description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
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The invention relates generally to clutch mechanisms and, more particularly, to a safety clutch for protecting machine drive lines especially useful in connecting the drive shafts of agricultural implements such as tractors or the like.
A clutch mechanism of the type to which the present invention relates generally consists of a clutch hub and a clutch sleeve, with spring-loaded dog members guided in pockets of the clutch hub being operative to engage within recesses in the clutch sleeve to effect torque transmission between the hub and the sleeve. The dog members may be formed with wedged engagement heads and the clutch sleeve recesses taper radially outwardly for engagement with the wedged heads.
Safety clutches operating on the principle of a clutch ratchet are known in the art. However, disadvantages commonly found in such ratchet clutches involve high noise levels, overheating and high degrees of wear. It has been attempted to avoid such disadvantages by, means of a switching effect as indicated in the prior art in East German Pat. No. 8568. In the case of the safety clutch described therein, spring loaded dog elements which are designed as spherical balls are guided in one part of the clutch and engage into groove-type notches of the other part of the clutch. The notches guide prismatic filler pieces which, after the balls have moved out of the grooves of the other part of the clutch in the case of clutch overloading, are pushed radially outwardly by centrifugal force. Thus, the grooves are closed for the balls in the torque transmitting position. The safety clutch is thus switched into a free wheeling position and the balls move across the filler pieces without an unpleasant rattling effect commonly found in ratchet clutches of the prior art.
The outer ends of the grooves are provided with apertures whereby by means of engagement of a tool, the filler pieces may be moved back into the starting position. As a result, the safety clutch may be switched back into torque transmitting condition.
The disadvantage of a design of the type described is that for the purpose of re-engaging the safety clutch, driving operation must be terminated completely and a manual operation is necessary in order to re-establish the torque transmitting condition. Thus, when using such a clutch for safety purposes in a drive line between a tractor and an agricultural implement, the tractor operator must leave the tractor after each case of overloading in order to manually place the clutch into the working position. This places an unacceptable burden on the tractor operator, particularly when work is being performed in difficult areas such as stony fields.
Thus, it is the purpose of the present invention to provide a safety clutch which operates on the ratchet principle and which will automatically switch to a free wheeling position when a predetermined nominal torque is exceeded, with the clutch returning to the torque transmitting position without requiring any manual operation. For example, with the clutch of the present invention, return to the torque transmitting condition may occur simply by reducing the drive speed. The invention also provides a simple design which involves reasonable production costs.
SUMMARY OF THE INVENTION
Briefly, the present invention may be described as a clutch for a machine drive wherein the recesses in the clutch sleeve are formed with a dimension in the circumferential direction which is longer than the engaging wedged head parts of the dog members. The outside of the wedge-shaped head parts of the dog members are provided with flattened faces and in the torque transmitting position, the space remaining in the recesses is filled in each case by a movable control strip. If the dog members are not engaged in the recesses, the distance of movement of the control strips in the circumferential direction is equal to or smaller than the head width of the flattened face of the dog members.
Adjustment in the circumferential direction between the length of the recesses, the distance of movement of the control strips and the head width of the flattened areas of the dog members ensures that as a result of frictional forces between the control strips and the dog members, the control strips are moved along in the recesses in the direction of rotation after an overloading has occurred and they are made to stop thereby producing, on the side of the recesses away from the direction of rotation, a compensation space which is not however large enough for the head parts of the dogs to enter and engage. However, on the side of the recesses facing the direction of rotation, there remains a space which is geometrically sufficient for the head parts of the dog members to fall into to a certain radial degree but which on the other hand is not large enough for the head parts of the dog members to catch in the space when the safety clutch continues to run at nominal speed.
The effect of the foregoing is that after overloading the safety clutch continues to rotate at a greatly reduced torque. The invention thus avoids many of the disadvantages commonly found in ratchet clutches.
However, when speed is reduced, it becomes possible for the head parts of the dog members to engage in the spaces facing the direction of rotation and to push back the control strips in the recesses against the direction of rotation. This process is favored by the considerable rotational vibrations occurring when driving agricultural machinery as a result of which the safety clutch will automatically switch back into the torque transmitting position.
In a further feature of the invention, the space remaining in the recesses in the torque transmitting position is filled by two control strips which are arranged on each side of the head part of the dog member.
This design of the safety clutch has the advantage that it is suitable for use in drive mechanisms which operate in two directions of rotation.
In accordance with a further characteristic of the invention, the control strips project from the recesses toward the clutch hub on the side thereof away from the direction of rotation. An advantage of this design is that the control strips will be positively switched to the free wheeling position by the head parts of the dog members thereby avoiding any dependence upon any changes in frictional conditions within the safety clutch which might be the result of lubrication or similar effects.
In a further embodiment of the invention, the radial thickness of the control strips is increased in the direction of rotation allocated thereto.
Because of the wedge-shaped design of the control strips, they will receive a force component acting in the direction of rotation as a result of the spring force transferred thereto by the head parts of the dog members.
In accordance with a further advantageous characteristic of the invention, the control strips are formed to be thicker than the depth of the recesses taken in the radial direction and each control strip is provided with an extension pointing away from the center of the recess in the circumferential direction and covering at least partially the inner annular face of the clutch sleeve.
This embodiment of the invention provides the advantage that the head parts of the dog members when passing through the safety clutch do not slide along the inner wall of the clutch sleeve, but are supported by the inner face of the control strips or their extensions. This arrangement avoids any type of wear on the clutch sleeve so that partial hardening of the running face of the clutch sleeve may not be necessary.
In a further advantageous embodiment of the invention, some of the recesses are provided with movable control strips and others are provided with an opening corresponding to the shape of the head parts of the dog members.
Since some of the recesses do not have a control function, it is possible to establish a residual torque which will meet existing requirements.
A further advantage is that by partially maintaining the complete ratchet function, re-engagement is facilitated thereby in turn reducing the requirements with respect to production tolerances.
In the case of single-row safety clutch, partial omission of the control function is achieved by designing part of the recesses of the clutch sleeve accordingly and, in the case of ratchet rows arranged one behind the other, such partial omission of the control function is achieved by designing the recesses of one or several of the ratchet rows accordingly.
In order to reduce susceptibility to wear and to achieve softer characteristics, it is advantageous to provide the flattened faces of the wedge-shaped head parts with a slightly curved configuration.
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 use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a partial sectional view of a safety clutch in accordance with the present invention shown in torque transmitting condition;
FIG. 2 is a sectional view showing the free wheeling position of a dog member on the left hand side thereof and the starting position for re-engaging into the torque transmitting condition on the right hand side thereof;
FIG. 3 is a sectional view taken through a safety clutch having two control strips in the torque transmitting position arranged on either side of the head part of the dog members with the upper half showing the torque transmitting position and the lower half showing the phase of switching the safety clutch from the free wheeling to the torque transmitting position;
FIG. 4 is a sectional view showing a safety clutch with control strips provided with projections partially extending over the flattened face of the wedged engagement head of the dogs;
FIG. 5 is a sectional view showing half of a safety clutch in a case where the engagement head of the dog members is formed with a slightly curved end face and wherein the control strips have been provided with an extension which at least partially covers the inner annular face of the clutch sleeve;
FIG. 6 is a sectional view through a safety clutch wherein the upper half shows dog members having the function of control cams and the lower half shows dog members having purely the function of working cams;
FIG. 7 is a sectional view illustrating the case where a recess of the clutch sleeve is adapted to the engagement head of a dog member by adjoining filler strips; and
FIG. 8 is a longitudinal section through a ratchet clutch composed of several rows of ratchets.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A clutch assembly which is an example of the present invention is shown in FIG. 1 as comprising a clutch hub 2 which acts as the driving member having on its outer circumference pockets 10 within which dog members 5 are held and loaded radially outwardly by means of a spring 7. A clutch sleeve 1 is rotatably supported relative to the clutch hub 2, with the sleeve 1 being provided with recesses 4 which are distributed across the circumference thereof and which are tapered radially outwardly. The dog members 5 include wedged engagement heads 6 which are adapted to engage within the recesses 4 in order to place the clutch in torque transmitting engagement.
It will be seen that the width, taken in the circumferential direction, of the recesses 4 is greater than the width of the wedged engagement heads 6. Therefore, with the wedged engagement heads 6 in torque transmitting engagement in the recesses 4, a remaining space will exist. This remaining space is filled with control strips which in the representations of FIGS. 1-4 are variously identified by reference numerals 3, 3', 3", and 3'".
In a case where overloading of the clutch develops, the clutch sleeve 1 will be braked or it will be stopped immediately as a result of which the dog members 5 will be drawn out of the recesses 4 moving radially inwardly of the clutch hub 2 because of the wedge shape of the engagment heads 6. The dog members 5 following from the side away from the direction of rotation move the control strips 3 from the side of the recesses 4 away from the direction of rotation to the sides of recesses 4 facing the direction of rotation. Because of the predetermined distance of movement of the control strips 3, the space 8 consequently forming in the recesses 4 on the side away from the direction of rotation is smaller than the flattened faces 9 of the wedged engagement heads 6 of the dog members 5. As a result, the dog members 5 cannot fall into the compensation spaces 8, but move past these spaces.
On the side of the recesses 4 facing the direction of torque transmission, because of the movement of the control strips 3, there is no opening corresponding to the size of the wedged engagement heads 6 but an opening whose width is only slightly greater than the flattened face 9.
Therefore, if the clutch hub 2 continues to rotate a nominal speed, the force applied by spring 7 to the dog members 5 in the direction of engagement is not sufficient to accelerate the dog members 5 to such an extent that they can at least partially fall into the remaining space 12. The safety clutch therefore continues to rotate at a reduced torque.
By reducing the nominal speed, the time which is available for the dog members 5 to fall into the remaining spaces 12 is extended to such an extent that the wedged engagement heads 6 of the dog members 5 can at least partially fall into or catch within the spaces 12. If in the meantime the cause for the overload condition has been removed, the wedged engagement heads 6 of the dog members 5 fall into the recesses 4 of the clutch sleeve 1 while the control strips 3 move against the direction of rotation. The return movement of the control strips 3 is promoted by the rotational vibrations occurring in the drive of the agricultural machinery.
In addition to the spring force acting on the dog members 5, the difference in length between the space 12 and the flattened faces 9 also operates to determine the speed at which the clutch will re-engage for torque transmission.
On the left hand side of FIG. 1, there is illustrated a control strip 3' which projects from the clutch sleeve 1 radially inwardly by a finite dimension. Such a control strip 3' is moved positively by the engagement heads 6 of the dog members 5 from the torque transmitting position into the free wheeling position.
The left hand side of FIG. 2 shows the flattened face 9 of the wedged engagement head 6 moving over the compensation space 8 which is on the side of a recess 4 away from the direction of rotation and which is produced by moving a control strip 3". The control strip 3" which is illustrated on the left hand side of FIG. 2 is formed with a thickness which increases in the direction of rotation and as a result of this, in addition to the friction occurring between the flattened face 9 and the control strips 3", a force component acting in the direction of rotation is applied.
On the right hand side of FIG. 2, there is shown a developed view of the stage of re-engagement of the safety clutch into the torque transmitting position. Due to a reduced speed, the wedged engagement head 6 of the dog member 5 has had an opportunity of catching into the remaining space 12 of the recess 4. As a result, and helped by the existing rotational vibrations, it is capable of moving the control switch 3 against the direction of rotation far enough to enable the wedged head 6 to fall completely into the space 12 of the recess 4.
FIG. 3 shows a safety clutch where each recess 4 in the clutch sleeve on either side of the wedged engagement head 6 of the dog member 5 contains a control strip 3. In the case of this embodiment, the safety clutch is capable of acting in both directions of rotation as an overload ratchet with a reduced free wheeling torque. The upper half of FIG. 3 shows the safety clutch in the torque transmitting position while the lower half illustrates the initial phase of switching of the clutch from the free wheeling position into the torque transmitting position, with the clutch hub rotating in the direction indicated by the arrow.
FIG. 4 shows a safety clutch wherein control strips 3'" have been provided which include projections arranged in the direction of the engagement heads 6 of the dog members 5 and contributing toward determining the distance of movement of the control strips 3'".
In FIG. 5 there is shown a safety clutch which is provided with dog members 5' formed with their flattened faces 9 having a slightly curved configuration.
The thickness of the control strips 3"" illustrated in FIG. 5 taken in the radial direction is greater than the depth of the recesses 4. The control strips 3"" project into an annular space 16 arranged between the clutch sleeve 1 and the clutch hub 2 and in the circumferential direction they are each provided with extensions 14 which extend from the center of recesses 4 and which at least partially cover the inner cylindrical face of the clutch sleeve 1. The length of the extensions in the circumferential direction is designed in such a way that in the switched-off position the space forming between the two extensions 14 is not large enough for the dog members 5 to catch.
FIG. 6 depicts a safety clutch which combines the controlled ratchet function described thus far with a conventional ratchet function.
The upper half of FIG. 6 depicts the controlled ratchet design and the lower half the known uncontrolled ratchet.
FIG. 6 illustrates the principle only and in practice an even distribution of the two functions in the required ratio will be sought to be attained.
FIG. 7 shows a rather economical design for producing a combined safety ratchet wherein the recesses 4 of the clutch sleeve 1 are all produced with the same cross-section and wherein uncontrolled ratchet function is achieved by inserting the corresponding filler strips 15.
FIG. 8 is a longitudinal sectional view through half a multi-row safety clutch in the case of which it is possible to allocate to the individual rows one of the aforementioned functions, depending upon requirements, in order to achieve a desired combination effect.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles. | A clutch particularly suitable for machine drives in agricultural implements including a clutch hub, a clutch sleeve, and spring-loaded dog members operative to engage and disengage within tapered recesses in said clutch sleeve for controlling torque transmission through the clutch. The recesses are formed with a circumferential dimension large enough to accommodate therein movable control members together with engagement heads of the dog members. The control members cooperate with the dog members within the recesses to effect disengagement of the clutch when a maximum torque is exceeded and to automatically effect re-engagement of the clutch upon achievement of a nominal speed whereupon the dog members, which are spring-loaded in the clutch hub, may automatically re-engage within the recesses. | 5 |
RELATED APPLICATIONS
This application is a continuation of Ser. No. 669,174, filed Mar. 22, 1976, now abandoned, which in turn was a continuation of Ser. No. 504,838, filed Sept. 10, 1974, and now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to improved compositions of matter for restoring prepared teeth, which can be easily carved into a replica of the original anatomical form. More particularly, the present invention contemplates compositions of matter comprised of a conventional filler and a polymerizable monomeric substance having two or more polymerizable groups which react at different rates. The polymerizable substance may be comprised of a monomer having within its structure the two or more polymerizable groups, or a mixture of monomers, of different reactivity. Groups are selected having a reactivity such that the compositions will polymerize to achieve a Shore D hardness of about 85 at least in two minutes, but preferably within about twelve minutes, after reaching Shore D hardness of about 45 at 37° C., thus permitting the dentist ample time to shape the restoration using conventional carving techniques.
2. Description of the Prior Art:
Dental amalgam has been used for dental restorations for over a century, and is still used in about three-fourths of all restorations. More recently developed composite restoratives comprised of a filler and a polymerizable monomer, while superior to amalgam in many respects, have replaced amalgam to only a limited extent due at least in part to the difficulty in shaping of these compositions to a replica of the original occlusal surface.
In a Class II cavity preparation, a considerable amount of the occlusal surface is involved along with at least one of the proximal surfaces. It is very important to the proper functioning of the tooth that these surfaces be restored to their original shape. The ridges and fossae of the occlusal surface have been designed by nature to form a mating surface for the opposing tooth. If the occlusion is correct, the wear rate of a restoration is limited. In a restoration which does not have the proper shape, the resulting abnormal stresses can lead to wear facets and pathological changes. Equally important is shaping the proximal surface of a restoration in order to achieve proper contact with adjacent tooth. Thus, the dentist, when placing an amalgam filling, will spend a considerable time carving and fitting the restoration. Since amalgam is easily workable for about six minutes after being packed into the tooth cavity, there is adequate time for the dentist to complete his work. On the other hand, prior art composite restorative materials have exhibited such a short time between the soft set and the hard set stage, i.e., five to thirty seconds, that the necessary hand carving and fitting is practically impossible. This disadvantage cannot be overcome by shaping of the composition after it has reached the hard set stage with the use of a drill because of difficulties in operation with extremely hard material in interproximal areas, and lack of precision.
SUMMARY OF THE INVENTION
The present invention overcomes the disadvantages of prior art composite compositions by providing composite restorative material which reaches a hard set stage a sufficient period of time after reaching the soft set stage to afford the dentist adequate time for carving and fitting of the restoration, without sacrificing the advantages of existing composite restorative materials, i.e., good marginal adaptation, high mechanical strength, aesthetics, good wear resistance, and low thermal conductivity. Furthermore, the present objectives are obtained without a concomitant lengthening of the gel period of the composition, thus avoiding inconvenience to the patient and time loss to the dentist.
More specifically, the present invention is directed to providing dental restorative compositions comprised of a conventional filler in combination with a polymerizable material consisting of at least two polymerizable groups of different reactivity. The polymerizable substance may be comprised of a bi- or poly-functional monomer having the two or more polymerizable groups within its structure, or may be comprised of a mixture of at least two monomers each containing a polymerizable group having a reactivity different from the polymerizable group on the other monomer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Dental restorative compositions of the type described in detail hereinafter are normally supplied to the dentist in two separate portions, one of these portions containing a catalyst and the other portion containing an activator for the catalyst. In using the material, the dentist mixes the two portions to form the active composition. The dentist places the freshly prepared mix into the prepared tooth cavity. Continuing polymerization of the composition causes the composition to cure to a hardness sufficient to permit carving by the dentist shortly after placing of the composition into the tooth cavity. At this stage, the composition will have a Shore D hardness of about 45 and is sufficiently hard for the dentist to carve. The mixture will continue to further polymerize, gradually becoming harder over a period of time, e.g., about six minutes, at the end of which it will reach a Shore D hardness of 85 after which it cannot be carved easily. At this stage, the composition is sufficiently hard to permit release of the patient.
The polymerizable substances of the above composition, in order to obtain the desired results of the present invention, include at least two polymerizable groups having different reactivity rates under the conditions of polymerization employed. It is not essential, however, that the two groups be of different chemical structure, since, as is well known by the skilled artisan, the reactivity of groups of the same chemical structure may be varied by the location of the groups within the structure of the compound. While the polymerizable substance of the present invention may be comprised of a single monomer or prepolymer having within its structure at least two groups having different reactivity, polymeric substances comprised of at least two monomers each of which has a group exhibiting a reactive rate different from the group of the other monomer, may also be employed.
Exemplary of monomers containing at least two groups of different reactivity are: allyl methacrylate, allyl acrylate, allyl glycidyl ether, diallyl fumarate, diallyl maleate, glycidyl methacrylate, butene-1, 4-dimethacrylate, butene-1,4-diacrylate, 4-hydroxy butene methacrylate, 4-hydroxy butene acrylate, and 1-methacryloyl-2-acryloyl-propane. Other suitable compounds will be readily apparent to the skilled artisan. With these monomers, it is possible to form compositions using only the single monomer or to use the monomer in admixture with other monomers such as the mono or diacrylates or methacrylates, for example, 2,2-bis[4'(-3"-methacryloyl-2"-hydroxy propoxy)phenyl]propane (known as Bis/GMA), polyethylene glycol dimethacrylate, cyclohexyl methacrylate, and mixture thereof.
Instead of employing a bifunctional monomer or prepolymer, it is, as aforementioned, possible to employ two monomers containing functional groups of different reactivity. These monomers may, for example be selected from the following compounds: diglycidyl ether of bisphenol A, diallyl phthalate, mono-, di- or polyethylene or polypropylene glycol dimethacrylate, methyl methacrylate, Bis/GMA, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, ethyl methacrylate, ethyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, diallyl methacrylate, diallyl acrylate, 2-aminoethyl methacrylate, 2-aminoethyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetra-ethylene glycol diacrylate, styrene, and triallyl cyanurate.
Suitable polymerizable substance may contain at least two polymerizable groups selected from vinyl, allyl, acryl, methacryl and styryl groups such that the composition upon polymerization would reach a Shore D hardness of about 85 at least about two minutes, and preferably about four minutes, after the composition reaches a Shore D hardness of 45 in order to afford the dentist adequate time for hand carving of the composition. Desirably, reactive groups and conditions will be selected so that the composition will reach the gel state within about two minutes after initiation of the polymerization, and a Shore D hardness of about 45 within about four minutes after initiation of the polymerization.
The fillers forming a part of the present composition are of a conventional nature and are well known within the prior art as exemplified by U.S. Pat. Nos. 3,539,533 and 3,751,399 to Lee et al. These fillers include quartz, glass, silica and various silicates which generally have a particle size from about 0.5 to about 85 microns and preferably from about 1 to about 75 microns. The compositions described herein will normally be comprised of from about 50 to about 80 percent by weight of said filler.
The compositions of the present invention may also contain other conventional additives such as curing agents, polymerization catalysts, inhibitors, antioxidants, dyes, ultraviolet absorbers, preservatives, and the like. The particular catalyst employed will depend upon the types of monomers or prepolymers comprising the composition and will be apparent to the skilled artisan.
The following examples are illustrative of the present invention and are not to be taken in limitations thereof. In each of the examples, Part A was admixed with Part B to initiate the polymerization reaction. The times necessary to reach a Shore D hardness of 45, permitting hand carving, as well as the time over which hand carving was possible, i.e., the time until the composition reached a Shore D hardness of about 85, were determined.
EXAMPLE 1
______________________________________Allyl methacrylate 4.0 (g)Bis-GMA 16.0 (g)N,N-bis(2-hydroxyethyl)-p-toluidine 0.026 (g) Part A2-Hydroxy-4-methoxy benzophenone 0.112 (g)2-Isobutyl-4-hydroxytoluene 0.012 (g)Silica 76.7 (g)Benzoyl peroxide 0.3 (g) Part Bα-Methacrylpropyl trihydroxysilane 2.7 (g)______________________________________
The mix reached a Shore D hardness of 45 in three minutes at temperature of human body of 37° C., and remained easily carvable for about four minutes more. After 24 hours cure at 37° C., the compressive strength was 41,700 psi and hardness (Rockwell H) 114.
EXAMPLE 2
______________________________________Allyl methacrylate 8.0 (g)Bis/GMA 12.0 (g)N,N-bis(2-hydroxyethyl)-p-toluidine 0.026 (g) Part A2-Hydroxy-4-methoxy benzophenone 0.112 (g)2-Isobutyl-4-hydroxy toluene 0.012 (g)Silica 76.7 (g)α-Methacrylpropyl trihydroxysilane 2.7 (g) Part BBenzoyl peroxide 0.3 (g)______________________________________
The mixture, at the temperature of the human body of 37° C., reached a Shore D hardness of 45 in approximately two minutes; hand carving time was about three minutes. After 24 hours cure at 37° C., the compressive strength was 45,733 psi and hardness (Rockwell H) 114.
EXAMPLE 3
______________________________________Allyl glycidyl ether 8.0 (g)Bis/GMA 12.3 (g)Diethylenetriamine ethylene oxide adduct 0.65 (g) PartN,N-bis(2-hydroxyethyl)-p-toluidine 0.026 (g) A2-Isobutyl-4-hydroxy toluene 0.0152 (g)Silica 78.0 (g)α-Glycidoxypropyl trihydroxysilane 3.0 (g) PartBenzoyl peroxide 0.3 (g) B______________________________________
The A and B components were mixed in a 1:3.5 ratio. The mix reached a Shore D hardness of 45 in three minutes at room temperature and was, thereafter, hand carvable at temperature of human body of 37° C. for four minutes. After 24 hours cure at 37° C., the compressive strength was 27,600 psi and hardness (Rockwell H) 113.
EXAMPLE 4
______________________________________Glycidyl methacrylate 10.0 g)Allyl methacrylate 10.0 g)N,N-bis(2-hydroxyethyl)-p-toluidine 0.12 g) Part A2-Isobutyl-4-hydroxytoluene 0.012 g)Silica 78.0 g)α-Glycidoxypropyl trihydroxysilane 2.56 g) Part BBenzoyl peroxide .19 g)______________________________________
The mixture of Parts A and B reached a Shore D hardness of 45 in about seven minutes at room temperature. Transferred to 37° C., it reached a Shore D hardness of 85 after five minutes. After a two-hour cure at 37° C., its compressive strength was 37,400 psi.
EXAMPLE 5
______________________________________Bis/GMA 10.6 g)Cyclohexyl methacrylate 10.6 g) Part AN,N-bis(2-hydroxyethyl)-p-toluidine .065 g)2-t-butyl-5-hydroxy toluene 0.012 g)Silica 76.0 g)α-Glycidoxypropyl trihydroxysilane 2.5 g) Part BBenzoyl peroxide .19 g)______________________________________
The mix of Parts A and B reached a Shore D hardness of 45 in 7.5 minutes at room temperature. Transferred to 37° C., it reached a Shore D hardness of 85 in 10 minutes. After a two-hour cure at 37° C., its compressive strength was 29,000 psi.
EXAMPLE 6
______________________________________Bis/GMA 11.4 g)Diallyl phthalate 11.4 g) Part AN,N-bis(2-hydroxyethyl)p-toluidine 0.07 g)2-Isobutyl-4-hydroxy toluene 0.012 g)Silica 75.0 g)α-Glycidoxypropyl trihydroxysilane 2.5 g) Part BBenzoyl peroxide .19 g)______________________________________
The mix of parts A and B reached a Shore D hardness of 45 in about two minutes at room temperature and a Shore D hardness of 85 in seven minutes, after transferring to temperature of 37° C. After a two-hour cure at 37° C., its compressive strength was 27,000 psi.
It will be understood that many modifications and variations of the present invention may be made without departing from the spirit and scope thereof. | Dental restorative compositions comprise self-curing systems of monomer containing two or more polymerizable ethylenically unsaturated groups of different respective reactivities, and thus of different curing rates, and other materials such as fillers, inhibitors, curing agents, and the like. The polymerizable groups may be selected from the group consisting of two or more vinyl, allyl, acryl, methacryl, and styryl groups. | 0 |
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a device for the treatment of materials; and more particularly, it concerns a novel device having a heating chamber which is selectively opened and closed by a door.
DESCRIPTION OF THE RELATED ART
Devices of this kind are employed for initiating, promoting and/or carrying through chemical or physical processes in materials and/or for the preparation of materials in each case with relatively great heating and/or simply for the heating of materials for various purposes.
Thereby, there may be involved measures for separation of materials and/or preparation of materials in particular for the purpose of analysis and/or for the preparation of materials, e.g. heating or baking of foodstuffs for consumption.
With the above-described measures, because of the effect of the heat and evaporation of the material to be heated or of components of the material there is a pressure increase in the heating chamber which in particular in the case of a large volume heating chamber and a large area closure element can lead to an overloading and thus damaging of the parts retaining the closure element in its closure position. With a pressure increase in the heating chamber of only about 0.5 bar, there is in the case of a charging aperture of about 40 cm×40 cm a pressure loading of 800 kg on the inner surface of the closure element. Conventional mounting constructions for the closure element are not designed for such a loading. Such a design would also make more difficult the integration of the mounting elements and further lead to a disadvantageous and costly construction.
The above-described problems are present both when the material is treated in special closable sample containers or is treated directly in the heating chamber. In the first case, because of the pressure increase, there often occurs a bursting or exploding of the sample container or containers, whereby the pressure propagates into the heating chamber and places this likewise under pressure. In such devices or treatments in which the material to be treated is placed directly into the heating chamber, the latter is directly set under pressure.
The above-described problems occur with devices of the present kind in the case both of commercial use and also domestic use. An example of a domestically useable device is e.g. a domestic microwave oven which likewise suffers the above-described disadvantages and is also at risk for the above-mentioned reasons.
SUMMARY OF THE INVENTION
The object of the invention is to protect a device of the kind indicated in the introduction from an overloading resulting from a damaging internal pressure.
All solutions in accordance with the invention contribute to the protection of the device from overloading and thus contribute to a protection from explosions.
According to one aspect of this invention, there is provided a device for the treatment of materials under the action of heat, and if appropriate, also pressure, in a heating chamber. The device is formed with a charging aperture which opens into the heating chamber; and this aperture can be selectively opened and closed by means of a door which normally presses against a frame around the aperture. A heating device, such as a microwave generator, is provided for the heating chamber. The door is so mounted that upon a particular pressure in the heating chamber being exceeded, the door lifts off from the frame and moves to a relief-opened position; and, after the reduction of pressure, the door can be moved back into the original position either automatically or by the application of force.
With the above described configuration in accordance with the invention, an overpressure in the heating chamber is automatically released, so that overloading cannot arise. The door, standing in its relief position, can thereby fulfil a monitoring or indicating function from which it is apparent to the operating person that an overpressure was present.
Thereby, a maximum loading of the device or of the door can be limited by means of the force of a spring which biases the door into its closed position. In the case of an internal pressure exceeding the thereby predetermined pressure parameter, the door is moved against the biasing force of the spring, whereby an opening gap appears through which the pressure can escape, whereby the overloading is prevented. With such a configuration working can take place with an overpressure in the heating chamber which is lesser than the bias force.
According to a specific embodiment of the invention, the housing has a set of perforations, whereby an overpressure is prevented from arising, since the overpressure can escape through the perforations. This configuration in accordance with the invention is suitable for measures for the heat treatment of materials which take place at normal pressure or room pressure and/or at an under-pressure in the heating chamber.
According to a further specific embodiment of the invention, a pressure sensor is associated with the heating chamber which together with a control or regulation device reduces or so controls the heating power that a particular internal temperature is not exceeded or the heating is turned off. In all these cases, the internal temperature is limited or reduced so that through these means a damaging or dangerous increase in the internal pressure is avoided. This configuration in accordance with the invention is suitable in particular for combination with the configuration in accordance with the invention in particular when the heating device is a microwave heating device. With such a combination, the movable closure element may be the pressure sensitive part of the pressure sensor which brings about a switching off of the microwave power. By these means, not only is the temperature in the chamber reduced but it is also prevented that microwaves escape to the outside through the gap formed upon movement of the closure element between the latter and the housing.
Additional specific features of the invention as embodied herein involve features which improve the functions of the device or the mounting of the closure element and provide for simple, compact and economically manufacturable constructions which also make possible a purposive treatment and special treatments of the material.
BRIEF DESCRIPTION OF THE DRAWINGS
Below, the invention and further advantages which can be achieved thereby will be described in more detail with reference to preferred exemplary embodiments as shown in the accompanying drawings in which:
FIG. 1 is a perspective view showing a device in accordance with the invention and, in particular, showing a door in a first position;
FIG. 2 is a view similar to FIG. 1 but showing the door in a second position; is a view similar to FIG. 1 but showing the door in a second position.
FIG. 3 is a fragmentary section view showing one form of door mounting arrangement for the embodiment of FIG. 1;
FIG. 4 is a fragmentary section view showing a door locking arrangement for the device of FIG. 1; and
FIG. 5 is a front elevational view, partially cut away, of a housing for the device of FIG. 1, with the door removed;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIGS. 1 and 5, a device 1 according to the present invention, comprises; a block-like housing 2 having a front charging aperture 3 (FIG. 5) which can be selectively opened or closed by means of a swing door 4, elastically yielding mounts 5 for the swing door 4, a heating device 6, in particular a microwave heating device, for heating a heating chamber 7 arranged in the housing 2, and an electrical control and/or regulation device 8 which is connected with the associated control or regulation elements of the device 1 by means of control or signal lines and is equipped with automatically functioning control and regulation elements and, if appropriate, with a keyboard for manual setting.
The housing 2 is of block-like form and has a floor wall 9, two side walls 11a, 11b, a ceiling wall 12 and a rear wall 13, whereby the front wall is formed by means of the swing door 4 and closes the front charging aperture 3 in its closed position.
As shown in FIG. 1, there is provided a heating device 6. The heating device 6 has a magnetron, which may be arranged e.g. over an opening on the ceiling wall 12 (not shown) and through which the microwaves are coupled into the heating chamber 7. The housing 2 is of metal, whereby the swing door 4 may also be partly of transparent material, e.g. glass. In this case it is however prevented, by measures known per se (metal grids), that microwaves can emerge through the glass.
In the present configuration, the swing door 4 is mounted swingably by means of two yielding joint mounts 5, arranged at the upper and lower corner regions, respectively, at one side; and the door 4 is closable by means of a locking device 14 arranged on the other side. The locking device 14 has an externally accessible handle 14a and a vertically movable key bolt 14b (shown in FIG. 4) connected therewith in conventional manner. The overall two yielding joint mounts 5 is essentially the same, except that they are arranged in a mirror-image manner with regard to a horizontal middle plane. For purposes of simplicity, therefore, only the upper yielding joint mount 5 will be described.
The joint 16 of the yielding joint mount 5 consists of a joint part associated with the housing 2 in the form of a joint bar 17 preferably circular in cross-section which extends at right angles to the plane of the door 4 and which is guided and mounted in a guide hole 18 of a mounting piece 19 displaceably along its middle axis, i.e. likewise at right angles to the plane of the door. The joint bar 17 penetrates the mounting piece 19 and projects beyond it to the rear, whereby a compression spring 22 is spanned between a thickened bar head 21 and the mounting piece 19, which (biases) the joint bar 17 to the rear against a stop 23 which may advantageously be formed by means of a stop piece attached on the housing 2 behind the bar head, here on the ceiling wall 12 of the housing.
The joint bar 17 extends forwardly beyond the plane of the charging aperture 3 (FIG. 5) and engages into a horizontal joint recess 24 (FIG. 3) of the swing door 4, with play for movement. Within the swing door 4, the joint bar 17 has a vertical joint bore 25 in which a joint pin 26 is mounted with play for movement, which joint pin is held on the swing door 4. The joint recess 24 is so large horizontally that the swing door 4 can be swung more than 90°, whereby the door is mounted with the horizontal limiting walls of the joint recess 24 on the two joint bars 17 present. The stop or stops 23 are so positioned that with abutment of the bar head or heads 21 due to the biasing of the spring 22, the swing door 4 abuts with its abutment surface 20a on the abutment surfaces 20b surrounding the charging aperture 3, if appropriate by means of a seal (not shown) and thereby closes the heating chamber 7. The later abutment surface 20b may also be arranged on a flange 2a surrounding the charging aperture 3.
Preferably the yielding joint mount 5 is integrated in an adjustment device designated generally with 28 which makes possible an adjustment and setting of the swing door 4 at right angles to its plane, in order to adapt the door to the abutment surface 20b taking into consideration the tolerances present. With the present configuration, the adjustment device 28 is formed by means of a telescopable joint rod 17 whereby its rear end region has a thread onto which there is screwed a threaded nut 29--preferably lockably on the thread--which slightly projects beyond the rear end of the joint rod 17 and is thus suitable for length setting. A yielding mount 5a is provided in the region of the locking device 14 is formed in substance the same as the yielding mount 5 in the region of the joint 16--see the same parts with the same reference numbers--whereby however instead of a joint 16 at the forward end of the locking bar 17a there is provided a locking recess 31, if appropriate with an approach slant 31a of the thus formed locking part. The locking bar 17a is adjustable in the same manner as the joint bar 17. There is to be associated with the locking bar 17a, so far as it is circular, a means preventing rotation thereof, since it is not secured against rotation as is the joint bar 17 by means of the joint pin 26 in the door.
With the above-described configuration, the yielding joint mounts are arranged on the ceiling wall 12 or under the floor wall 9 and attached thereto, and the yielding locking device 14 is mounted on the outside on the associated side wall 11b. Within the scope of the invention, however, other arrangements are possible, e.g. the two joint mounts 5 may be mounted on the inside or the outside on the associated side wall 11a or integrated therein.
Within the scope of the invention it is possible to correspondingly retain and mount a lid (not shown) or a swing door arranged on the upper side (not shown).
For a heat treatment process of a material this is placed, preferably in at least one receptacle A (FIG. 5), in the heating chamber 7 and the heating device switched on, whereby the material is heated by means of the microwaves directly or also indirectly, as is known per se. Vapours thereby appearing, and temperature and/or pressure rises connected therewith, can increase to such a level in the heating chamber 7 that the compression springs 22--dimensioned in accordance with a particular pressure value and exercising a corresponding bias--are overcome and the swing door 4 lifted off from the abutment surface 20b. Hereby, there arises a gap S illustrated in FIG. 2, through which an overpressure exceeding a predetermined pressure value can escape to the outside. By these means, the loading of the spring door 4 and its mounting and locking means is limited to a value so that these parts, with regard to their strength, need only be made so robust that they can accept the demands at the predetermined pressure value. This applies naturally also for the housing 2, because a higher internal pressure cannot arise.
It is also advantageous to associate with the heating chamber 7 a pressure sensor which monitors the internal pressure and at an internal pressure which may be equal to the predetermined pressure value or may also correspond to a lesser pressure value, switches off the heating device 6 and in particular a microwave heating device, so that no microwaves can escape to the outside through the gap S.
The gap S preferably in the range of 1 to 5 mm.
An above-mentioned pressure sensor may in advantageous manner monitor the position of the swing door or components mounted on the same; and, in the event of a movement, the pressure sensor may deliver a signal to the control device 8 (FIG. 1). With the present configuration, two pressure sensors are formed by means of switches or microswitches 33 which are preferably arranged between the stop pieces 23--in particular therein or thereon built-in or built-on--and the rearward ends of the joint rods 17 and deliver a signal upon lifting off of the swing door 4.
The parts of the yielding joint mount 5 and locking mount 5a may be of metal.
As shown in FIG. 5, with the above-described exemplary embodiments, instead of or in addition to the elastically yielding door mount, there may be provided in a wall or in one or in both side walls 11a, 11b, a set of perforations 35 in a part region 36 of the associated wall. The part region 36 is located preferably in the lower region of the housing. The set of perforations comprises a plurality of holes 37 the cross-sectional size of which is so large--taking into consideration the wall thickness and the wavelength of the microwaves--that no microwaves emerge from the holes 37. In the present configuration, circular holes are provided, the cross-sectional size or diameter of which is 2 to 4 mm. The thickness of the side wall 11a and also 11b may thereby be about 1 mm.
The number of the holes 37 is such that, in the case of a spontaneous pressure increase to be expected, the pressure can escape through the holes 37 without the device 1 suffering damage or exceeding a particular pressure value. With this configuration, a treatment of the material in the heating chamber 7 is in substance possible only at normal or room pressure.
The perforations 35 are, however, also suitable advantageously in combination with an elastically yieldingly held swing door 4 when the perforations are only so large that despite the perforations there can arise in the heating chamber 7 a pressure exceeding the predetermined pressure value which brings about the abovedescribed lifting off of the door.
The perforations 35 may also be a part of a ventilation system 38 for heating chamber 7. In this case, there is provided at another location of the housing 2, preferably an opposite location, e.g. in the other side wall 11b, a second set of perforations 35a in a corresponding manner, whereby one of the sets of perforations--here the perforations 35a--is provided at a suction or pressure device for air or a gas, e.g. an inert gas. In accordance with FIG. 5, the perforations 35a are connected by means of a collector 39 and a connected pipe or tube line 41 with a pump 42 which transports the air or a gas from a gas source through the heating chamber 7 by suction or pressurisation. Here, a cooling and/or flushing device for the heating chamber 7 may be involved. In particular in the case of a flushing device for transporting away vapours out of the heating chamber 7 it is advantageous to connect the discharge line to a chimney or to a device for analyzing the vapours.
With the configuration according to FIG. 5, one or more receptacles A may be provided which are each sealingly closable by means of a receptacle lid A1 and with each of which an over-pressure valve V is associated which opens at a receptacle pressure exceeding a predetermined value. Preferably, the associated valve body is the receptacle lid A1 itself which is biased into its closed position by means of a spring element V1, e.g. by means of a settable pressure part, preferably in the form of a setting screw V2.
With the configuration according to FIG. 5, there is provided a carousel 45 having a carrier disk 45a and a cover disk 45b, rotatable or swingable to and fro by means of a drive (not shown), whereby the setting screws V2 are vertically screwed into and preferably accessible from above the cover disk 45b. The receptacles A, with the spring element V1 preferably arranged thereon, are mounted between the setting screws V2 and the current disk 45a. | In a device (1) for the treatment of materials under the action of heat, and if appropriate also pressure, in a heating chamber consisting of a housing (2), containing the heating chamber, having a charging opening for the heating chamber which can be selectively opened or closed by means of a door (4), and a heating device (6), in particular a microwave heating device, for the heating chamber (7), the door (4) is so mounted that when a particular pressure in the heating chamber is exceeded it lifts off from the door frame (2) and is movable into a relief-opening position, out of which position it is moveable back into the original-closed position--after reduction of pressure--either automatically or by the application of force. | 4 |
BACKGROUND OF INVENTION
This invention relates to an improved pivotal connection between the narrow slats which form an accordion-type folding shutter which substantially increases the resistance to slat separation caused by impacts against the shutter.
Conventional accordion-type folding shutters generally comprise numerous, vertically arranged, narrow slats which are pivotly connected together along their adjacent edges. The shutters may be extended or unfolded to overlay or cover an opening formed in a building, such as a window or door opening. Alternatively, the shutter may be folded so that its slats are compressed together to clear the opening. Normally, the shutters are extended for the purpose of protecting against intrusion or penetration through the building opening. Therefore, the shutters must be made in such a manner as to resist the forces that are applied by the impact of wind-hurled objects or manually applied objects.
Since conventional shutters are typically connected together by tube-like connector formations formed on the opposite edges of the respective slats, with one formation or member being sized to fit within and to pivot within the adjacent member, substantial impact forces can break apart or separate adjacent slats at their connections. Thus, conventional shutters are vulnerable to penetration or slat separation due to relatively strongly applied impacts against the pivotal connections between their adjacent slats.
Examples of such types of accordion folding shutters and of the connections between their adjacent slats are disclosed in U.S. Pat. No. 3,670,797 issued Jun. 20, 1972 to Sassano (e.g., see FIGS. 4 and 5 of the drawings) and U.S. Pat. No. 5,097,883 issued Mar. 24, 1992 to Robinson et al. (e.g., see FIGS. 8, 10 and 11).
In U.S. Pat. No. 3,670,797, an inner, tubular-like pivot member (e.g., see, FIG. 5) having a substantially greater wall thickness than the remainder of the slat, fits within an outer pivot member. The outer tubular-like member is provided with inwardly extending edge beads along the edges which define a slot through which a bent edge of the slat is fitted for integral connection with the inner tube-like member. Although, those beads assist in spacing the outer surface of the inner member from the inner surface of the outer member, they tend to axially mis-align the inner and outer members, particularly during folding and unfolding of the shutters.
The pivotal connection system disclosed in U.S. Pat. No. 5,097,883, includes an inner tube-like member on one slat fitted within an outer tube-like member on the next slat. The inner member is connected, through a short, angularly bent-edge portion, to its respective slat. Each of the inner and outer members is provided with an elongated slot. The edges of the outer member slots have inwardly extending beads. The edge of the inner member slots have outwardly extending beads (e.g., see FIGS. 10 and 11). However, those bead constructions limit the angle between adjacent slats to approximately 60 degrees when the shutter is extended. Hence, a considerable number of slats are required to cover a given lineal distance. That construction, also, tends to require relatively wide and thick slats and have a limited resistance to separation of the slat connections under impact.
The present invention relates to an improved pivotal connection which substantially increases the separation and penetration resistance of the slat connections and permits the use of thinner, relatively narrower slats which extend apart at a considerable angle as compared with the abovedescribed shutters.
SUMMARY OF INVENTION
This invention relates to an improved, substantially rigidified, separation resistant, pivotal connection between slats used in accordion-type foldable shutters. Such shutters comprise vertically arranged, elongated, narrow, thin slats which are joined together, edge-to-edge, by a hinge-forming arrangement by which the shutter may be extended for covering a building opening or may be folded to clear the opening. The connection is provided by integrally forming pivotally interfitted tube-like members upon the opposite elongated edges of the slats. One tube-like member is of a smaller diameter than the other member so that the smaller diameter member may be co-axially positioned within the outer, larger member of the next slat for pivoting therein.
The outer, tube-like member, is formed in a generally circular cross-sectional shape with a slot which spans roughly a third of the circumference of the member. The edges which define the slot are formed with radially inwardly directed beads. The smaller or inner tube-like member of the next slat, is co-axially arranged within the outer member and is connected, by a narrow bent-edge strip to the slat. The narrow strip extends through the slot in the outer member. Thus, the inner member may be pivoted relative to its respective outer member along an arc equal to the width of the slot in the outer member.
The inner, tube-like member, is also provided with a slot extending along its length and the edges of the material defining that slot are provided with radially outwardly extending integral beads. These are positioned to swing within the inner wall surface of the outer tube-like member.
The vertical edge of the slat is connected to its outer tube-like member along a plane which is tangent to the outer member along a line which is slightly angularly offset from a plane which diametrically bisects the outer member. Also, one bead of the outer member is arranged to engage against the bent strip to form a stop which angles the respective slats, when the shutter is extended, through an angle of about 90 degrees. The other bead of the outer member is positioned to engage the opposite side of the strip when the slats are folded together and, in addition, to engage the outwardly extending bead of the inner member when the slats are arranged in their 90 degree angle position. In such angled position, the inwardly extending bead of the outer member and the outwardly extending bead of the inner member jointly form a reinforced column-like strip extending vertically along the length of the connection for reinforcing the connection and for locking the connector members against separation under impact. The second, outwardly extending bead on the inner member normally positions the surface of the inner member away from the inner surface of the outer member.
The foregoing connector arrangement provides a vertically arranged, tube-like construction at the intersection of each of the slats which make up the shutter. The slats may be made narrower than conventional so that there are more of these vertically extending, tube-like strips along the full extended width of the shutter. Nevertheless, even where the slats are narrower, because of the wider angle, i.e. about 90 degrees, attainable when the slats are extended, it is possible to use of the same or even fewer slats than might otherwise be required in the type of connections described in the above-mentioned prior patents.
An overall object of this invention is to provide a system for dissipating the forces relating from manually applied impacts or the impacts of wind-hurled objects, such as debris hurled by hurricane winds. The forces are absorbed by successively crushing the impacted portion of the connector outer member inwardly towards and against the inner connector member and then successively crushing both members together and, forcing the inter-engaged beads more tightly together which simultaneously resists separation of the members. In addition, the forces are partially dissipated through the adjacent angularly arranged slats.
A further object of this invention is to provide pivotal joints or connections between the adjacent slats of a folding-type shutter which connections absorb substantially greater forces of applied impacts and more effectively resist separation of adjacent slats at their connections than prior slat connections.
Another object of this invention is to provide an inexpensive pivotal interconnection between adjacent slats of a folding shutter which provides considerably greater, resistance to impacts to while permitting the use of relatively thinner, narrower and lighter weight slats than what might otherwise be required for equivalent protection.
Still a further object of this invention is to provide an improved pivotal hinge-like joint for the slats of a folding shutter which enable the use of narrower slats which cover a greater lineal distance when the shutter is unfolded, to thereby increase the number of reinforcing joint constructions in the shutter.
These and other objects and advantages of this invention will become apparent upon reading the following description, of which the attached drawings form a part.
DESCRIPTION OF DRAWINGS
FIG. 1 schematically illustrates, in side elevation view, a shutter mounted upon the wall of a building for covering an opening therein.
FIG. 2 is a schematic, front elevational view, of the shutter covering the opening.
FIG. 3 is a schematic, perspective view, showing the shutter extended into its covering position.
FIG. 4 is a plane view, to an enlarged scale, of a portion of the shutter shown in extended or unfolded position for covering an opening.
FIG. 5 is a plane view, showing the shutter in its folded or compressed condition for uncovering an opening.
FIG. 6 is an enlarged, fragmentary view, of a portion of the connection between adjacent slats and illustrating a shutter connection pin for securing the shutter to a support track, with the pin separated from the connection for illustration purposes.
FIG. 7 is an enlarged, plan view, of a single slat.
FIG. 8 is an enlarge, plan view, of the pivotal connection between adjacent ends of a pair of slats, with the slats shown in folded condition.
FIG. 9 is a view of similar to FIG. 8, showing the adjacent slats pivoted into their shutter unfolded or covering position.
FIG. 10 is an enlarged, plan view, showing the connections between adjacent slats and schematically illustrating the application of the forces of an impact upon a slat connection and adjacent slats.
FIG. 11 is a view similar to FIG. 10, showing the effect of applied forces upon the slat connections.
FIG. 12 is a view similar to FIG. 11, illustrating the effect of the application of greater forces upon the connection of adjacent slats.
DETAILED DESCRIPTION
FIGS. 1-3 illustrate an accordion-type folding shutter 10 which is formed of numerous, identical narrow, substantially flat, elongated vertical slats 11. The adjacent edges of the slats are pivotally connected together by tube-like pivotal connections 12 which will be described in detail later. The arrangements of the shutter, slats and their connections are conventional and, therefore, are schematically described. The invention herein relates to the specific construction of the connections which, otherwise, are used in conventional shutter constructions.
Accordion-fold shutter slats typically are formed of extruded metal, such as aluminum, or extruded plastic. The interconnected slats form the shutter which is arranged to cover, when the shutter is extended or unfolded, an opening 14 in a building wall. The opening may be a window, a door, or an open doorway or the like, formed in the wall of a building 15.
Referring to FIG. 1, the shutter is mounted from an upper, header track 17 which, for example, may be formed of extruded aluminum material. The track comprises an inverted, open channel 18 with inner, side channels 19. An integral side flange 20 may be attached to the building structure by screws 21 or other suitable fasteners. In addition, the track may include an outwardly extending guide flange 22 which will cover the upper end of the shutter, as illustrated in FIG. 1.
A lower sill or threshold track 25 is mounted beneath, and in alignment with, the upper header track. The sill track may be formed of an extruded material, such as of aluminum, into the shape of an upwardly opening channel 26. An integral mounting flange 27 is shaped for application against the adjacent building structure and may be secured thereto by means of screws or similar mechanical fasteners 28. The sill track may include an outwardly extending bottom plate or strip 29 which terminates in a downwardly extending trim flange 30.
The cross-sectional shapes of the header track and the sill track may be varied considerably and, therefore, the foregoing description should be viewed as illustrative of a conventional form of mounting a foldable shutter, in this instance, across a window opening in a building wall.
An upper pin 33 is secured to every other slat pivotal connection, as shown in FIG. 3. The upper pin may be connected to a bracket 34 (see FIG. 1) which is generally inverted U-shaped in cross-section. An axle 35 extends through or is fastened to the depending legs of the bracket and wheels 36 are secured upon the opposite ends of the axle. These wheels rotatably fit within the side channels 19 in the upper, header track. Thus, the wheels, the bracket to which the wheels are attached, the upper pins and, consequently, the upper ends of alternating connections between the slats are movable longitudinally along the length of the upper track 17.
The upper pins may include a suitable, washer or ring-shaped flange 38 which engages the upper ends of their respective slat connections. The lower ends 39 of each pin 33 are fastened within their respective connections 12 in any suitable manner, as for example, by forming the lower ends of the pins with a self-tapping thread which will threadedly fit within and engage the surrounding surfaces of the adjacent wall of the connections. The manner of securing such pins within their connections is conventional.
A lower pin 40 is secured within the lower ends of each alternating slat connection, as illustrated in FIG. 3. Each lower pin has an upper end 41 which is fastened within its respective connection. The connection may be made by forming the upper end of the pin with a self-tapping thread for threadedly engaging and connecting with its respective pivotal connection. The manner of securing the lower pins in place is conventional and, therefore, no further description is given here. The lower end 42 of each lower pin slideably fits within the channel 26 in the lower or sill track 25 for slideable movement along the length of that track. A stop collar or washer 43 fastened upon each pin is arranged to engage the lower track, spanning the open mouth of the upwardly opening channel 26 to appropriately position the slat connections above the lower track. Other suitable mechanical means may be utilized, as is conventional in accordion-type folding shutter constructions.
As illustrated in FIG. 7, each slat 11 is formed of a generally flat, vertically elongated, narrow body portion or member 50. An outer, tube-like connection member 51 is integrally formed on one elongated edge of the body member. Similarly, an inner, tube-like connector member 52 is integrally formed on the opposite edge of each body member. The inner connector members are integral with a bent-edge strip 53 which is formed on the body member. The bent-edge strip 53 is preferably arranged at an obtuse angle relative to the plane of the slat body member 50.
The body member is arranged tangent to the outer connector member 51 and is integral therewith along a line 55 which is offset, roughly 30 degrees in a circumferential direction, from the plane which bisects the outer connector member. The degree of offset may varied, but, as illustrated in the drawings of FIGS. 7-9, the generally flat body portion of the slat is substantially tangent to the periphery of the outer connection member.
The outer connection member is provided with a continuous, elongated slot 56. The slot forms an arc "a" which is nearly, about 1/3rd of the circumference of the generally circular cross-section of the outer connector member.
A radially inwardly extending first bead 57 is formed on one of the edges defining the slot 56. The opposite side edges 58 and 59 of the bead are substantially aligned radially with the center of the connector. A second bead 60 is integrally formed with the opposite edge defining the slot 56 and, similarly, its opposite edges 61 and 62 are substantially radially aligned with the center of the connector member. Preferably, the bead 57 is longer, in the circumferential direction, than the bead 60. This is illustrated by showing the arc "b" of the bead 56 being visually larger than the arc "c" of the second bead 60.
The inner tube-like connector member 52 of each slat is provided with a continuous, elongated slot 65 which spans approximately 1/4 of the circumference of the substantially circular, in cross-section, connector. The arc of the slot is schematically illustrated by the angle "d." (See FIG. 7.) In addition, the radially inwardly inclined edge beads 66 and 67 are formed on the edges defining the slot 65 in the inner connector. These edge beads may be of approximately the same arcuate or circumferential length, in cross-section. Thus, the arcuate lengths of beads 66 and 67 are designated as "e" and "f," respectively.
As illustrated in FIG. 6, the upper pin 33 has its lower end 39 inserted within the inner connector member 52 and is secured therein either by a self-tapping thread or by other mechanical means. Similarly, the upper end portion 41 of the lower pin 40 is inserted and fastened within the lower end of the inner connector member 52.
The shutter is mounted within the upper and lower tracks, in the conventional manner, by moving the respective pins and the wheels on the upper pins endwise into the channels. Once the shutter is mounted within the tracks, the shutter may be unfolded to cover the building opening or folded to uncover the building opening. FIG. 4 illustrates a fragment of the shutter showing the slats moved into the unfolded or covering position. FIG. 5 illustrates the shutter folded with the slats comprised against each other for uncovering the opening in the building.
FIG. 8 is an enlarged illustration showing the relationships between the inner and outer connector members when the shutter is folded, that is, when the slats are compressed together. In this condition, the first larger bead 57 of the outer connector member 51 contacts the bent-edge strip portion 53 of the slat body 50. At the same time, the bead 57 on the inner connector member contacts or is closely adjacent to the second bead 60 formed on the outer member. In this arrangement, the slats are closely compacted, as illustrated in FIG. 5.
When the slats are unfolded, they pivot about their respective connectors. In this condition, the pivoting occurs until the inner member bead 66 contacts or is closely adjacent to the outer member first bead 57 while the outer member's second bead 60 engages the opposite face of the bent-edge strip 53, as illustrated in FIG. 9. With this arrangement, a relatively large angle is formed between the adjacent slats. By way of example, the angle can be approximately 90 degrees which is normally larger than that obtained with conventional accordion-type fold shutters. For example, in the shutter disclosed in the prior U.S. Pat. No. 5,097,883, the angle between adjacent slats is disclosed as being approximately 60 degrees when the shutter system is fully deployed (see col. 6, lines 28-29).
The wider angle of opening the slats, relative to each other, permits the use of narrower slats to cover the same lineal distance that conventional, normally wider slats, cover. Thus, there are more connectors along any particular lineal coverage than might otherwise be utilized in conventional accordion-type shutters. The vertically arranged connectors provide reinforcing bars or columns which resist penetration of the shutter and, more significantly, resist separation of adjacent slats under applied impacts. In conventional shutter connections, there is a tendency for the slats to separate at their connections when subjected to a substantial force resulting from the impact of a wind-hurled object or a manually applied object. The present construction substantially increases the strength of resistance to penetration and separation at the connections between the slats.
FIGS. 10-12 schematically illustrate the effects of applied forces upon the slat connections. FIG. 10 is an enlarged view of two slat connections illustrated in the shutter unfolded position in which the shutter covers a building opening. A large force, schematically illustrated by the arrow 70, is applied against one of the connections. The force may be due to a wind-hurled object, such as building debris or the like, or by a manually applied object, such as a hammer intended to force open the shutter. The force is transmitted through the adjacent slats which would appear in a force vector diagram to act like the legs of an equilateral triangle.
In FIG. 11, the force is sufficient to cause the exposed or impacted portion of the outer connector member 51 to bend or crush radially inwardly. The bead 67 on the inner member resists the inward bending of the outer member. But, as the outer member bends or crushes, it applies pressure to the portion of the inner member, which it overlays. Thus, the inner member bends under the pressure of the bending or crushing portion of the outer member. Simultaneously, one of the slats bends along its narrow edge strip 53, due to the pressure of the bead 60 against that strip. The adjacent slat body, which is in a plane that was Initially tangent to its outer member, bends to partially absorb the force.
As the force continues, or if a heavier force is applied, as shown in FIG. 12, the crushing or inwardly folding movement of the outer member engages and crushes or bends the inner member. Simultaneously, the two slat body portions bend even further to substantially flatten the triangular, in cross-section, shape of the connection between the slats. But, the engagement between the first bead 57 of the outer member and the bead 66 of the inner member becomes tighter even though the bead 57 may be bent slightly out of position. The tight engagement between the two beads 57 and 66 locks the inner and outer connector members together to prevent their separation due to the impact force.
Depending upon the intensity of the applied forces, the inner and outer connector members may bend, more or less. Likewise, the impact forces may cause greater or lesser flattening of the otherwise triangular configuration of the slats.
While the sizes and shapes of the parts forming the slat body portions and their respective connector members may vary, a practical or commercial set of dimensions, for illustration purposes, are as follows: with the slats extruded out of a conventional, aluminum material used for this type of product, the thicknesses of each slat may be on the order of about 0.1 inches and the widths approximately 4.0 inches to about 4.2 inches. The outer connector member may have a diameter of approximately 0,536 O.D. and 0.436 I.D. The arc "a" of the slot is approximately 99 degrees, with the arc small "b" of the first bead 57 is approximately 36 degrees and the arc small "c" of the second bead 60 approximately 26 degrees. The inner member may be approximately 0.320 O.D. and 0.22 I.D. with its slot are "d" approximately 49 degrees and its bead arcs small "e" and small "f" about 22 degrees. The obtuse angle formed by the bent-edge strip 53 with its body member 50 is approximately 120 degrees.
The foregoing dimensions and angles are not critical but rather are approximate to illustrate the relationships of the components forming the pivotal connections and the relative proportions of the slats.
The overall construction of the shutter appears, to the observer, to be conventional in all respects. Thus, although the shutter does not appear to be different, nevertheless, it is able to withstand substantially greater impact forces than conventional shutters without any change in its acceptable aesthetic appearance. In addition, the construction permits the use of relatively thin, aluminum or plastic extrusions to provide the desired protection, that is, to avoid the necessity of substantially greater thickness and size slats which otherwise would substantially the expense of constructions.
This invention may be further developed within the scope of the following claims. Therefore, the foregoing description should be read as being merely illustrative of an operative embodiment and not in a strictly limiting sense. | The opposite, vertically elongated edges of a series of pivotly connected slats forming an accordion-type folding shutter are provided with integral tube-like connector members. One of the connector members is of a smaller diameter than the other to form an inner member which co-axially fits within the next adjacent outer member of the next slat. The inner members are connected to their respective slat edges by a narrow strip, extending the full length of their respective slats and arranged at an obtuse angle to the remainder of their slats, with the narrow members fitting through a slot in the adjacent outer member. The strip pivots within the slot of its outer member and engages beads integrally formed on the edges defining the slot in the outer member. The inner member is formed with a pair of radially outwardly extending beads, one of which engages one of the beads on the outer member when the slats are pivoted into their shutter extended position, thereby spacing the outer surface of the inner member from the inner surface of its outer member. The slat integrally joins its outer member along a plane which is tangent to the outer surface of the outer member, so that the extended adjacent pair of slats form a roughly 90 degree angle triangle when the shutter is extended. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention is a continuation of, and claims priority from, U.S. patent application Ser. No. 10/845,786, filed May 12, 2004, by the present inventor, and entitled “Armored Stripper Rubber”.
FIELD OF THE INVENTION
[0002] This invention relates to a long-lasting, deformation-resistant, rubber or elastomer-based seal having a configuration for dynamically sealing against tubular members or drillstring components movable longitudinally through the seal. In particular, the invention relates to stripper rubbers, inserts, and insert assemblies, for stripper rubbers used with rotating control heads, rotating blowout preventers, diverter/preventers and the like, in oil, gas, coal-bed methane, water or geothermal wells.
BACKGROUND OF THE INVENTION
[0003] In the drilling industry, seals are used in various applications including rotating blowout preventers, swab cups, pipe and Kelly wipers, sucker rod guides, tubing protectors, stuffing box rubbers, stripper rubbers for coiled tubing applications, snubbing stripper rubbers, and stripper rubbers for rotating control heads or diverter/preventers. Stripper rubbers, for example, are utilized in rotating control heads to seal around the rough and irregular outside diameter of a drillstring of a drilling rig.
[0004] Stripper rubbers are currently made so that the inside diameter of the stripper rubber is considerably smaller (usually about one inch) than the smallest outside diameter of any component of a drillstring. As the components move longitudinally through the interior of the stripper rubber, a seal is continuously affected.
[0005] Stripper rubbers affect self-actuating fluid-tight seals in that, as pressure builds in the annulus of a well, and in the bowl of the rotating control head, the vector forces of that pressure bear against the outside surface or profile of the stripper rubber and compress the stripper rubber against the outside surface of the drillstring. The pressure forces complement the stretch-fit forces already present in the stripper rubber. The result is an active mechanical seal the increases the seal strength as the well bore pressure increases.
[0006] Well pressure forces often distort the elastic profile of a stripper rubber, deforming the shape from that of a cone to that of a donut. Lowering an oil tool through the stripper rubber often causes the deformed, rolled up, rubber to temporarily uncurl, but the rubber quickly returns to the deformed donut shape once it is re-pressurized. Wear and tear on the stripper rubber occurs, therefore, not only from frictional forces between the rubber and a longitudinally moving oil tool, but from the mechanical forces acting on the rubber as it rolls up and unrolls during drilling operations.
[0007] Stripper rubbers seal around rough and irregular surfaces of varying diameters such as those found around a drill pipe, tool joints, or a Kelly, and are operated under drilling conditions where strength and resistance to wear are prized attributes. When using a stripper rubber in a rotating control head, the longitudinal location of the rotating control head is fixed due to the mounting of a stripper rubber onto a bearing assembly. The bearing assembly allows the stripper rubber, or stripper rubbers, to rotate with the Kelly or drillstring, but restrains the stripper rubber from longitudinal, axial, movement. Wear of the interior surface of a stripper rubber is caused by relative longitudinal movement of the drillstring components, including the end to end coupling areas of larger diameter joints and the larger diameter of tools that bear against a stripper rubber.
[0008] Wear and tear upon a stripper rubber from frictional and mechanical forces will, over a period of time, cause a thinning or weakening of the elastic material to the point that the stripper rubber will fail. Such wear is exacerbated by the movement of multiple lengths of a drillstring through the stripper rubber, such as when a drillstring is “tripped” into or out of the well. Furthermore, the stretch-fit of the rubber rapidly becomes exhausted, and the rubber fails to seal the well. Rapid exhaustion of the rubber remains a persistent problem, and requires frequent, sometimes as often as weekly, replacement of the stripper rubber.
[0009] Metal structures, called “inserts,” embedded in the rubber portion of a stripper rubber are used to provide connectors and structural support to the rubber. For example, U.S. Pat. No. 5,647,444, issued to the present inventor, discloses a dual stripper rubber apparatus. Each stripper rubber provides a pair of circular spring inserts that circumnavigate the packer perpendicular to the drillstring bore. The springs provide structural support to the rubber, yet permit the rubber to dilate so that pipe joints or tools can pass through the drillstring bore of the stripper rubbers.
[0010] Wear is present in all drilling and production applications where a rubber seal or wiper is subjected to the relative movement of a component such as a drillstring tool. A long-felt need persists for a rubber seal or wiper that is resistant to wear, will withstand the great bore hole pressures of modern wells, and is capable of a longer service life than has been heretofore possible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention is further described in the detailed description that follows, by reference to the noted drawings by way of non-limiting examples of embodiments of the present invention, in which like reference numerals represent similar parts throughout several views of the drawings, and in which:
[0012] FIG. 1A is an isometric-view schematic drawing of an insert assembly of one embodiment of the present invention in a contracted posture.
[0013] FIG. 1B is an isometric-view schematic drawing of the insert assembly of FIG. 1A in a dilated posture.
[0014] FIG. 2A is a side view of an insert assembly of FIG. 1A .
[0015] FIG. 2B is a side-view vertical cross-section of the insert assembly of FIG. 2A through line 1 - 1 .
[0016] FIG. 3 is an isometric-view schematic drawing of a support ring with a single unit of insert armor (finger) pendant therefrom.
[0017] FIG. 4 is a side-view schematic drawing of the support ring-finger assembly of FIG. 3 .
[0018] FIG. 5 is an isometric-view schematic drawing of a support ring of one embodiment of the present invention.
[0019] FIG. 6 is an isometric-view schematic drawing of a finger insert of one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In view of the foregoing, the present invention, through one or more of its various aspects, embodiments and/or specific features or sub-components, is thus intended to bring out one or more of the advantages that will be evident from the description. The present invention is described with frequent reference to stripper rubber inserts. It is understood that a stripper rubber insert is merely an example of a specific embodiment of the present invention, which is directed generically to resilient substrate inserts within the scope of the invention. The terminology, therefore, is not intended to limit the scope of the invention.
[0021] Long lasting stripper rubbers have been a long felt need in the drilling industry. The advantage of a longer lasting stripper rubber is not only one of safety, but also one of expense since a longer lasting stripper rubber will reduce the number of occasions when the stripper rubber must be replaced, an expensive and time consuming undertaking. A further consideration is the tremendous borehole pressures encountered in modern drilling. Technology enables under balanced drilling. A challenge of modern drilling is to control the great and variable pressures of high-pressure reserves.
[0022] The present invention provides stripper rubbers, inserts, and stripper rubber-insert assemblies that substantially preserve the profile of the rubber under pressure. An advantage of preserving the rubber profile under pressure is that deformation of the rubber caused by the bore pressure of the well is significantly inhibited from blocking the passage of a tool or drillstring joint through the drillstring bore of the stripper rubber.
[0023] Another advantage of the present invention is that tools or drillstring joints are tripped up or down hole while the stripper rubber maintains a fluid-tight seal around the drillstring under the pressures of modern wells. The present invention permits the stripper rubber to dilate so that drillstring and tool joints can be tripped through the bore, and then contract around smaller diameter drilling tube with a fluid-tight seal.
[0024] Generally, stripper rubbers have a frusto-conical shape, being internally wider at the top than at the bottom. The interior shape facilitates passing a joint or tool downhole through the drillstring bore of the stripper rubber by providing a wide top opening to accommodate the tool joint, and tapering downward to a narrower interior opening at the bottom so that the rubber maintains a fluid-tight seal around the drillstring as the tool joint passes through. The resilient nature of the rubber permits the tapered portion of the stripper rubber to dilate so that the tool can pass through.
[0025] In the absence of external pressure, an annular void exists between the exterior surface of the drillstring and interior surface of the tapered rubber, approximately where the tapering begins at the top of the rubber and extending downward to where the rubber seals around the drillstring. The void exists because the exterior surface of the drillstring has a substantially uniform outer diameter whereas the interior surface of the stripper rubber tapers downward from wider to narrower. The tapered interior shape of the striper rubber facilitates “stabbing” a tool joint through the drillstring bore of the stripper rubber, where the diameter of the tool joint is wider than the lower (narrow) portion of the interior of the stripper rubber drillstring bore.
[0026] In operation, upward and inward bore pressures from the well deform typical stripper rubbers and push rubber into the void, filling the void with pressurized rubber. It becomes difficult, therefore, to trip drillstring joints or tools through the stripper rubber. The advantages of the tapered shape of the stripper rubber are lost when the rubber is under pressure.
[0027] The present invention provides an armored stripper rubber with pivoting inserts that form a dynamic, dilatable and contractible external shell around the rubber. The shell is somewhat analogous to the shell of an armadillo or pill bug. The inserts act in concert to substantially maintain the profile of the rubber under pressure to significantly inhibit pressurized rubber from infiltrating into the void. An advantage of the present invention, therefore, is that tool or drillstring joints may pass through the stripper rubber without encountering a blockage of pressurized rubber filling the void. A further advantage of the present invention is that it increases the capability of the stripper rubber to provide an effective seal around the drillstring and drillstring components. That is, an effective seal is maintained at pressures that would cause prior art stripper rubbers to fail.
[0028] Referring to the drawings, FIG. 1A is an isometric-view schematic drawing of an insert assembly of one embodiment of the present invention in a contracted posture. Assembly 100 is depicted without the elastic sealing material, or other resilient substrate, in which the various inserts are at least partially embedded, in order to view the “cage” formed by the assembly of inserts provided by the present invention.
[0029] In broad strokes, assembly 100 includes support ring 500 and a plurality of insert “fingers” 600 pendant therefrom. Fingers 600 taper downward from support ring 500 and fit together to form a frusto-conical exterior shape. To provide dynamic resiliency, fingers 600 pivot from support ring 500 such that the narrow, bottom, portion of assembly 100 can dilate and contract, depending on the external diameter of the structure (not shown) disposed or passing through assembly 100 .
[0030] It is evident from the drawing that shell formed by the inserts in the contracted posture substantially prevents a stripper rubber from contracting to an internal bore diameter smaller than a pre-selected diameter, because the “plates” of the shell fit together and effectively stop further contraction, even under high pressure. Accordingly, the present invention effectively inhibits infiltration, such as puckering or inversion of the resilient substrate, into the drillstring bore of the stripper rubber, which typically occurs with prior art rubbers when they are exposed to downhole well pressures.
[0031] FIG. 1B is an isometric-view schematic drawing of insert assembly 100 of FIG. 1A in a dilated posture. Insert fingers, or plates, 600 resiliently and elastically pivot radially inward and outward from supprt ring 500 to facilitate the passage of drillstring components through the drillstring bore of the stripper rubber while maintaining an effective fluid-tight seal around the drillstring.
[0032] Stripper rubbers having a connector insert that provides means for connecting the stripper rubber to an adapter, inner barrel, or other piece of drilling head equipment, are known in the art. To attach a stripper rubber of the present invention to an inner barrel or other piece of drilling head equipment, therefore, support ring 500 is connected to a connector insert (not shown). For example, support ring 500 may be spot welded, bolted, formed with, or otherwise adapted to a connector insert.
[0033] In alternative embodiments, however, support ring 500 , indeed, assembly 100 , is not attached directly to a connector insert, and relies, instead, on the mechanical bonding forces of the cured rubber (or other resilient substrate) of the stripper rubber to maintain an attachment to a connector insert.
[0034] FIG. 2A is a side-view of an insert assembly of FIG. 1A . FIG. 2B is a side view vertical cross-section of the insert assembly of FIG. 2A through line 1 - 1 . In the absence of well pressure, void 200 exists between exterior surface 210 of the drillstring, indicated by a vertical dashed line, and interior surface 220 of the stripper rubber. Annular seal point 230 , where tapered interior surface 220 of the stripper rubber contacts drillstring surface 210 , defines the lower perimeter of void 200 .
[0035] Although the rubber substrate of a stripper rubber is resilient or elastic to a certain extent, the substrate is, nevertheless, a cured polymer that generally requires substantial force to elastically deform. Under the well pressures of typical wells, and certainly under the high pressures of particular wells, the rubber substrate of a typical prior art stripper rubber would be forced upward, deforming the profile of the rubber such that the rubber at least partially fills void 200 . Catastrophic deformation is known to occur, where the stripper rubber deforms into void 200 to such an extreme, or with such force, as to “blowout” the rubber. “Blowout” is a misnomer, in that the rubber actually implodes inward, perforates, and pressurized fluids burst upward to blast out into the atmosphere.
[0036] The present invention, however, substantially overcomes the problem of blowouts. In the embodiment of FIG. 2 , for example, finger inserts 600 provide structural support to the rubber substrate of the stripper rubber to substantially preserve its profile and inhibit the infiltration of void 200 by pressurized rubber. The insert cage around the exterior of the rubber and the drillstring through the stripper rubber drillstring bore, combine to confine the rubber such that, effectively, the rubber becomes less elastic. One advantage of the loss of elasticity is that the fluid-tight seal can be maintained at high pressures. Another advantage of the loss of elasticity is that blowouts are substantially reduced.
[0037] Exterior surface 610 of each finger 600 extends outward at least slightly beyond flush with exterior surface 240 of the rubber portion of the stripper rubber. When in a contracted posture, such as when pressurized, finger inserts 600 substantially encase the rubber substrate in a shell of rigid material, such as metal, which withstands the well pressure without substantial deformation. Accordingly, joints can be tripped through the stripper rubber without encountering a significant blockage of confined pressurized rubber.
[0038] Since fingers 600 are pivotally suspended from ring 500 , an additional benefit of the present invention is that the stripper rubber of the present invention is able to dilate, while maintaining a fluid-tight seal, to allow joints to trip through without compromising the seal, and then to contract around the drillingstring to preserve the fluid-tight seal after the joint has passed. Alternative embodiments further provide one or more circumferential spring inserts (not shown) axially positioned in the substrate to provide additional structural support or to reinforce the fluid-tight seal.
[0039] Support ring 500 is entirely embedded in the rubber substrate. The attachment of fingers 600 to support ring 500 , therefore, is reinforced by the rubber.
[0040] FIG. 3 is an isometric-view schematic drawing of support ring 500 with a single unit, or “finger,” of insert armor 600 pivotally pendant therefrom. Ring 500 defines drillstring bore 300 , through which lengths of drillstring, together with attendant joints or tools, are tripped up or down well.
[0041] Support ring groove 510 traverses the circumference of ring 500 perpendicular to drillstring bore 300 . Insert finger 600 is oriented such that surface 610 is an exterior surface and surface 620 is a side surface. The side opposite surface 610 , i.e., the interior surface of finger 600 , provides insert flange 630 , which extends inward toward bore 300 . Hinge portion 640 and groove 510 are cooperatively adapted to provide a pivoting attachment. Particular embodiments of the invention allow for insert finger 600 to “snap” on to support ring 500 at groove 510 to accomplish the pivoting attachment. Other embodiments (not shown) provide a pin and bore type hinge.
[0042] FIG. 4 is a side-view schematic drawing of the support ring-finger assembly of FIG. 3 . Hinge portion 640 of insert 600 provides a convex extension, or lip, 650 (male) that mates with concave groove 510 (female) of support ring 500 . Alternative embodiments (not shown) of the invention provide an inverse relationship, wherein support ring 500 has a male, or convex, circumference 510 , and hinge portion 640 has a female, or concave portion 650 , that mate together to form a pivoting attachment.
[0043] Insert flange 630 is recommended to provide one or more flange bores 660 . Bores, or perforations, 660 become infiltrated with fluid rubber, or other suitable elastomeric material, during manufacture of the stripper rubber. Once the rubber is cured, bores 660 enhance the physical, mechanical, bond of insert 600 to the rubber substrate.
[0044] FIG. 5 is an isometric-view schematic drawing of support ring 500 of one embodiment of the present invention. The inner diameter of drillstring bore 300 should be sized to accommodate the largest joint or tool to be tripped through the stripper rubber. Accordingly, the present invention contemplates embodiments of varying diameters as defined by the diameter of bore 300 .
[0045] Support ring 500 is an insert that is entirely embedded in the rubber substrate of the stripper rubber. It is recommended that the exterior surface of ring 500 be as devoid as practicable of sharp edges or acute angles so as to minimize the ability of the ring to cut or shred the rubber as the result of shearing actions from elastic deformation. Chamfer 520 , for example, bevels an interior circumferential edge of ring 500 to reduce the sharpness of the edge.
[0046] FIG. 6 is an isometric-view schematic drawing of finger armor insert 600 of one embodiment of the present invention. The view features the interior side of insert 600 . Inserts are typically made of metal or metal alloys, but the present invention further contemplates that inserts may be synthetic, composite or any suitably durable material. Forming a strong bond between the insert and the rubber substrate is an engineering challenge recognized in the art. One strategy is to provide perforated inserts.
[0047] During production of the present invention, for example, fluid elastic material such as rubber, or any suitably resilient substrate, fills flange bores 660 so that, upon resilient hardening or curing of the substrate, finger 600 becomes mechanically embedded, except for exterior surface 610 , in the material and thus becomes an insert. In effect, flange 630 is gripped by the cured rubber through perforations 660 so that it is very difficult for insert 600 to slip out of the rubber. Beveled edges for perforations 660 reduce shear that would tend to cut the rubber.
