets may be designed for both a stowed (folded) state and erected (unfolded) state.
[0087] FIG. 15B illustrates lock 130 assembled.
[0088] FIG. 15C depicts lock 130 in an exploded view.
[0089] In reference now to FIGS. 16-29 :
[0090] Telescopic Tubing with Wheel: A pair of tubes in which one tube 207 is smaller in circumference than the other 209 , and in which the smaller tube 207 houses at least one wheel 211 , and in which the smaller tube 207 contains a slot 213 for the wheel 211 to make contact with interior of the larger tube 209 . In general, the expandable stroller of the present invention comprises two mirror-imaged structural frames connected to each other by cross members. As the cross members may be placed in any suitable position, and since the structural frame members are mirror images, the discussion of the structure of the present invention will focus on a single frame. One skilled in the art will recognize that the description will apply equally to the mirrored frame.
[0091] Each pair of telescopic tubes are configured with at least one wheel (in this case the wheels have ball bearings). The ball bearings ease the movement from the retracted to expanded configurations.
[0092] Telescopic Tubing Expansion with balls: A pair of tubes in which one tube 207 is smaller in circumference than the other 209 , and in which the smaller tube 207 includes at least a set of channels or depressed insets 219 on opposing upper/lower and/or left/right sides, and in which at least two or more balls 215 is set within the channels/insets 219 of the smaller tube 207 and the interior surface 217 of the larger tube 209 , such that when the telescopic tubes move axially relative to each other, movement of the tubes is eased by means of the balls. The interface 221 between the larger 209 and smaller 207 tubes (as well as the tube ends), is preferably sealed in a way to prevent infiltration of dirt and debris.
[0093] Telescopic Tubing Lock Mechanism: A pair of tubes in which one tube 207 is smaller in circumference than the other 209 , and in which the smaller tube 207 slides relative to the larger tube 209 , and in which the smaller tube 207 is locked in a fixed position relative to the larger tube 209 by means of a pin or rod 509 engaging into a tab or slot 513 with a spring mechanism holding the pin/rod into a locked position, and in which releasing tension of the spring disengages the pin/rod from the tab/slot, thus allowing the tubes to slide relative to one another, and in which the design may embody two or more locking positions (tabs and/or slots). Releasing tension on the spring and pin/rod is achieved by pulling cables and/or a secondary mechanism which acts upon the spring. In one embodiment, the spring is located within the place for a spring 503 depicted in FIG. 25 .
[0094] The telescopic tubes each have a locking mechanism, which is actuated at the upper frame 202 of the stroller's front seat 204 . To actuate the cables/locks, the user slides the secondary lock with their thumb and then squeezes the actuation lever. The actuation lever pulls cables on both the right and left sides to release the locks simultaneously. The lock utilizes a spring that is predisposed to stay locked. The cables release tension on the spring, allowing the lock to release.
[0095] The telescopic locking mechanism has three positions in which the pins/bars can lock into place. The initial position ( FIG. 23 , left), the intermediate expansion ( FIG. 23 , center), and the fully expanded position ( FIG. 23 , right). Although our system has three positions, the design itself allows for a multitude of locking positions.
[0096] The locking mechanism can also be used in the other embodiment in which the extendable base is extended by telescopic actuation of the handle ( FIGS. 3A-3D from the converted utility app). In this case, the actuator for the lock may be forward of the telescopic handle (or not a part of it at all), but once the lock is released, telescoping the handle allows the tubes to slide relative to one another into their next locked position.
[0097] The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural, materials, and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
[0098] Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
[0099] The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
[0100] The description has made reference to several exemplary embodiments. It is understood, however, that the words that have been used are words of description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the disclosure in all its aspects. Although description makes reference to particular means, materials and embodiments, the disclosure is not intended to be limited to the particulars disclosed; rather, the disclosure extends to all functionally equivalent technologies, structures, methods and uses such as are within the scope of the appended claims.
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A stroller for carrying a child or child restraint system, that may comprise an additional storage area or child support system when expanded. The frames include a mechanism whereby the base of the frame is expanded rearward to create a storage space roughly behind the baby seat, and optionally where a top to the storage area folds up from the rear of the frame to complete the storage area. The stroller may include detachable wheels. The stroller may also include handles or push bars that may optionally include mechanisms to assist in expanding or contracting the storage area. The stroller may also be constructed so as to be collapsible for storage.
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BACKGROUND OF THE INVENTION
This invention relates to improvements in the rate of melting glass in a tank-type melting furnace whereby the output of a particular furnace may be increased at a given energy consumption, or, conversely, the energy consumption may be reduced for a given throughput. More particularly, the invention deals with improvements in the manner in which raw glass batch materials are fed to a glass melting furnace so as to enhance the rate the raw ingredients are brought to a liquid state.
In a typical glass melting furnace of the regenerative or recuperative type, a body of molten glass is maintained in the furnace and raw glass batch materials are fed through an inlet at one end of the furnace onto the surface of the pool of molten glass. There, the batch materials usually form an unmelted layer on the surface of the molten glass pool which may extend a considerable distance into the furnace until it becomes melted into the pool of molten glass. At the opposite end of the furnace, melted and reacted glass is withdrawn from the pool of molten glass through an outlet opening.
It has been recognized that the floating layer or blanket of unmelted batch ingredients acts as a thermal insulator which limits the rate at which the temperature of the batch is raised sufficiently to enter a liquid state. Therefore, liquefaction of glass batch usually is limited to a relatively thin layer at the surface of the batch blanket. In order to overcome this problem, attempts have been made in the past to increase the surface area of the batch blanket exposed to the flames in the furnace. For example, U.S. Pat. No. 4,030,905 shows an arrangement for plowing furrows transversely across a batch blanket. Such an arrangement may produce an increase in batch surface area and some slight improvement in run-off of melted batch, but possesses certain drawbacks. Plowing the furrows causes batch to be piled up more deeply on either side of each furrow, thereby further insulating the underlying batch from the overhead sources of heat. Furthermore, any enhancement in run-off by plowing is limited because the furrows do not extend to the underlying molten glass and because some of the loose batch material tends to fall back into the furrow behind the plow.
Another approach to breaking up a batch blanket is disclosed in U.S. Pat. No. 3,994,710 wherein an inverted T shaped member is employed to chop the batch blanket into pieces. Such an arrangement appears most suitable for a location relatively far into the furnace where melting of the batch blanket has already progressed to an advanced stage. It would be desirable to improve run-off as early as possible in the melting process. Additionally, by being located within the main body of the melting furnace, the T bar of the patent requires cooling which detracts from any net thermal gains. Also, operating on the batch blanket within the main body of the furnace carries with it the risk of increased carry-over of materials which can have an adverse effect on the walls and regenerator or recuperator system of the furnace. However, carrying out such a chopping operation on an upstream portion of the batch blanket would not appear to be advantageous since the buoyant batch material would be pressed into the molten glass temporarily and then rise again.
Another prior art approach has been to bring the batch ingredients into more intimate contact with the molten glass such as in U.S. Pat. Nos. 2,533,826 and 2,749,666. The object of this approach is to take advantage of conductive heat from the molten glass, but it has now been found that the major source of heat (typically about seventy percent) for melting the batch is the overhead radiant heat from the combustion flames in the furnace. Therefore, covering the batch with molten glass can be disadvantageous in that it reduces the amount of radiant heat received by the batch. It would be desirable to increase rather than decrease the impingement of radiant energy on the batch materials.
Other attempts have been made to improve batch melting by reducing the thickness of the batch blanket such as in U.S. Pat. Nos. 2,327,887; 3,193,119; and 4,004,903. While reducing batch blanket thickness may generally be desirable, the approach in each of these patents has the drawback of reducing surface area exposed to overhead flames and inhibiting run-off of melted batch. Furthermore, in many commercial glass melting operations, a primary objective is to maximize throughput of a given furnace. In such a case, the batch blanket would already cover a maximum area and any reduction in batch blanket thickness would undesirably reduce the throughput of the furnace. The last mentioned patent overcomes this dilemma somewhat by compacting the batch blanket, but, nevertheless, a flat upper surface is the result.
It is also known to produce a plurality of discrete batch piles by employing a plurality of small batch feeders such as in U.S. Pat. No. 3,127,033. Such an approach appears to be quite limited as to throughput because of the small size of the inlets through which batch is fed.
Two types of batch feeders are in widespread commercial use in the glass industry. The first being the reciprocating tray type as shown in U.S. Pat. Nos. 1,916,262 and 3,780,889 and the second being the rotary type as shown in U.S. Pat. No. 2,829,784. The reciprocating tray type feeder inherently tends to form a series of ridges extending laterally across the batch blanket. However, these ridges are not as steep as would be desired for the sake of enhancing run-off nor do the furrows between the ridges provide a sufficiently free path for run-off. After melting of the batch blanket has progressed substantially, the ridges typically become separated into floating masses known as "logs." However, break-up of the batch blanket does not occur as early as would be desired. The rotary type feeder produces a nearly level batch blanket with only a shallow treadmark on the surface produced by the rotary feeder blades. Hence, the rotary type feeder is particularly characterized by poor run-off.
It appears that the prior art has not fully appreciated nor used the advantages attendant to enhancing run-off of melted material from a batch blanket.
SUMMARY OF THE INVENTION
It has now been found that a major rate determining step of the glass melting process is the ablation of the batch layer, i.e., the run-off of a thin melted layer to expose underlying unmelted batch. Although surface area available for heat transfer to the batch is an important parameter for determining the rate of melting, it has now been discovered, quite surprisingly, that the area available for run-off is even more important. Thus, the present invention is directed to improving the run-off of liquid material from the batch layer so as to improve the overall melting rate. This is accomplished by increasing the amount of sloped area on the upper surface of the batch blanket. Moreover, this contouring of the batch blanket is achieved in the preferred embodiments of the present invention without increasing the thickness of portions of the batch layer and without requiring a reduction in the mass throughput of a glass melting furnace. This is accomplished by providing compacted, sloped surfaces on the batch layer. The most beneficial ablation enhancing affects have been found when the batch blanket is provided not only with a large proportion of sloped run-off areas, but also with a well distributed number of run-off openings extending substantially through the thickness of the batch blanket and into communication with the underlying molten glass. These run-off openings prevent a slow-down of the ablation affect due to the areas between the run-off slopes becoming filled with the melted liquid.
Ablation enhancement per se is the subject matter of co-pending U.S. patent application Ser. No. 155,802, filed on June 2, 1980, by Joseph J. Hammel and entitled "Method of Improving Glass Melting by Ablation Enhancement." The present invention relates particularly to ablation enhancement by imparting toroidal shapes to the batch materials being fed to a glass melting furnace. Since the primary purpose for these toroids of batch is to provide sloping surfaces for run-off rather than surface area, the toroids should be in the form of aggregates sufficiently large to maintain their structural integrity for an appreciable time within the furnace. Therefore, the toroidal aggregates are preferably considerably larger than the units of agglomerated batch previously employed in the prior art (e.g., pellets and briquettes). On the other hand, the shaped aggregate should not be so large as to result in unmelted chunks traveling downstream into the furnace beyond the usual batch melting zone. Therefore, it would be preferred that the shaped aggregates have a height no greater than the usual thickness of a batch blanket.
Conventional glass batch formulas, when slightly wetted with water or caustic soda solutions, can readily be molded to toroidal shapes having sufficient structural integrity. The wetted batch may be tamped slightly into a mold, or conventional briquetting or tabletting processes on an enlarged scale may be employed. In any case, the batch in the shaped aggregate will be compacted relative to a loosely fed batch blanket. The shaped aggregates may be fed into the melting furnace with a distribution that provides substantially an equivalent mass density of batch in the melting zone to that conventionally provided by the batch blanket. At the same time, interstices between the shaped aggregates provide run-off openings to the underlying body of molten glass.
THE DRAWINGS
FIG. 1 is a schematic, cross-sectional side view of the inlet end of a continuous, flat glass melting furnace, showing a batch layer as an array of toroids in accordance with the present invention.
FIG. 2 is an enlarged cross-sectional view of the toroid shaped batch layer of FIG. 1.
FIG. 3 is a cross-sectional view of an alternate form of a toroidal batch aggregate.
FIG. 4 is yet another alternate form of toroidal shaping of a batch layer contemplated by the present invention.
FIG. 5 is a plan view of an array of torroidal batch aggregates as in FIGS. 1 and 2.
DETAILED DESCRIPTION
The insulating affect of glass batch has been demonstrated by melting a hemisphere of batch having a six inch (15.24 centimeter) radius in which thermocouples were implanted at various distances from the surface. Melting the hemisphere in a furnace at 2800° F. (1540° C.) produced a surface layer of foam, beneath which active melting appeared to take place in a 0.15 inch (3.8 millimeter) thick layer at the surface of the hemisphere. The temperature at the outside of this thin melting layer was 2050° F. (1120° C.) and on the inner side was 1500° F. (825° C.). An additional inch (2.54 centimeters) below the melting layer, the batch temperature was observed to be approximately 100° F. (38° C.), which was only slightly above room temperature. Dissection of partly melted hemispheres shows that a major portion of the batch in the interior remains unaffected, even though melting has taken place at the surface.
The following experiment was conducted to observe the influence of shape on the melting rate of batch. Glass batch of a standard commercial formulation was molded into five shapes: slab, cone, hemisphere, scalloped slab, and toroid. So that each of the shapes would represent a modification of a given area of a batch blanket, each of the shapes was proportioned so as to yield essentially the same base area and volume (and therefore mass) based on the base area and volume of a six inch (15.24 centimeter) radius hemisphere. Surface area varied from one shape to another. The precise dimensions are set forth in Table 1. The shapes were molded by tamping the batch, which was wetted with about 7 to 8 weight percent water, into a mold so as to compact the batch to a density of about 90 pounds per cubic foot (1.43 kg/liter) compared to a loose batch density of about 70 to 75 pounds per cubic foot (1.11 to 1.19 kg/liter). The slab at its base measuring 10.6 by 10.6 inches (27.0 by 27.0 centimeters) and 4 inches (10.16 cm) in height. The cone had a base diameter of 12 inches (30.5 cm) and a height of 12 inches (30.5 cm). The hemisphere had a radius of six inches (15.24 cm). The scalloped slab had a base of 15.45 by 7.33 inches (39.2 by 18.6 cm) and a height of 2 inches (5.08 cm) above which extended three continguous, axially bisected cylinders, each having a radius of 2.57 inches (6.53 cm) and a length of 7.33 inches (18.6 cm). The toroid had an outer base diameter of 12.2 inches (31.0 cm) and an inner opening 1.9 inches (4.8 cm) in diameter at the base. The upper portion of the toroid was hemispherically rounded with a radius of 2.57 inches (6.53 cm) and rested on a base portion 2 inches (5.08) in height which was rectangular in cross-section like those shown in FIG. 2. Each of these shapes was placed into a furnace at 2800° F. (1540° C.) and the time required to render the batch entirely to liquid was measured. Liquefied batch running off from the shapes was permitted to drain from the vicinity of the shape. The results are shown in Table I in the order of increasing melting rates.
TABLE I______________________________________ Surface/ Volume Base Volume Surface Ratio Melting Area in.sup.3 Area in.sup.-1 TimeShape in.sup.2 (cm.sup.2) (liters) in.sup.2 (cm.sup.2) (cm.sup.-1) min.______________________________________Slab 112.9 451.6 282.9 0.62 37.3 (728.2) (7.40) (1825) (0.25)Cone 113.1 452.4 252.9 0.56 36.3 (729.5) (7.42) (1631) (0.22)Hemisphere 113.1 452.4 226.2 0.5 35.8 (729.5) (7.42) (1459) (0.20)Scalloped 113.25 454.6 330.9 0.73 34.5slab (730.5) (7.46) (2134) (0.29)Toroid 116.9 457.9 267.4 0.59 27.3 (754.0) (7.51) (1725) (0.23)______________________________________
It can be seen that, contrary to what might be expected, the melting rate did not correspond to surface area of the shapes. For example, the slab shape, in spite of having the second largest surface area, exhibited the slowest melting time. On the other hand, the toroid, with only the third largest surface area, exhibited a melting time significantly shorter than any of the other shapes. It is believed that these results may be explained in terms of relative run-off areas provided by the shapes, with the superior performance of the toroid apparently being due to the fact that run-off from a toroid shape occurs in two directions: toward the central opening, and down the outer periphery. If a conventional batch blanket most closely resembles the slab shape, it may be concluded that contouring the batch blanket to more closely resemble any of the other shapes, in particular the toroid, would result in improvements in melting rate comparable to those shown in Table I.
The most straightforward adaptation of the present invention to commercial glass melting processes is to form aggregates of glass batch to a toroidal shape at a batch preparation station separate from the melting furnace. The shaping may be carried out simply by pressing the wetted batch into a mold, but for full-scale production, it is preferred that a briquetting type process be used such as those shown in U.S. Pat. Nos. 2,214,191; 2,578,110; 3,233,022; and 4,023,976. Unlike these prior art briquetting methods, wherein the object is to produce a large number of small agglomerates having a cumulative large surface area, the preferred mode of the present invention entails the production of relatively massive aggregates having sloped surfaces which will have a relatively extended life span within a melting furnace. It would be preferred that the aggregates present sloped surfaces at a substantial elevation above the surface of the molten glass in a melting furnace for at least one half of the residence time of the last melted increment of batch. For example, batch is typically reduced to liquid in a large commercial flat glass furnace in a maximum time on the order of about thirty minutes, in which case it would be preferred that the sloped run-off surfaces of the aggregates persist for at least fifteen minutes in such a furnace. Thus, the toroids of the present invention will preferably be considerably larger in size than the briquettes or pellets of glass batch which have been previously proposed. It is preferred that the aggregates of the present invention each have a base area of which the minor dimension is at least 10 centimeters, up to about 25 centimeters. A similar range is preferred for the height of each aggregate. Since the lower portion of each aggregate will be submerged beneath the surface of the molten glass in the furnace, the shape of the lower portion is not critical for the purposes of the present invention and may be flat or irregular, irrespective of the shape of the upper portion of the aggregate.
It has been found that glass batch moistened with water to a moisture content of about five percent to ten percent by weight, preferably seven to eight percent, has sufficient self-adhesion to be molded into toroids having sufficient structural integrity for the purposes of the present invention. Instead of, or in addition to, some or all of the water, other binding aids such as caustic soda solution or sodium silicate solution may be employed. Also, molding may be aided by the use of known organic binding agents. Molding glass batch to a self supporting shape entails compacting at least a surface portion of the shape. Sufficient compaction, expressed as percentage increase of density, is generally in the range of ten percent to forty percent, preferably fifteen percent to thirty percent. In some cases it may be sufficient for the compaction to take place in surface portions only of the agglomerate (e.g., the first one to five centimeters) since a compacted outer shell may contain a non-compacted quantity of batch in the interior of the aggregate.
The data herein regarding compaction and moisture content pertain particularly to the following flat glass batch formula which is also the formula employed in the examples of Table I:
TABLE II______________________________________Ingredient Parts by Weight______________________________________Sand 1,000Soda Ash 313.5Limestone 84Dolomite 242Salt Cake 14Rouge 0.75Coal 0.75______________________________________
The above batch formula is a typical commercial flat glass batch formula, but the principles of the present invention are applicable to the many possible variations in batch formulas, not only for flat glass, but also for fiber glass, container glass, silicate melting, and others with only slight, if any, variations from the specific examples set forth herein. By following the general teachings of the present invention, producing a structurally stable aggregate of any conventional glass batch formula will be well within the ordinary skill of the person in the art.
The shaped aggregates may be fed to a melting furnace by means of a reciprocating tray type feeder with a plurality of the aggregates side by side so as to form an array of aggregates floating on the pool of molten glass whose appearance would resemble those in FIGS. 1 and 2.
Another embodiment of the invention may entail shaping of the glass batch aggregates at the inlet to the melting furnace itself. This could be effected by means of a reciprocating press type molding apparatus or a continuous rotating mold provided with a plurality of mold concavities about its periphery. Depending upon the compactability of the wetted batch formula, the downward pressure of the rotating mold acting against the buoyant force of the batch may be sufficient to compact the batch and form the aggregates. In other cases, the pressure required for compaction may be produced between a mold and a stationary rigid member between which the batch may be pinched. The rotating mold may also serve as a batch pusher to feed the contoured batch blanket into the main portion of the furnace in the same manner as a rotary type feeder.
FIG. 1 shows an inlet end of a typical continuous flat glass melting furnace 10 having an inlet opening 11 and containing a pool of molten glass 12. Because materials are shown being fed through the inlet opening 11 as a series of molded aggregates in the shape of toroids 15 which form an array that may be several toroids wide and extends into the main portion of the furnace. In FIG. 1 the toroids are depicted as extending beyond burner port 14, which is the first of a series of burner ports (typically 4 to 8 on each side), although the extent of the batch layer into the furnace will vary from one furnace to another.
An enlarged cross-sectional view of the toroidal aggregates 15 is shown in FIG. 2, where it may be seen that the toroids may have flat bottoms. The more classical "doughnut" shaped toroid such as the molded aggregate 16 in FIG. 3 may also be employed and it should be understood that both types of shapes, as well as other variations of the basic toroid, are intended to be encompassed by the terms "toroid" and "toroidal" as employed herein. It is contemplated that the specific shapes of FIGS. 2 and 3 would be molded at a preliminary station and then deposited onto the pool of glass 12 within the furnace. As depicted in FIG. 5, the toroids would be fed several abreast so that the batch layer is in the form of an array of the toroids which may be advanced incrementally into the furnace by conventional pushing means.
In another embodiment of the invention, the toroidal shapes may be imparted to a batch layer after the batch layer has been deposited onto the molten glass at the inlet end of the furnace. Mold means may be employed at the inlet periodically to impress a pattern of toroidally shaped mounds and depressions such as that shown in FIG. 4. There, a batch layer 17 floating on a surface of molten glass 12 has had an array of toroid shaped mounds 18 separated by depressions 19 imparted thereto. Initially, discrete toroids may not be formed, but early in the melting process the thin batch portions 20 at the bottom of the depressions 19 as well as the thin portions 21 at the bottom of the central opening of each toroid will melt away, providing a large number of well distributed openings through which run-off from the remainder of the shaped batch layer may pass into the underlying pool of molten glass.
The specific embodiments and examples set forth herein have been disclosed for the sake of illustration and to describe the best modes for practice of the invention, but it should be apparent that other variations and modifications known to those skilled in the art may be applied to the present invention without departing from the spirit and scope of the invention as set forth in the claims.
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The rate of melting glass batch to a liquid state is improved by providing sloped surfaces on the batch to enhance run-off of liquid. The slopes are provided by feeding batch as toroidally shaped aggregates.
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FIELD OF INVENTION
[0001] The present invention relates to yarns made of polymeric material for use in industrial fabrics.
DESCRIPTION OF PRIOR ART
[0002] Industrial fabrics, especially papermaking fabrics, are typically but not exclusively made of a woven structure using polymer yarns in the weft and warp direction. To improve the smoothness and the printability of a paper sheet produced on a papermaking fabric it is desirable to increase the smoothness and the contact area of the paper contacting surface of the papermaking fabric. Especially for high speed applications it is further desirable to increase the smoothness of the wear side of the papermaking fabric in order to improve the aerodynamic performance of the fabric.
[0003] The smoothness of the paper contacting surface can be improved by increasing the yarn density resulting in increased manufacturing costs and reduced permeability of the fabric.
[0004] Further the smoothness can be improved by using profiled monofilament yarns having flat surface. When using the flat shaped yarns, e.g. as warp yarns in float weave designs, the flat warp yarns provide greater surface contact area. It has been found that for many applications the gain in contact area by using such flat yarns is not sufficient. Especially for graphic and fine paper grades it would be desirable to bring the weft yarns as well as the warp yarns into the paper contacting surface of the papermaking fabric to increase the contact area and the smoothness of the fabric to a sufficient level.
SUMMARY OF THE INVENTION
[0005] It is the object of the present invention to provide polymer yarns suitable for the use in industrial fabrics with which it is possible to overcome the disadvantages described above.
[0006] It is another object of the invention to provide industrial fabrics overcoming above described disadvantages.
[0007] According to a first aspect of the invention there is provided a yarn for an industrial fabric. Such an industrial fabric will be subjected to a maximum heat set temperature during production. The yarn according to the invention is made from polymeric material. The polymeric material includes a first phase having a melting temperature and a second phase having a melting temperature. According to the invention the melting temperature of the second phase is equal to or less than the maximum heat set temperature and the melting temperature of the first phase is higher than the maximum heat set temperature.
[0008] The idea of the invention is to provide a yarn having the ability for controllable deformation when subjected to mechanical tension and thermal heat, as is the case during heat set treatment for industrial fabrics. The yarn according to the invention is therefore made from a polymeric material including two different phases which have two different melting points wherein the melting temperature of the second phase is equal to or less than the maximum heat set temperature and wherein the melting temperature of the first phase is higher than the maximum heat set temperature.
[0009] The second phase takes over the part that the yarn softens during heat set treatment and the first phase take over the part that the yarn does not melt. Therefore by combining a first and second polymeric phase according to the invention a yarn is provided which softens during the heat set treatment and becomes very deformable without melting.
[0010] If the yarns according to the invention are, e.g., weft yarns of a woven industrial fabric and if the warp yarns of the fabric are made from standard yarn material, during heat set treatment the harder warp yarns can compress the softer and deformable weft yarns resulting in a crimp interchange between the warps and the wefts leading to a reduction of the warp knuckles giving a fabric with enhanced surface smoothness.
[0011] Typical maximum heat set temperatures are in the range of 90° C. to 260° C.
[0012] Further the industrial fabric will be operated on, e.g., a papermaking machine at a maximum operation temperature. Therefore, according to a preferred embodiment of the invention the melting temperature of the second phase is higher than the maximum operating temperature.
[0013] According to a preferred embodiment of the invention the polymeric material is a polymer blend wherein the first phase includes a first polymer component and wherein the second phase includes a second polymer component and wherein the first and the second polymer component are at least substantially immiscible. By blending immiscible polymer compounds most of the properties, e.g., the melting temperature of each polymer compound, will be maintained substantially.
[0014] It is further possible that the first and the second phase are of the same material and differ in their state of aggregation.
[0015] Depending on the application the maximum operation temperature for an industrial fabric is less than 90° C. or less 120° C. For papermaking fabrics maximum heat set temperatures are in the ranges as follows:
[0016] Forming fabrics: 170° C. to 190° C., typically 180° C. to 185° C.
[0017] Press fabrics: 160° C. to 185° C., typically 160° C. to 165° C.
[0018] Dryer fabrics: 180° C. to 220° C., typically 190° C.
[0019] Therefore the melting temperature of the second phase/second polymer component is in the range of 120° C. to 220° C., preferably in the range of 160° C. to 220° C.
[0020] By way of example:
[0021] A fabric will be subjected to a heat set treatment with a maximum temperature of 190° C. and will be operated at a maximum operation temperature of 120° C. Therefore the melting temperature of the second phase of a yarn according to the invention must be lower than 190° C. and higher than 120° C. The melting temperature of the first phase of this yarn is more than 190° C.
[0022] According to a further preferred embodiment of the invention the melting temperature of the second phase/second polymer component is at least 30° C. lower than the melting temperature of the first phase/first polymer component.
[0023] According to a further preferred embodiment of the invention the melting temperature of the second phase/second polymer component is at least 80° C. lower than the melting temperature of the first phase/first polymer component.
[0024] According to another preferred embodiment of the invention the melting temperature of the second phase/second polymer component is typically between 100° C. and 110° C. lower than the melting temperature of the first phase/first polymer component.
[0025] Further the first component includes any of the following either alone or blended: homopolymers and copolymers of the polyesters, homopolymers and copolymers of polyamides, polyphenylene sulphide (PPS).
[0026] Most preferably the first component includes polyethylene terephthalate (PET).
[0027] In addition the second component includes any of the following either alone or blended: polyolefins, polyamides, fluoropolymers.
[0028] Most preferably the second component includes Polyolefins.
[0029] It has been found by the applicant that yarns according to the invention showing the best deformability at the heat set temperature for which they are designed is a blend including between 51% and 99% by weight, preferably between 60% and 95% by weight, of the first component and between 49% and 1% by weight, preferably between 5% and 40% by weight, of the second component.
[0030] To allow the polymer blend to be processed it may be necessary to incorporate at least one suitable compatibilizer. Without a suitable compatibilizer, e.g., mechanical properties, e.g. toughness of the yarn produced can be reduced. Further for immiscible polymer blends the so called “die swell” during extrusion can increase which effects the controllability of the extruded yarn diameter. Therefore according to a further preferred embodiment the polymer blend includes at least one suitable compatibilizer.
[0031] It has been found by the applicant the best results in regard to processability can be achieved if the at least one compatibilizer is included in an amount of 0.01% to 10% by weight, preferably in an amount of 0.1 to 5% by weight.
[0032] There are different types of compatibilizer suitable for the polymer blend according to the invention. According to a preferred embodiment of the invention at least one compatibilizer is a physical compatibilizer. A physical compatibilizer is based on the principle that components of the compatibilizer are miscible which each component/phase of the blend. Thus the compatibilizer is acting as a polymeric surfactant.
[0033] According to a further preferred embodiment of the invention the physical compatibilizer is any of the following: Ethylene Methyl Acrylate Copolymer (EMA), Ethylene. Butyl Acrylate Copolymer (EBA). By way of example the blend includes the polymer components polyethylene (PE) and PET and the compatibilizer EMA. In this case the ethylene component of the compatibilizer is miscible with PE and the methacrylate component of the compatibilizer is miscible with PET.
[0034] A suitable compatibilizer also can be a reactive compatibilizer. This method of compatibilization relies e.g. on the chemical reaction between the functional group that is grafted onto the PE and the end groups of the PET. This results in the in-situ formation of a PET/PE copolymer which then acts as a physical compatibilizer for the blend.
[0035] The suitable reactive compatibilizer can be any of the following: Ethylene-g- Maleic Anhydride Copolymers, Ethylene-g- Glycidal Methacrylate.
[0036] Further the polymer blend can include at least one suitable stabilizer. A stabilizer for example is added to design yarns with the ability to withstand severe conditions as high temperature and/or high humidity. According to one preferred embodiment of the present invention the at least one stabilizer is a hydrolysis stabilizer. Hydrolysis stabilizers are added to the blend to generate yarns for the use under high humidity conditions.
[0037] The hydrolysis stabilizer can be a carbodiimide compound either monomeric, polymeric or a combination.
[0038] According to a further preferred embodiment of the invention the at least one stabilizer can be an anti-oxidation stabilizer. Anti-oxidation stabilizers are added to the blend to generate yarns for the use under high temperature conditions.
[0039] It has been found by the applicant that the best results in retaining the properties of the blend can be achieved if the at least one stabilizer is included in an amount of 0.1% to 10% by weight, preferably in an amount of 0.5 to 5% by weight.
[0040] According to a second aspect of the present invention there is provided a yarn for use in an industrial fabric, preferably a woven fabric, which has a tensile elongation of at least 10% at 1.75 grams per denier (gpd). Surprisingly applicant found out that especially a woven fabric at least in part comprising yarns having a tensile elongation of at least 10% at 1.75 grams per denier has improved properties in regard to surface smoothness and wear resistance.
[0041] Preferably, the tensile elongation at 1.75 grams per denier is between 15% and 30%.
[0042] According to a preferred embodiment of the present invention the yarn has a elongation at yield point 1 which is greater than 5% and/or an elongation at yield point 2 which is greater than 20%.
[0043] Further the yarn according to the invention preferably is a monofilament yarn but also can be a multifilament yarn.
[0044] The yarn according to the invention has a diameter in the range of 0.20 mm to 2.0 mm, preferable in the range of 0.4 mm to 1.0 mm. These diameters are suitable for most of the different types of papermakers' fabrics.
[0045] According to a further embodiment of the invention the shape of the yarn is round or profiled, e.g., with chamfered edges.
[0046] It has been found by the applicant that an industrial fabric comprising a set of weft yarns and a set of warp yarns, wherein the warp yarns and the weft yarns are interwoven to form a specific weave design, and wherein tension has been applied to the weft yarns or the warp yarns during a heat set treatment, has improved surface smoothness and wear resistance if at least one of the yarns of the fabric have not been tensioned during heat set treatment has an enhanced crimp level of at least 0.5% compared to the corresponding yarn of a reference fabric, wherein the reference fabric has the same weave design as the fabric, wherein all weft and warp yarns of the reference fabric have the same diameter as the weft and warp yarns of the fabric, wherein the reference fabric has been manufactured under the same conditions as the fabric, and wherein the corresponding not tensioned yarn of the reference fabric is made from PET based polymeric material.
[0047] By providing a fabric comprising yarns which have not been tensioned during heat set treatment and which have after heat set treatment an enhanced crimp level of at least 0.5% compared to yarns made from PET having the same position in a reference fabric as the yarns in the fabric, wherein the reference fabric being identical in all features and in manufacturing as the fabric according to the invention except that the similar/corresponding yarns are made from PET, the non tensioned yarns and the tensioned yarns of the fabric lie more together in one common plane of the fabric compared to the yarns in the reference fabric. This leads to a fabric according to the invention having enhanced smoothness, less tendency of wire marking and improved wear resistance.
[0048] The crimp level is calculated with the following formula:
(length along the crimped line of the yarn−length along the straight line of the yarn)/length along the straight line of the yarn*100=crimp level in %
[0049] By way of example for a given yarn the length along the crimped line of the yarn is 12 cm and the length along the straight line is 10 cm the crimp level is (12 cm-10 cm)/10 cm*100=20%.
[0050] According to a preferred embodiment of this aspect of the invention at least some of the yarns not being tensioned during heat set treatment have the enhanced crimp level compared to the corresponding yarns in the reference fabric.
[0051] According to most preferred embodiment of this aspect of the invention all of the yarns to which no tension has been applied to during heat set treatment have the enhanced crimp level.
[0052] Preferably the non-tensioned yarns are weft yarns.
[0053] According to a further preferred embodiment of the invention the enhanced level of crimp is at least 1.0%, preferably at least 1.5%, most preferably in the range of 1.5% to 2.5%. It has been found that with increasing crimp level the smoothness of the fabric increases. Further it has been found that an optimum in smoothness is achieved if the crimp level of the non-tensioned yarns during heat set treatment is in the range of 1.5% and 2.5%.
[0054] Typical heat set conditions are:
tension selected from the range of 1 kN/m to 6 kN/m, temperature with a maximum temperature selected from the range of 90° C. to 260° C.
[0057] Further it has been found by the applicant that the paper contacting surface has an enhanced smoothness over the paper contacting surfaces of prior art papermaking fabrics leading to less sheet marking if the ratio of crimp level of the warp yarns to the crimp level of the weft yarns is as low as possible.
[0058] Therefore, according to another aspect of the invention there is provided an industrial fabric having a set of weft yarns and a set of warp yarns. The warp yarns and the weft yarns are interwoven with each other and have a crimp level after heat set treatment. During heat set treatment a tension in the range of 1 kN/m to 6 kN/m, preferably 1.5 kN/m to 5 kN/m and a temperature in the range of 90° C. to 260° C., preferably 160° C. to 220° C. has been applied to the warp yarns. According to the invention at least one warp yarn and at least one weft yarn have a crimp level ratio which is less than 4, wherein the crimp level for each yarn is the difference of the length along the crimped line of the yarn and the length along the straight line of the yarn divided through the length along the straight line of the yarn.
[0059] The second aspect of the invention will be explained by way of example as follows:
[0060] During heat set treatment, tension and temperature are applied to the warp yarns. At least some of the weft yarns are made from a material which softens at the maximum heat set temperature and therefore is very deformable at the maximum heat set temperature. Further the warp yarns are made from a material which softens less than the weft yarns at the maximum heat set temperature. The fact that the weft yarns are made from the material which softens more during heat set treatment than the warp yarns allows the harder warp yarns to compress the softer weft yarns reducing the warp knuckles leading to a smoother fabric.
[0061] Based on the discussion set forth below it is therefore desirable if the ratio of the crimp level of at least one warp yarn to the crimp level of at least one weft yarn is less than 3.5, preferably less than 3.0, most preferably less than 2.
[0062] According to a third aspect of the invention there is provided an industrial fabric including at least in part yarns made from a polymeric material, wherein the industrial fabric has been subjected to a heat set temperature during production, wherein the polymeric material includes a first phase and a second phase, and wherein the melting temperature of the second phase is equal or less than the heat set temperature and wherein the melting temperature of the first phase is higher than the heat set temperature.
[0063] According to a further preferred embodiment of the invention the yarns made of polymeric material having two phases are weft and/or warp yarns.
[0064] Further, it is desirable if the industrial fabric is a papermaking fabric, preferably a forming or a dryer fabric.
[0065] In the case of a dryer fabric the dryer fabric has an air permeability in the range from 50 to 200 cfm, preferably in the range from 75 to 150 cfm.
[0066] According to a preferred embodiment in regard to a specific weave design of the industrial fabric the set of weft yarns comprises first and second weft yarns, wherein the first weft yarns are disposed over the second weft yarns and wherein the warp yarns weave over two consecutive first weft yarns before weaving under one second weft yarn. It has been found by the applicant that a weave design according to this embodiment has improved surface smoothness.
[0067] According to an embodiment of the above mentioned weave design the first weft yarns are in offset position relative to the second weft yarns.
[0068] According to another embodiment of the weave design it is foreseen that adjacent warp yarns weave in offset position relative to each other over the two consecutive first weft yarns, wherein the offset position of the adjacent warp yarns preferably is at least one first weft yarn.
[0069] Preferably, the weave design comprise per weave repeat four warp yarns and four first and four second weft yarns.
[0070] The following examples are intended to illustrate the invention, not to limit it.
TABLE 1 Composition Reference Sample 1 Sample 2 Sample 3 Sample 4 Component 1 100% 98% 95% 91% 87.3% PET PET PET PET PET Component 2 — 2% PE 5% PE 5% PE 5% PE Additive 1 — — — 1% Anti- 0.5% Anti-Oxidant Oxidant Additive 2 — — — 3% Compatibilizer 3% Compatibilizer Additive 3 — — — — 1.2% Hydrolysis stabilizer Melting temp. phase 1 [° C.] 253 253 253 253 253 Melting temp. phase 2 [° C.] — 120 120 120 120 Tenacity [gpd] 2.9 3.1 2.9 2.8 3.1 Elongation at break [%] 45 47 46 54 45 Young's Modulus [gpd] 72 71 70 63 60 Shrinkage [%] 15 15.8 17 12 11 Strength retained [%] after 69 63 38 30 85 hydrolysis at 140° C., 24 hours Strength retained [%] after 46 44 51 54 80 dry heat at 204° C., 24 hours
[0071] All the different components are added in % by weight.
[0072] Table 1 is showing a comparison between a standard PET monofilament yarn (Reference) and monofilament yarns according to the invention (Sample 1 to Sample 4) having the same yarn diameter (0.7 mm) as the reference yarn.
[0073] As can be seen in Table 1, the yarns of samples 1 to 4 have two melting temperatures. A melting temperature of the first phase which is at 253° C. and a melting temperature of 120° C. of the second phase. Therefore the yarn according to the invention has a melting temperature (120° C.) which is in the temperature range of typical heat set treatments (90° C. to 220° C.) and a melting temperature which is higher than the heat set temperature.
[0074] Sample 1 to 4 are made from a polymer blend including the polymer components PET and PE, wherein the first phase is formed by the PET polymer component and the second phase is formed by the PE polymer component. PET and PE are immiscible polymers and therefore generate a blend with two phases.
[0075] As cain be seen especially sample 1, 2 and 4 have approximately the same mechanical properties as the reference sample. Sample 1 has the same degradation resistance as the reference sample.
[0076] To improve processability samples 3 and 4 include 3% of a compatibilizer.
[0077] To improve the resistance to dry heat treatment, sample 3 further includes 1% of an anti-oxidant stabilizer. As can be seen the strength retained after dry heat treatment is increased to 54%.
[0078] To improve hydrolysis resistance sample 4 further includes a hydrolysis stabilizer in an amount of 1.2%. As can be seen from Table 1 sample 4 has the best dry heat and wet heat resistance behaviour.
BRIEF DESCRIPTION OF THE DRAWINGS
[0079] The invention shall be further illustrated with the following figures, wherein
[0080] FIGS. 1 ( a ) and 1 ( b ) show a comparison between the paper contacting surface of a dryer fabric made from standard yarn material and a dryer fabric made from yarn material according to the invention,
[0081] FIGS. 2 ( a ) and 2 ( b ) show the difference in contact area between the dryer fabric according to the invention and a standard dryer fabric,
[0082] FIGS. 3 ( a ) and 3 ( b ) show the difference in crimp level between the dryer fabric according to the invention and an standard dryer fabric, and
[0083] FIG. 4 shows the weave design of fabrics 1 and 10 in warp yarn direction.
DETAILED DESCRIPTION OF THE INVENTION
[0084] FIGS. 1 ( a ) and 1 ( b ) show photographs of the paper contacting surface of a dryer fabric 1 made from standard yarn material and a photograph of the paper contacting surface of a dryer fabric 10 made from yarn material according to the invention.
[0085] It has to be noted that both fabrics 1 , 10 have the same weave design and that the weft and the warp yarns of both fabrics have the same diameter. Further both fabrics are manufactured identically at least in terms of the heat set treatment which had been performed applying a tension in the range of 1.5 kN/m to 5 kN/m to the warp yarns with a temperature in the range of 170° C. to 220° C.
[0086] FIG. 1 ( a ) shows the paper contacting surface 2 of the fabric 1 having warp 3 and weft 4 yarns made from 100% PET.
[0087] FIG. 1 ( b ) shows the paper contacting surface 11 of the fabric 10 having warp yarns 12 made from 100% PET and having weft yarns 13 made from a PET-PE polymer blend according to the invention.
[0088] As can be seen in FIG. 1 ( a ), the weft yarns 4 of the fabric 1 substantially extend in a straight line having a low crimp level. Measurements have shown a crimp level in the 4% range. In contrast thereto the warp yarns 3 have a high crimp level which is approximately 19%. Therefore the paper contacting surface of the dryer fabric 1 only has a contact area 5 of the dryer fabric 10 of 22% (grey coloured) as shown in FIG. further 2 ( a ). Further, the crimp level ratio of warp yarn to weft yarn is 4.75.
[0089] As can be seen in FIG. 1 ( b ), the weft yarns 13 of the fabric 10 extend in a crimped line having a high crimp level compared with the crimp level of the weft yarns 4 according to FIG. 1 a. Measurement have shown a crimp level of the wefts 13 is in the 5.5% range. Further, the warp yarns 12 have a lower crimp level than the warp yarns 3 of the dryer fabric 1 . The crimp level of the warp yarns 12 is approximately 10%. Therefore, the paper contacting surface of the dryer fabric 10 has an enhanced contact area 14 of 30% (grey coloured) as shown in FIG. 2 ( b ) compared to the contact area 5 of the dryer fabric 1 which is 22% (grey coloured) as shown in FIG. 2 ( a ). According to the invention, the crimp level ratio of warp yarn to weft yarn is 1.8.
[0090] Figures (a) and (b) show the difference in crimp level between a weft yarn 13 of the dryer fabric 10 according to the invention and a weft yarn 4 of the standard dryer fabric 1 .
[0091] A weft yarn of a fabric according to the invention can have a crimp level in the range of 5.0% to 7.0%, typically in the range of 5.5% to 6.5%, depending on the specific weave design, the yarn diameter and the heat set conditions.
[0092] The weft yarns 13 of the fabric 10 has a crimp level of 6.0%.
[0093] A weft yarn of a fabric known in the art can have a crimp level in the range of 3.5% to 5.5%, typically in the range of 4.0% to 5.0%, depending on the specific weave design, the yarn diameter and the heat set conditions.
[0094] The weft yarns 4 of the fabric 1 has a crimp level of 4.0%.
[0095] For the same weave design and the same manufacturing conditions the weft yarns of a fabric according to the invention has an enhanced crimp level of at least 0.5%, preferably at least 1.0%, most preferably at least 1.5% and preferred in the range of 1.5% to 2.5%.
[0096] In the concrete embodiment of FIGS. 1 ( a ) and 1 ( b ), the difference in crimp level between fabric 10 and 1 is 2%.
[0097] FIG. 4 shows the weave design of fabrics 1 and 10 in warp yarn direction. For further discussions the weave design will be discussed by reference numbers of fabric 10 .
[0098] Fabric 10 comprises first weft yarns 13 a, 13 b, 13 c, 13 d and second weft yarns 13 e, 13 f, 13 g and 13 h. The first weft yarns 13 a, 13 b, 13 c, 13 d are disposed over the second weft yarns 13 e, 13 f, 13 g and 13 h. Further first weft yarns 13 a, 13 b, 13 c, 13 d are in offset position relative to second weft yarns 13 e, 13 f, 13 g and 13 h.
[0099] As can be seen warp yarns 12 A, 12 B, 12 C and 12 D weave over two consecutive first weft yarns before weaving under one second weft yarn.
[0100] By way of example warp yarn 12 B (dashed line) weaves over consecutive first weft yarns 13 a and 13 b before weaving under second weft yarn 13 h.
[0101] In addition, adjacent warp yarns weave in offset position relative to each other over the two consecutive first weft yarns, wherein the offset position is defined by one first weft yarn.
[0102] By way of example warp yarn 12 B weaves over first weft yarns 13 a and 13 b, wherein adjacent warp yarn 12 C (dash dotted line) weaves over first weft yarns 13 b and 13 c. Therefore the offset between warp yarn 12 B and warp yarn 12 C is defined by one first weft yarn.
[0103] As can be seen the weave repeat comprises four warp yarns 12 A to 12 D and four first weft yarns 13 a, 13 b, 13 c, 13 d and four second weft yarns 13 e, 13 f, 13 g 13 h.
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Yarn for an industrial fabric which will be subjected to a heat set temperature during production. The yarn is made from polymeric material, the polymeric material includes a first phase and a second phase, wherein the melting temperature of the second phase is equal or less than the heat set temperature and wherein the melting temperature of the first phase is higher than the heat set temperature. Also provided are industrial fabrics with enhanced smoothness.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-137150 filed on May 26, 2008, the entire contents of which are incorporated herein by reference.
FIELD
[0002] The embodiments discussed herein are related to a method and an apparatus for rework soldering. For example, a method and apparatus for performing reflow soldering or rework soldering.
BACKGROUND
[0003] Newly developed high performance LSIs (Large Scale Integrated Circuit) using, for example, BGA (Ball Grid Array) are widely used by communication devices and information devices. Electric connection failure with respect to a printed circuit board on which a BGA electronic component is mounted, is in many cases, found for the first time during a testing phase after the BGA electronic component is mounted on the printed circuit board. Since the printed circuit boards are relatively expensive, a reworking (replacing) operation is performed on the BGA electronic component for resolving the connection failure.
[0004] In recent years, lead free solder has been promoted in view of environmental protection. Due to the transition from tin/lead eutectic solder to lead free solder, it is becoming difficult to perform rework soldering where solder bumps of a BGA electronic component are thermally melted for reworking. This is because the melting point of lead free solder (for example, approximately 217° C.) is higher than the melting point of tin/lead eutectic solder (approximately 183° C.).
[0005] Furthermore, although increase in the size of electronic components and decrease of space between electronic components (e.g., space no greater than 2 mm) are progressing due to demands for more functions to be provided by an electronic apparatus, improvement of heat resistance of the electronic apparatus is unlikely. Therefore, controlling the temperature at spaces between electronic components is one important aspect. In one example of controlling the temperature in a rework soldering process, the temperature of the electronic component to be replaced is set to be no less than the minimum soldering temperature (e.g., 230° C.) and the temperature of the component (peripheral component) which is not to be replaced is set to be no greater than the heat resistance temperature (e.g., 170° C.) of the peripheral component.
[0006] FIG. 1 illustrates a side view of a rework soldering apparatus according to a related art example. In FIG. 1 , an electronic component (rework target) 1 and bumps 1 a of the electronic component 1 are heated by blowing warm air from a warm air nozzle 2 positioned above the electronic component 1 (see arrows in FIG. 1 ). Further, the bumps 1 a are also heated via a printed circuit board 3 by blowing warm air from a warm air nozzle 4 positioned below a lower surface of the printed circuit board 3 on which the electronic component 1 is provided.
[0007] A heat insulating material 6 is arranged between the electronic component 1 and another neighboring electronic component (peripheral component) 5 which is not subject to the reworking process, so that the warm air from the warm air nozzle 2 does not blow upon the peripheral component 5 . Further, a heat absorbing material 7 is placed into contact with the peripheral component 5 to prevent the temperatures of the peripheral component 5 and bumps 5 a of the peripheral component 5 from increasing.
[0008] For example, Japanese Laid-Open Patent Publication No. 2003-188527 discloses a method of heating a lower surface of a substrate having an electronic component mounted on an upper surface of the substrate and compulsorily cooling the upper surface with cool air. As another example, Japanese Laid-Open Patent Publication No. 61-56769 discloses a method of arranging thermal insulating materials between a pre-heating part, a main heating part, and a cooling part of a reflow furnace and thermally separating these parts from each other.
[0009] As the space between the electronic component 1 and the peripheral component 5 is further reduced for achieving high density mounting, the radiant heat and the convective heat of the atmosphere and the heat conducted from the printed circuit board 3 may cause the temperature of the bumps 5 a facing the electronic component 1 to surpass the heat resistance temperature of 170° C. when the bumps 1 a facing the peripheral component 5 are heated to a temperature of 230° C.
[0010] Further, enhancing the heat absorbing performance by cooling the heat absorbing material 7 with a cooling agent (e.g., dry ice) and compulsorily reducing the temperature of the bumps 5 a facing the electronic component 1 may cause the temperature of the bumps 1 a facing the peripheral component 5 to decrease and degrade solder joining of the bumps 1 a.
SUMMARY
[0011] According to an aspect of the invention, a method for performing rework soldering for removing an electronic component from a printed circuit board and re-soldering the electronic component to the printed circuit board includes the steps of: positioning a dual structure body including a planar heating member and a cooling member between a rework target and a non-rework target placed on the printed circuit board, the heating member and the cooling member being arranged facing each other with a slight space provided therebetween, the heating member being situated toward the rework target, the cooling member being situated toward the non-rework target; heating the heating member; and cooling the cooling member.
[0012] According to another aspect of the invention, an apparatus for performing rework soldering for removing an electronic component from a printed circuit board and re-soldering the electronic component to the printed circuit board includes: a dual structure body including a planar heating member and a cooling member positioned between a rework target and a non-rework target placed on the printed circuit board, the heating member and the cooling member being arranged facing each other with a slight space provided therebetween, the heating member being situated toward the rework target, the cooling member being situated toward the non-rework target.
[0013] The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
[0014] It is to be understood that both the foregoing generation description and the followed detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 illustrates a side view of a rework soldering apparatus according to a related art example;
[0016] FIG. 2 is a side view for describing an overall configuration of a rework soldering apparatus according to an embodiment of the present invention;
[0017] FIG. 3 is a side view illustrating an embodiment of a rework soldering apparatus;
[0018] FIG. 4 is a cross-sectional view illustrating a part of an embodiment of a rework soldering apparatus;
[0019] FIG. 5 is a perspective view illustrating an embodiment of a heating/reflecting plate;
[0020] FIG. 6 is a perspective view illustrating an embodiment of a cooling plate;
[0021] FIG. 7 is a perspective view illustrating a first embodiment of a dual structure body;
[0022] FIG. 8 is a perspective view illustrating a second embodiment of a dual structure body; and
[0023] FIG. 9 is a table for describing effects of an embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0024] In the following, embodiments of the present invention will be described with reference to the accompanying drawings.
[0025] With the below-described embodiments of the present invention, for example, reflow soldering or rework soldering of an electronic component(s) by using lead free solder can be realized.
<Overall Configuration of Rework Soldering Apparatus>
[0026] FIG. 2 is a side view for describing an overall configuration of a rework soldering apparatus according to an embodiment of the present invention. In FIG. 2 , a BGA electronic component (a component subject to a rework/soldering process, hereinafter also referred to as “rework target”) 11 and a first BGA peripheral component (a component not subject to a rework/soldering process, hereinafter also referred to as “non-rework target”) 12 are positioned on an upper surface of a printed circuit board 10 . A second BGA peripheral component (non-rework target) 13 is positioned on a lower surface of the printed circuit board 10 .
[0027] The electronic component 11 can be selectively (partially) heated from both sides of the printed circuit board 10 by, for example, warm air, infrared (IR) rays, or a heating head.
[0028] On the upper surface of the printed circuit board 10 , a first dual structure 200 is positioned between a heating area for heating the electronic component 11 and a cooling area for cooling the first peripheral component 12 and has an end part contacting the upper surface of the printed circuit board 10 . The first dual structure 200 includes a first heating/reflecting plate (heating member) 14 and a first cooling plate (cooling member) 15 that are arranged facing each other with a slight space provided therebetween. On the lower surface of the printed circuit board 10 , a second dual structure 210 is positioned between the heating area for heating the electronic component 11 and a cooling area for cooling the second peripheral component 13 and has an end part contacting the lower surface of the printed circuit board 10 . The second dual structure 210 includes a second heating/reflecting plate (heating member) 16 and a second cooling plate (cooling member) 17 that are arranged facing each other with a slight space provided therebetween.
[0029] The first and second heating/reflecting plates 14 , 16 are not only configured to heat themselves but also reflect convective heat/radiant heat from the heating area. The first and second cooling plates 15 , 17 are configured to cool themselves. By providing a space (filled with atmospheric air having low thermal conductivity) between the first heating/reflecting plate 14 and the first cooling plate 15 , the first heating/reflecting plate 14 and the first cooling plate 15 can be thermally separated from each other. Likewise, by providing a space (filled with atmospheric air having low thermal conductivity) between the second heating/reflecting plate 16 and the second cooling plate 17 , the second heating/reflecting plate 16 and the second cooling plate 17 can be thermally separated from each other.
[0030] By providing the dual structures in a manner having end parts of the first and second heating reflecting plates 14 , 16 and end parts of the first and second cooling plates 15 , 17 contacting the printed circuit board 10 , convective heat and radiant heat from the atmosphere and thermal conduction from the printed circuit board 10 can be effectively controlled.
<Embodiment of Rework Soldering Apparatus>
[0031] FIG. 3 is a side view illustrating an embodiment of a rework soldering apparatus 1000 . FIG. 4 is a cross-sectional view illustrating a part of the embodiment of the rework soldering apparatus 1000 of FIG. 3 . In FIGS. 3 and 4 , a BGA electronic component (rework target) 21 , BGA peripheral components (non-rework targets) 22 , 23 , and other components are provided on an upper surface of a printed circuit board 20 , and BGA peripheral components (non-rework targets) 25 , 26 and other components are provided on a lower surface of the printed circuit board 20 .
[0032] The electronic component 21 is partially heated by an infrared heater 27 from an upper side of the printed circuit board 20 and is entirely heated by another infrared heater 28 from a lower side of the printed circuit board 20 .
[0033] A dual structure body 300 A is provided on the upper surface of the printed circuit board 20 . The dual structure body 300 A includes a heating/reflecting plate (heating member) 31 and a cooling plate (cooling member) 32 facing each other with a slight space provided therebetween. The dual structure body 300 A has end parts contacting the upper surface of the printed circuit board 20 between a heating area for heating the electronic component 21 and a cooling area for heating the peripheral component 22 . A dual structure body 300 B is provided on the upper surface of the printed circuit board 20 . The dual structure body 300 B includes a heating/reflecting plate (heating member) 33 and a cooling plate (cooling member) 34 facing each other with a slight space provided therebetween. The dual structure body 300 B has end parts contacting the upper surface of the printed circuit board 20 between a heating area for heating the electronic component 21 and a cooling area for cooling the peripheral component 23 .
[0034] Further, a dual structure body 310 A is provided on the lower surface of the printed circuit board 20 . The dual structure body 310 A includes a heating/reflecting plate (heating member) 35 and a cooling plate (cooling member) 36 facing each other with a slight space provided therebetween. The dual structure body 310 A has end parts contacting the lower surface of the printed circuit board 20 between a heating area for heating the electronic component 21 and a cooling area for cooling the peripheral component 25 . A dual structure body 310 B is provided on the lower surface of the printed circuit board 20 . The dual structure body 310 B includes a heating/reflecting plate (heating member) 37 and a cooling plate (cooling member) 38 facing each other with a slight space provided therebetween. The dual structure body 310 B has end parts contacting the lower surface of the printed circuit board 20 between a heating area for heating the electronic component 21 and a cooling area for cooling the peripheral component 26 . With the dual structure bodies 300 A, 300 B, 310 A, 310 B, the spaces between the heating/reflecting plates 31 , 33 , 35 , 37 and the cooling plates 32 , 34 , 36 , 38 are filled with atmospheric air having low heat conductivity.
[0035] Each of the heating/reflecting plates 31 , 33 , 35 , 37 has one end part contacting the surface of the printed circuit board 20 . Temperature sensors 41 , 43 , 45 , 47 are provided at the vicinity of corresponding end parts of the heating/reflecting plates 31 , 33 , 35 , 37 . Likewise, each of the cooling plates 32 , 34 , 36 , 38 has one end part contacting the surface of the printed circuit board 20 . Temperature sensors 42 , 44 , 46 , 48 are provided at the vicinity of corresponding end parts of the cooling plates 32 , 34 , 36 , 38 . The temperatures detected by the temperature sensors 41 - 48 are supplied to a control part 50 .
[0036] Heating parts (e.g., panel heaters) 51 , 53 , 55 , 57 are provided at the other end parts (distal end parts positioned apart from the surface of the printed circuit board 20 ) of the heating/reflecting plates 31 , 33 , 35 , 37 . Further, cooling parts (e.g., heat releasing fins) 52 , 54 , 56 , 58 are provided at the other end parts (distal end parts positioned apart from the surface of the printed circuit board 20 ) of the cooling plates 32 , 34 , 36 , 38 .
[0037] The control part 50 controls the temperatures of the heating parts 51 , 53 , 55 , 57 separately so that each of the temperatures of the heating/reflecting plates 31 , 33 , 35 , 37 detected by the temperature sensors 41 , 43 , 45 , 47 becomes a predetermined temperature (e.g., no less than 230° C.). Further, the control part 50 controls the temperatures of the cooling parts 52 , 54 , 56 , 58 separately so that the temperatures of the cooling plates 32 , 34 , 36 , 38 detected by the temperature sensors 42 , 44 , 46 , 48 become a predetermined temperature (e.g., no greater than 170° C.). It is to be noted that, in a case where heat releasing fins are used as the cooling parts 52 , 54 , 56 , 58 , the control part 50 controls the temperatures of the cooling parts 52 , 54 , 56 , 58 by controlling the amount of refrigerant (e.g., air, water) to be supplied to the heat releasing fins.
[0038] Alternatively, one temperature sensor can be provided on each surface (upper surface and lower surface) of the printed circuit board 20 instead providing all of the temperature sensors 41 - 48 in the vicinity of the upper and lower surfaces of the printed circuit board 20 , to allow the control part 50 to control the temperatures of the heating parts 51 , 53 , 55 , 57 and the cooling parts 52 , 54 , 56 , 58 based on the temperatures detected by the temperature sensor provided on each surface of the printed circuit board 20 .
[0039] A base/driving part 60 , which serves as a base and a driving part, includes supporting members 61 - 66 . The supporting member 61 supports the heating/reflecting plate 31 and the cooling plate 32 . The control part 50 drives the supporting member 61 to move (change position) in direction Z (thickness direction of the printed circuit board 20 ), direction X (horizontal direction in FIG. 3 ), or direction Y (depth direction in FIG. 3 ), to enable the end parts of the heating/reflecting plate 31 and the cooling plate 32 to contact the printed circuit board 20 .
[0040] The supporting member 62 supports the heating/reflecting plate 33 and the cooling plate 34 . The control part 50 drives the supporting member 62 to move (change position) in direction Z, direction X, or direction Y, to enable the end parts of the heating/reflecting plate 33 and the cooling plate 34 to contact the printed circuit board 20 .
[0041] The supporting members 63 , 64 support the printed circuit board 20 . The control part 50 drives the printed circuit board 20 to move (change position) in direction Z, direction X, or direction Y and drives the printed circuit board 20 to rotate around the Z axis of the printed circuit board 20 . Accordingly, flexibility during selection of the electronic component 21 can be improved.
[0042] The supporting member 65 supports the heating/reflecting plate 35 and the cooling plate 36 . The control part 50 drives the supporting member 62 to move (change position) in direction Z, direction X, or direction Y, to enable the end parts of the heating/reflecting plate 35 and the cooling plate 36 to contact the part of the printed circuit board 20 between the electronic component 21 and the peripheral component 25 .
[0043] The supporting member 66 supports the heating/reflecting plate 37 and the cooling plate 38 . The control part 50 drives the supporting member 66 to move (change position) in direction Z, direction X, or direction Y, to enable the end parts of the heating/reflecting plate 37 and the cooling plate 38 to contact the part of the printed circuit board 20 between the electronic component 21 and the peripheral component 26 .
[0044] As illustrated in FIG. 3 , bending of the printed circuit board 20 can be prevented because the printed circuit board 20 is in a fixed position by having its upper and lower surfaces held (sandwiched) by the end parts of the heating/reflecting plates 31 , 33 , 35 , 37 and the end parts of the cooling plates 32 , 34 , 36 , 38 .
<Structure of Heating/Reflecting Plate>
[0045] FIG. 5 is a perspective view illustrating an embodiment of a heating/reflecting plate 70 (corresponding to the heating/reflecting plate 31 , 33 , 35 , 37 ). In FIG. 5 , the heating/reflecting plate 70 includes a metal heating plate 71 and a heating plate holding member 72 . For example, a copper plate having high thermal conductivity (403 W/m·k) and a thickness of approximately 3 mm may be used as the metal heating plate 71 . Further, surface treating using, for example, gold plating may be performed on the metal heating plate 71 for restraining heat radiation and heat absorption of the metal heating plate 71 , to control the radiant heat with respect to, for example, a metal cooling plate 81 (described below) to be a minimum amount. Alternatively, other than using copper for the metal heating plate 71 , aluminum, iron, or stainless steel may also be used.
[0046] A buffering member (shock absorbing member) 73 is provided at an end portion of the metal heating plate 71 contacting the printed circuit board 20 . A resin material having heat resistance and high thermal conductivity or a metal leaf spring may be used as the buffering member 73 . Thus, by having the metal heating plate 71 in firm contact with the printed circuit board 20 with the buffering member 73 , heat flow can be effectively controlled (e.g., effectively separated) and the printed circuit board 20 can be prevented from being damaged.
[0047] The metal heating plate 71 is supported by the heating plate holding member 72 . The heating plate holding member 72 is supported by the supporting members 61 - 66 of the base/driving part 60 . The heating parts 51 , 53 , 55 , 57 are attached to a center part 74 of the heating plate holding member 72 for heating the metal heating plate 71 . It is to be noted that, the metal heating plate 71 and the heating plate holding member 72 may be formed as a united body (integrally formed) and a heat pipe may be used to heat the united body.
<Structure of Cooling Plate>
[0048] FIG. 6 is a perspective view illustrating an embodiment of a cooling plate 80 (corresponding to the cooling plates 32 , 34 , 36 , 38 ). In FIG. 6 , the cooling plate 80 includes a metal cooling plate 81 and a cooling plate holding member 82 . For example, a copper plate having a high thermal conductivity (403 W/m·k) and a thickness of approximately 3 mm may be used as the metal cooling plate 81 . Further, surface treating using, for example, gold plating may be performed on the metal cooling plate 81 for restraining heat radiation to and heat absorption by the metal cooling plate 81 , to thereby control the radiant heat absorbed with respect to, for example, the metal heating plate 71 to be a minimum amount. Alternatively, other than using copper for the metal cooling plate 81 , aluminum, iron, or stainless steel may also be used.
[0049] A buffering member (shock absorbing member) 83 is provided at an end portion of the metal cooling plate 81 contacting the printed circuit board 20 . A resin material having heat resistance and high thermal conductivity or a metal leaf spring may be used as the buffering member 83 . Thus, by having the end portion of the metal cooling plate 81 in firm contact with the printed circuit board 20 with the buffering member 83 , heat flow can be effectively controlled (e.g., effectively separated) and the printed circuit board 20 can be prevented from being damaged.
[0050] The metal cooling plate 81 is supported by the cooling plate holding member 82 . The cooling plate holding member 82 is supported by the supporting members 61 - 66 of the base/driving part 60 . A cooling part (corresponding to the cooling part 52 , 54 , 56 , 58 ) is attached to the cooling plate holding member 82 for cooling the metal cooling plate 81 . It is to be noted that, the metal cooling plate 81 and the cooling plate holding member 82 may be formed as a united body (integrally formed) and a heat pipe may be used to cool the united body.
<First Embodiment of Dual Structure Body>
[0051] FIG. 7 is a perspective view for describing a first embodiment of a dual structure body having the heating/reflecting plate 70 of FIG. 5 and the cooling plate 80 of FIG. 6 assembled together. FIG. 7 illustrates a dual structure body 90 A having the heating/reflecting plate 70 and the cooling plate 80 supported and fixed to each other by supporting members 91 , 92 in a manner where the supporting members 91 , 92 are interposed between the heating/reflecting plate 70 and the cooling plate 80 . The supporting members 91 , 92 are formed of a heat insulating material such as ceramic. By positioning the heating/reflecting plate 70 and the cooling plate 80 in a manner facing each other and having a slight space (e.g., 1 mm) provided between the heating/reflecting plate 70 and the cooling plate 80 , an air layer, which acts as a thermal insulating material, can be formed between the heating/reflecting plate 70 and the cooling plate 80 .
[0052] In FIG. 7 , the dual structure body 90 A and dual structure bodies 90 B- 90 D formed in the same manner as the dual structure body 90 A are arranged in a manner surrounding the four sides of the electronic component (rework target) 21 provided on the upper surface of the printed circuit board 20 via the supporting members 91 , 92 and supporting members 93 , 94 formed in the same manner as the supporting members 91 , 92 .
[0053] Accordingly, thermal conductance from the printed circuit board 20 can be restrained (controlled) at an area between the electronic component 21 and the peripheral components 22 , 23 , 25 , 26 , to thermally separate the electronic component 21 and the peripheral components 22 , 23 , 25 , 26 provided on the printed circuit board 20 .
[0054] FIG. 8 is a perspective view for describing a second embodiment of a dual structure body having the heating/reflecting plate 70 of FIG. 5 and the cooling plate 80 of FIG. 6 assembled together. FIG. 8 illustrates a dual structure body 100 having the heating/reflecting plate 70 and the cooling plate 80 supported by and fixed to each other by supporting members 95 , 96 in a manner where the supporting members 95 , 96 are interposed between the heating/reflecting plate 70 and the cooling plate 80 . The supporting members 91 , 92 are formed of a heat insulating material such as ceramic. By positioning the heating/reflecting plate 70 and the cooling plate 80 in a manner facing each other and having a slight space (e.g., 1 mm) provided between the heating/reflecting plate 70 and the cooling plate 80 , an air layer, which acts as a thermal insulating material, can be formed between the heating/reflecting plate 70 and the cooling plate 80 .
[0055] Supporting leg members 101 , 102 are fixed to the cooling plate 80 at an end part of the cooling plate holding member 82 substantially opposite from the metal cooling plate 81 . The supporting leg members 101 , 102 together with an end part of the metal heating plate 71 and an end part of the metal cooling plate 81 abut against the printed circuit board 20 , to allow the dual structure body 100 to maintain a predetermined position.
[0056] By preparing various dual structure bodies 100 having different widths W between the heating/reflecting plate 70 and the cooling plate 80 , the dual structure body 100 can be selected in accordance with the length and width of the electronic component 21 (rework target).
[0057] As illustrated in FIG. 9 , in a case of performing rework soldering, the rated value of the minimum temperature for joining the bumps of the electronic component 21 is no less than 230° C., and the rated value of the heat resistance temperature of the bumps of, for example, the peripheral components 22 , 23 is no greater than 170° C.
[0058] In a case of performing no temperature control and heating the electronic component 21 and the peripheral components 22 , 23 simply with the infrared heaters 27 , 28 , the temperature of the bumps of the electronic component 21 becomes 234° C. and the temperature of the bumps of the peripheral component 22 becomes 235° C. Thus, the temperature of the bumps of the peripheral component 22 surpasses the rated value of 170° C. Further, in a case of using a related art method described with FIG. 1 , the temperature of the bumps of the electronic component 21 becomes 230° C. and the temperature of the bumps of the peripheral component 22 becomes 205° C. Thus, the temperature of the bumps of the peripheral component 22 surpasses the rated value of 170° C.
[0059] In a case of using the embodiment described with FIG. 3 , the temperature of the bumps of the electronic component 21 becomes 230° C. and the temperature of the bumps of the peripheral component 22 becomes 167° C. Thus, both the temperatures of the bumps of the electronic component 21 and the bumps of the peripheral component 22 satisfy the rated values.
[0060] According to the above-described embodiments, by using a dual structure body having a heating/reflecting plate and a cooling plate arranged facing each other with a slight space provided therebetween, the heating/reflecting plate and the cooling plate can be mounted in a narrow space(s) between an electronic component and a peripheral component of a printed circuit board. Further, a rework soldering apparatus can be manufactured at a low cost because the dual structure body has a simple configuration. Further, with the dual structure body, lead free soldering of a printed circuit board can be achieved and components can be mounted on a printed circuit board at high density.
[0061] All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
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A method is disclosed for performing rework soldering for removing an electronic component from a printed circuit board and re-soldering the electronic component to the printed circuit board. The method includes the steps of positioning a dual structure body including a heating member and a cooling member between a rework target and a non-rework target placed on the printed circuit board, the heating member and the cooling member being arranged facing each other with a slight space provided therebetween, the heating member being situated toward the rework target, the cooling member being situated toward the non-rework target; heating the heating member; and cooling the cooling member.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/745,425, filed Dec. 21, 2012, which is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates generally to intravascular ultrasound (IVUS) imaging inside the living body and, in particular, to an IVUS imaging catheter that relies on a mechanically-scanned ultrasound transducer, including embodiments where the transducer includes a single crystal composite material.
BACKGROUND
[0003] Intravascular ultrasound (IVUS) imaging is widely used in interventional cardiology as a diagnostic tool for a diseased vessel, such as an artery, within the human body to determine the need for treatment, to guide the intervention, and/or to assess its effectiveness. IVUS imaging uses ultrasound echoes to create an image of the vessel of interest. The ultrasound waves pass easily through most tissues and blood, but they are partially reflected from discontinuities arising from tissue structures (such as the various layers of the vessel wall), red blood cells, and other features of interest. The IVUS imaging system, which is connected to the IVUS catheter by way of a patient interface module (PIM), processes the received ultrasound echoes to produce a cross-sectional image of the vessel where the catheter is placed.
[0004] In a typical rotational IVUS catheter, a single ultrasound transducer element is located at the tip of a flexible driveshaft that spins inside a plastic sheath inserted into the vessel of interest. The transducer element is oriented such that the ultrasound beam propagates generally perpendicular to the axis of the catheter. A fluid-filled sheath protects the vessel tissue from the spinning transducer and driveshaft while permitting ultrasound signals to freely propagate from the transducer into the tissue and back. As the driveshaft rotates (typically at 30 revolutions per second), the transducer is periodically excited with a high voltage pulse to emit a short burst of ultrasound. The same transducer then listens for the returning echoes reflected from various tissue structures, and the IVUS imaging system assembles a two dimensional display of the vessel cross-section from a sequence of these pulse/acquisition cycles occurring during a single revolution of the transducer.
[0005] In the typical rotational IVUS catheter, the ultrasound transducer is a piezoelectric ceramic element with low electrical impedance capable of directly driving an electrical cable connecting the transducer to the imaging system hardware. In this case, a single pair of electrical leads (or coaxial cable) can be used to carry the transmit pulse from the system to the transducer and to carry the received echo signals from the transducer back to the imaging system by way of a patient interface module (“PIM”) where the echo signals can be assembled into an image. An important complication in this electrical interface is how to transport the electrical signal across a rotating mechanical junction. Since the catheter driveshaft and transducer are spinning (in order to scan a cross-section of the artery) and the imaging system hardware is stationary, there must be an electromechanical interface where the electrical signal traverses the rotating junction. In rotational IVUS imaging systems, this problem can be solved by a variety of different approaches, including the use of rotary transformers, slip rings, rotary capacitors, etc.
[0006] While existing IVUS catheters deliver useful diagnostic information, there is a need for enhanced image quality to provide more valuable insight into the vessel condition. For further improvement in image quality in rotational IVUS, it is desirable to use a transducer with broader bandwidth and to incorporate focusing into the transducer. A piezoelectric micro-machined ultrasound transducer (PMUT) fabricated using a polymer piezoelectric material offers greater than 100% bandwidth for optimum resolution in the radial direction, and a spherically-focused aperture for optimum azimuthal and elevation resolution. While this polymer PMUT technology offers many advantages, the electrical impedance of the PMUT is too high to efficiently drive the electrical cable connecting the transducer to the IVUS imaging system by way of the PIM. Furthermore, the transmit efficiency of polymer piezoelectric material is much lower compared to that of the traditional lead-zirconate-titanate (PZT) ceramic piezoelectric. Therefore, the signal-to-noise ratio of a PMUT will be compromised unless the deficiency in acoustic output can be compensated for by improved transmit electronics and/or other signal processing advances.
[0007] Current approaches to form a focused ultrasound beam include the use of an acoustic lens using conventional PZT transducers. For example, a rubber lens with an acoustic velocity of 1.0 mm/μsec has been used for elevation focus in phased array ultrasound systems. These approaches pose complex fabrication problems and the difficulty of removing imaging artifacts in the resulting signal.
[0008] Accordingly, there remains a need for improved devices, systems, and methods for implementing focused piezoelectric micro-machined ultrasonic transducers within an intravascular ultrasound system.
SUMMARY
[0009] According to some embodiments, an ultrasound transducer for use in intra-vascular ultrasound (IVUS) imaging systems is provided that includes a single crystal composite (SCC) layer; a front electrode on a side of the SCC layer; and a back electrode on the opposite side of the SCC layer. In some embodiments, the SCC layer includes pillars made of a single crystal piezo-electric material. The pillars are embedded in a polymer matrix in some instances. The SCC layer has a dish shape, defined by a concave surface and opposing convex surface, in some embodiments. The back electrode is split into two electrodes electrically decoupled from one another in some implementations.
[0010] A method of forming an ultrasound transducer for use in IVUS imaging systems in some embodiments includes etching a single crystal; forming a polymer layer on the etched single crystal to form a single crystal composite (SCC) having a first thickness; placing a first electrode on a first side of the SCC; forming the SCC to a second thickness; placing a second electrode on a second side of the SCC; and placing the SCC on a molded tip.
[0011] An IVUS imaging system according to some embodiments may include an ultrasound emitter and receiver rotationally disposed within an elongate member; an actuator coupled to the ultrasound emitter, the actuator moving the ultrasound emitter through at least a portion of an arc; and a control system controlling the emission of a sequence of pulses from the ultrasound emitter and receiving from the receiver ultrasound echo data associated with the pulses, the control system processing the ultrasound echo data to generate a cross-sectional image of the vessel. In some embodiments the ultrasound emitter and receiver comprises an ultrasound transducer including a single crystal composite (SCC) layer; a front electrode; and a back electrode. In some embodiments the SCC layer includes pillars made of a single crystal piezo-electric material. The pillars are embedded in a polymer matrix in some instances. The SCC layer has a dish shape, with opposing concave and convex surfaces, in some embodiments.
[0012] These and other embodiments of the present disclosure will be described in further detail below with reference to the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG.1 is a schematic view of an imaging system according to an embodiment of the present disclosure.
[0014] FIG. 2 is a diagrammatic, partial cutaway perspective view of an imaging device according to an embodiment of the present disclosure.
[0015] FIG. 3 shows a partial view of an ultrasound transducer according to an embodiment of the present disclosure.
[0016] FIG. 4 shows a partial cross-sectional side view of a distal portion of an imaging device according embodiment of the present disclosure.
[0017] FIG. 5A shows a partial cross-sectional axial view of the distal portion of the imaging device of FIG. 4 along section line A-A′.
[0018] FIG. 5B shows a a partial cross-sectional axial view of the distal portion of the imaging device of FIG. 4 along section line B-B′.
[0019] FIG. 6A shows a partial plan view of a single crystal composite according to an embodiment of the present disclosure.
[0020] FIG. 6B shows a partial plan view of a single crystal composite according to another embodiment of the present disclosure.
[0021] FIG. 6C shows a partial plan view of a single crystal composite according to yet another embodiment of the present disclosure.
[0022] FIG. 7A shows a partial side view of an ultrasound transducer according to an embodiment of the present disclosure.
[0023] FIG. 7B shows a partial plan view of a distal portion of an imaging device incorporating the ultrasound transducer of FIG. 7A according to an embodiment of the present disclosure.
[0024] FIG. 7C shows a partial plan view of the ultrasound transducer of FIG. 7A according to an embodiment of the present disclosure.
[0025] FIGS. 8A-F show a series of partial cross-sectional side views of fabrication stages for an ultrasound transducer according to some embodiments of the present disclosure.
[0026] FIG. 9 shows a flow chart for a method of forming an ultrasound transducer according to some embodiments of the present disclosure.
[0027] In the figures, elements having the same reference number have the same or similar functions and/or features.
DETAILED DESCRIPTION
[0028] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It is nevertheless understood that no limitation to the scope of the disclosure is intended. Any alterations and further modifications to the described devices, systems, and methods, and any further application of the principles of the present disclosure are fully contemplated and included within the present disclosure as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately.
[0029] Embodiments disclosed herein are for an apparatus and a method of fabrication of the apparatus, the apparatus including a focused transducer to be used in a rotational IVUS catheter. A transducer as disclosed herein provides a broad bandwidth of ultrasound signals having focused beam propagation. Such an ultrasound beam provides a high three-dimensional (3D) resolution for ultra-sound imaging, including depth, lateral and elevation dimensions. In some embodiments, an IVUS catheter of the present disclosure provides a wide bandwidth, focused ultrasound beam without increasing the number of electrical connections to a circuit rotating together with the transducer. An ultrasound transducer according to embodiments disclosed herein may include a single crystal composite material that provides a wide bandwidth, focused beam. The single crystal composite material is shaped into an element having a curvature designed to provide a focused beam (e.g., defining a concave emitting surface for the ultrasound transducer) in some instances.
[0030] FIG. 1 shows an IVUS imaging system 100 according to an embodiment of the present disclosure. In some embodiments of the present disclosure, the IVUS imaging system 100 is a rotational IVUS imaging system. In that regard, the main components of the rotational IVUS imaging system are a rotational IVUS catheter 102 , a patient interface module (PIM) 104 , an IVUS console or processing system 106 , and a monitor 108 to display the IVUS images generated by the IVUS console 106 . Catheter 102 includes an ultrasound transducer 150 in some embodiments. PIM 104 implements the appropriate interface specifications to support catheter 102 . According to some embodiments, PIM 104 generates a sequence of transmit pulse signals and control waveforms to regulate the operation of ultrasound transducer 150 . PIM 104 may also receive a response signal form transducer 150 through the same pair of lines.
[0031] Ultrasound transducer 150 transmits ultrasound signals towards the vessel tissue based on the trigger signals received from PIM 104 . Ultrasound transducer 150 also converts echo signals received from the vessel tissue into electrical signals that are communicated to PIM 104 . PIM 104 also supplies high- and low-voltage DC power supplies to the rotational IVUS catheter 102 . In some embodiments, PIM 104 delivers a DC voltage to transducer 150 across a rotational interface. Options for delivering DC power across a rotating interface include the use of slip-rings, rotary transformers, and/or the implementation of the active spinner technology.
[0032] FIG. 2 shows a diagrammatic, partial cutaway perspective view of catheter 102 , according to an embodiment of the present disclosure. FIG. 2 shows additional detail regarding rotational IVUS catheter 102 . Rotational catheter 102 includes an imaging core 110 and an outer catheter/sheath assembly 112 . Imaging core 110 includes a flexible drive shaft that is terminated at the proximal end by a rotational interface 114 providing electrical and mechanical coupling to PIM 104 (cf. FIG. 1 ). The distal end of the flexible drive shaft of the imaging core 110 is coupled to a transducer housing 116 containing ultrasound transducer 150 and associated circuitry.
[0033] Catheter/sheath assembly 112 includes a hub 118 supporting rotational interface 114 and provides a bearing surface and a fluid seal between rotating and non-rotating elements of catheter 102 . In some embodiments, hub 118 includes a luer lock flush port 120 through which saline is injected to flush out the air and fill the inner lumen of the sheath with an ultrasound-compatible fluid at the time of use of the catheter. Saline also provides a biocompatible lubricant for the rotating driveshaft. In some implementations, hub 118 is coupled to a telescope 122 that includes nested tubular elements and a sliding fluid seal that permits catheter/sheath assembly 112 to be lengthened or shortened. Telescope 122 facilitates axial movement of the transducer housing within an acoustically transparent window 124 at the distal portion of catheter 102 .
[0034] In some embodiments, window 124 is composed of thin-walled plastic tubing fabricated from material(s) that readily conduct ultrasound waves between the transducer and the vessel tissue with minimal attenuation, reflection, or refraction. A proximal shaft 126 of catheter/sheath assembly 112 bridges the segment between telescope 122 and window 124 . In some embodiments, proximal shaft 126 is composed of a material or composite that provides a lubricious internal lumen and optimum stiffness to catheter 102 . Embodiments of window 124 and proximal shaft 126 in catheter 102 may be as described in detail in U.S. Pat. Application entitled “Intravascular Ultrasound Catheter for Minimizing Image Distortion,” Attorney docket No. 44755.938, the contents of which are hereby incorporated in their entirety by reference, for all purposes.
[0035] FIG. 3 shows a partial view of ultrasound transducer 150 according to some embodiments disclosed herein. Transducer 150 includes a single crystal composite material (SCC) 301 having pillars 320 of a single crystal piezo-electric material embedded in a polymer matrix 330 . In some embodiments polymer matrix 330 is formed by epoxy. The epoxy used as filler in polymer matrix 330 provides flexibility to the SCC material forming ultrasound transducer 150 .
[0036] In some embodiments, an impedance matching layer 310 is included in ultrasound transducer 150 . Impedance matching layer 310 facilitates coupling of the acoustic wave with the medium surrounding ultrasound transducer 150 . Soft polymer matrix 330 reduces the acoustic impedance to SCC 301 , thus providing high efficiency and broad bandwidth to transducer 150 for acoustic coupling. In some embodiments, matching layer 310 may be a quarter-wave matching layer added to SCC 301 , to further improve efficiency and bandwidth of transducer 150 , thus enhancing sensitivity.
[0037] According to some embodiments disclosed herein, pillars 320 form structures elongated in an axial direction (Y-axis in FIG. 3 ) having a narrow diameter in cross section (Z-axis in FIG. 3 ). The cross section of pillars 320 is in a plane of SCC 301 forming ultrasound transducer 150 . Further according to some embodiments, polymer matrix 330 is continuous in the axial direction (Y-axis) and in the plane of SCC 301 forming ultrasound transducer 150 (XZ-plane). The anisotropic nature of SCC 301 confines the electric field E within pillars 320 , which have a high dielectric constant. Fringe fields at the edges of electrodes 151 and 152 are mitigated by polymer matrix 330 . Thus, in some embodiments the performance of transducer 150 is not degraded by fringe fields at electrode boundaries. According to some embodiments, the thickness (or height) of pillars 320 may be 50 μm or less, for 40 MHz center frequency operation. In some embodiments a thickness-to-width aspect ratio of at least 2 or greater may be desirable, resulting in pillars 320 having a diameter of 20 μm or less.
[0038] Accordingly, SCC 301 can be made using deep reactive ion etching (DRIE) applied to a single crystal material. Etch a matrix pattern using DRIA and fill the etched trenches with epoxy. Then grind away back side and polish front side and have a resulting composite layer. A horizontal resonant frequency (oscillations in the XZ plane in FIG. 3 ) is so far apart from vertical frequency (oscillations along the Y-axis in FIG. 3 ) there is little energy expended by horizontal resonance. This makes the transducer more efficient. Wide bandwidth is achieved by efficiently coupling into medium (for example, using a matching layer). A matching layer overcomes acoustic impedance mismatch between transducer material and the transmitting medium. A PZT has impedance of about 30 while that of blood/saline solutions is about 1.6/1.5. A matching layer allows the transition from the PZT material to the transmitting medium more efficient. In some embodiments, the epoxy used to form SCC 301 may be used as an impedance matching layer. The impedance of epoxy is about 3, while impedance of SCC 301 depends on distribution of PZT ceramic pillars within the epoxy matrix. In some embodiments the acoustic impedance of SCC 301 may be approximately 10. Adding a matching layer and/or a backing material to transducer 150 increases the bandwidth. The shape of pillars 320 may lightly impact the device bandwidth and center frequency of operation. Acoustic loss of the epoxy matrix affects the bandwidth of transducer 150 . The epoxy serves to absorb or dissipate sound. Any energy that attempts to stay in the plastic will be absorbed quickly. An added advantage of SCC 301 is the higher electric field density in pillars 320 relative to epoxy matrix 330 due to the higher dielectric constant of the PZT ceramic relative to the epoxy. This increases the coupling efficiency of the transducer.
[0039] A piezoelectric material typically has a 20:1 acoustic impedance mismatch with blood and saline. A composite material increases the proportion of epoxy and polymers in transducer 150 , reducing acoustic impedance and providing better impedance matching. Bandwidth may be improved by including a backing material overlaid on transducer 150 to absorb acoustic energy, increasing bandwidth at the cost of somewhat reduced signal strength.
[0040] SCC 301 provides high efficiency and broad bandwidth for ultrasound generation and sensing, which is desirable in medical applications. According to some embodiments, single crystal piezoelectric materials used in SCC 301 have a high electromechanical coupling coefficient. The electromechanical coupling coefficient of single crystal piezoelectric materials is typically higher than PZT ceramic. Thus, the voltage levels needed for a predetermined volume change is lower for the single crystal materials used in SCC 301 , relative to that of piezo-electric ceramics. This increases the power conversion efficiency of SCC 301 from radiofrequency energy into sound, and from sound into radiofrequency energy. Some embodiments include narrow pillars 320 that remove the lateral constraint on the piezoelectric material that is present in a continuous slab of material. The lateral constraint of a bulk crystal is related to the rigidity of the material, as the pillars embedded in epoxy stretch longitudinally, there is less resistance from the surrounding epoxy material since the epoxy material is less rigid. In such embodiments, low frequency lateral modes (in the XZ-plane in FIG. 3 ) in the vicinity of the desired ultrasound frequency are suppressed in narrow pillars 320 by the surrounding polymer matrix 330 . Thus, most of the RF electrical energy in SCC 301 is transferred to ‘height’ vibration modes (Y-axis in FIG. 3 ) in pillars 320 , which couple to the ultrasound waves forming the probe beam. In some embodiments, polymer matrix 330 reduces the acoustic impedance of SCC 301 compared to that of a single crystal material. Indeed, the young modulus of polymer matrix 330 is lower than that of the single crystal 320 , or that of a piezo-electric ceramic. For example, in some embodiments SCC 301 may include 75% in volume of polymer matrix 330 . Such a composite has low acoustic impedance compared to a slab of single crystal piezoelectric or piezo-ceramic material. This low acoustic impedance is better matched to tissue acoustic impedance, therefore providing high efficiency and broad bandwidth to SCC 301 .
[0041] The dimensions of SCC 301 vary according to the specific application sought. For example, the target ultrasound frequency and bandwidth determine the specific dimensions of SCC 301 in some instances. In some embodiments pillars 320 are about 10 μm in diameter (Z-axis in FIG. 3 ) with 10 μm deep kerfs (pillar height, Y-axis in FIG. 3 ). For high frequency IVUS, it may be desirable to have even smaller structures and kerfs in SCC 301 . In some embodiments single crystal materials may be desirable in SCC 301 for high frequency applications because single crystals may be patterned using deep reactive ion etching (DRIE). DRIE techniques may be used to pattern the crystalline substrate with micron accuracy to fabricate SCC 301 materials on a wafer scale.
[0042] The volume fraction of polymer matrix 330 in SCC 301 may also vary according to the specific application. For example, the volume fraction of polymer matrix 330 determines the impedance of the transducer material which is beneficial to match acoustical impedance of the tissue of interest for the use of the ultrasound beam in some instances. The thickness of the composite crystal is determined by the resonance frequency desired. The thickness of SCC 301 is chosen to obtain a pre-selected center frequency of a transmitted ultrasound signal from transducer 150 .
[0043] FIG. 4 shows a partial perspective view of transducer housing 116 , including ultrasound transducer 150 according to some embodiments. Ultrasound transducer 150 includes SCC 301 and impedance matching layer 310 . Other details of ultrasound transducer 150 are omitted in FIG. 4 , for clarity. It is understood that ultrasound transducer 150 in FIG. 4 may include the same or similar elements as shown in FIG. 3 . For example, ultrasound transducer 150 in FIG. 4 may include back electrode 151 , and front electrode 152 .
[0044] In some embodiments SCC 301 is deformed into a curved shape. For example, SCC 301 is deformed into a dish-shaped structure having a symmetry axis included in a plane that also includes the Z-axis in FIG. 3 . In some embodiments, the dish-shaped structure may be symmetric about the BD axis, which may be parallel to the Y-axis, or may be forming an angle relative to the Y-axis. This may be desirable for providing a focused ultrasound beam. For example, in some instances SCC 301 is deformed such that the upper surface of SCC 301 as viewed in FIG. 3 becomes concave. In some implementations, the concave shape of the upper surface of SCC 301 is generally spherical. Further, in some instances the deformation of SCC 301 results in the lower surface of SCC 301 being convex. In some implementations, the convex shape of the lower surface of SCC 301 is generally spherical. In some particular implementations, the concave upper surface and the convex lower surface are both generally spherical with a common center point.
[0045] Transducer housing 116 is in a distal portion of catheter 102 according to an embodiment of the present disclosure. In particular, FIG. 4 shows an expanded view of aspects of the distal portion of imaging core 110 . In this exemplary embodiment, imaging core 110 is terminated at its distal tip by housing 116 . Housing 116 may be fabricated from stainless steel or other suitable biocompatible material, and have a bullet-shaped or rounded nose, and an aperture 128 for an ultrasound beam. Thus, ultrasound beam 130 may emerge from housing 116 , through aperture 128 . In some embodiments, flexible driveshaft 132 of imaging core 110 is composed of two or more layers of counter wound stainless steel wires. Flexible driveshaft 132 is welded or otherwise secured to housing 116 such that rotation of flexible driveshaft 132 also imparts rotation to housing 116 . In the illustrated embodiment, an electrical cable 134 delivers the high-voltage transmit pulse and carries the low amplitude echo signal back to PIM 104 . with an optional shield 136 provides electrical power to SCC 301 . Electrical cable 134 extends through an inner lumen of flexible driveshaft 132 to the proximal end of imaging core 110 where it is terminated to the electrical connector portion of the rotational interface 114 (cf. FIG. 2 ). SCC 301 is mounted onto molded tip 148 . Molded tip 148 may be formed of a polymer material such as epoxy, and serve as an acoustic backing material to absorb acoustic reverberations propagating within housing 116 . Molded tip 148 provides strain relief for electrical cable 134 at the point of soldering to electrodes 151 and 152 in some instances. In some embodiments, a flexible sheet of material is molded into bowl shaped substrate to have a concave shape.
[0046] According to some embodiments, molded tip 148 is formed such that an upper surface of the molded tip is concave so that when ultrasound transducer 150 is placed on the concave upper surface, the flexibility of SCC 301 allows ultrasound transducer 150 to acquire a corresponding curved shape. In some instances, a bottom surface of the ultrasound transducer 150 matches the curvature of the upper surface of the molded tip 148 . Accordingly, in some such instances the bottom surface of the ultrasound transducer 150 becomes convex and an opposing upper surface of the ultrasound transducer becomes concave (as shown in FIGS. 4 and 5B ). The convex shape of the lower surface of the ultrasound transducer 150 may have an apex along the axis of beam direction BD such that a tangent to apex of the surface forms an angle θ with a longitudinal axis of catheter 102 (Z-direction in FIG. 4 ). In that regard, in some embodiments the concave upper surface of the ultrasound transducer 150 is symmetrical about the axis of beam direction BD such that ultrasound beam 130 emitted from the ultrasound transducer 150 propagates along direction BD into the vessel tissue. FIG. 4 shows a BD substantially orthogonal to the longitudinal axis of catheter 102 (0˜90°). One of ordinary skill will recognize that angle θ may have values smaller than 90° or larger than 90°, depending on the desired features for ultrasound data processing. In that regard, in some implementations, the ultrasound transducer 150 is mounted such that the ultrasound beam 130 propagates at an oblique angle with respect to the longitudinal axis of the catheter.
[0047] The curvature adopted by ultrasound transducer 150 according to embodiments as disclosed herein provides focusing for beam 130 . In some embodiments aperture 128 may be about 500 μm in diameter (d), and a focal length, f:3d, may be desired to obtain sufficient resolution and depth of field. Thus, the geometric focus of ultrasound beam 130 may be about 1 mm outside the sheath (1.5 mm from the aperture). For a curved transducer of this geometry, the depth of the dish should be approximately 20 μm. In some embodiments, the wavelength of a center frequency of an ultrasound signal transmitted by transducer 150 is about 40 μm in the transducer material. Accordingly, the diameter of the transducer may fit about a ten, a dozen, or a similar number of wavelengths within its surface.
[0048] In some embodiments an acoustic lens may be used to provide focusing to beam 130 . To achieve a lens, some embodiments may use silicone or some other polymer that reduces sound speed through the lens material relative to that of the medium. For example, ultrasound waves may travel at a 1.0 mm/μsec velocity in a silicone lens, versus 1.5 mm/μsec medium velocity. This may provide a similar focusing power (f:3d) to the 20 μm deep dish described above with a lens thickness of approximately 60 μm. Such a lens may be formed by surface tension under a microscope, to control thickness. For example a lens may be formed with a glue drop having a concavity provided by surface tension. A material may be as silicon rubber (slow material). But careful with losses.
[0049] The curved transducer approach as shown in FIG. 4 facilitates mitigating reflections, reverberation, attenuation, and other diffraction effects resulting from using refractive elements in the path of ultrasound beam 130 in some embodiments.
[0050] FIG. 5A shows a partial cross-section view of a transducer housing including electrical leads 134 - 1 and 134 - 2 , according to some embodiments. FIG. 5A results from taking a cut away view of FIG. 4 along line AA′. Electrical leads 134 - 1 and 134 - 2 may be collectively referred to as leads 134 (cf. FIG. 4 ). Leads 134 may be coupled to bonding pad 506 (lead 134 - 1 ) and to bonding pad 507 (lead 134 - 2 ). Bonding pads 506 and 507 may have electrical contact with either of electrodes 151 and 152 in ultrasound transducer 150 . In some instances, electric leads 134 - 1 and 134 - 2 provide a high and a low voltage signal coupled to SCC 301 through electrodes 151 and 152 . In some embodiments lead 134 - 1 is coupled to back electrode 151 and lead 134 - 2 is coupled to front electrode 152 . Further, according to some embodiments leads 134 - 1 and 134 - 2 are coupled to different portions of back electrode 151 . In such configurations, front electrode 152 may have a floating voltage having a value between the voltages provided by leads 134 - 1 and 134 - 2 . Embodiments having a floating electrode 152 may reduce the connections used inside housing 116 . In particular, embodiments having a floating electrode 152 may enable the use of a continuous index matching layer 310 .
[0051] FIG. 5B shows a partial cross-section view of transducer housing 116 , including ultrasound transducer 150 , according to some embodiments. FIG. 5B results from taking a cut away view of FIG. 4 along line BB′. FIG. 5B illustrates aperture 128 formed above ultrasound transducer 150 to allow ultrasound beam 130 to pass through, into and from the vessel tissue. FIG. 5B also shows window 124 , which is transparent to the ultrasound beam 130 coupling transducer 150 with the vessel tissue (cf. FIG. 2 ).
[0052] FIGS. 6A , 6 B, and 6 C show partial plan views of single crystal composites 601 A, 601 B, and 601 C, respectively, according to embodiments disclosed herein. Without loss of generality, SCC 601 A, SCC 601 B, and SCC 601 C in FIGS. 6A , 6 B, and 6 C are shown in a plane XZ consistent with Cartesian coordinate axes shown in FIGS. 1-5B . One of ordinary skill in the art will recognize that an ultrasound transducer fabricated from any one of SCC 601 A, 601 B, and 601 C may have any orientation in 3D space. In particular, as has been discussed above, an ultrasound transducer formed from SCC 601 A, SCC 601 B, and SCC 601 C may have a 3D curvature forming a dish shape having a symmetry axis, BD, as shown in FIG. 4 . SCC 601 A, SCC 601 B, and SCC 601 C (collectively referred to as SCC 601 ) include pillars 620 A, 620 B, and 620 C, respectively (collectively referred to as pillars 620 ). Pillars 620 in SCC 601 are embedded in polymer matrix 630 . In some embodiments polymer matrix 630 may be as polymer matrix 330 , described in detail with reference to FIG. 3 , above. Also illustrated in FIGS. 6A , 6 B, and 6 C is a cutout path 650 in the XZ plane. Cutout path 650 may be formed with a laser beam on portions of SCC 601 including polymer matrix 630 .
[0053] One of ordinary skill will recognize that the portion of the total area of SCC 601 A, 601 B, and 601 C covered by pillars 620 A, 620 B, and 620 C may vary. In some embodiments pillars 620 A, 620 B, and 620 C may cover an area of about 25% of a surface area of SCC layer 601 A, 601 B, and 601 C, respectively.
[0054] As shown in FIG. 6A , SCC 601 A includes pillars 620 A having a circular cross-section in the XZ plane. As shown in FIG. 6B , SCC 601 B includes pillars 620 B having a square cross-section in the XZ plane. As shown in FIG. 6C , SCC 601 C includes pillars 620 C having puzzle-piece cross-section in the XZ plane. One of ordinary skill would recognize that the particular shape of pillars in SCC 601 in the XZ plane is not limiting. Some embodiments may include pillars having cross-sections in the XZ plane with dog-bone shape, pseudo-random shape, and hexagonal shape.
[0055] Embodiments such as SCC 601 A, 601 B, 601 C, or similar non-traditional shapes provide improved fill efficiency in the XZ plane, improved adhesion to polymer matrix 630 , greater flexibility, and better suppression of undesired lateral modes (in the XZ plane). Furthermore, SCC 601 provides improved mechanical integrity during the wafer thinning process. Patterning the finished transducer with cutout path 650 is also a valuable benefit. In some embodiments, cutout path 650 may form a circular or elliptical transducer shape. Ultrasound transducers having circular or elliptical shapes offer good performance in terms of side-lobe levels, compared to cutout paths having rectangular or square shapes.
[0056] The geometrical configuration of pillars 620 shown in FIG. 6 is not limiting to patterns 620 A, 620 B, or 620 C. One of ordinary skill will recognize that many configurations are possible. In some embodiments the aperture formed by SCC 601 may be apodized by adjusting the density of pillars 620 near the edges of the aperture (close to cutout path 650 ) to further reduce side-lobe levels. Some embodiments include pillars 620 having cross-sections with shapes obtained from Escher style tessellations of XZ-plane. In some embodiments, odd-shaped but uniform pillars 620 are used.
[0057] FIG. 7A shows a partial side view of an ultrasound transducer 750 according to some embodiments disclosed herein. Embodiments of split back electrode transducer 750 include a back electrode divided into two equal halves 751 - 1 and 751 - 2 . In some embodiments, halves 751 - 1 and 751 - 2 have a D-shape where the transducer has a circular or elliptical profile. Halves 751 - 1 and 751 - 2 are electrically decoupled from one another, so that each half may be coupled to a different voltage. The front electrode is continuous over the entire front surface of transducer 750 in some instances. In ultrasound transducer 750 the electrode connections to electrical cables 734 - 1 and 734 - 2 are provided from the back side. Thus, the back electrode in ultrasound transducer 750 includes back side portion 751 - 1 connected to cable 734 - 1 , and back side portion 751 - 2 connected to cable 734 - 2 . According to some embodiments, front electrode 752 may float with no direct contact to an outside voltage source, or ground. Ultrasound transducer 750 includes SCC 701 , which may include single crystal pillars embedded in a polymer similar to SCC 301 and SCC 601 as described in detail above (cf. FIGS. 1 , 6 A, 6 B, and 6 C).
[0058] Some embodiments of ultrasound transducer 750 with a split back electrode configuration as in FIG. 7A include SCC 701 having two halves 701 - 1 and 701 - 2 , poled in opposite directions. For example, a first half SCC 701 - 1 coupled to electrode 751 - 1 may be poled in a first direction, and a second half SCC 701 - 2 coupled to electrode 751 - 2 may be poled in a second direction opposite to the first direction. SCC may support a split polarization without significant artifacts due to the separation between individual pillars provided by the polymer matrix. According to some embodiments, cable 734 - 1 may couple electrode 751 - 1 to a voltage supply at a first voltage. Also, cable 734 - 2 may couple electrode 751 - 2 to a voltage supply at a second voltage, higher than the first voltage. When the two back electrodes are excited with equal and opposite signals, the front electrode remains at virtual ground by symmetry, and each of transducer halves 701 - 1 and 701 - 2 receive equal and opposite electrical excitation. Electric field 761 is opposite in direction to electric field 762 . Likewise, the polarization induced in SCC 701 - 1 by electric field 761 is opposite to the polarization induced in SCC 701 - 2 by electric field 762 . Since SCC 701 - 1 and SCC 701 - 2 are poled in opposite directions, the piezo-electric effect on first half 701 - 1 is the same as the piezo-electric effect on second half 701 - 2 . Thus, an acoustic wave-front including the two halves of split electrode transducer 750 is generated. Accordingly, in some embodiments halves 701 - 1 and 701 - 2 vibrate in phase with one another, providing a full aperture beam.
[0059] A single crystal composite as disclosed herein is particularly well suited to the split back electrode configuration. Fringe fields at the boundary between the split electrodes 751 - 1 and 751 - 2 are mitigated by polymer matrix 330 . This ensures that poling of halves 701 - 1 and 701 - 2 provides a well-defined orientation near their border.
[0060] Some embodiments using ultrasound transducer 750 including a split electrode may yield a lower capacitance (higher impedance) device. Indeed, each of the two capacitors formed between electrode 751 - 1 , 752 , and 751 - 2 has a lower capacitance than a capacitor made of the same SCC 701 material and having the same thickness, but double the area. Furthermore, in the split electrode configuration the two capacitors formed between electrodes 751 - 1 , 752 , and 751 - 2 are connected in series, thus reducing the net capacitance of SCC 701 as compared to a configuration where back electrodes 751 - 1 and 751 - 2 form a single electrode. Thus, embodiments of SCC 701 having a split back electrode may use a higher excitation voltage to achieve the same ultrasound output as a conventional electrode. Embodiments consistent with the split electrode configuration illustrated in FIG. 7A provide desirable manufacture features, since front electrode 752 is floating and may not use a direct connection to a voltage source, or ground. This simplifies the configuration and manufacturing of ultrasound transducer 750 and tip housing 116 . For example, an impedance matching layer such as layer 310 (cf. FIG. 3 ) may be formed as a continuous layer on top of front electrode 752 .
[0061] Split back electrode transducer 750 is desirable in embodiments including matching layer 310 . The use of a split back electrode permits matching layer 310 to be formed at the wafer level fabrication of transducer 750 without having a conductive material making contact with front electrode 752 . Thus, fabrication methods according to some embodiments may avoid cutting a hole in matching layer 310 for a front electrode contact.
[0062] FIG. 7B shows a partial plan view of ultrasound transducer 750 according to some embodiments disclosed herein. FIG. 7B illustrates back electrodes 751 - 1 and 751 - 2 . FIG. 7B also illustrates molded tip 148 (cf. FIG. 4 ). In some embodiments electrodes 751 - 1 and 751 - 2 in the distal area close to the tip of molded tip 748 may include a gold plated diamond grit. Bond pads 761 - 1 and 761 - 2 provide electrical contact to electrodes 751 - 1 and 751 - 2 from electrical cables such as cables 134 - 1 and 134 - 2 (cf. FIG. 5A ). Such configuration ensures efficient and reliable electrical contact to SCC 701 . Bond pads 761 - 1 and 761 - 2 may be formed of any conductive material, like gold or silver. One of ordinary skill would recognize that the specific material forming bond pads 761 - 1 and 761 - 2 is not limiting and any conductive material or alloy thereof may be used, without limitation.
[0063] In embodiments using a gold plated diamond grit, SCC 701 is pressed and glued onto molded tip 148 . Thus, protuberances in the diamond grit poke into the electrode plating on the back of the sheet formed by SCC 701 , providing a low resistance electrical connection. Some embodiments may include anisotropic conductive adhesives to provide a reliable electrical connection to SCC 701 . For example, an insulating epoxy-like material filled with gold or silver spheres provides an anisotropic conductive adhesive in some implementations. In such embodiments the density of the conductive spheres is low enough that the material is non-conductive, but when the material is compressed into a thin film between two conductive surfaces, the spheres are squished between the conductors and they bridge the narrow gap to again form a low resistance connection along the compression direction.
[0064] FIG. 7C illustrates front electrode 752 , which may be the common electrode for SCC transducer 750 . In some embodiments electrode 752 includes alignment tab 770 to orient the device properly within molded tip 148 . The SCC may include an epoxy matching layer. An acoustic impedance approximately equal to 3 is desirable.
[0065] According to some embodiments, SCC 701 including electrodes 752 , 751 - 1 , and 751 - 2 is glued into molded tip 148 forming a dish-shape for providing focused beam 130 (cf. FIG. 4 ).
[0066] FIGS. 8A-F show a partial view of fabrication stages for an SCC 801 , according to some embodiments. FIG. 8A illustrates single crystal material 802 formed into a slab of material 801 A, patterned using photolithography and DRIE (or other suitable etching and/or material removal processes) to etch away portions 825 of material. SCC material 802 may be any single crystal, piezo-electric material. For example, some embodiments may use a single crystal including lead magnesium niobate-lead titanate (PMN-PT). Slab 801 A may be formed on a wafer, having a front surface (top of FIG. 8A ) and a back surface (bottom of FIG. 8B ). This leads to a slab of material 801 B having isolated pillars or ribs 820 , partially formed through the wafer, as illustrated in FIG. 8B . In some embodiments a pattern of trenches is etched in the piezo-electric substrate using DRIE to produce vertical walls (Y-direction) and a very precise geometry (XZ plane), typically with 1 tm resolution. After etching, the trenches are filled with a polymer 830 such as epoxy or silicone, as illustrated in FIG. 8B .
[0067] FIG. 8C illustrates the forming of slab 801 C, according to some embodiments. Polymer layer 830 may be on the front side of the ultrasound transducer in slab 801 B, and material 802 may be on the back side of slab 801 B. In some embodiments polymer layer 830 may be polished, ground, or etched to a thickness such that polymer layer 830 and pillars 830 have an edge on the front side of SCC 801 .
[0068] Thus, slab 801 C includes pillars 820 of a piezo material, isolated from one another on the front side (top of FIG. 8C ), contained within polymer matrix 830 . The flexibility of slab 801 C is adjustable based on the size of the trenches formed in the DRIE step and the properties of the polymer used in matrix 830 . Further, slabs 801 C may have different geometries obtained by photolithography and DRIE steps, as described above. In some embodiments, the pattern of pillars 820 may be isolated islands separated by large moats.
[0069] FIG. 8D illustrates forming of slab 801 D, including a front electrode 852 . Forming slab 801 D may include forming the SCC layer into a desired thickness. To accomplish this, material 802 in the back side of slab 801 C (bottom of FIG. 8C ) may be polished, ground, or etched to a thickness such that polymer matrix 830 and pillars 820 have an edge on the back side of SCC 801 D. When the substrate is thinned to form a composite sheet having pillars 820 embedded in polymer matrix 830 , individual transducer elements forming an aperture can be selected by tracing a desired outline and removing polymer matrix 830 . In some embodiments, tracing the desired outline of individual elements and removing the polymer may be performed using a laser. The individual transducer elements are then electroplated to form a front electrode 852 in slab 801 D in some instances. Front electrode 852 is formed by electroplating a conductive material on the top portion of slab 801 D in some implementations. In some embodiments front electrode 852 and matching layer 810 are formed while the structure is part of the single wafer. The thickness of the structure may be 50 μm, 40 μm, 30 μm, or less. In some embodiments, the epoxy layer may be ground to form an impedance matching layer having a ¼ wavelength thickness (or approximately 15 μm in epoxy).
[0070] FIG. 8E illustrates the forming of a back electrode 851 in slab 801 E. Back electrode 851 and front electrode 852 may be as electrodes 151 and 152 described in detail above (cf. FIG. 3 ). Back electrode 851 may be formed in the same way as front electrode 852 (cf. FIG. 8D ). One of the advantages of SCC slab 801 E is that it has relatively low acoustic impedance, so it can provide a broad frequency response even without an acoustic matching layer.
[0071] FIG. 8F illustrates slab SCC 801 formed by depositing an acoustic impedance matching layer 810 on top of slab 801 E. Acoustic matching layer 810 is included in some embodiments of SCC 801 to match the acoustic impedance of the vessel tissue. Thus, acoustic matching layer 810 may further broaden the frequency response of an ultrasound transducer using SCC 801 .
[0072] Once a slab of SCC 801 is complete as shown in FIG. 8E or FIG. 8F , it may be installed in a catheter tip as an ultrasound transducer. According to some embodiments, SCC 801 is pressed into molded tip 148 (cf. FIG. 4 ). Molded tip 148 may include a curved shape to impart a curved shape to SCC 801 and produce a focused acoustic beam 130 . Molded tip 148 may also provide backing impedance to SCC 801 and attachment of the transducer to driveshaft 132 (cf. FIG. 4 ).
[0073] According to embodiments of the fabrication method illustrated in FIGS. 8A-F , the dimensions of an ultrasound transducer may be defined at the wafer level. Thus, the dimensions of a finished ultrasound transducer may be determined during the formation of slab 801 A (e.g., photolithography step) and slab 801 B (e.g., DRIE step). Furthermore, the finished ultrasound transducer may be segmented into smaller transducers of any desired size and shape. The flexibility of DRIE allows the formation of pillars 820 of arbitrary shape, forming arbitrary patterns within polymer matrix 830 . For example, some pillar cross-sections discussed herein are more desirable than traditional square pillars. Having pillars 820 embedded in polymer matrix 830 allows the formation of a round transducer that is cut out using laser ablation.
[0074] By having flexibility in the layout and pattern design of an ultrasound transducer, fabrication methods for SCC layers as disclosed herein provide a focused ultrasound beam using a simple electrical coupling to the transducer. Some embodiments further include a custom electronic chip, such as a micro-electromechanical system (MEMS), to provide more sophisticated acoustic beam manipulation or modulation.
[0075] FIG. 9 shows a flow chart for a method 900 of forming an ultrasound transducer according to embodiments disclosed herein. Method 900 will be described below in relation to the steps and structures illustrated in FIGS. 8A-F . Reference to the steps and structures in FIG. 8A-F is used for illustrative purposes only and is not limiting of the embodiments of method 900 consistent with the general concept expressed in FIG. 9 . One of ordinary skill would recognize that obvious variations to method 900 may be provided, while maintaining the overall concept as described below.
[0076] Step 910 includes etching a single crystal according to a pattern formed by lithography, such as in slab 801 A (cf. FIG. 8A ). In some embodiments, step 910 includes a DRIE procedure. Step 920 includes placing a polymer layer on the etched single crystal, to form a slab such as slab 801 B (cf. FIG. 8B ). In some embodiments step 920 includes filling a pillar pattern resulting from the etching step 910 with polymer, which may be an epoxy. Step 930 includes forming the polymer layer to a thickness, such as in slab 801 C (cf. FIG. 8C ). Step 930 may include lapping the surface of the wafer to removing excess epoxy, creating a planar surface and exposing the pillars. In step 940 an electrode is placed on the front side of the SCC.
[0077] Step 950 includes forming an SCC layer to a thickness, as in slab 801 D (cf. FIG. 8D ). In some embodiments step 950 includes grinding the back portion of the wafer including slab 801 D to release the composite structure from the wafer. Step 960 includes placing a back electrode to form a slab such as slab 801 E (cf. FIG. 8E ). According to some embodiments, step 960 may include similar procedures as step 940 to place front electrode 852 on slab 801 D. In some embodiments, slab 801 E is formed with a plurality of individual transducer elements, each forming an aperture. Step 960 may include cutting individual transducers from slab 801 E. The cutting process could be made using a laser to cleanly remove epoxy filler 830 surrounding isolated groups of pillars 820 . Thus, the piezoelectric material in pillars 820 may be left intact in step 960 .
[0078] Step 970 includes placing an impedance matching layer on one electrode. Step 970 may include grinding the matching layer to a desired thickness.
[0079] Step 980 includes placing the SCC material thus formed on a molded tip, such as molded tip 148 . Once the individual transducer is available, it can be pressed into a micro-molded housing that will become the tip of the flexible driveshaft in a rotational IVUS catheter. The molded housing may include a dish-shaped depression to form the desired aperture deflection. In some embodiments, step 980 is performed once the front and back electrodes are in place (steps 940 and 960 ). Step 980 may also include forming bonding pads to bridge the gap between the electrical leads inside the driveshaft (e.g., a shielded twisted pair) and the split back electrodes of the transducer. Such bonding pads may be as described in detail above in reference to bond pads 761 - 1 and 761 - 2 (cf. FIG. 7B ). In some embodiments the fabrication process may include a “Cast-In-Can” method to form a transducer on a molded tip. In some embodiments, the transducer is pressed into the micro-molded tip subassembly. In some embodiments the transducer is placed on a molded tip such that acoustic beam 130 is formed in a plane perpendicular to the longitudinal axis of the catheter (XY plane in FIG. 2 ). According to some embodiments, the transducer is placed on a molded tip such that acoustic beam 130 extends at an oblique angle with respect to the longitudinal axis (Z-axis) of the catheter.
[0080] Embodiments of the present disclosure described above are exemplary only. One skilled in the art may recognize various alternative embodiments from those specifically disclosed. Those alternative embodiments are also intended to be within the scope of this disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure.
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An ultrasound transducer for use in intra-vascular ultrasound (IVUS) imaging systems including a single crystal composite (SCC) layer is provided. The transducer has a front electrode on a side of the SCC layer; and a back electrode on the opposite side of the SCC layer. The SCC layer may have a dish shape including pillars made of a single crystal piezo-electric material embedded in a polymer matrix. Also provided is an ultrasound transducer as above, with the back electrode split into two electrodes electrically decoupled from one another. A method of forming an ultrasound transducer as above is also provided. An IVUS imaging system is provided, including an ultrasound transducer rotationally disposed within an elongate member; an actuator; and a control system controlling activation of the ultrasound transducer to facilitate imaging.
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BACKGROUND OF THE INVENTION
[0001] 1. Technical Field.
[0002] The invention relates to a device for administering an injectable product.
[0003] 2. Description of the Related Art.
[0004] Injection devices, for example injection syringes or injection pens, such as the invention relates to in particular though not exclusively, conventionally comprise a casing which accommodates an ampoule with the product to be injected, a delivering means for delivering the product out of the ampoule and a coupling means. The delivering means is conventionally formed by a piston which is movable in the ampoule. In simple syringes, the muscular power of the user serves as the drive means. The use of spring elements, in particular pressure springs, as the drive means is also known. The coupling means forms a transmission link or drive connection from the drive means to the delivering means.
[0005] The known drive means, for example drive springs, have the disadvantage that the drive force or drive energy applied by them is subject to changes in the course of being released. In drive springs, the drive energy changes in accordance with the spring characteristic. The delivering rate of the delivering means follows such changes. Correspondingly, the delivery rate changes in the course of delivery in accordance with the changing drive energy.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to provide a device for administering an injectable product, with which the product is evenly delivered in the course of an injection or infusion.
[0007] The invention is based on a device for administering an injectable product which includes a casing, a container for the product accommodated by the casing, a delivering means, a drive means and a transmission link or coupling means. The product is delivered directly out of the container by the delivering means. The drive means supplies the drive energy required for this, said drive energy being transmitted in the transmission link to the delivering means, in such a way that the delivering means is driven by the drive means, to deliver the product.
[0008] The container, the delivering means, the drive means and the transmission members of the transmission link are preferably arranged in the casing. Other arrangements are, however, in principle equally possible. The injectable product is preferably a medical or cosmetic agent, in particular in the form of a liquid active solution. A prominent example is insulin, administered using the device within the context of a treatment for diabetes. The device is preferably an infusion device. It can, however, also be an injection device. The container can, in particular, be formed as an ampoule, as is the case in known infusion devices. The delivering means is preferably formed by a piston accommodated by the container, which is advanced towards an outlet of the container, to deliver the product. However, instead of such a piston, the delivering means can in principle be formed by any type of pump suitable for delivering the product.
[0009] According to its type, the drive means is preferably formed in such a way that it releases the energy stored in it when it is triggered. Via a coupling means, this released energy is transmitted in the transmission link to the delivering means which, driven for its part in this way, delivers the product out of the container. The drive means is preferably formed by a drive spring, particularly preferably a pressure spring. In principle, however, other designs of drive means may also be used, e.g. those which release a pressure gas when triggered.
[0010] According to the invention, a fluid space for an incompressible fluid and a pressure reducing means are provided in the transmission link from the drive means to the delivering means, i.e. in the coupling means.
[0011] The fluid space correspondingly comprises a drive side, upon which the drive means acts, and a driven side, which acts on the delivering means. Both the drive side and the driven side can be connected, directly or via other transmission members, to the drive means and/or delivering means respectively. The fluid space can be impinged on its drive side by pressure from the drive means. The pressure thus generated is reduced toward the driven side of the fluid space by the pressure reducing means. The pressure is preferably reduced to a fifth or less and particularly preferably to a tenth or less by means of the pressure reducing means. The pressure reducing means creates a fluid connection which only allows a delayed flow of the fluid from the drive side towards the driven side, such that in a dynamic state, i.e. while the delivering means is being driven, a greater fluid pressure prevails on the drive side than on the driven side.
[0012] The invention enables a drive means to be used in which substantially more energy is stored than would be required to drive the delivering means and the resulting delivery of the product. The comparatively large drive energy released when the drive means is triggered is attenuated by the fluid coupling in accordance with the invention onto the measure required for delivering and administering. The excess of drive energy is available, controlled due to the fluid coupling in accordance with the invention, for driving the delivering means. If a drive spring is used as the drive means, as is preferred, then the spring strength of this drive means can be significantly higher than in the case of a direct drive connection to the delivering means. In particular, such a drive spring can be operated in a smaller range of its spring characteristic than would be possible in the case of a direct coupling.
[0013] Particularly preferably, a working stroke of the drive means is transmitted into a working stroke of the delivering means by the fluid coupling, said working stroke of the delivering means being greater than the working stroke of the drive means. In the case of a pressure or tension spring as the drive means and a piston as the delivering means, the respective working stroke is the stretching or straining of the spring and the distance covered by the piston in dependence on this working stroke. Particularly preferably, the delivering means is formed as a piston and the drive means likewise acts on a piston, designated in the following as a drive piston. In this embodiment, the drive side of the fluid space is formed by a piston area of the drive piston. The piston area of the drive piston is preferably larger than a piston area of a driven piston, wherein the piston area of the driven piston forms the driven side of the fluid space.
[0014] Through this ratio of the two piston areas, a stroke of the drive piston is transmitted into a comparatively larger stroke of the driven piston. Expressed differently, a smaller stroke of the drive piston is required to achieve a given stroke of the driven piston. The working stroke of the drive piston can be kept correspondingly short. The drive means can be operated in a tight range around its optimal operating point. Furthermore, the different-sized piston areas lead to a reduction of force. The force exerted by the drive piston is reduced in accordance with the ratio of the areas of the drive piston and driven piston. This reduction occurs in addition to the reduction of force as a result of the reduction of pressure. The Applicant reserves the right to independently further prosecute the feature of the different-sized piston areas, together with features a) to e) of claim 1.
[0015] The driven piston can form the delivering means directly. The driven piston is, however, preferably another piston.
[0016] In a particularly preferred example embodiment, the fluid space is sub-divided into a first partial space including the drive side and a second partial space including the driven side, and the two partial spaces are connected to each other exclusively by a system of capillaries, if a higher pressure prevails on the drive side than on the driven side of the fluid space. The system of capillaries can be formed by a single capillary or also by a plurality of capillaries.
[0017] The capillary or plurality of capillaries is/are advantageously as long as possible. Its/their length is preferably at least 0.5 m. If a plurality of capillaries are formed, this preferably applies to each of the capillaries. The through-flow rate in long capillaries is less dependent on the diameter of the capillary, as directly follows from the Hagen-Poiseuille Law. According to the Hagen-Poiseuille Law, variations in the diameter due to imprecision in production enter into the through-flow rate in the fourth power. However, with an increasing length of the capillary, its diameter can likewise be enlarged, if the through-flow rate is to remain constant. Larger diameters are on the one hand by their very nature simpler to produce than smaller diameters, and with an increasing size of the diameter, deviations from the desired diameter arise to an increasingly less important extent only. Furthermore, an as high viscosity of the working fluid as possible in the fluid space is preferred.
[0018] The system of capillaries preferably comprises a capillary running spirally, or a plurality of such capillaries. In a preferred example embodiment, the system of capillaries is formed by a single, spiral capillary. A spiral capillary not only has the advantage of a large length, but can also be simply produced. In particular, it can be formed in the form of an external or internal thread on a corresponding surface area, preferably a shell or jacket surface area, of a capillary body. The capillary body with the external or internal thread is preferably placed into or onto another body with a smooth opposite surface area, wherein care must be taken that the threads of the capillary body are sealed against each other on the opposite surface area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will now be described by way of a preferred example embodiment. There is shown:
[0020] [0020]FIG. 1 an infusion device in a longitudinal section;
[0021] [0021]FIG. 2 a capillary in accordance with Detail I of FIG. 1; and
[0022] [0022]FIG. 3 an alternative embodiment of a capillary.
DETAILED DESCRIPTION
[0023] [0023]FIG. 1 shows a longitudinal section of an infusion device.
[0024] A circular cylindrical outer sleeve 3 , together with a sealing piece 9 at a proximal end and a sealing cap 19 at a distal end, forms a casing of the infusion device. A container holder 4 a is held centered in a proximal region of the outer sleeve 3 . A container 1 in the form of an ampoule is accommodated by the container holder 4 a , likewise centered with respect to the central longitudinal axis of the outer sleeve 3 . The container 1 is filled with a product to be injected, for example insulin. A delivering means 2 in the form of a delivering piston is furthermore movably accommodated by the container, in a straight line toward an outlet of the container 1 . A catheter 20 is connected to the outlet of the container 1 in a manner known in its own right.
[0025] An inner sleeve 4 b is arranged in a distal region of the infusion device, concentric with respect to the outer sleeve 3 . In the example embodiment, the container holder 4 a and the inner sleeve 4 b are formed as a one-piece sleeve. The container holder 4 a and the inner sleeve 4 b could also be separate components. However, forming them as one piece simplifies holding them commonly centered in the outer sleeve 3 , as can be directly inferred from FIG. 1 and the subsequent description.
[0026] An inner surface area of the inner sleeve 4 b forms a slide bearing for a driven piston 6 accommodated by the inner sleeve 4 b , said driven piston being connected rigidly to the delivering piston 2 by means of a piston rod 7 . The driven piston 6 and the piston rod 7 are formed as one piece. The piston rod 7 abuts the delivering piston 2 . It could also be firmly connected to the delivering piston 2 ; for example, it could be screwed to the delivering piston 2 . Furthermore, the piston rod 7 can equally be guided into a collar region between the container holder 4 a and the inner sleeve 4 b , for example guided fluid-proof. The driven piston 6 seals toward the inner sleeve 4 b using sealing rings 17 in the manner of piston rings.
[0027] A ring space is formed between the outer sleeve 3 and the inner sleeve 4 b , a drive piston 5 being arranged in said ring space. The drive piston 5 is a ring piston which is slid back and forth, fluid-proof and tight, between the outer sleeve 3 and the inner sleeve 4 b . Sealing rings 15 are accommodated by grooves in an inner surface area of the drive piston 5 and other sealing rings 16 are accommodated by grooves on an outer surface area of the drive piston 5 , each in the manner of piston rings. The drive piston 5 comprises a plane ring area on a distal front face. The drive piston 5 tapers toward the inner sleeve 4 b in the proximal direction. The taper is formed by means of a collar. An opposite area of the infusion device lies opposite the collar, seen in the proximal direction. The opposite area is formed by a distance piece in the form of a distance ring 9 a , which surrounds the container holder 4 a and lies loose on the sealing piece 9 .
[0028] In a ring space between the outer sleeve 3 on the one hand and the container holder 4 a and the inner sleeve 4 b on the other, a pressure spring 8 is accommodated between the two opposing areas, i.e. the collar of the drive piston 5 and the distance ring 9 a , abutting the two areas. By varying the strength of the distance ring 9 a , i.e. by exchanging it, the device can be simply adapted to different pressure springs 8 , to continuously set the operative range of the spring optimally.
[0029] A capillary body 10 is arranged behind the drive piston 5 in the distal direction. The capillary body 10 comprises a proximal ring region and is occluded by a base at its distal end. In the region of its ring body, the capillary body 10 is sealed fluid-proof against the outer sleeve 3 and preferably also against the inner sleeve 4 b . A distal front area of the inner sleeve 4 b pushes fluid-proof against the base of the capillary body 10 via a sealing ring 18 . The capillary body 10 is provided with a aperture opening 14 in the region of a distal opening on the front face of the inner sleeve 4 b which is sealed by the sealing ring 18 .
[0030] An aperture open in one direction only is formed in the capillary body 10 by a reflux valve. The reflux valve comprises a valve ball 11 which is pressed into its fitting within the capillary body 10 in a known way by means of a valve spring 12 . The valve spring 12 is in turn supported on a valve closure 13 .
[0031] A fluid space is formed between the distal front area of the drive piston 5 and a distal front area of the driven piston 6 , said fluid space being occluded fluid-proof by said two pistons 5 and 6 and comprising a first partial space 21 and a second partial space 22 . The two partial spaces 21 and 22 are separated from each other by the capillary body 10 . The fluid space 21 , 22 is completely filled with an incompressible working fluid. A highly viscous oil is preferably used as the working fluid.
[0032] The reflux valve 11 , 12 , 13 only allows a through-flow of the working fluid from the partial space 22 into the partial space 21 , and prevents a through-flow in the other direction.
[0033] The capillary body 10 , together with an inner surface area of the outer sleeve 3 surrounding the capillary body, forms a fluid connection in the form of a system of capillaries. The system of capillaries is shown in Detail I of FIG. 2. It is formed by a single, connected fluid channel, namely a capillary 23 . The capillary 23 , in the form of a multiple thread, encircles the outer surface area of the capillary body 10 in a spiral. In principle, the capillary 23 can also be formed by a single thread. When the capillary body 10 is installed, the capillary 23 connects the two partial fluid spaces 21 and 22 . The inner surface area of the outer sleeve 3 opposite the capillary 23 is simply smooth. The capillary body 10 is guided into the outer sleeve 3 by a slight pressing power. When installed, the “teeth” on the outer surface area of the capillary body 10 , which separate the individual threads of the capillary 23 from each other, press fluid-proof against the inner surface area of the outer sleeve 3 . The teeth of the capillary body 10 are flattened for sealing purposes. The capillary body 10 consists of a softer material than the outer sleeve 3 , in order to improve sealing. For the same purpose, however, the outer sleeve 3 could also in principle be made of a softer material than the capillary body 10 .
[0034] An alternative embodiment of a capillary 23 is shown in FIG. 3. In this case, the capillary 23 is formed in one insert as a straight fluid channel. The insert is held fluid-proof in a receptacle of the capillary body. A bore which extends the capillary 23 of the insert is formed in the capillary body 10 , such that in this embodiment too, a fluid connection is provided between the two partial spaces 21 and 22 by means of a capillary 23 .
[0035] By inserting a distance ring 9 a , all deviations from the corresponding desired values arising in the transmission link from the pressure spring 8 to the driven piston 6 can be simply compensated for. In this way, not only differences in the pressure springs but also for example capillary defects may be compensated for by means of the distance ring 9 a . Compensating is achieved by setting the bias of the pressure spring 8 by means of an easily replaceable distance ring 9 a . There are thus distance rings 9 a of various strengths for various types of devices, and when the device is being assembled, the distance ring which exhibits the optimal strength for compensating is inserted.
[0036] The functionality of the infusion device will now be described:
[0037] In the state shown in FIG. 1, the container 1 is filled with the product and the delivering piston 2 correspondingly assumes its distal position in the container 1 . The driven piston 6 also correspondingly assumes its distal position in the inner sleeve 4 b . In this distal position, the driven piston 6 is ideally occluded by the rear front area of the inner sleeve 4 b , in order to keep the overall length of the device as short as possible.
[0038] In this state of the device, the partial fluid space 22 exhibits its smallest volume. The partial fluid space 23 correspondingly exhibits its largest volume. The driven piston 6 is held in its distal position either directly by the user or preferably by means of a latch. At the same time, the drive piston 5 assumes its proximal position. In this proximal position of the drive piston 5 , the pressure spring 8 is tensed between the two areas formed by the collar area of the drive piston 5 and the distance ring 9 a.
[0039] For subcutaneously administering the product, an injection needle arranged at the proximal end of the catheter 20 is inserted, and the latch on the driven piston 6 or the piston rod 7 respectively is released. Under the pressure of the pressure spring 8 , a fluid pressure is built up in the partial fluid space 21 via the drive piston 5 . This fluid pressure can only be decreased by the capillary 23 . Under the pressure of the drive piston 5 , fluid flows out of the partial fluid space 21 , through the capillary 23 , into the partial fluid space 22 . The driven piston 6 is moved in the proximal direction by the pressure building in the partial fluid space 22 . The partial fluid space 21 thus forms a drive side and the partial fluid space 22 a driven side of the fluid space 21 , 22 as a whole. More precisely, the drive side is formed by a piston area of the drive piston 5 facing the partial fluid space 21 , and the drive side by a piston area of the driven piston 6 facing the partial fluid space 22 .
[0040] In the example embodiment, a pressure reducing means is formed by the capillary body 10 , the outer sleeve 3 and the capillary 23 formed by their co-operation. A constructively determined drop in pressure is effected by said pressure reducing means. Due to the drop in pressure generated, it is possible to use a stronger pressure spring 8 for driving the delivering piston 2 than would be possible in an unchoked drive.
[0041] Moreover, the piston area of the drive piston 5 is larger than the piston area of the driven piston 6 . Correspondingly, a stroke of the drive piston 5 effects a comparatively greater stroke of the driven piston 6 . The driven piston 6 in turn acts directly on the delivering piston 2 by means of the rigid piston rod 7 . Correspondingly, a complete stroke of the driven piston 6 corresponds to the stroke of the delivering piston 2 . The stroke of the delivering piston 2 is in turn determined by the conventionally used containers 1 . The complete working stroke of the delivering piston 2 , which corresponds to a complete delivery of the contents of the container 1 , compares with a by comparison substantially shorter working stroke of the drive piston 5 and thus of the pressure spring 8 .
[0042] The concentric arrangement of the two partial fluid spaces 21 and 22 of the overall fluid space 21 , 22 is also constructively interesting. Through this arrangement, the overall length of the device can be kept short.
[0043] To drive it, the delivering piston 2 is charged with a pressure of about one bar, i.e. it exerts such a pressure on the contents of the container 1 . The fluid coupling is correspondingly formed to transmit the force of the pressure spring 8 from the drive side of the fluid space 21 , 22 onto the driven side. This is substantially achieved by the pressure reducing means formed by the outer sleeve 3 , the capillary body 10 and the capillary 23 , and by the size ratio of the two piston areas of the pistons 5 and 6 .
[0044] After the product has been delivered, for example after the device has been completely emptied, the container 1 can be re-filled to administer product again, or preferably replaced with a new, filled container. Before replacing the container, the delivering piston 2 is retracted by means of the piston rod 7 to the starting position shown in FIG. 1. In the starting position, the piston rod 7 is latched by a suitable locking means. In the course of retracting, the driven piston 6 pushes the fluid out of the completely filled partial fluid space 22 into the partial fluid space 21 . In this way, the fluid flows out of the internal space of the inner sleeve 4 b , through the opening 14 in the base of the capillary body 10 , and via a small intermediate space between the sealing cap 19 and the capillary body 10 to the reflux valve 11 , 12 , 13 . Under the pressure of the fluid in the partial fluid space 22 , the reflux valve opens and the fluid flows through the through-flow formed by the reflux valve and into the partial fluid space 21 . Here, the pressure of the pressure spring 8 has to be overcome to advance the drive piston 5 in the proximal direction and ultimately into the starting position shown. The device is then ready to deliver product again.
[0045] In the foregoing description a preferred embodiment of the invention has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen and described to provide the best illustration of the principals of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly, legally, and equitably entitled.
List of Reference Numerals
[0046] [0046] 1 container, ampoule 2 delivering means, delivering piston 3 casing, outer sleeve 4a container holder 4b inner sleeve 5 drive piston 6 driven piston 7 piston rod 8 drive means, drive spring, pressure spring 9 sealing cap 9a distance piece 10 separating body, capillary body 11 valve ball 12 valve spring 13 valve closure 14 aperture opening 15 sealing rings 16 sealing rings 17 sealing rings 18 sealing ring 19 sealing cap 20 catheter 21 partial fluid space 22 partial fluid space 23 fluid connection, system of capillaries, fluid channel, capillary
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The invention relates to a device for administering an injectable product, comprising:
a) a casing ( 3 );
b) a container for said product accommodated by said casing ( 3 )
c) a delivering means ( 2 ) for delivering product out of said container ( 1 );
d) a drive means ( 8 ); and
e) a transmission link via which said drive means ( 8 ) drives said delivering means ( 2 ).
The device is characterised in that:
f) a fluid space ( 21, 22 ) for an incompressible fluid and
g) a pressure reducing means ( 3, 10, 23 ) are provided in said transmission link;
h) wherein said fluid space ( 21, 22 ) can be impinged on a drive side by pressure from said drive means ( 8 ) and said pressure reducing means ( 3, 10, 23 ) reduces a fluid pressure generated by said drive means ( 8 ) toward a driven side of said fluid space ( 21, 22 ).
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RELATED APPLICATIONS
[0001] This application claims the benefit of prior filed Provisional Application No. 60/466,688.
BACKGROUND OF THE INVENTION
[0002] An ion channel is a pore formed of one or more protein subunits in the cell membrane. These pores allow the movement of ions in (influx) and out (efflux) of the cell. These channels are generally selective for the movement of a specific ion. Important to the present invention, is the fact that there are ion channels which are selective for the movement of chloride ions. The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene encodes a cAMP activated-chloride channel that is required for proper function of secretory cells in the airway, intestine, pancreas, liver, lungs, and reproductive tract. The CFTR channel is an outward rectifying chloride ion channel. That is, it allows chloride to flow out of the cell. Mutations of such genes are responsible for a variety of diseases, particularly when the mutation results in any loss of channel function.
[0003] Channel dysfunction arising from the CFTR gene is most notably associated with the disease Cystic Fibrosis, but it has also been associated with forms of male infertility, polycystic kidney disease, secretory diarrhea, chronic obstructive pulmonary disease, asthma, bronchitis, emphysema, and pneumonia. Thus, chloride channels are a potential target for drug candidates. For example, by using pharmacological intervention to restore normal CFTR channel activity, one can reduce/reverse the effects of a malfunctioning CFTR channel. It has been found that even a 5-10% improvement in chloride conductance is believed to have substantial therapeutic value. Therefore, the need exists for the invention of a high throughput screening (HTS) assay that will effectively and rapidly screen for modulators of chloride channel activity. The present invention was developed using the CFTR channel as a test case, however, the assay could be applied to several other chloride channels.
[0004] Current technologies for measuring halide conductance (such as fluorescent indicators) pose problems such as: high background noise, half-life problems, quenching effects, and pH sensitivity. Another technology which shows promise to overcome these problems is the automated patch-clamp, which are now commercially available. However, these systems have definitely not produced as promised in that their throughput is still quite low. Another disadvantage of these systems is the fact that they are only measuring a single cell. It would be more physiologically relevant to measure the activity of a population of cells since cells generally exist in a population inside living organisms. The present invention described here gives an effective HTS method to determine chloride channel activity using atomic absorption spectroscopy. The ion channel activity of a population of cells is measured using a method that overcomes the limitation of the technologies mentioned above. The method and techniques involved will be made clear by way of example using CFTR as the candidate channel.
SUMMARY OF THE INVENTION
[0005] A method is provided to screen for modulators of chloride ion channels using atomic absorption spectroscopy. Flame atomic absorption spectroscopy (FAAS) or graphite furnace atomic absorption spectroscopy (GFAAS) could be used. In one embodiment, cells expressing the chloride ion channel of interest are surrounded with a solution that activates the chloride channels. Varying amounts of potential activators or inhibitors are added to assess their activity. Next, the supernatant is removed from the cells and a known amount of silver ions is added to this solution as silver nitrate. It is important to note that the amount of silver ions that is added is in excess of the chloride ions that are present, the reason for which are described below. Silver ions complex with the chloride ions forming the solid silver chloride. This solid precipitates and can be separated from the liquid phase. Next, the remaining silver ions left in solution are measured using atomic absorption spectroscopy and through well known theory and calculations the amount of chloride that came out of the cells can be determined. Briefly, the chloride present reduces the silver concentration and this reduction can be used to calculate the amount of chloride that came out of the cells. It is important to note that the chloride is not measured directly since measuring chloride ions using atomic absorption spectroscopy is not feasible.
[0006] An advantage of this invention is that the experimental methodology described herein provides a way for researchers to accurately determine the therapeutic effects of chloride channel modulating compounds for the purpose of drug discovery. Chloride channels are extremely important to several physiological processes and therefore it is very important to be able regulate or restore the activity of a malfunctioning channel.
BRIEF DESCRIPTION OF DRAWINGS
[0007] Further features and advantages of the invention will be apparent from the following detailed description, given by way of example, of a preferred embodiment taken in conjunction with the accompanying drawing, wherein:
[0008] [0008]FIG. 1 is a block diagram of the procedure for carrying out the chloride efflux assay.
[0009] [0009]FIG. 2 is a depiction of the chemical reaction that occurs during the silver chloride precipitation.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Referring to FIG. 1 and FIG. 2, a description of a preferred embodiment of the invention is shown. Specifics of the invention will be made known by way of example using the CFTR channel as an example.
TISSUE CULTURE
[0011] The cells used for the analysis may be any cell line in which the cells express outwardly rectifying chloride channels, such as the CFTR channel. Common cell lines that may be used include but are not limited to: chinese hamster ovary (CHO) cells, human embryonic kidney (HEK) cells, or fibroblast cell lines. The cells can express the chloride ion channel endogenously or the expressed ion channel can be the result of transfection genes. This assay was developed using a CFTR expressing cell line (T-84); however, its application is not limited to this family of chloride channels.
[0012] The cells expressing the ion channel of interest are incubated and cultured by traditional means, all of which are well known to those individuals skilled in the art. For the CFTR assay developed using the T-84 cell line, cells were grown in 1:1 Dulbecco's modified eagle's media (DMEM) and Ham's F-12 medium, supplemented with 10% fetal calf serum (FCS) at 37° C. celsius , in 5% CO 2 . A digestive enzyme, such as trypsin, is used to break the protein bonds between the cells and the culture vessels. The cells are removed from the culture vessels and were plated at a density of approximately 50,000 cells/well in 96-well microplates and incubated at 37° C., 5% CO 2 until 80-90% confluency is attained. The 96-well plates typically have some type of special surface treatment which allows for proper cellular adhesion. The cells are allowed to incubate at 37° C. for a minimum 12-hour period (typically 18 hours). The exact experimental incubation period will depend on the desired final cell density, the type of cell line used, and on the level of ion channel expression. The purpose of this incubation period is to allow the cells to grow, express the ion channels, multiply to increase the cell density in the microplate, and to allow cells to adhere to the surface of the microplate wells.
ASSAY
[0013] The cell monolayer on the bottom of each well is then washed three times with a wash buffer. The wash buffer does not contain any chloride ions. It is an isotonic solution which serves to remove any extra-cellular chloride ions. These types of steps can be done using either an auto-sampler or it can be done manually, allowing the injection and subsequent aspiration of buffer solution into each sample well. This buffer also contains a nutritional supplement such as glucose to help feed the cells. The chemicals and biological substances used in this buffer are all commercially available and familiar to persons skilled in the art. Other cell lines may require other ingredients and/or additional salts to create the best condition for the health of the cells.
[0014] Channel activation and testing of compounds for activity on the ion channels occurs next. At this point the activation buffer is added to the cell monolayer. This buffer is the same as the wash buffer except it contains the following additions:
[0015] (a) A known channel activator (in the case of the t-84 cell line the agonist forskolin was used).
[0016] (b) the test compound in varying concentrations, being the candidate compound of interest which may serve to further activate the channel, or inhibit channel activity.
[0017] An agonist is a specific compound that acts by binding to the receptor site of the ion channel causing a reaction that mimics a natural chemical messenger or a membrane charge stimulus. The effect of the agonist forskolin on the CFTR channel is activation of the channel leading to chloride efflux. This type of up regulation of channel activity generates a window of detection, such that if you added a compound which blocked CFTR activity that you would see a reduction in chloride efflux. This application can also be manipulated to detect channel activators. For example, the activity of a very weak agonist drug may be elucidated by performing this assay at increasing concentrations of a test compound in the presence of a low fixed concentration of Forskolin. Therefore, this drug discovery application may be used to screen for chloride channel agonists, antagonists, and neutral candidate compounds which have no appreciable effect.
[0018] The control samples include, but are not limited to, the following:
[0019] (a) a negative control indicating the basal chloride ion flux in the absence of any known agonist or test compound; and
[0020] (b) a positive control indicating the chloride ion flux in a medium containing a known agonist, but in the absence of any test compound.
[0021] To determine the activity of a compound the prepared unknown and control samples (in activation buffer) are added to the cell monolayer. This incubation period may vary experimentally, from seconds to several minutes, depending on the cell line. After this incubation period, the cells are then isolated from the extracellular solution. Using the T84 cell line expressing CFTR, the following steps were taken to complete the assay. These steps may need to be modified slightly for other cell lines. To 200 μL of the extracellular solution, 30 μL of a silver solution (50 ppm silver as silver nitrate) was added. As per FIG. 2, the silver ions present react with the chloride ions to form the solid silver chloride. This precipitate was allowed to settle for 3-4 hours. The free silver ions in this solution were then analyzed using atomic absorption spectroscopy (best results were achieved using the ICR series from Aurora Biomed, Vancouver). Using the ICR 8000 or the ICR 12000 coupled with automated liquid handling techniques allows the assay to be done in a high throughput format.
[0022] Halide ions, including chloride, are known to be a highly reactive ion species. Referring to FIG. 2, the chemical reaction between chloride and silver immediately produces a stable silver chloride solid that precipitates out of solution. This theory is well known and has been studied extensively. With an understanding of this theory one can calculate the concentration of chloride that was in the supernatant after the activation period, which would have been due to the chloride channel activity. This calculation is relatively simple for one skilled in the arts and takes into account such things as the solubility constant of silver chloride, the amount of silver ions added, and the exact volumes involved. The reader is encouraged to consult basic chemistry texts which cover such topics as equilibrium, solubility, and thermodynamics.
AAS
[0023] Atomic absorption spectroscopy (AAS) is a well-known technique for elemental chemical analysis. Flame atomic absorption spectroscopy (FAAS) uses a flame furnace to first vaporize the solute ions and then measure the concentration of gas-phase atoms using the absorption of light. The detection level of silver using the ICR 8000 (Aurora Biomed) is very low, with a dynamic range of 0.02 ppm to 4 ppm. Such automated instrumentation increases the throughput of assays by using microsyringe autosampling. A graphite furnace atomic absorption spectroscopy (GFAAS) operates on a similar premise but has even greater sensitivity than FAAS. However, GFAAS is only appropriate with extremely low volumes of sample. Either method can be applied to accurately measure chloride flux activity through the ion channel using the silver chloride precipitation method described above.
[0024] The concentration of silver ions remaining in solution is thereby measured with an atomic absorption spectrometer. Therefore, we claim an invention that is able to determine the activity of the chloride channel.
DATA PROCESSING
[0025] The method described here can be used to determine whether a candidate compound, that is designed specifically to target chloride channels, is an antagonist (channel blocker), an agonist (channel activator), or has no effect on its activity (neutral). For example, if the addition of the test compound results in a lower concentration of chloride ions than the basal flux, then this would indicate that the compound is an activator of chloride channels, by increasing the efflux of ions. Alternatively, if the test compound results in a higher concentration of chloride ions in the cell than found basally, it indicates that the compound is a blocker of the chloride channel, by decreasing the efflux. If the addition of a test compound results in no more or no less chloride ions than in the sample without the addition of the compound, then this would indicate that the compound is a non-blocker and non-activator of the chloride channel, or neutral in effect on the ion flux. Furthermore, this application is useful in drug safety screening to determine whether drugs for other targets may also have unwanted or adverse effects on chloride channel activity.
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A method for screening of potential modulators of chloride ion channels is described. Flux of chloride is measured indirectly by first precipitating the chloride which has moved out of the cell by addition of an excess of silver ions. Then, the concentration of silver ions left in solution is measured using atomic absorption spectroscopy. This value is then used as a measure of the amount of chloride flux that has occurred.
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BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART
The present invention relates to the field of blades, particularly fan blades, intended for turbojets, particularly of the aeronautical type.
The turbojet conventionally comprises a compressor, a combustion chamber and a turbine. The purpose of the compressor is to increase the pressure of the air supplied to the combustion chamber. The purpose of the turbine is to drive the rotation of the compressor by tapping off some of the pressure energy of the hot gases leaving the combustion chamber and converting it into mechanical energy.
A turbojet may be of the “bypass” type, that is to say one through which two air flows pass, a primary flow and a secondary flow. The primary flow is produced by elements that make up a single flow turbojet to which one or more additional turbines are added in order to drive a compression stage, the fan. This fan is equipped with large-sized blades, the fan blades, which produce the secondary flow. The fan slightly increases the pressure of the gases passing through it but, because its diameter is large, the energy produced for thrust is high.
One well-known example of a turbojet with a fan, also known as a turbofan is the CFM56 fitted to numerous airplanes across the world for a number of decades now. The successive series of the CFM56 have seen a gradual decrease in the number of fan blades.
Decreasing the number of fan blades on a turbojet is advantageous insofar as it allows a significant reduction in the mass of the turbojet and a reduction in procurement and maintenance costs. This reduction in the number of blades must not, however, be made at the expense of turbojet performance. Preferably, an increase in the chord length of the blades should be avoided in order to limit the size, and thus the mass, of the turbojet.
Gradually reducing the number of blades involves increasing the relative pitch better known in English as the “pitch to chord ratio” and, for the same chord length, increasing the inter-blade distance, that is to say the distance separating two consecutive blades.
The pitch to chord radio is defined as the ratio s/C where:
s represents the inter-blade pitch (s=2πR/N) N being number of blades on a bladed disk, and C represents the chord of the profile at the radius R considered over the height of a blade, the chord C representing the length of the segment connecting the leading edge to the trailing edge of a blade.
SUMMARY OF THE INVENTION
The objective of the present invention is to provide a fan blade the features of which will enable the number of fan blades to be reduced while at the same time providing satisfactory performance.
To this end, the present invention relates to a bypass turbojet fan blade which comprises a plurality of aerodynamic parts which are superposed in a radial direction Z and in which the number of aerodynamic profiles varies from one aerodynamic part to the other.
One aerodynamic part has aerodynamic properties imparted by at least one aerodynamic profile, each aerodynamic profile comprising a suction face, a pressure face, a leading edge and a trailing edge.
The radial direction z corresponds to the essentially longitudinal direction of a blade. It is usually termed the radial direction by the person skilled in the art because this direction corresponds to a radius leading from the axis of rotation X of the turbojet on which said blade is customarily positioned during operation.
As a preference, the fan blade according to the invention comprises a lower aerodynamic part and an upper aerodynamic part which is superposed in a radial direction Z, each aerodynamic part having at least one aerodynamic profile, the number of aerodynamic profiles of the upper aerodynamic part being greater than the number of aerodynamic profiles of the lower aerodynamic part.
Within the meaning of the present invention, the upper aerodynamic part denotes that part of the blade furthest from the axis of rotation X of the turbojet on which said blade is customarily positioned in operation and the lower aerodynamic part denotes that part of the blade closest to the axis of rotation X of the turbojet.
As a preference, the lower aerodynamic part has a single aerodynamic profile and the upper aerodynamic part has at least two aerodynamic profiles.
As a preference, the aerodynamic profiles of the one and the same aerodynamic part are identical.
The fan blade according to the invention may further comprise a platform separating the lower aerodynamic part and the upper aerodynamic part. This platform may constitute an air splitter, particularly to separate the primary flow from the secondary flow in a bypass turbojet.
The invention also relates to a turbojet comprising at least one fan blade fixed, either by its lower end to a hub, or by its upper ends to a rotary casing.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages and features of the invention will become apparent from reading the detailed description which follows, with reference to the attached figures, provided by way of nonlimiting examples, in which:
FIG. 1 depicts a front view of fan blades according to the invention positioned on a hub;
FIG. 2 depicts a perspective view of fan blades according to the invention, positioned on a hub;
FIG. 3 depicts a side view of a fan blade according to a first embodiment of the invention; and
FIG. 4 depicts a side view of a fan blade according to a second embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 depict three fan blades 1 according to the invention positioned on a hub 2 of axis of revolution X. The axis of revolution X of the hub 2 coincides with the axis of rotation X of the turbojet.
The fan blade 1 according to the invention, which extends radially from the axis X, comprises a lower aerodynamic part 11 and an upper aerodynamic part 12 . The lower aerodynamic part 11 consists of one aerodynamic profile.
In the example illustrated in FIGS. 1 and 2 , the upper aerodynamic part 12 of the fan blade 1 comprises two aerodynamic profiles 14 . Alternative forms of embodiment of the invention with a fan blade 1 comprising more than two aerodynamic profiles 14 are also conceivable. A fan blade 1 comprising three aerodynamic profiles 14 is also advantageous. A blade such as this is depicted in dotted line in FIG. 2 . These aerodynamic profiles 14 are preferably identical and directed radially.
When the upper aerodynamic part 12 of the fan blade 1 comprises at least two aerodynamic profiles, the number of blades increases and this appreciably reduces the pitch to chord ratio in the upper aerodynamic part 12 of the blade. The pitch to chord ratio at the upper end 16 of the fan blade 1 therefore has more limited values for which the compression ratio is satisfactory.
By keeping a higher pitch to chord ratio on the lower aerodynamic part 11 of the fan blade, it is possible to safeguard against possible aerodynamic lock problems that arise when it becomes difficult to provide the primary flow with a sufficiently high flow rate.
A platform 10 separates the lower aerodynamic part 11 from the upper aerodynamic part 12 of the fan blade 1 . This platform 10 connects the upper end of the aerodynamic profile 13 to the lower ends of the other two aerodynamic profiles 14 . In order to cause the least possible disturbance to the flow of the primary and secondary flows, this platform 10 needs to lie at a point on the fan blade 1 where the primary and secondary flows form. As a preference, it itself constitutes an air splitter dividing the primary flow from the secondary flow.
As a preference, the platform 10 has an aerodynamic shape so as to guide the flow of air to which it is liable to be subjected.
The platform 10 may also be of the contiguous type, that is to say that it has a shape capable of espousing the complementary and identical shape of an adjacent platform 10 when the fan blades 1 from which they hang are duly positioned on a hub 2 .
According to a first embodiment depicted in FIG. 3 , the fan blade 1 is fixed by its lower end 15 to the hub 2 , its upper ends 16 being free. Attachment may be performed using techniques known to those skilled in the art such as, for example, collaboration between a tenon situated at the lower end 15 and sliding in a mortise slot in the hub 2 .
Advantageously, the axial size of the aerodynamic profiles 13 and 14 may be substantially identical, for example where they meet one another. Thus, for example, at the platform 10 , the axial size of an aerodynamic profile 13 is identical to the axial size of an aerodynamic profile 14 . As a result, at the platform 10 , the leading edges of the aerodynamic profiles 13 and 14 are axially aligned. Likewise, at the platform 10 , the trailing edges of the aerodynamic profiles 13 and 14 are also axially aligned.
In this first embodiment, the fan blade 1 is conventionally subjected to tensile stresses in a radial direction Z with respect to the axis X of the hub 2 .
According to a second embodiment depicted in FIG. 4 , the fan blade 1 is fixed by each of its upper ends 16 to a rotary casing 3 of axis X, its lower end 15 possibly being free. The rotary casing 3 is in the form of a shell ring surrounding the fan and secured to the latter. The assembly formed by the rotary casing 3 and the fan blades 1 can be rotated about the axis X. Rotational drive of the assembly is performed through a system of gears 4 mechanically connecting the rotary casing 3 to the turbine of the turbojet.
This second embodiment also has the objective of eliminating the clearance between the blades and the casing 3 surrounding them.
In this second embodiment, the fan blade 1 is subjected to compressive stresses. This configuration is advantageous because a mechanical component is better able to withstand compressive stresses than tensile stresses.
Furthermore, the special shape of the fan blade 1 according to the invention contributes to its good mechanical integrity. As the fan rotates, centrifugal forces push the aerodynamic profile 13 and the platform 10 radially outward toward the rotary casing 3 . The stresses exerted by these components 10 and 13 are advantageously spread over the two aerodynamic profiles 14 of the upper aerodynamic part 12 of the fan blade 1 . The risk of the fan blade 1 buckling, that is to say of lateral deformation due to a normal compressive load, is therefore low.
Attaching a fan blade 1 via the upper aerodynamic part 16 also presents advantages in terms of turbojet efficiency because the clearance between the upper end 16 of a fan blade 1 and the rotary casing 3 becomes nonexistent. Thus, the loss of efficiency due to this clearance in more conventional designs of turbojet disappears.
Furthermore, this type of attachment advantageously makes it possible to reduce the mass of the turbojet by reducing the hub Ri/Re ratio, that is to say the ratio between the internal radius Ri and the external radius Re, Ri being distance to the point on the leading edge of the blade 1 closest to the axis (X) of the turbojet, and Re being the distance to the point on the leading edge of the blade 1 that is furthest from said axis (X). Because the hub 2 is no longer used, in this second embodiment, to attach the blades, the internal radius can be small or even zero. In one extreme case, the turbojet may have no hub 2 for the fan blades 1 . For the same external radius Re, the mass of the hub 2 can thus be small or even zero. The mass of the turbojet is thus reduced.
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The present invention relates to the field of blades, particularly fan blades, intended for turbojets, particularly of the aeronautical type. Its objective is to provide a fan blade the features of which will enable the number of fan blades to be reduced while at the same time providing satisfactory performance. According to the invention, the fan blade comprises a plurality of aerodynamic parts which are superposed in a radial direction Z and the number of aerodynamic profiles varies from one aerodynamic part to the other.
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This application is a continuation application of Ser. No. 736,293, filed 20 May 1985, now abandoned, which is a continuation of Ser. No. 576,203, filed 2 Feb., 1984 now abandoned, which is a continuation of Ser. No. 229,510 filed 29 Jan., 1981, now abandoned, for DOOR STRUCTURE FOR GARAGE DOORWAYS AND METHOD OF MAKING SAME, invented by Robert A. Martinez et al.
TECHNICAL FIELD
This invention relates to a novel door structure that is particularly suited for closing a garage doorway and to a method of making same.
BACKGROUND ART
Garage doors currently in use, in general, are made up of a plurality of panels arranged one above another and hingedly connected at meeting top and bottom rails to pivot relative to one another as the door is raised and lowered. The construction of these panels includes a relatively large number of wooden pieces including top and bottom wooden rails and upright wooden stiles which are joined in a rectangular framework at tongue and groove joints, together with a plurality of hardboard sheets that fit into inside grooves formed in the wooden rails and intermediate wooden stiles to close the central area of the rectangular framework.
Among the problems encountered with such garage door structures is the unavailability of suitable wood, the cost of wood, the tendency of wood to warp, the maintenance requirements for painted wood, and a strength deficiency in wooden rails. This prior art garage door construction also involves considerable cutting, a number of edge shaping steps, and relatively complex machinery to assemble and fasten the pieces into a completed panel.
DISCLOSURE OF INVENTION
In accordance with the present invention there is provided a door structure characterized by a preformed, weather-resistant panel, preformed, weather-resistant top and bottom strip metal rails of a special configuration mounted thereon, and a backing structure such as upright wooden stiles disposed on the back face of the panel connected at upper and lower ends to opposed, rearwardly extending, fastening flanges on the strip rails to interconnect the panel, rails and stiles as a simple, strong, unitary door structure that is readily assembled in different sizes and shapes. A single top and bottom rail extends along two or more of the panels arranged side by side and a flexible cover molding covers the space between adjacent side portions.
BRIEF DESCRIPTION OF DRAWINGS
The details of this invention will be described in connection with the accompanying drawings, in which:
FIG. 1 is a front elevation view of a door structure embodying features of the present invention;
FIG. 2 is a rear elevation view of the door structure shown in FIG. 1;
FIG. 3 is a sectional view taken along lines 3--3 of FIG. 1;
FIG. 4 is a sectional view taken along lines 4--4 of FIG. 1;
FIG. 5 is an enlarged sectional view of a portion of a panel shown in FIG. 4 with more detail on preferred types of materials and connections between parts for some applications;
FIG. 6 is a front elevation view of another form of door structure embodying features of the present invention and using two groups of the panels connected side by side;
FIG. 7 is a sectional view taken along lines 7--7 of FIG. 6; and
FIG. 8 is an enlarged sectional view of an intermediate molding used in the dual panel arrangement shown in FIGS. 6 and 7.
DETAILED DESCRIPTION
The garage door 10 shown in FIGS. 1-5, which is particularly suited for closing a conventional 8-foot garage doorway, includes four identical panels, each designated by the numeral 11, that are stacked or arranged one above the other and disposed in a common plane.
A metal top rail 16 is mounted oh the top edge of each panel 11 and extends the full length thereof and a metal bottom rail 17 is mounted on the top edge of each panel 11 and extends the full length thereof.
A plurality of laterally spaced upright backing members or stiles 19 are mounted on the back of the panel. Conventional garage door hinges 21 mount on the stiles 19 to pivotally join adjacent of the panels together at meeting rails to pivot as the door is raised and lowered in a conventional manner. For the door shown there are three hinges for joining two panels together, one at each end and one in the middle.
The term "preformed, weather-resistant" as used herein means that the part is made weather-resistant prior to assembly and does not need to be painted or the like.
A structure that has been found particularly suitable for providing a preformed, weather-resistant panel is a mat-formed phenol bonded wood particle board core 11a having an overlay sheet 11b on the front surface and an overlay sheet 11b on the back surface made of a phenolic resin impregnated fiber and sold by the Cladwood Company under the brand name CLADWOOD. In the manufacture of the panel, particles or chips of wood, phenolic type resins, and a fiber overlay are integrally fused by a special process into a composite unit. This panel is preformed with the design therein, is weather-resistant, and is further characterized as a medium density particle board made of coarse wood chips that is substantially impervious to moisture. A preferred thickness for garage doors is 3/8 inch board.
Each panel 11 shown is formed from a generally flat sheet of material with four identical laterally spaced surface designs, each designated A, formed therein. The design shown comprises a raised outer frame section 31 of rectangular shape and a raised center section 32 of rectangular shape that extend in front of all of the other front surfaces of the panel. The latter section 32 extends forwardly beyond the remainder of the front face of the panel.
The top edge portion of the panel 11 is undercut along the back at 36 and this undercut extends the full length thereof to provide a top edge portion of reduced thickness that is of substantially uniform thickness throughout its vertical extent to provide a snug fit for the channel-shaped cap section fitting thereon. Similarly, the bottom edge portion is undercut at 37 and this undercut extends the full length thereof to provide a bottom edge portion of substantially uniform thickness throughout its vertical extent. Since the metal channel-shaped cap sections hereinafter described can be made of a substantially uniform width complementing that of the edge portions of the panel, a close friction fit is provided between these two parts.
The top rail 16 has an inverted channel-shaped top cap section 41 that has an interior space of uniform width throughout its vertical extent and is sized to be complementary to the edge portion of the panel to nest snugly over the top edge portion of the panel. Top rail 16 further has a foldback section 42 that extends back from a bend 43 and along the back leg within the top recessed area 36 in the panel, a flat fastening flange section 44 that projects rearwardly from and in a plane above the base of the cap section 41 to form a forwardly stepped-down top surface 45 along the top edge of the panel, and a raised rear flange portion 46 that extends up and forwardly from the rear marginal edge of the fastening flange section. The raised rear flange portion includes a rear curved section 46a and a rear flange section 46b.
A screw fastener 48 is shown extending through a hole in the fastening flange section 44 and into the end of the stile 19 to secure the top edge strip to the backing member and in turn to the panel. Preferably two screw fasteners per stile are used at both the top and bottom ends. A preferred material for the stile 19 is wood and a preferred size for the cross section is one inch by two and one-half inches.
The bottom rail 17 has a channel-shaped bottom cap section 51 that nests snugly over the bottom edge portion of the panel in a friction-fitting relation, as does the top cap section, with a flat bottom fastening flange section 54 that extends rearwardly from the rear leg of the channel section, the cap section 51 being a forwardly downturned bottom surface 55 that is complementary to, seats on, and overlaps with the top surface 45 above described of the next lower panel, together with a raised rear flange portion 56 that extends up and forwardly from the rear end of the fastening section 54.
Rear flange portion 56 includes a rear curved section 56a and a rear flange section 56b. The rear flange sections 46b and 56b of adjacent or meeting rails provide substantially horizontal contact surfaces and form a recessed area outwardly of the associated fastening flange section.
A screw fastener 58 is shown extending through a hole in section 54 and into the end of the stile 19 to secure the end of the stile to the bottom rail and in turn to the panel.
As best seen in FIG. 6, the abutting bottom and top rails have the rear flange sections opposite one another and the cap sections opposite and in line with one another. The raised rear flange portions of the rails form a space that accommodates the heads of the fastening screws and the raised rear flange portions and cap sections of adjacent panels. Preferably the top and bottom rails are made by roll-forming a single piece of galvanized steel strip material such as 18-gauge.
In a preferred construction for some applications a construction adhesive is applied to the edge portions and inside the cap sections of the rails and also between the back of the panel and the stile 19 for added strength.
Referring now to FIGS. 6-8, to accommodate wider door spaces such as a conventional 16-foot garage doorway, two of the above panels 10 are connected to form a wider garage door, generally designated by numeral 60. In this form of the invention two groups of the panels 11 are connected side by side by one-piece top and bottom rails 16 and 17 and a relatively thin cover molding 62, preferably of extruded plastic, fits over the abutting edge portions and extends along both back and front surface areas.
The cover molding 62, as shown in more detail in FIG. 8, has an outer strip portion 63 that forms one leg for two back to back channel portions 65 and 64 connected at adjacent ends to the outer strip portion 63 and extending along diverging angles to provide a V-shaped gap 66 between the opposed channel structure that allows flexure between the two side by side garage doors and covers the gap therebetween.
As best seen in FIG. 5, the top edge strip 16 and bottom edge strip 17 are continuous for the full length of both end to end panels 11, and the molding 62 has its upper end abutting flush with the top edge strip 16 and the lower end abutting flush with the bottom edge strip to provide a neat appearance.
A preferred procedure for assembling the above described door structure is as follows:
(1) The top and bottom edge strips are placed on the top and bottom edges of the panel and a construction adhesive may be applied to abutting surfaces.
(2) The stiles are positioned and metal screws are threaded via the holes in the fastening flanges into the ends of the stiles. A construction adhesive may also be applied between the panel and stiles prior to assembly.
INDUSTRIAL APPLICABILITY
The exterior parts of the above described door structure have been found to be highly weather-resistant, and the parts are readily assembled in a variety of sizes to meet a variety of garage door applications.
Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.
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Door structure particularly suited for closing garage doorways and a method of making same include top and bottom preformed, weather-resistant metal rails (16, 17) on a single-piece, preformed, weather-resistant panel (11), together with stiles (19) along the back of the panel fastened at the ends to opposed fastening flange sections of the rails to form a strong unitary structure that is readily joined by conventional hinges into a sectional garage door. Two or more of the above described doors are joined side by side by single top and bottom rails and a flexible cover molding (62) adjacent inner ends for closing wider garage doorways.
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FIELD OF THE INVENTION
The present invention relates generally to the field of communications and particularly to digital cellular communications.
BACKGROUND OF THE INVENTION
U.S. digital cellular communications uses digitized voice and data signals for communication between a mobile telephone and a base station. When the mobile moves, it may encounter degraded communication channels due to noise and multipath distortion; both noise and distortion varying with time. The multipath distortion is due to a signal being received by the mobile at different times when it bounces off buildings and terrain. Multipath channels can cause intersymbol interference (ISI) that can be removed with an adaptive equalizer, a specific type of an adaptive filter.
A typical adaptive filter is illustrated in FIG. 1. The input signal (106) is processed by the adaptive filter (101), producing the adaptive filter output signal (102). The output of the filter is then substracted (105) from a reference signal (103), to produce an error signal (104). This error signal (104) is used by an adaptive algorithm with an update coefficient, μ, in the adaptive filter to update the filter coefficients. The update coefficient is also referred to as a tracking coefficient or memory coefficient. It is assumed that the memory of the adaptive algorithm increases as the value of μ increases.
The update coefficient controls the memory of the adaptive algorithm and its determination is a trade-off between the rate that the filter can track the changing channel characteristics and the amount of noise averaging that will be accomplished by the adaptive algorithm. As the adaptive algorithm memory is shortened, the algorithm is better able to track time variations in the communication channel but will become more sensitive to noise on the communication channel. If the coefficient is chosen to filter out more noise, then the filter's channel tracking capability will be reduced.
The adaptive algorithm can be a Kalman, Recursive Least Square, or Least Mean Square (LMS) algorithm. The typical goal of the adaptive algorithm is to minimize the mean square value of the error signal (104). This value is typically designated mean square error (MSE).
FIGS. 2A, B, and C illustrate the three possible classes of adaptive filter operating environments. FIG. 2A is a time invariant system in a noisy environment. In this case, the total MSE, designated E T , comes only from the noise, E n , in FIG. 2A since the system is not time varying. The total MSE is proportional to μ.
FIG. 2B is a time varying but stationary system in a noisy environment; a stationary system having higher order signal statistics that do not change over time. In this example, E T (203) consists of the sum of two independent components, the lag error (201) and the noise (202). The lag error (201) is due to the filter attempting to track the time varying system. The lag error (201), designated E-lag, is inversely proportional to μ. The noise component (202) is due to the noisy environment as illustrated in FIG. 2A. It can be seen in FIG. 2B that the total MSE can be minimized by choosing the value of μ corresponding to the intersection of the curves (204).
The last environment is a time varying, non-stationary system in a noisy environment. The total MSE in this case consists of the same components as in FIG. 2B. The difference between the two systems is that in this case, the curves are shifting or changing slope over time causing the minimum point on the curve to shift thus changing the optimal value of μ over time. This environment is illustrated by comparing FIGS. 2B and 2C. FIG. 2B represents the MSE characteristic at some time t 1 while FIG. 2C represents the MSE characteristic at some later time t 2 .
A fixed update coefficient in the last environment would not provide adequate filter performance due to the changing environment. There is a resulting need for automatically adapting the update coefficient according to the vehicle speed and channel conditions thereby improving filter performance.
SUMMARY OF THE INVENTION
The method of the present invention produces an optimum adaptive filter update coefficient in an apparatus having a plurality of adaptive algorithms, each adaptive algorithm having an update coefficient. The method starts by comparing performances of each of the plurality of adaptive algorithms then modifying the update coefficients in response to a difference in the performances.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of a typical adaptive filter.
FIGS. 2A, B, and C show graphs representing three different adaptive filter operating environments.
FIG. 3 shows a block diagram of the preferred embodiment of the process of the present invention.
FIG. 4 shows a block diagram of an alternate embodiment of the process of the present invention.
FIG. 5 shows a graph of MSE versus μ in accordance with the process of the present invention.
FIG. 6 shows a plot of a fixed update coefficient and an optimized update coefficient in accordance with the process of the present invention.
FIG. 7 shows a plot of an update coefficient, in accordance with the process of the present invention, in a delay spread environment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The process of the present invention provides automatic adjustment and optimization of an adaptive filter update coefficient in a changing environment. The update coefficient is continuously updated by a feedback signal that is generated by the filtered difference between MSE estimates for two adaptive filters.
A block diagram of the preferred embodiment of the process of the present invention is illustrated in FIG. 3. The process is comprised of three adaptive filters (301-303). Each of the filters is identical except for having different update coefficients, μ 1 , μ 2 , and μ 3 . The second update coefficient, μ 2 , is the coefficient that is optimized by the process. The optimal update coefficient is subsequently referred to as μ*. Since μ 2 is the optimized update coefficient, the second adaptive filter (302) is the filter used to perform the actual desired adaptive filtering function.
The update coefficients have the following relationship:
μ.sub.1 <μ.sub.2 <μ.sub.3
μ.sub.1 =μ.sub.2 -μ.sub.d
μ.sub.3 =μ.sub.2 +μ.sub.d,
where μ d is a constant chosen for the particular system in which the communication device is to operate as well as the particular adaptive algorithm used. In an alternate embodiment, μ d would vary with time as the update coefficients change. In the preferred embodiment, μ d is 0.01 using an LMS adaptive algorithm.
The process first generates error signals from the adaptive filters (301-303). This is accomplished by the adaptive filters (301-303) filtering the input signal in such a way that it forms a signal that matches the reference signal as close as possible. In the preferred embodiment, the input is the detected symbols in the communication receiver. These output signals are referred to as OUTPUT1, OUTPUT2, and OUTPUT3 in FIG. 3. Each output signal from the filters is then subtracted (304-306) from a reference signal. In the preferred embodiment, the reference signal is the received signal. The difference between these two signals is the error signal.
Mean square error estimates are performed (307 and 308) on the error signals from the first and third adaptive filters (301 and 303). The MSE for each error signal is estimated as follows: ##EQU1## where k is the start value and n is the number of samples of the error signal. For example, if k=1 and n=10 for the first estimation cycle, k will start at 12 for the next cycle.
The difference between the estimated MSE's (309), E d =E T1 -E T3 , provides an indication of which direction to move along the μ axis to get closer to μ*. In the preferred embodiment, E d is input to a comparator (310) where it is compared to 0. If E d <0, then μ 1 is closer to μ* than μ 3 . The coefficients, therefore, should be decremented in order to move μ 2 closer to μ*. In this case, the coefficient updates are illustrated as follows:
if E.sub.d <0 then:
μ.sub.1 =μ.sub.1 -Δ
μ.sub.2 =μ.sub.2 -Δ
μ.sub.3 =μ.sub.3 -Δ,
otherwise, if E d >0 then the coefficients should be incremented:
μ.sub.1 =μ.sub.1 +Δ
μ.sub.2 =μ.sub.2 +Δ
μ.sub.3 =μ.sub.3 +Δ,
where Δ is the update coefficient step size. This value is application dependent. Δ can be chosen as a very small value for time invariant and stationary environments and slightly larger for non-stationary environments. This value determines the resolution of the update coefficient estimate and the adaptation speed of the update coefficient. In the preferred embodiment, Δ is 0.005 using an LMS adaptive algorithm. As with μ d , in an alternate embodiment, Δ could vary with time.
In an alternate embodiment, illustrated in FIG. 4, E d is input to a filter (410) instead of a comparator. The filter provides a time varying step size (compared to the fixed step size Δ) that is responsive to the size of the error difference signal. For example, when the error difference signal becomes large, the step size automatically increases resulting in faster convergence of the algorithm. Using the filter, however, increases the complexity of the invention and may cause stability problems if a higher order filter is used. A first order digital infinite impulse response (IIR) filter is preferred due to stability and simplicity considerations. In this case, the update coefficients are adapted by adding the value of the output of the filter to the coefficients.
After several adaptation iterations, μ 1 is slightly smaller than μ*, μ 3 is slightly larger than μ*, μ 2 is approximately equal to μ*, and the error difference signal is approximately zero. Adaptive filter 2(302) is now optimized for the current environment. If the environment changes, the process of the present invention detects and tracks the change to maintain the optimality of adaptive filter 2(302).
The above described process can be illustrated graphically as seen in FIG. 5, a plot of MSE versus μ. In the case where E d <0, E T1 and E T3 (501) are on the right part of the curve and must move down the curve to the left in order to locate μ 2 at the bottom of the curve which is the optimum point. This requires decrementing the update coefficients by Δ to move μ 2 closer to the μ* point. Similarly, if E d >0, E T1 and E T3 (502) are on the left part of the curve and must move down the curve to the right to locate μ 2 at the optimum point. This requires incrementing update coefficients by Δ to move μ 2 closer to the μ* point (503).
The improvement using the process of the present invention over a fixed update coefficient is illustrated in FIGS. 6 and 7. In these graphs, the process is used with a least mean square (LMS) adaptive channel estimator in simulations of a Maximum Likelihood Sequence Estimation equalizer for the U.S. digital cellular system. The fixed update coefficient is set at μ=0.38 to allow adequate performance when the mobile radiotelephone is traveling in vehicle at high speeds. By using the process of the present invention, the performance of the equalizer is improved at significantly lower vehicle speeds, as illustrated in FIG. 6. FIG. 6 shows the performance of the equalizer as a function of multipath delay and the vehicle speed is approximately 5 mph. FIG. 7 shows how the process operates in a channel with delay spread and co-channel interference when the vehicle speed drops instantaneously from 63 mph to 5 mph. It can be seen that the update coefficient quickly decreases to a new lower level suitable for the lower vehicle speed.
In the preferred embodiment, the process of the present invention is implemented as an algorithm. Alternate embodiments of the invention can be implemented in hardware or combinations of hardware and software; each block of the process being either an algorithm or a hardware circuit equivalent of that block.
In summary, a process of automatically optimizing an adaptive filter update coefficient in a changing environment has been described. By comparing the performance of each adaptive algorithm to determine how to change the update coefficients, an optimal update coefficient for that particular environment can be obtained. Communication devices using the process of the present invention can out-perform devices using a fixed update coefficient.
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The method of the present invention generates an optimal adaptive filter update coefficient by first generating three error signals using a signal input and three update coefficients (301-303). Mean Square Error (MSE) values are estimated (307 and 308) for the first and third error signals. The first MSE value (307) is substracted (309) from the third MSE value (308) to generate a difference signal. The difference signal is used to generate (310) an update signal that is used to modify the update coefficients. The process of the present invention is repeated until the difference signal is substantially zero, thus optimizing the second update coefficient. This process enables an update coefficient for an adaptive filter to quickly adapt to a changing environment.
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FIELD OF THE INVENTION
[0001] The invention relates to an exhaust gas system for an internal combustion engine to be connected to a manifold. The exhaust gas system consists of at least one first section provided in the direction of flow directly or indirectly downstream of the manifold, and of a second section following it in the direction of flow with the two sections being interconnected via a mechanical de-coupling element.
BACKGROUND OF THE INVENTION
[0002] The exhaust gas system Is mechanically de-coupled by means of the de-coupling element for providing a certain degree of flexibility over the length of the vehicle. As mechanical de-coupling elements non-self-supporting, flexible connecting elements, such as corrugated tubes or flexible, tubes are, inserted between two sections of the exhaust gas system. Due to the fact that the corrugated tubes or flexible tubes are hot self-supporting, they must be supported. Owing to their small degree of stiffness and flexibility, they have also the inherent property of absorbing to a certain extent vibrations in certain frequency ranges. Such flexible sound-absorbing insulating elements are described for instance in U.S. Pat. No. 5,456,291 A and in EP 1 431 538 B1.
[0003] For a mechanical articulated de-coupling of two pipe flanges or casing flanges of an exhaust gas system which permits a relative bending of the exhaust gas system, also jolted connecting elements which have a joint-like flexibility are inserted between two sections. These de-coupling elements which are described in DE 198 12 611 C2 or in JP 199789173 A (Hei9-89173) are shaped as a jolted pipe length which forms in the longitudinal section an S-shaped spring. Owing to the reduced wave shape the said connecting elements are stiff when compared to the corrugated tubes; they are, however, self-supporting. In order to increase their flexibility they can be provided with a longitudinal slot according to DE 198 12 611 C2.
[0004] It is known that due to most different modern construction methods for exhaust gas systems and internal combustion engines, an increasing number of vibrations in the audible range are caused, in spite of a mechanical de-coupling, by resonance in different components. Flatter forms of mufflers, the use of thin-wall, ventilation-slot-insulated sheet metal manifolds and turbochargers in diesel engines as well as changes in the combustion process result in additional vibrations in the structures and thus in additional solid-borne vibrations.
[0005] This kind of solid-borne vibration may be reduced directly in the structures by means of sound-absorbing insulating elements in the exhaust gas system or also by great impedance leaps in components of an exhaust gas system.
[0006] According to DE 10 2006 040 980 A1 impedance leaps are achieved with a sound-absorbing insulating element provided with radial widenings of the cross-section which are attached onto the pipe like a pipe clamp.
[0007] In DE 20 2004 005 526 U1 a rigid flanged joint is described for the reduction of solid-born vibrations which muffles the transmission of vibrations by means of a line-shaped structure in the circumferential direction around the pipe axis or flange axis.
SUMMARY OF THE INVENTION
[0008] The object of the invention is to muffle resonance vibrations within the range above 600 Hz in an exhaust gas system by more than 15 dB and to provide at the same time ah exhaust gas system which is sufficiently rigid and self-supporting as well as permanently gas-proof.
[0009] The object is accomplished by the integration, in combination with a mechanical de-coupling elements of a single-wall and self-supporting sound-absorbing insulating element into the exhaust gas system in flow direction upstream of or within the first section, with the sound-absorbing insulating element being provided with at least an internal connecting sleeve and with at least one external connecting sleeve offset to the outside in a direction radial to a central axis, with a central section longitudinally jolted in the direction of the central axis being provided that is arranged between the two connecting sleeves and connects the two connecting sleeves, with the cross-section of the said central section forming a U or S eccentricity.
[0010] It was found out through sound measurements that the known flexible and self-supporting mechanical de-coupling elements in the form of a jolted pipe length with an S eccentricity in the frequency range above 600 Hz, in particular from 3,000 Hz to 6,000 Hz, have sound-absorbing insulating properties which were not to be expected that reduce to a considerable extent the interactions in the other sections of the exhaust gas system and the generation of solid-borne vibrations. The geometric and constructive measures taken with a view to achieving a greatest possible damping resulted in the finding that very good damping properties can be achieved even with a comparatively rigid and self-supporting configuration of the S shaped decoupling element.
[0011] In this context it is advantageous to configure the tube-shaped sound-absorbing insulating element in the direction of the central axis as short as possible thereby accomplishing a flexural rigidity adequate for its use as a self-supporting sound-absorbing insulating element. In the region where the sound-absorbing insulating element is integrated into the exhaust gas system it need not function as a mechanical de-coupling element and may have a relative flexural rigidity.
[0012] Here, it may also be of importance that the push-in depth is in the range from 5 mm to 16 mm, maximally 30 mm.
[0013] In accordance with the invention the insulating property can be further improved when the sound-absorbing insulating element is connected directly upstream of or to the component which in the last analysis generates the resonance in the transmitting components. The internal radius and the external radius have advantageously a size from 6 mm to 30 mm with both radii having, however, a different size in relation to each other.
[0014] In this connection it may also be advantageous when the internal connecting sleeve in the direction of the central axis is positioned offset to the external connecting sleeve and/or when the two connecting sleeves overlap each other by the size of a push-in depth e from 5 mm to 30 mm. The length of the push-in depth e is the measure by which the external connecting sleeve in the direction of the central axis projects beyond the internal connecting sleeve. For the said length, both the pipe length that is provided between the internal radius and the external radius and the two radii themselves are to be taken into account for the size of the push-in depth e. The shorter the push-in depth e, the greater the sound-absorbing insulation which is accomplished with the element.
[0015] Moreover, it is advantageous that the basic diameter of the internal connecting sleeve is smaller by at least 20% to maximally 40% than the diameter of the external connecting sleeve. The sound-absorbing insulation can be essentially influenced by the two end geometries of the two connecting sleeves since the vibration behaviour distinctly deviates in the event of transmission from a small to a larger connecting sleeve from the vibration behaviour which would be attained when the internal connecting sleeve as intake connecting sleeve would have the same size as the external connecting sleeve as exhaust connecting sleeve.
[0016] As far as the insulating properties are concerned, it may also be advantageous when a central section which connects the two tube-shaped connecting sleeves is provided with at least one external radius connected at the external connecting sleeve and one internal radius connected at the internal connecting sleeve as well as a pipe length connecting the two radii, with the pipe wall of the pipe length being arranged in parallel to or in an angle a between 2.5° and 15° to the central axis. This additional possibility of influencing the insulating effect offers also the advantage that in the presence of a connecting geometry for the internal connecting sleeve or for the external connecting sleeve the size of the two radii can be varied, i.e. that with very small radii this pipe length includes an increasingly larger angle a to the central axis. Another advantage is that the connecting geometry can be enlarged or reduced by the variation of angle a both for the internal connecting sleeve and for the external connecting sleeve.
[0017] In this connection it can also be advantageous when the single-wall sound-absorbing insulating element is made of sheet metal or cast metal and the insulating element is provided in a direction along the work piece with continuously or discontinuous increasing wall thicknesses ranging from 1 mm to 2.8 mm, in particular ranging from 1.2 mm to 1.9 mm. The insulating effect which is achieved by means of a decreasing Wall thickness has an advantageous effect in particular in the frequency range over and above 2,000 to 6,000 Hz. This is advantageous in particular insofar as when the diameter of the external connecting sleeve is adjusted from a smaller to a larger size the wall thickness does anyhow become thinner. Consequently, a cylindrical pipe with a basic diameter matching the internal connecting sleeve on the exhaust side would be adjusted up to the size of the diameter for the external connecting sleeve.
[0018] In addition it may be advantageous when the sound-absorbing insulating element has in the flow direction S downstream of the internal connecting sleeve a reduced internal diameter when compared to the basic diameter. By means of this measure, a kind of taper in the passage from the internal connecting sleeve to the central section is formed, by which in particular the vibrations which exist in the exhaust gas pipe are influenced in respect of the insulation.
[0019] It may be of particular importance for the present invention When the sound-absorbing insulating element is made of an adjusted pipe length with a basic diameter on the intake side from 45 mm to 85 mm and a diameter on the exhaust side from 55 mm to 115 mm as well as with an absolute length in the direction of the central axis from 230 mm to 420 mm. The ratio of basic diameter to diameter sub-stantially influences the insulating property of the element.
[0020] In connection with the inventive configuration and arrangement it may be advantageous when the sound-absorbing insulating element is integrated into an end wall of a sheet metal housing for a filter or a converter or a muffler with at least a part of the end wall connecting in a radial direction to the central axis to the internal connecting sleeve, and/or to the external connecting sleeve. This facilitates the integration of the insulating element, into a component that is present in the exhaust gas systems and to which an exhaust gas pipe would anyhow be connected. Moreover, the integration into an end wall offers the advantage that the overall length and thus also the rigidity of the element can be increased which has an essential impact on the insulating property.
[0021] Furthermore, it can be advantageous when the sound-absorbing insulating element, is positioned at an outlet of a housing for a turbocharger. Since turbo-chargers make, a comparatively great contribution to the solid-borne vibration which is generated in the exhaust gas system within the range from 600 Hz to 6 kHz, a positioning of such ah insulating element directly downstream of the turbocharger is of great importance, and by means of such a positioning the greater diameter adjusted in the area of the external connecting sleeve can be more easily integrated into the geometry of ah exhaust gas system because this external connecting sleeve is connected directly to the housing, and a possibly required reduction of the diameter again down to the size of the diameter that is provided for the other exhaust gas pipes which corresponds to the internal connecting sleeve is not necessary.
[0022] Furthermore, the use of a mechanical de-coupling element for an exhaust gas system for the sound-absorbing insulation of an exhaust gas system within the frequency range from 600 Hz to 6 kHz can be advantageous when the sound-absorbing insulating element is provided with at least one internal connecting sleeve and at least one external connecting sleeve offset to the outside in a direction radial to a central axis, with a jolted central section being provided that is arranged between the two connecting, sleeves and connects the two connecting sleeves, with the cross-section of the said central section forming a U or S eccentricity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Further advantages and details of the invention are explained in the patent claims and in the description and are shown in the figures in which
[0024] FIG. 1 shows an exhaust gas system connected to ah engine;
[0025] FIG. 2 shows a cross-section of an insulating element which is integrated between two components of an exhaust gas system;
[0026] FIG. 3 shows an upper section of a cross-section of an insulating element with an internal diameter that is reduced when compared to the basic diameter;
[0027] FIG. 4 shows a cross-section of an insulating element with a pipe section positioned opposite the central axis;
[0028] FIG. 5 shows the integration of an insulating element into an end wall of a housing;
[0029] FIG. 6 shows, a configuration according to FIG. 5 where the insulating element is positioned in a radial direction centrally to the end wall;
[0030] FIG. 7 shows a configuration according to FIG. 6 where the insulating element has a U eccentricity;
[0031] FIG. 8 shows the integration of an insulating element into a cone-shaped end wall of a sheet metal housing.
DETAILED DESCRIPTION OF THE INVENTION
[0032] FIG. 1 shows an exhaust gas system 4 consisting of a first section 41 and a second section 42 . The first section 41 is formed by a converter 45 and exhaust gas pipes 47 connected on both sides of converter 45 . The second section 42 consists of a particulate filter 44 and a muffler 46 , with the particulate filter 44 and the muffler 46 being interconnected via an exhaust gas pipe 47 . Upstream of the particulate filter 44 there is also provided an exhaust gas pipe 47 to which a mechanical de-coupling element 40 is connected which interconnects the two sections 41 , 42 . The purpose of the mechanical de-coupling element 40 is essentially to guarantee a certain freedom of movement of the exhaust gas system 4 over its entire length.
[0033] The entire exhaust gas system 4 is connected via a sound-absorbing insulating element 1 to an outlet opening of a turbocharger 5 which connects the exhaust gas system 4 via the manifolds 3 with the internal combustion engine 2 . The vibrations which are supplied into the exhaust gas system 4 via the exhaust gas flow and the turbocharger 5 are substantially damped via the sound-absorbing insulating element 1 within the range from 600 Hz to 6 kHz so that the solid-borne emissions of converter 45 , of particulate filter 44 and of muffler 46 are reduced. At the same time, the vibrations that are still present in the first section 41 of the exhaust gas, system 4 are also influenced and also partially damped by the mechanical de-coupling element 40 so that the combination of the sound-absorbing insulation with the insulating element 1 and the damping of vibration with the mechanical de-coupling element 40 brings about a reduction of the solid-borne vibration within the second section 42 of exhaust gas system 4 .
[0034] FIG. 2 shows a schematic cross-section of a sound-absorbing insulating element 1 with an S eccentricity 120 . The sound-absorbing insulating element 1 is provided with an internal connecting sleeve 10 and an external connecting sleeve 15 in a radial direction to the central axis 13 . The external connecting sleeve 15 projects in the axial direction to the central axis 13 beyond the internal connecting sleeve 10 , The connection of the external connecting sleeve 15 with the internal connecting sleeve 10 forms a central section 12 with an S eccentricity 120 in the cross-section. The central section 12 is formed by the external radius 152 connected to the external connecting sleeve 15 and the internal radius 102 connected to the internal connecting sleeve, 10 as well as by a pipe length 14 which connects the two radii 102 , 152 .
[0035] The projection of the external connecting sleeve 15 beyond the internal connecting sleeve 10 is termed push-in depth e the total of which is made up by the size of the pipe length 14 and the two radii 102 , 152 . The length L of the insulating element 1 in the direction of the central axis 13 is measured from the intake opening at the internal connecting sleeve 10 up to the exhaust opening at the external connecting sleeve 15 .
[0036] As is shown in FIG. 2 , an exhaust gas pipe 47 connects to the internal connecting sleeve 10 in the flow direction S upstream of the insulating element 1 . In the flow direction S downstream of the insulating element 1 a schematically shown exhaust gas element 48 is connected to the insulating element 1 . In FIGS. 5 to 8 , examples of such exhaust gas elements 48 are shown by sheet metal housings 43 .
[0037] The S eccentricity 120 can have, in different embodiments which are not shown, a basic diameter 101 at the intake side ranging from 45 mm to 85 mm and a diameter 151 at the exhaust side ranging from 55 mm to 115 mm as well as an absolute length L in the direction of the central axis 13 ranging from 230 mm to 420 mm, where the ratio of the diameters 101 , 151 and of the length L can be selected in such a manner that the natural frequency at a medium input frequency
a) of 350 Hz amounts to a medium axial transmission loss of at least −18 dB and b) of 600 Hz amounts to a medium axial transmission loss of at least 0 dB and c) of 1,000 Hz amounts to a medium, axial transmission loss of at least 8 dB and d) of 3*000 Hz amounts to a medium axial transmission loss of at least 20 dB.
[0042] With these parameters of the geometry the natural frequency can be shifted when compared to a cylindrical exhaust gas pipe within the range from 400 Hz to 700 Hz, with a positive damping being achievable as from 600, Hz or as from 900 Hz. Moreover, a maximum damping of 30 dB can be achieved in the range from 600 Hz to 6 kHz.
[0043] FIG. 3 shows a special embodiment of the S eccentricity 120 where the pipe length 14 which is provided between the two radii 102 , 152 is positioned opposite the central axis 13 by an angle a. It can be seen that the pipe length 14 is thus not positioned in parallel to the central axis 13 as is shown for instance in FIG. 3 . Through the variation of the angle a both the basic diameter 101 of the internal connecting sleeve 10 and the diameter 151 of the external connecting sleeve 15 can be varied in relation to each other. In particular in the event, when the sound-absorbing insulating element 1 is made from a cylindrical pipe and adjusted which has essentially a pipe diameter that Corresponds to the basic diameter 101 of the internal connecting sleeve 10 , the external connecting sleeve 15 is adjusted by a specific size. In accordance with the required geometrical sizes and with a view to the wall thickness which is essential for the external connecting sleeve 15 , the diameter 151 of the external connecting sleeve 15 can be varied by means of the variation of angle a, in particular when the internal and the external radius 102 , 152 are to have, a fixed size. Also in this embodiment the push-in depth e is decisive through the size of the two radii 102 , 152 and the length L of the pipe length a in the direction of the central axis 13 .
[0044] When compared to FIG. 3 , FIG. 4 shows a modified embodiment in which Within the area of the internal radius 102 the internal diameter 103 is reduced when compared to the basic diameter 101 of the internal connecting sleeve 10 . In flow direction S a compression of the exhaust gas flow is thus achieved, and, at the same time, influence is exerted on the acoustic waves inside the internal connecting sleeve 10 .
[0045] FIG. 5 shows a preferred embodiment where the sound-absorbing insulating element 1 is integrated into an end wall 430 of a sheet metal housing 43 of an exhaust gas system 4 . In particular in spun mufflers the end wall 430 is inserted in the direction of the central axis 13 into the sheet metal housing 43 so that the mounting of the insulating element 1 into the end wall 430 is possible prior to the winding of the housing. For this purpose, the sound-absorbing insulating element 1 with the external connecting sleeve 15 is welded into a corresponding opening of the end wall 430 . The diameter 151 of the external connecting sleeve 15 which is considerably larger than that of the internal connecting sleeve 10 practically forms the exhaust side for the exhaust gas that is flowing in the flow direction S so that the exhaust gas and/or the exhaust gas flow further propagate downstream of the sound-absorbing insulating element 1 in the sheet metal housing 43 in radial direction. This offers also the advantage that by means of a reduction of the diameter 151 of the external connecting sleeve 15 in the event of a continuation within the exhaust gas pipe which has approximately the same diameter as the internal connecting sleeve 10 , a decrease of the cross-sectional area can be avoided.
[0046] FIG. 6 shows an embodiment similar to that in FIG. 5 as far as the positioning within ah end wall 430 of a sheet metal housing 43 is concerned. In this ease, the S shaped sound-absorbing insulating element 1 is, however, positioned in a radial direction to the central axis 13 approximately in the centre of the end wall 430 so that, starting from the exhaust gas pipe 47 that is mounted in the end wall 430 , at first a first section of the end wall 430 in the radial direction forms a connection to the sound-absorbing insulating element 1 and, following the sound-absorbing insulating element 1 in the radial direction, a second section of the end wall 430 forms the joint and the connection to the circumferentially arranged sheet metal housing 43 . In this embodiment the internal connecting Sleeve 10 and the external connecting sleeve 15 are extremely short and the adjoining components are hot arranged, as in the preceding embodiments, in an axial direction to the central axis 13 adjoining the sound-absorbing insulating element 1 but in radial direction.
[0047] FIG. 7 shows an embodiment similar to that in FIG. 6 where the sound-absorbing insulating element 1 does not have an S shaped cross-section but a U shaped cross-section 120 . The U shaped sound-absorbing insulating element 1 is provided with one radius only that is termed internal radius 102 and can, due to the existing geometry, be used exclusively in those regions where the other components follow the, sound-absorbing insulating element 1 in the radial direction to the central axis 13 .
[0048] FIG. 8 shows an embodiment where the sound-absorbing insulating element 1 forms a connection between an exhaust gas pipe 47 and a sheet metal housing 43 with the sheet metal housing 43 having a cone-shaped end wall. Here, too, the larger diameter 151 of the external connecting sleeve 15 when compared to the diameter of the internal connecting sleeve 10 is advantageously accomplished through the connection to the sheet metal housing 43 so that a decrease of the cross-sectional area, of the diameter 152 of the external connecting sleeve 15 to a smaller size is not required.
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An exhaust system composed of a plurality of components for an internal combustion engine for connecting to a manifold, the exhaust system includes at least one, first section, which is provided indirectly or directly after the manifold in the flow direction, arid a second section, which is directly adjacent thereto in the flow direction, wherein the two sections are connected to each other by a mechanical decoupling element. The resonant oscillations in the range above 600 Hz are to be attenuated in the exhaust system by more than 15 dB and, at the same time, the exhaust system is to be sufficiently rigid and self-supporting and designed to be lastingly gas-tight. For this purpose, a single-walled arid self-supporting acoustic insulating element is integrated in the exhaust system in the flow direction upstream of, or in, the first section.
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CROSS-REFERENCE TO PRIOR APPLICATIONS
[0001] This is a Non Provisional U.S. Application of three provisional applications, claiming the benefit of U.S. Provisional Application No. 60/984,898, filed Nov. 2, 2007; U.S. Provisional Application No. 61/020,108 filed on Jan. 9, 2008; and US Provisional Application No. 61/083,566 filed on Jul. 25, 2008.
FIELD OF THE INVENTION
[0002] The present invention relates generally to methods of treating vitamin B 12 deficiency and pharmaceutical compositions for such treatment.
BACKGROUND OF THE INVENTION
[0003] Vitamin B 12 is important for the normal functioning of the brain and nervous system and for the formation of blood. It is involved in the metabolism of every cell of the body, especially affecting the DNA synthesis and regulation but also fatty acid synthesis and energy production. Its effects are still not completely known.
[0004] Cyanocobalamin is the most stable and widely used form of vitamin B 12 . It is bound to plasma proteins and stored in the liver. Vitamin B 12 is excreted in the bile and undergoes some enterohepatic recycling. Absorbed vitamin B 12 is transported via specific B 12 binding proteins, transcobalamin I and II, to the various tissues. The liver is the main organ for vitamin B 12 storage.
[0005] Vitamin B 12 deficiency can potentially cause severe and irreversible damage, especially to the brain and nervous system. Oral tablets containing vitamin B 12 have been developed to treat vitamin B 12 deficiency. However, many patients with vitamin B 12 deficiency do not respond to oral vitamin B 12 treatment. There is a need to develop a treatment for these patients.
BRIEF SUMMARY OF THE INVENTION
[0006] One aspect of the invention is directed to a method for treating vitamin B 12 deficiency in a subject, comprising the steps of (a) preparing a pharmaceutical composition for oral administration containing (1) vitamin B 12 and (2) at least one substance selected from the group consisting of N-[8-(2-hydroxybenzoyl)amino]caprylic acid and its pharmaceutically acceptable salts; and (b) administering the pharmaceutical composition to the subject to effectively treat said vitamin B 12 deficiency.
[0007] Another aspect of the invention is directed to a pharmaceutical composition for treating vitamin B 12 deficiency in a subject, comprising (1) vitamin B 12 and (2) at least one substance selected from the group consisting of N-[8-(2-hydroxybenzoyl)amino]caprylic acid and its pharmaceutically acceptable salts; wherein said subject had failed to respond to existing oral vitamin B 12 treatment.
[0008] The contents of the patents and publications cited herein and the contents of these documents cited in these patents and publications are hereby incorporated herein by reference to the extent permitted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a graph of serum vitamin B 12 concentration as a function of time.
DETAILED DESCRIPTION
[0010] As used herein, the term “SNAC” means Sodium-N-salicyloyl-8-aminocaprylate, Monosodium 8-(N-salicyloylamino) octanoate, N-(salicyloyl)-8-aminooctanoic acid monosodium salt, monosodium N-{8-(2phenoxybenzoyl)amino}octanoate, E414 monosodium salt or sodium 8-[(2-hydroxybenzoyl)amino]octanoate. It has the structure
[0000]
[0000] “N-[8-(2-hydroxybenzoyl) amino]caprylic acid” has an empirical formula C 15 H 21 NO 4
[0011] The term “Vitamin B 12 ” means any member of a group of cobalt-containing compounds known as cobalamins which include, but is not limited to cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5-deoxyadenosylcobalamin.
[0012] The term “treatment” or “treating” means any treatment of a disease or disorder in a mammal, including: preventing or protecting against the disease or disorder, that is, causing the clinical symptoms not to develop; inhibiting the disease or disorder, that is, arresting or suppressing the development of clinical symptoms; and/or relieving the disease or disorder, that is, causing the regression of clinical symptoms. The term “mammal” include human subjects.
[0013] The terms “carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent, solubilizing agent” are as defined in the Handbook of Pharmaceutical Excipients (fourth edition) by Raymond C. Rowe, Paul J. Sheskey and Paul J. Weller, the content of which is herein incorporated by reference.
[0014] The term “intrinsic factor protein” means is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B 12 later on in the terminal ileum.
[0015] In a preferred embodiment, the treatment is directed to subjects that had failed to respond to existing oral vitamin B 12 treatment. Preferably, tablets are used for the treatment. Such tablets contain from about 0.01 mg to about 25 mg of vitamin B 12 and from about 1 mg to about 600 mg of SNAC each, preferably from about 0.02 mg to about 25 mg of vitamin B 12 and more preferably from about 0.1 mg to about 20 mg of vitamin B 12 and the most preferably from about 0.5 mg to 10 mg of vitamin B 12 and from about 10 mg to about 200 mg of SNAC in each tablet.
[0016] The preferred weight ratio of vitamin B 12 and SNAC in the tablet is from about 2:1 to about 1:700, more preferably from about 1:2 to about 1:600 or from about 1:3 to about 1:20 and the most preferably from about 1:4 to about 1:10.
[0017] In a preferred embodiment, the pharmaceutical composition is in the form of tablets. Preferrably, each tablet contains from about 0.01 mg to about 25 mg of vitamin B 12 and from about 50 mg to about 600 mg of SNAC. More preferably, each tablet contains from about 0.02 mg to about 20 mg of vitamin B 12 . More preferably, each tablet contains from about 0.1 mg to about 10 mg of vitamin B 12 . The most preferably, each tablet contains about 15 to 20 mg of vitamin B 12 and about 50 to 100 mg of SNAC, or about 0.1 to 1.5 mg of vitamin B 12 and about 25 to 150 mg of SNAC.
[0018] In another preferred embodiment, the tablet further contains at least one of a carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent, solubilizing agent or combinations thereof.
[0019] In another preferred embodiment, the tablet optionally contains from about 1 to 25 mg of Capmul PG-8 and optionally contains from about 0.5 to 10 mg of providone. Preferably, Capmul PG-8 is in an amount from about 2 to 20 mg and Providone is in an amount from about 1 to 8 mg. Preferably, Capmul PG-8 is in an amount from about 5 to 15 mg and the Providone is in an amount from about 1.5 to 5 mg. More preferably, Capmul PG-8 is in an amount from about 5 to 10 mg and Providone is in an amount from about 1.5 to 5 mg.
[0020] Without intending to be bound by any particular theory of operation, it is believed that gastrointestinal absorption of vitamin B 12 depends on the presence of sufficient intrinsic factor protein, secreted from gastric parietal cells. The average diet supplies about 10 mcg/day of vitamin B 12 in a protein-bound form that is available for absorption after normal digestion. Vitamin B 12 is bound to intrinsic factor during transit through the stomach; separation occurs in the terminal ileum, and vitamin B 12 enters the mucosal cell for absorption via a receptor mediated process. It is then transported by the transcobalamin binding proteins. A small amount (approximately 1% of the total amount ingested) is absorbed by simple diffusion, but this mechanism is adequate only with very large doses. It is also believed that SNAC will allow B 12 to bypass its usual receptor mediated process.
[0021] The following examples are given as specific illustrations of the invention. It should be understood, however, that the invention is not limited to the specific details set forth in the examples. All parts and percentages in the examples, as well as in the remainder of the specification, are by weight unless otherwise specified.
[0022] Further, any range of numbers recited in the specification or paragraphs hereinafter describing or claiming various aspects of the invention, such as that representing a particular set of properties, units of measure, conditions, physical states or percentages, is intended to literally incorporate expressly herein by reference or otherwise, any number falling within such range, including any subset of numbers or ranges subsumed within any range so recited. The term “about” when used as a modifier for, or in conjunction with, a variable, is intended to convey that the numbers and ranges disclosed herein are flexible and that practice of the present invention by those skilled in the art using concentrations, amounts, contents, carbon numbers, and properties that are outside of the range or different from a single value, will achieve the desired result, namely, effective treatment of a subject with vitamin B 12 deficiency which failed to respond to existing oral vitamin B 12 tablets as well as pharmaceutical compositions for such treatment.
EXAMPLE 1
[0023] Preparation of N-[8-(2-hydroxybenzoyl)amino]caprylic Acid and SNAC
[0024] The preparation method for N-[8-(2-hydroxybenzoyl) amino]caprylic acid and SNAC involves the following steps: The starting material is salicylamide, which is converted to form Carsalam. The second step involves the alkylation of Carsalam. The penultimate step is a hydrolysis to cleave the ethyl protection group at the end of the alkyl chain and spring open the heterocyclic ring forming the free acid of SNAC. In the final step, the sodium salt of the SNAC free acid is formed by reaction with a 1% excess stoichiometric amount of sodium hydroxide base. Upon cooling the precipitated product is isolated by centrifugation and vacuum dried prior to packaging. The in-process controls for the synthetic scheme are given in Table I.
[0000]
TABLE I
In-process controls for SNAC Manufacturing Process.
Desired
In-Process
Step
Reaction
Product
Specification
Control
1
Carsalam
Carsalam
<10% salicylamide
HPLC
2
Alkylation
Alkylated
<8% Carsalam
HPLC
Carsalam
3
Hydrolysis
SNAC Free
<0.5%
LOD
acid
4
Sodium Salt
SNAC Sodium
95-105%
HPLC
salt
EXAMPLE 2
Preparation of Vitamin B 12 Tablets.
[0025] The tablet die and punches are checked to ensure that they are clean and that their surfaces are dusted with magnesium stearate powder. Vitamin B 12 , SNAC, carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent, solubilizing agent are screened through a #35 sieve and transferred into a sealed containers. 50 mg of Vitamin B 12 is weighed and mixed thoroughly with 11 grams of a carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent and/or solubilizing agent. 100 vitamin B 12 tablets are made, with each tablet containing 0.5 mg of Vitamin B 12 and 110 mg of a carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent and/or solubilizing agent. These tablets are used as a control.
EXAMPLE 3
Preparation of Vitamin B 12 and SNAC Tablets
[0026] 50 mg of Vitamin B 12 , 1 gram of SNAC are weighed and thoroughly mixed with 10 grams of a carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent and/or solubilizing agent. 100 vitamin B 12 tablets are made, with each tablet containing 0.5 mg of Vitamin B 12 . 10 mg of SNAC and 100 mg of a carrier, excipient, emulsifier, stabilizer, sweetener, flavoring agent, diluent, coloring agent and/or solubilizing agent. The process is repeated to make tablet batches containing 1.0 mg, 0.8 mg, 0.6 mg, 0.4 mg and 0.2 of Vitamin B 12 , respectively. These tablets have the following specifications for release of SNAC component:
[0000]
Analytical
Tests
Specification
Method
Appearance
White to light-tan powder with
AM001
pink hue
Identification
Test for Sodium
Confirms presence of Sodium
USP <191>
FTIR
Conforms to reference standard
USP <197K>
Melting Range/
193-203° C. with a range not to
USP <741>
Temperature
exceed 5° C.
Water Content
NMT 3.0%
USP <921>
Method I
Heavy Metals
<20 ppm
USP <231>
Method II
Sodium Content
6.9 to 8.4%
AM017
Residual Solvents
Ethanol
Less than 4000 ppm
AM008
Heptane
Less than 500 ppm
AM008
Assay as SNAC
90.0-110.0% w/w
AM016
Sodium salt
(As Is)
Example 4
Preparation of Tablets for Testing on Rats
[0027] Tablets with four types of different ingredients were made as follows: (1) 8.8 mg of vitamin B 12 , 35 mg of SNAC were weighed, thoroughly mixed and made into a tablet for dosing on rat; (2) 8.8 mg of vitamin B 12 , 35 mg of SNAC and 5 mg of Capmul PG-8 were weighed, thoroughly mixed and made into a tablet; (3) 8.8 mg of vitamin B 12 , 35 mg of SNAC and 0.9 mg of Providone were weighed, thoroughly mixed and made into a tablet. Each of the four processes was repeated to produce more tablets.
EXAMPLE 5
Dosing Sprague-Dawley Rats
[0028] Male Sprague-Dawley rats (325-350g) were dosed with vitamin B 12 intravenously (0.5 mg/kg) alone, or orally with the tablets made in Example 4 at a dose of 50 mg/kg vitamin B 12 alone or in combination with SNAC at 200 mg/kg. Blood samples were collected at 0, 3, 10, 20, 30, 60, 120, 240 and 360 minutes post dosing. Plasma samples were analyzed for B12 by RIA. The model independent PK metrics obtained following B12-SNAC combination were compared to those obtained following B12 alone. The testing results are shown in Table 1.
[0000]
TABLE 1
Comparative Testing Results for Vitamin B 12 Absorption
Cmax
Tmax
AUC
Mean
(ug/mL)
(min)
(ug * min/mL)
Bio-
Group (N = 5)
Mean
S.D
Mean
S.D
Mean
S.D
availability %
0.5 mg/kg Vitamin B 12
2.15
0.64
4.4
3.13
65.84
11
(IV)
50 mg/kg Vitamin B 12
0.14
0.07
52
17.9
28.72
13
0.42
alone (PO)
50 mg/kg Vitamin B 12 +
7.99
2.41
24
5.48
522.37
179
7.93
200 mg/kg SNAC (PO)
EXAMPLE 6
Preparation of Tablets for Testing on Human Subjects
[0029] Tablets were made from Cyanocobalamin, SNAC, Kollidon 90F, Anhydrous Emcompress USP/EP and Magnesium Stearate, NF/BP/EP/JP. Each tablet contains the followings:
[0000]
Ingredients
mg/tablet
Cyanocobalamin, USP (Intragranular)
5.00
SNAC (Intragranular)
100.00
Kollidon 90F, NF/EP/JP
2.00
(Providone K90; Intragranular)
Anhydrous Emcompress USP/EP (Diabasic
70.00
Calcium Phosphate, Anhydrous; Intragranular)
Anhydrous Emcompress USP/EP (Diabasic
21.00
Calcium Phosphate, Anhydrous; Extragranular)
Magnesium Stearate, NF/BP/EP/JP
2.00
(extragranular)
Total Weight
200.0
EXAMPLE 7
Dosing Human Subjects
[0030] Sixteen healthy male subjects were randomized to receive one of the following treatments:
[0031] (1) Treatment B: a single oral dose of cyanocobalamin/SNAC (5 mg cyanocobalamin/100 mg SNAC) administered in the fasted state as a tablet. (6 subjects);
[0032] (2) Treatment C: a single oral dose of cyanocobalamin alone (5 mg cyanocobalamin, VitaLabs, commercial) administered in the fasted state as a tablet. (6 subjects).
[0033] (3) Treatment D: a single intravenous dose of cyanocobalamin (1 mg cyanocobalamin) administered in the fasted state. (4 subjects). Each subject received a 1 mL intravenous injection of a 1 mg/mL (1000 μg/mL) solution resulting in a total dose of 1 mg cyanocobalamin.
[0034] The subjects were fasted overnight prior to dosing and had no liquids (including water) consumption for at least one hour before and after dosing. The oral forms of cyanocobalamin/SNAC tablets were administered in a single dose as tablets with 50 mL of plain water. Twenty-five blood samples were drawn for cyanocobalamin analyses at the following time points: within 30 minutes pre-dose and at Minutes 2, 5, 10, 20, 30, 40, 50, and at Hours 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 20 and 24 post-dose.
[0035] Pharmacokinetic metrics was obtained following a model independent pharmacokinetic analysis of individual cyanocobalamin concentrations. Descriptive statistics was used to summarize the results.
[0036] Following 1 tablet of 5 mg B12/100 mg SNAC mean B12 peak concentration is 12847±6613 μg/mL and occur within 1 hour post dose (mean tmax of 0.50±0.21 hours). Mean AUClast (0-24) value is 54618±16392 hr*pg/mL. The percent coefficient of variation (% CV) is 51.5% for Cmax and 30.0% for AUC.
[0037] Following a single oral dose of cyanocobalamin alone (5 mg cyanocobalamin, VitaLabs, commercial) mean B12 peak concentration is 1239±450 μg/mL and occur between 3 to 10 hours post-dose (mean tmax of 6.8±3.2 hours). Mean AUClast (0-24) value is 23131±8343 hr*pg/mL. The percent coefficient of variation (% CV) is 36.3% for Cmax and 36.1% for AUC.
[0038] Following a single intravenous dose of cyanocobalamin (1 mg cyanocobalamin) administered in the fasted state (4 subjects). Mean B12 peak concentration is 221287±80248 pg/mL and mean AUClast (0-24) value is 215391±44602 hr*pg/mL. The percent coefficient of variation (% CV) is 36.3% for Cmax and 20.7% for AUC.
[0039] The mean bioavailability of 1 tablet of 5 mg vitamin B12 alone, 1 tablet of 5 mg vitamin B12/100 mg SNAC, and 2 tablets of 5 mg vitamin B12/100 mg SNAC are 2.15±0.77%, 5.07±1.52, and 5.92±3.05%, respectively. (Note: 2 tablets of 5 mg vitamin B12/100 mg SNAC were dosed previously in a pilot arm are designated Treatment A).
[0040] The mean tmax of 1 tablet of 5 mg vitamin B12 alone, 1 tablet of 5 mg vitamin B12/100 mg SNAC, and 2 tablets of 5 mg vitamin B12/100 mg SNAC are 6.8±3.2 hours, 0.50±0.21 hours, and 0.54±0.32 hours, respectively.
[0041] No adverse events were observed during the given treatments. All formulations appear to be safe and well tolerated.
[0042] It was found surprisingly that the extent of B12 absorption, measured as Cmax and AUC, was significantly enhanced by the administration of the cyanocobalamin/SNAC combination. Vitamin B12 bioavailability was —240% greater for the 1 tablet of 5 mg B12/100 mg SNAC compared to 5 mg B12 commercial formulation. Mean peak B12 concentrations following B12 commercial oral formulation occurred significantly later compared to that following the B12/SNAC combinations likely due to a different site of absorption between the two oral formulations. This is consistent with literature data describing intestinal absorption of B12 occurring in the distal section of the gastrointestinal tract in the absence of the carrier.
[0043] The principles, preferred embodiments, and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protected herein, however, is not to be construed as limited to the particular forms disclosed, since these are to be regarded as illustrative rather than restrictive. Variations and changes may be made by those skilled in the art, without departing from the spirit of the invention.
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A novel method and composition for treating vitamin B 12 deficiency mammals that fail to respond to oral vitamin B 12 therapy.
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TECHNICAL FIELD
The present invention relates to an apparatus for inflating a vehicle occupant protection device and particularly relates to an electrically actuatable pyrotechnic igniter for an air bag inflator.
BACKGROUND OF THE INVENTION
An inflatable vehicle occupant protection device, such as an air bag, is inflated in the event of sudden vehicle deceleration such as occurs in a vehicle collision. The air bag restrains movement of a vehicle occupant during a vehicle collision. The air bag is inflated by inflation fluid from an inflator. The inflation fluid may be stored gas which is released from the inflator and/or gas generated by ignition of combustible gas generating material in the inflator. The inflator uses an electrically actuatable pyrotechnic igniter to open the container and release the stored gas and/or to ignite the gas generating material.
The electrically actuatable pyrotechnic igniter contains a charge of ignition material. The pyrotechnic igniter also contains a bridgewire that is supported in a heat transferring relationship with the ignition material. When the pyrotechnic igniter is actuated, an actuating level of electric current is directed through the bridgewire in the igniter. This causes the bridgewire to become resistively heated sufficiently to ignite the ignition material. The ignition material then produces combustion products that open the container and release the stored gas and/or ignite the gas generating material.
Radio frequency interference (RFI) suppression filters are commonly incorporated in an electrically actuatable pyrotechnic igniter. RFI suppression filters ensure that unwanted radio frequency (RF) signals are suppressed and allow the passage of direct current and low frequency alternating current. Failure to suppress RF signals might lead to the undesired actuation of the igniter.
In many cases, electrically actuatable pyrotechnic devices incorporating these RFI filters are also required to provide a gas-tight seal to protect sensitive components or materials contained within an enclosure. Many electrically actuatable pyrotechnic igniters incorporate a hermetically sealed chamber for their ignitable material that is vulnerable to degradation by the intrusion of water vapor.
SUMMARY OF THE INVENTION
The present invention is a pyrotechnic device. The pyrotechnic device comprises a body of ignitable material. A pair of electrodes provide electrical energy to heat and ignite the body of pyrotechnic material. The electrodes extend through an electrical insulation housing. The electrical insulation housing has surfaces defining a chamber through which the electrodes pass. A body of a solid electromagnetically lossy, substantially gas impermeable material is positioned within the chamber. The lossy material comprises a vitreous ceramic matrix consisting essentially of about 5% to about 50% by weight of a multi-component glass binder and about 50% to about 95% by weight of an electromagnetically lossy ferromagnetic and/or ferroelectric filler. The body of lossy material is fused to the surfaces defining the chamber in the electrical insulation housing and to the electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features of the invention will become more apparent to one skilled in the art upon consideration of the following description of the invention and the accompanying drawings in which:
FIG. 1 is a schematic view of a vehicle occupant protection apparatus embodying the present invention; and
FIG. 2 is an enlarged sectional view of a part of the apparatus of FIG. 1 .
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIG. 1, an apparatus 10 embodying the present invention includes an inflator 14 and an inflatable vehicle occupant protection device 26 . The inflator 14 contains a gas generating material 16 . The gas generating material 16 is ignited by an igniter 24 operatively associated with the gas generating material 16 . Electric leads 20 and 22 convey electric current to and from the igniter 24 . An electric current is conveyed to the igniter 24 through a crash sensor 18 from a power source (not shown). The crash sensor 18 acts as a switch in response to vehicle deceleration indicative of a vehicle collision. The current to the igniter 24 causes ignition of the gas generating material 16 . A gas flow means 28 , such as an opening in the inflator 14 , conveys gas, which is generated by combustion of the gas generating material 16 , to the vehicle occupant protection device 26 .
A preferred vehicle occupant protection device 26 is an air bag, which is inflatable to help protect a vehicle occupant in the event of a vehicle collision. Other vehicle occupant protection devices which can be used with the present invention are inflatable seat belts, inflatable knee bolsters, inflatable air bags to operate knee bolsters, inflatable head liners, inflatable side curtains, and seat belt pretensioners.
Referring to FIG. 2, the igniter 24 includes a header 30 . The header 30 is a generally cylindrical metal member preferably machined from 304L steel. The header 30 has a cylindrical outer surface 32 and flat, parallel, radially extending, circular opposite sides 34 and 36 . A cylindrical opening 40 extends completely through the header 30 parallel to a central axis 42 of the igniter 24 and intersects the opposite sides 34 and 36 of the header 30 .
A first electrode 44 is connected with the header 30 . The first electrode 44 is made from a conductive wire material, such as drawn nickel iron alloy wire, and extends parallel to the central axis 42 of the igniter 24 . The first electrode 44 has an inner end 48 , which is brazed to the side 34 of the header 30 , and an outer end 50 , which extends away from the header 30 and protrudes, in the form of a prong 46 , at one end of the igniter 24 .
A second electrode 52 extends parallel to the first electrode 44 . The second electrode 52 is made from the same material as the first electrode 44 . The second electrode 52 has an inner end 56 which extends axially through the cylindrical opening 40 in the header 30 . An outer end 58 of the second electrode 52 extends away from the opening 40 and forms a prong 54 , similar to the prong 46 of the first electrode 44 , at the one end of the igniter 24 .
A bridgewire 62 extends between the inner end 56 of the second electrode 52 and the side 36 of the header 30 . The bridgewire 62 is formed from a high resistance metal alloy. A preferred metal alloy is a nickel-chromium-iron alloy. Other suitable alloys for forming a high resistance bridgewire include platinum-tungsten and 304L steel. The bridgewire 62 heats up and generates thermal energy when an electrical current of predetermined magnitude passes through the bridgewire 62 .
The bridgewire 62 extends through a portion of a pyrotechnic charge 66 . The pyrotechnic charge 66 is a pyrotechnic material, which auto-ignites upon application of sufficient thermal energy. The pyrotechnic material can be any pyrotechnic material typically used in an igniter such as boron potassium nitrate (BKNO 3 ), potassium dinitrobenzofuroxan (KDNBF), barium styphnate monohydrate (BARSTY), cis-bis-(5-nitrotetrazolato)pentaaminecobalt(III)perchlorate (CP), diazidodinitrophenol (DDNP), 1,1-diamino-3,3,5,5-tetrazidocyclotriphosphazine (DATA), cyclotetramethylenetetranitramine (HMX), lead azide, and lead styphnate.
The pyrotechnic charge 66 is enclosed in an ignition cup 68 . The ignition cup 68 is a cup-shaped metal member preferably made from drawn 304L stainless steel. The ignition cup 68 has a cylindrical wall 74 , which defines a cavity 76 in which the pyrotechnic charge 66 is disposed. A portion 70 of the wall 74 of the ignition cup 68 overlies most of the cylindrical outer surface 32 of the header 30 . The ignition cup 68 has a frangible end wall 72 , which ruptures on ignition of the pyrotechnic charge 66 .
The igniter 24 further includes a housing 78 . The housing 78 is formed from an electrical insulation material. An electrical insulation material is a material that has a high resistance to the passage of current. Preferred electrical insulation materials are molded thermoplastics, such as nylon, and sintered ceramics, such as alumina or zirconia.
The housing 78 has a side wall 80 , which extends parallel to the central axis 42 of the igniter between an open end 82 and a closed end 84 of the housing 78 . The side wall 80 of the housing 78 has a cylindrical inner surface 86 , which extends from the open end 82 of the housing 78 to the closed end 84 . The cylindrical inner surface 86 and closed end 84 define a chamber 92 . The closed end 84 of the housing 78 has parallel cylindrical passages 88 and 90 that extend parallel to the igniter axis 42 through the closed end 84 of the housing 78 and open into the chamber 92 . The passages 88 and 90 receive the parallel electrodes 44 and 52 , respectively.
The header 30 is seated within the open end 82 of the housing 78 so that the header 30 closes the open end 82 , except for where the cylindrical opening 40 in the header 30 overlaps the open end 82 .
A body 60 of gas impermeable glass is positioned in the cylindrical opening 40 of the header 30 . The body 60 encircles the inner end 56 of the second electrode 52 and is encircled by a cylindrical inner surface 38 of the header 30 that defines the opening 40 . The body 60 of gas impermeable glass is positioned in the opening 40 , in a manner to be described, so that it fuses to and forms a gas-tight seal with the surface 38 and the inner end 56 of the second electrode 52 . The body 60 of gas impermeable glass electrically insulates the header 30 from the inner end 56 of the second electrode 52 .
A body 94 of electromagnetically lossy, substantially gas impermeable material is positioned within the chamber 92 of the housing 78 . The body 94 of electromagnetically lossy, substantially gas impermeable material is fused to and forms a gas-tight electromagnetically lossy seal with the inner surfaces 84 and 86 of the housing and the side 34 of the header 30 . The body 94 is also fused to and forms a gas-tight electromagnetically lossy seal with the portions of the first electrode 44 and the second electrode 52 that are encircled by the body 94 . The body 94 of electromagnetically lossy, substantially gas impermeable material electrically insulates the first electrode 44 from the second electrode 52 . Also, because it comprises an electromagnetically lossy filler, the body 94 provides RF attenuation for the igniter 24 .
In accordance with the present invention, the body 94 of electromagnetically lossy substantially gas impermeable material comprise a dense vitreous ceramic matrix. The matrix consists essentially of a glass binder and a electromagnetically lossy ferromagnetic and/or ferroelectric filler interspersed through the binder. The amount of binder is about 5% to about 50% by weight of the matrix. The amount of filler is about 50% to about 95% by weight of the matrix.
Preferred glass binders are lead borosilicate and lead aluminoborosilicate glasses, which include oxides of Al, B, Ba, Mg, Sb, Si, and Zn. These binders are commercially available in the form of finely ground frits. Examples of binders are CORNING (Corning, N.Y.) high temperature sealing glasses nos. 1415, 8165, and 8445, CORNING low temperature ferrite sealing glasses nos.1416, 1417, 7567, 7570, and 8463, and FERRO CORPORATION (Cleveland, Ohio) low temperature display sealing glasses nos. EG4000 and EG4010.
Preferred ferromagnetic fillers include spinal structured ferrites having the general formula (AaO) 1−x (BbO) x Fe 2 O 3 where Aa and Bb are divalent metal cations of Ba, Cd, Co, Cu, Fe, Mg, Mn, Ni, Sr, or Zn, and x is a fractional number in the semi-open interval [ 0 , 1 ). Examples of commercially available ferromagnetic fillers are FAIR-RITE PRODUCTS (Wallkill, N.Y.) nos. 73 and 43, which are sintered manganese-zinc and nickel-zinc spinal ferrite powders, respectively.
Preferred ferroelectric fillers include perovskite titanates having the general formula (XxO)TiO 2 and perovskite zirconates having the general formula (XxO)ZrO 2 where Xx denotes divalent metal cations of Ba, La, Sr, or Pb. Barium titanate, (BaO)TiO 2 , is a typical species. Other acceptable fillers include electrically lossy La-modified lead zirconium titanate perovskite ceramics known as PLZTs.
The body 94 is formed by first preparing an electromagnetically lossy ceramic mixture of 5-50% by weight of the glass binder and 50-95% by weight of the lossy ferromagnetic and/or ferroelectric filler. The mixing is performed wet in a polyethylene ball mill using a ceramic media such alumina or zirconia and a volatile organic carrier such as acetone having a forming agent such as polyvinyl acetate and a fatty acid dispersant such as menhaden fish oil. The resulting mixture is then dried. The dried mixture can be used in either a free-flowing form or as a vitreous preform. A vitreous preform is prepared by pouring the dried mixture into a mold having the desired configuration and heating the mixture to an elevated temperature effective to coalesce the mixture into a solid body.
The following Examples illustrate use of the dried mixture and assembly of the igniter.
EXAMPLE 1
In this Example, the non-conductive housing 78 is made of a thermoplastic, such as nylon.
A graphite mold/fixture is provided that has in the mold portion of the mold/fixture the desired configuration of the body 94 of glass. The first and second electrodes, 44 and 52 , and the header 30 are also positioned in the mold/fixture and held in fixed, preset desired positions in the mold/fixture. The dried mixture of electromagnetically lossy filler and glass binder is introduced into the mold/fixture as a vitreous preform. The vitreous preform fills the mold and encircles the electrodes 44 and 52 . A glass preform is introduced into the opening 40 . The glass preform fills the opening 40 and encircles the inner end 56 of the electrode 52 . The graphite mold/fixture, the mixture of electromagnetically lossy filler and glass binder, the glass preform, the electrodes 44 and 52 , and the header 30 are heated to a temperature above the glass working temperature of the glass binder and the glass preform (i.e. about 580° C. to about 800° C.). At this temperature, the electromagnetically lossy filler and glass binder as well as the glass preform soften or melt, wetting the surfaces of the electrodes 44 and 52 and the header 30 in contact with the electromagnetically lossy filler and binder and the glass preform. Upon cooling, the glass preform solidifies into the gas impermeable glass body 60 , and the electromagnetically lossy filler and binder coalesce into the electromagnetically lossy, substantially gas impermeable body 94 . The surfaces of the body 60 are chemically bonded to and form a gas-tight seal with the surface 38 of the header 30 and inner end 56 of the second electrode, which are contacted by the body 60 . The surfaces of the body 94 are chemically bonded to and form a gas-tight electromagnetically lossy seal with the surfaces of the electrodes 44 and 52 and the header 30 that are contacted by the body 94 .
The bridgewire 62 is welded to the inner end 56 of the second electrode 52 and the side 36 of the header. The pyrotechnic charge 66 is placed in the ignition cup 68 . The ignition cup 68 is attached to the header 30 so that the pyrotechnic charge 66 is in contact with the bridgewire 62 and the wall of the ignition cup overlies most of the outer surface 32 of the header 30 .
The graphite fixture is then removed and the electrodes 44 and 52 , the header 30 , the body 64 and the body 90 are placed in a second mold having a cavity shaped to the shape of the housing 78 . The material of the thermoplastic housing 78 is heated and flowed into the mold cavity around the now solid body 94 so that electrodes extend through the cylindrical passages 88 and 90 in the closed end 84 of the housing 78 . Upon cooling, the thermoplastic housing 78 becomes bonded to and forms a gas-tight electromagnetically lossy seal with the body 94 of electromagnetically lossy, substantially gas impermeable material, the ends 50 and 58 of the electrodes 44 and 52 , and the header 30 . The second mold is then removed from the housing.
EXAMPLE 2
This Example illustrates use of the dried mixture of glass binder and electromagnetically lossy filler when the housing 78 is made of a sintered ceramic such as alumina.
The vitreous preform of binder and electromagnetically lossy filler is seated in the housing 78 . The electrodes 44 and 52 and the header 30 are placed in the housing 78 so that the electrodes 44 and 52 extend through the cylindrical passages 88 and 90 in the closed end 84 of the housing 78 . A glass preform is seated in the opening 40 of the header 30 so that the inner end 56 of the second electrode 52 extends through the opening 40 . The housing 78 , the mixture of electromagnetically lossy filler and binder, the glass preform, the electrodes 44 and 52 , and the header 30 are heated to a temperature above the glass working temperature of the glass binder and the glass preform (i.e. about 580° C. to about 800° C.). At this temperature, the housing 78 retains its shape. Also, at this temperature, the electromagnetically lossy filler and glass binder as well as the glass preform soften or melt, wetting the surfaces of the housing 78 , electrodes 44 and 52 , and the header 30 in contact with the electromagnetically lossy filler and binder and the glass preform. Upon cooling, the glass preform solidifies into the gas impermeable glass body 60 , and the electromagnetically lossy filler and binder coalesce into the electromagnetically lossy substantially, gas impermeable body 94 . The surfaces of the body 60 of gas impermeable glass are chemically bonded to and form a gas-tight seal with the surface 38 of the header 30 and inner end 56 of the second electrode, which are contacted by the body 60 . The surfaces of the body 94 are chemically bonded to and form a gas-tight electromagnetically lossy seal with the surfaces of the housing 78 , electrodes 44 and 52 , and header 30 that are contacted by the second body 94 .
The bridgewire 62 is welded to the inner end 56 of the second electrode 52 and the side 36 of the header. The pyrotechnic charge 66 is placed in the ignition cup 68 . The ignition cup 68 is attached to the header 30 so that the pyrotechnic charge 66 is in contact with the bridgewire 62 and the wall of the ignition cup overlies most of the outer surface 32 of the header 30 .
From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.
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A pyrotechnic device comprises a body of ignitable material ( 66 ). A pair of electrodes ( 44 ) and ( 52 ) provide electrical energy to heat and ignite the body of pyrotechnic material ( 66 ). The electrodes ( 44 ) and ( 52 ) extend through an electrical insulation housing ( 78 ). The electrical insulation housing ( 78 ) has surfaces defining a chamber ( 92 ) through which the electrodes ( 44 ) and ( 52 ) pass. A body ( 94 ) of a solid electromagnetically lossy, substantially gas impermeable material is positioned within the chamber ( 92 ). The lossy material comprises a vitreous ceramic matrix consisting essentially of about 5% to about 50% by weight of a multi-component glass binder and about 50% to about 95% by weight of an electromagnetically lossy ferromagnetic and/or ferroelectric filler. The body ( 94 ) of lossy material is fused to the surfaces defining the chamber ( 92 ) in the electrical insulation housing ( 78 ) and to the electrodes ( 44 ) and ( 52 ).
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BACKGROUND OF THE INVENTION
A sweep frequency generator provides an output signal which is maintained at a basic or starting frequency and periodically sweeps linearly through a given frequency range. High linearity sweep frequency generators are used in spectrum analyzers, detection and surveillance receivers, and similar type devices for electrically sweeping through a desired range of frequencies. In general, the accuracy of the apparatus is dependent upon the linearity of the sweep from the generator.
In the prior art, many schemes have been devised for including a variable frequency oscillator in a feedback loop to correct the linearity. An example of one such scheme is described in U.S. Pat. No. 3,382,460, entitled "Linearly Swept Frequency Generator", patented May 7, 1968. In the patent described, the output of a voltage controlled oscillator is sampled at intervals, generally at an integral number of cycles, and, if the generator output frequency changes at the correct rate the sampled phases will all be identical. Any variation in the sampled phase is applied to the oscillator as an error signal. This sampling of the output frequency with time leaves room for error and can be a relatively complicated timing problem. Further, because of the periodic sampling at integral numbers of cycles and the inherent timing problems, this system becomes difficult at high speeds.
SUMMARY OF THE INVENTION
The present invention pertains to a constant rate sweep frequency generator including a variable frequency oscillator with a nonlinear element for varying the frequency with a phase lock loop attached to the nonlinear element for controlling the frequency of the oscillator between sweeps, or during retrace, and a sweep generator attached to the nonlinear element of the oscillator during the sweeps with a rate error loop also attached to the oscillator for continuously sensing the rate linearity of the output signal and adding a signal to the output of the sweep generator to maintain a constant rate of change of the signal out of the oscillator.
It is an object of the present invention to provide a new and improved constant rate sweep frequency generator.
It is a further object of the present invention to provide a constant rate sweep frequency generator embodying a relatively simple, low cost analog technique.
It is a further object of the present invention to provide a constant rate sweep frequency generator which is capable of providing a relatively high sweep rate and sweep repetition rate.
These and other objects of this invention will become apparent to those skilled in the art upon consideration of the accompanying specification, claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings:
FIG. 1 is a block diagram of a constant rate sweep frequency generator embodying the present invention; and
FIG. 2 illustrates several waveforms that appear at various points in the diagram of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the present embodiment a variable frequency oscillator, such as voltage controlled oscillator 10 which may include a nonlinear element, such as a Varicap or the like, for tuning in response to a voltage applied thereto, has a control input 11 and a sweep frequency output 12. A portion of the output signal from the oscillator 10 is coupled by a sensing device 13 to one input of a phase detector 15. A second input of the phase detector 15 has a reference generator 16 connected thereto and the output of the phase detector 15 is connected through a loop filter 17 and gate 18 to one input of a summing device 20. An output of the summing device 20 is connected to the control input 11 of the voltage controlled oscillator 10. The voltage controlled oscillator 10, phase detector 15, reference generator 16 and loop filter 17 form a conventional phase locked loop which, when the gate 18 is closed, phase locks the output of the voltage controlled oscillator 10 to the reference frequency from the reference generator 16.
A portion of the output of the voltage controlled oscillator 10 is also coupled by way of a second sensing device 25 to a time delay means 26. The delay means 26 may simply be a linear delay line or the like which delays the input signal thereto by a predetermined amount and provides a signal at the output which is an exact duplicate of the input signal, but delayed in time. The delayed output signal from the delay means 26 is applied to one input of a mixer 27 and a portion of the signal from the sensing device 25 is coupled to a second input of the mixer 27 by a sensing device 30. The output of the mixer 27 is applied through a filter-limiter 31 to a discriminator 32. The discriminator 32 is a standard discriminator, such as a Foster-Seeley or the like, and supplies a signal at the output thereof which is a DC signal that varies as a function of frequency. The signal from the discriminator 32 is supplied through a loop filter 33 and gate 34 to a second input of the summing device 20.
The gate 18 and the gate 34 are operated by signals from a retrace interval generator 40 and a sweep interval generator 41, respectively. The output from the retrace interval generator 40 is also utilized to trigger the sweep interval generator 41 and the output of the sweep interval generator 41 is also used to trigger the retrace interval generator 40 and a sweep generator 42. The retrace and sweep interval generators 40 and 41 are so interconnected that when one is supplying a positive gating signal the other is off and vice versa. Thus, the retrace interval generator 40 closes the gate 18 while the sweep interval generator 41 maintains the gate 34 open and the sweep generator 42 off. Further, when the sweep interval generator 41 turns the sweep generator 42 on and closes the gate 34 the retrace interval generator 40 opens the gate 18. It will be obvious to one skilled in the art that the retrace and sweep interval generators 40 and 41 could be embodied in a single device, such as a multivibrator or the like. The output signals from the retrace and sweep interval generators 40 and 41 are illustrated in FIG. 2 and labeled accordingly. The output of the sweep generator 42 is supplied to a third input of the summing device 20.
In the operation of the generator illustrated in FIG. 1, the retrace interval generator 40 closes the gate 18 to complete the phase lock loop and the sweep interval generator 41 turns off the sweep generator 42 and opens the gate 34. The phase lock loop then locks the output of the oscillator 10 to the output of the reference generator 16. After a short period of time the retrace and sweep interval generators 40 and 41 switch so that the gate 18 is opened and the gate 34 is closed while the sweep generator 42 is turned on. As the sweep generator 42 supplies a sweep signal to the control input 11 of the oscillator 10, the output of the oscillator 10 begins to change, or sweep through the desired range. The output is applied directly to one input of the mixer 27 while a delayed output is applied to the second input thereof. If the output signal rate of change from the oscillator 10 is linear the direct signal and the delayed signal applied to the mixer 27 will produce a constant frequency signal at the output thereof, which will produce a zero error voltage at the output of the discriminator 32. Any nonlinearities in the output signal from the oscillator 10 will appear as a frequency change at the output of the mixer 27 and will be converted to a DC signal varying as a function of frequency error at the output of the discriminator 32. This DC signal will be added to the output of the sweep generator 42 in the summing device 20. In general, since the frequency controlling device in the oscillator 10 will be a nonlinear device, such as a Varicap or the like, the signal applied to the control input 11 will be a nonlinear signal, generally as illustrated in FIG. 2 (labeled Summing Output). Each time the sweep stops and a retrace begins, the retrace and sweep interval generators 40 and 41 switch to connect the oscillator 10 into the phase lock loop so that the basic frequency is locked to the reference generator 16.
Thus, the generator disclosed is periodically locked onto a reference frequency to ensure the correct initial operating frequency, and the linearity of the sweep is continuously monitored during the sweep to ensure a constant rate. Further, because of the continuous monitoring of the rate, the sweep linearity is only dependent upon the capability of the rate error loop and not inhibited by complicated timing and the like.
While we have shown and described a specific embodiment of this invention, further modifications and improvements will occur to those skilled in the art. We desire it to be understood, therefore, that this invention is not limited to the particular form shown and we intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.
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A variable frequency oscillator including a nonlinear element for varying the frequency has alternately attached thereto a phase lock loop for maintaining the base or starting frequency of the oscillator substantially constant, and a sweep generator with a rate error loop for sensing the frequency linearity of the output sweep and altering the input signal to maintain the output linear.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims benefit of U.S. Provisional Patent Application 60/982,357, filed Oct. 24, 2007, for Electrode Array for Even Retinal Pressure. This application is related to and incorporates by reference, U.S. patent application Ser. No. 12/163,658, filed Jun. 27, 2008, for Flexible Circuit Electrode Array.
GOVERNMENT RIGHTS NOTICE
This invention was made with government support under grant No. R24EY12893-01, awarded by the National Institutes of Health. The government has certain rights in the invention.
FIELD OF THE INVENTION
The present invention is generally directed to neural stimulation and more specifically to an improved method of improving resolution by selectively stimulating smaller cells.
BACKGROUND OF THE INVENTION
In 1755 LeRoy passed the discharge of a Leyden jar through the orbit of a man who was blind from cataract and the patient saw “flames passing rapidly downwards.” Ever since, there has been a fascination with electrically elicited visual perception. The general concept of electrical stimulation of retinal cells to produce these flashes of light or phosphenes has been known for quite some time. Based on these general principles, some early attempts at devising a prosthesis for aiding the visually impaired have included attaching electrodes to the head or eyelids of patients. While some of these early attempts met with some limited success, these early prosthetic devices were large, bulky and could not produce adequate simulated vision to truly aid the visually impaired.
In the early 1930's, Foerster investigated the effect of electrically stimulating the exposed occipital pole of one cerebral hemisphere. He found that, when a point at the extreme occipital pole was stimulated, the patient perceived a small spot of light directly in front and motionless (a phosphene). Subsequently, Brindley and Lewin (1968) thoroughly studied electrical stimulation of the human occipital (visual) cortex. By varying the stimulation parameters, these investigators described in detail the location of the phosphenes produced relative to the specific region of the occipital cortex stimulated. These experiments demonstrated: (1) the consistent shape and position of phosphenes; (2) that increased stimulation pulse duration made phosphenes brighter; and (3) that there was no detectable interaction between neighboring electrodes which were as close as 2.4 mm apart.
As intraocular surgical techniques have advanced, it has become possible to apply stimulation on small groups and even on individual retinal cells to generate focused phosphenes through devices implanted within the eye itself. This has sparked renewed interest in developing methods and apparati to aid the visually impaired. Specifically, great effort has been expended in the area of intraocular retinal prosthesis devices in an effort to restore vision in cases where blindness is caused by photoreceptor degenerative retinal diseases such as retinitis pigmentosa and age related macular degeneration which affect millions of people worldwide.
Neural tissue can be artificially stimulated and activated by prosthetic devices that pass pulses of electrical current through electrodes on such a device. The passage of current causes changes in electrical potentials across retinal neuronal cell membranes, which can initiate retinal neuronal action potentials, which are the means of information transfer in the nervous system.
Based on this mechanism, it is possible to input information into the nervous system by coding the sensory information as a sequence of electrical pulses which are relayed to the nervous system via the prosthetic device. In this way, it is possible to provide artificial sensations including vision.
Some forms of blindness involve selective loss of the light sensitive transducers of the retina. Other retinal neurons remain viable, however, and may be activated in the manner described above by placement of a prosthetic electrode device on the inner (toward the vitreous) retinal surface (epiretinal). This placement must be mechanically stable, minimize the distance between the device electrodes and the retinal neurons, and avoid undue compression of the retinal neurons.
In 1986, Bullara (U.S. Pat. No. 4,573,481) patented an electrode assembly for surgical implantation on a nerve. The matrix was silicone with embedded iridium electrodes. The assembly fit around a nerve to stimulate it.
Dawson and Radtke stimulated a cat's retina by direct electrical stimulation of the retinal ganglion cell layer. These experimenters placed nine and then fourteen electrodes upon the inner retinal layer (i.e., primarily the ganglion cell layer) of two cats. Their experiments suggested that electrical stimulation of the retina with 30 to 100 uA current resulted in visual cortical responses. These experiments were carried out with needle-shaped electrodes that penetrated the surface of the retina (see also U.S. Pat. No. 4,628,933 to Michelson).
The Michelson '933 apparatus includes an array of photosensitive devices on its surface that are connected to a plurality of electrodes positioned on the opposite surface of the device to stimulate the retina. These electrodes are disposed to form an array similar to a “bed of nails” having conductors which impinge directly on the retina to stimulate the retinal cells. U.S. Pat. No. 4,837,049 to Byers describes spike electrodes for neural stimulation. Each spike electrode pierces neural tissue for better electrical contact. U.S. Pat. No. 5,215,088 to Norman describes an array of spike electrodes for cortical stimulation. Each spike pierces cortical tissue for better electrical contact.
The art of implanting an intraocular prosthetic device to electrically stimulate the retina was advanced with the introduction of retinal tacks in retinal surgery. De Juan, et al. at Duke University Eye Center inserted retinal tacks into retinas in an effort to reattach retinas that had detached from the underlying choroid, which is the source of blood supply for the outer retina and thus the photoreceptors. See, e.g., E. de Juan, et al., 99 Am. J. Opthalmol. 272 (1985). These retinal tacks have proved to be biocompatible and remain embedded in the retina, and choroid/sclera, effectively pinning the retina against the choroid and the posterior aspects of the globe. Retinal tacks are one way to attach a retinal electrode array to the retina. U.S. Pat. No. 5,109,844 to de Juan describes a flat electrode array placed against the retina for visual stimulation. U.S. Pat. No. 5,935,155 to Humayun describes a retinal prosthesis for use with the flat retinal array described in de Juan.
SUMMARY OF THE INVENTION
The present invention is a visual prosthesis having an electrode array suitable to be positioned on the retina. The array includes multiple attachment points to provide for even pressure across the electrode array surface. The attachment points are arranged so as to not damage retinal tissue stimulated by the electrode array.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts the electrode array of the preferred embodiment.
FIG. 2 depicts an electrode array of an alternate two point attachment
FIG. 3 depicts an electrode array of an alternate three point attachment.
FIG. 4 depicts an electrode array with another alternate three point attachment.
FIG. 5 is a perspective view of the implanted portion of the preferred visual prosthesis.
FIG. 6 is a side view of the implanted portion of the preferred visual prosthesis showing the fan tail in more detail.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims.
FIG. 1 shows the flexible circuit electrode array of the current invention. A flexible circuit cable 112 connects to the flexible circuit electrode array 110 . Further, a primary attachment point 54 is provided near the heel of the flexible circuit electrode array 110 . A retina tack (not shown) is placed through the primary attachment point 54 to hold the flexible circuit electrode array 110 to the retina or other neural tissue. A stress relief 55 is provided surrounding the attachment point 54 . The stress relief 55 may be made of a softer polymer than the flexible circuit, or it may include cutouts or thinning of the polymer to reduce the stress transmitted from the retina tack to the flexible circuit electrode array 110 . A skirt or molded body 60 covers the flexible circuit electrode array 10 , and extends beyond its edges. It is further advantageous to include wings 62 adjacent to the attachment point 54 to spread any stress of attachment over a larger area of the retina or other neural tissue. There are several ways of forming and bonding the skirt 60 . The skirt 60 may be directly bonded through surface activation or indirectly bonded using an adhesive. The skirt 60 may be a molded body from completely around the electrode array 110 and cable 112 .
Preferably the electrode array 110 is constructed from a hard polymer such as polyimide while the skirt 60 is constructed from a softer polymer such as silicone. Traces and electrodes can be laid out on a hard polymer by photolithography and the hard polymer protects the delicate traces. A soft polymer skirt or molded body 60 then protects the neural tissue from the hard polymer.
Further a strap 20 may be provided over the array 110 opposite the primary attachment point 54 attached at either end by secondary attachment points 22 with retinal tacks. The secondary attachment points 22 include stress relief 24 like the stress relief 55 described above. Retinal nerve fibers and blood vessels run orbitally out from the optic nerve. It is advantageous not to tack between the electrode array 110 and the optic nerve as you may damage the nerve fibers which are stimulated by the electrode array 110 . The strap 20 allows the secondary attachment points 22 to be out of the line of the stimulated nerve fibers. The optic nerve 30 is the central access point for both nerve fibers and blood vessels. 32 . A tack through either a nerve fiber or blood vessel may cause damage to the area to be stimulated by the electrode array 110 .
Alternatively, FIG. 2 show a central secondary attachment point 26 , with a stress relief 28 . If the array is not aligned with the nerve fibers a central secondary attachment point may be preferable.
FIG. 3 show a second alternate embodiment. It this case the array may be place in the opposite orientation, with the cable passing over the optic nerve. The primary attachment point 40 includes a stress relief 42 . The secondary attachment points 44 , with stress relief 48 , are included in the wings 62 .
FIG. 4 shows another alternate embodiment similar to the embodiment shown in FIG. 1 , but with the secondary attachment points 26 integral to the array body rather than on a separate strap. As with the embodiment of FIG. 1 , the secondary attachment points are outside of the area of the nerve fibers and blood vessels supplying the areas to be stimulated.
FIG. 5 shows a perspective view of the implanted portion of the preferred retinal prosthesis. An electrode array 110 is mounted by a retinal tack or similar means to the epiretinal surface. The electrode array 110 is electrically coupled by a cable 112 , which pierces the sclera and is electrically coupled to an electronics package 114 , external to the sclera.
The electronics package 114 is electrically coupled to a secondary inductive coil 116 . Preferably the secondary inductive coil 116 is made from wound wire. Alternatively, the secondary inductive coil may be made from a thin film polymer sandwich with wire traces deposited between layers of thin film polymer. The electronics package 114 and secondary inductive coil 116 are held together by a molded body 118 . The molded body 118 may also include suture tabs 120 . The molded body narrows to form a strap 122 which surrounds the sclera and holds the molded body 118 , secondary inductive coil 116 , and electronics package 114 in place. The molded body 118 , suture tabs 120 and strap 122 are preferably an integrated unit made of silicone elastomer. Silicone elastomer can be formed in a pre-curved shape to match the curvature of a typical sclera. However, silicone remains flexible enough to accommodate implantation and to adapt to variations in the curvature of an individual sclera. The secondary inductive coil 116 and molded body 118 are preferably oval shaped. A strap can better support an oval shaped coil.
It should be noted that the entire implant is attached to and supported by the sclera. An eye moves constantly. The eye moves to scan a scene and also has a jitter motion to prevent image stabilization. Even though such motion is useless in the blind, it often continues long after a person has lost their sight. It is an advantage of the present design, that the entire implanted portion of the prosthesis is attached to and supported by the sclera. By placing the device under the rectus muscles with the electronics package in an area of fatty issue between the rectus muscles, eye motion does not cause any flexing which might fatigue, and eventually damage, the device.
FIG. 6 shows a side view of the implanted portion of the retinal prosthesis, in particular, emphasizing the fan tail 124 . When implanting the retinal prosthesis, it is necessary to pass the strap 122 under the eye muscles to surround the sclera. The secondary inductive coil 116 and molded body 118 must also follow the strap under the lateral rectus muscle on the side of the sclera. The implanted portion of the retinal prosthesis is very delicate. It is easy to tear the molded body 118 or break wires in the secondary inductive coil 116 . In order to allow the molded body 118 to slide smoothly under the lateral rectus muscle, the molded body is shaped in the form of a fan tail 124 on the end opposite the electronics package 114 .
Accordingly, what has been shown is an improved method of making a neural prosthesis and an improved method of stimulating neural tissue. While the invention has been described by means of specific embodiments and applications thereof, it is understood that numerous modifications and variations could be made thereto by those skilled in the art without departing from the spirit and scope of the invention. In particular, the preferred embodiment describes a retinal prosthesis for artificial vision. It should be obvious to one skilled in the art that the invention has broad applicability to other types of neural stimulation. It is therefore to be understood that within the scope of the claims, the invention may be practiced otherwise than as specifically described herein.
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The present invention is an electrode array for neural stimulation. In particular it is an electrode array for use with a visual prosthesis with the electrode array suitable to be positioned on the retina. The array includes multiple attachment points to provide for even pressure across the electrode array surface. The attachment points are arranged so as to not damage retinal tissue stimulated by the electrode array.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a division of U.S. patent application Ser. No. 14/429,684, filed 9 Mar. 2015, which is currently pending. U.S. patent application Ser. No. 14/429,684 is a national stage of Int. Pat. App. No. PCT/US14/32553, filed 1 Apr. 2014, which is abandoned. Int. Pat. App. No. PCT/US14/32553 cites the priority of U.S. patent application Ser. No. 61/819,097, filed 3 May 2013, which is expired. The disclosures of both of U.S. patent application Ser. No. 14/429,684 and Int. Pat. App. No. PCT/US14/32553 are incorporated herein in their entireties; the prosecution histories of these applications are not incorporated by reference.
BACKGROUND
[0002] A. Field of the Disclosure
[0003] The present disclosure relates generally to the treatment of urological disorders. Methods of treating such disorders, implants for the treatment of such disorders, and methods of using said implants, are provided.
[0004] B. Background
[0005] The muscles and ligaments that form the pelvic floor serve two critical functions in female physiology: controlling the flow of urine from the bladder and maintaining the positions of pelvic organs. When the floor weakens, is injured, stretches, or atrophies, the result can be urinary incontinence (UI) and pelvic organ prolapse (POP). POP is the descending or drooping of pelvic organs, such as the bladder, uterus, vagina, small bowel, and rectum. When it occurs, POP can result in the movement of one or more pelvic organs into another organ, for example prolapse of the bladder into the vagina. Other pelvic floor disorders include vaginal prolapse, vaginal hernia, rectocele, enterocele, uterocele, and urethrocele. POP and urinary incontinence are relatively common (about 30% of women in the United States experience some degree of pelvic organ prolapse in their lifetimes, and about 12% of U.S. women aged 60-64 experience urinary incontinence on a daily basis).
[0006] Pelvic floor disorders often cause or exacerbate female urinary incontinence. One type of urinary incontinence, called stress urinary incontinence, effects primarily women and is often caused by two conditions: intrinsic sphincter deficiency (ISD) and hypermobility. These conditions may occur independently or in combination. In ISD, the urinary sphincter valve, located within the urethra, fails to close properly, causing urine to leak out of the urethra during stressful activity. In hypermobility, the pelvic floor is distended, weakened, or damaged. When the afflicted woman sneezes, coughs, or otherwise strains the pelvic region, the bladder neck and proximal urethra rotate and descend. As a result, the urethra does not close with sufficient response time, and urine leaks through the urethra.
[0007] Various techniques have been used to anchor the pelvic organs to treat prolapse and to compress or support the urethra to prevent urinary incontinence. However, the performance of these traditional surgical techniques for these purposes has been poor.
[0008] Traditionally, both of these problems were fixed by repairing the patient's own tissue defects or by placing a non-synthetic implant underneath the urethra through an abdominal incision alone or in combination with a transvaginal incision. However, these approaches had unacceptable failure rates, long surgical times, long hospital stays, and significant post-operative pain. They were also criticized for requiring the patient's own tissues for support (specifically, the periurethral and perivesical fascia), which had the disadvantages of requiring that implants be custom fitted to the specific patient's dimensions and requiring that the patient had tissues of adequate strength. In addition, this approach used grafted tissue to form the implant, which in some cases would degrade with time.
[0009] In the late 1990s a new procedure was introduced for treating incontinence involving the insertion of a sling around the urethra made of synthetic mesh. The “mid-urethral sling” gained instant popularity over traditional transabdominal approaches and graft suburethral slings. It was simple to insert; the suburethral mesh sling could be introduced through a small transvaginal incision during an outpatient procedure in less than an hour. It required only a short recovery time with less postoperative pain. The synthetic mesh maintained its integrity over time and proved to be more durable than the patient's own tissue or cadaver tissue. The previously described techniques declined in number or were abandoned.
[0010] Unfortunately the new approach proved to have serious long-term side effects. The placement of the mesh posterior to the urethra creates a situation in which the mesh can press into the vagina, causing symptoms such as dyspareunia (painful intercourse), pelvic pain, anterior vaginal thinning, and erosion of the mesh into the vagina. These side effects can only be resolved by another procedure to remove the mesh. As a result, the patient often suffers worse symptoms than she did before the first procedure.
[0011] Consequently there is a need for a transabdominal approach to using non-absorbable material to treat POP and UI without the serious risks associated with the transvaginal approach.
SUMMARY
[0012] This application provides methods and devices to address the needs in the art discussed above; although it is to be understood that not every embodiment of such methods and devices will address any or all such problems.
[0013] A surgical implant for maintaining the position of a patient's urethra is provided. A general embodiment of the implant comprises: a proximal portion having a width, length, and thickness, the width of the proximal portion being at least 4× its length and at least 100× its thickness, the proximal portion comprising a first non-absorbable biocompatible material; and a distal portion having a width, length, and thickness, the width of the distal portion being no more than 0.25× the width of the proximal portion, and the thickness of the distal portion being no more than 0.01× the width of the proximal portion, the distal portion comprising a second non-absorbable biocompatible material.
[0014] Another general embodiment of the implant comprises: a proximal portion having a first width, a first length, and a first thickness, comprising a first non-absorbable biocompatible material; and a distal portion having a second width, a second length, and a second thickness comprising a second non-absorbable biocompatible material; wherein the ratio of the first width to the second width is at least the ratio of the distance between a given human's right and left pectineal ligament to the distance between the given human's right and left periurethral fascia.
[0015] A method of emplacing a surgical implant against the anterior urethra of a subject is also provided, the method comprising: anchoring the proximal portion of an implant to the right pelvic fascia of the subject and to the left pelvic fascia of the subject so that the implant is positioned between the bladder and the pubic bone and in contact with the anterior surface of the bladder; and anchoring the distal portion of the implant to the periurethral fascia of the subject; so that the distal portion of the implant contacts the anterior surface of at least one structure selected from: the bladder neck and the proximal urethra.
[0016] A method of supporting the proximal urethra or bladder neck of a subject is also provided, comprising fixating at least one of the proximal urethra and the bladder neck, from the anterior side.
[0017] The above presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key or critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 : Illustration of an embodiment of the implant (shown in silhouette) placed against the anterior surface of the bladder neck of an adult human female as seen through an anterior incision through the lower abdomen. The patient's anatomy is labeled as follows: A is the obturator internus, B is the pubic bone, C is the pubic symphysis, D is the endopelvic fascia, E is the periurethral fascia, F is the arcus tendineus, and G is the bladder.
[0019] FIG. 2 : Top view of an exemplary embodiment of the implant, with some potential anchor points marked as Xs.
[0020] FIG. 3 : Top view of another exemplary embodiment of the implant. Potential anchor points for suture fixation to structures such as the periurethral fascia, the pelvic fascia, and the anterior bladder shown as Xs.
[0021] FIG. 4 : Detail view of the expandable body of an exemplary embodiment of the implant.
[0022] FIG. 5 : Side view (sagittal cutaway) of an exemplary placement of an embodiment of the implant on the urethra when the expandable member is in its non-expanded configuration. The patient's anatomy is labeled as follows: G is the bladder, H is the pubic bone, I is the urethra, and J is the vagina.
[0023] FIG. 6 : Side view (sagittal cutaway) of the exemplary placement of the embodiment of the implant shown in FIG. 5 when the expandable member is in its expanded configuration. The patient's anatomy is labeled using the same reference characters as in FIG. 5 .
[0024] FIG. 7 : Front view of an exemplary placement of an embodiment of the implant overlying the proximal urethra, bladder neck, and portion of the bladder. The patient's anatomy is labeled as follows: G is the bladder, I is the urethra, and K is the bony pelvis.
[0025] FIG. 8 : Perspective view of the exemplary placement shown in FIG. 7 . The patient's anatomy is labeled using the same reference characters as in FIG. 7 .
[0026] FIG. 9 : Perspective view of an embodiment of the implant comprising a loop of suburethral graft. The patient's anatomy is labeled using the same reference characters as in FIG. 7 .
[0027] FIG. 10 : Illustration of an embodiment of the implant (shown in silhouette) configured to be deployed with a loop of suburethral graft placed against the anterior surface of the bladder neck of an adult human female as seen through an anterior incision through the lower abdomen. The patient's anatomy is labeled using the same reference characters as in FIG. 1 .
DETAILED DESCRIPTION
A. Definitions
[0028] With reference to the use of the word(s) “comprise” or “comprises” or “comprising” in the foregoing description and/or in the following claims, unless the context requires otherwise, those words are used on the basis and clear understanding that they are to be interpreted inclusively, rather than exclusively, and that each of those words is to be so interpreted in construing the foregoing description and/or the following claims.
[0029] The term “consisting essentially of” means that, in addition to the recited elements, what is claimed may also contain other elements (steps, structures, ingredients, components, etc.) that do not adversely affect the operability of what is claimed for its intended purpose. Such addition of other elements that do not adversely affect the operability of what is claimed for its intended purpose would not constitute a material change in the basic and novel characteristics of what is claimed.
[0030] The terms “prevention”, “prevent”, “preventing”, “suppression”, “suppress” and “suppressing” as used herein refer to a course of action (such as implanting a medical device) initiated prior to the onset of a clinical manifestation of a disease state or condition so as to prevent or reduce such clinical manifestation of the disease state or condition. Such preventing and suppressing need not be absolute to be useful.
[0031] The terms “treatment”, “treat” and “treating” as used herein refers to a course of action (such as implanting a medical device) initiated after the onset of a clinical manifestation of a disease state or condition so as to eliminate or reduce such clinical manifestation of the disease state or condition. Such treating need not be absolute to be useful.
[0032] The term “in need of treatment” as used herein refers to a judgment made by a caregiver that a patient requires or will benefit from treatment. This judgment is made based on a variety of factors that are in the realm of a caregiver's expertise, but that includes the knowledge that the patient is ill, or will be ill, as the result of a condition that is treatable by a method or device of the present disclosure.
[0033] The term “in need of prevention” as used herein refers to a judgment made by a caregiver that a patient requires or will benefit from prevention. This judgment is made based on a variety of factors that are in the realm of a caregiver's expertise, but that includes the knowledge that the patient will be ill or may become ill, as the result of a condition that is preventable by a method or device of the disclosure.
[0034] The term “individual”, “subject” or “patient” as used herein refers to any animal, including mammals, such as mice, rats, other rodents, rabbits, dogs, cats, swine, cattle, sheep, horses, or primates, and humans. The term may specify male or female or both, or exclude male or female.
[0035] The terms “about” and “approximately” shall generally mean an acceptable degree of error or variation for the quantity measured given the nature or precision of the measurements. Typical, exemplary degrees of error or variation are within 20 percent (%), preferably within 10%, and more preferably within 5% of a given value or range of values. For biological systems, the term “about” refers to an acceptable standard deviation of error, preferably not more than fold of a given value. Numerical quantities given herein are approximate unless stated otherwise, meaning that the term “about” or “approximately” can be inferred when not expressly stated.
B. Surgical Implant
[0036] A surgical implant 100 is provided with a relatively wide proximal portion 1100 and a relatively narrow distal portion 1200 . The implant 100 can be used to maintain the position of a subject's urethra, compress the subject's urethra (for example to treat or prevent urinary incontinence), or both. The implant 100 is also useful to maintain the position of one or both of the bladder or the bladder neck. The implant 100 may be used to position or compress any portion of the urethra, but in particular embodiments the implant 100 is used to position or compress the proximal urethra. Any description herein that refers to the urethra generally may be construed to pertain to the proximal urethra specifically (although not to the exclusion of referring to the urethra generally). The implant 100 is configured to be anchored to the subject's pelvic fascia by the proximal portion 1100 , so that the distal portion 1200 overlays and contacts the anterior surface of the urethra, as seen in the exemplary embodiment illustrated in FIG. 1 .
[0037] In a general embodiment, the implant 100 comprises: a proximal portion 1100 having a width, length, and thickness, the width of the proximal portion 1100 being at least 4× its length and at least one hundred times (100×) its thickness, the proximal portion 1100 comprising a first non-absorbable biocompatible material; and a distal portion 1200 having a width, length, and thickness, the width of the distal portion 1200 being no more than one quarter (0.25×) the width of the proximal portion 1100 , and the thickness of the distal portion 1200 being no more than one hundredth (0.01×) the width of the proximal portion 1100 , the distal portion 1200 comprising a second non-absorbable biocompatible material.
[0038] In another general embodiment, the implant 100 comprises: a proximal portion 1100 having a first width, a first length, and a first thickness, comprising a first non-absorbable biocompatible material; and a distal portion 1200 having a second width, a second length, and a second thickness comprising the second non-absorbable biocompatible material; wherein the ratio of the first width to the second width is at least the ratio of the distance between a given human's right and left pectineal ligament to the distance between the given human's right and left periurethral fascia.
[0039] Given such dimensions, the implant 100 should be suitable for use on most female subjects, regardless of the absolute (as opposed to relative) size of the subject.
[0040] In some embodiments of the implant 100 one or both of the proximal or distal portions 1100 and 1200 are substantially non-elastic. In this context “non-elastic” refers to a relatively high Young's modulus, i.e., the proximal or distal portion 1100 & 1200 will not deform along an axis when opposing forces are applied along the axis. In this context polypropylene is considered to have a high Young's modulus (1.5-2.0 GPa), compared to rubber (0.01-0.1 GPa) and PTFE (0.5 GPa). Thus, in such embodiments the proximal and/or distal portion 1100 and 1200 will not tend to stretch when pulled in two opposite directions. A substantially non-elastic portion has the advantages of providing stronger support for the urethra and providing a rigid backing for the expandable member 1300 described below.
[0041] This is separate and distinct from the portion's flexibility. In some embodiments of the implant 100 one or both of the proximal or distal portions 1100 and 1200 will be flexible, regardless of whether said portion of the implant 100 is non-elastic. Although elasticity and flexibility sometimes go hand-in-hand, this is not the case for many types of materials. Everyday examples of materials with high flexibility but low elasticity are cotton textile fabrics; due to their fibrous construction they readily bend and fold, but if pulled in two opposite directions they do not stretch. Flexible portions have the advantage of being much easier to implant due to their ability to readily conform to the contours of the subject's body.
[0042] Accordingly, some embodiments of the first and second non-absorbable biocompatible material are flexible; some embodiments are substantially non-elastic; further embodiments are flexible and substantially non-elastic.
[0043] Suitable materials for such implants are known in the art. The implant 100 must be constructed from a non-absorbent biocompatible material. For example, one or both of the first and second non-absorbable biocompatible materials may be silicone (including stamped silicone), polymer fabric, or surgical mesh. One suitable type of polymer fabric is GORE-TEX (expanded polytetrafluoroethylene fabric). Various types of surgical mesh may be used, such as Type I macroporous mesh (pore size>75 μm), Type II microporous mesh (pore size<10 μm), and Type III macroporous mesh with multifilamentous filaments (pore size>75 μm). The materials for such meshes are known in the art. Examples include polypropylene, polyethylene, polytetrafluoroethylene, polyester (such as MERSILENE), SURGIPRO (polypropylene), PROLENE (polypropylene), or MARLEX (crystalline polypropylene and high-density polyethylene). In a specific embodiment the non-absorbent biocompatible material is Type I macroporous polypropylene mesh. The proximal and distal portions 1100 and 1200 may be constructed from different non-absorbent biocompatible materials, or they may be made from the same material. Using the same material has the advantage of ease of construction. Using different materials allows tailoring of the properties of each portion.
[0044] The dimensions of the implant 100 are suitable to anchor the proximal portion 1100 of the implant 100 to the pelvic fascia, to anchor the distal portion 1200 of the implant 100 to the periurethral fascia, and to contact the anterior surface of the urethra. Of course individual subjects vary in size, and to a lesser extent the relative dimensions of individual subjects vary as well. Nonetheless, one of ordinary skill in the art will have an understanding of the typical dimensions of a subject (including adult subjects, pediatric subjects, etc.) as well as an understanding of the upper and lower bounds of human variation in the relevant dimensions. The structure(s) in question may be a typical adult structure(s). Alternatively, the structure(s) in question may be wider or narrower than usual, but within the normal range for a human adult. In other embodiments of the implant 100 the structure(s) in question may deviate from the range of adult norms; for example in the case of a pediatric subject, a subject displaying dwarfism, and a subject displaying gigantism.
[0045] The proximal and distal portions 1100 and 1200 may be sufficiently thin to allow them to be implanted without altering the anatomical orientation of the subject's anatomy. In a specific embodiment of the implant 100 the thickness of one or both of the proximal portion 1100 and the distal portion 1200 is no more than about 1 mm. A thickness of 1 mm should be a suitable thickness for most subjects.
[0046] The distal portion 1200 is intended to cover a section of the subject's urethra (and optionally a portion of the bladder neck as well). Accordingly, some embodiments of the distal portion 1200 of the implant 100 have a width greater than the width of an adult human urethra.
[0047] The distal portion 1200 is also intended to be anchored to the subject's periurethral fascia. In some embodiments of the implant 100 the width of the distal portion 1200 is at least as great as the distance between a human's left and right periurethral fascia. Such embodiments of the distal portion 1200 can then be anchored to the left and right periurethral fascia of the subject when implanted. Excess material on the distal portion 1200 may be trimmed if not necessary for anchoring or covering the urethra. For typical human subjects, suitable widths of the distal portion 1200 may be, for example, at least about 14 mm, at least about 18 mm, and at least about 20 mm.
[0048] The proximal portion 1100 is intended to be anchored to pelvic structures. Accordingly, some embodiments of the proximal portion 1100 have a width greater than about the minimum distance between the right pelvic fascia and the left pelvic fascia of an adult human female. There is no upper bound to the width of the proximal portion 1100 , as the proximal portion 1100 may be trimmed after manufacture to fit the individual subject. The proximal portion 1100 may in some cases be anchored to structures outside of the pelvic fascia, such as the pelvic periosteum. Some anchoring means may allow the proximal portion 1100 to be very slightly narrower than minimum distance between the right pelvic fascia and the left pelvic fascia, for example if the anchoring means cover the intervening distance between the pelvic fascia and the implant 100 .
[0049] Some embodiments of the proximal portion 1100 are dimensioned to allow specific structures that are parts of the pelvic fascia to be used as anchor points. For example, in some embodiments of the implant 100 the width of the proximal portion 1100 is greater than about the minimum distance between the right pectineal ligament and the left pectineal ligament of the subject. In another example, the width of the proximal portion 1100 is greater than about the minimum distance between the right obturator fascia and the left obturator fascia of the subject. In yet another example, the width of the proximal portion 1100 is greater than about the minimum distance between the right obturator fascia and the left obturator fascia of an adult human female and less than the maximum distance between the right ilium and the left ilium of an adult human female.
[0050] The width of the proximal portion 1100 may also be defined in accordance with the absolute (as opposed to relative) dimensions of a typical adult human female. In some embodiments of the implant 100 the width of the proximal portion 1100 is at least about 7 cm or at least about 9 cm.
[0051] The implant 100 may further comprise an expandable member 1300 configured to apply pressure to the urethra when the implant 100 is in place. The expandable member 1300 is fastened to the distal portion 1200 , and has a width adequate to achieve compression of the urethra that partially or wholly arrests the flow of urine. The expandable member 1300 has an expanded state and an unexpanded state. In some embodiments of the expandable member 1300 , the expandable member 1300 is configured to primarily expand in a single direction. In some embodiments of the expandable member 1300 the expanded state protrudes in the posterior direction toward the urethra when in place in the subject. The expanded state may occupy a greater volume than the unexpanded state, but embodiments of the expandable member 1300 are contemplated in which the expanded state protrudes in the posterior direction toward the urethra when in place but does not increase in volume.
[0052] Some embodiments of the expandable member 1300 have a width greater than the width of a subject's urethra. This may relate to any subject as described above in the general discussion of the dimensions of bodily structures.
[0053] Some embodiments of the expandable member 1300 are inflatable (an inflatable member). The inflatable member is inflated with a fluid. The fluid may be introduced or removed through a conduit. In some embodiments of the implant 100 the fluid is exchanged between the inflatable member and a reservoir. When the member is inflated (for example to arrest a flow of urine) at least a portion of the fluid is transferred from the reservoir to the inflatable member. When the member is deflated (for example to allow the subject to urinate) at least a portion of the fluid is transferred from the member to the reservoir. Any suitable fluid may be used as known in the art. Examples include water, saline solution, and air. Water and saline have the advantages of being inexpensive, biocompatible in case of a leak, and incompressible. Air has the advantage of not requiring a reservoir (although one may be used).
[0054] Other versions of the expandable member 1300 do not operate by inflation. Some embodiments of the expandable member 1300 comprise a shaped memory material that compresses the urethra upon recovery of its shape after deformation. Other embodiments of the expandable member 1300 comprise a magnetic solenoid. Additional means for compressing the urethra are known in the art.
[0055] The dimensions of the expandable member 1300 will provide the desired compression of the urethra when expanded and still be sufficiently thin to be implanted when unexpanded. For example, in some embodiments of the implant 100 the thickness of the expandable member 1300 is no more than about 2 mm in the unexpanded state, and is about 8-10 mm in the expanded state. The expandable member 1300 may be substantially planar when unexpanded so as to fit in against the urethra without exerting pressure in the unexpanded state.
[0056] In embodiments of the expandable member 1300 that are inflatable, the expandable member 1300 may comprise a hollow balloon portion 1310 . In further embodiments, the expandable member 1300 comprises a hollow balloon portion 1310 and a resilient anchor portion 1320 at the periphery of the balloon portion 1310 . The anchor portion 1320 has sufficient tensile strength to be connected to the distal portion 1200 (such as by adhesives or fasteners) without failing.
[0057] Some embodiments of the expandable member 1300 are configured to primarily expand in the posterior direction. The expandable member 1300 will be constructed of a material that allows it to protrude in the posterior direction into the urethra in its expanded state. Some embodiments of the expandable member 1300 are constructed of material that is flexible, elastic, or both. In a specific embodiment of the implant 100 the expandable member 1300 is constructed of a flexible or elastic material, and the distal member is constructed of non-elastic material. This allows the distal member to act as a rigid backing for the expandable member 1300 when anchored in place, such that the expandable member 1300 will expand toward the urethra without pushing the distal portion 1200 outward in the anterior direction at the same time. Accordingly in some embodiments of the implant 100 the expandable member 1300 is confined by the distal portion 1200 against expansion in the anterior direction, distal direction, or proximal direction.