[0048] While recommended, perforations 660 are not required. The particular number, shape, size, orientation, or other parameters of the perforations may be selected as desired or as recommended by experience. Alternative embodiments of the present invention, for example, provide perforations (not shown) through recesses 670 which extend out through exterior surface 610 . Particular embodiments of such perforations through recesses 670 provide a relatively small diameter bore proximate to recesses 670 opening to a relatively larger diameter bore proximate to surface 610 . Other means for enhancing the mechanical grip of the rubber on the insert include dimples (concave recesses), bumps (convex extensions), or any topological feature, or combinations thereof, that the rubber can grip.
[0049] To further enhance the strength of the insertion, one or more recesses 670 are filled with a bonding agent that provides, or improves, the chemical bond between the insert and the cured rubber. The combination of chemical bonding with mechanical gripping provides a highly reliable stripper rubber insert assembly.
[0050] Each finger insert 600 tapers downward at an angle compatible with the tapering of the stripper rubber. Side surface 620 , on each longitudinal side of insert 600 , is angled inward. When the insert “cage” of the depicted embodiment is assembled, with a plurality of finger inserts 600 pivotally suspended from a support ring, and the assembly is in a contracted posture, the inward angle of each side surface 620 is adapted so that fingers 600 substantially fit together to provide a shell of armor around the rubber substrate. See FIG. 1 . In an embodiment having 12 finger inserts forming the cage, for example, each side surface 620 angles inward at 30°. The inward angle is adapted to provide a selected fit of the fingers, depending on the number of fingers provided in a selected embodiment of the invention. A significant feature of the cage of the present invention is that the cage stops further significant contraction of the stripper rubber once the plurality of fingers 600 are compressed together.
[0051] Operationally, a stripper rubber contracts under the pressure of a well. In fact, it is not uncommon for the rubber to invert or pucker under high pressure, thus compromising the seal and/or causing drillstring pipe to become stuck within the rubber. Inadequate structural support to stop the contraction and maintain the rubber profile is a prime contributing factor to such problems.
[0052] An advantage of the present invention is that, by virtue of fitting together to form a shell when the stripper rubber is exposed to operational well pressures, finger inserts 600 physically contact each other along sides 620 and stop the shell from contracting any smaller than a specific diameter. The shell substantially prevents inversion or puckering of the rubber and, thus, substantially reduces incidents of undesirable results from rubber deformation.
[0053] Particular embodiments of the present invention provide finger inserts 600 that extend substantially the entire longitudinal length of the stripper. Other embodiments provide inserts 600 that are some selected length shorter than the stripper rubber, so that a desired length of rubber extends beyond the bottom of the shell. A specific embodiment may be selected depending on the nature of the performance that is desired by the well operator. A longer insert provides greater structural support to reduce rubber deformation, whereas a shorter insert may provide a better fluid-tight seal.
[0054] The finger insert embodiment depicted in FIG. 6 is formed to provide a finger shoulder 680 proximate to, and to either side of, hinge portion 640 . Alternative embodiments substantially eliminate finger shoulders 680 , so that hinge sides 690 are substantially contiguous with insert sides 620 .
[0055] Further advantages of the present invention include a stripper rubber that maintains its profile, that is, resists longitudinal elastic deformation from bore pressures acting on the resilient substrate. Another advantage of the present invention is a stripper rubber that withstands the high, sometimes explosive, bore hole pressures encountered in certain wells. By providing a stripper rubber that withstands high pressure, the present invention enables effective pressure control for high pressure wells.
[0056] Although the invention has been described with reference to several exemplary embodiments, it is understood 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 invention in all its aspects. Although the invention has been described with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed; rather, the invention extends to all functionally equivalent technologies, structures, methods and uses, either now known or which become known, such as are within the scope of the appended claims. | A stripper rubber comprising a resilient stripper rubber body, an insert support, and a plurality of stripper rubber inserts. The resilient stripper rubber body has a drillstring bore extending therethrough. The insert support is at least partially within the body. The insert support includes a central opening generally aligned with the drillstring bore thereby allowing a drillstring to pass jointly through the central opening and the drillstring bore. The plurality of stripper rubber inserts are each at least partially disposed within the body. The inserts are arranged in a side-by-side manner around the drillstring bore with a first end portion thereof pivotably engaged with the insert support. Each one of the inserts is offset from the drillstring bore for precluding the inserts from being exposed from within the body at the drillstring bore. | 4 |
FIELD OF THE INVENTION
This invention relates to refiners in general and to rotary refiners in particular.
BACKGROUND OF THE INVENTION
Disc refiners are utilized in papermaking to prepare wood fibers to be made into paper on a papermaking machine. Disc refiners are generally divided into two types: those for refining high consistency stocks containing 18 to 60 percent fiber by weight; and those for refining low consistency stocks having two to five percent fiber by weight. High consistency refiners produce mechanical and semi-mechanical pulp or furnish from undigested wood chips and semi-digested wood chips. These refiners break down the wood chips and clumps of wood fibers into individual fibers from which paper is formed.
Processing of fibers in a low consistency refiner may be performed on both chemically and mechanically refined pulps, and in particular may be used sequentially with a high consistency refiner to further process the fibers after they have been separated in the high consistency disk refiner. In operation, a low consistency disc refiner is generally considered to exert a type of abrasive action upon individual fibers in the pulp mass so that the outermost layers of the individual cigar-shaped fibers are frayed. This fraying of the fibers, which is considered to increase the freeness of the fibers, facilitates the bonding of the fibers when they are made into paper.
Paper fibers are relatively slender, tube-like structural components made up of a number of concentric layers. Each of these layers (called "lamellae") consists of finer structural components (called "fibrils") which are helically wound and bound to one another to form the cylindrical lamellae. The lamellae are in turn bound to each other, thus forming a composite which has distinct bending and torsional rigidity characteristics. A relatively hard outer sheath (called the "primary wall") encases the lamellae. The primary wall is often partially removed during the pulping process. The raw fibers are relatively stiff and have relatively low surface area when the primary wall is intact, and thus exhibit poor bond formation and limited strength in the paper formed with raw fibers.
It is generally accepted that it is the purpose of a pulp stock refiner to partially remove the primary wall and break the bonds between the fibrils of the outer layers to yield a frayed surface, thereby increasing the surface area of the fiber multi-fold.
Disc refiners typically consist of a pattern of raised bars interspaced with grooves. Paper fibers contained in a water stock are caused to flow between opposed refiner discs which are rotating with respect to each other. As the stock flows radially outwardly across the refiner plates, the fibers are forced to flow over the bars. The fiber treating action is thought to take place there, between the closely spaced bars on opposed discs. It is known that sharp bar edges promote fiber stapling and fibrillation due to fiber-to-fiber action. To achieve this, an advantageous method of fabricating bars which wear sharp has been utilized in the construction of refiner plates such as disclosed in U.S. Pat. No. 5,165,592 to Wasikowski. It is also known that dull bar edges result in fiber cutting by fiber-to-bar action. Fiber cutting is undesirable because it results in paper of weaker strength and renders a certain portion of the fibers too small to be retained on the screen on which the paper is formed, thus increasing waste.
The preferred action in refining paper fibers is fibrillation. Fibrillation is the breaking down of the primary wall and partially releasing the fibrils of the outer layer to yield the frayed surface, which increases the surface area of the fiber multi-fold. Improved fibrillation with minimal fiber damage has been theorized as possible if a refiner bar having a rough or abrasion resistant edge is used. The rough or abrasion resistant edge, which resists dulling during operation, holds the fibers longer while the sharpness of the rough surface acts to gently abrade the fibers. A rough or abrasion resistant edge is difficult to obtain without affecting all of the surrounding surfaces. If all of the surrounding surfaces are treated, fiber flow through the refiner may be impaired by the loss of open area in the grooves between the refiner bars as well as by the added friction of the abrasive material. Treatment of the entire groove and treatment of the bar surface have been accomplished by surface modification techniques but the edge has not been isolated.
Both theory and logic suggests that work is being done to wood fibers passing through a refiner principally as the fibers pass over the outermost surface of the bars. Thus, it is desirable to retain the fibers on the outermost surface and to build up a fiber pad thereon to promote refining. One way to retain fibers on the outermost surface of refiner bars is to make the surface rough. The roughness creates numerous edges to hold the fibers so that they may be refined.
There are many ways of depositing a rough surface or other coating on a refining plate bar, but these have all involved adding thin layers of material on top of the bars after they have been finished because the bar surfaces must be ground to obtain flatness and bar depth requirements. Thus, the problem associated with depositing a rough surface or other coating on the outermost surface of the refiner bars is that, on the one hand, it can affect the flatness of the bars, which interferes with the ability to run opposed discs closely spaced; and on the other hand, there is a tendency of the relatively thinly deposited layer to rapidly wear away during operation in a refiner.
What are needed are techniques for creating localized areas of surface roughness which resist wearing away.
SUMMARY OF THE INVENTION
The disk refiner of this invention employs refiner bars integrally formed with the refiner plate which have selected regions of high roughness, resistance to abrasion or other unique characteristics. In one of the embodiments of the invention, an abrasive or other material is deposited or formed in U-shaped, V-shaped, or trapezoidal grooves which are formed down the center of the uppermost surface of the refiner bars. Roughness centrally located in the bars serves to retain wood fibers on the uppermost surface of the bar where the refining action is thought to take place. In this way the fibers are retained for an extended period of time in the location where the most refining action is taking place, thus increasing the fibrillation of the fibers which increases the strength of the papers made from the fibers.
Another embodiment places abrasive or other materials on one or both sides of the blade so that the leading edge or trailing edge of the refiner bar is constructed of abrasive materials. Yet another way of achieving an abrasive surface over the entire upper surface of the bar including the leading and trailing edges is to form the bar of a white iron alloy which may be heat treated to form a soft matrix with embedded carbide grains. The carbide grains may be exposed to form a rough surface either by normal wear of the refiner disc in use or by etching the bar surface with an acid such as concentrated sulfuric or hydrochloric acid. Selective regions of roughness are developed by protecting those portions of the refiner plate and bar on which roughness is not desired, mainly the grooves which are formed by the sides of the bars, with a protective material that prevents erosion or etching such as a paint polymer or an etch- and wear-resistant metal. Thus, a refiner disc is formed of a white iron alloy and the entire refining surface together with the bars are coated with an etch-and wear-resistant surface. Subsequent to coating, the normal procedure for forming the uppermost surface of the bars, that of grinding the bars parallel to the plate, is performed. The grinding operation selectively removes the wear- and etch-resistant coating from the top or the uppermost surface of the bars. The bars may then be etched with acid or allowed to wear naturally to form a rough surface on the entire upper surface of the bars.
It is a feature of the present invention to provide a refiner disc with refiner bars which have unique characteristics in selected locations.
It is another feature of the present invention to provide refiner discs having refiner bars wherein the edges of the bars are rough.
It is a further feature of the present invention to provide refiner bars wherein the central portion of the bar is rough to retain a fiber mat thereon.
Further objects, features, and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side-elevational view, in particular cross-section, of a low consistency disc refiner.
FIG. 2 is a segment of a disc refiner plate of this invention.
FIG. 3 is an isometric view, partially cut away in section, of a single bar of the disc refiner of FIG. 2.
FIG. 4 is a cross-sectional view of the bar of the disc refiner of FIG. 2.
FIG. 5 is a cross-sectional view of an alternative disc refiner bar.
FIG. 6 is a cross-sectional view of another alternative disc refiner bar.
FIG. 7 is a cross-sectional view of a refiner bar with material of a desired characteristic, such as roughness, placed on the outer edges.
FIG. 8 is a cross-sectional view of an alternative embodiment refiner bar.
FIG. 9 is a cross-sectional view of another alternative embodiment refiner bar.
FIG. 10 is a schematic view of the process of coating the edge of the bar of FIG. 7.
FIG. 11 is a cross-sectional, schematic view of the process of FIG. 10.
FIG. 12 is a schematic view showing the refining action of two sharp bars.
FIG. 13 is a schematic view of the refining action of two dull edge bars.
FIG. 14 is a schematic view of the refining action of two rough edge bars.
FIG. 15 is a fragmentary, cross-sectional view of a bar formed of white cast iron.
FIG. 16 is a schematic cross-sectional view of the bar of FIG. 15 with the matrix shown etched away.
FIG. 17 is a schematic cross-sectional view of the bar of FIG. 15.
FIG. 18 is a schematic, cross-sectional view of the bar of FIG. 17 after it has been milled away.
FIG. 19 is an enlarged, fragmentary view of the rough edge of the bar of FIG. 18.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring more particularly to FIGS. 1-19 wherein like numbers refer to similar parts, a segment for a refiner plate 26 is shown in FIG. 2. Similar segments may be used for a refiner plate 27 operated in opposed, spaced relationship to the plate 26 when installed in a refiner 20. The refiner plates 26, 27 have bars 12 and the bars have selected regions 14 which are constructed of a rough or abrasive material 16. The refiner plates are used to refine fibers in the disc refiner 20.
In the description and claims of the present invention, reference to rough or abrasive material will be used for case of description. It should be recognized, however, that the present invention is useful for providing differential properties within a refiner bar, and may be used to provide localized, unique characteristics such as, but not limited to, wear resistance on a ductile bar, areas of differential corrosion or erosion resistance and the like in addition to roughness or abrasiveness.
A disc refiner 20, as shown in FIG. 1 has a housing 29 with a stock inlet 22 through which papermaking stock, normally consisting of two to five percent fiber dryweight dispersed in water, is pumped, typically at a pressure of 20 to 40 psi. Refiner plates 26 are mounted on a rotor 24. Refiner plates 27 are also mounted to a non-moving head 28 and to a sliding head 30. The refiner plates 27 which are mounted to the non-moving head 28 and the sliding head 30 are opposed and closely spaced from the refiner plates 26 on the rotor 24.
The rotor 24 is mounted to a shaft 32. The shaft 32 is mounted so that the rotor 24 may be moved axially along the axis 34 of the shaft. The rotor has passageways 36 which allow a portion of the stock to flow through the rotor 24 and pass between the refiner plates 26, 27 which are opposed between the rotor and the stationary head 28. A portion of the stock also passes between the refiner plates 26 mounted on the rotor and the refiner plates 27 mounted on the sliding head 30. After being refined by the rotor the stock leaves the housing 29 through an outlet 23.
In operation, the gaps between the refiner plates 26 mounted on the rotor 24, and the refiner plates 27 mounted on the non-rotating heads 28 and 30, are typically three to eight thousandths of an inch. The dimensions of the gaps between the refiner plates 26, 27 are controlled by positioning the rotor between the non-moving head 28 and the sliding head 30. Stock is then fed to the refiner 20 and passes between the rotating and non-rotating refiner plates 26, 27 establishing hydrodynamic forces between the rotating and non-rotating refiner plates. The rotor is then released so that it is free to move axially along the axis 34 by means of a slidable shaft 32. The rotor 24 seeks a hydrodynamic equilibrium between the non-rotating head 28 and the sliding head 30. The sliding head 30 is rendered adjustable by a gear mechanism 38 which slides the sliding head 30 towards the stationary head 28. The hydrodynamic forces of the stock moving between the stationary and the rotating refiner plates 26, 27 keeps the rotor centered between the stationary head 28 and the sliding head 30, thus ensuring a uniform, closely spaced gap between the stationary and rotating refiner plates 26, 27.
As shown in FIG. 3, the bars 12 that perform the refining action on the plates 26, 27 have sides 39 which define the upstanding bars 12. The sides 39 extend upwardly of a base member 40 and are integrally formed with the base member 40. Flow passages 42 between the bars 12 are defined by the sides 39 and portions 44 of the base 40 which form the bottoms of the flow passages 42. Stock comprised of wood fibers suspended in water flows between the plates 26, 27 as shown in FIG. 1. The flowing stock principally travels in the flow passages 42. However, as the stock traverses the plates 26, 27, the bars 12, as shown for example in FIG. 2, are designed to cause the stock to pass over the bar tops 46. It is while the wood fibers pass over bar tops that they are engaged by the bars on the opposed disc, and thus refined.
In existing refiner plates, an abrasive material has been sprayed or coated on the upper surface of the bars. However, the discs and bars operating in a refiner are subject to extensive wear over their useful life and the surface coating of abrasive is rapidly worn away. In accordance with the present invention, the base member and bars of the refiner plate are integrally formed of a first material. The bars are shaped to define reservoirs, and a second material, chosen for a specific characteristic such abrasiveness, fills the reservoir. As shown in FIG. 3, in the refiner plates of this invention, the bars 12 have upwardly extending side members 13 which are spaced from one another to define deep reservoirs such as U-shaped grooves 48 which extend downwardly from the bar top upper surface 50 toward the refiner disc base member 40. The manufacture of the refiner plates 26, together with the bars 12, is preferably formed by sand casting. The rough or abrasive material 16 may be of any granular material with high hardness and wear resistance such as, but not limited to, alumina, silica, zirconia, silicon carbide, tungsten carbide, vanadium carbide, and niobium carbide. Materials having other desired properties also may be used. The material may be placed or formed within the groove 48 by a number of techniques.
One technique is set forth in U.S. Pat. No. 5,492,548 which is incorporated herein by reference. The process in the foregoing application involves placing the material in the sand mold used to form the refiner plate 26. In order that the material may become an integral part of the refiner bars 12, it may advantageously be coated with a flux material. The flux material causes the material 16 to be temporarily bonded together and at the same time facilitates the penetration of the granular material by the molten base metal from which the refiner plates 26, 27 are formed. Thus, in the finished product, an abrasive or other material 16 is embedded in a matrix of the material used to form the plates, the plates typically being formed of cast iron, preferably a white cast iron or stainless steel.
Thus the bars 12, as shown in FIGS. 3 and 4, have portions 52 of the bar top surfaces 50 which are rough and further remain rough as the upper surface 50 of the bar wears away.
This rough portion 52 of the upper surface retains wood fibers as they flow over the bar tops 46, thus increasing the time during which the wood fibers may be subject to the refining action of the opposed plates 26, 27 in a refiner as shown in FIG. 1.
The reservoirs filled with abrasive material may be of various groove configurations, as shown in the embodiments of FIGS. 5-9.
FIG. 5 shows an alternative embodiment refiner bar 54 with a V-shaped groove 56 filled with material 58.
FIG. 6 shows a refiner bar 60 with a trapezoidal groove 62 filled with material 64.
The V-shaped groove 56 in the bar 54 and the trapezoidal shaped groove 62 in bar 60 are examples of other groove shapes which may be readily formed in a cast refiner plate.
Fibrillation is the external disruption of the lateral bonds between surface layers of a fiber that results in partial detachment of fibers or small pieces of the outer layers of the fibers and internal or lateral bonds between the adjacent layers within the fibers. Fibrillation occurs during the mechanical refining of pulp slurries. In a disc refiner, a substantial portion of the fibrillation is thought to occur between the edges of opposed refiner plates. Paper fibers 74 undergoing refining are shown in FIG. 12. An upper bar 66 has a sharp edge 70, and a lower bar 68 has a sharp edge 72. The fibers 74 are held by the sharp edges 70, 72, and an abraiding or bruising action between the fibers takes place as the bar edges pass over each other as indicated by arrows.
FIG. 13, on the other hand, illustrates how refiner bars 76 and 78, with dull edges 80, 82, tear paper fibers 84. Although it is desirable to increase the surface area of the individual fibers by the process of fibrillation so that the fibers may bond better with each other, it is not desirable to completely break the fibers. Greater surface area between paper fibers results in greater adhesion between fibers which results in stronger paper. On the other hand, shorter paper fibers means less total surface area per fiber. Shortened fibers bond with fewer other fibers than do long fibers, and the paper formed from the shortened fibers is of reduced strength. In addition, fiber fragments that are rendered too small are not retained on the forming wire of a papermaking machine and are thus lost as sludge. The dull edged refiner bars 76, 78 result in a loss of fiber and an increased cost of manufacturing paper from a given fiber stock, along with the additional detriment of producing a weaker paper.
The refining mechanism of sharp edge bars 70, 72 is not completely understood, but it is thought that the sharp edges staple or hold the fibers in place as the refining action takes place.
In practice it has been found difficult to maintain truly sharp edges as the refiner bars 66, 68 are subject to wear in actual use. A number of techniques for causing the bars to wear sharp have been developed.
FIG. 14 illustrates an alternative approach to holding fibers 94 by the employment of rough edges 90, 92 on bars 86, 88. Thus the provision of rough edges on refiner bars can facilitate the fibrillation of wood pulp fibers. In addition, rough edged bars which require a less distinctly sharp edge may be more readily obtained.
FIG. 7 shows a refiner bar 96 in cross-section. The rectangular bar 96 has an upwardly extending central member 101. Small rectangular, corner wedges 98 are formed of an abrasive or other material 99 deposited in edge channel reservoirs extending between the central member 101 and the sides of the bar 96. FIG. 7 shows how once an abrasive material 99 has been emplaced, the upper surface 100 may be ground down to form a leveled surface as required by the close positioning of opposed bars in the refiner plates.
FIGS. 8 and 9 show how the refiner bar 96 may have corner wedges 102 and 104 of varying shapes.
FIGS. 10 and 11 show one method of emplacing the abrasive material by the use of a flame spray gun apparatus 106 which is traversed along the bars 108 of a refiner sector 110 which may be used to make up the refiner plates 26, 28. The gun 106 sprays ceramic materials 112 into rectangular grooves 114 to form corner wedges 98. As shown in FIG. 11, the grooves 114 and the corner wedges 98 in some cases will be placed only on the leading edges 116. As shown in FIG. 14, the edges 90, 92 form leading edges of the bars 86, 88. The refining action takes place at the leading edges, and thus the leading edges are most in need of techniques for making them rough.
The corner wedges 98, 102, and 104 may also be formed by the technique as set forth in U.S. Pat. No. 5,492,540 as was discussed for the formation of the abrasive material 16.
Another approach to forming selected regions of refiner bars of a rough material is to choose a material which tends to wear rough. Table 1 discloses two cast alloys, chromium white iron and nickel chromium white iron (nihard) which when heat treated develop grains of abrasive carbides 120 in a matrix of softer more malleable material 122 as illustrated in FIGS. 15-19. FIG. 15 shows a material after it has been cast and heat treated. FIG. 16 shows the material after it has been exposed to a sulfuric acid etch or has been allowed to wear. As shown in FIG. 16, the softer matrix 122 has worn away to leave exposed grains 124 which form a rough edge 126.
TABLE 1______________________________________MATERIAL C MN SI CR NI MO______________________________________Chromium White 2.4- 0.5-1.0 0.5-2.0 15-30 0.-2.0 0.-4.0Iron 4.0Example: 28% 2.8 0.8 1 28 -- 0.5ChromiumNickel Chromium 2.5- 0.5-1.3 0.5-.8 1.1-11 2.7-7.0 0.-.5White iron 3.7(Nihard)Example: Type 1 3.3 0.6 0.8 2 4.2 --______________________________________
Although the materials listed in Table 1 are not new in the application of the formation of refiner discs 26, 28, the materials' tendency to wear rough has proved disadvantageous because the flow channels between the bars have also worn rough and this impedes the flow of stock through the refiner plates because the flow channels tend to clog with fibers. A solution, as illustrated in FIG. 17, is to coat the side surfaces and top surface with a layer of metal or paint or plastic 132,134 which is resistant to abrasive wear, erosion or corrosion. Thus, the flow channel 128 and the sides 136 of the bars 130 are protected from wearing rough or being etched to form rough surfaces. As shown in FIGS. 17 and 18, the upper surface 138 and edges 140 of the bar 130 may be advantageously exposed by grinding the upper surface of the bar to at one time expose it and render it flat and parallel. A grinding operation to render the bars parallel is a normal part of the overall manufacturing process of a refiner plate.
FIG. 19 shows an enlarged fragmentary view of the edge of the bar 130 of FIG. 18 where it can be seen how the edges of the bar tend to wear rough.
It should be understood that although the improved refiner plates have been described as used with a low consistency refiner, the technique disclosed could be used to form refiner plates for use with high consistency refiners.
It should also be understood that where reservoirs are described as filled with an abrasive, the abrasive could be material of other desired characteristics and could be held in place by a number of techniques, including using an adhesive to bond abrasive grit to the grooves or employing solder to bond the abrasive.
It should be understood that the invention is not limited to the particular construction and arrangement of parts herein illustrated and described, but embraces such modified forms thereof as come within the scope of the following claims. | A refiner plate has bars integrally formed with the refiner plate base member which have discrete regions of selected physical properties. A material possessing the physical property is deposited in a reservoir in the bar, such as a groove. The reservoir may be positioned in the top of the bar and may be of various shapes. Alternatively, the reservoir with material is positioned on the bar leading or trailing edge. Alternatively, an abrasive surface extends over the entire upper surface of the bar including the leading and trailing edges. The bar may be formed of a white iron alloy which is heat-treated to form a soft matrix with embedded carbide grains. By protecting regions of desired smoothness with a wear-resistant protective coating flow is preserved in selected areas. | 3 |
FIELD OF THE INVENTION
This invention relates to the use of vaporized fuel to power an engine and, more particularly, to improvements that enhance fuel efficiency.
BACKGROUND OF INVENTION
It is known that under some conditions the use of vaporized fuel versus liquid fuel for gasoline powered vehicles can reduce the emission of hydrocarbons conveyed into the atmosphere, while also increasing fuel efficiency. The problem that has lingered is how to obtain and retain those benefits over the changing conditions in which such vehicles are typically driven.
SUMMARY OF THE INVENTION
As known and as described in the commonly owned U.S. patent application Ser. No. 10/002,351, (incorporated herein by reference), fuel efficiency can be improved by heating a quantity of gasoline to cause vaporization, directing the vapor into a stream of ambient air, establishing a desired air-to-fuel mixture and directing the mixture into the intake manifold of an engine.
Whereas the system as disclosed in the above application has resulted in significant improvement, it has not achieved the consistency of operation desired.
It is known that there is an optimum fuel-to-air mixture that needs to be maintained. A fuel-to-air mixture of 1 to 20 is likely too rich resulting in an unacceptable percentage of hydrocarbons in the fuel that are not properly combusted and fuel efficiency is reduced. A 1 to 40 mixture is too lean with today's catalytic converters (CATs) and produces an emission of nitrogen oxide that is prohibited by the EPA emission standards. A fuel-to-air mixture of about 1 to 30 is about optimal for current gasoline engines used in vehicles and an objective of the invention is to control the fuel-to-air mixture to maintain the ratio in the range substantially at, e.g., 1 to 30.
Consistent with the above objective, the mixture is monitored and adjusted throughout operation of the engine. This is accomplished automatically by the use of valves that control the flow of vapor fuel and/or ambient air that is mixed prior to entry of the vapor fuel into the engine's intake manifold. The valves are coupled to a control that is in turn coupled to a vehicle's O 2 sensor which senses O 2 emissions in a vehicle's exhaust (a standard feature on most modern vehicles.) It has been learned that the O 2 emissions are directly related to hydrocarbon emissions which as explained is a reflection of the fuel-to-air mixture.
In the preferred embodiment, an electrical output from the O 2 sensor is transmitted to the mentioned control. It is known that the desired reading for the voltage output of the sensor as measured by the control is, e.g., 3 volts. At startup, the reading will typically be at, e.g., 4 volts, indicating a too rich mixture but desirable for startup and warming of the engine. After a time delay to accommodate warm up, any reading above or below, e.g., 3, will activate the control for opening and closing the valve or valves which control ambient air flow and vaporized fuel flow (more accurately an enriched mixture of air and fuel). For example, a 3.2 reading will produce an opening of the ambient air valve and/or a closing of the vaporized fuel flow. A 2.8 reading will produce the reverse.
Whereas it would be presumed and has been assumed that an established fixed setting of fuel-to-air mixture would produce a stabilized mixture throughout the operation of the engine, such has been determined to be not the case. There are many variables that need to be controlled or accommodated. The liquid fuel temperature is known to have the greatest impact on hydrocarbon emissions and fuel efficiency, and that temperature will vary by small but very significant degrees of temperature due to environmental changes, i.e., temperature, elevation, humidity, and the like. Thus, in the preferred embodiment, a quantity of fuel to be vaporized is precisely temperature controlled to substantially eliminate the effect of such environmental variables.
Regardless, there still remain significant changes that are not controlled simply by maintaining the liquid fuel temperature. These remaining variables are accordingly accommodated by monitoring the O 2 sensors. To the extent that the fuel mixture strays from the desired reading from the O 2 monitor, the mixture is corrected, i.e., by changing the setting of a valve or valves.
Whereas the above improvements are considered the primary features for the preferred embodiment, the following is also considered to provide additional benefit.
Again in the preferred embodiment, a quantity of liquid fuel, e.g., one gallon of fuel, is inserted into a vaporization tank. The fuel occupies, e.g., the lower half of the tank, and a heating element and temperature sensor is provided in the fuel-containing portion of the tank. The temperature is set and maintained at, e.g., 74 degrees, and that temperature causes vaporization of the fuel, the vapor rising from the liquid surface into the upper half of the tank. Within the tank, in the upper half, there is an ambient air inlet and a vaporized fuel outlet. A sequence of baffles directs air from the inlet and across the surface of the liquid fuel to the outlet which is connected to an outer first conduit. The ambient air temperature is stabilized by its movement over the liquid and in the process mixes with the rising fuel vapor. As expelled through the outlet and into the first conduit, such becomes the vaporized fuel heretofore alluded to and which is perhaps more correctly identified as an enriched fuel air mixture. A secondary source of ambient air is conducted through a second conduit and merges with the vaporized fuel of the first conduit. Prior to said joining of the air and vaporized fuel, at each or a selected one of the first and second conduits, control valves are provided which control the flow volume from the respective conduits to vary the amount of ambient air and vaporized fuel that is combined into a third conduit or continuing conduit (also referred to as a mixing chamber) which in turn conveys the mixture to the engine's intake manifold.
A further problem for which a solution had to be derived was the discovery that the process as described, when vaporizing the common gasolines that are commercially available, generates a liquid residual that does not readily vaporize, e.g., at the temperature setting considered otherwise optimal. Over a period of time, this liquid residual becomes a greater and greater portion of the liquid content of the vaporization tank. Thus, a provision is made for a periodic purging of the liquid residual from the tank.
Whereas it was determined that the residual liquid burned acceptably well in conventional engines, and particularly to the extent that the systems of the preferred embodiment are adaptable and applied as retrofits to such conventional engines, a first solution is the alternate running of the engine, i.e., on vaporized fuel as described above, and then, as desired, converting back to conventional liquid fuel operation wherein the residual liquid is used to fuel the engine. A recycling procedure may be established to (a) fill the tank with e.g., a gallon of liquid gasoline; (b) vaporizing 80% of the fuel and then switching to conventional engine operation to burn off the liquid residual; and (c) refill the tank and switch back to vaporized fuel. Other solutions are certainly contemplated. The residual can be simply extracted from the tank on a periodic basis, stored until refueling is required, and then disposed of or preferably transferred for use in a conventional engine use. It is theorized that the residual can also be eliminated by periodic higher temperature vaporization which may vaporize the residual at some but acceptable loss of efficiency.
The invention will be more fully appreciated and understood by reference to the following detailed description and drawings referred to therein.
DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic overview of a preferred embodiment of the invention;
FIG. 2 is an operational diagram of the system utilized for the embodiment of FIG. 1 ;
FIG. 3 is an exploded view of the vaporization tank of FIG. 1 ; and
FIG. 4 is a further exploded view illustrating in particular the control valves of the system of FIGS. 1 and 2 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is made to FIG. 1 , which provides a schematic overview of the components of a system in accordance with the present invention. A gasoline-powered engine as labeled, includes an intake port 10 connected to the engine's throttle body. The engine, when operating, draws air and fuel through port 10 . The engine includes an exhaust pipe 12 that is equipped with an O 2 sensor 14 . The engine, intake port 10 and O 2 detector 14 may be standard equipment provided for a conventional gasoline-driven vehicle, and the remainder of the components of the illustrated embodiment are incorporated into the system to achieve the objectives of the present invention.
Item 16 represents an air box through which ambient air is drawn when operating the engine. Air conducting conduits 18 and 20 from air box 16 provide the desired airflow to the remainder of the system as will be described.
Conduit 20 includes a valve 22 that controls the volume of air directed through conduit 20 and which is conveyed to a vapor producing tank 26 via the tank's top or cover 24 .
Conduit 18 includes a valve 28 which controls the volume of ambient air that is directed into a mixing chamber 30 .
Returning to the vapor-producing tank 26 , the tank is provided with flow control apparatus, e.g., baffles, which will be later explained, but for this overview description it will be understood that air from conduit 20 (as controlled by valve 22 ) enters the tank 26 through the top 24 , liquid fuel 28 is drawn from a gas tank 32 via conduit 34 , hot water heating coils immersed in the liquid fuel via inlets and outlets 36 , 38 heat the gas/fuel 28 and generate vapors 40 . The vapors are picked up by the airflow from air conduit 20 and directed out through conduit 42 to the mixing chamber 30 but controlled by valve 44 . The air vapor mixture of conduit 42 is intermixed in mixing chamber 30 with ambient air from conduit 18 , and the mixture is directed through the intake port 10 and from there into the combustion tank of the engine.
Reference is now also directed to FIG. 2 which illustrates an automatic control process for the air, vapor, and fuel flow rates referred to in FIG. 1 . Each valve 22 , 28 and 44 are opened and closed as desired (between any of the unlimited positions between fully opened and fully closed) by motors, e.g., stepper motors 22 ′ 28 ′ and 44 ′.
It has been determined that fuel efficiency can be measured by the hydrocarbons that are emitted from the vehicle exhaust. Unfortunately, the elimination of hydrocarbons from gasoline-produced engines currently available cannot be total as such produces an undesired and unpermitted emission of nitrogen oxides. Thus, one first determines the level of nitrogen oxide that is permitted and then the lowest level of hydrocarbons that will stay within the limits permitted for the restriction on nitrogen oxide.
It has further been determined that O 2 detectors for detecting a level of O 2 in the vehicle's exhaust and which have been incorporated into the exhaust system of later model vehicles, are directly related to the level of hydrocarbons in that same exhaust. Thus, one can determine what O 2 reading of the detector 14 produces the optimum fuel efficiency. For example, a desired hydrocarbon level may be determined to exist when the O 2 monitor produces a reading of 3 volts.
Returning to FIG. 1 , it has been determined that fuel efficiency is achieved by controlling the ratio of fuel-to-air mixture achieved at the mixing chamber 30 from which the mixture enters the engine intake throttle body. It is known that the vapor-air-mixture directed into the mixing chamber 30 from conduit 42 is too rich, e.g., 1 part fuel to 10 parts air, and of course the air only from conduit 18 has zero parts fuel. The desired mixture may be that which achieves a 30 to 1 ratio, e.g., of 2 cubic feet of air, through valve 28 for each cubic foot of air/vapor through valve 44 .
Whereas the valves 28 and 44 can be set to achieve the desired mixture at a given point in time, it has been learned that many factors affect the ratio achieved in the vapor/fuel mixture flowing through conduit 42 .
Assuming a specific hydrocarbon emission is desired, a reading of the O 2 detector will verify that this desired mixture has been achieved, as that reading also indicates the hydrocarbons in the exhaust. As explained, a fixed setting will not likely achieve the optimum ratio over any given period of time. Any temperature change, any elevational change and even differences in fuel make up will skew the vapor/fuel mixture flowing from the tank 26 to the mixing chamber 30 .
Accordingly, the valves 22 , 28 and 44 are operated by stepper motors 22 ′, 28 ′ and 44 ′ (illustrated in the flow chart of FIG. 2 and in exploded perspective view in FIG. 4 ) which stepper motors are automatically operated by computer C. Computer C monitors the O 2 and thus the hydrocarbon emissions in exhaust 12 and should those readings indicate too high or too low hydrocarbons, the stepper motors are activated by the computer to change the relative fluid volumes from conduit 18 and conduit 42 . Should the reading show a too high hydrocarbon level, the vapor/air flow of conduit 44 needs to be lessened, e.g., the valve 44 closed, or, e.g., the valve 28 opened, or, e.g., both closing of valve 44 and opening of valve 28 .
The adjustment may take place in stages, i.e., a 1° closing of valve 44 , a re-reading of the O 2 detector followed by repeated partial closing of valve 44 or alternatively the partial opening of valve 18 or a combination of both. Valve 22 can also be a factor as restricting air flow into conduit 20 will slow the flow of air to the tank 26 , thus to conduit 40 , while also diverting more airflow through valve 28 .
The structure as described enables the designer to design a system that will theoretically provide the desired result in fuel-to-air mixture (e.g., 1 to 30) as deemed desirable, but then in recognition of the impact of small environmental changes that produce substantial deviations in efficiency, provide automatic adjustments that are responsive to real time readouts from an exhaust monitor, e.g., an O 2 detector.
Reference is now made to FIG. 3 , which illustrates the components of the vaporizing tank 26 . The tank 26 consists of a metal box 48 having dimensions of about 4″×8″×12″. Fitted to the bottom of the tank is a hot water coil 50 that includes an inlet 52 and outlet 54 which, when assembled to the box 48 , extends from the box via inlet 52 ′ and outlet 54 ′.
Seated onto the box bottom and over the coil 50 is a baffle grid 56 . The plates of the baffle grid 56 include slots 58 which enable the seating of the grid over the coil 50 . Baffle grid 56 includes fastener tabs 60 and assembled to the fastener tabs 60 is a lower baffle plate 62 having spaced circular opening 64 . The baffle plate 62 is seated below the upper edge of box 48 (defined by flange 84 ) and affixed to the flange 84 is an upper baffle plate 66 . Extending flanges 68 of baffle plate 66 protrude laterally from the box and provide the means to secure the box 48 to the body of the vehicle. Upper flange 68 has rectangular openings 70 .
Secured to the upper baffle plate 66 and in alignment with an air inlet to be described is a secondary upper baffle plate 72 , reduced in size and secured to the upper plate 66 so as to cover a substantial portion of the opening 70 ′. Provided in this secondary plate is a plurality of small holes, e.g., five holes 74 having a size of about a quarter inch in diameter. Baffle plate 72 provides an impediment to airflow from air inlet 78 and diverts the air flow laterally and downwardly within the tank 26 .
Completing the assembly is the top or cover 24 which has a complex shape which can be described as a distorted pyramid shape. The apex of the pyramid shape is positioned at one end whereat an air inlet 78 is provided A vapor air outlet 80 is provided at the same end but along the side wall of the pyramid shape. A flange 82 forming the peripheral edge of the top 24 includes bolt holes which line up with bolt holes in flange portion 76 of baffle plate 66 and with bolt holes in a flange 84 forming the peripheral edge of box 48 . Bolts (not shown) are inserted through the aligned bolt holes to fasten the components together. A float 86 contained in the box 48 determines the level of liquid gasoline contained in the box. The liquid gasoline enters the box through conduit 34 and a recycling conduit 90 is provided to drain and/or circulate the gasoline in the vaporizing tank 26 as may be desired.
In operation liquid gasoline is filled to a level of about ¾ inch in the bottom of the box 48 which is above the position of the heater coils 50 and below the top of the baffle grid 56 . The baffle grid 56 and baffle plate 62 primarily prevent sloshing of the gasoline during driving of the vehicle. As the liquid gasoline vaporizes (induced by the heating coil 50 ) air from inlet 78 is dispersed across the liquid surface via baffle plates 72 and 68 which collects vapors 40 (see FIG. 1 ) and is then directed through outlet 80 and to the mixing chamber 30 via conduit 42 as previously discussed.
As gasoline is vaporized and drawn from the surface of the liquid gasoline, the gasoline level diminishes which is detected by the float 86 . As determined desirable by the system, the gasoline is replenished through inlet 34 . After some period of time, the gasoline starts to become contaminated (does not vaporize) and it is desirable to purge the tank. This can be done by converting the engine to gasoline use and drawing the residual gas of the tank 26 through the conventional gas injection system. It can also be simply drained into a holding tank and utilized for other power equipment, e.g., a powered law mower.
Whereas the above is considered a preferred embodiment, the reader will readily understand that numerous modifications and variations may be made without departing from the intended scope of the invention. Accordingly, the invention is not limited to the structure as described above but fully encompasses the definitions of the appended claims. | A fuel supply assembly is provided that may allow for use of vaporized fuel to power an engine and enhance fuel efficiency. The fuel supply assembly may include a vaporizing tank, a heating source, a temperature control and a monitoring and control system configured to control intermixing of ambient air and vaporized gasoline to maintain a desired hydrocarbon level in an exhaust. | 8 |
PRIORITY CLAIM
[0001] This application is a continuation of pending International Application No. PCT/EP2010/056337 filed on May 10, 2010, which designates the United States and claims priority from German Patent Application No. 10 2009 021 208 filed on May 13, 2011.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a lighting device for streets, pathways and the like. Without admitting to be prior art, such light devices include a housing positioned at a distance from a surface that is to be illuminated. At least one lighting module is mounted on a support in the housing and may include a number of lamp units of equal light distribution characteristics. Each of the lamp units may have multiple light sources and lenses, which may be individually assigned to and positioned in front of these light sources in the direction of the light emission for generating a predefined light distribution pattern. The light device may include different lighting modules which are at least equipped with lamp units displaying a different light distribution characteristic.
[0004] 2. Description of Relevant Art
[0005] EP 1 916 468 A1 describes a lighting device for streets, pathways and the like, with a housing containing multiple lighting modules for generating a predefined light distribution. The housing of the lighting device is mounted on a curbside pole, allowing a longitudinal section of the street to be illuminated as the object surface. The lighting modules mounted in the housing are of an elongated design and are provided with a support on which lamp units of an identical type of light distribution characteristic are installed in rows. Each lamp unit essentially consists of an LED light source and, positioned in front of it in the direction of the light emission, a lens. The lamp units of the lighting module are shielded by a common, transparent cover plate.
[0006] For generating a predefined light distribution of the lighting device, several lighting modules with different types of light sources and/or different light distribution characteristics are employed. A first lighting module includes lamp units with first lenses which in relation to a central plane emit a relatively narrow light cone. A second lighting module includes lamp units with second lenses which in relation to the central axis emit a relatively broad light cone. Third lighting modules include lamp units with third lenses which emit light cones in a dihedral range located between the light cone of the first lamp unit and the second lamp unit. The lighting modules with the lamp units that emit in the dihedral range a relatively narrow light cone are so positioned in the housing that they illuminate a marginal area of the surface to be illuminated. A main area of the surface to be illuminated is illuminated by the lighting modules with the broad-beam lamp units. In relation to the central axis the light cones of the different lighting modules or lamp units are symmetrical. It follows that the lighting device for homogeneously illuminating the street section is relatively complex and expensive. Another drawback is the fact that several differently configured lenses must be used.
SUMMARY OF THE INVENTION
[0007] It is an object of the invention to improve the design of a lighting device in a manner whereby, in simple fashion and as needed, a predefined light distribution is achieved for an homogeneous illumination of an area.
[0008] In an embodiment a lighting device for streets, pathways and the like is provided. The lighting device has a housing that may be positioned at a distance from a surface area to be illuminated. Said housing includes a support board and on the support board at least one lighting module with multiple lamp units of an identical light distribution characteristic, each containing multiple light sources. A lens may be mounted in front of each light source for generating a predefined light distribution, with different lighting modules comprising at least lamp units of a different light distribution characteristic. Lamp units of the same light distribution characteristic have optical axes that extend parallel to each other and at least of one lamp units is configured such that the light distribution characteristic generated by it includes at least one section that is asymmetric relative to a central plane of the lamp unit
[0009] The particular advantage of the lighting device consists in the fact that combining lamp units having an asymmetric light emission characteristic is an effective way to generate a predefined light distribution and especially a relatively homogeneous light distribution. Because the optical axes of the lamp units of identical or different types, meaning lamp units having the same or a different light distribution characteristic, extend parallel to one another, it is possible to position the lamp units or lighting modules in easy-to-install fashion in a predetermined identical or different plane.
[0010] The lighting device permits a modular design and at the same time to retrofit already existing, installed lighting devices for streets, pathways and the like. A three-dimensional configuration of the lighting modules is not necessary.
[0011] In a preferred embodiment the lamp units are provided with asymmetrically configured lenses so that on a first side, in relation to a central plane, a first partial light beam is emitted in a first dihedral range and on the opposite second side a second partial light beam is emitted in a second dihedral range different from the first dihedral range. The light distribution characteristic of the lamp units thus includes an asymmetric section, where the first dihedral range may for instance be larger than the second dihedral range. The first dihedral range can thus define a preferred direction or a preferred dihedral angle in which the flux and/or the light intensity is bigger than in the second dihedral range.
[0012] In further embodiment the lamp units of the same type and/or of different types are provided with identical lenses. To create a differently oriented asymmetric section of the light distribution characteristic of the lighting module in relation to the orientation of the lighting module, the lenses are rotated in a perpendicular relation to a support of the lighting module. The reference axis is offset in a coaxial or parallel position relative to the optical axis of the lamp units. Thus, merely rotating the lenses permits the generation of a different light distribution characteristic. By modular superpositioning of the light distribution characteristics or of the lighting modules the specified light distribution can be generated.
[0013] In another embodiment, the lamp units are mounted in rows on a common support, forming an elongated lighting module. The lighting module thus advantageously matches the dimension of conventional lighting systems which can therefore be easily retrofitted.
[0014] In another embodiment the lighting modules can be arranged in relation to one another in a linear and/or frame-shaped and/or square, star- or propeller- or cross-shaped pattern so that, as a function of the available or desired dimensions of the lighting device the predefined light distribution is attainable. The needed light distribution can be adjusted by selecting lighting modules of different types.
[0015] In another embodiment the elongated lighting modules of the same and/or different type are combined in a way as to produce an asymmetric light pattern for illuminating a relatively narrow street, with the lighting device placed in a curbside position. The orientation of the lighting modules or lamp units is so chosen that the lighting modules point in the same preferred direction. Advantageously, this permits homogeneous illumination of a predefined longitudinal section of the street.
[0016] In another embodiment the lighting modules are configured for illuminating a street from above the median and are arranged in a way as to ensure symmetrical illumination of both sides of the median in the predefined longitudinal section of the street. To that effect, a first half of the lighting modules points in a first preferred direction and a second half of the lighting modules points in a preferred direction opposite the former.
[0017] In another embodiment the lighting modules are configured for illuminating a place from a central point above the latter are so positioned that the asymmetric light distribution characteristics of the lighting modules point in four different directions, whereby, in relation to a circumferential central axis, lighting modules mutually juxtaposed at a 90° angle point in the respective preferred directions. Advantageously, this essentially permits a rotationally symmetric illumination of a street.
[0018] In another embodiment the lighting modules are configured for illuminating a street corner and are so arranged as to produce two partial light beams which, at a right angle to each other, point in the respective preferred directions. This permits the homogeneous illumination of a junction or a corner area at an intersection.
[0019] In a further embodiment the light sources include LED chips and the frame of the lighting module supporting the LED chips and the lens is shielded with a transparent cover plate. The lighting modules are thus always of the same design, while in relation to its axis of symmetry only the lens may be turned in different positions. Advantageously the lighting module is thus of a relatively simple design.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The following describes exemplified embodiments in more detail with the aid of the drawings in which:.
[0021] FIG. 1 is a perspective bottom view of a lighting device with lighting modules in a frame-shaped arrangement;
[0022] FIG. 2 is a bottom view of the lighting device per FIG. 1 ;
[0023] FIG. 3 is a sectional view of the lighting device per FIG. 2 along line III-III in FIG. 2 ;
[0024] FIG. 4 is a perspective view of the lighting module with a partly cut-out cover plate;
[0025] FIG. 5 is an exploded view of the lighting module;
[0026] FIG. 6 is a sectional view of a lamp unit of the lighting module along line VI-VI in FIG. 2 ;
[0027] FIG. 1 is a sectional view of a lamp unit of the lighting module along line VII-VII in FIG. 2 ;
[0028] FIG. 8 a is a schematic top view of a dual-frame-shaped lighting device;
[0029] FIG. 8 b is a schematic top view of a dual-line-shaped lighting device;
[0030] FIG. 8 c is a schematic top view of a crossform lighting device;
[0031] FIG. 8 d is a schematic top view of a propeller-shaped lighting device;
[0032] FIG. 8 e is a schematic top view of a linear lighting device in a first embodiment;
[0033] FIG. 8 f is a schematic top view of a linear lighting device in a second embodiment;
[0034] FIG. 9 a is a schematic top view of the frame-shaped lighting device per FIGS. 1 to 3 in a first configuration in which the lighting modules point in the same preferred direction;
[0035] FIG. 9 b is a schematic bird's eye view of a longitudinal street area, showing the position of the lighting device;
[0036] FIG. 9 c shows an asymmetric light distribution of the lighting device per FIG. 9 a;
[0037] FIG. 10 a is a schematic top view of the frame-shaped lighting device per FIGS. 1 to 3 in a first configuration, with each two lighting modules pointing in opposite preferred directions;
[0038] FIG. 10 b is a schematic bird's eye view of a longitudinal street area, showing the position of the lighting device;
[0039] FIG. 10 c shows a schematic light distribution of the lighting device per FIG. 10 a;
[0040] FIG. 11 a is a schematic top view of the frame-shaped lighting device per FIGS. 1 to 3 in a second configuration, with each lighting module pointing in a different preferred outward direction;
[0041] FIG. 11 b is a schematic bird's eye view of a longitudinal street area, showing the position of the lighting device;
[0042] FIG. 11 c shows a rotationally symmetric light distribution of the lighting device per FIG. 11 a;
[0043] FIG. 12 a is a schematic top view of the frame-shaped lighting device per FIGS. 1 to 3 in its first configuration, with each two lighting modules pointing in a preferred direction extending at a 90° angle from the other two lighting modules;
[0044] FIG. 12 b is a schematic bird's eye view of a longitudinal street area, showing the position of the lighting device; and
[0045] FIG. 12 c shows an angular light distribution of the lighting device per FIG. 12 a.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] In the following, the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiments and with reference to the drawings.
[0047] FIGS. 1 to 3 depict a first embodiment of a lighting device 1 for streets, pathways and the like. It includes a frame-shaped housing 2 mounted on a pole, not illustrated, via a base 3 . The housing 2 is thus positioned at a predefined distance from the area to be illuminated (street, pathway etc.). In combination with its base 3 the lighting device 1 is mushroom-shaped.
[0048] The lighting device 1 is of a segmented design, comprising multiple straight-linear lighting modules 4 , each positioned on a frame side 5 of the lighting device 1 . The frame sides 5 of the lighting device 1 delimit a square opening 6 . From corners of this frame-shaped housing 2 extend brackets 8 at an angle of about 45° relative to the pole axis or axis of symmetry 9 of the lighting device 1 . On its bottom side 10 the frame-shaped housing 2 has four recesses 11 , each associated with a frame side 5 . Each recess 11 accommodates a lighting module 4 and is shielded by a transparent cover plate 12 .
[0049] As can be seen especially in FIG. 2 a lighting module 4 ′ exhibiting a first light distribution characteristic (of a first type) is arranged at each of, the mutually opposite frame sides 5 of housing 2 while a lighting module 4 ″ having a second light distribution (of a second type) is arranged at each of two other mutually opposite frame sides 5 . The following will describe the configuration of lighting modules 4 , 4 ′, 4 ″ in more detail with reference to FIGS. 4 to 7 .
[0050] FIGS. 4 and 5 illustrate a lighting module 4 ′ of the first type. A support (support board 15 ) is mountable on the outer rim 13 of a tub-shaped lower casing 14 is. The support board 15 is in the form of an elongated, i.e. linear circuit board with eight light sources (LED light sources, LED chips 16 ) surface-mounted in a row and each covered in the main emission direction 17 by a conchiform lens 18 . Each LED chip 16 with an associated lens 18 constitutes a lamp unit 19 of a first type which emits light with a first light distribution characteristic.
[0051] As can be seen in FIGS. 6 and 7 , the lamp unit 19 emits a first partial light beam 21 in relation to a central plane M that intersects an optical axis 20 , in a first dihedral range 22 which in relation to the central axis M is larger than a second dihedral range 23 in which a second partial light beam is emitted on a second side in an opposite location relative to the central axis M. This asymmetric light distribution characteristic is generated by the shape of lens 18 , whereby the light emanating from the LED chip 16 is redirected through reflection and/or refraction, so that the first partial light beam 21 and the second partial light beam 24 produce an asymmetric light distribution characteristic relative to the central plane M. In the lamp unit 19 of the first type the central plane M extends in a transverse direction in relation to the longitudinal orientation of the support board 15 .
[0052] As shown in FIG. 7 , lens 18 is shaped in a way whereby, relative to a central plane N that is rotated by 90° relative to the central plane M, a partial light beam 25 is symmetrically emitted. In the lamp unit 19 of the first type the second central plane N extends in the longitudinal direction of the support board 15 and intersects the optical axis 20 . The central plane M and the second central plane N both extend in a perpendicular direction relative to the support board 15 .
[0053] As shown in FIG. 6 , lens 18 features on one side a first flat wing 26 and a second steep wing 27 . The relatively flat first wing 26 results in the emission of a relatively wide first partial light beam 21 in the first dihedral range 22 (65°). The relatively steep second wing 27 leads to the emission of the second partial light beam 24 in the second dihedral range 23 (40°). The first partial light beam 21 is thus emitted at a larger angle relative to the central plane M than the second partial light beam 24 . The lamp unit 19 of the first type exhibits a preferred direction V toward a front face of support board 15 which is faced by the relatively flat wing 26 of lens 18 . The first partial light beam 21 and the second partial light beam 24 form an asymmetrical section of the light distribution characteristic relative to the central plane M.
[0054] A lamp unit 28 of a second type differs from lamp unit 19 of the first type in that lens 18 is positioned at a 90° angle relative to a reference axis of support board 15 . The reference axis extends coaxially with the optical axis 20 of lamp unit 28 . As shown in FIG. 2 , the rows of lamp units 28 of the second type form lighting module 4 ″ of the second type and the flat wings 26 of the corresponding lenses 18 point in the same preferred direction V as the flat wings 26 of lenses 18 of lamp unit 19 in lighting modules 4 ′ of the first type. The result is a lighting device 1 with an asymmetric light distribution pattern (light distribution characteristic) serving to illuminate a street 29 , the lighting device 1 in this case positioned in a transitional area between the street 29 and a bicycle path/sidewalk 30 , as indicated in FIG. 9 a , 9 b . FIG. 9 b shows the pole axis of lighting device 1 , FIG. 9 c illustrates the asymmetric and relatively homogeneous light distribution L 1 of lighting device 1 .
[0055] FIGS. 2 and 3 show that the optical axes 20 of lamp units 19 of the first type and of lamp units 28 of the second type extend parallel to each other. The support boards 15 of lighting modules 4 , 4 ′, 4 ″ extend in a common plane perpendicular to the pole axis 9 and perpendicular to optical axis 20 . Thus, lighting modules 4 , 4 ′, 4 ″ essentially extend in a two-dimensional space, essentially parallel to a longitudinal area 31 of the street 29 that is illuminated by the light beam of lighting device 1 .
[0056] It will be evident that the lamp units 19 , 28 incorporate the same components, these being identical LED chips 16 and the same lenses 18 . The only difference is that the lenses 18 are positioned at a 90° angle to the reference axis 20 . In an alternative embodiment, not illustrated, other lighting modules may contain lamp units whose lens 18 is turned 180° relative to lens 18 of lighting module 4 ′ of the first type. As another alternative, lighting modules 4 , 4 ′, 4 ″ may only in part contain lamp units of the same type. For example, lamp units of different types may be used in a relative long lighting module.
[0057] In the exemplified embodiments here described, the lighting modules 4 , 4 ′, 4 ″ each contain lamp units whose lenses 18 are in the same position relative to support board 15 of lighting module 4 , 4 ′, 4 ″.
[0058] In an alternative embodiment of a lighting device 1 ′ per FIGS. 10 a to 10 c , the frame-shaped housing 2 —as in lighting device 1 —may be equipped with two lighting modules 4 ′ of the first type and two lighting modules 4 ″ of the second type in which case, however, the lighting modules 4 ′ and, respectively, 4 ″ positioned on opposite frame sides 5 , point in opposite preferred directions and not—as in lighting device 1 —in the same preferred direction V. As shown in FIG. 10 a , while lighting modules 4 ′, 4 ″ mounted on opposite frame sides 5 are of the same type, they are turned 180° relative to pole axis 9 , so that by superpositioning light beams with equally distributed preferred directions V are emitted in two opposite directions. This lighting device 1 ′ would preferably be positioned above the median 32 of street 29 , with the preferred directions V extending in a transverse relation to the median 32 for a homogeneous illumination of the longitudinal area 31 of street 29 . FIG. 10 c illustrates a light distribution L 2 obtained with lighting device 1 ′.
[0059] In another embodiment of a lighting device 1 ″ per FIG. 11 a to 11 c, the frame-shaped housing 2 , unlike that in lighting device 1 , may be equipped with lighting modules 4 ″ of the second type. These lighting modules 4 ″ will be positioned in a way whereby their preferred directions V point outward away from the pole axis 9 , so that lighting device 1 ″, preferably located at a central point 33 of a place 34 , can serve to homogeneously illuminate the latter as a function of the light distribution L 3 . The preferred direction V differs for each of the lighting modules 4 ″. Advantageously this permits a rotationally symmetric illumination of a place 34 .
[0060] In another embodiment of a lighting device 1 ′ as shown in FIGS. 12 a to 12 c , two lighting modules 4 ′ of the first type and two lighting modules 4 ″ of the second type may be employed, in which case there will only be two preferred directions V which in relation to the pole axis 9 are positioned at a 90° angle relative to each other. Advantageously this permits homogeneous illumination of a road junction or of the corner 35 of a street 29 as a function of the light distribution L 4 as shown in FIG. 12 c.
[0061] In another embodiment according to FIG. 8 a , two frame-shaped lighting devices 1 ′ may be combined to form a dual-frame lighting device 36 . The two frame-shaped lighting devices 1 ′ are positioned on two sides of pole axis 9 and may be attached to the pole by means of holding devices 37 . This lighting device 36 is preferably used for relatively wide streets, especially multi-lane streets, with the lighting device 36 positioned above the median 32 .
[0062] In another embodiment per FIG. 8 b , a dual linear lighting device 38 may be provided, in which case two lighting modules 4 will be mounted on both sides of pole axis 9 , extending parallel to each other.
[0063] In another embodiment as shown in FIG. 8 c , four lighting modules 4 may be installed in a cross like form arrangement at a 90° angle from one another so as to form a cross-shaped lighting device 39 .
[0064] Alternatively, a propeller-shaped lighting device 40 can be created by positioning three lighting modules 4 around the pole axis at a 120° angle.
[0065] In another embodiment as shown in FIG. 8 e , a linear lighting device 41 may be provided by sequentially positioning multiple lighting modules 4 in a longitudinal direction.
[0066] In another embodiment of a linear lighting device 42 , the lighting modules 4 may merely by be positioned in the form of a parallel flush-mounted array.
[0067] The modular concept permits a simple adaptation to given lighting requirements. In particular, with only two different lighting modules 4 ′, 4 ″ it is possible to create various configurations of lighting devices.
[0068] The lighting device can be employed not only for street lighting but also for illuminating industrial facilities or living rooms. For example, the lighting device according to the invention can be used for illuminating moisture- and explosion-proof rooms, in a kitchen area, on furniture and the like.
[0069] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
[0070] It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide lighting devices. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.
[0000]
LIST OF REFERENCE NUMERALS
1, 1′, 1″, 1′″
lighting device
2
frame-shaped housing
3
base
4, 4′, 4″
lighting modules
5
frame side
6
opening
7
8
brackets
9
axis of symmetry
10
bottom side
11
recesses
12
cover plate
13
rim of opening
14
lower casing
15
support board
16
LED chips
17
main emission direction
18
lens
19
lamp unit
20
optical axis
21
first partial light beam
22
first dihedral range
23
second dihedral range
24
second partial light beam
25
light beam
26
first flat wing
27
second steep wing
28
lamp unit
29
street
30
bicycle path/sidewalk
31
longitudinal street area
32
median
33
central point
34
place
35
corner
36
lighting device
37
holding devices
38
lighting device
39
lighting device
40
lighting device
41
lighting device
42
lighting device
43
44
45
46
47
48
L1
light distribution
L2
light distribution
L3
light distribution
L4
light distribution
M
central plane
N
central plane
V
preferred direction | An illumination device comprising a housing positionable at a distance from an area to be illuminated and having at least one lighting module, on a support in the housing, that has lighting units having the same light distribution characteristics. Each of the lighting units contains lighting elements and associated lenses arranged in front of the same in the light-emitting direction. Different lighting modules may include lighting units having different light distribution characteristics, while the lighting units have optical axes running parallel to each other. At least one lighting unit is configured such that its light distribution characteristics have at least one asymmetrical section relative to a central plane of the lighting unit. | 5 |
BACKGROUND OF THE INVENTION
The invention relates to a road or reflector post manufactured of plastic material.
Road posts are known of an extruded body which has open ends, resulting from the extrusion process. On the pose end which is to constitute the upper end of the post a separate cap is placed which seats within the hollow upper end through a force fit. This cap serves among other purposes to permit the post to be driven into the ground without damaging it. However, the separate cap causes additional manufacturing and assembling cost.
SUMMARY OF THE INVENTION
The present invention aims at providing a road post which may be integrally manufactured and is sufficiently strong with minimal material consumption.
This is achieved according to the invention in that a post comprising two identical dish-shaped halves is provided. Each half is provided at its upper edge, upstanding from the dish bottom and to one side of the longitudinal symmetry plane of the dish, and to the other side of this plane with a groove adapted for engagement with the blade-shaped projection of the other dish-half.
When two halves are placed one on top of the other with one half turned upside down and their hollow sides opposite to each other, the blade-shaped projections may be snapped in the then opposing grooves.
Preferably to increase the rigidity and strenght of the structure it provided, closely adjacent to, within parallel to the outer edge of a dish-shaped half webs projecting from two post halves are snapped together the edges of the webs mutually engage so that they may be welded together under the application of heat. Molten and sagged material edges are generated by the welding process which bond together, invisible from the exterior of the post so that the appearance of the post is not impaired thereby.
In order to obtain sufficient strength and rigidity with small material thickness each post half is provided with reinforcement and/or rigidifying ridges in both or either of the longitudinal and the transverse directions.
Since the post head must permit the imparting of blows thereto without the generation of cracks or failures it is advantageous to provide additional reinforcement ridges formed at the one end of the road post, these ridges extending continually from a smaller height in the remainder of the dish to the outer edge of the upstanding wall of this post upper end. The longitudinal and transverse ridges in the remaining portion of the dish do not continue to the interface of the halves because then it is possible, as is often usual, to slide the post as a sheath onto a wooden supporting bar or standard which is secured in the ground, when providing the posts alongside the roads.
For that application the dish if formed at the longitudinal end remote from the post upper end without an upstanding outer edge portion.
One obtains a smoother exterior and less possibility of damage to any reflectors served thereon when the dish bottom has formed therin a recessed portion for receiving the reflector.
It is also possible to secure the road post according to the invention independently, without a wooden inner supporting post, in the ground. The dish is provided at its longitudinal end remote from the upper end with an outer edge portion which is shaped substantially with saw-tooth barbs, symmetrical with respect to the longitudinal symmetry plane of the dish and terminating in a sharp point, as a so called Christmastree foot or base.
The invention is further illustrated below with references to the drawing, which shows two embodiments of the road post according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view of a post according to the invention,
FIG. 2 is a plan view of the interior of a dish half,
FIG. 3 shows incross-section two dish halves placed on top of each other, prior to their mutual connection,
FIG. 4 is a partial cross-section along line IV--IV of FIG. 2,
FIG. 5 shows a plan view a foot portion for a road post and,
FIG. 6 is partial cross sectional views taken along line VI--VI of FIG. 2.
DESCRIPTION OF THE INVENTION
The road post 1 as shown in FIG. 1 comprises two dish halves 2, mounted to each other; the connecting seam 3 showing that the post comprises two symmetric dish halves. To the front of the post a white reflector 4 has been secured through connection means 5 in a recess 6 on the outer surface of the one dish half 2, while in completely similar manner a red reflector has been secured to the back of the post (which cannot be seen in the drawing).
FIG. 2 shows a plan view of the interior of a post half 2. This post half is dish-shaped and has upstanding side walls 7 a head or end wall and a bottom wall 9 serving as the face of the post.
The lower end of the dish 2, situated at the lower end of the dish half shown in FIG. 2, is not illustrated in FIG. 2 but has in the first embodiment an open end, that is the bottom wall 9 together with both side edges end 7 in a plane perpendicular to the plane of the drawing, and also perpendicular to the longitudinal axis 10 of the dish. In this embodiment the plastic post as shown is in effect a sleeve which may be mounted on a supporting wooden inner post or bar, which post or bar in its turn is secured in the ground. The plastic post of this invention may extend to or below ground if desired. The lower end of the dish according to FIG. 2 may also be shaped according to FIG. 4., so that the plastic post is self supporting and may itself be driven into the ground. This relates to the second embodiment which will be discussed later on.
The dishes 2 are integrally formed through die casting in a mould in which the somewhat convex shaped dish bottom 9, the upstanding side edges 7 and the head wall 8 are formed.
As appears from FIG. 3 the edge of one side wall 7 of each dish is provided with a blade-shaped projection 11, being a continuation of said edge, while the edge of the other side wall 7 is provided with a groove 12 complementary to this projection. The blade-shaped projection or the groove respectively continue from the side wall up along the edge of the head or end wall 8; the projection as well as the groove terminating at the positon of the longitudinal axis 10.
When two dish halves 2 are placed with the hollow sides opposite to each other, as is shown in FIG. 3, by snapping the projection 11 in the opposing groove 12 bothe dishes become mutually connected from the road post. Of course the dimensions of the projection as well as of the groove are such that these parts may be engaged through the resiliency of the plastic as used so that thereby a certain retaining force is obtained.
In order to make the connection between both dish halves a web 13 extending adjacent to within and parallel to each outer side wall 7 and continuing along the head end wall 8 has been moulded integrally with the dish bottom and projecting therefrom. The edge of the webs of the two oppositely placed dishes meet each other when the dish halves are placed on top of each other, for which purpose the height of the webs has been chosen correspondingly. Through heat applied to the webs, the edges of webs are mutually welded, in mirror image, the material that has been molten hardens again on the interior of the post and 6 not visible on the exterior of the post.
For reinforceing and rigidifying the post further, longitudinal ridges 14 and transverse ridges 15 may be moulded integrally with the dish halves 2, upstanding from the bottom. Of course these ridges may have a different spacing and a different number than have been shown in the drawing.
Since the head of the post, at the position of the head end wall 8, must be able to receive blows when the plastic post is placed on the wooden inner post alternatively or in the ground, additional ridges 16 are formed as seen in FIG. 6 on the interior of the head end wall 8, wherein height may gradually increase from the transverse ridge 15 which is closest to the head end wall 8 to this head end wall 8 or the section of the welding web 13 parallel thereto respectively.
The recess 6 is formed in the face of the dish bottom 9, and is adapted to receive the reflectors 4 discussed above.
FIG. 5 shows a second embodiment for the base or foot of the post serving to place the post directly in the ground. In this embodiment a barbed foot 17 is formed by continuing the side walls 7 of the dish according to a converging stepped pattern, whereby a so called Christmastree foot or turbine blade foot is obtained. The welding web 13 likewise continues in the foot portion corresponding to the Christmastree contour parallel to the corresponding portions of the outer sides 7. At the point of the salient steps the welding webs at both sides of the longitudinal axis 10 are mutually connected as a continuous ridge 18 and additional longitudinal ridges are provided at these positions.
Preferably locating a mark 19 is provided in the form of a circumferential raised ridge on the exterior surface of the dish, perpendicular to the longitudinal axis 10, so that it may be seen how deep the post must be driven into the ground. When the ridge 19 is flush with the ground surface the portion of the post extending upwardly from the ground surface has the required height.
As a suitable plastic material for manufacturing the posts according to the invention the material Keltan may be mentioned, which is supplied to the market by DSM (de Staatsmijnen, a Dutch firm).
It will be clear that modifications within the field of the invention may be made to the embodiments as shown. | A road post or reflector formed of two identical disk shaped members each having a bottom wall, two longitudinal side walls and an end wall at at least one end. One side wall and half of the end wall having a projection and the other wall and other half of the endwall having a groove enabling the two members to be assembled by snap engagement. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX
[0003] Not Applicable
BACKGROUND OF THE INVENTION
[0004] Field of the Invention
[0005] This invention pertains to USPTO Cooperative Patent Classification (CPC) ‘B’—performing operations, transporting; B25B—tools or bench devices not otherwise provided for, for fastening, connecting, disengaging or holding; B05B—spraying apparatus; B27G—accessory machines or apparatus, tools, safety devices e.g. those for saws.
[0006] All listed prior art found does not address the functionality to restrain or hold a fast-flow high-pressure spraying device similar to this invention. Below is a list of some of the prior art found:
20150298297 Clamping Method & Apparatus B25B 1/24 20150266165 Clamp Head B25B 5/16; 5/10 20150252855 Torque Limiting Device B25B 23/1427; A61B 20150246430 Clamping Assembly B25B 5/06; B25J 15/008 20150202699 Apparatus for Manipulating Tubular and Round Section Objects 20150183093 Apparatus & Method for Mechanical Vice 20150174738 Bar Clamp & Bar Clamp Assembly B25B 5/102; 5/103 20150151392 Clamp Apparatus 20150137440 Clamp Apparatus B25B 5/08; 1/04 20150101463 Apparatus for Holding and Applying Torque to a Nut B25B 23/108; 13/54 20150054210 Centric Clamping Vice B25B 1/02; 1/103 20150053053 Torque Limiting Tool and Method for Using Same B25B 23/1415 20150042027 Clamp B25B 1/20 20140353898 Clamping Device, particularly a clamping module B25B 1/18; B23Q 1/262; 1/44 20140346725 Portable Work Holding Device and Assembly B25B 1/2484; 1/02; B60R 11/00
[0022] The apparatus is designed to hold securely a fast-flow high-pressure liquid spraying device e.g. fire fighter's fast-flow high-pressure water hose. The apparatus is intended to supplement the intense control and strength needed to commandeer command and safely operate such devices while in use for extended periods of time.
[0023] The constant and continual demand to grasp, hold on to and control a fast-flow high-pressure flexible liquid spraying device e.g. a fast-flow high-pressure washing hose can be exhausting and hazardous during an elongated laborious operation requiring significant physical strength and intense exertion that can possibly create productivity gaps and safety risks during critical campaigns.
[0024] Therefore, it is desirable to develop a transportable torque (pressure) absorbing holding apparatus that acts as an additional resource to hold steady and secure a fast-flow high-pressure liquid spraying device without compromise.
BRIEF SUMMARY OF THE INVENTION
[0025] Briefly described, one aspect of the present disclosure provides an apparatus designed to securely hold a fast-flow high-pressure liquid spraying device e.g. fire fighter's fast-flow high-pressure water hose during high impact, high pressurized liquid spraying operations. The device includes a handle that is ergonomically shaped to enable the apparatus to be grasped easily and comfortably by an individual for easy movement and set-up.
[0026] To provide an effortless portable experience, the transportable holding apparatus collapses into a near flat mechanism utilizing two wheels attached to the base back cross bar for easy navigation and maximum maneuverability. Opposite the base back cross bar of the device attached to the base bar is the ergonomically shaped handle positioned between the two front legs which are positioned and shaped for maximum balance and sturdiness to provide the apparatus stability during operations. A heavy duty cross body strap is used to wrap around the transportable holding apparatus when folded into a near flat position for additional safety precautions during transport and storage.
[0027] The transportable holding apparatus is designed to securely hold and immobilize a fast-flow high-pressure liquid spraying device e.g. fire fighter's fast-flow high-pressure water hose using a holding clamp harness with elongated neck inserted into the forward cylinder to absorb torque generated by the force of the liquid spraying device during start-up and operations. The transportable holding apparatus can be used to grasp and immobilize, hold on to and maintain the direction and position of a spraying device of any size, even though the design is targeted for the high power, high pressurized, fast flow liquid spraying devices which require substantial strength to manage and maneuver for significant periods of time and in hostile environments e.g. firefighting of all natures, wildfires in hazardous terrains, environmental cleaning and separation operations, pressure washing and cleaning of chemicals, oil & gas holding tanks, etc.
[0028] The transportable holding apparatus' horizontal forward cylinder is adjustable. The horizontal forward cylinder releases, lifts and locks at various angles via its cylindrical rollers attached to the base bar of the apparatus. For additional stability, the horizontal forward cylinder is reinforced and supported by a concave intersection in which the back support cylinder locks into place at the mid-section of the horizontal forward cylinder. The cylinder rollers attached to both the horizontal forward cylinder and back support cylinder allow the transportable holding apparatus to be folded flat or positioned at an appropriate angle to achieve the desired liquid spraying arc. The horizontal forward cylinder's hollow cavity contains internal shafts that support elevation of the spraying device to achieve and support the desired liquid flow arc. After the desired height and direction is attained, the holding clamp harness is secured in place using the horizontal forward cylinder spring key and lock.
[0029] The holding clamp (harness) which contains a soft flexible inner lining attaches directly to the upper neck of the outer wall of the liquid spraying device closest to the head, opening or nozzle and is tightened securely in place. The holding clamp harness' outer wall is designed to overlap creating an alignment of its apertures to form a secure jacket engulfing the liquid spraying device snugly but allowing leniency in the grasp to accommodate for friction. The holding clamp (harness) apertures are securely clasped via fasteners. The elongated clamp rod of the holding clamp (harness) is inserted into the internal shaft of the forward cylinder and positioned toward the target using the directional panning plate. The apparatus is designed to be an additional resource much like that of the ‘12 th man theory’ for an eleven-a-side sports game team e.g. American football.
[0030] Attached to the horizontal forward cylinder can be a light kit which raises, lowers and turns 360 degrees. The light is attached via heavy duty strap and closure.
[0031] Numerous other aspects, features, and advantages of the present invention will be made apparent from the following detailed description together with the drawings and figures.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0032] The drawings illustrate the best mode currently contemplated of practicing the present disclosure. The drawings:
[0033] FIG. 1 is an overall view of the one embodiment of a transportable holding apparatus constructed according to the present disclosure;
[0034] FIG. 2 is a side view of the one embodiment of a transportable holding apparatus with wheels, forward and back cylinders, and locking mechanisms constructed according to the present disclosure;
[0035] FIG. 3 is a side view of the one embodiment of a transportable holding apparatus with brace plates constructed according to the present disclosure;
[0036] FIG. 4 is a side view of the one embodiment of a transportable holding apparatus showing where various members of the apparatus are attached to each other constructed according to the present disclosure;
[0037] FIG. 5 is an overall view of the transportable holding apparatus of FIG. 1 holding a fast-flow high-pressure liquid spraying device e.g. fire fighter's fast-flow high-pressure water hose;
[0038] FIG. 6 is a side view of the apparatus of FIG. 1 in a collapsed (folded) vertical and horizontal perspective bound by heavy duty safety belts.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Referring now in detail to the drawing figures, wherein like reference numerals represent like parts throughout the several views, one embodiment of a apparatus constructed according to the present disclosure is illustrated generally in FIG. 1 . The apparatus 30 in the illustrated embodiment is a rigid frame formed of a length of a suitable durable material, such as metal, among others beginning with an elongate base bar 1 adapted to rest upon a level surface wherein said base bar 1 is perpendicularly attached at one end, the rear side 50 , to the mid-section of the base back cross bar 27 and at the opposite end of base bar 1 , the front side 40 includes two legs at a sufficient angle, the left leg 26 and right leg 25 is of equal length. The elongated base bar 1 comprises a front side 40 and a rear side 50 . Between the base bar right leg 25 and base bar left leg 26 is an ergonomically designed handle 2 . The handle 2 can be formed of any suitable material, such as a metal, plastic or wood capable of enabling the apparatus 30 to be transportable in its intended manner. Additionally, the handle 2 can have any desired axial and/or cross-sectional shape suitable for the intended purpose of the apparatus 30 . The handle 2 can also include any suitable structure (not shown), such as including finger wedge or grip (not shown) that assists the user in retaining a grasp on the handle 2 . The finger wedge or grip is formed of any conventional grip material, such as leather or foamed materials, among others, in order to provide additional comfort to the hand of the individual grasping the handle 2 in addition to that afforded by the shape of the handle 2 . In the illustrated embodiment, the handle 2 has an ergonomic shape, which can be shaped in an arc similar to a handle used for a cross bow.
[0040] Further, in the illustrated embodiment, extending from the rear of the base back cross bar 27 are wheels 3 generally spaced from either end of the base back cross bar 27 which makes contact with the ground or floor surface when the apparatus 30 is lifted upward or to a horizontal position for transport maneuverability. Attached to base bar 1 at the front side 40 and rear side 50 of the elongated pedestal is a set of cylinder rollers 5 which allows the rigid forward horizontal cylinder 6 and back support cylinder 7 to rotate up and down when the brace plates 8 are not in a permanent or locked position. On the upward facing side of base bar 1 are two locking portions 4 which interconnect the horizontal forward cylinder 6 and back support cylinder 7 to the base bar 1 when the apparatus 30 is folded for transport or storage. The locking portion 4 can be any suitable mechanism capable of securely engaging and alternatively releasing the forward horizontal cylinder 6 and back support cylinder 7 to and from the base bar 1 . The locking members (not shown) on the horizontal forward cylinder 6 and back support cylinder 7 are capable of being engaged by the locking portion 4 to be secured to base bar 1 . In the illustrated embodiment, the locking portion 4 on base bar 1 inserts into ridges of the locking members (not shown). In addition, the locking members (not shown) can be formed integrally with the horizontal forward cylinder 6 and back support cylinder 7 or can be attached thereto.
[0041] Now referring to FIGS. 2 and 3 , in the illustrated embodiment is a generally forward horizontal cylinder 6 extends upwards whereby the forward horizontal cylinder 6 is attached to the upward facing side of base bar 1 at the front side 40 of the elongated base bar 1 at 35 . A back support cylinder 7 extends upwards and comprises an elongated cylinder having opposing ends generally fixed perpendicularly to the midpoint of the forward horizontal cylinder 6 at one end 37 and at the rear side 50 of the elongated base bar 1 at the other end 36 . A brace plate 8 is attached on the right and left sides of the forward horizontal cylinder 6 of the elongated base bar 1 at the front side 40 . A brace plate 8 is attached on the right and left sides of the back support cylinder 7 of the elongated base bar 1 at the rear side 50 at 36 .
[0042] Now referring to FIG. 4 , the forward horizontal cylinder 6 is cavernous to include two internal shafts, an upper 12 and lower 11 both comprising rigid material. The upper internal shaft 12 is of a narrower diameter than the lower internal shaft 11 whereby the upper internal shaft 12 fits inside the hollow shell of the lower internal shaft 11 and extends up and down. The lower internal shaft 11 having one end 42 securely fixed to the bottom of the forward horizontal cylinder 6 whereby the opposite upper end 46 of the lower internal shaft 11 is the opening receptacle for the upper internal shaft's lower end 44 . The upper internal shaft 12 is generally sprinkled with through holes 15 throughout its body while only the upper half of the lower internal shaft 11 contains through holes 15 to lock the internal shaft height. Top center of the forward horizontal cylinder 6 is the forward cylinder top through aperture 10 which allows the neck of the upper internal shaft 12 to be extended up and beyond the cavity of the forward horizontal cylinder 6 . Situated at the upper end 48 of the upper internal shaft 12 is a winding connection 14 to receive and hold the holding clamp 24 in place in the cavity of the forward horizontal cylinder 6 .
[0043] In the illustrated embodiment, the holding clamp 24 is supported by an elongate clamp rod 20 formed of a suitable length of a durable rigid material, such as metal or plastic, among others. The holding clamp 24 and elongate clamp rod 20 is secured as one in a suitable manner using any suitable securing or fixation member, such as a pin or a screw. In the illustrated embodiment, the holding clamp 24 is secured to elongate clamp rod 20 using a screw (not shown) as the securing member. The elongate clamp rod 20 raises and lowers via the winding connection 14 at the upper end 48 of the upper internal shaft 12 . A vertically disposed holding clamp 24 circular in shape when generally attached is secured at the upper end 52 of the elongate clamp rod 20 . The vertically disposed holding clamp 24 includes an inner layer, the inner clamp gripping harness 18 comprising a soft suitable material which includes but is not limited to foam covered with vinyl or other materials and an outer member 17 comprising semi-flexible rigid materials such as metal or plastic, among others. The inner clamp gripping harness 18 is made of materials that will not scratch, puncture or damage and will swathe the outer wall of the fast-flow high-pressure spraying device when pressure is applied against the harness. To facilitate the engagement of the outer member 17 with the inner clamp gripping harness 18 both have a number of apertures 19 disposed along the length of the outer member 17 and the inner clamp gripping harness 18 . The outer member 17 apertures 19 adjusts to align with apertures 19 of the inner clamp gripping harness 18 to create a secure restraint for the fast-flow high-pressure spraying device secured in a suitable manner using any suitable securing or fixation member, such as a pin, bolt or a screw. In the illustrated embodiment, the holding clamp 24 is secured to the fast-flow high-pressure spraying device using a bolt 60 (see FIG. 5 ) as the securing member.
[0044] The panning plate 21 comprising rigid materials such as metal or plastic, among others is attached at the upper end 52 of the elongate clamp rod 20 . The panning plate 21 allows the user to easily make minor adjustments by swiveling the panning plate 21 to the right or left to make height and direction changes to the holding clamp 24 . The elongate clamp rod 20 is locked into place by inserting the spring key 22 through the forward horizontal cylinder 6 front through hole (not shown) encompassing the upper internal shaft 12 , the elongate clamp rod 20 and the lower internal shaft 11 continuing through the forward horizontal cylinder 6 back through hole (not shown). The spring key 22 is fortified by attaching the spring key hook 23 . The spring key 22 and spring key hook 23 comprising rigid materials such as metal or plastic, among others. In the shown preferred embodiment, the rigid frame with a base bar 1 adapted to rest upon a level surface, such as a floor or ground, base back cross bar 27 , left leg 26 and right leg 25 include suitable nonskid material (not shown) such as rubber but not limited to rubber applied to the bottom of each member providing firm grip once the frame is at rest.
[0045] In operation, as FIG. 5 illustrates the apparatus 30 with vertically disposed holding clamp 24 in a closed position thereby securely embracing and holding a fast-flow high-pressure liquid spraying device such as a fireman's water hose. The fast-flow high-pressure liquid spraying device is restrained from moving forward beyond the forward horizontal cylinder 6 and is secure in the direction in which the user prefers the flow of liquid to remain constant and consistent.
[0046] FIG. 6 illustrates the apparatus 30 folded and lying flat horizontally on a level surface and upright vertically prepared for transport with heavy duty belt 54 securing its parts as an added safety precaution.
[0047] Various other embodiments of the present invention are contemplated as being within the scope of the filed claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.
[0048] While preferred embodiments have been shown and described, it will be understood that it is not intended to limit the disclosure, but rather is intended to cover all modifications and alternate methods and apparatus within the spirit and scope of the invention as defined in the claims. | A multipurpose transportable holding apparatus to grip securely a fast-flow high-pressure liquid spraying device e.g. fire fighter's fast-flow high-pressure water hose. The holding apparatus supplements the intense control and strength needed to commandeer command and safely operate fast-flow high-pressure liquid spraying devices unaided while in use for extended periods of time. The apparatus can be considered the twelfth person of an eleven member team during an elongated laborious exhausting and hazardous campaign requiring significant physical strength and intense exertion e.g. fighting fires or pressure washing in unsafe and hazardous environments. The torque absorbing holding apparatus holds steady and secure a fast-flow high-pressure liquid spraying device providing consistent uniform application and enforcement for the spraying device without compromise. | 0 |
This application is a continuation of prior application Ser. No. 08/083,543 filed on Jun. 30, 1993, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a camera capable of selecting one of a plurality of shooting aspect ratios.
2. Related Background Art
Conventionally, as described in Japanese Laid-Open Patent Application No. 62-163033, a camera which has a trimming shooting mode for designating to print only a partial region in a shooting field, and cancels the trimming shooting mode by a lens change operation, a film change operation, an operation of a main switch (SW), and the like, is proposed.
However, in this prior art, since trimming control means is canceled using the camera state as a signal, if a camera capable of switching a shooting aspect ratio is examined in place of the above-mentioned camera, the camera suffers from the following drawbacks:
(i) Even when a shooting operation is to be continuously performed at the same aspect ratio, the setting value of the aspect ratio is undesirably reset in accordance with the camera state.
(ii) Since the aspect ratio is not reset in units of frames in a single film, an operator cannot be prevented from forgetting to reset the aspect ratio in units of frames. (iii) Since an operator cannot select an aspect ratio as an initial value, an aspect ratio normally used by the operator is undesirably fixed.
SUMMARY OF THE INVENTION
One aspect of the application has as its object to provide a camera, which can select a shooting aspect ratio in units of frames of a film or continuously.
In order to achieve the above object, one aspect of the application provides a camera wherein a shooting aspect ratio is selected and set in setting means, the set aspect ratio information is recorded in each shooting frame, prohibiting means for prohibiting recording of the set aspect ratio information when the camera is set in a predetermined state is arranged, and the operation of the prohibiting means can be manually selected.
Under the above-mentioned object, one aspect of the application provides a camera wherein after the prohibiting means prohibits recording of the set aspect ratio information, specific aspect ratio information is recorded in each frame independently of the set aspect ratio information.
Other objects of the present invention will become apparent from the following description of the embodiment taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 1C are views for explaining a plurality of aspect ratios;
FIGS. 2A and 2B are views showing aspect ratio information recorded on a film;
FIG. 3 is a schematic perspective view showing an internal arrangement of a camera used in the present invention;
FIG. 4 is a block diagram showing the first embodiment of the present invention;
FIG. 5 is a flow chart showing an operation of a microprocessor in the embodiment shown in FIG. 4; and
FIG. 6, which consists of FIG. 6A and 6B, is a flow chart showing an operation of the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1A to 1C show differences of printed regions of three different aspect ratios.
FIG. 1A shows a region printed in a print mode when an aspect ratio switching value "H" is selected, and a shooting operation is performed. In FIG. 1A, the aspect ratio is about 1:1.8, and the printed region almost corresponds to the entire shooting field of one frame of a film. FIG. 1B similarly shows a region printed in the print mode when an aspect ratio switching value "L" is selected, and a shooting operation is performed. In FIG. 1B, the aspect ratio is about 1:1.5, and the right and left regions of a frame are cut as compared to the aspect ratio "H". FIG. 1C shows a region printed in the print mode when an aspect ratio switching value "P" is selected, and a shooting operation is performed. In FIG. 1C, the aspect ratio is about 1:2.8, and the upper and lower regions of a frame are cut.
Information indicating one of these aspect ratio switching values "H", "L", and "P" is recorded in an information storage portion corresponding to each frame of a film, and a print operation is performed according to the recorded information, thus obtaining a print having a desired aspect ratio.
FIGS. 2A and 2B show aspect information recorded on a film.
FIG. 2A shows a case wherein shooting operations of all frames of a single film are performed at the same aspect ratio. FIG. 2B shows a case wherein shooting operations are performed at different aspect ratios in a single film. Each of FIGS. 2A and 2B shows some frames of a film.
In FIG. 2B, the 11th and 12th frames are subjected to shooting operations in the format "H", the 13th frame is subjected to a shooting operation in the format "P", and the 14th to 16th frames are subjected to shooting operations in the format "H" again. In this case, a region to be exposed on each frame of a film is exposed on the frame as a region having a maximum one of the three different aspect ratios (in this case, the format "H"), and the type ("H", "L", or "P") of aspect ratio is recorded as information on an information storage portion corresponding to the frame. In a print mode, the recorded information (the type of aspect ratio) is read, and the region on the corresponding frame is printed at an aspect ratio corresponding to the read information, thus obtaining a desired print.
FIG. 3 is a schematic perspective view showing an internal arrangement of a camera used in the present invention. The camera shown in FIG. 3 comprises a feed photoreflector R for detecting perforations P of a film F and feeding the film by a predetermined distance, a film feed motor M arranged in a spool, a gear train G for performing deceleration of the film, and switching between a wind-up and rewind operations, a rewind fork K, a film cartridge C, the above-mentioned film F on which a magnetic layer is coated at the base side, a magnetic track T (magnetic storage portion) for recording data such as an exposure condition, a frame number, and the like as magnetic information, perforations P corresponding to the shooting field, a magnetic head H for writing and reading out information on or from the magnetic track T on the film F, and a pressing pad D for pressing the film F against the magnetic head H.
FIG. 4 is a block diagram showing an embodiment of the present invention. The camera shown in FIG. 4 includes a microprocessor 1 for controlling the camera, a photometric circuit 2, a distance measuring circuit 3, a shutter control circuit 4, and an aperture control circuit 5, which are constituted by known circuits. The cameras also includes a photometry/distance measurement start switch (SW1) 6 and an exposure start switch (SW2) 7, which are respectively turned on at the first and second stroke positions of a release button. The camera further includes a main switch 8, a magnetic recording circuit 9 for writing information on the film, a magnetic head 10 (H in FIG. 3), a back lid open/close detect switch 11, and a select switch 12 for selecting an aspect ratio. Every time the select switch 12 is pushed, the aspect ratio changes like "H", "L", and "P" in turn, and the selected aspect ratio is displayed on a display circuit 21. The camera also includes a switch 13 for selecting whether or not the reset operation of the setting value of the aspect ratio is performed, a select switch 14 for selecting an initial setting value of the aspect ratio, a motor drive circuit 15 for feeding a film 16, a motor 17 (M in FIG. 3), a lens detect switch 18 for detecting that a lens is mounted, a patrone detect switch 19, a film number reader 20 for reading a film number recorded on a film cartridge in the form of, e.g., a bar code, and a display circuit 21 for displaying the setting value of the selected aspect ratio, the frame number, a shutter control value, an aperture value, and the like.
FIG. 5 is a flow chart showing the basic operation of the microprocessor 1 according to the first embodiment of the present invention. The camera shown in FIG. 3 is a pre-wind type camera, which takes up all frames of a film from a cartridge on a take-up spool, and feeds the film frame by frame into the cartridge in a shooting operation. It is assumed that, before execution of the flow chart of FIG. 5, the cartridge is set in the camera, and the pre-wind operation is already performed. In the operation shown in FIG. 5, one of the aspect ratio formats "H", "L", and "P" is selected. In this selection, one of the formats "H", "L", and "P" is selected upon operation of the switch 12, and the selected format information is set (step 101). Then, whether or not the aspect ratio is reset to an initial setting value for each frame is selected. This selection is made by the operation of the switch 13, and whether or not the reset operation is performed is set (step 102). If neither of the photometry/distance measurement start switch 6 (SW1) and the exposure start switch 7 (SW2) are depressed, the operations in steps 101, 102, and 103 are repeated. If the photometry/distance measurement start switch 6 (SW1) alone is depressed, operations in steps 103, 104, and 105 are repeated. Thereafter, AE (automatic exposure) and AF (automatic focus adjustment) calculations are performed (step 104). When the exposure start switch 7 (SW2) is depressed, an exposure operation on the film is performed. After the exposure operation is completed, the film is fed by one frame toward the cartridge (step 106). When the film is fed, the head 10 and the recording circuit 9 are operated, and the setting value information of the aspect ratio selected in step 101 is written in the track of the corresponding frame (step 107). Upon completion of the film feed operation for one frame, the flow advances to step 108 to detect the information set in step 102 so as to determine if it is selected that the aspect ratio is reset to the initial setting value for each frame (step 108). If the reset operation is selected, the aspect ratio is reset to the initial value set by the switch 14 ("H" if "H" is set by the switch 14) (step 109). In this case, since the setting value of the switch 14 is set in place of the information set in step 101, the display circuit 21 displays the setting value of the switch 14. Thereafter, the flow returns to step 103.
If it is determined in step 108 that the reset operation is not selected, the flow returns to step 103 without executing step 109. In this case, the information of the aspect ratio set in step 101 is kept set.
FIGS. 6A and 6B are flow charts showing an operation according to the second embodiment of the present invention. In this case, a camera has an arrangement shown in FIGS. 3 and 4. In FIGS. 6A and 6B, the ON/OFF state of the main switch 8 is detected (step 201). If the main switch 8 is ON, whether or not an auto-loading operation of a film need be performed, i.e., if the back lid is closed from an open state, and wherein the film is loaded is checked on the basis of the back lid open/close detect switch 11 and the patrone detect switch 19. If the back lid is closed, and the auto-loading operation need be performed, a film feed operation (pre-wind operation) is performed (step 203). During this operation, the regulated number of frames of the film is read by the film number reader 20 in step 204. One of shooting aspect ratios, i.e., the formats "H", "L", and "P" is selected (step 205). This operation is performed in the same manner as in step 101 in FIG. 5. Whether or not the aspect ratio is reset to the initial setting value for each frame is selected (step 206). This operation is performed in the same manner as in step 102 in FIG. 5. When the aspect ratio is reset to the initial setting value, the initial setting value is selected from "H", "L", and "P", and the selected value is set as D. This selection is made by detecting the setting value selected by the switch 14. It is then checked if the lens is changed (step 208). If the lens is changed, and if the reset operation is selected in step 206, i.e., it is selected that the aspect ratio is reset to the initial setting value, the information set in step 206 is detected in step 209, and it is determined that the reset operation is not prohibited. In step 210, the aspect ratio is reset to the value selected in step 207. Whether or not the lens is changed can be determined by detecting the ON/OFF state of the lens detect switch which is attached to a camera mount portion (not shown), and is turned on when a lens is mounted. When it is detected that the switch is turned off from an ON state, and is turned on again, it is determined that the lens is changed.
When the ON/OFF operation of the main switch is detected, if the main switch is OFF, it is checked if it is selected that the aspect ratio is reset to the initial setting value (step 211). If such selection is made, the aspect ratio is reset to the value selected in step 207 (step 212). At this time, assume that a routine from step 202 to step 210, when the main switch is ON, has already been executed.
The above-mentioned operation is executed when both the switches SW1 and SW2 are OFF.
When the photometry/distance measurement start switch 6 (SW1) alone is depressed, it is determined in step 213 that the switch 6 is ON, and AE and AF calculations are performed (step 214). Furthermore, when the exposure start switch 7 (SW2) is depressed, it is determined in step 215 that the switch 7 is ON, and an exposure operation on the film and a film feed operation for one frame after exposure are performed (step 216). The selected aspect ratio is written in the film (step 217) as in step 107 in FIG. 5. It is then checked if a shoot number has reached the regulated number read in step 204 (step 218). If the shoot number has reached the regulated number, the rewind operation is performed (step 219), and the control waits based on the state of the switch 11 until the back lid is opened (step 220) Thereafter, it is checked if it is selected that the aspect ratio is reset to the initial setting value (step 221). If such selection is made, the aspect ratio is reset to the value selected in step 207 (step 222), and the flow returns to step 213. However, if it is not selected that the aspect ratio is reset to the initial setting value, the flow returns to step 213 without resetting the aspect ratio.
In the above embodiment, the pre-wind type camera has been exemplified. The present invention can be similarly applied to a normal wind type camera, as a matter of course. | This invention relates to a camera for recording preset aspect ratio information on each shot frame.
In this invention, there is provided a camera of this type, which has a first mode for recording the preset aspect ratio information on frames in units of shooting operations, and a second mode for recording specific aspect ratio information regardless of the preset aspect ratio information on frames after the preset aspect ratio information is recorded on the shot frame, and can select one of the first and second modes. | 6 |
RELATED APPLICATIONS
This application is a divisional of application Ser. No. 09/365,014, filed Aug. 2, 1999, now U.S. Pat. No. 6,463,706, which is a divisional of application Ser. No. 08/929,885, filed Sep. 15, 1997, now U.S. Pat. No. 6,055,783, which two applications are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a fenestration unit which does not include an insulated glass unit (IGU). More specifically, the glass panes are placed directly into the sash without first being permanently fastened to each other by a spacer. This invention also includes a method for manufacturing a fenestration unit without the utilization of an IGU.
2. Description of the Prior Art
Early fenestration units, including windows and doors, only had a single pane of glass. Typically, the glass would be placed in the sash and then a glazing material would be applied to hold the glass into the sash. However, in more recent times, two or more panes of glass have been utilized in windows for better insulating value. A gap between any two glass panes creates further insulation. The prior art teaches the use of a separate spacer between the two glass panes to create such a gap and to structurally support the two panes of glass.
FIG. 1 illustrates a typical IGU 10 of the prior art. A first glass pane 11 is sealed to one end of spacer 12 with a sealant 14 , and a second glass pane 16 is sealed to the other end of spacer 12 with sealant 14 . The spacer 12 can be of many different shapes but often it is made with a jagged edge as shown in FIG. 1 to reduce the conductance of heat through the spacer. This combination of two or more glass panes separated by a spacer is manufactured as a unit (IGU 10 ) and then later placed into the sash of the fenestration unit.
FIG. 2 illustrates the IGU 10 after it has been placed in the sash 17 of a fenestration unit.
The prior art fenestration units have a number of problems. Manufacturing involves two operations in which the first operation is manufacturing the IGU and the second operation is placing the IGU in the sash. This dual operation process incorporates significant cost into the fenestration unit. Additionally, this dual operation process typically involves shipping glass from the glass factory to the window manufacturer in the form of an IGU. Such shipping involves greater cost because the IGU's take up more space and they are easier to break than individual glass panes. Additionally, despite efforts to minimize thermal conductivity through the spacer 12 , there continues to be significant heat loss through the spacer 12 .
SUMMARY OF THE INVENTION
The invention has as its object manufacturing a fenestration unit in one operation wherein the glass panes are placed directly into the sash without the first operation of manufacturing an IGU. The sash (also referred to as the “support structure”) of the fenestration unit of this invention provides all of the structural support for the glass panes without the use of an IGU. In other words, the support of the glass panes is an integral part of the sash.
The invention provides a method of manufacturing a fenestration unit including the steps of constructing a support structure including a first receiving surface and a second receiving surface, placing a vapor barrier in contact with the first receiving surface and in contact with the second receiving surface, depositing a first primary sealant on a portion of the vapor barrier in contact with the first receiving surface, depositing a second primary sealant on a portion of the vapor barrier in contact with the second receiving surface, placing a first glass pane onto the first primary sealant on the first receiving surface, placing a second glass pane onto the second primary sealant on the second receiving surface, depositing a first secondary sealant between the first glass pane and the first receiving surface, where the first glass pane is structurally supported by the first receiving surface, and depositing a second secondary sealant between the second glass pane and the second receiving surface, where the second glass pane is structurally supported by the second receiving surface.
The invention also includes a fenestration unit comprising a first glass pane and a second glass pane. Both glass panes have an inside surface and an outside surface such that the inside surfaces face each other. The fenestration unit also includes a support structure having a first receiving surface and a second receiving surface. The first receiving surface of the sash receives the inside and outside surfaces of the first glass pane and the second receiving surface receives the inside and the outside surfaces of the second glass pane. The fenestration unit also includes a vapor barrier placed in contact with the first receiving surface and the second receiving surface.
The invention further provides a method of manufacturing a fenestration unit including the steps of constructing support structure members where each support structure member has a first receiving surface, a second receiving surface, a first end, and a second end. The method also includes the steps of depositing a first secondary sealant on the first receiving surfaces of each of the support structure members, depositing a second secondary sealant on the second receiving surfaces of each of the plurality of support structure members, positioning first and second glass panes on the first and second receiving surfaces, respectively, and fastening the ends of the support structure members to each other. This method forms a support structure around the first and second glass panes where the first receiving surface contacts the inside surface of the first glass pane and the second receiving surface contacts the inside surface of the second glass pane.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a prior art IGU.
FIG. 2 is a cross-sectional view of an IGU of the prior art inserted into a sash.
FIG. 3 is a frontal view of the fenestration unit of the invention including a partial cut-away.
FIG. 4 is a cross-sectional view of a first embodiment of the invention taken along the lines 4 — 4 of FIG. 3 .
FIG. 5 is a cross sectional view of the anti-outgassing strip of the first embodiment.
FIG. 6 is a cross-sectional view of the first embodiment of the invention and a window frame in a casement application.
FIG. 7 is a frontal view of the fenestration unit of a second embodiment of the invention including a partial cut-away.
FIG. 8 is a cross-sectional view of the second embodiment of the invention taken along a line 8 — 8 of FIG. 3 .
FIG. 9 is a cross-sectional view of the anti-outgassing strip of the second embodiment.
FIG. 10 is a cross-sectional exploded view of a third embodiment of the invention.
FIG. 11 is a frontal view of the fenestration unit of a fourth embodiment of the invention.
FIG. 12 is a cross-sectional view of a fourth embodiment of the invention taken along the line 12 — 12 of FIG. 11 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
FIG. 3 generally illustrates a fenestration unit 18 of the invention. The fenestration unit 18 includes a sash 19 which could also be a window or door frame. The use of the term “sash” is not intended to be limited to a strict sense of the word, but instead is defined as any structure that supports or holds a transparent material such as a glass pane. Therefore, the term “sash” will be used throughout this detailed description of the preferred embodiments, but it is understood to include a typical sash as well as any suitable support structure. The sash 19 includes four sash members 19 a , 19 b , 19 c and 19 d and is rectangular in shape. However, the sash members do not have to be lineal and the sash 19 could be any shape. Construction of the sash 19 involves constructing the sash members 19 a-d and then fastening the sash members 19 a-d together to create the sash 19 . The sash members 19 a-d can be constructed by extrusion, wood milling or any other suitable manufacturing technique. The four sash members 19 a-d can be fastened together in any manner known in the art. For example, depending on the type of material used for the sash 19 , the lineal sash members 19 a-d could be connected together by an additional piece of connecting hardware, by vibratory welding, by temporary insertion of a heat plate between two adjacent sash members, or by any other method known in the art.
The sash 19 supports the first glass pane 20 and second glass pane 21 . The first glass pane 20 has an inner portion 22 and a border portion 23 (as seen through the cutaway portion of the sash 19 ). The border portion 23 is the portion around the periphery of the first glass pane 20 , i.e., the portion proximate to the sash 19 . In a preferred embodiment, the border portion 23 extends from the side 30 of the first glass pane 20 to about one inch from the side 30 in the direction of the interior portion 22 of the first glass pane 20 . The inner portion 22 is the portion of the first glass pane 20 which is not part of the border portion 23 and which is therefore a further distance from the sash 19 . The second glass pane 21 also has an inner portion 24 and a border portion 25 (also shown in the cut-away portion of the sash 19 ). The inner portion 24 and the border portion 25 are defined the same as above for the first glass pane 20 . The outside surface 26 of the first glass pane 20 faces the outdoors. The outside surface 32 of the second glass pane 21 faces the indoors.
FIG. 4 is a cross-sectional view of the first embodiment of the invention taken along the lines 4 — 4 of FIG. 3 . The first glass pane 20 includes an outside surface 26 , an inside surface 28 and a side 30 . The second glass pane 21 includes an outside surface 32 , an inside surface 34 and a side 36 .
The sash 19 may be made of any low-thermally conducting material. For example, the sash 19 could be hollow vinyl, hollow thermoplastic, thermoset pultrusion, milled solid wood or wood with a vinyl coating. Alternatively, the sash could be made of Fibrex™ material which is a wood fiber and polyvinyl chloride(PVC) composite patented by Andersen Corporation (See U.S. Pat. Nos. 5,406,768; 5,497,594; 5,441,801; 5,518,677; 5,486,553; 5,539,027).
The sash 19 includes a first receiving surface 38 , a second receiving surface 40 and an interior surface 42 . An anti-outgassing strip 44 has a first leg 47 at one end of the anti-outgassing strip 44 and a second leg 49 at the opposite end and an interior portion 53 . The interior portion 53 is located between the first leg 47 and the second leg 49 . The first leg 47 is attached to the first receiving surface 38 , the second leg 49 is attached to the second receiving surface 40 and the interior portion 53 of the anti-outgassing strip 44 is attached to the interior surface 42 of the sash 19 . The strip 44 is illustrated in FIGS. 4 and 5 . The anti-outgassing strip 44 prevents gas particles in the sash 19 from outgassing into the space 45 between the first glass pane 20 and the second glass pane 21 , where these particles could interfere with the clarity of the fenestration unit 18 . The anti-outgassing strip 44 is a thin foil of metal but could be any material that prevents the gas particles from the sash 19 from passing through to the space 45 . For example, the anti-outgassing strip 44 may be made of stainless steel or aluminum. The anti-outgassing strip 44 is preferably made as thin as possible to reduce the conduction of heat through the strip 44 and yet thick enough to prevent outgassing. A stainless steel anti-outgassing strip 44 must be at least about 0.001″ (inches) thick in order to effectively reduce the movement of gas particles from the sash 19 to the space 45 . It is sometimes desired to use an anti-outgassing strip 44 that is between about 0.003″ (inches) and 0.005″ (inches) because such a thickness is easier to apply to the sash 19 without tearing or destroying the anti-outgassing strip 44 . It is also within the scope of this invention to apply a metallic spray to the interior surface 42 , the first receiving surface 38 and the second receiving surface 40 . This metallic spray would then be an anti-outgassing strip. The anti-outgassing strip 44 may be affixed to the sash 19 by an adhesive. Alternatively, the anti-outgassing strip 44 may include barbs 43 , as shown in FIGS. 4 and 5 , which are pressed into the sash and which hold the anti-outgassing strip 44 to the sash 19 . It is also within the scope of this invention to merely place an anti-outgassing strip, without barbs and without an adhesive, on the interior surface 42 , the first receiving surface 38 and the second receiving surface 40 . Then the sealants and glass panes are placed as shown in FIG. 4 and described below to permanently hold the strip 44 in place.
The various sealants and their functions will now be described. The portion of the outside surface 26 of the border portion 23 of the first glass pane 20 that is not situated over the anti-outgassing strip 44 is attached to the first receiving surface 38 by a first secondary sealant 46 . The function of the first secondary sealant 46 is to provide an adhesive bond between the first glass pane 20 and the sash 19 . This adhesive bond is structural and prevents the first glass pane 20 from breaking away from the sash 19 in strong winds. The first secondary sealant 46 also prevents water from flowing along the outside surface 26 of the first glass pane 20 and into the space 45 . GE 2512 by General Electric Company is used as first secondary sealant 46 but other adhesives known in the art for attaching glass to the sash material may also be used. The portion of the outside surface 26 of the border portion 23 that is situated over the anti-outgassing strip 44 is attached to the anti-outgassing strip 44 by a first primary sealant 48 . The function of the first primary sealant 48 is to prevent migration of air or argon or any other insulating gas from the space 45 to the world outside the space 45 . The first primary sealant 48 could be any compound that prevents such migration such as, for example, polyisobutylene. The function of the sealant 48 is to prevent gas molecules from moving either into the space 45 or from leaving the space 45 . It is within the scope of this invention to use one adhesive/sealant in place of first secondary sealant 46 and first primary sealant 48 . The single adhesive would perform a dual function of structurally supporting the glass panes and sealing the space 45 .
The portion of the inside surface 34 of the border portion 25 of the second glass pane 21 that is not situated over the anti-outgassing strip 44 is attached to the second receiving surface 40 by a second secondary sealant 50 which is the same as and performs substantially the same function as the first secondary sealant 46 . The portion of the inside surface 32 of the border portion 25 of the second glass pane 21 that is situated over the anti-outgassing strip 44 is attached to the anti-outgassing strip 44 by a second primary sealant 52 . The second primary sealant 52 is the same as and performs substantially the same function as the first primary sealant 48 .
The depositing of the secondary sealants 46 and 50 and the primary sealants 48 and 52 may be accomplished by hand or using a machine. For example, a caulk gun could be used to deposit the various sealants. Robotic machines are also known in the art for depositing sealants in a specified pattern.
The first receiving surface 38 may include a lip 54 which is a portion that is raised from the remainder of the first receiving surface 38 . The lip 54 provides a space between the first glass pane 20 and the first receiving surface 38 such that the first secondary sealant 46 and the first primary sealant 48 are not squeezed out from between the first glass pane 20 and the first receiving surface 38 , thereby preventing a messy appearance along the interface between the sash 19 and the inner portion 22 of the outside surface 26 of the first glass pane 20 .
The sash shown in FIG. 4 defines hollowed portions 56 which allow for a lighter weight sash 19 while retaining structural integrity and excellent insulating properties. However, the invention is not limited to this configuration. A sash defining more or fewer hollowed portions or no hollowed portions or differently shaped hollowed portions would also be within the scope of the invention. For example, if the sash 19 was made of milled wood, then it would not include the hollowed portions 56 .
The sash 19 includes a flange 58 adjacent to the side 36 of the second glass pane 21 . The flange 58 provides guidance to the proper placement of the second glass pane 21 . There is a gap 57 between the end 36 of the second glass pane 21 and the flange 58 . The purpose of the gap 57 is to allow the thermal expansion and contraction of the second glass pane 21 and to allow for permanent shrinkage of the sash 19 .
The second receiving surface 40 includes a stop 41 which is a portion of the sash which is raised. The stop 41 creates a gap between the second glass pane 21 and the second receiving surface 40 such that the second secondary sealant 50 and the second primary sealant 52 can remain in that gap. The stop 41 is located at the end of the anti-outgassing strip 44 and the stop 41 therefore forms the juncture between the second secondary sealant 50 and the second primary sealant 52
A desiccant material 60 may be attached to the anti-outgassing strip 44 by an adhesive. In the preferred embodiment, the dessicant 60 is an extruded, hot melt adhesive. The desiccant material 60 assists in the removal of moisture from the space 45 . The dessicant material 60 could alternatively be an adhesive type dessicant as described in U.S. Pat. Nos. 5,510,416; 5,509,984; and 5,503,884 owned by H. B. Fuller Licensing & Financing, Inc.
The space 45 contains a thermally insulating gas. For example, air, Argon or Krypton or some combination of these three gases could be used. If air is used, then the manufacture of the fenestration unit 18 is simplified, because the dessicant 60 will remove moisture from the space 45 and no steps are necessary to remove the air and replace it with another gas. The description below discusses filling the space 45 with Argon as an example. The description also applies to other gases that may be used.
Filling the space 45 with Argon involves the following steps. First, the sash 19 is constructed with a hole or multiple holes that connect the space 45 to the outside air. An example hole is shown as hole 61 . A hose can be inserted into this hole and the air sucked out of the space 45 through the hose. Then Argon can be inserted into the space 45 through the same hose that passes through hole 61 . Alternatively, one or more holes 61 may be used to remove the air while Argon is inserted into the space 45 through one or more other holes also similar to hole 61 . Other methods of inserting Argon into the space 45 may be used. Once the space 45 is filled with Argon, then the plug 59 , shown in exploded view for clarity, is inserted in the hole 61 to seal the space 45 . There could be multiple holes 61 and plugs 59 per sash 19 . The plug 59 can be maintained in the hole 61 by any method including a friction fit or use of an adhesive.
The second secondary sealant 50 and the second primary sealant 52 may be visible through the second glass pane 21 . Therefore, it may be desirable to place a decorative trim piece along the border portion of the second glass pane 21 to hide the sealants from view.
The manufacture of the embodiment shown in FIG. 4 will now be described. First, the sash 19 including the first receiving surface 38 and the second receiving surface 40 is constructed. The construction of the sash 19 includes joining the members 19 a-d . Next, the anti-outgassing strip is placed on the interior surface 42 , a portion of the first receiving surface 38 and a portion of the second receiving surface 40 . As discussed above, the anti-outgassing strip 44 may be attached to the sash 19 by barbs or by an adhesive. A dessicant as described above is then attached to the portion of the anti-outgassing strip 44 that is adjacent to the interior surface 42 of the sash 19 . The first secondary sealant 46 is deposited on the portion of the first receiving surface 38 that is not in contact with the anti-outgassing strip 44 . The second secondary sealant 50 is deposited on the portion of the second receiving surface 40 that is not in contact with the anti-outgassing strip 44 . Next, the first primary sealant 48 is deposited on the first leg 47 of the anti-outgassing strip 44 . The second primary sealant 52 is deposited on the second leg 49 of the anti-outgassing strip 44 . The next step is to place the border portion 23 of the outside surface 26 of the first glass pane 20 onto the first receiving surface 38 such that the border portion 23 of the outside surface 26 of the first glass pane 20 sits on the first secondary sealant 46 and the first primary sealant 48 . There should be a gap between the end 30 and the interior surface 42 of the sash 19 . Next, the border portion 25 of the inside surface 34 of the second glass pane 21 is placed on the second receiving surface 40 such that the border portion 25 of the inside surface 34 of the second glass pane 21 sits on the second secondary sealant 50 and the second primary sealant 52 . There should be a gap 57 between the end 36 and the flange 58 . Finally, the space 45 is filled with a thermally insulating gas through the hole 61 as described above.
FIG. 6 is similar to FIG. 4 with the addition of a frame 62 that would be used for a casement window. The outside surface 26 of the first glass pane 20 faces the outdoors. The outside surface 32 of the second glass pane 21 faces the indoors.
In FIG. 6 , the plug 59 is shown inserted into the sash assembly. A flexible bulbed weatherstop 63 is attached to the frame 62 . When the casement window is in a closed position as shown in FIG. 6 , the flexible bulbed weatherstop 63 is in contact with the outside surface 32 of the second glass pane 21 . The sash 19 may be rotated outward away from the frame 62 as is typical of a casement window. In such a case, the outside surface 32 of the second glass pane 21 moves away from the flexible bulbed weatherstop 63 . The purpose of the flexible bulbed weatherstop 63 is to seal the window to prevent water from traveling between the frame 62 and the sash 19 when the window is in its closed position.
The manufacture of the structure shown in FIG. 6 is the same as for the structure shown in FIG. 4 with the additional step of placing the flexible bulbed weatherstop 63 into a groove 77 in the frame 62 . The weatherstop 63 is friction fit into the groove 77 so that the weatherstop 63 will not fall out of the groove 77 . Alternatively, an adhesive could be placed in the groove 77 to more securely fasten the weatherstop 63 in the groove. The groove 77 is located such that weatherstop 63 is adjacent the second glass pane 21 when the window is in the closed position as shown in FIG. 6 .
A frontal view of the second embodiment of the invention is shown in FIG. 7 . The sash 76 is made of four sash members 76 a-d . Each sash member has two ends, for example end 100 and end 102 of sash member 76 a . The first glass pane 64 has an inner portion 65 and a border portion 67 . The second glass pane 70 has an inner portion 71 and a border portion 73 . The inner and border portions in this embodiment are defined the same as with respect to the previous embodiment described above.
FIG. 8 is a cross-sectional view taken along the lines 8 — 8 in FIG. 7 . Again, in this embodiment as in the first embodiment discussed above, there is not a separate spacer between the two panes of glass and the glass panes are structurally supported entirely by the sash 76 .
The first glass pane 64 has an inside surface 66 , an outside surface 68 and a side 69 . The second glass pane 70 has an outside surface 72 , an inside surface 74 and a side 75 . The inside surface 66 of the first glass pane 64 faces the inside surface 74 of the second glass pane 70 .
The sash 76 includes a channel having a U-shaped cross-section and a plurality of receiving surfaces 78 that receive the border portion 67 of the inside surface 66 of the first glass pane 64 , and the border portion 67 of the outside surface 68 of the first glass pane 64 . The channel's receiving surface 78 may also abut against the side 69 of the first glass pane 64 .
Moreover, the sash 76 includes a second channel having receiving surfaces 80 that receive the border portion 73 of the inside surface 74 of the second glass pane 70 , and the border portion 73 of the outside surface 72 of the second glass pane 70 . The second channel's receiving surface 80 may also abut against the side 75 of the second glass pane 70 .
The sash 76 also includes an interior surface 81 which extends between the first and second channels. In this embodiment, the anti-outgassing strip 82 has a U-shaped cross-section, with an interior portion extending between a first leg 97 and a second leg 98 . The central portion of the anti-outgassing strip 82 extends across the sash's interior surface 81 . Each leg of the strip 82 abuts against the first receiving surface 78 into the second receiving surface 80 . The anti-outgassing strip 82 is made of the same material and performs the same function as the anti-outgassing strip 44 of the first embodiment shown in FIG. 4 . The anti-outgassing strip 82 may be attached to the sash 76 by an adhesive or by barbs 79 . FIG. 9 shows a cross section of the anti-outgassing strip 82 including barbs 79 which are inserted into the sash 76 .
The first receiving surface 78 is attached to the border portion 67 of the outside surface 68 of the first glass pane 64 by a adhesive 84 . The second receiving surface 80 is attached to the border portion 73 of the outside surface 72 of the second glass pane 70 by a adhesive 85 . The adhesives 84 and 85 are the same and perform the same function as the adhesives 46 and 50 of the first embodiment.
The anti-outgassing strip 82 is attached to the border portion 67 of the inside surface 66 of the first glass pane 62 by a sealant 86 . The anti-outgassing strip 82 is attached to the border portion 73 of the inside surface 74 of the second glass pane 70 by a sealant 88 . The sealants 86 and 88 are the same and perform the same function as the sealants 48 and 52 of the first embodiment.
The receiving surfaces 78 and 80 may contain stops 89 and 91 respectively, for allowing some space for the sealant 86 (i.e. first primary sealant 86 ) and the sealant 88 (i.e. second primary sealant 88 ) between the inside surfaces 66 and 74 and the receiving surfaces 78 and 80 , respectively. The stops 89 and 91 are raised portions that rise above the remainder of the receiving surfaces. The purpose of the stops 89 and 91 is to prevent the first and second primary sealants 86 and 88 from squeezing out from between the receiving surfaces 78 and 80 and the first and second glass panes 64 and 70 respectively. The receiving surfaces 78 and 80 may be designed without the stops 89 and 91 but then some squeeze out of the primary sealants may occur.
The portions of the receiving surfaces 78 and 80 adjacent to the outside surfaces 68 and 72 of the first and second glass panes 64 and 72 respectively, are angled away from the glass so that the distance from the glass to the sash becomes less, nearer to the edges 69 and 75 . The purpose of this angle in the receiving surfaces of the sash is to facilitate the deposition of a first secondary sealant 84 and a second secondary sealant 85 between the sash and the first and second glass panes 64 and 70 respectively. It should be noted however that the present invention is not limited to the described receiving surfaces. The receiving surfaces described above are a preferred embodiment.
In a preferred embodiment the first receiving surface 78 also includes a raised member 93 for applying pressure to the outside surface 68 of the first glass pane 64 to hold the inside surface 66 of the first glass pane 64 in contact with the stop 89 . Additionally the second receiving surface 80 includes a raised member 95 for applying pressure to the outside surface 72 of the second glass pane 70 to hold the inside surface 74 in contact with the stop 91 .
The raised members 93 and 95 can be any shape which applies the appropriate pressure and should be flexible enough to allow the first secondary sealant 84 and second secondary sealant 85 to pass between it and the adjacent glass pane when such sealants are deposited. In a preferred embodiment the raised member 93 and 95 are rigid PVC.
FIG. 8 also shows the desiccant material 90 attached to the anti-outgassing strip 82 along the interior surface 81 of the sash 76 . The purpose and design of the desiccant material 90 is the same as the purpose and design of the desiccant material 60 in the first embodiment of the invention. A dessicant adhesive as described above with respect to the first embodiment may also be used for this embodiment.
Again, with this embodiment as in the first embodiment, either air or Argon or a combination of both may be used to fill the space 92 between the first glass pane 64 and the second glass pane 70 . If Argon is used, then a hole 94 may be used to insert a hose for removing air and inserting Argon into the space 92 . Once the space 92 is filled or partially filled with Argon, then it may be blocked with a plug 96 which is shown in exploded view for clarity.
The manufacture of the second embodiment involves the following steps. First, the sash members 76 a-d are constructed. The sash members can be made from an extruded vinyl or composite or other material, or they can be milled from a wood. Second, the anti-outgassing strip 82 is placed on the interior surface 81 of the sash members 76 a-d . The placement of the anti-outgassing strip 82 can either utilize an adhesive or barbs or both. In a preferred embodiment the anti-outgassing strip 82 has a first leg 97 , a second leg 98 and an interior portion 99 , wherein the interior portion 99 is between the first leg 97 and the second leg 98 . The first leg 97 is adjacent to a portion of the first receiving surface 78 , the second leg is adjacent to a portion of the second receiving surface 80 and the interior surface 99 of the anti-outgassing strip 82 is adjacent to the interior surface 81 of the sash 76 .
The first secondary sealant 84 is deposited on the portion of the first receiving surface that is not in contact with the anti-outgassing strip 82 . The first primary sealant 86 is deposited on the first leg 97 of the anti-outgassing strip 82 . The second secondary sealant 85 is deposited on the portion of the second receiving surface 80 that is not in contact with the anti-outgassing strip 82 . The second primary sealant 88 is deposited on the second leg 98 of the anti-outgassing strip 82 . The depositions can be done manually using a caulk gun or automatically with a machine or robot. Then the first glass pane 64 is placed on a platform or support and the second glass pane 70 is suspended parallel and above the first glass pane 64 with the space between the two glass panes being similar or equal to the space 92 desired in the ultimate fenestration unit. For example, suction cups could be applied to the outside surface 72 of the second glass pane 70 to suspend the second glass pane 70 over the first glass pane 64 . The sash members 76 a-d are then placed around the first and second glass panes 64 , 70 such that the first receiving surface 78 receives the border portion of the first glass pane 64 and the second receiving surface 80 receives the border portion of the second glass pane 70 . The ends of the sash members 76 a-d are then fastened together using heat plates or vibratory welding or any other means of fastening the ends of sash members 76 a-d together to form a sash 76 . The resulting sash 76 as shown is rectangular in shape, but it could be any shape.
A third embodiment of the invention is shown in exploded view in FIG. 10 . This embodiment is similar to the second embodiment shown in FIG. 8 with the difference being that the sash in the third embodiment is three sash sections 110 , 112 and 114 . When the parts are assembled together the first receiving surface 120 of the first sash section 110 is adjacent to the outside surface 68 and a portion of the end 69 . The second receiving surface 122 of the second sash section 112 is adjacent to the inside surface 66 and a portion of the end 69 . The third receiving surface 124 located on the second sash section 112 is adjacent to the inside surface 74 and a portion of the end 75 . The fourth receiving surface 126 of the third sash section 114 is adjacent to a portion of the end 75 and the outside surface 72 .
If the sash is rectangular, then there are four first sash sections, four second sash sections and four third sash sections. The advantage of using first, second and third sash sections 110 , 112 and 114 is that manufacturing is accomplished in a bed formation in which one layer is placed on top of the other. The manufacturing steps are described below.
First, the three sash sections 110 , 112 and 114 are assembled. For a rectangular window, this assembly comprises connecting the four first sash section lineals to each other at the corners to form a rectangular frame. The connection can be by any of the methods described above including hot plate welding, vibratory welding or the use of a mechanical fastener. This rectangular frame is referred to in whole as the first sash section 110 . The same assembly process is performed to assemble the second and third sash sections 112 and 114 . Next, the anti-outgassing strip 82 is placed on the interior surface 81 , on the second receiving surface 122 and on the third receiving surface 124 . Then the dessicant material 90 is placed on the interior surface 81 of the second sash section 112 .
A first secondary sealant 84 is deposited on the first receiving surface 120 . Alternatively, the first secondary sealant 84 can be deposited on the border portion 67 of the outside surface 68 of the first glass pane 64 . Then the border portion 67 of the outside surface 68 of the first glass pane 64 is placed on the first receiving surface 120 . A first primary sealant 86 is deposited on the portion of the anti-outgassing strip 82 that is adjacent to the second receiving surface 122 . Alternatively, the first primary sealant 86 can be deposited on the border portion 73 of the inside surface 66 of the first glass pane 64 . Next, the second sash section 112 is lowered onto the first sash section such that the portion of the anti-outgassing strip 82 that is adjacent to the second receiving surface 122 is placed on the border portion 73 of the inside surface 66 of the first glass pane 64 . A second primary sealant 88 is deposited on the portion of the anti-outgassing strip 82 that is adjacent to the third receiving surface 124 . Alternatively, the second primary sealant 88 may be deposited on the border portion 73 of the inside surface 74 of the second glass pane 70 . Then the border portion 73 of the inside surface 74 is placed on the portion of the anti-outgassing strip 82 adjacent to the third receiving surface 124 . A second secondary sealant 85 is deposited on the fourth receiving surface 126 . Alternatively, the second secondary sealant 85 may be deposited on the border portion 73 of the outside surface 72 . The fourth receiving surface 126 is then placed on the border portion 73 of the outside surface 72 .
The three sash sections 110 , 112 and 114 may be connected together by any method including by an adhesive such as silicone sealant or by use of a fastener. FIG. 10 shows a screw 130 which fits into the hole 132 which extends through the third and second sash sections 114 and 112 and partially into the first sash section 110 . A number of such screws 130 would be inserted into a corresponding number of holes 132 around the entire sash to connect all three sash sections together. The end result is that the three sash sections 110 , 112 and 114 are connected to form one sash which supports the glass panes.
A fourth embodiment of the invention is shown in FIGS. 11-12 . FIG. 11 generally illustrates a fenestration unit 170 of the invention. The fenestration unit 170 includes a sash 200 which could also be a window or door frame. The sash 200 includes four sash members 200 a , 200 b , 200 c and 200 d and is rectangular in shape. However, the sash members do not have to be lineal and the sash 200 could be any shape. Construction of the sash 200 involves constructing the sash members 200 a-d and then fastening the sash members 200 a-d together to create the sash 200 . The sash members 200 a-d can be constructed by extrusion, wood milling or any other suitable manufacturing technique. The four sash members 200 a-d can be fastened together in any manner known in the art. For example, depending on the type of material used for the sash 200 , the lineal sash members 200 a-d could be connected together by an additional piece of connecting hardware, by vibratory welding, by temporary insertion of a heat plate between two adjacent sash members, or by any other method known in the art.
The sash 200 supports the first glass pane 222 and second glass pane 230 creating a space 181 between the glass panes. The first glass pane 222 has an inner portion 172 and a border portion 174 . The inner portion 172 and the border portion 174 are defined the same as for the prior embodiments. In a preferred embodiment, the border portion 174 (seen through the cut-away of the upper glazing bead 175 ) extends from the side 176 of the first glass pane 222 to about one inch from the side 176 in the direction of the inner portion 172 of the first glass pane 222 . The second glass pane 230 also has an inner portion 178 and a border portion 180 . The inner portion 178 and the border portion 180 are defined the same as above for the first glass pane 222 .
FIG. 12 shows a cross sectional view of the fourth embodiment of the invention. The sash 200 is the same material and is constructed in the same manner as the sash 19 described above. The sash 200 has a hollowed portion 182 . This hollowed portion is to reduce the weight of the fenestration unit 170 . However, the invention is not limited to the particular shape of the hollowed portion 182 shown in FIG. 12 and in fact it is within the scope of this invention to use a solid sash 200 without a hollow portion 182 . The sash includes a first receiving surface 202 which is generally flat but including a stop 204 which is portion of the first receiving surface that is raised above the generally flat portion of the first receiving surface 202 . The sash 200 also includes a second receiving surface 206 which is generally flat but includes a stop 208 . The sash 200 also includes an interior surface 210 which is located between the first receiving surface 202 and the second receiving surface 206 .
An anti-outgassing strip 212 which is the same as the anti-outgassing strip 82 is located in contact with the interior surface 210 . The anti-outgassing strip includes barbs 213 for attaching to the sash 200 . However, as described above, the invention is not limited to the use of barbs for attachment to the sash 200 . The anti-outgassing strip 212 includes a first leg 214 , a second leg 216 and an interior portion 218 . The first leg 214 is in contact with a portion of the first receiving surface 202 as shown in FIG. 12 . The second leg 216 is in contact with a portion of the second receiving surface 206 also as shown in FIG. 12 . The first leg 214 and the second leg 216 extend up to the respective stops 204 and 208 . The interior portion 218 is in contact with the interior surface 210 of the sash 200 . The purpose of this anti-outgassing strip 212 is the same as for the first two embodiments of this invention.
A dessicant material 184 is located on the interior surface 218 of the anti-outgassing strip 212 . A plug 186 is shown exploded out from the hole 188 . The plug 186 fits into the hole 188 and serves the same purpose as the plugs and holes in the earlier described embodiments.
A first secondary sealant 220 is located between the inside surface 221 of the first glass pane 222 and the first receiving surface 202 . The first secondary sealant 220 is the same as the first secondary sealant discussed above with respect to the first two embodiments of this invention. A first primary sealant 224 is located between the first leg 214 of the anti-outgassing strip 212 and the first glass pane 222 . The first primary sealant 224 is the same as the first primary sealants in the first two embodiments of this invention.
A second secondary sealant 226 is located between the inside surface 228 of the second glass pane 230 and the second receiving surface 206 . The second secondary sealant 226 is the same as the first secondary sealant 220 . A second primary sealant 232 is located between the second leg 216 of the anti-outgassing strip 212 and the second glass pane 230 . The second primary sealant 232 is the same as the first primary sealant 224 . The stops 204 and 208 serve the same function as the stop 41 in the first embodiment.
The upper glazing bead 175 is an aesthetic piece which hides the second secondary sealant 226 and the second primary sealant 232 from view of an observer. Likewise, the lower glazing bead 177 hides the first secondary sealant 220 and the first primary sealant 224 from view of an observer. The tips 190 and 192 of the glazing beads 177 and 175 are flexible so that the tips can be pressed tightly against the outside surfaces of the glass panes. The glazing beads 177 and 175 may also apply some pressure to the outside surfaces of the first and second glass panes 222 and 230 respectively. This pressure may assist in holding the glass panes in place while the sealants 220 , 224 , 226 and 232 are curing.
The manufacturing steps in this fourth embodiment are the same as for the first embodiment with one exception. The first glass pane is positioned on the sash 200 differently in that the border portion 174 of the inside surface 221 of the first glass pane 222 is placed on the first receiving surface 202 . The first glass pane 222 may be placed on a support structure to hold the first glass pane in contact with the sealants and the first receiving surface. Such a support could be a table or other structure. Alternatively, a fast curing sealant or hot melt can be used as the first secondary sealant 220 to allow the first glass pane 222 to be quickly adhered to the first receiving surface 202 .
The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. | A multi-paned fenestration unit in which the glass panes are manufactured directly into the support structure without first manufacturing an insulated glass unit. The support structure is designed to provide the structural support for the glass panes without a separate spacer. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to French Application No. 1050433 filed Jan. 22, 2010, which application is incorporated herein by reference and made a part hereof.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates in particular to a detection method for a motor vehicle.
[0004] 2. Description of the Related Art
[0005] In the field of driving assistance, a plurality of functions have arisen. These require as sensors cameras which can analyze the scene, and these functions thus provide assistance in making a decision, or permit automation of certain tasks which had hitherto been the responsibility of the driver of the vehicle.
[0006] Reference can be made for example, non-exhaustively, to the automation of the high-beam/low-beam function, parking assistance functions, adaptive lighting functions, and detection of lines on the ground.
[0007] In these different cases, and for each application, the field of vision of the camera is adapted to the situation.
[0008] However, in view of the increasing concern for reduction of costs, and for standardization, motor vehicle manufacturers would like the sensors to be in common. This multi-functionality involves compromises in terms of the field of vision. The field of vision selected is the best compromise between the needs of each application.
[0009] This compromise may not eliminate all the contradictions, and some functions are then downgraded in terms of performance.
[0010] In addition, the solution to some functions has now been found in the form of use of specific sensors (for example: the front side view application provided by a front corner camera).
[0011] Also in a concern for reduction of the costs, it is advantageous to propose solutions for this type of application which would use existing sensors, i.e., which already carry out other functions in the vehicle.
[0012] Finally, some functions still do not have technical solutions, or have weaknesses which can be improved.
[0013] A headlight which is fitted such as to rotate around a vertical axis is also known from patent FR 2 899 967, which is equivalent to U.S. Pat. No. 7,595,634, which is incorporated herein by reference and made a part hereof.
[0014] What is needed, therefore, is an improved system and method for detection which improves driving of the vehicle.
SUMMARY OF THE INVENTION
[0015] One object of the present invention is in particular to respond to the various above-described needs, for example, by putting several items of equipment of the vehicle in common.
[0016] Another object of the invention is in particular a detection method for a motor vehicle, this method using at least one camera which has a field of vision, this method comprising the following steps:
receiving information which is representative of a driving state associated with the vehicle; and modifying, preferably automatically, a field of vision of the camera, and in particular its orientation, according to the information.
[0019] The field of vision of the camera can be formed by a solid angle (or cone of perception) defined by the orientation of an optical axis of the camera and its viewing angle.
[0020] The field of vision defines in particular the target space of the camera, i.e., the area of perception of the camera.
[0021] A base of the solid angle can be for example rectangular.
[0022] According to an embodiment of the invention, information which is representative of a driving state associated with the vehicle is selected from amongst: vehicle cornering information, information on the type of environment of the vehicle (this type of environment being able to be for example urban, i.e., the vehicle is in a town, or rural, i.e., the vehicle is in the countryside), information about conditions of climate or brightness, or information about control of a flashing light of the vehicle.
[0023] If applicable, the information which is representative of a driving state associated with the vehicle is cornering information about the vehicle, selected from an angle on the vehicle steering wheel, or location data of the vehicle, such as GPS data.
[0024] Advantageously, the vehicle comprises a headlight which can emit a light beam, the orientation of which can be modified in order to follow a bend, and the orientation of the field of vision of the camera is modified according to the modification of the orientation of the beam of the headlight when at a bend.
[0025] If required, the camera is mobile simultaneously with displacement of the headlight, this displacement comprising, for example, of pivoting.
[0026] The headlight can be associated with a DBL device, in order to displace the beam at a bend, and the camera can be associated with the DBL device, whilst, for example, being fitted on this DBL device, or being physically connected to this DBL device.
[0027] According to an embodiment of the invention, the camera is fitted on an independent platform of the vehicle headlights, this platform being designed to permit movement of the camera relative to the vehicle. This platform is, for example, secured to the vehicle windscreen.
[0028] If applicable the information which is representative of a driving state associated with the vehicle is information about the speed of the vehicle, or information about the brightness of the environment.
[0029] Advantageously, the field of vision of the camera is modified, in particular its orientation, when the speed of the vehicle is below a predetermined threshold, in particular in order to widen visibility on one side of the road at least.
[0030] For example, at least two cameras are provided, and, when the speed of the vehicle is below a predetermined threshold, the orientation of the cameras is modified so that the respective fields of vision move apart from one another in order to widen visibility on both sides of the vehicle.
[0031] If applicable, the field of vision of the camera is modified when the vehicle location information indicates the presence of a complex urban environment around the vehicle, in particular in order to widen visibility on one side of the road at least.
[0032] If required, the angular clearance permitted by the camera is between 0 and 15° or between 0 and 30°.
[0033] Still another object of the invention is also a detection device for a motor vehicle, this device comprising at least one camera which has a field of vision, this device being designed to:
receive information which is representative of a driving state associated with the vehicle; and modify the field of vision of the camera, in particular its orientation, according to the information.
[0036] Advantageously, the device comprises a DBL device which is associated with a headlight of a vehicle, the camera being coupled kinematically to the DBL device.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0037] The invention will be able to be better understood by reading the following detailed description of non-limiting embodiments of it, and by examining the attached drawing, in which:
[0038] FIG. 1A represents, schematically and partially, the situation on the road of a vehicle which is equipped with a camera according to the prior art, without a rotary headlight;
[0039] FIG. 1B represents, schematically and partially, the situation on the road of a vehicle which is equipped with a camera according to the prior art, with rotary headlights or DBLs;
[0040] FIG. 1C represents, schematically and partially, the situation on the road of a vehicle which is equipped with a detection device according to the invention, with rotary headlights or DBLs;
[0041] FIGS. 2 and 3 represent, schematically and partially, in perspective, devices according to two embodiments of the invention; and
[0042] FIG. 4 represents, schematically and partially, a situation on an urban road of a vehicle which is equipped with a device according to another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Night-time Context
[0043] An application specific to night-time is known, which consists of automation of the lighting, that is, an application which makes it possible to tilt from the low-beam light to the high-beam light or vice versa, according to vehicles which are potentially arriving opposite and which vehicles are detected automatically by a camera.
[0044] In certain cases of very tight bends, it has been shown that vehicles VI which are passing the vehicle V 1 which is equipped with the lighting automation function can be in the high beam Fr of the headlights of V 1 , and not be in the field of vision 1 of the camera 40 for a very short period of time (see FIG. 1A ).
[0045] The vehicles VI are in a situation of potentially being dazzled, which is reinforced by the action of a DBL (Dynamic Bending Light) device, as illustrated in FIG. 1B .
[0046] In this example in FIG. 1B , the camera is fixed, that is, it cannot pivot relative to the vehicle.
[0047] In contrast to FIGS. 1A and 1B , the DBL device in a motor vehicle headlight of the embodiment shown in FIGS. 1 C and 2 - 3 makes it possible to make an optical module pivot within the headlight.
[0048] The optical module can be of a low-beam light type and can pivot according to the trajectory which is being followed by the vehicle, in particular when the latter is cornering, in order to obtain a so-called “bending beam” or DBL.
[0049] Association of the movement of the camera with that of the DBL device reduces this risk of dazzling (as illustrated in FIG. 1C ).
[0050] According to all of the functions which are present in the vehicle V 1 , and in a non-limiting manner, a single camera is situated in the headlight on the passenger side or on the driver's side or two cameras are placed each in a headlight, or the camera is placed at the top of a windscreen W ( FIG. 4 ) on a platform.
[0051] In the case of one or more cameras which are placed in the headlights, the cameras can be fitted directly on the DBL device or can be physically connected to this device, as will be seen in greater detail hereinafter with reference to FIGS. 2 and 3 .
[0052] In the case of a camera at the top of the windscreen W, the movement of the camera is created by another platform which acquires information from the DBL device, or obtains directly the information concerning the steering wheel angle, which information controls the DBL device.
[0053] In general, all the information which is necessary for control of the movement of the DBL device, as well as the laws which govern this information, can be acquired by this platform.
[0054] In order to reduce the costs, it is possible to give precedence to implantation in the headlight(s), so as to benefit from the existing mechanical movement platforms.
[0055] Hereinafter in the description, there will be adoption on a non-limiting basis of a longitudinal, vertical and transverse orientation which is fixed relative to the motor vehicle bodywork, and is indicated by the trihedron L, V, and T in FIG. 2 .
[0056] FIG. 2 shows a motor vehicle headlight 10 which in this case comprises a reflector 12 , inside which a lamp 14 is fitted. The headlight 10 can emit a light beam according to an optical axis O with a globally longitudinal orientation.
[0057] The reflector 12 and the lamp 14 form an optical module 15 .
[0058] The module 15 is fitted such as to rotate around a vertical axis A, relative to the bodywork 16 of the motor vehicle. For this purpose, the headlight 10 comprises, for example, two lower and upper journals 18 with the axis A.
[0059] The beam of the headlight 10 can thus be oriented according to a plurality of angular positions around the axis A, in a clearance interval which is delimited by two end angular positions.
[0060] Hereinafter in the description, a neutral angular position is defined, which corresponds to the angular position which the headlight 10 occupies when it lights the road according to the longitudinal axis L of the vehicle.
[0061] The neutral angular position occupies a median position in the clearance interval.
[0062] Thus, the optical axis O of the beam of the headlight 10 can pivot on both sides of the longitudinal axis L of the motor vehicle.
[0063] The headlight 10 is rotated by a DBL drive device 20 , which in this case comprises an electric motor 22 , for example a step-by-step or stepper motor, which comprises a rotary vertical shaft 24 . The motor 22 is fitted fixed relative to the bodywork 16 of the motor vehicle. A pinion 26 is provided at a free upper end of the shaft 24 .
[0064] The DBL drive device 20 also comprises a circular toothed sector 28 which extends on a horizontal plane in the form of a fan, from a top 29 to a toothed peripheral arc 31 , with a top 29 forming a center of a peripheral arc 31 .
[0065] A top 29 of the toothed sector 28 is fitted such as to rotate around the axis A, such that a toothed sector 28 is integral in rotation with the headlight 10 . The teeth 31 of the toothed sector 28 are engaged with the teeth of a pinion 26 , such that the motor 22 can rotate the headlight 10 by means of the toothed sector 28 .
[0066] The DBL drive device 20 optionally also comprises a printed circuit board 30 , which extends on a transverse vertical plane, and in this case is secured to the motor 22 .
[0067] If required, the drive device 20 comprises at least two Hall-effect sensors which are provided on the printed circuit board 30 .
[0068] With reference to the role of the sensors which make it possible to measure the angular position of the headlight beam in its clearance interval, reference can be made to patent FR 2 899 967, which is equivalent to U.S. Pat. No. 7,595,634, which is incorporated herein by reference and made a part hereof.
[0069] In the example in FIG. 2 , the camera 40 is placed in the headlight 10 , and is fitted directly on the DBL device 20 , for example, integrally with the axis of pivoting A of the lighting module.
[0070] As a variant, as illustrated in FIG. 3 , the camera 40 is placed in the headlight 10 , and is physically connected to the DBL device 40 , for example, by means of a toothed sector 41 that can rotate around an axis B, which, for example, is parallel to the axis A.
Town/Low Speed
[0071] Within the context of driving in town, both by day and by night, the cameras which are coupled to the DBL device can also be used in order to improve the visibility at low speed when vehicles are passing one another. In fact, when approaching narrow crossroads, in town, it happens frequently that there is no visibility to the left and/or to the right. In the case for example of driving on a narrow road in town, the buildings which are on the right or the left of the road can make the visibility difficult at the approach to a crossing, as shown in FIG. 4 .
[0072] The invention thus proposes to orient the cameras 40 , in particular in the right and left headlights, by means of the DBL device, in order to widen the visibility on both sides of the crossing.
[0073] As soon as the vehicle is in town at low speed (information available in the vehicle, or speed information, or GPS information for example), the DBL devices can automatically be oriented towards the exterior, in order to widen the field of visibility. In town, at low speed, since the need for lighting is less great than on the road in the countryside (because of the exterior lighting), the fact of moving the light beams apart does not cause any problem.
[0074] It will be appreciated that, in order to be more efficient, this device requires putting into place of a machine interface, which makes it possible to inform the driver of the presence of an obstacle or a vehicle. A display screen in the vehicle can be an appropriate interface for providing the driver with this information. The two images (left and right cameras) can be coupled to the same screen.
[0075] The camera is advantageously associated with the movement of the DBL device, in order to follow the beam at night, or to increase the cover of visibility of the cameras by day.
[0076] The night-time and daytime functions can be made compatible.
[0077] It will be appreciated that the invention is not limited to the above-described embodiments.
[0078] For example, the mobility of the light beam can be assured by use of an FBL (Fixed Bending Light) device.
[0079] In this case, there is no movement which is specific to the headlight.
[0080] In a non-limiting manner, the beam can be modified in its orientation and form by the successive activation or deactivation of different sources of light (which can for example be LEDs), or by movement inside the headlight (for example movement of a shield which is mobile inside the headlight).
[0081] In this case, the movement of the camera can be controlled by information concerning activation of the FBL (for example information concerning the angle on the steering wheel, or GPS data).
[0082] While the method herein described, and the form of apparatus for carrying this method into effect, constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention, which is defined in the appended claims. | A detection method, system and device for a motor vehicle (V 1 ). The method system and device uses at least one camera which has a predetermined field of vision. The method includes the following steps:
receiving information which is representative of a driving state associated with the vehicle; and modifying the field of vision of the camera, and in particular its orientation, according to the information. | 1 |
FIELD OF THE INVENTION
The invention relates generally to the field of photography, and in particular to cameras. More specifically, the invention relates to light-sensitive user aids for cameras having manually activated flash assemblies.
BACKGROUND OF THE INVENTION
Expensive electronic flash cameras have a light meter or other exposure measuring device contained within the camera which sense the amount of ambient light present for the scene being photographed and automatically fires the flash assembly if the sensed lighting conditions will not produce an effective exposure.
In a number of more inexpensive cameras, such as single use cameras manufactured by the Eastman Kodak Company and Fuji Photo Film Co., Ltd., the flash assembly is manually operated, typically by an actuable switch located on the exterior of the camera body which charges the flash assembly for firing when the shutter release button is depressed. Prior to capturing an image, the average user must make a decision, gauged on the amount of ambient lighting perceived visually by the user, whether or not to charge the flash assembly. Improper decisions regarding the use of the flash may subsequently produce inconsistent results, resulting in consumer dissatisfaction.
In some other instances, such as when there is indoor lighting, the user should be guided or reminded to activate the flash prior to image capture given that a high percentage of pictures requiring flash are taken under these conditions.
There is a need then, to provide an aid to consumers, preferably for inexpensive cameras having a manually operable flash assembly, which allows the user to correctly operate the flash when needed.
SUMMARY OF THE INVENTION
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, there is provided an apparatus for a camera having a body and a manually operated flash assembly, characterized by:
sensing means disposed on said camera body, and made from a material having properties which vary depending on the amount of incident light striking the sensing means; and
reference means having a specific property value for comparing to said sensing means for visually indicating whether said flash assembly should be powered.
According to another aspect of the present invention, there is described a method for using a camera having a manually operated flash assembly comprising the steps of:
reading the optical density of a displayed light sensing element made from a material which varies in optical density depending on the amount of light incident thereupon;
comparing the optical density of the light sensing element with the optical density of an adjacently disposed reference standard having a fixed optical density; and
activating the flash assembly if the optical density of the sensing element is markedly different than that of the reference standard.
An advantageous feature of the present invention is that enabling information is provided to the user for properly and consistently utilizing the manual flash assembly, thereby producing higher quality images and increasing user satisfaction.
Another advantageous advantage of the present invention is that a flash indication device is inexpensively provided without significant impact on the cost of the camera including such a device.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following Detailed Description of the Preferred Embodiments and appended claims, and by reference to the accompanying Drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1(a) is a front perspective view of a camera having a flash indication aid according to a first embodiment of the present invention;
FIG. 1(b) is a graphical representation of the properties of the light pipe element of the flash indication aid of FIG. 1(a);
FIG. 1(c) illustrates the use of the flash indicating aid of FIGS. 1(a) and 1(b);
FIG. 2(a) is a front perspective view of the camera of FIGS. 1(a) having a flash indication aid according to a second embodiment of the present invention; and
FIG. 2(b) is a comparative pictorial representation of the flash indication aid of FIG. 2(a), illustrating an example of the aid in use.
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment according to the present invention is described. Referring to FIGS. 1(a)-1(c), and specifically to FIG. 1(a), there is provided a camera, such as the FUNSAVER™ single-use camera 10 manufactured by Eastman Kodak Company which is defined by a plastic body 12 having a taking lens 14 attached to the front portion of the body along with a viewfinder 16, a flash illumination assembly 18 powered for use by a manually activatable charging switch 19 located on the front of the body 12, and a shutter release button 20. Electronics (not shown) between the shutter release button 20 and the flash assembly 18 allows the firing of the flash after the charging switch 19 is activated by the user, as is commonly known. Further, each of the above described features and their method of operation are commonly known to one of ordinary skill in the field of photography. Therefore, further discussion relating to these features is not required.
A light-pipe element 22 is provided in a cavity 21 of the body 12 and includes a light gathering end 24 extending from the front exterior surface of the body 12, and a viewing end 26 extending from the top surface of the body. The light-pipe element 22 is made from PVC or other similar material which allows allow light transmission from the light-receiving end 24 to the viewing end 26, such as when the light-pipe element is exposed to ambient light. In addition, the viewing end 26 is preferably treated with a dye, such as T 1 O 2 or other similar material, which changes optical density, such as by changing color, based on the amount of light transmitted through the light-pipe element 22 from the light receiving end 24.
A reference strip 28 is adhered or otherwise attached to the top surface of the body 12, preferably adjacent the viewing end 26 of the light-pipe element 22.
The dye in the viewing end 26 causes the light-pipe element 22 to vary in optical density, as shown in FIG. 1(b), such that the optical density of the viewing end 26 decreases with a corresponding increase in illumination; in this case the viewing end 26 gets perceivably lighter in color as the illumination level of the ambient light increases.
The reference strip 28 is made from a printed or other material having a known, fixed optical density, (in this case, a specific color), defined by point B in FIG. 1(b), and more specifically shown in FIG. 1(c). The color of the reference strip preferably and according to this particular embodiment represents the color of the viewing end 26 at the minimum level of illumination for which the flash assembly 18 is not required. See FIG. 1(b).
In operation, and referring to FIGS. 1(a)-1(c), the user points the camera 10 toward the subject to be photographed in a manner conventionally known, whereby the user spots the subject through the viewfinder 16. The level of ambient light present for the scene to be photographed is received by the light gathering end 24, and is transmitted to the viewing end 26. The intensity of the transmitted light changes the optical density of the viewing end 26 in accordance with the linear relationship defined by FIG. 1(b). The user then compares the optical density (that is, the color) of the viewing end 26 with the optical density of the reference strip 28. If the color of the viewing end 26 is darker than the fixed color of the reference strip 28, as shown in the top example of FIG. 1(c), then an insufficient amount of light is present for image capturing and the flash assembly 18 should be charged for firing by the user by means of switch 19, prior to depressing the shutter release button 20. If on the other hand, the color of the viewing end 26 is lighter than or the same as that of the reference strip 28, then adequate ambient light is present to capture an image, and the user need only depress the shutter release button 20.
A second embodiment is herein described with reference to FIGS. 2(a) and 2(b). Similar parts used in the preceding embodiment are labeled with the same reference numerals for the sake of clarity.
Referring specifically to FIG. 2(a), there is shown a camera 10, defined by a plastic body 12 and having a taking lens 14 attached to the front exterior portion of the body, as well as a viewfinder 16. The camera also includes a flash illumination assembly 18 which is charged for firing by an manually actuable switch 19 located on the front surface of the body 12, and a shutter release button 20 located on the top surface of the body. It should be readily apparent from the discussion presented that the locations of each of the photographic elements are not specifically limited; for example, the charge switch 19 could be located along a side surface or the top surface of the body 12.
Attached to the top surface of the body 12 is a flash indicating aid 30 which is adhered or otherwise attached to the camera 10. Preferably, according to this embodiment, the aid 30 consists of two visible and adjacently disposed portions 32, 34.
Portion 32, is made from a metamaric material, which varies in optical density based on the type of light source, as opposed to the level of illumination regardless of the light source as in the previous embodiment, thereby acting as a light sensing element. It is known that a high percentage of flash pictures are taken in environments illuminated by tungsten light sources, such as indoor overhead lighting. In this simplified example, portion 32 varies in optical density (in this case, color) differently when exposed to a tungsten lighting source, than when exposed to daylight conditions; that is, portion 32 becomes darker under a tungsten light source than under daylight conditions, for the same illumination level, see FIG. 2(b).
Adjacent portion 34, on the other hand, is made from a material having a fixed optical density which does not vary when other light sources, such as tungsten or daylight, are used. Preferably, as in the preceding embodiment, the optical density of portion 34 is equivalent to the optical density of portion 32 which is attained when a tungsten lighting source is used.
In use, the user points the taking lens 14 of the camera 10 at the subject to be photographed, as is conventionally known. Portion 32 being exposed to the ambient light conditions then undergoes a change in optical density (in this case, color) based on the type and level of ambient light available. In this particular example, portion 32 is darker than portion 34 when used in an environment using a tungsten light source versus a daylight light source in which portion 32 is lighter than or equal to the same color as portion 34. See FIG. 2(b).
A determination as to whether the flash assembly 18 should be charged by actuating switch 19 can then be made by the user by comparing the colors or shades of colors of the adjacent portions 32, 34. In this particular embodiment, if portion 32 is perceivably darker than reference portion 34, then the switch 19 should be actuated.
It should be readily apparent from the preceding discussion that the sensing element can be made from other materials can be introduced which vary depending on either/or illumination levels and/or types of lighting which can be used as a sensing element. For example a metameric ink (not shown) can be applied to a printed reference strip in which a lettered message such as "TURN FLASH ON" will appear when exposed to tungsten lighting. This serves as a guide or reminder for the user to activate the flash prior to image capture.
It should also be understood that although the present invention has been described by way of the preferred embodiments, it is to be noted that various changes and modifications will be apparent to those skilled in the art. For example, a plurality of indicator aids could be placed on a camera with one or more reference standards to accommodate a myriad of possible lighting scenarios. Other similar combinations in the spirit and scope of the invention can also be contemplated.
PARTS LIST FOR FIGS. 1(a)-2(b)
10 camera
12 body
14 taking lens
16 viewfinder
18 flash assembly
19 switch
20 shutter release button
21 cavity
22 light pipe element
24 light receiving end
26 viewing end
28 reference strip
30 flash indication aid
32 metameric portion
34 reference portion | A device for a camera having a manually operated flash assembly includes a sensing element made from a photochromic, metameric or other material which is capable of producing visible optical density changes, such as color changes, based on the level of incident light impinging on the element. According to the invention, a reference standard having a specific optical density is adjacently positioned relative to the sensing element so that the respective optical densities can be compared prior to image capture in order to guide the user whether or not to use the flash. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/596,019, filed Aug. 24, 2005, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention generally relates to thermodynamic systems, and more particularly to thermodynamic systems operating according to the Ericsson or Brayton cycle and capable of achieving near-isothermal compression and expansion of a gas by mixing therewith a substantial quantity of liquid.