[0058] The expandable member 1300 need not surround or encircle the urethra in order to function properly. Some embodiments of the expandable member 1300 contact the urethra only on the anterior surface. Other embodiments of the expandable member 1300 contact the urethra over less than its entire circumference. Further embodiments of the expandable member 1300 contact the urethra over less than 180° of its circumference.
[0059] Alternatively, pressure may be exerted on the urethra by a bulge on the distal portion with a width greater than the width of an adult human urethra. The dimensions of the bulge may be any that are disclosed above as suitable for the expandable member. The bulge generally does not change in thickness (unlike the expandable member), but has a generally fixed thickness that does not completely arrest the flow of urine at all times. The bulge is dimensioned to compress the urethra to an extent to allow a patient with weakened pelvic floor muscles to control the flow of urine, whereas without the additional compression provided by the bulge this would not be possible. The bulge may be any embodiment of the expandable member above, given that in such an embodiment the expandable member is expanded or inflated a certain amount, but thereafter remains of static thickness in the patient.
[0060] Some embodiments of the implant 100 comprise a loop of transvaginal graft 1600 fastened to the distal portion 1200 of the implant 100 . The loop of transvaginal graft can function to provide opposing resistance on the posterior surface of the urethra for those patients in need of such additional opposing resistance. The graft can be made from any suitable graft material known in the art. Some embodiments of the graft material are made from autologous graft material, allograft material, and xenograft material. Specific examples of autologous graft material include material from the rectus fascia, the dermis, and the fascia lata. The loop of transvaginal graft 1600 will be dimensioned to be capable of encircling the urethra, and therefore will have a length at least equal to the circumference of a patient's urethra. In a specific embodiment the loop of transvaginal graft 1600 is approximately 2 cm wide by approximately 1.5-2.0 cm long. In embodiments of the implant 100 comprising the loop of transvaginal graft 1600 , the distal portion 1200 may comprise one or more loop anchors 1210 , for example grommets.
C. Methods
[0061] Method are provided related to the purposes of the implant 100 above, such as treating or preventing urinary incontinence, supporting the proximal urethra, supporting the bladder neck, and emplacing a surgical implant against the anterior urethra of a subject.
[0062] A general embodiment of the method comprises anchoring any of the implants 100 described above to a proximal structure and the periurethral fascia of a subject such that the distal portion 1200 contacts the anterior surface of the urethra. In some embodiments of the method the expandable member contacts the urethra of the subject.
[0063] Another general embodiment of the method is a method of emplacing a surgical implant against the anterior urethra of a subject, the method comprising: anchoring the proximal portion of an implant to a proximal structure of the subject so that the implant is positioned between the bladder and the pubic bone and in contact with the anterior surface of the bladder; and anchoring the distal portion of the implant to the right and left periurethral fascia of the subject; so that the distal portion of the implant contacts the anterior surface of at least one structure selected from: the bladder neck and the proximal urethra.
[0064] A further general embodiment of the method is a method of supporting the proximal urethra or bladder neck of a subject, comprising fixating one or both of the proximal urethra and the bladder neck from the anterior side. Specific embodiments may comprise fixating the proximal urethra from the anterior side. This general embodiment may further comprise contacting the proximal urethra or bladder neck from the anterior side with a substantially rigid implant anchored to a proximal structure.
[0065] Any of the above methods may comprise reversibly compressing the one or both of the proximal urethra and bladder neck from the anterior side to treat incontinence. Such compression may be achieved for example by contacting at least one of the proximal urethra and bladder neck with any expandable member as described above and expanding the expandable member.
[0066] The proximal structure to which the implant is anchored may be any that is described as suitable above. In certain embodiments the proximal structure may be selected from the group consisting of: the pelvic fascia, the obturator fascia, and the pectineal ligament. Some embodiments of the method comprise anchoring the distal portion to the public periosteum of the subject. This provides additional stability to the implant by anchoring its distal edge. Of course the implant must be dimensioned accordingly to allow the distal portion to be sufficiently close to the pubic periosteum for anchorage.
[0067] Anchoring may be achieved using any suitable anchoring means, such as soluble sutures, staples, and adhesives.
[0068] The method may comprise positioning the expandable member on the anterior surface of at least one of the proximal urethra and bladder neck. Thus positioned, the expandable member may be expanded to compress the proximal urethra and bladder neck to control incontinence.
[0069] Embodiments of any of the above methods may comprise inserting the implant through an incision in the lower abdomen of the subject.
[0070] The method may be performed openly or laparoscopically. One advantage of some embodiments of the anterior approach to emplacing the implant is that it may be performed robotically (as a form of laparoscopy). The alternative transvaginal approach is too complex to be automated using current robotic technology. The advantages of robotic surgery are numerous, including permitting the procedure to be performed telesurgically, reducing the risk of infection, and allowing the use of microsurgical techniques.
D. Prophetic Example
[0071] In a non-limiting prophetic example, an implant 100 constructed of Type I macroporous polypropylene mesh will be implanted into a subject to treat urinary incontinence. The implant 100 will comprise: a proximal portion 1100 at least 10 cm wide, about 1 mm thick, and about 25 mm long; a distal portion 1200 about 18 mm wide, about 25 mm long, and about 1 mm thick; and an expandable member 1300 fastened to the distal portion 1200 that is configured to apply pressure on only the anterior surface of the urethra when in place.
[0072] After appropriate general anesthesia, the patient will be placed in a low lithotomy position. A lower abdominal prep will be carried out as well as a full vaginal prep. A Foley catheter will be placed in the bladder.
[0073] A Pfannenstiel-style incision will be made and tissue will be dissected down to the level of the rectus fascia. Dissection will be carried out through the rectus fascia and into the space of Retzius. Stationary retractors will be used for exposure.
[0074] The fibrofatty tissue will be bluntly dissected off the undersurface of the pubic bone. This will provide exposure to the bladder, urethra, and the pelvic fascia.
[0075] Two fingers will be placed in the vaginal area in order to lift up on the anterior vaginal wall. The other hand will retract on the bladder neck with the balloon of the Foley as a guide. The proximal urethra and bladder neck will be exposed.
[0076] Blunt dissection will be carried out to the pelvic sidewall in order to well visualize the endopelvic fascia as well as the arcus tendineus and other fascia structures of the pelvis.
[0077] The aforementioned non-absorbable implant 100 with expandable body will be placed into the pelvis. This will be positioned with the distal segment of the implant 100 overlaying the proximal urethra. Some of the distal segment may overlay a portion of the bladder neck. The proximal segment of the implant 100 will be positioned over the anterior bladder and bladder neck area. The more lateral portions of the proximal segment will be laid over the pelvic sidewall fascia. Excess mesh from the lateral portions will be excised if longer than the width of the pelvic fascia. The non-absorbable material at any location will be trimmed (excluding the expandable body area) if necessary to custom fit to the patient's pelvic anatomy.
[0078] Interrupted Vicryl sutures will be used to fixate the mesh at different locations in the pelvis. The more distal segment will be fixated to the periurethral fascia as it enters under the pubic bone. More fixation sutures will be placed on the lateral borders of the distal segment as the fascia continues to the bladder neck area.
[0079] Lateral fixation of the proximal segment will be carried out with interrupted sutures. Fixation points include the endopelvic fascia, arcus tendineus and in some situations depending on the patient's anatomy, the obturator internus or the pectineal ligament.
[0080] The sutures will be placed on the more proximal segment to allow it to lay flat on the endopelvic fascia as it approaches the arcus tendineus. The implant 100 will not be placed under tension.
[0081] After the implant 100 appears to be in good position, the tubing 1330 from the expandable body will be connected to a syringe and inflated. This will allow visualization to verify that it stays in place while the expandable body provides compression on the proximal urethra in a posterior direction.
[0082] Cystourethroscopy will be carried out to visualize complete closure of the proximal urethra. After this confirmation, the expandable body will be deflated.
[0083] A reservoir with fluid will be placed into the left lower pelvis. A trocar will be placed posterior to the left side of the pubic bone and punctured out through the left genital area just lateral to the left labia. This will be affixed to another more blunt trocar with a hook that will be pulled into the pelvis. This trocar with a hook is attached to the ends of the tubing 1330 from the expandable body and the reservoir. Both tubings will be pulled out of the pelvis lateral to the left labia.
[0084] The abdomen will be irrigated and the rectus fascia and skin will be closed.
[0085] Attention will be placed on the paravaginal area at the location of the tubing 1330 and the puncture site. An incision will be carried out at that location superiorly and inferiorly. A pocket will be created within the labia in order to place the pump. Excess tubing will be cut from the reservoir and the expandable body and attached to the pump.
[0086] The pump will be placed in this pouch, the area will be copiously irrigated, and the skin will be closed. The Foley catheter can be removed and the expandable body shall remain in the non-inflated position during the perioperative period.
E. Conclusions
[0087] It is to be understood that any given elements of the disclosed embodiments of the invention may be embodied in a single structure, a single step, a single substance, or the like. Similarly, a given element of the disclosed embodiment may be embodied in multiple structures, steps, substances, or the like.
[0088] The foregoing description illustrates and describes the processes, machines, manufactures, compositions of matter, and other teachings of the present disclosure. Additionally, the disclosure shows and describes only certain embodiments of the processes, machines, manufactures, compositions of matter, and other teachings disclosed, but, as mentioned above, it is to be understood that the teachings of the present disclosure are capable of use in various other combinations, modifications, and environments and are capable of changes or modifications within the scope of the teachings as expressed herein, commensurate with the skill and/or knowledge of a person having ordinary skill in the relevant art. The embodiments described hereinabove are further intended to explain certain best modes known of practicing the processes, machines, manufactures, compositions of matter, and other teachings of the present disclosure and to enable others skilled in the art to utilize the teachings of the present disclosure in such, or other, embodiments and with the various modifications required by the particular applications or uses. Accordingly, the processes, machines, manufactures, compositions of matter, and other teachings of the present disclosure are not intended to limit the exact embodiments and examples disclosed herein. Any section headings herein are provided only for consistency with the suggestions of 37 C.F.R. §1.77 or otherwise to provide organizational queues. These headings shall not limit or characterize the invention(s) set forth herein.
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An implant is provided for maintaining the position of pelvic organs, such as components of the urinary tract. The implant contacts the anterior surface of the urethra and is anchored to the pelvic fascia and the periurethral fascia. A method of anchoring the pelvic organs is also provided, involving inserting the implant via an anterior approach, avoiding complications and side effects that result when implants are inserted through the wall of the vagina.
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FIELD OF THE INVENTION
The invention relates to a tape composition and the use of the tape in a method for substantially reducing or controlling planar shrinkage and reducing distortion of ceramic bodies during firing.
BACKGROUND OF THE INVENTION
An interconnect circuit board is a physical realization of electronic circuits or subsystems made from a number of extremely small circuit elements that are electrically and mechanically interconnected. It is frequently desirable to combine these diverse type electronic components in an arrangement so that they can be physically isolated and mounted adjacent to one another in a single compact package and electrically connected to each other and/or to common connections extending from the package.
Complex electronic circuits generally require that the circuit be constructed of several layers of conductors separated by insulating dielectric layers. The conductive layers are interconnected between levels by electrically conductive pathways, called vias, through a dielectric layer. Such a multilayer structure allows a circuit to be more compact.
The use of a ceramic green tape to make low temperature co-fired ceramic (LTCC) multilayer circuits was disclosed in U.S. Pat. No. 4,654,095 to Steinberg. The co-fired, free sintering process offered many advantages over previous technologies. However, shrinkage during the firing process was difficult to control when larger circuits were needed. A trend toward finer via diameters, pitch and lines and spaces continues to push the limit of free sintering LTCC technology.
An improved co-fired LTCC process was developed and is disclosed in U.S. Pat. No. 5,085,720 to Mikeska. The process placed a ceramic-based release tape layer on the external surfaces of a green LTCC laminate assembly. The tape controlled shrinkage during the firing process. The process is a great improvement regarding the reproducibility of shrinkage during firing. It allowed the fired dimension of circuit features to be predictable.
U.S. Pat. No. 6,139,666 to Fasano et al. discloses a process where the edges of a multilayer ceramic are chamfered with a specific angle to correct edge distortion, due to imperfect shrinkage control exerted by an externally applied release tape during firing.
Another process for control of registration in an LTCC structure was disclosed in U.S. Pat. No. 6,205,032 to Shepherd. The process fires a core portion of a LTCC circuit incurring normal shrinkage and shrinkage variation of an unconstrained circuit. Subsequent layers are made to match the features of the pre-fired core, which then is used to constrain the sintering of the green layers laminated to the rigid pre-fired core. The planar shrinkage is controlled to the extent of 0.8-1.2%. The technique is limited to a few layers, before registration becomes unacceptable.
As disclosed in U.S. Pat. No. 5,085,720 during the firing step to form a refractory ceramic article, a constraining tape layer or layers on the surface of the article acts to pin and restrain possible shrinkage of the article in the x and y directions due to the refractory and rigid properties of the constraining tape. The un-sintered material in the constraining tape is then removed by brushing or other cleaning procedure. The constrained material may be composed of one or more layers of green tape, which sinter and densify to form a desired ceramic LTCC body.
In the production of LTCC circuits, the use of a sacrificial constraining tape means that the user must purchase a tape material that does not end up in the final product and that it also causes a cleanliness issue (un-sintered powder removal from fired part surface) in the furnace area. Furthermore, the top and bottom surface circuitry may not be patterned and co-fired between the LTCC body and the constraining tape. In the present invention, the constraining tape is fundamentally different. It is found layered on or within the LTCC structure and becomes part of the final LTCC body.
SUMMARY OF THE INVENTION
The invention is directed to a method for reducing x,y shrinkage during firing of a green assembly comprising at least one layer of glass-containing non-sacrificial constraining tape and at least one layer of glass-containing primary tape wherein the constraining tape and the primary tape are laminated to form an assembly, wherein the tape layers of the assembly upon thermal processing exhibit an interactive suppression of x,y shrinkage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of an assembly formed by the method of the present invention.
FIGS. 2-11 are Thermo-Mechanical Analysis Data (TMA) plots showing test results of the Examples.
DETAILED DESCRIPTION OF THE INVENTION
The current invention extends the teachings of constrained sintering to the use of a non-fugitive, non-removable or non-release constraining tape that is inserted in or on an assembly that comprises predominantly a layer or layers of a primary tape that defines the properties required of the LTCC assembly, so that zero or almost zero shrinkage occurs in the x,y direction after the assembly is fired (i.e., shrinkage is enhanced in the z-direction). In addition, the production of blind or through cavities in or on an assembly by conventional methods has been an ongoing problem. The current invention solves such problems because the layers can conform to such cavities.
In one embodiment of this invention as shown in FIG. 1, a physical constraining layer ( 102 ) is formulated to be a functional component of the LTCC final assembly ( 100 ). The properties of the constraining layer are to provide a rigid physical form to restrain the x and y shrinkage of the primary tapes ( 101 ); however, its purpose is extended to impart functional properties to the final LTCC assembly. There is no sacrificial or material lost to the constraining process. The constraining tape of this invention, in general, precedes the sintering of the primary tape layers. Although the constraining tape may be placed between layers of the primary tape, it is not essential to be in the exact center of a the assembly prior to firing, so long as a structural symmetry between the primary and constraining tape exists. Preferably, the number of primary to constraining tape layers is in the range of 10 to 1. Also, preferably, the overall thickness of the primary to the constraining tape layer is in the range of 30:1 to 12:5. This symmetry should be around a horizontal plane that bisects the z-axis at the center point. This limitation is currently dictated by the choice of materials in the primary tape. The constraining tape may also be placed on the outer surface of primary tape materials. The constraining tape is further characterized as composed of a filler ceramic material such as Al 2 O 3 , ZrO 2 , ZrSiO 4 , etc., with a crystallizable or filler reactable glass composition so that its flow, densification and rigidification during firing proceed the remaining layers of primary tape. Although a constraining or primary tape normally may consist of a glass and filler, it may be designed by skilled artisans to utilize more than one glass or more than one filler. The physical act of restricting the x,y shrinkage of the constraining tape by the primary tape during thermal processing is quite similar to the externally applied constraining layers of a conventional primary tape assembly. It is to be noted, however, that although the terms of “primary tape” and “constraining tape” are used in this invention, the “primary tape” constrains the “constraining tape” during its lower temperature sintering/crystallization process; whereas the already sintered “constraining tape” constrains the “primary tape” during its higher temperature firing. The requirements for suitable materials to serve as a non-sacrificed constraining tape are however different. These material requirements are considered below.
A conventional LTCC primary tape typically processes at temperatures near 850° C. When a conventional release constraining tape is used, it must not sinter or become part of the final LTCC body to function properly. Contrary to that, a constraining tape of the present invention contains glasses that flow, densify, and become rigid at temperatures significantly below 850° C., which is a standard process temperature.
The constraining tape becomes part of the final LTCC body. This significantly increases the performance requirements for the constraining tape material. The electrical properties (i.e., dielectric constant) of the constraining tape may also be adjusted with a choice of materials that make up the tape. This makes possible the use of more than one chemical type of primary tape to locally control the dielectric and other electrical properties of a portion of a LTCC circuit.
The primary tape is generally the majority tape in a LTCC assembly and the resultant fired assembly derives its mechanical and electrical characteristics from it. In most situations the constraining tape has a minority presence in the structure. It can be used effectively to locally modify aspects of the dielectric and other electrical performance of the assembly, but its biggest influence is to control the physical structure by constraining its x,y shrinkage substantially to zero.
One embodiment involves two layers of primary tape located on opposing sides of a single layer of constraining tape. During the heating of the assembly, the glass in the constraining tape attains its transition temperature (the temperature at which the glass softens and flows) earlier than the glass of the primary tape and it flows sufficiently to coat the surface particles of the adjacent layers of the primary tape. Since the crystallization temperature of this glass is close to its transition temperature, crystallization occurs very soon after. This has the result of stiffening the glass and significantly raising its composite viscosity or elevating its re-melting temperature beyond the peak firing temperature of 825 to 875° C. of the first co-firing and/or subsequent post-firing process.
Although crystallization is a preferred method to rigidify tape after the densification and flow period of a glass filled tape, phase immiscibility using glass or glass-filler mixtures to effectively rigidify the tape is also a possible method. This process from sintering onset to rigidification can be measured for glass and filler combinations by the use of TMA, Thermo-mechanical analysis. For example, preferably the glass in the primary tape exhibits an onset of dimensional change as measured in TMA of about 700° C. or higher. Preferably the glass in the constraining tape exhibits an onset of dimensional change as measured in TMA of about 75° C. or more preferably 100 to 150° C. lower than the primary tape.
The constraining influence of the primary tape ensures that x,y shrinkage in the constraining tape is very small, if not zero. Subsequent increases in temperature cause the constraining tape to sinter fully and its glass to complete its crystallization. Since a suitable glass will, typically, develop in excess of 50 volume % crystalline phases, the constraining tape body becomes rigid when dominated by the volumetric accumulation of crystalline content of filler and in situ formation of crystal from the glass. Then, when the transition temperature of the primary tape glass is achieved and flow occurs, it is kept physically in place by its previous interaction with the constraining tape. Thus, the already-sintered constraining tape layers becomes the constraining force and the primary tape is constrained while sintering to shrink only in the z-direction. Once the assembly is fully sintered and has cooled down, the assembly will be seen to possess the same dimensions in the x,y direction as the original “green” or unfired assembly. The layers of the now chemically-reacted inorganic components of the two or more individual tapes used in the assembly are interleaved in various configurations. The only still observable boundaries being those where tapes of different chemistries were placed adjacent to each other.
Such an innovation offers the advantages of facilitating cofireable top and bottom conductors and also relieves the practical restrictions that externally-constrained sintered structures experience as the layer count is increased and the constraining influence of the external release tape is felt less and less. Furthermore, there is no need to remove the sacrificial constraining tape by mechanical and/or chemical means, hence the saving of equipment expenditure, labor, and the possible environmental contamination. In addition, the use of the constraining tape allows the formation of exactly dimensioned, non-shrink cavities in a tape structure. Both blind and through cavities can be produced by this constrained sintering technique.
In order to meet the performance requirements of LTCC circuit manufacturers, additional material performance factors must be considered beyond the simple process of constraining the x,y shrinkage in the green tape assembly when thermally processed. The coefficient of thermal expansion of both the constraining tape and the primary tape must be sufficiently close in magnitude to provide for the production of 6″×6″ or larger ceramic boards consisting of many layers of laminated green tape materials. In attention to this could result in stress induced cracking in the fired ceramic LTCC body during the temperature descending portion of the furnace firing or thereafter.
Another design factor is created because the constraining tape dielectric must be thermally processed to a rigid body prior to the primary tape to provide proper system x,y constraint. This means that the glass-filler material in the constraining tape should be designed to attain a lower composite viscosity to the primary tape, but at a temperature of approximately 50-150° C. lower in temperature and preferably in the range of 80-150° C. It should be noted that the above assessment was based on a belt furnace firing profile at an ascending rate of 6-8° C. per minute between 450° C. and 800° C. Such a profile is commonly used to achieve high throughput in mass production of LTCC circuit substrates. However, a smaller temperature difference (e.g. <50° C.) can also be effective if the firing profile in a multiple zone belt or box furnace provides a plateau to facilitate the full densification, and/or crystallization, and rigidification of the constraining tape. It should also provide sufficient compatibility between constraining and primary tapes during the densification to maintain the strength and bonding at the respective tape interfaces. This compatibility can be influenced by tape formulation, physical characteristics of the constituents and changes in thermal processing conditions. The electrical properties of the constraining tape material must also meet performance requirements for high frequency circuit applications. Tape components and formulations follow.
Specific examples of glasses that may be used in the primary or constraining tape are listed in Table 1. Preferred glass compositions found in the constraining tape comprise the following oxide constituents in the compositional range of: B 2 O 3 6-13, BaO 20-22, Li 2 O 0.5-1.5, P 2 O 5 3.5-4.5, TiO 2 25-33, Cs 2 O 1-6.5, Nd 2 O 3 29-32 in weight %. The more preferred composition of glass being: B 2 O 3 11.84, BaO 21.12, Li 2 O 1.31, P 2 O 5 4.14, TiO 2 25.44, Cs 2 O 6.16, Nd 2 O 3 29.99 in weight %. Another preferred glass comprises the following oxide constituents in the compositional range of: SiO 2 12-14, ZrO 2 3-6, B 2 O 3 20-27, BaO 12-15, MgO 33-36, Li 2 O 1-3, P 2 O 5 3-8, Cs 2 O 0-2 in weight %. The preferred composition of glass being: SiO 2 13.77, ZrO 2 4.70, B 2 O 3 26.10, BaO 14.05, MgO 35.09, Li 2 O 1.95, P 2 O 5 4.34 in weight %.
Preferred glasses for use in the primary tape comprise the following oxide constituents in the compositional range of: SiO 2 52-54, Al 2 O 3 12.5-14.5, B 2 O 3 8-9, CaO 16-18, MgO 0.5-5, Na 2 O 1.7-2.5, Li 2 O 0.2-0.3, SrO 0-4, K 2 O 1-2 in weight %. The more preferred composition of glass being: SiO 2 53.50, Al 2 O 3 13.00, B 2 O 3 8.50, CaO 17.0, MgO 1.00 Na 2 O 2.25, Li 2 O 0.25, SrO 3.00, K 2 O 1.50 in weight %.
In the primary or constraining tape the D 50 (median particle size) of frit is preferably in the range of, but not limited to, 0.1 to 5.0 mils and more preferably 0.3 to 3.0 mils.
The glasses described herein are produced by conventional glass making techniques. The glasses were prepared in 500-1000 gram quantities. Typically, the ingredients are weighed then mixed in the desired proportions and heated in a bottom-loading furnace to form a melt in platinum alloy crucibles. As well known in the art, heating is conducted to a peak temperature (1450-1600° C.) and for a time such that the melt becomes entirely liquid and homogeneous. The glass melts were then quenched by counter rotating stainless steel roller to form a 10-20 mil thick platelet of glass. The resulting glass platelet was then milled to form a powder with its 50% volume distribution set between 1-5 microns. The glass powders were then formulated with filler and organic medium to cast tapes as detailed in the Examples section. The glass compositions shown in Table 1 represent a broad variety of glass chemistry (high amounts of glass former to low amounts of glass former). The glass former oxides are typically small size ions with high chemical coordination numbers such as SiO 2 , B 2 O 3 , and P 2 O 5 . The remaining oxides represented in the table are considered glass modifiers and intermediates.
TABLE 1
(wt. %)
Glass #
SiO 2
Al 2 O 3
PbO
ZrO 2
B 2 O 3
CaO
BaO
MgO
Na 2 O
Li 2 O
P 2 O 5
TiO 2
K 2 O
Cs 2 O
Nd 2 O 3
SrO
1
6.08
23.12
5.40
34.25
32.05
2
13.77
4.70
26.10
14.05
35.09
1.95
4.34
3
55.00
14.00
9.00
17.50
4.50
4
11.91
21.24
0.97
4.16
26.95
4.59
30.16
5
56.50
9.10
17.20
4.50
8.00
0.60
2.40
1.70
6
11.84
21.12
1.31
4.14
25.44
6.16
29.99
7
52.00
14.00
8.50
17.50
4.75
2.00
0.25
1.00
8
6.27
22.79
0.93
4.64
33.76
31.60
9
9.55
21.73
0.92
4.23
32.20
1.24
30.13
10
10.19
21.19
0.97
4.15
28.83
4.58
30.08
11
13.67
5.03
25.92
13.95
34.85
1.94
4.64
12
12.83
4.65
21.72
13.09
34.09
1.96
11.65
13
13.80
4.99
25.86
13.34
33.60
2.09
4.35
1.87
14
52.00
14.00
9.00
17.50
5.00
1.75
0.25
0.50
15
53.5
13.00
8.50
17.00
1.00
2.25
0.25
1.50
3.00
16
13.77
4.70
22.60
14.05
35.09
1.95
7.84
17
54.00
12.86
8.41
16.82
0.99
2.23
0.25
1.48
2.96
Ceramic filler such as Al 2 O 3 , ZrO 2 , TiO 2 , BaTiO 3 or mixtures thereof may be added to the castable dielectric composition in an amount of 0-50 wt. % based on solids. Depending on the type of filler, different crystalline phases are expected to form after firing. The filler can control dielectric constant and loss over the frequency range. For example, the addition of BaTiO 3 can increase the dielectric constant significantly.
Al 2 O 3 is the preferred ceramic filler since it reacts with the glass to form an Al-containing crystalline phase. Al 2 O 3 is very effective in providing high mechanical strength and inertness against detrimental chemical reactions. Another function of the ceramic filler is rheological control of the entire system during firing. The ceramic particles limit flow of the glass by acting as a physical barrier. They also inhibit sintering of the glass and thus facilitate better burnout of the organics. Other fillers, α-quartz, CaZrO 3 , mullite, cordierite, forsterite, zircon, zirconia, BaTiO 3 , CaTiO 3 , MgTiO 3 , SiO 2 , amorphous silica or mixtures thereof may be used to modify tape performance and characteristics. It is preferred that the filler has at least a bimodal particle size distribution with D50 of the larger size filler in the range of 1.5 and 2 microns and the D50 of the smaller size filler in the range of 0.3 and 0.8 microns.
In the formulation of tape compositions, the amount of glass relative to the amount of ceramic material is important. A filler range of 20-40% by weight is considered desirable in that the sufficient densification is achieved. If the filler concentration exceeds 50% by wt., the fired structure is not sufficiently densified and is too porous. Within the desirable glass/filler ratio, it will be apparent that, during firing, the liquid glass phase will become saturated with filler material.
For the purpose of obtaining higher densification of the composition upon firing, it is important that the inorganic solids have small particle sizes. In particular, substantially all of the particles should not exceed 15 μm and preferably not exceed 10 μm. Subject to these maximum size limitations, it is preferred that at least 50% of the particles, both glass and ceramic filler, be greater than 1 μm and less than 6 μm.
The organic medium in which the glass and ceramic inorganic solids are dispersed is comprised of a polymeric binder which is dissolved in a volatile organic solvent and, optionally, other dissolved materials such as plasticizers, release agents, dispersing agents, stripping agents, antifoaming agents, stabilizing agents and wetting agents.
To obtain better binding efficiency, it is preferred to use at least 5% wt. polymer binder for 90% wt. solids, which includes glass and ceramic filler, based on total composition. However, it is more preferred to use no more than 30% wt. polymer binder and other low volatility modifiers such as plasticizer and a minimum of 70% inorganic solids. Within these limits, it is desirable to use the least possible amount of binder and other low volatility organic modifiers, in order to reduce the amount of organics which must be removed by pyrolysis, and to obtain better particle packing which facilitates full densification upon firing.
In the past, various polymeric materials have been employed as the binder for green tapes, e.g., poly(vinyl butyral), poly(vinyl acetate), poly(vinyl alcohol), cellulosic polymers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, methylhydroxyethyl cellulose, atactic polypropylene, polyethylene, silicon polymers such as poly(methyl siloxane), poly(methylphenyl siloxane), polystyrene, butadiene/styrene copolymer, polystyrene, poly(vinyl pyrollidone), polyamides, high molecular weight polyethers, copolymers of ethylene oxide and propylene oxide, polyacrylamides, and various acrylic polymers such as sodium polyacrylate, poly(lower alkyl acrylates), poly(lower alkyl methacrylates) and various copolymers and multipolymers of lower alkyl acrylates and methacrylates. Copolymers of ethyl methacrylate and methyl acrylate and terpolymers of ethyl acrylate, methyl methacrylate and methacrylic acid have been previously used as binders for slip casting materials.
U.S. Pat. No. 4,536,535 to Usala, issued Aug. 20, 1985, has disclosed an organic binder which is a mixture of compatible multipolymers of 0-100% wt. C18 alkyl methacrylate, 100-0% wt. C 18 alkyl acrylate and 0-5% wt. ethylenically unsaturated carboxylic acid of amine. Because the above polymers can be used in minimum quantity with a maximum quantity of dielectric solids, they are preferably selected to produce the dielectric compositions of this invention. For this reason, the disclosure of the above-referred Usala application is incorporated by reference herein.
Frequently, the polymeric binder will also contain a small amount, relative to the binder polymer, of a plasticizer that serves to lower the glass transition temperature (Tg) of the binder polymer. The choice of plasticizers, of course, is determined primarily by the polymer that needs to be modified. Among the plasticizers which have been used in various binder systems are diethyl phthalate, dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate, alkyl phosphates, polyalkylene glycols, glycerol, poly(ethylene oxides), hydroxyethylated alkyl phenol, dialkyldithiophosphonate and poly(isobutylene). Of these, butyl benzyl phthalate is most frequently used in acrylic polymer systems because it can be used effectively in relatively small concentrations.
The solvent component of the casting solution is chosen so as to obtain complete dissolution of the polymer and sufficiently high volatility to enable the solvent to be evaporated from the dispersion by the application of relatively low levels of heat at atmospheric pressure. In addition, the solvent must boil well below the boiling point or the decomposition temperature of any other additives contained in the organic medium. Thus, solvents having atmospheric boiling points below 150° C. are used most frequently. Such solvents include acetone, xylene, methanol, ethanol, isopropanol, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrachloroethylene, amyl acetate, 2,2,4-triethyl pentanediol-1,3-monoisobutyrate, toluene, methylene chloride and fluorocarbons. Individual solvents mentioned above may not completely dissolve the binder polymers. Yet, when blended with other solvent(s), they function satisfactorily. This is well within the skill of those in the art. A particularly preferred solvent is ethyl acetate since it avoids the use of environmentally hazardous chlorocarbons.
In addition to the solvent and polymer, a plasticizer is used to prevent tape cracking and provide wider latitude of as-coated tape handling ability such as blanking, printing, and lamination. A preferred plasticizer is BENZOFLEX® 400 manufactured by Rohm and Haas Co., which is a polypropylene glycol dibenzoate.
Application
A green tape for use as a constraining tape or a primary tape is formed by casting a thin layer of a slurry dispersion of the glass, ceramic filler, polymeric binder and solvent(s) as described above onto a flexible substrate, heating the cast layer to remove the volatile solvent. It is preferred that the primary tape not exceed 20 mils in thickness and preferably 1 to 10 mils. It is preferred that the constraining tape be 1 to 10 mils and preferably 1 to 3 mils in thickness. The tape is then blanked into sheets or collected in a roll form. The green tape is typically used as a dielectric or insulating material for multilayer electronic circuits. A sheet of green tape is blanked with registration holes in each corner to a size somewhat larger than the actual dimensions of the circuit. To connect various layers of the multilayer circuit, via holes are formed in the green tape. This is typically done by mechanical punching. However, a sharply focused laser can be used to volatilize and form via holes in the green tape. Typical via hole sizes range from 0.004″ to 0.25″. The interconnections between layers are formed by filling the via holes with a thick film conductive ink. This ink is usually applied by standard screen printing techniques. Each layer of circuitry is completed by screen printing conductor tracks. Also, resistor inks or high dielectric constant inks can be printed on selected layer(s) to form resistive or capacitive circuit elements. Furthermore, specially formulated high dielectric constant green tapes similar to those used in the multilayer capacitor industry can be incorporated as part of the multilayer circuitry.
After each layer of the circuit is completed, the individual layers are collated and laminated. A confined uniaxial or isostatic pressing die is used to insure precise alignment between layers. The laminate assemblies are trimmed with a hot stage cutter. Firing is carried out in a standard thick film conveyor belt furnace or in a box furnace with a programmed heating cycle. This method will, also, allow top and/or bottom conductors to be co-fired as part of the constrained sintered structure without the need for using a conventional release tape as the top and bottom layer, and the removal, and cleaning of the release tape after firing.
As used herein, the term “firing” means heating the assembly in an oxidizing atmosphere such as air to a temperature, and for a time sufficient to volatilize (burn-out) all of the organic material in the layers of the assemblage to sinter any glass, metal or dielectric material in the layers and thus densify the entire assembly.
It will be recognized by those skilled in the art that in each of the laminating steps the layers must be accurate in registration so that the vias are properly connected to the appropriate conductive path of the adjacent functional layer.
The term “functional layer” refers to the printed green tape, which has conductive, resistive or capacitive functionality. Thus, as indicated above, a typical green tape layer may have printed thereon one or more resistor circuits and/or capacitors as well as conductive circuits.
EXAMPLES
Tape compositions used in the examples were prepared by ball milling the fine inorganic powders and binders in a volatile solvent or mixtures thereof. To optimize the lamination, the ability to pattern circuits, the tape burnout properties and the fired microstructure development, the following volume % formulation of slip was found to provide advantages. The formulation of typical slip compositions is also shown in weight percentage, as a practical reference. The inorganic phase is assumed to have a specific density of 4.5 g/cc for glass and 4.0 g/cc for alumina and the organic vehicle is assumed to have a specific density of 1.1 g/cc. The weight % composition changes accordingly when using glass and oxides other than alumina as the specific density maybe different than those assumed in this example.
Volume %
Weight %
Inorganic phase
41.9
73.8
Organic phase
58.1
26.2
The above volume and weight % slip composition may vary dependent on the desirable quantity of the organic solvent and/or solvent blend to obtain an effective slip milling and coating performance. More specifically, the composition for the slip must include sufficient solvent to lower the viscosity to less than 10,000 centipoise; typical viscosity ranges are 1,000 to 4,000 centipoise. An example of a slip composition is provided in Table 2. Depending on the chosen slip viscosity, higher viscosity slip prolongs the dispersion stability for a longer period of time (normally several weeks). A stable dispersion of tape constituents is usually preserved in the as-coated tape.
TABLE 2
Slip Composition
Component
Weight %
Acrylate and methacrylate polymers
4.6
Phthalate type plasticizers
1.1
Ethyl acetate/isopropyl alcohol mixed solvent
20.4
Glass powder
50.7
Alumina powder
23.2
If needed, a preferred inorganic pigment at weight % of 0.5 to 1.0 may be added to the above slip composition before the milling process.
The glasses for the Examples found herein were all melted in Pt/Rh crucibles at 1450-1600° C. for about 1 hour in an electrically heated furnace. Glasses were quenched by metal roller as a preliminary step and then subjected to particle size reduction by milling. The powders prepared for these tests were adjusted to a 5-7 micron mean size by milling prior to formulation as a slip. Since additional milling is utilized in the fabrication of slip, the final mean size is normally in the range of 1-3 microns.
Thermo-mechanical analysis (TMA) measurements are presented in many of the following examples. The measurements were preformed using a TMA 2940 accessory module to a TA Instruments Thermal Analysis System. The samples were prepared by punching the green tape assembly to a 0.535″ diameter with a thickness that varied with the specific sample. The samples were loaded with an actively controlled 5-gram load and heated at 10° C./min. to 850° C. A soak of 5 minute duration was used before completing the run. The data were corrected for offset from zero at 500° C. and plotted between 500° C. and 900° C.
Example 1
Primary Tape Composition #1 (Glass #1, Table 1)
(6.8 mils tape thickness)
Glass:
B 2 O 3
6.08
wt. %
BaO
23.12
P 2 O 5
4.5
TiO 2
34.25
Nd 2 O 3
32.05
Glass Density 4.72 g/cc Alumina Density 4.02 g/cc
Filler: Al 2 O 3 (D50 = 2.5 micron)
Filler content 36.0 vol %
Glass content: 64.0 vol %
Constraining Tape Composition #1 (Glass #2, Table 1)
Glass:
SiO 2
13.77
wt. %
ZrO 2
4.7
B 2 O 3
26.1
BaO
14.05
MgO
35.09
Li 2 O
1.95
P 2 O 5
4.34
Glass Density 3.06 g/cc Alumina Density 4.02 g/cc
Filler: Al 2 O 3 (D50 = 2.5 micron)
Filler content 33.7 vol %
The solids formulation of the primary and constraining tapes are shown as filler and glass content above. Three tape structures were made using these materials in construction as follows:
Test #1
Prim#1/Constraining#1/Prim#1
constraining thickness 2.5 mils,
total/constraining thickness ratio = 6.4
Test #2
Prim#1/2xConstraining#1/Prim#1
constraining thickness 5.0 mils,
total/constraining thickness ratio = 3.7
Test #3
Prim#1/3xConstraining#1/Prim#1
constraining thickness 7.5 mils,
total/constraining thickness ratio = 2.8
All samples were flat following belt furnace firing at 850° C., and they showed the following % x,y-shrinkage: Test #1 0.20%, Test #2 0.17%, and Test #3 0.05%.
The uniaxial thickness reduction or z-shrinkage of each tape is shown in the following Thermo-Mechanical Analysis Data (TMA) plot (FIG. 2) of the Primary #1 and Constraining #1 Tape materials. As can be seen from the plot, the onset of tape sintering is separated by about 75-85° C. The constraining tape can be seen to develop rigid property near 700° C. and the primary tape at this temperature is just beginning to sinter.
The influence of the constraining tape thickness is seen to relate in general to the x,y-shrinkage values.
Example 2
A Primary #2 Tape (5 mils thick) is paired with two different constraining tape compositions (Constraining #1 and Constraining #2) having identical total/constraining tape thickness ratio.
Primary Tape Composition #2 (Glass #3, Table 1)
Glass: Filler: Al 2 O 3 (D50 = 2.5 micron) Filler content 36.0 vol %
SiO 2
55.00
wt %
Al 2 O 3
14.00
B 2 O 3
9.00
CaO
17.50
MgO
4.50
Glass Density 2.52 g/cc Alumina Density 4.02 g/cc
Constraining Tape Composition #2 (Glass #4, Table 1)
Glass: Filler: Al 2 O 3 (D50 = 2.5 micron)
Filler content 33.7 vol %
B 2 O 3
11.91
wt. %
BaO
21.24
TiO2
26.95
Li 2 O
0.97
P 2 O 5
4.16
Cs 2 O
4.59
Nd 2 O 3
30.16
Glass Density 4.54 g/cc Alumina Density 4.02 g/cc
The following tape structures are compared in this example:
Test #4
2xPrim#2/Constraining#1/2xPrim#2
constraining thickness 2.5 mils,
total/constraining thickness ratio = 9.0
Test #5
2xPrim#2/3xConstraining#1/2xPrim#2
constraining thickness 7.5 mils,
total/constraining thickness ratio = 3.7
Test #6
2xPrim#2/Constraining#2/2xPrim#2
constraining thickness 2.5 mils,
total/constraining thickness ratio = 9.0
All samples were flat following belt furnace firing at 850° C. and they showed the following % x,y-shrinkage: Test #4 0.19%, Test #5 0.03%, and Test #6 0.17%.
As one can see in Tests #4 and #5, the role of the thickness of the constraining tape influences the degree of x,y-shrinkage control. A significant point is shown in Tests #4 and #6, which have different constraining tape glass compositions and yet exhibit similar shrinkage control under identical tape laminate construction.
The TMA properties of the Primary #2, Constraining #1 and Constraining #2 Tapes are shown in the FIG. 3 . As the plot of these three tapes illustrates, the Constraining Tape #2 has a somewhat higher temperature at which it attains rigidity than Constraining Tape #1. However since the Primary Tape #2 has a higher temperature for onset of sintering than the Primary #1 Tape, either constraining tape achieves good x,y-shrinkage control in composite structures. The Test #4 or #6 shows, respectively, a 125° C. or 150° C. separation in sintering onset. These data show that a more generalized trend is attained when specific characteristics of the paired tape materials are satisfied.
Example 3
This example uses the Constraining Tape #1 with another Primary Tape #3. Although it is most desirable for both primary and constraining tapes to exhibit at least partial crystallization during their respective firing as shown in Examples 1 and 2, it is not essential.
Primary Tape #3 (Glass #5. Table 1)
(Tape Thickness 4.5 mils)
Glass:
SiO 2
56.5
wt. %
Al 2 O 3
9.1
PbO
17.2
B 2 O 3
4.5
Primary Tape #3 (Glass #5. Table 1)
(Tape Thickness 4.5 mils)
Glass:
CaO
8
MgO
0.6
Na 2 O
2.4
K 2 O
1.7
Glass Density 2.80 g/cc Alumina Density 4.02 g/cc
Filler: Al 2 O 3 (D50 = 2.5 micron)
Filler content 36.0 vol %
The TMA plots for 3 tape samples are shown in FIG. 4 . The Constraining Tape #1 is plotted with Primary Tape #3 which has a lesser tendency to crystallize than the previous two examples. Additionally a sample made from composite tape layers of 2×Prim #3/Constraining #½× Prim #3 was measured. The x,y-shrinkage for this composite sample was measured to be 1.24% (constraining thickness 2.5 mils, total to constraining thickness ratio=8.2). The dimensional change % or the z-shrinkage is approximately twice as large in the TMA data for the composite tape (nearly 40%) as either the Primary Tape #3 (about 21 %) or the Constraining Tape #1 (about 18%). This is consistent with the fact that smaller x,y-shrinkage is associated with larger z-shrinkage for a similar level of volumetric shrinkage achieved by densification of a LTCC body. As one can see from the data and plot, the control of x,y-shrinkage is not as good as the previous examples. The x,y-shrinkage of the Primary #3 Tape is normally 12.7% and the shrinkage of the Constraining Tape #1 is 11.8%. Although the Primary Tape #3 does crystallize partially during its firing to 850° C., it does so more slowly and was therefore less effectively controlled by the Constraining Tape #1, inspite of what appears to be an adequate constraining tape as demonstrated when used in a tape composite using either Primary Tape #1 or #2. In an additional test, the 2.5-micron PSD (D50) Al2O3 filler was replaced with 1-micron (D50) Al 2 O 3 . The higher surface area typical of a smaller particle size would be expected to increase reaction speed between glass and filler. This, in turn, would be expected to increase the rate of partial crystallization in the tape and therefore result in improved control of x,y-shrinkage control in an identical composite tape structure. The plot in FIG. 5 shows TMA data for Primary Tape #3 made with 2.5 micron powder and in a second tape sample Primary Tape #3 with 1 micron powder. The data confirms that the 1 micron Al 2 O 3 has increased the reaction rate with the glass decreasing the extent of dimension change between the onset of sintering and 850° C. when the heating program converted to a soak temperature at 850° C. and the run was terminated. This reduction in shrinkage is considered to be caused by the lower volumetric shrinkage of a more rapidly developing crystalline phase, that potentially impedes densification. The plot in FIG. 5 also shows TMA curves for the three Constraining Tapes #1, #2, #3. Constraining Tapes #1 and #3 are close to possessing the same physical behavior in the TMA. The onset of sintering in Constraining #1 precedes the Constraining #3 Tape. However, both tapes become rigid at essentially the same temperature.
Example 4
In another experiment, Primary Tape #3 has been used with 2.5 micron alumina to demonstrate the capacity to form a blind cavity in a tape laminate assembly. The following test structure was prepared: 3×Prim #3/4×Constraining #1/3×Prim #3(through cavity in the top half sub-assembly of 10 layers)/3×Prim #3/4×Constraining #1/3×Prim #3 (no cavity in the bottom half sub-assembly of 10 layers) x,y-shrinkage =1.05%, constraining thickness 20.0 mils, size 3″×3″, total/constraining tape thickness ratio=3.7.
This test demonstrated the formation of a “blind” cavity in a 20 layer tape laminate assembly whereby the cavity depth is the same as the fired thickness of 10 layer sub-assembly (i.e., 6 primary tape and 4 constraining tape layers). The x,y-shrinkage of the above assembly is equal to an otherwise identically made assembly free of cavity structure. For those skillful in the art, both blind and open cavity structures can be formed so long as proper steps are taken to obtain adequate pressure distribution during lamination.
Example 5
Constraining Tape #3 (Glass #6 Table 1
Glass:
B2O3
11.84
wt. %
BaO
21.12
Li2O
1.31
P2O5
4.14
TiO2
25.44
Constraining Tape #3 (Glass #6 Table 1
Cs2O
6.16
Nd2O3
29.99
Glass Density 4.45 g/cc Alumina Density 4.02 g/cc
Filler: Al2O3 (D50 = 2.5 micron)
Filler content 33.7 vol %
The following tape structures are compared in this example:
Test #7
2xPrim#3-2.5/Constraining#1/2xPrim#3
constraining thickness 2.5 mils
total/constraining ratio = 8.2
Test #8
2xPrim#3-1/Constraining#1/2xPrim#3
constraining thickness 2.5 mils
total/constraining ratio = 8.2
Test #9
2xPrim#3/Constraining#2/2xPrim#3
constraining thickness 2.5 mils
total/constraining ratio = 8.2
Test #10
2xPrim#3/2xConstraining#3/2xPrim#3
constraining thickness 5.0 mils
total/constraining ratio = 4.6
In these tests the following x,y-shrinkage values were measured:
Test #7
1.24% (2.5 micron Al 2 O 3 used)
Test #8
0.72% (1 mocron Al 2 O 3 used)
Test #9
1.96% (2.5 micron Al 2 O 3 used)
Test #10
0.98% (2.5 micron Al 2 O 3 used, note double constraining
thickness used).
The use of the reduced particle size filler Al 2 O 3 in Test #8 has reduced the x,y-shrinkage value of 1.24% by 42% to a value of 0.72%. This Test #8 has changed the maturing characteristics of the Primary Tape #3 to start the crystallization sooner than the Test #7 tape. The lower shrinkage of Test #8 is likely a trade off of full densification of the primary tape; therefore, the particle size of frit, filler, and frit chemistry are all important in the practical implementation of the invention. In the comparison of Test #7 and Test #9, Test #9 is seen to have less effective constraint of x,y-shrinkage, as the Constraining Tape #2 has a higher onset for sintering and becomes rigid 20-30° C. higher than Constraining Tape #1. The Constraining Tape #3 sample would have been expected to show x,y-shrinkage between 1.24% and 1.96%, if a single layer of constraining tape was used in the structure. Since two layers of Constraining Tape #3 were used, the shrinkage is reduced due to the additional constraining effect of the greater constraining tape thickness.
The constraining tape is not restricted to being sandwiched between primary tape layers. The following data illustrate the use of the constraining tape on the external surface to sandwich primary tape layers:
Test
Constraining #1/2xPrim#3/Constraining #1
x,y-shrinkage 1.29%
#11
constraining thickness 5.0 mils
total/constraining ratio = 2.8
Test
Constraining #1/4xPrim#3/Constraining #1
x,y-shrinkage 1.08%
#12
constraining thickness 5.0 mils
total/constraining ratio = 4.6
Test
Constraining #1/6xPrim#3/Constraining #1
x,y-shrinkage 1.02%
#13
constraining thickness 5.0 mils
total/constraining ratio = 6.4
Test
Constraining #3/2xPrim#3/Constraining #3
x,y-shrinkage 0.96%
#14
constraining thickness 5.0 mils
total/constraining ratio = 2.8
Although the Primary Tape #3 was not ideal for reducing the x,y-shrinkage to near zero, it illustrates the capacity to reduce and control the shrinkage with a suitable constraining tape composition whether applied external or internally in a tape assembly.
Example 6
Complex tape structures are given herein, the Primary Tape #3 can be seen to improve its x,y-shrinkage behavior by incorporating Primary Tape #1 in the laminate assembly as shown in the following examples: (Thickness Prim#1-6.8 micron, Thickness Prim#3-2.0 micron).
Prim#3/Constraining#1/
x,y-shrinkage 0.25%
Prim#3/2xPrim#1/
Prim#3/Constraining#1/Prim#3
Constraining thickness 5.0 mils
total/constraining ratio 5.3
Prim#3/Constraining#1/Prim#3/Prim#1/
x,y-shrinkage 0.28%
Prim#3/Constraining#1/Prim#3
Constraining thickness 5.0 mils
total/constraining ratio 4.1
Primary Tape #1 composition (Glass #1, Table 1)
Glass:
B 2 O 3
6.08
wt. %
BaO
23.12
P 2 O 5
4.5
TiO2
34.25
Nd 2 O 3
32.05
Glass Density 4.72 g/cc Alumina Density 4.02 g/cc
Filler: Al 2 O 3 (D50 = 2.5 micron)
Filler content 36.0 vol %
FIG. 6 shows the TMA properties for Primary Tape #1, Constraining Tape #1 and Primary Tape #3. The Primary Tape #1 is strongly crystallizable and clearly assists the stabilization of the x,y-shrinkage when present in the Primary #3 and Constraining #1 laminate structure.
Example 7
A modified version of the Glass #3, Table 1, used in Primary Tape #2 is shown as Primary Tape #4 (Glass #7, Table 1, Thickness 4.5 mils) in a TMA plot found in FIG. 7 with Constraining Tape #3, that was presented previously, and a composite tape with the following structure:
Test #15
Prim #4x2/Constraining#3/Prim #4x2
x,y-shrinkage 0.34%
Constraining thickness 2.5 mils
total/constraining thickness ratio = 8.2
The Primary Tape #4 showed x,y shrinkage of 14.8% when fired by itself in air (not constrained). The TMA plot shows the z-axis shrinkage for the composite tape to be 32.5% while x,y-shrinkage was constrained to 0.34%.
Primary Tape #4
Glass:
SiO 2
52
wt. %
Al 2 O 3
14
B 2 O 3
8.5
CaO
17.5
MgO
4.75
Na 2 O
2
Li 2 O
0.25
K 2 O
1
Glass Density 2.56 g/cc Alumina Density 4.02 g/cc
Filler: Al 2 O 3 (D50 = 2.5 micron)
Filler content 36.0 vol %
The composition is similar to the glass used in Primary Tape #2 with added alkali oxide materials to lower the viscosity of the glass. This is apparent in the earlier onset of sintering of the Primary #4 Tape versus the Primary #2 Tape. It is also apparent that some loss of the ability to limit x,y-shrinkage in the Primary #4/Constraining #3 versus Primary #2/Constraining #1 Tapes is realized. Since the Constraining #3 and Constraining #1 Tapes are essential rigidified at the same temperature, they are similar in behavior, while different in their chemistries.
Two basic glass chemistries (Constraining Tapes #1 and #3) as components in tape formulations have been shown to act effectively as x,y-shrinkage control in composite tape structures with both crystallizing glass and slow to crystallize glass serving as a component in the primary tape materials.
Example 8
The following example is intended to illustrate the dependency of x,y-shrinkage on the difference in tape sintering kinetics. Both of the Constraining Tape #4 (using Glass #8, Table 1, density—4.58 g/cc), and Constraining Tape #5 (using Glass # 10, Table 1, density—4.55 g/cc) were tested. All tapes were made in combination with 33.7 vol % alumina (2.5 micron D50) as described previously. Tape structures were prepared with Primary Tape #3 (that incorporates Glass #5 Table 1). The following test structures were made and their respective x,y-shrinkage values were measured.
Test
2xPrim #3/Constraining #4/2x Prim #3
x,y-shrinkage = 3.98%
#16
constraining tape thickness 2.5 mils
total/constraining tape ratio = 8.2
Test
2xPrim #3/Constraining #5/2x Prim #3
x,y-shrinkage = 2.19%
#17
constraining tape thickness 2.5 mils
total/constraining tape ratio = 8.2
The TMA characteristic of each tape is shown in FIG. 8 . The degree of x,y-shrinkage control can be seen to vary with the difference in the onset of sintering between the primary and constraining tapes. Hence the smaller shrinkage shown in Test 17 using Constraining Tape #5 starts sintering sooner than Constraining Tape #4 (Test 16). Both the Constraining Tapes #4 and #5 show an expansion anomaly near the onset of sintering of the respective tapes. This is not present in the Constraining Tapes #1 or #3 seen in previous figures. The presence of these expansion peaks in the sintering characteristics of Constraining Tapes #2, #4 and #5 is considered undesirable. The presence or absence of these peaks can be managed by ratio changes of constituents in the glass compositions. They may also be responsible for some unpredictable behavior due to the expansion preceding the shrinkage of the tape. However, they clearly illustrate the general behavior of several previous examples when used to constrain a primary tape. Based upon the differences in the onset and rigidification behavior of the tape pairs, the composite tape shrinkage in the x,y directions can be designed by glass and/or tape formulation to approach zero when thermally processed under standardized conditions (typically 850° C. for 15-20 minutes).
Example 9
In this example, another glass similar to Glass #3 and Glass #7 (Table 1) is used to formulate a designated Primary Tape #5 (Glass #14, Table 1, with 36.0 vol % alumina, 2.5 micron D50, Tape Thickness=4.5 mils). This tape is paired with a previously tested Constraining Tape #3 (Glass #6, Table 1). The following structures show an improved ability to approach zero x,y-shrinkage.
Test
2xPrim #5/Constraining #1/2xPrim #5
x,y-shrinkage = 0.17%
#18
constraining tape thickness 2.5 mils
total/constraining tape ratio = 8.2
Test
3xPrim #5/2xConstraining
x,y-shrinkage = 0.03%
#19
#1/3xPrim #5
constraining thickness 5.0 mils
total/constraining tape ratio = 6.4
Test
2xPrim #5/Constraining #3/2xPrim #5
x,y-shrinkage = 0.19%
#20
constraining thickness 2.5 mils
total/constraining tape ratio = 8.2
Test
3xPrim #5/2xConstraining
x,y-shrinkage = 0.04%
#21
#3/3xPrim #5
constraining thickness 5.0 mils
total/constraining tape ratio = 6.4
In Tests 18 and 19, the x,y-shrinkage constraint is again seen to be thickness ratio dependent. The structure in 19 with its more favorable (thicker Constraining #1 Tape) is seen to have near zero x,y-shrinkage. In Tests 20 and 21, the Constraining Tape chemistry is changed substantially, although the required onset temperature separation in TMA properties from the primary tape is essentially the same. This can be seen in FIG. 9 . The Constraining Tape #1 is seen to have a slightly lower sintering onset than Constraining Tape #3, while the onset of rigidification during the firing is the same for both constraining tapes. The nearly identical x,y-shrinkage values in Test #18 and #20 or Test #19 and #21 appear to correlate with the same rigidification temperature of the Constraining Tape #1 and #3.
Example 10
In this example, a Primary Tape #6 (4.5 mils thick) which is composed of 33.9 vol % alumina (2.5 micron D50) with Glass #15, Table 1, is formulated as a tape. The tape was fired at 875° C. in a belt furnace to yield an average x,y-shrinkage of 13.87%. The following additional tests were performed on structures formed of Primary Tape #6 and Constraining Tape #3 (Glass #6, Table 1):
Test
2xPrim #6/1xConstraining
x,y-shrinkage = 0.00%
#22
#3/2xPrim #6
constraining thickness 2.5 mils,
size 3″ × 3″
total/constraining tape ratio = 8.2
Test
3xPrim #6/2xConstraining
x,y-shrinkage =
#23
#3/3xPrim #6
−0.02%
constraining thickness 5.0 mils,
size 3″ × 3″
total/constraining tape ratio = 6.4
Test
3xPrim #6/2xConstraining
x,y-shrinkage =
#24
#3/3xPrim #6
−0.13%
constraining thickness 5.0 mils,
size 5″ × 5″
total/constraining tape ratio = 6.4
Test 22 shows the attainment of zero x,y-shrinkage using a 2-1-2 layer structure. Test 23 with a 3-2-3 structure shows small negative shrinkage (expansion), which is essentially zero due to the measurement precision of ±0.00025 inch. Test #24 uses the same structure as Test #23, except it is a 5″×5″ substrate size. This illustrates an ability to achieve dimensional control on small or larger size substrates. A second set of laminate structures was also fired at 850° C. in a belt furnace:
Test
2xPrim #6/1xConstraining
x,y-shrinkage = 0.03%
#25
#3/2xPrim #6
constraining thickness 2.5 mils,
size 3″ × 3″
total/constraining tape ratio = 8.2
Test
3xPrim #6/1xConstraining
x,y-shrinkage =
#26
#3/3xPrim #6
−0.01%
constraining thickness 2.5 mils,
size 3″ × 3″
total/constraining tape ratio = 11.8
Test
3xPrim #6/2xConstraining
x,y-shrinkage =
#27
#3/3xPrim #6
−0.03%
constraining thickness 5.0 mils,
size 3″ × 3″
total/constraining tape ratio = 6.4
The results of test series #250-#27 (850° C. fired) and test series #22-#24 (875° C. fired) show excellent dimensional stability with change in peak firing temperature. The Primary Tape #6 by itself showed 13.87% shrinkage in x,y-directions after 875° C. firing. In the 3-1-3 laminate assembly with one layer of Constraining Tape #3 as in Test #26, the total to constraining tape thickness ratio is 11.8, and shows essentially zero x,y-shrinkage. This is an excellent example of the clear advantages of this invention. FIG. 10 shows TMA plots of Primary Tape #6, Constraining Tape #3, and a tape lamination of 2×Prim#6/Constraining #{fraction (3/2)}×Prim#6. The x,y-shrinkage of the composite tape is essentially zero, whereas the z-shrinkage indicates 34%. This agrees with a calculation to convert the approximate volume change only to a uniaxial shrinkage in the z-direction. The temperature difference between the onset of tape shrinkage (near the respective glass transitions) between the two compositions of tape is 90-100C. However, the most significant occurrence is the fact that Constraining Tape #3 has become rigid before significant shrinkage has begun in the Primary #6 Tape, both occurring at 700° C.
If the primary tape is allowed to begin sintering before the x,y direction is constrained, then a non-zero level of x,y-shrinkage is the likely result. In order to achieve zero x,y-shrinkage, the tape formulations must be optimized for both primary and constraining tape. When the constraining tape starts sintering and completes its densification to become rigid, prior to the onset of sintering of the primary tape, the primary tape is acting to constrain the x,y-shrinkage of the constraining tape. As the primary tape begins to sinter, it is, in turn, constrained in x,y-directions by the rigid condition of the matured constraining tape.
The effect to minimize the fired x, y shrinkage as illustrated in Example 5 is discussed and demonstrated further here. Since the Primary Tape is acting to constrain the x, y shrinkage of the Constraining Tape at a temperature range between 600° C. (onset of Constraining Tape softening) and 700° C. (completion of Constraining Tape rigidification), the inorganic solid packing density in the Primary Tape plays a critical role. It is noted that most if not all of the organic substances (polymer binder, plasticizer, dispersion agent, and others) have been burn out before reaching 600° C. and the constraining effect of the Primary Tape has to come from its non-compressibility. This non-compressibility requires essentially no movement or transfer of inorganic solids in the Primary Tape under the stress generated by the Constraining Tape which undergoes frit softening, flow, sintering, and crystallization. The ability to control x, y shrinkage through the optimization of filler (i.e. alumina or other inorganic solids) particle sizes is demonstrated in the following Example 11.
Example 11
Primary Tape #6 with regular size alumina (D50=2.5 μm) and a modified Primary Tape #6 which maintains identical tape composition except substituting the above size alumina by a blend of medium (D50=1.8 μm) and fine (D50=0.5 μm) size alumina.
Test
2xPrim #6/1xConstraining #3/2xPrim #6
x,y-shrinkage = 0.11%
#28
constraining thickness 2.0 mils,
total/constraining tape ratio = 10
Test
2xmod.Prim #6/1xConstraining #3/
x,y-shrinkage = 0.04%
#29
2xmod. Prim #6
constraining thickness 2.0 mils,
total/constraining tape ratio = 10
Test
3xPrim #6/1xConstraining #3/3xPrim #6
x,y-shrinkage = 0.15%
#30
constraining thickness 2.0 mils,
total/constraining tape ratio = 14.5
Test
3xmod. Prim #6/1xConstraining #3/
x,y-shrinkage = 0.02%
#31
3xmod. Prim #6
constraining thickness 2.0 mils,
total/constraining tape ratio = 14.5
Test
4xPrim #6/1xConstraining #3/4xPrim #6
x,y-shrinkage = 0.13%
#32
constraining thickness 2.0 mils,
total/constraining tape ratio = 19
Test
3xmod. Prim #6/1xConstraining #3/
x,y-shrinkage = 0.01%
#33
3xmod. Prim #6
constraining thickness 2.0 mils,
total/constraining tape ratio = 19
The TMA data for Test #30 and Test #31 are shown in FIG. 11 . The z-shrinkage shown by the composite structure of Test #31 with modified Primary Tape #6/Constraining #3/modified Primary #6 with a blend of 1.8 micron and 0.5 micron alumina filler is about 28%. The regular 2.5 micron alumina filler containing Primary #6/Constraining #3/Primary #6 structure of Test #30 is about 38%. The less volumetric shrinkage of Test #31 was contributed by two factors. The first is the possible stimulation of more rapid crystallization in the modified Primary Tape #6 by the more reactive 0.5 micron alumina filler. The second is due to the increased filler packing density achieved by the blending of 1.8 and 0.5 micron filler.
To reconfirm the effect of inorganic particle size optimization, a Primary Tape #7 (Glass #17 in Table 1) was used in Example 12. The weight % composition of this tape is identical to that of the modified Primary Tape #6 except the choice of glass component in the tape.
Example 12
By exerting the interactive constraining effect of the Primary Tape (i.e. non-compressibility during the softening, flow, sintering, and crystallization of the Constraining Tape) and Constraining Tape (i.e. reaching the state of rigidification prior to softening of the Primary Tape) the following laminate assembly configurations provided nearly zero x, y shrinkage.
Test
2xPrim #7/1xConstraining #3/2xPrim #7
x,y-shrinkage = 0.01%
#34
constraining thickness 2.0 mils,
total/constraining tape ratio = 10
Test
3xPrim #7/1xConstraining #3/3xPrim#7
x,y-shrinkage = 0.01%
#35
constraining thickness 2.0 mils,
total/constraining tape ratio = 14.5
Test
4xPrim #7/1xConstraining #3/4xPrim #7
x,y-shrinkage = 0.04%
#36
constraining thickness 2.0 mils,
total/constraining tape ratio = 19
The next section will deal with the asymmetrical tape laminate structure and its effect on property of the fired structure. The placement symmetry of the primary and constraining tape in a multi-layer tape assembly is the preferred mode because such structure leads to a balance in mechanical stress created by the difference in sintering and thermal coefficient of expansion between component tapes. All of the fired and flat LTCC substrates possess the above symmetry whereas substrate camber is noticeable with any asymmetrical build to-date. For all practical purposes, although a similar x,y-shrinkage control can be obtained, asymmetrical design must be converted to a symmetrical style by adding or subtracting primary or constraining tape layers to eliminate substrate camber. Tests #37 and #38 represent the results of tested asymmetrical configurations.
Test
Prim #3/Constraining #1/Prim#3/Prim#1/
x,y-shrinkage = 0.26%
#37
Prim#3/Constraining #1/Prim#3/
10 layer build
Prim #3/Constraining #1/Prim#3
camber > 20 mils/inch
constraining thickness 2.5 mils
total/constraining tape ratio = 4.3
Test
Prim #3/Constraining
x,y-shrinkage = 0.16%
#38
#1/Prim#3/2xPrim#1/
11 layer build
Prim#3/ Constraining #1/Prim#3/
camber > 23 mils/inch
Prim #3/Constraining #1/Prim#3
constraining thickness 2.5 mils
total/constraining tape ratio = 5.2
This limitation to symmetrically built structures is applicable to the materials tested to-date and is not an indication of a fundamental problem. Correction of physical property differences between layer components of an LTCC build are expected to provide a means to extend this method to asymmetric structures.
It should be noted that more than one type of constraining or primary tape maybe used in a common structure as long as configurational symmetry and physical compatibility requirements are satisfied.
The primary/constraining tape laminate assemblies disclosed in this invention can be fired in a typical LTCC belt furnace profile to achieve full densification and zero or nearly zero x,y-shrinkage. A typical LTCC belt furnace profile for 951 GREEN TAPE™ (a commercial product from E. I. DuPont) is a three and a half-hour burnout and sintering profile which includes: (1) 25° C. to 60° C. at 2.5° C./min, (2) 60° C. to 400° C. at 19.2° C./min, (3) 400° C. to 435° C. at 1.4° C./min, (4) 435° C. to 850° C. at 7.0° C./min, (5) dwell at 850° C. for 17 min, (6) 850° C. to 40° C. at 17.3° C./min, and (7) 40° C. to room temperature at 0.5° C./min. For anyone skilled in the art, the above profile can be modified according to one's belt furnace specifications so long as adequate organic burnout, ramp rate to peak temperature, peak temperature duration, and descending rate can be optimized to produce the desirable results.
|
The present invention relates to a method to achieve the suppression of planar shrinkage in LTCC ceramic tape laminate structures without externally applied forces or sacrificial constraining tape. The method utilizes a non-sacrificial constraining tape that constrains a tape assembly.
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The invention relates to a fluid jet assisted ion projection electrographic marking apparatus and, in particular, to low cost, high speed VLSI (Very Large-Scale Integration) based serial to multiplexed data translator for such a marking apparatus.
BACKGROUND OF THE INVENTION
The imaging process used herein is described, with respect to a fluid jet assisted ion projection printer, in commonly assigned U.S. Pat. No. 4,463,363. In the printer described in that patent, imaging ions are first generated and then deposited upon a moving receptor by means of a linear array of selectively controllable, closely spaced, minute air nozzles. The ions of a single polarity, preferably, positive are generated in an ionization chamber by a high voltage corona discharge and then are transported, by being entrained in a high velocity fluid, to and through the nozzles wherein they are electrically controlled by an electric potential applied to modulating electrodes. Selective application of control voltages to the modulating electrodes in the array will establish a field across the nozzle to inhibit passage of ions to each nozzle. Alternatively, ions are allowed to pass through the nozzle if the field is below a threshold value, so as to enable areas of charge to appear on the receptor surface for subsequent development.
A typical modulating structure for this type of printer is disclosed in commonly assigned to U.S. Pat. No. 4,524,371. The modulating structure is formed upon a planar marking head mounted on the ion generating housing, and each electrode thereon may be addressed individually for modulating each nozzle independently. An improved integrated printer marking head, incorporating thin film ion modulating electrodes, drive circuitry, and switching elements formed upon a single substrate is disclosed in commonly assigned U.S. Pat. No. 4,584,592. The printers described in the above-named patent rely upon the selective imposition of electrical data on the modulation electrodes. The data may be computer generated and is normally applied by any conventional data and address technique. In yet another commonly assigned U.S. Pat. No. 4,591,885, the principle of the fluid jet assisted ion projection marking process is incorporated in an apparatus for copying original images onto an image receptor. This is accomplished by causing an optical input to address a photoconductive modulation assembly formed at one end of a light collecting ribbon.
Other patents of interest are U.S. Pat. No. 4,392,131 disclosing an integrable activation module for passive electro optical displays. The module comprises a shift register for supplying data in parallel to a display matrix and a pulse generator for supplying pulses to row and column drivers in response to a signal from a transfer terminal to thereby address an n by m matrix. U.S. Pat. No. 4,247,856 discloses a sequentially scanned plasma display for alpha numeric characters comprising a clock for driving a shift register for controlling the columns of a plasma display. Data is supplied to the display from a controllable logic circuit and displayed column by successive column. U.S. Pat. No. 4,180,813 discloses a liquid crystal display device using a digital converter comprising a liquid crystal display panel receiving data in parallel from a shift register and receiving driving voltages from a scanning electrode circuit for energizing electrodes each time a ring counter receives a control signal.
A difficulty with the prior art systems is that the means to translate high speed serial (video) data into real time multiplexed parallel applied data patterns to drive a marker or printer is often complex and costly. It would be desirable to provide a low cost, high speed, VLSI based serial to multiplexed data translator for printer applications. It is an object, therefore, of the present invention to provide an interface between high speed serial data and output data patterns for a high resolution output modulation device that is simple and economical. It is another object of the present invention to provide a high speed, two wire serial interface between a circuit designed to drive a raster scan device and the x-y matrixed input of the discrete pixel modulated output devices. It is also an object to provide a low cost input voltage isolation. It is still another object of the present invention to provide a simple VLSI interface requiring only two VLSI shift registers and a simple digital divider and latch control circuitry.
SUMMARY OF THE INVENTION
Briefly, the present invention is a fluid jet assisted electrographic marking apparatus for placing electrostatic charges upon a receptor surface in an imagewise pattern by converting high speed serial data into real time parallel applied data including means for supplying a transport fluid, a housing including an upstream ion generation region and a downstream ion modulation region, the housing including inlet means for receiving transport fluid from the means for supplying located upstream of said ion generation region, ion modulation means located at the ion modulation region, an outlet means from which transport fluid exits the housing, said ion modulation means including charged storage means having electrically conductive electrodes positioned adjacent the path of the transport fluid in the ion modulation region for controlling the passage of ions out of said housing, and a data translator for converting the serial data into real time parallel applied data, the charge storage means and the electrodes being integrally fabricated upon a substrate, the data translator being wire bonded or otherwise integrally connected, attached, or fabricated upon and to the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, reference is made to the accompanying drawings wherein the same reference numerals have been applied to like parts and wherein:
FIG. 1 is a schematic representation of an electronic printer according to the present invention;
FIG. 2 is a schematic representation of one form of the marking head of the present invention showing an array of marking electrodes and sensor circuit;
FIGS. 3A, 3B and 3C are representative of further configurations of large area marking heads which may be used in the system illustrated in FIG. 1;
FIG. 4 is a block diagram illustrating the data translator in accordance with the present invention;
FIG. 5 is a more detailed block diagram of the data translator according to the present invention, and
FIG. 6 is a timing diagram according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With particular reference to the drawings, there is illustrated in FIG. 1 a housing 10 for a fluid jet assisted ion projection printing apparatus. The housing includes an electrically conductive, elongated chamber 12 and a corona discharge wire 14, extending along the length of the chamber. A high potential source 16, on the order of several thousand volts dc, is connected to the wire 14 through a suitable load resistor 18, and a reference potential source 20 (which may be ground) is connected to the wall of chamber 12. Upon application of the high potential to corona discharge wire 14, a corona discharge surrounds the wire, creating a source of ions of a given polarity (preferably positive), which are attracted to the ground chamber wall and fill the chamber with a space charge.
An inlet channel 22 extends along the chamber substantially parallel to wire 14, to deliver pressurized transport fluid (preferably air) into the chamber 12 from a suitable source, schematically illustrated by the tube 24. An outlet channel 26, from the chamber 12, also extends substantially parallel to wire 14, at a location opposed to inlet channel 22, for conducting the ion laden transport fluid to the exterior of the housing 10. The outlet channel 26 comprises two portions, a first portion 28 directed substantially radially outwardly from the chamber and a second portion 30 angularly disposed to the first portion. The second portion 30 is formed by the unsupported extension of a marking head 32 spaced from and secured to the housing by insulating shim 34. As the ion laden transport fluid passes through the outlet channel 26, it flows over an array of ion modulation electrodes 36, each extending in the direction of the fluid flow, and integrally formed on the marking head 32.
Ions allowed to pass completely through and out of the housing 10, through the outlet channel 26, come under the influence of accelerating back electrode 38 which is connected to a high potential source 40, on the order of several thousand volts dc, of a sign opposite to that of the corona source 16. An insulating charge receptor 42, is interposed between accelerating back electrode and the housing, and is moved over the back electrode for collecting the ions upon its surface in a image configuration. Subsequently the latent image charge pattern may be made visible by suitable development apparatus (not shown). Preferably, a transfer system may be employed, wherein the charge pattern is deposited upon an insulating intermediate surface such as a receptor drum or belt. In such a case, the latent image charge pattern may be made visible by development upon the receptor surface and then transferred to a final image copy sheet.
Once the ions have been swept into the outlet channel 26 by the transport fluid, it becomes necessary to render the ion-laden fluid stream intelligible. This may be accomplished by selectively controlling the potential on modulation electrodes 36 by means of photosensors 44 also integrally formed upon the marking head. In order to duplicate an original document 46 upon the charge receptor 42, the original is illuminated by a suitable light source 48. A reflector 50 concentrates the optical energy upon the original, with some of the optical energy falling within the collection angle of lens system 52. The light reflected from the original document passes through the lens system, then passes through the substrate of the marking head 32 for projecting patterns of light and dark areas from the original document 46 onto the sensors 44. Preferably, the lens system is in the form of a short optical length elongated lens strip of the Selfoc or graded index focusing type. Of course, in this configuration the substrate is made of any suitable, optically transparent material.
It should be noted that the potential or the modulation electrodes 36 need not be controlled by photosensors 44, but could be controlled directly from a source of digital data representing an image to be reproduced. The source of digital data could be stored in memory in a general purpose computer suitably interconnected to the modulation electrodes 36. An economical means for transferring digital data at high speed as required with this latter mode of imaging will be more fully disclosed herein. This digital data translation interface affords substantial advantages in simplicity, reliability and economy of implementation in the practical application of the present invention and apparatus.
As described in U.S. Pat. No. 4,463,363, once the ions in the transport fluid stream come under the influence of the modulation electrode, they may be viewed as individual "beams," which may be allowed to pass to the receptor 42 or to be suppressed within the outlet channel 30. "Writing" of a single spot in a raster line is accomplished when the modulation electrode is selectively connected to a potential source at substantially the same potential as that on the opposing wall of the outlet channel. With both walls bridging the channel being at about the same electrical potential, there will be substantially no electrical field extending thereacross. Thus, ions passing therethrough will be unaffected and will exit the housing to be deposited upon the charge receptor. Conversely, when a suitable potential is applied to the modulation electrode, a field will extend across the outlet channel to the opposite, electrically grounded, wall. If the electrical potential imposed on the modulation electrode is of the same sign as the ions, the ion "beam" will be repelled from the modulation electrode to the opposite wall where the ions may recombine into uncharged, or neutral, fluid molecules.
If the electrical potential imposed on the modulation electrode is of the opposite sign as the ions, the ion "beam" will be attracted to the modulation electrode where they may recombine into uncharged, or neutral, fluid molecules. Therefore, that "beam" of transport fluid, exiting from the housing in the vicinity of that modulation electrode, will carry substantially no "writing" ions. Voltages of intermediate magnitude will cause the ion current to be proportional thereto, allowing gray scale writing upon the charge receptor. An imagewise pattern of information will be formed by selectively controlling each of the modulation electrodes in the array so that the ion "beams" associated therewith either exit or are retarded from exiting, the housing in accordance with the pattern and intensity of light and dark spots on the original to be copied or else in accordance with stored digital information representing an image.
With respect to FIG. 2, there is illustrated one configuration of a large area marking head 32 which may be used with the apparatus shown in FIG. 1. A suitable planar substrate of dielectric material (Preferably transparent, such as glass) has fabricated thereon, by standard thin film deposition techniques, an array of metallic modulation electrodes 36 at a density of about 300 per inch. At that density, each modulation electrode would be, for example, 2.5 mils wide, spaced from one another by 0.8 mils. The electrodes are about 60 mils long.
An array of photosensors 44, each approximately 2.5 mils by 2.5 mils, is also integrally fabricated on the substrate by standard thin film deposition techniques. Each sensor is located so that it is associated with and is electrically connected to each modulation electrode 36. A drive potential bus 54, to which each sensor is connected, extends across the substrate and is connected to a drive potential V preferably on the order of 20 or 30 volts dc. A ground bus 56, also extending across the substrate, is connected to each potential divider node 57 through load resistor 58. The drive potential bus 54, the ground bus 56, the load resistors 58 and all interconnecting conductive traces are also integrally fabricated upon the substrate by standard thin film deposition techniques.
When the sensor 44 is dark, its conductivity is very low and insufficient current flows therethrough from the drive potential bus 54. Thus, there will be an extremely small potential drop across the load resistor 58 and the voltage on the modulation electrode will be to zero volts. As explained above, in this condition, ions will be allowed to pass out of the housing to the charge receptor surface for generating a mark, i.e., a dark portion of the original document will cause the corresponding sensor to be dark, which in turn will subsequently create a dark mark on the charge receptor.
When light falls on the sensor 44, its resistance is lowered and current flows through it from the drive potential bus 54 to the ground bus 56, through the load resistor 58 (which may optionally be utilized for regulating, or limiting signal current). As the sensor resistance is much lower when fully illuminated, the potential drop thereacross is minimal, causing the node potential to be substantially equal to the drive potential. This potential, of about 20 to 30 volts dc, will appear upon the modulation electrode, causing the ions in its associated beam to be deflected to the grounded opposite wall. In this condition, ions will be prevented from exiting the housing and no mark will be generated upon the charge receptor, i.e., a light portion of the original document will cause the corresponding sensor to be light, which in turn will create no mark on the charge receptor. The charge will remain on the modulation electrode as long as the sensor is illuminated. As soon as the photosensor is made dark, the potential on the modulation electrode will be discharged to ground.
The print array just described and shown in FIG. 2 may be adapted to be modulated by digital electronic signal means by simple extension and adaptation of the photo sensor components 44. Thin film photosensors may be, and commonly are, produced in the form of phototransistors by techniques well known to those skilled in the art. Phototransistors may be activated by exposure to light at their reverse-joined PN-junction (commonly referred to as base, or gate junction), whereupon the photon energy of light lowers the energy-barrier level, and allows electron flow (hence signal conduction) through the barrier junction (i.e. from "collector" to "emitter", or "drain" to "source", for example). However, when electrical connection is made to the base, or gate, the transistor may now be modulated (from non-conduction into conduction) by application of a low-level bias signal at its base, or gate, as is generally known and practiced in the field of solid-state electronics.
Hence, the print array of the present invention may be designed to be light sensitive, thereby transposing image pattern information presented via light exposure upon the photo-sensitive linear array directly into equivalently proportional electrical modulation patterns at the print electrodes 36, and therewith, also, an equivalently proportional electrical charge potential upon the charge receptor 42, which "latent charge image" may be developed, transferred, and fixed upon ordinary plain paper or other substrate by standard means known by these skilled in the art of xerography or ionography. Furthermore, the print array may be designed to be electronically driven (either additionally or alternatively) whereupon the desired electronic image pattern is equivalently transposed, either selectably in lieu of, or in addition to, or optionally simultaneous with (hence super-imposed upon), a light image, as intended or desired by specific embodiment and application of the invention.
With respect to FIG. 3A, there is illustrated another configuration of a large area marking head, generally illustrated at 32A, which may be used with the apparatus shown in FIG. 1. This is comprised of a suitable planar substrate of dielectric material (such as glass, for example) and it has fabricated thereon, by standard precision thin film deposition techniques, an array of metallic modulation electrodes, 36A, at a density of 300 per inch, for example at suitable dimensions and interelectrode spacing.
For this embodiment, there is an array of amorphous-silicon thin film transistors 37 fabricated on the substrate by precision thin film deposition methods. (These may be integral, additional, or alternate to the array of photosensors 44 - light sensitive phototransistors previously described.)
Each transistor is associated with and is electrically connected at one terminal with a corresponding modulation electrode 36A, its "source" for example, in the classical model of a metal-oxide semiconductor (MOS) transistor. The opposing electrical terminal, the "drain", of the MOS transistor is connected to one of many drive potential buses, labeled and referred to collectively as "data lines", D1, D2 . . . Dn, where n may be any desired integer number, according to a convenient fractional ratio of the intended number of modulation electrodes in the array which are to be driven with image data signals. In the particular configuration, for example, where it is desired to print an 81/2 wide line with the marking head and print array, with 300 spots per inch image resolution, there would be some 2,550 (81/2×300) modulation electrodes constructed on the print array, and may be some 40 data lines for convenient design purposes for reasons to be explained. Alternately, an 11 inch wide print array, with 3,330 electrodes, may have some 50 data lines, or an array with up to 4096 electrodes may employ some 64 data lines, for convenience (as shown in FIG. 3A).
It should be noted that adjacent transistors are preferably connected in orderly fashion to adjacent electrodes at their "sources", and to adjacent (or successively assigned, in either ascending or descending order) different data lines at their "drains", for the conveniently defined group of "n" transistors (corresponding to a contiguous section of "n" electrodes where n=64 in FIG. 3A). Another group of "n" transistors, attached to electrodes "n+1" through "2n" in ordered fashion at their sources, is repetitively connected at their drain terminals to the same set of previously assigned data lines in the same successive pattern.
In completely repetitious fashion, additional groups of transistors are identically connected to successively adjacent sections of modulation electrodes, and also successively to the same ordered set of data lines, for the entire length of the print array, encompassing all active modulation electrodes. Hence, all active modulation electrodes are individually controlled by corresponding drive transistors ordered into repetitious groups of "n", repeated a desired number "m" times, according to the full extent of the print array, where the total number of active electrodes T≦m×n. It should now also be noted that all "n" transistors in a given group have their respective gate terminals commonly connected together and assigned as one of m "data strobe lines", G1, G2, . . . Gm.
In this arrangement, each group of transistors may be activated during a time interval which is mutually exclusive from the remaining (M-1) groups, and during which interval the desired image-data signals, corresponding to an intended electrode modulation pattern in a given section "m(t)","(1≦m(t)≦m)", have been applied on the data lines. The strobe activation of the transistor gates causes all n transistors in the group to be conductive between drain and source terminals and allows the then-applied n unique bits to transfer to the corresponding n modulation electrodes. The typical drive potential range may be on the order of 20 to 30 volts as previously indicated.
Furthermore, successively applied data strobe pulses may be applied in ordered synchronism with intended data bit patterns, in sequential groups of n bits, at very high data presentation rates, which may be on the order of many million bits per second with the present state of the art.
In accordance with such time-multiplexed operation of the print array in the manner just described, it should be noted that each individual modulation electrode may be actively driven with intended data signals for a fractional time interval "t", in a larger time period "T", whereupon it is again actively driven with new data, and thereafter repeatedly refreshed in equivalently fractional intervals during successive periods. It is apparent also that the relationship t/T≦1/m applies to this mode of operation in modulating the print array, and that the fractional interval t/T may be relatively small when the number m is relatively large. However, for optimized performance at the print array, it will generally be desired to retain the applied value of the data signal upon the electrode in the intervening interval, defined by
(T-t)/T
during which the transistor is off (non-conducting). This may be effectively accomplished with the application of a small "common ground plane" "GP" across the output region of the array in close proximity to the electrodes, and therefore presenting a relatively small amount of electrical capacitance between each electrode and signal common. The resulting capacitance serves to deter immediate change in voltage potential applied to each electrode, which serves as the charged plate of the capacitor, particularly during the inactive interval when the drive transistor is off.
Therefore, with time-multiplexed operation, proper electrode potential is retained for efficient performance by utilizing generally known "sample-and-hold" techniques for data retention, which may preferably be implemented integrally upon the print array by appropriate design features.
It should also be noted in the described multiplexed embodiment of the print array, the same array might also be adapted for direct light image modulation, when and if so desired, and as previously described. While a variety of particular design options exist for this purpose, with the equivalent result of multiple functionality of the same print array, some exemplary approaches are presented to demonstrate such functionality. For the embodiment wherein the electrode drive transistors are designed and arranged to also serve as photo transistors for for the purpose of receiving light image patterns, all strobe lines, and therefore gate connections, may be electronically disconnected, or "tristated", such that no electrical bias is applied, and simultaneously all data lines may be electronically connected to the same desirable drive potential V, whereupon the electrical configuration becomes analogous and functionally equivalent to that previously descried by FIG. 2 and related text. Alternatively, a secondary photosensor array may be appropriately placed upon the array and each sensor output terminal connected with associated electrodes in common connection with an associated transistor. This arrangement is generally recognized as a "parallel", or "wired-OR", connection of alternate drive sources in the art. For this embodiment, electronic data modulation may be disabled, when desired, by deactivating the strobe signals. In any such embodiment of multiple functionality, light modulation is disabled by convenient conventional means, such as blocking or extinguishing the source of light. Further, for any application in which light modulation may have extremely rapid change rate, and therefore wherein excessive electrode capacitance may be deleterious to rapid modulation response, the means for adding electrode capacitance for multiplexed operation may be easily modified electronically by conventional art as desired, or may be adequately minimized simply by disconnecting the common plane, "GP", (in whole or in part) from signal common "ground", for example.
Further specific additions, and variations in detail, may be included integrally upon or adapted to the array with various purposes such as enhancing, optimizing, or customizing performance and operation to particular applications, or for ensuring reliable operation, or for protecting delicate components and circuits on and near the array from physical or electrically-induced damage. For example, for applications wherein the array may be placed, or utilized, in proximate vicinity or electrical contact with sources of high voltage potential, or else likely to generate transient electrical discharges or potential fields with relatively high energy levels, an appropriate means or circuit may be adapted integrally and/or peripherally to the array to provide intended performance and simultaneously render dangerous electrical fields or discharges harmless. Some exemplary means are shown in FIG. 3B and FIG. 3C, incorporating "voltage clamp" circuits, by techniques common in the art, to direct excessive voltage potentials away from delicate components on the array. It shall be recognized and understood that various such embodiments and enhancements are encompassed by the present invention.
With reference to FIG. 4, there is illustrated in block diagram a serial digital (video) data signal translator in accordance with the preferred embodiment of the present invention. FIG. 4 illustrates an electronic subsystem generally shown as 60 storing image or document data to modulate a printer array generally shown at 62 (encompassing previously described salient features in FIGS. 2, 3A, 3B and 3C) to print out on a suitable receptor the image or document defined by the data stored in the electronic subsystem 60. The electronic subsystem 60 comprises suitable logic circuitry and memory storage preferably supported on a printed wiring board to store the data representing the document or the image. The printing array 62 preferably is a glass or other suitable substrate including the necessary electrical components and connections represented as the serial data translator interface circuitry 72 for inter connecting the printing array to the electronic subsystem and for modulating the probes 66 (previously described as modulation electrodes 36) on the glass substrate to print out the image or the document.
Preferably, for example, it would be desirable to print an 81/2" wide line of data at one time at 300 spots per inch resolution. One option to accomplish this would be to provide 2,550 (81/2×300) probes on the array 62 inter connected to the storage in the electronic subsystem 60 holding 2,550 bits of data and connected to the probes by 2,550 wires between the electronic subsystem 60 and the printing array 62. Obviously, this is impractical due to the cost and physical bulk of the interconnection.
In lieu of the just given example, an improved method of interconnection would be to provide 64 data line connections to the glass substrate 62 activated by 40 strobe signal lines, electronically driven such that successive groups of 64 data bits are presented sequentially at data lines in synchronism with the successive (incrementing) activation of 1 of the 40 strobe lines, in a time-multiplexed data signal arrangements, for each line of data to printed. An interface circuit in the electronic subsystem 60 would provide the necessary data output selecting logic (commonly known as "data-multiplexing logic"), to present parallel 64 data signals from the electronic subsystem to the printer array and also would provide 40 strobe timing pulses to selectively activate adjacent groups of 64 printer probes 40 times to print one 81/2" wide line of data. Correspondingly, the printing array 62 would have its probe modulating transistor array connected in appropriate demultiplexing arrangement to receive the multiplexed data signals and distribute each to the intended output probe of the group of 2550 probes, 66, as previously described with reference to FIGS. 3A 3B and 3C. A difficulty with this improvement is that 64 data lines plus 40 strobe lines, hence 104 wires, are still needed to inter connect the probes on the printing array 62 with the corresponding 2550 data bits (contained within 64×40=2560 data bit capability of the described multiplexing logic) in the electronic subsystem, and with the need for electrical signal isolation (via suitable high-speed isolating circuitry) to enhance reliability, or to bias the printing array at high potential from logic ground, this system can also be relatively expensive and complex.
However, in accordance with the present invention, as illustrated in FIG. 4, only two inter connecting signal lines are needed between the electronic subsystem and the printing array: a video clock or strobe clock signal 68, and a video serial data line 70, for conveying the image or document data in serial form from the electronic subsystem 60 to the printing array 62. Logic circuitry 72 translates the clock and video data to modulate 2550 printing probes on the printer array by successively presenting groups of 64 data bits while strobing through 40 strobe signals in time synchronism, and thus is able to print a full line of data in a very short time interval on the receptor. The logic circuitry 72 is readily wire bonded to the glass substrate, and interconnects directly with thin-film transistors thereon to modulate output probes 66.
It should be noted that preferably the printing array or head maybe floating at approximately 1200 volts dc and that the translation of the serial data from the electronic subsystem to the printing array is at a very high speed. In such a system, only two lines need be isolated between the electronic subsystem 60 and the printer array 62 with the present invention (where the array must be biased at high potential for performance). In this case, it may be convenient to provide "opto-isolator" circuits 74 and 76. It should also be noted that instead of wire bonding the logic circuit generally represented, in part or in whole by block 72 to connect to the amorphous silicon thin film transistors on the glass substrate, the logic circuitry could be etched directly on glass along with the thin film transistors, as part of a custom integrated circuit using very large scale integration techniques, according to current and emerging advances in the art of thin film and gate array technology.
With reference to FIG. 5 and FIGS. 6A and 6B, there is shown in more detail a block diagram and timing of data translation logic circuitry 72 shown in FIG. 4. In particular, the video clock signal 68 is received by opto isolator 74, and simultaneously the video data signal 70 is received by another opto isolator 76, where isolators 74 and 76 are provided for the purpose of electrically disconnecting the image pattern outputting means 62 from the image-data production, processing, and storage means, i.e. the electronic subsystem 60. In this manner, 62 may be operated at electrical potential level much different from that of 60, as may be required.
The clock output signal from isolator 74 is substantially unmodified, except translated voltage-wise to the potential reference level of the print array 62, and is conveyed to a count-divider circuit 78, to an initialization and image-line synchronization circuitry 80, to the serial clocking input of a data-receiving shift register 84 (but slightly delayed by delaying means for appropriate timing synchronization with received data); and also to a derived control signal generation element, flip-flop 82. Further, the output of divider circuit 78, which is a less-frequently generated clocking signal, clock÷"n" (according to the desired divided-count number, "n", but time-aligned with the "nth" received clock signal, and successively the last of each repeating groups of "n" clocks thereafter) is presented to the serial clocking input of strobe-generating shift register, 85, and additionally to the latch enable input to the strobe output latches (with appropriate delay, or alternatively, these may be left in the "transparent", or "feed-through" state if so configured), within 85. Also, the output from 78 performs as clocking of a strobe-generation control element, flip flop 92, as well as previously described flip flop 82 (with appropriate edge delaying buffering elements). The output from 82 is a data-latch enable pulse signal 86 which captures "on-the-fly", (within a single clock cycle), the "n" last shifted data bits in the data latch, within 84, where they are retained and presented on data output lines D1 through D "n" while the successively next "n" data bits are being shifted into the data-shift register within 84. (The primary function of block 82 is to precisely time and contour the clock÷"n" waveform according to the timing requirements within device 84.)
Additionally, strobe generation control element 92 serves as an intialization means, data alignment means, and output data line synchronization/resynchronization means, by determining the initial position of the active strobe line, and it also ensures in the exemplary embodiment, that only one-of "m" strobe output lines from 85 is active at any time. The output state of 92, the strobe setup signal 87, is established (as true) via signals from the initialize and line synchronization circuit 80, or wraparound feedback from strobe output "m+1" (either of which drive 87 high), and disestablished (as false) upon receipt of the next received clock÷"n" pulse. The signal 87 is received by 85, wherein output strobe 1 is clocked high initially with the same clock÷"n" pulse, and thereafter, for each successively received clock÷"n" pulse, the single high state is shifted and presented at the next strobe output, repeatedly for "m" strobes, reflecting the completion of a full line of video data. This process may be repeated any number of times, representing such number of lines of video data as may be desirably presented to the print array or output device.
It should be understood that the present disclosure has been made only by way of example and that numerous changes of details of instruction of dimension, of operating rate, of timing, and the combination and arrangement of parts may be resorted to without departing from the true spirit and scope of the invention as hereinafter claimed.
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A fluid jet assisted electrographic marking apparatus for placing electrostatic charges upon a receptor surface in an imagewise pattern by converting high speed serial data into real time parallel applied data including means for supplying a transport fluid, a housing including an upstream ion generation region and a downstream ion modulation region, the housing including inlet means for receiving transport fluid from the means for supplying located upstream of said ion generation region, ion modulation means located at the ion modulation region, an outlet means from which transport fluid exits the housing, said ion modulation means including charged storage means having electrically conductive electrodes positioned adjacent the path of the transport fluid in the ion modulation region for controlling the passage of ions out of said housing, and a data translator for converting the serial data into real time parallel applied data, the charge storage means and the electrodes being integrally fabricated upon a substrate, the data translator being wire bonded or fabricated upon or otherwise integrally connected upon and to the substrate.
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CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of provisional patent application, Ser. No. 60/663,305, filed on Mar. 18, 2005.
BACKGROUND OF THE INVENTION
Balancing hoists have long been known in which a drum has a length of cable wound and unwound thereon as the drum is rotated in either direction to position a load held by the cable. This arrangement has utilized pneumatically operated hoists which use regulated air pressure acting on a piston to cause cable wind up or pay out by rotation of the drum. See U.S. Pat. No. 3,428,298 for a detailed description of this type of hoist. The load can be raised or lowered by the operator by exerting a low level force on the suspended load which increases or decreases the air pressure acting on the piston slightly, which pressure change is made up by a regulator to lower or raise the load accordingly.
The limited stroke of the piston limits the cable travel that can be obtained, and thus electrical motor driven balancer hoist have been developed, as described in U.S. Pat. Nos. 3,921,959 and 4,807,767.
The servo motor typically drives a planetary reduction gear, the output of which drives the cable wind up drum.
Since the cable is elastically stretchable to a significant degree, it has considerable stored energy when heavily loaded.
If the cable breaks, a hazard can be created by whipping of the cable caused by release of the stored energy when the cable breaks or when there is some other failure. Emergency brakes have been employed to prevent rapid unwinding of the cable in this situation.
The mass of the planetary gearing also increases the momentum of the movable components when winding or unwinding is underway. The control of the servo motor is made more complicated by the cable stretch and the momentum of the rotating components, creating complex dynamics, particularly at the high speeds which the electric servo motor drive systems operate.
The cable must always be maintained in tension during raising and lowering operation of the hoist in order to avoid loose turns in the cable windings on the drum leading to tangling of the windings, interfering with later unwinding. Sensors and complicated software are required to insure that this does not occur.
Thus, the use of a chain in balancing hoists would be preferable to eliminate difficulties in winding of a cable and the hazards associated with cable stretching. The use of a chain in a balancer hoist is shown in U.S. Pat. No. 3,921,959. However, the mass of a chain wound on a drum is relatively great, and when combined with the mass of a planetary gear set, this affects the response of an electric motor driven balancer hoist.
In some electric motor driven balancer hoists, load sensors sense a change in the load on the cable or chain to cause the electric motor to drive a drum to raise or lower the cable or chain balance a load in “float” mode.
The weight of an operator's hand can upset the “float” balance, since the load sensor will react to removal of the operator's hand from the handle.
Alternatively, manipulation of a handle or grip connected to the cable causes the motor to selectively drive the motor so as to raise or lower the load at a rate proportional to an up or down force applied by the operator to the grip.
Automatic controls can also execute raising or lowering motions to programmed stops as when repetitive motion cycles occur.
Such self balancing hoists have been mounted on trolleys traversed along an overhead aluminum rail track system. In order to assist movement of the trolleys, pulling on the cable by the operator in a given direction is sensed by a power cable angle sensor and powered driving of the trolley in that direction is created in response to sensing such cable pull. The cable angle sensor would be problematic with a chain, and has other limitations.
Also, trolleys have in the past been driven by friction wheels engaging a smooth surface on the aluminum rail. However, friction wheel slippage can sometimes occur especially under heavy loads, which slippage upsets the accurate functioning of the control system, as a commanded movement of the trolley may not occur if such slippage is encountered. A hoist utilizing a chain wound up on a drum would be especially troublesome.
It may be desirable to alternatively allow a free wheeling manually induced movement of the trolley, which has not heretofore been provided in a powered trolley system.
Another application of pneumatic balancing hoists is the combining of two such hoists to lift a common load by synchronizing the motion of the two cables as described in U.S. Pat. No. 5,593,138. Again, the problems of improper cable winding may encountered with a lift cable and lift travel is limited by the relative short piston strokes as a practical matter.
It is an object of the present invention to provide an electrically powered balancer hoist using a chain which has a minimum mass of the components rotated by the electrical motor to allow the use of a chain while still providing good performance.
It is a further object of the present invention to provide an electric motor drive chain hoist with an automatic float mode as well as manual mode using a handle grip in which the operator's hand on the handle does not affect the float mode.
It is another object of the present invention which incorporates powered, sensor controlled trolley movement which is accurate and more reliable, and selectively allows free wheeling of the trolley.
It is a further object to provide a double hoist system using a servo motor drive and hoist chain lift.
SUMMARY OF THE INVENTION
The present invention comprises improvement to a hoist which utilizes a chain to support the load, the chain positively driven by an electric servo motor through a low mass self locking worm gear drive which holds the supported load whenever the motor is denergized. The chain is not wound up onto a drum but driven linearly by a positive rotary drive hub, the chain optionally able to be routed into a collection receptacle. The use of a hoist chain eliminates the stored energy problem of cable hoists, as a chain does not stretch appreciably compared to a cable, and the low mass of a worm gear drive minimizes the momentum of the rotated components to provide high performance of the balancer function. This avoids the disadvantages of a cable hoist, such as the need for sophisticated control over winding and unwinding of a flexible cable on a drum, the hazards of stored energy in a stretched cable, and the other disadvantages described.
Two load sensors are used in the hoist up-down control, held in a control box supported on the lower end of the chain. The # 1 load cell is connected between separate upper and lower load shafts passing through the control box, the lower load shaft connected to the load hook or eye to generate signals corresponding to the weight of the load signals these used to drive the load up or down when the operator directly pulls up or presses down on the load attached to the hook or eye.
The # 2 load sensor is used when the hoist control system is switched to a manual control as by activation of a push button switch on the control box. A handle grip is mounted to be slidable on the lower load shaft and connected via the # 2 load sensor to the upper load shaft. The # 2 load sensor creates signals in response to up or down pressure exerted on the control grip by the user causing up or down hoist operation in correspondence to up or down force applied to the grip. Forces applied to the grip do not affect the # 1 load sensor since the # 1 load sensor is connected below the upper connection point of the # 2 load sensor support, and since the handle is slidable on the lower load shaft so as to prevent any possible effects on the system if the grip is held or released when the hoist controls are set to the balance mode.
To improve performance of the trolley drive system, steel gear rack sections are clamped onto standard overhead rails and engaged with a pinion gear driven by electric motor powered tractor carriage connected to a hoist trolley. This creates a positive drive for powered positioning of the hoist trolley along an overhead rail;
The pinion gear reaction pushes an engaged gear rack more tightly against the rail surface to insure retention of the gear rack on the overhead rail.
The pinion gear is mounted on the tractor carriage which is connected to the hoist trolley which is supported on wheels on the rail for rolling movement along the rail. The hoist assembly is supported on the trolley so as to allow relative movement thereon. The hoist assembly is connected to the tractor carriage by a load sensor which senses the force developed when an operator pulls on the hoist chain to provide a control signal such that the hoist is automatically pulled horizontally in the direction desired by the operator by controlled activation of the drive motor. A two axis sensor allows movement in a second orthogonal direction.
In an alternate embodiment, the pinion can be declutched to allow free movement of the trolley, and an encoder is provided to keep track of the trolley movement during free movement thereof.
A tandem combination of two hoists is created by connecting two chain sprockets to the worm wheel of each drive to insure synchronized rotation of both chain drive motors.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a pictorial view of a hoist system and supporting modified overhead according to the present invention.
FIG. 2 is an enlarged pictorial view of a hoist upper assembly and trolley tractor drive components included in the hoist system shown in FIG. 1 and a portion of an associated overhead rail.
FIG. 2A is a pictorial view of modified form of the trolley tractor drive components.
FIG. 3 is a further enlarged pictorial view of certain components of the upper hoist assembly shown in FIG. 2 .
FIG. 3A is an enlarged pictorial view of the chain drive hub shown in FIG. 3 .
FIG. 4 is an enlarged pictorial view of the control box and manual control grip included in the hoist system shown in FIG. 1 .
FIG. 5 is an enlarged pictorial view of some of the internal components of the control box and grip shown in FIG. 4 .
FIG. 6 is an enlarged pictorial view of an overhead track section and attached gear rack for the hoist trolley drive shown in FIGS. 1 and 2 .
FIG. 7 is a pictorial view of a stationary dual hoist system according to the invention.
FIG. 8 is a pictorial view of the major internal components of the dual hoist system shown in FIG. 7 .
FIG. 9 is a diagram of a two axis sensor arrangement for a traversing hoist system.
FIG. 9A is rotated pictorial view of the two axis sensor arrangement shown in FIG. 9 .
FIG. 9B is a fragmentary portion of the two axis sensor shown in FIGS. 9 and 9A .
FIG. 9C is a pictorial view of the two axis sensor and associated hoist assembly components.
FIG. 10 is a diagrammatic representation of a cross rail arrangement enabling movement of the rail in an orthogonal direction to the rail.
FIG. 11 is a pictorial view of a hoist assembly incorporating the two axis sensor of FIG. 9 .
DETAILED DESCRIPTION
In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims.
Referring to the drawings and particularly FIG. 1 , a hoist system 10 according to the present invention includes an upper hoist assembly 12 supported on a trolley 14 able to be traversed along an overhead rail 16 by a trolley tractor drive 18 pulling its upper hoist assembly 12 when activated.
A hoist chain 20 is driven up and down by a chain drive arrangement in the upper hoist assembly 12 , described below. The hoist chain 20 is connected to a lifting eye 22 on which the load 24 is hung.
A control grip 28 extends below the control box 26 .
Two alternately selected basic control modes may be provided. In the first mode, a “float” mode may be provided in which the weight of the load is held stationary and up or down movement of the load 24 is produced by lifting or downwardly pushing on the load 24 itself to cause up or down driving of the chain 20 to raise or lower the load 24 in response to the forces applied to the load 24 .
In the second or manual mode, upward pulling or downward pushing on the grip 28 caused up or down driving of the hoist chain 20 and thus of the load 24 at a rate and in a direction corresponding to the magnitude and direction of the forces exerted on the load 24 or grip 28 .
The signals generated by components in the control box 26 are transmitted to the hoist controls 29 , which may be comprised of a suitably programmed industrial controller as is well known in the art, which in turn controls activation of the hoist motor 25 .
FIGS. 2 and 3 show further details of the upper hoist assembly 12 .
An electric servo motor 25 is enclosed within housing 23 which drives reversible right angle gearing here comprising a worm gear 30 irreversibly engaged with a worm wheel 32 , which is connected to a shaft 34 , on which is affixed a chain driving hub 36 of a commercially available type which drives the chain 20 in either direction. FIG. 3A shows the hub 36 has a series of cavities 37 A, 37 B in which successive chain links are received to create a positive driving connection to the chain 20 . The upwardly driven chain 20 can be collected in a receptacle 38 , and when downwardly driver, chain is advanced out of the receptacle 38 . Since the chain 20 is not wound up on a drum, the collected segment of the hoist chain 20 in the receptacle 38 is not driven by the motor 25 and thus its weight does not affect the performance of hoist.
It is noted, that other types of electric motors can be used, other than an electric servo motor, such as a VFD motor.
The upper hoist assembly 12 also includes a trolley support piece 40 , having linear bearings 42 affixed thereto engaged with a bearing way 44 of the trolley 14 . An upright web 46 supports two pairs of trolley wheels 48 .
The trolley wheels 48 roll along rail tracks 50 formed in the conventional overhead rail 16 .
The tractor drive carriage 18 is connected to the trolley 14 by links 52 . The tractor carriage 18 includes an electric servo motor 19 driving a pinion gear 54 by means of a worm gear 55 and worm wheel 57 engaged with a steel gear rack 56 .
The tractor carriage 18 includes a central plate 21 mounting tractor carriage wheels 48 A rolling on rail tracks 50 . The gear rack 56 is held against the underside of one of the tracks 50 of rail 16 by clamping plates 58 affixed to the side of the gear rack 56 by bolts 60 threaded into a hole in the gear rack 56 and into retainer blocks 62 in T slots in the side of the rail 16 ( FIG. 6 ). The reaction to driving by the pinion gear 54 tends to force the gear rack 56 more tightly against the underside of one track 50 of the rail 16 to be quite securely held against the same. Conventional existing aluminum rails can be quickly and easily modified in this way.
A load sensor 64 and an orthogonally arranged pair of yokes 66 , 68 interconnects the upper hoist assembly 12 to the tractor carriage 18 via limits connected to. When an operator pulls on the chain 20 in either direction, the resultant compressive or tensile load exerted on the load sensor 64 is detected, and the tractor carriage 18 is positively driven to null the signal generated by load sensor 64 to controllably move the upper hoist assembly 12 in either direction at a rate corresponding to the magnitude of the pull sensed by load sensor 64 .
The electric servo motor 19 is activated in a direction and at a rate tending to null the load sensor signals, and thus positively drive the tractor carriage 18 and upper hoist assembly 12 through worm gear 55 and worm wheel 57 along the rail 16 until the operator determines the desired location has been reached and discontinues pulling on the hoist chain 20 .
FIG. 2A shows an alternate form of the tractor drive carriage 18 A, in which an electrically operated clutch 51 interposed between the pinion 54 and the drive components 55 , 52 is included to allow free rolling of the tractor drive carriage 18 A along the rail 16 . An encoder 53 driven by a pinion gear 54 A engaging the gear rack 56 components generates signals corresponding to the linear displacement of the tractor carriage 18 A, which allows the position of the tractor drive carriage 18 A to be monitored during free motion of the carriage 18 A.
FIGS. 4 and 5 show further details concerning the control box 26 and control grip 28 . The hoist chain 20 is connected to an upper portion of a load support including a shaft 70 also connected to the top 27 of the control box 26 .
The shaft 70 is connected to a lower portion of a load support comprising a shaft 72 and lifting eye 22 by an intermediate # 1 load sensor 74 .
The lower shaft 72 is threaded to a lifting eye 22 (or hook) on which the load 24 may be hung. Thus, the load sensor 74 generates electrical signals corresponding to the weight of the load 24 . These signals are transmitted via a flexible cable assembly 70 connected by means of a suitable terminal block 23 in the control box 26 mounted to a mounting plate 76 within the control box 26 to a flex cable assembly 78 ( FIG. 1 ) leading to the upper hoist assembly 12 . A programmable industrial controller may be used for the hoist controls 29 of a well known type to cause desired preprogrammed responses to inputs from control buttons 80 A, 80 B and associated switches in the control box (not shown). An emergency stop button 82 is also provided to enable complete stoppage of the servo motor 25 .
A # 2 load sensor 84 is also provided which has an upper end connected to the upper shaft 70 via a self aligning connection 86 and has a lower end to the control grip 28 suspended from the shaft 70 via another self aligning connection 88 and bracket 90 attached to the top of the grip 28 . The control grip 28 slidably receives the lower shaft 72 which passes freely through an opening in the same as shown.
The # 2 load sensor 84 thus only senses the forces manually exerted on the control grip 28 by the operator and is uninfluenced by the weight of the load, while the # 1 load sensor 74 is not influenced by the forces exerted on the grip 28 .
Many modes of operation are possible by suitable programming of the hoist controls. The basic modes of operation includes a “float” mode, in which the weight of the load 24 is just balanced by the hoist drive. That is, lifting or pushing down on the load 24 directly, as is done in final positioning of a load, will cause the chain 20 to be driven up or down by activation of the servo motor 25 so as to allow positioning of the load 24 in that manner. This mode may be set by a programmed event, such as by pushing the lower button 80 B briefly.
A “manual” mode may be selected as by pushing the upper control button 80 A. In this mode, the hoist chain 20 will be driven up if the grip 28 is pulled up, and will be driven down if the grip 28 is pushed down, at rates corresponding to the level to the level of the force exerted on the grip 28 . The load 24 is held by the irreversible engagement of the worm gear 30 and worm wheel 32 if no force is exerted on the grip 28 .
Upper and lower limits may be optionally preset by suitable programming of the hoist controller 29 , i.e. the load 24 driven to an upper limit by controlling activation of the servo motor 25 by pulling the grip 28 upward in the manual mode, and the upper button 82 A depressed and held until a light 86 A flashes.
A lower limit is set by pushing down on the grip 28 until a desired lower limit is reached, and programmed in by holding lower control button 80 B until light 86 B flashes.
Other control features could be programmed into the controller 29 .
FIGS. 7 and 8 show a stationary double hoist according to the invention.
In this embodiment, two spaced apart hoist assemblies 88 A, 88 B are mounted on supporting column 90 connected by a cross beam 94 .
An electric servo motor 92 A, 92 B is included in each hoist assembly 88 a , 88 B driving a respective worm gear 96 A, 96 B in turn irreversibly engaged with a respective worm wheel 98 A, 98 B mounted on a respective cross shaft 100 A, 100 B.
Each cross shaft 100 A, 100 B has a chain drive hub 102 A, 102 B affixed thereto engaged with a respective one of the two hoist chains 104 A, 104 B.
A synchronizing double chain 106 A, 106 B engage both sprocket pairs 108 A, 108 B affixed to respective cross shafts 100 A, 100 B. This insures equal movements of the chains 104 A, 104 B. A chain tensioner 110 can be provided, mounted to cross beam 94 .
A pair of hanger plates 112 A, 112 B can be utilized to support the hoist assemblies 88 A, 88 B on the cross beam 94 .
A single electric motor 92 A may be used to drive both chain drive hubs 102 A, 102 B via the double chain 106 A, 106 B.
FIGS. 9-9C show a two axis chain pull sensor 114 mounted in a housing 23 .
A tube 116 is held and restrained at its upper end by a mounting comprising of two adjustable clamp collars 134 A, 134 B on either side of a bracket 136 . A clearance C is set so that the tube 116 is constrained only by load sensor rods described below when the hoist chain 20 is pulled. One axis is aligned with the rail 16 , the other in the direction of bridge rails 16 A ( FIG. 10 ) supporting the ends of the rail 16 for movement of the hoist assembly 16 along a direction normal to the rail 16 .
An anti-rotation screw 138 is threaded into the upper collar 134 A through a slot 140 in the bracket 136 .
The tube 116 receives the hoist chain 20 which passes through to the chain drive hub 36 aligned so that the chain 20 does not normally exert any pressure on the tube 116 . When the hoist chain 20 is pulled in the direction of either axis, this causes force to be applied in either direction to a respective load sensor 124 A, 124 B.
The tube 116 has a pair of spaced plates 118 which receive self aligning eye connections 120 A, B aligned along each orthogonal axis connecting a respective rod 122 A, B to load sensor 124 A, 124 B. A second rod 126 A, 126 B is held by a fixed mounting block 132 A, B receiving another self aligning pivot connection 128 A, 128 B. The signals generated by load sensors 124 A, B are sent to the hoist controls 29 which causes activation of respective tractor drives 18 A, 130 A, 130 B to drive the hoist assembly 12 along rail 16 or rails 16 A to position the hoist assembly 12 at points along either axis.
FIG. 11 shows an upper hoist assembly 12 A in which the tractor trolley drive and chain drive are both contained in the housing 23 A. the tractor drive includes a clutch-pinion gear assembly 144 driven by a servo motor (not shown in FIG. 11 ) engaged with the gear rack 56 . An encoder second pinion gear assembly 146 includes a pinion gear 54 A and encoder 53 A.
An industrial controller comprising the hoist control 29 is also shown. The chain drive includes an electric servo motor 25 driving irreversible right angle gearing unit 148 incorporating the worm gear and worm wheel (not shown in FIG. 11 ).
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A balancer hoist has an electric servomotor driving irreversible gearing in turn driving a hoist chain drive. A float mode and a manual mode are provided using two independent load sensors for sensing the load weight and force applied to a control grip. A traversing control is produced by a tractor carriage rolling on an overhead rail connected to a trolley also traveling on the rail and supported on upper hoist assembly. A load sensor interconnects the tractor carriage and upon hoist assembly to sense forces created by an operator pulling on the chain, which are used to control an electric motor on the tractor carriage driving a pinion gear engaged with a gear rack on the overhead rail to positively drive the carriage, trolley and upper hoist assembly along the rail. A stationary dual hoist system is also described in which two hoist assemblies are interconnected by a chain and sprockets to provide synchronized operation.
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CROSS-REFERENCES TO RELATED APPLICATION
This application is a division of U.S. patent application Ser. No. 13/975,639 filed on Aug. 26, 2013, which claims priority under 35 U.S.C. §119(a) to Korean application number 10-2013-0046090, filed on Apr. 25, 2013, in the Korean Intellectual Property Office. The disclosure of each of the foregoing applications is incorporated herein by reference in its entirety.
BACKGROUND
Currently, resistive memory devices using a resistance material has been suggested, and the resistive memory devices may include phase-change random access memories (PCRAMs), resistance RAMs (ReRAMs), or magentoresistive RAMs (MRAMs) has been suggested.
The resistive memory devices may include a switching device and a resistance device, and may store data “0” or “1” according to a state of the resistance device.
Even in the resistive memory devices, the first priority is to improve integration density and to integrate memory cells in a narrow area as many as possible.
Currently, the variable resistance memory device is also configured in a 3D structure, but there is a high need for a method of stably stacking a plurality of memory cells with smaller critical dimension (CD).
SUMMARY
An exemplary variable resistance memory device. The variable resistance memory device may include: a semiconductor substrate; a common source region formed on the semiconductor layer; a channel layer formed substantially perpendicular to a surface of the semiconductor substrate, the channel layer being selectively connected to the common source region; a plurality of cell gate electrodes formed along a side of the channel layer; a gate insulating layer formed around each cell gate electrode, of the plurality of cell gate electrodes, a cell drain region located between the each cell gate electrode of the plurality of cell gate electrodes; a variable resistance layer formed along another side of the channel layer; and a bit line electrically connected to the channel layer and the variable resistance layer.
An exemplary method of manufacturing a variable resistance memory device include: forming a common source line on a semiconductor substrate; forming selection switches on the common source region; forming, over the selection switches, an insulating structure on the semiconductor substrate by alternately stacking a plurality of first interlayer insulating layers, having a first etch selectivity, and a plurality of second interlayer insulating layers, having a second etch selectivity that is different than the first etch selectivity; forming through-holes in the insulating structure to expose the string selection switches; forming space portions by removing portions of the plurality of first interlayer insulating layers exposed through the through-holes; forming a cell drain region in each of the space portions; forming, in each through-hole, a channel layer along surfaces defining each through-hole; selectively removing the plurality of second insulating layers to form a plurality of openings; forming a gate insulating layer in each opening of the plurality of openings; forming a cell gate electrode in each opening, of the plurality of openings, so that each cell gate electrode is surrounded by a gate insulating layer; forming a variable resistance layer on a surface of the channel layer; forming an insulating layer in the through-holes; and forming a bit line to be electrically connected to the channel layer and the variable resistance layer.
An exemplary variable resistance memory device may include: a plurality of cell gate electrodes extending in a first direction, wherein the plurality of cell gate electrodes are stacked in a second direction that is substantially perpendicular to the first direction; a gate insulating layer surrounding each cell gate electrode of the plurality of cell gate electrodes; a cell drain region formed on two sides of the each cell gate electrode of the plurality of cell gate electrodes; a channel layer extending in the second direction along the stack of the plurality of cell gate electrodes; and a variable resistance layer contacting the channel layer.
A method of operating an exemplary variable resistance memory device, including a plurality of memory cells having a plurality of cell gate electrodes extending in a first direction, wherein the plurality of cell gate electrodes are stacked in a second direction that is substantially perpendicular to the first direction; a gate insulating layer surrounding each cell gate electrode of the plurality of cell gate electrodes; a cell drain region formed on two sides of the each cell gate electrode of the plurality of cell gate electrodes; a channel layer extending in the second direction along the stack of the plurality of cell gate electrodes; and a variable resistance layer contacting the channel layer, wherein the variable resistance memory device is in contact with a selection switch, may include: selecting a memory cell, of the plurality of memory cells, via the selection switch; passing a current from a bit line through a variable resistor of the selected memory cell to perform an operation on the selected memory cell; and passing the current through a portion of the channel layer associated with a non-selected memory cell.
These and other features, aspects, and exemplary implementations are described below in the section entitled “DETAILED DESCRIPTION”.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and other advantages of the subject matter of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a circuit diagram illustrating an exemplary variable resistance memory device;
FIG. 2 is a circuit diagram illustrating an exemplary variable resistance;
FIG. 3 is a view illustrating a driving method of an variable resistance memory device;
FIGS. 4 to 10 are cross-sectional views sequentially illustrating an exemplary method of manufacturing a variable resistance memory device;
FIG. 11 is an enlarged view illustrating an exemplary switching device of a variable resistance memory device; and
FIGS. 12 and 13 are cross-sectional views illustrating exemplary variable resistance memory devices.
DETAILED DESCRIPTION
Hereinafter, exemplary implementations will be described in greater detail with reference to the accompanying drawings.
Exemplary implementations are described herein with reference to cross-sectional illustrations that are schematic illustrations of exemplary implementations (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary implementations should not be construed as limited to the particular shapes of regions illustrated herein but may be to include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. Throughout the disclosure, reference numerals correspond directly to the like numbered parts in the various figures and implementations of the present invention. It should be readily understood that the meaning of “on” and “over” in the present disclosure should be interpreted in the broadest manner such that “on” means not only “directly on” but also “on” something with an intermediate feature(s) or a layer(s) therebetween, and that “over” means not only directly on top but also on top of something with an intermediate feature(s) or a layer(s) therebetween.
Referring to FIG. 1 , an exemplary variable resistance memory device 10 includes a plurality of memory cells mc 1 , mc 2 , mc 3 , and mc 4 , connected in series.
The plurality of memory cells mc 1 , mc 2 , mc 3 , and mc 4 , which are connected in series, may be connected between a bit line BL and a common source line CS. That is, the plurality of memory cells mc 1 , mc 2 , mc 3 , and mc 4 may be implemented by sequentially stacking the memory cells mc 1 , mc 2 , mc 3 , and mc 4 on a semiconductor substrate (not shown). In the exemplary implementation, a set of the stacked memory cells mc 1 to mc 4 , connected in series, may be referred to as a column string SS 1 and SS 2 . A plurality of column strings SS 1 and SS 2 may be connected to one bit line BL.
Each of the plurality of memory cells mc 1 to mc 4 may include a switching device SW 1 to SW 4 and a variable resistor R 1 to R 4 . The switching device SW 1 to SW 4 and the variable resistor R 1 to R 4 may be connected in parallel to each other.
A MOS transistor, a diode, a bipolar transistor, or an impact ionization MOS (IMOS) transistor may be used as the switching devices SW 1 to SW 4 . The variable resistors R 1 to R 4 may include various materials, such as a Pr1-xCaxMnO3 (PCMO) layer, if the variable resistor is a ReRAM, a chalcogenide layer, if the variable resistor is a PCRAM, a magnetic layer, if the variable resistor is a MRAM, a magnetization reversal device layer, if the variable resistor is a spin-transfer torque magnetoresistive RAM (STTMRAM), or a polymer layer, if the variable resistor is a polymer RAM (PoRAM).
A column switch array 15 may be connected between the column strings SS 1 and SS 2 and the common source line CS. The column switch array 15 may include a plurality of string selection switches SSW 1 and SSW 2 . Each of the string selection switches SSW 1 and SSW 2 may be connected to a corresponding column strings SS 1 or SS 2 . Each of the string selection switches SSW 1 or SSW 2 selectively connects a corresponding column string SS 1 or SS 2 to the common source line CS in response to a corresponding selection signal a 1 or a 2 .
FIG. 2 illustrates an alternative arrangement of the column switch array 15 , the column strings SS 1 and SS 2 , and the bit line BL.
Hereinafter, driving the exemplary variable resistance memory device will be described. As an example, a process of reading and writing data from and to a third memory cell mc 3 of a first column string SS 1 will be described.
Referring to FIG. 3 , a high voltage is applied to a gate a 1 of a first string switch SSW 1 to select the first column string SS 1 .
To write data to the third memory cell mc 3 , the switching device SW 3 of the third memory cell mc 3 is turned off, and the first switching device SW 1 of the first memory cell mc 1 , the second switching device SW 2 of second memory cell mc 2 , and the fourth switching device SW 4 of the fourth memory cells mc 4 , are turned on.
Accordingly, the fourth switching device SW 4 in the fourth memory cell mc 4 , the second switching device SW 2 in the second memory cell mc 2 , and the first switching device SW 1 in the first memory cell mc 1 , are turned on to form a current path is formed in the fourth switching device SW 4 , the second switching device SW 2 , and the first switching device SW 1 . The third switching device SW 3 in the third memory cell mc 3 is turned off, and a current path is formed in a third variable resistor R 3 .
Therefore, a write current Iw, provided from the bit line BL, flows to the common source line CS through the fourth switching device SW 4 , the third variable resistor R 3 , and the second switching device SW 2 , and first switching device SW 1 . Therefore, data may be written to the third memory cell mc 3 .
A read operation of the third memory cell mc 3 may be carried out in substantially the same manner as described above for the write operation, except that a read current Ir (instead of a write current Iw) may be provided from the bit line BL. The read current Ir reaches the common source line CS connected to a ground through a corresponding current path. The data written in the variable resistor R 3 may be sensed by measuring using read circuit (not shown) a current value reaching the common source line CS. At this time, the read current Ir has a level that does not affect a crystallization state of the variable resistor R 3 , and may have a lower value than that of the write current Iw.
Hereinafter, a exemplary method of manufacturing an exemplary variable resistance memory device will be described with reference to FIGS. 4 to 10 .
Referring to FIG. 4 , a common source region 105 is formed on a semiconductor substrate 100 . In FIG. 4 , an “X” region indicates a portion of the variable resistance memory device taken in a direction parallel to a bit line to be formed later, and a “Y” region indicates a portion of the variable resistance memory device taken in a direction perpendicular to the bit line. The common source region 105 may be configured of, for example, an impurity region or a conductive layer. A conductivity type of the common source region 105 may be determined according to a conductivity type of the string selection switches SSW 1 and SSW 2 . For example, if the string selection switches SSW 1 and SSW 2 are an MOS transistor, then the common source region 105 may be an N-type impurity region or a polysilicon layer doped with an N-type impurity.
A conductive layer having a certain thickness may be formed on the common source region 105 , and then patterned to form a plurality of pillars 110 that will form channels of the string selection switches SSW 1 and SSW 2 . The pillars 110 may include semiconductor layers, such as polysilicon layers. A drain region 115 may be formed into an upper portion of each of the pillars 110 using an impurity having the same conductivity type as the impurity of the common source region 105 .
A gate insulating layer 120 may be formed on the semiconductor substrate 100 , on which the pillars 110 are formed. A gate 125 may be formed to surround each of the pillars 110 . The gate insulating layer 120 may be formed by oxidizing the semiconductor substrate 100 , including the pillars 110 , or by depositing an oxide layer on the semiconductor substrate 100 , including the pillars 110 . The gate 125 may be formed to a height (or a thickness) corresponding to the channel formation region (a region between the drain region and the common source region). Therefore, the string selection switches SSW 1 and SSW 2 , having vertical structures, are completed.
An insulating layer 130 may be formed to cover the semiconductor substrate 100 , on which the string selection switches SSW 1 and SSW 2 are formed. The insulating layer 130 may have a thickness sufficient to bury the string selection switches SSW 1 and SSW 2 . The insulating layer 130 may be planarized to expose the drain region 115 . An ohmic layer 135 may be formed in the exposed drain region 115 via a conventional process. The ohmic layer 135 may be, for example, a silicide.
Referring to FIG. 5 , first interlayer insulating layers 140 a , 140 b , 140 c , 140 d , and 140 e and second interlayer insulating layers 145 a , 145 b , 145 c , and 145 d are alternately formed on the insulating layer 130 to form an insulating structure. For example, first interlayer insulating layer 140 e may be located in the uppermost layer of the insulating structure. The first interlayer insulating layers 140 a , 140 b , 140 c , 140 d , and 140 e may have an etch selectivity that is different than an etch selectivity of the second interlayer insulating layers 145 a , 145 b , 145 c , 145 d , and 145 e.
As illustrated in FIG. 6 , a certain portion of the insulating structure is etched to form a through-hole 150 exposing the ohmic layer 135 . Certain portions of the first interlayer insulating layers 140 a , 140 b , 140 c , 140 d , and 140 e , which are exposed through the through-hole 150 , may be are removed by, for example, a wet etch method. Therefore, the etched first interlayer insulating layers 140 a , 140 b , 140 c , 140 d , and 140 e are narrower than the second interlayer insulating layers 145 a , 145 b , 145 c , and 145 d.
Drain regions 155 of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 are formed in spaces from which the first interlayer insulating layers 140 a , 140 b , 140 c , 140 d , and 140 e are removed. Therefore, the drain regions of the switching devices are exposed through a sidewall of the through-hole 150 .
The drain regions 155 may include, for example, a semiconductor layer, such as a silicon (Si) layer, a silicon germanium (SiGe) layer, a gallium arsenide (GaAs) layer, or a doped polysilicon layer, or a metal layer, such as tungsten (W), copper (Cu), titanium nitride (TIN), tantalum nitride (TaN), tungsten nitride (WN), molybdenum nitride (MoN), niobium nitride (NbN), titanium silicon nitride (TiSiN), titanium aluminum nitride (TiAlN), titanium boron nitride (TiBN), zirconium silicon nitride (ZrSiN), tungsten silicon nitride (WSiN), tungsten boron nitride (WBN), zirconium aluminum nitride (ZrAlN), molybdenum silicon nitride (MoSiN), molybdenum aluminum nitride (MoAlN), tantalum silicon nitride (TaSiN), tantalum aluminum nitride (TaAlN), titanium (Ti), molybdenum (Mo), tantalum (Ta), titanium silicide (TiSi), tantalum silicide (TaSi), titanium tungsten (TiW), titanium oxynitride (TiON), titanium aluminum oxynitride (TiAlON), tungsten oxynitride (WON), or tantalum oxynitride (TaON).
Referring to FIG. 7 , a channel layer 160 is formed along a surface defining the through-hole 150 . The channel layer 160 may include a conductive semiconductor layer, such as an impurity doped semiconductor layer. The channel layer 160 may have a conductivity type that is opposite to the conductivity type of the drain regions 155 . A first buried insulating layer 165 is formed in the through-hole 150 , over the channel layer 160 . At this time, the first buried insulating layer 165 may be provided to prevent the channel layer 160 from being lost when the first and second separation holes are formed.
Referring to FIG. 8 , a first separation hole H 1 for node separation is formed in a space between through-holes 150 to separate adjacent nodes. The first separation hole H 1 may be formed in the insulating structure between the string selection switches SSW 1 and SSW 2 . The second interlayer insulating layers 145 a , 145 b , 145 c , and 145 d , which are exposed through the first separation hole H 1 , are removed to form second separation holes H 2 . Since the first interlayer insulating layers 140 a , 140 b , 140 c , 140 d , and 140 e have an etch selectivity that is different than an etch selectivity of the second interlayer insulating layers 145 a , 145 b , 145 c , and 145 d , only the second interlayer insulating layers 145 a , 145 b , 145 c , and 145 d may be selectively removed. Therefore, the first separation holes H 1 are substantially perpendicular to a surface of the semiconductor substrate 100 , and the second separation holes H 2 are substantially parallel to the surface of the semiconductor substrate 100 .
Referring to FIG. 9 , a gate insulating layer 170 is formed on a surface defining each of the second separation holes H 2 . A gate electrode 175 is formed within each of the second separation holes H 2 . The gate insulating layer 170 may include, for example, silicon oxide or silicon nitride, or an oxide or a nitride of a metal, such as Ta, Ti, barium titanate (BaTi), barium zirconium (BaZr), zirconium (Zr), hafnium (Hf), lanthanum (La), aluminum (Al), or zirconium silicide (ZrSi). The gate electrode 175 may include a semiconductor layer, such as, for example, a Si layer, a SiGe layer, or an impurity doped GaAs layer, or a metal-containing layer, such as, for example, W, Cu, TiN, TaN, WN, MoN, NbN, TiSiN, TiAlN, TiBN, ZrSiN, WSiN, WBN, ZrAlN, MoSiN, MoAlN, TaSiN, TaAlN, Ti, Mo, Ta, Tisi, TaSi, TiW, TiON, TiAlON, WON, or TaON. Next, a second buried insulating layer 178 may be formed the first separation hole H 1 . The second buried insulating layer 178 may include a layer having an etch selectivity that is different than an etch selectivity of the first buried insulating layer 165 .
Referring to FIG. 10 , the first buried insulating layer 165 buried in the through-hole 150 may be selectively removed to expose the channel layer 160 . A variable resistance layer 180 is deposited on an exposed surface of the channel layer 180 . The variable resistance layer 180 may include various materials, such as a Pr1-xCaxMnO3 (PCMO) layer, if the variable resistor is a ReRAM, a chalcogenide layer, if the variable resistor is a PCRAM, a magnetic layer, if the variable resistor is a MRAM, a magnetization reversal device layer, if the variable resistor is a spin-transfer torque magnetoresistive RAM (STTMRAM), or a polymer layer, if the variable resistor is a polymer RAM (PoRAM). At this time, current characteristic of the device may be controlled according to control of a thickness of the variable resistance layer 180 .
A third buried insulating layer 185 may be formed within the through-hole 150 , over the variable resistance layer 180 . Next, a bit line 190 is formed to be in contact with the channel layer 160 and the variable resistance layer 180 and therefore, the variable resistance memory device having a stacked structure is completed.
As illustrated in FIG. 11 , in the resistance memory cell, the drain regions 155 are located adjacent to the gate electrodes 175 , and the channel layer 160 and the variable resistance layer 180 are located adjacent to the drain regions. Therefore, when current is provided from the bit line 190 , current selectively flows along the channel layer 160 or the variable resistance layer 180 according to an on/off condition of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 .
Thus, effective channel lengths (see EC 1 of FIG. 11 ) of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 in the exemplary implementation may be substantially increased as compared with an effective channel length (see EC 2 of FIG. 11 ) of a conventional 3D switching device. Therefore, switching characteristics of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 may be improved without increasing a size of the switching devices SW 1 , SW 2 , SW 3 , and SW 4 .
FIG. 12 shown an alternative exemplary implementation that lacks the first separation holes H 1 (as shown in FIG. 8 ). In this exemplary implementation, the same voltage may be provided to gate electrodes 175 located in the same layer. This structure may be formed by selectively removing second interlayer insulating layers 145 a , 145 b , 145 c , and 145 d without the forming of the first separation hole H 1 .
As illustrated in FIG. 13 , a channel layer 160 a may be formed on only a portion of a sidewall that defines a through-hole (see 150 of FIG. 6 ) that faces each of the gate electrodes 175 . That is, since drain regions 155 are located below and on gate electrodes 175 , the channel layer 160 a may not affect the operation of the device even when the channel layer 160 a is located in a overlapping region of the gate electrode 175 and the through-hole.
The above exemplary implementations are illustrative and not limitative. Various alternatives and equivalents are possible. The invention is not limited by the exemplary implementations described herein. Nor is the invention limited to any specific type of semiconductor device. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.
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A variable resistance memory device includes a plurality of cell gate electrodes extending in a first direction, wherein the plurality of cell gate electrodes are stacked in a second direction that is substantially perpendicular to the first direction. A gate insulating layer surrounds each cell gate electrode of the plurality of cell gate electrodes and a cell drain region is formed on two sides of the each cell gate electrode of the plurality of cell gate electrodes. A channel layer extends in the second direction along the stack of the plurality of cell gate electrodes, and a variable resistance layer contacting the channel layer.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims benefit of priority from U.S. Provisional Application No. 61/285,425 filed Dec. 10, 2009.
FIELD OF THE INVENTION
[0002] The invention relates to soil repellency aqueous dispersions comprising a colloidal dispersion of clay nanoparticles and an aqueous fluorochemical. Soil repellant soft articles that have been modified by the soil repellency aqueous dispersions, which result in having improved anti-soil properties, are also disclosed. The soft articles can comprise fibers, yarns, and textiles. Also disclosed herein are processes for making the soil repellency aqueous dispersions and soil repellant soft articles.
BACKGROUND OF THE TECHNOLOGY
[0003] Sub-micron particles of inorganic oxides (i.e. silica) have been applied topically to polyamide fibers in the past to provide anti-soil deposition benefits, but have suffered from poor durability and harsh texture. Additionally, the silica treated surfaces can have an unappealing white haze at certain deposition concentrations. Fluorochemical resin emulsions have been used to create low soiling soft surfaces.
[0004] U.S. Pat. No. 6,225,403 teaches the use of surface treating compositions comprised of a blend of fluorochemical resins with colloidal sol dispersions of organosiloxane co-polymers. This blend allows for significantly reduced add-on levels of fluorochemicals on soft-surfaces to achieve acceptable soil repellency. However, these colloidal siloxane fluorine extenders can impart a harsh feel to the soft surface which is undesirable.
SUMMARY OF THE INVENTION
[0005] There is a desire to reduce the overall usage of fluorochemicals for environmental and cost reasons. Thus, it can be understood that soil repellency compositions that reduce the amount of fluorochemicals used, but still retain good soil-resistance, are in demand.
[0006] Therefore, it is desirable to further extend the effectiveness of fluorochemicals and to produce a softer hand fiber while retaining desirable soil-resistant attributes.
[0007] The invention disclosed herein provides soil repellency aqueous dispersions comprising aqueous dispersions of clay nanoparticles that can be combined with traditional fluorochemicals. The clay nanoparticles can be added to anti-soil formulations and water/oil repellant formulations. Fibers treated with the disclosed dispersions show superior anti-soil deposition and dry soil repellency properties over prior fluorochemical and silicone treated fibers. Treated fibers also show softer hand feel and better durability over prior fluorochemical or silicone treated fibers. The nanoparticles are shown to act as a fluorochemical extender allowing anti-soiling properties on the fiber at reduced fluorine levels on the weight of fiber. Also provided are methods of making the disclosed aqueous dispersions and treated fibers. Further provided are yarns and textiles, such as fabrics and carpets, made with various aspects of the treated fibers.
[0008] Clay nanoparticles can be effective diluents for fluorochemicals in fluorochemical water and oil repellency treatment compositions directed to fibrous soft surfaces. Specifically, the amount of fluorochemical required for a given anti-soil effect is surprisingly reduced by inclusion of clay nanoparticles in the fluorochemical formulation or emulsion, resulting in effective soil repellency at substantially reduced fluorine levels compared to the prior formulations. When fibers are treated with the disclosed aqueous dispersions, the clay particles are essentially hydrophilic but are still effective as extenders of the hydrophobic properties that would otherwise be expected to depend on the fluorochemical concentration alone. Under certain conditions, aqueous dispersions of clay nanoparticles are shown to impart many of the same benefits expected from fluorochemicals alone.
[0009] In one aspect, an aqueous dispersion for soil repellency comprising at least one clay nanoparticle component and a fluorochemical is provided. The clay nanoparticle component can be either natural or synthetic. The fluorochemical can comprise any chemical containing a carbon-fluorine moiety.
[0010] In another aspect, a fiber comprising a surface treatment comprising at least one clay nanoparticle component and a fluorochemical is provided. The fiber can be any natural or synthetic fiber, including cotton, silk, wool, rayon, polyamide, acetate, olefin, acrylic, polypropylene, and polyester. The fiber can be spun into a yarn or manufactured into a textile.
[0011] In a further aspect, a textile comprising at least one fiber treated with a soil repellency aqueous dispersion comprising at least one clay nanoparticle component and a fluorochemical is provided. The textile can be any woven fabric or carpet. The carpet can include cut pile, twisted, woven, needlefelt, knotted, tufted, flatweave, frieze, berber, and loop pile.
[0012] In yet another aspect, a process of making a soil repellency aqueous dispersion is provided. Such process comprises contacting at least one clay nanoparticle component with a solvent to form an aqueous clay nanoparticle solution, and contacting said aqueous clay nanoparticle solution with a fluorochemical to form the soil repellency aqueous dispersions.
[0013] In yet a further aspect, a process of making a soil repellant fiber using soil repellency aqueous dispersions discussed above is provided. Such process comprises applying said aqueous dispersions onto said fiber in an amount resulting in said at least one clay nanoparticle component present in an amount from about 200 ppm (parts per million-particle weight per weight of the fiber) to about 4000 ppm OWF, including from about 500 ppm to about 1500 ppm OWF, from about 500 ppm to about 1000 ppm OWF, from about 1000 ppm to about 1500 ppm, from about 1000 ppm to about 2000 ppm OWF, and from about 1500 ppm to about 2000 ppm OWF, on the surface of the fiber; and said fluorochemical present in an amount that results in an elemental fluorine content of from about 25 ppm to about 1000 ppm OWF, including from about 25 to about 500 ppm OWF, from about 75 ppm to about 150 ppm OWF, from about 75 ppm to about 200 ppm OWF, from about 100 ppm to about 200 ppm OWF, and from about 140 ppm to about 150 ppm OWF, on the surface of said fiber. The fiber is then cured. (Curing refers to the process of drying the solvent used to carry the solution onto the fiber. This can optionally be done using a heating step.) The same process can be applied to yarns and textiles.
DEFINITIONS
[0014] While mostly familiar to those versed in the art, the following definitions are provided in the interest of clarity.
[0015] Nanoparticle: A multidimensional particle in which one of its dimensions is less than 100 nm in length.
[0016] OWF (On weight of fiber): The amount of solids that were applied after drying off the solvent.
[0017] WPU (Wet Pick-up): The amount of solution weight that was applied to the fiber before drying off the solvent.
DETAILED DESCRIPTION OF THE INVENTION
[0018] A soil repellency aqueous dispersion is disclosed comprising at least one clay nanoparticle component and a fluorochemical. The clay nanoparticle component can refer to particles substantially comprising minerals of the following geological classes: smectites, kaolins, illites, chlorites, and attapulgites. These classes include specific clays such as montmorillonite, bentonite, pyrophyllite, hectorite, saponite, sauconite, nontronite, talc, beidellite, volchonskoite, vermiculite, kaolinite, dickite, antigorite, anauxite, indellite, chrysotile, bravaisite, suscovite, paragonite, biotite, corrensite, penninite, donbassite, sudoite, pennine, sepiolite, and polygorskyte. The clay nanoparticles can be either synthetic or natural, including synthetic hectorite, and Laponite® from Rockwood Additives Ltd. The Laponite® clay nanoparticles can be Laponite RD®, Laponite RDS®, Laponite JS®, and Laponite S482®.
[0019] The fluorochemicals can include any liquid containing at least one dispersed or emulsified fluorine containing polymer or oligomer. The liquid can also contain other non-fluorine containing compounds. Examples of fluorochemical compositions used in the disclosed composition include anionic, cationic, or nonionic fluorochemicals such as the fluorochemical allophanates disclosed in U.S. Pat. No. 4,606,737; fluorochemical polyacrylates disclosed in U.S. Pat. Nos. 3,574,791 and 4,147,85; fluorochemical urethanes disclosed in U.S. Pat. No. 3,398,182; fluorochemical carbodiimides disclosed in U.S. Pat. No. 4,024,178; and fluorochemical guanidines disclosed in U.S. Pat. No. 4,540,497. The above listed patents are hereby incorporated by reference in their entirety. A short chain fluorochemical with less than or equal to six fluorinated carbons per fluorinated side-chain bound to the active ingredient polymer or surfactant can also be used. The short chain fluorochemicals can be made using fluorotelomer raw materials or by electrochemical fluorination. Another fluorochemical that can be used in the disclosed composition is a fluorochemical emulsion sold as Capstone RCP® from DuPont.
[0020] The disclosed soil repellency aqueous dispersion can be made using various techniques. One technique comprises contacting at least one clay nanoparticle component with water to form an aqueous clay nanoparticle solution. Aqueous solvent mixtures containing low molecular weight alcohols (such as methanol, ethanol, isopropanol, and the like) can also be used to disperse the clay. The clay nanoparticle component can be present in an amount from about 0.01% to about 25% weight in solution, including about 1% to about 20%, about 0.05% to about 15%, about 0.01% to about 5%, about 0.05% to about 5%, about 0.5% to about 5%, and about 5% to about 15%. When Laponite® is used as the clay nanoparticle, the concentration is from about 0.05% to about 25% weight in solution, including from about 0.05% to 1% w/w and from about 5% to about 15% w/w. The aqueous clay nanoparticle solution is then contacted with a fluorochemical to form the soil repellency aqueous dispersion. The % elemental fluorine in the combined dispersion can be present in an amount from about 0.0001% to about 5% weight fluorine atoms present in dispersion, including about 0.001% to about 2%, about 0.001% to about 0.8%, about 0.005% to about 0.5%, about 0.005% to about 0.15%, about 0.01% to about 1%, about 0.025% to about 0.5%, and about 0.05% to about 0.5%. When Capstone RCP® is used as the fluorochemical, the concentration is from about 0.005% to about 0.5%, including from about 0.005% to about 0.15% depending on the wet pick-up percentage of the application to the fibers. When formulating the aqueous dispersions, the weight percent of clay nanoparticle component should remain higher than the weight percent fluorine. Typical weight percent ratios of clay nanoparticles to fluorine range from about 5000:1 to about 2:1, including about 3000:1, about 1500:1, about 1000:1, about 500:1, about 100:1, about 50:1, about 25:1, and about 10:1.
[0021] The disclosed soil repellency aqueous dispersion can be applied to various types of fibers as a surface treatment. The fiber can be any natural or synthetic fiber, including cotton, silk, wool, rayon, polyamide, acetate, olefin, acrylic, polypropylene, and polyester. The fiber can also be polyhexamethylene adipamide, polycaprolactam, Nylon 6,6 or Nylon 6. The fibers can be spun into yarns or woven into various textiles. Yarns can include low oriented yarn, partially oriented yarn, fully drawn yarn, flat drawn yarn, draw textured yarn, air-jet textured yarn, bulked continuous filament yarn, and spun staple. Textiles can include carpets and fabrics, wherein carpets can include cut pile, twisted, woven, needlefelt, knotted, tufted, flatweave, frieze, berber, and loop pile. Alternatively, the disclosed soil repellency aqueous dispersions can be applied to a yarn or textile, instead of the fiber.
[0022] The disclosed soil repellency aqueous dispersions can be applied to a fiber using various techniques known in the art. Such techniques include spraying, dipping, coating, foaming, painting, brushing, and rolling the soil repellency aqueous dispersion on to the fiber. The soil repellency aqueous dispersions can also be applied on the yarn spun from the fiber or a textile made from the fiber. After application, the fiber, yarn, or textile is than heat cured at a temperature of from about 25° C. to about 200° C., including from about 150° C. to about 160° C.; and a time of from about 10 seconds to about 40 minutes, including 5 minutes.
[0023] Once applied, the clay nanoparticle component can be present in an amount from about 200 ppm to about 4000 ppm OWF, including from about 500 ppm to about 1500 ppm OWF, from about 500 ppm to about 1000 ppm OWF, from about 1000 ppm to about 1500 ppm OWF, from about 1000 ppm to about 2000 ppm OWF and from about 1500 ppm to about 2000 ppm OWF, on the surface of the fiber, yarn or textile. The fluorochemical can also be present in an amount that results in an elemental fluorine content of from about 25 ppm to about 1000 ppm OWF, including from about 25 ppm to about 500 ppm OWF, from about 75 ppm to about 150 ppm OWF, from about 75 ppm to about 200 ppm OWF, from about 100 ppm to about 200 ppm OWF, and from about 140 ppm to about 150 ppm OWF, on the surface of the fiber, yarn or textile. When applying the aqueous dispersions, the OWF of the clay nanoparticle component should remain higher than the OWF of fluorine. Typical OWF ratios of nanoparticles to fluorine can range from about 80:1 to about 1.5:1, including about 27:1, about 20:1, about 13:1, about 10:1, about 7.5:1, and about 5:1. Fibers, yarns, and textiles with these surface concentrations have a Delta E of from about 15 to about 23 when measured using ASTM D6540.
[0024] Additional components can be added to the soil repellency composition disclosed above. Such components can include silicones, optical brighteners, antibacterial components, anti-oxidant stabilizers, coloring agents, light stabilizers, UV absorbers, base dyes, and acid dyes. Optical brighteners can include a triazine type, a coumarin type, a benzoxaxole type, a stilbene type, and 2,2′-(1,2-ethenediyldi-4,1 phenylene)bisbenzoxazole, where the brightener is present in an amount by weight of total composition from about 0.005% to about 0.2%. Antimicrobial components can include silver containing compounds, where the antimicrobial component is present in an amount by weight of total composition from about 2 ppm to about 1%.
[0025] The nanoparticles are shown to act as a fluorochemical extender allowing anti-soiling properties on the fiber at reduced fluorine levels on the weight of fiber.
Examples
[0026] The following are examples of Nylon 6,6 46 ounce cut-pile carpet treated with the soil repellency aqueous dispersions disclosed above compared to a standard fluorochemical emulsion treatment (comparative), and no treatment. Selection of alternative fluorochemicals, clay nanoparticles, fibers and textiles having different surface chemistries will necessitate minor adjustments to the variables herein described.
Test Methods
[0027] Drum soiling is recorded as Delta E and measured according to ASTM D6540 and D1776.
[0028] Table 1, below, lists the various carpet samples: (1) treated with the various aspects of the disclosed soil repellency composition (Samples 1-12); (2) treated with a standard fluorochemical emulsion treatment (Sample 13—comparative); and (3) untreated (Sample 14—untreated).
[0000]
TABLE 1
ppm OWF (on
ppm OWF
weight of fiber)
elemental
Sample #
Clay Nanoparticle
clay
flourine
1
Laponite ® RD
1750
0
2
Laponite ® RDS
1740
0
3
Laponite ® JS
1950
0
4
Laponite ® RD
1700
150
5
Laponite ® RDS
1800
150
6
Laponite ® JS
1830
140
7
Laponite ® RDS
1500
150
8
Laponite ® RDS
1000
75
9
Laponite ® RDS
2000
75
10
Laponite ® RDS
1500
150
11
Laponite ® RDS
1000
200
12
Laponite ® RDS
2000
200
13 (comparative)
NA
0
640
14 (untreated)
NA
0
0
[0029] Samples 1-7 were all prepared in a similar manner, with the main difference being the weight percent and type of stock Laponite® solution made and the addition of Capstone® RCP to Samples 4-7. For illustrative purposes only, the following describes the method of preparing Sample 7: A 5% by weight stock solution of Laponite® RDS was made by incrementally adding the nanoclay to stirring water that was heated to about 38° C. After addition was completed, the vessel was moved to a cool stir plate and continued to stir until the solution was dispersion clear and at room temperature. In a bottle were combined 6 wt % Capstone® RCP, 60 wt % of the Laponite® dispersion, and the remainder dionized water. The solution was shaken, poured into the reservoir of an 8 ounce spray bottle, and primed into a waste container. The spray bottle was clamped onto a ring stand approximately 12 inches from the base and aimed at a downward angle. The spray pattern was tested and centered on a grid. A tare weight for the carpet was obtained, then the carpet was placed on the grid so that the bottom right corner of the carpet would be contacted by the spray. The carpet was then moved so that the bottom half of the carpet would be sprayed. The carpet was again moved so that the left bottom corner was sprayed, then the left half, then top left corner, top half, top right corner, and right half, followed by a spray aimed at the center to achieve full coverage. After spraying on the carpet surface, the carpet was cured in a convection oven at 150° C. for 5 minutes. The resulting dispersions, when sprayed on the Sample at about 5% WPU, resulted in 1500 ppm OWF of clay nanoparticles and 150 ppm OWE of elemental flourine on the surface of the Sample.
[0030] Samples 8-12 were prepared in a similar manner, except that the resulting dispersions, when sprayed on the Samples at 10% WPU, resulted in from about 1000-2000 ppm OWF of clay nanoparticles and from about 75 ppm-200 ppm OWF elemental fluorine, on the surface of the Samples.
[0031] Sample 13 was prepared with a 13.3 wt % Capstone® RCP solution and following a spray pattern similar to the method described above at a 10% wet-pick up, which resulted in 640 ppm OWF of elemental fluorine on the surface.
[0032] The Samples were then soiled according to ASTM D6540. For Samples 1-7 and 13, each drum load contained at least one piece of untreated control carpet (“Control”).
[0033] Tables 2 and 3, below, lists the Delta E values for Samples 1-14. Table 2 compares the Delta E values for Samples 1-7, and 13 with the Control described in the previous paragraph. Table 3 compares Samples 8-12 with Sample 13, which is the fluorine only treated carpet.
[0000]
TABLE 2
Sample Delta E with
Control Delta E
% soil retained
Sample #
Std. Dev.
with Std. Dev.
vs. Control
1
15.7 ± 0.6
19.6 ± 0.6
80
2
15.1 ± 1.2
18.7 ± 0.6
81
3
15.5 ± 0.3
18.6 ± 0.1
83
4
14.9 ± 1.0
19.6 ± 0.6
76
5
14.1 ± 0.8
18.7 ± 0.6
75
6
14.3 ± 0.7
18.6 ± 0.1
77
7
16.1 ± 1.0
23.4 ± 0.5
69
13 (compara-
16.0 ± 0.8
20.1 ±. 0.5
80
tive)
14 (untreated)
21.9 ± 1.0
NA
NA
[0034] Samples 1-7 show between a 17% to 31% decrease in soil retained verses the Control.
[0000]
TABLE 3
Sample Delta E with
Sample #
Std. Dev.
Delta E difference to Sample 13
8
18.1 ± 0.7
−2.1
9
16.5 ± 1.6
−0.5
10
15.0 ± 0.6
+1.0
11
17.0 ± 1.2
−1.0
12
15.5 ± 0.8
+0.5
13 (comparative)
16.0 ± 0.8
—
14 (untreated)
21.9 ± 1.0
+5.9
[0035] Samples 8-12, when compared to Sample 13, show the benefit of the clay nano-particles, which result in about the same Delta E to 1.0 decrease in Delta E over a carpet with 3× the fluorine and no clay nano-particles (Sample 13). Thus, a more environmentally friendly carpet fiber, with the same or improved drum soiling, can be achieved with the disclosed soil repellency aqueous dispersions.
[0036] The invention has been described above with reference to the various aspects of the disclosed soil repellency aqueous dispersions, treated fibers, yarns, and textiles, and methods of making the same. Obvious modifications and alterations will occur to others upon reading and understanding the proceeding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the claims.
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A soil repellency aqueous dispersion for treating various fibers, yarns, and textiles is disclosed. The dispersion provides superior soil resistance when compared to known fluorochemical and silicone fiber treatments. The dispersion comprises clay nanoparticle components and fluorochemicals that can be applied to the fibers, yarns, and textiles using known methods.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is generally drawn to element fasteners and more particularly to clips or fasteners used in refrigerators or freezers for retaining internal elements.
[0003] 2. Description of the Prior Art
[0004] Refrigerators and freezers have internal walls to which various elements such as doors, handles ice makers, shelves etc. must be secured. This internal wall has preformed apertures in area where the internal elements are to be fastened which open into a blown insulating foam area located between the internal walls and external walls.
[0005] Some presently known clips for retaining the mentioned internal elements are inserted into the preformed apertures prior to the foam insulation being blown into the insulating area. The force of the blown insulation tends to dislodge or move the clip out of position preventing the proper engagement of the internal element. Hence the prior art clips were glued to the internal walls to prevent such dislodgements.
[0006] Other types of fasteners were inserted into the foam insulation after the insulation is already blown in. By way of example three different fasteners are described in the following U.S. Patents.
[0007] U.S. Pat. No. 4,179,977 teaches a rectangular shaped one piece plastic fastener that is insertable in a rectangular shaped hole in a refrigerator or freezer cabinet panel which accommodates a screw for securing a compartment element in the refrigerator. It has a single central box like structure for retaining a screw mounting the refrigerator element.
[0008] U.S. Pat. No. 4,040,463 teaches a circularly shaped one piece plastic fastener that is insertable in a preformed aperture of a refrigerator or freezer cabinet panel and which accommodates a screw for securing a compartment element in the refrigerator. It also has a central box like structure for retaining a screw mounting the refrigerator element.
[0009] U.S. Pat. No. 4,648,766 teaches a circularly shaped one piece plastic fastener that is insertable in a preformed circular aperture of a refrigerator or freezer cabinet panel and which accommodates a screw for securing a compartment element in the refrigerator. It has a central structure for retaining a member for mounting the refrigerator element.
[0010] None of these fasteners provide both a first deformable wing type structure for securing the refrigerator element and a second deformable wing type structure for retaining the clip in the foam. What was needed was such a two wing fastener or clip which would more positively retain the refrigerator element to the inner panel as well as to the foam insulation.
SUMMARY OF THE INVENTION
[0011] The present invention solves the problems associated with the mentioned prior art devices as well as others by providing a deformable plastic refrigerator or freezer fastener having a rectangular shaped head and a double winged leg extending there from fitting through a preformed aperture in the refrigerator panel to lock the refrigerator element by way of the first wing comprising an angled protuberance on two sides of the clip and to hold itself to the foam by way of the second wing. The clips flat top surface has a hole therein for expanding the first wing to retain a refrigerator element such as a door handle, ice maker, etc. to the user panel. The end of the clip has the second wing element which deforms into the foam to positively hold the clip and refrigerator element.
[0012] In view of the foregoing it will be seen that one aspect of the present invention is to provide a refrigerator clip for positively retaining a refrigerator member to both the refrigerator inner panel and the foam insulation behind the panel.
[0013] Another aspect is to provide a refrigerator clip having a sharp end for easily piercing the foam insulation behind the refrigerator inner panel.
[0014] Still yet another aspect is to provide a refrigerator clip having a pair of deformable wings.
[0015] These and other aspects of the present invention will be more fully understood from a review of the following description of the preferred embodiment when considered in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In the drawings wherein:
[0017] [0017]FIG. 1 is a side perspective view of the refrigerator/freezer clip of the present invention;
[0018] [0018]FIG. 2 is a top perspective view of the FIG. 1 clip;
[0019] [0019]FIG. 3 is a cut away side view of the clip of FIG. 1; and
[0020] [0020]FIG. 4 is a cut away schematic sectional side view of the FIG. 1 clip mounted in the refrigerator to retain a refrigerator member.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring now to the drawings wherein the showing are for purposes of illustrating a preferred embodiment of the present invention and are not intended to limit it thereto, FIGS. 1-3 show a deformable refrigerator clip ( 10 ) made from an Acetal deformable plastic material having a rectangular head portion ( 12 ) approximately 0.5 in. by 0.75 in. having a centrally located circular aperture ( 14 ) there through approximately 0.180 in. in diameter. The large area of the head portion allows a large contact with the refrigerator member (not shown) to minimize rotation of the clip ( 10 ) during assembly. The body ( 16 ) of the clip ( 10 ) is approximately 1.43 in. in length L in the undeformed position and is substantially rectangular shaped to prevent turning when inserted into the foam between refrigerator or freezer panels.
[0022] The clip body ( 16 ) has a pointed end section ( 18 ) forming a triangle of 48° as best shown in FIG. 3. This sharp triangular shape allows easy penetration of the body ( 16 ) into the foam insulation preventing “balling” of the foam insulation and reduces clip ( 10 ) engagement force. A top section ( 20 ) of the body ( 16 ) has a first set of triangular shaped deformable walls ( 22 ) having a pair of internal fingers ( 24 ) formed there from and a first block ( 26 ) located between the fingers ( 24 ) to be able to fit there between when the walls ( 22 ) are expanded out during assembly as will be described later. The block ( 26 ) has a slipped circular opening assembly ( 28 ) aligned with the aperture ( 14 ) comprising a first step ( 30 ) the same 0.180 in. diameter as the opening ( 14 ) and a second smaller step ( 32 ) approximately 0.157 in. in diameter. The clip body ( 16 ) also has a middle section ( 34 ) having a second set of triangular shaped deformable walls ( 36 ) and a second block ( 38 ) located there between having a circular opening ( 40 ) there through aligned with the opening ( 32 ) of the first block ( 26 ) but spaced there from. The opening ( 40 ) is slightly smaller in diameter (0.130) then the opening ( 32 ) but is about twice the depth of the opening ( 32 ). The openings ( 14 ) and ( 30 ) are intended to be larger than the diameter of a self-threading screw intended for mounting the clip ( 10 ) and are lead ins for guiding the screw into the self-threading openings ( 32 ) and ( 40 ). The difference in depths and diameters of ( 32 ) and ( 40 ) makes the first block ( 26 ) strip torque less than the second block ( 38 ) providing a higher range of drive torque to strip torque ratio since strip torque is dependant on the amount of thread capture.
[0023] Turning now to FIG. 4, the clip ( 10 ) is shown in its deformed position mounting a refrigerator member ( 42 ) such as an ice maker, shelf or door handle etc. to an inner refrigerator panel ( 44 ) using a self-tapping screw ( 46 ) such as a #8AB×1 in. length. It will be seen that since the body ( 16 ) has a long empty internal section ( 48 ), different lengths of screw ( 46 ) could be used. In application, the clip ( 10 ) is driven through a preformed aperture ( 50 ) in the inner panel ( 44 ) to extend into the foam ( 52 ) blown between the inner panel ( 44 ) and an outer panel ( 54 ) until the head portion ( 12 ) is resting against the panel ( 44 ). The screw ( 46 ) is now extended through a preformed opening ( 56 ) in the refrigerator member ( 42 ) and into the guide holes (14) and (30) until it reaches the smaller diameter hole ( 32 ). It is now threaded therein causing the first triangular walls ( 22 ) to expand outward causing the first block ( 26 ) to move up between the fingers ( 24 ) until the walls ( 22 are deformed against the inner panel ( 44 ) to securely capture the member ( 42 ) between the top ( 12 ) of the clip and the first set of walls ( 22 ) with the member ( 42 ) firmly locked there between as seen in FIG. 4. Further rotation of the self tapping screw ( 46 ) encounters the opening ( 40 ) and block ( 38 ) is moved up toward the opening ( 32 ) deforming the second set of walls ( 36 ) into the foam ( 52 ) to act as a second retainer for the member ( 42 ). When the clip ( 10 ) is fully deformed, the shaft length L goes from the initial length of 1.37 in. to a deformed length of 1.15 in.
[0024] While an application of the clip is shown for refrigerator parts other uses such as for automotive members attachment is also possible. It will be understood that such other applications and modifications have been deleted herein for the sake of conciseness and readability but are fully intended to fall within the scope of the following claims.
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A retainer clip having a rectangular shaped head and body portion with a pair of spaced block members located between two pairs of triangular shaped deformable walls and a pointed end section with the head portion and the pair of block members having aligned apertures for self threading a screw there through to deform said two pairs of triangular shaped wall to thereby capture a member to a wall panel.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application claiming priority to co-pending U.S. patent application Ser. No. 12/686,847, filed 13 Jan. 2010, which is a continuation-in-part of U.S. patent application Ser. No. 12/315,438, filed 3 Dec. 2008, which is a continuation of U.S. patent application Ser. No. 11/983,009, filed 6 Nov. 2007, now U.S. Pat. No. 7,484,418. The contents and substance of these applications are incorporated by reference as if fully set forth below.
TECHNICAL FIELD
This invention relates to multi-hole pressure probes and more particularly to a multi-hole pressure probe containing piezoresistive sensors fabricated utilizing silicon-on-insulator (SOI) techniques.
BACKGROUND
The so-called multi-hole pressure probe has been a standard technique for measuring mean flow angles, stagnation, and static pressures for over four decades. Generally, these probes make use of the known (through experiment or analysis) geometrical variation of all static pressure on fixed shapes (sphere, cylinder, wedge, etc.) which changes in a repeatable way as a function of that shape's orientation to the flow. Since the Mach number is a unique function of the ratio of stagnation to static pressure, it can also be derived from the pressures measured by such a probe. Up to two orthogonal flow angles as well as stagnation and static pressure can be deduced from pressures measured at four or five well chosen locations on the probe (using five rather than four measurement locations generally improves the accuracy but requires a larger probe). Fewer measurements yield fewer flow variables. For example, if the probe size is a concern, then two measurements can be used to find either one flow angle or stagnation and static pressures. The static pressure ports on these steady state probes are usually connected to remote pressure transducers via long lengths of small diameter tubing. This restricts their time response to several seconds or longer.
With the advent of miniature semiconductor pressure transducers in the late 1960's the pressure transducer could be moved much closer to the measurement location by mounting it in the probe body itself, thus enhancing the time response of the measurement. Such miniature semiconductor transducers were provided by Kulite Semiconductor Products, Inc., the assignee herein. Kulite Semiconductor Products, Inc. has many patents relating to miniature pressure transducers. The development of a miniature semiconductor pressure transducer led to the evolution of a class of so called high frequency response probes, with frequency responses in the kilohertz (KHz) range. Because of the relatively high drift rate of early semiconductor transducers, these probes were only used for unsteady measurements. Conventional remote transducers, fit through separate ports for use in high accuracy measurements of the steady state values. The new technology enabled the fabrication of probes that can survive harsh environmental characteristics as determined by the needs of industry and government, aero propulsion test facilities and the like.
High frequency response of these probes are set by three factors: (1) the frequency response of the transducer (generally much higher than other factors and so not limiting); (2) the resonant frequency of any cavity between the surface of the probe and a transducer diaphragm; and (3) the vortex shedding frequency of the probe body (which scales with the probe size and the fluid velocity). The latter two factors, 2 and 3 scale with the probe size so that smaller probes will yield higher usable frequency response.
Recent advances in semiconductor transducer technology have greatly improved the stability and accuracy, as well as increase the temperature range of the transducer. These advances combine to suggest that very small probes with wider dynamic range can measure the entire frequency range from steady state to over 10 KHz. Therefore, to improve the frequency response of such probes a smaller, flatter sensor with no cavities is required. In addition, the static responses of the transducers used in the probe are limited by the static properties of the sensors used in these probes. The sensing diaphragm made by solid state diffusion uses a P-N function to isolate the sensing network from the lower underlying bulk deflecting member. Since it is made using P-N junction isolation, of course static thermal properties are now limited in their upper temperature usefulness. Recent work has resulted in the manufacture of a new type of piezoresistive sensor using SOI techniques wherein the piezoresistive network is isolated from the deflecting material by an oxide layer, while being molecularly attached to it such is shown in FIG. 1 of U.S. Pat. No. 5,286,671 entitled, “Fusion Bonding Techniques for Use in Fabricating Semiconductor Devices,” by Dr. A. D. Kurtz and assigned to Kulite Semiconductor Products, Inc., the assignee herein. The process for fabricating the composite dielectrically isolated structure requires the use of two separate wafers. The first “pattern” wafer is specifically selected to optimize the piezoresistive performance characteristics of the sensor chip, while the second “substrate wafer” is specifically selected for optimizing the micromachined capabilities of the sensing diaphragm. A layer of the higher quality thermally grown oxide is then grown on the surface of the substrate, while the piezoresistive patterns are introduced onto the pattern wafer. The piezoresistive patterns are diffused to the highest possible concentration level, equal to solid solubility, in order to achieve the most stable, long term electrical performance characteristics of the sensing network. Once the pattern and the substrate wafers are appropriately processed, the two wafers are fusion bonded together in accordance with the above-noted U.S. Pat. No. 5,286,671. The resulting molecular bond between the two wafers is as strong as the silicon itself, and since both the sensing elements and the diaphragm are made from the same material, there is no thermal mismatch between the two, thus resulting in a very stable and accurate performance characteristic with temperature. The presence of dielectric isolation enables the sensor to function at very high temperatures without any leakage effects associated with the P-N junction isolation type devices. Since the device is capable of operating at high temperatures, a high temperature metallization scheme is introduced to enable the device to interface with the header at these high temperatures.
The transducer formed by the techniques depicted in U.S. Pat. No. 5,286,671 as indicated above, enables the use of a probe which has an improved high frequency operation while being extremely small. The probe is basically a longitudinal tubular member having a front probe surface which contains holes or apertures. Each hole or aperture is associated with a separate transducer where each transducer contains a separate housing, which housing fits into the hole in the transducer probe. When mounting each transducer in its own miniature header, multiple transducers can be used simultaneously in a probe while further enabling the probe to be very small (less than 100 thousands of an inch, i.e. 100 mils, in diameter).
SUMMARY
A miniature pressure probe is disclosed herein. The pressure probe comprises: a longitudinal tubular body symmetrically disposed about a central axis and having a given diameter, the body having a front conical end and a back end, a plurality of transducer accommodating ports disposed about the front end, a plurality of leadless SOI transducers each having an active deflection area associated with a semiconductor substrate, each transducer having a header for supporting the same, with the transducer header having a thickness substantially less than the probe diameter, with each header and transducer positioned in an associated transducer port of the probe and operative to respond to flow pressure. Additionally, the header can comprise a flange weldable to a counter-bore and its associated transducer port, so as to seal the transducer header to the probe body.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a cross-sectional view of a transducer and header arrangement fabricated by SOI technology.
FIG. 2 is a perspective view of a transducer showing a glass contact wafer positioned above a silicon sensor wafer according to an embodiment of this invention.
FIG. 3 consists of FIGS. 3A-3B , with 3 A being a front view of a probe, while FIG. 3B is a cross-sectional view taken of the same probe taken through line A-A of FIG. 3A .
FIG. 4 consists of FIGS. 4A-4B , with FIG. 4A being a top view of a transducer having a housing according to this invention. FIG. 4B is a cross-sectional view of the housing and sensor arrangement of FIG. 4A .
FIG. 5 consists of FIGS. 5A-5B , with FIG. 5A being a front view of a probe having a sensor assembly according to this invention. FIG. 5B shows a cross-sectional view of the sensor of FIG. 5A having an angled probe body.
FIG. 6 consists of FIGS. 6A-6B depicting an angle and static probe front view in FIG. 6A and depicting a cross-sectional view of the angle and static probe taken through line A-A of FIG. 6A .
FIG. 7 consists of FIGS. 7A-7B illustrating a transducer structure in which a header of the transducer comprises a weldable flange. FIG. 7A illustrates a front view of the transducer structure, while FIG. 7B illustrates a cross-sectional side view.
FIG. 8 consists of FIGS. 8A-8B illustrating a receiving portion of the probe body having a counter-bore for receiving the flange of the transducer structure. FIG. 8A illustrates a front view of the transducer structure, while FIG. 8B illustrates a cross-sectional side view.
FIG. 9 consists of FIGS. 9A-9B illustrating an all-welded 5-sensor probe, with FIG. 9A being a front view and FIG. 9B being a cross-sectional side view of the probe.
FIG. 10 consists of FIGS. 10A-10B illustrating an all-welded 4-sensor probe, with FIG. 10A being a front view and FIG. 10B being a cross-sectional side view of the probe.
DETAILED DESCRIPTION
According to an embodiment of the invention, a multi-hole pressure probe has an internal hollow and has on the front end of the probe a plurality of apertures which communicate with the internal hollow. A pressure transducer has a first layer of semiconductor material bonded to a glass contact substrate, the semiconductor material having a central active area which deflects upon application of a force and a surface of the material is coated with an oxide layer. Positioned on the oxide layer are piezoresistive sensing elements. These sensing elements are positioned within a cavity on the glass substrate when the contact glass wafer is bonded to the semiconductor material. The glass substrate has apertures which are filled with a glass metal frit and contain header pins. The entire transducer is positioned within a separate header. A plurality of such transducers, are each positioned in its own header, and each is individually inserted into a respective aperture of the probe. This enables the measurement of flow angles, static pressures, within the structure. By mounting each sensor in its own miniature header, four or five such sensors can be used simultaneously in a probe while enabling the probe to be very small.
Referring to FIG. 1 there is shown a transducer configuration using SOI techniques. In this technique, the piezoresistive network indicated by reference numerals 24 and 25 is configured in a Wheatstone bridge configuration and the piezoresistors as 24 and 25 which are four in number are isolated from the deflecting material by an oxide layer 12 .
FIG. 1 also shows a surrounding header 44 which header houses and encloses the transducer apparatus. The process for fabricating the composite dielectrically isolated structure as shown in FIG. 1 requires the use of two separate wafers. The term substrate is used synonymously with the term wafer and is defined as being a small disc of material, either semiconductor or glass. The first pattern wafer is selected to optimize the piezoresistive performance characteristics of the sensor chip, while the second substrate wafer is specifically selected to optimize the micromachining capabilities of the sensing diaphragm. Once the wafers are bonded together, the non-doped side of the pattern wafer is selectively removed and the P+ network is left bonded to the oxide layer positioned on the substrate wafer. This forms a composite dielectrically isolated wafer. The deflection area is designated by reference numerals 40 and 41 , with center boss designated as 42 . Essentially, the regions 40 and 41 are thin regions, also called active areas, which deflect upon application of a force thereto. The piezoresistive sensors 24 and 25 are located within the active areas 40 and 41 and as indicated will vary their resistance upon application of a force thereto. The sensors 24 and 25 are also associated with contact areas which basically are metal and enable the device with the header to operate at desired temperatures. The metallization that is used for establishing high temperature contacts is PtSi/Ti/Pt. In this manner, the first layer of Pt silicide is used to create a high temperature ohmic contact to the device, the second (Ti) is used as both an adhesion layer and a barrier that prevents the top Pt layer from diffusing into the underlying PtSi ohmic contact layer at very high temperatures. Platinum (Pt) is used as a top layer because it is highly inert and is very suitable for high temperature operation.
Once the metallized contact barriers are defined, (e.g., using conventional photolithographic technology), the micromachining of the deflecting diaphragm takes place. The micromachining as for example, the machining of areas 40 , 41 and 42 is performed using either a combination of different wet (isotropic and anisotropic) chemical processes or deep reactive ion etching (DRIE) can also be implemented. The shape and performance characteristics of the micromachined sensing or deflecting diaphragms are modeled using finite element analysis, and the SOI sensing chip is configured to be directly mounted into the probe body, thus eliminating redundancy and sensor packaging in probe installation which have historically increased the probe size. This also facilitates a better thermal match within the chip and its mount improving stability and accuracy. As indicated the piezoresistive patterns are isolated from the silicon substrate 11 by the silicon dioxide layer 12 .
The layer of silicon dioxide is preferably a high quality grown oxide which is then grown on the surface of the substrate, while the piezoresistive patterns are introduced into the pattern wafer. The piezoresistive patterns are preferably diffused in highest possible concentration level equal to solid solubility, in order to achieve the most stable long term electrical performance characteristics of the sensing network. Once the pattern and the substrate wafers are appropriately processed, the two are fusion bonded together using the techniques described in the above noted U.S. Pat. No. 5,286,671 which is incorporated herein in its entirety. The resulting molecular bond between the two wafers is as strong as silicon itself and since both the sensing elements and the diaphragm are made from the same material, there is no thermal mismatch between the two, thus resulting in a very stable and accurate performance characteristic with temperature. The presence of dielectric isolation in the composite wafer 11 enables the sensor to function at very high temperatures without any leakage effects associated with the P-N junction isolation type devices.
As seen, bonded to the composite sensor 11 is a glass wafer contact wafer 16 . The glass contact wafer 16 contains apertures 20 . The apertures 20 eventually receive a glass metal frit to make contact with the contacts 34 associated with the piezoresistive sensors 24 and 25 . The header contains a header glass layer 30 which layer is attached to the contact glass wafer by means of a glass frit bonding agent. As indicated the apertures 20 are filled with a glass metal frit and header pins 31 and 32 are inserted into each of the apertures before the glass metal frit hardens. When the glass metal frit hardens the header pins 31 and 32 are permanently retained within the glass metal frit filled apertures as 20 .
Referring to FIG. 2 there is shown an exploded view of the semiconductor transducer depicted in FIG. 1 . The transducer is shown without a header but basically shows the glass contact wafer 73 which is wafer 16 of FIG. 1 together with the contact through holes 70 and 71 . Cavity 72 is formed in the contact glass wafer which cavity 72 enables diaphragm deflection. Bonded to the contact glass wafer 73 is a silicon composite sensor wafer 76 which is wafer 11 of FIG. 1 . The wafer 76 has grown thereon a layer 77 of, for example, silicon dioxide 77 . The layer 77 is configured as a peripheral rim which surrounds the active regions of the wafer 76 . The wafer 76 contains piezoresistors as 81 , 82 , 83 , and 84 . These are analogous to piezoresistors 24 and 25 of FIG. 1 . Thus as seen, there are four piezoresistors which are connected to form a Wheatstone bridge. The piezoresistors are P-type silicon piezoresistors protected by a silicon dioxide or other oxide coating.
Part of the connections, as indicated in FIG. 2 are made on the composite sensor wafer by means of connective land areas 80 which are connected at one end to a piezoresistor and at another end to another piezoresistor thus forming one arm of the bridge. The conductive land areas are each associated with a contact, such as contact 70 for land area 80 . The configuration is well known and offers many advantages as indicated above. The leadless technology in accordance with U.S. Pat. No. 5,955,771, entitled “Sensor for Use in High Vibrational Applications and Methods for Fabricating the Same”, to A. D. Kurtz, and A. Ned and assigned to the assignee herein and U.S. Pat. No. 5,973,590, entitled “Ultra-Thin Surface Mount Wafer Sensor Structures and Methods for Fabricating the Same” by A. D. Kurtz, A. Ned and S. Goodman, issued in 1999 to Kulite Semiconductor Products, Inc., show this technology (described above), thus achieving substantial sensor size reduction.
This technology as employed in FIGS. 1 and 2 is entirely capable of high frequency and high accuracy performance in high temperature, harsh environments. The leadless technology enables the mounting of the sensor chip “upside down” thus exposing only the backside of the sensor chip to the applied pressure. This is shown in FIG. 1 where the force (F) is applied to the top side of the silicon composite wafer. Meanwhile, the piezoresistors are isolated by the cavity 72 between semiconductor composite sensor wafer 11 and the glass contact wafer 16 . The leadless technology also eliminates the use of gold wire bonds which can fail at high temperatures, under high vibration, or under dynamic pressure conditions. Thus, one uses a very high temperature glass/metal frit to connect between the leadless chip and a leadless header 44 on which the chip is mounted. The fabrication of the leadless chip requires processing of silicon on insulator (SOI) pattern wafer and the ceramic glass wafer.
The ceramic glass wafer which is designated as the contact glass wafer as 16 of FIG. 1 and 73 of FIG. 2 is micromachined to be molecularly bonded to the pattern side of the SOI composite sensor wafer 76 of FIG. 2 or wafer 11 of FIG. 1 using the Anodic Bond method. The molecular bond takes place between the ceramic glass and the dielectrically isolated P+ Si layer. The bond takes place around the active area, the contact regions and also over the entire extending rim 85 of FIG. 2 . Once the bond is made the sensing area is hermetically sealed from the surrounding environment, while the contacts are left accessible for interconnections only through adjacent openings in the contact glass. The contact areas are then filled with a thermally matched glass/metal frit and the chip is mounted onto a header using a high temperature non conductive glass. This glass is designed to fire at the same temperature as the glass/metal frit. Such glasses in combination with metals are well known and many examples exist in the prior art. The connections between the filled contacts and the header pins are made at the same time. Once the chip is mounted onto the header, only the backside of the sensor chip is exposed to the pressure medium as shown in FIG. 1 . It is of course understood that the piezoresistors of 24 and 25 are hermetically protected and the overall thickness of the header-chip combination can be made as small as 10-20 mils (1 mil is equal to one-thousandth of an inch, i.e. 0.001 inch). The typical chip as shown in FIG. 1 and FIG. 2 will have an overall dimension on the order of 20 to 30 mils in diameter with a membrane thickness of 0.01 to 0.02 mils and having a high sensitivity and high accuracy. By designing the chip to have optimized sensing membranes by using Finite Element analysis software to model the chip's mechanical performance sensors having: 1) overall dimension on the order of 20 to 30 mils in diameter, 2) membrane thickness of 0.01 to 0.02 mils, 3) high sensitivity and 4) high accuracy are obtained. The probe design will take the full benefit of all the descried sensor features and will implement the custom designed leadless packaging methods. Such a structure, when used as the sensor in a multiple-hole pressure probe gives rise to a number of advantages. By mounting each leadless sensor in its own miniature header four or five such sensors can be used simultaneously in a probe, while enabling the probe to be very small (less than 100 mils in diameter) as shown in FIG. 4 . Since the leadless sensor is first affixed to its own header, the header sensor structure can have its leads attached before mounting in the probe as shown in FIG. 5 . The small diameter and thickness of the mounted sensor/header combination makes it possible to pass the leads out of a central aperture in the probe body (shown in FIG. 6 ) and then affix the sensor header structure to a prepared position on the probe. The small overall thickness of the header-chip combination also insures that when mounted on the probe, it will not protrude past the surface and thus avoid distortion of the airflow. The design of the probe body can be customized for any application with the sensor/header selection kept separate. The probes utilizing this type of construction will be truly robust and capable of withstanding harsh environments, while exhibiting excellent performance characteristics. The probe design makes use of the full benefit of all the described sensor features and can be utilized to design specifically high frequency and reliable probes.
Referring to FIG. 3 , which consists of FIGS. 3A and 3B , there is shown an angled probe according to this invention and employing the transducers as depicted FIG. 1 and FIG. 2 . FIG. 3A shows a front view of the probe. As seen, the probe 100 is circular in cross-section and has four probe holes or apertures, namely 120 , 130 , 121 and 135 . The probe 100 has a front conical surface as can be seen in FIG. 3B which shows a cross-sectional view taken through line 3 B- 3 B of FIG. 3A . As seen, the probe 100 has an internal cavity 110 and is basically symmetrically disposed about the center line or axis 114 . Each aperture contains a separate transducer, such as 101 and 103 , and each transducer is associated with a separate sensor structures, such as 102 or 104 . The transducers 101 and 103 are the transducer structures shown in FIGS. 1 and 2 . Thus the transducers have extending pins as pins 105 a , 105 b for transducer 101 and pins 106 a , 106 b for transducer 103 . As seen, each transducer has its own housing which housing is accommodated by a probe aperture or port. The front of the probe, as indicated, is generally conical in shape. Each pin associated with the transducers is connected to its own wire as indicated by wires 111 a and 111 b for transducer 101 , and 112 a and 112 b for transducer 102 . When used as a sensor in a multiple-hole pressure probe, such a structure as shown in FIG. 3 gives rise to a number of great advantages. By mounting each leadless sensor in its own miniature header, four or five such sensors can be used simultaneously in a probe, while enabling the probe to be extremely small (less than 100 mils in diameter). Since the leadless sensor structure is first affixed to its own header, the header sensor structure can have its leads attached before mounting in the probe. This is clearly shown in FIG. 4 .
Thus, in FIG. 4 , which consists of FIGS. 4A and 4B , there is shown a transducer header 141 , or housing, which accommodates the sensor configuration 140 as that of FIGS. 1 and 2 . The transducer header 141 as indicated contains the sensor 140 and is associated with pins 142 and 143 , where each pin has a wire such as 144 and 145 emanating there. These are analogous to pins 105 a and 105 b of FIG. 3 .
FIG. 5A shows the front view of a probe 152 . The probe has four apertures designated as 151 , 153 , 154 , and 155 . FIG. 5B shows a cross-sectional view. It is seen that the probe 152 is again symmetrically disposed about axis 156 and has the apertures 154 , 153 adapted to accommodate an associated transducer as shown in FIG. 4 . Thus, as seen the aperture 154 has a top portion which is of a size adapted to enclose and contain the transducer header 141 . The bottom portion of the aperture 154 has an opening 155 which communicates with the internal hollow 157 of the probe 152 . Also aperture 153 has a top portion to accommodate the transducer and a smaller bottom portion 158 which also communicates with the hollow 157 of the probe. As one can see, the configuration depicted in FIG. 4B together with wires 141 and 145 can be inserted into aperture 154 with the wires as 144 and 145 directed through the bottom portion or aperture 155 into the internal hollow 157 of the probe. In this manner, the entire structure is extremely compact and utilizes for example in particular in regard to FIG. 5 as well as FIG. 3 , four separate transducers to measure four different flow values.
Referring to FIG. 6 , there is shown FIG. 6A which depicts a front view of an angle and static probe 160 . FIG. 6B is a cross-sectional view taken through line 6 B- 6 B of FIG. 6A . As seen, from FIG. 6A the probe 160 has a circular configuration and has port apertures 161 , 162 , 163 , 166 and 167 . Apertures 163 , 166 and 167 are located on the flat front surface 164 of the probe with aperture 163 located at the center of the probe on the flat surface 164 while apertures 161 and 162 are positioned on the angled front portion of the probe as depicted in FIG. 6B .
As seen in FIG. 6B , each aperture, such as 161 , 162 , and 163 contains its own transducer structure. For example, transducer structure 169 is contained in aperture 161 ; transducer structure 173 is contained in aperture 162 , and transducer structure 171 is contained in aperture 163 . Aperture 163 communicates with an extended passage 168 where the end of passage 168 communicates with an aperture containing transducer structure 171 . Each of the transducers is also associated with respective pins, as pins 180 a , 180 b associated with transducer 169 ; pins 182 a , 182 b associated with transducer 173 ; and pins 184 a , 184 b associated with transducer 171 . The probe housing has openings surrounding each of the pins to enable the pins to be connected to wires such as 181 a , 181 b connected to pins 180 a , 180 b respectively, wires 185 a , 185 b connected to pins 184 a , 184 b respectively and wires 183 a , 183 b connected to pins 182 a , 182 b respectively. This enables connections to the piezoresistive sensor arrangements on each of the transducers. Thus, as one can ascertain, by mounting each leadless sensor in its own miniature header to provide probe design that enables a multiple number of transducers to be employed in a single probe. Since the leadless sensor is affixed to its own header the resultant transducer structure can have its leads attached before mounting in the probe as explained above. The small diameter and thickness of the mounted sensor/header combination makes it possible to pass the leads out of a central aperture in the probe body as shown for example in FIG. 6 and then affix the sensor header structure to a prepared position on the probe. The design of the probe body can be customized for any application where the sensor/header selection kept separate.
The probes utilized in this type of construction are truly robust and capable of withstanding harsh environments while exhibiting excellent performance characteristics. Additionally, the new leadless assembly/packaging of the probes enables one to implement an additional center transducer as shown in FIG. 6 . This does not increase the size of the overall miniature probe. The central transducer is used for static measurements by placing it in the probe body itself and allowing a narrow tube to extend out to the front of the transducer to measure pressure applied to the front. This is a very useful configuration and is simply implemented with the transducers and headers depicted above.
FIGS. 7A-10B illustrate yet another novel construction of a pressure probe. The above-described pressure probes can utilize various methods for securing the leadless headers of the transducer structures into the probe apertures. For example, a header can be secured into an aperture through glassing or epoxing. These methods, however, can limit the overall performance of the probe. FIGS. 7A-10B illustrate various portions and components of an all-welded construction of the ultra miniature probe.
Specifically, FIGS. 7A-7B illustrate a transducer structure 740 in which a header of the transducer comprises a weldable flange 715 . FIG. 7A illustrates a front view of the transducer structure 740 , while FIG. 7B illustrates a cross-sectional side view. As shown in FIG. 7 , in the welded construction approach, the headers 710 can be welded to the probe body 820 (see FIGS. 8A-10B ) within transducer ports 830 (see FIGS. 8A-10B ), or receivers, of the probe body 820 . A header 710 of a transducer structure 740 can be a specially designed leadless header 710 containing an additional ultra thin flange 715 at its front, as shown in FIGS. 7A-7B .
FIGS. 8A-8B illustrate a transducer port of the probe body having a counter-bore for receiving the flange 715 of the transducer structure 740 . FIG. 8A illustrates a front view of the transducer structure, while FIG. 8B illustrates a cross-sectional side view. As shown, the probe body 820 is designed to contain transducer ports 850 having specific recesses (counter-bores) 855 to accept the thin flanges 715 from the individual headers 710 . In other words, the probe body 820 can comprise a plurality of transducer ports 850 for receiving the transducer structures 740 . Each transducer port 850 defines an aperture 858 for receiving the transducer structure 740 , and further comprises a counter-bore 855 for receiving the flange portion 715 of the header 710 of the transducer structure 740 .
FIGS. 9A-9B and 10 A- 10 B illustrate fully assembled all-welded pressure probes, with FIGS. 9A and 10A being front views and FIGS. 9B and 10B being cress-sectional side views. In the all-welded probe, the leadless sensors are mounted onto the header 710 , such as by utilizing the mounting process described in U.S. Pat. No. 5,955,771, entitled “Sensors for Use in High Vibrational Applications and Methods for Fabricating Same,” which is owned by Kulite Semiconductor Products, Inc. After the sensors are mounted, the headers 710 can be inserted into the probe body 820 and secured into place, to result in those probes depicted in FIGS. 9A-9B and 10 A- 10 B. In an exemplary embodiment, securing a header 710 in place can be accomplished by welding the header 710 to its associated transducer port 850 in the probe body. Welding can be performed about the flange 715 , to weld the flange 715 to the counter-bore 755 of the associated transducer port 850 , in a weldable area 910 , as shown in FIGS. 9A and 10A . During welding, an overlapping spot weld process or other conventional welding methods can be used.
This novel approach eliminates all of the prior mounting difficulties by completely eliminating the use of glues and epoxies. The elimination of glues and epoxies, in combination with using only ultra high temperature materials, enables the construction of an ultra high temperature probe suitable for operation above 500° C. This method and construction also avoids the performance problems that epoxy use can cause, for instance hysteresis, non-linearity, and unusual temperature effects. This approach additionally eliminates leakage paths between the front of the probe (front of the sensors) and rear of the probe (back of the sensors). In contrast to prior designs relying on glassing or epoxing, the all-welded design can assure hermetic isolation.
A 5-hole probe 900 design of the all-welded construction is shown in FIGS. 9A-9B , while a 4-hole design 1000 is shown in FIGS. 10A-10B . While only 4 and 5-hole designs are depicted, an all-welded pressure probe can accommodate the use of four sensors (4-hole probe), five sensors (5-hole probe), or various other numbers of sensors.
It should be obvious to one skilled in the art that there are many additional configurations that can be employed and to fabricate probes of different sizes and construction. All of these alternate embodiments are deemed to be encompassed within the spirit and scope of the claims appended hereto.
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Embodiments of an ultra miniature pressure probe are disclosed. The pressure probe can include a probe body, a plurality of transducer ports, and a plurality of transducers. The probe body can be a longitudinal tubular body having a front conical end. The transducer ports can be disposed about the front end of the body. The transducers can be leadless SOI transducers, each having an active deflection area associated with a semiconductor substrate. Each transducer can be in communication with a header for supporting the transducer. The header can have a thickness substantially less than the probe diameter and can comprise a flange about an edge of the header. Each of the plurality of transducer ports can define an aperture and a counter-bore, wherein each transducer is positionable in an associated transducer port with the flange of the header of the transducer being welded to the counter-bore of the transducer port.
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This is a continuation of application Ser. No. 08/938,481, filed Sep. 30, 1997, now U.S. Pat. No. 5,895,753 which was a continuation of application Ser. No. 08/336,039, filed Nov. 8, 1994, now abandoned.
FIELD OF THE INVENTION
The present invention relates to a method for the in vitro production of protein in which input DNA is transcribed and translated in a two-step reaction performed in a single vessel at a constant temperature.
BACKGROUND OF THE INVENTION
The techniques of modern molecular biology have made possible the manipulation of DNA as well as the other cellular components expressed from the genes contained in the DNA of an organism. In living cells, DNA is transcribed to make mRNA which is then used as a template, in a process called translation, to make a protein whose sequence is determined by the DNA. In developing the modern tools of molecular biology, research has been directed toward ways to perform various steps of the transcription or translation processes in vitro under controlled conditions and with defined inputs. These procedures mimic, in essence, similar processes that occur in a much more heterogeneous mixture in living cells.
Even before the advent of modern recombinant technology, cell extracts were developed which allowed the synthesis of protein in vitro from purified mRNA transcripts. Since that time, several systems have become widely available and are used for the study of protein synthesis and RNA structure and function. To synthesize a protein under investigation, a translation extract must be "programmed" with an mRNA corresponding to the gene or protein under investigation. The mRNA is most often added exogenously in purified form. Historically, such mRNA templates were purified from natural sources or, using more recently developed technologies, prepared synthetically from cloned DNA using bacteriophage RNA polymerases in an in vitro reaction. The preparation of such mRNAs, even by in vitro synthesis, remains a rather tedious process, and this difficulty has limited the practical utility of in vitro translation for a number of applications.
There has consequently been a significant effort in a number of laboratories to develop either coupled or complementary transcription and translation systems which carry out the synthesis of both RNA and protein in the same reaction, beginning with input DNA. These extracts must contain all the components necessary both for transcription (to produce mRNA) and for translation in a single system. In such a system, the input is DNA, which is normally much easier to obtain than RNA and much more readily manipulable. The first such coupled system was based on a bacterial extract. Lederman and Zubay, Biochim. Biophys. Acta, 149:253 (1967). Since prokaryotes normally carry out a coupled reaction within their cytoplasm in any event, this system closely reflected the in vivo process and remains widely used for the study of prokaryotic genes. However, this system is generally not useful for eukaryotic genes, due to its inefficiency and relatively high nuclease content.
Eukaryotic extracts have also been defined that use exogenously added E. coli RNA polymerase or wheat germ RNA polymerase to transcribe exogenous DNA. These systems have had limited success for the general study of eukaryotic genes, due to their low efficiency, and to the fact that they were developed and used prior to the widespread success of cDNA cloning techniques. Other coupled systems have been developed for the study of viral protein synthesis, but are not generally useful for non-viral templates.
In the mid-1980s, the development of highly efficient in vitro transcription systems, particularly ones using phage polymerases such as T7, SP6, and T3, allowed systems to be defined to more efficiently translate cloned mRNA sequences in vitro using translation extracts from wheat germ and rabbit reticulocytes. Perara and Lingappa showed that SP6 RNA polymerase transcription reactions could be added directly to reticulocyte lysate for the production of protein, an insight which illuminated the need to purify the mRNA prior to translation. J. Cell Biol. 101:2292-2301 (1985). Later other workers showed that the transcription and translation could be coupled in reticulocyte lysate by including a phage polymerase and appropriate transcriptional co-factors in the reaction. Spirin et al., Science 242:1162-1164 (1988); Craig et al., Nucleic Acids Res. 20:4987-4995 (1992). More recently, U.S. Pat. No. 5,324,637 describes a coupled transcription and translational system, using reticulocyte lysate and including a phage polymerase, in which the coupling of the two reactions is facilitated by specific conditions, notably the concentration of magnesium ions, which permit both transcription and translation to occur in the same reaction.
Although the coupled approach for transcription and translation systems is useful for many proteins, translation efficiencies can vary widely depending on the type of DNA template which is used (e.g., supercoiled plasmid DNA or linear DNA). In addition, the amount of mRNA synthesized in a coupled reaction is difficult to control under most coupled conditions, such as those described in the aforesaid U.S. Pat. No. 5,324,637. Since the efficiency and fidelity of translation are dependent upon the amount of mRNA added to the reaction, a possible explanation for the undesirable variability of results in a coupled system, in which the reactions occur simultaneously, is that transcription is not consistent between various templates under coupled conditions. Moreover, coupled systems exhibit a marked dependence on the magnesium concentration for the translation efficiency of various templates.
SUMMARY OF THE INVENTION
The present invention is summarized in that a two-step method for transcription and then translation occurs in a single vessel and at a single temperature. One reaction mixture is added to the vessel to create mRNA from a DNA template, with the reaction conditions controlled to limit the concentration of mRNA in the reaction mix. Then, a second set of constituents is added to the same reaction, the second set of constituents effectuating the translation reaction. The result is a dual-stage transcription/translation protocol in which protein is produced in an efficient manner, and at a constant temperature, in a single vessel.
It is an object of the present invention to describe a two-stage transcription/translation methodology which results in a consistent production of protein regardless of the topography of the input DNA.
It is another object of the present invention to provide a two-stage transcription and translation system which is convenient and efficient to operate and can occur at modest temperatures and in short time frames.
Other objects, advantages, and features of the present invention will become apparent from the following specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graphical representation of transcription over time.
FIG. 2 is a graphical representation of the translation that occurs from transcription reactions carried out over time.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed toward a method of performing transcription and then translation using a two-step approach of complementary reactions. The reaction mixture for the transcription reaction is carefully constructed so as, contrary to all prior teachings in the art, to limit the synthesis of mRNA and consequently limit the amount of mRNA to be provided to the translation reaction. Previously, conditions for transcription were usually optimized for maximum production of mRNA. However, it has been discovered that the faithful and efficient production of protein in the translation reaction is facilitated if the initial amount of input mRNA is limited, as described below.
The preferred method in accordance with the present invention contemplates that two separate reactions, i.e. transcription and then translation, will be carried out in a common vessel at a common temperature. A transcription reaction mixture is added to the vessel and provided with template DNA which is to be transcribed. The transcription reaction is then incubated so that transcription is allowed to occur. Then, a translation reaction mixture is added to the same vessel, which has the effect of diluting the transcription reaction mixture by the volume of the translation reaction mixture that is added. The temperature is unchanged and the reaction continues in the same vessel. By limiting the amount of mRNA synthesized to a level between 0.5 and 2.5 micrograms in a 10 microliter reaction (i.e. about 0.05-0.25 μg mRNA per μl of reaction volume), high translation efficiency is maintained without a loss of fidelity in the size or sequence of the protein ultimately produced. Below 0.5 μg, the reaction is inefficient in use of reagents while above 2.5 μg, the amount of mRNA produced can over saturate the translational system for some RNAs. The preferred value is 1 microgram of mRNA in a 10 microliter volume, or 0.1 μg/μl. A level of 0.1 μg/μl in the transcription mixture corresponds to 0.02 μg/μl or 20 μg/ml in the subsequent translation mixture.
There are several ways in which the amount of mRNA synthesized during the transcription reaction can be limited. This can be accomplished in any of a variety of ways that maintain the quality and integrity of the mRNA synthesized, as intact chains, and maintain the compatibility of the reaction with the direct addition of a translation reaction mixture that would allow efficient protein synthesis. In the method described below, the limiting factors include the limited amount of nucleotide triphosphates (NTP's) and magnesium ions available to the reaction, and the performance of the reaction at a modest temperature for a relatively brief time period. In practice, these conditions can be modified, i.e., by increasing one component and decreasing another, while still holding the amount of mRNA synthesized to the required level of 0.5 to 2.5 μg per 10 μl reaction.
In its preferred embodiment, a preferred and convenient transcription reaction mixture and a translation reaction mixture have been developed. These constituents have been developed for a reaction in which the transcription reaction will occur in 10 microliters incubated at 30° C. for 15 minutes. Following that, one would add 40 microliters of the translation reaction mixture and continue to incubate at 30° C. for 60 to 90 minutes for translation to occur. Each of the transcription and translation reaction mixtures can be separately pre-mixed, so that the only reagents which need to be added to the two reaction mixtures are the input DNA template, water, and a choice of either unlabeled methionine or 35 S-methionine, if a radioactive tracer is desired. Other amino acids containing radioactive isotopes or other detectable chemical groups (e.g., biotin) may be substituted by modifying the amino acid supplements accordingly, as is common in the art.
Transcription Reaction Mixture
1. 76.8 mM Hepes-KOH buffer, pH 7.6
2. 4.8 mM magnesium acetate
3. 9.6 mM sodium chloride
4. 1.92 mM spermidine
5. 96 μg/ml acetylated bovine serum albumin
6. 4.8 mM dithiothreitol
7. 0.192 mM each of ATP, CTP, GIP, and UTP
8. 0.8 units/μl placental ribonuclease inhibitor
9. 6.4 units/μl T7 RNA polymerase
10a. 0.5 μg plasmid DNA template with T7 promoter
10b. 2 μl PCR DNA with T7 promoter
Translation Reaction Mixture
1. 50% rabbit reticulocyte lysate, nuclease treated
2. 75 mM potassium acetate
3. 0.45 mM each of ATP, CTP, GTP, and UTP
4. 2.5 mM dithiothreitol
5. 25 mM Hepes-KOH buffer, pH 7.6
6. 10 mM creatine phosphate
7. 31.25 μM 19 amino acids minus methionine
8a. 31.25 μM methionine for a nonradioactive reaction
8b. 1 μCi/μl 35 S-methionine for a radioactive reaction
It can be readily understood that by combining the above two components, a total reaction mixture during the translation part of the process will have a volume of 50 microliters. Calculating out the total concentration of the various constituents of the two mixtures in the total reaction mixture gives the following values.
Final Reaction Mixture
1. 40% rabbit reticulocyte lysate, nuclease treated
2. 60 mM potassium acetate
3. 0.3984 mM each of ATP, CTP, GTP, and UTP
4. 2.96 mM dithiothreitol
5. 35.4 mM Hepes-KOH buffer, pH 7.6
6. 8 mM creatine phosphate
7. 25 μM 19 amino acids minus methionine
8a. 25 μM methionine for a nonradioactive reaction
8b. 0.8 μCi/μl 35 S-methionine for a radioactive reaction
9. 0.96 mM magnesium acetate
10. 1.92 mM sodium chloride
11. 0.384 mM spermidine
12. 19.2 μg/ml acetylated bovine serum albumin
13. 0.16 units/μl ribonuclease inhibitor
14. 1.28 units/μl T7 RNA polymerase
15a. 0.5 μg plasmid DNA template with T7 promoter
15b. 2 μl PCR DNA with T7 promoter
In each of the tables above, where the reaction mixtures includes alternatives, they have been given the same numeral but with an alternate designation, e.g. 10a. and 10b. or 8a. and 8b.
Of the constituents of the two above reaction mixtures, in the transcription reaction mixture, the salts are simply to maintain appropriate ionic conditions to promote transcription and translation. The spermidine is, as is well known to the art, a poly cation which binds to DNA and maintains it in an accessible condition. The serum albumin is a neutral protein carrier to prevent surface interactions of the RNA polymerase and ribonuclease inhibitor. Dithiothreitol is a protein protectant to help maintain the efficacy of enzymes in in vitro solutions. The ribonuclease inhibitor is intended to prevent degradation of the mRNA products which are, after all, the objective of the reaction. The T7 RNA polymerase catalyzes the transcription of mRNA from a DNA template. Clearly, for each of these components, other suitable substitutions can be found to have similar effects. For example, a wide variety of promoters are available and are known to be efficacious for in vitro RNA synthesis, and several of such promoters are phage promoters which have particular specificity and utility for in vitro usage. Those of ordinary skill in the art will readily understand that substitutions to these particular constituents can be made without effecting the overall efficacy of the mixture or the method of its use.
Similarly, in the translation reaction mixture, the rabbit reticulocyte lysate provides, of course, the protein translation assembly necessary to make the proteins. Other cell lysate systems, such as wheat germ lysate can be used as well, as can an assembly of intact ribosomes and translation factors. What is required is simply in vitro competent translation components. The salts and NTPs present in the translation mixture are for proper functioning of translation components. The amino acids are the constituents from which the protein is made and, obviously, one or more amino acids can be tagged radioactively, or tagged by other methods, so as to be detectable in the final expressed protein product. Again, many substitutions for these individual constituents are possible given the ordinary level of skill in the art.
Performing the transcription step in a separate reaction has two major advantages. First it permits control over the amount of mRNA synthesized by adjusting the various reaction components for the transcription reaction without great concern about the effect on the translation reaction. Secondly, it allows for optimal translation in the presence of a single magnesium concentration. A single magnesium concentration (approximately 1 mM) is useful for translation of many types of RNA in a reticulocyte lysate, including both uncapped mRNA as well as uncapped in vitro transcription products from non-EMC and EMC-containing vectors. EMC refers to the 5' non-coding region of the encephalomyocarditis virus, which functions as an internal entry point for initiation of translation by eukaryotic ribosomes, and thus dramatically increases the in vitro translation efficiency of synthetic RNA by reticulocyte lysates. In addition, magnesium concentrations in the range of about 1 mM appear to allow more accurate initiation of translation for standard (non-EMC) RNA transcripts. The reaction mixtures above were optimized to permit efficient protein synthesis simply by adding a translation mix directly to the reaction, and assuming that both reactions would be incubated at the same temperature, i.e. 30° C.
The theory behind the approach of the present invention is that translation efficiency and fidelity vary with the concentration of mRNA in a reaction. Protein synthesis increases in a linear fashion with increasing concentration of mRNA until a maximum or saturation is reached. Higher concentrations of mRNA lead to a decrease in full-length protein products and total amount of protein produced. Different mRNAs saturate the translation process at different concentrations. Globin mRNA, which is the natural template for reticulocyte lysate, saturates at a concentration of 20 μg/ml. Most mRNAs appear to saturate at concentrations between 5 and 80 μg/ml. In spite of this, mRNA concentrations of 5 to 20 μg/ml are often recommended for translation reactions. Our results are consistent with these levels, since we find that transcription conditions limited to produce about 1 μg of RNA in a 10 μl transcription reaction are optimal for translation in 50 μl, which corresponds to an RNA concentration of 20 μg/ml in the translation mixture. Thus by limiting conditions to produce between 0.05 and 0.25 μg/μl in the transcription reaction, the physiologically optimal range of 10-50 μg/ml is achieved. Our results suggest that at high concentrations (>100 μg/ml), the mRNA titrates one or more of the factors responsible for accurate translation initiation and termination, and that an over abundance of mRNA causes the appearance of shortened products that represent aberrant initiation at internal sites in the mRNA as well as premature termination of elongated polypeptide chains.
It is to be well understood by those of ordinary skill in the art that the idealized reaction mixtures presented above contain a variety of components, such as salts and buffers, for which ready substitutions are possible. It is also apparent that these reaction mixtures are calculated for certain total reaction volumes, and that the concentrations and amounts would be varied for a different volume of reactions.
EXAMPLES
Transcription Time Course
A series of experiments of the transcription reaction, with translation begun at various incubation times, were undertaken with the transcription reaction mixture and the translation reaction mixture as described above. The DNA template used for this reaction was the STP control template (E. coli β-galactosidase in a pCITE® vector) and the RNA polymerase used was the T7 RNA polymerase. All reactions were performed at 30° C. and in the presence of 3 H-CTP. At time intervals from initiation of the transcription reaction, two microliter aliquots were removed from the reaction mixture for measurement of the total RNA synthesis by TCA precipitation. Duplicate 10 microliter aliquots were added to 40 microliter translation mix containing 35 S-methionine and incubated at 30° C. for an additional 90 minutes. The amount of protein synthesized was quantitatively analyzed using the S-Tag Rapid Assay Kit (Novagen) which allows for the non-radioactive assay of quantitative amounts of protein translated in vitro. The S-Tag sequence is a 15 amino acid leader peptide which, when present in a translated protein, can be detected using the S-Tag Rapid Assay Kit. The amount of protein production was also verified by radiographic analysis of 35 S-labeled β-galactosidase following SDS gel electrophoresis.
The results of these experiments are illustrated in FIGS. 1 and 2. FIG. 1 illustrates the time course for transcription. The data demonstrate that transcription is 80% complete within 10 minutes at 30° C. The translation data, shown in FIG. 2, provide a similar conclusion in that almost all of the translatable mRNA was synthesized within the first 15 minutes of transcription.
Effect of Magnesium Concentration
The procedure of the present invention was performed under standard conditions, with the transcription reaction mixture and the translation reaction mixture described above using three template DNAs. One template DNA is the vector pCITE, which includes a phage promoter and a cap independent translation enhancer sequence driving a coding region which, in this instance, was the enzyme β-galactosidase. A second template was the vector pET CRE which is a pET vector (Novagen) containing the gene for bacteriophage P1 cre recombinase. The third template used was a pGEM (Promega) vector into which had been inserted a gene coding sequence for the firefly luciferase protein.
All three plasmids were introduced into 10 microliters of the transcription reaction mixture described above. Following incubation for 15 minutes at 30° C., 40 microliters of the translation mixture was added to the vessel. The translation mix contained 35 S-methionine and varying amounts of magnesium acetate, either 1, 1.5, or 2.5 mM. All three templates produced optimal translation in the presence of approximately 1 mM magnesium acetate under standard conditions, as determined by fluorographic analysis of SDS-PAGE gels. The amount of protein synthesis markedly declined at a concentration of 2.5 mM magnesium acetate. Additional experiments performed under similar conditions demonstrated that magnesium concentrations below 0.8 mM also result in lower translation efficiency for all three templates. These data indicate that the most efficient translation of all template types occurs at a magnesium concentration in the range of 1 mM in the final mix of transcription and translation mixtures.
To investigate the efficacy of this protocol with a wide variety of DNA templates, several plasmid and PCR template DNAs were created and then used as a template in the dual stage reaction described herein. Two of the templates were prokaryotic proteins, including E. coli β-galactosidase and P1 cre recombinase. Several eukaryotic protein sequences were used as well, including firefly luciferase, mouse tropomyosin, a recombinant antibody construct, and encephalomyocarditis VPO protein. Again the production of protein was visualized and quantified by SDS-PAGE electrophoresis and fluorography. One class of templates which proved to be particularly efficiently translated were the templates carrying the CITE sequence of the EMC enhancer. However, all templates were transcribed and translated with efficiency. The PCR amplification products, containing upstream T7 promoter with or without a CITE sequence, also served as efficient templates for protein production. The same PCR templates produce little or no protein when added to another commercially available reticulocyte lysate based transcription/translation system. This demonstrated that the transcription and translation method of the present invention is applicable to a wide variety of DNAs and PCR transcription products without particular specificity to any given template.
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A method for performing coupled in vitro transcription and translation reactions is disclosed. In the transcription reaction, the quantity of mRNA produced is limited to a level of less than about 2.5 micrograms in a 10 microliter volume prior to the translation elements being added. Limiting the level of mRNA produced prevents saturation of the translational processes and thus aids in the efficiency and fidelity of the translation process.
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RELATED APPLICATION
This application is a Division of co-pending U.S. patent application Ser. No. 15/409,998, filed 19 Jan. 2017.
BACKGROUND OF THE INVENTION
This invention relates to a modular and flexible cargo net system and improvements to associated components, such as ratchet straps and ring connections. The invention is particularly suited for situations where it is desirable to secure a carried load, for instance (but not limited to) in a bed of a truck.
SUMMARY OF THE INVENTION
A magnet grip cargo net system is disclosed. An anchor strap is provided, and a loop with a plurality of engagement rings. A ring is placed about a first end of a webbing strap, and the first end of the webbing strap is threaded through an anchor, for instance in a truck bed. An additional ring is placed about the webbing on a second side of the anchor. The first end of the webbing strap is placed through a second anchor, and a third ring is placed about the first end of the webbing strap. The first end of the webbing strap is then threaded through the second ring and into a ratchet mechanism which is subsequently tightened.
A plurality of s-hooks (preferably magnetic, for instance as disclosed in U.S. Pat. No. D765,498) carrying additional webbing are placed into each ring, A plurality of straps are anchored to the truck bed anchor system and a grid of straps is created.
A plurality of straps are woven through a series of rings laid atop webbing strap. The webbing is threaded over the ring, under the webbing, and then up through the ring again and through, loosely securing the rings to the lateral webbing. Preferably the ring is placed atop the anchor webbing to avoid damaging a load carried beneath the webbing.
A webbing lattice is created that is adjustably tightened to secure a load.
The rings can be slidably adjusted across the webbing for customized load securement.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a rear perspective, in-use view of a cargo net system of the present invention;
FIG. 2 is a side view of a carrying case dimensioned to store the cargo net system of the present invention;
FIG. 2A is a perspective view of an exemplary series of rings carried by a ring carrying strap of the present invention;
FIG. 3 is a top view of front and rear anchor straps of the cargo net system of the present invention;
FIG. 3A is a side view of a single strap webbing through a pair of rings, and a double strap webbing through a center ring of the system;
FIG. 4 is a top view of anchor and cross straps of the cargo net system of the present invention;
FIG. 5 is a close-up view of hooks and webbing coupled to a truck bed anchor system;
FIGS. 6A-6C are close-up in-sequence views of installation of a webbing lattice about anchor straps and rings of the present invention;
FIG. 7 is a perspective view of an improved D-ring of the present invention carried by a ratcheting strap system;
FIGS. 8A-8C are views of an improved D-ring of the present invention;
FIG. 9 is a top view of an improved D-ring of the present invention carried by a ratcheting strap system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
Referring now to FIG. 1 , a rear perspective, in-use view of a cargo net system 10 of the present invention is shown, carried for exemplary purposes in a bed of a truck 8 . A series of anchor straps 12 are provided about the bed of truck 8 , secured preferably to truck anchors 20 commonly present in truck beds. Together with interconnected lateral straps 26 , anchor straps 12 provide a flexible, portable and modular cargo netting system as a webbing lattice for example.
In a preferred embodiment, anchor straps 12 and lateral straps 26 comprise a ratcheting mechanism 14 for securement to the truck 8 and about a cargo load (not shown) as tight as desired.
Referring now to FIG. 2 , a carrying case 24 dimensioned to store the cargo net system 10 of the present invention can be provided.
As shown in FIG. 2A , a series of rings 16 , the use of which will be described later, are removably carried by a ring strap 22 .
As shown in FIG. 3 , a top view of front and rear anchor straps 12 of the cargo net system 10 of the present invention are shown. In a first cargo net system 10 installation step, now with reference to both FIGS. 1 and 3 , a bottom anchor strap 12 is provided toward a front of the truck bed, at a low position in the bed. At least one ring 16 is provided about at least one strand of bottom anchor strap 12 . This anchor strap 12 can either be coupled to truck anchors 20 either be threading a free end of anchor strap 12 through truck anchors 20 on both sides of the truck 8 , or by securing s-hooks 19 (preferably magnetic) about truck anchors 20 (See, e.g., FIG. 5 ). A bottom anchor strap 12 is also preferably provided toward a rear of the truck bed, again at a low position in the bed.
Next, a series of upper anchor straps 12 are preferably provided toward the front, middle and back of the truck bed laterally crossing at least a portion of the bed, this time at a high position in the bed. Again, these anchor straps 12 can either be coupled to truck anchors 20 either be threading a free end of anchor strap 12 through truck anchors 20 on both sides of the truck 8 , or by securing s-hooks 19 (preferably magnetic) carried by straps 12 about truck anchors 20 .
In a preferred embodiment as shown in FIG. 3A , a side view of a single strap webbing 12 is shown through a pair of rings 18 , both left and right of a two scraps of webbing 12 through a center ring 18 of the system. This configuration is preferably used to assist the stability and equalization of the load weight on the anchor straps 12 .
As shown in FIG. 4 , a grid of anchor straps 12 and lateral straps 26 is created by coupling straps 26 to straps 12 from the front to the back of the cargo bed to create a flexibly sized and configured cargo securement lattice. In this step, S-hooks 18 carried by lateral straps 26 are first coupled to the front bottom anchor strap 12 about the rings 16 carried by front bottom anchor strap 12 , and then fed first vertically to front top anchor strap 12 , and referring now to the sequence shown in FIGS. 6A-6C , in-sequence views of installation of a webbing lattice of lateral straps 26 about anchor straps 12 and rings 16 of the present invention are shown. First, rings 16 are placed atop straps 12 , and a free end of lateral strap 26 is threaded over a first portion of ring 16 , next under anchor strap 12 , and then up through ring 16 , and the free end of lateral strap 26 is slidably advanced as shown in FIG. 6B , and pulled taut as shown in FIG. 6C . This sequence is repeated for as many lateral straps 26 as desired, e.g., for three lateral straps 26 about three anchor straps 12 , as shown in FIG. 4 . Of course, more or less scraps 12 or 26 can be used according to user preference. Last, s-hooks 18 carried by lateral straps 26 are fed downward vertically and coupled to the rear bottom anchor straps 12 about the rings 16 carried by front bottom anchor strap 12 . Additional ratcheting mechanisms 14 can then be employed to tighten the straps 12 and 26 of the system as desired. Alternatively, lower anchor strap 12 of FIG. 5 could alternatively be provided with a hook 18 as opposed to threaded webbing 12 as shown.
Rings 16 can be slidably positioned laterally about either of straps 12 and 26 for adjustability of the system 10 .
Referring now to FIG. 7 , and FIGS. 8A-8C an improved ratcheting strap system 14 of the present invention is shown. Namely, referring now to FIG. 9 , D-ring 28 carrying a hand operated pull strap 34 is coupled to a pull bar 50 of ratcheting mechanism 14 to release tension on the ratcheting mechanism 14 . A D-ring pivot plate a pivotally carries a ring of D-ring 28 , and a D-ring pivot plate securement hole 32 is provided to couple the D-ring 28 to a solid portion of ratcheting mechanism 14 .
The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
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A cargo containment system is disclosed comprising a series of length adjustable anchor straps carried by a truck, a series of rings slidably carried by said anchor straps, and a series of length adjustable lateral straps coupled between adjacent anchor straps about said rings to define an adjustable flexible lattice of cargo containment function.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to implantable cardiac stimulation devices and systems for regulating the contraction of a heart. More particularity, the invention relates to a defibrillation lead, and more particularly to a defibrillation lead having multiple lumens therein and to a method of manufacturing for such leads.
2. Description of the Related Art
Implantable medical devices for treating irregular contractions of the heart with electrical stimuli are well known in the art. Some of the most common forms of such implantable devices are defibrillators and pacemakers.
Defibrillators are implantable medical devices used to treat fibrillation, a condition characterized by rapid, chaotic electrical and mechanical activity of the heart's excitable myocardial tissue that results in an instantaneous cessation of blood flow from the heart. Defibrillation is a technique employed to terminate fibrillation by applying one or more high energy electrical pulses to the heart in an effort to overwhelm the chaotic contractions of individual tissue sections and to restore the normal synchronized contraction of the total mass of tissue.
A pacemaker, or pacer, is an implantable medical device that delivers low energy electrical pulses to stimulate a patient's heart to beat at a desired rate in instances where the heart itself is incapable of proper self-regulation. This occurs when the heart's natural pacemaker, which causes the rhythmic electrical excitation of the heart and pumping of blood, malfunctions due to age or disease. Demand pacing is a process used to maintain normal beating of a heart having this condition.
Various types of leads for defibrillators and demand pacers have been suggested in the prior art. For example, large electrical patches sewn to the exterior surface of the heart have been used to deliver defibrillation pulses to the heart. Implantation of such patch electrodes requires opening of the patient's chest during thoracic surgery. For pacing, pulses may be applied to the heart with the use of a pacer lead having an exposed metal surface, or demand pacer electrode, extending through a vein and into the heart.
Those involved in the medical arts recognized that prior art defibrillators required a high threshold level of energy for effective defibrillation, which limited the useful life-span of the devices and, more significantly, posed a significant risk of causing electrolysis of the blood and myocardial damage. It was realized that the defibrillation electrode configuration played an important role in the amount of energy needed to achieve successful defibrillation. This led to the development of transvenous defibrillation leads having long coil-shaped defibrillation electrodes for implantation into the right ventricle of the heart through a vein. For example, U.S. Pat. No. 4,922,927, the entire disclosure of which is incorporated herein by reference, discloses a defibrillation electrode made up of a plurality of separate wires wound side-by-side to form a tight coil. The coil was disposed upon an insulated tubular member and had a length sufficient to extend throughout the entire length of the ventricular chamber to provide sufficient electrode surface area for defibrillation.
Transvenous cardiac stimulation leads, such as the device of U.S. Pat. No. 4,922,927, were configured to also carry a demand pacing electrode. Thus, a single device implantable in one surgical procedure could provide defibrillation and pacing pulses for heart patients suffering from both irregular heart beat and, at times, cardiac fibrillation. This eliminated the need for multiple and complex surgical procedures to attach the prior art electrodes required for both types of treatments.
Another defibrillation electrode configuration for use with dual purpose transvenous leads is disclosed in U.S. Pat. Nos. 5,476,502 and 5,374,287 to Rubin, which are also incorporated herein by reference in their entireties. The “Rubin” catheter included either a helical or lance shaped defibrillation electrode for delivering a defibrillation pulse directly to the interior of the septum of the patient's heart. The length of the helix-shaped electrode to be screwed into the septum from the right ventricle, about 0.5 cm to 1.0 cm, was substantially shorter than the conventional coiled transvenous defibrillation electrodes.
Despite these developments there continues to be a need for a lead capable of providing both high voltage defibrillation and effective demand pacing with a smaller lead diameter to minimize obstruction in the veins leading to the heart. One such lead has been developed by some of the inventors herein and others. A commonly-assigned patent application has been filed entitled Endocardial Defibrillation Lead with Looped Cable Conductors, attorney docket no. ITM-609 US, the disclosure of which is incorporated herein by reference. This lead has a looped cable conductor for conducting high voltage defibrillating shocks to the heart and a coil conductor for conducting low voltage pacing pulses. These two conductors are carried in separate lumens within a lead body. Additional lumens may be provided for additional conductors, if additional functions are desired. The conductors are connected to pacing or defibrillation electrodes or to sensors or other devices at selected locations along the length of the lead body. To connect the electrodes or other devices to a conductor, it is frequently necessary to cut a window through the lead body to gain access to a selected lumen. Because lead bodies are often made of silicon rubber and are very flexible, it is difficult to make these windows in a replicable fashion.
SUMMARY OF THE INVENTION
We have invented an implantable defibrillation lead with an elongated, flexible lead body having multiple lumens and windows at selected locations along the lead body, the windows providing access to selected lumens. We have also invented a method of manufacturing such leads and an apparatus for performing this method. According to our invention, a jig with an electromagnetic table supports a lead body. A ferromagnetic stylet, inserted in a selected lumen of the lead body orients the lead body in the jig when the lead body is placed within the magnetic field of the electromagnet. Mechanical grinding wheels then remove material at selected locations to form the windows. Alternatively, a punch could also form the windows.
In a preferred embodiment, there is provided an implantable endocardial defibrillation lead having a looped cable conductor for conducting at least high voltage defibrillation shocks. A coil electrode is connected to an elongated, flexible, electrically non-conductive lead body and is supplied with electrical power for delivering electrical shocks to the heart through a looped cable conductor that extends through the lead body and is associated with a power source.
Depending upon the desired application for the lead, the invention may also be used with a pacer and, thus, include any of a variety of pacer electrodes and sensors that are presently available or may become available. Such devices, if used, would be disposed upon the lead, insulated from the defibrillator electrode segments and electrically connected with a second electrical conductor that extends through the lead body and provides electrical power to the pacer electrode. The lead may also include a ground electrode disposed upon the lead a distance from the other electrodes to receive the pulses delivered to the heart tissue and transmit them back through a third electrical conductor extending through the lead. The coil electrode and looped cable conductor may also serve a dual function as a ground electrode and conductor.
The invention may also be adapted for fixation of the distal end of the lead to the heart to achieve selective positioning of the electrode or electrodes. A variety of currently available passive and active fixation mechanisms, or that may become available, may be used with the invention. In one embodiment of the invention, the lead includes tines. A small fixation screw for securing the distal end of the lead within the heart, wherein the fixation screw also functions as a pacer stimulating and sensing electrode, could be used.
The characteristics and advantages of the present invention described above, as well as additional features and benefits, will be readily apparent to those skilled in the art upon reading the following detailed description and referring to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings wherein:
FIG. 1 is a plan view of an implantable defibrillation and pacing lead.
FIG. 2 is a perspective view of a cable conductor used in the lead.
FIG. 3 is a partial section of a distal end of the lead of FIG. 1 with a window for allowing connection of a cable conductor to a defibrillation electrode.
FIG. 4 is a plan view of the assembled inner sleeve and cable conductor at the window.
FIG. 5 is a through section of the window of FIG. 4, taken along line 5 — 5 .
FIG. 6 is a partial through section of the proximal end of the lead.
FIG. 7 is a perspective view of an apparatus for manufacturing windows in lead bodies according to the present invention.
FIG. 8 is a cross sectional view of a multilumen lead and ferromagnetic stylet according to our invention.
FIG. 9 is a cross sectional view as in FIG. 8, showing two magnets.
FIG. 10 is a cross sectional view as in FIG. 8, showing a punch.
FIG. 11 is a cross sectional view as in FIG. 8, showing two cutters.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The presently preferred embodiment of the invention are shown in the above-identified figures and described in detail below. In describing the preferred embodiments, like or identical reference numerals are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic form in the interest of clarity and conciseness.
FIG. 1 illustrates a plan view of an endocardial high voltage cable lead 14 . A ventricular tip cathode or electrode 22 and shock coil 24 are located at distal end 44 of the lead 14 . At a proximal end 46 of the lead there is a high voltage connector 48 and a low voltage connector 50 , preferably an IS-1 (international standard one) connector. The two connectors 48 , 50 are joined at a junction 52 which is covered by an insulative boot 54 . A lead body 56 extends between the distal end 44 and the proximal end 46 . A suture sleeve 58 is slidingly received on the lead body 56 and conventionally provides additional support for the lead 14 where it is inserted in a blood vessel of a patient. At the tip cathode 22 , tines 60 may be provided to help secure the lead 14 within the heart. Other well known active or passive fixation devices, such as helical screws, may be provided. Such features are well known in the art and need not be further described herein.
The shock coil 24 comprises a segment 62 of coiled wire, preferably multi-filar, more preferably tri-filar. A distal cap 64 secures one end of the segment 62 , while a proximal sleeve 66 secures the other end. More detail concerning the shock coil 24 will be provided hereafter.
Regarding the proximal end 46 of the lead 14 , the low voltage connector 50 is provided with annular sealing rings 68 , 70 to prevent body fluids from injuring the connector, when the connector is inserted into the implantable device. Between the sealing rings 68 , 70 , a lead connector 72 may be provided. A pin connector 74 is located at the proximal end of the lead, thus providing two electrical contacts for the low voltage connector 50 . Through these connectors 72 , 74 , the electrical condition of the heart may be sensed, particularly of the ventricle, if the distal end of the lead 14 is implanted therein. In addition, pacing pulses and other low voltage therapy may be provided through these connectors to the tip cathode 22 . As will be more fully explained below, the shock coil 24 may be used as a low voltage anode or indifferent electrode if bipolar sensing or pacing is desired. Alternatively, a conventional low voltage ring electrode could be provided near the distal end of the lead.
The high voltage connector 48 also has annular sealing rings 76 , but is usually provided only with a pin connector 78 . The electrical path for high voltage shocks is usually between this pin connector 78 through an electrical conductor to the shock coil 24 and back through the heart to a can of the implantable medical device (not shown). However, an additional coiled electrode could be provided, forming a bipolar shock electrode. Where two coiled shock electrodes are used, they are frequently placed on the lead such that one would be in the ventricle and the other in the atrium or superior vena cava. Multi-filar coiled connectors have heretofore been used to conduct the electrical current for the shock to one or more shock coils.
In a preferred embodiment, a looped cable conductor is provided. The cable conductor 80 is illustrated in prospective view in FIG. 2 . The cable conductor 80 comprises a conductive multi-strand wire 82 . Preferably, most of the wire 82 has insulation 84 . A middle section of the wire 86 is stripped of insulation, and then the cable conductor is folded back on itself, forming a loop or bend 92 at the middle section 86 . Each end 88 , 90 , of the conductor is also stripped of insulation. As a consequence of the looped construction described, the conductor 80 forms a redundant system, as either side of the conductor is capable of carrying current to the shock coil 24 .
We will describe the distal end 44 of the lead 14 in greater detail, in connection with FIG. 3 . FIG. 3 is a partial through-section of the distal end 44 . As can be seen in FIG. 3, the tip cathode 22 comprises a shank 94 which extends into the distal cap 64 , and into the lead body 56 . The tines 60 are formed on the distal cap 64 . In addition, the distal cap 64 captures a distal end 112 of the coil segment 62 . Within the shank 94 , a stopped bore 96 receives a crimp plug 98 and a coil conductor 100 . The coil conductor 100 is a conventional low voltage conductor which extends from the tip cathode 22 to the pin connector 74 and electrically couples the cathode 22 and the pin connector 74 . The shank 94 is crimped over the crimp plug 98 to secure the conductor 100 between the crimp plug and the shank.
The coil conductor 100 passes through a first lumen 102 in the lead body 56 . Preferably this lumen is non-coaxial, that is, it is offset from the axis of the lead body 56 . However, to receive the shank 94 symmetrically with respect to the lead body, a stopped bore 104 is provided in the distal end of the lead body. This stopped bore is coaxial with the axis of the lead body itself. A second lumen 106 is provided to receive the looped cable conductor 80 . Preferably, this lumen is also non-coaxial with respect to the lead body and may be smaller in diameter than the first lumen 102 . Additional lumens may be provided where additional looped cables are connected to other electrodes, such as a second shock electrode.
A window 108 is cut through a portion of the lead body 56 to expose the second lumen 106 . An apparatus and method for forming this window will be further discussed below. An arcuate crimp sleeve 110 fills this window 108 and captures the stripped middle section 86 of the cable conductor 80 . A proximal end 114 of the coil segment 62 extends over the arcuate crimp sleeve 1 10 and is covered by the proximal sleeve 66 . This proximal end 114 preferably extends for a plurality of loops proximal to the arcuate crimp sleeve; preferably two loops. In multi-filar coils, each filar should form the loops proximal to the arcuate crimp sleeve. This extension proximal to the crimp sleeve relieves mechanical stresses, and reduces the possibility of a mechanical failure adjacent the crimp sleeve. A circumferential bead of adhesive 116 seals the distal cap 64 to the coil segment 62 and underlying lead body 56 . A similar adhesive bead 118 likewise seals the proximal sleeve 66 to the coil segment 62 and lead body 56 .
Further detail of the window and lumens can be seen in FIGS. 4 and 5. FIG. 4 is a top plan view of the window 108 with crimp sleeve 110 , with the cable conductor 80 shown in phantom lines. FIG. 5 is a plan through section of the multilumen lead body.
Once the crimp sleeve 110 has been positioned in the lead body, the proximal sleeve 66 can be slid onto the lead body. The coiled segment 62 is then placed on the lead body with the proximal end extending past the crimp sleeve 110 . The coil 62 is then laser welded to the crimp sleeve. The proximal sleeve 66 is brought up over the proximal end of the coil 62 and secured with adhesive, as described above.
The proximal end 46 of the lead is shown in FIG. 6, showing a partial through section of a plan view of the distal end 46 of the lead. The boot 54 encloses an assembly connecting the two connectors 48 , 50 . A crimp connector 136 is connected to a coiled conductor 138 which is electrically and mechanically connected to the pin connector 78 of the high voltage connector 48 . The coil conductor 138 passes through an insulating sleeve 140 . The low voltage connector 50 has a coaxial lead segment 142 . The coil conductor 100 , described above in connection with the distal end of the lead, passes co-axially down the lead segment 142 , that is, the axis of the coil 100 and the axis of the lead segment 142 coincide. An inner tubing 144 surrounds the coil conductor 100 . A return low voltage coil conductor 146 surrounds the inner tubing 144 and is connected proximally at one end to the ring connector 72 and at a distal end 150 to the crimp connector 136 . An outer tubing 148 encases the return coil 146 .
We will now describe an apparatus for preparing a window in the lead body 56 . A cutting apparatus 150 is illustrated in perspective view in FIG. 7. A jig 152 is mounted on a base plate 153 . The jig 152 has a sliding table 154 which holds a support beam 156 by means of end brackets 158 , 160 . Machine screws 162 fasten the end brackets 158 to the table 154 . Machine screws 164 connect the support beam 156 to the end brackets 158 . A groove 166 runs longitudinally along the support beam 156 for receiving and supporting a lead body 56 . Magnets 168 are mounted in the support beam 156 to attract a ferromagnetic stylet inserted in a lumen in the lead body. These magnets 168 are preferably fixed magnets but may also be electromagnets. Suitable fixed magnets are rare earth magnets available from Duracore. A back plate 170 mounted on the support beam 156 helps to prevent the lead from being displaced by the action of end cutter used to make a window in the lead body. In the illustrated embodiment, a slot 172 allows the cutter to pass through the back plate 170 during the cutting operation.
Two ball bearing slides 174 , 176 support the table 154 which is fastened thereto by machine screws 177 . The ball bearing slides 174 , 176 are free to reciprocate smoothly between pillow blocks 178 , 180 , 182 , 184 which support respective pairs of slide rods 186 , 188 and 190 , 192 . The ball bearing slides 174 , 176 enable the jig 152 to be moved smoothly in a first linear direction which we will call the Z direction. This movement brings the lead body 56 into contact with a grinding wheel 200 . The position of the grinding wheel 200 can be adjusted in two other mutually orthogonal directions which we will call X and Y directions, thus providing a complete range of adjustment for making the required window in the lead body 56 . In our preferred embodiment, this cutter comprises a grinder 194 . The grinder 194 comprises a grinder motor 196 which turns a shaft 198 . The grinding wheel 200 is mounted on the end of this rotating shaft 198 . The motor is supported by a motor mount 202 which has a horizontal micrometer 204 for adjusting the position of the grinding wheel 200 in the X or horizontal direction. A vertical micrometer 206 is also provided for adjusting the position of the grinding wheel 200 in a vertical or Y direction. A base 208 is fastened to the horizontal micrometer 204 and supports an upright mounting plate 210 . In its turn, the upright mounting plate 210 supports the vertical micrometer 206 which is attached to the motor 196 . As a safety feature, a shield 214 is mounted to a shield bracket 212 which shield bracket is also connected to the motor 196 . A live center 216 rides against the end of the shaft 198 to reduce vibration.
In operation, a lead body is placed in the groove 166 . The position of the grinding wheel 200 is carefully adjusted using the horizontal and vertical micrometers 204 , 206 . With the grinding wheel spinning 200 , the table supporting the support beam 156 slides horizontally in the Z direction, thus causing the lead body 56 to pass under the grinding wheel 200 and cutting the desired window in the lead body. The lead body is properly oriented by the action of the magnets 168 on the ferromagnetic stylet in the lead body 56 .
This can be seen more clearly in FIG. 8 which shows a lead body 56 in cross section mounted on the support beam 156 . The ferromagnetic stylet 220 is in the first lumen 102 . The second lumen 106 is oriented properly by action of the magnet 168 on the ferromagnetic stylet 220 . Sliding the table 154 in the Z direction shown brings the lead body 56 into contact with the grinding wheel 200 , cutting the window 108 .
An alternative configuration is illustrated in cross section in FIG. 9 . In FIG. 9 the lead body 56 is shown oriented toward the magnet 168 by magnetic action on the ferromagnetic stylet 122 such that the second lumen 106 may be cut by the cutter. A second magnet 222 is also provided. This magnet 222 is preferably an electromagnet connected to a power supply 224 . Of course, electromagnets could be used for both first and second magnets. When the electromagnet 222 is activated, the ferromagnetic stylet 220 responds to both magnetic fields and readjusts the position of the lead body 56 such that a third lumen 107 can be cut. Of course, if an electromagnet is also used for the first magnet 168 , that magnet may be turned off when the second magnet 222 is turned on.
It will be recognized that other types of cutters may be used in place of a grinder wheel 200 . For example, a punch 226 or knife edge could be utilized as illustrated in FIG. 10 . In addition, multiple cutters could be utilized as illustrated in FIG. 11 . The cutters may be made movable rather than the table 154 , allowing windows to be cut in different lumens without reorienting the lead body 56 . Alternatively, it may be desired to cut more than one window into the same lumen. Multiple parallel cutters would allow such an operation to be done in a single step.
Those skilled in the art will recognize from the foregoing description that the multilumen lead with windows of our invention can be used in cardiac leads in other configurations without departing from the teachings of our invention. For example, more then one looped cable conductor could be provided for bipolar defibrillation shocks. Low voltage connections could be provided to some, all or none of such looped cable conductors.
While preferred embodiments of the present invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit or teachings of this invention. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of this system and apparatus are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims which follow, the scope of which shall include all equivalents of the subject matter of the claims.
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An implantable endocardial defibrillation lead having an elongated lead body with multiple lumens therein. Windows, cut through the lead body, provide access to selected ones of the lumens at selected locations along the lead body. In addition, a method and an apparatus for forming windows in a multilumen lead body are disclosed. A ferromagnetic stylet is inserted into a selected lumen. The lead body is oriented in a jig by application of an electromagnetic field. A grinder or punch cuts a window into the selected lumen.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a memory error correction technique, and pertains, more particularly, to a technique for correcting correctable errors by recycling data that has been corrected by the memory error correction logic back into memory in order to clean up memory errors and, in particular, alpha particle (soft) failures.
2. Background Discussion
When a correctable error (CE) occurs in a memory, and, in particular, in association with dynamic random access memories (DRAMs), it is desirable to send the corrected data back into the memory to correct the failure, so that the probability of an uncorrectable error (UE) occurring is reduced. This involves the correcting of the correctable error by the error correcting code hardware, and, in addition, providing the corrected copy to the requesting processor and writing the corrected data back into the memory location from which it was read. This serves the purpose of "cleaning up" the error if it was a soft (alpha particle) error.
In one previous system, the memory controller accomplished this by placing the corrected data into a reserved location in the write buffer and setting the write pending bit. This causes the memory controller to treat this location in the write buffer as data that is to be written back into the memory DRAMs.
Present, larger capacity memory systems are different from previous memory systems in that while previous memories performed read or write on a maximum of 64 bits (78 bits including the error correcting code), present memory systems deal with as many as eight times this much information (eight double words or 512 bits or, alternatively, 576 bits with the error correcting code). Thus, due to this increased hardware requirement, the present storage control unit does not contain a write buffer in the traditional sense. Only addresses are buffered at the storage control unit and there is no provision for buffering groups of 576 bits. Rather, data is "staged" in a fetch pipeline. A "fetch pipeline" is a logic arrangement that holds data in a fetch data path while waiting for the system bus.
Because of the short cycle time of modern machines, and because of the many functions that need to be performed in the memory subsystem on fetch data, a fetch pipeline which operates like a CPU pipeline is implemented in order to hold the eight double words of fetch data on a read operation while the storage control unit is waiting to be granted use of the system bus (SYSBUS). Clearly, with this type of architecture, the previous method of recycling data employing a write buffer on a correctable error is not usable.
Accordingly, it is an object of the present invention to provide an improved system for memory error correction and, in particular, for correction of alpha particle type (soft) memory failures.
Another object of the present invention is to provide a memory error correction system for use in a system wherein the various processors employ writeback caches.
SUMMARY OF THE INVENTION
To accomplish the foregoing and other objects, features and advantages of the invention there is provided an improved technique for correcting memory errors and, in particular, correctable types of errors such as alpha particle (soft) memory errors or failures. The concepts of the present invention are preferably employed in a memory controller system not having a write buffer but wherein there are preferably provided writeback caches in a system bus environment. The writeback caches in this type of system are able to respond to read requests from other devices. Therefore, while the data was recycled entirely within the memory subsystem previously through the use of the write buffer, the solution of the present invention takes advantage of the capability of writeback caches in the system to respond to read requests. Thus, the memory controller functions like other devices on the system bus, requesting data to be sent back to it by making a read request whenever a correctable error occurs. Hence, the technique of the present invention is more of a system solution to the recycling problem and is geared preferably toward systems with writeback caches. On the other hand, the write buffer technique is a memory-only solution.
In accordance with the system of the present invention, there is a storage control unit for controlling the transfer of data from a system bus to an array control unit and associated memory array. If a correctable error is detected by the storage control unit, while data is being transferred out onto the system bus, the fetch sequencer of the storage control unit causes a generic message request signal to be encoded on the bus request lines to the bus control unit, and on a prioritized basis, a bus grant occurs and the storage control unit renders a read CE (correctible error) message out onto the system bus. The generic message request represents a group of miscellaneous requests such as invalidation, sending machine check modes, and read CE requests. The storage control unit makes the destination ID and the address fields of this message to be identical to the source ID and address fields of the read message upon which the CE occurred. This special read message is different from other read messages in that it is device specific; that is, only the device whose device ID matches the destination ID responds to the read request. Thus, when the device which just received the read data on which the CE occurred sees this message on the system bus, it performs a writeback of a block of data back to the memory subsystem over the system bus, cleaning up the soft error in memory.
In accordance with a further aspect of the present invention, there is also disclosed herein an improved method of correcting memory errors, which method is practiced in a computer system having a central processing unit, I/O processing unit, a memory, a memory control unit, a systems communication bus and a bus control unit. This method comprises the steps of detecting a data error while data is being transferred from memory to the system bus and storing at the memory control unit at least the address field and source identification code associated with the just detected data error. A next step is the generating of a bus request signal coupled to the bus control unit. The bus control unit, in turn, generates a bus grant signal on a prioritized basis. The memory control unit in response to the bus grant signal issues a read CE message on the system bus having an address field and destination identification code corresponding to the stored address field and source identification code. In response to the read CE message, the device indicated by the identification code writes back to memory the correct data corresponding to the address field.
BRIEF DESCRIPTION OF THE DRAWINGS
Numerous other objects, features and advantages of the invention should now become apparent upon a reading of the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a general block diagram of a memory system as in accordance with the present invention; and
FIG. 2 describes the further details of the storage control unit of FIG. 1.
DETAILED DESCRIPTION
In connection with a further description of the concepts of the present invention, reference may be now made to the general block diagram of FIG. 1 for an illustration of the basic components comprising the memory error correction system. FIG. 1 illustrates the system bus 10 and associated acknowledgment bus 12, also referred to hereinafter as the ACK/NACK bus 12. FIG. 1 also illustrates the various processors and subsystems that interface with the system bus 10 and bus 12. For the purpose of illustration in FIG. 1, there are shown the I/O processors 14 and CPU (central processing unit) 18. FIG. 1 also illustrates the storage control unit 20 that intercouples between the system bus 10 and the array control unit 22 and a memory array 28. Finally, FIG. 1 also discloses the bus control unit 34.
In the block diagram of FIG. 1, many of the components and associated operations thereof are conventional and they are thus not described in any great detail. For example, the bus control unit 34 may be substantially of conventional design including prioritizing arbitration logic 36. Also, the array control unit 22 may be considered as being of substantially conventional design including data input registers 23, data output registers 24 and array control logic 26. The array control logic 26 generates such well known memory control signals as the signals RAS, CAS and WE. Likewise, the memory array 28 includes a dynamic random access memory array 29 with associated data registers 30 and 31, register 30 being an input data register and register 31 being an output data register. Within the memory array 28, there is also disclosed the box 32. This may be comprised of a series of registers and drivers for control and addressing of the array 29.
At the processor end of the system, as indicated previously, there is illustrated in FIG. 1 two I/O processors 14 and CPU 18. Each of these processors has a cache memory which is a writeback cache. As far as the I/O processors are concerned, this is illustrated in FIG. 1 by the cache control 15 and cache data 16. Similarly, the CPU 18 has a writeback cache illustrated by the cache control 17 and cache data 19. As far as the storage control unit 20 is concerned, reference is made hereinafter to the more detailed block diagram of FIG. 2 for further details of the storage control unit. It is the storage control unit 20 that is primarily designed for use of the concepts of the present invention, particularly as it interrelates with the bus control unit 34.
The system bus 10 in the embodiment described is a 72 bit multiplexed message and data bus and also includes as part thereof a three bit valid message bus. The valid message bus serves to qualify whether a message, data or nothing is on the 72 bit bus at any given bus cycle. In addition, there is illustrated the two bit ACK/NACK bus 12. This is used to inform the sender of a system bus message whether or not the required action has been performed in response to the message or not. In actual implementation, this bus may be 4 bits wide but is shown herein in its simplified form for the purpose of clarifying the description.
The bus control unit 34 controls the usage of the system bus 10. In this regard, and as illustrated in FIG. 1, the arbitration logic 36 of the bus control unit 34 receives four bit bus requests from each device which attaches to the system bus and provides a single bit bus grant line to the device with the highest priority bus request. In this regard, in FIG. 1, note the 4 bit inputs from devices and the single bit outputs indicating a bus grant. Also note that a bus request is coupled from the storage control unit 20 and likewise a single bit bus grant line couples back to the storage control unit from the arbitration logic 36.
As indicated previously, the memory subsystem is basically comprised of a storage control unit 20, an array control unit 22, and the memory array 28. The memory array 28 contains the dynamic RAM chips used for storage as well as registers and drivers. The array control unit 22 generates the array control signals previously referred to RAS, CAS, WE needed to read, write and refresh the DRAM array 29. The array control unit 22 also registers the fetch and stored data between the storage control unit 20 and the memory array 28.
Now, reference is made to the more detailed block diagram of the storage control unit 20 as illustrated in FIG. 2. The storage control unit 20 includes a transceiver box 38 which is the basic element interfacing directly with the system bus 10. In this regard, note the direct connection at the 72 bit message/data bus and 3 bit valid message bus. The system bus transceivers 38 include also multiplexers and registers. The box 38 contains bidirectional transceivers, input and output registers and multiplexers for messages and data sent by the storage control unit 20 onto the system bus 10.
There is also described the valid message logic 40 shown having a three bit line connecting with the system bus transceivers 38. The valid message logic 40 decodes the valid message bus when the storage control unit 20 is not using the system bus, it also creates the proper code for messages and data sent by the storage control unit 20 onto the system bus 10.
The logic box 42 is appropriately referred to as the ACK/NACK logic and performs a similar function to that of the valid message logic 40, but for the ACK/NACK bus 12. The logic 42 decodes the ACK/NACK bus 12 when the storage control unit 20 is expecting a response to a message which it generates and it creates the proper code for the storage control unit 20 in its response to messages which it receives off of the system bus 10.
Within the details of the storage control unit 20, there is also illustrated the command buffer 44 which is actually comprised of a plurality of buffers. The command buffer 44 holds the address and source ID of the read message which the storage control unit 20 is currently servicing. In this regard, there are several lines coupling into and out of the command buffer 44. A 32 bit address line 45 intercouples between the transceivers 38 and the command buffer 44. The transceivers 38 may be comprised of registers operating in combination with multiplexers for communicating address and fetch data with the system bus.
Also, there is a 5 bit source ID line 46 similarly coupling. There is a "clear" line 47 and there is a 32 bit address line 48. Two control lines couple from the command buffer 44. These are the read buffer full signal on line 49 and the write buffer full signal on line 50. The read buffer full signal and the write buffer full signal indicate that the storage control unit is servicing a read or a write message, respectively. The signal on lines 49 and 50 is coupled to the command arbitration logic 52.
In the details of the storage control unit 20, the results are provided to OPCODE control. This includes the OPCODE decode block 56. This logic block decodes the OPCODE field of the system bus messages into valid read and write commands. As noted in the detailed drawing, there is a 6 bit input to the OPCODE decode block 56 and there are at lines 57 and 58 corresponding write and read signal lines.
There is also provided the OPCODE select logic 60. This logic encodes the write or read CE signals into their corresponding OPCODE code. The OPCODE select logic 60 receives these signals from the fetch sequencer 70. In this regard, note in the detailed logic the write line 61 and the read CE line 62.
The command arbitration logic 52 arbitrates between the read and write commands directly from the system bus, read and write commands stored in the command buffer 44, which could not be executed immediately when received off the system bus because of some other command being executed by the storage control unit, and refresh requests generated by the refresh sequencer 75.
Also associated with the command arbitration logic 52 is a store sequencer 72. The command arbitration logic 52 provides either a refresh, store, or fetch command to the proper sequencer. This is illustrated in the detail block diagram by the "refresh" line coupling to the refresh sequencer 75, the "store" line coupling to the store sequencer 72 and the "fetch" line coupling to the fetch sequencer 70. In addition, when the read (write) buffer full line is active and a read (write) command is received off of the system bus, the command arbitration logic 52 activates the NACK signal to the ACK/NACK logic 42. This is illustrated in the detailed block diagram by the line 71.
The sequencers 70, 72 and 75 provide the necessary control signals needed to carry out fetch, store and refresh commands, respectively. For example, the fetch sequencer 70 generates control signals to the array control unit 22 for a "fetch" operation, controls the selection of the proper OPCODE, controls multiplexing of messages and data onto the system bus, controls the requesting of the use of the system bus, and clears the read buffer part of the command buffer when it is ready to receive the next read command, among other tasks. This is the aforementioned read clear line 47 coupling from the fetch sequencer 70 to the command buffer 44.
Associated with the fetch sequencer 70 is the request/grant logic 78. The logic 78 provides the interface between the storage control unit 20 and the bus control unit 34. The request/grant logic 78 creates the proper bus request code for write and generic message requests from the fetch sequencer 70, and when a bus grant is received, the logic 78 output enables the system bus transceivers 38 and informs the fetch sequencer 70 to continue sequencing. On the bus control unit side, there is the 4 bit bus request line coupling from the logic 78 to the arbitration logic 36. The single bit bus grant line couples from the logic 36 back to the request/grant logic 78. On the other side of the logic block 78 are the input signals thereto which include the write request signal on line 64 and the generic message request signal on line 65. The output lines from the logic 78 include the grant received signal on line 66 and the enable transceivers signal on line 67. Lines 64 and 65 couple from the fetch sequencer 70. The grant received signal on line 66 couples to the fetch sequencer 70 while the transceiver enable signal on line 67 couples back to the system bus transceivers 38.
The input data coupled by way of the system bus transceivers 38, which is 64 bits of data, couples to the ECC (error correcting code) generator 80. The output of the generator 80 couples to both the interface registers 82 as well as the data/address multiplexer 84. The ECC generator 80 provides a proper ECC (8 bits) code for the 64 bits of data being stored in the memory. The data/address multiplexer 84 multiplexes addresses from the read buffer portion of the command buffer 44 with addresses and data from the system bus 10. This is for the system bus fetch commands which are delayed by the storage control unit because it is busy executing some other command. Also associated with the ECC generator 80 is a parity check box 81.
On the data output end of the system, it is noted that the interface registers 82 couple to the ECC check and correct box 86 which in turn couples by way of the parity generator 88 to the system bus transceivers 38. The ECC check and correct logic checks for ECC errors and corrects them, if possible, when data is being put out onto the system bus by the storage control unit 20.
There has now been described hereinbefore, the basic components comprising the storage control unit 20. Now, consideration is given to a sequence of operation usable in carrying out the concepts of the present invention. During a memory fetch operation, when data has been accessed out of the memory array 29, and is being clocked through the fetch data path, the fetch sequencer 70 causes a write request to be sent to the bus control unit 34 by activating the write request line 64 to the request/grant logic 78. In this regard, the basic fetch data path is from the array 29 by way of registers 31 and 24 to the interface registers 82, and through boxes 86 and 88 to the transceivers 38 and from there to the system bus 10.
If the bus grant signal, from the arbitration logic 36 is received by the storage control unit 20 immediately, the data continues, nonstop, through the rest of the fetch data path and onto the system bus. This data is immediately preceded by a write message with the command buffer address and source ID signals inserted into the address and designation ID fields of the write message. The fetch sequencer 70 activates the multiplex control line 91 that couples up to the transceivers 38, in order to enable the write message with the command buffer address and source ID onto the system bus. The fetch sequencer 70 also deactivates this signal on line 91 for the following eight cycles to enable the fetch data onto the system bus. In this regard note the address and source ID lines intercoupling between the command buffer 44 and the transceivers 38. If, however, the bus grant signal is delayed, because some other device was granted use of the system bus first, then the fetch sequencer loops in a "hold" state, holding the data in the fetch data path until the bus grant signal is received.
When fetch data is being transferred out onto the system bus 10, it is checked for the correct ECC by the ECC check and correct logic 86. If there is no ECC error, then when the last double word is passed onto the system bus 10, the fetch sequencer 70 clears the read buffer full signal in the command buffer 44 by activating the "clear read" signal, namely, line 47 and the command buffer is therefore ready to accept the next read command from the system bus. If, however, a correctable error (CE) occurs while data is being passed onto the system bus 10, the ECC check and correct logic 86 activates the CE line 89 to the fetch sequencer 70 while the data transfer continues. The fetch sequencer 70 does not clear the read buffer full signal at line 49, but rather activates the generic message request line, which is line 65 to the request/grant logic 78. This logic, in turn, encodes the bus request lines with a generic message request to the bus control unit 34. The fetch sequencer 70 also activates the read CE line 62 to the OPCODE select logic 60, and selects the command buffer address and source ID fields to be the address and destination ID fields of the pending read CE message. When the bus grant signal is received, this information is placed onto the system bus. The cache unit which has just received the corrected data from the storage control unit 20 responds to this message by performing a writeback of the corrected data to the memory subsystem. In this way, if the CE was caused by a soft error in memory, then the error is written over with the corrected data. If the cache unit which receives the read CE message is busy servicing some other system bus request, then it will not acknowledge the message. The fetch sequencer 70 will then repeat the process of requesting the bus, receiving the grant, and putting out the read CE message until it receives no NACK signal. Only then is the read buffer full signal cleared and the fetch sequencer is ready to receive another read command from the system bus.
As indicated previously, the read message that is generated from the memory controller has an address field and destination ID corresponding to the stored address field and source identification code. This is the information transferred from the command buffer 44 to the transceivers 38. In accordance with the preferred embodiment of the present invention this is a special type of read message instead of a normal broadcast read message. This is because in accordance with the system bus protocol, shared data comes from the memory subsystem, regardless of whether or not one or more caches has the requested block. In addition, the storage control unit usually only contains a single read buffer location. When this single read buffer location is full, the storage control unit will not acknowledge any other read messages which appear on the system bus that it should be servicing. Therefore, if the block on which the CE occured was marked as shared, and a normal broadcast read message was used to request the writing of the block back to memory, then the storage control unit would end up not acknowledging its own message since it does not clear the read buffer location until the data has been recycled. Even if the storage control unit contained more than one read buffer, this deadlock situation could still occur if all of the read buffers of the storage control unit are full when the CE occurred. If the protocol instead is such that shared data was returned from another cache, if it possessed a copy of the block, then a normal broadcast read could be used to recycle data, as long as it could be guaranteed that the read message would be received by the cache before it would have a chance to replace it with another block. In such an embodiment of the invention then a normal read can be used without requiring source identification.
Having now described a limited number of embodiments of the present invention, it should now be apparent to those skilled in the art that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention as defined by the appended claims.
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A system for correcting soft memory failures such as alpha particle failures in a dynamic random access memory and in a computer system wherein writeback caches are employed in a system bus environment. The address field and source identification code associated with a detected data error are stored. A generic bus request signal is generated and upon a bus grant a read message is issued on the system bus having an address field and destination address code corresponding to the stored address field and source identification code. In response to the read message, the device indicated by the identification code writes back to memory the correct data corresponding to the address field.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fan filter unit to be installed in cleanrooms of factories for manufacturing semiconductor devices, liquid-crystal panels, and films and more particularly, to a fan filter unit comprising a ventilation fan and dust and chemical filters incorporated into an enclosure, which removes efficiently dust and chemical substance existing in the atmosphere of a cleanroom by the chemical and dust filters and which enables energy saving of the fan and reduction of the air circulating space.
2. Description of the Related Art
To maintain the cleanliness of air in the cleanroom at a specific level, typically, cleanroom systems have been used. For example, whole laminar flow type cleanroom systems have been used for this purpose, which comprise fan filter units of this sort arranged on the whole ceiling surface of the cleanroom. FIG. 1 schematically shows the configuration of an example of the prior-art cleanroom systems of this sort.
The prior-art cleanroom system 100 shown in FIG. 1 comprises a cleanroom 140 , a ceiling chamber 147 formed over the cleanroom 140 , fan filter units 142 arranged in a matrix array on the whole ceiling surface 140 a of the cleanroom 140 , an underfloor region 144 defined by floor panels 143 arranged on the floor of the cleanroom 140 , a cooling coil 145 for air-temperature control mounted in the region 144 , and an air circulation path 146 that connects the region 144 with the chamber 147 . Each of the fan filter units 142 includes a ventilation fan 148 and a dust filter 141 . Each of the floor panels 143 has a punched or perforated structure that allows the air to penetrate.
With the prior-art cleanroom system 100 shown in FIG. 1, the air existing in the ceiling chamber 147 is introduced into the inside of the fan filter units 142 by their fans 148 . The air thus introduced is passed through the filters 141 to be cleaned by the same. The air thus cleaned or filtered is emitted or blown to the inside of the cleanroom 140 . At this time, the cleaned air emitted from the units 142 form a vertical laminar flow of air that heads for the floor panel 143 from the ceiling surface 140 a of the cleanroom 140 . The cleaned air thus emitted into the cleanroom 140 flows vertically into the underfloor region 144 through the floor panels 143 and then, returns to the ceiling chamber 147 through the cooling coil 145 and the circulation path 146 . Thereafter, the air thus returned to the chamber 147 is introduced into the cleanroom 140 again.
Through the above-described processes, the clean air is repeatedly circulated in the cleanroom system 100 . The cooling coil 145 serves to decrease the thermal load of the circulating air and therefore, the clean air with a fixed temperature is always supplied to the cleanroom 140 . Also, since the vertical laminar flow of the air is formed in the cleanroom 140 , the inside of the cleanroom 140 can be maintained at a specific high cleanliness level.
The Japanese Non-Examined Patent Publication No. 9-287791 published in November 1997 discloses a cleanroom system having approximately the same configuration as that shown in FIG. 1 .
Although the above-described cleanroom system 100 makes the cleanroom 140 highly clean, there is an anxiety that defects occur in the product due to contamination induced by chemical substance existing in the atmosphere in the leading-edge manufacturing processes for highly miniaturized products such as ultralarge-scale integrated circuits (ULSIs). To cope with the anxiety, fan filter units having chemical filters have been developed and used, an example of which is shown in FIG. 2 .
The prior-art fan filter unit 250 shown in FIG. 2 comprises an enclosure or casing 252 having a first cylindrical part 252 a and a second cylindrical part 252 b that are coaxially connected together. The first part 252 a is smaller in size than the second part 252 b . The bottom end of the first part 252 a is connected to the top end of the second part 252 b . The inner space of the first part 252 a communicates with the inner space of the second part 252 b.
An air inlet 252 c is formed at the top end of the first part 252 a . A ventilation fan 253 is mounted in the first part 252 a . The fan 253 is driven by a motor (not shown) provided in the part 252 a . An air outlet 252 d is formed at the bottom end of the second part 252 b . A dust filter 254 for removing dust or particles and a chemical filter 251 for removing chemical substance are mounted to be vertically apart from each other in the second part 252 b . The dust filter 254 is fixed to the bottom end of the second part 252 b so as to close the air outlet 252 d . The chemical filter 251 is fixed to the inner wall of the second part 252 b over the dust filter 254 at a specific distance. A partition plate 255 having holes 255 a in its peripheral area is fixed to the inner wall of the second part 252 b over the chemical filter 251 at a specific distance. The plate 255 divides the inner space of the enclosure 252 into upper and lower ones. The upper and lower spaces thus divided are connected to each other through the holes 255 a of the plate 255 .
With the prior-art fan filter unit 250 shown in FIG. 2, the outside air 261 existing in the outside of the unit 250 is introduced into the enclosure 252 through the air inlet 252 c , forming the air 262 . The air 262 thus introduced into the enclosure 252 flows to reach the chemical filter 251 through the holes 255 a of the partition plate 255 . The chemical filter 251 removes chemical substances contained in the air 262 , forming the chemical-removed air 263 . The air 263 thus filtered further flows to the dust filter 254 and penetrates the same. The dust filter 254 removes dust or particles contained in the air 263 . As a result, the purified air 264 is emitted from the outlet 252 d of the enclosure 252 to the outside of the unit 250 .
The prior-art unit 250 shown in FIG. 2 can be used as the fan filter unit 142 of the prior-art cleanroom system 100 shown in FIG. 1 . In this case, the concentration of chemical substance existing in the atmosphere of the cleanroom 140 can be lowered, because the unit 250 includes the chemical filter 251 . To further decrease the concentration of chemical substance in the cleanroom 140 , there is the need to increase the flow rate of the purified air 264 emitted from the unit 250 , thereby raising the flow rate of the air 262 that penetrates the chemical filter 251 .
However, if the flow rate of the purified air 264 emitted from the unit 250 is increased, the overall amount of the circulating air within the cleanroom system 140 increases. This raises a problem that the air circulating space (i.e., the air circulation path 146 and the ceiling chamber 147 ) needs to be expanded.
Also, to allow the increased circulating air to penetrate the path 146 and the air-cooling coil 145 , the fan 253 needs to provide higher static pressure. Thus, there is a problem that electric power consumption of the motor for driving the fan 253 is raised.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a fan filter unit that decreases efficiently the concentration of chemical substance existing in the atmosphere while the expansion of the air circulating space and the electric power consumption increase of the fan-driving motor are suppressed.
The above object together with others not specifically mentioned will become clear to those skilled in the art from the following description.
A fan filter unit according to the present invention comprises:
an enclosure having an air inlet through which an outside air is introduced into the enclosure and an air outlet through which a cleaned air is emitted or discharged from the enclosure;
a chemical filter mounted in the enclosure to remove chemical substance existing in the outside air;
a dust filter mounted in the enclosure to remove dust existing in the outside air;
a fan mounted in the enclosure to introduce the outside air into the enclosure through the air inlet and to emit the cleaned air to outside of the enclosure; and
a bypassing path for returning part of the outside air that has penetrated the chemical filter to an upstream side of the fan without penetrating the dust filter.
With the fan filter unit according to the present invention, the bypassing path is provided for returning part of the outside air that has penetrated the chemical filter to an upstream side of the fan without penetrating the dust filter (i.e., without passing through the air circulating space and the air cooling coil). Thus, the necessary pressure loss occurring in the circulation of the outside air through the dust filter and other necessary members such as floor panels, a cooling coil, and an air circulating space can be reduced. As a result, the electric power consumption increase of the fan-driving motor can be suppressed.
Moreover, since the amount of the air penetrating the chemical filter is increased without increasing the overall amount of the air that is circulated in the cleanroom, the concentration of chemical substance existing in the atmosphere of the cleanroom can be decreased while the expansion of the air circulating space can be suppressed.
In a preferred embodiment of the unit according to the invention, a damper is further provided in the bypassing path for adjusting the amount of the outside air returned to the upstream side of the fan. In this case, it is preferred that the dumper is adjusted in such a way that the velocity of the air at the air outlet of the enclosure is set at a specific value.
In another preferred embodiment of the unit according to the invention, a sensor or detector is further provided for sensing or detecting the concentration of chemical substance existing in the air, in which the damper is controlled on the basis of the result of sensing or detection. In this case, it is preferred that the sensor or detector is used to sense or detect the concentration of chemical substance existing in the air in a cleanroom itself or in an air circulating space of a cleanroom.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the present invention may be readily carried into effect, it will now be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view showing the configuration of a prior-art cleanroom system equipped with fan filter units on its ceiling.
FIG. 2 is a schematic cross-sectional view showing the structure of a prior-art fan filter unit into which a chemical filter and a dust filter are incorporated.
FIG. 3 is a schematic plan view showing the configuration of a fan filter unit according to a first embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view along the line IV—IV in FIG. 3 .
FIG. 5 is a schematic cross-sectional view showing the configuration of a cleanroom system equipped with the fan filter units according to the first embodiment of the invention on its ceiling.
FIG. 6 is a schematic cross-sectional view showing the configuration of a fan filter unit according to a second embodiment of the invention, which is along the line IV—IV in FIG. 3 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will be described in detail below while referring to the drawings attached.
First Embodiment
A fan filter unit according to a first embodiment of the invention is shown in FIGS. 3 and 4.
As shown in FIGS. 3 and 4, a fan filter unit 10 according to the first embodiment is comprised of an enclosure or casing 13 with an approximately rectangular plan shape. The enclosure 13 is formed by a cylindrical inner member 11 and a cylindrical outer member 12 .
The inner cylindrical member 11 of the enclosure 13 includes a first cylindrical part 11 a and a second cylindrical part 11 b , both of which are extending vertically. The first and second parts 11 a and 11 b are fixed together to be coaxial with respect to a common vertical axis by way of plate-shaped third and fourth parts 11 c and 11 d . The third and fourth parts 11 c and 11 d extend laterally. The first part 11 a is entirely located inside the second part 11 b . The third part 11 c is located over the fourth part 11 d at a specific distance. The top end of the first part 11 a is connected to the top end of the second part 11 b by way of the third part 11 c . The bottom end of the first part 11 a is connected to the bottom end of the second part 11 b by way of the fourth part 11 d.
The outer cylindrical member 12 of the enclosure 13 includes a first cylindrical part 12 a and a second cylindrical part 12 b , both of which are extending vertically. The first and second parts 12 a and 12 b are fixed together to be coaxial with respect to the common vertical axis for the inner member 11 by way of a plate-shaped third part 12 c . The third part 12 c extends laterally. The first part 12 a is entirely located inside the second part 12 b . The top end of the first part 12 a is connected to the top end of the second part 12 b by way of the third part 12 c . The bottom end of the first part 12 a is not connected to the bottom end of the second part 12 b.
As clearly shown in FIG. 3, the second part 11 a of the inner member 11 and the second part 12 b of the outer member 12 are connected to each other with four supporting members 15 extending along the lateral, longitudinal axis of the enclosure 13 . Thus, the inner member 11 is fixed to the outer member 12 at a specific gap.
An air-returning path 2 is formed between the outer surfaces of the second and third parts 11 b and 11 c of the inner member 11 and the inner surfaces of the first, second, and third parts 12 a , 12 b , and 12 c of the outer member 12 . The path 2 extends along the whole outer surface of the inner member 11 .
A rectangular air inlet 11 e is formed at the top end of the first part 11 a of the inner member 11 . The inlet 11 e is defined by the top edge of the first part 11 a . The first part 12 a of the outer member 12 is entirely overlapped with the inlet 11 e . The third part 12 c of the outer member 12 is partially overlapped with the inlet 11 e . Thus, only inner part of the inlet 11 e is exposed to the outside of the enclosure 13 and the remaining part of the inlet 11 e is exposed to the air path 2 .
A ventilation fan 3 is mounted horizontally in the first part 11 a of the inner member 11 , as shown in FIGS. 3 and 4. The fan 3 is driven by a motor (not shown) mounted in the first part 11 a . The inner part of the fan 3 is exposed to the outside of the unit 10 and the outer part thereof is exposed to the air path 2 .
A chemical filter 1 is located in the second part 11 b of the inner member 11 . The filter 1 is fixed to the bottom end of the second part 11 b so as to close the bottom opening 11 f of the part 11 b.
The chemical filter 1 may be made of a material such as activated carbon, activated carbon mixed with a specific chemical agent, or ion-exchange fibers, which removes alkaline gases, acid gases, or organic gases.
A partition plate 14 is fixed to the inner wall of the second part 11 b of the inner member 11 . The plate 14 is located just over the chemical filter 1 at a specific distance. The plate 14 , which has penetrating holes 14 a in its peripheral area, divides the inner space of the member 11 into upper and lower ones. The upper and lower spaces thus divided are connected together by way of the holes 14 a.
A rectangular air outlet 12 d is formed at the bottom end of the second part 12 b of the outer member 12 . The outlet 11 d is defined by the bottom edge of the second part 12 b . The outlet 11 d is larger than the bottom opening 11 f of the second part 11 b of the inner member 11 and the chemical filter 1 .
A dust filter 4 is located in the second part 12 b of the outer member 12 . The filter 4 is fixed to the bottom end of the second part 12 b so as to close the outlet 12 d . The filter 4 is apart vertically from the chemical filter 3 .
As the dust filter 4 , for example, a HEPA (High Efficiency Particulate Air) filter or an ULPA (Ultra Low Penetration Air) filter may be used.
Next, the operation of the fan filter unit 10 having the above-described configuration is explained below.
First, the outside air 16 existing outside the filter fan unit 10 is introduced into the inner member 11 of the enclosure 13 by way of the inner, exposed part of the air inlet 11 e due to the action of the fan 3 , forming the inside air 17 . The inside air 17 thus formed in the member 11 is sent to the underlying chemical filter 1 due to the action of the fan 3 by way of the holes 14 a of the partition plate 14 and then, it penetrates the filter 1 . Thus, specific chemical substance is removed from the air 17 by the filter 1 , forming the chemically filtered air 18 .
Part of the chemically filtered air 18 from which specific chemical substance has been removed flows to the dust filter 4 to penetrate the same toward the outside of the unit 10 . Dust existing in the air 18 is removed by the dust filter 4 , forming the cleaned or purified air 19 outside the unit 10 . The air 19 is emitted from the air outlet 12 d of the unit 10 .
On the other hand, the remainder of the chemically filtered air 18 is returned to the air inlet 11 e by way of the air-returning path 2 formed between the inner and outer members 11 and 12 . In other words, the path 2 serves as a bypassing path for returning the remaining part of the air 18 to the inlet 11 e without penetrating the dust filter 4 and emitting to the outside. The air 18 thus returned to the inlet 11 e is introduced again into the first part 11 a of the inner member 11 . The chemically filtered air 18 thus returned and the outside air 16 thus newly introduced are mixed together to form the inside air 17 , which passes through the chemical filter 1 .
Thus, the chemically filtered air 18 that has passed through the chemical filter 1 is repeatedly circulated in the fan filter unit 10 . As a result, the chemical substance contained in the outside air 17 can be removed efficiently without increasing the flow rate of the cleaned or purified air 19 emitted from the unit 10 .
Next, a cleanroom system equipped with the fan filter units 10 is explained below with reference to FIG. 5 .
A cleanroom system 29 shown in FIG. 5 comprises a cleanroom 20 , a ceiling chamber 25 formed over the cleanroom 20 , the fan filter units 10 arranged on the whole ceiling surface 20 a of the cleanroom 20 in a matrix array, an underfloor region 22 defined by floor panels 21 arranged on the floor of the cleanroom 20 , a cooling coil 23 for air-temperature control mounted in the region 22 , and an air-circulation path 24 that connects the underfloor region 22 with the ceiling chamber 25 . Each of the fan filter units 10 has the configuration according to the first embodiment as described above. The floor panel 21 has a punched or perforated structure that allows the air to penetrate.
With the cleanroom system 29 shown in FIG. 5, the air existing in the ceiling chamber 25 is introduced into the inside of the fan filter units 10 due to the sucking action of the fans 3 . The air thus introduced is cleaned or purified by penetrating the chemical filters 1 and the dust filters 4 of the units 10 . The air thus cleaned or purified is then emitted to the inside of the cleanroom 20 . At this time, the cleaned air emitted from the units 10 form a vertical laminar flow of air that heads for the floor panel 21 from the ceiling surface 20 a of the cleanroom 20 . The cleaned air in the cleanroom 20 flows into the underfloor region 22 through the floor panels 21 and then, returns to the ceiling chamber 25 by way of the cooling coil 23 and the circulation path 24 . Thereafter, the air existing in the chamber 25 is introduced into the cleanroom 20 again.
Through the above-described processes, the clean air is circulated in the cleanroom system 29 as shown by arrows in FIG. 5 . The cooling coil 23 serves to decrease the thermal load of the circulating air and therefore, the clean air with a fixed temperature is supplied to the cleanroom 20 .
The fan filter units 10 remove efficiently desired chemical substance from the air and thus, the removing or filtering efficiency of desired chemical substance is raised. This means that the flow rate increase of the air emitted from the units 10 is not necessary. Accordingly, the air-circulation path 24 and the ceiling chamber 25 (i.e., the air circulating space) need not to be expanded for raising the efficiency of removing the chemical substance.
Subsequently, to compare the cleanroom system 29 including the fan filter units 10 according to the first embodiment of the invention with the prior-art cleanroom system 100 using the prior-art fan filter units 250 , the inventor calculated the pressure drop of air.
In this calculation, 50% of the chemically filtered air 18 was set to be returned to the inlet side of the unit 10 without passing through the dust filter 4 . The pressure losses L 1 , L 2 , and L 3 of the chemical filter 1 , the path 2 , and the dust filter 4 for the air were set at 3 mmAq, 1 mmAq, and 10 mmAq, respectively. The pressure losses L 4 , L 5 , and L 6 of the floor panels 21 , the cooling coil 23 , and the returning path 24 for the air were set at 2 mmAq, 3 mmAq, and 2 mmAq, respectively.
When the prior-art fan filter units 50 were used, the total pressure loss L of the air of the cleanroom system 100 is given as the sum of the pressure losses of the chemical filter 251 , the dust filter 254 , the floor panels 143 , the cooling coil 145 , and the path 146 . Thus, the following equation (1) is established.
L=L 1 + L 3 + L 4 + L 5 + L 6 (1)
As a result, total pressure loss L of the cleanroom system 100 with the units 50 is equal to 20 mmAq (i.e., L=20 mmAq).
On the other hand, when the fan filter units 10 according to the first embodiment of the invention were used, 50% of the air 18 is returned to the inlet side of the unit 10 without passing through the dust filter 4 . Accordingly, the total pressure loss L of the air of the cleanroom system 100 is given as the average of the sum of the pressure losses of the chemical filter 1 and the path 2 and the sum of the pressure losses of the chemical filter 1 , the dust filter 4 , the floor panels 21 , the cooling coil 23 , and the path 24 . Thus, the following equation (2) is established. L = ( L1 + L2 ) + ( L1 + L3 + L4 + L5 + L6 ) 2 ( 2 )
As a result, total pressure loss L of the cleanroom system 100 with the units 10 is equal to 12 mmAq (i.e., L=12 mmAq), which is (⅗) times the value with the prior-art units 50 .