A refrigeration machine, heat pump, or cooler can be defined as any device that moves heat from a low temperature source to a high temperature sink. Operation of a refrigeration machine requires an input of energy, usually thermal, mechanical or electrical. Depending on the specific need, the heat absorbed in the low temperature source can be utilized to provide cooling, or the heat rejected to the high temperature sink can be used to provide heating, or both may be utilized simultaneously. As an example, for a typical household refrigerator the low temperature source is the space inside the refrigerator and the high temperature sink is the air in the room where the refrigerator is placed. Electrical energy is typically used to operate the system.
With the exception of a few niche applications, virtually all refrigeration machines operate on the vapor-compression (V-C) cycle. Common examples include home and automobile air conditioners, domestic and industrial food refrigeration, commercial comfort cooling, industrial process cooling, and many others. The traditional refrigerant fluids used in these machines contain compounds that result in ozone depletion if they escape into the upper atmosphere. These ozone depleting refrigerants are in the process of being phased out and eventually banned. However the new refrigerants, while not posing a risk to the ozone layer, are very potent greenhouse gasses. Other refrigerants that don't pose a substantial environmental risk have other drawbacks, such as being flammable or toxic. One such example is ammonia, which is an excellent refrigerant from a system performance perspective, but is highly toxic. There is a great need and much work is being done to develop and commercialize practical refrigeration systems that do not require the use of environmentally hazardous refrigerants.
The reverse Ericsson cycle is an alternative refrigeration cycle capable of operating with benign refrigerants, such as air, argon, xenon, and helium. The Ericsson cycle combines four thermodynamic processes. For an ideal cycle that uses a gas as the working material, the processes are isothermal (constant temperature) compression, constant pressure heat rejection from the high pressure stream to the low pressure stream, isothermal expansion, and constant pressure heat addition to the low pressure stream from the high pressure stream. A system that approximates these processes can be termed an Ericsson device or machine. The Ericsson cycle has several notable advantages. For example, the cycle is thermodynamically reversible, meaning that its coefficient of performance (COP) is theoretically the same as the Carnot COP, which is the maximum efficiency any refrigeration machine can achieve while operating between given temperatures. Another advantage of the Ericsson cycle is that it can use fluid refrigerants that pose no or low environmental risk. Virtually any gas can be used as the working fluid, including the aforementioned air, argon, xenon, and helium as well as other readily available gases such as carbon dioxide.
The principle difficulty of implementing a practical device that operates in a manner substantially similar to the Ericsson cycle is the requirement for isothermal or near isothermal compression and expansion of the working fluid to achieve a reasonable efficiency. When a gas is compressed, the temperature of the gas increases. To keep the temperature of the gas constant during compression, the gas must be cooled while it is compressed. In practice, isothermal compression of a gas is extremely difficult to achieve because, for practical compression machines, the area available for heat transfer is very small and the compression process occurs very quickly. Slowing down the compression process or increasing the surface area for heat transfer leads to very large, impractical, and expensive machinery.
U.S. Pat. No. 4,984,432 to Corey discloses an Ericsson cycle machine that uses liquid ring compressors to compress and expand a gas-liquid mixture. However, several disadvantages are believed to exist with this machine as disclosed. First, liquid ring compressors have difficulty producing large pressure differentials, which can result in small volumetric capacities and necessitate large equipment to achieve relatively small cooling capacities. Liquid ring compressors also exhibit low efficiencies due in part to high viscous (fluid friction) losses, resulting in tremendous degradation of performance. Furthermore, the power required to pump the liquid through the heat exchanger loops is substantial, with no means disclosed to recover this power. Another shortcoming is that the liquid ring is simultaneously in substantial thermal contact with both the inlet and outlet gas streams, which has the undesirable effect of preheating the suction gas on the compression side and precooling the inlet gas on the expander side and results in higher compression work and lower expander work recovery, respectively. In any event, a thermodynamic analysis of the cycle is not presented in the Corey patent, and attempts to test the disclosed Ericsson cycle machine have failed to achieve a net heat pumping effect.
BRIEF SUMMARY OF THE INVENTION
The invention pertains to a thermodynamic system that can approximate the Ericsson or Brayton cycles and operated in reverse or forward modes to implement a refrigeration device (e.g., a cooler or heat pump) or engine, respectively.
The thermodynamic system includes a device for compressing a first fluid stream containing a first gas-liquid mixture having a sufficient liquid content so that compression of the gas within the first gas-liquid mixture by the compressing device is nearly isothermal, and a device for expanding a second fluid stream containing a second gas-liquid mixture having a sufficient liquid content so that expansion of the gas within the second gas-liquid mixture by the expanding device is nearly isothermal. A heat sink is in thermal communication with at least the liquid of the first gas-liquid mixture for transferring heat therefrom, and a heat source is in thermal communication with at least the liquid of the second gas-liquid mixture for transferring heat thereto. Finally, a device is provided for transferring heat between at least the gas of the first gas-liquid mixture after the first fluid stream exits the compressing device and at least the gas of the second gas-liquid mixture after the second fluid stream exits the expanding device. According to the invention, the compressing and expanding devices are not liquid-ring compressors or expanders, but instead are devices that are very tolerant of liquid flooding, such as scroll-type compressors and expanders.
The current invention overcomes the difficulty of achieving isothermal compression and expansion in Ericsson and Brayton cycles (or approximations thereof) by mixing a substantial quantity of liquid into the gas during the compression and expansion processes. Since the liquid is in intimate contact with the gas, and can be injected in the form of a mist to promote contact, excellent heat transfer between the gas and liquid is able to occur. Because the liquid have a larger thermal mass compared to the gas being compressed, the liquid absorbs a large amount of the heat of compression. The temperature of the gas therefore remains nearly constant during the compression process. Benefits to the expansion process are analogous.
It should be noted that flooding with liquid will damage most gas compression and expansion machines because, unlike a gas, a liquid is substantially incompressible. Therefore very large forces are produced on compression and expansion machinery if an attempt is made to compress a liquid. However, scroll compressors and expanders have been shown to be very tolerant of liquid flooding when implemented with the thermodynamic system of this invention. Because the volume ratio of a scroll compressor is fixed and relatively small, a scroll compressor is able to accommodate liquid within compression pockets in the compressor. In addition to scroll-type compressors, other types of compressors are believed to be tolerant of liquid flooding, particularly screw compressors. In addition, vane-type rotary compressors can also be configured to accommodate liquid flooding to the extent necessary for use in the present invention.
Another advantage of the invention is the ability to use many different liquids in the thermodynamic system, including water, mineral oil, or natural biodegradable oils such as rapeseed oil. One advantage of using an oil as the heat transfer fluid is that it can also be used as the lubricant for mechanical components in the system. In addition, because oils are generally strong dielectrics, their use can be combined in a hermetic system that encloses mechanical components of the system, such as electric motors used to drive the compressor.
Other objects and advantages of this invention will be better appreciated from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of a thermodynamic system operating as an Ericsson cycle cooler with liquid flooding in accordance with an embodiment of this invention.
FIG. 2 is a schematic of a modified thermodynamic system operating as an Ericsson cycle cooler with liquid flooding in accordance with another embodiment of this invention.
FIG. 3 is a schematic of a thermodynamic system similar to that of FIG. 1 , but modified to operate as an Ericsson cycle engine in accordance with an embodiment of this invention.
FIG. 4 is a schematic of a thermodynamic system operating as a Brayton cycle cooler with liquid flooding in accordance with an embodiment of this invention.
FIG. 5 is a schematic sectional view of integral compression, expansion, and separation machinery for use with an Ericsson cycle system of this invention.
FIG. 6 is a schematic of a modified thermodynamic system operating as an Ericsson cycle cooler with liquid flooding in accordance with an embodiment of this invention.
FIGS. 7 and 8 are schematics of Ericsson cycle coolers similar to FIG. 1 , but further equipped with means for equalizing the amount of flooding liquid within two liquid circuits of the system in accordance with an embodiment of this invention.
FIG. 9 is a schematic of an Ericsson cycle cooler similar to FIG. 1 , but further equipped with additional heat exchangers to improve the performance of the system as a heat pump or heat engine in accordance with an additional embodiment of this invention.
FIG. 10 is a schematic of an Ericsson cycle cooler similar to FIG. 1 , but with heat exchangers relocated.
FIG. 11 is a schematic of an Ericsson cycle cooler similar to FIG. 1 , but modified to use ejectors.
FIG. 12 is a schematic of a modified Brayton cycle cooler similar to FIG. 4 .
DETAILED DESCRIPTION OF THE INVENTION
The invention is described in reference to thermodynamic systems that employ Ericsson or Brayton cycles in combination with liquid flooding during compression and expansion of a compressible fluid so that the compression and expansion processes are nearly isothermal. As will be evident from the following, numerous liquids can be used as the flooding liquid and numerous gases can be used as the compressible fluid. Particular examples of suitable compressible fluids include air, argon, xenon, helium, etc., though others could also be used, with a preference for fluids that are not toxic, flammable, ozone-depleting, or potent greenhouse gases. Particular examples of suitable liquids include water, mineral oil, natural biodegradable oils such as rapeseed oil, etc. In some cases, nonvolatile liquids will likely be preferred, though it is believed that the use of a liquid (e.g., water) that partially vaporizes and condenses as it goes through compression and expansion, respectively, would result in more isothermal compression and expansion at lower liquid flooding rates, which has potential advantages. Those skilled in the art will appreciate that suitable temperatures, pressures, etc., for the operation of the systems will depend on the particular liquids and gases used.
Those skilled in the art will also appreciate that compressors and expanders suitable for use with the invention must be tolerant of liquid flooding. While scroll-type compressors and expanders will be described in reference to the multiple embodiments of this invention, the thermodynamic system can be implemented using other types of compressors and expanders that are relatively tolerant of liquid flooding, including but not limited to screw compressors, rotary vane compressors, diaphragm compressors, and even rotary and reciprocating piston compressors if sufficient clearance volume is introduced to prevent damage to components. Furthermore, it is foreseeable that centrifugal machine could be modified or designed for this purpose. The construction and operation of such compressors and expanders are well documented in the art, and therefore will not be repeated here.
In reference to FIG. 1 , a thermodynamic system is represented as a reverse Ericsson cycle system 10 that employs a scroll compressor 12 and scroll expander 44 . In FIG. 1 , a low-pressure high-temperature gas-liquid mixture 14 enters the compressor 12 and is compressed to a higher pressure. (In the Figures, liquid streams are represented by a solid line, gas streams are represented by a dashed line, and gas-liquid mixtures are represented by combined solid and dashed lines.) Because the liquid and gas are in intimate thermal contact during compression and the thermal capacitance of liquids is typically significantly greater than that of the gas within the mixture 14 , the system 10 is operated so that the heat of compression of the gas within the mixture 14 is absorbed by the liquid within the mixture 14 , preferably to the extent that the gas is compressed nearly isothermally. This relationship can be quantified as the capacitance rate ratio (C ratio ), defined as
C ratio =m l c l /m g c p.g.
where m l and c l are respectively the mass flow rate and thermal capacitance of the liquid, the product of m l and c l is the thermal capacitance rate of the liquid, m g and c p.g. are respectively the mass flow rate and thermal capacitance of the gas, and the product of m g. and c p.g. is the thermal capacitance rate of the gas. From the above equation, it is evident that the C ratio of the system 10 will depend on the particular gas and liquid used and their relative amounts. In some cases, the thermal capacitance rate of the liquid may be much greater than that of the gas (i.e., Cratio>>1). However, it is believed that in some cases the system 10 can operate with a C ratio of approximately 1. In all cases, the relative amount of liquid in the gas-liquid mixture 14 (in other words, the liquid flooding during compression and, as discussed below, during expansion) should be substantial enough to significantly reduce the temperature change of the gas during the compression process (as well as during the expansion process).
The compressor 12 is indicated as being powered (P c ) by an electric motor or other suitable device (not shown). The high-pressure high-temperature gas-liquid mixture 16 exiting the compressor 12 enters a high temperature gas-liquid separator 18 , which can be of a type well known in the art. A high-pressure high-temperature liquid stream 20 and a high-pressure high-temperature gas stream 22 separately exit the separator 18 , from which the liquid stream 20 enters a liquid circuit containing a liquid motor 24 that reduces the pressure of the liquid stream 20 to a relatively low level. Work (P m ) from the liquid motor 24 can be recovered and used to drive the compressor 12 and/or other devices within the system, such as a liquid pump 42 within a second liquid circuit of the system 10 . The resulting low-pressure high-temperature liquid stream 26 exits the liquid motor 24 and enters a high-temperature heat exchanger 28 , where heat from the low-pressure high temperature liquid stream 26 is rejected to a high-temperature sink (Q out ) The resulting low-pressure high-temperature liquid stream 30 exiting the heat exchanger 28 is subsequently mixed with a low-pressure high-temperature gas stream 32 to reform the low-pressure high-temperature gas-liquid mixture 14 delivered to the compressor 12 .
The high-pressure high-temperature gas stream 22 separated by the separator 18 enters a regenerator 34 , where heat (Q R ) from the gas stream 22 is rejected to a low-pressure low-temperature gas stream 36 (discussed below). The resulting high-pressure low-temperature gas stream 38 that exits the regenerator 34 preferably has a temperature near that of a refrigerated space 56 cooled by the second liquid circuit of the system 10 . The gas stream 38 mixes with a high-pressure low-temperature liquid stream 40 from the liquid pump 42 , forming a high-pressure low-temperature gas-liquid mixture 46 that enters the scroll expander 44 . Within the expander 44 , the gas-liquid mixture 46 is expanded nearly isothermal as a result of intimate thermal contact between the liquid and gas during expansion and the significantly greater thermal capacitance of the liquid. The expander 44 produces work (P e ) that can be used to provide power for other components of the system 10 , including the compressor 12 and liquid pump 42 , through various known arrangements such as direct shaft coupling. The resulting low-pressure low-temperature gas-liquid mixture 48 then enters a low-temperature gas-liquid separator 50 , which separates the gas-liquid mixture 48 into a low-pressure low-temperature liquid stream 52 and the aforementioned low-pressure low-temperature gas stream 36 .
The low-pressure low-temperature liquid stream 52 enters a cold heat exchanger 54 , where the liquid stream 52 absorbs heat from the refrigerated space 56 . The resulting low-pressure low-temperature liquid stream 58 exiting the cold heat exchanger 54 enters the liquid pump 42 , where its pressure is increased to the high system pressure. The low-pressure low-temperature gas stream 36 from the low-temperature gas-liquid separator 50 enters the regenerator 34 , where it absorbs heat from the high-pressure high-temperature gas stream 22 separated by the high-temperature gas-liquid separator 18 . The resulting low-pressure high-temperature gas stream 32 exiting the regenerator 34 is at a temperature near the hot side temperature of the system 10 , i.e., near that of the low-pressure high-temperature liquid stream 30 .
The reverse Ericsson cycle of the system 10 operates in a continuous fashion as described. The locations of the liquid motor 24 and liquid pump 42 can be on either side of the heat exchangers 28 and 54 , respectively. Furthermore, the liquid motor 24 can be replaced with a throttling valve (not shown), though with a loss in system performance. If so desired, different liquids can be used in the hot side of the system 10 (to the left of the regenerator 34 in FIG. 1 ) and cold side of the system 10 (to the right of the regenerator 34 in FIG. 1 ). As an example, the use of different liquids can be advantageous if the system 10 operates under extreme temperature differentials where a single liquid would either vaporize or solidify at the hot and cold sides, respectively. For instance, a cryogenic application for the system 10 could use water or oil on the hot side of the system 10 and liquid nitrogen on the cold side of the system 10 , with helium or nitrogen used as the gas for the gas loop.
FIGS. 2 through 12 depict additional thermodynamic systems in accordance with further embodiments of this invention. For convenience, in these Figures consistent reference numbers are used to identify functionally similar structures.
FIG. 2 is an alternative reverse Ericsson cycle system 100 to that of FIG. 1 , with the primary difference being the elimination of the liquid motor 24 and liquid pump 42 . In this embodiment, the gas-liquid mixture 14 enters the scroll compressor 12 , where it is compressed nearly isothermally and exits the compressor 12 before entering the separator 18 . As before, the separator 18 separates the liquid and gas of the mixture 16 , and the resulting high-pressure high-temperature liquid stream 20 enters the high temperature heat exchanger 28 where heat (Q out ) is rejected from the liquid stream 20 to the high-temperature heat sink. In contrast to the embodiment of FIG. 1 , the high-pressure high-temperature liquid stream 20 then enters a liquid regenerator 60 , where heat (Q L ) is rejected to the low-pressure low-temperature liquid stream 58 from the low temperature heat exchanger 54 . The high-pressure liquid stream 40 exiting the liquid regenerator 60 is now at a low temperature, and is then mixed with the high-pressure low-temperature gas stream 38 before entering the scroll expander 44 . As before, the resulting high-pressure low-temperature gas-liquid mixture 46 is expanded nearly isothermally by the expander 44 , after which the liquid and gas constituents of the now low-pressure low temperature gas-liquid mixture 48 are separated by the separator 50 . The low-pressure low-temperature liquid stream 52 enters the cold heat exchanger 54 , where the liquid absorbs heat from the refrigerated space 56 . The low-pressure low-temperature liquid stream 58 then enters the liquid regenerator 60 , where it absorbs heat from the high-pressure high-temperature liquid stream 20 . The resulting low-pressure high-temperature liquid stream 30 exits the liquid regenerator 60 and is subsequently mixed with the low-pressure high-temperature gas stream 32 before entering the compressor 12 . In view of the foregoing, the functions of the gas streams 22 , 32 , 36 , and 38 are essentially the same as in the embodiment of FIG. 1 . Work produced by the expander 44 can be used to offset some of the power (P c ) required by the compressor 12 .
FIG. 3 is an embodiment of the Ericsson cycle set forth in FIG. 1 , but operated in a forward mode as a heat engine 200 . Operated as an engine, the system 200 uses the expander-side heat exchanger 54 to absorb heat (Q in ) from a high temperature heat source, with the result that the gas-liquid mixture 48 downstream of the expander is at low pressure but high temperature. On the compressor side, heat (Q out ) is rejected from the liquid stream 26 to a low temperature heat sink, with the result that the gas-liquid mixture 16 downstream of the compressor 12 is at high pressure but low temperature. Because the temperatures of the gas and liquid streams on the expander-side of the system 200 are elevated relative to the gas and liquid streams on the compressor-side of the system 200 (opposite that of FIG. 1 ), the regenerator 34 operates to transfer heat from the low-pressure high-temperature gas stream 36 downstream of the expander 44 to the high-pressure low-temperature gas stream 22 downstream of the compressor 12 . The expander work (P e ) is greater than the compressor work (P w ) and a net power output is achieved. A portion of the expander work (P e ) can be delivered to the compressor 12 through a shaft (not shown). Otherwise, the individual components of the system 200 in FIG. 3 operate in a very similar manner to the identical components of the system 10 in FIG. 1 .
FIG. 4 is a schematic of a reverse Brayton cycle system 300 utilizing a scroll compressor 12 and scroll expander 44 with liquid flooding, similar to FIGS. 1 and 2 . Most notably, the entire system 300 operates on a mixture of gas and liquid, with essentially only pressure and temperature being variable. A low-pressure high-temperature gas-liquid mixture 62 enters the compressor 12 , where it is compressed nearly isothermally. The resulting high-pressure high-temperature gas-liquid mixture 64 enters the hot heat exchanger 28 , where the mixture 64 rejects heat to a high-temperature heat sink. The resulting high-pressure high-temperature gas-liquid mixture 66 exits the heat exchanger 28 and enters the regenerator 34 , where heat (Q R ) is reject to a low-pressure low-temperature gas-liquid mixture 68 . The resulting high-pressure gas-liquid mixture 70 , now at a low temperature, enters the expander 44 where it is expanded nearly isothermally. The resulting low-pressure low-temperature gas-liquid mixture 72 exits the expander 44 then enters the cold heat exchanger 54 , where heat is absorbed from the refrigerated space 56 . The resulting low-pressure low-temperature gas-liquid mixture 68 exits the cold heat exchanger 54 and enters the regenerator 34 , where heat is absorbed from the high-pressure, high-temperature gas-liquid mixture 66 . The work (P e ) produced by the expander 14 can be used to offset some of the work (P c ) required by the compressor 12 .
The embodiment of FIG. 4 is more efficient than a simple reverse Brayton gas cycle because the compression and expansion processes occur nearly isothermally. As with the Ericsson cycle systems 10 and 100 of FIGS. 1 and 2 , the system 300 of FIG. 4 can be operated as a heat engine by replacing the refrigerated space 56 with a high-temperature heat source. In this case, the heat exchanger 28 becomes a low temperature heat sink. Notably, the flow direction of the gas-liquid mixture is also reversed.
FIG. 5 represents a sectional view of a portion of any one of the Ericsson systems of FIGS. 1 and 3 , in which the compressor 12 , expander 44 , liquid motor 24 , liquid pump 42 , and separators 18 and 50 are part of an integral unit 74 . The scroll compressor 12 and scroll expander 44 are axially opposed in a common shaft 76 . A motor rotor 78 is located between the compressor 12 and expander 44 on the shaft 76 . The liquid pump 42 and liquid motor 24 are also driven by shaft 76 . The separators 18 and 50 are located on opposite ends of the unit 74 . The remaining components attach to the unit 74 through open-ended connections as shown. The integral unit 74 greatly simplifies the system designs shown schematically in FIGS. 1 and 3 . By eliminating the liquid motor 24 and liquid pump 42 , the integral unit 74 is further simplified for use with the system 200 shown schematically in FIG. 2 , and could also be used with additional modifications for implementation of the Brayton cycle system 300 of FIG. 3 .
FIG. 6 shows a schematic representation of an open Ericsson cooler system 400 that operates in the same manner as the system of FIG. 1 , with the exception that the low-pressure low-temperature gas stream 36 exiting the separator 50 is in fluid communication with the refrigerated space 56 , such that the gas stream 36 A that is passed through the regenerator 34 is drawn from the refrigerated space 56 .
In principle, the liquids in the hot and cold loops of the system 10 represented in FIG. 1 are isolated from each other and do not intermix. In practice, however, the hot-side and cold-side separators 18 and 50 will not be able to entirely remove the liquids from each gas-liquid mixture 16 and 48 , so that the gas streams 22 , 32 , 36 , and 38 flowing between both sides of the system 10 will transport liquid from one side to the other. Due to normal manufacturing variations and differences in flow velocities and other conditions between the separators 18 and 50 , it will likely always be the case that gas flowing from one side of the system 10 will contain more liquid than gas flowing from the other side of the system 10 . Under this assumption, after many hours of running, liquid will accumulate on one side of the system 10 . To prevent this, means can be provided for equalizing the liquid between the two sides of the system 10 . While various techniques can be devised to accomplish this, a passive equalization system and an active equalization system are shown for this purpose in FIGS. 7 and 8 .
In FIG. 7 , flow paths 80 and 82 can be formed by tubes that pierce the separators 18 and 50 , respectively, at the approximate levels that the liquids are to be maintained in the separators 18 and 50 . At the downstream end of the flow path 80 , the tube is in fluid communication with, for example, the gas-liquid mixture 46 upstream of the expander 44 , while the downstream end of the flow path 82 fluidically communicates with, for example, the gas-liquid mixture 14 upstream of the compressor 12 . Because of flow losses, the pressures at the downstream ends of the flow paths 80 and 82 are slightly lower than at the separators 18 and 50 , such that pumps are not required for equalization. FIG. 8 addresses a situation in which there is a tendency for liquid to accumulate in the separator 18 . The flow path 80 is equipped with a float-type metering valve that opens and allows liquid to flow to the separator 50 when the liquid level in the separator 18 reaches a predetermined level.
As previously noted, the compression and expansion processes of the various systems shown in the Figures will be nearly isothermal if sufficient liquid is mixed with the gas during compression and expansion. In practice, however, there will still likely be a temperature rise or drop during flooded compression and expansion, respectively, in which case it can be advantageous to place additional heat exchangers 86 and 88 as shown in FIG. 9 . The additional heat exchangers 86 and 88 are in an arrangement similar to a Brayton cycle cooler, and serve to improve the performance of an Ericsson cycle system, whether for a heat pump (e.g., FIG. 1 ) or a heat engine (e.g., FIG. 3 ).
FIG. 10 represents a further modification of FIG. 1 in which the heat exchangers 28 and 54 are relocated directly downstream of the compressor 12 and expander 44 , respectively. These locations allow for additional heat to be rejected (Q out ) and additional heat to be absorbed (Q in ), with the net effect that the coefficient of performance (COP) can be improved for the system 10 . The improvement in COP is possibly such that the system of FIG. 10 is believed to be a preferred configuration for a reverse Ericsson cycle system of this invention.
In another embodiment shown in FIG. 11 , the liquid motor 24 and pump 42 are replaced with ejectors 90 and 92 , respectively. As known in the art, ejectors use a high pressure fluid stream to compress a low pressure fluid stream to an intermediate pressure. Therefore, in the embodiment of FIG. 11 , the ejector 90 is employed to reduce the pressure of the liquid stream 30 entering the compressor 12 , and the ejector 92 is employed to increase the pressure of the liquid stream 40 entering the expander 44 .
The liquid motor 24 can also be replaced in any of the embodiments with a throttle valve 94 (or other suitable type of flow restriction), as represented in FIG. 12 with the Brayton cycle system of FIG. 4 . A flow restriction is a much simpler and lower cost approach than the liquid motor 24 , such as a hydraulic motor. However, system efficiency will decrease since no work is being recovered from the liquid stream as its pressure is reduced with the restriction.
In an investigation leading up to this invention, an experimental liquid-flooded Ericsson cooler system corresponding to the system 10 represented in FIG. 1 was constructed and used to perform tests. In the construction of the system, primarily off-the-shelf parts with very little modifications were used. The sizing of components used in the system was based on preliminary modeling results reported in Hugenroth et al., “Liquid-Flooded Ericsson Cycle Cooler: Part 1-Thermodynamic Analysis,” Proceedings of the 2006 International Refrigeration and Air Conditioning Conference at Purdue, R168, the contents of which are incorporated herein by reference. Open drive scroll compressors were chosen for the compressor and expander in the experimental system. In addition to being readily available at low cost and at the approximate displacement volume desired, a scroll compressor can be operated as an expander by simply reversing the fluid flow through the machine.
The experimental system contained the following major components: compressor, expander, hydraulic motor, pump, hot and cold separators, hot and cold mixers, hot and cold heat exchangers, and a regenerator. The heat exchangers were commercially-available units that exchanged heat with an aqueous ethylene glycol coolant supplied by a chiller system. The regenerator was also a commercially available heat exchanger. The separators were custom-built units having a first stage for simple gravity separation of the liquid from the gas, and commercially-available centrifugal type oil separators formed a second stage to separate remaining oil from the gas. Mixing of the liquid and gas streams was accomplished simply by bringing the two streams together at a tee in the lines. Nitrogen and alkyl-benzene oil were used as the refrigerant and flooding liquid, respectively, in the experimental system.
The compressor, expander, hydraulic motor, and pump were coupled to electric motors to allow for independent speed control of each component. The expander and hydraulic motor produced power and the electric motors coupled to these components operated regeneratively. Torque cells were placed between the motor shafts and the shaft of each piece of rotating machinery to allow for torque measurements by the power produced or consumed by each component was calculated. Pressure transducers and thermocouples were located between each component in the system, flow in the liquid loops and gas loop were measured, and temperatures and flow rates of coolant flows were measured.
Approximately seventy tests were run with the experimental system under a number of conditions. The flooding liquid and compression fluid used in the experiments were alkyl-benzene oil and nitrogen, respectively, and the system was operated to evaluate C ratio values of about 3.5, 5, 10, and 15. Volumetric capacities of over 110 kJ/m 3 were measured. Though the best second law efficiency was a little over 3%, the low performance for the experimental system was anticipated due to a number of factors, including the large physical size of the system compared to its cooling capacity, and various sources of pressure drops. Details of the results of the experiments are reported in Hugenroth et al., “Liquid-Flooded Ericsson Cycle Cooler: Part 2-Experimental Results,” Proceedings of the 2006 International Refrigeration and Air Conditioning Conference at Purdue, R169, the contents of which are incorporated herein by reference.
From the above, it was concluded that scroll compressors could tolerate the necessary amount of liquid flooding required for operation of a reverse Ericsson cycle according to the present invention. In addition, it was concluded that the scroll-type compressor and expander operated reliably under the flooding conditions, and that the adiabatic efficiency of both the compressor and expander were very satisfactory.
While the invention has been described in terms of specific embodiments, it is apparent that other forms could be adopted by one skilled in the art. For example, the physical configuration of the thermodynamic systems could differ from that shown in the Figures, and materials and processes other than those noted could be use. Therefore, the scope of the invention is to be limited only by the following claims. | A thermodynamic system that can approximate the Ericsson or Brayton cycles and operated in reverse or forward modes to implement a cooler or engine, respectively. The thermodynamic system includes a device for compressing a first fluid stream containing a first gas-liquid mixture having a sufficient liquid content so that compression of the gas within the first gas-liquid mixture by the compressing device is nearly isothermal, and a device for expanding a second fluid stream containing a second gas-liquid mixture having a sufficient liquid content so that expansion of the gas within the second gas-liquid mixture by the expanding device is nearly isothermal. A heat sink is in thermal communication with at least the liquid of the first gas-liquid mixture for transferring heat therefrom, and a heat source is in thermal communication with at least the liquid of the second gas-liquid mixture for transferring heat thereto. A device is provided for transferring heat between at least the gas of the first gas-liquid mixture after the first fluid stream exits the compressing device and at least the gas of the second gas-liquid mixture after the second fluid stream exits the expanding device. The compressing and expanding devices are not liquid-ring compressors or expanders, but instead are devices that tolerate liquid flooding, such as scroll-type compressors and expanders. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of copending application Ser. No. 07/830,609 filed Feb. 4, 1992 pending for a "Mechanically Activated Skate Brake and Method."
FIELD OF THE INVENTION
This invention relates to roller skate brakes, and more particularly to a roller skate brake which is mechanically activated and stops the skate by applying friction to the ground rather than to a wheel of the skate. The invention has particular utility for use with "inline" skates and other modern skates that attain high speeds and are used in areas with pedestrians, automobiles and other hazards.
BACKGROUND OF THE INVENTION
Traditional roller skates, having sets of wheels in tandem, have long been used in the relatively controlled environment of a skating rink. In a skating rink, the skating surface is typically flat and smooth, skaters travel in the same direction around an oval or circular track, and there are few unexpected hazards. There has been, therefore, little need for an effective brake on a traditional roller skate.
Relatively recently, a faster and more maneuverable type of roller skate has been introduced. These skates, known as "inline" skates because the wheels are mounted in a line rather than in tandem, act much as an ice skate. Inline skates are offered in the United States by several vendors, including Rollerblade, Veraflex, Bauer, California Pro, and Hyper Wheels. Inline skates have appealed to the athletic adult and young adult, and to persons who enjoy the outdoors. Such skates are commonly used outside, on uneven sidewalks, bicycle paths, and roads. Skaters can achieve high speeds and can become a hazard to themselves and others when skating more rapidly than conditions allow. There is a need for an effective brake for inline skating to become a sport that is safe as well as enjoyable.
A brake commonly used on inline skates involves a fixed friction pad that extends behind the heel of the skate. The fixed friction pad is disposed above the skating surface and is made to swing down towards the skating surface by the skater's pivoting the skate about the axis of the rear wheel. As the skater does so, raising the toe of the skate and rotating the heel downward, the friction pad behind the heel will contact the ground and stop the skate. Such systems have also been used on tandem wheeled skates, and, because the speeds are not so high, can involve a fixed friction pad that extends in front of the toe of the skate. In this case, the skater brings the friction pad to bear on the skating surface by raising the heel and lowering the toe.
Examples of these physically activated (toe-raised, or toe-lowered) brakes include those described in U.S. Pat. Nos. 2,901,259 (tandem wheeled skates, brake member in the toe section, braking performed by lowering the toe); 4,313,610 of Volk (a friction-damped wheel in the heel section, braking performed by raising the toe); 4,865,342 of Kong (for a skate board). The adaptation of such a brake for use with an inline skate is shown in U.S. Pat. Nos. 4,394,028 of Wheelwright; 4,418,929 of Gray; 4,909,523 of Olson; 5,052,701 of Olson; and 5,067,736 of Olson.
Disadvantages of the physically activated, toe-raised (or lowered), brakes include these: (a) the braking maneuver requires the exercise of thigh muscle strength, and a skater's fatigue will make the maneuver more difficult to perform, (b) the braking maneuver requires the skater to place himself or herself in an awkward position, and a skater's lack of dexterity or balance will make the maneuver difficult to perform, especially if the skater is moving at relatively high speed or encounters an unexpected hazard, and (c) such brakes can only be used on one skate, effectively halving the potential stopping force available.
It may be said, in general, that an inexperienced skater finds it very intimidating to move his or her foot through such a large arc that he or she must jeopardize their balance in order to apply the brake. This has made many potentially new skaters reluctant to take up the sport at all.
There has been much interest in attempting to solve the problems of toe-raised (or lowered) brakes so as to make inline skating a sport that can be enjoyed by other than the young, the fit, or the reckless. Current attempts to do so have been directed towards replacing the physically-activated brake with a mechanically activated device. There have been attempts to mount a caliper or disc brake adjacent to the side or tread of one of the wheels of the skate. A hand lever-and-cable system can be used by the skater to apply friction pressure to the side or to the tread of the wheel, and the skate can be made to stop without the need for special body movement by a skater.
Examples of these mechanically activated (wheel based) brakes include those described in U.S. Pat. Nos. 4,295,547 of Dungan; 4,312,514 of Horowitz et al.; 4,943,075 of Gates; and 4,943,072 of Henig.
Disadvantages of trying to use the wheel of an inline skate for stopping include these: (a) the amount of contact that a wheel can have with the skating surface is very small when compared to the amount of contact that a friction pad behind the skate could have, (b) because inline skate wheels encounter considerable wear, and the wear is uneven, it is possible that the wheel selected for braking may have little, or no, contact with the ground, (c) heat generated by the rubbing of a brake pad on the wheel may cause the wheel to break down and fall apart, (d) the wheel selected for braking may develop flat spots and cause rough skating, and (e) the replacement cost of a skate wheel is high compared to the cost of replacing a friction pad behind the skate.
Thus, there are two general kinds of brake systems currently available. The first kind of brake stops the skate by using a physical maneuver to bring a pad into contact with the skating surface (toe-raised or toe-lowered brakes). The second kind of brake stops the skate by using a mechanically activated device to bring a pad into contact with a wheel of the skate (wheel-based brakes).
There are also some composite brakes, in which a physical maneuver is used both to bring a pad into contact with the skating surface and to bring another pad into contact with a wheel of the skate. Examples are described in U.S. Pat. No. 4,807,893 of Huang (brake member in the heel section, braking performed by depressing the heel); and in U.S. Pat. No. 4,453,726 of Ziegler. Composite brakes of this kind still fall into the general category of toe-raised or toe-lowered brakes and share all of the previously discussed disadvantages of the physically activated brake.
Despite the work which has been done to develop an optimum inline skate brake, each of the existing brakes has problems. Either they are hard to use (that is, the physically activated, toe-raised or toe-lowered brakes), or they offer relatively small effective stopping force (that is, the mechanically activated, wheel-based brakes). Accordingly, it can be seen that there is a need for an inline skate brake that better meets the needs of a skater.
The desired inline skate brake should have a relatively large effective area in contact with the skating surface so as to maximize the effective stopping power of the brake. In addition, the desired inline skate brake should permit an independent selection of the material for the portion that is in effective contact with the skating surface. That is, this important portion of the brake assembly should be selected without regard to factors other than its effectiveness (durability, coefficient of friction, and so on) for stopping the skate. These concerns suggest that the desired brake will not be a wheel-based brake in which the only area in contact with the ground is the wheel and in which the material in effective contact with the ground must be the same material as is used in the wheel itself.
The desired inline skate brake should be capable of being fitted to both skates, rather to just one skate, so as to double the effective braking surface area in contact with the skating surface. In addition, the desired inline skate brake should use the skater's hand, rather than his or her foot or leg, to activate the movement of the braking pad. Using the hand to activate the brake will allow the skater to use his or her total body, including hands, to maintain good balance at all times, including times when the skater needs to slow down or stop and when the need for balance may be greatest. These concerns suggest that the desired brake will not be a toe-raised or toe-lowered brake.
In addition, the desired inline skate brake should be capable of being retrofitted to most existing skates and should be capable of being installed as original equipment by skate manufacturers at reasonable cost. If the skate brake is mechanically activated, it should have a secondary, or "emergency," brake that can be used in the event of mechanical failure of the primary activator. If a cable-and-hand-lever activator is used, it should have some means for conveniently retaining the cables and hand levers.
It is a specific object of the current invention to provide a brake system that is mechanically activated, that uses the skating surface (rather than a wheel of the skate) for generating stopping force while the angle of the skate relative to the ground remains constant, that has a large effective area in contact with the skating surface, that can be fitted to both skates, that allows for an independent selection of the material in contact with the braking surface, that incorporates an emergency brake, that can be readily installed in new or used skates, and that conveniently retains all cables and hand-levers which are a part of the system. These, and other advantages, of the brake system of this invention will become apparent in the remainder of this disclosure.
U.S. patent application Ser. No. 07/830,609 (of which this is a continuation-in-part) discloses a hand-activated brake system having a rocker arm that accomplishes the foregoing objects. The present invention discloses two other hand-activated brake systems: one that includes a wrap around brake carriage; and another that includes a plunger.
Although this disclosure is directed towards the newer "inline" skates, it should be understood that the brake system of this invention may be readily adapted to the traditional tandem skates, skate boards, ski skates, and to other skating devices.
SUMMARY OF THE INVENTION
In a first embodiment, the skate brake system of this invention includes a carriage that pivots about the rear of a skate so as to bring a brake pad into contact with the skating surface when the carriage is activated. The carriage is hand-activated so that the skater need not perform any special body movement so as to raise (or lower) the toe of the skate. Accordingly, the angle of the skate relative to the ground remains constant while the brake is applied.
In the first embodiment, a Unshaped brake carriage wraps around the heel of a skate, with the heel of the U being oriented to the rear so that a brake pad may be brought into contact with the skating surface behind the skate when the carriage is activated.
The open end of the Unshaped carriage faces towards the front of the skate, and the closed end extends outwards behind the heel of the skate. In a preferred embodiment (for easy retrofit to existing skates) the brake carriage is pivotably connected to the axle of the rearmost wheel of the skate. A pair of holes from one arm to the opposite point on the other arm of the U is adapted so that the brake carriage may be mounted on the axle of the wheel.
A brake pad is mounted on the brake carriage behind the heel of the skate. In a preferred embodiment, the brake pad is contained within the cup of the "U" and is secured by a bolt embedded in the brake pad that is attached by a nut to a mounting piece within the carriage. The pad is further secured to the carriage by a set of complementary nipples and holes disposed in the mounting piece and the brake pad. When the brake is activated, the brake pad will swing down with the brake carriage until the pad hits the ground. When not activated, the brake pad will ride with the brake carriage above the skating surface. The brake pad is formed of a high density molded material having a high coefficient of friction and high durability.
The arms of the brake carriage act as levers about the pivot point. A first force applied to an arm causes the brake carriage to rotate about the axle of the wheel in a counterclockwise direction and drives the brake pad against the ground. A second force applied to an arm causes the brake carriage to rotate about the axle in a clockwise direction and pulls the brake pad away from the ground. A mechanical advantage may be obtained by mounting a pulley on the axle of the wheel and threading a cable around the pulley.
In a second embodiment, the skate brake system of this invention includes a plunger cannister mounted on a skate and containing a plunger that moves so as to bring the brake pad into contact with the skating surface when the plunger is activated. When the plunger cannister is oriented so that the plunger axis is substantially vertical relative to the skating surface, a brake pad connected to the plunger will contact the skating surface as the plunger is lowered. Thus, in a way analogous to the first embodiment, a first force applied to the plunger lowers it and drives the brake pad against the ground. A second force applied to the plunger lifts it and pulls the brake pad away from the ground.
The brake system of this invention (whether embodied as a carriage or as a plunger) is mechanically activated by hand so that the skater need not perform any special body movement so as to raise (or lower) the toe of the skate. In both embodiments, a cable-and-lever system may be used to provide the first force that drives the brake pad to the ground for stopping, and a spring may be used to provide the second force for holding the brake pad away from the ground for free skating. Where a cable is used, it becomes important to retain the cable, and this invention includes a housing that can be worn by the skater as a belt.
The belt includes elastic retainers that hold the cables, and also VELCRO-brand hook and loop fasteners. The elastic retainers are intended to help guard against the cables' dragging behind the skater if the cables should be dropped. The VELCRO-brand fasteners are intended to be used with complementary fasteners on the hand-operated levers so that the skater may conveniently affix the hand levers to the belt until needed.
The skate brake system of this invention may be used on either skate (left or right). It may also be used on both skates. When affixed to either skate, the skate brake system of this invention provides an effective surface area for the application of stopping force to the ground which is equal to or greater than that of typical toe-raised brakes, and which is substantially greater than typical wheel-based brakes. When affixed to both skates, the skate brake system of this invention can effectively double, or more than double, the stopping surface area of typical toe-raised brakes, and far exceeds the stopping surface area of the typical wheel-based brake.
Additional features of the skate brake system of this invention include an arresting assembly which acts as a secondary, or emergency, brake which can be used if the cable-and-lever actuator fails. The emergency brake includes an arresting bar oriented above the brake carriage in such a way that the system of this invention will lock in place, and may be used as a typical "toe-raised" brake. Other features, advantages, and mechanisms for activating the brake, including a thin wire activator, and a wireless activator that dispenses with cables altogether, and a method of using and installing this brake system, will be described in the detailed discussion that follows.
In summary, the brake system of this invention is mechanically hand-activated, uses the skating surface (rather than a wheel of the skate) for generating stopping force while the angle of the skate relative to the ground remains constant, has a large effective area in contact with the skating surface, can be fitted to both skates, allows for an independent selection of the material in contact with the braking surface, incorporates an emergency brake, can be readily installed in new or used skates, and conveniently retains all cables and hand-levers which are a part of the system. These, and other advantages, of the brake system of this invention will become apparent in the remainder of this disclosure.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the brake carriage assembly of this invention.
FIG. 2 is a top plan view of the brake carriage assembly of this invention.
FIG. 3 is a top plan view of a brake pad used in this invention.
FIG. 4 is a side elevational view of the brake carriage assembly of this invention, showing the brake pad mounted therein.
FIG. 5 is a perspective view of a belt for housing the hand-held controller(s) used to activate the brake system of this invention.
FIG. 6 is a side elevational, partially cut away view of the plunger cannister system of this invention.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
With reference to FIG. 1, it can be seen in overview that a first embodiment of the brake system of this invention includes a brake carriage 20, a brake pad 40, an actuator support arm 60, and an actuator assembly 80. Each of these elements will be discussed individually, before returning to FIG. 1 for a discussion of the elements in combination.
Referring to FIG. 2, it can be seen that the brake carriage 20 of this invention is a "U" shaped frame having a first arm 22, a second arm 24, a back frame member 26, and a brake mounting piece 28.
It can be seen that the brake carriage 20 is set behind the skate. In this embodiment, the carriage 20 is oriented so that it may wrap around the back of the skate. The brake carriage 20 is pivotally attached to the axle 18 of a wheel 14 of a skate, and held in place by the axle nuts 16. A pulley 84 is mounted on axle 18, and a retaining pin 86 is mounted on carriage arm 22.
The brake mounting piece 28 of the brake carriage 20 has four holes 32 which serve to retain the brake pad (not shown in FIG. 2). A nut 33 is shown above a hole 34, and serves to affix the brake pad (not shown).
With reference to FIG. 3, it can be seen that the brake pad 40 has four nipples 42 protruding from its top surface, and has an embedded bolt 44. Looking at FIG. 4, it can be understood that the brake pad 40 fits securely into the brake carriage 20 within the cup formed at the base of the "U". It can be seen that the embedded bolt 44 of the brake pad 40 passes through the hole 34 (not separately numbered in FIG. 4) of the brake mounting piece 28 and is attached to the mounting piece 28 by bolt 33. The nipples 42 of the brake pad 40 pass through the holes 32 (not separately numbered in FIG. 4) of the brake mounting piece 28 and further secure the brake pad 40 in place. In FIG. 4, it may also be seen that the embedded bolt 44 of the brake pad has a head 46 having flanges 48. The flanges 48 serve to secure the bolt 44 within the brake pad 40.
Returning to FIG. 1, it can now be seen that the brake carriage 20 is pivotably attached behind the heel of an inline skate boot 10. A typical inline skate, as shown in FIG. 1, includes a skate boot 10 having a wheel housing 12 in which several wheels 14 are mounted. Each wheel 14 is affixed by a nut 16 to an axle 18. The brake carriage 20 pivots about the axle 18 of the rearmost wheel 14.
The brake carriage 20 carries the brake pad 40, and the brake carriage 20 is slipped onto the axle 18 of the wheel 14 over the actuator support arm 60. The brake carriage 20 is operatively connected to the actuator assembly 80. In this embodiment, the actuator assembly includes a cable 82 having a linkage carried in an actuator housing 62 of the actuator support arm 60, and a pulley 84 mounted on the axle 18.
Arm 22 of the brake carriage 20 is connected to cable 82 of the actuator assembly 80 at retaining pin 86. Retaining pin 86 is located along the arm as shown. Cable 82 runs from the retaining pin, around pulley 84, and to the linkage carried in actuator housing 62.
It can be understood that, when the actuator assembly 80 is engaged so as to pull the cable 82 towards the actuator housing 62, the resultant force will pull the carriage arm 22 towards the periphery of pulley 84. This, in turn, will cause the brake carriage assembly 20 to rotate in a counter-clockwise direction about the pivot axle 18 of the rearmost wheel 14. This rotation will urge the brake pad 40 towards the ground where it will engage the skating surface to stop the skate.
A tension spring 88 is attached, at one end, to arm 22 of the brake carriage and, at the other end, near actuator housing 62 of the actuator support arm 60. Thus, when the cable 82 is not engaged, the spring tension will pull carriage arm 22 towards actuator housing 62. This, in turn, will cause the brake carriage assembly 20 to rotate in a clockwise direction about the pivot axle 18 of the rearmost wheel 14. This rotation will urge the brake pad 40 away from the ground where it will ride until activated by the actuator assembly 80.
It should be readily understood that the responsiveness of the brake system is influenced by the location of retaining point 86 on the arm in relation to pivot axle 18, which is the pivot point about which the arm rotates. If desired, the responsiveness of the brake system may be further influenced by fixing a retaining pin even further away from pivot axle 18. As will be described below, one way to do so is by using a separate mounting assembly to extend the retaining pin beyond arm 22.
Shown in phantom in FIG. 1 is a mounting assembly 90 set on top of carriage 20. It can be understood that retaining pin 86 could be removed and that cable 82 could be extended so as to reach the mounting assembly. With reference to the phantomed structure shown in FIG. 1, it may be seen that the cable could be secured to mounting assembly 90 at a retaining pin 92, and a tension spring 94 could be set between the mounting assembly 90 and actuator support arm 60. By adjusting the location of the retaining pin in relation to the axis of rotation 18, including placement of the retaining pin above the brake carriage, the retaining pin is extended beyond arm 22 and the responsiveness of the brake system may be tuned as desired.
The arresting arm 64 of the actuator support arm 60 can now be understood to operate as an emergency brake. In the event that some component of the actuator assembly 80 should fail, the system of this invention uses the arresting arm 64 to simulate the working of a traditional toe-raised brake. It can be seen that the arresting arm 64 extends outward from the actuator support arm 60. In an emergency situation, the skater may lift the toe of the skate, bringing the brake pad 40 into contact with the ground. This maneuver is performed by the skater pivoting rearwardly about the axis of the rear skate wheel and swinging the skate from the normal coasting position to a braking position where the brake pad 40 drags against the ground. Although carriage arm 22 of the brake carriage 20 will pivot, the arresting arm 64 will limit the arcuate range of rotation, and will lock the rocker arm in place at the limit of rotation. Locked into place, the rocker arm 22 holds the brake pad 40 against the skating surface so that the brake pad will drag against the ground and bring the is skater to a stop.
Finally, although the brake system as shown discloses an actuator assembly that includes a pulley 84 to obtain a mechanical advantage, it should be understood that the brake system of this invention may be operated with any number of well known equivalent structures, all serving to transmit force to carriage 20 so as to rotate the carriage about a pivot axis.
The actuator assembly is activated by a hand-held controller 90 (reference FIG. 5). To better accommodate the needs of a skater, this invention includes a VELCRO-brand hook and loop fastener 92 affixed to the controller 90, and a corresponding VELCRO-brand hook and loop fastener 94 which is placed on a belt 96. It can be seen that the skater may, when not holding the controller 90, readily place it on the belt 96 by the VELCRO-brand hook and loop fastenings.
For further convenience, and safety, the controller 90 is attached to the belt 96 by a strap 98. Strap 98 is designed to aid the skater in the event that the skater should drop the controller 90. Instead of dragging behind the skater on the ground, the controller 90 is retained by strap 98. The strap 98 may be made of elastic material in order that it may be relatively short (so that the controller 90 will be within reach if dropped) but also able to travel at arm's length (so that the skater will be able to hold the controller 90 at a comfortable distance from the body).
Materials and dimensions suitable for producing this embodiment of the brake system of this invention include these:
The brake carriage 20, as shown in FIG. 2, may be of cast steel, aluminum, or a high density polymer; the back frame member 26 is about 2.0 inches in length; carriage arms 22 and 24 are about 3.0 inches in length.
The brake pad 40 may be molded polyurethane, and dimensioned so that the bottom surface is about 1.5 inches by about 2.25 inches so as to provide a stopping surface of about 3.375 square inches. The embedded bolt 44 may be 0.25 inch-20 having 1.0 inch length with a 31/32 inch bolt head.
The actuator assembly 80 may include a cable housing having an outer diameter of about 5.0 mm, and an inner diameter of about 2.0 mm. The cable housing may be of coiled steel with vinyl covering and a TEFLON liner. The cable 82 has a diameter of slightly less than 2.0 mm and may be made of wound steel.
Second Embodiment
With reference to FIG. 6, it can be seen in overview that a second embodiment of the brake system of this invention includes a plunger cannister 120, a brake pad 40, an actuator support arm 60, and an actuator assembly 80 (for ease of reference, structures which are common to the first and second embodiment will be designated with identical numerals). Moreover, many of the workings of the second embodiment are the same as the first embodiment and will not be repeated here in detail.
The plunger cannister 120 houses a plunger 122 having a top surface 124 and a bottom surface 126 joined together by a plunger wall 128. In a preferred embodiment, plunger 122 is channelled and hollowed in order to accommodate cable 82 and pulley 130 in the interior of the plunger, but it should be understood that the plunger may be constructed many other ways, including by fabricating an open frame that joins the top and bottom surfaces.
The plunger cannister is mounted to the rear of the skate and is oriented so that the plunger axis is vertical relative to the skating surface. In this embodiment, the cannister 120 is mounted to a support 132 which wraps around the rear of the skate. Support 132 is secured to the skate at the axle 18 of the rearmost wheel 14, and is further secured by bolt 134.
The brake pad 40 is fixed to the bottom surface 126 of plunger 122. The bottom surface 126 works as does the brake mounting plate 28 already discussed with reference to the first embodiment. Bottom surface 126 and brake pad 40 may include the bolt, nipples, holes and other structures previously discussed, with such adaptations as would be easily understood by one skilled in the art to secure the attachment of brake pad to bottom surface of the plunger.
The plunger cannister 120 is operatively connected to the actuator assembly 80. In this embodiment, the actuator assembly includes a cable 82 having a linkage carried in an actuator housing 62 of the actuator support arm 60, and a pulley 84 mounted on the axle 18.
Plunger 122 is connected to cable 82 of the actuator assembly 80 at retaining pin 136. Cable 82 runs from the retaining pin, around pulleys 130 and 84, and to the linkage carried in actuator housing 62.
It can be understood that, when the actuator assembly 80 is engaged so as to pull the cable 82 towards the actuator housing 62, the resultant force will pull the plunger 122 downwards towards the skating surface. This movement will urge the brake pad 40 towards the ground where it will engage the skating surface to stop the skate.
A tension spring 138 is attached, at one end, to the top surface 124 of the plunger and, at the other end, to the plunger cannister 120 near the top of the cannister. Thus, when the cable 82 is not engaged, the spring tension will pull the plunger upwards. This tension will urge the brake pad 40 away from the ground where it will ride until activated by the actuator assembly 80.
An arresting bead 140 within the plunger cannister 120 can now be understood to operate as an emergency brake. In the event that some component of the actuator assembly 80 should fail, the system of this invention uses the arresting bead 140 to simulate the working of a traditional toe-raised brake. It can be seen that the arresting bead 140 extends inward from the interior wall of the cannister 120.
In an emergency situation, the skater may lift the toe of the skate, bringing the brake pad 40 into contact with the ground. This maneuver is performed by the skater pivoting rearwardly about the axis of the rear skate wheel and swinging the skate from the normal coasting position to a braking position where the brake pad 40 drags against the ground. Although plunger 122 will be pushed upwards, the arresting bead 140 will contact the outer lip of the bottom surface 126 of the plunger so as to limit the range of movement, and will lock the plunger in place at the limit of movement. Locked into place, the cannister 120 holds the brake pad 40 against the skating surface so that the brake pad will drag against the ground and bring the skater to a stop.
The plunger cannister and plunger assembly just described use a direct pull to bring the plunger down towards the skating surface. It should be readily understood that other, equivalent mechanisms may also be used, including mechanisms using levers and like devices to gain a further mechanical advantage.
Method of Use
The method of use of the brake system of this invention will now be explained. The method includes using a brake carriage or plunger to stop the skate, with the carriage or plunger being hand-activated by a mechanical device so as to bring a brake pad that is operatively connected to the carriage or plunger into contact with the skating surface. This method permits the skater to activate the brake without changing the angle of the skate itself relative to the ground--that is, the skater need not lift or lower the heel or toe of the skate. This method also permits the brake pad to contact the skating surface rather than the wheel of the skate.
The method of this invention further includes the option of using two brakes, one on each skate, and includes using hook and loop devices, and straps, to secure the hand controls needed to activate the brake. An emergency braking method involves lifting the toe of the skate, using an arresting bar to lock the carriage, or an arresting bead to lock the plunger, so that the skate may then be stopped like a traditional toe-raised brake. All of the various components necessary to carry out this method have already been explained.
The system of this invention also includes a method for retrofitting the brake to an existing skate. This retrofit method includes removing the axle bolts from the rear wheel of an existing skate; placing the pivot point of a brake carriage, or a plunger cannister support, over the axle; and then replacing the axle bolts so as to secure the structure in place. Optionally, an actuator support arm, or equivalent activating structure, may also be secured to the existing skate.
The foregoing description is addressed to two preferred embodiments. It should be apparent to one skilled in the art that numerous changes and adaptations may be made.
It should also be apparent that the actuator need not be a cable-and-lever device. Because the cable can be seen as a drawback, it might be replaced by (a) a wireless electromechanical actuator, (b) a thin-wire electromechanical actuator.
In the wireless form (not separately shown), a radio-controlled method of activation is used. With reference to FIGS. I and 6, it may be understood that a signal may be sent to a solenoid carried at the actuator housing 62 to activate the cable 82. A transmitter may be carried in the skater's hand or on the waist with a battery pack attached to the skate, and the signal to activate the solenoid is sent from the transmitter. The solenoid (and equivalent wireless controllers) is well known to persons skilled in the art, and will not be further described here.
Finally, in the thin-wire form (not separately shown), a transmitter and power source are attached to the skater's waist and a wire runs from the power source to a servomechanism on the skate which activates the cable 82.
In summary, the brake system of this invention is mechanically activated, uses the skating surface (rather than a wheel of the skate) for generating stopping force while the angle of the skate relative to the ground remains constant, has a large effective area in contact with the skating surface, can be fitted to both skates, allows for an independent selection of the material in contact with the braking surface, incorporates an emergency brake, can be readily installed in new or used skates, and conveniently retains all cables and hand-levers which are a part of the system. | A skate brake system includes a carriage that pivots about the rear of a skate so as to bring a brake pad into contact with the skating surface when activated by a hand-activated actuator. The skater need not perform any special body movement to raise (or lower) the toe of the skate, and, accordingly, the angle of the skate relative to the ground remains constant while the brake is applied. In another embodiment, a plunger cannister contains a plunger that brings a brake pad into contact with the skating surface when the plunger is actuated by a hand-activated actuator. | 0 |
BACKGROUND OF THE INVENTION
This invention relates to vehicle tire parameter monitoring systems. More particularly, this invention relates to a fire parameter monitoring system having a sensor unit position location feature using permanent magnets.
Tire parameter monitoring systems are known and are commonly used to monitor one or more parameters of interest in individual pneumatic tires of a vehicle and to provide an advisory signal to the driver, usually via an on-board computer system, containing information about the fire parameter(s). The portion of the fire parameter monitoring system located at or in the individual fires is termed the sensor unit, and is coupled to one or more sensors capable of measuring the parameter(s) of interest and generating an electrical signal representative of the value of the measurement, a signal generator (typically an r.f. signal generator) capable of generating a wireless signal corresponding to the electrical signal, a microcontroller (such as a microprocessor or a digital signal processor) and a power source. Electrical power to the sensor circuitry is usually provided by a battery, which must be replaced (if possible) when the available battery power drops below a useful level. In some known systems, the battery cannot be replaced so that the entire sensor assembly must be replaced when the battery has reached the end of its useful lifetime. A tire parameter sensor system which monitors internal tire pressure is disclosed in commonly assigned, U.S. Pat. No. 6,959,594 issued Nov. 1, 2005 for “External Mount Tire Pressure Sensor System”, the disclosure of which is hereby incorporated by reference. A tire pressure monitoring system which incorporates a power saving unit providing extended useful battery life is disclosed in commonly assigned, U.S. Pat. No. 7,222,523 issued May 29, 2007 for “Tire Pressure Sensor System With Improved Sensitivity And Power Saving”, the disclosure of which is hereby incorporated by reference. A tire parameter monitoring system which eliminates the usual battery is disclosed in commonly-assigned, co-pending patent application Ser. No. 11/473,278 filed Jun. 22, 2006 for “Tire Parameter Monitoring System With Inductive Power Source” (the '278 application), the disclosure of which is hereby incorporated by reference.
The advisory signal produced by the sensor unit may indicate (a) whether a given parameter in the associated vehicle tire has a current value lying within or outside of a predetermined safe range, (b) the measured value of the parameter, or (c) some other fire parameter information of interest. Examples of common tire parameters are internal tire pressure, tire temperature, internal tire air temperature, and lateral tire force. In some cases, the parameter may be related to the condition of the wheel on which the tire is mounted, such as the angular moment of the wheel, concentricity or the like.
The advisory signal is typically generated by the r.f. signal generator controlled by the microprocessor connected to the tire parameter sensor, the advisory signal being generated in accordance with the system design characteristics: i.e., whether the system uses the range indicator value (in range/outside range), the measured value, or the other information of interest. This r.f. signal is transmitted to a vehicle-mounted receiver, which uses the advisory signal to alert the driver either visually (by activating a warning lamp or display) or audibly (by activating an audible alarm) or both. Alternatively, or in addition, the receiver may use the advisory signal for some other system purpose, such as to activate a vehicle control system, such as braking control, suspension control, and the like; to store the parameter data for future analysis; or for any other desired purpose.
In order to provide an operable system, it is necessary to correlate the advisory signals received by the vehicle-mounted receiver with the physical location on the vehicle of the tire whose parameter condition is specified by a given advisory signal. In the past, various techniques have been devised for this purpose. A common technique is the inclusion of an identification signal along with the parameter condition in a given advisory signal: the identification signal is unique to the sensor unit which generates the parameter condition. This unique identification signal is initially correlated to tire location on the vehicle by a technician having the required skill and training to operate the system in an initial training mode. Once each sensor unit has been initially correlated to its physical location on the vehicle, any advisory signal generated by a given sensor unit and received by the vehicle-mounted receiver can be uniquely identified with the location of the tire whose parameter condition is specified by the advisory signal.
A disadvantage with this type of location correlation technique is that any change to the original tire and sensor unit location requires that the system be re-correlated. For example, if the vehicle tires are relocated to different positions in the normal course of vehicle servicing, the physical locations of the sensor units will change if the sensor units are fixed to the tires or the wheels on which the tires are mounted (which is typical), and each individual sensor unit must be re-correlated to the physical location of the associated tire. The same is true (a) when a spare tire is exchanged for a flat tire on the vehicle; (b) when one or more new tires are installed on the vehicle wheels and mounted on the vehicle; and (c) when a new sensor unit is installed in place of a unit which stops functioning property. As noted above, re-correlation requires the efforts of someone having the required skill and training to operate the system in a training mode. While some vehicle owners may be capable of acquiring the necessary skill and training, others may not. The latter will necessarily suffer delay and expense when re-configuring the vehicle tires and wheels; the former will suffer at least the delay attendant upon re-familiarizing oneself with the steps required to re-program an electronic system.
A variation of this type of sensor unit correlation system uses a manually actuatable transmitter installed in the valve stem of a tire. The transmitter is actuated by inserting a small object into the valve stem a sufficient axial distance to operate a switch, which causes the transmitter to send an appropriate signal to a vehicle-mounted receiver capable of correlating the signal from the operating transmitter to the tire to which the transmitter is attached. An example of this type of system is disclosed in U.S. Pat. No. 6,998,975 B2 issued Feb. 14, 2006, the disclosure of which is hereby incorporated by reference. This system requires some provision for ensuring that any change to the original sensor unit/tire location configuration will cause a re-correlation of the sensor units with the new configuration.
Another common technique used to correlate the advisory signals received by the vehicle-mounted receiver with the physical location on the vehicle of the tire whose parameter condition is specified by a given advisory signal incorporates a special multiple antenna interrogator system connected to a vehicle-mounted controller and a complementary set of sensor units. Each antenna is connected to the controller in such a way that only one antenna is actively coupled to the controller during any given interrogation interval. Each antenna is located adjacent a different associated one of the sensor units in sufficiently close proximity that an interrogation signal generated by a given antenna is operatively coupled essentially only to the associated sensor unit. Each sensor unit has a circuit responsive to an interrogation signal from the associated antenna to initiate a parameter signal transmission sequence during which the value measured by a sensor is transmitted to a receiver located in the vehicle-mounted controller, where it is processed. Since the location of each individual interrogation antenna is fixed, it can be permanently correlated to a wheel location. Therefore, when the controller activates a given interrogation antenna, the subsequently received parameter signal is automatically correlated with the correct tire location. Examples of this type of unit are disclosed in U.S. Patent Application Publication No. US 2003/0145650 A1 published Aug. 7, 2003; and U.S. Pat. No. 6,838,985 B2, the disclosures of which are hereby incorporated by reference.
A disadvantage to the interrogator antenna system described above lies in the requirement for the installation of the separate interrogation antennae adjacent the tire parameter sensor units. The necessary electrical cabling must be routed between the controller and the individual antennae. This imposes a requirement of careful routing of the cables to avoid mechanical abrasion, electrical interference, and thermal stresses over time. As a consequence, installation cost and hardware durability are factors of concern when deciding to implement such a system.
Efforts to provide a simple, inexpensive, reliable, and accurate sensor unit location feature for a tire parameter sensing system devoid of the above-noted disadvantages have not been successful to date.
SUMMARY OF THE INVENTION
The invention comprises a method and system for providing sensor unit location information which is simple and inexpensive to implement, highly reliable, and accurate.
In a first apparatus aspect, the invention comprises a sensor unit for use with a vehicle mounted tire parameter monitoring system having at least one tire parameter sensor, the sensor unit including a magnetic sensing element for generating location signals from magnetic fields encountered by the magnetic sensing element; a microcontroller coupled to the magnetic sensing element for receiving and processing the location signals and tire parameter signals from an associated tire parameter sensor; and a signal generator controlled by the microcontroller for transmitting the processed location signals and the tire parameter signals to a receiving location. The magnetic sensing element of the sensor unit preferably comprises an inductive coil having an output coupled to an input of the microcontroller.
The sensor unit further preferably includes an analog-to-digital converter having an input coupled to the magnetic sensing element and an output coupled to the microcontroller for converting the analog location signals to digital form.
The sensor unit further includes one or more tire parameter sensors each having an output coupled to the microcontroller for supplying current values of the monitored tire parameters for processing by the microcontroller.
In a second apparatus aspect, the invention comprises a tire parameter monitoring system for monitoring the current values of tire parameters of tires mounted on a vehicle, the system comprising a plurality of sensor units each associated to a different tire on the vehicle, each sensor unit including a magnetic sensing element for generating location signals from magnetic fields encountered by the magnetic sensing element; a microcontroller coupled to the magnetic sensing element for receiving and processing the location signals and tire parameter signals from an associated tire parameter sensor; and a signal generator controlled by the microcontroller for transmitting the processed location signals and the tire parameter signals to a receiving location; and a plurality of sets of magnets for generating a plurality of different magnetic field signals, each set of magnets being located in proximity to a different one of the plurality of sensor units in a location at which the magnetic field generated thereby is encountered by the corresponding sensor unit as the associated tire rotates. Each magnetic sensing element preferably comprises an inductive coil.
Each sensor unit preferably includes an analog-to-digital converter having an input coupled to the magnetic sensing element and an output coupled to the microcontroller for converting analog location signals to digital form.
Each said sensor unit further preferably includes one or more tire parameter sensors each having an output coupled to the microcontroller for supplying current values of the monitored tire parameters for processing by the microcontroller.
The system further includes a receiver processor for receiving and processing the location signals and tire parameter signals from the sensor units.
From a process standpoint, the invention comprises a method of correlating tire parameter signals generated by sensor units associated to different ones of a plurality of tires on a vehicle with the location of tires whose parameters are monitored by the sensor units, the method comprising the steps of:
(a) generating a plurality of different magnetic field signals in proximity to the sensor units, each different magnetic field signal being associated to a different tire location on the vehicle; (b) converting each different magnetic field signal to an electric sensor unit location signal; (c) combining each electric sensor unit location signal with the tire parameter signals from the sensor unit at the location specified by the electric sensor unit sensor signal, and (d) transmitting the signals combined in step (c) to a receiving location.
Step (a) of generating preferably includes the step of using a plurality of sets of permanent magnets, each set being located in proximity to a different tire.
Step (b) of converting preferably includes the steps of moving a magnetic sensing element located on a given sensor unit through the proximate magnetic field signal.
Each electric sensor unit location signal is preferably an analog signal; and step (b) of converting preferably includes the step of converting the analog signal to a digital signal.
The method further preferably includes the step (e) of processing the signals transmitted in step (d) at the receiving location, and the step (e) of processing preferably includes the step of generating a driver advisory signal for a given tire parameter.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic top plan view of a tire parameter sensing system incorporating the sensor unit location feature of the invention;
FIG. 2 is a schematic side view showing one magnet pair mounting arrangement according to the invention;
FIG. 3 is a schematic front view showing a tire and wheel mounted in operative relation to the magnet mounting arrangement of FIG. 2 ;
FIG. 4 is a schematic perspective view showing another magnet pair mounting arrangement according to the invention;
FIG. 5 is a schematic front partial sectional view showing a tire and wheel mounted in operative relation to the magnet mounting arrangement of FIG. 4 ;
FIG. 6 is a schematic block diagram of a preferred embodiment of a sensor unit;
FIG. 7 is a compound diagram illustrating four different, unique magnetic polarity orientations and the corresponding associated electric waveforms;
FIG. 8 is a compound diagram illustrating a plurality of unique magnetic polarity orientations using three magnets and the corresponding eight associated electric waveforms.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, FIG. 1 is a schematic top plan view of a tire parameter sensing system incorporating the sensor unit location feature of the invention. As seen in this Fig., which illustrates a vehicle having four tires and wheels, each tire has an associated tire parameter sensor unit SU. Thus, left front tire 11 is provided with SU 12 ; right front tire 13 is provided with SU 14 ; left rear tire 15 is provided with SU 16 ; and right rear tire 17 is provided with SU 18 . As described more fully below in connection with FIG. 6 , each SU 12 , 14 , 16 , and 18 is connected to one or more tire parameter sensors for monitoring the state of individual tire parameters, such as internal tire pressure, tire temperature, internal tire air temperature, and lateral tire force. Such sensors are well known in the art and will not be described further to avoid prolixity. The physical location of the individual SUs 12 , 14 , 16 , and 18 is a matter of design choice and may include the outer side wall of the associated tire, the inner side wall of the tire, within the tire carcass at an appropriate location (such as within the inner side wall of the tire as illustrated in FIG. 3 or within the tread wall of the tire as illustrated in FIG. 5 ), or on the wheel hub. Each SU 12 , 14 , 16 , and 18 further incorporates a magnetic field sensing element for a purpose to be described. Each SU 12 , 14 , 16 , and 18 also incorporates a microcontroller unit for processing sensor signals and magnetic field signals, and an r.f. transmitter unit for transmitting tire parameter advisory signals and magnetic field signals to a central receiver/processor 25 . Central receiver/processor 25 uses the magnetic field signals to associate the tire parameter advisory signals with the correct tire, and converts the tire parameter advisory signals into driving signals for a display/alarm unit 26 of conventional design, in which the parameter states can be displayed for the user and in which audible alarm signals can be generated to alert the driver of a dangerous tire condition.
FIGS. 2 and 3 illustrate one magnet pair mounting arrangement used in conjunction with SUs 12 , 14 , 16 , and 18 to provide sensor unit location signals according to the invention. FIG. 2 is a schematic side view showing the magnet pair mounting arrangement, while FIG. 3 is a schematic front view showing a tire and wheel mounted in operative relation to the magnet mounting arrangement of FIG. 2 . With reference to FIG. 2 , a pair of permanent magnets 31 , 32 is secured to a suspension component 34 at a location adjacent a wheel mounting hub 35 . Magnets 31 , 32 are thus stationary with respect to the wheel and tire when the wheel and tire are rotating. The exact location of magnets 31 , 32 is a function of the geometry of the wheel and tire and the location of the sensor unit. As seen in FIG. 3 , which illustrates the left front tire 11 viewed from the rear and looking forward, for a sensor unit 12 mounted within the side wall of tire 11 , magnets 31 , 32 are mounted on suspension unit 34 in a location at which the combined magnetic fields will encounter the magnetic field sensing element incorporated into sensor unit 12 . Thus, whenever tire 11 is rotating, sensor unit 12 will encounter the combined magnetic field from magnets 31 , 32 once per tire revolution.
FIGS. 4 and 5 illustrate another magnet pair mounting arrangement used in conjunction with SUs 12 , 14 , 16 , and 18 to provide sensor unit location signals according to the invention. This arrangement is used in those installations in which the sensor unit is mounted in the tread wall of the tire. FIG. 4 is a schematic perspective view showing this magnet pair mounting arrangement, while FIG. 5 is a schematic front view partially in section showing a tire and wheel mounted in operative relation to the magnet mounting arrangement of FIG. 4 . With reference to FIG. 4 , a pair of permanent magnets 31 , 32 is secured to a mechanical component 37 (such as a fender) at a location adjacent the upper surface of the tire tread wall 38 . Magnets 31 , 32 are thus stationary with respect to the wheel and tire when the wheel and tire are rotating. The exact location of magnets 31 , 32 is a function of the geometry of the wheel and tire and the location of the sensor unit. As seen in FIG. 5 , which illustrates the left front tire 11 viewed from the rear and looking forward, for a sensor unit 12 mounted within the tread wall 38 of tire 11 , magnets 31 , 32 are mounted on mechanical component 37 at a location at which the combined magnetic fields will encounter the magnetic field sensing element incorporated into sensor unit 12 . Thus, whenever tire 11 is rotating, sensor unit 12 will encounter the combined magnetic field from magnets 31 , 32 once per tire revolution.
FIG. 6 is a schematic block diagram of a preferred embodiment of a sensor unit SU. As seen in this Fig., a magnetic field sensing element 41 , illustrated as a multi-turn coil, is ohmically connected to two different circuit paths. The upper path comprises an analog-to-digital converter 42 having a pair of input terminals to which the output of magnetic field sensing element 41 is connected. The output of analog-to-digital converter 42 is connected to an input of a microcomputer unit 43 . The lower path comprises a rectifier circuit 45 having a pair of input terminals to which the output of magnetic field sensing element 41 is connected. The output of rectifier circuit 45 is connected to a D.C. power regulator circuit 46 . Elements 45 , 46 function to develop D.C. power from the electrical current developed in coil 41 from passing through the magnetic field produced by magnets 31 , 32 once per revolution of the associated tire. This process is more fully described in the afore-mentioned '278 application.
One or more tire parameter sensors 47 supply tire parameter electrical signals representative of the value of the sensor measurement(s) to the microcomputer unit 43 . Microcomputer unit 43 combines these signals with the digital version of the magnetic field sensing element 41 signals and supplies these to an r.f. generator 48 . R.f. generator 48 converts the received signals and transmits the converted signals to central receiver processor 25 , in which the received signals are processed and used to drive display/alarm unit 26 . Since the received signals contain the magnetic field identification signals, the accompanying tire parameter measurement signals are correlated to the magnetic field identification signals. The microcomputer unit 43 and r.f. generator 48 are preferably combined in a commercially available Freescale type MC68HC908RF2 unit or the equivalent, having a transmitter section for generating r.f. information signals containing tire parameter measurement results and magnetic field sensing element signals, and a microcomputer for supervising and controlling the operation of the transmitter section and for sensing the analog-to-digital converter 42 signals and the sensor output signals and converting these sampled signals to measurement data to be supplied to the transmitter section.
FIG. 7 is a compound diagram illustrating four different, unique magnetic polarity orientations and the corresponding associated electric waveforms which uniquely identify the location of a given sensor unit 12 , 14 , 16 , 18 . As seen in this Fig., magnets 31 , 32 can be arranged in four different and unique magnetic polarity orientations: NS, SN, SS, and NN. In this Fig., the legend N signifies that the north pole of the magnetic field generated by a magnet faces the viewer and the south pole is located at the hidden reverse surface of the magnet; while the legend S signifies that the south pole of the magnetic field generated by a magnet faces the viewer and the north pole is located at the hidden reverse surface of the magnet. When magnetic field sensing element 41 passes through the compound magnetic field produced by a given combination of magnets 31 , 32 , the resulting induced analog electrical signal has a unique shape as illustrated for the four different magnetic orientations. Each unique shape is permanently assigned to a tire location on the vehicle. In the example illustrated in FIG. 7 , the uppermost signal shape is assigned to the front right tire location; the next signal shape is assigned to the front left tire location; the next signal shape is assigned to the rear right tire location; and the lowermost signal shape is assigned to the rear left tire location. As will be appreciated by those skilled in the art, the signal shape assignments are arbitrary: what is necessary is that the signal shape assignments be unique, invariant and programmed into the central receiver/processor 25 . In this way, any tire parameter measurement signals received by the central receiver/processor 25 can be correlated to the transmitting location by the accompanying magnetic field sensing element signals.
When installing a system according to the invention at the vehicle factory, the usual quality control procedures can readily assure that the orientation of magnets 31 , 32 conforms to the signal shape assignments for the fire locations, which are programmed into the central receiver/processor 25 . Similarly, when installing a system according to the invention as an aftermarket item, care need only be taken that the orientation of magnets 31 , 32 conforms to the signal shape assignments for the tire locations. Once installed, re-location of tires does not affect the accuracy and reliability of the system since the location of the sensor units is irrelevant to the identification of the location of the transmitting sensor unit. Thus, a spare tire can be exchanged for a tire on the vehicle without affecting the operation of the system.
While the preferred embodiment has been described with reference to vehicles having four running tires, the invention is not so limited. For vehicles having more than four running tires, additional magnets can be added at each location and the signal shape assignments can be altered accordingly to accommodate analog signals having three or more components. FIG. 8 illustrates a three magnet arrangement which can uniquely identify up to 8 individual tires. In general, for N magnets, the number of individual tires which can be uniquely identified is 2 exp N.
Further, although the sensor unit has been described above as including an inductive D.C. power generating section comprising rectifier circuit 45 and D.C. power regulation unit 46 , if desired this section may be omitted and some other D.C. power source—such as a battery—may be included. In such a configuration, the location signals and the sensor signals are processed in the same way as in the sensor unit described above.
As will now be apparent, the invention provides a tire parameter sensing system incorporating a sensor unit location feature which is simple and inexpensive to implement, highly reliable, and accurate. Installation of systems according to the invention can be readily done at the vehicle factory as an integral part of the manufacturing operation, or by aftermarket installers to retro-fit existing vehicles with the latest tire parameter monitoring technology. Once installed, tires can be re-located to other arbitrary locations without affecting the accuracy and reliability of the location information.
While the invention has been described with reference to particular preferred embodiments, various modifications, alternate embodiments, and equivalents may be employed, as desired. For example, other magnetic sensing elements, such as Hall effect sensors or MR sensors, may be employed in place of the simple multi-turn coil element, as desired. Therefore, the above should not be construed as limiting the invention, which is defined by the appended claims. | A tire parameter monitoring system has a plurality of sensor units each mounted with a different vehicle tire. Each sensor unit has a magnetic sensing element for converting magnetic field signals generated by a proximate set of magnets mounted to the vehicle at the tire locations. Each magnet set generates a unique magnetic field which identifies the magnet set location. Each sensor unit has a microcontroller for combining the converted magnetic field signals with fire parameter signals, and a transmitter for transmitting the combined signals to a receiving location. Received tire parameter signals are correlated with the tire location using the location signals, and driver advisory signals are presented to the driver. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application No. 12/622,501 filed Nov. 20, 2009, now U.S. Pat. No. 8,006,883, entitled “Fastener Driver Having Nosepiece Cover”, which is a divisional of U.S. patent application Ser. No. 11/050,280, filed Feb. 3, 2005, entitled “Magazine Assembly For Nailer”, now U.S. Pat. No. 7,641,089, which claims the benefit of U.S. Provisional Application No. 60/559,342, filed on Apr. 2, 2004, the disclosures of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a cordless nailer, and more particularly to a magazine assembly for a cordless nailer.
BACKGROUND OF THE INVENTION
Fastening tools, such as power nailers and staplers, are relatively commonplace in the construction trades. Often times, however, the fastening tools that are available may not provide the user with a desired degree of flexibility and freedom due to the presence of hoses and such that couple the fastening tool to a source of pneumatic power. Similarly, many features of typical fasteners, while adequate for their intended purpose, do not provide the user with the most efficient and effective function. Accordingly, there remains a need in the art for an improved fastening tool.
SUMMARY OF THE INVENTION
A nailer is provided having a magazine assembly with improved features. An improved latch mechanism for clearing nail jams is provided that reduces wear on the latch. A driver retention feature is provided to keep a nail driver and a nail aligned and to constrain buckling loads. A pusher assembly is provided having a simplified and efficient construction. A pusher retention feature is provided that allows the pusher assembly to move behind nails loaded in the magazine assembly. A nail retention feature is provided to allow easy loading and unloading of nails into the nailer. Finally, a method of assembling the magazine assembly is provided.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a side view of an exemplary nailer having a magazine assembly constructed according to the principles of the present invention;
FIG. 2 is a perspective view of a nosepiece of the nailer having a latch mechanism used with the magazine assembly of the present invention;
FIG. 3 is a back perspective view of a latch wire and latch tab used with the latch mechanism of the present invention;
FIG. 4 is a side view of the nosepiece having a driver blade and nail retention mechanism used with the magazine assembly of the present invention;
FIG. 5A is a perspective disassembled view of a nail pusher used with the magazine assembly of the present invention;
FIG. 5B is a top view of the nail pusher of FIG. 5A ;
FIG. 6A is a front view of the nosepiece having a nail pusher pocket feature used in the magazine assembly of the present invention;
FIG. 6B is a side sectional view of the nosepiece having a nail stop used in the magazine assembly of the present invention;
FIG. 7A is a top view of a nail retention system used in the magazine assembly of the present invention in an unlocked position;
FIG. 7B is a side view of the nail retention system shown in FIG. 7A ;
FIG. 7C is a top view of the nail retention system of FIG. 7A in a locked position;
FIG. 7D is a side view of the nail retention system shown in FIG. 7C ;
FIG. 8A is an expanded side view of the magazine assembly of the present invention illustrating a method of assembling the magazine assembly; and
FIG. 8B is an enlarged perspective view of the area indicated by circle 8 B- 8 B in FIG. 8A .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
With reference to FIG. 1 , a magazine assembly 10 constructed according to the principles of the present invention is shown in operative association with an exemplary cordless nailer 12 . It should be appreciated, however, that the present invention may be employed with various other nailers. The cordless nailer 12 generally includes a housing 14 with a motor (not shown) located therein. The motor drives a nail driving mechanism for driving nails (not shown) from the magazine assembly 10 . A handle 16 extends from the housing 14 and terminates in a battery pack 18 . The battery pack 18 is configured to engage a base portion 20 of the handle 16 and provides power to the motor.
The magazine assembly 10 includes a nosepiece assembly 22 and a magazine 24 . The nosepiece assembly 22 is mounted to the housing 14 . The magazine 24 is coupled to the nosepiece assembly 22 at one end thereof and is mounted to the base 20 of the handle 16 at an opposite end thereof.
Turning to FIG. 2 , the nosepiece assembly 22 includes a latch mechanism 26 having an improved design. The nosepiece assembly 22 includes a nosepiece 28 that is mounted to a backbone structure (not shown) within the housing 12 ( FIG. 1 ) at an end 30 thereof. The nosepiece 28 includes a pair of hooks 32 that extend upwards therefrom. A nose cover 34 is pivotally mounted to the nosepiece 28 near the end 30 at a pin connection 36 extending between a pair of lugs 37 . The nose cover 34 extends along the length of the nosepiece 28 between the hooks 32 . The nose cover 34 includes a rib 38 that extends along its length. The rib 38 provides strength to the nose cover 34 and provides a line-of-sight for the operator of the nailer 12 to align the nails (not shown). The nosepiece 28 and the nose cover 34 define a channel (as will be described in greater detail below) that receives a nail therein.
The latch mechanism 26 is mounted to the nose cover 34 and includes a latch tab 40 and a latch wire 42 , as best illustrated in FIG. 3 . The latch mechanism 26 is used to lock and unlock the nose cover 34 to the nosepiece 28 . The latch tab 40 is pivotally connected to the nose cover 34 at pin 44 .
With reference to FIG. 3 , the latch wire 42 is pivotally coupled to the latch tab 40 at enlarged slots 46 . The enlarged slots 46 allow the latch wire 42 to be easily installed on the latch tab 40 and to eliminate the need for swaging the latch wire 42 into the slots 46 . The latch wire 42 has a pair of parallel “s” shaped arms 48 (viewed from the side) which may be perpendicular to a center portion 49 . It should be appreciated that various other shapes having the “s” shaped arms 48 may be employed. The center portion 49 has a hump portion 51 sized to fit over the rib 38 (as best seen in FIG. 2 ).
With reference to FIGS. 2 and 3 , when the nose cover 34 is in its locked position over the nosepiece 28 , the latch wire 42 is locked firmly within the hooks 32 of the nosepiece 28 . The center portion 49 in turn presses firmly down upon the nose cover 34 on each side of the rib 38 . This assures that the nose cover 34 is tightly engaged to the nosepiece 28 . To unlock the nose cover 34 , the latch tab 40 is urged away from the nose cover 34 . This in turn disengages the latch wire 42 from the hooks 32 , thus allowing the nose cover 34 to pivot about the pin connection 36 away from the nosepiece 28 . In the unlocked position, an operator may then clear any nail jams within the nosepiece assembly 22 .
Turning now to FIG. 4 , a driver retention feature will be described. The nosepiece 28 includes a groove 50 formed therein that cooperates with the nose cover 34 (when the nose cover 34 is in its locked position) to form a channel 52 . The channel 52 is sized to receive a nail 53 from the magazine 24 . A driver blade 54 extends from the housing 14 into the channel 52 . The driver blade 54 is driven by the motor and nail driver mechanism (not shown) and engages the head of the nail 53 to drive the nail 53 through the nosepiece 28 and out of the nailer 12 .
However, when the nose cover 34 is in its unlocked position (shown in dashed lines in FIG. 4 ), the driver blade 54 may escape the groove 50 . Accordingly, the nose cover 34 includes a cam portion 56 (best seen in FIG. 2 ) formed at an end thereof on an opposite side of the pin connection 36 . As the nose cover 34 is moved to its unlocked position, the cam portion 56 engages the driver blade 54 , thereby constraining the driver blade 54 to the groove 50 and preventing the driver blade 54 from escaping.
Turning back to FIG. 1 , the magazine 24 holds a plurality of nails (not shown) therein. The nails are fed forward into the nosepiece assembly 22 by a pusher assembly 60 . The pusher assembly 60 rides within the magazine 24 and protrudes partially therefrom to be engaged by the operator of the nailer 12 .
Turning to FIG. 5A , the pusher assembly 60 includes a runner portion 62 , a pusher portion 64 and a spring member 80 that, at most, constitute three members to provide a simplified assembly that can be put together without tools. The runner portion 62 includes a runner 66 having a channeled portion sized to fit and slide on a liner (described in detail herein below) of the magazine 24 ( FIG. 1 ). A handle 68 extends out from the runner 66 and out from the magazine 24 . A pin 70 extends out from the runner 66 and includes a bayonet portion 72 . A hook 73 extends out from the runner 66 and receives a portion of a biasing member, as will be described below. The upper portion 62 is a one piece unitary structure.
The pusher portion 64 includes a pusher 74 that engages the nails (not shown) to move them towards the nosepiece assembly 22 ( FIG. 1 ). The pusher 74 includes a hole 76 sized to receive the pin 70 and bayonet portion 72 therein for providing a bayonet connection therebetween. An arm 78 extends out from the pusher 74 on an opposite side of the hole 76 . The runner portion 62 and the pusher portion 64 are coupled together by inserting the pin 70 into the hole 76 such that the bayonet portion 72 locks the runner portion 62 to the pusher portion 64 . The pusher portion 64 is a one piece unitary structure.
The pusher 74 includes a first surface 75 and a second surface 77 . The first surface 75 is angled with respect to the second surface 77 and includes a notch 79 formed therein, as best seen in FIG. 5B . The notch 79 is configured to partially receive nails (not shown) therein (this can best be seen in FIG. 6B ). The second surface 77 is angled to allow the driver blade 54 ( FIG. 4 ) to strike the second surface 77 , thereby moving the pusher assembly 60 out of the way of the driver blade 54 during a stroke of the driver blade 54 .
With reference to FIG. 5B , the pusher assembly 60 further includes a biasing member 80 such as, for example, a spring. The biasing member 80 is mounted between the runner 66 and the arm 78 to bias the pusher 74 such that the bayonet portion 72 cannot be accidentally disengaged from the hole 76 . Moreover, the biasing member 80 biases the pusher 74 to be in alignment with the nails (not shown) loaded within the magazine 24 ( FIG. 1 ).
Turning to FIG. 6A , as noted above, the pusher assembly 60 slides within the magazine 24 ( FIG. 1 ) to drive the nails 53 into the channel 52 of the nosepiece assembly 22 . However, when all the nails 53 have been expended from the magazine 24 , the pusher 74 enters the channel 52 . If nails have been loaded into the magazine 24 while the pusher 74 of the pusher assembly 60 is located within the nosepiece 28 , the pusher 74 would force the nails back until such time as the pusher 74 is no longer within the nosepiece 28 and the pusher 74 may move out of alignment with the loaded nails. Accordingly, the channel 52 includes a pusher pocket 82 formed therein and sized to receive the pusher 74 . This allows the pusher 74 to be moved out of alignment with the loaded nails when the pusher 74 is within the nosepiece 28 .
The nosepiece 28 further includes a nail stop 83 that bridges the channel 52 . As best seen in FIG. 6B , the nail stop engages each nail 53 as they are pushed by the pusher 74 . This assures that the head of the nail 53 within the channel 52 is aligned with the driver blade 54 . Moreover, the nail stop 83 prevents any buckling that may occur as the driver blade 54 strikes the nails 53 . The nail stop 83 is formed as part of the nosepiece 28 as a single unitary structure. This integrated nail stop 83 and nosepiece 28 reduces manufacturing costs.
Turning to FIGS. 7A-D , loading and unloading of the magazine 24 will now be described. The magazine 24 includes a nail track 90 that is sized to accept a plurality of nails 53 ( FIG. 6B ) therein. The nails 53 are supported on one end thereof within the liner 42 at another end thereof with a lower magazine (further described below) which forms part of the magazine 24 . The nails 53 slide up the magazine 24 towards the nosepiece assembly 22 ( FIG. 1 ) by the pusher assembly 60 . As noted above, the pusher assembly 60 slides along a portion of the magazine 24 , specifically, along a liner 92 shown in FIG. 1 .
Nails 53 are loaded into the nail track 90 of the magazine 24 by inserting them into the nail track 90 through an opening (not shown) in the back of magazine 24 . In order to keep the nails 53 within the nail track 90 , the magazine 24 further includes a nail retaining spring 93 ( FIGS. 7A and 7C ) mounted therein. The nail retaining spring 93 acts as a one way valve to allow nails 53 to enter the nail track 90 while preventing them from exiting. Specifically, the nail retaining spring 93 includes a spring arm 94 fixed to the magazine 24 at one end thereof and a head portion 96 at a free end thereof. The head portion 96 is aligned with the nail track 90 when in an unbiased condition (e.g., when the spring arm 94 has not been fully deflected from its rest position), as shown in FIG. 7A . The head portion 96 includes an alignment tab 98 sized to engage a portion of the pusher assembly 60 , as will be described below.
The spring arm 94 and the head portion 96 cooperate to form an inclined surface 100 such that nails 53 introduced into the magazine 24 will deflect the nail retaining spring 93 out of the way. The nail retaining spring 93 then snaps back into place, thereby preventing the nails 53 from accidentally exiting the magazine 24 .
In order to load or unload the magazine 24 , the pusher assembly 60 is moved to the back of the magazine 24 . The rear arm 78 of the pusher assembly 60 then engages a cam surface 102 ( FIG. 7C ) in the magazine 24 near the back thereof (specifically located on a portion of the magazine 24 as seen in FIG. 8 ). Simultaneously, the alignment tab 98 moves into alignment with the pusher 74 , as seen in FIGS. 7C and 7D . The cam surface 102 and the arm 78 cooperate to rotate the pusher 74 out of alignment with the nail track 90 , as seen in FIG. 7C , against the force of the biasing member 80 . This rotation is transferred to the nail retaining spring 93 through the alignment tab 98 . Accordingly, the nail retaining spring 93 is moved out of alignment with the nail track 90 by the pusher 74 . Nails 53 may then freely exit (or enter) the nail track 90 without interference. In this way, the pusher assembly 60 cooperates with the nail retaining spring 93 to allow the magazine to be loaded in either a “load and draw” mode (e.g., wherein, nails are first inserted in the magazine 24 and then the pusher assembly 60 is then “rotated” out of the plane of the nail track 90 upon contact with the nails and drawn behind the loaded nails) or in a “cock and load” mode (e.g., wherein, the pusher assembly 60 is drawn to the back of the magazine and cocked out of alignment with the nail track 90 by the cam surface 102 thereby allowing nails to be loaded and unloaded without restriction).
Turning now to FIG. 8A , the assembly of the magazine assembly 10 will be described. As noted previously, the nosepiece assembly 22 is fixed to a backbone structure (not shown) within the housing 14 of the nailer 12 . The magazine 24 generally includes the liner (or guide) 92 , a lower magazine 91 , and an upper magazine 95 .
First, the lower magazine 91 is coupled to the nosepiece assembly 22 near the lower end of the nosepiece assembly 22 . In the particular example provided, screws 97 are used to couple the lower magazine 91 to the nosepiece assembly 22 , although various other methods may be employed.
Next, the liner 92 is inserted into a receiver 110 in the nosepiece assembly 22 from the back thereof. The pusher assembly 60 is coupled to the liner 92 such that the runner 66 slidingly engages the liner 92 . A constant force spring 112 (in the form of an axle-free rolled memory-type sheet steel) is then hooked onto hook 73 of the pusher assembly 60 . The constant force spring 112 engages a portion of the magazine 24 as will be described below and biases the pusher assembly 60 towards the nosepiece assembly 22 . The liner 92 is then coupled to a base portion 116 on the lower magazine 91 . As seen in FIG. 8B , the base portion 116 on the lower magazine 91 includes a slot 118 for receiving an end of the liner 92 therein. The slot 118 includes a plurality of ribs 119 that engage the liner 92 and create a snap-fit or tight engagement therebetween. Alternatively, the base portion 116 may include a hole (not shown) sized to receive the liner 92 therein, or may include any other means of locking the liner 92 to the lower magazine 91 .
Returning to FIG. 8A , the liner 92 and lower magazine 91 cooperate to form a fixed subassembly 93 . The upper magazine 95 is then inserted overtop of the base portion 116 of the lower magazine 91 and overtop of the liner 92 . Specifically, the upper magazine 95 includes a screw receiver 120 extending therefrom with a wall 121 formed near the screw receiver 120 . The screw receiver 120 is sized to fit within an opening 124 formed in the housing 14 of the nailer 12 . A screw 123 , as seen in FIG. 1 , extends through the housing 14 and engages the screw receiver 120 , thereby securing the upper magazine 95 to the nailer 12 . The wall 121 aligns with the opening 124 thereby covering the opening 124 .
The upper magazine 95 further includes a spring retainer 122 extending therefrom. The spring retainer 122 has a cup shape and is sized to receive and secure the rolled portion of the constant force spring 112 therein. As the pusher assembly 60 is drawn away from the nosepiece assembly 22 , the constant force spring 112 acts to bias the pusher assembly 60 towards the nosepiece assembly 22 .
A ribbed flange 126 extends out from the upper magazine 95 and engages a matching ribbed recess 128 formed in the base 20 of the nailer 12 as the upper magazine 95 is coupled to the lower magazine 91 and the housing 14 . The ribbed flange 126 lends structural support to the magazine assembly 10 when assembled. Moreover, the upper magazine 95 includes ramps 134 formed therein for aligning the liner 92 when the upper magazine 95 is coupled overtop the subassembly 93 . In this way, the components of the subassembly 93 are fixed automatically during alignment thereof to reduce the number of components that must be held in place manually by an individual.
The method of assembling the magazine assembly 10 allows a user to quickly and efficiently do so by creating subassemblies which aid alignment. Moreover, engagement of the parts of the magazine 24 within receivers and apertures allows for quick and easy alignment of the parts.
The description of the invention is merely exemplary in nature and, thus, 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. | A cordless nailer is provided having a magazine assembly with improved features. An improved latch mechanism for clearing nail jams is provided that reduces wear on the latch. A driver retention feature is provided to retain a drive blade from accidentally escaping the nailer. A pusher assembly is provided having a simplified and efficient construction. A pusher retention feature is provided that prevents the driver blade from impacting a nail pusher. A nail retention feature is provided to allow easy loading and unloading of nails into the nailer. Finally, a method of assembling the magazine assembly is provided. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending application U.S. Ser. No. 11/325,662, filed Jan. 4, 2006 and also claims priority from U.S. Provisional Patent Application U.S. Ser. No. 60/641,350, filed Jan. 4, 2005. The content of the aforementioned applications is hereby incorporated by reference into this specification.
FIELD OF THE INVENTION
[0002] The invention relates to toys for children, especially those used in bathtubs and pools.
BACKGROUND OF THE INVENTION
[0003] Young children are often fascinated with running water. They see it running freely in streams, spraying out of the hose and discharging from the faucet into the kitchen sink and the bath tub. Playing with running water becomes an interesting curiosity for most children. However, playing with running water out of a faucet, whether in the sink or at bath time, can be wasteful, messy, and dangerous.
[0004] Currently, older children have the option of using outdoor water toys such as garden sprinklers and squirt guns. However, these options may not be available to particularly young children that require more direct supervision. Further, certain weather conditions, such as winter weather, may render such outdoor options unavailable.
[0005] Therefore, a means for children to explore their curiosity for running water in a controlled and safe manner is needed. Further, a means for children to explore their curiosity for running water while under direct supervision of an adult and that is not particularly dependent on outdoor weather conditions is desired.
SUMMARY OF THE INVENTION
[0006] The invention, therefore, provides a water bath toy for children to safely explore their curiosity for running water while under direct supervision of an adult. The invention provides a pump that draws water from a bath tub or pool and discharges the water back into the source. The pump is battery powered or hand powered. The invention includes a plurality of output options and a selector for choosing the active output feature. These features may include a narrow spray nozzle, a wide spray nozzle, a flexible hose, and a cascade with configurable obstructions that affect the water flow.
[0007] More particularly, the invention includes a recirculating water bath toy comprising a liquid intake port and means for outletting the liquid in fluid communication with the intake port. A selector valve that is in fluid communication with the intake port and the outletting means directs the liquid to one or more of the outletting means. An actuator engages the selector valve and is operable to cause the selector valve to direct the liquid to different outletting means. A pump is in fluid communication with the intake port and the selector valve. The water bath toy may include an outer body that is shaped to fit over a sidewall of a liquid reservoir, such as a bath tub or a pool. The outer body includes means for attaching to a sidewall of the liquid reservoir, such as a plurality of suction cups. The pump may be hand operated or battery operated, in which case, the batteries are housed in a compartment that is substantially waterproof. The outletting means may include a cascade having reconfigurable obstructions, a narrow spray nozzle, a wide spray nozzle, a flexible hose, or a combination thereof. A cover that comprises a graphical representation of cartoon characters, comic book characters, television personalities, or other forms that are pleasing to children may be fixably joined to the outer body. The graphical form may be incorporated into the outletting means.
[0008] An advantage of the present invention is that it provides a means for children to explore their curiosity for running water in a controlled and safe manner. Further, the present invention provides a water bath toy that may be used by a child under direct supervision by an adult. Even further, the present invention may be used indoors and thus is not particularly dependent on the outside weather.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become apparent and be better understood by reference to the following description of one embodiment of the invention in conjunction with the accompanying drawings, wherein:
[0010] FIG. 1 is a front isometric view of the recirculating water bath toy of the present invention;
[0011] FIG. 2 is a schematic illustrating the general water flow in the water bath toy of FIG. 1 ;
[0012] FIG. 3 is a rear view of the water bath toy of FIG. 1 ;
[0013] FIG. 4 is a side view of the water bath toy of FIG. 1 ;
[0014] FIG. 5 is a front view of the water bath toy of FIG. 1 ;
[0015] FIG. 6 is a second front isometric view of the water bath toy of FIG. 1 ;
[0016] FIG. 7 is rear isometric view of the water bath toy of FIG. 1 ; and
[0017] FIG. 8 is a front view with a cartoon figure attached to an outlet means.
[0018] Corresponding reference characters indicate corresponding parts throughout the several views. The example set out herein illustrates one embodiment of the invention but should not be construed as limiting the scope of the invention in any manner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring now to the drawings, FIGS. 1 and 2 illustrate the recirculating water bath toy and an associated water flow schematic according to one embodiment of the present invention. The water bath toy 10 includes an outer body 12 , a pump system 14 , and an outlet system 16 .
[0020] The outer body 12 includes an interface portion 20 , a pump housing 22 , a pump inlet 24 ( FIG. 3 ), a battery compartment 26 , and mounting means 28 . The interface portion 20 houses the outlet system 16 including the associated controls. The pump inlet 24 is below the surface of the water and faces the wall of a bath tub or pool when the water bath toy 10 is properly installed. Thus the pump inlet 24 is not accessible to a child. The pump inlet 24 may include a screen or other means for preventing objects from being taken up into the pump inlet 24 . The battery compartment 26 is best shown in FIGS. 3 and 7 and is a water resistant compartment in the present embodiment. FIG. 4 demonstrates that the shape of the outer body 12 is configured to fit over the wall of a bath tub or pool. The mounting means 28 , shown in FIG. 1 , aid in securing the outer body 12 to the wall of the bath tub or pool. The mounting means 28 may be rubber pads, adhesive pads, suction cups, clamps, or any combination thereof.
[0021] Referring to FIG. 2 , the pump system 14 includes a battery operated pump 30 , a pump inlet line 32 , and a pump outlet line 34 , The pump 30 is powered by batteries in the battery compartment 26 via electrical wires. Alternatively, the pump 30 is a hand operated pump. The pump inlet line 32 facilitates fluid communication between the pump inlet 24 and the pump 30 . The pump outlet line 34 facilitates fluid communication between the pump 30 and the outlet system 16 . The pump system 14 further includes a power toggle switch 36 ( FIG. 1 ) that penetrates the outer body 12 . In the present embodiment the power toggle switch 36 is remotely located in relation to the interface portion 20 and the water.
[0022] Referring to FIGS. 2 , 5 , and 6 , the outlet system 16 is shown to include a selector valve 38 , a selector valve actuator knob 40 , and a variety of output features 42 . The selector valve 38 includes a valve inlet 44 in fluid communication with the pump outlet line 34 and a plurality of valve outputs 46 configured such that only one of the valve outputs 46 is open at any particular time. Each of the valve outputs 46 is in fluid communication with an output feature 42 . The selector valve actuator knob 40 is operable to select which of the valve outputs 46 is open. In the present embodiment, the output features 42 include a wide spray feature 48 having a wide spray nozzle 50 , a narrow spray feature 52 having a narrow spray nozzle 54 , and a waterfall feature 56 having a variety of configurable obstructions 58 . The output features 42 are disposed on the surface 64 a of the front arm 64 . The obstructions 58 engage support holes 60 and may be moved around to change the affect of the obstructions 58 on the water exiting the water bath toy 10 through the waterfall feature 56 . Many further output features can be imagined that are within the scope of the invention, for example a directional hose-type outlet.
[0023] In use, the outer body 12 is mounted on a sidewall of a pool or a bath tub such that the mounting means 28 engages the sidewall. The distal end of front arm 64 of the outer body 12 is partially submerged in water such that the pump inlet 24 is at least partially submerged below water line 62 while outlet system 16 is disposed above water line 62 . Such a configuration permits the child to observe the water flowing from outlet system 16 . The back arm 66 is joined to the front arm 64 by connecting arm 68 that joints the arms at their respective ends. The water level 62 or the positioning of the outer body 12 may be adjusted to achieve this. A supervising parent activates the pump 30 by actuating the power toggle switch 36 . FIG. 2 shows that the pump 30 draws water through the pump inlet line 32 and supplies pressurized water to the selector valve 38 via the pump outlet line 34 . A child or supervising parent selects the output feature 42 by turning the selector valve actuator knob 40 to a corresponding position having an appropriate label on the face of the interface portion 20 . The pressurized water travels through the selector valve 38 to the selected output feature 42 . The selected output feature 42 in FIG. 1 is the waterfall feature 56 . The user may arrange the obstructions 58 and observe the affect that different shapes and configurations have on the water flow in the waterfall feature. To ensure the safe use of the bath toy the pump is configured to delivery water at a predetermined rate. This predetermined rate is selected to cause the water to gently trickle out of the outlet feature 42 without substantial pressure. In one embodiment, the rate of water delivery is less than about 200 mL per second. In another embodiment, the rate of water delivery is less than about 100 mL per second. In yet another embodiment, the rate of water delivery is less than about 50 mL per second.
[0024] Graphics that are pleasing to children, such as cartoon characters, comic book characters, and television personalities, may be included on the surface of the outer body 12 . Further, pleasing shapes such as cartoon characters may be incorporated into the output features 42 such that the liquid appears to be emitted from the graphic. For example, the graphic may in the shape of an elephant and the water may appear to be emitted from the elephant's trunk. The graphic may be fixably joined to the outer body using any conventional technique including adhesives or making the graphic monolithic with respect to the outer body. For example, in FIG. 8 , a graphic of an elephant head is disposed over spray nozzle 54 (see FIG. 5 ) such that water appears to be coming from a hole in the end of the elephant's trunk. In FIG. 8 , the graphic is monolithic with the interface portion 20 . In the present embodiment, durable and corrosion resistant materials such as high impact plastics and elastomers are used whenever possible.
[0025] While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the present invention using the general principles disclosed herein. Further, this application is intended to cover such departures from the present disclosure as come within the known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. | The invention provides a water bath toy having a pump that draws water from a bath tub or pool and discharges the water back into the source. The pump is battery powered or hand powered. The invention includes a plurality of output options and a selector for choosing the active output feature, These features may include a narrow spray nozzle, a wide spray nozzle, a flexible hose, and a cascade with configurable obstructions that affect the water flow. The outer body of the water bath toy is configured to fit over the sidewall of a pool or bath tub. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to PCT Application No. PCT/CH2010/000014 filed Jan. 20, 2010, which application is incorporated herein by reference and made a part hereof.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a doctor blade, in particular for scraping printing ink from a surface of a printing plate, which comprises a flat and elongated base element having a working edge region formed in a longitudinal direction, where the working edge region is coated with at least a first coating based on a nickel-phosphorus alloy. The invention further relates to a process for producing a doctor blade.
[0004] 2. Description of the Related Art
[0005] Doctor blades are used in the printing industry, especially for scraping excess printing ink from the surfaces of printing cylinders or printing rollers. Particularly in the case of gravure printing and flexographic printing, the quality of the doctor blade has a critical influence on the printing result. Unevennesses or irregularities in the working edges of the doctor blade which are in contact with the printing cylinder lead, for example, to incomplete scraping of the printing ink from the ridges of the printing cylinders. This can result in uncontrolled release of printing ink on the printing carrier.
[0006] The working edges of the doctor blade are pressed against the surfaces of the printing cylinders or printing rollers during scraping-off and are moved relative to these. The working edges are therefore, particularly in the case of rotary printing presses, subjected to high mechanical stresses which result in corresponding wear. Doctor blades are therefore basically consumables which have to be replaced periodically.
[0007] Doctor blades are usually based on a base element of steel having a specially shaped working edge. To improve the life of the doctor blade its working edges can additionally be provided with coatings or surfacings of metals and/or plastics. Metallic coatings often contain nickel or chromium which are optionally present in admixture or alloyed with other atoms and/or compounds. The nature of the coatings in terms of materials has a critical influence on, in particular, the mechanical and tribological properties of the doctor blade.
[0008] WO 2003/064157 (Nihon New Chrome Co. Ltd.), which is equivalent to U.S. Patent Publication 2005/0089706, now issued as U.S. Pat. No. 7,152,526, which applications are incorporated herein by reference and made a part hereof, describes, for example, doctor blades for printing technology which have a first layer of chemical nickel containing particles dispersed therein and a second layer having a low surface energy. The second layer preferably comprises a coating of chemical nickel containing fluorine-based resin particles or a purely organic resin.
[0009] However, doctor blades which have been coated in this way are still not fully satisfactory in respect of the life and wear resistance. In addition, it has been found that when such doctor blades are used, uncontrolled streaking can occur, especially in the running-in phase, which is likewise undesirable.
[0010] There is therefore still a need for an improved doctor blade which, in particular, has both a longer life and also allows optimal scraping-off.
SUMMARY OF THE INVENTION
[0011] It is therefore an object of the invention to provide a doctor blade of the type used in the technical field mentioned at the outset which has improved wear resistance and allows precise scraping-off, in particular of printing ink, during the entire life.
[0012] The object is achieved by providing a doctor blade, in particular for scraping printing ink from a surface of a printing plate, which comprises a flat and longitudinal base element having a working edge region formed in a longitudinal direction, where the working edge region is coated with at least a first coating based on a nickel-phosphorus alloy, wherein the first coating contains at least one additive component for improving the wear behavior of the doctor blade, where the at least one additive component comprises hard material particles, wherein the hard material particles comprise both SiC and diamond, with the particle size of the SiC being greater than the particle size of the diamond. According to the invention, the first coating contains at least one additive component for improving the wear behavior of the doctor blade.
[0013] For the purposes of the present invention, an additive component for improving the wear behavior of the doctor blade is, in particular, particles dispersed in the first coating and/or chemical substances which have been mixed in.
[0014] In the case of an additive component in the form of dispersed particles, the first coating has a heterogeneous structure which, in particular, contains the dispersed particles in the nickel-phosphorus alloy as matrix. Such coatings can also be described as mixtures. The particles are advantageously essentially uniformly distributed in the first coating. The dispersed particles can be, in particular, metals, metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and/or intermetallic phases. Suitable materials for the particles are, inter alia, one or more representatives from the group consisting of Al, Cu, Pb, W, Ti, Zr, Zn Cu, Mo, steel, WSi 2 , Al 2 O 3 , Cr 2 O 3 , Fe 2 O 3 , TiO 2 , ZrO 2 , ThO 2 , SiO 2 , CeO 2 , BeO 2 , MgO, CdO, UO 2 , SiC, TiC, WC, VC, ZrC, TaC, Cr 3 C 2 , B 4 C, BN, ZrB 2 , TiN, Si 3 N 4 , ZrB 2 and/or TiB 2 . However, other, for example completely nonmetallic and/or metal-organic particles are also possible as additive component for improving the wear behavior of the doctor blade. Completely nonmetallic particles can, for example, be present in the form of diamond.
[0015] In this context, the particle size is, in particular, a maximum dimension and/or external dimension of the particles. As regards the particle size, the particles generally have a certain distribution or scatter. When particle sizes are referred to in the present context, average particle sizes are, in particular, meant.
[0016] Additive components in the form of mixed-in chemical substances are, in particular, present as homogeneous mixtures and/or alloys. The mixed-in chemical substances can be, for example, metals. Examples of metals are, inter alia, Al, Cu, Pb, W, Ti, Zr and/or Zn. However, it is in principle also conceivable to mix metal-organic and/or nonmetallic components into the first coating.
[0017] In this context, a nickel-phosphorus alloy which forms the basis of the first coating is a mixture of nickel and phosphorus in which the phosphorus content is, in particular, 1-15% by weight.
[0018] The expression “based on a nickel-phosphorus alloy” means that the nickel-phosphorus alloy forms the main constituent of the first coating. In addition to the nickel-phosphorus alloy and the additive component for improving the wear behavior of the doctor blade, other types of atoms and/or chemical compounds can preferably well be present in a smaller proportion than the nickel-phosphorus alloy in the first coating. The proportion of nickel-phosphorus alloy in the first coating is preferably at least 50% by weight, particularly preferably at least 70% by weight and very particularly preferably at least 80% by weight. The first coating ideally consists, apart from unavoidable impurities, exclusively of the nickel-phosphorus alloy and one or more additive components for improving the wear behavior of the doctor blade.
[0019] It has been found that the doctor blades of the invention have a high wear resistance and accordingly also a long life. Furthermore, the working edges of the doctor blade of the invention are optimally stabilized. This results in a sharply delineated contact zone between the doctor blade and the printing cylinder or the printing roller, which in turn allows extremely precise scraping-off of printing ink. The contact zone remains largely stable over the entire printing process.
[0020] In addition, it has been found that the doctor blades of the invention form significantly fewer streaks during the running-in phase of the printing process or otherwise cause effects which adversely affect the printing process. The doctor blade of the invention therefore makes it possible to achieve essentially constant printing quality during the entire printing process.
[0021] Furthermore, the doctor blades of the invention have extremely advantageous sliding properties on the printing cylinders or printing rollers normally used. This also reduces wear on the printing cylinders or printing rollers when the doctor blade of the invention is used for scraping-off.
[0022] In a preferred variant of the invention, the first coating is a nickel-phosphorus alloy deposited by an electroless method. Nickel-phosphorus alloys deposited by an electroless method, which are deposited without application of electric power or an external electric current, can also be referred to chemically as nickel. Such nickel-phosphorus alloys can be formed with particularly high contour accuracy relative to the working edge of the doctor blade or relative to the base element of the doctor blade and also with a very uniform layer thickness distribution. In this way, the first coating can optimally follow the contour of the working edge of the doctor blade or the base element, which contributes decisively to the quality of the doctor blade. Nickel-phosphorus alloys deposited by an electroless method also differ, in particular, in terms of the microstructure and elasticity from electrochemically deposited nickel-phosphorus alloys. Nickel-phosphorus alloys deposited by an electroless method are also compatible both with base elements composed of plastic and with base elements composed of metal, e.g. steel, and adhere particularly well to different base elements.
[0023] However, depending on the application, it can also be advantageous for the first coating to be an electrochemically deposited nickel-phosphorus alloy. In this case, the first coating is deposited electrochemically from an electrolyte bath onto the working edge and/or the base element of the doctor blade by means of an electric current. In the case of electrochemically deposited layers, the layer thickness, in particular, can be controlled very precisely, which is particularly advantageous in the case of thin layers.
[0024] The phosphorus content of the first coating is preferably 7-12% by weight. Such coatings have been found to be particularly useful in combination with the additive components for improving the wear behavior, since, in particular, a still higher wear resistance during the entire life of the doctor blade is obtained in this way. In addition, a phosphorus content of 7-12% by weight increases the corrosion resistance, the startup resistance and the inertness of the nickel-phosphorus alloy of the first coating. A phosphorus content of 7-12% by weight likewise has a positive effect on the sliding properties of the doctor blade and on the stability of the working edge, which makes particularly exact wiping-off or scraping-off of printing ink possible. Furthermore, very good adhesion to the base elements usually used for doctor blades, e.g. steel and/or plastics, is achieved at a phosphorus content of 7-12% by weight.
[0025] However, it is in principle also possible to provide a phosphorus content lower than 7% by weight or a phosphorus content greater than 12% by weight. However, the abovementioned positive effects can decrease as a result. On the other hand, such contents of phosphorus can also bring advantages in the case of specific additive components and/or embodiments of the coatings.
[0026] The first coating advantageously has a hardness of 750-1400 HV. This increases, in particular, the wear strength of the doctor blade. Hardnesses below 750 HV are also possible, but the wear resistance of the doctor blade decreases. At hardnesses greater than 1400 HV, the printing cylinder or the printing roller can be damaged under some circumstances, as a result of which the printing quality at best decreases.
[0027] The layer thickness of the first coating is advantageously 1-30 μm. The thickness of the first coating is more preferably 5-20 μm, particularly preferably 5-10 μm. Such thicknesses of the first coating offer optimal protection of the working edge of the doctor blade. In addition, first coatings having such dimensions have a high intrinsic stability, which effectively reduces the partial or complete delamination of the first coating, for example during scraping-off of printing ink from a printing cylinder.
[0028] Although thicknesses of less than 1 μm are possible, the wear resistance of the working edge or of the doctor blade decreases rapidly in this case. Thicknesses greater than 30 μm are also possible. However, these are generally less economical and can sometimes also have an adverse effect on the quality of the working edge. However, thicknesses of less than 1 μm or greater than 30 μm can be advantageous for specific fields of use of the doctor blade.
[0029] In a further advantageous variant, a second coating based on nickel is arranged on the first coating. A second coating based on nickel can serve, in particular, as protective layer for the first coating, as a result of which the wear resistance and stability of the working edge of the doctor blade can be increased further. In addition, a second coating can serve as stable matrix for further additives and have a positive effect on scraping-off by means of the doctor blade of the invention.
[0030] The expression “based on nickel” means that nickel forms the main component of the second coating. Other types of atoms and/or chemical compounds can perfectly well be present in a proportion smaller than that of nickel in addition to nickel in the second coating. The proportion of nickel in the second coating is preferably at least 50% by weight, particularly preferably at least 75% by weight and very particularly preferably at least 95% by weight. In a particularly useful embodiment, the second coating consists, except for unavoidable impurities, exclusively of nickel.
[0031] However, a second coating having a different composition, e.g. with another metal as main constituent, can in principle also be present, or the second coating can be dispensed with entirely.
[0032] In a preferred variant, the second coating is an electrochemically deposited coating based on nickel. Such coatings form a relatively soft protective layer for the first coating, as a result of which friction and wear in the contact zone region of the doctor blade can be reduced in many applications. The reduction in friction and the associated low resistance on scraping-off leads to a particularly high wear resistance and stability of the working edge of the doctor blade in many applications.
[0033] However, for other applications, it can also be advantageous to provide a coating deposited by an electroless method as second coating.
[0034] Furthermore, the second coating is preferably based on a further nickel-phosphorus alloy. As explained in connection with the first coating, the expression “based on a further nickel-phosphorus alloy” means that the further nickel-phosphorus alloy forms the main constituent of the second coating. Here, other types of atoms and/or chemical compounds can perfectly well be present in a proportion lower than that of the further nickel-phosphorus alloy in addition to the further nickel-phosphorus alloy in the second coating. The proportion of the further nickel-phosphorus alloy in the second coating is preferably at least 50% by weight, particularly preferably at least 70% by weight and very particularly preferably at least 80% by weight. Ideally, the second coating consists, except for unavoidable impurities, exclusively of the nickel-phosphorus alloy and at most one or more additive components to improve the wear behavior of the doctor blade.
[0035] In an advantageous variant, the second coating comprises an electrochemically deposited nickel-phosphorus alloy. This is particularly advantageous in combination with a first coating based on a nickel-phosphorus alloy deposited by an electroless method. In this case, the working edges are optimally stabilized by the combination of the first coating composed of a nickel-phosphorus alloy deposited by an electroless method and containing at least one additive component for improving the wear behavior of the doctor blade and the second coating based on the electrochemically deposited nickel-phosphorus alloy. This results in a particularly sharply delineated contact zone between the doctor blade and the printing cylinder or the printing roller, which in turn makes extremely precise scraping-off of printing ink possible. The contact zone remains largely stable over the entire printing process.
[0036] The further nickel-phosphorus alloy of the second coating has a phosphorus content of 12-15% in an advantageous variant. This is particularly the case when the second coating consists, except for unavoidable impurities, essentially exclusively of the further nickel-phosphorus alloy and has been electrochemically deposited.
[0037] Particularly when the second coating based on a further nickel-phosphorus alloy is present and in addition contains at least one further additive component for improving the wear behavior of the doctor blade, the phosphorus content of the second coating is advantageously lower than the phosphorus coating of the first coating. In other words, the phosphorus content of the further nickel-phosphorus alloy of the second coating is advantageously lower than the phosphorus content of the nickel-phosphorus alloy of the first coating. The combination of coatings having different phosphorus contents gives, in particular, greater wear protection for the working edge and at the same time effects further stabilization of the working edge. A phosphorus content of the further nickel-phosphorus alloy of the second coating of 6-9% by weight has been found to be particularly useful here.
[0038] The phosphorus content of the further nickel-phosphorus alloy of the second coating can in principle also be less than 6% or more than 9%. It is likewise possible in principle to provide a comparable phosphorus content in the first coating and in the second coating or establish a higher phosphorus content in the second coating than in the first coating. Depending on the intended use of the doctor blade, this can even be advantageous.
[0039] In particular, the layer thickness of the second coating is smaller than the layer thickness of the first coating and is advantageously 0.5-3 μm. Such layer thicknesses guarantee, in particular, a high intrinsic stability of the second coating and at the same time a good protective effect for the first coating, which is overall favorable for the stability of the working edge.
[0040] However, it is also possible, in the context of the invention, to realize a second coating having a layer thickness of less than 0.5 μm or more than 3 μm. It is also possible in principle to select a layer thickness of the second coating which is equal to or greater than the layer thickness of the first coating.
[0041] Whether a second coating is provided and what composition this has depends essentially on the intended use of the doctor blade. Here, for example, the material and the nature of the surface of the printing cylinder or the printing roller plays a critical role. A second coating comprising a nickel-phosphorus alloy is generally somewhat harder and more corrosion resistant compared to a coating based on nickel which is essentially free of phosphorus.
[0042] In the case of doctor blades having two or more coatings, the following different embodiments have, in particular, been found to be advantageous:
[0043] In a first preferred embodiment of the invention, the doctor blade of the invention comprises a first coating based on a nickel-phosphorus alloy deposited by an electroless method containing hard material particles dispersed therein and in particular a second coating based on electrochemically deposited nickel or a second coating based on an electrochemically deposited nickel-phosphorus alloy adjoining the first coating.
[0044] In a further advantageous embodiment, the doctor blade has a first coating based on a nickel-phosphorus alloy deposited by an electroless method containing a first type of hard material particles dispersed therein and a second coating based on a nickel-phosphorus alloy deposited by an electroless method containing a second type of hard material particles dispersed therein adjoining the first coating. The two types of hard material particles differ, in particular, in terms of their materials compositions and/or their particle sizes.
[0045] In addition, embodiments in which the doctor blade comprises a first coating based on a nickel-phosphorus alloy deposited by an electroless method containing hard material particles dispersed therein and a second coating based on a nickel-phosphorus alloy deposited by an electroless method containing lubricating particles, in particular particles of hexagonal BN, and adjoining the first coating have been found to be particularly useful. Here, two or more types of different hard material particles can also be present in the first coating.
[0046] The wear resistances of the doctor blade in these embodiments can optionally be improved further by mixing alloying components, e.g. metals such as W, into the first and/or second coating.
[0047] If the additive component comprises lubricants, in particular lubricating particles, the lubricants are preferably arranged in the outermost coating. In this way, a constant wear improvement is, in particular, achieved right from the beginning for the doctor blades of the invention.
[0048] In another preferred embodiment, the second coating comprises a primer layer which adjoins the first coating and is composed of pure nickel and a covering layer which is arranged on top of this and is composed of nickel and/or a nickel-phosphorus alloy. The primer layer of pure nickel preferably consists, except for unavoidable impurities, exclusively of nickel. The thickness of the primer layer is preferably 0.2-0.8 μm, in particular 0.4-0.6 μm. In particular, if the covering layer also consists of pure nickel, the covering layer advantageously additionally contains saccharin and/or a saccharin salt.
[0049] A second layer made up in this way has, firstly, good adhesion to the first coating and possibly also to the base element. In addition, the second coating has, in the case of a covering layer containing saccharin and/or a saccharin salt, a very even surface with a low surface roughness, which aids formation of a sharply delineated contact zone between doctor blade and printing cylinders or printing rollers.
[0050] However, it is in principle also possible to dispense with the formation of a primer layer and a covering layer for the second coating and provide only a single and essentially homogeneous layer.
[0051] Further details regarding the preferred additive components are given below.
[0052] The at least one additive component advantageously comprises hard material particles. In a preferred variant, the hard material particles comprise metal particles. Suitable metal particles are, for example, metal particles composed of W, Ti, Zr, Mo and/or steel. The metal particles can be used either alone, in combination with other metal particles and/or in combination with further additive components.
[0053] Metal particles composed of metallic molybdenum have been found to be particularly suitable. Doctor blades having a first coating and/or a second coating based on a nickel-phosphorus alloy containing metal particles of molybdenum dispersed therein have a very high wear resistance and accordingly also a long life. The working edges of such doctor blades have a sharply delineated contact zone between the doctor blade and the printing cylinder or the printing roller, which makes more precise scraping-off of printing ink possible. In a further preferred variant, the metal particles have a particle size of 1-2 μm and a proportion by volume in the first coating of 5-30%, particularly preferably 15-20%. In a very particularly preferred embodiment, the first coating consists, except for unavoidable impurities, exclusively of the nickel-phosphorus alloy and the metal particles, in particular molybdenum particles, dispersed therein.
[0054] In another advantageous embodiment, the hard material particles can comprise, instead of or in addition to the metal particles, metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and/or intermetallic phases. These can be, for example, one, two or more representatives from the group consisting of WSi 2 , Al 2 O 3 , Cr 2 O 3 , Fe 2 O 3 , TiO 2 , ZrO 2 , ThO 2 , SiO 2 , CeO 2 , BeO 2 , MgO, CdO, UO 2 , SiC, TiC, WC, VC, ZrC, TaC, Cr 3 C 2 , B 4 C, cubic BN, ZrB 2 , TiN, Si 3 N 4 , ZrB 2 , TiB 2 . Although B 4 C (boron carbide) is in the strictest sense not a metal carbide, B 4 C will in the present context be included among metal carbides because of the similar materials properties.
[0055] Doctor blades having a first coating and/or a second coating based on a nickel-phosphorus alloy containing metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and/or intermetallic phases dispersed therein have a high wear resistance and accordingly also a long life. Such hard material particles can be embedded extremely stably in the first coating and form a strong, stable bond with the nickel-phosphorus alloy of the first coating. In this way, the strength of the first coating can be improved overall and at the same time the working edges of such doctor blades display a sharply delineated contact zone between the doctor blade and the printing cylinder or the printing roller, which in turn makes more precise scraping-off of printing ink possible.
[0056] The following metal carbides and/or metal nitrides in particular have been found to be particularly useful: B 4 C, cubic BN, TiC, WC and/or SiC. Among the metal oxides, Al 2 O 3 is particularly advantageous.
[0057] However, the hard material particles do not necessarily have to be present in the form of metal particles, metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and/or intermetallic phases. In principle, particles of other materials are also possible as hard material particles.
[0058] In a further advantageous variant, the hard material particles comprise diamond. Preference is given to using diamond having a monocrystalline and/or polycrystalline structure. Hard material particles composed of diamond have been found to be particularly advantageous in the doctor blades of the invention and bring about, in particular, a further improvement in the wear resistance and stabilization of the working edges of the doctor blade. This could be attributable, inter alia, to the high hardness and the chemical and mechanical stability of diamond. However, diamond is not to be confused with other forms of carbon such as graphite, glassy carbon, graphene or carbon black. These forms of carbon bring about the advantages according to the invention to only a limited extent or not at all.
[0059] As has been found, it is in principle also possible to use, instead of or in addition to hard material particles composed of diamond having a monocrystalline and/or polycrystalline structure, particles of amorphous diamond-like carbon (“DLC”). However, the amorphous diamond-like carbon advantageously has a high proportion of sp 3-hybridization so that a sufficient hardness is ensured. Depending on the intended use of the doctor blade, amorphous diamond-like carbon can even have advantages. In general, amorphous diamond-like carbon is also cheaper than diamond.
[0060] Hard material particles having a particle size in the range 5 nm-4 μm, in particular 0.9-2.5 μm, particularly preferably 1.4-2.1 μm, are particularly useful. The tribological properties of the doctor blades of the invention can be improved further by use of such particle sizes.
[0061] The particle size of the hard material particles is advantageously matched to the respective material of the hard material particles.
[0062] Thus, hard material particles in the form of metal particles particularly preferably have a particle size of 0.5-2.5 μm, in particular 1-2 μm. In the case of metal oxides, metal carbides, metal nitrides, metal carbonitrides, metal borides, ceramics and/or intermetallic phases, particle sizes of 1.0-2.5 μm, in particular 1.5-2.0 μm, have been found to be particularly advantageous.
[0063] Diamond particles as hard material particles advantageously have a particle size of 5 nm-1.1 μm. Furthermore, the particle size of diamond particles is preferably less than 300 nm. In particular, the particle size of diamond particles is in the range 100-200 nm. However, such particle sizes are not absolutely necessary. In the case of specific embodiments and/or uses of the doctor blades, diamond particles having particle sizes of 5-50 nm have also been found to be advantageous.
[0064] When hard material particles having particle sizes below 5 nm are used, the wear resistance, in particular, of the working edge of the doctor blade usually decreases, as a result of which the life of the doctor blade is shortened. In the case of particle sizes greater than 4 μm, it is possible for the doctor blade to have an increased surface roughness, which is generally undesirable. However, greater particle sizes can, in particular, also be suitable for specific uses and/or doctor blade structures.
[0065] The proportion by volume of the additive component for improving the wear properties is, particularly in the case of particulate additive components, preferably 5-30%, particularly preferably 15-20%. A significant improvement in respect of the wear properties and the stability of the working edge is achieved at such proportions.
[0066] Although lower proportions by volume are likewise possible, they generally display a less satisfactory improvement in the wear resistance. Excessively high proportions by volume of the additive component can likewise have an adverse effect on the properties of the doctor blade. However, proportions by volume above 30% may possibly also be suitable for specific applications.
[0067] In a further advantageous variant, the hard material particles comprise different particles of at least two different materials. As has been found, synergistic effects can be brought about thereby so as to improve the wear resistance and quality of the doctor blade to a far greater extent than expected. Furthermore, it can be advantageous for the hard material particles to comprise different particles having at least two different particle sizes.
[0068] The hard material particles particularly preferably comprise both SiC and diamond, with the particle size of the SiC more preferably being greater than the particle size of the diamond. In particular, the hard material particles comprise SiC having a particle size of 1.4-2.1 μm and diamond having a particle size of 5 nm-1.1 μm, preferably 200-300 nm.
[0069] However, it is also possible to select the particle sizes of SiC and diamond differently, so that, for example, the particle size of the diamond is equal to or greater than the particle size of the SiC. In addition, other combinations of hard material particles are also possible, with more than two, e.g. three, four or even more, different hard material particles also being able to be combined with one another.
[0070] In another preferred variant of the invention, the hard material particles comprise, for example, both SiC and cubic BN, with the particle size of the BN preferably corresponding approximately to the particle size of the SiC. The particle sizes of the SiC and of the cubic BN are particularly preferably about 1.4-2.1 μm.
[0071] Furthermore, it has been found to be advantageous for the additive component for improving the wear resistance to comprise lubricants, in particular lubricating particles. In this way, a lubricating effect can be additionally achieved during scraping-off, which reduces wear. Possible lubricants or lubricating particles are in principle substances which bring about a reduction in the sliding friction between doctor blade and printing cylinder and are, in particular, sufficiently stable for no damage to or fouling of the printing cylinder to occur.
[0072] Possibilities are, for example, polymeric thermoplastics, e.g. perfluoroalkoxyalkane and/or polytetrafluoroethylene, and also graphite, molybdenum disulfide and/or soft metals such as aluminum, copper and/or lead.
[0073] Hexagonal BN has been found to be particularly advantageous as lubricant, especially when used in particulate form. As has been found, the wear resistance of the doctor blade has been able to be improved in many applications using different printing cylinders by means of lubricants, in particular lubricating particles of hexagonal BN. This is, in particular, largely independent of the process parameters during scraping-off. In other words, hexagonal BN has been found to be an extremely versatile and effective lubricant.
[0074] A likewise well-suited lubricant is, for example, polytetrafluoroethylene (PTFE). Polytetrafluoroethylene is also preferably used in the form of lubricating particles.
[0075] Lubricating particles, in particular lubricating particles of hexagonal BN, advantageously have a particle size of 50 nm-1 μm, preferably 80-300 nm, more preferably 90-110 nm. This gives an optimal effect for many applications. However, other particle sizes can in principle also be suitable for specific applications.
[0076] In a particularly preferred embodiment, both lubricants, in particular lubricating particles, and hard material particles are present as additives for improving the wear resistance in the first coating and/or any second coating. Lubricating particles composed of hexagonal BN are ideally used in this case together with hard material particles composed of SiC.
[0077] In a further preferred embodiment of the invention, the additive component comprises an additional alloying component in the first coating and/or any second coating. In this way, the physical and chemical properties of the first and/or second coating can be matched further to the conditions prevailing during scraping-off. The properties of the coatings can be modified by means of the additional alloying component which, in particular, mixes completely with the first and/or second coating, without thereby affecting the homogeneity. As alloying component, it is possible to use, for example, metals. Examples of metals are, inter alia, Al, Cu, Pb, W, Ti, Zr and/or Zn. However, it is in principle also conceivable to mix metal-organic and/or nonmetallic components into the first and/or second coating.
[0078] The additional alloying component particularly preferably comprises a transition metal, in particular tungsten (W). The mixing in of W in particular can improve the wear resistance of the doctor blade. At the same time, when such doctor blades are used, a sharply delineated contact zone is obtained between working edge and printing cylinder, which makes particularly precise scraping-off of printing ink possible. However, for specific applications, it is also possible, for example, to use other alloying components.
[0079] The proportion of the alloying components in the first coating is advantageously 0.0001-12% by weight. The proportion of the alloying component is more preferably 0.5-5% by weight. In a further preferred embodiment, the proportion of the alloying component is 1-3% by weight.
[0080] It is also advantageous for both an additional alloying component and hard material particles to be present as additive component. The advantages according to the invention can be further improved in this way.
[0081] The additive component preferably comprises metallic W as alloying component and also SiC and diamond as hard material components. The particle size of the SiC is, in particular, greater than the particle size of the diamond. Particular preference is given to SiC being present in a particle size of 1.4-2.1 μm and diamond being present in a particle size of 10 nm-1.1 μm, preferably 200-300 nm.
[0082] However, other combinations of alloying components and hard material particles are in principle also possible.
[0083] In a preferred embodiment, the base element of the doctor blade comprises metal, in particular steel. Steel has from a mechanical point of view been found to be a particularly robust and suitable material for the doctor blades of the invention.
[0084] Preference is here given to at least one surface region of the base element present in the longitudinal direction to be completely covered all around with the first coating, the second coating and/or a further coating. In this way, at least the working edge, the upper side, the under side and the rear end face opposite the working edge of the base element are covered with at least one coating. The side faces of the base element perpendicular to the longitudinal direction can be uncoated. However, it is also within the scope of the invention for the second coating to cover the base element completely and on all sides, i.e. the side faces of the base element perpendicular to the longitudinal direction are also covered with one of the coatings. In this case, at least one coating surrounds the base element all around.
[0085] As a result of at least one of the surface regions present in the longitudinal direction of the base element being covered completely and all around with at least one coating, the essential regions of the base element which do not belong to the working edge are also provided with the second coating. This is particularly advantageous in order to protect the base element from water-based or slightly acidic printing inks and/or other liquids that come into contact with the doctor blade. Particularly in the case of base elements made of steel, optimal protection against rusting is in this way provided for the doctor blade. The constancy of the print quality during the printing process is thus improved further since the printing cylinder or the printing roller which is in contact with the doctor blade during the printing process is, for example, not contaminated by rust particles. Furthermore, the base element is protected as well as possible against rust formation by a second coating applied in the surface region, even during storage and/or transport.
[0086] However, it is also possible to use, for example, other metals or metal alloys instead of steel as base element.
[0087] In a further preferred embodiment, the base element comprises a plastics material. For specific applications, base elements made of plastics have sometimes been found to be more advantageous than base elements made of steel because of their different mechanical and chemical properties. Thus, some of the possible plastics have satisfactory chemical stability or inertness toward typical water-based and slightly acidic printing inks, as a result of which the base element does not have to be specially protected, as in the case of a base element made of steel.
[0088] Possible plastics materials are, for example, polymer materials. These can be, inter alia, thermoplastic, thermoset and/or elastomeric polymer materials. Suitable plastics are, for example, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, polyethylene terephthalate, polyamide, polyacetal, polycarbonate, polyarylate, polyether ether ketone, polyimide, polyester, polytetrafluoroethylene and/or polyurethane. Composite structures having fibers for reinforcing the polymer matrix are also possible.
[0089] However, it is in principle also possible to use base elements which, for example, comprise both metal, in particular steel, and plastic. Base elements comprising other materials, e.g. ceramics and/or composites, may also be suitable for specific applications.
[0090] In an advantageous process for producing a doctor blade, in particular a doctor blade according to the invention, a first coating based on a nickel-phosphorus alloy is deposited on a working edge region formed in a longitudinal direction of a flat and elongated base element in a first step, where at least one additive component for improving the wear behavior of the doctor blade is mixed into the first coating.
[0091] The deposition of the first coating is, in particular, carried out by an electroless method and advantageously from an aqueous solution. Such deposition of the nickel-phosphorus alloy with mixing in of the additive component for improving the wear behavior makes it possible to produce a high-quality first coating which, in particular, has a high contour accuracy relative to the working edge of the doctor blade or relative to the base element of the doctor blade and also a very uniform layer thickness distribution. In other words, the electroless deposition forms an extremely uniform nickel-phosphorus alloy which contains a uniformly distributed additive component and optimally follows the contour of the working edge of the doctor blade or the base element, which contributes decisively to the quality of the doctor blade. Furthermore, a first coating which, in particular, is as compatible as possible with a second coating based on nickel to be applied to the first coating can be formed by the electroless deposition. This ensures satisfactory adhesion of the second coating to the first coating. To carry out the electroless coating, the working edge or optionally the entire base element of the doctor blade is dipped into a suitable electrolyte bath containing mixed in additive component and is coated in a manner known per se. The additive component mixed into the electrolyte bath is incorporated into the nickel-phosphorus alloy during the coating or deposition process and is essentially randomly distributed in the nickel-phosphorus alloy formed.
[0092] Owing to the electroless deposition of the nickel-phosphorus alloy, it is in principle also possible to use plastics as base elements for the doctor blade and provide them in a simple way with the first coating composed of the nickel-phosphorus alloy and the additive component.
[0093] However, it is in principle also possible to choose another deposition process. For example, the first coating can also be deposited electrochemically or by means of a gas-phase process, insofar as this appears suitable for the purpose.
[0094] The first coating is advantageously deposited in aqueous solution and preferably with air being blown in. As a result of the air being blown in, improved mixing, in particular, of the substances to be deposited is achieved, which has a positive effect on the quality of the first coating.
[0095] However, it is also possible to undertake other measures for improving mixing instead of or in addition to blowing in of air. This can be achieved, for example, by means of a mechanical stirrer.
[0096] In an advantageous variant, an alloying component which is preferably a metal and/or a metal salt is mixed in as additive component. Particular preference is given to using a tungsten salt as metal salt. The deposition of the first coating is advantageously carried out from an aqueous solution by an electroless method, preferably using sodium tungstate dihydrate having the empirical formula Na 2 WO 4 .2H 2 O as tungsten salt. If necessary, complexing agents known per se can be additionally introduced together with the tungsten salt.
[0097] The tungsten salt is advantageously present in a proportion of about 5-20 g/liter, preferably 10-12 g/liter, in the aqueous solution. This corresponds to a proportion of about 2.7-10.9 g/liter, in particular 5.5-6.5 g/liter, of the element tungsten in the aqueous solution.
[0098] As a result of the mixing in of the tungsten salt, the tungsten is, in particular, incorporated as alloying component into the nickel-phosphorus alloy. This makes it possible to obtain an extremely uniform nickel-phosphorus alloy which has improved wear resistance. In particular, the hardness and corrosion resistance of the nickel-phosphorus alloy can be improved by the incorporation of tungsten.
[0099] Other additive components such as hard material particles and/or lubricating particles can also be mixed in in addition to or instead of the alloying component.
[0100] The aqueous solution preferably has a pH of 8-9 during deposition. Such high pH values have surprisingly been found to have, in particular, a positive influence on the quality of the deposited coating during the deposition of alloying components. The wear resistance of the doctor blade can be significantly improved thereby and the contact region between the working edge of the doctor blade and the printing cylinder remains very constant during the entire life of the doctor blade. This in turn promotes precise scraping-off of printing ink.
[0101] If a second coating is provided, a second coating based on nickel is preferably deposited on at least a subregion of the first coating in a second step. The first coating is preferably completely covered by the second coating.
[0102] In a first advantageous variant, the second coating is deposited by an electrochemical method in the second step. This has, in particular, been found to be advantageous for second coatings without particulate additive components. Second coatings which consist, except for unavoidable impurities, exclusively of nickel or a nickel-phosphorus alloy are thus advantageously deposited electrochemically.
[0103] The electrochemical process which may be carried out in the second step can be carried out in a manner known per se. The regions of the doctor blade which are to be coated, in particular the working edge provided with the first coating, are in this case dipped, for example, into a suitable electrochemical electrolyte bath. The regions to be coated function as cathode, while, for example, a soluble consumable electrode comprising nickel serves as anode. However, it is in principle also possible, depending on the material to be deposited, to use insoluble anodes. Application of a suitable electric potential between cathode and anode results in flow of electric current through the electrochemical electrolyte bath, as a result of which elemental nickel or, for example, a nickel-phosphorus alloy deposits on the regions of the doctor blade which are to be coated and forms the second coating. The second coatings produced by the electrochemical process are pure and of high quality. In principle, an additive component for improving the wear resistance and/or other additives can be added to the electrolyte bath in order to improve the quality of the second coating further; these can optionally also be incorporated into the second coating.
[0104] The electrochemical deposition of a nickel-phosphorus alloy also has process engineering advantages over electroless deposition. Thus, the phosphorus content, for example, can be controlled very well and the deposition can be carried out at high deposition rates. Likewise, the electrochemical deposition of a nickel-phosphorus alloy has the advantage over the electrochemical deposition of nickel that insoluble anodes can also be used.
[0105] In a second advantageous variant, the deposition of the second coating is carried out by an electroless method, in particular from an aqueous solution. This procedure is advantageous particularly when particulate additive components, e.g. hard material particles and/or lubricating particles, are integrated into the second coating. In particular, a uniform distribution of the particulate additive components to be integrated into the second coating is achieved by electroless deposition.
[0106] A heat treatment for hardening the first and optionally also the second coating is advantageously carried out in a third step which is carried out after the first and/or second step. The heat treatment induces solid state reactions in the nickel-phosphorus alloys, which increase the hardness of the nickel-phosphorus alloys. Since the heat treatment is carried out only after deposition or application of a susceptible second coating, oxide formation, in particular, on the surface of the first coating is prevented. This firstly results in good adhesion between the first coating and any second coating present and secondly improves the overall uniformity of the doctor blade in the region of the working edge.
[0107] In principle, a heat treatment can also be omitted. However, this is at best at the cost of the wear resistance and life of the doctor blade produced according to the invention.
[0108] In particular, the coated base element is heated to a temperature of 100-500° C., particularly preferably a temperature in the range 170-300° C., during the heat treatment. These temperatures are, in particular, maintained over a hold time of 0.5-15 hours, preferably 0.5-8 hours. Such temperatures and hold times have been found to be optimal in order to achieve satisfactory hardnesses of the nickel-phosphorus alloys.
[0109] Temperatures of less than 100° C. are likewise possible. However, in this case very long and usually uneconomical hold times are necessary. Temperatures above 500° C. are in principle also possible, depending on the material of the base element, but the hardening process for the nickel-phosphorus alloy is more difficult to control in this case.
[0110] In another advantageous variant, a primer layer of nickel is firstly deposited at a pH of less than 1.5, in particular at a pH of less than 1, by means of an electrochemical process during the electrochemical process in the second step. In a further step, for example, a covering layer of nickel can subsequently be deposited using saccharin at a pH of 2-5, in particular at a pH of 3.4-3.9.
[0111] Owing to the acidic conditions, the surface of the working edge to be coated or of the first coating is chemically activated so that the primer layer forms an extremely stable bond to the working edge. The primer layer represents an optimal substrate for the covering layer to be deposited on top. Maintenance of a pH of 2-5 and the use of saccharin give an optimal covering layer having a smooth and even surface.
[0112] In principle, the primer layer and the covering layer can also be deposited under other conditions.
[0113] In particular, it is also possible to deposit a primer layer composed of nickel at a pH of less than 1.5, in particular at a pH of less than 1, by means of an electrochemical process and subsequently apply, for example, a covering layer in the form of a nickel-phosphorus alloy. The nickel-phosphorus alloy can in this case also contain, for example, an additive component for improving the wear behavior of the doctor blade.
[0114] Further advantageous embodiments and combinations of features of the invention can be derived from the following detailed description and the totality of the claims.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0115] The drawings used for explaining the illustrative embodiment show:
[0116] FIG. 1 is a cross section through a first lamellar doctor blade according to the invention, where a working edge of the lamellar doctor blade is coated with a nickel-phosphorus alloy and hard material particles dispersed therein;
[0117] FIG. 2 is a cross section through a second lamellar doctor blade according to the invention, where a working edge of the lamellar doctor blade is coated with a nickel-phosphorus tungsten alloy;
[0118] FIG. 3 is a cross section through a third lamellar doctor blade according to the invention which is coated in the region of the working edge with a first coating containing hard material particles dispersed therein and a second coating which is composed of pure nickel and is arranged on the first coating and completely surrounds the doctor blade;
[0119] FIG. 4 is a variant of the doctor blade of FIG. 3 , where the second coating is present only in the region of the first coating;
[0120] FIG. 5 is a cross section through a fifth lamellar doctor blade according to the invention which is coated in the region of the working edge with a first coating containing hard material particles dispersed therein and a two-layer second coating of nickel arranged thereon;
[0121] FIG. 6 is a cross section through a sixth lamellar doctor blade according to the invention which is coated in the region of a working edge with a first coating containing hard material particles dispersed therein and a second coating which is arranged on top of the first coating and contains lubricating particles of hexagonal boron nitride dispersed in the second coating;
[0122] FIG. 7 is a cross section through a seventh lamellar doctor blade according to the invention which is coated in the region of a working edge with a first coating containing two different types of hard material particles dispersed therein and a second coating which is arranged on top of the first coating and contains lubricating particles dispersed in the second coating; and
[0123] FIG. 8 is a schematic depiction of a process according to the invention for producing a doctor blade.
[0124] In the figures, identical parts are basically provided with the same reference numerals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0125] FIG. 1 depicts a lamellar doctor blade 100 according to the invention in cross section. The lamellar doctor blade 100 comprises a base element 110 made of steel which on the left-hand side in FIG. 1 has a rear region 120 having an essentially rectangular cross section. The rear region 120 is provided as a fastening region in order to hold the lamellar doctor blade in, for example, an appropriate holding device of a printing machine. The doctor blade thickness measured from the upper side 121 to the under side 122 of the rear region is about 0.2 mm. The length of the base element 110 or the lamellar doctor blade 100 measured perpendicular to the plane of the plate is, for example, 1000 mm.
[0126] On the right-hand side in FIG. 1 , the base element 110 is tapered stepwise from the upper side 121 of the rear region 120 to form a working edge 130 . An upper side 131 of the working edge 130 lies on a plane below the plane of the upper side 121 of the rear region 120 but is essentially parallel to the upper side 121 of the rear region 120 . Between the rear region 120 and the working edge 130 , there is a concave transition region 125 . The under side 122 of the rear region 120 and the under side 132 of the working edge 130 are in the same plane which is parallel to the upper side 121 of the rear region 120 and parallel to the upper side 131 of the working edge 130 . The width of the base element 110 , measured from the end of the rear region to the front face 140 of the working edge 130 is, for example, 40 mm. The thickness of the working region 130 , measured from the upper side 131 to the under side 132 of the working region, is, for example, 0.060-0.150 mm, which corresponds approximately to half the thickness of the doctor blade in the rear region 120 . The width of the working region 130 , measured from the upper side 131 of the working region 130 from the front face 140 to the transition region 125 , is, for example, 0.8-5 mm.
[0127] A free front face 140 of the free end of the working edge 130 runs obliquely downward from the upper side 131 of the working edge 130 to the under side 132 of the working edge 130 . The front face 140 makes an angle of about 45° or 135° to the upper side 131 of the working edge 130 or to the under side 132 of the working edge 130 , respectively. An upper transition region between the upper side 131 and the front face 140 of the working edge 130 is rounded. Likewise, a lower transition region between the front face 140 and the under side 132 of the working edge 130 is rounded.
[0128] The working edge 130 of the lamellar doctor blade 100 is also surrounded by a first coating 150 . The first coating 150 completely covers the upper side 131 of the working edge 130 , the transition region 125 and an adjoining subregion of the upper side 121 of the rear region 120 of the base element 110 . Likewise, the first coating 150 covers the front face 140 , the under side 132 of the working edge 130 and a subregion of the under side 122 of the rear region 120 of the base element 110 which adjoins the under side of the working edge 130 .
[0129] The first coating 150 consists, for example, of a nickel-phosphorus alloy having a phosphorus content of 9% by weight. Hard material particles 160 , e.g. particles of silicon carbide (SiC), are dispersed therein. The proportion by volume of the hard material particles 160 is, for example, 16% and the average particle size of the hard material particles 160 is about 1.6 μm. The layer thickness of the first coating 150 in the region of the working edge 130 is, for example, 15 μm, while the hardness is, for example, 1200 HV. The layer thickness of the first coating 150 decreases continuously in the region of the upper side 121 and the under side 122 of the rear region 120 , so that the first coating 150 runs to its end in the form of a wedge in a direction away from the working edge 130 .
[0130] FIG. 2 shows a second lamellar doctor blade 200 according to the invention in cross section. The second lamellar doctor blade 200 has a base element 210 having a rear region 220 and a working edge region 230 and has essentially the same construction as the first lamellar doctor blade 100 from FIG. 1 . The upper side 231 of the working edge 230 , the transition region 225 and an adjoining subregion of the upper side 221 of the rear region 220 of the base element 210 and also the front face 240 , the under side 232 of the working edge 230 and a subregion of the under side 222 of the rear region 220 of the base element 210 adjoining the under side 232 of the working edge 230 are likewise coated with a coating 250 in the case of the second lamellar doctor blade 200 .
[0131] The second coating consists of a nickel-phosphorus alloy containing a mixed-in alloying component in the form of tungsten (W). The phosphorus content is, for example, 10% by weight and the proportion of tungsten is, for example, 5% by weight, in each case based on the total weight of the coating 250 . The layer thickness of the coating 250 in the region of the working edge 130 is, for example, 15 μm, while the hardness is, for example, 1200 HV.
[0132] FIG. 3 shows a third lamellar doctor blade 300 according to the invention in cross section. The third doctor blade 300 has a base element 310 which in the region of the working edge 330 is coated with a first coating 350 in the same way as the first doctor blade in FIG. 1 . Correspondingly, the upper side 331 of the working edge 330 , the transition region 325 and an adjoining subregion of the upper side 321 of the rear region 320 of the base element 310 and also the front face 340 , the under side 332 of the working edge 330 and a subregion of the underside 322 of the rear region 320 of the base element 310 adjoining the under side 332 of the working edge 330 are coated with the coating 350 .
[0133] The first coating 350 of the third lamellar doctor blade 300 has the same composition and structure as the coating 150 of the first lamellar doctor blade 100 and contains corresponding hard material particles 360 , e.g. particles of silicon carbide.
[0134] In addition, the third lamellar doctor blade has a second coating 370 which completely surrounds the lamellar doctor blade 300 . In other words, the second coating 370 completely covers both the first coating 350 and the upper side 321 and also the under side 322 of the rear region 320 of the base element 310 .
[0135] The second coating 370 is, for example, formed by an electrochemically deposited nickel layer having a thickness of, for example, about 2 μm. The second coating 370 consists, except for unavoidable impurities, exclusively of nickel in the present case.
[0136] FIG. 4 shows a fourth lamellar doctor blade 400 in cross section. The fourth lamellar doctor blade 400 has essentially the same construction as the third lamellar doctor blade from FIG. 3 . However, in contrast to the third doctor blade 300 , the fourth doctor blade 400 has a second coating 470 which only covers the first coating 450 . The second coating 470 thus surrounds only the upper side 431 of the working edge 430 , the transition region 425 and an adjoining subregion of the upper side 421 of the rear region 420 of the base element 410 and also the front face 440 , the under side 432 of the working edge 430 and a subregion of the under side 422 of the rear region 420 of the base element 410 adjoining the under side 432 of the working edge 430 . The rear region 420 of the base element 410 is accordingly bare and covered neither with the first coating 450 nor with the second coating 470 .
[0137] In the region of the upper side 421 and the under side 422 of the rear region 420 , the layer thickness of the second coating 470 decreases continuously, so that the second coating 470 runs to its end in the form of a wedge in a direction away from the working edge 470 .
[0138] FIG. 5 depicts a fifth lamellar doctor blade 500 according to the invention in cross section. The base element 510 having the rear end 520 and the working edge 530 has essentially the same construction as the lamellar doctor blade 300 from FIG. 3 . The fifth doctor blade 500 likewise has a first coating 550 which is configured in the same way as the coating 350 of the third doctor blade 300 . Correspondingly, the first coating 550 of the fifth doctor blade 500 covers the upper side 531 of the working edge 530 , the transition region 525 and an adjoining subregion of the upper side 521 of the rear region 520 of the base element 510 and also the front face 540 , the under side 532 of the working edge 530 and a subregion of the under side 522 of the rear region 520 of the base element 510 adjoining the under side 532 of the working edge 530 .
[0139] As in the case of the third lamellar doctor blade 300 , the fifth doctor blade 500 also has a second coating 570 which completely surrounds the lamellar doctor blade 500 , so that the second coating 570 completely surrounds the first coating 550 , the upper side 521 and also the under side 522 of the rear region 520 of the base element 410 . In contrast to the second coating 370 of the third doctor blade, the second coating 570 of the fifth doctor blade 500 has a two-layer structure. The second coating 570 has a primer layer 571 which has been applied electrochemically directly onto the first coating 550 and the rear region 520 of the base element 510 and consists, except for unavoidable impurities, exclusively of pure nickel. The thickness of the primer layer 571 is, for example, about 0.5 μm. The covering layer 572 applied on top of the primer layer 571 likewise consists of electrochemically deposited pure nickel which, however, is additionally admixed with saccharin. The layer thickness of the second coating 570 , i.e. the layer thickness of the primer layer 571 and the layer thickness of the covering layer 572 , in the region of the working edge 530 is, for example, about 4 μm, while the layer thickness in the rear region 520 is, for example, about 2 μm.
[0140] FIG. 6 shows a sixth lamellar doctor blade 600 in cross section. The base element 610 having the rear region 620 and the working edge 630 provided with a first coating 650 have essentially the same construction as the third doctor blade 300 from FIG. 3 . In contrast to the third doctor blade 300 from FIG. 2 , the second coating 670 , which completely surrounds the sixth doctor blade 600 , consists of a nickel-phosphorus alloy which has been deposited by an electroless method and contains lubricating particles 680 of hexagonal boron nitride (hex-BN) dispersed therein. The phosphorus content of the second coating 670 is, for example, 7% by weight, while the thickness of the second coating is about 2 μm. The lubricating particles 680 have a particle size of about 100 nm and a proportion by volume of about 17%.
[0141] FIG. 7 shows a seventh lamellar doctor blade 700 which represents a variant of the sixth doctor blade 600 from FIG. 6 , in cross section. The arrangement of the first coating 750 and the second coating 770 on the base element 710 of the seventh doctor blade 700 is essentially the same as in the sixth doctor blade 600 from FIG. 6 . However, the sixth doctor blade 600 and the seventh doctor blade 700 differ in terms of the composition of the coatings.