As explained above, with the cleanroom system 29 using the fan filter units 10 according to the first embodiment, the total pressure loss L is lowered and as a result, the electric power consumption of the motors driving the fans 3 can be decreased.
Also, as already explained above, the unit 10 has the bypass path 12 between the inner and outer members 11 and 12 of the enclosure 13 while the dust filter 4 is located in the outer member 12 . Part of the air 18 that has passed through the chemical filter 1 is returned to the inside of the inner member 11 by way of the path 12 . Accordingly, the function of the unit 10 to remove the specific chemical substance without increasing the flow rate of the air to be emitted from the unit 10 .
Moreover, with the cleanroom 29 using the units 10 according to the first embodiment, the function of the cleanroom 29 to remove the specific chemical substance can be enhanced without expanding the circulating space of the air. Since the pressure loss of the air in the system 29 is decreased, the electric power consumption of the motors driving the fans 3 is lowered.
Second Embodiment
FIG. 6 shows a fan filter unit 10 A according to a second embodiment of the invention, which has the same configuration as that of the fan filter unit 10 according to the first embodiment, except that dampers 36 are provided in the returning or bypassing path 2 . Thus, the explanation about the same configuration as the unit 10 is omitted here for the sake of simplification by attaching the same reference symbols as used the first embodiment to the same or corresponding elements in FIG. 6 .
The unit 10 A comprises the dampers 36 located in the path 2 near the air inlet 11 e , and damper controllers 37 located onto the outer member 12 of the enclosure 13 for controlling the respective dampers 36 .
Each of the dampers 36 has two fins. The flow rate of the air 18 passing through the path 2 is controlled or adjusted by changing the angel of the fins with respect to the flowing direction of the air 18 .
Each of the damper controller 37 is electrically connected to a sensor or detector 30 for sensing or detecting the desired chemical substance. The sensor 30 is located in the cleanroom 20 or the air path 24 . The sensor 30 senses the specific chemical substance existing in the air flowing in the cleanroom 20 or path 24 and then, sends a signal S to the damper controllers 37 according to the sensing result (i.e., the concentration of the chemical substance). In response to the signal S, the controllers 37 adjusted the angle of the fins of the dampers 36 .
For example, when the concentration of the specific chemical substance is higher than a predetermined reference value, the controllers 37 controls the corresponding dampers 36 to widen their paths for the air 18 . Thus, the flow rate of the air 18 to be returned to the upstream side (i.e., the air inlet 11 e ) is increased and thus, the removing or filtering efficiency of the chemical substance is improved. As a result, the concentration of the chemical substance existing in the cleanroom 20 or the circulating path 24 is kept at the specific level or lower.
As the sensor 30 , any ion chromatograph may be used for sensing the ammonia concentration and any gas chromatograph mass spectrometer may be used for sensing the organic substance concentration.
As explained above, with the fan filter unit 10 A according to the second embodiment of FIG. 6, the dampers 36 are additionally provided in the bypassing path 2 to control the flow rate of the air 18 on the basis of the concentration of the chemical substance sensed by the sensor 30 , thereby controlling the flow rate of the air 18 in the path 2 . Thus, the removing or eliminating efficiency of the chemical substance or substances can be further raised compared with the unit 10 according to the first embodiment. This facilitates keeping the chemical substance or substances at or lower than the specific value.
VARIATIONS
In the above-described fan filter units 10 and 10 A according to the first and second embodiments, the bypassing path 2 is formed to extend over the whole outer surface of the second part 11 b of the inner member 11 . However, the path 2 may be located only on the opposing outer surfaces of the second part 11 b of the inner member 11 , in other words, the cross-section of the path 2 may be determined so that the air flows through the path 2 at a desired flow rate.
In the unit 10 A according to the second embodiment, the dumpers 36 are controlled on the basis of the concentration of the chemical substance detected by the sensor 30 . However, any means for measuring the air flow velocity may be provided in the vicinity of the outlet 12 d in order to measure the flow velocity of the air 19 emitted from the outlet 12 d . In this case, the dampers 36 are controlled in such a way that the flow velocity of the air 19 emitted from the outlet 12 d is kept at a desired value or values.
Needless to say, the invention is not limited to the first and second embodiments. For example, the invention is applicable to a fan module unit comprising a plurality of fan filter units and a common ventilating fan, which are incorporated into an enclosure. In this case, the same advantage as those in the first or second embodiment are given.
While the preferred forms of the present invention have been described, it is to be understood that modifications will be apparent to those skilled in the art without departing from the spirit of the invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
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A fan filter unit for use in cleanrooms is provided, which decreases efficiently the concentration of chemical substance existing in the atmosphere while the expansion of the air circulating space and the electric power consumption increase of the fan-driving motor are suppressed. The unit comprises an enclosure having an air inlet through which an outside air is introduced into the enclosure and an air outlet through which a cleaned air is emitted or discharged from the enclosure; a chemical filter mounted in the enclosure to remove chemical substance existing in the outside air; a dust filter mounted in the enclosure to remove dust existing in the outside air; a fan mounted in the enclosure to introduce the outside air into the enclosure through the air inlet and to emit the cleaned air to outside of the enclosure; and a bypassing path for returning part of the outside air that has penetrated the chemical filter to an upstream side of the fan without penetrating the dust filter. A damper may be additionally provided in the bypassing path for adjusting the amount of the outside air returned to the upstream side of the fan. Preferably, the damper is adjusted in such a way that the velocity of the air at the air outlet of the enclosure is set at a specific value.
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This is a continuation application of U.S. Ser. No. 09/707,113, filed Nov. 6, 2000 which is now U.S. Pat. No. 6,490,905.
BACKGROUND OF THE INVENTION
This invention relates to methods and apparatus for installing threaded inserts into a substrate. Such substrates, for example, include films, sheets or plates that may be curved or flat. The substrates may be made of materials such as metal, wood, glass, ceramic, cellulose, leather or plastic and may be completely solid, or partly porous, e.g. in the form of textiles or foam. More particularly, the invention concerns an insert that has a hollow shaft having first and second end portions and an intermediate portion between the end portions and a flange surrounding the first end portion. The insert is installed by passing the intermediate portion and second end portion through a hole in the substrate to preferably, but not essentially, pass through a rear surface of the substrate so that the flange of the insert contacts a front surface of the substrate. The second end portion is then pulled toward the first end portion to collapse the intermediate portion of the shaft upon the rear surface of the substrate (or upon the sidewalls defining the hole in the substrate) to form a gripping structure that secures the insert.
Inserts, as described above, are well known. They are for example readily purchased at local hardware stores for insertion into drywall substrates. Such inserts have more recently been used in production processes to provide threaded structures in substrates that may not be strong enough by themselves to support reliable threads or to reduce production time by eliminating the need to thread individual holes in the substrates with taps.
The use in production has, however, been hampered by the lack of processes and equipment to rapidly and reliably install such inserts.
The first, and still most common, way to install such inserts is by placing the shaft through a hole in the substrate, as above described, and turning a threaded rod with an end flange, e.g. a bolt having a bolt head or flanged threaded mandrel or screw head, into the threads in the second end of the insert thus pulling the second end toward the first end of the insert to collapse the intermediate portion of the insert, as previously described.
Such a method of installation has numerous disadvantages. For example, when the threaded rod with its end flange is turned to collapse the intermediate portion, significant torque is required. The high torque tends to turn the entire insert which can result in a bad installation by causing the formation of a defective gripping structure, or destroying or damaging the substrate or even more commonly, causing failure of threads within the insert. Great care must therefore be taken to assure that the insert does not spin. This often requires that a separate insert retaining means be employed that can withstand the required high torque. Even in such cases, the failure to obtain a good installation is more frequent than can be tolerated by many, if not most, production systems.
More recently, such inserts have been installed in production systems by threading a mandrel into the insert and longitudinally pulling the second end of the shaft of the insert toward the first end of the shaft of the insert, without applying a rotational torque. Nevertheless, the apparatus and processes for accomplishing that result have not been as reliable as desired. In particular, in existing apparatus, when the mandrel was pulled, it was necessary to move the entire drive assembly with the mandrel thus preventing secure attachment of the drive to a cylinder housing for the piston providing the pulling force. As a result, the drive (motor) tended to at least partially move rotationally when it was activated creating wear and misalignment and preventing smooth rotational operation. Further when the drive was activated to rotate the drive shaft, due to wear, as previously described, unacceptably high friction resulted between the drive shaft and piston through which the shaft passed, wearing both the drive shaft and the race or bore through the piston accommodating the drive shaft. As a further result, the turning of the drive shaft tended to also rotate the piston creating wear in the piston seals. The same increase in friction caused an increase in torque requirements to overcome friction losses. All of these problems resulted in significant down time and potentially unsatisfactory installation of the insert. As an even further disadvantage of such apparatus and methods, there was no good way to detect when the screw head (e.g. threaded mandrel) was withdrawn to permit positioning of an insert for loading onto the screw head. There was also no good way to detect where the screw head was screwed into the insert so that the nose retainer contacted the flange of the insert or where the shaft of the insert was inserted into the substrate so that the insert flange contacted the first surface of the substrate or where the screw head had been completely unscrewed from the insert. Accurate use of detectors would have been hampered in such devices due to motion of the drive relative to the cylinder housing and also due to lack of a secure attachment of the drive, the tendency of the piston to rotate and undesirable wear, as previously described. Attempts to stop the piston from rotating themselves give a further wear point as the misalignments due to the insecurely attached drive permit rotational forces to be applied to the piston to be at least partly successful in causing piston rotation due to wear as previously described. The devices further did not lend themselves to safe placement of detectors, i.e. there was no good way for internal detecting mechanisms and the required undesirable movements previously described caused vibration of any sensors used.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of an apparatus in accordance with a preferred embodiment of the present invention where the insert gun of the invention is mounted on a frame.
FIG. 2 is a side view of a preferred embodiment of an insert gun of the present invention.
FIG. 3 is a cross sectional view of the gun of FIG. 2 taken on line 3 — 3 of FIG. 2 .
FIG. 4 is an exploded isometric view of the gun of FIG. 3 .
BRIEF DESCRIPTION OF THE INVENTION
In accordance with the invention there is therefore provided a method and apparatus that overcome or minimize the disadvantages of the methods and apparatus discussed above in the Background of the Invention. Particularly, the apparatus and method of the invention permit reduced apparatus wear, better and more reproducible results, verification of crimp force to collapse the insert to form the grip, confirmation of the collapsed dimension of the insert, and the verification of the presence of proper threads in the installed insert.
As already discussed, the insert to be used in accordance with the invention is a hollow threaded insert for placement into a hole in a substrate where the substrate preferably, but not essentially, has front and rear surfaces. The insert has a shaft with a first end portion, a second end portion and an intermediate portion between the first end portion and second end portion. The insert has a front flange at the first end portion of the shaft for engaging the first (front) surface of the substrate around the hole. The second end portion of the shaft has an internal thread. The intermediate portion includes a gripping means that engages the rear surface of the substrate; or in the case where the shaft of the insert does not pass through the hole, the side walls of the hole; when a force is applied that pulls the second end portion toward the first end portion.
In particular, the method includes the steps of:
activating a rotatable drive having an attached drive shaft in turn having an attached externally threaded mandrel so that the threaded portion of the mandrel rotates into the hollow threaded portion of the insert through the flange until a nose retainer, through which the mandrel passes, contacts the flange of the insert;
moving the drive, drive shaft, mandrel and attached insert to place the shaft of the insert into the hole in the substrate so that the flange of the insert contacts the first surface of the substrate;
pulling the second end portion of the shaft of the insert toward the first end portion of the shaft of the insert by means of a pressure applied to a piston within a cylinder where the piston is connected to the drive shaft holding the mandrel so that the motion of the mandrel collapses the intermediate portion of the insert to grip the second (rear surface of the substrate, or the sidewalls of the hole), and so that the drive shaft moves in a compliant coupling toward the drive;
turning the drive in a reverse direction to disengage the mandrel from the threads in the insert; and
moving the mandrel, nose retainer, drive shaft and drive in a direction away from the flange of the installed insert.
The apparatus for installing a hollow threaded insert through a hole in a substrate includes a piston, a drive shaft, a cylinder, an externally threaded mandrel having threads that match the internal threads of the insert, a compliant coupling, a rotatable drive, and a nose retainer.
Structure is provided for moving the piston, drive shaft, cylinder, mandrel, compliant coupling, rotatable drive and nose retainer toward the flange of the insert so that the threads of the mandrel contact the threads of the insert and for moving the threads of the mandrel into the hollow portion of the insert through the flange so that the threads of the mandrel rotate into the threads within the hollow portion of the insert until the flange of the insert contacts the nose retainer. The structure for moving and rotating includes the drive shaft connected to the mandrel where the drive shaft is set into the compliant coupling to the rotatable drive.
Apparatus is provided for moving the mandrel with attached insert to place the insert shaft into a hole in the substrate so that the flange of the insert contacts the first (front) surface of the substrate and for pulling the second end portion of the insert toward the second (rear surface or hole sidewalls) surface of the substrate by applying pressure to the piston within the cylinder where the piston is connected to the drive shaft so that the intermediate portion of the insert collapses to grip the second) surface of the substrate and so that the drive shaft moves in the coupling toward the drive without moving the drive.
The drive is any suitable rotating drive, e.g. an electric or air motor that can be run in a reverse direction to disengage the screw head from the threads in the insert. Structure is also provided for moving the piston, drive shaft, cylinder, mandrel, slide coupling, rotatable drive and nose retainer away from the flange of the installed insert.
DETAILED DESCRIPTION OF THE INVENTION
The inserts for use in accordance with the present invention are as previously described. Such inserts are usually made from a metallic material, e.g. aluminum, steel, copper, or bronze, but may be made from certain plastics that are both flexible and rigid enough to form a permanent grip when the second end of the insert is drawn toward the second surface of the substrate, and strong enough to maintain threads that can withstand the torque and retaining ability required for a particular application. The first end of the insert frequently has a length about equal to the thickness of the substrate or slightly less. The intermediate portion of the insert shaft, that forms the grip, usually begins at about the rear surface of the substrate and extends to the threads at the second end when the shaft of the insert passes through the substrate.
As already discussed, the substrate may be made of many types of materials and is usually of a thickness of from about 0.5 nm to about 15 cm. The thickness of the substrate is most commonly from about 1 mm to about 10 mm. It is nevertheless to be understood that the invention is not necessarily limited by substrate thickness.
The rotatable drive is usually a hydraulically operated motor, e.g. a pneumatic air motor, but may be any suitable source for application of a rotational force, e.g. an electric motor.
The drive shaft is usually a steel rod that may be provided with bosses or shoulders for seals or retention. A first end of the drive shaft is adapted to be fitted to a variable coupling, as described infra, and the second end of the drive shaft is usually formed to accept a threaded mandrel so that the mandrel, which is a wear part, can be quickly replaced without disassembly of the apparatus of the invention to remove the drive shaft.
An important aspect of the present invention is the variable (or compliant) coupling that permits the first end of the drive shaft to be connected to the spindle of the drive while at the same time allowing the drive shaft to move toward and away from the drive without causing drive movement. Such a coupling also allows for at least some misalignment of the spindle and drive shaft without creating significant wear. Examples of such variable or compliant couplings are slide couplings and spring loaded couplings.
The apparatus for pulling the second end of the shaft of the insert includes a piston within a cylinder. The piston is biased toward the nose of the insert gun, e.g. with a spring. When the piston is forced in a direction away from the insert, e.g. by application of pressurized hydraulic fluid to the face of the piston sealed within a cylinder, the piston engages the drive shaft, that passes through the piston, and forces the drive shaft away from the insert thus pulling the second end of the insert shaft toward the rear surface of the substrate to cause the intermediate portion of the shaft to form a grip against the rear surface of the substrate. “Hydraulic”, as used herein means the use of pressurized fluid to move a piston. The fluid may be either a liquid, e.g. an oil or a gas, e.g. air.
The entire gun assembly, i.e. cylinder, piston, drive, drive shaft, mandrel, variable coupling, and nose retainer, is moved in a slide on a frame using hydraulic, e.g. pneumatic, cylinders connected between the frame and a bracket holding the gun.
The invention may be better understood by reference to the drawings that show a preferred embodiment of the invention.
As seen in FIG. 1, insert gun 10 is mounted on bracket 12 that operates within a slide 14 on a frame 16 . In operation inserts 18 are forced through a blow tube 20 to an oriented position in an insert gripper 22 . The gripper 22 is then moved to a position beneath nose 24 by hydraulic cylinder 26 having its piston 28 interconnected to gripper 22 , so that the mandrel can be lowered to engage the threads of an insert 18 . The lowering of gun 10 is accomplished by hydraulic cylinder 30 connected between bracket 12 and frame 16 .
The gun 10 , whose component parts are best seen in FIGS. 3 and 4, includes a screw head (mandrel) 32 adapted to screw into the threaded second end 34 of the shaft 36 of the insert 18 . Insert 18 further has a first end 38 surrounded by a flange 40 and has intermediate collapsible portion 42 .
Mandrel 32 is readily replaceable and is held by chuck 44 attached to drive shaft 46 . Drive shaft 46 is in turn connected to slide coupling 48 that is connected to drive spindle 50 . Mandrel 32 is stabilized by nose 52 which also acts as a retainer against insert flange 40 when second end 34 is being pulled toward flange 40 .
Gun 10 is further provided with a cylinder 54 and a piston 56 contained within the cylinder 54 . Cylinder 54 includes spring retainer sleeve 58 for holding a spring 60 that biases piston 56 toward a cylinder front end cap 62 . Piston 56 is provided with a through bore 64 permitting passage of shaft 46 . Shaft 46 is free to rotate within bore 64 but is keyed to piston 56 so that longitudinal movement of piston 56 also longitudinally moves shaft 46 . Preferably a thrust bearing 65 is provided to reduce friction with piston 56 when shaft 46 is rotated with respect to piston 56 . This is especially true when a longitudinal force, e.g. the weight of drive 66 , is applied to shaft 46 that increases friction with piston 56 .
A drive 66 is provided that rotates spindle 50 when the drive is activated. Drive 66 is preferably an air motor operated by means of valve 96 controlling flow from air supply 98 but may also be another type of rotating drive such as an electric motor. The drive is securely attached to cylinder 54 by threading the front of drive housing 93 into sleeve 58 . The housing of drive 66 does not move relative to cylinder 54 . The slide coupling 48 permits longitudinal movement of drive shaft 46 relative to spindle 50 so that there is also no longitudinal movement of spindle 50 relative to cylinder 54 even when shaft 46 itself move longitudinally with respect to cylinder 54 .
As previously discussed piston 56 has a central bore 64 , and also has piston front surface 68 facing the screw head 32 . The drive shaft 46 passes through and is retained by central bore 64 so that longitudinal movement of the piston 56 moves drive shaft 46 while permitting drive shaft 46 to rotate within bore 64 .
Cylinder 54 housing piston 56 is rigidly connected to the drive 66 and slidably connected to frame 16 by slide 14 so that cylinder 54 can slide relative to frame 16 but cannot rotate relative frame 16 .
The nose 52 is rigidly connected to cylinder 54 . Nose 52 engages flange 40 of insert 18 to hold it against first surface 68 of substrate 70 when the second end of the insert shaft is pulled toward the first end of the insert shaft to form a grip 72 against second surface 74 of substrate 70 .
A fluid inlet including port 76 in cylinder 54 is provided for permitting fluid under pressure to enter cylinder 54 and contact the front face 68 of piston 56 to push piston 56 and retained drive shaft 46 in a direction toward drive 66 and to cause drive shaft 46 to slide within coupling 48 .
A fluid outlet is also provided to permit fluid to be released from cylinder 54 which may use the same port 76 as the fluid inlet. The direction of flow through port 76 is controlled by an external valve.
A control 78 is provided for controlling the operation of the apparatus in response to input from sensors 80 , 82 , 84 , 86 , and 88 forming part of control 78 . Control 78 activates drive 66 for causing screw head 32 to screw into threaded portion 34 of insert 18 . Control 78 then stops drive 18 and causes cylinder 54 to move in slide 14 relative to frame 16 along with gun 10 and the insert 18 held on the screw head 32 to insert the shaft 36 of the insert into the hole in substrate 70 . The control 78 closes valve 92 permitting outlet from port 76 and causes fluid under pressure from reservoir 94 to enter cylinder 54 through port 76 to force screw head 32 attached to drive shaft 46 by coupling 44 toward drive 66 to cause the grip 72 of the insert 18 to engage second surface 74 of substrate 70 . Control 78 stops fluid inlet into cylinder 54 and opens the outlet to relieve pressure in cylinder 54 . Control 78 then causes drive 66 to activate in reverse to unscrew screw head 32 from now installed insert 18 . Unscrewing from the insert verifies that the threads in the insert are undamaged. Control 78 then causes gun 10 to move relative to the frame in a direction away from the installed insert.
The sensors of the control 78 includes a piston position sensor 80 that may be a magnet moving with the piston and a magnetic field detector attached to the cylinder or may be a feeler switch. Other sensors are: sensor 82 for detecting when cylinder 54 is positioned relative to the frame in a positions where gun 10 (attached to bracket 12 by cylinder 54 ) is withdrawn to permit positioning of an insert for loading onto screw head 32 ; sensor 84 for detecting where the screw head 32 is screwed into the insert so that nose retainer 52 contacts flange 40 of the insert; sensor 88 for detecting where the shaft 18 of the insert is inserted into substrate 70 so that insert flange 40 contacts the first surface 68 of substrate 70 and sensor 86 for detecting where the screw head 32 has been unscrewed from the insert. Control 78 handles signals from the sensors and provides commands to operate pistons, inlet and outlet valve 90 and drive 66 using a programmed logic chip within control 78 .
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A method and apparatus for installing a hollow threaded insert into a hole in a substrate having first and second surfaces. The insert has a hollow shaft having a first end portion, a second end portion and an intermediate portion. The insert has a front flange at the first end portion for engaging the front surface of the substrate around the hole. The second end portion of the shaft has an internal thread and, the intermediate collapses to engage the second surface when a force is applied that pulls the second end portion toward the first end portion.
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RELATIONSHIP TO PRIOR APPLICATIONS
[0001] This non-provisional application claims priority to U.S. Provisional Patent Application Ser. No. 62/139,615 entitled “Funnel Support or Storage System”, filed Mar. 27, 2015, which is herein incorporated by reference in its entirety for all purposes. The present application claims priority to and the benefit of the above application 62/139,615.
FIELD OF THE INVENTION
[0002] The invention is drawn to systems or apparati for supporting and/or storing funnels.
BACKGROUND OF THE INVENTION
[0003] There remains many ways to improve the operational efficiency of servicing motor vehicles, boats, and the like. One problem a motor mechanic frequently encounters when servicing a motor car is locating a relatively clean funnel with which to use to transfer used oil or other vehicle fluids from the engine, transmission, or universal cylinder to a waste receptacle. Frequently the mechanic finds that another mechanic misplaced the correctly-shaped funnel, or that the funnel has been left, still covered in oil or other residue, in a jumble with other different funnels.
[0004] Dowd U.S. Pat. No. 5,381,839 discloses a liquid disburser device including a top member having an upper funnel chamber section for receiving liquid and a lower liquid discharge column leading downwardly from the upper funnel chamber section; the lower discharge column including an inner diameter of sufficiently reduced size whereby liquid enters the discharge column from the upper funnel chamber in a filling equal amount; the discharge column having a plurality of equally angularly spaced tubular members spaced in equal distance about the bottom portion of the discharge column; the tubular members extending downwardly and having respective end portions adapted to be inserted into the inlet of a liquid container for conducting equal amounts of liquid from the funnel chamber into respective containers to be filled therefrom.
[0005] U.S. Patent Application number 20070272714 (Harpenau) discloses a funnel bucket device for storing, transporting and dispensing liquids, comprised of a housing for holding a liquid, having an opening at an upper surface (the opening having the shape of a funnel), a generally concave inclined bottom surface, and having a support system to support the housing. In addition, an online blog (http://i16.photobucket.com/albums/b9/AlbertaBoy/FunnelTree.jpg) discloses a funnel tree apparatus comprising a set of tubes or pipes vertically disposed, each vertical tube or pipe having an upper aperture and connected at its base (lower aperture) to a gently sloping tube of pipe, and wherein the gently sloping tube or pipe comprises a single aperture at one end. In use, the spout of a funnel is placed into the aperture of one of the vertical tubes or pipes and the apparatus is used to drain residual fluids from the funnels into a bucket placed adjacent to the aperture of the gently sloping tube or pipe.
SUMMARY OF THE INVENTION
[0006] The invention contemplates a system or apparatus for supporting, organizing, and storing funnels, the system comprising a first base, a first shaft, wherein the first shaft has a distal end and a proximal end, an external surface and at least one aperture located on the external surface of the first shaft between the distal end and the proximal end, and at least one second shaft, the at least one second shaft having a distal end and a proximal end, wherein the first base is shaped and adapted for receiving the proximal end of the first shaft, and wherein the at least one aperture on the external surface of the first shaft is shaped and adapted for receiving and engaging the proximal end of the at least one second shaft. In one preferred embodiment, the first shaft has a diameter greater than the diameter of the at least one second shaft. In another preferred embodiment, the system comprises a plurality of apertures on the external surface of the first shaft. In a further more preferred embodiment, the system comprises a plurality of second shafts. In one alternative embodiment, at least one second shaft has a diameter smaller than the diameter of one other second shaft. In another alternative embodiment, at least one second shaft has a length smaller than the length of one other second shaft. In another preferred embodiment, the at least one second shaft is shaped and adapted for receiving the neck of a funnel. In one more preferred embodiment, the distal end of the second shaft comprises a spout guide, the spout guide shaped and adapted to receive a spout of a funnel. In a more preferred embodiment, the spout guide is a sphere.
[0007] In another preferred embodiment, the system or apparatus further comprises an open container, the container comprising a second base, and at least one vertical wall. In a more preferred embodiment, the first base is shaped and adapted for placement in the open container. In another more preferred embodiment, the second base of the container is shaped as a circle. In an alternative more preferred embodiment, the second base of the container is shaped as a polygon. In another more preferred embodiment, the container comprises a plurality of vertical walls.
[0008] In another preferred embodiment, the system or apparatus further comprises a handle, wherein the distal end of the first shaft comprises the handle. In a more preferred embodiment, the handle is selected from the group consisting of a circular loop, an oval loop, a hook, and a grip.
[0009] In a more preferred embodiment, the system or apparatus comprises wherein an angle formed by (i) the proximal end of the at least one second shaft engaged in the aperture of the first shaft and by (ii) the first shaft is less than 90°. In another alternative embodiment the angle is less than 60°. In a further alternative embodiment, the angle is less than 30°. In another preferred alternative embodiment an angle formed by (i) the proximal end of one second shaft engaged in an aperture of the first shaft and by (ii) the first shaft is different from an angle formed by (iii) the proximal end of another second shaft engaged in an aperture of the first shaft and by (iv) the first shaft.
[0010] In another embodiment, the funnel tree system or apparatus comprises at least one label, wherein the label is located on the external surface of the first shaft, the label indicating the size of funnel suitable to be placed over the adjacent second shaft. In a more preferred embodiment, the system or apparatus comprises a plurality of labels. In an alternative embodiment, the indication of funnel suitable for placement is etched into the external surface of the first shaft. In another alternative embodiment, the indication is etched onto the surface of the second shaft.
[0011] In a one aspect, the funnel tree system or apparatus is manufactured from oil-resistant materials using at least one process selected from blow molding, die cutting, die pressing, die stamping, extrusion, vacuum infiltration, injection molding, rotational molding, thermoforming, thermoplastic molding and thermosetting. In a second aspect, the oil-resistant materials are paper or organic polymers selected from cellulosics, coated paper, nitrile resins, paper slurry, polybutylene, polyethylene, polyethylene terphthalate, polystyrene, polyvinylchloride thermoplastic resins, and thermosetting resins. In a third aspect, the manufacturing process can include pre-perforation of the apertures on the external surface of the first shaft. In a fourth aspect, the funnel tree system or apparatus is disposable or reusable.
[0012] In another embodiment, the funnel tree may comprise as many or as few second shafts as may be needed by a user. In another embodiment, the funnel tree may be shaped and sized for use in a factory location. In an alternative embodiment, the funnel tree may be shaped and sized for use in a domestic location, for example, a kitchen or the like.
[0013] The invention also provides an ornamental design for a funnel support system, the ornamental design as shown and described.
[0014] In another embodiment, the funnel support system comprises a backing plate, a plurality of second shafts, wherein each second shaft has a proximal end and a distal end, and wherein the second shaft is fixedly attached to the backing plate, wherein the angle formed by the line of the second shaft and the plane of the backing plate is between at least 5° and 85°, and wherein the distal end comprises a spout guide.
[0015] In yet another embodiment, the funnel support system comprises an alternative backing plate, wherein the alternative backing plate comprises two backing plates fixedly attached to each other at about a right angle, a plurality of second shafts, wherein each second shaft has a proximal end and a distal end, and wherein the second shaft is fixedly attached to one of the backing plates, wherein the angle formed by the line of the second shaft and the plane of the backing plate is between at least 5° and 85°, and wherein the distal end comprises a spout guide.
DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1A shows a funnel support system (“Funnel Tree”) 1 as viewed from a side; FIG. 1B shows an illustrative example of how a funnel 7 may be placed on a second shaft (or branch) 3 and spout guide 8 of the system 1 ; and FIGS. 1C, 1D, and 1E show three aerial views of three exemplary tiers of second shafts, showing that they may be placed in a staggered arrangement. FIG. 1A illustrates the funnel tree from a side perspective; FIG. 1 B illustrates a funnel that may be placed over a sprout guide and a part of a second shaft (branch); FIGS. 1C, 1D, and 1E , illustrate a view from above showing the relative positions of the second shafts (branches) of Tier 1 , Tier 2 , and Tier 3 , respectively.
[0017] FIG. 2 shows another funnel support system (“Funnel Rack”) 14 as viewed from the front ( FIG. 2A ) and as viewed from the side ( FIG. 2B ). FIGS. 2A and 2B show an exemplary arrangement and placement of the second shafts 3 having a proximal end attached to the backing plate 17 . Each second shaft 3 further comprises a spout guide 8 at the distal end. Note that for ease of view only a few of the second shafts and spout guides have been shown with reference lines and numbers.
[0018] FIG. 3 shows another funnel support system (“Corner Rack”) 16 as viewed from the front ( FIG. 3A ) and as viewed from above or below ( FIG. 3B ). FIGS. 3A and 3B show an exemplary arrangement and placement of the second shafts 3 having a proximal end attached to an alternative backing plate 17 wherein the alternative backing plate comprises two backing plates 18 fixed to each other at a right angle or thereabouts. Each second shaft 3 further comprises a spout guide 8 at the distal end. Note that for ease of view only a few of the second shafts and spout guides have been shown with reference lines and numbers.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
[0019] Unless defined otherwise, all terms are understood to have the same meaning as commonly used in the art to which they pertain. In this application, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. It is noted that any of the embodiments disclosed herein may be used in various and any combination that can be of benefit. For the purpose of this invention, the following terms are defined below.
[0020] “Oil-resistant” refers to materials for manufacturing a funnel tree system or apparatus, such as natural or organic polymers that are resistant to alcohol, grease, heat and water including but not limited to cellulosics, foams, nitrile resins, paper slurries, thermoplastic resins and thermosetting resins including but not limited to polybutylene, polyethylene, polyethylene terephthalate, and polystyrene; and plastisols (i.e., dispersion grade polyvinylchloride resin in a plasticizer) that are used to form or coat the funnel tree.
[0021] “Operably attached” refers to any means or mechanism by which a second shaft or a base is adhered, connected, glued, sealed, thermoformed, or thermoset to any part of the first shaft, or the first shaft is attached to a base.
[0022] “Operably engaged” refers to any means by which the shaft attaches to, connects with, grips, mates with or snaps onto another shaft or a base.
Description
[0023] The funnel tree tiers' “branches” are angled and arranged for ease of access and storage of multiple funnels of various shapes and sizes. A mechanic may simply slide a funnel “leaf” small end first onto any open tier “branch”. During the storage period, due to the angles of the tiers' “branches”, the funnels residual fluid is allowed to drain from the funnel onto the tier “branch” and then onto the shaft “trunk” then run down to the base “roots” where it remains until it becomes possible and/or necessary to properly dispose of.
[0024] FIG. 1 shows a preferred embodiment of the funnel support system or apparatus 1 from a side perspective. As may be seen on FIG. 1A , the central (first) shaft (or “trunk”) 2 of the funnel tree has a plurality of second shafts (or “branches”) 3 affixed or attached or adhered or otherwise engaged to various locations using a collar 9 on the external surface of the first shaft 2 . The system or apparatus further comprises a handle 4 affixed or attached or adhered or otherwise engaged to the distal end of the central (first) shaft 1 . The system or apparatus further comprises a base 5 , and FIG. 1A also illustrates that the base/first shaft/second shaft/handle unit may be placed in a receptacle, for example, a bucket or catch basin 6 . The catch basin 6 comprises at least one second base 10 and at least one wall 11 . The wall 11 may be vertical relative to the second base 10 and may be perpendicular or may be less than perpendicular relative to the second base 10 . FIG. 1A also shows that an angle 12 may be measured between a branch 3 and the trunk 2 . The angle between the branch and the trunk may be chosen and adapted for use depending upon which size and/or type of funnel is to be placed upon the branch. FIG. 1B shows how a funnel 7 may be placed upon the funnel tree system, wherein the distal end of a second shaft comprises a spout guide 8 . Also shown in FIGS. 1C, 1D, and 1E are aerial views of each of tier 1 , 2 , and 3 , respectively of second shafts, thereby illustrating how the relative placement of each tier of second shafts may be staggered, thereby allowing funnels of different size and shape to be placed upon the branches of the funnel tree system.
[0025] The width of the first shaft can have any dimension suitable for the system or apparatus itself. For example, the width of the first shaft can be 1 mm, it can be 1.5 mm, it can be 2 mm, it can be 2.5 mm, it can be 3 mm, it can be 4 mm, it can be 5 mm, it can be 6 mm, it can be 7 mm, it can be 8 mm, it can 9 mm, it can be 10 mm, it can be 11 mm, it can be 12 mm, it can be 13 mm, it can be 14 mm, it can be 15 mm, it can be 16 mm, it can be 17 mm, it can be 18 mm, it can be 19 mm, it can be 20 mm, it can be 25 mm, it can be 30 mm, or any dimension therebetween. Other larger dimensions are also contemplated and which may be used if the funnel system or apparatus is adapted for use with other proportionally larger systems, apparatus, or tools.
[0026] The width of the second shaft can have any dimension suitable for the system or apparatus itself. For example, the width of the second shaft can be 1 mm, it can be 1.5 mm, it can be 2 mm, it can be 2.5 mm, it can be 3 mm, it can be 4 mm, it can be 5 mm, it can be 6 mm, it can be 7 mm, it can be 8 mm, it can 9 mm, it can be 10 mm, it can be 11 mm, it can be 12 mm, it can be 13 mm, it can be 14 mm, it can be 15 mm, it can be 16 mm, it can be 17 mm, it can be 18 mm, it can be 19 mm, it can be 20 mm, it can be 25 mm, it can be 30 mm, or any dimension therebetween. Other larger dimensions are also contemplated and which may be used if the funnel system or apparatus is adapted for use with other proportionally larger systems, apparatus, or tools.
[0027] The height of the funnel support system can have any dimension suitable for the system or apparatus itself. For example, the height of the first shaft can be 10 cm, it can be 11 cm, it can be 12 cm, it can be 13 cm, it can be 14 cm, it can be 15 cm, it can be 16 cm, it can be 17 cm, it can be 18 cm, it can be 19 cm, it can be 20 cm, it can be 25 cm, it can be 30 cm, it can be 35 cm, it can be 40 cm, it can be 45 cm, it can be 50 cm, it can be 60 cm, it can be 70 cm, it can be 80 cm, it can be 90 cm, it can be 1 m, it can be 1,5 m, or any dimension therebetween. Other larger dimensions are also contemplated and which may be used if the funnel system or apparatus is adapted for use with other proportionally larger systems, apparatus, or tools.
[0028] The width of the funnel support system can have any dimension suitable for the system or apparatus itself. For example, the length of the second shaft can be 5 cm, it can be 6 cm, it can be 7 cm, it can be 8 cm, it can be 9 cm, it can be 10 cm, it can be 11 cm, it can be 12 cm, it can be 13 cm, it can be 14 cm, it can be 15 cm, it can be 16 cm, it can be 17 cm, it can be 18 cm, it can be 19 cm, it can be 20 cm, it can be 25 cm, it can be 30 cm, it can be 35 cm, it can be 40 cm, it can be 45 cm, it can be 50 cm, it can be 60 cm, it can be 70 cm, it can be 80 cm, it can be 90 cm, it can be 1 m, it can be 1,5 m, or any dimension therebetween. Other larger dimensions are also contemplated and which may be used if the funnel system or apparatus is adapted for use with other proportionally larger systems, apparatus, or tools.
[0029] The novelty of the funnel tree disclosed herein may be appreciated by those in the relevant art; the funnel tree component can be manufactured as one piece and without using additional tools to create holes or apertures within the trunk.
[0030] It is also contemplated that the second shaft can be manufactured separately from the first shaft and operably attached to it.
[0031] The invention also contemplates a funnel support system as illustrated in FIGS. 2A and 2B which show the funnel support system (“Funnel Rack”) 13 as viewed from the front ( FIG. 2A ) and as viewed from the side ( FIG. 2B ). The structural elements of the Funnel Rack are essentially identical to those elements as disclosed for the Funnel Tree with the exception that the plurality of second shafts, each comprising a proximal end and a distal end, wherein the proximal end is secured to a backing plate 14 and the distal end comprises a funnel guide 8 . The Funnel Rack may be mounted on a wall or other upright surface and has a similar use to that of the Funnel Tree disclosed above. The advantage of the Funnel Rack is that it may be placed by a user in a convenient location in a workshop and it does not take up the floor space that would otherwise be used by the Funnel Tree. The FIGS. 2A and 2B show an exemplary arrangement and placement of the second shafts 3 having a proximal end attached to a backing plate 14 , also shown is an optional oil or fluid catching basin (or drip bucket) 15 . Each second shaft 3 further comprises a spout guide 8 at the distal end. Note that for ease of view only a few of the second shafts and spout guides have been shown with reference lines and numbers.
[0032] The invention also contemplates a funnel support system as illustrated in FIGS. 3A and 3B which show the funnel support system (“Corner Rack”) 16 as viewed from the front ( FIG. 3A ) and as viewed from above or below ( FIG. 3B ). The structural elements of the Corner Rack are essentially identical to those elements as disclosed for the Funnel Rack with the exception that an alternative backing plate 17 comprises two backing plates 18 fixedly attached to each other perpendicular to each or thereabouts. The Corner Rack may be mounted at the junction of two walls or other upright surfaces and has a similar use to that of the Funnel Rack disclosed above. The advantage of the Corner Rack is that it may be placed by a user in a convenient location in a corner of a workshop that would otherwise not be used and it does not take up the wall space that would otherwise be used by the Funnel Rack. FIGS. 3A and 23B show an exemplary arrangement and placement of the second shafts 3 having a proximal end attached to an alternative backing plate 17 wherein the alternative backing plate comprises two backing plates 18 fixed to each other at a right angle or thereabouts. Each second shaft 3 further comprises a spout guide 8 at the distal end. Note that for ease of view only a few of the second shafts and spout guides have been shown with reference lines and numbers.
[0033] Funnel support systems in various sizes can be color-coded and/or labeled by the manufacturer or at the factory where they are made.
[0034] The funnel support system can be manufactured using a variety of materials. In one embodiment the material can be a metal selected from the group consisting of nickel, nickel-titanium alloy, brass, aluminum, chromel, stainless steel, zinc, copper, gold, platinum, silver, and titanium. In an alternative embodiment the funnel support system comprises a material selected from the group consisting of barium sulfate, titanium oxide, silicone, polyurethane, polyethylene, acrylonitrile butadiene stryrene, polycarbonate, polypropylene, styrene, polyamide, polyimide, PEEK, PEBAX, polyester, polyvinyl chloride (PVC), uPVC, CPVC, ethylene vinyl acetate (EVA), elastomer, polyolefin, fluoropolymers, and co-polymers thereof. In another embodiment, the funnel support system can be manufactured using a combination of a metal and a non-metal material.
[0035] The funnel support system can also comprise a coating, the coating selected from the group consisting of a zinc-aluminum-magnesium coating, a thermal diffusion galvanized coating, a PERMA-GREEN coating, a powder coating, an electrocoating (E-coat or Electrophoretic deposition coating), a paint coating, an epoxy coating, a polyvinyl chloride (PVC) coating, a trivalent chromium coating, a hexavalent chromium coating, a zinc coating, and a copper coating.
[0036] The funnel support system may be manufactured using means know to those of skill in the art. Such means include, but are not limited to die stamping or pressing, vacuum infiltration, injection molding, and the like. In another embodiment, the funnel support system may be manufactured using a three-dimensional (3-D) printer, wherein the dimensions and shape of the funnel support system are entered into a software program, such as the computer-aided design (CAD) software, and the CAD software is used to control the 3-D printing process.
Utility
[0037] Various modifications and variations of the compartmented lid, materials and methods for manufacturing and filling it will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific embodiments, it should be understood that the invention as claimed should not be unduly limited to these specific embodiments. Indeed, various modifications of the described material and methods for carrying out the invention that are known to those persons skilled in the art or related fields are intended to be within the scope of the following claims.
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The invention provides a funnel support system, wherein an exemplary embodiment is a funnel tree system comprising a base, a central trunk, and numerous branches, the branches angled upwards to receive funnels for storage and/or support. In use, the funnel tree may be placed in a bucket to contain residues from the funnels. The funnel support system is of use to those engaged in vehicle and engine mechanics, motorized vehicle repair and service shops, boat repair and service shops, airplane repair and service shops, and the like.
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CROSSREFERENCE TO RELATED APPLICATIONS
This application claims priority from PCT/GB03/01596, having an international filing date of 14 Apr. 2003, and a priority date of 16 Apr. 2002.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
Not Applicable
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC
Not applicable
BACKGROUND OF THE INVENTION
The present invention relates to hydraulically operated downhole tools and in particular, though not exclusively, to a control sub to provide selective control of a hydraulically operated expander tool for tubulars.
It is known in the art to utilise the pressure of fluid pumped through a work string in a well bore to control a hydraulically activated tool in the well bore. For instance, when expanding tubulars such as slotted, screen or solid pipe a rotary expander may be used. These expanders have a cone head with an outer diameter greater than the diameter of the tubular. On the tool are arranged hydraulically operated rollers. When mounted on the end of a work string and inserted into a tubular, hydraulic pressure introduced to the expander tool will force the cone through the tubular and with the aid of the rollers the tubular will be expanded to the diameter of the expander tool.
The hydraulic pressure to operate these tools is typically supplied from the surface of the well bore by pumps. Due to the distances of travel to the location of the expander tool it is difficult to control the operation of the expander tool and, in particular, to provide a constant pressure to give a uniform control and therefore expansion of the tubular in the well bore. It is also difficult to start and/or stop the expander tool at desired locations in the well bore.
It has been recognised that being able to control the flow of hydraulic fluid adjacent a hydraulically operated downhole tool would be advantageous. U.S. Pat. No. 5,392,862 describes a drilling mud flow control sub that provides the necessary fluid flow and pressure to activate an expanding remedial tool such as an underreamer, section mill or other cutting tool. The sub consists of a cylindrical sub assembly housing forming a first upstream end and a second downstream end. The housing is threadably connected between a drill string at its first upstream end and a tool at its downstream end. Intermediate the upstream and downstream ends is located a drop ball seat so that insertion of a drop ball will prevent hydraulic fluid flow to the tool. A rupture disc is affixed to a hole formed in the control sub wall normal to the sub axis, above the drop ball seat, so that when obstructed fluid is shunted from the sub.
This flow control sub provides means to terminate fluid flow to the tools hydraulically operating mechanism while allowing fluid circulation through the sub when the tool is deactivated ‘while tripping’ and/or rotating the drill string. However a major disadvantage of this tool is in the single function operation i.e. in turning the hydraulic mechanism off. There is no selective control of the tool. Additionally when hydraulic fluid is applied to the tool through the sub the pressure of this fluid can only be controlled from the surface as with the prior art systems. Further a disadvantage is in the length of time taken for the drop ball to reach the seat and the associated difficulties if the single ball does not locate correctly in the seat.
It is an object of at least one embodiment of the present invention to provide a control sub for use with a hydraulically operated downhole tool which allows the tool to be operated in selective on and off configurations.
It is a further object of at least one embodiment of the present invention to provide a control sub for use with a hydraulically operated downhole tool which allows control of the hydraulic pressure delivered to the tool.
It is a yet further object of at least one embodiment of the present invention to provide a control sub for use with a hydraulically operated downhole tool which allows selective control of fluid circulation when the tool is run in or tripped from the well.
It is a still further object of the present invention to provide a method of controlling hydraulic pressure to a hydraulically operated downhole tool in a well bore.
BRIEF SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided a control sub for use with a hydraulically operated downhole tool, comprising a tubular assembly having a through passage between an inlet and a first outlet, the inlet being adapted for connection on a workstring, the first outlet being adapted for connection to a hydraulically operated downhole tool, one or more radial outlets extending generally transversely of the tubular assembly, an obturating member moveable between a first position permitting fluid flow through the one or more radial outlets and a second position closing the one or more radial outlets, wherein the obturating member is moved from the first position to the second position by a compressive force applied from the tool.
It will be appreciated that release of the compressive force will open the one or more radial outlets and thus by varying the compressive force applied from the tool the amount of fluid circulated radially out of the sub can be controlled. Preferably the cross-sectional area of the first outlet is greater than the cross-sectional area of the second outlet. By varying the circulation of fluid radially from the sub the fluid exiting the sub through the first outlet can be varied. This fluid exiting the first outlet controls the hydraulic pressure applied to the tool and therefore the operation of the tool.
Preferably the compressive force occurs from the downhole tool remaining static relative to movement of the workstring and the control sub. Thus the control sub acts in a similar manner to weight set tools but provides control as weight is set.
Preferably the tubular assembly comprises an inner sleeve and an outer sleeve, sealingly engaged to each other. Preferably the outer sleeve is adapted to connect to the work string and the inner sleeve is adapted to connect to the tool. More preferably the inner and outer sleeves include mutually engageable faces so that the sleeves may be axially slideable in relation to each other over a fixed distance.
Preferably also the obturating member is a sleeve. Advantageously the sleeve is coupled to the inner sleeve of the tubular assembly. Preferably the obturating member is also axially slideable within the tubular assembly.
Preferably the one or more radial ports are located on the outer sleeve. Advantageously matching radial ports are located on the obturating member such that under compression each set of radial ports align to allow fluid to flow radially from the sub.
Preferably an outer surface of the inner sleeve includes a portion having a polygonal cross-section. Preferably also an inner surface of the outer sleeve has a matching polygonal cross-section. These matching sections ensure that when the work string is rotated the sub is rotated and with it the hydraulically operated tool. More preferably the polygonal cross section is a hex cross-section.
Preferably also the sub includes an indexing mechanism. The indexing mechanism may comprise mutually engageable formations on the inner and outer sleeves. Preferably the engagement formations comprise a member and a recess in which the member may be engaged. The member may comprise a pin and the recess may comprise a slot. Preferably, one of the member and the pin is mounted on the outer sleeve and the other is mounted on the inner sleeve. Typically the slot extends circumferentially around the respective sleeve and the pin may move circumferentially with respect to the slot.
Preferably the slot and/or pin is configured such that the pin and slot move in only one direction to each other when engaged and operated.
Preferably also the slot includes one or more longitudinal profiles as offshoots from the circumferential path. When the pin is located in such a profile, the sleeves may move relative to each other to effect the relocation of the obturating member from one position to another.
According to a second aspect of the present invention there is provided a method of controlling a hydraulically operated downhole tool in a well bore, the method comprising the steps:
(a) mounting above the tool on a work string a control sub, the sub including a first outlet to the tool and one or more radial outlets through which fluid within the work string will flow when not obstructed by an obturating member, the obturating member being moveable under a compressive force from the tool;
(b) running the tool into a well bore and locating the tool on a formation in the well bore;
(c) compressing the control sub by setting down weight on the tool;
(d) using the compressive force to move the obturating member and thereby control the fluid flow through the radial outlets, regulating the fluid pressure from the first outlet to hydraulically control the tool.
Preferably the method includes the step of running the tool in the well bore with the radial outlets in an open position and circulating fluid within the well bore.
Preferably the method includes the step of indexing the sleeves with respect to each other to move a pin in a sleeve within a recess of the other sleeve. Further steps may therefore include locating the pin in a position wherein the compressive force may be released and the radial ports may selectively be in an open or closed position.
Preferably also the method may include the steps of picking up and setting down the weight of the string repeatedly to cycle opening and closing of the radial outlets and thus provide a selective continuous ‘on’ and ‘off’ operation of the tool.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings of which:
FIGS. 1 ( a ) to ( d ) are a series of part cross-sectional schematic views of a control sub, according to an embodiment of the present invention, in a work string with an expander tool illustrating the operating positions of the control sub during expansion of a pipe; and
FIG. 2 is an illustration of an indexing mechanism showing the outer surface of an inner sleeve and, in cross-section, the outer sleeve of a control sub according to a further embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference is initially made to FIGS. 1 ( a ) to ( d ) of the drawings which illustrates a control sub, generally indicated by Reference Numeral 10 according to an embodiment of the present invention, in a work string 12 with an expander tool 14 illustrating the operating positions of the control sub 10 during expansion of a pipe 16 within a casing 18 of a well bore.
With specific reference to FIG. 1 ( a ), control sub 10 comprises a tubular body 20 having an outer sleeve 22 and an inner sleeve 24 . Outer sleeve 22 is of two-part construction, having an upper portion 26 and a lower portion 28 . Upper portion 26 includes a threadable portion 30 for connection of the sub 10 to a work string 12 . Upper portion 26 includes four apertures 32 circumferentially arranged around the sleeve 22 to provide access through the sleeve 22 . Lower portion 28 is threadably attached to upper portion 26 . Lower portion 28 has an inner surface 34 , which is hexagonal in cross-section. When threaded together the upper 26 and lower 28 portions of the outer sleeve 22 provide a lip 36 whose purpose will be described hereinafter.
Inner sleeve 24 includes a central bore 35 through which fluid may pass through the control sub 10 . Inner sleeve 24 has an outer surface 38 having a hexagonal cross-section to match the inner surface 34 of the outer sleeve 22 . Inner sleeve 24 further provides a threadable connection 40 at the base of the sub 10 for connection to an adapter 42 for the expander tool 14 . Beside the threadable connection 40 is located a stop 44 .
The upper end of inner sleeve 24 is threadably connected to an obturating sleeve 48 . Obturating sleeve 48 is located within the inner bore 35 of the control sub 10 . Obturating member 48 includes a matching set of apertures 50 to those apertures 32 in the outer sleeve 22 . It will be appreciated by those skilled in the art that the size and dimensions of the apertures 50 could be varied to provide a flow profile to regulate flow through the apertures 32 of the outer sleeve 22 . Further at a lower end of sleeve 48 is located a lip 46 .
In use, the control sub 10 is mounted at the end of a work string 12 by threadable connection 30 . An expander tool 14 is located onto the control sub via a threadable connection 40 with an optional adapter 42 . As seen in FIG. 1 ( a ), when mounted the lips 36 , 46 of the outer sleeve 22 and obturating sleeve 48 respectively abut so that the inner sleeve 24 and obturating sleeve 48 are supported from the outer sleeve 24 . In this first position of the obturating sleeve 48 the apertures 50 and 32 are aligned to provide a radial port for the expulsion of fluid radially from the sub 10 towards the casing 18 . This is the configuration chosen for running the work string into the well and thus fluid can circulate from the sub via the inner bore 35 and the radial port provided by the apertures 32 , 50 .
Reference is now made to FIG. 1 ( b ) of the drawings wherein the work string has been run in the well bore through the casing 18 and the expander tool 14 has now located on a pipe 16 which requires to be expanded radially. When the expander tool 14 reaches the pipe, the expander tool will be stopped and the weight of the string will bear down upon the tool such that the tool 14 provides a compressive force onto the sub 10 . The compression force will move the inner sleeve 24 relative to the outer sleeve 22 , such that the inner sleeve 24 remains static and the outer sleeve 22 is shifted relatively downwards. This shift of the sleeves 22 and 24 provides an apparent shift of the obturating sleeve 48 such that the apertures 32 , 50 are now mis-aligned. Fluid flow is now prevented from exiting the tool radially through the apertures 32 , 50 . Further fluid is prevented from escaping between the sleeves 22 , 24 by virtue of the o-rings 52 , 54 located on either side of the aperture 50 of the obturating sleeve 48 .
Reference is now made to FIG. 1 ( c ) of the drawings wherein the sub 10 is held in compression. The expander tool 14 has been pressured up and no pumping of fluid through the inner bore 35 is required to maintain the expander tool in the actuated position unless a bleed is located in the expander tool 14 . Pipe 16 is expanded by virtue of a cone 56 of the tool entering the pipe 16 and forcing the pipe to expand to a diameter equal to the actuated expander tool 14 . Expander tool 14 is operated from a constant pressure of fluid delivered through the inner bore 35 . Pipe 16 can become sealingly engaged to the casing in this operation. Alternatively, there may be annulus remaining between pipe 16 and casing 18 .
It will be appreciated by those skilled in the art that any type of hydraulically operated expander tool could be used in this configuration and thus, a full description of an expander tool is absent so as not to limit the present invention.
As the expander tool expands the pipe it maintains a compressive force on the sub 10 so that the ports 32 , 50 remain mis-aligned for the pressure to be maintained constantly through the inner bore 35 . In a preferred embodiment of the present invention there is located within the bore 35 a sensor 58 . Sensor 58 is a downhole pressure memory gauge which monitors the pressure of the hydraulic fluid through the bore 35 . This can be used to determine that a constant hydraulic pressure has been exerted on the expander tool to monitor the expansion of the pipe 16 . It will further be appreciated that if the pressure within the bore 35 requires to be adjusted, weight can be released from the string 12 thereby reducing the compressive force from the expander tool 14 such that some alignment of the apertures 32 , 50 occurs and a small radial expulsion of fluid from the sub 10 may occur to control the pressure within the bore 35 .
When the pipe 16 is fully expanded in the casing 18 the expander tool 14 can be pulled from the well by “tripping” the sub 10 on the work string 12 from the casing 18 . As the expander tool 14 does not abut the surface of the pipe 16 when the pipe 16 is expanded, as shown in FIG. 1 ( d ), there is no weight bearing facility for the expander tool 14 and thus a compressive force on the sub 10 is released. When the compressive force is released, the inner sleeve 24 drops in relation to the outer sleeve 22 and thereby causes the obturating sleeve 48 to relocate to the first position wherein the apertures 32 and 50 are now realigned to provide a radial port for hydraulic fluid within the inner bore 35 to pass from the sub 10 into the annulus created between the sub 10 and the casing 18 . Thus, as the tool 14 is pulled out of the hole, fluid can circulate within the well bore. Control sub 10 is thus in tension during this operation.
Reference is now made to FIG. 2 of the drawings, which illustrates an additional feature of the sub 10 , provided in a further embodiment of the present invention. Like parts to those of FIG. 1 have been given the same Reference Numeral but are now suffixed ‘a’.
In this embodiment the sub 10 is provided within an indexing mechanism generally indicated by Reference Numeral 60 . Indexing mechanism 60 comprises an index sleeve 62 located on the inner sleeve 24 on the sub 10 a . On the outer surface 38 a there is located a profile 64 . Profile 64 is a key providing a lower 66 circumferential arrangement of v-grooves and on every second groove there is located a longitudinal portion 68 . On the outer sleeve 22 a there is located one or more index pins 70 . In the embodiment shown there is one index pin 70 . Index pin 70 is arranged to project towards the inner bore 35 a and locate within the profile 64 . The pin 70 may move to any position within the profile 64 as long as it remains in the path provided around the lower profile 66 or is located into one of the longitudinal portions 68 .
In operation, a sub 10 a including the index mechanism 60 would be run into a casing as described herein with reference to FIG. 1 . When the tool has landed on a formation in well bore, the pin 70 , originally located in the longitudinal portion 68 , will be driven along the slot and into the circumferential portion 66 .
When the pin 70 is located at a top 72 of the longitudinal portion 68 , the radial ports (not shown) in the outer and inner sleeves 22 a and 24 a (alike to the ports 32 and 50 in the tool 10 of FIGS. 1 a to 1 d ) are aligned and fluid may circulate from the sub 10 a as described herein before.
When the index pin 70 is located within the circumferential portion 66 , the radial ports are closed as described herein with reference to FIGS. 1 ( b ) and 1 ( c ). As the circumferential slot 66 includes a number of v-grooves, each v-groove provides a cavity 74 into which the pin 70 can locate and be held relative to the sleeve 62 . When the pin 70 is located in the cavity 74 , the sub 10 a can be picked up on the string 12 a and thus the expander tool can be tripped from the well bore with the radial ports in a closed position. By compression and release of the sub in a reciprocating action, the index pin 70 can be moved around the circumferential profile 66 and thereby the position of the radial ports, can be selected to provide controlled operation of the tool 14 a.
In the embodiment shown in FIG. 2 , the sub 10 a may be picked up while the radial ports remain closed and only on every second time the tool is picked up will the ports become open by virtue of the pin moving from the cavity 74 into the slot 68 .
A principal advantage of the present invention is that it provides a control sub for a hydraulically operated downhole tool, which controls the hydraulic pressure to the tool adjacent to the sub. A further advantage of the present invention is that it provides selective operation of a hydraulically operated downhole tool while the tool is in the well bore.
By use of an indexing mechanism, a further advantage of the present invention is that it ensures that pressure is maintained upon the expander tool without the risk of the radial ports opening and thus the expander tool can be reciprocated within a well bore without loss of hydraulic pressure upon the expander tool.
Modifications may be made to the invention herein described without departing from the scope thereof. For example, it will be appreciated that any number of apertures can be arranged to provide radial expulsion of the fluid for circulation from the sub. Additionally, these ports may be arranged to expel fluid in a direction substantially upwards or downwards in relation to the casing. Further, it will be appreciated that the control sub of the present invention could be used in a well bore, which is vertical, inclined or horizontal.
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A control sub for use with a hydraulically operated downhole tool. In an embodiment, the sub comprises an outer sleeve connected to a work string and an inner sleeve slidably engaged to the outer sleeve by matching hex profiles, connected to the downhole tool. Radial ports in the outer sleeve provide selective circulation of fluid from the tool and by closing these ports with the sleeve fluid pressure in to the downhole tool can be controlled. Closure is effected by setting down weight on the sub against the tool. An indexing mechanism is also described to keep the tool in a configuration, which maintains pressure on the tool. The sub is suitable for use with an expander tool.
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BACKGROUND OF THE INVENTION
This invention relates to improvements of a synchronous belt and improvements of a method of producing the synchronous belt, and particularly relates to improvements of a cord of a synchronous belt having no facing fabric.
In power transmission belts used for office automation (OA) gears, especially in synchronous belts such as a miniature synchronous belt, there have been used for teeth two types of materials, i.e., vulcanized rubber and casting urethane elastmer. Out of these two types of materials, the latter is generally used with a cord made of aramid fibers which serves as a tension member (See Japanese Patent Application Laid-Open Gazette No.5-44181), because the aramid fiber is excellent in properties such as strength, elasticity and heat resistance. Otherwise, a cord composed of a metallic wire would be susceptible to rust and possess excessive stiffness. On the contrary, since a cord made of polyester fibers has low stiffness (small modulus of elasticity), this is unsuitable for heavy duty power transmission.
However, the synchronous belt using a cord made of aramid fibers has a problem in its use for household electrical appliances and OA gears in which the center distance between pulleys is fixed, because the cord is increased about 0.20% in length due to the absorption of moisture.
Meanwhile, a cord made of glass fibers has been also used in many rubber-made synchronous belts because of its excellent dimensional stability (See Japanese Patent Application Laid-Open Gazette No.63-76935).
In this view, it can be considered to form a cord from inorganic fibers such as glass fiber having excellent dimensional stability and use it in a synchronous belt made of casting urethane elastomer. However, such a cord formed of glass fibers have been seldom used in the synchronous belts made of casting urethane elastomer.
It can be assumed that (a) one of the reasons is that the cord is susceptible to damage from a mold at the molding and that (b) the other reason is that inter-filament parts of the cord are impregnated with casting urethane elastomer thereby rising stiffness. These two reasons (a) and (b) will discuss below in detail.
First, discussion is made about the reason (a). Since the teeth of the synchronous belt made of casting urethane elastomer cannot be coated with a facing fabric, the cord of the synchronous belt is damaged.
If a synchronous belt with a facing fabric is produced by the use of casting urethane elastomer, there may be employed the manner that rolls a facing fabric around an inner mold which has at the periphery a teeth-like forming surface for forming a bottom face of the synchronous belt, winds a cord around the facing fabric, sets outside the inner mold a cylindrical outer mold having at the inner periphery a forming surface for forming a back face of the synchronous belt and pours urethane elastomer into a space between the facing fabric and the outer mold. However, since the urethane elastomer has a low viscosity to pass through textures of the facing fabric, it is impossible to press the facing fabric against the teeth-like forming surface of the inner mold. Therefore, whereas most of rubber-made synchronous belts each have teeth coated with a facing fabric, there can be obtained no synchronous belt made of urethane elastomer which has teeth coated with a facing fabric.
Therefore, the synchronous belts are produced with no facing fabric provided, so that, in many cases, the portions of the cord located at bottom lands are not coated with urethane elastomer to be exposed. Meanwhile, on the teeth-like forming surface of the inner mold, projections are formed for preventing the displacement of the cord. When the molded synchronous belt is removed from the inner mold, the cord may be damaged by the projections of the inner mold.
Next, discussion is made about the reason (b). In the formation of the synchronous belt made of urethane elastomer, urethane elastomer is generally poured under a reduced pressure for ease of the pouring and for degassing, so that casting urethane elastomer is entered to inter-filament parts of the cord thereby extremely hardening the cord. Such hardened cord is readily broken and readily generates heat at the belt run.
SUMMARY OF THE INVENTION
An object of the present invention is, in a synchronous belt having no facing fabric at its bottom face, to prevent a cord from being impregnated with low-viscosity urethane elastomer for forming teeth and a back layer by subjecting the cord to adhesion treatment at the stage that the cord is in strands and the stage after it is twisted, thereby ensuring the flexibility of the cord to accomplish a long life of the belt. Another object of the present invention is to avoid the contact of the cord with a mold at the molding of the belt by coating the cord with the adhesive thereby securely preventing fibers of the cord from being damaged due to the contact with the mold.
<Synchronous belt>
To attain the above object, a synchronous belt of the present invention comprises: a tension member composed of a cord extending over the belt length; a plurality of teeth fixedly provided on one side of the tension member at set intervals in a longitudinal direction of the belt; and a back layer bonded to the other side of the tension member, wherein the back layer and the teeth are so formed that urethane elastomer is subjected to cast molding, the urethane elastomer forming the teeth is exposed at each bottom land, the cord forming the tension member is made of inorganic fibers, and the cord is so formed as to be impregnated with a water based latex adhesive and then coated with a film of an epoxy adhesive.
In the present invention, the film of an epoxy adhesive avoids the urethane elastomer from entering the inside of the cord at the time of cast molding to prevent the cord from increasing in stiffness due to the entrance of the urethane elastomer. Further, the film of an epoxy adhesive protects the inorganic fibers of the cord against being damaged by projections of an inner mold. In addition, the water based latex adhesive with which the cord is impregnated ensures the flexibility of the cord to enhance the durability of the synchronous belt. In detail, when the synchronous belt is run under heavy load for a long time, the cord is repeatedly flexed with a heavy strength. However, the synchronous belt of the present invention is hard to be broken because of the flexibility contributed by the water based latex adhesive.
As the inorganic fiber, there can be used a carbon fiber, and particularly there can be suitably used a glass fiber. Suitable for such a glass fiber is a fiber made of high-strength glass such as E-glass (no-alkaline glass). For example, there can be suitably used a glass-fiber strand so formed that two hundred glass fibers with a filament diameter of 7 μm to 9 μm are bound by a binder. However, an inorganic fiber to be used in the present invention is not limited to the above-mentioned types of fibers.
As the water based latex adhesive, there can be suitably used a mixed solution of blocked isocyanate dispersion and a resorcine formaldehyde rubber latex liquid (hereinafer, referred to as an RFL liquid).
As the blocked isocyanate, there can be suitably used blocked isocyanate so formed that polyisocyanate having three or more isocyanate groups in every molecule is blocked by lactam or oxime.
Here, the above polyisocyanate having three or more isocyanate groups in every molecule means (a) a single multifunctional isocyanate compound such as a triisocyanate compound, or (b) a mixture of the above multifunctional isocyanate compound and diisocyanate and/or monoisocyanate.
Examples of the multifunctional isocyanate compound of (a) are triisocyanates such as triphenylmethane-4,4',4"-triisocyanate, butane-1,2,2-triisocyanate, a trimethylolpropane tolylene diisocyanate addition product (e.g., "Desmodur L" produced by Bayer A. G.) and 2,4,4'-diphenylether triisocyanate.
The mixture of (b) is expressed by the following general formula: ##STR1## wherein n is 0, 1, 2, 3, 4 or more.
As the mixture of (b), there can be used polymethylene polyphenyl isocyanate (PAPI) or the like.
The blocked isocyanate of the present invention is formed by reacting one or more types of above-mentioned polyisocyanate and one or more types of lactam or oxime in a well-known manner. Examples of the lactam are propiolactam, butyrolactam, caprolactam and valerolactam. On the other hand, examples of the oxime are acetoxime, methyl ethyl ketone oxime, cyclohexanone oxime and benzophenone oxime.
The RFL liquid to be used in the present invention is a mixed water solution of a precondensate obtained by reacting resorcine and formaldehyde through acid or alkaline catalyst and one or more types of latex selected out of styrene-butadiene latex, carboxyl group-contained styrene-butadiene latex, styrene-butadiene-vinylpyridine latex, acrylonitrile-butadiene latex, polychloroprene latex, polybutadiene latex and natural rubber latex. The mole ratio of resorcine with respect to formaldehyde is preferably within the range of 0.5 to 4. The mixture ratio of the resorcine-formaldehyde precondensate and the latex is preferably within the range of 2:98 to 15:85 in a unit of weight ratio of solid part.
An important ingredient in the above-mentioned adhesive is an isocyanate ingredient of blocked isocyanate. It is essential that the isocyanate compound is polyisocyanate having three or more isocyanate groups per molecule. In the case of using an isocyanate compound which has only two or less isocyanate groups per molecule, e.g., diisocyanate such as diphenylmethane diisocyanate, tolylene diisocyanate and hexamethylene diisocyanate or monoisocyanate such as phenyl isocyanate, it is difficult to attain the objects of the present invention. The reason for this can be assumed that if a three-dimensional network structure is formed by using polyisocyanate molecules having three or more functional groups, this is effective at increasing the adhesive in heat resistance.
As a blocking agent for the blocked isocyanate, there are commonly known phenols, aliphatic alcohols and amines in addition to the above-mentioned types of lactam and oxime. Since the above blocking agents other than lactam and oxime are unsuitably high in dissociation temperature and cause damage to polyester after dissociation, they are not preferable for use in the present invention.
The water based latex adhesive is preferably prepared in such a manner that the blocked isocyanate dispersion and the RFL liquid are mixed so as to be 1:9 to 4:6 in weight ratio of solid part. In this manner, the synchronous belt is adjusted to the correct stiffness while obtaining an adhesion effect on inorganic fibers forming the cord. In other words, if the weight ratio of solid part is less than 1:9, the adhesion effect is insufficient. On the contrary, if the weight ratio of solid part is more than 4:6, the cord becomes disadvantageously hard.
A solids content of the water based latex adhesive is preferably within the range of 20 to 30 wt % with respect to the total weight of a material for cord and the solid part of the water based latex adhesive. Within this range, the inorganic fibers can be evenly impregnated with the latex adhesive thereby advantageously preventing the later entrance of epoxy adhesive.
A solids content of the epoxy adhesive is preferably within the range of 3 to 8 wt % with respect to the total weight of the material for cord, the solid part of the water based latex adhesive and the solid part of the epoxy adhesive. Within this range, the cord can be coated with a film having a suitable thickness for preventing the entrance of urethane elastomer and for preventing the damages of the cord.
As an epoxy compound for the epoxy adhesive, there can be preferably used a polyepoxy compound having two or more epoxy groups per molecule. Examples of such a polyepoxy compound are a product formed by the reaction of polyhydric alcohol such as ethylene glycol, glycerin, sorbitol and pentaerythritol or polyalkylene glycol such as polyethylene glycol with a halogen-contained epoxy compound such as epichlorohydrine, and a product formed by the reaction of polyhydric phenol such as resorcin and bis(4-hydroxyphenyl) dimethyl ethane or phenol resin such as phenol-formaldehyde resin and resorcin-formaldehyde resin with a halogen-contained epoxy compound such as epichlorohydrine.
<Method of producing a synchronous belt>
The above synchronous belt can be produced in the following method.
In detail, the method is for producing a synchronous belt which comprises a tension member, a plurality of teeth fixedly provided on one side of the tension member at set intervals in a longitudinal direction of the belt and a back layer bonded to the other side of the tension member. This method comprises the steps of: impregnating a strand made of inorganic fibers with a water based latex adhesive; twisting a plurality of the strands impregnated with the water based latex adhesive to form a material for cord; applying an epoxy adhesive to the material to form a cord whose surface is coated with a film of the epoxy adhesive; winding the cord spirally around an inner mold whose outer periphery is a teeth-like forming surface for forming a bottom face of the synchronous belt; setting, outside the inner mold around which the cord is wound, a cylindrical outer mold whose inner periphery is a forming surface for forming a back face of the synchronous belt; and pouring a liquid of urethane elastomer into a cavity between the inner mold and outer mold and then heat-hardening it.
A suitable inorganic fiber is a glass fiber.
The impregnation treatment with the water based latex adhesive may be conducted in such a manner that two parallel-arranged strands are impregnated with the latex adhesive by means of spraying, dipping, coating or the like and then the strands are subjected to common heat treatment, for example, in which they are passed through hot wind. The heat treatment is preferably conducted at a temperature of 200° to 350° C. for 1 to 10 minutes.
For the water based latex adhesive, there can be suitably used a mixture of blocked isocyanate dispersion and an RFL liquid. Preferably, the blocked isocyanate dispersion and the RFL liquid are so mixed that they are 1:9 to 4:6 in weight ratio of solid part.
Further, the impregnation treatment is preferably conducted so that a solids content of the water based latex adhesive is 20 to 30 wt % with respect to the total weight of the material for cord and the solid part of the latex adhesive.
In the adhesion treatment with the epoxy adhesive, there is no particular limitation to an organic solvent for the adhesive. For this organic solvent, suitably used are aromatic hydrocarbon such as benzene, xylene and toluene, aliphatic ketone such as methyl ethyl ketone and methyl isobutyl ketone, and ester such as ethyl acetate and amyl acetate. Such solvent adhesives are not particularly limited in concentration of solid part. The concentration of solid part is preferably within the range of 10 to 50 wt %.
The adhesion treatment with the epoxy adhesive is conducted in the common manner after the impregnation treatment is conducted with the water based latex adhesive. In detail, the adhesion treatment is conducted in such a manner that the material for cord is dipped into an adhesive composition in which the epoxy adhesive is dissolved in a solvent, is retrieved and is then as necessary subjected to heat treatment. Thus, a film is formed on the surface of the cord. It is essential only that the heat treatment is conducted to the extent that the adhesive composition applied to the fibers is fixed by reaction. In general, the heat treatment may be conducted at a temperature of 250° C. or less, e.g., at 120° to 250° C., for several minutes.
A solids content of the epoxy adhesive to the material for cord is suitably 3 to 8 wt % in weight ratio of solid part.
Preferably, a set primary twist is given to the strand to which the water based latex adhesive is applied, a set of two to five strands thus twisted are parallel-arranged, a final twist opposite in direction to the primary twist is given to the set of strands thereby forming a material for cord, and then the epoxy adhesive is applied to the material.
In case of a cord to which the epoxy adhesive is not applied, low-viscosity urethane elastomer enters the inter-filament parts of the cord in molding the belt so that the cord is significantly hardened thereby degrading flex fatigue resistance. However, according to the present invention, the film of the epoxy adhesive formed on the cord surface prevents the entrance of the urethane elastomer, and eliminates the unevenness in adhesive strength of the inorganic fibers and the decrease in flex fatigue resistance of the inorganic fibers.
Further, the epoxy compound of the epoxy adhesive is resinified at the vulcanization of the urethane elastomer to enhance the adhesive strength of the film to the inorganic fibers such as glass fibers, and reacts with methylol groups contained in the RFL liquid of the water based latex adhesive to form a tight film.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view partially showing a synchronous belt.
FIG. 2 is a sectional view partially showing a casting mold and the synchronous belt in molding the belt.
FIG. 3 is an explanatory diagram of the measurement of a belt life.
FIG. 4 is an explanatory diagram of the measurement of dimensional change of the belt due to the absorption of moisture.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is not limited to the below-mentioned embodiments.
(Structure of a synchronous belt)
As shown in FIG. 1, a synchronous belt A is composed of a back layer 1, a plurality of teeth 2 and a cord 3. The plural teeth 2 are integrally provided on a surface of a cord 3 as a tension member (on the underside of FIG. 1). The back layer 1 is formed on the other surface of the tension member. The bottom face of the teeth 2 are not covered with a facing fabric.
(Treatment of a cord)
Conditions of treatment to respective cords of Samples 1 to 8 are shown in the below-mentioned Table 1. Since the details of the treatment are common to Samples 1 to 8, only Sample 1 is exemplified and explanation is omitted on other Samples 2 to 8.
Two glass strands of ECG150 type under the Japanese Industrial Standards are parallel-arranged, are dipped, for five seconds, into a treatment liquid of a blocked isocyanate-RFL mixed adhesive (hereinafter, referred to as a first adhesive) prepared as below and are then subjected to heat treatment in heated air of 220° C. for 90 seconds.
The first adhesive is a water based latex adhesive which is so formed that 400 parts of dispersion of polymethylene polyphenyl isocyanate ("Millionate MR" produced by Nippon Polyurethane Industries Co., Ltd.) blocked by ε-caprolactam as blocked isocyanate dispersion is mixed with 600 parts of an RFL liquid.
The blocked isocyanate dispersion is so prepared that 0.6 parts of methylcellulose, 0.3 parts of sodium alkyl sulfonate, 0.1 parts of polyethyleneglycol monolaurylate and 20 parts of ε-caprolactam-blocked polymethylene polyphenyl isocyanate are added to 79 parts of water and are then crushed by a ball mill for 24 hours.
The RFL liquid is so obtained that 5.7 parts of resorcine, 6.3 parts of 37% formaldehyde water solution and 3 parts of 100% caustic soda water solution are added to 185.7 parts of water and matured at 30° C. for 6 hours and then to the resulting liquid there are added 175.7 parts of butadiene-styrene-vinylpyridine latex having 41% solid part ("Nipol 2518FS" produced by Nippon Zeon Co., Ltd.) and 23.8 parts of water.
In the glass strands thus obtained, an amount of application of solid part (a solids content) of the first adhesive was 25%.
The glass strands were primary-twisted 16 times per 10 cm in Z direction to be formed into a primary twist yarn. Three primary twist yarns thus obtained were parallel-arranged, and were final-twisted 16 times per 10 cm in S direction opposite to the primary-twisting direction to be formed into a glass cord as a material for cord. Thereafter, the material for cord was subjected to adhesion treatment with an epoxy compound (epoxy adhesive) as a second adhesive. In detail, the material for cord was dipped into a treatment liquid in which a bisphenol. A type epoxy resin and an amine hardener are dissolved in an organic solvent and then dried. An amount of application of solid part of the epoxy adhesive was 4 wt %.
(Molding of a synchronous belt)
As shown in FIG. 2, the cord 3 obtained through the above two stages of adhesion treatment was spirally wound around an inner mold 5 of a casting mold 4, and then an outer mold 7 was set outside the inner mold 5. Thereafter, casting urethane elastomer was poured into a cavity between the inner and outer molds 5, 7 under a reduced pressure, was degassed and was then heat-hardened thereby obtaining a synchronous belt A.
In the inner mold 5, there is formed a teeth-like forming surface 6 corresponding to the shape of the bottom face of the synchronous belt A. At a top end of each tooth of the forming surface 6, a projection 6a is linearly provided in a belt width direction.
(Cord of Sample 9)
Sample 9 used a cord obtained by subjecting a final twist yarn made of aramid fibers of 400de/1×3 ("KEVLAR" produced by Du Pont) to adhesion treatment with EX521 which is an epoxy adhesive commercially available from Nagase Sangyo K.K. An amount of application of solid part of the epoxy adhesive was 5 wt %.
(Evaluation of synchronous belts)
The below-mentioned Table 1 shows test results of respective synchronous belts A formed by use of the above sample cords. Test details on evaluation items of Table 1 are as follows.
<Index of belt damage due to mold>
This index depends on a state of the film formed on a cord surface by the second adhesive. When the molded synchronous belt was peeled off from the inner mold and was then cut to a set width in a belt length direction, a state of filaments of the cord was graded. 0 indicates filaments have no breakage, 1 indicates filaments are slightly damaged and 2 indicates many filaments are broken.
<Index of belt stiffness (value of EI), unit: Ncm 2 >
This index is for examination about how much the second adhesive entered the cord depending on an amount of application of the first adhesive. In the case of small amount of application of the first adhesive, casting urethane elastomer enters the cord to harden the belt. The same thing also occurs in the case of large amount of application of an overcoat (second adhesive). For measurement, an Olsen bending stiffness tester was used. The index of stiffness of a synchronous belt having S-shaped teeth and a 3 mm tooth pitch (hereinafter, referred to as S3M type) and using "Kevlar" as fibers for cord is 1.01 Ncm 2 , and the index of stiffness of an S3M type synchronous belt using glass fibers as fibers for cord is 1.31 Ncm 2 .
<Adhesive strength of a cord (N)>
This value shows a static adhesive strength of a cord of a synchronous belt A. The value of the S3M type belt using "Kevlar" as fibers for cord is 83.2N, and the value of the S3M type belt using glass fibers as fibers for cord is 94N.
<Belt life (hr)>
Each synchronous belt A for test sample is an S3M type one and a 60 mm width×a 486 mm length in size. The synchronous belt of this type was set to a biaxial running tester shown in FIG. 3 so as to be wound between an S3M type driving pulley 11 of a 20 mm diameter and an S3M type driven pulley 12 of a 38 mm diameter, and was run at 2500 rpm under conditions that a 6.6 kg weight was assigned in a direction of an arrow F1 and a 400 W load was applied.
<Dimensional changing ratio of belt due to absorption of moisture (%)>
Each synchronous belt A for test sample is an S3M one and a 60 mm width×a 486 mm length in size. The synchronous belt of this type was set to a biaxial running tester shown in FIG. 4 so as to be wound between an S3M type driving pulley 13 of a 30 mm diameter and an S3M type driven pulley 14 of a 30 mm diameter, and was run at 2500 rpm under conditions that a 6.6 kg weight was assigned in a direction of an arrow F2 and a 400 W load was applied. Supposed that Lo is a central distance of the synchronous belt A after aging at 55° C. for 24 hours and L is a central distance of the same type synchronous belt A after aging at 45° C. for 24 hours under 95% relative humidity. The dimensional changing ratio was measured according to the following formula.
Dimensional changing ratio (%)=((Lo-L)/Lo)×100
Further, respective amounts of application of solid part of the first and second adhesives in Table 1 were obtained in the below-mentioned manner.
<Amount of application of solid part of the first adhesive (%)>
A glass cord treated with the first adhesive was burned at 700° to 800° C. and then the remaining weight of the glass cord was calculated according to the following formula:
((w.sub.1 -w.sub.0)/w.sub.1)×100=A (wt %)
wherein W 1 is a weight of the glass cord treated with the first adhesive, W 0 is a weight of the glass cord after the burning and A is an amount of application of solid part of the first adhesive to the glass cord.
<Amount of application of solid part of the second adhesive (%)>
An amount of application of solid part of the second adhesive to the glass cord was calculated according to the following formulae:
((W.sub.2 -W.sub.0)/W.sub.2)×100=B (wt %); and
B-A=C
wherein W 2 is a weight of the glass cord treated with the first and second adhesives, W 0 is a weight of the glass cord after the burning, B is a total amount of application of solid part of the first and second adhesives and C is an amount of application of solid part of only the second adhesive to the glass cord.
With regard to Sample 9 using "KEVLAR" of 400de/1×3, a weight of a cord per set length was previously measured, the cord was treated with an epoxy adhesive and dried, and then the amount of application of solid part of the epoxy adhesive was calculated.
TABLE 1__________________________________________________________________________ Samples 1 2 3 4 5 6 7 8 9__________________________________________________________________________Ratio of NCO content in First 10 20 5 50 10 10 10 10 --Adhesive (%)Amount of Application of Solid 25 25 25 25 10 35 25 25 --Part of First Adhesive (wt %)Amount of Application of Solid 4 4 4 4 4 4 2 8 --Part of Second Adhesive (wt %)Index of Belt Damage 0 0 0 0 1 0 2 0 0Adhesive Strength of Cord (N) 95 90 60 95 95 60 65 95 83Index of Belt Stiffness 1.31 1.4 1.2 3.0 4.0 1.4 1.0 3.0 1.1(Value of IE:Ncm.sup.2)Belt Life (hr) 20 20 2 3 3 2 1 2 7Dimensional Changing Ratio 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.20of Belt due to Absorption ofMoisture (%)__________________________________________________________________________
The following are evident from Table 1.
Samples 1 and 2 obtained satisfactory results in all the evaluation items.
Sample 3 is small in ratio of NCO (isocyanate group) content of the first adhesive to be lack in adhesive strength thereby resulting in a short belt life.
Sample 4 is large in ratio of NC) content of the first adhesive, so that while it has good adhesive strength, belt stiffness is large thereby resulting in breakage at an early stage.
Sample 5 has small amount of application of the first adhesive so that epoxy resin of the second adhesive enters between filaments of a glass cord. This decreases a real amount of application of the second adhesive on the cord surface, that is, the film is thinned, so that the cord is damaged when the synchronous belt A is retrieved from the inner mold. In addition, since the epoxy resin enters between the filaments of the glass cord, cord stiffness or belt stiffness is increased. Due to these two factors, the belt is broken at an early stage.
Sample 6 is as large as 35% in amount of application of the first adhesive so that blister is generated when the glass strand is treated with the first adhesive thereby presenting a nonuniform cord surface. Accordingly, glass filaments are not entirely coated so that the adhesive strength of the cord and the belt running life are decreased.
Sample 7 has small epoxy amount of the second adhesive so that the glass cord surface is not entirely coated. As a result, the cord is damaged when the belt is retrieved from the inner mold as well as the cord has small adhesive strength to casting urethane elastomer, thereby resulting in a short belt life.
On the contrary, Sample 8 has large epoxy amount of the second adhesive. In this case, the belt is significantly hardened so that the mesh of the belt with pulleys is bad thereby resulting in a short belt life.
Sample 9 is a belt using "KEVLAR" as fibers for cord. Whereas this belt has good adhesive strength, its change in dimension is very large due to the absorption of moisture so that the belt is hard to be aligned with pulleys.
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A synchronous belt of the present invention has a tension member in the form of a cord, a plurality of teeth fixedly provided on one side of the tension member at set intervals in a longitudinal direction of the belt and a back layer bonded to the other side of the tension member. The back layer and the teeth are formed of urethane elastomer. The tension member is formed of inorganic fibers and is impregnated with a water based latex adhesive. A film of an epoxy adhesive is formed on the surface of the tension member.
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BACKGROUND OF THE INVENTION
This invention relates, in general, to a portable window sash support and, in particular, to a portable window sash support to be used with tilt type double hung window sashes to prevent damage to the tilted sash, the track mechanism which allows the sash to tilt in, damage to the vinyl or wood sash, insulated glass seals and the finish of the window sill itself.
DESCRIPTION OF THE PRIOR ART
In the prior art various types of devices which can be used with windows have been proposed. For example, U.S. Pat. No. 2,407,837 discloses a stop which is designed to hold a vertically sliding window in a partially raised position. The stop consists of a pole having a spring biased clip which will allow the clip to be moved to any position along the pole and held in position by the clips resiliency. The clip has a projection portion which engages the bottom of the window to hold the window in position.
U.S. Pat. No. 2,506,508 discloses a telescoping stop for a vertically sliding window which holds the window in a partially raised position. The stop has a series of notches which allow the height of the stop to be adjusted to hold the window in a variety of positions.
U.S. Pat. No. 2,766,960 discloses a portable holding device for holding open a vehicle trunk. The holding device has a first part adapted to be clamped to a part of the vehicle and an elongated rod pivotably mounted thereto. The rod is designed to be adjusted to different heights and different angles with respect to the first part.
U.S. Pat. No. 4,973,093 discloses a device for securing a door consisting of a vertical shaft, one end of which is secured to the door handle and the opposite end has a pad which is secured to the floor.
However, none of the prior art devices have been designed to support a tilt-in window to aid in holding the window at the proper height so a person can clean the window in an efficient and safe manner.
The new type of "tilt-in" double hung sash windows were created so a person could clean the outside glass from the inside of the house. While this type of window solves a very real problem for the homeowner, it also creates another. When it is time to clean the outside of the window, the homeowner must support the tilted in window sash with one hand and clean it with the other, because there is at present, nothing to hold the window in a convenient, horizontal position for cleaning.
When a person wants to clean the upper and lower windows, the lower window is tilted in first, then the upper window is tilted in on top of the lower window. Supporting the combined weight of both windows can be a formidable task, especially in view of the fact that modern windows may contain double or even triple pane glass.
If the sashes are allowed to go to the full downward tilted in position, which occurs when the bottom sash comes into contact with the inside window sill, the leverage created by this arrangement exerts a tremendous amount of pressure on the tilted sash (at the point of contact with the window sill) and the track mechanism which allows the window to tilt in. This arrangement can cause damage to the vinyl or wood sash, the insulated glass seals, or the finish of the sill itself. Another problem is the very expensive glass, that is in the window, may break.
In the case of larger windows, it is impossible to support the lower sash with one hand and unlock the upper sash so it can be tilted in. The operation necessary to unlatch the windows requires the use of both hands.
SUMMARY OF THE INVENTION
The present invention comprises a pair of supports with a platform at the top of each support. The platforms hold the top and bottom tilt in type windows so they can be easily cleaned. The top support also has a clamp to make it easier to hold the bottom window.
It is an object of the present invention to provide a portable window support for tilt-in windows.
It is an object of the present invention to provide a portable window support which protects the window when it is in the tilted-in or cleaning position.
It is an object of the present invention to provide a portable window support which is inexpensive and easy to use.
These and other objects and advantages of the present invention will be fully apparent from the following description, when taken in connection with the annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one of the supports of the present invention.
FIG. 2 is a perspective view of the other support of the present invention.
FIG. 3 is a side view of the present invention holding a pair of windows.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings in greater detail, FIG. 1 shows a base support 1 which consists of tube with a central aperture 2 generally centrally disposed. The tube could be made from any generally rigid material such as, but not limited to, metal or plastic. The support has an aperture 5 in one side, which extends through to the other side, for purpose to be explained below. Attached to one side of the support 1 is a support platform 3, which can be covered with a cushioning material (not shown) such as rubber or plastic to protect the tilt-out window.
The support platform 3 can be supported by a brace 4 secured between the platform and the side of the support 1. The support 1 has a base 7 which should be wider than the support to provide a stable support when a window is placed on the platform 3. The support 1 can be secured at the bottom by braces 6 which are similar to brace 4 for the platform 3. Attached to the base 7 is four pads 8 to protect the floor surface, that the window helper may be placed on, from scratches.
It should be noted that the support 1, platform 3 and the braces 4 and 6 are shown as separate elements that can be attached by any conventional means. However, all of the elements could be molded as a unitary structure without departing from the scope of the invention.
The second part of the window helper is shown in FIG. 2, and consists of a second tube 9 with an outside diameter which will fit snugly into the aperture 2 in support 1. The fit between the two supports should be snug, but also, the support 9 should be able to move without too much resistance so that it will be difficult to slide up and down in support 1. An aperture 10 is positioned in the side of support 9, and extends through to the other side, and which will register with aperture 5 when the two supports are telescoped. In this manner, a pin (not shown) can be placed in the aligned apertures to hold the two supports in assembled condition.
The second support 9 has a support platform 11 and brace 12 which are similar to platform 3 and brace 4 on the support 1, and that serve the same purpose. In addition, an adjustable vise is attached to the support 9 just below the platform 11. The vise consists of a base 13 which has a threaded aperture therethrough. Secured within the aperture is a threaded shaft 15 which has a protective pad 16 on one end and a turning knob 14 on the opposite end. When a window 18 (see FIG. 3) is placed between the platform 3 and the knob 14 is tightened, the window 18 will be held securely while the window 17 is cleaned.
The support 1 is approximately 36 inches tall and the aperture 5 is 3/8 inches in diameter, and is placed in the center of the support 1 about 2 inches from the top. Support 9 is 28 inches tall and even on all sides, and the aperture 10 is about 10 inches from the top of the support. The vise should be placed about 5 inches above the aperture 10. The platform 3 extends about 3 inches from the side of support 1, and the platform 11 extends about 41/2 inches from the side of the support 9. However, it should be understood that the above dimensions are given as illustrations only, and the dimensions could be changed without departing from the scope of the invention.
In order to use the window helper, a user would raise the bottom window 18 up about 3 inches and bring the top window 17 down about 11 inches from the bottom of the window sill. The inside of the bottom window 18 can now be cleaned, and then the bottom window can be tilted out and allowed to rest on the top of platform 3 and the outside of the bottom window can now be cleaned. The support 1 will hold the bottom window in a horizontal position so the user can have both hands free to clean and he/she does not have to support the bottom window with one hand while cleaning with the other hand.
After the bottom window 18 has been cleaned, the inside of the top window 17 can be cleaned. Next, the bottom window can be raised enough to unlock the top window, and tilt it into the room. Both windows can now be rested on the platform 3 temporarily. Now top window 17 will be raised while support 9 is placed into the aperture 2 in support 1. The top window can now be placed on platform 11, the apertures 5 and 10 can be aligned and a pin can be inserted into the apertures to secure the two supports. Knob 14 can now be turned which will force pad 16 against the top of window 18, thereby securely holding window 18 against the platform 3, as shown in FIG. 3. The outside of window 17 can now be cleaned. Once cleaned the process can be reversed and the windows tilted back into the window frame.
Although the Window Helper and the method of using the same according to the present invention has been described in the foregoing specification with considerable details, it is to be understood that modifications may be made to the invention which do not exceed the scope of the appended claims and modified forms of the present invention done by others skilled in the art to which the invention pertains will be considered infringements of this invention when those modified forms fall within the claimed scope of this invention.
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A pair of supports with a platform at the top of each support. The platforms hold the top and bottom tilt in type windows so they can be easily cleaned. The top support also has a clamp to make it easier to hold the bottom window while cleaning the top window.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 12/128,265, filed May 28, 2008, this application is also a Continuation-In-Part of U.S. patent application Ser. No. 13/743,418 filed Jan. 17, 2013, now U.S. Pat. No. 8,540,498 issued Sep. 24, 2013, which is a Divisional of U.S. patent application Ser. No. 12/047,938, filed Mar. 13, 2008, now U.S. Pat. No. 8,360,744, issued Jan. 29, 2013, Priority is claimed from all of the above identified applications and all are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a control scheme. More particularly the present invention relates to a method and apparatus for reducing a shaft power required when starting up a turbocompressor by manipulating the compressor's antisurge recycle valve.
[0004] 2. Background Art
[0005] As shown in FIG. 1 , a turbocompressor 100 , whether axial or centrifugal, is driven by a driver such as a variable speed electric motor 110 . A recycle valve 120 , used for antisurge protection, is piped in parallel with the compressor 100 . An inlet throttling valve 130 may be used for compressor capacity or performance control.
[0006] As all those of ordinary skill in this art know, surge is an unstable operating condition of a turbocompressor encountered at generally low flow rates. The surge region is shown in FIG. 2 to the left of the surge limit curve 210 . In FIG. 2 , H p is the polytropic head and Q is the volumetric flow rate, both associated with the turbo compressor.
[0007] For the purposes of this document, including the claims, the compressor's minimum operating speed is hereby defined as the minimum rotational speed, greater than idle speed, at which the compressor may be operated continuously. The minimum operating speed is defined by the compressor manufacturer. It is generally depicted as the lowest performance curve in a compressor performance map such as shown in FIGS. 2 and 3 . Lower speeds, greater than idle speed, are experienced on startup and shutdown, but the compressor is not operated continuously at these speeds. For turbocompressors operated at a constant speed, such as those driven by constant speed electric motors, the minimum operating speed is simply the constant operating rotational speed.
[0008] As those of ordinary skill know, the accepted startup procedure for a turbocompressor is to increase the rotational speed of the compressor with the antisurge valve 120 wide open until the compressor reaches the compressor's minimum operating speed (if the compressor is operated at variable speed) or the compressor's operating speed (if the compressor is driven by a constant speed driver). At this point in the startup procedure, the antisurge valve 120 is ramped closed and the compressor's 100 automatic performance control takes control of the compressor's rotational speed, inlet throttling valve 130 , or variable guide vanes to control the compressor's 100 capacity.
[0009] As is recognized by all those of ordinary skill, this startup procedure provides the most safety for the compressor because surge will be avoided, as depicted in FIG. 3 . The compressor's 100 operating point trajectory 320 is shown as a dot-dashed line. Curves of constant compressor rotational speed 310 a - 310 e are shown as solid lines. The curve 310 a represents the minimum operating rotational speed, while the curve 310 e represents the maximum operating rotational speed. Because the recycle valve 120 is maintained in its fully open position until minimum rotational speed has been achieved, the compressor operating point trajectory 320 tends to give wide berth to the surge limit curve 210 in the region below the minimum rotational speed curve 310 a.
[0010] Additional impetuses for startup with the antisurge valve 120 fully open are that the surge limit curve 210 is usually unknown for rotational speeds less than the minimum operating speed, and that pressure and flow sensor signals of reasonable magnitude must be achieved before a valid compressor operating point may be determined. The compressor's operating point must be calculated to compare its location to the surge limit line 210 , or surge control line 220 to avoid having the compressor's operating point cross the surge limit line 210 . Antisurge control algorithms are described in the Compressor Controls Series 5 Antisurge Control Application Manual, Publication UM5411 rev. 2.8.0 December 2007, herein incorporated in its entirety by reference.
[0011] Due to the large flow through the compressor 100 during startup using the above standard procedure, the shaft power required to drive the compressor 100 is large. This results in slower startup and, possibly, tripping of the driver due to power overload.
[0012] A gas turbine driver may experience high exhaust gas temperatures during the startup of a turbocompressor. An electric motor driver may trip on thermal overload due to a current being too high for too long a duration.
[0013] There is, therefore, a need for an improved control strategy for the startup of turbocompressors to reduce the loading of the compressor while maintaining the compressor flow out of the unstable, surge region.
BRIEF SUMMARY OF THE INVENTION
[0014] An object of the present invention is to provide a method and apparatus for safely starting a turbocompressor while minimizing an overall energy required to accomplish the startup.
[0015] Compressors having gas turbine drivers and variable frequency drive electric motors tend to have long startup times—on the order of several minutes. For this class of compressors, a first embodiment of this invention prescribes that the compressor's antisurge valve be maintained at its fully open position until predetermined signal strengths are realized from the compressor's suction and discharge pressure sensors, and the flow sensor. At this point, the antisurge valve is ramped closed at a predetermined rate under control of the antisurge control system to keep the compressor's operating point from crossing the surge control curve. Startup continues independently of the antisurge controller's operation.
[0016] A second class of compressors comprises constant-speed electric motor driven compressors. The startup times for this class of compressors tend to be on the order of less than a minute. In this case, the control system starts the antisurge valve in a fully open position, and begins to ramp the antisurge valve closed at a predetermined rate after a predetermined time has elapsed after the initiation of the startup of the compressor. Because of the rapid startup, the pressure and flow sensor signals become viable very quickly, so antisurge control may be carried out before the compressor's operating point reaches the surge control curve.
[0017] The novel features which are believed to be characteristic of this invention, both as to its organization and method of operation together with further objectives and advantages thereto, will be better understood from the following description considered in connection with the accompanying drawings in which a presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood however, that the drawings are for the purpose of illustration and description only and not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0018] FIG. 1 is a schematic of a compressor, driver, and antisurge recycle valve;
[0019] FIG. 2 is a first representative compressor performance map;
[0020] FIG. 3 is a second representative compressor performance map showing a first compressor operating point's startup trajectory;
[0021] FIG. 4 is a is a third representative compressor performance map showing lines of constant shaft power;
[0022] FIG. 5 is a fourth representative compressor performance map showing a second compressor operating point's startup trajectory;
[0023] FIG. 6 a is a schematic of a variable speed motor driven compressor system;
[0024] FIG. 6 b is a schematic of a constant speed motor driven compressor system;
[0025] FIG. 7 is a schematic of a turbine driven compressor system;
[0026] FIG. 8 is a flow diagram of a first embodiment of the present invention;
[0027] FIG. 9 is a flow diagram of a second embodiment of the present invention;
[0028] FIG. 10 is a flow diagram of a third embodiment of the present invention; and
[0029] FIG. 11 is a detail flow diagram of a startup initiation process
DETAILED DESCRIPTION OF THE INVENTION
[0030] A typical compressor performance map in H p -Q coordinates is shown in FIG. 4 . Here, H p is polytropic head and Q is volumetric flow rate—usually in the suction. The map of FIG. 4 comprises solid-line curves of constant rotational speed 310 a - 310 e and dashed-line curves of constant shaft power 410 a - 410 e . As is clear from the relationship between the curves of constant rotational speed 310 a - 310 e and the curves of constant shaft power 410 a - 410 e , at a given rotational speed, the required shaft power decreases as the operating point moves toward the surge limit 210 . To avoid overpowering the compressor driver 110 , 710 (see FIG. 7 ) an operating point trajectory 520 , shown in FIG. 5 , running as near the surge limit 210 as possible, should be used. The short-dashed curve 510 represents a surge control line—a line set a predetermined distance from the surge limit line 210 toward the stable operating region, thus providing a safety margin for the antisurge control system.
[0031] As those of ordinary skill in the art of compressor control know, limit control is applied to the compressor 100 to maintain the operating point at or to the right of the surge control line 510 . To effect this control, an antisurge or recycle valve 120 , as shown in FIGS. 1 , 6 a , 6 b , and 7 , is manipulated to maintain an adequate flow rate through the compressor 100 . The manipulation of the antisurge valve 120 is carried out via an automatic control algorithm, such as a closed loop control algorithm, in the antisurge controller, A/S PID 610 , of FIGS. 6 a , 6 b , and 7 . Typical inputs to the antisurge controller 610 are shown in FIGS. 6 a , 6 b , and 7 and comprise a differential pressure signal from a flow transmitter, FT 620 , a suction pressure signal from a suction pressure transmitter, PT1 630 , a discharge pressure signal from a discharge pressure transmitter, PT2 635 , and a rotational speed signal from speed pickup, SE 640 when the driver is variable speed as in FIGS. 6 a , and 7 . Often, in applications using a constant speed driver, such as a constant speed electric motor 645 ,
[0000] as shown in FIG. 6 b , no speed pickup SE 640 in included.
[0032] To emulate the operating point trajectory 520 depicted in FIG. 5 , the antisurge valve 120 is initially fully open, but is ramped closed by the control system as soon as safe operation may be assured. One embodiment of the instant invention is depicted in the flow diagram of FIG. 8 . This embodiment is particularly useful when the startup process is “slow,” taking on the order of several minutes from its initiation. As mentioned, the antisurge valve 120 is set initially at its full open position as shown in block 800 . The full open position may vary between valve types. Generally, full open in the context of this invention is the greatest opening the antisurge valve 120 will realize in its duty in the specific application. The present invention does not depend on the percent opening value at which the antisurge valve 120 is considered in its full open position.
[0033] When the antisurge valve 120 is assured fully open, startup can be initiated as shown in block 805 . At startup, the rotational speed of the compressor 100 is increased according to the guidelines and restrictions of the compressor 100 and driver 110 , 710 manufacturers and the needs of the equipment owner. In particular, critical speeds, if any, are considered and the startup schedule takes these speeds into consideration. Speed increase is depicted in block 810 , and is effected, as shown in FIG. 11 , by increasing a compressor speed set point used by a Variable Frequency Drive (VFD) controller 650 ( FIG. 6 a ) or a rotational speed controller 720 ( FIG. 7 ).
[0034] As the compressor speed increases, the control system 610 repeatedly checks the signals received from the flow transmitter 620 , suction pressure transmitter 630 , and discharge pressure transmitter 635 . The signal values are compared to threshold values, Δp o,min , p s,min , and p d,min , respectively in comparator blocks 815 , 820 , 825 . If the signal magnitude of one or more of the input signals, Δp o , p s , and p d , is not at least as great as its respective threshold value, the rotational speed of the compressor 100 continues to be ramped up as indicated in block 810 .
[0035] Once all three signals, Δp o,min , p s,min , and p d,min , exceed their threshold values Δp o,min , p s,min , and p d,min , two operations are carried out essentially simultaneously and repeatedly. Each of these operations emanates from and returns to the branch block 830 . In one of these operations, the antisurge controller 610 compares the compressor's operating point to the surge control line 510 to determine how the antisurge valve 120 must be manipulated for antisurge protection. If the compressor's operating point is to the right of the surge control line 510 as determined in the comparator block 835 , the antisurge valve 120 is ramped toward its closed position according to a predetermined schedule as shown in block 850 . If the operating point is on or to the left of the surge control line 510 , the antisurge controller 610 manipulates the antisurge valve's 120 position to keep the compressor 100 safe from surge as shown in block 845 .
[0036] The other essentially simultaneous operation involves continuing to increase the compressor's rotational speed according to block 855 until the minimum operating speed, N min , or some predetermined value of speed is reached. Continuing to increase the compressor's rotational speed is effected as explained with regard to block 810 : the rotational speed set point used by the VFD controller 650 or the speed controller 720 is increased with time. Those of ordinary skill in this art are intimate with this aspect of startup control. When the comparator block 840 determines the compressor 100 has reached its minimum operating speed, the control system is shifted from its startup mode to its RUN mode, as shown in block 860 . At that point, the capacity or performance control system takes over varying the compressor speed according to the needs of the process. Note that the minimum operating speed, N min , in comparator block 840 may be the compressor's operating speed if the compressor 120 is to be operated at a constant speed.
[0037] An additional embodiment is shown in FIG. 9 . This embodiment is particularly useful for compressors 120 that may be started rapidly—in less than a minute, for instance. The antisurge valve 120 is set initially at its full open position as shown in block 800 . In block 910 , a timer is reset to zero.
[0038] When the antisurge valve 120 is assured fully open and the timer has been initialized, startup can be initiated as shown in block 805 . At startup, the rotational speed of the compressor 100 is ramped up according to the guidelines and restrictions of the compressor 100 and driver 110 , 710 manufacturers and the needs of the equipment owner. Speed rampup is carried out by increasing the VFD controller's 650 or rotational speed controller's 720 set point, and is depicted in block 810 .
[0039] In this embodiment of the invention, the antisurge valve is ramped toward a closed position after a predetermined time elapses. In comparator block 920 , the time as reported by the timer is compared to the time threshold, t PD . If the time does not exceed the threshold time, the speed continues to increase, but no change to the position of the antisurge valve 120 is made. When the threshold time, t PD , has elapsed, two operations are carried out essentially simultaneously and repeatedly. Each of these operations emanates from and returns to the branch block 830 . In one of these operations, the antisurge controller 610 compares the compressor's operating point to the surge control line 510 to determine how the antisurge valve 120 must be manipulated for antisurge protection. If the compressor's operating point is to the right of the surge control line 510 as determined in the comparator block 835 , the antisurge valve 120 is ramped toward its closed position according to a predetermined ramp rate as shown in block 850 . If the operating point is on or to the left of the surge control line 510 , the antisurge controller 610 manipulates the antisurge valve's 120 position to keep the compressor 100 safe from surge as shown in block 845 .
[0040] The other essentially simultaneous operation involves continuing to increase the compressor's rotational speed according to block 855 until the minimum operating speed, N min , or some predetermined value of speed is reached. When the comparator block 840 determines the compressor 120 has reached its minimum operating speed, the control system is shifted from its startup mode to its RUN mode, as shown in block 860 . At that point, the capacity or performance control system takes over varying the compressor speed according to the needs of the process. Note that the minimum operating speed, N min , in comparator block 840 may be the compressor's operating speed if the compressor 120 is to be operated at a constant speed.
[0041] In FIG. 10 , a third embodiment is illustrated, differing from the embodiment of FIG. 9 in that the driver of FIG. 10 is a constant speed driver, such as a constant speed electric motor 640 ( FIG. 6 b ). In this embodiment, the process of accelerating the driver up to its operating speed, N op , does not incorporate a decision to continue accelerating the driver inasmuch as the driver will continue to accelerate until its operating speed, N op , is reached or it is tripped. Therefore, block 1055 indicates only that the rotational speed continues to rise. Block 1040 is intended only to indicate the compressor rotational speed will increase until the operating speed, N op , is reached, and not that a decision is being made in this comparator block. Ultimately, when the compressor has reached its operating speed, N op , the control system reverts to a RUN mode 860 wherein performance or capacity control is carried out to satisfy process constraints. Note that, in this case especially, the predetermined time lapse, t PD , in comparator block 920 may be zero so the antisurge valve 120 begins to close immediately as startup begins.
[0042] The last two embodiments differ from the prior art in that, in the instant invention, time is used to determine when the antisurge valve 120 is ramped toward its closed position, rather than rotational speed.
[0043] The flow diagrams in FIGS. 8 , 9 and 10 may be considered contents of a logic unit within a compressor control system, such as the antisurge controller 610 depicted in FIGS. 6 a , 6 b , and 7 .
[0044] More detail of the startup initiation block 810 is shown in FIG. 11 . A check to ascertain the antisurge valve 120 is fully open is first carried out in query block 1110 . If the antisurge valve 120 is not fully open, the flow moves to a valve open function 1120 . Once the antisurge valve 120 is fully open, the turbocompressor rotational speed is increased from an initial, zero value as shown in block 1130 .
[0045] The above embodiments are the preferred embodiments, but this invention is not limited thereto. It is, therefore, apparent that many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
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A control method and apparatus for startup of turbocompressors to avoid overpowering a driver of the turbocompressor. In a first embodiment, the control system monitors input signals from transmitters of various control inputs. When the input signals exceed threshold values, the control system begins to close the antisurge valve. In a second embodiment, the antisurge valve begins to close after a predetermined time measured from the time startup is initiated. In both embodiments, the antisurge valve continues to ramp closed until the compressor has reached its operating zone, or until the compressor's operating point reaches a surge control line, at which point the antisurge valve is manipulated to keep the compressor from surging.
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This application claims the Paris convention priority of Japanese patent application 2000 277260 filed on Sep. 12, 2000, the entire disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
i) Field of the Invention
The present invention relates to a phase shift mask blank which is suitable particularly for ArF or F 2 excimer laser, and a manufacturing apparatus and method of the phase shift mask blank.
ii) Description of the Related Art
In recent years, it has been clarified that high resolution and focus depth are two important properties required for photolithography but are in a contradictory relation with each other, and that a practical resolution cannot be enhanced only by high NA and short wavelength of a lens of an exposure apparatus (Monthly Semiconductor World 1990.12, Applied Physics Vol. 60, Nov. 1991, and the like).
Under such situation, phase shift lithography has been noted as the next-generation photolithography technique, and partially brought to practical use. The phase shift lithography is a method for enhancing the resolution of photolithography by change only of a mask without changing an optical system. When a phase difference is applied between exposure lights transmitted through the photo mask, mutual interference of the transmitted lights can be utilized to rapidly enhance the resolution.
The phase shift mask is a mask for using light strength information together with phase information. Various types of the masks are known such as Levenson type, auxiliary pattern type, and self-matching type (edge emphasizing type). These phase shift masks have a complicated constitution and require a high degree of manufacturing technique as compared with the conventional photo mask which has only the light strength information.
In recent years, a so-called halftone type phase shift mask has been developed as one of the phase shift masks.
In the halftone phase shift mask, a light semi-transmission portion has two functions: a shield function of substantially shielding the exposure light; and a phase shift function of shifting (usually reversing) a light phase. Therefore, it is unnecessary to separately form a shield film pattern and phase shift film pattern. This type of phase shift mask is simple in constitution and easy in manufacturing.
For the halftone phase shift mask, as shown in FIG. 4, a mask pattern formed on a transparent substrate 100 is constituted of a light transmission portion (transparent substrate exposed portion) 200 for transmitting a light which is strong enough to substantially contribute to exposure, and a light semi-transmission portion (shield and phase shifter portion) 300 for transmitting a light which is not strong enough to substantially contribute to the exposure (FIG. 4 A). Additionally, the phase of the light transmitted to the light semi-transmission portion is shifted, and the light semi-transmission portion is brought to a substantially reversed relation with respect to the phase of the light transmitted through the light transmission portion (FIG. 4 B). The lights transmitted in the vicinity of a boundary between the light semi-transmission portion and the light transmission portion and turned to the opposite portions by diffraction phenomenon cancel each other. Thereby, light strength in the boundary is substantially set to zero, and contrast, that is, resolution of the boundary is enhanced (FIG. 4 C).
The light semi-transmission portion (phase shift layer) in the halftone phase shift mask or blank needs to have a required optimum value with respect to both transmittance and phase shift amount. Concretely, (1) the transmittance in an exposure wavelength of KrF, ArF, or F 2 excimer laser, or the like can be adjusted in a range of 3 to 20%, (2) a phase angle can be adjusted usually to a value in the vicinity of 180° in the exposure wavelength, and (3) the transmittance needs to be usually testable in a range of 65% or less in test wavelengths such as 257 nm, 266 nm, 364 nm, and 488 nm.
In recent years, there has been a demand for a finer processing of a device, or the like, and shortening of an exposure wavelength for use in the device has been advanced. On the other hand, influences of a particle adhering to the mask blank and a pinhole formed in the mask have been increasingly regarded as problems. That is, for example, by generation of arc in a film formation apparatus during film formation, or other causes, a particle with a particle diameter of about one micron or less is sometimes mixed in the light semi-transmission film at a ratio of about 0.05 to 0.5 particle per one square centimeter. Moreover, when there is a fine groove or hole in the surface of a target, the particle with a particle diameter of about several microns or less is sometimes mixed in the light semi-transmission film. When the particle mixed in the light semi-transmission film falls out in a cleaning process, the pinhole is generated. Therefore, in order to prepare the mask blanks having less pinholes, it is necessary to reduce the number of particles during formation of the light semi-transmission film.
Additionally, in conventional mask blanks for i-ray, or KrF excimer laser, in which a relatively long wavelength is used as the exposure wavelength, there are many particles or pinholes. Therefore, the blanks cannot be applied to some of photo mask blanks for KrF, in which a pattern finer than a conventional pattern is formed, or mask blanks for a short wavelength of ArF or F 2 excimer laser.
With the shortening of the exposure wavelength, a property of the particle or the pinhole, required for the mask blanks, becomes stricter. It is necessary for practical use of the mask blanks for the short wavelength of the ArF or F 2 excimer laser to reduce the number of particles or pinholes having a diameter larger in size than about a half of the exposure wavelength as much as possible.
SUMMARY OF THE INVENTION
The present invention has been developed under the aforementioned background, and a first object thereof is to provide a phase shift mask blank in which the number of particles or pinholes each having a diameter larger than a diameter substantially equivalent in size to an exposure wavelength is reduced as much as possible.
Moreover, a second object of the present invention is to provide a manufacturing apparatus and method able to manufacture the phase shift mask blank in which the number of particles or pinholes each having the diameter larger than the diameter equivalent in size to the exposure wavelength is reduced as much as possible.
Furthermore, a third object of the present invention is to provide a photo mask blank in which the number of particles or pinholes is reduced as much as possible.
Additionally, a fourth object of the present invention is to provide a manufacturing apparatus and method which can manufacture the photo mask blank having the number of particles or pinholes reduced as much as possible.
To achieve the aforementioned objects, the present invention has the following constitutions.
(Constitution 1) A manufacturing method of a photo mask blank having a thin film for forming a pattern on a transparent substrate,
wherein during sputtering formation of the thin film, the surface of a target is directed downwards and the surface of a substrate is directed upwards with respect to a gravity direction, and a peripheral edge of the substrate is shielded in order to prevent film formation.
Particularly, a manufacturing method of a halftone phase shift mask blank having a light semi-transmission film on a transparent substrate,
wherein during sputtering formation of the light semi-transmission film, the surface of a target is directed downwards and the surface of a substrate is directed upwards with respect to a gravity direction, and a peripheral edge of the substrate is shielded in order to prevent film formation.
(Constitution 2) A manufacturing method of a photo mask blank having a thin film for forming a pattern on a transparent substrate, comprising a step of:
manufacturing the thin film using a DC magnetron sputtering apparatus comprising at least a sputtering target, a magnetron cathode with the target attached thereto, a substrate holder disposed opposite to the target, and a shield disposed on an inner wall of a vacuum tank inside the vacuum tank,
wherein the surface of a target is directed downwards with respect to a gravity direction, and
the apparatus has a mechanism for reducing film formation on a non-sputtered area on the target and the surface of the shield.
(Constitution 3) The manufacturing method according to constitution 2 wherein the mechanism for reducing the film formation onto the non-sputtered area on the target comprises a mechanism in which a whole-surface erosion cathode is used as the magnetron cathode, a mechanism for shielding the non-sputtered area on the target, or a mechanism for roughening the surface of a non-sputtered portion on the target.
(Constitution 4) The manufacturing method according to constitution 3 wherein the mechanism for reducing the film formation onto the non-sputtered area on the target further comprises a mechanism for forming a corner in the target into a curved surface, and roughening an end surface of the target.
(Constitution 5) The manufacturing method according to constitution 2 wherein in the mechanism for reducing the film formation on the shield surface, the shield is kept at a constant temperature, and a shape of the shield is designed so that a relative film formation speed t in the following equation (i) in at least a shield position in the vicinity of the target is prevented from being larger than a value in a position on the substrate:
t= cos θ 1 ×Sin (θ 1 −θ 2 )/ r 2 (i)
(in the equation (i), r denotes a distance between a target center and a shield position, θ 1 denotes an angle of a line connecting the target center to the shield position with respect to a normal of a target plane, θ 2 denotes an angle of a shield plane with respect to the normal of the target plane, and t denotes the relative film formation speed in the shield position defined by r and θ 1 ).
(Constitution 6) The manufacturing method according to constitution 5 wherein in the mechanism for reducing the film formation onto the shield surface comprises a mechanism for forming a corner in the shield into a curved surface, roughening the surface of the shield, and disposing an earth shield above the target plane.
(Constitution 7) The manufacturing method according to any one of constitutions 2 to 6 wherein the apparatus further comprises a backing plate to which the target is to be attached, and the surface of the backing plate is roughened.
(Constitution 8) The manufacturing method according to any one of constitutions 2 to 7 wherein the apparatus further comprises a shield plate for preventing the film from being formed on a peripheral portion of the substrate.
(Constitution 9) A photo mask blank manufactured using the manufacturing method according to any one of constitutions 1 to 8.
(Constitution 10) A photo mask blank having a thin film for forming a pattern on a transparent substrate,
wherein a total number of particles and pinholes having a diameter larger than a diameter substantially equivalent in size to an exposure wavelength for use in the blank as a mask is 0.1 or less per square centimeter.
(Constitution 11) A photo mask blank having a thin film for forming a pattern on a transparent substrate,
wherein an exposure wavelength for use in the blank as a mask has a center wavelength of 193 nm or less, and a total number of particles and pinholes having a diameter larger than 0.2 μm is 0.1 or less per square centimeter.
(Constitution 12) The photo mask blank according to constitution 10 or 11 wherein the thin film for forming the pattern is a light semi-transmission film, and the photo mask blank is a halftone phase shift mask blank.
(Constitution 13) A manufacturing apparatus of a photo mask blank for carrying out the manufacturing method according to any one of constitutions 1 to 8.
(Constitution 14) A photo mask manufactured by patterning a thin film in the photo mask blank according to any one of constitutions 9 to 12.
(Constitution 15) A pattern transfer method using the photo mask according to constitution 14 to transfer a pattern.
In the constitution 1, when the target plane is directed downwards with respect to the gravity direction, the substrate surface necessarily turns upwards, and the film is formed on the whole surface and side surface of the substrate, but the peripheral edge of the substrate is shielded to prevent the film formation as in the constitution 1. Thereby, particles generated when the film is stripped by handling or cleaning after forming the light semi-transmission film can remarkably be reduced, and yield of the mask is remarkably enhanced. This is necessary particularly for the phase shift mask for the short wavelength of ArF or F 2 excimer laser.
According to the constitutions 2 to 6, the generation of the particles from the target plane, shield plane (including the earth shield), or a gap between the target and the earth shield can securely be prevented. Additionally, respective countermeasures according to the constitutions 2 to 6 are effective alone. However, a combination of all the countermeasures can securely prevent the generation of the particles from the target plane, the shield plane (including the earth shield) or the gap between the target and the earth shield.
According to the constitution 7, the generation of the particles from a backing plate portion can securely be prevented.
According to the constitution 8, when the peripheral edge of the substrate is shielded by the shield plate in order to prevent the film from being formed on the peripheral edge of the substrate, the particles generated by the film stripped by handling or cleaning after forming the light semi-transmission film can remarkably be reduced, and the yield of the mask is remarkably enhanced. This is necessary particularly for the phase shift mask for the short wavelength of ArF or F 2 excimer laser.
According to the constitution 9, the photo mask blank having few defects can be obtained.
According to the constitution 10, the total number of particles and pinholes having the diameter larger than the diameter substantially equivalent in size to the exposure wavelength for use in the blank as the mask is 0.1 or less per square centimeter. Therefore, practical use of the photo mask for the short wavelength of ArF or F 2 excimer laser can be realized. When the number exceeds 0.1, it is difficult to realize the practical use of the photo mask for the short wavelength of the ArF or F 2 excimer laser.
Additionally, even in the present situation, the mask can practically be used for KrF excimer laser, but the number of particles and pinholes is further preferably reduced. Therefore, the invention of the constitution 10 can be applied to the photo mask blank for KrF excimer laser, or particularly to some of the photo mask blanks for KrF in which a pattern finer than the conventional pattern is formed. Moreover, the invention can also be applied to a general photo mask blank, because it is preferable to further reduce the number of particles or pinholes.
Here, the substantially equivalent wavelength includes wavelength ±20%.
Additionally, the total number of particles and pinholes having a diameter larger in size than about a half of the exposure wavelength is preferably 0.1 or less per square centimeter. This range includes ½ wavelength ±20%.
According to the constitution 11, the exposure wavelength for use in the blank as the mask has a center wavelength of 193 nm or less, and the total number of particles and pinholes having a diameter larger than 0.2 μm is 0.1 or less per square centimeter. Therefore, the practical use of the photo mask for the short wavelength of the ArF or F 2 excimer laser can be realized. Additionally, the total number of particles and pinholes having a diameter larger than 0.15 μm, preferably larger than 0.1 μm is preferably 0.1 or less per square centimeter. This is realized depending upon a limitation of sensitivity of a defect test apparatus. In order to detect the particles and pinholes having smaller diameters, the defect test apparatus with a higher sensitivity is necessary.
According to the constitution 12, the practical use of the halftone phase shift mask for some of KrF excimer lasers in which the pattern finer than the conventional pattern is formed and for the short wavelength of the ArF or F 2 excimer laser can be realized.
According to the constitution 13, it is possible to manufacture the photo mask blank having few defects.
According to the constitution 14, the photo mask having few defects can be obtained, and the practical use of the photo mask for some of KrF excimer lasers in which the pattern finer than the conventional pattern is formed and for the short wavelength of the ArF or F 2 excimer laser can be realized.
According to the constitution 15, the photo mask having few defects, and the short exposure wavelength of the KrF excimer laser or ArF or F 2 excimer laser can be used to realize a fine pattern processing.
The present invention will be described hereinafter in detail.
In order to achieve the aforementioned objects, as a result of pursuing of researches, the following has been found.
Mixture of the particles into the light semi-transmission film during sputtering causes stripping of the film attached in a vacuum tank. The particles caused by the stripped film are generated from a non-sputtered portion of the target surface, a gap between the target and an electrically grounded vacuum tank inner wall (earth shield), a film attachment preventing component (shield) detachably attached to the inner wall of the vacuum tank, and the like.
In order to prevent the particles from being generated from the non-sputtered portion of the target surface, the following countermeasures are effective: (countermeasure 1) a whole-surface erosion cathode or the like is used to reduce an area of the non-sputtered portion on the target; (countermeasure 2) the non-sputtered portion (non-erosion portion) of the target surface is shielded by a shield member; and (countermeasure 3) the non-sputtered portion (non-erosion portion) of the target surface is roughened by blast treatment (treatment for mechanically/physically roughening the surface).
The present invention will be described hereinafter with reference to FIGS. 1 and 2, but these are drawings for simple description of positions to be subjected to the countermeasures, and the apparatus of the present invention is not limited to forms (e.g., shapes and positional relation (distance) of the respective portions) of these drawings.
The generation of the particle from a gap 13 between a target 5 and an earth shield 12 raises a problem, when the whole-surface erosion cathode is used and the end of the target is not shielded with a shield member or the like. In order to prevent the particle from being generated from this gap, the following countermeasures are effective: (countermeasure 4) a portion of a corner 5 a in the end of the target is formed into a curved surface (R processed); (countermeasure 5) the blast treatment or another method is used to roughen a target end 5 b ; (countermeasure 6) the blast treatment or another method is used to roughen exposed backing plate surfaces 4 a , 4 b ; (countermeasure 7) a corner 12 a of the earth shield is R-processed; (countermeasure 8) the surface of the earth shield 12 is roughened by the blast treatment or another method; and (countermeasure 9) the earth shield 12 is disposed above a target plane d (on a side of the backing plate 4 ).
In order to prevent the particle from being generated from the shield portion, (countermeasure 10) improvement of a shield shape is effective as described later.
A formation speed t of the film attached to the shield disposed in the vacuum tank can qualitatively be represented by the equation (i) developed by the present inventor.
t= cos θ 1 ×sin (θ 1−θ 2 )/r 2 (i)
Here, respective variables in the equation (i) will be described with reference to FIG. 1 . Variable r denotes a distance between a target center a and a shield position c, θ 1 denotes an angle of a line connecting the target center a to the shield position c with respect to a normal e of the target plane, θ 2 denotes an angle of a shield plane 11 with respect to the normal e of the target plane, and t denotes the relative film formation speed in the shield position c defined by r and θ 1 . Additionally, the shield 11 has a leaf shape in FIG. 1, but the shield 11 may have the leaf shape or a block shape. Moreover, the shield 11 is electrically insulated from the earth shield 12 , the earth shield 12 may be earthed, and a voltage may be applied to the shield 11 .
In the shield position c in the vicinity of the target 5 (area in which a value of r is smaller than a distance to the transparent substrate with the light semi-transmission film to be formed thereon), it is effective for prevention of the particle generation to design the shape of the shield 11 so that the relative film formation speed t in the equation (i) is prevented from being larger than the value in the position on the substrate. In order to satisfy the aforementioned conditions, it is necessary to set a sufficient distance (set r to be large) between the shield position c to which many films are attached (θ 1 is small) and the target 5 (i.e., the shield 11 in the vicinity of the target is disposed apart from the target). It is also necessary to reduce an angle θ 3 of the shield plane in the shield position in the vicinity of the target 5 (with small r) with respect to the target plane d (set θ 2 to be large and close to θ 1 ) (i.e., set the shield plane in the vicinity of the target to be horizontal with the target plane d).
In order to prevent the particle from being generated from the shield portion, (countermeasure 11) to remove (R process) a sharp corner or a sharp screw from a portion to which the film is attached on the shield, and (countermeasure 12) to roughen the surface of the shield by the blast treatment or the like are effective.
Additionally, (countermeasure 13) to hold the shield to which the film is attached by heating at a constant temperature is also effective as means for reducing the particle generated from the shield.
Here, the shield (including the earth shield) in the vicinity of the target is heated by a plasma generated on the target or a sputtered particle from the target. When film formation start and end are repeated, temperature on the shield changes, and stress of the film attached to the shield changes with a temperature change. When the film stress on the shield changes, the film is cracked or stripped, and therefore the particle is mixed into the light semi-transmission film. When the shield is held at constant temperature, the stress of the film is also kept to be constant, and the particles generated from the shield decrease. Optimum temperature of the shield changes with the material of the shield or the type of the film. However, in the present invention, when temperature of the shield is controlled to 160° C. from 100° C., the number of particles mixed in the light semi-transmission film can be reduced.
When the target surface is directed upwards, the particle adheres to the target surface, this causes abnormal electric discharge, a micro groove and hole are formed in the target surface by the abnormal electric discharge and the abnormal electric discharge is repeated. The film attached to the particle adhering to target surface or the fine groove or hole is heated by the plasma in the vicinity of the target, evaporation and burst are caused, and the particle or impurity is mixed in the light semi-transmission film. On the other hand, when the target surface is directed downwards, the particle does not easily adhere to the target surface, and therefore the abnormal electric discharge does not easily occur. Therefore, in order to form the light semi-transmission film having few particles, a sputter down system in which the target surface is directed downwards is preferable.
Additionally, the particle is sometimes generated by film stripping caused by handling or cleaning after formation of the light semi-transmission film. To prevent this, as shown in FIG. 2, there is (countermeasure 15) a method of disposing the shield plate for shielding a portion 6 a for holding a transparent substrate 6 before and after the film formation, and forming no light semi-transmission film on this portion.
Additionally, during attaching of the substrate to the substrate holder, the shield plate can preferably be retreated to a position in which the attaching of the substrate is not inhibited. Moreover, the shield plate is preferably movable so that a clearance between the surface of the substrate with the film formed thereon and the shield plate can be adjusted with high precision (e.g., precision of about 0.1 mm) after attaching the substrate to the substrate holder.
The countermeasures for preventing the particle from being generated in the sputtering apparatus for forming the light semi-transmission film have mainly been described above. However, (countermeasure 16) to automate handling until introducing of the transparent substrate into the sputtering apparatus with a mechanism having little particle generation, or to set an atmosphere of a substrate introduction portion to be in a dust-free state is essential for preventing the particle generation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a main part showing a countermeasure portion of the present invention in a DC magnetron sputtering apparatus.
FIG. 2 is a schematic diagram of a main part showing the countermeasure portion of the present invention in the DC magnetron sputtering apparatus.
FIG. 3 is a schematic diagram of the DC magnetron sputtering apparatus for use in an embodiment.
FIG. 4 is an explanatory view of transfer principle of a halftone phase shift mask.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Examples of the present invention will be described hereinafter in further detail.
A DC magnetron sputtering apparatus shown in FIG. 3 was used, a combination of particle countermeasures shown in Table 1 is changed as shown in Table 2, and halftone phase shift mask blanks for ArF excimer laser (193 nm) were prepared.
Concretely, a mixed target (Mo:Si=8:92 mol %) of molybdenum (Mo) and silicon (Si) was used to form a nitrided thin film (film thickness of about 670 angstroms) of molybdenum and silicon (MoSiN) on a transparent substrate by reactive sputtering (DC sputtering) in a mixed gas atmosphere (Ar:N 2 =10%:90%, pressure: 0.1 Pa) of argon (Ar) and nitrogen (N 2 ). In this manner, the phase shift mask blank (film composition: Mo:Si:N=7:45:48) for ArF excimer laser (wavelength of 193 nm) was obtained.
Here, the DC magnetron sputtering apparatus shown in FIG. 3 has a vacuum tank 1 . A magnetron cathode 2 and substrate holder 3 are disposed in the vacuum tank 1 . The sputtering target 5 bonded to the backing plate 4 is attached to the magnetron cathode 2 . In the example, oxygen-free steel is used in the backing plate 4 , and indium is used to bond the sputtering target 5 to the backing plate 4 . The backing plate 4 is directly or indirectly cooled by a water cooling mechanism. The magnetron cathode 2 , backing plate 4 and sputtering target 5 are electrically connected to one another. The transparent substrate 6 is attached to the substrate holder 3 .
The vacuum tank 1 is evacuated by a vacuum pump via an exhaust port 7 . An atmosphere in the vacuum tank reaches a degree of vacuum which does not influence a property of the formed film, a mixed gas containing nitrogen is then introduced via a gas introduction port 8 , a DC power supply 9 is used to apply a negative voltage to the magnetron cathode 2 , and sputtering is performed. The DC power supply 9 has an arc detecting function, and can monitor an electric discharge state during sputtering. A pressure inside the vacuum tank 1 is measured by a pressure gauge 10 .
A transmittance of a light semi-transmission film formed on the transparent substrate is adjusted by a type and mixture ratio of gases introduced via the gas introduction port 8 . When the mixed gas contains argon and nitrogen, the transmittance is increased by increasing a ratio of nitrogen. When a desired transmittance cannot be obtained by adjusting the ratio of nitrogen, oxygen is added to the mixed gas containing nitrogen, and the transmittance can further be increased.
A phase angle of the light semi-transmission film was adjusted by a sputtering time, and the phase angle in an exposure wavelength was adjusted to about 180°.
In the example, as shown in FIG. 2, a range of about 2 mm from the end of a film formed surface of the transparent substrate 6 disposed opposite to the sputtering target 5 is covered with a shield plate 14 , so that a light semi-transmission film 20 is prevented from being formed on the holding portion 6 a . Additionally, the holding portion 6 a in FIG. 2 is crosshatched to show the portion, but naturally the light semi-transmission film is not formed on the holding portion 6 a.
Evaluation
A defect test apparatus (manufactured by KLA-Teucor Co.: KT-353UV) was used to check numbers of particles and pinholes with diameters of 0.2 μm or more after the film formation, and numbers of particles and pinholes with diameters of 0.2 μm or more after the cleaning with respect to an area of 174.2 cm 2 in the phase shift mask blanks (size: 152 mm square) obtained as described above. Results are shown in Table 2.
TABLE 1
Countermeasure
No.
Particle countermeasure
1
Use whole-surface erosion cathode
2
Mask non-erosion portion
3
Blast treatment of non-erosion portion
4
R-process target end
5
Blast treatment of target end surface
6
Blast treatment of backing plate
7
R-process earth shield
8
Blast treatment of earth shield
9
Improve earth shield plane position
10
Improve shield shape
11
R-process shield surface, remove screw
12
Blast treatment of shield surface
13
Shield temperature control
14
Sputter down system
15
Shield substrate periphery
16
Automate substrate introduction, bring introduction
portion to dust-free state
TABLE 2
Effect of particle countermeasure
After film formation
After cleaning
Particles
Pinholes
Particles
Pinholes
(0.2 μm
(0.2 μm
(0.2 μm
(0.2 μm
Countermeasure No.
or more)
or more)
or more)
or more)
8, 12, 14
6311
many
3304
many
8, 12, 14, 13
2836
many
1329
many
8, 12, 14, 13, 1
1029
many
448
many
8, 12, 14, 13, 2, 3
1144
many
456
many
8, 12, 14, 13, 1, 7
582
many
224
many
11
8, 12, 14, 13, 1, 7
152
12
48
29
11, 9, 10
8, 12, 14, 13, 1, 7
72
8
21
12
11, 9, 10, 4, 5, 6
8, 12, 14, 13, 1, 7
65
2
13
7
11, 9, 10, 4, 5, 6, 15
all excluding
24
0
5
3
2, 3
Measurement area: 174.2 cm 2
As seen from Table 2, with use of the apparatus in which the sputter down system (countermeasure 14), countermeasures 8, 12, 14, 13, 7, 11, 9, 10 as a mechanism for reducing the film formation onto the shield surface, and countermeasure 1 as a mechanism for reducing the film formation to a non-sputtered area on the target are taken, the numbers of particles and pinholes after cleaning are in two digits, and are rapidly reduced. Additionally, the countermeasures 10 and 13 are very effective in the mechanism for reducing the film formation onto the shield surface. Moreover, when the countermeasures 4, 5, 6 are added to the aforementioned countermeasures, the number of defects is further reduced. Furthermore, when the countermeasure 15 is further taken, the number of defects is further reduced. The countermeasure 15 for shielding the substrate periphery is very effective, because the defect can be prevented from being generated during handling of the substrate.
Moreover, with all the countermeasures (1, 4 to 16) excluding the countermeasures 2, 3, the halftone phase shift mask blank can be obtained in which the total number of particles and pinholes each having a diameter (0.2 μm or more) larger than the diameter substantially equivalent in size to the exposure wavelength (193 nm) is preferably 0.1 or less per square centimeter.
Moreover, it is seen that the individual countermeasures are effective, because the number of particles or pinholes decreases.
Additionally, in the conventional mask blanks for i-ray, or KrF excimer laser, in which the target surface is directed upwards and the film is formed in an in-line type sputtering apparatus, there are many particles or pinholes. Therefore, it has been confirmed that these blanks cannot be applied to the mask blanks for the short wavelength of the ArF or F 2 excimer laser.
The preferred examples of the present invention have been described above, but the present invention is not limited to the aforementioned examples.
For example, the method and apparatus of the present invention are applied to the halftone phase shift mask blanks having the light semi-transmission film in the aforementioned embodiment, but the present invention is not limited to the embodiment. For example, the method and apparatus of the present invention may be applied to the photo mask blank which has a shield film formed of chromium or a chromium compound.
Additionally, molybdenum was used as a metal constituting the light semi-transmission film, but this is not limited, and zirconium, titanium, vanadium, niobium, tantalum, tungsten, nickel, palladium, and the like can be used.
Moreover, the target of molybdenum and silicon was used as the target containing metal and silicon, but this is not limited. In the target containing metal and silicon, molybdenum is particularly superior among the aforementioned metals in controllability of the transmittance and in that a target density increases and particles in the film can be reduced with use of the sputtering target containing metal and silicon. Titanium, vanadium, and niobium are superior in resistance to an alkaline solution, but slightly inferior to molybdenum in the target density. Tantalum is superior in the resistance to the alkaline solution and target density, but slightly inferior to molybdenum in the controllability of transmittance. Tungsten has properties similar to those of molybdenum, but is slightly inferior to molybdenum in an electric discharge property during sputtering. Nickel and palladium are superior in the optical property and resistance to the alkaline solution, but dry etching is slightly difficult to perform. Zirconium is superior in the resistance to the alkaline solution, but inferior to molybdenum in the target density, and the dry etching is slightly difficult to perform. Considering these, molybdenum is most preferable at present. Molybdenum is also preferable for a nitrided molybdenum and silicon (MoSiN) thin film (light semi-transmission film) in superior chemicals resistance such as acid resistance and alkali resistance.
Furthermore, in order to obtain the thin film of a composition in which electric discharge stability is secured during film formation and various properties of the phase shift mask are satisfied, the target containing 70 to 95 mol % of silicon, and metal is preferably subjected to DC magnetron sputtering in the atmosphere containing nitrogen. Thereby, the light semi-transmission film containing nitrogen, metal and silicon is preferably formed.
When the content of silicon in the target is larger than 95 mol %, a voltage is not easily applied (electricity is not easily passed) to a target surface (erosion portion) in the DC sputtering, and the electric discharge becomes unstable. Moreover, when the content of silicon is less than 70 mol %, the film constituting a light semi-transmission portion with a high transmittance cannot be obtained. Furthermore, electric discharge stability is further enhanced by combination of the nitrogen gas with the DC sputtering.
Additionally, the electric discharge stability during film formation also influences film quality. When the electric discharge stability is superior, the light semi-transmission film with a satisfactory film quality is obtained.
Furthermore, in the manufacturing apparatus and method of the present invention, there can be provided a constitution in which the transparent substrate is disposed opposite to the target with a certain angle, the substrate is rotated, and the film is formed by inclined sputtering.
As described above, according to the phase shift mask blank of the present invention, the total number of particles and pinholes each having a diameter (particularly larger than 0.2 μm) larger than the diameter substantially equivalent in size to the exposure wavelength in the light semi-transmission film is preferably 0.1 or less per square centimeter. Therefore, the practical use of the phase shift mask for the short wavelength of the ArF or F 2 excimer laser can be realized.
Moreover, according to the manufacturing apparatus and method of the phase shift mask blank of the present invention, it is possible to manufacture the phase shift mask blank in which the total number of particles and pinholes each having a diameter (particularly larger than 0.2 μm) larger than the diameter substantially equivalent in size to the exposure wavelength in the light semi-transmission film is preferably 0.1 or less per square centimeter.
Furthermore, according to the present invention, there can be provided the photo mask blank in which the number of particles or pinholes is reduced as much as possible.
Additionally, there can be provided the manufacturing apparatus and method able to manufacture the photo mask blank in which the number of particles or pinholes is reduced as much as possible.
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There is provided a manufacturing apparatus and method able to manufacture a phase shift mask blank in which a total number of particles and pinholes having a diameter larger than about a half of an exposure wavelength in a light semi-transmission film is 0.1 or less per square centimeter. In a DC magnetron sputtering apparatus for manufacturing a halftone phase shift mask blank, for example, a target plane is disposed downwards with respect to a gravity direction, a whole-surface erosion cathode is used, a corner portion 5 a of an end of a target and a corner portion of an earth shield are chamfered (R processed), a target end 5 b , an exposed backing plate surface 4 b and the surface of an earth shield 12 are roughened, and the earth shield 12 is disposed above a target plane d (on a backing plate side).
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a detergent container of a washing machine, more particularly, which is capable of supplying powdered detergent mixed with water to a tub without suspending, by preventing a drain passage of the detergent container from clogging due to powdered detergent stored in the detergent container.
2. Description of the Related Art
A washing machine is to decontaminate dirt on clothes or bedding (hereinafter referred as “laundry”) contained in a drum. It cleans laundry through washing, rinsing, dehydrating and drying.
FIG. 1 shows a drum-type washing machine having a detergent container based on the prior art, and FIG. 2 shows the detergent container which stores a large quantity of powdered detergent based on the prior art.
The conventional drum-type washing machine comprises a cabinet 2 which defines an outer appearance of the washing machine, a tub 4 mounted in the cabinet 2 , the drum 6 rotatably set in the tub 4 to wash laundry, a plurality of lifters 8 placed in an inner side of the drum 6 , which lifts up laundry to fall from predetermined height by gravity, and a motor (not shown) installed in a rear of the tub 4 to generate power (see FIG. 1 ).
A front cover 10 is mounted on a front of the cabinet 2 , and a door 12 is set on the front cover 10 .
A top plate 14 is placed on a top of the cabinet 2 , and a control panel 11 to manipulate the washing machine is placed between the top plate 14 and the front cover 10 . A water supplier 20 and a detergent supply apparatus 30 are installed in a top side of the cabinet 2 .
The water supplier 20 includes a plurality of water supply valves 24 to control water supplied through an external hose 22 , a plurality of water supply hoses 26 to guide water through the water supply valve 24 to the detergent supply apparatus 30 , and a bellows tube 28 to guide water and detergent through the detergent supply apparatus 30 to the inside of the tub 4 .
The detergent supply apparatus 30 includes a housing 32 connected to the bellows tube 28 , the detergent container 40 inserted into the housing 32 , and a dispenser 34 installed in a top of the housing 32 and connected to the water supply hose 26 to supply water to the detergent container 40 .
After laundry is loaded in the drum 6 and detergent is accommodated in the detergent container 40 , water is supplied by the water supplier 20 . Detergent is mixed in water through the detergent supply apparatus 30 , and is supplied to the tub 4 . As soon as a predetermined quantity of water and detergent is filled in the tub 4 , the drum 6 is rotated to wash, rinse and dehydrate.
The conventional detergent container 40 comprises a powdered detergent chamber 42 which stores powdered detergent, a detergent chamber 46 having an outlet 44 to discharge detergent in the powdered detergent chamber 42 together with water, which is open at its rear, and a subsidiary detergent chamber 48 located in a side of the outlet 44 to store agents, e.g. bleach and fabric softner (see FIG. 2 ).
The subsidiary detergent chamber 48 is parted from a bottom of the detergent chamber 46 by predetermined distance to provide a drain passage 49 of water and detergent between the powdered detergent chamber 42 and the outlet 44 .
When water is supplied to the powdered detergent chamber 42 from the dispenser 34 , powdered detergent with water passes the drain passage 49 , drains to the housing 32 through the outlet 44 , and then gets to the tub 4 through the bellow tube 28 .
In the conventional detergent container of the washing machine, as illustrated in FIG. 2 , when excessive powdered detergent is put in the powdered detergent chamber 42 , even though water is supplied, the powdered detergent comes to clog an entrance of the drain passage 49 , thus water and detergent cannot drain from the detergent container 40 .
As the drain passage 49 gets clogged by detergent and water supply is continued, water mixed with detergent comes to flow over the detergent chamber 42 , and flows to the subsidiary detergent chamber 48 . Then, water flows backward to the dispenser 34 , while a lot of bubbles are arisen.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a detergent container which is capable of preventing a drain passage of the detergent container from clogging due to detergent, besides smoothly supplying water and detergent to a tub.
A detergent container of a washing machine with an aspect of the present invention to fulfill the foregoing needs comprises a powdered detergent chamber to store powdered detergent, an outlet to drain powdered detergent mixed with water contained in the powdered detergent chamber, a subsidiary detergent chamber to store bleach or fabric softner, a drain passage to guide powdered detergent mixed with water from the powdered detergent chamber to the outlet, and a bypass passage to make powdered detergent mixed with water detoured to the drain passage from the powdered detergent chamber.
The bypass passage is formed between the powdered detergent chamber and the subsidiary detergent chamber by a partition member, installed apart from the subsidiary detergent chamber at a regular interval toward the powdered detergent chamber.
The partition member is provided by a partition plate.
The partition plate is separated from a bottom of the detergent container by predetermined distance, and is vertically set in the detergent container. At least one end of the partition plate is fixed to one end of the detergent container.
A top of the partition plate is placed lower than that of the subsidiary detergent chamber and the detergent container. A bottom of the partition plate is placed lower than that of the subsidiary detergent chamber as well.
The powdered detergent chamber is partitioned into a main detergent storing section and a preliminary detergent storing section. The partition plate is installed in at least one, either between the main detergent storing section and the subsidiary detergent chamber or between the preliminary detergent storing section and the subsidiary detergent chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is an exploded perspective view of a drum-type washing machine having a detergent supply apparatus, according to the prior art.
FIG. 2 is a sectional view of a detergent container which stores a large amount of powdered detergent, according to the prior art.
FIG. 3 is an exploded perspective view of the detergent supply apparatus having the detergent container, according to the embodiment of the present invention.
FIG. 4 is a plane view of the detergent container, according to the embodiment of the present invention.
FIG. 5 is a sectional view of the detergent container which stores a small amount of powdered detergent, according to the embodiment of the present invention.
FIG. 6 is a sectional view of the detergent container which stores a large amount of powdered detergent, according to the embodiment of the present invention.
FIG. 7 is a sectional view of the detergent container having a bypass plate, according to the embodiment of the present invention.
FIG. 8 is a sectional view of the detergent container having the bypass plate, according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.
FIG. 3 shows a detergent supply apparatus having a detergent container, according to the embodiment of the present invention. FIG. 4 shows the detergent container, according to the embodiment of the present invention. And, FIGS. 5 and 6 show the detergent container which stores a small/large amount of powdered detergent, according to the embodiment of the present invention.
As shown in FIG. 3 or 5 , the detergent supply apparatus having the detergent container comprises a housing 50 installed in a front of a washing machine and connected to a bellows tube 28 , which is open at its front and top, the detergent container 60 inserted into the housing 50 , and a dispenser 70 mounted in a top of the housing 50 and connected to a water supply hose 26 to dispense water to the detergent container 60 .
An overflow 52 is configured in the housing 50 , where water and detergent from the detergent container 60 is discharged to the bellows tube 28 .
The detergent container 60 comprises a powdered detergent chamber 62 replenished with powdered detergent, a detergent chamber 66 having an outlet 64 which is open at its rear, a subsidiary detergent chamber 68 located a side of the outlet 64 to store bleach or fabric softner, and spaced apart from a bottom of the detergent chamber 66 to provide a drain passage 69 between the powdered detergent chamber 62 and the outlet 64 , and a bypass passage 80 located between the powdered detergent chamber 62 and the subsidiary detergent chamber 68 , not to clog the drain passage 69 by powdered detergent.
A front panel 67 having a handle 67 b is mounted on a front of the detergent chamber 66 , which is open at its rear and top. A ventilation hole 67 c is existed on a bottom of the front panel 67 , so as to inflow external air in the housing 50 .
A partition wall 66 f is formed, dividing the powdered detergent chamber 62 to include a main detergent storing section 62 a and a preliminary detergent storing section 62 b , which is separated from both sidewalls 66 d , 66 e of the detergent chamber 66 by predetermined distance.
The partition wall 66 f also partitions the outlet 64 into a main detergent outlet 64 a connected to the main detergent storing section 62 a , and a preliminary detergent outlet 64 b connected to the preliminary detergent storing section 62 b.
The subsidiary detergent chamber 68 is partitioned into a bleach storing section 68 a in a side of the main detergent outlet 64 a , and a fabric softner storing section 68 b in a side of the preliminary detergent outlet 64 b.
The bleach storing section 68 a has a siphon 90 protruded and a siphon cover 91 which provides a water drain passage with the siphon 90 .
The bleach storing section 68 a is positioned in a rear and top of the main detergent storing section 62 a . Its bottom 68 c is distant from a bottom 66 a of the main detergent storing section 66 a , which is open at its top.
The siphon cover 91 is enough to cover a top surface of the bleach storing section 68 a , a hook for being connected to the bleach storing section 68 a and a hole 92 for placing bleach are formed therein.
A bottom of the siphon cover 91 has a siphon tube 93 that bleach and water moves upward at an interval with the siphon 90 , apart from the siphon 90 by predetermined distance.
The fabric softner storing section 68 b is situated a side of the bleach storing section 68 a . The fabric softner storing section 68 b , like the bleach storing section 68 a , has a siphon 96 protruded and a siphon cover 97 which provides a water drain passage with the siphon 96 .
A bottom of the siphon cover 97 has a siphon tube 99 that fabric softner and water moves upward at an interval with the siphon 96 , apart from the siphon 96 by predetermined distance.
The bypass passage 80 is placed between the subsidiary detergent chamber 68 and the powdered detergent chamber 66 , and is configured by a partition member vertically set, spaced apart from the subsidiary detergent chamber 68 toward the powdered detergent chamber 62 at a regular interval.
The partition member is provided by a partition plate 82 which includes a 1 st plate 83 vertically mounted between the main detergent storing section 62 a and the bleach storing section 68 a , and a 2 nd plate 84 vertically mounted between the preliminary detergent storing section 62 b and the fabric softner storing section 68 b.
A top 82 a of the partition plate 82 is placed lower than a top 66 c of the powdered detergent chamber 62 and a top of the subsidiary detergent chamber 68 . And, a bottom 82 b of the partition plate 82 is separated from a bottom 66 a of the detergent container by predetermined distance, so as to connect the powdered detergent chamber 62 and the drain passage 69 . The bottom 82 b of the partition plate is placed lower than a bottom 68 c of the subsidiary detergent chamber. It prevents that powdered detergent is excessively discharged through a space 86 between the bottom 82 b of the partition plate 82 and the bottom 66 a of the detergent container. A side of the partition plate 82 is fixed to the detergent container by being connected to the sides 66 d , 66 e of the detergent container and the partition wall 66 f , or is configured in a body of the detergent container. The partition plate 82 ′ including the 1 st plate 83 ′ and the 2 nd plate 84 ′, as shown in FIG. 8 , may have an opening 86 ′ at a lower part of the plate smaller than the drain passage 69 , and a plurality of holes 86 a at an upper part of the plate through which powdered detergent mixed with water flows to the bypass passage.
The dispenser 70 includes a front cover 72 and a bottom cover 78 having a main detergent water supply passage 73 , a preliminary detergent water supply passage 74 , a bleach water supply passage 75 , and a fabric softner water supply passage 76 .
A process with respect to the detergent container of the washing machine based on the embodiment of the present invention will be explained below.
Laundry is loaded in the drum 6 , powdered detergent is placed in the powdered detergent chamber 62 of the detergent container 60 , and washing operation is initiated by feeding water from a water supplier and detergent from the detergent container 60 to a tub 4 .
Referring to FIG. 5 , when an adequate or a small amount of powdered detergent is received in the powdered detergent chamber 62 of the detergent container 60 , water supplied from the water supplier drops into an open top side of the powdered detergent chamber 62 through the dispenser 70 . Dropped water is mixed with powdered detergent, and flows in the outlet 64 , after passing through the space 86 between the partition plate 82 and the bottom 66 a of the detergent container and subsequently the drain passage 69 , and then discharges to the housing 50 .
Water and powdered detergent discharged to the housing 50 is supplied to the tub 4 by flowing in the bellows tube 28 through the overflow 52 .
Referring to FIG. 6 , when an excessive amount of powdered detergent is received in the powdered detergent chamber 62 of the detergent container 60 , water supplied from the water supplier drops into the open top side of the powdered detergent chamber 62 through the dispenser 70 . Dropped water mixed with powdered detergent is intended to flow in the drain passage 69 through the space 86 .
However, water and powdered detergent cannot pass through the space 86 , since the space 86 is clogged by powdered detergent fully filled therein.
As water is continuously supplied through the dispenser 70 to the powdered detergent chamber 62 , a water level of the powdered detergent chamber 62 becomes higher. When the water level exceeds height of the partition plate 82 , water mixed with powdered detergent falls through the bypass passage 80 beyond the top side 82 a of the partition plate 82 .
Water and powdered detergent fallen through the bypass passage 80 flows in the outlet 64 through the drain passage 69 , and discharges to the housing 50 . Water and powdered detergent fallen through the bypass passage 80 washes out powdered detergent piled up the bottom side of the partition plate 82 , and moves to the outlet 64 . Water and powdered detergent is successfully discharged through the space 86 , after predetermined time.
Although excessive powdered detergent is accommodated in the powdered detergent chamber 62 of the detergent container 60 , the drain passage 69 is not clogged, and water and detergent is supplied to the tub 4 without any trouble.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
As describe above, the present invention provides a detergent container of a washing machine, even though powdered detergent is oversupplied, which prevents a drain passage from clogging and smoothly supplies water and powdered detergent to a tub at all times, resulting in improving the quality of the washing machine and enhancing the value of the washing machine.
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A detergent container of a washing machine in accordance with the present invention comprises a powdered detergent chamber to store powdered detergent, an outlet to discharge powdered detergent mixed with water in the powdered detergent chamber, a subsidiary detergent chamber to store bleach or fabric softner, a drain passage to guide powdered detergent mixed with water from the powdered detergent chamber to the outlet, and a bypass passage to allow powdered detergent mixed with water to bypass from the powdered detergent chamber to the drain passage. Even though an excessive volume of powdered detergent is placed in the powdered detergent chamber and the drain passage is clogged, powdered detergent mixed with water can be drained from the detergent container through the bypass passage, thus powdered detergent can be supplied to a tub of the washing machine without a hitch.
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BACKGROUND
[0001] In the hydrocarbon recovery industry, it is often desirable to chemically treat specific portions of well systems to, for example, enhance production, reduce corrosion of production components, reduce or avoid the buildup of problematic substances such as scale, paraffin, hydrates, etc. In some well systems, the application of chemicals to a target area can be a relatively straightforward process with little obstructive conditions or componentry to cause concern or consternation. In other well systems, however, chemical injection, as it is vernacularly termed, is less selectively achieved. In one example, well systems that are legally required to employ Surface Controlled Subsurface Safety Valves (SCSSV) present a difficult obstacle to chemical injection. The operator is faced with either having a fixed location for chemical injection, installed at the time that the TRSV is installed or a system that impacts functionality of the TRSV. Since running a tool through the SCSSV would create a safety issue by holding its closure mechanism open, considerable modification and complexity will be required to maintain a failsafe operation and protection of the well, in order to maintain compliance with applicable law. Since increased cost and complexity are always parameters of well operation to be avoided, the art is always receptive to alternative methods and apparatus that eschew such parameters.
SUMMARY
[0002] A chemical injection system includes a TRSV; a communication nipple in operable communication with the TRSV and positioned relative to the TRSV to be downhole of a flapper closure mechanism thereof when installed in a wellbore; a chemical injection line in fluid communication with the communication nipple; and a capillary sleeve receivable at the communication nipple and configured to sealingly convey fluid from the communication nipple to a remote location without affecting operation of the TRSV.
[0003] A method for injecting a chemical to an area of a wellbore downhole of a TRSV includes running a PCT to a preinstalled communication nipple downhole of the flapper closure mechanism of the TRSV; creating an opening in the communication nipple with the PCT thereby fluidly communicating a chemical injection line with an inside dimension of the communication nipple; and sealing a capillary sleeve with the inside dimension of the communication nipple at the opening.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Referring now to the drawings wherein like elements are numbered alike in the several Figures:
[0005] FIG. 1 is a schematic quarter-sectional view of a Tubing Retrievable Surface Controlled Subsurface Safety Valve (TRSCSSV or TRSV) and a communication nipple in accordance with an embodiment of the invention;
[0006] FIG. 2 is a quarter-section view of a Puncture Communication Tool (PCT) of the prior art;
[0007] FIG. 3 is a quarter section view of a capillary sleeve in accordance with an embodiment of the invention; and
[0008] FIG. 4 is an enlarged view of the communication nipple of FIG. 1 with the capillary sleeve illustrated in place within the punctured communication nipple.
DETAILED DESCRIPTION
[0009] Referring to FIGS. 1 , 2 , and 3 , a system 10 is illustrated that together facilitates chemical injection downhole of an SCSSV while retaining full function of the SCSSV. In one embodiment, the SCSSV is a TRSV as illustrated. Referring to FIG. 1 , a TRSV 12 is illustrated connected to a communication nipple 14 . The TRSV is commercially available, for example, from Baker Oil Tools, Houston, Tex. under Product Number H825603800 and therefore requires no specific discussion of its components or operation. It is to be appreciated that the chemical injection line is most commonly run at the outside dimension of the TRSV and is fixed there by known methods.
[0010] The TRSV is threadedly connected at thread 20 to a tubing spaceout string (not shown) or directly to the communication nipple 14 . Communication nipple 14 may be of a commercially available type sold, for example, by Baker Oil Tools, Houston Tex. under the product number H824063810, for example. It is to be appreciated that the chemical injection line 16 is fluidly connected to the nipple 14 at connection site 22 and in one embodiment, as illustrated, only after passing through a Chemical Injection Valve 24 (CIV), which is a check valve configuration. An appropriate CIV is, for example, commercially available from Baker Oil Tools Houston Tex. under product number H861039996. Connection site 22 is fluidly connected to a thin walled portion 26 of the nipple 14 that is intended to receive a puncture device from a subsequently run PCT 28 (for example, commercially available from Baker Oil Tools Houston Tex. under product number H822813815), see FIG. 3 . It is to be appreciated that several types of puncture devices 30 are available each being contemplated for use in this system.
[0011] Once the PCT 28 is run to position and operated, the chemical injection line is open at opening 27 and will flow chemical into the communication nipple 14 (the flow path of the produced hydrocarbons). As the provision of chemical at this location does not necessarily improve the production process, it is desirable to quickly trip the PCT 28 out of the hole and run in with a capillary sleeve 32 as disclosed herein.
[0012] Referring to FIGS. 3 and 4 , capillary sleeve 32 is a completely self-contained component that is run in the hole on a running tool (not shown) and then released after engagement with a profile 34 at an inside dimension of communication nipple 14 (see FIGS. 1 and 4 ). Profile 34 is engaged by one or more dogs 36 illustrated herein as four dogs, but other numbers are clearly substitutable. Dogs 36 and profile 34 are, in one embodiment, a snap-in/snap-out arrangement so that they are sufficiently engaged to support both the capillary sleeve 32 and a capillary tube 38 depending therefrom without further engagement to any structure extending through the TRSV and yet may be relatively easily disengaged by a retrieval tool (not shown) in the event that there is reason to remove the capillary sleeve 32 and dependent capillary tube 38 . It is important to note here that because of the configuration of the capillary sleeve 32 that makes it wireline retrievable, any malfunction of the system (CIV, Capillary tube, etc.) can be repaired easily by retrieving it to the surface. It is also possible of course to simply replace these components of the system rather than repair them when pulled. The dogs 34 may also be configured to respond to a retrieval tool such that a snap out is not necessary but rather engagement of a retrieval tool causes the dogs to retract.
[0013] The capillary sleeve 32 further includes, an arrangement configured to seal the opened communication nipple to contain the chemical injection fluid. In the illustrated example, the capillary sleeve includes a pair of seals 40 and 42 supported on an outside dimension of the capillary sleeve 32 at positions calculated to create a seal with the inside dimension 44 of the communication nipple 14 while straddling the opening in the nipple 14 . This configuration creates an annular sealed flow area for chemical injection fluid and thus a sealed pathway between the chemical injection line 16 and the capillary tube 38 . Between the seals 40 and 42 is a recessed area 46 of the sleeve 32 that enlarges the annular flow area for enhanced flow characteristics to for example avoid a flow restriction in this area. Within the recessed area 46 is an inlet 48 to receive the chemical injection fluid and a conduit 50 within the sleeve 32 that is fluidly connected with the inlet 48 and to the capillary tube 38 to convey fluid thereto for subsequent transport to a remote location such as a perforation area of the wellbore (not shown). Capillary tube 38 is fluidly connected to the conduit 50 through a suitable connection such as a threaded connection 52 as illustrated in FIG. 4 . In one embodiment, a redundant CIV 54 is included at a distal end 56 of capillary tube 38 to prevent wellbore fluid entering the capillary tube 38 . Each of the CIVs illustrated in this system provide a fail safe operation as they will automatically shut if sufficient hydraulic pressure is not maintained upon them from the surface. In addition to the foregoing, the capillary sleeve is configured to provide the largest inside dimension practicable to improve the flow cross section of the tool. Because the componentry (cross section) of the capillary sleeve is kept to a minimum, the patency (flow area for recovery of hydrocarbons through the capillary sleeve) can be maximized.
[0014] In one embodiment, referring to FIG. 1 , a Y-block 60 is employed so that the control line for the TRSV can be used for the chemical injection as well. The line is split and thereafter runs both to the TRSV and to the communication nipple. This is an optional configuration however, and a dedicated line for the chemical injection will be employed in some applications. In an application where a Y-block is used, one configuration will have the TRSV open at about 7,000 psi and the CIVs at 10,000 psi. This will ensure that the TRSV will reliably open before and independently of the chemical injection valves.
[0015] It is to be understood that the distance between the location of the TRSV 12 and the communication nipple 14 , and the distance between the nipple 14 and the capillary end 56 is largely limitless other than as practically limited simply by hydraulic friction. Each of these components may be spaced out as desired to ensure that chemical injection fluid is distributed as intended by the well operator. It is also possible to place multiple communication nipples 14 downhole that can individually be accessed to shorten the length of capillary tube 38 necessary to reach a target area with the chemical injection fluid.
[0016] A benefit of the system as disclosed herein is that the TRSV function is completely preserved using the disclosed configuration thereby not requiring a Wireline Retrievable Safety Valve (WRSV) or any other component extending through the TRSV. This of course reduces costs and maintains patency (flow area for recovery of hydrocarbons) in the flow area of the tubing string. Another benefit of this system is that there is no risk of producing hydrocarbons up the chemical injection prior to running a PCT and the capillary sleeve, which may not be necessary until later in the life of the well. The feature also provides benefits in thru tubing cement applications where cement is pumped through the ID of the tubing. During the initial completion of the well cement can be safely pumped through the ID of the communication nipple. The PCT will be able to punch through any cement (also scale and other solids that may deposit on the communication nipple) that remains on the wall of the communication nipple.
[0017] While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
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A chemical injection system includes a TRSV; a communication nipple in operable communication with the TRSV and positioned relative to the TRSV to be downhole of a flapper closure mechanism thereof when installed in a wellbore; a chemical injection line in fluid communication with the communication nipple; and a capillary sleeve receivable at the communication nipple and configured to sealingly convey fluid from the communication nipple to a remote location without affecting operation of the TRSV and method.
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FIELD OF THE INVENTION
[0001] The present invention relates to methods and compositions for treating and preventing cell necrosis. More specifically, the methods and compositions of the present invention prevent or treat necrosis by means of inhibiting the activity of intracellular elastase acting in the cells undergoing necrosis.
BACKGROUND OF THE INVENTION
[0002] Elastase is a serine protease that catalyses the degradation of proteins, including elastin, a major structural protein of mammalian connective tissue. The art has suggested that the inhibition of elastase may be effective in the treatment of various conditions and diseases.
[0003] For example, U.S. Pat. No. 4,683,241 indicates that elastase is believed to play an important role in the etiology of inflammatory connective tissue diseases. This patent discloses a class of phenolic esters exhibiting elastase inhibitory action.
[0004] U.S. Pat. No. 5,216,022 discloses the use of aromatic esters of phenylenedialkanoates as inhibitors of human neutrophil elastase (also known as leukocyte elastase), for treating numerous neutrophil elastase-mediated conditions.
[0005] U.S. Pat. No. 6,159,938 indicates that the inhibition of endogenous vascular elastase may be effective in treating pulmonary vascular disease and other related conditions.
[0006] Necrosis is the relatively uncontrolled process of cell death following perturbation to the cellular environment, resulting in cell rupture. Necrosis may be treated by the use of high pressure oxygen.
SUMMARY OF THE INVENTION
[0007] The inventors have unexpectedly found that intracellular elastase is involved in necrotic cell death, and that the inhibition of said enzyme within the affected cells may serve as an effective tool for treating and/or preventing cell necrosis and diseases associated therewith.
[0008] The present invention provides a method for treating and preventing necrosis of cells and diseases associated therewith, comprising inhibiting the enzymatic activity of one or more elastase enzymes within said cells.
[0009] In one aspect, the above mentioned method comprises administering to a subject a therapeutically effective amount of one or more elastase inhibiting agents, wherein said agents inhibit the enzymatic activity of intracellular elastase in the cells to be treated.
[0010] The present invention also encompasses a method for inhibiting and preventing cell necrosis in vitro, comprising causing an effective amount of one or more elastase inhibitors to enter the cells to be treated.
[0011] The inventors have also surprisingly found the inhibition of elastase within the affected cells may shift cell necrosis, at least partially, into apoptotic cell death. Thus, in a preferred embodiment, the invention provides a method for treating and preventing cell necrosis and diseases associated therewith, comprising:
[0000] inhibiting the enzymatic activity of elastase within said cells; and
inhibiting apoptotic cell death.
[0012] The present invention is also directed to pharmaceutical compositions for the treatment and/or prevention of cell necrosis and diseases associated therewith, wherein said compositions comprise therapeutically effective amounts of one or more agents that inhibit the enzymatic activity of one or more elastase enzymes in the cells to be treated. Thus, the abovementioned pharmaceutical compositions comprise one or more elastase inhibitors that are capable of entering the cells to be treated, in combination with one or more suitable pharmaceutically-acceptable excipients.
[0013] According to one preferred embodiment of the invention, the abovementioned pharmaceutical compositions further comprise one or more inhibitors of apoptosis.
[0014] In a further aspect of the present invention is provided the use of one or more elastase inhibitors in the preparation of a medicament for treating and/or preventing necrosis of cells and diseases associated therewith, wherein said elastase inhibitors are capable of entering said cells.
[0015] In a preferred embodiment, the invention is also directed to the use of one or more elastase inhibitors together with one or more inhibitors of apoptosis in the preparation of a medicament for treating and/or preventing necrosis of cells and diseases associated therewith, wherein said elastase inhibitors are capable of entering said cells.
[0016] The inhibitors of elastase activity used according to the invention for treating and preventing cell necrosis, and diseases associated therewith, are all capable of entering into the target cells, such that said inhibitors exert their inhibitory actions within said cells.
[0017] Preferably, necrosis may be treated or prevented according to the present invention in cells selected from the group consisting of neuronal cells, purkinje cell, hypocampal pyramidal cells, glial cells, cells of hematopoetic origin (such as lymphocytes and macrophages), hepatocytes, thymocytes, fibroblast, myocardial cells, epithelial cells, bronchial epithelial cells, glomeruli, lung epithelial cells, keratinocytes, gastrointestinal cells, epidermal cells, bone and cartilage cells.
[0018] Preferably, the diseases associated with cell necrosis, which may be treated and/or prevented according to the present invention, are selected from the group consisting of neurodegenerative disorders, leukemias, lymphomas, neonatal respiratory distress, asphyxia, incarcerated hernia, diabetes mellitus, tuberculosis, endometriosis, vascular dystrophy, psoriasis, cold injury, iron-load complications, complications of steroid treatment, ischemic heart disease, reperfusion injury, cerebrovascular disease or damage, gangrene, pressure sores, pancreatitis, hepatitis, hemoglobinuria, bacterial sepsis, viral sepsis, burns, hyperthermia, Crohn's disease, celiac disease, compartment syndrome, necrotizing procolitis, cystic fibrosis, rheumatoid arthritis, nephrotoxicity, multiple sclerosis, spiral cord injury, glomerulonephritis, muscular dystrophy, degenerative arthritis, tyrosemia, metabolic inherited disease, mycoplasmal disease, anthrax infection, infection with other bacteria, viral infections, Anderson disease, congenital mitochondrial disease, phenylketonuria, placental infarct, syphilis, aseptic necrosis, avascular necrosis, alcoholism and necrosis associated with administration and/or self-administration with, and/or exposure to, cocaine, drugs (e.g., paracetamol, antibiotics, adriamycin, NSAID, cyclosporine) chemical toxins such as carbon tetrachloride, cyanide, methanol, ethylene glycol and mustard gas, agrochemicals such organophosphats and paraquat, heavy metals (lead, mercury), other warfare organophosphats.
[0019] In another embodiment, the composition and methods of the invention may be used for the treatment and/or prevention of aging, by inhibiting the enzymatic activity of one or more elastase enzymes, more particularly the intracellular activity thereof, optionally together with the inhibition of apoptosis and the use of anti-aging agents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 graphically depicts the percentage of necrotic and apopoptic cells observed following treatment with and without oligomycin and anti-Fas.
[0021] FIG. 2 is a photographic representation of gelatin substrate gel electrophoresis results for lysates of U-937 cells treated/untreated with oligomycin and/or anti-Fas for 3 hours.
[0022] FIG. 3 is a photographic representation of gelatin substrate gel electrophoresis results obtained for lysates of U-937 cells treated/untreated with 0.5 mM KCN for 3 hours.
[0023] FIG. 4 is a photographic representation of a gelatin substrate electrophoretic gel, demonstrating that treatment of a cell lysate with KCN caused the appearance of a band of protease activity (lane B). This band disappeared when KCN was administered in the presence of 200 μM elastase inhibitor (lane C).
[0024] FIG. 5 presents results demonstrating the effect of elastase inhibitor III on KCN-induced necrosis in PC-12 cells. Panel A diagrammatically depicts the proportion of live, necrotic and apoptotic cells following various treatments. The numerical values for these proportions are given in the accompanying table. Panel B graphically depicts percentage PC-12 cell survival following treatment with KCN in the presence/absence of elastase inhibitor III.
[0025] FIG. 6 diagrammatically depicts the proportion of live, necrotic and apoptotic U-937 cells following treatment with KCN in the presence/absence of elastase inhibitor III. The numerical values for these proportions are given in the accompanying table.
[0026] FIG. 7 graphically illustrates the effects of elastase inhibitor III (panel B) and elastinal (Panel C) on Fas-induced apoptosis/necrosis in U-397 cells.
[0027] FIG. 8 graphically illustrates the percentage of necrotic and apoptotic PC-12 cells detected following treatment with/without oligomycin and/or STS.
[0028] FIG. 9 demonstrates the effect of an elastase inhibitor on STS-induced apoptosis in PC-12 cells.
[0029] FIG. 10 graphically illustrates the effect of an elastase inhibitor on STS-induced necrosis in PC-12 cells.
[0030] FIG. 11 demonstrates the effect of an elastase inhibitor on KCN-induced necrosis in PC-12 cells.
[0031] FIG. 12 graphically illustrates the effect of an elastase inhibitor on STS-induced necrosis in U-937 cells.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] The term “necrosis”, as used herein, encompasses cell necrosis states, as well as intermediates states, exhibiting necrotic and apoptotic characteristics. The term “elastase”, as used herein, refers to one or more forms of said enzyme.
[0033] Compounds exhibiting elastase inhibitory profile, which are herein referred to as elastase inhibiting agents, or elastase inhibitors, are known in the art, and are disclosed, for example, by Stein et. al. [Biochemistry 25, p. 5414 (1986)], Powers et al. [Biochim. Biophys. Acta. 485, p. 15 (1977)], U.S. Pat. No. 4,683,241, U.S. Pat. No. 5,216,022, and U.S. Pat. No. 6,159,938. Inhibitors of elastase are also commercially available from, e.g., Sigma-Aldrich or Calbiochem-Novabiochem Corporation.
[0034] Elastase inhibitors used according to the present invention are formulated together with one or more pharmaceutically acceptable carriers, which are non-toxic, inert solid, semi-solid or liquid fillers, diluent, encapsulating material or formulation auxiliary of any type. The pharmaceutical compositions can be administered to human and other mammalian subjects in any acceptable route, and preferably orally, parenterally or topically.
[0035] Solid dosage forms for oral administration include capsules, tablets, pills, powders and granules. In such solid dosage forms, the active compound is mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or dicalcium phosphate and/or fillers or extenders such as starches, lactose, sucrose, glucose and mannitol, binders such as carboxymethylcellulose and gelatin, humectants such as glycerol, disintegrating agents such as agar-agar, calcium carbonate and potato starch, absorbents and lubricants. The solid dosage forms can be prepared with coatings and shells according to methods known in the art.
[0036] Liquid dosage forms for oral administration include pharmaceutically acceptable solutions, emulsions, suspensions and syrups. In addition to the active compounds, the liquid dosage form may contain inert diluents commonly used in the art such as water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, propylene glycol and oils. Besides inert diluents, the oral compositions may also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring and perfuming agents.
[0037] Injectable preparations suitable for parenteral administration are provided in the form of pharmaceutically acceptable sterile aqueous or non-aqueous solutions, dispersions, suspensions or emulsions as well as sterile powders for reconstitution into sterile injectable solutions or dispersions prior to use. Examples of suitable aqueous or non-aqueous carriers or vehicles include water, Ringer's solution and isotonic sodium chloride solution. Sterile oils may also be employed as a suitable suspending medium. The injectable formulations can be sterilized, for example, by filtration through a bacterial-retaining filter, or by incorporating sterilizing agents therein.
[0038] Dosage forms for topical or transmucosal administration of elastase inhibitors according to the invention may include pastes, creams, lotions, gels, powders, solutions and sprays. In addition to the active ingredient, the pastes creams and gels may contain excipients such as fats, oils, waxes, paraffins, starch, cellulose derivatives, polyethylene glycols, talc, zinc oxide, or mixture thereof. Powders and sprays can contain excipient such as lactose, talcs, silicic acid, aluminum hydroxide, calcium silicates and mixtures thereof.
[0039] It should be noted that in addition to the medical or pharmaceutical use of topical and transmucosal compositions containing elastase inhibitors (and optionally, anti-apoptotic agents), the present invention also provides said compositions for use as cosmetic agents.
[0040] Other suitable formulations may be prepared by encapsulating the active ingredient in lipid vesicles or in biodegradable polymeric matrices, or by attaching said active ingredient to monoclonal antibodies. Methods to form liposomes are known in the art.
[0041] Dosage levels of active ingredients in the pharmaceutical compositions of this invention may be varied so as to obtain an amount of the elastase inhibitor that is effective to achieve the desired therapeutic response for a particular patient (i.e., a therapeutically effective amount). The selected dosage form will depend on the activity of the particular elastase inhibitor, the route of administration, the severity of the condition being treated and other factors associated with the patient being treated. Typical dose regimes are in the range of 0.1-200 mg/kg.
[0042] In another aspect, the present invention is directed to the treatment or prevention of cell necrosis by means of inhibiting the enzymatic activity of intracellular elastase(s), and, in addition, inhibiting apoptotic cell death. In a preferred embodiment of this aspect of the invention, the inhibition of apoptotic cell death is accomplished by means of administering to subject a therapeutic effective amount of an anti-apoptotic agent, which is preferably selected from the group consisting of [R]—N-[2-heptyl]-methylpropargylamine (R-2HMP), vitamin E, vitamin D, caspase inhibitors and the hydrophilic bile salt ursodeoxycholic acid. Other methods known in the art for inhibiting apoptosis, for example, by means of regulation of expression of pro- and anti-apoptotic proteins, may also be used according to the present invention. Such methods are described, for example, by Li et al. [Acta. Anaesthesiol Sin, 38(4), p. 207-215 (2000)].
EXAMPLES
Experimental Protocol
1. Models of Necrosis In Vitro
Staurosporine and Anti-Fas-Induced Necrosis
[0043] Human promonocytic U-937 cells in logarithmic phase were seeded at a concentration of 4×10 5 /ml. Afterwards the cells were washed twice and seeded again in glucose-free RPMI-1640 medium (Beit Haemek, Israel) supplemented with 2 mM pyruvate (Beit Haemek, Israel) and 10% dialyzed FCS (Gibco, BRL) for one hour.
[0044] The rat pheochromocytoma PC-12 cell line was propagated in DMEM medium (Gibco, BRL), supplemented with 5% heat-inactivated calf serum, 10% heat-inactivated horse serum, and 2 mM L-glutamine. PC-12 cells in logarithmic phase were seeded at a concentration of 1.2×10 5 /well in 24-well plates (Cellstar). Then the cells were washed twice and maintained in glucose-free RPMI-1640 medium (Beit Haemek, Israel), and supplemented with 2 mM pyruvate and 10% dialyzed FCS for one hour. U-937 and PC-12 cells were incubated with and without 1 μM oligomycin (Sigma) for 45 min, and cells were treated with or without 1.25 μM staurosporine (STS) (Sigma) for an additional seven hours in U-937 cells or five hours in PC-12 cells. Alternatively, cells were treated with or without 100 ng/ml anti-Fas (Upstate biotechnology, USA) for the same time period.
KCN-Induced Necrosis
[0045] U-937 and PC-12 cells cultured in complete RPMI-1640 medium were washed and seeded in glucose-free RPMI-1640 medium, as described above, and treated with or without 0.5 mM KCN (Merck, Germany) for seven hours with U-937 cells, or for five hours with PC-12 cells.
2. Testing of Elastase Inhibitor
[0046] 200 μM elastase inhibitor III (MeOSuc-Ala-Ala-Pro-Val-CMK from Calbiochem) when added was administered 30 min before addition of the inducers. The inhibitor was dissolved in DMSO to a concentration of 100 mM. The final concentration of DMSO in the system was 0.2%, and was added to all treatments. In separate experiments, 200 μM of an elastase inhibitor (CE1037, manufactured by Cortech Inc.) was administered 30 min before addition of the inducers. The inhibitor was dissolved in PBS.
3. Cell Death Assay
Trypan Blue Exclusion
[0047] At each time point, cell viability was determined by the trypan blue exclusion method (Daniel C P, Parreira A., et al. Leukemia Res. 11:191-196 (1987). Assays were performed in duplicate.
Morphological Quantification of Apoptosis and Necrosis
[0048] Cells undergoing morphological changes associated with apoptotic or necrotic cell death were monitored as described by McGahon et al. [Methods Cell Biol, 46: p. 153-85 (1995)]. Briefly, 1 ml of the cells was collected and centrifuged. The pellet was resuspended in a 20-fold dilution of the dye mixture (composed of 100 μg/ml acridine orange and 100 μg/ml ethidium bromide in PBS), placed on a glass slide and viewed on an inverted fluorescence microscope. A minimum of 200 cells was scored for each sample.
Preparation of Cell Lysates
[0049] 4×10 7 U-937 cells, treated or untreated with the various inducers, were collected after three hours of incubation, washed twice with ice-cold PBS and resuspended at 10 8 /ml in ice-cold lysing buffer (50 nM Tris-HCl pH 7.5, 0.1% NP-40, 1 mM DTT, 100 μM leupeptin and 100 μM TLCK). The cells were broken by the use of a polytron device (4 cycles of 7 seconds each) on ice, and the debris was pelleted by centrifugation in an ultracentrifuge at 120,000×g for 30 minutes at 4° C. The supernatant was used for further studies or stored at −70° C. The protein content of each sample was determined by the protein assay (BioRad).
5. Electrophoresis
[0050] Electrophoresis on a gelatin substrate gel was performed as previously described (Distefano J. F., Cotto C. A., et al. Cancer Invest. 6, 487-498, (1988)). Proteases were reversibly inactivated by addition of 100 μl aliquots of the cell lysates containing 200 μg protein to 50 μl of 0.625 M Tris-HCl buffer, pH 6.8, with 2.5% SDS, 10% sucrose and 0.03% phenol red. Samples were then electrophorated using 0.1% gelatin copolymerized in 11% polyacrylamide gel. After electrophoresis, the gels were subjected to three repeated immersions in 0.1 M Tris-HCl buffer, pH 7.0, containing 2.5% (V/V) Triton-x-100 in order to remove the SDS and reactivate the proteases. The gels were sliced and incubated overnight at 37° C. in 0.1 M glycine-NaOH buffer, pH 7.0, with or without 100 μM TPCK (chymotrypsin-like serine protease inhibitor) and 100 μM elastinal (elastase-like serine protease inhibitor). The bands of protease activity were developed with amido black staining.
Results
1. Anti-Fas-Induced Apoptosis/Necrosis in U-937 Cells
[0051] FIG. 1 indicates that treatment with anti-Fas induced about 60% apoptosis as compared to the control. Oligomycin is inactive by itself, however, addition of 100 ng/ml anti-Fas to oligomycin switched apoptotic cell death to necrotic cell death. Under these conditions, about 70% necrosis occurred and apoptosis returned to control level. Nuclear morphology was determined and analyzed by fluorescence microscope after double-staining with acridine orange and ethydium bromide.
2. Induction of Elastase-Like Activity During Necrotic Cell Death Induced by Anti-Fas in the Presence of Oligomycin
[0052] U-937 cells were maintained in glucose-free medium preincubated with or without 1 μM oligomycin for 45 min and treated with or without 100 ng/ml anti-Fas for three hours. Following this, cell lysates were prepared as described in “Experimental protocol” and applied to a gelatine substrate gel electrophoresis. The results, which are presented in FIG. 2 indicate that treatment with anti-Fas and oligomycin caused the appearance of a band of protease activity (line D), which was not found in the untreated control cells (lane A), anti-Fas-treated cells (lane B), or oligomycin-treated cells (lane C). This band disappeared in the presence of 100 μM elastinal (lane D), but not in the presence of 100 μM TPCK (lane D), indicating that treatment with anti-Fas and oligomycin induced an elastase-like activity, but not a chymotrypsin-like activity.
3. Induction of Elastase-Like Activity During Necrotic Cell Death Induced by KCN
[0053] U-937 cells were treated with or without 0.5 mM KCN for three hours and then cell lysates were prepared as described in “Experimental protocol” and applied to a gelatine substrate gel electrophoresis. The results, which are presented in FIG. 3 , show that treatment with KCN caused the appearance of a band of protease activity (lane B), which was not found in the untreated control cells (lane A). This band disappeared in the presence of 100 μM elastinal (lane B), but not in the presence of 100 μM TPCK (lane B), indicating that treatment with KCN induced an elastase-like activity, but not a chymotrypsin-like activity.
4. Effect of Elastase Inhibitor on Induction of Elastase-Like Activity During Necrotic Cell Death
[0054] U-937 cells were treated with or without 5 mM KCN. 200 μM elastase inhibitor (Cortech) was added for three hours and then cell lysates were prepared as described in “Experimental protocol” and applied to a gelatine substrate gel electrophoresis. The results are presented in FIG. 4 . It can be seen that treatment with KCN caused the appearance of a band of protease activity (lane B), which was not found in the untreated control cells (lane A). This band disappeared when KCN was administered in the presence of 200 μM elastase inhibitor (lane C).
5. Prevention of KCN-Induced Necrosis by Elastase Inhibitor III in PC-12 Cells
[0055] Exposure of PC-12 cells to 0.5 mM KCN induced massive necrotic cell death compared to the control. Addition of elastase inhibitor III which was inactive by itself significantly inhibited necrosis induced by KCN ( FIG. 5 , B). The protective effect of elastase inhibitor III is also seen when cell survival was determined under the same conditions by trypan blue exclusion ( FIG. 5 , A).
6. Inhibitory Effect of Elastase Inhibitor III on KCN-Induced Necrosis in U-937 Cells
[0056] Treatment with KCN caused 95% necrosis as compared to 10% in the control. Addition of elastase inhibitor III with KCN markedly reduced necrotic cell death to 21%, and shifted 22% of the necrotic cell death to apoptotic cell death. 52% of the cells were protected from necrotic cell death by this inhibitor. Elastase inhibitor III did not cause any cell damage ( FIG. 6 ).
7. Inhibitory Effect of Permeable Versus Non-Permeable Elastase Inhibitor on Anti-Fas-Induced Necrosis
[0057] FIG. 7A shows anti-Fas-induced apoptosis/necrosis. Under these conditions cells were exposed to a permeable elastase inhibitor (Cortech Inc.). This exposure completely abrogated apoptotic as well as necrotic cell death ( FIG. 7B ). The non permeable elastase inhibitor-elastinal had no effect in this system ( FIG. 7C ).
8. STS-Induced Apoptosis/Necrosis in PC-12 Cells
[0058] FIG. 8 indicates that treatment with 1.25 μM STS induced about 73% apoptosis as compared to the control. Oligomycin is inactive by itself, however, addition of STS to oligomycin switched apoptotic cell death to necrotic cell death. Under these conditions, about 70% necrosis occurred and apoptosis returned to control level. Nuclear morphology was determined and analyzed by fluorescence microscope after double-staining with acridine orange and ethidium bromide.
9. Inhibition of STS-Induced Apoptosis by Elastase Inhibitor in PC-12 Cells
[0059] Exposure of PC-12 cells to 1.25 μM STS induced massive apoptotic cell death as compared to the control. Addition of 200 μM elastase inhibitor (Cortech, Inc.) which was inactive by itself significantly inhibited apoptosis induced by STS ( FIG. 9 ).
10. Prevention of STS-Induced Necrosis by Elastase Inhibitor in PC-12 Cells
[0060] As seen in FIG. 10 A, 1.25 μM STS with 1 μM oligomycin induced about 70% necrosis. 200 μM elastase inhibitor was inactive by itself, but completely abrogated necrosis-induced by STS. Under the same conditions 100 μM elastase inhibitor markedly reduced necrotic cell death to 9%, and shifted 39% of the necrotic cell death to apoptotic cell death ( FIG. 10B ).
11. Inhibitory Effect of Elastase Inhibitor on KCN-Induced Necrosis in PC-12 Cells
[0061] Exposure of PC-12 cells to 0.5 mM KCN induced massive necrotic cell death as compared to the control. Addition of 200 μM elastase inhibitor which was inactive by itself significantly inhibited necrosis induced by KCN ( FIG. 11 ).
12. Effect of Elastase Inhibitor on STS-Induced Necrosis in U-937 Cells
[0062] As seen in FIG. 12 treatment with STS in the presence of oligomycin markedly reduced cell survival as compared to control. Elastase inhibitor had a slight effect by itself, but it significantly inhibited cell killing induced by STS and oligomycin. The inhibitory effect was measured during prolong incubation of 48 hours. Cell viability was measured by trypan blue exclusion. Similar results were obtain for apoptosis (Data not shown).
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A method for treating and/or preventing cell necrosis and diseases associated therewith, comprising the inhibition of one or more elastase enzymes within said cells.
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FIELD OF THE INVENTION
The present invention relates to a ventilation device for an automotive vehicle and, more particularly, to an automobile ventilation device which can prevent an increase in temperature within an automotive vehicle left in bright sun.
BACKGROUND OF THE INVENTION
The temperature within a vehicle parked for a long time in bright sun, particularly in summer, becomes very high, and in some cases above 100° C. The air conditioning system of such a parked vehicle takes a long time before achieving its cooling effect and, as such, the interior of the vehicle is quite inhospitable for the driver and passengers.
To ventilate a parked vehicle, various types of ventilation systems having solar operated Ventilation fans have been proposed in the prior art. One type of solar powered ventilation system is known from, for example, Japanese Patent Publication No. 59(1984)-51,451, entitled "Ventilation Device For Automotive Vehicle," issued on Dec. 14, 1984. This ventilation device, as is schematically illustrated in FIG. 1, has a ventilation fan e disposed in a duct with its air inlet f opening inside the vehicle a and its air outlet g opening outside the vehicle a. The ventilation fan e is connected in series to a solar cell h attached to a rear window glass b as a power source by a bimetal switch i disposed in the vehicle a. This bimetal switch i has a switching temperature set to a specific temperature. The ventilation fan e is, accordingly, automatically operated to discharge air within the vehicle when the temperature within the parked vehicle reaches the specific temperature, i.e., the switching temperature of the bimetal switch.
However, in such a known solar powered ventilation system, since the detection of specific fan actuation temperature is effected independently of the temperature outside the vehicle, the ventilation fan works in response to the temperature inside the vehicle only. Therefore, if the switching temperature of the bimetal switch is set lower than temperatures at which a driver or passengers feel comfortable in the vehicle, the ventilation fan will be actuated even in circumstances in which it is not necessary to ventilate the vehicle, because the temperature in the vehicle is higher than the specific temperature. Such a circumstance will often be present when the temperature inside the vehicle is higher than the specific temperature but the temperature outside the vehicle is too low for comfortable ventilation.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of the invention to provide an automobile ventilation device which ventilates properly according to external temperatures and which operates only when ventilation is needed.
The above object of the present invention is achieved by providing a solar powered ventilation device for an automotive vehicle which has ventilation means including an electric motor operated ventilation fan operated by electric power to ventilate, or exhaust, air in the automotive vehicle. A solar cell, disposed on a body of the automotive vehicle, for example, a roof of the automotive vehicle, is electrically connected to the electric motor operated ventilation fan, and absorbs sunlight. The solar cell converts the radiation of the sunlight to electric power to be supplied to the electric motor operated ventilation fan. The electric motor operated ventilation fan is disconnected from the solar cell by and when control means detects a predetermined temperature outside the automotive vehicle.
The control means has a temperature sensor disposed close to an air outlet of a Ventilation duct of the ventilation means and switch means which switches on when the temperature sensor detects the predetermined temperature outside of the vehicle.
In one specific embodiment, the control means comprises an exterior thermostat switch, disposed close to the air outlet of the ventilation duct, connected in series between the ventilation fan and solar cell. The exterior thermostat switch switches itself on at a switching temperature set equal to the predetermined temperature outside the vehicle so as to electrically connect the solar cell to the electric motor operated ventilation fan, thereby supplying electric power to the motor operated Ventilation fan from the solar cell.
The control means preferably further includes an interior thermostat switch disposed inside the automotive vehicle and connected in series to the exterior thermostat switch. The interior thermostat switch has a switching temperature higher than the predetermined temperature at which the exterior thermostat switch switches itself off. The interior thermostat switch, when the temperature inside the vehicle reaches the switching temperature of the interior thermostat switch, switches itself off, cutting electric power to the motor operated ventilation fan from the solar cell.
Since the ventilation fan is operated only when the temperature outside the vehicle is higher than a particular switching temperature, which is set to a specific temperature, the ventilation device is set into action mostly when a vehicle is parked under the blazing sun in summer for a long time and the inside of the vehicle becomes too hot. However, in winter, since the inside of the vehicle does not becomes so hot, even when the vehicle is parked under the sun for a long time, and since the outside temperature may be too low for the vehicle to be comfortably ventilated, the ventilation device is not actuated. Accordingly, the inside of the parked vehicle is kept warm in winter.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the present invention will be apparent from the following description of a preferred embodiment thereof when considered in conjunction with the appended drawings, wherein same or similar parts are designated by the same reference numerals throughout the several drawings, and in which:
FIG. 1 is a cross-sectional view showing part of an automotive vehicle in which a prior art ventilation device is incorporated;
FIG. 2 is a schematic perspective view showing an automotive vehicle in which a ventilation device in accordance with a preferred embodiment of the present invention is incorporated;
FIG. 3 is an explanatory, enlarged cross-sectional view as seen along line III--III of FIG. 2;
FIG. 4 is a diagram showing a driving circuit for the ventilation device shown in FIG. 2;
FIG. 5 is a schematic side view showing an automotive vehicle, partly cut away, in which a ventilation device in accordance with another preferred embodiment of the present invention is incorporated; and
FIG. 6 is an explanatory, enlarged cross-sectional view of the ventilation device shown in FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 2 through 4, the present invention is embodied in a ventilation device incorporated in an automotive o vehicle 1. Car body 2 of the automotive vehicle 1 is provided with an electric motor operated ventilation fan 41 forming part of the ventilation device 40. The ventilation fan 41 is located inside part of a rear fender 4 of the car body 2 which is covered by a rear bumper 5. The ventilation device 40 includes an exterior thermostat switch 6, such as a bimetal switch, which closes to operate or switch on at a predetermined switching temperature, which is set to a specific exterior temperature, for example, about 35° C. (59° F.). The bimetal switch 6 is disposed inside the bumper 5 so as to detect the exterior temperature outside the vehicle 1. A panel of solar cells 11 is disposed on a roof 3 of the automotive vehicle. The solar cells 11, used as a power supply for the electric motor operated ventilation fan 41, absorb sunlight, converting the radiation to electric power.
As is shown in detail in FIG. 3, the lower part of the rear fender 4, covered by the bumper 5, is formed with an opening 7 as an air outlet from which an exhaust duct 43, tapering toward its inner end and inclining upwardly, extends substantially parallel to the center axis of rotation of the ventilation fan 41 in a trunk room or volume 9. This trunk room 9 communicates, in a known manner, with the inside of the automotive vehicle 1 for ventilation. The exhaust duct 43 is provided, at its inner end, with a cylindrical frame 42 for supporting therein the ventilation fan 41. The exterior thermostat switch 6 is held by a bracket 8 to front to, or face, the exhaust air outlet or opening 7 of exhaust duct 43 so as tO be exposed to exhaust air passed through the exhaust duct 43 when the fan 41 is actuated.
As is shown in FIG. 4, the electric motor operated ventilation fan 41 of the ventilation device 40 is controlled by control means or power supply control circuit 20, in which the ventilation fan 41 is connected in series to the solar cells 10 through the thermostat switch 6 and a main switch 21, connected in series to each other. The main switch 21, disposed inside the vehicle 1, may be either a manually operated switch, which is switched on when ventilation is wanted or expected, or of an automatically operated, normally closed switch. If main switch 21 is an automatically operated, normally closed switch, switch 21 is constructed as a thermostat switch which opens, or switches off, when the temperature inside the vehicle 1 reaches a desired, i.e., sufficiently cool, interior temperature, for example, about 20° C. (68° F.), at which the driver and/or passengers in the vehicle 1 feel comfortable.
If a manually operated switch for the main switch 21 is employed, it is desirable to adapt the exterior thermostat switch 6 to close, or switch on, at specific exterior temperature of, for example, about 15° C. (59° F.), to enable operation of the fan 41. It is also desirable to adapt the exterior thermostat switch 6 to open, or switch off, at a second switching temperature, i.e., a desired interior temperature, for example, about 20° C. (68° F.). It should again be noted that the interior temperature is detected by the exterior thermostat switch 6 as air from inside the vehicle is blown over the switch 6 by fan 41.
When the exterior thermostat switch 6 detects that the temperature of air outside the automotive vehicle 1 is equal to or greater than the specific exterior temperature, namely the lower switching temperature of the thermostat 6, switch 6 turns itself on, i.e., closes. When switch 6 is closed while the manually operated interior switch 21 is also switched on or closed, the power supply circuit 20 supplies electric power generated by the solar cells 11 to operate the ventilation fan 41 to operate the fan. As soon as the ventilation fan 41 begins its operation, it forces hot air inside the passenger chamber and trunk of the automotive vehicle 1 out through the exhaust duct 43, thereby ventilating the chamber and trunk so as to gradually lower the temperature inside the automotive vehicle 1. Because the exhaust air from the exhaust air outlet or opening 7 blows over the thermostat switch 6, the thermostat switch 6 is gradually cooled. When the automotive vehicle 1 is sufficiently ventilated and the temperature inside the automotive vehicle 1 passes below the lower specific or switching temperature of thermostat switch 6, the thermostat switch 6 opens, or switches off, to shut down the power supply circuit 20, so as to stop the ventilation fan 41.
The ambient temperature present around the thermostat switch 6 may rise higher than the specific temperature switching the thermostat switch 6, for example because of heat from an exhaust pipe of the engine after starting the engine of the automotive vehicle 1. If the ambient temperature around thermostat switch 6 rises higher than the specific temperature of switch 6, the ventilation device 40 is actuated independently from the temperature outside the automobile vehicle 1. However, as soon as the ventilation fan 41 operates, it blows off the heated air surrounding the thermostat switch 6, so that the thermostat switch 6 can detect the actual external temperature outside the automobile vehicle 1 soon after the engine starts.
As long as the interior switch 21 is open, or switched off, either manually, or automatically when the switch 21 detects an interior temperature which is lower than the specific temperature which closes the main switch 21, the ventilation fan 41 is not actuated, even though the thermostat switch 6 has detected the specific exterior temperature and is closed to switch or turn itself on.
When the temperature outside the automobile vehicle 1 is lower than the specific temperature which causes switch 6 to close, the thermostat switch 6 is maintained open or off, so that no ventilation takes place even though the temperature inside the automotive vehicle 1 is high. It is considered that when the temperature of air outside the automobile vehicle 1 is lower than the specific temperature, the temperature of air inside the automotive vehicle 1 will not rise so high as to give discomfort to the passengers in the automotive vehicle 1. Accordingly, no ventilation is required. This results in eliminating operation of the ventilation device 40 when no ventilation is required. It should be noted that arranging the exhaust duct 43 inside the rear bumper 5 prevents hot exhaust air from the interior of the vehicle from blowing on persons standing near the rear of the automotive vehicle 1.
Referring to FIGS. 5 and 6, showing the ventilation device according to another preferred embodiment of the present invention, an exhaust duct 43a, which is similar in function to but different in structure from the exhaust duct 43 of the previous embodiment, is disposed near a floor panel 10 of the trunk and extends from the cylindrical frame 42 at an angle smaller than a right angle with respect to the center axis of rotation of the ventilation fan 41. The exhaust duct 43a is further shaped at its end connected to the air outlet opening 7 to be elliptical so as to locate the front periphery of upper portion of the cylindrical frame 42 close to the inner surface of the rear fender 4. The elliptical end of the exhaust duct 43 is provided with a guide plate 44 at its upper portion to direct exhaust air forced by the ventilation fan 41 downwardly and outward. Such an arrangement of the exhaust duct 43a and guide panel 44 provides additional help in preventing exhaust air from blowing on persons standing near the rear of the automotive vehicle 1.
The electric motor operated ventilation fan 41 of the ventilation device 40 of this embodiment is also controlled by the same control means or power supply circuit 20 as shown in FIG. 4.
If it is desired, the passenger chamber of the automotive vehicle 1 may be directly connected to the ventilation device 40, in particular the ventilation fan 41, by way of a .duct so as to exhaust air only in the passenger chamber rather than in both the passenger chamber and trunk room.
It is to be understood that although the invention has been fully described in detail with respect to a preferred embodiment thereof, nevertheless, various other embodiments and variations are possible which are within the spirit and scope of the invention, and such embodiments and variations are intended to be covered by the following claims.
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A solar powered ventilation device for a vehicle has a solar cell disposed on a car body and electrically connected to an electrically operated ventilation system, and a controller for detecting a predetermined temperature outside the car to electrically disconnect the ventilation system from the solar cell. The ventilation system is supplied with electric power from the solar cell, thereby ventilating or exhausting air from the vehicle interior only when the exterior temperature is higher than the predetermined temperature.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application which claims priority from U.S. provisional application No. 61/763,790, filed Feb. 12, 2013.
FIELD OF THE DISCLOSURE
[0002] The present disclosure relates generally to support structures, and particularly to rig support structures for use in oil drilling rigs
BACKGROUND OF THE DISCLOSURE
[0003] Box-on-box style land-based drilling rigs are made up of multiple stacked girder-framed box substructure. Swing-up or self-elevating style land-based drilling rigs are made up of a top, girder-frame box coupled, by pivoting elevator legs, to a bottom, girder-frame box substructure. Typically, hardware known as spreader beams may be used to, for example keep parallel box substructures in relative alignment along, for example, each side of a wellbore or well-center. Conventional spreader beams are pinned in place, and either require complete removal or allow only horizontal rotation. Land-based drilling rigs may be skidded from location to location to drill multiple wells within the same well site. In certain situations, it is necessary to skid the drilling rig across an already drilled well for which there is a well-head in place. In these situations, the spreader beams must be removed completely to allow the rig to traverse any such obstructions. Once the rig has been skidded, the spreader beams may be replaced. Spreader beams may be located near the ground, in some cases within three feet of ground level.
SUMMARY
[0004] A spreader beam for coupling between a first and a second parallel substructure is disclosed. The spreader beam includes a first spreader beam section, where the first spreader beam section is pivotably coupled to the first substructure, and a second spreader beam section, where the second spreader beam section is pivotably coupled to the second substructure. The first and second spreader beam sections are positioned to, in an extended position, selectively couple to each other.
[0005] The present disclosure also provides for a method. The method may include positioning a drilling rig at a first position in a wellsite. The drilling rig may include a first and a second parallel substructure; a spreader beam positioned to couple between the first and second parallel substructures. The spreader beam may include: a first spreader beam section, the first spreader beam section pivotably coupled to the first substructure; a second spreader beam section, the second spreader beam section pivotably coupled to the second substructure; the first and second spreader beam sections positioned to, in an extended position, selectively couple to each other. The method may further include decoupling the first and second spreader beam sections; pivoting the first and second spreader beam sections to a retracted position; moving the drilling rig to a second position.
[0006] The present disclosure also provides for a spreader beam for coupling between a first and a second parallel substructure of a drilling rig. The spreader beam may include a first spreader beam section. The first spreader beam section may be pivotably coupled to the first substructure. The first spreader beam section may be pivotable in at least one of a horizontal plane and a vertical plane. The first spreader beam section may include a first spreader beam subsection and a second spreader beam subsection, the first and second spreader beam sections being slidingly coupled such that by extending the second spreader beam subsection past the first spreader beam subsection, the length of the spreader beam section is increased. The spreader beam may also include a second spreader beam section. The second spreader beam section may be pivotably coupled to the second substructure, the second spreader beam section may be pivotable in at least one of a horizontal plane and a vertical plane. The first and second spreader beam sections may be positioned to, in an extended position, selectively couple to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
[0008] FIG. 1 a is an end view of a section of a box-on-box drilling rig consistent with at least one embodiment of the present disclosure.
[0009] FIG. 1 b is a plan view a section of a box-on-box drilling rig consistent with at least one embodiment of the present disclosure.
DETAILED DESCRIPTION
[0010] It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
[0011] FIG. 1 a depicts box-on-box rig 20 . Box-on-box rig 20 may include two parallel substructures 10 . Substructures 10 may be maintained a selected distance from each other by means of one or more spreader beams 30 . In one embodiment, spreader beam 30 includes spreader beam sections 1 . Each spreader beam section 1 is attached to a corresponding substructure 10 at a corresponding spreader beam joint 4 . In normal operation, spreader beam sections 1 may be joined by center spreader beam coupler 50 .
[0012] During a skidding operation, box-on-box rig 20 may need to traverse an obstruction, such as a wellhead, which is straddled by substructures 10 as box-on-box rig 20 skids thereover. When skidding past an obstruction taller than the distance between ground level and spreader beams 30 , spreader beams 30 may interfere with the obstruction and prevent box-on-box rig 20 from traversing the obstruction. In some embodiments, spreader beam sections 1 may be decoupled at spreader beam coupler 50 . In some embodiments, each spreader beam section 1 may be pivotably coupled to a corresponding substructure 10 , thus allowing spreader beam section 1 to pivot out of the way once decoupled at spreader beam coupler 50 . As depicted in FIG. 1 , spreader beam sections 1 may pivot upward and downward at spreader beam joints 4 . In some embodiments, spreader beam sections 1 may instead be positioned to pivot horizontally about spreader beam joints 4 . In some embodiments, spreader beam joints 4 may be universal joints which may be used to allow spreader beam sections 1 to pivot both upward and downward, as well as horizontally. Once spreader beam sections 1 are decoupled and temporarily pivoted out of the way, box-on-box rig 20 may continue to skid over the obstruction. Once the obstruction is cleared, spreader beam sections 1 may be recoupled spreader beam coupler 50 . In some embodiments, a locking mechanism may be included on one or more of substructure 10 or spreader beam section 1 , allowing spreader beam sections 1 to be retained against substructure 10 to, for example, prevent them from freely moving during the skidding operation or during transportation.
[0013] In some embodiments of the present disclosure, each spreader beam section 1 may include two or more sections positioned to, for example, telescope and increase the length of spreader beam section 1 . By reducing in length, spreader beams 1 may, for example in a situation in which the distance between substructures 10 is greater than one half the distance between spreader beam 30 and ground level, allow spreader beams 1 to be secured to substructures 10 in the downward position without, for example, dragging on the ground as box-on-box rig 20 is skidded.
[0014] In some embodiments, such as that depicted in FIG. 1 b , spreader beam 30 may be reinforced by one or more k-braces 40 . K-braces 40 may provide support to spreader beams 30 and, for example, increase the rigidity of substructures 10 . When skidding past an obstruction greater than the distance between ground level and K-braces 40 and spreader beams 30 , K-beams 40 may be configured to be removed by, for example, unbolting or unpinning. In some embodiments of the present disclosure, K-braces 40 may be pivotably coupled to substructures 10 by K-brace joints 2 . In some embodiments, K-brace joints 2 may allow for the pivoting of K-braces in a horizontal axis or a vertical axis. In some embodiments, K-brace joints 2 may be adapted to allow for the pivoting of K-braces 40 in both horizontal and vertical directions. In some embodiments, K-braces 40 may be coupled to spreader beam segments 1 . In some embodiments, K-braces 40 may be positioned to pivot upward or downward as spreader beam segments 1 pivot upward or downward. In some embodiments, a locking mechanism may be included on one or more of substructure 10 or K-braces 40 , allowing K-braces 40 to be retained against substructure 10 to, for example, prevent them from freely moving during the skidding operation.
[0015] In some embodiments, spreader beams 30 and/or K-braces 40 may be located within 5 feet of the ground level. In some embodiments, spreader beams 30 and/or K-braces 40 may be located at least 6 feet above ground level. In other embodiments, K-braces 40 and/or spreader beams 30 may be located between about 5-8 feet above ground level. In some embodiments, K-braces 40 and/or spreader beams 30 may be located about 7 feet above ground level. By locating K-braces 40 and spreader beams 30 higher above ground level, obstructions such as well-heads may be skidded over without removal or reconfiguration of spreader beams 30 and K-braces 40 .
[0016] In some embodiments, K-braces 40 may be at an angle of between about 20° and 75° to spreader beams 30 . In some embodiments, K-braces 40 may be at an angle of between about 30° and 60° to spreader beams 30 . In some embodiments, K-braces 40 may be at an angle about 45° to spreader beams 30 .
[0017] The foregoing outlines features of several embodiments so that a person of ordinary skill in the art may better understand the aspects of the present disclosure. Such features may be replaced by any one of numerous equivalent alternatives, only some of which are disclosed herein. One of ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. One of ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
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A spreader beam includes a first spreader beam section, where the first spreader beam section is pivotably coupled to the first substructure and a second spreader beam section, where the second spreader beam section is pivotably coupled to the second substructure. The first and second spreader beam sections are positioned to, in an extended position, selectively couple to each other.
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REFERENCE TO RELATED APPLICATIONS
This application is based on Provisional Patent Application 61/001,781 filed on Nov. 5, 2007.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the removal by centrifugal force and by coalescence of water and other impurities from diesel fuel, jet fuel, gasoline, kerosene, bio-diesel fuel, ethanol enriched fuel, heating oil, hydraulic oil, cutting oils, and other liquids with a specific gravity of less than one (1).
2. Description of the Prior Art
U.S. Pat. No. 6,042,722 issued to Ronald L. Lenz Mar. 28, 2000 An apparatus for separating water and contaminants from a fuel which has a specific gravity which is lower than that of water. Contaminated fuel is drawn from a bottom of a tank and passed into a separator. The water stays at the bottom of the separator and is drained off. The fuel is forced upwardly from which any droplets of water flow along collector plates and fall to the bottom of the separator. The fuel is passed through a filter which removes any particles of matter then the fuel is directed back to the tanks. The process can be repeated for as many times as necessary to cleanse the fuel of water and contaminates.
OBJECTS AND SUMMARY OF THE INVENTION
The object of this invention is to improve the apparatus and method for de-watering and purifying fuel oils and other liquids as described in U.S. Pat. No. 6,042,722.
It is therefore an advantage of this invention to provide modified modular components consisting of but not limited to a water-separator module, a filter module, a pump module, and a control module to be used in plurality or as stand alone components to de-water and purify fuel oils and other liquids.
Another advantage of this invention is to de-water and purify fuel oils and other liquids, utilizing one or more of the modular components of this invention in the fuel system which operates an engine.
Another advantage of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in a hydraulic system.
Yet another advantage of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in an engine lubricating system.
Yet another advantage of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in a machinery lubricating system.
Still another advantage of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in a mobile storage tank cleaning system.
While another object of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention made from alloys of metals, plastics, or composites.
Yet another object of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in concert with a water detecting device or timer to automatically turn the system on and off.
Yet another advantage of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in various sizes for engine fuel systems as small as one (1) Horsepower to engine fuel systems as large as three thousand (3,000) horsepower.
Yet another advantage of this invention is to de-water and purify oils and other liquids, utilizing one or more of the modular components of this invention in various sizes for liquid storage tanks as small as one (1) gallon to liquid storage tanks as large as one million (1,000,000) gallons.
Starting out from the known prior art, it is the task to be solved by the present invention to drastically simplify the design and construction of the apparatus and add more uses to the apparatus while maintaining all of the advantages such that the production costs of the apparatus as well can be drastically decreased.
Other and further objects and advantages of the invention will become obvious to those skilled in the art upon a review of the following description of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a perspective front view of the water/separator module used in a contaminate removing system using a separator tube of a first variant;
FIG. 2 illustrates a perspective front view of the helix coalescer of the separator tube of FIG. 1 ;
FIG. 3 is a perspective bottom view of the upper end cap of the water/separator module used in a contaminate removing system;
FIG. 4 illustrates a partial sectional front view of the water/separator module used in a contaminate removing system using a separator tube of a second variant;
FIG. 5 illustrates a perspective side view of the separator tube of the water/separator module of FIG. 4 ;
FIG. 6 illustrates a perspective front view of the a filter cartridge of the filter module used in a contaminate removing system;
FIG. 7 is a perspective bottom view of the upper end cap of the filter module used in a contaminate removing system;
FIG. 8 illustrates a perspective side view of the filter module assembled in concert with the separator module used in a contaminate removing system;
FIG. 9 illustrates a perspective front view of the water/separator module assembled in concert with the pump module and the filter module used in a contaminate removing system;
FIG. 10 illustrates a flow diagram of the contaminate removing system that re-circulates fluids; and
FIGS. 11-17 illustrate flow diagrams of the present contaminate removing system that supply an engine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Now referring to the drawings there is shown a water/separator module 1 in accordance with the invention. FIG. 1 illustrates a perspective front view of a water/separator module including an upper end cap 2 and a bottom end cap 6 . An outer tubular body 4 is held between the upper end cap 2 and the bottom end cap 6 by use of a tie rod 71 , shown in FIG. 4 , which is secured by a tightening nut 70 . The outer tubular body can be made of clear plastic or metal. The tubular body 4 is provided with seals on the upper and lower ends thereof to prevent any leakage between the ends of the tubular body and the upper and bottom end caps 2 , 6 , respectively. Referring also to FIG. 3 , it can be seen that an axially aligned separator tube 3 extends downward from the upper end cap 2 and is confined by a threaded circular portion 27 of the upper end cap which surrounds an inlet opening 26 in the upper end cap 2 and connects to an outlet port 21 . The upper end cap has a connecting flange 19 which surrounds the outlet port 21 . The outlet port 20 is provided with a circular o-ring seal face 22 to prevent leakage when attached to another flange, to be described hereinafter. The flange 19 has a plurality of mounting holes to facilitate attachment to similar flanges on other modular components of this invention, to be described hereinafter. The upper end cap 2 is made from a metal, plastic, or composite casting or die casting as with the inlet port that connects to a helix shape groove that directs fluid in a circular and downward direction.
The lower end of the separator tube 3 surrounds a threaded inner flange 33 (shown in hidden lines) of a vortex finder 5 which is also provided with an outer flange 35 . A helix coalescer plate inside the axially aligned tube extends downward from the upper end cap to the inside flange on the vortex finder. The vortex finder is provided with the outer flange to create vortices in the downward flowing fluid. An air inlet valve 29 is provided at the top of the upper end cap 2 and a drain port 38 and drain valve 76 is provided in the lower end cap 6 . The upper and lower end caps can be equipped with an optional water sensor probe, electric heating element, or fluid heat exchanger. The contaminant holding capacity of any size water/separator module can be increased by simply increasing the length of the outer tubular body.
The bottom end cap 6 is provided with the threaded drain port 38 to which the drain valve 76 is attached. The bottom end cap 6 is held in place with the tie rod 71 which extends through hole 39 in the bottom end cap 6 to a threaded hole 24 provided in the upper end cap. A tightening nut 70 , secured the bottom end cap to the tubular body 4 , and a washer and a seal are provided therebetween to prevent any leakage around the tie rod.
FIG. 2 illustrates a perspective front view of the a helix coalescer 30 which is disposed in the separator tube 3 according to a first variant shown in FIG. 1 , to create vortices containing contaminants that will collide and grow in size. The larger droplets will overcome the upward flow of the fluid (Stokes Law) in the separator tube 3 and fall to the bottom of the bottom end cap 6 .
In operation of the water/separator module FIG. 1 , the contaminated fluid is moved into the inlet port 25 of the upper end cap 2 and to a helix groove 28 disposed in the upper end cap 2 . In the helix groove 28 , the heaver fluid and contaminates are rotated to the outside of the outer tubular body 4 by centrifugal force and are rotated in a downward circular motion until approximately 90% of the contaminate have coalesced and settled to the bottom of the end cap 6 . The fluid containing the smallest contaminate droplets is carried upward in a circular motion through the vortex finder 5 into the separator tube 3 , where vortices form as they pass over the helix coalescer 30 . The vortices cause the contaminant droplets to collide, coalesce, and fall to the bottom of end cap 6 . To drain the water/separator module of water and contaminates, the air inlet valve 75 is opened and the drain valve 76 is opened.
FIGS. 4 and 5 illustrates the water/separator module 1 used in a contaminate removing system and a separator tube 67 of a second variant. The separator tube 67 is attached to the upper end cap 2 as described with reference to FIG. 1 . The helix coalescer 35 , here embodied with dual helix flutes, is disposed on the outside of the separator tube 67 . A conical circular plate 5 is mounted to the tie rod 71 . A sensor probe 77 is mounted to the end cap 6 and extends into the tubular body 4 for taking measurements as desired.
The upper end caps inlet port connects to the helix shape groove 28 that directs fluid in a circular and downward direction. As the droplets of water are forced to the outside of the helix groove 28 they begin to coalesce. The axially aligned tube 67 with dual helix flutes of the coalescer 35 that extend outward from the tube and that extend downward from the upper end cap 2 cause the water droplets to continue to coalesce as they flow downward. The enlarged droplets of water and other matter that has a specific gravity greater than the fluid spirals to the bottom of the separator. The smallest water droplets flow upward through the inside of the axially aligned tube. As the smallest droplets pass the circular plate baffle 5 located inside the axially aligned tube 67 vortices are formed causing the droplets to coalesce and grow in size. When the droplet size is large enough to overcome the upward flow of the fluid, (Stokes Law), they will drop to the bottom of the separator.
The upper and lower end caps can be equipped with an optional water sensor probe, electric heating element, or fluid heat exchanger. The contaminant holding capacity of any size water/separator module can be increased by simply increasing the length of the outer tubular body.
FIGS. 6 and 7 show the elements of the filter module including filter cartridge 9 , an upper end cap 8 , and outlet port 41 . Inlet port 47 is connected to an outlet opening 45 that will let contaminated fluid pass to the inlets 52 of spin on filter cartridge 9 . Spin on filter 9 is attached to the upper end cap 8 with an axial nipple 43 which connects to the outlet port 41 on the upper cap 8 and the filters outlet port 51 . The filter is provided with a seal 53 that is in contact with a surface 42 on upper end cap 8 to prevent leakage of fluid. The upper end cap 8 has a connecting flange 46 which surrounds the inlet port 47 which is provided with a circular o-ring seal face 48 to prevent leakage when attached to another flange. The flange 46 has a plurality of mounting holes 50 to facilitate attachment to similar flanges on other modular components of this invention.
In operation of the present filter module, contaminated fluid enters port 47 , and flows to outlet chamber 45 and into the top of filter 9 through a plurality of equally spaced inlet apertures 52 , where filter media removes particulate matter and other contaminates. The fluid then flows up through outlet port 51 into inlet port 44 which is connected to outlet port 41 . Outlet port 49 is plugged. However if the filter module is used in concert with a pump module then outlet port 41 is plugged and the fluid flows through outlet port 49 . The filter module can be used with a wide variety of spin on filters with different capacities, flow rates, filter media and configurations.
The preferred filter module of the above defined kind is made from a metal, plastic, or composite casting or die casting as an upper end cap with an inlet port that connects to a channel through which the fluid enters and is directed downward through an outlet port and into the upper area of a spin-on filter. The spin-on filter is secured to the upper end cap by the threaded axial nipple that connects with the two outlet ports.
One of the outlet ports will be plugged to direct the flow of the fluid to the other outlet port. The upper end cap has a connecting flange which surrounds one of the outlet ports and is provided with an o-ring groove and a plurality of equally spaced bolt holes to connect the filter module to a mounting bracket and/or other modules of the apparatus. The filter modules can be used with commercially manufactured spin-on filters of various sizes and media down to one (1) micron.
FIG. 8 illustrates a perspective side view of the present filter module assembled in concert with the present separator module used in a contaminate removing system. In operation the contaminated fluid enters inlet port 25 of the water/separator module where water and other contaminates are removed. The fluid passes through outlet port 21 , FIG. 3 and into inlet port 47 , FIG. 7 of the filter module where filter media removes particulate matter and other contaminates. The purified fluid then flows out of outlet port 41 . This combination of separation and filtration modules can be used on engine fuel systems as well as other uses.
Seen in FIG. 9 is a perspective front view of a pump housing 11 . The pump housing 11 provides a plurality of mounting holes for the attachment of the water/separator, filter, and control modular components of this invention. Fluid lines are routed through ports to connect the pump 18 to the inlets and outlets of connected components. A port is also provided for routing an electrical feed cable. The pump 18 is disposed in the pump housing can be attached thereto by threaded holes. A plurality of threaded holes 58 are provided to attach a cover of the pump housing 11 . A pump housing cover contains a plurality of holes to attach the cover to the pump housing and mount switches, a timer, and any other controls necessary for operating a pump, etc.
The preferred pump module of the above defined kind is made from a metal, plastic, or composite casting or die casting as a pump mounting box with ports and a plurality of equally spaced bolt holes to connect a filter module, water/separator, and/or mounting bracket with matching equally spaced holes. The pump module cover may contain a control module that will start and stop the pump, detect the presents of water in a system, time a pumping duration and start/stop time, sound an alarm, activate a contaminate removal system, or shut down an engine.
FIG. 9 illustrates a perspective front view of the water/separator module 1 assembled in concert with the pump module 14 and the filter module 7 used in a contaminate removing system where the operation is similar to U.S. Pat. No. 6,042,722. Contaminated fluid is drawn from a bottom of a tank and passed into the separator module 1 . The water and contaminate stays at the bottom of the separator and is drained off. The fluid is passed through a filter module 7 by means of the pump module 14 . The pump module 14 draws contaminated fluid into the filter module 1 . The filter module 7 removes any particles of matter and then the fluid is directed back to the tanks or on to an engine. The process can be repeated for as many times as necessary to cleanse the fluid of water and contaminates.
FIGS. 10 through 17 depict in simplified diagrams the various embodiments of the contaminate removing system, according to the invention.
FIG. 10 is a flow chart depicting the fluid flow from a fluid tank 67 to the separator module 1 through the present filter module 7 to the present pump module 12 . Then the fluid is recycled back to a fluid tank 67 .
FIG. 11 is a flow chart depicting the fluid flow from a fluid tank 67 to the separator module 1 to the present pump module 12 and then on to an engine.
FIG. 12 is a flow chart depicting the fluid flow from a fluid tank 67 through the filter module 7 to the present pump module 12 and then on to an engine 68 .
FIG. 13 is a flow chart depicting the fluid flow from a fluid tank 67 to an engine with the pump module transferring fluid from fluid tank 69 to the fluid tank 67 .
FIG. 14 is a flow chart depicting the fluid flow from a fluid tank 67 to the separator module 1 through the present filter module 7 to the present pump module 12 and then on to the engine 68 .
FIG. 15 is a flow chart depicting the fluid flow from a fluid tank 67 to the separator module 1 through the present filter module 7 then on to the engine 68 .
FIG. 16 is a flow chart depicting the fluid flow from a fluid tank 67 to the separator module 1 then on to the engine 68 .
FIG. 17 is a flow chart depicting the fluid flow from a fluid tank 67 to the filter module 7 then on to the engine 68 .
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This invention relates to the removal by centrifugal force and by coalescence of water and other impurities from diesel fuel, jet fuel, gasoline, kerosene, bio-diesel fuel, ethanol enriched fuel, heating oil, hydraulic oil, cutting oils, and other liquids with a specific gravity of less than one. The invention provides a contaminate removing apparatus, in particular for de-watering and purifying fuel liquids, comprising modular components consisting of but not limited to a water-separator module, a filter module, a pump module, and a control module to be used in plurality or as standalone components to de-water and purify fuel oils and other liquids.
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FIELD
[0001] The present disclosure relates to automatic transmissions and more particularly to fluid expansion reservoirs for automatic transmissions.
BACKGROUND
[0002] The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
[0003] Motor vehicle automatic transmissions must and do provide both reliable torque multiplication and torque and speed matching over a wide range of both ambient and operating temperatures. The operating temperature of an automatic transmission may be considered to range from cold, i.e., a winter morning start, through warm, i.e., normal operation, to hot, i.e., maximum operating temperature. The fluid within a transmission, commonly referred to as “automatic transmission fluid” or ATF, contracts when it is cold and expands when it is hot. Thus, the noted temperature limits correspond to the minimum and maximum volumes of transmission fluid for a given mass of transmission fluid.
[0004] The minimum design or start up temperature dictates the minimum mass of transmission fluid required in the transmission. Under this operating condition, the transmission fluid is most dense which reduces the volume of transmission fluid within the transmission sump and transmission and the viscosity of the fluid is at a maximum thereby further reducing sump and transmission fluid volume due to fluid coating or adhering to transmission components and surfaces.
[0005] The maximum design or operating temperature dictates the maximum transmission sump fluid volume which maintains a fluid level below the rotating components of the transmission. If the transmission fluid contacts the rotating components, the fluid will become foamy with entrained air which increases frictional drag and adds heat to the transmission fluid. Eventually, the entrained air will interfere with the action of the transmission pump, transmission fluid pressure will drop, forcing a transmission shutdown and possibly causing damage to the transmission.
[0006] It is therefore apparent that the automatic transmission and transmission fluid cooling system must accommodate the cold and, more significantly, the hot volume of transmission fluid, while maintaining intended and desired vehicle performance. This requirement, in addition to the requirements of various vehicle ride heights, suspension components and various engine configurations have proliferated the number of transmission oil (ATF) pans and filter/pump pickups for the same model of automatic transmission.
[0007] The present invention is directed to an apparatus for accommodating the volume change of transmission fluid from cold to hot while maintaining proper transmission sump and operating levels.
SUMMARY
[0008] The present invention provides an active fluid reservoir for the transmission fluid of an automatic transmission. In a first embodiment, the fluid reservoir comprehends an elongate reservoir disposed adjacent and parallel to fluid lines leading from the automatic transmission to the transmission oil (fluid) cooler (TOO). Depending upon available space, the reservoir may be a single, larger reservoir associated with either the supply or return line or two smaller reservoirs associated with both lines. Thermally actuated valves at each end of the reservoir(s) open to allow fluid flow through the reservoir as fluid temperature increases and a diverter valve in the cooler line(s) closes to divert flow into the reservoir. In a second embodiment, the fluid reservoir comprehends a container, tank or similar storage device in fluid communication with a transmission oil cooler (TOO) line. Again, the device includes thermally actuated valves which open to provide fluid flow from the oil cooler line to the reservoir and a diverter valve in the oil cooler line which closes upon a temperature increase to divert flow to the reservoir. In both embodiments, the reservoir must be located above the transmission sump to that the transmission fluid returns by gravity to the sump when the engine and transmission are not operating.
[0009] It is thus an aspect of the present invention to provide an active transmission fluid reservoir for automatic transmissions.
[0010] It is a further aspect of the present invention to provide a transmission fluid reservoir having a pair of thermally actuated flow valves and a thermally actuated diverter valve.
[0011] It is a still further aspect of the present invention to provide a transmission fluid reservoir having at least one elongate reservoir disposed along a transmission oil cooler line.
[0012] It is a still further aspect of the present invention to provide a transmission fluid reservoir having at least one elongate reservoir disposed along a transmission oil cooler line, a pair of flow controlling valves and a diverter valve.
[0013] It is a still further aspect of the present invention to provide a transmission fluid reservoir having at least one elongate reservoir disposed along a transmission oil cooler line, a pair of thermally actuated flow controlling valves and a thermally actuated diverter valve.
[0014] It is a still further aspect of the present invention to provide a transmission fluid reservoir having a pair of elongate reservoirs disposed along a respective pair of transmission oil cooler lines.
[0015] It is a still further aspect of the present invention to provide a transmission fluid reservoir having a storage container.
[0016] It is a still further aspect of the present invention to provide a transmission fluid reservoir having a storage container, a pair of flow controlling valves and a diverter valve.
[0017] It is a still further aspect of the present invention to provide a transmission fluid reservoir having a storage container, a pair of thermally actuated flow controlling valves and a thermally actuated diverter valve.
[0018] Further aspects, advantages and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
[0019] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
[0020] FIG. 1 is a schematic diagram of a portion of an exemplary motor vehicle powertrain having a radiator, an engine and a transmission and incorporating the present invention;
[0021] FIG. 2 is a diagrammatic view of a first embodiment of a transmission fluid reservoir according to the present invention in a cold or low temperature operating state or condition;
[0022] FIG. 3 is a diagrammatic view of a first embodiment of a transmission fluid reservoir according to the present invention in a hot or high temperature operating state or condition;
[0023] FIG. 4 is a diagrammatic view of a second embodiment of a transmission fluid reservoir according to the present invention in a cold or low temperature operating state or condition; and
[0024] FIG. 5 is a diagrammatic view of a second embodiment of a transmission fluid reservoir according to the present invention in a hot or high temperature operating state or condition;
DETAILED DESCRIPTION
[0025] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
[0026] With reference to FIG. 1 , a portion of a motor vehicle powertrain incorporating the present invention is illustrated and generally designated by the reference number 10 . The illustrated powertrain 10 includes a radiator 12 which is in fluid communication with an engine 14 which may be a gas, Diesel or flex fuel engine. The output of the engine 14 is coupled to the input of a transmission 16 . The transmission includes a fluid sump 18 into which transmission fluid flows under the influence of gravity and is collected. The transmission 16 also includes an output shaft 20 which drives a final drive assembly (FDA) 22 which may include, for example, a prop shaft, a differential, axles and tires and wheels (all not illustrated).
[0027] The radiator 12 includes a transmission oil (fluid) cooler 24 disposed therewithin. The transmission oil cooler 24 is in fluid communication with the transmission 16 through a pair of fluid lines, pipes or hoses 26 and 28 , one of which ( 26 ) functions as a supply line of hotter fluid from the transmission 16 to the transmission oil cooler 24 in the radiator 12 and the other of which ( 28 ) functions as a return line of cooler fluid from the transmission oil cooler 24 to the transmission 16 .
[0028] Disposed in one of the fluid lines, pipes or hoses, preferably the supply line 26 , is an active transmission fluid expansion reservoir assembly 30 . At the outset, it should be noted that the transmission fluid expansion reservoir assembly 30 must be disposed generally above the level of the sump 18 of the transmission 16 such that when the engine 14 and transmission 16 are not operating, fluid which has accumulated in the transmission fluid expansion reservoir assembly 30 will return to the sump 18 under the influence of gravity.
[0029] Turning now to FIGS. 2 and 3 , a first embodiment of an active transmission fluid expansion reservoir assembly 30 is illustrated in fluid communication with the transmission oil cooler supply line 26 . The transmission fluid expansion reservoir assembly 30 is an in-line, cylindrical assembly and typically occupies an axial distance of several inches along the length of and parallel to the cooler supply line 26 . If packaging and space limitations do not permit such a configuration, multiple, smaller reservoir assemblies may be utilized, for example, one on each of the supply and return lines 26 and 28 .
[0030] Disposed within the cooler supply line 26 is a first or diverter valve 32 which is capable of substantially fully opening and fully closing the flow path through the cooler supply line 26 . The first or diverter valve 32 preferably comprehends a circular disc 34 or similar valve structure such as a ball valve that is opened and closed through 90 degrees of rotation. Other valve configurations such as a sliding valve, a poppet valve or an iris valve—the common feature of such valves being their full opening and closing with relatively limited input motion—may also be utilized here and at the other valve locations. The circular disc 34 is secured to a shaft or rod 36 that is supported by the wall of the cooler supply line 26 or other suitable structure and is coupled to a bi-metallic operator 38 . As the temperature of the transmission oil in the cooler supply line 26 increases, the bi-metallic operator 38 rotates the circular disc 34 from the position illustrated in FIG. 2 which allows unrestricted fluid flow of transmission oil through the cooler supply line 26 to the position illustrated in FIG. 3 which closes off the cooler supply line 26 and inhibits flow therethrough. Alternatively, the bi-metallic operator 38 may be replaced by an operator utilizing the thermal expansion of a fluid. Additionally, it should be appreciated that the circular disc 34 (or other valve configuration) may be coupled to and rotated by an electric, hydraulic or pneumatic actuator controlled by a signal from a temperature sensor such as a thermistor located, for example within the transmission 16 .
[0031] The in-line transmission fluid expansion reservoir assembly 30 also includes a reservoir 40 that preferably extends axially along one side of the cooler supply line 26 . Alternatively, the reservoir 40 may be concentrically disposed about the cooler supply line 26 as indicated by the dashed reference line 42 . At the upstream end of the reservoir 40 , between the cooler supply line 26 and the reservoir 40 , is disposed a second or inlet valve 44 . The second or inlet valve 44 may be of construction similar to that of the first or diverter valve 32 . Thus, it may include a circular disc 46 that is attached to a shaft 48 that is rotated by a bi-metal operator 52 . At the downstream end of the reservoir 40 , between the cooler supply line 26 and the reservoir 40 , is disposed a third or outlet valve 54 . The third or outlet valve 54 may also be of construction similar to that of the first or diverter valve 32 . Thus it may include a circular disc 56 that is attached to a shaft 58 that is rotated by a bi-metal operator 62 .
[0032] The second or inlet valve 44 and the third or outlet valve 54 operate in unison but in opposition to the first or diverter valve 32 . That is, as the temperature of the transmission fluid increases, the bi-metallic operators 52 and 62 rotate the second or inlet valve 44 and the third or outlet valve 54 , respectively, from the closed positions illustrated in FIG. 2 to the open positions illustrated in FIG. 3 . Thus, as the second or inlet valve 44 and the third or outlet valve 54 open, the first or diverter valve 32 closes. Once again, it should be appreciated that all three valves 32 , 44 and 54 may be controlled by one or more electric, hydraulic or pneumatic operators controlled by a signal from temperature sensor located, for example, within the transmission 16 .
[0033] Accordingly, during operation of the engine 14 and the transmission 16 , as the temperature of the transmission fluid increases, the diverter valve 32 closes and the inlet valve 44 and the outlet valve 54 open, providing the additional volume of the reservoir 40 to the fluid circuit which accommodates the temperature related expansion of the transmission fluid. When the engine 14 is shut off and the transmission fluid and the transmission 16 cool down, the diverter valve 32 re-opens and the inlet valve 44 and the outlet valve 54 close. As this is occurring, the transmission fluid is also contracting and, before the outlet valve 54 fully closes, the transmission fluid which has accumulated in the reservoir 40 flows into the sump 18 of the transmission 16 under the influence of gravity.
[0034] Referring now to FIGS. 4 and 5 , a second embodiment of an active transmission fluid expansion reservoir assembly 70 employing a container or tank as the fluid reservoir is illustrated in conjunction with the transmission oil cooler supply line 26 . The transmission fluid expansion reservoir assembly 70 includes a container or tank 72 which may be located at any convenient location above the level of the sump 18 of the transmission 16 and mounted to any convenient under-hood component such as the radiator 12 , the engine 14 or the transmission 16 . The container or tank 72 includes an inlet line or tube 74 in fluid communication with the transmission oil cooler supply line 26 and an outlet line or tube 76 also in fluid communication with the transmission oil cooler supply line 26 .
[0035] Disposed within the transmission oil cooler supply line 26 is a first or diverter valve 82 which is capable of substantially fully opening and fully closing the flow path through the cooler supply line 26 . The first or diverter valve 82 preferably comprehends a circular disc 84 or similar valve structure that is opened and closed through 90 degrees of rotation. The circular disc 84 is secured to a shaft or rod 86 that is supported by the wall of the cooler supply line 26 or other suitable structure and is coupled to a bi-metallic operator 88 . As the temperature of the transmission oil in the cooler supply line 26 increases, the bi-metallic operator 88 rotates the circular disc 84 from the open position illustrated in FIG. 4 which allows unrestricted fluid flow of transmission oil through the cooler supply line 26 to the closed position illustrated in FIG. 5 which closes off the cooler supply line 26 and inhibits flow therethrough. Again, it should be appreciated that the circular disc 84 may be coupled to and rotated by an electric, hydraulic or pneumatic actuator controlled by a signal from a temperature sensor located, for example, within the transmission 16 .
[0036] At the juncture of the inlet line or tube 74 and the transmission oil cooler supply line 26 , the tank type transmission fluid expansion reservoir assembly 70 includes a second or inlet valve 92 . The second or inlet valve 92 may be of construction similar to that of the first or diverter valve 82 . Thus it may include a circular disc 94 that is attached to a shaft 96 that is rotated by a bi-metal operator 98 . At the juncture of the outlet line or tube 76 and the cooler supply line 26 , is a third or outlet valve 102 . The third or outlet valve 102 may also be of construction similar to that of the first or diverter valve 82 . Thus it may include a circular disc 104 that is attached to a shaft 106 that is rotated by a bi-metal operator 108 .
[0037] The second or inlet valve 92 and the third or outlet valve 102 operate in unison but in opposition to the first or diverter vale 82 . That is, as the temperature of the transmission fluid increases, the bi-metallic operators 88 and 108 respectively rotate the second or inlet valve 92 and the third or outlet valve 102 from the closed positions illustrated in FIG. 4 to the open positions illustrated in FIG. 5 . Thus, as the second or inlet valve 92 and the third or outlet valve 102 open, the first or diverter valve 82 closes. Once again, it should be appreciated that all three valves 82 , 92 and 102 may be controlled by one or more electric, hydraulic or pneumatic operators controlled by a signal from temperature sensor located, for example within the transmission 16 .
[0038] Accordingly, during operation of the engine 14 and the transmission 16 , as the temperature of the transmission fluid increases, the diverter valve 82 closes and the inlet valve 92 and the outlet valve 102 open, providing the additional volume of the container or tank 72 to the hydraulic circuit which accommodates the temperature related expansion of the transmission fluid. When the engine 14 is shut off and the transmission fluid and the transmission 16 cool down, the diverter valve 82 re-opens and the inlet valve 92 and the outlet valve 102 close. As this is occurring, the transmission fluid is also contracting and, before the outlet valve 102 fully closes, the transmission fluid which has accumulated in the container or tank 72 flows into the sump 18 of the transmission 16 under the influence of gravity.
[0039] The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
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An active fluid reservoir for transmission fluid of an automatic transmission, in a first embodiment, comprehends an elongate reservoir disposed adjacent and parallel to fluid lines leading from the automatic transmission to the transmission oil (fluid) cooler (TOC). Depending upon available space, the reservoir may be associated with either the supply or return line or two smaller reservoirs associated with both lines. Thermally actuated valves at each end of the reservoir(s) open to allow fluid flow through the reservoir as fluid temperature increases and a diverter valve in the cooler line(s) closes to divert flow into the reservoir. In a second embodiment, the fluid reservoir comprehends a container, tank or similar storage device in fluid communication with a transmission oil cooler (TOC) line. Again, the device includes thermally actuated valves which open to provide fluid flow from the oil cooler line to the reservoir and a diverter valve in the oil cooler line which closes upon a temperature increase to divert flow to the reservoir.
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FIELD OF THE INVENTION
The invention relates to a novel catalyst and process for producing various chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons. The catalyst of the invention is prepared by co-extruding aluminum/chromium oxide and optionally impregnating the aluminum/chromium oxide support with a metal halide. The chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons produced using the catalyst of the invention are useful in a variety of industrial applications including blowing agent, refrigerant, sterilant gas and solvent applications.
BACKGROUND OF THE INVENTION
Although chlorofluorocarbons (CFCs), like trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) and chloropentafluoroethane (CFC-115) have a variety of industrial and household applications including refrigerant, solvent and blowing agent applications, they may be deleterious to the earth's protective ozone layer. Because of the potential destruction of atmospheric ozone by CFCs, there is a great need to develop substitutes for these compounds which function in substantially the same way as the CFCs but are low or zero ozone depleting. Several such replacement materials include 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123), 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), pentafluoroethane (HFC-125) and 1,1,1,2-tetrafluoroethane (HFC-134a). Because the demand for these and others low or zero ozone depleting materials will increase dramatically in the future, commercially viable processes for the preparation of these materials are needed.
Several methods for the production of hydrochlorofluorocarbons and hydrofluorocarbons are reported in the prior art. These methods, however, are not without their shortcomings. Many of these known processes utilize catalysts which are not very selective and, as a result, produce the desired hydrochlorofluorocarbons or hydrofluorocarbon along with a host of other by-products thus reducing the yield of the desired product. Some of these catalysts are hindered by their very short life span which makes them impractical for commercial production. The operating conditions described in the art also make many of the known processes for the production of hydrochlorofluorocarbons and hydrofluorocarbons impractical for commercial production. Among the prior art processes, the following are typical. Except where otherwise indicated, the term "combined 120's" as used herein shall refer to the combined selectivities of chlorofluorocarbons and/or hydrochlorofluorocarbons and/or hydrofluorocarbons produced in a given hydrofluorination reaction.
U.S. pat. No. 3,755,477 to Imperial Chemical Industries Ltd. describes a process for producing fluorinated aliphatic hydrocarbons which comprises fluorinating a halogenated hydrocarbon, including tetrachloroethylene, by reaction in the gas phase with HF in the presence of a steam-treated and calcined chromium oxide catalyst prepared by a multi-step process. The process of the invention as exemplified by Example 23 reports a selectivity for combined 120's of only 70% while producing a substantial amount of the less desired chloropentafluoroethane.
U.S. Pat. No. 3,258,500 to DuPont describes a process for the catalytic vapor phase reaction of HF with halohydrocarbons, including tetrachloroethylene, employing a catalyst that consists essentially of a heat-activated anhydrous chromium (III) oxide which may be supported on alumina. The reference also discloses that catalysts, in the form of activated chromium (III) oxide admixed with aluminum oxide may be used in the process of the invention. The catalyst is prepared by co-precipitation. Like the above-described process, this process exhibits a selectivity for combined 120's of only 73.7%. The remaining almost 26% was unaccounted for (and presumably was waste). See Example 17.
GB 1,000,485 to Scipioni et al., describes a process for the preparation of organic fluorinated compounds by fluorination of halo-olefins in the gaseous phase. The catalyst consists essentially of partially fluorinated alumina impregnated with one or more polyvalent metal halides. The polyvalent metal may be chromium, cobalt, nickel or manganese. The total content of polyvalent metal halide, expressed as oxide, is not more than 15% by weight of the partially fluorinated (70-80%) alumina. Example 4 (Table 4) shows that reaction of tetrachloroethylene with HF over said catalyst yields dichlorotrifluoroethane as the major product. The patent also provides that if fluorination of the catalyst is excessive, the activity of the catalyst is impaired.
U.S. Pat. No. 4,843,181 to DuPont describes a gas-phase process for the manufacture of 1,1,1-trifluorodichloroethane and/or 1,1,1,2-tetrafluoroethane by contacting a suitable tetrahaloethylene, including tetrachloroethylene, and/or pentahaloethane with HF in the presence of Cr 2 O 3 prepared by pyrolysis of (NH 4 ) 2 Cr 2 O 7 . In order to obtain the desired product in high yield, this process requires a long contact time (i.e., 90 seconds) between the catalyst and reactants making the process impractical for commercial operation.
U.S. Pat. No. 4,967,023 to Ausimont discloses a process for preparing 1,1,1-trifluoro-2,2-dichloroethane by hydrofluorination, in the gas phase, of perchloroethylene in the presence of a catalyst comprising chromium oxide supported on AlF3 in the gamma and/or beta form. This process suffers from low conversion of the reactants resulting in low productivity of 1,1,1-trifluoro-2,2-dichloroethane.
Kokai Patent Publication No. 178237 Published Jul. 11, 1990, discloses a method of making 1,1,2-trichloro-2,2-difluoroethane, 1,1-dichloro-2,2,2-trifluoroethane, 1-chloro-1,2,2,2-tetrafluoroethane and pentafluoroethane by fluorinating perchloroethylene in the gas phase with HF in the presence of a fluorination catalyst which consists of an oxide containing Cr and at least one element selected from the group of Al, Mg, Ca, Ba, Sr, Fe, Ni, Co and Mn. The catalyst is prepared by co-precipitation.
It is a particular object of the invention to provide a catalyst which is useful in the production of chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons.
It is another object of the invention to provide a catalyst with a high productivity.
It is another object of the invention to provide a catalyst which is highly active.
It is another object of the invention to provide a catalyst which has a long life.
Still another object of the invention is to provide a catalyst which can be easily regenerated.
Other objects and advantages of the invention will become apparant from the following description.
SUMMARY OF THE INVENTION
The invention relates to a novel catalyst and process for preparing a desired chlorofluorocarbon, hydrochlorofluorocarbon or hydrofluorocarbon said catalyst comprising a mixture of aluminum and chromium oxide and optionally a metal salt and prepared by the co-extrusion of aluminum oxide hydroxide with chromium oxide and optionally impregnation with a metal salt.
The chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons produced by this process may be used in a variety of industrial applications including solvent, refrigerant, sterilant gas and blowing agent applications.
DETAILED DESCRIPTION OF THE INVENTION
The invention relates to a novel catalyst and process for the hydrofluorination of a halogenated aliphatic hydrocarbon to produce a chlorofluorocarbon, hydrochlorofluorocarbon or hydrofluorocarbon. A key feature of the invention is that through catalyst selection and preparation, the desired product, can be obtained as the major product at high productivity, normally greater than 10 lbs/hr/ft 3 . In addition, because of the catalyst's high selectivity, only small amounts of nonrecyclable by-products are formed (i.e., usually less than 5%).
The catalyst of the invention is prepared by the co-extrusion of aluminum oxide hydroxide and chromium oxide and optionally the impregnation of a metal salt followed by calcination at high temperature in air. Specifically, the aluminum oxide hydroxide and chromium oxide particles are kneaded into a thick paste in a solvent such as water, alcohol or dilute mineral acid. Dilute nitric acid (i.e., about 6 wt. % solution) and water are preferred. The amount of solvent used is not critical. Preferably, the amount of solvent should be adjusted so that the extrudate has a mimimum crush strength of greater than about 2 lbs. Crush strength may be determined using any of the techniques well known in the art. It may be determined, for example, using the Flat Plate Side Crush Strength Method.
The mixture is then extruded and preferably calcined. The conditions for extrusion, including temperature, pressure, the size of the extruder, the die size and extrusion rate are not critical. For example, the extruder may be General Electrics's Brabender Model 100, the die may be a 1/16 inch single hole die, the rate of extrusion may be from about 2 to about 10 lbs/hr and the extrusion may be conducted at room temperature and zero pressure.
Optionally, the aluminum/chromium oxide support may be impregnated with a metal salt. If this is done, then Prior to impregnation, the extruded aluminum/chromium oxide support is calcined. Metal salts useful in the invention include metal halides such as cobalt, nickel, manganese, rhodium and ruthenium halide. Chlorine is the preferred halide. Following impregnation, the catalyst is dried and may be calcined.
The chromium (III) oxide may be crystalline chromium oxide or amorphous chromium oxide having a preferred median particle size of less than 100 microns, more preferably less than 70 microns and most preferably, less than 50 microns.
The aluminum oxide hydroxide preferably has a median particle size of less than 100 microns, more preferably, less than 50 microns and most preferably less than 30 microns.
Chromium (III) oxide and aluminum oxide hydroxide are commercially available materials which may be Purchased in a variety of particle sizes. Chromium (III) oxide may be purchased, for example, from Great Western Inorganics of Golden, Colorado while aluminum oxide hydroxide is available, for example, through Vista Chemical Inc.
The preferred mole ratio of aluminum:chromium oxide is from about 95:5 to about 5:95, more preferably from about 85:15 to about 40:60 and most preferably from about 80:20 to about 50:50. When a metal salt is used, the preferred loading of the metal salt is from about 0.1 to about 20 wt. % of the mixed oxide support, more preferably from about 0.3 to about 10 wt. % of the mixed oxide support and most Preferably from about 0.5 to about 5 wt. % of the mixed oxide support.
Impregnation of the mixed oxide support with a metal salt may be accomplished by any means well known in the art. For example, impregnation may be accomplished in accordance with step (b) of Example 1 discussed below.
Calcination conditions after extrusion are important to catalyst activity. Calcination can be conducted in an uncontrolled atmosphere of stagnant air or in a controlled continuous flow of air or inert atmosphere. Preferably calcination is accomplished at a temperature of from about 200° to about 800° C., more preferably from about 300° to about 600° C. and most preferably from about 350° to about 500° C. resulting in a catalyst with a high surface area.
Preferably, the resulting product is pretreated with HF before use. It is thought that this converts some of the surface aluminum oxide to aluminum fluoride and/or aluminum oxy-fluoride and converts some of the surface chromium oxide to chromium oxy-fluoride. This pretreatment can be accomplished by passing an excess of HF over the catalyst at an initial temperature of 200° C. The exotherm generated by this step may be controlled by using air or an inert gas as diluent for the HF. After the exotherm disappears, pure HF can be used. At this point, the temperature is raised to at least about 300° C. and the catalyst is maintained at this temperature for from about 2 to about 8 hours.
The catalyst of the invention has a life of more than 1800 hours with periodic regeneration. Catalyst activity or catalyst life can be maintained without regeneration by cofeeding air or oxygen to the reactor. The amount of air or oxygen supplied to the reactor is preferably controlled at from about 0.01 to about 30 mole % of oxygen or air relative to the total organics fed to the reactor, more preferably from about 0.05 to about 20 mole % and most preferably from about 0.1 to about 10 mole %. Otherwise, periodic regeneration may be easily accomplished, for example, by repeating the procedure described in Example 1(c) below.
Generally, the process embodiment of the invention is as follows.
In a process for preparing a desired chlorofluorocarbon, hydrochlorofluorocarbon or hydrofluorocarbon wherein a halogenated aliphatic hydrocarbon is reacted with anhydrous hydrogen fluoride in the presence of a catalyst comprising a mixture of partially fluorinated aluminum and chromium oxide and optionally a metal salt, the improvement comprises:
(a.) preparing said catalyst by blending aluminum oxide hydroxide and chromium oxide together in the presence of a solvent, extruding the blend and optionally impregnating the blend with a metal salt.
The degree to which the catalyst is fluorinated is not critical. Significant catalytic activity results when the catalyst is at least 5% fluorinated and Preferably not more than 90% fluorinated. Fluorination in excess of 90% may result in catalyst deactivation.
Preferably, the halogenated aliphatic hydrocarbon contains between two and six carbon atoms and more preferably contains between two and three carbon atoms.
Most preferably, the halogenated hydrocarbon is selected from the group consisting of C 2 H x Cl 4-x-y F y , wherein x=0 to 1 and y=0 to 3, C 2 H x Cl 6-x-y F y , wherein x=0 to 2 and y=0 to 4 and mixtures thereof and includes trihaloethylenes like trichloroethylene, tetrahaloethylenes such as perchloroethylene, 1-fluoro-1,2,2-trichloroethylene, 1,1-difluoro-2,2-dichloroethylene and 1,1,2-trifluoro-2-chloroethylene, tetrahaloethanes like 1-chloro-2,2,2-trifluoroethane, pentahaloethanes such as 1,1-dichloro2,2,2-trifluoroethane, 1,2-dichloro-1,2,2-trifluoroethane, 1-chloro-1,2,2,2-tetrafluoroethane, 1-chloro-1,1,2,2-tetrafluoroethane, pentachloroethane, 1,1,2,2-tetrachloro-1-fluoroethane, 1,1,1,2-tetrachloro-2-fluoroethane, 1,1-difluoro1,2,2-trichloroethane and 1,2-difluoro-1,1,2-trichloroethane and hexahaloethanes such as 1,1,1-trichloro-2,2,2-trifluoroethane and mixtures thereof.
When 1,1-dichloro-2,2,2-trifluoroethane is the desired hydrochlorofluorocarbon, the preferred starting material is perchloroethylene. When 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) is the desired hydrochlorofluorocarbon, the preferred starting material is 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) or 1,2-dichloro-1,2,2-trifluoroethane (HCFC-123a). When pentafluoroethane (HFC-125) is the desired hydrofluorocarbon, the preferred starting material is HCFC-123, or HCFC-123a or HCFC-124. When 1,1-dichloro-1,2,2,2-tetrafluoroethane (CFC-114a) is the desired chlorofluorocarbon, the preferred starting material is 1,1,1-trichloro-2,2,2-trifluoroethane (CFC-113a). When 1,1,1,2-tetrafluoroethane (HFC-134a) is the desired hydrofluorocarbon, the preferred starting material is 1-chloro-2,2,2-trifluoroethane (HCFC-133a). When the desired hydrochlorofluorocarbon is HCFC-133a, trichloroethylene is the Preferred starting material.
The temperature at which the fluorination reaction is conducted can range, for example, from about 200° to about 450° C., preferably from about 250° to about 400° C. and most preferably from about 290° to about 350° C. with a contact time, of for example, about 2 to about 120 seconds, preferably about 5 to about 80 seconds, more preferably about 8 to about 60 seconds and most preferably about 10 to about 50 seconds. For purposes of this invention, contact time shall be the time required for the gaseous reactants to pass through the catalyst bed assuming that the catalyst bed is 100% void.
The molar ratio of HF to organics (saturated or unsaturated halogenated aliphatic hydrocarbon) can range for example, from about 3:1 to about 12:1, more preferably about 4:1 to about 10:1 and most preferably about 4:1 to about 8:1.
Pressure is not critical. Atmospheric and superatmospheric pressures are the most convenient and are therefore preferred. In Particular, high reaction pressure is desirable for product recovery purposes.
The saturated or unsaturated halogenated aliphatic hydrocarbons, hydrogen fluoride, aluminum oxide hydroxide, chromium oxide and metal salt components of the invention are known materials. Preferably, they should be used in high purity so as to avoid the introduction of adverse influences upon the reaction system.
The fluorination reaction may be conducted in any suitable reaction vessel. The reaction vessel should be constructed from materials which are resistant to the corrosive effects of HF such as HASTELLOY, INCONEL and MONEL.
When the desired hydrochlorofluorocarbon is HCFC-123 and the starting material is perchloroethylene, the by-products produced include HCFC-123a, HCFC-124, HCFC-124a, 1,1,2-trichloro-2,2-difluoroethane, fluorotrichloroethylene, fluorotetrachloroethane, HCFC-133a and perhalogenated ethane
When the desired hydrochlorofluorocarbon is HCFC-124 and the starting material is a mixture of HCFC-123 and HCFC-123a, the by-products produced include HCFC-124a, HFC-125 and perhalogenated compounds.
When the desired hydrofluorocarbon is HFC-125 and the starting material is a mixture of HCFC-123 and HCFC-123a, the by-products which are produced include HCFC-124 and HCFC-124a.
When the desired chlorofluorocarbon is CFC-114a and the starting material is CFC-113a, the by-products which are produced include chloropentafluoroethane.
When the desired hydrofluorocarbon is HFC-134a and the starting material is HCFC-133a, the by-Products which are produced include HCFC-123, HCFC-124 and tetrafluoroethane.
When the desired hydrofluorocarbon is HCFC-133a and the starting material is trichloroethylene, the by-products which are produced include HFC-134a, HCFC-123 and HCFC-124.
Many of the by-products formed during the course of each of the fluorination reactions (i.e., e.g., 1,1,2-trichloro-2,2-difluoroethane (HCFC-122), fluorotrichloroethylene and fluorotetrachloroethane in the case of HCFC-123 and HCFC-124 and HCFC-124a in the case of HFC-125) can be recycled to the reaction vessel for the production of additional HCFC-123, HCFC-124, HFC-125, CFC-114a, HFC-134a and HCFC-133a respectively.
The present invention is more fully illustrated by the following non-limiting examples.
EXAMPLE 1
(a) Catalyst Preparation - - - aluminum/chromium oxide co-extrudate
Ground chromium oxide powder with a median particle size of about 37 microns was mixed with aluminum oxide hydroxide powder with a medium particle size of less than about 0.2 microns. The mole ratio of aluminum:chromium was about 70:30 wt. %. Six weight percent (6 wt %) nitric acid was added to the mixed oxides and the mixture was kneaded to form a thick paste. The paste was then charged to a BRABENDER and extruded using a 1/16 inch single hole die. The extrudate was dried in an oven overnight at 82°-90° C. and was then calcined in a muffle furnace at about 490° C. for 2-3 hours. After cooling, the extrudate was sized to an approximate L/D (length/diameter) of 3. The surface area of the extrudate was 229 m 2 /g.
(b) Catalyst Preparation - - - impregnation of metal salt
245 g of aluminum/chromium oxide extrudate were placed in about 260 ml of 0.24M CoCl 2 solution for approximately 16-20 hours. The wet extrudate was filtered and dried in a vacuum oven at about 100°-110 ° C. for 2.5 days The CoCl 2 loading was 1.4 wt. %.
(c) Calcination and HF Pretreatment
The catalyst is calcined and subsequently treated with HF prior to being used in the fluorination of organics. Approximately 100-110 ml of catalyst were packed into a 1/2 inch MONEL reactor. A steady stream of air at about 2-3 liters/min. flowed through the catalyst bed. The temperature of the reactor was raised rapidly to 400° C. and held at this temperature for 16 hours. Then, the temperature was lowered to 200° C. and air was replaced with nitrogen at about 0.5-1.5 liters/min. HF was pumped in the reactor at about 1-2 ml/min. After the exotherm disappeared, the nitrogen was turned off and the temperature was raised to 400° C. and held for 8 hours.
EXAMPLES 2-5
Preparation of HCFC-123 using the catalyst of Example 1(a)
In this set of examples, the catalyst prePared in Example 1(a), after calcination and pretreatment with with HF, (in accordance with the procedures in Example 1(c)) was used for the fluorination of perchloroethylene. After the catalyst was calcined and pretreated with HF, the reactor temperature was lowered to the desired reaction temperature for fluorination of perchloroethylene. Perchloroethylene was pumped into the reactor and the HF:organics ratio was adjusted to about 8. The reaction was conducted at 200 psig pressure. The reaction conditions and results of the experiments are reported in Table I below. The effluent of the reactor was analyzed using an on-line gas chromatograph.
TABLE 1______________________________________ EXAMPLES 2 3 4 5______________________________________Feed: PerchloroethyleneCatalyst: Al.sub.2 O.sub.3 /Cr.sub.2 O.sub.3Pressure 200 200 200 200psig:Mole Ratio 8 8 8 8(HF/PCE):Temperature 300 310 320 330(°C.):Contact Time.sup.1 38 38 36 26(seconds):Conversion 42 57 68 60PCE (%):Selectivity(%):HCFC-125 0.1 0.2 0.5 0.4HCFC-124 & 124a 1.0 5.6 11.2 10.3HCFC-123 & 123a 30.8 48.9 60.2 56.9Recyclable 66.3 43.8 25.4 28.5By-Products:Non-recyclable 1.1 1.1 2.3 3.4By-products:Combined 120's.sup.2 98.2 98.5 97.3 96.1Productivity(lbs/hr/ft.sup.3):123 & 123a 4.0 8.7 12.8 15.9______________________________________ .sup.1 Contact time = the time required for the gaseous reactants to pass through the catalyst bed assuming the catalyst bed is 100% void. .sup.2 Includes selectivities of HFC125, HCFC124, HCFC124a, HCFC123, HCFC123a and recyclable byproducts.
Hydrofluorination of perchloroethylene produced not only HCFC-123 and 124, but also their respective isomers i.e., HCFC-123a and 124a. The amounts of isomers produced depended on the reaction conditions.
Because HCFC-123a can be isomerized to HCFC-123, the productivity of the process was expressed in pounds of HCFC-123 and 123a per hour per cubic foot of catalyst.
The productivity and selectivity of a catalyst to produce a desired product, in the instant case 1,1-dichloro-2,2,2-trifluoroethane, are the most important parameters to consider in evaluating catalyst performance. Selectivity measures the degree to which the catalyst will produce the desired product to the exclusion of other products while a catalysts' productivity measures the rate at which the catalyst can produce the desired product. Because productivity measures the rate at which a desired product can be Produced for a given amount of catalyst, it is a useful parameter for comparing the performance of different catalysts.
For Examples 2-4, the operating conditions, including contact time, were held essentially constant while the temperature was varied. Generally, the higher the temperature, the shorter the catalyst life. Therefore, it is desirable to use the lowest temperature possible while manitaining a high productivity. A comparison of Examples 2 and 3 reveals that for a 10° increase in temperature, the selectivity of combined 120's remains essentially constant while the productivity of HCFC-123 and HCFC-123a increases by 100%. A comparison of Examples 3 and 4 shows that once again, for a 10° increase in temperature, while the selectivity of combined 120's decreases slightly (i.e., about 0.8%), the productivity increases significantly (i.e., another 50%).
Normally, for commercial production it is desirable to have a productivity which is as high as possible without sacrificing selectivity and catalyst life. Therefore, based on a comparison of Examples 2-4, we conclude that the most desirable operating conditions for the aluminum/chromium oxide catalyst of the invention would be those described in Example 4.
Example 5 shows that productivity can be increased by increasing temperature and decreasing contact time with little effect on the selectivity of combined 120's. Note, once again, that elevated temperature reduces catalyst life.
EXAMPLES 6-9
Preparation of HCFC-123 using the catalyst of Example 1(b)
After calcination and treatment with HF in accordance with the procedures outlined in Example 1(c). the catalyst prepared in Example 1(b) was used for the fluorination of a mixture of 1,1,2-trichloro-2,2-difluoroethane (HCFC-122) and Perchloroethylene. As indicated above, some of the by-products of the reaction, like HCFC-122, are recyclable. Thus, this experiment not only reports on catalyst activity but also simulates by-product recycling. The reaction conditions and results are reported in Table II below.
TABLE 2______________________________________ EXAMPLES 6 7 8 9______________________________________Catalyst: CoCl.sub.2 /Al.sub.2 O.sub.3 /Cr.sub.2 O.sub.3Feed: HCFC-122/PCE(29.63/70.37 wt %)Pressure 200 200 200 200Psig:Mole Ratio 8 8 8 8(HF/Org.):Contact Time.sup.1 38 38 36 36(seconds):Temperature 290 310 320 330(°C.):Conversion -- 48 62 73122 + PCE (%):Conversion 39 65 70 75PCE (%)Conversion -- 7 43 67122 (%):Selectivity(%):HFC-125 0.3 0.3 0.3 0.4HCFC 124 & 124a 1.9 6.4 11.4 18.7HCFC-123 & 123a 45.4 78.7 75.3 69.1Recyclable 46.7 6.2 4.0 2.7By-products:Non-recyclable 5.9 8.5 8.9 9.2By-products:Combined 120's.sup.2 : 94.3 91.6 91.0 90.9Productivity(lbs/hr/ft.sup.3):123 & 123a 3.9 11.8 14.6 15.7______________________________________ .sup.1 Contact time = the time required for the gaseous reactants to pass through the catalyst bed, assuming the catalyst bed is 100% void. .sup.2 Includes selectivities of HFC125, HCFC124, HCFC124a, HCFC123, HCFC123a and recyclable byproducts.
Once again, in this set of Examples, operating conditions, including contact time, were held essentially constant while temperature was varied, a comparison of the selectivities and productivities for these Examples indicates that Example 8 provides the best operating conditions for the aluminum/chromium oxide/cobalt chloride catalyst of the invention resulting in a selectivity and productivity which are highly desirable for commercial production.
COMPARATIVE EXAMPLES 1-2
In this next set of Examples, the activities of three aluminum/chromimum oxide (Al 2 O 3 /Cr 2 O 3 ) catalysts having the same composition (70/30 mol ratio), but prepared by three different methods (i.e. co-extrusion, co-precipitation and agglomerization) were compared. Each catalyst is compared under those conditions which optimize its performance. A detailed description of the method of preparation and results of the comparison are reported below.
Co-extrusion
The catalyst of applicants' Example 4 is used for comparison.
Co-precipitation
This catalyst was prepared in accordance with the method outlined in U.S. Pat. No. 3,258,500 and U.S. Pat. No. 2,402,854. Aluminum hydroxide salt was precipitated with chromium hydroxide salt to give a 70/30 alumina/chromia mixture, (the same mole ratio as used in applicants' Examples 2-9). The catalyst was then calcined and treated with HF in accordance with the method described in applicants' Example 1(c) and subsequently used in the process described in applicants' Examples 2-5. Reaction temperatures were scanned from about 300° to about 400° C.
Agglomerization
A mixture of gamma alumina and chromium chloride hydroxide solution were poured into mineral oil to form spheres. The alumina/chromia spheres were then washed and calcined in air at 500° C. for about 2 hours. Before fluorination, the catalyst was again calcined and treated with HF in accordance with the method described in Example 1(c). The catalyst was then used in the process described in Examples 2-5. Reaction temperatures were scanned from about 300° to about 400° C.
For each of the catalysts, perchloroethylene conversion at different temperatures was plotted. See, attached FIG. 1. From this plot, one can determine and compare the activity of various catalysts (i.e., the higher the percent conversion at a given temperature, the more active the catalyst or, put another way, the higher the temperature needed to achieve a given conversion, the less active the catalyst). FIG. 1 shows that in order to achieve a 40% conversion using the catalyst of the invention, a temperature of only about 300 ° C. is necessary. This is contrasted with the catalysts prepared by co-precipitation and agglomerization which require a temperature of about 330° C. and about 390° C. respectively to achieve the same conversion.
As stated above, generally, catalyst life is dependent on reaction temperature, i.e,. the lower the reaction temperature, the longer the catalyst will last. Based on the data from FIG. 1, it is apparent that the catalyst of our invention is significantly more active than the catalysts prepared by co-precipitation and agglomerization and, since it may be used at lower temperatures, one would expect it to have a much longer catalyst life.
In summary, one can clearly conclude that catalyst activity is very much dependent on the method used to prepare the catalyst and not just on catalyst composition. The Al 2 O 3 /Cr 2 O 3 catalyst of the present invention, prepared by co-extrusion is surprisingly more active than other Al 2 O 3 /Cr 2 O 3 catalysts prepared by co-precipitation and agglomerization and has a much longer catalyst life.
TABLE 3______________________________________ Co-Ex. Agglomerate Co-Ppt.______________________________________Mole Ratio 8 8 8(HF/PCE):Temp. (°C.): 320 375 375PCE Conversion 68 68 35(%):Selectivities:Comb. 120's.sup.1 : 97 90 92Productivity(lbs/hr/ft.sub.3):HCFC-123/123a: 13 12 5______________________________________ .sup.1 Includes selectivities of HFC125, HCFC124, HCFC124a, HCFC123, HCFC123a and recyclable byproducts.
In addition to being significantly more active and having a longer catalyst life than the other catalysts, the data in Table 3 show that the catalyst of the invention is surprisingly significantly more selective for combined 120's and results in a higher productivity than the catalysts prepared by co-precipitation and agglomerization.
EXAMPLES 10-15
Preparation of HCFC-124 using the catalyst of Example 1(a)
After the catalyst was calcined and pretreated with HF in accordance with Example 1(c), the reactor temperature was lowered to the desired reaction temperature for fluorination of HCFC-123 which contained 21.6% HCFC-123a. The HCFC-123 was pumped into the reactor and the HF:organics ratio was adjusted to about 5. The reaction was conducted at 200 psig pressure. The effluents of the reactor were analyzed using an on-line gas chromatograph. The reaction conditions and results of the experiments are reported in Table 4 below.
TABLE 4______________________________________ EXAMPLES 10 11 12 13 14 15______________________________________Catalyst: Al.sub.2 O.sub.3 /Cr.sub.2 O.sub.3Feed: HCFC-123 with 21.6% HCFC-123aPressure: 200 200 200 200 200 200PsigMole Ratio 5 5 5 5 5 5(HF/123):Contact 48 34 34 33 28 46Time.sup.1(seconds):Temperature 330 330 340 350 350 350(°C.):Conversion 51 34 55 64 57 75123 (%):Selectivity(%):HCFC-125: 6.3 3.5 8.3 11.0 9.4 24.2HCFC-124 & 92.6 94.5 90.9 88.4 89.7 75.2124a:Combined 98.9 98.0 99.2 99.4 99.1 99.4120's.sup.2 :Non-recycl- 0.6 0.8 0.5 0.5 0.4 0.4able By-products:Productivity(lbs/hr/ft.sup.3):125: 0.9 0.4 1.5 2.3 2.2 4.9124 & 124a: 14.2 11.8 18.1 20.7 23.6 17.1______________________________________ .sup.1 Contact time = the time required for the gaseous reactants to pass through the catalyst bed assuming the catalyst bed is 100% void. .sup.2 Includes selectivities of HFC125, HCFC124 and HCFC124a.
For Examples 11-13, the operating conditions, including contact time, were held essentially constant while the temperature was varied. A comparison of Examples 11 and 12 reveals that for a 10° increase in temperature, the selectivity of combined 120's stays essentially the same while the productivity of HCFC-124 and HCFC-124a increases by about 50%. A comparison of Examples 12 and 13 indicates that, once again, for a 10° increase in temperature, the selectivity of the combined 120's is virtually unchanged while the productivity of HCFC-124 and HCFC-124a increased by only about 14%. Based upon the above comparasion, we conclude that the most desirable operating conditions for the catalyst would be those described in Example 12 since the productivity remains high without sacrificing selectivity and catalyst life (i.e., the lower the temperature the longer the catalyst life).
In Examples 13-15, the operating conditions, including temperature, were held essentially constant while the contact time was varied. These Examples show that as the contact time increases, the selectivity and productivity of HFC-125 increases while the selectivity and Productivity of HCFC-124 and HCFC-124a decreases.
EXAMPLES 16-19
Preparation of HCFC-124 using the catalyst of Example 1(b)
The catalyst prepared in Example 1(b) was calcined and treated with HF in accordance with Example 1(c) above. The catalyst was then used for the fluorination of HCFC-123. The results and reaction conditions are reported in Table 5 below.
TABLE 5______________________________________ EXAMPLES 16 17 18 19______________________________________Catalyst: CoCl.sub.2 /Al.sub.2 O.sub.3 /Cr.sub.2 O.sub.3Feed: HCFC-123 with 4% HCFC-123aPressure 200 200 200 200psig:Mole Ratio 4 4 4 4(HF/123):Contact Time.sup.1 45 44 43 42(seconds):Temperature 310 330 340 350(°C.):Conversion 11 35 48 59123 (%):Selectivity(%):HCFC-125: 1.0 7.3 9.7 15HCFC-124 98.6 90.5 88.8 83.4& 124a:Combined 99.6 97.8 98.5 98.4120's.sup.2 :Non-recyclable 0.4 2.1 1.5 1.3By-products:Productivity(lbs/hr/ft.sup.3):125: 0.03 1.0 1.8 3.4124 & 124a: 4.6 14.2 18.0 21.1______________________________________ .sup.1 Contact time = the time required for the gaseous reactants to pass through the catalyst bed assuming the catalyst bed is 100% void. .sup.2 Includes selectivities of HFC125, HCFC124, HCFC124a.
In Examples 16-19, the operating conditions, including contact time were held essentially constant while temperature was varied. A comparison of Examples 16 and 17 reveals that for a 20° increase in temperature the selectivity of combined 120's decreases slightly while the productivity of HCFC-124 and HCFC-124a increases by about 208%. A comparison of Examples 17 and 18 shows that for a 10 ° increase in temperature the selectivity of combined 120's stays essentially the same while the productivity of HCFC-124 and HCFC-124a increases by about 28%. Finally, a comparison of Examples 18 and 19 shows that for a 10° increase in temperature the selectivity of combined 120's is unchanged while the productivity increases by about 17%.
Based on the above comparison, we conclude that the optimum operating conditions for the catalyst are those described in Example 17.
EXAMPLE 20
Preparation of HFC-125 using the catalyst of Example 1(a)
The catalyst prepared in Example 1(a) is calcined and treated with HF in accordance with the procedure outlined in Example 1(c) above. This catalyst is then used for the fluorination of HCFC-123. The results indicate that the catalyst of the invention is highly selective for HFC-125 and results in a productivity for HFC-125 which is highly desirable for commercial production.
EXAMPLE 21
Preparation of HFC-125 using the catalyst of Example 1 (b)
The catalyst prepared in Example 1(b) is calcined and treated with HF in accordance with the procedure outlined in Example 1(c) above. The catalyst is then used for the fluorination of HCFC-123. The results indicate that the catalyst of the invention is highly selective for HFC-125 and results in a productivity for HFC-125 which is highly desirable for commercial production.
EXAMPLES 22-24
Preparation of CFC-114a using the catalyst of Example 1(a)
The catalyst prepared in Example 1(a) was calcined and treated with HF in accordance with the procedure outlined in Example 1(c) above. This catalyst was then used for the fluorination of CFC-113a. The results and reaction conditions are reported in Table 6 below.
TABLE 6______________________________________ EXAMPLES 22 23 24______________________________________Catalyst: Al.sub.2 O.sub.3 /Cr.sub.2 O.sub.3Feed: CFC-113aPressure 200 200 200Psig:Mole Ratio 4.9 4.9 4.9(HF/113a):Contact Time.sup.1 46 46 47(seconds):Temperature 300 310 320(°C.):Conversion 81 94 97113a (%):Selectivity(%):HCFC-115: 1.0 7.3 9.7HCFC-114a: 98.6 90.5 88.8HCFC-124 & 0.8 1.0 1.3HCFC-133a:Productivity(lbs/hr/ft.sup.3):114a: 32 38 38______________________________________ .sup.1 Contact time = the time required for the gaseous reactants to pass through the catalyst bed assuming the catalyst bed is 100% void.
For Examples 22-24, the operating conditions, including contact time were held essentially constant while the temperature was varied. A comparison of Examples 22 and 23 reveals that for a 10° increase in temperature, the selectivity for HCFC-114a remained unchanged while the productivity increased 19%. A comparison of Examples 23 and 24 shows that for a 10° increase in temperature the selectivity for HCFC-114a and productivity remain essentially the same. Thus, it appears that the conditions outlined in Example 23 provide the optimum operating conditions for the catalyst.
EXAMPLE 25
Preparation of CFC-114a using the catalyst of in Example 1(b)
The catalyst prepared in Example 1(b) is calcined and treated with HF in accordance with Example 1(c) above. The catalyst is then used for the fluorination of CFC-113a. The results indicate that the catalyst of the invention is highly selective for CFC-114a and results in a productivity for CFC-114a which is highly desirable for commercial production.
EXAMPLE 26
Preparation of HCFC-133a using the catalyst of Example 1(a)
The catalyst prepared in Example 1(a) is calcined and treated with HF in accordance with the procedure outlined in Example 1(c) above. This catalyst is then used for the fluorination of trichloroethylene. The results indicate that the catalyst of the invention is highly selective for HCFC-133a and results in a productivity for HCFC-133a which is highly desirable for commercial production.
EXAMPLE 27
Preparation of HCFC-133a using the catalyst of Example 1(b)
The catalyst prepared in example 1(b) is calcined and treated with HF in accordance with Example 1(c) above. The catalyst is then used for the fluorination of trichloroethylene. The results indicate that the catalyst of the invention is highly selective for HCFC-133a and results in a productivity for HCFC-133a which is highly desirable for commercial production.
EXAMPLE 28
Preparation of HFC-134a using a catalyst prepared according to the procedure set forth in Example 1(a)
A catalyst having the composition of 30 mol % aluminum and 70 mol % chromium oxide was prepared according to the procedures set forth in Example 1(a). The catalyst was then calcined and treated with HF in accordance with the procedure outlined in Example 1(c) above and subsequently used for the fluorination of HCFC-133a. Air was cofed to the reactor with HF and HCFC-133a to maintain catalyst activity. The results and reaction conditions are reported in Table 7 below.
TABLE 7______________________________________ EXAMPLE 25______________________________________Catalyst: Al.sub.2 O.sub.3 /Cr.sub.2 O.sub.3 (30/70)Feed: HCFC-133aPressure 45PsigMole Ratio 4.1(HF/133a):Air Cofeed(O.sub.2 /133a).sup.1 : 2Contact Time.sup.2 12(seconds):Temperature 350(°C.):Conversion 18133a (%):Selectivity(%):HFC-134a: 94HCFC-143a: 0.3HCFC-124: 1.8HCFC-1122: 0.2HCFC-123; 3.3Productivity(lbs/hr/ft.sup.3):134a: 5.0______________________________________ .sup.1 (mole %) .sup.2 Contact time = the time required for the gaseous reactants to pass through the catalyst bed assuming the catalyst bed is 100% void.
The results shown in Table 6 indicate that the catalyst is highly selective for HFC-134a. This reaction was run for more than 800 hours and the catalyst showed no sign of deactivation.
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The invention relates to a novel catalyst and process for producing various chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons said catalyst prepared by co-extruding aluminum/chromium oxide and optionally impregnating the aluminum/chromium oxide support with a metal salt. The chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons, i.e., e.g., 1,1-dichloro-2,2,2-trifluoroethane, produced using the catalyst of the invention are useful in a variety of industrial applications including blowing agent, refrigerant, sterilant gas and solvent applications.
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BACKGROUND OF INVENTION
[0001] This application claims the benefit of U.S. Provisional Application No. 60/186,067, filed Feb. 29, 2000.
BACKGROUND OF INVENTION
[0002] (1) Field of Invention
[0003] This invention relates generally to the field of telecommunications, and more particularly, to a telecommunications system for controlling and monitoring wireless roaming calls for real-time billing, specifically, wireless roaming calls having credit restrictions.
[0004] (2) Background Art
[0005] The telecommunications industry has transitioned to a wireless telecommunications environment with the introduction of wireless telecommunications services (referred to as “wireless services” or simply “wireless”). This transition has resulted in a rise of a myriad of wireless providers who seek to service the growing number of wireless subscribers on a national level, as well as a worldwide level. Providing the wireless subscribers with the ability to place and receive wireless communications regardless of their geographic location is not only a technical challenge, but also requires a complex network and infrastructure. A wireless subscriber may wish to place or receive wireless telecommunications when geographically outside the subscriber's home network. The “home network” is the network or the region serviced by the network of the wireless provider with whom the subscriber has contracted. The wireless provider, however, also wishes to provide telecommunications services to the subscriber even when the subscriber is geographically outside the home network, commonly referred to as roaming outside the home network or simply roaming. The subscriber must be capable of communicating outside of the home network in order for a Roaming Solution to occur.
[0006] However, to provide this service creates a credit risk for the Provider because calls originated by or delivered to the roaming subscriber while roaming in a Local Roaming Provider's network can not be controlled or monitored real-time for account based billing. Due to this potential exposure to credit risk, the wireless providers have, in many cases, refused to provide roaming services to many subscribers in order to mitigate exposure to credit risk. Other solutions to mitigate exposure to credit risk include, credit card calling, various prepay systems including the Applicant's patented system which provides roaming services to prepay unregistered roaming subscribers for call originations only.
[0007] When the subscriber is outside of the home network, the subscriber's equipment searches for a Local Provider's network (local with respect to a roaming subscriber, “Local Provider” could be referred to as “Roaming Provider” or “Serving Provider”) for which it can communicate. This is referred to as roaming. The subscriber's equipment roams until a network provider for which communications can be established is found. The myriad of providers and the growing number of subscribers combined with the complex infrastructure makes a network Roaming Solution a key part to successfully providing nationwide or worldwide wireless services.
[0008] Wireless communication networks and services must provide a Roaming Solution for roaming Registration Notification (Regnot), as well as Roaming Solutions for wireless communications originated by the wireless roaming subscriber and for incoming communications directed to the wireless roaming subscriber. There are various wireless telecommunications interconnect strategies that are designed for servicing the wireless roaming subscriber. A given wireless provider will service both local home subscriber traffic, specifically their own subscribers, however, they will also service roaming subscribers who are not their own who have roamed into the Local Provider's network (i.e., a wireless roaming subscriber).
[0009] As indicated above, wireless subscribers desire to be able to use their mobile phone regardless of their location and this subscriber desire has induced wireless providers to negotiate contracts among themselves to provide roaming services to their subscribers when they are outside the wireless Home Provider's network. A subscriber is considered a roamer when the subscriber's mobile station or mobile phone requires service in a local network which is operated by a wireless provider other than the one to which the subscriber contracts. When a subscriber's mobile station is in the roaming mode, a signal indicative of the roaming condition is provided to the subscriber and is typically displayed on the display of the mobile phone as the result of a comparison of the system identification (SID) of the subscribed system which is stored in the mobile station (mobile phone), with the SID of the system of the Local Wireless Provider which provides a service broadcast from the local base station. This alerts the subscriber of the mobile station that the service being provided is accruing roaming charges. However, the subscriber typically does not have visibility into the actual roaming costs as the contracts between the various wireless providers can vary. Thus, a subscriber can accumulate roaming costs that are higher than anticipated.
[0010] A typical scenario is when the mobile station or mobile phone of the wireless subscriber enters a geographical area outside of its home network that prevents it from obtaining service from the Home Provider's communications network. The mobile station or the mobile phone registers with the Local Provider's (Roaming Provider's) wireless communications system by providing identification information to the Local Provider's mobile switching center (MSC). This identification is referred to as Regnot. The Visitor Location Register (VLR) attached to the Local Provider's MSC has a database of information that identifies other providers with whom they have billing arrangements such that the Local Provider has agreed to provide roaming services to roaming subscribers of the other provider (the Home Provider of roaming subscriber). The VLR maintains records of all service being provided to wireless roaming subscribers. If the other provider or Home Provider of the roaming subscriber is registered in the VLR of the Local Provider, then the VLR will contact the Home Location Register (HLR) of the Home Provider of the roaming subscriber to obtain caller profile information for the roaming subscriber that has roamed into the network of the local or Roaming Provider. The Local Wireless Provider's wireless communications system will then seek authorization to provide service to the roaming subscriber who has roamed into the Local Wireless Provider's network. The HLR of the Home Provider will tell the VLR of the Local Provider whether to provide or not to provide roaming services. Once the roaming services are allowed to be provided, all calls originated by the roaming subscriber are completed by the Local Provider's MSC and RSU. The problem is that the Home Provider has no control over the call originated by the roaming caller. This situation creates a credit risk to the Home Provider. Therefor, Home Providers have opted not to allow roaming services to some subscribers thus they would not be registered with the VLR of the Roaming Provider. Please note, in the telecommunications industry when one refers to a Provider's mobile switching center or switching center or mobile switch or simply switch, it typically implies that an HLR and VLR are included, as well as other necessary hardware. For the purpose of this document, when these terms are used it is implied that the HLR and VLR are included.
[0011] Call delivery to the roaming subscriber when roaming in a Local or Roaming Provider's network can be accomplished current wireless telecommunication infrastructures, however, once the call is terminated at the MSC of the Local Provider, the Home Provider has no means of controlling and monitoring the call. Again, Home Providers have opted not to allow roaming services to some subscribers and again they would not be registered with the VLR of the Roaming Provider.
[0012] If the roaming subscriber is identified in the VLR of the Local Provider, the system of the Local Wireless Provider will send a request to provide service to the home wireless provider's system controller which contains a database referred to as a HLR. The HLR contains user profile information comprising an authorization to permit roaming, user features and information about anticipated roaming costs based upon the various contractual agreements that are in place. The home wireless provider system will then provide information back to the Local Wireless Provider system, including authorization to permit roaming, as well as other features.
[0013] The Applicant has reduced to practice and implemented patented technology that provides real-time call management of a call originated by an unregistered prepay roaming subscriber which addresses part of the problem discussed above, specifically call origination from an unregistered prepay roaming caller. This is an option for those subscribers that the Home Provider has opted not to register with the Local Provider for roaming services. With this technology an unregistered prepay roaming subscriber (a subscriber that the Home Provider opted not to register with the VLR of the Local Provider but is a prepay subscriber) can originate a prepay call. For example, U.S. Pat. No. 6,029,026, issued Feb. 22, 2000, to the present Applicant discloses a network that provides such a service. This patent discloses and claims a telecommunications system that includes a prepay call management platform which is coupled and co-located with a Local Roaming Provider's telecommunications MSC. The system further includes a customer database coupled to the prepay call management platform for storing prepay customer data. The system provides a method for live call management of all prepay calls with unregistered roaming call processing capability. The method includes the steps of recognizing an unregistered roaming call at a Roaming Provider's telecommunications MSC and routing the unregistered roaming call to a prepay call management platform coupled to the telecommunications MSC. This system allows for unregistered roaming calls to be processed locally. This system provides for prepay call management accounting, however, this technology requires the Local or Roaming Provider to have additional hardware infrastructure communicable to and co-located with the Roaming Provider's MSC. The additional infrastructure required includes a Remote Switching Unit (RSU) for terminating the prepay roaming calls. In addition, this patented system only provides for call origination services and not call delivery services (incoming calls directed to the roaming subscriber while in a local network).
[0014] The Regnot of the roaming subscriber that occurs is logged with the home wireless providers system also, which allows the home wireless provider to be aware of the subscriber's location such that the home wireless provider is able to reroute all incoming calls to the Local Provider's MSC for final termination at the subscriber's mobile station. If the mobile station of a subscriber roams from a previously visited provider's network MSC to a newly visited MSC, or back to the Home Provider's network MSC, the home MSC notifies the previously visited MSC to clear any data regarding that mobile station from its system. This process of tracking for call delivery to the roaming caller and actual delivery of the call terminating at the Local Provider's switch is not addressed by the Applicants patented system for account billing.
[0015] In summary there are several shortcomings of the standard wireless communication networks. For example, one shortcoming of the standard network is calls delivered to the roaming subscriber can not be controlled or monitored. Another shortcoming of the standard network is that calls originated by the roaming subscriber either cannot be monitored and controlled at all or if monitoring and control is provided additional infrastructure is required at the Roaming Provider's Site. There is a need in wireless to address the credit risk of some roaming subscribers and provide a system such that wireless providers can provide wireless roaming services to credit risk subscribers while mitigating the credit risk.
BRIEF SUMMARY OF INVENTION
[0016] The invention is a wireless telecommunications Roaming Solution that includes a Regnot function, a roaming call origination function, and a roaming call delivery function. The Roaming Solution integrated with a real-time account billing system equips the Home Provider with the capability to monitor, control and real-time price calls originated by and delivered to credit risk roaming subscribers, for example, prepay roaming subscribers. The Roaming Solution defines a network architecture that comprises multiple network components, including a Roaming Server which acts as a gateway between a National Location Register (NLR), which is also a part of the Roaming Solution, and a call origination remote switching unit. The call origination remote switching unit or the 800 number Remote Switching Unit (800# RSU) is where the wireless roaming call originations will be processed through for central control, which can be generally referred to as a central control RSU or a call origination RSU. The Roaming Server also acts as a gateway between the NLR and an account based billing system to which the Roaming Solution is coupled. The NLR acts as a VLR as seen by the HLR of the Home Provider, and acts as a HLR as seen by the VLR of the Local Roaming Provider. This is accomplished by the NLR tapping into or inserting in the communication link between the HLR of the Home mobile switch and the VLR of the roaming serving mobile switch. The NLR is communicably positioned to intercept messages from the VLR and the HLR. The NLR tracks the location information for the wireless roaming subscribers and contains the HLR information, which provides the subscriber profile information. The NLR and Roaming Server are adapted to be communicably integrated with a standard and unmodified wireless communication network having a home MSC which provides transport and translation support for call originations at the wireless roaming subscriber, and several roaming serving MSCs which provide transport and translation support for terminations to the wireless roaming subscriber. The NLR and Roaming Server is further adapted to be communicably integrated with a real-time billing system such that all roaming calls can be monitored, controlled and real-time pricing and accounting. Thus, Roaming Solution Network System comprises three components and they are the Roaming Server, the NLR and the call origination RSU (800# RSU). Each of these components are adapted such that they can be located at a central location remote from either the Home Provider or the Serving Provider.
[0017] One aspect of the present invention is that all-call originations from wireless credit risk roaming subscriber's can be supported and call monitoring and control will be provided. The real-time call monitoring and control provided by the Roaming Server, and NLR, integrated with a real-time account billing system mitigates, the Home Providers exposure to credit risk. During the Regnot process, the NLR software captures the roaming serving MSCID and provides this to the Roaming Server for use in subsequent rating of call originations. Furthermore, during call origination, the NLR software captures the calling subscribers MIN and dialed digits. This will be provided to the Roaming Server for subsequent use by the centralized 800# RSU in setting up the call to the called party. In response, the NLR software receives a unique dialed number DN for use by the roaming serving MSC to extend the originating call to the 800# RSU. During this aspect of the invention, call termination to the wireless roaming subscriber can be disabled. The centralized location of the Roaming Solution components specifically the NLR, Roaming Server, and the Call Origination RSU alleviates the need for specialized roaming platforms to be co-located at the serving switch to service unregistered prepay roaming subscribers because now they can be registered.
[0018] Another aspect of the present invention is the supporting of call delivery to the wireless credit risk roaming subscribers. Again, due to the Roaming Solution of the present invention, the Home Provider's exposure to credit risk is mitigated. When an incoming call directed to a wireless credit risk roaming subscriber arrives at the home MSC, the MSC routes the call to the RSU of the billing system, which can be referred to as the account billing system RSU. The Account billing system RSU of the billing system queries the Market Server, requesting call validation and then requests from the Roaming Server a temporary local directory number (TLDN) to the Roaming Server MSC. The Roaming Server forwards the request to the NLR. Subsequently, upon request from the Roaming Server, the NLR software will obtain a TLDN from the roaming serving MSC using a route request (ROUTEREQ) message and response. The RSU integrated with the billing system interacting with the Roaming Server utilizes the TLDN to originate a call to the roaming serving MSC for the wireless roaming subscriber. Upon call termination, the call segments from the calling party to the RSU and from the RSU to the called wireless roaming subscriber will be bridged in the RSU integrated with the billing system. As noted above, the NLR software can disable call termination to a wireless roaming subscriber during Regnot. However, when a call to the wireless roaming subscriber is received, the NLR software sends a QUALDIR message to the roaming serving MSC to enable call termination to the wireless roaming subscriber. Upon call disconnect, the Roaming Server will inform the NLR software which then disables call terminations to the wireless roaming subscriber. Please note that the NLR does not take into account the fact that the wireless roaming subscriber has been handed off from its home MSC to a roaming serving MSC or from the serving MSC to its home MSC during a single call instance.
[0019] The invention includes the ability to communicate with an account-based billing and call control platform that allows registered prepaid wireless subscribers to place and receive calls when roaming out of their providers' home networks. The invention verifies that the prepaid wireless subscriber's account balance is sufficient to place or receive the call, translates the account balance into talk minutes, and monitors the call for talk duration. If the prepaid wireless subscriber exceeds the available account balance, the invention tears down the call in the first negative minute and immediately decrements the prepaid wireless subscriber's account. If the call is disconnected before the account balance is depleted, the invention immediately decrements the prepaid wireless subscriber's account and releases the trunks.
[0020] The present invention as described above remedies the short coming of wireless networks that are unable to service high credit risk roaming subscribers without exposing the Home Provider to unacceptable credit risk. The previously unregistered prepay wireless roaming subscriber requiring an unregistered prepay Roaming Solution can now be transitioned to registered account based wireless roaming subscribers. Also, these account based subscribers can be prepay or optionally a credit limited subscriber. These and other advantageous features of the present invention will be in part apparent and in part pointed out herein below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a better understanding of the present invention, reference may be made to the accompanying drawings in which:
[0022] [0022]FIG. 1 is an overall diagram of the Roaming Solution network architecture integrated with a standard SS7 communication network and an account based billing system;
[0023] [0023]FIG. 2 is a call flow diagram of the Regnot process;
[0024] [0024]FIG. 3 is a call flow diagram of call origination by a wireless Roaming Provider (2-stage dialing);
[0025] [0025]FIG. 4 is a call flow diagram of a call origination from a wireless Roaming Provider (single stage dialing);
[0026] [0026]FIG. 5 is a call flow diagram of call delivery at the roaming serving MSC to the roaming subscriber;
[0027] [0027]FIG. 6 is an interface messaging sequence between a roaming serving MSC, a NLR, and a HLR for roaming subscriber Regnot at power up;
[0028] [0028]FIG. 7 is an interface messaging sequence between a roaming serving MSC, an 800# RSU, and a Market Server for roaming call origination which includes a second dial tone from the 800# RSU;
[0029] [0029]FIG. 8 is an interface messaging sequence between a roaming serving MSC, a LLR, a Roaming Server, a Market Server, and an 800# RSU for wireless roaming call origination single-stage dialing;
[0030] [0030]FIG. 9 is an interface messaging sequence between a home MSC, a HLR, a LLR, a local RSU, a Market Server, a Roaming Server, and a roaming serving MSC for call delivery to the roaming serving MSC for the wireless roaming subscriber.
[0031] [0031]FIG. 10 is an interface messaging sequence when a mobile station goes inactive.
[0032] [0032]FIG. 11 is an interface messaging sequence for bulk de-registration of actively registered roaming subscribers.
[0033] [0033]FIG. 12 is an interface messaging sequence for re-registration when a roaming subscriber enters the network of a new serving MSC.
[0034] [0034]FIG. 13 is an interface messaging sequence for re-registration when the roaming subscriber re-enters the home network.
DETAILED DESCRIPTION OF INVENTION
[0035] According to the embodiment(s) of the present invention, various views are illustrated in FIGS. 1 - 13 and like reference numerals are being used consistently throughout to refer to like and corresponding parts of the invention for all of the various views and figures of the drawing. Also, please note that the first digit(s) of the reference number for a given item or part of the invention should correspond to the figure number in which the item or part is first identified.
[0036] One embodiment of the present invention comprises a Roaming Solution system further comprising a Roaming Server and a NLR, and an 800# RSU where the system is adapted to be communicably connected to a standard telecommunications network having a typical Home Provider Infrastructure and a plurality of Roaming Provider Infrastructures, and where the Roaming Solution system is also adapted to be communicably connected to a real-time account billing system having a Market Server and a RSU. The Roaming Solution teaches a novel system and method for providing credit limited wireless roaming services to high credit risk roaming subscribers while mitigating Home Provider exposure to credit risk. The Roaming Solution further allows the Home Provider to make a decision to register the high credit risk roaming subscriber with a plurality of Roaming Provider partners without a fear of substantial credit risk.
[0037] The details of the invention and various embodiments can be better understood by referring to the figures of the drawing. Referring to FIG. 1, an overall network architecture 100 for the wireless Roaming Solution is shown. The network architecture is designed to provide a seamless Roaming Solution. Communication links or paths are shown between the various components of the network. Voice communication paths are indicated as such, for example, voice link 102 between the mobile station or mobile phone 104 and the roaming serving MSC 106 . SS7 communication links are also shown, for example, SS7 communication link 108 between the VLR 110 and the NLR 112 . TCP/IP communication links are also shown, for example, TCP/IP communication link 114 between the NLR 112 and the Roaming Server 116 . A typical SS7 telecommunications network architecture comprises a Roaming Serving MSC 106 that is coupled to a VLR by an SS7 link and that is located at the location of roaming and the network architecture further comprises a home MSC 118 that is coupled to a HLR by an SS7 link and is located at the home location of the wireless roaming subscriber. The network architecture can also include a local billing system RSU 120 that is local to the home location of the wireless roaming subscriber and the local RSU acts as an adjunct switch which controls the wireless roaming call for real-time account billing. The network can also include a Market Server 122 where the rating engine resides for real-time account billing and where the database for the high credit risk subscribers resides. The Market Server and the local billing RSU can be communicably linked by a standard TCP/IP link. The RSU is further communicable with the home MSC via voice links 126 and 128 .
[0038] The network can be equipped with a novel Roaming Solution network system that comprises a Roaming Server 116 , an NLR 112 and an 800# RSU 130 (call origination RSU). The Roaming Solution system is communicably linked through the Roaming Server 1116 , to the local billing system RSU 120 by a standard TCP/IP link 132 , which provides a communicable link to the real-time call monitor and control system for real-time account billing. The components of the Roaming Solution are interconnected by standard TCP/IP links 114 and 134 . The 800#RSU has a voice link 136 to the Roaming Provider's Roaming Serving MSC 106 . The 800# RSU 130 is the component of the Roaming Solution network to which roaming wireless subscriber call originations will be processed through for control. The Roaming Solution Network Roaming Server 116 acts as a gateway between the NLR 112 and the Market Server 122 . The Market Server 122 is the component of the account based billing network where the rating engine and the subscriber database reside.
[0039] The NLR 112 is adapted to be communicably inserted in the SS7 link between the VLR 110 of the Roaming Provider and the HLR 138 of the Home Provider. The NLR 112 is communicably linked to VLR 110 by SS7 link 108 and is communicably linked to HLR 138 by SS7 link 140 . The NLR is adapted to perform the function of an HLR (subscriber profile information processing) and the function of a VLR (registered visitor roaming processing). Therefore, the NLR is adapted to look like an HLR with respect to the VLR and look like a VLR with respect to the HLR. The NLR is communicably adapted to intercept messages from the HLR and the VLR. The network NLR 112 tracks the location information for the wireless roaming subscriber and mirrors the HLR providing the wireless roaming subscriber profile information.
[0040] When the wireless mobile station or wireless mobile phone 104 of a wireless roaming subscriber enters the roaming MSCs 106 area a Regnot occurs. During the Regnot process the NLR 110 software is utilized to provide the DN and the Regnot response message to the roaming serving MSC 106 . The DN is assigned to a centralized 800# RSU 130 to which all-call originations will be processed through for control. Once the mobile station 104 of the wireless roaming subscriber has completed the Regnot process the NLR software can prevent all-call terminations to the wireless roaming subscriber by setting a termination restriction code and the NLR sends a Regnot response message to the roaming serving MSC 106 . At this point all-call originations from the wireless roaming subscriber can be supported.
[0041] Also, please note that during the Regnot process the NLR software captures the roaming serving MSCID and provides the MSCID to the Roaming Server 116 for use in subsequent rating of call originations. During call origination from the wireless roaming subscriber the NLR software captures the calling subscribers MIN and the dialed digits (i.e., called party number). The MIN and the dialed digits are provided to the Roaming Server for subsequent use by the centralized 800# RSU 130 in the setting up of the call to the called party. Responsive to call origination, the NLR software receives a unique DN for use by the roaming serving MSC 106 to extend the originating call to the 800# RSU.
[0042] The network architecture is also adapted to support call delivery or call termination to the wireless roaming subscriber. When the wireless roaming subscriber enters the area of the roaming serving MSC 106 the Roaming Server 116 is made aware of the wireless roaming subscriber's location. Therefore, when an incoming call to a wireless roaming subscriber arrives at the home MSC 118 the home MSC routes the call to the local account billing system RSU 120 . The local account billing system RSU then queries the account billing system Market Server 122 which in turn requests a TLDN from the Roaming Server 116 . The Roaming Server 116 forwards the request for a TLDN to the NLR 112 . Subsequently, upon request from the Roaming Server the NLR software will obtain a TLDN from the roaming serving MSC 106 using a ROUTEREQ message and response. Once the TLDN is provided, the local RSU 120 interacting with the Roaming Server 116 utilizes this TLDN to originate a call to the roaming serving MSC 106 for the wireless roaming subscriber. When the wireless roaming subscriber answers the call, the call segments from the calling party to the local RSU 120 and from the local RSU to the called wireless subscriber will be bridged to the local RSU.
[0043] As noted above the NLR software is adapted to be capable of disabling call termination to a wireless roaming subscriber during the Regnot process. However, when a call to the wireless roaming subscriber is received at the home MSC, the NLR software is adapted to send a message to the roaming serving MSC 106 to enable call termination to the wireless roaming subscriber. Upon call disconnect the Roaming Server 116 can inform the NLR software which then can disable call terminations to the wireless roaming subscriber.
[0044] It should be noted that the wireless roaming subscriber for this network is identified by its mobile identification number (MIN). The wireless roaming subscriber MIN is captured during the Regnot process at which time the NLR software can look up within the internal subscriber lookup table to see if the roaming serving MSC supports call origination by utilizing an origination trigger. If the roaming serving MSCID is not found in the lookup table, the NLR software can load the origination trigger solely based on a transmission capability (TransCap) parameter found in the Regnot message. It is further noted that the NLR does not take into account when a wireless roaming subscriber has been handed off from its home MSC to a serving MSC (non-roaming to roaming) or from the roaming serving MSC to its home MSC (roaming to non-roaming) during a single call instance. The wireless roaming subscriber location is established at the time of Regnot. There is no additional action taken by the NLR to account for the roaming handoff that may result in a change to a wireless roaming subscriber's location when traveling between home MSC areas and roaming serving MSC areas during a single call instance. The handoffs are transparent to the software such that the roaming location of the wireless roaming subscriber is seamless and is only established at the time of Regnot.
[0045] All messages coming from the roaming serving MSC 106 can be routed to the NLR 112 via an SS7 network link 108 . The NLR 112 can extract the wireless roaming subscriber's location information (i.e., MSCID, location area ID and etc.) and store it in the internal database. In addition the NLR may also change some of the profile parameters in the Regnot return result message to enable the wireless roaming subscriber to make and receive calls from and to the roaming serving MSC. The NLR can also pass the wireless roaming subscriber location information to the Roaming Server 116 via a TCP/IP network link 114 .
[0046] The advantages of this Roaming Solution Network System are clear. The integration of the novel system into a standard SS7 or other standard similarly configured telecommunication network is transparent. The Home MSC and related HLR and the serving MSC and related VLR are undisturbed and will operate normally. The call monitor and control account billing system, including the Market Server 122 and local account billing system RSU 120 are undisturbed and will operate as usual. Incoming calls to the Home Provider's switch can be delivered to the previously unregistered but now registered credit limited roaming subscribers. Calls can be originated by these same now registered credit limited roaming subscribers without the need for roaming platforms supporting each roaming providers site. This is all provided while mitigating the risk of exposure to credit risk for the Home Provider.
[0047] Referring to FIG. 2, a call flow diagram for a call Regnot process when the wireless roaming subscriber powers on the mobile phone while in the roaming serving MSC's area or when the wireless roaming subscriber transitions to the roaming area. When the wireless roaming subscriber powers on 202 , the mobile phone 104 , the mobile phone transmits a MIN to the roaming serving MSC 106 which sends a Regnot message 204 via an SS7 network link to a VLR 110 . The VLR for the roaming serving MSC is configured to identify the NLR point code as the HLR for the pre-reserved block of wireless roaming subscriber MINs. Therefore the roaming serving MSC sends the Regnot to the NLR. Upon receiving the Regnot message the NLR can look up the MIN in the internal database of the NLR to see if the wireless roaming subscriber is listed. If the wireless roaming subscriber is listed, the NLR can replace the roaming serving MSCID with the NLR MSCID and forward the Regnot message 206 to the HLR using the direct point code of the HLR. If the wireless roaming subscriber is not listed then the NLR can pass through the message directly to the HLR without any modifications (i.e., the MSCID is not replaced with the NLR ID). The HLR can then respond with a Regnot return result message 208 to the NLR via the SS7 network link. The NLR can modify the Regnot return result message before forwarding it to the roaming serving MSC. The NLR can replace the HLR MSCID with the NLR MSCID. The NLR can set the origination indicator to 8 for all-call originations at the roaming serving MSC. The NLR can also set the digits for destination equal to the 1-800 DN identification services (DNIS) number. Also the NLR can set the termination restriction code to 1 to restrict termination at the roaming serving MSC. The setting of the origination indicator to 8 indicates that all-call originations should be routed to a single NPA-NXX-XXXX. The hot line number (1-800 DNIS number) is configurable for each pre-reserved block of wireless roaming subscriber MINs. The hot line number can be utilized to route the call originations to the centralized 800# RSU. If the termination restriction code is set to 1, or other appropriate code number, (termination denied), no incoming call will be delivered to the wireless roaming subscriber.
[0048] The NLR can then send the location information for the wireless roaming subscriber 210 to the Roaming Server 116 over the TCP/IP link. The Roaming Server can then update the location information for the wireless roaming subscriber and in turn forwards the location information for the subscriber 212 to the Market Server 122 . The Roaming Server then confirms the location message to the NLR. Again please note that the NLR can modify the Regnot return result message before forwarding it back 214 to the roaming serving MSC. The NLR can replace the HLR MSCID with the NLR MSCID. The NLR can also set the origination trigger's field to all-call attempts which will invoke an origination request message to the NLR when the wireless roaming subscriber makes a call. The NLR can also set the termination restriction code to 1, or other appropriate code number, to deny all termination such that no incoming calls will be delivered to the wireless roaming subscriber.
[0049] Once the Regnot process is performed in accordance with the call flow diagram of FIG. 2, call origination from a wireless roaming subscriber can be attempted. Referring to FIG. 3 which shows the call flow diagram for call origination by the wireless roaming subscriber. FIG. 3 is representative of call origination in a telecommunication network where only 2-stage dialing is supported. This is due to the version of the SS7 network or like network where origination request messages are not fully supported. The wireless roaming subscriber originates a call 302 by entering a party's number and sending the requested number from the mobile station 104 . This attempted call origination by the wireless roaming subscriber is routed to the roaming serving MSC 106 and the roaming serving MSC routes the call attempt 304 to the centralized 800# RSU (call origination RSU) 130 by out dialing the 1-800 DNIS number (hot line number) received during registration. Once the 800# RSU receives the call attempt it can collect the requested party's DN and the MIN 306 from the wireless roaming subscriber (can be obtained by second stage dialing) and query 306 the Market Server 122 for call validation. If call validation is positive 308 the Market Server forwards this maximum call duration to the centralized 800# RSU 130 . The centralized 800# RSU then connects the call 310 to the requested party's destination DN. The centralized 800 # RSU can monitor the call to indicate the call has been connected and begins the timing of the call from the time the call was first routed to the 800# RSU. The call can be torn down and disconnected when the call either disconnects at the originating MSC or terminating instrument or when the maximum call duration has been reached.
[0050] The call record is communicated to 312 the Market Server. The advantages of utilizing the Market Server 122 in combination with the 800# RSU 130 as described above is that the call can be monitored and controlled by a central 800# RSU for real-time account billing without need for roaming platforms local to the Roaming Provider's Serving MSC.
[0051] Referring to FIG. 4, a call flow diagram is shown for call origination after Regnot has occurred in accordance with the call flow diagram shown in FIG. 2. Call origination after call registration in accordance with a call flow diagram of FIG. 2 does not require second stage dialing for systems that fully support the origination request message. The wireless roaming subscriber originates a call 402 to the roaming serving MSC 106 and the roaming serving MSC sends an origination request message 404 to the NLR 112 via the VLR 110 . The NLR sends a message 406 which contains the requested party's digits and the wireless roaming subscriber MIN to the Roaming Server 116 over the TCP/IP network link. This information is in turn stored in the Roaming Server. A new unique 1-800 DNIS number can be assigned by the Roaming Server for this call originated by the wireless roaming subscriber. The Roaming Server then returns the 1-800 number 408 to the NLR. The NLR forwards the 1-800 DNIS 410 to the roaming serving MSC in the origination request return result message. The roaming serving MSC can route the call 412 to the 800# RSU 130 via the 1-800 DNIS. The 1-800# RSU queries 414 the Roaming Server to validate the 1-800 DNIS number received. The Roaming Server then looks up the 1-800 DNIS in the internal database to get the requested party's dialed digits and the roaming subscriber's MIN and forwards the request 416 to the 800# RSU to validate the call. The 800# RSU validates the call 418 with the Market Server 122 . If the validation is positive the Market Server provides the maximum call duration to the 800# RSU. The 800# RSU then connects the call 422 to the requested party's destination dialed digits. The 800# RSU can then monitor the call to indicate that the call has been connected and will begin timing the call from the time that the call was first routed to the 800# RSU. The call can be torn down and disconnected when the call either disconnects at the originating MSC or terminating instrument or the maximum call duration has been reached. The call record is forwarded 424 to the Market Server.
[0052] The advantages of utilizing the NLR 112 and the Roaming Server 116 to capture and channel information and to validate and route the call to the 800# RSU are that single-stage dialing is accomplished.
[0053] Referring to FIG. 5, a call flow diagram is shown for call termination or call delivery at a roaming serving MSC 106 for incoming calls 502 to a wireless roaming subscriber. The call flow is initialized by the home MSC 118 of the roaming subscriber receiving an incoming call intended for the roaming subscriber. The home MSC 118 sends a location request message to the HLR 138 in an attempt to locate the wireless roaming subscriber and the roaming serving MSC 106 for which the subscriber is being served. The HLR returns the DN in the location request return result message. The home MSC 118 routes the call 504 to the local account billing system RSU 120 via the DN. The local RSU then queries 506 the Market Server 122 for call validation 508 and requests a TLDN 510 from the Roaming Server. The Roaming Server forwards the request for a TLDN 512 to the NLR 112 . The NLR then sends a qualification directive (QUALDIR) message to the roaming serving MSC 106 to enable call delivery 514 . The NLR then sends a route request message to the roaming serving MSC (VLR) via the SS7 network link requesting a TLDN 514 . The roaming serving MSC then responds with a ROUTEREQ return result message containing the TLDN 516 to the NLR. The NLR then returns the TLDN 518 to the Roaming Server, which in turns forwards the TLDN 520 to the local RSU 120 . The Market Server has already provided the maximum call duration to the local RSU. The local RSU then out dials the TLDN 522 , which in turn routes the incoming call 524 to the roaming serving MSC 106 . The roaming serving MSC then terminates and completes the call 526 to the roaming subscriber. The RSU 120 monitors the call to indicate that the call has been connected and begins timing the call from the time the call was first routed to the RSU. The call can be torn down and disconnected when the incoming call is either disconnected at the originating or terminating instrument or the maximum call duration has been reached. Upon call disconnection, the RSU updates 528 the Roaming Server which in turn forwards disconnect information 530 to the NLR. The NLR disables 532 call termination.
[0054] The advantage is that during Regnot the NLR was identified by the VLR as the HLR, thus the roaming serving MSC registered with the NLR as if it were the HLR. The NLR is able to identify the actual HLR based on looking up the MIN of the roamer. The NLR can then contact the actual HLR and will identify itself (the NLR) as the VLR serving the roamer by providing the actual HLR with NLR MSCID in lieu of the roaming serving MSCID. Therefore, the HLR sees the NLR as the VLR serving the roamer. The NLR also during Regnot contacts the Roaming Server and the Market Server to identify the location of the roamer. The NLR is now the focal point with respect to handling roamer communication. This makes for seamless roaming as the roaming subscriber transitions from one MSC to the next.
[0055] Referring to FIG. 6, the interface message sequence 600 roaming registration is shown. It should be first noted prior to discussing the interface message sequence as outlined in FIG. 6 that all messages from wireless roaming subscribers that are not listed in the NLR database are passed directly to the HLR without any modifications to the Regnot message. The situation of the non-listed subscriber is not what is reflected by the interface message sequence of FIG. 6. FIG. 6 reflects an interface message sequence where the wireless roaming subscriber is listed in the NLR.
[0056] The first interface message in the sequence occurs when the wireless roaming subscriber powers on the phone 614 at which time the mobile station of the subscriber provides the MIN of the subscriber to the serving MSC 602 . The serving MSC 602 sends a Regnot message via the SS7 network to the NLR which includes the MIN of the subscriber and the roaming serving MSCID. Upon receiving the Regnot message, the NLR looks up the MIN in the internal database to see if the subscriber is a listed subscriber. For the listed wireless subscriber, the NLR will replace the serving MSCID and point code with the NLR MSCID and point code and forward the Regnot message 617 to the HLR 606 . Please note, that if the subscriber is not a listed wireless subscriber, the NLR will pass through the message directly to the HLR without any modifications. The HLR will then respond with a Regnot return result message 618 to the NLR. The NLR will then send the location information to the NTC Roaming Server 608 over a TCP/IP interface in a location notification message 620 . The Roaming Server 608 will then return a location notification confirmation message 622 to the NLR 604 . The Roaming Server 608 updates the location information and forwards the location information to the Market Server by transmitting the MSCID 624 to the RSU 610 which in turn transmits the MSCID to the Market Server 612 . In networks where 2-stage dialing is required, the NLR will modify the Regnot return result message in the following ways before forwarding it to the serving MSC. First, the NLR will replace the HLR MSCID with the NLR MSCID. Second, the NLR will set the origination indicator to an all call origination indication. Third, the NLR will set the destination digits equal to the 1-800 DNIS number. Fourth, the NLR will set the termination restriction code to an indication of termination denied. In single-stage dialing, the NLR will modify the Regnot return result message as follows before forwarding it to the serving MSC. Again, the HLR MSCID is replaced with the NLR MSCID. The NLR will set the origination triggers field to all call attempts. The NLR will further set the termination restriction code to an indication that termination is denied. Please note that setting the origination triggers to all call will invoke an origination request message to the NLR when the wireless roaming subscriber makes a call. The NLR shall maintain an internal provisionable table to identify MSCs that can support origination triggeres.
[0057] Once the interface method sequence of FIG. 6 is performed for roaming Regnot, roaming call origination from the wireless roaming subscriber can be provided. Referring to FIG. 7, the interface message sequence for roaming call origination 700 requiring 2-stage dialing is shown for calls originated after the Regnot sequence of FIG. 6 is performed. The interface messaging sequence begins when the wireless roaming subscriber originates a call 702 at the roaming serving MSC 704 . The roaming serving MSC will process the roaming call origination through the centralized 800# RSU 706 via the 1-800 DNIS 708 that was inserted during the Regnot process as shown in FIG. 6. The centralized 800# RSU (call origination RSU) 706 will provide a second dial tone 710 in order to collect the destination digits 712 for making the call connection to the called party. The 800# RSU will then query the Market Server 714 with a rating request message 716 for call validation. The rating request message will provide the MIN of the wireless roaming subscriber and the digits of the destination number. If the Market Server finds that the call validation is positive, the Market Server will send a rating request response message 718 back to the 800# RSU which contains the maximum call duration. Then the centralized 800# RSU connects the call 720 to the destination DN of the party being called. The 800# RSU will monitor the call for pricing 722 .
[0058] Please note the connection between the NLR and the Roaming Server must be monitored to assure that an active connection is maintained. Therefore, there is an interface protocol between the Roaming Server and the NLR over a TCP/IP network link that is designed to monitor the active connection between the Roaming Server and the NLR. The interface monitoring interface protocol is initiated by a NLR. The NLR opens the TCP/IP network link by sending an active connection status check to the Roaming Server. The NLR shall be responsible for sending the active connection status check message at a determined interval. In the NLR active connection status check message the NLR shall report the status of the SS7 link, the database and application to the Roaming Server. The Roaming Server shall be adapted to respond to the active connection status check message with a reply message indicating an active connection. The Roaming Server shall reply back with a reply message within a fixed interval. If the NLR does not see the reply message from the Roaming Server within that fixed interval, the NLR shall close the active connection and shall attempt to reconnect to the Roaming Server. If the reconnection attempt fails, the NLR shall retry at fixed intervals. The reply time interval and the retry time interval are configurable parameters set by the NLR.
[0059] Referring to FIG. 8 the interface messaging sequence is shown for wireless roaming call origination 800 network environment. For roaming call origination to occur, the VLR for this wireless roaming subscriber is set to all-call for the origination trigger during the Regnot procedure. Call origination occurs when the wireless roaming subscriber dials the digits of the desired party and sends the call origination message 802 with the dialed digits to the roaming serving MSC 804 . The roaming serving MSC then transmits an origination request message 806 to the NLR 808 which includes the dialed digits of the party being called. The NLR then shall send the routing information message 810 along with the dialed digits of the party being called to the Roaming Server 812 . The Roaming Server shall then assign a temporary 1-800 DNIS for the wireless roaming subscriber and shall store the 1-800 DNIS together with the dialed digits of the party being called as received in the origination request message. The Roaming Server shall then respond to the NLR with the routing information response message 814 which contains the 1-800 DNIS along with the dialed digits of the desired call. The NLR shall then respond to the roaming serving MSC 804 with an origination request return result message 816 that includes the 1-800 DNIS as the destination digits. The roaming serving MSC 804 is then connected 818 to an 800# RSU (call origination RSU) 824 via the 1-800 DNIS as assigned by the Roaming Server. If the NLR does not receive the routing information response message 820 from the Roaming Server within a defined time interval, the NLR shall retry the routing information message again and shall put the 1-800 DNIS in the routing digits of the origination request return result. The Roaming Server transmits the MIN, dialed digits and MSCID 822 to the 800# RSU 824 . The 800# RSU 824 sends a rating request message 826 from the 800# RSU to the Market Server 828 which includes the MIN of the wireless roaming subscriber and the dialed digits. The Market Server performs a call validation, and if the call validation is positive, the Market Server will respond back with a rating request response 830 , including the maximum call duration, as well as the dialed digits of the party being called. The 800# RSU then connects 832 the calling party to the party being called. The 800# RSU monitors the call for pricing 834 , and transmits to the Market Server.
[0060] Referring to FIG. 9, an interface messaging sequence is shown for delivery of an incoming call at the home MSC to the wireless roaming subscriber at the roaming serving MSC. The call delivery interface messaging sequence 900 is initiated by an incoming call 902 at the home MSC 904 . The home MSC attempts to locate the wireless roaming subscriber. The HLR responds back to the home MSC with a location request response message providing connection information to a local RSU. The home MSC then connects 906 to the local account billing system RSU 908 via the DN and in turn the local billing RSU sends a rating request message 910 to the Market Server 912 which includes the MIN and the digits dialed for call validation. If validation is positive, the Market Server returns the MSCID to the local RSU 908 . A routing request message 916 is sent to the Roaming Server 918 requesting TLDN, which in turn requests the TLDN 920 from the NLR with a routing request message. The NLR 922 shall send a QUALDIR message 924 to the roaming serving MSC 926 to enable call termination for the wireless roaming subscriber. A QUALDIR return message 928 is transmitted back from the roaming serving MSC to the NLR. The NLR shall then obtain a TLDN from the roaming serving MSC utilizing a ROUTEREQ message 930 . Upon receiving the ROUTEREQ return result message 932 from the roaming serving MSC, the NLR shall send a routing request response message 934 with the TLDN to the Roaming Server. The Roaming Server will then send a routing request response message 936 to the RSU 908 , including a TLDN, which in turn is transmitted 938 to the Home MSC 904 . The local RSU will then connect 940 to the wireless roaming subscriber by terminating at the roaming serving MSC thereby completing the call.
[0061] The call can be torn down and disconnected 942 by call disconnection at the home MSC or disconnection 944 at the Roaming Server. The call is priced 946 by the local billing RSU.
[0062] Referring to FIG. 10, a sequence of signals 1000 are shown that occurs when the mobile station is powered off becoming inactive. A power off signal 1002 is transmitted to the serving MSC 1004 . The serving MSC sends a mobile station inactive signal 1006 to the NLR 1008 . The NLR then transmits a location notification signal 1010 to the Roaming Server 1012 . The Roaming Server 1012 then responds back with a location notification confirmation message 1014 . The NLR 1008 then notifies the HLR 1016 with a mobile station inactive signal 1018 . A mobile station inactive return signal 1020 is transmitted back from the HLR to the NLR and the NLR forwards the mobile station inactive return signal 1020 to the serving MSC.
[0063] Referring to FIG. 11, a sequence is shown for a bulk de-registration 1100 . The bulk de-registration is initiated by the serving MSC 1102 which sends a bulk de-registration signal 1104 to the NLR 1106 . The NLR responds back with a bulk de-registration return signal 1108 . The NLR then sends a location notification signal 1110 for each subscriber included in the bulk de-registration to the Roaming Server 1112 . The Roaming Server sends a location notification confirmation signal 1114 back to the NLR. The NLR then sends a mobile station inactive signal for each subscriber in the bulk de-registration 1116 back to the HLR 1118 . The HLR then transmits a mobile station inactive return signal 1120 to the NLR.
[0064] Referring to FIG. 12, the message sequence for re-registration 1200 to a new serving MSC is shown. The sequence is initiated by the new serving MSC 1201 which transmits a registration notification 1204 to the NLR 1202 . The NLR modifies the Regnot and then forwards the registration notification message 1205 to the HLR 1206 . The HLR then transmits a registration notification return message 1208 to the NLR which then forwards the message back to the new serving MSC. The NLR 1202 then transmits a location notification message 1209 to the Roaming Server 1210 . The Roaming Server then transmits a location notification confirmation message 1212 back to the NLR 1202 . The Roaming Server 1210 also forwards the location notification message to the Market Server 1214 and the Market Server responds back with a location notification confirmation message 1216 . The NLR then transmits a registration cancellation message 1218 to the old serving MSC 1220 which in turn responds back with a registration cancellation return message 1222 .
[0065] Referring to FIG. 13, the message sequence for re-registration in the home market 1300 is shown. The message sequence is initiated by the home MSC 1302 transmitting a registration notification message 1304 to the HLR 1306 . The HLR then transmits a registration cancellation message 1308 to the NLR 1310 . The registration cancellation message is then forwarded to the serving MSC 1311 which in turn transmits a registration cancellation return message 1312 back to the NLR. The NLR then forwards the registration cancellation return message back to the HLR 1306 . The HLR then transmits a registration notification return message 1314 back to the home MSC 1302 .
[0066] The various call flow examples shown above illustrate many of the novel aspects of the Roaming Solution. A user of the present invention may choose any of the above call flows, or an equivalent thereof, depending upon the desired application. In this regard, it is recognized that various forms of the subject Roaming Solution could be utilized without departing from the spirit and scope of the present invention.
[0067] As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. It is accordingly intended that the claims shall cover all such modifications and applications that do not depart from the sprit and scope of the present invention.
[0068] Other aspects, objects and advantages of the present invention can be obtained from a study of the drawings, the disclosure and the appended claims.
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The invention is a Roaming Solution network system, the system including a Roaming Server, a National Location Register, and an 800 number Remote Switching Unit. The system is integrated with a standard SS7 type telecommunications network and further coupled to an account based billing and call control platform that allows registered wireless credit limited subscribers to place and receive calls when roaming outside of their Home Provider's network. The invention verifies that the wireless subscriber's account balance is sufficient to place or receive the call, translates the account balance into talk minutes, and monitors the call for talk duration. The Roaming Solution network system is further operable such that if the wireless subscriber exceeds the available account balance, the system tears down the call in the first negative minute and immediately decrements the wireless subscriber's account. If the call is disconnected prior to the account balance being depleted, the invention immediately decrements the wireless subscriber's account and releases the trunks. This Roaming Solution network system is designed to mitigate a Home Provider's exposure to credit risk when providing roaming services to credit limited subscribers.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a syringe based feeder that has a nipple thereon for feeding small animals such as kittens. The feeder also has a guard for helping prevent the animal's paws from interfering with the feeding process.
2. Background of the Prior Art
Baby animals, such as kittens, are dependent on their mother for just about everything, including nutrition, for survival. Unfortunately, sometimes the baby animal is separated from its mother due to death or incapacitation of the mother, forced separation by man, etc. If the baby animal is separated from its mother, either man intervenes and provides for the baby or the baby, too young and immature to fend for itself, dies.
As mentioned, one of the critical functions that man must perform is to feed the baby animal so that it has sufficient nutrition to sustain itself. Normally, the baby animal latches on to a teat of the mother and drinks the milk produced by the mother. Such mother's milk, also consumed by many other animals including man, generally provides all the nutrients needed by the baby animal in the critical first days and weeks of the baby's life. Of course, man lacks such teats or the ability to produce mother's milk for an animal, therefore, other accommodations must be made. Modern science has produced formulas that closely match and often exceed the nutritional qualities of the mother's milk for a baby kitten or other animal. However, even if a specialized formula is not available, simple milk and cream make a great substitute for the non-available mother's milk.
With a nutritional substitute in hand, the next problem becomes actually feeding the animal with the milk or formula. Baby animals often lack the skills and abilities to feed themselves from a bowl or other food source, such skills and abilities being learned over time. To address this, many baby animal caregivers simply use a syringe for the feeding process. An amount of feeding liquid is drawn into the barrel of the syringe through the tip of the hub with the tip being inserted into the kitten's mouth and the plunger being slowly depressed in order to deliver the liquid into the kitten's mouth. While technically sound, this method of liquid delivery is not particularly efficient due to the fact that the tip of the hub is a rather unnatural element for the kitten and the baby animal is reluctant to have the tip placed into its mouth. As a result, the caregiver must force the tip into the kitten's mouth, oftentimes with great struggle with the animal. Not only can such a struggle lead to a mess with formula or milk all over the place, but the relatively delicate animal can suffer an injury.
To address this issue, nursing nipples have been used which nipples cover the tip of the syringe and allow the kitten to draw the liquid from the syringe through the nipple. As the nipple is more natural to the animal, both aesthetically and texturally, the animal is less resistant to its use and is more likely to latch onto the nipple and “nurse” therefrom. The use of a nipple overlying the cold and clinical hub tip of the syringe vastly improves the efficiency of the baby animal feeding process, however, certain shortcoming still remain. The baby animal, being playful by instinct, uses its front paws to engage the hands of the caregiver during the feeding process. This engagement of the hands of the caregiver by the kitten interferes with the feeding process by making it difficult for the caregiver to maintain the nipple within the animal's mouth. Not only can a mess result, but the animal, although having fun with the caregiver, does not ingest the required amount of sustenance during the feeding cycle. To address this problem, a second caregiver engages the paws of the kitten so that the first caregiver can concentrate on maintaining the nipple within the mouth of the animal. While effective, this method is inefficient in that a second person is needed for each feeding cycle, which can be expensive in a commercial setting such as a veterinarian's office, and possibly difficult to obtain in a private home setting when a person is alone with the kitten.
What is needed is a system whereby a baby animal such as a kitten can be easily and effectively fed via a nipple tipped syringe wherein the playfulness of the animal does not adversely interfere with the feeding process. Specifically, such a system must allow a single person to be able to feed the baby animal and keep the animal's paws engaged on an area other than the caregiver's hands. Ideally, such a system is of relatively simple design and construction so as to be relatively inexpensive to manufacture and obtain.
SUMMARY OF THE INVENTION
The syringe feeder with nipple and guard of the present invention addresses the aforementioned needs in the art by providing a syringe based feeding device for baby animals such as kittens with a feeding nipple overlying the tip of the syringe hub. The syringe feeder with nipple and guard also provides a subsystem that can be engaged by the kitten's paws allowing the kitten to be naturally playful during feeding, which playfulness does not adversely interfere with the feeder's hands so as not to adversely affect the feeding process. The syringe feeder with nipple and guard is of relatively simple design and construction, being made using standard manufacturing techniques, so as to be readily affordable to a large percentage of potential consumers for such a product. The syringe feeder with nipple and guard is relatively easy to use, maintain, and clean.
The syringe feeder with nipple and guard of the present invention is comprised of a syringe that has a barrel and a plunger slidably disposed within the barrel. The barrel has a shoulder on an end thereof and a hub extending outwardly from the shoulder, the hub having a tip with a first opening. A scratch pad has a second opening such that the scratch pad is removably attached to the syringe by passing the tip and the hub through the second opening with the scratch pad abutting against the shoulder of the barrel. A nipple structure has a nipple thereon and is removably attached to the hub of the syringe so that the scratch pad is sandwiched between the nipple structure and the shoulder. The scratch pad may have a rigid backing member. The nipple structure has a cap attached to the nipple such that the cap is either frictionally or threadably attached to the hub. Alternately, a stand is provided that has a forward leg with a front surface and a slot that has a cutaway section. The stand is capable of being freestanding. A scratch pad is removably attached to the front surface of the forward leg. A plate has a second opening such that the plate is removably attached to the syringe by passing the tip and the hub through the second opening such that the plate abuts the shoulder of the barrel. The nipple structure sandwiches the plate between itself and the shoulder of the syringe. The scratch pad is removably attached to the front surface of the forward leg by having a first portion of hook and loop material disposed on the front surface and having a second portion of hook and loop material disposed on scratch pad such that the first portion of hook and loop material and the second portion of hook and loop material cooperatively mate with one another. The stand may also have a support leg for providing the freestanding capability of the stand.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the syringe feeder with nipple and guard of the present invention.
FIG. 2 is a perspective view, partially exploded, of the syringe feeder with nipple and guard of FIG. 1 .
FIG. 3 is a perspective view of an alternate configuration of the syringe feeder with nipple and guard of the present invention.
FIG. 4 is a perspective view, partially exploded, of the syringe feeder with nipple and guard of FIG. 3 .
Similar reference numerals refer to similar parts throughout the several views of the drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, it is seen that the syringe feeder with nipple and guard of the present invention, generally denoted by reference numeral 10 , is comprised of a typical syringe 12 having a barrel 14 with a plunger 16 slidably disposed within the barrel 14 and a handle 18 attached to the plunger 16 for controlling movement of the plunger 16 within the barrel 14 . A hub 20 has a tip 22 with an opening 24 , the hub 20 extending from a shoulder 26 of the barrel 14 . The syringe 12 works in the usual way in that the plunger 16 is slid to the hub 20 end of the barrel 14 via the handle 18 . The opening 24 of the tip 22 is placed within a desired liquid and the plunger 16 is slid away from the hub 20 via pulling of the handle 18 . This rearward sliding of the plunger 16 creates a vacuum within the barrel 14 so that the liquid is drawn into the barrel 14 via the opening 24 of the tip 22 as a result of the vacuum so created. Once the barrel 14 is filled with a desired amount of the liquid, the liquid is extracted from the barrel 14 by pressing on the handle 18 so as to push the plunger 16 toward the hub 20 end of the barrel 14 thereby forcing the liquid back out of the opening 24 of the tip.
As seen, a guard 28 has a central opening 30 , a relatively rigid backing 32 (although not required), and a relatively soft scratch pad 34 . The scratch pad 34 may be of any appropriate scratch pad material such asm by way of example, foam or similar soft material covered in an appropriate cover such as cloth, leather, Nylon, etc., or other appropriate covering material, the overall guard 28 acting as a scratching pad for a kitten or other baby animal. If a backing 32 is used, the covering material may be removable therefrom for ease of cleaning of the scratch pad 34 . The guard 28 is fitted on the syringe 12 by passing the hub 20 through the opening 30 on the guard 28 . The back of the guard 28 buts up against and seats on the shoulder 26 of the syringe 12 . The guard 28 is maintained on the syringe 12 by attaching a nipple structure 36 , having a nursing nipple 38 and a cap 40 , onto the hub 20 of the syringe 12 so as to sandwich the guard 28 onto the syringe 12 . The cap 40 has a diameter that is greater than the diameter of the opening 30 of the guard 28 so as to prevent the guard 28 from slipping off of the syringe 12 . The nipple structure 36 is maintained on the hub 20 of the syringe in any appropriate fashion, including having the cap 40 of the nipple structure 36 be threadably attached to the hub 20 (threading on hub 20 not illustrated) or by having the cap 40 frictionally fit onto the hub 20 , etc. The size of the syringe 12 and the attached nipple 38 of the nipple structure 36 is selected based on the size of the animal being fed using the device 10 .
In order to use the syringe feeder with nipple and guard 10 of the present invention, the syringe 12 is filled with a desired liquid, such as formula or cream. The guard 28 is attached to the syringe 12 and the nipple structure 36 is attached to the syringe 12 so as to maintain the guard 28 in place. The device 10 is now ready for use. The kitten is fed the liquid within the syringe 12 via the nipple 38 of the nipple structure 36 . The baby animal is able to scratch on or otherwise play with the scratch pad 34 of the guard 28 so as not to interfere with the hands of the feeder.
As seen in FIGS. 3 and 4 , in an alternate embodiment of the syringe feeder with nipple and guard 110 , a plate 142 has a central opening 144 which central opening 144 is fitted over the hub 20 of the syringe 12 . The nipple structure 36 holds the plate 142 in the usual way as described for the first embodiment of the syringe feeder with nipple and guard 10 . A stand 146 has a front face 148 located on a forward leg 150 thereof, a support leg 152 , and a slot 154 with a cutaway portion 156 . A scratch pad 134 is removably attached to the front face 148 of the stand 146 . The scratch pad 134 is made in similar fashion to the previously described scratch pad 34 such as foam or similar material covered in an appropriate cover such as cloth, leather, Nylon, etc., or other appropriate covering material and acts as a scratching pad for a kitten or other baby animal. The removable attachment of the scratch pad 134 to the front face 148 of the stand 146 may be by any appropriate means known including the use of a first portion 158 of cooperating hook and loop material (which includes the new cooperating hook and pile material) attached on the underside of the scratch pad 134 and a corresponding second portion 160 of cooperating hook and loop material attached to the front face 148 of the stand 146 so that the first portion 158 of hook and loop material cooperatively mates with the second portion 160 of hook and loop material in order to attach the scratch pad 134 to the front face 148 of the stand 146 . The forward leg 150 and the support leg 152 act together to make the stand 146 freestanding. Of course other architectures can be used to make the stand 146 freestanding. For example, the forward leg 150 may have a horizontally extending support (not illustrated) which support holds the stand 146 upright without the need for a support leg.
In order to use this embodiment of the syringe feeder with nipple and guard 110 of the present invention, the syringe 12 is filled with a desired liquid, such as formula or cream. The plate 142 is attached to the syringe 12 and the nipple structure 36 is attached to the syringe 12 so as to maintain the plate 142 in place. The scratch pad 134 is attached to the front face 148 of the stand 146 . The plate 142 is slid into the slot 154 at the top of the stand 146 so that the plate's opening 144 —and the held syringe 12 —is within the cutaway portion 156 . The syringe 12 is now held in place attached to the stand 146 . The kitten may now feed from the device 110 as desired. The baby animal is able to scratch on or otherwise play with the scratch pad 134 attached to the stand 146 so as not to interfere with the hands of the feeder. If the animal is sufficiently strong so as to be able to suck liquid out of the syringe without the need for a caregiver to depress the plunger 16 , the animal may be left unattended with this embodiment of the syringe feeder with nipple and guard 110 . When feeding is over, the plate 142 and its held syringe 12 are slid out of the slot 154 , the nipple structure 36 is removed from the hub 20 and thereafter the plate 142 is removed from the hub 20 . The syringe 12 is refilled, cleaned, or otherwise disposed of as needed. The scratch pad 134 may be removed from the front face 148 of the stand 146 in order to be cleaned or replaced as needed.
While the invention has been particularly shown and described with reference to embodiments thereof, it will be appreciated by those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention.
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A hand feeding system for small animals, such as kittens, uses a syringe that has a nursing nipple removably attached to the hub end of the syringe. Either a scratch pad is interposed directly between a shoulder of the syringe and the nipple or a plate is so interposed such that the plate is removably attached to a freestanding stand that has a scratch pad located thereon.
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BACKGROUND
The invention relates to devices for cooling the engine of a motor vehicle with combustion-engine or hybrid propulsion comprising an internal combustion engine.
More particularly, the invention relates to the cooling of the engine compartment overall.
In general, motor vehicles are equipped with an engine compartment incorporating an internal combustion engine closed off by a lower fairing, a heat exchanger, such as a radiator, through which a coolant passes and a fan placed upstream of the heat exchanger in order to blow air toward the engine and thus cool the internal combustion engine when the vehicle is in operation.
Any component able to close off the lower part of the engine compartment, which is generally open, in order to improve the aerodynamics of the vehicle is referred to as a “lower fairing”.
However, such a system allows only the front of the combustion engine to be cooled, and the cooled air has difficulty reaching the rear part of the engine, which means that some components of the engine are not sufficiently cooled and may be damaged by the heat.
In addition, when the internal combustion engine is stopped or running at low idle, the components in the engine compartment, and notably those on top of the engine, are subjected to a phenomenon of natural convection. What happens is that when the vehicle is no longer moving along, air situated in the confined region of the engine compartment is heated up to a large extent so that the components are subjected to high thermal stresses and may become damaged by the heat.
Reference may be made to document US 2010/0181050 which describes a vehicle comprising two fans which are intended to cool the front of a combustion engine via a heat exchanger. A first fan is powered by an electric motor and emits air through a heat exchanger. The air emitted by the first fan is recovered to drive a second fan able to convert the mechanical energy into electrical energy and to recharge an electric battery.
However, such a system is difficult to install because the combination of two fans leads to a significant bulk. In addition, such a system is unable to cool all of the components situated in the engine compartment once the vehicle is stopped.
Reference may also be made to document US 2010/0244445 which describes a turbine designed to turn a fan, of substantially horizontal axis, intended to cool the front of a combustion engine via a heat exchanger and to convert the work supplied by the fan turned by the flow of air coming from the outside into electrical energy and recharge an electric battery.
Such a system requires the combination of a turbine and of a fan in order to recharge an electric battery and is likewise unable to cool all of the components situated in the engine compartment once the vehicle is stopped.
BRIEF SUMMARY
It is therefore an object of the present invention to overcome these disadvantages.
The object of the invention is therefore to provide a motor vehicle comprising a device that allows the internal combustion engine compartment to be cooled effectively, while having a small bulk.
Another object of the invention is to provide a device for cooling the internal combustion engine compartment that operates autonomously in terms of electrical energy.
The subject of the present invention is a motor vehicle with combustion-engine or hybrid propulsion comprising at least one internal combustion engine arranged in an engine compartment, a lower fairing intended to close off the lower part of the engine compartment.
The motor vehicle comprises a fan of vertical axis and an electric motor supplying the fan with electrical energy, said fan being arranged substantially horizontally in the lower fairing under the internal combustion engine compartment, so as to blow air in a substantially vertical direction toward the internal combustion engine.
Thus, by incorporating the motor-fan unit directly into the lower fairing, the components arranged in the combustion engine compartment are effectively cooled, even the components arranged around the combustion engine.
According to one embodiment, the electric motor is supplied with electrical energy by the electrical network of the motor vehicle.
According to another embodiment, the electric motor is supplied with electrical energy by an autonomous electrical-energy generation and storage means.
The autonomous electrical-energy generation and storage means may be recharged with electrical energy by the rotation of the fan set in rotation by the movement of a flow of air when the motor vehicle is in motion.
The electric motor is, for example, a DC motor or comprises permanent magnets arranged at the end of the fan and a coil embedded in the lower fairing, the autonomous electrical-energy storage means being recharged with the current induced by the variation in magnetic flux that is created as the fan rotates.
Advantageously, the motor vehicle comprises an electronic control unit able to set the fan in rotation as a function of the temperature measured by a measurement means in the combustion engine compartment.
Furthermore, the motor vehicle may comprise an air intake flap operated by the electronic control unit as a function of the speed of the vehicle, of the state of charge of the autonomous electrical-energy generation and storage means, and of the temperatures measured by at least one measurement means in the internal combustion engine compartment.
According to one embodiment, the engine compartment and the lower fairing are arranged at the rear of the motor vehicle.
Thus, by incorporating the vertical-axis fan into the lower fairing it is easy for internal combustion engines arranged at the rear of the vehicle to be cooled suitably despite the small space which is unable to accommodate a conventional cooling device comprising a heat exchanger and a horizontal-axis fan upstream of the heat exchanger.
Advantageously, the motor vehicle comprises an internal combustion engine cooling device arranged upstream of the internal combustion engine and comprising a heat exchanger through which a coolant circulates and a second fan of horizontal axis arranged upstream or downstream of the heat exchanger and intended to blow or suck air through the heat exchanger in a substantially horizontal direction toward the internal combustion engine.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention will become apparent from reading the following description given solely by way of nonlimiting example and given with reference to the attached drawings in which:
FIG. 1 schematically illustrates a front or rear part of a motor vehicle according to the invention;
FIG. 2 depicts a view of the vehicle of FIG. 1 from underneath;
FIG. 3 depicts a ventilation device according to one embodiment of the invention;
FIG. 4 depicts a ventilation device according to another embodiment of the invention;
FIG. 5 schematically illustrates a front or rear part of a motor vehicle according to the invention; and
FIG. 6 schematically illustrates a front or rear part of a motor vehicle according to the invention
DETAILED DESCRIPTION
FIGS. 1 and 2 schematically illustrate a front or rear part of a motor vehicle with combustion-engine or hybrid propulsion, referenced 1 overall, comprising an engine compartment 2 intended to house the internal combustion engine 3 .
The lower part 2 a of the engine compartment 2 has an opening closed off by a lower fairing 4 . The lower fairing 4 is, for example, an attached component made of synthetic material, such as polypropylene or polyamide for example.
The lower fairing 4 has the effect of improving the aerodynamics of the motor vehicle by reducing or even eliminating the creation of an area of turbulence of the flow of air entering the internal combustion engine 3 compartment 2 .
The lower fairing 4 encloses a motor-fan unit 5 comprising a fan 5 a of vertical axis Y and an electric motor 5 b supplying the fan 5 a with electrical energy. The fan 5 a is arranged substantially horizontally X in the lower fairing 4 under the internal combustion engine 3 compartment 2 so as to blow fresh air in a substantially vertical direction Y toward the internal combustion engine 3 and notably toward the components situated on top of the internal combustion engine 3 .
In the remainder of the description, the term “electric motor” defines all machines that convert electrical energy into mechanical energy or mechanical energy into electrical energy.
As illustrated, the lower fairing comprises a fresh air intake duct 4 a and an air intake flap 4 b operated by an electronic control unit (ECU) 6 intended to control the opening and closing of the air intake flap 4 b , for example by means of actuators 4 c , as a function of the temperature in the engine compartment 2 as measured by one or more temperature sensors 7 .
When the motor vehicle is in operation, the flow of air admitted by the air intake duct 4 a drives the fan 5 a which cools the internal combustion engine 3 .
When the motor vehicle is stopped or the combustion engine 3 is running at low idle, the air flow is not sufficient to drive the rotation of the fan 5 a and the combustion engine 3 compartment 2 , through a phenomenon of natural convection, is subjected to high thermal stresses. The fan 5 a is therefore set in rotation by the electric motor 5 b , making it possible to cool the combustion engine 3 compartment. The air blown by the fan 5 a is directed along the vertical axis Y and flows through louvers 8 situated on one side of the combustion engine 3 compartment 2 . The name “louvers” is given to any component made up of inclined vanes or slats that allow the hot air present in the engine compartment 2 to be removed.
As illustrated in the figures, the electric motor 5 b is supplied with electrical energy by an autonomous electrical-energy generation and storage means 9 , such as an electric battery for example.
The autonomous electrical-energy generation and storage means 9 is recharged with electrical energy by the rotation of the fan 5 a driven in rotation by the movement of a flow of air when the motor vehicle 1 is in motion, the fan 5 a therefore operates in “generator” mode. The flap 4 b can also be operated as a function of the speed of the motor vehicle and of the state of charge of the electric battery 9 .
When the vehicle 1 is stopped or the internal combustion engine 3 is running at low idle, the autonomous electrical-energy generation and storage means 9 supplies electrical energy to the motor 5 b of the fan 5 a in order to set it in rotation and the fan 5 a then operates in “motor” mode.
The electric motor 5 b may for example be a DC motor or may be an AC motor.
As a DC motor is, by definition, reversible, it operates in “generator” mode and in “motor” mode.
As illustrated in FIGS. 3 and 4 , the AC motor consists of the combination of magnetized means 10 situated on the circumference of the fan 5 a and of coils 11 embedded in the material of the lower fairing 4 .
The magnetized means 10 are, for example, in the form of a magnetic ring as illustrated in FIG. 3 or in the form of permanent magnets arranged at the ends of each of the blades 5 c of the fan 5 a , as illustrated in FIG. 4 .
In the case of such an AC motor, the autonomous electrical-energy storage means 9 is recharged by the variation in magnetic flux that is created as the fan 5 a rotates. However, it is necessary to have a device (not depicted) for rectifying the alternating current.
The electronic control unit 6 is able to control the “generator” or “motor” mode of operation of the fan as a function of the temperature measured by a measurement means 7 in the combustion engine 3 compartment 2 .
When the fan 5 a is operating in “motor” mode, the electronic control unit 6 generates a rotary electromagnetic field that allows the fan 5 a to be rotated through the collaboration of the magnetized means 10 with the coils 11 embedded in the lower fairing 4 .
As an alternative, the electric motor 5 b could be supplied with electrical energy by the electrical network ( 14 in FIG. 5 ) of the motor vehicle, without the use of an autonomous electrical-energy generation and storage means 9 .
The engine compartment 2 and the lower fairing 4 may be arranged at the rear or at the front of the motor vehicle 1 .
The motor vehicle 1 may also comprise a conventional device for cooling the internal combustion engine 3 arranged upstream of the internal combustion engine 3 and comprising a heat exchanger ( 12 in FIG. 6 ) through which a coolant circulates and a second fan ( 13 in FIG. 6 ) arranged upstream or downstream of the heat exchanger and intended to blow or suck air through the heat exchanger in a substantially horizontal direction of the internal combustion engine 3 .
Because the motor-fan unit is incorporated directly into the lower fairing, the components housed in the engine compartment are effectively cooled, notably the components arranged on top of the internal combustion engine.
Furthermore, by virtue of the invention, the engine compartment is cooled during the phases in which the combustion engine is running, running at low idle, and stopped.
In addition, because the vertical-axis fan is incorporated into the lower fairing, it is easy to provide internal combustion engines arranged at the rear of the vehicle with sufficient cooling despite the small space which is unable to accommodate a conventional cooling device comprising a heat exchanger and a horizontal-axis fan upstream of the heat exchanger.
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A combustion or hybrid powered motor vehicle including at least one internal combustion engine arranged in an engine compartment, a lower housing configured to enclose a lower portion of the engine compartment, a fan including a vertical axis and an electric motor supplying the fan with electrical energy, the fan arranged substantially horizontally in the lower housing under the internal combustion engine compartment.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a petroleum water heater and, more particularly, to a liquid hydrocarbon fuel combustor to be used with the water heater or the like.
2. Description of the Prior Art
As burning means for burning a liquid hydrocarbon fuel, there has been available in the prior art what is called a "gun-type burner". This burner ignites a mixture of air, which is blown from a blower motor, and kerosene droplets, which are pressurized by an electromagnetic pump and atomized by a nozzle, by a high-voltage discharge thereby to burn that mixture. Nevertheless, the gun-type burner generally has a high ratio of excess air so that it has an accordingly low heat efficiency. Because of the yellow or yellowish-orange flame combustion, moreover, carbon left unburned deposits on the inner wall of the can-type body of the burner thereby to deteriorate the initial efficiency, and the resultant burning noises are large. From the standpoint of economy of energy and resources, therefore, there arises a requirement for improving the efficiency, or, from the standpoint of prevention of noises to the neighbourhood in urban lives, there arises a requirement for dropping the sound level of the noises. In order to meet those requirements, there has been developed a combustion system such as a rotary gas burner or a heater evaporation system, in which kerosene droplets are gasified to ensure the blue flame combustion. However, the former system has a defect that an offensive order is emitted as a result of the incomplete gasification of the kerosene during the time period from the ignition to the instant when the flame become stable and at the time when the flame is quenched. On the other hand, the latter system is inconvenient, when used, in that the combustion cannot be instantly started because of necessity for a time period for preheating the heater, and has a difficulty that a control mechanism such as a mechanism for controlling the temperature of the heater has a complicated construction. Both the systems are basically improved in that the kerosene droplets are gasified but they are so complicated as to require special skills when they are maintained and are to be inspected. The present invention is directed to what is called a "recirculation system", as is different from those systems according to the prior art. The recirculation system is known in the art as one of countermeasures for reducing emission of nitrogen oxides NO x from boilers for business use. According to the recirculation system, the flame is changed into a blue one by the use of a remarkably large-scale apparatus for recirculating a portion of the combustion gas to the back of a fuel atomizing nozzle thereby to control the content of the NO x in the combustion gas. The application of that recirculation system as it is to a domestic petroleum water heater or the like has invited with difficulty the problems that the burning noises are large and that the running cost is high.
SUMMARY OF THE INVENTION
The present invention has been conceived with a view to eliminating all the defects of the various systems thus far described.
Therefore, it is an object of the present invention to provide a liquid hydrocarbon fuel combustor which can make use of such can-type body and gun-type burner as are generally used in the prior art.
Another object of the present invention is to provide a liquid hydrocarbon fuel combustor which has a simple construction.
A further object of the present invention is to provide a liquid hydrocarbon fuel combustor which is highly efficient but has low noises.
According to a major feature of the present invention, there is provided a liquid hydrocarbon fuel combustor comprising: a fresh air blast pipe disposed in a hole, which is formed in a portion of the circumferential wall of a cylindrical can-type body, and having its leading end opened toward a combustion chamber which is formed in said can-type body; a fuel atomizing nozzle disposed in said blast pipe for atomizing a liquid hudrocarbon fuel from the leading end opening of said blast pipe into said combustion chamber; an electrode rod for igniting and burning the mixture of the liquid hydrocarbon fuel droplets, which are injected from said fuel atomizing nozzle, and the fresh air which is blown from said blast pipe; a mixing tube disposed in front of the leading end opening of said blast pipe in the atomizing direction such that it is coaxially connected to said blast pipe and having at least its front half counter-tapered in a diverging form; and a flame holding plate fixed upright in said mixing tube in a manner to face the atomizing direction of said fuel atomizing nozzle and having a porous or reticulated construction, wherein the improvement resides in that the connecting portion of said blast pipe and said mixing tube is formed with a gap which is so sized as to allow the combustion gas circulating along the inner wall of said cylindrical combustion chamber to flow into a rear end opening of said mixing tube.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
In FIGS. 1 to 4 showing a first embodiment of the present invention:
FIG. 1 is a longitudinal section showing a heat exchanger;
FIG. 2 is a transverse section showing the heat exchanger;
FIG. 3 is a transverse section showing a combustor; and
FIG. 4 is a partially sectional perspective view showing the combustor; and
FIG. 5 is a transverse section showing a portion of a combustor according to a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail in the following in connection with the embodiments thereof with reference to the accompanying drawings.
FIGS. 1 to 4 show a heat exchanger A according to a first embodiment of the present invention. As shown, the heat exchanger A is constructed of a cylindrical can-type body 17 and a combustor B which are disposed in a housing 21. The combustor B is disposed to face a combustion chamber which is formed in the internal space of the can-type body 17. Between the inner wall 10 and the outer wall 20 of the can-type body 17, moreover, there is formed a reservoir 18 in which a fluid to be heat-exchanged is reserved. Indicated at reference number 19 is a insulator which is arranged on the outer circumference of the can-type body 17.
The combustor B is equipped with a fuel atomizing nozzle 8 for injecting the liquid hydro-carbon fuel, which is pressurized by a hydraulic pump 23, in the form of mist-shaped fine droplets. Around the outer circumference of said nozzle 8, there is disposed a blast pipe 2 for blowing the air which is sent by a blower fan 24. Indicated at numeral 3 is a swirling air flow injection plate which is disposed at the leading end opening 14 of the blast pipe 2. That injection plate 3 is formed at its central portion with one fuel injection port 4 for injecting an air-fuel mixture and at its circumferential edge portion with a plurality of (e.g., six or more) air injection ports 5 which are so equi-distantly arranged as to enclose said fuel injection port 4. Those air injection ports 5 are inclined at such respective angles with respect to the circumferential and axial directions of the injection plate 3 as to establish swirling flows in the air injected therefrom so that the fuel and the air may be uniformly mixed. Indicated at numeral 9 is an electrode rod which is connected with the secondary (i.e., higher voltage side) terminals of an ignition transformer for establishing a spark in the vicinity of the leading end of the fuel atomizing nozzle 8 thereby to ignite the fine droplets of the fuel which is injected from said atomizing nozzle 8. In front of and at a predetermined spacing from said blast pipe 2, there is disposed a flame holder C which has a multi-cylinder construction. That spacing needs to have such dimentions that the combustion gas to circulate along the inner wall 10 of the cylindrical combustion chamber 22 can flow into the rear end opening of a mixing tube 6. Hence, that spacing will be termed a circulating flow inlet 1 in the following. The multi-cylinder flame holder C is equipped at its center with a flame holding plate 13 which is made of a punched stainless steel plate. Said flame holding plate 13 is supported on the inner circumference of the mixing tube 6, which in turn is suspended on the blast pipe 2 by means of legs 7, by means of supporting legs 15. Around the outer circumference of the flame holding plate 13, moreover, there is disposed a counter-tapered flame holding member 12 which is made of a finely porous material and which diverges toward the downstream. Around the outer circumference of that flame holding member 12, still moreover, there is disposed an auxiliary flame holding member 11 which is fabricated by punching a stainless steel plate. The flame holding member 12 is used to increase stability of a combustion flame whereas the auxiliary flame holding member 11 is used to smoothen propagation of a flame front when the orange flame combustion shifts to the blue flame combustion immediately after the start of the combustion. Those flame holding members makes laminar the flow of the mixture, which contains the fine droplets of the combustible liquid fuel and the gasified liquid fuel, thereby to augment the stability of the combustion flame.
On the inner wall 10 of the can-type body 17 and at the side facing the fuel atomizing nozzle 8, on the other hand, there is disposed a guide 26 for smoothly shunting the combustion gas thereby to prevent turbulences from being generated. That guide 26 is formed at its center with a projecting ridge 26c at which its two sides 26a and 26b merge into each other. Moreover, the aforementioned two sides 26a and 26b are curved the more to the right and left in the more downstream of the combustion gas. Still moreover, the guide 26 thus constructed is set to have such a height from a refractory base 27 placed on the bottom of the combustion chamber 22 as is twice as large as the height H of the flame holder C of the combustor B. This construction is adopted so that the combustion gas injected to diverge vertically to some extent from the flame holder C may be wholly made to circulate. Reference numeral 28 indicates an exhaust funnel, and numerals 29, 30 and 31 indicate an outlet port, an inlet port and a drain, respectively, of the fluid to be heat-exchanged. Indicated at numeral 32 is a control cylinder for preventing the combustion gas from being straightly exhausted.
Next, the operating modes of the heat exchanger A having the construction thus far described will be described in case the fluid to be heat-exchanged is water whereas the liquid fuel is kerosene. Here, both the flow rates of the fuel and air to be supplied per unit time to the combustor B are constant. The fresh air supplied via the opening 14 of the blast pipe 2 from the blower motor (although not shown) is fed to the mixing tube 6 which is disposed in front of said blast pipe 2. After this, the fuel pressurized by the hydraulic pump (although not shown) is atomized into the mixing tube 6 by the atomizing nozzle 8 which is arranged toward the combustion chamber 22 in the cylindrical can-type body 17. Simultaneously with the start of the air blowing operation, moreover, the droplets of the liquid fuel, which are atomized by the fuel atomizing nozzle 8, are ignited by the flame, which is generated at the electrode rod 9 by the high voltage generated by the ignition transformer (although not shown), so that the orange flame combustion is started from the vicinity of the opening 14 of the blast pipe 2. The resultant combustion gas impinges upon the guide 26 which is arranged at such a position on the inner wall 10 of the can-type body as faces the flame holder C. The combustion gas is then shunted by the projecting ridge 26c at the center of that guide 26 to flow along the surfaces of the curved sides 26a and 26b so that the two flows gently and smoothly change their directions. After this, the combustion gas flows along the inner wall 10 of the can-type body while exchanging its heat with the water in the reservoir 18. Then, the combustion gas reaches the circulating flow inlet 1, which is formed between the flame holder C and the blast pipe 2 and in which it is sucked into the mixing tube 6 by the actions of both the vacuum (or suction) established by the high-speed swirling air flow coming from the swirling air flow injection plate 3 and the dynamic combustion pressure of the circulating combustion gas itself. Within the mixing tube 6, the fresh air and the liquid fuel droplets are appropriately mixed with the combustion gas coming in a circulating manner so that the liquid fuel droplets are activated by the heat of the combustion gas circulating either to become more finer or to be gasified, until the mixture is fed toward the flame holding plate 13 disposed in the atomizing direction. As a result, the flame burning in the vicinity of the opening 14 of the blast tube 2 is gradually moved in the atomizing direction. The flame thus moved is propagated first to the rear end portion of the auxiliary flame holding member 11 and then to the flame holding plate 13, in which it starts the continuous and stable blue flame combustion. After that, the combustion gas continues its recirculation so that, when the mixing rate of the fresh air with both the combustion gas having recirculated and the liquid fuel droplets reaches a proper value, the flame expands its combustion range along the counter-tapered inner wall downstream of the mixing tube 6, whereby the continuous blue flame combustion is stably held at the flame holding plate 13 and over a wide area of the inner wall downstream of the mixing tube 6. In other words, it is possible to establish the combustion which has low noises and an excellent heat efficiency.
In order to ensure the aforementioned blue flame combustion, thus, it is necessary to mix a appropriate amount of combustion gas with the mixutre of the air and the liquid fuel droplets. Then, the level of the vacuum (or suction) generated in the circulating flow inlet 1 raises a problem. With this problem in mind, the inventor has conducted experiments by changing the flow speed of the air to be injected, which will exerts the most influence upon the aforementioned vacuum. The experimental results have revealed that the flow speed sufficient to suck such a flow rate as is necessary for the ideal ratio of excess air can be set if the dimensions of the combustor are determined. The factors to exert influences upon the flow speed of the air injected include the internal diameters of the fuel injection port 4 and the air injection ports 5 and the area ratio of the two injection ports 4 and 5, if the output of the blower fan 24 and the size (e.g., 80 mmφ, in this case) of the blast pipe 2 are constant. Incidentally, the number of the air injection ports 5 and the distance between the fuel injection port 4 and the air injection ports 5 hardly influence the flow speed of the injected air so that they can be neglected. If the distance between the two injection ports 4 and 5 exceeds its proper value, however, it becomes impossible to ensure satisfactory mixing of the liquid fuel droplets and the air. In the case of the present embodiment in which the blast pipe 2 has an internal diameter of 80 mmφ, the above-specified proper distance is 32 mm.
Tables 1 and 2 tabulate the experimental results and indicate the relationships among the internal diameters of the injection ports 4 and 5, the flow speed of the injected air and the flow rate of the air supplied. Incidentally, the experiments were conducted outside of the heat exchanger A.
TABLE 1______________________________________Internal diameter of blast pipe 2 = 80 mm.0.Internal diameter of injection port 4 = 18 mm.0.No. of I.D. (mm.0.) Flow Speed Flow Rate of AirPorts 5 of Ports 5 (m/sec) Supplied (m.sup.3 /sec)______________________________________16 7.0 22 0.01916 7.5 21.5 0.02116 8.0 21 0.02216 8.5 19.5 0.02316 9.0 19 0.024______________________________________
As is apparent from Table 1, it the internal diameter of the air injection ports is made small, the flow speed of the air injected is increased to enlarge the vacuum to be established in the circulating air inlet 1. On the contrary, the flow rate of the air supplied for the combustion has a tendency to be decreased as the internal diameter of the injection ports 5 is reduced. With this in mind, therefore, the internal diameter of 8 mmφ is required for having a sufficient flow rate of the air supplied and a high flow speed.
TABLE 2______________________________________Internal diameter of blast pipe 2 = 80 mmφNumber of injection ports 5 = 16Internal diameter of injection ports 5 = 8 mmφ 4PortofI.D. ##STR1## (m/sec)SpeedFlow (m.sup.3 /sec)Suppliedof______________________________________ AirRateFlow16 20 21 0.02118 24 21 0.02220 28 20 0.02222 32 19.5 0.02324 36 19 0.024______________________________________
As is apparent from Table 2, moreover, if the internal diameter of the fuel injection port 4 is reduced, the flow speed is increased, but the flow rate of the air supplied is decreased. Moreover, the ratio of the effective area of the fuel injection port 4 to the total effective area of the fuel injection port 4 and the air injection ports 5 takes such a value as accords to the change in the flow rate of the air supplied. With the balance between the flow rate of the air supplied and the flow speed of the injected air flow being taken into consideration, therefore, the internal diameter of the fuel injection port 4 has the most proper value of 18 to 20 mmφ.
The air flow speed actually metered was 21 m/sec for the internal diameter 18 mmφ of the fuel injection port 4, the internal diameter 8 mmφ of the air injection ports 5, the number 16 of the air injection ports 5 and the internal diameter 80 mmφ of the blast pipe 2. For reference pupose only, the air flow speed of the combustor of the prior art, which is commercially available in the market, is ordinally about 12.5 m/sec.
In short, according to the first embodiment, the guide 26 for shunting the combustion gas and gently and smoothly changing the flow direction of the same is disposed at a position where the combustion gas impinges upon the inner wall 10 of the can-type body so that the combustion gas generates no substantial turbulences at said portion while being freed from any large noises which might otherwise be generated by the turbulences. In the mixing tube 6, moreover, since the liquid fuel droplets are heated into a gasified or near state by the circulating combustion gas and since the combustion is effected with the blue flame at a ratio of excess air near the stoichiometric value by adding the combustion gas to the mixture of the air and the liquid fuel droplets, the calory to be liberated for a predetermined amount of fuel is so high that an excellent heat efficiency can be attained. Since the combustion is sustained with the laminar, stable blue flame, still moreover, there can be achieved an advantage that the burning noises are low. Since the carbon generated is little, furthermore, it does not deposit upon the inner wall of the can-type body so that the efficiency is not degraded.
Table 3 compares the performances of the petroleum water heater using the gun-type burner of the prior art and the petroleum water heater using the recirculation type burner according to the first embodiment of the present invention.
TABLE 3______________________________________ Prior Art Invention______________________________________Efficiency 75% 90%A - Noise 50 dB 42 dB(by JIS)C - Noise 70 dB 62 dB(by JIS)Temp. of 450° C. 280° C.ExhaustGasSmoke 2 0Scale No.CO.sub.2 (%) 10 14______________________________________
Since substantially instant shift is effected from the orange flame combustion to the blue flame combustion in accordance with the present invention, furthermore, little offensive order is emitted. Furthermore, interchangeability with the gun-type burner of the prior art can be enjoyed because use is made of the can-type body which is ordinally used. Thanks to the simple construction, furthermore, there can be attained advantages that the maintenance and inspection are facilitated and that the production cost is low.
Turning now to FIG. 5 showing a second embodiment of the present invention, from which both the flame holding member 12 and the auxiliary flame holding member 11 of the foregoing first embodiment are omitted. The remaining struction is absolutely the same as that of the first example. Even with this simplified construction, the combustor, which can sufficiently endure the practical use and which is highly efficient while generating low noises, can be finally provided likewise the case of the first embodiment partly by properly selecting the distance between the blast pipe 2 and the mixing tube 6 and partly by adjusting the position of the flame holding plate 13 although the distance selection and the position adjustment are troublesome.
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Herein disclosed is a liquid hydrocarbon fuel combustor which includes a fresh air blast pipe disposed in a hole formed in the circumferential wall of a can-type body. The leading end of the blast pipe is opened toward a combustion chamber which is formed in the can-type body. A fuel atomizing nozzle is disposed in the blast pipe for atomizing a liquid hydrocarbon fuel from the leading end opening of the blast pipe into the combustion chamber. An electrode rod is disposed in the blast pipe for igniting and burning the mixture of the liquid fuel droplets, which are injected from the atomizing nozzle, and the fresh air which is blown from the blast pipe. A mixing tube is disposed in front of the leading end opening of the blast pipe in the atomizing direction such that it is coaxially connected to the blast pipe. The mixing tube has at least its front half counter-tapered in a diverging form. A flame holding plate is fixed upright in the mixing tube in a manner to face the atomizing direction of the nozzle and has a porous or reticulated construction. The connecting portion of the blast pipe and the mixing tube is formed with a gap which is so sized as to allow the combustion gas circulating along the inner wall of the combustion chamber to flow into a rear end opening of the mixing tube.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a division of application Ser. No. 08/244,096 filed Sep. 19, 1994 which application is now U.S. Pat. No. 5,645,830, which is a 371 of PCT/CA92/00491 filed Nov. 13, 1992.
FIELD OF THE INVENTION
This invention relates to compositions and methods employing said compositions for preventing urogenital tract infections.
BACKGROUND TO THE INVENTION
It is well known that indigenous, non-pathogenic bacteria predominate on intestinal, vaginal and uro-epithelial cells and associated mucus in the healthy state, and that pathogenic organisms (such as bacteria, yeast, chlamydia, viruses) predominate in the stages leading to and during infections. Organisms such as Escherichia coli, enterococci, candida, Gardnerella and Klebsiella originate from the bowel, colonize the perineum, vagina, urethra and can infect the bladder and vagina. Treatment with antimicrobial agents is required to eradicate the organisms. However, infections can and do recur, for the urinary tract in an estimated 80% of cases. Prolonged use of antimicrobial agents creates drug resistant pathogens, breakthrough infections and a disruption of the normal flora. The possibility that indigenous bacteria have a role in preventing infection has been postulated for many years, but few studies have been carried out to identify specific bacteria and their properties required for such an effect. U.S. Pat. No. 4,314,995 to Hata et al. investigated anaerobic, lactobacilli-like organisms as a means of treating a number of infectious diseases, but no consideration was given to the combined importance of their hydrophobicity, hydrophillicity, adhesiveness to biomaterials, epithelial cells, mucus and tissues, and no discussion was included to prevent urogenital infections. U.S. Pat. No. 4,347,240 to Mutai et al. discloses a composition and method employing a specific strain of lactobacilli to inhibit tumour growth.
In recent years, our group has investigated the use of lactobacillus to prevent recurrent urinary tract infections, particularly in adult women. Our conclusion has been that the ability of lactobacilli to adhere, inhibit, competitively exclude and coaggregate formed the basis for the protection of the host. However, new and more important information has now come to light, further to human and experimental studies. The invention now takes into account a new infectious state (post-antimicrobial urogenital infections) as distinct from simple urinary tract infection. The former is initiated following use of antimicrobial agents. This application was not obvious previously, as previous literature has concentrated on virulence characteristics of pathogens causing problems, ignoring the fact that recurrences can follow the use of external agents. We previously recognized resistance to nonoxynol-9 as being important for selection of lactobacillus. However, the usage of this agent is not universal, and just because a strain can resist its action does not infer that it offers every lactobacillus strain the crucial component of protecting the host.
The ability of lactobacillus to produce inhibitory substances has been believed by us to be important. One obvious such product would be hydrogen peroxide. However, based upon our latest findings, this property is present in strains that do and those that do not protect women from reinfection. Thus, inhibitory activity is not the primary mechanism for prevention of infection.
The adherence of lactobacillus to epithelial cells has been regarded as important in the context of blocking access of pathogens to surfaces. However, what was not recognized previously was the hydrophobic and hydrophillic properties of these strains and the production of proteinaceous adhesions into the environment (supernatant). These new findings were not obvious and in fact describe totally new methods whereby lactobacilli colonize biomaterial and human cell surfaces. The use of intestinal cell monolayers has provided a system more closely related to the in vivo situation, showing that colonization of the intestine (to compete with uropathogenic organisms before they emerge to colonize the urogenital tract and infect the bladder and vagina) must reach higher levels (10 to 165 lactobacillus per cell) to achieve potential protection.
In addition, we now realise that the in vitro adherence levels for lactobacillus to uroepithelial cells bear little resemblance to those found in the in vivo situation, when compared directly. In other words, a count of 65 bacteria per cell in vitro does not always give a count of 65 per cell in vivo. All it can show is that the strain has adhesion potential. In fact, we now know that a level of >0 bacteria per vaginal cell in vivo (along with evidence of some adhesion on cells even when the mean is zero), and a viable count of >100 lactobacillus per ml from a tissue swab, is a preferred characteristic to measure adhesion. The preferred characteristic for the desired result is for a strain to colonize the surface and retain viability and reproduce.
A better understanding of the species of lactobacilli in the vagina has now been acquired by us. In addition, new strains have been examined for various parameters, and their origin, type, identity and properties were not previously known or assumed.
We previously recognized that lactobacillus adhesion to urinary catheters could provide a mechanism for protecting a catheterized patient against urinary tract infection. Infections in these patients are widespread and can be fatal, especially in an acute care setting. Data has been accumulated (Hawthorn and Reid, "Exclusion of uropathogen adhesion to polymer surfaces by Lactobacillus acidophilus", Journal of Biomedical Materials Research, Vol. 24, 39-46 (1990)) to further support the theory that lactobacillus coated onto a catheter can prevent uropathogenic bacteria from adhering. However, the practicality of adhering lactobacillus to a prosthetic device in a manner that would provide a stable product was not obvious, nor was it investigated. Rather, the new information on lactobacillus demonstrates that catheter colonization should come via hydrophobic and hydrophillic adhesion of the organisms to the urethra, from where they themselves will attach to the catheter. This new approach is a significant deviation from the published works, as it takes account of the new lactobacillus properties and the knowledge that catheters are either hydrophobic (TFX silicone) or hydrophillic (Bard and Kendal Foley Lubricated catheters). It also provides a new concept, whereby the lactobacilli do not block uropathogenic adherence as the main means of protecting the host directly, but rather they bind with the uropathogens and form a more normal flora that is less able to infect the host.
The use of skim milk as a potential carrier for lactobacillus was previously considered by us. However, no investigations had been carried out with this substance. In addition, the material was seen as a neutral component that, if anything, would provide a lactobacillus preparation with stability and growth potential in the host. What was not appreciated and what has now been discovered is that specially prepared skim milk and other specific lactobacillus growth factors, called LGF, can be used to stimulate the growth of a patient's own normal flora, to the extent that it could protect the patient against urogenital infection.
By "especially prepared skim milk" is meant skim milk suspended in phosphate buffered saline, autoclaved to eradicate proteinaceous and living contaminants, then freeze dried. By "specific lactobacillus growth factors" is meant substances which stimulate preferentially only growth of lactobacillus and not uropathogens, or alternatively which stimulate significantly more lactobacillus than uropathogen growth. These latter substances are present in skim milk power, lactobacillus microbiological growth media and in other composite compounds and elsewhere.
SUMMARY OF THE INVENTION
The present invention provides a method for the prevention of post-antimicrobial infections caused by pathogenic organisms which comprises administering skim milk powder vaginal suppositories, LGF or an amount of hydrophobic and/or hydrophillic lactobacillus which have a contact angle with water >19 degrees, which are highly adherent to biomaterials, intestinal, vaginal and uro-epithelial cells, which are resistant to certain antimicrobial agents and which dominate the urogenital flora.
The invention utilizes safe and effective amounts of one or more of the said aforementioned skim milk LGF substance or lactobacilli in a pharmaceutically acceptable carrier. The actual composition can be instilled in the form of a freeze dried preparation, cream, paste, gel, liquid or suppository for intestinal, oral, vaginal, urethral or periurethral instillation.
By "safe and effective" as used herein is meant an amount high enough to significantly positively modify the condition to be treated but low enough to avoid serious side effects (at a reasonable benefit/risk ratio) within the scope of sound medical judgement. The safe and effective amount will vary with the particular condition being treated, the severity of the condition, the age and physical condition of the patient, and the type of preparation or lactobacillus being used.
In the practice of the method as hereinabove defined the lactobacillus may be administered as viable whole cells. The lactobacillus species may be aerobically grown, preferably selected from the group consisting of L. casei, L. acidophilus, L. plantarum, L. fermentum, L. jensenii, L. gasseri, L. cellobiosus, L. crispatus, and L. brevis, more particularly, selected from the group consisting of L. casei var rhamnosus GR-1, L. fermentum B-54 (ATCC 55884), L. casei RC-17 (ATCC 55825), RC-15, 55, 8, 70, 36 (ATCC 55841), 62, 65, L. acidophilus RC-14 (ATCC 55845), 68, 75, L. plantarum RC-20 (ATCC 55883), RC-6, L. jensenii RC-28 (ATCC 55918), L. casei RC-15, and L. gasseri 60 (ATCC 55844).
The lactobacillus species may be microaerophillically grown, preferably, selected from the group consisting of L. casei, L. acidophilus, L. plantarum, L. fermentum, L. jensenii, L. gasseri, L. cellobiosus, L. crispatus, and L. brevis, more particularly, selected from the group consisting of L. casei var rhamnosus GR-1 (ATCC 55826), L. fermentum B-54 (ATCC 55884), L. casei RC-17 (ATCC 55825), RC-15, 55, 8, 70, 36 (ATCC 55841), 62, 65, L. acidophilus RC-14 (ATCC 55845), 68, 75, L. plantarum RC-20 (ATCC 55883), RC-6, L. jensenii RC-28 (ATCC 55918), L. casei RC-15, and L. gasseri 60 (ATCC 55844).
The infection may be associated with the use of a urinary catheter or other prosthetic device.
In further aspects, the invention provides a method for the prevention of urinary tract infections of a mammal in need of such treatment which comprises coating at least a portion of the urogenital tract and/or bioinaterial prosthesis with lactobacillus, skim milk or LGF; and a method for the prevention of urinary tract infections of a mammal which utilizes a composition comprising lactobacillus organisms, skim milk or LGF within a suitable pharmaceutically acceptable carrier.
The pharmaceutically acceptable carrier may be in the form of a gelatin suppository, especially useful for oral and/or vaginal implantation, and comprise skim milk or LGF in powder or other form.
The lactobacillus of use in the practice of the invention further preferably attaches to human epithelial cells to a level of 10 to 165 organisms per cell; and wherein the mechanism of adhesion of lactobacillus involves hydrophobic or hydrophillic interactions and involves non-proteinaceous cell wall adhesions on the lactobacillus and proteinaceous adhesions in the surrounding supernatants.
In a more preferred aspect, the invention provides a method to prevent post-antimicrobial urogenital infections caused by pathogenic organisms which method comprises administering an amount of skim milk, LGF, lactobacillus, or supernatant within a pharmaceutically acceptable carrier.
Preferably, the pathogenic organisms are bacteria or fungi.
In a most preferred aspect, the invention provides a method to prevent recurrent urogenital infections in mammals caused by pathogenic organisms which method comprises the steps of (a) administering an effective amount of a urogenital antimiobial agent to substantially eradicate agent--vulnerable said pathogenic organisms; and
(b) administering an effective amount of skim milk powder vaginal suppository, LGF or hydrophobic and/or hydrophillic lactobacillus which have a contact angle with water ≧19 degrees, which colonize biomaterials, intestinal, vaginal and uroepithelial cells, which are resistant to said antimicrobial agent, and which dominate the urogenital flora.
In a further aspect of the invention the method comprises administering said urogenital antimicrobial agent in admixture with said skim milk and/or LGF and/or lactobacillus.
An example of such an admixture is a suppository containing 0.25 g freeze dried lactobacillus, plus 0.25 g specially prepared skim milk powder or LGF plus 160 mg trimethoprim plus 800 mg sulfamethoxazole. Alternatively, it contains 0.25 g freeze dried lactobacillus, plus 0.25 g specially prepared skim milk powder or LGF, plus 400 mg norfloxacin. Other antimicrobial agents include those used to treat urinary tract infections, namely: penicillins, beta-lactams, aminoglycosides, cephalosporins, tetracyclines, nitrofurantoins, fluoroquinolones, as well as other agents and combinations, in addition to nystatin, estrogen and nonoxynol-9. These suppositories are administered preferably by oral route but also by vaginal route, in an appropriate amount and for a suitable duration to have the desired effect (for example, twice daily for three to seven days).
Accordingly, the invention further provides a pharmaceutical composition comprising said urogenital antimicrobial agent in admixture with said skim milk and/or lactobacillus and/or LGF and, optionally, a pharmaceutically acceptable carrier, therefor.
Thus, the invention provides novel methods of preventing post-antimicrobial urogenital infection by either the two-step method defined, hereinabove, or by the above single step incorporating the concurrent eradication of antimicrobial susceptible pathogenic organisms by said antimicrobial agent together with enhancement of the natural flora over said pathogenic organism resistant to said antimicrobial agent by the presence of said skim milk, LGF or lactobacillus.
Examples of urogenital antimicrobial agents of use in the practice of the invention are nonfloxacin and trimethoprim/sulfamethoxazole (TMP/SMX or co-trimoxazole).
Each of the ingredients, antimicrobial agent, skim milk, LGF and lactobacillus strains are provided during the method in sufficient amounts to effect treatment. Such amounts and methods of applications required reside within the skill of the art.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be illustrated by means of the following non-limiting examples, wherein FIG. 1 illustrates the number of lactobacillus per ml isolated from vaginal swabs taken from the two patient groups during the 12 month study of Example 2.
EXAMPLE 1
In order to verify that lactobacillus suppositories and skim milk suppositories can reduce the recurrence of urinary tract and vaginal infections, a study was performed on 40 patients. Each patient had urinary tract infection and was treated with 3 days antimicrobial therapy (norfloxacin or co-trimoxazole) then given one vaginal suppository immediately after cessation of therapy. The gelatin suppository contained >10 9 viable L. casei GR-1 (ATCC 55826) and L. fermentum B-54 (ATCC 55884) which are known to adhere to cells and produce inhibitory products against uropathogenic organisms. Control patients received specially prepared skim milk powder in the same capsules at the same dosage. The suppositories were given two times a week for two weeks, then only once at the end of the first and second month. The recurrence rate after six months was expected to be over 60% based upon literature reports. The results showed:
Recurrence rate with lactobacillus suppositories=21%
Recurrence rate with specially prepared skim milk suppositories=47%
More recurrences occurred after co-trimoxazole therapy 41% than after norfloxacin therapy 29%.
In more detail, the materials and methods were as follows:
Patients
Forty-one premenopausal women, mean age 23 (±4.4) years, entered the study via one of two university outpatient clinics. Patients were not included in the study if they were pregnant or diabetic; if they had known allergies to fluoroquinolones or TMP/SMX or a history of urinary cancer or other complications associated with the urinary tract (e.g. urinary obstruction); or if they were taking any medications other than those used in the study. Patients were included in the study if they showed signs and symptoms of acute lower UTI with dysuria, frequency, urgency, or nocturia, but no flank pain or fever. They also had to have positive screening results for bacteriuria based on a test of a fresh, midstream urine specimen using a leukocyte esterase strip. During the study, patients were not catheterized nor were they given systemic antimicrobials or anticoagulants. Informed consent was obtained from the patients and the clinical research was conducted following the guidelines for human experimentation of the Toronto General Hospital.
Study Design
The sample size was calculated, not to determine significant efficacy, but rather as a preliminary examination of safety and of potential for use in postantimicrobial suppository therapy.
Each study patient was given a three day supply of either norfloxacin (400 mg twice daily) or TMP/SMX (160 mg/800 mg). The allocation was blinded and random. Urine culture confirmed the presence or absence of bacteria (≧10 5 organisms per ml of urine) and if no organisms were detected, the therapy was discontinued on day 2. On day 3, each patient randomly received one capsule of freeze-dried lactobacillus or (as placebo) sterilized skim-milk powder to be used intravaginally. The suppositories were inserted twice weekly for two weeks, and then at the end of each of the next two months. Urine cultures were taken during follow-up visits at 48 hours, two weeks, five weeks, three months, and six months. At the same time, vaginal swabs were obtained and cultured semiquantitatively in MRS (deman, Rogosa, Sharpe) agar to determine if lactobacilli were present and which types of flora were dominant.
Vaginal Suppositories
Lactobacillus casei var rhamnosus GR-1 and Lactobacillus fermentum B-54 were cultured for 24 hours at 37° C. with 10% carbon dioxide in MRS broth, washed in phosphate-buffered saline, and resuspended in 10% specially prepared skim-milk powder. To each size AA gelatin capsule was added 0.5 gm of lactobacilli, representing more than 1.6×10 9 organisms per vial. (These organisms have a long shelf life; their viability has been found to drop less than 10% within 12 months). The skim-milk powder was suspended in saline, sterilized, and placed in 0.5 g capsules identical to those containing the lactobacilli. Both types of capsules were then packaged in sterile plastic containers, which were randomly dispensed by the hospital pharmacy.
Outcomes Monitored
Two outcomes were monitored; (1) whether antimicrobial therapy eradicated the bacterial UTI and eliminated symptoms within three days, and (2) to what extent infections recurred. Asymptomatic and symtomatic bacteriuria were monitored. Adverse side effects were determined by questioning the patients about signs of rash, vomiting, diarrhea, nausea, irritation, or discharge. Cultures were taken to identify vaginal yeast and other potential pathogens.
Results
The most commonly isolated organisms were Escherichia coli (65%), followed by coagulase-negative staphylococci (15%), coliforms (13%), Klebsiella sp (5%), and Proteus sp (2%). All the organisms cultured were susceptible in vitro to norfloxacin and TMP/SMX. The three day norfloxacin therapy was marginally more effective than TMP/SMX (100% vs 95%) in eradicating UTI from the bladder; however, the difference was not statistically significant. Only one patient was removed from the study because of no growth of bacteria from the urine culture. No side effects were reported by or recorded for any other patients, nor did any patients show evidence of superinfection.
Six patients decided not to take suppositories because their infections had been cleared and they felt well. Two patients failed to return for their five-week appointment due to university exams and travel problems, and one patient dropped out of the study due to an unrelated pneumoniae. One woman moved out of the province and could not make the six month appointment. Overall, 31 of the original 41 patients complied well with the study regimen.
TABLE 1______________________________________Rates of eradication and recurrence of urinarytract infection (UTI) by type of therapy No. of UTI UTITherapy Patients* Eradication Recurrences†______________________________________Norfloxacin 20 20 (100%) 4/14 (29%)Plus lactobacilli 6 2(10)Plus placebo (10) 8 2Trimethoprim/ 20 19 (95%) 7/17 (41%)sulfamethoxazolePlus lactobacilli 8 1(9)Plus placebo (11) 9 6______________________________________ *All 40 patients were evaluated for eradication of UTI but nine did not return for longterm followup and so could not be included in recurrent UT analysis. †Net recurrence rates: with lactobacillus, 21%; with placebo, 47% (P = 0.27).
As shown in Table 1 above, the symptomatic UTI recurrence rate for norfloxacin-treated patients was 29% and for TMP/SMX treated patients was 41% (P=0.77, chi-square). In addition, one asymptomatic infection was detected. Only one patient had more than one infection (two detected) during the study. Recurrences of UTI were treated with a three-day course of norfloxacin. Recurrences for lactobacillus treated patients occurred at two weeks (one patient) and at three months (two patients), giving an overall recurrence rate of 21%. In comparison, patients given skim milk suppositories experienced a recurrence rate of 47% with recurrences at two weeks (three patients), five weeks (one), two months (two), and six months (two) (P=0.27, chi-square). The causative organisms in the recurrences were E. coli (nine), coagulase-negative staphylococci (one), and enterococci (one). Lactobacilli were absent from the vaginas of 50% of the patients upon entry into the study. Treatment with lactobacilli resulted in a threefold increase in lactobacillus counts. Some patients who received specially prepared skim milk suppositories had an increase in their lactobacillus counts following therapy (e.g. 4.4×10 5 /ml lactobacilli in a vaginal swab specimen upon entry, 1.2×10 6 /ml after two weeks, and 9.6×10 6 /ml after two weeks, and 9.6×10 6 ml after five weeks), showing the ability of this agent to stimulate the patients' own lactobacilli.
The present study supports the prior art finding that norfloxacin and TMP/SMX are effective in eradicating acute, uncomplicated cystitis. In this study, the organisms causing recurrences were typical uropathogens, suggesting that suppositories did not induce infection by less common isolates. Patient compliance with the study regimen was fairly good, considering that the patient population comprised university students whose follow-ups were often dictated by exam schedules and departure from campus to return to homes outside Toronto. Indigenous lactobacilli were present in the vaginas of patients who received TMP/SX therapy followed by specially prepared skim milk suppositories.
The use of lactobacillus suppositories was well received and although only a small dosage was given, patients experienced a low rate of recurrence of UTI, without side effects or candidal superinfection. The current alternative for patients with recurrent UTI is daily doses of antimicrobial agents, sometimes for as long as five years. The use of daily doses of antimicrobial agents, especially TMP/SMX, to kill or inhibit the growth of uropathogens is effective and is used by most urologists; however, with this treatment some breakthrough infections can occur, drug resistant pathogens can emerge, and lengthy patient compliance is required.
The present study was not designed to compare lactobacillus suppositories with prophylactic TMP/SMX. The sample size was not chosen for efficacy. However, the study does not show the safety of the approach, an acceptable degree of effectiveness with limited therapy, and a particular potential for combined use with TMP/SMX. This regimen would be useful for many women, as it is known that certain antimicrobial therapy can disrupt the urogenital flora for several weeks and can even induce recurrences of UTI.
It is anticipated that in some patients, twice weekly lactobacillus or skim milk or LGF therapy may be needed to achieve a protective flora.
Occasionally, the virulence of uropathogens and the extent of their urogenital colonization will require extended antimicrobial therapy to eradicate the infecting bacteria and provide lactobacillus with an opportunity to potentially protect the patient.
Thus, both methods offered a degree of protection for the patient, without any side effects, especially the lactobacillus.
EXAMPLE 2
A randomized, controlled clinical trial was carried out to compare the use of lactobacillus vaginal supplementation with the use of a LGF to reduce the incidence of uncomplicated, lower urinary tract infections (UTI) in adult, premenopausal women.
Materials and Methods
Patients
Fifty five healthy women, aged 22 to 49 years (mean 34±6), were accrued, having signed a voluntary consent form approved by the Health Review Board of the Toronto General Hospital.
Entry Criteria and Pre-Trial Work-Up
The entry criteria were: (i) a history of at least 4 UTI in the past 12 months, with each one having symptoms and requiring antibiotic therapy, and with at least two being documented by cultures (≧10 5 organisms/ml mid stream urine), or alternatively, be receiving long term (≧3 months) low dose antibiotic therapy to prevent recurrences of UTI, and have had one positive culture prior to starting the study; (ii) a full urological work up to ensure there was no urinary tract abnormalities. This included urine culture and sensitivity, KUB X-ray, ultrasound of abdomen or intravenous pyelogram, cystoscopy and uroflow plus ultrasound (within 12 months of entry). The urogenital flora was also cultured for baseline lactobacillus counts. In addition, the presence of a sexually transmitted disease (bacterial, viral, chlamydia) was ruled out by culture. Patients with sterile urine were entered into the study.
Patients were excluded if they had abnormal renal function (serum creatinine ≧110 umol/l, upper limit 90 umol/l) and /or pyelonephritis, diabetes mellitus, abnormal serum glucose, a neurogenic bladder, if their antibiotic therapy could not be discontinued, or if they were on prednisone or immunosuppressive drugs.
Sample Size and Justification
Based upon the analysis of past data on symptomatic, culture-confirmed UTI in 26 women meeting study eligibility criteria, it was decided that a clinically significant reduction of 50% would require a sample size of 28 patients in each arm of the study. This included an allowance for a nonparametric analysis (Wilcoxon Sum Rank Test) requiring a further 16% increase in sample size, and allowance for up to 20% drop-out, loss to follow-up etc. Randomization was stratified by 8 or more UTI per year and those with 4 to 8 per year, and also by long term antibiotic use. The purpose was to try to get balanced treatment allocation among variables that may correlate with outcome. Whilst the numbers were small for subgroup analysis, the information was deemed useful to obtain.
Preparation of Lactobacillus and LGF Suppositories
Two known in the art Lactobacillus strains L. casei var rhamnosus GR-1 and L. fermentum B-54 were selected wherein the relatively hydrophillic GR-1 and hydrophobic B-54 had been shown to be well adherent to uroepithelial cells, to block to some degree adhesion by uropathogens, to produce inhibitory substances against E. coli and Enterococcus faecalis, to resist some antimicrobial agents and nonoxynol-9, and to form coaggregates similar to those found in the vagina of healthy women.
The organisms were inoculated from frozen (-70° C.) culture vials onto Lactobacillus MRS agar, an enriched medium. Following 48 hours culture at 37° C. in 5% CO 2 , the organisms were checked for purity and subcultured into 3 ml MRS broth then 25 ml broth for another 2×24 hours. Finally, the cultures were grown in batch MRS broth to obtain sufficient yields for the study, then the organisms were washed in sterile saline, suspended in sterilized skim milk powder and freeze dried. The lyophilized bacteria were checked for purity and potency monthly for the duration of the study. The purity was maintained and the potency was found to over 1×10 9 viable organisms per vial. The organisms were dispensed into 0.5 g aliquots in size 00 gelatin capsules. The capsules were transferred to the Pharmacy Department at the Toronto General Hospital, where they were stored at 4° C. and distributed to individual patients in a randomized manner to which the principal investigators were blinded.
The LGF was suspended in distilled water, autoclaved, then freeze dried and dispended as 0.5 g aliquots into size 00 gelatin capsules.
The research nurse instructed the patient on how to insert the suppositories into the vagina. The procedure was carried out prior to going to bed at night, and at weekly intervals for 12 months. During menstruation, the patient did not insert a suppository but recommenced the application immediately following menses. The patient was instructed not to have intercourse on the night of suppository insertion.
Follow-up, Outcome Measures and Measurement of Compliance
Patients were seen in follow-up visits within the first two weeks of commencing therapy, and at the end of each month. The visits were arranged, where possible, seven days after insertion of a suppository. At each visit, the following procedures were performed: (i) a mid-stream urine sample was provided for culture, (ii) a vaginal swab and pH measurement were taken by the nurse and lactobacillus numbers measured by semi-quantitative culture and adherence per 50 gram stained epithelial cells, (iii) the suppository vial was returned to assess compliance, (iv) the patient's diary was inspected and the patient questioned about compliance, side effects, symptoms, antibiotic therapy or other improved or adverse effects to her health, and (v) another suppository vial was dispensed by the Pharmacy.
If the patient developed symptoms or UTI (urgency, frequency, dysuria, pyuria, suprapubic discomfort), she provided a mid-stream urine sample, preferably first morning, in a sterile container. She placed a Multistix strip (Ames) and dip-slide (McConkey's and blood agar) into the urine, as previously instructed, and read a positive result of the former by colour changes representing leukocytes (purple) and nitrites (pink) indicative of uropathogenic infection. She also took a vaginal specimen and sent the samples for immediate culture. Infection was confirmed with the finding of ≧10 5 single species of gram negative bacteria or ≧10 4 single species of gram positive cocci per ml urine. The patient instituted three days of antibiotic therapy (norfloxacin 400 mg×2 or an alternative). If the culture turned out to be negative or with insignificant counts, the nurse recorded the results as institution of antibiotic therapy without infection. The infected patient was instructed to commence suppository insertion immediately after antibiotic use, and to send a urine sample for culture within one week to ensure eradication of infection. If the patient continued to have symptoms, along with bacteriuria upon one week follow-up, she ceased suppository use and was given 7-10 days antibiotics, based upon sensitivity to a drug. Lactobacillus or LGF therapy was commenced immediately upon completing use of the drugs.
If an episode of asymptomatic bacteriuria (≧10 5 uropathogenic bacteria per ml mid-stream urine) was detected upon routine monthly check-up, the patient was asked to self test her urine twice daily with a Multistix dip-strip. If there was a persistent positive result over one week confirmed by one additional culture, antibiotic administration was initiated and she followed the protocol for symptomatic infection.
Results
The drop out rate for the study was as predicted (22%), and the total patient accrual was also as expected (24 in LGF and 25 in lactobacillus group). Only six of the fifty five patients were excluded within the first two weeks of study due to never having complied (4) and being found to be pregnant within the first two weeks of study. (2) Eleven patients did not complete the full 12 month study due to recurrences of UTI (4), moving home (4), pregnancy later in the study (2) and receiving other therapy (1).
The results are shown in Table 2 below:
TABLE 2______________________________________The results for the clinical study oflactobacillus and LGF treated patientsLactobacillus Treated LGF TreatedPrev Study Symp Prev Study SympPat# UTI LTT Time UTI Pat# UTI LTT Time UTI______________________________________101 5 N 51 1 103 4 Y 52 1102 4 Y 52 0 104 7 Y 52 0107 4 N 52 1 105 4 Y 52 1108 4 N 55 2 106 4 N 52 2112 7 N 52 0 109 4 N 52 0113 4 N 51 1 110 4 Y 54 0118 4 N 53 0 114 5 N 52 0122 6 Y 52 4 117 5 Y 54 1124 5 Y 52 0 119 4 N 52 4125 4 N 52 0 121 4 Y 52 0129 4 N 53 4 123 4 N 52 1205 12 Y 54 3 127 4 Y 53 0206 8 N 52 5 128 6 Y 54 1210 6 Y 52 0 130 6 Y 53 1219 7 Y 52 4 141 4 Y 52 1349 4 N 52 0 202 8 Y 52 0351 8 Y 52 1 207 7 Y 52 2 208 12 Y 53 0 215 8 N 56 1 217 12 N 53 2 301 4 N 54 2Did not complete study:111 5 N 39 1 211 4 Y 16 1116 4 N 20 1 216 12 N 15 2126 4 Y 19 0 396 8 Y 12 0204 10 N 32 3212 6 Y 17 4214 7 Y 35 2218 12 Y 16 1382 6 Y 16 3______________________________________ Pat# = patient identification number; Prev UTI = number of UTI in previous 12 months; LTT = patient on long term therapy (Y) or not on long term therapy (N) upon entry to study; Study Time = in weeks; Symp UTI = number of symptomatic urinary tract infections during the study.
The primary objective of the study was to examine how many UTI recurrences occurred with the two therapies. The results showed that very few (26) recurrences of UTI occurred over one year in a group of 17 lactobacillus treated patients who completed the trial, and 20 UTI's occurred in the LGF group. There was no statistical difference between the incidence of acute, symptomatic UTI per year in the lactobacillus treated group of 25 patients compared to the 24 who were treated with LGF suppositories (p=0.686). There was also no statistical difference with respect to the mean number of asymptomatic infections between the two groups (1.0 UTI per year for lactobacillus patients, 0.6 for LGF: p=0.357). There was a substantial decrease in the symptomatic UTI rate compared to the previous 12 months, for patients given lactobacilli (73.1% reduction) and those given LGF (81.1%). This translated into an average of 1.9 and 1.0 UTIs per year per patient in the lactobacillus and LGF treated groups respectively compared to 5.6 and 6.0 respectively for the previous year. In the combined group, most (67%) patients had 0-1 infections per year, while a subgroup of 6 women (12%) acquired 4 or more of the infections recorded.
Of the patients given lactobacillus, 12 had been on long term antibiotic therapy and they subsequently acquired 22 UTI on study compared to 19 UTI in the other 13 patients who had not been on long term antibiotic therapy (p=0.966). In the LGF treated group, 15 patients had previously been on antibiotic prophylaxis and they acquired 9 UTI (versus 14 UTI for the other 9 patients previously not on antibiotic prophylaxis).
Dipsticks were used to detect infections at home and in the clinic. Of a total of 524 tests, the dipsticks were found to give a true positive result confirmed by culture in 100/111 (90%) of cases, and a true negative result confirmed by culture in 225/413 (54%) of cases. This translated into a sensitivity of 35% (100/288) and specificity of 95% (2225/236).
The recurrences of UTI were caused by standard uropathogens: E. coli (57%), streptococci (including E. faecalis (16%), Klebsiella 10%, staphylococci (10%), coliforms (3%), Enterobacter (2%) and Proteus (2%).
The vaginal pH was found to range from 3.5 to 7.5 over the study, with mean monthly values of 4.6 to 5.0 for the lactobacillus treated patients and 4.6 to 5.0 for the LGF treated group (no statistical difference between the groups).
The Lactobacillus semi-quantitative viable counts from vaginal swabs were monitored prior to and during study.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows the mean values for lactobacillus colonization and demonstrates that supplementation with L. casei GR-1 and L. fermentum B-54 and the use of LGF led to an increased viable count of lactobacilli from the baseline level every month throughout the study (except for month 4, p≦0.5).
Although not statistically significant, there was a trend towards higher numbers of lactobacilli in the patients treated with GR-1 and B-54 than in the LGF treated group, especially after 7 months. The lactobacillus viable count for the patients given GR-l/B-54 therapy showed a trend (p=0.061) towards being greater during the second six months of the study, compared to the first six months. In addition, the symptomatic infection rate was lower during the last six month period when lactobacillus numbers were elevated (P=0.232). Colony morphology and gram stain analysis by the technician (using a blinded numbering system) showed that GR-1 and B-54 could be correctly differentiated from other lactobacilli in 76% of the specimens from patients given suppositories containing these organisms. It was evident that throughout the course of the study, GR-1 and B-54 were indeed present and viable every week after insertion.
The analysis of lactobacillus adhesion counts per vaginal epithelial cell showed no difference between the two groups for all samples tested (14 per cell for the lactobacillus treated versus 13 per cell for LGF treated). However, for the lactobacillus treated group, there were twice as many adherent lactobacilli present in patients with 0-1 UTIs per year compared to those with ≧2 UTIs per year (mean 17 adherent per cell versus 9). A comparison of the adherence and viable count data showed that values between 0 to 9 bacteria per cell corresponded to viable counts with a mean 2.5×10 6 , while values ≧17 per cell corresponded to viable counts of 4.8×10 6 , indicating a degree of correlation.
The primary analysis showed there to be no difference between the infection rates between the two treatment groups. Rather than suggest that the lactobacillus group showed no effect on the infection rate, there are many findings which indicate that the two modes of therapy did protect the patients. The entry criteria did not require the close patient scrutiny and UTI confirmation that occurred during the study, and therefore the infection rate for the past 12 months is just as likely to be higher as it is lower (for example, asymptomatic or symptomatic UTI may have occurred without being recorded). The infection rate during study was extremely low (1.9 and 1.0 per patient per year respectively for the lactobacillus and LGF groups) for such a high risk group of patients. This rate includes a subgroup of 6 patients who experienced 4 or more UTIs per year.
Twenty seven of the patients had been on long term antibiotic therapy. A prior art study was carried out with similar inclusion criteria to the present one, to investigate whether three antimicrobial regimens reduced the recurrence rate for UTI in 67 women. (Brumfitt, W., Hamilton-Miller, J. M. T., Gargon, R. A., Cooper, J., Smith, G. W., 1983. Long-term prophylaxis of urinary infections in women: comparative trial of trimethoprim, methenamine hippurate and topical povidone-iodine. J. Urol 130: 1110-1114.) Using the same method as here to determine the decrease in the infection rate from the previous year, the study found there to be 2.3 infections per year using nightly trimethoprim (100 mg), 2.4 per year using a povidone-iodine perineal wash and 2.0 per year using 1,000 mg methanamine-hippurate every 12 hours. Twenty three per cent of patients dropped out prematurely from the antimicrobial study and side effects of nausea, vomiting, gastrointestinal reactions and vulval rash were reported. Although only one mild occurrence of a side effect was reported using trimethoprim, there was an 82% resistance rate in organisms taken from patients treated with this antibiotic. Clearly, the present trial stands up well with that antimicrobial study, with no side effects, no drug resistance and lower rates of UTI recurrence.
It did appear that the instilled lactobacilli survived and grew in the urogenital tracts of the patients, based upon the morphological identification of strains GR-1 and B-54 from vaginal cultures and cells, and from the increased lactobacillus colony counts following suppository insertion. This is an important ecological finding, as some scientists have questioned whether or not implanted organisms could survive in the host. From FIG. 1, it would appear that the colonization level increased during the second six month period of the study, particularly in the lactobacilli treated patients. This coincided with a reduced infection rate. Whether this finding means that the inserted lactobacilli took several months to become fully established remains to be verified.
One of the criteria for selecting strains L. casei var rhamnosus GR-1 and L. fermentum B-54 was their known adhesiveness to uroepithelial cells in vitro (64 and 39 bacteria per cell, respectively). Clearly, the levels of adhesion found in vivo were much lower. This could have been due to their freeze dried status when implanted, to the difference in nutrients available compared to the in vitro assays, to a difference in receptor sites between the sloughed uroepithelial cells and vaginal cells, or reasons unknown. Similar discrepancies have been found for uropathogenic E. coli adherence in vivo and in vitro. A previous clinical study (Bruce et al., "Preliminary study on the prevention of recurrent urinary tract infection in adult women using intravaginal lactobacilli", Int Urogynecol J (1992)3:22-25) using intravaginal lactobacilli showed that an adhesion count greater than 4 bacteria per cell correlated with viable counts greater than 100,000 lactobacilli. In the present study, there was clearly substantial in vivo colonization: if each cell has 17 adherent lactobacilli, then only 2.82×10 5 cells would need to be coated to correspond to 4.8×10 6 viable organisms. This is not an unrealistic expectation considering that this number of vaginal cells, side by side, would only cover a 3 cm 2 surface area. Alternatively, the organisms could be colonizing the vaginal mucus and not be adherent to cells.
An interesting secondary finding was the very low (35%) sensitivity and very high (95%) specificity of the leukocyte nitrite dipsticks for detection of bacteriuria. This indicates some degree of use in the specificity of this quick method to determine whether or not a patient is suffering from UTI, but it also showed there are serious limitations to the sensitivity of the results.
There was no statistically significant difference in the infection rate for the two groups over the study. Based upon the UTI rate for the previous 12 months, there was a net 73.1% reduction in the symptomatic infection rate for patients given lactobacilli, and 81.1% reduction for those patients whose indigenous flora was stimulated with LGF. Most of the recurrences occurred in a small group of patients and all were caused by common uropathogens, with E. coli being responsible for 57%. No significant side effects arose during the study. The lactobacillus viable counts in the vagina were higher than the pretrial baseline values for both groups, but especially after 7 months lactobacillus therapy. There were twice as many adherent lactobacilli per vaginal epithelial cell for patients with 0-1 UTIs per year compared to those with 2 or more per year. In summary, this example shows that recurrent UTI can be reduced in high risk patients using the two new prophylactic measures tested.
EXAMPLE 3
In order to confirm that LGF had a specific role in stimulating the indigenous lactobacillus flora of patients, a study was carried out on 13 healthy adult female volunteers. Their indigenous lactobacillus count was measured by swab and culture and taken as a baseline figure. Then, a single LGF vaginal suppository was administered and the patients returned one week later for vaginal swab and culture. The results shown in the Table 3 below demonstrate very clearly the significant impact (81.4% increase) of the therapy on the protective lactobacillus flora.
TABLE 3______________________________________The results of lactobacillus vaginal countsafter treating 13 women with a single speciallyprepared suppositories containing lactobacillusnutrients. In all 13 specimens, thelactobacillus total vaginal count increased bya percentage means of 81.4 ± 19.7 over one week.Patient Lactobacillus Viable Counts per ml PercentageNumber Prior to Treatment After Treatment Difference______________________________________1 5,000 361,000 +99%2 7,000 132,000 +95%3 6,000 165,000 +96%4 6,800 34,000 +80%5 1,000 28,000 +96%6 1,800,000 2,880,000 +38%7 25,300 50,000 +49%8 700,000 5,000,000 +86%9 6,500 256,000 +97%10 70,000 370,000 +81%11 180,000 6,200,000 +97%12 4,000 9,000 +56%13 2,000 17,000 +88%______________________________________
EXAMPLE 4
The application further supports an earlier finding in 10 women who were given the lactobacillus suppositories once or twice weekly for over one year (Bruce et al., supra). In that group, there was a net resultant reduction in bladder infection rate of 77.3%. This is again a highly significant result and provides strong support for the claims, especially as the strains have been shown to possess specific hydrophobic and hydrophillic properties and produce cellular and extracellular adhesins. In this latter study, the adhesion of lactobacillus had to achieve ≧10 5 organisms per ml when a mucosal tissue swab was taken and suspended for culture. The use of different dosages was found to depend upon the patient's receptivity for lactobacilli, with more than one weekly treatment sometimes being required. Again, no serious side effects were found.
EXAMPLE 5
The characteristics of the lactobacillus are most important for their selection. The first is their ability to colonize surfaces. The organisms can achieve this through hydrophobic and hydrophillic mechanisms of binding to biomaterial (catheters, prosthetic devices) and cell (intestinal, vaginal, uroepithelial) surfaces. Hydrophobicity can be well measured using a technique called contact angle with water. The higher the angle, the more hydrophobic the organism. The testing of 23 strains, as shown in Table 4 below, has shown that the contact angle should be >19 degrees for lactobacillus to have adherence characteristic potential.
TABLE 4______________________________________ WaterAdhesive Lactobacilli Contact Angle______________________________________L. acidophilus 68 74 75 66 RC-14 102 T-13 80L. casei 55 36 8 30 43 46 36 19 62 19 65 58 70 43 ATCC 7469 34 RC-15 52 RC-17 54 GR-1 33 81 86L. fermentum A-60 29 B-54 105L. gasseri 56 90 60 67L. jensenii RC-28 87L. plantarum RC-6 25 RC-20 79______________________________________
EXAMPLE 6
The adhesion of lactobacillus to cells is not a new finding, as we have shown in our 1987 J. Urology paper (Reid et al., "Examination of strains of lactobacilli for properties that may influence bacterial interference in the urinary tract", J. Urol., 138:330-335, 1987), nor is their adhesion to biomaterials, as we have shown in our 1988 Microbial Ecology paper (Reid et al., "Adhesion of lactobacilli to polymer surfaces in vivo and in vitro", Microb. Ecol. (1988) 16:241-251). However, adhesion per se is not sufficient, as in vitro experiments do not adequately reflect in vivo quantitative situations. This is shown from our clinical study of 10 patients where adhesion per cell varied from 0 to 45 per cell. Thus, the documentation of adhesion in vitro does not necessarily demonstrate that the bacteria will be adherent in vivo. This means that other adhesion characteristics are of importance and the models we test them on must be more realistic and utilize actual human cells in monolayers and commercially used catheters or devices that are in place within the urinary tract. To that end, lactobacilli have been found to adhere (>1000 per cm squared) to urinary catheters depending upon their own hydrophobic/hydrophillic properties. In addition, using human intestinal Caco-2 and HT-29 cell lines, lactobacilli (strains RC-17, RC-14, RC-20 and others) were found to adhere highly (often >60 bacteria per cell). Because uropathogenic organisms emerge from the intestine, lactobacillus should be used to compete with these within the intestine, thereby lowering the risk of the pathogens infecting the urogenital tract. It should be noted that this application can apply to males and females. This latest finding represents a different and not obvious use of lactobacillus implantation into the intestine. It also shows the colonization ability of strains to in vivo cells.
In addition, the mechanisms of adhesion for lactobacilli to the intestinal epithelial cells was via a non-proteinaceous cell wall adhesion, and especially a trypsin sensitive adhesion in the cell supernatant, i.e. produced by the cells. This is a new finding, and stresses that cell supernatants should be used in therapeutic regimens.
Adhesion of lactobacilli to biomaterial surfaces was found to be mediated by hydrophobic and hydrophillic mechanisms, again a novel discovery.
EXAMPLE 7
The ability of the lactobacillus to resist nonoxynol-9 is one characteristic that is of general importance. However this property does not improve adhesion, thus it is not a vital component of the successful selection of the organisms. The key to having lactobacilli resistant to nonoxynol-9 is that for patients who administer nonoxynol-9 (contained within a spermicide) used as an adjunct to a condom or other contraception, the installation of lactobacillus will be vital to balance the flora. Our previous studies (McGroarty et al., "Influence of the Spermicidal Compound Nonoxynol-9 on the growth and adhesion of urogenital bacteria in vitro", Current Microbiology, Vol. 21 (1990), pp. 219-223) have shown that nonoxynol-9 usually kills lactobacilli and allows urogenital bacterial and fungal pathogens to grow and potentially dominate the flora and infect the patient. The selection of lactobacilli that resist nonoxynol-9 has now been developed and tested in the three clinical studies described above. There are no adverse effects of using nonoxynol-9 resistant strains, but the patient using this spermicidal compound will likely have fewer urogenital infections. This acts as an example of the benefits of resisting the action of an antimicrobial agent.
EXAMPLE 8
Unlike other definitions of lactobacillus for human use, we have found the production of inhibitory substances, such as hydrogen peroxide, need not be essential for effectiveness. In a study of over 150 normal women and women with a history of recurrent urogenital (yeast and bacterial) infections, we found that hydrogen peroxide producing lactobacilli were isolated from either group, thus showing that this inhibitory substance does not play a major role in defending the host against infection. This study also isolated and speciated strains from women, and demonstrated the species of lactobacillus which form the flora of the urogenital tract and make possible claims 3, 8, and 16.
EXAMPLE 9
Of over 150 strains in our collection, most show an ability to resist more than one antimicrobial agent. In the case of vancomycin resistance, this appears to correlate to some extent with hydrophillic surface properties and nonoxynol-9 resistance, as shown in Table 5 below. Thus, the surface components that confer adhesiveness also impart resistance to antimicrobial agents. This represents a novel finding.
TABLE 5______________________________________Hydrophobicity of lactobacilli and relationshipwith susceptibility to vancomycin and nonoxynol-9 Contact AngleStrain (Degrees) Vancomycin Nonoxynol-9______________________________________L. casei 55 36 S SL. gasseri 60 67 S SL. acidophilus 68 74 S SL. acidophilus 75 65 S SL. plantarum RC-20 79 S SL. casei RC-15 52 S SL. jensenii RC-28 87 S S Mean 66 ± 15L. casei 8 30 R RL. casei 70 43 R RL. casei GR-1 33 R RL. casei 36 19 R RL. casei 62 19 R RL. casei 65 58 R RL. plantarum RC-6 25 R R Mean 32 ± 13______________________________________ R = resistant, S = susceptible Mean of 66 is significantly greater than 32 (Chisquared test, p < 0.001).
In order for lactobacillus to survive and continue to protect the host, it is important that these organisms possess antimicrobial activity, particularly against co-trimoxazole, the most commonly used antimicrobial agent against bladder infection. Resistance to co-trimoxazole has been documented in our studies. The testing of 125 lactobacillus strains showed resistance to one or more antimicrobial agents. Table 6 below is an example of antimicrobial susceptibility patterns:
TABLE 6__________________________________________________________________________EXAMPLE OF ANTIMICROBIAL SUSCEPTIBILITY PATTERNS__________________________________________________________________________ ##STR1## ##STR2##__________________________________________________________________________ NOTE: THE ANTIBIOTICS USED WERE AMPICILLIN(AM), AMIKACIN(AN), CHLORAMPHENICOL(C), CLINDAMYCIN(CC) CEPHALOTHIN(CF), ERYTHROMYCIN(E), TOBRAMYCIN(NN), PENICILLIN(P), STREPTOMYCIN(S), SULFAMETHOXAXOLE/TRIMETHOPRIM(SXT), TETRACYCLINE(T), VANCOMYCIN(V). ##STR3##
EXAMPLE 10
The use of lactobacillus within a skim milk powder or LGF base in a gelati suppository results in a stable preparation >1000M viable organisms per 0.5 g over 12 months.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
The following microorganisms were deposited in the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md. 20852: Lactobacillus casei var rhamnosus, GR1, ATCC 55826 on Oct. 3, 1996; Lactobacillus casei var rhamnosus, RC17, ATCC 55825 on Oct. 3, 1996; Lactobacillus casei, RC36, ATCC 55841 an Oct. 25, 1996; Lactobacillus plantarum, RC20, ATCC 55883 on Nov. 26, 1996; Lactobacillus fermentum, B54, ATCC 55884 on Nov. 26, 1996; Lactobacillus acidophilus, RC14, ATCC 55845 on Oct. 25, 1996; Lactobacillus gasseri 60 on Oct. 25, 1996, ATCC 55844; and Lactobacillus jensenii, RC28, ATCC 55918 on Dec. 19, 1996.
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This invention relates to lactobacillus, skim milk, lactobacillus growth factor (LGF) and lactobacillus compositions and methods of employing said composition for preventing urogenital infections. More particularly, this invention relates to the ability of strains of hydrophobic or hydrophilic lactobacillus to adhere to biomaterials, intestinal, vaginal and uroepithelial cells, to resist the action of certain anti-microbial agents and to dominate the urogenital flora.
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RELATED APPLICATION
[0001] This application claims the benefit of the filing date under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 60/429,811, filed Nov. 27, 2002, the entire contents of which is incorporated herein by reference.
BACKGROUND
[0002] The present invention relates generally to a window assembly. More specifically, the invention relates to a window guard to protect an edge in an opening of a window.
[0003] A primary function of sliding window assemblies in vehicles is to provide ventilation for, e.g., the passenger compartment of the vehicle equipped with such an assembly. However, it is not uncommon for users to take advantage of the open window as a pass through for supporting lengthy cargo, thereby minimizing rearward extension of the cargo, e.g., into and/or beyond the bed of a truck having a backlight equipped with such a sliding window assembly. The force exerted by resting cargo on the exposed edge of the window causes abrasion and/or impact which may be a cause for concern.
[0004] While the primary functional purpose of such a sliding window assembly in a vehicle is primarily intended for ventilation, it is not uncommon for users to take advantage of the window as a pass-thru opening for supporting lengthy cargo and thereby minimize rearward extension of the cargo outside the vehicle. The downward force exerted by resting such cargo on the exposed edge of the window opening should, in most cases, not be of major concern by itself, since the compressive strength of glass is generally quite good. However, lateral forces (fore & aft), abrasion, and/or impact forces resulting from such cargo resting on the glass could be of concern.
[0005] From the above, it is seen that there exists a need for protection of certain exposed edges in a window opening.
BRIEF SUMMARY OF THE INVENTION
[0006] In overcoming the above mentioned and other drawbacks, the present invention provides a window assembly, such as the slider backlight assembly commonly found on pick-up truck vehicles, having a fixed window with an opening, a slidable panel that slides relative to the fixed window to cover or expose the opening in the fixed window, and a covering to protect the lower edge of the window opening.
[0007] The covering may be a protective sheet attached at one end to a lower member or portion of the window assembly. The other end remains unattached so as to create a flexible flap of material. When needed, the protective cover is simply placed over the exposed bottom edge of the opening to protect the edge from damage by objects resting on the edge, and when not in use the cover is allowed to hang freely or otherwise fastened out of the way below the window opening. The protective material could be suitably colored and textured to coordinate with adjacent interior trim materials. The covering is a flexible, durable sheet.
[0008] The fixed end of the covering may be attached to the interior or exterior of the fixed window with a suitable connection means. Various attachment means, both permanent and releasable, can be used to secure the cover in place. The cover may be a substantially U-shaped clip that covers the edge in a removable manner.
[0009] Further features and advantages will become apparent from the detailed description and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings, incorporated in and forming a part of the specification, illustrate several aspects of the present invention. The components in the figures are not necessarily to scale, emphasis instead being placed on illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings:
[0011] [0011]FIG. 1A is a back view of a sliding window assembly in an open position with a protective edge cover flap in accordance with an embodiment of the invention.
[0012] [0012]FIG. 1B is a perspective view of a portion of the sliding window assembly.
[0013] [0013]FIG. 2 is a perspective view of a portion of a sliding window assembly in an open position with a protective edge cover flap in accordance with another embodiment of the invention.
DETAILED DESCRIPTION
[0014] [0014]FIGS. 1A and 1B depicts a sliding window assembly 10 with a fixed panel 12 and a slideable panel 14 . In one example, the panels 12 and 14 are both of glass and are used as part of the backlight assembly of a vehicle, e.g., a pickup truck. Alternatively, either panel 12 or 14 or both can be made from a plastic. In operation, the slideable panel 14 slides back and forth relative to the fixed panel 12 along a pair of rails 13 so that a user, such as the driver or passenger, can move the panel 14 between an open position and a closed position.
[0015] In accordance with an embodiment of the invention, the window assembly 10 is also equipped with a protective edge cover 16 placed over an otherwise exposed edge 18 of an opening 20 in the fixed panel 12 . The edge cover 16 can be a detachable. In the embodiment illustrated in FIGS. 1A and 1B, the edge cover 16 is a “U”-shaped clip of rubber (or some other suitable durable material) that fits snugly over the edge 18 . Thus, the U-shaped cover 16 can simply be inserted over the edge 18 of the panel 12 , and thereby isolate or insulate the exposed edge 18 of the panel 12 from direct contact with cargo that might come to rest on the edge of the glass when the sliding panel 14 is in the open position. When the protective function of the cover 16 is not desired, the user removes the cover 16 by simply pulling the cover 16 away from the edge 18 , and the user can then move the sliding panel 14 to the closed position and lock the sliding panel in place with a pair of latches 15 that mate with a pair of attachments mechanisms 17 on the panel 12 .
[0016] In its closed position, the slideable panel 14 covers the opening 20 in the fixed panel 12 . In its open position, the slideable panel is moved to the side to uncover the opening 20 . A user may then place cargo in the bed of the truck such that the cargo extends through the opening 20 into the cab of the truck and rests on top of the cover 16 . As mentioned above, the cover 16 functions as a protective cover for the lower edge 18 of the opening 20 . Accordingly, the edge 18 is protected from impact forces and abrasion from the cargo extending through the opening 20 . Thus, the user can place cargo on the edge 18 , for example, the lower edge of an opening in a sliding glass backlight assembly of a pickup truck, without concern for damaging the panel 12 .
[0017] Referring now to FIG. 2, the cover 16 can be a protective sheet integrated into the design of the window assembly 10 . In this configuration, the cover 16 cannot become separated and lost or displaced.
[0018] The cover 16 can be equipped with attachment features, for example, protrusions or snaps, which mate with attachment features formed on the fixed panel 12 or on the support structure in which the fixed panel 12 is mounted.
[0019] The attachment features of the cover 16 are releasable from those on the fixed panel 12 or the nearby support structure of the cab in which the fixed panel is mounted. The attachment features can be configured for attaching the cover 16 either to the inside or outside of the fixed panel 20 or to both sides.
[0020] In one implementation, the cover 16 has one end 22 coupled, for example, to the fixed panel 12 or the support structure for the fixed panel 12 by a hinge, adhesive, screw, or other suitable fastening mechanism 23 . The other end 24 of the cover 16 is equipped with a releasable fastening feature 26 , for example, a snap, hook and loop fastener, latch, or Velcro and the panel 12 or support structure is equipped with a corresponding fastener feature 28 located on the opposite side of the panel 12 from the fastening mechanism 23 . The fastener feature 28 mates with the fastening feature 26 in a releasable manner.
[0021] To use the cover 16 , the user pulls the end 24 of the cover 16 and extends it through the opening 20 to cover the edge 18 . The user then secures the fastening features 26 with the respective fastening features 28 to hold the cover 16 in place.
[0022] The implementation shown in FIG. 2 can be configured with the fixed end 22 coupled either to the outside or inside of the panel 12 . Thus, in certain arrangements, the protective edge cover flap 16 can be pulled from outside the cab, and in other arrangements, the cover 16 is pushed from inside the cab through the opening 20 .
[0023] While the above description contains specificities, these should not be construed as limitations on the scope of the invention, but merely as examples of the presently preferred embodiments. Other variations are possible within the teachings of the invention. For example, the protective material of the cover 16 can be made from polyurethane, or polyvinyl and Kevlar, or any other suitable abrasion resistant material. The cover 16 can have any suitable thickness that isolates impact forces from being imparted on the bottom edge of the panel by the cargo. Moreover, the protective material can be suitably colored and textured to coordinate with passenger compartment trim materials.
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The present invention provides a window assembly having a fixed window with an opening, a slidable panel that slides relative to the fixed window to cover or expose the opening in the fixed window, and a covering to protect the lower edge of the window opening.
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RELATED APPLICATION
[0001] This application claims benefit of provisional application attorney docket No. 2316.2323USP1, entitled FIBER ACCESS TERMINAL INCLUDING MOISTURE BARRIER PLATE, filed Jan. 4, 2006, the disclosure of which is incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates generally to provision of optical fiber telecommunications service. More specifically, the present invention relates to a fiber access terminal and a method of using a fiber access terminal.
BACKGROUND
[0003] As demand for telecommunications increases, optical fiber services are being extended in more and more areas. To more efficiently extend the fiber optic service into areas where current and future customers are located, often distribution cables with more then one optical fiber are utilized. To provide service to a particular premises in the area, the distribution cables may be received within a fiber access terminal. Such terminals provide a location in the field where one or more optical fibers of the distribution cable may be split out from the distribution cable. The remainder of the fibers within the distribution cable may then be expressed through the fiber access terminal to extend to another location where service is desired.
[0004] Within the fiber access terminal, a variety of fiber terminations and equipment is located. Typically, a base of the fiber access terminal is buried in the ground, and an upper portion of the fiber access terminal is positioned above the ground. There is a need to protect the fiber terminations and equipment within the fiber access terminal from contaminants, such as weather, water, debris, and animals.
SUMMARY
[0005] The present invention relates to a fiber access terminal including a base defining an interior and mountable to the ground. A dome cover defines an enclosed interior and is mounted to the base. A frame holds telecommunications equipment and is mounted to the base and extends into the interior defined by the dome cover. The frame and the base cooperate to define one or more passageways between an interior defined by the base and the interior defined by the dome cover. A removable cover is provided to close the one or more passageways. In such a manner, contamination of the interior of the dome cover and the telecommunications equipment contained within is lessened.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate several aspects of the present invention and together with the description, serve to explain the principles of the invention. A brief descriptions of the drawings is as follows:
[0007] FIG. 1 is a first perspective view of a fiber access terminal according to the present invention.
[0008] FIG. 2 is a further perspective view of the fiber access terminal of FIG. 1 .
[0009] FIG. 3 is a side view of the fiber access terminal of FIG. 1 , showing the base mounted in the ground and cable leading to and exiting from the base.
[0010] FIG. 4 is a perspective view like FIG. 1 , without the dome cover.
[0011] FIG. 5 is a perspective view like FIG. 2 , without the dome cover.
[0012] FIG. 6 is an exploded perspective view of FIG. 5 .
[0013] FIG. 7 is a first perspective view of the removable covers.
[0014] FIG. 8 is a second perspective view of the removable covers.
[0015] FIG. 9 is a top view of the removable covers.
[0016] FIG. 10 is first side view of the removable covers.
[0017] FIG. 11 is a second side view of the removable covers.
[0018] FIG. 12 is a first perspective view of an alternative embodiment for the frame.
[0019] FIG. 13 is an enlarged perspective view of the alternative frame of FIG. 12 with adapters.
[0020] FIG. 14 is a second perspective view of the alternative frame of FIG. 12 .
[0021] FIG. 15 shows a distribution cable and clamp, along with a strength member clamp.
[0022] FIG. 16 shows a side view of the strength member clamp.
[0023] FIG. 17 shows the strength member clamp of FIG. 16 in exploded form.
[0024] FIG. 18 shows the alternative frame of FIG. 12 mounted to the base to form a fiber access terminal, and including a tether to hold the removable covers; the removable covers shown slightly raised relative to the base.
[0025] FIG. 19 is a perspective view of the fiber access terminal including the base, removable covers, and frame of FIG. 18 , with the dome cover partially removed.
[0026] FIG. 20 is an exploded perspective view of the fiber access terminal of FIG. 18 .
[0027] FIG. 21 is a further exploded perspective view of the fiber access terminal of FIG. 18 .
[0028] FIG. 22 is a side view of the removable covers of FIG. 18 , including the tether.
[0029] FIG. 23 is a side view of a first side of the frame of FIG. 12 , showing example cabling.
[0030] FIG. 24 is a second side view of the frame of FIG. 12 , showing example cabling.
DETAILED DESCRIPTION
[0031] Reference will now be made in detail to the exemplary aspects of the present invention that are illustrated in the accompanying drawings. Whatever possible, the same reference numbers will be used through out the drawings to refer to the same or like parts. Referring now to FIGS. 1-11 , a fiber access terminal 10 is shown including a base 12 , and a dome cover 14 which define a protected interior 16 . A frame 18 is mounted to base 12 and holds telecommunication equipment 19 , such as terminations, splices, and breakouts. The frame 18 is mounted to the base and extends into an interior 20 of dome cover 14 . A first end 24 of base 12 is mounted below ground level 21 . A second end 26 of base 12 projects above ground level and mounts to a bottom end 28 of dome cover 14 . Latches 30 , 31 mount dome cover 14 to base 12 .
[0032] Frame 18 includes a first side 32 and an opposite second side 34 . One or both of sides 32 , 34 can hold the telecommunications equipment. First and second sides 32 , 34 of frame 18 cooperate with second end 26 of base 12 to define first and second passageways 42 , 44 extending between an interior 36 of base 12 and interior 20 of dome cover 14 from base 12 . First and second passageways 42 , 44 can allow for undesirable elements to enter interior 20 of dome cover 14 , such as moisture and animals. Moisture in the air can pass from the ground into dome cover 14 and condense on dome cover 14 or on frame 18 and the telecommunications equipment. Animals, such as mice, can enter interior 20 of dome cover 14 from base 12 and disrupt the cable connections. Hand access to the passageways 42 , 44 is needed during system set up to allow the cables passing through the ground to pass through into dome cover interior 20 .
[0033] Terminal 10 includes a cover system 50 for selectively covering the first and second passageways 42 , 44 . In the preferred embodiment, cover system 50 includes a first removable cover 52 for closing first passageway 42 , and a separate, second removable cover 54 for closing second passageway 44 .
[0034] First removable cover 52 includes a top member 62 and a compressible base member 64 mounted to the top member 62 . The compressible base member preferably engages the frame 18 and the base 12 to close the first passageway 42 . The compressible base member 64 is preferably made from a material such as foam. Foam base member 64 and the other polymeric materials preferably meet the anti-fungus growth tests as specified in the GR-13-Core requirements for Telcordia Requirements for Outside Plant Enclosures, specifically the ASTM G-21 test. One example foam that is usable is SCE-41 neoprene, closed cell foam.
[0035] Preferably top member 62 of first removable cover 56 is planar in shape and is made from plastic, such as ABS. Foam base member 64 can be joined to planar top member 62 with adhesive. Preferably, top member 62 has a first outer edge portion 66 which extends beyond the outer edge portion of foam base member 64 such that a rim is defined to engage the top edge of base 12 when first removable cover 52 is in position to close first passageway 42 . In addition, an inner edge region 72 of first removable cover 52 includes the foam base member 64 extending beyond an edge of planar top member 62 in areas 73 in order to better close air passageways around cables entering interior 20 of dome cover 14 .
[0036] Second removable cover 54 is constructed in a similar manner and like parts are designated with an apostrophe (′). In cover 52 , areas 73 are used to seal around the distribution cables which bring service to and from terminal 10 . In cover 54 , area 73 ′is used to seal around the drop cables which lead to customers' premises. Variations are possible in the perimeter shapes of first and second removable covers 52 , 54 in order to fit the first and second passageways 42 , 44 of differently shaped terminals. While FIGS. 7-11 show covers 52 , 54 together, covers 52 , 54 are separate units. Covers 52 , 54 can be operated separately to selectively close or open passageways 42 , 44 .
[0037] A latch 82 is provided to hold first removable cover 52 in position so that first removable cover 52 does not inadvertently dislodge from its closed position. Latch 82 includes a pivoting member 84 which selectively blocks removal of first removable cover 52 from its position closing first passageway 42 . Similar latches 82 are provided to hold second removable cover 54 in position. Latches 82 are movable to allow later access to passageways 42 , 44 .
[0038] Frame 18 includes distribution cable clamps 102 , 104 on first side 32 of frame 18 . Distribution cable clamps 102 , 104 clamp to distribution cables extending to and from terminal 10 . In use, one or more of the fiber optic cables within a distribution cable is broken out into drop cables within terminal 10 . A remainder of the cables in distribution cable are expressed through terminal 10 .
[0039] Frame 18 includes a splice holder 110 . Frame 18 can also include fiber optic adapters 114 (see FIGS. 13 and 23 ) for holding two fiber optic connectors 115 in axial alignment. One fiber optic connector connected at one of adapters 114 is spliced to one of the broken out fibers from the distribution cable entering terminal 10 . A second fiber optic connector connected to the first fiber optic connector at the selected adapter 114 is a drop cable, extending to a customer's premises. A drop cable clamp 118 on frame 18 holds the drop cable in a secure manner.
[0040] FIGS. 12-14 show an alternative frame 18 ′. Both of frames 18 , 18 ′ include various structures to manage the cables, splices and terminations in an organized manner. For example, radius limiters 170 , 172 , tie-offs 174 , and clips 176 can be used.
[0041] To further hold the distribution cables to frame 18 , a strength member clamp 122 is provided to clamp to the strength member of a distribution cable. See also FIGS. 15-17 . Clamp 122 includes a fastener mount 124 for mounting to frame 18 . Clamp 122 further includes a fastener clamp 126 for connecting to the strength member 109 . Screw 127 cooperates with housing 125 and tab 129 to securely hold the strength member 109 . Electrical grounds 128 for grounding the distribution cables can be used if desired.
[0042] Referring now to FIGS. 18-24 , an alternative terminal 10 ′ is shown with a base 12 , dome cover 14 , and removable covers 52 , 54 . To keep removable covers 52 , 54 from becoming separated from terminal 10 ′, a tether 140 is used. Tether 140 includes a first portion 142 which connects first removable cover 52 to frame 18 ′. A second portion 144 connects second removable cover 54 to frame 18 ′. In one preferred embodiment, tether 140 is a single strap or other elongated member extending through a hole 150 in frame 18 ′ with removable covers 52 , 54 connected at each end.
[0043] In one possible embodiment, tether 140 is made from an o-ring compressible material which is cut to define two ends. Each end 152 , 154 is passed through a hole 162 , 164 in each of removable covers 52 , 54 , respectively. Each end 152 , 154 is crimped with crimps 182 , 184 to prevent removable covers 52 , 54 from separating from tether 140 .
[0044] During use, tether 140 keeps removable covers 52 , 54 adjacent to frame 18 ′. Should access to an interior of base 12 be desired, dome cover 14 is removed, exposing frame 18 ′ and removable covers 52 , 54 . One or both of removable covers 52 , 54 is removed from their positions closing the passageways into base 12 . Tether 140 allows one or both of removable covers 52 , 54 to hang along side an exterior of base 12 . Tether 140 would prevent the user from reinstalling dome cover 14 onto base 12 , unless the removable covers 52 , 54 were back in the correct closed positions.
[0045] Frame 18 ′ includes protrusions 135 to help prevent cover 54 from tipping, and possibly allowing access between base 12 , and dome cover 14 after cover 54 is placed in the closed position. Protrusions 135 are located below cover 54 in use. Cover 52 is prevented from tipping by latch 30 positioned above cover 52 during use.
[0046] In the field, distribution cable 106 enters terminal 10 , 10 ′ from the ground (see FIG. 1 ). One or more of the inner cables 132 of distribution cable 106 is broken out into one or more drop cables 116 (see FIGS. 1, 23 and 24 ), which lead to the customers' premises. A remainder of the cables 132 are expressed through terminal 10 , 10 ′ at cables 133 and exit terminal 10 , 10 ′ at distribution cable 108 back into the ground (see FIGS. 1 and 24 ). Cable 108 passes to another remote terminal 10 , 10 ′, or other location where service is desired. Within terminal 10 , 10 ′, the cable or cables 132 to be broken out are connected through splices at splice holder 110 , and possibly a fiber optic adapters 114 to the drop cables 116 . Cables 117 link the splices at splice holder 110 to the fiber optic adapters 114 connected to the drop cables 116 (see FIGS. 23 and 24 ). Strength members 109 associated with distribution cables 106 , 108 are clamped with strength clamping members 122 to frame 18 , 18 ′. Ground wires 111 can be linked to frames 18 , 18 ′ with electrical grounds 128 .
[0047] The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.
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A fiber access terminal includes a drop cable side and a distribution cable side. The sides are separated by a frame to which a variety of cable management and cable connections components may be mounted. Optical fibers are routed from drop and distribution cables through a plurality of routing paths to splice trays for connection to other optical fibers. The terminal includes a base and a dome cover mounted to the base defining an enclosed interior. Passageways between the base and the dome cover are closed by removable covers to limit moisture and animals from accessing an interior of the dome cover. A tether connects the removable covers to the frame.
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INTRODUCTION
Field of the Invention
[0001] The invention relates to photoacoustic tomography (PAT), sometimes alternatively referred to as “optoacoustic tomography (OAT)” or thermoacoustic tomography (TAT)” and perhaps more correctly photoacoustic imaging (PAI). In other terms, the invention applies to any form of tomography in which a photoacoustic source is produced inside the body, caused by thermal expansion, in turn caused by absorption of externally-applied electromagnetic waves. The term “PAI” or “photoacoustic imaging” is used in this specification.
[0002] PAI is an imaging technique which measures optical absorption, which is related to the optical absorption coefficient and the optical fluence. It has clinical applications in monitoring sub-surface tissue.
[0003] Current PAI systems provide mostly qualitative data and hence the applications are limited. This arises because in PAI the optical fluence needs to be known at each volume element (voxel). The paper Jun Xia et al “Calibration-free quantification of absolute oxygen saturation based on the dynamics of photoacoustic signals” OPTICS LETTERS (Vol. 38, No. 15/Aug. 1, 2013 describes an approach to addressing the problem of determining optical fluence by taking advantage of the dynamics in oxygen saturation (sO 2 ), where for each wavelength the ratio of photoacoustic amplitudes measured at different sO 2 states is utilized.
[0004] Other documents in this field are:
WO2011/038006 (Visen) WO2011/000389 (Helmhno ltz) B. T. Cox, J. G. Laufer, P. C. Beard: “The 1-15 challenges for quantitative photoacoustic imaging” In: 27 Feb. 2009, SPIE, PO Box 10 Bellinham Wash. 98227-0010 USA, XP040492002, DOI: 10.1117/12.806788 Xu Minghua, et. Al: “Photoacoustic imaging in biomedicine”, Review of Scientific Instruments, AIP, Melville, N.Y., US, vol. 77, no. 4, 17 Apr. 2006, pages 41101-041101, XP012092965, ISSN: 0034-6748, DOI: 10.1063/1.2195024
[0009] The invention is directed towards providing an improved system and method for PAI.
SUMMARY OF THE INVENTION
[0010] This invention is aimed at making photoacoustic imaging (PAI) quantitative. Several attempts have been made to calibrate the PAI system, but this has proved elusive since the light fluence delivered to each voxel is unknown, hence the pressure amplitude detected may be indicative of a high concentration of absorber or due to a high light fluence. In order to disentangle these, the fluence at each voxel must be determined. The invention uses the knowledge that the content of the arterial blood is the same through the organism and hence it can be used as a local calibration “guide star” to calibrate the system for local fluence distribution. The absorption coefficient is known from the arterial oxygen saturation (SaO 2 ) and total haemoglobin (HbT). A calibrated system will be quantitative and hence has many applications in clinical, pre-clinical and fundamental science and discovery, including stem cell tracking, optimisation of cancer treatments and basic physiology studies.
[0011] According to the invention, there is provided a method of calibrating a PAI system, the method comprising the steps of:
determining optical fluence at voxels within arteries of a human or animal, interpolating from said measurements to provide a fluence map with a fluence value for all voxels of interest, and storing said fluence map for subsequent use in making PAI measurements, wherein the arterial optical fluence is determined on the basis that the arterial oxygen saturation (SaO 2 ) is the same throughout the arterial part of the circulation system.
[0015] In one embodiment, the fluence map is generated for all wavelengths of interest.
[0016] In one embodiment, the method includes measuring SaO 2 in order to determine said optical fluence of voxels in the patient's arteries. In one embodiment, pulse oximetry is used to determine the SaO 2 value.
[0017] In one embodiment, the arterial optical fluence is determined on the basis that the arterial total haemoglobin fraction (HbT) is the same throughout the arterial part of the circulation system.
[0018] In one embodiment, the method includes measuring SaO 2 and HbT in order to determine said optical fluence of voxels. In one embodiment, pulse co-oximetry is used to determine the HbT value.
[0019] In one embodiment, the arterial oxygen saturation (SaO 2 ) is determined according to:
[0000]
s
O
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=
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Hb
(
λ
1
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[0020] In one embodiment, the calibration uses the small path length change in arteries and/or arterioles to isolate absorption due to only arterial blood.
[0021] In one embodiment, the pulse oximetry uses the small path length change in arteries and/or arterioles to isolate absorption due to only arterial blood.
[0022] In one embodiment, the arterioles are in the finger.
[0023] In another aspect, the invention provides a PAI system comprising a processor adapted to perform calibration in a method as defined above in any embodiment.
[0024] In one embodiment, the system is adapted to perform assessment of tumour treatment potential by determining vascularity such as perfused vessel density, and borders.
[0025] In one embodiment, the system is adapted to perform assessment of tumour treatment potential by identifying the volume and borders of hypoxic regions which may not respond to cancer agents, such those designed to produce singlet oxygen as part of the treatment mechanism.
[0026] In one embodiment, the system is adapted to perform assessment of drug delivery and distribution in an animal or human by using dyes or fluorophores to label the drugs. In one embodiment, the system is adapted to perform assessment of drug delivery and distribution in an animal or human by using nanoparticles to label the drugs.
[0027] In one embodiment, the system is adapted to perform assessment of drug delivery and distribution in an animal or human by using nanoparticles to label the drugs.
[0028] In one embodiment, the system is adapted to perform assessment of drug delivery and distribution or biodistribution (distribution of cells in an animal or human) in an animal or human by using high aspect ratio or other nanoparticles to label the drugs, thereby permitting deeper imaging. In one embodiment, the system is adapted to perform assessment of biodistribution (distribution of cells in an animal or human) for stem cell therapy.
[0029] In one embodiment, the system is adapted to perform assessment of biodistribution (distribution of cells in an animal or human) for stem cell therapy using dyes/fluorophores/nanoparticles to label the cells.
[0030] In one embodiment, the system comprises an endoscope for use in said calibration
DETAILED DESCRIPTION OF THE INVENTION
[0031] The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:—
[0032] FIG. 1 shows an ultrasound probe in use;
[0033] FIG. 2 shows a system for determining arterial oxygen saturation SaO 2 ;
[0034] FIG. 3 shows a pre-clinical photoacoustic configuration; and
[0035] FIG. 4 shows a system for both pre-clinical and clinical use.
[0036] It is known that a pulse oximetry tool can be used to non-invasively determine arterial oxygen saturation (SaO 2 ), and this is the same everywhere within the arterial side of the circulation system.
[0037] A tomographic system of the invention divides the tissue into volume elements (voxels) and measures the acoustic pressure generated at each voxel within the arteries in the field of view. From this, and knowledge that the SaO 2 is the same at all of these locations, it can readily calculate the fluence at all voxels within the arteries. From this it interpolates to calculate a map of fluence at all voxels. Once it has the fluence map it is calibrated, and can give the true concentration of any absorbing chromophore in any voxel in the field of view.
[0038] The system of the invention performs the following steps:
(a) Acquire the raw photoacoustic pressure measurement at each voxel. (b) In the region of interest, find the nearest artery/arteriole. (c) Calculate the local fluence from the measurement in (b). Since the concentration of oxy and deoxy-haemoglobin is the same everywhere in the arterial system (can be easily measured on the finger) the absorption coefficient of arterial blood can be calculated with a pulse oximeter measurement. (d) Apply the local fluence as a calibration factor to give the concentration of any absorber in the voxel with known absorption coefficient within a region expected to have the same fluence (e.g. 10×10×2 mm). (e) Repeat (a) to (d) for all wavelengths of interest (as determined from the absorption spectra of the analytes (absorbers).
[0044] The system calculates a fluence map from measurements at the arteries distributed through the volume and applies that as the calibration factor. In the first instance the arteries are manually identified and the fluence for each voxel is interpolated from those identified. This could be automated using the pulsing nature of arterial blood.
[0045] For calibration, the system determines the optical fluence at voxels within arteries of a human or animal. It does this by measuring the acoustic pressure pulse amplitude. This is proportional to the energy deposited in the voxel. Energy deposited is essentially the absorption coefficient times fluence. The absorption coefficient is known from SaO 2 and HbT, and knowing these are the same everywhere in the arterial system, the system of the invention can determine a fluence map for all voxels in the arterial ‘tree’. It interpolates to estimate the fluence in the remaining voxels.
[0046] Referring to the drawings FIG. 1 shows use of a clinical ultrasound probe 1 which is operated in reflection mode. Instead of ultrasound output, the acoustic signal is generated by short (typically <10 ns) laser pulses which are absorbed in the tissue. The instrument comprises a tuneable laser system for generating light pulses of approximately 50 mJ in 10 ns at a variation of wavelengths. The light pulses are absorbed by all arteries in the illuminated field. The arterial blood will rise in temperature by a few mK and, since the pulse time is too short for thermodilution, will release an acoustic vibration (pressure wave) with a spectrum of frequencies in the MHz range. This pressure variation will travel isotropically in all directions and may be detected in any direction. We assume here that it is detected in reflection mode similar to a clinical ultrasound instrument.
[0047] The oxygen saturation (sO 2 ) is the fraction of total haemoglobin (HbT) bound to oxygen:
[0000]
s
O
2
=
Hb
O
2
Hb
O
2
+
Hb
=
Hb
O
2
HbT
[0048] The remaining fraction is haemoglobin which is not bound to oxygen. The arterial oxygen saturation (SaO 2 ) is the fraction of total haemoglobin in the arterial blood bound to oxygen. SaO 2 can be readily measured at the finger with a pulse oximeter (called SpO 2 just to indicate pulse measurement) and is the same at all locations in the arterial system. The Beer-Lambert law (or Beer's law) is the linear relationship between absorbance and concentration of an absorbing species:
[0000]
A=α
λ
×c
where A is the measured absorbance, α λ is a wavelength-dependent absorption coefficient, x is the path length, and c is the analyte concentration,
OR
[0050]
dI=−cσ
a
Idx
where dI is the measured variation in transmitted intensity, I is the incident intensity, σ a is a wavelength-dependent absorption cross-section, dx is the path length change, and c is the species concentration.
[0052] Referring to FIG. 2 , red light of wavelength 660 nm ( 201 ) and mean intensity I R falls on a detector 203 having passed through the finger 204 of a patient in critical care. Infrared light 202 of wavelength 960 nm and mean intensity I IR falls on the same detector having traveled the same path. The 660 nm light has a peak-to-peak intensity variation of dI R , while that at 960 nm varies by dI IR . The red and infrared light is pulsed on and off alternatively so that they can be detected on the same detector-amplifier combination and de-multiplexed later to provide the red and infrared component signals. The cardio-synchronous variation in blood volume leads to a varying optical path length. The Beer-Lambert law dictates that the received intensity is proportional to the varying optical path length. The Beer-Lambert law dictates that the received intensity is proportional to the absorption coefficient of the substance through which it passes, in this case blood. Each translucent substance has an absorption spectrum which is the variation in absorption with wavelength. The pulse oximeter operates by using the small path length change in the arteries of the finger caused by the cardiac pulse (only present on the arterial side) to isolate absorption due to only the arterial blood. The instrument filters the alternating signals of amplitude dI R &dI IR and normalises them by I R & I IR .
[0000]
(
dI
/
I
)
R
(
dI
/
I
)
IR
=
Sa
O
2
σ
ao
,
R
+
(
1
-
Sa
O
2
)
σ
ar
,
R
Sa
O
2
σ
ao
,
IR
+
(
1
-
Sa
O
2
)
σ
ar
,
IR
Sa
O
2
=
σ
ar
,
R
-
(
dI
/
I
)
R
(
dI
/
I
)
IR
·
σ
ar
,
IR
-
σ
ao
,
R
+
σ
ar
,
R
+
(
σ
ao
,
IR
-
σ
ar
,
IR
)
·
(
dI
/
I
)
R
(
dI
/
I
)
IR
[0053] FIG. 3 shows a pre-clinical PAI system. A laser 301 provides a pulsed irradiation source. The laser beam is redirected by a mirror 312 and focused by a lens 311 through a pinhole 310 , where it is spatially filtered, and then focused by an objective lens 313 . Ultrasonic focusing is achieved by the use of an acoustic lens 315 . The objective lens and the ultrasonic transducer are confocally configured via a correction lens 309 , a right angle prism 314 , and a silicon oil layer 307 . The sample 304 is separated from the acoustic lens by a plastic membrane 305 and a water tank 306 . Acoustic signals are generated in the sample 304 target site, due to the temperature rise associated with the absorption of pulsed laser energy, focused from the objective lens 313 . The detected acoustic data is sent from the transducer ( 308 ), via an amplifier 303 , to a data acquisition and signal processing unit 302 , where it is converted into an image using image reconstruction techniques. 3D images are generated by raster scanning in the transverse plane, which is achieved by moving the sample 304 on a scanner 305 (a two-dimensional moving platform). The scanner is controlled by a scanner controller 304 , which is controlled by the data acquisition device 302
[0054] FIG. 4 shows the use of a PAI system with clinical and pre-clinical applications. The probe shown in this system is a photoacoustic probe 409 , i.e. one in which the laser source and ultrasonic transducer detectors are housed in the same unit. Pulsed optical energy is generated by a laser 401 , and directed via mirrors 412 , 411 to an optical parametric oscillator (OPO) 402 , which is a device used to convert the incident light into a different wavelength within a given range, specified by a control unit 404 . The laser output from the OPO 402 is passed through a lens 406 , which focuses the light onto a fibre optic coupling 407 , which is connected to a fibre optic cable 413 , and then to the probe 409 . Acoustic signals are generated in the site of interest in a patient 408 , due to the absorption of pulsed laser energy delivered by the probe. The acoustic information is relayed, via an ultrasound detector 403 , to a signal processing and control unit 404 , where the data is processed into an image by a reconstruction algorithm. 3D images can be obtained by moving the probe across the surface of the tissue with a stepper motor 410 .
[0055] The signal processing and control unit 404 causes the OPO 402 to deliver light pulses at 750 nm for one scan and at 795 nm (isobestic for Hb and HbO 2 ) for another scan and 1064 nm for a third scan (other wavelengths could be used). A voltage related to sound pressure is detected by the ultrasound detector 403 and fed to the signal processing and control unit 404 where the below equations can be used to estimate blood sO 2 from two or more of these wavelengths. Since all of these wavelengths are strongly absorbed by blood, the ultrasound transducer 403 will detect strong signals from voxels containing blood and the signal processing and control unit 404 will be able to render this data as images of the arterial and venous trees within the volume imaged. Hence the arterial tree can be segmented out and can act as a distributed calibration reference for the fluence throughout the tissue. This will be used as described below to provide a fluence map and hence calibrated distribution of sO 2 or other absorber of interest.
[0056] The local fluence (F) is proportional to the initial pressure rise (p 0 ) and inversely proportional to the product of the Grüneisen coefficient (F) and the optical absorption coefficient (μ a ), thus:
[0000]
F
=
p
0
Γμ
a
[0057] Since the Grüneisen coefficient (F) is independent of wavelength it cancels in ratiometric measurements (i.e. we are generally dividing the measured p 0 at one wavelength by that at another wavelength) or we can use spectrometrically measured Γ [Proc. SPIE 8581, Photons Plus Ultrasound: Imaging and Sensing 2013, 858138 (Mar. 4, 2013); doi:10.1117/12.2004117] or can assume values for fat, skin, muscle and blood from the literature. Hence in most cases we can view p 0 as the simple product μ a F. For visible and near-infrared light, the main absorbers in a blood vessel are oxy- (HbO 2 ) and deoxy-haemoglobin (Hb). Therefore, the optical absorption coefficient at wavelength λ 1 and sO 2 can be expressed as:
[0000] μ a (λ 1 ;sO 2 )=ln(10)[ C HbT ·sO 2 ·ε HbO2 (λ 1 )+ C HbT ·(1− sO 2 )·ε Hb (λ 1 )]
[0058] where C HbT is the total hemoglobin concentration, and εHbO 2 and ε Hb are the molar extinction coefficients of HbO 2 and Hb, respectively, all of which are known a priori, or can be determined using pulse (co-)oximetry or a lab co-oximeter via arterial blood sampling. Hence the system can calculate the fluence at each voxel and produce a 3D fluence map. From this the system can determine sO 2 in other capillaries, venules and veins as well as any analyte with a significant and distinct absorption spectrum.
[0059] Where the fluence is not known and where the path lengths are well known (photoacoustic microscopy) Wang et al 2006 (Xueding Wang, Xueyi Xie, Geng Ku, Lihong V. Wang, George Stoica, 2006. “Noninvasive imaging of haemoglobin concentration and oxygenation in the rat brain using high-resolution photoacoustic tomography” Biomed Opt. 11 (2), 024015; doi:10.1117/1.2192804) give these equations for HhT and sO 2 , which attempt to minimize the impact of the unknowns:
[0000]
s
O
2
=
[
Hb
O
2
]
[
Hb
O
2
]
+
[
Hb
]
=
μ
a
λ
2
ɛ
Hb
λ
1
-
μ
a
λ
1
ɛ
Hb
λ
2
μ
a
λ
1
Δɛ
Hb
λ
2
-
μ
a
λ
2
Δɛ
Hb
λ
1
HbT
=
[
Hb
O
2
]
+
[
Hb
]
=
μ
a
λ
1
Δɛ
Hb
λ
2
-
μ
a
λ
2
Δɛ
Hb
λ
1
ɛ
Hb
λ
1
ɛ
HbO
2
λ
2
-
ɛ
Hb
λ
2
ɛ
HbO
2
λ
1
[0060] However, from the equation for μ a (λ 1 ; sO 2 ) it follows [2013/Vol. 38, No. 15/OPTICS LETTERS 2801] that the photoacoustic pressure amplitude ratio for two wavelengths, (λ 1 , λ 2 ) is thus:
[0000]
p
0
(
λ
1
,
s
O
2
)
=
CHbT
[
s
O
2
×
ɛ
Hb
O
2
(
λ
1
)
+
(
1
-
s
O
2
)
×
ɛ
Hb
(
λ
1
)
]
F
(
λ
1
)
p
0
(
λ
2
,
s
O
2
)
=
CHbT
[
s
O
2
×
ɛ
Hb
O
2
(
λ
2
)
+
(
1
-
s
O
2
)
×
ɛ
Hb
(
λ
2
)
]
F
(
λ
2
)
[0000] which can be re-arranged to give sO 2 in any vessel thus:
[0000]
SO
2
=
ɛ
Hb
(
λ
1
)
·
F
(
λ
1
)
-
ɛ
H
b
(
λ
2
)
·
F
(
λ
2
)
·
P
0
(
λ
1
,
SO
2
)
P
0
(
λ
2
,
SO
2
)
P
0
(
λ
1
,
SO
2
)
P
0
(
λ
2
,
SO
2
)
·
F
(
λ
2
)
(
C
HbT
·
ɛ
HbO
2
(
λ
2
)
-
ɛ
Hb
(
λ
2
)
)
+
F
(
λ
1
)
(
ɛ
Hb
(
λ
1
)
-
C
HbT
·
ɛ
HbO
2
(
λ
1
)
)
[0061] Once the fluence is determined as set out above, the system can be calibrated and many applications become possible for clinical, pre-clinical (and other studies). These include the assessment of biodistribution (distribution of cells or drugs in an animal or human) for stem cell therapy and the identification of hypoxic regions in tumours.
[0062] Stem cell therapies have the potential to generate/re-generate tissues or whole organs. Cells may be taken from the same patient to avoid biocompatibility, rejection issues. Progress is limited due to lack of methods to determine the biodistribution within an animal or human. Currently, this mainly relies on euthanizing the animal and histological examination. This provides one time point and, since this is a dynamic process, it is unclear where this time point is within that process (peak, before peak after peak . . . ). In vivo monitoring of stem cell distribution in living animals and humans would permit longitudinal studies showing the time course and facilitate optimised treatment regimens. Furthermore, stem cells are proposed as a mechanism of drug delivery since they will in some circumstances have the ability to locate tumours. PAI imaging for stem cell tracking will likely require cell labelling with nanoparticles or dyes or fluorophores.
[0063] Drug resistance is a major problem with cancer treatments. Many cancer agents try to generate singlet oxygen within the tumour and the singlet oxygen kills the tumour cells. A substantial proportion of resistant tumours are found to have hypoxic regions (lack oxygen) and hence have low potential to produce singlet oxygen. This may be because the tumour has grown rapidly (uncontrollably) and many cells are too far from the blood vessels for oxygen delivery. Imaging of the vasculature and its sO 2 content will facilitate the identification of tumours which will be resistant to these treatments and hence save these patients the trauma of those chemotherapy sessions.
[0064] A calibrated system will also tremendously aid fundamental science and discovery, by providing calibrated reliable data relating to many things including oxygen supply and consumption. For example, it could provide much more direct quantitative imaging of brain function and better knowledge of the parts of the brain involved in various functions and importantly the relative contribution (or load) from various parts of the brain.
[0065] The invention is not limited to the embodiments described but may be varied in construction and detail. For example the processing for calibration or for any of the analysis techniques may be performed by a remote processor linked to the photoacoustic detector, rather than the local signal processor.
|
A method of calibrating a PAI system ( 401 - 413 ) is described. The method includes a signal processing unit ( 404 ) determining optical fluence at voxels within arteries of a human or animal, and interpolating from these measurements to provide a fluence map with a fluence value for all voxels of interest. The system ( 404 ) stores the fluence map for subsequent use in making PAI measurements. The arterial optical fluence may be determined on the basis that the arterial oxygen saturation (SaO 2 ) is the same throughout the arterial part of the circulation system.
| 0
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a force structure for a printing head of a printer such as a manually operable (sweeping type) handy printer.
2. Description of the Related Art
In general, a head transfer mode printer employing a line type thermal head has been equipped with a personal wordprocessor or a compact printer. In case that the thermal head having a width of, for instance, 40 millimeters is employed in such a compact handy printer, head force of several kilograms is required so as to transfer a heat transfer ink onto a recording surface of paper to be printed. Under these conditions, in a printer of, e.g., a personal wordprocessor where a thermal head is automatically pressed against a recording paper wound on a platen in order to perform a printing operation, a predetermined printing force can be set to the printing head.
However, there is such a problem in a manually sweeping type printer that the printer body must be pressed against the recording plane. This is the reason why the force is required for the printing operation. That is, generally speaking, a typical weight of the manually sweeping type printer is about 1 kg, which is lower than the printing force to be applied by the thermal head to the ink ribbon while heat-transferring the ink layer to the recording paper. As a consequence, the operation for continuously pressing the printer body against the recording paper at force higher than a predetermined value while moving the printer body, will cause a printer operator pain. When the lower force is given to the printer body, a poor printing quality is achieved. Even if too much force is applied to the printer body, various other problems may be caused.
As one problem, there is a higher risk that the printing apparatus is inclined with respect to the moving direction. Also as another problem, a fluctuation in the printer force to the recording paper may be produced, so that the driving operation of the ink ribbon interposed between the thermal head and recording paper is disturbed. In the normal trouble case, the ink ribbon is jammed on the thermal head, interrupting the printing operation. Furthermore, the need to apply the higher force against the recording paper causes the excess mechanical strength of the printing apparatus, and therefore the higher cost.
SUMMARY OF THE INVENTION
The present invention has been made in an attempt to solve the above-described problems of the conventional printing apparatus, and therefore has an object to provide a printing apparatus capable of obtaining a force required for the printing operation, with applying little force if any at all to the recording paper.
In a printing apparatus according to the invention, there are provided:
a printing apparatus comprising:
a thermal head having a large number of heating resistor elements arranged at predetermined pitches thereof;
an actuator being deformable in itself in such a manner as performing the movements of expansion and contraction in synchronism with an alternating voltage supplied thereto;
supporting means for supporting said actuator; and
coupling means for coupling said thermal head with said actuator in such a manner that said movements of said actuator can be delivered to said thermal head;
whereby said thermal head generates vibrations, in response to said movements of said actuator, which causes a printing force against a recording paper.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, reference is made to the following description in conjunction with the accompanying drawings, in which:
FIG. 1 is a perspective view of a major construction of the printing apparatus according to the invention;
FIG. 2 is a perspective view of an overall printing apparatus shown in FIG. 1;
FIG. 3 is a block diagram of an electronic circuit of the printing apparatus shown in FIG. 2;
FIG. 4 is a front view of the printing apparatus, for explaining the printing operation thereof;
FIG. 5A illustrates a characteristic graph between a time and a voltage applied to a piezoelectric actuator; and,
FIG. 5B illustrates a characteristic graph between a time and a force produced by the vibration of the thermal head, applied to the recording paper.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
OVERALL PRINTING APPARATUS
FIG. 2 is a perspective view of an overall printing apparatus 1 according to a preferred embodiment of the invention. Reference numeral 10 denotes a case. This case 10 is formed in such a size that it can be sufficiently handled by a user's hand. A mode changing switch 11 is provided on a left side of the printing apparatus 1. The function of this mode changing switch 11 is to both turn on/off a power supply, and change a wordprocessor mode, i.e., document forming mode "WP" and a printing mode "PR". When either wordprocessor mode "WP" or printing mode "PR" is designated, the power supply is turned on. A key input unit 12 and a display unit 13 are formed on a front side of the printing apparatus 1. In the key input unit 12, there are provided a character/symbol input key 14, a function key 15, a cursor key 16 and a print key 20. As the display unit 13, for instance, a dot-display type liquid crystal display device is employed. A printing head mechanism "HA" is mounted on a lower surface of the printing apparatus 1. This printing head mechanism "HA" includes a line type thermal head constructed of, for example, 48 dots per one line. The thermal head 27 has a large number of heating resistor elements 27a which are arranged on the lower surface thereof at a predetermined interval.
The character/symbol input key 14 is used to enter alphanumeric characters and symbols. The function key 15 includes an execution key 15a for sectioning, for instance, the commencement and end of the document entry, or the designated removing range on the document entry; and various keys such as an insertion key, delete key, and shift key. Then, the characters and symbols entered by the character/symbol input key 14 and function key 15 are successively displayed on the above-described display unit 13. A cursor key 16 functions to move a cursor "K" in the horizontal direction on the display screen on which the document and symbol are also displayed. A designation of the input position and/or of the function range is made by moving this cursor "K".
The mode changing switch 1 is used to change the wordprocessor mode "WP" for forming the document into the print mode "PR" for printing out the formed document, and vice versa. In case of printing out the document formed by the key entry, after the print mode "PR" is designated by operating the mode changing switch 11, the forming surface of the heating resistor element 27a of the thermal head 27 is brought in contact with the surface of the recording paper "A", and the printing apparatus 1 is moved in a direction indicated by an arrow "X" while depressing the print key 20. As a result, the formed document is printed out. In this case, if a user would mistakenly move this printing apparatus 1 in a direction opposite to the normal printing direction "X", a moving block mechanism employed within the printing apparatus 1 is actuated so as to prevent the erroneous printing operation.
CONSTRUCTION OF PRINTING UNIT
FIG. 1 illustrates a construction of a printing unit 21 arranged within the case 10 shown in FIG. 2. In FIG. 1, reference numeral 22 indicates an ink ribbon cassette. This ink ribbon cassette 22 has such a shape detachably mounted within the case 10 where the above-described printing unit 21 is located in a center thereof. Two ribbon spools 23a and 23b are mounted on the ink ribbon cassette 22, each of which functions as a feeding spool and a take-up spool for a heat transfer ink ribbon 24. The heat transfer ink ribbon 24 is stored within the ink ribbon cassette 22 in such a manner than one portion of the heat transfer ink ribbon 22 is exposed from a notch 25 for a printer head, which is formed in the lower end portion of the ink ribbon cassette 22.
A printing head mechanism "HA" is constructed by a thermal head 27, a piezoelectric actuator 28a, and a head mounting member 28. A cutout 26 for mounting a printer head is formed in the case 10. In a central portion of this cutout 26, the thermal head 27 is positioned in such a manner that the surface side having 20 the heating resistor elements 27a are slightly projected from the lower surface of the case 10. The thermal head 27 is coupled by bonding of adhesive, to the piezoelectric actuator 28a, which is also bonded to the head mounting member 28. As will be discussed hereinafter, this piezoelectric actuator 28a is deformable in itself in response to a supply of alternating voltage. As a result, the thermal head 27 is vibrated in synchronism with deformation of the piezoelectric actuator 28a. It should be noted that the above-described piezoelectric actuator 28a is manufactured as follows. A powder of a piezoelectric ceramic is dispersed into an organic binder to form a green sheet having a thickness of several tens micrometers, and then a metaline paste is printed on the green sheet, and finally, several hundreds of the printed green sheets are stacked to obtain the resultant piezoelectric actuator. By applying an alternating voltage, the resultant green sheets, i.e., a piezoelectric actuator 28a, are deformable in such a manner as performing the movements of expansion and contraction in a stacking direction, in other word, an axial direction thereof. An amount of deformation of the resultant green sheet is about 0.1 to 0.5% of a thickness of the stacking direction.
At the lower side of the case 10, a large opening 29 and a small opening 30 are respectively formed on each side of the cutout 26. Rubber rollers 31 and 32 are mounted on the respective openings 29 and 30. When the printing apparatus 1 is moved in the direction indicated by the arrow "X" during the printing operation, these rubber rollers 31 and 32 rotate in contact with the above-described recording paper "A". A drive gear 33 is coaxially fixed on the side portion of this rubber roller 31. A diameter of this drive gear 33 is smaller than that of the rubber roller 31. This drive gear 33 is meshed with a take-up gear 36 via intermediate gears 34, 35a and 35b. A ribbon take-up shaft 37 is integrally formed with this take-up gear 36. An arm 38 is pivotally journaled to a base portion of this take-up shaft 37 in such a way that this arm 38 is rotated around a center of this take-up shaft 37. A small gear 39 is mounted at one end of the arm 38. The small gear 39 is meshed with the take-up gear 36, whereby this gear 39 is rotated in the same rotation direction as the above-described gear 36. An arm stopper 40 is mounted in the rotation direction of the arm 38 corresponding to the take-up rotating direction of the take-up shaft 36. That is, when the take-up gear 36 is rotated in the ribbon take-up direction (i.e., a counter-clockwise direction), the arm 38 is rotated to the arm stopper 40 and thus stopped at this position. To the contrary, when the take-up shaft 36 is rotated in the reverse rotation direction (i.e., a clockwise direction), a stopper gear 39 formed on a tip portion of the arm 38 is rotated until it will be meshed with the intermediate gear 35 b, and then stopped at this position. In other words, a reverse rotation blocking mechanism is constructed in co-operation with above-described gears 35b, 36.
On the other hand, an encoder disk 41 is coupled to the intermediate gear 35a. The rotation torque of the rubber roller 31 is transmitted to the ribbon takeup shaft 37 and encoder disk 41. A plurality of slits 41a, 41b, . . . , are formed at a predetermined interval in a radial form on the encoder disk 41. Light emitting diodes (LED) 42a and 42b, and photosensors 43a and 43b are arranged at two positions opposite to each other between the successive slit formed portions on the encoder disk 41. In this case, light projected from LEDs 42a and 42b are incident upon the photosensors 43a and 43b via the slits 41a and 41b. With the above-described arrangements, when the encoder disk 41 is rotated in the normal direction by moving the printing apparatus 1 in the X-direction, the light projected from the corresponding LEDs 42a and 42b are incident upon the photosensors 43a and 43b in this order. Conversely, when the encoder disk 41 is rotated in the direction opposite to the normal direction, the photosensors 43b and 43a receive the light projected from LEDs 42a and 42b in this order. That is, an encoder 44 is constructed of an encoder disk 41, LEDs 42a, 42b, and photosensors 43a, 43b. The ink ribbon cassette 22 is detachably fitted to this printing unit 21 in such a manner that the ribbon take-up shaft 37 comes into a supporting axis. The heat transfer ink ribbon 24 which is partially projected from the lower end portion of the ribbon cassette 22, is in contact with the cutout 26 for mounting the head in the case 10. A rear lid 10a is hinged on the case 10 by a hinge 10b pivotally thereby, whereby an easy replacement of the ink ribbon cassette 22 and an easy maintenance of this printing unit can be achieved. A printed circuit board 45 is inserted between the printing unit 21 and case 10, and connected to the keys and switch groups shown in FIG. 2, and the encoder 44 and thermal head 27 employed in the printing unit 21 shown in FIG. 2.
CIRCUIT ARRANGEMENT
FIG. 3 shows a circuit arrangement of an electronic circuit formed on the printed circuit board 45.
A control unit 51 is employed to receive the mode changing signal derived from the mode changing switch 11, various key input signal from the key input unit 12, and pulse signals, i.e., a signal for detecting a drive amount of the printing apparatus 10 derived from the encoder 44. In response to the various key operation signals derived from the mode changing switch 11 and key input unit 12, the control unit 51 controls an input data memory unit 52, a display data RAM 53, a document data memory unit 56, and a thermal head drive circuit 57. The input data memory unit 52 successively stores character data such as the alphanumeric characters and symbols entered by operating the character/symbol input key 14 and function key 15 from the key input unit 12. The character/symbol data input into this input data memory unit 52 are displayed on a display unit 13 via a display character generator 58 and a display data RAM 53. A word memory unit 54 is constructed of ROM (read only memory), where a correct spelling corresponding to each word has been stored. A word coincident unit 55 makes an identification between the word stored in the input data memory unit 52, and another word stored into the word memory unit 54. After the word is input-operated, and then the execution key 15a is depressed, the word which has been stored into the input data memory unit 52 is sent to the word coincident unit 55. At the same time, the words stored into the word memory unit 54 are sequentially read out to the word coincident unit 55 under the control of the address of the control unit 51. When a retrieval operation is made in that the word which has been input from the word memory unit 54 and stored in the input data memory unit 52 is coincident with the word, a coincident signal is transferred from the word coincident unit 55 to the control unit 51. This coincident signal has a function to store the word held in the input data memory unit 52 into a predetermined address of the document data memory unit 56. Thereafter, the word held in this input data memory unit 52 is erased. To the contrary, if there is no word having the same spelling as that of the word held in the input data memory unit 52, a miss-spelling display is effected by the control unit 51. Simultaneously, this control unit 51 controls this word to be waited for the registration to the document data memory unit 56. However, as such an operation is no relevant to the present invention, no further description is made in the specification.
The respective character and symbol data of the document data which have been stored in the document data memory unit 56 are output via the display character generator 58 and the display data RAM 53 to the display unit 13, and then displayed thereon. Also, these character/symbol data are output as the actual characters via the printing character generator 58 to the thermal head drive circuit 57. In this thermal head drive circuit 57, the encoder pulses from the encoder 44 are input when the print mode signal is output from the control unit 51. In synchronism with this encoder pulse, the character data which are input via the printing character generator 59 into the thermal head drive circuit 57, are transferred to the thermal head 27 every 1 line. In this case, since the printing quality obtained by the thermal head 27 is, for instance, 24×24 dots (in a full angle), the above-described 1 line is defined by 1/24 line of 1 character.
In the above-described encoder 44, when the encoder pulses from the encoder disk 41 are received by the photosensors 43a and 43b in this order while the encoder disk 41 is rotated in the normal direction. To the contrary, when the encoder pulses are received by the photosensors 43b and 43a in this order while the encoder disk 41 is rotated in the reverse direction, no encoder pulse is output. That is to say, if the encoder disk 41 is reversely rotated, the thermal head 27 is not driven even when the printing mode "PR" is set.
To the control unit 51, a power supply voltage is applied from a power supply unit 60. An output voltage derived from this power supply unit 60 is applied via a boosting circuit 61 and an actuator drive circuit 62 to a piezoelectric actuator 28a for generating a printing force for the thermal head 27.
PRINTING OPERATION
First, when a desired document is formed, the wordprocessor mode "WP" is designated by operating the mode changing switch 11. Then, the control unit 51 is set to the wordprocessor mode "WP". Under this condition, a user operates the key input unit 12 of the printing apparatus 10 so as to sequentially enter desired characters, symbols and so on.
At the beginning, when the desired document information is key-input by manipulating the character/symbol input key 14 and function key 15, thus the entered input document data are sequentially transferred via the control unit 51 into the input data memory unit 52 which is addressed. Simultaneously, the input document data are supplied via the display character generator 58 and display data RAM 53 to the display unit 13 and displayed thereon. Then, the execution key 15a is operated after the desired document is entered, the word which has been stored in the input data memory unit 52 under the above-described controlling operation, is stored into the document data memory 56. When mistakenly entering a word, the cursor key 16 is moved to the word to be corrected, and stopped under this word. Thereafter, a predetermined correction operation such as a correction, addition, and deletion is performed.
A description will now be made on the print out operation of the document data which has been key-input according to the above-described operation. When the document data is printed out, the mode changing switch 11 is selected to the printing mode "PR" position. By operating this mode changing switch 11, the control unit 51 is set to the print mode, whereby the document data memory unit 56 is brought into the readout condition, and the thermal head drive circuit 57 is to wait the input of the encoder pulses from the encoder 44. Under these conditions, as shown in FIG. 1, a user moves the printing apparatus 1 in the direction indicated by the arrow "X" while depressing the print key 20 and the surface of the heating resistor element 27a of the thermal head 27 is in contact with the recording paper "A". While the printing apparatus 1 is moved, the rubber rollers 31 and 32 are rotated, and these rotation torques are transferred to the intermediate gears 34, 35a and 35b as illustrated in FIG. 2. Then, the encoder disk 41 is rotated in accordance with the rotations of this intermediate gear 35a. As a result, while the encoder disk 41 is rotated, the light emitted from the respective LEDs 42a and 42b is transferred and interrupted via the slits 41a and 41b to the corresponding photosensors 43a and 43b. In this case, when the printing apparatus 1 is moved in the X-direction, the encoder disk 41 is rotated in the normal condition, so that the pulse signal output from the photosensor 43a is an output from the encoder 41. This output signal is sent as a signal for detecting a travel amount of the printing apparatus 1 to the control unit 51 and thermal head drive circuit 57. The rotation torque of the rubber roller 31 is transferred to the take-up gear 36 and ribbon take-up shaft 36. Furthermore, this rotation torque is transferred to the take-up spool 23b in the ink ribbon cassette 22. As a result, the ribbon take-up spool 23b is rotated thereby to take up the heat transfer ink ribbon 24 which is guided from the ribbon supply spool 23a via the cutout 26 for mounting the head. In this case, the ribbon take-up shaft 37 is rotated, while the printing apparatus 1 is moved, in such a condition that this rotation is in accordance with a travel amount of the printing apparatus not to produce a slip between the recording paper "A" and the ink ribbon 24. Under this condition, the alternating voltage is applied to the piezoelectric actuator 28a. Thus, the piezoelectric actuator 28a is deformed in the axial direction (in the vertical direction as viewed in FIG. 4). Since the piezoelectric actuator 28a is deformed in the axial direction, it follows that the thermal head 27 is vibrated in the axial direction. When the thermal head 27 is displaced in a Y-direction shown in FIG. 4, the ink ribbon 24 is brought in contact with the recording paper "A" at a predetermined pressure load by an action of the thermal head 27.
CHARACTERISTICS OF PIEZOELECTRIC ACTUATOR
FIG. 5A illustrates a characteristic diagram on the time lapse of the alternating voltage which is applied to the piezoelectric actuator 28a. FIG. 5B represents another characteristic diagram on the time lapse of the depression force by the thermal head 27 against the recording paper "A" caused by the deformation of the piezoelectric actuator 28a. The time dimensions in the horizontal direction shown in FIGS. 5A and 5B are identical to each other. It should be noted that according to the construction of the present invention, if the transfer loss is negligible, the force "F" against the recording paper "A" by the thermal head 27 is identical to the force by the piezoelectric actuator 28a. In principle, it is easily understood to describe the force as a stretching force generating in the piezoelectric actuator 28a. As a consequence, as to the force "F" in FIG. 5B, the stretching force generating in the piezoelectric actuator 28a will be considered.
Referring now to FIGS. 5A and 5B, the stretching force "F" generating in the piezoelectric actuator 28a reaches its maximum value "F max" at a point where the voltage "E" applied to the actuator 28 increases from "0". Then, the stretching force "F" becomes "0" at another point just before the apply voltage "E" becomes maximum. During the negative time period of the voltage "E" applied to the piezoelectric actuator 28a, the actuator 28a contracts. As a result, the stretching force "F" during the negative time period becomes "0". As is apparent from FIG. 5B, an average value "F " of the stretching force "F" generating in the piezoelectric actuator 28a, is considerably low, as compared with the maximum value "F MAX " of the stretching force "F". By utilizing such a characteristic of the piezoelectric actuator 28a, a novel mechanism can be achieved which can satisfy the following trade-off conditions. That is, the printing force is smaller than the weight of the printing apparatus 1, and also the sufficient force capable of heat-transferring the ink layer of the ink ribbon to the recording paper "A".
That is to say, the average value "F " of the stretching force "F" exerted by the piezoelectric actuator 28a is set to be lower than the self weight of the printing apparatus 1, and the maximum value "F MAX " of the stretching force "F" is set to be higher than the load required for thermally transferring the ink to the recording paper "A". It is, for example, assumed that the weight of the printing apparatus 1 itself is set to be 1 kg and the optimal printing force is selected to be 3 kg or more under which the ink layer melted by the heating resistor element 27a of the thermal head 27 is thermally transferred to the recording paper "A". In this case, if the average value "F " of the stretching force is higher than 1 kg and the maximum value "F MAX " of the stretching force is equal to, or higher than 3 kg, the printing apparatus 1 is not shortage of the weight, but the sufficient printing pressure can be obtained. In other words, even if the self weight of the printing apparatus 1 is equal to 1 kg, the printing operation can be executed under the condition that no external depression force is loaded to the printing apparatus 1 against the recording paper "A". Namely, the printing operation can be performed completely under the condition only that the printing apparatus 1 is slid over the recording paper "A" with putting the printing apparatus 1 on the recording paper "A". This implies that not only the very easily printing operation can be achieved, but also the mechanical strengths of the various constructions of the printing apparatus are designed to be small since the depression force to be loaded outside the apparatus is practically lowered. Then, similarly, this enables the size of the printing apparatus 1 to be small, and the weight thereof to be light.
Referring back to FIG. 5B, it is apparent that the time period of the alternating voltage to be applied to the piezoelectric actuator 28a is needed to have faster than the generating period of the encoder pulse. Since the generating period of the encoder pulse is limited by the printing pulse width applied to the heating resistor element 27a, the time period of the alternating voltage applied to piezoelectric actuator 28a must correspond therewith. Taking account of the very recent development on the thermal print, the frequencies of the alternating voltage applicable to the piezoelectric actuator 28a are selected to be, for instance, several killo-Hertzs to several tens killo-Hertzs.
A description will now be made to the timing relationship between the printing force and the pulse applied to the heating resistor element 27a. That is, a more or less time period is required for melting the ink layer under the preparation operation that first, the heating resistor element 27a is heated by applying the pulse to this element 27a; secondly, the heat energy emitted from the heating resistor element 27a; and, finally, the transferred heat energy is stored in the ink layer (not shown in detail) formed over the ink ribbon 24. As a consequence, in FIG. 5B, it is preferable to delay the timing when the piezoelectric actuator 28a generates the maximum value "F MAX " of the stretching force "F", as compared with the starting timing when the printing pulse is supplied to the heating resistor elements 27a formed on the thermal head 27.
Thus, the above-described travel amount detecting signal which is derived as the encoder pulse from the photosensor 43a, is transferred as the output signal of the encoder 44 to the control unit 51 and thermal head drive circuit 57. As a result, the control unit 51 sequentially addressing the memory address of the document data memory unit 56 in response to the travel amount detecting signal sent from the encoder 44, whereby the document data stored therein is read out. Then, the readout document data is output via the printing character generator 59, as the individual character data, to the thermal head drive circuit 57. The thermal head drive circuit 57 drives the thermal head 27 in synchronism with the travel amount detecting signal derived from the encoder 44, namely the readout timing of the document data by the control unit 51. The document data is thermally transferred via the ink ribbon 24 to the recording paper "A" while driving the thermal head 27. In this case, while the printing apparatus is traveled, an unused portion of the ink ribbon 24 supplied from the supplying spool 23a of the ink ribbon cassette 22 is fed out, and a used portion of the ink ribbon which has been thermally transferred by the thermal head 27, is successively taken up by the take-up spool 23b. As described above, while the printing apparatus 1 is moved along the X-direction, the formed document data which have been stored in the document data memory unit 56 are sequentially printed out on the recording paper "A".
MODIFICATIONS
As apparent from the foregoing descriptions, the present invention is not limited to the above-described preferred embodiments, but may be modified without departing from the technical scope of the invention.
In the above-described preferred embodiments, the displacement of the piezoelectric actuator was directly transferred to the thermal head. If, for instance, an amount of displacement of the thermal head becomes shortage, the thermal head may be displaced by employing an enlarging mechanism for enlarging such an amount of displacement of the piezoelectric actuator. Also the ink ribbon was interposed between the thermal head 27 and recording paper "A" in the preferred embodiment. Alternatively, the inventive idea of the present invention may be applied to the following case. That is, a heat sensitive ink layer is formed on the recording paper "A", and the thermal head 27 is directly in contact with this heat sensitive ink layer. The printing apparatus according to the invention may employ a specific heat transfer system. In the specific heat transfer system, a printing head is constructed of an electrode pin and a return-path electrode, instead of the above-described heating resistor element. The heating resistor elements are formed over an entire surface of the recording paper. A power voltage is applied to the electrode pin, so that a current flows through the return-path electrode via the heating resistor elements provided on the recording paper. The heating resistor elements are heated by this current flowing therethrough.
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In a manually sweeping type printing apparatus having a lighter weight than a force in printing, the printing operation is effected without applying any external depression load. The printing apparatus includes a thermal head a piezoelectric actuator which performs movements of expansion and contraction in synchronism with an alternating voltage, and means for coupling the thermal head to the piezoelectric actuator with maintaining vibrations. The piezoelectric acutator is manufactured by stacking a plurality of piezoelectric ceramic sheets, and stretched in an axial direction thereof upon receiving the alternating voltage. This deformation causes another vibration of the thermal head in the axial direction, whereby the force against the recording paper is obtained by the vibration of the thermal head. An average value "F" of the force "F" exerted by the thermal head against the recording paper is set not to be more than the weight of the printing apparatus. Also a maximum value of the force is selected to be more than a minimum value of the required force. As a consequence, although the weight of the printing apparatus is less than the force in printing, such a printing apparatus can be realized that more than the force required for thermally-transferring the heat transfer ink to the recording paper can be delivered.
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RELATED APPLICATIONS
[0001] IBM Docket No. SJO9-002-0056US1, John A. Hulsey inventor, entitled METHOD, SYSTEM, AND APPARATUS FOR RELEASING STORAGE IN A FAST REPLICATION ENVIRONMENT filed on Apr. 8, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. The Field of the Invention
[0003] The invention relates to methods, apparatus, and systems for archiving data. Specifically, the invention relates to methods, apparatus, and systems for conducting incremental backups of data within a storage subsystem, independent of a host or file system.
[0004] 2. The Relevant Art
[0005] Data processing systems are often required to copy large amounts of data to secondary storage or to another primary data store. Historically, copying entire volumes of data required that a system suspend all tasks that might access a source and/or a target volume. Suspension of the various tasks or processes to conduct the copy operation greatly reduced the performance of such systems.
[0006] Incremental backup techniques have been developed to lessen stoppage time and to increase system performance when archiving data. Incremental backup methods are typically conducted by software residing on the host, which monitors or detects storage volume changes at a file level. For example, an incremental backup process running on the host system may be required to scan all of the files within the file system in order to ascertain which blocks of data on the storage subsystem have changed since the last backup. To perform an incremental backup, any files that have been modified since the last backup are copied to a backup device such as a tape drive during a snapshot session.
[0007] Another method to reduce stoppage time while copying data from one volume to another is referred to as an instant copy, or “flashcopy.” An instant copy or flashcopy replicates data in a manner that appears instantaneous and allows a host to continue accessing a volume while actual data transfers are deferred to a later time. Flashcopy techniques typically defer the transfer of a data block to the secondary volume until a write operation is requested to that particular block on the primary volume. Until the actual data transfer occurs, read operations to the secondary volume are redirected to the primary volume. Flashcopy techniques greatly increase the performance of data processing systems and are conducted by the storage subsystem in a manner that is transparent to the host or file system.
[0008] In addition to increased performance, flashcopy capable systems simplify the code complexity of I/O intensive processes such as those conducted on large mainframe systems and the like. While extremely useful, conducting flashcopy operations directly to a backup device is not desirable in that the actual data is not immediately transferred to the backup device, thus leaving the system more vulnerable to various failures.
[0009] Despite the progress in backup systems, a need exists for a method of performing an incremental backup without requiring knowledge of files and access to the file system. Such a method would relieve the burden on the host computer of tracking and bookkeeping tasks and would facilitate efficient use of the backup resources while enabling access to the data involved in backup operations. In particular, what is needed is a method to leverage the capabilities of flashcopy techniques when performing incremental backups of data residing on storage subsystems.
BRIEF SUMMARY OF THE INVENTION
[0010] The methods of the present invention have been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available incremental backup methods. Accordingly, the present invention provides an improved method, apparatus, and system for conducting incremental backups of data stores.
[0011] In one aspect of the invention, a method for conducting block-level incremental backups in a host-independent manner within a storage subsystem includes tracking block-level operations within the storage subsystem, and receiving an instantaneous replication (hereinafter referred to as “snapshot”) command at a first time instance. A second snapshot command is received at a second time instance, whereupon data corresponding to blocks overwritten between the first and second time instance are transferred or copied to a backup device or system.
[0012] In one embodiment, tracking block-level operations is conducted by one or more storage controllers associated with a storage subsystem in a manner which frees the host from housekeeping tasks. To facilitate conducting incremental backups, metadata describing the block-level operations is stored in a buffer and referenced to ascertain which data blocks should be transferred to the backup device or subsystem.
[0013] With the initial snapshot command in a series of snapshot commands, a full backup is conducted and the entire volume is copied to the backup device. With each subsequent snapshot command, an incremental backup is conducted by copying those blocks that were overwritten since the previous snapshot command.
[0014] With the present invention, backup operations may be initiated from a host by sending a snapshot command to the storage subsystem. Alternately, backup operations may be initiated by a timer or other process running within the storage subsystem completely independent of the host.
[0015] In another aspect of the present invention, a storage controller for controlling storage devices and conducting block-level incremental backups is configured to execute the aforementioned methods. In one embodiment, the storage controller maintains internal information referred to as metadata, which describes which data blocks have moved from the primary volume to the secondary volume in response to data writes on the primary volume and also describes where the data resides on the secondary volume. In response to a snapshot command (other than the initial snapshot command), the storage controller initiates a transfer or copy operation of those blocks which have been written on the primary volume between the previous snapshot instance and the current snapshot instance.
[0016] In another aspect of the present invention, a system for archiving data in a host-independent manner includes at least one host configured to process data and request storage services, a plurality of storage devices, and at least one controller configured to execute the aforementioned methods.
[0017] In another aspect of the present invention, a storage area network for storing data includes a plurality of storage subsystems and a network configured to interconnect the plurality of storage subsystems. At least one storage subsystem of the plurality of storage subsystems includes at least one controller configured to execute the aforementioned methods.
[0018] The various aspects of the present invention increase the performance of conducting backup operations within data processing systems. The processing burden on the host is minimized, while accessibility to the data involved with backup operations is maintained. These and other objects, features, and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order that the manner in which the advantages and objects of the invention are obtained will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
[0020] [0020]FIG. 1 is a schematic block diagram illustrating one embodiment of a network system representative of the environment wherein the present invention may be deployed;
[0021] [0021]FIG. 2 a is a schematic block diagram further illustrating a representative storage sub-system in accordance with the present invention;
[0022] [0022]FIG. 2 b is a block diagram illustrating selected modules of one embodiment of a backup capable controller of the present invention;
[0023] [0023]FIG. 3 is a flow chart illustrating one embodiment of a host-independent incremental backup method of the present invention; and
[0024] [0024]FIG. 4 is a block diagram illustrating representative results of the method of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Many of the functional units described in this specification have been labeled as modules, in order to more particularly emphasize their implementation independence. For example, modules may be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module. For example, a module of executable code could be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices.
[0026] Modules may also be implemented in hardware as electronic circuits comprising custom VLSI circuitry, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.
[0027] Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.
[0028] Referring to FIG. 1, a network system 100 is representative of the environment wherein the present invention may be deployed. The depicted network system 100 includes workstations 110 and servers 120 interconnected via a network 130 . The network 100 may comprise a local area network and/or a wide area network.
[0029] The depicted network system 100 also includes one or more storage subsystems 140 interconnected with the servers 120 via a storage network 150 . In one embodiment, the servers 120 are mainframe computers configured to conduct high bandwidth I/O operations with the storage subsystems 140 . The storage subsystems 140 are in one embodiment fault tolerant subsystems containing redundant storage controllers 160 and storage devices 170 .
[0030] [0030]FIG. 2 a is a schematic block diagram of a storage sub-system 200 further illustrating an environment in which the present invention may be deployed. The storage sub-system 200 is a representative example of sub-systems in which the present invention may be deployed and is one example of the configuration of the storage subsystem 140 depicted in FIG. 1. The storage sub-system 200 includes a storage array 210 and one or more controllers 220 . The storage sub-system 200 preferably includes a plurality of controllers 220 in order to achieve increased reliability through redundancy. The storage array 210 is also preferably made redundant by including a number of storage devices 230 interconnected with an array loop 240 .
[0031] In the depicted embodiment, the storage devices 230 are interconnected with an array loop 240 . The array loop 240 also interconnects the controllers 220 with the storage array 210 . The array loop 240 circulates communications in both directions to increase reliability and throughput. In one embodiment, the array loops 240 are point-to-point loops such as those defined by the fibre channel standard.
[0032] In the depicted embodiment, the controllers 220 each support a host connection 250 . The controllers 220 receive access requests via the host connection 250 and service those requests by transferring blocks of data to and from the storage array 210 . The blocks of data that are transferred to the storage array 210 may be redundantly encoded to permit error detection and data recovery in the event of failure of one of the storage devices 230 . Typically, the controllers 220 organize the storage devices 230 in a redundant manner and provide access to one or more volumes to a host.
[0033] In addition to connection and data redundancy, the controllers 220 in one embodiment support some type of an instantaneous replication or “flashcopy” operation. A flashcopy operation provides the appearance of an instant copy between a source volume and a target volume within a storage sub-system such as the storage sub-system 200 . A flashcopy operation conducts data transfers from a source volume to the target volume at the convenience of the storage sub-system 200 without halting access to the source or target volumes by an external device, such as a host or server.
[0034] The challenge of conducting flashcopy operations and their associated background copy operations is in maintaining the integrity of the source and target volumes in light of on-going read, write, and delete operations to the source and target volumes. The aforementioned co-pending application of John A. Hulsey entitled METHOD FOR MANAGING FRESPACE WITH DATA SET LEVEL FLASHCOPY discloses methods and means for conducting flashcopy operations on a sub-volume basis that may be used in conjunction with the present invention to increase the usefulness thereof. As such, the aforementioned application is hereby incorporated by reference into this document. Data integrity is maintained during flashcopy operations by tracking changes that occur to the source volume. A need currently exists for a method to leverage the tracking features of flashcopy operations in order to conduct incremental backup operations in an efficient, host-independent manner.
[0035] Referring to FIG. 2 b , a backup capable controller 220 of the present invention facilitates conducting incremental backup operations from a source volume to a target device in a host-independent manner. The controller 220 in the depicted embodiment includes a transfer module 260 that enables the transfer of data between devices, a tracking module 270 that tracks the movement and placement of the data on a block level, and a metadata buffer 280 for collecting metadata describing block-level operations. In one embodiment, the modules of the controller 220 are software modules programmed to conduct their designated tasks.
[0036] The transfer module 260 coordinates data transfers between source and target volumes. In one embodiment, the transfer module 260 conducts handshaking with the storage devices 230 in a manner that validates the reliability of data transfers. The tracking module 270 tracks the movement and placement of data involved in flashcopy and backup operations. In one embodiment, the tracking module 270 uses bit flags to mark and unmark regions containing data involved with flashcopy or backup operations.
[0037] A metadata buffer 280 contains metadata describing block-level operations related to block-level data involved with flashcopy and/or backup operations. In one embodiment, the metadata includes a block index and an operation code indicating the type of operation associated with the block. In one embodiment, the data within the metadata buffer is a variable-sized log of changes to specified data blocks such as those associated with a volume designated for backup. In another embodiment, the metadata buffer is a fixed-sized table indicating the status of each data block that is tracked.
[0038] [0038]FIG. 3 is a flow chart illustrating one embodiment of a host-independent incremental backup method 300 of the present invention. The backup method 300 facilitates efficient incremental block-level backups of data within a storage subsystem without requiring bookkeeping operations within the host or filesystem that keep track of read, write, and delete operations. Although the backup method 300 may be conducted on a sub-volume level, for clarity purposes the description of the backup method 300 generally assumes block-level backup of an entire volume.
[0039] As depicted, the backup method 300 includes a mark snapshot instance step 310 , a conduct flashcopy step 320 , an initiate background transfer step 330 , a collect metadata step 340 , a snapshot requested test 350 , and a termination requested test 360 . Although for purposes of clarity the steps of the backup method 300 are depicted in a certain sequential order, execution within a actual system may be conducted in parallel and not necessarily in the depicted order.
[0040] The backup method 300 is typically invoked in conjunction with conducting a baseline backup and typically loops through once for the initial or baseline backup and once for each subsequent (i.e. incremental) backup. Alternately, the backup method 300 may be partitioned into separate routines for initial (full) backups and subsequent (incremental) backups. Preferably, any data caches on the host or elsewhere are flushed previous to invoking the backup method 300 to ensure the integrity of the file system.
[0041] The mark snapshot instance step 310 marks the instance of the backup for purposes of restoration. In one embodiment, marking the snapshot instance involves saving a timestamp indicating the time of the backup along with additional data indicating the volume (or portion thereof) involved in the backup. In certain embodiments, marking the snapshot instance may also involve saving a pointer that marks the current insertion position of the metadata buffer 280 .
[0042] The depicted backup method 300 proceeds from the mark snapshot instance step 310 to the conduct flashcopy step 320 . The flashcopy step 320 conducts an instant copy from a primary volume (or a portion thereof) to a secondary volume. Rather than conducting actual data transfers between the primary and secondary volume, the conduct flashcopy step 320 preferably initiates tracking of operations that effect the primary volume. Access to the secondary volume (i.e. the flashcopy target) is redirected to the primary volume. In the event of a write operation to the primary volume, for example by a host, the original data from the primary volume is transferred to the secondary volume to preserve the original data and thereby maintain the integrity of the secondary volume.
[0043] Using an actual flashcopy command to implement step 320 is not required but maybe a convenient method to track changes to the original data and facilitates using a common code base for flashcopy and backup operations.
[0044] The initiate transfer step 330 initiates the transfer of data from the secondary volume to the backup device or subsystem. In one embodiment, the transfers are conducted as a background task. With an initial backup, the entire secondary volume is transferred to the backup device. With each subsequent backup, only those blocks that have changed on the primary volume since the previous backup operation are transferred to the backup device.
[0045] The collect metadata step 340 collects metadata describing operations that change the primary volume so that the subsequent backups can use the metadata to determine which data blocks should be transferred to the backup device. In certain embodiments, the metadata corresponds to data used to track changes related to flashcopy operations. In those embodiments, the collect metadata step may occur automatically in conjunction with the conduct flashcopy step 320 and need not be done separately.
[0046] The snapshot requested test 350 ascertains whether a snapshot command related to the primary volume (or portion thereof) has been issued. If so, the backup method 300 loops to the mark snapshot instance step 310 , otherwise the method proceeds to the termination requested test 360 . The termination requested test 360 ascertains whether termination of the specific backups related to the primary volume (or portion thereof) has been requested, for example, by the host. If so, the backup method 300 ends 370 . Otherwise the method loops to the collect metadata step 340 and continues operation.
[0047] Essentially, the backup method 300 conducts a virtual instant copy (i.e. a flashcopy) operation to a secondary volume in order to continue access to the primary volume and effectively freeze the volume contents on the secondary volume while data is transferred from the secondary volume to the backup device. Actual access to the secondary volume is is redirected to the primary volume except for data that has been transferred to the secondary volume in response to write operations on the primary volume. With the initial snapshot, the entire contents of the (frozen) secondary volume is written to the backup device or subsystem. With subsequent snapshots, only data blocks that have changed on the primary volume between the previous snapshot instance and the current snapshot instance are written to the backup device or subsystem.
[0048] [0048]FIG. 4 is a block diagram illustrating the results of one embodiment of the method of FIG. 3. The diagram features an instance table 410 , a metadata buffer 420 , and a backup image 430 . The depicted data structures illustrate one example of the results of one embodiment of the backup method 300 . The depicted structures data contained therein may be used to restore the primary volume (or portion thereof) to a specific image corresponding to a specific snapshot instance.
[0049] The depicted instance table 410 contains a timestamp indicating the time of the backup, a pointer 425 that marks the current insertion position of the metadata buffer, a pointer 435 that marks the current insertion position on the backup device, and additional data indicating the volume (or portion thereof) involved in the backup. The depicted metadata buffer 420 contains metadata describing operations that changed blocks between snapshot instances.
[0050] The pointers 425 from the depicted instance table 410 partition the depicted metadata buffer 420 into metadata intervals 440 a to 440 h . The depicted backup image 430 is also partitioned into regions 450 a to 450 h corresponding to the metadata intervals 440 a to 440 h . The pointers 435 point to specific regions 450 of the backup image 430 and facilitate recovery of the primary volume to a specific snapshot instance. Although the regions 450 are shown in contiguous sequential order, they need not be in contiguous sequential order on the actual backup device.
[0051] Preferably, the backup image 430 contains the information contained within the instance table 410 and the metadata buffer 420 or similar information, in order to facilitate restoration solely from the backup image 430 . For example, in certain embodiments the regions 450 are prefaced with the specific entry from the instance table 410 that corresponds to the particular region 450 along with the metadata from the corresponding metadata interval 440 .
[0052] The present invention increases the efficiency of conducting backup operations and off-loads such operations from the host. In particular, bookkeeping by the file system or backup manager to track those files that have changed since a previous backup need not occur. The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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Block-level operations are tracked within a storage subsystem. Metadata corresponding to the block-level operations are collected within the storage subsystem between snapshot (i.e., backup) instances. The collected metadata are referenced to ensure that only overwritten data blocks are copied to the backup device. The present invention leverages the capabilities of flashcopy operations, frees the host from costly housekeeping tasks, and facilitates efficient backup operations independent of a host or filesystem.
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BACKGROUND OF THE INVENTION
[0001] I. Field of the Invention
[0002] The present invention relates to an apparatus for the attachment of a shaft, particularly that of a rotating control device, to an operating unit or actuator drive system. More particularly, the invention concerns a device of the class that includes a centering shaft adapter in which separate mechanisms are used to (1) accommodate shafts of varying sizes while keeping any shaft concentric with the hub of a rotating actuator or drive system attached to the adapter and to (2) generate the clamping force required to transfer the torque load between the shaft and the adapter.
[0003] II. Related Art
[0004] Many control devices include motors driving rotating hubs usually having meshing splines of a given pitch which, in turn, are used to operate a concentrically aligned rotary axle or shaft of a control device such as a butterfly ventilating valve, damper, or the like. An integral adapter device is used to directly couple the rotating output hub to an input shaft of a control device in concentric arrangement. The drive units are designed to be used with a variety of input or control device shaft sizes. However, generally in the past, it has been necessary to provide special arrangements in order to change shaft sizes. For example, a series of adapters might be used to accommodate shafts of different sizes to enable the system to maintain the desired concentric arrangement. Alternatively, a plurality of separate inserts have been devised, one for each size shaft to space the shaft from the clamp jaws the appropriate amount to maintain a concentricity with the output hub of the actuator.
[0005] Mechanical clamping devices also exist which adjust the center of the clamped shaft to maintain concentricity with a corresponding hub over a range of shaft sizes. One such device is illustrated and described in U.S. Pat. No. 5,544,970 to Studer which utilizes a hollow member having internal and external threads which cooperate to open and close upper and lower jaw members to clamp about a shaft of interest. The outer threads engage an outer housing member which, in turn, operates the lower jaw; whereas the inner threads engage a bolt that pulls on the upper jaw. A thread pitch ratio between the inner and outer threads is used to move the jaws an unequal amount so that the center between the jaws remains concentric with the axis of the hub. Although this successfully accomplishes the desired adjustment, the design has several drawbacks or limitations. First, the centering mechanism must also supply the clamping force so that it must be built to transmit the entire system torque; and second, the double-threaded member is difficult to produce and involves the utilization of a very fine pitch on the outside thread which is readily susceptible to clogging and cross threading.
[0006] Thus, there remains a definite need in the art for an adaptive coupling mechanism that utilizes parts that are readily made and provides a separate mechanism for the clamping and centering functions and which can accommodate a wide range of shaft sizes.
SUMMARY OF THE INVENTION
[0007] The present invention provides a single, relatively simple mechanism for concentrically adapting the output hub of a direct coupled actuator to operate control device shafts of varying sizes, thereby obviating the need for separate connecting devices or inserts to accommodate a range of shaft sizes. In this manner, a direct coupled actuator can be mounted on shafts of different sizes interchangeably while maintaining concentric alignment between the output hub of the actuator and the shaft of interest. In addition to being a self-centering shaft adapter, the adapter of the invention utilizes separate mechanisms to keep the shaft and output hub concentric and to generate the clamping force required to transfer the torque load from the shaft to the adapter. In this manner, the self-centering mechanism is not required to transmit the full torque load between the adapter and the clamped shaft but only to keep the shaft and output hub concentric. The system consists of opposed jaws that grip each side of the shaft and are mechanically linked to insure that both jaws travel in equal amounts with respect to the geometric center of an integral drive hub when adjusted to accommodate a shaft that is being clamped.
[0008] The mechanism may take any of several forms including double and single rack and pinion systems, beam systems, and cam and follower devices. Each of these mechanisms operates to concentrically open and close a pair of clamping jaws about a geometric center using a mechanical linkage operated by a conventional threaded fastening arrangement, as will be described.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the drawings, wherein like numerals designate like parts throughout the same:
[0010] [0010]FIG. 1 is an exploded perspective view of one embodiment of the self-centering shaft adapter of the invention centered utilizing a rotating cam system;
[0011] [0011]FIG. 2A is an exploded perspective view of an alternate embodiment of the self-centering shaft adapter of the invention also employing a cam system;
[0012] [0012]FIG. 2B is a top plan view of the embodiment of FIG. 2A in an assembled state;
[0013] FIGS. 2 C- 2 E represent various sectional views of the embodiment of FIGS. 2A and 2B, as noted on the drawings;
[0014] [0014]FIG. 3A is a top plan view of another embodiment of the self-centering shaft adapter of the invention utilizing a single pinion rack and pinion centering system;
[0015] [0015]FIG. 3C is a bottom end view of the embodiment of 3 A;
[0016] [0016]FIGS. 3B, 3D and 3 E represent sectional views noted on FIGS. 3A and 3C;
[0017] [0017]FIG. 4A is a partially cut-away top view of an alternate embodiment showing internal parts and employing a pair of rack and pinion systems;
[0018] [0018]FIG. 4B is a bottom view of FIG. 4A;
[0019] [0019]FIG. 5 is a top view of yet another embodiment which utilizes a beam-type centering arrangement; and
[0020] [0020]FIG. 6 is an exploded perspective view of an embodiment similar to that shown in FIG. 1 with certain modifications.
DETAILED DESCRIPTION
[0021] The following detailed description describes a variety of implementations of the self-centering shaft adapter of the invention which employ several different mechanisms. Each uses a relatively simple mechanical system to maintain concentricity between integral drive hub and control shaft which should have a long reliable life without the need for expensive, tight tolerance parts. Each of the embodiments also embraces the concept that the self-centering aspect of the mechanism which keeps the shaft and hub concentric is not used to generate the clamping force required to transfer the torque load between the clamped shaft and the shaft adapter. The following embodiments are presented as exemplary of the invention but are not meant to limit the scope of the concept in any manner. When referring to the clamping jaws or other parts of the system, the terms “upper” and “lower” refer to parts of the device as drawn and not to any particular mounted orientation.
[0022] [0022]FIG. 1 is an exploded perspective view illustrating one embodiment of a self-centering shaft adapter of the invention which employs centering cams in conjunction with opposed jaw clamps whose separation is controlled by a spring-biased T-bolt and nut. The system, generally at 20 , includes an upper housing 22 and a lower housing 24 together with a generally U-shaped inner (upper) jaw clamp device 26 which has generally parallel spaced sides 28 and 30 and which is designed to be contained within and slide relative to the spaced parallel sides 32 and 34 of a rather larger generally U-shaped outer (lower) jaw clamp member 36 .
[0023] The spaced parallel sides of upper jaw clamping member 26 include parallel clamping or toothed fractions 40 and the lower jaw member 36 is provided with opposed similar toothed fractions at 42 . A T-bolt 44 with flattened anti-rotation head portion 46 is designed to slip through openings 48 and 50 in respective members 26 and 36 when the upper jaw clamp 26 is assembled into the lower jaw clamp 36 and nut 52 is threaded on the protruding end thereof. The opposed shaped toothed fractions 40 and 42 are caused to converge and diverge by rotation of nut 52 aided by a compression spring 54 which slides over T-bolt 44 .
[0024] The system is further provided with a pair of generally flat washer-shaped spaced centering cam members 56 and 58 . The centering cam device 58 is provided with a pair of follower pins 60 and 62 located on the same side of the cam member 58 spaced 180° apart and extending perpendicular to the plane of the cam member. The cam device 58 is designed to nest in a recess 61 in lower housing 24 and rotate relative thereto. The parallel sides 28 and 30 of upper (inner) jaw member 26 are provided with aligned notches or slots 64 on one side thereof and with elongate recesses, one of which is shown at 66 on the other. The lower (outer) jaw member 36 is likewise provided with aligned notches or slots, one of which is shown at 68 , and recesses 70 , but is designed to be assembled in opposite side-to-side relation with respect to jaw member 26 as shown in FIG. 1. Holes 72 provided in the centering cam member 56 are designed to align with and entertain the pins 60 and 62 in the device as assembled. A driving hub 74 provided with splines (not shown) is fashioned integral with the lower housing member 24 . Threaded devices such as machine screws (not shown) can be used to assemble the housing members 22 and 24 capturing the intermediate parts therebetween.
[0025] In operation, tightening of the nut 52 draws the upper and lower toothed jaw portions 40 and 42 closer together. (Note that the T-bolt head 46 is shaped with flat sides so that it cannot rotate within the lower U-portion of the upper clamp 26 .) As is apparent from the figure, at the same time, the movement of the jaw clamps 26 with slots 64 causes the pins 60 , 62 to rotate counterclockwise and, in turn, operate via slot 68 to displace the lower jaw member 36 an equal distant amount in the opposite direction. In this manner, using the spring 54 to maintain tension, the device will properly center about any shaft inserted through the jaws within the limits of its clamping capacity size.
[0026] A somewhat similar arrangement in an alternate embodiment is depicted in the several views of FIGS. 2 A- 2 E. As seen generally at 80 , in the exploded view of FIG. 2A, there is provided a lower housing 82 configured to receive an upper housing 84 . U-shaped inner (upper) jaw clamp 86 and U-shaped outer (lower) jaw clamp 88 , T-bolt 90 , nut 92 and compression spring 94 are also shown. A single centering cam member 96 configured to nest in a recess 98 in the lower housing 82 is provided with a pair of opposed (180° apart) raised extensions or tabs 100 (see FIG. 2D). The upper (inner) jaw 86 is provided with a notch 102 and cutout 104 (FIG. 2D) in the lower flange; and the lower flange of the outer (lower) jaw clamp 88 is likewise constructed in opposite relation with notch 106 and recess 108 . A shaft to be captured is pictured at 110 and a splined integral driving hub is shown attached to the outer housing at 112 . As was the case with the embodiment of FIG. 1, the centering cam member 96 with raised tabs 100 operates in conjunction with the notches 102 , 106 in the respective jaws 86 and 88 to center a shaft of any diameter as at 110 with respect to the hub 112 (FIG. 2E).
[0027] FIGS. 3 A- 3 E depict another embodiment which accomplishes shaft diameter-independent centering using a rack and pinion system. That device includes housing members 120 and 122 enclosing the U-shaped upper (inner) jaw 124 and lower (outer) U-shaped jaw 126 shown capturing a shaft 128 . A clamping bolt 130 with nut 132 and biasing compression spring 134 are included. This embodiment is further provided with a pinion 136 mounted on a fixed shaft 138 and designed to rotate about the shaft in response to the movement of a pair of spaced rack members 140 and 142 , respectively fixed to the upper (inner) and lower (outer) jaw members 124 and 126 . In this manner, movement of the jaw in equal distance in opposite directions is assured as they are opened and closed about a shaft at 128 by rotation of the nut 132 . As with other embodiments, the outer housing is attached to the output hub of a direct coupled actuator. Also, as with the other embodiments, all of the clamping force is provided by the bolt and nut system whereas the operating torque is transmitted between the interface of the jaws and the housing.
[0028] [0028]FIGS. 4A and 4B depict an alternate form of a rack and pinion operated self-centering device using dual rack and pinion systems. The device includes a U-bolt 150 carried in a frame member 151 carrying an upper or inner casting 152 which, in turn, includes a jaw member 154 and a lower or outer casting 156 which carries a lower jaw 158 . A pair of pinions 160 , 162 carried on shafts 164 , 166 fixed to the outer housing (not shown) engage respectively upper and lower rack portions 168 , 170 and 172 , 174 on either side of the upper or inner casting 152 . Clamping is provided by a pair of nuts 176 attached to the ends 178 of U-bolt 150 .
[0029] [0029]FIG. 5 illustrates a beam version of a self-centering shaft adapter and includes an outer housing 200 in which is mounted a U-shaped upper jaw 202 , a U-shaped lower jaw 204 , the jaws having respective shaft engaging teeth 206 and 208 . Reciprocal operation for opening and closing the jaws is provided by a T-bolt 210 with nut 212 and biasing compression spring 214 in the manner of previously described embodiments as discussed above in regard to FIGS. 1 - 3 . A pivot arm 216 is provided which is mounted on a pivot shaft 218 fixed to the outer housing through a clearance slot 220 . End 222 of pivot arm 216 is provided with a pin 224 which engages a slot 226 in the upper jaw 202 . End 228 is provided with a pin 230 which engages a slot 232 in the lower jaw 204 . This system allows centering adjustment as the jaws are opened and closed to accommodate different diameter shafts.
[0030] In the exploded perspective view of FIG. 6, there is illustrated a cam-operated embodiment similar to that shown in FIG. 1 and FIG. 2A- 2 E, but in a somewhat simplified and more compact form. This embodiment, generally at 300 , includes an upper housing 302 and a lower housing 304 which includes an integral driving hub 306 with outer splines 308 adapted to be received in a driving actuator mechanism (not shown). A generally U-shaped inner (upper) jaw clamp member 310 with spaced parallel sides 312 , 314 is designed to be contained within and slide reciprocally relative to the spaced parallel sides 316 , 318 of an outer (lower) U-shaped jaw clamp member 320 . The spaced parallel sides 312 , 314 , 316 and 318 include respective opposed parallel toothed fractions 322 and 324 which are designed to converge and clamp a shaft of interest therebetween.
[0031] The jaw clamp members 310 and 320 are retained and operated to open and close using an internally threaded member 326 having projections 328 press fit into matching openings 330 in the base of inner (upper) jaw clamp member 310 . A partially threaded bolt device 332 carried within and free to rotate relative to outer (lower) jaw clamp member 320 is designed to be threaded into member 326 at 334 and is used to adjust the span of the jaw clamp members 310 and 320 . The bolt device 332 is retained within the lower jaw 320 by a hollow member 335 in which it is free to rotate. No spring is necessary as the jaws are easily pried apart by hand, however, one can be provided if desired.
[0032] Notches or slots 336 are aligned on one side of base parallel sides 312 and 314 of upper jaw clamp member 310 and in the opposite side (as assembled) of base sides 316 , 318 of lower jaw clamp member 320 at 338 . Corresponding accommodating clearance recesses are notched in the jaw clamp member sides opposite the notches at 340 and 342 . A single round, relatively flat cam member 344 having a central opening 346 , which aligns with central openings 348 and 350 in upper and lower housing members 302 and 304 , respectively, carries a pair of opposed follower pins 352 , 354 on the opposite side thereof and spaced 180° apart. The pins extend perpendicular to the plane of the cam element 344 . The housing is fastened together using threaded fasteners 356 .
[0033] This system operates in the same manner as the embodiment of FIG. 1 with the follower pins 352 and 354 extending through the notches 336 and 338 in jaw members 310 and 320 , and the relative movement of the jaw members 310 and 320 operating through the pins to rotate the cam member 344 so that the upper and lower jaw movement is equal distance from the center of a captured shaft which, in turn, remains co-incident with the center line of the driving hub 306 .
[0034] It should be noted that in this embodiment, the threaded adjustment device 332 need not protrude beyond the confines of the housing making the system more compact. The housing member 302 is provided with curved slots 358 and lower member 304 with curved slots 360 which accommodate and guide the follower pins 352 and 354 eliminating the need for a second cam element.
[0035] This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices, and that various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
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An adapter for detachably concentrically coupling shafts having a range of diameters to a rotating input actuator capable of rotating about a rotational axis is disclosed in which the force to transfer rotational torque between said shaft and a rotating input actuator to which said housing is attached is generated independent of said self-centering adjustment system.
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CROSS-REFERENCE TO RELATED APLICATION
[0001] The present application claims the benefit of 35 U.S.C. 111(b) Provisional application Ser. No. 60/004,061 filed Sep. 20, 1995, and entitled Catheters and Methods Detecting Thermal Discrepancies in Blood Vessels.
[0002] This invention was made with government support under Grant No. 91HL07 awarded by the National Heart Lung and Blood Institute, giving the federal government certain rights in the invention. In addition, the invention described herein was made in the performance of work under a NTASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457).
BACKGROUND OF THE INVENTION
[0003] A. Field of the Invention
[0004] This invention relates to the medical diagnosis and treatment of arterial disease by means of temperature differential sensing, and particularly, infrared-sensing with devices such as temperature probes, cameras, and catheters. In particular, the invention provides catheters and methods of using catheters to diagnose arterial diseases detectable by thermal discrepancies in the arterial wall.
[0005] B. Description of the Related Art
Problems in Diagnosis
[0000] Plaque Physiology
[0006] Atherosclerotic coronary artery disease is the leading cause of death in industrialized countries. An atherosclerotic plaque is a thickened area in the wall of an artery. Typically, patients who have died of coronary disease may exhibit as many as several dozen atherosclerotic plaques; however, in most instances of myocardial infarction, cardiac arrest, or stroke, it is found that only one of these potential obstructions has, in fact, ruptured, fissured, or ulcerated. The rupture, fissure, or ulcer causes a large thrombus (blood clot) to form on the inside of the artery, which may completely occlude the flow of blood through the artery, thereby injuring the heart or brain. A major prognostic and diagnostic dilemma for the cardiologist is how to predict which plaque is about to rupture.
[0007] Most ruptured plaques are characterized by a large pool of cholesterol or necrotic debris and a thin fibrous cap with a dense infiltration of macrophages. The release of matrix-digesting enzymes by the cells is thought to contribute to plaque rupture. Other thromboses are found on non-ruptured but inflamed plaque surfaces.
[0008] Inflammation in an arterial plaque is the result of a series of biochemical and mechanical changes in the arterial wall. Plaque, a thickening in the arterial vessel wall results from the accumulation of cholesterol, proliferation of smooth muscle cells, secretion of a coliagmous extracellular matrix by the cells, and accumulation of macrophages and, eventually, hemorrhage (bleeding), thrombosis (clotting) and calcification. The consensus theory is that atherosclerotic plaque develops as a result of irritation or biochemical damage of the endothelial cells.
[0009] The endothelial cells which line the interior of the vessel prevent inappropriate formation of blood clots and, inhibit contraction and proliferation of the underlying smooth muscle cells. Most investigators believe that atherosclerotic plaques can develop when endothelial cells are damaged or dysfunctional. Dysfunction in endethelial cells is typically produced as a result of injury by cigarette smoke, high serum cholesterol (especially oxidized low density lipoprotein), hemodynamic alterations (such as those found at vessel branch points), some viruses (herpes simplex, cytomegalovirus) or bacteria (e.g., Chlamydia), hypertension, some hormonal factors in the plasma (including angiotensisn II, norepinephrine), and other factors as yet unknown. As a result of these gradual injuries to the endothelial cells, an atherosclerotic plaque may grow slowly over many years. However, it is now well documented that if a plaque ruptures, it often grows abruptly.
[0010] When plaque rupture develops, there is hemorrhage into the plaque through the fissure where the surface of the plaque meets the bloodstream. Blood coagulates (forms a thrombus) quickly upon contact with the collagen and lipid of the plaque. This blood clot may then grow to completely occlude the vessel or it may remain only partially occlusive. In the latter case, the new clot quite commonly becomes incorporated into the wall of the plaque, creating a larger plaque.
[0000] Plaques At Risk of Rupturing
[0011] Considerable evidence indicates that plaque rupture triggers 60% to 70% of fatal myocardial infarctions and that monocyte-macrophages contribute to rupture by releasing metalloproteinases (e.g., collagenases, stromelysin) which can degrade and thereby weaken the overly fibrous cap. Van der Wal, et al., Circulation 89:36-44 (1994); Nikkari, et al., Circulation 92:1393-1398 (1995); Falk, et al., Circulation 92:2033-20335 (1995); Shah, et al., Circulation 244 (1995); Davies, et al., Br Heart J 53:363-373 (1985); Constantinides, J Atheroscler Res 6:1-17 (1966). In another 25% to 30% of faal infarctions, the plaque does not rupture, but beneath the thrombus the endothelium is replaced by monocytes and inflammatory cells. Van der Wal, et al., Circulation 89:36-44 (1994); Farb, et al., Circulation 92:1701-1709 (1995). These cells may both respond to and aggravate intimal injury, promoting thrombosis and vasoconstriction. Baju, et al., Circulation 89:503-505 (1994).
[0012] Unfortunately, neither plaque rupture nor plaque erosion is predicable by clinical means. Soluble markers (P-selectin, von Willebrand factor, angiotensen-inverting enzyme, C-reactive protein, D-dimer; Ikeda, et al., Circulation 92:1693-1696 (1995); Merlini, et al., Circulation 90:61-8 (1994); Berk, et al., Am J Cardiol 65:168-172 (1990)) and activated circulating inflammatory cells are found in patients with unstable angina pectoris, but it is not yet known whether these substances predict infarction or death. Mazzone, et al., Circulation 88:358-363 (1993). It is known, however, that the presence of such substances cannot be used to locate the involved lesion.
[0013] Low-shear regions opposite flow dividers are more likely to develop atherosclerosis, (Ku, et al., Arteriosclerosis 5:292-302 (1985)), but most patients who develop acute myocardial infarction or sudden cardiac death have not had prior symptoms, much less an angiogram. Farb, et al., Circulation 92:1701-1709 (1995).
[0014] Certain angiographic data has revealed that an irregular plaque profile is a fairly specific, though insensitive, indicator of thrombosis. Kaski, et al., Circulation 92:2058-2065 (1995). These stenoses are likely to progress to complete occlusion, while less severe stenoses are equally likely to progress, but less often to the point of complete occlusion. Aldeman, et al., J Am Coll Cardiol 22:1141-1154 (1993). However, because hemodynamically nonsignificant stenoses more numerous than critical stenoses and have not triggered collateral development, those which do abruptly occlude actually account for most myocardial infarctions. Ambrose, et al., J Am Coll Cardiol 12:56-62 (1988); Little, et al., Circulation 78:1157-1166 (1988).
[0015] Moreover, in postmortem studies, most occlusive thrombi are found over a ruptured or ulcerated plaque that is estimated to have produced a stenosis of less than 50% in diameter. Shah, et al., Circulation 244 (1995). Such stenoses are not likely to cause angina or a positive treadmill test. (In fact, most patients who die of myocardial infarction do not have three-vessel disease or severe left ventricular dysfunction.) Farb, et al., Circulation 92:1701-1709 (1995).
[0016] In the vast majority of plaques causing a stenosis less than or equal to 50%, the surface outline is uniform, but the deep structure is highly variable and does not correlate directly with either the size of the plaque or the severity of the stenosis. Pasterkamp, et al., Circulation 91:1444-1449 (1995); Mann and Davies Circulation 94:928-931 (1996).
[0017] Certain studies have been conducted to determine the ability to identify plaques likely to rupture using intracoronary ultrasound. It is known that (1) angiography underestimates the extent of coronary atherosclerosis, (2) high echo-density usually indicates dense fibrous tissue, (3) low echo-density is a feature of hemorrhage, thrombosis, or cholesterol, and (4) shadowing indicates calcification. Yock, et al., Cardio 11-14 (1994); McPerhson, et al., N Engl J Med 316:304-309 (1987). However, recent studies indicate that intra-vascular ultrasound technology currently cannot discriminate between table and unstable plaque. De Feyter, et al., Circulation 92:1408-1413 (1995).
[0018] The rupture process is not completely understood, but it is known that the plaques most likely to rupture are those that have both a thin collagen cap (fibrous scar) and a point of physical weakness in the underlying plaque. It is known that plaques with inflamed surfaces or a high density of activated macrophages and a thin overlying cap are at risk of thrombosis. Van der Wal, et al., Circulation 89:36-44 (1994); Shah, et al., Circulation 244 (1995); Davies, et al., Br. Heart J 53:363-373 (1985); Farb, et al., Circulation 92:1701-1709 (1995); Van Damme, et al., Cardiovasc Pathol 3:9-17 (1994). Such points are thought to be located (as determined by modeling studies and pathologic analysis) at junctures where pools of cholesterol meet a more cellular and fibrous part of the plaque. Typically, macrophages (inflammatory cells), which produce heat, have been found at these junctures. Since these inflammatory cells release enzymes capable of degrading the collagen and other components of the extracellular matrix, it is thought that they are crucial to the process of plaque rupture or fissuring.
[0000] Transplant Vasculopathy
[0019] Inflammation also plays an important role in the rejection of transplanted organs, a process which begins by an attack of host T lymphocytes in the grafted donor organ's endothelial cells. Yeung et al. J. Heart Lung Transplant. 14:S215-220 (1995); Pucci et al. J. Heart Transplant. 9:339-45 (1990); Crisp et al. J. Heart Lung Transplant. 13:1381-1392 (1994). Recruitment and proliferation of inflammatory and smooth muscle cells are heat-generating processes, whose effects are detectable in adamance of the detection of vessel narrowing using stress tests, ultrasound, or angiography. Johnson et al. J. Am. Coll. Cardiol. 17: 449-57 (191); St. Goar et al. Circulation 85:979-987 (1992). In addition to the host attack of “non-self” antigens of the donor organs, many transplanted tissues develop cytomegalovirus infections, an event that is also heat-generating. Grattan et al. JAMA 261:3561-3566 (1989). These events in transplant physiology are ones for which it would be valuable to track in patients recovering from such surgery.
[0000] Restenosis
[0020] Another serious problem in diagnostic cardiology is restenosis, a renarrowing of an artery that has undergone one or more interventional techniques to relieve an original stenosis (caused by plaque). Such techniques include balloon angioplasty, atherectomy (shanking or cutting the plaque), and laser angioplasty. Balloon angioplas of the coronary arteries is a major advance in treatment and has been performed on hemodynamically significant coronary stenoses (those that are 70% to 99% of the cross-sectional diameter of thevessel) with a success rate of 90%. In about 40% of the patients, however, restenosis occurs in the vessel and most of the benefit gained by the procedure is lost. Thus, another major diagnostic and prognostic dilemma for cardiologists not readily addressed by prior art devices or methods is predicting which patients will develop restenosis.
[0021] Restenosis may occur when the removal of plaque by angioplasty or atherectomy injures the artery wall. The injury to the vessel wall causes the smooth muscle cells at that site to proliferate and to secrete an extracellular matrix which again narrows the artery. Both cell proliferation and secretion are exergonic (heat-generating) processes. Additionally, it is known that macrophage concentration in a vessel is correlated to the risk of restenosis.
[0022] Many factors have been reported to predict which patients will develop restenosis. However; these studies are markedly at odds with each other and no factor has been strongly predictive of the restenosis process. Thus, cigarette smoking, hypertension, hypercholesterolemia, unstable angina, age. sex and many other factors have been only weakly predictive, at best.
Prior Art Devices/Methods
[0023] A number of approaches and devices have been proposed to diagnose or treat vascular obstructions. U.S. Pat. No. 3,866,599 relates to a fiberoptic catheter for insertion into the cardiovascular system for the measurement of oxygen in blood. For the purpose of detecting oxygenation levels in the blood, optical fibers are used to first project infra-red and red light at the catheter tip into the blood. The infra-red and red light reflected by the blood is then returned through the optical fibers to an oximeter. The ratio of infra-red light reflected to that absorbed by the blood is proportional to the oxygen saturation in the blood. This catheter design is also one wherein there is at the distal end of the element a recess preventing the ends of the fibers from contacting the vessel wall and an exterior sleeve which can be expanded to further space the fibers from the wall of that vessel. However, the fiberoptic catheter of this patent does not permit detection of heat.
[0024] In some prior art devices, temperature sensing elements have been used. U.S. Pat. No. 4,752,141 relates to fiberoptic sensing of temperature and/or other physical parameters using a system comprising (1) an optical fiber (2) means including a source of visible or near visible electromagnetic radiation pulses at one end of the fiber for directing the radiation along the fiber to another end of the fiber (3) a sensor positioned at or near the end of the fiber in a manner to receive the radiation, modulate it by the temperature, and redirect the modulated radiation back through the optical fiber to the sensor (4) the sensor comprising at least one optical element in the path of the source of radiation whose optical properties vary in response to the magnitude of temperature changes and (5) means positioned at the end of the fiber receiving the modulated radiation for measuring a function related to the time of the resulting luminescent radiation intensity decay after an excitation pulse indicating the temperature of the sensor. These temperature sensors were designed to physically contact a surface and were built with an elastomeric substance at the end of the fiber to which a thin layer of phosphor material had been deposited. The phosphor reacts to the temperature and emits radiation which travels up the fiber and is detected by the sensor. Contact temperature determinations require the ability of the catheter to be placed in contact with the locus whose temperature is to be measured.
[0025] U.S. Pat. No. 4,986,671 relates to a fiber optic probe with a single sensor formed by a elastomeric lens coated with a light reflective and temperature dependent material over which is coated a layer of material that is absorptive of infrared radiation thereby allowing a determination of characteristics of heat or heat transfer. One application is in a catheter for providing pressure, flow and temperature of the blood in a blood vessel.
[0026] Other methods utilizing differing means for heat detection are known. The sensitivity and/or toxicity of these devices is unknown. U.S. Pat. No. 4,140,393 relates to the use of birefringement material as a temperature probe. U.S. Pat. No. 4,136,566 suggests the use of the temperature dependent light absorption characteristics of gallium arsenide for a temperature sensor. U.S. Pat. No. 4,179,927 relates to a gaseous material having a temperature dependent light absorption.
[0027] Other approaches utilize excitation techniques to detect heat. U.S. Pat. No. 4,075,493 relates to the use of a luminescent material as a temperature sensor, exciting radiation of one wavelength range being passed along the optical fiber from the measuring instrument, and temperature dependent luminescent radiation being emitted from the sensor back along the communicating optical fiber for detection and measurement by the instrument. It is the luminescent sensor technology which has found the greatest commercial applicability in fiber optic measurements, primarily for reasons of stability, wide temperature range, ability to minimize the effect of non-temperature light variations, small sensor size and the like.
[0028] An example of a luminescent fiberoptic probe that can be used to measure the velocity of fluid flow, among other related parameters, is given in U.S. Pat. No. 4,621,929. Infrared radiation is directed to the sensor along the optical fiber and is absorbed by a layer of material provided for that purpose. Once heated, the sensor is then allowed to be cooled by a flow of fluid, such cooling being measured by the luminescent sensor. The rate of cooling is proportional to the heat transfer characteristics and flow of the surrounding liquid.
[0029] U.S. Pat. No. 4,995,398 relates to the use of thermography during the course of by-pass heart surgery for the purpose of checking the success of the operation before closing the chest cavity. This patent describes the use of a scanning thermal camera, image processing, temperature differentials and displaying images in real time. The invention relies on the use of a cold injectate which when it mixes with warmer blood provides images captured on a thermal camera focusing on the heart to detect stenoses at the sit of distal anastomcses.
[0030] U.S. Pat. No. 5,646,501 relates to a method of identifying atherosclerotic plaque versus structurally viable tissues using a fluorescent beam at a single excitation wavelength of between 350 and 390 nm preferably from a laser which allows differentiation of these tissues. No catheter was used in the examples of the patent. Thus, in situ imaging is not disclosed or taught by this patent. Moreover, no technique is described by this patent for predicting plaque rupture, restenosis or transplant vasculopathy.
[0031] U.S. Pat. No. 5,057,105 relates to a hot tip catheter assembly comprising a heater, a cap, a thermocouple, power leads, and a central distal lumen to position the catheter in the artery. The thermocouple is included to continuously monitor the heating of the catheter tip in order to prevent overheating. The tip when properly placed on a plaque build up, melts the plaque.
[0032] U.S. Pat. No. 5,109,859 relates to ultrasound guided laser angioplasty comprising a laser at the tip of a catheter, an ultrasound device also at the tip of the laser for guidance, and a proximal occlusion balloon to provide stabilization and a blood free environment. This patent apparently also relates to estimating the mass of a plaque tissue. There is no teaching that the ultrasound device of the patent can distinguish histological features (i.e., what cells and extracellular matrix are within the plaque). Thus, it is not likely that such a device could be used to predict plaque rupture. Indeed, recent studies have found that intravascular ultrasound cannot identify which plaques are at risk of rupturing. de Feytia Circulation 92:1408-13 (1995).
[0033] U.S. Pat. No. 5,217,456 relates to an intra-vascular guidewire-compatible catheter which has a source of illumination and a synchronous fluorescence detector. Light in a wavelength that induces fluorescence in tissues emanates radially from an aperture on the side of the catheter. Fluorescence emitted from the tissues enters the catheter through the same aperture and is conveyed to a spectral analyzer. This information can be used to differentiate healthy tissue from atherosclerotic plaque. However, this device does not distinguish between plaque on the basis of heat differential.
[0034] U.S. Pat. No. 5,275,594 relates to methods and apparatus for distinguishing between atherosclerotic plaque and normal tissue by analyzing photoemissions from a target site, The system includes a source of laser energy for stimulation of fluorescence by non-calcified versus calcified atherosclerotic plaque, and an analyzing means for determining whether a spectrum of fluorescence emitted by a tissue represents calcified or non-calcified atherosclerotic plaque at a target site, based upon the time domain signal of calcium photoemission following fluorescent excitation of the calcium. When atherosclerotic plaque is identified, laser energy is used to ablate the plaque.
[0035] Prior art approaches to intravascular arterial diagnosis and repair have been numerous yet have failed to provide certain capabilities. In particular, such prior art catheters and methods have failed to provide means for detecting and treating atherosclerotic plaque since they have not been able to differentiate between those plaques at risk of rupturing and occluding and those that are not presently at such risk even it they are capable of determining the presence or absence of calcification of the plaque. Similarly, prior art approaches have not provided effective means for identifying specific arterial sites at risk for arterial restenosis after angioplasty or atherectomy. Prior art approaches have also failed to provide practical and effective means for detecting transplant vasculopathy. Neither have prior art approaches been able to effectively identify patients who have arterial wall areas of lower rather than higher temperature, such as areas of extensive scarring, lipid pools where there is no cellular infiltration, or areas of hemorrhage and thrombosis which have yet to be colonized by inflammatory cells.
SUMMARY OF THE INVENTION
[0036] The present invention overcomes at least some of the failures of the prior art by providing an infrared-sensing catheter for detecting heat-producing inflammatory cells and vessel wall cells, and thus predicting the behavior of injured blood vessels in medical patients. The catheters and methods of the present invention provide effective means for detecting and treating atherosclerotic plaque which is capable of differentiating between, among other pathologies, those plaques at risk of rupturing and occluding and those that are not presently at risk. The catheters and methods of the present invention also provide effective means for identifying specific arterial sites at risk for arterial restenosis after angioplasty or atherectomy, or which patients are at risk due to vasculopathy, or tissue rejection. The catheters and methods of the present invention also are capable of effectively identifying patients who have arterial wall areas of unusually low temperature and which represent previously undetected arterial at-risk areas—just as excess heat can identify regions at risk due to inflammation, sub-normal heat (areas cooler than the rest of a vessel) indicates a lack of actively metabolizing healthy cells (since heat in the body results from actively metabolizing cells). Non-cellular areas are typically regions of hemorrhage, thrombosis, cholesterol pools, or calcium—all indicators of high risk plaques. The invention's devices and methods achieve these ends by identifying and analyzing thermal discrepancies in the wall temperature of blood vessels.
[0037] The invention in one regard relates to apparatus for analyzing optical radiation of a vessel. In another regard, the invention relates to methods for analyzing optical radiation, which methods are best preferably achieved using the appartus of the invention.
[0038] Optical radiation of particular interest in the invention is that radiation which falls in the optical spectrum in the wavelength interval from about 2-14 μm. An attractive feature of infrared is its penetration through calcium (relative to white light and ultrasound). Benaron, et al., J Clin Monit 11:109-117 (1995).
[0039] The vessels of particular interest in the invention are those vessels where the access to a surface of which is problematic. Thus, where the internal diameter of a vessel is too small for ready access by a traditional temperature probe (i.e., a contact thermometer or thermocouple), the apparatus and methods of the invention will find utility. Similarly where the vessel, while of sufficiently large internal diameter for access by a temperature probe, has one or others of its openings narrowed, occluded or otherwise blocked, the apparatus and methods of the invention will find utility. Thus, of particular interest in application of the apparatus and methods of the invention are vessels of the body, including vessels circulating and transporting sera (i.e. blood) such as arteries, veins, sinuses, heart cavities and chambers.
[0040] The invention relates to apparatus and methods in which there is at least one optical fiber used which is capable of transmitting optical radiation from a distal end of the fiber, usually inside a vessel, to a proximal end of the fiber, usually outside the vessel. Optical fibers of the invention will exhibit certain key parameters related to their ability to transmit wavelengths in the region of 2-14 μm. These key parameters include optical transparency, flexibility and strength. The optical fibers of the invention are those which may be extruded in ultrathin diameters and which transmit over the appropriate infra-red spectral region. The infrared fiberoptic can be constructed from a variety of substances known to those of skill in the art such as zirconium fluoride (ZrF 4 ), silica, or chalcogenide (AsSeTe). ZrF 4 fibers are well suited to the apparatus and methods of the invention because such fibers have >90% transmission capabilities over 1 meter for small diameters.
[0041] The optical fibers useful in the apparatus and methods of the invention will also be ones capable of placement proximate to a locus of a wall of the vessel being investigated. This criterion is achieved in part by the flexibility of the fiber optic. In additional part, this criterion is met by the ultrathin nature of the diameter of the fiber optic.
[0042] The apparatus and methods of the invention also utilize a balloon which encases a distal end of the fiber. The balloon, in one embodiment, may be one which is transparent to the optical radiation of interest. In that instance, optical radiation originating outside the balloon is transmitted through the outer surface of the balloon to the inner surface of the balloon and on to the entry point for optical radiation into the optical fiber. It is important, in this embodiment, for there to be little if any absorption, reflection or other diversion of the optical radiation emanating from the source (i.e., the vessel wall, a locus such as a plaque locus) during its transmission through the surfaces of the balloon. Such unwanted absorption may be caused by blood or other body fluids. Therefore, transparency for purposes of the invention means an ability to transmit substantially all optical radiation from a particular source through the balloon surfaces to the optical fiber.
[0043] It is important, in this embodiment, for there to be substantially total conduction of the heat, while having substantially no loss of the heat emanating from the source (i.e., the vessel wall, a locus such as a plaque locus) as it contacts the outer surface of the balloon. Therefore, opacity (opaque) for purposes of the invention means an ability to absorb substantially all optical radiation from a particular source on the outer balloon surface. Thereafter, the inner surface of die balloon will re-emit a proportional amount of radiation to that absorbed on the outer surface immediately adjacent the locus originating the radiation. This re-emitted radiation will be detectable by the fiber optic system encased inside the balloon.
[0044] The apparatus and methods of the invention also utilize a detector capable of detecting a difference in the optical radiation of interest, between the locus and the average optical radiation along the vessel wall being investigated. In certain preferred embodiments, the detector of the invention is one which has a sensitivity capable of detection of differences in infra-red radiation as small as 50 °mK, and in the range of 10 to 100 °mK.
[0045] Where the balloon is one which is transparent to the radiation directly emitted from the locus or from the vessel wall portions outside the specific locus, the detector will be one capable of detecting the radiation which is transmitted through the balloon's outer and inner surfaces. Where the balloon is one which is opaque to the radiation directly emitted from the locus or from the vessel wall portions outside the specific locus, the detector will be one capable of detecting the radiation which is reemitted from the balloon's inner surface opposite the balloon's outer surface which is directly in contact with the locus.
[0046] In preferred embodiments the apparatus and methods of the invention will rely on detection of optical radiation in the infra-red radiation ranges. In particular, as noted above, ranges of 2-14 micrometers are of particular interest in the apparatus and methods of the invention. Referring to FIG. 2 , it can be seen that it is possible to plot curves for radiation (numbers of photons×1×10 17 ) being emitted by black bodies held at differing constant temperatures (T 1 , T 2 and T 3 each refer to temperatures in the range of 300-310° K. which vary from one another increasingly by 1° K.) in the wavelength range of 3 up to 6 micrometers. It can also be seen in the inset to FIG. 2 , that in the range of approximately 5.3 to 5.6 micrometers, black bodies held at constant temperatures in the range of 300-310° K. and differing from one another by only a single degree, appear as easily distinguishable curve segments, emitting photons from these black bodies in the range of approximately 0.21×10 17 to 0.40×10 17 photons. Thus, it is preferred to select a wavelength for sampling the radiation from the wall and specific locus on the wall of a vessel which will provide similarly distinguishable curves.
[0047] In certain preferred embodiments, the apparatus and methods of the invention may comprise at least two fibers, although the use of greater than two fibers is clearly possible where merited, such as when detection along the axis of the vessel is preferred at greater than a single position simultaneously. In other preferred embodiments, where at least two fibers are utilized, at least one of the fibers is a reference fiber and another of the fibers is a signal fiber. The signal fiber is a fiber designed to transmit all optical radiation focused into its length from its distal end to its proximal end. Conversely, the reference fiber is a fiber which is used as a control against which the signal fiber transmissions may be compared. Thus, where optical radiation exiting the proximal end of the signal fiber is compared to that exiting the proximal end of the reference fiber, a determination can be readily made as to relative amounts of optical radiation exiting the signal fiber which is due to other than optical radiation emitted by the locus of interest.
[0048] The apparatus of the invention may also be optically connected at the distal end of the signal fiber to an optically reflective surface capable of directing optical radiation arising radially to said distal end, and on into said fiber. U.S. patent application Ser. No. 08/434,477 in which certain of the present inventors are named co-inventors, and which is incorporated herein by reference, describes such an optically reflective surface. As opposed to the signal fiber, the reference fiber will typically be coated on its distal end with a material that substantially prevents optical radiation from entering it.
[0049] The apparatus of the invention is also one in which the inner surface of the opaque occluding balloon emits a black body spectrum modulated by the transmission spectrum of the balloon. The balloon, upon inflation, will substantially limit flow of fluids within the vessel. The flow limitation required is one in which only so much flow occurs as will not cause a rise or fall in average background IR radiation along the vessel wall immediately distal the inflated balloon. In addition, in preferred embodiments, the apparatus of the invention is one where the balloon, upon inflation, substantially excludes the presence of intervesicular fluids between the fibers inside the balloon and the wall of the vessel most proximate to the test locus.
[0050] In use, the apparatus of the invention will be placed along an axis of the vessel. in this manner, it will be possible to bring the diagnostic fiber array into close proximity with a locus to be diagnosed. In certain preferred embodiments, the locus will be one which contains plaque. In particular, the apparatus as previously noted will be useful in detecting among those plaques with which it is brought into proximity, whether a given plaque is one at risk of rupturing. In most instances, the apparatus of the invention will be used to diagnose thermal discrepancies on the interior wall of a vessel.
[0051] The apparatus of the invention is in its most preferred embodiments a catheter. Typical of catheters used inside of blood vessels, the catheter of the invention will be one designed for use with a guidewire. The guidewire will allow optional removal and reinsertion at the discretion of the surgeon, for example where after diagnosing a plaque at risk of rupturing using the catheter of the invention, the surgeon may wish to bring another diagnostic device or a therapeutic device such as a laser into the same position next to the problematic plaque.
[0052] The apparatus of the invention is also one where the detector is preferably optically connected to a proximal end of the fiber, and if there is more than one fiber, to a proximal end of each of the fibers. In preferred embodiments, the detector will be a multi-wavelength radiometer.
[0053] Such a radiometer will preferably be a spinning circular variable filter whose transmission wavelength is a function of its angle of rotation. In such a filter, it is possible to prevent transmission of all but a narrow band of wavelengths of light by adjusting the rotational angle. Said differently, such a filter can be made to be transparent to highly selected wavelengths by its rotational characteristics. Thus, in certain embodiments, the filter will be one transparent to radiation with a wavelength of approximately between 2 to 6 micrometers. In highly preferred embodiments, the filter will be transparent to radiation with a wavelength of approximately 3 micrometers.
[0054] One of the keys to this invention as it relates to the apparatus, is that it automatically provides a reference for each spectrum by sampling approximately 3 μm. For the range of temperatures expected in biological organisms, 300-310° K., the blackbody spectrum at this wavelength is essentially the same. This provides a zero for each signal and locks down the low wavelength side of the signal. Without this, there would be no way to fit a signal to a blackbody spectrum since the vertical scale would be “unfixed”.
[0055] Where the apparatus of the invention utilizes the transmitted information from more than one fiber through a filter for comparative purposes, it will be preferred to utilize an offset in the distal fiber ends. Thus, where the distal ends of the signal fiber and the reference fiber are offset from one another, the offset will be at a distance sufficient to allow sampling of radiation emitted from either fiber to pass the filter at a substantially identical location on the filter.
[0056] The apparatus of the invention when used in conjunction with a radiometer, will preferably be one optically connected to at least one photoelectric device capable of converting the transmitted radiation into an electrical signal. The photoelectric device is preferably one electrically connected to a device capable of digitizing the electrical signal (a digitizer).
[0057] Once the apparatus of the invention has created a digitized signal, the digitized signal is mathematically fitted to a curve selected from a spectrum of curves for black bodies held at temperatures between approximately 300-310° K. The curves of the controlled black bodies are those plotted as numbers of photons emitted from each black body for each wavelengths. In instances where such a digitized signal is to be used to diagnose thermal discrepancies in the interior wall of a blood vessel, the particular selection of black body control curves will be made with the knowledge of typical temperatures of the human body.
[0058] Thus, in a preferred embodiment, the apparatus of the invention will be a catheter for analyzing infra-red radiation of a blood vessel. Such a preferred device will comprise at least two fibers capable of transmitting the radiation and capable of placement along an axis of the vessel proximate to a plaque containing locus of an interior wall of the vessel. At least one of the fibers will be a reference fiber coated on its distal end with a material that substantially prevents optical radiation from entering it, and at least one of the other of the fibers will be a signal fiber whose distal end is optically connected to an optically reflective surface capable of directing optical radiation arising radially to its distal end into and along its shaft. Such a preferred device will also have a balloon encasing the distal ends of each of the fibers, which balloon upon inflation will substantially limit the flow of fluids within the blood vessel. In addition, the balloon will substantially exclude fluids between the fibers and the wall of the vessel most proximate to the locus to be tested. The balloon will be transparent to or opaque to the radiation arising inside the vessel and will have an inner surface exhibiting spatially constant optical radiation emissivity. This inner surface of the opaque balloon will be one which emits a black body spectrum. The catheter will be one having a guidewire. It will also have a detector, optically connected to a proximal end of each of the fibers, and capable of detecting a difference in the radiation between the locus and average optical radiation along the wall of the vessel. The detector will further comprise a multi-wavelength radiometer with a spinning circular variable filter, the filter being such that its transmission wavelength is a function of its angle of rotation. The distal ends of the fibers will be offset from one another a distance sufficient to allow sampling of radiation emitted from either fiber to pass the filter at a substantially identical position on the filter. Further, the radiometer will be optically connected to at least one photoelectric device capable of converting the transmitted and filtered radiation into an electrical signal, which signal is capable of being digitized, and which digitized signal is mathematically fitted to a curve selected from a spectrum of curves for black bodies held at temperatures between approximately 300-310° K., where the curves are plotted as numbers of photons emitted from each of the black bodies for each of the wavelengths.
[0059] The invention also relates to an analytical method, suitable in certain embodiments for diagnosing medical conditions. Thus, the invention relates to a method for analyzing optical radiation of a locus in a vessel wall. The method of the invention comprises placing at least one optical fiber capable of transmitting radiation proximate to the locus. In preferred embodiments, the placement of the fiber and balloon is accomplished by catheterization. Either prior to or after placement proximate to the locus to be analyzed a balloon encasing a distal end of the is fiber is inflated within the vessel to cause the balloon to limit flow of fluids within the vessel. As previously detailed, the balloon is transparent to or opaque to the thermal radiation and has an inner surface exhibiting spatially constant optical radiation emissivity. The methods of the invention further call for transmitting the radiation along the fiber to a detector capable of detecting a difference in the radiation between the locus and the average optical radiation along the vessel wall.
[0060] More specifically, the invention relates to a method of detecting plaque at risk of rupturing alone a blood vessel. This preferred method comprises inserting a guidewire into the blood vessel to be diagnosed and then catheterizing the vessel along the guidewire with at least two fibers capable of transmitting infra-red radiation along an axis of the vessel proximate to a plaque-containing locus of an interior wall of the vessel. Thereafter, the steps of the method of the invention is carried out as described above.
[0061] The invention also relates to a method of surgically treating a patient with a plurality of plaque loci within a vessel. Such a method comprises determining which one or more of the plurality of plaque loci has a temperature elevated above that of the average vessel wall temperature. Once such a determination is made, the surgeon removes or reduces the plaque loci found to have an elevated temperature. This method has as its determination step the methods described above for analyzing optical radiation of plaque locus in a vessel wall. Once plaque at risk is identified, a number of therapies may be used to reduce the risk.
[0062] Accordingly, it is an object of the present invention to identify patients who have coronary atherosclerotic plaque at risk of rupture by identifying the specific plaque(s) at risk. Another object of the present invention is to identify patients at risk for arterial restenosis after angioplasty or atherectomy by identifying the specific arterial site(s) at risk. A further object of the present invention is to identify patients at risk of transplant vasculopathy. Another object is to identify patients at risk for stroke, loss of mobility, and other illnesses by identifying sites of potential plaque rupture in the carotid arteries, the intracerebral arteries, the aorta, and the iliac and femoral arteries. Another object of the present invention is to identify patients who have arterial areas of lower rather than higher temperature, such as an area of extensive scarring, a lipid pool with no cellular infiltration, or an area of hemorrhage and thrombosis which has yet to be colonized by inflammatory cells. The delineation of a cholesterol pool is useful in following the regression of plaques. Identifying such areas for follow-up study will localize those likely to be inflamed in the future.
[0063] Yet another object of the present invention is to deliver specific local therapy to the injured areas identified by the catheter. These therapies include, but are not limited to, therapies which prevent or limit inflammation (recruitment, attachment, activation, and proliferation of inflammatory cells), smooth muscle cell proliferation, or endothelial cell infection, including antibodies, transforming growth factor-β (TGF-β), nitric oxide (NO), NO synthase, glucocorticoids, interferon gamma, and heparan and heparin sulfate proteoglycans, and the various complementary DNAs that encode them.
[0064] The invention's methods and devices will have a number of utilities. Bach will reduce morbidity and mortality from coronary and carotid artery atherosclerosis. Each will reduce the incidence of restenosis and thus the need for repeated angioplasties or atherectomies. Each will also reduce the incidence of vasculopathy in organ-transplant patients. In turn, these outcomes will produce the benefits of better health care, improved public health, and educed health care costs. These and other uses of the present invention will become clearer with the detailed description to follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0065] FIG. 1 is a schematic representation of the apparatus of the present invention with its infra-red detection unit at its proximal end and the sensor tipped distal end of the catheter as well as the guide wire disposed within a flexible outer catheter (not shown) which surrounds the optical fibers.
[0066] FIG. 2 is a black body curve spectrum for temperatures T 1 , T 2 , and T 3 (differing sequentially by a single degree Kelvin) plotted as emitted radiation in photons (x1E17) versus wavelength (micrometers).
[0067] FIG. 3 is a length-wise cross sectional view of the catheter tip of FIG. 1 in place within a blood vessel near a plaque at risk of rupture.
[0068] FIG. 4 ( a ) is a graph depicting surface temperature of living carotid artery plaque in relation to cell density. Relative cell density equals the ratio of cell density in the area of interest to that of the background area. Temperature measurements were made at room temperature (20° C.) on 24 samples from 22 patients 10-15 minutes after removal. Point (O° C. difference in temperature) represents 27 observations.
[0069] FIG. 4 ( b ) shows the correlation between living human carotid plaque temperature and cell density when measured in a 37° C. chamber.
[0070] FIG. 5 is a graph depicting plaque surface temperature as a function of cap thickness. Samples that had a non-inflamed fibrous cap were subjected to planimetry to measure distance from the lumen to the center of the underlying cell cluster.
[0071] FIG. 6 shows the correlation between thermistor and IR camera measurements in living human carotid plaque specimens (freshly excised, in a 37° C. chamber) where r=0.9885 and p=0.0001.
[0072] FIG. 7 shows the correlation of IR radiation with cell density in the specimens described in FIG. 6 , above.
DESCRIPTION OF PREFERRED EMBODIMENTS
The Catheter Embodiment
[0073] Referring now to the figures, FIG. 1 shows a preferred embodiment of the apparatus of the invention in use. A catheter apparatus 10 is shown, which can be placed inside an artery (not shown) having with an interior arterial wall (not shown) which possesses a plurality of plaque loci (not shown). The risk; of rupture of either of the plaque loci is unknown until the methods and apparatus of the invention are applied.
[0074] Guidewire 20 has been surgically inserted into the artery and can be seen to extend both proximally 22 and distally 24 . Guidewire 20 can also be seen to proceed through catheter apparatus 10 . Guidewire 20 is used to guide the placement of catheter apparatus 10 to the area of the artery which contains plaque loci.
[0075] Catheter apparatus 10 comprises at its distal end (the end farthest from the detector) an inflatable balloon 40 , a signal fiber 50 , and a reference fiber 60 . Inflatable balloon 40 is shown in its inflated state, which would cause it to rest firmly against an interior wall of an artery and against plaque loci. Depending upon the natural direction of blood flow within the artery, inflation of balloon 40 would substantially limit flow of blood either at position 32 or 34 or any of the similar points around the perimeter of the generally circular series of contact points between the balloon wall 42 and an interior artery wall, allowing measurements being conducted by catheter apparatus 10 to proceed without interference.