[0142] The first coating 750 of the seventh doctor blade 700 which essentially surrounds the working edge 730 , is based on a nickel-phosphorus alloy which has been deposited by an electroless method and contains a first additive component in the form of mixed-in tungsten (W). In other words, the first coating 750 is thus based on a nickel-phosphorus-tungsten alloy. The layer thickness of the first coating 750 in the region of the working edge 730 is, for example, about 12 μm and the phosphorus content is about 12% by weight. In addition, further additive components in the form of a first hard material component 760 and a second hard material component 761 are dispersed in the first coating 750 . The first hard material component 760 is, for example, diamond particles having a particle size of, for example, 100-200 nm and a proportion by volume of about 10%. The second hard material component consists, for example, of silicon carbide (SiC) having a particle size of 1.5-2.0 μm and a proportion by volume of about 10%. The particle size of the second hard material component 761 (SiC) is thus greater than the particle size of the first hard material component 760 (diamond). The hardness of the first coating 750 is about 1300 HV.
[0143] The second coating 770 , which completely surrounds the seventh doctor blade 700 , is based, for example, on a nickel-phosphorus alloy which has been deposited by an electroless method and contains lubricating particles 780 of hexagonal BN (hex-BN) dispersed therein. The phosphorus content of the second coating is about 6% by weight while the layer thickness is about 2 μm and the proportion by volume of the lubricating particles 780 is about 18%. The particle size of the lubricating particles 780 is about 100 nm. The phosphorus content of the nickel-phosphorus alloy of the second coating 770 is thus lower than the phosphorus content of the nickel-phosphorus alloy of the first coating 750 .
[0144] The above-described lamellar doctor blades shown in FIGS. 1-7 are merely illustrative examples of many embodiments which can be realized. Further specific embodiments are shown in Table 1 below. To aid understanding of the table: the abbreviation “Chem. Ni—P” is a nickel-phosphorus alloy deposited chemically or in an electroless manner. Correspondingly, the abbreviation “Elect.” means electrochemically deposited and “Elect. Ni—P” refers to an electrochemically deposited nickel-phosphorus alloy. “P content” is the phosphorus content of a nickel-phosphorus alloy.
[0000]
TABLE 1
1st coating
2nd coating
Additive
Additive
component
component
Particle
Particle
size
Basis
size
Basis
Proportion
P
Proportion
P content
by
content
by
No.
Thickness
volume
Thickness
volume
A
Chem. Ni—P
SiC
none
none
(FIG. 1)
9%
1.6 μm
15 μm
16%
B
Chem. Ni—P
TiC
none
none
12%
1.9 μm
25 μm
20%
C
Chem. Ni—P
WC
none
none
8%
1.8 μm
25 μm
15%
D
Chem. Ni—P
cubic BN
none
none
8%
1.8 μm
25 μm
15%
E
Chem. Ni—P
cubic B 4 C
none
none
8%
1.8 μm
25 μm
15%
F
Chem. Ni—P
molybdenum
none
none
10%
(particle)
10 μm
1.5 μm
17%
G
Chem. Ni—P
hexagonal
none
none
8%
BN
20 μm
1.8 μm
15%
H
Chem. Ni—P
Tungsten
none
none
(FIG. 2)
10%
none,
15 μm
since alloy
5%
I (FIG. 3)
Chem. Ni—P
SiC
Elect.
9%
1.6 μm
nickel
15 μm
16%
0%
2 μm
J
Chem. Ni—P
Al 2 O 3
Elect.
none
9%
1.6 μm
nickel
15 μm
16%
0%
2 μm
K
Chem. Ni—P
SiC
Elect.
none
(FIG. 5)
9%
1.6 μm
nickel
15 μm
16%
(primer
layer/
covering
layer
containing
saccharin)
0%
2-4 μm
L
Chem. Ni—P
SiC
Elect.
none
9%
1.6 μm
Ni—P
15 μm
16%
13%
2 μm
M
Chem. Ni—P
Al 2 O 3
Elect.
none
9%
1.6 μm
Ni—P
15 μm
16%
13%
2 μm
N
Chem. Ni—P
SiC
Chem. Ni—P
Hexagonal
(FIG. 6)
9%
1.6 μm
7%
BN
15 μm
16%
2 μm
100 nm
17%
O
Chem. Ni—P
SiC
Chem. Ni—P
cubic BN
9%
1.6 μm
6%
1.5 μm
15 μm
16%
2 μm
18%
P
Chem. Ni—P
Tungsten
Chem. Ni—P
hexagonal
(FIG. 7)
12%
none,
6%
BN
12 μm
since
2 μm
100 nm
alloy
18%
5%
SiC
1.5 μm
10%
Diamond
150 nm
10%
[0145] The embodiment denoted by “A” in the table corresponds to the first lamellar doctor blade 100 depicted in FIG. 1 . The embodiments “B”-“G” refer to the indicated and sometimes different additive components, particle sizes, proportion by volume and/or layer thicknesses of a structure analogous to the lamellar doctor blade 100 .
[0146] The embodiment denoted by “H” corresponds to the second lamellar doctor blade 200 of FIG. 2 , while the embodiment denoted by “I” corresponds to the third lamellar doctor blade 300 of FIG. 3 . The embodiment “J” is of essentially the same construction as the third lamellar doctor blade 300 of FIG. 3 except for the different additive component in the first coating.
[0147] The lamellar doctor blade 500 depicted in FIG. 5 is denoted as embodiment “K” in the table and accordingly has a two-layer electrochemically deposited second coating based on nickel. The embodiments “L” and “M” represent variants of the embodiment “K” which instead of the second coating based on nickel have a second coating in the form of an electrochemically deposited nickel-phosphorus alloy.
[0148] The embodiment “N” corresponds to the sixth lamellar doctor blade 600 depicted in FIG. 6 . Embodiment “O” differs from the embodiment “N” in that, in particular, it contains cubic boron nitrode (cub-BN) instead of hexagonal boron nitride (hex-BN) in the second coating. It should be noted that the particle size of the cubic boron nitride is substantially greater than the particle size of the hexagonal boron nitride.
[0149] Finally, embodiment “P” corresponds to the seventh lamellar doctor blade 700 in FIG. 7 .
[0150] FIG. 8 illustrates a process 800 for producing a lamellar doctor blade as depicted, for example, in FIG. 5 . Here, in a first step 801 , the working edge 530 of the base element 510 to be coated with the nickel-phosphorus alloy or the first coating 550 is, for example, dipped into a suitable aqueous electrolyte bath known per se containing hard material particles 560 suspended therein, with nickel ions from a nickel salt, e.g. nickel sulfate, being reduced to elemental nickel by means of a reducing agent, e.g. sodium hypophosphite, in an aqueous environment and being deposited on the working edge 530 to form a nickel-phosphorus alloy and at the same time embed the hard material particles 560 . This occurs without application of an electric potential and completely without an external electric current under highly acidic conditions (pH 4-6.5) and at elevated temperatures of, for example, 70-95° C.
[0151] In a second step 802 , for example, a first electrochemical electrolyte bath based on water containing nickel chloride and hydrochloric acid and having a pH of about 1 is initially charged. The base element 510 with the first coating 550 applied in the first step is immersed completely in the electrolyte bath and a primer layer 571 of the second coating 570 is deposited in a manner known per se by means of an external electric current. A covering layer 572 is subsequently deposited in a manner known per se in a second electrochemical electrolyte bath based on water containing nickel, nickel sulfate, nickel chloride, boric acid and saccharin at a pH of 3.7.
[0152] In a third step 803 , the base element 510 provided with the first coating 550 and the second coating 570 is subjected to a heat treatment at a temperature of 300° C. for, for example, two hours. Finally, the finished lamellar doctor blade 500 is cooled and is thus ready to use.
[0153] If a doctor blade without a second coating is produced, the second step 802 is omitted and the third step is correspondingly carried out without the second coating. To produce a doctor blade which has a second coating based on a nickel-phosphorus alloy deposited by an electroless method, coating analogous to the first step 801 is carried out in the second step 802 . If tungsten (W) is provided as additive component for improving the wear behavior, deposition of the respective coating as per the first step 801 follows, in particular at a pH of 8-9.
[0154] As tests have shown, the lamellar doctor blades 100 , 200 , 300 , 400 , 500 , 600 , 700 depicted in FIGS. 1-7 and the lamellar doctor blades additionally shown in Table 1 have a very high wear resistance and stability and make extremely precise scraping-off, in particular of printing ink, possible. The latter is the case over the entire life of the doctor blades.
[0155] For comparison, a base element identical to that of the lamellar doctor blade 100 from FIG. 1 was, in a first comparative experiment, provided only with a first coating composed of a pure nickel-phosphorus alloy in the region of the working edge, with the additive component for increasing the wear resistance in the form of the hard material particles of SiC being dispensed with. As has been found, such doctor blades have a significantly poorer wear resistance and stability than the doctor blades shown in FIGS. 1-7 .
[0156] In further tests, the additive components for improving the wear behavior were in each case left out in the lamellar doctor blades 300 , 500 , 600 , 700 from FIGS. 3 , 5 , 6 and 7 . Such doctor blades, too, have a significantly poorer wear resistance than the doctor blades shown in FIGS. 3 , 5 , 6 and 7 .
[0157] The above-described embodiments and the production process are merely illustrative examples which can be modified as desired within the scope of the invention.
[0158] Thus, the base elements 110 , 210 , 310 , 410 , 510 , 610 , 710 of the doctor blades in FIGS. 1-7 can also be made of a different material, e.g. stainless steel or a carbon steel. In this case, it can be advantageous, for economic reasons, to apply the second coating only in the region of the working edges 130 , 230 , 330 , 430 , 530 , 630 , 730 in order to reduce the consumption of material for the coating. However, the base elements of the doctor blades in FIGS. 1-7 can in principle also consist of a nonmetallic material, e.g. plastics. This can, in particular, be advantageous for applications in flexographic printing.
[0159] It is also possible to use base elements having a different shape than the base elements shown in FIGS. 1-7 . In particular, the base elements can have a wedge-shaped working edge or an untapered cross section having a rounded working edge. The free front faces 140 , 240 , 340 , 440 , 540 , 640 , 740 of the working edges 130 , 230 , 330 , 430 , 530 , 630 , 730 can, for example, also be completely rounded.
[0160] Furthermore, the doctor blades of the invention in FIGS. 1-7 can also have different dimensions. Thus, for example, the thicknesses of the working regions 130 , 230 , 330 , 430 , 530 , 630 , 730 , measured from the respective upper sides 131 . . . 731 to the respective under sides 132 , 232 , . . . 732 , can vary in the range of, for example, 0.040-0.200 mm.
[0161] The coatings of the doctor blades in FIGS. 1-7 can likewise contain further alloying components and/or additional materials such as metal atoms, nonmetal atoms, inorganic compounds and/or organic compounds. The additional materials can also be particulate.
[0162] All of the doctor blades shown in FIGS. 1-7 can, for example, be coated with further coatings. The further coatings can be present in the region of the working edges and/or the rear regions and, for example, improve the wear resistance of the working edges and/or protect the rear region from attack by aggressive chemicals. In principle, these can also be coatings composed of plastics.
[0163] In the case of the doctor blade 200 from FIG. 2 , it is also possible to apply a second coating to the existing first coating 250 and introduce additive components for improving the wear behavior, e.g. particulate additive components, into the second coating.
[0164] In summary, it can be said that novel doctor blades which display extremely good wear resistance and allow uniform and streak-free scraping-off of printing ink over the entire life have been provided. At the same time, the doctor blades of the invention can be realized in a variety of embodiments, so that they can be specifically matched to specific uses.
[0165] While the method herein described, and the form of apparatus for carrying this method into effect, constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention, which is defined in the appended claims. | A doctor blade for scraping printing ink from a surface of a printing plate, comprising a flat and elongated main body having a working edge area formed in a longitudinal direction, the working edge area being coated with at least one first coating on the basis of a nickel-phosphorus alloy, and is characterized in that the first coating contains at least one additional component for improving the wear behavior of the doctor blade. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates to the field of axial fans, and more particularly to an improved means for mounting fan blades on a rotatable hub.
Axial fans are widely used to transform mechanical energy, which has been supplied to them by a motor, into displacement of air. They are used wherever it is necessary to evacuate or to feed air or any other gas.
The present invention relates to an axial fan of the type comprising a hub, a plurality of arms extending radially outwardly from the hub and blade members, each blade member being secured to its respective arm.
PRIOR ART
Axial fans are generally subjected to substantial loads which act primarily on the inner ends, i.e. the roots of the blades. The loads which act on the blades are composed mainly of the traction force, acting to push the blades in the axial direction opposite to the air flow, and the ensuing component of the centrifugal force acting to push the blades back into the direction of the air flow. Consequently, some of these loads and their variations are transmitted in the form of vibrations from the blades to their roots and to the power transmission group (hub and drive), resulting in substantial wear of the fan structure. The connection between the inner ends of the blades and the hub, therefore, is critical since it is a possible source of failure due to fatigue cracking.
Currently, a reduction of the loads acting on the blades is obtained, for example, by a method which consists of mounting the blades with a fixed inclination with respect to the plane of rotation in a direction opposite to the air flow. Such an assembly can be seen in FIG. 1, showing a blade 2 connected to a hub 1 by means of an arm 3 . The arm 3 is secured to the hub 1 by a clamping device 4 and to the blade 2 by a securing device 5 . The blade is inclined at an angle α with respect to the plane of rotation, which is the plane perpendicular to the axis of rotation AA′. The main forces acting on the blade 2 are the centrifugal force CF and the traction force TF; the direction of air flow is indicated by the arrow AF.
As a result of the fixed inclination of the blades, loads can only be neutralised if the fan operates precisely in the conditions predicted by the original calculation, i.e. at a predetermined and constant speed of rotation.
Another prior art method proposes to connect the hub to the roots of the blades by a hinge, thereby enabling the blades to float when the fan is in operation. Such an assembly can be seen in FIG. 2 where, similarly to FIG. 1, there is shown a blade 2 connected to a hub 1 by means of an arm 3 ′. The arm 3 ′ is secured to the hub 1 by a clamping device 4 and to the blade 2 by a securing device 5 . The main forces acting on the blade 2 are the centrifugal force CF and the traction force TF; the direction of air flow is indicated by the arrow AF. Numeral 6 designates a hinge providing a non-rigid connection between the blade 2 and the hub 1 . Since both parts of the hinge are movable with respect to each other, both parts are exposed to wear and need frequent maintenance. Furthermore, the gap between the two parts of the hinge provides a space for the penetration of corrosive elements or the formation of deposits that ultimately could impede the relative movement of both parts of the hinge, preventing them from fulfilling their function of neutralising traction and centrifugal forces acting on the blades.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an axial fan with a simple structure, wherein the load variations and the ensuing vibrations are substantially reduced.
In accordance with the present invention, this object is achieved by providing an axial fan of the type comprising a hub, a plurality of arms extending radially outwardly from the hub and blade members, each blade member being secured to its respective arm, characterised in that the arms consist of flexible elements with a bending stiffness such that, in operation, the blade members are inclined at an angle at which the centrifugal forces acting on the blade members neutralise the traction forces acting on same.
In an axial fan according to the present invention, the flexible elements are sized according to the operational requirements of the fan in such a way that, when the fan is in use, the blades adjust to a position where the bending moment generated by the traction forces TF is neutralised by the opposite bending moment generated by the centrifugal forces CF. Consequently, the loads acting on the roots of the blades tend to cancel each other out and, at the same time, the load variations and ensuing vibrations transmitted from the blades to the power transmission group are substantially reduced, thereby increasing the service life of the fan blades and the drive mechanism. The fan of the present invention has a higher resistance to fatigue than the fan of the prior art.
A reduction in the vibrations of the blades, as obtained by the present invention, allows the design of fan blades using less valuable materials, thinner materials, or a combination of both, which constitutes a further advantage of the invention.
DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example and with reference to the accompanying drawings, where:
FIG. 1 shows a side view of a first example of an axial fan according to the prior art;
FIG. 2 shows a side view of a second example of an axial fan according to the prior art;
FIG. 3 a shows a side view and FIG. 3 b a top view of an axial fan according to a first embodiment of the invention, wherein the flexible element is secured to the root of the blade;
FIG. 4 a shows a side view and FIG. 4 b a top view of an axial fan according to a second embodiment of the invention, wherein the blade member is a hollow blade and the flexible element is secured on the inside of the hollow blade;
FIG. 5 a shows a side view and FIG. 5 b a top view of an axial fan according to a third embodiment of the invention, wherein the flexible element is secured to the blade.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 3 ( 3 a , 3 b ) shows a first embodiment of the invention, where the axial fan comprises a plurality of blade members 12 connected to the hub 1 by means of flexible elements 7 . Each flexible element 7 is secured to the hub 1 by a clamping device 4 (not further described herein since it is already known) and to the blade member 12 by a securing device 5 (not further described herein since it is already known). As explained above in connection with the prior art fans, it is of advantage that the blade member 12 is mounted at an angle α with respect to the plane of rotation, which is the plane perpendicular to the axis of rotation AA′. The main forces acting on the blade member 12 are the centrifugal force CF and the traction force TF; the direction of air flow is indicated by the arrow AF.
A flexible element 7 preferably has an aerodynamic cross-section, for example a circular cross-section, but it may however be designed as a number of different shapes, as long as it fulfils its function of bending in order to compensate the opposing loads on the blade member 12 .
The materials used in the manufacture of a flexible elements 7 may, for example, consist of fibre-reinforced resins, which are known to have an elastic modulus allowing them to bend substantially, even when submitted to small loads.
Other materials such as laminated structures can be used for a flexible elements 7 . These laminated structures can be provided at both extremities with end portions matching corresponding portions on the blade members 12 and on the hub 1 . Preferably these end portions are formed as integral parts of the laminated structure. Alternatively, the blade members 12 consist of a laminated structure whereby the flexible elements 7 form an integral part of the blade members 7 .
In a second embodiment of the invention, shown in FIG. 4, an axial fan comprises a plurality of blade members 12 ′ of an airfoil type connected to the hub 1 by means of flexible elements 7 . Airfoil type blade members typically consist of sheets bent into an airfoil shape forming an aerodynamic profile with a hollow structure.
This allows the flexible element 7 to be secured to the blade member 12 ′ on the inside thereof within the hollow structure, as can be seen in FIG. 4, where the flexible element 7 is secured to the blade member 12 ′ by a securing device 5 and to the hub 1 by a clamping device 4 . As explained above in connection with the prior art fans, it is of advantage that the blade member 12 ′ is mounted at an angle α with respect to the plane of rotation, which is the plane perpendicular to the axis of rotation AA′. The main forces acting on the blade member are the centrifugal force CF and the traction force TF; the direction of air flow is indicated by the arrow AF.
If it is not necessary to have blade members ( 12 , 12 ′) mounted at a variable angle a with respect to the plane of rotation, a laminar flexible element 7 may be used, fixed directly onto the hub 1 .
If it is desired to increase the angle of inclination a of a blade member 12 ′ of an airfoil type with low loads, the flexible element 7 is extended inside the blade member 12 ′ and is then fixed further outside: when the fan is running, to avoid interference between the blade member 12 ′ (which is more rigid) and the flexible element 7 , the two parts are sized in such a way that the necessary space is left between them.
On the embodiments shown by way of example by FIGS. 3 and 4, one extremity of the flexible element 7 is supported by the clamping device 4 which is rigidly fixed to the hub 1 of the fan, while the other extremity of the flexible element 7 is fixed to the body of the blade members ( 12 , 12 ′): said embodiments are not suitable for being advantageously used if it is necessary to have blade members ( 12 , 12 ′) mounted at a variable angle a with respect to the plane of rotation of the fan.
In fact, for the correct working of the flexible element 7 (composed normally of a laminar shaped body) it is necessary that the flexible element 7 be stimulated to perform (almost) exclusively a bend at a right angle to the plane of rotation of the fan, that is that the larger side of the flexible element 7 should lie (as far as possible) in the plane of rotation of the fan.
When (in the embodiments in FIGS. 3 and 4) the angle α with respect to the plane of rotation at which the blade members ( 12 , 12 ′) are mounted is varied, the flexible element 7 integral with the blade member ( 12 , 12 ′) is also turned, the larger side of the flexible element 7 no longer lies in the plane of rotation of the fan and is therefore stressed by the air flow AF: this leads to an increase in the bending stiffness of the flexible element 7 which (even if and when it does not “load” the flexible element 7 to breakage) does not allow the flexible element 7 to “work” as desired.
FIGS. 5 ( 5 a , 5 b ) shows a further embodiment of the invention, suitable for being advantageously used for blade members ( 12 , 12 ′) mounted at a variable angle α with respect to the plane of rotation of the fan, which differs from the ones illustrated in FIGS. 3 and 4 essentially due to the fact that one extremity of the flexible element 7 is rigidly fixed to the hub 1 of the fan while the other extremity of the flexible element 7 is fixed to a clamping device 4 which supports the root area of the blade members ( 12 , 12 ′): the larger side of the flexible element 7 always lies in the plane of rotation of the fan (the flexible element 7 therefore “works” or can “work” always in an optimum manner), while (acting on the clamping device 4 ) the angle α with respect to the plane of rotation at which the blade members ( 12 , 12 ′) are mounted may be modified as requires by the specific application without this involving a rotation of the flexible element 7 , which is no longer integral with the blade members ( 12 , 12 ′).
When the fan is stationary, the weight of the blade members ( 12 , 12 ′) and the bending stiffness of the flexible elements 7 may be such that the blade members ( 12 , 12 ′) incline excessively or to an extent that they interfere with other elements of the fan.
In such cases a supporting element (not shown) which is fixed to the hub can be provided in order to support the blade members.
This supporting element can be for example a simple disc. | The present invention relates to an axial fan of the type comprising a hub, a plurality of arms extending radially outwardly from the hub and blade members, each blade member being secured to its respective arm, wherein the arms consist of flexible elements with a bending stiffness such that, in operation, the blade members are inclined at an angle at which the centrifugal forces acting on the blade members neutralize the traction forces acting on same.
The load variations and ensuing vibrations are thus substantially reduced, thereby increasing the service life of the fan blades and the drive mechanism. | 5 |
BACKGROUND OF THE INVENTION
The invention relates to an improved extended nip press and more particularly to a pressing mechanism for extracting water from a traveling web which requires considerably less space and is capable of extracting more water from the web than has been heretofore possible with conventional press couples.
The present invention provides a pressing arrangement having a plurality of nips wherein the residence time of the web in the nips is increased over that of a roll couple and wherein a mechanically more compact structure is used. Attempts have been made to provide presses which provide for a greater pressing time and reduce the space required by the press, but a number of these have encountered disadvantages, and the present structure provides advantages over structures heretofore available.
As will be appreciated from the teachings of the disclosure, the features of the invention may be employed in the dewatering of other forms of webs than a paper web in a paper making machine. However, for convenience, a preferred embodiment of the invention will be described in the environment of a paper making machine which conventionally forms a web by depositing a slurry of pulp fibers on a traveling fourdrinier wire, transfers the web to a press section where the web passes through a number of press nips formed between roll couples, and the web then passes over a series of heated dryer drums and usually through a calendar and then is wound on the roll. The present structure forms the entire press section and takes the place of other forms of press sections heretofore available. Modifications can be made in the overall machine, as to the forming section, or the dryer section which can be accommodated by the instant invention. The structure of the instant disclosure also may be employed in pressing webs of various synthetic fibers.
The present invention relates to improvements for the press sections of a paper making machine. Because of various inherent limitations in the operation of roll couples forming press nips for the press section in a conventional paper making machine, only a given amount of water can be removed in each nip and, therefore, in a conventional paper making machine, a series of nips are usually employed. It has been found impractical to attempt to remove a significant amount of additional water by increasing the number of press nips, although the further removal of water by pressing can greatly reduce the expense and size of the dryer section. It is estimated that if the water removed in the press section can be increased to decrease the moisture from 60 percent to 50 percent, the length of the dryer section can be reduced by 1/3. This is significant in a typical 3000 feet per minute newsprint machine which employs on the order of 100 dryer drums. This significance can be appreciated in considering that the dryer drums are each expensive to construct and to operate and require the provision of steam fittings and a supply of steam for each drum. The relative importance of the removal of water in the press section is further highlighted by the fact that one of the most important economic considerations in justifying a satisfactory return on investment in the operation of a paper making machine is to obtain the highest speed possible consistent with good paper formation and better pressing will shorten the necessary time in the dryer section and permit higher speeds.
It is accordingly an object of the present invention to provide an improvement in the press section of a paper machine which makes it possible to remove an increased amount of water in this press section and makes it possible to provide a press section having a relatively compact or shortened pressing area of a unique elongated or extended nature which does not have the performance limitations of conventional roll couple presses and which requires far less space in terms of requirements as to the overall length of the press section. By increasing the amount of water removed from the web in the press section, increased speeds are possible with existing equipment, i.e., a given length of dryer section can operate at higher speeds since it is required to remove less water. Also, new equipment can be constructed requiring less machine length and expense.
It is an object of the present invention to provide a press using a traveling belt wherein an improved structure is employed for applying the nip loading pressure to the belt.
A further object of the invention is to provide an improved pressing mechanism for a press which counteracts the disadvantageous effects of friction and provides a press which has a uniquely long operating life.
Another object of the invention is to provide a press mechanism wherein pressures at stages along the nip are more easily controlled than in structures heretofore available.
Another object of the invention is to provide a press which avoids the disadvantages of excessive leakage and the difficulty of providing large sliding seals as contrasted with prior art liquid pressure presses.
Other objects, advantages and features will become more apparent with the disclosure of the principles of the invention and as will be seen, equivalent structures and methods may be employed within the principles and scope of the invention as taught in connection with the description and disclosure of the specification, claims and drawings, in which:
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view shown in somewhat schematic form of a structure embodying the principles of the present invention; .[.and.].
FIG. 2 is a fragmentary sectional view taken substantially along line II--II of FIG. 1.[...]..Iadd.; and
FIG. 3 is a side elevational view shown in somewhat schematic form of an alternate structure. .Iaddend.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As illustrated in FIG. 1, a backing roll 9 is wrapped with a looped belt 10 to form an extended pressing nip. In operation, a continuous traveling web W is passed through the nip along with a felt F for receiving liquid pressed from the web. The belt 10 is carried on rolls 11, 12, 13 and 14.
Pressure in the nip is obtained from a series of sliding shoes 16, 17 and 18 which may be termed slipper bearing shoes and which have a smooth lower surface extending across the belt coextensive therewith with the surface also extending in the direction of the belt travel to apply pressure to the belt which pressure is transmitted to the web. Each of the shoes 16, 17 and 18 have a concave arcuately shaped lower surface with a relieved leading edge so as to form a wedge of lubricating fluid between them and the belt. For providing this lubricating fluid, a supply line 19 is provided to keep fluid within a housing 20 which has sliding seals against the belt to prevent the escape of lubricant which could result in the contamination of the web. Each of the shoes should have a radius of approximately the same as the roll and should be curved in such a direction so as to fit the roll. An objective is to get as much length of pressure as possible to form an extended pressing nip at each of the shoes.
The shoes are pivotally supported shown at 21, 27 and 30 .Iadd.supporting the shoes and accommodating movement of each shoe about an axis parallel to the axis of the roll 9.Iaddend.. The shoes are somewhat flexible over their entire length and are backed by hydraulic fluid such as so that they exert a uniform pressure against the belt along their length thereby pressing water uniformly from the web along the length of the roll.
The pivotal supports 21, 27 and 30 may be in the form of a roll pin as shown in FIG. 2 which is supported from a piston 22 in a cylinder 23 containing a pressurized fluid. The piston 22 is sufficiently flexible over its length so that with the fluid in the cylinder 23 being at uniform pressure along the length of the cylinder in accordance with Pascal's law, the shoe 16 will exert uniform pressure along the length of the roll 9. This will occur even though the downward load on the roll 9 will cause downward bending thereof.
The support for each of the shoes is similar in construction and, therefore, only details for the first shoe 16 need be shown. The shoe 17 has its roll pin 27 carried on a piston 28 supported in a cylinder 29. Shoe 18 has its roll pin 30 supported on a piston 31 carried in a cylinder 32. Each of the cylinders are supported in an overhead support beam 15. This beam will also bend upwardly with a pressure in the cylinders 23, 29 and 32, but this will not affect the application of uniform pressure by the shoes to the belt.
If a relatively wide web is expected so that it is necessary to provide a long roll 9, anti-deflection means may be provided for the roll to prevent excessive bending. Such anti-deflection means may take various forms, and in one form the roll 9 will be a hollow roll shell with a stationary shaft extending therethrough. Fluid force transfer means will be located between the roll shell and the shaft to transfer the load from the shell to the shaft with the shaft bending downwardly relative to the roll shell, and the roll shell maintained substantially axially straight. The fluid force transmission means may take various forms such as that shown in the Justus Pat. 3,119,324.
As the web enters the nip, it is subjected first to the pressure applied by the shoe 16, and then subsequently to the pressure supplied by the shoe 17 and thereafter by the pressure applied to the shoe 18. Larger number of shoes may be provided. The shoes may be controlled to give sequentially increasing pressures to the web by pressurizing the chambers 23, 29 and 32 with sequentially greater pressures. In another form the same fluid pressure may be applied to each of the chambers, but the chambers may be of increasing width, so that the total pressure applied to the web through the shoes will increase. However, in a preferred form by positioning pressure control valves 24a, 25a and 26a in the lines 24, 25, and 26 leading to the cylinders 23, 29 and 32, controlled pressures may be applied. While the shoes are preferably of the same length, it is contemplated that different length shoes can be employed, such as by making the first shoe of longer length to obtain a reduced unit pressure in the first zone beneath the first shoe and successive increasing unit pressures in subsequent zones.
At the high speeds at which webs travel in current paper making machines, there is a limit to how much water can be removed at the location of the first shoe 16 inasmuch as hydraulic resistance pressures will build up within the web. In other words, as the pressure is applied very rapidly and suddenly, the water does not have adequate time to escape if the pressure applied is too high, so that a crushing or disturbance of the fibers will occur. Therefore, the pressure which is applied at the first shoe 16 is predetermined at a level so that maximum water removal will be attained without the hydraulic crushing of the web. The pressure which is applied to the next shoe 17 can be higher since some of the water will have been removed at the first shoe. Similarly, the pressure of the third shoe 18 can be still higher. This procedure is commonly followed in regular press nips where each subsequent nip applies a higher pressure. However, an advantage is obtained in the present arrangement in that a broader pressing area is employed, so that the water has more time to travel from the web into the felt. With a conventional press nip, the width of the nip is determined by the diameter of the press rolls, and this cannot be changed. By increasing the length of the shoe 19, the length of time that the web is subjected to the pressing pressure can be increased.
The present arrangement also provides an advantage over conventional press nips in that the pressure is applied hydraulically, that is, by virtue of the layer of lubricating fluid which is built up between the shoe 16 and the belt 10. This lubricating liquid has a pressure profile which builds up from the leading edge of the shoe and then drops off at the trailing edge of the shoe, but pressure extends along the full length of the shoe. This will result in improved application of pressure and improved water removal from the web as compared with the pressure profile which occurs to a web passing through the usual two roll press couple. Also, the need for web handling between subsequent press nips, as must be done in a conventional paper making machine employing the usual press couples, is eliminated since the web is under complete control from one shoe to the next. This eliminates web vibration and possible tear and, of course, greatly reduces the space requirements of a press section.
Another modification which may be made in the structure illustrated is that the roll 9 may be an open roll with circumferential surface grooves across its length, or may be in the form of a suction roll. In this arrangement the felt will be positioned against the roll and the web will be carried on top of the felt adjacent the belt.
It is also contemplated in some constructions that a pair of parallel belts may be employed with similar shoes positioned within the lower belt in opposing relation to the upper shoes. .Iadd.An example of this structure is illustrated in FIG. 3, which has a rotatable roll 9', upper and lower looped flexible impervious belts 10' and 10" respectively, which are wrapped over an upper and a lower arc of the roll respectively and form a pressure nip for receiving and dewatering portions W' and W" of the web which moves in the direction indicated by the arrowed lines wrapping the roll 9' between the pressure nips. Felts F' and F" travel through the nips with the webs, and the upper press mechanism includes sliding shoes 16', 17' and 18' having an arcuately shaped concave smooth surface and extend transversely across the roll and have a controllable fluid pressure means 22', 28' and 31' respectively for the shoes, which are pivotally supported on the fluid pressure means. A spout means 19' is provided for providing a film of lubricating fluid between the shoes and the belt. The lower press portion has smooth arcuately shaped shoes 16", 17" and 18" extending transversely along the roll, and these are in sliding engagement with the belt in a position at the side of the roll 9' opposite to the shoes 16', 17' and 18' and are in opposing relationship to the shoes 16', 17' and 18'. The shoes 16", 17" and 18" are pressed toward the belt 10" with a predetermined force by force means 22", 18" and 31", which are essentially the same in construction as the force means 22', 28' and 31'. The mechanism for the upper and lower press portion assembly is substantially the same and is substantially the same as the mechanism of FIG. 1 and is numbered similarly and need not be described in detail. Means 19" is provided for supplying a film of lubricating fluid between the shoes 16", 17" and 18" and the belt 10". There is linear tension in the belts 10' and 10", and the structure includes means for providing this linear tension for increasing the force of the belt against the web to increase the dewatering pressure such as by a structure for adjusting the rolls 12' and 12" outwardly as indicated schematically by the arrowed lines within the circles schematically indicating these rolls 12' and 12". The structure may include a second felt F-2 which sandwiches the web between this second felt and the first felts F' and F" so that the web is carried between the felts between the belt and roll. The roll 9' may be an open roll as indicated by the dotted lines 9" on the roll. .Iaddend.This will eliminate the need for providing anti-deflection means for the lower roll, but because of the necessity of providing additional shoes and additional equipment, the illustrated arrangement is preferred.
It is further contemplated that a tension may be applied to the belt which will aid in the application of pressure to the web during its entire travel through the nip. This continuing pressure between the shoes may reduce rewetting, that is, return travel of the moisture from the felt to the web. It also may be desirable in some installations to utilize two felts with the web sandwiched therebetween, so that one felt passes against the belt and another felt passes against the cutter surface of the roll 9. The belt 10 will travel due to its contact with the felt and the driving forces of the roll, or in some instances, a separate drive for the belt may be employed to drive it at substantially the speed of the outer surface of the roll 9. | A press mechanism for removing liquid from a traveling fibrous web such as a web of paper received from the fourdrinier section of a paper machine including a backing roll and a looped traveling belt forming a press nip with the roll with a plurality of shaped shoes extending the length of the roll and pressing the belt toward the nip with said shoes having a concave curved surface facing the belt and being pivotally supported so that a wedge of lubricating fluid builds up between each of the shoes and the belt to lubricate the shoes and to press the belt toward the nip. Means are provided for individually controlling the force with which the shoes are pressed toward the belt. | 3 |
CROSS-REFERENCES TO RELATED APPLICATIONS
The present application is a divisional of U.S. patent application Ser. No. 09/231,851, filed Jan. 14, 1999, now U.S. Pat. No. 6,475,134 which was a continuation-in-part of U.S. patent application Ser. No. 08/582,301, filed Jan. 3, 1996, and issued as U.S. Pat. No. 5,800,336, which was a continuation-in-part of U.S. patent application Ser. No. 08/568,006, filed Dec. 6, 1995, and issued as U.S. Pat. No. 5,913,815, which was a continuation-in-part of U.S. patent application Ser. No. 08/368,219, filed Jan. 3, 1995, and issued as U.S. Pat. No. 5,624,376, which was a continuation-in-part of U.S. patent application Ser. No. 08/225,153, filed on Apr. 8, 1994, and issued as U.S. Pat. No. 5,554,096) and which was a continuation-in-part U.S. patent application Ser. No. 08/087,618, and issued as U.S. Pat. No. 5,456,654, filed on Jul. 1, 1993. The full disclosures of each of these applications is hereby incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
The present invention relates to the field of assisting hearing in persons and particularly to the field of transducers for producing vibrations in the inner ear.
The seemingly simple act of hearing is a task that can easily be taken for granted. The hearing mechanism is a complex system of levers, membranes, fluid reservoirs, neurons and hair cells which must all work together in order to deliver nervous stimuli to the brain where this information is compiled into the higher level perception we think of as sound.
As the human hearing system encompasses a complicated mix of acoustic, mechanical and neurological systems, there is ample opportunity for something to go wrong. Unfortunately this is often the case. It is estimated that one out of every ten people suffer some form of hearing loss. Surprisingly, many patients who suffer from hearing loss take no action in the form of treatment for the condition. In many ways, hearing is becoming more important as the pace of life and decision making increases as we move toward an information based society. Unfortunately for the hearing impaired, success in many professional and social situations may be becoming more dependent on effective hearing.
Various types of hearing aids have been developed to restore or improve hearing for the hearing impaired. With conventional hearing aids, sound is detected by a microphone, amplified using amplification circuitry, and transmitted in the form of acoustical energy by a speaker or another type of transducer into the middle ear by way of the tympanic membrane. Often the acoustical energy delivered by the speaker is detected by the microphone, causing a high pitched feedback whistle. Moreover, the amplified sound produced by conventional hearing aids normally includes a significant amount of distortion.
Attempts have been made to eliminate the feedback and distortion problems associated with conventional hearing aid systems. These attempts have yielded devices which convert sound waves into electromagnetic fields having the same frequencies as the sound waves. A microphone detects the sound waves, which are both amplified and converted to an electrical current. A coil winding is held stationary by being attached to a nonvibrating structure within the middle ear. The current is delivered to the coil to generate an electromagnetic field. A separate magnet is attached to an ossicle within the middle ear so that the magnetic field of the magnet interacts with the magnetic field of the coil. The magnet vibrates in response to the interaction of the magnetic fields, causing vibration of the bones of the middle ear.
Existing electromagnetic transducers present several problems. Many are installed using complex surgical procedures which present the usual risks associated with major surgery and which also require disarticulating (disconnecting) one or more of the bones of the middle ear. Disarticulation deprives the patient of any residual hearing he or she may have had prior to surgery, placing the patient in a worsened position if the implanted device is later found to be ineffective in improving the patient's hearing.
Although the Floating Mass Transducer (FMT) developed by the present assignee is a pioneering technology that has succeeded where prior art devices have failed, improved floating mass transducers would be desirable to provide hearing assistance.
BRIEF SUMMARY OF THE INVENTION
The present invention provides an improved dual coil floating mass transducer for assisting a person's hearing. Inertial vibration of the housing of the floating mass transducer produces vibrations in the inner ear. A magnet is disposed within the housing biased by biasing mechanisms so that friction is reduced between the magnet and the interior surface of the housing. Two coils reside within grooves in the exterior of the housing which cause the magnet to vibrate when an electrical signal is applied to the coils.
With one aspect of the invention, an apparatus for improving hearing comprises: a housing; at least one coil coupled to an exterior of the housing; and a magnet positioned within the housing so that an electrical signal through the at least one coil causes the magnet to vibrate relative to the housing, wherein vibration of the magnet causes inertial vibration of the housing in order to improve hearing. Typically, a pair of oppositely wound coils are utilized.
With another aspect of the invention, a system for improving hearing comprises: an audio processor that generates electrical signals in response to ambient sounds; and a transducer electrically coupled to the audio processor comprising a housing; at least one coil coupled to an exterior of the housing; and a magnet positioned within the housing so that an electrical signal through the at least one coil causes the magnet to vibrate relative to the housing, wherein vibration of the magnet causes inertial vibration of the housing in order to improve hearing.
With another aspect of the invention, a method of manufacturing a hearing device comprises the steps of: providing a cylindrical housing; placing a magnet within the housing; biasing the magnet within the housing; sealing the housing; and wrapping at least one coil around an exterior of the housing.
Additional aspects and embodiments of the present invention will become apparent upon a perusal of the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a portion of the auditory system showing a floating mass transducer positioned for receiving electrical signals from a subcutaneous coil inductively coupled to an external audio processor positioned outside a patient's head.
FIG. 2 is a cross sectional view of an embodiment of a floating mass transducer.
FIG. 3 is a cross-sectional view of another embodiment of a floating mass transducer.
FIG. 4A shows views of a magnet and biasing mechanisms.
FIG. 4B shows a cross-sectional view of a cylindrical housing with one end open.
FIG. 4C shows a cross-sectional view of a magnet and biasing mechanisms within the cylindrical housing.
FIG. 4D shows a cross-sectional view of a magnet biased within the sealed cylindrical housing.
FIG. 4E illustrates beginning the process of wrapping a wire around a groove in the cylindrical housing.
FIG. 4F illustrates the process of wrapping the wire around the groove in the cylindrical housing.
FIG. 4G shows a cross-sectional view of crossing the wire over to another groove in the cylindrical housing.
FIG. 4H illustrates the process of wrapping the wire around the other groove in the cylindrical housing.
FIG. 4I shows a cross-sectional view of thicker leads connected to the ends of the wire wrapped around the cylindrical housing that form a pair of coils of the floating mass transducer.
FIG. 4J shows a cross-section view of the thicker leads wrapped around the cylindrical housing.
FIG. 4K shows a clip for connecting the floating mass transducer to an ossicle within the inner ear.
FIG. 4L shows the clip secured to the floating mass transducer.
FIG. 4M shows views of a floating mass transducer that is ready to be implanted in a patient.
FIGS. 4N and 4O show views of a floating mass transducer that is ready to be implanted in a patient.
FIG. 5A shows another clip for connecting the floating mass transducer to an ossicle within the inner ear.
FIG. 5B shows views of another floating mass transducer that is ready to be implanted in a patient.
FIG. 5C is an end view of the apparatus of FIG. 5 B.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides innovative floating mass transducers for assisting hearing. The following description describes preferred embodiments of the invention; however, the description is for purposes of illustration and not limitation. For example, although specific steps are described for making a floating mass transducer, the order that the steps are described should not be taken as an implication that the steps must be performed in any particular order.
FIG. 1 is a schematic representation of a portion of the auditory system showing a floating mass transducer positioned for receiving electrical signals from a subcutaneous coil inductively coupled to an external audio processor positioned outside a patient's head. An audio processor 100 receives ambient sounds and typically processes the sounds to suit the needs of the user before transmitting signals to an implanted receiver 102 . The audio processor typically includes a microphone, circuitry performing both signal processing and signal modulation, a battery, and a coil to transmit signals via varying magnetic fields to the receiver. An audio processor that may be utilized with the present invention is described in U.S. application Ser. No. 08/526,129, filed Sep. 7, 1995, which is hereby incorporated by reference for all purposes. Additionally, an implanted audio processor may be utilized with the invention.
Receiver 102 includes a coil that transcutaneously receives signals from the audio processor in the form of varying magnetic fields in order to generate electrical signals. The receiver typically includes a demodulator to demodulate the electrical signals which are then transmitted to a floating mass transducer 104 via leads 106 . The leads reach the middle ear through a surgically created channel in the temporal bone.
The electrical signals cause a floating mass within the housing of the floating mass transducer to vibrate. As will be described in more detail in reference to the remaining figures, the floating mass may be a magnet which vibrates in response to coils connected to the housing that receive the electrical signals and generate varying magnetic fields. The magnetic fields interact with the magnetic fields of the magnet which causes the magnet to vibrate. The inertial vibration of the magnet causes the housing of the floating mass transducer to vibrate relative to the magnet. As shown, the housing is connected to an ossicle, the incus, by a clip so the vibration of the housing (see, e.g., double-headed arrow in FIG. 1) will vibrate the incus resulting in perception of sound by the user.
The above description of the operation of a floating mass transducer with reference to FIG. 1 illustrates one embodiment of the floating mass transducer. Other techniques for implantation, attachment and utilization of floating mass transducers are described in the U.S. Patents and Applications previously incorporated by reference. The following will now focus on improved floating mass transducer design.
FIG. 2 is a cross sectional view of an embodiment of a floating mass transducer. A floating mass transducer 200 includes a cylindrical housing 202 which is sealed by two end plates 204 . In preferred embodiments, the housing is composed of titanium and the end plates are laser welded to hermetically seal the housing.
The cylindrical housing includes a pair of grooves 206 . The grooves are designed to retain wrapped wire that form coils much like bobbins retain thread. A wire 208 is wound around one groove, crosses over to the other groove and is wound around the other groove. Accordingly, coils 210 are formed in each groove. In preferred embodiments, the coils are wound around the housing in opposite directions. Additionally, each coil may include six “layers” of wire, which is preferably insulated gold wire.
Within the housing is a cylindrical magnet 212 . The diameter of the magnet is less than the inner diameter of the housing which allows the magnet to move or “float” within the housing. The magnet is biased within the housing by a pair of silicone springs 212 so that the poles of the magnet are generally surrounded by coils 210 . The silicone springs act like springs which allow the magnet to vibrate relative to the housing resulting in inertial vibration of the housing. As shown, each silicone spring is retained within an indentation in an end plate. The silicone springs may be glued or otherwise secured within the indentations.
Although the floating mass transducer shown in FIG. 2 has excellent audio characteristics, the silicone springs rely on surface friction to retain the magnet centered within the housing so that there is minimal friction with the interior surface of the housing. It has been discovered that it would be preferable to have the silicone springs positively retain the magnet centered within the housing not in contact with the interior surface of the housing. One way to achieve this is to create indentation in the ends of the magnet such that the ends of the silicone springs nearest the magnet will reside in the indentations in the magnet. It may preferable, however, to accomplish the same result without creating indentations in the magnet.
FIG. 3 is a cross-sectional view of another embodiment of a floating mass transducer. For simplicity, the reference numerals utilized in FIG. 3 refer to corresponding structures in FIG. 2 . However, as is apparent when the figures are compared, the silicone springs have been reversed as follows.
Silicone springs 214 are secured to magnet 212 by, e.g., an adhesive. End plates 204 have indentations within which an end of the silicone springs are retained. In this manner, the magnet biased within the center of the housing but not in contact with the interior surface of the housing. FIGS. 4A-4M will illustrate a process of making the floating mass transducer shown in FIG. 3 .
FIG. 4A shows views of a magnet and biasing mechanisms. The left side of the figure shows a cross-sectional view including magnet 212 and silicone springs 214 . The silicone springs are secured to the magnet by an adhesive 302 . The right side of the figure shows the magnet and biasing mechanisms along the line indicated by A.
FIG. 4B shows a cross-sectional view of a cylindrical housing with one end open. Cylindrical housing 202 is shown with one end plate 204 secured to seal up one end of the housing. In a preferred embodiment, the end plates are laser welded.
FIG. 4C shows a cross-sectional view of a magnet and biasing mechanisms within the cylindrical housing. The magnet and biasing mechanisms are placed within the cylindrical housing through the open end. FIG. 4D shows a cross-sectional view of a magnet biased within the sealed cylindrical housing. End plate 204 is secured to the open end of the housing and is preferably laser welded to seal the housing.
FIG. 4E illustrates beginning the process of wrapping a wire around a groove in the cylindrical housing. Preferably, the wire includes a low resistance, biocompatible material. The housing is placed in a lathe 322 (although not a traditional lathe, the apparatus will be called that since both rotate objects). Initially, wire 208 is wrapped around the housing within one of grooves 206 starting at a flange 353 between the two grooves. A medical grade adhesive like Loctite glue may be placed within the groove to help hold the wire in place within the groove. As indicated, the lathe is turned in a counter-clockwise direction. Although the actual direction of rotation is not critical, it is being specified here to more clearly demonstrate the process of making the floating mass transducer.
FIG. 4F illustrates the process of wrapping the wire around the groove in the cylindrical housing. As lathe 322 rotates the housing, wire 208 is wrapped around the housing in the groove in the direction of the arrow (the windings have been spaced out to more clearly illustrate this point). Once the wire reaches an end of the groove, the wire continues to be wound in the groove but toward the other end of the groove. As mentioned earlier, this is similar to how thread is wound onto a bobbin or spool. In a preferred embodiment, the wire is wound six layers deep which would place the wire at the center of the housing.
FIG. 4G shows a cross-sectional view of crossing the wire over to another groove in the cylindrical housing. When one coil has been wound within a groove, the lathe is stopped and the wire is crossed over flange 352 between the grooves before the wire is wound within the other groove.
FIG. 4H illustrates the process of wrapping the wire around the other groove in the cylindrical housing. The wire is wound around the other groove in a manner similar to the manner that was described in reference to FIGS. 4E and 4F except that the lathe now rotates the housing in the opposite direction, or clock-wise as indicated. Again the windings are shown spaced out for clarity.
Once the wire has been wound around the housing within the second groove to create a coil the same size as the first coil, both ends of the wire are near the center of the housing. Thicker leads 372 may then welded to the thinner wire as shown in the cross-section view of FIG. 4 I.
FIG. 4J shows a cross-section view of the thicker leads wrapped around the cylindrical housing. The thicker leads are shown wrapped around the housing one time which may alleviate stress on the weld between the leads and the wire.
FIG. 4K shows a clip for connecting the floating mass transducer to an ossicle within the inner ear. A clip 402 has an end 404 for attachment to the housing of the floating mass transducer and an end 406 that is curved in the form of a “C” so that it may be easily clamped on an ossicle like the incus. At end 406 , the clip has two pairs of opposing prongs that, when bent, allow for attachment to an ossicle. Although two pairs of prongs are shown, more may be utilized.
FIG. 4L shows the clip secured to the floating mass transducer. End 404 is wrapped and welded around one end of housing 202 of the floating mass transducer as shown. End 406 of the clip is then available for being clamped on an ossicle. As shown, the clip may be clamped onto the incus near where the incus contacts the stapes.
FIG. 4M shows views of a floating mass transducer that is ready to be implanted in a patient. The left side of the figure shows a cross-sectional view of the floating mass transducer. The housing includes a coating 502 which is made of a biocompatible material such as acrylic epoxy, biocompatible hard epoxy, and the like. Leads 372 are threaded through a sheath 504 which is secured to the housing with an adhesive 506 . The right side of the figure shows the floating mass transducer along the line indicated by A.
FIG. 5A shows another clip for connecting the floating mass transducer to an ossicle within the inner ear. A clip 602 has an end 604 that for attachment to the housing of the floating mass transducer and an end 606 that is curved in the form of a “C” so that it may be easily clamped on an ossicle like the incus. At end 606 , the clip has rectangular prongs with openings therethrough.
FIG. 5B shows views of another floating mass transducer that is ready to be implanted in a patient. The left side of the figure shows a cross-sectional view of the floating mass transducer. As in FIG. 4M, the housing includes coating 502 and leads 372 are threaded through sheath 504 which is secured to the housing with adhesive 506 . Clip 602 is not shown as the cross-section does not intercept the clip. However, the position of the clip is seen on the right side of the figure which shows the floating mass transducer along the line indicated by A.
Clip 602 extends away from the floating mass transducer perpendicular to leads 372 . Additionally, the clip is twisted 90° to improve the ability to clip the floating mass transducer to an ossicle.
While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications and equivalents may be used. It should be evident that the present invention is equally applicable by making appropriate modifications to the embodiments described above. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the metes and bounds of the appended claims along with their full scope of equivalents. | A dual coil floating mass transducer for assisting a person's hearing is provided. Inertial vibration of the housing of the floating mass transducer produces vibrations in the inner ear. A magnet is disposed within the housing biased by silicone springs so that friction is reduced between the magnet and the interior surface of the housing. Two coils reside within grooves in the exterior of the housing which cause the magnet to vibrate when an electrical signal is applied to the coils. | 7 |
BACKGROUND OF THE INVENTION
This invention is concerned with the improvement of a pneumatically driven nut running tool, such as an impact wrench, with directional torque selector mechanism which enables the operator to effect a change in the torque output value of the tool as needed according to the work involved and the intended torquing direction.
A tool of this improved nature is especially desirable for wheel work in auto service stations in applying or removing fasteners such as lug bolts, as well as in other applications.
The full torgue capacity of the tool is often required in a reverse direction to remove overtightened or frozen lug bolts; whereas a lesser torque is desired to be applied at times in a forward direction to avoid overtightness and possible damage to components of the vehicle such as the rotor in disc brake applications when installing the bolts.
A general object of the invention is to provide a pneumatically driven nut running tool, such as an impact wrench, with directional torque and torque value control means which will enable the operator to select not only the direction of torque output but also to regulate the value of the output.
A further object is to provide in a rotary impact wrench a directional flow control valve of the back-and-forth push type for controlling the direction of air flow to the motor of the tool and having integral regulatory means for controlling the volume of air flow to the motor.
In accordance with the invention there is provided a pneumatically powered nut running tool comprising a reversible rotary air motor, a throttle valve for admitting supply air to the tool, a manually slidably positionable control valve located between the throttle valve and the motor for controlling directional application and volume of supply air flow to the motor, the control valve being slidable to a first position in which it directs supply air at full volume flow from the throttle valve to a forward driving side of the motor and being slidable to an opposite second position in which it directs supply air at full volume flow from the throttle valve to a reverse driving side of the motor, manipulative means carried by the control valve selectively operable for adjustably shortening the length of the control valve, and the control valve in its adjusted condition being slidable to a third position in which it directs supply air at a reduced volume flow from the throttle valve to the forward driving side of the motor, means for preventing sliding of the control valve beyond its first and second positions, and other means for preventing sliding of the control valve in its adjusted condition beyond its third position.
BRIEF DESCRIPTION OF DRAWING
In the accompanying drawing:
FIG. 1 is a side elevational view of a pneumatic impact wrench in which the invention is incorporated, portions of the tool being cut away for added illustration;
FIG. 2 is a section taken on line 2--2 of FIG. 1 showing the combined air flow direction and air volume control valve in its forward position allowing full volume flow to the forward driving side of the motor;
FIG. 3 is a section on line 3--3 of FIG. 2;
FIG. 4 is a view similar to that of FIG. 2 but showing the control valve in a selected adjusted position allowing a restricted volume air flow to the forward driving side of the motor.
FIG. 5 is view corresponding to that of FIG. 2, but showing a modified form of the control valve in its forward position;
FIG. 6 is a section on line 6--6 of FIG. 5; and
FIG. 7 is a view showing the control valve of FIG. 5 in its reverse position.
DESCRIPTION OF PREFERRED EMBODIMENT
Attention is directed to the several Figures of the drawing, and now especially to FIGS. 1-4 wherein the invention is illustrated as embodied in a pneumatically powered impact wrench. The tool has a general housing 10 provided with a depending pistol grip handle 11. Supported in the housing adjacent the inner face of a cap or cover section 13 of the housing is a motor assembly 14 of a conventional reversible rotary air driven vane type.
The motor assembly includes the usual reversible rotor 15 which is rotatable in conventional manner in a chamber 16 in either a forward or reverse direction accordingly as live supply air is fed to either of the usual forward and reverse directional areas of the motor chamber. The motor chamber is defined by an open ended liner 17, the ends of which are closed by the usual pair of end plates 18 and 19. The rotor has the usual axially projecting shaft ends 21, 22 supported in bearings fitted in the end plates. The forward shaft end 21 is drivingly coupled by the usual train of gearing, not shown, to a spindle 23 upon which a lug bolt engaging socket 24, broken line, is carried, whereby a lug bolt when engaged by the socket may be set or loosened.
A throttle valve 25 located in the handle of the tool is actuable by the operator to cause admission of live air from an external supply into an inlet passage 26 of the tool. A control valve 27 located in the handle between the throttle valve and the motor controls the application of the admitted air from the inlet passage to a selected directional side of the motor, and controls the exhaust of spent air from the opposite side of the motor to an exhaust passage 28 in the handle.
The control valve is of spool form; it is supported in the upper portion of the handle. It is manually slidable back and forth in a bushing 29 relative to various ports for communicating the inlet passage 26 and the exhaust passage 28 with opposite sides of the motor. It is slidable in a forward direction by manually depressing inwardly a rearwardly projecting knob 31 carried by the valve; and it is slidable in a reverse direction by manually depressing a forwardly projected end 32 of the valve.
The control valve has a full forward position, as in FIGS. 1 and 2, in which an inlet port 33 in the valve bushing connected with the inlet passage 26 communicates around a neck or first groove 34 of the valve with an outlet forward port 35 leading through a passage 36 in the housing to the forward side of the motor. In this full forward position of the valve a passage 37 from the reverse side of the motor leads through a reverse port 38 into the bushing and connects around a second groove 39 of the valve with an exhaust port 41 from the bushing opening into the exhaust passage 28 extending through the handle. In the full forward position of the control valve there is a full volume air flow to the forward driving side of the motor causing application of a maximum torque to the work.
The control valve has a full reverse position, as indicated by the broken line in FIGS. 1, 2, in which the inlet port 33 connects around the groove 34 of the valve with the reverse port 38 leading through passage 37 to the reverse side of the motor. In this reverse position the forward side of the motor connects through passage 36, a bushing port 42 and around the second groove 39 with the exhaust port 41.
A spring loaded detent 43, slidably projecting from the housing wall through the bushing into a longitudinally extending recess 44 in the body of the valve, is cooperable with one or the other of a pair of radial pockets 45 and 46 at opposite ends of the recess to determine and releasably restrain the control valve in its full forward or reverse positions. The detent has a rounded pilot end which engages in the rear or deeper pocket 46 to arrest the control valve in its full forward position, as appears in FIG. 2; and which engages in the other pocket 45 to arrest the valve in its reverse position. An inclined bottom wall of the recess connecting the pockets rides over the detent against the bias of the detent spring as the valve is moved from one position to the other. The detent also cooperates with the side walls of the recess to restrain the control valve from rotating relative to its bushing 29.
Adjustable means, as will now be described, is provided to reduce or adjust the effective length of the control valve so as to enable it to obtain a limited or less than its full forward position, in which limited position a restricted volume air flow will be applied to the forward side of the motor and, as a consequence, a lesser or limited torque will be applied to the work. This limited or less than full torque application is desired in various situations, such as when it is desired to apply a limited or less than full torque in tightening the lug bolts in automotive disc brake applications.
This adjustable means includes the knob 31 and its cooperative association with the control valve 27. The knob has a shank portion 47 slidably extending into the rear of the valve bushing 29 and having an internal threaded recess 48 engaging a threaded axially extending stem 49 of the control valve. The knob is threadedly adjustable along the stem of the valve to obtain an increase or decrease in the effective length of the valve so as to vary the moved relation of the valve to the various ports in the bushing. The detent 43 in cooperation with the detent recess 44 restrains the valve against rotation relative to the bushing so as to enable the knob to be threaded along the valve stem. A laterally extending retainer pin 51 in the shank of the knob is cooperable with an annular shoulder 54 on the valve stem to prevent an outward adjustment of the knob free of the valve.
It is to be noted that in the full forward position of the control valve (FIGS. 1, 2) the knob 31 is seated in an external cavity 52 in the back wall or cap 13 of the tool, so that there is an inadequate or inconvenient space for easy finger manipulation of the knob to make an adjustment of the valve. Accordingly, when it is desired to make an adjustment of the control valve to cause application of a limited torque to the work, the valve is first moved to its reverse position where the knob is displaced sufficiently away from the back wall of the tool to allow convenient manual turning of the knob, as appears by the broken line in FIG. 1.
While the control valve is in its reverse position, the adjustment is made by turning the knob clockwise (FIGS. 1, 2) a prescribed distance. The knob is then thumb-pressed forwardly until it seats in the cavity 52 against the back wall of the housing of the tool. The effective length of the control valve, that is the portion extending forwardly beyond the shank of the knob, will have been reduced by the adjustment. The adjusted control valve now will, when depressed forwardly, obtain the limited forward position shown in FIG. 4. In the limited forward position of the control valve the body of the valve will partially cover over the forward outlet port 35 leading to the forward side of the motor. Accordingly, the volume air flow from the inlet port 33 around the groove 34 will be restricted in passing through port 35, thus resulting in a limited torque being applied to the work in a forward direction. The adjustment made to the control valve will not affect the full volume flow to the reverse driving side of the motor when the valve is moved to its reverse position.
While the control valve is in its limited forward position, vibration developing during operation of the tool might tend to cause the knob 31 to rotate relative to the valve stem out of its adjusted position. However, an O-ring 53 seated in the bushing in surrounding friction contact with the periphery of the shank portion of the knob serves to counteract this tendency.
SECOND EMBODIMENT (FIGS. 5-7)
A modification of the control valve unit is shown in FIGS. 5-7. In this form a retaining pin 61 having a fixed position in a control valve bushing 62 extends across a flat 63 on the surface of the control valve 64. The pin determines the full forward position of the valve when a rear shoulder of the flat abuts against the pin, as in FIG. 5. A return spring 66 exerting a forward bias upon the valve serves to hold the valve in its full forward FIG. 5 position.
Pin 61 also determines the full reverse position of the control valve, as in FIG. 7, when the valve is moved rearwardly until a forward shoulder of the flat abuts the pin. A spring loaded ball detent 67 projecting upwardly through the flat is adapted, as appears in FIG. 7, to obtain a position to the rear of the pin as the valve is moved to its full reverse position and, in doing so, the detent yieldably serves to restrain the valve from being returned to its forward position by the return spring 66.
Further, in this modified form the means for making an adjustment of the control valve to obtain a limited forward position of the latter for effecting application of a limited forward torque to the work, includes a sleeve knob 68 associated with a separable adjustable nut 69 threaded upon the stem 71 of the valve. A retainer ring 72 curbs the nut against being adjusted free of the valve stem.
The nut is axially slidable in the sleeve portion of the knob 68; and the sleeve portion in turn is disposed in the valve bushing 62 for relative rotation and axial sliding movement. The return spring 66 limits between an inner end of the sleeve portion of the knob and an opposed end of the valve, whereby the valve and knob are constantly biased in opposite directions.
A group of balls 73 function in a forward position of the control valve, as in FIG. 5, to latch the knob against relative rotation and axial movement. In a reverse position, FIG. 7, of the valve the balls provide a driving spline connection between the knob and the nut 69 to enable the making of an adjustment of the control valve for obtaining a limited forward position of the latter and consequent application of limited forward torque to the work.
The balls 73, here three in number, are spaced equally apart circumferentially; and each is located in a separate hole in the sleeve portion of the knob. In the full forward position of the control valve (FIGS. 5, 6) the outwardly protruding portions of the balls are seated in a pocket defined by an annular groove 74 in the surrounding bushing 62; and inwardly protruding portions of the balls are seated against individual inside radiused shoulders 75 of the nut. The forward bias of spring 66 on the valve serves to pressure the shoulders of the nut against the balls so as to hold the latter engaged in pocket 74.
Extending forwardly from each radiused shoulder 75 of the nut is a longitudinal spline groove 76. It can be seen that, when the control valve is thumb-pressed rearwardly from the FIG. 5 position to its FIG. 7 reverse position, the radiused shoulders 75 of the nut will be carried away from the balls as the nut is carried by the valve rearwardly into the sleeve portion of the knob. In this action the rearward force of the spring 66 acting through the sleeve portion upon the balls will cause the balls to be released from the pocket 74 into the spline grooves 76 of the rearwardly moving nut. Release of the balls causes the knob to be moved rearwardly by the spring relative to the housing until slightly outwardly protruding portions of the balls abut against a stop ring 77. And, when the valve has been fully advanced to its reverse position, it will be yieldably latched in such position by the cooperation of the detent 67 with the rear side of the retainer pin 61.
The release of the balls into the spline grooves 76 provides a rotary driving spline connection between the knob and the nut; and the rearwardly moved condition of the knob facilitates manual gripping thereof to effect an adjustment of the control valve. In making the adjustment, rotation of the knob for a prescribed distance in a clockwise direction acts through the balls in its sleeve portion and the spline grooves to cause travel of the nut along the valve stem 71 and a consequent drawing or adjustment of the valve into the sleeve of the knob. In this driving of the nut the valve is restrained from rotating with the nut by means of the flat 63 and retaining pin 61.
As a result of the adjustment made of the nut the effective length of the control valve is correspondingly reduced. This adjustment will not affect the volume of air flow to the reverse side of the motor since the full reversed condition of the valve is not changed. However, when the control valve is depressed forwardly, the adjusted valve will restrict flow of inlet air to the forward side of the motor. When the knob 68 is depressed in this action to position the valve in its limited forward position the balls 73 re-engage in the pocket 74 and the spring 66 acting through the valve returns the nut to re-position its shoulders 75 against the balls. | A nut running air tool improved with a back and forth manually slidable control valve located between a throttle valve and an air motor, the control valve having a forward position allowing full volume air flow to the motor and maximum forward torque output, a reverse position allowing full volume air flow to the motor and maximum reverse torque output, and the control valve having integral manipulative means for adjusting its effective length so as to permit it to be moved to a third position allowing a restricted volume air flow to the motor and restricted forward torque output. | 5 |
This application is a divisional application of U.S. Ser. No. 07/497,175, filed Mar. 21, 1990, now U.S. Pat. No. 5,272,131.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a process for forming thick film superconducting coatings on a polycrystalline substrate and, more particularly, to a process for forming a thick film of Bi a Sr b Ca c Cu d O x (BSCCO) on a polycrystalline substrate.
2. Description of the Prior Art
It has been determined that the critical temperature of BiSrCaCu x Og compound is largely determined by the sintering conditions (annealing temperatures and cooling rate), as well as the Cu content. For example, it was experimentally observed that for X=1.5 no sign of superconductivity was observed above 10K. Locquet et al., Solid State Communications, Vol. 66, No. 4, pp. 393-395 (1988). These same tests were conducted by sintering pellets of the preparative compounds, heated to temperatures up to 880° C., followed by slow cooling in air to room temperature to yield randomly oriented polycrystalline bodies having 0 resistance at 72K.
It is known that superconductivity can be obtained with Bi-Sr-Ca--Cu--O systems by first calcining in air the mixture of starting oxides and carbonates at temperatures between 800°-900° C. and then annealing at temperatures up to 870° C. It was found that with higher annealing temperatures, the metallic character of the resistivity is often lost, and superconductivity is deleteriously affected. S. A. Shaheen, Solid State Communication, Vol. 66, No. 9, pp. 947-951 (1988).
The superconducting transport properties of high temperature superconducting are highly anisotropic, and the critical currents in oriented films are much higher than those in unaligned materials. It is not known whether highly oriented thick films of BSCCO exhibiting superconductivity at elevated temperatures can be formed on a polycrystalline substrate.
It was believed that a superconductor coating should be applied to single crystal substrates for the purpose of matching the lattice structure of the coating with that of the substrate in order to obtain an aligned coating, i.e., a coating with a high current carrying capacity. Conversely, it was believed that the use of a polycrystalline substrate would inhibit the alignment of a superconductor coating thereon; consequently, the use of polycrystalline substrates was considered to be undesirable. For example, a thick BSSCO coating has been applied to a monocrystalline MgO substrate, but no attempt was made to apply it to a polycrystalline MgO substrate. Y. Akamatsu et al. , Jpn. J. Appp. Phys. Letters, 27 L1696-L1698 (1988) . In the process described by Akamatsu, a powdered mixture of Bi 2 O 3 , CaCO 3 , SrCO 3 , and CuO are ground together and melted at 1200° C. for 30 minutes without calcination or sintering on an MgO single crystal substrate in air. The melt is then cooled in a furnace at about 40° C./minute to a selected temperature between 700°-900° C. for periods of time from 0 to 2 hours, and then air cooled to room temperature. This procedure often results in the formation of undesired impurities, i.e., CaCuO x or (CaSr)CuO x or secondary phases.
It is desirable to have a process for forming thick film superconducting coatings of BSCCO on polycrystalline substrates. This is especially true because coatings made via melt/crystallization techniques are useful in the preparation of devices with complex shapes such as magnetic shields and microchip transmission lines. It is also desirable to provide a process of forming such a superconducting coating without significant amounts of undesirable impurities.
SUMMARY OF THE INVENTION
A process is provided for forming an oriented thick film superconducting coating on a polycrystalline substrate, the coating comprising at least two highly oriented components of
Bi.sub.a Sr.sub.b Ca.sub.c Cu.sub.d O.sub.x (BSCCO)
wherein, in one component, a is 2, b is 2, c is 1, d is 2, and x is 8 and, in another component, a is 2, b is 2, c is 0, d is 1, and x is ≈6, said process comprising applying a powdered mixture prepared from Bi 2 O 3 , SrCO 3 , CaCO 3 , and CuO onto a polycrystalline substrate; rapidly heating the resultant coated substrate to a temperature of from about 1000°-1100° C. for a period of from about 5-30 minutes, thereby melting the powder and forming a thick film coating; rapidly quenching the coated substrate to below 500° C., which is below the temperature at which phase transition occurs; and annealing the resultant coated substrate by heating in an atmosphere of an oxygen-containing gas to a temperature of from about 850°-870° C. Suitable polycrystalline substrates are MgO and alumina and mullite. Optionally, the resultant annealed coated substrate can be lightly polished to remove at least some of the resultant excess CaCuO 3 on the surface of the thick film coating. Additionally and optionally, the polished coated substrate can be annealed by heating to a temperature of from about 840°-870° C.
DETAILED DESCRIPTION OF THE INVENTION
It has been unexpectedly found that a highly oriented thick film of superconducting material can be formed by using melt/crystallization techniques on polycrystalline substrates. Coated polycrystalline substrates coated according to the present invention have been unexpectedly found to have a resistance of 0 at a temperature of 80 K. or higher and a current density J c greater than 1700 A/cm 2 at 64 K. and greater than 6000 A/cm 2 at 4.2 K.
According to the present invention, a powder mixture for use in coating the substrate is prepared by mixing BiO 3 , SrCO 3 , CaCO 3 , and CuO. In a preferred embodiment, the stoichiometric ratios of these components can be 4:3:3:4, 4:3:3:6, 2:2:2:3, and 2:2:3:4, respectively. However, other stoichiometric ratios of these components can be used.
Preferably, these components in powdered form are mixed and milled in a solvent, the solvent evaporated, and the resultant mixture calcined in air. In a preferred embodiment, the powdered mixture is calcined at a temperature of from about 840°-860° C. to remove carbonate and any hydroxides and water. More preferably, calcining is carried out by rapidly heating the powder to about 857° C. for about 3 hours in air or in a vacuum and then cooling slowly over a period of about 16 hours in oxygen to 250° C. after a holding period of 4 hours between 875°-825° C. Although there is no limitation on the weight of the resultant calcined powder to be used per unit area of the substrate, it is preferred to use a sufficient amount of the powdered coating material to cover the surface so that upon melting, a continuous coating is obtained. In a preferred embodiment, sufficient powdered coating is used to produce a coating having a resultant thickness ranging from about 75-250 μm.
Although any type of polycrystalline substrate can be used, it is preferred to use as the polycrystalline substrate MgO, alumina, or mullite. Other preferred polycrystalline substrates are SrTiO 3 , ZrO 2 , ZrTiO 4 , BaTiO 3 , Y 2 O 3 , or mixtures thereof.
Following application of the powdered coating, the resultant coated substrate is then rapidly heated to a temperature ranging from about 1000°-1100° C. for a period of from about 5-30 minutes to melt the powder and form a thick continuous coating.
In a preferred embodiment, the powder mixture applied to the substrate is no larger than about 150 μm. More preferably, the powder mixture has a size range of from about 1-10 μm.
In a preferred embodiment, after the powder mixture has been applied to the polycrystalline substrate, it is heated to a temperature of from about 1050°-1100° C. for a period of up to 20 minutes to effect complete melting of the coating.
The molten coating is then preferably rapidly quenched to a temperature below which phase transition occurs. In a preferred embodiment of the present invention, the rapid quenching is conducted in an oxygen-containing gas at a temperature decrease of at least 50° C. per minute, more preferably, from about 100° C. per minute to about 125° C. per minute to below 500° C. and preferably to room temperature. In the quenching step, the oxygen-containing gas can be air, pure oxygen, or, preferably, a gas containing 10-15 vol. % of oxygen. In another embodiment, the melting and rapid quenching can be effected in a vacuum.
After quenching to room temperature, the coated substrate can then be annealed by heating in an atmosphere of an oxygen-containing gas to a temperature of from about 850°-870° C., more preferably from about 855°-860° C. for a period of preferably from 1-2 hours. Other heating periods can be used, depending on the annealing temperature. In a preferred embodiment, the surface layer of the film is heated treated in flowing O 2 by heating it rapidly over a period of ≈5 hours from room temperature to 860° C., cooling to 825° C. in 4 hours, and then cooling to 700° C. in 10-30 hours. The heated sample is preferably held at 700° C. for 10 hours and then cooled to room temperature in 4-50 hours.
Optionally, the resultant annealed coated substrate is lightly polished with dry No. 600 grit SiC paper, cleaned ultrasonically in dry alcohol or acetone, and dried to remove most of any CaCuO 3 impurities formed on the surface of the thick film coating. The polished coated substrate can then optionally be reannealed to a temperature of from about 840°-870° C. for a period of from about 1-10 hours, more preferably 1-2 hours. The reannealing was found to contribute to the formation of additional 2212 BSCCO phase in the coating. It is believed that insignificant amounts of impurities are present in the final product produced according to the present invention.
When sufficient powder is applied to the polycrystalline surface, the thickness of the resultant melted thick film coating ranges from about 75-250 μm. Advantageous results can also be obtained by using in the powdered mixture Bi 2 Sr 2 Ca 2 Cu 3 O 10 .
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features, and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings in which like reference characters designate the same or similar parts throughout the several views and wherein:
FIGS. 1(a) and 1(b) shows several X-ray diffraction patterns of a thick 2201 BSCCO film on a polycrystalline MgO substrate produced by the process of the present invention. The relative intensity scale in FIGS. 1(a) and 1(b), is logarithmic. FIGS. 1(a) shows the x-ray diffraction pattern of the film after one anneal with Ca 2 CuO 3 present. The indices of the 2212 peaks are above them; x indicates Ca 2 CuO 3 or (Ca,Sr) 2 CuO 3 . FIG. 1(b) shows the same x-ray diffraction pattern of the film after polishing and reannealing. The alignment of both the high (2212) and low (2201) T c material is also shown.
FIG. 2 is a photomicrograph of the surface of a coating produced according to the present invention showing a typical area of a well-aligned film after mechanical removal of the Ca 2 CuO 3 needles and reannealing (the bar represents 77 μm).
FIGS. 3(a) and 3(b) show several optical micrographs of a 4336 composition film on polycrystalline MgO. FIG. 1(a) shows the film as initially annealed with BSCCO platelets (the bar represents 77 μm). FIG. 1(b) shows the Ca 2 CuO 3 needles near the film surface (the bar represents 77 μm).
FIG. 4 is a graph of resistivity versus temperature for a well-aligned BSCCO film produced according to the present invention. The graph illustrates that the resistivity values are relatively low as compared to typical unoriented films.
FIG. 5 is a plot of typical data collected for a J c measurement on a surface ground and reannealed film produced according to the present invention. Sample dimensions for the film are t=0.1 mm, w=1.3 mm, and l=13.4 mm, where t is thickness, w is width, and l is length.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever.
In the foregoing and in the following examples, all temperatures are set forth in Kelvin or degrees Celsius; and, unless otherwise indicated, all parts and percentages are by atomic percent.
The entire disclosures of all applications, patents and publications, cited above and below, are hereby incorporated by reference.
EXAMPLE 1
Preparation of Coated Samples
Thick films of BSCCO were prepared from stoichiometric ratios (4334, 4336, 2223, and 2234) of high purity Bi 2 O 3 , SrCO 3 , CaCO 3 , and CuO. The powders were mixed and milled in acetone with ZrO 2 balls for 24 hours and then flash dried. They were then calcined in air at ≈850° C. for 1-4 hours to form a BSCCO precursor. The calcined BSCCO precursor was ball-milled with ZrO 2 balls for ≈1 hour in acetone and dried. The milled powder was then placed as a thin layer on top of the substrate. Polycrystalline MgO (Norton Company, Worcester, Mass.); cut from randomly oriented, hot-pressed discs with grain size of about 50 μm), single crystal MgO (001), and polycrystalline Al 2 O 3 were used as substrates. The "coated" substrates were heated to ≈1050° C. After a brief hold (≦20 minutes) to ensure complete melting, the samples were typically quenched at a rate of temperature drop of at least 100° C./min to room temperature in air. The coated substrates were then annealed in air or O 2 for at least 15 hours at 860° C. and then furnace cooled to room temperature at a controlled rate in flowing O 2 . Several samples were subjected to a second anneal. In one variation, a melted, quenched, and annealed sample was lightly polished and then reannealed at 860° C. and slowly cooled. In a second variation, a melted, quenched, and annealed sample was heated to 850° C. and then quenched again and sectioned. In a third variation, after melting, several samples were allowed to cool very slowly to the annealing temperature instead of quenching to room temperature, followed by reheating to 860° C. and then annealing.
EXAMPLE 2
Testing of Control Samples
Samples were examined visually and then with: X-ray diffraction; optical microscopy; scanning electron microscopy with energy dispersive analysis (SEM with EDS); resistance versus temperature measurements; and critical current measurements. The resistance measurements were made using a four-point probe technique with gallium-indium electrodes. Critical current measurements were made using a four-point probe technique. The sample film was ground into the shape of a letter H. The vertical parts of the letter served as the current electrodes and the voltage was measured at two points along the horizontal bar 3.4 mm apart. The bar was 1.3 mmwide and 0.1 mm thick. The sample was immersed in liquid He (4.2 K.) or pumped liquid nitrogen (74 and 64 K.) for the test. The E-Field criterion was used for the determination of J c and 10 μV/cm. No external magnetic field was applied.