[0076] Balloon 40 comprises a wall 42 which is made of an elastic material. The perimeters of balloon 40 are such that inflation causes sealing or closure of the balloon 40 at points along the arterial wall. When deflated, balloon 40 retreats from its contact of the arterial wall, allowing reestablishment of natural blood flow within the artery, and allowing facile movement of catheter apparatus 10 in the artery to a next position, for instance to a position at which catheter apparatus 10 may be used to measure radiation emitted from another plaque locus. Activation of inflation/deflation of balloon 40 may be accomplished in any of a number of ways known well to those of skill in the art of building angioplasty or embolectomy catheters or balloon-tipped catheters.
[0077] The purpose of balloon 40 is to avoid problems associated with absorption of infra-red radiation by water between the source of infra-red radiation being measured and the distal catheter portion. Upon inflation and contact of the artery wall, the balloon wall 42 assumes the temperature of the portions of the artery with which it is most proximate. The void area 46 excludes all water between the balloon wall interior and the distal signal fiber tip 56 .
[0078] Signal fiber 50 has a translucent tip region 52 and an opaque body region 54 which is capable or incapable, respectively, of transmitting infra-red radiation efficiently. Opaque body region 54 may be a region in which signal fiber 50 is covered over by a cladding or sleeve 56 which causes the region to become opaque and incapable of efficiently transmitting or absorbing infra-red radiation. Translucent region 52 may simply be an area in which signal fiber 50 is exposed. Signal fiber 50 is an optical fiber which can efficiently transmit infra-red radiation. In order to collect such radiation from the surrounding milieu, signal fiber 50 may be fitted or otherwise used at its distal end with a collecting device 58 which focuses the infra-red radiation of the surrounding milieu into the fiber for subsequent transmission.
[0079] Unlike signal fiber 50 , reference fiber 60 has no translucent region. Rather, reference fiber 60 has an opaque end 62 and an opaque region 64 , both of which are incapable of transmitting infra-red radiation efficiently. As with the signal fiber 50 , reference fiber 60 , opaque region 64 may be a region in which reference fiber 60 is covered over by a cladding or sleeve 66 which causes the region to become opaque and incapable of efficiently transmitting or absorbing infra-red radiation. Opaque end 62 may be an area in which reference fiber 60 is coated with an infra-red reflective coating such as polished silver or aluminum. In all other regards, reference fiber 60 is identical to signal fiber 50 in its ability to function as an optical fiber which can efficiently transmit infra-red radiation. It may be used, therefore, to set a baseline in order to compensate for any temperature profile along signal fiber 50 from its distal to its proximal end. As shown in FIG. 1 , reference fiber 60 is offset from signal fiber 50 in the proximal direction. This offset (which can be equally well accomplished by offsetting distally) physically introduces a time delay between the radiation received and transmitted by each fiber. As will be discussed immediately below, this time delay is introduced in order to ensure that the signal and reference beams issuing from the proximal ends of each fiber strike the filter on the same spatial portion. By doing so,it is possible to eliminate alignment problems or bandpass dissimilarites arising from a multi-filter system.
[0080] When in operation, the fiber-balloon array 70 collects thermal radiation which is transmitted proximally through signal fiber 50 and reference fiber 60 . Both fibers are positioned to transmit through spinning radiometer 80 at identical radial position 82 to impinge on digitizers 92 or 90 , respectively. Once a digitized signal is generated from each of the optical fiber transmissions, the background signal created by the reference fiber 60 is subtracted by computer 94 from the digitized signal transmitted by the signal fiber 50 . The resulting adjusted signal is mathematically fitted by computer 94 to a spectrum of black body curves 96 in order to ascertain the temperature of the particular locus.
[0000] Catheter Construction
[0081] Several options for materials for the other various components of the catheter devices described herein exist The key parameters for the optical components are optical transparency, flexibility and strength. Materials such as high strength polyester and polyethylene terephthalate (PEI) are very clear and easily extruded in ultrathin wall sizes. A high strength braided polyester is useful for translating twisting motions over long distances as may be required in certain embodiments. Spacers/bearings can be made from Teflon®. The overall flexibility of the catheter will be approximately the same as similar-sized cardiovascular laser, fiberoptic, angioplasty and atherectomizing catheters. These devices should therefore be deliverable to small diameter coronary arteries. A detector will be positioned at the proximal end of the catheter (outside the patient) utilizing InSb or, alternatively, HgCdTe, TeO 2 or TAS detection systems.
[0082] The elongated flexible fiberoptic element will be connected at one end to an optical connector through a protective sheath. The optical connector is a standard item adapted to be slidably inserted into a thermal detector, and will include a plurality of openings in one side through which fluids or gases, including air, can be-introduced into the catheter and emitted therefrom. The connector will also include a coupling element for connecting to a pressure transducer to measure pressure, there being an opening in the connector communicating with the coupling element and the pressure lumen of the catheter. The coupling element may also be connected to a syringe to take a blood sample or to use a saline solution to flush the catheter.
[0083] The materials of which catheters are constructed may be any of those commonly used, including flexible plastics such as nylon, Teflon™, vinyls such as polyvinyl chloride, polyurethane, and polyethylene, or various rubber compounds. Typically, the catheter will typically be 5 to 40 inches long and have an outer diameter of about 1 to 2 millimeters. The lumen inside the catheter can vary but typically will be about one half to 1 millimeter in diameter.
[0084] The minimum detectible heat differential using the devices and materials of the present invention will be about 0.1° C. While the devices of the invention will be capable of finer thermal discrimination, biological variables are apt to introduce noise into the system. In most instances, plaques which are in danger of rupturing will vary from those less at risk by at least 1.5° C.
[0000] At-Risk Plaque
[0085] Generally then, as an overview of the device and method of the invention in FIG. 3 , the infrared-sensing catheter 100 has identified an ulcerated atherosclerotic plaque 102 which is accompanied by platelet aggregation 103 and vasoconstriction 104 Because of the presence of inflammatory cells 105 in this plaque 102 , its temperature is higher than that of the immediately adjacent vessel 107 , and this change is sensed by the catheter 100 . Some endothelial cells 108 have been lost (as a result of senescence, inflammation, infarction, toxins, or balloon injury) causing platelets 109 to become activated and to adhere to the imaged vessel wall 110 . The activated platelets 109 release mediators that cause vasoconstriction, platelet aggregation, and growth of smooth muscle cells; these mediators include ADP, serotonin, thromboxane A 2 , platelet-derived growth factor, transforming growth factor-β, and PF4. The exposure of subendothelial collagen 111 and lipid 112 and the activation of platelets promote enzymatic activation of coagulation enzymes, which result in the release of plasma mitogens and the activation of thrombin, an enzyme which cleaves fibrinogen to form fibrin. The culmination of this process may be complete occlusion of the artery and consequent injury to the heart (or brain, in the case of a carotid, vertebral or cerebral artery).
[0086] Also shown is a monocyte 114 , which has attached itself to adhesion molecules on the surface of activated endothelial cells. The monocyte becomes a macrophage involved in uptake of modified cholesterol and the release, as by-products, of mitogens and proteolytic enzymes that may promote rupture.
EXAMPLE I
[0000] Methods
[0087] Fifty carotid endarterectomy specimens were studied in the living state after gross inspection by a pathologist. Visible thrombi, noted in about 30% of the specimens, were typically removed by gentle irrigation, suggesting that they were surgical artifacts. The indications for surgery were generally a carotid stenosis and transient ischemic attack or stroke.
[0088] Twenty-four specimens from 22 patients were examined at room temperature (20° C.). Another 26 specimens from 26 patients were examined in a humidified incubator at 37° C.
[0089] Within 15 minutes after removal of a specimen, a Cole-Parmer model 8402-20 thermistor with a 24-gauge needle tip (accuracy, 0.1° C.: time constant, 0.15) was used to measure the temperature of tile luminal surface in 20 locations. Temperatures were reproducible (+0.1° C.), and most measurements were found to be within 0.2° C. of each other and thus were designated as the background temperature.
[0090] In most plaques, several locations with higher temperature were all found. These locations and the background temperatures were marked with indelible ink of varying colors (recorded, but not coded so as to indicate the temperature to the pathologist) and re-measured to assure reproducibility. Tissues were then fixed in 10% formalin and cut lengthwise, embedded to reveal the intima and media, processed for histology, and stained with hematoxylin and eosin or Masson's trichrome, or immunostained for macrophages using the HAM-56 and KP-1 antibodies (Dako) as previously described. Nikiri, et al, Circulation 92:1393-1398 (1995). The cap thickness and the cell density in a 300×400-μm region beneath the dyed regions was measured using a Mackintosh Centris 650 and NIH Image software (version 1.43), available on the Internet from the National Institutes of Health, Bethesda, Md.
[0091] Preliminary experiments were also performed with a Jet Propulsion Laboratory platinum silicide camera, which we further calibrated against a Mach 5 scanning infrared camera (Flexitherm, Westbury, N.Y.),—which in turn was calibrated against beakers of water at various temperatures from 0 to 100° C. with a near perfect correlation, y=0.99x+0.31, where x was the temperature measured by mercury thermometer. The camera had a thermal resolution of 0.10° C. and a spatial resolution of 0.15 mm.
[0000] Results
[0092] Plaques exhibited multiple regions in which surface temperatures varied reproducibly by 0.2 to 0.3° C. (±1.0° C.), and 37% of the plaques had 1 to 5 substantially warmer (0.4 to 2.2° C.) regions per plaque. For instance, in typical instances, regions 1 mm apart had a reproducible temperature difference of 0.6° C. Although the lumenal surfaces of the plaques exhibited visible heterogeneity, differences in temperature were not apparent to the naked eye. These temperature differences correlated positively with the underlying density of cells (r=0.68, p=0.0001) ( FIG. 4A ), most of which were mononuclear cells with the morphologic characteristics and immunoreactivity (with HAM-56 and KP-1) of macrophages.
[0093] Several mitotic figures were noted. Some foam cells were noted, but regions predominantly populated by foam cells were cooler (and had lower cell density) than regions with mononuclear infiltrates. Many plaques contained a few lymphocytes and mast cells.
[0094] Temperature varied inversely with cap thickness (r=−0.38, p=0.0006) ( FIG. 5 ). The best correlation (r=0.74, p=0.009) was given by the theoretically expected equation ΔT=relative cell density÷cap thickness. Cooler regions were nonellular: fresh thromboses, hemorrhage, scar, calcium, or regions of cholesterol pooling without inflammatory infiltration.
[0095] The warmer regions were not visibly different on gross inspection, even though many of them had a superficial layer of inflammatory cells, some of which had small aggregations of platelets. Other large areas were free of inflammatory cells but lacked endothelial cells. These had probably been denuded during surgery, since postmortem studies usually show only focal denudation unless there is thrombosis or inflammation. Van Damme, et al., Cardiovasc Pathol 3:9-17 (1994).
[0096] A minority of plaques (approximately 20%) exhibited no detectable thermal heterogeneity. Regions of deep or superficial inflammation in these specimens were not marked with dye, indicating that the overlying temperature had not been measured. In a few of the regions containing cellular infiltrates, temperatures had been measured, and they were no warmer than less cellular adjacent areas. This finding was believed by the inventors to possibly defect decayed metabolic activity in specimens that were kept at room temperature for a longer interval after removal.
[0097] Therefore, a second series of plaques was analyzed in a 37° C. incubator. These 26 specimens from 26 patients with a mean age of 68 (range, 50 to 86) revealed a considerably closer correlation with cell density (r=0.68, p<0.0001), more thermal heterogeneity (93% of specimens), and a wider range of temperatures, typically 1 to 3° C.; some specimens only 10 mm apart were characterized by temperature differences as great as 4 to 5° C. See, FIG. 4B (points represented by solid diamonds are the relative cell densities divided by the cap thickness squared; linear regression of these points resulted in the solid line shown).
[0098] The inventors also studied several specimens using a platinum silicide, cooled, infrared camera with a thermal resolution of 0.1° C. and a spatial resolution of 0.1 mm. This camera detected thermal heterogeneity in ex vivo specimens. As shown in FIG. 6 , the IR camera when used to identify thermally distinct plaque correlated well with direct contact thermistor measurements in freshly excised human carotid artery plaques specimens (r=0.9885, p<0.0001). FIG. 7 shows that this correlation of the IR camera measured temperatures was also observed with cell density measurements. It is noted by the inventors that cooled staring array cameoas have even better thermal resolution, and spatial resolutions are as low as 10 μm.
[0000] Conclusions
[0099] Most human carotid atherectomy specimens contain foci of increased heat apparently produced by underlying cells, most of which are macrophages. When studied at 37° C., the temperature variation was greater than 20° C., consistent with reduced metabolic activity at 20° C. that makes the plaques more homogeneous in temperature.
[0100] In the samples studied at body temperature, a thermistor with a 1-mm tip was able to detect differences as great as 4° C. within different parts of the same plaque that were only 10 mm apart. Temperatures were highest when the cells were closest to the probe (i.e., at or just beneath the lumen itself). Most of the lumenal surfaces of the plaques had several regions characterized by superficial inflammation and endothelial denudation.
[0101] Only some areas of surface inflammation were associated with visible thrombosis; most were associated with microscopic thrombosis (e.g., a few fibrin strands and attached platelets) or nonlall. These results suggest that increased plaque heat is an indicator of plaques that are denuded and inflamed and consequently at risk of thrombosis.
[0102] The inventors also found a few hot regions associated with foci of inflammation just beneath thin but intact caps. Since these plaques are believed to be at increased risk of rupture, it is believed by the inventors that measuring plaque temperature in vivo could enable one to identify such plaques.
EXAMPLE II
[0000] Limitations of the Study
[0103] A potential confounder identified by the inventors is plaque angiogenesis (neovascularization). The inventors studied living plaques ex vivo. In vivo, the presence and tone of the vasae vasorum might influence the temperature. However, since plaque angiogenesis coreuates with inflammation, (Nikkari, et al., Circulation 92:1393-1398 (1995) and both are considered risk factors for plaque rupture, it is likely that temperature will still be predictive in vivo.
[0104] The inventors also believe that one must consider that what is true for atherosclerotic plaque in the carotid arteries may not be true in other sites, for example, the coronary arteries. The pathology of the plaque is somewhat different in the two locations. (Van Damme, et al., Cardiovasc Pathol 3:9-17 (1994)) and the risk factors are also different. Kannel, J Cardiovasc Risk 1:333-339 (1994); Sharrett, et al., Arterioscler Thromb 14:1098-1104 (1994).
EXAMPLE III
[0000] Potential of Spectroscopy, Tomography, and Interferometry
[0105] Infrared spectroscopy could prove useful in several ways. First, it should be able to corroborate the location of macrophages by the massive amounts of nitric oxide they produce, since nitric oxide has a characteristic near-infrared spectrum. Ohdan, et al., Transplantation 57:1674-1677 (1994). Near-infrared imaging of cholesterol has already been demonstrated. Cassis, et al., Anal Chem 65:1247-1256 (1993). Second, since infrared and near-infrared wavelengths penetrate tissue more deeply as wavelength increases, longer wavelengths should reveal metabolic activity in deeper (0.1- to 1-mm) regions.
[0106] This phenomenon could be used to develop computed infrared tomography, possibly in conjunction with interferometry, in which an incident began is split by a moving mirror to produce a reference beam and a beam that is variably scattered and absorbed by the tissue. The nonsynchronous reflected wavelengths are reconstituted to reveal structural detail with 20-μm resolution. Benaron, et al., Science 259:1463-1466 (1993); Brezinski, et al., Circulation 92: 1-149 (1995).
EXAMPLE IV
[0000] Noninvasive Detection of Plaques at Risk
[0107] Alternatives to infrared detection are also desirable since infrared absorption, convection, and tissue emissivity differences are likely to preclude non-invasive infrared tomography. Such alternatives include imaging the inflammatory cells with gallium, (Pasterkamp, et al., Circulation 91:1444-1449 (1995)) 18 FDG positron scanning, radiolabeled anti-macrophage antibody fragments, or magnetic resonance (to take advantage of the temperature-dependence of proton-spin relaxation). MacFall, et al., Int J Hyperthermia 11:73-86 (1995).
[0108] These techniques lack sufficient spatial resolution for detecting inflammatory foci bent the surface of moving coronary arteries (particularly circumflex and distal vessels) and cannot be used ‘on line’ to direct plaque-specific interventional therapies. However, the resolution in these techniques may be adequate in thick-walled, relatively stationary arteries such as the aorta, carotid and femoral arteries. Toussaint, et al., Arteriocler Thromb Vas Biol 15:1533-1542 (1995); Skinner, et al., Nature Medicine 1:69 (1995). If lumenal inflammation can be distinguished from adventitial inflammation, the latter may prove useful in predicting progression of aortic aneurysms.
EXAMPLE V
[0000] Therapeutic Implications
[0109] Lowering serum cholesterol concentrations by means of diet or drugs can reduce mortality, perhaps because reverse cholesterol transport reduces the size of the lipid core. However, the most convincing trial to date indicates only a 35% decrease in coronary mortality with cholesterol-lowering therapy (and little benefit in women). Scandinavian Simvastatin Survival Study Group, Lancet 344:1383-1389 (1994). This finding suggests that other factors, such as hemostatic variables, are affecting mortality. However, even with the same patient, plaques progress or regress relatively independently. Gould, Circulation 90:1558-1571 (1994). This variability suggests that lesion-specific variables (for example, stenosis length, surface thrombosis, low shear stress due to low or turbulent flow, and vasoconstriction) increase the risk of thrombosis. Alderman, et al., J Am Coll Cardiol 22:1141-1154 (1993); Nobuyoshi, et la., J Am Coll Cardiol 18:904-910 (1991).
[0110] If hot plaques producing stenoses in the “non-critical’” range of 10% to 70% are shown to be at high risk of rupture, should they undergo angioplasty? If the risk of dilation is similar to that of more severe stenoses (approximately 1% mortality, 2% aortocoronary bypass), what is the benefit of converting an unstable lesion into one with a 70% chance of long-term patency and a 30% chance of restenosis? Even before the recent trials indicating that stents reduce restenosis rates to 10% to 20%, the large Emory follow-up indicated an identical 96% five-year urvival rate in patients with and without restenosis, despite the increased need for repeat ngioplasty or bypass surgery in the former group. These data suggest that angioplasty could be beneficial if the near-term risk of sudden (spontaneous) occlusion is only about 5%.
EXAMPLE VI
[0000] Medical Therapies
[0111] Medical therapies would depend, in part, on whether the inflammation is on the surface or beneath an intact cap. This distinction may one day be made by angioscopy (especially with the use of light-emitting antibodies) or by sampling blood for soluble markers of inflammation (P-selectin, VCAM-1, and others). Magnetic resonance imaging, ultrasound, and near-infrared imaging may also prove helpful.
[0112] Therapies might include local delivery of agents (peptides, peptide mimetics, oligonucieotides, and others) that prevent monocyte recruitment, attachment, activation, or DNA synthesis. Conversely, Collagen synthesis might be stimulated with ascorbic acid or transforming growth factor β (which also acts to inhibit angiogenesis, inflammation, and smooth muscle proliferation in most models, though it can also provoke inflammation in non-inflamed tissue and delay endothelial regeneration). Nathan, et al., J Cell Bol 113:991-986 (1991). Endothelial regeneration can be enhanced by basic or acidic fibroblast growth factor or by vascular endothelial growth factor, among others. Casscells, Circulation 91:2699-2702 (1995).
[0113] In summary, living human carotid atherosclerotic plaques exhibit thermal micro-heterogeneity attributable mainly to macrophages at or near the lumen. These regions of increased temperature can be identified by thermistors and infrared thermography. If hot plaques are indeed at high risk of thrombosis (or restenosis (Gertz, et al., Circulation 92:1-293 (1995); Moreno, et al., Circulation 92:1-161 (1995)) or—in the case of adventitial inflammation—of aneurysmal rupture, it may be possible to develop catheter-based and noninvasive means of imaging and treating these potentially life-threatening lesions. These technologies might also be used to detect subepithelial clusters of inflammatory or malignant cells in other organs by magnetic resonance imaging or by endoseopy, ophthalmoscopy, laparoscopy, artheroscopy, or transcranial imaging.
[0114] The present invention has been described in terms of particular embodiments found or proposed to comprise preferred modes for the practice of the invention. It will be appreciated by those of skill in the art that, in light of the present disclosure, numerous modifications and changes can be made in the particular embodiments exemplified without departing from the intended scope of the invention. For example, while the present invention has been supported by examples in the biomedical arts, the apparatus and methods of the invention may be equally well applied to the analysis of wall weaknesses of any vessel so long as such weaknesses exhibit or can be made to exhibit differential heating. Thus, manmade vessels such as conduit, if heated externally may be subjected to internal analysis using the apparatus and methods of the invention. All such modifications are intended to be included within the scope of the appended claims.
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An infrared, heat-sensing catheter particularly useful for identifying potentially fatal arterial plaques in patients with disease of the coronary or other arteries and its use are detailed. In one embodiment, an infrared fiberoptic system (with or without ultrasound) is employed at the tip of the catheter to locate inflamed, heat-producing, atherosclerotic plaque, which is at greater risk for rupture, fissure, or ulceration, and consequent thrombosis and occlusion of the artery. In another embodiment, a catheter with an infrared detector (with or without ultrasound) employed at its tip will likewise locate inflamed heat-producing atherosclerotic plaque. The devices and methods of the invention may be used to detect abscesses, infection, and cancerous regions by the heat such regions differentially display over the ambient temperature of immediately adjacent tissues. The methods and devices of the invention may also be used to detect regions of cooler than ambient tissue in a vessel or organ which indicate cell death, thrombosis, cell death, hemorrhage, calcium or cholesterol accumulations, or foreign materials.
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TECHNICAL FIELD OF THE INVENTION
The present invention relates in general to scented articles, and more particularly to wearing apparel with scented designs.
BACKGROUND OF THE INVENTION
The merchandising of wearing apparel is a significant industry and represents millions of dollars for businesses and billions of dollars for the national economy. While clothes in general provide the basic function of covering one's body and providing an insulation from the environment, the sales of clothes involves much more than the appeal to these basic interests. Brand names, style, design and other considerations are factors that are brought into focus in the marketing and merchandising of wearing apparel. Many designers highlight their clothing lines with logos, colors, designs and other insignia to distinguish their wearing apparel from that of competitors. Jeans have designer logos on the hind pockets, sports shirts bear the logos of the makers on the sleeves or pockets, socks have stitched insignia, t-shirts have numerous designs imprinted thereon, and other clothing items bear many different types of insignia to identify the makers thereof.
The sales of t-shirts and sweat shirts is an enormous industry, especially when coupled with an entertainment event. While the cost of the raw materials of a t-shirt may be under a dollar, or so, the price of a t-shirt embossed with a design and sold at an event may cost upwardly of $20. The designs applied to a t-shirt are limited only by the imagination of the designer. Multi-color designs are common, as are catchy slogans and the like. The competitiveness of such an industry is readily apparent at sports events, such as auto racing, football, basketball, baseball, etc. Other entertainment events such as rock concerts, festivals, social gatherings, etc., also provide respective forums for the marketing of such type of wearing apparel.
The process of placing a design on at-shirt, sweat shirt or other wearing apparel includes many considerations, the least of which is the selection of an ink which will endure a reasonable number of washing and drying cycles. In order to mass produce wearing apparel with designs applied thereto, a process must be used which allows multiple colors to be applied to the garment, and allowed to set or dry in a short period of time. Carousel equipment is readily available for printing complicated multicolor designs on t-shirts, at a rate of 800 t-shirts or more an hour. The design of the insignia is facilitated by the availability of computer equipment which allows a design to be easily copied or generated and transferred to a stencil, silk screen or other ink application equipment.
The t-shirt embossing industry constantly strives for an advantage over the respective competitors. New inks and processes continue to be developed to achieve better and more brilliant colors, more realistic designs with intricate shapes and definition. Inks are presently available for providing garment designs with a better “hand”. The “hand” of the design refers to the softness of the ink after a number of layers or colors have been applied to the material. Typically, various inks and/or layer of ink applied to a material makes the garment material somewhat stiff, resulting in a negative hand. Hence, by using more colors in a design, the the appearance is enhanced, but the softness of the finished product is often compromised.
While the development of new apparel designs continues to make the articles more aesthetically appealing, there is generally a lack of development of the incorporation of scented designs into wearing apparel. Again, any scented design involving an ink must be able to withstand a reasonable number of conventional washing and drying cycles, be non-allergenic and cost effective.
Inks typically used in printing text on paper are of the extract type, or are “essential” oil type scents. These scents generally do not have the longevity as compared to synthetic scents.
From the foregoing, it can be seen that there is a need for a new scented ink and application process for applying the same to an article. Another need exists for a scented design that can be applied easily and economically to wearing apparel. Yet another need exists for a process for applying a scent or fragrance to a design, which matches or is associated with the design.
SUMMARY OF THE INVENTION
The present invention disclosed and claimed herein, in one aspect thereof, comprises a scented ink that is applied to wearing apparel, such as a t-shirt. An oil-based scent, such as the type used for making scented candles, is mixed with a plastisol-type ink and applied to the wearing apparel using conventional screen print techniques. With this type of scent, the application of heat or warmth to the wearing apparel releases the scent. The scent used can match the design applied to the garment. For example, a grape scent can used with purple-colored ink to make a clustered grape design on the garment.
In accordance with another feature of the invention, layers of ink are employed to make the design, with each layer being scented. This process provides a longer lasting scent to the design when applied to an article. A first application of scented ink can be used a base layer for dark or light-colored material to provide a neutral color for applications of other colors thereon. Subsequent applications of scented inks, which may be different colored shapes and designs can be applied over the base layer. In a preferred form of the invention, each layer of a design would have the same scent. Lastly, an application of a clear scented ink can be used as a top coating to provide a shiny surface to all or selected portions of the design. By using a plastisol-type of ink, the colored and scented design has a high quality positive “hand”, i.e., a rubbery and soft texture to the feel.
According to other features of the invention, different thicknesses of stencils can be used on screens to provide different thicknesses of scented ink on the materials, thereby providing a larger source of the scent and allowing the scent to last a longer period of time.
DESCRIPTION OF THE DRAWINGS
Further features and advantages will become apparent from the following and more particular description of the preferred and other embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters generally refer to the same parts, elements or functions throughout the views, and in which:
FIG. 1 illustrates a flow chart of the steps carried out in making a scented design according to a preferred embodiment;
FIG. 2 illustrates the various layers or applications of scented ink in making a design; and
FIG. 3 illustrates the use of different thicknesses of scented ink for a design.
DETAILED DESCRIPTION OF THE INVENTION
While the invention is described below in connection within the application of a scented design on a garment, the principles and concepts of the invention can be applied as well to other mediums, such as panels, metals, upholstery, personal items and many other articles susceptible for accepting a design. As used herein, a “design” may include any insignia, slogan, word, symbol, etc.
In the preferred form of the invention, a scented design is applied to a t-shirt, such as the type sold at an event. For example, t-shirts are a popular item sold at regular season football and bowl games. A t-shirt sold, for example, at the Orange Bowl, can have imprinted thereon a design of one or more oranges with an orange scent. The Citrus Bowl is an opportunity for selling t-shirts with a citrus fruit design and a citrus scent. Many other applications are possible, such as, a smoke/tire burning scent for t-shirts sold at an auto racing event, a marijuana smell on t-shirts sold at a rock concert, a food scent on t-shirts sold at restaurants and food festivals, etc. Popular perfume scents can also be used in connection with screen print inks applied to sweaters and blouses for women. For outdoor activities and events, an insect repellent can be mixed with the ink and applied to the t-shirt, sweat shirt, or other apparel to prevent the annoyance of insects.
There are a number of scents that are presently considered to have beneficial medicinal effects. Such scents can also be applied to articles so that persons in the vicinity thereof can smell the scents and receive the benefits thereof. These scents, many of which are essential oils, include Italian bergamot, Brazilian bois de rose, Moroccan chamomile, cinnamon, Russian clary sage, Spanish eucalyptus, Russian fir needle, frankincense, Florida grapefruit, French lavender, California lemon, West Indian lime, Italian mandarin orange, Spanish marjoram, Musk, Indonesian patchouly, American peppermint, Canadian pine needle, rose, Spanish rosemary, Brazilian tangerine, Australian tea tree, Spanish thyme and Ylang ylang, etc.
While not considered to be exhaustive, the list of other scents that can be employed in connection with screen printing on articles, include the scents of plants, trees, flowers, shrubs, fruits, spices, vegetables, kitchens, the outdoors, animals, farms, factories, the sea, air, machinery, medicinal scents, wood, chemicals, petroleum products, etc.
Reference is now made to FIG. 1 of the drawings where there is shown a flow chart of the basic operations 10 in providing a scented garment. It has been found that a composition of a scented ink includes a plastisol-type screen print ink and an oil-based scent, much like the type used in making scented candles. With this type of scent, heat imparted to the scented design releases the scent from the ink. Hence, every time the garment is washed and dried, the scent from within the plastisol ink is moved to the surface of the ink and released. Depending on the amount of heat needed to release the scent, a garment made according to the invention may be heated sufficiently by the environmental heat of the sun to reactivated the scent. Candle-type scents and plastisol inks are readily available to those skilled in the art and need not be specially manufactured. It should be understood that scents other than those used in candle making can be used with the invention. In addition, those skilled in the art may choose to use other types of scents and inks without departing from the present invention.
In block 12 of FIG. 1, the steps are identified for mixing the scented oil and the ink. Here, two grams of a liquid oil-based scent is mixed with about 300 grams of a plastisol ink of the color desired. Different colored plastisol inks are available in gallons, or other volumes. Preferably, the scented oil is of a concentration of about 6.8%, namely about 6.8 parts (per unit weight) of the scent, and about 93.2 parts (per unit weight) of a petroleum-based carrier. Generally, the same amount of scented oil is used with a given amount of the plastisol ink, irrespective of the type of scent. As will be described below, plastisol is selected because it has a characteristic of a positive hand when applied in thick layers, or with plural thin layers. Other inks tend to have a negative hand when applied in layers, the result of which is that the material becomes stiff to the feel.
As noted in block 14 , a container of plastisol ink, which will form the base layer of the design, is also mixed with the scented oil. A container of a special effects clear plastisol ink is similarly mixed with the scented oil. As can be appreciated, the same amounts noted above are mixed together, and the same scent is generally employed in the colored plastisol inks, the base layer plastisol ink and the special effects clear plastisol ink. The base layer plastisol ink is generally a white ink for covering the entire area of the material to be covered by the design. The white plastisol ink tends to visually isolate the color of the garment material from the colored inks applied thereon. In accordance with the invention, the base layer of the plastisol ink, with the scented oil therein, is applied to every garment, irrespective of the color of the garment. With this arrangement, the base layer of the white plastisol ink functions as an additional source of the scent, thereby increasing the longevity of the scent of the design. Indeed, in order to further increase the amount of scent imbedded in the design, several layers of the base ink can be used. Since the ink is chosen in the preferred form of the invention to be a plastisol ink, the hand of the design remains positive, as compared to that which would be achieved with other conventional screen print inks. The same mechanism for increasing the mass or volume of the scented ink can be used by employing multiple or thick layers of the special effects scented ink.
In any event, each color of the plastisol ink is mixed in a container and allowed to set for a period of time in a closed container. While not critical, the mixture is allowed to set for about 48 hours. This time period allows the fragrance to permeate the ink and to become a homogenous mixture. This process step is shown in block 16 .
Once the mixed containers of the scented plastisol ink have aged for a period of time, the containers are opened and loaded into the respective reservoirs of the stations of a screen print carousel. With such type of automated mechanism, each station is fitted with a mesh screen having a specific stencil design. The stenciled screen is coupled to the particular reservoir of colored and scented screen print ink. This is shown in block 18 . At each station there is an ink applying mechanism to force the colored/scented ink through the stenciled screen onto the underlying garment. In order to transfer the ink design to a number of garments, the dwell time for the garment at each station of the carousel is about two seconds.
In step 18 of the process, the various stenciled screens are also loaded into the respective stations. It is noted that generally, each color of a multi-color design is associated with a different stencil because the shape of each color area of a design is different. If the sequence of the colors applied to the garment is important, then the colors are loaded in the proper sequence. Since the base color is applied first in the preferred embodiment of the invention, the white base color (or other base color coat) is loaded in the first station of the caroused to be applied first. In like manner, the special effects clear is the last color to be applied over all the other colors, and thus the clear coat ink is loaded in the last station of the carousel. In the event that it is desired to flash cure one color during the printing process, then a high temperature dryer can be installed in a station that comes after the color to be flash cured. The high speed curing of a color may be desired to prevent color bleeding between two adjacent colors.
In block 20 of the process flow, the screen printing process begins by loading the garments, either manually or automatically, onto the garment carriers of the carousel equipment. As the carousel garment carriers rotate and move into a position adjacent a print screen, the carriers stop for about two seconds to be printed with the color of the scented ink loaded into the station. The scented colors are sequentially applied to each garment in the manner noted. As shown in block 22 , if the scented color of a station requires a flash cure, then a carousel station is not fitted with color printing apparatus, but rather is fitted with a heater that provides heated air at a temperature of about 1100 degrees Fahrenheit. Many types of screen printing carousels are designed so that each station can be fitted with color printing apparatus, heaters, etc., all that are interchangeable when needed.
The last ink coating applied to the color design is a special effects clear, as shown in block 24 . This ink coating covers all the other colors previously applied, and creates a shiny surface that is aesthetically pleasing. The special effects clear coating is also a plastisol ink that is scented with the same scent as used in the other colors of the design.
With regard to block 26 , after the special effects clear has been applied to the design, the garments are routed to an in-line furnace or dryer where a temperature of about 325 degrees Fahrenheit is maintained. The garments pass through the dryer on a wire conveyor and are maintained at such temperature for about 45 seconds. Once the ink printed on the garments has cured, the garments are gathered, either manually or automatically, and packaged for shipment. This is shown in block 28 .
FIG. 3 is a cross-sectional view of a screen printed design 30 made according to one embodiment of the invention. Here, there is shown a fabric 32 as the material on which the design is printed. As noted above, the material is not limited to fabrics, but may be any material susceptible for receiving thereon a screen printed design. The base layer 34 of scented ink is screen printed over the entire area that is to receive the design. A first color 36 of the design is printed on the base layer 34 . Next, a second color 38 is screen printed on the base layer 34 . The first and second colors 36 and 38 need not be screen printed adjacent to each other. A third color 40 is screen printed on the base layer 34 . Lastly, the special effects clear layer 42 is screen printed over the entire area of the design. In certain cases, the special effects clear coating may be applied over only a selected portion of the design. Importantly, all the color layers 36 - 40 , as well as the base layer 34 and the special effects layer 42 are scented with the same scent. This increases the reservoir of the scent and provides a longer lasting fragrance.
From the foregoing, it is noted that in the preferred embodiment of the invention, the same scent is used for all the screen print inks used in a design. This is not a necessity, as it is possible to produce a design with two or more different scents. For example, the design of a cluster of oranges and leaves may be made with a orange ink scented with an orange scent, and with a green ink scented as leaves for the green part of the design. Moreover, if it is desired to make the leaf scent less prominent, then only the green ink or the special effects ink covering the leaves need be scented. Alternatively, the concentration of the leaf scent in the green ink can be less, as compared to the concentration of the orange scent in the orange ink. For a prominent orange scent, all ink layers above and below the orange design would be scented with an orange scent. With this arrangement, the special effects ink forming the top ink layer would be applied at different screen print stations, one with the orange scented special effects ink, and the other station loaded with a leaf scented special effects ink. It can be seen that different combinations of colors, scents and amounts of scent are possible according to the principles of the invention.
FIG. 3 illustrates another embodiment 50 of the invention for increasing the amount of scent held by an ink design. In this design 50 , one area 52 of the design 50 is made with a thicker layer of scented ink. This can be accomplished by using a thicker stencil, thereby allowing a thicker layer of ink to be deposited on the base material 34 . By using a thicker portion of the design, a three dimensional or textured effect can also be created.
Although the preferred and other embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention, as defined by the appended claims.
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A process in which a scented ink is applied to an article. An oil-based scent is mixed with a plastisol-type ink and applied to an article, such as a t-shirt. All layers of the ink forming the design, including the base layer, the color layers and a top special effects clear plastisol ink, include the scent. The combination of a plastisol ink and the oil-based scent results in a design with a positive “hand”, where elevated temperatures activate the scent.
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FIELD OF THE INVENTION
This application claims priority from PCT/US96/05270 filed Apr. 16, 1996 and from Israel patent application IL 113394 filed Apr. 17, 1995.
The present invention relates to nematicidal bacterial strains, and particularly to strains which affect plant-pathogenic nematodes. The invention also relates to agricultural nematicidal compositions as well as to methods of controlling plant pathogenic nematodes.
BACKGROUND OF THE INVENTION
Root-knot is one of the most serious plant diseases in the world. Throughout the world, root-knot disease causes an average annual yield loss of about 5%. The greatest losses however, occur to those who can least afford it, namely, the farmers of underdeveloped countries. Their losses may be as much as 25-50% over a wide area of available farmland. In addition, there are several indirect losses associated with root-knot disease including secondary attack by other pathogens (in combination with other pathogens, root-knot disease can be disastrous); inefficient utilization of fertilizer and water; and high cost of chemical treatment.
The most common parasites causing this disease belong to the Meloidogyne spp. These nematodes have been shown to parasitize more than 3000 plant species including all the main crop families. Root-knot nematodes are found in all climate zones and in most types of soil. They are more active in finding and attacking plants in warm climates than in colder regions. Plants infected by root-knot nematodes display one or both of the following symptoms: root systems are galled, shortened or reduced by rotting; the stems are shortened and thickened, and the leaves do not grow normally.
The most distinctive symptom caused by root-knot nematodes are the galls or knots on the roots. The galls vary in size from a pin head to compound galls of more than 2.5 cm in diameter. They are irregular, spherical or spindle shaped and most often found on tender rootlets. These structures host one to several hundred female nematodes, which remain stationary throughout their life cycle and feed inside the root.
In light of their global economic impact on commercial crops, there is an urgent need to find an efficient way of controlling root-knot nematodes. Until now, chemicals such as methyl bromide or ethyl dibromide have been used to control nematodes. However, development of resistance by the pathogens to nematicidal chemicals, as well as a heightened awareness of short and long term ecological damage caused by these and other chemicals, have increased interest in developing a bio-nematicidal product which acts specifically against its target nematode without causing ecological damage.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide bacterial strains having nematicidal activity against root-knot causing nematodes.
It is a further object of the present invention to provide an agricultural composition useful for protecting plants against root-knot nematodes.
It is an additional object of the present invention to provide a method of controlling plant-pathogenic nematodes.
In accordance with the present invention, new bacterial strains of the species B. firmus have been found which possess a nematicidal activity. These two bacterial strains are termed herein as Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562. Both strains have been deposited with the Collection Nationale de Cultures de Microorganismes (CNCM), Institute Pasteur, France, at the following date and under the following Accession Nos.:
Strains
Deposit date
Accession No.
Bacilius firmus strain
May 29, 1995
CNCMI-1582
Bacillus cereus strain
April 13, 1995
CNCMI-1562
Use of the Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 strains is currently a preferred embodiment of the invention. Other strains useful in accordance with the present invention are various mutant strains derived from the Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 strains which possess nematicidal activity. Mutant strains are at times obtained spontaneously but can also be obtained by mutagenesis, e.g. by the use of irradiation or mutagens. As will be appreciated by the artisan, it is possible to induce various kinds of mutations which will not cause a substantial change in the bacteria's nematicidal activity and their ability to exert this nematicidal activity when administered to soil in which the crops to be protected grow.
The present invention thus provides, by one of its aspects, a strain of bacteria belonging to the species B. firmus and possessing nematicidal activity, such strain being a member of the group consisting of EIP-N1 (CNCM I-1556), EIP-N2 (CNCM I-1562), and nematicidally active mutants of said Bacillus firmus strain CNCM I-1582 or Bacillus cereus strain CNCM I-1562.
Also provided by the present invention are pure cultures of bacteria, selected from the group consisting Bacillus firmus strain CNCM I-1582 or a Bacillus cereus strain CNCM I-1562 nematicidally active mutant of said Bacillus firmus strain CNCM I-1582 or Bacillus cereus strain CNCM I-1562.
According to another aspect of the present invention there is provided a nematicidal composition for use in plant protection comprising as active ingredient an effective amount of a nematicidal bacteria or of spores thereof, the bacteria being of a strain selected from the group consisting of Bacillus firmus strain CNCM I-1582 Bacillus cereus strain CNCM I-1562 and a nematicidally active mutant of said Bacillus firmus strain CNCM I-1582 or Bacillus cereus strain CNCM I-1562 together with a carrier compatible with the nematicidal bacteria.
In accordance with the preferred embodiment of the invention, the composition is supplemented by one or more supplements which improve or intensify the ability of the bacteria to exert their nematicidal activity. Supplements, may for example be nutrients such as gelatin, gelatin hydrolysate, cotton seed meal and casein hydrolysate.
According to another aspect of the present invention, there is provided a method for controlling plant-pathogenic nematodes, comprising applying to the plant roots or to the soil environment in which the plant grow, an effective amount of bacteria or spores thereof, the bacteria being of a strain selected from the group consisting of Bacillus firmus strain CNCM I-1582 Bacillus cereus strain CNCM I-1562 and a nematicidally active mutant of Bacillus firmus strain CNCM I-1582 or Bacillus cereus strain CNCM I-1562. The bacteria may be introduced into the soil by applying the bacteria under the soil within a liquid carrier. Alternatively, the bacteria may also be in a dry formulation and admixed with the soil, e.g. prior to planting or seeding. The bacteria may also be applied by impregnating plant roots or seeds prior to planting or seeding thereof into the soil, with a liquid formulation comprising the bacteria.
Another aspect of the present invention is a pot mix comprising bacteria of the invention.
The bacterial strains of the present invention are useful in controlling nematodes causing root-knot disease, and particularly those which belong to the Meloidogyne spp. However, the bacteria of the invention may also be effective against other pathogenic nematodes such as cyst nematodes.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 shows results of experiments in which the activity of Bacillus firmus strain CNCM I-1582 (), Bacillus firmus strain CNCM I-1562 () in controlling nematodes, as compared to control (), was determined under greenhouse conditions.
FIG. 2 shows results of a similar experiment to that shown in FIG. 1, obtained in microplots.
The present invention will be better understood from the following detailed description of preferred embodiments, taken in conjunction with the following figures, which summarizes the results of a number of experiments in which the strains of the invention were used to control the pathogenic activity of nematodes in the greenhouse or in microplots.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Materials and Methods
I. Identification
The strains were sent to the Deutsche Sammlung von Mikro-organismen und Zellkuturen GmbH (DSM) for identification, using partial 16S rDNA sequence hybridization.
II. Growth Conditions
The strains grow on MBS liquid medium (medium for bacillus sporulation) containing:
GE 90F (commercial hydrolysate of gelatin)—10 gr/L Bacillus firmus strain CNCM I-1582 or tryptose—5 gr/L Bacillus cereus strain CNCM I-1562;
Yeast extract—2 gr/L;
KH 2 HPO 4 —6.8 gr/L;
and the following trace elements:
MgSO 4 .7H 2 O—0.3 gr/L;
MnSO 4 —0.02 gr/L;
FeSO 3 —0.02 gr/L;
ZnSO 4 .7H 2 O—0.02 gr/L;
CaCl 2 —0.2 gr/L;
pH: 7.4 (adjusted with NaOH).
EIP-N2 can also grow on Nutrient agar medium (Difco).
The strains were grown in either 2-liter Erlenmeyer flasks or in 100-500 liter fermentors in a batch fermentation for 48-72 hours at a temperature of 30° C. The Erlenmeyer was agitated at a speed of 180 RPM.
III. Counting
The medium was centrifuged (5000*g, 20 min, RT) and the pellet containing a mixture of spores and vegetative cells was dissolved in a small amount of distilled water. Samples were seeded before and after heating at 70° C. for 10 min for counting the total cell number and the number of spores, respectively.
The total spore number is usually 75-90% of the total cell count. A typical yield is 5·10 S spores/ml.
IV. Stability
The spores showed 100% viability after 6 months in a dry form at room temperature. The spores can also be stored under the following conditions:
1) As a paste at −70° C. for at least six months;
2) By freeze-drying of spores in 10% skim milk solution and storage at 4° C.;
3) In slants stored at 4° C.;
4) The spores can be dried in an oven in the presence of peat moss or silica.
Under the last three conditions, the viability is for at least one year.
V. Proteolytic Activity
Proteolytic activity was determined by measuring the increase in optical density as a result of the release of a colored product into solution following the breakdown of Azocasein (Sigma).
The reaction mixture (1 ml) contained 6 mg Azocasein in 0.5 ml and 0.5 ml from the supernatant of the growth medium, 0.05 M Tris HCI buffer PH 7.6 containing 5 mM CaCl 2 . The reaction mixture was incubated for 15 min at 37° C., and the reaction was terminated by the addition of 0.5 ml of 10% TCA. Following an additional incubation of 30 min on ice and centrifugation (10,000 RPM, 15 min), the increase in optical density at a wavelength of 400 nm was determined vs. a control (1 ml of reaction mixture without growth medium supernatant).
VI. Collagenolytic activity
Collagenolytic activity was assayed by following the cleavage of a synthetic peptide (4-Phenylazobenzyloxycarbonil-Pro-Leu-Gly-D-Arg) by collagenase, and determining the amount of colored product released into the solution.
The reaction mixture included 0.5 ml supernatant of the growth medium, 2 ml of the synthetic peptide (stock solution contained 10 mg peptide in 0.1 ml methanol and 10 ml veronal buffer PH 7.6), and 0.25 ml of 50 mM N-Ethylmaleimide.
The mixture was incubated at 37° C. for 20 min and the reaction was terminated by the addition of 1 ml of 0.5% citric acid and 5 ml of ethyl acetate mixture to 0.5 ml of the reaction mixture. Following agitation for 20 sec, the solution was separated into two phases of which the upper phase was separated and its absorbance determined at a wave length of 320 nm. 1 O.D./6·10 7 cells equals 1 enzyme unit.
VII. Application Techniques
1. Mixing spores with soil in the presence or absence of supplements (5·10 7 spores/gr soil): in pot experiments, 500 gr of soil were used, while in microplot tests, buckets containing 15-30 kg soil were used. The chemical agent used as a control in the microplot tests is Nemacur® (Bayer).
2. Addition of spores formulated in peat moss or silica to pot soil or to seedling growth chambers: spores were mixed with either peat moss or silica and dried out in an oven (40° C., overnight) prior to application.
VIII. Nematicidal Activity Assay
In all the experiments, tomato seedlings (Na′ama strain) were used. Soil was artificially infested with 0.7 nematodes/gr soil, and the seedlings were planted in the infested soil. Larvae were prepared from egg masses developed on tomato roots. Each trial continued for 30 days.
The quantitation is based on percent change in a “Galling Index” scale ranging between 0-5, whereas “0” represents no galls on the roots and “5” represents maximum root infestation.
Results
I. Bacillus firmus strain CNCM I-1582
The Bacillus cereus strain CNCM I-1562 strain was isolated from soil obtained from the central plain area of Israel, following greenhouse pot experiments during which the soil was enriched with 0.3% cotton seed meal (CSM) prior to plantation with tomato seedlings. After 30 days, the soil was homogenized in water and a sample was seeded on agar plates which served as a source for the isolation of EIP-N1 strain.
Bacillus firmus strain CNCM I-1582 showed highest sequence similarity (98.7%) to Bacillus firmus. B. firmus has been previously identified as a potential biological control agent against Botrytis cinerea (Yildiz, F., J. of Turkish Phytopathology (1991), 30, 11-22), and has also been identified as a new insect pathogen for a lepidoptera pest of Ailanthus triphysa (Varma, R. V., et al., J. of Invertebrate Pathology. (1986), 47, 379-380). However, there have not been any reports regarding nematicidal activity by this bacteria.
II. EIP-N2
Bacillus cereus strain CNCM I-1562 strain was isolated from a mixture of filtered sterile soil and 0.05% cotton seed meal (CSM) following a tube experiment in which tomato seedlings were planted. Ten days later the soil was homogenized in water and a sample was seeded on agar plates which served as a source for isolation of the Bacillus cereus strain CNCM I-1562 strain.
The Bacillus cereus strain CNCM I-1562 strain showed the highest sequence similarity to the following Bacilli species: B.medusa (99.3%); B.cereus (99.3%); B.thuringiensis (99.3%); and B.mycoides (99.3%). Further testing has indicated that Bacillus cereus strain CNCM I-1562 belongs to the B. cereus species.
III. Enzymatic Activity
The proteolytic and collagenolytic activities Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 (vegetative cells) as compared to other microorganisms were determined, and the results are shown in Tables I and II, respectively. It can be seen that the strains of the invention have significantly higher activity than the other microorganisms.
Without restricting the invention in any way, it is believed that proteolytic and collagenolytic activities play an important role in control of nematodes, either by direct effect on the cuticle of the nematode, or indirectly by increasing the release of ammonia which is known to be toxic to nematodes due to protein breakdown.
TABLE I
Proteolytic Activity
Strain
Species
O.D./1.8 · 10 9 CFU
20M
Telluria mixta
0.238
555TT
Bacillus
13.680
CNCMI-1582
B. firmus
27.000
CNCMI-1562
B. cereus
15.500
201
Pseudomonas
0.117
203
Bacillus
0.118
122
Bacillus
2.590
TABLE II
Collagenolytic Activity
No. of
Enzyme
Bacteria
Species
O.D.
cells/100 μl
units
CNCMI-1562
B. cereus
0.37
3 · 10 6
7.4
C1
Pseudomonas putida
0.32
6 · 10 7
0.32
#122
Bacillus
0.78
3.5 · 10 5
134
#203
Bacillus
0.34
1.3 · 10 7
1.56
#201
Pseudomonas
0.44
5 · 10 6
5.28
20M
Telluria mixta
0.71
2 · 10 6
21.3
C10
Pseudomonas cepasia
0.28
2.2 · 10 7
0.76
B 3
B. cereus
0.84
6.2 · 10 6
8.12
555TT
Bacillus
0.58
2 · 10 5
174
CNCMI-1582
B. firmus
0.40
6.1 · 10 5
40
IV. Nematicidal Activity
Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 spores show a consistent and significant bionematicidal activity against root-knot nematodes under greenhouse as well as microplot conditions.
The results of a large number of experiments in which the nematicidal activity Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 against Meloidogyne spp. nematodes was determined under greenhouse conditions are summarized in FIG. 1 and the results in microplots are summarized in FIG. 2 . The numbers in parenthesis in FIG. 1 indicate the number of trials averaged into the results, while the results in FIG. 2 are averages of 5 experiments. The diseased plants were treated with no bacterial spores (), Bacillus firmus strain CNCM I-1582 () or Bacillus cereus strain CNCM I-1562 (). The following supplements were used in the experiments: a) none; b) gelatin; c) gelatin hydrolysate; d) gelatin+cotton seed meal; e) casein hydrolysate; and f) Nemacur®.
When bacterial spores alone (no supplement added) were applied to the plants, there was a 40-50% reduction in root-knot nematode infestation as compared to the control in which no bacteria was added, both in greenhouse and microplot trials. When supplements such as gelatin (0.2% w/w) or a mixture of gelatin and cotton seed meal (CSM) at concentrations of 0.05% and 0.25%, respectively, were applied to the plants without bacteria, there was a reduction of 30-40% in the galling index. However, when both bacteria and supplement(s) were added together, there was an additive, intensified effect resulting in a decrease of 9-100% and 70% in the galling index in greenhouse and microplot trials, respectively. Similar results were obtained with hydrolysates of gelatin and casein.
Other supplements, either alone or in combination can be used to increase the nematicidal activity of the bacteria. These include vegetative grains such as pea, bean and humus flours, and extracts from animal sources such as feather powder, powdered meat and other inexpensive protein hydrolysates. Examples of preferred supplement combinations are crude gelatinous material and CSM, or whey protein and CSM, at concentrations of 0.1% and 0.25%, respectively.
Spores formulated in peat moss or silica prior to mixing with pot soil in the presence or absence of supplement showed the same nematicidal activity as compared to the regular application technique described above.
In general, the bacteria and the supplements had a positive effect on the top fresh weight of the tomato plant. When used separately, they increased the top fresh weight by 50-100% as compared to control. However, when used in combination, the bacteria and supplement gave an increase of 200-300%.
V. Stability The Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 strains showed superior long-term stability with respect to nematicidal activity over numerous other strains, some of which appear in Tables I and II. For example, the 555TT strain which showed high collagenolytic activity had poor stability at RT or 4° C.
In summary, the Bacillus firmus strain CNCM I-1582 and Bacillus cereus strain CNCM I-1562 strains were chosen due to their superior performance in the three categories of nematicidal activity, enzyme activity and stability.
VI. Nematicidal Compositions
A typical nematicidal composition will include the active ingredient Bacillus firmus strain CNCM I-1582 or Bacillus cereus strain CNCM I-1562 spores), an appropriate supplement, a carrier which is compatible to the activity of the spores as well as to the plant being treated, and, preferably, a surfactant. Examples of supplements which may be added are 0.1% Scanpro™ 210/F (crude gelatinous material)+0.25% CSM, or 0.1% AMP™ 800 (whey protein)+0.25% CSM.
The composition can be modified in accordance with the application technique by which it will be used: 1) application through the irrigation system; 2) mixing in the soil of the plants; 3) seed coating.
The bacterial strain EIPN-1 identified herein as CNCM I-1556 has been replaced by CNCM I-1582, which is equivalent.
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A biologically pure strain of Bacillus firmus (CNCM I-1582) possessing nematicidal activity is provided. Also provided are compositions containing and methods for employing the Bacillus firmus strain and a biologically pure strain of Bacillus cereus (CNCM I-1562) possessing nematicidal activity. Nematicidally active mutants of these strains are also provided. Further disclosed are nematicidal compositions for use in plant protection based upon these bacterial strains or mutants thereof. Further disclosed are methods for controlling plant-pathogenetic nematodes which include use of these bacterial strains or mutants thereof. The strains find utility in controlling root-knot disease causing nematodes, for example those belonging to the species Meloidogyne.
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CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 08/152,489, filed Nov. 12, 1993 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the operation and control of theatrical lighting systems for lighting design and performance. More particularly, the invention employs a local area network receiving control information from master consoles and other input devices and distributing that information through node controllers connected to the network with interfaces to lighting and effects control devices, such as dimmer racks, and remote monitoring and input stations.
2. Prior Art
Theatrical lighting for live performances and movie and television production continues to increase in complexity. A typical theater employs hundreds of separate lights and lighting systems for house lights, stage lights, scenery lighting, spotlights and various special effects. Typically, individual lights or groups of lights are controlled through dimmers, which are located at remote locations from the lights for environmental considerations such as noise and temperature control. Individual dimmers are mounted in racks, which contain power and signal distribution to the individual dimmers.
Control of dimmer racks has been provided through lighting consoles, which allow adjustment of individual dimmers. Recent advances in lighting consoles have allowed flexibility in the number and use of individual controls allowing ganging of slide controls for simultaneous operation, sequencing of controls for multiple light settings and memory of various setting requirements. Master control panels have previously been wired directly to dimmers being controlled or, as a minimum, to dimmer racks, which provide signal distribution to individual dimmers. Industry standards for communication between control consoles and dimmer racks has been established by the United States Institute for Theater Technology, Inc. ("USITT"). Multiplexed data transmission of information to dimmers from controllers using analog technology has been established by the USITT in a standard designated AMX192. Similarly, digital data transmission between controllers and dimmers has been established by the USITT in a standard identified as DMX512.
Slight modifications and additions to the DMX protocols and capabilities have been made by various industry members. Colortran, Inc., for example, employs a modified DMX protocol identified as CMX.
The AMX192 and DMX512 standards provide flexibility over direct hardwired systems for individual dimmer control, however, significant limitations on the number of dimmers which may be controlled and the flexibility and timing of the control signals are present in these industry standards. While wiring requirements have been significantly reduced, AMX and DMX systems still require direct hard wiring from controllers to dimmer racks, with consequent limitation as to physical location and severe limitations on flexibility of rearrangement of dimmer rack locations and controller locations, depending on changing theater needs.
The AMX and DMX dimmer and controller standards further do not provide the capability for interactive control with feedback from the dimmer systems to controller consoles at a level necessary for enhanced lighting design and real-time control.
The present invention overcomes the shortcomings of the prior art by allowing control of a significantly expanded number of dimmers, while providing the capability for feedback control from the dimmers. Further, the system allows flexible placement of control consoles, monitoring devices and dimmer racks themselves, with minimal wiring requirements. The system remains downward compatible, allowing continued use of DMX and AMX hardware systems as elements of the network.
SUMMARY OF THE INVENTION
The theatrical lighting control network of the present invention is integrated in a local area network (LAN). The embodiments disclosed in this specification employ thin Ethernet technology, however, other standard LAN technologies are applicable. A master control console and associated display and peripheral devices provide overall control for the system. Standard DMX outputs are provided by the control console for use in hardwired dimmer racks, and communication with the LAN is provided through an integral network controller or network interface card (NIC). Individual node controllers are placed on the network at medium attachment units (MAU), available at desired locations on the coaxial cable net. The coaxial cable provides the only necessary hardwired portion of the system.
Remote display and control devices are operable through node controllers configured as peripheral node controllers (PNC). Dimmer racks are attached to node controllers configured as network protocol converters (NPC). NPCs additionally employ inputs which receive standard DMX/AMX control data, allowing interfacing of existing equipment consoles for secondary or supplemental control. NPCs provide standard outputs with DMX/AMX capability for connection to existing equipment dimmer racks. A microprocessor and memory storage capability within the NPC provide the capability to control the LAN interface, DMX/AMX hardwired inputs and DMX/AMX outputs. The internal intelligence in the NPC allows control input through the LAN, with priority determination and "pile-on" of multiple control signals received on the LAN and direct DMX/AMX control inputs. Memory is provided in the node controller for storage of multiple "looks", which define individual dimmer settings for an entire dimmer rack for each "look". Stored "looks" may be recalled to achieve desired lighting effects without the requirement for a master console operating on the LAN. The microprocessor in the NPC automatically institutes one or more prestored "looks" upon loss of signal from the master console through the LAN. Supplemental analog inputs and outputs and hardwired configuration switching enhances flexibility of the NPC for monitoring and control functionality.
System configuration is accomplished through a standard personal computer (PC) or the master console attached to the LAN for upload and download of configuration data to the node controllers.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention will be better understood with reference to the following drawings and detailed description:
FIG. 1 is a block diagram of the overall theatrical lighting control network showing various components of a first embodiment of the system;
FIG. 2 is a block diagram of an exemplary master console interfacing to the network;
FIG. 3 is a block diagram of an embodiment of the video peripheral controller configuration for a node controller;
FIG. 4 is a block diagram of an embodiment for the protocol converter configuration for a node controller;
FIG. 5 is a block diagram of a standard dimmer rack interface;
FIG. 6 is a software flow diagram for the elements of a protocol converter; and
FIG. 7 is a block diagram of a networked dimmer rack with an integral protocol converter.
DETAILED DESCRIPTION OF THE INVENTION
The elements of the theatrical lighting control network for a representative embodiment are shown FIG. 1. the local area network for the embodiment shown in the drawings comprises a thin Ethernet system employing coaxial cable 100, which is installed in the theater, sound stage or other application location. Medium attachment units (MAU) 102 are located throughout the cable network at desired locations to allow interfacing to the network. In the embodiment shown, the MAUs comprise standard BNC T-connectors. The LAN cable network employs standard terminators 104 to define the extent of the network.
A master console 106 is provided in the system for operator control of the various lighting systems. Standard panel operator devices, such as level slide controls 108, ganged slide controls 110 and dedicated function keys 112, are provided for control. In the embodiment shown, a standard configuration of 96 slides for individual dimmer control are provided. Status display for the operator is provided on two text displays 114, with programming and operator system information provided on graphics display 116.
Additional control input devices, such as a hand-held remote 118, submaster outrigger slide panels 120 and Magic Sheet 122, a lighting designer control tablet produced by Colortran, Inc., supplement the primary panel operator controls for the master console. Programming control and computer functions interface in the master console is provided through standard keyboard 124 and track ball 126 inputs. A printer 128 is provided for hard copy of lighting designs and other output information from the master console.
An integral LAN interface in the master console connects to the coaxial cable for data communication through the LAN. DMX/CMX outputs 130 are provided from the master console for direct hardwired connection to DMX/CMX dimmer racks 132, which are not on the network.
Additional master consoles can be incorporated into the network at desired locations for duplicate control of common dimmers or additional control of separate dimmers, as will be discussed in greater detail subsequently.
FIG. 2 discloses, in block diagram form, the internal configuration of an exemplary master controller. Overall operation of the master controller is accomplished through a master single-board computer (SBC) 210 incorporating a processor and integral memory. Current 486-based SBCs provide adequate capability for system requirements. Operator device interfaces 212 connect directly with the SBC for communication with programming devices, such as the standard keyboard and track ball, and supplemental external controllers and peripherals, such as the handheld remotes, Magic Sheet, and hard copy printer. A processor communications bus connects the SBC to a multiple display controller 216 for the text and graphics displays and to a calculation coprocessor 218 and device control processor 220 to supplement the processing capability of the SBC. A calculation coprocessor allows rapid computation of light levels for dimmers controlled by the master console based on the various control inputs. The device control processor provides an interface for the panel operator devices, generally designated 222, which include the slide controllers and designated function keypad inputs. In addition, direct output of DMX/CMX data is provided through the device control processor to a DMX/CMX interface 224.
A network controller 226 communicates to the SBC through the processor bus and attaches the master console to the LAN through network interface 228.
Referring again to FIG. 1, the other elements of the system are attached to the network through node controllers connected at desired locations through the BNC T-connectors. Remote monitoring and control input to the system is accomplished through peripheral node controllers (PNCs). A first PNC type specifically configured for attachment of video monitors and control devices is demonstrated in the embodiment shown in the drawings as the video peripheral controller (VPC) 134. VPCs are located on the network for use by designers, stage managers and others to monitor, control or design lighting remote from the master console. Devices supported by a VPC include remote text displays 136, remote graphic displays 138, dedicated function key input devices, such as remote keypads, 140, designer remotes 142 and Magic Sheets 144, remote submaster outriggers 146 and hand-held remotes 148. Exemplary use of the VPC would be a stage manager's booth backstage in a theater, allowing the stage manager to view lighting cues on the text display to coordinate scene cues, actor entrances, etc.
A second NPC configuration identified in the embodiment shown in the drawings constitutes an RF device interface 150, which provides communications through a radio frequency link 152 to roving design and control devices, such as Magic Sheets, designer remotes and hand-held remotes incorporating RF transceivers.
The internal configuration of an exemplary VPC is shown in FIG. 3. The VPC is connected to the LAN through a network interface 300, which communicates through network controller 302 to a microprocessor 304 on the microprocessor bus 306. The microprocessor controls the VPC, providing output to displays through a multiple display controller interface 308 connected to the processor bus, and providing direct connection to the hand-held remote and other operator devices, generally designated 310.
Other PNCs, such as the RF device interface, employ a similar structure to that disclosed in FIG. 3, with appropriate interface modifications, such as the addition of an RF link between the microprocessor and operator devices. Flexibility obtained through the use of a network in the present invention allows PNCs to be developed with single or plural interfaces which may be attached at any T-connector on the LAN.
Control of lighting dimmer racks in the system via the LAN is accomplished through node controllers configured as network protocol converters (NPC) 154 in FIG. 1. NPCs incorporate an integral LAN interface and provide direct DMX/CMX/AMX controller inputs. Devices such as non-networked control consoles are connected to these inputs for direct control of dimmers attached to the NPC.
Outputs from the NPC are provided to drive AMX dimmer racks 156 and CMX/DMX dimmer racks 158. The flexibility of the present system allows the use of dimmer racks of any size including standard dimmer racks having 12, 24 or 48 single or dual dimmer modules (96 dimmers per rack). The present configuration of the embodiments shown in the drawings allows designation of up to 8,192 dimmers for control on the LAN, with up to 4,096 dimmers controlled through an individual master console.
FIG. 4 demonstrates a present embodiment of the NPC. A master microprocessor 400 provides overall control of the NPC. The master microprocessor communicates through a processor bus 402 with a slave mode microprocessor controller 404. An erasable programmable read-only memory (EPROM) 406 and random access memory (RAM) 408 provide control software and operating data storage capability for the NPC. A network controller 410, connected to the bus, provides communications to the LAN through a network interface 412. Communications with the dimmers is provided through DMX/CMX/AMX input/output interfaces 414.
Additional interfaces for alternate control devices, such as a hand-held remote 415, can be incorporated in the NPC for additional local control flexibility. As previously described, direct connection of DMX/CMX/AMX control devices to these interfaces allows non-networked control inputs into the NPC. In addition, an analog input interface 416, in combination with an analog to digital converter 418 and an analog output interface 420, in combination with a digital to analog converter 422, provide direct analog input and output capability for the NPC for functional monitoring and control of the dimmer rack. In the embodiment shown in the drawings, between 8 and 24 analog inputs and outputs are provided.
The internal intelligence in the NPC provided by the master microprocessor and data storage capability allows the NPC to control complete configuration of the racks and dimmers connected to the NPC. A node name specifically identifying each NPC allows specified communication on the network and network source identification numbers of consoles or other input devices providing dimmer data input to the NPC are stored in memory. In the embodiment shown in the drawings, up to 16 controllers may be present on the network, providing 16 I.D.'s for controller definition to the NPC. Availability of the dimmer data inputs for access by a controller and enabled/busy status for the inputs allows control of data received over the LAN by the NPC. Protocol types for the various control inputs are established, and source I.D.'s and priorities for "pile-on" of control data for the dimmers is provided. In the embodiment shown in the drawings, up to 7 DMX/CMX controllers, including both LAN and direct input to the NPC, can be piled-on with priority. Each controller in the system is given a priority of 5-to-1, or 0, with 5 being highest priority. Controllers with the same priority pile-on and ignore contributors of a lower priority. Priority 0 always piles-on for control selection.
Multiple profile definitions for dimmers in the rack are stored and identified in memory for selection for individual dimmers. Rack level control parameters are provided through the analog input interface to the NPC with control outputs, such as fan activation, through the analog output interface.
Individual dimmer parameters such as dimmer capacity and confituration are stored in memory in the NPC and individual dimmers may be named per dimmer circuit. A remap table for logical-to-physical definition of the dimmers in the rack is stored. Individual dimmer parameters, such as target load, line regulation, cable resistance, response time, minimum and maximum values, phase control parameters, dimmer profile and dimmer alarm settings (over-temperature and load sensing) are stored for each dimmer.
The NPC incorporates an external data storage interface 424 connected to the microprocessor bus for uploading and downloading NPC configuration to non-volatile storage, such as a memory card or magnetic disk system. A serial interface 426 is provided in the NPC for direct connection of a personal computer or other device for configuration definition, as will be described in greater detail subsequently.
The data contained in the NPC may be monitored and/or updated through the LAN. This allows operators, designers, stage managers and others to receive direct feedback regarding operation of dimmers in the system. The flexibility afforded by the LAN in distribution of dimmer control data is also equally applicable to system feedback, which can be obtained at any LAN-connected console or VPC.
Exemplary feedback parameters provided through the LAN for monitoring in the system include individual dimmer name, control level (0-100%), output voltage, low load condition, overtemp condition and dimmer type.
Memory capability in the NPC allows storage of a plurality of "looks" as previously described. Settings for the full compliment of dimmers controlled through the NPC are stored. In the present embodiment shown in the drawings, storage capacity for 99 "looks" is provided. The master microprocessor in the NPC monitors control data provided by the LAN and/or local controllers. Upon loss of signal from the controllers, the microprocessor automatically institutes a preprogrammed "look." Access to other "looks" stored in the memory can then be accomplished through a local controller, such as the hand-held remote. Changes between "looks" are automatically formatted by the NPC based on the dimmer parameters previously described.
An exemplary embodiment for the dimmer racks used in the system is shown in FIG. 5. Dimmer data input to the rack is received on a DMX/CMX/AMX interface 500 connected to a microprocessor 502. The microprocessor decodes the dimmer data received and provides output to the dimmers through a digital-to-analog converter 504, providing direct pulse width modulation (PWM) output for "dumb" dimmers or through a universal asynchronous receiver/transmitter (UART) 506 for data transmission to "smart" dimmers. An analog interface 508, with associated A-to-D converter 510, is provided for input of analog configuration or control parameters to the rack. Program and data storage for the microprocessor is provided in EPROM 512 and RAM 514.
The configuration of the node controllers of the system is accomplished through the use of a personal computer 162 attached to the network as shown in FIG. 1. Definition of all parameters and settings for each NPC are determined and entered into the PC prior to operation of the networked lighting system. The node configurations are then downloaded either through the LAN to the various nodes or the PC is individually attached to each node through the serial port and the node is preconfigured prior to attachment to the LAN.
In the embodiment disclosed herein, the necessary configuration settings of an NPC are the network name, dimmer source IDs of node input ports and Master Console dimmer data, pile-on assignments of output ports, remap assignments of source ID dimmers to output dimmers, DMX/CMX/AMX input protocol timing and enabling, and DMX/CMX/AMX output protocol timing and enabling. The only necessary configuration setting of a VPC is the network name.
FIG. 7 discloses, in block diagram form, an integration of the NPC into the dimmer rack. Dimmer racks with integrated nodes 160 for direct connection to the LAN as shown on FIG. 1 employ the architecture of the embodiment shown in FIG. 7. The functions of the master microprocessor and slave mode controller of the NPC of FIG. 6 are duplicated by the master microprocessor 700 and slave mode controller 702, with the master microprocessor controller additionally assuming the functions of the microprocessor 500 of the rack in FIG. 5. A device interface 704 for hand-held remote or rack monitor provides direct communication to and from the integrated rack, with control level inputs received through DMX/CMX input interfaces 706 or through the LAN via the network interface 708 and network controller 710, which is attached to the microcontroller bus for direct communication to the master microprocessor. An analog interface 712 and associated A-to-D converter 714 provide analog input to the slave mode controller for control functions. Multiple hardwired configuration switches located internal or external to the rack connect to signal lines 716 feeding direct configuration data to the slave mode controller.
Presence of the NPC integral with the rack precludes the need for intermediate communications from the NPC to the rack via DMX/CMX protocols. The master microprocessor provides direct output to a dimmer firing engine 718 with associated memory 720 for output of PWM data to "dumb" dimmers. Similarly the master microprocessor provides data directly to UART 722 for control of "smart" dimmers which, in turn, provide return communications through the UART to the master microprocessor.
The memories 724 and 726, serial interface 728 and external data storage interface 730 have similar functions to the NPC components described with regard to FIG. 4.
The slave mode controller and master microprocessor of the integrated rack provide sensing of power, temperatures and fan condition through A/D converter 732 and can provide that status data to the network.
Finally, the integrated rack provides a control output as a NPC for a companion standard DMX/CMX rack through DMX/CMX output interface 734.
A functional diagram of software for an NPC of the embodiments in the drawings providing control to dimmer racks 160 of FIG. 1 and illustrated in FIG. 7, is shown in FIG. 6. The bubbles in FIG. 6 identify the processes of the software, while arrows in the figure show data flow and hash-lined descriptions designate data storage. The initial process identified as LEVEL CALCULATION, PILE-0N AND REMAP 610 receives inputs from the DMX direct connection consoles, NETWORK CONTROL LEVELS from the master console on the LAN and other ANALOG INPUTS. The LEVEL CALCULATION calculates the desired level for each controllable element in the system from the inputs and, based on the PILE-ON, REMAP, MIN./MAX. and other data contained in the DIMMER CONFIGURATION data. The output of defined levels is provided to the DIMMER FIRING PROCESS, INCLUDING LINE REGULATION subroutine 612, which applies the DIMMER PROFILE provided from the DIMMER CONFIGURATION data based on the current line status identified by VOLTAGE A/D and ZERO CROSS data about the line. The calculated values are then output (OUT) to the rack for implementation. The CALCULATED VOLTAGES are also stored as DIMMER STATUS, and LEVELS provided from the level calculation are placed in memory as STORED LEVELS for operation by the CONFIGURE FEEDBACK AND ALARM subroutine 614, which provides data to the network for configuration and feedback and to the serial output for communication to the configuration PC. A DIMMER COMMUNICATION subroutine 616 receives additional dimmer status communications (DIMMER COMM) from the rack and provides interactive communications to "smart" dimmers for information other than level data.
The CONFIGURE FEEDBACK AND ALARMS subroutine also receives input from the LAN or serial port for defining configuration of the NPC (NODE), mode of operation (MODE) or "look" data (LOOK NO.), which may be employed by the LEVEL CALCULATION, PILE-ON AND REMAP subroutine for generation of stored "looks". Analog inputs to the LEVEL CALCULATION, PILE-ON AND REMAP subroutine may also be employed for "look" selection or back-up from LOOK BACKUP data in memory, based on failure of DMX direct or network control level input.
While the embodiments herein disclose lighting controls such as dimmers, controllers for other stage effects such as wind machines, movable light carriages and active stage props are operable with the network as defined in the present invention. Having now described the invention in detail as required by the patent statutes, those skilled in the art will recognize substitutions and modifications to the embodiments disclosed herein for specific applications of the invention. Such substitutions and modifications are within the scope and intent of the present invention as defined by the following claims.
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A theatrical lighting control network which incorporates a local area network for communication among a number of node controllers and control consoles or devices employed in establising lighting or other effects levels in a theater, film production stage or other performance environment. Use of the network eliminates the requirements for the majority of hardwiring for interconnection of consoles and other contoller or monitoring devices to effects controller racks and provides great flexibility in location and relocation of various components of the system.
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CROSS REFERENCE OF RELATED APPLICATION
This is a utility application based upon derived from and incorporating by reference a previously filed provisional application entitled Nanostructured Bioactive Material Prepared by Spray Drying Techniques filed Apr. 6, 2004 as Ser. No. 60/559,884.
REFERENCE TO RESEARCH GRANTS AND GOVERNENT LICENSE
This invention was made during research activities that were supported in part by Grants DE11789 from the NIDCR to the ADAF and carried out at the National Institute of Standards and Technology.
BACKGROUND OF THE INVENTION
In a principal aspect the present invention comprises apparatus and preparation methods, by a spray drying technique, for nanostructured bioactive material that has high reactivity derived from small particle sizes and high surface areas comprising the material. Such manufactured material has performance advantages in a range of biomedical applications.
The mineral component of bone and teeth consists primarily of non-stoichiometric and highly substituted hydrozyapatite (HA) in poorly crystalline or nearly amorphous forms. The “impurity” components that are present at significant levels in biominerals include sodium, potassium, magnesium, and strontium substituting for calcium, carbonate for phosphate, and chloride and fluoride for hydroxyl ions. Because HA is stable under in vivo conditions and is osteoconductive, synthetic HA has been widely used in hard tissue repair application, such as implant coatings and bone substitutes. Other calcium phosphate phases have also been shown to be highly biocompatible and/or osteoconductive. As a result, with the exception of fluorapatite (FA), all calcium phosphate compounds listed in Table 1 have been used in some form of bone repair applications.
TABLE 1
Calcium Phosphate Compounds that Have Being Used in Bone Repair Applications
Compound
Formula
Bone repair applications
Monocalcium phosphate
Ca(H 2 PO 4 )2H 2 O
Components of calcium phosphate
monohydrate (MCPM)
cement (CPC) [Mejdoubi et al.,
1994]
Dicalcium phosphate
CaHPO 4
CPC component [Brown and Chow,
anhydrous (DCPA)
1987]
Dicalcium phosphate
CaHOP 4 2H 2 O
CPC product [Bohner et al., 1995]
dehydrate (DCPD)
CPC component [Brown and Chow,
1987]
Octacalcium phosphate
Ca 8 H 2 (PO 4 ) 6 5H 2 O
CPC product [Bermudez et al., 1994]
(OCP)
α-Tricalcium phosphate
α-Ca 3 (PO 4 ) 2
CPC component [Ginebra et al. 1997]
(α-TCP)
β-Tricalcium phosphate
β-Ca 3 (PO 4 ) 2
CPC component [Mejdoubi et al., 1994]
(β-TCP)
Granular bone graft [Ogose et al., 2002]
Amorphous calcium
Ca 3 (PO 4 ) 2
CPC component [Lee et al., 1999]
phosphate (ACP)
Hydroxyapatite (HA)
Ca 5 (PO 4 ) 3 OH
CPC product [Brown and Chow, 1987];
granular bone graft [den Boer et al.,
2003]; Implant coating [Jaffe and
Scott, 1996]
Fluorapatite (FA)
Ca 5 (PO 4 ) 3 F
Tetracalcium phosphate
Ca 4 (PO 4 ) 2 O
CPC component [Brown and Chow,
(TTCP)
1987]
Calcium phosphate compounds are also useful in various dental applications. For example, a slurry or gel that contained MCPM and fluoride was used as topical F agents that produced significant amounts of both tooth-bound and loosely bound F deposition on enamel surfaces. A chewing gum that contained α-TCP as an additive released sufficient amounts of calcium and phosphate ions into the oral cavity and significantly alleviated cariogenic challenges produced by sucrose. A calcium phosphate cement that contained TTCP and DCPA was shown to provide effective apical seal when used as a root canal filler/seal, or as a sealer with as a retrievable master cone. The cement was also effective as a perforation sealer. ACP or a TTCP+DCPA mixture has been used as the mineral source in remineralizing dental restorative materials.
In addition to calcium phosphates, a number of calcium-containing compounds also have significant dental applications. Calcium fluoride, CaF 2 , which is the major product of most topically applied F (F dentifrices, F rinses, professionally applied F gel, etc.), is the source of ambient F in the mouth that is primarily responsible for the cariostatic effects of F. The greater the amount of CaF 2 that adheres to the oral tissue surfaces after a F application, the greater is the oral F retention and therefore the F cariostatic effects. Calcium-silicate compounds, tricalcium silicate and dicalcium silicate, are the major components of mineral trioxide aggregates (MTA), a material that finds wide uses in endodontic procedures, such as root end and perforation fills and for apical closure in the apexification procedure. Calcium silicate hydrates (CSH), xCa(OH) 2 ySiO 2 zH 2 O, of varying Ca/Si/H 2 O ratios are among the products formed in MTA.
Defined broadly, the term “nanostructured” is used to describe materials characterized by structural features of less than 100 nm in average size (WTEX Panel Report on Nanostructure Nanodevices, 1999). Clusters of small numbers of atoms or molecules in nanostructured materials often have properties (such as strength, electrical resistivity and conductivity, and optical absorption) that are significantly different from the properties of the same matter at the bulk scale. In the case of calcium phosphates and other bioactive inorganic materials, one of the most small particle size and high surface areas. There are a number of reasons to believe that the combination of small particle size and high reactivity can lead to performance advantages in a range of clinical applications. For example, as set forth in the description of the preferred embedment hereinafter, experimental results showed that nano sized HA, when incorporated into a TTCP+DCPA calcium phosphate cement caused a drastic reduction in setting time from 30 min to 10-12 min. It is anticipated that nano particles of other calcium phosphate phases, which are ingredients of the various calcium phosphate cements in clinical use, will also significantly improve the setting and other handling properties, e.g., cohesiveness, injectability, etc., of the cements.
The apatite crystallites in human bone, enamel, dentin and cementum are all extremely small in size and can be considered as nanstructured materials. Because HA is the prototype for bioapatites, which are in nano crystalline forms, extensive efforts have been made to produce synthetic nano HA materials. Methods that have been used for preparing nano HA material included chemical precipitation, in some cases followed by spray drying or hydrothermal treatment, sol-gel approach, microemulsion techniques, precipitation from complex solution followed by microwave heating, wet chemical methods incorporating a freeze drying step, mechanochemical synthesis, and eletrodeposition. Additional studies reported synthesis of composites of nano HA and bioactive organic components including HA-collagen, HA-chondroitin sulfate or HA-chitosan using direct precipitation method, nano HA-polyamide using HA slurry and solution method, and Ca-deficient nano HA-high molecular weight poly (D,L-lactide) through a solvent-cast technique.
Preparation of microcrystalline and nanocrystalline HA have also been disclosed in the patent literature. U.S. Pat. No. 5,034,352 discloses that Spray drying is the preferred technique for converting the gelatinous precipitate of hydroxylapatite into the fine dry articles suitable for use in the agglomeration process. U.S. Pat. No. 4,897,250 discloses that calcium phosphate, icnlduing hydroxyapatite, precipitated by the reaction can be withdrawn in a powder form by any conventional techniques such as filtration, centrigual separation, and spray drying. U.S. Pat. No. 6,033,780 discloses that manufacturing method of the spherical apatite is that a slurry comprising hydroxyapatite as its main component is dried and powdered to prepare aggregates of primary apatite particles, preferably, spray dried to form spherical particles. U.S. Pat. No. 6,558,512 discloses that one method for preparing dense, rounded or substantially spherical ceramic particles such as calcium hydroxyapatite is by spray dring a slurry of about 20 to 40 weight % submicron particle size calcium hydroxyapatite. U.S. Pat. No. 6,592,989 provides a method of synthesizing hydroxyapatite comprising the steps of preparing a mixed material slurry be dispersing calcium hydroxide powder into a phosphoric acid solution; conducting a mechanochemical milling treatment. U.S. Pat. No. 5,585,318 provides methods for producing non-porous controlled morphology hydroxyapatite granules of less than 8 μm by a spray-drying process. Solid or hollow spheres or doughnuts can be formed by controlling the volume fraction and viscosity of the slurry as well as the spray-drying conditions. Finally, U.S. Pat. No. 6,013,591 discloses a method for preparing nanocrystalline HA that involves precipitating a particulate apatite from solution having a crystallite size of less than 250 nm and a BET surface area of at least 40 m 2 /g. In all of the prior art methods cited above, HA was precipitated from a solution. The slurry or emulsion containing the precipitated HA was spray-dried to produce fine particles.
In the above methods described in the scientific or patent literature, the nano HA materials are formed in a solution environment, and in most cases, the product is washed with water or other solvents to remove impurity or undesired components. Exposure of the nano particles to additional solution environments is likely to result in significant interactions between the particle surfaces and the solvent, leading to modifications of the surface properties and a reduction in the high reactivity innate to the nano particles. Thus, there has persisted the need to identify methods and apparatus for the manufacture of high purity, amorphous or nearly amorphous nano particles, especially those comprised of [Ca] and [P].
SUMMARY OF THE INVENTION
Briefly, the present invention comprises methods for preparing nano particles, such as HA particles, by spray drying of a solution discharged through a nozzle in such a way that the nano particles form via in situ precipitation resulting from generally controlled evaporation of the solution in a chamber. The product formed is essentially free of undesired components or impurities such that the particles do not need to be washed. Thus, the particles need not be exposed to any solution environment and therefore will retain their original, highly reactive surfaces. By adjusting the composition of the solution, e.g., the Ca/P ratio, Na and carbonate concentrations, etc., nano HA particles of a range of Ca deficiency and substitution (Na for Ca and carbonate for phosphate) can be prepared. The spray drying methods and apparatus described hereinafter can be used to prepare not only nano HA, but also nano forms of MCPM, DCPD and/or DCPA, and OCP by appropriately formulating the solution composition which is to be sprayed to form droplets from which the liquid is evaporated.
Many compounds of biomedical interest, such as fluorapatite (FA), have very low solubilities so that a saturated solution would contain little amount of dissolved material. Other compounds, such a calcium fluoride, calcium silicate, etc., have low solubilities that do not increase significantly with increasing acid strength. As a result, the one-solution spray drying method as described hereinafter may not be as commercially useful as desired for preparing nano particles of these compounds. However, availability and use of two-liquid nozzles makes it possible to prepare nano particles of these insoluble salts because the cationic and anionic components of the salt are initially present in two separate solutions each one being dispersed from a distinct, but adjacent nozzle to enable ionic combination upon atomization in a chamber.
Thus, the invention is generically described as methods comprising preparation of nano structured materials using a spray drying technique employing a one-liquid or multiple liquid nozzles. An important feature of the inventive spray drying process comprises evaporation of the liquid from which the nano particles are derived thereby leading to in situ precipitation of HA (or another compound of interest) that is essentially free of undesired components or impurities. In this way the nano particles formed do not need to be washed and therefore not be exposed to any solution environment that could modify the particle surfaces. This process requires that the solution being sprayed contain only calcium and phosphate ions (or constituent ions of the salt to be prepared) and an acid component in water solution, if needed, to solubilize the calcium phosphate compound. The acid must preferably be sufficiently volatile so that it can be readily evaporated in the spray drying process. To achieve this, the volatile acid must preferably also be a weak acid such that no significant amounts of the acid anions, which are not volatile remain present by the end of the evaporation process. Precipitation of HA, for example, resulted from evaporation of water in the spray drying process causing a decrease in solution pH to about 4.0. This, in turn, makes the weak acid become increasingly more undissociated and therefore readily evaporated. Carbonic and acetic acids are examples of good candidates for the purpose. In the specific example of HA particle formation, HA-saturated solutions can be prepared by dissolving HA in a dilute acetic acid (for example, 17.5 mmol/L) solution (acetic acid-HA solution) or carbonic acid (266 mmol/L) solution (carbonic acid-HA solution).
Other examples of the method of the invention include formation of nano particles of other components. For example, compositions of solution to be spray dried for preparing nano particles of various calcium phosphate phases are set forth in Table 2. Because MCPM is highly soluble, the solution for the nano MCPM production can be prepared by dissolving an appropriate amount of MCPM or other sources of Ca (for example CaCO 3 ) and P (for example H 3 PO 4 ) in a solution of the desired concentration (Table 2). For the preparation of nano particles of other calcium phosphates, a volatile weak acid is used to facilitate solubilization of the calcium phosphate ions. The examples in Table 2 show acetic and carbonic acid as the volatile weak acids but other acids of similar properties could also be used. With the exception of MCPM, the amount of a calcium phosphate that can be dissolved is strongly affected by the concentration of the volatile acid. Table 2 shows examples of the solubility of various salts at two concentrations of carbonic acid or acetic acid. In general, a minimum amount of the volatile weak acid, necessary to keep the calcium and phosphate ions in the solution, is used to facilitate the removal of the acid in the spray drying process.
TABLE 2
Compositions of Spray Drying Solutions for use in the Single-Liquid
Nozzle Process
MCPM-saturated solution, [Ca]/[P] = 0.5
Solvent
[Ca] mmol/L
[P] mmol/L
Water
0.1 to 2000
0.2 to 4000
DCPD/DCPA-saturated solution, [Ca]/[P] = 1.0
Acid
[Ca] mmol/L
[P] mmol/L
Carbonic Acid (H 2 CO 3 ) 1000 mmol/L
20.1
20.1
Carbonic Acid 0 mmol/L
1
1
Acetic acid (C 2 H 4 O 2 ) 996 mmol/L
109
109
Acetic Acid 0 mmol/L
0.1
0.1
OCP-saturated solution, [Ca]/[P] = 1.33
Acid
[Ca] mmol/L
{p} mmol/L
Carbonic acid 1018 mmol/L
29.6
22.2
Carbonic acid 0.04 mmol.L
0.1
0.075
Acetic acid 995 mmol/L
221
166
Acetic acid 0.04 mmol/L
0.1
0.075
ACP- or TCP-saturated solution, [Ca]/[P] = 1.5
Acid
[Ca] mmol/L
[P] mmol/L
Carbonic acid 1152 mmol/L
147
98
Carbonic acid 0 mmol/L
0.1
0.067
Acetic acid 985 mmol/L
610
407
Acetic acid 0 mmol/L
0.1
0.067
HA-saturated solution, [Ca]/[P] = 1.67
Acid
[Ca] mmol/L
[P] mmol/L
Carbonic acid 1004 mmol/L
14.2
8.54
Carbonic acid 0.164 mmol/L
0.1
0.06
Acetic acid 998 mmol/L
132
79
Acetic acid 0.122 mmol/L
0.1
0.06
The spray formation and drying process in one embodiment thus comprises introduction of a solution of the compound or compounds described through a spray nozzle (nozzles) into a heated chamber where the spray particles are deliquified thereby resulting in high purity, solid, generally amorphous, nano particles collected in a precipitation. Two nozzles may be utilized for certain applications where the compounds would not otherwise adequately dissolve in a weak acid solution.
Thus, it is an object of the invention to provide methods for manufacture of nano particles of various compounds by a process which facilitates formation of high purity particles.
Another object of the invention is to provide methods for manufacture of nano particles that is efficient, and which avoids complex procedures.
A further object of the invention is to provide a method for manufacture of nano particles by spray drying techniques.
These and other objects, advantages and features of the invention will be set forth in the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWING
In the detailed description which follows, reference will be made to the drawing comprised of the following figures:
FIG. 1 is a schematic drawing which depicts an embodiment of a spray drying apparatus useful in the practice of the invention;
FIG. 2 is an x-ray diffraction pattern for HA nano particles prepared with acetic acid in accord with the invention;
FIG. 3 is transmission electron microscope image of the HA nano particles prepared with acetic acid in accord with the method of the invention;
FIG. 4 is a high resolution transmission electron microscope image of HA nano particles prepared with acetic acid in accord with the method of the invention;
FIG. 5 is an x-ray diffraction patterns for HA nano particles prepared with carbonic acid in accord with the method of the invention;
FIG. 6 is a transmission electron microscope image of HA nano particles prepared with carbonic acid in accord with the method of the invention;
FIG. 7 is a graph depicting dissolution of HA in a pH 6 HA pre-saturated solution; and
FIG. 8 is an x-ray diffraction pattern of nano particles of CF 2 prepared in accord with an alternative method of the invention utilizing two spray nozzles.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The apparatus referring to FIG. 1 , there is depicted in a schematic view a device usefule to form nano particles. The apparatus depicted in FIG. 1 consists of a spray nozzle 10 (SUC1120, PNR America LLC, Poughkeepsie, N.Y.) situated on the top of a glass column 12 (Model VM770-48, VM Glass Co., Vineland, N.J., 6″ diameter), which is heated with electrical heating tapes (Model BIH 101100L, BH Thermal Co., Columbus, Ohio) and thermally insulated (fiberglass tape, Flextex, Montgomeryville, Pa.). Dry HEPA filtered air is supplied at the top 14 of the column, and an electrostatic precipitator 16 (MistBuster®, Air Quality Engineering, Inc., Minneapolis, Minn.) connected to the lower end of the column 12 pulls air from the column, creating a steady flow of air/mist through the column 12 . The water and volatile weak acid in the solution are evaporated into the dry, heated air in the column and are expelled from the precipitator 16 into a hood. The fine particles suspended in the flow are trapped in the precipitator 16 and collected at the end of the process.
The nozzle utilized in the apparatus is selected to provide spray droplets of minimum size. Thus, the nozzle preferably has a diameter of the nozzle outlet passage in the range of about 12 to 15 microns for the compounds tested. The temperature in the dehydration chamber is typically in the range of 100° C. to about 200° C. without dissociation or adverse impact upon the formed particles. On the other hand, materials such as DCPA and DCPD are dehydrated at a temperature adequately under 200° C. to avoid dissociation or other adverse effects upon the formed particles. Of course, the flow rate of the clean air into the system will affect temperature in the forming chamber. The air may or may not be preheated.
The size and shape of the evaporation chamber will also comprise a factor affecting air flow rates, temperature and evaporation. An arrangement which avoids spray condensing or collecting on the chamber walls is highly preferred. The pH of the acid solution is also preferably controlled for reasons noted previously and preferably is about 4.0 or less. Of course, as the liquid evaporates to leave the powder particles, the effective pH increases. A weak acid is desired to preclude inclusion of acid based artifacts in the formed particles.
Characterization of the Nano Particles
XRD (Rigaku DMAX 2200, Rigaku Denki Co. Ltd. The Woodlands, Tex.) was used to determine the crystalline phases present in the formed nano particle product. Scans were performed between 10°<2θ<50°. The estimated standard uncertainty of the 2θ measurement is 0.01° and the mass fraction of a crystalline phase to be detected by XRD is about 3%. It was anticipated that the product will contain primarily amorphous materials and the location and the intensity of the broad peak were noted.
A ThermoNicolet NEXUS 670 FT-1R spectrometer (Thermo Nicolet, Madison, Wis.) was used to record the infrared spectra of the nano powders. The formed nano particle powders were mixed with IIR quality KBr at a mass ratio of =1:400 and finely ground in a mortar and pestle. The mixture was then pressed into a pellet in a 13 mm diameter evacuated die. The sample KBr pellet to cancel the impurity bands. The absorbance spectra were acquired over the range of 400 cm −1 -4000 cm −1 using a DTGS detector and KBr beam splitter, with a resolution of 2 cm −1 . Each spectrum was scanned 32 times to increase the signal-to-noise ratio. The estimated standard uncertainty of wavelength was ±4 cm −1 .
Multipoint Brunauer-Emmett-Teller (BET) surface area analyses were done (Gemini 2375 Surface Area Analyzer, Micromeritics, Norcross, Ga.) with ultra high purity nitrogen as the adsorbate gas and liquid nitrogen as the cryogen. The pressure sequence was (0.05, 0.10, 0.15, 0.20, 0.25) P/Po and the evacuation time was three minutes. The analysis mode was equilibration with the equilibration time of 5 s. The samples were dried in air overnight at 110° C. (Micromeritics Flow Prep station) before the measurement. Analyses were conducted on replicate samples to established standard deviation. In this and other measurements in the present study, the standard deviation was taken as the standard uncertainty.
A TA Q500 thermo gravimetric analyzer (TA Instruments—Waters LLC, New Castle, Del.) was used to determine the weight loss of the nano powder sample with the increase of temperature. The temperature range was from 25° C. to 950° C., and the heating rate was 10° C./min. Estimated standard uncertainty of temperature calibration was ±5° C.
Samples of the nano materials were analyzed for calcium (Ca) and phosphate (P) by spectrophotometric methods and carbon (C) by combusting the sample at 1000° C. in a constant oxygen flow and detecting the carbon dioxide by infrared absorption using a LECO CHN 000 Analyzer (St. Joseph, Mich.) [35,36]. This information was used in conjunction with FTIR data to estimate the chemical composition of the nano samples.
Transmission electron microscopy (TEM) was used in characterizing the particles. For this purpose, particles were deposited onto Cu grids, which support a “holey” carbon film. The particles were deposited onto the support grids by deposition from a dilute suspension in acetone or ethanol. The particle shapes and sizes were characterized by diffraction (amplitude) contrast and, for crystalline materials, by high resolution electron microscope (JEOL, Peabody, Mass.), equipped with a Gatan Image Filter (with parallel EELS) and a light element EDS system.
The transient nature of the dissolution behavior of HA was taken into consideration when conducting the solubility measurements as follows. The solubility experiments were conducted by dissolving the nano HA sample in solutions pre-saturated with crystalline HA at pH (5.0, 5.5, and 6.0). Based on calculations using a commercially available software “Chemist” (MicroMath, Salt Lake City, Utah), the solutions were prepared by equilibrating crystalline HA in 8.1 mmol/L, 2.7 mmol/L, and 0.92 mmol/L phosphoric acid solutions, that also contained 150 mmol/L KNO, as an electrolyte background, until saturation followed by filtration. In each solubility measurement conducted at (21±1) ° C., a pre-calibrated combination pH electrode [60110B, Extech Instruments Co., Waltham, Mass.] and a Ca-ion specific electrode [Orion 97-20 Ion Plus, Thermo Electron Co., Woburn, Mass.] were placed in 100 mL of a HA-saturated solution under constant stirring (52.4 rad/s or 500 rpm), and stable electrode readings were recorded ever 10 s, 5 mL of the equilibrating slurry was removed at (1, 2, 3, 4, 5 and 10) min and immediately filtered for analysis of [Ca] and [P] concentrations using spectrophotometric methods [34]. The pH, [Ca], and [P] values were used to calculate solution ion activity products (IAP) with respect to HA [Eq. (1)] and other calcium phosphate phases using the software “Chemist”
IAP(HA)=(Ca 2+ ) 10 (PO 4 ) 6 (OH) 2 (1)
where quantities in ( ) on the right hand side of equation denote ion activities. Solubility measurements were conducted on replicate samples to established standard deviation.
Properties of Nano HA Prepared from an Acetic Acid-HA Solution.
Once brushed off the precipitator plates, the nano HA had the form of a white fine powder. Powder X-ray diffraction (XRD) patterns showed that the material was amorphous ( FIG. 2 ). Transmission electron microscopic (TEM) observations show clusters that contained spherical particles about 10 nm to 100 nm in diameter ( FIG. 3 ). High resolution TEM performed on particles that had been suspended in ethanol for 2 days showed packed crystalline HA particles 5 nm to 10 nm in size ( FIG. 4 ). BET measurement results showed a surface area of (mean±standard deviation, n=2) (33.1±3.4) m 2 /g, leading to a calculated (assuming spherical particles) mean particle size of 58 nm.
Fourier transformed infrared (FTIR) analyses of the samples showed a pattern indicative of HA with the presence of some acid phosphate (874 cm −1 , 1356 cm −1 , 1389 cm −1 ), absorbed water, and acetate (670 cm −1 , 1417 cm −1 , 1462 cm −1 , 1568 cm −1 ).
Elemental analysis showed that the materials had a carbon content of 5.79% mass fraction (5.79%) from acetate residue. Because calcium acetate is quite soluble and this may mask the true solubility of the nano HA, solubility measurements were not performed on this material.
The nano HA particles were used as seeds to determine whether the setting time of a calcium phosphate cement (CPC) could be reduced. Cement hardening or setting time was measured with a Gilmore needle apparatus using a heavy Gilmore needle (453.5 g load, 1.06 mm diameter). The sample was considered set when the needle fails to leave a visible indentation when placed over the surface of the cement. Two CPC mixtures were prepared. The control CPC consisted of equimolar amounts of TTCP (72.9%) and DCPA (27.1%), and the experimental CPC was a mixture that consisted of 95% control CPC and 5% nano HA seeds. The setting times of the control and experimental CPCs were 30±1 min (n=2) and 12±1 min, respectively. These results showed that the nano HA produced dramatic effects on the TTPC+DCPA cement setting times. Because of the similarities in setting reaction mechanism, the nano particles of calcium phosphate materials are expected to produce similar effects on setting times of CPCs of different compositions.
Properties of Nano HA Prepared from a Carbonic Acid-HA Solution.
The sample was a white powder. XRD patterns showed that the material was amorphous ( FIG. 6 ). TEM observations showed clusters of porous spherical amorphous that arrange from 50 nm to about 1 μm in size ( FIG. 4 ). BET analysis showed surface area of (7.17±0.19) m 2 /g (n=2), leading to a calculated particle mean size of 266 nm. Because the material has the stoichiometry similar to that of HA but is amorphous under both XRD and TEM examinations, this material will be referred to as “amorphous HA” (AHA).
FTIR showed the pattern of amorphous calcium phosphate with the presence of some acid phosphate (870 cm −1 ), adsorbed water (3407 cm −1 ), molecular water (16435 cm −1 ), and a large amount of trapped CO 2 (2342 cm −1 ) as well as some carbonate incorporation in the structure (870 cm −1 , 1422 cm −1 , and 1499 cm −1 ). Elemental carbon analysis showed the material also contained 9.1 percent mass fraction (9.1%) of carbon.
Solubility experiments were conducted by dissolving the nano HA in a solution presaturated with well crystalline HA. The HA-presaturated solution was prepared by equilibrating crystalline HA in a 0.92 mmol/L phosphoric acid solution that also contained 150 mmol/L KNO 3 as an electrolyte background until saturation followed by filtration. The solution had [CA] and [P] concentrations of 0.75 mmol/L and 1.22 mmol/L, respectively, and a pH of 6.07. Dissolution experiment results showed that both the [Ca] and [P] concentrations as well as the pH increased rapidly with time ( FIG. 7 ). This indicated that the nano-HA was much more soluble than the crystalline HA> The calculated pIAP(HA) value for the nano HA was (mean±standard deviation; n=2) 93.5±0.3, which is significantly less positive (indicating greater solubility) than the value of 117 for macro scale HA.
Thermal gravimetric analysis (TGA) showed that sample mass losses occurred at (60 to 120)° C., (210 to 380)° C., (440 to 580)° C. and (650 to 750)° C. Most of the trapped CO 2 was lost after being held for one hour in vacuum at 600° C. ( FIG. 6 c ) and completely escaped after heating to 950° C. ( FIG. 6 d ). The intensity of the carbonate bands in AHA (870 cm −1 , 1422 cm −1 , 1422 cm −1 , and 1499 cm −1 ) decreased with increasing temperature ( FIGS. 6 a - c ) and finally changed to type B (870 cm −1 , 1457 cm −1 , and 1552 cm −1 ) and type A (870 cm −1 , 1457 cm −1 , and 1421 cm −1 ) carbonate incorporation, substituting for phosphate and hydroxyl groups, respectively, as the AHA structure transformed to a carbonated HA after heating to 950° C. in vacuum.
The solubility results showed that in each dissolution experiment, the [Ca] and [P] concentrations as well as the pH increased rapidly with time. This indicated that the nano-HA was much more soluble than the crystalline HA. For dissolution experiments conducted with pH 5.0 and pH 5.5 HA-presaturated solutions, rapid increases in [Ca] and [P] were followed by gradual decreases in these concentrations starting at about 2 min., while the pH continued to increase. This observation suggested that a less soluble HA phase began to precipitate as the nano HA continued to dissolve. The calculated PiAP(HA)=−log [IAP(HA)] (see Eq. (1) for IAP definition) values were (mean±standard deviation; n=2) 99.7±0.2, 97.2±0.4 and 93.5±0.3, respectively, for data obtained from dissolution experiments with HA-presaturated solutions having pH 5.0, 5.5 and 6.0. The smaller IAP values (more positive pIAP values), observed at the lower pHs probably was, in part, a result of the simultaneous dissolution-precipitation phenomenon.
More specifically, HA prepared from carbonic acid would likely be more soluble than crystalline HA, both because of its small particle size and CO 2 content. An IAP(HA) value as high as 3.3×10 −94 (pIAP=93.6), compared to 1×10 −117 for crystalline HA, was obtained from experiments in which the nano HA was dissolved in the pH 6 HA-presaturated solution. In this dissolution run, the [Ca] concentration increased from the initial value of (0.75±0.01) mmol/L in the crystalline HA-presaturated solution to a near a plateau value of (4.5±0.2) mmol/L at 10 min when the experiment ended. The [P] concentration similarly increased from the initial value of (1.2±0.1) mmol/L to a stable value of (3.5±0.2) mmol/L at 5 min. The pH of the solution continued to increase and reached 7.03±0.01 at 10 min. Dissolution of the same nano HA into the pH 5 HA-presaturated solution led to initial increases in [Ca] and [P] concentrations as in the pH 6 experiment. However, the initial increases were followed by continued decreases in these concentrations beginning at about 2 min to levels that were below the starting [Ca] and [P] concentrations. These results suggested that addition of nano HA to a pH 5 HA-saturaed solution led to sustained precipitation of crystalline HA. Such a process might be useful for remineralizing dental carious lesions or for occluding open dentinal tubules as a treatment for dental hypersensitivity.
Both nano HA samples, prepared with acetic acid and carbonic acid, appeared amorphous in SRD, but the former HA was crystalline as revealed by high resolution TEM despite the extremely small particle sizes of 5 nm to 10 nm. It is noted that this sample for the high resolution TEM analysis was suspended in ethanol for 2 days and there is a possibility that a phase transformation may have occurred during this period. However, under similar sample handle conditions, the carbonic acid derived nano HA remained amorphous under TEM analysis. Because the acetic acid- and carbonic acid-HA solutions had identical [CA] and [P] concentrations and the spray drying processing conditions were essentially the same, the differences in crystallinity of the nano HA samples prepared from the two solutions may be attributable to factors related to the nature of the acids.
Process Comparison
As described above, by using a minimal amount of a volatile weak acid to prepare the spray drying solutions, the process is capable of producing HA materials that contain little or no impurity components. In practice, a fair amount of acetate was found in the nano HA sample prepared with the acetic acid-HA saturated spray drying solution, and a large amount of trapped CO 2 was present in the nano HA prepared with the carbonic acid-HA saturated solution. The amount of residual acid components in the spray dried product could be reduced by using a more dilute solution, i.e., with lower [Ca] and [P] concentrations, because a smaller amount of acid would be required to prepare the solution. A complication with HA preparation in general is that HA has a high “affinity” for carbonate. Carbonate is readily incorporated into the HA structure in conventional HA preparation processes unless measures are taken to exclude CO 2 from the system. Because HA is the most alkaline salt among all calcium phosphates that can be prepared in an aqueous system, a larger amount of acid is needed to prepare HA saturated solutions compared to saturated solutions of the other calcium phosphates. Consequently, the residual acid problem is most pronounced in the HA preparation. Preliminary data indicates that no residual acid was present in dicalcium phosphate dihydrate nano particles prepared by this process. These observations indicate that the spray drying technique should be useful for preparing nano particles of a range of calcium phosphate phases with minimum impurities.
Multiple Nozzle Techniques
Many compounds of significant biomedical of industrial interests have low solubilities under all pH conditions. As a result, the spray drying technique described above using a one liquid nozzle is not useful because it is impossible to prepare a solution that contains a significant amount of dissolved mass of the salt. Availability of a two liquid nozzle makes it possible to prepared nano particles of these compounds because the cationic and anionic components of the salt are present in separate solutions that are combined only at the time of spraying. Nozzles that can simultaneously spray than two liquids can be constructed following the same principle as that for the single liquid nozzle. Thus, the spray drying process described here can be used for multi-liquid systems when needed to keep incompatible components in separate liquids, which are mixed at the time of atomization and spray drying.
Materials
The compositions of the solutions to be spray dried for preparing nano particles of several compounds are given in Table 3. It is noted that in some cases, such as in the preparation of F-substituted apatites, solution 1 will contain (Ca(OH) 2 and solution 2 will contain H 3 PO 4 and HF. Upon mixing and spray drying the two solutions, only water needs to be evaporated to produce FA or a F-substituted apatite. In other cases, an acid (or a base) is needed to solubilize the cationic (or anionic) component, and the acid will also need to be evaporated during the spray drying process. An example for this is the preparation of calcium silicate hydrate (CSH). Because SiO 2 is insoluble in acid but is slightly soluble in concentrated alkaline, amorphous SiO 2 is dissolved in a NH 4 OH solution, and NH 3 will be evaporated together with water during the spray drying process.
TABLE 3 COMPOSITIONS OF SPRAY DRYING SOLUTIONS FOR USE IN THE TWO-LIQUID NOZZLE PROCESS For Calcium Phosphate Preparation Solution 1 Ca(OH) 2 1 to 15 mmol/L Solution 2 H 3 PO 4 [P] = (0.5 to 2) × [Ca] Example of reaction: 5 Ca(OH) 2 + 3 H 3 PO 4 → Ca 5 (PO 4 ) 3 OH + 9 H 2 O ↑ For FA Preparation Solution 1 mmol/L Ca(OH) 2 1 to 15 mmol/L Solution 2 H 3 PO 4 + HF [P] = ⅗ × [Ca]; [F] = ( 1/500 to ⅕) × [Ca] Example of reaction: 5 Ca(OH) 2 + 3 H 3 PO 4 + HF → Ca 5 (PO 4 ) 3 F + 10 H 2 O ↑ For CaF 2 Preparation Solution 1 Ca(OH) 2 1 to 15 mmol/L Solution 2 NH 4 F [F] = 2 × [Ca] Example of reaction: Ca(OH) 2 + NH 4 F → CaF 2 + NH 3 ↑ + H 2 O ↑
Two Nozzle Methods
The spray drying apparatus ( FIG. 1 ) described for one-liquid spray drying process is used except that a 2-liquid nozzle (ViscoMist™ Air Atomizing Spray Nozzle, Lechler Inc., St. Charles, Ill.) is employed. This nozzle will simultaneously atomize two liquids that are mixed at the moment of atomization.
Results of Example of Two Nozzle Spray Method
Nano particles of CaF 2 was prepared by spray drying a 10 mmol/L Ca(OH) 2 solution and a 20 mmol/L ammonium fluoride (NH 4 F) solution that were combined at the time of atomization. XRD analysis ( FIG. 8 ) showed crystalline CaF 2 despite that the particles are submicron in size.
Preparation and Properties of Nano Calcium Fluroide, CaF 2 , Particles Using a Spray Drying Method Employing a 2-Liquid Nozzle
A 2 mmol/L Ca(OH) 2 solution and a 4 mmol/L ammonium fluoride (NH 4 F) solution were atomized and spray dried. Mixing of the Ca(OH) 2 and NH 4 F) solutions led to formation of CaF 2 and NH 4 OH; the latter was removed as NH 3 gas in the drying process. The CaF 2 nano particles were collected by the electrostatic precipitator as described before. XRD analysis showed crystalline CaF 2 with trace amount of DCPD also present due to contaminations from the precipitator plates. SEM examinations indicated that particles ranged from <50 nm to about 500 nm in size. The larger particles exhibited numerous spherical protuberances on the surfaces, suggesting that they were formed during the spray drying process through fusion of the much smaller particles. This suggests that well dispersed small particles could be produced by using a much lower spray rate. Chemical reactivity of the nano CaF 2 was evaluated by stirring (300 rpm) 33 mg of the nano CaF 2 in a 30 mL of a solution pre-saturated with crystalline CaF 2 . Specific ion electrodes for Ca and F and a combination pH electrode monitored the changes in [Ca] and [F] concentrations and pH. The results showed that both the [Ca] and [F] concentrations increased nearly by a factor of 2 and the solubility product (Ksp_ of the nano CaF2 was (2.3±0.2)×10 −10 which is about 6 times greater than the Ksp of value of 3.9×10 −11 for crystalline CaF 2 . These results indicated that the nano CaF 2 is significantly more reactive than macro CaF 2 .
In another test, mixtures containing a macro (median size 1.6 μm) DCPD and either the nano CaF 2 or a macro CaF 2 were mixed with water (1 g/1 mL) and the pastes were left in 100% humidity at 37° C. for 24 h. XRD patterns showed that there was no reduction in the amount of the macro CaF 2 whereas the nano CaF 2 was partially consumed by reacting with the DCPD forming a larger amount of apatitic product. DCPD was nearly completely consumed in either mixture. These results showed the nano CaF 2 was more reactive than the macro CaF 2 . It also indicated that the nano CaF 2 was not as reactive as the macro DCPD, suggesting that it would be necessary to use even smaller nano CaF 2 particles in order to have the CaF 2 dissolve in time for the reaction.
A Filter Paper Model for Evaluation of Fluoride Deposition by a Nano CaF2 Prepared by the Spray Drying Method
The ability of the nano CaF2 to be attached to tooth and other oral substrate surfaces was evaluated in vitro using a filter disc model. Five filter discs (Millipore, Bedford, Mass.) with a pore size of 0.2 μm and pore volume of 75% were placed in 20 mL of a nano CaF 2− water suspension or a NaF solution (250 ppm total F in either case). After 1 min of exposure, the filters were rinsed twice in 50 mL of a solution saturated with respect to CaF 2 to remove particles that were not firmly attached on/in the disc or remove unreacted F ions. Firmly fixed CaF 2 particles would not be lost to the washing solution by dissolution because the solution was presaturated with respect to CaF 2 . The F content in each disc was them determined by a F ion selective electrode method. F deposition on samples immersed in the nano CaF 2 suspension was 2.3±0.3 μg/cm2 of surface area (n=5) which was significantly 9p<0.001) greater than that (0.31±0.06 μg/cm2) produced by the NaF solution. These results showed that the nano CaF 2 particles were able to penetrate into the pores and fixed onto the substrate. Previous studies have shown a good correlation between the F deposition on the filter disc substrate and that on sound enamel. Thus, the results suggest that the nano CaF 2 suspension should be more effective than the currently used NaF solution for increasing oral F level.
Effect of a Nano CaF 2 Oral Rinse on Salivary F Levels
This study evaluated the effects of an oral rinse with the nano CaF 2− water suspension used in the above experiment on salivary F levels. Five subjects (1 hour without food or drink) rinsed for 1 min 20 mL of a nano CaF 2− water suspension (10.3 mg CaF 2 in 20 mL, 250 ppm total F) or a control F rinse (250 ppm F from NaF) and expectorated the rinse. Saliva sample was collected 1 hour post rinse and analyzed for F significantly (p=0.004, a log-transformation was performed to obtain normally distributed samples) higher F level (158 μg/mL) compared to that produced by the control rinse (36 μg/mL). This observation suggests that the nano CaF 2 rinse should be significantly more effective than the currently used F regimens. Because the nano CaF 2 material used in this study had a wide range of particle sizes (from <50 nm to about 500 nm), it is likely that an even more effective rinse could be developed by using nano CaF 2 with an optimal particle size distribution.
Summary of Factors Affecting Methods of Particle Formation
The methods disclosed in the invention are useful for preparing nano particles of any compound that can be formed by precipitation from an aqueous solution. The temperature under which the spray during process occurs is controllable by controlling the inlet air temperature and the temperature of the column ( FIG. 1 ). Air temperature in the range from −185° C. to 800° C. can be obtained using commercially available equipment. Similarly, a wide range of the column temperatures can be readily obtained using commercially available equipment. The wide range of temperatures facilitates preparation of materials that would form most readily at different temperatures.
The inventive method is suitable for preparing particles from 1 nm to 100 μm in size. The particle size can be controlled by (1) the concentration of the compound in the solution to be spray dried, (2) size of the atomized droplets, i.e., nozzle design. Droplet size is preferably less than the final particle size and thus less than about 100 μm. Chamber design is also a factor. The chamber is generally designed to minimize collection of condensate i.e., liquid from on the chamber walls.
The nature and composition of the compound that will be formed will depend on the solution composition. In many cases, the solution pH is the most important factor because, for calcium phosphates and other compounds that are salts of weak acids, it is the pH that determines the solid phase that would precipitate as the water evaporates from the solution.
The purity of the compound prepared, i.e., being free from undesired components, is dependent on the ability of spray drying process to remove the acid or base used to dissolve the compound in the spray drying solution. The acid/base must be a weak acid/base so that a substantial portion of the acid/base is in undissociated form, and the acid/base is almost totally undissociated as the last portion of the liquid is evaporated. The undissociated acid/base must also be sufficiently volatile to facilitate evaporation of the acid/base.
The nano particles prepared by the methods disclosed in the invention are useful in any application in which the compound is currently useful but a performance advantage can be gained by having a higher reactivity and/or smaller particle size. Examples of this include (1) accelerated hardening of calcium phosphate cements when one or more calcium phosphate nano particles are included in the ingredients, (2) accelerated hardening of mineral trioxide aggregate (MTA) when one or more calcium silicate nano particles are included in the ingredients, (3) desensitization of teeth by effective obturation of exposed dentin tubule opening with calcium phosphate nano particles, (4) deposition of fluoride in/on oral tissue by application of agents that contain calcium fluoride or other fluoride nano particles. (5) as a source of calcium, phosphate, or fluoride in remineralizing dentifrices, gels, rinses, chewing gums, and candies; and (6) as a source of calcium, phosphate, or fluoride for formulating scaffolds for bone defects repair.
Thus, examples of compounds of biomedical interests that can be prepared by the spray drying method:
(1) The calcium phosphate and other compounds named in Tables 1, 2 and 3.
(2) Calcium containing compounds that may be used as a source of calcium for remineralization of teeth or for formulation of scaffolds for bone defects repair. Examples are calcium lactate, calcium gluconate, calcium glycerophosphate, calcium acetate, calcium fumarate, calcium citrate, calcium malate, calcium chloride, calcium hydroxide, calcium oxide, calcium carbonate.
(3) Phosphate containing compounds that may be used as a source of phosphate for reminerlization of teeth or for formulation of scaffolds for bone defects repair.
Examples are the monobasic, dibasic and tribasic phosphate salts of sodium, potassium, and ammonium.
(4) Fluoride containing compounds that may be used as a source of fluoride for remineralization of teeth or for formulation of scaffolds for bone defects repair. Examples are sodium fluoride, potassium fluoride, fluorophosphates fluosilicate, flurortitanate, and fluorostannate salts of ammonium, sodium, potassium and calcium.
While various techniques and apparatus have been described with particularity the invention is subject to variations and this is to be limited only by the following claims and equivalents thereof.
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Nano-particles of calcium and phosphorous compounds are made in a highly pure generally amorphous state by spray drying a weak acid solution of said compound and evaporating the liquid from the atomized spray in a heated column followed by collection of the precipitated particles. Hydroxy apetite (HA) particles formed by such apparatus and methods are examples of particle manufacture useful in bone and dental therapies.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a multi-part closure for assembly on the neck of a container, the closure involving an axially shiftable valve element which is movable between open and closed positions to permit selective dispensing of the product contained in the container. More specifically, the invention relates to a unitary molded article from which all parts of the multi-part closure may be assembled in proper relationship on the neck of a filled container during the normal closure applying operation.
2. Description of the Prior Art
There are a large number of prior art patents which disclose dispensing closures involving two or more separate parts, one of which is securable to the neck of a container, and at least one of the other parts is relatively movable with respect to the secured part to open and close a dispensing opening in the container to permit dispensing of the contents of the container.
It has been the practice heretofore to separately form each of the molded parts of the multi-part container by separate injecting molding operations, then assemble the multi-part container into a unitary structure and then, lastly, apply the preassembled closure to the neck of a filled container. Separate molding operations for each part of the multi-part closure, followed by assembly operations, are inherently expensive, and there is, accordingly, a need for a multipart closure which may be molded as a unitary article and assembled in proper functioning relationship during the normal application of the closure to a filled container by a conventional capping machine.
SUMMARY OF THE INVENTION
In accordance with the method of this invention, all parts of a multi-part dispensing closure for a container neck are concurrently molded in a single molding cavity from an elastomeric plastic material. The resulting article comprises a cap-shaped bottom element having a central sleeve in its panel portion defining a valve receiving dispensing opening. The one or more valve parts which cooperate with the dispensing opening are concurrently molded in an axially spaced, concentric relationship to the dispensing opening and connected to the cap portion of the dispensing closure by a thin annular web of the plastic material. If more than one valve component is required, the second valve component is similarly molded in axially spaced, concentric relationship to the first valve component and connected to the first valve component by a thin annular web of the plastic material.
The assembly of the molded parts into an operable dispensing closure is accomplished during the application of the cap portion of the closure to the neck of container. After such cap portion is applied to the neck threads, or otherwise secured to the neck by a conventional capping machine, an axial downward force is applied to the upwardly projecting valve components, which force is effective to sever the thin annular web connecting such valve components to the cap portion, and to move the valve components downwardly into their proper assembled relationship relative to the valve receiving dispensing opening in the cap portion.
Accordingly, it is an object of this invention to provide a less expensive method of fabricating and assembling a multi-part dispensing closure of the type that is formed by injection molding of elastomeric plastic materials.
A further object of this invention is to provide a unitary molded article having a container neck engaging portion at one end thereof which can be assembled into a fully operative dispensing closure through the application of an axial force to the top portions of the molded article.
Further objects and advantages of the invention will be readily apparent to those skilled in the art from the following detailed description, taken in conjunction with the annexed sheets of drawings, on which are shown several preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical sectional view of a unitary molded plastic article embodying this invention;
FIG. 2 is a sectional view of the plastic article of FIG. 1 after assembly onto the neck of a container and severing of the web connection between the closure portion and valve portion of the plastic article, the valve portion being shown in its closed position;
FIG. 3 is a view similar to FIG. 2 but with the valve portion of the dispensing closure shown in its open position;
FIG. 4 is a vertical sectional view of a modified form of dispensing closure, showing the closure in its condition as originally molded;
FIG. 5 is a reduced scale vertical sectional view showing the dispensing closure of FIG. 4 assembled to the neck of a container after severance of the web connecting the closure portion of the dispensing closure to the valve portion, the valve portion being shown in its closed position;
FIG. 6 is a view similar to FIG. 5 showing the valve portion of the dispensing closure in its open position;
FIG. 7 is a vertical sectional view of a three-part dispensing closure in its, as molded, configuration;
FIG. 8 is a vertical sectional view showing the dispensing closure of FIG. 7 assembled to the neck of a container and with the webs connecting the various valve elements severed and the valve elements positioned in their closed position;
FIG. 9 is a view similar to FIG. 8 but illustrating the valve elements in their opened position;
FIG. 10 is a schematic sectional view of a closure applicating head of a conventional closure applying machine showing the modification thereof to carry out the method of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For simplicity of understanding the principles of this invention, the various embodiments of dispensing closures will be first described in their fully assembled operative relationship on a container and then described in their "as molded" form when fabricated in accordance with this invention. Referring, therefore, to FIGS. 2 and 3, a dispensing closure 8 fabricated and assembled in accordance with this invention includes a cap part 10 having a panel portion 10a and a depending peripheral skirt portion 11 having internal threads 11a for securement to threads 2a provided on the neck portion 2 of a product filled container. It will be understood by those skilled in the art that the method of securely applying the cap portion 10 of the dispensing closure 8 to the neck 2 of the container forms no part of this invention, and a snap bead type of securement could be substituted for the threaded securement illustrated in the drawings. The central portion of cap 10 is formed as a vertically extending sleeve 12 defining a central axial bore 12a. Sleeve 12 is provided at its upper portions with an inwardly projecting shoulder 12b to function both as a resilient latch for retaining valve element 15 in its closed position and a stop preventing the inadvertent removal of a valve element 15 from bore 12a.
The valve element 15 is of sleeve like configuration having a closed upper end portion 15a having a radially projecting flange 15b permitting the top end of the valve 15 to be readily grasped by the fingers to be pulled upwardly to an open position. The sleeve portion 15c of valve 15 is snugly slidable within the bore defined by the internally projecting shoulder 12a. Sleeve portion 15c is provided with a pair of axially spaced, annular external ribs 15d and 15e which resiliently cooperate with the internally projecting shoulder 12a of sleeve 12 to position the valve in either its closed position as shown in FIG. 2, or in its fully opened position as shown in FIG. 3. In either event, the ribs 15d and 15e are distortable through the application of a sufficient axial force to radially compress and pass through the bore of the inwardly projecting shoulder 12a. Shoulder 12a, being fabricated of the same elastomeric type thermoplastic material is likewise expandable to facilitate such passage.
The valve 15 defines a central bore 15f communicating with the interior of the container and, hence, permitting the product contained in the container to readily pass into such bore. A radially disposed dispensing opening 15g is provided in the side wall of sleeve portion 15c. When the valve 15 is pushed axially downwardly to the limit permitted by the radially projecting top flange 15b, it will be apparent that the closure is in its sealed position and no product can escape therefrom. On the other hand, when the valve 15 is grasped by the fingers and pulled upwardly to the position indicated in FIG. 3, the radial dispensing port 15g is exposed and the contents of the container can readily be dispensed through such opening.
The method of fabricating and assembling the dispensing closure 8 shown in FIGS. 2 and 3, will now be described. First, the cap portion 10 and the valve portion 12 of the dispensing closure 8 are integrally molded in the same cavity by virtue of providing a connecting cavity defining a thin annular web portion 16 by which the valve element 15 is integrally connected to the cap portion 10 in an axially spaced, but coaxial relationship to such cap portion. The container is then filled with product in any conventional filling machine and the combined unitary cap and valve portions 10 and 15 are assembled to the container in a conventional closure applicating machine.
As shown schematically in FIG. 10, closure applicating machines generally utilize a capping head 100 which is configured to engage the external periphery of the cap to be applied to the container. Such capping head is normally mounted on the bottom of a hollow shaft 101 which is moved axially and rotated by the machine elements in order to effect the rotational threading of cap portion 10 carried onto the threaded neck of a bottle. In accordance with this invention, a plunger 102 is appropriately slidably mounted within the bore of the hollow shaft 101 and is shifted downwardly by either a fluid operated piston (not shown) or by a camming mechanism riding on the circular camming rails normally provided in such capping machines so as to impart an axially downward force to the valve portion 15 immediately after the cap portion 10 of the dispensing closure 8 has been applied to the container neck. Such axial force will effect a severing of the web 16 which interconnects the cap portion 10 and the valve portion 15 and permits the valve 15 to be moved downwardly sufficiently to cause both the annular shoulders 15e and 15d to successively pass through the internally projecting shoulder 12a defined by the cap sleeve 12 and thus position the valve 15 in its closed position relative to the container, as shown in FIG. 2.
Referring now to FIGS. 4 through 6, there is shown a modified form of two-piece dispensing closure which may be fabricated and assembled in accordance with this invention. Referring first to FIGS. 5 and 6, the dispensing closure 20 is shown in assembled relationship to the threaded neck 2 of a filled container 1, with the dispensing closure being shown in its closed position in FIG. 5, and in its opened position in FIG. 6.
The dispensing closure 20 includes a cap-shaped portion 21 having a panel portion 21a and a depending peripheral flange portion 21b defining internal threads 21c for cooperation with the container neck threads 2a. An integral vertical sleeve 22 is formed in the center of panel portion 21a and defines an axially extending bore 22a. The lower portions of sleeve 22 are formed as arcuately inwardly projecting portions 22b which function to achieve a seal with the bottom end 25c of the valve element 25 in the manner which will be hereinafter described. The top end of sleeve 22 defines an internally projecting annular shoulder 22d which functions as a resilient stop for upward movements of the valve element 25.
Valve element 25 is in the form of a plunger having a medial portion 25a slidably engaged by the bore of the internally projecting shoulder 22a of sleeve 22. The uppermost portion of plunger 25 is flared outwardly as indicated at 25b to provide a convenient grasping surface for the fingers to permit the valve 25 to be pulled upwardly to its opened position. The bottom portions of valve 25 are of reduced diameter as indicated at 25c and slidably and sealingly cooperate with the internally projecting portions 22b of the cap sleeve 22.
An external annular rib 25d is provided in the center of the plunger 25 to cooperate with the internally projecting flange 22d to resiliently hold the plunger 25 within the bore of the sleeve 22. Because of the elastomeric nature of the materials from which the cap portion 21 and the valve portion 25 are concurrently molded, the shoulder 25d will readily pass through the constriction provided by the bore of the internally projecting shoulder 22d through the application of a modest downward axial force.
The valve 25 is in its closed position when it is pushed downwardly sufficiently to engage the reduced diameter portion 25c with the inwardly converging portions 22d of the cap sleeve 22, as shown in FIG. 5. It is shiftable to its opened position by pulling it axially upwardly until the shoulder 25d engages the bottom face of the internally projecting sleeve shoulder 22d, as shown in FIG. 6. In this position, the product contents of the container can flow around the bottom end of the valve plunger 25 and then inwardly through one or more radial ports 25e provided in the wall of plunger 25 which communicate with a central dispensing bore 25f. Thus the product contents of the container may be readily dispensed through valve 25 when it is positioned in its opened position as illustrated in FIG. 6.
Referring now to FIG. 4, the dispensing valve 20 is shown in its "as molded" position wherein the valve plunger 25 and the cap portion 21 are concurrently molded in the same cavity and are interconnected by a thin annular web 26.
As in the previous modification, the cap portion 21 is assembled to the neck of a filled container and then an axial force is immediately applied to the top of valve plunger 25 to cause a severing of the web 26 and permit the valve plunger 25 to move downwardly to its assembled, operative position relative to the cap sleeve 22.
Referring now to FIGS. 7-9, there is shown a still further embodiment of this invention wherein a three piece dispensing closure unit 30 is provided. Closure unit 30 comprises a cap portion 31 having a panel portion 31a and a depending peripheral skirt portion 31b provided with internal threads 31c for engagement with the container neck threads 2a. Cap portion 31 is further provided with a central sleeve portion 32 which defines an open bore 32a within which a two-piece valve element is mounted. An internally projecting shoulder 32b is formed at its upper end. One piece of such valve element comprises a plug portion 35 having a peripheral annular rib 35a cooperating with an internal annular recess 32c defined in the cap sleeve bore 32a. A plurality of upwardly extending fluid dispensing passages 35d are formed in the plug portion 35. The center of plug portion 35 is provided with an upstanding cylindrical plunger 35c upon which the second valve piece 38 is slidably mounted. The second valve piece 38 is of cup shaped configuration having a vertically extending bore 38a formed in its bottom portion and slidably receiving the plunger 35c therein in the closed position of the valve, as illustrated in FIG. 8. The top portions of the upper valve piece 38 are provided with an outwardly projecting shoulder 38b permitting convenient grasping by the fingers.
The side walls 38c of the upper valve part 38 slidably cooperate with the internal bore of the sleeve shoulder 32b. Adjacent the bottom end of the upper valve piece 38, an annular shoulder 38d is formed which provides a resilient stop for upward movement of the valve part 38 by engaging the underface of the internally projecting sleeve shoulder 32b. It will be readily apparent that when the upper valve piece 38 is pushed downwardly into the cap sleeve 32 so that the cylindrical projection 35c of the lower valve piece 35 engages the bore 38a, the closure is effectively sealed and no dispensing of the contents of the container can be accomplished. However, when the upper valve piece 38 is grasped by the fingers and raised to the position indicated in FIG. 9, the contents of the container can then flow through the vertical openings 35d provided in the lower valve piece 35 and thence through the now opened central bore 38a provided in the upper valve piece 38.
Referring now to FIG. 7, the dispensing closure 30 is fabricated by molding of an appropriate elastomeric plastic material in a single mold cavity. The lower valve piece 35 is integrally connected to the top end of the sleeve portion 32 of the cap 31 by a thin web 37. Similarly, the top end of the projection 35c of the lower valve piece 35 is connected by a thin annular web 39 to the bottom end of the upper valve piece 38. It will be noted that the resulting unitary article has all of the separate components thereof disposed in axially spaced, yet concentric relationship.
Accordingly, when the cap portion 31 is assembled to the neck of a container and an axial downward force is then applied to the top of the upper valve piece 38, the thin webs 37 and 39 will be severed and the valve components 38 and 35 will be moved axially downwardly into their assembled relationship within the cap sleeve 32 as illustrated in FIG. 8. It is preferred that the web 37 be made somewhat thinner than the web 39 so that this web severs first and permits the lower valve portion 35 to be inserted in the bore 32a of the cap sleeve 32 prior to severing of the connecting web 39. While this sequential severing of the webs is desirable, it is not necessary for the reliable assemblage of the dispensing closure 30 from the unitarily fabricated components shown in their "as molded" relationship in FIG. 7.
Further modifications and applications of the principles of this invention will be readily apparent to those skilled in the art. It is therefore intended that the scope of the invention be determined solely by the appended claims.
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The disclosure relates to a unitary molded article and a method for producing a multi-part closure for assembly on the neck of a container, the closure involving an axially shiftable valve element which is movable between open and closed position. All parts of the multi-part valve element are integrally molded in a common molding cavity and the various relatively movable parts are interconnected by thin annular webs which are severed and the parts placed in proper operative condition during the assembly of the closure to the neck of a container by a conventional applicating machine.
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FIELD OF TECHNOLOGY
[0001] The following relates to a washing machine, and more particularly, to a method for warning of a residual amount of liquid detergent by determining the residual amount of liquid detergent based on a value calculated by adding up amounts of liquid detergent used for washing processes.
BACKGROUND
[0002] In general, a washing machine refers to a product that removes pollutants of clothes and bedclothes through emulsification of a detergent, friction of water flow caused by rotations of a pulsator, and impact applied by the pulsator.
[0003] The washing machine is divided into a top-loading type in which a washing tub is erected and a drum type in which a washing tub is laid, depending on the shape of the washing tub in which laundry is housed.
[0004] When a container of a washing machine is filled up with a liquid detergent easy to dilute and having an excellent emulsification function and a washing command is inputted, the washing machine supplies a preset amount of liquid detergent, and then automatically performs a series of processes including a washing process, a rinsing process, and a spin-drying process.
[0005] As a related art of the present invention, Korean Patent Laid-open Publication No. 10-2010-0081214 published on Jul. 14, 2010, has disclosed a washing machine and a sensing method for liquid detergent supply.
[0006] Since the conventional washing machine automatically supplies a liquid detergent during a washing process, a user must previously store the liquid detergent in the container before the washing process such that the washing machine does not lack the liquid detergent.
[0007] Therefore, the user must frequently check the residual amount of liquid detergent stored in the container, whenever using the washing machine.
[0008] Furthermore, since the conventional washing machine includes a plurality of sensors for sensing the residual amount of liquid detergent, the manufacturing cost increases, and a current flowing through the sensors may leak to the container. In this case, the user may get an electric shock.
SUMMARY
[0009] The present disclosure is conceived to solve such problems of the related art, and an aspect is to provide a method for warning of a residual amount of liquid detergent, which calculates a total use amount by adding up amounts of liquid detergent used for washing processes, determines a residual amount of liquid detergent based on the calculated total use amount, and warns of the residual amount depending on the determination result.
[0010] Another aspect is to provide a method for warning of a residual amount of liquid detergent, which automatically warns a residual amount of liquid detergent stored in a container such that a user does not need to frequently check the residual amount of liquid detergent and easily supplies liquid detergent.
[0011] According to another aspect, a method for warning of a residual amount of liquid detergent includes: calculating a total use amount of liquid detergent by adding up a use amount of liquid detergent whenever a washing process is performed; and comparing the total use amount of liquid detergent to a reference amount, and warning of a residual amount of liquid detergent according to the comparison result.
[0012] The warning of the residual amount of liquid detergent may include warning of the residual amount of liquid detergent when the total use amount of liquid detergent is equal to or more than the reference amount.
[0013] The use amount of liquid detergent may be set according to one or more of a washing course, a laundry amount, a liquid detergent control command, and a washing water amount.
[0014] The method may further include displaying the number of additional washing processes to be performed, after the warning of the residual amount of liquid detergent.
[0015] The number of additional washing processes to be performed is calculated by dividing the residual amount of liquid detergent by an average use amount of liquid detergent.
[0016] The average use amount of liquid detergent may be calculated by dividing the total use amount of liquid detergent by the number of performed washing processes.
[0017] The reference amount may be set according to an initial amount of liquid detergent when a container is filled up with the liquid detergent.
[0018] According to the embodiment of the invention, since a warning for a residual amount of liquid detergent is automatically issued, a user does not need to frequently check the residual amount of liquid detergent, and may easily fill up a container with the liquid detergent.
[0019] Furthermore, since a sensor for sensing the residual amount of liquid detergent is not installed, it is possible to reduce the manufacturing cost of the washing machine and to prevent a user from getting an electric shock from a current leaking to the container.
BRIEF DESCRIPTION
[0020] The above and other aspects, features and advantages of the invention will become apparent from the following detailed description in conjunction with the accompanying drawings, in which:
[0021] FIG. 1 is a block configuration diagram of a washing machine in accordance with an embodiment of the present invention;
[0022] FIG. 2 is a flowchart showing a method for warning of a residual amount of liquid detergent in accordance with the embodiment of the present invention;
[0023] FIG. 3 is a flowchart showing a process of controlling a use amount of liquid detergent in FIG. 2 ; and
[0024] FIG. 4 is a graph illustrating a reference amount and a warning time point in accordance with the embodiment of the present invention.
DETAILED DESCRIPTION
[0025] Embodiments of the invention will hereinafter be described in detail with reference to the accompanying drawings. It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or sizes of components for descriptive convenience and clarity only. Furthermore, the terms as used herein are defined by taking functions of the invention into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to the overall disclosures set forth herein.
[0026] A method for warning of a residual amount of liquid detergent is performed as follows: amounts of liquid detergent used for washing processes are added up to calculate a total use amount, the calculated total use amount is compared to a reference amount, and a warning for the residual amount of liquid detergent is issued according to the comparison result.
[0027] Here, the total use amount of liquid detergent is calculated by adding up the amount of liquid detergent used whenever a washing process is performed.
[0028] An amount of liquid detergent to be used (hereafter, referred to as use amount of liquid detergent) is preset according to the amount of laundry. However, the use amount of liquid detergent may be additionally set for each washing course selected by a user, directly set by the user, or set according to a washing water amount selected by the user.
[0029] After a warning for the residual amount of liquid detergent is issued, an average use amount of liquid detergent is calculated. Then, based on the calculated average use amount, the number of washing processes which can be additionally performed by the residual amount of liquid detergent is calculated and displayed.
[0030] FIG. 1 is a block configuration diagram of a washing machine in accordance with an embodiment of the present invention.
[0031] The washing machine in accordance with the embodiment of the present invention includes a key input unit 10 , a liquid detergent supply unit 30 , a laundry amount detection unit 40 , a washing device 50 , a warning unit 60 , a display unit 70 , and a control unit 80 .
[0032] The key input unit 10 is configured to receive various control commands from a user. The key input unit 10 includes a washing command input key 11 , a washing course select key 12 , a washing water control key 13 , a liquid detergent control key 14 , and an initial amount setting key 15 .
[0033] The washing command input key 11 is configured to input a washing command. The washing command selectively performs one or more of a washing process, a rinsing process, a spin-drying process, and a drying process or continuously performs a preset series of washing courses.
[0034] In this specification, a case in which a washing process using liquid detergent is performed when the washing command input key 11 is inputted will be taken as an example for description.
[0035] The washing course select key 12 is configured to input a washing course select command for selecting a washing course. The washing course may include a standard washing course in which a series of processes including a washing process, a rinsing process, and a spin-drying process are automatically performed. In addition, the washing course may include a lingerie washing course, a wool washing course, a sports shoes washing course and the like, depending on the type and material of the laundry.
[0036] The washing course is not limited to the above-described examples, but may be further subdivided into various washing courses. Therefore, the scope of the present invention may include all washing courses provided by the washing machine.
[0037] Meanwhile, the use amount of liquid detergent is set in various manners depending on the washing courses. Therefore, when a user inputs a washing course select command through the washing course select key 12 , the liquid detergent is supplied according to the use amount of liquid detergent, which is set in the selected washing course.
[0038] For reference, a washing water amount is preset for each of the washing courses. Therefore, the washing water amount set for the selected washing course is supplied to perform a washing process. However, the washing water amount may be separately controlled.
[0039] The washing water control key 13 is configured to input a washing water control command for controlling the washing water amount. Through the washing water control key 13 , a user may arbitrarily control the washing water amount. Furthermore, although a washing course is selected to set a washing water amount, the washing water amount may be additionally controlled.
[0040] Here, the washing water amount may be set is various manners such as large amount, medium amount, and small amount.
[0041] The liquid detergent control key 14 is configured to input a liquid detergent control command for controlling the amount of liquid detergent used in the washing process. Through the liquid detergent control key 14 , the user may arbitrarily control the use amount of liquid detergent. Furthermore, although a washing course is selected to set the use amount of liquid detergent, the use amount of liquid detergent may be additionally controlled.
[0042] In this case, whenever the liquid detergent control key 14 is inputted once, the use amount of liquid detergent may be increased or decreased by a predetermined amount, or any one of a plurality of preset liquid detergent supply amounts may be selected, and the liquid detergent may be supplied by the selected amount.
[0043] The initial amount setting key 15 is configured to set an initial amount of liquid detergent supplied to a container (not illustrated), when the container is filled up with the liquid detergent.
[0044] The initial amount refers to an initial amount of liquid detergent supplied to the container by a user when the container is filled up with the liquid detergent, and is set by the user. The initial amount may include a plurality of initial amounts, and the user sets an initial amount corresponding to the amount of liquid detergent supplied by the user.
[0045] For example, when the container is filled up with liquid detergent, the initial amount is set to the highest amount, and when the container is filled with a smaller amount of liquid detergent than the highest amount, the initial amount may be set to the second highest amount.
[0046] Therefore, a separate sensor for sensing liquid detergent does not need to be provided.
[0047] The liquid detergent supply unit 30 opens or closes a valve (not illustrated) installed in the container, and supplies the liquid detergent stored in the container to a washing tub. In this case, the liquid detergent supply unit 30 supplies liquid detergent by a use amount set according to a laundry amount, or additionally supplies liquid detergent by a use amount set according to a washing course select command, a washing water control command, or a liquid detergent control command.
[0048] The washing device 50 includes a water supply device 51 , a drain device 52 , and a washing motor 53 .
[0049] The water supply device 51 supplies washing water to the washing tub (not illustrated). The water supply device 51 includes a water supply tube (not illustrated) and a water supply valve (not illustrated). The water supply tube has one side to a water supply unit (not illustrated) to supply cold water and hot water and the other end connected to the washing tub, thereby forming a flow path through which washing water supplied from the water supply unit is transferred to the washing tub. The water supply valve is installed in the water supply tube so as to control the washing water.
[0050] The drain device 52 includes a drain tube (not illustrated), a drain valve (not illustrated), and a drain pump (not illustrated). The drain tube has one side connected to the washing tub and the other side connected to communicate with the outside of the washing machine, thereby forming a flow path through which the washing water of the washing tub is drained to the outside of the washing machine. The drain valve is installed in the drain tube so as to control washing water. The drain pump forces washing water to be drained to the outside of the washing machine through the washing tube.
[0051] The washing motor 53 rotates the washing tub in a forward or backward direction to wash the laundry. Typically, a driving force generated by the washing motor 53 is transmitted to the washing tub through a power transmission device (not illustrated) including a gear or transmission belt.
[0052] The above-described washing device 50 is not limited to the washing device 51 , the drain device 52 , and the washing motor 53 , but may further include various devices such as a heater to heat washing water.
[0053] The warning unit 60 warns of the residual amount of liquid detergent. The warning unit 60 warns of the residual amount through a buzzer sound or a display (not illustrated) provided on a front panel of the washing machine.
[0054] The display unit 70 displays the number of additional washing processes to be performed. The display unit 70 is installed on the front panel of the washing machine such that a user may easily recognize the number of additional washing processes to be performed. The display unit 70 may include a light emitting diode (LED) or liquid crystal display (LCD).
[0055] Here, the number of additional washing processes to be performed indicates an expected number of washing processes which can be performed by the residual amount of liquid detergent, after the warning unit 60 warns of the residual amount of liquid detergent.
[0056] The control unit 80 calculates a total use amount by adding up the amounts of liquid detergent used for washing processes in a state where the initial amount is set, compares the calculated total use amount to the reference amount, and warns of the residual amount depending on the comparison result.
[0057] Here, the reference amount refers to an amount serving as a reference value for warning that the residual amount of liquid detergent is insufficient. The reference amount is set in such a manner that the amount of liquid detergent remaining in the container based on the initial amount is equal to or more than the amount of liquid detergent used for at least one washing process. That is, even after a warning is issued because the total use amount of liquid detergent is equal to or larger than the reference amount, a washing process may be additionally performed.
[0058] Therefore, when a user performs the next washing process, the user may not lack the liquid detergent. At this time, the user may be induced to fill up the container with the liquid detergent.
[0059] Hereafter, the method for warning of a residual amount of liquid detergent in accordance with the embodiment of the present invention will be described with reference to FIGS. 2 to 6 .
[0060] FIG. 2 is a flowchart showing the method for warning of a residual amount of liquid detergent in accordance with the embodiment of the present invention. FIG. 3 is a flowchart showing a process of controlling the use amount of liquid detergent in FIG. 2 . FIG. 4 is a graph illustrating the reference amount and a warning time point in accordance with the embodiment of the present invention.
[0061] Referring to FIG. 2 , an initial amount corresponding to the amount of liquid detergent supplied to the container is set through the initial amount setting key 15 , and a reference amount is set according to the initial amount, at step S 10 .
[0062] At this time, the reference amount is set in such a manner that the amount of liquid detergent remaining in the container based on the initial amount is equal to or more than the amount of liquid detergent used for at least one washing process.
[0063] In such a state where the reference amount is set, the amount of liquid detergent to be used during the washing process may be set at step S 100 .
[0064] The process of setting the use amount of liquid detergent will be described with reference to FIG. 3 .
[0065] First, when the washing course select key 12 is inputted at step S 101 , the use amount of liquid detergent is set according to the input washing course select command at step S 102 .
[0066] In this case, the use amount of liquid detergent is preset for each washing course. When a specific washing course is selected, the amount of liquid detergent to be used for the corresponding washing process is set to the preset amount of liquid detergent to be used for the corresponding washing course.
[0067] Meanwhile, when the liquid detergent control key 14 is inputted at step S 103 , the use amount of liquid detergent is set according to the input liquid detergent control command at step S 104 . In this case, the use amount of liquid detergent is increased or decreased according to the liquid detergent control command. The use amount of liquid detergent may be increased or decreased by a predetermined amount whenever the liquid detergent control key is inputted once, or may be set to any one of a large amount, a medium amount, and a small amount.
[0068] On the other hand, when the washing water amount control key is inputted at step S 105 , the use amount of liquid detergent is set according to the input washing water amount control key at step S 106 . In this case, the use amount of liquid detergent is increased or decreased depending on the washing water amount. As the washing water amount is increased, the use amount of liquid detergent is increased, and as the washing water amount is decreased, the use amount of liquid detergent is decreased.
[0069] Furthermore, although a washing course is selected, the use amount of liquid detergent which is set for the washing course may be additionally changed according to a liquid detergent control command, when the liquid detergent control command is inputted.
[0070] Furthermore, although a washing course is selected, the use amount of liquid detergent which is set for the washing course may be additionally changed according to a washing water control command, when a washing water control command is inputted.
[0071] Furthermore, although a washing course is selected, the use amount of liquid detergent which is set for the washing course may be additionally changed according to a liquid detergent control command and a washing water control command, when a liquid detergent control command and a washing water control command are inputted.
[0072] Therefore, a user may select a washing course, and then input the liquid detergent control key 14 and/or the washing water control key, thereby performing a washing process according to the washing course, a washing water amount, and the use amount of liquid detergent which are suitable for the user's taste.
[0073] As described above, after the use amount of liquid detergent is set, whether or not a washing command is inputted through the washing command input key 11 is checked at step S 140 .
[0074] When the washing command is inputted, the laundry amount is detected through the laundry amount detection unit 40 at step S 150 .
[0075] Here, when the laundry amount is detected, various data required for performing the selected washing course are set.
[0076] Then, according to the use amount of liquid detergent which was set at the use amount setting process S 100 , the liquid detergent is supplied at step S 160 .
[0077] Then, a washing process is performed by the washing device 50 . Here, since the process of performing a washing process using the washing device 50 may be easily understood by those skilled in the art, the detailed descriptions thereof are omitted herein.
[0078] Meanwhile, the control unit 80 calculates a total use amount of liquid detergent by adding up the supplied amounts of liquid detergent, at step S 170 .
[0079] When the total use amount of liquid detergent is calculated, the total use amount of liquid detergent is compared to the preset reference amount so as to determine whether the total use amount of liquid detergent is equal to or more than the reference amount, at step S 180 .
[0080] As a determination result, when the total use amount of liquid detergent is equal to or more than the reference amount, the control unit 80 controls the warning unit 60 to issue a warning for the residual amount of liquid detergent at step S 190 .
[0081] Meanwhile, when the total use amount of liquid detergent is less than the reference amount, whether or not to perform the next washing process is checked.
[0082] When the use amount of liquid detergent is not set at the use amount setting process S 100 , whether or not a washing command is inputted through the washing command input key 11 is checked at step S 110 .
[0083] When the washing command input key 11 is inputted, a laundry amount is detected through the laundry amount detection unit 40 at step S 120 , a washing water amount and a use amount of liquid detergent are set according to the detected laundry amount, and the set amount of liquid detergent is supplied by the liquid detergent supply unit 30 .
[0084] Then, the washing device 50 is controlled to perform a washing process.
[0085] Meanwhile, after the liquid detergent is supplied, the total use amount of supplied liquid detergent is calculated at step S 170 , and whether the total use amount of liquid detergent is equal to or more than the reference amount is determined at step S 180 . As a determination result, when the total use amount of liquid detergent is equal to or more than the reference amount, a warning for the residual amount of liquid detergent is issued by the warning unit 60 at step S 190 .
[0086] As such, after the warning is issued, the average use amount of liquid detergent is calculated by dividing the total use amount of liquid detergent by the number of performed washing processes at step S 200 .
[0087] When the average use amount of liquid detergent is calculated, the number of additional washing processes to be performed is calculated by dividing the residual amount of liquid detergent by the average use amount, and then displayed through the display unit 70 at step S 210 .
[0088] At this time, the residual amount of liquid detergent is set based on the initial amount when the reference amount is set.
[0089] Therefore, the number of washing process which can be performed by the amount of liquid detergent remaining in the container may be expected.
[0090] That is, as illustrated in FIG. 4 , when the total use amount is equal to or more than the reference amount lower than the initial amount, a warning is issued. However, it can be seen that the amount of liquid detergent remaining in the container corresponds to an amount of liquid detergent by which three additional washing processes can be performed.
[0091] Meanwhile, when and the user fills up the container with liquid detergent and inputs the initial amount setting key 15 after a warning for the residual amount of liquid detergent is issued by the warning unit 60 , the total use amount of liquid detergent and the average use amount which have been calculated so far are initialized, and a reference amount is reset according to the set initial amount.
[0092] Although some embodiments have been provided to illustrate the invention in conjunction with the drawings, it will be apparent to those skilled in the art that the embodiments are given by way of illustration only, and that various modifications and equivalent embodiments can be made without departing from the spirit and scope of the invention. The scope of the invention should be limited only by the accompanying claims.
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A method for warning of a residual amount of liquid detergent includes: calculating a total use amount of liquid detergent by adding up a use amount of liquid detergent whenever a washing process is performed; and comparing the total use amount of liquid detergent to a reference amount, and warning of a residual amount of liquid detergent according to the comparison result. Accordingly, a user does not need to frequently check the residual amount of liquid detergent, and may easily fill up a container with the liquid detergent. Furthermore, since a sensor for sensing the residual amount of liquid detergent is not installed, it is possible to reduce the manufacturing cost of the washing machine and to prevent a user from getting an electric shock from a current leaking to the container.
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The present application claims the benefit of U.S. Provisional Application Ser. No. 60/054,394 of Spear et al., filed Jul. 31, 1997.
The present invention relates to wagon assemblies, and, more particularly, to wagon assemblies of the stackable type.
Conventionally, a wagon has a rectangular body with four walls configured to carry items and materials therein. A set of wheels rollingly support the conventional wagon. A handle is typically provided so that the wagon can be rolled manually by pulling on the handle. It is also commonly known to rotatably mount the front wheels on an axle which is rotatably mounted to bottom of the wagon body. The handle is then mounted to the axle and the wagon can be steered by pulling the handle in a desired steering direction, thereby rotating the front axle and aligning the front wheels in that direction. The conventional wagon, however, presents a number of problems and shortcomings.
Conventional wagons cannot be stacked on top of one another in a nesting relation. Thus, in order to ship conventional wagons, a manufacturer has two options. First, the manufacturer may ship the conventional wagons fully assembled. However, shipment of fully assembled conventional wagons greatly increases the shipping costs. Second, the conventional wagons may be shipped disassembled. When the conventional wagons are shipped disassembled, however, either the retailer or the consumer must assemble the individual parts and components of the wagon. By placing the responsibility on the retailer or consumer to assemble the conventional wagon, there is a possibility that individual components or parts may become lost or damaged. Also, shipping the wagons unassembled provides opportunities for individual components to be lost or broken during the shipping process.
It is known, however, that stacking items on top of one another in a nesting relation reduces the amount of space needed to store those items. For example, U.S. patent application Ser. No. 08/724,688 discloses a hose cart assembly which is constructed to be stacked in a nesting relation with other hose cart assemblies. By stacking wagons on top of one another, the wagons can be shipped fully assembled at less cost than if they were shipped individually. Also, shipping the wagons fully assembled obviates the problems associated with having the consumer or the retailer assemble the wagons themselves.
Therefore, it is an object of the present invention to provide a wagon assembly which can be stacked in a nesting relation with other wagon assemblies. The present invention is a wagon assembly for use in gardening and lawn care comprising a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care.
A handle structure is pivotally connected to a forward end of the wagon body structure such that the handle structure can be moved between a stacking position wherein the handle structure extends rearwardly with respect to the wagon body structure and a range of operating positions wherein the handle structure extends forwardly with respect to the wagon body structure. Wheel structures are rotatably connected to the wagon body structure. The wheel structures are constructed and arranged to enable the wagon assembly to be rolled manually by exerting force on the handle structure in the operating positions.
Upwardly facing supporting surfaces are constructed and arranged to support a first similar wagon assembly aligned above the wagon assembly in a stable stacking and nesting relation, with the handle structure of the wagon assembly in the stacking position and disposed between the wagon body structure of the wagon assembly and a wagon body structure of the first similar wagon assembly, such that portions of wheel structures of the first similar wagon assembly are disposed between upper peripheral edges of the wagon body structure. Downwardly facing stacking surfaces are constructed and arranged to engage upwardly facing supporting surfaces of a second similar wagon assembly such that portions of the wheel structures of the wagon assembly are disposed below upper peripheral edges of the second similar wagon assembly when the wagon assembly is aligned above the second similar wagon assembly in a stable stacking and nesting relation.
Conventional wagons also fail to provide an adequate surface on which gardeners can arrange certain items and materials during gardening and lawn care. Typically, a gardener must take the items he or she wishes to use from the wagon and lay them out on the ground. This provides a greater opportunity for the gardener to lose those items placed on the ground and for dirt and other debris to collect on these items.
Accordingly, it is also an object of the present invention to provide a wagon assembly having a working surface which allows a user to arrange items and materials used in gardening and lawn care on the working surface.
The object of providing a wagon with an adequate surface on which items and materials can be arranged is accomplished by providing a wagon assembly for use in gardening and lawn care comprising a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care. A handle structure has a pair of generally opposed surfaces. The handle structure is connected to a front end of the wagon body structure such that the handle structure can be moved between a work station position, wherein the handle structure extends rearwardly with respect to the wagon body structure, and a range of operating positions, wherein the handle structure extends forwardly with respect to the wagon body structure.
Wheel structures are rotatably connected to the wagon body structure and are constructed and arranged to enable the wagon assembly to be rolled manually by exerting force on the handle structure in the operating positions. The wagon body structure includes upwardly facing handle supporting surfaces constructed and arranged to support the handle structure in the work station position such that the handle structure extends rearwardly with respect to the wagon body structure and one of the pair of generally opposed surfaces faces generally upwardly with respect to the wagon body structure. The upwardly facing surface provides a work station surface which is constructed and arranged to support items used in gardening and lawn care when the handle structure is in the work station position, thereby facilitating gardening and lawn care activities by allowing a user of the wagon assembly to arrange certain items and materials used in gardening and lawn care on the work station surface.
When performing lawn care and gardening activities, oftentimes it is desirable to be seated. Being seated reduces the need for repeated bending down to the ground to perform such activities as digging and weeding, thereby reducing the likelihood of causing back and knee injury as a result of such bending. Conventional wagon assemblies, however, do not provide any structure on which a gardener can comfortably be seated. Thus, when using conventional wagon assemblies, the user must transport his own seat, such a stool or chair, to the desired location or simply sit on the ground. Therefore, there exists a need for a wagon assembly on which a user can be comfortably seated.
It is accordingly an object of the present invention to meet the above-described need. The present invention is a wagon assembly for use in gardening and lawn care comprising a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care. A handle structure has a pair of generally opposed surfaces. The handle structure is connected to a front end of the wagon body structure such that the handle structure can be moved between a seating position wherein the handle structure extends rearwardly with respect to the wagon body structure and a range of operating positions wherein the handle structure extends forwardly with respect to the wagon body structure. Wheel structures are rotatably connected to the wagon body structure and constructed and arranged to enable the wagon assembly to be rolled manually by exerting force on the handle structure in the operating positions.
The wagon body structure includes upwardly facing handle supporting surfaces constructed and arranged to support the handle structure in the seating position such that the handle structure extends rearwardly with respect to the wagon body structure and one of the pair of generally opposed surfaces faces generally upwardly with respect to the wagon body structure to provide a seating surface constructed and arranged to stably support a person seated thereon when the handle structure is in the seating position, thereby allowing a person to perform gardening and lawn care activities while being seated on the wagon assembly.
There is also a lack of conventional wagons which provide extra storage in addition to the storage provided by the wagon body itself. In the conventional wagon, all the items and materials must be carried in one main compartment. In certain situations, it is not desirable to carry certain items and materials together in the same compartment. A wagon having such additional storage compartments allows certain items and materials using gardening and lawn care to be carried separately from the items and materials carried in the main compartment and allows access to those items and material carried therein.
Accordingly, it is an object of the present invention to provide a wagon assembly having storage compartments in addition to a main compartment. This object is accomplished by providing a wagon assembly for use in gardening and lawn care comprising a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care. Wheel structures are rotatably connected to the wagon body structure. The wheel structures are constructed and arranged to rollingly support the wagon assembly.
A handle structure is constructed and arranged such that the wagon assembly can be rolled manually by exerting force on the handle structure. The wagon body structure is constructed and arranged to provide one or more storage compartments. The one or more storage compartments are constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care, thereby allowing certain items and materials to be carried separately from the items and materials carried in the main compartment and allowing access to those certain items and materials.
Typically, in the conventional wagon the handle is allowed to fall to the ground when the user releases it. In order to grasp the handle and pull the wagon, the user must bend down to the ground and grab the handle. When using a wagon over a long period of time, it may be necessary to repeatedly bend down to the ground and grab the handle to move the wagon. This repeated bending tends to cause back pain in certain individuals. Also, some individuals may have certain physical problems, such as a knee injury, for example, which makes such repeated bending uncomfortable.
Therefore, it is an object of the present invention to provide a wagon assembly which obviates the need for the user to reach to the ground in order to grasp the handle of the wagon. This object is achieved by providing a wagon assembly for use in gardening and lawn care comprising a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care. Wheel structures are rotatably connected to the wagon body structure. The wheel structures are constructed and arranged rollingly support the wagon assembly. The handle structure is constructed and arranged such that the wagon assembly can be rolled manually by exerting force on the handle structure.
A stopping element is constructed and arranged to yieldingly support the handle structure such that (1) the stopping element maintains the handle structure at a stopped position extending forwardly with respect to the wagon body structure and spaced in relation to a ground surface on which the wagon assembly is disposed, thereby facilitating grasping of the handle structure by allowing a user of the assembly to grasp the handle structure without reaching down to the ground surface, and (2) the handle structure can be pivoted downwardly past the stopped position by exerting force in a downward direction on the handle structure sufficient to cause the stopping element to yield and allow the handle structure to move downward.
In the conventional wagon, items and materials carried in the wagon body are removed by reaching into the wagon body and lifting the items and materials therefrom. This arrangement requires a user of the conventional wagon to bend over and lift those items and materials. The causes the user to expend unnecessary effort and, in cases where the items and materials carried in the main compartment are heavy, expose himself to injury.
It is therefore an object of the present invention to provide a wagon assembly which obviates these problems by providing an easier way to remove items and materials stored in a main compartment of a wagon body. This object is accomplished by providing a wagon assembly for use in gardening and lawn care comprising a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care. Wheel structures are rotatably connected to the wagon body structure. The wheel structures are constructed and arranged to rollingly support the wagon assembly.
A handle structure is constructed and arranged such that the wagon assembly can be rolled manually by exerting force on the handle structure. The wagon body structure includes an opening constructed and arranged to permit items and materials used in gardening and lawn care carried in the main compartment to be removed therefrom through the opening. The wagon body structure includes a panel member constructed and arranged such that the panel member can be retained in the opening in an engaged relation, thereby preventing the items and materials carried in the main compartment from passing through the opening, and the panel member can be moved from the opening to permit items used in gardening and lawn care carried in the main compartment to be removed through the opening.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a right front perspective view of a wagon assembly embodying the principles of the present invention showing the assembly prepared for transport with the handle structure in an operating position.
FIG. 2 is a left rear perspective view of the wagon assembly showing the handle structure in a seating or stacking position.
FIG. 3 is a right side elevational view of the wagon assembly showing the wagon assembly in an upright position with the handle structure in a working position.
FIG. 4 is a perspective view of the wagon assembly configured for compact storage with a rear surface of the wagon assembly in contact with the ground.
FIG. 5 is a left rear perspective view of the wagon assembly embodying the principles of the present invention, showing the assembly with the handle structure in the operating position.
FIG. 6 is a right rear perspective view of the wagon assembly showing an exploded view of a panel member and a lid of a storage compartment in an opened position.
FIG. 7 is a fragmentary perspective view of a front portion of the wagon assembly illustrating a stopping element in the form of a secondary handle structure.
FIG. 8 is a top plan view of the wagon assembly with the handle structure in the operating position.
FIG. 9 is a bottom plan view of the wagon assembly with the handle structure in the operating position.
FIG. 10 is a cross-sectional view of the wagon assembly taken along line X--X of FIG. 8.
FIG. 11 depicts several wagon assemblies with the handle structures of each in the stacking position stacked upon one another in a nesting relation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring more particularly to the drawings, a wagon assembly embodying the principles of the present invention, generally designated 10, is shown in FIGS. 1-11 and generally includes a wagon body structure, generally designated 12, and a handle structure, generally indicated by reference numeral 14. The body structure 12 of the wagon assembly 10 is constructed and arranged to be stacked on top of an identical or similar wagon assembly body structure. The body structure 12 of the wagon assembly 10 is also constructed and arranged to receive a second wagon assembly stacked on top thereof so that a plurality of similar wagon assemblies 10 can be easily stacked. Referring to FIG. 1, it is seen that the major components of the wagon assembly 10 are the wagon body structure 12, the handle member or structure 14, a removable panel member 16, a pair of rotatable front wheel structures 18, in the form of caster wheel assemblies, and a pair of rotatable rear wheel structures 22.
Referring to FIG. 2, the handle member 14 has a pair of generally opposed surfaces 15a, 15b and is pivotally connected to the wagon body structure 12 for pivotal movement about a transverse horizontal axis at the forward end of the wagon body structure 12. The handle member 14 can be pivoted from a fold down seat position (also referred to as a stacking or work station position), shown in FIG. 2, through a range of operating positions, to an upright working position, shown in FIG. 3. When the handle member 14 is in the fold-down seat position, shown in FIG. 2, the handle member 14 extends rearwardly with respect to the wagon body structure 12 and is essentially horizontal. In this fold-down seat position, the handle member 14 is supported on a pair of upwardly facing handle supporting surfaces in the form of parallel ledges 30 formed along a partitioned upper portion 32 of the body structure 12.
When in the upright work position, the wagon assembly 10 is positioned in an upright position and is supported on its rear end surface 34. In this position, the handle member 14 is pivoted from the fold-down seat position until it is essentially parallel to the ground, and is supported by a front end surface 36 of the wagon body structure 12. As can be seen clearly from FIG. 3, the handle structure 14 provides an upwardly facing working surface, in the form of surface 15a, which allows a user of the wagon assembly to arrange certain items and materials used in gardening and lawn care thereon.
Each of the front wheel structures 18 is held rotatably on separate independent axles 40, 42. The individual axles 40, 42 operate independently and permit omni-directional or three hundred and sixty degree rotation of each front wheel structure 18 on the plane of contact with the ground surface 38. An upper end of each front axle 40 or 42 is rotatably secured to the partitioned portion 32 of the wagon body structure 12 with a locking cap 50. A washer element 44 mounted on each front axle 40, 42 maintains the proper vertical position and attitude of each axle 40, 42 with respect to the wagon body structure 12. This configuration for attaching the front wheel structures 18 is commonly known as a caster wheel assembly.
FIG. 2 shows that the partitioned upper portion 32 includes a plurality of essentially rectangular storage compartments of various sizes and depths, a plurality of essentially rectangular trays of various sizes, and a plurality of well structures with open tops. Some wells and compartments are provided with perforations 33 which are best seen in FIGS. 8 and 9 which function as drainage holes therefor. These structures are molded into the partitioned upper portion 32 of the wagon body structure 12. The partitioned upper portion 32 also includes a main compartment or deep central compartment 52 that extends from the removable panel member 16 at a rear end 53 of the wagon body structure 12 to a shallow front tray 54 that extends transversely across a portion of the front end of the wagon body structure 12.
A compartment 56 with a hinged lid or cover element 58 is integrally formed in a central portion of the left side of the partitioned upper portion 32, and a deep partitioned open compartment 60 is formed in a central portion of the right side. An open well 62 is formed at each front corner of the partitioned upper portion 32 of the wagon body structure 12 on either side of the shallow front tray 54. An open well 64 is also located at both rear corners of the partitioned upper portion 32 of the wagon body structure 12 on either side of the deep central compartment 52 that runs longitudinally along the center of the wagon body structure 12.
The pivotable cover element 58 of the storage compartment 56 is held in a closed position by a snap catch 66 at a center front portion thereof. The cover element 58 opens and closes by pivoting about a pair of elongated cylindrical hinge elements 68 each of which is supported on each end thereof by a planar end member 75 integrally molded in a portion of the wagon body structure 12. A pair of opposing arcuate structures 70 integrally molded on an outer surface of a rear portion of each side of the cover element 58 snap onto each hinge element 68 to pivotally secure the cover element 58 thereto. The cover element 58 is easily disengaged from the hinge elements 68 by rotating the cover element 58 rearward about the hinge elements 68 slightly past the point at which the cover element 58 is perpendicular to the horizontal plane of the wagon body structure 12. The outward force on the pair of hinge elements 68 in the cover element 58 causes the hinge elements 68 to snap away from the opposing arcuate structures 70, thereby completely disengaging the cover element 58 from the compartment 56.
The partitioned open compartment 60 in the central portion of the right side of the partitioned upper portion 32 is a deep, rectangular compartment subdivided into four small, longitudinally aligned, open wells 71 by molded-plastic, vertical partition elements 72 rising from the bottom of the partitioned open compartment 60 to a height of less than one-half the depth of the partitioned open compartment 60. The configuration of the partitioned open compartment 60 can accommodate a variety of items of different sizes and shapes, particularly those used in gardening and lawn care.
Two pairs of stake pocket elements 73 at the front and rear, respectively, of the partitioned upper portion 32 provide structure for an optional stake bed in the partitioned upper portion 32 to allow for a larger functional area in the wagon body structure 12.
A pair of tool clip elements 74 are attached to the left side of the wagon body structure 12 to detachably hold tools with larger diameter handles such as rakes, hoes, edgers, etc. for transport or storage. The tool clip elements 74 are constructed in accordance with the teachings of commonly owned U.S. Pat. No. 5,615,903, the disclosure of which is hereby incorporated by reference into the present specification. The tool clip elements 74 accomplish the attaching function by utilizing a snap-in action. Raised emblems 76 are molded into an upwardly facing portion of the left side of the wagon body structure 12 to indicate the position of the clips.
A second pair of tool clip elements 78, similar to the pair of tool clip elements 74, are attached to the right side of the wagon body structure 12 to detachably hold tools with smaller handles for transport or storage. The pair of tool clip elements 78 also accomplish the attaching function by utilizing a snap-in action. Raised emblems 80 are molded into an upwardly facing portion of the right side of the wagon body structure 12 to indicate the position of the clips.
The handle member 14 is a single molded piece with a transverse element 82 at the top that includes a cylindrical grip portion 84 and a pair of extension elements 86 at the bottom. FIGS. 1, 2 and 3 show that the handle member 14 assumes various positions with respect to the wagon body structure 12 including the fold-down seat position, shown in FIG. 2, and the working position, shown in FIG. 3. As shown in FIG. 9, the handle member 14 is connected to the wagon body structure 12 by a pivot rod 88 which is secured to the body structure 12 with a pair of attaching elements 90 and suitable attaching hardware structures 92. The cylindrical grip 84 has a grooved gripping surface 94 that includes a plurality of equally spaced longitudinally extending grooves running parallel to the transverse element 82 and a plurality of equally spaced arcuate grooves extending circumferentially around the transverse element 82. There are two open areas formed in the handle member 14. An open area 96 is formed at the top of the handle member 14 and an open area 98 is formed at the bottom. The open area 96 at the top of the handle member. 14 allows complete circumferential contact when manually grasping the cylindrical grip 84.
The recessed portion or open area 98 at the bottom of the handle member 14 enables the handle member 14 to rotate past a secondary handle structure or fixed molded body handle element 100 integrally formed on a front end portion 102 of the wagon body structure 12. As best shown in FIG. 7, a plurality of raised surface areas 106 integrally formed along a bottom surface 104 of the handle member 14 extend into the open area 98. The molded body handle element 100 includes a pulling grip 108 that attaches to the body handle element 100 with any suitable type of attaching hardware 110 (see FIG. 9). The pivot rod 88, the two attaching members 90, and the suitable attaching hardware 92 cooperate to rotatably secure the handle member 14 to the wagon body structure 12.
An upper portion of the pulling grip 108 surface is also shaped to include a pair of raised surface areas 112. The pair of raised surface areas 112 on the pulling grip 108 are positioned to make contact with the pair of raised surface areas 106 on the handle member 14 as the handle member 14 pivots about the pivot rod 88. The pair of raised surface areas 106 on the handle member 14 make contact with the pair of raised surface areas 112 on the pulling grip 108 and resists the further rotation of the handle member 14 at one point in the rotation thereof about the pivot rod 88. Thus, the body handle element or secondary handle structure 100 acts as a stopping element which yieldingly supports the handle structure at a stopped position extending forwardly with respect to the wagon body structure 12 and spaced above the ground.
As shown in FIG. 6, the removable panel member 16 at a rear end 114 of the wagon body structure 12 is guided into proper placement in a channeled rear opening 116 in the wagon body structure 12 by a pair of guide tracks 118 molded into the rear end 114 of the wagon body structure 12. The guide tracks 118 on each side of the channeled rear opening 116 each receive an extended guiding element 120 integrally formed on opposite sides of the removable panel member 16 to hold the panel member 16 in place to form a rear wall of the main compartment 52. Two cylindrical position pin elements 122 on the bottom of the panel member 16 seat the panel member 16 in the proper position by engaging with a pair of positioning holes 124 at the bottom of the rear end 114 of the wagon body structure 12. It can be clearly seen from the drawings that removal of the panel member 16 allows one to easily remove items and materials used in gardening and lawn care through the opening 116.
The pair of rotating front wheel structures 18 are made of molded plastic and define a bore which extends partially through the center of each allowing them to be rotatably mounted upon individual axles 40, 42. The pair of rotating front wheel structures 18 are essentially annular molded plastic members, smaller than the pair of rotating rear wheel structures 22, and are preferably molded in a color contrasting to the molded natural colors of the wagon body structure 12 and the handle member 14.
The pair of rotating rear wheel structures 22 are made of molded plastic and each defines a central bore allowing them to be rotatably mounted upon a shaft 126, beneath the underside surface 48 of the wagon body structure 12. The rotating rear wheel structures 22 are retained on the shaft 126 by a pair of suitable rear end caps 128 (see FIG. 5) that attach to the ends of the shaft 126. The pair of rotating rear wheel structures 22 are also essentially annular molded plastic members and are preferably molded in a color contrasting to the molded natural colors of the wagon body structure 12 and the handle member 14. FIG. 9 shows that the shaft 126 is rotatably held on the underside surface 48 of the body structure 12 by a pair of outer retaining elements 130 and a pair of inner retaining elements 132. Proper positioning of rear wheel structures 22 with respect to the body structure 12 is maintained by a pair of spacer elements 134 each of which is positioned adjacent a protruding inner hub structure 135 on each rear wheel structure 22. The cross-sectional view of FIG. 10 shows details of the stake pocket elements 73 and the structural reinforcing elements 138. These structural reinforcing elements provide strength and stability between the main central compartment 52 and the deep partitioned open compartments 60.
Although the handle member 14 can be rotated approximately 270 degrees from the fold-down seat position, shown in FIG. 2, to the working position, shown in FIG. 3, the handle member 14 functions mainly in three specific operating positions depending upon whether the wagon assembly 10 is being used as a seat, as a wagon or as a work station. When the wagon assembly 10 is being used as a seat or when it is being stored or stacked, the handle member 14 is folded down into the wagon body structure 12 as shown in FIG. 2. When functioning as a seat, the four wheel structures 18 and 22 rollingly engage the ground surface 38 and the user can sit on the central portion of the handle member 14 and use his or her legs to roll the wagon assembly 10 along the ground 38. When the handle 14 is in the fold-down position, the user has access to the compartments and wells in the partitioned upper portion 32. It can also be seen that in this fold-down position, the handle member 14 can also be used as a work station surface which allows a user to arrange items and materials used in gardening and lawn care thereon.
The wagon assembly 10 can also be stacked in a nesting relation with other wagon assemblies when the handle is in the fold-down (or stacking) position, as shown in FIG. 11, or stored in an upright nonrolling position, as shown in FIG. 4. Referring to FIG. 11, multiple wagon assemblies 10 can be stacked in a nested relation on a pallet 140 for shipment from the manufacturer to the seller. This stacked and nested relationship enables the wagon assembly 10 to be sold fully assembled, while enabling storage and inventory aspects for both the manufacture and seller to be manageable and cost effective. The stack can be banded or tied together to facilitate storage and transportation of the wagon assemblies 10 at the manufacturing location as well as the location of sales. To stack the wagon assemblies, the handle member 14 is pivoted down to the fold-down or stacking position to rest on the pair of parallel ledges 30 on the wagon body structure 12. Then, a first wagon assembly 10 is placed on top of a second wagon assembly 10 so that the front wheel structures 18 of the first assembly partially enter the open wells 62 of the second assembly 10, the rear wheel structures 22 of the first assembly partially enter the open wells 64 of the second assembly, and the downwardly facing stacking or underside surface 48 of the first assembly rests upon the upper surface 15b of the handle member 14 of the second assembly. The upper surface of the handle structure 14 and upper surfaces of the upper peripheral edges of the wagon body structure 12 and the open wells 62, 64 provide upwardly facing supporting surfaces which support a similar wagon assembly stacked thereon. Also, the bottom surfaces of the wagon body structure 12 and the lowermost portions of the wheel structures 18, 22 define downwardly facing stacking surfaces.
The second operating position of the handle member 14 is shown in FIGS. 5, 6, 7, 8 and 9 and is called the forward extended position, the transport position, or the operating position. When the handle member 14 is disposed in this position, the four wheel structures 18 and 22 are in rolling engagement with the ground or support surface 38 and the grip 84 on the transverse element 82 is elevated higher above the ground 38. In this position, the handle member 14 extends angularly upward from the wagon body structure 12 and forms an acute angle with the ground 38. The handle member 14 is maintained in this angled forward extended position by the contact between the raised surface areas 106 on the handle member 14 and the raised surfaces 112 on the grip 108. The weight of the handle member 14 is insufficient to overcome the contact resistance offered by the raised surfaces 106 and 112 so that the grip 84 is conveniently elevated above the ground for the user to grasp without bending over. In this position, the wagon assembly 10 can be used as a wagon to carry tools, equipment, plants or many other items. The user can push/pull the wagon assembly 10 in any direction because of the omni-directional front wheels 18. The user can also freely lift the handle structure 14 to elevate the grip structure 84 to accommodate tall users because this upward movement rotates the handle structure 14 away from the direction of contact of the surfaces 106 and 112. The wagon assembly can be easily moved or towed using the molded body handle element 100 as well. If sufficient downward force is applied to the handle member 14, the raised surface areas 106 on the handle member 14 and the raised surface areas 112 on the grip 108 can move past one another because both the raised surface areas 106 on the handle member 14 and the raised surface areas 112 on the grip 108 are preferably formed of a resilient deformable elastic material that returns to their original shapes after being depressed. By lowering the handle member 14, it can accommodate children or shorter adults.
The removable panel member 16 can be disposed in an engaged relation with opening 116 formed in the rear end 114 of the wagon body structure 12, or removed therefrom. The removable panel member 16 can be fixed in place during loading and transport operations, and removed to facilitate unloading operations. The main compartment 52 can be easily emptied by manually grasping the secondary handle structure 100 and lifting the wagon assembly 10 so as to dump the contents of the main compartment outwardly through the opening 116.
The rotatable properties of the two independent rotating front wheel structures 18 allow the wagon assembly 10 to be easily and rapidly maneuvered into a position or space that will accommodate the exterior dimensions of the wagon assembly 10 by steering the rotational and linear movement of the assembly in either a forward or rearward direction. The two rotating front wheel structures 18, on freely rotating vertical axles 40, 42, provide a degree of rotational flexibility with respect to the ability to change the direction of forward movement, while the wheels 18, 22 cooperate to form a stable four point base. This four point base 18 and 22, together with a low center of gravity of the wagon assembly 10 and an attractive rectangular, length to width ratio of the wagon body structure 12, provides an added stability during the movement and use of the wagon assembly 10 that helps to prevent tipping of the wagon assembly 10.
The third operating position of the handle is shown in FIG. 3 and is referred to as the working position of the wagon assembly 10. In this configuration the wagon assembly is set upright so the rear end surface 34 is resting on the ground surface 38 and the wheels 18 and 22 are not in contact with the ground 38. The third operation position of the handle 14 is then essentially parallel to the ground because the handle member 14 is rotated about the pivot rod 88 until the handle member 14 contacts and is supported by the front end surface 36 of the wagon body structure. In this configuration, the handle structure 14 provides a convenient working surface on which a user may arrange various items and materials associated with gardening and lawn care.
It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of illustrating the functional and structural principles of this invention and is subject to change without departure from such principles. Therefore, the present invention includes all modifications encompassed within the spirit and scope of the following claims.
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A wagon assembly for use in gardening and lawn care comprises a wagon body structure constructed and arranged to provide a main compartment. The main compartment is constructed and arranged to accommodate the carriage of items and materials used in gardening and lawn care. A handle structure has a pair of generally opposed surfaces. The handle structure is connected to a front end of the wagon body structure such that the handle structure can be moved between a seating position wherein the handle structure extends rearwardly with respect to the wagon body structure and a range of operating positions wherein the handle structure extends forwardly with respect to the wagon body structure. Wheel structures are rotatably connected to the wagon body structure and constructed and arranged to enable the wagon assembly to be rolled manually by exerting force on the handle structure in the operating positions. The wagon body structure includes upwardly facing handle supporting surfaces constructed and arranged to support the handle structure in the seating position such that the handle structure extends rearwardly with respect to the wagon body structure and one of the pair of generally opposed surfaces faces generally upwardly with respect to the wagon body structure to provide a seating surface constructed and arranged to stably support a person seated thereon when the handle structure is in the seating position, thereby allowing a person to perform gardening and lawn care activities while being seated on the wagon assembly.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional application No. 62/186,393 filed on Jun. 30, 2015, the disclosure of which is incorporated by reference.
FIELD
[0002] This invention relates to the field of health and more particularly to a system, method, and apparatus for reducing health risks from electronic devices such as cellular phones.
BACKGROUND
[0003] In recent years, cellular phone usage has spiraled to a point where almost everyone in the country has and uses a cellular phone. Various transmission protocols and transmission frequencies have been used, often varying by geographic region. Examples of protocols include CDMA, TDMA, GSM, etc., while examples of transmission frequencies include 900 MHz, 2.4 GHz, etc.
[0004] With every new technology, new risks and issues emerge. For example, it is well known that using a cellular phone while driving (or performing other tasks) distracts the driver/operator, often leading to accidents. Accidents from using a cellular phone are easily measured and those who use cellular phones while operating equipment such as vehicles and trucks are usually aware of the risks, yet often ignore such risks.
[0005] Ever since the early deployment of cellular technology, a lesser quantifiable risk was recognized due to the proximity of a considerable power output of radio frequency emissions in close proximity to the user's head, and hence, the user's brain. Many studies have been performed and data analyzed showing at least some increase of risk from the use of cellular technology. Early worries related to the use of transmission frequencies in the microwave range, which are known to resonate with water molecules, thereby increasing temperatures of the water molecules, as is known and used in microwave ovens.
[0006] Some of these studies were refuted, especially by those with vested interests such as cell phone operators and manufacturers, but still, there are many indications that there is at least some health risks in using a cellular phone in close proximity to one's head.
[0007] What is needed is a device/system that will react to harmful emissions from electronic devices such as cellular phones, increasing emissions of wavelengths that have been shown to be beneficial to an individual's health. For example, The International Agency for Research on Cancer (IARC), an organization within the World Health Organization, has classified radio frequency fields (e.g., those emitted by cellular phones) as “possibly carcinogenic to humans.” This declaration is based upon limited evidence from human studies, limited evidence from studies of radio frequency energy and cancer in rodents, and weak mechanistic evidence (from studies of geno-toxicity, effects on immune system function, gene and protein expression, cell signaling, oxidative stress, and apoptosis, along with studies of the possible effects of radiofrequency energy on the blood-brain barrier). In another example, the National Cancer Institute (NCI) has stated that: “Studies thus far have not shown a consistent link between cell phone use and cancers of the brain, nerves, or other tissues of the head or neck. More research is needed because cell phone technology and how people use cell phones have been changing rapidly.”
SUMMARY
[0008] A process for producing biotech adapters includes ionization of inks that are later used to print on any of a multitude of surfaces while under the influence of specialized electromagnetic radiation, thereby such printing creates the missing frequency that will complete the man-made frequency thus obtaining a bio compatible frequency known to be beneficial to the health of the user. For example, the process is used to print a biotech adapter having an adhesive backing. The biotech adapter is then attached (e.g. by the adhesive) to the user's electronic device (e.g., cellular phone), preferably at a location where such harmful radio waves are emitted in the direction of the user's head. One preferred location is directly on the battery, when possible. The biotech adapter reacts to the harmful radio waves, completing the missing radio waves by emitting radio waves that are known to be beneficial to humans.
[0009] In one embodiment, a biotech adapter is disclosed including a substrate with an adhesive backing. There are a plurality of inks that, prior to printing, are subjected to an ionization field for a period of time (e.g., 15,000 VDC for 48 hours) for increasing the integration of the scalar component by increasing the polarization of the Van der Waals forces of each of the inks. The biotech adapters are then printed by a printing press. A scalar generator is interfaced to the printing press such that when the printing press deposits the inks onto the substrate, two electromagnetic waves are present at the substrate with a nonzero orbital angular momentum, such that the two electromagnetic waves cancel each other out by counter phase at the location at which the ink is deposited, the electromagnetic waves having a field frequency. The biotech adapter has ink so deposited by the printer and possesses an integrated scalar characteristic of a magnetic oscillation wavelength close to that of the structure of water.
[0010] In another embodiment, a system for producing biotech adapters is disclosed including an ionization device for ionizing one or more inks prior to printing of the biotech adapter and electromagnetic wave generators. Each electromagnetic wave generator is interfaced to a loop coil for the production of an orbital angular momentum. The system includes a printer that uses the inks after ionization to print the biotech adapter. For each print mechanism of the printer, there are two loop coils positioned at equal distance from the point where the inks are deposited on the biotech adapter. In this, a second loop coil of the two loop coils is phase shifted by 180 degrees from a first loop coil of the loop coils, and accordingly, an orbital angular momentum is produced in order to introduce a torsion component into the inks of the biotech adapter.
[0011] In another embodiment, a biotech adapter is disclosed including a substrate and inks printer on the substrate. The inks include a torsion component such that the inks produce radio waves that are beneficial to lifeforms when exposed to radio waves in the microwave range.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention can be best understood by those having ordinary skill in the art by reference to the following detailed description when considered in conjunction with the accompanying drawings in which:
[0013] FIG. 1 illustrates a view of a container of ink being ionized on a ionization device.
[0014] FIG. 2 illustrates a view of the ionization device.
[0015] FIG. 3 illustrates an exemplary schematic view of the ionization device.
[0016] FIG. 4 illustrates an exemplary schematic view of one field generator used in the fabrication process.
[0017] FIG. 5 illustrates an exemplary coil used in the fabrication process.
[0018] FIG. 6 illustrates a pair of the coils arranged in one direction around a printing mechanism.
[0019] FIG. 7 illustrates a pair of the coils arranged offset by 90 degrees around a printing mechanism.
[0020] FIG. 8 illustrates an exemplary six color printing system of the prior art.
[0021] FIG. 9 illustrates an exemplary printing system outfitted with a pair of coils, one at each end.
[0022] FIG. 10 illustrates an exemplary printing system outfitted pairs of coils, one pair for each print mechanism.
[0023] FIG. 11 illustrates an exemplary printing system outfitted pairs of coils, one pair for each print mechanism and a pair of coils, one at each end.
[0024] FIG. 12 illustrates a schematic view of the operation of two coils.
[0025] FIG. 13 illustrates a second schematic view of the operation of two coils.
[0026] FIG. 14 illustrates a third schematic view of the operation of two coils.
[0027] FIG. 15 illustrates a perspective view of a device onto which the biotech adapters printed as per the process are to be applied.
[0028] FIG. 16 illustrates a rear plan view of the device onto which the biotech adapters printed as per the process have been applied.
DETAILED DESCRIPTION
[0029] Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Throughout the following detailed description, the same reference numerals refer to the same elements in all figures.
[0030] Throughout this description, a cellular phone is used as an example of a device onto which biotech adapters are installed. A cellular phone is used as an example but there are many devices that would benefit the inclusion of such biotech adapters, all of which are anticipated and included here within. Further, although detail descriptions of printing biotech adapters onto a sticky-backed label are shown, there is no limitation as to what substrate the printing targets as it is equally anticipated to use the same or a similar process to print directly upon objects such as electronic enclosures, electronic device cases, electronic device doors, antenna, articles of clothing (e.g., hats), etc.
[0031] Referring to FIGS. 1-3 , views of an exemplary ionization device 10 are shown. Before printing, the ink (shown in a container 12 ) is ionized by exposing the ink to a high voltage direct current potential. The ionization device 10 has a charged plate 24 upon which the container 12 with ink is placed. The plate 24 is insulated by a high voltage insulator 24 to reduce leakage through the enclosure 20 . Although any source of power is anticipated, in the example shown, either 110 VAC or 220 VAC is provided to the ionization device 10 through a power cord 22 .
[0032] An exemplary circuit is shown in FIG. 3 having a line voltage section 25 that drives a four to six (4-6) kilovolt trigger coil (e.g., as those that are often used to trigger Xenon flash tubes) with pulses through a capacitor C 1 . The high voltage output windings of the trigger coil is converted to direct current (DC) through a diode voltage-doubler using two high voltage diodes and two high voltage capacitors. In this example, a neon bulb 23 is used to limit current to the charged plate 24 . It is preferred that the trigger coil, T 1 , have isolated windings to reduce the potential of electrocution.
[0033] Although a range of DC voltage potentials is possible, in one embodiment, the DC voltage potential at the charged plate 24 is 15,000 Volts DC. In a preferred embodiment, the charged plate 24 is made of copper.
[0034] It is desirable that the ink be positioned within ten centimeters (10 cm) of the charged plate 24 and that the ink be exposed to the ionization field for approximately 48 hours.
[0035] Referring to FIG. 4 , an exemplary schematic view of one field generator used in the fabrication process is shown. In this exemplary field generator, a source of a sine wave 52 produces a sine wave frequency of 8.06544 Hz, a frequency that is known to be beneficial to life forms. The sine wave of such frequency feeds a non-inverting driver 54 and an inverting driver 56 . The output of the non-inverting driver 54 is in phase with the sine wave produced by the source of the sine wave 52 , while the output of the inverting driver 56 is 180 degrees out-of-phase with the sine wave produced by the source of the sine wave 52 .
[0036] The in-phase sine wave is conducted to a frequency driver 62 and a current driver 66 . The frequency driver 62 connects to a first end 80 of a first winding 80 / 84 of a toroidal coil A (shown in detail in FIG. 5 ) through a capacitor 64 . The current driver 66 connects to a first end 82 of a second winding 82 / 86 of the toroidal coil 140 A through an inductor 68 . Both second ends 84 / 86 of the windings 80 / 84 / 82 / 86 are connected to a return path. Through selection of capacitor 64 and inductor 68 values, the in-phase sine wave is shifted 90 degrees such that the sine wave driving the second winding 82 / 86 is 90 degrees out of phase with the sine wave driving the first winding 80 / 84 .
[0037] The 180 degrees out-of-phase sine wave is conducted to a second frequency driver 72 and a second current driver 76 . The second frequency driver 72 connects to a first end 80 of a first winding 80 / 84 of a second toroidal coil 140 B (same or similar construction to toroidal coil 140 A) through a capacitor 74 . The second current driver 76 connects to a first end 82 of a second winding 82 / 86 of the toroidal coil B through an inductor 78 . Again, both second ends 84 / 86 of the windings 80 / 84 / 82 / 86 are connected to a return path. Again, through selection of capacitor 74 and inductor 78 values, the in-phase sine wave is shifted 90 degrees such that the sine wave driving the second winding 82 / 86 is 90 degrees out of phase with the sine wave driving the first winding 80 / 84 .
[0038] By positioning, for example, a print mechanism between the coils 140 A/ 140 B as shown in FIGS. 6-11 , wave fields are produced as shown in FIGS. 12-14 , as will be described.
[0039] Referring to FIG. 5 , an exemplary coil 140 A (coil 140 B is the same or similar) used in the fabrication process is shown. In this example of the coils 140 A/ 140 B used to generate the proper field, one wire 80 / 84 is preferably wound around the toroidal core 81 in a first direction and the other wire 82 / 86 is wound around the toroidal core 81 in an opposite direction. Using two coils 140 A/ 140 B, positioned at a distance from each other, one fed by the sine wave frequency of 8.06544 Hz and one fed by the 180 degree out-of-phase sine wave frequency of 8.06544 Hz (as described above), the desired Orbital Angular Moment (OAM) as described in FIGS. 12-14 (see below) is produced. In such, the first coil 140 A receives the sine wave in phase (coil 140 A, winding 80 / 84 ) and 90 degrees shifted (coil 140 A, winding 82 / 86 ) and the second coil 140 B receives the sine wave 180 degrees shifted (coil 140 B, winding 80 / 84 ) and 270 degrees shifted (coil 140 B, winding 82 / 86 ).
[0040] In one embodiment, the number of turns of each wire is 3,330 turns on a toroidal core having an overall diameter of approximately 465 millimeters (465 mm) and a thickness of approximately 27 millimeters (27 mm). With this number of turns of wire for each winding 80 / 84 / 82 / 86 and core dimension/composition, each winding 80 / 84 / 82 / 86 is driven with a voltage of approximately 1.29 volts at a frequency of 8.06544 Hz and a current of approximately 0.16 amps.
[0041] Referring to FIGS. 6 and 7 , coils 140 A/ 140 B arranged in one direction around a printing mechanism 15 ( FIG. 6 ) and coils 140 C/ 140 D arranged in an opposing direction (90 degrees offset) around the printing mechanism 15 ( FIG. 7 ) are shown. In order to create the Orbital Angular Moment (OAM) to affect the ionized ink 12 that is used in the printing process, pairs of coils 140 A/ 140 B are positioned at a distance, d, from the individual printing mechanisms 15 . There is no limit to the number of printing mechanisms 15 ; typically there is one printing mechanism 15 for each color to be printed such as six printing mechanisms 15 for a six-color print.
[0042] FIG. 9 shows an exemplary printing system of the prior art.
[0043] As will be shown in FIGS. 9-11 , each printing mechanism 15 is modified to have one pair of dedicated coils 140 C/ 140 D, preferably positioned in line with the plane of printing while the overall printer 19 has one pair of coils 140 A/ 140 B at each end of the printer 19 , preferably offset from the pairs of dedicated coils 140 C/ 140 D by 90 degrees to produce the Orbital Angular Moment (OAM) field at the location of printing.
[0044] For completeness, a source paper tray 11 and a destination paper tray 13 are shown. For brevity reasons, the detail mechanisms of the printer mechanisms 15 are not described, as such is known in the art.
[0045] Referring to FIG. 8 , an exemplary six color printing system 19 of the prior art is shown. In this example of a printing system 19 , six individual printing mechanisms 17 are connected to produce a six-color print output. As an example, a first print mechanism 17 prints cyan 120 , a second print mechanism 17 prints magenta 122 , a third print mechanism 17 prints yellow 124 , a fourth print mechanism 17 prints black 126 , a fifth print mechanism 17 prints silver 128 , and a sixth print mechanism 17 prints gold 130 .
[0046] Referring to FIGS. 9-11 , an exemplary printing system outfitted with pairs of coils is shown. In FIG. 9 , a pair of coils 140 A/ 140 B is shown, one each at each end of the printing system 19 . As above, one coil 140 A has a first set of windings 80 / 84 that are driven by the sine wave frequency of 8.06544 Hz and a second set of windings that are driven by the sine wave frequency of 8.06544 Hz shifted in phase by 90 degrees; and the other coil 140 B has the a first set of windings 80 / 84 driven by the sine wave frequency of 8.06544 Hz that is 180 degrees shifted and a second set of windings that are driven by the sine wave frequency of 8.06544 Hz shifted in phase by 270 degrees.
[0047] In FIG. 10 , pairs of coils 140 C/ 140 D are positioned, one pair surrounding each print mechanism 17 . These pairs of coils 140 C/ 140 D are positioned at a 90 degree offset to the print mechanism 17 , one for each print mechanism 17 . As above, one coil 140 A from each pair has the a first set of windings 80 / 84 that are driven by the sine wave frequency of 8.06544 Hz and a second set of windings that are driven by the sine wave frequency of 8.06544 Hz shifted in phase by 90 degrees; and the other coil 140 B has the a first set of windings 80 / 84 driven by the sine wave frequency of 8.06544 Hz that is 180 degrees shifted and a second set of windings that are driven by the sine wave frequency of 8.06544 Hz shifted in phase by 270 degrees.
[0048] In FIG. 11 the printing system 19 is shown with both sets of coils 140 A/ 140 B. For each print mechanism 17 , a pair of coils 140 C/ 140 D is set on each side of the print mechanism 17 . At each end of the print system 19 is a set of coils 140 A/ 140 B. Again, the coils are driven as described above providing the Orbital Angular Moment (OAM) at the location of printing.
[0049] Referring to FIGS. 12-14 , schematic views of the operation of two coils 140 A/ 140 B are shown.
[0050] A pair of polar and/or non-polar dipoles (coils) 140 A/ 140 B are connected to an electromagnetic wave of a nonzero (I≠0) orbital angular momentum, preferably the medium structure itself is at a nanometric level, and induces a deformation of the forces of Van der Waals. The material (e.g., ink) impacted this way is influenced by the the electromagnetic torsion wave and retains a residual torsion field (or scalar field). The characteristics of this scalar field are related to the frequency of the original electromagnetic wave, and a deformation of the Van der Waals Forces, the density of the material, and the intensity of the magnetic field passing through the material (e.g., ink) or the surface (e.g., paper), and at the time of the angular momentum of the rotation of the electromagnetic wave. The fabrication process includes a material whose scalar field can interact with electromagnetic waves, and the structure and balance of the water molecule.
[0051] One application of such process is to obtain materials in plane surface (2D) or in volume (3D) that attenuate the induced effect on water molecules by hyper frequencies including electromagnetic waves in the microwave frequency range (mainly 0.8 GHz-30.8 GHz).
[0052] In one embodiment, the process is used in the production of labels, protective shells or other items that are positioned on or in an emitter of electromagnetic waves such as on or in a mobile phone, portable computer, music player, etc. Placement of such labels change the impact of electromagnetic waves on the water molecule and, therefore, modify the impact of the electromagnetic waves on the biological milieu (generation of a principle of biocompatibility). Other applications are anticipated such as the creation of materials or containers for the improvement of water quality; as well as, the creation of materials having an interaction with intracellular water, thus with the development and well-being of plants, animals, and humans.
[0053] In FIG. 12 , an electromagnetic wave is generated by magnetic loop antennae 140 A/ 140 B with a principle of de-phasing a phase. This triggers the generation of an electromagnetic wave with a specific orbital angular momentum (OAM Orbital Angular Momentum). This principle is well defined in the framework of quantum kinetics (with J=L+S where J is the angular momentum of the electromagnetic wave, L the kinetic orbital momentum and the S intrinsic angular momentum or Spin). The electromagnetic waves with orbital angular momentum whose value I is different from 0 (zero) have a spiral characteristic which, when penetrating a surface or a volume, induce an effect of torsion at the level of the structure of matter.
[0054] Two specific electromagnetic waves with opposing phases are generated with OAM, such that the electromagnetic waves cancel each other out within the material level that is to be structured (e.g., the ink). This obtains a non-negligible action is on the extremely minute cohesion fields of matter (Van der Waals forces). Thus, if the rotation of the Poynting vectors are in phase, a ‘ Torsion’ and a polarization of a nanometric scale (10-7<r<10-13) is obtained. The flux of the Poynting vector n 1 and n 2 relating to electromagnetic waves OAM (related to the orbital angular momentum) then induce a residual torsion field whose final characteristics are linked to the forces of Van der Waals of the selected material, to the frequency of the electromagnetic wave, to the intensity of magnetic field emitted by the magnetic loop and to the angular momentum of rotation 2 π/I.
[0055] The influence of the torsion field defines itself in a similar way to that of the Alfven waves with Va, the speed of the Alfven waves being proportional to electromagnetic field,
[0000]
Va
=
B
ρ
.
μσ
[0000] and induces a wavelength of type:
[0000]
λ
=
Va
.
2
π
f
[0056] With the magnetic field induced, μo, the permeability of vacuum and ρ the density of ionized particles, which corresponds to the characteristics of Van der Waals forces, and the frequency of the wave.
[0057] The residual field then integrates a scalar component SC (the component of the Alfven wave here, being linked to pure imaginary) whose characteristics are apt to modify a conventional electromagnetic wave and to influence the cohesion of water, especially if the wavelength of λ is harmonic to the cohesion frequency of water.
[0058] The process begins with the targeted material (in which one wishes to integrate a scalar component SC) being submitted to the ionization field allowing for the readiness of the elements. As described with FIGS. 1-3 , ionization of the material (e.g. ink) is preferably performed at 15,000 volts DC for a time period of approximately 48 hours, though other voltages and time periods are anticipated and the present invention is in no way limited to any particular voltage and/or time period.
[0059] Once the material is ionized, the material is subjected to a scalar generator as in FIG. 13 with two electromagnetic waves with a nonzero orbital angular momentum by way of a de-phasing factor: 2π/I. Two electromagnetic waves are emitted at equal distances, d from the targeted material (e.g., ink), one electromagnetic wave being in phase, the other electromagnetic wave being in counter phase as in FIG. 13 with an orbital angular momentum (Torsion factor) as in FIG. 14 . The electromagnetic waves develop in the plane H 1 and H 2 determining the space. The cancellation of electromagnetic waves (according to the phase and counter phase) is populated in a plane H 3 perpendicular to H 1 and H 2 and generates a Torsion factor with a scalar field SC as in FIG. 14 . When the electromagnetic waves cancel each other out, it is the H 3 plane that is structuring itself with a magnetic oscillation wave corresponding to the characteristics of Alfven waves.
[0060] Referring to FIGS. 15 and 16 , a perspective view of a device 7 with the biotech adapters 5 printed as per the above processes and apparatus. FIG. 16 shows the biotech adapters 5 being applied to the device 7 and FIG. 16 shows a rear plan view of the device 7 onto which the biotech adapters 5 have been applied. The inks used to print the biotech adapter 5 comprise a torsion component such that the inks provide waveforms that are beneficial to lifeforms when the biotech adapter is exposed to radio waves in the microwave range, as emitted from devices 7 such as cellular phones, cordless phones, Bluetooth headphones, portable music players, Wi-Fi routers, other wireless devices, other electronic devices, etc.
[0061] Equivalent elements can be substituted for the ones set forth above such that they perform in substantially the same manner in substantially the same way for achieving substantially the same result.
[0062] It is believed that the system and method as described and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely exemplary and explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.
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A process for producing biotech adapters includes ionization of inks that are later used to print on any of a multitude of surfaces while under the influence of specialized electromagnetic radiation, thereby such printing creates the missing frequency that will complete the man-made frequency thus obtaining a bio compatible frequency known to be beneficial to the health of the user. For example, the process is used to print a biotech adapter having an adhesive backing. The biotech adapter is then attached (e.g. by the adhesive) to the user's electronic device (e.g., cellular phone), preferably at a location where such harmful radio waves are emitted in the direction of the user's head. The biotech adapter reacts to the harmful radio waves, completing the missing radio waves by emitting radio waves that are known to be beneficial to humans.
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FIELD AND BACKGROUND OF THE INVENTION
The present invention relates in general to sewing machines and in particular to a new and useful sewing arrangement and device for moving a workpiece to accurately move it through positions for sewing seams thereon.
A similar feed device is known for example from U.S. Pat. No. 4,419,946, dated Dec. 13, 1983 and comprises two links, each provided with a drive, which are articulated to two pitmans and forms with them a parallelogram. At a section of one of the pitmans extending beyond the parallelogram, a work holder pivots about a hinge pin. The hinge pin is connected via toothed or gear belts with an additional drive, in order that the work holder can be pivoted about the hinge pin. The toothed belts, which are disposed in the interior of a link with rectangular hollow section and in a pitman of the same design, are passed over gears and over a pinion connected with the additional drive. During sewing, the parallelogram is pivoted about a fixed bearing, at which the two links engage. Thereby the gears supported in one of the links or one of the pitmans are oscillated about the pinion, which is fastened on a shaft of the additional drive disposed in the fixed bearing. With this drive standing still, the gears are rotated relative to the stopped pinion in the course of the pivoting movement of the parallelogram just far enough for the work holder to be displaced parallel to itself, i.e. in a purely translatory movement.
Because toothed belts are used for the guiding of the work holder, faults may occur due to elongation of the belts, which at high sewing speed are under heavy stress. The amount of these elongations depends on the load as well as on the state of the belts. In case of frequently occurring, relatively strong elongations the belts are moreover subject to considerable wear, so that they may have to be changed often.
SUMMARY OF THE INVENTION
The invention provides a feed device for the execution of purely translatory movements, the device being constructed so as to have little wear and to permit precise transmissions of movements.
In accordance with the invention, a pitman drive known per se, engages at a support of a work holder and it is supplemented by at least one parallelly extending auxiliary pitman which serves only to guide the work holder. From the general science of gears and transmissions pitman drives with two parallel pitmans pivotable about fixed bearings for the nonrotational guiding of a connecting rod are indeed known as parallel link drives, but what is new is to provide such a connecting rod as support of a work holder of a feed device, the pitmans of which are connected with a drive. By reason of the principle, the position of the work holder always remains parallel to an imaginary bar between the two fixed bearings about which the pitmans pivot.
The at least one additional auxiliary pitman used for guiding the work holder causes only a slightly greater inertia of the feed device if it is designed and manufactured according to modern criteria of light-weight construction. Thus also high operating speeds are realizable with the feed device according to the invention.
As the parallel link drive is constructed from solid, positively guided drive elements, the feed device is largely vibration-free and subject to little wear, owing to which hign guide precision is achieved over the long term.
Accordingly, it is an object of the invention to provide a device for moving a workpiece to accurately move it through positions for sewing seams thereon which includes a sewing machine having a support with a work holder movable with the workpiece over the support for moving the workpiece into association with the sewing machine sewing needle and including a pitman drive having a pivotal pitman support connectable to the work holder, the pitman drive including a drive member and parallel guide means connected between the drive member and the pitman support.
A further object of the invention is to provide a sewing arrangement including the sewing machine and a workpiece feed device which includes a workpiece holder having a support of the drive connectable to the holder, the drive including parallel guide means which is hinged to the pitman support connected to the workpiece holder.
A further object of the invention is to provide a driving mechanism for positioning a workpiece on a sewing machine which is simple in design, rugged in construction and economical to manufacture.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a front view of the sewing machine used in both embodiment examples;
FIG. 2 is a top plan view of the sewing arrangement of a first embodiment of the invention;
FIG. 3 is a top plan view of the sewing arrangement of the second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in particular, the invention embodied therein comprises a device for moving a workpiece for accurately moving it through positions for sewing seams thereon by a sewing needle 9 of a sewing machine 3 shown in the sewing arrangement 2 shown in FIG. 1 and supplemented by either the pitman drive of FIG. 2 or that of FIG. 3.
In accordance with the invention, the drive include workpiece holder 10 which is movable over a garment support 13 which comprises the workpiece and holds the workpiece with the work holder so that it may be positioned in respect to the needle for sewing. The positioning drive includes a pitman drive generally designated 20 in FIG. 2 or the pitman drive generally designated 54 in FIG. 3. Pitman drives include a pivotable pitman support such as the support 15 shown in FIG. 2 connected to the work holder 10 in a drive member which in the embodiment of FIG. 2 comprises a rotatable drive disc or control disc 28 as well as parallel guide means which in the embodiment of FIG. 2 comprises a parallel link drive device 24 and in the embodiment of FIG. 3 comprises the parallel link drive 56. In the embodiment of FIG. 2, the parallel guide means include the members 17 and 22 connected between the drive member 28 and the pitman support 15.
EMBODIMENT EXAMPLE 1
Fastened on a Table 1 of a sewing arrangement 2 is a sewing machine 3 which comprises a base plate 4, a standard 5, and an arm 6. Arm 6 terminates in a head 7, in which is mounted a needle bar 8 driven in a known manner, which carries a needle 9.
For holding work to be sewn, a work holder 10 is used which comprises a plate 11 which frictionally grips the work and which is provided with a cutout 12 corresponding to the form of the seam. Arranged on Table 1 is a support plate 13, the top side of which is flush with the top of the base plate 4 of the sewing machine 3. Plate 11 rests on this support plate 13.
The work holder 10 is detachably connected with a support 15 by toggle bolts 14. At the support 15 two pitmans 16,17 engage at a common joint.
Pitman 16 is hinged to a link 18, pitman 17 to a link 19, link 18 being arranged parallel to pitman 17 and link 19 parallel to pitman 16. The links 18,19, which together with the Pitmans 16,17 form a parallelogram 20 as pitman drive, are arranged to pivot about a fixed bearing 21.
At the support 15, in addition to the pitmans 16 and 17 there engages guide means or an auxiliary pitman 22 which is parallel to pitman 17 and whose opposite end is articulated to a connecting rod 23. Connecting rod 23 is pivotably held at the articulated junction between pitman 17 and link 19.
Together with the connecting rod 23 and support 15, pitman 17 and auxiliary pitman 22 form a parallel link drive 24. Also, connecting rod 23 is articulated to an auxiliary pitman 25 which, at its opposite end, pivotably engages at a fixed bearing 26. The imaginary bar between the two fixed bearings 21, 26 on Table 1 forms, together with link 19, auxiliary pitman 25 and connecting rod 23, a parallel link drive 27.
The links 18 and 19 are drivable by a rotatable control disc 28 which is connected with a motor (not shown) and in which guide grooves 29, 30 are cut. The links 18, 19 have pins on which guide rollers 31, 32 are seated. These guide rollers 31, 32 protrude into the guide grooves 29, 30, shown in FIG. 2 simply as dash-dot circles. As a whole, the feed device according to FIG. 2 is formed by the control disk 28, the parallelogram pitman drive 20, the two auxiliary pitmans 22 and 25 as well as the connecting rod 23 and the support 15 of the work holder 10.
The feed device operates as follows: The sewing arrangement 2 serves for example to sew pockets on garments. The work holder 10, detached from the support 15, are placed on the respective garment and pocket in such a way that the cutout 12 is where later the seam is to be formed. Then the work holder 10, which frictionally retains the garment and the pocket, is moved over the support plate 13 and again connected with the support 15. Thereafter the work cycle of the sewing arrangement 2 can be started. For this purpose the control disc 28 is set in rotatation, whereupon it moves the work holder 10 out of the inactive position shown in FIG. 2 into the sewing position.
Upon rotation of the control disc 28, the links 18 and 19 are swivelled about the fixed bearing 21, so that they change their position relative to each other, as do also the pitmans 16,17 connected with the links 18,19. Because the pitman 17 and the link 19 are part of the parallel link drive 24,27, they too together with the support 15 of the work holder 10 are moved into a new position. Being guided by the two parallel link drives 24 and 27, the work holder 10 is shifted transversely only. After the work holder 10 has reached the sewing position, the sewing machine 3 is turned on with the control disc 28 continuing to run, and the desired seam is formed.
EMBODIMENT EXAMPLE 2
The feed device of this example is illustrated in FIG. 3 together with the sewing machine 3 known from the first example, arranged on the Table 1, and also with the work holder 10 displaceable on the plate 13. The work holder 10 serves to hold a workpiece and is moved under the stitch-forming needle 9 of the sewing machine 3 to produce a seam. The new feed device according to FIG. 3 comprises a support 35, on which the work holder 10 is to be attached in a manner known from the description of FIGS. 1 and 2.
Two pitmans 34, 35 pivotable separately of each other engage at the support 33 at different bearing points. At its end away from the support 33, pitman 34 is articulated to a slide 36. Slide 36 is displaceably mounted on a rod 37 secured on the Table 1 by bearing brackets 38. To lock the slide 36 against rotation about the axis of the slide rod 37 a safety device 39 in the form of a U-shaped rail 40 running parallel to rod 37 is provided; it is applied on the Table 1 and serves to receive rollers 41 provided at the slide 36, in that said rollers abut above and below one of the two legs of the sectional rail 40.
The slide 36 has its own drive. To this end a step motor 42 is fastened on the Table 1. A shaft 43 protruding from the housing of this step motor 42 serves to receive a toothed pulley 44 firmly connected with shaft 43. A toothed or gear belt 46 is passed over the pulley 44 as well as over a deflecting wheel mounted on the table. Slide 36 is connected with the toothed belt 46 via a toothed pressure plate 47 adapted to the surface of the toothed belt 46.
The second pitman 35, engaging at the support 33, is articulated at its opposite end to a slide 48. Like slide 36, slide 48 is displaceable on rods 49 and connected with a toothed belt 50. The toothed or gear belt 50 is passed over a deflecting wheel 51 as well as over a toothed pulley 52, which is driven by a step motor 53 attached on the Table 1.
Together with the pitmans 34 and 35 as well as the support 33 of the work holder 10, the two slides 36 and 48 form a pitman drive 54.
For more exact guiding of the support 33 and hence of the work holder 10 the aforesaid pitman drive 54 is provided with an additional auxiliary pitman 55 which is articulated to the support 33 and engages by its opposite end at the slide 48. The auxiliary pitman 55 may be dimensioned and designed just like the pitman 35 and is arranged parallel to the latter. In conjunction with the slide 48 and support 33, the pitman 35 and auxiliary pitman 55 form a parallel link drive 56. As the slide 48 for holding the pitman 35 and auxiliary pitman 55 is wider than the slide 36, it is disposed on two slide rods 49, so that no additional rotation lock of the slide 48, as in the case of slide 36, is needed.
The feed device illustrated in FIG. 3 operates as follows:
After the uptake of two fabric pieces to be sewn together, the work holder 10 is connected with the support 33 in the manner already described. Thereafter the work cycle of the sewing arrangement 2 is started. The work holder 10 is moved from the inactive position shown in FIG. 3 into the sewing position, in that the step motors 42,53 execute a corresponding number of drive steps program controlled with time overlap. Control of the step motors 42, 53 can be affected by a known microcomputer (not shown) which computes the required number of drive pulses for each of the two step motors 42,53 from position data contained in a memory. The step motors 42,53 drive the toothed belts 46,50, which in turn move the slides 36, 48 on the slide rods 37,49. The movement of the slides 36, 48 is transmitted to the pitmans 34, 35 or to the auxiliary pitman 55, the work holder 10 being thus moved in the manner established in the program until the point where the seam is to begin is under the needle of the sewing machine 3. Then the sewing machine is turned on and in cooperation with the program controlled step motors 42,53 the desired seam is formed, the angle position of the work holder 10 being always maintained.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
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A sewing arrangement is provided with a feed device which comprises a drive device, a pitman drive, and a work holder received by a support. The feed device, designed so as to be subject to little wear, permits the execution of purely translatory movements with great accuracy, in that the pitman drive has associated with it a parallel guiding means which together with the pitman drive is articulated to the support of the work holder.
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The invention described herein was made in the course of work under a grant from the United States Department of Health, Education and Welfare.
CROSS REFERENCE TO RELATED APPLICATIONS
This is a division of application Ser. No. 941,847, filed Sept. 13, 1978.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to new antitumor glycosides of the anthracycline series, novel intermediates used for making them, processes for the preparation of said glycosides and the use thereof.
2. The Prior Art
Daunorubicin (also known as daunomycin) and doxorubicin (also known as adriamycin), of which the present compounds are derivatives, are known and are known to be useful in treating certain mammalian tumors.
The compound 9,10-anhydro-N-trifluoroacetyldaunorubicin (X), which is the starting material for the compounds of the present invention is a known compound which is described in British Patent Specification No. 53456/76, owned by the unrecorded assignee hereof.
SUMMARY OF THE INVENTION
The present invention provides, in one aspect thereof, a new class of antitumor anthracyclines of the formula: ##STR2## I: R 1 =COCH 3 ; R 2 =OH; R 3 =OCH 3 ; R 4 =H; X=COCF 3 ;
II: R 1 =COCH 3 ; R 2 =OH; R 3 =OCH 3 ; R 4 =H; X=H;
III: R 1 =COCH 2 OH; R 2 =OH; R 3 =OCH 3 ; R 4 =H; X=H;
IV: R 1 =OH; R 2 =COCH 3 ; R 3 =H; R 4 =OCH 3 ; X=COCF 3 ;
V: R 1 =OH; R 2 =COCH 3 ; R 3 =H; R 4 =OCH 3 ; X=H;
VI: R 1 =OH; R 2 =COCH 2 OH; R 3 =H; R 4 =OCH 3 ; X=H.
Among these six compounds, the four (II, III, V and VI) wherein X is H are the most important.
The invention also provides, in another aspect, a novel method for preparing these compounds utilizing several novel intermediates, which are also within the scope of the invention.
In yet another aspect, the invention provides pharmaceutical compositions which include the novel antitumor compounds of the invention.
Finally, the invention also provides a method of using the novel antitumor compounds of the invention in the treatment of certain mammalian tumors.
The preparation of the compounds of formulae I-VI is based on the synthesis of the tetracyclic aglycones of the formula: ##STR3## VII: R 1 =OH; R 2 =COCH 3 ; R 3 =OCH 3 ; R 4 =H; VIII: R 1 =COCH 3 ; R 2 =OH; R 3 =H; R 4 =OCH 3 ;
and on the subsequent condensation of the aglycones VII and VIII with the known halosugar, 1-chloro-N,O-trifluoroacetyldaunosamine (IX): ##STR4## to form the corresponding N,O protected glycosides, which after treatment with methanol to eliminate the O-protecting trifluoroacetyl group, form the corresponding N-protected glycosides I and IV. After hydrolysis of the N-trifluoroacetyl-protecting group on the sugar moiety, 10-methoxydaunorubicin (II) and 9,10-diepi-10-methoxydaunorubicin (V) are obtained. The corresponding doxorubicin analogs (III) and (VI) are prepared from (II) and (V), respectively, via the 14-bromo derivatives, in accordance with the method described in U.S. Pat. No. 3,803,124 which is owned by the unrecorded assignee hereof. The starting materials for the preparation of the new glycosides (I-VI) of the invention therefore, are the anthracyclinones (VII) and (VIII) which were previously unknown. The novel anthracyclinones (VII) and (VIII) are synthesized, starting from 9,10-anhydro-N-trifluoroacetyldaunorubicin (X), which is described in British Patent specification No. 53456/76 (owned by the unrecorded assignee hereof). The synthetic reaction scheme is set forth below: ##STR5## In order to effect epoxidation of the conjugated double bond present at the C-9, C-10 position in (X), it is first necessary to reduce the keto function to the corresponding α,β-unsaturated alcohol (XI). This reduction is effected using sodium cyanoborohydride in a suitable water-miscible-organic solvent, such as dioxane or dimethoxyethane, in the presence of a mineral acid, and yields quantitatively the corresponding 13-dihydro-derivative (XI). Compound (XI) is then subjected to an expoxidation reaction using -chloroperbenzoic acid in an aprotic solvent, such as methylene chloride, chloroform or acetone. The epoxidation reaction proceeds at a temperature between 25° and 80° C. to give 9,10-epoxide-13-dihydro-N-trifluoroacetyldaunorubicin (XII), as an epimeric mixture. The regeneration of the keto function, with the contemporaneous cleavage of the glycosidic linkage, is performed by oxidation with dimethyl sulfoxide and dicyclohexylcarbodiimide, using pyridinium trifluoroacetate as a catalyst. The course of this oxidation reaction is influenced by the amount of catalyst; using the ratio of substrate to salt of 1:1, compound (XIII) is obtained in high yield. The subsequent introduction of the methoxy group, which is performed by opening of the oxirane ring of compound (XIII) with methanol, in the presence of a catalytic amount of p-toluenesulfonic acid, gives, in the approximate ratio of 7:2, a mixture of the aglycones (VII) and (VIII) which are separated by chromatography on silica gel. Compounds (VII) and (VIII) differ stereochemically at the C-9 and C-10 centers. This is demonstrated by the fact that only compound (VII) forms a 7,9-isopropylidenderivative (XIV) by treatment with 2,2-dimethoxypropane, which shows that the hydroxyl groups at C-7 and C-9 are cis. The pmr spectra of (VII) and (VIII) show that the C-10 H has an equatorial orientation in (VII) and an axial orientation in (VIII). Treatment of (VIII) with 2,2-dimethoxypropane gives 7-methoxy-9,10-diepi-10-methoxydaunomycinone (XV).
The coupling reaction between the aglycones (VII) and (VIII) and the N,O protected halosugar (IX) to form the glycosidic linkage, is carried out in a suitable organic solvent, such as chloroform, methylene chloride or tetrahydrofuran in the presence of a silver salt as catalyst. The thereby obtained N,O protected glycosides are first treated with methanol to eliminate the O-protecting trifluoroacetyl group on the sugar moiety, to give the N-protected glycosides (I) and (IV). These compounds, upon mild alkaline treatment, are converted in quantitative yield to 10-methoxydaunorubicin (II) and 9,10-diepi-10-methoxydaunorubicin (V), respectively.
The corresponding doxorubicin analogs (III) and (VI) are respectively obtained from (II) and (V) via the 14-bromo derivatives, according to the procedure described in U.S. Pat. No. 3,803,124. The new compounds (I-VI) display antimitotic activity and are therefore useful therapeutic agents for the treatment of tumor diseases in mammals.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following examples are given to better illustrate the invention without, however, being a limitation thereof.
EXAMPLE 1
9,10-Anhydro-13-dihydro-N-trifluoroacetyldaunorubicin (XI)
6.0 Grams (10 mmoles) of 9,10-anhydro-N-trifluoroacetyl daunorubicin (X) were dissolved in 2000 ml. of methanol. The solution was acidified with 50 ml. of 0.1 N aqueous hydrochloric acid and then reacted with an aqueous solution of NaCNBH 3 (4.0 g. in 200 ml. of H 2 O). The reaction mixture was stirred at room temperature for 48 hours, while keeping the pH below 4 by the addition of 0.1 N aqueous hydrochloric acid. After neutralization with an excess of solid NaHCO 3 , the solution was evaporated to a residue under vacuum and the residue, after being dissolved in chloroform, was washed with water. The chloroform solution was dried over anhydrous Na 2 SO 4 and the solvent finally removed under vacuum to yield crude 9,10-anhydro-13-dihydro-N-trifluoroacetyldaunorubicin (XI). Pure 9,10-anhydro-13-dihydro-N-trifluoroacetyldaunorubicin (XI) was obtained by chromatographic purification on a column of silicic acid using as the eluting agent the system CHCl 3 :(CH 3 ) 2 CO (95:5 v/v). The pure compound melts at 165° C. (dec.). Visible spectrum (CHCl 3 ) maxima at 520, 556 nm.
EXAMPLE 2
9-Deoxy-9,10 -epoxide-13-dihydro-N-trifluoroacetyldaunorubicin (XII)
To a solution of 8 g. (3.28 mmoles) of 9,10-anhydro-13-dihydro-N-trifluoroacetyldaunorubicin (XI) in 400 ml. of chloroform, there were added 1.08 g.; 6 mmoles of m-chloroperbenzoic acid, and the reaction mixture was warmed at 80° C. for 3 hours. The initial cherry color of the solution gradually changed to red. The reaction solution was then cooled and washed with an aqueous saturated solution of NaHCO 3 , and then with water, after which it was finally dried over anhydrous Na 2 SO 4 . The solvent was evaporated to a residue under vacuum. The residue (2.0 g.), which exhibited, in the visible spectrum (CHCl 3 ), maxima at 490, 504 and 540 mμ is in agreement with what would be expected as a result of the disappearance of the double bond at the C-9, C-10 position of (XI), was a mixture of epimeric epoxides and was used without further purification in the following example.
EXAMPLE 3
9-Deoxy-9,10-epoxide-daunomycinone (XIII)
To a stirred solution of 3.85 g. (6 mmoles) of 9-deoxy-9,10-epoxide-13-dihydro-N-trifluoroacetyldaunomycin (XII) under a nitrogen atmosphere, in 100 ml. of anhydrous dimethylsulfoxide, there were added, one after the other, 3.8 g. (18 mmoles) of dicyclohexylcarbodiimide, 0.5 ml. (6 mmoles) of anhydrous pyridine and 0.23 ml. (3 mmoles) of trifluoroacetic acid. The resulting mixture was stirred at room temperature for 15 hours and then diluted with 500 ml. of chloroform. The chloroform solution was thoroughly washed with water, dried and evaporated to a residue. The residue was taken up in ethyl acetate, the insoluble dicyclohexylurea was filtered off and the filtered solution evaporated to a residue to give 9-deoxy-9,10-epoxide-daunomycinone (XIII) in quantitative yield.
IR: 1720 cm.sub.ν -1 C═O; 1580 and 1620 cm.sub.ν -1 C═O quinone
NMR (CDCl 3 ): at 2.27 (1, CH 3 --C═O); 4.10 (s, OCH 3 ) and 4.18δ (1, H-10).
EXAMPLE 4
10-Methoxy-daunomycinone (VII) and 9,10-diepi-10-methoxy-daunomycinone (VIII)
A solution of 4.3 g. of 9-deoxy-9,10-epoxide-daunomycinone (XIII) in 500 ml. of anhydrous methanol was warmed at reflux temperature for 15 hours in the presence of a catalytic amount of p-toluensulfonic acid. The reaction mixture was then cooled and evaporated to a residue which was then dissolved in 300 ml. of chloroform, washed with an aqueous 5% solution of NaHCO 3 , water, dried over anhydrous Na 2 SO 4 and again evaporated to a residue. The thusly obtained crude material was a mixture of compounds (VII) and (VIII) in the approximate ratio of 7:2. The mixture was chromatographed on a column of silicic acid using the mixture ethylacetate-toluene-petroleum ether (3:2:2 v/v) as the eluting agent. Pure 10-methoxydaunomycinone (VII): (1.5 g.) and 9,10-diepi-10-methoxydaunomycinone (VIII): (0.42 g.), 72% overall yield, were obtained. 10-Methoxydaunomycinone (VII): m.p. 220° C. (dec.); [α] D 20 =+206 (c=0.1, CHCl 3 ); MS: m/e 428 (M+): 396 (M--CH 3 OH), 353 (M--CH 3 OH--CH 3 CO); NMR (CDCl 3 ): 3.51 (s, C-10-OCH 3 ); 4.66 (d, C-10H); 5.31 (q, C-7H), 13.6 and 14.07δ (s, OH phenolic).
9,10-Diepi-10-methoxydaunomycinone (VIII): m.p. 156° C. (dec.): MS: m/e (428 (M+); NMR (CDCl 3 ): 3.64 (s, C-10-OCH 3 ); 4.89 (s, C-10H), 5.12 (q, C-7H), 13.80 and 14.21δ (s, OH phenolic).
EXAMPLE 5
7,9-Isopropyliden-10-methoxydaunomycinone (XIV)
To a solution of 0.1 g. of 10-methoxydaunomycinone (VII) in 10 ml. of anhydrous dioxane there were added 5 ml. of 2,2-dimethoxypropane and a catalytic amount of p-toluenesulfonic acid. The reaction mixture was kept at 50° for 48 hours and then diluted with 50 ml. of chloroform. The thusly diluted solution was washed with an aqueous saturated solution of NaHCO 3 , water and then dried over anhydrous Na 2 SO 4 . The crude residue, obtained by evaporation of the organic solvent, was chromatographed on a column of silicic acid using the mixture chloroform-acetone (95:5 v/v) as eluting agent. Pure 7,9-isopropyliden-10-methoxydaunomycinone (XIV) was obtained.
MS: m/e 468 (M+); 410 (M--(CH 3 ) 2 CO); 378 (M--(CH 3 ) 2 CO--CH 3 OH); NMR (CDCl 3 ): 1.2 and 2.47 (s, 2CH 3 ), 5.47δ (m, C-7H).
EXAMPLE 6
7-Methoxy-9,10-diepi-10-methoxydaunomycinone (XV)
Treatment of 9,10-diepi-10-methoxydaunomycinone (VIII) with 2,2-dimethoxypropane, as described in Example 5, afforded 7-methoxy-9,10-diepi-10-methoxydaunomycinone (XV). MS: m/e 442 (M + ).
EXAMPLE 7
10-Methoxydaunorubicin hydrochloride (II)
To a solution of 0.43 g. (1 mmole) of 10-methoxydaunomycinone (VII) in 200 ml. of anhydrous methylene chloride were added 0.43 g. (1.2 mmoles) of 1-chloro-N,O-trifluoroacetyldaunosamine (IX). Then 0.32 g. (1.2 mmoles) of AgSO 3 CF 3 , dissolved in 26 ml. of anhydrous ether was added to the solution at room temperature with vigorous stirring over a period of 10 minutes. Finally, 0.2 ml. (1.4 mmoles) of anhydrous collidine was added to the reaction mixture. After 40 minutes, the mixture was treated with a saturated aqueous solution of NaHCO 3 and the separated organic phase was evaporated under vacuum. The resulting residue was dissolved in 100 ml. of methanol and kept at room temperature for 5 hours. The residue, which resulted from the removal of the solvent, was chromatographed on a column of silicic acid using the mixture chloroform-acetone (4:1 v/v) as the eluting agent. In addition to unreacted 10-methoxydaunomycinone (VII), there was also obtained 0.26 g. of pure 10-methoxy-N-trifluoroacetyldaunorubicin (I); m.p. 190° C. (dec.): TLC on Kieselgel plate F 254 (Merck) using the solvent system CHCl 3 --(CH 3 ) 2 CO (4:1 v/v): Rf 0.3; NMR (CDCl 3 ): 1.30 (d, CH 3 -CH); 3.52 (s, C-10 OCH 3 ); 5.30 (m, C-7H) and 5.53δ (m, C-1'-H a x WH=7 HZ). The compound (I); 0.26 g. was dissolved in 50 ml. of 0.1 N aqueous sodium hydroxide and after 30 minutes at 0° C., the solution was adjusted to pH 8.6 and repeatedly extracted with chloroform. The combined chloroform extracts, after being dried over anhydrous Na 2 SO 4 , were concentrated to a small volume and acidified at pH 4.5 with 0.1 N methanolic hydrogen chloride to allow crystallization of 10-methoxydaunorubicin (II), as the hydrochloride; m.p. 159° C. (dec.); [α] D 20 ° +316° (c 0.05, CH 3 OH); TLC on Merck Kieselgel HF 254 plate using solvent system CHCl 3 --CH 3 OH--H 2 O (13:6:1 v/v): Rf 0.37.
EXAMPLE 8
9,10 -Diepi-10-methoxydaunorubicin (V)
The coupling reaction between 9,10-diepi-10-daunomycinone (VIII) and the halosugar, i.e., 1-chloro-N,O-trifluoroacetyldaunosamine (IX), as described in Example 7, yielded 9,10-diepi-10-methoxy-N-trifluoroacetyldaunorubicin (IV), which, after a mild alkaline treatment with 0.1 N aqueous sodium hydroxide for 30 minutes at 0° C., gave 9,10-diepi-10-methoxydaunorubicin, isolated as the hydrochloride (V), m.p. 140° (dec.); [α] D 20 ° +252 (C 0.05, MeOH).
EXAMPLE 9
10-Methoxydoxorubicin (III)
A solution of 10-methoxydaunorubicin (II) in a mixture of methanol and dioxane was treated with bromine to give the corresponding 14-bromoderivative which was subsequently treated with an aqueous solution of sodium formate at room temperature for 100 hours according to the technique disclosed in U.S. Pat. No. 3,803,124 to obtain 10-methoxydoxorubicin (III), isolated as the hydrochloride m.p. 195° (dec.) TLC on Merck Kieselgel HF 254 plate using solvent system CHCl 3 --CH 3 OH--H--H 2 O AcOH (8:2:0.6:1.4 v/v) Rf 0.45.
EXAMPLE 10
9,10-Diepi-10-methoxydoxorubicin (VI)
As in Example 9, by following the technique disclosed in U.S. Pat. No. 3,803,124, the treatment of 9,10-diepi-10-methoxydaunorubicin (V) with bromine and then with sodium formate, yielded 9,10-diepi-10-methoxydoxorubicin (VI) which was isolated as the hydrochloride.
BIOLOGICAL ACTIVITY
The compounds according to the invention were tested under the auspices of NCI - National Institute of Health, Bethesda, Maryland, against lymphocytic leukemia P 388 according to the procedure described in Cancer Chomotherapy Reports, part 3, vol. 3, page 9 (1972). The data reported in the table below show the antitumor activity of the new anthracycline derivatives.
TABLE______________________________________Antitumor activity of 10(R)-methoxydaunorubicin and10(R)-methoxy-doxorubicin as compared with -daunorubicin and doxorubicin DoseCompound (mg./kg.) T/C %______________________________________Danunorubicin 16 90 8 98 4 119 2 12410(R)-Methoxydaunorubicin 12.5 133 6.25 115 3.13 110Doxorubicin 16 108 8 171 4 133 2 129 1 11910(R)-Methoxydoxorubicin 50 104 25 115 12.5 127 6.25 125 3.13 1089-cpi-10(S)-Methoxydauno- 50 126rubicin 25 132 12.5 110 6.25 102______________________________________
The new compounds were tested in vivo on CDF mice infected with tumor cells. The i.p. injections were made on days 5, 9 and 13 (4 days interval between each injection) starting from fifth day after tumor transplantation in the mice. The median survival time expressed as percent of controls (T/C %) are reported.
Variations and modifications can, of course, be made without departing from the spirit and scope of the invention.
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Compounds having the formula: ##STR1## wherein (a) when R 1 is --COCH 3 or --COCH 2 OH, R 2 is --OH, R 3 is --OCH 3 and R 4 is --H;
(b) when R 2 is --COCH 3 or --COCH 2 OH; R 1 is --OH, R 3 is --H and R 4 is --OCH 3 ;
and which are useful in treating certain mammalian tumors, are prepared from 9,10-anhydro-N-trifluoroacetyl daunorubicin, a known compound.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image-forming device to form a multi-color image.
2. Description of Related Art
A conventional image-forming device, such as Japanese Patent application publication No. 2002-31933, forms a multi-color image as follows. Firstly, a plurality of developing units forms developer images sequentially on a plurality of corresponding image bearing members (or on one image bearing member, in the four-cycle method) on which latent electrostatic images are formed. Then, those developer images are transferred sequentially to a transfer recipient such as a sheet of paper or an intermediate transfer body.
SUMMARY OF THE INVENTION
It has recently been established that reverse transfer occurs when such an image-forming device forms a multi-color image.
Part of the developer that has been transferred to the transfer recipient from one image bearing member are charged to a polarity opposite to the polarity to which the developing unit has charged. When the second or later image bearing members performs transferring, the developer charged to the opposite polarity is reverse-transferred to the second or later image bearing members due to the reverse transfer.
The reverse transfer is more likely to occur as the amount of developer (amount of toner) that has been transferred to the transfer recipient increases. With the tandem method, for example, the amount of developer involved in the reverse transfer generally increases with later image bearing members positioned on the downstream side in the direction in which the paper is conveyed.
A conventional image-forming device with the simultaneous development/cleaning method (also called the cleanerless method) is not provided with a cleaning device for recovering waste developer. Therefore, if the waste developer (reverse transfer toner) that has been reverse-transferred to the image bearing members is recovered into the developing unit, the developer for the original colors will be mixed with the waste developer.
When charge capability of the waste developer (reverse-transferred toner) that has been reverse-transferred to the image bearing members is higher than that of the developer for the original colors, the waste developer rather than the developer for the original colors will tend to be transferred to the transfer recipient in the development, causing color mixing. In addition, muddying can also occur easily due to difference in charge amount, causing poor image quality.
Furthermore, if the cleaning effect is not sufficiently pronounced even when a cleaning device is provided with a recovering waste developer, the color mixing and muddying can occur in a similar manner to those with the simultaneous development/cleaning method.
In view of the foregoing, it is an objective of the present invention to provide an image-forming device that can form images while suppressing the effects of reverse transfer.
In order to attain the above and other objects, the present invention provides an image-forming device including 1st to N th image bearing members, 1st to N th developing units provided in one-to-one correspondence with the 1st to N th image bearing members, and a transfer unit. N is an integer number equal to or greater than two. The 1st to N th image members have 1st to N th surfaces respectively. The 1st to N th electrostatic latent images are formable on the 1st to N th surface respectively. The 1st to N th developing units have 1st to N th monochromatic developers respectively. The 1st monochromatic developer is of monochromatic black and has a toner particle substantially spherical in shape. The 1st to N th developing units develop the 1st to N th electrostatic latent images with the 1st to N th monochromatic developers respectively in order to form 1st to N th developer images respectively. The transfer unit transfers sequentially the 1st to N th developer images to a recipient in a superimposed manner in order of the 1st to N th developer image.
Another aspect of the present invention provides an image-forming device including a plurality of image bearing members, a plurality of developing units and a transfer unit, The plurality of image bearing members includes 1st to 4th image bearing members. The 1st to 4th image members have 1st to 4th surfaces respectively. 1st to 4th electrostatic latent images are formable on the 1st to 4th surface respectively. The plurality of developing units includes 1st to 4th developing units provided in one-to-one correspondence with the 1st to 4th image bearing members. The 1st to 4th developing units have 1st to 4th monochromatic developers respectively. The 1st monochromatic developer is of monochromatic black and has a toner particle substantially spherical in shape. The 1st to 4th developing units develop the 1st to 4th electrostatic latent images with the 1st to 4th monochromatic developers respectively in order to form 1st to 4th developer images respectively. A total amount of the 2nd monochromatic developer on the 2nd surface and the 3rd monochromatic developer on the 3rd surface is less than an amount of the 1st monochromatic developer on the 1st surface. The transfer unit transfers the 1st to 4th developer images to a recipient in a superimposed manner in order of the 1st to 4th developer image in order to form a black image.
Another aspect of the present invention provides an image-forming method including steps (a) to (d). The step (a) forms 1st to N th electrostatic latent images on a surface formed on an image bearing members, N being an integer equal to or greater than two. The step (b) develops the 1st to N th electrostatic latent images with 1st to N th monochromatic developers respectively in order to form 1st to N th developer images respectively, wherein the N−1 th monochromatic developer being of monochromatic yellow. The (c) transfers sequentially the 1st to N th developer images to a recipient in a superimposed manner in order of the 1st to N th developer image. The step (d) removes residual developer that adheres to each image bearing member while developing each electrostatic latent image.
Another aspect of the present invention provides an image-forming device including at least one image bearing member, a plurality of developing units and a transfer unit. A plurality of electrostatic latent images is formable on at least one image bearing member. The plurality of developing units include 1st to N th developing units. the 1st to N th developing units have 1st to N th monochromatic developers respectively. The 1st monochromatic developer is of monochromatic black and has a toner particle substantially spherical in shape. The 1st to N th developing units develop the plurality of electrostatic latent images with the 1st to N th monochromatic developers respectively in order to form 1st to N th developer images respectively. The transfer unit transfers the 1st to N th developer images to a recipient in a superimposed manner in order of the 1st to N th developer image.
Another aspect of the present invention provides an image-forming device including at least one image bearing member, a plurality of developing units and a transfer unit. 1st to 4th electrostatic latent images are formable on at least one image bearing member. The plurality of developing units includes 1st to 4th developing units provided in one-to-one correspondence with the 1st to 4th image bearing members. The 1st to 4th developing units have 1st to 4th monochromatic developers respectively. The 1st monochromatic developer is of monochromatic black. The 1st to 4th developing units develop the 1st to 4th electrostatic latent images with the 1st to 4th monochromatic developers respectively in order to form 1st to 4th developer images respectively. A total amount of the 2nd monochromatic developer and the 3rd monochromatic developer on the image bearing member is less than an amount of the 1st monochromatic developer on the image bearing member. The transfer unit transfers the 1st to 4th developer images to a recipient in a superimposed manner in order of the 1st to 4th developer image in order to form a black image.
Another aspect of the present invention provides an image-forming device including a plurality of image bearing members, a plurality of developing units, a transfer unit and a cleaning member. The plurality of image bearing members include 1st to N th image bearing members. N is an integer number equal to or greater than two. The 1st to N th image members have 1st to N th surfaces respectively. 1st to N th electrostatic latent images are formable on the 1st to N th surface respectively. The plurality of developing units include 1st to N th developing units provided in one-to-one correspondence with the 1st to N th image bearing members. The 1st to N th developing units have 1st to N th monochromatic developers respectively. The N−1 th monochromatic developer is of monochromatic yellow. The 1st to N th developing units develop the 1st to N th electrostatic latent images with the 1st to N th monochromatic developers respectively in order to form 1st to N th developer images respectively. The transfer unit transfers sequentially the 1st to N th developer images to a recipient in a superimposed manner in order of the 1st to N th developer image. The cleaning member removes residual developer that adheres to each image bearing member after each developer image is transferred to the recipient. Each developing unit develops each electrostatic latent image while removing the residual developer with the cleaning member.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the invention will become more apparent from reading the following description of the preferred embodiments taken in connection with the accompanying drawings in which:
FIG. 1 is a section taken through the side of essential components of a color laser printer in a first embodiment;
FIG. 2 shows the configuration in the vicinity of a photosensitive drum in the first embodiment;
FIG. 3 is illustrative of the cause of reverse-charging;
FIG. 4 is illustrative of the sequence in which developer images are formed and the ease of reverse transfer; and.
FIG. 5 is a section taken through the side of essential components of a color laser printer in a modification of the first embodiment;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An image-forming device according to preferred embodiments of the present invention will be described while referring to the accompanying drawings wherein like parts and components are designated by the same reference numerals to avoid duplicating description.
A first embodiment of the present invention will be described with reference to FIGS. 1 to 4 . FIG. 1 is a side sectional view of a color laser printer 1 according to the first embodiment. As shown in FIG. 1 , the color laser printer 1 has a visible image formation portion 4 , a paper conveyor belt 6 , a fixing portion 8 , a paper supply portion 9 , a stacker 12 , a control portion 10 , and a bias supply unit 11 . The color laser printer 1 forms a multi-color image by sequentially overlaying four color toner images on paper P, where the four colors corresponds to image data that is input from the exterior.
The visible image formation portion 4 has four developing units 51 BK, 51 M, 51 Y, and 51 C; four photosensitive drums 3 BK, 3 M, 3 Y, and 3 C being one-to-one correspondence with the developing units 51 BK, 51 M, 51 Y, and 51 C; four chargers 31 , 32 , 33 , and 34 being one-to-one correspondence with the developing units 51 BK, 51 M, 51 Y, and 51 C; and four exposure devices 41 , 42 , 43 , and 44 being one-to-one correspondence with the developing units 51 BK, 51 M, 51 Y, and 51 C. The developing units 51 BK, 51 M, 51 Y, and 51 C accommodates black (BK), magenta (M), yellow (Y), and cyan (C) toner respectively. The capital letters used as suffixes for the developing units in FIG. 1 refer to the color of the toner housed in the corresponding developing units.
There are two methods of forming a black-colored image: one in which only a monochromatic black developer is used and another in which developers of other colors (such as yellow, cyan and magenta, or red, green, and blue) are overlaid on black-colored developer (mixed-color black development). Mixed-color black development produces blacks of a much higher image quality than monochromatic black development. Therefore, the mixed-color black development is used for forming a black-colored image in the present embodiment.
The configuration of each of the structural components will be described in detail as follows. The four photosensitive drums 3 BK, 3 M, 3 Y, and 3 C that are formed of a member of a substantially circular cylindrical form are disposed rotatably, spaced substantially equidistantly along a line in the horizontal direction (the widthwise direction in the plane of the paper in FIG. 1 ). The substantially circular cylindrical material of each of the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C is an aluminum base member on which a positively-charged photosensitive layer is formed, for example. The aluminum base member is grounded to the ground line of the color laser printer 1 .
Each of the four chargers 31 to 34 is a scorotron type of charger. FIG. 2 shows the detailed configuration of the charger 31 that charges the photosensitive drum 3 BK for forming the black toner image. The charger 31 has a charge wire 36 and a shielding case 37 . The charge wire 36 extends to the axis direction of the photosensitive drum 3 BK (the direction into the paper in FIG. 2 ) facing the surface of the photosensitive drum 3 BK. The shielding case 37 houses the charge wire 36 and is open towards the photosensitive drum 3 BK side. The shielding case 37 is provided with a grid 38 over the open portion.
The surface of the photosensitive drum 3 BK is charged to a positive polarity (such as +700 V) when a high voltage is applied to the charge wire 36 . The charge on the surface of the photosensitive drum 3 BK and the voltage of the grid are kept at substantially the same potential by applying a constant voltage to this grid 38 . The chargers 32 , 33 , and 34 that are provided to correspond to the other photosensitive drums 3 M, 3 Y, and 3 C have the same structure as the charger 31 .
The exposure device 41 will be described referring to FIG. 2 . The exposure device 41 exposes the photosensitive drum 3 BK for forming a latent electrostatic image on the surface of the photosensitive drum 3 BK. As shown in FIG. 2 , the exposure device 41 is disposed on the downstream side of the charger 31 with respect to the direction of rotation of the photosensitive drum 3 BK (clockwise in this figure). A light source of the exposure device 41 outputs a laser beam corresponding to one color component of image data (in this case, black) that is input from the exterior. The laser beam is scanned by the mirrored surfaces of a polygon mirror (not shown) that is driven to rotate by a polygon motor (also not shown), to illuminate the surface of the photosensitive drum 3 BK. Note that large portions of the exposure devices 41 to 44 are omitted from FIGS. 1 and 2 ; only the portions that emit the laser beam are shown therein.
When the surface of the photosensitive drum 3 BK is illuminated by the laser beam, the surface potential of the illuminated portions drops (to +150 V, by way of example) to form a latent electrostatic image on the surface of the photosensitive drum 3 BK. The other exposure devices 42 , 43 , and 44 that are disposed facing the corresponding photosensitive drums 3 M, 3 Y, and 3 C have the same configuration as that of the above-described exposure device 41 , and each outputs a laser beam for the corresponding color, based on image data that is input from the exterior.
The first developing unit 51 BK, which develops the latent electrostatic image formed by black toner, will be described referring to FIG. 2 . As shown in FIG. 2 , the developing unit 51 BK has a toner hopper 54 to house the toner, a supply roller 55 to supply the toner, and a developing roller 52 to bear the toner, within a developing unit case 53 .
The toner hopper 54 is an interior space in the developing unit case 53 and accommodates black toner. An agitator 56 is provided at one end portion within the toner hopper 54 . In the present embodiment, the toner housed in the toner hopper 54 is positively charged, non-magnetic, single-component developer that is formed from a suspended polymer or emulsified polymer. The particles of the toner are substantially spherical to have excellent fluidity.
The supply roller 55 has a roller shaft and an electrically conductive sponge material coated around the metal roller shaft. The supply roller 55 is disposed at the bottom part within the toner hopper 54 . The supply roller 55 is supported rotatably in the same direction as the developing roller 52 (in the counterclockwise direction in FIG. 2 ), facing the developing roller 52 .
The developing roller 52 is disposed rotatably at a position at which the developing roller 52 is in mutual contact with the supply roller 55 . The developing roller 52 is configured of a circular cylindrical member that is made of electrically conductive silicone rubber or the like as a base member. The surface of the developing roller 52 is formed with a coating of a rubber material or a resin comprising fluoride.
The developing roller 52 is disposed in contact with the photosensitive drum 3 BK on the downstream side of the exposure device 41 in the direction of rotation of the photosensitive drum 3 BK. The developing unit 51 BK supplies the toner charged to a positive polarity for the developing roller 52 as a uniform thin layer. Inverted developing method is used to form a toner image while providing the latent electrostatic image of a positive polarity that has been formed on the photosensitive drum 3 BK with the positively-charged toner, at the contact portion between the developing roller 52 and the photosensitive drum 3 BK.
The other developing units 51 M, 51 Y, and 51 C each have a configuration that is similar to that of developing unit 51 BK shown in FIG. 2 , except that the colors of the toner accommodated therein are different (these developing units hold magenta, yellow, and cyan toner, respectively).
The paper supply portion 9 is provided in the lowermost portion of the color laser printer 1 and is configured of an accommodation tray 91 to accommodate the paper P and a pick-up roller 92 to transmit the paper. The paper P that is accommodated in the accommodation tray 91 is taken out one sheet at a time by the pick-up roller 92 and is transmitted to the paper conveyor belt 6 via conveyor rollers 99 or the like.
The paper conveyor belt 6 is formed in a loop and suspended between a drive roller 62 and a driven roller 63 . The paper conveyor belt 6 can run integrally with the paper P supported on the upper surface of the paper conveyor belt 6 . The width of the paper conveyor belt 6 is narrower than the width of the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C. Four transfer rollers 66 , 67 , 68 , and 69 are provided at positions where the four transfer rollers 66 , 67 , 68 , and 69 face the corresponding photosensitive drums 3 BK, 3 M, 3 Y, and 3 C via the paper conveyor belt 6 respectively.
When the drive roller 62 rotates, the paper conveyor belt 6 in a loop also rotates as shown in FIG. 1 . The paper P that has been transmitted by the conveyor rollers 99 or the like is conveyed sequentially between each of the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C and the surface of the paper conveyor belt 6 , then on to the fixing portion 8 .
A suitable transfer bias that is controlled at −10 to −15 μA, by way of example, is applied between each of the transfer rollers 66 to 69 and the corresponding photosensitive drums 3 BK, 3 M, 3 Y, and 3 C in order to electrostatically transfer the toner image that is formed on each photosensitive drum in sequence to the paper P that is conveyed by the paper conveyor belt 6 . Specifically, a voltage having a polarity (in the present embodiment, negative polarity) opposite to that (in the present embodiment, positive polarity) of the charge on each of the corresponding photosensitive drums 3 BK, 3 M, 3 Y, and 3 C is applied to each of the four transfer rollers 66 , 67 , 68 , and 69 .
Taking the toner image formed by black toner as an example, if the transfer bias of a high voltage of a negative polarity is applied to the transfer roller 66 , the toner image on the photosensitive drum 3 BK is transferred to the paper P at the position at which the photosensitive drum 3 BK faces the transfer roller 66 , in other words, at a transfer nip portion TP at which the paper P is in contact with the photosensitive drum 3 BK.
In other words, the application of the transfer bias generates an electric field from the photosensitive drum 3 BK to the transfer roller 66 . The toner image of a positive polarity on the photosensitive drum 3 BK transfers to the paper P electrostatically due to the electric field transfers. The transfer of the toner images on the other photosensitive drums 3 M, 3 Y, and 3 C is done in the same way.
Thus, the toner images of the corresponding colors are transferred sequentially in order of black, magenta, yellow, and cyan by the application of the transfer bias to the corresponding transfer rollers 67 , 68 , and 69 . In other word, the desired multi-color image is created by overlaying toner images sequentially in order of black, magenta, yellow, and cyan onto the paper P. Note that the use of constant-current control over the transfer bias is cited merely as an example, and thus another control method could be used, such as constant-voltage control.
A cleaning brush 105 is disposed at the downstream of the drive roller 62 , facing the surface of the paper conveyor belt 6 . The cleaning brush 105 has a brush provided around the periphery of a substantially circular cylindrical member whose axis extends across the width of the paper conveyor belt 6 . The cleaning brush 105 rotates in contact with the paper conveyor belt 6 . A bias voltage is applied between the cleaning brush 105 and an electrode roller 104 that is provided at a position on the other side of the paper conveyor belt 6 and faces to the cleaning brush 105 .
A recovery roller 106 and a collection box 107 are provided in the vicinity of the cleaning brush 105 . The recovery roller 106 removes toner that adheres to the cleaning brush 105 . The collection box 107 accumulates the toner removed from the cleaning brush 105 by the recovery roller 106 .
The fixing portion 8 is configured of a heating roller 81 , a pressure roller 82 and a fixing sheet 83 . The paper P, on which a multi-color image formed of toner images in four colors is born, is conveyed between the heating roller 81 and the pressure roller 82 via the fixing sheet 83 . The heating roller 81 heats and the pressure roller 82 press the paper P to fix the multi-color image to the paper P.
The stacker 12 is provided on the upper surface of the color laser printer 1 and on the paper discharge side of the fixing portion 8 . The stacker 12 holds the paper P that is discharged from the fixing portion 8 .
The control portion 10 is provided with a well-known CPU to control all the operations of the color laser printer 1 . The control portion 10 also controls the bias supply unit 11 to apply the transfer bias to each of the transfer rollers 66 , 67 , 68 , and 69 ; the cleaning bias between the electrode roller 104 and the cleaning brush 105 , and the voltage to each of the chargers 31 to 34 .
The color laser printer 1 of the present embodiment uses a method simultaneous development/cleaning method by which residual toner that has not been transferred, and thus remains on the photosensitive drum surfaces after the transfer of the toner images from the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C onto the paper P, is recovered into the toner hopper 54 via the developing roller 52 and the supply roller 55 while developing being performed.
Although the precise mechanism that results in the reverse transfer is still not clear, the cause of the reverse transfer, more specifically, the cause of reverse-charging of toner, is deduced from the results of inspection. When a strong electrical field is generated between the toner and the paper, the discharge occurs within the toner layer that has been transferred onto the paper P. When the discharge occurs, the toner is charged to opposite polarity. When toner of different colors is transferred sequentially, the later toner is overlaid onto the toner that has been already transferred on the paper P. The overall potential is increased due to the charge possessed by the toner layer itself and the electrostatic capacitance generated by the toner layer, causing generating a discharge within the toner layer to charge the upper layer to a negative polarity.
More specifically, as shown in FIG. 3( a ), a toner image (of positive polarity) 71 on each of the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C is transferred onto a toner image 70 of a positive polarity onto the paper (not shown), at corresponding transfer nip portion TP which is the position at which the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C face the transfer rollers 66 , 67 , 68 , and 69 respectively, as the paper is conveyed to the left in the figures by the paper conveyor belt 6 . Thus, a layered toner image 72 as shown in FIG. 3( b ) is formed.
In transferring, a discharge (separation discharge) occurs within the toner image 72 , due to the charges possessed by the toners. As a result, a reverse-charged toner image 73 whose upper layer portion is charged to the polarity (negative polarity) opposite to the regular charge polarity (positive polarity), is created as shown in FIG. 3( a ). Even if the reverse-charging does not occur after the paper has passed the transfer nip portion TP, it is possible that reverse-charging could occur at the next transfer position when the next color is transferred to the paper. In other words, the amount of charge (potential) of the toner image is increased since the charge is imparted to the toner from the photosensitive drum 3 during the transfer. The reverse-charging occurs easily, especially when the transfer bias is applied, as the amount of charge on the toner image increases. This consideration can help explain the results of experiments.
Further, when the four developing units 51 BK, 51 M, 51 Y, and 51 C corresponding to four colors performs development sequentially, the magenta toner from the second developing unit 51 M, which has been overlaid on the black toner from the first developing unit 51 BK, is reverse-transferred to the third developing unit 51 Y, as shown in FIG. 4 . Similarly, the magenta toner and yellow toner from the second and third developing units 51 M and 51 Y, which have been overlaid on the black toner from the first developing unit 51 BK, are reverse-transferred to the fourth developing unit 51 C. It is determined that the second toner (magenta) and third toners (yellow) that are overlaid on the first black toner is reverse-transferred to the fourth developing unit 51 C much larger than the first toner (black). Therefore, the first toner (black) has little adverse effect concerning reverse transfer to the second and subsequent developing units 51 M, 51 Y, and 51 C.
By the way, muddying that is generated when the black toner is reverse-transferred has much effect on the image quality than muddying that is generated when the other colors (magenta, yellow, and cyan) are reverse-transferred. On the other hand, as is clear from FIG. 4 , the toner that is reverse-transferred most easily is not the toner in the lowermost layer on the paper P but the toner in the second and subsequent layers that are overlaid thereon.
In the present embodiment, the black toner from the first developing unit 51 BK is transferred to the paper firstly, as described previously. Since the black toner that has much effect on the muddying is transferred firstly, the muddying caused by the black toner is suppressed, causing the image quality to be improved.
Substantially spherical particles that have a high fluidity and good transferability are used as the toner in the present embodiment. If the black toner that has above-described features is transferred onto the paper at the end of mixed-color black development, the black toner that has adhered to the uppermost layer is repulsed by the electrical field that is generated by the toner in the lower layers, due to the extremely high fluidity of the toner. As a result, the colors of the other toners are exposed, making it impossible to form a high-quality black image. However, the image-forming device according to the first embodiment can prevent this problem since the black toner is transferred onto the paper firstly.
With the simultaneous development/cleaning method (otherwise known as the cleanerless method) used in this embodiment, which necessitates reliable recovery of waste toner in the developing units without using any special cleaner, the effects of reverse transfer are greater than in a configuration in which a dedicated cleaner for recovering waste toner is provided. The yellow toner is transferred onto the paper thirdly in the present embodiment, since the toner that is transferred onto the paper thirdly is most likely to be reverse-transferred to the fourth developing unit 51 C. Since the image quality with yellow toner is not as obvious as that with the other colors of toner (black, magenta, and cyan), the effects of reverse transfer is suppressed, even when the simultaneous development/cleaning method is used.
The description now turns to a second embodiment of this invention. Since the configuration of the image-forming device according to the second embodiment is basically the same as that of the first embodiment, further description of components that have the same reference numbers as those in the first embodiment is omitted and the description below concerns only differences from the first embodiment. In the second embodiment, similar to the first embodiment, the black toner is developed onto the paper P firstly, then the magenta, yellow, and cyan non-black toners are developed in the second to fourth places.
In the second embodiment, the total developer amount of the second and third toners (magenta and yellow) is less than the developer amount of the black toner in a mixed-color black development. More specifically, the amounts of each of the magenta, yellow, and cyan toners are equal and less than 50% with respect to 100% of black toner. The developer amount could be adjusted by giving the exposure devices 41 to 44 image data to form the latent electrostatic image of a density (dot spacing) corresponding to the developer amount (%) for each toner on the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C. In other words, the developer amount is determined by a difference in density (dot area) of each color with respect to the region in which the black-colored image is formed on the paper P.
As described above, the amount of toner from the second developing unit 51 M and third developing unit 51 Y that is reverse-transferred to the fourth developing unit. 51 C is larger than the amount of toner from the fourth developing unit 51 C. However, the image-forming device according to the second embodiment restrains the total developer amount of the second and third toners (magenta and yellow) in mixed-color black development, thus preventing the effects of reverse transfer.
While the invention has been described in detail with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.
For example, the black-colored image may be formed by monochromatic black development with a single color of black toner. Such a case, the quality of the black-colored image formation is slightly degraded but deterioration of the quality due to reverse transfer can be prevented.
Only the black toner may be of a substantially spherical form, though all of the toners are of a substantially spherical form in the first embodiment.
The cyan toner is developed by the second developing unit and the magenta toner is developed by the fourth developing unit. Note that the toner of the fourth developing unit is preferably the toner that has the largest amount of toner adhering per unit area (M/A) of the corresponding photosensitive drum. This puts the largest reverse transfer to the fourth developing unit and can minimize the amount of reverse transfer of developer due to the second and third developing units.
The yellow toner may be developed by the second developing unit. It should be noted, however, that yellow toner is preferably used as the third developer, since the large amount of the toner from the third developer is reverse-transferred to the fourth developing unit.
In the above-described embodiments, an image-forming device that uses a “direct transfer method” is described, wherein a visible image (developer image) formed on each photosensitive drum 3 is directly transferred onto the paper P as the transfer recipient. However not limited thereto, an “intermediate transfer method” may be used for the image-forming device, wherein after the visible image formed on each photosensitive drum is transferred to an intermediate transfer body such as an intermediate transfer belt or an intermediate transfer drum as the transfer recipient (primary transfer), the image is transferred from the intermediate transfer body to paper (recording recipient). An OHP sheet may be used instead of the paper P. In addition, not limited to the tandem method, a four-cycle method in which each developing unit forms developer images on a common photosensitive drum can also be used.
A complex machine that is provided with a facsimile, a printing function, or scanner function may be used instead of the printer such as the color laser printer 1 . The laser printer 1 may be provided with cleaning rollers 111 - 114 to clean up the photosensitive drums 3 BK, 3 M, 3 Y, and 3 C, as shown in FIG. 5 .
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An image-forming device includes 1st to N th image bearing members, 1st to N th developing units provided in one-to-one correspondence with the 1st to N th image bearing members, and a transfer unit. N is an integer number equal to or greater than two. The 1st to N th image members have 1st to N th surfaces respectively. The 1st to N th electrostatic latent images are formable on the 1st to N th surface respectively. The 1st to N th developing units have 1st to N th monochromatic developers respectively. The 1st monochromatic developer is of monochromatic black and has a toner particle substantially spherical in shape. The 1st to N th developing units develop the 1st to N th electrostatic latent images with the 1st to N th monochromatic developers respectively in order to form 1st to N th developer images respectively. The transfer unit transfers sequentially the 1st to N th developer images to a recipient in a superimposed manner in order of the 1st to N th developer image.
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FIELD AND BACKGROUND OF THE INVENTION
This invention relates to sewing machines in general and, in particular, to a new and useful stitch setting device for adjusting the length of stitch which is sewn by a sewing machine.
A stitch setting device is known from German Pat. No. 1,027,970, in which a manually rotatable cam disc is provided as the setting member, and has a recess which, beginning from a zero position, grows uniformly larger to both sides of a concentric zero line. The curved surfaces of the recess form stop faces for a contact pin which is secured to a manually pivotable support and is connected through a multi-member linkage to the feed elements of the sewing machine. A tension spring acting on the support holds the pin in contact with the outer curved face whose radial distance from the concentric zero line determines the forward feed step. To reverse the sewing direction, the support is pivoted and the pin is brought into contact with the inner curved face. Since in either of the two positions, the contact pin is radially equally spaced from the concentric zero line, the feed steps in the forward and backward directions are equal to each other.
In order to secure a seam, the threads are frequently locked on both ends of the seam by sewing a short length alternately forwardly and backwardly, two or three times. To ensure a continuous operation, the forward sewing must be reversed to the backward sewing and vice versa as quickly as possible. For this purpose, it is known to connect the support carrying the contact pin to an air cylinder and to determine the instant of reversal, for example, by means of photocell controls or stitch counters.
However, experience has shown that quick reversals of the stitch setting device cause a premature wearing down of the contact pin and the stop faces of the cam disc. In addition, the train members of the linkage between the air cylinder and the contact pin which transmit the setting forces from the air cylinder up to the respective stop face of the cam disc are exposed to high bending and buckling stresses caused by the abrupt braking during the motion reversal, and thus, may deform or even break.
SUMMARY OF THE INVENTION
The present invention is directed to a stitch setting device which is suitable for quickly reversing the feed direction and in which the members of the transmission train are exposed to only small loads, in spite of the high switching speed.
In accordance with the invention, a stitch setting device is provided for adjusting the length of stitch by varying the magnitude of movement of the dog which engages the material which is being fed. The setting device includes a movable contacting member connected to the stitch movement control mechanism and which is movable between two end positions so as to adjust the workpiece dog shifting mechanism and thus vary the amount of movement of the material during each feed movement. The construction includes setting members which are disposed in the path of movement of the contacting member and on respective opposite sides thereof. The setting members are positioned by a control which is effective to move each of them in respective opposite directions so as to vary their position in respect to the contacting member and to provide stop limiting elements limiting the movement of the contacting member in each direction.
Due to the provision that the setting member or the contacting member of the stitch setting device is connected to the piston rod, and the respective other member to the housing of the pressure fluid operated cylinder, the cylinder and the setting and contacting members form a constructional unit. In this way, the functions hitherto performed in separate devices, namely, of producing a setting force and displacing a member of the stitch setting device relative to the other member, are now performed by a single interconnected mechanism. This is advantageous in that the number of component parts of the transmission train for reversing the feed direction is smaller than in the prior art devices.
Since the setting and contacting members are now connected to the piston rod or to the housing of the pressure fluid operated cylinder and the setting member is designed as two stop elements which are disposed concentrically of the longitudinal axis of the cylinder and are displaceable in opposite directions, both the setting motion of the setting member and the displacement of one member relative to the other during the feed direction reversal take place in the direction of the longitudinal axis of the pressure fluid operated cylinder. In consequence, the setting member and the contacting member remain axially aligned in any position and may be designed in a manner such that they always come into a surface contact with each other. Since the specific contact pressure produced is then only small, there is no risk that the setting or contacting member would be deformed, not even at high switching speeds.
According to a development of the invention, the stop elements are designed as two axial displaceable end parts limiting the travel path of the piston, with the piston acting as the contacting member. Due to the provision of using the piston of a pressure fluid operated cylinder producing the setting force directly as the contacting member of a stitch setting device, any connecting element between the piston and a separate contacting member is omitted and the number of component parts to be moved during the reversal of the feed direction is reduced to a minimum.
The strong impact forces produced as the piston abruptly impinges on the stop faces of the end parts are directly taken up by the end parts and transmitted through the housing of the pressure fluid operated cylinder and the component parts connecting the cylinder to the sewing machine, to the casing of the sewing machine. There is no risk of overstressing the transmission members driven by the piston rod, by the impact forces produced during the reversal.
In accordance with a further development of the invention, the end parts are guided in a cylinder sleeve and are provided with oppositely handed threads and are connected to each other by means of a setting collar which also has oppositely handed threads and is axially fixed relative to the cylinder sleeve. The end parts and the setting collar thus forms a closed casing encircling the cylinder sleeve and are variable in size. Since the setting collar is provided with a lefthand thread and a righthand thread for the two end parts, upon turning the setting part, the end parts are moved simultaneously in opposite directions. If the righthand and lefthand threads have equal pitches, the two end parts are equally spaced from a zero position in any set position, so that upon a reversal of the feed direction, the feed stop remains unchanged.
The axial position of the setting collar relative to the cylinder sleeve is advantageously insured by a holding ring which is secured to the cylinder sleeve and engages an annular groove of the setting collar.
To fix the end parts radially relative to the cylinder sleeve, guide pins are provided which extend parallel to this cylinder sleeve and are firmly fitted in the holding ring to project to both sides thereof. Guide bores receiving the guide pins are provided in the end parts.
In another embodiment of the stitch setting device, the stop elements are designed as two stop discs which are carried on the piston rod of the pressure fluid operated cylinder and are displaceable between two cross-bars connected to the cylinder housing and acting as a contacting member. In this embodiment, the setting and contacting members are provided outside of the housing of the pressure fluid operated cylinder, so that, in such an application, a conventional cylinder piston system may be used. Since, in this case, the contacting member is connected to the housing of the pressure fluid operated cylinder, and the setting member is connected to the piston rod, the impact forces produced at the reversal of the feed direction are transmitted to the cylinder housing and then through the connecting component parts to the casing of the sewing machine.
In still another embodiment of the invention, the stop elements are designed as two stop discs which are carried by the piston rod of the pressure fluid operated cylinder, and a contacting piece forming the contacting member is provided on the casing of the sewing machine at a location between the discs. In this embodiment, a conventional cylinder piston system may again be used. The contacting member is connected to the housing of the pressure fluid operated cylinder indirectly through the sewing machine casing. The advantage of this design is that, upon reversing the speed direction, the impact forces produced which act on the contacting member are directly transferred to the casing of the sewing machine.
In the last two embodiments discussed above of the stitch setting device, in order to adjust the distance between the stop elements or stop discs, and thus, between the stop faces cooperating with the contacting member, the stop discs are provided with oppositely handed internal threads and are engaged on a correspondingly oppositely threaded, axially fixed sleeve which is mounted for rotation on the piston rod, and are secured against rotation.
Accordingly, it is an object of the invention to provide a sewing machine which includes a material engaging part engageable with a workpiece material to selectively feed the workpiece material in forward and reverse directions in respect to a sewing needle for sewing stitches of selected lengths in the workpiece and which includes a shifting mechanism for driving the material engaging member which is adjustable for varying the amount of movement of the material engaging member wherein the improvement comprises a stitch setting device for adjusting the length of the stitch by varying the magnitude of movement of the material engaging part and includes a movable contacting member connected to the shifting mechanism which is movable between two end positions to adjusting the shifting mechanism by a selected amount so as to vary the amount of movement of the material engaging part and further including first and second setting members disposed in the path of movement of the contacting member on respective opposite sides of the contacting member and setting member positioning means connected to each of the setting members so as to move them simultaneously in respective opposite directions and to vary the end position of movement of the contacting member in accordance with the adjusted position of the setting member.
A further object of the invention is to provide a sewing machine with an improved stitch setting device which is simple in design, rugged in construction and economical to manufacture.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is an elevational view of a sewing machine constructed in accordance with the invention;
FIG. 2 is a perspective view of a first embodiment of a stitch setting device and of the feed mechanism of the sewing machine;
FIG. 3a is a sectional view of the pressure fluid operated cylinder of the stitch setting device, the upper portion showing the relative position of the end parts of the cylinder if a stitch length zero is set;
FIG. 3b is a view similar to FIG. 3a showing the ends parts in their position if a relatively long stitch length is set;
FIG. 4 is an elevation, partly in section, of a second embodiment of the stitch setting device; and
FIG. 5 is a view similar to FIG. 4 showing a third embodiment of a stitch setting device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in particular, the invention embodied therein in FIGS. 1 through 5, comprises, a sewing machine which includes a material engaging part or dog 8 which is engageable with a workpiece material in order to selectively feed it in either a forward or reverse direction so as to bring it in engagement with a reciprocating needle 7 for sewing stitches of selected lengths in the workpiece.
The horizontal movement of dog 8 is controlled by a shifting mechanism, generally designated 13', which includes a shifting eccentric 13 which is connected to dog 8 by a linkage mechanism and which is adjustable for varying the amount of movement of the dog horizontally or backwardly and forwardly.
In accordance with the invention, a stitch setting device, generally designated 28' is connected to shifting mechanism 13' so as to provide means for adjusting the length of stitch by varying the magnitude of movement of the dog 8 in the backward and forward directions. The stitch setting mechanism comprises a contacting member, generally designated A which is connected to the shifting mechanism 13' and which is movable between two end positions in order to adjust the shifting mechanism by a selected amount so as to vary the movement of the dog 8 by a selected amount.
The arrangement includes setting members, generally designated 31 and 32 and comprise first and second elements disposed in the path of movement of the contacting member on respective opposite sides thereof and limiting the movement of the contacting member to a movement in which the contacting member moves into engagement with a respective one of the setting members. The position of the setting members 31 and 32 is controlled by positioning means which is connected to the setting members and which is movable in a selected direction to move the setting members in respective directions so as to vary the end position of the movement of the contacting member in accordance with the adjusted position of the setting members which engage with the contact member in the respective end positions.
The sewing machine 1 comprises a lower casing 2, a post 3, an arm 4, and a head 5. The head 5 supports a needle bar 6 which is mounted in a manner known per se for reciprocating motion up and down and carries a thread guiding needle 7.
The sewn material is fed by means of a four motion feed dog 8 which is secured to a feed bar 9. Feed bar 9 has a forked end 9a engaging over a lifting eccentric 11 which is carried by a shaft 10. As shaft 10 rotates, eccentric 11 imparts to the feed dog 8 the vertical motion component necessary for executing the four motion sequence.
To produce the horizontal feed motion of feed dog 8, a shifting eccentric 13 is secured to a shaft 12 and is embraced by an eccentric bar 14. Two links 16 and 17 are hinged to eccentric bar 14 by means of a bolt 15. Link 16 is pivoted by means of a bolt 18 to a crank 19 which is secured to a setting shaft 20. Link 17 is pivoted by means of a bolt 21 to a crank 22 which is secured to a shaft 23. A forked crank 24 is secured to shaft 23 and hinged to feed bar 9.
A crank 25 is secured to setting shaft 20. Hinged to crank 25 is a forked head 26 which is secured to the piston rod 27 of a pressure fluid operated cylinder 28. Cylinder 28 is provided with a cylinder sleeve 29 which is open on both ends and in which the piston 30 firmly secured to piston rod 27 is guided. The ends of the cylinder sleeve 29 are closed by two caplike end parts 31 and 32. Each of end parts 31 and 32 is provided with a relatively deep annular slot 33, 34 into which cylinder sleeve 29 can penetrate. The portions extending into sleeve 29 of end parts 31, 32 are sealed against the sleeve by means of seal rings 35, 36, so that the sleeve and the end parts 31, 32 form together a closed pressure-tight cylinder chamber 37. The front faces of the portions of end parts 31, 32 extending into cylinder sleeve 29 form stop faces 38, 39, for piston 10.
End part 31 is provided with a tapped connection bore 40 for receiving a tube connection (not shown), so that a pressure fluid tube can be attached to end part 31. Connection bore 40 opens into an axially extending bore 41 which, in turn, opens into cylinder chamber 37. The diameter of bore 41 is sufficiently dimensioned to ensure a rapid flow of the pressure fluid between the wall of bore 41 and the piston rod 27 extending therethrough. Compressed air is preferably used as the pressure fluid. At the free end of end part 31, where piston rod 37 extends to the outside, bore 41 is sealed by a seal ring 42.
End part 32 is provided with a connection bore 43 for receiving a tube connection (not shown), so that a pressure fluid tube can be attached to end part 32. Connection bore 43 opens into an axially extending blind bore 44 which, in turn, opens into the cylinder chamber 37.
On its end portion adjacent stop face 38, end part 31 is provided with a lefthand threaded shoulder 45. End part 32 is provided on its end portion adjacent stop face 39 with a righthand threaded shoulder 46. Both threads have the same pitch. The two end parts 31, 32 are connected to each other by a setting collar 47. End parts 31, 32 and setting collar 47 form the housing 73 of a pressure fluid operated cylinder 28.
Setting collar 47 comprises a bearing ring 48 and an annular insert 49 which is firmly fixed to ring 48 and secured against rotation therein. Bearing ring 48 is provided with a righthand inner thread cooperating with threaded shoulder 46, and insert 49 is provided with a lefthand inner thread cooperating with threaded shoulder 45. An annular groove 52 is provided in bearing ring 48 adjacent the end of insert 49.
A holding ring 55 engaging annular groove 52 is mounted on cylinder sleeve 29 and is axially fixed by means of two guard rings 53, 54. Setting collar 47 is axially secured against cylinder sleeve 29 by holding ring 55. A plurality of guide pins 56 which extend parallel to the piston rod 27 and to both sides of holding ring 55 are firmly fitted in holding ring 55, to be received in guide bores 57, 58 of end parts 31, 32. Guide pins 56 extending into guide bores 57, 58 produce the effect that the two end parts 31, 32 cannot be turned relative to each other and can only be displaced in the axial direction.
The effect of providing lefthand and righthand threads on the shoulders 45, 46 and in setting collar 47 is that upon turning collar 47, end parts 31, 32 are displaced in mutually opposite directions, toward each other if the collar is turned in one direction, and apart from each other if the collar is turned in the other direction. In the upper part of FIG. 3, the minimum possible distance between the two end parts is shown. In this case, piston 30 is in its zero position. The lower part of FIG. 3 shows end parts 31, 32 relatively widely spaced apart, with both stop faces 38, 39 being at the same distance from the zero position.
A receiving ring 59 which is axially fixed by means of a shoulder on ring 48 and a guard ring 61 is rotatably mounted on bearing ring 48. An angle piece 62 carrying an indicator pin 63 is secured on the outside to receiving ring 59. Indicator pin 63 is associated with a graduation or scale 64 provided on the outer surface of end part 32 so that the position of end part 32 relative to the axially fixed retaining ring 59 is indicated. The recess 65 of receiving ring 59 in which guard ring 61 is accommodated is closed by means of an annular disc 66. In addition, as shown in FIG. 2, two radially projecting bolts 67 and 68 are secured to the outside of receiving ring 59. By means of the bolts 67, 68, pressure fluid operated cylinder 28 is hinged to ribs 69, 70 which form portions of a mounting plate 71. Mounting plate 71 is secured to the post 3 of sewing machine 1 and covers a recess (not shown) provided in the wall of the post. Mounting plate 71 is provided with a window 72 through which setting collar 47 partly protrudes beyond the outside of mounting plate 71, so that it can easily be actuated by the operator.
In the above sewing machine, the pressure fluid operated cylinder 28 embodies the stitch setting device for determining the length of the feed step and the feed direction of feed dog 8. The setting member, generally designated S of the device is embodied by the two oppositely displaceable end parts 31 and 32, while the contacting member A is embodied by the piston 30.
In the embodiment of FIG. 4, a stitch setting device comprises a double-acting air cylinder 80 of conventional design of which the housing 81, piston 82, and piston rod 83 are shown in FIG. 4. Air cylinder 80 is screwed by means of a threaded shoulder 84 into a cross-bar 85. Cross-bar 85 is hinged by means of two bolts 86 to the casing (not shown) of the sewing machine. By means of two stay bolts, 87, 88, a cross-bar 89 is secured to and spaced from cross-bar 85. Cross-bars 85 and 89 and stay bolts 87, 88 together form a rigid frame. The portion of piston rod 83 extending outside of housing 81 has a reduced diameter. On this portion of piston rod 83, a threaded sleeve 90 is mounted for rotation. The external thread of threaded sleeve 90 is divided in two portions 91, 92, one being a lefthand thread and the other being a righthand thread. The free end of piston rod 82 terminates with a threaded stud 93 of smaller diameter. Threaded sleeve 90 is axially fixed by means of a nut 94 screwed onto threaded stud 93, and a washer 95.
Between the two cross-bars 85, 89, threaded sleeve 90 carries two stop discs 96, 97, each on one of the two portions 91, 92, which are provided with corresponding internal threads. Each of the stop discs 96, 97 is provided with two recesses 98 through which stay bolts 87, 88 extend. A setting wheel 99 is firmly fitted to the lower end of threaded sleeve 90. A forked head 100 is screwed to the free end of threaded stud 93. The forked head is hinged to the crank 25, as described in connection with the first embodiment.
In this stitch setting device, setting member S' is embodied by the two oppositely displaceable stop discs 96, 97 while the contacting member A' is embodied by the two cross-bars 85, 89.
In still another embodiment, the stitch setting device comprises a double-acting air cylinder 110 of conventional design of which the housing 111, piston 112, and piston rod 113 are shown in FIG. 5. Air cylinder 110 is provided with a threaded shoulder 114 by which it is screwed into a bracket which is firmly screwed to the casing wall 116 of the sewing machine. A portion 111 of piston rod 113 extending outside housing 111 has a smaller diameter. On the portion 111 of the piston rod 113, a threaded sleeve 117 is mounted for rotation.
The external thread of threaded sleeve 117 is divided in two portions 118, 119 of which one is a lefthand thread and the other a righthand thread. The free end of piston rod 113 terminates with a threaded stud 120 of smaller diameter. Threaded sleeve 117 is axially fixed by means of a nut 121 screwed onto threaded stud 120 and a washer 122.
Threaded sleeve 117 carries two stop discs 123, 124, one on each of the two portions 118, 119, which are provided with corresponding internal threads. Each of stop discs 123, 124 is provided with one recess 125. A guide pin 126 secured to bracket 115 extends through recesses 125, so that stop discs 123, 124 are secured against rotation.
A contacting piece 127 fixed to casing wall 116 and provided with a recess for threaded sleeve 117 projects into the space between the two stop discs 123, 124. A setting wheel 129 is secured to the lower end of threaded sleeve 117. A forked head 130 is firmly screwed to the free end of threaded stud 120. With an interconnected link 131, forked head 130 is hinged to crank 25 as explained in connection with the first embodiment.
In this stitch setting device, the setting member S" is embodied by the two oppositely displaceable stop discs 123, 124, while the contacting member A" is embodied by the contacting piece 127.
The stitch setting device operates as follows:
In the embodiment shown in FIGS. 1 to 3, the zero position of piston 30, corresponding to the minimum possible distance between end parts 31, 32, the stitch length O is set. In this position, the axes of bolts 18, 21 are aligned with each other so that, with the sewing machine 1 on, links 16, 17 execute only pivotal motions about the respective bolts 18 and 21, while crank 22 stands still. In consequence since shaft 23 does not move either, feed dog 8 only executes the periodical up and down movements caused by lifting eccentric 11, but no feed movements.
To adjust a feed length, setting collar 47 is turned whereby end parts 31 and 32 are displaced in mutually opposite directions, in this instance apart from each other, so that cylinder chamber 47 and the path of stroke of piston 30 are extended. To sew forward, the piston surface facing end part 32, is loaded with compressed air, whereupon piston 30 applies against stop face 38 of end part 31. Thus, upon turning setting collar 47, piston 30 is displaced and, through piston rod 27, crank 25 is pivoted and shaft 20 is turned. This rotary motion of shaft 20 causes pivoting of crank 19, so that bolt 18 embodying the axis of rotation of link 16 is displaced relative to bolt 21 forming the axis of rotation of link 17. During the oscillatory motion of bolt 15 caused by eccentric bar 14, link 16 executes a purely pivotal motion about bolt 18, while link 17 also executes a relative motion about shaft 23, in addition to the pivoting motion about bolt 21. This relative motion is transmitted as pivotal motion of crank 22 to shaft 23 and to forked crank 24 by which feed motions are imparted to feed dog 8 through feed bar 9.
By turning setting collar clockwise or counter clockwise, the position of piston 30 relative to, or its distance from, the zero position is increased or reduced, so that the length of the feed step of feed dog 8 and the stitch length of the seam to be sewn is adjusted. The set stitch length can be read on a graduation 64 provided on end part 32, by means of the fixed indicator pin 63.
To sew backward, the space at the piston side facing end part 32 is vented and the surface of piston 30 facing end part 31 is loaded with compressed air, whereby piston 30 is displaced from end part 31 to end part 32 and impinges on stop face 39. Thereby, through piston rod 27, crank 25, and setting shaft 20, crank 19 is pivoted to the effect that bolt 18, which, during the forward sewing, was laterally behind bolt 21 as viewed in FIG. 2, moves through the position of alignment into a position laterally in front of bolt 21. In this way, the oscillatory motion of link 17 caused by shifting eccentric 13 is performed in phase opposition and feed dog 9 executes its feed motion in the backward direction. Since stop face 39 of end part 32 is always exactly equally spaced from the zero position as stop face 38 of end part 31, upon a reversal of the sewing direction, the feed length and the stitch length remain unchanged.
To perform the sewing operation without interruption or loss of time, the seam locking reversal or switching over of the feed direction must be effected very quickly. Consequently, piston 30 is moved from one to the other end part 31, 32 at high speed. As piston impinges on stop face 38, 39, its speed is abruptly braked down to zero and the kinetic energy is dissipated. The produced strong impact forces are taken up directly by the respective end part 31, 32 and transmitted, through setting collar 47, receiving ring 39, bolts 67, 68, and mounting plate 71, into the post 3 of sewing machine 1. Since these component parts are not moved during the feed reversal operation, they can be so dimensioned that their wear is prevented even with frequent reversals of the feed direction. On the other hand, the impact forces caused by the braking of piston 30 do not produce any effect on the transmission parts which are provided between the pressure fluid-operated cylinder 28 and the feed mechanism and which are moved upon a displacement of piston 30, so that there is no risk of overstressing these parts.
Since the stop faces 38, 39 are formed by relatively large annular surface areas and the front sides of piston 30 are flat, only a small specific contact pressure is produced at the impact of the piston on end parts 31, 32 and no risk of a premature wear of these component parts is incurred.
In the embodiment of FIG. 4, with stop discs 96, 97 at the maximum possible distance from each other, and resting against both the upper crossbar 85 and the lower crossbar 89, piston 82 can no longer be moved. In this position of stop discs 96, 97, the stitch length zero is set.
To set a feed, setting wheel 99 is turned, so that stop discs 96, 97 are moved toward each other. If a forward sewing is intended, the upper side of piston 92 is loaded with compressed air, with the effect that stop disc 97 applies against crossbar 89. By turning setting wheel 99, the air-loaded piston 82 is displaced whereby crank 26 is pivoted by means of piston rod 83. As already mentioned in connection with the first embodiment, a pivotal motion of crank 25 has the effect of adjusting a feed length of feed dog 8. By turning setting wheel 99 clockwise or counterclockwise, the distance of stop discs 96, 97 from their zero position and thereby the feed step of feed dog 8 determining the stitch length are reduced or increased.
If backward sewing is wanted, the upper side of piston 82 is vented, and the underside is exposed to compressed air, so that stop disc 97 is lifted from crossbar 89 and stop disc 96 applies against crossbar 85. Thereby, through piston rod 83, pivotal motion is imparted to crank 25 in the same way as in the first embodiment and the feed direction of feed dog 8 is reversed.
The impact forces produced at the reversal of the feed direction as stop discs 96, 97 abruptly impinge on crossbars 86, 89, are transmitted through housing 81 and bolts 86 to the casing of the sewing machine, and absorbed. These forces do not produce any effect on crank 25 nor on the farther component parts of the transmission, so that no risk of overstressing is incurred.
In the embodiment of FIG. 5 with the stitch setting device, a stitch length zero is set if stop discs 123, 124 are at a minimum possible distance from each other and apply against contacting piece 127 from both sides.
To set a feed, setting wheel 28 is turned so that stop discs 123, 124 move apart from each other. If forward sewing is desired, the upper side of disc 112 is exposed to compressed air, so that stop disc 123 comes to apply against contacting piece 127. By turning the setting wheel, piston 112 loaded with compressed air is displaced and, through piston rod 113 and link 131, crank 25 is pivoted. As already mentioned in connection with the first embodiment, a pivotal motion of crank 25 produces the effect of adjusting the feed step of feed dog 8. By turning setting wheel 25 clockwise or counterclockwise, the distance of stop discs 123, 124 from their zero position and, thereby, the feed step of feed dog 8 determining the stitch length, are reduced or increased.
The impact forces produced at the reversal of the feed direction by the abrupt impingement of stop discs 123, 124 on contacting piece 127 are transmitted to, and taken up by, casing 116 of the sewing machine partly directly through contacting piece 127 and partly through housing 111 and bracket 115. Thus, in this embodiment again, the impact forces do not produce any effect on crank 25 or on the following component parts of the transmission.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
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A sewing machine includes a material engaging part such as a dog which is engageable with a material workpiece to selectively feed it in a forward and a reverse direction. In addition, the sewing machine includes the usual mechanism for raising and lowering the dog so as to complete an advancing or reverse movement of the material. The dog is driven preferably by a mechanism which includes an eccentric which may be adjusted so as to vary the length of horizontal feeding movement of the dog while the elevational changes of the dog remain constant by a separate feeding control mechanism. The magnitude of movement of the dog is controlled in accordance with a stitch length to be sewed by a stitch setting device which includes a movable contacting member which is connected to the eccentric mechanism and is movable between two end positions in order to adjust by a selected amount the movement of the eccentric in driving the dog by a selected amount. The device also includes first and second setting members arranged on respective sides of a contacting member which may, for example, be in the form of a fluid operated piston and a setting member positioning means is connected to the two setting members so as to move them simultaneously in respective opposite directions and position them on respective opposite sides of the contacting member or piston so as to control the end positions of movement of the piston during the operation of the sewing machine. The piston rides in a fluid cylinder and fluid pressure may be applied to respective sides thereof for shifting the position of the piston for the purposes of reversing the direction of feeding movement of the material being sewn.
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[0001] This application is a continuation-in-part of application Ser. No. 13/289,670, filed Nov. 4, 2011.
BACKGROUND
[0002] This invention relates to pipe preparing tools, and more particularly to novel devices for peeling the outer surface of a polyethylene pipe, even when the outside of the pipe does not have a perfectly circular circumference or uniform diameter.
[0003] It is often necessary to remove a portion of the exterior surface of a pipe prior to welding or otherwise affixing the pipe to a coupling. In an electrofusion process for joining plastic pipes, such as those constructed of polyethylene, it is an absolute requirement. Removal of a portion of the exterior surface of the pipe eliminates oxidation of and impurities in the exterior surface of the pipe, and helps ensure a trouble-free joint.
[0004] Uniform peeling of polyethylene pipes can be a difficult task because the pipes are often already “in the field” and affixed in place, thereby limiting the use of larger, more precise pipe peeling machines. Under these circumstances, a uniform peel can be difficult to achieve. Many pipe peelers require multiple attachments, often to the inside of the pipe being peeled, which lengthens the time required to peel the pipe.
[0005] It is an object of the present disclosure to provide a pipe peeler that will create a uniform peel on the end of a polyethylene pipe.
[0006] It is an object of the present disclosure to provide a pipe peeler that will peel in a spiral pattern on the outer surface of a polyethylene pipe.
[0007] It is an object of the present disclosure to provide a pipe peeler that does not require itself to be anchored to the inside of a pipe for use.
[0008] It is another object of the present disclosure to provide a pipe peeler that has no delicate or easily breakable exposed parts and requires minimal or no cleaning.
[0009] It is another object of the present disclosure to provide a pipe peeler that is small, compactable, and lightweight.
[0010] It is another object of the present disclosure to provide a single pipe peeler that may be used on a wide range of pipe circumferences.
[0011] It is another object of the present disclosure to provide a pipe peeler that can peel a circular or oval pipe.
[0012] It is another object of the present disclosure to provide a pipe peeler that can easily be used “in the field” on an immovable pipe.
[0013] It is another object of the present disclosure to provide a pipe peeler whereby a user can release his or her grip on the peeler and the peeler will remain in place on the pipe.
[0014] It is another objected of the present disclosure to provide a pipe peeler that can operate on pipes that do not have perfectly circular outer circumferences or uniform diameters.
[0015] Various other features, advantages and characteristics of the present invention will become apparent to one of ordinary skill in the art after a reading of the following specification.
[0016] In the displayed embodiments, the pipe peeler comprises a cuboid body, a retractable blade, a chain, means for coupling the chain near the front and back of the body, a means for pulling one end of the chain towards the body (and thereby tightening the chain around a pipe), and a grip. The two connection points of the coupling the chain to the body are offset so that the chain forms a helix when the chain is tightened around a pipe.
[0017] As used herein, the term “chain” is meant to include other devices which may encircle a pipe, including but not limited to cables, belts, cords, ropes, harnesses, clamps, and so on.
[0018] As used herein, the term “chain segment” may to refer to less than an entire chain or the entire chain as disclosed in the specification and claims.
[0019] The particular embodiments described below are proven to uniformly peel polyethylene pipe. However, these embodiments and obvious modifications thereof may also uniformly peel pipes with material properties similar to polyethylene. This disclosure and the claims herein are directed toward peelers for pipe with material properties similar to polyethylene.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a side perspective view of some parts of an embodiment of the invention, with some parts omitted in order to provide a clear view of the parts shown therein;
[0021] FIG. 2A is a side view of the parts of the embodiment of FIG. 1 ;
[0022] FIG. 2B is a top view of the parts of the embodiment of FIG. 1 ;
[0023] FIG. 2C is a front view of the parts of the embodiment of FIG. 1 ;
[0024] FIG. 3A is a side view of the complete embodiment of the invention, in use on a pipe;
[0025] FIG. 3B is a side perspective view of the embodiment of FIG. 3A ;
[0026] FIG. 3C is a side perspective view of the embodiment of FIG. 3A ;
[0027] FIG. 4A is a top view of the embodiment of FIG. 3A ;
[0028] FIG. 4B is a rear view of the embodiment of FIG. 3A ;
[0029] FIG. 4C is a front view of the embodiment of FIG. 3A ;
[0030] FIG. 5 is an exploded view of a portion of the embodiment shown in FIGS. 3A-3C ;
[0031] FIG. 6A is an exploded view of a second embodiment of the invention;
[0032] FIG. 6B is identical to 6 A but identifies additional elements of the second embodiment;
[0033] FIG. 7 is a side cross-section view of the second embodiment of FIGS. 6A and 6B ;
[0034] FIG. 8 is a top view of the second embodiment of FIGS. 6A and 6B , in use on a pipe.
[0035] FIG. 9 is a rear view of the second embodiment of FIGS. 6A and 6B , in use on a pipe.
DESCRIPTION OF EMBODIMENTS
[0036] An embodiment of the pipe peeler surrounding a pipe is shown in FIGS. 3A , 3 B, and 3 C generally at 10 . In all embodiments disclosed, substantially all parts of the pipe peeler may be made of metal but are interchangeable with other materials obvious to those skilled in the art.
[0037] Referring to FIG. 1 , the pipe peeler 10 includes a peeler body 20 . In this embodiment, peeler body 20 is generally cuboid-shaped but other embodiments may take other shapes without adverse effect on the device's functionality.
[0038] Four wheels 28 are attached to the peeler body 20 . The wheels 28 can be bolted or otherwise affixed to the body 20 and each wheel 28 may rotate about a shoulder bolt.
[0039] Grip shaft 24 is affixed to peeler top face 18 , wherein the affixing may be done by a male thread (not shown) on the grip shaft 24 and female thread (not shown) in the peeler body 20 , or other affixing means such as welding or manufacturing the peeler body 20 and grip shaft 24 in one piece. Likewise, grip knob 22 is affixed to grip shaft 24 , using, for example a male thread (not shown) on the grip shaft and a female thread (not shown) in the grip knob, or other means such as welding or manufacturing the knob 22 and shaft 24 as one piece.
[0040] As shown in FIG. 2B , peeler front face 12 includes a holding pin recess 58 . Holding pin 48 is affixed inside holding pin recess 58 and is parallel to peeler front face 12 . As seen in FIG. 1 , one end of holding pin 48 is inside holding pin aperture 72 , while the other end of holding pin 48 may be affixed to the holding pin recess 58 wall opposite holding pin aperture 72 using, for example, a male thread (not shown) on the holding pin end and a receiving female thread (not shown) on holding pin recess 58 wall opposite the holding pin aperture 72 , with, for example, a flathead screwdriver receptor or hex key receptor at the end of the holding pin 48 that is exposed on peeler blade face 16 through holding pin aperture 72 . An alternative to this drawn embodiment is, for example, welding the holding pin 48 in place. The holding pin 48 does not need to be able to rotate when the pipe peeler 10 is in use.
[0041] Peeler back face 14 includes a pivot bar recess 54 . Pivot bar 36 is inside pivot bar recess 54 and is parallel to peeler back face 14 . One end of pivot bar 36 is inside pivot bar aperture 74 , while the other end of pivot bar is inside a recess (not shown) on pivot bar recess 54 wall opposite pivot bar aperture 74 . As shown in FIG. 2A , one of the wheels 28 holds pivot bar 36 in place. Pivot bar 36 should be able to rotate when the pipe peeler 10 is in use.
[0042] Threaded hook shaft 32 goes through hook pivot aperture 76 . Female threaded cylinder 34 affixes to threaded hook shaft 32 . Threaded hook shaft is connected to, or manufactured as one piece with, hook 26 . Cylinder handle 70 is in female threaded cylinder 34 through cylinder apertures 38 . In this embodiment, cylinder handle 70 is held in place inside female threaded cylinder 34 with spring resistance and friction, but may be held in place using other means such as, for example, welding or manufacturing the female threaded cylinder 34 and cylinder handle 70 as one piece.
[0043] Blade body 50 is affixed to peeler body 20 with two blade body bolts 52 threaded through two female threaded receptors (not shown) on peeler top face 18 . Alternatively, blade body 50 may be affixed to peeler body 20 with welding or other means obvious to those skilled in the art.
[0044] Blade shaft 46 goes through blade body 50 through a cylindrical aperture (not shown) in blade body 46 . Blade shaft 46 is attached to blade knob projection 44 . Blade knob projection is attached to blade knob 40 . The opposite end of blade shaft 46 is attached to blade stop 56 . Blade stop 56 is attached to blade 30 . Alternatively, both blade 30 and blade stop 56 may be attached to blade shaft 46 directly with, for example, a male thread on blade shaft 46 and female threads in blade stop 56 and blade 30 .
[0045] Blade stabilizing pin 62 is affixed to blade shaft 46 . Inside blade body 50 a compressed spring 90 pushes against blade stabilizing pin 62 such that the natural tendency of the spring 90 is to push blade stop 56 and blade 30 away from blade body 50 . The compressed spring 90 may surround blade shaft 46 .
[0046] Blade stabilizing pin 62 may move along the major axis of blade stabilizing elliptical opening 60 , allowing blade 30 to be in a raised or lowered position. However, blade stabilizing pin may not move on the minor axis of blade stabilizing elliptical opening 60 , thereby preventing blade shaft 46 and blade 30 from rotating.
[0047] As shown in FIG. 2C , when blade knob projection 44 presses against blade body top face 78 , blade 30 does not extend downward beyond wheels 28 . As shown in FIG. 3B , when blade knob projection 44 is in blade body notch 42 , blade 30 is fully extended and may extend beyond wheels 28 and press against a pipe 68 . Thus, blade 30 may be raised by turning blade knob 40 clockwise and lowered by turning blade knob 40 counterclockwise.
[0048] Before wrapping chain 64 around a pipe 68 , blade 30 is in raised position, i.e., blade knob extension 44 is resting against blade body top face 78 .
[0049] Turning now to FIGS. 3A , 3 B, and 3 C, one end of a chain 64 is attached to peeler body 20 . Chain 64 is wrapped around a pipe 68 , and hook 26 threads through chain 64 at a point that enables chain 64 to wrap as tightly as possible around pipe 68 . As seen in FIG. 3B , at this point pipe peeler 10 may be positioned on pipe 68 such that blade 30 is positioned over the pipe end 80 to be peeled.
[0050] Chain 64 is further tightened by turning cylinder handle 70 , thereby pulling threaded hook shaft 32 and hook 26 into female threaded cylinder 34 and pulling chain 64 toward peeler body 20 . Tightening is continued until pipe peeler 10 is immobile on pipe 68 and will not slide off of pipe even when pipe peeler 10 is not being held by a user.
[0051] If the length of chain 64 is much larger that pipe 68 circumference and the part of chain 64 not being used extends far beyond point at which hook 26 threads through chain, a magnet 66 at end of chain 64 will attach excess loose chain 64 to chain 64 surrounding pipe 68 .
[0052] Once chain 64 is fully tightened around pipe 68 , blade knob 40 may be turned such that blade projection 44 rests in blade body notch 42 thereby allowing blade 30 to extend downward and contact pipe, as seen in FIG. 3B .
[0053] As shown in FIG. 4A , chain 64 is slightly offset where the chain end connected to holding pin 48 is closer to pipe end 80 and the chain point connected to hook 26 is slightly farther away from pipe end 80 .
[0054] Once chain 64 is fully tightened and blade 30 is extended to press against pipe 68 , grip knob 22 is pushed in a direction tangential to pipe circumference, toward peeler front face 12 , such that pipe peeler 10 rotates around pipe 68 thereby allowing blade 30 to peel the outer surface of the pipe 68 .
[0055] Due to the slightly giving and springy nature of polyethylene pipe, the pressure of the chain 64 against the pipe 68 will cause the chain 64 to press a temporary “track” into in the pipe 68 . As pipe peeler 10 is rotated around pipe 68 , the chain 64 “track” will direct the pipe peeler 10 to move down the pipe 68 in a uniform spiral, thereby allowing the blade 30 to create a uniform peel. The chain leaves none, or very minimal, permanent “track” on the pipe.
[0056] In this embodiment, the width of the blade 30 is greater than the helical pitch, i.e., greater than the distance that the pipe peeler 10 travels away from the pipe end 80 during one full rotation of the pipe peeler 10 around the pipe 68 .
[0057] Once the pipe 68 has been peeled a satisfactory amount, blade knob 40 may be turned clockwise to raise blade 30 . Cylinder handle 70 is turned to allow hook 26 to move away from female threaded cylinder 34 , thereby allowing chain 64 to loosen and enabling pipe peeler 10 to be removed from pipe 68 .
[0058] A second embodiment of a pipe peeler 110 surrounding a pipe is shown in FIGS. 8 and 9 . In this embodiment substantially all of the parts may be made of metal but are interchangeable with other materials obvious to those skilled in the art. While this second embodiment functions substantially similarly to the first embodiment discussed above, the second embodiment also includes, among other things, a tensioner 200 with spring 210 , that increases the peeler's ability to peel non-uniform pipe surfaces, e.g., where the pipe does not have a perfectly circular circumference.
[0059] Referring to FIG. 6A , the second embodiment pipe peeler 110 includes a peeler body 120 which is generally cuboid-shaped; however, other embodiments may take other shapes without adverse effect on the device's functionality.
[0060] In this embodiment four wheels 128 are attached to peeler body 120 by attaching wheel bolts 130 to recesses 134 which are threaded (not shown) to receive wheel bolts 130 . Wheels 128 are sandwiched between wheel washers 132 and wheel bolts 130 . The wheels 128 may, for example, include internal ball bearings (not shown) that allow the outer rims of the wheels 128 to rotate while the remainder of each of the wheels 128 are in fixed positions relative to the peeler body 120 .
[0061] Grip 140 is affixed to peeler body 120 by screwing in grip bolts 142 to recesses 144 which are threaded (not shown) to receive grip bolts 142 , thereby securing grip body 150 flush with peeler body 120 . Grip knob 146 includes threaded end 148 that affixes to threaded (not shown) recess 152 in grip body 150 . Of course, a grip body and grip knob may be affixed to the peeler body by other means, for example welding, or manufacturing the peeler and grip as one piece.
[0062] As shown in FIG. 6A , peeler front face 122 includes a front recess 124 . Hook 160 and side washers 166 are secured to peeler body 120 with holding pin 162 that passes through peeler body aperture 164 , hook 160 , and side washers 166 . Distal beveled pin end 168 lodges into matching-size recess (not shown) opposite aperture 164 . Proximal beveled pin end 172 fits into set screw 170 , which is screwed into threaded (not shown) outer portion of aperture 164 , thereby securing holding pin 162 . Note that hook 160 may pivot on holding pin 162 . Release aperture 174 is a smaller diameter than the holding pin 162 and is used as an access hole to push out the holding pin 162 if needed.
[0063] Peeler back face 180 (see, e.g., FIG. 9 ) includes a back recess 182 . Holding pins 184 extend into recess 182 through respective apertures 286 and are held in place in apertures 286 by set screws 188 threaded into threaded (not shown) apertures 190 located on peeler back face 180 . Holding pins 184 fit into pivot block recesses 192 .
[0064] FIG. 7 shows a tensioner 200 cross-section. Tensioner 200 includes an inner shaft 202 with male threads that fit to the female threads of an outer shaft 204 . Outer shaft 204 also includes male threads 206 that fit to the female threads of knob 208 . Disc 212 is between knob 208 and upper end 214 of spring 210 . Lower end 216 of spring may rest against pivot block 218 , and inner shaft 202 goes through pivot block aperture 226 .
[0065] A pin 221 included near first end 222 of chain 220 is affixed to inner shaft 202 through inner shaft aperture 224 .
[0066] Blade body 230 is affixed to peeler body 120 with two blade body bolts 232 screwed into threaded apertures 234 on peeler top face 118 (see FIG. 8 ). Alternatively, blade body 230 may be affixed to peeler body 120 with welding or other means obvious to those skilled in the art.
[0067] Blade shaft 236 goes through blade body 230 through cylindrical aperture 238 . Blade shaft 236 is affixed to blade stop 240 with barrel nut 242 that screws onto corresponding male threads (not shown) on blade shaft 236 .
[0068] Spring 245 on blade shaft 236 is located between blade stop 240 and cylinder 244 . Cylinder 244 includes aperture 246 through which a stabilizing pin 248 is affixed. Bolt 252 affixes blade 254 and blade stop 256 to cylinder 244 .
[0069] Stabilizing pin 248 may move along the major axis of elliptical opening 250 , allowing blade 254 to be in a raised or lowered position. However, stabilizing pin 248 may not move on the minor axis of elliptical opening 250 , and therefore blade shaft 236 and blade 254 may not rotate.
[0070] Second end 262 of chain 220 is affixed to block 263 and magnet 264 with chain pin 260 .
[0071] FIGS. 8 and 9 display this second embodiment with the chain 220 wrapped around a pipe 295 . A first location 221 (e.g., near first end 222 ) on chain 220 is coupled to peeler body 120 near peeler back face 180 via tensioner 200 . Chain 220 is wrapped snugly around pipe 295 , and second location 290 on chain 220 is coupled to peeler body 120 near peeler front face 122 via hook 160 .
[0072] Knob 208 is turned clockwise, thereby threading outer shaft 204 with inner shaft 202 and initially pulling outer shaft 204 (and thus knob 208 and disc 212 ) toward chain first location 260 . However, turning the knob 208 clockwise eventually presses disc 212 against spring 210 , such that spring 210 is compressed between disc 212 and pivot block 218 , which act as stoppers for spring 210 . Thus, further threading of outer shaft 204 with inner shaft 202 will cause inner shaft 202 to pull upwards toward knob 208 thus tightening chain 220 around pipe 295 . (Of course, tightening chain 220 will also cause additional compression to spring 210 .) Chain 220 should be sufficiently snug around pipe 295 such that the device will not slide off the pipe even when the device is not being held by a user, but for optimal use 220 should not be tightened to the point where spring 210 is completely compressed.
[0073] If the length of chain 220 is much larger that pipe 295 circumference and the part of chain 220 not being used extends far beyond point at which hook 160 couples to chain second location 290 , the magnet 264 will attach excess loose chain to the chain surrounding the pipe.
[0074] Once chain 220 is fully tightened around pipe 295 , blade stop 240 may be turned such that projection 241 rests in blade body notch 243 thereby allowing blade 254 to extend downward and contact pipe.
[0075] Back recess 182 is offset from front recess 124 , resulting in second chain location 290 at hook 160 being offset from first chain location 221 / 222 . As a result, as seen in FIGS. 8 and 9 , the chain between first chain location 221 / 222 and second chain location 290 forms a helix shape when this portion of the chain is made into an arc, e.g., when it is wrapped around a pipe. (The amount of offset helps determine the helical angle of the chain 220 secured around a pipe 295 .)
[0076] The embodiment shown in FIGS. 6A-9 is optimal for use where the pipe to be peeled is not perfectly circular, for example, is oval, or is deformed, or changes diameter along its length. Where more “give” is required on chain 220 because a portion of the peeling path is not perfectly circular, spring 210 may compress, thereby allowing chain 220 at first chain location 221 / 222 to move away from peeler back face 180 . Likewise, where the peeling path may ordinarily result in slack on the chain 220 , spring 210 may expand, thus pulling first chain location 221 / 222 toward peeler back face 180 .
[0077] Of course, where the pipe being shaved does not have a uniform circular circumference or constant diameter, the chain likewise may not define a perfect circular helix, even though the tightened chain between first and second locations 260 , 190 will still be substantially helix-shaped. For example, an elliptical pipe may result in the chain defining an elliptical helix, a cone-shape pipe may result in the chain defining a conic helix, a pipe with a bulge may still result in the chain being substantially helical, and so on.
[0078] Various changes, alternatives, and modifications will become apparent to a person of ordinary skill in the art after a reading of the foregoing specification. It is intended that all such changes, alternatives, and modifications as fall within the scope of the appended claims be considered part of the present invention.
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A pipe peeler for removing a uniform layer of material from the outer surface of a polyethylene pipe is provided. The device comprises a body, a blade, a chain coupled near a first face of the body, a means for coupling the other end of the chain to the body near a second face of the body, a means for tightening the chain around a pipe, and a grip for rotating the device around the pipe in order to peel the pipe. The chain may define a helix shape when wrapped around the pipe, creating a spiral track on the pipe that the blade will follow when the device is pushed around the pipe, thereby creating a uniform spiral peel.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-016008, filed on Jan. 29, 2015, the entire contents of which are incorporated herein by reference.
FIELD
The technique disclosed herein relates to a voltage dropping circuit and an integrated circuit.
BACKGROUND
In recent years, a reduction in power consumption of electronic equipment has been desired and the voltage for operating a transistor mounted in an integrated circuit is controlled precisely for each kind of circuit. An integrated circuit has a circuit portion that operates on a base voltage that is supplied from the outside and a circuit portion that operates on a voltage other than the base voltage. The voltage other than the base voltage is generated from the base voltage by using a charge pump circuit or the like, or from the base voltage or a power source voltage that is generated separately by using a low drop out circuit. The power source circuit of the integrated circuit such as this is called an adaptive supply voltage (ASV) system.
Further, in order to reduce the power consumption of an integrated circuit, it is effective to reduce the leak current of a transistor that is mounted in the integrated circuit. As one of method for reducing the leak current of a transistor, an adapting body bias (ABB) system that controls the back gate potential of a transistor is known. The back gate voltage that controls the back gate potential of a transistor is generated by, for example, a low drop out circuit because the current-carrying capacity is small.
In the case where a low drop out circuit that implements the ABB system is provided in an integrated circuit adopting the above-described ASV system, the back gate voltage that is higher than the base voltage is generated from the base voltage whose power source supply capacity is high while the back gate voltage is equal to or less than the base voltage. Specifically, a capacitive element that holds the back gate voltage is charged up to the back gate voltage by the low drop out circuit after being changed up to the base voltage by the base power source. In the low drop out circuit, for example, a transistor is connected between the terminal to which the high-voltage power source voltage is supplied and the terminal from which the back gate voltage is output, and the turning-on/off of the transistor is controlled in accordance with the results of comparison between the back gate voltage and a reference potential.
As described previously, in the power source sequence in the ASV system, the high-voltage power source voltage is generated by the charge pump or the like, and therefore, the supply of the high-voltage power source voltage to each unit within the integrated circuit is delayed from the supply of the base voltage. Consequently, the supply of the high-voltage power source voltage to the low drop out circuit is delayed from the supply of the base voltage. Due to this, in the low drop out circuit, the base voltage is applied to the terminal from which the back gate voltage is output before the high-voltage power source voltage is supplied, and therefore, a current flows backward.
In order to prevent such a backflow of a current in the low drop out circuit, a transistor is diode-connected between the transistor of the low drop out circuit and the supply terminal of the high-voltage power source voltage.
RELATED DOCUMENTS
[Patent Document 1] Japanese Laid Open Patent Publication No. 2004-260052
[Patent Document 2] Japanese Laid Open Patent Publication No. S62-109114
[Patent Document 3] Japanese Laid Open Patent Publication NO. 2013-025695
SUMMARY
According to a first aspect of embodiments, a voltage dropping circuit configured to generate a second power source voltage by dropping a first power source voltage that is supplied to a first node, and to output the second power source voltage to a second node, includes: an output stage transistor, the first power source voltage being configured to be supplied to a first terminal of the output stage transistor, a second terminal of the output stage transistor being connected to the second node, the output stage transistor being configured to turn on or off in accordance with a magnitude relationship between the second power source voltage and a reference voltage; and a back gate variable diode circuit including a diode-connected transistor that is connected between the first node and the first terminal and configured to turn on or off in accordance with a magnitude relationship between the first power source voltage and the second power source voltage, wherein the first power source voltage is applied to the back gate of the diode-connected transistor when the first power source voltage is higher than the second power source voltage, and the second power source voltage is applied to the back gate of the diode-connected transistor when the second power source voltage is higher than the first power source voltage.
According to a second aspect of embodiments, an integrated circuit includes: a first power source circuit configured to generate a first power source voltage from a base voltage that is supplied from the outside; a voltage dropping circuit configured to generate a second power source voltage by dropping the first power source voltage and to output the second power source voltage to a second node; and a logic circuit configured to operate based on the second power source voltage, wherein the second power source voltage is generated from the base voltage when the second power source voltage is lower than the base voltage, and is generated by the voltage dropping circuit after the second power source voltage reaches the base voltage, and the voltage dropping circuit includes: a first node to which the first power source voltage is supplied; an output stage transistor, the first power source voltage being supplied to a first terminal of the output stage transistor, a second terminal of the output stage transistor being connected to the second node, the output stage transistor being configured to turn on or off in accordance with a magnitude relationship between the second power source voltage and a reference voltage; and a back gate variable diode circuit including a diode-connected transistor that is connected between the first node and the first terminal and configured to turn on or off in accordance with a magnitude relationship between the first power source voltage and the second power source voltage, wherein the first power source voltage is applied to the back gate of the diode-connected transistor when the first power source voltage is higher than the second power source voltage, and the second power source voltage is applied to the back, gate of the diode-connected transistor when the second power source voltage is higher than the first power source voltage.
The object and advantages of the embodiments will be realized and attained by means of the elements and combination particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a configuration example of a circuit and a power source system within an integrated circuit;
FIG. 2A illustrates a circuit configuration example Of the low drop out (LDO) circuit;
FIG. 2B illustrates a change in the Pch back gate voltage (VNW) due to the power source sequence when starting the power source in the circuit in FIG. 2A ;
FIG. 2C illustrates a sectional structure of an output stage transistor of the LDO;
FIG. 3A illustrates a first circuit example of the low drop out circuit (LDO) that prevents the backflow of a current;
FIG. 3B illustrates a second circuit example of the low drop out circuit (LDO) that prevents the backflow of a current;
FIG. 3C illustrates a sectional structure of a backflow preventing transistor that is added to the second circuit example;
FIG. 4A illustrates a low drop out circuit (LDO) of a first embodiment;
FIG. 4B illustrates an equivalent circuit of the LDO of the first embodiment when VNW>VDE;
FIG. 4C illustrates an equivalent circuit of the LDO of the first embodiment when VNW<VDE;
FIG. 4D illustrates a sectional structure of a transistor that forms a back gate variable diode circuit;
FIG. 5A illustrates a low drop out circuit (LDO) of a second embodiment;
FIG. 5B illustrates an equivalent circuit of the LDO of the second embodiment when VNW>VDE;
FIG. 5C illustrates an equivalent circuit of the LDO of the second embodiment when VNW<VDE;
FIG. 6A illustrates a low-drop DC/DC converter of a third embodiment;
FIG. 6B illustrates an equivalent circuit of the low-drop DC/DC converter of the third embodiment when Vout>VDE;
FIG. 6C illustrates an equivalent circuit of the low-drop DC/DC converter of the third embodiment when Vout<VDE.
DESCRIPTION OF EMBODIMENTS
Before explaining a low drop out circuit and an integrated circuit that makes use of the low drop out circuit of an embodiment, a general integrated circuit adopting the ABB and ASV systems and a low drop out circuit are explained.
FIG. 1 illustrates a configuration example of a circuit and a power source system within an integrated circuit.
An integrated circuit 10 has a P-type substrate (Psub) 11 . On the P-type substrate 11 , an I/O circuit 12 , a PLL circuit 13 , an AD/DA conversion circuit 14 , a USB interface circuit 15 , a DDR circuit 16 , an ABB+ASV circuit unit 20 , and a well 30 that forms a logic circuit are formed.
The I/O circuit 12 inputs and outputs data and signals from and to the outside. The PLL circuit 13 generates an operation clock. The AD/DA conversion circuit 14 converts an analog signal into digital data and converts digital data into an analog signal. The USB interface circuit IS interfaces with a USB memory. The DDR (Double Data Rate) circuit 16 inputs and outputs data at high speed to and from an external DRAM board.
The ABB+ASV circuit unit 20 is a power source circuit of the integrated circuit 10 and protects the power source and implements the ABB system and the ASV system. The ABB+ASV circuit unit 20 has a charge pump 21 , a low drop out (LDO) 22 , a thermometer 23 , a process monitor 24 , and an electrically programmable fuse element (E-Fuse) 25 . The LDO circuit is an example of voltage dropping circuits.
In the well 30 , a first logic circuit (Logic1) 31 , a second logic circuit (Logic2) 32 , and an SRAM 33 are formed. The supply of a base power source voltage to the second logic circuit is controlled by the ASV system by using a power switch 17 provided outside the well 30 .
The configuration illustrated in FIG. 1 is an example and is designed appropriately in accordance with specifications.
The integrated circuit having the configuration such as described above has a power source wire through which a power source voltage necessary for the operation of each circuit portion is supplied. In the configuration illustrated in FIG. 1 , the integrated circuit has a base power source (VDD) wire 40 , a ground (VSS) wire 41 , a high-voltage power source (VDE) wire 42 , a Pch back gate voltage (VNW) wire 43 , and an Nch back gate voltage (VPW) wire 44 . To the VDD wire 40 and the VSS wire 41 , the base power source (VDD) is supplied from an external power source 1 . The external power source 1 is, for example, a IV power source and the VSS wire 41 becomes the GND (0 V) and the VDD wire 40 becomes 1 V. The high-voltage power source (VDE) is, for example, a 3.3V power source and is used for inputting/outputting with already-existing external equipment. The VDE is generated from the VDD power source by the CP 21 and for stabilization of the power source, a capacitive element 45 and a Schottky barrier diode (SBD) 46 are connected in parallel between the VDE wire 43 and the VSS wire 41 . There is a case where the capacitive element 45 and the SBD 46 are provided within the integrated circuit 10 , but the size is large, and therefore, it is common for them to be attached externally to the integrated circuit 10 as illustrated in FIG. 1 . The VNW is a voltage that controls the back gate potential of the Pch transistor by the ABB system and is generated by the LDO 22 from the VDE power source at a voltage between the VDE power source voltage and the VDD power source voltage. The VPW is a voltage that controls the back gate potential of the Nch transistor by the ABB system and is a negative voltage, and is generated from the VDD power source by the CP 21 . In the case of the VPW also, for stabilization of the power source, between the VPW wire 44 and the VSS wire 41 , an external capacitive element 47 and an SBD 48 are connected in parallel.
The power source wire is formed on the P-type substrate 11 , but in FIG. 1 , the power source wire is illustrated separate from the P-type substrate 11 for making the power source wire easy-to-see.
The circuit configuration and the power source configuration of the integrated circuit illustrated in FIG. 1 are widely known, and therefore, more explanation is omitted.
FIG. 2A illustrates a circuit configuration example of the low drop out (LDO) circuit. FIG. 2B illustrates a change in the Pch back gate voltage (VNW) due to the power source sequence when starting the power source in the circuit in FIG. 2A . FIG. 2C illustrates a sectional structure of an output stage transistor of the LDO. The LDO circuit is an example of voltage dropping circuits.
The LDO 22 has an output stage transistor PTr 1 , an amplifier (AMP) that functions as a comparison circuit, a voltage-dividing circuit of the VDD, a voltage-dividing circuit of the VNW, a charging circuit between the VNW and the VDD. In FIG. 2A , as an example of a logic circuit to which the VDD, VSS, VNW, and VPW are supplied, an inverter circuit is also illustrated.
The output stage transistor PTr 1 is connected between the VDE wire 42 and the VNW wire 43 and the back gate is connected to the VDE wire 42 . Here, the controlled terminal (source) that is connected to the VDE wire 42 of the PTr 1 is referred to as a first terminal and the controlled terminal (drain) that is connected to the VNW wire 42 of the PTr 1 is referred to as a second terminal. Further, there is a case where the VDE wire 42 that is connected to the PTr 1 is referred to as a first node and the VNW wire 43 that is connected to the PTr 1 as a second node. Furthermore, there is a case where the VDE (high-voltage power source, voltage) is referred to as a first power source voltage, the VNW (Pch back gate voltage) as a second power source voltage, and the GND (ground) as a third power source voltage.
The voltage-dividing circuit of the VDD has two resistors R 11 and R 12 connected in series between the VDD wire 40 and the VSS wire 41 and generates a reference voltage by dividing the VDD in a ratio between the resistances of R 11 and R 12 . The voltage-dividing circuit of the VNW has two resistors R 21 and R 22 connected in series between the VNW wire 43 and the VSS wire 41 and generates the divided voltage VNW by dividing the VNW in a ratio between the resistances of R 21 and R 22 . The AMP compares the reference voltage with the divided voltage VNW and increases the output voltage in the case where the divided voltage VNW is higher than the reference voltage, and reduces the output voltage in the case where the divided voltage VNW is lower than the reference voltage. Due to this, the amount of the current flowing through the PTr 1 is reduced in the case where the VNW is higher than a predetermined voltage and the amount of the current flowing through the PTr 1 increases in the case where the VNW is lower than the predetermined, voltage, and thereby, the VNW is controlled to be a predetermined voltage.
In the case where the VNW is higher than the VDD and lower than the VDE, if all the charges for charging the capacitive element 45 of the VNW are generated by dropping the VDE when starting the power source, the burden of the CP 21 is too heavy, and therefore, it is necessary to increase the drive force of the CP 21 in order to shorten the time taken for the power source to start. Consequently, when starting the power source, the capacitive element 45 is charged through the VDD power source wire 40 until the VNW reaches the VDD and after the VNW reaches the VDD, the VNW is increased to a predetermined voltage by the LDO 22 . Because of this, as illustrated in FIG. 2A , there are provided a diode D 1 and a switch SW connected in parallel between the VDD power source wire 40 and the VNW power source wire 43 . The diode D 1 is connected so that the forward direction is from the VDD toward the VNW. The switch SW is controlled by the VDD and turns on when the VDD reaches about 1 V and turns off when the VNW becomes higher than the VDD.
To the back gate of the PMOS that is formed in the first logic circuit 31 and the second logic circuit 32 , the VNW is applied and to the back gate of the NMOS, the VPW is applied, when the values of the VNW and VPW are changed, the power consumption of the PMOS and the NMOS changes.
If the supply of power source from the external power source 1 is started to the integrated circuit 10 at the time of startup, the VDD begins to increase as illustrated in FIG. 2B . When, the VDD reaches about 0.3 V, a current flows through the Schottky barrier diode (SBD) D 1 , and therefore, the VNW increases along the broken line indicated by X with the state where the voltage is lower than the VDD by about 0.3 V being kept. When the VDD reaches about 1 V, the SW turns on and the VNW reaches a voltage almost the same as the VDD in a brief time as represented by the broken line indicated by Y. The generation of the VDE by the CP 21 delays from the startup by a certain period of time, and therefore, the VDE remains 0 V.
As illustrated in FIG. 2C , the PTr 1 is formed in an N well (N-well) 51 formed on the P-sub 11 . The PTr 1 has a drain electrode 52 and a source electrode 54 in the P+ region on the H well 51 , a gate electrode 53 formed right above the N well 51 between the drain electrode 52 and the source electrode 54 , and a back gate electrode 55 in the n+ region of the N well 51 . The source electrode 54 and the back gate electrode 55 are connected to the VDE wire 42 and the drain electrode 52 is connected to the VNW wire 43 . The P-sub 11 is connected to the VSS wire 41 via a region 56 and the voltage is the GND (0 V).
As described above, at the time of starting the power source, in the state where the VDE is 0 V, the VNW becomes the VDD (1 V). When such a state is brought about, as illustrated in FIG. 2C , a diode whose forward direction is from the drain electrode 52 toward the back gate electrode 55 of the PTr 1 is formed and a current flows backward from the VNW wire 43 to the VDE wire 42 .
FIG. 3A illustrates a first circuit example of the low drop out circuit (LDO) that prevents the backflow of a current. FIG. 3B illustrates a second circuit example of the low drop out circuit (LDO) that prevents the backflow of a current. FIG. 3C illustrates a sectional structure of a backflow preventing transistor that is added to the second circuit example.
The LDO in the first circuit, example illustrated in FIG. 3A is a circuit in which the P-channel PTr 1 has been replaced with the N-channel PTr 1 and the backflow from the VNW wire 43 to the VDE wire 42 is prevented by connecting the back gate to the VSS wire (GND). However, the LDO in FIG. 3A back-biases (about 1 V) the back gate of the output stage transistor, and therefore, the drive force of the output, stage transistor is reduced. Further, by changing the P channel to the N channel, the BSD (Electro-Static Discharge) resistance between the VDE wire 42 and the VNW wire 43 is reduced.
The LDO in the second circuit example illustrated in FIG. 3B is a circuit, in which a P-channel PTr 2 has been further connected between the output stage transistor PTr 1 and the VDE wire 42 . The PTr 2 is diode-connected and the back gate is connected to the drain (source of the PTr 1 ). The PTr 2 connected like this forms a diode whose forward direction is from the VDE wire 42 toward the source or the PTr 1 . Due to this, the backflow from the VNW wire 43 to the VDE wire 42 via the PTr 1 is prevented. The sectional structure of the PTr 2 illustrated in FIG. 3C is the same as that explained in FIG. 2C , and therefore, explanation is omitted.
However, in the LDO in FIG. 3B , the back gate of the PTr 2 is forward-biased during the normal operation and as illustrated in FIG. 3C , there is a possibility that an overcurrent will flow through a diode that is formed so that the forward direction is from a source electrode 62 toward a back gate electrode 65 of the PTr 2 .
In the embodiment that is explained below, a low drop out circuit (LDO) is disclosed, which prevents the backflow of a current, and at the same time, through which an overcurrent does not flow during the normal operation.
FIG. 4A illustrates a low drop out circuit (LDO) of a first embodiment. FIG. 4B illustrates an equivalent circuit of the LDO of the first embodiment when VNW>VDE. FIG. 4C illustrates an equivalent circuit of the LDO of the first embodiment, when VNW<VDE. FIG. 4D illustrates a sectional structure of a transistor that forms a back gate variable diode circuit.
It is possible to use the low drop out circuit (LDO) of the first embodiment as the LDO 22 of the integrated circuit in FIG. 1 .
As illustrated in FIG. 4A , the low drop out circuit (LDO) of the first embodiment has a back gate variable diode circuit that is connected between the output stage transistor PTr 1 and the VDE wire 42 . In other words, the LDO of the first embodiment differs from the LDO illustrated in FIG. 3B in that the back gate variable diode circuit is provided in place of the PTr 2 .
The LDO of the first embodiment has the output stage transistor PTr 1 , the AMP, the voltage-dividing circuit of the VDD including R 11 and R 12 , the voltage-dividing circuit of the VNW including R 21 and R 22 , the charging circuit between VNW and VDD including D 1 and SW, and the back gate variable diode circuit. The portions other than the back gate variable diode circuit are the same as the elements explained in FIG. 2A to FIG. 3C , and therefore, explanation is omitted.
The back gate variable diode circuit has Pch transistors PTr 21 , PTr 22 , and PTr 23 . The PTr 21 is diode-connected between the output stage transistor PTr 1 and the VDE wire 42 . In other words, the gate of the PTr 21 is connected to the drain of the PTr 21 (source of PTr 1 ). The PTr 22 and PTr 23 are connected in series between the PTr 1 and the VDE wire 42 , and in parallel to the PTr 21 . The gate of the PTr 22 is connected to the VDE wire 42 , the gate of the PTr 23 is connected to the source of the PTr 1 , and the back gates of the PTr 22 and PTr 23 are connected to the connection node of the PTr 22 and PTr 23 . Further, the back gate of the PTr 21 is connected to the connection node of the PTr 22 and PTr 23 . Here, the potential of the source of the PTr 1 is denoted by Va.
When VNW>VDE, the LDO in FIG. 4A becomes the equivalent circuit illustrated in FIG. 4B . In other words, the back gate variable diode circuit is represented by the PTr 21 that is diode-connected and whose back gate is connected to the source of the PTr 1 . When VNW>VDE, Va>VDE (VNW>Va>VDE) holds, and the PTr 22 turns on and the PTr 23 turns off. Because of this, the back gate of the PTr 21 is connected to the source of the PTr 1 and a state where Va is applied is brought about. As explained in FIG. 3B , the PTr 21 in FIG. 4B functions as a diode whose forward direction is from the VDE wire 42 toward the PTr 1 , and therefore, the backflow from the VNW wire 43 to the VDE wire 42 , which occurs when VNW>VDE, is prevented.
When VNW<VDE (during normal operation), the LDO in FIG. 4A becomes the equivalent circuit illustrated in FIG. 4C . In other words, the back gate variable diode circuit is represented by the PTr 21 that is diode-connected and whose back gate is connected to the VDE wire 42 . When VNW<VDE, Va<VDE (VNW<Va<VDE) holds, and the PTr 22 turns off and the PTr 23 turns on. Because of this, the back gate of the PTr 21 is connected to the VDE wire 42 and a state where the VDE is applied is brought about. The PTr 21 in this state is in the conduction state and allows a current from the VDE wire 42 to the PTr 1 to pass.
The PTr 21 in the state in FIG. 4C is in the state where the VDE is applied to the source electrode 62 , Va is applied to a gate electrode and a drain electrode 64 , and the VDE is applied to the back gate electrode 65 as illustrated in FIG. 4D . Consequently, no forward bias is applied to the back gate and a diode whose forward direction is from the source electrode 62 toward the back gate electrode 65 is not formed, and therefore, it is unlikely that an overcurrent flows.
As explained above, the low drop out circuit (LDO) of the first embodiment prevents the occurrence of an overcurrent when VNW<VDE, as well as preventing a backflow when VNW>VDE.
FIG. 5A illustrates a low drop out circuit (LDO) of a second embodiment. FIG. 5B illustrates an equivalent circuit of the LDO of the second embodiment when VNW>VDE. FIG. 5C illustrates an equivalent circuit of the LDO of the second embodiment when VNW<VDE.
It is also possible to use the low drop out circuit (LDO) of the second embodiment as the LDO 22 of the integrated circuit in FIG. 1 .
The LDO of the second embodiment differs from that of the first embodiment in that the gate of the PTr 21 of the back gate variable diode circuit is not connected to the source of the PTr 1 but is connected to the drain of the PTr 1 .
As in the first embodiment, the LDO of the second embodiment becomes the equivalent circuit illustrated in FIG. 5B when VNW>VDE and prevents the backflow from the VNW wire 43 to the VDE wire 42 . Further, the LDO of the second embodiment becomes the equivalent circuit illustrated in FIG. 5C when VNW<VDE (during normal operation) and prevents the forward bias of the back gate of the PTr 21 .
In the first embodiment, when VNW<VDE (during normal operation), a gate-source voltage Vgs of the PTr 1 is reduced due to a drain-source voltage Vds of the PTr 21 , and therefore, the drive force of the LDO is reduced. In contrast to this, in the second embodiment, the gate potential of the PTr 21 is connected to the VNW wire 43 , which is lower than Va, and therefore, the gate-source voltage Vgs of the PTr 21 increases and it is possible to reduce the drain-source voltage Vds of the PTr 21 . Hereinafter, the principle that the Vds of the PTr 21 is reduced is explained.
A drain current Id in the saturation region of a MGS transistor is expressed as Id=1/2×W/L×μ×Co×(Vgs−Vth) 2 ×(1+λVds). Here, W is the channel width, L is the channel length, μ is the mobility. Co is a gate oxide film, Vgs is the gate-source voltage, Vth is a threshold value, λ is the channel length modulation coefficient, and Vds is the drain-source voltage.
In the LDO of the first embodiment, it is assumed that the drain current of the PTr 21 is denoted as Ids 1 , the gate-source voltage as Vgs 1 , and the drain-source voltage as Vds 1 . Similarly, in the LDO of the second embodiment, it is assumed that the drain current of the PTr 21 is denoted as Ids 2 , the gate-source voltage as Vgs 2 , and the drain-source voltage as Vds 2 . Then, if it is supposed that W, L, μ, Co, Vth, and λ are the same in the first and second embodiments, and Ids 1 =Ids 2 , then Vgs 1 <Vgs 2 , and therefore, Vds 1 >Vds 2 holds.
Consequently, the potential Va of the source of the PTr 1 increases, the Vgs of the PTr 1 increases, and the drive force of the LDO increases.
As explained above, the low drop out circuit (LDO) of the second embodiment prevents the occurrence of an overcurrent when VNW<VDE, as well as preventing the backflow when VNW>VDE, and the drive force of the output stage transistor PTr 1 when VNW<VDE (during normal operation) is high compared to that of the first embodiment.
It is also possible to apply the back gate variable diode circuits explained in the first and second embodiments to a low-drop DC/DC converter.
FIG. 6A illustrates a low-drop DC/DC converter of a third embodiment. FIG. 6B illustrates an equivalent circuit of the low-drop DC/DC converter of the third embodiment when Vout>VDE. FIG. 6C illustrates an equivalent circuit of the low-drop DC/DC converter of the third embodiment when Vout<VDE. The low-drop DC/DC converter is an example of voltage dropping circuits.
The low-drop DC/DC converter of the third embodiment generates an output voltage Vout by dropping the high voltage VDE. The low-drop DC/DC converter has the output stage transistor PTr 1 , a back gate variable diode circuit, an inductor (coil) L, a capacitive element G, a diode D 10 , a voltage-dividing circuit, a reference power source Vref, an AMP 10 , and a PWM control circuit 71 .
The source (first terminal) of the PTr 1 is connected to the VDE wire 42 via the back gate variable diode circuit. The back gate variable diode circuit is the same as that of the first embodiment. The gate of the PTr 1 is connected to the output of the PWM control circuit 71 . The drain (second terminal) of the PTr 1 is connected to the VSS wire (GND) via the diode D 10 . The diode 10 is connected so that the direction from the GND toward the second terminal of the PTr 1 is the forward direction. The inductor L is connected to the second terminal of the PTr 1 and the second node (VNW wire) 43 . The capacitive element C is connected between the second node and the GND. The voltage-dividing circuit has two resistors R 31 and R 32 connected in series between the second node and the GND. The resistors R 31 and R 32 output the Vout divided voltage, which is obtained by dividing the output voltage Vout that appears at the second node in a ratio between the resistances of R 31 and R 32 , from the connection node of R 31 and R 32 . The AMP compares the Vout divided voltage with the reference voltage Vref, generates a PWM signal in accordance with the results of the comparison, and applies the PWM signal to the gate of the PTr 1 . Specifically, in the case where the Vout divided voltage is lower than the reference voltage Vref, the ratio (duty) of the low level of the PWM signal is increased and in the case where the Vout divided voltage is higher than the reference voltage Vref, the ratio (duty) of the low level of the PWM signal is reduced. Due to this, the output voltage Vout is controlled to be a predetermined voltage.
Hereinafter, the operation of the back gate variable diode circuit in the third embodiment is explained.
When Vout>VDE, the back gate variable diode circuit becomes the equivalent circuit illustrated in FIG. 6B . In other words, the back gate variable diode circuit is represented by the PTr 21 that is diode-connected and whose back gate is connected to the source of the PTr 1 . When Vout>VDE, Va>VDE (and Va<Vout) holds, and the PTr 22 turns on because the gate potential becomes the VDE and the source potential becomes Va. On the other hand, the PTr 23 turns off because the gate potential becomes Va and the source potential becomes the VDE. Because of this, the back gate potential becomes Va (Vout) and the PTr 21 turns off, and therefore, the backflow from the second node (VNW 43 ) to the VDE wire is prevented.
When Vout<VDE (during normal operation), the back gate variable diode circuit becomes the equivalent circuit illustrated in FIG. 6C . In other words, the back gate variable diode circuit is represented by the PTr 21 that is diode-connected and whose back gate is connected to the VDE wire 42 . When Vout<VDE, Va<VDE (and Va>Vout) holds, and the PTr 23 turns on because the gate potential becomes Va and the source potential becomes the VDE. On the other hand, the PTr 22 turns off because the gate potential becomes the VDE and the source potential becomes the VDE. Because of this, the PTr 21 turns on because the back gate potential becomes the VDE, and at the same time, the forward bias is not applied to the back gate, and therefore, no overcurrent occurs.
All examples and conditional language provided herein are intended for pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a illustrating of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail. It should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
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A voltage dropping circuit generating a second power source voltage to output to a second node by dropping a first power source voltage supplied to a first node, includes: an output transistor having a first terminal to which the first power source voltage is supplied and a second terminal connected to the second node turns on or off according to a difference between the second power source voltage and a reference voltage; and a back gate variable diode circuit including a diode-connected transistor connected between the first node and the first terminal and to configured to turn on or off according to a voltage difference between the first and second power sources, wherein the first power source voltage is applied to the back gate of the diode-connected transistor when it is higher than the second power source voltage, and the second power source voltage is applied in other case.
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This application is a continuation of application Ser. No. 07/731,234, filed Jul. 17, 1991 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a metallic gasket for use in sealing a clearance between the opposed surfaces of a cylinder head and a cylinder block in a multicylinder engine.
2. Description of the Prior Art
In a recent internal combustion engine, the increasing of the level of an output and the reducing of the weight have been demanded. Accordingly, a cylinder head and a cylinder block have been formed to smaller dimensions since the distance between adjacent cylinders, i.e. the distance between adjacent cylinder bores have increasingly been reduced. The distance between adjacent cylinder bores which is measured on the cylinder block is recently around 6 mm. Moreover, in order to further reduce the weight of an engine, the cylinder head and cylinder block tend to be produced out of an aluminum material having a low specific gravity. The low rigidity of an aluminum material and the small distance between adjacent cylinder bores have caused the rigidity of a cylinder head and a cylinder block of a recent internal combustion engine to tend to lower.
In view of such a tendency, a metallic gasket shown in FIG. 10 has been proposed. This metallic gasket has a base member 21 consisting of an elastic metallic material and provided with cylinder bore-aligned holes, i.e. combustion chamber-aligned holes 23 and beads 24 surrounding the combustion chamber-aligned holes 23, and is adapted to seal the clearance between the cylinder head and cylinder block. In the metallic gasket 20, an auxiliary member 22 is laminated on the side of the base member 21 which is on the opposite side the surface thereof from which a bead 24 projects, and the edges of the auxiliary member 22 which are on the sides of the combustion chamber-aligned holes 23 are folded back onto the surface of the base member 21 so as to wrap the edge portion of the base member 21, whereby compensating portions 25 of a predetermined thickness are provided in positions on the side of the combustion chamber-aligned holes 23 and away from the beads 24. The metallic gasket 20 formed as described above prevents a combustion gas pressure and engine heat from causing the clearance between the opposed surfaces of the cylinder block and cylinder head to be widened and narrowed, and decreases the alternating load working on the bead 24, whereby the stress on the bead 24 is reduced. Since the surface pressure is dispersed to the compensating portions, the fatigue of the metallic gasket is prevented. The compensating portions constituting primary seals function as stoppers against the deformation of the bead 24 constituting a secondary seal. Since the portions around the combustion chamber-aligned holes 23 are sealed with both the compensating portions 25 and bead 24, the leakage of a combustion gas is prevented more reliably. The metallic gaskets having the above-described structure include metallic gaskets disclosed in, for example, the specifications and drawings of Japanese Patent Laid-open No. 155376/1987 and U.S. Pat. No. 3,817,540.
In the metallic gasket 20, a compensating portion 25 constituting a grommet consists of a total of three layers including the base member 21 and a folded auxiliary member 22, i.e. a two-layer auxiliary member 22. On the other hand, a bead consists of two layers having a closed hollow space therebetween, and the portion which is between the compensation portion 25 and bead 24 consists of two layers composed of the base member 21 and auxiliary member 22 contacting each other. Accordingly, the portion of an auxiliary member 22 which is positioned on the upper side of a folded portion thereof, and a folded portion, i.e. a compensating portion 25 are exposed directly to the variation of load and vibration occurring between the cylinder head and cylinder block. Therefore, when an auxiliary member 22 formed to a small thickness is used for a long period of time, a folded portion becomes ready to be cracked. Conversely, when an auxiliary member 22 formed to a large thickness is used, a tightening load occurring when the cylinder head is tightened with respect to the cylinder block is apt to be comparatively concentrated on a three-layer compensating portion 25, so that uniform surface pressure distribution cannot be secured around the cylinder bore-aligned holes. Consequently, an excellent sealed condition cannot be maintained for a long period of time.
The conventional metallic gaskets also include a metallic gasket shown in FIG. 11. This metallic gasket 30 includes in the upper part thereof a metallic upper member 31 provided with beads 34 surrounding cylinder bore-aligned holes 33, and in the lower part thereof a lower member 32 laminated on the lower surface of the upper member 31 and bent at its edge portions on the side of the cylinder bore-aligned holes 33 toward the upper member 31 to form the cylinder bore-aligned holes 33 with shims 36 of a high rigidity provided in the spaces surrounded by the inner edge portions of the upper member 31 and the bent portions of the lower member 32. When such a metallic gasket 30 is pressed by the cylinder head and deformed to a level not lower than a predetermined level, the cylinder head contacts the shims 36. Since the shims 36 have a high rigidity, the metallic gasket 30 is not deformed any more, and it is expected that the beads 34 does not fatigue. This type metallic gaskets include a metallic gasket disclosed in, for example, Japanese Utility Model Laid-open No. 134966/1987.
In the metallic gasket 30, the shims 36 are provided immovably in the spaces surrounded by the inner edge portion of the upper member 31 and the bent portions 35 consisting of the edge portions of the lower member 32 which are on the side of the cylinder bore-aligned holes 33, and turned up toward the upper member 31. Therefore, it is necessary to prepare the shims 36 additionally, and the number of parts for manufacturing the metallic gasket 30 and the cost of manufacturing the same increase. The main portion of the lower member 32 and the portions thereof which are wrapped around the shims 36 contact the cylinder head and cylinder block as in the previously-described prior art metallic gasket. Accordingly, when the lower member 32 is formed to a small thickness, cracks are liable to occur, and, conversely, when the lower member 32 is formed to a large thickness, uniform surface pressure distribution cannot be secured around the cylinder bore-aligned holes 33.
A metallic gasket shown in FIG. 12 has also been proposed. A metallic gasket 40 consists of a base member 41 composed of an elastic metal plate, and provided thereon with a bead 44 surrounding a cylinder bore-aligned hole 43, to seal the same hole 43. An auxiliary member 42 the thickness of which is larger than that of the base member 41 is laminated on the side of the base member 41 which is opposite to the side thereof on which the bead 44 is formed, and the edge portion of the auxiliary member 42 which is on the side of the cylinder bore-aligned hole 43 is folded back on itself to form a compensating portion 45 of a predetermined thickness around the cylinder bore-aligned hole 43 with the inner end of the base member 41 and the end of the compensating portion 45 spaced from each other by a predetermined distance. Accordingly, although the bead 44 in the base member 41 is compressively deformed when the cylinder head is tightened onto the cylinder block, the folded portion 45 is not damaged and broken since the end surface of the inner circumferential portion of the base member 41 is not in contact with the folded portion 45 of the auxiliary member 42. Consequently, it can be expected that the lifetime of the metallic gasket 40 is prolonged. This type of metallic gaskets include a metallic gasket disclosed in, for example, Japanese Patent Laid-open No. 211660/1989.
In the metallic gasket 40, the thickness of the auxiliary member 42 laminated on the base member 41 provided with the bead 44 surrounding the cylinder bore-aligned hole 43 is larger than that of the base member 41. Therefore, when the cylinder head is tightened with respect to the cylinder block, a tightening load is apt to be comparatively concentrated on the compensating portion 45, so that uniform surface pressure distribution cannot be secured around the cylinder bore-aligned hole 43. The reasons reside in that, if the thickness of the bead-carrying member and that of the auxiliary member are set equal, a tightening load is not necessarily be concentrated on the folded compensating portion. It is in any case necessary in this metallic gasket 40 that the thickness of the auxiliary member 42 be set larger than that of the base member 41. Since the thickness of the auxiliary member 42 is large, the processability thereof is low, and cracks are liable to occur in the folded portion, the manufacturing cost becoming high. Moreover, a total thickness of the metallic gasket becomes large. Since the thickness of the auxiliary member 42 is large, it is difficult that the surface pressure distribution on the side of the auxiliary member 42 (cylinder block surface, for example, when the auxiliary plate 42 is disposed on the side of the cylinder block) be set proper, and it is impossible to generate the concentration of surface pressure in a predetermined position. Consequently, the surface pressure disperses more than necessary, and excellent sealed condition cannot after all be maintained.
SUMMARY OF THE INVENTION
An object of the present invention is to solve these problems, and provide a metallic gasket having a base member provided with beads, and an auxiliary member laminated on the bead-carrying base member and provided with a folded portion on the auxiliary member; formed so that, when the bead-carrying base member and auxiliary member are tightened between a cylinder head and a cylinder block, the folded portions contact a flat surface portion of the bead-carrying base member to limit the deformation of the beads and prevent the beads from being completely compressed; and capable of distributing a face-to-face pressure uniformly and improving the sealability while securing the strength of the beads without causing cracks to occur in the beads, and a tightening load to be concentrated on the folded portions of the auxiliary member.
Another object of the present invention is to provide a metallic gasket consisting mainly of a bead-carrying base member formed out of an elastic metallic material and provided with beads along the circumferential portions of parallel-arranged first cylinder bore-aligned holes, an auxiliary member laminated on the bead-projecting side of the bead-carrying base member and spaced in a no-load state at the end portions which are on the side of second cylinder bore-aligned holes from a flat surface portion of the bead-carrying base member, and folded portions formed by folding back the end portions of the auxiliary member which are on the side of the second cylinder bore-aligned holes onto the bead-carrying base member so as not to be put over the beads.
When this metallic gasket is tightened between a cylinder head and a cylinder block, the bead-carrying base member is deformed so that the beads are crushed, due to the elastic effect of the elastic metal material thereof. During this time, the portions of the bead-carrying base member which are between the beads and the end portions on the side of the first cylinder bore-aligned holes are deformed so as to be crushed toward the first cylinder bore holes. The folded portions of the auxiliary member are simply directed in a free state from and toward the bead-carrying base member so as not to be laminated on the beads, and the auxiliary member does not embrace the bead-carrying base member. Namely, the folded portions are permitted to relatively move between the inner ends thereof and the opposed ends of the beads, and do not receive a tensile stress or a displacing force from the bead-carrying base member in an initial stage of a tightening operation. The folded portions function as stoppers for the bead-carrying base member, restrict the deformation of the beads and minimize the occurrence of fatigue of cracks in the beads, protect the beads in the bead-carrying base member and secure the strength of the beads.
Since the edge parts of the folded portions of the auxiliary member which are on the side of the second cylinder bore holes are folded back in the space between the auxiliary member and bead-carrying base member, one of the bead-carrying base member and auxiliary member is in contact with the cylinder head, and the other the cylinder block. Accordingly, the displacement between the cylinder head and cylinder block due to the variation of load and the vibration of parts does not directly work on the folded portion-included auxiliary member alone; it can be absorbed by the portion between the folded portion and base member. Therefore, variation of stress rarely occurs in the folded portion, and cracks and fatigue do not occur in the metallic gasket even when it is used for a long period of time.
This metallic gasket has a simple structure but the parts of the gasket in which the folded portions of the auxiliary member are positioned have three layers. Although the number of bead provided between the first cylinder bore-aligned holes is one, the number of sealed surface in which a face-to-face pressure occurs is three including the two folded portions plus the bead. Accordingly, when the cylinder head and cylinder block are tightened with this metallic gasket set between the opposed surfaces thereof, the bead is compressed forcibly against the auxiliary member to reduce the height of the bead and simultaneously press the folded portions of the auxiliary member against the flat surface portions of the bead-carrying base member which are on the side of the first cylinder bore holes. Even when the bead is pressure-deformed, it is not completely compressed, i.e., the lower portions of the bead the height of which corresponds to the thickness of a folded portion, i.e. the thickness of one layer of the gasket are left uncompressed. This enables the occurrence of fatigue and cracks in the bead to be prevented, the excellent sealing function of the metallic gasket against a high-temperature high-pressure combustion gas to be displayed, and the leakage of a combustion gas to be prevented.
The range in which a folded portion is extended can be set arbitrarily unless the folded portion does not overlap the bead. Accordingly, when the metallic gasket is designed, the distribution of face-to-face pressure on the bead and folded portions can be regulated. Since the thickness of the auxiliary member can be set arbitrarily, this member can display its function as a shim. It also works as a member for fitting the metallic gasket excellently in the clearance between the cylinder head and cylinder block, and improves its function of sealing the space between the opposed surfaces of the cylinder head and cylinder block.
Still another object of the present invention is to provide a metallic gasket having a bead-carrying base member and an auxiliary member each of which is coated at both surfaces thereof or the surface thereof which contacts a cylinder head or a cylinder block with heat resisting and oil resisting rubber or resin so as to avoid the direct metal-to-metal contact between the base and auxiliary members and cylinder head and cylinder block, and capable of improving the corrosion resistance and durability of the gasket, securing the strength thereof and fulfilling the sealing function thereof satisfactorily.
A further object of the present invention is to provide a metallic gasket having a soft member of a uniform thickness inserted between an auxiliary member and folded portions thereof so as to extend over the whole circumferential length thereof, or a stepped soft member inserted between the auxiliary member and folded portions thereof so that a larger-thickness portion thereof is positioned between adjacent cylinder bore holes, or a soft member inserted between only the parts of the auxiliary member and folded portions thereof that are between adjacent cylinder bore-aligned holes.
When a soft member is inserted between the auxiliary member and folded portions thereof in this metallic gasket, the thickness of the portions of the gasket which include the folded portions increases, and the soft member functions as a buffer member to enable a face-to-face pressure suitable to the rigidity of a cylinder head to be secured, the distribution of face-to-face pressure on the metallic gasket to be properly compensated, the face-to-face pressures on the cylinder head- and cylinder block-contacting surfaces of the gasket and that on the beads to be balanced with each other. In order to effect the securing of a face-to-face pressure on the gasket suitable for the rigidity of the cylinder head, the proper compensation of face-to-face pressure distribution, and the balancing of the surface pressures on the cylinder head- and cylinder block-contacting surfaces and that of the beads, a soft member of a uniform thickness is inserted between the auxiliary member and folded portions thereof so as to extend over the whole circumferential length thereof, or a stepped soft member is inserted between the auxiliary member and folded portions thereof so that a larger-thickness portion thereof is positioned between adjacent cylinder bore-aligned holes, or a soft member is inserted in a certain case between only the parts of the auxiliary member and folded portions thereof that are between adjacent cylinder bore-aligned holes.
While the engine is operated, a force, such as a tensile force due to vibration and explosion occurs between the cylinder head and cylinder block. However, since the auxiliary member is laminated on the bead-carrying base member, especially, the lateral vibration does not work on the bead-carrying base member only, so that a damage to the bead-carrying base member due to the friction thereof on the cylinder head or cylinder block is avoided. The vibration or an impact in the vertical direction, i.e. the perpendicular direction of the bead-carrying base member is not directly imparted from the cylinder head or cylinder block to both surfaces of the base member, and the auxiliary member therefore has a kind of buffer action against the bead-carrying base member. Since the folded portions of the auxiliary member do not embrace the bead-carrying base member, parts influenced directly by the variation of load and vibration are not limited to the auxiliary member, and the folded portions of the auxiliary member are not fatigued and cracked. Unlike the main body and folded portions of an auxiliary member of a conventional metallic gasket, the corresponding parts of the auxiliary member in the present invention do not receive large stress and strain, so that inexpensive materials of a high processability can be selectively used.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of an embodiment of the metallic gasket according to the present invention;
FIG. 2 is a sectional view of the embodiment of the metallic gasket taken along the line 44--44 in FIG. 1;
FIG. 3 is a sectional view of the embodiment of the metallic gasket taken along the line 45--45 or 46--46 in FIG. 1;
FIG. 4 is a sectional view of another embodiment of the metallic gasket taken along a line corresponding to the line 44--44 in FIG. 1;
FIG. 5 is a sectional view of the embodiment of FIG. 4 taken along a line corresponding to the line 45--45 or 46--46 in FIG. 1;
FIG. 6 is a sectional view of still another embodiment of the metallic gasket taken along a line corresponding to the line 44--44 in FIG. 1;
FIG. 7 is a sectional view of the embodiment of FIG. 6 taken along a line corresponding to the line 45--45 or 46--46 in FIG. 1;
FIG. 8 is a sectional view of a further embodiment of the metallic gasket taken along a line corresponding to the line 44--44 in FIG. 1;
FIG. 9 is a sectional view of the embodiment of FIG. 8 taken along a line corresponding to the line 45--45 or 46--46 in FIG. 1;
FIG. 10 is a sectional view of an example of a conventional metallic gasket;
FIG. 11 is a sectional view of another example of a conventional metallic gasket; and
FIG. 12 is a sectional view of still another example of a conventional metallic gasket.
FIG. 13 is a sectional view of the metallic gasket in a compressed state.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments of the metallic gasket according to the present invention will now be described with reference to the drawings. FIG. 1 is a plan view of a general embodiment of the metallic gasket according to the present invention.
This metallic gasket 1 is used to seal a clearance between the opposed surfaces of a cylinder head and a cylinder block in a multicylinder engine, such as a four-cylinder engine. This metallic gasket 1 consists mainly of a bead-carrying base member 10 and an auxiliary member 11. The bead-carrying base member 10 is provided with cylinder bore holes 2, the number of which corresponds to that of the cylinder bores in the cylinder block, formed in parallel with one another, and the auxiliary member 11 a plurality of cylinder bore holes 3 correspondingly to the cylinder bore holes 2 and in parallel with one another. The metallic gasket 1 is further provided with a plurality of bolt holes 4, 6 for use in connecting the cylinder block and cylinder head together, and a plurality of holes for passing cooling water therethrough, holes for passing an oil therethrough, oil return holes 5, knock holes 7 and rivet holes 8.
FIG. 2 shows an embodiment of the metallic gasket in section taken along the line 44--44 in FIG. 1, which line extends across a border portion between adjacent cylinder bore holes 2, 3 and connects the centers of these holes 2, 3. FIG. 3 shows the same embodiment of the metallic gasket in section taken along the line 45--45 or 46--46 in FIG. 1, which line passes the center of the extreme end cylinder bore holes 2, 3 and extends across a portion between these cylinder bore-aligned holes 2, 3 and the outermost edge portion of the metallic gasket 1.
This metallic gasket 1 basically consists of a bead-carrying base member 10, and an auxiliary member 11 as shown in FIGS. 2 and 3. The bead-carrying base member 10 consists of a metallic spring plate of about 0.25 mm in thickness, and the material for the spring plate is selected from SUS 301 and SUS 304, or SK1-7, which has a Vickers' hardness HV of 350-500. The auxiliary member 11 consists of a metallic spring plate of about 0.12 mm in thickness, and the material for the spring plate is selected from SUS 304, aluminum-plated steel plate SA1C, regular steel plate SPCC and zinc-plated steel plate SECC, the Vickers' hardness Hv of which is set selectively to not more than 200.
In this metallic gasket 1, the surfaces of the bead-carrying base member 10 and auxiliary member are coated with heat resisting and oil resisting rubber or resin to a thickness of, for example, around 10-50μ. This coating operation may be carried out for both surfaces of the bead-carrying base member and auxiliary member, or for the contact surfaces only of the cylinder head and cylinder block in some cases. If the surfaces of the bead-carrying base member 10 and auxiliary member 11 are coated in such a manner, the metal-to-metal contact of the gasket with the cylinder head and cylinder block is avoided, the corrosion resistance and endurance of the gasket can be improved. It also becomes possible to secure a satisfactory strength of the gasket and sufficiently fulfill its sealing function.
As shown in FIGS. 1 and 2, the bead-carrying base member 10 is provided with a bead 12 around each cylinder bore hole 2, the height of which bead 12 is 0.2-0.3 mm. The portions of two adjacent beads 12 around adjacent cylinder bore holes 2 which meet each other are united into one to form a common bead portion. A range designated by a reference letter a in FIG. 2 of the bead-carrying base member 10 has a flat surface, i.e., forms a flat portion 14, and a range designated by a reference letter b is a curved portion which forms the bead 12 on the base member 10. For example, the length of each of the ranges a, b is 2.0 mm, and a minimum width W of the cylinder bore hole 2 in the metallic gasket 1 is 6.0 mm including the lengths of the ranges a, b.
The auxiliary member 11 is laminated on the side of the bead-carrying base member 10 from which the beads 12 project. The auxiliary member 11 as a whole is formed to substantially the same shape as the bead-carrying base member 10. An auxiliary member body extends substantially flat, and the circumferential edge, which is around each cylinder bore-aligned hole 3, of the auxiliary member is folded back on the side of the bead-carrying base member 10 to form a folded portion 13. The width d of the folded portion 13 is 1.5 mm, and the free end of the folded portion 13 is not superposed on the bead 12 on the base member 10. The auxiliary member 11, in a free state in which it has not yet been tightened with respect to the bead-carrying base member 10, i.e., in a no-load state, contacts the base member 10 along closed curves connected to the apex of the bead 12. Namely, the auxiliary member 11 is laminated on the side of the base member 10 from which the bead 12 projects, and spaced at the end portions thereof which are on the side of the cylinder bore holes 3 from the flat portion 14 of the bead-carrying base member 10. The folded portion 13 of the auxiliary member 11 is formed by folding back the end portion thereof which is on the side of the cylinder bore holes 3 toward the bead-carrying base member 10 in such a manner that the folded portion is not superposed on the bead 12. During the production of a metallic gasket 1, the bead-carrying base member 10 and auxiliary member 11 may be fastened to each other tentatively after they have been made, at several portions of the upper side of each bead 12 so as to be unitized.
The metallic gasket 1 is tightened between the cylinder head and cylinder block but it is not decided strictly beforehand which of the two, i.e. the base member 10 and auxiliary member 11 should be placed on the side of the cylinder head. When bolts are passed through the bolt holes 4, 6 to tighten the metallic gasket 1 between the cylinder head and cylinder block, each bead 12 is compressed forcibly against the auxiliary member 11 to receive a load, so that the height of the bead 12 is reduced. Since the bead 12 is deformed in the direction of the height thereof, the folded portions 13 of the auxiliary member 11 are pressed against the flat portions 14, which are on the side of the cylinder bore holes 2, of the bead-carrying base member 10. This tightened or compressed state is illustrated in FIG. 13.
When the auxiliary member 11 has folded portions 13, the metallic gasket 1 necessarily consists of three layers, and the thickness of the parts of the metallic gasket 1 which is provided with the folded portions 13 is therefore larger than that of the other. Accordingly, the folded portions 13 function as stoppers, and the bead 12 is prevented from being completely compressed, i.e., it is kept as thick as the thickness of a folded portion 13. This can prevent fatigue and cracks from occurring in the bead 12 of the bead-carrying base member 10. The width of the folded portions 13 can be set arbitrarily unless the folded portions 13 are superposed on the bead 12 on the base member 10. Since the width to which the auxiliary member 11 is folded to form these portions 13 has a considerable degree of freedom, the distribution of face-to-face pressure thereof with respect to the bead 12 can be regulated. Since the thickness of the auxiliary member 11 can be set arbitrarily, this member can display its function as a shim and its function of fitting the metallic gasket 1 in the clearance between the cylinder head and cylinder block, and improves its function of sealing the opposed surfaces of the cylinder head and cylinder block.
While the engine is operated, a tensile force due to vibration and explosion occurs between the cylinder head and cylinder block. However, since the auxiliary member 11 is laminated on the bead-carrying base member 10, especially, the lateral vibration does not work on the base member 10 only, so that a damage to the base member 10 due to the friction thereof on the cylinder head and cylinder block is avoided. The vibration or an impact in the vertical direction, i.e. the perpendicular direction of the surface of the bead-carrying base member 10 is not directly imparted from the cylinder head or cylinder block to both surfaces of the base member 10, and the auxiliary member 11 has a kind of buffer action against the base member 10. Since the folded portions 13 of the auxiliary member 11 do not embrace the bead-carrying base member 10, parts influenced directly by the displacement in the base member due to the compression of the bead 12, and the variation of load and vibration between the cylinder head and cylinder block are not limited to the auxiliary member 11. Accordingly, neither fatigue nor cracks occur in the folded portions 13 of the auxiliary member 11.
Another embodiment of the metallic gasket according to the present invention will now be described with reference to FIGS. 4 and 5. FIG. 4 is a sectional view taken along a line corresponding to the line 44--44 in FIG. 1, and FIG. 5 a sectional view taken along a line corresponding to the line 45--45 or 46--46 in FIG. 1. The constituent elements which are identical with those of the embodiment of FIGS. 2 and 3 of this embodiment are designated by the same reference numerals, and the repetition of the same descriptions is omitted.
Referring to FIGS. 4 and 5, a shim 15 consisting of an annular soft member the thickness of which is uniform in the direction of the whole circumference thereof is inserted between the main portion of the auxiliary member 11 and the folded portions 13 thereof, and embraced by these folded portions 13. The width of the annular body of the shim 15 is set smaller than that of the folded portion 13 to secure the embracing force. The edge parts of the folded portions 13 may be further bent toward the main portion of the auxiliary member 11 to completely enclose the shim 15. Since the shim 15 is provided between the main portion of the auxiliary member 11 and the folded portions 13 thereof, the thickness of the auxiliary member 11 can be regulated at the folded portions 13 by the shim 15. The shim 15 may consist of a soft metal plate just as the auxiliary member 11, or a material the properties of which are identical with those of a soft metal, such as a heat insulating graphite sheet, an aramid beater sheet, a resin or rubber. Moreover, the shim 15 functions as a buffer member, and can be expected to absorb vibration occurring between the cylinder head and cylinder block.
Still another embodiment of the metallic gasket according to the present invention will now be described with reference to FIGS. 6 and 7. FIG. 6 is a sectional view taken along a line corresponding to the line 44--44 in FIG. 1, and FIG. 7 a sectional view taken along a line corresponding to the line 45--45 or 46--46 in FIG. 1. The constituent elements which are identical with those of the embodiment of FIGS. 2 and 3 of this embodiment are designated by the same reference numerals, and the repetition of the same descriptions is omitted.
Referring to FIGS. 6 and 7, a soft member 16 is provided between the main portion of the auxiliary member 11 and the folded portions 13 thereof, which soft member 16 is formed so that the portions thereof which are between adjacent cylinder bore holes 3 are thicker than the other portion thereof. Namely, the thickness t 1 of the portions of the soft member 16 which are between adjacent cylinder bore holes 3 and shown in FIG. 6 is larger than that t 2 (i.e., t 1 >t 2 ) of the portion thereof shown FIG. 7 which is other than the above-mentioned portions. Since the soft member 16 is formed in such a manner, a face-to-face pressure can be secured in accordance with the rigidity of the portions of the bead-carrying base member 10 and auxiliary member 11 which are around the cylinder bore holes 2, 3.
A further embodiment of the metallic gasket according to the present invention will now be described with reference to FIGS. 8 and 9. FIG. 8 is a sectional view taken along a line corresponding to the line 44--44 in FIG. 1, and FIG. 9 a sectional view taken along a line corresponding to the line 45--45 or 46--46 in FIG. 1. The constituent elements which are identical with those of the embodiment of FIGS. 2 and 3 of this embodiment are designated by the same reference numerals, and the repetition of the same descriptions is omitted.
Referring to FIGS. 8 and 9, a soft member 17 is provided between only the parts of the auxiliary member 11 and folded portions thereof that are between adjacent cylinder bore holes 3. The soft member 17 is provided only in the ranges which are shown in FIG. 8, and which are between adjacent cylinder bore holes 3, and it is not provided in the ranges shown in FIG. 9 and other than the ranges between adjacent cylinder bore-holes. Since the soft member 17 is provided only in the ranges between adjacent cylinder bore holes 3, a face-to-face pressure can be secured much better in accordance with the rigidity of the portions of the bead-carrying base member 10 and auxiliary member 11 which are around the cylinder bore holes 2, 3.
These embodiments of the metallic gasket according to the present invention are described relatively to a four-cylinder engine. The engine to which the metallic gasket according to the present invention is applied is not limited to a four-cylinder engine; it can also be applied, of course, to other type of multicylinder engines, such as a V-type six-cylinder engine.
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In the metallic gasket according to the present invention, beads are formed on the circumferential portions of the first cylinder bore-aligned holes in the base member, and folded portions are formed on the auxiliary member by merely folding back the inner edge sections of the second cylinder bore-aligned holes therein so as not to embrace the bead-carrying base member, the auxiliary member being laminated on the side of the base member from which the beads project. In this metallic gasket, the folded portions of the auxiliary member restrict the deformation of the beads to minimize the occurrence of fatigue and cracks in the beads, whereby the sealing function of the gasket is improved with uniform and proper surface pressure distribution maintained. Soft members are provided between the main portion of the auxiliary member and the folded portions thereof so as to secure proper surface pressure distribution in the metallic gasket in accordance with the rigidity of the cylinder head.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/990,386 filed 27 Nov. 2007.
BACKGROUND OF THE INVENTION
[0002] As an emerging technology, phase change materials attracted more and more interest for its applications in manufacturing a new type of highly intergrated nonvolatile memory devices, phase change random access memory (PRAM). PRAM uses the unique behavior of chalcogenide glass, which can be “switched” between two states, crystalline and amorphous, with the application of heat. The crystalline and amorphous states of chalcogenide glass have dramatically different electrical resistivity, and this forms the basis by which data are stored. The amorphous, high resistance state is used to represent a binary 0, and the crystalline, low resistance state represents a 1.
[0003] Although PRAM has not yet reached the commercialization stage for consumer electronic devices, nearly all prototype devices make use of a chalcogenide alloy of germanium, antimony and tellurium (GeSbTe) called GST. The stoichiometry or Ge:Sb:Te element ratio is 2:2:5. When GST is heated to a high temperature (over 600° C.), its chalcogenide crystallinity is lost. Once cooled, it is frozen into an amorphous glass-like state and its electrical resistance is high. By heating the chalcogenide to a temperature above its crystallization point, but below the melting point, it will transform into a crystalline state with a much lower resistance.
[0004] One of the technical hurdles in designing PRAM cell is that in order to overcome the heat dissipation during the switching GST materials from crystalline to amorphous states at certain temperature, a high level of reset current needs to be applied. This heat dissipation can be greatly reduced by confining GST material into contact plugs. This would reduce the reset current needed for the action. Such a design, however, presents challenges for the techniques to form thin layer of GST materials. Since a plug structure is a high aspect ratio one, the conventional deposition method for GST films, or sputtering technique, due to its line-of-sight effect, has been found difficult to fill the plugs or high aspect ratio holes with GST materials. On the other hand, deposition techniques based on chemical reactions such as chemical vapor deposition (CVD) rely on transport and reaction of chemical vapors and do not have the line-of-sight effect. These techniques are better fits for such applications. In particular, the atomic layer deposition (ALD) can produce films with high conformality and chemical composition uniformity. Another technique in between ALD and CVD is so called cyclic CVD that may can be used for such applications.
[0005] To form a Ge—Sb—Te film that has a required stochiometry using CVD or ALD technique, one may need to form Ge, Sb or Te layer alternately followed by annealing. The thickness of each layer (Ge, Sb or Te) can be controlled so that a desired stochiometry ( e.g. 2,2,5 of Ge, Sb and Te) can be achieved in final product. Among these three layers, e.g., Ge, Sb and Te, Te may be the most difficult one to form. Currently available methods to form Te films either need high deposition temperature or plasma assist. However, either from materials and device performance or manufacturing cost, it is always preferred that the deposition can be performed at low temperature and without plasma assistance.
[0006] Hydrogen telluride has been used to prepare metal telluride, such as mercury telluride and cadmium telluride, as semiconductor materials. Dialkyltellurides are also used to make these materials.
[0007] Recently, the development of phase change memory has required the proper tellurium precursors for ALD or CVD deposition of GST films at relatively low temperature. Dialkyltelluride and diaminotellurides have been used. However, these precursors have low reactivity toward the deposition reaction. Sometimes it results low tellurium content in the films than required stoichiometrical composition.
[0008] Synthesis of bis(trialkylsilyl)tellurium has been reported, as has synthesis of other silyltellurium compounds: (Me3Si)3SiTeH.
[0009] This invention discloses methods to form thin Te films and GST films using chemical vapor deposition methods at low temperatures.
BRIEF SUMMARY OF THE INVENTION
[0010] In one aspect, this invention discloses a method to form GST films and Te films using a CVD process at a temperature between 80° C. and 500° C. The Ge, Sb and Te precursors are selected from the group consisting of:
[0000] (R 1 R 2 R 3 Si) 2 Te; (R 1 R 2 R 3 Si)TeR 4 ; (R 1 R 2 R 3 Si)TeN(R 4 R 5 ) (R 1 R 2 N) 3 Sb; (R 1 R 2 N) 4 Ge;
[0000] where R 1-5 are individually an alkyl group or alkenyl group with 1 to 10 carbons as chain, branched, or cyclic, or an aromatic group.
[0011] GST films are deposited from tellurium generated by the reaction of selected silyltellurium compounds with alcohols with a general formula of ROH, where R is an alkyl group with 1 to 10 carbon atoms in a linear, branched, or cyclic form, or an aromatic group, and the consequential reactions with selected aminogermanes and aminoantimony.
[0012] In another aspect, this invention discloses a method to form GST films using an ALD process at a temperature between 80° C. and 500° C. The Ge, Sb and Te precursors are selected from the group consisting of:
[0000] (R 1 R 2 R 3 Si) 2 Te; (R 1 R 2 R 3 Si)TeR 4 ; (R 1 R 2 R 3 Si)TeN(R 4 R 5 ) (R 1 R 2 N) 3 Sb; (R 1 R 2 N) 4 Ge;
[0000] where R 1-5 are individually an alkyl group or alkenyl group with 1 to 10 carbons as chain, branched, or cyclic, or an aromatic group.
[0013] GST films are deposited from tellurium generated by the reaction of selected silyltellurium compounds with alcohols with a general formula of ROH, where R is an alkyl group with 1 to 10 carbon atoms in a linear, branched, or cyclic form, or an aromatic group, and the consequential reactions with selected aminogermanes and aminoantimony.
[0014] In another aspect, this invention discloses a method to form GST films using a cyclic CVD process at a temperature between 80° C. and 500° C. The Ge, Sb and Te precursors are selected from the group consisting of:
[0000] (R 1 R 2 R 3 Si) 2 Te; (R 1 R 2 R 3 Si)TeR 4 ; (R 1 R 2 R 3 Si)TeN(R 4 R 5 ) (R 1 R 2 N) 3 Sb; (R 1 R 2 N) 4 Ge;
[0000] where R 1-5 are individually an alkyl group or alkenyl group with 1 to 10 carbons as chain, branched, or cyclic, or an aromatic group.
[0015] GST films are deposited from tellurium generated by the reaction of selected silyltellurium compounds with alcohols with a general formula of ROH, where R is an alkyl group with 1 to 10 carbon atoms in a linear, branched, or cyclic form, or an aromatic group, and the consequential reactions with selected aminogermanes and aminoantimony.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 . The schematic of deposition apparatus.
[0017] FIG. 2 . FESEM view of a Te film cross section.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention relates to methods of forming thin Te films and GST films. The methods involves two aspects, selection of the Te based precursors, and the deposition techniques to form GST films using Te precursor and other precursors. The depositions are performed at 80° C. to 500° C., preferably 100° C. to 400° C., more preferably 100° C. to 200° C., most preferably 100° C. to 150° C.
The Te Precursors.
[0019] The tellurium precursors can be selected from disilyltellurium, silylalkyltellurium, silylaminotellurium with the general structures of:
[0000] R 1 R 2 R 3 Si) 2 Te (R 1 R 2 R 3 Si)TeR 4 (R 1 R 2 R 3 Si)TeN(R 4 R 5 )
[0000] where R 1 , R 2 , R 3 , R 4 , and R 5 are independently hydrogen, alkyl groups having 1-10 carbons in linear, branched, or cyclic forms without or with double bonds, or aromatic groups.
[0020] Silyltellurium compounds are highly reactive to alcohols or water. These reactions can take place at room temperature or elevated temperature, resulting the generation of elemental tellurium
[0000]
[0021] In an ALD process, the tellurium precursors, alcohols, germanium and antimony precursors, such as (Me 2 N) 4 Ge and (Me 2 N) 3 Sb are introduced to a deposition chamber in any sequence in a cyclic manner by vapor draw or direct liquid injection (DLI). The deposition temperature is preferably between 80° to 500° C.
[0022] The ALD reaction can be illustrated by the following scheme:
[0000]
[0023] Step 1. Tetrakis(dimethylamino)germane is introduced and forms a molecular layer of aminogermane on the surface of the substrate.
[0024] Step 2. Hexamethyldisilyltellurium reacts with aminogermane layer to form Te—Ge bonds with elimination of dimethylaminotrimethylsilane. A Te layer with silyl substituents is formed.
[0025] Step 3. Methanol reacts with remaining silyl groups on tellurium layer to form Te—H bonds and volatile byproduct methoxytrimethylsilane, which is removed by purge.
[0026] Step 4. Tris(dimethylamino)stibane is introduced and forms antimony layer on the top of tellurium layer.
[0027] Step 5. Hexamethyldisilyltellurium is introduced again and forms tellurium layer.
[0028] Step 6. Methanol is introduced again to remove silyl groups on the tellurium.
[0029] An ALD cycle is then completely repeated, potentially many times, until the desired film thickness is achieved. The next cycle starts with Step 1, again, etc.
[0030] The silyltellurium compounds used in this process have the general structures:
[0000] (R 1 R 2 R 3 Si) 2 Te; (R 1 R 2 R 3 Si)TeR 4 ; and (R 1 R 2 R 3 Si)TeN(R 4 R 5 )
[0000] where R 1 ,R 2 ,R 3 ,R 4 and R 5 are individually hydrogen, alkyl groups with 1 to 10 carbons in linear, branched, or cyclic form, or aromatic groups.
[0031] Aminogermanes and aminoantimony used in this process have the general formula:
[0000] (R 1 R 2 N) 4 Ge (R 1 R 2 N) 3 Sb
[0000] where R 1 and R 2 are individually alkyl groups with 1 to 10 carbons in linear, branched, or cyclic form.
[0032] Alcohols used in this process have the general formula:
[0000] ROH
[0000] where R is an alkyl group with 1 to 10 carbons in linear, branched, or cyclic form.
The Film Deposition
[0033] The method described in this invention can be demonstrated using a thin film deposition apparatus illustrated in FIG. 1 . The apparatus consists of the following parts:
A reactor 5 where a substrate is placed, precursor vapors react and form films. The reactor walls and substrate holder can be heated at the same or different temperatures; liquid or solid precursor containers 1 and 2 . The containers may also be heated if needed; the valves 3 and 4 that may switch on or off the vapor flows to the reactor from the precursor containers. A mass flow controller (MFC) unit is used to control when and how much valves 3 and 4 switch; the vacuum pump 8 that pumps out air or precursor vapors from the reactor. A valve 7 switches on/off the pumping line; a vacuum gauge 6 that measures the pressure level within the reactor; an inert gas (Ar or N 2 ) 10 that switches on or off via valve 11 .
[0040] Before the deposition begins, the reactor 5 is filled with inert gas (e.g., Ar or N 2 ) through inlet 10 and then pumped out using a vacuum pump 8 to a vacuum level below 20 mTorr. The reactor is then filled with inlet gas again and the reactor wall and substrate holder are heated to a temperature between 80° C. to 500° C. at which the deposition is set to begin.
[0041] The Te precursor is delivered from precursor container 1 that is heated to a temperature between 30° C. to 100° C. The temperature remains constant during the deposition. The MeOH precursor is delivered from precursor container 2 that is heated to a temperature between 20° C. to 50° C. The temperature also remains a constant during the deposition.
[0042] A CVD process to form Te film is as follows:
Feed Te precursor vapor to the reactor by opening valve 3 ; Close the valve 3 to stop Te vapor from entering the reactor; Feed MeOH vapor to the reactor by opening valve 4 ; Close the valve 4 to stop MeOH vapor from entering the reactor; Te precursor vapor reacts with MeOH vapor within the reactor to form Te film on a substrate.
[0048] An ALD process to form Te film is as follows:
Close the reactor to vacuum pump 8 by closing valve 7 ; Feed Te precursor vapor to the reactor a pulse of 0.1 seconds to 2 seconds by switching and off valve 3 ; Feed Ar or N 2 into the reactor through line 10 and purge the reactor for 0.1 to 5 seconds by pumping out Ar or N 2 using vacuum pump 8 ; Close the reactor to vacuum pump 8 by closing valve 7 ; Feed MeOH precursor vapor to the reactor a pulse of 0.01 seconds to 0.1 seconds by switching and off valve 4 ; Feed Ar or N 2 into the reactor through line 10 and purge the reactor for 0.1 to 5 seconds by pumping out Ar or N 2 using vacuum pump 8 ; Close the reactor to vacuum pump 8 by closing valve 7 ; Repeat the above steps from many times. The number of the cycles is preset according to the film thickness that is predetermined.
[0057] A cyclic CVD process to form Te film is as follow:
Close the reactor to vacuum pump 8 by closing valve 7 ; Feed Te precursor vapor to the reactor a pulse of 2 seconds to 20 seconds by switching and off valve 3 ; Feed MeOH precursor vapor to the reactor a pulse of 0.2 seconds to 10 seconds by switching and off valve 4 ; Pump the reactor by opening valve 7 using vacuum pump 8 ; Repeat the above steps from many times. The number of the cycles is preset according to the film thickness that is predetermined.
[0063] The GST (Ge—Sb—Te) films are formed by repeating the processes for Ge and Sb, respectively. The processes for the growth of Ge and Sb are similar to that for Te.
EXAMPLE 1
Synthesis of Hexamethyldisilyltellurium
[0064] 1.28 g (0.01 mol) 200 mesh tellurium powder, 0.48 g (0.02 mol) lithium hydride, and 40 ml tetrahydrofuran (THF) were placed in a 100 ml flask. With stirring, the mixture was refluxed for 4 hours. All black powder of tellurium disappeared, and a muddy color precipitate was formed. Then, the mixture was cooled down to −20° C.; 2.2 g (0.02 mol) trimethylchlorosilane was added. The mixture was allowed to warm up to room temperature. After stirring for 4 hours, the mixture was filtered under inert atmosphere. The solvent was removed by distillation. Hexamethyldisilyltellurium was purified by vacuum distillation, b.p. 50° C. at 2.5 mmHg.
EXAMPLE 2
Synthesis of Tetramethyldisilyltellurium
[0065] 3.84 g (0.03 mol) 200 mesh tellurium powder, 1.38 g (0.06 mol) sodium, 0.77 h (0.006 mol) naphthalene, and 50 ml THF were placed in a 100 ml flask. The mixture was stirred at room temperature for 24 hours. All black powder of tellurium and sodium disappeared, and a muddy color precipitate was formed. Then, the mixture was cooled down to −20° C.; 5.77 g (0.06 mol) dimethylchlorosilane was added. The mixture was allowed to warm up to room temperature. After stirring for 4 hours, the mixture was filtered under inert atmosphere. The solvent was removed by distillation. Tetramethyldisilyltellurium was purified by vacuum distillation, B.P. 50° C. at 4 mmHg.
EXAMPLE 3
Synthesis of Trimethylsilyl-t-butyltellurium
[0066] 6.4 g (0.05 mol) 200 mesh tellurium powder, 100 ml diethyl ether, and 20 ml 2.5 M t-butyllithium in hexane were added to a 250 ml flask. At 0° C., the mixture was stirred for 8 hours. All black powder of tellurium disappeared, and a muddy color precipitate was formed. To this mixture, 5.4 g (0.05 mol) trimethylchlorosilane was added. The mixture was allowed to warm up to room temperature. After stirring for 1 hour, the mixture was filtered under inert atmosphere. The solvent was removed by distillation. Trimethylsilyl-t-butyltellurium was purified by vacuum distillation.
EXAMPLE 4
Synthesis of Di-isopropylaminotrimethylsilyltellurium
[0067] A solution of 5.05 g (0.05 mol) di-isopropylamine in 50 ml THF was cooled to −20° C. 20 ml of 2.5M n-butyllithium in hexane was added. After the reaction mixture was warmed to room temperature, 6.4 g (0.05 mol) 200 mesh tellurium powder was added. The mixture was stirred at room temperature for 24 hours. All black powder of tellurium disappeared, and a muddy color precipitate was formed. Then, the mixture was cooled down to −20° C.; 5.4 g (0.05 mol) trimethylchlorosilane was added. The mixture was allowed to warm up to room temperature. After stirring for 4 hours, the mixture was filtered under inert atmosphere. The solvent was removed by distillation. Di-isopropylaminotrimethylsilyltellurium was purified by vacuum distillation.
EXAMPLE 5
Generation of Elemental Tellurium
[0068] 0.05 g hexamethyldisilyltellurium was placed on the bottom of a 100 ml pyrex glass flask filled with nitrogen and fitted with a rubber septem. 0.1 g of methanol was added slowly with a syringe. A shiny black film stared to deposit inside the glass wall of the flask. After a few minutes the entire flask interior was coated with a black tellurium film.
EXAMPLE 6
Deposition and Characterization of Te Film
[0069] Thin films of Te were deposited using the method described in this invention. Specifically, hexamethyldisilyltellurium and methanol were used as precursors to form pure Te film. Since TiN is typically used for metal contacts in GST memory cells, the Si (100) wafers coated with 100 nm TiN film by sputtering technique were used as the substrates for Te film deposition. The container for Te precursor (hexamethyldisilyltellurium) was heated to a temperate at 50° C., while the container for methanol was kept at 20° C. The substrate temperature during the deposition was kept at 100° C. The deposition reactor was first pumped down to a base pressure of about 2 mT, followed by flashing nitrogen at least five times to remove any residual gases in the reactor. A working pressure of 20 mT was maintained within the deposition reactor during the deposition. The flow rate of the hexamethyldisilyltellurium was kept at 0.06 g/min, while the flow rate of methanol was kept at 0.4 g/min.
[0070] After the deposition was complete, the film was inspected using a field emission electron scanning microscope (FESEM) for its thickness and morphology. The SEM work was performed using a Hitachi S-4800 field emission SEM operating at 2 kV accelerating voltage for SEM. The images were collected using the upper secondary electron detector which produces the best resolution. A typical cross section view of the Te film deposited as described above is shown in FIG. 2 . As can be seen from FIG. 2 , about 80 nm thick Te film is formed on TiN layer which is between Si (100) substrate and Te film. The Te film is also very uniform.
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The present invention is a process of making a germanium-antimony-tellurium alloy film using a process selected from the group consisting of atomic layer deposition and chemical vapor deposition, wherein a silyltellurium precursor is used as a source of tellurium for the alloy film and is reacted with an alcohol during the deposition process.
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This is a divisional of application Ser. No. 07/762,931 filed Sep. 19, 1991, now pending.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lock mechanism in which, by pressing an openable cover of an audio-apparatus, an audio-apparatus accommodating case or the like, or an openable member of such as a door of a box or the like, the openable cover or member is engaged with or disengaged from a main body, and to a latch device in which a latch body is retained in a pushed-in state or a withdrawn state in a housing so as to be provided with the same function as that of the lock mechanism.
2. Description of the Related Art
In a typical audio apparatus or the like, a latch device L is provided on an openable cover so as to retain the openable cover, as shown in FIG. 4.
As shown in the drawing, the latch device L is arranged such that each time a latch body 10 is pressed by a striker 34 in the direction of arrow A, a tracing member provided in a housing 14 moves halfway in a heart-shaped circulatory cam groove formed in the latch body 10, thereby allowing the latch body 10 to be retained in the housing 14 alternatively in a state in which the latch body 10 is pushed in and in a state in which it is withdrawn. Concurrently, as shown in FIG. 5, while a pair of arms 50 formed on the latch body 10 are respectively being pressed by a pair of rectangular frames 40 of the housing 14, the striker 34 fixed to the openable cover is clamped or released, thereby setting the openable cover in a closed state or in an openable state.
As shown in FIGS. 4 and 5, each of the arms 50, which are generally provided on the latch body 10, comprises a holder portion 50A for clamping the striker 34 and a hinge portion 50B serving as a center of rotation of the holder portion 50A. The arms 50 are formed of a flexible material such as nylon so as to facilitate the bending of the hinge portions 50B and reduce their frictional resistance with respect to the rectangular frames 40.
However, there has been a drawback in that if a large tensile load (acting in the direction of arrow B in FIG. 5) is continuously applied to the striker 34 while the respective holder portions 50A of the arms 50 are holding the striker 34, since the hinge portions 50A are flexible, the hinge portions 50B become elongated or offset in the direction in which the holder portions 50A are spaced apart from each other, thus causing the striker 34 to come off the holder portions 50A.
To give a more detailed description, when a tensile force W shown in FIG. 5 acts on each holder portion 50A via the striker 34, if the length of the arm is assumed to be L, a bending moment M (M=WL/2) acts on each hinge portion 50B. Accordingly, each hinge portion 50B rotates in the direction in which the holder portions 50A are spaced apart from each other. In addition, since a tensile force σ(σ=M/Z, Z: coefficient of a cross section) due to the bending moment M acts on each hinge portion 50B, the hinge portions 50B become elongated in the direction of arrow B. As a result, the holder portions 50A become offset in the direction of arrow B while becoming spaced apart from each other. Hence, there has been the drawback that the striker 34 is liable to come off the holder portions 50A.
In addition, since an outer side of the hinge portion 50B is formed as a curved portion D, there has been another drawback in that if the tensile force W acts, the curved portion D is pulled, so that the hinge portion 50B becomes elongated.
In a typical latch device such as the one shown in FIG. 14, a rear end portion 182B of a tracing member 182 moving in a circulatory cam groove 180 in a circulatory manner is rotatably inserted in a fitting hole 184 formed in the unillustrated housing. In addition, the tracing member 182 is pressed by a pressing leaf spring 188 secured to the housing by means of a screw 186 such that the tracing member 182 will not come off the fixing hole 184.
However, with the above-described structure for fitting the tracing member 182, the tracing member 182 cannot be fit in the housing from the outside thereof. For this reason, it has been necessary to fixedly hold the tracing member in the housing in advance, and then to allow a tip portion 182A of the tracing member 182 to be fitted into the circulatory cam groove 180 formed in a latch body 190 which is inserted into the rear portion of the housing.
For this reason, in the event that the tip portion 182A of the tracing member 182 is shaken during the assembling operation, the tip portion 182A cannot be inserted into the circulatory cam groove 180, and the tip portion 182A of the tracing member 182 is brought into contact with a different portion of the latch body 190. Hence, a drawback has been encountered in that the latch body 190 cannot be inserted into the housing, so that the assembling of the latch device has been troublesome. In addition, a pressing member (e.g., a pressing leaf spring 188) is required for pressing the tracing member 182, with the result that the number of component parts used disadvantageously increases and the assembling efficiency has been low.
Meanwhile, in a center cluster portion of an automobile, a push-open type ash pan is provided which automatically slides out upon pressing of its cover.
This push-open type ash pan is provided with a lock mechanism 280 as shown in FIG. 30. This lock mechanism 280 is arranged as follows: If a front face portion of the unillustrated ash pan is pushed in the direction of arrow R, a tracing member 284 fixed to a rear end portion of the ash pan is inserted into a heart-shaped circulatory cam groove 282 formed in a box. The inserted tracing member 284, when thus pressed, moves in the heart-shaped circulatory cam groove 282 in a circulating manner, and when the tracing member 284 engages a recessed (cusp) portion 292 of the heart-shaped circulatory cam groove 282, the tracing member 284 retains the ash pan in a state in which the ash pan is pushed in.
In the lock mechanism 280 shown in FIGS. 30 and 31, a stepped portion 288 is provided so that the tracing member 284 can circulate in a set direction (in the direction of arrow Q) in the circulatory cam groove 282, so as to prevent the tracing member 284 from circulating in an opposite direction. In addition, an urging means 290 is provided separately for urging a tip portion 286 of the tracing member 284 vertically toward the bottom surface of the circulatory cam groove 282 to ensure that the tracing member 284 will circulate with its tip Portion 286 brought positively into sliding contact with the bottom surface of the circulatory cam groove 282.
With the mechanism in which the tip portion 286 of the tracing member 284 is caused to slide on the bottom surface of the circulatory cam groove 282, a shortcoming has been experienced in that, owing to the friction of the bottom surface of the groove with the tip portion 286 of the tracing member 284, the circulatory cam groove 282 sometimes becomes worn or deformed, and the stepped portion 288 is scraped off, thereby causing the tracing member 284 to circulate in the opposite direction.
In the state in which the ash pan is pushed in, the tracing member 284 is retained at the recessed portion 292 formed in the circulatory cam groove 282, and the state in which the ash pan is pushed in is maintained against the urging force of an unillustrated compression coil spring. However, since the urging force of the compression coil spring is supported at one recessed portion 292, the recessed portion 292 is liable to become damaged. Hence, the rupture strength of the lock mechanism 280 has been low.
In addition, since the tip portion 286 of the tracing member 284 is urged towards the bottom surface of the circulatory cam groove 282, there is a need to provide the urging means 290 separately, so that the number of component parts used disadvantageous increases and the assembling efficiency has been low.
Although the tracing member 284 is usually formed of a metal material into the shape of a lever, there have been cases where if fabrication accuracy at the time of its formation is poor, the tracing member 284 scrapes off the bottom surface of the circulatory cam groove 282, or the tracing member 284 undergoes deformation due to its frictional resistance with respect to the circulatory cam groove 282.
In the case of a latch device employing the above-described lock mechanism 280, since it is necessary to form the stepped portion 288 in the circulatory cam groove 282 provided in the latch body, and to provide the tracing member 284 with the urging means 290, the housing which accommodates the latch body and the tracing member is required to be provided with a certain thickness. For this reason, it has been difficult to make the latch device thin beyond this restriction.
SUMMARY OF THE INVENTION
In view of the above circumstances, an object of the present invention is to provide a latch device featuring an arm structure wherein the bending performance of a pair of hinge portions is excellent and the hinge portions do not undergo deformation even with respect to a large tensile force.
Another object of the present invention is to provide a latch device featuring a tracing-member fitting structure which allows the number of component parts used to be reduced, which facilitates the assembly of the tracing member, and Which provides the trace member with a large supporting strength.
Still another object of the present invention is to provide a lock mechanism having a smaller number of component parts used, capable of preventing the wear of a circulatory cam groove, and having large rupture strength.
A further object of the present invention is to provide a thin latch device making use of the lock mechanism.
In accordance with a first aspect of the present invention, an arm structure of a latch device for causing an openable member to engage with or disengage from a main body is comprised of: a housing fitted on the main body; a striker fitted on the openable member; and a latch body which is retained by the housing in a state in which the latch body is pushed into the housing and in a state in which the latch body is withdrawn in the housing, the latch body having a pair of arms for clamping the striker by rotating in a mutually approaching direction, wherein the center of rotation of each of the arms is formed on substantially the same line as a line of action of a force acting on a retaining surface of each of the arms for retaining the striker relative to a force acting in a direction in which the striker is released with the striker clamped by the arms.
In accordance with a second aspect of the present invention, a tracing-member fitting structure of a latch device for causing an openable member to engage with or disengage from a main body is comprised of: a housing fitted on the main body; a latch body accommodated in the housing, the latch body being urged in a direction in which the latch body is withdrawn, and the latch body being retained by the housing in a state in which the latch body is pushed into the housing and in a state in which the latch body is withdrawn in the housing; a circulatory cam groove formed on the latch body; a tracing member for alternately maintaining the state in which the latch body is pushed into the housing and the state in which the latch body is withdrawn in the housing, by circulating in the circulatory cam groove each time an operation of pushing in the latch body is effected; a fitting hole formed in the housing and allowing a distal end portion of the tracing member to be fitted in the housing; a guide hole provided in the housing, communicating with the fitting, and adapted to guide the movement of the tracing member; a slanted guide surface provided in the housing, communicating with the guide hole, and adapted to guide a rear end portion of the tracing member into the housing; and a fitting groove provided in the housing, formed continuously with the slanted guide surface, and adapted to receive the rear end portion of the tracing member.
In accordance with a third aspect of the present invention, a lock mechanism which has the function of causing an openable member to engage with o disengage from a main body and includes a first lock member and a second lock member is comprised of: a pair of circulatory guide paths formed on different portions of the first lock member and having mutually different configurations for guiding; and resilient tracing means disposed in the second lock member and adapted to move relative to the first lock member so as to alternately maintain a state of engagement with the first lock member and a state of disengagement from the first lock member, wherein the tracing means traces the pair of circulatory guide paths through movement thereof relative to the first lock member and resilient restoring force of the tracing means occurring as the tracing means is pressed relatively by side walls of the pair of circulatory guide paths by means of the relative movement, the tracing means being in a state of noncontact with bottom surfaces of the circulatory guide paths during tracing.
In accordance with a fourth aspect of the present invention, a latch device for causing an openable member to engage with or disengage from a main body is comprised of: a housing fitted on the main body; a latch body accommodated in the housing, the latch body being urged in a direction in which the latch body is withdrawn, and the latch body being retained by the housing in a state in which the latch body is pushed into the housing and in a state in which the latch body is withdrawn in the housing; a pair of circulatory guide paths formed on different portions of the latch body and having mutually different configurations for guiding; resilient tracing means disposed in the housing and adapted to alternately maintain the state in which the latch body is pushed into the housing and the state in which the latch body is withdrawn in the housing, by circulating in the circulatory guide paths each time an operation of pushing in the latch body is effected, wherein the tracing means traces the pair of circulatory guide paths through the pushing-in operation and resilient restoring force of the tracing means occurring as the tracing means is pressed relatively by side walls of the pair of circulatory guide paths by means of the pushing-in operation, the tracing means being in a state of noncontact with bottom surfaces of the circulatory guide paths during tracing.
In the above-described arm structure of the latch device in accordance with the first aspect of the invention, when the openable member is closed, the latch body is pressed by the striker and is retained in pushed-in state in the housing secured to the main body of an apparatus. At this juncture, the pair of arms disposed on the latch body are pressed by the frame of the housing, and rotate in a mutually approaching direction, thereby clamping the striker.
With the striker held by the arms, if a force acts on the striker in a direction in which the striker is released from the arms, the force of the striker acting in the direction in which the striker is released acts on a retaining surface of each of the arms for retaining the striker. However, since the center of rotation of each of the arms is located on the substantially the same line as the line of action of a force acting on the retaining surface of the arm, bending moment does not act on the center of rotation. Accordingly, since only the tensile force acts on the center of rotation, there occurs no rotating force acting in the direction in which the arms are spaced apart from each other, nor a tensile force due to the bending moment.
Furthermore, since the outer side of a central portion of rotation is arranged to be parallel with the line of action of the tensile force, an elongation of a hinge Portion is difficult to occur.
In the above-described tracing-member fitting structure of the latch device in accordance with the second aspect of the invention, the tracing member is fitted as follows.
The tip portion of the tracing member is fitted into the housing through a fitting hole formed in the housing of the latch device. Then, with the tip portion of the tracing member inserted in the housing, the rear end portion of the tracing member is moved to a guide hole communicating with the fitting hole. The rear end portion of the tracing member which has moved to the guide hole is guided to a slanted guide surface communicating with the guide hole, and is pushed in until it reaches a fitting groove. At this juncture, since a portion of communication between the fitting groove and the slanted guide surface is formed to be slightly smaller than the outside diameter of the tracing member, the tracing member is fitted in the fitting groove in such a manner as to expand this portion of communication between the fitting groove and the slanted guide surface. Accordingly, once the tracing member is fitted in the fitting groove, the tracing member is prevented from coming off easily.
Furthermore, since the fitting groove and the slanted guide surface serve to integrally support the tracing member with respect to a tensile force acting thereon, this arrangement exhibits large supporting strength.
In the lock mechanism in accordance with the third aspect of the invention, when the tracing member disposed in the second lock member is inserted into a pair of circulatory guide paths provided in the first lock member, the tracing member circulates the circulatory guide paths in a fixed direction by means of its movement relative to the first lock member.
At this juncture, the tip portions of the tracing member are inserted in such a manner that they will not come into contact with the bottom surfaces of the circulatory guide paths of the first lock member, and only the side surface portions of the tip portions of the tracing member are brought into contact with the side walls of the circulatory guide paths, respectively. Therefore, the bottom surfaces of the circulatory guide paths are not worn by the tracing member. Meanwhile, since the configurations of the pair of circulatory guide paths are mutually different, the tracing member tracing the circulatory guide paths circulates the circulatory guide paths while it is pressed by the side walls of the circulatory guide paths and a resilient restoring force is hence being imparted thereby through its movement relative to the first lock member. For this reason, the tracing member is urged in the circulating direction by the resilient restoring force of the tracing member. Hence, even if stepped walls for preventing the backward movement of the tracing member in the circulatory guide paths are not provided, the tracing member circulates in the fixed direction without being moving backwardly.
Furthermore, since the tracing member is inserted in the pair of circulatory guide paths, the holding of the tracing member is effected at two portions of the second lock member.
In the latch device in accordance with the fourth aspect of the invention, the tracing member circulates in the circulatory guide paths each time the operation of pushing in the latch body is effected, so as to alternately hold the latch body in the state of being pushed in the housing and in the state of being withdrawn from the housing.
Since the arrangements of the tracing member and the circulatory guide paths are the same as those of the third aspect, a description of the operation will be omitted.
As described above, with the arm structure of the latch device in accordance with the first aspect of the invention, even if a large tensile force acts on the striker when the striker is clamped, no bending moment occurs in the hinge portions. Accordingly, the hinge portions are prevented from rotating in the direction in which the holder portions are spaced apart from each other, and the hinge portions are prevented from becoming offset in the pulling direction.
Furthermore, since the outer side of each of the hinge portions is formed to be parallel with the line of action of the tensile force, the hinge portions are difficult to become elongated.
For this reason, since the structure provided is such that even if the arms are formed of a flexible material, the offsetting of the holder portions are prevented, the striker is prevented from coming off the holder portions.
With the tracing-member fitting structure of the latch device in accordance with the second aspect of the invention, no fixing member is required separately for fixing the tracing member in the housing, so that the number of component parts used can be reduced, and fitting performance improves. In addition, since the tracing member can be fitted from outside the housing after the latch body has been inserted into the housing, the assembling of the tracing member is facilitated.
Furthermore, since the opposite sides of the tracing member are supported by the fitting groove formed integrally with ribs provided in the housing, it is possible to provide a latch device having large strength for supporting the tracing member.
With the lock mechanism in accordance with the third aspect of the invention and the latch device in accordance with the fourth aspect of the invention, since the arrangement provided is such that the side walls of the circulatory guide paths are traced by the side surfaces of distal end portions of the tracing member, the bottom surfaces of the circulatory guide paths are prevented from becoming worn. In addition, since it is unnecessary to provide an urging means separately, the number of component parts used can be reduced.
Since the tracing movement in the opposite direction to the circulating direction is prevented by making use of the resilient restoring force of the tracing member, i is unnecessary to form steps on the circulatory guide paths, so that the overall structure can be made compact.
In addition, since the prevention of the coming off of the tracing member is effected at two portions in the circulatory guide paths, the supporting strength is large, so that the rupture strength of the lock mechanism can be increased.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view illustrating a state before a pair of arms in accordance with an embodiment of a first aspect of the invention clamps a striker;
FIG. 2 is a plan view illustrating a state after the pair of arms in accordance with the embodiment of the first aspect of the invention has clamped the striker;
FIG. 3 is an exploded perspective view of a latch device having the arms in accordance with the embodiment of the first aspect of the invention;
FIG. 4 is a plan view illustrating a state before conventional arms clamp the striker;
FIG. 5 is a plan view illustrating a state after the conventional arms have clamped the striker;
FIG. 6 is a rear view of the latch device illustrating a tracing-member fitting structure of the latch device in accordance with a first embodiment of a second aspect of the invention;
FIG. 7 is a perspective view illustrating the tracing member fitting structure of the latch device in accordance with the first embodiment of the second aspect of the invention;
FIG. 8 is an exploded perspective view of the latch device in accordance with the first embodiment of the second aspect of the invention;
FIG. 9 is a cross-sectional view of the latch device in accordance with the first embodiment of the second aspect of the invention;
FIGS. 10 to 12 are partial cross-sectional views illustrating the procedure of fitting a tracing member in a tracing-member fitting mechanism of the latch device in accordance with the first embodiment of the second aspect of the invention;
FIG. 13 is a perspective view illustrating the tracing-member fitting structure of the latch device in accordance with a second embodiment of the second aspect of the invention;
FIG. 14 is an exploded perspective view illustrating a component-parts fitting structure of a conventional latch device;
FIG. 15 is an overall perspective view of a lock mechanism in accordance with a first embodiment of a third aspect of the invention;
FIG. 16 is a perspective rear view of a push-type ash pan having the lock mechanism in accordance with the first embodiment of the third aspect of the invention;
FIGS. 17 to 25 are plan views of the operating state of the tracing member with respect to a circulatory guide path of the lock mechanism during one cycle in accordance with the first embodiment of the third aspect of the invention;
FIG. 26 is an overall perspective view of the lock mechanism in accordance with a second embodiment of the third aspect of the invention;
FIG. 27 is an overall perspective view of the latch device in accordance with an embodiment of a fourth aspect of the invention;
FIG. 28 is a partially cut-away perspective view of the latch device in accordance with the fourth aspect of the invention;
FIG. 29 is a cross-sectional view of the latch device in accordance with the fourth aspect of the invention taken along the line 29--29 of FIG. 27;
FIG. 30 is a plan view of a circulatory cam groove and a tracing member of a conventional lock mechanism; and
FIG. 31 is a cross-sectional view of a conventional lock mechanism 280 taken along the line 31--31 of FIG. 16.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Overall Configuration of Latch Mechanism
As shown in FIG. 3, a latch device L comprises a latch body 10 and a housing 14 for accommodating a tracing member 12 therein.
The housing 14 has a box-shaped configuration of a predetermined thickness, and the latch body 10 is inserted into an opening 16 formed at a longitudinal end of the housing 14. A rectangular frame 40 for fixing the housing 14 to an audio apparatus or the like is formed in such a manner as to define the opening 16. A pair of projections 20 are formed on opposite side surfaces of the housing 14, respectively, in correspondence with the laterally projecting portions of the rectangular frame 40. This arrangement is provided to allow an unillustrated fixing plate to be clamped by the laterally projecting portion of the rectangular frame 40 and the projection 20 on each side of the housing 14, so as to fix the housing 14 to the fixing plate.
The latch body 10 which is inserted into the housing 14 is substantially rectangular parallelepipedal in configuration, and a circular hole 22 is formed along the longitudinal direction of the latch body 10, extending from an insertion end thereof. A compression coil spring 24 is accommodated in the circular hole 22. A portion of the compression coil spring 24 projects from the circular hole 22 and is fitted in a spring-bearing hole 26. As a result, the latch body 10 is constantly urged by the compression coil spring 24 in the direction in which the latch body 10 is pulled out of the housing 14.
A recessed portion 28 is formed on each of the top and bottom surfaces of the latch body 10. A circulatory cam groove 30 is formed in each of the recessed portions 28. Each tip portion 12A of the tracing member 12 is inserted into the respective circulatory cam groove 30 and is adapted to move in the circulatory cam groove 30 in a circulating manner while being brought into contact with the wall surface of the circulatory cam groove 30, so as to retain the latch body 10 in its pushed-in state.
A projection 32 is formed on the top surface of the latch body 10, and is fitted in an elongated guide hole 31 formed in the housing 14. As a result, as the projection 32 moves in the elongated guide hole 31, the latch body 10 is reciprocatively moved relative to the housing 14. Also, as the projection 32 is brought into contact with one end of the elongated guide hole 31, further movement of the latch body 10 in the direction in which it is pulled out is prevented against the urging force of the compression coil spring 24.
The first aspect of the present invention relates to the structure of the arms of the latch device. An embodiment thereof will be described hereinunder.
As shown in FIG. 1, a pair of arms 36 for clamping a striker 34 are provided on the latch body 10. Each arm 36 comprises a holder portion 36A and a hinge portion 36B. The holder portions 36A in their free state, i.e., before the latch body 10 is pushed into the housing 14 in the direction of arrow A, are formed to be spaced apart from each other. Formed at the distal end of the holder portion 36A is a hook portion 36C projecting perpendicularly to the axis of the holder portion 36A. These hook portions 36C are adapted to abut against an enlarged-diameter portion 34A of the striker 34 so as to prevent the striker 34 from being pulled out.
The hinge portions 36B with a small thickness are formed at the respective root portions of the arms 36. These hinge portions 36B serve as fulcrums when the holder portions 36B rotate in the mutually approaching direction.
As shown in FIG. 2, in the state in which the striker 34 is held by the holder portions 36A, each of the hinge portions 36B is formed in such a manner as to be located on an extension of a line of action C of a tensile force W in the direction of arrow B acting on the hook portion 36C via the striker 34.
In addition, an outer side E of each of the hinge portions 36B is formed in such a manner as to be parallel with the line of action C of the tensile force.
The operation of this embodiment will be described hereinunder.
As shown in FIG. 1, when the latch body 10 is not pushed in by the striker 34, the holder portions 36A of the arms 36 are spaced apart from each other.
Then, as shown in FIG. 2, when a central portion 10A of the latch body 10 is pushed in the direction of arrow A by the striker 34, the latch body 10 is accommodated in the housing 14. Concurrently, as the outer sides of the holder portions 36A are pressed by the rectangular frame 40, and the hinge portions 36B, the holder portions 36A rotate in the mutually approaching direction with the hinge Portions 36B as the fulcrums. For this reason, the striker 34 is clamped by the holder portions 36A, thereby retaining the openable cover.
Next, if the large tensile force W (acting in the direction of arrow B) acts on the striker 34 with the striker 34 thus held, a tensile for W/2 acts on the mutually abutting portions of the enlarged-diameter portion 34A and the hook portion 36C. Although this tensile force W/2 acts on each hinge portion 36C, since the hinge portion 36B is not located on the line of action C of the tensile force W/2, no bending moment occurs in the hinge portions 36B.
Accordingly, the hinge portions 36B do not rotate in the direction in which the holder portions 36A are spaced apart from each other, and the tensile force resulting from the bending moment does not occur in the hinge portions 36B. The hinge portions 36B are prevented from becoming offset in the direction of arrow B insofar as the tensile force W/2 does not exceed the allowable tensile stress of each arm 36.
Even if the hinge portion 36B is slightly offset from the extension of the line of action C, the outer side E of the hinge portion 36B is formed in such a manner as to be parallel with the line of action C of the tensile force. For this reason, since there is no leeway in which the curved portion D is elongated in the manner of a hinge portion 50B shown in FIG. 5, the hinge 36B is prevented from being elongated. It should be noted that the configuration of the arm 36 is not confined to the configuration shown in this embodiment, and it suffices if the structure provided is such that, with the striker 34 held by the holder portions 36B, each hinge portion 36B is located on the line of action of the tensile force acting on the holder portion 36A.
A description will now be given of a first embodiment of a second aspect of the present invention.
FIGS. 6 and 7 illustrate a tracing-member fitting structure 110 of the latch device in accordance with the first embodiment of the second aspect of the invention.
A housing 14 has a box-shaped configuration of a predetermined thickness, and a rectangular through hole 117 is formed in a rear wall 114 of the housing 14 (see FIG. 6). As shown in FIG. 6, in this through hole 117, a substantially T-shaped support piece 115 projects from the left-hand side of the drawing toward the center of the through hole 117, while a tongue piece 124 projects from the right-hand side of the drawing toward the center of the through hole 117.
As viewed in the drawing, an upper and a lower space which are each defined between the head portion of the T-shaped support piece 115 projecting inwardly in the through hole 117 and the left-hand side of the through hole 117 serve as fitting holes 116 into which tip portions 12A (see FIG. 8) of the tracing member 12 are inserted. Meanwhile, as viewed in the drawing, an upper and a lower space which are respectively defined between an upper tip of the head portion of the T-shaped support piece 115 and an upper side of the through hole 117 and between a lower tip of the head portion of the support piece 115 and a lower side of the through hole 117 communicate with an upper end of the upper fitting hole 116 and a lower end of the lower fitting hole 116, respectively. Together with the fitting holes 116, these upper and lower spaces respectively form substantially L-shaped through-hole portions for guiding a rear end portion 12B (see FIG. 8) of the tracing member 12, and are formed as guide holes 118 for guiding the rear end portion 12B (see FIG. 8) of the tracing member 12.
A portion of the head portion of the T-shaped support piece 115 facing the right-hand side of the through hole 117 is provided with a slanted surface such that the distance between the same and the right-hand side of the through hole 117 becomes smaller in the direction in which the tracing member 12 is inserted. This slanted portion is formed as a guide plate 120 for guiding the rear end portion 12B of the tracing member 12 into the housing 14 (see FIG. 9). A pair of arcuate fitting grooves 122 for holding the rear end portion 12B of the tracing member 12 are formed at an innermost end portion of the guide plate 120, i.e., at the portion where the distance between the guide plate 120 and the right-hand side of the through hole 117 is the smallest. In addition, the inner half peripheries of the pair of fitting grooves 122 are respectively formed in a pair of parallel ribs 128 provided on the housing 14. The tensile force of the tracing member 12 acting in the direction of arrow F is supported by these ribs 128 (see FIG. 7).
As shown in FIG. 7, a curved portion 124A whose rear end in the through hole 117 projects toward the guide plate 120, as shown in FIG. 10, is formed on the tongue piece 124 disposed between the pair of ribs 128 and projecting in the direction of narrowing the inlet portion of the fitting grooves 122. An end portion of the curved portion 124A of the tongue piece 124 forms a quarter arc portion 124B of each of the fitting grooves 122. By virtue of this quarter arc portion 124B, together with the half arc portions formed in the fitting grooves 122, the coming off of the rear end portion 12B of the tracing member 12 is prevented (see FIG. 9).
Next, a description will be given of the latch device provided with the above-described structure for fitting the tracing member. As shown in FIG. 8, the structures of the latch body 10, the external configuration of the housing 14, and the compression coil spring 24 are the same as those described with respect to the above-described embodiment of the first aspect. Therefore, these component parts and their portions will be denoted by the same reference numerals, and a description thereof will be omitted here.
The recessed portion 28 is formed on each of the top and bottom surfaces of the latch body 10. Circulatory cam grooves 30, 148 (see FIG. 9) are respectively formed in the recessed portions 28. The tip portions 12A of the tracing member 12 are respectively inserted into the circulatory cam grooves 30, 148 and are adapted to move in the circulatory cam grooves 30, 148 in a circulating manner while being brought into contact with the respective wall surfaces of the circulatory cam grooves.
The tracing member 12 has a substantially C-shaped configuration formed by cutting off a portion of a ring. The gap between the tip portions 12A is set to be greater than the distance between the bottom surfaces of the circulatory cam grooves 30, 148.
The projection 32 is formed on the top surface of the latch body 10, and is fitted in the elongated guide hole 31 formed in the housing 14. As a result, as the projection 32 moves in the elongated guide hole 31, the latch body 10 is reciprocatively moved relative to the housing 14. Also, as the projection 32 is brought into contact with one end of the elongated guide hole 31, further movement of the latch body 10 in the direction in which it is pulled out is prevented against the urging force of the compression coil spring 24.
As shown in FIG. 9, the pair of arms 36 are provided on the latch body 10 on the side away from the side of insertion into the housing 14, and their distal ends are spaced apart from each other. An enlarged-diameter end portion 34B of the striker 34 secured to the unillustrated openable cover is inserted between the arms 36 to press a central portion 10A of the arms 36, so as to push the latch body 10 into the housing 14. When the latch body 10 is thus pushed in by the striker 34, the outer sides of the arms 36 are brought into contact with the rectangular frame 40, so that the arms 36 rotate in the mutually approaching direction with the hinges 36B serving as fulcrums. As a result, the enlarged-diameter end portion 34B of the striker 34 is held by the arms 36, thereby closing the openable cover.
A description will now be given of the procedure of assembling the latch device having the structure for fitting the tracing member in accordance with the first embodiment of the second aspect of the invention.
First, the compression coil spring 24 is inserted into the circular hole 22 formed in the latch body 10 or into the spring-bearing hole 26 provided in the housing 14 (see FIG. 8).
The latch body 10 is then pushed into the housing 14 with the compression coil spring 24 being urged, and the projection 32 is inserted into the elongated guide hole 31 formed in the housing 14, thereby accommodating the latch body 10 in the housing 14 (see FIGS. 8, 9).
As shown in FIG. 10, the tip portions 12A of the tracing member 12 are then inserted into the housing 14 through the fitting holes 116.
Subsequently, with the tip portions 12A of the tracing member 12 inserted in the housing 14, the rear end portion 12B of the tracing member 12 is moved toward the guide holes 118 (see FIG. 11).
After the rear end portion 12B of the tracing member 12 has been moved to the guide holes 118, while the tip portions 12A of the tracing member 12 are being inserted into tapered guide portions 160 of the circulatory cam grooves 30, 148 while being guided by the guide plate 120, the rear end portion 12B is pushed into the fitting grooves 122, thereby completing the assembling operation (see FIG. 12).
It should be noted that the pushing in of the rear end portion 12B of the tracing member 12 can be facilitated if an appropriate pushing-in tool such as a screwdriver is used.
A description will now be given of a second embodiment of the second aspect of the invention.
As shown in FIG. 13, the present invention is applicable to a structure in which a circulatory cam groove having a stepped portion is formed on only one surface of the latch body, as in the case of a conventional latch device.
That is, if the arrangement provided is such that the rear end portion 12B of the tracing member 12 is fitted by being received in the pair of fitting grooves 122, a fixing member for fitting the tracing member 12 is not required separately.
A description will now be given of a first embodiment of a third aspect of the invention.
FIGS. 15 and 16 illustrate a lock mechanism 210 which is applied to a push-open type ash pan in accordance with the first embodiment of the third aspect of the invention.
This lock mechanism comprises a tracing member 214 fitted on an insertion-side rear surface 212A of an ash pan case 212 (see FIG. 16) as well as a pair of circulatory cam grooves 30, 148 respectively formed on both sides of a circulatory-cam-groove fitting member 218 provided on the right-hand side of a box 216 as viewed in the drawing. The tracing member 214 is disposed on the rear surface 212A of the ash pan case 212 at a position corresponding to the circulatory-cam-grooves 30, 148. When a front surface 212B of the ash pan case 212 is pushed in the direction of arrow G, the tracing member 214 is adapted to be inserted into the pair of circulatory-cam-grooves 30, 148.
The tracing member 214 has a substantially C-shaped configuration formed by cutting off a portion of a ring. Opposite end portions of the tracing member 214 are formed as tracing portions 224, 226. The gap t between the ends of the tracing portions 224, 226 is set to be greater than the distance between the bottom surfaces of the circulatory cam grooves 30, 148. The arrangement provided is such that when the tracing portions 224, 226 of the tracing member 214 are inserted into the circulatory-cam-grooves 30, 148, the tracing member 214 moves in a circulating manner with the ends of the tracing portions 224, 226 not being brought into contact with the bottom surfaces of the circulatory cam grooves 30, 148, but with the tracing portions 224, 226 being brought into contact with the wall surfaces of the circulatory-cam-grooves 30, 148.
The tracing member 214 is supported on the rear surface 212A of the ash pan case 212 in such a manner as to be twistable in the direction of the double-headed arrow S (see FIG. 15), but retaining portions 228, 230 respectively formed in upper and lower portions of a fixing member 213 restrict the twisting motions of the tracing portions 224, 226 in the mutually closing direction.
The circulatory-cam-grooves 30, 148, which are respectively formed in the upper and lower surfaces of the circulatory-can-groove fitting member 218, are provided with mutually different configurations.
The circulatory-cam-groove 30 shown by the solid lines has a configuration in which an upwardly projecting heart-shaped cam 232 is left uncut in a substantially central portion of the upper portion of the circulatory-cam-groove fitting member 218. A widthwise extending groove wall surface 234 is provided on the side of the circulatory-cam-groove fitting member 218 which is the insertion-end side of the tracing member 214, and a projection 238 is formed in a central portion thereof in such a manner as to project toward a recessed portion 236 of the heart-shaped cam 232.
Meanwhile, a heart-shaped cam 240, a groove wall surface 242, and a projection 244 are formed on the circulatory-cam-groove 148 shown by the broken lines in the same way as the circulatory-cam-groove 30 but with different configurations. The tracing portion 224 circulating in the circulatory-cam-groove 30 and the tracing portion 226 circulating in the circulatory-cam-groove 148 are arranged to be spaced apart from each other by being pressed by the groove wall surfaces.
The recessed portion 236 disposed on the circulatory cam groove 30 is located at a position slightly offset in the direction of arrow G from a recessed portion 246 as seen in a plan view. This arrangement is provided to ensure that, in view of the tolerances of the tracing portions 224, 226, either one of the combinations of the tracing portion 224 and the recessed portion 236 on the one hand, and the tracing portion 226 and the recessed portion 246 on the other, is made to engage earlier than the other so as to positively lock the tracing member 214. It should be noted that since the tracing member 214 is extended by the urging force of the unillustrated compression coil, the offset of the recessed portions 236, 246 is canceled, so that the engaged tracing member 214 is supported at two points, i.e., the recessed portions 236, 246 (see FIG. 21).
In addition, although groove wall surfaces 248, 250 are formed on both sides of the circulatory cam groove 148 in an insertion direction of the tracing member 214, groove wall surfaces are not formed on the circulatory-cam-groove 30. The reason for this is that the tracing portion 224 is pressed against the wall surface of the heart-shaped cam 30 by the twisting force or torsion of the tracing member 214 and therefore does not move outside the circulatory cam groove 30. Even if the tracing portion 224 moves away from the heart-shaped cam 30, the tracing portion 224 is guided into an insertion portion 252 of the circulatory cam groove 30 by following the tracing portion 226 by virtue of the restoring force due to the twisting of the tracing member 214. Hence, it is unnecessary to form a groove wall surface for guiding the tracing portion 224 on the circulatory cam groove 30.
It should be noted that an insertion portion 252 of the circulatory-cam-groove fitting member 218 for the insertion of the tracing member 214 into the circulatory-cam-grooves 30, 248 is machined into a tapered configuration, so as to facilitate the tracing member 214.
The operation of this embodiment will now be described with reference to FIGS. 16 to 25.
In the state shown in FIG. 16, if the front surface 212B of the ash pan case 212 is pressed in the direction of arrow G, the tracing portions 224, 226 of the tracing member 214 fixed to the rear surface of the ash pan case 212 are respectively inserted into the circulatory-cam-grooves 30, 148 formed in both surfaces of the circulatory-cam-groove fitting member 218 fixed to the box 216 (FIG. 17).
Furthermore, if the front surface 212B of the ash pan case 212 is pressed further in the direction of arrow G, the tracing portion 226 of the tracing member 214 is guided along the wall surface 250 of the circulatory-cam-groove 148. Meanwhile, since no groove wall surface is formed on the insertion portion 252 of the circulatory cam groove 30, the tracing portion 224 moves by following the tracing portion 226.
Then, as shown in FIG. 18, if the front surface 212B of the ash pan case 212 is pressed still further in the direction of arrow G, the tracing portion 226 moves in the direction of arrow J while being guided by the groove wall surface 250. Meanwhile, since the tracing portion 224 moves in the direction of arrow 1 while being guided by a heart-shaped cam 232A, the tracing portion 224 is gradually offset in the direction in which the tracing portions 224 and 226 are spaced apart from each other, so that a twisting force is produced in the tracing member 214.
Then, as shown in FIG. 19, when the tracing portion 224 reaches an angular portion 232B of the hear-shaped cam 232, the offset between the tracing portions 224 and 226 becomes maximum, and the twisting force becomes maximum.
Then, in the state shown in FIG. 19, if the front surface 212B of the ash pan case 212 is pressed still further in the direction of arrow G, the tracing portion 224 moves in the direction of arrow J by riding over the angular portion 232B of the heart-shaped cam 232 by virtue of the torsion-restoring force. Then, the tracing portion 224 collides against a projection 238A of the groove wall surface 234 and clicks, and at the same time its positional offset with respect to the tracing portion 226 is canceled.
Subsequently, as shown in FIGS. 20 to 21, when an overstroke portion of the pressing operation is overcome by the urging force of the unillustrated compression coil spring, the tracing member 214 moves in the direction of arrow H. At this juncture, the tracing portion 224 is guided by a wall surface 232C of the heart-shaped cam 232, while the tracing portion 226 is guided by a projecting portion 244A of the projection 244 of the circulatory cam groove 148. That is, since the tracing portions 224 and 226 are respectively pressed in the direction of arrow J and in the direction of arrow I, torsion is produced in the tracing member 214. At this juncture, if the tracing member 214 moves further in the direction of arrow H, the tracing portion 226 is disengaged from the projecting portion 244A of the groove wall surface, and its positional offset with respect to the tracing portion 224 is canceled by means of the restoring force. Consequently, the tracing portions 224, 226 whose positional offset has been canceled are guided by the wall surface 232C, and are retained at the recessed portions 236, 246.
At this juncture, since the prevention of the pulling out of the tracing member 214 is effected at two positions, i.e., the recessed portions 236, 246 on both surfaces of the circulatory-cam-groove fitting member 218, the tracing member 214 can be locked firmly.
Then, if the front surface 212B of the ash pan case 212 with the tracing member 214 in the locked state is pressed again, the tracing portion 226 and the tracing portion 224 move in the direction of arrow J while the former is being guided by a wall surface 240A of the heart-shaped cam 240 and the latter is being guided by a projection 238B of the groove wall surface. As a result, torsion is produced again in the tracing member 214. It should be noted that since the recessed portions 236, 246 are formed in such a manner as to be offset in the direction of arrow J from the tip of the projecting portion 244A on the groove wall surface, when the tracing member 214 is pressed again and an overstroke is created, the tracing portions 224, 226 are prevented from circulating in an opposite direction.
Then, if the front surface 212B of the ash pan case 212 with the tracing member 214 in the locked state is pressed further in the direction of arrow G, the tracing portion 226 rides over the tip of the wall surface 240A by means of the restoring force of the tracing member 214, cancels the positional offset with respect to the tracing portion 224, and assumes the state shown in FIG. 23.
In the state shown in FIG. 23, the overstroke of the tracing member 214 becomes maximum, and if the pressing in the direction of arrow G is canceled, the tracing member 214 is pushed back in the direction of arrow H by the urging force of the unillustrated compression coil spring. However, the tracing portion 226 is interfered by an annular portion 240B of the heart-shaped cam 240, so that it cannot move in the opposite direction to the circulating direction.
Furthermore, when the compression coil spring pushes back the tracing member 214 in the direction of arrow H as shown in FIG. 24, the tracing member 214 moves in the direction of arrow H with the tracing portions 224, 226 being guided by a wall surface 232D of the heart-shaped cam 232 and the wall surface 248 of the circulatory-cam-groove 30.
Then, as shown in FIG. 25, as the withdrawal of the tracing member 214 advances further, the tracing portion 226 moves in the direction of arrow I while being guided by the wall surface 248 of the circulatory-cam-groove 148. Meanwhile, since the tracing portion 224 moves in the direction of arrow J while being guided by a wall surface 232E of the heart-shaped cam 232, the positions of the tracing portions 224 and 226 are offset, whereupon a twisting force is produced again in the tracing member 214.
When the tracing portion 224 reaches a tip 232F of the heart-shaped cam 232, the positional offset between the tracing portions 224 and 226 becomes maximum, and the twisting force becomes maximum.
At this juncture, if the tracing portion 214 moves further in the direction of arrow H by being pushed back by the compression coil spring, at the same time as the tracing portion 224 leaves the tip 232F of the heart-shaped cam 232, the positional offset between the tracing portions 224 and 226 is canceled by means of the restoring force due to the twisting of the tracing member 214. When the tracing member 214 is further pulled back by the compression coil spring, the tracing member 214 leaves the circulatory-cam-grooves 30, 148, and the ash pan case 212 is pulled out of the box 216 (see FIG. 16).
It should be noted that although in the above-described embodiment a description has been given of a case in which the lock mechanism in accordance with the present invention is applied to a push-open type ash pan, the present invention is not restricted to the same. For instance, the lock mechanism in accordance with the present invention may be used as a means for locking an openable cover.
A description will now be given of a second embodiment of the third aspect of the present invention.
The first embodiment of the third aspect makes use of the resilient restoring force (torsion) of the tracing member 214 acting perpendicularly to the axis of the tracing member 214. In contrast, as shown in FIG. 26, this embodiment makes use of the resilient restoring force of a tracing member 260 acting parallel with the axis of a tracing member 260 so as to cause the tracing member 260 to circulate in a fixed direction.
That is, the circulatory-cam-grooves 30, 148 described in the first embodiment of the third aspect of the invention are provided on one surface of a circulatory-cam-groove fitting member 264, and a restoring force in a bending direction is produced in the tracing member 260 by positional offset in the direction of arrow P between tracing portions 266, 268 moving in a circulating manner after being inserted into the circulatory-cam-grooves 30, 148 in the direction of arrow N. By virtue of this restoring force in the bending direction, the tracing member 260 is circulated in a fixed direction.
According to this arrangement, since it is unnecessary to provide the circulatory-cam-grooves 30, 148 on both surfaces of the circulatory-cam-groove fitting member 264, the lock mechanism 258 can be made thin.
A description will now be given of a fourth aspect of the present invention.
FIG. 27 shows a latch device L to which the lock mechanism 210 in accordance with the present invention is applied.
Since the external configurations of the latch body 210 and the housing 214 and the structure of the compression coil spring 24 are the same as those described in the embodiment of the first aspect of the invention. Therefore, these component parts and their portions will be denoted by the same reference numerals, and a description thereof will be omitted here.
The recessed portion 28 is formed on each of the top surface 226 and the unillustrated bottom surface of the latch body 10. The circulatory-cam-grooves 30, 148 described in the first embodiment of the third aspect are formed on the recessed portions 28, respectively, and the tracing portions 224, 226 of the tracing member 214 are inserted into the circulatory-cam-grooves 30, 148, and move in a circulating manner in the circulatory-cam-grooves 30, 148 while being brought into contact with the wall surfaces of the circulatory-cam-grooves. It should be noted that in this embodiment the wall surface 248 provided on the circulatory-cam-groove 148 described in the first embodiment of the third aspect of the invention is not provided, and is substituted by an inner wall 14A of the housing 14 so as to make the latch device compact.
The portion of the tracing member 214 remote from the tracing portions 224, 226 is twistably fixed on the inner wall of the housing 14.
As shown in FIG. 28, the projection 32 is formed on the top surface of the latch body 10, and is fitted in the elongated guide hole 31 formed in the housing 14. As a result, as the projection 32 moves in the elongated guide hole 31, the latch body 10 is moved reciprocatively relative to the housing 14. Also, as the projection 32 is brought into contact with one end of the elongated guide hole 31, further movement of the latch body 10 in the direction in which it is pulled out is prevented against the urging force of the compression coil spring 24.
As shown in FIG. 27, the pair of arms 36 are provided on the side of the latch body 10 which is remote from the insertion side of the housing 14, and their distal ends are spaced apart from each other. The enlarged-diameter end portion 34B of the striker 34 secured to an unillustrated openable cover is inserted between the arms 36 to press the central portion 10A of the arms 36, so as to push the latch body 10 into the housing 14.
The operation of this embodiment will be described hereinunder.
Before the latch body 10 is pressed by the enlarged-diameter end portion 34B of the striker 34 (see FIG. 27), the projection 32 formed on the latch body 10 is retained at one end of the elongated guide hole 31 (see Fig. 28), so that the latch body 10 is prevented from being pulled out. At this juncture, as shown in FIG. 27, the arms 36 are in an open state, and the tracing portions 224, 226 of the tracing member 214 are at a tip portion 237 of the latch body 10.
In the state shown in FIG. 29, if the central portion 10A of the arms 36 is pressed by the striker 34 to push the latch body 10 into the housing 14, the outer sides of the arms 36 are brought into contact with the rectangular frame 16, and the arms 36 rotate in the mutually approaching direction with the hinges 36B. As a result, the enlarged-diameter end portion 34B of the striker are held by the arms 36, thereby closing the openable cover.
At this juncture, the tracing portions 224, 226 of the tracing member 214 are guided along the groove wall surfaces of the circulatory-cam-grooves 30, 148, engage the recessed portions 236, 246, respectively, thereby preventing the latch body 10 from coming off.
It should be noted that since the operation and effect of the tracing member 214 relative to the circulatory cam grooves 30, 148, are the same as those of the first embodiment of the third aspect of the invention, a description thereof will be omitted.
Although in this embodiment stepped portions are not provided on the circulatory cam grooves 30, 148, it is possible to provide each surface of the latch body 10 with a circulatory-cam-groove having conventional stepped portions, and to allow the tracing member 214 of this embodiment to trace the grooves. However, in order to make the latch device compact, it is preferable not to provide the circulatory-cam-groove with stepped portions.
In addition, although in this embodiment the side surface portions of the distal ends of the tracing member 214 are formed as the tracing portions, if the circulatory cam grooves are formed of a hard material, the circulatory cam grooves may be traced by the end faces of the tracing member 214.
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A lock mechanism for causing an openable member such as a cover or a door of a box or the like to engage with or disengage from a main body as the openable member is pressed, and a latch device for retaining a latch body in the housing in a state in a pushed-in state and in a withdrawn state. The center of rotation of each of a pair of arms of the latch device is formed on substantially the same line as a line of action of a force acting on a retaining surface of each of the arms for retaining a striker. A fitting hole, a guide hole, a slanted guide surface, and a fitting hole are provided to allow a tracing member of the latch device to be fitted from outside the housing at the time of assembling the tracing member to the housing. In the lock mechanism and the latch device, the tracing member is caused to trace side walls of a pair of circulatory guide paths by making use of the resilient restoring force of a resilient tracing member, and the tracing member is maintained in a state of noncontact with bottom surfaces of the circulatory guide paths during tracing.
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TECHNICAL FIELD
This invention relates in general to communication systems and more specifically to a method for automatically assigning encryption information to a group of radios.
BACKGROUND
Present day communication systems allow for reprogramming of radio encryption information (also known as "encryption keys" or "keys") using a central encryption station which transmits encryption information to remote radios which are part of the communication system using radio frequency (RF) signals. This over-the-air transmission of encryption information requires a computer data base to be kept in order to keep track of which encryption keys have been assigned to which radios in the system.
Although over-the-air (OTAR) encryption systems are well known in the art, some brief definitions of some common terms used in the art are given below:
traffic encryption key: A key used to encrypt and decrypt voice messages.
common shadow key: A key used to encrypt the traffic keys that a sent to subscribers.
talk group: A user-defined group of subscribers that need to be able to communicate. Subscribers in a talk group will have one traffic encryption key in common between all of the subscribers in the group.
rekey group: A group of subscribers that belong to the same combination of talk groups. The subscribers in a rekey group will have the same set of traffic keys and will also share a common shadow key. These groups are transparent to the user.
Referring to FIG. 1, there is shown a block diagram of a prior art trunked radio communication system 100 in accordance with the invention. Radio communication system 100 includes a plurality of communication devices 200 such as two-way subscriber radios, mobile radios, fixed stations, etc. A controller interface 102 (such as a Digital Interface Unit manufactured by Motorola, Inc.) is included as part of the system and provides encryption functions and interface to a set of communication channel resource, such as repeater 106. The controller interface 102 also provides access between the communication channel resources 106 and the Key Management Controller (KMC) 104 and/or a manned control console such as a central controller 110 which may be utilized to coordinate the system's communication activity.
Control console 110 includes a speaker and other audio switching hardware for monitoring the received messages from repeaters 106 and a transmission means which includes a microphone and audio routing circuitry for transmitting messages to the communication devices 200. Control signals originating at control console 104 are transmitted via a dedicated control channel 108 to radios 200 which monitor the control channel for control information on a routine basis. Control console 110 is in charge of assigning voice/data repeaters 106 to groups of radios 200. Control console 110 also sends control signals to radios 200 which automatically direct groups of radios 200 to appropriate repeaters 106.
The controller interface 102 provides the encryption function for both voice/data and other types of information messages during both transmit and receive operations. Although FIG. 1 is shown as a trenched system, the present invention can also be used in cellular and other types of communication systems. Repeaters 106 which are connected to the controller interface 102 each comprise a transmitter and receiver section for use in communicating with communication devices 200.
Coupled to controller interface 102 is an encryption key management controller 104 such as a Key Management Controller (KMC) manufactured by Motorola, Inc. KMC 104 is a computerized system which includes a database means such as a computerized database of all system users, as well as encryption key information for all communication devices. KMC 104 also includes control software for determining which units have been rekeyed and which have not. KMC 104 decides when to poll each of the communication devices 200 in order to reprogram their encryption information after the system administrator decides to change the communication device's encryption keys. KMC 104 can be programmed to automatically update the communication device's encryption keys.
KMC 104 establishes communication with the communication units 200 via control channel 108 which is another repeater which allows the KMC bi-directional communication capability with the communication devices 200. Although shown as separate units, controller interface 102 and KMC 104 could be combined to form an integrated system controller. Furthermore, the KMC 104 and controller interface 102 may be utilized without the presence of a manned audio control console 108 in systems where audio is not required at the KMC location.
The KMC 104 also sets up mappings of encryption keys describing what keys should be loaded into which particular radios. These maps are then assigned to a rekey group and individual radios users are then assigned to the rekey groups. Presently, the procedure for assigning a group of radio subscribers their own traffic encryption key requires the steps of first, removing the subscribers from their current rekey groups. Next, a new rekey group is created for every rekey group that has a subscriber that will be in the new rekey group. A new map is then created with the appropriate traffic encryption keys for each new rekey group. Finally, the subscribers are added to their new rekey groups.
In FIG. 2, a block diagram of the functions performed by prior art KMC 104 are shown. In order to assign a group of radios their own traffic encryption key using this KMC configuration the radio users are first removed from their current rekey groups. Next, a new rekey group must be created for every rekey group that has a subscriber that will be in the new group. A new map must then be created with the appropriate traffic encryption keys for each new rekey group. Finally, the radio must be added to their new rekey groups.
In the prior art KMC, blocks 206 and 212 are the only functions which can be accomplished automatically by the KMC without the need for user involvement.
The problem with the above process is that keeping track of rekey groups and maps can become cumbersome as the communication system becomes larger (i.e., more radio subscribers are added to the system). Given this problem, their exists in the art a need for a method and apparatus for automatically mapping encryption information to radios.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a prior art radio communication system in accordance with the invention.
FIG. 2 is a block diagram of a prior art encryption key management controller configuration.
FIG. 3 is a block diagram of encryption key management controller with automatic key mapping in accordance with the invention.
FIG. 4 shows a flowchart describing the steps for adding a radio unit to an existing radio talk group in accordance with the invention.
FIG. 5 shows a flowchart describing the steps for deleting a radio from an existing radio talk group in accordance with the invention.
FIG. 6 shows a flowchart describing the steps for adding a radio talk group to the communication system in accordance with the present invention.
FIG. 7 shows a flowchart describing the steps for deleting a radio talk group from a communication system in accordance with the present invention.
FIG. 8 shows an example of a set of radio talk groups.
FIG. 9 shows an example of a set of rekey groups.
FIG. 10 shows how the radio talk groups of FIG. 8 are mapped to the rekey groups of FIG. 9 and then to the individual radios.
FIG. 11 shows the condition of the rekey groups after the illustrative examples have occurred.
FIG. 12 shows the mapping of radio talk groups to rekey groups to individual subscriber units after performing the illustrative examples in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.
Referring now to FIG. 3, a block diagram of a KMC configuration providing for automatic key mapping in accordance with the present invention is shown. In the present invention, the generation of new rekey groups and maps (blocks 302 and 310) is handled automatically by the system instead of the user as shown in FIG. 2, thereby greatly simplifying the work needed to change the subscriber groupings.
The purpose of the automatic encryption key mapping algorithm of the present invention is to automate the mapping or linking of traffic keys to subscriber radio units using a unique algorithm. The system user need only specify which units should be able to communicate with one another. The maintenance of the keys and the mapping of those keys to the correct subscribers is automated. As far as the user is concerned, there are no `rekey groups`. All subscribers are placed into `talk groups` where all subscribers in a particular talk group share a common traffic encryption key. System users only need to generate new talk groups and add subscribers to the talk groups. A particular subscriber may belong to multiple radio talk groups. In accordance with the invention, rekey groups are automatically generated and maintained based on the talk groups.
The operations that are allowed on the radio talk groups and the steps taken by the present invention in different system situations are discussed below.
Subscriber radio unit is added to an existing talk group:
In order to add a radio unit to an existing radio talk group, the subscriber unit is first deleted from its original rekey group as shown in step 402, in FIG. 4. If it is determined in step 404 that the subscriber's original rekey group is empty (no radios assigned to that particular rekey group), then the rekey group is deleted in step 404. Next, in step 406, the new radio talk group is added to the list of the subscriber's talk groups. If a rekey group exists with the same combination of talk groups as this subscriber in decision block 408, the present invention adds the subscriber to the rekey group in step 410, otherwise, a new rekey group with a unique common shadow key is created in step 412. Finally, a mapping between the rekey group and all of the subscriber's talk groups is added in step 414.
Subscriber radio is deleted from an existing talk group:
A subscriber radio may only be deleted from a talk group if it belongs to at least one other talk group since every subscriber radio in the communication system must belong to a least one radio talk group. In FIG. 5, the steps required to delete a subscriber unit from an existing talk group are shown. In step 502, the subscriber radio is deleted from its original rekey group. Next, in step 504, it is determined if the subscriber's original rekey group is empty, and if empty, that rekey group is deleted. In step 506, the old radio talk group is deleted from the list of the subscriber's talk groups. If a rekey group exists with the same combination of talk groups as this subscriber in step 508, the subscriber radio is added to the rekey group in step 510.
If in step 508, a rekey group does not exist with the same combination of talk groups as the subscriber unit in step 512, a new rekey group with a unique common shadow key is created. Finally, in step 514, an automatic mapping (linking) between this rekey group and all of the subscriber's talk groups is done.
A radio talk group is added:
In FIG. 6, the steps needed to add a new radio talk group to the communication system in accordance with the preferred embodiment of the invention are shown. The first step, as outlined in step 602, is to create a unique traffic key for the new radio talk group. Once this is accomplished, the routine outlined in FIG. 4 is followed in step 604 for each subscriber that is to be in the new radio talk group.
A radio talk group is deleted:
Referring to FIG. 7, the steps required to delete a radio talk group in accordance with the present invention are shown. Please note that a radio talk group may only be deleted if there are no subscribers whose only talk group is the talk group which is being deleted, since every subscriber radio in the communication system must belong to at least one radio talk group. In step 702, it is determined if the above condition is met. In step 704, for each subscriber radio in the talk group to be deleted, the steps outlined in the flowchart of FIG. 5 is followed for deleting a subscriber from a talk group. Finally, in step 706, the talk group and all of its corresponding mappings are deleted.
Illustrative examples:
In order to better illustrate the above mentioned features, a few illustrative examples will now be discussed with reference to FIGS. 8-10. FIG. 8 shows a set of radio talk groups designated as radio groups "A", "B", "C" and "D" are shown. Eight radios (1-8) are assigned to the four radio talk groups as shown. In FIG. 9, the same radio subscribers (1-8) are shown with their corresponding rekey groups. In FIG. 10, the radio talk group to rekey group and rekey group to individual radio subscriber mappings in accordance with the preferred embodiment of the invention are shown.
Illustrative example 1:
In accordance with the invention in order to add subscriber radio number 4 to radio talk group "B" the following steps are taken:
Step 1. First, subscriber radio number 4 is deleted from rekey group "RG7";
Step 2. Since RG7 is now empty, the entire rekey group RG7 is deleted;
Step 3. Next, radio talk group B is added to the list of talk groups for subscriber radio 4;
Step 4. Subscriber 4 now has A, B, and D as its talk groups;
Step 5. Compare the talk group combination of subscriber radio 4 with the current rekey groups.
Step 6. Subscriber 4 now has the same combination of talk groups as rekey group "RG4", so subscriber 4 is added to rekey group RG4.
Illustrative example 2
In order to delete subscriber radio 7 from talk group "D" the following steps are taken:
Step 1. Subscriber radio 7 is deleted from rekey group RG5;
Step 2. Radio talk group "D" is removed from the list of radio talk groups for subscriber 7. Subscriber radio 7 now has A, B, and C, as its radio talk groups;
Step 3. Next, the radio talk group combination of subscriber 7 with the current rekey groups are compared;
Step 4. Since no rekey group exists for the combination of talk groups A, B, and C, a new rekey group RG8 is generated, with a unique common shadow key; and
Step 5. Finally, subscriber 7 is added to rekey group RG8.
Referring to FIGS. 11 and 12, the radio talk group to rekey group and rekey group to radio subscriber mappings are shown in accordance with the preferred embodiment of the invention after illustrative examples 1 and 2 above were performed.
Adding and deleting talk groups are an extension of the steps discussed above, with the additional step of a creating traffic encryption key when a talk group is created (as discussed with reference to FIGS. 6 and 7). While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.
In summary, automatic key mapping in accordance with the present invention greatly simplifies the process of assigning encryption keys to individual radios in a communication system. By automatically mapping traffic encryption keys to radio subscribers the time required to fully define an encrypted system is shortened, thereby simplifying the task for communication system users.
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This invention provides for a method for automatically assigning encryption keys to radios in a communication system. The radio users need only specify which radio units should be able to communicate with each other. The system takes care of automatically mapping traffic keys to subscribers in order to accomplish the desired radio groupings, thereby simplifying the process of assigning encryption information in a communication system.
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BACKGROUND OF THE INVENTION
Standard microelectromechanical systems (MEMS) processing techniques create structures that are symmetric in the z axis (out of the wafer's surface) but can vary in the x and y axes (in the plane of the wafer's surface). This leads to devices which can only move in the x/y plane. Presently, creating asymmetry in the z-axis can be performed by deflecting with stiction plates or by selective thinning. Deflecting with stiction plates leads to devices which are sensitive to z motion, but is not easily implemented for multiple z-offsets in both directions and also requires more steps and additional processing layers, thereby costing more money. Selective thinning is performed by thinning one set of teeth in the Z-direction, but this requires an extra mask and additional etches, and it is also rather inaccurate.
Thus, there exists a need for methods to easily form z-offsets in MEMS devices.
BRIEF SUMMARY OF THE INVENTION
A microelectromechanical system (MEMS) device with a mechanism layer having a first part and a second part, and at least one cover for sealing the mechanism layer. The inner surface of at least one of the covers is structured such that a protruding structure is present on the inner surface of the cover and wherein the protruding structure mechanically causes the first part to be deflected out of a plane associated with the second part.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A , 1 B, and 1 C illustrate a cross-sectional side view before assembly, a cross-sectional side view after assembly, and a cross-sectional top view of a microelectromechanical system (MEMS) comb structure device in accordance with one embodiment of the invention;
FIGS. 2A , 2 B, and 2 C illustrate a cross-sectional side view before assembly, a cross-sectional side view after assembly, and a cross-sectional top view of an alternative embodiment of the invention; and
FIG. 3 illustrates a cross-sectional top view of an additional embodiment of the invention.
FIG. 4 illustrates a schematic view of a system including one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1A , 1 B and 1 C illustrate a side view before assembly, a side view after assembly and a top view of a microelectromechanical system (MEMS) comb structure device 30 formed in accordance with one embodiment of the invention. FIGS. 1A and 1B show that the device 30 has a top cover 4 and a bottom cover 5 enclosing a mechanism layer 32 that includes a first side 10 , a second side 12 directly opposite the first side 10 , a movable part 14 , a first fixed part 16 , a second fixed part 18 , and flexures 20 . Flexures may also be referred to as torsional flexures or as hinges. FIG. 1A illustrates a cross-sectional side view of the comb structure device 30 shown in FIG. 1B before the top cover 4 and the bottom cover 5 have been attached to the device 30 . For purposes of FIGS. 1B and 1C , the positive z direction is defined to run from the bottom cover 5 to the top cover 4 such that it is orthogonal to the outer surfaces of both of the covers and orthogonal to the mechanism layer. The top cover 4 has a structure 6 protruding from its inner surface that causes the second fixed part 18 to be mechanically deflected in the negative z direction and away from the plane associated with the movable part 14 when the top cover 4 is attached to the first side 10 and the second side 12 . Bottom cover 5 has a structure 8 protruding from its inner surface that causes the first fixed part 16 to be mechanically deflected in the positive z direction and away from the plane associated with the movable part 14 when the bottom cover 5 is attached to the first side 10 and the second side 12 .
Cross-sectional top view FIG. 1C shows that the mechanism layer also has a third side 40 and a fourth side 42 so that the movable part 14 , the first fixed part 16 , and the second fixed part 18 are surrounded on four sides by the first side 10 , the second side 12 , the third side 40 , and the fourth side 42 . The movable part 14 is held in place by hinges 24 and 26 attached to the third side 40 and the fourth side 42 which allow the movable part 14 to rotate about the hinges 24 and 26 but keep the movable part relatively fixed with respect to translational movement in the x/y plane. FIG. 1C also illustrates that the movable part 14 is formed such that a series of comb electrodes protrude towards the first fixed part 16 and the second fixed part 18 . The first fixed part 16 and the second fixed part 18 include a series of comb electrodes protruding from the side facing the movable part 14 . The comb electrodes of the first fixed part 16 and the second fixed part 18 are interleaved with the comb electrodes protruding from the sides of the movable part 14 . In another embodiment, a non-sealed device may be formed without using the first side 10 , the second side 12 , the third side 40 , and the fourth side 42 . An alternative embodiment based on the non-sealed device could also be formed, where flexures 20 are temporary structures that are put in a dicing space between each comb structure device 30 , and removed in a final configuration. In some embodiments, structure 6 will be bonded to the second fixed part 18 and structure 8 will be bonded to the first fixed part 16 .
FIGS. 2A , 2 B, and 2 C illustrate a cross-sectional side view before assembly, a cross-sectional side view after assembly, and a cross-sectional top view of an alternative embodiment of the invention. FIGS. 2A and 2B show that a device 80 has a top cover 100 and a bottom cover 102 enclosing a mechanism layer 120 that includes a first side 106 , a second side 108 directly opposite the first side 106 , a movable part 110 , a fixed part 112 , and flexure 20 . FIG. 2A illustrates a cross-sectional side view of the comb structure device 80 shown in FIG. 2B before the top cover 100 and the bottom cover 102 have been attached to the device 80 . For purposes of FIGS. 2B and 2C , the positive z direction is defined to run from the bottom cover 102 to the top cover 100 such that it is orthogonal to the outer surfaces of both of the covers and the mechanism layer 120 . The top cover 100 has a structure 104 protruding from its inner surface that causes the fixed part 112 to be mechanically deflected in the negative z direction and away from the plane associated with the movable part 110 when the top cover 100 is attached to the first side 106 and the second side 108 . Bottom cover 102 is attached to the first side 106 and the second side 108 .
Cross-sectional top view FIG. 2C shows that the mechanism layer also has a third side 130 and a fourth side 132 so that the movable part 110 and the fixed part 112 are surrounded on four sides by the first side 106 , the second side 108 , the third side 130 , and the fourth side 132 . The movable part 110 is held in place by hinges 134 and 136 attached to the third side 130 and the fourth side 132 which allow the movable part 110 to rotate about the hinges but keep the movable part relatively fixed with respect to translational movement in the x-y plane. FIG. 2C also illustrates that the movable part 110 is formed such that a series of comb electrodes protrude on the side facing the interior of the device. The fixed part 112 is also shown to each have a series of comb electrodes protruding from the side facing the movable part 110 . The comb electrodes of the fixed part 112 are interleaved with the comb electrodes protruding from the side of the movable part 110 .
FIG. 3 illustrates a cross-sectional top view of a device 150 that is an additional embodiment of the invention. In this embodiment, more than two parts are deflected. Three fixed parts 152 are deflected up and three fixed parts 154 are deflected down relative to a central comb part 156 .
FIG. 4 illustrates a schematic view of a system 190 including one embodiment of the present invention. A comb structure accelerometer 200 such as that described in FIGS. 1B and 1C in signal communication with rebalance electronics 202 . The rebalance electronics 202 rebalances the comb structure accelerometer 200 . Sense electronics 204 , receives signals from the comb structure accelerometer 200 and produces a relevant output signal 206 to be used in further processing or storage. The signal 206 can be fed back into the rebalance electronics 202 , if closed loop operation is desired.
The structures 6 , 8 , and 104 protruding from the inner surfaces of the covers 4 , 5 , and 100 and the covers 4 , 5 , and 100 themselves may be formed of a monolithic material such as silicon or pyrex, for example, or the structures 6 , 8 , and 104 may be attached or deposited on the surface of each cover in alternative embodiments. If structures 6 , 8 , or 104 are attached or deposited on the surface of covers 4 , 5 , or 100 , structures 6 , 8 , or 104 may be made of the same material such as silicon or pyrex, for example, or a different material such as a metal, for example, as covers 4 , 5 , and 100 . Also, for example, the structures 6 , 8 , and 104 protruding from the inner surfaces of the covers 4 , 5 , and 100 could be used to deflect the movable parts 14 and 110 of the devices 30 and 80 instead of or in addition to deflecting the fixed parts 16 , 18 , and 112 .
While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Additionally, the MEMS device itself may be a sensor or an actuator acting as a sense mechanism or a drive mechanism. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.
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A microelectromechanical system (MEMS) device with a mechanism layer having a first part and a second part, and at least one cover for sealing the mechanism layer. The inner surface of at least one of the covers is structured such that a protruding structure is present on the inner surface of the cover and wherein the protruding structure mechanically causes the first part to be deflected out of a plane associated with the second part.
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FIELD OF THE INVENTION
The instant invention relates to pressure balanced valves which minimize the valve actuating force regardless of the fluid pressure in the system in which the valves are installed.
BRIEF DESCRIPTION OF THE PRIOR ART
Many different varieties of valves have been developed over the years, among them a gate valve, in which a generally planar valve element moves perpendicularly to the fluid flow direction, a ball valve in which a ball-shaped element having a passage therethrough is rotated about an axis oriented generally perpendicularly to the fluid flow, and a check valve in which a valve element is biased against a valve seat by a spring force. Although generally these type of valves have worked exceedingly well over the years, problems have arisen with their operation when they are used in high pressure fluid systems. The large pressure differential across the valve when the valve element is closed requires a large external force to move the valve elements to their open position. For example, a 1000 psi differential pressure across a gate or ball valve with a circular sealing area of two inches diameter exerts a force of 3140 pounds against the valve seal. The external force required to open valves under these conditions is excessive, even when mechanical systems, such as worm gear drives, are incorporated into the valve structure.
The aforementioned problems become even more crucial when the valve is used in a remote location, such as a down-hole well environment. It is often necessary to seal off a well, such as a high pressure gas well, at some point along its length in order to hydrotest the well tubing to locate leaks, or to perform other routine maintenance. The extremely high pressures associated with gas wells (on the order of 2400 psi) makes the operation of standard gate and ball valves an exceedingly difficult and time consuming proposition and, in the extreme cases, renders their usage virtually impossible. Quite obviously, it is in the economic interest of the well operator to minimize the down-time required to hydrotest the tubing or perform other routine maintenance. Any valve structure which would minimize this time would be of great economic benefit to the industry.
SUMMARY OF THE INVENTION
The instant invention provides a pressure balanced type valve which requires minimal actuating force to open and close the valve, regardless of the pressure differential across the valve. The configuration of the valve stem in combination with a pressure relief port on the valve stem seat relieves any differential pressure. In the absence of differential pressure, the valve stem is not forced in any direction, as the resultant of the forces acting on the cross-sectional areas of the valve stem is zero. In its broadest configuration, the valve has an enlarged area on either end of the stem and is located such that, when the valve is in the closed position, one of the enlarged areas blocks the fluid flow passage. The longitudinal axis of the valve stem is oriented such that it moves generally perpendicular to the fluid flow path. Since the enlarged portions are of equal area, the fluid bearing against these opposed enlarged areas does not exert a resultant force and, therefore, exerts no force against the valve stem tending to restrict its movement. Since the forces generated by the pressurized fluid tend to cancel each other out, the valve stem may be moved with minimal effort, regardless of the level of fluid pressure in the system.
In one application of the valve, the aforementioned valve stem is incorporated in a valve body which, in turn, may be lowered into well tubing to block off fluid flow at a desired location. The valve stem may be readily moved with respect to the valve body to open and close the valve even at such a remote location, using ordinary tools available at a well site. In one embodiment, the valve stem is slidably retained in the valve body by a shear pin such that, if the valve body becomes jammed in the tubing, the valve stem may be removed by exerting a force thereon sufficient to cause the shear pin to break.
The same principles may be utilized in a surface type valve having the valve stem directly connected to a handle or other manually manipulable means. In this configuration, one of the enlarged areas has a length sufficient to block the inlet and outlet passage in the valve body when in the closed position. When in the opened position, the fluid passes between the enlarged areas and around a reduced diameter stem which is positioned between the inlet and outlet. Since, in both the opened and closed positions, the resultant forces caused by the fluid pressure acting on the valve stem cancel each other out, the stem may be readily moved with minimal effort.
In another alternative embodiment, the principles of this invention may be accomplished by incorporating a central passageway extending completely through the valve stem in the longitudinal direction to allow fluid on one side of the enlarged area to communicate with the fluid on the other. This configuration is particularly useful when the valve is designed as a check valve which is manually movable between the opened and closed position, and vice versa. When in the closed position, one of the two enlarged areas is interposed between the valve inlet and outlet to thereby preclude fluid flow. The valve will not move since the enlarged sections are of equal area and are acted upon by equal pressures. When it is desired to open the valve, the valve element is manually displaced so as to remove the enlarged area from blocking the fluid outlet. Again, the balancing of forces maintains the valve element in its opened position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional side view of a valve according to the invention in its closed position and situated at the bottom end of the tubing string of a well;
FIG. 2 is a sectional side view of the valve of FIG. 1 shown in its opened position;
FIG. 3 is a cross-sectional view of the valve according to the invention taken along lines 3--3 in FIG. 1;
FIG. 4 shows a cross-sectional view of the valve according to the invention taken along lines 4--4 in FIG. 2;
FIG. 5 is an enlarged sectional view showing the shear pin connection taken along lines 5--5 in FIG. 2;
FIG. 5a is a partial, sectional view of the valve according to the invention showing an alternative sealing arrangement;
FIG. 6 is a sectional side view of an alternative embodiment of the valve according to the invention shown in its closed position and attached to a standard tubing plug in place of the usual check valve;
FIG. 7 is a side sectional view of the valve of FIG. 6 shown in its opened position;
FIG. 8 is a cross-sectional view taken along lines 8--8 in FIG. 6;
FIG. 9 is a cross-sectional view taken along lines 9--9 in FIG. 6;
FIG. 10 is a cross-sectional view taken along lines 10--10 in FIG. 7;
FIG. 11 is a side sectional view of a third embodiment of the valve according to the invention shown in its closed position; and
FIG. 12 is a side sectional view of the valve of FIG. 11 shown in its opened position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 through 5 show a first embodiment of the valve according to the invention in which the valve assembly, indicated generally at 10, is disposed within well tubing 12 having seating nipple 14 attached thereto. The valve assembly 10 comprises valve body 16 having valve stem 18 slidably retained therein through central aperture 20. Valve body 16 has a beveled radially outwardly extending annular ridge 22, the outer diameter of which is greater than the inner diameter of seating nipple 14 such that it rests upon the upper, chamfered edge of seating nipple 14. Rubber gasket 24 is retained on valve body 16 by any known means and serves to act as a seal between annular ridge 22 and seating nipple 14. Lower valve body 16a has opening 26 extending therethrough which communicates with lower well opening 28.
Opening 26, in turn, communicates with generally U-shaped passageways 30, each of such passageways comprising generally radially extending portions 30a and 30b and interconnecting longitudinal portions 30c. Although it has been found that eight of these passageways provide a sufficient volume of fluid flow through the valve, quite obviously any other number could be utilized depending upon the characteristics of each individual application. Radial portion 30b communicates with passageway 20 which extends longitudinally through the remainder of the valve body 16. Radial ports 32 permit fluid communication between the opening 20 and the interior of the well tubing 12. Again, eight radial ports 32 have been found to provide sufficient volumetric fluid flow, however, any number of such ports could be utilized without exceeding the scope of this invention. Valve body 16 also defines inner chamber 34 which communicates with opening 20 at its upper end.
Valve stem 18 is slidably retained in opening 20 through valve body 16 and its movement relative thereto is normally limited by shear pin 36. Shear pin 36 is fixedly attached to valve body 16 and has its radially innermost end extending into slot 38 in valve stem 18. Under normal circumstances, shear pin 36 limits the movement of valve stem 18 with respect to valve body 16. However, if the valve assembly 10 gets stuck in the well tubing 12 due to a crimp in the well tubing, etc., a force can be exerted on valve stem 18 which is sufficient to break shear pin 36 and allow the removal of the valve stem from the well. It is envisioned that a shear pin having a shear force of 2500 pounds would be used in such an environment, although shear pins having other shear values may be utilized.
Reduced diameter valve portion 40 interconnects distal end portion 42 with valve stem 18. The diameter of valve portion 40 is substantially smaller than the diameter of opening 20 to allow fluid passage from ports 32, opening 20 and passages 30b when the valve is in the opened position, as shown in FIG. 2. The diameter of distal portion 42 is substantially the same as that of valve stem 18. The areas of each of these elements that are exposed to the fluid pressure are also substantially equal, thereby negating any resultant force exerted on valve stem 18 by the fluid pressure within the valve body. Regardless of this pressure, the forces will substantially cancel each other out, thereby minimizing the external force required to move the valve stem 18 with respect to valve body 16. One or more O-ring seals 44 may be provided on valve stem 18 and distal portion 42 to prevent passage of fluid between these elements and the surrounding walls. O-ring seals 44 sealingly engage the interior of opening 20 and the interior of the wall defining chamber 34 as shown. The diameter of the valve stem located above the uppermost O-ring 44 may be made larger than the diameter of the remainder of valve stem 18 to reduce the possibility of cutting or deforming the O-rings as they pass by radial ports 32 during the opening and closing of the valve. Attaching portion 46 is rigidly attached to the upper end of valve stem 18 and may be internally threaded to receive rod 48 which extends upwardly for a sufficient distance (e.g. about 18 inches) to permit the attachment of a conventional fishing tool of a wire line assembly (not shown) by means of which the valve assembly may be lowered into the tubing string and/or the valve may be opened and the assembly pulled out of the tubing.
Valve body 16 also defines relief port 50 which, as shown best in FIG. 3, allows fluid to communicate between chamber 34 and the interior of well tubing 12, and permits the equalization of pressures therebetween. Relief port 50 prevents the increase in pressure in chamber 34 as valve stem 18 is moved downwardly, as shown in FIG. 1, thereby minimizing the force necessary to move valve stem 18. The portion of relief port 50 in chamber 34 may be defined by a semi-cylindrical arcuate passageway located in valve body 16 in the wall defining the lower surface of chamber 34, and a correspondingly oriented semi-cylindrical channel in the bottom portion of valve stem element 42. As is clearly shown in FIG. 3, relief port 50 does not communicate with any of the passages 30, but passes between them to provide a pressure relief for chamber 34. Relief port 50 also provides an entrance for fluid to enter chamber 34 as the valve stem 18 is moved upwardly to open the valve, thereby preventing the formation of a vacuum between distal portion 42 and the valve body 16 defining chamber 34. This also serves to minimize the force necessary to open the valve.
In operation, for hydrotesting a tubing string, the valve assembly with the valve stem in its lower position may be seated in the bottom section of tubing at the surface and this section and succeeding sections then lowered into the well, or the valve assembly may be lowered into an existing tubing string already in place in the well. In the latter case, the valve 10 is lowered down into well tubing 12 by way of rod 48 attached to the fishing tool of a wireline unit at the surface until sealing ring 24 contacts the upper chamfered edge of seating nipple 14, as shown in FIG. 2. During the lowering of the assembly, the valve is open and fluid communication between the well tubing above and below the valve is accomplished via radial ports 32, passage 20, passages 30 and opening 26. As mentioned above, the fluid pressure exerts no resultant force on valve stem 18 due to the substantially equal areas of valve stem 18 and distal end portion 42. The forces exerted on the opposed surfaces in the reduced diameter portion 40 cancel each other out. When the assembly is seated, valve stem 18 continues to move downwardly by inertia until upper O-rings 44 pass radial ports 32, as shown in FIG. 1. The fishing tool and wireline may be removed during hydrotesting of the tubing string. O-rings 44 seal against the interior of passageway 20 thereby preventing any fluid communication between radial ports 32 and passages 30. Once the hydrotesting has been completed, the valve 10 may be easily opened and the assembly removed regardless of the pressures existing within the tubing. Thus, the fishing tool may be lowered in the tubing by means of the wireline unit which is mechanically powered. The fishing tool "catches" rod 48 and the wireline operator will spool in his wireline until a slight resistance is felt. The resistance is caused by the bottom of slot 38 contacting shear pin 36. When this slight resistance is felt the wireline operator will stop his spool and wait until the pressure has equalized as the valve is open. When the pressure has equalized, usually within a few minutes, the entire valve assembly may then be easily withdrawn from the well with the wireline unit.
As an alternative to utilizing seal ring 24 to seal against the chamfered upper edge of seating nipple 14, chevron seals may be located on the lower valve portion 16a, as shown in FIG. 5a. Chevron seals 52 may be of any known variety and serve to seal against the inner surface of seating nipple 14, as shown. Chevron seals 52 may be retained in place by threadingly engaging a nut 54 with valve body portion 16a.
It is also envisioned that the concepts discussed above can be used in an equalizing valve on the bottom of an Otis mandrel, which is widely used in the oil and gas industry. A mandrel of this type (type W Otis mandrel MS 321) is used to seal off a portion of the well tubing by inserting the mandrel into the tubing and expanding an expander element against the inner sides of the tubing to make a pressure seal. The mandrel has a longitudinal passage extending through its length, the bottom of which is sealed by a check valve. Typically, this check valve is a type C Otis plug bean MS 356 and comprises a valve body which is threadingly engaged onto the bottom of the mandrel and contains a spring biased check valve therein. The check valve serves to seal off the passageway extending through the mandrel. The higher pressures in the lower portion of the well also exert a closing force on this check valve and, in the case of high pressure wells on the order of 2000 psi, renders the opening of the valve, necessary in order to remove the mandrel, extremely difficult and time consuming. The currently accepted procedure for opening such a valve is for the wire line operator to tap on the valve elements with a probe located on the fishing tool which removes the mandrel from the well tubing. The probe extends down through the longitudinal opening in the mandrel in order to contact the check valve. Each time the valve is contacted, it opens for an instant and lets a small amount of gas therethrough. This procedure is continued until the pressures on either side of the check valve are substantially equal, at which time the mandrel may be removed. This procedure is extremely time consuming and in high pressure wells, has taken as long as a day and a half in order to equalize pressures and remove the mandrel.
The principles of the instant invention can be utilized in a valve structure which replaces the standard type C Otis check valve on the bottom of the mandrel and substantially reduces the amount of time required for pressure equalization and removal of the mandrel. This embodiment of the invention is shown in FIGS. 6-10 and will be described in conjunction with a standard type W Otis mandrel. It is believed that this type of mandrel is well known in the industry and further detailed description of it is believed to be unnecessary. The lower portion of the mandrel is indicated as element 56 in FIGS. 6 and 7 and has passageway 58 extending therethrough along its longitudinal axis. The rubber element that is expanded against the inner surface of well tubing 60 is located above the portion of mandrel 56 shown in the drawings, and serves to seal off the inner well opening except for the passageway extending through the mandrel.
Valve body 62 is threadingly engaged onto the bottom of mandrel 56, the body being generally cylindrical with a central longitudinal opening 64 and a plurality of radially oriented ports 66 extending through the sidewall of valve body 62 so as to allow communication between longitudinal opening 64 and the interior of the well tubing 60. Cap 68 is threadingly engaged onto the opposite end of valve body 62 and may be provided with O-ring seal 70 to prevent fluid seepage into opening 64 around the threaded connection. Valve element 72 is slidably disposed in opening 64. Valve element 72 is generally cylindrical in nature and has O-ring seals 74 and 76 located adjacent its upper and lower ends, respectively. Pressure equalization port 78 extends through valve element 72 generally coincident with its longitudinal axis.
When the mandrel is to be inserted into the well tubing, the valve is threaded onto the bottom of the mandrel with the valve element 72 positioned as shown in FIG. 6. The positioning of the valve element is achieved by removing end cap 68 and manually moving valve element 72 against the lower portion of the mandrel, such that O-rings 74 and 76 are on either side of ports 66. In this position, the valve is closed and will prevent any fluid communication between ports 66 and mandrel passageway 58. Since the exterior of the mandrel is sealingly engaged against the interior of well tubing 60, all communication between the upper and lower portions of the well is cut off.
When it is desired to remove the mandrel, the standard fishing tool is attached thereto and its probe is inserted into longitudinal opening 58 such that it contacts the top of valve element 72. However, since the vertical forces of the well fluid on the valve element are equal and opposite, no resultant forces are generated on this element and, consequently, there is no excessive force tending to maintain the valve element in its closed position. The probe may easily push valve element 72 to its lowermost position as shown in FIG. 7, thereby quickly opening the valve and equalizing the pressures above and below the mandrel. Pressure equalization port 78 allows fluid communication between the ends of valve element 72 and, since they are of equal area, no resultant forces are generated on this element. Once the mandrel assembly has been removed from the well, valve element 72 may be manually moved to its closed position for subsequent usage. The elimination of any resultant forces acting on the valve element reduces the pressure equalization time, which has required a day and a half in the most severe cases, to a few minutes.
The instant invention is also applicable to surface valves and is not merely restricted to valves utilized in a well environment. A surface valve utilizing applicant's invention is shown in FIGS. 11 and 12 and comprises valve body 80 defining ports 82 and 84 having a generally coincident longitudinal axis. Valve body 80 further defines passageway 86 having its longitudinal axis oriented generally perpendicular to the axes of ports 82 and 84. Valve element 88 is slidably disposed in passageway 86 and has a plurality of O-rings 90, 92 and 94 disposed thereon so as to sealingly engage the interior surface of passageway 86. Valve element 88 has enlarged end portions 96 and 98 interconnected by reduced diameter portion 100. Operating handle 102 is rigidly connected to portion 96 and may have a sealing or packing element 104 around its connection to prevent fluid leakage.
As shown in FIG. 12, when the valve is in the open position, reduced diameter portion 100 is disposed in passageway 86 and allows fluid communication between ports 82 and 84 through this passageway. O-ring seals 92 and 94 prevent fluid from leaking through the top or bottom of passageway 86. Since the areas of enlarged portions 96 and 98 exposed to the fluid are of equal areas, no resultant force is exerted on the valve element 88 by the fluid passing through the valve. In order to close the valve, handle 102 is pushed downwardly, which positions enlarged area 96 between the ports 82 and 84 such that O-rings 90 and 92 prevent fluid communication between ports 82 and 84, as shown in FIG. 11. Again, no resultant forces are generated on the valve assembly 88 by the fluid, since the forces acting on element 96 cancel each other out.
As can be readily seen from the description of the foregoing embodiments, applicants' invention provides a pressure balanced valve that requires minimal operative force to open or close the valves regardless of the fluid pressures associated with the system. The foregoing description of the preferred embodiments are for illustrative purposes only and should not be construed as in any way limiting the scope of coverage of this invention, which is solely defined by the appended claims.
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A pressure balanced valve is disclosed which minimizes the force necessary to move the valve between an opened and a closed position even when used to shut off the flow of a high pressure fluid. The valve stem in combination with a pressure relief port on the valve stem balances the pressures acting on the valve to relieve any differential pressure which would tend to maintain the valve either open or closed. In the absence of any differential pressure, the valve stem is not forced in any direction since the resultant of the forces due to the cross-sectional areas of the valve stem is zero, i.e., all of the forces are cancelled. The balancing of the pressure is achieved by a series of passages in the valve body which are selectively interconnected by movement of a valve stem within the body. The invention may be utilized in a down-hole well environment or in above-ground piping systems.
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BACKGROUND OF THE INVENTION
The manufacture of finely divided magnesium (i.e. "atomized" magnesium) for use in pyrotechnic devices such as flares, military applications and other purposes is well known. One process used is to eject a stream of liquid magnesium from a nozzle and then to hit the liquid magnesium stream, as it issues from the nozzle, with a high velocity jet of inert gas, such as helium. The impact of the helium jet on the liquid magnesium stream breaks the liquid stream into very finely divided droplets which, when passed into a large chamber containing the inert gas, cool in said chamber to form solid magnesium powder of such fineness as to be commonly referred to as "atomized" magnesium.
Such a process, however, could not, prior to the present invention, be operated continuously because some of the liquid magnesium issuing from the nozzle would after a period of operation deposit and collect in solid form on the end of the nozzle, which in turn would interfere with and disrupt the inert gas jet to an extent such that the operation would have to be discontinued.
Shut-down of the apparatus to remove the build-up on the nozzle is time consuming and expensive. Once the operation is interrupted for any length of time the liquid magnesium cools and solidifies in the lines.
SUMMARY OF THE INVENTION
According to the present invention, a magnesium powder manufacturing apparatus is provided in which build-ups on the atomizing nozzle may be removed during operation, from time to time without stopping the flow of inert gas or liquid metal, and by means which does not contaminate the resultant powdered magnesium product.
When a nozzle build-up is seen or otherwise sensed, an abrasive powder (preferably magnesium oxide powder) is injected into the inert gas stream in such amount and for such period as to wear off or knock off the solid build-up (primarily solid magnesium) around the end of the nozzle. Thus the build-up is removed before it interferes with the operation and the apparatus can be operated continuously, without having to be shut down on account of solid build-up of magnesium or a magnesium compound (such as magnesium oxide or nitride) on the nozzle.
The apparatus of this invention can also be applied to alloys of magnesium containing at least about 60% by weight of magnesium. One such alloy is a magnesium aluminum alloy containing 65% by weight magnesium and 35% by weight aluminum which is used in the steel industry for desulfurization. Other alloys include magnesium zinc, magnesium nickel, magnesium-calcium alloys containing at least about 60% by weight magnesium.
Furthermore, no impurities or contaminants are introduced into the final product because the preferred abrasive, magnesium oxide, introduced only in very small quantity and for short times is merely the oxidized form of the metal powder being manufactured.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a typical nozzle assembly of the apparatus according to the invention mounted in the sidewall of a magnesium powder collecting tank for manufacturing atomized magnesium by projecting a horizontal spray of magnesium into the collecting tank. The nozzle assembly could alternatively be mounted in the topwall of the tank, for vertical spray applications or at any other convenient angle of spray.
FIG. 2 shows the entire apparatus of the invention mounted in a wall of magnesium collecting tank as in FIG. 1. The nozzle assembly is shown in cross-section and an exploded view of the cross-section of the junction of the abrasive material conduit and the pressurized gas conduit is included.
FIG. 3 is a right side view of the nozzle assembly of the apparatus of FIG. 2.
FIG. 3A is a sectional view of the nozzle assembly of FIG. 3 taken along line 3A--3A of FIG. 3.
FIG. 4 is a left side view, partly in section, of the nozzle assembly.
FIG. 4A is a sectional view of the outlet section of the nozzle assembly of FIG. 4 taken along lines 4A--4A of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, the apparatus of the invention, shown generally by 11, comprises a nozzle assembly 19 mounted in a sidewall 12 of collecting tank 13. The tank 13 has a lower conical section 14 in which the finely divided or atomized magnesium powder settles to be later withdrawn through a sealed port or opening (not shown) at the bottom of the tank.
The apparatus 11 also includes (FIG. 2) a melting pot 15 into which is introduced magnesium metal. Means for melting the magnesium metal such as fuel gas burners 16 are located beneath pot 15. A pipe 17 having an inlet opening beneath the surface of the liquid magnesium in melting pot 15 leads from the top of melting pot 15 downwardly below the level of the melting pot to inlet 18 of nozzle assembly 19 mounted in sidewall 12 of tank 13. Heating means such as burners 20 and 36 are located below and alongside a section of pipe 17 between the melting pot 15 and nozzle assembly 19. An electrical resistance heater 21also may be provided, if desired. Inert gas from a pressurized source (not shown) located externally of tank 13 is also fed from inlet 32 through conduits 31 and 22 to inert gas inlet 23 of the nozzle assembly. Flow control valve 48 in conduit 32 regulates gas flow from the source to the nozzle assembly.
A reservoir 25 containing an abrasive material located above conduit 22 is connected by conduit 29 to conduit 32 and by conduit 26 to conduit 22.
Conduit 26 extends from the bottom of reservoir 25 to the conduit 22 and it has inserted therein an "on" and "off" valve 27 and a metering orifice valve 28 for regulating the rate of flow of abrasive material from the reservoir into the conduit 22. A positive pressure is maintained in the top section of reservoir 25, above the powdered abrasive material in said reservoir. A valve 52 controls the flow of gas through conduit 29.
The inert gas flowing through conduit 31 and the abrasive laden inert gas flowing through conduit 22, are heated (for example to about 1000 degrees F. by burners 50).
FIG. 2 additionally shows an exploded cross-sectional view of the union 33 of conduits 26 and 22. The internal diameter of conduit 22 is constricted at 34 so that a pressure drop will occur in conduit 22 at its intersection with conduit 26 as gas is ejected from the constriction, thus effecting aspiration of abrasive through conduit 26. Conduit 26 is also constricted at 35 to further control the flow of abrasive material through conduit 26.
The nozzle assembly 19 of FIG. 2 includes two engageable cylindrical sections; inlet section 37 and outlet section 38 shown in detail in FIGS. 3, 3A, 4 and 4A. Inlet section 37 is provided with a central liquid magnesium inlet 18 and an offset inert gas inlet 23 which are connected with conduits 17 and 22 respectively, as hereinbefore described. A nozzle 39 projects from the inlet section 37 and it has a bore 40 which communicates with and is an extension of inlet opening 18 of inlet section 37. Outlet section 38, as shown in FIG. 3A and in more detail in FIGS. 4 and 4A, is provided with a gas receiving chamber 41 which connects with gas inlet 23 of section 37 and also with an annular chamber 42 communicating with chamber 41 and surrounding nozzle 39. This annular chamber 42 is constricted in the area of the nozzle outlet, forming a narrow gas outlet annulus 45. Between gas receiving chamber 41 and annular chamber 42 is a connecting passage 43 (FIG. 4). The arrows shown in FIGS. 3A, 4 and 4A show the path of inert gas flow from inlet opening 23 through the chambers 41, passage 43, chamber 42 to the outlet annulus 45 of the outlet section. A portion of the wall of connecting passage 43 is grooved as shown in 44, the groove being wider and deeper in the vicinity of chamber 41 and narrower and shallower in the vicinity of the central portion of annular chamber 42. This tapered groove imparts a swirling motion to the inert gas received in chamber 41 from inlet 23 and discharged from chamber 41 into the annular chamber 42 and through the inert gas jet opening 45.
In operation of the apparatus of the invention to produce "atomized" magnesium, magnesium metal is placed in melting pot 15 and in pipe 17 and then heated to melting by burners 16, 20 and 36. Because the inlet to pipe 17 is located below the surface of the magnesium after the same liquifies, the liquid magnesium will then start to flow through pipe 17 by a siphoning action. The liquified magnesium flows by gravity through conduit 17 to the nozzle inlet 18 of nozzle assembly 19 and on out through nozzle 39. The continuity of molten magnesium flow can be maintained solely by the siphoning action or maintained by a pump (not shown) as desired. Alternatively, or in addition, flow of liquid magnesium from pot 15 through line 17 and nozzle 39 may be assisted or maintained by pressurizing pot 15 with inert gas. The liquid magnesium in pot 15 is preferably maintained at a temperature of about 1425 degrees F. Burners 20 and 36 insure that the molten magnesium will not solidify in line 17, which is open throughout its length and thus provides for continuous flow of magnesium metal through line 17 and out nozzle 39 so long as molten magnesium is maintained at the proper level in pot 15. At the same time, pressurized gas flows through line 31 to gas inlet 23, enters receiving chamber 41, is directed inwardly through connecting passage 43 and notch 44 into annular chamber 42 where it swirls at high velocity around nozzle 39 and is ejected as a swirling jet at high velocity through annular gas outlet 45 into the tank. The ejected gas impinges upon the ejected molten magnesium stream from nozzle 39 and atomizes the magnesium into a spray of finely divided droplets inside tank 13.
There are no valves in the liquid magnesium line so the flow is continuous so long as liquid metal is maintained in the pot with its surface above the inlet to line 17 (when a siphoning feed is utilized). However, the inert gas flow is regulated by a pressure control regulator 30 in line 31, and the flow of abrasive powder (such as magnesium oxide) from reservoir 25 downwardly into inert gas conduit 22 is regulated by a flow regulating valve or metering orifice 28.
Reservoir 25 has a cover so that the inert gas introduced therein through by-pass line 29 can be maintained (in the top section of the reservoir above the abrasive powder) at a pressure sufficient to enable the abrasive powder to flow downwardly through conduit 26 and to be entrained in the inert gas flowing to gas jet nozzle opening 45 through conduit 22. Such flow is insured by a positive pressure above the abrasive material level maintained by pressure from inlet 32 via equalizing line 29. Abrasive material in conduit 26 is aspirated by and mixed with the pressurized gas in conduit 22 at junction 33 of these two conduits. The abrasive material, mixed with the gas, contacts and abrades the solidified magnesium on the nozzle or on the sides of the orifice 45 until it is completely removed. The abrasive material ejected into tank 12 with the gas, molten magnesium and solidified magnesium becomes a minor impurity in the total yield of atomized magnesium.
After the build-up on nozzle 39 or on the sides of orifice 45 is removed, valve 27 is closed and the atomization process continues as before without interruption. In practice the abrasive material can be introduced to the system at regular intervals to ensure that no significant build-up of solid magnesium occurs at the nozzle.
The abrasive material used in this invention can be any particulate material which has abrasive properties and does not react with magnesium such as silica sand, carborundum, aluminum oxide and the like. Preferably, however, magnesium oxide (magnesite) is employed as the abrasive material. By using the oxidized form of the metal being atomized, i.e. magnesium, contamination of the so-formed atomized magnesium is substantially eliminated.
Once liquid magnesium is ejected into tank 13 from nozzle 39 simultaneously with the ejection of a high velocity stream of swirling helium from nozzle 45, the gas jet impinges forcefully on the liquid metal and causes it to break up into very finely divided droplets, in the form of a "spray", which is projected into the helium atmosphere in the tank 13. The droplets then cool and solidify while suspended in the helium gas, to form "atomized" magnesium particles which settle by gravity to the bottom of the tank, from which they are removed.
During the operation as described above small amounts of magnesium and/or magnesium compounds may solidify or otherwise deposit on or around the edge of the liquid metal nozzle 39 or on the side of orifice 45 against outlet section 38. If this deposit accumulates to a degree disrupting the flow or shape of the inert gas jet issuing from gas nozzle 45, there will be an adverse effect on the size or uniformity or other characteristics of the magnesium particles being formed and collected in the tank and when this happens the said deposit must be removed, without interrupting the operation and without introducing impurities into the final product.
This removal is effected by opening valve 27 and allowing magnesium abrasive powder (magnesium oxide) from reservoir 25 to flow downwardly through conduit 26 into the inert gas stream flowing through line 22. When the gas containing such abrasive issues from orifice 45 and impinges upon the edges of this orifice upon which the deposit has accumulated, the deposit is broken off or worn away by the abrasive until it disappears to the point where the orifice is free of deposit and the operation once again can proceed normally, as originally begun.
Only a relatively "short burst" of abrasive powder is required, and the abrasive normally is introduced only at intervals so that the operation is predominately carried out so that only pure magnesium is introduced into the tank, of the same purity placed in the melting pot 15.
When a burst of abrasive powder is fed into the inert gas stream passing through conduit 22, the abrasive ends up in tank 13, and could become an "impurity" in the final product. However, the use of magnesium oxide as the abrasive provides an end product that is completely magnesium except for very small amounts of oxygen combined with a very small amount of the magnesium in the oxide form. The result is that for practical purposes for which it is used, substantially pure magnesium powder, completely absent of any detrimental impurities is produced.
The apparatus of the invention may be used to produce atomized particles of magnesium alloys containing at least 60% by weight of magnesium such as a 65% by weight magnesium- 35% by weight aluminum alloy and other alloys of magnesium.
In order more particularly to describe and illustrate the present invention, the following examples are given of two applications of the invention. These examples are not to be considered as limiting, but only as typical of certain of the actual applications of the present invention. In each example the apparatus of FIGS. 1 to 4A was employed.
SPECIFIC EXAMPLES
Example 1
In this Example, magnesium in pot 15 was heated to 1400° F. and caused to flow in conduit 17 to nozzle assembly 19 at a pressure of 27 inches of water. Helium gas in line 32 at 100 psig was also introduced to the nozzle assembly at 250 scfm. The nozzle diameter was 0.300 inches and the diameter of the gas outlet annulus 45 was 0.400 inches. The atomizing rate of magnesium from the nozzle was about 300 pounds per hour. At intervals of about 20 minutes during atomization, about 1 pound of silica sand in reservoir 25 was introduced into conduit 22 to completely clear obstructions from the nozzle. The total magnesium powder produced was 2520 pounds.
Example 2
In this Example, magnesium in pot 15 was heated to 1410° F. and caused to flow in conduit 17 to nozzle assembly 19 at a pressure of 27 inches of water. Helium gas was again employed at a pressue of 60 psig and a flow rate of 240 scfm. The nozzle diameter was 0.350 inches and the diameter of the gas outlet annulus 45 was 0.450 inches. The atomizing rate of magnesium from the nozzle was 400 pounds per hour. At eight times during the atomization, about 61/2 ounces of magnesite (60 mesh) from reservoir 25 was introduced into conduit 22 to remove magnesium build-up at the nozzle. The total atomized magnesium produced was 1600 pounds.
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An apparatus for continuously manufacturing finely divided magnesium, and similar metals, in which a liquid stream of magnesium ejected from a nozzle is impacted by a high velocity stream of inert gas to "atomize" the liquid magnesium, including means for the intermittent entrainment of an abrasive powder in the inert gas stream to remove the build-up of solid magnesium or magnesium compounds that otherwise would collect on the end of the nozzle and interfere with continuous operation of the "atomizing" process.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a microbiological process for preparing sphingolipids, especially, tetraacetylphytosphingosine(TAPS), using a novel yeast Pichia ciferrii DSCC 7-25 under defined fermentation conditions. Further, this invention concerns a novel yeast Pichia ciferrii DSCC 7-25 and it's isolation method from the parental Pichia ciferrii strain ATCC 14091.
2. Description of Prior Art
The term "sphingolipids" refers to a group of lipids derived from sphingosine. Further, sphingolipids contain sphingosine, dihydrosphingosine or phytosphingosine as a base in amide linkage with a fatty acid. Sphingosine or phytosphingosine bases may be used as starting materials in the synthesis of a particular group of sphingolipids, namely ceramides. Ceramides are main lipid component of the stratum corneum, which has an important barrier function. Therefore, the skin cosmetic products having ceramides has a function for moisture-retaining properties of the skin.
Currently, heterogenous sphingolipid preparations for cosmetics are mainly extracted from animal sources. Obviously, this is a rather costly process on an industrial scale. Moreover, it has been found that these materials are potentially unsafe due, for example, to the possible presence of bovine spongiform encephalomyelitis (BSE) in bovine tissue. Thus, the cosmetic industry has demonstrated an increasing interest in new sources of pure, well-defined sphingolipids, which are obtained from sources other than animal tissues.
Microorganisms such as the yeasts Pichia ciferrii, formerly indicated as Hansenula ciferrii and Endomycopsis ciferrii (Stodola and Wickerham, 1960; Wickerham and Stodola, 1960; Wickerham et al., 1954; Wickerham, 1951) have been found to produce sphingolipids as such, as well as sphingosine, phytosphingosine and/or derivatives thereof. This discovery provides sources for sphingolipids themselves and for starting materials for the production of other commercially valuable compounds which could offer a valuable alternative to the use of animal sources of these compounds.
The biosynthetic pathway of tetraacetylphytosphingosine(TAPS) in Pichia ciferrii was described by Barenholz et al (1973). The biosynthetic pathway for sphingosine and dihydrosphingosine is proposed by Dimari et al. (1971). Barenholz et al. (1971 & 1973) investigated the metabolic background of the production of TAPS and other sphingolipid bases in four strains of Pichia ciferrii. In the later study, the profiles of four microsomal enzymes specific for the biosynthesis of acetylated sphingosine bases of a low (Pichia ciferrii NRRL Y-1031, E-11, sex b, 8-20-57) and a high producer (Pichia ciferrii NRRL Y-1031, F-60-10) were compared. It was found that the specific activity of 3-keto dihydrosphingosine synthetase and the long-chain base acetyl-CoA acetyltransferase were increased 5-10 fold and 30 fold respectively, as compared with the low producer, whereas the activities of palmityl thiokinase and 3-ketodihydrosphingosine reductase were similar. This indicates that in the low producer, the activity of the 3-ketodihydrophingosine synthetase and the long-chain base acetyl-CoA acetyltransferase is the limiting steps in the synthesis of acetylated sphingosines. Under the defined growth conditions, Pichia ciferrii NRRL Y-1031 F-60-10 was found to produce 300 μmoles/L sphingosine (about 0.15 g/L) bases, of which, at least 250 μmoles/L were extracellular. Even where culture conditions were optimized for TAPS production, only 0.485 g/L TAPS (0.024 g TAPS/g dry yeast) was obtained (Maister et al., 1962).
Maister, using the F-60-10 mating type strain, was able to produce up to 300 mg/L in a pilot scale batch mode fermentation using glucose as a carbon source at 25° C. The TAPS produced is the D-D-erythroisomer, which has the same stereochemistry as the phytosphingosine occurring in the human skin. TAPS may be easily deacetylated to phytosphingosine. However, the yields of TAPS are too low to be of any practical value for commercial production.
Recently, many researchers have been attempted to improve the productivity of sphingolipids using mutant cells of Pichia ciferrii. According to the disclosure in WO 94/10131 (PCT/GB93/02230) maximum 2700 mg/L of TAPS production was reported using Pichia ciferrii NRRL Y-1031 F-60-10 in fed batch mode fermentation with 22.5 mg/L/h of TAPS productivity. Further, in WO 95/12683 (PCT/EP 94/03652), mutants derived from the mating type strain of Pichia ciferrii F-60-10 showed 40˜60% increased TAPS productivity compared to the parental strain. On the other hand, EP 0 688 871 A2 disclosed the selection and isolation of novel mutant of Pichia ciferrii F-60-10. Using this mutant, average 500˜1,000 mg/L and maximum 5,000 mg/L of TAPS production was reported, even though the productivity of TAPS is only 30˜42 mg/L/h.
However, any of the yeast strains studied to date, even Pichia ciferrii NRRL Y-1031 F-60-10, does not produce sufficient amounts of sphingolipid bases such as sphingosine, phytosphingosine or derivatives thereof to be an efficient, economically attractive source of such compounds.
In the early studies of Wickerham and his colleagues(Wickerham and Stodola, 1960), the production of sphingolipids, specifically TAPS was observed to be related to sexuality of the Pichia ciferrii strains. A high TAPS producer mating type NRRL Y-1031, F-60-10 was the one of the mating type isolate derived from the parental strain NRRL Y-1031(ATTC 14091), which was diploid. They also reported that a mating type of one sex(a) had a tentency of producing much higher level of TAPS than the other sex(b). It appeared, however, that there were some other genetic factor(s) affecting production of sphingolipids than sexuality. The strain Y-1031 mating type 11 produced much less TAPS than the strain Y-1031 mating type F-60-10 eventhough it had same sex type with the mating type F-60-10.
Based on the previous findings described above, we reasoned that genetic recombinations during meiosis of a diploid Pichia ciferrii, which results in formation of haploid spores, could give rise to a novel haploid mating type Pichia ciferrii strain with higher TAPS production yield than mating type F-60-10. In addtion, we employed a selection scheme that favors isolation of high producer of TAPS out of the spore pools. Calcium ion has been shown to affect the biosynthesis of sphingolipids by modulating activities of key enzymes involved in the pathway. Depletion of calcium ions by addition of EGTA that chelates calcium ions in the selection medium prevents the yeast cells to grow probably because it prvents synthesis of sphingolipids in the cell. Therefore, new haploid isolates that can grow in those selection environment are likely high producers of TAPS.
SUMMARY OF THE INVENTION
The object of the present invention is to provide novel yeast isolates of Pichia ciferrii, which were deposited to Korean Culture Center of Microorganism, Department of Food Engineering, College of Eng., Yonsei University, Sodaemungu, Seoul 120-749 Korea with accession number KCCM-10131 on Jun. 30, 1998 under Budapest treaty, for preparing tetraacetylphytosphingosine (TAPS) with high productivity.
Another object of the present invention is to provide a process for maximum production of TAPS using a novel isolate, Pichia ciferrii DSCC 7-25 (KCCM-10131) comprising the steps of:
i) a fermentation with the yeast strain until maximum concentration of TAPS in fermentation medium becomes 5˜15 g/L wherein
a) composition of YMgl medium comprises yeast extract, malt extract, peptone, glycerol containing CaCl 2 and citrate
b) temperature of cultivation is 22˜28° C.;
c) agitation speed of the medium is 400˜600 rpm;
ii) transfering the fermentation mass to aging tank;
iii) separating the TAPS using organic solvent; and
iv) purifying the TAPS by silica gel column chromatography.
The other object of the present invention is to provide the process for maximum production of TAPS using a new Pichia ciferrii strain DSCC 7-25 (KCCM-10131) characterized in the fermentation is a batch fermentation, and the composition of YMgl medium comprises 0.2˜0.4 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 8.0˜12.0 (w/v)% of glycerol containing 5˜15 mmole of CaCl 2 and 0.4˜0.7 (w/v)% of citrate.
The further object of the present invention is to provide the process for maximum production of TAPS using a new Pichia ciferrii strain DSCC 7-25 (KCCM-10131) characterized in the fermentation is a fed batch fermentation, and the composition of YMgl medium comprises 0.3˜0.5 (w/v)% of yeast extract, 0.3˜0.5 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 15.0˜18.0 (w/v)% of glycerol containing 10˜20 mmole of CaCl 2 and 0.5˜0.9 (w/v)% of citrate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the TAPS production in a fed batch fermentation using DSCC 7-25.
DETAILED DESCRIPTION OF THE INVENTION
The novel Pichia ciferrii DSCC 7-25 strain used in the present invention are isolated by following methods, in which any mutagenesis steps are not involved.
The parental diploid yeast Pichia ciferrii ATCC-14091 is cultivated in the YMgl medium 0.2˜04 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 2.5˜3.5 (w/v)% of glycerol! with agitation, and is spread in the spore formation medium 3˜7% of malt extract and 4˜5% of agar!. Then, hat-shape spores are obtained, and single spores are selected by heat shock and cell wall degrading enzymes such as glusulase or Zymolyase that hydrolyze the cell wall of vegitative cells but not that of spores. This treatment efficiently enriches spores from the sporulated cell cultures, especially from the poorly sporulated cell cultures. For the selection of obtained single spore yeast derivatives, the selected cells are cultivated in YMgl plate medium 0.2˜0.4 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 2.5˜3.5 (w/v)% of glycerol and 2˜30 mmole of EGTA!, then cells are selected according to the amount of the release of sphingolipids. Finally, Pichia ciferrii DSCC 7-25 is isolated as the most sphingolipids release cell compared to those of other cells by the TLC and HPLC analysis. These isolates were deposited to Korean Culture Center of Microorganism with accession number KCCM-10131.
Followings are fermentation methods for producing TAPS using the selected yeast Pichia ciferrii DSCC 7-25.
The selected yeast Pichia ciferrii DSCC 7-25 are seed cultured in the cultivation medium, and concentrated cells are obtained. The seed cells are cultivated in YMgl medium with the yeast strain until maximum concentration of TAPS in fermentation medium becomes 5˜7 g/L. Further, the composition of YMgl medium comprises 0.2˜0.4 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 8.0˜12 (w/v)% of glycerol containing 5˜15 mmole of CaCl 2 0.4˜0.7 (w/v)% of serine and 0.4˜0.7 (w/v)% of citrate.
The formation of sphingolipids is controlled by the concentration of calcium cation (Ca ++ ), because the activity of serine-palmitoyl transferase (SPT) is enhanced by the addition of calcium cation in the medium. However, in the case of Pichia ciferrii NRRL Y-1031, the production of sphingolipids decreases in addition to the calcium cation in the medium.
On the other hand, the addition of serine in the medium increases the production of TAPS, since sphingolipids are biosynthesized by the reaction between serine and palmitoyl-CoA. Therefore, serine is also a limiting factor of biosynthesis of sphingolipids. According to the addition of calcium cation and serine in the fermentation medium, the productivity of TAPS has been increased up to 4˜5 fold in comparison to the productivity without adding such compounds in the medium.
The fermentation conditions are optimal, when the temperature of cultivation is 22˜28° C. and agitation speed of the medium is 400˜600 rpm. After the fermentation, the biomass including sphingolipids is transferred to aging tank. Then, the fermented biomass is aged for 2 days at 3˜5° C. The cells are precipitated and removed in the bottom of tank, and the sphingolipids are extracted by organic solvent. Finally, over 95% purified TAPS is obtained by the silica gel column chromatography.
The obtained TAPS can be converted to sphingosine or phytosphingosine by deacetylation in the basic solution, such as, KOH or NaOH. Using this sphingosine or phytosphingosine, the ceramide and it's derivatives can be obtained by N-acylation reaction with fatty acid. The fatty acid used for this reaction is any of saturated or unsaturated fatty acid having 6˜40 of carbon atoms and 0˜3 of double bonds. Further, this reaction is carried out by enzyme reaction or chemical reaction. In case of chemical reaction, carbodiimide, carbodiimidazole, 1,2-dihydroquinolon and/or hydroxybenzotriazole can be used as binding reagent.
The present invention can be explained more specifically by following examples. However, the scope of the present invention cannot be limited to following examples.
EXAMPLE 1
Isolation of Pichia ciferrii DSCC 7-25
A diploid Pichia ciferrii ATCC-14091 is cultivated in the YMgl medium 0.2˜0.4 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 2.5˜3.5 (w/v)% of glycerol! with agitation at 25° C. for three days. Then, the obtained cells are spread and cultivated in 0.1˜0.5 ml of the spore formation medium 3˜7% of malt extract and 4˜5% of agar! in room temperature for 7˜10 days. Then, hat-shape spores are obtained. The efficiency of spore formation is 6˜8%. Obtained spores are enriched by a combination of heat treatment and Zymolyase treatment for selection. The heat treatment is carried out to the 1˜2 ml of spore suspension (6˜10×10 7 cells/ml) at 55° C. for 1˜5 minutes and followed by treatment of Zymolyase 60,000 (10 mg/ml) for 0.5 to 2 hours at 30° C. First selection is carried out to isolate colonies different from the parental cells in shape, color and size. 50 colonies are selected among 400 colonies grown from the enriched spore pool.
For the second selection of obtained single spore yeast derivatives, the r selected cells are cultivated in YMgl plate medium 0.2˜0.4 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 2.5˜3.5 (w/v)% of glycerol and 2 30 mmole of EGTA! at 25° C. for 4 days. Then, cells are selected according to the amount of the release of sphingolipids. Following table shows the produced TAPS amount of secondary selected strains.
TABLE 1______________________________________The produced amount of TAPS of haploid isolates in YMgl mediumStrain Produced amount of TAPS(mg/L)______________________________________14091 1202-28 947-24 937-25 3197-28 1997-29 1847-40 1167-44 83F-60-10 241______________________________________
Finally, Pichia ciferrii DSCC 7-25 which is isolated as the most sphingolipids release cell compared to those of other cells by the TLC and HPLC analysis. The production yield of TAPS by Pichia ciferrii DSCC 7-25 is even 30% higher than that of F-60-10 strain which is known as the best strain for producing TAPS.
EXAMPLE 2
Comparision with Pichia ciferrii DSCC 7-25 and Pichia ciferrii F-60-10
The productivity of TAPS in the present invention is measured in comparision with that of Pichia ciferrii DSCC 7-25. Following is the comparision data between Pichia ciferrii DSCC 7-25 and Pichia ciferrii F-60-10.
TABLE 2______________________________________Comparision data between Pichia ciferrii DSCC 7-25 and Pichia ciferriiF-60-10 DSCC 7-25 F-60-10______________________________________Doubling time 1.5 3.0(hour)Concentration of biomass 29.7 15(g/L)TAPS Titre 319.sup.a 241.sup.b(mg/L)Specific yield of TAPS 10.7 16.1(mg/gdw)Volumetric productivity 4.6 1.7(mg TAPS/L/H)______________________________________ Fermentation condition: YMgl medium (3% of glycerol), 25° C., 250 rpm .sup.a : hours to the end of fermentation was 70 hours .sup.b : hours to the end of fermentation was 144 hours
As shown in the table, the strain DSCC 7-25 has much better volumetric productivity, by which the cost of production is determined.
EXAMPLE 3
Optimization of fermentation condition for Pichia ciferrii DSCC 7-25--synergistic effect of CaCl 2 and serine on the production of TAPS
The selected haploid strain Pichia ciferrii DSCC 7-25 are pr-cultured in the cultivation medium, and concentrated cells are obtained. The obtained cells are cultivated in YMgl medium at 30°C., in 250 rpm for 3 days. The composition of YMgl medium comprises 0.2˜0.4 (w/v)% of yeast extract, 0.2˜0.4 (w/v)% of malt extract, 0.3˜0.7 (w/v)% of peptone, 2.5˜3.5 (w/v)% of glycerol containing 10 mmole of CaCl 2 and 0.5 (w/v)% of serine.
The formation of sphingolipids is controlled by the concentration of calcium cation (Ca ++ ), because the activity of serine-palmitoyl transferase (SPT) is enhanced by the addition of calcium cation in the medium. However, in case of Pichia ciferrii NRRL Y-1031 mating type F-60-10, the production of sphingolipids decreases by addition of calcium cation in the medium. Following table shows the effect of calcium ion on the TAPS production between Pichia ciferrii DSCC 7-25 and Pichia ciferrii F-60-10.
TABLE 3______________________________________Calcium cation effect to TAPS production TAPS production (mg/L)Strain w/o CaCl.sub.2 CaCl.sub.2 (10 mM) Effect______________________________________DSCC 7-25 396 744 +1.9F-60-10 241 43 -5.6______________________________________
On the other hand, the addition of serine in the medium increases the production of TAPS, since sphingolipids are biosynthesized by the reaction between serine and palmitoyl-CoA. Following table shows the effect to TAPS productivity of calcium cation and serine to Pichia ciferrii DSCC 7-25.
TABLE 4______________________________________Production yield of TAPSMedium Production yield of TAPSYMgl + mg/L mg/gdw mg/L/H______________________________________None 284 22.3 3.94* CaCl.sub.2 816 58.3 11.33** Serine 784 54.8 10.88CaCl.sub.2 + Serine 1,065 88.2 14.79______________________________________ * CaCl.sub.2 10 mM, ** Serine 5 g/L
EXAMPLE 4
Optimization of fermentation conditions for Pichia ciferrii DSCC 7-25: batch and fed batch mode of fermentations for pilot scale
The fermentation conditions are further optimized in order to obtain maximum yield of TAPS production in a 500 L pilot scale fermentation. Optimized conditions include the temperature of cultivation is 22˜28° C. and agitation speed of the medium is 200˜250 rpm. In addition, other physiological factors affecting the production of TAPS as well as lipid biosynthesis are searched and the optimal concentrations and conditions for each element are determined. Those elements include pH, concentration of magnesium and calcium ion, organic acids such as citrate.
TABLE 5______________________________________Production yield of TAPS at a optimized conditionStrain Pichia ciferrii DSCC 7-25Mode of Fermentation Batch(1) Fed batch(2)______________________________________Doubling Time 1.5 1.5(hour)Concentration of biomass 41.6 85(g/L)TAPS titre 6206 14000(mg/L)Specific yield of TAPS 149.2 164.7(mg/L)Volumetric productivity 51.7 129.6(mg TAPS/L/H)______________________________________ Fermentation conditions: Temp, 25° C., Agitation, 210 rpm, Aeration, 0.2 vvm and the initial pH 7.5. (1): hours to the end of fermentation was 120 hours (2): hours to the end of fermentation was 108 hours
Since the production of TAPS by the yeast Pichia ciferrii is growth associated, supplement of a portion of the nutrients including glycerol has been shown to result in accumulation of TAPS and its derivatives in the culture until the nutrients are depleted. Using a fed-batch mode of fermentation, in which glycerol was added stepwisely to the fermentation broth up to 180 grams/L, the resulted production yield of TAPS and its derivatives reached to 14 grams/L as shown in the Table 5 and FIG. 1.
After the fermentation, the biomass including sphingolipids is transferred to aging tank. Then, the fermented biomass is aged for 2 days at 3˜5° C. The cells are precipitated and removed in the bottom of tank, and the sphingolipids are extracted by a process that is basically same as a process published by Wickerham et al. (1962) . Finally, over 95% purified TAPS is obtained by the silica gel column chromatography.
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The present invention relates to a microbiological process for preparing sphingolipids, especially, tetraacetylphytosphingosine(TAPS), using novel yeast cell Pichia ciferrii DSCC 7-25 under optimal fermentation conditions. Further, this invention concerns a novel yeast cell Pichia ciferrii DSCC 7-25 and it's isolation method from wild type of Pichia ciferrii strain.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119 to German Application 101 44 747.7 filed in Germany on 11 Sep. 2001, and as a Continuation Application under 35 U.S.C. §120 to PCT/CH02/00442 filed as an International Application on 13 Aug. 2002 designating the U.S., the entire contents of which are hereby incorporated by reference in their entireties.
BACKGROUND
[0002] A device is disclosed for continuous thermal treatment of granular bulk material, in particular for the crystallization of polymer granulate, such as polyethylene terephthalate (PET), with a product inlet terminating in a chamber being the very first chamber upstream and a product outlet after the last chamber downstream. In addition, a method is disclosed for the continuous thermal treatment of granular bulk material, in particular for the crystallization of polymer granulate, such as polyethylene terephthalate (PET), using the device.
[0003] A device is known from EP 0 712 703 A2, for example, which comprises a housing with an inlet and an outlet for plastic chips which are to be subjected to heat treatment. The interior of the housing is divided into a first large chamber and several smaller chambers by a plurality of separating walls, wherein the separating wall between the first chamber and the adjacent chambers is higher than the separating walls between the smaller chambers. All chambers can be supplied with gas from below via a sieve bottom to fluidize the chip product. During operation, the fluidized product flows via the upper edge of the respective separating wall from one chamber to the next. In the process, because of the effervescent movement in the respective fluidization chambers, undesired backmixing may occur as chips jump and/or are injected back from one chamber into the adjacent upstream chamber. This leads to different residence times for different chips, which necessarily causes differences in the product quality of the chips.
[0004] DE 195 00 383 A1 discloses a device for continuous crystallization of polyester material in granulate form. Thermal treatment is carried out in a cylinder-shaped treating space which is also supplied with gas from below via a sieve bottom in order to fluidize the granulate with the treatment gas. Although by using only a single treating space for fluidization purposes, cost savings are realized and stirring tools and the like are no longer necessary, this still does not make it possible to ensure a very narrow range of residence times of the particles and, consequently, a largely uniform product quality of the granulate.
[0005] EP 0 379 684 A2 discloses a device and a method for continuous crystallization of polyester material in granulate form. This device comprises two separately disposed fluidization chambers (fluidized bed apparatuses), wherein the first chamber is an effervescent fluidized layer with a mixing characteristic and the second chamber is a flow bed with a plug flow characteristic. While this combination of different fluidization chambers yields a surprisingly homogeneous product quality, each of the two separate fluidized bed apparatuses requires its separate circuit with channels, fans, heat exchanges for the gas injection and fluidization gas as well as cyclonic separators and/or filters for removing dust that is generated as a result of abrasion of the granulate particles.
SUMMARY
[0006] An inexpensive and easy-to-operate device as well as a method are disclosed which ensure a very narrow range of residence times of the granulate particles that are fluidized and thermally treated in the device and, therefore, a homogeneous product quality.
[0007] Insofar as the device described above is concerned, several adjacent fluidization chambers are provided with a separate sieve bottom each through which a fluidization gas can be injected into the respective chamber in order to fluidize the granulate, characterized in that such gas can exit via a gas outlet disposed in the roof area of the device and the first chamber occupies a large part of the total volume of all chambers, and wherein adjacent chambers have a fluid connection by means of product passages in the respective separating walls that are disposed between them.
[0008] This simple, compact construction can require particularly little material and space. The adjacent chambers significantly reduce heat losses and/or the required heat insulation and, ultimately, permit an energy-saving operation. In addition, as the number of chambers increases, the range of residence times of the granulate in the device decreases. It is furthermore particularly advantageous that no preliminary transport is necessary between the chambers. In addition, it is sufficient to only use a single gas injection/fluidization stream, which is supplied throughout the entire sieve bottom. Overall, the device can be provided in an inexpensive manner, and the method as maintenance of the device are also found to be economical.
[0009] Preferably, product passages are provided between adjacent chambers on the bottom side between the sieve bottom and a lower end area of the separating wall between adjacent chambers. Alternatively or additionally, the product passages may also be provided between adjacent chambers on the wall side between a side wall and a lateral end area of the separating wall between the adjacent chambers. Surprisingly, once this arrangement of product passages is used, very little backmixing occurs between the chambers. In addition, this arrangement makes it easier to empty of the device after use, e.g. for cleaning or maintenance purposes, or in the case of product changes.
[0010] Advisably, further product passages are provided in the separating wall at roughly the height of the upper end of the fluidized layer.
[0011] In an exemplary embodiment, the product passages extend over the entire width and/or the entire height of the device from one side wall to the other side wall and/or from the sieve bottom to the upper end of the fluidized layer, wherein the product passages are provided as horizontal and/or vertical slits. In particular, each slit-shaped product passage extends along the entire width and/or along the entire height of a separating wall. Only horizontal slits can be used as product passages to achieve a narrow range of residence times.
[0012] In another exemplary embodiment, along the separating walls that are provided successively in the direction of transportation of the product, the product passages are disposed alternatingly on the bottom and at the height of the upper end of the fluidized layer. In this manner, all product particles are forced through the device along a roller coaster-like path, and for each chamber, the product inlet is located as far as possible from the product outlet, as a result of which all particles need to travel along a relatively long path through the respective chamber. In case the product passages are always in the bottom in adjacent separating walls, for example, particles might under certain conditions travel directly from one product passage through the next one without staying in the respective chamber for a long period of time. In view of the desired narrow range of residence times in the device, this would be counterproductive. Alternatively, along the separating walls that are provided successively in the direction of transportation of the product, the product passages can also be disposed alternatingly on the left wall-side end and on the right wall-side end of the separating wall. Again, as described above, the particles are forced to travel along a slalom-like path within the device. Both the roller coaster as well as the slalom configuration contribute to keeping the residence times of the product uniform and therefore contribute, in addition to the multi-chamber configuration of the device, to a narrow range of residence times.
[0013] It is also advisable to make the position of the product passages adjustable. This makes it possible to undertake product-specific optimizations, e.g. by adjusting the average residence times of the granulate particles in the device.
[0014] In this context, it is also particularly advantageous to make it possible to adjust the cross-section of the product passages. This permits optimizations by adjusting the cross-section of the product passages depending on the granular size of the granulate.
[0015] A minimum dimension, in particular the width of the slit of the cross-section of the product passages, can be set to between a minimum dimension of the granulate and approx. 20 cm. A particularly advantageous minimum dimension, in particular the width of the slit of the cross-section of the product passages, is in the range between twice the value of the minimum granulate size and approx. ten times the value of the minimum granulate size. This also contributes to decreasing the probability that a granulate particle will travel directly through a chamber from the chamber inlet to the chamber outlet. As a result, at least very short residence times are virtually impossible. This is particularly preferable and meaningful for the crystallization of polyesters such as PET since, in case the residence time of a polyester pellet is too short, insufficient crystallization occurs, which leads to sticky pellets. A residence time that is slightly too long, however, does not negatively impact product homogeneity in the case of crystallization of polyesters since the time-dependent rise in the level of crystallization initially increases sharply and then quickly reaches a saturation level. Another advantage is that the probability of backmixing is also minimized, which additionally increases the thermal efficiency of the device, and each chamber maintains a defined temperature.
[0016] In another exemplary embodiment, each of the product passages that is disposed on the bottom side or roughly at the height of the upper end of the fluidized layer in the separating wall and/or each of product passages that is disposed on the wall side are provided with a metal sheet which runs roughly parallel to the bottom and/or the respective side wall and which runs roughly perpendicular to the separating wall, wherein such metal sheet is secured on the edge of the respective product passage and extends, through the product passage, on both sides of such separating wall into the two adjacent chambers. In this manner, a product passage is created which has the form of a type of tunnel between this metal sheet and the bottom and/or the side wall. A particle which enters this tunnel in the direction opposite the flow of the fluidized product is therefore in all likelihood reflected back and forth between the tunnel walls and therefore has a longer time of residence in the product passage, which greatly increases the probability that, sooner or later, it will be dragged along as it is collides with other particles of the fluidized product stream. As a result, this tunnel version also makes backmixing, which leads to the above-mentioned negative consequences, more difficult and, ultimately, virtually impossible.
[0017] In the area of the bottom-side product passages and essentially opposite the metal sheet, injection areas can be disposed in the sieve bottom which make it possible to inject fluidization gas into the chamber at a speed which permits both a speed component perpendicular to the injection area as well as a speed component parallel to the injection area in the direction of flow of the fluidized granulate. For that purpose, a so-called conidur metal sheet can be used in which openings are not created by completely punching out and removing material from the sieve bottom, but rather by only partially punching out and then bending the partially punched-out material. Therefore, in the area of the product passage and, in particular, in the tunnel version, in the area of the tunnel, next to the fluidization component which extends perpendicularly upwards, a horizontal transportation component can be transferred onto the product, which also renders backmixing more difficult.
[0018] If necessary, it is also possible to connect at least the first chamber via its sieve bottom with an associated supply channel for fluidization gas, which is separate from a common supply channel for the remaining chambers. This can be achieved e.g. by a common air circuit which, upstream from the sieve bottom of the first- chamber and the common sieve bottom of the remaining chambers, is provided with a branched section wherein, in each branch which is used as a supply line for the respective sieve bottom and as a draining line for the chambers, an adjustable flap is provided by means of which the gas supply and, therefore, also the gas speed can be adjusted for fluidization of the respective chambers. This makes it possible to supply gas and fluidize the first chamber under conditions that are different from those in the remaining chambers. For example, for the crystallization of polyesters, in the first chamber, a higher gas speed can be used for fluidization through the sieve bottom than in the other chambers. This is advantageous insofar as, in the product which has not yet or has hardly crystallized in the first chamber, which is far more stickier than the product in the adjacent remaining chambers, an increased gas speed can result in increased fluidization and therefore prevent the formation of agglomerates.
[0019] In most cases, however, it is sufficient to associate all chambers, via their respective sieve bottom, with a common supply channel for fluidization gas. This reduces the material cost of the device, and operation is simplified.
[0020] At the product outlet, an impact deagglomerator can be provided in which the product passage terminates. This impact deagglomerator breaks up any agglomerates which have formed in spite of all preventive measures.
[0021] The sieve bottoms of all chambers may be disposed in a single plane. Alternatively, the device may comprise chambers that are disposed along the fluidized granulate stream with staggered heights.
[0022] The layout of the first chamber can be defined by a cylindrical surrounding wall, and the remaining chambers are concentrically disposed with cylindrical walls radially on the outside of the first chamber. This construction can require particularly little space and material, and heat losses are also low. Alternatively, the layout of the first chamber can be defined by a pair of concentric, cylindrical walls, and the remaining chambers are concentrically disposed with their cylindrical walls radially inside of the inner cylindrical wall of the first chamber.
[0023] Instead of a cylindrical layout, the first chamber may also have a rectangular layout, and the remaining chambers may be disposed towards the outside of the first chamber. In addition to the aforementioned advantages of a cylindrical geometry, the rectangular shape is additionally advantageous insofar as it is particularly easy to construct. Alternatively, once again, the layouts of the first chamber can also be rectangular, and the remaining chambers are concentrically disposed inside the first chamber, e.g. nested inside each other, and may also have rectangular layouts.
[0024] All embodiments described above are particularly advantageous in case at least the remaining chambers are designed in such a manner that, in such chambers, the ratio between the layer height of the fluidized granulate and the smallest layout chamber size is in the range of 0.5 to 2. This target value for the above ratio ensures that, inside the fluidized product, no excessive formation of bubbles can occur. In case the layer height of the fluidized product is much greater than twice the smallest layout chamber size, many small bubbles may, while rising, combine to create a few or only a single big bubble which, due to the gravitational pressure, which decreases towards the top, may rise in the fluidized product and, once it reaches the surface of the fluidized layer, may cause collisions and/or cause the granulate particles to be thrown about. On the other hand, in case the bottom is only covered with a thin layer of the product, economical fluidization is not possible.
[0025] The first chamber which is located the farthest upstream can occupy a major part of the total volume of all chambers, i.e. in particular roughly half of the total volume of all chambers. It is advisable that the sieve bottom surface of the first chamber also accounts for a major part of the total sieve bottom surface of all chambers, i.e. again roughly half of the total sieve bottom surface of all chambers. This is particularly advantageous for the crystallization of polyesters. As a result, in the first chamber, in a first crystallization step, almost all particles can be largely crystallized. Considering that, during this first phase, isolated particles are still sticky, it is particularly important to achieve, in the first chamber, large-volume fluidization with a lower particle density than in the adjacent remaining chambers. In this case, the probability of collision of two sticky particles and, consequently, the formation of agglomerates is much smaller.
[0026] It is advisable to provide, on the downstream end of the last chamber, the product outlet in a wall in the form of a window and provide a slider by means of which the lower edge of the window can be adjusted. Alternatively, on the downstream end of the last chamber, the product outlet can be provided in the form of a type of pivotable gate whose height can be adjusted by pivoting the gate.
[0027] To prevent isolated granulate particles from exiting the device together with the fluidization gas which is drawn off in the roof area of the device, e.g. when larger bubbles reach the fluidized layer surface, above the fluidized layer, upstream from the vent, a so-called zigzag separator is disposed which allows the gas to pass while retaining the granulate particles and returning them to the fluidized bed.
[0028] The granulate can be conducted through the plurality of fluidization chambers that are disposed in series, wherein each such fluidization chamber has a sieve bottom through which, into the respective chamber, a fluidization gas (e.g. pure nitrogen or air) is injected for the purpose of fluidizing the granulate and, in the roof area of the device, such gas is drawn off, and the absolute filling height of the fluidized granulate in the first chamber is at least as high as the absolute filling height of the remaining chambers that are disposed downstream therefrom.
[0029] It is advisable to inject, into all chambers, fluidization gas with a uniform first treatment temperature, wherein the fluidization gas is preferably also used as a thermal source for heating the fluidized granulate. In the case of crystallization of PET, this uniform first treatment temperature is approx. 180° C. The still predominantly amorphous initial product enters the first chamber in the form of pellets at a temperature of approx. 20° C. and, at this low temperature, in a non-sticky form. In the first chamber, heat is not yet completely transferred onto the PET granulate, which, in turn, is advantageous since, in the amorphous or only slightly crystallized state, the propensity to stickiness when exposed to heat is still very high. In the adjacent chambers, the temperature of the PET granulate increases step by step, since in these chambers, the respective initial temperatures are always higher than in the preceding chambers and in each chamber, gas is injected at the same treatment temperature. As a result, an optimal crystallization process can be designed for PET wherein, from one chamber to the next, the temperature of the PET granulate develops towards the optimal crystallization temperature while, at the same time, the degree of crystallization of the PET increases from one chamber to the next and, as a result, the adhesive propensity is kept low even as the temperature increases.
[0030] If necessary, the fluidization gas may contain, at least partially, a gas which reacts with the fluidized granulate. For example, in the case of drying of food, this may be a disinfectant or aromatizing gas.
[0031] It is advisable to inject, into at least one of the remaining chambers, a fluidization gas with a second treatment temperature which can be used as a cold source to cool the fluidized granulate.
[0032] In all chambers, the fluidization gas is injected with the same overpressure and the same gas speed. If necessary, however, into the first chamber, the fluidization gas can be injected with a higher pressure and/or higher gas speed than in the remaining chambers. A higher gas speed leads to increased fluidization, i.e. expansion of the fluidized layer, whereas a higher gas pressure makes it possible to supply more heat via the fluidization gas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Further advantages, characteristics, and applications are described in the following description of a preferred embodiment herein, which refers to the attached drawing, wherein
[0034] [0034]FIG. 1 is a cross-sectional view along a vertical plane of a first sample embodiment;
[0035] [0035]FIG. 2 is a cross-sectional view along a vertical plane of a second sample embodiment;
[0036] [0036]FIGS. 3 a and 3 b are cross-sectional views along a vertical and a horizontal plane of a third sample embodiment;
[0037] [0037]FIG. 4 is a diagram which shows how the range of residence times of granulate particles in the device depends on the number of chambers of the device;
[0038] [0038]FIGS. 5 a and 5 b are schematic representations of a one-stage fluidized layer and a five-stage fluidized layer, respectively;
[0039] [0039]FIG. 5 c shows the local temperature development of the product of the fluidized layer shown in FIG. 5 a and the fluidized layer of 5 b , respectively;
[0040] [0040]FIG. 6 a is a first special design of the product passages between the chambers; and
[0041] [0041]FIG. 6 b is an enlargement of a second special design of the product passages between the chambers.
DETAILED DESCRIPTION
[0042] [0042]FIG. 1 is a schematic representation of a vertical cross-section of a first sample embodiment of the device 1 . The device 1 forms a multiple-box crystallizer with a housing 13 , in the interior of which several chambers 2 , 3 , 4 , 5 , and 6 are divided by the separating walls 14 , 15 , 16 , and/or 17 . The bottom of the chambers is provided by a sieve bottom 11 through which a fluidization gas can be supplied from below. Towards the top, the chambers are delimited by a zigzag separator 12 which forms the roof of the chamber. The front and rear walls of the chambers 2 , 3 , 4 , 5 , and 6 extend parallel above and/or below the drawing plane and are therefore not shown in the cross-sectional view.
[0043] The product to be fluidized and subjected to heat treatment, which is, in particular, polyethylene terephthalate (PET), is introduced into the device 1 via a product inlet 7 from the top and exits the device 1 via a product outlet 8 . The fluidization gas is injected via a gas inlet 9 below the sieve bottom 11 into the device 1 and is drawn off, after passing the zigzag separator 12 , via a gas outlet 10 in the roof area of the device 1 . The granulate which enters the device 1 first reaches the first chamber 2 , which accounts for a major part of the entire chamber volume, and is fluidized by the fluidization gas entering via the sieve bottom 11 , creating a fluidized layer 23 comprising the granulate and the fluidization gas. The fluidized layer performs like a fluid, i.e. within the fluidized layer, a gravitational pressure forms, and the fluidized layer flows via the product passages 18 , 19 , 20 , and 21 between a lower end area of the separating walls 14 , 15 , 16 , and/or 17 and the sieve bottom 11 from the first chamber 2 into the adjacent chambers 3 , 4 , 5 , and/or 6 . At the end of the last chamber 6 , in the end wall, a window 22 is provided at a certain height above the sieve bottom 11 , and this height defines the height of all fluidized layers 23 in all chambers 2 , 3 , 4 , 5 , and 6 . A schematic representation of the fluidized layer 23 is shown in FIG. 1.
[0044] Within the fluidized layer 23 , bubbles may form which can rise to the top within the fluidized layer and combine to form larger bubbles 24 which burst as soon as they reach the surface of the fluidized layer 26 and throw the granulate around within the chamber. This is schematically shown in the area of the reference number 25 .
[0045] [0045]FIG. 2 is a vertical cross-sectional view of a second sample embodiment of the device 1 . This second sample embodiment differs from the first sample embodiment insofar as in the separating walls 14 , 15 , 16 , and 17 which are provided in series between the chambers 2 , 3 , 4 , 5 , and 6 , the product passages 28 , 29 , 30 , and/or 31 are alternately disposed at a certain height above the sieve bottoms 11 in the separating walls 14 and 15 and directly on the sieve bottom 11 in the separating walls 15 and 17 . In this manner, the granulate particles, while traveling through the chambers 2 , 3 , 4 , 5 , and 6 , are forced onto a path which alternatively runs on top and on the bottom, similar to a roller coaster. This is advantageous insofar as in each chamber, the upstream product passage and the downstream product passage are located as far way from each other as possible. As a result, all granulate particles are forced to travel along the longest possible path through each of the chambers 2 , 3 , 4 , 5 , and 6 , as a result of which at least as few granulate particles as possible have a short residence time.
[0046] This is particularly advantageous for the crystallization of polyesters as they largely lose their stickiness after a minimum residence time in a crystallizer, whereas residence times that are too long do not adversely impact product quality. Due to the cascade-like arrangement of the product passages 28 and 30 , the volume of the fluidized layers gradually decreases from the first chamber 2 to the second and third chamber 3 , 4 and to the fourth and fifth chamber 5 , 6 . All reference numbers that are identical in FIG. 1 and FIG. 2 refer to the same or corresponding elements of the device 1 .
[0047] [0047]FIG. 3 a is a vertical cross-sectional view of a third sample embodiment of the device 1 , whereas FIG. 3 b shows a horizontal cross-sectional view of such a third sample embodiment. As is clearly shown in FIG. 3 b , the device 1 comprises a central cylindrical chamber 2 which, in turn, occupies a major part of the entire chamber volume of the device 1 , as well as peripheral chambers 3 , 4 , 5 , and 6 , which are disposed radially from the central chamber 2 and surround the same along its entire circumference. The central chamber 2 is separated by means of a separating wall 14 from the chambers 3 , 4 , 5 , and 6 which radially surround it, and the chambers 3 , 4 , 5 , and 6 , in turn, are delimited on the outside by the housing wall 13 . Between the chambers 3 , 4 , 5 , and 6 , separating walls 15 , 16 , and 17 are provided, as a result of which four chambers 3 , 4 , 5 , and 6 of equal size are created. At a certain height above the sieve bottom (FIG. 3 a ), a product passage 18 is provided to connect the first chamber 2 and the second chamber 3 . While the product passages between the chambers 3 , 4 , 5 , and 6 are not shown, they match the product passages 18 , 19 , 20 , and 21 in FIG. 1 and/or the product passages 28 , 29 , 30 , and 31 in FIG. 2.
[0048] Both in FIG. 1 and in FIG. 2 and in FIG. 3 b , the height and/or the cross-sectional dimension of the window 22 can be adjustable. By making its height adjustable, the height of the fluidized layer 23 is adjusted, while making the cross-sectional dimension adjustable makes it possible to adjust the flow rate through the device 1 . Both in the sample embodiments 1 and 2 with a rectangular geometry as well as in the sample embodiment 3 with a cylindrical geometry, the product passages can be provided on the bottom only (compare product passages 18 , 19 , 20 , and 21 in FIG. 1), or they may alternately be provided on the top and bottom, creating a roller coaster configuration (compare product passages 28 , 29 , 30 , and 21 in FIG. 2), or they may alternately be provided on the left or right end area of the series of separating walls 14 , 15 , 16 , and 17 in the area of the side wall, providing a slalom-like configuration (not shown herein).
[0049] [0049]FIGS. 1, 2 as well as 3 a and 3 b describe three different sample embodiments of the device 1 . In all three cases, they are different constructions of a five-stage fluidized layer 23 . They differ in the configuration of the chambers 2 , 3 , 4 , 5 , and 6 and of the product passages 18 , 19 , 20 , 21 ; 28 , 29 , 30 , 31 as well as the product openings 22 . Each five-stage fluidized layer comprises a large chamber 2 , the (main) crystallization chamber, and four subsequent smaller chambers 3 , 4 , 5 , 6 of equal size, where the product is homogenized. The chambers 3 , 4 , 5 , 6 are either provided in series or disposed concentrically around the larger chamber 2 . The fluidized layer apparatuses 1 are supplied by a single gas supply. As a result of the pressure drop, the gas its distributed over the sieve bottom 11 and the fluidized layer 23 throughout the individual chambers 2 , 3 , 4 , 5 , 6 . The product passages 18 , 19 , 20 , 21 ; 28 , 29 , 30 , 31 are provided on the bottom, on the top, or alternately on the bottom/top. In the sample embodiment shown in FIG. 1, since the product passages 18 , 19 , 20 , 21 are provided on the bottom, a fluidized layer 23 is created with a uniform height in the chambers 2 , 3 , 4 , 5 , 6 .
[0050] This height can be regulated via the height of the product outlet window 22 in the last chamber 6 . In the sample embodiment shown in FIG. 2, the layer height of the fluidized layer 23 can be independently adjusted in the chamber 2 , the chambers 3 and 4 , and in chambers 5 and 6 since the product passages 28 , 29 , 30 , 31 are alternately disposed on the bottom and in the top, by adjusting the height position of the top product passages 28 , 30 .
[0051] [0051]FIG. 4 shows the dimensionless range of residence times of n ideally mixed, fluidized chambers and/or tank reactors (tank reactor cascade) that are connected in series. The calculation is based on the assumption that the average residence time of the product in the individual fluidized chambers and/or tank reactors is the same. Please note that as the number of fluidized chambers and/or tank reactors increases, the range of residence times decreases and, consequently, the homogeneity of the thermally treated product increases at the outlet of the apparatus. In case an endless number of fluidized chambers and/or tank reactors is used, a pure plug flow is obtained. In this case, all particles are exposed to the effects occurring in the individual chambers and/or reactors for the same period of time, and the quality of the product that is obtained is very homogeneous. In practice, it is often sufficient to divide the apparatus into a few chambers to obtain an improved and sufficiently high product quality.
[0052] [0052]FIGS. 5 a and 5 b are schematic representations of a single-stage and a five-stage fluidized layer. FIG. 5 c shows, as the result of a sample calculation, the local development of the product temperature both in this single-stage as well as this five-stage fluidized layer. In this example, the local product temperature development (temperature distribution) of the five-stage fluidized layer was compared with the local product temperature development (temperature distribution) of the single-stage fluidized layer. The product throughput and the operating parameters are representative for industrial facilities that are being constructed today. Please note that the crystallization heat that is released was included in the thermal balance of the first chamber (where a large part of the exothermal crystallization reaction occurs). It is apparent that, by dividing the fluidized layer into several stages/chambers, the heat exchange efficiency between the gas and the granulate can be significantly improved while, at the same time, the quality and homogeneity of the final product is also improved. In this example, it was possible to increase the thermal efficiency (defined and measured as the ratio between [product temperature at the product outlet-product temperature at the product inlet]/[treatment temperature at the gas inlet-product temperature at the product inlet]) by approx. 7.5%. As a result of a higher product temperature after crystallization, during a process step, which is usually carried out subsequently thereto, involving subsequent condensation of the solid phase (SSP), the size of the apparatus which is required therefor can be reduced.
[0053] Conclusion: the multi-stage fluidized layer can both provide an improved, e.g. narrower, range of residence times of the product in this multi-stage fluidized layer as well as an improved, i.e. increased, thermal efficiency of the thermal treatment of the product.
[0054] [0054]FIGS. 6 a and 6 b show a particularly advantageous first embodiment of the product passages between the chambers of the device.
[0055] [0055]FIG. 6 a corresponds to a section of FIG. 1 showing the separating walls 14 , 15 , 16 , and 17 in their lower section in the proximity of the sieve bottom 11 . The sieve bottom 11 has holes 11 a which were created by punching out and removing material. Other than in FIG. 1, however, the lower end of the separating walls 14 , 15 , 16 , and 17 has been provided with a guide sheet 33 , 34 , 35 , and/or 36 which extends, on both sides of the corresponding separating wall and perpendicularly thereto, into the chambers on both sides of the respective separating wall. The guide sheets 33 , 34 , 35 , 36 make backmixing, e.g. a migration of the granulate particles backwards against the flow of granulate, more difficult. Backmixing reduces the thermal efficiency and widens the range of residence times on the side where longer residence times exist. The tunnel-shaped product passages 18 , 19 , 20 , 21 that are formed thereby make it unlikely for a granulate particle to travel against the direction of flow of the fluidized granulate from one chamber back into a chamber located upstream therefrom since, in all likelihood, such a particle will be reflected back and forth between the sieve bottom 11 and the corresponding guide sheet 33 , 34 , 35 , 36 and must remain in this tunnel for a while, as a result of which, ultimately, in all likelihood, it is dragged along through collisions with granulate particles drifting in the direction of flow of the granulate.
[0056] [0056]FIG. 6 b shows a second embodiment of the product passages 18 , 19 , 20 , 21 which has been improved compared with the first embodiment shown in FIG. 6 a . The section of FIG. 6 b matches the circled section of the first embodiment of the product passages in FIG. 6 a , except that in this case, in the area of the tunnel opposite the corresponding guide sheet 33 , 34 , 35 , 36 , the sieve bottom 11 is provided with holes 11 b created by only partially punching out material and bending such partially punched-out material. Through these holes 11 b , the air that is drawn in receives, in addition to its vertical fluidization component perpendicular to the direction of flow of the granulate, a motion component parallel to and aligned with the direction of flow of the granulate. As a result, backmixing becomes even more improbable than in the embodiment of FIG. 6 a.
[0057] Conclusion: the two embodiments of the product passages 18 , 19 , 20 , 21 of FIGS. 6 a and 6 b can contribute to further improving the thermal efficiency and narrowing the range of residence times of the device 1 .
[0058] It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
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The invention relates to a device for continuous heat treatment of granulated materials, especially to the crystallization of polymer granulate, such as polyethyleneterephthalate (PET) for example. The device comprises several adjacent fluidization chambers respectively provided with a sieve plate through which a fluidization gas used to fluidize the granulate can be insufflated into the respective chamber from below via a gas inlet, the gas being able to escape via a gas outlet in the top area of the device. The first chamber takes up the greater part of the overall volume of all chambers and neighboring chambers are, respectively, fluidically connected by product throughflow openings in the separating walls arranged therebetween. The granulated material can be guided through several adjacent fluidization chambers, the absolute filling level of the fluidized granulating material in the first chamber being at least as high as the absolute filling level of the other adjacent chambers disposed downstream therefrom.
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BACKGROUND
Embodiments of the present invention relate generally to new and useful improvements in mobile aircraft recovery, and more particularly to an apparatus and method for the capture of aircraft, including unmanned aerial vehicles (UAVs), drones, and other flight devices or projectiles.
The recovery of aircraft without the use of a runway is generally known in the art. See, for example, the “skyhook” approach, as disclosed in U.S. Pat. Nos. 7,090,166, 7,104,495, 7,114,680 and Pre-Grant Publication Nos. 2005/0151009 and 2005/0178894, where a boom from a ship or other vehicle is extendable to deploy a recovery line to capture the aircraft in flight. The skyhook approach requires that the leading edge of the aircraft wing be strong enough to survive the wire impact on the recovery line. Thus, the aircraft structure is heavy, resulting in a negative impact on aircraft payload capacity and endurance. Other approaches, such as the arresting hook in U.S. Pat. No. 7,143,976 to Snediker et al., or the deployable lifting device in U.S. Pat. No. 4,753,400 to Reuter et al., share similar problems.
In short, there exists a need in the art for a mobile aircraft recovery system that is able to limit damage to the aircraft during recovery using a lighter aircraft and, thus, minimizing, the impact on aircraft endurance. A further need exists for a mobile aircraft recovery system that is itself small and lightweight so as to be mobile, versatile on land and sea, and transportable. Additionally, a need exists for a mobile aircraft recovery system having a strong wind tolerance, including tolerance of wind variation, direction and speed.
SUMMARY
In an embodiment, an apparatus for the recovery of an aircraft includes a capture device and a first and second pole pair. The first pole pair includes first top and bottom poles respectively placed near first top and bottom portions of the capture device. The first pole pair is configured to move from a first position, in which the pole pair holds the capture device in an open position to capture the aircraft, to a second position, in which the pole pair holds the capture device in a closed position to contain the captured aircraft after impact of the aircraft on the capture device. The second pole pair includes second top and bottom poles respectively placed near second top and bottom portions of the capture device. The second pole pair is also configured to move from the first position to the second position. The apparatus further includes energy elements each coupled on one end to a respective top or bottom portion of the capture device and on another end to a respective top or bottom pole. The energy elements are disposed to absorb the force of the impact.
According to one exemplary embodiment, the first pole pair comprising first top and bottom poles may be coupled at first ends to a first support beam, the top and bottom poles extending to first top and bottom portions of the capture device. Similarly, the second pole pair comprising second top and bottom poles may be coupled at first ends to a second support beam, the top and bottom poles extending to second top and bottom portions of the capture device. Further, a pivot beam may be coupled to each of the first and second support beams, wherein the pivot beam is disposed to pivot each of the first and second support beams forward in the direction of the impact of the aircraft.
In another embodiment, a method for the recovery of an aircraft includes coupling a first pole pair comprising first top and bottom poles respectively to first top and bottom positions of a capture device and coupling a second pole pair comprising second top and bottom poles respectively to second top and bottom positions of the capture device. The method further includes moving each pole pair from a first position, in which the pole pairs hold the capture device in an open position to capture the aircraft, to a second position, in which the pole pairs hold the capture device in a closed position to contain the captured aircraft. The method includes absorbing he force of the impact using energy elements, each coupled on one end to a respective top or bottom position of the capture device and on another end to a respective top or bottom pole.
According to a further embodiment, the method includes pivoting the first and second pole pairs forward in the direction of the impact.
This summary is provided merely to introduce certain concepts and not to identify any key or essential features of the claimed subject matter. Further features and advantages of embodiments of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features and advantages of embodiments of the invention will be apparent from the following, more particular description of embodiments of the invention, as illustrated in the accompanying drawings wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. Unless otherwise indicated, the accompanying drawing figures are not to scale.
FIG. 1 depicts a perspective view of the mobile aircraft recovery system according to an embodiment of the present invention;
FIG. 1A depicts a rear detailed view of the shock absorption device of the mobile aircraft recovery system, as shown in FIG. 1
FIGS. 2A and 2B depict a detailed view of the tear straps of the mobile aircraft recovery system as shown in FIG. 1 ;
FIG. 3A depicts a side view of the mobile aircraft recovery system prior to impact of the aircraft, according to an embodiment of the present invention;
FIG. 3B depicts a side view of the mobile aircraft recovery system during impact of the aircraft, according to an embodiment of the present invention;
FIG. 3C depicts a side view of the mobile aircraft recovery system after impact of the aircraft, according to an embodiment of the present invention;
FIG. 4 depicts a side view of the mobile aircraft recovery system during impact of the aircraft, according to an alternative embodiment of the present invention
FIGS. 5 and 6 depict an exploded view of the mobile recovery unit in a stowed position, according to an embodiment of the present invention; and
FIG. 7 depicts a front view of a control unit of the mobile aircraft recovery system, according to an embodiment of the present invention.
DETAILED DESCRIPTION
Various embodiments of the invention are discussed herein. While specific embodiments are discussed, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected and it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations can be used without parting from the spirit and scope of the invention. Each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.
Referring now to the drawings, there is shown in FIG. 1 a perspective view of the mobile aircraft recovery system 100 according to an embodiment of the present invention. A capture device 102 , for example, a net, sits in an open vertical position above the ground prior to the capture of an aircraft. The vertical position of the net 102 may be referred to as a “ready to capture position.” The net 102 is shaped to focus the deceleration loads on the aircraft wing closest to the fuselage, thus avoiding wing tip bending. For example, according to one embodiment, the net 102 may be a ribbon net or other net which forms a basket shape, expanding outward to cradle the aircraft during capture. The use of a basket-shaped net retains the aircraft after impact and prevents the aircraft from falling out of the net or springing backwards off the net 102 and incurring damage.
The net 102 is supported, for example, by two pole pairs 104 . The pole pairs 104 of the mobile aircraft recovery system 100 are used to absorb the momentum of the aircraft during capture. Each pole pair 104 may include an upper net pole 104 ′ coupled to an upper portion of the net 102 and a lower net pole 104 ″ coupled to a bottom portion of the net 102 . In the embodiment shown, the poles 104 ′, 104 ″ are coupled to corners of the net 102 . Each net pole 104 ′, 104 ″ may rotate about a pivot point located at an opposite end of the respective net pole 104 ′, 104 ″ from the net 102 . Further, the upper and lower net poles 104 ′, 104 ″ of each pole pair 104 may move in synchronization relative to one another.
The initial impact of the aircraft on the net 102 engages the pivoting movement of the pole pairs 104 . A timing or kinematic mechanism may be coupled to each pole pair 104 to help synchronize the movement of the top and bottom net poles 104 ′, 104 ″ together. Such synchronization allows the net 102 and pole pairs 104 capture an aircraft 300 (see FIG. 3A ) by folding around the primary aircraft wing to decelerate the aircraft while engulfing the aircraft for post deceleration retention.
According to one embodiment, the net 102 and pole pairs 104 may be coupled using energy elements 106 , i.e. tear straps. The tear straps 106 may be positioned on the corners, or other positions, of the net 102 to improve capture geometry and to reduce the initial structural shock impulse, i.e. to attenuate the initial peal load. As seen in FIG. 2A , the tear straps 106 may be positioned between ropes or lanyards 108 holding the corners of the net 102 and the ends of each net pole 104 ′, 104 ″. Prior to capture, the tear straps 106 are embodied in a retracted position 106 ′ and, for example, may comprise Nylon, or other material, doubled-over straps sewn together down the center of the strap with a thin sewing thread. In the retracted position 106 ′, the tear straps 106 may provide additional slack to the net 102 to attenuate the impact force as the aircraft wings initially hit the net 102 .
Following the impact of the aircraft 300 on the net 102 , the tear straps 106 may shift from the retracted position 106 ′ into a released position 106 ″, as shown in FIG. 2B . This may occur, for example, when the sewing thread of the tear strap 106 registers a certain force, for example, a force of approximately 50 lbs, that is associated with the impact of the aircraft on the net 102 , and breaks; ripping the seam holding the tear strap 106 in the retracted position 106 ′. Thus, the breaking of the sewing thread allows the force of the impact to pull the tear strap 106 in retracted position 106 ′ fully or partially straight into the released position 106 ″, as seen in FIG. 2B . This causes the tear straps 106 to change the angle of the net to improve capture of the aircraft. As the straps tear they smoothly accelerate the pivot arms thus avoiding a rapid acceleration similar to an impact that would occur without these devices. Alternatively, other energy elements may be used, such as, for example, slip devices, Velcro® or shock absorbers. After use, the energy elements may either be reused or replaced.
According to the embodiment shown in FIG. 1 , the pole pairs 104 are held in place by two hydraulically erectable arm assemblies 110 joined to a central shaft, called the recovery pivot beam 112 . Each arm assembly 110 includes a vertical beam 114 , a corner beam 116 and a diagonal beam 118 . On one end of the arm assembly 110 , the vertical beam 114 is coupled to the pole pair 104 . On the other end of the arm assembly 110 , the diagonal beam 118 is connected to the recovery pivot beam 112 . The corner beam 116 serves to connect the vertical beam 114 to the diagonal beam 118 .
According to one embodiment, the mobile aircraft recovery system 100 may include one or more shear devices 120 , such as a shear pins, nylon ties, or the like, which hold the net in the ready to capture position prior to recovery. Specifically, the shear devices 120 maintain an open net 102 by holding the lower net pole 104 ″ in a certain position relative to the arm assembly 110 . This prevents the pole pairs 104 from prematurely pivoting, for example, due to wind or other external forces. When a certain force that is associated with the impact of the aircraft on the net 102 is registered by the shear device 120 , the shear devices 120 release allowing the pole pairs 104 to gain their initial momentum forward. The shear devices 120 may be replaced after each recovery.
According to another embodiment, the mobile aircraft recovery system 100 may include one or more shock absorption devices 122 positioned to absorb energy upon impact of the aircraft 300 . As shown in FIG. 1 , the shock absorption devices 122 may be coupled to the top of vertical beam 114 . The shock absorption devices 122 may also be coupled to the pole pairs 104 and may provide the pivot point for each pole pair 104 . The shock absorption devices 122 may be, for example, friction dampers or brakes, rotary shock absorbers or dampers, or linear dampers. Such shock absorption devices 122 may help slow the aircraft and bring the aircraft to rest in the net. The pivot of the whole structure of the mobile aircraft recovery system 100 helps keep the aircraft from swinging.
FIG. 1A depicts a rear detailed view of a shock absorption device 122 , as shown in FIG. 1 . According to one embodiment, the shock absorption device 122 includes a vertical bar 125 which may be coupled to the vertical beam 114 of the arm assembly 110 . A sliding mechanism 127 may be coupled to the vertical bar 125 to control the pivoting movement of the pole pair 104 . Coupled to the sliding mechanism 127 are two dampers 123 to absorb the shock of the impact of the aircraft in the net 102 . As described above, the dampers 123 may be friction, rotary or linear dampers. Pole levers 124 may be further coupled to each end of the sliding mechanism 127 and are able to attach to the ends of the top and bottom net poles 104 ′, 104 ″.
According to a further embodiment, each shock absorption device 122 may include the timing or kinematic mechanism which, as previously discussed, facilitates the synchronous movement of the top and bottom net poles 104 ′, 104 ″. The timing mechanism enables the pole levers 124 of the top and bottom net poles 104 ′, 104 ″ to move at the same time. The synchronous movement of the pole pairs 104 , when combined with the energy elements 106 , forms the net 102 into a basket configuration which cradles the aircraft upon impact. Non-synchronous movement of the pole pairs 104 may cause the net 102 to remain in the flat ready to capture position, causing the aircraft to fall or bounce out of the net 102 .
According to a further embodiment, the mobile aircraft recovery system 100 includes a hydraulic activation system 126 , including the recovery pivot beam 112 , a recovery actuator 128 and a recovery base 130 , for raising and lowering the arm assemblies 110 and net 102 . The hydraulic activation system 126 may also include a hydraulic cushion (not shown). For example, the hydraulic cushion may include hydraulic valves and gas accumulators that are separate from the raising and lowering actuation function that permits the actuator to move passively in the direction of recovery. The motion is permitted because the valves cause oil holding the actuator in the upright position to flow into the gas accumulator.
According to one embodiment, the recovery pivot beam 112 of the hydraulic activation system 126 allows the diagonal beams 118 of the arm assemblies 110 to fall or pivot forward during the capture of the aircraft to further help dissipate the momentum of the aircraft. This is shown in FIG. 4 , which depicts a side view of the mobile aircraft recovery system during impact of the aircraft. Angle α shows the change in position of the diagonal beam 118 forward from a starting position along axis A (see FIG. 3A ), that is perpendicular to the ground.
FIG. 3A depicts a side view of the mobile aircraft recovery system 100 prior to impact of the aircraft 300 , according to an embodiment of the present invention. The vertical beam 114 of the arm assembly 110 is positioned along a perpendicular axis A relative to the ground. Prior to impact of the aircraft 300 , the top net poles 104 ′ are positioned at a pre-determined angle θ 1 relative to axis A and the bottom net poles 104 ″ are positioned at a predetermined angle θ 11 relative to axis A. The predetermined angles θ 1 and θ 11 of the net poles 104 ′, 104 ″ are selected to ensure that the net 102 remains in the ready to capture position prior to impact. According to one embodiment, angle θ 1 is approximately equal to angle θ 11 . According to another embodiment, angles θ 1 and θ 11 of the net poles 104 ′, 104 ″ are both less than 45 degrees. Further, the tear strips 106 remain in their initial retracted position 106 ′, which aids in pulling the net 102 close to each of the top and bottom net poles 104 ′, 104 ″ and in ready to capture position.
As discussed above, shear devices 120 may be used maintain the angles θ 11 between the bottom net poles 104 ″ and the vertical beam 114 prior to impact. Because each bottom net pole 104 ″ moves in synchronization with its respective top net pole 104 ′, maintaining the angle θ 11 of the bottom net pole 104 ″ using a shear device 120 simultaneously maintains the angle θ 1 of the top net pole 104 ′. The shear devices 120 prevent wind or any other external force from inadvertently interfering with the recovery of the aircraft 300 .
FIG. 3B depicts a side view of the mobile aircraft recovery system 100 during impact of the aircraft 300 , according to an embodiment of the present invention. As the aircraft 300 strikes the net 102 , the force of impact releases the shear device 120 and causes the pole pairs 104 to each pivot about their pivot points forward in the direction of impact D. The pivoting momentum of the pole pairs 104 , allows the net 102 to form a basket-like configuration to envelop and capture the aircraft 300 . The energy absorbing devices 122 , i.e. the dampers, attached to the pole pairs 104 help bring the aircraft 300 to rest in the net 102 .
As the pole pairs 104 pivot forward the angles θ 1 and θ 11 of the top and bottom net poles 104 ′, 104 ″, respectively, increase to angles θ 2 and θ 22 relative to the perpendicular axis A defined by the vertical beam 114 of the arm assembly 110 . According to one embodiment, the angle θ 2 of the top net pole 104 ′ increases more than the angle θ 22 of the bottom net pole 104 ″ during capture.
Furthermore, the impact of the aircraft 300 on the net 102 , as well as the pivoting motion of the pole pairs 104 , causes the tear straps 106 to pull from the retracted position 106 ′ into the released position 106 ″. The release of the tear straps 106 , i.e. the straightening out of the retracted position 106 ′, may occur in the direction N of the net 102 (See FIG. 2B ). The release of the tear straps 106 may also transform the net 102 from the ready to capture position, as depicted in FIG. 3A , into the basket-like configuration, as depicted in FIG. 3B .
According to one embodiment, the top net poles 104 ′ are loaded similarly to the bottom net poles 104 ″, however the tear straps 106 are rated lower and are longer on the top than on the bottom. This ensures to improve the basket-like configuration of the net 102 . The top tear straps 106 may tear all the way and, since they are longer, they compensate for the top poles being higher.