Visual observation revealed that on a macrographic scale, the process of the present inventions yielded dense, uniform, reflective coatings, about 150 μm thick, on both polycrystalline and single crystal MgO. The edges and back of the MgO substrates were partially coated with BSCCO, indicating that BSCCO wets MgO. In the case of Al 2 O 3 , the wetting was not as complete and the coating was highly non-uniform.
X-ray diffraction analysis of the fired thick films on MgO substrates showed that all of the films were crystalline and highly oriented with either Bi 2 Sr 2 CaCu 2 O x (2212) or Bi 2 Sr 2 Cu 1 O x (2201) as the predominant phase. Heat treatment affected the relative proportions of 2201 and 2212, but unlike melted and quenched bulk materials, many thin film materials, plasma-sprayed thick films, and sintered bulk or thick film samples, amorphous or randomly oriented films were not produced. Even the as-quenched films were crystalline and highly oriented. The 2212 BSCCO was analyzed on the basis of a pseudotetragonal unit cell yielding unit cell parameters of approximately a=0,382 nm and c=3.05 nm. The 2201 BSCCO was also analyzed as a pseudotetragonal material with unit cell parameters of approximately a=0,383 nm and c=2.42 nm. A typical diffraction pattern is shown in FIG. 1. The orientation of the crystallites is indicated by the greatly enhanced intensities of the (001) lines and the almost complete absence of any non-(001) lines. All the precursor compositions gave similar results, although the 4336 compositions produced films with the highest amounts of 2212 phase and the largest J c s.
A combination of X-ray diffraction analysis, SEM/EDS and optical microscopy identified Ca 2 CuO 3 (or Ca,Sr) 2 CuO 3 ) as a minor phase. For the 4336 compositions, the amount of Ca 2 CuO 3 was significant; it was less so for the 4334 compositions. The optical microscopy and SEM analysis indicated that the cuprate phase existed predominantly on top of the BSCCO layers after the quenched films were annealed. This indicated that the as-annealed films were not homogenous. Gentle polishing of the surface layer of a 4336 film removed the Ca 2 CuO 3 needles. They did not reappear after a subsequent anneal at 860° C.
The presence of the cuprate needles prompted further investigation of the homogeneity of the samples. Of special interest was the relative proportions of the 2212 and 2201 phases in the interior of the films. The quenched and annealed film which was polished to remove the cuprate needles was X-rayed before it was polished, after it was polished, and after it was reannealed. Before polishing, the surface was ≈90% 2212 phase and ≈10% 2201 phase. After polishing, the sample was ≈50% 2212 and ≈50% 2201. This indicated that the relative proportions of 2212 phase and 2201 phase varied through the thickness of the films after the annealing treatment. Reannealing the sample at 860° C. restored the surface composition to ≈90% 2212 phase and ≈10% 2201 phase. Visual observation indicated that some melting occurred during the reanneal at 860° C. since the cracks from polishing marks had healed. By comparison, X-ray diffraction of the as-quenched films indicated they were ≈70% 2212 phase and ≈30% 2201 phase near the surface. This shows that the initial annealing treatment increased the relative proportion of 2212 near the surface of the films, although it did not produce homogenous films.
EXAMPLE 3
Reannealed Samples
To further understand the effects of heat treatment, another quenched and annealed 4336 film was reannealed and then sectioned and films cooled slowly from the melting temperature to the annealing range were examined. The quenched and annealed 4336 film was not polished to remove the cuprate needles before it was reannealed by heating it up to 850° C. and then quenching. This treatment did not affect the surface composition, it remained at >90% 2212 phase and<10% 2201 phase. However, it did appear to affect the homogeneity of the interior of the film. After grinding about 50 μm from the surface, the sample remained >90% 2212 phase and<10% 2201 phase, although the alignment was not quite as good as that on the outer surface. Grinding another 50 μm from the sample did not change the X-ray pattern significantly. It was still>90% 2212 phase and<10% 2201 phase with less alignment than the original surface, indicating that the second anneal had helped to homogenize the film and increase the 2212 content throughout. When the 4336 precursor composition was melted and then allowed to cool very slowly to the annealing temperature, rather than being quenched to room temperature before annealing at 860° C., very little of the 2212 BSCCO phase was observed. Instead, the predominant phase was the Ca-free 2201 phase (as indicated by the X-ray peaks at 20=7.5° and 21.9° ). (Ca,Sr)-Cu-O oxides were also present. Annealing did not significantly reduce the amount of the 2201 phase, nor did it increase the amount of the 2212 phase.
The results of these tests show that the phase equilibria may be complex and that physical separation of the Ca-rich and Ca-poor phases occurs during slow cooling from the melt. Quenching minimizes the phase separation in the film and keeps the excess Ca and Cu distributed relatively uniformly within the film. When a quenched sample is annealed, the 2212 phase can then be formed by the reaction of the 2201 phase with calcium and oxygen. As previously noted, the as-quenched films were>70% 2212 and<30% 2201 by X-ray analysis of the surface, while the quenched and annealed samples were >90% 2212 and <10% 2201 by X-ray analysis of the surface. The reaction of 2201 to form 2212 is apparently controlled by the distance between the 2201 phase and the excess Ca and Cu rather than diffusion of oxygen in from the surface of the film. A second anneal at 850° C. produced a sample that was >90% 2212 throughout its thickness, and, while the amount of 2212 in the slow-cooled sample was not increased by annealing, it was increased by remelting and quenching. Had oxygen diffusion been the rate-controlling step, the reanneal of the slowly cooked samples would have increased the amount of 2212.
The homogeneity of the sample (including its oxygen content) was found to be important. The film which had been polished to remove the cuprate needles and then reannealed had a higher R=0 temperature (80 K.) and a larger J c (>1700 A/cm 2 at 64 K. and >6000 A/cm 2 at 4.2 K.) than the films which were only annealed once (R=0 at 72-75 K. and J c =50-100 A/cm 2 at 64 K.). These results, in conjunction with the sectioning results of the sample reannealed at 850° C., indicate that reannealing increases the homogeneity of the film and thus effectively increases the cross-sectional area of the 2212 phase available to carry current. These tests show that according to the present invention, a thick film on polycrystalline MgO which is highly oriented and at least 90% 2212 will be superconducting at temperatures below 80 K. with the ability to carry currents >103 A/cm 2 at 64 K.
FIGS. 3a and 3b show the optical micrographs of the BSCCO and Ca 2 CuO 3 regions. The large grain size and preferred orientation of the BSCCO platelets are evident. The Ca 2 CuO 3 phase formed as needles or as fan-shaped clusters of needles. These were oriented parallel to the surface of the substrates. FIGS. 2 and 3 also show that the grain size of the 2212 BSCCO is ≈200 μm, which is significantly greater than the grain size of the randomly oriented polycrystalline substrate. These tests show that the orientation is a result of the crystallization and that crystallization occurs from the surface, since the surface is more highly oriented than the interior. Consequently, finer grained polycrystalline MgO substrates can be used to support oriented BSCCO films because the compatibility of the MgO substrates is related more to the wetting of the substrate by BSCCO than to crystal structure considerations. The melting of the BSCCO is also important, since it allows orientation of the crystallites during the crystallization process, resulting in much denser films than would be possible if randomly oriented crystallites had formed during standard solid state sintering.
The fired 2212 coatings were superconducting. FIG. 4 shows a typical resistance-temperature curve with R=0 at 75 K. In general, the T c was near 80 K. for the 2212 material, with more homogenous films having higher T=0 temperatures. The critical current of the fired films was also a function of microstructure, as already discussed. Samples which had not been homogenized by reannealing had relatively low critical currents (J c ≈100 A/cm 2 ) at 64 K. and lower R=0 temperatures (72-75 K.). The sample which was polished to remove the cuprate needles and then reannealed had much higher critical current densities, J c >1700 A/cm 2 at 64 K. and J c >6000 A/cm 2 at 4.2 K. (see FIG. 5) and a higher R=0 temperature (80 K.).
The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. | An article comprises an oriented thick film superconducting coating on a polycrystalline substrate. The coating includes at least two highly oriented platelet components of
Bi.sub.a Sr.sub.b Ca.sub.c Cu.sub.d O.sub.x (BSCCO)
wherein, in one component, a is 2, b is 2, c is 1, d is 2, and x is 8 and, in another component, a is 2, b is 2, c is 0, d is 1, and x is ≈6, oriented such that said BSCCO platelets are essentially parallel to said substrate. Suitable polycrystalline substrates are MgO and alumina and mullite. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Dutch Patent Application No. NL 1028037, filed Jan. 14, 2005, the contents of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a device for treating pieces of a substrate with a supercritical or near-critical treatment medium, which may for example comprise CO 2 , N 2 O, lower alkanes, such as ethane and propane, or mixtures thereof, at high pressure in a pressure chamber, piece by piece or in batches, with a mechanical action being carried out in the treatment medium.
BACKGROUND OF THE INVENTION
The prior art has disclosed a number of variants of a device of this type, in which an electric motor is used as drive for carrying out the mechanical action. However, the said treatment media have the drawback of dissolving many polymers therein. This can give rise to problems with regard to sticking, softening and expansion or even bursting of the polymer if it comes into contact with the treatment medium. This problem becomes more serious the higher the density of the treatment medium, such as for example in liquid or supercritical phases of the treatment medium under ever higher pressures. This may give rise to considerable problems in the event of an electric motor coming into contact with treatment media of this type, for example short-circuiting as a result of the electrical insulation of the motor windings being affected, leaks caused by damage to any sealing rings, and jamming caused by fretting of plastic bearing components. Furthermore, treatment media of this nature are able to dissolve may oils and greases. This leads to removal of grease from anything which comes into contact with the treatment medium. This problem is likewise exacerbated as the density of the treatment medium rises. In the case of the electric motor, this can give rise to problems with lubricated surfaces in the bearing of the motor shaft, as well as with any bearings used in the mechanical actuator.
To avoid the above complications, the electric motor can be positioned outside the sphere of influence of the treatment medium, i.e. outside the pressure chamber. The mechanical actuator provided inside the pressure chamber is then driven by a drive shaft which passes through a wall of the pressure chamber. However, this presents specific problems with the need to seal the drive shaft. Sealing problems of this nature are exacerbated at higher pressures of the treatment medium, resulting in an expensive structure.
An alternative is to make use of a magnetic coupling between the electric motor and the mechanical actuator, as shown for example in U.S. Pat. No. 5,267,455. There is no need for seals in this case. However, at high pressures, the wall thickness of the pressure chamber increases and consequently the magnetic coupling is more difficult to realize, certainly if high powers need to be transmitted. This leads to very expensive structures.
WO 00/63483 also discloses a device showing a washing machine drum which is driven by an electric motor. In this case, the washing machine drum and the electric motor are both located in a treatment space which is partially filled with highly pressurized liquid CO 2 at room temperature. The document describes the electric motor having to be disposed as high as possible within the top part of the treatment space, so that the electric motor substantially, i.e. barring a few splashes of liquid CO 2 , only comes into contact with gaseous CO 2 .
One drawback in this case is that this known device is susceptible to faults and problems may still arise as a result of standard polymer components of the electric motor being adversely affected. Furthermore, the working range of the permitted pressure and temperature are limited, and consequently in some cases so is the effectiveness of the washing treatment which is intended in this case.
SUMMARY OF THE INVENTION
It is an object of the invention to at least partially overcome the abovementioned drawbacks and/or to create a useable alternative. In particular, it is an object of the invention to create a reliable and efficient device for treating pieces of a substrate at high pressure, piece by piece or in batches, with a treatment medium in the supercritical or near-critical state.
This object is achieved by a device according to the present invention. In this case, the device comprises a first pressure chamber, which is provided with a closable feed opening for placing pieces of substrate in the pressure chamber, and a pipe system for supplying and discharging the treatment medium, which may comprise, for example, CO 2 , N 2 O, lower alkanes, such as ethane and propane, or mixtures thereof, to and from the pressure chamber under high pressure. In the first pressure chamber or in a second pressure chamber coupled to the first pressure chamber under the high pressure, there is an electric motor for driving an actuator to carry out a mechanical action in the treatment medium. The electric motor is in this case open to the treatment medium and the electric motor is disposed and designed to be accessible to the treatment medium, in such a manner that during the treatment of a substrate the supercritical or liquid treatment medium flows through and around the electric motor.
Surprisingly, it has been found that, despite the drawbacks described in the prior art, it is none the less readily possible for an electric motor to be designed in such a manner that it can be exposed from the inside and the outside to the supercritical or near-critical liquid treatment medium and is able to withstand it. In the invented device, the electric motor is located in the process tank at the high process pressure; this high pressure prevails both outside and inside the electric motor. The pressure inside the motor casing is then advantageously substantially equal to the pressure outside the electric motor, i.e. in the relevant pressure chamber. As a result, the electric motor can be of simpler and less expensive design. Inter alia, there is no need for a seal between the motor shaft and the motor casing, and the casing does not need to have any additional structural strength in order to withstand high pressure differences. Another advantage is that the supercritical or near-critical liquid treatment medium contributes to cooling the electric motor. Put another way, the heat which is dissipated by the electric motor can advantageously be used to keep the treatment medium at process temperature during the treatment of a substrate.
The motor windings of the electric motor may be insulated using insulation material which is resistant to the specific treatment medium, and it is possible to use a lubrication-free bearing for a motor output shaft of the electric motor. These measures make it more readily possible for the device to function without problems under various operating conditions, in particular even at pressures and temperatures which are so high that the treatment medium is in the supercritical or near-supercritical phase.
The electric motor may comprise a motor casing which is provided with inlet openings for allowing the treatment medium to flow into the electric motor as far as around the motor windings. The inlet openings allow the treatment medium to flow freely through the interior of the electric motor, with the result that successful cooling of the motor windings can be achieved. For example, there is no longer any need for cooling fins on the motor casing.
Further preferred embodiments are defined in the subclaims.
The invention also relates to the use of a device for treating pieces of textile substrate at high pressure, piece by piece or in batches. Additionally, the invention relates to use of a device for treating pieces of a substrate at high pressure, piece by piece or in batches, with a treatment medium wherein the pressure and temperature at which the treatment medium is supplied to a pressure chamber during treatment are such that the treatment medium is in a supercritical or near-critical state, and in which an electric motor for driving an actuator for carrying out a mechanical action in the treatment medium is located in the treatment medium, which is in the supercritical or near-critical state, with the treatment medium flowing through and around it. Further, the invention relates to use of a device for treating pieces of a substrate at high pressure, piece by piece or in batches, with a treatment medium in particular according to one of the preceding claims, wherein the pressure and temperature at which the treatment medium is supplied to a pressure chamber during treatment are such that the treatment medium is at least partially in a liquid phase, and in which an electric motor for driving an actuator for carrying out a mechanical action in the treatment medium is submerged in the treatment medium, which is in the liquid phase, with the treatment medium flowing through and around it.
The invention also relates to an electric motor for a device which is open to the treatment medium and is designed to be accessible to the treatment medium, in such a manner that during treatment of a substrate with a treatment medium, the treatment medium can flow through and around the electric motor.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explained in more detail with reference to the appended drawing, in which:
FIG. 1 shows a diagrammatic view of an embodiment of a pressure chamber with an electric motor fixed to the housing therein, for a device according to the invention with pump;
FIG. 2 shows a cross-sectional view through an electric motor which can be used in a device as shown in one of FIGS. 1 , 4 , 5 and 6 ;
FIG. 3 shows a side view of FIG. 2 ;
FIG. 4 shows a variant of FIG. 1 with the direction of flow reversed;
FIG. 5 shows a variant of FIG. 1 with a washing machine drum; and
FIG. 6 shows a device according to the invention in which an electric motor with pump is accommodated in one pressure vessel, a beam dyeing machine interacting with it.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 , the pressure chamber device as a whole is denoted by reference numeral 1 . The device 1 comprises a pressure chamber 2 , which is in this case formed by a pressure vessel and is provided with an opening, which can be closed by a cover 3 , for mounting an electric motor 7 with pump 9 in the pressure vessel. There is also a pipe system 5 with a feed 5 a and a discharge 5 b . An electric motor 7 is disposed in the pressure chamber 2 . A pump 9 is mounted on the motor output shaft 8 of the electric motor 7 . The pump 9 , which is formed for example by a centrifugal pump with an impellor, is in this case mounted directly on the motor shaft 8 . The pump 9 is accommodated in a pump casing 10 which comprises an inlet 11 and an outlet 12 . The outlet 12 is connected to the discharge 5 b.
The pressure chamber device shown may be incorporated as a second pressure chamber in a high-pressure circuit with a first pressure chamber for treating a substrate.
The electric motor 7 , which is shown in more detail in FIGS. 2 and 3 , comprises motor windings 20 which are insulated by an insulation material that is able to withstand a treatment medium that is specifically to be used, comprising CO 2 , N 2 O, lower alkanes, such as ethane and propane, or mixtures thereof. The insulation material preferably consists of polyester. Tests have shown that this is an eminently satisfactory material. Other materials, such as kapton or Nomex, are also possible.
Furthermore, the electric motor 7 comprises bearings 21 for the motor output shaft 8 . The bearings 21 are of the lubrication-free type, i.e. no greases or oils are required for the bearings to function correctly. The bearings 21 may comprise ceramic balls or a PEEK or bronze ball cage. It is advantageous for the bearings 21 to comprise a self-lubricating contact layer, for example in a groove in the bearings. The self-lubricating contact layer is preferably formed by a carbon-nitride layer. It has been found that such a material is well able to withstand the treatment medium (in particular supercritical CO 2 ), while sufficient lubrication of the bearings 21 is also achieved.
The bearings 21 are mounted in bearing blocks 23 , which also form a type of covers for a motor casing 24 surrounding the electric motor 7 . The bearing blocks 23 are made from a corrosion-resistant material, for example stainless steel or anodized aluminium.
Through-flow openings 26 (cf. FIG. 3 ) are provided in the bearing blocks 23 of the motor casing 24 . This means that the electric motor 7 is of an open type and the treatment medium is free to circulate through the interior of the electric motor 7 . This ensures successful cooling of the motor windings 20 and has the advantage that the motor casing 24 can be of more lightweight design, since the pressure inside the motor casing 24 is substantially equal to the pressure outside it. Furthermore, there is no need for any cooling fins, on account of the thermal properties of the treatment medium, and the motor shaft does not have to be passed through the motor casing 24 in such a manner as to be sealed with respect to the treatment medium at the supercritical process pressure.
The electric motor 7 is supplied with power via an electrical connection 27 , which is provided with insulation material that is able to withstand the treatment medium, for example Nomex, aramid paper, kapton, polyester film and/or yarns. The electrical passage of the connection 27 through the wall of the pressure chamber 2 is provided with a tensile stress reliever which is able to withstand the treatment medium, for example a Buna-N ring or potting resin.
During operation, treatment medium is fed to the pressure chamber 2 via the feed 5 a , and the electric motor 7 with the pump 9 is set in operation. Some of the treatment medium flows freely through the motor casing 24 , where it has a cooling action, is sucked in by the pump 9 via the inlet 11 and is pumped by the mechanical action of the pump 9 to the outlet 12 or discharge 5 b , leaves the pressure vessel 2 and enters another (first) pressure chamber (not shown), where the pieces of substrate are located, where it carries out a treatment on the pieces of substrate. After it has left the first pressure chamber, the treatment medium is fed back to the feed 5 a , via an associated pipe. After the treatment medium which is circulating in this way has been able to act on the pieces of substrate for a desired time, the electric motor is stopped and the treatment medium is discharged from the system until the system is at ambient pressure, and then the treated pieces of substrate can be removed from the first pressure chamber again.
The pressure across the pump casing 10 in which, for example, an impellor of the pump is rotating is at most equal to the boost pressure provided by the pump 9 , and is therefore advantageously only a few bar, while the treatment medium in the pressure chamber 2 may be at a high pressure.
FIG. 4 shows a variant, in which identical components are denoted by the same reference numerals. The pressure chamber 2 is now provided with a feed 30 which is connected to an inlet 31 of the pump casing 10 . There is also a discharge 32 which is in direct, open communication with the pressure chamber 2 . Furthermore, through-flow openings 33 are now provided in the peripheral wall of the motor casing of the electric motor 7 .
During operation, the treatment medium flows via the feed 30 and the inlet 31 into the pump casing 10 and from there flows partly through the electric motor 7 and partly around it into the pressure chamber 2 and then back out via the discharge 32 .
FIG. 5 shows an application in which an electric motor 40 and a drum 41 driven by it are positioned together in the same pressure chamber 42 . Treatment medium can be fed to and discharged from the pressure chamber 42 (pipes not shown). The electric motor 40 is provided with through-flow openings 44 , while the abovementioned measures according to the invention are preferably once again taken for the motor windings and the bearings used. The pressure chamber 42 is provided with a cover 43 which can be opened in order for pieces of substrate that are to be treated to be put into and taken out of the drum 41 . The drum 41 can be used both for washing and for dyeing.
FIG. 6 shows a cylindrical pressure vessel 50 which is provided at both ends with feed openings which can be closed off by covers 51 , 51 a and 51 b . Both the pressure chamber for the electric motor with actuator and the pressure chamber for the pieces of substrate are integrated in this pressure vessel 50 . The cover 51 a can be opened in order for a rolled-up piece of textile substrate 53 to be introduced into the pressure chamber on a perforated tube 52 . The cover 51 b is provided with a feed 55 and a discharge 56 for treatment medium. A pump casing 58 , in which an electric motor 59 and a vane pump 60 are jointly accommodated, is directly connected to the feed 55 . The pump casing 58 holding the electric motor 59 and the vane pump 60 can be mounted in the pressure vessel 50 when the cover 51 b is open. The vane pump 60 is advantageously disposed upstream of the electric motor 59 , which contributes to better flow of the treatment medium past and if desired through the electric motor 59 , resulting in better cooling. From the pump casing 58 , the treatment medium can flow via an outlet 62 into the tube 52 and from there, via the holes, through the substrate 53 that is to be treated, performing its treating action on the substrate. Finally, the treatment medium can leave the pressure chamber 50 again via the discharge 56 . On account of the fact that the treatment medium has been laden with dye outside the pressure chamber 50 , it is in this way possible to dye the textile substrate. The pressure drop across the textile substrate is approximately 1 bar.
In a preferred use, the treatment medium is supplied to the pressure chamber of the above-described devices at a pressure and temperature which are such that the treatment medium is in a supercritical or near-supercritical state. The entire pressure chamber, including the “open” electric motor, is then at the pressure and under the influence of the supercritical or near-supercritical treatment medium. Surprisingly, it has been found that this does not present any problems, in particular if the motor windings are insulated with insulation material that is able to withstand the treatment medium and if the bearing is of a lubrication-free type. For CO 2 as treatment medium, the supercritical state is reached at a pressure of at least 73 bar and a temperature of at least 31 degrees.
In a variant, the treatment medium is supplied to the pressure chamber of the above-described devices at a pressure and temperature which are such that the treatment medium is at least partially in a liquid phase. The “open” electric motor is then preferably submerged in the liquid treatment medium. Surprisingly, this too has been found not to present any problems, in particular if the motor windings are insulated with insulation material that is able to withstand the treatment medium and if the bearing is of a lubrication-free type.
In addition to the embodiments shown, numerous variants are possible. For example, it is also possible for other types of actuators in addition to the pump and the drum to be used to move the substrate and the medium with respect to one another, for example a propeller, an agitator or a stirring mechanism. In addition to washing or dyeing pieces of a textile substrate, the device can advantageously also be used to treat other types of substrate or to treat a substrate in another way, for example clean or degrease it. Examples of articles which can also be suitably treated using the device and the use according to the invention include fabrics, such as woven and nonwoven fabrics formed from materials such as cotton, wool, silk, leather, rayon, polyester, acetate, glass fibre, fur, etc. These fabrics may be formed into pieces, such as clothing, work gloves, cloths, leather goods (for example handbags and briefcases), etc. The present device and the use can also be used to treat, in particular wash, clean or degrease, other items, such as semiconductors, micro-electromechanical systems, opto-electronics, fibre optics and machined or cast metal components. It is also possible to treat foodstuffs and contaminated soil using the device and the use according to the invention.
Therefore, the invention provides a user-friendly, efficient device which allows an electric motor that can be of simple and inexpensive design to be positioned within the sphere of influence of a specific, aggressive type of treatment medium under various conditions of use in a pressure chamber. | A device for treating pieces of a substrate at high pressure, piece by piece or in batches, with a treatment medium in the supercritical or near-critical state, includes a first pressure chamber, a pipe system for supplying and discharging the treatment medium, to and from the pressure chamber under high pressure and an electric motor, which is fixed to the housing in the first pressure chamber or in a second pressure chamber coupled to the first pressure chamber under the high pressure, for driving an actuator to carry out a mechanical action in the treatment medium. The electric motor is in this case open to the treatment medium and is disposed and designed to be accessible to the treatment medium, in such a manner that during the treatment of a substrate the treatment medium flows through and around the electric motor. | 3 |
RELATED APPLICATIONS
[0001] This application (Attorney Docket No. P216334) is a continuation of U.S. patent application Ser. No. 11/880,364, filed Jul. 19, 2007 which claims priority of U.S. Provisional Patent Application Ser. No. 60/832,103 filed Jul. 20, 2006.
[0002] The contents of the related application(s) listed above are incorporated herein by reference.
TECHNICAL FIELD
[0003] The present invention relates to protective devices for portable video players and, more particularly, to protective devices that function in a first mode in which the portable video device is carried and in a second mode in which the portable video device is supported for hands free viewing.
BACKGROUND OF THE INVENTION
[0004] Many small, portable electronic devices have the ability to display video images. In some cases, a portable electronic device is specifically designed for the display of video images and is physically constructed to facilitate the viewing of video images. In other cases, the portable electronic device is very small and/or is not specifically constructed for the purpose of displaying video images. For example, small, portable electronic devices such as cellular telephones and music players are provided with video screens on which video images can be viewed but which are not specifically designed for viewing video images. Small portable electronic devices such as cellular telephones and music players are typically held by hand when used and have no structural components that support the video screen thereof at a desirable viewing angle and location.
[0005] Additionally, small, portable electronic devices are typically handheld and thus are susceptible to being dropped, scratched, or otherwise damaged during normal use. Accordingly, for most small, electronic devices, protective cases, holders, or the like have been developed to protect the device from damage.
[0006] The need exists for improved protective systems and methods for portable video playing devices that function in a first mode in which the device is protected from physical damage and in a second mode in which the portable device may be supported in a hands free manner at a desirable viewing angle and location.
SUMMARY OF THE INVENTION
[0007] The present invention may take the form of a protective device for a video player comprising a video screen, comprising a structure defining a main chamber, a support opening, and a screen opening. The protective device operates in first and second modes. In the first mode, at least a portion of the video player is located within the main chamber such that the video screen is within the main chamber. The structure protects the video player the video screen is at least partly visible through the screen opening when the protective device is in the first mode. In the second mode, at least a portion of the video player extends through the support opening such that the structure supports the video player such that the video screen is located outside the main chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective, exploded view illustrating the insertion of a first example portable video player into a first example multi-mode protective device of the present invention;
[0009] FIG. 2 is a perspective view of the protective device of FIG. 1 carrying the first example video player in a first, carrying mode;
[0010] FIG. 3 is a perspective view of the first example protective device;
[0011] FIG. 4 is a rear elevation view of the first example protective device;
[0012] FIG. 5 is a bottom plan view of the first example protective device;
[0013] FIG. 6 is a side cutaway view taken along lines 6 - 6 in FIG. 4 ;
[0014] FIG. 7 is a side cutaway view of the first example protective device supporting the first example video player in a second, support mode;
[0015] FIG. 7A is a partial side cutaway view of an alternate configuration of the first example protective device operating in the second mode, where an engaging layer is formed on the protective device;
[0016] FIG. 8 is a rear elevation view of a second example multi-mode protective device of the present invention in a support mode, with a second example portable video player depicted in broken lines;
[0017] FIG. 9 is a side cutaway view taken along lines 9 - 9 in FIG. 8 ; and
[0018] FIG. 10 is a side cutaway view of the second example protective device supporting the second example video player in the support mode;
[0019] FIG. 11 is a rear elevation view of a third example multi-mode protective device of the present invention in a support mode, with the second example portable video player depicted in broken lines; and
[0020] FIG. 12 is a side cutaway view taken along lines 12 - 12 in FIG. 11 illustrating the third example protective device supporting the second example video player in the support mode.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Referring initially to FIGS. 1-7 of the drawing, depicted at 20 therein is a first example of a multi-mode protective device constructed in accordance with, and embodying, the principles of the present invention. The protective device 20 is adapted to carry a first example portable video player 22 in a first or carrying mode as shown in FIG. 2 and in a second or support mode as shown in FIG. 7 . The protective device 20 is thus a multi-mode device that allows the portable video player 22 to be carried in the first mode and supported for hands-free viewing in the second mode.
[0022] Referring initially to the example portable video player 22 , the video player 22 is not per se part of the present invention. As will become apparent from the following discussion, the present invention may be used in connection with portable video players in other configurations and with other controls, features, and input/output devices.
[0023] The first example portable video player 22 is an iPod digital audio and video player comprising a housing 24 defining a front wall 26 , a rear wall 28 , first and second side walls 30 and 32 , and first and second end walls 34 and 36 . The first example portable video player 22 comprises a screen 40 , first control 42 , second control 44 , first connector 46 , and second connector 48 . The screen 40 conventionally displays a user interface, graphics, and video. The first control 42 allows the user to enter commands in response to the user interface. The second control 44 is an ON/OFF slide switch. The first connector 46 allows the transfer of data between the video player 22 and another device such as a computer, docking station, digital camera, or the like. The second connector 48 is configured to allow an audio signal to be transmitted to a playback system such as headphones, amplifier, or the like.
[0024] In the model of iPod used as the first example digital video player, the screen 40 and first control 42 are mounted on the front wall 26 , the second connector 48 is mounted on the second end wall 36 , and the second control 44 and the first connector 46 are mounted on the first end wall 34 . The construction and operation of the first example video player 22 is not essential to an understanding of the present invention and will be described herein only to the extent necessary for a complete understanding of the present invention.
[0025] When the protective device 20 is used in the first mode, the portable video player 22 is at least partly surrounded by the protective device 20 to inhibit damage to the video player 22 during transportation and normal use. In this first mode, screen 40 is visible and the first and second controls 42 and 44 and first and second connectors 46 and 48 are accessible. When the protective device 20 is used in the second mode, the portable video player 22 is supported in an upright orientation with the screen 40 at a desirable angle and orientation for viewing. In this second mode, the first and second controls 42 and 44 and the first connector 46 are accessible.
[0026] The details of the example protective device 20 will now be described in further detail. The protective device 20 comprises a front panel 50 , a rear panel 52 , a first side panel 54 , a second side panel 56 , and an end panel 58 . The panels 50 - 58 define a player chamber 60 . One end of the protective device 20 defines a main opening 62 . A screen opening 64 and a control opening 66 are formed in the front panel 50 . A support opening 68 is formed in the rear panel 52 . A connector opening 70 is formed in the end panel 58 . First and second corner openings 72 and 74 are formed in the end panel 58 , while first and second corner notches 76 and 78 are formed in the first and second side panels 54 and 56 , respectively. First and second support edges 80 and 82 are defined by the rear panel 52 on opposite sides of the support opening 68 .
[0027] As perhaps best shown in FIGS. 1 and 2 , when the protective device 20 is used in its first, carrying mode, the example video player 22 is inserted into the player chamber 60 through the main opening 62 such that the front wall 26 engages the front panel 50 and the second end wall 36 engages the end panel 58 . In this first mode of using the device 20 , the screen 40 is visible through the screen opening 64 , the first control 42 is accessible through the control opening 66 , the second control 44 and first connector 46 are accessible through the main opening 62 , and the second connector 48 is accessible through the connector opening 70 .
[0028] In the first mode, the protective device 20 protects the video player 22 and also allows the player 22 to be used in a conventional manner. The video player 22 may be removed from the protective device 20 by gripping the first and/or second side walls 30 and 32 through the corner notches 76 and/or 78 and/or by pushing up on the second end wall 36 through one or both of the corner openings 72 and 74 .
[0029] When the protective device 20 is used in the second mode, the second end wall 36 of the player 22 is displaced through the support opening 68 in the rear panel 52 until the second end wall 36 engages the front panel 50 as shown in FIG. 7 . At this point, the video player 22 is released such that the front and rear walls 26 and 28 thereof engage the support edges 80 and 82 of the rear panel 52 .
[0030] With the video player engaging the front panel 50 and the support edges 80 and 82 in this second mode, the video player 22 is held at a desirable viewing angle with respect to the rear panel 52 . The protective device 20 may be placed on a support surface or otherwise supported in a horizontal manner as shown in FIG. 7 to allow hands-free viewing of the screen 40 . In addition, the first control 42 , the second control 44 , and the first connector 46 are all accessible in this second mode, as generally indicated in FIG. 7 .
[0031] Referring now for a moment to FIG. 7A of the drawing, depicted therein is an optional support layer 90 that may be applied to an inner surface 92 of the front wall 50 . The example support layer 90 is formed from a relatively high friction material that will not damage the finish of the video player 22 . A rubber, rubber-like, or gel-like material, perhaps with a tacky or gummy surface, may be used to increase friction between the video player 22 and the inner surface 92 of the front wall 50 while also not damaging the finish of the video player 22 . The increased friction provided by the example support layer 90 may allow more control of the viewing angle between the video player 22 and the rear surface 52 . Other examples of support layers, perhaps including notches or seats that correspond to different viewing angles, may be used in place of the example support layer 90 .
[0032] Turning now to FIGS. 8-10 of the drawing, depicted at 120 therein is a second example of a multi-mode protective device constructed in accordance with, and embodying, the principles of the present invention. The second example protective device 120 is adapted to carry a second example portable video player 122 in a first or carrying mode (similar to FIGS. 2 and 5 above) and in a second or support mode as represented in FIGS. 8 and 10 . The protective device 120 is thus also a multi-mode device that allows the portable video player 122 to be carried in the first mode and supported for hands-free viewing in the second mode.
[0033] Referring initially to the example portable video player 122 , the video player 122 is not per se part of the present invention. As with the first example protective device 20 , the present invention may be used in connection with portable video players in other configurations and with other controls, features, and input/output devices.
[0034] The first example portable video player 122 is an iPod digital audio and video player comprising a housing 124 defining a front wall 126 , a rear wall 128 , first and second side walls 130 and 132 , and first and second end walls 134 and 136 . The first example portable video player 122 comprises a screen 140 and one or more controls and/or connectors (not shown). The example screen 140 conventionally displays a user interface, graphics, and video. In the second example video player 122 , the screen 140 extends along almost the entire front wall 126 and is touch sensitive to form a control that allows user input in response to the user interface. The exact configuration of the controls and connectors is not important to the principles of the present invention except as will be described below.
[0035] In the model of iPod used as the second example digital video player 122 , the screen 140 is mounted on the front wall 126 . The screen is typically viewed with its long dimension horizontally arranged. The first side wall 130 thus lies under the screen 140 , while the second side wall 132 is above the screen 140 . The construction and operation of the second example video player 122 is not essential to an understanding of the present invention and will be described herein only to the extent necessary for a complete understanding of the present invention.
[0036] When the protective device 120 is used in the first mode, the portable video player 122 is at least partly surrounded by the protective device 120 to inhibit damage to the video player 122 during transportation and normal use. In this first mode, screen 140 is visible. When the protective device 120 is used in the second mode, the portable video player 122 is supported in an upright orientation with the screen 140 at a desirable angle and orientation for viewing. In the first and second modes, any other controls and connectors defined by the portable video player 122 should be accessible as necessary to operate the video player in that mode.
[0037] The details of the second example protective device 120 will now be described in further detail. The protective device 120 comprises a front panel 150 , a rear panel 152 , a first side panel 154 , a second side panel 156 , and an end panel 158 . The panels 150 - 158 define a player chamber 160 . One end of the protective device 120 defines a main opening 162 . A screen opening 164 is formed in the front panel 150 . A support opening 168 is formed in the rear panel 152 . A connector opening 170 is formed in the end panel 158 . First and second corner openings 172 and 174 are formed in the end panel 158 . First and second corner notches 176 and 178 are formed in the side panels 154 and 156 . First and second support edges 180 and 182 are defined by the rear panel 152 on opposite sides of the support opening 168 . First and second side notches 190 and 192 are formed in the side panels 154 and 156 , respectively. First and second support surfaces 194 and 196 are formed by the first and second side panels 154 and 156 at the first and second side notches 190 and 192 , respectively.
[0038] The protective device 120 is used in its first, carrying mode with the front wall 126 engaging the front panel 150 and the second end wall 136 engaging the end panel 158 . In this first mode of using the device 120 , the screen 140 is visible through the screen opening 164 . Additionally, any other controls or connectors formed on or defined by the video player are accessible as desirable when operating the video player 122 with the protective device 120 in this first mode. In the first mode, the protective device 120 protects the video player 122 and also allows the player 122 to be used in a conventional manner.
[0039] When the protective device 120 is used in the second mode, the first side wall 130 thereof is displaced through the support opening 168 in the rear panel 152 until the first side wall 130 engages the side panels 154 and 156 as shown in FIG. 10 . At this point, the video player 122 is released such that the front and rear walls 126 and 128 thereof engage the first and second support edges 180 and 182 of the rear panel 152 and the first side edge 130 engages the first and second support surfaces 194 and 196 .
[0040] With the video player engaging the front panel 150 and side panels 154 and 156 in this second mode, the video player 122 is held at a desirable viewing angle with respect to the rear surface 152 . The protective device 120 may be placed on a support surface or otherwise supported in a horizontal manner to allow hands-free viewing of the screen 140 . In addition, any controls or connectors should be accessible in this second mode.
[0041] Turning now to FIGS. 11 and 12 of the drawing, depicted at 220 therein is a third example of a multi-mode protective device constructed in accordance with, and embodying, the principles of the present invention. The third example protective device 220 is adapted to carry the second example portable video player 122 described above in a first or carrying mode and in a second or support mode as represented in FIGS. 11 and 12 . The protective device 220 is thus also a multi-mode device that allows the portable video player 222 to be carried in the first mode and supported for hands-free viewing in the second mode.
[0042] When the protective device 220 is used in the first mode, the portable video player 122 is at least partly surrounded by the protective device 220 to inhibit damage to the video player 122 during transportation and normal use. In this first mode, screen 140 is visible. When the protective device 220 is used in the second mode, the portable video player 122 is supported in an upright orientation with the screen 140 at a desirable angle and orientation for viewing. In the first and second modes, any other controls and connectors defined by the portable video player 122 should be accessible as necessary to operate the video player in that mode.
[0043] The details of the second example protective device 220 will now be described in further detail. The protective device 220 comprises a front panel 250 , a rear panel 252 , a first side panel 254 , a second side panel 256 , and an end panel 258 . The panels 250 - 258 define a player chamber 260 . One end of the protective device 220 defines a main opening 262 . A screen opening 264 is formed in the front panel 250 . A support opening 268 is formed in the rear panel 252 . A connector opening 270 is formed in the end panel 258 . First and second corner openings 272 and 274 are formed in the end panel 258 . First and second corner notches 276 and 278 are formed in the side panels 254 and 256 . First and second support edges 280 and 282 are defined by the rear panel 252 on opposite sides of the support opening 268 .
[0044] The protective device 220 is used in its first, carrying mode with the front wall 126 engaging the front panel 250 and the second end wall 136 engaging the end panel 258 . In this first mode of using the device 220 , the screen 140 is visible through the screen opening 264 . Additionally, any other controls or connectors formed on or defined by the video player are accessible as desirable when operating the video player 122 with the protective device 220 in this first mode. In the first mode, the protective device 220 protects the video player 122 and also allows the player 122 to be used in a conventional manner.
[0045] When the protective device 220 is used in the second mode, the first side wall 130 thereof is displaced through the support opening 268 in the rear panel 252 until the first side wall 130 engages the front panel 250 as shown in FIG. 12 . At this point, the video player 122 is released such that the front and rear walls 126 and 128 thereof engage the first and second support edges 280 and 282 of the rear panel 252 .
[0046] With the video player engaging the front panel 250 and rear panel 252 this second mode, the video player 122 is held at a desirable viewing angle with respect to the rear surface 252 . The protective device 220 may be placed on a support surface or otherwise supported in a horizontal manner to allow hands-free viewing of the screen 140 . In addition, any controls or connectors should be accessible in this second mode.
[0047] As generally indicated above, a protective device of the present invention may be configured based on the particular form factor and control and connector layout of a particular video player. | A protective device for a video player comprising a video screen, comprising a structure defining a main chamber, a support opening, and a screen opening. The protective device operates in first and second modes. In the first mode, at least a portion of the video player is located within the main chamber such that the video screen is within the main chamber. The structure protects the video player the video screen is at least partly visible through the screen opening when the protective device is in the first mode. In the second mode, at least a portion of the video player extends through the support opening such that the structure supports the video player such that the video screen is located outside the main chamber. | 0 |
BACKGROUND OF THE INVENTION
This invention relates to integrated circuits (ICs) generally, and to static CMOS (Complementary Metal Oxide Semiconductor) memory cells and logic circuits in particular. The number of circuits that are producible on a substrate of a given size is dependent on the number and size of the elements in each circuit. To reduce the size of such a circuit, many prior art methods redesign the circuit to reduce the number of elements or replace some of the larger circuit elements with smaller ones. For example, one method reduces an eight-transistor memory cell to the six-transistor cell shown in FIG. 1A (see, for example, "Digital Circuits and Logic Design" by S. C. Lee, Prentice-Hall, Englewood Cliffs, N.J., 1976, pages 569-571).
In the memory cell of FIG. 1A, the six transistors act as gates to control the voltages on a pair of nodes 10 and 11. A control transistor 12 controls access from a bit line to node 10, while another control transistor 13 controls access from a bit line to node 11. The memory state of this cell is represented by the voltage on node 10--a "1" is represented by a voltage within a range near a voltage V 1 and a "0" by a voltage within a range near a voltage V 2 . Because current leakage across transistor 12 is generally unavoidable, a set of logic transistors 14, 15, 16 and 17 is provided to control access to nodes 10 and 11 from a voltage source 18 of voltage V 1 and a voltage source 19 of voltage V 2 . This arrangement maintains the voltage stored on node 10 at its appropriate value. In order to act as a gate controlling access to node 10, each of the transistors 12, 14 and 16 must function to make any preselected path to node 10 have much higher conductance than the other paths. This requires that the on state conductance g on of each transistor connected to node 10 must be much greater than the off state conductance g off of the other transistors connected to node 10. Comparable constraints apply to the transistors connected to node 11. In operation, the voltage on node 10 is held within a range near V 1 or V 2 depending on whether the conductance of transistor 14 is respectively much greater or much less than the conductance of transistor 16. Transistor 16 can therefore be replaced with a resistor of conductance g r in the range:
g.sub.off <<g.sub.r <<g.sub.on
without changing the operation of this memory cell. Likewise, transistor 15 or 17 can be replaced with a resistor. (See the article entitled "Resistance-CMOS Circuits" by H. Oguey and E. Vittoz in IEEE Journal of Solid State Circuits, Vol. SC-12, No. 3, June, 1977, page 283.) This procedure provides some design flexibility, but does not reduce the overall number of elements in the circuit.
SUMMARY OF THE INVENTION
The present invention discloses a method and a device for reducing the circuit size of a class of circuits by requiring selected transistor junctions to be leaky to thereby perform the functions of other elements which can therefore be eliminated from the circuits. A circuit in the class is characterized as having a node to which are electrically connected: (1) a first voltage source through a first electrical path, (2) a second voltage source through a second electrical path and (3) a control transistor which is responsive to applied control signals. The first electrical path contains a logic transistor which is responsive to logic signals and which cooperates with the other circuit elements to control the voltage on the node to represent a digital logic state.
In general, the leakage current across the control transistor junction between its bulk and its source or drain electrode (the source and drain being collectively referred to as doped regions) which is electrically connected to the node will be utilized. Such an electrode will be referred to herein as the selected electrode, the junction will be called the selected junction and the conductance of the selected junction under reverse bias will be called the leakage conductance. In general the current to and from the node is due not only to the conductance of the transistors connected to the node, but also to the conductance of their parasitic elements. According to the method, a "leaky" control transistor is employed having a leakage conductance in the range between the off state conductance and on state conductance of the combination of logic transistors and all parasitic elements connected to the node. This leakage path performs its intended functions as well as those of the second electrical path. Some or all of the circuit elements on the second electrical path are then eliminated, thereby making possible a circuit of identical function, but of smaller physical size.
DESCRIPTION OF THE DRAWINGS
FIG. 1A shows a prior art memory cell to which the disclosed method is applicable.
FIG. 1B shows a circuit derived from the circuit in FIG. 1A by the present method.
FIG. 2 shows the parts of a MOSFET to clarify the role of the drain junction in the method.
FIG. 3A shows a prior art circuit derivable from the circuit in FIG. 1A by replacing two transistors with two resistors.
FIG. 3B shows a circuit derived from the circuit in FIG. 3A by the present method.
FIG. 4A shows a circuit in which a pair of series transistors can be eliminated in accordance with the present method.
FIG. 4B shows a circuit derived from the circuit in FIG. 4A by the present method.
FIG. 5A shows a circuit in which a pair of parallel transistors can be eliminated in accordance with the present method.
FIG. 5B shows a circuit derived from the circuit in FIG. 5A by the present method.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is a method for reducing the circuit size of a class of integrated circuits by selecting certain transistor junctions to be leaky, thereby performing the function of other circuit elements which can then be eliminated. The nature of the junctions and leakage currents can be seen by referring to the channel MOSFET shown in FIG. 2.
FIG. 2 shows a transistor having a source junction 21 between a source 22 and a bulk region 23 and also a drain junction 24 between a drain 25 and bulk 23 (the source and drain being collectively referred to as doped regions). A voltage V b is applied to the bulk region by voltage source 26 to prevent these junctions from becoming forward biased under operating conditions. A gate electrode 27 controls current flow between source 22 and drain 25. In practice the source and drain junctions function as reverse biased diode junctions. Under reverse bias, a leakage current flows across the drain junction indicating a typical leakage conductance of about 10 -13 mho for a 6 volt reverse bias. This leakage current has caused problems in prior circuits so that prior art methods typically seek to reduce or compensate for such leakage currents. For example, it was noted in the Background that in the prior art memory cell of FIG. 1A there is generally an unavoidable leakage current from node 10 to other nodes. A set of logic transistors 14, 15, 16 and 17 are therefore required to access nodes 10 and 11 from a first voltage source 18 of voltage V 1 and a second voltage source 19 of voltage V 2 to maintain the proper value of the voltage on node 10. A transistor will herein be referred to as being of "A" or "B" conduction type depending on whether, under operating conditions, a forward bias across its source and drain junctions can be prevented by biasing the bulk at voltage V 1 or V 2 respectively.
As shown in the Background, transistor 16 can be replaced by a resistor which has a conductance g r which is much greater than the off state conductance g off of transistors 12 and 14, and much less than their on state conductance g on . Typical values for g off and g on are 10 -13 mho and 10 -4 mho, respectively, so that there is a wide range of suitable values for g r . The circuit which results by replacing transistors 14 and 15 with resistors 34 and 35 is shown in FIG. 3A. (In general, the first digit in the designation of a circuit element will represent the number of the figure showing that circuit. Corresponding elements in other figures will be designated with corresponding last digits.) Such a circuit still employs the same number of elements as the circuit in FIG. 1A.
Circuits such as those shown in FIG. 1A can be replaced by circuits of greater simplicity than that shown in FIG. 3A. The voltage of the bulk bias of transistor 12 can be chosen to be V 2 . For such a choice of bias, the leakage path across the drain junction of transistor 12 represents an existing electrical path from "V 2 " or "the second voltage source" to node 10. Transistor 16 can therefore be eliminated if the conductance g 10 of this leakage path is chosen to lie in the range:
10.sup.-13 mho˜g.sub.off <<g.sub.10 <<g.sub.on ˜10.sup.-4 mho.
Transistor 17 can similarly be eliminated after an equivalent selection of the leakage conductance of the selected junction of transistor 13.
In a similar but more complicated manner transistor 14 can be eliminated in lieu of transistor 16. First, a leakage path from node 10 to voltage source 18 is created by replacing transistor 12 with a transistor of opposite conduction type having a leaky selected junction and having its bulk biased at V 1 . The leakage conductance of its drain junction now provides a resistive path from voltage source 18 to node 10 thereby allowing transistor 14 to be eliminated. FIGS. 1B and 3B show circuits which result by this method from circuits 1A and 3A respectively. Diodes 16' and 17' of FIG. 1B represent the selected junctions of transistors 12' and 13' respectively which provide electrical paths from voltage source 19' to nodes 10' and 11'. Likewise, in FIG. 3B, diodes 34' and 35' represent the selected junctions of transistors 32' and 33' respectively, which provide electrical paths from voltage source 38' to nodes 30' and 31'.
There are also circuits in which several elements can be eliminated by exploiting a single leaky control transistor junction. For example, FIG. 4A shows a circuit in which two series elements can be eliminated and FIG. 5A shows a circuit in which two parallel elements can be eliminated. In FIG. 4A, after replacing a transistor 42 with a transistor 42' having a leaky drain junction, a pair of transistors 46 and 47 can be eliminated to give the circuit in FIG. 4B. Diode 46' represents the drain junction of transistor 42'. In FIG. 5A, after employing a transistor 52' having a leaky selected junction, a pair of transistors 56 and 57 can be eliminated to give the circuit in FIG. 5B. Diode 56' represents the drain junction of transistor 52'. In the same manner that existing circuits can be reduced by exploiting leakage currents, new smaller circuits can be designed by exploiting leaky transistor junctions.
A preferred method for producing the "leaky junctions" of the invention is by ion implanting "good" junctions. Typically, the ions used for implantation are selected to disrupt the crystal lattice. Neon has been found to be a useful choice. The lattice defects create states of energy in the gap between the valence and conduction energy bands so that electron-hole pairs can be more easily formed. Since leakage current across a transistor junction is due in part to electron-hole pairs formed in the junction region, the energy of the bombarding ions is generally selected such that some implant damage is introduced in the bulk to electrode space charge region. This damage makes the junction leaky without notably changing the junction's other properties so that the implanted transistor junctions continue to perform their prior functions as well as the functions of the eliminated elements.
The leakage conductance can be accurately controlled by controlling the area and periphery of junction exposed to damage, the number and kind of ions implanted and the ion acceleration potential. For example, a dose of 3×10 14 Neon ions per cm 2 at 150 mev impact energy, produces a conductance of about 10 -8 mho in a 900 μm by 900 μm p+ junction. To minimize power drain through the leaky junction, the conductance of the leakage path should be chosen as close to g c as allows the circuit to continue functioning properly. Such a conductance is easy to achieve by enhancement from an initial value of g c . | A method and device are disclosed for reducing the circuit size of a class of circuits including many memory cells and logic circuits. Selected drain to bulk or source to bulk transistor junctions are made leaky. The leaky junctions perform their intended (non-leaky) functions as well as the functions of certain other circuit elements. These other elements may therefore be eliminated from the circuit. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 09/885,850, filed Jun. 20, 2001, now U.S. Pat. No. 6,571,871, which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an expandable sand screen. More particularly the present invention relates to an expandable sand screen that permits fracturing of a hydrocarbon bearing formation after the well screen is expanded in a wellbore.
2. Description of Related Art
Hydrocarbon wells are typically formed with a central wellbore that is supported by steel casing. The casing lines the borehole in the earth and the annular area created between the casing and the borehole is filled with cement to further support and form the wellbore.
While some wells are produced by simply perforating the casing of the central wellbore and collecting the hydrocarbons, wells routinely include portions of wellbore that are left open or unlined with casing. Because they are left open, hydrocarbons in an adjacent formation migrate into these wellbores where they are affected along a perforated tubular or sand screen having apertures in its wall and some kind of filtering material to prevent sand and other particles from entering. The sand screen is attached to production tubing at an upper end and the hydrocarbons travel to the surface of the well via the tubing. In this specification “open” and “horizontal” wellbore refers to an unlined bore hole or wellbore.
Because open wellbores have no support provided along their walls, and because the formations accessed by these wellbores have a tendency to produce sand and particulate matter in quantities that hamper production along a sand screen, open wellbores are often treated by fracturing and packing. Fracturing a wellbore or formation means subjecting the walls of the wellbore and the formation to high pressure solids and/or fluids that are intended to penetrate the formation and stimulate its production by increasing and enlarging the fluid paths towards the wellbore. Packing a wellbore refers to a slurry of sand that is injected into an annular area between the sand screen and the walls of the wellbore to support the wellbore and provide additional filtering to the hydrocarbons. Fracturing and packing can be performed simultaneously. A cross-over tool is typically utilized to direct the fracturing/packing material towards the annulus of the open wellbore while returning fluid is circulated up the interior of the screen and returns to the surface of the well in an annular area of the central wellbore.
There are problems associated with the packing of an open wellbore. One such problem relates to sand bridges or obstructions which form in the annulus between the sand screen and the wall of the wellbore. These sand bridges can form anywhere along the wellbore and they prevent the flow of injected material as it travels along the annulus. The result is an incomplete fracturing/packing job that leaves some portion of the sand screen exposed to particulate matter and in some cases, high velocity particles that can damage the screen.
Today there exists a sand screen that can be expanded in the wellbore. This expandable sand screen “ESS” consists of a perforated base pipe, woven filtering material and a protective, perforated outer shroud. Both the base pipe and the outer shroud are expandable and the woven filter is typically arranged over the base pipe in sheets that partially cover one another and slide across one another as the ESS is expanded. The foregoing arrangement of expandable sand screen is known in the art and is described in U.S. Pat. No. 5,901,789 which is incorporated by reference herein in its entirety. Expandable sand screen is expanded by a cone-shaped object urged along its inner bore or by an expander tool having radially outward extending rollers that are fluid powered from a tubular string. Using expander means like these, the ESS is subjected to outwardly radial forces that urge the walls of the ESS past their elastic limit, thereby increasing the inner and outer diameter of the ESS.
The biggest advantage to the use of expandable sand screen in an open wellbore like the one described herein is that once expanded, the annular area between the screen and the wellbore is mostly eliminated and with it the need for a gravel pack. Typically, the ESS is expanded to a point where its outer wall places a stress on the wall of the wellbore, thereby providing support to the walls of the wellbore to prevent dislocation of particles.
While the ESS removes the need for packing the wellbore with sand, it does not eliminate the need to fracture the formation in order to improve production. Fracturing prior to expanding the screen in the wellbore is not realistic because the particulate matter, like the sand used in the fracturing will remain in the annulus and hamper uniform expansion of the screen. Fracturing after expansion of the expandable sand screen is not possible because, as explained herein, the annular path for the fracturing material has been eliminated.
There is a need therefore for an expandable sand screen for use in a wellbore to be fractured. There is a further need for an expandable sand screen that can be expanded prior to the fracturing of the wellbore surrounding the screen. There is yet a further need for an expandable sand screen that forms a path or conduit for the flow of fracturing material along its outer surface after it has been expanded.
SUMMARY OF THE INVENTION
The present invention provides apparatus and methods for expanding an expandable sand screen in an open wellbore and then fracturing the wellbore. In one aspect of the invention, an expandable sand screen includes a perforated inner pipe and outer shroud. The outer shroud includes a plurality of longitudinal channels that retain their general shape after the expandable sand screen is expanded. In the expanded state, the channels provide a fluid conduit along an area between the screen and the wall of the wellbore. In a subsequent fracturing operation, a slurry travels along the conduits permitting communication of the slurry with hydrocarbon bearing formations to effectively fracture the formation. In another aspect, a method of fracturing includes expanding an expandable well screen in a wellbore whereby the expanded screen provides longitudinal channels in communication with the hydrocarbon bearing formation. Thereafter, fracturing slurry is injected and travels along the channels, thereby exposing the slurry to the formation. In yet another aspect of the invention, joints of the ESS are assembled together into sections and the channels on the outer surface of each joint are aligned to ensure that the longitudinal channels are aligned throughout the ESS section.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
FIG. 1 is a section view showing an open, horizontal wellbore with an expandable sand screen disposed therein.
FIG. 2 is an exploded view of an expander tool.
FIG. 3 is a section view of the expandable sand screen in an unexpanded state.
FIG. 4 is a section view of the wellbore with the screen partially expanded.
FIG. 5 is a section view of the expandable sand screen in an expanded state.
FIG. 6 is a section view of the wellbore being treated with material injected from the surface of the well through a cross-over tool.
FIG. 7 is a section view of the wellbore tied back to the surface of the wall with a production tubing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a section view of a wellbore 200 with an expandable sand screen 210 according to the present invention disposed therein. The wellbore includes a central wellbore which is lined with casing 215 . The annular area between the casing and the earth is filled with cement 220 as is typical in well completion. Extending from the central wellbore is an open, horizontal wellbore 225 . A formation 226 is shown adjacent the wellbore 225 . Disposed in the open wellbore is an expandable sand screen (ESS) 210 . As illustrated in FIG. 1 , the ESS 210 is run into the wellbore on a tubular run-in string 230 . Disposed at the end of the run-in string is an expander tool 100 . In the embodiment shown, the expander tool 100 is initially fixed to the expandable sand screen 210 with a temporary connection 235 like a shearable connection or some other temporary mechanical means. Typically, the ESS 210 is located at the lower end of a liner 218 which is run into the well and hung from the lower portion of the casing 215 by some conventional slip means. Below the liner top, the outer diameter of the liner 218 is reduced to a diameter essentially equal to the diameter of the ESS.
FIG. 2 is an exploded view of an exemplary expansion tool 100 . The expansion tool 100 has a body 102 which is hollow and generally tubular with connectors 104 and 106 for connection to other components (not shown) of a downhole assembly. The connectors 104 and 106 are of a reduced diameter compared to the outside diameter of the longitudinally central body part of the tool 100 . The central body part has three recesses 114 to hold a respective roller 116 . Each of the recesses 114 has parallel sides and extends radially from a radially perforated tubular core (not shown) of the tool 100 . Each of the mutually identical rollers 116 is somewhat cylindrical and barreled. Each of the rollers 116 is mounted by means of an axle 118 at each end of the respective roller and the axles are mounted in slidable pistons 120 . The rollers are arranged for rotation about a respective rotational axis which is parallel to the longitudinal axis of the tool 100 and radially offset therefrom at 120-degree mutual circumferential separations around the central body. The axles 118 are formed as integral end members of the rollers and the pistons 120 are radially slidable, one piston 120 being slidably sealed within each radially extended recess 114 . The inner end of each piston 120 is exposed to the pressure of fluid within the hollow core of the tool 100 by way of the radial perforations in the tubular core. In this manner, pressurized fluid provided from the surface of the well, via a tubular, can actuate the pistons 120 and cause them to extend outward whereby the rollers contact the inner wall of a tubular to be expanded.
FIG. 3 is a section view of the expandable sand screen 210 of the present invention in a wellbore 200 prior to expansion. The ESS includes a base pipe 240 having perforation 242 formed therein, woven filter material 245 and an outer shroud 250 having perforations 255 formed therein and also having outwardly formed longitudinal channels 260 formed thereupon. The channels 260 are formed by bending the surface of the outer shroud 250 between perforations 255 to create two sides 265 , 270 and a bottom portion 275 . In the preferred embodiment illustrated in FIG. 3 , the bottom portion of each channel is welded or otherwise attached to the base pipe in at least one location 280 . The woven filter material 245 is held between the bottom 275 of the channel 260 and the base pipe 240 . The outer shroud 250 may be formed by any well-known metal working means including pressing and bending. A longitudinal seam (not shown) is formed by the cylindrical shroud after it is wrapped around the base pipe and filter material and its free ends are connected.
FIG. 4 is a section view illustrating the wellbore 200 and the ESS 210 partially expanded therein. As shown in the figure, the expansion tool 100 has been activated with its rollers 116 contacting the inner wall of base pipe 240 and applying an outward radial force thereto. Typically, the temporary connection 235 between the expander tool 100 and the ESS 210 is disengaged as the expander tool is actuated and thereafter, the expander tool moves independently of the expandable sand screen 210 . By using the run-in string 230 to move the expander tool axially and rotationally within the ESS, the ESS 210 can be circumferentially expanded into or nearly into contact with the wellbore therearound.
FIG. 5 is a section view illustrating the expandable sand screen 210 of the present invention after it has been expanded in a wellbore 200 . Radial force applied to the inner wall of the base pipe 240 has forced the pipe past its elastic limits and also expanded the diameter of the base pipe perforations 242 . Also expanded is the shroud 250 with its formed channels 260 . As shown in the figure, the shroud is expanded to a point wherein the upper edges of the sides 265 , 270 of the channel 260 are either in contact or almost in contact with the wellbore 200 . The decision relating to contact between the expanded sand screen in a wellbore depends upon the needs of the user. Contact between the screen 210 and the wellbore 200 can place a slight stress on the wellbore and reduce the risk of particulate matter entering the wellbore. On the other hand, leaving a slight space between the edges of the channel and the wellbore leaves a greater fluid path for fracturing material to reach areas of the wellbore between the channels.
FIG. 6 is a section view of the wellbore 200 illustrating an apparatus used to fracture the well after the ESS 210 has been expanded. As illustrated, a string of tubulars 300 is inserted into the top of the liner. An assembly at the lower end of the string of tubulars is typical of one used in fracturing operations and includes a cross-over tool 310 made up of an exit port 315 (not shown) permitting fluids to exit the tubular and a first and second packer 320 , 325 disposed on either side of the exiting port to isolate the port from the annular area between the liner and the run-in string. A sliding sleeve (not shown) on the liner permits fluid communication between the interior of the string 300 and the exterior of the liner. As illustrated by arrows 330 , a slurry of fracturing and/or packing material is injected from the surface of the well down the tubular string 300 . At some predetermined location below the top of the liner 218 , the cross-over tool 310 permits the material to flow to an annular area outside of the liner and the expanded sand screen. In this manner, the material flows to the outer surface of the expanded sand screen and longitudinally flows along the channels 260 formed on the exterior of the ESS 210 . The particulate material is left within the annular area and within fractures extending outwardly from the wellbore and fluid (illustrated by arrows 335 ) is returned to the surface of the well in the interior of the string and subsequently, via the annular area between the string 300 and the casing 215 of the central wellbore. In use, a slurry of sand and gel or other fracturing material at an elevated pressure is carried into the central wellbore 200 in a tubular. Using a cross-over tool or other apparatus, the slurry is directed from the tubular to the outer surface of the expanded sand screen where it travels from a heel 226 of the wellbore 225 towards the toe 227 thereof. In this manner, the walls of the wellbore 225 and the formation 226 therearound are exposed to the high pressure slurry via the channels 260 formed on the outer surface of the shroud 250 . Return fluid is carried back towards the surface of the well in the interior of the base pipe 240 .
One method of utilizing the expandable sand screen of the invention is as follows: A section of expandable sand screen 210 is formed at the surface of a well to an appropriate length by threading joints of screen together. The channels 260 formed in the shroud 250 of each subsequent joint are aligned as the joints are assembled together. The unexpanded section of ESS is then run into the wellbore 200 on a tubular string having an expander tool 100 disposed at the end thereof. The expander tool, or alternatively the run-in string adjacent the tool, is temporarily connected to the expandable sand screen 210 with a temporary connection 235 . As the ESS 210 reaches its desired location in the wellbore 200 , the expander tool 100 is actuated and the ESS is expanded in at least two points about is circumference. In this manner, the ESS is anchored in the wellbore. By providing a pulling, pushing or rotational movement to the string and expander tool, the temporary connection 235 between the tool 100 and the sand screen 210 is disengaged and the activated expander tool can move independently of the screen 210 .
By moving the actuated tool 100 within the sand screen, both rotationally and axially, the screen is expanded to take on an appearance illustrated in FIGS. 5 and 7 . With the screen 210 in its expanded position within the wellbore 200 , the expansion tool 100 and run-in string are removed and a tubular having a cross-over tool at the end thereof is run into the wellbore. The cross-over tool permits fluid communication between the tubular and the channels 260 on the outer surface of the expanded screen 210 . As pressurized slurry travels down the tubular, it is directed by the cross-over tool to the longitudinal channels and is placed in communication with the wellbore.
FIG. 7 is a section view of a central 200 and a lateral 225 wellbore after the ESS 210 has been expanded into position and the well is producing hydrocarbons. A string of tubulars 400 like a string of production tubing has been inserted into the upper portion of the liner 218 and sealed therein with a packer 410 . This sealing and arrangement between the liner and the production tubing ties the liner back to the surface of the well. Hydrocarbons illustrated as arrows 415 migrate into the expanded sand screen 210 where they are collected in the interior of the screen and the liner. The hydrocarbons then move directly towards the surface of the well in the conduit provided by production tubing string 400 .
While the liner 218 and ESS 210 are shown run into the wellbore on a run in string of tubulars, it will be understood that the apparatus of the invention can be transported into the wellbore using any number of means including coiled tubing. For example, using coiled tubing and a mud motor disposed thereupon, the apparatus can be utilized with rotation provided by the mud motor. A fluid powered tractor can be used to provide axial movement of the apparatus into the lateral wellbore 225 . These variations are within the scope of the invention.
As the foregoing demonstrates, the present invention provides an apparatus and methods to utilize expandable sand screen in an open wellbore in a way that minimizes the need to fill an annular area around the screen with gravel. Additionally, the invention provides for an effective fracturing of an open wellbore without the risk of sand bridges being formed between the screen and the walls of the wellbore.
The apparatus described herein is a sand screen intended to filter hydrocarbons. However, the structure described relating to the grooves could be utilized with any expandable wellbore component leaving a fluid path along the outer surface thereof after expansion. Other uses include water wells and injection wells.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. | The present invention provides apparatus and methods for expanding an expandable sand screen in the wellbore and then fracturing the wellbore. In one aspect of the invention, an expandable sand screen includes a perforated inner pipe and outer shroud. The outer shroud includes a plurality of longitudinal channels that retain their general shape after the expandable sand screen is expanded. In the expanded state, the channels provide a fluid conduit along an area between the screen and the wall of the wellbore. In a subsequent fracturing operation, slurry travels along the conduits permitting communication of the fracturing slurry with hydrocarbon bearing formations. | 4 |
FIELD OF THE INVENTION
This invention relates to a method for separating isopropyl ether from isopropanol using certain higher boiling liquids as the extractive agent in extractive distillation.
DESCRIPTION OF PRIOR ART
Extractive distillation is the method of separating close boiling compounds or azeotropes by carrying out the distillation in a multiplate rectification column in the presence of an added liquid or liquid mixture, said liquid(s) having a boiling point higher than the compounds being separated. The extractive agent is introduced near the top of the column and flows downward until it reaches the stillpot or reboiler. Its presence on each plate of the rectification column alters the relative volatility of the close boiling compounds in a direction to make the separation on each plate greater and thus requires either fewer plates to effect the same separation or make possible a greater degree of separation with the same number of plates. When the compounds to be separated normally form an azeotrope, the proper agents will cause them to boil separately during extractive distillation and thus make possible a separation in a rectification column that cannot be done at all when no agent is present. The extractive agent should boil higher than any of the close boiling liquids being separated and not form minimum azeotropes with them. Usually the extractive agent is introduced a few plates from the top of the column to insure that none of the extractive agent is carried over with the component of highest vapor pressure. This usually requires that the extractive agent boil twenty Centigrade degrees or more higher than the lowest boiling component.
At the bottom of a continuous column, the less volatile components of the close boiling mixtures and the extractive agent are continuously removed from the column. The usual methods of separation of these two components are the use of another rectification column, cooling and phase separation, or solvent extraction.
The breaking of this azeotrope by extractive distillation is a new concept. One of the first applications of this concept might be the breaking of the ethanol-water azeotrope. J. Schneible, U.S. Pat. No. 1,469,447 used glycerol; P. V. Smith & C. S. Carlson, U.S. Pat. No. 2,559,519 employed ethoxyethanol and butoxyethanol for this purpose and W. E. Catterall, U.S. Pat. No. 2,591,672 reported gasoline as being effective. These are dehydrations and operate more conventionally as a solvent extraction process rather than an extractive distillation. Smith, U.S. Pat. No. 2,559,520 described an extractive distillation process for separating one alcohol from another alcohol, specifically ethanol from isopropanol. Finkel, U.S. Pat. No. 4,469,491 described an extractive distillation process for separating diisopropyl ether from similar boiling hydrocarbons.
The most common method of manufacturing isopropanol is by the hydration of propylene using sulfuric acid as the catalyst. However before the isopropanol can be removed from the reaction mixture, some of its reacts with the sulfuric acid to form isopropyl ether. Thus isopropanol made by this method invariably contains some isopropyl ether as an impurity. Normally a mixture of several solvents are separated and recovered by fractionation in a multiplate rectification column and the ease of separation depends upon the difference in boiling points of the compounds to be separated. However isopropanol, isopropyl ether and water form three binary azeotropes and one ternary azeotrope as shown in Table I. Thus any mixture containing these three compounds subjected to rectification will produce an overhead product boiling at 61.6° C. and containing 4.7% water, 7.3% isopropanol and 88% isopropyl ether.
TABLE I______________________________________Azeotropes of Isopropyl Ether, Isopropanol and Water. B.P., AzeotropeCompounds °C. Composition, Wt. %______________________________________Water 100Isopropanol 82.5Isopropyl ether 69.0Water-Isopropanol 80.3 12.6 87.4Isopropanol-Isopropyl ether 66.2 16.3 83.7Water-Isopropyl ether 62.2 4.5 95.5Water-Isopropanol-Isopropyl ether 61.6 4.7 7.3 88.0______________________________________
Extractive distillation would be an attractive method of effecting the separation of isopropyl ether from isopropanol and water if agents can be found that (1) will break the isopropyl ether-isopropanol-water azeotrope and (2) are easy to recover from the isopropanol and water, that is, form no azeotrope with isopropanol and boil sufficiently above isopropanol to make the separation by rectification possible with only a few theoretical plates.
Extractive distillation typically requires the addition of an equal amount to twice as much extractive agent as the isopropyl ether-isopropanol-water on each plate of the rectification column. The extractive agent should be heated to about the same temperature as the plate into which it is introduced. Thus extractive distillation imposes an additional heat requirement on the column as well as somewhat larger plates. However this is less than the increase occasioned by the additional agents required in azeotropic distillation. Another consideration in the selection of the extractive distillation agent is its recovery from the bottoms product. The usual method is rectification in another column. In order to keep the cost of this operation to a minimum, an appreciable boiling point difference between the compound being separated and the extractive agent is desirable. It is also desirable that the extractive agent be miscible with isopropanol otherwise it will form a two phase azeotrope with the isopropanol in the recovery column and some other method of separation will have to be used, as well as having a deleterious effect on the extractive distillation.
The ratios shown in Table II are the parts by weight of extractive agent use per part of isopropyl ether-isopropanol-water azeotrope and the two relative volatilities correspond to the two different ratios. For example in Table II, one part of isopropyl ether-isopropanol-water azeotrope with one part of diethylene glycol methyl ether gives a relative volatility of 2.72, 6/5 parts of diethylene glycol methyl ether gives 2.17. One half part of diethylene glycol diethyl ether mixed with one half part of diethylene glycol ethyl ether with one part of isopropyl ether-isopropanol-water azeotrope gives a relative volatility of 2.01, 3/5 parts of diethylene glycol diethyl ether plus 3/5 parts of diethylene glycol ethyl ether gives 1.60.
Several of the compounds and mixtures listed in Table II and whose relative volatility had been determined in the vapor-liquid equilibrium still, were then evaluated in a glass perforated plate rectification column possessing 4.5 theoretical plates. The results are listed in Table III. The isopropyl ether-isopropanol-water mixture studied contained 10% isopropyl ether, 85% isopropanol, 5% water. The ternary azeotrope contains 88.0 wt.% isopropyl ether, 7.3 wt.% isopropanol and 4.7 wt.% water. What is remarkable is that pure isopropyl ether comes off as overhead product. In every case the feed or bottoms product contained less than 88% isopropyl ether and in every case the overhead is richer than 88% isopropyl ether. Without extractive distillation agents, the overhead would be the azeotrope, 88% isopropyl ether. This proves that the extractive agent is negating the azeotrope and makes the rectification proceed as if the azeotrope no longer existed and brings the more volatile component, isopropyl ether, out as overhead. It is our belief that this is the first time that this has been reported for this azeotrope.
The data in Table III was obtained in the following manner. The charge designated "blank" was 10% isopropyl ether, 85% isopropanol and 5% water and after 1.5 hours operation in the 4.5 theoretical plate column, the relative volatility of the separation between the isopropyl ether-isopropanol-water azeotrope and isopropanol was 3.28. The remaining data is for the extractive distillation agents designated. Here we have negated the azeotrope and brought out the pure isopropyl ether as overhead. The temperature of the overhead approaches 63° C., the boiling point of pure isopropyl ether at 630 mm. Hg.
OBJECTIVE OF THE INVENTION
The object of this invention is to provide a process or method of extractive distillation that will enhance the relative volatility of isopropyl ether from isopropanol and water in their separation in a rectification column. It is a further object of this invention to identify suitable extractive distillation agents which will eliminate the isopropyl ether-isopropanol-water azeotrope and make possible the production of pure isopropyl ether and isopropanol by rectification. It is a further object of this invention to identify organic compounds which, in addition to the above constraints, are stable, can be separated from isopropanol and water by rectification with relatively few plates and can be recycled to the extractive distillation column and reused with little decomposition.
SUMMARY OF THE INVENTION
The objects of this invention are provided by a process for separating isopropyl ether from isopropanol and water which entails the use of certain oxygenated organic compounds as the agent in extractive distillation.
DETAILED DESCRIPTION OF THE INVENTION
We have discovered that certain oxygenated organic compounds, some individually but principally as mixtures, will effectively negate the isopropyl ether-isopropanol-water azeotrope and permit the separation of oure isopropyl ether from isopropanol and water by rectification when employed as the agent in extractive distillation. Table II lists the compounds, mixtures and approximate proportions that we have found to be effective. The data in Table II was obtained in a vapor-liquid equilibrium still. In each case, the starting material was the isopropyl ether-isopropanol-water azeotrope. The ratios are the parts by weight of extractive agent used per part of isopropyl ether-isopropanol-water azeotrope. The relative volatilities are listed for each of the two ratios employed.
The compounds that are effective as extractive distillation agents when used alone are ethylene glycol hexyl ether, propylene glycol methyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol diethyl ether, propylene glycol and ethylene glycol. The compounds that are effective when used in mixtures of two or more components are propylene glycol ethyl ether, diethylene glycol butyl ether and diethylene glycol hexyl ether.
TABLE II______________________________________Extractive Distillation Agents Which Are Effective InSeparating Isopropyl Ether As Overhead From Isopropanol RelativeCompounds Ratios Volatilities______________________________________Diethylene glycol methyl ether 1 6/5 2.72 2.17Diethylene glycol ethyl ether 1 6/5 3.55 2.30Ethylene glycol hexyl ether 1 6/5 2.00 1.33Propylene glycol methyl ether 1 6/5 1.72 1.35Diethylene glycol butyl ether 1 6/5 1.55 1.46Diethylene glycol diethyl ether, (1/2).sup.2 (3/5).sup.2 2.01 1.60Diethylene glycol ethyl etherDiethylene glycol diethyl ether, (1/2).sup.2 (3/5).sup.2 1.41 1.62Propylene glycol ethyl etherDiethylene glycol butyl ether, (1/2).sup.2 (3/5).sup.2 1.10 1.52Diethylene glycol hexyl ether______________________________________
TABLE III______________________________________Data From Runs Made In Rectification Column. Overhead Phases in RelativeCompounds Temp. °C. Overhead Volatility______________________________________Blank (no agent) 56.8 2 *Diethylene glycol diethyl ether 62.6 2 3.20Propylene glycol 63.2 1 4.88Ethylene glycol 62.2 2 5.18______________________________________ Notes: *did not negate the azeotrope Feed composition was 50 gr. isopropyl ether, 425 gr. isopropanol, 25 gr. water.
THE USEFULNESS OF THE INVENTION
The usefulness or utility of this invention can be demonstrated by referring to the data presented in Tables II & III. All of the successful extractive distillation agents show that isopropyl ether can be removed from its ternary minimum azeotrope with isopropanol and water by means of distillation in a rectification column and that the ease of separation as measured by relative volatility is considerable. Without the extractive distillation agents, no improvement above the azeotrope composition will occur in the rectification column. The data also show that the most attractive agents will operate at a boilup rate low enough to make this a useful and efficient method of recovering high purity isopropyl ether from any mixture with isopropanol and water including the ternary minimum azeotrope. The stability of the compounds used and the boiling point difference is such that complete recovery and recycle is obtainable by a simple distillation and the amount required for make-up is small.