After recovery, the pole pairs 104 and net 102 are lowered using the hydraulic actuator 128 and the aircraft 300 may be manually removed from the net by a ground crew.
FIG. 3C depicts a side view of the mobile aircraft recovery system 100 after impact of the aircraft 300 , according to an embodiment of the present invention. In this embodiment, the aircraft 300 has been captured and has come to rest in the net 102 . The top and bottom net poles 104 ′, 104 ″ have similarly come to rest at angles θ 3 and θ 33 , respectively, relative to the vertical beam 114 .
FIG. 4 depicts a side view of the mobile aircraft recovery system 100 during impact of the aircraft 300 , according to an alternative embodiment of the present invention. In addition to that described in FIG. 3B , in this alternative embodiment, as the aircraft 300 first strikes the net 102 , this initial impact force causes each arm assembly 110 to pivot forward on the recovery pivot beam 112 (see FIG. 1 ). As seen in FIG. 4 , the arm assembly 110 has pivoted away from the perpendicular axis A in the direction of impact D by an angle α. This additional movement of the arm assemblies 100 helps further dissipate the momentum of the aircraft 300 during capture.
FIGS. 5 and 6 depict an exploded view of the mobile aircraft recovery unit 100 in a stowed position, according to an embodiment of the present invention. As shown, the mobile aircraft recovery unit 100 comprises a modular design to permit disassembly for compact storage when not in use. Specifically, the recovery base 130 may house the disassembled net poles 104 ′, 104 ″, the recovery pilot beam 112 , the vertical beams 114 , the corner beams 116 , the diagonal beams 118 and the recovery actuator 128 . The recovery base 130 may fit into a mobile unit 500 , for example a trailer assembly. According to one embodiment, a launcher assembly 502 may be coupled to the recovery base 130 of the mobile unit 500 to launch the aircraft 300 .
Additionally, the net 102 , tear straps 106 , hand control unit (see control unit 700 below), electrical cables and other equipment may be transported within the mobile unit 500 in transit cases (not shown).
FIG. 7 depicts a front view of a control unit 700 of the mobile aircraft recovery system 100 , according to an exemplary embodiment of the present invention. According to one embodiment, the control unit 700 may control both the mobile aircraft recovery system 100 , as well as the launch system. The control unit 700 may include a mode switch 702 to switch between “off,” “standby,” “launch,” and “net” modes. The control unit 700 may include a net position switch 704 for lifting or lowering the position of the net 102 using the hydraulic activation system 126 . Further, the control unit 700 may include a net cushion switch 706 for adjusting the pre-determined angle α of the arm assembly 110 relative to the perpendicular axis A to ensure that the net 102 remains in the ready to capture position prior to impact of the aircraft 300 on the net 102 .
The control unit 700 may include one or more indicators 708 to indicate, for example, that the mobile aircraft recovery system 100 or launch assembly 502 is safe to operate, that the hydraulic activation system 126 of the mobile aircraft recovery system 100 is ready to pressurize, or that the launch assembly 502 is ready to launch the aircraft 300 . The control unit 700 may further include, for example, a hydraulic power unit (HPU) switch 710 to activate the hydraulic activation system 126 for either recovery operation or launch, a pressurize switch 712 to pressurize the hydraulic activation system 126 and/or a launch switch 714 to launch the aircraft using the launch assembly 502 .
Alternatively, the mobile aircraft recovery system 100 may be embodied as a passive capture system, where no electronics or computers are required. For example, switch logic may be used without the use of computers or software.
Embodiments of the mobile aircraft recovery system 100 enjoy several advantages over other systems known in the art. The mobile aircraft recovery system 100 can be mobilized on land or on a ship deck with a single trailer and does not require the use of separate supporting structures or anchors. One exception is the use of the mobile aircraft recovery system 100 on a ship deck during a high sea state, where tie-downs are required for all deck equipment. The small footprint of the mobile aircraft recovery system 100 allows for easy ship integration, including minimal modification and interference with current operations, also known as normal operations on the flight deck or “OPS.” Because the mobile aircraft recovery system 100 may be added to an existing ship, it is important that the system does not interfere with existing operational procedure and business. The mobile aircraft recovery system 100 is further able to withstand ship motion having pitch, heave and roll tolerance, as well as navigation sensitivity.
The mobile aircraft recovery system 100 is quick and easy to both assemble and disassemble. The mobile aircraft recovery system 100 does not require a unique configuration of the aircraft 300 due to the basket-like configuration of the net 102 which supports a soft impact on the aircraft wings. For example, the aircraft 300 does not require the use of strengthening devices in the aircraft's wings to support the capture, as is known in the prior art. Similarly the soft landing enabled by the mobile aircraft recovery system 100 has a minimal impact on the aircraft 300 weight since flight loads are the driving consideration for structural sizing. Only minor wing leading edge enhancement may be required with minimal weigh impact on the aircraft.
The mobile aircraft recovery system 100 may be sized to work accurately with existing aircraft navigation systems and may be combined with a launcher assembly 502 , as described above. The mobile aircraft recovery system 100 is both compact and transportable, as well as reliable and durable during use. The mobile aircraft recovery system 100 is cost efficient in both the development and production stages.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and that the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
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An apparatus for the recovery of an aircraft includes a capture device and first and second pole pairs. The first pole pair includes first top and bottom poles respectively placed near first top and bottom portions of the capture device. The first pole pair is configured to move from a first position, in which the pole pair holds the capture device in an open position to capture the aircraft, to a second position, in which the pole pair holds the capture device in a closed position to contain the captured aircraft after impact of the aircraft on the capture device. The second pole pair includes second top and bottom poles respectively placed near second top and bottom portions of the capture device. The second pole pair is also configured to move from the first position to the second position. Further, energy elements are coupled on one end to a respective top or bottom portion of the capture device and on another end to a respective top or bottom pole. The energy elements are disposed to absorb the force of the impact of the aircraft.
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FIELD OF THE INVENTION
This present invention relates generally to chemical apparatus and more specifically to a liquid mercury electrode contained within a semipermeable membrane for electrolytically analyzing or testing solutions of interest by, for example, voltammetry.
BACKGROUND OF THE INVENTION
Voltammetry is a group of techniques involving very accurate measurements of current flow as a function of potential (voltage) over a period of time. Usually the potential of the working electrode is controlled to precisely known values (which may vary in a controlled manner as a function of time) with respect to a reference electrode placed in a solution to be analyzed. Any electroactive substance in the solution will transfer electrons to (anodic oxidation), or accept electrons from (cathodic reduction), the external circuit at the active surface of the working electrode whenever the potential is in a characteristic range. The magnitude of the current is proportional to the concentration of the substance in solution and the characteristic potential depends on the identity of the substance; thus voltammetry can be used for both quantitative and qualitative electrochemical analysis.
Voltammetry is often carried out with a three-electrode configuration in an electrochemical cell containing electrolyte solutions, which may be purely aqueous, nonaqueous or mixtures of water and a solvent. A potentiostat is employed to accurately control the potential of a working electrode with respect to a reference electrode by forcing the necessary current through an auxiliary electrode. This current also passes through the working electrode and is measured using any known current to voltage transducer. Sometimes the control potential, also called the applied potential, is varied over time according to a predetermined program, for example to analyze multiple species in the sample.
Liquid mercury as an electrode material in electrochemical research is widely accepted because of its good physical and electrical characteristics. It has a wide liquid temperature range (-38.9° TO 356.9° C.) and electrodes of various shapes can be easily prepared. In contrast to solid electrode materials, the active surface of such electrodes is highly uniform and easily reproducible if the mercury is clean. Most importantly, mercury also has a very high overvoltage for hydrogen evolution relative to other metallic and carbon electrodes so that electrochemical reactions that require more negative potentials can be carried out without as much background interference.
Several types of apparatus utilizing liquid mercury electrodes have been developed since their invention circa 1922 to help simplify or improve electrochemical investigations. Among those which are well known to those skilled in this art are: dropping mercury electrodes (DME), hanging mercury drop electrodes (HMDE), static mercury drop electrodes (SMDE), streaming mercury electrodes (SME), mercury film electrodes (MFE), and, more recently, controlled growth mercury electrodes (CGME). See, for example, U.S. Pat. No. 4,548,679 (Guidelli et al) which discloses apparatus for the automatic control of the growth or size of a hanging mercury drop; U.S. Pat. No. 4,661,210 (Tenygl) which discloses methods and apparatus for electrochemical analysis of solutions by voltammetry using a pulsating liquid mercury electrode and solution within a small volume capillary tube; U.S. Pat. No. 4,846,955 (Osteryoung et at) which also relates to the control of growth or size of a mercury drop electrode; U.S. Pat. No. 5,131,999 (Gunasingham) discloses a flow cell using a renewable mercury electrode; U.S. Pat. No. 5,292,423 (Wang) which relates to methods and apparatus for trace metal testing using mercury coated, screen-printed flat film electrodes; U.S. Pat. No. 5,326,451 (Ekechukwu) which discloses a liquid dropping electrode not made of mercury for use in non-polar solutions; and U.S. Pat. No. 5,378,343 (Kounaves et al) also disclosing mercury coated flat film electrodes.
However, these prior art devices have a number of disadvantages when used to determine trace amounts of analytes, drugs or poisons, in samples of complex biological fluids, such as blood, urine, tissue homogenates, or in environmental samples.
One application of increasing importance is the determination of heavy metals (e.g. lead) in biological samples (e.g. blood). Currently, the most widely used analytical techniques are atomic absorption and inductively coupled plasma spectroscopy but, due to the advanced nature of these methods, highly trained personnel and expensive equipment is required. Scientists would like to use anodic stripping voltammetry for this purpose wherein the metal ions present in the sample would be electroplated onto a mercury electrode and subsequently removed (stripped) electrochemically. The current recorded during stripping is proportional to the concentration of the metal of interest. This method would be highly sensitive to many metal ions and could be operated at much lower cost than the commonly used methods. Potentiometric Stripping Analysis is another variation on this same theme which would be useful with improved electrodes.
Although Mercury Drop Electrodes provide a means for continuously renewing the electrode surface by releasing a used drop and forming a new one, it is still directly in contact with the sample media and hence electrode contamination or fouling from common biological components in the sample is a significant problem. Also, all mercury drop techniques introduce used mercury drops into the sample container during the analysis which contaminates the sample and makes recovery of the mercury, for proper disposal as a health hazard, or further use of the sample, which may be quite precious, difficult at best. Apart from this, currently available designs of mercury drop electrodes do not allow use of very small, microliter, volume samples which are usually the amounts available in biological research.
Routine use of a mercury electrode could be substantially increased if one could be incorporated into a flow cell arrangement, i.e. to analyze a flowing stream of analyte solution, such as in liquid chromatographic detection of reducible organic compounds. However, the stability of a mercury drop in a flow cell is greatly reduced and consequently the background electrical noise in the analytical signal is so high that the accurately processing of the data is jeopardized. The detection limit achievable in a particular analysis under these conditions is unavoidably high and hence the quality of analytical data becomes unsatisfactory.
Mercury Film Electrodes can, on the other hand, be easily incorporated into a flow cell but their stability, and therefore data reproducibility, is dependent on the adhesion of the mercury film to the substrate material. In addition, MFEs on different substrates perform differently based on the substrate surface characteristics, thereby questioning the integrity of the analysis. Metallic substrates provide better adhesion than carbon surfaces but the solubility of the solid surface in the mercury discourages long term use. For example, mercury plated onto a gold surface will slowly dissolve the gold so that after a time, the active electrode surface becomes a gold/mercury amalgam with different electrical characteristics. The useful lifetime of a film electrode depends on the type of base metal, the amount of mercury plated and its operating conditions. In the case of a carbon base surface, there is no alloying interaction that changes the nature of the mercury but the porosity of the surface affects some applications and the cleaning of the surface or recovery of metals deposited on the electrode during anodic stripping voltammetry can be difficult if not impossible. Further, mercury films, especially on carbon substrates, which are subject to flowing streams of analyte can change surface area continuously, due to loss of mercury, thereby degrading the confidence and reproducibility of the analytical data.
Mercury Film Electrodes have been coated with various polymeric materials in order to try to circumvent the fouling problems by partially filtering the unwanted electroactive and surface active species but the reproduction of a particular coating thickness, which is necessary to maintain a constant performance level from time to time, is inherently very difficult.
It is therefore a general object of the present invention to provide a new and improved method and apparatus for forming a liquid mercury electrode and in particular an electrode having a small, renewable active analyzing surface, which is protected from fouling, usable in stationary or flowing analytical solutions and without contaminating such solutions with used mercury.
SUMMARY OF THE INVENTION
The present invention aims to overcome some of the disadvantages of the prior art as well as offer certain other advantages by teaching a novel method of making and using a mercury electrode assembly having a renewable analyzing surface resistant to contamination or fouling. Basically, the assembly comprises a cylindrical liquid mercury thread, preferably of micrometer diameter and of any desired length, which is delivered to and movable through a short fixed length of thin walled tubular semipermeable membrane so that the electrode's active (analyzing) surface is protected from fouling or contamination and can be easily renewed whenever desired by advancing the mercury thread through the tubular membrane. The active surface can be inserted into stationary or flowing electrochemical cells and used as the working electrode, along with reference and auxiliary electrodes, for analysis of solutions of interest or may be even inserted directly into a living organism for real time determination of both the presence and quantity of analytes constituted in complex biological fluids in vivo.
In the present invention, semipermeable membrane means any material which is permeable to the ions of interest but not significantly permeable to larger contaminates, such as proteins, or other organic molecules, and, of course, the liquid mercury. Several suitable polymeric films are known in the art and widely used for other purposes, such as hydrophilic dialysis. One example used in the apparatus described below is regenerated cellulose.
BRIEF DESCRIPTION OF THE DRAWINGS
While this specification concludes with claims particularly pointing out and the subject matter which is now regarded as the invention, it is believed that the broader aspects of the invention, as well as several of the features and advantages thereof, may be better understood by reference to the following detailed description of a presently preferred embodiment of the invention when taken in connection with the accompanying drawings in which:
FIG. 1 illustrates the arrangement of apparatus in a simple electrochemical cell having a dip type mercury thread working electrode embodying the present invention;
FIG. 2 is an enlarged cross sectional view of the working electrode's active surface region in the apparatus of FIG. 1;
FIG. 3 illustrates the arrangement of a mercury thread electrode embodying the present invention in a typical flow cell apparatus; and
FIG. 4 is an enlarged cross sectional view of the active electrode surface region of the apparatus of FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings and particularly to FIG. 1, there is shown one embodiment of the present invention in which a simple electrochemical cell (10) is formed by a liquid container (11), in this case a glass beaker, to hold the solution (22) to be analyzed and three electrodes; a Ag/AgCl reference electrode (12), a platinum wire auxiliary electrode (13) and a working electrode assembly (15). Since the construction of, and ancillary electrical circuitry for using, reference electrodes and auxiliary electrodes are well known in the art, they will not be discussed in detail here.
The working electrode assembly (15) consists of a means for supplying a movable thread of fresh mercury (17), which in this case is a plastic syringe (16) but could be any type of reservoir and pump, a means for providing an electrical connection to the mercury thread, here a metal needle (14) in the syringe (16), a length of inert tubing (21) connected to the needle (14) to convey the mercury into the container and to the active surface region (20), described later, and then out of the cell (10) through a length of exit tubing (23). Used mercury (18) may be collected in a reservoir (19) for recycling. Preferably, a syringe pump (not shown), well known in the art, is used to move the syringe and advance the mercury since it may be accurately controlled by a digital stepping motor in an automated analysis system.
The active surface region (20) of the working electrode assembly (15), shown more clearly in FIG. 2, is formed by a short, fixed length of thin walled tubular semipermeable membrane (25) fixed between the inlet tube (21) and the outlet tube (23). The membrane (25) is firmly attached and sealed to the tubing (21, 23) by glue or cement (26). Preferably, the tubing is also glued (27) to a support (28), in this case a plastic tube, in order to provide some protection and rigidity to the joints. In use, the liquid mercury thread within the semi-permeable membrane (25) will function as the working electrode's active surface and any electroactive species in the solution (22) which is small enough to diffuse through the membrane's "micropores" can be analyzed. Whenever the active surface becomes fouled or contaminated, the mercury thread can be advanced through the membrane, thus renewing the active surface with fresh mercury.
Turning now to FIG. 3, there is illustrated an exploded view of one example of a flowcell assembly (30), for analyzing a flowing stream of liquid (50), which includes a body (31), preferably made of a non-conductive plastic, a working electrode (35), described below, a reference electrode (32), comprising a AgCl coated silver disk on the end of a wire exiting the body, an auxiliary electrode (33), comprising a stainless steel tube which also serves to drain the flowing liquid from the body, and various bolts (37), connectors or spacers (38) and gaskets (39) for positioning the electrodes and holding the assembly together. Again, since the construction of, and ancillary electrical circuitry for using, reference electrodes and auxiliary electrodes are generally well known in the art, they will not be discussed in detail here.
The working electrode (35) comprises a chamber (41) in the body (31) for holding a small supply of fresh mercury, a threaded plug (49) for forcing mercury from the chamber as it is turned, and a metallic pin (34) for electrical connection to the mercury within the chamber. The mercury supply chamber (41) is in fluid communication with a short length of plastic tubing (42) which itself is connected to the input end of a tubular, semipermeable membrane (45) to form the active surface region (40), described below, of the working electrode. The output end of the tubular membrane (45) is connected to another short length of tubing (43) for conveying used mercury to a collection reservoir, which may be either a chamber (44) within the body (31) as illustrated in FIG. 3 or a container outside the cell, as was shown in FIG. 1.
Alternately, the working electrode (35) may comprise a somewhat simpler means for supplying a thread of mercury similar to that shown in FIG. 1, i.e. a remote syringe pump containing fresh mercury in communication with the membrane (45) via a longer length of plastic tubing (42) thereby eliminating the threaded plug (49) and internal mercury supply chamber. Such an arrangement has the advantage of easily being automated.
In use, a flowing stream of liquid (50) to be analyzed is introduced into the cell body (31) through inlet conduit (36) and flows to and through a central section of conduit (46) in which the tubular semipermeable membrane (45) which forms the working electrode's active surface region has been inserted, here transversely, into the liquid flow. A small diameter thread of liquid mercury is introduced into the tubular membrane (45) by rotating the threaded plug (49) into the body (31) to push mercury from the supply chamber (41) through the inlet tube (42). Mercury within the membrane, as well as the reference electrode (32) and the auxiliary electrode (33), is in electrical communication with the liquid (50) flowing in conduit (46) so that it may be analyzed. The metal tube (33), which serves as the auxiliary electrode, receives the liquid flow from the central section of the conduit and directs it out of the flowcell.
As better shown in FIG. 4, the active surface region (40) of the working electrode (35) is formed by the portion of the membrane (45) which extends through the conduit (46) carrying the flow (50) of liquid to be analyzed. Preferably, the tubes and conduits are held in place in the body by glue or cement (47). When a thread of mercury is advanced from the source through the membrane (45) and is properly charged, the type and amount of electroactive species in the liquid stream (50) which diffuse through the membrane's micropores can be analyzed. If the active surface becomes contaminated, it may be easily renewed by further advancing fresh mercury from the supply chamber (41) into and through the membrane. Or, in the alternate embodiment, fresh mercury may be supplied from a syringe pump to advance the thread through the membrane.
While the present invention has been described in terms more or less specific to one preferred embodiment, it is expected that various alterations, modifications, or permutations thereof will be readily apparent to those skilled in the art. Therefore, it should be understood that the invention is not to be limited to the specific features shown or described, but it is intended that all equivalents be embraced within the spirit and scope of the invention as defined by the appended claims.
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An improved mercury electrode for electrochemical analysis is formed by a small diameter thread of liquid mercury contained within an inert tube which, at one point along its length, has an short, fixed length of thin walled tubular semipermeable membrane surrounding and forming the electrodes' active surface in order to prevent or reduce fouling of the surface while allowing the mercury thread to be advanced through the membrane to expose a fresh active surface whenever desired.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The invention relates to a drill head and a method for percussive drilling implements in the field of horizontal drilling technology and claims the priority of German Patent Application 101 12 985.8, to which reference is made with regard to contents.
BACKGROUND
During horizontal drilling with a percussion implement, a hammer provided in the percussion implement is accelerated, for example with a source of pressure medium, such as water, air or other media. The kinetic energy of the hammer is directed without retardation into the drill head during the driving of the drilling implement. For the propulsion, the mass of the entire drilling implement located in the earth, including the pressure-medium hose, is to be accelerated. Furthermore, the skin friction of the drilling implement with the surrounding earth is to be overcome and displacement work is to be performed in the region of the drill head. All this is performed by the percussion piston.
Difficulties during the driving with such a percussion implement occur in particular in stony or rocky soils, in which the percussion energy partly applied by the skin friction and by the drilling implement mass to be moved is not sufficient in order to direct the shattering energy, required for overcoming an obstacle, into the obstacle, such as, for example, a stone or a piece of rock. This problem has been solved for quite some time by a special configuration of the driving heads (“stepped head”), as described in DE 25 58 842.5 A1.
The percussion energy can thus be directed into the obstacle as concentrically as possible by means of a stepped drill head in order to achieve the requisite shattering energy without the occurrence of substantial disadvantages with the displacement properties of the drill head.
DE 21 57 259 A1 and DE 26 34 066 A1 disclose a driving head which, movable in the axial direction, is connected to the percussion implement. As a result, uncoupling of the forward movement of driving head and percussion implement is achieved, which leads to the entire percussion energy of the percussion piston being available in a first step in the driving head for displacement work and for shattering obstacles. It is not until the obstacle at the face has been overcome, that is to say the path for the driving head is free, that the driving energy of the percussion piston is directed via the driving head no longer solely into the face, but rather a large proportion of said driving energy is directed via the connection between driving head and housing of the percussion implement into the percussion implement, so that the latter is drawn up.
Such a driving head has proved successful in practice and has been used for many years in horizontal percussion driving. However, depending on the dimensioning of the percussion implement or intractability of the obstacle to be overcome, there are practical limits, at given percussion energy, to the use of the driving head described.
BRIEF SUMMARY
The object of the invention, then, is to provide a percussion head which delivers an improved energy output for the driving, in particular in soils abounding in obstacles, and to provide a corresponding method.
The invention is based on the idea of using the percussion energy to be directed into the percussion head in an even more specific manner by energy being introduced in at least three steps.
The object of the invention is achieved by the subject matter of the independent claims. Advantageous designs are the subject matter of the subclaims.
The subject matter of the invention is not restricted to introduction of energy in three steps, since the number of steps can be as large as desired, but is described below with reference to said introduction of energy in three steps.
The introduction of energy in three steps enables the percussion energy to be used in a first step, for example, for overcoming a rocky obstacle essentially for shattering or otherwise for removing the obstacle. This can be realized by two or more elements which are axially movable relative to one another. In this case, “axially” does not mean that the elements have to lie on a geometrical axis. Thus, for example in a steering head, the axes of the impulse path may deviate from the geometrical axis, for example in the steering direction. The percussion energy may in this case be directed into the rock in a highly concentrated point-like manner via a percussion tip arranged in an axially movable manner without proportions of energy being lost for the propulsion of the percussion implement or of the rest of the percussion head. If the obstacle in the region of the percussion-head tip has been overcome, the percussion energy of the piston, in the second step, can be used for the “expansion” of the drill hole preformed in the first step. The preformed drill hole then already has a diameter equal to or greater than that of the machine housing. In the third step, the entire percussion energy can be used for the driving. In this step, the percussion energy, if substantial resistance is no longer to be overcome by the percussion-head tip and the rest of the percussion head, is then directed largely entirely into the body of the percussion implement for overcoming the skin friction and thus for the propulsion.
To this end, the percussion head may have two elements axially movable relative to one another. In this case, the percussion head, in detail, may have a displacement element which is connected to the body of the percussion implement in an axially displaceable manner and a chisel tip (percussion tip) which can be mounted centrally or eccentrically in the displacement element and is connected to the displacement element in an axially movable manner. In this case, the connection between percussion tip and displacement element, on the one hand, and displacement element and body of the percussion implement, on the other hand, has a front and a rear stop, which defines the axial stroke of the respective element of the percussion head.
The displacement element is preferably designed as a displacement ring having a central axial bore for the percussion tip. In particular for steered drilling, however, the displacement element may have a bore deviating from the axis of the drilling implement, either at an angle or parallel to the implement axis.
The percussion tip preferably extends integrally from the tip of the percussion head through the displacement element into the chamber of the percussion piston, in which case the term “integrally” is to be understood in terms of force not in terms of material. Thus the chisel may also be composed of two or more elements frictionally connected to one another.
Furthermore, the chisel or also the further percussion head elements may be held in the contracted basic position by a spring element, so that the axially displaceable percussion head elements return automatically into their basic position after the rapid advance caused by the percussion piston.
The invention is explained in more detail below with reference to an exemplary embodiment shown in the drawing.
BRIEF DESCRIPTION OF THE FIGURES
In the drawing:
FIGS. 1 to 3 show the percussion head according to the invention in three different functional positions,
FIG. 4 shows the percussion head according to the invention without restoring spring,
FIG. 5 shows another embodiment of the head according to the invention, and
FIG. 6 shows a further embodiment of the head according to the invention.
The first functional position shows the percussion head in the completely contracted state.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The percussion head 1 has a chisel 2 with a percussion tip 4 and an anvil 5 for the percussion piston 40 . The percussion tip has a stepped geometry and a cutting edge 6 .
The chisel 2 is arranged in a bore of the base 7 , which at the same time serves as an adapter for screwing into the body (not shown) of the percussion implement.
In its front region, the chisel 2 has a stepped attachment 8 which is axially fixed with respect to the chisel and a stepped attachment 10 which is axially displaceable with respect to the chisel. A preloaded spring 12 is provided in an annular space 11 of the percussion head base 7 in order to hold the chisel 2 in its basic position or to press it back into the latter.
An embodiment without a spring is shown in FIGS. 4 to 6 .
The attachment 8 is fixed on the chisel 2 with pins 14 , 16 . The attachment 10 is displaceable between a front stop 32 and a rear stop 34 relative to the attachment 8 and relative to the base 7 of the percussion head. The ratio between the step-like displacement sections 22 , 24 and 26 , 28 , 30 establishes in combination with the chisel head 4 the ratio of the force distribution between shattering and displacement work. In the extreme case, the attachment 8 can be omitted, so that the displacement work is performed essentially by the displacement attachment 10 . This may also be achieved by the displacement attachment 8 being fixed with respect to the displacement attachment 10 and being axially displaceable with respect to the chisel 2 . The attachments 8 , 10 , which are connected in a sliding-sleeve-like manner, have the sealing means 18 , 20 at their connecting points.
The functional positions shown in FIGS. 2 and 3 show the emergence of the chisel 2 from the percussion head 1 in a first section, in the course of which an annular space 36 is produced, and the emergence of the displacement attachment 10 from the percussion head 1 in a second section, in the course of which an annular space 38 is produced. After the impact, the spring 12 causes the chisel 2 to retract, which at the same time pushes the displacement attachment 10 back with it into its basic position. An embodiment without a spring is shown in FIG. 4 , in which embodiment the retraction is effected by the feed which acts on the base 7 and retracts the telescopically extended head.
The embodiments in FIGS. 5 and 6 have a special configuration in the region of the anvil 5 . In FIG. 5 , the percussion impulse is transmitted from the piston 40 via the chisel 2 to the base 7 . In FIG. 6 , the percussion impulse is first of all transmitted to the chisel 2 and then via the stop 45 to the base 7 , whereas the chisel 2 is limited in the forward direction via the cone 39 .
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The invention relates to a method for horizontal drilling with a percussion implement and a percussion head or percussion head element mounted in a movable manner relative to the percussion implement, the percussion impulse being transmitted in at least three steps.
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BACKGROUND
The present invention relates to a wood splitting device specifically designed for use with a skid steer loader. Wood splitting devices are well known and can be attached to a variety of devices. U.S. Pat. No. 4,240,476 discloses a log splitting attachment for use with a tractor. The use of hydraulics in connection with a log splitting device is also known. Most log splitting devices operate in the horizontal mode, however some can also operate in the vertical mode. U.S. Pat. No. 5,651,404 discloses a wood splitting assembly mounted on a trailer or truck bed. Two separate wood splitting assemblies are operated independently of each other and use a double stage hydraulic system. Vertical wood splitters are also known in the art as is set out in U.S. Pat. No. 4,945,960. Wood splitters are typically characterized by the position in which they are operated either horizontal and roughly parallel to the ground or vertical and roughly perpendicular to the ground. There are advantages and disadvantages of horizontal and vertical wood splitters and it would be desirable to have a wood splitter that could efficiently operate in both the vertical and horizontal mode.
In recent years skid steer loaders have become very popular due to their versatility and mobility. They have been popular because of the wide selection of useful attachments and number of tasks they can complete in a minimal amount of time. The popularity of skid steer loaders is so strong that the cost to own one has become very affordable.
It would further be desirable to have a log splitter attachment that would be able to connect with a skid steer loader and utilize the hydraulics from the skid steer loader in its operation.
Many times in chopping logs a wedge becomes stuck in the log and typically an operator has to physically remove the log from the wedge. It would be desirable to have a means of extracting the wedge from the log automatically without having to physically extract the wedge by hand.
SUMMARY INVENTION
The wood splitting attachment of the present invention is usually operated in the vertical and horizontal mode and connects readily to a skid steer loader. The wood splitting attachment includes wood supporting means which would preferably include an “I” beam, a head plate which is rigidly connected at one end of the “I” beam and a post for supporting the “I” beam when the “I” beam is positioned parallel to the ground in the horizontal mode of operation. A splitting wedge means associated with the wood supporting means is used for splitting the wood. Preferably the wood splitting means would be a splitting wedge. This splitting wedge is operated by a hydraulic means that would be suitable for attachment to a hydraulic power source. The hydraulic means would be operatively connected to the wood supporting means and the splitting wedge means for moving the splitting wedge means along the wood supporting means.
One of the real advantages of the present invention is the ability to easily operate the wood splitting attachment in both the horizontal and vertical mode and easily reposition the wood splitter from one mode to the other. To accomplish this, diverter means converted to the hydraulic means for diverting hydraulic fluid is utilized. The hydraulic means includes a hydraulic supply line, hydraulic return line and a hydraulic cylinder operably connected to the splitting wedge means and a control valve connected to the hydraulic supply line and the hydraulic cylinder. The hydraulic cylinder is connected to the hydraulic return line. The diverting means preferably includes a first and second diverter where the first diverter is connected to the hydraulic supply line at a point in the line prior to connection with the control valve and a second diverter connected to the hydraulic return line at a point after the return line exits the hydraulic cylinder.
The control means are operatively connected to both the splitting wedge means and the hydraulic means. The control means preferably includes a control valve for controlling operation of the wood splitting attachment in said horizontal mode. This allows for operation of the wood splitting attachment in the horizontal mode while standing next to the attachment and loading wood to be split. In the vertical mode where operation from the cab of the skid steer loader is critical the attachment can be operated from the cab. Ease of operation in both the vertical and horizontal mode is because of the utilization of the diverter, control and hydraulic means.
The wood splitting attachment is most efficiently used when connected to a skid steer loader and the hydraulic fluid power source is mounted on the skid steer loader. The wood splitting attachment, including the wood supporting means, splitting wedge means and hydraulic means, has connecting means preferably a mounting plate attached to the wood supporting means and hydraulic lines attached to the skid steer loader hydraulic system and the skid steer loader is connected to the log splitting attachment by means of the mounting plate. In order to give the wood splitter attachment some stability in operation, support legs are rigidly connected between the posts and the mounting plate.
The novel connection of a wood splitting attachment to skid steer loader results in a wood splitter with the advantages of being able to operate in a horizontal and vertical mode and the advantages of incorporating a skid steer loader.
Another aspect of the present invention is the wedge extracting means, which are connected to the wood supporting means on exterior of the splitting wedge. Wedge extractor means are preferably removably attached to the wood supporting means and would typically comprise two “L” shaped pieces of steel welded together in such a way that they mount on the exterior of the splitting wedge so the splitting wedge can pass along the wood supporting means between the wedge extractors. When the splitting wedge is withdrawn the wedge extractors contact the wood, allowing the splitting wedge to retract from the wood, thus extracting the splitting wedge from the wood.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is further described in connection with the accompanying drawings and which:
FIG. 1 is a perspective view of the current invention in the horizontal position.
FIG. 1A is a perspective view of the current invention in the vertical position.
FIG. 2 is a perspective view of the invention in the horizontal position.
FIG. 3A is a top plain view of the two stage splitting wedge.
FIG. 3B is a top view of the hydraulic cylinder and splitting wedge connection.
FIG. 3C is a side view of the two stage splitting wedge.
FIG. 4A is a side view of the wedge extractors.
FIG. 4B is a perspective view of the wedge extractors.
FIG. 4C is a front view of the wedge extractors.
FIG. 5 is a front view of the splitting wedge assembly and the wedge extractors.
FIG. 6 is a schematic diagram of the hydraulic hose and plumbing hardware.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a log splitter 11 , suitable for mounting on the front of a skid steer loader 13 , by means of quick connect mounting plate 15 common to skid steer loaders as shown in FIG. 1 .
The splitter as seen in FIG. 2, is constructed of a rigid “I” beam 10 , supported by a post 14 . At one end is a flat piece of steel 18 , with a common utility plate 20 , welded to it to form a mounting plate 19 for quick attachment to the skid steer loader. On the top edge of the utility plate 20 , are two foot plates 52 , with an anti-skid surface 52 A for entering the skid steer loader. At the other end of the “I” beam 10 , is a head plate, a thick piece of steel with a beveled edge 12 , for the log to rest against when being split in both the horizontal position as shown in FIG. 1, or vertical position as shown in FIG. 1 A. The beveled edge allows the head plate 12 to slide under the log when used in the vertical position shown in FIG. 1 A. Support legs 16 , prevent bending between the “I” beam 10 , and the mounting plate 19 .
On top of the “I” beam 10 , as shown in FIG. 2, a hydraulic cylinder 28 is mounted, between two pieces of steel 54 , with a pin 56 , slid through holding the hydraulic cylinder 28 in place at the one end. At the other end is the hydraulic cylinder rod eye 28 A, and pin assembly 37 as shown in FIG. 3 B. It is attached to the splitting head assembly as seen in FIGS. 3A & 3B. In FIGS. 3A-C, the hydraulic cylinder rod eye 28 A, is set between the pin collars 44 , and is attached by a pin 38 with a flat ear 39 , and held in place with a bolt 38 A. The pin collars 44 , are welded to a beveled piece of steel 36 , that are welded to the splitting base 30 , and the splitting wedge 34 . The splitting base 30 has a beveled edge on the lead edge 30 A (as shown in FIG. 2) and six holes drilled in it with bolts 42 , to allow a spacer 40 , the thickness of the beam, and a backing plate 32 , (as shown in FIGS. 2 & 5) that is as wide as the “I” beam flange to be attached. The distance between the spacers 40 is slightly larger than the “I” beam 10 , and so it will allow the entire wedge splitting assembly 58 , as seen in FIG. 5, to slide back and forth on the “I” beam 10 . Grease fitting 46 , allows for easy greasing and minimal wear between the wedge splitting assembly 58 , and “I” beam 10 , and smooth operation.
This wood splitting invention is unique in that it attaches to a skid steer loader and can be utilized in the vertical and horizontal positions without having to physically place the splitter in either position. In the vertical position the skid steer loader can be driven over to the larger logs and the log positioned on the splitter without having to physically lift or tilt the device by hand. When in the vertical position the logs would not have to be physically handled. When using the log splitter in the horizontal mode, it will not have to be detached from the skid steer loader, simply changing the hydraulic flow and repositioning the attachment for use in the horizontal mode provides for maximum versatility and log splitting production.
Splitting in the horizontal position is accomplished by first, positioning the skid steer loader 13 , as shown in FIG. 1, in line with utility plate 20 and attaching it to the skid steer loader 13 using the locking pins 48 , and then attaching both hydraulic lines 26 , to the skid loader auxiliary hydraulics 29 . The locking pins 48 and triple stage hydraulics, the ability to continuously flow, stop and start, and flow in reverse, all controlled by switches in the cab of the skid steer loader are common to skid steer loaders. To begin the process, the continuous flow hydraulic switch (not shown) on the skid steer loader is activated. The hydraulic fluid enters the coupler and supply line 26 A, as shown in FIG. 2, travels through the first diverter 22 A, and to the control valve 24 and stops. The operator, standing along-side the splitter places a log onto the “I” beam 10 , then pulls the control valve lever 25 , towards the head plate 12 . The hydraulic fluid then passes through the control valve 24 , through the first “T” fitting 50 A, to the back side of the hydraulic cylinder 28 , pushing the splitting wedge assembly 58 , down the “I” beam, 10 , contacting the log, splitting it. For operator safety, the wedge splitting assembly 58 , as shown in FIG. 5 stops several inches short of the head plate 12 , eliminating a pinch point. This is an important feature in that should the operator's hand, arm or other body parts be placed between the splitting wedge 34 and the head plate 12 an injury is much less likely to occur. The beveled pieces of steel 36 in each side of the wedge act as a log separator, aiding the splitting process by helping to separate the log while the splitting wedge 34 , travels down the “I” beam 10 . The fluid on the exhaust side of the hydraulic cylinder is pushed out and is blocked off by the second diverter 22 B, and is pushed back through the second “T” fitting 50 B, into the control valve 24 , through the other side of the second diverter 22 B, back to the skid steer loader. The control valve lever 25 is pulled towards the skid steer loader and the splitting wedge assembly 58 returns to its standing position ready for another log.
FIGS. 4A-C depict a three dimensional view of the wedge extractors 60 . The wedge extractors 60 consist of two pieces of “L” shaped angled steel, welded together, and bolted with bolts 64 and nuts 66 through bolt holes 62 as seen in FIG. 5 to each side of the “I” beam 10 . Both of the front edges of the wedge extractors 60 A (the edge closest to the head plate 12 ) are parallel with each other and the cutting edge of the splitting wedge 34 . They are also wrapped around the sliding wedge splitting assembly 58 as shown in FIG. 5 with sufficient clearance not to interfere with the movement of the splitting assembly. At times during either horizontal or vertical splitting the wedge 34 becomes stuck in the log. By returning the splitting wedge assembly 58 back to the starting position with the log still stuck onto the splitting wedge 34 , the wedge extractors 60 are positioned onto the “I” beam 10 to dislodge the log from the splitting wedge 34 separating the log and wedge 34 . This eliminates having to physically wrestle the log from the splitting wedge in the horizontal position or having to exit the skid steer loader to dislodge the log in the vertical position maximizing log splitting production.
FIG. 6 is a hydraulic hose schematic depicting the proper placement of hardware to make the current invention operate. In the horizontal position with the skid steer loaders continuous flow hydraulic fluid activated, hydraulic fluid enters through the supply coupler 26 A, then travels through the diverter 22 A, to the control valve 24 . When the operator activates the control valve lever 25 , fluid continues through the control valve 24 through the first “T” fitting 50 A to the back side of the hydraulic cylinder 28 causing the hydraulic cylinder 28 , to stroke out. Fluid on the exhaust side of the hydraulic cylinder 28 is pushed out and through the second “T” fitting 50 B, to the other diverter 22 B where it is stopped and passes back through control valve 24 , through diverter 22 B and diverted back to the skid steer loader through the return coupler 26 B. By stroking the control valve handle the other way the hydraulic cylinder will return.
In the vertical position both diverters 22 A and 22 B are engaged to allow the hydraulic fluid to flow from the skid steer loader, around the control valve to the hydraulic cylinder and return from the hydraulic cylinder around the control valve back to the skid steer loader. By starting, stopping and reversing the hydraulic fluid flow from the switch inside the cab of the skid steer loader you can control the direction of the hydraulic cylinder from inside the cab.
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A wood splitting attachment primarily for use with a skid steer loader that allows the wood splitter to be operated in the horizontal or vertical mode, can be easily connected to a skid steer loader and with a wedge extractor that allows the splitting wedge to be easily extracted from the wood is the subject of the present invention.
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RELATED TO U.S. APPLICATION DATA
[0001] This application claims the benefit of U.S. Provisional Application No. 60/180,332 filed on Feb. 4, 2000.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to dispensing systems and, in particular, to a dispensing system for freshening, deodorizing, sanitizing and disinfecting an area of interest such as, for example, urinals, commodes and the atmosphere in rest rooms.
[0003] It is known to provide dispensing systems for freshening, deodorizing, sanitizing and disinfecting the air and/or the water within, for example, rest rooms to overcome undesirable odors in the atmosphere and bacteria in urinals and commodes. Generally speaking, these dispensing systems are stand-alone, event-driven devices. For example, one type of atmospheric dispensing system includes a timer that controls the release into the atmosphere of an olfactory simulating material at periodic intervals. That is, either continually or during preset hours of operation, a timer triggers the release into the atmosphere of the olfactory simulating material at periodic intervals of, for example, about 15 minutes. One such atmospheric dispensing system including this type of a time-based event controller is described in commonly assigned, U.S. Pat. No. 5,772,074.
[0004] Another type of stand-alone, event-driven dispensing system for urinals and commodes releases a sanitary conditioning solution upon the activation of a flush valve. That is, as the flush valve of a urinal or commode is activated water passes through an inline sanitary conditioning system to the inlet of a bowl of the urinal or commode. The released water and the dispensing system cooperate to deliver water to the bowl that includes the sanitary conditioning solution. One example of this type of stand-alone, use-based event controlled sanitary device is described in commonly assigned, U.S. Pat. No. 6,009,567. The disclosure of U.S. Pat. Nos. 5,772,074 and 6,009,567 are incorporated by reference as if fully set forth herein.
[0005] The inventors of the present invention have realized that a perceived disadvantage in the event-driven control devices of conventional dispensing systems lies in their inability to monitor and respond to the load or demand placed on each device and the demand on the rest room or other room environments as a whole. It follows, therefore, that the conventional dispensing systems can not adequately respond to the situation in which the more persons utilizing a facility, the greater the bacteria deposited therein and the greater the potential odors arising therefrom.
[0006] Accordingly, the inventors have realized that there is a need for an interactive, demand-based dispensing system that coordinates the response of stand-alone dispensing devices within an area of interest to the number of persons utilizing the area to, in effect, substantially overcome the undesirable odors in the atmosphere and bacteria in urinals and commodes.
SUMMARY AND OBJECTIVES OF THE INVENTION
[0007] Therefore, it is a first object and advantage of the present invention to provide an interactive, demand-based dispensing system for sanitize conditioning an area of interest.
[0008] It is a further object and advantage of the present invention to provide a dispensing system that controls at least one stand-alone dispensing devices within an area of interest in response to the number of persons utilizing the area.
[0009] It is a still a further object and advantage of the present invention to provide a dispensing system that controls at least one stand-alone dispensing devices within an area of interest in response to sensing other criterions, such as vapor, odor, smell or fragrance by utilizing an electronic nose, such as that described below.
[0010] Further objects and advantages of this invention will become more apparent from a consideration of the drawings and ensuing description.
[0011] To overcome the perceived deficiencies in the prior art and to achieve the objects and advantages listed above, the present invention is, generally speaking, directed to a dispensing system for use in an area of interest, such as for example, and not limitation, a restroom. In a preferred embodiment, the system comprises at least one device for sanitize conditioning a medium. It should be understood that the term “sanitize conditioning” should be construed in its broadest sense as a system or device that may freshen, deodorize, sanitizes, disinfect or otherwise condition the medium. Likewise, the term “medium” should be understood to include air or water (as applicable). A sentry is also provided for detecting an object and for communicating with the at least one device. For this reason, the sentry comprises a detector for detecting the object and a controller, operatively coupled to the detector, for maintaining a count of the number of objects detected by the detector, wherein the controller transmits one or more variables, based on the count, to the at least one device to cause the at least one device to sanitize condition the medium in accordance with the one or more variables.
[0012] In preferred embodiments, if the medium is the air, the device may be mounted to or on a wall or the like. Similarly, if the medium is water, the device may be mounted on or in connection with a urinal or toilet. The area of interest may be a restroom and, if so, the sentry may be positioned proximate the entrance of the restroom. In this way, the detector may detect the presence of persons that enter and/or exit the restroom and may communicate the presence of such persons to the controller. In this manner, the controller may maintain a count of the number of people that enter and/or exit the area of interest, evaluate the count representing the number of people that have entered and/or exited the area of interest, and based on the count, communicate one or more variables to the device. Specifically, the one or more variables transmitted by the controller to the device may include the frequency and/or intensity of the sanitize conditioning of the medium by the device.
[0013] In a further preferred embodiment, the device may include a transmitter and the controller may include a receiver for receiving transmissions from the device. In this way, the device can communicate with the controller to indicate that the device requires, for example, a replenishment of a sanitize conditioning material. The sentry may even include a display for indicating a sanitary conditioning condition of the area of interest or the status of operability of the device.
[0014] It is within the scope of the invention to have a system in which there is a plurality of devices for sanitize conditioning both the air and the water in a restroom or other area of interest. The system may also include a plurality of sentries and a central unit for operable communication with each of the plurality of sentries, the central unit for at least one of monitoring and coordinating the response of each sentry of the plurality of sentries.
[0015] In a further embodiment, the sentry may be configured for detecting a vapor, odor, smell or fragrance and processing the detected vapor, odor, smell or fragrance. In this way, the controller may be configured to transmit one or more variables, based on the processed result of the detection, to the device to cause the device to sanitize condition the medium in accordance with the one or more variables. By way of example, the detector in this embodiment may be what is known in the art as an electronic nose.
[0016] In another embodiment, the controller may transmit information, based on the count, to the device to cause the device to sanitize condition the medium in accordance with one or more variables. In this way, the storage of the variables may take place in the device(s) and not the sentry itself.
[0017] Lastly, in accordance with the present invention, a method of sanitize conditioning at least one medium in an area of interest with a dispensing system comprising at least one device for sanitize conditioning the medium and a sentry for detecting an object and for communicating with the at least one device, is provided. This methodology preferably comprises the steps of detecting an object and maintaining a count of the number of objects detected and transmitting one or more variables, based on the count, to the device to cause the device to sanitize condition the medium in accordance with the one or more variables. In a particularly preferred embodiment, the method comprises the steps of detecting the presence of persons entering and/or exiting the area of interest and storing the number of such persons within a memory of the sentry, evaluating the count representing the number of people entering and/or exiting the area of interest, and based on the count, communicating the one or more variables to the at least one device. Here also, the one or more variables transmitted by the controller to the device may include the frequency and/or intensity of the sanitize conditioning of the medium by the device. Likewise, contemplated in the claimed methodology is the use of an electronic nose, use of a plurality of devices and/or sentries, and use of devices for sanitize conditioning both the air and water in an area of interest.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above set forth and other features of the invention are made more apparent in the ensuing Description of the Preferred Embodiments when read in conjunction with the attached Drawings, wherein:
[0019] [0019]FIG. 1 is a simplified perspective view of an area of interest having an interactive, demand-based dispensing system, constructed in accordance with the present invention;
[0020] [0020]FIG. 2 illustrates a flow diagram of operating functions for a controller of a demand-based dispensing system operating and constructed in accordance with a preferred embodiment of the present invention;
[0021] [0021]FIG. 3 is a simplified view of an exemplary look-up table that illustrates an exemplary configuration of user demand and corresponding operating variables for controlling stand-alone dispensing devices; and
[0022] [0022]FIG. 4 is a simplified block diagram, in partial cross-section, of the preferred embodiment of a sentry controller of the interactive, demand-based dispensing system of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] [0023]FIG. 1 illustrates a preferred embodiment of an interactive, demand-based dispensing system, generally indicated at 10 , constructed in accordance with the present invention. Dispensing system 10 sanitize conditions the air and/or water within an area of interest such as, for example, a rest room 12 . It should be understood that the term “sanitize conditioning” (or a form thereof) should be construed in its broadest sense as a system or device that may freshen, deodorize, sanitizes, disinfect or otherwise condition the air and/or water (as applicable) as would be understood in the art. The dispensing system 10 includes a sentry, generally indicated at 14 , and at least one standalone air and/or water sanitize conditioning device (e.g., devices 16 , 18 and 20 ). As can be seen in FIG. 1, the sanitize conditioning device may be mounted on a wall (device 16 ) for sanitize conditioning the air, or may be mounted on a toilet (device 18 ) for sanitize conditioning the water, or may be mounted on or in connection with a urinal (device 20 ) also for sanitize conditioning the water. Obviously, devices 18 and 20 may include features for sanitize conditioning the air as well.
[0024] Preferably, the sentry 14 is mounted within an entrance or doorway of the rest room 12 . For example, in FIG. 1, the sentry 14 is mounted on a door 22 of the rest room 12 . It should be appreciated that in other environments such as, for example, in a stadium or outdoor venue, the sentry 14 may be mounted on a wall or partition leading into an area wherein commodes or urinals are located.
[0025] Reference is now also made in conjunction with FIG. 2, to illustrate a simplified diagram of the operational logic of the sentry 14 . At Step 100 the sentry 14 monitors the activity of the rest room 12 by, for example, counting the number of persons that enter the rest room 12 . The sentry 14 includes a detector 24 and a controller 26 . The detector 24 comprises, for example, an infrared detector, video recorder, pressure sensitive switch, RF detector, sonar detector or photodetector, that senses the presence of an object (e.g. a person or portion thereof) on or within a desired distance, such as a range of about a few inches to a few feet, of the detector 24 . It should be appreciated that the desired distance of detection may vary from one installation to another and, therefore, it is within the scope of the present invention for the detector 24 to have a self compensating range detector and/or to permit an adjustment of the desired distance of detection.
[0026] As a person enters the rest room 12 , the detector 24 detects their presence and generates a signal to the controller 26 to count the person. The controller 26 , for example a microprocessor-based controller, includes an algorithm that performs the counting operation. As the program logic necessary to perform the counting operation is within the skill of those in the art, the details therein are not included herein. However, it should be appreciated that the algorithm should include a method of accommodating the fact that the detector 24 generally detects a person twice, i.e. entering and exiting the rest room 12 as well as those persons merely walking by and in close proximity to the sentry 14 .
[0027] A value representing a “count” of those persons utilizing the rest room 12 is determined at Step 110 and is equal to the activity or demand of the rest room 12 . In accordance with the present invention, the demand is periodically evaluated at Step 120 , for example at a predetermined polling period which varies from seconds to hours, after which a control signal is transmitted from the sentry 14 to at least one of the stand alone dispensing devices 16 , 18 and/or 20 . It should be appreciated that the polling period may be set according to the anticipated demand of the rest room 12 , i.e. more or less frequently than stated above. For example, if the dispensing system 10 is employed in a relatively high traffic environment such as an airport, railway or bus terminal, the polling period may be set to a more frequent time period, such as for example, varying every second to hours. In this way, the dispensing system's 10 response to the demand of the rest room 12 is optimized.
[0028] The evaluation process may include a look-up operation (Step 130 ) in which a table, such as a table 30 illustrated in FIG. 3, is referenced to provide variables and/or parameters to direct the operation of the dispensing devices 16 , 18 and/or 20 . For example, and with reference to FIG. 3, if the demand within the most recent polling period is eight (8) persons, then a “Demand” column of table 30 is searched to identify a value corresponding to the calculated demand of 8 persons. In this example, row 32 of table 30 is identified. Accordingly, the controller 26 extracts a “Cycle Frequency” variable of “10 minutes” and a “Intensity of Activation” variable of “Low.” Once the controller 26 retrieves the appropriate variables from the look-up table 30 , the controller 26 transmits these variables to the cooperating dispensing devices 16 , 18 and 20 at Step 140 . Preferably, the sentry 14 includes a transmitter 28 such as, for example a radio frequency (RF) or infrared (IR) transmitter, for transmitting signals 29 that include the operating variables to the dispensing devices 16 , 18 and 20 . The dispensing devices 16 , 18 and 20 include receivers (not shown) for receiving the transmitted signals 29 . The dispensing devices 16 , 18 and 20 are configured to be able to reset their operating variables to correspond to the most recently received values from the sentry 14 . Still further, it is within the contemplated configuration that the controller 26 transmits, to one or more of the device, information based on which the device accesses its respective own look up table in its own memory, and sanitize conditions the air and/or water based thereon. That is, the aforementioned look-up table need not be located in the controller but rather in the respective device(s). In this way, controller 26 need now only transmit to the appropriate device(s) the “Demand”. With such “Demand” information, the device can adjust its variables for appropriate actuation. As such, the sentry 14 controls, in a demand-based manner, the dispensing devices 16 , 18 and 20 and, in effect, the complete sanitize conditioning, such as by freshening, deodorizing, sanitizing, disinfecting and/or otherwise conditioning the air and/or water (as the case may be) within the rest room 12 .
[0029] Although not included in the flow diagram of FIG. 2, it should be appreciated that the controller 26 may include a default process wherein each of the stand-alone dispensing devices 16 , 18 and 20 are cycled (i.e. automatically activated) at a predetermined time of day or after a predetermined number of hours of non-use (i.e. after 12 hours of non-use).
[0030] In one embodiment, the sentry 14 and each of the dispensing devices 16 , 18 and 20 may include transceivers such that signals may be transmitted and received between the sentry 14 and the respective devices 16 , 18 and/or 20 . Such a communication protocol would be well understood in the art and therefore, details thereof shall be omitted for brevity. However, the two-way lines of communication in FIG. 1 are deemed to represent communication via a two-way system with one or more of the devices 16 , 18 or 20 and the sentry 14 including transceivers. In this way, the stand-alone dispensing devices 16 , 18 and 20 may notify the sentry 14 of their status, e.g., that one of the stand-alone devices 16 , 18 and 20 requires service as the sanitize conditioning material within the device has been completely dispensed.
[0031] [0031]FIG. 4 illustrates one embodiment of the sentry 14 . As shown in FIG. 4, the sentry 14 may include the detector 24 , the controller 26 , the transmitter 28 and a display 34 . The display 34 , which may be, for example, a liquid crystal display, receives signals from the controller 26 to exhibit numbers, letters and/or symbols of interest. For example, the display 34 may exhibit informational or advertising messages to persons using the rest room or passing in proximity thereto. The informational messages may include a notice of the sanitary condition of the rest room 12 or of any one or more of the dispensing devices communicating to the sentry 14 .
[0032] Preferably, the controller 26 may maintain statistics such as, for example, the number of persons counted using or passing by the rest room. The count may be retrieved to provide potential advertisers an indication of the “traffic” (i.e. persons per hour, per day or any other period of interest) passing by the display 34 . For example, it may be of interest to identify traffic patterns within the maintained statistics such that a time period in which a maximum number of persons passing by the sentry 14 may be identified. It follows that it may be more desirable to advertise during the determined time period of maximum traffic.
[0033] In another aspect of the present invention, the maintained statistics of usage are stored as, for example, a history of demand within the environment of interest. Such a history may be utilized by the controller 26 and/or persons monitoring the dispensing system 10 to anticipate future demand on the stand-alone devices, e.g. devices 16 , 18 and 20 . For example, maintenance personnel monitoring the system 10 can ensure an adequate supply of sanitize conditioning material (such as that which may freshen, deodorize, sanitize, disinfect and/or otherwise condition the water and/or air) is present within each device 16 , 18 and/or 20 to meet the anticipated needs of the system 10 over a predetermined period of time, for example, the next 12 or 24 hours, or longer.
[0034] In yet another aspect of the present invention, a number of systems, such as system 10 , may be located throughout, for example, a building or other structure. It is within the scope of the present invention for each of the system 10 to communicate with a central location that monitors and/or coordinates the response of each system 10 . As such, the demand on each system 10 may be monitored as well as the status of one or more stand-alone device within the building so that, for example, maintenance personnel may be dispatched from the central location if a undesirable status is received from one of the systems 10 or a stand-alone device located therein.
[0035] It should be appreciated that when multiple systems such as system 10 are located within a structure and, in particular, when more than one systems 10 are located in proximity to each other, there may be interference between the transmitted signals, i.e. signals 29 , of each system 10 . Therefore, it is also within the scope of the present invention for the transmitter 28 of each system 10 to transmit signals 29 within a predetermined range of frequencies. Similarly, each receiver of each of the devices 16 , 18 and/or 20 is capable of receiving the transmitted signals within the predetermined range of frequencies. Accordingly, transmitted signals within systems 10 located in proximity can be adjusted such that interference between the systems 10 is substantially eliminated.
[0036] It is also envisioned and contemplated by the present invention that a plurality of devices may communicate with each other. For this reason, it is also contemplated that each device may be configured for communication with each other in the event, for example, that a particular device is out of range of the sentry 14 , but yet that particular device needs to communicate with the sentry 14 . For example, in a large area of interest it is envisioned that the sentry 14 may not be able to transmit a signal strong enough to communicate with a particular device because the device is located too far away from the sentry or in a position not easily communicatable with the sentry. This can be based on a plurality of reasons, some of which are battery power constraints and/or physical impediments, such as walls, partitions etc. In these situations, it is easier to have a relay configuration, wherein the devices relay information between one another until the desired device is reached. Such a network configuration is well known in the art and can improve battery life in the sentry and/or devices, thus illustrating one advantage thereof.
[0037] Although described in the context of preferred embodiments, it should be realized that a number of modifications to these teachings may occur to one skilled in the art.
[0038] For example, in addition to or in place of detector 28 as disclosed above, sentry 14 may include what is known in the art as an “Electronic Nose,” which generally speaking, includes an array of sensors for recognizing and quantifying the concentrations of specific vapor mixtures (i.e. fragrances) containing many different chemical species. For example, instead of or in addition to the detector disclosed above, the Electronic Nose may provide an additional criterion for which communication to the devices to sanitize condition the air is necessary. That is, such an Electronic Nose may assist in providing additional information to the controller 26 , based on the scent or odor (for example) in the area of interest, to cause the controller 26 to communicate properly to the devices 16 , 18 and/or 20 . Accordingly, for purposes of an enabling embodiment, it should be understood that detector 28 should be understood to be, in a preferred embodiment, an Electronic Nose and the controller should be configured accordingly to process such information. Although such a construction would be understood in the art, reference is made to the publication “Electronic Nose Simulation of Olfactory Response Containing 500 Orthogonal Sensors in 10 Seconds,” by Edward J. Staples, the disclosure of which is incorporated by reference as if fully set forth herein.
[0039] Also, by example, and as discussed above, the teachings of this invention are not intended to be limited to the control of any specific type or number of stand-alone dispensing device. That is, control of any number of air and/or water purifying devices is contemplated.
[0040] While the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope and spirit of the invention.
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A dispensing system for use in an area of interest, the system comprising at least one device for sanitize conditioning a medium, a sentry for detecting an object and for communicating with the at least one device, the sentry itself comprising a detector for detecting the object and a controller, operatively coupled to the detector, for maintaining a count of the number of objects detected by the detector, wherein the controller transmits one or more variables, based on the count, to the at least one device to cause the at least one device to sanitize condition the medium in accordance with the one or more variables.
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The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalties thereon.
BACKGROUND OF THE INVENTION
Grossberg teaches (Studies of Mind and Brain, Stephen Grossberg, Reidel Publishing Co., Boston, 1982) adaptive neural networks which can be trained to recognize an input distribution and also to recall previously memorized distributions. The former networks are called instars and the latter are called outstars. He further teaches self-regulating subnetworks which provide short-term memory, reset, and activity normalization, and are called shunting, recurrent, inhibitory on-center/off-surround networks.
Symbolic substitution consists of first identifying a given symbol or pattern, and then substituting in its place another symbol or pattern. If the patterns are devised to correspond to binary numbers, and if the replacement rule is devised to correspond to arithmetic rules, then symbolic substitution can be used to design digital computing architectures. This is how the basic relationship can be reduced to practice: Use an instar to recognize a pattern and an outstar to write another pattern and use neural network techniques to perform the substitution act.
SUMMARY OF THE INVENTION
This disclosure describes a new circuit which performs the arithmetic sum of two N-bit binary numbers using parallel neural networks. Previous art requires sequential and serial operations to account for the carry bits which may be generated at each successive partial sum. The method described here is parallel and accounts for all carry operations. It results from the discovery of a fundamental relationship between symbolic substitution and neural networks.
The device embodied by the described circuit is a practical implementation of this basic relationship.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the register symbology.
FIGS. 2a and 2b illustrate hardware for Rules A and B.
FIGS. 3 and 4 show certain elements in great detail.
FIG. 5 illustrates an N-bit full binary adder network.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The binary addition rules are: ##EQU1##
The carry function in adding two numbers causes a lot of lost operation time, as the above addition rules do not directly provide for it.
Consider two N-bit binary numbers in two registers with an overflow bin on the left. Initially the overflow bin is at zero. The first new rule of the present invention is (Rule 1) that if all the top N bits are zero, then the lower register plus the overflow bin contains a number equal to the desired answer.
The new two positional rules are (Rules 2A and 2B)
______________________________________(A) the pattern 1 is replaced by 0 , and 0 1(B) the pattern 0 1 is replaced by 1 0 1 0______________________________________
The last rule (Rule 3) is that no changes are made for any other pattern. These rules, when repeatedly applied, eventually produce a state with all zeros in the top register ). Note that we can always begin with zero in the overflow bin (which is considered with the top register for pattern replacement and with the bottom register for the read out of the answer). Thus, at worst, (with all 1's) we can always apply rule 2B there. This generates zeros in the MSB (most significant bit), which allows for rule 2B to be applied again. Thus, rule 2B creates zeros, and rule 2A puts zeros on top. In order for these rules to not interfere, we can require that the replacement action take place much faster than the recognition action. ##STR1##
The above operations are all done in parallel. ##STR2##
So we now have the arithmetic rules in terms of symbolic substitution rules. Now go to neural instars and outstars to design networks for the rules 2A and 2B. First change everything into elementary neural nodes. Each bin is now a single node with output states 0 and 1 in accordance to the numbers to be added and has a recurrent loop which maintains its value in STM (short term memory). It can receive inputs, and has weights which are positive, zero, or negative/inhibitory. Thus a node can be at zero, then receive +1 and be changed to a +1. Later the node can receive a -1(after weighting) which will reset it to zero. The recurrent loop of a node keeps it in its current state even after the other inputs go to zero.
Recognition: Instar weights are proportional to the pattern to be recognized. For the substitution (outstars), we can take advantage of the fact that we already know the old pattern and can simply inhibit the active sites and excite the inactive sites as required. Thus for rule 2A and 2B we have the neural networks shown in FIGS. 2A and 2B respectively. Finally we can merge them into the overall network for the N-bit adder to get the design of FIG. 5.
FIG. 2A shows the hardware for wiring up the registers A and B for operation of rule 2A. The outputs of bins 21 and 22 which are the same significance bit of registers A and B are fed to a processor 20. Processor 20 will have an output if the sum of its inputs 23 and 24 times the weight or operator (+1 or -1) is equal to more than 0. In this case this will only happen if the bin 21 has a positive output put +1 and bin 22 has a zero output. With an output from processor 20 the bin 21 will now have an additional negative input (after weighting) which will cause bin 21 to go to a zero output and bin 22 will have an additional positive input which will cause bin 22 to go to a positive output. From this it can be seen that if bin 21 was originally a +1 and bin 22 a 0 , then the processor would cause the shifting of the +1 in bin 21 down to bin 22 as required by rule 2A.
FIG. 2B illustrates rule 2B. The processor 25 will have an output only when the sum of its inputs times the weight factors total a sum greater than 0. Due to the fixed bias input, it can easily be seen that if the next significant bin 28 has a positive output then processor 25 will not have an output even if bins 26 and 27 are positive; therefore, the next significant bit bin 28 has to be a zero. Further it can be seen that if either of the bit bins 26 or 27 of register A and B are zero regardless of bin 28, then the processor will not have an output. So only when both bins 26 and 27 have +1 outputs and bin 28 has a zero output will processor 25 have an output. Processor's 25 output changes the bins 26 and 27 to zeros and changes bin 28 to a plus one in accordance with rule 2B. Any other combination of the bins 26, 27, and 28 will result in no output of the processor and therefore no change of the bins of this circuit.
FIG. 3 illustrates in greater detail the circuitry of the bins of the registers. A summing device 31 has all the inputs connected to it and it will have an output which is the sum of the total number of inputs times their sign factors. This output could possibly be more than a +1, such as +2; therefore, a threshold device 32 is provided. The threshold device 32 will have a +1 output anytime its input is greater than zero. When the input threshold device 32 is zero or less it will have a zero output. A feedback circuit 33 is provided for maintaining the bin 31 in a positive condition even after the inputs initially causing it to be positive are reduced to zero. This will allow the bin 31 to retain a number once it has been programmed into the bin by either the present circuit or the circuits not shown which set the numbers into the registers A and B.
FIG. 4 shows the processor illustrated in greater detail and shows that a summing device 41 is connected to all of the inputs. The output of the summing device will be the sum of all its inputs. A threshold device 42 is provided so as to limit the total output of the circuit to a single 0 or +1 output. The output of the threshold device 42 like the threshold device 32 is a +1 when the input is greater than zero and is a zero when the input is zero or less.
FIG. 5 shows a N-bit full binary adder network in accordance to the present invention. Binary numbers are fed into registers A and B by common circuitry not shown. Appropriate timing circuits (not shown) will cause the processing of the rules 2A and 2B in parallel in accordance with the processors 53 and 54. A readout device 55 is connected to the outputs of register B plus the overflow so as to give a readout of the final state of the values contained in register B.
As is indicated by FIG. 5, the overflow bin is for purposes of comparison indicating as being in register A; however, for the readout it is connected directly to the readout device 55. The timing circuits will cause the operations to continue until zero across the board is found in register A (not counting the overflow bin). At this time the sum of the original values in the two registers will now be register B plus overflow. This can be read out by readout device 55. As can be seen from the circuit, in each timing cycle all the operations take place in parallel. The recognition should be keyed to be slower than the changing of the registers A and B. The mean time to perform the addition depends on the particular binary pattern made by the two particular numbers. It can be as fast as one substitution cycle or as long as approximately N such cycles.
A third register is not necessary in order to add two binary numbers in that register B performs the dual function of containing an original number and acting as a buffer register to contain the sum of the numbers. From analysis of the circuitry it is noted that processors 53 and 54 can never have adjacent units having a one-output simultaneously. Therefore, there can be no potential interference between the output of the processors.
The inputs to the processors could be considered as weighted inputs, and each input indicated with a negative weighting could be implemented by inserting an invertor in series with the line.
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A method for performing the addition of two N-bit binary numbers using palel neural networks. The value of a first register is converted and transferred into a second register in a mathematical fashion so as to add the numbers of the first register into the second register. When the first register contains all zeros then the desired sum is found in the second register.
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BACKGROUND OF THE INVENTION
The invention pertains to the field of gasoline saving devices for internal combustion engines wherein a signal is produced if the engine accelerator pedal is depressed at an excessive rate.
It has long been recognized that the operating characteristics of an internal combustion engine, particularly an automobile engine, can be improved if the rate of acceleration of the engine is commensurate with the ability of the engine to accelerate. However, with a manually operated accelerator pedal, usually a foot pedal, there is a tendency for many drivers to depress the accelerator, and open the throttle valve, at a rate greater than the rate which the engine actually accelerates and is capable of using fuel. This discrepancy between the rate of accelerator throttle operation, and the ability of the engine to accommodate the call for acceleration, causes an excessively rich fuel mixture to be introduced into the engine, wasting gasoline, producing unburned gasoline with the engine cylinders, and often causing a dilution of the motor oil. Such a rich fuel mixture also produces highly undesirable and contaminating engine pollution and in view of the present shortage of gasoline, and emphasis on clean air, the over rich fuel mixture is most objectionable.
A number of complicated throttle control devices are known wherein "over-acceleration" is prevented by controlling the rate of movement of the accelerator pedal and linkages, or relating the acceleration to the intake manifold pressure, as, in one such device as disclosed in the applicant's expired U.S. Pat. No. 2,157,652.
While known throttle control devices, and intake manifold pressure regulated apparatus, are effective to minimize the wasting of gasoline, such devices are expensive, and often objectionable from the driver's point of view in that they adversely affect the "feel" highly desirable to the operator with respect to the operation of the vehicle and tend to "override" the driver's control.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an inexpensive, simple, readily installable device which indicates an excessive rate of internal combustion engine accelerator pedal movement whereby the wasting of gas and inefficient driving habits attendant therewith due to accelerator pedal movement is immediately indicated to the operator in an audible manner.
A further object of the invention is to provide a gasoline saving device for use with a motor vehicle which is dependable in operation, may be readily used and understood by the unskilled, and produces an audible signal when an excessive rate of accelerator pedal operation occurs.
An additional object of the invention is to provide an economical internal combustion engine accelerator movement indicator which is capable of being adjusted to accommodate various engines and accelerator movements to produce the most effective sensing characteristics for a particular vehicle.
In the practice of the invention an expansible chamber motor in the form of a bellows having closed ends is attached to the underside of the vehicle accelerator foot pedal. As the foot pedal is depressed the expansible chamber is compressed forcing the air therefrom. At least a portion of the expelled air passes through a reed device, and if the velocity of the air passing through the reed device is sufficient, an audible signal is produced to indicate to the driver that the rate of accelerator depression is excessive.
Vents are preferably provided whereby air may escape from the bellows during accelerator depression, as well as pass through the reed device. An adjustable valve member is used to selectively close the vents as desired, thereby permitting regulation of the amount of air passing through the reed device for a particular engine and accelerator combination. By positioning the valve the device may be "customized" with respect to each vehicle and operator.
An elastomer band is used to affix the device to the underside of an accelerator pedal, and the means of attachment is universal as to readily permit the device to be attached to practically all accelerators without requiring special skills. The device does not interfere with the normal operation of the accelerator pedal, and permits the intended extent of movement without hampering or affecting the "feel" of the accelerator pedal movement. The accelerator may be quickly fully depressed in order to provide maximum acceleration for safety purposes, and the signaling of the apparatus can be ignored, if desired, as the audible signal produced serves only as a reminder, and does not impose an undesired or uncontrolled operation upon the vehicle operation or its throttle linkage.
BRIEF DESCRIPTION OF THE DRAWINGS
The aforementioned objects of the invention, and the operation thereof, are described in the following specification, and the invention is illustrated in the following drawings wherein:
FIG. 1 is a perspective view of an accelerator movement indicator constructed in accord with the invention as mounted upon an accelerator pedal,
FIG. 2 is a top, elevational view of the indicator with the valve disk in a half open position,
FIG. 3 is a bottom view of the indicator,
FIG. 4 is an elevational, sectional view as taken through section IV--IV of FIG. 2, and
FIG. 5 is an enlarged, detail, elevational view along section V--V of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The accelerator movement indicator in accord with the invention basically comprises an expansible chamber motor in the form of a bellows 10. The bellows includes an annular, flexible, sinuous wall 12 formed of an elastomer, such as rubber, neoprene, vinyl, etc. Preferably, the elastomer material of the wall 12 is of such a character as to have a biasing action when the wall is longitudinally compressed tending to restore the wall to its original axial length after the compressive forces have been released.
The ends of the bellows are closed by a pair of rigid head plates, which may be formed of metal as illustrated, or could be of a synthetic plastic material. The head 14 constitutes the upper head, while the head 16 forms the bottom or lower head. The heads are each of an annular configuration, and are of such a diameter as to permit the last corrugation at each end of the wall 12 to fit about the periphery of the associated head to form a sealed relationship therewith.
The upper head 14 is provided with a plurality of air vent holes 18, FIG. 2, four being illustrated in the disclosed embodiment. A valve disk or plate 20, preferably formed of a synthetic plastic material which is transparent or translucent, directly engages the outer surface of the head 14, and the valve disk is provided with a valve opening 22, and a similar finger receiving opening 24 in diametrical relationsip to opening 22. The diameter of the valve opening 22 is sufficient to selectively permit all four vents 18 to be in alignment therewith permitting maximum venting of the bellows to the atmosphere. By rotating the valve disk, 20 upon the head 14, by placing one's fingers in the openings 22 and 24, one, two, three, four or no air vents may selectively communicate with the atmosphere, and in this manner the degree of venting of the bellows may be regulated. In FIG. 2 the venting through two air vents is illustrated in solid lines and the dotted lines show the venting of four vents.
Prior to assemblying the upper head plate 14 and the valve disk 20 to the upper end of the bellows wall 12 an annular elastomer band 26 is stretched over the head and disk in a diametrical manner, as will be appreciated from FIGS. 2, 4 and 5. The three assembled components are then located within the uppermost corrugation of the bellows, and the bellows is slightly stretched to snugly embrace the head, while the bellow's wall portion 28 will overlap the head, and engage the disk and maintain the disk in firm relationship to the head, yet permit the disk to be selectively rotated with respect to the head. As will be appreciated from the drawings, the upper segment of the band 26 is exteriorly accessible.
The lower head 16 is assembled to the lower portion of the wall 12 in a manner similar to that employed with head 14, i.e., the wall is slightly stretched to receive the periphery of the head within the lowermost corrugation.
An audible sound producing device, constituting a reed whistle or "tweeter" 30 is located within the bellow's wall communicating with the bellow's chamber and the atmosphere. The reed device 30 includes a vibratable reed 32, and is one of the well known type wherein the passage of a sufficient amount of air at a given velocity from the bellows to the atmosphere causes the reed to vibrate and produce an audible signal.
The accelerator movement indicator is assembled to a conventional automobile accelerator pedal 34 in a manner shown in FIG. 1. The accelerator pedal 34 is connected to the usual throttle linkage 36, and may be pivotally mounted to the passenger compartment floor board at the lower end of the pedal, or the pedal may be pivotally connected to the fire wall by the linkage 36. With either type of accelerator construction the locating of the indicator on the underside of the pedal may be easily accomplished by pulling the accessible elastomer band portion away from the head 14 and slipping the bellows under the accelerator pedal so that the band portion passes across the upper surface of the pedal. If the throttle linkage 36 has been temporarily disconnected from the pedal 34 it should then be reconnected.
The operator utilizes the accelerator foot pedal in the normal fashion, depressing the pedal to produce engine acceleration. Depressing the accelerator pedal 34 causes the bellows 10 to be compressed and the air within the bellows is exhausted to atmosphere through the reed device 30, and the air vents 18 not covered by the valve disk 20.
If the operator depresses the accelerator pedal at an excessive rate which would waste gasoline the flow of air through the reed device 30 will be of such velocity as to cause the reed to vibrate producing an audible signal. This signal will remind the operator that the accelerator pedal is being depressed too rapidly and remind the operator to use a more gentle and uniform pressure in order to prevent an excessive rate of accelerator depression. As the accelerator pedal is released or "backed off" the biasing forces inherent within the material of wall 12 will restore the bellows to the maximum volume capacity. If desired a compression spring could be located with the bellows between heads 14 and 16 to augment the restoration of the bellow's shape.
By adjusting the valve disk 20 with respect to the air vents 18 the amount of air flowing through the reed device 30 during the bellow's compression can be regulated. The more air vents uncovered by the opening 22, the less the amount of air flowing through the reed device and the greater the rate of compression of the bellows permitted before the audible signal is produced. Conversely, by rotating the valve disk 20 to cover all of the air vents, air escapes from the bellows only through the reed device producing a very sensitive operation. Thus, it will be appreciated by varying the position of the valve disk, the degree of sensitivity of the accelerator movement indicator may be accurately varied, to produce that operation most desirable for a particular size and type of automobile engine, and also in accordance with the driver's preference.
Use of the indicator in accord with the invention soon develops good driving habits producing the most efficient use of gasoline and highest engine performance, and the simplicity of operation, economics of manufacture and ease of installation make the indicator in accord with the invention practical in every respect.
It is appreciated that various modifications to the disclosed embodiment may be apparent to those skilled in the art without departing from the scope of the invention.
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A device for attaching to the underside of an internal combustion engine accelerator which is compressed during depressing of the accelerator. A rate of accelerator depression faster than that efficiently necessary causes the device to emit an audible signal indicating excessively rapid accelerator movement such as causes the wasting of gasoline. The device comprises an expansible chamber motor in the form of a bellows having a reed type sound producing element actuated by air forced from the bellows during accelerator depression.
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STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
BACKGROUND OF THE INVENTION
The present invention relates generally to slab laser materials and more specifically to a laser design that uses two similar materials, one laser active and one not active, that are bonded together to form a composite slab of material. Appropriate antireflection coatings (to pump through) or TIR preserving and bonding coatings (to heatsink to) are placed on the TIR surfaces of the slab.
Slab laser materials and disk lasers share some aspects of the invention. These laser geometries have been described by multiple groups, and examples are described in the following U.S. Patents, the disclosures of which are incorporated herein by reference:
U.S. Pat. No. 4,725,787
U.S. Pat. No. 6,134,258
U.S. Pat. No. 6,094,297
U.S. Pat. No. 5,651,021
The best reference is the Phase-conjugated hybrid slab laser of U.S. Pat. No. 4,725,787. It shows a relatively low-power but high-quality laser oscillator couple to a high-power laser amplifier. The amplifier includes a rectangular slab of laser active material, and a phase-conjugate end mirror.
SUMMARY OF THE INVENTION
The present invention is a laser design that provides a method to efficiently pump laser materials so that pump energy is confined to the amplifying mode volume. Especially useful in quasi-three level materials because the design reduces the effect of reabsorption in weakly pumped regions of the gain media. Provides a higher damage threshold than that achieved in thin disk laser media.
As mentioned above, slab laser materials and disk lasers share some aspects of the invention. These laser geometries have been described by multiple groups.
One embodiment uses a slab of active laser material, for instance Yb:YAG, capped by a nonactive material, for instance undoped YAG or sapphire. The two materials are bonded together, for instance by diffusion bonding. The composite slab is then cut and polished to serve as a laser gain module. The slab can be Brewster-cut or flat-flat and antireflection coated on the ends. Alternatively, the nonactive material can be sandwiched between two active regions.
The slab is pumped from the top face like a disk laser or from the end like a longitudinally pumped slab. The slab could also be side-pumped using close coupled diodes. The preferred pumping mechanism depends on the pump source used. The slab generates or amplifies a laser beam that is longitudinally coupled into the device through the end (possibly Brewster-cut) surfaces. The laser beam bounces via total internal reflection within the slab passing one or more times through the active part(s) of the medium. The active region can vary in thickness. The thickness is chosen to minimize thermal and/or stress gradients in the material.
One of both of the large flat TIR surfaces of the slab is placed against a heatsink. A multilayer coating consisting of (1) a TIR preserving coating and a metallic coating is placed on each of the TIR-surfaces. In some embodiments a highly reflecting dielectric coating is also placed between the TIR preserving and metallic coating. The other TIR surface can be antireflection coated, for instance to pump through, or have the TIR preserving and metallic coatings to serve as a cooling surface.
All embodiment of the invention use two similar materials, one laser active and one not active, that are bonded together to form a composite slab of material. Appropriate antireflection coatings (to pump through) or TIR preserving and bonding coatings (to heatsink to) are placed on the TIR surfaces of the slab.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of the hybrid slab laser layers considered in the FEM thermal analysis with an end pump laser.
FIG. 2 is a graph that plots maximum temperature and stresses in the Yb:YAG layer of a hybrid slab gain medium as a function of Yb:YAG layer thickness. The set of cases assumes a 1.05 mm diameter pump beam and 5.3 W of heat deposited in each pump spot. The boundary conditions assume that the copper heatsink is held at −20° C. and the top of the slab is exposed to dry nitrogen at +25° C.
FIG. 3 is a view of the top pumped hybrid slab laser of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is a design for lasers and amplifiers based on hybrid slab active mirrors. In this design two similar materials, one laser active and one not active, that are bonded together to form a composite slab of material. Appropriate antireflection coatings (to pump through) or TIR preserving and bonding coatings (to heatsink to) are placed on the RIT surfaces of the slab.
The reader's attention is now directed towards FIG. 1, which is an end pumped hybrid slab laser that has a pump beam source 100 stimulating the active area of a laser 105 bounded by a mirror 110 to produce an output laser beam. While the mirror 110 induces some losses, the internal light can be amplified by the Yb:YAG 130 so it is reflected without losses. The inactive laser is embodied in layers 120 - 150 , which do not induce losing but are used to amplify internally reflected signals.
FIGS. 1 and 3 show a hybrid slab laser system for use with a pump laser that emits a laser pumping beam that provides pump energy to the hybrid slab laser. In FIG. 1, the hybrid slab laser system includes:
an active laser substrate 105 which has a top side and a bottom side and which contains material layers which are stimulated the laser pumping beam to emit a laser output beam;
a mirror 110 fixed to the bottom side of the active layer substrate;
an undoped YAG layer 120 that is face bonded to the top side of the active layer substrate and through which laser signals from the active layer substrate passes;
a Yb doped YAG layer 130 that is fixed above the undoped YAG layer and which amplifies laser signals from the active layer back into the amplifying mode volume of the active layer substrate with no losses;
an metallic reflecting coating 150 which is fixed above the Yb doped YAG layer to reflect laser signals back through the Yb doped YAG layer into the active layer substrate; and
a heat sink 190 which is fixed above the metallic reflecting coating to reduce thermal effects of the laser signals. Also shown in FIG. 1 is the HR. Dielectric coating 145 , and a TIR preserving coating 140 , but these are not essential to practice the inventions.
If the slab is end-pumped it resembles a rod laser. The slab can be illuminated from the top or bottom to perform as a disk laser as described below.
FIG. 1 shows a schematic of the hybrid slab gain medium. A Finite Element Model (FEM) was developed for this laser using the commercial code COSMOS/M. Because we wished to optimize our overall laser efficiency we assumed that only the “TIR points” in the Yb:YAG region were pumped rather than the entire slab or active region of the slab. Consequently, each pumped TIR point acts like a disk laser with an undoped YAG cap. Because of the device symmetry the FEM was developed for a quarter cylinder volume containing one TIR point (i.e. the model considered a quarter cylinder that was cut through the slab from air to the heat sink).
Several models were generated as we optimized the system. A typical model would contain 2,185 nodes and 1,848 elements. The model is severely reduced (i.e. deliberately small) to enable it to run fast and permit parametric studies of the relationships between the TIR spot (diameter, thickness and energy density) and the maximum system temperatures and stresses. In general, the more finely the FEM is meshed, the more accurate the results. However, the model run time increases a square of the number of nodes and the number of nodes increases as the cube of the number of elements on a side. Therefore, in practice one must trade run time versus the ability to make parametric studies. Several different size models were operated to ensure that reducing the number of nodes did not decrease model accuracy too much. In practice, we were able to keep the model small by taking advantage of the various planes of symmetry available and the fact that the effects of the thermal loading are relatively localized. The model was built up using individual material properties for the discrete layers shown in FIG. 1 . Table 1 shows a typical set of material parameters for a sample calculation.
TABLE 1
Layer thickness and material properties used to develop a sample
hybrid slab FEM. The Young's modulus for the SiO 2 and HR
coating layers were estimated to be equivalent to fused silica.
Young's
Thermal Conductivity
Modulus
Material
Thickness (mm)
(W/mm × ° C.)
(N/mm 2 )
Copper
1.0
0.391
117,200
Indium
0.0508
0.0818
10,600
HR coating
0.0041
0.001171
73,000
SiO 2
0.0035
0.00070
73,000
Yb:YAG
0.10 to 0.70
0.0073 at −50° C. to
280,000
0.0057 at +51° C.
YAG
4.5
0.0145 at −47° C. to
280,000
0.0095 at +49° C.
Stresses and temperatures were calculated in three dimensions for the composite slab for various deposited energy densities and layer thicknesses. Energy density refers to the net heat deposited in the material after pump absorption and Yb ion fluorescence. Three dimensional plots were then obtained for each case that showed thermal and stress gradients through the slab. By compiling the results of multiple runs we were able to observe how variations in energy density and layer thickness determined the maximum temperatures and stresses in the material. FIG. 2 shows how the maximum temperature and stress in the Yb:YAG layer varies with changing Yb:YAG layer thickness for a set of cases that assume a 1.05 mm diameter pump beam and a heat deposition of 5.3 W/TIR spot. The top of the slab is assumed to be surrounded by dry nitrogen gas at a temperature of 25° C. The far boundary of the copper heatsink is assumed to be held at a fixed temperature of 20° C.
For the FIG. 2 case shown, the maximum temperature increases as the Yb:YAG layer thickness increases since the entry face of the slab is farther from the heat sink. As shown, the temperature gradient across the slab can be as large as ˜100° C. since the heat sink is held at −20° C. The maximum stress in the material reaches a peak for a Yb: YAG layer thickness of ˜0.35 mm. As the Yb: YAG layer thickness increases the maximum stress decreases since the heat is spread out over a larger volume. In these cases the point of maximum stress physically corresponds to the spot of maximum temperature in the slab.
In FIG. 2, the graph plots maximum temperature and stresses in the Yb:YAG layer of a hybrid slab gain medium as a function of Yb: YAG layer thickness. The set of cases assumes a 1.05 mm diameter pump beam and 5.3 W of heat deposited in each pump spot. The boundary conditions assume that the copper heatsink is held at −20° C. and the top of the slab is exposed to dry nitrogen at +25° C.
The limiting thermal barrier for these cases is the SiO 2 and HR coating layers as these low conductivity coatings, despite being very thin, delay thermal transport. Table 1 shows the change in temperatures and stresses across the layers of the slab for the case of a 1.5 mm diameter pump beam, a Yb:YAG thickness of 0.2 mm and 4.0 W of heat per pumped spot. The values shown are divided by the thickness of the layers and are a measure of the change in temperature and stress per millimeter. The Yb:YAG layer is not shown because it is the loaded layer and has a peak temperature and stress in the middle of its layer.
TABLE 1
Changes in temperature and stresses across the layers of the
hybrid slab. The case assumes a 1.5 mm diameter pump beam,
a Yb:YAG thickness of 0.2 mm and 4.0 W of heat per pumped spot.
Temperature change across
Stress change across layer
Layer
layer (° C./mm)
(MPa/mm)
Copper
2.0
41
Indium
18.5
85
HR coating
1,317
2,293
SiO 2 coating
2,200
1,037
Undoped YAG
3.2
14
Table 1 clearly shows that the relatively low thermal conductivity of the SiO 2 and HR coatings have a very strong effect of the overall performance of the slab.
FIG. 3 shows a hybrid slab laser where the pump source 300 stimulates a carrier beam 301 to lasing in the active area 105 bound by a mirror 110 and hybrid slab 300 like the slab of FIG. 1 .
Our design goal was to design multi-pass disk and slab gain media which would allow us to absorb almost all of the available pump power while keeping the gain media as thin as possible to minimize thermal effects.
As previously discussed, the hybrid slab geometry was conceived as a way to retain most of the disk laser advantages while potentially offering a higher damage threshold. This is one potential route to enabling high pulse energy laser operation. FIG. 3 shows a schematic of the hybrid slab pump geometry as originally developed. Multiple lasing spots are possible depending on the length of the slab. Unpumped regions between pumped spots are lossy areas that absorb 1.03 μm light. This supplies a natural defense against parasitic oscillations. The laser can be pumped through the top surface (shown) as with the disk laser or collinearly with the laser beam (i.e. through the Brewster faces). This permits excellent pump and laser pump overlap with little pump light “wasted” in nonlasing regions of the slab. In either case, fiber coupled diodes can be used to maximize pump brightness.
Alternatively, the entire Yb doped region could be illuminated through the top face or from the side. This would allow the use of bar diode arrays (substantially cheaper than fiber coupled diodes) for pumping the slab. A disadvantage of this approach is that the entire active region of the slab is pumped (as with side-pumped rods or traditional slabs) so that most of the pump energy is deposited in regions of the hybrid slab that do not contribute to TEM 00 laser output. Presumably, this would result in the generation of a non-TEM 00 rectangular output beam. A second disadvantage with this approach is that it is conducive to parasitic oscillations. Although, as with traditional slab lasers, this deleterious effect can be combated by frustrating reflections in directions other than those established by the TIR beam path.
FIG. 3 shows a side view of the hybrid slab laser gain medium. The laser is pumped through the top face as with the disk laser.
Slabs were fabricated out of undoped YAG and had overall dimensions of 14.5 mm long (top surface) by 8 mm wide and 4.75 mm high. This allowed one TIR spot in each slab. A slab containing only one TIR spot was sufficient to demonstrate the feasibility of the hybrid slab concept and much less expensive to fabricate than a longer slab. A 250 μm thick, 15 wt % Yb doped YAG wafer was diffusion bonded to each slab as shown in FIG. 3 . Therefore, the hybrid slab had an overall height of 5 mm. The top or open face of the slab was antireflection coated at the pump wavelength and the bottom surface was coated as shown in FIG. 3 . The ends of the slab were Brewster-cut, as shown in the figures. The slabs were mechanically pressed onto a heat sink using the same technique used to mount disks. An indium foil was placed between the heat sink and slab, prior to pressing, t act as a ductile “solder” and to improve thermal conductivity across the boundary. Inspection of the mounted slab using a HeNe laser light source and crossed polarizers (to check for birefringence) indicated very little stress birefringence and low overall transmission distortions (<λ/2).
A hybrid slab laser was demonstrated using a short, linear cavity design resonator. The slab was pumped through the top face as shown in FIG. 3 . With 45 W of absorbed pump power we were able to produce 7.22 W of multi-mode (not TEM 00 ) laser output. Under these operating conditions the laser displayed a 27% absorbed power slope efficiency and operated 2.5 times above threshold. Thermal effects that distorted the pump and laser beam were quite noticeable at this pump power level. At higher pump powers further optical distortions prevented us from extracting more power. These distortions disrupted the spatial quality of both the pump and laser beams and caused the Yb:YAG laser beam to depolarize. It was hypothesized that even though the absolute thermal gradients in the slab were small, <12° C., that the relatively long optical path lengths in the slab (relative to a disk laser) resulted in large cumulative wavefront phase distortions.
The slab laser was operated using physically short resonators. We were not able to construct longer resonators because of the strong thermal lens that was created in the slab and our limited selection of cavity optics. Therefore, we were not able to build resonators long enough to enable insertion of the acousto-optic Q-switch and we did not demonstrate pulsed operation.
Significant variations in lasing performance were found depending on what part of the slab was lased. This indicates that thermal contact between the heat sink and the slab (or disk) may not have been uniform across the laser gain medium. Additionally, by modulating the pump beam and using a cw HeNe laser beam as a probe we observed that it took approximately 5 msec for localized heating in the slab to severely distort the probe beam. We also observed that this distortion lased for approximately 500 msec after the pump beam was turned off. These time durations are characteristic of processes involving thermal diffusion.
While the invention has been described in its presently preferred embodiment, it is understood that the words which have been used are words of description rather than words of limitation and that changes within the purview of the appended claims may be made without departing from the scope and spirit of the invention in its broader aspects.
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A hybrid slab laser is made using a slab of active laser material, for instance Yb:YAG, capped by a nonactive material, for instance undoped YAG or sapphire. The two materials are bonded together, for instance by diffusion bonding. The composite slab is then cut and polished to serve as a laser gain module. The slab can be Brewster-cut or flat-flat and antireflection coated on the ends. Alternatively, the nonactive material can be sandwiched between two active regions. The slab is pumped from the top face like a disk laser or from the end like a longitudinally pumped slab. The slab could also be side-pumped using close coupled diodes. The preferred pumping mechanism depends on the pump source used. The slab generates or amplifies a laser beam that is longitudinally coupled into the device through the end (possibly Brewster-cut) surfaces. The laser beam bounces via total internal reflection within the slab passing one or more times through the active part(s) of the medium. The active region can vary in thickness. The thickness is chosen to minimize thermal and/or stress gradients in the material.
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TECHNICAL FIELD
[0001] The present invention relates to computer systems. More particularly, the invention aims to improve the management of the random access memory (RAM) associated with the processors of computer systems, in order to ensure better performance in the execution of computer programs by the system.
TECHNOLOGICAL BACKGROUND
[0002] The performance of a computer system depends in particular on the performance of its processor (particularly its computational speed) and on the performance of the random access memory it uses to carry out the operations related to the execution of the instructions it is executing (in particular the memory read and write access times).
[0003] In communication systems for example, very high computational performance is expected while maintaining a limited cost and the shortest possible development time for the communication system.
[0004] The types of performance expected include the possibility of implementing real-time functionalities, such as for example the management of communication streams with increasingly large volumes of data to be processed. The implementation of these functionalities, however, must not adversely impact the implementation of other functionalities by the communication system. These real-time functionalities require significant computational resources because they involve the processing of a large amount of data within a minimum amount of time.
[0005] One solution consists of dedicating a processor to each type of functionality: one processor for real-time applications, and one processor for the other applications. This solution has the advantage of providing access to a large amount of computational power for running all the applications.
[0006] This solution significantly increases the cost of the communication system, however.
[0007] In addition, when it involves incorporating new real-time features into an existing hardware system that has only one processor, this solution is not a real possibility because it involves completely revising the system structure, which has a cost and involves a long development period.
[0008] Another solution consists of increasing the size of the primary memory cache (called the “L1 cache” by persons skilled in the art) in order to dedicate one part of the cache to real-time applications and the other part to the other applications.
[0009] It is thus possible to prepare a large volume of data and make them available to the processor very quickly. In fact, by having the data accessible in this cache, the number of instructions needed to obtain the memory from other memories is reduced.
[0010] However, this solution involves increasing the size of the components on the silicon of the chip in which the system is implanted. As a corollary, this solution implies a lower clock rate for the system.
[0011] In addition, there is a limit to how much the size of the L1 cache can be increased, beyond which the gain in computational speed becomes insignificant because the number of instructions for fetching specific data from the L1 cache becomes too high.
SUMMARY OF THE INVENTION
[0012] There is therefore a need to improve the performance of computer systems while ensuring a limited cost and a reasonable development period, particularly when adding new functionalities to an existing platform.
[0013] For this purpose, a first aspect of the invention proposes a method for managing random access memory in a computer system, with the computer system comprising a processor, a first static random access memory, and a second dynamic random access memory, said process comprising the steps of:
[0014] receiving at least one instruction to be executed by the processor,
[0015] determining a priority level for the execution of the instruction by the processor, and
[0016] loading the instruction into the first memory, for execution by the processor if its priority level indicates that this is a high priority instruction, or if not
[0017] loading the instruction into the second memory, for execution by the processor.
[0018] The memories in question can be different than a cache.
[0019] Dynamic random access memory can be defined as random access memory requiring the refreshing of data. Static random access memory can be defined as random access memory not requiring any refresh.
[0020] Static random access memory is generally very fast but has a large silicon footprint. Dynamic random access memory is generally cheaper and less voluminous.
[0021] For example, the first random access memory is SCRAM (“Static Column Random Access Memory”), and the second random access memory is SDRAM (“Synchronous Dynamic Random Access Memory”).
[0022] SCRAM memory allows fast loading and unloading of instructions. In addition, SCRAM memory can easily be included in different types of circuits.
[0023] For example, the first static random access memory is memory internal to the processor, and the second dynamic random access memory is memory external to the processor. Having the memory close to the processor allows faster data transfers.
[0024] According to the invention, instructions are dynamically loaded into and unloaded from the first and second random access memory according to the priority that is assigned to the instructions.
[0025] The priority assigned to the instructions can depend on the context of the execution of a particular function by the computer system.
[0026] As a further example, the priority given to the instructions can come from the fact that these are instructions from computer code often used by a particular function.
[0027] The random access memory management of the invention allows increasing the computational power of the processor, and accelerating the execution of computer programs without extra costs in hardware development.
[0028] In some embodiments, the method additionally comprises the steps of:
[0029] receiving a set of instructions to be executed by the processor,
[0030] defining, within the set of instructions, a first and a second subset of instructions as a function of a priority level for execution by the processor determined respectively for the instructions, with the first subset comprising priority instructions whose execution priority level indicates that they have priority over the instructions of the second subset,
[0031] loading instructions of the first subset into the first memory for their execution by the processor, and
[0032] loading instructions of the second subset into the second memory for their execution by the processor.
[0033] In some embodiments, the instructions are loaded/unloaded between the first and second random access memory as their priority level changes.
[0034] Thus, depending on the context of the processor utilization, an instruction can change from a high priority level to a lower priority level or vice versa.
[0035] For example, an instruction can be found to have a lower priority than a newly called instruction to be executed by the processor.
[0036] It can be arranged that a set of instructions associated with the implementation of a function by the computer system is identified.
[0037] For example, depending on the “use case”, certain instructions which are used often can be given preference.
[0038] For example, when a telecommunications application is started up, the execution of the application can be accelerated by giving priority to the instructions frequently executed by the application, making them available to the processor in the static random access memory (SCRAM memory for example).
[0039] In some embodiments, the instructions are associated with at least one priority parameter, and the determination of the priority level of the instructions is based on their respective priority parameters.
[0040] This allows, for example, rapid determination of the priority level of an instruction, by reading from a table comprising the parameter.
[0041] For example, a priority parameter is representative of a processor load savings.
[0042] For example, to determine this load savings, the number of clock cycles per instruction executed by the processor when the instruction is stored in the first and second memory is compared.
[0043] For example, a priority parameter is representative of the amount of memory occupied by the instruction.
[0044] In some embodiments, the storage of instructions in the first memory is determined by compromising between the size of the instructions and the processor load savings that they would provide.
[0045] As the size of the static random access memory is limited, its optimum usage depends on a comparison of the amount of available memory and the processor load savings provided by storing instructions within it.
[0046] For example, the parameter associated with the instructions has a fixed value.
[0047] A table can be provided that stores, for each instruction, the parameters associated with it.
[0048] As a further example, the parameter is associated with the instructions dynamically, based on a learning algorithm which assigns a priority parameter based on a processor load savings measurement associated with each instruction.
[0049] To establish the parameter dynamically, a dynamic measurement of the number of operations necessary to execute the instruction can be provided. In another variation, there can be dynamic access to the processor load level at each moment in the execution of the instruction.
[0050] In some embodiments, the storage of instructions in the first memory is done according to a learning algorithm that also optimizes usage of the first memory.
[0051] For example, the algorithm is an adapting algorithm and can identify an association of instructions which, when stored together in the static random access memory, provide good optimization of the static random access memory.
[0052] Other aspects of the invention also allow for:
[0053] a computer program comprising instructions for implementing a method according to the invention, when the program is executed by a resource manager of a computer system;
[0054] a computer system according to the invention; and
[0055] an integrated circuit comprising a system according to the invention.
[0056] The computer program, the system, and the integrated circuit present at least the same advantages as those provided by the process according to the first aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] Other features and advantages of the invention will become apparent from reading the following description. This description is purely illustrative and is to be read in light of the attached drawings, in which:
[0058] FIG. 1 schematically illustrates a processing unit structure of a computer system according to an embodiment of the invention;
[0059] FIGS. 2 a and 2 b illustrate the architecture of a system according to embodiments of the invention;
[0060] FIG. 3 illustrates a resource manager according to an embodiment of the invention;
[0061] FIG. 4 illustrates the management of random access memory according to an embodiment;
[0062] FIG. 5 is a flow chart of steps implemented in a method according to an embodiment of the invention;
[0063] FIG. 6 is a flow chart of steps implemented in a method for setting a priority parameter according to an embodiment of the invention; and
[0064] FIG. 7 is a flow chart of steps implemented in a method for setting a priority parameter according to another embodiment of the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0065] A processing unit structure of a computer system is described very schematically, with reference to FIG. 1 .
[0066] In this structure, there is a processor 10 in charge of executing more or less basic instructions in the context of the more general execution of a computer program.
[0067] The processor 10 has different types of memory available for this purpose.
[0068] It has several cache memories available to it. This type of memory is used to store data temporarily that are useful for the execution of the instructions. This type of memory can store data to be processed such as the operands of operations to be executed by the processor, or the identification of operations to be performed. This memory has very good performance in terms of access time, and is used for copying the data used to bring them close to the processor.
[0069] Among such cache memory is the “L1” cache 11. This is the cache closest to the processor, and is also the highest performance memory in terms of access time. This type of memory is generally very costly and therefore its size is generally limited. Also among such cache memory is the static random access memory 12 . This random access memory also has very good performance, although inferior to that of the L1 cache. The cost of this type of memory allows the possibility of providing more of it than in the L1 cache.
[0070] The processor 10 also has dynamic random access memory 13 available to it. This type of random access memory generally requires regularly refreshing the data, but takes up very little area on the silicon and is inexpensive because its structure is very simple.
[0071] Lastly, the processing unit has read-only memory 14 for storing data in a lasting manner.
[0072] In order to implement a computer program for example stored in the read-only memory 14 , the processing unit copies certain parts of the computer code into the random access memory or cache in order to speed up the execution of the program.
[0073] It is proposed to optimize the use of the random access memory available to the processor in order to further accelerate the execution of the program, in particular the management of the static 12 and dynamic 13 random access memories.
[0074] To illustrate the proposed optimization, a context for implementing the invention is described with reference to FIGS. 2 a and 2 b.
[0075] In FIG. 2 a , a dynamic random access memory 20 and a static random access memory 21 are represented.
[0076] It is assumed that the information system must execute a computer program. For this purpose, it knows about a certain number of instructions (or parts of code) that will be executed. These instructions are identified in a virtual memory 22 . This virtual memory represents a table which comprises the addresses in the read-only memory where the instructions are stored.
[0077] A memory management unit MMU 23 is in charge of translating virtual addresses into physical addresses in the random access memory at the appropriate moment. This unit handles such translations for the different types of memory in the system (RAM or ROM).
[0078] In the example illustrated in FIG. 2 a , among the instructions to be executed there is an instruction for managing a communication on a USB port 220 , an instruction for video encoding 221 , an instruction for video decoding 222 , an instruction for audio encoding 223 , an instruction for audio decoding 224 , an instruction for managing a WiFi communication 225 , an instruction for managing a stream of data 226 , and an instruction for implementing telecommunications 227 .
[0079] In the example illustrated by FIG. 2 a , it is assumed that the processing unit is to implement the reception of a video stream.
[0080] For this purpose, according to the invention, the instructions critical to performing said reception are identified in the virtual memory. The critical applications are for example the instructions which if their execution was accelerated would allow performing the video stream reception function faster.
[0081] Then the instructions for video decoding 222 , audio decoding 224 , data stream management 226 , and implementing communications 227 are identified.
[0082] Next the instructions 222 , 224 , 226 , and 227 are stored in the static random access memory 21 , and the other instructions in the dynamic random access memory 20 .
[0083] The reception of the video stream, which in this example is judged to have priority, is thus carried out while benefiting from the performance of the static random access memory, while the other functionalities carried out by the processing unit only use the dynamic random access memory.
[0084] This accelerates the execution of the video stream reception.
[0085] In another example illustrated in FIG. 2 b , the same elements are found as were described with reference to FIG. 2 a.
[0086] This time it is assumed that the computer system is to implement a modem function on a USB port.
[0087] The critical instructions for implementing this function are identified. In the example illustrated by FIG. 2 b , it is assumed that the critical instructions are the instructions 220 and 227 .
[0088] The instructions are then loaded into the memory 21 , while the instructions 222 , 224 , and 226 are unloaded from the memory 21 and loaded into the memory 20 .
[0089] This accelerates the execution of the modem function on the USB port, which in this example is considered to have priority over the video stream reception function which previously had priority.
[0090] The management of the random access memory can be executed by a resource manager.
[0091] Such a resource manager is represented in FIG. 3 .
[0092] The resource manager 30 is connected via an interface 31 to various resources 32 and 33 . These resources are, for example, files storing the computer code for functions such as telecommunications, multimedia, connectivity, or other functions. For example, the instructions for the examples in FIGS. 2 a and 2 b come from these resources.
[0093] The resource manager is in charge of storing, according to the computer program to be executed, the instructions for the resources into the static 34 and dynamic 35 memories.
[0094] For this purpose, it has access to a Direct Memory Access Unit 36 and a Memory Management Unit 37 .
[0095] As has already been mentioned, the Memory Management Unit knows the virtual memory addresses of the instructions to be executed and is in charge of translating these virtual addresses into the physical addresses in the memories 34 and 35 . The Direct Memory Access Unit handles the copying of data into the dynamic random access memory and static random access memory, as well as the exchange of data between these two memories.
[0096] The resource manager 30 controls the Direct Memory Access Unit 36 and Memory Management Unit 37 via the respective drivers 38 and 39 .
[0097] The random access memory management is illustrated according to one embodiment, with reference to FIG. 4 .
[0098] The table 40 represents a table showing the correspondence between four groups of instructions I 1 , I 2 , I 3 , and I 4 (INSTR column) and their respectively associated set of priority parameters (PARAM column).
[0099] With each instruction is associated a size in kilobits for example (under the SIZ column), and a processor load savings as a percentage for example (under the % SAV column).
[0100] To obtain the processor load savings parameter, one can, for example, calculate the ratio of the difference between the execution time for the instruction when the instruction is executed from the dynamic RAM and when it is executed from the static RAM on the one hand, and of the execution time for the instruction when the instruction is executed from the dynamic RAM on the other.
[0101] As another example, one can calculate the ratio of the difference between the number of operations for the processor to execute the instruction when the instruction is executed from the dynamic RAM and when it is executed from the static RAM on the one hand, and of the number of operations for the processor to execute the instruction from the dynamic RAM on the other.
[0102] Thus the group of instructions I 1 has a size of 19 kB and allows a processor load savings of 5%, the group of instructions I 2 has a size of 5 kB and allows a processor load savings of 3%, the group of instructions I 3 has a size of 4 kB and allows a processor load savings of 2%, and the group of instructions I 4 has a size of 5 kB and allows a processor load savings of 2%.
[0103] It is assumed that there are 20 kB of static RAM available.
[0104] The table 41 represents a sequence of operations for optimizing the static RAM according to one embodiment.
[0105] At time t 1 , the execution of the group of instructions I 1 is requested (RQST column). It is assumed that the static RAM and the dynamic RAM are empty (columns SCRAM SIZ and SDRAM SIZ). Optimization has not yet begun and therefore the processor load savings is still zero (% SAV column). Alternatively, one can initially store all the instructions in dynamic RAM, and in this case only the static RAM is empty.
[0106] As the static RAM is empty, and the group of instructions I 1 is of a size that can be stored in the static RAM and thus reduce the processor load, this instruction is loaded into the static RAM (OPER column).
[0107] At time t 2 , the execution of the group of instructions I 2 is requested.
[0108] This group of instructions has a size of 5 kB. However, only 1 kB remains free in the static RAM. Therefore the groups of instructions I 1 and I 2 are examined to see which provides the greatest processor load savings. In this example it is the group I 1 .
[0109] The group of instructions I 1 is therefore kept in the static RAM, and the group of instructions I 2 is stored in the dynamic RAM. Then the group of instructions I 2 is copied into the dynamic RAM and the MMU is consequently reconfigured. If the groups of instructions were stored by default in the dynamic RAM as mentioned above, nothing is done.
[0110] At time t 3 , the execution of the instruction I 3 is requested.
[0111] This group of instructions has a size of 4 kB. However, only 1 kB remains free in the static RAM. Therefore the groups of instructions I 1 and I 3 are examined to see which provides the greatest processing load savings. In this example it is the group I 1 .
[0112] Also examined is whether storing the groups of instructions I 2 and I 3 together in the static RAM instead of the group of instructions I 1 would provide better load savings. In this example such is not the case, because storing these two instructions provides a processor load savings of 5% which is exactly the same savings provided by storing the group of instructions I 1 in the static RAM.
[0113] Even if the two instructions occupied less space, it would not be advantageous to store them in the static RAM because the operation of moving the groups of instructions I 1 and I 2 would increase the processor load.
[0114] Therefore the group of instructions I 1 is kept in the static RAM, and the group of instructions I 3 is stored in the dynamic RAM.
[0115] At time t 4 , the execution of the group of instructions I 4 is requested.
[0116] This group of instructions has a size of 5 kB. However, only 1 kB remains free in the static RAM. Therefore the groups of instructions I 1 and I 4 are examined to see which provides the greatest processor load savings. In this example it is the group I 1 .
[0117] Also examined is whether storing several groups of instructions from among the groups I 2 , I 3 and I 4 together in the static RAM instead of group I 1 would provide better load savings. In this example such is the case, because storing these three groups provides a processor load savings of 7% (3+2+2) which is greater than the savings provided by storing the group I 1 in the static RAM, which is 5%. In addition, the size of the three groups combined is 14 kB which can be accepted by the static RAM.
[0118] It is assumed that the data transfers between the memories do not adversely impact the gain in processor load savings. The group of instructions I 1 is therefore moved from the static RAM to the dynamic RAM, the groups of instructions I 2 and I are moved from the dynamic RAM to the static RAM, and the group of instructions I is stored in the static RAM.
[0119] At time t 5 we therefore have instructions stored in the static RAM such that the groups of instructions allow an optimum savings of the processor load.
[0120] The steps performed in a method of one embodiment are presented with reference to FIG. 5 .
[0121] In this embodiment, the use of the static RAM is optimized according to an instruction size parameter and a processor load savings parameter, such as in the example described with reference to FIG. 4 .
[0122] During a first step S 500 , an instruction is received to be executed by the processor. It is attempted to determine whether this instruction is to be loaded into the static RAM or the dynamic RAM.
[0123] During the step S 501 a parameter associated with the instruction is determined, representative of the size this instruction occupies in memory. For example, this parameter is read from a table such as was described with reference to FIG. 4 .
[0124] During the test T 502 , it is established whether the parameter representative of the size this instruction occupies in memory allows its direct storage in the static RAM. If such is the case, for example if there is enough space in the static RAM, the instruction is stored in the static RAM during the step S 503 .
[0125] Otherwise, for example if there is not enough space in the static RAM, in the step S 504 a parameter associated with the instruction is determined, representative of a processor load savings offered by storing the instruction in the static RAM. For example, this parameter is read from a table such as was described with reference to FIG. 4 .
[0126] Then, during the test T 505 , it is determined whether the instruction has a better parameter representative of a processor load savings than another instruction already stored in the static RAM.
[0127] If such is the case, the instruction already present in the static RAM is unloaded during the step S 507 , then it is stored in the dynamic RAM during the step S 508 . In addition, the instruction received during the step S 500 is stored in the static RAM during the step S 509 .
[0128] If the test in the step T 505 is negative, the process continues on to the test T 510 in which it is determined whether instructions exist, in the dynamic RAM, whose parameters representative of a processor load savings when added together offer a better parameter representative of a processor load savings than the one for another instruction already stored in the static RAM.
[0129] If such is the case, the instruction is unloaded from the static RAM during the step S 512 then it is stored in the dynamic RAM during the step S 513 .
[0130] Next, the instructions found during the step T 505 are unloaded from the dynamic RAM during the step S 514 . These instructions are then stored in the static RAM during the step S 515 .
[0131] If the test in the step T 510 is negative, the instruction received during the step S 500 is stored in the dynamic RAM during the step S 511 .
[0132] Once the steps S 515 , S 511 , S 503 and S 509 are completed, the process returns to the step S 500 to receive a new instruction to be executed.
[0133] To determine the parameter representative of a processor load savings or to update a table of parameters as was described with reference to FIG. 4 , a learning algorithm can be implemented.
[0134] Such an algorithm is now described, with reference to FIG. 6 .
[0135] During the initial step S 60 an instruction to be executed is identified, then during the step S 61 the execution time by the processor is measured (or the number of operations for the processor to execute the instruction, as already mentioned above).
[0136] Depending on whether the instruction was executed from the static or the dynamic RAM (test T 62 ), a value for the execution time in the static RAM (step S 63 ) and in the dynamic RAM (step S 64 ) is updated. For example, the execution time is an average of the time for the processor to execute the instruction.
[0137] Then, during the step S 65 , the parameter representative of a processor load savings is determined. For example, the ratio is determined of the difference between the values obtained during steps S 63 and S 64 on the one hand, and of the value obtained during the step S 64 on the other. To find this ratio, one can verify beforehand that the values were obtained under the same conditions, for example the instructions were executed in the same context (for example while running the same computer program), or if the values obtained are averages, that these averages were calculated using the same number of values.
[0138] The steps of a method according to another embodiment are now described with reference to FIG. 7 .
[0139] In this embodiment, the instructions are stored in the static RAM or the dynamic RAM depending on a function with which they are associated.
[0140] Thus, if giving priority to this function is desired, all the instructions associated with it are stored in the static RAM.
[0141] During the step S 70 , a function or code of a computer program is identified. For example, the execution of this function is to be accelerated.
[0142] Then, during the step S 71 , a set of instructions associated with this function is identified.
[0143] The identified instructions are then stored in the static RAM during the step S 72 .
[0144] During the step S 73 , it is detected that the function has been executed, or that the function is no longer to be accelerated. The instructions are then unloaded from the static RAM to be for example stored in the dynamic RAM. As a further example, the instructions are simply replaced with other higher priority instructions.
[0145] A computer program of the invention can be realized according to a general algorithm deduced from the general flowchart in FIGS. 5 , 6 , and/or 7 , and the present description.
[0146] An integrated circuit of the invention can be realized by techniques known to a person skilled in the art, in order to be configured to implement a process of the invention. For example, a system of the invention can be realized in an integrated circuit in the form of a System on Chip (SoC).
[0147] For example, a system of the invention can be implanted in a terminal or other communication equipment to allow better communication performance by these devices.
[0148] The invention has been described and illustrated in the present detailed description and in the Figures. The invention is not limited to the embodiments presented here. Other variations and embodiments can be deduced and implemented by a person of ordinary skill in the art upon reading the present description and the attached Figures.
[0149] In the claims, the term “comprise” does not exclude other elements or other steps. The indefinite article “a” does not exclude the plural. A single processor or several others together can be used to implement the invention. The various characteristics presented and/or claimed can advantageously be combined. Their presence in the description or in different dependent claims does not exclude this possibility. The reference labels are not to be considered as limiting the scope of the invention.
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The invention proposes a method for managing random access memory in a computer system, with said computer system comprising a processor, a first static random access memory, and a second dynamic random access memory, the method comprising the steps of:—receiving at least one instruction to be executed by the processor,—determining a priority level for the execution of the instruction by the processor, and—loading the instruction into the first memory for its execution by the processor if its priority level indicates that it is a high priority instruction, or if not—loading the instruction into the second memory for its execution by the processor.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fastener. The fastener has particular utility in securing a sheet of flexible material in a desired position, securing one such sheet to another, or securing a desired object to such a sheet.
2. Description of Related Information
It is frequently desirable to securely hold a sheet of plastic, canvas, waterproof tarpaulin, fabric, or other material in a particular location. For example, fastening means are desirable for securing a tent to its stakes.
It is also desirable on occasion to secure two or more sheets to each other or to secure an object to a sheet, such as a lamp hanging within a tent, or a weight hanging from the side of a sheet. In certain applications, it is also desirable to prevent rotation of a sheet of material relative to a fastener or stationary object since rotation may initiate stretching or tearing of the sheet, and may disturb items covered by the sheet.
In the past, a variety of devices were used for fastening sheets to other objects, including devices that employed collar-retainer systems. In a collar-retainer system, the retainer may be alternately engaged or disengaged within the collar. By placing the sheet between the collar and retainer before engaging the two, the collar-retainer system is secured to the sheet. Two sheets may be attached to one another by placing both within a collar-retainer. To secure the sheet to another object, collar-retainer systems have employed hooks or slots integrally attached to the collar.
In a collar-retainer system, there must be sufficient clearance or flexibility between the retainer and collar to allow one or more sheets to be placed therebetween. However, the retainer and collar must also form a tight enough connection to prevent the retainer and collar from disengaging under stress. Devices employed in the past suffered from collar-retainer combinations that were too tight, resulting in difficulty of use and an increased risk of contact part fatigue, or too loose, resulting in a lack of dependability due to collar-retainer separation under stress.
In addition, fasteners in the past featured circular retainer-collar combinations that allowed relative rotation. Those retainer-collar systems that did not employ circular combinations employed collars having oddly shaped protrusions subject to fatigue failure under repeated stress. Finally, fasteners in the past used hooks or slots that suffered from limited versatility due to their size--and means--specific nature, and due to inaccessible connection points.
A need exists, therefore, for a fastener that provides a tight fit between the retainer and the collar but allows placement of a sheet therebetween, that is quick and easy to engage and disengage, and that is relatively free of easily fatigued protrusions. A need also exists for a fastener that is versatile enough to be securely attached to hooks, ropes, screws, nails, conventional tent stakes, and a variety of other securing means. Finally, a need exists for a fastener that can be secured in a given orientation and that will resist rotation therefrom.
SUMMARY OF THE INVENTION
The apparatus of the present invention overcomes the above-mentioned disadvantages and drawbacks which are characteristic of the related information. In addition, the apparatus of the present invention includes a collar and a retainer that provide an increasingly tightening fit therebetween when a sheet of material is secured to the fastener and under tension.
According to the apparatus of the present invention, the retainer and collar each have an essentially triangular configuration. In a preferred embodiment of the present invention, the collar comprises a triangular frame and the retainer comprises a triangular frame having a central hub. The retainer and collar are equiangular triangles, the collar triangle having a greater height than the retainer triangle. In an alternate preferred embodiment, the hub may further comprise a ballast weight.
In another preferred embodiment, the retainer comprises a groove defined by upper and lower flanges along its outer circumference. The groove is adapted to snugly receive the collar frame. When the retainer is engaged within the collar, two legs of the collar and retainer mate, while a gap is formed between the remaining legs. At the remaining legs, a smooth tongue protrudes inwardly from the collar frame across the gap and into the retainer groove.
The retainer and collar are engaged and disengaged by flexing the collar frame. The collar frame or retainer flanges may be elastically deformed within a range sufficient to allow one of the retainer flanges to be urged around the tongue so that the tongue is received within the groove.
In yet another preferred embodiment of the present invention, the collar frame also includes a frame extension extending from one leg of the frame. The frame extension comprises a substantially triangular portion having a slot for connecting to hooks, rope, stakes, or other means. Preferably, the slot is T-shaped to allow a conventional tent stake to be driven therethrough. In another preferred embodiment, the T-shaped slot has a circular slot superimposed thereon, to allow the fastener to be hooked over a nail or bolt. In this embodiment, the head of the nail or bolt is received through the circular portion of the slot, and, depending on the direction of applied tension, the nail shaft proceeds down the trunk or one of the respective arms of the T-shaped slot.
Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a preferred embodiment of the fastener of the present invention in a disengaged condition;
FIG. 2 is a perspective view of the fastener shown in FIG. 1 in an engaged condition; and
FIG. 3 is a cross-section view of the fastener shown in FIG. 2 taken along line 3--3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly to FIG. 1, a preferred embodiment of the fastener of the present invention is shown and generally designated by the reference numeral 10.
The fastener 10 includes a flexible plastic collar 12 and a plastic retainer 14. The retainer 14 comprises a substantially triangular frame 16 surrounding a hub 18, and having a groove 20 defined by upper and lower flanges 22 and 24 disposed around the outer circumference of the retainer frame 16. In another preferred embodiment, a ballast weight (not shown) may be attached to the hub 18 using conventional means. In still another embodiment, the hub 18 may be deleted from the retainer 14.
The collar 12 comprises a substantially triangular resilient flexible frame 26, having a primary leg 28 and two secondary legs 30. As shown in FIG. 3, the secondary legs 30 have a cylindrical cross-section. A tongue 32 protrudes inwardly from the primary leg 28. The inner faces 34 of the secondary legs 30, and the tip 36 of the tongue 32 are adapted to be received within the groove 20 of the retainer 14 when the retainer 14 is placed within the collar 12. In a preferred embodiment, the tongue 32 is smoothly contoured.
Those of ordinary skill in the art will recognize that a variety of tongue contours and shapes may be employed according to the present invention. Those of ordinary skill in the art will also recognize that the tongue 32 is not required if the collar and retainer are sufficiently resilient and flexible to allow the retainer to be popped in and out of the collar.
According to the preferred embodiment of the present invention, the collar 14 includes a collar extension 38 that is integrally attached to the primary leg 28 and protrudes outwardly therefrom. The preferred collar extension 38 is substantially triangular, so that the collar 12 has an overall parallelogram or diamond shape. The collar extension 38 comprises a slot 40 having a circular slot portion 42 superimposed on a substantially T-shaped slot portion 44.
Those of ordinary skill in the art will recognize that the shape of the slot 40 may be varied to suit the demands of the application, and that many conventional slot shapes may be employed. Those of ordinary skill will also recognize that the frame extension may extend from any leg, not necessarily the primary leg 28. Finally, those of ordinary skill in the art will recognize that a frame extension is not required where the fastener 10 is used as ballast or to secure two or more sheets to one another.
In operation of the preferred fastener where it is desired to secure a sheet in a desired location, one or more sheets of material 46 are placed over the retainer 14. The collar 12 is elastically flexed about the primary leg 28 to allow retainer 14 and the sheet 46 to be disposed within collar frame 26 such that the secondary legs 30 and the tongue 32 are disposed within the retainer groove 20.
Once the sheet 46 is secured to the fastener 10, the fastener 10 may be secured to a desired object. In the case of a tent stake, the stake is merely driven through the slot 40. In the case of a nail or bolt, a nail or bolt head may be received through the circular slot portion 42 and then urged into one of the legs of the T-shaped slot portion 44. In the case of a rope, a rope may be looped through the circular slot portion 42 and then urged into one of the legs of the T-shaped slot portion 44. Instead of being looped, the rope may also be tied into a knot of greater diameter than the circular slot portion 42 at one end to prevent the rope from slipping through the slot 40. The other end of the rope is then secured as desired.
While preferred embodiments of the invention have been shown and described, it will be understood by persons skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention which is defined by the following claims.
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A fastener comprising a retainer and a collar wherein one or more sheets of material may be secured between the retainer and collar, and wherein the fastener may be weighted or attached to a variety of objects.
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FIELD OF THE INVENTION
[0001] This invention pertains to a binding apparatus and, more specifically, to a binding apparatus that binds objects by winding adhesive tape around the object.
BACKGROUND OF THE INVENTION
[0002] A known method for binding and anchoring branches and vines of such horticultural and agricultural products as grapes, cucumbers, etc., onto splints-and stretched string, etc., includes the use of adhesive vinyl-type tape on the object to be bound with the winding of tape around it and then fastening the ends of the tape with a binding needle or staple. This method, however, creates a major problem in terms of environmental pollution because it leaves behind non-biodegradable vinyl, bonding needles and staples, all of which will remain intact for generations.
[0003] Alternatively, there is also a known method of using paper-based adhesive tape to wind the tape around a given object and to bind both ends of the adhesive tape. Using this method it is possible to solve the problem of environmental pollution because no binding needle or staple is used and the tape is made of paper, which is biodegradable. However, in methods using adhesive tape the vines and branches of the objects to be taped are wound with tape that provides some slack because the surface of the tape does not slide. Therefore, the objects are not tightly bound, inviting the problem in which the vines and branches easily become disengaged from the splints. It therefore becomes necessary to bind the vines and branches manually to create a firm bond.
[0004] The objective of this invention is to provide a binding apparatus that binds both ends of an adhesive tape around an object by firmly winding the tape around the object without allowing slack and without using binding needles or staples at either end of the tape.
[0005] Therefore, a need existed to provide a device and method to overcome the above problem.
SUMMARY OF THE INVENTION
[0006] To achieve the objective as described above, the binding apparatus of this invention consists of the following: The subject invention is an apparatus installed on a base plate, said invention having the following parts and characteristics: A tape-retaining section that contains a spool onto which the adhesive tape is wound, allowing it to turn freely; a section located at one end of the base plate that allows housing the object to be wound from the opening; a tape-end processing device that holds the tape from both ends or releases the free end of the tape located on the aforementioned aperture side from the housing section of the base plate; a plate that freely moves in a direct line from the aforementioned housing section of the base plate to the tape-retaining section, and an arm installed on the plate so that it can rotate freely; a plate-transfer device for moving the plate in a straight-line direction; an arm-turning device for the aforementioned arm to turn; a straight-line position-detection device that detects the position of the aforementioned plate; a turn position-detection device that detects the turning position of the aforementioned arm; a control device that controls the drive of the aforementioned plate-transfer device and the arm-turning device with the signals detected by the aforementioned straight line position-detection device and the aforementioned turn position-detection device.
[0007] The aforementioned device is designed to hold the free ends of the tape-end processing device while retaining the midsection of the tape between the free ends of the tape and the tape spool, using the tip section of the arm so that it can slide freely.
[0008] The control device drives the plate-transfer device and the arm-turning device, and winds the tape onto the object to be wound with tape stretched taut and by moving the midsection of the tape around the circumference of the object in the housing section, with (both ends of) the tape bound together. The arm then severs the midsection of the tape with the tape-processing device, and the free ends of the severed tape are held by the binding apparatus being characterized.
[0009] Because of this set up, the objects to be bound can be secured firmly because of the use of a non-adhesive tape used in a stretched state to wind the tape around the perimeter of the object to be bound.
[0010] The present invention is best understood by reference to the following detailed description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a drawing showing the exterior of this invention's embodiment.
[0012] FIG. 2 is a drawing that explains the structure and movement of one side of the interior of the embodiment.
[0013] FIG. 3 is a drawing that explains the structure and movement of one side of the interior of the embodiment.
[0014] FIG. 4 is a drawing that explains the structure and movement of one side of the interior of the embodiment.
[0015] FIG. 5 is a drawing that explains the structure and movement of one side of the interior of the embodiment.
[0016] FIG. 6 is a drawing that explains the structure and movement of one side of the interior of the embodiment.
[0017] FIG. 7 is a drawing that explains the structure and movement of one side of the interior of the embodiment.
[0018] FIG. 8 is an expanded drawing that explains the main sections and their movements of the embodiment.
[0019] FIG. 9 is an expanded drawing that explains the main sections and their movements of the embodiment.
[0020] FIG. 10 is an expanded drawing that explains the main sections and their movements of the embodiment.
[0021] FIG. 11 is an expanded drawing that explains the main sections and their movements of the embodiment.
[0022] FIG. 12 is an expanded drawing that explains the main sections and their movements of the embodiment.
[0023] FIG. 13 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0024] FIG. 14 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0025] FIG. 15 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0026] FIG. 16 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0027] FIG. 17 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0028] FIG. 18 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0029] FIG. 19 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0030] FIG. 20 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0031] FIG. 21 is a drawing that explains the structure and movement of the rear side of the interior of the embodiment.
[0032] FIG. 22 is an expanded drawing that explains the main sections and their movements of the embodiment.
[0033] FIG. 23 is a block diagram of the embodiment showing the circuit configuration.
[0034] Common reference numerals are used throughout the drawings and detailed description to indicate like elements.
DETAILED DESCRIPTION
[0035] The following illustrates the form of embodiment of this invention of a binding apparatus based on drawings: FIG. 1 shows the rough configuration of one form of the embodiment of this invention. In FIG. 1 , cover plates 2 and 3 are fixed parallel to the base plate 1 on both sides of the base plate. A cylindrical bearing 4 for that allows tape A to freely bind an object is located on the upper right-hand corner of the base plate 1 in the surface drawing of the base plate 1 .
[0036] In the wide section below the bearing 4 of the base plate 1 , there are two parallel slotted holes 5 and 6 running in the horizontal direction as shown in FIGS. 2 and 13 . As shown in FIG. 2 , pins 7 and 8 , being aligned with slotted hole 5 affix plate 10 so that the plate can slide freely in the horizontal direction on the same side as the bearing 1 on the base plate 1 . Additionally, axis 11 is aligned with slotted hole 6 and is attached to plate 10 so that it can turn freely.
[0037] As shown in FIG. 13 , the plate-transfer device for moving the plate 10 horizontally is installed on the rear surface of the base plate 1 . That is, on the back of the base plate 1 are located the motor 12 and the reduction gear device 13 , which reduces the revolution of the output axis (worm gear) 12 a.
[0038] The crank 16 is connected in a way that it freely turns at one end of the crank 15 , which turns together with output gear 14 , and the end section of crank 16 is attached to axis 11 so that it can turn freely. Therefore, as axis 11 moves along slotted hole 6 according to the revolutions of the motor 12 , the plate 10 moves sideways with the axis 11 . The position of the axis 11 , which moves along slotted hole 6 , is sensed by a contact type or a photoelectric-type detection device not shown in the drawing (but shown in FIG. 23 as 131 ) on the base plate 1 . Therefore, the position of plate 10 is sensed in the horizontal direction.
[0039] An arm-turning device that moves actuator arm 23 and guide arm 28 is installed on the plate 10 . That is, as shown in FIG. 2 , the plate 10 has a reduction gear device 21 that reduces the revolutions of the output axis (worm gear) 20 a and the motor 20 . Additionally, the output gear 22 is attached to axis 11 so that it can turn freely.
[0040] The actuator arm 23 , which turns in unison with the aforementioned output gear 22 , is attached to the axis 11 . The insert plate 24 and cutting plate 25 are affixed in parallel to the tip of the actuator arm 23 . Moreover, the guide arm 28 is installed on the axis 11 , overlapping the actuator arm 23 so that it can turn freely.
[0041] Several tape guide rollers 29 are installed on the tip and midsections of the guide arm 28 . The guide arm 28 is set to work clockwise (in FIG. 2 ) via the spring 30 locked onto the arm at one end, and is in contact with the stopper 26 of the actuator arm 23 .
[0042] The turn angle of the output gear 22 is sensed by the detection device (shown as 132 in FIG. 23 ), which is attached to the plate 10 but not shown.
[0043] The upper-left section of the base plate 1 (in FIG. 2 ) has a semicircular notch section 31 for housing the object to be bound. Additionally, a tape-processing device 32 for holding both ends of the tape and cutting it is located in the upper left-hand corner 1 a.
[0044] This tape-processing device 32 is configured in the following way: At the upper corner section la of the base plate 1 , flat plates 33 and 34 for cutting are arranged in the vertical direction and mutually parallel in the outside position, while the flat plate 35 for holding the tape in a vertical direction is located on the notch side 31 . Additionally, the wedge-action holding (pinch) plate 36 is attached to the upper corner section la by axis 37 so that it can turn freely between the flat plates 34 and 35 .
[0045] The wedge-action holding (pinch) plate 36 , as shown in FIG. 6 , has an L-shaped bent section 36 a as an extension, and a spring 38 is attached between this bent section 36 and the flat plate 33 . Therefore, the wedge-action holding (pinch) plate 36 is set to move counter-clockwise (in FIG. 6 ), centering on support axis 37 . As FIGS. 2 to 4 and FIG. 12 show, the tip 36 b of the wedge-action holding (pinch) plate 36 is in flush contact with the tip section 35 a of the flat plate 35 .
[0046] As FIGS. 2, 11 and 12 show, the turning material 40 is attached so that it can freely turn with the aid of the axis 41 installed on the base plate 1 at the lower tip (base plate 1 side) of the flat plates 33 , 34 and 35 and the wedge-action holding (pinch) plate 36 , and is set to turn clockwise (in FIG. 2 ) via spring 42 .
[0047] As FIG. 12 shows, the tip 36 b of the wedge-action holding (pinch) plate 36 has a protrusion 36 c in the direction of the turning material 40 . Additionally, this latch protrusion 36 d is set in the horizontal direction from the tip of the protrusion section 36 c . As FIGS. 2 to 4 and FIG. 12 show, in a situation where the flat plate 35 and the tip of the wedge-action holding plat 36 are in close contact with each other, the protrusion 43 of the turning material 40 which is biased to arrow direction, is in contact with the latch protrusion 36 d of the wedge-action holding (pinch) plate 36 .
[0048] As shown in FIG. 12 , the released material 50 is arranged in a vertical direction, with freedom to slide along the base plate 1 between the turning material 40 and the base plate 1 . Additionally, its end-protrusion edge section 51 protrudes downward from the bottom side edge section 1 b in the horizontal direction of the upper corner section 1 a of the base plate 1 , while the other edge contact section 52 (see FIG. 3 ) is in contact with the bent section 36 a of the wedge-action holding (pinch) plate 36 .
[0049] Therefore, when in a state depicted in FIG. 12 the tip edge plate 23 a of the actuator arm 23 is used to insert the protrusion section 51 in the direction of the arrow shown in FIG. 11 . As shown in FIG. 5 , the contact section 52 of the other end of the release section material 50 will push and insert the bent section 36 a upward. Therefore, the wedge-action holding (pinch) plate 36 will resist the set force of the spring 38 and turn clockwise as shown in FIGS. 5 and 11 .
[0050] Accordingly, the protrusion 43 of the turn section material 40 is released from the latch protrusion 36 d , and the turn section material 40 will turn in the direction of the arrow ( FIG. 11 ) by the force set by the spring 42 , coming into contact with the protrusion edge section 51 . In this state the protrusion 43 is in contact with the rear side of the protrusion section 36 c of the wedge-action holding (pinch) plate 36 . Therefore, the actuator arm 23 becomes detached toward the lower side as shown in FIG. 6 , preventing the wedge-action holding (pinch) plate 36 from returning to its original position even if there is no push in the arrow direction as shown in FIG. 11 , maintaining a state whereby a gap remains with flat plate 35 .
[0051] As FIG. 7 shows, when the tip-protrusion section 44 of the turn section material 40 is pushed in with the tip edge plate 23 a of the actuator arm 23 in the state depicted in FIG. 11 , the wedge-action holding plate returns to its original position under the force set by the spring 38 , whereupon it becomes closed as shown in FIG. 12 because the protrusion 43 will proceed beyond (in FIG. 11 ) the protrusion section 36 c of the wedge-action holding (pinch) plate 36 and be released from the protrusion section 36 c.
[0052] As FIGS. 14 and 15 show, a foot section 61 and a base unit incorporating the foot section are installed at the rear of the base plate 1 parallel with the base plate 1 . On the rear surface of the base 60 , the work section material 63 is attached with axis 62 , allowing it to turn freely. A lever latch unit 64 located at one end of work section material 63 protrudes from the hole 65 in the base unit to the upper surface of the base unit 60 .
[0053] Additionally, a work bar 66 is fixed to the work section material 63 in a way that it protrudes from the hole 65 to the upper surface of the base unit 60 . The work section material 63 is set to turn counter-clockwise (in FIG. 14 ), centering on the axis 62 via the spring 67 .
[0054] As shown in FIGS. 16 and 17 , the operation lever 70 is fastened onto axis 71 so that it can turn freely in close proximity to the upper surface of the base unit 60 . (The work bar 66 is close against the upper surface of operating lever 70 .) The operating lever 70 is biased to move counter-clockwise (in FIG. 16 ) by the spring 72 (part of the spring being located on the rear side of the base unit 60 via the hole 61 a on the foot section 61 ).
[0055] A gear section 73 is set up along an arc on the upper part of the operation lever 70 and centering on axis 71 . Additionally, there is a notch 74 where the lever latch unit 64 of the work section material 63 can be fitted on the operation lever 70 .
[0056] A rotor 77 with a gear section 76 that fits with the aforementioned gear section 73 is attached so that it can freely turn on the axis 78 close to the upper surface of the base unit 60 . A protruding piece 79 is set vertically at one end of the rotor 77 . At the rear of the base plate 1 , a detector 80 is set so that the operation lever comes in contact with the detector when it is operated as shown in FIG. 21 .
[0057] As shown in FIG. 18 , a shutter 81 is attached to the base unit 60 so that it can freely turn on the same axis 78 close to the upper surface of the rotor 77 . The end section of the shutter 81 is in an arc shape 81 a so that it can create a circular space with the notch 31 of the base plate 1 when the shutter is closed as shown in FIG. 20 .
[0058] The shutter 81 is set by the spring 82 to turn clockwise (in FIG. 18 ), and pushes the work section material 66 in the clockwise direction while opposing the force of the spring 67 as the corner section 83 comes in contact with the bent tip section 66 a of the work bar 66 .
[0059] As shown in FIG. 19 , an arc-shaped plate 90 equipped with an approximately arc-shaped catch cavity 92 (see FIG. 21 ) is attached to the opposite side of the arc-shaped section 81 a of the shutter 81 so that it can freely turn on axis 91 . This arc-shaped plate 90 is biased to turn counter-clockwise (in FIG. 19 ) around the axis 91 via the force of the spring 93 .
[0060] Additionally, on the upper surface of the shutter 81 is attached a disk that can turn freely around the axis 78 . The disk 100 has a tongue 101 extending in the direction of the radius. Additionally, a notch 101 a that couples with protrusion piece 79 of the rotor 77 is located on one side of the tongue 101 .
[0061] Additionally, on another location of the disk 100 in the direction of the circumference is an extension, being an ear-like protrusion 102 set in the direction of the radius and designed to fit with the catch cavity 92 of the aforementioned arc-shaped plate 90 . Additionally, there is a protrusion 102 a protruding vertically from the ear-shaped piece 102 . Through the spring 103 , the protrusion 79 of the toe rotor 77 and the protrusion 102 a are biased to move away in the direction of the circumference.
[0062] As shown in FIG. 19 , when the shutter 81 is opened, the ear-shaped piece 102 of the disk 100 engages the catch cavity 92 because the arc-shaped plate 90 receives the force from the spring 93 to turn counter-clockwise.
[0063] When one holds the handle 1 d of the base plate 1 under the situation shown in FIG. 19 and turns the lower end section of the operation lever 70 clockwise in opposition to the force of the spring 72 , the rotor 77 turns counter-clockwise (in FIG. 19 ) with the gears 73 and 76 engaged. This turn force is applied via the spring 103 to the protrusion 102 a of the ear-shaped piece 102 of the disk 100 , and the force is applied to the arc-shaped plate 90 that is hooked to the ear-shaped piece 102 .
[0064] The force applied to this arc-shaped plate 90 also acts on the axis 91 . Therefore, the shutter 81 turns counter-clockwise on the axis 78 while opposing the force of the spring 82 (simultaneously the rotor 77 , disk 100 and arc-shaped plate 90 also turn in an integrated fashion), ending in the state shown in FIG. 20 . In the state depicted in FIG. 19 , the operation lever 70 will be unable to turn as shown in FIG. 20 because the lever latch part 64 of the lower edge of the work section material 63 engages notch 74 of the operation lever 70 due to the force applied by the spring 67 . If the operation lever 70 is unable to turn, the rotor 77 with its gear meshed with that of the lever is also unable to turn.
[0065] Even if the user's finger is released from the operation lever 70 , the shutter 81 in FIG. 20 remains closed because the ear-shaped piece 102 engages the catch cavity 92 and the rotor 77 , and because disk 100 and arc-shaped plate 90 are in a state of integration.
[0066] As shown in FIGS. 3, 4 , 6 , 13 and 20 , the pivot pin 111 is set to turn freely on the base plate 1 around the axis 110 . As FIG. 13 shows, the pivot pin 111 is divided into sections 111 a and 111 b , with the tip bent vertically with the bent sections designated as 111 a ′ and 111 b ′.
[0067] In the FIG. 20 state where the shutter 81 remains closed, bent section 111 b ′ of the pivot pin 111 is located close to the tip section 94 of the arc-shaped plate 90 . Accordingly, and as explained later, the actuator arm 23 turns counter-clockwise (in FIG. 6 ) once the tape is severed. As shown in FIG. 6 , when the pivot pin 111 is pressed, the pin turns around the axis 110 and the bent section 111 b ′ applies pressure to the tip section 94 of the arc-shaped plate 90 .
[0068] The arc-shaped plate 90 then turns clockwise (in FIG. 20 ) around the axis 91 in opposition to the force of the spring 93 . Accordingly, the ear-shaped piece 102 of the disk 100 is released from the catch cavity 92 of the arc-shaped plate 90 , as shown in FIG. 21 .
[0069] The rotor 77 , whose gears are engaged with those of the operation lever 70 , is unable to rotate. Moreover, while the disk 100 engaged with protrusion piece 79 of the rotor 77 it is unable to turn because of the spring 103 , the shutter 81 and the arc-shaped plate 90 —as attached to shutter 81 —turn clockwise as shown in FIG. 21 by the force of the spring 82 . The tip of the ear-shaped piece 102 will be in a state of being pressed against the edge surface 90 a of the arc-shaped plate 90 by the force of the spring 93 .
[0070] When the shutter 81 opens, the lever latch unit 64 is released from the notch 74 of the operation lever 70 as the corner section 83 pushes the bent tip section 66 of the work bar unit 66 to the left and then returns to the state shown in FIG. 19 as the operation lever 70 turns counter-clockwise around axis 71 by the force of the spring 72 .
[0071] Simultaneously, with the counter-clockwise turning of the operation level 70 , the rotor 77 ( FIG. 16 ), with its gears engaged with the operation lever 70 , rotates in the clockwise direction, and the protrusion 79 of the rotor 77 applies pressure on the tongue piece 101 of the disk 100 , causing the disk 100 to turn clockwise. The ear-shaped piece 102 of the disk 100 slides along the edge surface 90 a of the arc-shaped plate 90 from the state depicted in FIG. 21 and returns to the state depicted FIG. 19 once it is clamped into the catch cavity 92 of the arc-shaped plate 90 .
[0072] As shown in FIGS. 1 and 13 , a band-shaped gate 120 on the inner, upper end of the cover plate 2 is attached to turn freely on the axis 121 , and is set by the spring 122 to close the entrance. Detector 123 , which detects turning movements in the direction that pushes inward, is located inside the gate 120 .
[0073] The following explanation will cover the movements of the binding apparatus. As indicated in FIG. 22 , for example, if the free end of the adhesive tape A (A 1 being the adhesive side) made of paper is held at both ends (to be explained later) from the tip of the wedge-action holding (pinch) plate 36 and the flat plate 35 , the user will hold the handle section 1 d with his hand and place the object B to be bound within the notch 31 by turning the gate 120 inward after pressing the gate 120 against the object B to be bound in a state where the actuator arm 23 and the guide arm 28 are standing by in the position shown in FIG. 2 . The shutter 81 will close as shown in FIGS. 3 and 20 , just as explained previously, if the user pulls the trigger of the operation lever 70 with his finger in order to turn the lever.
[0074] The turning of the gate 120 is detected by detector 123 , while the closing of the shutter 81 by operation lever 70 is detected by detector 80 and the respective detection signals are output to the control circuit 130 . The control circuit 130 activates the motors 12 and 20 by sending the drive-control signals to the motors. The plate 10 moves horizontally with the drive of the motor 12 , which also drives the gear 22 to turn. The amount of movement of plate 10 is sensed by the detector 131 , while the degree to which the gear 22 turns is detected by the detector 132 and the results are sent to the control circuit 130 .
[0075] The control circuit 130 sends the drive-control signals to the motors 12 and 20 in accordance with these two detected signals, and then activates the motors as follows: First, the plate 10 is moved from the standby state of FIG. 2 to the right side, while the tips of the actuator arm 23 and guide arm 28 are turned counter-clockwise to go underneath the object B to be bound, as shown in FIG. 3 . Next, the arm tips are turned clockwise as shown in FIG. 4 to surround object B to be bound with the adhesive tape A stretched taut. Additionally, Tapes A′ and A″ (shown in FIG. 4 ) are bonded together as shown in FIG. 5 . Thereafter, the cutting plate 25 at the tip of the actuator arm 23 is inserted between flat boards 33 and 34 to sever the tape A.
[0076] When the tape is cut, the wedge-action holding (pinch) plate 36 ( FIG. 8 ), as explained previously, will detach itself from the flat plate 35 as shown in FIG. 11 and the free end of tape A will be released.
[0077] Once the tape is cut, the actuator arm 23 and the guide arm 28 turn counter-clockwise as shown in FIG. 6 to apply pressure on the pivot pin 111 . Therefore, the shutter 81 opens, as explained previously, and the operation lever 70 returns to its position. When the user moves the binding apparatus to the right side (in FIG. 6 ) as if to push out the object B that is bound by the tape A, the gate 120 returns to its position due to the action of the spring 122 .
[0078] When the shutter 81 opens, detected signals are output to the control circuit 130 from the detector 81 . Additionally, when the gate 120 returns to its position, the detector 123 sends the detected signals to the control circuit 130 . Accordingly, the control circuit 130 outputs drive-control signals to motors 12 and 20 . Therefore, the actuator arm 23 and guide arm 28 turn clockwise as shown in FIG. 7 . As shown in FIGS. 7 and 9 , the insert plate 24 inserts the end section of the severed tape A between the flat plate 35 and the wedge-action holding (pinch) plate 36 . Simultaneously the wedge-action holding (pinch) plate 36 (described previously) returns to its position and, as shown in FIG. 10 , holds the end section of the inserted tape A together with the flat plate 35 .
[0079] Next, the actuator arm 23 and guide arm 28 return to a standby position of FIG. 2 . Therefore, the end section of tape A moves to the state shown in FIG. 22 from the state shown in FIG. 10 .
[0080] In this manner the embodiment of the binding apparatus holds onto the free end of adhesive tape A and wraps the tape around the object B to be bound by moving the tip of the guide arm 28 for guiding the tape A around the periphery of the object B to be bound with the tape A stretched taut, and then binds the tape together. After this, the end section of the tape is severed and the end of the tape A is held. Because the object B to be bound is wrapped in non-adhesive tape A by wrapping the tape around the object B with the tape stretched taut, the object B can be firmly bond with this simple operation.
[0081] This disclosure provides exemplary embodiments of the present invention. The scope of the present invention is not limited by these exemplary embodiments. Numerous variations, whether explicitly provided for by the specification or implied by the specification, such as variations in structure, dimension, type of material and manufacturing process may be implemented by one of skill in the art in view of this disclosure.
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A binding apparatus for binding both ends of an adhesive tape around an object has a base plate. A tape-retaining member is coupled to the base plate and has a spool onto which the adhesive tape is wound, allowing the spool to turn freely. An opening is located at one end of the base plate that houses the object to be wound. A tape-end processing device holds the adhesive tape from both ends and releases the free end of the adhesive tape. A plate is provided that freely moves in a direct line from the opening in the base plate to the tape-retaining section, and an arm coupled on the plate so that rotates freely. A plate-transfer device is provided for moving the plate in a straight-line direction. An arm-turning device is coupled to the arm to turn the arm. A straight-line position-detection device is provided that detects the position of the plate. A turn position-detection device detects the turning position of the arm. A control device controls the drive of the plate-transfer device and the arm-turning device with signals detected by the straight line position-detection device and the turn position-detection device.
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GOVERNMENT FUNDING
This invention was made, in part, with support by grants from the United States Department of Agriculture (95-37308-1843), the United States Department of Agriculture Cooperative Research Agreement (3620-41000-051-02S), the United States Department of Energy (DE-FG05-86ER13574) and the University of Florida. The government may have certain rights in the application.
BACKGROUND OF THE INVENTION
Ultrasound can be defined as sound waves above the range of human perception (Price, 1992). Currently, many ultrasonic technologies such as SONAR, medical diagnostics, and surface cleaners are available. SONAR and medical applications typically use low power and high frequency (≧1 MHz). Surface cleaning applications, however, depend on ultrasonic cavitations created by lower frequency (20-50 Khz) and high power ultrasound.
Ultrasonic cavitations result from the rapid compression and expansion of a liquid. In the expansion phase, the liquid is “torn apart”, resulting in the formation of voids or bubbles (Price, 1992; Leeman and Vaughan, 1992). These bubbles gradually increase in size until a critical size is reached, where critical size (usually 100-200 μm in diameter) is dependent on the frequency of the oscillation and the presence of any nucleating agents, e.g., dissolved gasses, cracks and crevices on a solid surface, or suspended solids (Atchley and Crum, 1988; Price, 1992). Once its critical size is reached, the bubble implodes, at times, generating temperatures approaching 5,500° C. within the bubble (Suslick, 1989, Price, 1992). When collapse of a cavity occurs in a solution free of solid particles, heating is the only consequence. However, if implosion occurs near a solid surface, implosion is asymmetric. As water rushes to fill the void left by the imploding bubble (e.g., at speeds near 400 m/s) shock pressures of 1-5 Kpa can be generated (Suslick, 1988; Suslick, 1989; Price, 1992).
The physical effects of ultrasonic cavitations have been known since the early testing of the first British destroyer, the H.M.S. Daring, in 1894 (Suslick, 1990). The rapid revolution of a ship propeller creates the same, high frequency, compressions and expansions created by ultrasound (Suslick, 1989). Cavitations around the Daring's propeller caused pitting of the metals used. This effect of cavitations on metal surfaces has been confirmed in studies on ultrasonic cavitations (Leeman and Vaughan, 1992; Boudjouk, 1988). High intensity stirring, the dispersal of suspended solids, increased diffusion through cellulose gels, and emulsification of immiscible liquids are other effects attributable to ultrasonic cavitations (Ensminger, 1973).
The high temperatures, pressures and velocities produced by ultrasonic cavitation can also create unusual chemical environments (Suslick, 1989). Compounds in aqueous solution have been shown to form free radicals when subjected to ultrasound. Water, when subjected to ultrasound, creates H. and .OH intermediates, ultimately producing H 2 and H 2 O 2 (Suslick, 1988). Other chemical effects can be caused by high velocity collisions driven by shock waves. The agglomeration of metallic particles in ultrasonic fields has been shown (Suslick, 1989; Suslick, 1990).
Ultrasonic surface cleaners have been available for use since the early 1950's (Shoh, 1988). The mechanism of the cleaning action is reliant on the formation of cavitation bubbles. The contaminant coat can be gradually eroded through cavitational action. Alternatively, the formation of cavitational bubbles between the coat and the surface, effectively peels the coat away from the surface. Other designs of ultrasonic cleaning systems have extremely high efficiency (>95%).
Most biological applications of ultrasonic technology have been directed towards the disruption of cell membranes (Shoh, 1988; Ausubel, 1996). One such device is Fisher Scientific's Model 550 Sonic Dismembrator. Recently, the effects of lower intensities of ultrasound on bacteria have been investigated. It has been shown that nonlethal doses of ultrasound may cause the induction of the SOS response and the transcription of heat shock proteins in Escherichia coli (Volmer et al., 1996). Some of the physical damage to E. coli, by ultrasonic cavitation, has been illustrated recently (Allison et al., 1996), showing the disruption of the plasma membrane and subsequent leakage of intracellular components.
In the fermentation of milk by Lactobacillus bulgaricus, the rate of lactose hydrolysis was increased with the use of discontinuous ultrasound (Wang et al., 1996). Presumably, the cause of the increased rate of hydrolysis was the release of intracellular enzymes into the media. After ultrasonic treatment was stopped, L. bulgaricus was able to recover and grow.
Recent interest in ultrasound has been shown by those involved in research in the paper industry investigating its uses as a de-inking device in the recycling of various office paper (Scott and Gerber, 1995; Sell et al., 1995; Norman et al., 1994). It was reported that, because of ultrasonic treatment, the structure of the paper was changed such that its water holding capacity increased.
Besides the recycling of paper products, there is an interest in the fermentation of waste paper and other lignocellulosic products into ethanol. The production of ethanol from such products reduces environmental waste problems and reduces reliance on petroleum-based automotive fuels. (Hohmann and Rendleman, 1993; Sheehan, 1993). Accessibility of the substrate to cellulase is a primary factor influencing the efficiency of enzymatic degradation of cellulose (Nazhad et al., 1995).
Cellulase from T. longibrachiatum is known to bind to cellulose tightly (Brooks and Ingram, 1995). The binding has also been shown to be dependent on the intensity of agitation (Kaya et al., 1994). Similar effects were seen with an intensive mass transfer reactor, where extremely high rates of hydrolysis were achieved (Gusakov et al., 1996).
SUMMARY OF THE INVENTION
Improved methods for enzymatically converting lignocellulose, for example, to ethanol, are desirable. This invention reports the use of ultrasonic treatment in a Simultaneous Saccharification and Fermentation (SSF) process to enhance the ability of cellulase to hydrolyze mixed office waste paper (MOWP), thereby reducing cellulase requirements by ⅓ to ½. SSF is a process wherein ethanologenic organisms, such as genetically engineered micro-organisms, such as Escherichia coli KO11 (Ingram et al., 1991) and Klebsiella oxytoca P2 (Ingram et al., 1995), are combined with cellulase enzymes and lignocellulose to produce ethanol. Enzyme cost is a major problem for all SSF processes.
In conducting the invention, enzyme stability is not affected and, surprisingly, continuous ultrasonic treatment results in a decrease in hydrolysis relative to discontinuous treatment. One possible explanation is that the resultant mixing does not allow the cellulase to rebind cellulose long enough for catalysis to occur. Therefore, time to allow catalysis between ultrasonic treatments is desired.
The SSF of waste office paper by K. oxytoca may also be “cycle dependent.” Considering the inhibitory effect of ultrasound on the growth of K. oxytoca P2, a “recovery period” appears to be desired. With variation in the treatment schedule, such as increasing or decreasing treatment time throughout the course of fermentation, further optimization of the fermentation can be possible.
The use of ultrasound in the conversion of cellulose to ethanol represents a significant improvement in the SSF process. This is particularly true where lignin residues were used to generate the electricity required for the process. Ultrasound can be delivered in other manners as well, with liquid whistle systems, which are able to increase the water holding capacity of recycled paper (Scott and Gerber, 1995). Such a device in a piping loop can produce the desired disruption of the fine structure of cellulose, with a lower energy input.
In one embodiment, the invention comprises a method for the enzymatic degradation of lignocellulose, such as in the production of ethanol from lignocellulosic material, comprising subjecting the material to ultrasound, as in a continuously-operating ultrasonic device, cellulase enzymes, optionally an ethanologenic yeast or an ethanologenic bacterium and/or a fermentable sugar, and maintaining the mixture thus formed under conditions suitable for the production of ethanol. In an alternative embodiment, the ultrasonic device is operated discontinuously.
In a preferred embodiment, the ethanologenic organisms are organisms (particularly recombinant bacteria or yeast) which express one or more enzymes or enzyme systems which, in turn, catalyze (individually or in concert) the conversion of a sugar (e.g., xylose and/or glucose) to ethanol. Preferred ethanologenic organisms include species of Zymomonas, Erwinia, Klebsiella, Xanthomonas and Escherichia. In a highly preferred embodiment, the bacterium is K. oxytoca P2.
In another embodiment the ethanologenic yeast or ethanologenic bacterium contains enzymes that degrade lignocellulosic material, wherein the enzymes are released from the ethanologenic micro-organism by ultrasonic disruption.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows that ultrasonic treatment did not affect the activity of the added cellulase or β-glucosidase.
FIGS. 2A and 2B show the susceptibility of K. oxytoca P2 to ultrasonic damage.
DETAILED DESCRIPTION OF THE INVENTION
As described above, the invention relates to an improved method for the enzymatic hydrolysis of lignocellulose comprising subjecting an aqueous mixture containing lignocellulose with ultrasound; and contacting the mixture with a cellulase under conditions sufficient for hydrolysis. The aqueous mixture can be subjected to the ultrasound treatment continuously or discontinuously. Typically, the ultrasound will be conducted with commercially available equipment. Examples of suitable ultrasonic probes include the RS-20 Ultrasonic Tubular Resonator and the RG-36/RS-36 Tube Resonator Systems (Telsonic USA, Bridgeport, N.J.). These ultrasonic probes may be combined with ultrasonic generators to maintain desired operating parameters, such as operating frequency and power. Examples of suitable ultrasonic generators include the RG-20 Ultrasonic-Generator and the MRG-36-150 Module-Cleaning-Generator (Telsonic USA, Bridgeport, N.J.). The ultrasound treatment may be conducted at a wide-range of frequencies, all of which exhibit similar effects. For example, the frequency can be between above 2 and 200 kHz. The duration and conditions of the ultrasonic step is selected to avoid overheating of the mixture to a temperature at which significant amounts of the enzyme(s) will be denatured. Generally, the duration of the ultrasound treatment lasts between 10 minutes and 30 minutes. Without being limited in anyway by theory, the ultrasound treatment is typically sufficient to disrupt the crystalline structure of the lignocellulosic material.
The term “continuous” treatment is defined herein to include a single treatment with ultrasound for the duration of the enzymatic hydrolysis, i.e. there are no intermediary periods between or during enzymatic hydrolysis in which there is no ultrasound. The term “discontinuous” treatment is defined herein to include multiple treatments with ultrasound between or during enzymatic hydrolysis. In yet another embodiment, the ultrasonic treatment can be a single exposure to ultrasound prior to enzymatic hydrolysis.
The lignocellulose material can be obtained from lignocellulosic waste products, such as plant residues and waste paper. Examples of suitable plant residues include stems, leaves, hulls, husks, cobs and the like, as well as wood, wood chips, wood pulp, and sawdust. Examples of paper waste include discard photocopy paper, computer printer paper, notebook paper, notepad paper, typewriter paper, and the like, as well as newspapers, magazines, cardboard, and paper-based packaging materials.
The aqueous mixture containing lignocellulose subjected to the ultrasonic treatment can further comprise a cellulase enzyme for the enzymatic hydrolysis. In yet another embodiment, the cellulase enzyme is added subsequent to the ultrasound treatment. The cellulase can be provided as a purified enzyme or can be provided by a cellulase-producing microorganism in said aqueous mixture. Cellulases, as that term is used herein, includes any enzyme that effects the hydrolysis or otherwise solubilizes cellulase (including insoluble cellulose and soluble products of cellulose). Cellulase enzymes, including purified enzyme preparations, organisms expressing the same, are known in the art. Suitable sources of cellulase include such commercial cellulase products as Spezyme™ CP, Cytolase™ M104, and Multifect™ CL (Genencor, South San Francisco, Calif.), and such organisms expressing cellulase as the recombinant bacterium of U.S. Pat. No. 5,424,202, which is incorporated herein by reference.
The conditions for cellulase hydrolysis are typically selected in consideration of the conditions suitable for the specific cellulase source, e.g, bacterial or fungal. For example, cellulase from fungal sources typically works best at temperatures between about 30° C. and 48° C. and a pH between about 4.0 and 6.0. In general, typical conditions include a temperature between about 30° C. and 60° C. and a pH between about 4.0 and 8.0.
The aqueous mixture can further advantageously comprise an ethanologenic microorganism which has the ability to convert a sugar or oligosaccharide to ethanol. Ethanologenic microorganisms are known in the art and include ethanologenic bacteria and yeast. The microorganisms are ethanologenic by virtue of their ability to express one or more enzymes which, individually or together, convert a sugar to ethanol. It is well known, for example, that Saccharomyces (such as S. cerevisiae ) are employed in the conversion of glucose to ethanol. Other microorganisms that convert sugars to ethanol include species of Schizosaccharomyces (such as S. pombe ), Zymomonas (including Z. mobilis ), Pichia ( P. stipitis ), Candida ( C. shehatae ) and Pachysolen ( P. tannophilus ).
Preferred examples of ethanologenic microorganisms include ethanologenic microorganisms expressing alcohol dehydrogenase and pyruvate decarboxylase, such as can be obtained with or from Zymomonas mobilis (see U.S. Pat. Nos. 5,000,000; 5,028,539; 5,424,202; and 5,482,846, all of which are incorporated herein by reference).
In another embodiment, the ethanologenic microorganism can express xylose reductase and xylitol dehydrogenase, which convert xylose to xylulose. Xylose isomerase converts xylose to xylulose, as well. The ethanologenic microorganism can further express xylulokinase, which catalyzes the conversion of xylulose to xylulose-5-phosphate. Additional enzymes to complete the pathway can include transaldolase and transketolase. These enzymes can be obtained or derived from Escherichia coli, Klebsiella oxytoca and Erwinia species. For example, see U.S. Pat. No. 5,514,583.
It is particularly preferred to employ a microorganism which is capable of fermenting both pentoses and hexoses to ethanol, such as are obtained from preparing a recombinant organism which inherently possesses one set of enzymes and which is genetically engineered to contain a complementing set of enzymes. Examples of such microorganisms include those described in U.S. Pat. Nos. 5,000,000; 5,028,539; 5,424,202; 5,482,846; 5,514,583; and Ho et al., WO 95/13362, all of which are incorporated herein by reference. Particularly preferred microorganisms include Klebsiella oxytoca P2 and Escherichia coli KO11.
The conditions for converting sugars to ethanol are typically those described in the above referenced U.S. Patents. Generally, the temperature is between about 30° C. and 40° C. and the pH is between about 5.0 and 7.0.
It is generally advantageous to add nutrients and/or cofactors for the microorganisms and/or enzymes to optimize the enzymatic conversions. For example, xylose reductase employs NADPH and xylitol dehydrogenase employs NAD as cofactors for their respective enzymatic actions. In contrast, bacterial xylose isomerase requires no co-factor for direct conversion of xylose to xylulose. It is also desirable to add, or subject the microorganism separately to, assimilable carbon, nitrogen and sulfur sources to promote growth. Many mediums in which to grow microorganisms are well known in the art, particularly Luria broth (LB) (Luria and Delbruk, 1943).
Where the ultrasound treatment is conducted in the presence of a microorganism, the ultrasound can be conducted at a frequency and duration such that a portion of all the microorganisms present are lysed or otherwise subjected to membrane disruption. Such a method can result in a controlled release of the enzymes from the microorganisms into the surrounding medium, thereby allowing the optimization of enzymes either alone or in conjunction with commercial enzymes and reduce the overall cost of commercial enzymes.
Examples of microorganisms containing desirable enzymes include those described in U.S. Pat. No. 5,424,202 to Ingram, et al. Other microorganisms are disclosed in U.S. Pat. No. 5,028,539 to Ingram et al., U.S. Pat. No. 5,000,000 to Ingram et al., U.S. Pat. No. 5,487,989 to Fowler et al., U.S. Pat. No. 5,482,846 to Ingram et al., U.S. Pat. No. 5,554,520 to Fowler et al., U.S. Pat. No. 5,514,583 to Picataggio, et al., copending applications having U.S. Ser. No. 08/363,868 filed on Dec. 27, 1994, U.S. Ser. No. 08/475,925 filed on Jun. 7, 1995 and U.S. Ser. No. 08/218,914 filed on Mar. 28, 1994 and standard texts such as, Ausubel et al., Current Protocols in Molecular Biology, Wiley-Interscience, New York (1988) (hereinafter “Ausubel et al.”), Sambrook et al., Molecular Cloning: A Laboratory Manual, Second and Third Edition, Cold Spring Harbor Laboratory Press (1989 and 1992) (hereinafter “Sambrook et al.”) and Bergey's Manual of Systematic Bacteriology, William & Wilkins Co., Baltimore (1984) (hereinafter “Bergey's Manual”) the teachings of all of which are hereby incorporated by reference in their entirety. Yet other embodiments include those described in U.S. Ser. No. 08/834,901, filed concurrently herewith by Ingram et al. and U.S. Ser. No. 08/879,005 by Ingram et al. which are incorporated herein by reference.
An example of a suitable device to deliver the ultrasound is Fisher Scientific's Model 550 Sonic Dismembrator, Telsonic Ultrasonic Tubular Resonator RS-20, Telsonic Ultrasonic-Generator RG-20, or Telsonic Tube Resonator System Series RG-36/RS-36. In one embodiment, an ultrasonic immersion horn can be used directly in the aqueous medium. Alternatively, the ultrasound can be emitted into a liquid filled vat in contact with a vat containing the aqueous medium (such as a first vat placed within a second vat, either of which can contain the aqueous medium). It may also be desirable, in a continuous system to flow the aqueous medium through a container, or vat, with the ultrasonic device which, continuously or discontinuously, emits ultrasound. In yet another embodiment, it can be desirable to control the temperature of the aqueous medium by surrounding the container, or vat, with cooling water, or other suitable heat exchange arrangement. It is within the ability of one of ordinary skill in the art to determine how to optimize the release of enzymes from microorganisms, said enzymes to be used alone or in conjunction with commercial enzymes, to achieve optimum ethanol production.
Methods and Materials
The methods and materials described below were used in carrying out the work described in the examples which follow. For convenience and ease of understanding, the methods and materials section is divided into sub-headings as follows.
Organism and Media
All fermentations of Mixed Waste Office Paper (MWOP) used K. oxytoca P2 as the biocatalyst. Luria broth (LB) (Luria and Delbruk, 1943) was used as the source of nutrients for all liquid and solid media. Solid media also contained 15 g/L agar and 20 g/L glucose. For the propagation of inoculum, liquid media containing 50 g/L glucose was used. Chloramphenicol (40 mg/L) was used as required for selection. Cultures were maintained on agar plates containing either 40 mg/L Cm or 600 mg/L Cm. The commercial cellulase Spezyme™ CP (Genencor, South San Francisco, Calif.), a mixture of cellulase enzymes from Trichoderma longibrachiatum (formerly T. reesei ), was used. Novozyme 188, β-glucosidase from Aspergillus niger (Novo-Nordsk, Franklintin N.C.) was also used in saccharification experiments.
Enzyme Activity and Sugar Analysis
Endoglucanase activity was determined as previously described (Wood and Bhat, 1988). Cellulase mixtures were diluted in 50 mM citrate buffer, pH 5.2, containing 2% CMC and incubated at 35° C. Release of reducing sugars was determined by the DNS method as described (Chaplin, 1987). Cellobiase activities were determined by measuring the rate of p-nitrophenol (p-NP) release (Abs. 410 nm ) from p-nitrophenyl-β-D-glucoside (p-NPG) at pH 5.2, 35° C. (Wood and Bhat, 1988). Enzyme solutions were diluted in 50 mM citrate buffer, pH 5.2, as required. One ml of diluted enzyme was added to 1 ml 2 mM p-NPG and incubated at 35° C. Reactions were terminated with the addition of 1 M Na 2 CO 3 .
Enhancement of Sugar Release from MWOP
125 g dry wt. shredded MWOP was added with 25 ml 18 N H 2 SO 4 and 2 L H 2 O in a 3-liter stainless steel beaker. The slurry was allowed to react fully with the carbonate present in the paper (monitored by gas evolution). The pH was then adjusted to approximately 2.5 and autoclaved (121° C.) for 20 minutes. After overnight cooling, 125 ml 1 M sodium citrate was added and the volume was brought to 2.5 L with H 2 O. The pH was adjusted to 5.2 and was placed in a constant temperature bath, 35° C. Mixing was done with a 750-mm Rushton-type radial flow impeller and a Ciambanco model BDC-1850 laboratory mixer. Five FPU Spezyme™ CP per gram of paper (625 FPU/2.5 L) and 50 U Novozyme 188 per liter (250 U/ 2.5 L) were also added. Units used were as reported by the manufacturer. Thymol, 0.5 g/L, and chloramphenicol, 40 mg/L was added to prevent microbial growth. Ultrasound was produced by a Telsonic 36 KHz Tube Resonator (>95% efficiency), model RS-36-30-1 with an accompanying model MRG-36-150 (150 W effective output) ultrasonic generator (Telsonic USA, Bridgeport, N.J.). The frequency was tuned automatically. Treatment cycles were controlled by an SPER Scientific 810030 timer (Fisher Scientific Co., St. Louis, Mo.). Mixing speeds were constantly adjusted to the lowest setting that would allow mixing (600-75 rpm).
Enzyme Stability
The enzyme preparations were diluted in 50 mM citrate buffer to concentrations equivalent to those used in the study of sugar release from MWOP, 250 FPU Spezyme™ CP/L and 50 U/L Novozyme 188. Solutions also contained 0.5 g/L thymol and 40 mg/L Cm to prevent microbial growth. The enzyme mixture was stirred (120 RPM) for 15 minutes to ensure complete dispersal of the enzyme. Stirring was continued for 48 hours with or without continuous exposure to ultrasound. Samples were taken at 0, 12, 24, 36, and 48 hours. Enzyme activities were assayed as described above.
Cell Viability
To 1.75 L of LB containing 50 g/L glucose and 40 mg/L Cm, K. oxytoca P2 was used to inoculate to an initial cell density, measured as O.D. 550 nm , of 0.5. Growth was allowed to proceed for 12 hours with or without ultrasonic treatment. Samples were taken and dilutions were made to follow cell growth at 0, ¼, ½, 1, 2, 4, 8, and 12 hours. Optical density (O.D. 550 nm ) and pH were measured on each sample. Dilutions were spread on agar plates (20 g/l glucose) and incubated overnight (30° C.). Colony forming units (CFUs) were mounted as a measurement of cell viability.
Ultrastructural Effects
The change in the structure of the cellulose matrix of MWOP was investigated using a Hitachi S4000 scanning electron microscope. Samples were prepared by subjecting 2.5 L mixtures of 50 g/L MWOP in 50 mM citrate buffer, pH 5.2 and 35° C., to one hour of continuous ultrasound. Other samples were treated with cellulase for 4 hours. Control samples were taken before any treatment. All samples were dried and sputter coated with gold before being examined (Doran et al., 1994).
Cell Propagation
K. oxytoca P2 was transferred from a stock culture (−20° C.) to agar plates with 20 g/L glucose and Cm (40 mg/l and 600 mg/l). An isolated colony was then transferred daily from the plate with 600 mg/L Cm to fresh plates containing both concentrations of Cm. Isolated colonies from plates with 40 mg/L Cm were used to inoculate flasks with LB and 50 g/L glucose. Inoculated flasks were incubated overnight at 30° C. after which they were harvested by centrifugation for further use.
SSF with Ultrasonic Treatment
Fermentations of MWOP were conducted in 14 L glass fermentation vessels (10 L working volume) using Multiferm™ fermentors models 100 and 200 (New Brunswick Sci. Co., N.J.). Stainless steel head plates were modified by removing components that extended into the broth. Head plates were sanitized with 10 g/L formaldehyde by coating all surfaces with the formaldehyde while loosely enclosed in a large plastic autoclave bag. One kg, dry weight, shredded MWOP was placed in fermentation vessels with 8 L H 2 O and 110 ml 18 N H 2 SO 4 . The mixture was autoclaved for one hour. After cooling, the slurry was further homogenized by vigorous mixing with a hand drill and a paint mixing attachment. After autoclaving for an additional one hour and subsequent cooling, 5 FPU Spezyme™ Cp/g MWOP, 1 L 10×LB (pH 5.0) and H 2 O was added to a final volume of 10 L. This solution was partially mixed by hand, using a sterilized industrial baking whisk, to disperse the enzymes and nutrients. Cells were added to an initial O.D. 550 nm of 0.5. Ultrasonic treatments were as described above. Because of its nonhomogeneous nature, no samples were taken for an initial ethanol determination. Samples were taken at 24, 48, 72, and 96 hours.
EXAMPLE 1
Analysis of Enhanced Rates of Sugar Release
Using the methods and materials outlined above for “Enhancement of Sugar Release from MWOP,” it was found that with the use of ultrasonic energy the rate of enzymatic hydrolysis was increased up to 40%. When sugar release with ultrasonic treatment 15 minutes every four hours is compared with treatment every two hours,a strong correlation between the amount of ultrasonic energy and sugar release is found. The increased rate of sugar release is due to a stimulation of enzymatic activity, not a physical or chemical hydrolysis by reactive byproducts from the sonolysis of water, as illustrated by the experiments without enzymes added. Interestingly, with continuous ultrasonic treatment, the rate of the hydrolysis goes down. Results are set forth in table format in Table 1.
TABLE 1
Effects of ultrasonic cavitation on enzymatic hydrolysis of mixed waste
office paper.
Number
Ener-
of
gy
Glucose equivalents b,c
Ultrasonic
Experi-
input
(mM)
treatment a
ments
(W)
@ 24 h
36 h
48 h
No ultrasound
3
0
88.1 ± 6.1
98.3 ± 6.1
106.9 ± 7.8
15 min. Per 4 h
3
9.37
96.5 ± 6.4
113.6 ±
128.3 ± 8.4
8.0
15 min. Per 2 h
3
18.75
115.5 ±
133.2 ±
149.0 ± 11.0
14.3
10.6
Continuous
3
150
98.1 ± 2.5
112.5 ±
126.6 ± 2.1
5.5
Continuous (no
2
150
0.67
0.67
0.58
enzyme)
a Ultrasonic treatments were automatically controlled to turn on and off at stated intervals.
b Experiments contained 5 FPU Spezyme ™CP and 10 IU Novozyme 188 /g MWOP.
c Based on analysis of reducing termini and assuming all are monomeric.
EXAMPLE 2
Enzyme Stability
Using the methods and materials outlined above for “Enzyme Stability,” it was found that ultrasonic treatment did not affect the stability of the added cellulase or β-glucosidase, as depicted in FIG. 1 . Both activities remained quite stable even with continuous exposure to ultrasound. The apparent increase in β-glucosidase may be due to the dispersal of protein aggregates in the highly concentrated, commercial, enzyme preparation.
EXAMPLE 3
Cell Viability
Using the methods and materials outlined above for “Cell Viability,” it was found that ultrasonic treatment appeared to be nonlethal, but was inhibitory to growth, as shown in FIGS. 2A and 2B. This observation may be due in part to an induction of an SOS response by the cells. This was further supported by the observations of pH, which slightly increased (pH 6.9 from an initial pH 6.7). Additionally, it was observed that the relative turbidity of the broth had little change throughout the exposure to ultrasound. Meanwhile, without ultrasonic treatment, a classical growth curve was observed.
EXAMPLE 4
Effects on SSF
Using the methods and materials outlined above for “SSF with Ultrasonic Treatment,” the combination of K. oxytoca P2 with ultrasonic treatment resulted in as much as a 15% increase in ethanol yields. Ethanol production from waste office paper treated with ultrasound and K. oxytoca P2 is summarized in Table 2. As might be expected from the inhibition of cell growth, increased ultrasonic treatment results in reduced ethanol production. Treatment every two hours may not be significantly different from treatment every four hours, however, a statistically significant difference between ultrasonic treatment every four hours and no treatment was found.
TABLE 2
Effects of ultrasonic treatment on ethanol production in SSF of MWOP
using K. oxytoca P2 as the biocatalyst
[Enzyme] a
[Ethanol]
Yield b,c
Ultrasonic
(FPU/g
(g/L)
(GE/g
treatment
Replicates
MWOP)
24 h
48 h
72 h
96 h
Cellulose)
None
2
10
15.7
27.3
33.5
35.3
0.39
None
4
5
9.5 ± 2.3
19.0 ± 2.7
25.7 ± 2.5
29.4 ± 2.9
0.33
15 min. Per 4 h
5
5
14.3 ± 2.0
26.1 ± 1.3
31.3 ± 1.3
34.0 ± 1.9
0.38
(9.37 W)
15 min per 2 h
2
5
13.4
23.4
28.8
31.4
0.35
(18.75 W)
Continuous
2
S
10.2
11.2
11.3
11.3
0.13
(150 W)
a Enzyme added was Spezyme ™CP cellulase (Genencor, Inc. South San Francisco, CA), Enzyme activity was determined by the manufacturer.
b MWOP contains approximately 90% Cellulose (Brooks and Ingram, 1995.)
c Theoretical maximum yield is 0.568 g ethanol per g cellulose.
d Unpaired t-tests show these results to be statistically different (p-0.0224).
Bibliography
Allison, D. G., A. D'Emanuele, and A. R. Williams. “The effect of ultrasound on Escherichia coli viability” 1996. J. Basic Microbiol. 36(1):3-11.
Atchley, A. A., and L. A. Crum. “Chapter 1: Acoustic cavitation and bubble dynamics” Ultrasound: Its Chemical, Physical, and Biological Effects. K. S. Suslick ed. VCH, New York, N.Y. 1988.
Ausubel, F. M., R. Brent, R. E. Kingston, D. D. More, J. G. Seidman, J. A. Smith, and K. Struhl. Current Protocols in Molecular Biology. Green Publishing and Wiley Interscience, New York, N.Y. 1996
Boudjouk, P. “Chapter 5. Heterogeneous sonochemistry” Ultrasound: Its Chemical, Physical, and Biological Effects. K. S. Suslick ed. VCH, New York, N.Y. 1988.
Brooks, T. A. and L. O. Ingram. “Conversion of mixed office paper to ethanol by genetically engineered Klebsiella oxytoca strain P2” 1995. Biotechnol. Prog. 11(6): 619-625
Doran, J. B., H. C. Aldrich, and L. O. Ingram. “Saccharification and fermentation of sugar canebagasse by Klebsiella oxytoca P2 containing chromosomally integrated genes encoding the Zymomonas mobilis ethanol pathway” 1994. Biotechnol. Bioeng. 44:240-247.
Gusakov, A. V., A. P. Sinitsyn, I. Y. Davydkin, V. Y. Davydkin. and O. V. Protas. “Enhancement of enzymatic cellulose hydrolysis using a novel type of bioreactor with intensive stirring induced by electromagnetic field” 1996. Appl. Biochem. Biotechnol. 56:141-153.
Hohmann, N., and C. M Rendleman. Emerging Technologies in Ethanol Production USDA Ag. Info. Bulletin no. 663. U.S. Department of Agriculture: Washington D.C. January 1993.
Ingram, L. O. and J. B. Doran. “Conversion of cellulosic materials to ethanol” 1995. FEMS Microbiol. Rev. 16:235-241
Ingram, L. O., D. S. Beall, G. F. H. Burchardt, W. V. Guimaraes, K. Ohta, B. E. Wood, and K. T. Shanmugam. “Ethanol production by recombinant hosts” 1995. U.S. Pat. No.5,424,202.
Ingram, L. O., T. Conway, and F. Altertghum. “Ethanol production by Escherichia coli strains co-expressing Zymomonas pds and adh genes” 1991. U.S. Pat. No. 5,000,000.
Kaya, F., J. A. Heitmann, Jr., and T. W. Joyce. “Cellulase binding to cellulose fibers in high shear fields” 1994. J. Biotech. 36:1-10.
Leeman, S., and P. W. Vaughn. “Cavitation phenomena” Current Trends in Sonochemisty. G. J. Price ed. Royal Society of Chemistry Special Publication No. 116. Royal Society of Chemisty: Cambridge U.K. 1992.
Nazhad, M. M., L. P. Ramos, L. Paszner, and J. N. Sadler. “Structural constraints affecting the initial enzymatic hydrolysis of recycled paper” 1995. Enz. Microb. Tech. 17:68-74.
Norman, J. C., N. J. Sell, and M. Danelski. “Deinking laser-print paper using ultrasound” 1994. TAPPI J. 77:151-158.
Price, G. J. “Introduction to sonochemistry” Current Trends in Sonochemisty. G. J. Price ed. Royal Society of Chemistry Special Publication No. 116. Royal Society of Chemistry:Cambridge U.K. 1992.
Scott, W. E. and P. Gerber. “Using ultrasound to deink xerographic waste” 1995. TAPPI J. 78:125-130.
Sell, N. J., J. C. Norman, and D. Jayaprakash. “Deinking secondary fiber using ultrasound” 1995. Progress in Paper Recycling. August p.28-34.
Sheehan, J. J. “Chapter 1. Bioconversion for production of renewable transportation fuels in the United States: a strategic perspective” Enzymatic Conversion of Biomass for Fuels Production. Himmel, M. E.; Baker, J. O.; Overend, R. P. eds. ACS Symposium Series 566. American Chemical Society: Washington D.C. 1993.
Shoh, A. “Chapter 3. Industrial applications of ultrasound” Ultrasound:Its Chemical, Physical, and Biological Effects. K. S. Suslick ed. VCH, New York, N.Y. 1988.
Suslick, K. S. “Chapter 4. Homogeneous sonochemistry” Ultrasound:Its Chemical, Physical, and Biological Effects. K. S. Suslick ed. VCH, New York, N.Y. 1988. 123-146.
Suslick, K. S. “Sonochemistry” 1990. Science. 247:1439-1441.
Suslick, K. S. “The Chemical Effects of Ultrasound” 1989. Scientific American. February p. 80-86.
Volmer, A. C., I. R. S. Maken and E. C. Everbach. “Induction of the heat shock response in Escherichia coli by the effects of acoustic cavitation from Ultrasound” Abstr. I-85, p. 317. Abstr. 96th Annu. Meet. Am. Soc. Microbiol. American Society for Microbiology, Washington D.C. 1996.
Wang, D., M. Sakakibara, N. Kaoyuki, and K. Suzuki. “Ultrasound enhanced lactose hydrolysis in milk fermentation with Lactobacillus bulgaricus” 1996. J. Chem Tech. Biotechnol. 65:86-92.
Wood, T. M. and K. M. Bhat. “Methods for measuring cellulase activities” 1988. Methods in Enzymology. 160:87-144.
Equivalents
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.
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This invention presents a method of improving enzymatic degradation of lignocellulose, as in the production of ethanol from lignocellulosic material, through the use of ultrasonic treatment. The invention shows that ultrasonic treatment reduces cellulase requirements by ⅓ to ½. With the cost of enzymes being a major problem in the cost-effective production of ethanol from lignocellulosic material, this invention presents a significant improvement over presently available methods.
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BACKGROUND OF THE INVENTION
The present invention relates to a microcapsule-containing adhesive system and method of using the same wherein the microcapsules are filled with a solvent which is capable of rendering the adhesive adherent. More particularly, the present invention relates to an adhesive-system which can be used to seal a facsimile document in an envelope before it leaves the facsimile machine so that it cannot be read without evidencing tampering.
Facsimile machines are now used almost universally in business. With the widespread use of these machines, a need has arisen to transmit documents in a strictly confidential manner. Currently this is not generally possible unless the intended recipient of the confidential document personally monitors the facsimile machine and gathers the document immediately as it is received. It has been proposed to design facsimile machines in which the transmitted document is automatically inserted into a tamper-evident envelope before it exits the facsimile machine so that the facsimile machine attendant cannot see the document and it is not necessary to stand by the machine and wait for transmission of the document.
While envelopes which are sealed with tamper-evident adhesives (so called tamper-evident envelopes) are known, the adhesives used in conjunction with these envelopes have not been satisfactory for use in a facsimile machine. The adhesives used in tamper-evident envelopes are often covered with a release film which is removed by the user immediately prior to sealing the envelope. The removal of such a release film is difficult to perform within the design limitations of conventional facsimile machines.
Another class of known adhesives which is used on most common envelopes is soluble adhesives which requires a solvent to activate the adhesive and produce its tackiness. These adhesives are also unsuitable for use in facsimile machines because a means must be provided to wet the adhesive and the adherents must be set and joined with speed and precision immediately after the solvent has been applied and the adhesive activated.
Adhesive systems employing microcapsules have been disclosed in the patent literature. One known system comprises a curable adhesive which contains rupturable microcapsules filled with a curing agent. See for example U.S. Pat. No. 4,940,852 to M. Chernack. An adhesive system containing microcapsules is also shown in U.S. Pat. No. 4,925,517 to Charbonneau et al. In this system, two substrates are temporarily adhered together with an adhesive which contains microcapsules filled with a fragrant liquid. When the adherents are pulled apart, the microcapsules break, releasing the fragrance. A further example is seen in which an adhesive coating, including a latex carrier having solvent-filled microcapsules is coated on a threaded fastener such as a bolt. When these microcapsules rupture, the solvent cures the adhesive to secure the fastener.
One of the most critical problems which arises in designing an adhesive for use in a tamper-evident envelope for use in a facsimile machine is that the envelopes or the substrate from which they are formed must be stacked together and folded and assembled with the document within the fax machine. This requires that the adhesive be non-tacky and have a low coefficient of friction. If the adhesive is tacky, the envelopes will stick together while they are stacked in the machine. If the adhesive exhibits a high coefficient of friction, it will interfere with handling the envelope and feeding the envelope through the machine as one envelope will drag another envelope along or cause misfeeds within the fax machine. While cohesives (as hereafter defined) are not tacky, they often exhibit a coefficient of friction which results in misfeeds.
Therefore, it is an object of the present invention to provide an adhesive system which is non-tacky and exhibits a low coefficient of friction, and which can be rendered adherent to provide a seal which is tamper-evident.
Summary
In accordance with the present invention, an adhesive system is provided which comprises a cohesive material dispersed in a nonadhesive material which renders the cohesive non-coherent, and a plurality of microcapsules associated with the cohesive, the microcapsules being rupturable upon the application of pressure and releasing a solvent for the cohesive which renders the cohesive adherent.
It is also an object of the present invention to provide a tamper-evident envelope having a layer of adhesive adjacent an opening in the envelope, wherein the adhesive provides cohesion between two portions of the envelope, such as the pocket and the closure flap, the adhesive system comprising a cohesive material adhered to a portion of the envelope, the cohesive material is dispersed in a nonadhesive material such that the cohesive is essentially not coherent, and a plurality of pressure-rupturable microcapsules associated with the cohesive material, the microcapsules containing a solvent, which when released from the microcapsules dissolves the cohesive material such that the cohesive material is rendered coherent. The term "cohesive" as used herein means a non-tacky material which does not adhere to foreign surfaces upon contact but which will adhere to itself. By using an activatable cohesive material in accordance with the present invention instead of an inherently tacky adhesive, the cohesive can be coated on a sheet of paper and the sheets of paper can be used in a fax machine as an envelope or to form an envelope.
It is a more particular object of the present invention to provide a method of providing tamper-evident adhesion between two adhesively-united portions of an envelope which is sealed before it leaves a facsimile machine comprising the steps of providing a substrate having an activatable cohesive coating on a portion thereof, the coating being a dried cohesive latex containing gelatin and a plurality of solvent-filled microcapsules, folding the substrate such that two areas of the substrate coated with the activatable cohesive coating overlie one another, applying pressure to rupture the microcapsules, and cause the solvent to be released such that the solvent dissolves the cohesive and forms a cohesive bond which seals the envelope, the seal being such that fiber tear of the envelope occurs before adhesive bond failure when a user opens the envelope.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example and with reference to the accompanying drawings, in which:
FIG. 1A is an adhesive of the present invention.
FIG. 1B is an adhesive of the present invention after the rupturing of the microcapsules.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Those skilled in the art will appreciate that the adhesive system of the present invention can be used on an envelope in the conventional sense, e.g., a paper having a pre-folded pocket, or on a sheet of paper which is subsequently folded to contain a document therein. In the case of a pre-folded envelope, the adhesive system can be applied around the edge of the pocket and the closure flap. In the case of a sheet of paper, it can be applied at the four side margins to seal the paper when folded. The term "envelope" as used herein shall include both the pre-folded and the unfolded variety.
The adhesive of the present invention contains a dispersed cohesive. The cohesive is a conventional polymeric material which is not tacky to the touch but which will adhere to itself. This cohesive is dispersed in a non-adherent material which renders the cohesive non-coherent. Microcapsules are associated with the system which are pressure-rupturable and filled with a solvent which is capable of dissolving the cohesive. By rupturing the microcapsules such that they release the solvent, the solvent dissolves the cohesive. It is believed that by dissolving the cohesive, the solvent produces a phase inversion whereby the cohesive moves from being a dispersed phase within the non-adherent material in which it is not coherent to a continuous phase in which it is coherent. The solvent also appears to function as a vehicle to carry the cohesive into the substrate and the mating cohesive layer so as to enhance the cohesive strength of the bond which seals the envelope. Thus, initially the adhesive system is not tacky and exhibits a low coefficient of friction so that it does not interfere with feeding the envelopes in the fax machine, but upon rupturing the capsules the adhesive is rendered adherent so that the envelope can be sealed with a tamper-evident bond.
This system will now be described in detail below with respect to the figures. It is to be understood that the forgoing general description and the following detailed description are exemplary and explanatory but are not to be restrictive of the invention. The accompanying drawings which are incorporated in and constitute a part of this invention, illustrate the embodiments of the invention, and, together with the description, serve to explain the principles of the invention in general terms. Like numerals refer to like parts throughout the disclosure.
In accordance with the present invention, as shown in FIG. 1A, the adhesive system 10 comprises a cohesive 12 interspersed in a non-adherent material 14 which blocks the cohesiveness of the cohesive and reduces the coefficient of friction during handling in the fax machine. The system is preferably a water-based, continuous phase system containing a dispersed cohesive polymer.
This non-adherent material 14 can be any continuous phase film former. One example of a useful non-adherent material is a water-soluble protein such as a gelatin, or any other film forming material which lowers the coefficient of friction of the cohesive to an acceptable level (about 0.4-0.5) so that the adhesive will not cause misfeeds during handling in a facsimile machine. The selection of the non-adhesive film former will depend on a number of factors including the surface area covered by the adhesive (e.g., as the area increases, films which have any tendency to stick or block may not be useful), the nature of the adherent, the composition of the adhesive, and the composition of this non-adherent material. Other examples of non-adherent materials include starch, water-soluble gums, polyvinyl pyrrolidone, alginates, and polyvinyl alcohol. An exemplary amount of non-adherent material is about 5 to 15% of the composition based on total solids. A preferable non-adherent material composition is typically about 5% aqueous gelatin solution dissolved in a continuous water phase, wherein there is an about 5-15%, preferably 10%, ratio of the gelatin solids to cohesive solids in the aqueous dispersion. The gelatin must be in aqueous solution in order to incorporate it into the adhesive composition.
In order to provide a tamper-evident seal, a cohesive is preferably selected which, once it is adhered to itself to seal the envelope, it causes fiber breakage to occur when the envelope is opened. Thus, the strength of the cohesive must be greater than the force required to remove or break fibers from the envelope. The selection of the particular cohesive will depend upon the nature of the paper making up the envelope. Weaker cohesives can be employed with papers exhibiting weak fiber bonding.
Representative examples of cohesives that may be used in the present invention include rubber latexes. A particularly useful cohesive is BL-3076 from Basic Adhesives, Inc., which is natural rubber latex consisting mainly of cis-polyisoprene. Many cohesives tend to exhibit high creep which would permit an envelope to be opened without evidence of tampering, it is desirable to add a high molecular or macromolecular, water dispersable material such as a resin or gelatin to the cohesive to reduce creep and enhance the adhesive strength. This way fiber tear will occur when the envelope is opened. Representative examples of resins which can be used for this purpose have a moderate glass transition temperature typically greater than about 5° C., such as ethylene-vinyl acetate copolymer. The non-adherent material may also function to reduce creep. This is the case with gelatin which can be used to shield the cohesive property of the cohesive and to reduce its creep.
The term "high molecular or macromolecular material" as used herein refers to natural and synthetic polymers preferably having a molecular weight greater than about 20,000. Representative examples of materials which can be used in the invention include vinyl acetate latices, SB-latices, formaldehyde polymers, acrylic latices, and polymeric wax dispersions.
A ratio of high molecular material to cohesive material of about 1:10 to 1:1, preferably 1:2 can be used. An exemplary amount of high molecular material is about 10°30% solids. In one embodiment, the high molecular material is EVA copolymer having a molecular weight of greater than about 70,000 used in a ratio to the cohesive of about 1:4 to 1:1, preferably 1:2.
This mixture may be applied to the substrate in any amount which is appropriate based on the composition of the substrate, etc. A typical coat weight is about 1 to 5 lbs/1300 sq. ft. This mixture produces an excellent bond which will not fail before the paper tears (i.e. the bond is such that when the envelope or other adherent is opened the paper or other substrate tears before the failure of the adhesive bond) thereby providing a tamper-evident adherent.
The adhesive system includes liquid-filled microcapsules 16. Processes for forming microcapsules are well known in the art. Any conventional process can be used herein such as coacervation, interfacial polymerization or in situ polymerization. Some common microcapsule wall formers are gelatin, ureaformaldehyde, melamineformaldehyde, polyurea, and polyureaurethane. The material and thickness of this shell material must be chosen such that it will rupture upon the application of pressure but will prevent premature release of its contents during the application of the adhesive. Preferably, the microcapsule is a polyurea microcapsule as shown in the following example.
The microcapsules contain an encapsulated solvent for the cohesive. Non-polar solvents are preferred because they dissolve the cohesive and they are compatible with microencapsulation procedures which require formation of an oil-in-water emulsion. Upon the application of pressure, the walls of the microcapsules 20 of the present invention will rupture, causing the solvent 18 to be discharged. The selection of the solvent will depend on the nature of the non-adherent material and the cohesive. The solvent must dissolve the cohesive without substantially dissolving the non-adherent material. Examples of solvents include nonpolar, non-volatile hydrocarbons having 10-18 carbon atoms. A useful solvent for a cohesive is an alkyl biphenylaliphatic hydrocarbon mix of 80% SURE SOL 290 from Koch Chemical Co. and 20% EXXSOL D110 from Exxon. When the solvent dissolves the cohesive, as shown in FIG. 1B, the cohesive is carried out of the non-adherent material, the adhesive system regains its cohesive character and is ready to be adhered to the adherent.
As a result of the rupture of the microcapsules, the gelatin 14 is dispersed in the adhesive system, along with the remains of the capsule walls 20. The cohesive system is believed to form a continuous hydrophobic phase.
The size of the microcapsules is not particularly critical to the invention and may, for example, range from about 2 to 20 microns, particularly about 8 microns. The thickness of the microcapsules walls, is not critical but should be sufficiently thick to maintain the solvent in a separate state over a prolonged period of time and thin enough to allow the microcapsules to be ruptured upon the application of the pressure. The concentration of the microcapsules in the adhesive system should be sufficient to provide an even distribution and a sufficient amount of the solvent to dissolve cohesive such that it exhibits adequate cohesive property to form a tamper-evident seal. A typical amount of microcapsules ranges from 10% to 50% based on total solids and particularly is about a weight ratio of 30% microcapsules to other coating solids.
The above adhesive system may be used to form a tamper-evident envelope. The adhesive is usually applied on a portion of the envelope adjacent an opening and/or on the closure flap. Alternatively, the adhesive can be applied around the perimeter of the document which is then folded upon itself and sealed as described next. The coating placement of the adhesive will vary with the design of the facsimile machine. The portion containing the adhesive coating is folded so that the adhesive layer on two portions of the envelope (e.g., adjacent the opening and on the closure flap) is in contact with itself. When two adhesive areas overlie one another, pressure is applied using a pressure roller or the like. The pressure causes the microcapsules to rupture. The solvent in the microcapsules is released which carries the cohesive into the porous paper and the mating cohesive layer which enables the adhesive to cohere to the other portion of the envelope. This provides a tamper-evident seal in which the cohesive bond is stronger than the fiber bond of the envelope. Therefore, when a user opens the envelope, the paper will rip before the cohesive bond fails. It will then be evident to anyone, merely by looking at the envelope, whether the contents have been previously viewed.
This tamper-evident envelope with cohesive system can be used in a facsimile machine to provide security. The envelope paper with the above described adhesive system is placed in the facsimile machine. Because of the non-tacky coating, envelopes will not adhere to each other when stacked or folded within the machine, nor will they adhere to the machine itself. After the transmission has been received, the document is placed on the envelope paper, the envelope is folded and pressure is applied to the adhesive, sealing the document. This breaks the microcapsules, releasing the solvent and enabling the adhesive system to secure the envelope. An addressee name can be printed on the outside of the folded envelope. The envelope exits the machine only after it has been sealed. In this manner, the operator of the machine, the messenger, etc. cannot view the document without opening the envelope. Since this is a tamper-evident envelope, which causes fiber-tear when the envelope is opened, the intended receiver can readily detect whether the contents have been previously viewed.
The invention is illustrated in more detail by the following non-limiting example.
EXAMPLE 1
A method of making a microcapsule-containing cohesive coating according to the present invention forms a solvent microencapsulated in polyurea capsules using the following method.
First, to prepare the external phase of the polyurea capsules, 13 grams of gum arabic were sifted into a beaker of 210 grams deionized (DI) water with good stirring. This was then covered and heated to 60° C. and held until the dispersion became clear. This was then allowed to cool to 20° C.
Next, the diluent was prepared by adding 4.7 grams diethylene triamine to 15.3 grams of DI water and stirred.
The internal phase was prepared by combining 156.0 g SURE SOL 290 from KOCH Chemical Co., 35.1 g EXXSOL D-110 from Exxon, 12.9 g BAYMICRON 2109(a biuret of hexamethylene di-isocynate) from Mobay Chemical Co., and 4.1 g SF-50 isocynate from BASF Corp (a proprietary isocynate prepolymer of 2,4 toluene diisocynate, and 1,3 toluene diisocynate. These ingredients were heated with stirring to 50° C. and emulsified but not cooked.
The external phase was added to a 600 ml stainless steel beaker. It was stirred with a Servodyne agitator at 1000 rpm. Slowly the internal phase was added at 50° C. This was then emulsified for 7 minutes. The speed was reduced to 800 rpm. Next, the diluent was added and the beaker was covered, heated to 65° C. and cured for 3 hours.
After the solvent was encapsulated the cohesive layer was formulated. The cohesive is made by mixing the following ingredients in the order specified. Note that the weights are wet weights.
0.615 parts water
0.116 parts Keestar 328 (cornstarch)
0,616 parts capsules
1,129 parts 5% gelatin solution
1.025 parts 3076 cohesive
Once uniformly mixed, the coating was applied with a Meyer rod to give a dry coat weight of about 2 to 5 pounds per 1300 square feet, preferably about 3 lbs/1300 sq. ft.
Bond formation will occur with application of a pressure above about 250 psi, preferably 450 psi.
Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
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An adhesive system comprising an activatable, non-tacky cohesive material dispersed in a nonadherent material, said nonadherent material reducing the coefficient of friction of said cohesive material and rendering said cohesive material non-coherent; and a plurality of microcapsules dispersed in said nonadherent material and said cohesive material, said microcapsules encapsulating a solvent for said cohesive and being rupturable upon the application of pressure, wherein upon the application of pressure, the microcapsules rupture and release said solvent and said solvent dissolves said cohesive material such that said cohesive material becomes coherent.
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FIELD OF INVENTION
The inventions of the this application relate to the field of electric lamps for generating light for illuminating dental work areas, and in particular, to a socket assembly especially adapted for use in dental lamps. The socket assembly releasably holds a light bulb, such as a halogen bulb, and is constructed to enable the easy replacement of the bulb that minimizes manual handling of the bulb surface, and possible risk of damage to the bulb or even potential injury to personnel replacing the bulb.
BACKGROUND
Halogen bulb lamps are an efficient light source, and are prevalent in lamps used in many industries including the dental industry. A typical halogen lamp assembly includes two socket terminals that are spring loaded to engage, hold and provide electrical contact with the bulbs. These terminal connections must be compressed to create space for positioning the halogen bulb into the lamp socket terminal and then released when the bulb is in place. Due to the high intense heat and light radiation, it is important that the surface of the halogen bulb not be contaminated with oils and moisture from the hands of the operator during placement. The presence of such contaminants can result in premature bulb failure, or even worse, bulb rupture. In an effort to avoid this problem, measures have been devised to minimize transfer of undesired contaminants. For example, operators may wear gloves during the placement of bulbs. However, gloves also pass on certain undesired residues to the bulb surface, but cause the loss of tactile feel and control thereby making the installation process more difficult.
Another issue that is involved in replacing halogen bulbs involves the spring loading of the socket terminals themselves. Due to the nature of socket terminal construction, the opening of the light socket terminal is cumbersome, as it requires three separate but simultaneous motions: the compression of the first socket terminal, the compression of the second socket terminal, and the placement of a new halogen bulb. Inserting the halogen bulb is difficult for one person limited to accomplish these three motions. The level of difficulty is only increased when the additional factor of avoiding contact with the bulb surface is factored into the routine. Another factor adding to the difficulty is the implementation of the forceful springs integrated in the socket assembly which must be pushed against via the fingers of the operator while the movements are performed.
SUMMARY
The inventors have recognized the problems and difficulties of replacing halogen bulbs in dental lamp assemblies and have developed a new dental lamp having a socket assembly that increases the ease of bulb replacement. Accordingly, a first embodiment of the present inventions pertain to a dental lamp that includes a dental lamp socket assembly having a housing with a first socket terminal and a second socket terminal movably mounted on the housing. In a specific embodiment, the first and second socket terminals each are associated with a socket base member that interact such that each socket terminal is movable with respect to the socket base member between an extended position and a retracted position. A spring associated with the socket base member urges the socket terminal into its extended position. The first socket terminal and second socket terminal have associated therewith a first and second manually operated actuator, respectively. Force applied to the actuator is transferred to the associated socket terminal to push the socket terminal into its retracted position whereby space is created for entry and positioning of the lamp bulb into the socket assembly. Moreover, the lamp socket assembly includes a first catch member that is associated with the socket terminal housing such that it releasably holds the first manually operated actuator in a retracted position. In an alternative embodiment, the socket assembly includes a second catch member that releasably holds a second manually operated actuator in its retracted position.
In using a typical embodiment of inventions of this application, force is applied to the first manually operated actuator which moves the first socket terminal into retracted position. In the retracted position, the catch member is moved to hold the manually operated actuator. While the first socket terminal is held in the retracted position by the first catch member, the operator's use of both hands is enabled to retract the second socket terminal by depressing the second manually operated actuator, and inserting a lamp bulb into the lamp socket terminal while both the first and second socket terminals are held in their retracted positions: the first socket terminal by the first catch member and the second socket terminal by the operator's hand. Once the lamp is in place, the second socket terminal is allowed to move toward its extended position, and the first socket terminal is released by the catch member to allow movement toward its extended position. Accordingly, the socket assembly equipped with the catch member allows the easy stepwise opening of the dental lamp socket terminal that avoids the need to coordinate three movements simultaneously. It also assists in counteracting the force of the springs that are loaded in the socket base members, which can be relatively high and thus difficult to manipulate solely by hand. This arrangement facilitates the operator's use of a lamp bulb holder device that avoids direct manual contact of the bulb by the operator.
In another embodiment, the manually operated actuators are levers that pivot about axes on the base of the socket terminal housing. Also, according to this specific embodiment, the catch member relates to an pawl pivotably mounted to the socket terminal housing. When the first manually operated actuator (lever) moves the first socket terminal into its retracted position, the catch member (pawl) pivots to engage the lever so as to hold the lever, and in turn, the socket terminal in the retracted position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a top, perspective view of a dental lamp socket assembly.
FIG. 2 shows a side, perspective view of the dental lamp socket assembly shown in FIG. 1 .
FIG. 3 a - c are stepwise views of a dental lamp socket assembly in which a bulb is being replaced.
FIG. 4 shows the dental lamp socket assembly mounted to a dental lamp frame.
DETAILED DESCRIPTION
Turning to the drawings, FIG. 1 shows a top perspective view of a dental lamp socket assembly embodiment 100 , that includes a housing 105 onto which a first and second socket terminal 110 , 120 and corresponding socket base members 115 , 125 are secured. First and second levers 130 , 140 (constituting manually operated actuators) are secured to the lower portion of the housing 105 ′ via pivot pins 167 , 169 . The first and second socket terminals 110 , 120 movably mounted on socket base member 115 , 125 , which are spring loaded to urge the socket terminals 110 , 120 to extend out of the corresponding base member toward extended positions. Connectors 161 , 162 for supplying electrical power to the lamp bulb is provided at opposing ends of the of the socket assembly 100 . First and second mounting screws 163 , 164 associated with the lower portion of the housing 105 ′ attach the socket assembly 100 to a dental lamp frame (shown generally in FIG. 4 ). Shield 180 is shown associated with the lower housing portion 105 ′. A pawl 135 is pivotably associated with a cross-frame member 171 of the housing 105 via pivot pin 191 . Socket base member 115 is also associated with the cross-frame member 171 at pivot pin 191 . Socket base member 125 is associated with cross-frame member 172 via connection 192 .
FIG. 2 shows a side, perspective view of the dental lamp socket assembly 100 with shield 180 removed. FIG. 2 shows more clearly how the pawl 135 is pivotably associated to engage the first lever 130 . The pawl 135 includes a pawl base 212 , a pawl arm member 215 , and a tab member 220 . Depressing the tab 220 causes the pawl arm member 215 to pivot into the desired location for engaging the lever 130 . Also, shown is the pivot pin 167 that pivotably associates the lever 130 to the housing 105 . A spring 230 maintains contact of the lever 130 with the first socket terminal 110 . Also shown in FIG. 2 is a hole 240 defined in the housing 105 ′ where screw 164 engages the housing 105 ′.
During placement of bulb as shown in FIG. 3 a - c , the operator depresses the first lever 130 , which in turn pushes back socket terminal 110 . FIG. 3 a shows the direction the operator's hand 310 depresses the lever 130 (see arrow x), and the intended direction of the pawl (see arrow y) once the lever is in the proper place. As shown in FIG. 3 b , once the lever 130 has moved back a sufficient distance, the pawl 135 has been pivoted such that the pawl arm member 215 holds the lever 130 , and in turn, the socket terminal 110 in a retracted position. With the socket terminal 110 held retracted, this frees both hands of the operator to depress the second lever 140 with one hand and manipulate the bulb 127 with the other hand, including via the use of a bulb holder device. Depressing the lever 140 causes the second socket terminal 120 to retract which then creates space for easy placement of the bulb 127 . As shown in FIG. 3 c , once the bulb 127 is in place, the socket terminal 120 is allowed to return to its extended position by releasing force on the second lever 140 . Moreover, the pawl 135 is pivoted back thereby releasing lever 130 , and the first socket terminal 110 is allowed to move back toward its extended position, whereby both first and second socket terminals 110 , 120 completely engage and hold the bulb 127 in spring biased contact at both opposing ends to provide electrical power.
FIG. 4 shows a rear side of a dental lamp 400 having a dental lamp frame 410 . A dental lamp socket assembly 100 , as described and shown in FIG. 1 is shown attached to the dental lamp frame 410 . The dental lamp 400 also includes a reflector 420 that is pivotably engaged to the dental light frame 410 , that is shown swung open to allow access to the assembly 100 . Upon placement or replacement of the lamp bulb 127 , the reflector will be closed to allow normal operation of the dental lamp 400 . The bulb generates and directs light toward the reflector which will be reflected toward a shield 430 a - b , wherein light passes through the shield 430 a - b and toward an intended dental work area.
It should be borne in mind that the housing can take a variety of shapes and configurations, and can incorporate multiple components. In typical embodiments of the present invention, the housing serves as a framework for securing the spring-loaded first and second socket terminals at an appropriate distance and location so as to receive a lamp bulb.
Although the foregoing description contains many specifics, these are not to be construed as limiting the scope of the present inventions, but merely as providing certain representative embodiments. Similarly, other embodiments of the inventions can be devised which do not depart from the spirit or scope of the present inventions. The scope of the inventions is, therefore, indicated and limited only by the respective appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the inventions, as disclosed herein, which fall within the meaning and scope of the claims, are encompassed by the present inventions. The disclosures of any references cited herein are incorporated in their entirety to the extent not inconsistent with the teachings herein.
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Disclosed herein is a dental lamp socket assembly especially adapted for use with dental lamps. The dental lamp socket assembly is configured to dramatically increase the ease at which bulbs can be placed and/or replaced in and out of the socket assembly.
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FIELD OF THE INVENTION
The present invention relates to a hydraulic damper or shock absorber adapted for use in a suspension system such as the suspension systems used for automotive vehicles. More particularly, the present invention relates to a hydraulic damper or shock absorber having a continuously variable damping characteristic which is adjustable by a stepper motor between a relatively low level of damping for a soft ride and a relatively high level of damping for a firm ride.
BACKGROUND OF THE INVENTION
A conventional prior art hydraulic damper or shock absorber comprises a cylinder which is adapted at one end for attachment to the sprung or unsprung mass of a vehicle. A piston is slidably disposed in the cylinder with the piston separating the interior of the cylinder into two liquid chambers. A piston rod is connected to the piston and extends out of one end of the cylinder where it is adapted for attachment to the other of the sprung or unsprung mass of the vehicle. A first valving system is incorporated within the piston for generating a damping force during the shock absorber's extension stroke of the piston with respect to the cylinder and a second valving system is incorporated within the piston for generating a damping force during the shock absorber's compression stroke of the piston with respect to the cylinder.
Various types of adjustment mechanisms have been developed to generate variable damping forces in relation to the speed and/or the amplitude of the displacement of the piston within the cylinder. These adjustment mechanisms have mainly been developed to provide a relatively small or low damping characteristic during the normal steady state running of the vehicle and a relatively large or high damping characteristic during vehicle maneuvers requiring extended suspension movements. The normal steady state running of the vehicle is accompanied by small or fine vibrations of the unsprung mass of the vehicle and thus the need for a soft ride or low damping characteristic of the suspension system to isolate the sprung mass from these vibrations. During a turning or braking maneuver, as an example, the sprung mass of the vehicle will attempt to undergo a relatively slow and/or large vibration which then requires a firm ride or high damping characteristic of the suspension system to support the sprung mass and provide stable handling characteristics to the vehicle. These adjustable mechanisms for the damping rates of a shock absorber offer the advantage of a smooth steady state ride by isolating the high frequency/small excitations from the sprung mass while still providing the necessary damping or firm ride for the suspension system during vehicle maneuvers causing larger excitations of the sprung mass.
The continued development of shock absorbers includes the development of adjustment systems which provide the vehicle designer with a continuously variable system which can be specifically tailored to a vehicle to provide a specified amount of damping in relation to various monitored conditions of the vehicle and its suspension system.
SUMMARY OF THE INVENTION
The present invention provides the art with a continuously variable, bi-directional adjustable hydraulic damper or shock absorber that includes the capability of adjusting the damping rate of the shock absorber between a soft ride or low damping configuration and a firm ride or high damping configuration. A stepper motor adjusts the shock absorber between these two configurations and has the capability of positioning the shock absorber in the soft ride configuration. The firm ride position or any position between these two configurations to provide the continuously variable damping for the shock absorber.
Other advantages and objects of the present invention will become apparent to those skilled in the art from the subsequent detailed description, appended claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:
FIG. 1 is a cross-sectional side view of a shock absorber incorporating the continuously variable damping capabilities in accordance with the present invention;
FIG. 2 is a cross-sectional schematic side view illustrating the shock absorber shown in FIG. 1 and the fluid flow during extension when the shock absorber is configured to provide a firm ride during extension and a soft ride during compression of the shock absorber;
FIG. 3 is a cross-sectional view similar to FIG. 2 but showing the shock absorber and the fluid flow during compression when the shock absorber is configured to provide a firm ride during extension and a soft ride during compression of the shock absorber;
FIG. 4 is a cross-sectional schematic side view illustrating the shock absorber shown in FIG. 1 and the fluid flow during compression when the shock absorber is configured to provide a firm ride during compression and a soft ride during extension of the shock absorber;
FIG. 5 is a cross-sectional view similar to FIG. 4 but showing the shock absorber and the fluid flow during extension when the shock absorber is configured to provide a firm ride during compression and a soft ride during extension of the shock absorber;
FIG. 6 is a cross-sectional view similar to FIG. 2 but showing the shock absorber and the fluid flow during extension when the shock absorber is configured to provide a soft ride during extension and compression of the shock absorber;
FIG. 7 is a cross-sectional view similar to FIG. 2 but showing the shock absorber and the fluid flow during compression when the shock absorber is configured to provide a soft ride during extension and compression of the shock absorber;
FIG. 8 is a cross-sectional view of the valving system of the piston of the shock absorber with the arrows illustrating the fluid flow during extension of the shock absorber;
FIG. 9 is a cross-sectional view of the base valving of the shock absorber with the arrows illustrating the fluid flow during extension of the shock absorber;
FIG. 10 is a cross-sectional view of the base valve similar to FIG. 9 but having the arrows illustrating the fluid flow during compression of the shock absorber.
FIG. 11 is a cross-sectional view of the valving system of the piston similar to FIG. 8 but having the arrows illustrating the fluid flow during compression of the shock absorber; and
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a shock absorber incorporating the continuously variable damping adjustment mechanism in accordance with the present invention which is designated generally by the reference numeral 10. Shock absorber 10 is a dual tube shock absorber which comprises a piston 12, a piston rod 14, a pressure tube 16 and a reserve tube 18. Piston 12 divides pressure tube 16 into an upper working chamber 20 and a lower working chamber 22. Piston rod 14 is connected to piston 12 and it extends out of pressure tube 16 and reserve tube 18 for attachment to one of the sprung or unsprung masses of the vehicle by methods known well in the art. Pressure tube 16 is filled with hydraulic fluid which moves between upper working chamber 20 and lower working chamber 22 during movement of piston 12 and piston rod 14 with respect to pressure tube 16. The flow of fluid through piston 12 between chambers 20 and 22 of pressure tube 16 is controlled by a valving system in piston 12 (see FIGS. 8 and 11) to provide for the damping of the movement of piston 12 and piston rod 14. The valving system for piston 12 will be described in greater detail later herein.
Reserve tube 18 surrounds pressure tube 16 and with pressure tube 16 defines a reserve chamber 24. Reserve tube 18 is adapted for attachment to the other of the sprung or unsprung mass of the vehicle by methods known well in the art. During the stroke of piston 12 and piston rod 14 a different volume of fluid flows into or out of upper working chamber 20 than the fluid that flows into or out of lower working chamber 22. This difference in volume is due to piston rod 14 being located only in upper working chamber 20 and not in lower working chamber 22. This volume of fluid is known as "rod volume." The "rod volume" of fluid is compensated for by a base valve assembly 26 positioned at the bottom of shock absorber 10. Base valve assembly 26 controls the fluid flow between lower working chamber 22 and reserve chamber 24. Reserve chamber 24 is partially filled with hydraulic fluid and partially filled with a pressurized gas with the level of hydraulic fluid being determined by the position of piston 12 within pressure tube 16. Base valve assembly 26 and the fluid flow through it will be described later herein.
The shock absorber as described above is well known in the art. The present invention is directed to an adjustment mechanism 30 which controls a fluid bypass between upper working chamber 20 and lower working chamber 22 to adjust the damping characteristics of shock absorber 10 between a soft ride when the fluid bypass is open and a firm ride when the fluid bypass is closed.
Referring to FIGS. 1 and 2, adjustment mechanism 30 comprises an upper transfer tube 32, an upper check valve 34, a lower transfer tube 36, a valve body 38, an upper transfer tube 40, a lower check valve 42, a lower transfer tube 44, an extension check valve assembly 46, a compression check valve assembly 48 and a valve stem 50.
Upper working chamber 20 fluidically communicates with a fluid passage 52 which extends through an upper rod guide 54 to mate with a chamber 56 formed between a lower rod guide 58 and upper rode guide 54. Upper transfer tube 32 is in communication with chamber 56 through a fluid passage 60 within which upper transfer tube 32 is located. Upper transfer tube 32 transfers fluid from chamber 56, through tube 32 and into upper check valve 34. Fluid travels through upper check valve 34, through lower transfer tube 36 and into valve body 38. Upper check valve 34 comprises a valve seat 62, a check ball 64 by and a biasing spring 66 for biasing check ball 64 against valve seat 62. Upper check valve 34 permits fluid flow from tube 32 to tube 36 and prohibits fluid flow from tube 36 to tube 32.
Lower working chamber 22 is in communication with lower transfer tube 44 through a fluid passage 68 formed within pressure tube 16 within which lower transfer tube 44 is located. Lower transfer tube 44 transfers fluid from lower working chamber 22 through tube 44 and into lower check valve 42. Fluid travels through lower check valve 42, through upper transfer tube 40 and into valve body 38. Lower check valve 42 comprises a valve seat 70, a check ball 72 and a biasing spring 74 for biasing check ball 72 against valve seat 70. Lower check valve 42 permits fluid flow from tube 44 to tube 40 but prohibits fluid flow from tube 40 to tube 44.
Valve body 38 is located within reserve chamber 24 and provides a valve chamber 76 within which valve stem 50 is rotatably disposed. Valve body 38 defines two input passages 78 and 80 and two outlet passages 82 and 84. Input passage 78 fluidically connects lower transfer tube 36 with valve chamber 76. Input passage 80 fluidically connects upper transfer tube 40 with valve chamber 76. Outlet passages 82 and 84 both fluidically connect valve chamber 76 with reserve chamber 24.
Extension check valve assembly 46 is disposed within outlet passage 82 and comprises a valve seat 86, a valve member 88, a valve guide 90 and a biasing spring 92 for biasing valve member 88 against valve seat 86. Extension check valve assembly 46 allows fluid flow from valve chamber 76 through outlet passage 82 and into reserve chamber 24 but prohibits fluid flow from reserve chamber 24 into valve chamber 76. Compression check valve assembly 48 is disposed within outlet passage 84 and comprises a valve seat 94, a valve member 96, a valve guide 98 and a biasing spring 100 for biasing valve member 96 against valve seat 94. Compression check valve assembly 48 allows fluid flow from valve chamber 76 through outlet passage 84 and into reserve chamber 24 but prohibits fluid flow from reserve chamber 24 into valve chamber 76.
Valve stem 50 is rotatably disposed within chamber 76 and it defines a fluid passageway 102 which permits fluid flow between input passages 78 and 80 and outlet passages 82 and 84 depending upon the position of fluid passageway 102 with respect to valve chamber 76. Valve stem 50 extends through valve body 38 to mate with a stepper motor 104. Stepper motor 104 is attached to shock absorber 10 by a housing 106. Housing 106 is disposed within an aperture 108 extending through reserve tube 18 and it mounts both stepper motor 104 and valve body 38. Stepper motor 104 is activated by an external source (not shown) to rotate valve stem 50 to select the damping characteristics for shock absorber 10. The input to stepper motor 104 can be manually provided or the input can be provided by a micro-computer (not shown) which simultaneously monitors the operating characteristics and conditions of the vehicle to select the damping rate for shock absorber 10 based on a pre-selected set of conditions.
The valving system provided by piston 12 and base valve assembly 26 are designed to provide a firm ride or a high damping rate. Adjustment mechanism 30 provides a fluid bypass route between chambers 20 and 22 which reduce the damping rate for shock absorber 10 when the bypass route is open.
The valving system for piston 12 is shown in greater detail in FIGS. 8 and 11. The valving system for piston 12 determines the damping characteristics for an extension movement of shock absorber 10. In the present invention, the valving system of piston 12 provides a firm damping characteristic during extension movement of shock absorber 10. Piston 12 comprises a valve body 110, a retention nut 112, an extension valve assembly 114 and a compression valve assembly 116. Valve body 110 defines an extension passage 118 and a compression passage 120 which provide the routes for fluid to flow between chambers 20 and 22. FIG. 8 illustrates an extension movement of shock absorber 10 with arrows 122 depicting fluid flow. During an extension movement of shock absorber 10, fluid in upper chamber 20 becomes pressurized and fluid in lower chamber 22 is reduced in pressure. Fluid flows out of upper chamber 20 through extension passage 118 and past extension valve assembly 114 to enter lower chamber 22. FIG. 11 illustrates a compression movement of shock absorber 10 with arrows 124 depicting fluid flow. During a compression movement of shock absorber 10, fluid in lower chamber 22 becomes pressurized and fluid in upper chamber 20 is reduced in pressure. Fluid flows out of lower chamber 22 through compression passage 120 and past compression valve assembly 116 to outer upper chamber 20.
The valving system for base valve assembly 26 is shown in greater detail in FIGS. 9 and 10. The valving system for base valve assembly 26 determines the damping characteristics for a compression movement of shock absorber 10. In the present invention, the valving system of base valve assembly 26 provides a firm damping characteristic during a compression movement of shock absorber 10. Valve assembly 26 comprises a valve body 126, retention bolt 128, a retention nut 130, an extension valve assembly 132 and a compression valve assembly 134. Valve body 126 defines an extension passage 136 and a compression passage 138 which provide routes for fluid to flow between chambers 22 and 24. FIG. 9 illustrates an extension movement of shock absorber 10 with arrows 140 depicting fluid flow. During an extension movement of shock absorber 10, fluid in lower chamber 22 experiences a drop in pressure due to the movement of piston 12. This drop in pressure in combination with the gas pressure in reserve chamber 24 causes fluid to flow out of reserve chamber 24 through extension passage 136 and past extension valve assembly 132 to enter lower chamber 22. FIG. 10 illustrates a compression movement of shock absorber 10 with arrows 142 depicting fluid flow. During a compression movement of shock absorber 10, fluid in lower chamber 22 becomes pressurized above that of reserve chamber 24 and fluid flows out of lower chamber 22 through compression passage 138 and past compression valve assembly 134.
FIGS. 2 and 3 illustrate adjustment mechanism 30 positioned to provide a firm damping rate during extension of shock absorber 10 and a soft damping rate during compression of shock absorber 10. FIG. 2 illustrates the fluid flow for an extension movement. Fluid flow from upper chamber 20 to adjustment mechanism 30 as shown by arrows 150 for a high damping conditioning during extension. Valve stem 50 is rotated to prohibit fluid flow from input passage 78 into valve chamber 76. Thus, during an extension movement of piston 12, fluid in upper working chamber 20 is pressurized forcing fluid into upper transfer tube 32, through upper check valve 34 through lower transfer tube 36 and into input passage 78. Fluid is prohibited from leaving input passage 78 due to the position of valve stem 50 and all fluid flow between upper working chamber 20 and lower working chamber 22 will occur through the valving system in piston 12 as shown in FIG. 8 and described above providing a firm damping rate during extension movements. The rod volume of fluid will flow through base valve assembly 26 from reserve chamber 24 and into lower working chamber 22 as shown in FIG. 9 and described above.
FIG. 3 illustrates the same configuration for adjustment mechanism 30 but arrows 152 illustrate fluid flow for a soft damping condition during a compression movement of shock absorber 10. When valve stem 50 is rotated to prohibit fluid flow from input passage 78 into valve chamber 76, fluid flow from input passage 80, through valve chamber 76 and into outlet passage 84 is permitted due to fluid passageway 102 in valve stem 50. Fluid flow continues through passage 84 past compression check valve assembly 48 and into reserve chamber 24. This fluid flow is in addition to the fluid flow between lower working chamber 22 and reserve chamber 24 which occurs through base valve 26 as shown in FIG. 10 and described above thus softening the damping characteristics for shock absorber 10. Fluid flow between lower chamber 22 and upper chamber 20 to offset rod volume is as shown in FIG. 11 and described above because the pressure required to open check valve assembly 48 and compression valve assembly 134 of base valve 26 is higher than the pressure required to open compression valve assembly 116.
FIGS. 4 and 5 illustrate adjustment mechanism 30 positioned to provide a firm damping during compression of shock absorber 10 and a soft damping during extension of shock absorber 10. FIG. 4 illustrates the fluid flow for a compression movement. Fluid flow from lower chamber 22 to adjustment mechanism 30 is shown by arrows 154 for a firm damping condition during compression. Valve stem 50 is rotated to prohibit fluid flow from input passage 80 into valve chamber 76. Thus, during a compression movement of piston 12, fluid in lower working chamber 22 is pressurized forcing fluid into lower transfer tube 44, through lower check valve 42, through upper transfer tube 40 and into input passage 80. Fluid is prohibited from leaving input passage 80 due to the position of valve stem 50 and all fluid flow between lower working chamber 22 and reserve chamber 24 will occur through base valve 26 as shown in FIG. 10 and described above providing a firm damping rate during compression movements. Fluid flow from lower working chamber 22 to upper working chamber 20 will occur through the valving system of piston 12 as shown in FIG. 11 and described above because the pressure required to open compression valve assembly 134 of base valve assembly 26 is higher than the pressure required to open compression valve assembly 116.
FIG. 5 illustrates the same configuration for adjustment mechanism 30 but arrows 156 illustrate fluid flow for a soft damping rate during an extension movement of shock absorber 10. When valve stem 50 is rotated to prohibit fluid flow from input passage 80 into valve chamber 76, fluid flow from input passage 78, through valve chamber 76 and into outlet passage 82 is permitted due to fluid passageway 102 in valve stem 50. Fluid flow continues through passage 82 past extension valve assembly 46 and into reserve chamber 24. This fluid flow is in addition to the fluid flow between upper working chamber 20 and lower working chamber 22 which occurs through piston 12 as shown in FIG. 8 and described above thus softening the damping characteristics for shock absorber 10. Fluid flow between reserve chamber 24 and lower chamber 22 to offset rod volume is as shown if FIG. 9 and described above.
FIGS. 6 and 7 illustrate adjustment mechanism 30 positioned to provide a soft damping rate during an extension movement of shock absorber 10 and a soft damping rate during a compression movement of shock absorber 10. Valve stem 50 is rotated to provide fluid flow from input passage 78, through valve chamber 76 and into outlet passage 82 while simultaneously providing fluid flow from input passage 80, through valve chamber 76 and into outlet passage 84.
FIG. 6 shows fluid movement, arrows 158, during an extension movement of piston 12. Fluid in upper working chamber 20 is pressurized forcing fluid into upper transfer tube 32, through upper check valve 34, through lower transfer tube 36, through input passage 78, through passageway 102, through outlet passage 82, past extension check valve 46 and into reserve chamber 24. Fluid flow will also travel through passageway 102 through outlet passage 84, past compression check valve 48 and into reserve chamber 24. This fluid flow is in addition to the fluid flow between upper working chamber 20 and lower working chamber 22 which occurs through piston 12 as shown in FIG. 8 and described above thus softening the damping characteristics for shock absorber 10. Fluid flow between reserve chamber 24 and lower chamber 22 to offset rod volume is as shown in FIG. 9 and described above.
FIG. 7 shows fluid movement, arrows 160, during a compression movement of piston 12, fluid in lower working chamber 22 is pressurized forcing fluid into lower transfer tube 44, through lower check valve 42, through upper transfer tube 40, through input passage 80, through passageway 102, through outlet passage 84, past compression check valve 48 and into reserve chamber 24. Fluid flow will also travel through passageway 102 through outlet passage 82, past extension check valve 46 and into reserve chamber 24. This fluid flow is in addition to the fluid flow between lower working chamber 22 and reserve chamber 24 which occurs through base valve 26 as shown in FIG. 10 and described above thus softening the damping characteristics for shock absorber 10. Fluid flow between lower chamber 22 and upper chamber 20 to offset rod volume is as shown in FIG. 11 and described above because the pressure required to open check valve assemblies 46 and 48 and compression valve assembly 134 of base valve 26 is higher than the pressure required to open compression valve 116.
While the present invention has been described as having three positions for valve stem 50, it can be seen that by making stepper motor 104 turn valve stem 50 in smaller increments, virtually any intermediate damping characteristic for shock absorber 10 in a compression movement and an extension movement can be generated.
While the above detailed description describes the preferred embodiment of the present invention, it should be understood that the present invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims.
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A shock absorber includes the typical fluid valving in the piston and in the base valve assembly which is designed to provide a firm damping characteristic for the shock absorber. A stepper valve assembly includes a bypass fluid passage between the upper working chamber and the reserve chamber which when opened provides a soft damping characteristic during an extension movement of the shock absorber. The stepper valve assembly also includes a bypass fluid passage between the lower working chamber and the reserve chamber which when opened provides a soft damping characteristic during a compression movement of the shock absorber. The stepper valve assembly selectively opens and closes the bypass fluid passages to adapt the shock absorber to changing vehicle conditions.
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BACKGROUND OF THE INVENTION
This invention relates to improvements in rebound texturizing or bounce crimping of thermoplastic multifilament yarns.
The synthetic textile industry is greatly interested in texturizing synthetic thermoplastic continuous filament yarns. As produced, these yarns are relatively straight and have little bulk. It is desired that they be bulked, so that the yarns resemble more closely yarns spun from staple fiber. Customarily, these yarns are bulked by bending or crimping the individual filaments in the yarn and heat setting the yarn while the filaments are bent or crimped.
Fluid under pressure has been used extensively in the texturizing of synthetic thermoplastic yarns. See, for example, U.S. Pat. Nos. 3,097,412 and 3,373,470.
A basic advance in the texturizing of thermoplastic yarn was a technique known as a rebound or bounce crimping process which yields strikingly improved results as far as crimp quality is concerned.
Bounce crimping entails hurling yarn, by a heated fluid, through a jet in a continuous stream-like flow against a foraminous surface upon which the yarn impinges and from which the yarn instantaneously rebounds or bounces. The impact upon the foraminous surface axially buckles and crimps individual filaments of the yarn while the heated fluid passes through the foraminous surface. The texturized yarn without tension and substantially by rebound interia progresses away from the crimping zone and is retained in an essentially tensionless state until the crimp has set. Then the yarn is wound upon a storage spool or package.
Thermoplastic yarn texturized by the foregoing bounce crimping process possesses, among other things, exceptional covering capability and a high degree of resiliency as disclosed in Miller et al U.S. Pat. No. 3,686,848, issued Aug. 29, 1972.
The basic process and apparatus for practicing the process is featured in Clarkson U.S. Pat. No. 3,665,567 issued May 30, 1972. In brief summary, the Clarkson structure entails feeding a yarn through a tubular passage by a jet of steam and hurling the yarn longitudinally against a foraminous screen. The yarn is thereby crimped or texturized and rebounds laterally through a passage from which it drops down to a receiver for heat setting. The steam primarily passes through the foraminous screen and is collected, although some of the steam may pass laterally through the yarn outlet passage along with the texturized yarn.
Notwithstanding singular advantages provided the synthetic textile industry by the above-noted Clarkson bounce crimping process, room for significant advances remains.
For example, the bounce crimped yarns known heretofore have not been used widely or at all in some of the specialty yarn markets and the production of more voluminous yarns containing bounce crimped filaments wound result in an even greater area of utility in the textile industry.
SUMMARY OF THE INVENTION
Accordingly, a primary object of the present invention is to provide improvements in thermoplastic yarn rebound texturizing methods and products.
Another more particular object of the present invention is to provide methods for producing more voluminous rebound texturized or bounce crimped yarns.
Yet another object of the present invention is to produce rebound texturized or bounce crimped yarns of greater utility in the textile industry.
In accordance with one aspect of the present invention, an improved rebound texturizing or bounce crimping method is provided. The general method includes (a) longitudinally advancing first and second thermoplastic multifilament yarns in a stream of heated fluid advancing longitudinally of the yarns, the first yarn being advanced at a rate at least twice the rate of advance of the second yarn; (b) hurling the yarns toward a foraminous surface by means of the stream of fluid while passing at least part of the stream of fluid through the foraminous surface; (c) impinging the advancing yarns on the foraminous surface with sufficient force to induce compression crimps in the filaments of at least the first yarn; (d) instantaneously rebounding the yarns from the surface in a continuous strand-like stream, the filaments of the first yarn being entangled with each other and the first yarn being entangled with the second yarn, the filaments of the first yarn protruding laterally from the second yarn in loop configurations of rebound texturized filament sections; and (e) guiding the entangled rebounded yarn away from the foraminous surface in a generally tensionless state.
In this process, the slower fed yarn becomes a core and the faster fed yarn becomes a cover in the completed product which is of the type referred to in the trade as an effect yarn product. Although such a product is a unitary yarn, the core is sometimes referred to generally as a core yarn and the cover is sometimes referred to generally as an effect yarn. Since the lengths of the cover filaments contained in a given length of product must necessarily be much greater than the lengths of core yarn filaments there, these extra lengths of cover yarn filaments must be oriented laterally with respect to the axis of the yarn. The arrangement may be visualized generally as one in which rebound texturized loop portions of cover yarn filaments protrude laterally from the assembly of core yarn filaments all along the length of the product.
In the products of this invention, the filaments of the cover or effect yarn are crimped and they are entangled not only with the other filaments of the cover yarn but also in varying degrees with filaments of the core yarn. The filaments of the core yarn are also entangled in varying degrees with each other and the filaments of the cover or effect yarn, and they may be individually crimped, although the degree of crimp in the core yarn filaments may be rather small in some instances. The effect yarn is also in varying degrees entangled with or wrapped around the core yarn. In the overall products of the invention, the filaments are so locked in by these entanglements that unitary yarn structures are provided, susceptible of being handled satisfactorily by conventional textile fabric making machines. In other words, the combination of the different entanglements and the bounce crimping provide an intimate and substantially immobile relationship between the effect yarn and the core yarn such that there is essentially no slippage of the effect yarn on the core yarn. This is highly desirable for textile operations.
In another aspect of the present invention, a slub yarn effect is also achieved by slowing, either regularly or randomly, the core yarn feed so that slubs or nodules of overfed effect yarn also appear on the final product.
Control over the character of the yarns produced may also be exercised by controlling other aspects of the process and the inputs to the process.
For example, the input yarns may vary as to number, composition, overall size, and filament size and shape.
In accordance with another aspect of the present invention, it has been found that increasing the speed of the effect yarn or cover yarn decreases the entanglement of the effect yarn with the core yarn.
It has also been found that input yarn filament size has a noticeable effect on the degree of entanglement achieved in the process, and that, in general, the lower the denier per filament, the better the entanglement will be.
Further, the overfeed ratio has been found to have a gross and pronounced effect on overall yarn product bulk and denier. The greater the overfeed ratio, the greater will be the lengths of effect yarn filament loops or increments which must protrude laterally from the core and the greater will be the number of loops or increments per unit length to provide enhanced volume, compaction and bulk, and the greater will be the denier (weight per unit length) of the yarn product.
Moreover, it has been found that increased restriction or resistance on the texturized yarn emerging from the actual crimping zone or chamber increases entanglement of the effect yarn with the core yarn and entanglement of the effect yarn with itself. In practice this restriction or controlling of axial compaction is imposed by resistance forces applied downstream from the actual crimping zone or chamber to inhibit discharge of yarn product. The physical results of increased restriction is the increased entanglement of the effect yarn filaments both with the core yarn filaments and also with other effect yarn filaments. This latter effect contributes to the visual indication of a compact yarn.
Other objects, aspects and advantages of the present invention will become apparent to one skilled in the art in view of the following description of the preferred embodiments when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view, partially broken away, of a bounce crimping apparatus for texturizing synthetic thermoplastic continuous filament yarns;
FIG. 2 is a cross sectional view taken along section line 2--2 in FIG. 1 and discloses a bounce crimping chamber and lateral outlet tube according to a preferred embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The improvement of the subject invention is with respect to rebound texturizing or bounce crimping generally according to the above referenced U.S. Pat. Nos. 3,665,567 and 3,686,848, as well as U.S. Pat. Nos. 3,859,696; 3,859,697 and 3,887,971, all of which are assigned to the assignee of the present invention. The entire disclosure of these patents are hereby incorporated by reference as though set forth at length.
Briefly, however, the basic bounce crimping of the subject invention may be appreciated by reference to FIG. 1 which discloses an elevational view, partially broken away, of a bounce crimping apparatus 10.
A first multi-filament synthetic thermoplastic effect yarn 12 is fed from a supply package (not shown) to a first driven godet roll 16 with skewed separator roll 14 and then to a second driven godet roll 20 with skewed separator roll 18. Godet rolls 16 and 20 may be heated and rolls 18 and 20 advance the yarn at a much greater speed than do rolls 14 and 16 so that the yarn 12 is drawn between the two sets of rolls. From roll 18 the effect yarn 12 advances to a yarn texturizing station indicated generally by reference character 22.
A second pre-drawn multi-filament synthetic thermoplastic core yarn 13 is fed from a supply package (not shown) to a driven godet roll 15 and about a skewed separator roll 17 and a roll 19 to the texturizing station 22. The second yarn 13 may also pass through a suitable conventional means 25 to cause a periodic slowing in advancement of the second yarn. The frequency and duration of the retardation induced by the means 25 may be random, as desired. Instead of using pre-drawn core yarn, undrawn core yarn may be used, for example, utilizing a drawing means 13a shown schematically but which is a draw roll arrangement similar to the draw rolls 14, 16, 18, 20 drawn for the effect yarn 12. The texturized product yarn passes from texturizing station 22 into a heating chamber 24 where the yarn is heated in a loose mass substantially free from tension. The yarn passes downstream of the heating chamber 24 into a cooling chamber 26 in the form of a strand over idler rolls 27, 28 and advances over idler roll 36 to a standard takeup mechanism where the yarn is wound in a package 38 for storage and shipment.
Referring to FIG. 2 the yarn texturizing station 22 includes an adapter housing 40 having a longitudinally extending central bore 42. The external lower end of the adapter housing 40 is fashioned with a convex configuration surrounding the bore 42. A member 44 having a foraminous surface, such as a screen, closes the lower end opening of the bore 42 to the passage of yarn while simultaneously permitting steam to longitudinally pass through the openings in the screen 44.
The adapter housing 40 is fitted with a coaxial collar 46 which serves as an adapter for connection of the bore 42 with a steam exhaust conduit 48. By the provision of the exhaust conduit, steam passing through the screen 44 may be drawn off by a blower (not shown).
The above described texturizing station 22 serves to texturize or crimp thermoplastic yarn by the technique of "rebound" or "bounce" crimping. In this connection, thermoplastic yarns 12, 13 are drawn into the texturizing station, heated by steam and advanced into the bore 42 by an improved orifice and steam introduction assembly to be discussed in detail hereinafter. As the live process steam picks up the yarns 12, 13 it hurls the yarns longitudinally with great force downwardly through the bore 42 toward the screen 44 at a centermost point of the concave portion of the screen. The bulk of the steam passes through screen 42 while the composite yarn rebounds or bounces from the screen 44 instantaneously in a continuously moving strand-like stream 21 flowing upwardly and to the left, past a relatively thin side wall 50 within the adapter housing and into a lateral exit opening. From the improved conveying and compacting means 68 the yarn 21 is deposited into the heating chamber 24. Instead of steam, other heated fluids under pressure may be used. For example, heated compressed air or nitrogen may be used.
as noted in FIG. 1, the heating chamber 24 consists of an outer sleeve of insulation 70 which surrounds a steam chamber 72, which in turn encompasses an inner cylindrical yarn treating chamber 74. Steam is circulated through chamber 72 to heat the wall about the yarn treating chamber 74, and consequently to heat the yarn contained within the chamber 74.
The rebounded texturized yarn 21 falls into the yarn receiving chamber 74 in a condition substantially free of longitudinal tension. As the yarn 21 is withdrawn from the cooling chamber 26 by the takeup mechanism, the loose mass of yarn within the heating chamber 24 progresses downwardly through the heating chamber.
To further assist in heating the yarn within chamber 74, hot air bleed tubes 76 are disposed vertically within the chamber 74 and are provided with apertures spaced at regular intervals throughout the longitudinal extent thereof. Air heated in the steam chamber 72 is blown from the apertures within bleed tubes 76 into chamber 74 to circulate through the mass of yarn within the chamber 74 and insure uniform heating of the texturized yarn.
As previously noted, immediately beneath the heating chamber 24 there is disposed a cooling chamber 26 comprising the bottom leg of a J-tube formed by the heating chamber 24 and the cooling chamber 26. The yarn passes through the cooling chamber 26 still in a loose untensioned mass. To assist in cooling the yarn, two air bleed tubes 78 are disposed inside and on opposite sides of the cooling chamber 26. Air at room temperature is blown through the cooling tubes 78 and out through apertures within the tubes along the longitudinal length thereof to circulate through the yarn mass to cool the yarn and exit through an opening 80 within a top portion of the cooling chamber 26.
Not until this point when the yarn has been fully heat set and cooled is the texturized yarn subject to longitudinal tension. As noted in FIG. 1, the yarn 21 is now withdrawn from the cooling chamber 26 over a baffle 82 and through an eyelet 84 which tends to remove loose tangles in the yarn. To further remove any loose tangles a series of tension vanes 86, 88 90 and 92 are provided. These vanes are simply thin pieces of sheet metal shaped to close the chamber and pivot at hinges 94, 96, 98 and 100, respectively, so that gravity will pivot the tension vanes against a wall 102 of the chamber.
The effect yarn 21 then advances in a substantially linear form over idler rolls 27, 28 and 36 to be wound upon a package 38 in a conventional manner as previously noted.
As specifically illustrated in FIG. 2, a jet texturizing apparatus 101 forming a part of the yarn texturizing station 22 is disclosed. The jet texturizing apparatus 101 includes an upwardly projecting cylindrical portion 103 of the yarn texturizing adapter housing 40 and a readily replaceable orifice member or plug 104 coaxially positioned within the interior of the cylindrical projection 103.
The orifice plug 104 includes a central longitudinally extending passage 122 operable for receiving yarns 12, 13. The plug 104 is further fashioned with a first frustoconical exterior surface 106 adjacent an upper end thereof and a second frustoconical surface 108 adjacent a lower end of the orifice plug. A conical extension of the first frustoconical surface 106 is spaced from a conical extension of the second frustoconical surface 108 by a small distance. This spacing operably forms an annular steam jetting orifice in a manner to be discussed hereinafter.
The replacement orifice plug 104 is designed to be coaxially received within the extension 103 of the yarn texturizing housing wherein the first frustoconical surface 106 of the orifice plug intimately mates with a first frustoconical ledge 112, machined upon an interior surface of the cylindrical projection 103. A cylindrical bore 114 is machined into the projection and terminates into a second frustoconical ledge 116 lying upon an extension of the conical surface of ledge 112. The second frustoconical ledge 116 provides a smooth transition between the bores 114 and 42.
The axial extent of bore 114 is designed with respect to the axial extent of the orifice plug 104 such that the second frustoconical surface 108 of the plug lies in a mutually adjacent but spaced posture with respect to the second frustoconical ledge 116. The small spacing provided between the second frustoconical surfaces 108 and 116 at 118 provides an annular aperture or orifice for the uniform introduction of steam into the bore 42.
The orifice plug 104 is rigidly held within the projecting cylindrical extension 103 of the yarn texturizing housing 40 by the provision of a backing plug 120 having a central longitudinal aperture 122 for guiding thermoplastic yarns 12, 13 into the orifice. Exteriorly the plug 120 is provided with threads 124 which mate with interior threads 126 fashioned upon the internal surface of the extension 103. By the provision of this threaded engagement, the plug 103 may be tightly torqued down to abutting engagement with the orifice plug 104 to securely and rigidly mount the first and second frustoconical surfaces 106 and 112 in mating engagement.
When the orifice plug 104 is mounted in an operative position, as illustrated in FIG. 2, within the bore 114 of the texturizing housing extension 103, an internal or first process steam plenum chamber 128 is formed. This internal plenum chamber 128 is defined by the bore 114 of the extension 103, an external cylindrical surface of the orifice plug 104, the first frustoconical surfaces 106 and 112 and the second frustoconical surfaces 108 and 116. This internal steam plenum chamber 128 is operable to uniformly deliver steam through the annular orifice at 118 and without producing an undesired erratic and/or swirling flow.
Referring now specifically to FIG. 2 a heated fluid adapter is disclosed and is designed to be received upon the texturizing housing extension 103 at an elevational location coincident with that of the orifice plug 104. The heating fluid adapter unit includes an annular housing 132 having a central annular bore 134 which forms in combination with the exterior surface of the yarn texturizing housing 103 a steam plenum chamber exterior of the housing.
Steam is delivered into plenum chamber through an adapter fitting (not shown) of a conventional design which is connected to a source of live process steam through a regulator valve (not shown).
The annular housing 132 is further provided with an upper annular chamber 140 which receives a first sealing O-ring 142 and a lower annular chamber 144 for receiving a second sealing O-ring 146. The upper and lower sealing assemblies serve to sealingly engage the exterior surface of the texturizing housing extension 103 and prevent the passage of steam from the plenum chamber into the ambient environment.
A plurality of apertures are radially fashioned through the texturizing housing extension 103 and serve to fludically communicate the exterior steam plenum chamber and the interior steam plenum chamber 128 between the orifice plug 104 and the bore 114, as previously noted.
As specifically illustrated in FIG. 2, an outlet and compaction means 68 comprises a cylindrical tube 154 having a circular cross section and is designed to normally extend at a first end 155 into and mate with the adapter body 40. In this connection, a central longitudinal axis of the tube 154 at the first end 155 will intersect and lie at right angles to the central longitudinal axis of the bore 42 of adapter 40. The other end 156 of the outlet tube is bent downwardly approximately 90° with respect to the first end such that the central longitudinal axis of the tube at the second end extends at a right angle with respect to the central longitudinal axis of the tube at the first end thereof.
The internal diameter of the circular tube 154 is slightly greater than an arcuate upper surface 157 of a lateral outlet arch fashioned within the adapter 40. Accordingly, texturized yarn 21 rebounding from the foraminous surface 44 smoothly enters the outlet tube 154 without becoming tangled by sharp edges or corners between the outlet tube 154 and the adapter housing 40. This smooth transition zone minimizes the occurrence of a blocking or jamming tendency of the texturized yarn 21 at the outlet of the adapter 40.
The internal cross sectional area of the tube 154 is not vastly greater than that of the adapter yarn outlet opening defined by the screen 44 at the bottom and the arch 157 at the top. This feature is important in that it has been found desirable to inhibit buckling of the yarn back and forth upon itself as the yarn moves along the tube 154. The rebounding yarn from the crimping zone tends to assume the general size and shape of the adapter outlet opening, and if this is very much smaller than the passage into which the yarn is moving there is a tendency for buckling along the length of the yarn to cause yarn to eject intermittently and to produce irregularities in the product. It has been found that such difficulties may be avoided if the internal cross sectional area of the tube 154 is in the range of from about 11/2 to about 2 times the area of the adapter outlet opening. Under these conditions, there is little tendency for lateral buckling of the yarn; instead it may compress axially to substantially fill the cross sectional area of the tube 154 so that reshaping of the filament assembly takes place smoothly and regularly.
The arcuate, approximately 90°, bend in the outlet tube 154 provides resistance to the passage of texturized yarn 21 through the tube. In this connection, as the yarn 21 encounters increased resistance provided by the curve in outlet tube 154, the yarn increases in axial compaction as schematically represented at points 160, 162 and 164. The outlet tube 154 progressively imparts axial compaction of the texturized yarn 21 to provide a loose plug of crimped fibers. This axial compression downstream of the crimping chamber facilitates the overall yarn texturizing process and desirable entanglement of the effect yarn as discussed above.
This advantageous axial compression of the texturized effect yarn 21 within the outlet tube may be enhanced yet further by the provision of back pressure apparatus 166 positioned adjacent the outlet end of the tube 154. More particularly, the tube 154 may be fashioned with an oblong opening or slot 168 in the surface thereof for permitting the entrance of a leaf spring 170. The spring 170 is mounted upon the tube 154 by a mounting collar 172 and set screw 174.
The leaf spring 170 extends within the tube 154 substantially across the axial passageway thereof and facilitates the back pressure maintaining character of the outlet tube as initially provided by the arcuate configuration thereof. The back pressure provided by leaf spring 170 further adds axial compaction to the yarn as it progresses in a loose mass through the outlet tube 154 and falls into the heat treating chamber 24.
The presence of the spring 170 is particularly advantageous from the standpoint of enhancing the versatility of the apparatus. Where different sizes of yarns are to be processed, the resistance to movement offered by the bent tube alone may vary significantly in dependence upon the size of the yarn, but the spring 170 tends to make reasonably uniform the overall resistance to passage of the composite yarn. The spring is very light in weight, so that its inertia characteristics do not contribute significantly toward the production of gross non-uniformities in the yarn being processed.
Although much of the description herein focuses on processes and resulting product yarns where there are only two input yarns to the bounce crimping apparatus, other effects can be achieved by using more than two yarns.
Input yarn filament shape has some effect on crimp, with shapes other than round cross-sections frequently exhibiting more pleasing textures.
Any synthetic thermoplastic multifilament yarn may be used according to the present invention. These include polyolefins, e.g., polypropylene; polyamides, e.g., poly(caprolactam); poly(2-pyrolidone) and poly(hexamethylene adipamide); polyesters, e.g., polyethylene terephthalate; acrylics, e.g., polyacrylonitrile; and cellulose esters, e.g., cellulose acetate. The effect and core yarns may be of one or more of these materials, and the materials of the effect and the core yarns may be the same or different. Polyolefins and polyamides may give particularly pleasing effects.
The thermoplastic multifilament yarns may be drawn or undrawn prior to texturizing. Preferably when polypropylene is used, the yarn is drawn at a suitable ratio, e.g., between about 2:1 and 5:1.
As indicated above, the cover or effect yarn is fed or advanced to the texturizing zone at a rate of at least twice that of the core yarn. Overfeed ratios of effect yarn to core yarn may be much higher, e.g., 100:1. More typically, and preferably herein, the overfeed ratio is between about 5:1 and 50:1.
The speed of the effect yarn as it is fed to the texturizing zone may vary considerably. Typically, the speed of the input effect yarn to the texturizing chamber may be between about 1,000 and about 10,000, typically between about 3,000 and about 6,000 feet per minute.
EXAMPLES
Using the apparatus and method described above in connection with FIGS. 1 and 2, a number of novel effect yarns were produced according to the present invention. (A 50 mesh screen was used in the texturizing chamber.) Data for the runs is given in the TABLE below.
TABLE__________________________________________________________________________Example 1 2 3 4 5 6 7 8__________________________________________________________________________Draw ratio (rolls 20,18: 3:1 3:1 3:1 3:1 3:1 3:1 3:1 3:1rolls 16,14)Effect yarn speed (ft/min) 3600 4320 2475 3090 4350 4350 4350 4350Roll (16) steam (psi) 12.4 12.4 12.4 12.4 12.4 12.4 12.4 12.4Texturizing chamber 100 100 100 100 100 100 100 100steam (psi)Effect yarn polymer (12) PP.sup.1 PP PP PP PP PP PP PPCore yarn polymer (13) PP PP PP PP PP PP PP PPRestrictor (170) No No No No Yes No Yes YesFeed ratio.sup.2, effect yarn: 5.1:1 28.1:1 9.2:1 9.4:1 7.8:1 7.8:1 2.9:1 5.2:1core yarnDenier of effect yarn (12) 900/70.sup.3 900/70.sup.3 900/70.sup.3 900/70.sup.3 600/140 600/140 600/140 600/140Denier of core yarn (13) 400/70 300/70 400/70 400/70 400/70 400/70 400/70 400/70__________________________________________________________________________Example 9 10 11 12 13 14 15 16 17__________________________________________________________________________Draw ratio (rolls 20,18: 3:1 3:1 3:1 3:1 3.5:1 3.5:1 3:1 3:1 3:1rolls 16,14)Effect yarn speed (ft/min) 5334 5334 5334 4350 4317 4317 4350 5334 4320Roll (16) steam (psi) 12.4 12.4 12.4 12.4 12.7 12.7 12.4 12.4 12.4Texturizing chamber 100 100 100 100 100 100 100 100 100steam (psi)Effect yarn polymer PP PP PP PP PA PA PP PP PPCore yarn polymer PP PP PP PP PA.sup.4 PA PP PP PPRestrictor (170) No No No No Yes No No No YesFeed ratio, effect 13.3:1 16.8:1 22.2:1 10.6:1 27.2:1 27.2:1 10.6:1 10.7:1 23.4:1yarn:core yarnDenier of effect yarn 600/140 600/140 600/140 550/140 1800/140 1800/140 600/140 600/140 1300/70.sup.5Denier of core yarn 400/70 400/70 400/70 400/70 1100/104 1100/140 400/70 400/70 400/70__________________________________________________________________________ .sup.1 PP=Polypropylene ##STR1## .sup.3 3 × 300/70 yarn (all deniers aproximate) .sup.4 PA=Polyamide (nylon 66) .sup.5 900/70 plus 400/70 yarns
The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protected herein, however, is not to be construed as limited to the particular forms disclosed, since these are to be regarded as illustrative rather than restrictive. Variations and changes may be made by those skilled in the art without departing from the spirit of the present invention.
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Improvements in thermoplastic yarn rebound texturizing method are provided by advancing a plurality of continuous filament yarns at different speeds into a stream of heated fluid advancing longitudinally of the yarns, hurling the yarns toward a foraminous surface by means of the stream of fluid while passing at least part of the stream of fluid through the surface, impinging the advancing yarns on the foraminous surface with sufficient force to induce compression crimps in the filament of at least the faster fed yarn, instantaneously rebounding the yarns from the foraminous surface, and continuously controlling the actual compaction of the yarn as it moves away from the crimping zone. The rates of advancement of the yarns respective to the fluid stream are such that at least one yarn is introduced into the system at a rate at least twice the rate of the other.
The result is a novel yarn in which the more slowly fed yarn serves as a core and the more rapidly fed yarn serves as a cover or "effect" yarn with its filaments providing rebound texturized loops protruding laterally from the core. The crimped filaments are entangled with one another and the effect yarn is entangled with the core to give the yarn product stability and integrity, permitting it to be processed into fabrics and the like on conventional equipment. An additional slub yarn effect may be achieved by slowing the core yarn feed, thus periodically forming overfed yarn slubs or nodules on the effect yarn product.
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FIELD OF THE INVENTION
[0001] The present invention is directed to apparatus for monitoring and obtaining energy information in an electric power distribution system and in particular to a multiprocessor unit that provides circuit protection and extended monitoring and energy information features having a graphical display to display power related parameters in graphical form, and which may be controlled from a local control panel and/or a remote location using its communication features.
BACKGROUND OF THE INVENTION
[0002] In certain factory power distribution systems, relatively high-voltage power (i.e. greater than 1,000 volts) provided by the power company generation station may be stepped down to lower voltage power using a transformer. The lower voltage power may then be distributed around the factory to various power equipment such as, motors, welding machinery and large computers. Such power a distribution systems of this type may be divided into branches, where each branch may supply power to a portion of the factory. The power distribution system is protected by installing low voltage fuses or circuit breakers in each branch so that a fault, such as a short circuit in a piece of equipment, supplied by one branch should not affect the power distributed to equipment coupled to the other branches. In addition to detecting large overcurrent conditions relating to short circuit faults, industrial circuit breakers may also detect long-time overcurrent conditions and excessive ground current. Relatively simple circuit breakers may be thermally tripped as a result of heating caused by an overcurrent condition, and is considered to be better for detecting relatively low level overcurrent conditions since it measures the cumulative heating effect of the low-level overcurrent condition over some time period. Such breakers may, however, respond too slowly to provide effective protection against high-current short circuit conditions.
[0003] Another type of circuit breaker monitors the current level being passed through the branch circuit and trips the breaker when the current exceeds a predefined maximum value. Such circuit breakers may include a microcontroller coupled to one or more current sensors. The microcontroller continually monitors the digitized current values using a curve which defines permissible time frames in which both low-level and high-level overcurrent conditions may exist. If an overcurrent condition is maintained for longer than its permissible time frame, the breaker is tripped. Although this breaker type is believed to provide protection against both long-time and short time overcurrent conditions, if it does not calculate Root-Mean Square (RMS) current values, it may erroneously trip the circuit when a nonlinear load, such as a welding machine, is coupled to the branch that it is protecting. Nonlinear loads may produce harmonics in the current waveform. These harmonics may distort the current waveform, causing it to exhibit peak values which are augmented at the harmonic frequencies. When the microcontroller, which assumes a sinusoidal current waveform, detects these peaks, it may trip the circuit breaker even though the heating effect of the distorted waveform may not require that the circuit be broken or otherwise interrupted.
[0004] Since the above described circuit breakers monitor overcurrent conditions, other types of faults such as over or under voltage conditions and phase imbalances may be missed unless or until they result in an overcurrent fault. Circuit protection for such faults may require special purpose line monitoring and relaying equipment, separate from the overcurrent breakers.
[0005] Another issue with certain existing circuit breakers involves the time required to restore the branch to operation once the breaker has tripped. For transient faults, such as a power surge during an electrical storm, a technician must go onto the factory floor, locate the tripped breakers and reset them. Depending on the technician's experience and knowledge, this may take a few minutes or a few hours. In this instance, however, the delay may be reduced by using a circuit breaker with an automatic recloser.
[0006] Faults caused by the equipment that is powered by the branch may be more difficult to locate. Certain circuit breakers may provide little if any information on the type of fault that caused the breaker to trip. Thus, the technician may need to install power monitors on each piece of equipment to determine if the fault was a long-time low-level overcurrent condition caused, for example, by a defective motor winding, or an intermittent short circuit fault. Such faults may take several days to locate and correct.
[0007] Another issue with existing low-voltage circuit breaker systems concerns the lack of effective backup protection if the circuit breaker fails to trip. This is more of a concern with microcontroller based trip units than with the older thermal trip units. In general, effective backup protection may include a fuse, in series with the branch line, which blows at a short-circuit current slightly higher than the short-circuit current of the breaker. If the microcontroller or any of its associated circuitry fails, a lower-level overcurrent condition may damage the distribution system and/or the equipment being protected before the backup fuse is blown.
[0008] Increasingly, the consumption of electrical power by a load is also monitored. Such power monitoring has been known at least since about the mid-1980s. As such, equipment manufacturers are increasingly using electronic circuit protection devices with circuit breaker units. These electronic circuit protection units may sample signals to provide various information, such as current, voltage, power factor, harmonics, kilowatt hours, var-hours, va-hours, instantaneous power, phase balance/imbalance, phase loading in relation to historical numbers and a percentage of maximum level. Moreover, these values may be stored to form a database.
[0009] Such information was only available in alpha-numeric displays at the power meter or electronic trip unit. An example of a graphical display interface for displaying power information of an electronic circuit device is U.S. Pat. No. 5,675,745 issued to King et al. and assigned to Siemens Energy & Automation, Inc., which is the assignee of the present application. Other forms of display were accomplished by down loading the relevant data to another computer either directly or in a network configuration.
SUMMARY OF THE INVENTION
[0010] The present invention relates to an Energy Information Device (EID) for an Energy Information System and more specifically for the graphical interface generally for a circuit breaker which senses and measures voltage, current and frequency and determines a variety of conditions of the circuit breaker based on these measurements. The EID counts and stores the number of times the circuit breaker trips for any reason. The EID has a display to provide a combination of waveform and histogram displays to the user and a keyboard to allow the user to set a trip parameters and to control display modes. The EID also has a communications port for access of the measured parameters and conditions of the circuit breaker as well as control of the energy management unit through a remote terminal.
[0011] According to yet another aspect of the invention, an energy information system for use with a circuit breaker coupled between a power source and a load, the energy information system comprising: sensing means for sensing at least one of i) a voltage, and ii) a current flowing between the power source and the load through the circuit breaker; detecting means for detecting transitions of a sensed voltage; counting means for counting a number of times the circuit breaker trips and interrupts the current flow between the power source and the load; measuring means for i) measuring the current flow through the circuit breaker when the circuit breaker trips and interrupts the current flow between the power source and the load and ii) determining a plurality of energy related parameters including a measure of at least one of the voltage, the current and the frequency based on an output from the detecting means, between the power source and the load; input means for accepting a user input, the user input controlling at least one of the circuit breaker and a display means; the display means for displaying at least one of the plurality of conditions of the circuit breaker responsive to the input means; and communication means coupled to the input means for selectively communicating at least one of the plurality of energy related parameters to a remote terminal.
[0012] According to yet another aspect of the invention, the energy information system described above, wherein the counting means includes: a mechanical counter means for determining a first count value based on a total number of times the circuit breaker trips; an interruption level counter means for determining a second count value, the second count value indicating a current range flowing between the power source and the load when the circuit breaker trips; and a fault counter means for determining a third count value, the third count values indicating a count of a fault condition that trips the circuit breaker.
[0013] According to yet another aspect of the invention, the energy information system described above, further comprising security means for selectively allowing access to control the energy information system.
[0014] Still another aspect of the invention, the energy information system described above, wherein said security means is a password entered using said input means.
[0015] Yet another aspect of the invention, the energy information system described above, wherein the sensing means further comprises: converting means for converting the voltage of the power source to a lower voltage; biasing means for biasing the lower voltage above a ground potential by a predetermined bias value to produce a full-wave biased voltage, wherein the measuring means processes the full-wave biased voltage to determine the plurality of conditions of the circuit breaker.
[0016] According to yet another aspect of the invention, the energy information system described above, wherein the biasing means further comprises: a generating means for generating a stable reference voltage; and a buffer means coupled to the generator for buffering the stable reference voltage and generating the predetermined biased value.
[0017] According to yet another aspect of the invention, the energy information system described above, wherein the sensing means has a voltage input range from about 50% to 125% of the voltage of the power source.
[0018] According to yet another aspect of the invention, the energy information system described above, wherein the display means displays the plurality of conditions in one of a plurality of languages based on a user selection.
[0019] According to yet another aspect of the invention, the energy information system described above, further comprising memory means for storing a date of manufacture of the circuit breaker.
[0020] According to yet another aspect of the invention, the energy information system described above, wherein the date of manufacture is at least one of i) displayed on the display means and ii) sent to the remote terminal by the communication means.
[0021] According to yet another aspect of the invention, the energy information system described above, wherein the plurality of energy related parameters includes at least one of i) an energy demand based on at least one of the current and the voltage sensed by the sensing means over a predetermined period of time and ii) a plurality of RMS parameters measured over a range of harmonics of a fundamental frequency of the power source.
[0022] Still another aspect of the invention, the energy information system described above, wherein the predetermined period of time is between about 1 and 90 minutes, the period of time selectable by the user through at least one of the input means and the communications means.
[0023] According to yet another aspect of the invention, the energy information system described above, wherein the demand is determined by calculating according to the following equation:
∑ n = 1 T PRG ( I A + I B + I C 3 ) T PRG = AmpDemand
[0024] where T PRG is a programmable demand period, and I A , I B and I C are phase currents for phases A, B and C, respectively.
[0025] According to yet another aspect of the invention, the energy information system described above, wherein the energy information system is adaptable for mounting within the circuit breaker.
[0026] According to still another aspect of the invention, the energy information system described above, wherein the energy information system is field installable within the circuit breaker. According to yet another aspect of the invention, an energy information system for use with a circuit breaker coupled between a power source and a load, the energy information system comprising: a sensor to sense at least one of i) a voltage and ii) a current flowing between the power source and the load through the circuit breaker; a transition detector to detect transitions of a sensed voltage from the sensor; a counter coupled to the sensor to count a number of times the circuit breaker trips and interrupts the current flow between the power source and the load; a energy information controller coupled to the sensor and counter to measure the current flow through the circuit breaker when the circuit breaker trips and interrupts the current flow between the power source and the load and for measuring a plurality of related parameters, including a measure of at least one of the voltage, the current and the frequency based on an output from the transition detector; an input device coupled to the energy information controller to enter a user input for controlling at least one of the circuit breaker and a display; the display coupled to the energy information controller to display at least one of the plurality of power related parameters responsive to the user input; and a communication port coupled to the energy information controller to selectively communicate at least one of the plurality of power related parameters to a remote terminal.
[0027] According to yet another aspect of the invention, the energy information system described above, wherein the counter further includes: a mechanical counter to determine a first count value based on a total number of times the circuit breaker trips; an interruption level counter to determine a second count value, the second count value indicating a current range flowing between the power source and the load when the circuit breaker trips; and a fault counter to determine a third count value, the third count value indicating a count of a fault condition indicative of a circuit breaker trip.
[0028] According to yet another aspect of the invention, the energy information system described above, wherein the second count value is a plurality of count values of respective ranges of current flows, the ranges of current flows selected from the group consisting of i) the current flow being less about than 100% of a trip rating of the circuit breaker; ii) the current flow being between about 100% and 300% of the trip rating of the circuit breaker; iii) the current flow being between about 300% and 600% of the trip rating of the circuit breaker; iv) the current flow being between about 600% and 900% of the trip rating of the circuit breaker; and v) the current flow being greater than about 900% of the trip rating of the circuit breaker.
[0029] Still another aspect of the invention, the energy information system described above, wherein the third count value includes at least one of the group consisting of: i) an overload fault count value; ii) a short time fault count value; iii) an instantaneous fault count value; and iv) a ground fault count value.
[0030] According to yet another aspect of the invention, the energy information system described above, further comprising a security controller to selectively allow access to the energy information system by the input device.
[0031] According to yet another aspect of the invention, the energy information system described above, wherein the sensor comprises: a voltage transformer to convert a line voltage of the power source to a voltage lower than the line voltage; and a voltage shifter to bias the lower voltage above a ground potential by a predetermined voltage to produce a full-wave biased voltage signal, wherein the energy information controller measures the full-wave biased voltage signal to determine the plurality of energy related parameters.
[0032] Still another aspect of the invention, the energy information system described above, wherein the transition detector has a voltage input range from about 50% to 125% of the voltage of the power source.
[0033] According to yet another aspect of the invention, the energy information system described above, wherein the communication port comprises at least one of an RS-232 communication port and an RS-485 communication port, each of the communication ports providing for upload and download of data between the remote terminal and the energy information controller.
[0034] Yet another aspect of the invention, the energy information system described above, wherein the display displays the plurality of energy related parameters in one of a plurality of languages based on a user selection, the selection made through at least one of the input device and the communication port.
[0035] According to still another aspect of the invention, the energy information system described above, further comprising a memory for storing a date of manufacture of the circuit breaker.
[0036] According to yet another aspect of the invention, the energy information system described above, wherein the date of manufacture is at least one of displayed on the display and sent to the remote terminal through the communication port.
[0037] According to yet another aspect of the invention, the energy information system described above, wherein the plurality of energy related parameters includes at least one of i) an energy demand based on at least one of the current and the voltage sensed by the sensor over a predetermined period of time and, ii) a plurality of RMS parameters measured over a range of harmonics of a fundamental frequency of the power source.
[0038] According to still another aspect of the invention, the energy information system described above, wherein the range of harmonics includes up to at least about a 19th harmonic of the fundamental frequency.
[0039] Yet another aspect of the invention, the energy information system described above, wherein the predetermined period of time is between about 1 and 90 minutes, the period of time selectable by the user through at least one of the input device and the communication port.
[0040] According to yet another aspect of the invention, the energy information system described above, wherein the demand is determined by calculating according to the following equation:
∑ n = 1 T PRG ( I A + I B + I C 3 ) T PRG = AmpDemand
[0041] where T PRG is a programmable demand period, and I A , I B and I C are phase currents for phases A, B and C, respectively.
[0042] According to still another aspect of the invention, the energy information system described above, wherein the demand calculation is performed automatically about once a second.
[0043] Still another aspect of the invention, the energy information system described above, wherein the energy information system is adaptable for mounting within the circuit breaker.
[0044] Yet another aspect of the invention, the energy information system described above, wherein the energy information system is field installable within the circuit breaker.
[0045] Yet another aspect of the invention, the energy information system for use with a circuit breaker coupled between a power source and a load, the energy information system comprising: a sensor to sense at least one of i) a voltage and ii) a current flowing between the power source and the load through the circuit breaker; a transition detector to detect transitions of a sensed voltage from the sensor; a voltage shifter coupled to the sensor to bias the voltage above a ground potential by a predetermined voltage to produce a full-wave biased voltage waveform; a counter to determine i) a first count value based on a total number of times the circuit breaker trips; ii) a second count value indicating a current range flowing between the power source and the load when the circuit breaker trips, the current range based on percentage of a trip rating of the circuit breaker; and iii) a third count value indicating a count based on a predetermined fault condition of the circuit breaker; an energy information controller coupled to the sensor, the counter, the transition detector and the voltage shifter, the energy information controller measuring i) the current flow through the circuit breaker when the circuit breaker trips and ii) the full-wave biased voltage waveform to determine the plurality of energy related parameters of the circuit breaker; an input device coupled to the energy information controller to enter a user input for controlling at least one of the circuit breaker and a display; a memory to store a date of manufacture of the circuit breaker; the display coupled to the energy information controller to display at least one of i) the plurality of conditions and ii) the date of manufacture of the circuit breaker responsive to the user input, the plurality of energy related parameters including a) an energy demand; and b) a plurality of RMS parameters measured over a range of harmonics of a fundamental frequency of the power source based on at least one of the voltage, the current and the frequency over a predetermined period of time, a security controller to selectively allow access of the energy information system by the input device; and a communications port including at least one serial communications port, the communications port coupled to the energy information controller to selectively communicate with a remote terminal; wherein the communication port provides for upload and download of data between the remote terminal and the energy information controller.
[0046] Still another aspect of the invention, an energy information system mounted within a circuit breaker coupled between a power source and a load, the energy information system comprising: a sensor to sense at least one of i) a voltage and ii) a current flowing between the power source and the load through the circuit breaker, the sensor having a voltage input range from about 50% to 125% of the voltage of the power source; a voltage transformer to convert a line voltage of the power source to a voltage lower than the line voltage; a transition detector to detect transitions of a sensed voltage from said sensor and to generate a transition signal, said transition detector comprising: i) a filter having an input coupled to an output of the voltage transformer to filter an AC signal from the transformer; ii) a comparator coupled to the filter to compare a filtered output of the filter to a voltage; iii) an amplifier for amplifying an output of the comparator; and iv) an inverter for inverting an output of the amplifier and producing a signal representative of a frequency of the AC signal; a voltage shifter to bias the lower voltage above a ground potential by a predetermined voltage to produce a full-wave biased voltage waveform; a mechanical counter to determine a first count value based on a total number of times the circuit breaker trips; an interruption level counter to determine a second count value, the second count value indicating a current range flowing between the power source and the load when the circuit breaker trips, the interruption level counter includes a plurality of count values of respective ranges of current flows, the ranges of current flows selected from the group consisting of i) the current flow being less than about 100% of a trip rating of the circuit breaker; ii) the current flow being between about 100% and 300% of the trip rating of the circuit breaker; iii) the current flow being between about 300% and 600% of the trip rating of the circuit breaker; iv) the current flow being between about 600% and 900% of the trip rating of the circuit breaker; and v) the current flow being greater than about 900% of the trip rating of the circuit breaker; a fault counter to determine a third count value, the third count value indicating a count of a fault condition that trips the circuit breaker, the fault condition being at least one of: i) an overload fault;ii) a short time fault; iii) an instantaneous fault; and iv) a ground fault; an energy information controller coupled to the sensor, the transition detector, the interruption level counter, and the voltage shifter, the energy information controller measures i) the current flow through the circuit breaker when the circuit breaker trips and interrupts the current flow between the power source and the load, and ii) the full-wave biased voltage to determine a plurality of energy related parameters using an AC signal frequency based on the transition signal; a keypad coupled to the energy information controller to enter a user input, the user input for controlling at least one of the circuit breaker and a display; a memory to store a date of manufacture of the circuit breaker; the display coupled to the energy information controller to display at least one of i) the plurality of energy related parameters and ii) the date of manufacture, of the circuit breaker responsive to the user input, the plurality of energy related parameters including: a) an energy demand calculated according to the following equation:
∑ n = 1 T PRG ( I A + I B + I C 3 ) T PRG = AmpDemand
[0047] where T PRG is a programmable demand period, and I A , I B and I C are phase currents for phases A, B and C, respectively and b) a plurality of RMS parameters measured over a range of harmonics of a fundamental frequency of the power source based on at least one of the voltage, the current and the frequency, over a predetermined period of time, the range of harmonics including up to at least about a 19th harmonic of the fundamental frequency; a security controller for selectively allowing access of the energy information system by the keypad; and a communication port including at least one of an RS-232 communication port and an RS-485 communication port, the communication ports coupled to the energy information controller to selectively communicate at least one of the plurality of energy related parameters and the date of manufacture to a remote terminal; wherein the communication ports provide for upload and download of data between the remote terminal and the energy information controller; the display displays the plurality of energy related parameters in one of a plurality of languages based on a user selection through at least one of the keypad and the communication port; and the energy information system is field installable within the circuit breaker.
[0048] According to yet another aspect of the invention, an energy information device for use with a circuit breaker having a trip unit, the energy information device coupled between a power source and a load, the device comprising: a plurality of current sensors having an input coupled to respective ones of a plurality of power lines between the power source and the load; a plurality of transformers coupled between the respective ones of the plurality of power lines and an analog to digital converter (ADC); a transition detector having an input coupled to an output of one of the plurality of transformers; an override circuit coupled to an output of the plurality of current sensors, an input of a power supply and a first microprocessor; a trip circuit having a first input coupled to an output of the override circuit; the first microprocessor further coupled to a first programmable read only memory (PROM), a second input of the trip circuit, and a second microprocessor; and the second microprocessor further coupled to an output of the transition detector, an output of the ADC, a clock circuit, a second PROM and a random access memory (RAM).
[0049] According to still another aspect of the invention, the energy information device described above, further comprising: a first digital input/output (I/O) interface coupled to the first microprocessor; and a second digital I/O interface coupled to the second microprocessor.
[0050] Yet another aspect of the invention, the energy information device described above, further comprising a liquid crystal display (LCD) coupled to the second microprocessor.
[0051] Still another aspect of the invention, the energy information device described above, further comprising a test connector coupled to the second microprocessor.
[0052] According to yet another aspect of the invention, the energy information device described above, further comprising a rating plug coupled to the first microprocessor.
[0053] According to yet another aspect of the invention, the energy information device described above, further comprising: a first signal conditioner coupled between the plurality of current sensors and the first microprocessor, and a second signal conditioner coupled between 1) the plurality of current sensors and the plurality of transformers and ii) the ADC.
[0054] Yet another aspect of the invention, the energy information device described above, wherein the transition detector comprises: a filter having an input coupled to the output of one transformer to filter an AC signal from the transformer; a comparator coupled to the filter to compare a filtered output of the filter to a voltage; an amplifier for amplifying an output of the comparator; and an inverter for inverting an output of the amplifier and producing a signal representative of an AC signal frequency, wherein transition information is supplied to the second microprocessor based on the AC signal frequency.
[0055] According to still another aspect of the invention, an energy information device described above for use with a circuit breaker having a trip unit, the energy information device coupled between a power source and a load, the device comprising: a signal conditioner coupled to a plurality of power lines between the power source and the load providing conditioned signals based on an input signal representative of a current flowing between the power source and the load; an override circuit coupled to an output of the signal conditioner; a filter coupled to a first output of the override circuit to filter the first output of the override circuit; a microprocessor coupled to an output of the filter; a memory coupled to the microprocessor; and a trip circuit coupled to an output of the microprocessor and a further output of the override circuit, and generating a trip signal for the trip unit based on at least one of i) the further output of the override circuit and ii) the output of the microprocessor.
[0056] According to yet another aspect of the invention, the energy information device described above, further comprising a rating plug coupled to the microprocessor.
[0057] According to still another aspect of the energy information device described above, wherein the input signal is a differential input signal and the override circuit converts the differential input signal into a single ended output signal.
[0058] Still another aspect of the invention, an energy information device for use with a circuit breaker having a trip unit, the energy information device coupled between a power source and a load, the device comprising: a first amplifier coupled to a plurality of power lines between the power source and the load, providing first amplified signals based on a first input signal representative of a plurality of currents flowing between the power source and the load; a second amplifier coupled to the plurality of power lines between the power source and the load, providing second amplified signals based on a second input signal representative of a respective plurality of voltages provided by the power source to the load; a transition detector coupled to an output of the second amplifier to detect a transition of a voltage signal based on one of the plurality of voltages, and generating a transition signal used in determining a frequency of the voltage signal; a first analog-to-digital converter (ADC) coupled to an output of the first amplifier to generate a first digital output signal representative of the plurality of currents based on an offset value; a second ADC coupled to an output of the second amplifier to generate a second digital output signal representative of the plurality of voltages based on the offset value; an offset generator coupled to the first amplifier, the second amplifier, the first ADC and the second ADC, and generating the offset value; a first clock generator for generating a clock signal to control a sample timing of the first ADC and the second ADC; a microprocessor coupled to the first ADC and the second ADC, said microprocessor processing the first and second digital output signals of the first and second ADC, respectively; a second clock generator coupled to the microprocessor for generating a system time base; a first memory coupled to the microprocessor, the memory containing an executable program for the microprocessor; a second memory coupled to the microprocessor for storing data from and providing data to the microprocessor; and a communications port coupled to the microprocessor for remote access of the microprocessor.
[0059] According to yet another aspect of the invention, the energy information device described above, wherein the transition detector comprises: a filter having an input coupled to one output of the second amplifier to filter the voltage signal based on one of the plurality of voltages from the second amplifier; a comparator coupled to the filter to compare a filtered output of the filter to a voltage; an amplifier for amplifying an output if the comparator; and an inverter for inverting an output of the amplifier and producing transition information relating to a voltage signal frequency, wherein the transition information is supplied to the microprocessor, which determines the voltage signal frequency.
[0060] According to yet another aspect of the invention, the energy information device described above, wherein the communication port is at least one of an RS-232 port and an RS-485 port.
[0061] According to yet another aspect of the invention, the energy information device described above, wherein the communication port is coupled to a remote computer.
[0062] According to yet another aspect of the invention, an energy information management method for use with a circuit breaker coupled between a power source and a load, the method comprising the steps of: (a) sensing at least one of a voltage and a current flowing between the power source and the load through the circuit breaker; (b) counting a number of times the circuit breaker trips and interrupts the current flow between the power source and the load; (c) measuring the current flow through the circuit breaker when the circuit breaker trips and interrupts the current flow between the power source and the load; (d) determining a plurality of conditions of the circuit breaker; (e) accepting a user input, the user input for at least one of controlling the circuit breaker and displaying the plurality of conditions of the circuit breaker; (f) displaying at least one of the plurality of conditions of the circuit breaker responsive to the user input; and (g) communicating at least one of the plurality of conditions to a remote terminal.
[0063] According to yet another aspect of the invention, the method described above, further comprising the steps of: (h) converting a line voltage of the power source to a voltage lower than the line voltage; and (i) biasing the lower voltage above a ground potential by a predetermined voltage to produce a full-wave biased voltage, wherein the plurality of conditions of the circuit breaker are determined from the full-wave biased voltage.
[0064] According to still another aspect of the invention, an energy information management method for use with a circuit breaker coupled between a power source and a load, the method comprising the steps of: (a) sensing at least one of a voltage, and a current flowing between the power source and the load through the circuit breaker; (b) detecting at least two transitions of a sensed voltage and determining a corresponding frequency; (c) converting the voltage of the power source to a lower voltage, (d) biasing the lower voltage above a ground potential by a predetermined voltage to produce a full-wave biased voltage; (e) counting a number of times the circuit breaker trips and interrupts the current flow between the power source and the load; (f) measuring the current flow through the circuit breaker when the circuit breaker trips and interrupts the current flow between the power source and the load; (g) determining a plurality of conditions of the circuit breaker based on at least one of the voltage and the current sensed in Step (a), and for the frequency determined in step (b);(h) accepting a user input for controlling the circuit breaker; (i) displaying at least one of the plurality of conditions of the circuit breaker device responsive to the input accepted in Step (h); and (j) communicating at least one of the plurality of conditions to a remote terminal.
[0065] According to yet another aspect of the invention, a method for graphically displaying a menu for selection and viewing of the load related parameters of a load connected to an AC load control device, comprising the steps of: (a) monitoring the load related parameters of the load connected to the AC load control device; (b) displaying on a graphical display device a menu of a plurality of indicia representing the monitored load related parameters; (c) scrolling through each indicia on said menu; and (d) selecting an item from said menu thereby causing the load related parameters relating to the said indicia to appear on said graphical display device as a signal representation.
[0066] According to still another aspect of the invention, a method for graphically displaying a menu for selection and viewing of the load related parameters of a load connected to an AC load control device, comprising the steps of: (a) monitoring the load related parameters of the load connected to the AC load control device; (b) displaying on a graphical display device a menu of a plurality of indicia representing the monitored load related parameters; (c) scrolling through each indicia on said menu; and (d) selecting an item from said menu thereby causing the load related parameters relating to the said indicia to appear on said graphical display device in signal representation and histogram forms simultaneously.
[0067] According to still another aspect of the invention, a graphical energy information display system having a menu for user selection of energy related information for an AC load control device, comprising: a device for monitoring AC electrical load usage of a load; a graphical display device connected to said device for monitoring AC electrical load usage, said graphical display device adapted so as to graphically display indicia and at least one parameter of the AC electrical load usage of the load said parameters being displayed as a signal representation; menu means for displaying a plurality of selections on said graphical display device, each of said plurality of selections representing at least one parameter of the AC electrical load usage; and menu selection means for selecting at least one of said plurality of selections so as to cause said graphical display device to graphically present the signal representing said at least one parameter of the AC electrical load usage associated with said selections.
[0068] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said menu means displays said indicia on said graphical display device in a hierarchical format.
[0069] According to still another aspect of the invention, a graphical energy information display system described above, wherein said menu selection means comprises a user selectable keypad input for scrolling through said indicia displayed by said menu means onto said graphical display device, thereby enabling a user to select and view the said at least one parameter of the AC electrical load usage of a load.
[0070] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said user selectable keypad input comprises a touch input keypad.
[0071] According to still another aspect of the invention, a graphical energy information display system described above, wherein said user selectable keypad input comprises a touch input device overlaid onto said graphical display device.
[0072] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said graphical display device comprises an LCD display.
[0073] According to still another aspect of the invention, a graphical energy information display system described above, wherein said LCD display is at least 128 pixels square.
[0074] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said graphical display device comprises an Electrofluorescent display.
[0075] According to yet another aspect of the invention, a graphical energy information display system described above, wherein the graphical display device simultaneously produces multiple corresponding power related signals representing the same parameter for a plurality of different indicia of the AC electrical load usage.
[0076] According to still another aspect of the invention, a graphical energy information display system having a menu for user selection of energy related information for an AC load control device, comprising: a device to monitor AC electrical load usage of a load; a graphical display device connected to said device to monitor AC electrical load usage, said graphical display device adapted so as to graphically display indicia and at least one parameter of the AC electrical load usage of the load said parameters being displayed as a waveform; menu structure to display a plurality of selections on said graphical display device, each of said plurality of selections representing at least one parameter of the AC electrical load usage; menu selection structure to select at least one of said plurality of selections so as to cause said graphical display device to graphically present the power related signal representing said at least one parameter of the AC electrical load usage associated with said selections; and a circuit protective device to interrupt electrical power to the load responsive to said at least one parameter of the AC electrical load usage.
[0077] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said circuit protective device is a circuit breaker.
[0078] According to still another aspect of the invention, a graphical energy information display system described above, wherein the graphical display device essentially simultaneously produces graphic images of the processed signals representing voltage and current by signal representations, and harmonics and phase balance in a histogram format.
[0079] According to yet another aspect of the invention, a graphical energy information display system having a menu for user selection of energy related information for an AC load control device, comprising: a circuit protective device for interrupting electrical power to a load; means for monitoring AC electrical load usage of a load comprising a first means for controlling said circuit protective device and a second means for producing a plurality of signals representative of at least one of a current, a voltage and a power related characteristic of the load; menu means for displaying a plurality of indicia on a graphical display device, each of said plurality of indicia representing at least one parameter of the AC electrical load usage; menu selection means for selecting at least one of said plurality of indicia so as to cause the graphical display device to graphically present said at least one parameter of the AC electrical load usage associated with said indicia; and a graphical display device connected to said means for monitoring AC electrical load usage and adapted so as to graphically display at least one parameter of the AC electrical load usage of the load as a signal representation, said graphical display device comprising an energy information means connected to said second means for receiving and processing and storing said plurality of signals and for producing graphics related output image signals, and a display means connected to said energy information means and adapted to receive said graphics related output image signal for producing graphic images which are viewable by the user.
[0080] According to still another aspect of the invention, a graphical energy information display system described above, wherein said graphical display device comprises an LCD display.
[0081] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said LCD display is at least 128 pixels square.
[0082] According to yet another aspect of the invention, a graphical energy information display system described above, wherein said graphical display device comprises an Electrofluorescent display.
[0083] According to yet another aspect of the invention, a graphical energy information display system described above, wherein the graphical display device simultaneously produces multiple corresponding signal representations representing the same parameter for a plurality of different indicia of the AC electrical load usage.
[0084] According to yet another aspect of the invention, a graphical energy device simultaneously produces graphic images of the processed signals representing voltage and current by signal representations, and harmonics and phase balance in a histogram format.
BRIEF DESCRIPTION OF THE DRAWINGS
[0085] [0085]FIG. 1A is a schematic diagram, partly in block diagram form of a power distribution system which includes a circuit breaker containing an embodiment of the present invention.
[0086] [0086]FIG. 1B is a block diagram which illustrates the data communications interconnections of selected ones of the circuit breakers shown in FIG. 1A.
[0087] [0087]FIG. 2A is a block diagram, partly in schematic diagram form of a portion of the circuit breaker suitable for use in the system shown in FIGS. 1A and 1B.
[0088] [0088]FIGS. 2B and 2C are block diagrams of circuit boards, partly in schematic diagram form detailing the bus structure and interconnection of the components of FIG. 2A.
[0089] [0089]FIG. 2D is a diagram showing the interconnection of the circuit boards detailed in FIGS. 2B and 2C.
[0090] [0090]FIG. 3 is a drawing showing the interconnection of the EID of FIG. 2A and a trip unit.
[0091] [0091]FIG. 4 is an exemplary front panel of one of the EID shown in FIGS. 2A.
[0092] [0092]FIGS. 5A through 5D are representative graphs and histograms of the present invention.
[0093] [0093]FIGS. 6A through 6F are various displays showing exemplary menu displays and an exemplary waveform display of the EID shown in FIG. 2A.
[0094] [0094]FIGS. 7A through 7J are various displays of settings and conditions of the EID shown in FIG. 2A.
[0095] [0095]FIGS. 8A and 8B are graphs of current versus time which are useful in describing the operation of the EID of FIG. 2A.
[0096] [0096]FIG. 9A through 9C are perspective drawings which show the installation of the EID of FIG. 2A in a circuit breaker.
[0097] [0097]FIG. 10 is a schematic of an exemplary transition detector of the EID of FIG. 2A.
[0098] [0098]FIGS. 11A and 11B are flow charts outlining an exemplary Sampling Task of the present invention.
[0099] [0099]FIG. 12 is a flow chart outlining an exemplary Initiate Sampling Task of the present invention.
[0100] FIGS. 13 A- 13 C are flow charts outlining an exemplary Meter Task of the present invention.
[0101] [0101]FIGS. 14A and 14B are flow charts outlining an exemplary LCD Scroll Task of the present invention.
[0102] [0102]FIG. 15 is a flow chart outlining an exemplary Events Task of the present invention.
[0103] [0103]FIG. 16 is a flow chart outlining an exemplary Keypad Task of the present invention.
[0104] [0104]FIG. 17 is a flow chart outlining an exemplary Display Task of the present invention.
[0105] [0105]FIG. 18 is a flow chart outlining an exemplary RS232 Task of the present invention.
[0106] [0106]FIG. 19 is a flow chart outlining an exemplary RS485 Task of the present invention.
[0107] [0107]FIG. 20 is a flow chart outlining an exemplary Transmit Message Task of the present invention.
[0108] [0108]FIG. 21 is a flow chart outlining an exemplary SPI Message Task of the present invention.
[0109] [0109]FIG. 22 is a flow chart outlining an exemplary Error Task of the present invention.
[0110] FIGS. 23 A- 23 I are schematic diagrams of the Energy Information circuit board of the present invention.
[0111] [0111]FIGS. 24A and 24B are schematic diagrams of the Protective circuit board of the present invention.
DETAILED DESCRIPTION
Overview
[0112] [0112]FIG. 2A shows a dual processor circuit breaker and an energy information system, in which two processors are implemented using respective microprocessor circuits 214 and 222 . The Protective microprocessor 214 monitors the current flowing through the three-phase power lines 202 a , 202 b and 202 c of an exemplary three-line system to detect overcurrent conditions and to trip the circuit breaker 116 (shown in FIG. 1A) immediately if a large overcurrent is detected or if a relatively small but sustained overcurrent is detected using a programmable delay time. In a four-line system a neutral power line is also available. In the following explanation, a four-line system will be assumed although a single phase system or a three-line multiphase system is equally applicable.
[0113] The EID Protective microprocessor 214 monitors the potential developed across the power lines 202 a , 202 b , 202 c and 202 n and the current flowing through the power lines 202 a , 202 b , 202 c and 202 n . From these values, the Protective microprocessor 214 calculates the power flowing through the lines and the frequency of the power signal. Based on these parameters, the Protective microprocessor 222 can trip the breaker, update a variety of stored parameters or change the state of an alarm output signal. An alarm signal may be used to actuate an alarm device, such as a light and/or a buzzer, or it may be used, through a trip unit 302 (shown in FIG. 3), to open the circuit breaker 116 (shown in FIG. 1A).
[0114] The Energy Information/Communications microprocessor 222 is capable of logging minima and maxima for various monitored parameters, including the overcurrent conditions, also known as pickup events and trip events. Referring to FIG. 1B, a remote host computer 140 and/or personal computers (PC) 115 , 117 and 119 may obtain the logged information. The computer 140 may be coupled to multiple trip units to obtain the continuing status of the electric power distribution system. As is shown in FIG. 4, much of the logged information may be monitored using a local front panel display unit. The host computer 140 and PCs 115 , 117 , 119 may also be used to control respectively the operation of the circuit breakers 114 , 116 , 118 .
[0115] Referring to FIG. 2A, all input and output signals to and from the Energy Information/Communications microprocessor 222 and Protective microprocessor 214 , including the operational power signals, are electrically isolated from the outside circuitry to prevent damage to the trip unit circuitry.
Detailed Description of the Exemplary Embodiment of the Invention
[0116] [0116]FIG. 1A is a simplified diagram of an electrical power distribution system. In FIG. 1, all of the power lines include three-phase lines and a neutral line, even though only one line is shown. FIG. 1A high voltage source 110 , which may be a power company substation, provides a relatively high voltage electrical signal to the primary winding of a transformer 112 . The secondary winding of the transformer provides, for example, three-phase low voltage to a factory power distribution system. The lower stepped-down voltage is distributed around the factory through respective step-down transformers 124 , 126 , 128 and 130 to provide power to equipment represented as respective loads 125 , 127 , 129 and 131 .
[0117] The power distribution system is protected by multiple circuit breakers 114 , 116 , 118 , 120 and 122 . In this configuration, the circuit breakers 116 , 118 , 120 and 122 each protect the system from faults occurring on a respective branch of the power distribution system. The circuit breaker 114 protects the transformer 112 from faults not handled by any of the other circuit breakers and from faults on the main distribution bus 113 .
[0118] [0118]FIG. 1B schematically illustrates how the circuit breakers may be connected to the host computer 140 for monitoring the power distribution system. While only three of circuit breakers 114 , 116 and 118 are shown in FIG. 1B, other circuit breakers may be connected to the host computer 140 . The host computer 140 may comprise an ACCESS™ electrical distribution communication system, available from Siemens Energy and Automation, Inc., connected to an RS-485 port of the circuit breaker. A standard PC 115 , 117 , 119 connected to another communications port of the circuit breaker may also be used.
[0119] As shown, the host computer 140 is coupled to a display device 142 and a keyboard 144 . As set forth below, the host computer 140 may periodically poll each of the trip units, using a multi-drop line 141 such as an EIA-RS-485 line, to monitor the status of the power distribution system at the main bus and at each branch bus. In addition, the host computer 140 may issue commands to the various circuit breakers causing them to open or to change the levels at which pickup and trip events occur for certain parameters. As is further shown in FIG. 1B, each of the trip units 114 , 116 and 118 may be coupled to respective PCs 115 , 117 and 119 by a separate data communications port, such as an EIA-RS-232 communications port. The PC may be used to monitor the status and history of the circuit breaker it is connected to as well as issue commands to the circuit breaker causing it to open or to change the levels at which pickup and trip events occur for certain ones of the monitored parameters. These monitoring and control features are generally independent of those of the host computer 140 .
[0120] [0120]FIG. 2A is a block/schematic diagram of the trip unit portion of an exemplary circuit breaker 116 . The circuit breaker is assumed to be the unit 116 which isolates its branch line from the main bus 113 as shown in FIG. 1A. The circuit breaker includes the Protective microprocessor 214 for implementing the overcurrent protection functions of the circuit breaker and the Energy Information/Communications microprocessor 222 for implementing data communications features and monitors certain parameters and conditions and for providing display and input control functions. The Protective microprocessor 214 includes an 68HC11 microcontroller (available from Motorola), that is connected to a Programmable Read Only Memory (PROM) 216 . The PROM 216 stores program and fixed-value data.
[0121] Electrical current flowing through the three-phase lines 202 a , 202 b , and 202 c and the neutral line 202 n is sensed by four current transformers 204 a , 204 b , 204 c and 204 n . In the present embodiment, the current transformers 204 a , 204 b , 204 c and 204 n provide power for the circuit protection features. Current induced in the secondary winding of each current transformer is coupled to the
[0122] Energy Information Device(EID) 200 of circuit breaker 116 through current inputs 254 . These currents are then conditioned by signal conditioner 210 and provided to Protective microprocessor 214 .
[0123] The current transformers 204 supply operational power when the external power supply is not on. When the external power supply 226 is on, it supplies power to both the Protective microprocessor 214 and Energy Information/Communications microprocessor 222 . As shown in FIGS. 2A and 2B, the secondary windings of the transformers 204 a , 204 b , 204 c and 204 n are coupled to power supply 208 of the Protective microprocessor 214 . External control power required for Energy Information, communication and protective relaying functions is provided by external power supply 226 . Fail-safe protection is provided by overcurrent circuit 256 which is connected to trip circuit 212 . Trip circuit 212 is used to trip the contactor portion (not shown) of circuit breaker 116 under control of either override circuit 256 or Protective microprocessor 214 .
[0124] If during current monitoring, the Protective microprocessor 214 detects a large overcurrent condition indicative of a short circuit condition, or a smaller overcurrent condition persisting for longer than a predefined time interval, the Protective microprocessor 214 activates the trip circuit 212 , which activates trip solenoid 302 of FIG. 3 to break the connection between the branch lines 202 a , 202 b and 202 c and the main bus 113 .
[0125] Referring to FIG. 4, a front panel 400 of EID 200 has a keypad 244 for setting the pickup and trip levels used for primary overcurrent protection through a menu system (shown in Table V below). As set forth above, a pickup level is an overcurrent condition which may cause the trip unit to trip the circuit breaker, either after a delay (depending on the level) or instantaneously for relatively large overcurrent conditions. The configuration of the keypad 244 is described below with reference to FIG. 4.
[0126] As shown in FIG. 2C, a Real-Time-Clock (RTC) 234 is used as a time stamp for Energy Information/Communications microprocessor 222 and for keeping time within the energy information system. In the present embodiment, RTC 234 is a DS1283S available from Dallas Semiconductor Corp.
[0127] Referring to FIG. 4, the Energy Information/Communications microprocessor 222 is coupled to the front panel 400 of the EID 200 . The Energy Information/Communications microprocessor 222 indicates on the front panel 400 the event type, which caused the trip, by illuminating the appropriate LED display.
[0128] In the present embodiment, the Energy Information/Communications microprocessor 222 can activate three light emitting diodes 402 , 404 , 422 (LEDs) on front panel 400 . LED 402 is activated when a trip event occurs and LED 404 is activated when an alarm condition occurs. Trip events and alarm conditions are outlined below. The status of the current, voltage and frequency is monitored by the EID. As described below, various results of this monitoring are available for display within the display area 406 on the front panel 400 .
[0129] The Computer Operating Properly (COP) watchdog timer (not shown) continually monitors the status of the Protective microprocessor 214 . The exemplary watchdog timer must be written to by the Protective microprocessor 214 at regular intervals. If it fails to be written to within the expected time interval, code is invoked that:1) turns off the Protective System Check LED; (2) turns on the Protective microprocessor's Alarm line to indicate a system failure has occurred; (3) continues to provide a simplified type of over current protection such that if the instantaneous peak value of any phase current exceeds 130% of nominal, the breaker is tripped.
[0130] The Protective System Check LED 240 , activated by the Protective microprocessor 214 , and the Metering System Check LED 422 , activated by the Energy Information/Communications microprocessor 222 , provide “heartbeat” signals which provide a visual indication of the health of the respective microprocessors. In the exemplary embodiment, these LEDs flash when the respective microprocessors are operating normally.
[0131] In the present embodiment, the display area 406 is a liquid crystal display (LCD) which may display power related signals, histograms and alphanumerics representing user selected information on the status of the circuit breaker 116 . The display area 406 is a 128 by 128 monochrome pixel display. Of course, other sizes may be used as well as the use of color and the like. Further, the display area 406 may also be electrofluorescent or any other suitable display type. As shown in FIGS. 5A to 5 D, the types of signals 502 , 504 may be voltage and/or current for any or all phases of the power system. Histograms 506 , 508 may also be displayed to present information such as frequency harmonics, phase balance, pickups and delays, and other information. The alphanumerics display may provide an indication of current draw, phase voltage, phase angle, power factor, power consumption and other information.
[0132] The signals and histograms may be separately or commonly displayed in any combination as selected by the user. Information to be displayed is selected using a menu system available to the user by the display area 406 . Selections are made using the keypad 244 . The menu system may also provide for housekeeping items such as contrast adjustment for the LCD display. This is accomplished by having the appropriate menu appear on the screen and using the Up or Down keys to adjust the contrast. It has been found that adjustable contrast in an electronic trip unit is a desirable feature due to the variety of lighting environments in which circuit breakers are installed. The details of the menu system are described below with reference to Table V.
[0133] Referring to FIG. 2A, The Energy Information/Communications microprocessor 222 and Protective microprocessor 214 are interconnected by data path 258 in a master-slave relationship with Protective microprocessor 214 acting as the master. Communications between microprocessors 214 and 222 are based on a fixed length messages of 32 bytes each using an interrupt scheme initiated by Energy Information/Communications microprocessor 222 . Information, such as an indication that a long-time pickup event has occurred or that a trip event has occurred, are sent from Protective microprocessor 214 to Energy Information/Communications microprocessor 222 for display on the display 240 and/or communication to an external system, such as host computer 140 (FIG. 1B).
[0134] Referring again to FIG. 4, keypad 244 includes switches 408 , 410 , 412 and 414 for setting the various set points such as for instantaneous trip and display modes of the breaker 116 through the menu system displayed in display area 406 . For example, current is specified as a multiple of the rated current of the current sensors 204 (FIG. 2A). In the present embodiment, the current may be set to between twice and fifteen times the rated current of the sensor. When a Menu screen is displayed. The Up switch 408 moves the display cursor (not shown) upward in the menu list. The Down switch 410 moves the display cursor downward in the menu list. The Enter switch 412 selects the highlighted menu item and takes the user to that next lower level in the menu hierarchy. The Escape switch 414 moves the user up to the next higher level in the menu hierarchy.
[0135] When a Setting screen is displayed, the UP switch 408 increases the setting level. The Down switch 410 decreases the setting level. The Enter switch 412 moves to the next setting displayed on the screen (if more than one setting is displayed). The action of the Escape switch 414 depends on whether the user has changed a setting while a Setting screen is displayed. If no setting is changed, pressing Escape moves the user up to the next higher level in the menu hierarchy. If a setting is changed, pressing Escape causes a screen to be displayed that instructs the user to press Enter to accept and implement the change or press Escape to the reject change. When one or the other of these switches is pressed, the user is then moved up to the next higher level in the menu hierarchy. The ground fault trip parameters are also selected using the menu system. In the present embodiment, the ground-fault pickup may be set to no less than 20% and no more than 100% of the rated current of the breaker. The actual setting range allowed varies with the current rating of the specific breaker. The time delay before trip can be set to between 0.1 seconds and 0.5 seconds.
[0136] In addition to the display area 406 , switches 408 , 410 , 412 , 414 , the front panel 400 includes a connector 416 which may be used by the Energy Information/Communications microprocessor 222 to implement data communications with the PC using a EIA-RS232 communications protocol, and a connector 418 as a maintenance and test point to diagnose internal conditions of the EID 200 . Referring to FIG. 9B, a rear connector 702 couples the EID 200 to the circuit breaker 116 using connector 704 which in turn uses a connector (not shown) to connect the Energy Information/Communications microprocessor 222 to the host computer 140 to implement data communications using a EIA-RS485 communications protocol.
[0137] Referring again to FIG. 2A, the Energy Information/ Communications microprocessor 222 includes a 68HC16Z1 microcontroller available from Motorola, Inc. and a memory. This memory includes an external programmable read-only memory (PROM) 238 , which is used to store the program instructions and a random access memory (RAM) 236 which are external to the microcontroller. In the present embodiment, the PROM 238 is a pair of 27C010 integrated circuits and the RAM 236 is a pair of 62256 integrated circuits.
[0138] The Energy Information/Communications microprocessor 222 possesses both communications and monitoring capability and features. In addition to monitoring the current flowing through the lines, the Energy Information/Communications microprocessor 222 obtains the current and voltage of the three phase lines to monitor demand, power, energy and imbalances among the three phases. Voltage on one phase is used to obtain frequency information.
[0139] Data on the current and voltage flowing through the lines 202 a , 202 b , 202 c and 202 n is collected by an analog-to-digital converter (ADC) 232 which is coupled to the current sensors 204 . In addition, the ADC 232 is coupled through signal conditioner 230 to a potential transformer 206 which provides a measure of the voltage at each of the three phases. Signal conditioner 230 biases the voltage from transformers 206 and the current from transformers 204 above ground by an amount sufficient to result in a full-wave biased voltage. ADC 232 comprises a pair of ADC12048 12-bit ADCs manufactured by National Semiconductor and are coupled in parallel to Energy Information/Communications microprocessor 222 using bi-directional octal buffers (not shown). ADC 232 provides instantaneous samples of the current signals and voltage signals. The microcomputer 222 controls the ADC 232 to determine which sample to provide at any given time. Of course, it is believed that sigma-delta converters may also be used, as has been known since at least about the mid-1980's.
[0140] As set forth above, the Energy Information/Communications microprocessor 222 has two substantially independent communication ports. One port is a dedicated EIA-RS-485 communications port 246 that is coupled to the host computer 140 , and the other is an EIA RS-232 port 248 through which the Energy Information/Communications microprocessor 222 may be coupled to PC 117 . Both ports 246 and 248 include conventional opto-isolators to prevent any electrical connection between the Energy Information/Communications microprocessor 222 and the host computer 140 or the PC 117 . The Protective microprocessor 214 is also configured with an output line to the trip circuit 212 . This allows Protective microprocessor 214 to trip the circuit breaker 116 .
[0141] [0141]FIGS. 2B, 2C and 2 D provide a more detailed view of the interconnection of elements described above with respect to FIG. 2A. FIG. 2B shows the details of the protective board 298 . FIG. 2C shows the details of the metering board 299 . FIG. 2D shows the details of the interconnection between protective board 298 , metering board 299 and certain other components of circuit breaker 116 .
[0142] Referring to FIG. 2B, Protective microprocessor 214 uses an eight-bit data bus and sixteen-bit address bus 272 . The eight-bit data bus 270 and sixteen-bit address bus 272 are connected to PROM 216 Protective microprocessor 214 accesses PROM 216 using select line 274 . In the present embodiment, rating plug 218 uses four bits of the eight-bit data bus. The data from the rating plug 218 is accessed by Protective microprocessor 214 using select line 276 . The select lines 274 and 276 are controlled by Protective microprocessor 214 .
[0143] The current signals I A , I B , I C , and I N from transformers 204 are provided through connector 702 A (part of connector 702 mentioned above) to signal conditioner 210 , Protective microprocessor power supply 208 , and Energy Information/Communications board 299 . The conditioned current signals (I A ′, I B ′, I C ′, and I N ′), are provided to override circuit 256 . The power supply generates voltage from the current signals I A , I B , I C , and I N and supplies this voltage to trip circuit 212 . Trip circuit 212 is also provided with override trip signal 284 from override circuit 256 and microprocessor trip signal 286 from Protective microprocessor 212 . These signals are used to activate the trip solenoid (not shown). Override circuit 256 converts the current signals (I A ′, I B ′, I C ′, and I N ′) from differential signals to single ended signals and produces a differential current sum signal I S ′. These signals are provided to filter 282 which low pass filters the current signals to remove high frequency noise. The filtered current signals I A ″, I B ″, I C ″, I N ″, and I S ″ are then provided to Protective microprocessor 212 .
[0144] Referring now to FIGS. 24A and 24B the details of the interconnection of elements of the protective board 298 are explained. Referring to FIG. 24A, the IA+ signal is provided to one end of capacitor 2602 , the anode of diode 2606 , and the cathode of diode 2604 . The IA− signal is provided to the other end of capacitor 2602 and one end of resistor 2608 . The other end of resistor 2608 is connected to the cathode of diode 2610 and the anode of diode 2612 . The cathode of diode 2606 is connected to the cathode of diode 2612 the REF input of circuits 2624 , 2626 , and 2628 , and the anode of diode 2618 and the source of transistor 2620 . The anode of diode 2604 is connected to one end of the resistor 2614 and the IA+ input of circuit 2622 . The anode of diode 2610 is connected to one end of resistor 2616 and the IA− input of circuit 2622 . The other end of resistors 2614 and 2616 are connected to ground.
[0145] Circuits 2624 , 2626 and 2628 are identical to the circuits described above. Therefore, a detailed explanation of these circuits is not provided for simplicity. Circuit 2624 interfaces to the phase B current source, circuit 2626 interfaces to the phase C current source and circuit 2628 interfaces to the neutral current source respectively. Inputs IA+ and IA−, IB+ and IB−, IC+ and IC−, and IN+ and IN− are provided from connector 702 and are also connected to respective pins of connector 295 B. Similar to the inputs IA+ and IA− to circuit 2622 described above, the-outputs of circuits of 2624 , 2626 , and 2628 are connected to the IB+, IB−, IC+, IC−, IN+ and IN− inputs of circuit 2622 , respectively.
[0146] The VOR input of circuit 2622 is connected to one end of resistor 2694 and one end of resistor 2696 . The other end of resistor 2694 is connected to the +5 volts supply (not shown) and the second end of resistor 2696 is connected to ground. The gate of transistor 2620 is connected to one end of resistor 2630 , one end of capacitor 2632 , the cathode of zener diode 2634 , the anode of zener diode 2636 , and the FG input of circuit 2622 . The drain of transistor 2620 is tied to the other end of resistor 2630 , the other end of capacitor 2632 , the anode of diode 2634 and ground. The cathode of diode 2618 is connected to the cathode of zener diode 2636 , the positive input of capacitor 2638 , one end of resistor 2644 , the collector of transistor 2640 , the cathode of diode 2668 , and pins 9 and 5 of connector 702 (shown in FIG. 9B). The emitter of transistor 2640 is connected to the BJT input of circuit 2622 . The base of transistor 2640 is connected to the cathode of diode 2642 . The anode of diode 2642 is connected to the second end of resistor 2644 and the anode of diode pair 2648 . One cathode of diode pair 2648 is connected to the anode of diode 2672 , the cathode of diode 2674 , the anode of SCR 2662 , one end of capacitor 2603 , and one end of switch S 1 2664 . The second cathode of diode pair 2648 is connected to the anode of diode 2668 , the cathode of diode 2672 , one end of MOV 2676 , the anode of SCR 2656 , one end of capacitor 2601 , and pin 13 of connector 702 . The UT output of circuit 2622 is connected to one end of resistor 2650 . The second end of resistor 2650 is connected to one end of resistor 2652 , one end of capacitor 2654 , and the gate of SCR 2656 . The SG output of circuit 2622 is connected to the cathode of zener diode 2625 , one input of OR gate 2686 , and one end of resistor 2678 . The RST output of circuit 2622 is connected to the cathode of diode 2627 and the reset input of microprocessor 214 . The anode of diode 2627 is connected to the second input of OR gate 2686 , one end of resistor 2680 , one end of resistor 2670 , and the PA 7 input of microprocessor 214 . The second end of resistor 2670 is connected to one end of resistor 2658 , one end of capacitor 2660 , and the gate of SCR 2662 . The cathode of SCR 2656 is connected to the cathode of SCR 2662 , the second end of resistor 2652 , the second end of capacitor 2654 , the second end of resistor 2658 , the second end of capacitor 2601 , the second end of capacitor 2660 , the second end capacitor 2603 , the second end and case of switch 2664 , and ground. The second end of zener diode 2625 is connected to ground. The second end of resistor 2678 is connected to one anode of diode pair 2682 . The second end of resistor 2680 is connected to the second anode input of diode pair 2682 . The cathode of diode pair 2682 is connected to one end of resistor 2684 , and pin 1 of connector 296 . The other end of resistor 2684 is connected to ground. The anode of diode 2674 is connected to the second end of MOV 2676 and pin 17 of connector 702 . The output of OR gate 2686 is connected to one end of resistor 2688 . The second end of resistor 2688 is connected to one end of capacitor 2690 and pin 1 of connector 702 . The second end of capacitor 2690 is connected to ground. The second end of capacitor 2638 is connected to ground. The GS output of circuit 2622 is connected to one end of resistor 2692 and the PG 0 output of microprocessor 214 . The second end of resistor 2692 is connected to ground.
[0147] The IA output of circuit 2622 is connected to one end of filter 2629 . The second end of filter 2629 is connected to the AN 0 input of microprocessor 214 . The IB output of circuit 2622 is connected to one end of filter 2631 . The second end of filter 2631 is connected to the AN 1 input of microprocessor 214 . The IC output of circuit 2622 is connected to one end of filter 2633 . The second end of filter 2633 is connected to the AN 2 input of microprocessor 214 . The IN output of circuit 2622 is connected to one end of filter 2635 . The second end of filter 2635 is connected to the AN 3 input of microprocessor 214 . The ISUM+ output of circuit 2622 is connected to one end of filter 2639 . The second end of filter 2639 is connected to the AN 6 input of microprocessor 214 . The ISUM− output of circuit 2622 is connected to one end of filter 2637 . The other end of filter 2637 is connected to the AN 7 input of microprocessor 214 . The AN 4 input of microprocessor 214 is connected to pin 21 of connector 296 . The AN 5 input of microprocessor 214 is connected to pin 19 of connector 296 . Pin 19 of connector 702 is connected to one end of resistor 2702 and one end of resistor 2704 . A second end of resistor 2702 is connected to a 10 volt power source (not shown). Pin 14 of connector 702 is connected to the anode of zener diode 2706 , and to ground. The cathode of zener diode 2706 is connected to the second end of resistor 2704 and the PA 0 input of microprocessor 214 . The VRH input of microprocessor 214 is connected to the first end of resistor 2710 , the first end of resistor 2708 , and the first end of capacitor 2712 . The second end of resistor 2708 is connected to the digital voltage supply. The second end of capacitor 2712 is connected to second end of resistor 2710 and to ground. Pin 28 of connector 702 is connected to one end of resistor 2714 and pin 10 of connector 295 . The second end of resistor 2714 is connected to the YA input of buffer 2720 . Pin 35 of connector 702 is connected to one end of resistor 2716 and pin 20 of connector 295 . The second end of resistor 2716 is connected to the YB input of buffer 2720 . Pin 36 of connector 702 is connected to one end of resistor 2717 and pin 18 of connector 295 . The second end of resistor 2717 is connected to the YC input of buffer 2720 . Pin 4 of connector 702 is connected to one end of resistor 2718 . The second end of resistor 2718 is connected to the YD input of buffer 2720 . Pin 32 of connector 702 is connected to one end of resistor 2722 and pin 12 of connector 295 . The second end of resistor 2722 is connector A input of buffer 2730 . Pin 30 of connector 702 is connected to one end of resistor 2724 and pin 14 of connector 295 . The second end of resistor 2724 is connected to the B input of Buffer 2730 . Pin 31 of connector 702 is connected to one end of resistor 2726 and pin 18 of connector 295 . The second end of resistor 2726 is connected to the C input of buffer 2730 . The OE input of buffers 2720 and 2730 are connected to ground. The A, B, C, D outputs of buffer 2720 are connected to the TXD, PA 6 , PA 5 and PA 4 inputs of microprocessor 214 , respectively. The YA, YB, YC, and YD outputs of buffer 2720 are connected to the RXD, PA 3 , PA 2 and PA 1 inputs of microprocessor 214 respectively.
[0148] The A 0 -A 15 outputs of microprocessor 214 are connected to PROM 216 . The A 0 address line is further connected to the A input of selector 2768 and pin 11 of connector 2766 , the A 11 address line is further connected to the B input of selector 2768 and pin 9 of connector 2766 . The A 2 address line is further connected to pin 7 of connector 2766 . The A 8 , A 9 , A 10 and A 11 address lines are further connected to the A, B, C and G 2 B inputs of selector 2732 respectively. The A 13 address line is connected to an input of NAND gate 2734 . The A 12 , A 14 and A 15 address lines are further connected to respective inputs of OR gate 2738 . The output of NAND gate 2734 is connected to the G 2 A input of selector 2732 . The output of OR gate 2738 is connected to both inputs of NAND gate 2736 . The output of NAND gate 2736 is connected to the G 1 input of selector 2732 and the CE input of PROM 216 . The ECLK output of microprocessor 214 is connected to the OE input of PROM 216 and a second input of NAND gate 2734 . The D 0 -D 7 databus is output from microprocessor 214 and connected to the D 0 -D 7 input of PROM 216 , the B 1 -B 8 input of buffer 2764 , and pins 10 , 8 , 6 , 4 , 3 , 5 , 7 and 9 of connector 296 respectively. Data lines D 0 , D 1 , D 2 and D 3 are further connected to inputs YA, YB, YC and YD of buffer 2746 respectively. The Y 1 output of selector 2732 is connected to OE input of buffer 2746 and pin 16 of connector 296 . The Y 2 , Y 3 and Y 4 outputs of selector 2732 are connected to pins 18 , 20 , and 22 of connector 296 , respectively. The Y 5 output of selector 2732 is connected to both inputs of NAND gate 2740 , the G input of selector 2768 and pin 3 of connector 2766 . The output of NAND gate 2740 is connected to an input of OR gate 2742 . The second input of OR gate 2742 is connected to the PG 5 output of microprocessor 214 and pin 18 of connector 2766 . The output of OR gate 2742 is connected to both inputs of NAND gate 2744 . The output of NAND gate 2744 is connected to the OE input of buffer 2764 . The RAN output of microprocessor 214 is connected to the DIR input of buffer 2764 and to the D input of buffer 2770 .
[0149] The A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 and A 8 outputs of buffer 2764 are connected to pins 19 , 17 , 15 , 13 , 2 , 4 , 6 and 8 , respectively of connector 2766 . The MODB output of microprocessor 214 is connected to pin 5 of connector 2766 . The SS output of microprocessor 214 is connected to pin 20 of connector 295 . The SCK output (SCLK signal) from microprocessor 214 is connected to pin 24 of connector 295 A. The MOSI output of microprocessor 214 is connected to one end of resistor 2781 . The second end of resistor 2481 is connected to pin 16 of connector 295 A. The MISO output of microprocessor 214 is connected to one end of resistor 2783 . The second end of resistor 2783 is connected to pin 18 of connector 295 A. The PG 1 signal is connected between microprocessor 214 and the COOL input of circuit 2622 . The PG 2 output of microprocessor 214 is connected to pin 11 of connector 296 . The PG 3 output of microprocessor 214 is connected to pin 13 of connector 296 . The PG 4 signal is connected between microprocessor 214 and pin 15 of connector 296 . The IRQ signal is connected between the microprocessor 214 and pin 14 of connector 295 A. The XTAL input of microprocessor 214 is connected to a first end of resistor 2774 , a first end of crystal 2772 , and a first end of capacitor 2778 . The EXTAL input of microprocessor 214 is connected to the second end of resistor 2774 , the second end of crystal 2772 , and the first end of capacitor 2776 . The second end of capacitor 2776 is connected to the second end of the capacitor 2778 and to ground. The VRH input of microprocessor 214 is connected to the first end of capacitor 2780 , a first end of resistor 2782 and a first end of resistor 2784 . The second end of the resistor 2784 is connected to the logic voltage supply. The second end of capacitor 2780 and the second end of the resistor 2782 are connected to ground.
[0150] The PG 7 input of microprocessor 214 is connected to the first end of resistor 2786 and a normally open contact of switch 2788 . The second end of resistor 2786 is connected to ground. The common pole of switch 2788 is connected to the logic supply. The Y 0 , Y 1 and Y 2 outputs of selector 2768 are connected to the C, B and A inputs, respectively, of buffer 2770 . The OE input of buffer 2770 is connected to ground. The YA, YB, YC and YD outputs of buffer 2770 are connected to pins 16 , 14 , 12 and 10 , respectively, of connector 2776 . The A output of buffer 2746 is connected to a first end of resistor 2754 and a first end of resistor 2762 . The second end of resistor 2762 is connected to pin 3 of connector 218 . The B output of buffer 2746 is connected to a first input of resistor 2752 and a first end of resistor 2760 . The second end of resistor 2760 is connected to pin 4 of connector 218 . The C output of buffer 2746 is connected to a first end of resistor 2750 and a first end of resistor 2758 . The second end of resistor 2758 is connected to pin 5 of connector 218 . The D output of buffer 2746 is connected to a first end of resistor 2748 and a first end of resistor 2756 . The second end of resistor 2756 is connected to pin 6 of connector 218 . The second end of resistors 2748 , 2750 , 2752 and 2754 are connected to ground.
[0151] As mentioned above, the Protective microprocessor 212 communicates with Energy Information/Communications microprocessor 222 . The communication interface is shown in FIGS. 2B and 2C. Protective microprocessor 212 is connected with Energy Information/Communications microprocessor 222 using SPI data line 258 and SPI interrupt line 259 . The transfer of data between Protective microprocessor 212 and Energy Information/Communications microprocessor 222 is further described below.
[0152] [0152]FIG. 2D shows the interconnection of protective board 298 and Energy Information board 299 . FIG. 2D Protective board 298 and metering board 299 are interconnected with wire bundles 295 A, 295 B and 296 through connectors 295 C/ 295 D, 295 E/ 295 F, and 296 A/ 296 B, respectively. In the present embodiment, wire bundles 295 and 296 may be ribbon cable or discrete wires, for example. The protective board 298 is also connected to the rating plug 218 and the circuit breaker 116 using connectors 291 , 292 and 293 , respectively. The metering board 299 is connected to test connector 220 , LCD 240 , keypad 244 , and serial port 248 using connectors 291 , 292 , 293 and 294 , respectively.
[0153] Referring now to FIGS. 23 A- 23 I, a detailed schematic diagram of the Energy Information board 299 is shown. Elements identical to those in FIG. 2C use identical reference numbers. Information Energy/Communications microprocessor 222 is connected to PROM 238 A, 238 B and to RAM 236 A 236 B by the address bus 223 and address bits A 1 -A 17 and A 1 -A 15 , respectively. Information Energy/Communications microprocessor 222 is connected to RTC 234 through address bits A 0 -A 5 via address bus 223 . Address bus 223 is also connected to UART 248 A by address bits A 0 -A 2 , to OR gate 2302 with address bit A 1 , and OR gate 2304 with address bit A 2 . R/W signal 229 is connected between Information Energy/Communication microprocessor 222 , RTC 234 , RAM 236 A, 236 B, the input of inverter 2306 , one input of NOR gate 2308 , one input of OR gate 2312 , one input of UART 248 A, one input (DIR) of buffer 2316 , and one input (DIR) of buffer 2318 . Chip select 2324 (CS 9 ) is connected from Energy Information/Communication microprocessor 222 to the inputs of NAND gate 2320 . The output of NAND gate 2320 is connected to one input of NAND gate 2322 . The other input of NAND gate 2322 is connected to the reset input of Energy Information/Communication microprocessor 222 , a pin output of diagnostic connector 2326 , the output of reset circuit 2328 , one end of resistor 2330 , and the inputs of NAND gate 2332 . The output of NAND gate 2322 is connected to the chip enable of RTC 234 . The CS 10 output of Energy Information/Communication microprocessor 222 is connected to the output enable input of RTC 234 . One end of crystal 2334 is connected to an input (X 1 ) of RTC 234 and the other end of crystal 2334 is connected to another input (X 2 ) of RTC 234 . In the present embodiment, crystal 2334 is a 32.768 KHz crystal. Databus 225 is connected between Energy Information/Communication microprocessor 222 PROM 238 A, 238 B, RAM 236 A, 236 B, RTC 234 , UART 248 A, Buffer 2316 , Buffer 2318 , and LCD interface 240 A. In the present embodiment, databus 225 is a 16-byte bus with bits D 0 -D 7 connected to PROM 238 A, RAM 236 A, and Buffer 2318 , and bits D 8 -D 15 connected to PROM 238 B, RAM 236 B, RTC 234 , UART 248 A, LCD interface 240 A, and Buffer 2316 . In the present embodiment, LCD interface 240 A is an 8-bit latch such as a 74HC373.
[0154] The input of reset circuit 2328 is connected to the other end of resistor 2330 and the logic voltage source (not shown). It is understood that logic and analog voltages are supplied to various circuits of Energy Information board 299 but are not shown for simplicity. CS boot signal 2391 is output from Energy Information/Communication microprocessor 222 and connected to an input (CE) of PROM 238 A, 238 B. CS 2 signal 2336 is connected from an output of Energy Information/Communication microprocessor 222 to an input (CE) of RAM 236 B.
[0155] CS 3 signal 2338 is connected between Energy Information/Communication microprocessor 222 and an input (CE) of RAM 236 A. The LCD enable signal (LCD_ENABLE) is output (CS 5 ) from Energy Information/Communication microprocessor 222 to the input of inverter 2340 . The output of inverter 2340 is connected to pin of LCD connector 292 . The CLKOUT signal is output (CLKOUT) from Energy Information/Communication microprocessor 222 to an input (CLK) of Counter 2342 . The output of NAND gate 2332 is connected to an input (CLK) of Counter 2342 and an input (MR) of UART 248 A. An output (Q 2 ) of counter 2342 is connected to an input (XIN) of UART 248 A. Another output (Q 1 ) of counter 2342 is connected to an input (CLK) of ADC 232 A and to an input (CLK) of ADC 232 B. LCD_CS signal 2344 is connected between an output (CS 4 ) of Energy Information/Communication microprocessor 222 and the LCD connector 292 .
[0156] One end of crystal 2346 is connected to one end of capacitor 2348 , a first end of resistor 2354 and an input (EXTAL) of Energy Information/Communication microprocessor 222 . The other end of crystal 2346 is connected to one end of capacitor 2350 and one end of resistor 2352 . The other end of resistor 2352 is connected to the second end of resistor 2354 and to an input (XTAL) of Energy Information/Communication microprocessor 222 . The second end of capacitor 2348 is connected to the second end of capacitor 2350 and to ground. One end of capacitor 2356 is connected to an input (XFC) of Energy Information/Communication microprocessor 222 . The other end of capacitor 2356 is connected to one end of capacitor 2358 , one end of capacitor 2360 , and to the digital voltage supply. The other end of capacitor 2358 and the other end of capacitor 2360 are connected to ground. One end of resistor 2362 is connected to an input (MODCLK) of Energy Information/Communication microprocessor 222 , and the other end of resistor 2362 is connected to the digital voltage supply. UART select (UART_CS) 227 A is output (CS 8 ) from Energy Information/Communication microprocessor 222 and connected to an input (CS 2 ) of UART 248 A.
[0157] An interrupt (INTRPT) of UART 248 A is connected to an input of inverter 2390 and the output of inverter 2390 is connected to an interrupt input (IRQ 4 ) of Energy Information/Communication microprocessor 222 . Contrast control signal 227 D is output (CS 7 ) from Energy Information/Communication microprocessor 222 to both inputs of NAND gate 2392 . The output of NAND gate 2392 is connected to a latch enable input of LCD interface 240 A. Each of the 8 latched outputs (Q 0 :Q 7 ) from LCD interface 240 A are respectively connected to one end of resistors 2394 A- 23941 . The second ends of resistors 2394 A- 23941 are connected to one another and to one end of resistor 2396 and to an inverting input of OPAMP 2398 . The non-inverting input of OPAMP 2398 is connected to ground and the output of OPAMP 2398 is connected to the other end of resistor 2396 and to pins of the LCD connector 292 . A first pin of diagnostic connector 2326 is connected to one end of resistor 2368 and an input (BERR) of Energy Information/Communication microprocessor 222 . The other end of resistor 2368 is connected to the digital voltage supply. A second pin of connector 2326 is connected to an input (DS) of Energy Information/Communication microprocessor 222 . A third pin of connector 2326 is connected to one end of resistor 2366 and an input (BK/DSCLK) of Energy Information/Communication microprocessor 222 . The other end of resistor 2366 is connected to the digital voltage supply. Two additional pins of connector 2326 are connected to digital ground. One additional pin of connector 2326 is connected to the digital voltage supply. Three additional pins of connector 2326 are connected to respective inputs (IP 0 /DS 0 , IP 1 /DS 1 , FRZ/QUOT) of Energy Information/Communication microprocessor 222 . The LCD—RST signal is connected between the LCD connector 292 and an output (OC2) of Energy Information/Communication microprocessor 222 . The alarm output (OC3) of Energy Information/Communication microprocessor 222 is connected an input of NAND gate 2402 . The other input of NAND gate 2402 is connected to one end of capacitor 2404 and one end of resistor 2406 . The other end of capacitor 2404 is connected to ground. The other end of resistor 2406 is connected to the output of NAND gate 2402 and one end of resistor 2408 . The other end of resistor 2408 is connected to alarm LED 404 and the other end of alarm LED 404 is connected to the logic voltage supply.
[0158] The TRPMB signal (PWMB) from Energy Information/Communication microprocessor 222 is connected to one end of resistor 2410 . The second end of resistor 2410 is connected to the base of transistor 2412 . The emitter of transmitter 2412 is connected to ground, and the collector is connected to one end of resistor 2414 . The second end of resistor 2414 is connected to trip LED 402 and the other end of trip LED 402 is connected to the logic voltage supply. One end of resistor 2416 is connected to watchdog signal from the microprocessor 214 (PG 6 ) on the protective circuit board via pin 12 of connector 296 . The other end of resistor 2416 is connected to the base of transistor 2418 .
[0159] The emitter of transistor 2418 is connected to ground and the collector is connected to one end of resistor 2420 . The other end of resistor 2420 is connected to protective LED 420 on front panel 400 . METR_CHK signal is output (OC4) from Energy Information/Communication microprocessor 222 to one end of resistor 2364 . The other end of resistor 2364 is connected to one end of meter LED 422 and the other end of meter LED 422 is connected to the logic voltage supply. One end of switch 408 is connected to one end of resistor 2374 , one end of capacitor 2376 , and the UP signal input (ADA 0 ) to Energy Information/Communication microprocessor 222 . One end of switch 410 is connected to one end of resistor 2380 , one end of capacitor 2378 , and the DOWN signal input (ADA 1 ) of Energy Information/Communication microprocessor 222 . One end of switch 412 is connected to one end of resistor 2382 , one end of capacitor 2386 , and the RETURN input (ADA 2 ) of Energy
[0160] Information/Communication microprocessor 222 . One end of switch 414 is connected to resistor 2384 , one end of capacitor 2388 , and the ESC input (ADA 3 ) of Energy Information/Communication microprocessor 222 . The other end of switches 408 , 410 , 412 , 414 , and the second end of capacitors 2376 , 2378 , 2386 and 2388 are connected to ground. The second end of resistors 2374 , 2380 , 2382 , 2384 are connected to the digital voltage supply.
[0161] The ADC_CS signal is connected between Energy Information/Communication microprocessor 222 (CS 6 ) and an input of OR gate 2302 , an input of OR gate 2304 , enable input (OE) of buffer 2316 , and enable input (OE) of buffer 2318 . The output of OR gate 2304 is connected to an input of OR gate 2308 , an input of OR gate 2310 , and a chip select input (CS) of ADC 232 A. The output of OR gate 2302 is connected to an input of OR gate 2312 , an input of OR gate 2314 , and a chip select input (CS) of ADC 232 B. An output of inverter 2306 is connected to the other input of OR gate 2310 , the other input of OR gate 2314 , and the RD input of UART 248 A. The output of OR GATE 2308 is connected to the WR input of ADC 234 A. The output of OR GATE 2310 is connected to the RD input of ADC 232 A. The output of OR GATE 2312 is connected to the WR input of ADC 232 B. The output of OR GATE 2314 is connected to the RD input of ADC 232 B. Bi-directional data inputs D 0 -D 7 of ADC 232 A are connected to the D 0 -D 7 bi-directional data inputs of ADC 232 B and the bidirectional data inputs (A 1 :A 8 ) of buffer 2318 . The D 8 -D 12 bidirectional data inputs of ADC 232 A are connected to the D 8 -D 12 bidirectional data inputs of ADC 232 B and to the A 1 -A 5 inputs of buffer 2316 . The SYNC output of ADC 232 A is connected to an input of OR gate 2309 . The SYNC output of ADC 232 B is connected to the other output of OR gate 2309 . The RDY output of ADC 232 A is connected to an input of OR gate 2311 . The RDY output of ADC 232 B is connected to the other input of OR gate 2311 . The output of OR gate 2309 is connected to the ADCDONE input (IC1) of Energy Information/Communication microprocessor 222 . The output of OR gate 2311 is connected to the ADCREADY input (IC2) of Energy Information/Communication microprocessor 222 .
[0162] The SOUT signal is connected between UART 248 A and one end of resistor 2333 . The other end of resistor 2333 is connected to the base of transistor 2331 . The emitter of transistor 2331 is connected to ground. The collector of transistor 2331 is connected to one end of resistor 2329 , and the other end of resistor 2329 is connected to the cathode of optoisolator 2335 . The anode of optoisolator 2335 is connected to the digital voltage supply. The base of optoisolator 2335 is connected to one end of resistor 2337 . The other end of resistor 2337 is connected to the emitter of optoisolator 2335 , the collector of transistor 2341 and an output pin of connector 2353 . The base of transistor 2341 is connected to the anode of diode 2343 and one end of resistor 2339 . The other end of resistor 2339 is connected to the collector of optoisolator 2335 , one end of resistor 2327 , and one end of resistor 2345 . The other end of resistor 2327 is connected to the collector of transistor 2349 and a pin of connector 2353 . The other end of resistor 2345 is connected to the base of transistor 2349 and the cathode of diode 2347 . The anode of diode 2347 is connected to the emitter of transistor 2349 , the emitter of transistor 2341 , the cathode of diode 2343 , and one end of the resistor 2351 . The other end of resistor 2351 is connected to a pin of connector 2353 . The SIN input of UART 24 A is connected to one end of resistor 2313 and a collector of optoisolator 2315 . The emitter of optoisolator 2315 is connected to ground. A second collector of optoisolator 2315 is connected to the other end of resistor 2313 and to the digital voltage supply. The cathode of optoisolator 2315 is connected to one end of resistor 2321 and a pin of connector 2353 . The other end of resistor 2321 is connected to the base of transistor 2317 , the collector of transistor 2319 and the anode of diode 2325 . The cathode of diode 2325 is connected to the emitter of transistor 2319 , one end of resistor 2323 , and a pin of connector 2353 . The base of transistor 2319 is connected to the other end of resistor 2323 and to the emitter of transistor 2317 . The RI input of UART 248 A is connected to the digital voltage supply and the CTS and DCD inputs of UART 248 A to connected ground.
[0163] The PF 3 signal of Energy Information/Communication microprocessor 222 is connected to one end of the resistor 2359 . The other end of resistor 2359 is connected to the DE input of UART 246 A. The TXD output of Energy Information/Communication microprocessor 222 is connected to one end of resistor 2357 , and the other end of resistor of 2357 is connected to the DI input of UART 246 A The RO output of UART 246 A is connected to one end of resistor of 2361 and the input of inverter 2363 . The other end of resistor 2361 is connected to the digital voltage supply. The output of inverter 2363 is connected to the RX input (RCD) of Energy Information/Communication microprocessor 222 . One end of resistor 2365 is connected to the IRO LED input of UART 246 A and the other end of resistor 2365 is connected to the IRODRV input of UART 246 A. One end of resistor 2367 is connected to the IDEDRV and IDEIN inputs of UART 246 A. The other end of resistor 2367 is connected to one end of resistor 2369 and to the IVCCB and IBCCA inputs of UART 246 A. The other end of resistor 2369 is connected to the IDIIN and IDIDRV inputs of UART 246 A. The A input of UART 246 A is connected to one end of temperature compensating resistor 2373 and one end of diode 2375 . The other end of diode 2375 is connected to ground and the other end of temperature compensating resistor 2373 is connected to a pin of connector 295 A. The B input of UART 246 A is connected to one end of temperature compensating resistor 2371 and one end of diode 2377 . The other end of 2377 is connected to ground and the other end of temperature compensating resistor 2371 is connected to a pin of connector 295 A.
[0164] The signals SCLK, MISO, MOSI, SS, and PUPIRQ (SCK, MISO, MOSI, PCS 0 /SS, PCS 1 ) of Energy Information/Communication microprocessor 222 are connected to the protective board via respective pins of connector 295 A. One end of resistor 2381 is connected to the SS input of Energy Information/Communication microprocessor 222 and the other end of resistor 2381 is connected to the digital voltage supply. The PF 1 input of Energy Information/Communication microprocessor 222 is connected to one end of resistor 2372 and a pin of LCD connector 292 . The PF 2 input of Energy Information/Communication microprocessor 222 is connected to one end of resistor 2370 and a pin of LCD connector 292 . The other end of resistor 2370 is connected to the other end of resistor 2372 and to the digital voltage supply. The IC3 (signal TRIP_CLK) input of Energy Information/Communication microprocessor 222 is connected to a pin of connector 296 . The IC4/OC5 input (signal VFREQ) of Energy Information/ Communication microprocessor 222 is connected to the output of inverter 1032 shown in FIG. 10.
Voltage and Current Sensing
[0165] The VIN input of temperature compensating circuit 2355 is connected to the analog voltage supply. The TEMP output of temperature compensating circuit 2355 is connected to the non-inverting input of comparator 2457 . The GND input of temperature compensating circuit 2355 is connected to ground. The COMP output of temperature compensating circuit 2355 is connected to one end of capacitor 2465 . The other end of capacitor 2465 is connected to the VOUT output of temperature compensating circuit 2355 , one end of capacitor 2463 , and the inverting input of comparator 2467 . The output of comparator 2457 is connected to one end of resistor 2459 . The other end of resistor 2459 is connected to the inverting input of comparator 2457 , one end of resistor 2461 and the CH 3 input of ADC 232 B. The other end of resistor 2461 is connected to ground. The output of comparator 2467 is connected to the base of transistor 2469 , the base of transistor 2473 , and one end of capacitor 2471 . The other end of capacitor 2471 is connected to the emitter of transistor 2469 , the emitter of transistor 2473 , the non inverting input of comparator 2467 , one end of resistor 2401 , one end of resistor 2441 , and the VREF inputs of circuits 2429 , 2431 , 2433 , 2435 , 2437 , and 2439 . The collector of transistor 2469 is connected to the positive analog voltage supply, and the collector of transistor 2473 is connected to the negative analog voltage supply. The other end of capacitor 2463 is connected to ground.
[0166] The circuitry of voltage offset circuits for phase A 2455 , phase B 2439 , and phase C 2437 is identical and for brevity will only be described with reference to the voltage offset circuit for phase A 2455 . In the phase A voltage offset circuit 2455 , the VREF signal is connected to one end of resistor 2401 . The second end of resistor 2401 is connected to one end of resistor 2403 and to an output VAO to the CH 0 input of ADC 232 B as the phase A voltage. Circuits 2439 and 2437 have corresponding outputs VB 0 and VC 0 which are connected to the CH 1 and CH 2 inputs of the ADC 232 B respectively. The VA input to circuit 2455 is received from a pin of connector 295 and is connected to one end of resistor 2415 and one end of capacitor 2419 . Circuits 2439 and 2437 have corresponding inputs VB and VC from connector 295 . The other end of capacitor 2419 is connected to ground. The other end of resistor 2415 is connected to one end of capacitor of 2417 , one end of resistor 2413 , and the non-inverting input of comparator 2409 . The inverting input of comparator 2409 is connected to one end of resistor 2411 , one end of capacitor 2405 , and one end of the resistor 2407 . The other ends of capacitor 2417 , resistor 2413 , and resistor 2411 are connected to ground. The output of comparator 2409 is connected to one end of resistor 2421 , the other end of resistor 2407 , the other end of capacitor 2405 , and the other end of resistor 2403 . The other end of resistor 2421 is connected to one end of resistor 2425 , one end of capacitor 2423 , and the inverting input of comparator 2427 . The non-inverting input of comparator 2427 is connected to ground. The other end of capacitor 2423 is connected to the other end of resistor 2425 and the output of comparator 2427 and one end of resistor 1038 shown in FIG. 10 (input 1002 of amplifier 1004 ).
[0167] The circuitry of current offset circuits for phase A 2429 , phase B 2431 , phase C 2433 , and neutral 2435 are identical and will be described below with reference to the current offset circuit for phase A as shown in FIG. 231, the M.IC+ signal is connected from pin on connector 295 to one end of resistor 2500 . Phase A, B, and neutral current offset circuits have corresponding signals M.IA+, M.IB+, and M.IN+ respectively. The other end of resistor 2500 is connected to one end of capacitor 2504 and one end of resistor 2506 . The P&M.IC− signal is connected from a pin on connector 295 to one end of resistor 2502 . Phase A, B, and neutral current offset circuits have corresponding signals P&M.IA−, P&M.IB−, and P&M.IN−, respectively, connected to pins on connector 295 . The other end of resistor 2502 is connected to the second end of capacitor 2504 and one end of resistor 2508 . The other end of resistor 2508 is connected to one end of resistor 2516 , and one end of resistor 2510 . The second end of resistor 2506 is connected to one end of resistor 2512 and one end of resistor 2518 . The other end of resistor 2516 is connected to one end of resistor 2520 and the inverting input of comparator 2522 . The other end of resistor 2518 is connected to one end of resistor 2514 and the non-inverting input of comparator 2522 . The second end of resistors 2510 , 2512 , and 2514 are connected to ground. The output of comparator 2522 is connected to the other end of resistor 2520 and one end of 2524 . The other end of resistor 2524 is connected to one end of resistor 2526 and to the CH 2 input of ADC 232 A as signal IC. Phase A, B, and neutral current offset circuits have corresponding signals IA, IB, and IN connected to inputs CH 0 , CH 1 , and CH 3 of ADC 232 A respectively. The second end of resistor 2526 is connected to the VREF source. Phase A, B, and neutral current offset circuits have corresponding connections to the VREF source.
[0168] The second end of resistor 2441 is connected to the VREF+ input of ADC 232 A and the VREF+ input of ADC 232 B, one end of capacitor 2443 and one end of capacitor 2445 . The other end of capacitors 2443 and 2445 are connected to ground.
[0169] Referring to FIG. 2C, current signals I A , I B , I C , and I N are provided from protective board 298 by wire bundle 295 to current offset amp 230 A. Voltage signals V A , V B , and V C are provided from circuit breaker 116 through connector 704 C to voltage offset amp 230 B. Offset generator 230 C generates a fixed offset voltage and provides this offset voltage to current offset amp 230 A and voltage offset amp 230 B to offset the current and voltage, respectively, such that the resulting signals are full wave signals offset above ground potential. This allows EID 200 to process full wave voltage and current signals rather than full wave rectified signals. The exemplary offset reference generator 230 C supplies a stable 4.096 V reference voltage. The offset amplified current signals are supplied to current ADC 232 A and the offset amplified voltage signals are supplied to voltage ADC 232 B. Phase A of the offset amplified voltage signal is also provided to zero-crossing frequency sensor 228 , which is shown in greater detail in FIG. 10.
[0170] [0170]FIG. 10 shows the circuit of the transition detector 228 . The offset amplified phase A voltage signal is provided at input 1002 of amplifier 1004 . The output of amplifier 1004 is coupled to resistor 1006 to provide current limiting. The other end of resistor 1006 is connected to the base of transistor 1008 and the cathode of diode 1010 . In the present embodiment, diode 1010 is a zener diode. The anode of diode 1010 is connected to analog signal ground reference 1012 . Diode 1010 clips the output signal of amplified 1004 to approximately the avalanche voltage of diode 1010 . The collector of transistor 1008 is connected to one end of resistor 1014 and the emitter of transistor 1020 . The other end of resistor 1014 is connected to +5 V analog supply 1036 . The emitter of transistor 1008 is connected to the collector of transistor 1016 and the emitter of transistor 1018 . The emitter of transistor 1016 is connected to the emitter of transistor 1024 and the −12 V supply 1034 . The base of transistor 1018 is connected to analog signal ground reference 1012 . The collector of transistor 1018 is connected to the base of transistor 1020 , the emitter of transistor 1026 and one end of resistor 1028 . The other end of resistor 1028 is connect to the +5 V analog supply 1036 . The base of transistor 1016 is connected to the base of transistor 1024 and the emitter of transistor 1022 . The base of transistor 1022 is connected to the collector of transistor 1024 and one end of resistor 1038 . The other end of resistor 1038 as well as the collector of transistor 1022 are connected to analog signal ground reference 1012 . The collector of transistor 1020 is connected to the collector of transistor 1026 , one end of resistor 1030 , and the input of inverter 1032 . The output of inverter 1032 provides signal VFREQ as an interrupt to the Energy Information/communication microprocessor 222 .
[0171] The voltage signal from voltage offset amp 230 B is further amplified by amplifier 1004 . The resultant signal is coupled to resistor 1006 to provide current limiting. Diode 1010 limits the output signal to less than or equal to the avalanche voltage, which in the exemplary embodiment is 4.7 V. The transistors 1008 , 1016 , 1018 , 1020 , 1022 , 1024 and 1026 and their associated biasing resistors 1014 , 1028 , 1030 and 1038 are arranged such that the voltage signal presented at the cathode of diode 1010 will be converted to a “1” to “0” transition when the voltage signal from voltage offset amp 230 B has a zero crossing. This “1” to “0” transition is inverted by inverter 1032 to a “0” to “1” transition which results in an interrupt to Energy Information/Communications microprocessor 222 for an input voltage transition or zero crossing.
[0172] Energy Information/Communications microprocessor 222 uses a 16-bit data bus 225 and a 19-bit address bus 223 to communicate with current ADC 232 A, voltage ADC 232 B, PROM 238 , RAM 236 , UART 248 A, RTC 234 and LCD interface 240 A. Energy Information/Communications microprocessor 222 also uses a combination of unique select lines 227 A, 227 B, 227 C as well as read/write (R/W) signal 229 to control data flow to and from these devices. Not all devices use the entire 16 bits of data bus 225 and all 19 bits of address bus 223 . For example, 17 bits of address bus 223 are connected to PROM 238 , and address bits A 1 -A 17 are connected to PROM 238 and 15 bits of address bus 223 are connected to RAM 236 .
[0173] To access the data stored in PROM 238 , Energy Information/Communications microprocessor 222 selects PROM 238 by invoking ROMSEL 227 C. When ROMSEL 227 C is set to a logic level of “0” (active low) the 16 bit data stored in PROM 238 corresponding to the address represented by A 1 -A 17 will be placed on data bus 225 by PROM 238 . RAM 236 is accessed in a similar manner with the following exceptions. Two select lines 227 B are used to select either or both a low byte of data or a high byte of data from RAM 236 . In addition, R/W signal 229 is appropriately set if data is to be written (R/W set to a logic “0”) or read (R/W set to a logic “1”) from RAM 236 . As above, as long as the appropriate select lines are active, data corresponding to address lines A 1 -A 15 will be read from or written to RAM 236 .
[0174] In the present embodiment, two National ADC 12048 twelve-bit AND converters (ADC) 232 A, 232 B are used. ADC 232 A samples current and ADC 232 B samples voltage. The ADC 232 A, 232 B provide 12-bits of resolution plus a sign bit and a 13-bit parallel output port. When used in the 13-bit mode, only a single read is required to retrieve the data from a conversion. As mentioned above, since data bus 225 is 10 bits wide, a single read returns all 13 bits of the voltage data and another read returns all 13 bits of the current data. ADC 232 A, and ADC 232 B each use 3 control lines, a chip select, an active low read enable and an active low write enable to read and write. A configuration register inside the AID (not shown) is written to set up which channel ( 0 - 7 ) will be converted. The addressing logic (not shown) is set up such that a single write is received by ADC 232 A, 232 B essentially simultaneously. On the other hand, each ADC 232 A, 232 B is read using individual commands and addressing to prevent bus contention problems which might corrupt the data.
[0175] In the present embodiment, chip select 6 of the Energy Information/Communications microprocessor maps ADC 232 A, 232 B into a 2K memory block starting at address 7E800 hex (see Table IX below). Chip Select 6 enables ADC 232 A, 232 B for reads and writes. Bits A 1 and A 2 of address bus 223 , in conjunction with R/W line 229 enable writes to both ADC 232 A and 232 B for address 7E800, reads of ADC 232 A for current samples at address 7E802, and reads of ADC 232 B for voltage samples at address 7E804. An and conversion is started by writing into the configuration register of ADC 232 A, 232 B a command indicating the start mode with the channel of interest selected. The next read of ADC 232 A, 232 B will start a conversion in the respective ADC. The RDY 237 and DONE 233 outputs from ADC 232 A, 232 B will be driven high while the conversion is in progress, then they will go low when the conversion is complete. The falling edge of the DONE 233 line will cause an interrupt to Energy Information/Communications microprocessor 222 . At this time the results of the conversion may be read from ADC 232 A, 232 B.
[0176] A reference voltage for ADC 232 A, 232 B is provided by offset reference generator 230 C and is set to 4.096 V in the present embodiment. This configures ADC 232 A, 232 B to accept signals ranging from 0 V to +4.096 V. This corresponds to approximately 1 mV per bit. The center point of the range which corresponds to a 0 output is 2.048 V so that ADC 232 A, 232 B operates in the positive domain. Therefore, the 13th bit (sign bit) is not used and the 12th bit represents the sign bit. In addition, ADC 232 A, 232 B are isolated from possible noise on data bus 225 by two bi-directional octal buffers 2316 and 2318 (shown in FIG. 23G). ADC 232 A, 232 B is also supplied with an ADC CLK signal 239 of approximately 8 Mhz from ADC CLK generator 232 C. This clock is derived from a 15.991 Mhz clock generated by Energy Information/Communications microprocessor 222 . As a result, a maximum conversion time of about 5.5 μs is obtained.
[0177] The Energy Information/Communications microprocessor 222 monitors line current and voltage for each of the branch lines 202 through the ADC 232 and, from these values calculates other values which indicate the status of the lines 202 . It also controls communication between the host computer 140 , PC 117 , keypad 244 and LCD 240 . The monitoring feature involves obtaining voltage and current samples from the branch lines 202 , calculating and storing various parameters derived from these samples which indicate certain events and, logging certain of these events as they occur. Table I lists the parameters which may be determined by the Energy Information/Communications microprocessor 222 .
TABLE I Parameter Parameter Phase A current Phase A voltage (to neutral) Phase B current Phase B voltage (to neutral) Phase C current Phase C voltage (to neutral) Average current (A, B & C) Average phase voltage Neutral current 1 Crest Factor (peak/RMS for Ground Fault current each phase) Present Current Demand Real power Maximum Current Demand Reactive power Line voltage A-B Apparent power Line voltage B-C Frequency Line voltage C-A Kilowatt hours forward Power factor (each phase and Avg.) Kilowatt hours reverse Avg. line-line voltage kVAR Avg. L-N voltage (each phase) Kilowatt demand Demand period time Harmonic analysis (THD, each phase & neutral)
[0178] For each parameter, the Energy Information/Communications microprocessor 222 records in a log the present value, as well as the maximum and minimum values, that have occurred since the last time the log was cleared. The monitored voltage and current values are RMS values generated from sample values taken, for example, over a one-second interval. The frequency is determined by measuring the time interval between zero-crossing points of the measured voltage signal for only one of the three phases, doubling the measured interval and inverting it to convert it into a frequency. Sixty-four (64) samples are taken each cycle with each phase being sampled over 6 cycles once per second resulting in 384 samples per second. The EID has a nominal frequency input range of about 40 Hz to 70 Hz. Frequency is not believed to be essential to measuring the various parameters. Without using the frequency of one phase, the accuracy of various measurements, such as power factor, may be slightly degraded. If a measured frequency is not available, then a user selected pre-programmed frequency of either 60 Hz (U.S.) or 50 Hz (European) is used.
[0179] Power measurements are determined using the measured voltage, current and determined frequency. As is well known to those of ordinary skill, the power calculations include active (real) power, apparent power, reactive power and power factor, which may be determined using the following equations:
[0180] Active Power (Watts)
P = V rm s × I r m s × cos φ = 1 N ∑ N ( V i nst × I i nst ) Equation 1
[0181] Apparent Power (VA)
S=V rms ×I rms Equation (2)
[0182] Reactive Power (VARs)
Q = V r m s × I r m s × sin φ = 1 N ∑ N ( V inst × I - 2 ) Equation 3
[0183] Power Factor
PF = cos φ = Active Power ( Watts ) Apparent Power ( VA ) Equation 4
[0184] Where:
[0185] V inst=Instantaneous Voltage Sample
[0186] I inst=Instantaneous Current Sample
[0187] φ=Phase Angle between V & I
[0188] I-2=I inst shifted 90 electrical degrees
V rm s = 1 N ∑ n = 1 N V n 2 I rm s = 1 N ∑ n = 1 N I n 2
N = number of samples taken
[0189] Note that the VAR calculation requires that each current sample be shifted by 90 degrees, which is referred to in the equations as I −2 . The VAR calculation produces a signed quantity. A negative VAR quantity indicates a leading power factor and a positive VAR quantity indicates a lagging power factor. The number of samples per cycle is 64 (64 is divisible by 4, which allows a more accurate 90 degree phase shift and thus is believed to significantly reduce the VAR calculation error.)
[0190] The demand period for kW Demand and Amp Demand is the same and consists of a “programmable demand period (T PRG )” from 1 to 90 minutes in step such as 1, 2, 5, 10, 16, 20, 30, 60, and 90. During this demand period, the demand is calculated by first averaging the three phase currents and then summing the currents each time a new value is calculated. At the end of the period the sum is divided by the number of samples taken during the period (see Equation 5, below). The maximum demand is calculated based on the user selected “number of demand periods (N T )” (1 to 15). If N T is 1, then the maximum demand is the largest demand value that has been calculated since demand was last cleared. Setting the number of demand periods N T equal to a number greater than one allows for a sliding window calculation method. The maximum demand is the largest average demand over N T periods. Each time a new demand value is calculated, the oldest calculation is discarded and the new one is used to generate a new average.
∑ n = 1 □ ( I A + I B + I C 3 ) T PRG = AmpDemand Equation 5
[0191] Where: T PRG is a programmable demand period, and I A , I B and I C are phase currents for phases A, B and C, respectively. The kW, kW Demand, kVAR and kW Hour calculations account for reverse power flow, and indicate this with forward (line to load) and reverse (load to line) power displays on LCD 240 . Alarm and trip set-point limits may also be set for forward and reverse power levels. The Power Factor calculation indicates leading and lagging conditions.
[0192] Voltage and current are sampled such that the data of one phase is calculated while the data of another phase is sampled. For example, phase A data is calculated while phase B data is sampled, phase B data is calculated while phase C data is sampled, and phase C data is calculated while neutral data is sampled. Either the host computer 140 , PC 117 or EID 200 may retrieve monitored parameter values and clear the monitored parameter log.
[0193] The protective features implemented in the Protective microprocessor 214 and the Protective Relay functions implemented in the Energy Information/Communications microprocessor 222 allow it to trip the contactor portion of circuit breaker 116 when certain events occur or to activate the alarm signal to either sound an alarm or open the circuit breaker 116 , depending on the system configuration selected by the user. Table II lists the events for which the Protective microprocessor 214 may trip the circuit breaker 116 and the parameters that may be stored in the trip log when the circuit breaker is tripped. In particular, I X indicates the present current in phase X. V X-Y indicates the present voltage measured from phase X to phase Y, V AVE indicates the average phase-to-phase voltage, KW, KVAR and KVA indicate the present value of real power, reactive power and apparent power, respectively.
TABLE II Cause of Trip Parameters logged Long Time I A , I B , I C , I N , & I G Short Time I A , I B , I C , I N , & I G Instantaneous I A , I B , I C , I N , & I G Ground Fault I A , I B , I C , I N , & I G Over Neutral Current I A , I B , I C , I N , & I G Current Unbalance I A , I B , I C , I N , & I G Over Voltage V A-B , V B-C , V C-A & V AVE Under Voltage V A-B , V B-C , V C-A & V AVE Voltage Unbalance V A-B , V B-C , V C-A & V AVE Over Frequency Freq., V A-B , V B-C , V C-A & V AVE Under Frequency Freq., V A-B , V B-C , V C-A & V AVE Reverse Power KW, KVAR, and KVA
[0194] Table III lists the events and associated parameters that are logged in the event log.
TABLE III Over Neutral Current I A , I B , I C , I N , & I G Current Unbalance I A , I B , I C , I N , & I G Under Voltage V A-B , V B-C , V C-A & V AVE Voltage Unbalance V A-B , V B-C , V C-A & V AVE Over Voltage V A-B , V B-C , V C-A & V AVE Reverse Power KW, KVAR, and KVA Over Frequency Freq., V A-B , V B-C , V C-A & V AVE Under Frequency Freq., V A-B , V B-C , V C-A & V AVE Over Current I A , I B , I C , I N , & I G Ground Over Current I A , I B , I C , I N , & I G Over Amp Demand Amp Demand, I A , I B , I C Over KW KW, KVARs, KVA Over KW Demand Watt Demand, Instantaneous Watts Over KVA KW, KVARs, KVA Over KVAR KW, KVARs, KVA Over Leading PF Total Power Factor, I A , I B , I C Under Lagging PF Total Power Factor, I A , I B , I C Over THD Total Harmonic Distortion, I A , I B , I C , I N
[0195] The Protective Relay features include: Neutral Over Current, Current Unbalance, Under Voltage, Voltage Unbalance, Over Voltage, Reverse Power, Over Frequency, and Under Frequency appear in both the Trip Log and the Event Log. The Protective Relay features can be configured by the user to alarm or to alarm and trip (alarm is automatically enabled when trip is enabled). When a Protective Relay feature's alarm is enabled and the alarm pickup and delay are exceeded, the event is logged in the Event Log and the Protective microprocessor 214 is instructed to signal the alarm. When the trip's pickup and delay settings are exceeded, the event is logged in the Trip Log and the Protective microprocessor 214 is instructed to trip.
[0196] The Alarm features include: Over Current, Ground Over Current, Over Amp Demand, Over KW, Over KW Demand, Over KVA, Over KVAR, Over Leading Power Factor, Under Lagging Power Factor, and Over Total Harmonic Distortion only appear when an Alarm function is enabled. When its pickup and delay are exceeded, the event is logged in the Event Log and the Protective microprocessor 214 is instructed to signal the alarm. The alarm features which the EID may recognize are listed in Table III. All of these events are recognized by the Protective microprocessor 214 or Energy Information/Communications microprocessor 222 .
[0197] Table IV lists exemplary alarm ranges of various parameters measured by EID 200 .
TABLE IV Alarm event Measured Parameter Alarm Range Over current (phase) I A , I B & I C 115%-250% of Ir Over current (ground) I G 20%-100% of In Over current (demand) I A , I B & I C 60%-100% of Ir Total Harmonic Distortion Frequency 5%-50% Over KW KW 20-5300 kW Over KW Demand KW 20-5300 kW Over KVA KVA 20-5300 kVA Over KVAR KVAR 20-5300 kW Over Power factor (leading) PF .50-.95 Under Power Factor (lagging) PF .50-.95
[0198] The protective features which the EID may recognize are listed in Table V. These events are recognized by the Protective microprocessor 214 or Energy Information/Communications microprocessor 222 .
TABLE V Protective Function Measured Parameter Pick-up Range Over current I N 115%-250% of Ir (neutral) Current Unbalance I A , I B & I C 5%-50% Under Voltage V A-B , V B-C & V C-A 50%-95% of Vr Voltage Imbalance V A-B , V B-C & V C-A 5%-50% Over Voltage V A-B , V B-C & V C-A 105%-125% of Vr Over Reverse Power Reverse KW 20-5300 kW Over Frequency Frequency 1-12 Hz above nominal Under Frequency Frequency 1-12 Hz below nominal
[0199] The Energy Information/Communications microcomputer 222 maintains three logs for reporting significant events: the trip log, the event log and the min/max log. The trip log is a nonvolatile memory which holds the last five trip events that have occurred. The trip log stores the data and time of the event, as well as the data associated with the event. The event log is a volatile memory which holds the ten most recent alarm events, including the start time and date of each event, the end time and date of each event and the data associated with each event. The min/max log holds the minimum and/or maximum energy information values in a volatile memory. The min/max values are time stamped to the nearest second. Examples of the data stored in the min/max log are: current, voltage, VA, watt demand, frequency, crest factor, watts, VARS, power factor, and THD. The data contained in each log is available at the LCD 240 . These logs may also be read by the host computer 140 and PC 117 . EID 200 also has operation counters to record the number and types of events that occur in the circuit breaker 116 . In the present embodiment, three count values are maintained in non-volatile memory by the EID 200 : 1) a mechanical count value; 2) an interruption level count value; and 3) a fault count value. The information held by each count value is further described below.
[0200] The mechanical count value records the total number of circuit breaker openings, but does not determine the reason the circuit breaker opened. For example, the mechanical count may reflect the number of circuit breaker openings due to electrical overload, the number of fault openings and the number of operator induced openings. The mechanical count may be displayed on LCD 240 through a menu selection. In the present embodiment, the mechanical count and the circuit breaker serial number may be displayed. This count may also be read using the communication ports by the host computer 140 or PC 117 . The interruption level count records the number of times the circuit breaker tripped and a respective current range representing the circuit breaker current when the trip occurred.
[0201] The number and span of the current ranges may be user selectable or predetermined in the EID software. In the present embodiment, the ranges are preset to: 1) less than 100% of contact rating (CT); 2) 100% to 300% CT; 3) 300% to 600% CT; 4) 600% to 900% CT: and 5) greater than 900% CT. These ranges are exemplary and any suitably appropriate number ranges and range spans may be used. The interruption level count may be displayed on LCD 240 through a menu selection. This count may also be read using the communication ports by the host computer 140 or PC 117 . Finally, the fault count value reflects the faults and the number of trips. In the present embodiment the faults are listed by type of protection, such as: 1) overload; 2) short time; 3) instantaneous; and 4) ground fault. The display lists the fault type in one column and the respective fault count in a second column. In addition, the total number of trips due to these faults may also be displayed.
[0202] As discussed above, a menu system is used to select and control a variety of display modes, pick-up points, delays, etc. of the EID 200 . On startup, the highest level menu selections are displayed. The exemplary selections are: “SYSTEM CONFIG”; “PROTECTIVE”; “METERING”; “COMMUNICATIONS”; “LOGS”; “OPERATIONS”; “SECURITY”; and “VIEW DATA”. The main menu of the present invention is shown in FIG. 6A. When the EID 200 has been inactive for approximately five minutes, it enters an idle display mode. The idle display mode may be a blank screen or a cyclic display of informational screens, such as date, time, etc. Pressing any key, such as the ESC 414 key terminates the idle display mode and activates the highest level menu.
[0203] The System Configuration menu has selections for Viewing Configuration Information and Frequency, Wiring, PT Rating, Short Circuit Protection, External Neutral Sensor, Time & Date, LCD Contrast, and Breaker Serial Number settings. The Protective menu has selections for the Viewing Protective Settings, and establishing the Long Time, Short Time, Instantaneous, Ground Fault, Alarms and Relay settings. The energy information or metering menu has selections for Metered Data, Demand Configuration and Resetting the
[0204] Metered Data. Additionally, the Communication menu has selections for Viewing the Communication Configuration, setting ACCESS/EIA-485 baud rate, setting the EMU's ACCESS device address, setting EIA-232 baud rate and Remote Trip/Open enable/disable. The Logs menu has selections for the Event Log, the Trip Log, and the Min-Max Log as well as clearing each of the logs. The Operations menu has selections for Breaker Test and the various counters; mechanical operations, fault by level and faults by type. The Security menu has selections for entering and changing passwords and enabling security. Table VI provides an outline of the menu system hierarchy of the present embodiment as follows.
TABLE VI System Config View Config Frequency Wiring PT Rating Short Circuit Prot Ext. Neutral Sensor Time and Date LCD Contrast Breaker S/N Protective View Settings Long Time Short Time Instantaneous Ground Fault Alarms Over Current Ground Over Current Over Amp Demand Total Harmonics Over KW Over KW Demand Over KVAR Over KVA Under Power Factor Lagging Over Power Factor Leading Protective Relays Neutral Over Current Current Unbalance Under Voltage Voltage Unbalance Over Voltage Over Reverse Power Over Frequency Under Frequency Metering Metered Data Volts, Amps, Power Factor, and Frequency Watts, Volt-Amps Reactive, Volt-Amps, and Crest Factor Demand Harmonics Current Data A Current Graphs B Current Graphs C Current Graphs N Current Graphs Waveforms Phase A Graphs Phase B Graphs Phase C Graphs Phase N Graphs Phase Balance Voltage Balance Current Balance Demand Config Reset Meter Data Energy Registers Demand Communication View Communications Configuration ACCESS BAUD Rate Slave Address RS232 BAUD Rate Remote Trip/Close Logs View Event Log ↑ (Scroll up through Log) ↓ (Scroll down through Log) Reset Event Log View Trip Log ↑ (Scroll up through Log) ↓ (Scroll down through Log) Reset Trip Log View Min/Max Log Amps and Crest Factor Phase A Amps Phase B Amps Phase C Amps Average Phase Amps Phase N Amps Ground Amps Amps Demand Phase A Crest Factor Phase B Crest Factor Phase C Crest Factor Volts Phase A Volts Phase B Volts Phase C Volts AB Line Volts BC Line Volts CA Line Volts Average Line Volts Power Instantaneous Watts Instantaneous VARs Instantaneous VA Watt Demand Power Factor and Frequency Phase A Power Factor Phase B Power Factor Phase C Power Factor Total Power Factor Frequency Total Harmonic Distortion Phase A THD Phase B THD Phase C THD Neutral THD Reset Min/Max Log Operations Breaker Test Mechanical Counter Interruption Level Fault Counter Security Enable Security Change Password Enter Password View Data
[0205] By using the menu system, the user may select and display any number of conditions of the EID 200 in various combinations. For example, the user may select a histogram display of phase frequency harmonics in combination with a voltage signal display. The number and combination of displays is generally limited by the display resolution and the capacity of the display memory.
[0206] Referring to FIGS. 6 A- 6 F, a procedure for using the menu system is now described. Once the main menu (FIG. 6A) is displayed (at power on or exit of idle display mode) the operator may press keys 408 and 410 to scroll up and down, respectively, through the available selections to highlight one of the displayed selections. To activate a highlighted selection, the operator presses key 412 . For example, from the main menu, if the operator wishes to enter the energy information or metering feature, key 410 may be pressed twice or key 408 may be pressed five times (to scroll from the last displayed selection). Alternatively, keys 410 or 412 may be pressed and held by the operator to allow the highlighted selection to automatically scroll through the selections. The operator releases the depressed key when the desired selection is highlighted by highlight bar 602 . Highlight bar 602 may be accomplished, for example, by inverting the selected item, flashing the selected item, or changing the color of the selected item.
[0207] [0207]FIG. 6B shows the metering menu selected as described above. As is shown in FIG. 6B and in Table V, this menu shows another layer of selections. In this example, “METERED DATA”, “DEMAND CONFIG” and “RESET METER DATA” are available. Again, by moving the highlight bar 602 with keys 408 and 410 , and selecting with key 412 yet another menu layer may be displayed. Assuming that the operator selected “METERED DATA” then the FIG. 6C menu is displayed. Referring to FIG. 6C, the data display provides “V, A, PF, and Freq”, “W, VAR, VA, and CF, Demand, Harmonics, “WAVEFORMS”, and “PHASE BALANCE” selections. Once again, by moving the highlight bar 602 with keys 408 and 410 and selecting with key 412 , another menu layer or data may be displayed. If the operator selected “DEMAND”, the FIG. 6D demand data screen is displayed providing the operator with an alphanumeric display of current and power demand. As mentioned above, waveform data may also be displayed on display 240 . In this example, if the operator highlights and selects “WAVEFORMS”, the FIG. 6E WAVEFORM GRAPHS menu is displayed. Selecting the “PHASE A GRAPHS” option results in the display of the FIG. 6F waveforms.
[0208] As mentioned above, the present embodiment is not limited to displaying singular menu selection data. Multiple waveforms, waveforms and histograms, waveforms and alphanumeric data, histograms and alphanumeric data, etc. may be displayed on display 240 using the appropriate menu selections. Furthermore, the menu selections shown in Table 5 are exemplary and any other appropriate menu hierarchy and selection options may be used depending on system requirements. The menu system may further include a language selection allowing the operator to set the system language to a language other than English, such as, for example: French, German and Italian.
[0209] FIGS. 7 A- 7 J further show various display types available to the user for setting a variety of pick-up points and delays, as well as alphanumeric readouts of the circuit breaker conditions. It is understood that FIGS. 7 A- 7 J are exemplary and do not reflect the entire extent to which the present system may be used to set and display parameters of circuit breaker 116 . As set forth above, multiple displays such as those shown in FIGS. 7 A- 7 J may be simultaneously displayed on display 240 . As shown in FIG. 7A, over current pick-up 700 and delay 702 may be set in a bar graph mode. In addition, an alarm condition may be activated by selecting over current alarm 704 . FIGS. 7 B- 7 F show other exemplary settings available in EID 200 through front panel 400 . These settings may also be made using the communications ports 246 , 248 . FIGS. 7G through 7J show alphanumeric displays of the protective configuration, voltage, current and phase conditions, and demand of the EID 200 . The information shown in FIGS. 7A to 7 J are merely exemplary of the data available to the user.
[0210] Security is a concern in any industrial environment. Inadvertent and purposeful interruptions of power to a section of a factory may have severe financial, safety, and other impacts. Furthermore, tampering with the set-points of a programmable circuit breaker may ultimately damage the protected equipment. The present embodiment is believed to address such concerns by incorporating security features accessible through the menu system. The exemplary security system may be accessed by selecting the SECURITY entry point of the main menu. This allows a user with a valid password to enable or disable the security features, as well as to change the security password. To prevent lockout if the password is lost or forgotten, the security system has a backdoor password which may for example be based on the current date. A password protection system sets a flag when security is active and checks the flag before executing any routine interpreting data from the front panel, except when the front panel data contains the proper password. In addition, the menu based security system will not affect host computer 140 or PC 117 accessibility of the circuit breaker 116 . It is contemplated that the resident software in each of the host computer 140 or and PC 117 includes another security system.
[0211] [0211]FIG. 8A is a graph of the trip curve 810 , and FIG. 8B is a curve illustrating how the ground-fault trip function is implemented on a system that provides a ground sensor input signal to the trip unit. In FIG. 8A, the point A coordinates on the solid-line curve 810 represent the pickup current and delay parameters of the long-time trip setting. The point C coordinates represent pickup current and delay parameters for the short-time trip setting and the point D current coordinate represents the instantaneous trip current. Point B on the curve 810 is determined as the intersection of a fixed slope line, originating at the long-time trip coordinates, and a line drawn vertically from the short-line trip coordinate. This line is referred to as an I 2 T curve. The sloped line between points C and D is a fixed-slope line originating at the short-time trip coordinates and intersecting a line drawn vertically from the instantaneous trip coordinate. The broken line 811 illustrates the trip function without this short-time I 2 T curve. The solid line 810 defines the pickup and trip functions performed by the Protective microprocessor 214 . A pickup occurs whenever the current sensed on one of the phases can be mapped onto the curve 810 . The circuit breaker 116 is not tripped, however, until after the time delay indicated by the time coordinate of the trip curve at the pickup current value. Finally, the ground fault curve shown in FIG. 8B consists of two points, a variable trip coordinate E, which may be specified by the operator using the front-panel switches 410 , 412 , 414 , and a short-time trip coordinate F which is automatically set to a current that is 1.5 times the specified ground-fault pickup value and a delay of one-half second. The slope between the points E and F is a fixed-slope I 2 T curve drawn between the variable trip coordinate and the resulting short-time trip coordinate.
[0212] Referring to FIG. 9A, circuit breaker 116 is shown in a relatively simple configuration as installed in the field. As shown in FIG. 9B, circuit breaker 116 may be upgraded in the field by the user by installing EID 200 into circuit breaker 116 . A connector 702 in the rear portion of EID 200 mates with a connector 704 of circuit breaker 116 . Referring to FIG. 9C, EID 200 is shown installed in circuit breaker 200 .
[0213] Energy Information/Communications microprocessor 222 uses an interrupt scheme to direct control to components that requiring attention. This interrupt structure and operation are as follows:
[0214] For Energy Information/Communications microprocessor 222 , each interrupt source, whether internal or external, has an associated Interrupt Level, Interrupt Arbitration Value and Interrupt Vector Value. The Interrupt Level establishes the interrupt priority. The Interrupt Arbitration Value is used by the Energy Information/Communications microprocessor 222 to settle contention between two equal priority interrupts. The Interrupt Vector Number determines which interrupt handler will service the interrupt. It is believed to be preferable to assign Interrupt Levels and Interrupt Arbitration Values for each software module used by Energy Information /Communications microprocessor 222 that will generate interrupts. It is also believed to be preferable to provide a Vector Value for each user defined interrupt. Certain interrupts, such as Reset for example, have predefined Interrupt Vector Values.
[0215] In the present embodiment, there are seven interrupt levels. In the present embodiment, interrupt level 1 has the lowest priority and interrupt level 7 has the highest priority. Interrupt recognition is based on the states of the interrupt request signals 1 through 7 and the 3-bit interrupt priority (IP) field in the Energy Information/Communications microprocessor 222 Condition Code Register (CCR). Binary values of 000 to 111 provide eight priority masks. All interrupts having priorities less than 7 may be masked (disabled). When the IP field equals 000, no interrupts are masked. Only interrupts with a priority greater than the IP field mask are recognized and processed. During interrupt processing the IP field is set to the priority of the interrupt being serviced. Exception processing for multiple exceptions is done by priority, from highest to lowest. If an interrupt request of equal or lower priority than the current IP mask value is generated, Energy Information/Communications microprocessor 222 does not recognize the interrupt. Therefore, for an interrupt to be serviced it must remain active until acknowledged by Energy Information/Communications microprocessor 222 .
[0216] Each software module that generates an interrupt has a 4-bit Interrupt Arbitration (IARB) field in its configuration register. These bits may be assigned a value from 0001 (lowest priority) to 1111 (highest priority). A value of 0000 in an IARB field causes Energy Information/Communications microprocessor 222 to process a spurious interrupt exception when an interrupt from that module is recognized. When two or more modules, which have been assigned the same priority level, request interrupt service essentially simultaneously, the IARB fields of the requesting modules are used to determine which interrupt request is recognized. Therefore, each module must have a unique IARB field. If two contending modules have their IARB fields set to the same value, Energy Information/Communications microprocessor 222 may interpret multiple vector values simultaneously with unpredictable consequences. When arbitration is complete, the dominant module supplies an Interrupt Vector Value.
[0217] As mentioned above, each interrupt has an associated vector value. The vector value is used to calculate a vector address in a data structure called the Exception Vector Table. An exception is an event, such as an interrupt, that can preempt the normal instruction process. In the present embodiment, the Exception Vector Table is located in the first 512 bytes of Energy Information/Communications microprocessor 222 address space. The Exception Vector Table contains the addresses of the exception (interrupt) handler routines. All vectors except the Reset vector consist of one word (2 bytes). The Reset vector consists of 4 words (8 bytes). There are 52 pre-defined or reserved vector values and approximately 200 user assignable vector values. There is a direct mapping of vector number to vector table address. Energy Information/Communications microprocessor 222 multiplies the vector value by two to convert it to a vector table address. Table VII is an exemplary Exception Vector Table.
TABLE VII VECTOR VECTOR TABLE VALUE ADDRESS TYPE OF EXCEPTION 00 0000-0006 Reset 04 0008 Breakpoint 05 000A Bus Error 06 000C Software Interrupt 07 000E Illegal Instruction 08 0010 Division by Zero 09-0E 0012-001C Unassigned, Reserved 0F 001E Uninitialized Interrupt 10 0020 Unassigned, Reserved 11 0022 Level 1 Interrupt Autovector 12 0024 Level 2 Interrupt Autovector 13 0026 Level 3 Interrupt Autovector 14 0028 Level 4 Interrupt Autovector 15 002A Level 5 Interrupt Autovector 16 002C Level 6 Interrupt Autovector 17 002E Level 7 Interrupt Autovector 18 0030 Spurious Interrupt 19-37 0032-006E Unassigned, Reserved 38-FF 0070-01FE User Defined Interrupts
[0218] Exception processing may be performed in four distinct phases.
[0219] 1. The priority of all pending exceptions is evaluated and the highest priority exception is processed first.
[0220] 2. The processor state is stacked, then the CCR PK extension field cleared.
[0221] 3. An Interrupt Vector Value is acquired and converted to a vector table address that is used to select the address of an exception handler routine from the vector table.
[0222] 4. The address of the selected exception handler routine is loaded into the program counter and the processor jumps to the exception handler routine. All addresses for exception handler routines, except for Reset, are 16-bit addresses. Therefore, it is preferable that the routines be located either within the first 512 bytes of memory or that the vectors point to a jump table.
[0223] The present embodiment also uses up to nine external interrupts sources. The external interrupts may be divided into external system interrupts and external device interrupts. The external system interrupts are Reset and Breakpoint. Their Interrupt Vector Values and respective priorities are pre-defined. The external device interrupts are IRQ1 through IRQ7 and are associated with interrupt levels 1 through 7, respectively. As mentioned above, level 1 has the lowest priority and level 7 has the highest priority. In the present embodiment, IRQ1 through IRQ6 are active-low level sensitive inputs, while IRQ7 is an active-low edge sensitive input. Interrupts IRQ1 through IRQ6 are maskable, while IRQ7 is non-maskable. Energy Information/Communications microprocessor 222 treats external interrupt sources as though they are part of the System Integration Module (SIM). Therefore the IARB field in the SIM's configuration register is used to arbitrate between external interrupts and interrupts generated by other internal modules.
[0224] When an external device interrupt wins arbitration, a vector value is supplied to invoke the appropriate interrupt handler. The external device that generated the interrupt signal can supply a vector value or Energy Information/Communications microprocessor 222 can supply an autovector number. In the present embodiment, there are 7 autovectors. Each one is associated with an external interrupt. There are five ways the response can be implemented when an external device interrupt wins arbitration, and they are as follows:
[0225] 1. The external device that generated the interrupt signal can provide Energy Information/Communications microprocessor 222 with the Interrupt Vector Value of an interrupt handler and generate a Data Size Acknowledge (DSACK) response for Energy Information/Communications microprocessor 222 . The external device that requested interrupt service decodes the priority value on address lines A 1 -A 3 . If the priority value equals that device's priority level, the external device places a vector value on data lines D 8 through D 15 (if the device is an 8-bit port) or data lines D 0 through D 7 (if the device is a 16-bit port) and generates the appropriate 8-bit or 16-bit DSACK signal. If the SIM module wins arbitration, the Interrupt Vector Value supplied by the external device is used to select the interrupt handler.
[0226] 2. The external device that generated the interrupt signal can pull the Autovector (AVEC) input to Energy Information/Communications microprocessor 222 low to request that Energy Information/Communications microprocessor 222 supply the appropriate Autovector value. The external device that requested interrupt service decodes the priority value on address lines A 1 through A 3 . If the priority value equals that device's priority level, the external device asserts the AVEC signal. If the SIM module wins arbitration, the appropriate Autovector value is generated.
[0227] 3. A chip select pin of Energy Information/Communications microprocessor 222 can be programmed to decode the interrupt acknowledge bus cycle, generate an interrupt acknowledge signal to the external device, and generate a Data Size Acknowledge (DSACK) response for Energy Information/Communications microprocessor 222 . Program the appropriate chip select pin assignment register (CSPAR 0 or CSPAR 1 ) to configure the chip select to select an 8-bit port ( 10 ) or a 16-bit port ( 11 ). Program the base address register (CSBAR) of the chip select with a base address field (bit A 3 through A 15 ) of all ones. The block size is programmed to no more than about 64 K bytes so that the address comparator checks address lines A 16 through A 19 against the corresponding bits in the base address register. The appropriate chip select options register (CSOR) are programmed as follows:
[0228] a. Set the MODE bit to asynchronous mode (0).
[0229] b. Set the BYTE field to lower byte (01) when using a 16 bit port, since the external vector for a 16 bit port is fetched from the lower byte. Set the BYTE field to upper byte ( 10 ) when using a 8 bit port.
[0230] c. Set the RIW field to read only (01).
[0231] d. Set the STRB bit to synchronize with AS (0).
[0232] e. Set the DSACK field to the desired number of wait states.
[0233] Select External (1111) if the external device will generate DSACK signals.
[0234] f. Set the SPACE field to CPU space (00).
[0235] g. Set the IPL field to respond to the desired interrupt request level, or to 000 to respond to all request levels.
[0236] h. Set the AVEC bit to 0 to disable autovector generation.
[0237] 4. A chip select can be programmed to generate an AVEC response instructing Energy Information/Communications microprocessor 222 to supply the appropriate autovector value.
[0238] a. Program the appropriate chip select pin assignment register (CSPAR 0 or CSPAR 1 ) to configure the chip select pin you have chosen for either discrete output (00) or its alternate function (01). This prevents the pin from being asserted during interrupt acknowledge cycles.
[0239] b. In the base address register (CSBAR) of the chip select pin you have chosen, program the base address field (bit 3 through 15 ) to all ones. Program the block size to no more than 64 K so that the address comparator checks address lines 16 through 19 against the corresponding bits in the base address register. (The CPU places the CPU space type on address lines 16 through 19 .)
[0240] c. Program the appropriate chip select options register (CSOR) as follows:
[0241] i. Set the MODE bit to asynchronous mode (0).
[0242] ii. Set the BYTE field to both bytes (11).
[0243] iii. Set the RAN field to read/write (11).
[0244] IV. Set the STRB bit to synchronize with AS (0).
[0245] v. Set the DSACK field to 0 wait (0000).
[0246] vi. Set the space field to Supervisor space (10).
[0247] vii. Set IPL to respond to the desired interrupt request level, or to 000 to respond to all request levels.
[0248] viii. Set the AVEC bit to 1 to enable autovector generation.
[0249] 5. The Energy Information/Communications microprocessor 222 AVEC pin may be permanently wired low (asserted) to generate the appropriate Autovector value for any external interrupt request that wins arbitration. When the Autovector pin is wired low (asserted) and any external device interrupt wins arbitration, the SIM supplies the Interrupt Vector Value of the Autovector associated with that external interrupt. This is the approach used in the present embodiment.
[0250] The System Integration Module (SIM), Queued Serial Module (QSM), and General Purpose Timer module (GPT) may be sources of internal interrupts. The sources of internal SIM interrupts are the Software Interrupt, the Periodic Timer, bus errors, illegal instructions, division by zero, un-initialized interrupts, and spurious interrupts. The QSM can generate interrupts to signal SPI Finished, SCI Transmitting, SCI Transmit Complete, SCI Receive, and SCI Line Idle. The interrupt sources from the GPT are Input Captures 1 through 3, Output Compares 1 through 4, the programmable Input Capture-4 or Output Compare 5, Timer Overflow, Pulse Accumulator Overflow, and Pulse Accumulator Input. To use these internal interrupt sources their respective modules must be configured for interrupts and the individual interrupts must be enabled.
[0251] In addition to handling the exemplary nine external interrupts, the SIM has seven interrupt sources and seven interrupt vectors. The Interrupt Vector Values and Interrupt Priority Levels for the Software, Bus Error, Illegal Instruction, Division by Zero, Un-Initialized, and Spurious interrupts are pre-defined in the exemplary embodiment. The Exception Vector Table (Table VI above) has the Interrupt Vector Values of these interrupts. The Interrupt Vector Value and Interrupt Priority Level are user defined for the Periodic Timer interrupt.
[0252] To configure the System Integration Module interrupts, the following to steps may be used. First, in the SIM Module Configuration Register (SIMCR), set the Interrupt Arbitration field (IARB) to the interrupt arbitration number you have selected for the SIM module. Valid values are from 0001 (lowest priority) to 1111 (highest priority). Second, to use the Periodic Timer interrupt, configure the PIRQL and PIV fields In the Periodic Interrupt Control Register (PICR) by setting the PIRQL field to the selected Interrupt Level. Valid values are from 001 (lowest) to 111 (highest)or by setting the PIV field to the selected Interrupt Vector Number.
[0253] The Queued Serial Module consists of the Serial Communications Interface (SCI) and Queued Serial Peripheral Interface (QSPI) sub-systems. In the present embodiment, the SCI has four possible interrupt sources, but only one interrupt vector. The SCI interrupt sources are Transmit Data Register Empty, Transmit Complete, Receive Data Register Full and Idle Line Detected. When the Energy Information/Communication microprocessor 222 responds to an SCI interrupt, the SCI interrupt handler must determine the exact interrupt cause by reading the appropriate bits (TDRE, TC, RDRF, and IDLE) in the SCI Status Register (SCSR). The QSPI has three possible interrupt sources, but only one interrupt vector. These interrupt sources are QSPI Finished, Mode Fault and Halt Acknowledge. When the Energy Information/Communication microprocessor 222 responds to a QSPI interrupt, the QSPI interrupt handler must determine the exact interrupt cause by reading the appropriate bits (SPIF, MODF, and HALTA) in the QSPI Status Register (SPSR). The following steps may be used to configure the Queued Serial Module interrupts.
[0254] In the QSM Configuration Register (QMCR), set the IARB field to the interrupt arbitration number you have selected for the QSM module. Valid values are from 0001 (lowest priority) to 1111 (highest priority). In the QSM Interrupt Level Register (QILR), set the ILQSPI field is set to the selected Interrupt Level for the QSPI sub-system and set the ILSCI field to the selected Interrupt Level for the SCI sub-system. Valid values are from 001 (lowest) to 111 (highest). In the QSM Interrupt Vector Register (QIVR), the INTV field is set to the selected Interrupt Vector Number. The low order bit in the INTV field is cleared during an SCI interrupt and set during a QSPI interrupt. In the QSPI Control Register 2 (SPCR 2 ), the SPIFIE bit may be set to enable QSPI interrupts. Finally, in SCI Control Register 1 (SCCR 1 ) the TIE bit is set to enable Transmit Data Register Empty interrupts, the TCIE bit is set to enable Transmit Complete interrupts, the RIE is set to enable Receive Data Register Full interrupts, and the ILIE bit is set to enable Idle Line Detect interrupts.
[0255] The General Purpose Timer (GPT) Module consists of the capture/compare unit, the pulse accumulator unit and the pulse-width modulation unit. The GPT has 11 interrupt sources and 12 interrupt vectors. There are 3 Input Capture interrupts, 4 Out Compare interrupts, a programmable Input Capture 4 or Output Compare 5 interrupt, plus the Timer Overflow, Pulse Accumulator Overflow and Pulse Accumulator Input interrupts. Any one of these interrupt sources can be selected (adjusted) to have priority over all other GPT interrupt sources. The Interrupt Vector value for each interrupt source is created by combining a high nibble selected by the programmer, called the Interrupt Vector Base Address (IVBA), and a low nibble supplied by the GPT. Table VIII shows the GPT Source Number and Interrupt Vector Value for each GPT interrupt. The lower the GPT Source Number, the higher the priority of the interrupt.
TABLE VIII Interrupt Source GPT Source Value Vector Value Adjusted Channel 0000 IVBA: 0000 Input Capture 1 (IC1) 0001 IVBA: 0001 Input Capture 2 (IC2) 0010 IVBA: 0010 Input Capture 3 (IC3) 0011 IVBA: 0011 Output Compare 1 (OC1) 0100 IVBA: 0100 Output Compare 2 (OC2) 0101 IVBA: 0101 Output Compare 3 (OC3) 0110 IVBA: 0110 Output Compare 4 (OC4) 0111 IVBA: 0111 Input Capture 4/Output 1000 IVBA: 1000 Compare 5 (IC4/IOC5) Timer Overflow (TO) 1001 IVBA: 1001 Pulse Accumulator 1010 IVBA: 1010 Overflow (PAOV) Pulse Accumulator Input 1011 IVBA: 1011 (PAI)
[0256] The General Purpose Timer Module interrupts may be configured using the following procedure:
[0257] In the GPT Configuration Register (GOTMCR), set the IARB field to the interrupt arbitration number selected for the GPT module. Valid values are from 0001 (lowest priority) to 1111 (highest priority). In the GPT Interrupt Configuration Register (ICR) set the following fields: (a) set the interrupt Priority Adjust field (IPA) to the GPT Source Number of the GPT interrupt source you wish the module to give the highest priority; (b) set the Interrupt Priority Level field (IPL) to the selected Interrupt Priority Level of GPT interrupt requests, where valid values are from 000 (lowest) to 111 (highest):(c) set the Interrupt Vector Base Address field (IVBA) to the value of the high nibble of the Interrupt Vector Values the GPT module will use. Also enable the interrupts in the Timer Interrupt Mask Register (TMASK) as follows: (a) set PAII (TMASK, bit 4 ) to enable the Pulse Accumulator Input interrupt; (b) set PAOVI (TMASK, bit 5 ) to enable the Pulse Accumulator Overflow interrupt; (c) set TOI (TMASK, bit 7 ) to enable the Timer Overflow interrupt; (d) set ICI 1 (TMASK, bit 8 ) to enable the Input Capture 1 interrupt; (e) set IC12 (TMASK, bit 9 ) to enable the Input Capture 2 interrupt; (f) set IC13 (TMASK, bit 10 ) to enable the Input Capture 3 interrupt; (g) set OCI 1 (TMASK, bit 11 ) to enable the Output Compare 1 interrupt; (h) set OCI 2 (TMASK, bit 12 ) to enable the Output Compare 2 interrupt; (i) set OCI 3 (TMASK, bit 13 ) to enable the Output Compare 3 interrupt; (j) set OCI 4 (TMASK<Bit 14 ) to enable the Output Compare 4 interrupt; (k) set I 4 / 05 I (Tmask, bit 15 ) to enable the Input Capture 4/Output Compare 5 interrupt. The exemplary Interrupt Assignments are listed in Table IX.
TABLE IX Module Interrupt & IARB Level Vector Application OC1 GPT:1111 6 40 Initiates A/D conversion IC1 GPT:1111 6 41 Signals A/D conversion complete IC2 GPT:1111 6 42 Signals A/D data ready IC3 GPT:1111 6 43 Trip Clock Signal from Protective μP IC4 GPT:1111 6 48 Zero crossings for frequency calculation SWI SIM:1110 N/A 6 Used by μC/OS for context switching PIT SIM:1110 4 60 Generates the time tick for μC/OS IRQ4 SIM:1110 4 14 RS-232 UART data transfer SCI QSM:1101 4 50 RS-485 data transfer QSPI QSM:1101 4 51 Protective μP/Metering μP data transfer
[0258] [0258] TABLE X Memory Chip Base Block Size Assert Select Address (bytes) Select On Device Boot ROM 0000h Reads External EPROM select (high & low bytes) 0 256K not used 1 not used 2 60000h 64K Reads & External RAM select Writes (high byte) 3 60000h 64K Reads & External RAM select Writes (low byte) 4 n/a n/a n/a Port Bit used as LCD CS 5 7D800h 2K Reads & LCD Writes 6 7E800h 2K Reads & A/D Converters Writes 7 7E000h 2K Writes LCD Contrast Latch 8 7F000h 2K Reads & RS-232 UART Writes 9 7F800h 2K Reads & Real Time Clock Writes 10 7F800h 2K Reads Real Time Clock (output enable)
Operating System of the Present Embodiment
[0259] All of the features described above for the Energy Information/Communications microprocessor 222 are implemented through a preemptive multi-tasking real-time program which controls microcomputer operation. In a multitasking scheme, the program is divided into blocks called tasks, each of which is written as though it has exclusive access to the processor's time. The operating system is capable of directing the processor from one task to another (this is called context switching), and manages task execution on a priority basis. Task execution management is called scheduling, and the part of the operating system that does it is called a scheduler.
[0260] A preemptive multitasking system is one that is capable of interrupting a task before it has run to completion whenever a higher priority task is ready to run. The higher priority task preempts the lower priority task, and when it has finished or is suspended, the kernel returns control to the lower priority task. A multitasking approach is believed to have the following advantages: (1) tasks are scheduled according to their relative priorities since the operating system always schedules the highest priority task that is ready to run;(2) tasks that are not ready to run—those that are waiting for an event to occur—are dormant and do not consume processor time; and (3) tasks can be activated and deactivated as required for dynamic resource allocation. The program of the present embodiment consists of a main or background task and several interrupt handlers or foreground tasks. The main program uses sample values taken in response to a periodic interrupt and performs the calculations needed to generate the various monitoring values. The sampling interrupt routine samples all of the voltage and current signals over a one-second interval, squares the sample values and accumulates a sum of squares for use by the foreground task. Other interrupt handlers perform functions such as receiving communications packets from the host processor 140 and PC 117 .
[0261] Each task is a section of code that performs a portion of the work of EID 200 . Each task is assigned a priority, its own stack area. The respective stack area contains the task's stack and the state of the CPU registers at the time a context switch causes the task to become dormant. Exemplary tasks are described below. The software of the present embodiment is designed to be preemptive multitasking rather than loop controlled.
[0262] The scheduler determines when tasks will be executed. A Task is allowed to run until:(1) the task readies another task of higher priority;(2) an OS clock tick passes control to a higher priority task that is ready to run;(3) an interrupt service routine readies another task of higher priority; or(4) the task explicitly relinquishes control of the CPU by calling a time delay function. A task's CPU register set and its stack area is known as its context. When the scheduler decides to run a different task, it saves the context of the current task and retrieves the context of the task to be executed.
[0263] Preempting involves suspending a task to execute a higher priority task that has been prepared to run. An advantage of a preemptive system is that it is deterministic, since it can be determined when the highest priority task gets control of the Energy Information/Communications microprocessor 222 . The exemplary embodiment uses a preemptive operating system. In a preemptive system, operations that are called by more than one task must be reentrant. A reentrant feature or operation can be interrupted at any time and resumed at a later time without data corruption. Reentrant operations must use only CPU registers and stack variables, or must disable interrupts when accessing global variable.
[0264] With respect to the keypad, the program polls for a key press using a periodic interrupt generated by the Programmable Interrupt Timer (PIT) as a keypad poll control time base. Once a key press has been confirmed, the function Set_Key_Flag is called, which validates the key press and queues the key press into the keypad buffer. The keypad task is then activated four (4) times a second. When activated the Keypad Task checks the keypad buffer, extracts any pending key press value from the keypad buffer and makes it available to the menu software. In this way, several key presses can be queued and acted upon as time permits. In addition, if a key is held down, the key press will be reentered into the queue at a predetermined rate.
[0265] As mentioned above, the Energy Information/Communications microprocessor 222 is connected to the Protective microprocessor 214 using the Serial Peripheral Interface (SPI) 258 . The SPI data is sent in 32 byte packets. Each SPI packet contains a message type byte, a data length byte, 29 data bytes and an LRC (longitudinal redundancy check) byte. The SPI packet is arranged as follows: |MESSAGE TYPE|DATA LENGTH|DATA|LRC|. The MESSAGE TYPE byte indicates the type of data the packet contains. The DATA LENGTH byte indicates the number of bytes in the data field that contain valid data. The DATA bytes are the data that is being transmitted. The LRC byte contains the least significant byte of the sum of the message type, data length, and data bytes.
[0266] The SCI sub-system handles communication with the ACCESS master if circuit breaker 116 is part of an ACCESS system. In the present embodiment, this communication consists of uploading data and downloading settings. The uploaded data may consist of the breaker settings, status and current data plus the Protective microprocessor 214 and Energy Information/Communications microprocessor 222 settings, status and energy information data available from the Protective microprocessor 214 and Energy Information/Communications microprocessor 222 . The circuit breaker and metering settings can be selected remotely and downloaded to circuit breaker 116 . In the present embodiment, the ACCESS protocol operates on a serial, two-wire RS 485 network consisting of a single-bus master and up to 32 slave devices. The serial transmission format is asynchronous with one start bit, eight data bits, one stop bit and no parity. The data rate can range from 1,200 to 19,200 baud. A master device initiates all communication by sending a packet addressed to a slave device. The slave device responds with a packet if a response is required.
[0267] No slave device initiates communication. Any data that does not meet the timing or structural requirements of the ACCESS protocol is ignored by all devices. Data in ACCESS format is sent in packets containing from 5 to 260 bytes, for example. These packets are defined by framing bytes contained in their headers. These consist of a synchronization byte, an address byte, a message-type byte, a length byte (packet's data field length) and a LRC byte. The SCI packet is arranged as follows: |SYNC|DEVT|MSGT|LEN|DATA|LRC|.
[0268] The SYNC byte indicates the direction of the data transmission. Fourteen (14) hex is used for master to slave transmissions and twenty-seven hex is used for slave to master transmissions. The DEVT byte contains the address code for a specific device (direct addressing)or a general type of device (indirect addressing). The MSGT byte indicates what type of data the packet contains. The LEN byte indicates the number of bytes in the data field. The DATA bytes are the data that is being transmitted. This field can contain up to 225 bytes. With indirect addressing, the first byte in this field is the device address. Finally, the LRC is the checksum byte. It contains the inverted sum of all the bytes except the SYNC byte. The UART handles EIA-232 communications with a locally connected IBM PC or other personal computer. This communication consists of uploading data and down loading settings. The uploaded data consists of the circuit breaker settings, status and current data plus the metering or energy information settings status and data. The circuit breaker and energy information settings can be selected from the PC and down loaded to the trip unit.
[0269] Timekeeping is performed by a real time clock 234 (RTC). The RTC 234 registers are memory-mapped I/O. They include six 8-bit time/date registers plus an 8-bit command register. When reading or writing the time/date registers, a 0 is written to the TE Bit of the command register to freeze the time and date. This allows the data to be accessed without an essentially simultaneous update. This does not affect timekeeping because the RTC 234 contains internal and external time/date registers. The external registers are frozen and during a read or a write access. After the read or write, a 1 is written to the TE bit to allow the external time/date registers to be updated again. The RTC 234 is read once each second and the new date and time information is stored in the RAM 236 . This information can then be accessed by any function, such as the Event Log, that has need of the date and time.
[0270] The hardware allows sampling of the voltage and current one phase at a time. The sampling process is interrupt driven, which allows the sampling to run in the background while other tasks run in the foreground. Analog-to-Digital conversion is managed by two General Purpose Timer interrupts and their associated service routines. The interrupts are Output Compare One (OC1) and Input Capture One (IC1). When the Energy Information module needs a new sample data set for a phase, OC1 is used to start each A/D conversion. The Energy Information module uses the calculated line frequency to determine the period needed between OC1 interrupts to give exactly 64 interrupts per cycle. It then asynchronously schedules the first OC1 interrupt. The OC1 interrupt service request (ISR) reads ADC 232 A, and 232 B to start a conversion and then the next OC1 interrupt. While it is believed to be preferable to start the conversions at essentially the same time, since both ADC 232 a and 232 B cannot be read at the same time due to bus contention, they may be read consecutively. In the present embodiment, the voltage conversion starts 2.026 μs or 0.04 degrees (at 60 Hz) after the current conversion.
[0271] The IC1 interrupt is activated when both ADC 232 A and 232 B complete their respective conversions. Energy Information/Communications microprocessor 222 retrieves the result of the A/D conversions, converts the raw voltage and current data into signed data and stores the result in RAM 236 . When 384 voltage and current samples have been acquired (64 samples×6 cycles), Energy Information/Communications microprocessor 222 de-activates the OC1 interrupt and activates the Energy Information task. Thus, informing the Energy Information task that the voltage and current data sets for a particular phase are ready for processing.
[0272] When sampling phase A, the IC4 interrupt is enabled so that a zero crossing of the voltage signal for phase A causes an interrupt. When the zero crossing interrupt occurs, the value of the free running timer/counter TCNT is stored in an array. Once a second, the zero crossing array is used by a routine to determine the frequency. This routine calculates the average difference between all of the TCNT values stored in the array during sampling. This average TCNT delta and the TCNT period are used to calculate the line frequency for phase A using the formula shown below. Where System Clock Frequency =16.777 Mhz, TCNT Frequency =4.194 Mhz (System Clock /4), TCNT Period =238 nSec, and
Line_Frequency = 1 2 × Average_ TCNT _Delta × TCNT _ Period
[0273] If a phase A voltage signal is not available, the frequency is set to the programmed system frequency, 50 or 60 Hz. The Output Compare 1 (OC1) interrupt is used to start each AID conversion for sample acquisition. The occurrence of this interrupt is determined by the value stored in the Timer Output Compare 1 register (TOC1). When the free running timer/counter TCNT equals the value in the TOC1 register, an asynchronous OC1 interrupt occurs. Therefore, the sampling rate can be changed by modifying the value loaded in TOC1. For the FFT algorithm used for harmonic calculation to obtain sufficiently accurate results, it is desirable to take at least about 64 samples over one cycle. Therefore, the sample period is based on the line frequency determined from the phase A voltage signal. The following equations are used to calculate the offset to be added to TCNT and stored in the TOC1 register to correctly schedule the next OC1 interrupt, where:
OC1 _Offset = 1 Line_Frequency × TCNT _Period × Samples_per _Cycle
[0274] and TOC1=TCNT+OC 1_Offset.
[0275] Once each second the operating system activates a task to initiate sampling. This task takes the line frequency based on the data collected by the IC4 interrupt routine. It then calculates the new offset to be used by OC1 in scheduling sampling interrupts and initiates the sampling of phase A voltage and current. Sampling continues for the next six cycles for a total of 384 samples (6×64). Each time a conversion is completed, the A/D converters activate the IC1 interrupt line. The IC1 interrupt service routine reads the conversion results and stores them. When an entire data set of 384 voltage and current samples is acquired, the IC1 ISR informs the operating system that the data is ready. When the operating system is informed the phase A data is ready, it activates the energy information task. The energy information task initiates the sampling of phase B and then processes the phase A data. An exemplary method for sampling current and voltage signals is shown in Table XI and an exemplary data memory requirement is shown in TABLE XII.
TABLE XI Phase Samples Sample Start A/D Read A/D Sampled Task Taken Freq. Interrupt Interrupt A Initiate 384 64/cycle OC1 ICI Sampling B Meter 384 64/cycle OC1 ICI C Meter 384 64/cycle OC1 ICI N Meter 384 64/cycle OC1 ICI
[0276] The sequence of events listed in the table will occur once each second. Six cycles will be sampled at 64 times per cycle. When a complete set of data for a phase has been acquired, the IC1 ISR “posts” the operating system to signal that the data set is ready for processing. For both current and voltage data, each sample requires 2 bytes of memory.
TABLE XII Source Data Type Bytes Voltage A/D Voltage 768 Current A/D Current 768 Voltage Samples Sum of Squared Voltage 4 Samples Current Samples Sum of Squared Current 4 Samples Total 1544
[0277] FIGS. 11 A- 11 B are flowcharts outlining the ADC Sampling Interrupt. The ADC sampling interrupt maintains proper timing of the Energy Information Task (described below). A timer interrupt is used to select the phase to be sampled and set the sampling time interval. Sampling occurs 64 times per cycle based on the frequency calculation from the previous second. Whenever the frequency is unknown, the frequency is less than 35 Hz, or greater than 75 Hz, the sampling time interval is based on a selected system frequency. In the present embodiment, the selected system frequency is 50 Hz or 60 Hz.
[0278] It is believed that using a sampling rate of 64 samples per cycle enables faster harmonics calculations. As is well known, for the harmonics calculations to be sufficiently accurate, the determined frequency is used. Because the frequency is calculated from Phase A voltage samples in the present embodiment, if Phase A is non-functional and the other phases are at frequencies other than the programmed system frequency, the accuracy of the energy information data may not be sufficient.
[0279] Referring to FIG. 11A, at Step 1100 , the Initiate Sampling Task (described below) starts the sampling of Phase A. At Step 1101 , sampling interrupts are enabled. At Step 1102 , ADC 232 A, 232 B acquire the data from 6 cycles of voltage and current, respectively, at 64 samples per cycle for phase A. At Step 1104 , sampling interrupts are disabled. At Step 1106 , Energy Information/Communications microprocessor 222 activates the Energy Information Task (described below). At Step 1108 , the Energy Information Task changes the sampling to Phase B. At Step 1109 , sampling interrupts are again enabled. At Step 1110 , ADC 232 A, 232 B acquire the data from 6 cycles of voltage and current at 64 samples per cycle for Phase B. At Step 1112 , sampling interrupts are disabled. At Step 1114 , Energy Information/Communications microprocessor 222 activates the Energy Information Task.
[0280] Referring now to FIG. 11B, the Energy Information Task changes the sampling to Phase C at Step 1116 . At Step 1117 , sampling interrupts are enabled. At Step 1118 , ADC 232 A, 232 B acquire the data from 6 cycles of voltage and current at 64 samples per cycle for Phase C. At Step 1120 , sampling interrupts are disabled. At Step 1122 , Energy Information/Communications microprocessor 222 activates the Energy Information Task. At Step 1124 , the Energy Information Task changes the sampling to Phase N. At Step 1125 , sampling interrupts are enabled. At Step 1126 , ADC 232 A, 232 B acquire the data from 6 cycles of voltage and current at 64 samples per cycle for Phase N. At Step 1128 , sampling interrupts are disabled. At Step 1130 , Energy Information/Communications microprocessor 222 activates the Energy Information Task. At Step 1132 , the ADC sampling task is complete. The ADC 232 A, 232 B will not be started again until the Initiate Sampling Task is subsequently activated.
[0281] [0281]FIG. 12 is a flowchart showing the Initiate Sampling Task, which updates the Energy Information Task once per second. Once a second the Initiate Sampling Task is activated using an operating system time delay. Once activated, this task calculates the sampling time interval that will be used for the current one second time interval based on the frequency that was calculated during the previous one second time interval. The sampling time interval is set such that the voltage and current will be sampled 64 times per cycle. The sampling that occurs immediately after EID 200 is activated is calculated based on the selected system frequency. As mentioned above, in the exemplary embodiment, if the calculated frequency is less than 35 Hz or greater than 75 Hz, the selected system frequency is used to determine the sampling time interval. The Initiate Sampling Task is activated after the Energy Information Task completes the processing of the Phase N samples. This ensures that all of the per second energy information tasks are complete. Referring to FIG. 12, the Initiate Sampling Task is shown. At Step 1200 , the time between samples for a 64 sample per cycle sampling rate is calculated. At Step 1202 , ADC 232 A, 232 B sampling for Phase A is initiated At Step 1204 , the task is completed and awaits subsequent activation.
[0282] [0282]FIGS. 13A to 13 C are flowcharts showing the Energy Information Task. The Energy Information Task has what are believed to be the most stringent timing constraints of any of the tasks in EID 200 because of the number of calculations that are performed every second. In the exemplary embodiment, the Energy Information Task uses approximately 500 to 600 ms of every 1000 ms process cycle. The Energy Information task does not occupy a contiguous portion of the 500 to 600 ms time, however, so that other tasks may be serviced without creating data latency problems and associated inaccuracies. In the present embodiment, it is believed that a significant and even a majority portion of time are allotted to the energy information harmonics task. This task is estimated to require approximately 90 ms per phase. In the present embodiment, the Energy Information Task is activated 4 times per second as a result of ADC signal 233 (FIG. 2C) indicating that ADC 232 A, 232 B has finished sampling a phase. To facilitate RMS computations, the system preferably uses the square root techniques of co-pending and commonly assigned case U.S. patent application Ser. No. 08/625,489, which is entitled “Fractional Precision Integer Square Root Processor And Method For Use With Electronic Circuit Breaker Systems,” and which is incorporated by reference.
[0283] The energy information code essentially consists of two parts. The Energy Information task which operates in the foreground, and OC1/IC1 interrupt service routines which operate in the background. The background code (ISRs) collect the samples for the next phase while the foreground code (meter task) manipulates the samples collected for the last sampled phase. The background code is illustrated in FIG. 13A and the foreground code is illustrated in FIGS. 13 B- 13 C.
[0284] Referring to FIG. 13A, at Step 1300 and OC1 interrupt occurs to activate the background sampling task. At Step 1302 , a command is sent to ADC 232 A, 232 B to collect a sample. At Step 1304 , ADC 232 A, 232 B collects a current and a voltage sample, respectively, for the currently sampled phase. At Step 1306 , an IC1 interrupt is generated. At Step 1308 , the current and voltage samples are stored. At Step 1310 , a determination is made as to whether the sample set is complete, i.e., have 384 samples been taken. If the sample set is complete Step 1312 is entered, otherwise the task waits for another OC1 interrupt at Step 1313 . Once 384 samples are collected, Step 1312 disables the OC1 and IC1 interrupts. At Step 1314 , the Energy Information task is activated.
[0285] Referring to FIG. 13B, the foreground Energy Information task is outlined. At Step 1316 the Energy Information task is activated when the IC1 interrupt service routine determines a complete set of phase samples has been collected. At Step 1318 , a determination is made as to which Phase was most recently sampled. If Phase N was most recently sampled the process continues at Step 1332 , otherwise Step 1320 is executed. At Step 1320 , ADC 232 A, 232 B is instructed to begin sampling the next phase. At Step 1322 , the sum of squares for the current and voltage of the most recently sampled Phase is calculated. At Step 1324 , the harmonics most recently sampled Phase is calculated. At Step 1326 , the power of the most recently sampled Phase is calculated. At Step 1328 , RAM 236 is updated with the data calculated in Steps 1322 through 1326 . At Step 1330 , the task is completed.
[0286] As mentioned above, if Step 1318 determines that the most recently sampled phase was Phase N, Step 1332 is entered. At Step 1332 , the sum of the squares of the current samples of Phase N are calculated. At Step 1334 , the harmonics of Phase N amps are calculated. At Step 1336 , the phase current for Phase N is calculated. At Step 1338 , the temperature of EID 200 is calculated. At Step 1340 , the data stored in RAM 236 at Step 1328 for each of Phase A, B, and C is read.
[0287] Referring to FIG. 13C, at Step 1342 the data read from RAM 236 at Step 1340 is used to calculate the sums and averages to generate the metered quantities for display on LCD 24 . At Step 1344 , the data is stored and becomes available for display and communication. At Step 1346 , the energy registers are cleared if necessary. At Step 1348 , the energy quantities are accumulated. At Step 1350 , the demand calculations are restarted if necessary. At Step 1352 , the demand is calculated. At Step 1354 , the min/max log is cleared if necessary. At Step 1356 , the min/max log is updated if a new min/max event occurred. At Step 1358 , event data is loaded and at Step 1360 , the Event Task is posted to run at the next available processing slot. At Step 1362 , the power data is loaded and at Step 1364 , the harmonic data is loaded. At Step 1366 , a determination is made as to whether the display is in the scroll mode. If display is in the scroll mode, Step 1370 is entered and the LCD Scroll Task is posted to run. Otherwise, Step 1368 is entered and the Display Task is posted to run. After one or the other is posted, Step 1372 is entered and the Meter Task is complete.
[0288] [0288]FIGS. 14A and 14B are flowcharts showing the LCD Scroll Task. The LCD Scroll Task (when in LCD scrolling mode) works in conjunction with the Display Task (when in fixed LCD mode) to provide information to LCD 240 . The Energy Information Task activates the LCD Scroll Task once a second when the scrolling mode is active. In the present embodiment, four fixed LCD displays have been selected for display on LCD 240 while LCD 240 is scrolling. When the LCD 240 is in the scrolling mode a display will remain on the LCD 240 for approximately seven seconds. LCD 240 will then be changed to the next display in the scrolling list.
[0289] Referring to FIG. 14A, two ways are illustrated to enter the scrolling mode. At Step 1400 , the scroll task is entered. At Step 1402 , if power on is detected Step 1404 is entered, otherwise step 1406 is entered. At Step 1404 , a determination is made if the keypad has been inactive for 10 seconds after power up. If this determination is satisfied the scrolling mode is entered at Step 1408 . At Step 1406 , a determination is made if the keypad has been inactive for 5 minutes. If this determination is satisfied, the scrolling mode is entered at Step 1408 , otherwise Step 1406 is repeated. At Step 1408 , the first scroll display is initiated. At Step 1410 , a determination is made whether the scroll display is a new display. If the display is a new display Step 1412 is entered, otherwise Step 1416 is entered. At Step 1412 the LCD 240 is cleared to prepare for the new display. At Step 1414 , the display counter is initiated. At Step 1416 , a determination is made if the EID 200 has a system error. If a system error is detected Step 1418 is entered, otherwise processing proceeds to Step 1420 in FIG. 14B. At Step 1418 , the display is updated with the system error display.
[0290] Referring now to FIG. 14B, at Step 1420 , the LCD 240 is updated with the current scroll display. At Step 1422 , the display counter is checked for a time-out. If a time-out is detected Step 1424 is entered, otherwise Step 1410 is reentered. At Step 1424 , the next scroll display is selected. At Step 1426 , the display timer is re-initiated, and Step 1410 is re-entered. During this process, a wait loop 1428 is running in the background to detect a keypad depression. When a keypad is depressed, Step 1430 is entered. At Step 1430 , the display exits the scrolling mode. At Step 1432 , the fixed display is reactivated displaying the last information prior to entry into the scroll mode. FIG. 15 is a flowchart showing the Events Task. The Events Task is activated once a second by the Energy Information Task. When activated, the Events Task maintains the states and delays for each alarm and relay function. The events task also clears the event and trip logs when requested and maintains the data written into the event and trip logs. When the Energy Information Task has completed calculating the most recent energy information data, the Energy Information Task loads the data into the Events Task. When activated, the Events Task checks the set points for each programmed alarm and relay function. When a set point is exceeded, the respective alarm or relay enters the wait state. If the delay time is exceeded, the alarm or relay function enters the active state. If an event causes several alarms to activate during a single event task, only the first alarm checked is initially entered into the event log. After the logged alarm is cleared, any other alarm that is in the active state will be logged. In this way, only one alarm at a time is logged in to prevent a single event, which may cause several alarms to become active, from overflowing the event log.
[0291] Referring to FIG. 15, the Events Task is illustrated. At Step 1500 the events task is entered. At Step 1502 , a determination is made if a Clear Trip Log request is detected. If so, Step 1504 is entered, otherwise Step 1506 is entered. At Step 1504 , the Trip Log is cleared. At Step 1506 , a determination is made if a Clear Event Log request is detected. If so Step 1508 is entered, otherwise Step 1510 is entered. At Step 1508 , the Event Log is cleared. At Step 1510 , the alarms are checked, logged in the Event Log, and activated or deactivated as required. At Step 1512 , the protective relays are checked. If necessary, relay alarm data is logged in the Event Log. Also, if necessary, relay trip data is logged in the Trip Log and the circuit breaker is tripped. At Step 1514 , the SPI message task is activated if necessary and at Step 1516 , the Events Task is complete.
[0292] [0292]FIG. 16 is a flowchart outlining the Keypad Task. In the present embodiment, the Keypad Task is activated every 250 ms to determine if a key has been pressed. If a key is available, the Display Task or LCD Scroll Task is informed so that the display can be updated as required. If a key is pressed, the scroll delay is reset to 5 minutes and, if LCD 240 is currently in the scrolling mode, the display mode is changed to fixed display mode. At Step 1600 , the Keypad Task is entered. At Step 1602 , a determination is made whether a new key depression occurred. If a new key depression is detected Step 1604 is entered, otherwise Step 1602 is reentered. At Step 1604 , the scroll delay is reset to 5 minutes. At Step 1606 , the current display mode is determined. If the mode is the scrolling display mode, then step 1608 is entered, otherwise Step 1610 is entered. At Step 1608 , the display mode is changed to the fixed display mode. At Step 1610 , appropriate flags are set for other tasks and the display Task is entered.
[0293] [0293]FIG. 17 is a flowchart outlining the Display Task. The Display Task is activated once per second when the display is in the fixed mode or on demand in response to depressing a key. Screens that contain changing data are updated every second. Screens that contain fixed information are updated only when a key is depressed. When starting at the Main Menu, lower level menus and information/set point screens are entered when the Enter Key 412 is depressed. Likewise, when starting at a lower level screen in the menu hierarchy, higher level screens are entered when the ESC key 414 is depressed. The Up key 408 and Down key 410 are used to change the values/set points of programmed data, for example. In particular, at Step 1700 , the Display Task is entered. At Step 1702 , the area of RAM 236 containing the display data is updated based on the current display and whether a key was pressed. At Step 1704 , the SPI Message Task is activated if necessary. At Step 1706 , the display RAM is copied to the LCD interface 240 A. At Step 1708 , the Display Task is completed.
[0294] [0294]FIG. 18 is a flowchart showing the RS232 Task, which determines what response needs to be transmitted after an RS232 message is received. Once the response is determined, the Transmit Message Task is activated. In the present embodiment, both the RS232 Task and the RS485 Task use the same functions to decode incoming messages and build the outgoing responses. The RS232 UART Interrupt 249 FIG. 2C receives and transmits data on the RS232 port 248 . When the last message byte is received, the RS232 UART Interrupt activates the RS232 Task so that the response to the message can be determined. Likewise, after the RS232 Task builds the response message, it activates the Transmit Message Task which causes the RS232 UART Interrupt 249 to transmit the response out the RS232 port. The RS232 Task is activated by the RS232 UART interrupt 249 after a message has been received. Again, referring to FIG. 18, the RS232 Task is illustrated. At Step 1800 , the RS232 task is entered as a result of RS232 UART interrupt 249 . At Step 1802 , the communications semaphore is acquired from the operating system (OS). At Step 1804 , the received message is processed. At Step 1806 , the SPI Message Task is activated as required. At Step 1808 , the Transmit Message Task is activated to send the response message. At Step 1810 , the communications semaphore is released to the OS.
[0295] [0295]FIG. 19 is a flowchart outlining the RS485 Task. The RS485 Task determines what response needs to be transmitted after a RS485 message is received. Once the response is determined, the Transmit Message Task is activated. As mentioned above, both the RS232 Task and the RS485 Task use the same features to decode incoming messages and build the outgoing responses. The Process RS485 Task is activated by the SCI interrupt after a message has been received. The RS485 UART Interrupt receives and transmits data on the RS485 port. When the last byte of a message is received, the RS485 UART Interrupt activates the RS485 Task so that the response to the message can be determined. Likewise, after the RS485 Task builds the response message, it activates the Transmit Message Task which causes the RS485 UART Interrupt to transmit the response out the RS485 port. In particular at Step 1900 , the RS485 task is entered as a result of an RS485 interrupt. At Step 1902 , the communications semaphore is acquired from the OS. At Step 1904 , the received message is processed. At Step 1906 , the SPI Message Task is activated as required. At Step 1908 , the Transmit Message Task is activated to send the response message. At Step 1910 , the communications semaphore is released to the OS.
[0296] [0296]FIG. 20 is a flowchart showing the Transmit Message Task. The Transmit Message Task determines what response needs to be transmitted after a message is received. The Transmit Message Task is activated by the RS232 Task and the RS485 Task after an incoming message has been decoded and a response message has been determined. This task activates the RS232 UART 248 A or RS485 transmitter 246 A if a response is required. In particular, Step 2000 , the Transmit Message Task is entered. At Step 2002 , it is determined whether an RS232 or RS485 task initiated the Transmit Message Task. If so Step 2004 is entered, otherwise the task is terminated at Step 2008 . At Step 2004 , it is determined whether a transmit message is necessary. If so Step 2006 is entered, otherwise the task is terminated at Step 2008 . At Step 2006 , the transmit message is sent. At Step 2008 , the Transmit Message Task is terminated.
[0297] [0297]FIG. 21 is a flowchart showing the SPI Message Task. The SPI Message Task handles Inter-processor communications between the Protective microprocessor 214 and Energy Information/Communications microprocessor 222 . The SPI Message Task is activated by the tasks that need to send a message to the Protective microprocessor 214 . In particular, at Step 2100 Energy Information/Communications microprocessor 222 initiates the data transfer by first pulsing SPI interrupt line 259 . At Step 2102 , Energy Information/Communications microprocessor 222 first loads 16 bytes of data into the SPI buffer and at Step 2104 , pulses the interrupt line 259 . At Step 2106 , the Protective microprocessor 212 transfers the first 16 bytes of the message from the Energy Information/Communications microprocessor 222 . At Step 2108 , Energy Information/Communications microprocessor 222 again pulses interrupt line 259 to indicate that the data transfer is complete. At Step 2110 , Energy Information/Communications microprocessor 222 loads a second 16 bytes of data into the SPI buffer and at Step 2112 , pulses interrupt line 259 . At Step 2114 , Protective microprocessor 212 transfers the second 16 bytes of data.
[0298] At Step 2116 , the 32 bytes of data are processed by the Protective microprocessor 214 . At Step 2118 , Protective microprocessor 214 sends 16 bytes of response data to Energy Information/Communications microprocessor 222 . At Step 2120 , Energy Information/Communications microprocessor 222 pulses the SPI interrupt line to suspend data transfer. At Step 2122 , Energy Information Communications microprocessor 222 stores the first 16 bytes of data and at Step 2124 , pulses SPI interrupt line 259 to continue the data transfer. At Step 2126 , Protective microprocessor 214 sends the last 16 bytes of data to Energy Information/Communications microprocessor 222 . At Step 2128 , a status message is posted to the calling task to indicate whether an error occurred during the SPI Task. At Step 2130 , the sequence is complete.
[0299] Exemplary SPI messages that the Energy Information/Communications microprocessor 222 sends to the Protective microprocessor 214 include the following: (1) EEPROM Read—read an item from the Protective microprocessor's EEPROM; (2) EEPROM Write—write an item from the Protective microprocessor's EEPROM; (3) Update Status—the Energy/Communication and Protective boards swap status information; (4) Clear Trip Log—clear trip log data in the Protective microprocessor's EEPROM; (5) New Trip Log Entry—add new trip log entry to the Protective microprocessor's PROM 216 ; (6) Breaker Test—perform a breaker test; (7) System Information—get the rating plug value and protective code version; and (8) Trip Breaker—instruct Protective board to trip circuit breaker 116 .
[0300] [0300]FIG. 22 is a flowchart showing the Error Task, which displays a predetermined error screen if a system error occurs. At Step 2200 , the error type is displayed. At Step 2202 , the task waits for the ESC key to be pressed. After the ESC key is pressed, Step 2204 is entered. At Step 2204 , Energy Information/Communications microprocessor 222 is reinitialized. In the present embodiment, if an error occurs, one of 6 high level error values will be displayed on the error screen. If the high level error was caused by an SPI error, then the SPI error value will be displayed after the high level error value separated by a dot (.). For example, if the error screen displays 1.4 as the error number, this is an indication that a EEPROM write message failed as a result of a EEPROM programming failure. Exemplary High Level Error values are: (1) EEPROM write error; (2) Status message error; (3) Clear trip log error; (4) Trip log update error; (5) Breaker test error; and (6) Breaker trip error. Exemplary Low Level SPI Error values are SPI errors reported by protective processor, which include: (1) Invalid message type received; (2) Bad LRC received; (3) Invalid length byte received; (4) An EEPROM programming failure occurred; and (5) An invalid test was requested. Exemplary SPI receive errors detected by Energy Information/Communications microprocessor 222 include: (6) Bad message type error; (7) Bad LRC error; (8) EEPROM read message error; (9) EEPROM write message error; (10) Update Status message error; (11) Clear Trip Log message error; (12) New Trip Log Entry message error; (13) Breaker Test message error; (14) System Information message error; and (15) Trip Breaker message error.
[0301] While the present invention has been described in terms of the exemplary or present embodiment, as currently contemplated, it should be understood that the present inventions are not limited to the disclosed embodiments. Accordingly, the present inventions cover various modifications comparable arrangements, methods and structures that are within the spirit and scope of the claims.
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An energy information management method for use with a circuit breaker coupled between a power source and a load, the method comprising the steps of: (a) sensing at least one of a voltage and a current flowing between the power source and the load through the circuit breaker; (b) counting a number of times the circuit breaker trips and interrupts the current flow between the power source and the load; (c) measuring the current flow through the circuit breaker when the circuit breaker trips and interrupts the current flow between the power source and the load; (d) determining a plurality of conditions of the circuit breaker; (e) accepting a user input, the user input for at least one of controlling the circuit breaker and displaying the plurality of conditions of the circuit breaker; (f) displaying at least one of the plurality of conditions of the circuit breaker responsive to the user input; and (g) communicating at least one of the plurality of conditions to a remote terminal.
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FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a music instrument, an excitation device for contact-less excitation of at least one prestressed string by a magnetizable material, as well as to a method for generating sounds.
Known music instruments can, in principle, be classified into two groups, i.e. in acoustical ones and in electric ones, particularly electronic instruments. Acoustical instruments radiate the sound or tone with sufficient loudness so that a piece performed by an acoustical instrument can be directly heard by the audience. For generating and radiating sound acoustical string instruments comprise strings, a tensioning device for the strings and a resonance body, wherein the strings are mechanically started oscillating, the string oscillations are transferred to the resonance body and are radiated by the latter. The various string instruments have each characteristic sounding properties which depend on the strings, the tensioning device, the resonance body and of the mechanical excitation. Electric or electronic instruments generate an electric or electronic signal which is supplied to a loudspeaker via an amplifier and is radiated by the loudspeaker. For playing an electric instrument, a bank of keys or keyboard is provided. The keys may release a signal either directly and/or they may excite a physical system, of which at least one parameter is tapped and transformed into an electric signal. Such a physical system may be used for detecting a characteristic of stroke. With synthesizers, there exist diverse possibilities of a signal alteration. In the case of electroguitars and electrobasses, the physical string oscillation is mechanically excited and is picked up by a cartridge (pick-up) and is fed to a loudspeaker via an electric or electronic circuit. For generating electronic sound signals, MIDI-appliances, such as a MIDI-sax, may be used. A MIDI-sax detects, apart from the grip, also the throughput of air and, optionally, a force which acts from the lips onto the mouth piece, particularly onto a reed. The parameters detected enable generating a signal which, apart from tone pitch and the duration of a tone, comprises also the dynamics of loudness and, optionally, further tone properties. The sound quality of an electric instrument will always depend on the circuitry used and the loudspeaker coupled to it.
From document FR 2 313 740, an apparatus is known in which a plurality of prestressed strings of equal length are each excited in a contact-less manner by an electromagnetic exciting element. In order to be able to start the strings oscillating by changing magnetic fields, the strings are formed of a magnetic material. The strings are arranged between two disks, the disks being kept in a predetermined distance to each other by a cylindrical base. Each exciting element is fed by a frequency so that each string is excited and vibrates at its basic frequency corresponding to its respective string tension. For feeding the exciting elements, a multivibrator having an adjustable frequency is used. In order to render the oscillation of a string audible, it is picked up by a pick-up, and the signal, thus obtained, is supplied to a loudspeaker via an amplifier. The sound generated by such an apparatus will result from the superposition of the basic oscillations of the strings. Thus, it is only a sound source rather than an instrument that can be played. In addition, the sound quality is limited by the loudspeaker.
WO 98/28732 discloses an electroguitar, that can be automatically tuned, in which the strings to be tuned are electromagnetically excited whereupon the string tension is adjusted by an automatic tensioning device. Exciting of each string is effected with the frequency of the desired basic oscillation, and the actually resulting string oscillation is picked up by a pick-up so that a signal of adjustment can be determined from the difference between the desired and picked-up frequencies. The amplitudes necessary for tuning are very small. The electromagnetic excitement device starts the strings oscillating at hardly audible oscillations by a simple electromagnet.
EP-A-0 539 232 discloses an approach for a prolonged oscillation period of a mechanically excited string of an electric string instrument. To this end, the frequency of the excited oscillation is picked by a pick-up device. The signal of the pick-up device is amplified and fed to an electromagnetic exciting device, which keeps the string further oscillating. U.S. Pat. No. 5,070,759 discloses also an approach for a prolonged oscillation period of a mechanically excited string. It is suggested to use the exciting device also as the pick-up. In both approaches, the signal used for exciting is originated from the string itself, and for generating an audible sound, the signal picked up is fed to a loudspeaker via an amplifier. The exciting devices described comprise each at least one coil and parts of magnetizable material and/or parts of a magnetic material. Each coil extends over the whole region which comprises the strings. In order to be able to excite the strings sufficiently, coils of thicker wires and elevated numbers of windings are used, as compared with a pick-up. In addition, examples are described in which the density of the magnetic field is different for differently thick and differently strongly prestressed strings. To this end, either the magnetizable material within the coil is sub-divided into different regions associated to the respective strings by slots or different permanent magnets are assigned to the strings. In these known exciting devices, the electromagnetic field used for exciting extends always over the whole region containing all strings. If a signal stems only from one string, merely a small area of the exciting field is used for exciting this string. The efficiency of this exciting device is very small, and only faint excitements can be achieved which are than acoustically radiated through an amplifier and a loudspeaker.
The acoustical as well as the electric music instruments have their respective limitations. In the case of the acoustical instruments, generating sounds is limited to an appropriate operation of the instrument by a playing person. In the case of electric instruments, a limitation is given by using the necessary loudspeaker. By the known exciting devices for exciting an oscillation of the strings by electromagnetic fields only oscillations of small amplitudes are achievable.
SUMMARY OF THE INVENTION
The invention has an object due to the limitations of known instruments, to provide an instrument which has less limitations, thus opening up new possibilities.
When solving the problem, it has been recognized that a string instrument according to the invention should combine the sound quality of an acoustic string instrument with the varied control facility of an output signal of an electric or electronic instrument or appliance, particularly of a synthesizer, keyboard, computer, MIDI-appliance microphone or also of any loudspeaker output. In the known acoustic string instruments, the strings are excited by striking, plucking or bowing, the strings being started to oscillate due to this mechanical excitement by free oscillation or resonance having corresponding proportions of overtones. The spectrum of overtones plays an important role for tone color, but cannot, or only to a restricted extent, be employed by mechanical excitement in a controlled manner. Now, if in the case of the string instrument according to the invention an advantageous contact-less excitement is used instead of a mechanical excitement of the strings, particularly with exciting frequencies within the whole audible frequency range, the spectrum of overtones of the strings can be excited in a controlled manner. Thus, signals can be used for controlling the string instrument according to the invention which excite directly overtones with selected intensity which is not possible with mechanical excitement. In acoustical instruments, when playing tones with flageolet grips, the ground color is dampened after exciting this ground tone so that the overtones become audible. When doing this, an overtone can never sound in the same quality or as a sine tone, as it is the case if it is excited directly by the instrument according to the invention. The number of overtones increases considerably towards top tones, so that in the second octave above the ground tone two overtones may be played, in the third octave four, in the fourth octave eight and in the fifth octave sixteen. Only part of these overtones correspond to a tone of a tempered tuning, i.e. in the second octave two, in the third octave three, in the fourth octave five and in the fifth octave seven. With an acoustical music instrument, the phenomenon of overtone dynamics in the sound development plays an important role which should not be the case with a loudspeaker.
An instrument according to the invention comprises at least one tunable string, a holding device for holding the at least one string, an electrically or electronically operated exciting device for contact-lessly exciting of the at least one string, a sounding body for acoustically radiating oscillations of the string, and an interface for supplying a signal to the exciting device, the signal being generated independently from the at least one string. The exciting device enables exciting string oscillations of sufficiently large amplitudes so that the sounding body is enabled to radiate tones of a loudness which is at least within the range of known acoustical string instruments, the loudness range for a high loudness preferably extending beyond the maximum loudness of known acoustical string instruments. For transferring the string oscillations onto the body, at least one transfer element, preferably a bridge, is arranged between the body and the at least one string.
The electroacoustic music instrument according to the invention has the quality of an ability of resonance and of discrete overtones, and enables a synthesis of an acoustical tonal beauty with electronic flexibility. By exciting the strings of an acoustic instrument in a contact-less manner, an effect results which is far beyond that of an electric control of a mechanical exciting device. It is not the known way of playing of an acoustical instrument which is striven for, but a new instrument is provided which overcomes the limitations of known instruments and appliances.
For holding the at least one string, a holding device is provided which, preferably, comprises two lateral parts and at least one supporting column, the supporting column being situated between the two lateral parts. The at least one string extends from one lateral part to the other and is tensionably connected with one lateral part at one end. In order to be able to achieve loud tones, it is suitable, to prestress each inserted metal string with a tensioning force within the range of 200 to 1000, particularly 300 to 700, preferably substantially 500 N. If, for example, 24 strings are provided, the holding device has to bear a tensioning force of up to 12,000 N. To avoid that a single extremely massive supporting column has to be used, optionally a plurality of tubes and/or profiles are arranged substantially side by side. In order to prevent that the holding device starts oscillating caused by the oscillating strings, thus generating undesirable noise, damping elements are assigned to the holding device. For example, at least portions of hollow signed to the holding device. For example, at least portions of hollow supporting columns may be stuffed or filled with rubber, particularly hard rubber. It has been found that the development of noise depends to a high degree on the two lateral parts. If stabilization ribs projecting towards the interior are provided on the lateral parts, they should be formed as a pair, and the interspace should be stuffed or filled with rubber, particularly hard rubber.
In order not to affect the radiation of sound by the supporting column, the resonance body is arranged between the strings and the at least one supporting column. The surface of the resonance body which faces the strings is formed by a membrane. To transfer the string oscillations to the membrane, a bridge is provided on the membrane over which the string is prestressed. The resonance body is formed separated from the holding device and is attached to it in such a manner that the oscillation possibility of the body, and particularly of its membrane, is substantially not affected by the holding device. The body can be formed by a two-dimensional membrane which, optionally, has a shape deviating from a flat surface. Preferably, a hollow body is used which comprises a casement (or frame) closed in shape, where on one of the front surface of the casement the membrane is attached, while on the other front surface a bottom is fixed. Optionally only ribs are attached to the membrane instead of a casement. It will be understood that optionally the holding device may also be formed by the body, particularly by its casement. However, the holding device, in the case of a plurality of strings, particularly strings which are prestressed with a high tensioning force, has to have a high stability which will be achieved preferably by a holding device separated from the body.
In order that the membrane has particularly good oscillation properties, it is produced from sounding timber having narrow annual rings, and is connected to the casement in pre-stressed condition. In sounding timber, the annual rings are perpendicular to the surface of the timber, the fiber direction of the sounding timber extending in a first direction of the membrane surface, while in a second, perpendicular direction of the membrane surface one annual ring follows the other. The membrane will be less flexible in the first direction than in the second one. A flat membrane, as flexible surface in unstressed condition, cannot receive oscillation, transferred to it through the bridge, in an optimum way. Therefore, it is slightly bent at least in the second direction, but preferably also in the first direction and is, thus pre-stressed, fixed to the casement. The front surface of the casement, which faces the membrane, is curved in correspondence with the desired bending of the membrane. Preferably, four parts of the casement forming a rectangle together are provided. The first direction of the membrane extends in the direction of the longer side of the rectangle. The second direction of the membrane extends in the direction of the shorter side of the rectangle. Correspondingly, the front surfaces of the shorter parts of the casement are curved more than the front surfaces of the longer parts. Thus, the membrane will have the shape of a partial surface of a torus or of a ton body, this toroidal surface protruding preferably towards the string, thus radiating under a larger spatial angle than a surface which would be bent towards the interior of the body. A body having the pre-stressed membrane, as described, ensures a particularly efficient reception and acoustical radiation of the string oscillations transferred via the bridge.
It will be understood that the parts of the casement can also be arranged to form a different polygon, for example a quadrangle without a right angle or a hexagon. The membrane will have a correspondingly different form. Differently formed bodies may also be desired either due a better radiation characteristic or due to a different design.
In order not to impede oscillation of the membrane, at least one opening is formed in the body by which an air exchange is enabled from the interior of the body to ambient. In order not to change in a negative way the stress distribution in the membrane by the opening the at least one opening is formed within the region of the casement so that the proportion of sound exiting through the opening also enters the half space adjacent to the membrane and emerges in forward direction.
If only one string is used, solely tones of the spectrum of overtones of this one string can be radiated off which form a very limited spectrum of tones particularly within the range between the ground tone and its second octave. In order to be able to play pieces, which have been written for known string instruments, with the instrument according to the invention, it is preferred to use a chromatically tuned set of strings. To this end, an individual instrument could be provided having, for example, a chromatic set of strings over two octaves. Such an individual instrument which comprises an alto octave and a bass octave would encompass, for example, strings of a tuning g to f sharp′ and contra G to F sharp. Preferably, however, register instruments having each 12 chromatically tuned strings which encompass one octave are built. The register instruments can be provided as a soprano, alto, tenor, bass or contra-bass instrument. Since the overtones of each string can be particularly well excited by the contact-less excitement up to a high pitch, one can make music even with a single register instrument, starting from the deepest tone up to very high pitches in all 12 keys. Apart from the chromatic tones of a tempered tuning, a variety of overtones is at disposal, whereby the most divers and special tone colors can be produced. In order to enable achieving a great loudness which may be excited to a maximum, optionally at least two strings are used at least for individual pitches. For example, it has been found in the case of bass strings that the achievable loudness is doubled, if two strings laid directly side-by-side and being excited by the same exciting device. In the case of high pitches, particularly of an alto level or a soprano level, it may be convenient to assign to each exciting device three equally tuned strings.
A register instrument according to the invention comprises a range of tones of 5 to 6 octaves due to the purposefully playable overtones. A bass instrument and an alto instrument together gives, therefore, about the register of a piano. In contrast to a piano, more mobility is ensured by the instrument according to the invention considering its weight and size. The register instruments can be distributed in a room whereby a multifunctional open system is at disposal in which a flexible interior design has also some importance.
An electronically operated exciting device for contact-lessly exciting the at least one string comprises preferably an electromagnet on each sides of the at least one string. The exciting devices known in the prior art and comprising an electromagnet only on one side of the string are not able to ensure the preferred high exciting forces or high accelerations of the string, at least not with a reasonable exciting power. In the case of a one-sided exciting device, the magnetic field energy cannot be used in an enough efficient way for deflecting and accelerating the string. To use the magnetic field energy efficiently for accelerating a string, a system having two coils is used, the string to be excited extending through an air gap between the two coils.
In order to enable the magnetic field of the coils to exert a force onto a string, the string has either to be traversed by a current or it comprises a magnetizable material. Onto a string, which is traversed by a current, the Biot-Savart force is acting in a magnetic field in a direction perpendicular to the magnetic field and to the string so that a deflection of the string can be expected transversely to the axis of the coils and, thus, in longitudinal direction of the air gap. If the string comprises a magnetic or magnetizable material, particularly ferromagnetic material, a deflecting force can be transferred to the string by a magnetic action of the magnetic field. From the energy density of the magnetic field with the string or from the Maxwell voltage of the system a resulting force within the non-homogenous field is obtained which acts alternately in opposite directions by the variable magnetic field. The deflection of the string is in the direction of the axis of the coils and, thus, alternately towards one of the coils and transversely to the air gap.
When the string is be traversed by a current, only a faint excitation can be achieved. The force, with which the magnetic field acts onto the traversed string, can be formulated as follows:
F=i ( {right arrow over (l)}×{right arrow over (B)} )
wherein
F: Force acting onto the string [N] i: current through the string [A] I: length of the conductor section subjected the magnetic field [m] B: magnetic flux density [T]
If the string and the vectors of the magnetic field are perpendicular to each other, the following deflection force will be obtained:
F=iIB
The necessary magnetic field is generated by two coils coupled in the same direction. No permanent magnet is required. The string is in the middle of the air gap, where an approximately homogeneous field having lines of magnetic flux in the direction of the common coil axis exists. A changing force effect is caused either by a changing magnetic field B or by a changing current i trough the string. With this principle, one should take care that no heat is produced by the current flux through the string. This would lead to expansion of the string, and the instrument would be out of tune. With a maximum of tolerable current flux through the string of i=1A, a length of the magnetic exciting device of 10 mm and a desired force effect onto the string of F=0.1N, a magnetic flux density of 10T in the air gap is necessary. This is, particularly with a required air gap of about 5 to 6 mm not realistic.
The calculation has been confirmed by experiment and a simulation. The effect of force occurring between a current traversed string and a magnetic field cannot enable a sufficient excitement of a string at reasonable expenses. The flux density of the magnetic field which can be achieved is insufficient to deflect the string in lateral direction. In addition, if the string is not perfectly centered in the air gap, an uncontrolled force will occur in the direction of the axis of the coils. This force, in the oscillating magnetic field, has a share of oscillation so that the string starts oscillating. The string, however, is also drawn towards the closer coil and, in case of a distance too small, will contact it. The reason is that the string is formed of magnetizable material. If the magnetizable material of the string has a small remanence and is of low retentivity, the attraction force described will occur independently from the momentary direction of the magnetic field.
In order to be able to generate a sufficiently large exciting force at reasonable expenses, a string is used which comprises a magnetizable material, particularly a ferromagnetic one, and is preferably formed thereof. Providing at least one permanent magnet and two coils arranged at both sides of a string, an inhomogeneous magnetic field in the region of the string and, thus, a deflection force can be achieved, as has already been mentioned above. For illustration, one may imagine that the at least one permanent magnet in the air gap and, thus, in the region of the string, creates a strong magnetic field which takes over a kind of a potential function. In order to start the string oscillating within this permanent magnetic field, the coils generate non-homogeneities in the magnetic field according to the exciting signal. The coils are wound in opposite direction and generate in the case of a current flow magnetic fields, which are opposing each other with equal poles. The non-homogeneous magnetic fields in the air gap, alternating according to the current's direction, develop corresponding forces acting onto the magnetizable material of the string. If a current flows through the coils, the magnetic field in the air gap will change. Where the field generated by a coil has the same direction as the static field, the flux density becomes stronger; on the other side of the string, the fields are opposite each other which leads to a fainter magnetic field. Due to this asymmetry, a resulting force will act onto the string.
To provide a permanent magnetic field as strong as possible, preferably two permanent magnets are used. In a first embodiment, the two permanent magnets are each located in a coil and, thus, at both sides of the air gap. However, this arrangement has the disadvantage that the permanent magnets are situated where the electromagnets have the highest flux density which, in the case of strong alternating fields of the electromagnets, may lead to demagnetization of the permanent magnets. The electromagnets and the permanent magnets create closed lines of magnetic field which are subjected to a high resistance within the air gap and around the electromagnets in air. By using magnetizable cores, particularly iron cores, which, apart from the air gap with the string, offer a closed path for the lines of magnetic field, the resistance of the magnetic fields and the proportion of air space wherein the lines of magnetic field will develop and, thus, the resistance against the magnetic field will be reduced. In addition, the permanent magnets can be inserted into the closed path of the core portion, outside the coils, whereby they are subjected to a smaller field density of the magnetic field generated by the coils. When constructing, one should take care that the field strength produced by the electromagnets is smaller at the permanent magnets than the coercive field strength of the permanent magnets so that their magnetization is not affected. The resistance for obtaining alternating magnetic fields can be still more reduced by forming the core portion from interengaging core sheets having an electric isolation, whereby the occurrence of eddy current is significantly diminished.
By superimposing the fields of the permanent magnets and the electromagnets, a non-homogeneous field will develop in the air gap comprising the string. The force effect of the non-homogeneous field onto the string may be described, starting from the Maxwell voltage, as follows:
F= ½ {right arrow over (B)}{right arrow over (H)}d{right arrow over (A)}
By integrating over a system border G encompassing the string, the force effect of the magnetic fields of the coils and the permanent magnets onto the string can be described. An estimation of the resulting force shows that it depends on the field strength of the permanent magnets and the field strength of the coils. By using permanent magnets of high magnetic flux density, the efficiency of the exciting device can substantially be increased. If it is required to achieve an amplitude of the string as large as possible by a small effective power fed to the electromagnets, permanent magnets of a quality as high as possible have to be used, such as samarium-cobalt (SmCo) magnets or neodymium-iron-boron (NdFeB) magnets. In this way, the efficiency can at least be doubled as compared with ferrite magnets. A permanent magnet to be employed with advantage should enable a high magnetic flux density and should not be sensitive against interfering fields, or should have a sufficiently high coercive field strength.
For generating an non-homogeneity in the magnetic field, it would also be conceivable to use only one coil in which case the force acting onto the string would be smaller with equal coil current. With a higher coil current, a greater local development of heat would occur. In addition, with only one coil, one could not obtain an analogous non-homogeneity at the averted side of the string as at the side of the coil. Correspondingly, the excitement towards the coil and the excitement away from the coil with equal intensity of current would be different which would provoke an asymmetric excitement by a sinus signal. Therefore, an exciting device of symmetric construction with respect to a center plane is preferred, the center plane extending through the axis of the string and perpendicular to a common axis of the coils.
An exciting device having two E-shaped core parts being interconnected at the two outer projections each through a permanent magnet and comprise each a coil at the center projection enables an extremely efficient excitement of strings. By narrowing or widening the center projection, the field strength in the air gap and the extension of the field in the direction of the string can be varied. If, for example, oscillations of a small wave length should be excited, it must be ensured that the extension of the magnetic field in the direction of the string is substantially not larger than half the wave length of that tone which has the shortest wave length that should still be possible to excite. If this desired extension of the magnetic field is smaller than the diameter of the magnets used, the magnetic field emanating from the permanent magnet may be narrowed by a narrowing the core part at the center projection to the desired extension. Since E-shaped core sheets are on the market, and since high-quality permanent magnets, such as samarium-cobalt (SmCo) magnets or neodymium-iron-boron (NdFeB) magnets, are available at low costs, the advantageous exciting devices can be produced at low expenses. It will be understood that, instead of two assembled E-shaped cores, two C-shaped cores per string could be assembled, wherein two projections assigned to each other are interconnected by a permanent magnet, while the other two projections assigned to each other are each provided with a coil. Optionally, cores having more than three projections, for example 13 or 14 projections, are assembled, in which case a permanent magnet is inserted at least between two projections assigned to each other, while between each of the other pairs of projections an air gap and a string is arranged and on each of the projections of these pairs of projections coils are arranged wound in opposite directions. In this way, the permanent magnetic field emanates for all air gaps from a common magnet, the supply of the magnetic field to the air gaps being effected through the core parts. It will be understood that the at least one common magnet could be formed as an electromagnet. Arrangements with 13 or 14 pairs of projections can be used in chromatically tuned sets of strings comprising 12 single or multiple occupied strings, if the free spaces between the strings are too small to insert the connecting portion of a core part or a permanent magnet. Optionally, such arrangements can be used in known instruments having metal strings, such as a piano.
In order to be able with an instrument having a plurality of strings to excite individual strings quickly and strongly, preferably one exciting device including two coils, at least one permanent magnet and two core parts interconnected via the at least one permanent magnet is assigned to each string, but optionally to each set of two or more equally tuned strings. It will be understood that the permanent magnetic field, whose lines of magnetic flux extend mainly through the core parts, could also be produced by a current-traversed coil arranged around at least one core part. If due to an electrically produced permanent magnetic field no permanent magnet is inserted between the core parts, optionally one core part may be sufficient. Model calculations and tests have shown that a string reacts in a sensitive manner to changes of frequency. Even small deviations of the exciting frequency from the natural frequency of the string make coupling worse to a high degree. Thereby, overtones being close to each other could be excited purposefully and individually.
Even if the instrument is constantly operated with large amplitude string oscillations, the temperature at the exterior of the coils does not increase above 50° C. This good thermal property results from that sufficiently strong exciting forces can be achieved even with small power supplied. Moreover, the system has good thermal conductors by the core parts which dissipate heat developing at the coils to the exterior.
By using closed arrangements having core parts and inserted high-grade permanent magnets, the efficiency can be raised, in comparison with approaches using ferrite magnets in the coils, by a factor of 10 to 15. An efficiency as high as possible permits starting quickly the strings oscillating with extremely strong oscillation at reasonable energy expenditure. This is necessary, if the sound of the string's oscillation has to be radiated acoustically, and in particular if the instrument according to the invention has to provide the sound of a plucked bass string. High efficiency enables a good coupling of the string oscillation to the exciting signal. In this way, both the frequency characteristic and the amplitude response curve can be controlled.
The exciting device does not only enable the initial excitement of a string's oscillation, but also controlling the course of the oscillation, particularly also a deadening of the string's oscillation. To achieve selective deadening, preferably the actual oscillation is detected, an exciting signal of opposite phase is provided to excite the string with it. Detecting the actual oscillation may either be effected by a separate pick-up, by detecting the deflection optically at the exciting device used for deadening, or through a signal detected by the exciting device. If oscillations of different frequencies should be deadened in a different fashion, measuring the amplitude should be done in dependence on frequency.
It will be understood that instead of active deadening by an exciting device, mechanical deadening can also be provided. Mechanical deadening is effected by means of muffling elements that can be moved to the string. Preferably a mechanical deadening device comprises two muffling elements for each string which can be moved to the string from opposite sides. For driving the dampers, an electro-mechanical system may, for example, be provided, by which either each individual string or all strings together can be muffled.
The electromechanical system encompasses electromotors and/or electromagnetic lifting devices, particularly lifting magnets which can be positioned.
Each exciting device is operated via the interface, a signal from outside being fed to at least one input of the interface. The interface is preferably designed in such a manner that substantially any electric or electronic signal, be it analogue, digital or even in MIDI-format, particularly signals of synthesizers, keyboards, computers or signals of micro-phone or loudspeaker outputs, can be input. In order to provide MIDI-signals appliances, such as master keyboards, MIDI-sax, MIDI-guitar or other MIDI-controller are available for various instrumental techniques. To enable a versatile conversion of different electrical signals, the interface comprises preferably, apart from at least one MIDI-input, a plurality of parallel sound inputs, particularly to be switched from analogue to digital or vice versa. In order to be able to use signals from a microphone for controlling the instrument according to the invention, at least one microphone input is provided. For example, the sound of a violin may be used for controlling purposes via a microphone input. If a signal for controlling individual strings of an instrument, having a chromatic set of strings, is provided, it is suitable to use an interface having a chromatic input. Since, in the case of strings of a long oscillation period, deadening the strings is important for a good sound quality, the interface comprises preferably a deadening input or a pedal input which, for example, is connected to at least one deadening pedal. Via the deadening input, the muffling characteristic of the mechanical dampers and, optionally, of contact-less deadening by means of the exciting devices is influenced, for example by omitting or weakening the muffling effect when pressing the pedal.
The interface, starting from the input signals, produces control signals for the exciting devices or for amplifiers of the exciting devices. In the simplest case, an input signal is directly fed to the exciting devices so that the interface has to be considered only as a signal input. If the signals, which are used via a microphone or sound inputs for controlling the instrument, are not compatible with the characteristics of the instrument, the sound quality may be optimized by using filters and by two different methods of exciting. A first method, called resonance mode, uses a common exciting signal for simultaneously controlling all exciting devices, the strings, in correspondence with their natural frequencies and spectra of overtones, responding only to those signal portions having the natural frequencies of the respective strings. A second exciting method, called tone apportion mode, assigns the tones of the signal to those strings on which these tones will sound. Correspondingly, the signal portions are each fed to the appropriate exciting devices and/or to their amplifiers.
An amplifier of an exciting device should have a high efficiency so that a power proportion as high as possible is converted into an excitement of a string, while a small power proportion is converted into heat. In order to dissipate heat developing by the stray power, normally cooling is necessary which leads to large dimensions of the amplifier. In order to improve the effective output, preferably an amplifier of class D is provided. Amplifiers of class D are based on the principle of pulse width modulation and are described by B. Schweber, Class D IC-Amps: Ready for audio prime time”, EDN magazine, Jul. 1, 1999. The input signal either switches the output in or out. The amplitude of the output signal is controlled by the pulse width. The reason for the high efficiency to be achieved resides in the binary action of the circuitry: Losses are mainly produced by power switches. In contrast, the stray power in AB amplifiers develops, among others, already by the adjustment of the operating point. The efficiency of class D amplifiers to be attained is in the range of 80 to 90%. When applied in the audio-field, special output filters are necessary for the use of these amplifiers to minimize the nonlinear distortion factor. Since the exciting device itself has already a quite high inductivity, this is not necessary in the case of the present instrument.
In order to be able to design an amplifier for controlling an exciting device, the required frequency response has to be known. For this reason, the frequency response of the system, comprising the exciting device and the string, has to be determined. Since the power requirements for an amplifier for exciting a bass string are particularly high, exciting a bass string has precisely been analyzed. The measured relative acoustic pressure shows that above a frequency of about 6 kHz no oscillation of the bass string can be determined. From a frequency of about 5 kHz on, the oscillation of the bass string is superimposed by a hum of the inducing coils. With higher frequencies, the interval between the resonances is no more precisely λ/2 which can be explained by the physical properties of a bass string, especially the fact that the nodal points are not infinitely small. The low-pass characteristic of the system in the frequency response could clearly be seen. This may be explained by the inductive charge of the exciting device. If the string to be excited is not sufficiently strongly prestressed, particularly also with low frequencies a bad transfer of the string's oscillation to the body can be observed. To achieve a good efficiency with a contact-less exciting device in a lower frequency range, the strings have to be prestressed sufficiently well.
In order to convert even high-frequency signal proportions into a sufficiently loud sound, an equalizer is preferably pre-posed to the amplifier and raises the high frequencies. A limitation of the frequency response is caused by the inertia of the string. In addition, in the case of high frequencies, half the wave length is within the range or below the extension of the exciting device or the inducer's length. With a test string oscillating at 6 kHz, λ/2=12.5 mm. Thus, with an inducer's length of 10 mm the limit of a reasonable excitement of a string is reached. Therefore, if no tones above 6 kHz can be produced, the amplifier has to show a linear characteristic only below 6 kHz. Such pulse width modulation amplifiers of class D are on the market. Therefore, a contact-less exciting device can achieve a string's oscillation at a high efficiency, thereby covering sufficiently large frequency ranges and loudness ranges.
Up to now, the composition and improvization techniques using computers had only the electronically generated sound radiated by a loudspeaker at disposal. By the instrument according to the invention, such compositions obtain a new and excellent sound effect through the natural string sound and its radiation from the wooden body.
In order to protect the instrument and/or to influence its radiation of sound, preferably an envelope is provided. The envelope is connected to the holding device and comprises at least one two-dimensional, preferably curved, directional element that may be used for limiting the portion of space into which the sound from the body is radiated off. To enable the envelope its protective function, it comprises a bottom portion at the rear of the body averted from the strings, and an adjacent wall portion surrounding the body. The at least one directional element can preferably engage the wall portion to form a lid so that the envelope surrounds the body completely. In a particularly preferred embodiment, lamellar directional elements are guided by a guiding device. The directional elements may, for example, be oriented substantially in the direction of a dominant radiation direction. Optionally, the directional elements may form deviating surfaces which extend, for example, under an angle of substantially 45° to a horizontal plane from a horizontally oriented body above this body, thus deviating the sound, that emanates from the body dominantly in vertical direction upwards, in a horizontal direction.
In the case of instruments having metal strings sufficiently strongly prestressed, an exciting device for contact-lessly exciting at least one string may advantageously be used. This means that at least one string of the known instrument may be controlled, after incorporating the exciting device, via an interface by the supplied electric or electronic signal. In this case, the string must comprise a magnetizable material. The exciting device to be used comprises two coils at both sides of an air gap for receiving the string which are arranged about a common coil axis, and a magnetic device for generating a permanent magnetic field, preferably at least one permanent magnet. The permanent magnetic field in the region of the air gap is substantially parallel to the coil axis, and the coils are wound and connected in such a manner that in a current traversed condition they generate magnetic fields of equal, opposite directed poles so that an non-homogeneous magnetic field will be achieved in the air gap which enables the string to be biased by a deflection force.
In particular, it would also be possible to build an electric instrument having a chromatic set of strings and contact-less exciting devices, the sound being radiated through pick-ups, amplifier(s) and loudspeaker(s). Certainly, the sound quality would be worse, but the exciting possibilities due to the exciting device, and particularly the possibilities of deadening described, could be advantageously used for producing sound.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described with reference to embodiments shown in the drawings in which:
FIG. 1 is a perspective view of a string instrument comprising a contact-less exciting device;
FIG. 2 a perspective view of a sounding body;
FIG. 2 a , 2 b cross-sectional views along the lines A and B of FIG. 2 ;
FIG. 2 c a detail of FIG. 2 a;
FIGS. 3 , 4 schematic illustrations of exciting devices;
FIG. 5 a a schematic illustration of the existing forces
FIG. 5 b a functional illustration of the force effect as a function of the deflection at different strength of the magnetic field;
FIG. 6 a functional illustration of the exciting effect as a function of the position of the exciting device;
FIGS. 7 a , 7 b , 7 c schematic illustrations of mechanically deadening;
FIG. 8 a schematic illustration of a contact-less deadening;
FIG. 9 a schematic illustration of an interface;
FIG. 10 a perspective representation of a of application possibilities of the instrument;
FIGS. 11 12 , 13 , 14 schematic illustrations of contact-less exciting devices;
FIG. 15 a a lateral view of the instrument;
FIGS. 15 b , 15 c , 15 d schematic front views of the instrument; and
FIGS. 16 a–d schematic illustrations of an instrument envelop.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an instrument 101 according to the invention which comprises 12 chromatically tuned strings 102 tensionably held by a holding device 103 . In a preferred embodiment, at least two directly adjacent strings or a multiple set of strings is assigned to each tone. To start the individual strings or the multiple sets of strings oscillating, an electrically or electronically operated exciting device is assigned to each string 102 or to each multiple set of strings. For holding the exciting devices, at least one support 104 having through holes 104 for the strings 102 are provide. Optionally, two supports 104 including exciting devices in different positions along the strings 102 are arranged. Since the resonance oscillations cannot be excited in the region of their nodes, different natural oscillations of the strings 102 will be excited differently well at the different positions. Moreover, the exciting devices of one support 104 may be designed in such a manner that, in comparison with the exciting devices of the other support 104 , they act over a larger length with exciting forces onto the string 102 and, thus are better adapted to excite oscillations of a greater wave length.
The holding device 103 comprises two lateral parts 105 and at least one, preferably two, in particular however three or more, supporting columns 106 connected to the two lateral parts 105 . The strings 102 are arranged between the two lateral parts 105 , a respective tensioning device being provided on one lateral part 105 for tensionable attachment. One lateral part 105 comprises a diapason plate 107 so that the string length increases in steps from a shortest string to the longest string. To be able to absorb the high tensioning force of all strings, ribs 105 a are formed at the lateral parts 105 , facing the interior and being connected to the supporting columns 106 . To prevent undesirable development of noise, the ribs 105 a are preferably formed as double-ribs having an intermediate layer of hard rubber, and at least a portion of the supporting columns are filled with hard rubber. The supports 104 together with the exciting devices are attached to the supporting columns 106 and may be a bit displaced so that the strings 102 are directed through the through holes 104 a in a substantially centered way.
For acoustically radiating the string oscillations, a sounding body 108 is provided. This body 108 is formed as a hollow body and comprises a membrane 109 , a casement 110 closed in ring form and, particularly, a bottom 111 . The membrane 109 is arranged at one front surface of the casement 110 , while the bottom 111 is at the other front surface. The membrane faces the strings 102 , the strings 102 engaging a bridge 112 which, in turn, is in contact with the membrane 109 . The sounding body 108 is fixed to the holding device 103 , particularly to the support columns 106 , by a spacing adjustment device (not shown) having rubber elements. By means of the spacing adjustment device, the stress with which the strings 102 engage the bridge 112 can optimally be adjusted.
For supplying signals to the exciting devices in the supports 104 , at least one interface 113 is provided to which the control signals can be fed through at least one input 113 a . Cables 113 b lead from the interface to the exciting devices.
To ensure a high sound quality of the instrument 101 , a new, simply constructed sounding body 108 having a pre-stressed membrane 109 has been developed. According to FIGS. 2 , 2 a , 2 b and 2 c , four parts of the casement (plinths) have been assembled to a rectangle and are connected to the bottom 111 at one front surface. The long lateral parts of the casement (plinths) 110 protrude a little outwards towards the membrane 109 . To increase the stability of the long parts of the casement 110 at the membrane 109 , longitudinal ribs 114 are fixed which project to the interior at the membrane 109 , extend parallel to the membrane 109 , but are spaced a little from it. In order to ensure that the membrane 109 has particularly good oscillation properties, it is produced from sounding timber having narrow annual rings, and is connected to the casement in pre-stressed condition. In the sounding timber, the annual rings are perpendicular to the surface, the direction of the fibers extends preferably in the direction of the large rectangle side, and in the direction of the small rectangle side one annual ring follows the other. The membrane 109 is slightly bent at least perpendicularly to the fiber direction, but preferably also along the fiber direction and, thus, is fixed to the casement 110 in a pre-stressed condition, particularly being glued to it. The parts of the casement 110 are bent at that front surface facing the membrane 109 , the front surfaces of the shorter parts of the casement 110 being more bent than the front surfaces of the longer parts of the casement 110 . The preferred bending radii depend on the timber quality and are, for a short side, below 1.2 m, particularly below 1 m, preferably substantially at 0.95 m. For a long side, the preferred bending radii are above 10 m, particularly above 12 m, preferably substantially at 14 m. In this way, the membrane 109 has the shape of a partial surface of a torus or of a ton body, this toroidal surface protruding preferably towards the string, thus radiating under a larger spatial angle than a surface which would be bent towards the interior of the body. The longitudinal ribs 114 prevent that the stress of the membrane 109 results in a deformation of the long parts of the casement 110 .
In order not to change in a negative way the stress distribution in the membrane 109 by an opening, the at least one opening 115 for the exchange of air and the radiation of sound from the interior of the body 108 is formed, according to a preferred approach, in a middle region of the long parts of the casement 110 . The opening 115 extends in form of a slot through the casement 110 and the longitudinal ribs 114 . For holding the membrane 109 even in the region of the openings 115 , a holding area 114 a is formed on the longitudinal ribs 114 which projects up to the membrane 109 .
FIG. 3 shows an exciting device 116 by which an oscillating force F may be exerted perpendicularly to the longitudinal direction of a string 117 onto the string 117 which comprises magnetizable material. On either side of the string 117 , coils 118 , and within the coils 118 permanent magnets 119 , are arranged. The two permanent magnets are equally oriented and generate a strong magnetic field in an air gap 120 with the string 117 . To start the string in this permanent magnetic field oscillating, non-homogeneities are produced in the magnetic field by the coils in correspondence with an exciting signal. The coils 118 are wound in opposite directions and are connected in such a manner that magnetic fields are generated which are each directed with equal poles one against the other. In one or other current direction, the whole magnetic field density, resulting from the coils and the permanent field, is increase towards one or other coil. The magnetic fields in the air gap which, alternate in correspondence with the current direction, act with a corresponding force onto the magnetizable material of the string 117 .
FIG. 4 shows a preferred exciting device 116 ′ wherein magnetizable core parts 121 , particularly iron cores constructed of electro-sheet material, are inserted. These core parts 121 have the shape of an E and have the outer two projections 121 a interconnected by a permanent magnet 119 each, while a coil 118 is arranged around each one of the center projections 121 b . As in FIG. 3 , the coils 118 are wound and connected in opposite directions. By narrowing or enlarging the center projection 121 b , the field strength in the air gap 120 and the extension of the field in the direction of the string may be varied. By the core parts 121 , the proportion of air, wherein the magnetic field lines develop, and, thus, the resistance against the magnetic field may be reduced. In this way, the field density can be increased in the region of the air gap 120 . The superposition of the fields of the permanent magnets and the electromagnets 119 , 118 results in the non-homogeneous magnetic field indicated in the air gap 120 . The force of the non-homogeneous field acting onto the string 117 may be determined, starting from the Maxwell voltage, by integration over a system border G encompassing the string. According to FIG. 5 a , for an estimation of the force in the direction of the common axis of the coils 118 , the system border G is sub-divided into four partial surfaces A 1 , A 2 , A 3 and A 4 , and it is supposed that the magnetic field perpendicular to the areas A 1 and A 2 has a substantially constant value of B 1 and B 2 . In perpendicular direction to the areas A 3 and A 4 , the magnetic field is imperceptibly small. In a first approximation, the forces F 1 and F 2 which act onto the partial surfaces A 1 and A 2 can be calculated as follows:
F 1 = A L 2 μ 0 ( B d1 + B E ) 2 F 2 = A L 2 μ 0 ( B d2 + B E ) 2
wherein
B d1 , B d2 are flux densities produced by the permanent magnets at the surfaces A 1 and A 2 , B E are flux densities produced by the electromagnets at A 1 and A 2 , A L is a surface, and μ 0 represents a magnetic field constant.
The resulting force is calculated for B d1 =B d2 =B d as follows:
F=F 1 −F 2 =k ( B d B E )
Thus, the exciting force increases both with the field strength of the permanent magnets and with the field strength of the electromagnets. Since B E in F 1 stems from one electromagnet 118 and in F 2 from the other, an arrangement having only one coil would result in a clearly smaller force to be achieved.
FIG. 5 b illustrates the force acting onto the string 117 as a function of the deflection in the direction of the axis of the electromagnets 118 for three different types of permanent magnets 119 which generate magnetic fields of 0.25, 0.5 and 1T in the air gap. In the center of the air gap and at a deflection of 0, the force is substantially proportional to the magnetic field of the permanent magnet.
FIG. 6 illustrates that the position of the exciting device 116 , 116 ′ and of the support 104 along the string 102 , 117 plays a decisive role. Mainly for exciting oscillations of a low frequency, it is important to have a sufficient distance from the next node, because with an increasing distance from a nodal point the available lever is longer so that with an equal force the deflection is wider. For the capability of being excited represented in y direction as a function of the relative position of the exciting device along a freely oscillating string, i.e. between the one lateral part 105 and the bridge 112 , the lowest fourth partial oscillations have been taken into account. The exciting capability has an absolute maximum at a position x/l=0.83. This means that an optimum excitement of the lowest four partial frequencies is possible at this place. If higher natural frequencies of a string are encompassed by the calculation, the maximum shifts towards a position x/l=0.87. Thus, the strings may be excited in an optimum way either near the bridge or near the opposite lateral part.
Since the strings 102 , due to the high tensioning forces, hum for a long time, they have to be able to be deadened. FIGS. 7 a and 7 b show schematically two approaches for mechanically deadening a string 102 . Mechanical deadening is effected by means of two dampers 122 which approach the string from two sides. According to FIG. 7 a , the dampers 122 are moved about a point of rotation 123 each at one side of this point of rotation to the string 102 and away. According to FIG. 7 b , the dampers are moved towards each other, the string being able to be clamped between the dampers.
An electromechanical system serves for driving the movement of the dampers, the system being able to deaden both each string individually and all strings together. The manner of deadening, particularly the minimum distance of the dampers 122 from the string 102 is, for example, adjusted by a pedal or by any other control device. According to FIG. 7 c , each damper can assume a position and exert a positioning movement in a range between a maximum deadening pressure onto the string + and the complete release of the string −. The actual position and/or a stroke of movement for deadening can be adjusted by the pedal. It is possible to exceed flexibly the zero point given by the pedal, particularly up to the maximum deadening pressure. In this way, violently oscillating strings may be deadened in an ideal fashion even when deadening is faint due to the position of the pedal.
The mechanical dampers comprise per string a deadening sole with a deadening shoe as well as an adjustment device for orienting the deadening shoe along the string and transversely thereto. Actuation of the dampers is effected by mechanical lifting devices having electromotors or electromagnets. To render deadening reproducible, the drive systems have to have a position control. Zero point adjustment is either effected by positioning the magnet systems synchronously or by a separate drive system.
FIG. 8 shows a deadening approach in which the oscillation of the strings 102 is detected individually and by exciting the strings 102 in opposite phase by an exciting device 116 ′ in accordance with the string oscillation detected. To this end, the movement of the string is detected by a position measuring device 124 , for example an optical distance measurement, but optionally by measuring at the exciting device, for example by measuring induction. From measuring the position, a velocity signal may be derived which may be used for generating a deadening force. The position or the movement of the string should be measured close to the exciting device or the deadening device, if possible.
For controlling contact-less deadening, preferably a control loop is used which predetermines the amplitude course of the string oscillation during the deadening procedure through a nominal function. By measuring the amplitude, the procedure of dying out may be monitored and, if necessary due to deviations, can be influenced. The measurement of amplitudes has to be insensitive with respect to lateral oscillations so that undesirable movements are not excited by the deadening procedure. If the amplitude measurement is done in a frequency selective manner, deadening may be carrier out in a frequency selective manner too. By contact-less deadening, willful canceling of a signal spectrum is possible. This function is not possible with a mechanical damper. For deadening in an optimum fashion, the transferred force should act onto an area with maximum amplitude.
FIG. 9 illustrates an embodiment of an interface 113 having various inputs. Apart from at least one MIDI-input 125 , a plurality of parallel sound inputs 126 are provided which are, in particular, switchable from analogue 126 a to digital 126 b and vice-versa. Preferably, at least one microphone input 127 is provided. For example, the sound of a violin may be used via a microphone input. If there is a chromatic signal for controlling the individual strings of an instrument having a chromatic set of strings, it is convenient to use an interface having a chromatic input 128 which results in an ideal assignment of the tones and, in particular does not lead to tone blending. Since with strings 102 having a long oscillation period deadening of the strings is also important for a good sound quality, the interface 133 comprises in particular a deadening input 129 which is, for example, connected to a deadening pedal. By the deadening input, the deadening characteristic of mechanical dampers and/or deadening by means of exciting devices are influenced, for example releasing or weakening the deadening action when the pedal is pressed.
The interface, starting from the input signals, produces control signals for the exciting devices 116 , 116 ′ and for amplifiers 130 of the exciting devices. For an instrument having 12 strings, 12 exciting devices 116 ′ and 12 amplifiers are used. The amplifiers 130 may either be considered as parts of the exciting devices 116 ′ or as parts of the interface 113 . The signals which reach the interface via the MIDI input 125 may comprise various information, the interface 113 including various elements for converting this information. For providing control signals for mechanical deadening 131 , a first deadening controller 132 is provided to which signals from the deadening input 129 and from the MIDI input 125 may be supplied. For controlling contact-less deadening, a second deadening controller 133 is provided which processes signals from the position measuring device 124 , from the deadening input 129 and from the MIDI input 125 and enables supplying the amplifiers 130 with control signals.
Since the signals which are used via the microphone or sound inputs 127 , 126 for controlling the instrument will not be focused to the characteristics of the instrument, the sound quality may be enabled by two different exciting modes using a first and a second filter 134 or 135 . A first exciting mode, called resonance mode, uses a common exciting signal of the first filter 134 for simultaneously controlling all amplifiers 130 , where the strings 102 , in correspondence with their natural frequency and overtone spectra, will response only to signal portions corresponding to the natural frequency of the respective string 102 . A second exciting mode, called tone apportion mode, assigns the tones of one signal to those strings 102 on which these tones will sound. Correspondingly, signal portions, starting from the second filter 135 , are fed via a tone apportion element 136 to the respective amplifiers 130 . If the initial signal stems from the microphone input, it will be changed before the second filter 135 , preferably processed by a tone analysis element 137 , and in particular the signals for the deadening controllers 132 , 133 will be derived from this signal and supplied to them. Furthermore, connections are provided which permit influencing and controlling the filters 134 , 135 and the tone apportion element 136 by the MIDI input. The signals of the chromatic input 128 are substantially directly supplied to the corresponding amplifiers.
FIG. 10 illustrates the various application possibilities of an instrument 101 according to the invention that may be used in an upright position or, optionally, in a horizontal position. In each case, the instrument stands on feet 146 . To protect the instrument 101 and/or to influence the sound radiation, preferably an envelope 138 is provided. The envelope 138 is connected to the holding device 106 and comprises at least three two-dimensional, preferably curved, lamellar directional elements 139 that may be used for limiting the portion of space into which the sound from the body 109 is radiated off. To enable the envelope 138 to have a protective function, it comprises a bottom portion 140 at the rear of the sounding body averted from the strings, and an adjacent wall portion 141 surrounding the body. The directional elements 139 can engage the wall portion 141 as a lid so that the envelope 138 surrounds the sounding body 109 completely. The directional elements 139 are guided by a guiding device (not shown) having hinges for a radial movement and parallelograms for a proportional longitudinal displacement. The directional elements may, for example, form deviating surfaces which, for example with a horizontally oriented sounding body, extend under an angle of substantially 45° to a horizontal plane above the body, as to deviate the sound of the body, which dominantly exits vertically in upward direction, into a substantially horizontal direction.
For playing the instrument and for providing control signals for the instrument, appliances, such as a keyboard 142 , a microphone 143 , a synthesizer having a keyboard 144 or any audio-terminal 145 having a signal output, for example a loudspeaker output, may be used. The instrument may be played like a keyboard instrument. However, it may also be possible to use a microphone recording of a customary instrument for controlling purposes. If the instrument receives the signals of an audio-terminal or of a sequencer, it may be used as an automatic home instrument.
With a string instrument according to the invention, strings may be started oscillating by various contact-less exciting devices. FIG. 11 shows an electromagnetic exciting device comprising two hard magnets 11 and 12 that are spaced from one another by some millimeters and are surrounded each by an electromagnet 13 and 14 . Through the space between the magnets 11 and 12 , a set of one or more strings 15 is drawn. The two hard magnets 11 , 12 have to be arranged so that north pole points to south pole. The winding direction of the electromagnets 13 , 14 , in contrast, has to run one against the other (e.g. north pole to north pole).
FIG. 12 shows en exciting device having two soft magnets 21 and 22 that are spaced from one another by some millimeters and are surrounded each by an electromagnet 23 and 24 . Through the space between the magnets 21 and 22 , a set of one or more strings 26 is drawn. The string 26 is traversed by a constant current. The current has to be chosen so that no thermal effects come to fruition within the string. The current provokes a magnetic field around the string 26 . The magnetic fields of the electromagnets 23 , 24 and the magnetic field of the string will result in a force acting on the string 26 which causes oscillation.
FIG. 13 illustrates an exciting device which achieves a force effect by a modulated electrostatic field and by means of a plate arranged along the string. In addition, a modulating voltage is fed either to the string or to the plate.
FIG. 14 shows an exciting device comprising a two-plates arrangement which achieves a force effect by a modulated electrostatic field and by two plates (+U=/+1000V and −U=/this way one can make music in all 12 keys; on the 2. partial tone of a string, the first octave may be developed, on the fourth partial tone the double-octave and so forth.
The string instrument according to the invention may consist of an individual instrument or of a plurality of register instruments. An individual instrument needs a set of strings of two chromatic octaves (alto octave, e.g. g to f sharp′, and bass octave, counter G to F sharp) to attain a gamut according to standards (in addition to the 2 nd , fourth etc. partial tones). A register instrument has to have a set of strings of a chromatic octave (12 strings). Two register instruments (alto and bass) will also attain a gamut according to standards, like-wise in addition to the 2 nd , fourth etc. partial tones. A quartet of four or a quintet of five register instruments (soprano, alto, tenor, bass and contra-bass) may be played to a higher degree in ground tones by splitting the gamut.
The design of the register instrument according to the invention ( FIG. 15 a ) separates the sounding parts, the static parts and the protective parts. Above a sounding body 51 held by transfer parts 52 of an outer construction, the strings 53 are pre-stressed over a bridge 54 . The stress of the strings is held by an enveloping frame comprising two lateral portions 55 which are born by a central support column 57 and biased by a counter-force by means of two back pull elements 56 . The envelope 58 is used both as a protection and as a bell mouth or may be separated from the actual instrument (sounding body and enveloping frame).
The design of the register instrument according to the invention enables playing in a horizontal position (lying flat as a piano) as well as in a vertical position (upright like the register of a church organ). The instrument can be turned in either position about its main axis ( FIGS. 15 c , 15 d ). This is very convenient in a horizontal position in order to render the radiation angle either to the playing person or to the audience selectable.
The protective envelope according to the invention ( FIG. 16 a , a horizontal cross-section of the upright instrument) consists of a back element R and of two movable wings F 1 and F 2 . The two wings are provided with hinges at the rear Sh and in the middle Sm and are, thus, movable. By a number of lamellae, which may be shifted one above the other, the wings F 1 , F 2 may be shortened or prolonged ( FIG. 16 c ). These lamellae can be pivoted outwards and opened so that a sound radiation is possible through the protective envelope ( FIG. 16 b ).
The two wings F 1 and F 2 of the register instrument according to the invention can be arranged and modified as follows:
Instrument upright: closed condition ( FIG. 16 a ; horizontal cross-section) Instrument upright: Lamellae pivoted outwards, opened ( FIG. 16 b ; horizontal cross-section). Instrument upright: both wings are opened as a bell mouth towards a concert hall ( FIG. 16 c ; horizontal cross-section). Instrument lying flat: the first wing F 1 is disassembled into parts H and V, and is laterally mounted (as a casing), while the whole second wing F 2 is used as a lid and bell mouth H and V, and the middle hinge is arrested ( FIG. 16 d).
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An innovative music instrument ( 101 ) comprises at least one tunable string ( 102 ), a holding device ( 106 ) for holding the at least one string ( 102 ), an electrically or electronically operated exciting device ( 116,116 ′) for contactlessly exciting of the at least one string ( 102 ), a sounding body ( 108 ) for acoustically radiating oscillations of the string and an interface ( 113 ) for supplying a signal to the exciting device ( 116, 116 ′), wherein the signal is produced independently from the at least one string ( 102 ). The exciting device ( 116, 116 ′) enables exciting oscillations of the string of a sufficiently large amplitude so that the sounding body ( 108 ) can radiate tones of a loudness which is at least in the range of known acoustical string instruments. For transferring the string's oscillations to the sounding body ( 108 ), a bridge ( 112 ) is arranged between the sounding body ( 108 ) and the at least one string ( 102 ) . The electro-acoustical music instrument ( 101 ) has the quality of resonance capability and of discrete overtones, and enables a synthesis of an acoustical sounding beauty with electronic flexibility.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims priority to International Patent Application No. PCT/KR2010/002218, filed Apr. 9, 2010, entitled “Mg—Ti—Al Composite Metal Hydroxide Having a Laminated Structure, And A Production method Therefor”, which claims priority to Korean Patent Application No. 10-2010-0032353, filed on Apr. 8, 2010, the entire disclosures of both of which are hereby incorporated by reference in their entireties.
FIELD
[0002] The present invention relates to a novel Mg—Ti—Al composite metal hydroxide having a laminated structure and a method for synthesis thereof, and more particularly, to a Mg—Ti—Al composite metal hydroxide.
BACKGROUND
[0003] With development of advanced synthetic chemical technologies, polymer materials are broadly used in medical products including textiles and other various commonly used products such as a flame-retardant agent, etc. However, among polymer materials commercially available in the art, in particular, polyolefin resin, halogenated resin and polyimide resin are unstable with respect to heat or light and, in a case where they are molten through heating or used at a high temperature during a molding process, thermal degradation or quality deterioration may be caused. Due to this, a final product may encounter disadvantages such as coloring problems, modification of characteristics, deterioration in mechanical properties, or the like.
[0004] Accordingly, in order to endow heat resistant stability to the resin formed product, heavy me al fatty acids such as Pb, Cd, etc., Sn materials and/or Ba materials have been used alone or in combination with two or more thereof. However, since the toxicity of such a stabilizer has recently become a social and/or environmental problem, Sn-based and Ca—Zn based stabilizing agents are being intensively developed. However, such stabilizing agents also entail problems, for example, toxicity problems. In order to improve the above problems, some have proposed techniques using a composite metal hydroxide such as Mg—Al hydrotalcite, Li—Al hydrotalcite, etc.
[0005] Hydrotalcite is a natural mineral discovered in 1842 and was reproduced by synthesis in a laboratory by Feiknecht in 1930 which is 100 years after a general structure thereof was disclosed. A layered composite metal hydroxide, known as a layered double hydroxide (LDH) or layered mixture metal hydroxide, including an anionic layer, is a two-dimensional layered structure enabling a charge balance by using anions, which are exchangeable with a positively charged ionic layer including two kinds of cations, wherein the anionic layer and can be exchanged with a variety of organic/inorganic ions.
[0006] Such a layered composite metal hydroxide is commercially synthesized with a high purity and applied to a wide range of applications, for example, an environmental pollution remover, a catalyst inactivating agent, an acid scavenger, an acid adsorbent, a flame retardant, a flame-retardant assistant, a heat-resistant stability enhancer for polymers, an acid-neutralizing agent, a UV ray protector, a heat preservation agent, and so forth.
[0007] Preparation of the layered composite metal hydroxide may be generally classified into co-precipitation using an aqueous metal salt and hydrothermal synthesis using a poor water-soluble metal hydrate to conduct synthesis at a high temperature.
[0008] U.S. Pat. No. 3,879,523 discloses a method for synthesis of a layered composite metal hydroxide having a hydrotalcite structure by using a variety of mixed metal components and anion providing materials, which is a process to synthesize the above material through co-precipitation using a water soluble metal salt, thus requiring excess washing water in a reaction process and causing a problem of generating by-products in large quantities.
[0009] Meanwhile, U.S. Pat. No. 4,458,026 discloses a method for synthesis of a hydrotalcite type catalyst, which includes: adding a solution containing a bivalent metal inorganic salt such as magnesium nitrate and a trivalent metal inorganic salt such as aluminum nitrate mixed together to another solution containing sodium hydroxide and sodium carbonate, as an anion providing material, combined in a stoichiometric ratio thereof; reacting the mixture to synthesize a hydrotalcite slurry; thereafter, filtering and washing the slurry, and heating and drying the same at a temperature of about 300 to 600° C. The method described in the above US patent has a problem of consuming a considerable amount of heat during processing.
[0010] Alternatively, U.S. Pat. No. 4,904,457 discloses a method for synthesis of hydrotalcite at a high yield of 75% or more, which includes: heating a magnesium compound such as magnesium carbonate or magnesium hydroxide at a high temperature to activate the same; and reacting the activated magnesium in a solution containing hydroxyl group ions as well as an aluminum salt and a carbonate salt in a pH range of more than 13. However, the process proposed in the above US Patent not only consumes excess energy but also requires a reaction under an alkaline compound condition, thus causing a significant decrease in a thermal stability efficiency of the finally produced hydrotalcite.
[0011] Meanwhile, Korean Patent Laid-Open No. 2001-0108920 discloses a method for synthesis of a layered composite metal hydroxide in a hydrotalcite form, which includes: dispersing a crystalline metal hydroxide mixture in water; mixing the dispersion with a water-soluble metal hydroxide mixture, an interlayer anion providing material and a solution containing alkali-metal hydroxide; thereafter, synthesizing a hydrotalcite type layered composite hydroxide under high temperature/high pressure conditions. Although the above Korean published Patent describes that using advantages/disadvantage of both co-precipitation and hydrothermal synthesis can control physical/chemical properties of the layered composite metal hydroxide after final production thereof, a water-soluble metal hydroxide in excess is used and causes by-products in large quantities and a reaction at a high pH, thus causing disadvantages such as water pollution and requirement of excessive washing.
[0012] Alternatively, Korean Patent Laid-Open No. 2000-0049194 discloses a method for synthesis of a composite metal hydroxide containing lithium metal as a stabilizer for a halogen-containing resin. However, since three different metals as well as lithium as an expensive metal are used, economical effects are decreased.
[0013] In addition, when a Mg—Al laminated structure includes other impurities, crystallinity is generally reduced to cause a deterioration in performance (see Microporous and Mesoporous Materials 111 (2008) pp. 12-17).
SUMMARY
[0014] Accordingly, the present invention has been proposed to overcome conventional problems as described above, and an object of the present invention is to provide a metal composite hydroxide and a production method thereof, which includes: ultrasound processing to inhibit initial coloring as well as deterioration when added to a polymer, thereby providing excellent heat resistance and transparency, and superior performance of capturing any inorganic/organic compounds, especially, halogen in a solution. Raw materials used herein have economic merits and allow a metal composite hydroxide capable of solving environmental problems such as water pollution, as well as a method for production of the above material.
[0015] The above objects and other objects and/or characteristics of the present invention will be successfully achieved according to the following description.
[0016] The invention relates to a preparation method thereof which includes an ultrasound process of a solution containing a magnesium salt and a titanium salt in relative ratios of metal elements comprised in the above Mg—Ti—Al composite hydroxide, thereby giving advantageous effects such as excellent crystallinity and, when added to a polymer, prevention of degradation and early-staining properties while transparency thereof is outstanding:
[0000] Mg a Ti b Al c (OH) d (A 1 n− ) e (A 2 m− ) f xH 2 O Formula 1:
[0000] wherein A 1 n− and A 1 m− are respectively anions having valences of n and m, a/c ranges from 1 to 5, and b, c, d and x are numbers satisfying the conditions of 0<b<5, 0<c<5, 0<d and 0≦x<5, while e and f are numbers satisfying the condition of 1≦ne+mf≦5. In order to accomplish the foregoing objects, the present invention provides a Mg—Ti—Al composite metal hydroxide represented by Formula 1 below:
[0000] Mg a Ti b Al c (OH) d (A 1 n− ) e (A 2 m− ) f xH 2 O Formula 1
[0017] wherein A 1 n− and A 2 m− are respectively anions having valences of n and m, a/c ranges from 1 to 5, and b, c, d and x are numbers satisfying the conditions of 0<b≦5, 0<c≦5, 0<d and 0≦x<5, while e and f are numbers satisfying the condition of 1≦ne+mf≦5.
[0018] Also, the present invention — provides a method for preparation of a Mg—Ti—Al composite metal hydroxide having a laminated structure represented by Formula 1, including: (a) subjecting a mixed solution of a magnesium salt and a titanium salt in a solvent to ultrasonic processing; (b) preparing a solution mixture of an aluminum salt, a pH regulator and an anionic solution; (c) adding the mixed solution of step (a) to the solution mixture of step (b) and reacting a mixture thereof under high temperature/high pressure conditions; (d) filtering and washing a slurry obtained from step (c) to remove the solvent, dispersing the same in water and adding the anionic solution thereto to conduct a reaction; (e) filtering and washing a product resulting from step (d) and conducting surface treatment thereof; and (f) filtering, washing and drying a resultant product of step (e) to provide particles.
[0019] Novel Mg—Ti—Al composite metal hydroxide particles according to the present invention may capture a trace amount of halogen contained in different resins and exhibit excellent effects to inhibit deterioration and initial coloring, transparency, or the like. In addition, the Mg—Ti—Al composite metal hydroxide particles according to the present invention are not originally dissolved, instead, may maximally function to capture an anionic organic/inorganic compound, as a powder form or a molded product, from the solution.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0021] FIG. 1 is a flow chart schematically illustrating a process of synthesizing a Mg—Ti—Al composite metal hydroxide having a laminated structure according to the present invention;
[0022] FIG. 2 is X-ray diffraction analysis graphs of the composite metal hydroxides, each having a laminated structure, according to Example 1, and Comparative Examples 1 and 2, respectively;
[0023] FIG. 3 is graphs illustrating measured results of heat resistance of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Comparative Examples 1, 2, and 3 and Examples 1 and 2, respectively;
[0024] FIG. 4 is graphs illustrating measured results of heat resistance of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Examples 3, 4, 5, 6 and 7, respectively;
[0025] FIG. 5 is graphs illustrating measured results of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Examples 8, 9, 10, 11 and 12, respectively;
[0026] FIG. 6 is graphs illustrating assessment results of press characteristics of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Comparative Examples 1, 2 and 3, and Example 1, respectively;
[0027] FIG. 7 is graphs illustrating assessment results of press characteristics of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Examples 1, 2, 3 and 4, respectively;
[0028] FIG. 8 is graphs illustrating assessment results of press characteristics of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Examples 5, 6, 7 and 8, respectively; and
[0029] FIG. 9 is graphs illustrating assessment results of press characteristics of respective polymers of the composite metal hydroxides, each having a laminated structure, according to Examples 9, 10, 11 and 12, respectively.
DETAILED DESCRIPTION
[0030] As described above by the present inventors, if individual raw materials are mixed and subjected to ultrasonic processing under predetermined conditions, synthesis of Mg—Ti—Al composite metal hydroxide particles having a laminated structure represented by Formula 1 below may be possible:
[0000] Mg a Ti b Al c (OH) d (A 1 n− ) e (A 2 m− ) f xH 2 O Formula 1
[0031] wherein A 1 n− and A 2 m− are respectively anions having valances of n and m, a/c ranges from 1 to 5, and b, c, d and x are numbers satisfying the conditions of 0<b≦5, 0<c≦5, 0<d and 0≦x<5, while e and f are numbers satisfying the condition of 1≦ne+mf≦5.
[0032] In the above Formula 1, A 1 n− and A 2 m− are at least one selected from a group consisting of F, Cl − , Br − , NO 3 − , OH − , CO 3 2− , HPO 4 2− , HPO 3 2− , PO 3 3− , SO 4 2− , SO 3 2− , S 2 O 3 − , H 2 BO 3 − , SiO 3 2− , HSiO 3− , HSi 2 O 5 − , Si 2 O 5 2− , CrO 4 2− and Cr 2 O 7 2− . A 1 n− is preferably a silicic acid ion including SiO 3 2− , HSiO 3− , Si 2 O 5 2− or HSi 2 O 5 − , while A 2 m− may be CO 3 2− , SO 4 2− , NO 3− , Cl − or OH − .
[0033] The method of preparing the Mg—Ti—Al composite metal hydroxide represented by Formula 1 is characterized by including: (a) subjecting a mixed solution of a magnesium salt and a titanium salt in a solvent to ultrasonic processing; (b) preparing a solution mixture of an aluminum salt, a pH regulator and an anionic solution; (c) adding the mixed solution of step (a) to the solution mixture of step (b) and reacting a mixture thereof under high temperature/high pressure conditions; (d) filtering and washing a slurry obtained from step (c) to remove the solvent, dispersing the same in water and adding the anionic solution thereto to conduct a reaction; (e) filtering and washing a product resulting from step (d) and conducting surface treatment thereof; and (f) filtering, washing and drying a resultant product of step (e) to provide particles.
[0034] In steps (d), (e) and (f), filtering and washing may be repeatedly carried our several times, or an additional filtering-washing-filtering process may be further executed after the surface treatment in step (e).
[0035] More particularly, as shown in FIG. 1 , the inventive method of preparing the Mg—Ti—Al composite metal hydroxide may include: (a1) mixing a magnesium salt source and a titanium salt source with a solvent to synthesize a mixed solution; (a2) subjecting the mixed solution to ultrasonic processing; (a3) mixing an aluminum salt source with a pH regulator and heating the same to synthesize a solution containing the aluminum salt dissolved therein; (a4) adding an anion solution to the solution in heated state of step (a3) to synthesize a solution mixture; (a5) adding the solution of step (a2) to the solution in heated state of step (a4) to synthesize a solution mixture; (a6) reacting the solution of step (a5) under high temperature/high pressure conditions; (a7) filtering and washing a slurry resulting from step (a6) to remove the solvent, dispersing the slurry in water, and adding an anionic solution thereto, in order to conduct a reaction; (a8) filtering and washing the resultant product of step (a7) to remove the solvent and conducting surface treatment thereof; and (a9) repeatedly filtering and washing the above solution to remove the solvent and drying a resultant product to provide Mg—Ti—Al composite metal hydroxide particles having a laminated structure and being represented by Formula 1.
[0036] After the solution, containing a magnesium salt and a titanium salt in relative ratios of metal elements comprised in desired Mg—Ti—Al composite metal hydroxide particles, is subjected to ultrasonic processing, the processed solution is mixed with a solution mixture including an aluminum salt, a pH regulator and an anionic solution, and then reacted at a temperature of 150 to 220° C. and a pressure of 5 to 15 kg·f/cm 2 , that is, under high temperature/high pressure conditions, for 1 to 8 hours to synthesize Mg—Ti—Al composite metal hydroxide particles, followed by filtering, washing, surface treating and drying the particles, thereby giving a Mg—Ti—Al composite metal hydroxide powder.
[0037] Hereinafter, synthesis of the Mg—Ti—Al composite metal hydroxide according to the present invention will be described in detail.
[0038] Ultrasonic Processing of Magnesium Salt/titanium Salt Mixed Solution
[0039] After mixing the magnesium salt with the titanium salt, the mixture is subjected to ultrasonic processing. This is an important means in synthesizing Mg—Ti—Al composite metal hydroxide particles. When ultrasonic irradiation is applied to a liquid, ultrasonic cavitation occurs. Such ultrasonic cavitation is substantially associated with formation, growth and implosive collapse of bubbles. Also, the ultrasonic cavitation may lead to different physical and/or chemical influences such as a high temperature (>5000 K), a high pressure (>20 MPa), a rapid cooling rate (>1010 Ks −1 ), and the like. Therefore, it may provide specific environments in which a chemical reaction is executed under very extreme conditions. For the ultrasonic processing, it is preferable to establish an ultrasonic frequency in a range of 10 to 50 kHz, a power in a range of 100 to 1500 W, and a temperature of not more than 100° C. In addition, a time for the ultrasonic processing may range from 1 to 10 hours, and preferably, 2 to 4 hours. If the ultrasonic processing is conducted for less than 1 hour, irregular ultrasonic cavitation may occur. On the other hand, when the time for the ultrasonic processing exceeds 10 hours, magnesium and titanium hydroxides are respectively generated to cause an agglomeration of particles and, in turn, a rapid increase in a size of the particles. Accordingly, in order to uniformly generate and align the particles, the ultrasonic processing is preferably conducted for 1 to 10 hours.
[0040] The magnesium salt referred herein may include at least one selected from a group consisting of, for example, magnesium hydroxide, magnesium acetate, magnesium bromide, magnesium carbonate, magnesium chloride, magnesium fluoride, magnesium nitrate, magnesium perchlorate, magnesium phosphate, or magnesium sulfate, which are used alone or in combination with two or more thereof, but not be limited thereto.
[0041] The titanium salt referred herein may include at least one selected from, for example, titanium(IV) n-butoxide, titanium tetrachloride, titanium(IV) ethoxide, titanium(IV) isopropoxide, titanium(IV) sulfate, titanium(IV) propoxide or titanium hydroxide, which are used alone or in combination with two or more thereof, but not be limited thereto.
[0042] The solvent for synthesizing a solution mixture may be used without water or may be an alcohol-based organic solvent which has a high boiling point thus is desirably used without a loss of solution, even in a reaction at a high temperature. Such an alcohol-based organic solvent may include bivalent, trivalent or polyvalent aliphatic alcohols, for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, 3-methyl-3-methoxy butanol, tridecyl alcohol, pentanol, ethyleneglycol, polyethyleneglycol, dipropyleneglycol, hexyleneglycol, butyleneglycol, sucrose, sorbitol, glycerin, and so forth.
[0043] Preparation of Solution Mixture Including Aluminum Salt, pH Regulator and Anionic Solution
[0044] The aluminum salt referred herein may include, for example, aluminum hydroxide, aluminum acetate, aluminum chloride, aluminum fluoride, aluminum isopropoxide, aluminum nitrate, aluminum phosphate, aluminum sulfate, etc., which are used alone or in combination with two or more thereof, but not be limited thereto.
[0045] The pH regulator referred herein may include an acidic solution and an alkaline solution, which is preferably used to regulate to a pH value of 7 to 11, more preferably, to a pH value of 8 to 10. The acidic solution. is preferably nitric acid or hydrochloric acid, while the alkaline solution may include, for example, ammonia water, sodium hydroxide, calcium hydroxide, etc. The pH regulator may be the acidic solution, the alkaline solution, or a mixture of the acidic solution and the alkaline solution, wherein the acidic solution and the alkaline solution may be used alone or in combination with two kinds or more thereof.
[0046] The interlayer anionic material is an anionic component to form both upper and lower faces between a mixed metal component in the Mg—Ti—Al composite particle represented by Formula 1 below, and may include, for example, F − , Cl − , Br − , NO 3 − , CO 3 2− , HPO 4 2− , HPO 3 2− , PO 3 3− , SO 4 2− , SO 3 2− , S 2 O 3 − , H 2 BO 3 − , SiO 3 2− , HSi 2 O 5 − , Si 2 O 5 2− , CrO 4 2− , Cr 2 O 7 2− , or the like. Particular examples of a silicon compound, a boron compound and/or an aluminum compound may include sodium meta-silicate, sodium ortho-silicate, sodium silicate such as water glass No. 1, 2 or 3, lithium silicate, potassium meta-silicate, potassium ortho-silicate, sodium tetraborate, sodium meta-borate, sodium ortho-aluminate, calcium ortho-aluminate, sodium meta-aluminate, potassium meta-aluminate, aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum phosphate, or the like. The interlayer anion may be used alone or in combination with two kinds or more thereof. Among the anionic solution described above, cations responding to the anion may include, for example, hydrogen ion, alkali-metal ions such as Na +, K + , etc., and alkali-earth metal ions such as Mg 2+ , Ca 2+ , etc., however, not being limited thereto.
[0047] High Temperature/High Pressure Reaction
[0048] To a solution mixture of an aluminum salt, a pH regulator and an anionic solution, a mixed solution of magnesium/titanium is added, followed by proceeding a reaction at a temperature of 120 to 250° C. at a pressure of 2 to 20 kg·f/cm 2 , for 1 to 24 hours. Preferably, the reaction is conducted for 2 to 8 hours. If the reaction temperature is less than 120° C. and the pressure is less than 2 kg·f/cm 2 , Mg—Ti—Al composite metal hydroxide particles is slowly proceeded to thus increase a reaction time. On the other hand, when the reaction temperature is more than 250° C. and the pressure is more than 20 kg·f/cm 2 , Mg—Ti—Al composite metal hydroxide particles have reduced particle size and become micro-particles, hence causing agglomeration of particles and requiring high-cost equipment for mass production of products.
[0049] Filtering, Washing and Surface Treatment
[0050] After the high temperature/high pressure reaction, the product is filtered and washed to remove the solvent, re-dispersed in water, followed by surface treatment and drying the product.
[0051] The surface treatment is a process to inhibit deterioration of Mg—Ti—Al composite metal hydroxide particles themselves by halogen, which occurs during processing when the Mg—Ti—Al composite metal particles are used in a polymer, and to improve dispersibility of the particles, and the surface treatment is executed at 60 to 130° C. for 1 to 4 hours.
[0052] With regard to the surface treatment and/or coating treatment of the present invention, a surface treatment agent may include, for example, fatty acid, fatty acid salts, metal alkoxide, a silane coupling agent or mixtures thereof. Herein, the fatty acid is an acid including a linear or branched hydrocarbon group having 10 to 30 carbon atoms and may include saturated or unsaturated fatty acid such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, eicosanoic acid, arachidonic acid, erucic acid, 7, 10, 13, 16, 19-docosapentaenoic acid, etc., and fatty acid metal salts such as zinc stearate, calcium stearate, sodium stearate, sodium oleate, zinc oleate, zinc palmitate, etc.
[0053] Meanwhile, metal alkoxide may include metal alkoxides such as tetramethoxy silane, tetraethoxy silane, tetrapropoxy silane, tetrabutoxy silane, titanium tetraethoxide, titanium tetrapropoxide, titanium tetrabutoxide, zirconium tetraethoxide, zirconium tetrapropoxide, zirconium tetrabutoxide, aluminum triethoxide, aluminum tripropoxide, aluminum tributoxide, or the like.
[0054] The silane coupling agent may be at least one selected from a group consisting of 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl triethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxy-ethoxy)-silane, 2-(acryloxyethoxy)trimethylsilane, N-(3-acryloxy-2-hydroxypropyl)-3-amionpropyl triethoxysilane, N-(3-acryloxypropyl)dimethylmethoxysilane, (3-acryloxypropyl)methyl bis-(trimethylsyloxy)silane, (3-acryloxypropyl)methyldimethoxysilane, 3-(N-arylamino)propyl trimethoxysilane, allyldimethoxysilane, allyltriethoxysilane, butenyltriethoxysilane, 2-(chloromethyl)allyltrimethoxysilane, [2-(3-cyclohexenyl)ethyl]trimethoxysilane, 5-(bicycloheptenyl)triethoxysilane, (3-cyclopentadienylpropyl)triethoxysilane, 1,1-diethoxy-1-siryl acrylopen-3-en, (furfuryloxymethyl)triethoxysilahe, O-(methacryloxyethyl)-N-(triethoxysilylpropyl)urethane, N-(3-methacryloyl-2-hydroxypropyl)-3-aminopropyl triethoxysilane, (methacryloxymethyl)bis(trimethylsyloxy)methylsilane, (methacryloxymethyl)dimethylethoxysilane, methacryloxymethyl triethoxysilane, methacryloxymethyl trimethoxysilane, 3-methacryloxypropyl bis(trimethylsyloxy)methylsilane, methacryloxypropyldimethylethoxysilane, methacryloxypropyl dimethylmethoxysilane, methacryloxypropylmethyl diethoxysilane, methacryloxypropylmethyl dimethoxysilane, (3-acryloxypropyl)trimethoxysilane, methacryloxypropyl tris(methoxyethoxy)silane, methacryloxypropyl tris(vinyldimethoxysiloxy)silane, 3-(N-styrylmethyl-2-aminoethylamino)-propyltrimethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, N-2-(aminoethyl)-3-aminopropyl methyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyl triethoxysilane, 3-triethoxysiryl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyl trimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyl trimethoxysilane hydrochloride, 3-ureidopropyl triethoxysilane, 3-chloropropyl trimethoxysilane, 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl triethoxysilane, 3-glycidoxypropylmethyl diethoxysilane, 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, 3-mercaptopropylmethyl dimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyl triethoxysilane, 3-isocyanatopropyl trimethoxysilane, dimethyl dimethoxysilane, dimethyl diethoxysilane, 3-aminopropylmethyl diethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The surface treatment agent may be used alone or in combination with two kinds or more thereof. An added amount of the surface treatment agent may range from 0.1 to 10 wt. %, preferably, 0.5 to 5 wt. %. If the amount is less than 0.1 wt. %, dispersibility is not favorable. When the amount exceeds 10 wt. %, side effects and economic disadvantages may be caused by unreacted surface treatment agent.
[0055] Hereinafter, the present invention will be described in detail by the following examples, however, these examples are given for illustration and the present invention is not particularly limited to the examples.
EXAMPLE
[0056] In order to synthesize Mg—Ti—Al composite metal hydroxide particles having a laminated structure according to the present invention, an ultrasonic (processing) apparatus having an ultrasonic generator equipped with a Ti horn, a reactor, a constant-temperature bath, and a heater was installed.
[0057] The ultrasonic apparatus used in the present invention was an apparatus manufactured by SONIC & MATERIAL Co. (model name: VCX 1500), and a reaction was proceeded with a set frequency of 20 kHz and a fixed output of 1000 W. Moreover, a constant-temperature bath was used to maintain a constant temperature.
Example 1
[0058] In order to mix raw materials, 1.5 kg of water was put into a reactor, 4 moles of magnesium chloride and 0.1 mole of titanium tetrachloride were added to the reactor, and the mixture was stirred for 20 minutes and subjected to ultrasonic processing at 40° C. for 1 hour, followed by natural cooling. Next, after adding 2 moles of aluminum hydroxide and 5.5 moles of sodium hydroxide to 1.0 kg of water, the mixture was heated and dissolved and mixed with 1.5 moles of sodium carbonate to prepare a solution mixture. A magnesium/titanium solution was added to the prepared solution mixture and this prepared product was subjected to a reaction at high temperature/high pressure for 4 hours while maintaining a temperature of 170° C. and a pressure of 6.5 kg·f/cm 2 . After completing the reaction, filtering and washing were repeated and a resultant slurry thereof was dispersed in 3.0 kg of water to form a material at 90° C. Then, after agitating the formed material with sodium silicate No. 3 (0.1 mole of SiO 2 ) placed around the material for 2 hours, filtering and washing were repeated, The resultant product was separated and re-dispersed in 3.0 kg of water, followed by surface treatment using sodium stearate at 95° C. After completing the surface treatment, the treated product was filtered and washed further one time with a small amount of water. After filtering the same again, the product was dried at a temperature of not more than 150° C., thereby providing synthesized Mg—Ti—Al composite metal hydroxide particles having a laminated structure.
[0059] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 2
[0060] The same procedures as described in Example 1 were repeated, except that 0.6 mole of titanium tetrachloride, 1.5 moles of aluminum hydroxide and 6.5 moles of sodium hydroxide were used instead of 0.1 mole of titanium tetrachloride, 2 moles of aluminum hydroxide and 5.5 moles of sodium hydroxide.
[0061] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 3.98 Ti 0.61 Al 1.48 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.19 .2.8H 2 O
Example 3
[0062] The same procedures as described in Example 1 were repeated, except that 1.1 moles of titanium tetrachloride, 1 mole of aluminum hydroxide and 7.5 moles of sodium hydroxide were used instead of 0.1 mole of titanium tetrachloride, 2 moles of aluminum hydroxide and 5.5 moles of sodium hydroxide.
[0063] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.03 Ti 0.93 Al 1.05 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.23 .2.7H 2 O
Example 4
[0064] The same procedures as described in Example 1 were repeated, except that potassium phosphate was used instead of sodium silicate No. 3, and 1.0 mole of sodium carbonate and 1.0 mole of sodium sulfate were used instead of 1.5 moles of sodium carbonate.
[0065] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (PO 4 ) 0.08 (CO 3 ) 1.08 .2.9H 2 O
Example 5
[0066] The same procedures as described in Example 1 were repeated, except that 1.0 mole of sodium sulfate was used instead of sodium silicate No. 3 (SiO 2 , 1 mole).
[0067] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 3.97 Ti 0.08 Al 1.98 (OH) 12 (SO 4 ) 0.82 (CO 3 ) 0.92 .2.7H 2 O
Example 6
[0068] The same procedures as described in Example 1 were repeated, except that 1.0 L of ethanol was fed to the reactor instead of 1.5 kg of water and then 4 moles of magnesium chloride and 0.1 mole of titanium tetrachloride were added to the reactor.
[0069] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 7
[0070] The same procedures as described in Example 1 were repeated, except that 0.5 kg of water and 0.7 L of ethanol was fed to the reactor instead of 1.5 kg of water and then 4 moles of magnesium chloride and 0.1 mole of titanium tetrachloride were added to the reactor.
[0071] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 8
[0072] The same procedures as described in Example 1 were repeated, except that 1.0 L of propanol was fed to the reactor instead of 1.5 kg of water and then 4 moles of magnesium chloride and 0.1 mole of titanium tetrachloride were added to the reactor.
[0073] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 9
[0074] The same procedures as described in Example 1 were repeated, except that magnesium chloride was altered into magnesium nitrate, and aluminum hydroxide was altered into aluminum nitrate.
[0075] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 10
[0076] The same procedures as described in Example 1 were repeated, except that titanium tetrachloride was altered into titanium sulfate.
[0077] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 11
[0078] The same procedures as described in Example 1 were repeated, except that sodium hydroxide was altered into ammonia water.
[0079] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Example 12
[0080] The same procedures as described in Example 1 were repeated, except that the temperature of 200° C. and the pressure of 12 kg·f/cm 2 were maintained instead of the temperature of 170° C. and the pressure of 6.5 kg·f/cm 2 , respectively.
[0081] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Comparative Example 1
[0082] The same procedures as described in Example 1 were repeated, except that the ultrasonic processing was omitted.
[0083] From analysis results of the hydroxides described above, an empirical formula was practically represented by:
[0000] Mg 4.01 Ti 0.09 Al 1.99 (OH) 12 (SiO 3 ) 0.03 (CO 3 ) 1.16 .2.8H 2 O
Comparative Example 2
[0084] The present example was performed by using MAGCELER, which is commercially available in the market (Kyowa Chemical Industry Co., Ltd., Mg 4 Al 2 (OH) 12 (CO 3 ).3H 2 O).
Comparative Example 3
[0085] The present example was performed by using NAOX-33, which is commercially available in the market (TODA KOGYO CORPORATION, Mg 4 Al 2 (OH) 12 (CO 3 ).3H 2 O).
EXPERIMENTAL EXAMPLE
Determination of Thermal Stability (Heat Resistance)
[0086] The present experimental example was executed to determine thermal stability effects on chlorine-containing resins (PVC resin) of Mg—Ti—Al composite metal hydroxide particles synthesized in Examples 1 to 12, as compared to those in Comparative Examples 1 to 3. For thermal stability of resins, mixing ratios of constitutional materials used in Examples 1, Comparative Examples 1 to 3, respectively are shown as follows. Ingredients of a composition are given by a unit of parts per hundred resin (PHR).
[0087] PVC resin (polyvinylchloride resin, Hanwha L & C Co., Ltd.) 100 PHR
[0088] DOP (di-octyl phthalate, LG Chem., Ltd.) 25 PHR
[0089] Zn-St (zinc-stearate, Sinwon Chem., Ltd.) 0.3 PHR
[0090] Ca-St (calcium-stearate, Faci Asia Pacific Pte., Ltd.) 0.2 PHR
[0091] DEM (di-benzoylmethane, Changzhou nano chem., Ltd.) 0.1 PHR
[0092] Sample 2.0 PHR
[0093] The composition including the constitutional materials in the mixing ratios described above was mixed in a roll mill (a mixing roller, Ocean Science Ltd.) at 170° C. and 90 rpm for 3 minutes, and prepared into a specimen having a thickness of 0.6 mm. After cutting the specimen into pieces having a constant size, each piece was placed in a Matis Oven (Ocean Science Ltd.) and tested and assessed under conditions of a temperature of 200° C. and 3 mm/min. Results of the assessment are illustrated in FIGS. 3 to 5 .
[0094] Press Characteristics (Transparency)
[0095] After cutting a specimen into pieces having a constant size, each cut specimen having a size of 3 mm (0.6 mm×5) was placed in a heating press (Ocean Science Ltd.) and, after 30 minutes, it was measured whether discoloration had occurred or not. Such a measurement was conducted using a spectrophotometer (CM-3600, Konica Minolta Holdings, Inc.) and the measured L×(D65), a×(D65), b×(D65), WI(CIE) and YI(D1925) are illustrated in FIGS. 6 to 9 .
[0096] As shown in FIGS. 3 to 9 , it can be seen that the layered composite metal hydroxide synthesized according to the examples of the present invention has improved initial coloring and a favorable carbonizing time point, in addition, excellent press characteristics such as transparency, compared to the comparative examples. It was found that Comparative Example 2 exhibited deteriorated performances in terms of initial coloring of PVC resin, a carbonizing time point and press characteristics such as transparency, compared to Example 1 of the present invention. Further, according to X-ray diffraction analysis graphs of the layered composite metal hydroxide in FIG. 2 , it was demonstrated that the Mg—Ti—Al composite metal hydroxide according to Example 1 of the present invention has superior crystallinity over those in the comparative examples described above.
[0097] Although preferred embodiments of the present invention have been described in the above detailed description, the present invention is not restricted thereto. Therefore, those skilled in the art will appreciated that various variations and modification are possible in conventional production/research applications without departing from the scope and spirit of the present invention disclosed in the description, and such variations and modifications are dully within the appended claims.
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The present invention relates to a novel Mg—Ti—Al composite metal hydroxide and to production method therefor. Mg—Ti—Al composite hydroxide particles can be obtained by subjecting a solution containing a magnesium salt and a titanium salt to ultrasound processing and carrying out a high-temperature and high-pressure reaction with a solution containing an aluminum salt in the proportions of the metal elements comprised in the Mg—Ti—Al composite metal hydroxide, thereby giving the advantageous effects that the halogen capturing ability is excellent and, when used in a polymer, degradation and earily-staining prevention properties and transparency are outstanding.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part of U.S. patent application Ser. No. 09/165,658 filed Oct. 3, 1998.
FIELD OF THE INVENTION
[0002] The invention relates to notebook computers and wrist supports.
BACKGROUND OF THE INVENTION
[0003] Frequent use of computer keyboards can lead to hand strain and repetitive motion injuries such as Carpal Tunnel Syndrome. To prevent these injuries, cushioned pads have been developed that elevate and support a computer operator's wrists while the operator is using a computer keyboard.
[0004] A conventional wrist support pad is typically composed of a moldable, gel-like or sponge-like substance that is encased in a non-porous sheath and supported on its bottom by a rigid or semi-rigid base. It is rectangular in shape with a length generally greater than 18 inches and a width usually between about 3 and 5 inches. The length of the pad is fashioned so that it overlaps or approximates the width of a standard keyboard. The width of the pad is designed to accommodate an average person's wrist. Because conventional wrist support pads are generally not affixed to a keyboard or a computer, they may be placed in any one of a multitude of positions to suit a particular computer operator and/or a particular keyboard.
[0005] Although wrist support pads come in a variety of shapes and sizes, most are designed for use with the standard full-size keyboards that are commonly used with desktop computers, and not for the type of keyboards that are integrated within the body of portable notebook computers. Thus, existing wrist support pads are often awkward to use with notebook computers. For example, notebook computers often have keyboards that are placed several inches away from the front edge of the computer body. Positioning a wrist support pad immediately in front of the front edge of the computer body leaves the space between the pad and the keyboard too large for comfortable use by a person with average size hands. Moreover, positioning conventional wrist support pads on top of a notebook computer body immediately in front of the keyboard usually interferes with the use of other functional components of the computer, such as its pointing device (e.g., touchpad or trackball), microphone, or speakers.
SUMMARY OF THE INVENTION
[0006] The invention relates to notebook computers having built-in wrist support devices. The invention also relates to wrist support devices that are compatible with conventional notebook computers.
[0007] In one aspect, the invention features a notebook computer having a computer body, a keyboard, and a wrist support that is integrated within the computer body. In one variation of this notebook computer, the wrist support is integrated within the top panel of the computer body. In another variation, the wrist support is integrated within the front panel of the computer body.
[0008] In preferred embodiments, the notebook computers of the invention feature a wrist support that is reversibly inflatable. Some of these notebook computers further feature an inflation controller that includes a fluid pump and/or a bleed valve. In some variations, these notebook computers also feature an inflation control switch that regulates the inflation controller.
[0009] Also within the invention is a wrist support for use with a notebook computer keyboard. This wrist support includes a base having one or more flat surfaces, wherein the largest of these flat surfaces has a surface area of less than about 60 cm 2 . Some embodiments of this wrist support include a fastener for attaching the wrist support to a notebook computer. In the preferred embodiment, this wrist support features a reversibly inflatable bladder.
[0010] The invention also features a wrist support kit that includes the aforementioned wrist support with fastener, and an acceptor that can be affixed to a notebook computer in order to supply a connection site for the fastener.
[0011] Another feature of the invention is a notebook computer kit that includes a wrist support, a fastener, an acceptor, and a notebook computer. Some embodiments of this notebook computer kit also contain instructions for using (i.e., attaching the wrist support to the notebook computer) the notebook computer kit.
[0012] Also within the invention is a notebook computer including: a computer body having a front panel and a top panel, a keyboard, and a wrist support, the wrist support being compressible and integrated within the computer body. In various versions of this notebook computer the wrist support can be integrated within the top panel or the front panel of the computer body. In the latter, the front panel of the computer body can include a panel door behind which the wrist support can be stowed, and the panel door can be reversibly configurable between an open position and a closed position.
[0013] In notebook computers within the invention, the wrist support can be reversibly inflatable. For example, the notebook computer can further include an inflation controller fluidly connected to the wrist support. This inflation controller can include a fluid pump mounted on the notebook computer. In some variations, the inflation controller can include a bleed valve such as one that automatically opens when it is subjected to a predetermined threshold level. In other variations, the notebook computer can further include an inflation control switch operatively connected to the inflation controller, e.g., an inflation control switch that is switchable between an inflate position, a stop position, and a deflate position, whereby placement of the inflation control switch in the inflate position activates the inflation controller to inflate the wrist support, placement of the inflation control switch in the deflate position activates the inflation controller to deflate the wrist support, and placement of the inflation control switch in the stop position inactivates the inflation controller such that it neither inflates or deflates the wrist support. The inflation control switch can be a push-button type switch.
[0014] The notebook computers of the invention can also feature a wrist support that includes an elastic bladder, the bladder being fillable with a compressible substance such as a synthetic sponge (e.g., latex or synthetic rubber) and/or a fluid such as air.
[0015] The notebook computers of the invention, in some varaitations, also feature a wrist support that is reversibly detachable from the computer body. The wrist support can, for example, be attached to the computer body by a hook and loop type connector, a magnetic connector, or a mechanical connector.
[0016] Notebook computers within the invention can include a computer body having a front panel and a top panel, a keyboard, and a wrist support, the wrist support being filled with a gel and integrated within the computer body (e.g., into the front panel or top panel of the computer body). In versions where the wrist support is integrated within the top panel of the computer body, the computer body can further include at least one depression in the front panel of the computer body, the at least one depression being adapted to engage the wrist support.
[0017] Other notebook computers within the invention include a computer body having a front panel and a top panel, a keyboard, and at least a first and a second depression in the front panel of the computer body, the first depression being adapted to engage a first wrist support, and the second depression being adapted to engage a second wrist support. These notebook computers can further include a first gel-filled wrist support and a second gel-filled wrist support, the first gel-filled wrist support being mounted in the first depression, and the second gel-filled wrist support being mounted in the second depression. In addition these notebook computers can further include a pointing device, the pointing device being mounted on the computer body between the first depression and the second depression.
[0018] As used herein, the word “keyboard” is used in a generic sense to refer to any device that is used in a repetitive manner to input data into a computer, calculator or like device.
[0019] When one object is “integrated” within a second object, it is physically and functionally affixed to and designed to operate in accord with the second object. Thus, when a wrist support is “integrated” within a computer body, it is attached to the computer body in such a manner that both wrist support and computer body operate as one unit.
[0020] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In the case of conflict, the present specification, including definitions will control. In addition, the particular embodiments discussed below are illustrative only and not intended to be limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The invention is pointed out with particularity in the appended claims. The above and further advantages of this invention may be better understood by referring to the following description taken in conjunction with the accompanying drawings, in which:
[0022] [0022]FIG. 1 is a perspective view of one embodiment of the invention;
[0023] [0023]FIG. 2A is a right side view of the embodiment shown in FIG. 1, shown with the wrist support deflated and the video display support in the closed position;
[0024] [0024]FIG. 2B is a right side view of the embodiment shown in FIG. 1, shown with the wrist support deflated and the video display support in the open position;
[0025] [0025]FIG. 2C is a right side view of the embodiment shown in FIG. 1, shown with the wrist support inflated and the video display support in the open position;
[0026] [0026]FIG. 2D is a side view of the wrist support, inflation controller, and inflation control switch of the embodiment shown in FIG. 1, shown with the wrist support fluidly connected to the inflation controller, and the inflation control switch operatively connected to the inflation controller.
[0027] [0027]FIG. 3A is a perspective view of another embodiment of the invention, shown with the wrist support panel door in the closed position;
[0028] [0028]FIG. 3B is a perspective view of the embodiment shown in FIG. 3A, shown with the wrist support panel door in the open position and the wrist support deflated;
[0029] [0029]FIG. 3C is a perspective view of the embodiment shown in FIG. 3A, shown with the wrist support panel door in the open position and the wrist support inflated;
[0030] [0030]FIG. 4A is a side view of a detachable wrist support shown in an uninflated position;
[0031] [0031]FIG. 4B is a side view of the detachable wrist support featured in FIG. 4A shown in an inflated position;
[0032] [0032]FIG. 4C is a side view of a notebook computer and a detachable wrist support, shown with the wrist support detached from the notebook computer;
[0033] [0033]FIG. 4D is a side view of a notebook computer and a detachable wrist support, shown with the wrist support attached to the notebook computer and in an uninflated position;
[0034] [0034]FIG. 4E is a side view of a notebook computer and a detachable wrist support, shown with the wrist support attached to the notebook computer and in an inflated position; and
[0035] [0035]FIG. 5 is a perspective view of a notebook computer and a detachable wrist support, shown with the wrist support attached to the notebook computer.
[0036] [0036]FIG. 6 is a cross-sectional view taken through the body of a notebook computer having a gel-filled wrist support integrated in the computer body.
DETAILED DESCRIPTION
[0037] The invention encompasses notebook computers having an integrated wrist support as well as standard notebook computer components such as a keyboard, pointing device and computer body. As can be seen by comparing different models of currently available notebook computers (e.g., IBM Thinkpad 770™ and Compaq Presario® computers), these standard components may be arranged in myriad different orientations. This notwithstanding, two types of conventional layouts predominate in the marketplace. The first of these has a keyboard oriented on top of the computer body near the video display (see, e.g., FIG. 1). This layout features a relatively large unoccupied space on top of the computer body in the area between the keyboard and the front edge of the computer body. A pointing device such as a touchpad is usually located within this space. In the second type of conventional layout, the keyboard is placed on top of and near the front edge the computer body (see, e.g., FIG. 3A). This layout has only a very small unoccupied space on top of the computer body in the area between the keyboard and the front edge of the computer body.
[0038] The below described preferred embodiments illustrate adaptations of wrist supports for use with notebook computers having their components arranged in each of these two conventional layouts. Nonetheless, from the description of these embodiments, other notebook computers of the invention can be readily fashioned by repositioning and/or making slight modifications to the components discussed below.
[0039] In brief overview, referring to FIGS. 1, 2A, 2 B, 2 C, and 2 D, an embodiment of notebook computer 5 includes a computer body 10 having a front panel 11 , side panels 12 (right side panel is shown; left side panel is not shown), a top panel 13 a , a bottom panel 13 b and a back panel 14 ; a video display support 15 containing a video display 16 ; wrist supports 17 a (left) and 17 b (right); a pointing device 18 ; a keyboard 19 ; an inflation controller 20 ; an inflation control switch 21 ; a fluid connector 28 ; and a switch connector 29 .
[0040] The notebook computer 5 shown in FIGS. 1, 2A, 2 B, and 2 C shares many of the same components featured in conventional notebook computers. For example, the bulk of the physical structure of notebook computer 5 consists of computer body 10 and video display support 15 . Each of these serve as a supportive and protective housing for other components of the computer. Both computer body 10 and video display support 15 are typically composed of a hard durable material such as a plastic (e.g., polyvinyl chloride) or a metal alloy (e.g., a magnesium alloy). Computer body 10 has a rectangular polyhedron shape formed by front panel 11 , side panels 12 , top panel 13 a , bottom panel 13 b and back panel 14 . It is movably attached to video display support 15 by a hinge such that video display support 15 can be reversibly positioned immediately on top of and roughly parallel to top panel 13 a (i.e., in the closed position; see FIG. 2 A for example) or at various angles away from top panel 13 a (i.e., in an open position; see FIGS. 2B and 2C for example). The interior of computer body 10 houses various functional parts of the computer such as a central processing unit (CPU), a hard drive, a floppy disk drive, a CD-ROM drive, a battery, etc. The exterior of computer body 10 features devices such as pointing device 18 , keyboard 19 , a power switch, a microphone, speakers, etc. Video display support 15 houses video display 16 (e.g., an LCD video monitor) which is operatively linked to other functional parts of the computer. The above features are functionally connected in a similar manner as in conventional notebook computers.
[0041] Also included within the notebook computer 5 shown in FIGS. 1, 2A, 2 B, and 2 C are wrist supports 17 a (left) and 17 b (right), inflation controller 20 , and inflation control switch 21 . In the embodiment shown, wrist supports 17 a (left) and 17 b (right) are integrated into computer body 10 at the portions of top panel 13 a on each side of pointing device 18 in a position immediately forward of keyboard 19 . This orientation is such that the user of notebook computer can comfortably rest his wrists or palms on wrist supports 17 a (left) and 17 b (right) while his fingers are located in a position convenient for typing on keyboard 19 . Wrist supports 17 a and 17 b are basically bladders composed of an elastic material (e.g., latex or synthetic rubber) that are fillable with a fluid such as a gas (e.g., air, carbon dioxide, or nitrogen) and fluidly connected to a fluid source (e.g., atmospheric air) via fluid connector 28 (see FIG. 2D), a device for transferring fluid from one source to another (e.g., non-porous tubing or the like). They may optionally be covered with fabric (e.g., nylon, polyester, etc.) to enhance their comfort and durability. Each wrist support 17 is reversibly expandible in size by adding or decreasing the amount of fluid contained therein. Wrist supports 17 a and 17 b may be fluidly connected to each other to form one structure (i.e., wrist support 17 ). Alternatively, wrist supports 17 a and 17 b can lack a fluid connection to each other. The latter configuration is preferred where it is desirable to have left and right wrist supports that are independently adjustable.
[0042] Inflation controller 20 is a device that regulates the amount of fluid in wrist support 17 . In a preferred embodiment, inflation controller 20 comprises a two-way fluid pump that is mounted at a predetermined location on notebook computer 5 (e.g., on computer body 10 at side panel 12 as shown in FIG. 1). In another preferred embodiment, inflation controller 20 comprises a fluid pump and a bleed valve. In either case, as shown in FIG. 2D, the fluid pump (and the bleed valve in the latter configuration) of inflation controller 20 is connected to wrist support 17 and a fluid source (e.g., the air in the atmosphere surrounding notebook computer 5 ) by fluid connector 28 such that the fluid may reversibly flow from the fluid source through inflation controller 20 into wrist support 17 . Where wrist supports 17 a and 17 b are not fluidly connected to each other, inflation controller 20 is separately connected to wrist support 17 a and wrist support 17 b such that it independently controls inflation of each wrist support (e.g., there is a separate fluid pump for each wrist support).
[0043] Activation of inflation controller 20 causes fluid to flow through fluid connector 28 between the fluid source (e.g., atmospheric air) and wrist support 17 . Activation of the fluid pump portion of inflation controller 20 in a forward direction causes fluid to move from the fluid source through inflation controller 20 into wrist support 17 , thus inflating wrist support 17 . Activation of the fluid pump of inflation controller 20 in a reverse direction causes fluid to move from wrist pad 17 through inflation controller 20 out to the fluid source (e.g., the atmosphere), thus deflating wrist support 17 . In the configuration of inflation controller 20 that includes a bleed valve, opening the bleed valve causes fluid to flow out of wrist support 17 fluid connector 28 through fluid connector 28 into the atmosphere via inflation controller 20 , thus deflating wrist support 17 . In some configurations, the bleed valve portion of inflation controller 20 can be set to automatically open when a threshold fluid pressure is reached. Thus, when wrist support 17 reaches a certain predetermined size or pressure, the bleed valve opens and thereby releases fluid from wrist support 17 . In this manner, the maximum size to which wrist support 17 can be expanded can be automatically controlled.
[0044] Inflation control switch 21 is a switch device that regulates the operation of inflation controller 20 . It is mounted on a predetermined site on notebook computer 5 that is accessible to a user. For example, in the embodiment shown in FIG. 1, inflation control switch 21 is affixed to computer body 10 on top panel 13 a near video display support 15 . As shown in FIG. 2D, inflation control switch 21 is operatively linked (e.g., mechanically, hydraulically, or electrically) to inflation controller 20 via switch connector 29 , a device that operatively links inflation control switch 21 to inflation controller 20 (e.g., an electrical wire, a mechanical cable, or hydraulic hosing). It has an inflate position, a stop position, and a deflate position. When placed in the inflate position, inflation control switch 21 signals inflation controller 20 to activate its fluid pump to send fluid into and thereby inflate wrist support 17 . When placed in the deflate position, inflation control switch 21 signals inflation controller 20 to reverse its fluid pump and/or open its bleed valve to thereby deflate wrist support 17 . When placed in the stop position, inflation control switch 21 signals inflation controller 20 to either stop inflating or stop deflating wrist support 17 .
[0045] An overview of the operation of the foregoing preferred embodiment is shown in FIGS. 2A, 2B, and 2 C. In FIG. 2A, notebook computer 5 is shown in the closed position with wrist support 17 deflated. Deflation of wrist support 17 permits video display support 15 to be placed immediately on top of and roughly parallel to top panel 13 a so that notebook computer 5 is in a compact configuration (i.e., with video display support 15 in the closed position) that enhances the portability of notebook computer 5 . To operate notebook computer 5 , a user moves video display support 15 to an open position such that the user can view video display 16 (see, e.g., FIG. 2B) and then boots up the computer. To utilize wrist support 17 , the user then places inflation control switch 21 in the inflate position, thus activating the fluid pump of inflation controller 20 to send fluid into wrist support 17 via fluid connector 28 . When wrist support 17 is inflated to the desired size (one example is depicted in FIG. 2C), the user then places inflation controller switch 21 in the stop position to halt fluid flow into wrist support 17 . Thus, in this configuration, the user can operate notebook computer 5 much like a conventional notebook computer except that his wrists or palms are comfortably propped on inflated wrist support 17 . Because wrist support 17 can be inflated to an infinite number of positions up to a maximum inflation position, each different user can adjust the size of wrist support 17 to his liking.
[0046] When the user has completed operating notebook computer 5 , he can restore it to the compact and portable configuration shown in FIG. 2A by placing inflation control switch 21 in the deflate position. In this position, inflation control switch 21 causes deflation of wrist support 17 by activating the fluid pump of inflation controller 20 to remove the fluid from wrist support 17 and/or opening the bleed valve portion of inflation controller 20 to thereby release the fluid from wrist support 17 . In some variations of this embodiment, the user can apply pressure to wrist support 17 (e.g., by manually squeezing wrist support 17 ) to hasten the release of fluid from (and thus deflation of) wrist support 17 . When a sufficient amount of fluid is removed from wrist support 17 , inflation control switch 21 is placed in the stop position. The user can then place video display support 15 immediately on top of and roughly parallel to top panel 13 a (FIG. 2A).
[0047] In another variation of this preferred embodiment, operation of inflation control switch 21 is automatic or semiautomatic. For example, as shown in FIGS. 1, 2A, 2 B, and 2 C, inflation control switch 21 is positioned on top panel 13 a adjacent to video display support 15 . In this variation, inflation control switch 21 is designed as a pushbutton-type device (e.g., a spring-loaded piston movably mounted within an open-ended cylinder) that has a depressed position where the top of the pushbutton is approximately flush with the surface of top panel 13 a , and non-depressed positions where the pushbutton extends perpendicularly away from top panel 13 a for various short distances (such as 0.5, 1, or 2 cm) up to a maximum non-depressed position in which the pushbutton is fully extended. The pushbutton-type device is biased so that it is in the maximum non-depressed position in the absence of extraneous forces.
[0048] When the video display support of notebook computer 5 is in the closed position (such as shown in FIG. 2A), the pushbutton of inflation control switch 21 is held in the depressed position by contact from a portion of video display support 15 . This position corresponds to the stop position discussed above (i.e., inflation controller 20 is inactivated). When video display support 15 is placed in an open position, the pushbutton of inflation control switch 21 rises to a non-depressed position as a result of its bias. This movement from a depressed position to a non-depressed position places inflation control switch 21 in the inflate position and thereby signals inflation controller 20 to send fluid into wrist support 17 . After wrist support 17 reaches a preset inflation level, inflation controller 20 automatically returns to an inactivated state (e.g., inflation controller 20 has a pressure sensor that turns off the fluid pump of inflation controller 20 when a threshold pressure is detected). Because the pushbutton of inflation control switch 21 abuts against a portion of video display support 15 , lowering video display support 15 to return it to the closed position gradually pushes inflation control switch 21 downward toward the depressed position. This downward push places inflation control switch 21 in the deflate position and thereby signals inflation controller 20 to remove fluid from wrist support 17 . With wrist support 17 deflated, video display support 15 can be returned to the closed position in which inflation control switch 21 is in the depressed or stop position.
[0049] Another preferred embodiment of the invention is shown in FIGS. 3A, 3B, and 3 C. Similarly to the notebook computer discussed above and shown in FIGS. 1, 2A, 2 B, 2 C and 2 D, this embodiment is a notebook computer that includes a computer body 10 having a front panel 11 , side panels 12 (right side panel is shown; left side panel is not shown), a top panel 13 a , a bottom panel 13 b (not shown) and a back panel 14 (not shown); a video display support 15 containing a video display 16 ; a wrist support 17 ; a keyboard 19 ; an inflation controller 20 ; an inflation control switch 21 ; a fluid connector 28 (not shown); and a switch connector 29 (not shown). To illustrate how the above components of the notebook computers of the invention can be arranged in different orientations, notebook computer 5 in FIG. 1 can be compared to notebook computer 5 in FIG. 3A. For example, in the embodiment shown in FIG. 3A, keyboard 19 is oriented closer to front panel 11 than in the embodiment shown in FIG. 1. Likewise, inflation control switch 21 is mounted on top panel 13 a near front panel 11 in the embodiment shown in FIG. 3A, whereas it is mounted near video display support 15 in the embodiment shown in FIG. 1.
[0050] In the embodiment shown in FIGS. 3A, 3B, and 3 C, wrist support 17 of notebook computer 5 is contained within computer body 10 immediately behind front panel 11 . This embodiment is preferred for notebook computers having a keyboard placed on top panel 13 a at a location near front panel 11 (e.g., IBM Thinkpad 770™) as the lack of available space on the portion of top panel 13 a in front of keyboard 19 does not limit placement of wrist support 17 . This embodiment optionally features a wrist support panel door 22 that is composed of a material similar to that composing computer body 10 (such as plastic or metal). Wrist support panel door 22 is typically rectangular in shape, and attached to and integrated within front panel 11 . As an example, FIGS. 3A and 3B show wrist support panel door 22 hingedly attached to the bottom of front panel 11 . Wrist support panel door 22 has a closed position and open positions. In the closed position, wrist support panel door 22 is reversibly locked into computer body 10 by wrist support panel door clasp 22 a (any number of such clasps can be used; FIG. 3A shows two such clasps). One open position of wrist support panel door 22 is shown in FIG. 3B. Although wrist support panel door 22 is not required for the function of this embodiment, it is generally a preferred component as it protects wrist support 17 from damage and provides a convenient mechanism for storing wrist support 17 while it is not being used. One exemplary alternative configuration of this embodiment (not shown) has wrist support 17 integrated into computer body 10 at front panel 11 with front panel 11 having a cut-out portion through which wrist support 17 can expand. This configuration resembles notebook computer 5 shown in FIG. 3B except that wrist support panel door 22 is omitted.
[0051] In the preferred embodiment, wrist support 17 is a single unit (albeit, multiple wrist supports could also be used) that is essentially a bladder composed of an elastic material (e.g., latex or synthetic rubber). This bladder is fillable with a fluid such as a gas (e.g., air, carbon dioxide, or nitrogen) and fluidly connected to a fluid source (e.g., atmospheric air) via fluid connector 28 (not shown, but see FIG. 2D for a similar example), so that wrist support 17 can be reversibly expanded by adding or decreasing the amount of fluid contained therein. Wrist support 17 is shaped (e.g., the elastic material is pre-molded) so that when expanded it develops a shape conducive for comfortable typing by an operator of the notebook computer. It may optionally be covered with fabric (e.g., nylon or the like) to enhance its feel (i.e., comfort for a user) and/or durability.
[0052] The components of this embodiment function quite similarly to the components of the embodiment shown in FIGS. 1, 2A, 2 B, and 2 C. For example, in this embodiment, inflation controller 20 also comprises a two-way fluid pump (or a fluid pump and a bleed valve) that is mounted at a predetermined location on notebook computer 5 . It is also connected to wrist support 17 and a fluid source (e.g., the air in the atmosphere surrounding notebook computer 5 ) via fluid connector 28 (not shown) such that the fluid can reversibly flow from the fluid source through inflation controller 20 into wrist support 17 . Activation of the fluid pump portion of inflation controller 20 in a forward direction causes fluid to flow into (and thereby inflate) wrist support 17 . Reversing the direction of the fluid pump removes fluid from (and thereby deflates) wrist pad 17 . Where a bleed valve is included as part of inflation controller 20 , opening the bleed valve causes fluid to flow out of (and thereby deflate) wrist support 17 .
[0053] This embodiment also features an inflation control switch 21 for regulating the operation of inflation controller 20 . It is placed at a predetermined site on notebook computer 5 (in FIGS. 3A, 3B, and 3 C it is shown on top panel 13 a near front panel 11 and right side panel 12 ), and is operatively linked to inflation controller 20 via switch connector 29 (not shown; but see FIG. 2D for a similar example). It has an inflate position, a stop position, and a deflate position. When placed in the inflate position, inflation control switch 21 signals inflation controller 20 to activate its fluid pump to send fluid into and thereby inflate wrist support 17 . When placed in the deflate position, inflation control switch 21 signals inflation controller 20 to reverse it fluid pump and/or open its bleed valve to thereby deflate wrist support 17 . When placed in the stop position, inflation control switch 21 signals inflation controller 20 to either stop inflating or stop deflating wrist support 17 .
[0054] The operation of this preferred embodiment is very similar to the operation of the embodiment shown in FIGS. 2A, 2B, 2 C, and 2 D. In FIG. 3A, notebook computer 5 is shown with wrist support 17 deflated and wrist support panel door 22 in the closed position. To inflate wrist support 17 , the user first opens wrist support panel door 22 and then places inflation control switch 21 in the inflate position, thus activating the fluid pump of inflation controller 20 to send fluid into wrist support 17 . In one variation of this embodiment, wrist support panel door clasp 22 a can be designed so that wrist support panel door 22 automatically opens while wrist support 17 is being inflated. For example, wrist support panel door clasp 22 a can be a hook and loop-type connector (e.g., Velcro®) that comes apart when subjected to a predetermined force such as the pressure caused by the inflation of wrist support 17 . When wrist support 17 is inflated to a desired size (e.g., as depicted in FIG. 3C), the user then places inflation controller switch 21 in the stop position to cut off fluid flow into wrist support 17 . To restore the compact and portable configuration of notebook computer 5 (as shown in FIG. 3A), inflation control switch 21 is placed in the deflate position. This causes inflation controller 20 to remove the fluid from wrist support 17 as described supra. In some cases, the user can apply pressure to wrist support 17 to hasten deflation of wrist support 17 . When a sufficient amount of fluid is removed from wrist support 17 , inflation control switch 21 can be placed in the stop position. The deflated wrist support 17 can be stowed in computer body 10 and secured by closing wrist support panel door 22 .
[0055] As shown in FIGS. 4A, 4B, 4 C, 4 D, 4 E, and 5 , another preferred embodiment of the invention is a wrist support that is detachably affixable to the body of a notebook computer. In this embodiment, wrist pad 17 includes an inflation controller 20 , a base 23 , a bladder 24 , bladder cover 25 , and a fastener 26 . To facilitate compatibility with notebook computers, the total area of the largest flat surface of wrist pad 17 is less than about 60 cm 2 (e.g., 25, 30, 45, 50, or 55 cm 2 ). The specific dimensions and shape of wrist pad 17 can be chosen to match the particular layout of a given notebook computer.
[0056] Although, in some embodiments, base 23 can be used alone as a wrist support (especially if base 23 is composed of a soft, compressible material such as synthetic sponge such as latex or synthetic rubber), in the particular embodiment shown in FIGS. 4A, 4B, 4 C, 4 D, 4 E, and 5 , base 23 is a structure that forms and maintains the shape of the bottom portion of wrist pad 17 . It is roughly rectangular in shape and composed of a rigid or semi-rigid material such as plastic or reinforced rubber. Base 23 also serves as a structure on which to mount other components of wrist pad 17 such as bladder 24 , bladder cover 25 , and/or fastener 26 .
[0057] Bladder 24 is fixedly attached to base 23 . It is essentially an elastic balloon (e.g., a latex or synthetic rubber balloon) that is fillable with a compressible substance such as a gas (e.g., air, carbon dioxide, or nitrogen) or a sponge-like material (e.g., latex or synthetic rubber). By adding or decreasing the amount of compressible substance contained within bladder 24 (e.g., via a connection to a source of said substance), wrist support 17 can be reversibly expanded.
[0058] In a preferred configuration of this embodiment, the compressible substance is atmospheric air. In this configuration, bladder 24 is biased so as to be in an expanded configuration when not subjected to an extraneous force (much like the inflation bulb in a standard manual sphygmomanometer). Bladder 24 communicates with the atmosphere via inflation controller 20 , which in this embodiment is a valve directly attached to bladder 24 that has an open and a closed position. When inflation controller 20 is in the open position, air from the atmosphere can flow in and out of bladder 24 . When inflation controller 20 is in the closed position, air from the atmosphere cannot flow in or out of bladder 24 . Because of bladder 24 's bias, when inflation controller 20 is in the open position bladder 24 is in an inflated state (see FIG. 4B). When the inflation controller 20 is then placed in the closed position, air cannot escape bladder 24 , and thus wrist support 17 is stabilized in the inflated state. When inflation controller 20 is left in the open position, a user can compress (e.g., by manually squeezing) bladder 24 to a desired inflation state and then close inflation controller 20 so that the chosen inflation state is stabilized (see FIG. 4A).
[0059] Similarly, a user can partially or completely deflate wrist support 17 by partially or fully compressing bladder 24 . This deflated state can be stabilized by either continuing the compressing force, or by placing inflation controller 20 in the closed position. In this manner the size of wrist support 17 can be minimized to facilitate its portability and/or storage. In some variations, wrist support 17 can be deflated while attached to a notebook computer so that the video display support of the notebook computer can be placed in the closed position without wrist support 17 being detached.
[0060] Other components of the wrist support device shown in FIGS. 4A, 4B, 4 C, 4 D, 4 E, and 5 include bladder cover 25 , fastener 26 , and acceptor 27 . Bladder cover 25 is a piece of fabric (e.g., nylon or the like) that is placed over bladder 24 (as shown in FIGS. 4A and 4B) in order to reinforce and protect bladder 24 , and/or to enhance the esthetics or feel (for user comfort) of wrist pad 17 . Fastener 26 and acceptor 27 are devices used for attaching wrist support 17 to notebook computer 5 .
[0061] Fastener 26 is attached to the bottom portion of wrist support 17 . It can be any type of device that can mediate the attachment of wrist support 17 to the surface of computer body 10 (e.g., an adhesive tape, a magnet, or a mechanical lock). In the preferred embodiment shown in FIGS. 4A, 4B, 4 C, 4 D, and 4 E, fastener 26 is a one component of a hook and loop-type connector such as Velcro® (i.e., fastener 26 is the hook or the loop component of the connector). In this configuration, to affix wrist support 17 to notebook computer 5 , acceptor 27 is first mounted (e.g., using an adhesive) to an unoccupied area on the surface of computer body 10 (see FIG. 4C). Acceptor 27 is one component of a two component connector (e.g., a hook and loop-type connector) that is attachable to fastener 26 . For example, in the preferred embodiment, where fastener 26 is the hook component of a hook and loop-type connector, acceptor 27 will be the loop component of the connector, and vice versa. As shown in FIG. 4D, wrist support 17 is then placed onto notebook computer 5 so that fastener 26 engages acceptor 27 . Wrist support 17 is thus affixed to the notebook computer (see FIG. 4D for a side view and FIG. 5 for a perspective view). While in this position wrist support 17 can be in a deflated position (FIG. 4D) or an inflated position (FIG. 4E). Wrist pad 17 can be removed from notebook computer 5 by simply prying it from the surface of computer body 10 with sufficient force to disengage fastener 26 from acceptor 27 . Wrist pad 17 can also be connected to computer body 10 by means of a magnetic connector, a mechanical connector, or any other suitable fastening device.
[0062] Also within the invention are gel-filled wrist supports for use with a notebook computer and notebook computers having a gel-filled wrist support integrated with the body of the notebook computer (e.g., in the top panel or in the front panel). These embodiments are similar to the fluid-fillable wrist support shown in the figures and described above except that the fluid is a gel such as a water-based gel, a stable elastomeric block polymer gel, urethane, and any other suitable gel. Examples of suitable elastomeric block polymer gels can be found in U.S. Pat. Nos. 3,676,388, 4,369,284, 5,633,286 and 5,713,544. Examples of polyurethane gels include those in U.S. Pat. Nos. 4,346,205; 4,476,258; 4,722,946; and 4,980,386.
[0063] The overall dimensions of the gel-filled wrist pad can be any suitable for use with a notebook computer, e.g., sized to fit on the top panel of a notebook computer without interfering with the operation of the notebook computer's other components (e.g., pointing device or keyboard). The thickness (i.e., from the bottom surface to the top surface of the wrist pad) of the wrist pad can be any suitable for comfortable use with a notebook computer, for example, between about 3 and 30 mm (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 mm). For use with conventional notebook computers, the thickness of the wrist pad, especially in those versions in which the gel is sealed within the wrist pad, is preferably small enough (e.g., between about 0.5 and 10 mm or between 1 and 5 mm) so that once the wrist support(s) is mounted on the top panel of the notebook computer, the computer can be placed in the open and closed configurations without having to remove the wrist support(s).
[0064] For the notebook computers having a wrist support integrated in the top panel of the computer body, referring now to FIG. 6, the top panel can have one or more recessed depressions 42 (e.g., one or two receded portions of computer body 10 that can be circumscribed by a rigid material such as plastic) into which wrist support 17 (e.g., one that takes the form of a bladder 24 filled with gel 40 as shown in FIG. 6 or another wrist support described herein) can be inserted such that the thickness of the wrist support that projects above the top panel is reduced or eliminated. Depressions 42 can be of any size or shape suitable for accepting a wrist support. For example, they can have a depth (the distance from the plane of the top panel to the bottom of the depression) of between about 3 and 30 mm (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 mm). The other dimensions of the wrist pad should be suitable for being used in a notebook computer without interfering with the operation of other notebook computer components such as the pointing device and the key board. For example, the surface area of the bottom portion of the wrist pad 17 (i.e., the portion of wrist pad 17 in contact with the bottom of the depression 42 as shown in FIG. 6) can be less that about 100 cm 2 (e.g., 30, 40 , 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 cm 2 ), although it can be larger in some configurations. The surface area of the top portion of wrist pad 17 (that is the portion of wrist pad 17 that would contact the notebook computer user's wrist or palm) should be large enough to support an average size wrist, e.g., between about 30 and 100 cm 2 (e.g., 40-90 cm 2 , 50-80 cm 2 or 60-70 cm 2 ). The gel-filled wrist support of the invention can additionally feature a cover made of a durable material and/or a means for attaching the wrist pad to the depression (e.g., for versions of the wrist pads that are reversibly detachable from the computer body). Suitable materials for the cover and means for attaching the wrist pad to the depression are described above for other embodiments of the invention.
[0065] From the foregoing, it can be appreciated that the notebook computers and wrist supports of the invention permit the use of a keyboard in a comfortable and ergonomic manner.
[0066] While the above specification contains many specifics, these should not be construed as limitations on the scope of the invention, but rather as examples of preferred embodiments thereof. Many other variations are possible. For example, a notebook computer having an inflatable wrist support integrated into the top panel of the computer body wherein inflation of the wrist support causes it to expand in such a manner as to overlap the front panel of the computer body, is included within the invention. As another example, a notebook computer having a wrist support in communication with a self-contained, pressurized fluid reservoir (e.g., a tank containing pressurized nitrogen gas) such that the fluid reservoir can provide fluid to inflate the wrist support is within the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.
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Notebook computers having an integrated wrist support device are disclosed. Also disclosed are wrist supports for use with notebook computer keyboards, a wrist support kit, and notebook computer kits.
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