WORKING EXAMPLES
Example 1: The isopropyl ether-isopropanol-water ternary azeotrope is 88% isopropyl ether, 7.3% isopropanol and 4.7% water. Thirty grams of the isopropyl ether-isopropanol-water azeotrope and 30 grams of diethylene glycol methyl ether were charged to an Othmer type glass vapor-liquid equilibrium still and refluxed for 11 hours. Analysis of the vapor and liquid by gas chromatography gave vapor 97.3%, isopropyl ether, 2.7% isopropanol; liquid of 93% isopropyl ether, 7% isopropanol. This indicates a relative volatility of 2.72. Ten grams of the azeotrope were added and refluxing continued for another nine hours. Analysis indicated a vapor composition of 97.6% isopropyl ether, 2.4% isopropanol, a liquid composition of 94.8% isopropyl ether, 5.2% isopropanol which is a relative volatility of 2.17. The lower concentration of extractive agent gives a lower relative volatility as expected.
Example 2: Thirty grams of the isopropyl ether-isopropanol-water azeotrope, 15 grams of propylene glycol methyl ether and 15 grams of diethylene glycol diethyl ether were charged to the vapor-liquid equilibrium still and refluxed for six hours. Analysis indicated a vapor composition of 97.6% isopropyl ether, 2.4% isopropanol, a liquid composition of 96.7% isopropyl ether, 3.3% isopropanol which is a relative volatility of 1.41. Ten grams of the azeotrope were added and refluxing continued for another six hours. Analysis indicated a vapor composition of 97% isopropyl ether, 3% isopropanol, a liquid composition of 95.2% isopropyl ether, 4.8% isopropanol which is a relative volatility of 1.62.
Example 3: A glass perforated plate rectification column was calibrated with ethylbenzene and p-xylene which possesses a relative volatility of 1.06 and found to have 4.5 theoretical plates. A solution of 50 grams of isopropyl ether, 425 grams of isopropanol and 25 grams of water was placed in the stillpot and heated. When refluxing began, an extractive agent containing pure ethylene glycol was pumped into the column at a rate of 20 ml/min. The temperature of the extractive agent as it entered the column was 58° C. After establishing the feed rate of the extractive agent, the heat input to the isopropyl ether, isopropanol and water in the stillpot was adjusted to give a total reflux rate of 10-20 ml/min. After one hour of operation, overhead and bottoms samples of approximately two ml. were collected and analysed using gas chromatography. The ratio of isopropyl ether to isopropanol in the overhead was 97.98%. The ratio of isopropyl ether to isopropanol in the bottoms was 3.59%. Using these ratios in the Fenske equation, with the number of theoretical plates in the column being 4.5, gave an average relative volatility of 4.92. After 1.5 hours of operation, the overhead and bottoms samples were taken and analysed. The ratio of isopropyl ether to isopropanol in the overhead was 98.03%. the ratio of isopropyl ether to isopropanol in the bottoms was 2.94%. This gave an average relative volatility of 5.18. After two hours of total operating time, the overhead and bottoms samples were again taken and analysed. The ratio of isopropyl ether to isopropanol in the overhead was 97.9%, the ratio of isopropyl ether to isopropanol in the bottoms was 4.84%. This gave an average relative volatility of 4.55.
We have shown that by the use of the proper compound or combination of compounds as agents, isopropyl ether can be effectively removed from its mixture with isopropanol and water in any proportion including the minimum ternary azeotrope. | Isopropyl ether cannot be completely removed from isopropyl ether--isopropanol--water mixtures by distillation because of the presence of the minimum ternary azeotrope. Isopropyl ether can be readily removed from mixtures containing it, isopropanol and water by using extractive distillation in which the extractive distillation agent is a higher boiling glycol, glycol ether or a mixture of them. Typical examples of effective agents are ethylene glycol, propylene glycol, diethylene glycol diethyl ether plus propylene glycol ethyl ether. | 2 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor memory device and, more particularly, to a sense amplifier output control circuit.
[0003] 2. Description of the Prior Art
[0004] [0004]FIG. 1 is a schematic diagram of a conventional sense amplifier and sense amplifier output control circuit. The sense amplifier 11 compares an input signal IN with a reference signal REF and generates a sense-amplifier-output (SAOUT) signal in response to a sense-amplifier-enable-bar (SAENb) signal. A first NMOS transistor N 11 transfers the SAOUT signal to a latch circuit 12 in response to a latch-enable (LATCHEN) signal. The latch circuit 12 comprises three inverters I 11 , I 12 and I 13 . The SAOUT signal, transferred to the latch circuit 12 through the first NMOS transistor N 11 , is delayed by the first inverter I 11 and the second inverter I 12 for a predetermined time. The delayed SAOUT signal is inverted by the third inverter I 13 . The output signal from the latch circuit 12 is transferred to the output terminal OUT through a second NMOS transistor N 12 driven by an output-enable (OUTEN) signal. The OUTEN signal is inverted by a fourth inverter I 14 and is inputted to a third NMOS transistor N 13 coupling the output terminal OUT and a ground voltage potential Vss, in order to control the potential of the output terminal OUT.
[0005] The conventional driving method of the sense amplifier output control circuit is described in conjunction with FIGS. 2A to 2 C showing the output waveforms of the signals identified above.
[0006] The LATCHEN signal is generated in expectation of the output time of the SAOUT signal. The first NMOS transistor N 11 is driven by the LATCHEN signal, and the SAOUT signal is stored in the latch circuit 12 . Then, the second NMOS transistor N 12 is driven by the OUTEN signal and signals are transferred from the latch circuit 12 to the output terminal OUT. If the level of the OUTEN signal is low, the OUTEN signal is inverted to the high level through the fourth inverter I 14 and the third NMOS transistor N 13 is turned on by the inverted OUTEN signal in order to fix the output terminal OUT to the low level.
[0007] It is important to set the time for latching the SAOUT signal during the above-mentioned operation. As shown in FIG. 2A, it is possible to obtain normal data at the output terminal OUT, if the levels of the LATCHEN signal and the OUTEN signal are high, and the SAOUT signal is outputted correctly. However, as shown in FIG. 2B, if the SAOUT signal is generated earlier than the LATCHEN signal, then the signals are outputted to the output terminal OUT only when the supply of the LATCHEN signal is ended and the high level OUTEN signal is supplied.
[0008] Further, as shown in FIG. 2C, if the SAOUT signal is outputted after the generation of the LATCHEN signal, then the wrong SAOUT signal corresponding to the high level LATCEN signal is outputted to the output terminal OUT.
[0009] As mentioned above, the data output speed depends on the generation time of the LATCHEN signal, and the wrong data may be outputted to the output terminal OUT, if the LATCHEN signal is generated earlier than the SAOUT signal. In order to solve this problem, the SAOUT signal is directly transferred to data output terminal OUT without passing the latch circuit 12 . However, in this case, if the SAOUT signal is changed in an instant by noise, the output data may be delayed by tens of nano-seconds even though the correct data is outputted again a little later, because time is needed to drive a large output driver transistor. That is, the prior art has the disadvantage of possible glitches caused by noise.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide a sense amplifier output control circuit capable of outputting data from the sense amplifier without unwanted delays.
[0011] It is another object of the present invention to provide a sense amplifier output control circuit with reduced malfunction and power supply requirement.
[0012] In accordance with one aspect of the present invention, there is provided a sense amplifier output control circuit comprising a first logical operating means receiving an inverted output of the sense amplifier and a first control signal; a flip-flop means including a second logical operating means and a third logical operating means, wherein the second logical operating means receives signals from the first logical operating means and the third logical operating means, and wherein the third logical operating means receives signals from the second logical operating means and the first control signal; a fourth logical operating means receiving a signal from the flip-flop means and a second control signal; and a fifth logical operating means for inverting a signal from the fourth logical operating means, wherein an output terminal of the fifth logical operating means is connected to an input terminal of the sense amplifier.
[0013] In accordance with another aspect of the present invention, there is provided a semiconductor memory device, comprising a memory cell; a sense amplifier receiving a signal from the memory cell; a first logical operating means for inverting a signal from the sense amplifier; a second logical operating means for non-disjunction of a signal from the first logical operating means and a first control signal; a flip-flop means receiving a signal from the second logical operating means and the first control signal; a third logical operating means for non-disjunction of a signal from the flip-flop means and a second control signal; and a fourth logical operating means for inverting a signal from the third logical operating means, wherein an output terminal of the fourth logical operating means is connected to an input terminal of the sense amplifier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other objects and features of the present invention will become apparent from the following description of the preferred embodiments given in conjunction with the accompanying drawings, in which:
[0015] [0015]FIG. 1 is a schematic diagram of a conventional sense amplifier and sense amplifier output control circuit;
[0016] [0016]FIGS. 2A to 2 C are graphs illustrating the output waveforms of the signals generated by the conventional sense amplifier output control circuit;
[0017] [0017]FIG. 3 is a schematic diagram of a sense amplifier and a sense amplifier output control circuit in accordance with the present invention; and
[0018] [0018]FIGS. 4A to 4 D are graphs illustrating the output waveforms of the signals generated by the sense amplifier output control circuit of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The sense amplifier output control circuit according to the present invention is formed to monitor the output of the sense amplifier and to output high level data, at the moment of changing the output signal of the sense amplifier from a low level to a high level, and to ignore the output of the sense amplifier after the moment of changing. The sense amplifier output control circuit according to the present invention is also formed to output a low level of data output signal continuously if the sense-amplifier-output-signal remains at a low level. A high level output-enable-signal is inputted to the sense amplifier for stopping the operation of the sense amplifier at the moment of changing the output signal of the sense amplifier from a low level to a high level.
[0020] Hereinafter, the sense amplifier output control circuit according to the present invention will be described in detail referring to the accompanying drawings.
[0021] [0021]FIG. 3 is a schematic diagram of the sense amplifier output control circuit according to the present invention.
[0022] A sense amplifier 21 is coupled to a sense-amplifier-output-control-circuit 30 through a first inverter I 21 . The sense-amplifier-output-control-circuit 30 comprises a first NOR gate 22 , a flip-flop circuit including a second NOR gate 23 and a third NOR gate 24 , a fourth NOR gate 25 and a second inverter I 22 . The first NOR gate 22 receives a signal from the first inverter I 21 and a monitoring-bar-signal MONb, i.e., a first control signal. The second NOR gate 23 receives signals from the first inverter I 21 and the third NOR gate 24 and outputs a data-output-bar-signal OUT 2 . The third NOR gate 24 receives a signal from the second NOR gate 23 and from the monitoring-bar-signal MONb and outputs a data-output-signal OUT 1 . The fourth NOR gate 25 receives a signal from the third NOR gate 24 and a sense-amplifier-enable-signal SAENb, i.e., a second control signal. The second inverter I 22 generates an output-enable-bar-signal OUTENb, which is inputted to the sense amplifier.
[0023] The sense amplifier 21 compares an input signal IN with a reference signal REF and generates the sense-amplifier-output-signal SAOUT, and the operation thereof is stopped in response to an output-enable-bar-signal OUTENb.
[0024] The first inverter I 21 is connected to the sense amplifier 21 and receives and inverts the sense-amplifier-output-signal SAOUT. The first NOR gate 22 receives a signal from the first inverter I 21 and the monitoring bar signal MONb.
[0025] The driving method of the sense amplifier output control circuit according to the present invention is now described in detail.
[0026] First, it is assumed that the high level monitoring-bar-signal MONb and the low level sense-amplifier-output-signal SAOUT are applied to the sense amplifier output control circuit 30 in the following description. The low level sense-amplifier-output-signal SAOUT is inverted by the first inverter I 21 . The first NOR gate 22 receives the inverted sense-amplifier-output-signal SAOUT from the first inverter I 21 and the high level monitoring-bar-signal MONb and outputs a low level signal.
[0027] The low level signal outputted by the first NOR gate 22 is inverted by the second NOR gate 23 , and a high level data-output-bar-signal OUT 2 is generated by the second NOR gate 23 . The third NOR gate 24 receives the high level data-output-bar signal OUT 2 and the monitoring-bar signal MONb and outputs a low level data-output-signal OUT 1 . The low level data-output-signal OUT 1 is inputted to the second NOR gate 23 and the fourth NOR gate 25 . The fourth NOR gate 25 receives the low level data-output-signal OUT 1 and the sense-amplifier-enable-bar signal SAENb and outputs a signal of high level. The second inverter I 22 receives and inverts the signal of high level from the fourth NOR gate 25 to generate the low level output-enable-signal OUTENb. The sense amplifier 21 is operated by the low level output-enable-signal OUTENb.
[0028] Second, it is assumed that the high level monitoring-bar-signal MONb and the high level sense-amplifier-output-signal SAOUT are applied to the sense amplifier output control circuit 30 , in the following description. The high level sense-amplifier-output-signal SAOUT is inverted by the first inverter I 21 . The first NOR gate 22 receives the low level sense-amplifier-output-signal SAOUT from the first inverter I 21 and the high level monitoring-bar-signal MONb and outputs a low level signal. The low level signal outputted from the first NOR gate 22 is inverted by the second NOR gate 23 , and a high level data-output-bar-signal OUT 2 is generated by the second NOR gate 23 . The third NOR gate 24 receives the high level data-output-bar-signal OUT 2 and the high level monitoring-bar-signal MONb and outputs the low level data-output-signal OUT 1 . The low level data-output-signal OUT 1 is inputted to the second NOR gate 23 and to the fourth NOR gate 25 . The fourth NOR gate 25 , receiving the low level data-output-signal OUT 1 and the sense-amplifier-enable-bar-signal SAENb, outputs a high level signal. The second inverter I 22 receives and inverts the high level signal from the fourth NOR gate 25 to generate the low level output-enable-signal OUTENb. The sense amplifier 21 is operated by the low level output-enable-signal OUTENb.
[0029] Third, it is assumed that the low level monitoring-bar-signal MONb and the low level sense-amplifier-output-signal SAOUT are applied to the sense amplifier output control circuit 30 in the following description. The low level sense-amplifier-output-signal SAOUT is inverted to high level by the first inverter I 21 . The first NOR gate 22 receives the high level sense-amplifier-output-signal SAOUT from the first inverter I 21 and the low level monitoring bar signal MONb and outputs a signal of low level. The low level signal outputted by the first NOR gate 22 is inverted by the second NOR gate 23 , and the high level data-output-bar-signal OUT 2 is generated by the second NOR gate 23 . The third NOR gate 24 receives the high level data-output-bar-signal OUT 2 and the low level monitoring-bar-signal MONb and outputs the low level data-output-signal OUT 1 . The low level data-output-signal OUT 1 is inputted to the second NOR gate 23 and to the fourth NOR gate 25 . The fourth NOR gate 25 , receiving the low level data-output-signal OUT 1 and the low level sense-amplifier-enable-bar signal SAENb, outputs a high level signal. The second inverter I 22 receives and inverts the high level signal from the fourth NOR gate 25 to generate a low level output-enable-signal OUTENb. The sense amplifier 21 is operated by the low level output-enable-signal OUTENb.
[0030] Fourth, it is assumed that the low level monitoring-bar-signal MONb and the high level sense-amplifier-output-signal SAOUT are applied to the sense amplifier output control circuit 30 in the following description. The high level sense-amplifier-output-signal SAOUT is inverted to the low level by the first inverter I 21 . The first NOR gate 22 receives the low level sense-amplifier-output-signal SAOUT from the first inverter I 21 and the low level monitoring bar signal MONb and outputs a high level signal. The high level signal outputted by the first NOR gate 22 is inverted by the second NOR gate 23 , and the low level data-output-bar-signal OUT 2 is generated by the second NOR gate 23 . The third NOR gate 24 receives the low level data-output-bar-signal OUT 2 and the low level monitoring-bar-signal MONb and outputs the high level data-output-signal OUT 1 . The high level data-output-signal OUT 1 is inputted to the second NOR gate 23 and to the fourth NOR gate 25 . The fourth NOR gate 25 , receiving the high level data-output-signal OUT 1 and the low level sense-amplifier-enable-bar signal SAENb, outputs a low level signal. The second inverter I 22 receives and inverts the low level signal from the fourth NOR gate 25 to generate a high level output-enable-signal OUTENb. The sense amplifier 21 is stopped by the high level output-enable-signal OUTENb.
[0031] As mentioned above, when the high level monitoring-bar-signal MONb is applied to the first inverter I 12 receiving the inverted sense-amplifier-output-signal SAOUT, the low level data-output-signal OUT 1 is generated independently of the level of the sense-amplifier-output-signal SAOUT. If the low level monitoring-bar-signal MONb is applied to the first inverter I 12 receiving the inverted sense-amplifier-output-signal SAOUT, the low level data-output-signal OUT 1 is generated if the sense-amplifier-output-signal SAOUT is at the low level. If the sense amplifier 21 outputs the high level sense-amplifier-output-signal SAOUT and the low level monitoring-bar-signal MONb is applied to the first NOR gate 22 receiving the inverted sense-amplifier-output-signal SAOUT from the first inverter I 21 , then the high level data-output-signal OUT 1 is outputted and the high level output-enable-bar-signal OUTENb is also outputted to stop the operation of the sense amplifier 21 . Accordingly, it is possible to prevent unnecessary operation of the sense amplifier and to reduce the power consumption.
[0032] [0032]FIGS. 4A to 4 D are graphs illustrating the output waveforms of the signals mentioned above.
[0033] [0033]FIG. 4A shows the output waveforms of normal condition. The sense amplifier 21 is operated in response to the low level sense-amplifier-enable-signal SAENb, and the sense-amplifier-output-signal SAOUT is outputted from the sense amplifier 21 a little later. The level of the sense-amplifier-output-signal SAOUT becomes high shortly after applying the low level monitoring-bar-signal MONb. The high level data-output-signal OUT 1 is generated by the sense-amplifier-output-control-circuit 30 and the high level output-enable-bar-signal OUTENb is also generated by the sense-amplifier-output-control-circuit 30 in order to stop the operation of the sense amplifier 21 .
[0034] [0034]FIG. 4B shows the output waveforms in the case of generating a glitch, even though the sense-amplifier-output-signal SAOUT is inverted to the high level while the low level monitoring-bar-signal MONb is applied. The high level data-output-signal OUT 1 is generated at the moment that the sense-amplifier-output-signal SAOUT is inverted. After that, the signals from the sense amplifier 21 are ignored and the output-enable-bar-signal OUTENb is generated to stop the operation of the sense amplifier 21 .
[0035] [0035]FIG. 4C shows the output waveforms in case that the level of the sense-amplifier-output-signal SAOUT becomes high level before applying the low level monitoring-bar-signal MONb, i.e., before the monitoring period. The sense-amplifier-output-signal SAOUT is outputted as data-output-signal OUT 1 and the high level output-enable-bar-signal OUTENb is outputted to stop the operation of the sense amplifier 21 , at the moment that a low level monitoring-bar-signal MONb and a high level sense-amplifier-output-signal SAOUT are applied.
[0036] [0036]FIG. 4D shows the output waveforms in case that the level of the sense-amplifier-output-signal SAOUT remains continuously at the high level for the monitoring period and the level of the real output-data-signal OUT 1 is low. In this case, the effective data-output-signal OUT 1 remains continuously at the low level as determined initial state, the output-enable-bar-signal OUTENb is the same as the sense-amplifier-enable-bar-signal SAENb.
[0037] Therefore, the data output speed may be increased by using the sense-amplifier-output-control-circuit of the present invention, as compared with that of the conventional semiconductor memory device adopting the latch circuit. Further, the interruption caused by the noise may be reduced by maintaining the state of the sense-amplifier-output-signal to high level. It is possible to reduce power consumption by stopping the operation of the sense amplifier at the moment of changing the state of the data-output-signal from low to high level.
[0038] While the present invention has been described with respect to the particular embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims. | A sense amplifier output control circuit capable of outputting data from the sense amplifier without delaying. The sense amplifier output control circuit includes a first logical operating element receiving an inverted output of the sense amplifier and a first controlling signal; a flip-flop circuit including a second logical operating element and a third logical operating element, the second logical operating element receiving signals from the first logical operating element and the third logical operating element, and the third logical operating element receives a signal from the second logical operating element and the first controlling signal; a fourth logical operating element receiving a signal from the flip-flop circuit and a second control signal; and a fifth logical operating element for inverting a signal from the fourth logical operating element. An output terminal of the fifth logical operating element is connected to an input terminal of the sense amplifier. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation-in-Part of U.S. application Ser. No. 12/955,030, filed Nov. 29, 2010 now U.S. Pat. No. 8,508,140, which claims benefit of U.S. Provisional Patent Application No. 61/373,058, filed Aug. 12, 2010, the entirety of each of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
The present invention relates to switching circuitry used in driving LED light sources. In particular, circuitry in which LEDs are driven by a regulated current source.
Conventionally, LEDs may be driven by a current source that regulates the current flowing through the LEDs and hence maintains the light output of the LEDs. FIG. 1 shows a typical circuit for driving an LED circuit in which V is an input voltage source, D is representative of a string of LEDs and G is a current source. In such a circuit, in order for current to flow through D, the source input voltage of V must be higher than the forward voltage of the LEDs D.
However, if voltage of input voltage source V is much higher than the forward voltage of D, a large voltage drop is present in current source G. Such an occurrence may cause a significant power loss in current source G, particularly if current source G is a linear current source.
BRIEF SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, an LED array switching apparatus comprises: a plurality of LED arrays arranged in a serial path, each LED array having a forward voltage; a voltage supply coupled to the plurality of LED arrays; a plurality of current sources selectively coupled to the LED arrays, each of the current sources being switchable between a current regulating state and an open state; and a controller that outputs at least one control signal generated based on at least one of: (a) at least one comparison between the voltage of the voltage supply and at least one reference voltage, and (b) currents through one or more of the current sources, the control signals controlling the turning on and off of at least one switch and a current source associated with the at least one switch. The controller, the at least one switch and current sources cooperate together such that: when the voltage of the voltage source is below the at least one reference voltage, and/or when a predetermined level of current passes through the one or more current sources, at least one switch is closed and one or more associated current sources are controlled so as to break the serial path into one or more parallel paths each including less than all of the LED arrays.
In another aspect, for at least a portion of time during which the voltage of the voltage supply is below at least one reference voltage, the one or more parallel paths comprise a plurality of parallel paths each including at least one of the LED arrays, the plurality of parallel paths supplying current to all of the LED arrays.
In another aspect, the LED array switching apparatus further comprises: at least one diode arranged in the serial path of the LED arrays intermediate between a first group of LED arrays and a second group of LED arrays; and a switchable parallel current path that connects the voltage supply to a point in the serial path between the diode and the second group of LED arrays, the at least one diode preventing current from the parallel current path from flowing in the direction of the first group of LED arrays.
In another aspect, the number of LED arrays in the first group of LED arrays is equal to the number of LED arrays in the second group of LED arrays.
In another aspect, a plurality of parallel paths supplies current to all of the LED arrays when the voltage of the voltage source is higher than the forward voltage of both of the first or second group of LED arrays, but is less than the at least one reference voltage.
In another aspect, the voltage source is a rectified AC voltage, and the switching apparatus further comprises: valley-fill circuitry configured to prevent occurrence of any off period of light output at a zero crossing portion of the AC voltage.
In another aspect, the valley-fill circuitry includes at least one energy storage capacitor that discharges when the rectified AC voltage drops below half its peak value to prevent any off period of the light output.
In another aspect, at least one of the plurality of LED arrays comprises a plurality of LEDs.
In another aspect, the plurality of LEDs forming the at least one of the plurality of LED arrays are arranged in parallel.
In another aspect, the controller comprises one or more voltage comparators.
In another aspect, the controller comprises a microcontroller.
In another aspect, the microcontroller is configured to detect a fault in an LED array and modify a switching sequence to exclude the faulted LED array.
In another aspect, the at least one reference voltage is a plurality of reference voltages, and the at least one switch is a plurality of switches, and each of the plurality of reference voltages corresponds with a respective one of the switches.
In accordance with a second aspect of the present invention, an LED array switching apparatus comprises: a plurality of LED arrays arranged in a serial path, each LED array having a forward voltage; a voltage supply coupled to the plurality of LED arrays; a voltage comparator that compares the voltage of the voltage supply with a reference voltage and controls a switch to turn off when the voltage of the voltage supply is greater than or equal to the reference voltage; and a plurality of current sources selectively coupled to the LED arrays each of the current sources is switchable between a current regulating state and an open state. The voltage comparator, the switch and current sources cooperate together such that: (a) when the voltage of the voltage source is below the reference voltage, the switch is closed and the current sources are controlled so as to break the serial path into one or more parallel paths each including less than all of the LED arrays, and (b) when the voltage of the voltage supply is greater than or equal to the reference voltage, as the voltage of the voltage supply increases, LED arrays are switched on and lit to form a higher forward voltage LED string, and as the voltage of the voltage supply decreases, LED arrays are switched off and removed from the LED string starting with the most recently lit array.
In another aspect, for at least a portion of time during which the voltage of the voltage supply is below the reference voltage, the one or more parallel paths comprise a plurality of parallel paths each including at least one of the LED arrays, the plurality of parallel paths supplying current to all of the LED arrays.
In another aspect, the LED array switching apparatus further comprises: a diode arranged in the series path of the LED arrays intermediate between a first group of LED arrays and a second group of LED arrays; and a switchable parallel current path that connects the voltage supply to a point in the series path between the diode and the second group of LED arrays, the diode preventing current from the parallel current path from flowing in the direction of the first group of LED arrays.
In another aspect, the number of LED arrays in the first group of LED arrays is equal to the number of LED arrays in the second group of LED arrays.
In another aspect, a plurality of parallel paths supplies current to all of the LED arrays when the voltage of the voltage source is higher than the forward voltage of both of the first or second group of LED arrays, but is less than the reference voltage.
In another aspect, the voltage source is a rectified AC voltage, and the switching apparatus further comprises: valley-fill circuitry configured to prevent occurrence of any off period of light output at a zero crossing portion of the AC voltage.
In another aspect, the valley-fill circuitry includes at least one energy storage capacitor that discharges when the rectified AC voltage drops below half its peak value to prevent any off period of the light output.
In another aspect, the sum of the forward voltages of LED arrays in the first group of LED arrays is approximately equal to sum of the forward voltages of the LED arrays in the second group of LED arrays.
In another aspect, at least one of the plurality of LED arrays comprises a plurality of LEDs.
In another aspect, the plurality of LEDs forming the at least one of the plurality of LED arrays are arranged in parallel.
BRIEF DESCRIPTION OF THE DRAWINGS
The figures are for illustration purposes only and are not necessarily drawn to scale. The invention itself, however, may best be understood by reference to the detailed description which follows when taken in conjunction with the accompanying drawings in which:
FIG. 1 is a circuit diagram of a conventional LED driving circuit that utilizes a current source;
FIG. 2 is functional block diagram of a circuit for LED array switching in accordance with an embodiment of the present invention;
FIGS. 3A-3F are diagrams illustrating current paths taken through the circuit of FIG. 2 at different voltages levels of the source voltage, in accordance with an embodiment of the present invention.
FIG. 4 is a functional block diagram of the circuit of FIG. 2 with an optional set of current sources for averaging of the usage among the LEDs, in accordance with an aspect of the present invention.
FIG. 5 is a circuit diagram showing a practical implementation of the circuit shown in FIG. 2 .
FIG. 6 is a diagram of the voltage waveform across nodes A and B in FIG. 5 .
FIG. 7 is a diagram of the current through element M 1 in FIG. 5 .
FIG. 8 is a diagram of the current through element M 2 in FIG. 5 .
FIG. 9 is a diagram of the current through element M 3 in FIG. 5 .
FIG. 10 is a diagram of the current through element DX 1 in FIG. 5 .
FIG. 11 is a diagram of the current through element DX 3 in FIG. 5 .
FIG. 12 is a diagram of the current through element DX 4 in FIG. 5 .
FIG. 13 is a diagram of the light output waveform of the circuit in FIG. 5 .
FIG. 14 is a diagram showing the input waveform at the AC main source in FIG. 5 .
FIG. 15 is a circuit of a bleeder circuit that can be used with the circuit of FIG. 5 .
FIG. 16 is functional block diagram of a circuit for LED array switching in accordance with a second embodiment of the present invention.
FIG. 17 is functional block diagram showing how a microcontroller can be used with the circuit of FIG. 16 .
FIG. 18 is functional block diagram of an example circuit for LED array switching in accordance with the second embodiment of the present invention.
FIGS. 19A-19G are diagrams illustrating current paths taken through the circuit of FIG. 18 at different voltages levels of the source voltage, in accordance with the second embodiment of the present invention.
FIG. 20 is a circuit diagram showing a practical implementation of the circuit shown in FIG. 18 .
FIG. 21 is a diagram of the rectified mains voltage in FIG. 20 .
FIG. 22 is a diagram that shows the LED arrays that are conducting during a half AC cycle.
FIG. 23 is a diagram of the current through element D 1 in FIG. 20 .
FIG. 24 is a diagram of the current through element D 2 in FIG. 20 .
FIG. 25 is a diagram of the current through element D 3 in FIG. 20 .
FIG. 26 is a diagram of the light output waveform of the circuit in FIG. 20 .
FIG. 27 is a diagram of the current of the AC mains source.
FIG. 28 is a diagram of an exemplary valley-fill passive power factor correction circuit.
FIG. 29 is a diagram of the mains voltage waveform with the valley-fill circuit.
FIG. 30 is a diagram of the current through element D 1 with the valley-fill circuit.
FIG. 31 is a diagram of the current through element D 2 with the valley-fill circuit.
FIG. 32 is a diagram of the current through element D 3 with the valley-fill circuit.
FIG. 33 is a diagram of the light output waveform of the circuit with the valley-fill circuit.
FIG. 34 is a current waveform of the AC mains source with the valley-fill circuit.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 2-34 illustrate aspects of preferred embodiments of LED array switching apparatus. For an LED lighting device to work using a varying input voltage source, such as a rectified AC source, the switching apparatus in accordance with the first embodiment of the present invention divides the LED string into a series of multiple arrays. When the input voltage is low, only the first LED array is lit up. As the input voltage increases, subsequent LED arrays are switched in series to form a higher forward voltage string. Contrarily, if the input voltage decreases, the sequence is reversed and arrays are removed from the string starting with the last light-up array.
FIG. 2 shows the functional blocks of proposed circuitry. It is assumed that the LED string is divided into n LED arrays or arrays D 1 to Dn, where n>1. Each LED array may consist of one or more LEDs arranged in any know manner, i.e., in sequence or in parallel, or combinations thereof G 1 to Gn are current sources which can be disabled, that is, changed to an open circuit condition, by current sense signals from successive current sources.
The operation of the circuit of FIG. 2 is next described making reference to FIGS. 3A-3F , for the case in which the voltage of V 1 is ramping up from zero. When the voltage of V 1 is just above the forward voltage of LED array D 1 , current begins to flow through LED array D 1 and current source G 1 , as shown in FIG. 3A . Current source G 1 regulates the current through LED array D 1 as voltage of V 1 is further increased. LED array D 2 begins to conduct when V 1 reaches the sum of the forward voltages of LED array D 1 and LED array D 2 , as shown in FIG. 3B . As the current through LED array D 2 is increasing to a threshold value, which is preferably set lower than the regulating value of current source G 2 , current source G 1 is disabled, becoming an open circuit. The current through LED array D 1 and LED array D 2 is then regulated by current source G 2 , as shown in FIG. 3C .
FIG. 3D shows the current path in the circuit when V 1 has been increased to the point at which current source Gn−1 regulates the current through LED arrays D 1 to Dn−1. Further increasing V 1 causes LED array Dn to conduct, as shown in FIG. 3E . FIG. 3F shows the current path when the current through LED array Dn is increased to trigger current sources G 1 to Gn−1 to be in the open condition.
As would be understood by one of ordinary skill in the art, the switching sequence shown in FIGS. 3A-3F would be reversed if the voltage of V 1 is declining. In particular, the situation in which the voltage of V 1 is high enough to pass a regulated current through LED arrays D 1 to Dn and current source Gn is shown in FIG. 3F . As V 1 is decreased, the current through Gn starts to decrease and to a point below the threshold value, current source Gn−1 is enabled and current begins to flow through current source Gn−1 as shown in FIG. 3E . When V 1 decreases to a value below the sum of forward voltage sum of LED arrays D 1 to Dn, current through LED array Dn is stopped, as shown in FIG. 3D .
As can be seen from the foregoing description, in the circuit of FIG. 2 , LED array D 1 conducts if any one of the current sources is conducting. On the other hand, LED array Dn only conducts if current source Gn is conducting. Thus, in operation, LED array D 1 would be used more often than LED array Dn. FIG. 4 is a block diagram of a circuit that averages the usage among LED arrays D 1 to Dn. The circuit includes a set of additional current sources GT 1 -GTn and a current source set toggle switcher TS 1 added to the circuit of FIG. 2 .
As can be seen in FIG. 4 , the current source set toggle switcher TS 1 has two complementary signal outputs Q and Q . Preferably, the toggle switcher TS 1 is configured such that these outputs are toggling at frequency above 20 Hz, to avoid the perception of flicker. When Q of the toggle switcher TS 1 is active, the switch ST 1 connected to this output becomes closed, current sources GT 1 to GTn are disabled, and switch S 1 is opened. In this condition, the circuit of FIG. 4 is essentially identical to the circuit shown in FIG. 2 , and operates as described above upon occurrence of ramping up or down of input voltage V 1 .
When Q becomes active, and Q becomes non-active, switch S 1 becomes closed, current sources G 1 to Gn are disabled, switch ST 1 is opened, and current sources GT 1 to GTn are operational. In this situation, if V 1 is ramping up from zero voltage, unlike in the circuit of FIG. 1 , Dn will be the first conducting array followed by Dn−1, just the opposite of what occurs in the circuit of FIG. 2 . Thus, over time, the usage of the LEDs will average out.
FIG. 5 shows a practical detailed implementation of the proposed circuit shown in FIG. 2 with n=3. In the figure, the AC 220V main voltage source is a rectified signal. The voltage waveform across node A and B is shown in FIG. 6 . The LED string, consists of four LEDs DX 1 -DX 4 , with forward voltage of 50V each, and is divided into 3 arrays. The first array has 2 LEDs (DX 1 and DX 2 ) while the second and third arrays, each have a single LED (DX 3 and DX 4 , respectively).
As can be seen in the figure, transistor M 1 , resistors R 1 and R 11 , transistor Q 1 and diode D 1 form a current source that drives LEDs DX 1 and DX 2 . Transistor Q 11 turns off transistor M 1 when the current through transistor M 2 reaches threshold value.
FIG. 7 shows the current waveform of transistor M 1 . Waveforms corresponding to the current in transistors M 2 and M 3 are shown in FIGS. 8 and 9 , respectively. FIGS. 10 , 11 and 12 show the current waveforms of LEDs DX 1 , DX 3 and DX 4 respectively. The current of LED DX 1 is the current sum of transistors M 1 , M 2 and M 3 , while the current of LED DX 3 is the current sum of transistors M 2 and M 3 . FIG. 13 shows the light output waveform of all the LED arrays.
FIG. 14 shows the input current waveform from AC main power source. Throughout most of the half line cycle, the current is continuous, which makes the circuit suitable to work with an optional triac dimmer, shown in FIG. 5 . An optional bleeder circuit can be added to provide a current path for the triac dimmer's RC timing circuit when the triac is off. FIG. 15 shows a form of bleeder circuit which connects to node A and B of FIG. 5 . The bleeder circuit acts like a resistive load for the dimmer when the triac is not conducting. A bypass resistor 110 is switched on by transistor 2 N 60 to connect across the rectified input voltage when the rectified input voltage is low (which indicates the triac is off). With the bypass resistor completing the circuit, sufficient charging current can be supplied to the internal RC timing circuit of the triac dimmer to ensure proper operation. When the rectified input voltage is high (which indicates the triac is on), the bypass resistor is disconnected by transistor 2 N 60 to minimize wasteful power dissipation.
In the first embodiment at low levels of input voltage, only the first and second arrays D 1 and D 2 conduct. This condition results in a lowered light output current waveform during low levels of input voltage, as can be seen in FIG. 13 discussed above. A second embodiment of an LED switching apparatus is described with reference to FIGS. 16-34 . The second embodiment provides a time period at low input voltage in which all of the LED arrays conduct current, in parallel branches, which alleviates the abovementioned problem shown in FIG. 13 . FIG. 16 shows the functional blocks of a circuit for LED switching in accordance with the second embodiment.
In the circuit shown in FIG. 16 , V 1 is a varying DC voltage source. D 1 to Dn are LED arrays, each of which can be more than one LED, formed in series or parallel or combinations of serial and parallel. G 1 to Gn are current sources. S 1 to Sn are switches. Db 1 to Dbn are diodes. Each single diode Dbi, where i can be 1 to n, functions to prevent current through switch Si to current source Gi when switch Si is switched on. Control signal CSi is used to select either conducting state or open circuit state of both switch Si and current source Gi.
When CS 1 to CSn are not activated, switches S 1 to Sn−1 are off and current sources G 1 to Gn−1 are in open circuit condition. All LED arrays D 1 to Dn are series connected through diodes Db 1 to Dbn and current is controlled by current source Gn. In this situation, if V 1 is lower than the total forward voltage of D 1 to Dn, the LED arrays will not be lit. However, in accordance with the disclosed embodiment, this low voltage condition can be sensed, for example by a controller that can perform voltage comparison, and the controller can then preferably apply one or more of the control signals to break the serial path into parallel paths, each having a lower forward voltage arrangement than V 1 , allowing the LEDs in the parallel paths to be lit even when the voltage is low.
For example, when a single control signal CSi is activated, Gi is conducting and current through LED arrays D 1 to Di will be controlled by Gi. Also, switch Si is conducting and current is directly supplied from V 1 to LED arrays Di+1 to Dn. In this case, two parallel connected current paths are formed, i.e., current path from D 1 to Di which is controlled by Gi and current path from Di+1 to Dn which is controlled by Gn. If a further control signal CSj is activated, where j>i, the circuit will change into three parallel connected current paths of D 1 to Di, Di+1 to Dj, and Dj+1 to Dn which are controlled by Gi, Gj and Gn respectively.
When all control signals CS 1 to CSn are activated, all LED arrays D 1 to Dn will be parallel connected to V 1 through current sources G 1 to Gn respectively. The creation of the different parallel paths permits the LEDs to be lit even when the input voltage V 1 is low. For example, to allow for the lighting of LED arrays even at low input voltage V 1 , the activation of the control signals can be controlled such that for the lowest input voltage, the greatest number of parallel paths is formed, each path having a forward voltage that can be lit by the present input voltage. As the input voltage V 1 increases, a smaller number of parallel paths can be formed by application of control signals as described above, each path having more LED arrays, until, above a certain voltage, e.g., a voltage greater than or equal to the forward voltage of LED arrays D 1 to Dn, a single string of LED arrays D 1 to Dn is formed, which in the above example, would be when no control signals are activated.
The control signals can be generated by voltage comparators which compares the voltage of V 1 to certain threshold voltage or current sensors which sense the currents through the current sources. More sophisticated control can be implemented with the use of a microcontroller. FIG. 17 shows the functional block diagram of a microcontroller that can be used with the circuit of FIG. 16 . In FIG. 17 , V V1 and I V1 denote the voltage across V 1 and the current through V 1 respectively. V Gi and I Gi denote the voltage across Gi and the current through Gi respectively. The microcontroller preferably samples and processes the various voltage/current signals and generates control signals CS 1 to CSn according to algorithms that are designed to optimize efficiency, input power quality, LED arrays usage and light output uniformity, etc.
For example, a simple example of such an algorithm is to keep the voltage difference between V 1 and the forward voltage of combined LED arrays small in order to maximize efficiency. It is assumed the forward voltages of all LED arrays D 1 to Dn are equal to same value Vd and maximum of V 1 is higher than the forward voltage sum of D 1 to Dn, i.e. nVd. When V 1 <2Vd, all control signals are activated and D 1 to Dn are parallel connected through G 1 to Gn respectively. When 2Vd≦V 1 <3Vd, only control signals CSi are activated where i is even and i≦n. When 3Vd≦V 1 <4Vd, only control signals CSi are activated where i is multiple of 3 and i≦n. When jVd≦V 1 <(j+1)Vd, only control signals CSi are activated where i is multiple of j and i≦n. When nVd≦V 1 , all control signals are de-activated and D 1 to Dn are connected in series through current source Gn. This is only one example and the invention is not limited to this exemplary embodiment.
Also, the microcontroller can be programmed to have fault handling ability, e.g., the microcontroller can detect any faulted LED array and re-arrange the switching sequence to exclude the faulted LED array. For example, the microcontroller can be programmed so that if Di has a short circuit fault, control signal CSi−1 will be permanently de-activated so that Di−1 and Di can be considered as a single array. If Di has an open circuit fault, current will no longer flow through Di and control signal CSi will be permanently activated in order to have current supplied from V 1 to Di+1
FIG. 18 shows an example circuit of control signals generated by voltage comparator and current sensor. In the circuit, current source G 1 and switch S 1 are controlled by voltage comparator X 1 . Current source G 2 can be disabled by current sense signal from current source G 3 . A reference voltage source, Vref, is coupled to the voltage comparator X 1 . It should be noted that in this exemplary circuit D 2 and D 3 are directly connected in series without any diode in between. It is because only two parallel current branches (D 1 and D 2 +D 3 ) are needed in this example and thus there is no need for connecting a switch and a blocking diode to the anode of D 3 .
For explanation purposes, it is assumed that the forward voltage of LED array D 1 is larger than the forward voltage sum of D 2 and D 3 , however this is not required. The operation of the circuit shown in FIG. 18 is next shown for the case in which the voltage of V 1 is ramping up from zero. While the voltage of V 1 is less than the reference voltage Vref, comparator X 1 outputs an active signal which enables both current source G 1 and switch S 1 . When the voltage of voltage source V 1 is just above the forward voltage of D 2 , current begins to flow through switch S 1 , LED array D 2 and current source G 2 as shown in FIG. 19A . Current source G 2 regulates the current through LED array D 2 as voltage of V 1 is further increased.
LED array D 3 begins to conduct through current source G 3 when V 1 reaches the sum of the forward voltages of LED arrays D 2 and D 3 , as shown in FIG. 19B . As the current through LED array D 3 and current source G 3 is increasing to a threshold value, preferably lower than the regulating value of current source G 3 , current source G 2 is disabled, as shown in FIG. 19C . LED array D 1 begins to conduct through current source G 1 as V 1 gets higher to the forward voltage of D 1 , as shown in FIG. 19D .
It is preferable to set Vref to be slightly larger than the sum of forward voltages of LED arrays D 1 and D 2 . FIG. 19E shows the current path when V 1 is increased to Vref or above. In this case, switch S 1 and current source G 1 are set to an open circuit condition by voltage comparator X 1 . Current flows through LED array D 1 , diode Db 1 (which prevents back directional current), LED array D 2 and current source G 2 . Further increasing V 1 causes LED array D 3 to conduct, as shown in FIG. 19F . FIG. 19G shows the current path when the current through LED array D 3 is increased to trigger current source G 2 to be in the open condition.
As would be understood by one of skill in the art, the switching sequence shown in FIGS. 19A-19G would be reversed if the voltage of V 1 is declining. In particular, the situation in which the voltage of V 1 is high enough to pass a regulated current through LED arrays D 1 to D 3 and current source G 3 as shown in FIG. 19G . As V 1 is decreased the current through current source G 3 starts to decrease and to a point below the threshold value, current source G 2 is enabled and current begins to flow through current source G 2 , as shown in FIG. 19F . When V 1 decreases to a value below the sum of forward voltage sum of LED arrays D 1 to D 3 , current through LED array D 3 is stopped, as shown in FIG. 19E .
As V 1 is further decreased to below Vref, switch S 1 and current source G 1 are enabled to conduct. Current through LED array D 1 is regulated by current source G 1 . Current through LED arrays D 2 and D 3 is regulated by current source G 3 . Further decreasing V 1 causes current through current source G 1 to decrease to zero. When the current through current source G 3 is decreased to a point below the threshold value, current source G 2 is enabled, as shown in FIG. 19B . When V 1 is decreased to below the sum of forward voltages of LED arrays D 2 and D 3 , current can only flow through LED array D 2 and current source G 2 , as shown in FIG. 19A .
As can be seen from the above, the design of the circuit shown in FIG. 18 provides for a period of driving of all of the LED arrays, in parallel, even during the period of time that the voltage of the voltage supply is below Vref. This provides an improvement in the supply of current to the LED arrays and hence light output during low voltage operation as compared with the design of the first embodiment.
FIG. 20 shows a practical exemplary detailed implementation of the proposed circuit shown in FIG. 18 . In the figure, the AC 230V mains voltage is a rectified signal. The voltage waveform across node A and B is shown in FIG. 21 . Three LED arrays D 1 -D 3 are used. The forward voltage of LED array D 1 is 150V and forward voltage of both LED arrays D 2 and D 3 are 75V in the illustrative embodiment.
As can be seen in the figure, transistor M 1 , resistors R 1 and R 11 , and Zener diode ZD 1 form a current source (generally corresponding to current source G 1 in FIGS. 18 and 19 ) which drives LED array D 1 . Resistors R 4 , R 14 and transistor Q 4 form a voltage comparator corresponding to X 1 in FIGS. 18 and 19 . Transistor M 2 , resistors R 2 , R 12 and Zener diode ZD 2 form a current source corresponding to transistor G 2 in FIGS. 18 and 19 . Transistor M 3 , resistors R 3 , R 33 , R 13 and Zener diode ZD 3 form a current source corresponding to G 3 in FIGS. 18 and 19 .
When the rectified mains voltage is low, transistors M 1 and Q 6 are conducting such that LED array D 1 are parallel connected with LED arrays D 2 and D 3 . In the exemplary embodiment, when rectified mains voltage level is above 225VDC, transistor Q 4 turns off transistor M 1 , transistor Q 5 and in turn transistor Q 6 making a series connection of LED arrays D 1 , D 2 and D 3 . FIG. 22 is a diagram that shows the LED arrays that are conducting during a half AC cycle.
As can be seen in the diagram of FIG. 22 , and as was also illustrated in the description above relating to FIGS. 19A-19G , during the period of time that the voltage of the voltage supply is equal to or greater than the reference voltage, a forward voltage string of serially connected LED arrays is formed, which increases as the voltage of the voltage supply continues to increase above the reference voltage, and which is shortened as the voltage begins to decline. In the illustration, the forward voltage string initially includes D 1 and D 2 . As the voltage of the voltage supply approaches its peak, the forward voltage string includes D 1 -D 3 , and then, as the voltage of the voltage supply decreases, the length of the forward voltage string is reduced to D 1 and D 2 .
As also shown in the diagram, during a portion of each period in which the voltage of the voltage supply is below the reference voltage, current will flow through all of the LED arrays D 1 -D 3 , but this will occur in a parallel configuration, with one branch having LED array D 1 , and the other branch having LED arrays D 2 and D 3 , as discussed above with reference to FIGS. 19A-19G .
FIG. 23 shows the current waveform of LED array D 1 . Waveforms of LED arrays D 2 and D 3 are shown in FIGS. 24 and 25 respectively. FIG. 26 shows the light output waveform of all the LED arrays. It should be noted the off time during zero crossing of the AC mains voltage is shorter than that in FIG. 13 . The full light output time is also longer that that in FIG. 13 .
FIG. 27 shows the input current waveform from AC mains power source. The power factor for the exemplary circuit is about 0.85. Throughout most of the half line cycle, the current is continuous which makes the circuit suitable to work with triac dimmer. Efficiency of the illustrated exemplary circuit is about 84%.
An optional valley-fill passive power factor correction circuit can be added to improve the power factor and remove the off period at the zero crossing mentioned above. FIG. 28 shows an illustrative embodiment of an exemplary valley-fill circuit, which in use could be used to connect to nodes A and B of FIG. 20 . In operation, the rectified mains voltage charges the valley-fill capacitors through the path C 1 , D 5 , R 7 and C 2 . When the rectified mains voltage drops below half of its peak value, C 1 begins to discharge through D 7 and C 2 begins to discharge through D 6 .
FIG. 29 shows the rectified mains voltage waveform with the exemplary valley-fill circuit. It can be seen that the voltage does not go below 150VDC because of presence of the energy storage capacitors C 1 and C 2 in the valley-fill circuit.
FIG. 30 shows the current waveform of LED array D 1 using the valley-fill circuit. It is noted that because of the valley-fill circuit, the waveform contains no off period. FIG. 31 shows the current waveform of LED array D 2 , when the valley-fill circuit is used, which is similar to waveform of LED array D 1 . It should be noted that since the rectified voltage is always, in the exemplary circuit, above 150V (the sum of forward voltage of LED arrays D 2 and D 3 in the example), the stage shown in FIG. 19A above will never occur when using the valley-fill circuit. FIG. 32 shows the current waveform of LED array D 3 using the exemplary valley-fill circuit. FIG. 33 shows the light output waveform of all of the LED arrays. It should be noted by virtue of the valley-fill circuit, there is no off period in the light output.
FIG. 34 shows the input current waveform from AC mains power supply using the exemplary valley-fill circuit. The power factor is improved to 0.9, while the efficiency of the circuit is kept at about 84%.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof. | An LED array switching apparatus, comprises: a plurality of LED arrays arranged in a serial path; a voltage supply coupled to the plurality of LED arrays; a plurality of current sources selectively coupled to the LED arrays, each of the current sources being switchable between a current regulating state and an open state; and a controller that outputs at least one control signal. The controller, the at least one switch and current sources cooperate together such that: when the voltage of the voltage source is below the at least one reference voltage, and/or when a predetermined level of current passes through the one or more current sources, at least one switch is closed and one or more associated current sources are controlled so as to break the serial path into one or more parallel paths each including less than all of the LED arrays. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to a system for controlling a coolant temperature of an internal combustion engine, and more particularly to a closed loop system for adjusting the temperature of a coolant to a target value which varies in response to operating conditions of the engine.
In widely used automotive internal combustion engines, in order to control a coolant temperature, a thermostat valve, which is designed to be opened at a predetermined temperature, for example 80° C., is disposed in a coolant circulating circuit including a radiator. In this case, the coolant is kept at around the predetermined temperature of 80° C.
Recently, attention has been paid to a control apparatus for keeping the coolant at different temperatures by varying the valve opening temperature of the thermostat valve in response to operating conditions of an engine.
According to this control apparatus, when an engine operates with a low load where thermal load is small with the least possibility of causing the engine to overheat, the thermostat valve opening temperature is raised to elevate the coolant temperature, thereby improving fuel economy and the exhaust gas purification. When the engine operates with a high load, the thermostat valve opening temperature is lowered to drop the coolant temperature, preventing the occurrence of knocking and enhancing "volumetric efficiency," thereby increasing power output of the engine.
One control apparatus falling into the above category is disclosed in Japanese Utility Model Application Provisional Publication No. 54-142722, which will be described referring to FIG. 1.
In a coolant passage 1, a thermostat 2 is disposed. The thermostat 2 operates as follows: When the coolant temperature rises, wax contained inside the thermostat 2 is expanded, thereby pushing a piston 3 upwardly as viewed in FIG. 1. This upward movement of the piston 3 is prevented when the piston 3 abuts a receiving portion 8 of a control rod 7 of a diaphragm device 6. Thus, a further projection of the piston 3 out of the thermostat 2 causes a valve 4 to disengage from a valve seat 12 against a return spring 5. If the control rod 7 is displaced upwards as viewed in FIG. 1, the piston 3 has to project further out of the thermostat 2 until the valve 4 starts to disengage from the valve seat 12.
Therefore, when the control rod 7 is lifted by the diaphragm 9, the valve 4 will not be opened until the coolant temperature rises further and the piston 3 is extended further. This causes an increase in the temperature of the coolant.
Intake manifold vacuum is admitted to a vacuum chamber 10 of the diaphragm device 6 acting on the diaphragm 9 in such a manner as to lift the diaphragm 9 against a diaphragm spring 11.
Since the intake manifold vacuum is high during engine operation with low load and low during engine operation with high load, the control rod 7 is lifted further, as viewed in FIG. 1, during engine operation with low load.
In this manner, the temperature at which the valve 4 is opened increases during engine operation with low load, whereas this temperature decreases during engine operation with high load. This causes the coolant temperature to rise during low load operation and drop during high load operation. If it is desired to increase the coolant temperature, a diaphragm spring 11 with a large spring force must be used because it acts on the diaphragm 9 against a reaction force which is applied to the diaphragm 9 via the control rod 7 when the valve 4 is pressed downwards against the return spring 5. On the other hand, the diaphragm 9 on which intake manifold vacuum acts against the diaphragm spring 11 must have a large pressure acting area, resulting in an increase in size and weight of each of the associated component parts. Therefore, if it is desired to set the coolant temperature high, the manufacturing cost increases. Besides, the operating life is short because the component parts are subjected to engine vibrations.
Another problem is that even though it is possible to vary the coolant temperature in response to a change in engine load, it is impossible to vary the coolant temperature in response to engine speed. Thus, this known control apparatus fails to meet a demand that the coolant temperature should drop as the engine speed increases even with the same engine load.
Referring to FIGS. 2 and 3, two well known ways of installing a thermostat are described. FIG. 2 shows a so-called "outlet control" and FIG. 3 shows a so-called "inlet control".
Referring to FIG. 2, a thermostat valve 2A is disposed in an outlet passage 15 which passes a relatively hot coolant, having cooled an engine main body 13, toward a radiator 14. A bypass passage 16, i.e., a passage bypassing the radiator 14, branches off from a portion upstream of this thermostat valve 2A and is connected to an intermediate portion of an inlet passage 18 which passes therethrough a relatively cool coolant having its heat dissipated after passing through the radiator 14 toward a water jacket (not shown) of the engine main body 13 via a water pump 17.
With this control arrangement, if the valve opening temperature of the thermostat valve 2A is set high, a difference between a temperature when the thermostat 2A is opened and a temperature when the thermostat 2A is closed increases as shown in FIG. 4, increasing the occurrence of a so-called hunting phenomenon.
Referring to FIG. 3, a thermostat valve 2B is disposed in an inlet passage 18 at a position immediately upstream of a junction where a bypass passage 16 joins with the inlet passage 18. Since the thermostat valve 2B senses the temperature of coolant resulting from mixing a relatively cool coolant having its heat dissipated via a radiator 14 with a relatively hot coolant coming from the bypass passage 16, the occurrence of the hunting phenomenon as mentioned before decreases. However, with this arrangement, because suction created by a water pump 17 acts on the thermostat valve 2B in a valve opening direction, the spring constant and the spring load of a valve return spring have to be set sufficiently high in order to prevent overcooling of coolant. To meet this requirement, the thermostat valve 2B has to use a large diaphragm device.
SUMMARY OF THE INVENTION
The present invention provides a coolant temperature control system for an internal combustion engine which can adjust coolant temperature accurately to different temperatures preset for various engine operating conditions in order to enhance fuel economy, exhaust gas purification and engine operation performance and which allows the use of a compact control actuator (diaphragm device).
According to the present invention, the coolant temperature can be adjusted accurately to different target temperatures by means of a control system which comprises sensors for detecting operating condition of the engine, means for generating a target temperature for the detected operating condition, a temperature sensor for sensing an actual coolant temperature of the coolant, and means for controlling the flow rate of coolant passing through a radiator in such a manner as to decrease a difference between the actual and target coolant temperatures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a prior art coolant temperature control apparatus;
FIGS. 2 and 3 are schematic sectional views showing two examples of arranging a thermostat controlled valve in a coolant circulating circuit;
FIG. 4 shows graphs of a variation in coolant temperature vs. time along with a variation in valve lift vs. time which are obtained with the FIG. 2 control arrangement during operation at 40 km/h with raod load;
FIG. 5 is a schematic, partly sectioned, view showing a first embodiment of a system according to the present invention;
FIG. 6 is a diagram showing one example of a controller;
FIG. 7 is a graph showing one example of a table containing various target coolant temperature values;
FIG. 8 is a flowchart showing a control routine executed by the controller;
FIG. 9 shows graphs, similar to FIG. 4 of a control characteristic obtained by the system according to the present invention; and
FIG. 10 is a similar view to FIG. 5 showing a second embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 5 to 9, the first embodiment according to the present invention is described.
Referring first to FIG. 5, a flow control valve 20 is disposed in an outlet passage 15 at a position immediately downstream of a junction where a bypass passage 16 branches off from the outlet with the inlet passage 15.
The outlet passage 15 receives a relatively hot coolant having passed through an engine main body 13 and admits same to a radiator 14 where the heat is dissipated from the coolant. The relatively cool coolant from the radiator 14 is allowed to flow through an outlet passage 18 into the engine main body 13 under the action of a water pump 17. A bypass passage 16 has one end connected to the inlet passage 15 and an opposite and connected to the outlet passage 18 to bypass the radiator 14. Therefore, outlet passage 15, radiator 14, inlet passage 18, bypass passage 16, and water pump 17 define at least part of a coolant circulating circuit.
The flow control valve 20 is of a vacuum actuated type and operable in response to a vacuum regulated by a vacuum regulator 21. The flow control valve 20 includes, a valve element 23 connected to a diaphragm 25 via a rod 24 and a spring 28 biasing the valve element 23 in a valve opening direction. The valve element 23 cooperates with a seat portion 22 formed in the outlet passage 15 to open or close the outlet passage 15.
The diaphragm 25 has a righthand side thereof, as viewed in FIG. 5, exposed to the coolant discharged from the water pump 17 and a lefthand side thereof, as viewed in FIG. 5, defining a vacuum chamber 26 which communicates with the vacuum regulator 21. The spring 28 is disposed in the vacuum chamber 26 and has one end bearing on the diaphragm 25 so as to bias the valve element 23 in the valve opening direction.
The vacuum regulator 21 comprises a pressure regulating unit 30 for keeping engine intake manifold vacuum supplied thereto at a predetermined value (such as, -120 mmHg), and a solenoid unit 32 for modifying the vacuum on which the flow control valve 20 is operable in response to an electric signal supplied by a later described controller 31.
Intake manifold vacuum of the engine 13 is admitted via a tube 33 to a nozzle 33A which is closed or opened by a valve element 34A fast on a diaphragm 34 which defines a regulating chamber 35 on one side thereof and an atmospheric chamber 36 opening to the atmosphere pressure on the opposite side thereof. Springs 37 and 38 bias the diaphragm 34 in the opposite directions.
The regulating chamber 35 which has the nozzle 33A communicating with the source of intake manifold vacuum has another tube 39 provided with an orifice 40. The tube 39 is formed with a nozzle 39A cooperating with a valve element 42 actuable by a solenoid 41. From a portion of the tube 39 between the orifice 40 and the nozzle 39A, a vacuum line 43 is branched off and leads to the vacuum chamber 26 of the flow control valve 20.
The valve element 42 is fast on a diaphragm 44 and cooperates with the solenoid 41 such that when the solenoid 41 is energized, the valve element 42 opens the nozzle 39A, admitting atmospheric air into the vacuum line 43, while when it is deenergized, the valve element 42 closes the nozzle 39A due to the bias of the diaphragm 44, allowing the same vacuum as in the regulating chamber to develop in the vacuum line 43.
A temperature sensor 45 is disposed in the inlet passage 18 at a portion downstream of a junction where the branch passage 16 joins with the inlet passage 18. The sensor output of the sensor 45 is fed to the controller 31.
The controller 31 also receives output signals from an intake manifold sensor 46 and an engine speed sensor 47. The output signals of these sensors 46 and 47 are used to detect engine operating condition.
The controller 31 is mainly constructed of a microcomputer as shown in FIG. 6. It comprises an input/output interface 50, a ROM 51 which stores target coolant temperature values versus operating conditions arranged in a table as shown in FIG. 7, and a CPU 52.
FIG. 8 shows a flowchart of an operation routine of the microcomputer. In steps P1, P2 and P3, sensed actual coolant temperature TW1, intake manifold vacuum Pm and engine speed RPM are read, respectively, from th corresponding sensors 45, 46 and 47. In step P4, based on the intake manifold vacuum Pm and the engine speed RPM read in the previous steps, a target coolant temperature TW2 is retrieved by table look-up of FIG. 7. In step P5, the actual coolant temperature TW1 is compared with the target coolant temperature TW2. If TW1 is greater than or equal to TW2, the control goes to step P7 where electric current is allowed to pass through the solenoid 41 of the vacuum regulator 21 so as to energize same, whereas if TW1 is less than TW2, the control goes to step P6 where the supply of electric current to the solenoid 41 is cut off so as to deenergize same.
The supply of electric current to the solenoid 41 causes the valve element 42 to open the nozzle 39A, allowing the atmospheric air to enter via the vacuum line 43 into the vacuum chamber 26 of the flow control valve 20, decreasing the vacuum in the vacuum chamber 26. This causes the control valve 20 to increase opening degree thereof. As the control valve 20 increases its opening, the flow rate of coolant passing through the radiator 14 increases, thus bringing down the coolant temperature of the coolant to be supplied to an engine main body 13. When the electric current supply is cut off, the nozzle 39A is closed and the vacuum in the vacuum chamber 26 is increased. This causes the control valve 20 to decrease opening degree thereof, decreasing the flow rate of coolant passing through the radiator 14, thus allowing the coolant temperature to rise.
The system constructed as above operates as follows:
In response to the signals supplied from the intake manifold vacuum sensor 46 and the engine speed sensor 47, the controller 31 retrieves a target coolant temperature by table lock-up of the table shown in FIG. 7.
By looking up the table shown in FIG. 7, when the engine operates at low speeds with low load, a high temperature is set as the target coolant temperature. On the other hand, a low temperature is set as the target coolant temperature when the engine operates at high speeds with high load. Even with the same engine load, the target coolant temperature is shifted toward low temperature side as the engine speed increases, and the amount of shift from the high temperature side toward the low temperature side increases as the engine load increases.
After retrieving the target coolant temperature, the controller 31 compares the sensed actual coolant temperature TW1 with the target coolant temperature TW2.
If the target coolant temperature TW2 is set high, for example, as is required for operation at low speed with low load, the actual coolant temperature TW1 is lower than the target coolant temperature TW2. Thus, the controller 31 cuts off the supply of current passing through the solenoid 41, allowing the valve element 42 to close the nozzle 39A, admitting the vacuum within the regulating chamber 35 to the vacuum chamber 26, causing the diaphragm 25 to urge the valve element 23 against the return spring 28, decreasing the opening degree of the control valve 20 or rendering same zero.
This causes a decrease in flow of coolant passing through the radiator 14, resulting in an increase in temperature of the coolant circulating through a water jacket (not shown) in the engine main body 13.
This temperature is sensed by the coolant temperature sensor 45 and the sensor output is fed back to the controller 31.
If the actual coolant temperature TW1 exceeds the target coolant temperature, the controller 31 allows the supply of current to the solenoid 41, causing the valve element 42 of the vacuum regulator 21 to open the nozzle 39A, decreasing the vacuum supplied to the flow control valve 20. This allows the return spring 28 to push the valve element 23 of the control valve 20 in the valve opening direction, disengaging the valve element 23 from the seat portion 22. Thus, the flow rate of coolant passing through the radiator 14 increases, resulting in a drop in the coolant temperature. On the contrary, if the actual temperature TW1 drops again below the target coolant temperature TW2, the control valve 20 is closed again. After repeating these actions, the actual coolant temperature approaches the target coolant temperature optimum for low speed low load engine operation.
When, on the other hand, the engine operates at high speed with high load, the target coolant temperature TW2 is shifted toward the low temperature side.
Under this condition, the controller 31 allows the supply of current to the solenoid 41 of the vacuum regulator 21 so that the opening degree of the flow control valve 20 increases. This causes an increase in flow rate of coolant passing through the radiator 14, thus lowering the temperature of the coolant.
Since, owing to the feedback control, the opening degree of the control valve 20 is varied if the actual coolant temperature TW1 deviates from the target coolant temperature TW2, the coolant temperature is adjusted to a desired value with good accuracy even if the desired value changes as the engine operating condition changes. This may be readily appreciated from graphs shown in FIG. 9.
Since, in this embodiment, the flow control valve 20 is disposed on the discharge side of a water pump 17, the occurrence of cavitation which may be created by a lack in draw-in force by the water pump 17 can be prevented.
Although, in this embodiment, the solenoid actuating signal supplied to the vacuum regulator 21 is of ON-OFF form, the solenoid 41 may be actuated by varying ON-OFF duty of electric pulses with a predetermined frequency supplied to the solenoid 41. In the latter case, the coolant temperature may be adjusted to any target coolant temperatures with less deviation.
Describing the second embodiment shown in FIG. 10, a flow control valve 20 is disposed in an inlet passage 18 at a portion upstream of a junction where a bypass passage 16 joins with the inlet passage 18.
In this case, similarly to the before mentioned embodiment, the opening degree of the control valve 20 is feedback controlled in response to the output of a temperature sensor 45. Thus, the coolant temperature can be maintained at the optimum temperature for any operating condition.
In this second embodiment, although a valve element 23 of the flow control valve 20 is subjected to a draw-in pressure of a water pump 17 and biased in the valve opening direction, the force derived from the draw-in pressure of the water pump 17 is offset because the intake manifold vacuum is applied to a diaphragm 25, having substantially the same pressure acting area as that of the valve element 23, in order to create a force in a direction opposite to the valve opening direction.
Thus, the flow control valve 20 operates in good response to the control vacuum supplied to a vacuum chamber 26 without increasing the effective pressure acting area of the diaphragm 25. Besides, the opening degree of the control valve 20 is less affected by a variation in the draw-in pressure due to a variation in revolution speed of the water pump 17.
As described in the preceeding, according to the present invention the coolant temperature can be adjusted with good accuracy to different target coolant temperatures in response to different operating conditions, thus making it possible to improve fuel economy and exhaust characteristic without deteriorating the operating performance of the engine.
Besides, since the temperature sensor is provided independent of the flow control valve, the flow control valve can be actuated with good accuracy even if it is mounted in the inlet or the outlet of the coolant circulating circuit. Further, since there is no requirement on the structure of the control valve, any type of flow control valve may be used. Thus, a flow control valve with a diaphragm type actuator may be employed, making it possible to reduce the size of a valve actuator of a flow control valve. | A system for controlling a coolant temperature of an internal combustion engine comprises means for detecting operating condition of an engine, means for setting a different target coolant temperature for the detected operating condition, a flow control valve disposed in a coolant recirculating passage, and means for effecting a feedback control of opening degree of said flow control valve in such a manner as to adjust the actual coolant temperature toward the target coolant temperature. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a washing machine and more particularly, to a system for aligning a wash basket concentrically about the rotational axis of the basket in a manner that decreases runout.
2. Description of Related Art
Typically, a conventional vertical axis automatic washer has a tub and a wash basket vertically aligned within the tub. A drive block supports the wash basket and a spin drive tube extends longitudinally through apertures positioned centrally within the wash basket and drive block. The spin drive tube is driven by a motor that operates the spinning action of the wash basket. It is desired to have the wash basket concentric about a central axis extending the length of the spin drive tube to reduce wash basket runout during the spin cycle.
Conventional automatic washers have at least a wash and spin cycle. During the spin cycle, the spin drive tube drives the wash basket in a spinning motion to force wash liquid out of the wash basket and clothes. The wash basket may be spinning at a rate of 600 to 1000 rpm so it is important that the wash basket is aligned with the central axis or it will become out of balance and wobble or vibrate. When the wash basket becomes out of balance, it may hit the side of the wash tub causing noises. In extreme out of balance situations, the movement of the wash basket hitting the wash tub may cause the washer to “walk”. Additionally, since there is a current trend for higher wash basket capacity without an increase in the size of the cabinet frame, it is necessary to have lower tolerances to maintain control over the basket clearance.
In an automatic washer having a drive block supporting the wash basket, a portion of the drive block is inserted through a central aperture in the bottom of the wash basket and the wash basket bottom surface rests on another portion of the drive block. The spin drive tube extends through a central aperture in the drive block and in the wash basket bottom. The wash basket is fixed in position by a hold down nut that is threaded to the drive block inside the wash basket area or it may be fixed in position by one or more threaded fasteners. Therefore, if the wash basket is not aligned properly on the drive block, it will not be concentric about the central axis. Also, if the drive block is not aligned properly about the central axis, then the wash basket may not be concentric. So, it is important to have the overall alignment system of both the drive block and wash basket to provide a concentric spinning of the wash basket.
Traditional drive blocks are generally conical in shape and contact the generally conical outside surface of the wash basket bottom. Thus, the drive block and the wash basket abut circumferentially along a generally planar, conical surface. It is appreciated that there is basically one position in which the drive block and wash basket surfaces actually abut, but there are multiple possible positions for the drive block and wash basket to abut. Therefore, both the drive block and wash basket must be concentric about the central axis to obtain an accurate position.
Typically, the manufacturing process of an automatic washer includes the steps of configuring the drive block, spin drive tube, wash basket and hold down nut as close to concentric as possible. Acceptable tolerances for alignment about a central axis are determined for each step of the process; therefore, the tolerances stack up with each step. There would be better alignment about the central axis if the system of aligning the drive block and wash basket was done relative to each other to ensure overall concentricity of the spinning wash basket.
SUMMARY OF THE INVENTION
The present invention is directed to a system of aligning the wash basket of a washing machine concentrically about a central axis to decrease basket run out. The wash basket alignment system has a wash basket with a bottom wall having an outer surface and an inner surface, and a spin drive tube extending longitudinally along a generally central axis and through a central aperture in the basket bottom wall. Further, a rim defines the bottom wall central aperture and a wash basket center portion extends outward from the rim. The center portion is generally spherical in shape along the bottom wall inner surface. The wash basket has a mating portion extending outward from the center portion that is generally conical in shape along the bottom wall outer surface. There is a drive block having an upper portion with a central aperture for receiving the spin drive tube, a middle portion having a generally spherical shaped outside surface, and a threaded portion positioned between the upper portion and the middle portion.
It is an object of the invention to provide a wash basket alignment system wherein the drive block middle portion outside surface and the wash basket mating portion outer surface abut at a mating juncture when the drive block upper portion and threaded portion are inserted through the wash basket central aperture. The mating juncture is generally the circumference of a circle or ellipse.
Further, it is an object of the invention to provide a hold down nut having threads and a generally conical shaped underside surface with the threads mating with the drive block threaded portion. Additionally, the hold down nut underside surface and the wash basket center portion inner surface abut at a second juncture when the hold down nut threads are threadingly engaged with the drive block threaded portion. The second juncture is generally the circumference of a circle or ellipse.
It is an object of the invention to provide a hold down nut having threads and a generally conical underside surface with the hold down nut positioning the wash basket rim and central portion between the hold down nut and drive block middle portion when the hold down nut is threadingly engaged with the drive block threaded portion.
It is a further object of the invention to provide a hold down nut to position the mating portion outer surface with the drive block middle portion outside surface when the hold down nut is threadingly engaged with the drive block threaded portion. A circumferentially shaped mating juncture is formed that moves from a first position when the wash basket is not concentrically aligned about the central axis to a second position when the wash basket is concentrically aligned about the central axis.
Further, it is an object of the invention to provide a second juncture at which the wash basket center portion abuts the hold down nut conical shaped underside surface when the hold down nut threads threadingly engage the drive block threaded portion.
It is a further object of the invention to provide a mating juncture that may be shifted from a first position where the wash basket is not concentric about the central axis to a second position where the wash basket is generally concentric about the central axis, then the hold down nut can be threaded to the drive block threaded portion to maintain the second position. Further, the second juncture is shifted from a first position to a second position when the mating juncture is shifted from its first position to its second position and the second juncture second position is maintained by tightening the hold down nut to the drive block threaded portion.
It is a further object of the invention to provide a method of concentrically aligning a wash basket in an automatic washer having a spin drive tube extending longitudinally through a central aperture in the wash basket and a central aperture in a hold down nut and a central aperture in a drive block by positioning the wash basket aperture along a longitudinal axis, positioning the drive block aperture along the longitudinal axis, inserting a generally cylindrical portion of the drive block into the aperture of the wash basket thus having a portion of the drive block positioned within an interior area of the wash basket, resting an outer bottom surface of the wash basket on an outside surface of the drive block, threadingly engaging the hold down nut with mating threads on the drive block positioned in the interior area of the wash basket, spinning the wash basket along the longitudinal axis to determine concentricity of the wash basket, measuring concentricity of the wash basket along the longitudinal axis, aligning the wash basket along the longitudinal axis in response to the concentricity measurement, and tightening the threaded engagement of the lock nut to maintain the position of the wash basket.
It is also an object of the invention to provide a wash basket alignment system for an automatic washing machine having a wash basket with a bottom wall having an outer surface and an inner surface; a drive block with a middle portion having a generally spherical outside surface; and a generally central axis extending though a central aperture in the bottom wall and in the drive block. The drive block has a radius measured from a point on the central axis. The wash basket rim defines the wash basket central aperture, the wash basket center portion extends outward from the rim and is generally either spherical shaped or conical shaped. If the center portion is spherical shaped, it has a radius that intersects the central axis at a point.
It is an object of the invention to have the drive block point and the center portion point intersect the central axis at a common point when the center portion is spherical shaped.
Further, it is an object of the invention to provide a wash basket alignment system having a wash basket mating portion extending outward from the center portion that is either conical in shape or spherical in shape along the bottom wall outer surface. If the center portion is conical, a mating juncture is formed by the drive block middle portion and the mating portion such that a normal of the mating portion taken at the mating juncture passes through the drive block point. If the center portion is spherical, a mating juncture is formed by the mating portion and the drive bock middle portion such that the mating juncture is generally at a distance from the drive block point equal to the drive block radius.
It is also an object of the invention to provide a hold down nut having either a generally conical or convex underside surface, and a juncture formed by the center portion inner surface and the hold down nut underside surface. If the underside is conical then a normal of the hold down nut underside surface taken at the juncture passes through the drive block point.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view, partly in section, of a washing machine alignment system in accordance with the present invention.
FIG. 2 is a detailed sectional view of a portion of the wash basket and drive block showing the hold down nut in a threaded position.
FIG. 3 is a side elevational view of the drive block.
FIG. 4 is a perspective view of the hold down nut.
FIG. 5 a is a view taken along line 5 — 5 of FIG. 2 .
FIG. 5 b is an alternative embodiment of FIG. 5 a.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, reference numeral 20 indicates generally a washing machine of the automatic type, i.e., a machine having a pre-settable sequential controller 21 for operating a washer through a pre-selected program of automatic washing, rinsing and drying operations in which the present invention may be embodied. The controller 21 may be an electromechanical timer type device or an electronic microprocessor. The machine 20 includes a frame or cabinet 22 surrounding an imperforate tub 24 . A wash basket 26 with perforations or holes is rotatably supported within the tub. A fill valve 25 is connected to an external water supply (not shown) and is operated to inlet water into the tub 24 . A hinged lid 28 is provided in the usual manner to provide access to the interior of the wash basket 26 .
The wash basket 26 defines a wash chamber 36 and includes a generally cylindrical side wall 30 and a vertical center axis C—C. The side wall 30 includes a partly spherical wall portion 34 adjacent a bottom wall 32 . A motor 40 is operatively connected to the basket 26 through a transmission 42 to rotate the basket 26 relative to the stationary tub 24 . A suspension frame 44 supports the motor and tub assembly within the cabinet 22 . The controller 21 is operatively interconnected with the motor and the fill valve 25 such that the controller 21 can operate the washer 20 according to the selected program cycle.
Positioned within the lower portion of the wash basket 26 is a bottom wash plate 50 . The bottom wash plate 50 may be of the type having an annular body 52 and a raised center dome 54 . The surface of the wash plate 50 may have vanes or other protrusions.
Turning now to FIG. 2, details of the wash plate drive system may be described. A spin tube 60 is co-axially arranged around an output shaft 62 , both of which are drivingly interconnected with the transmission 42 . The axes of the spin tube 60 and the output shaft 62 are generally aligned with the center axis C—C. A brake mechanism operates in association with the spin tube 60 and the output shaft 62 for braking the rotation of the spin basket 26 . The brake mechanism may be of the type shown in detail in U.S. Pat. No. 4,254,641 to Gauer et al. having the same assignee as the present invention, the disclosure of which is hereby incorporated by reference.
As shown in FIGS. 1 and. 2 , the spin tube 60 extends through an aperture 38 in the tub 24 and is attached to the wash basket 26 by a drive block 66 . A hold down nut 68 is threaded onto the drive block 66 such that a portion of the wash basket 26 is clamped between the drive block 66 and the hold down nut 68 . It can be seen that the aperture 38 in the tub 24 is generally aligned with a central aperture 72 in the wash basket 26 along the center axis C—C.
It can be seen in FIGS. 2 and 3 that the drive block 66 has an upper portion 74 , a threaded portion 76 , a middle portion 78 and a lower portion 80 . The threaded portion is positioned between the upper portion and the middle portion. The upper portion 74 comprises a generally tubular portion 82 positioned above a joint assembly area 64 where the wash plate can be mounted to the spin drive tube. There is an aperture 84 extending along the length of the upper portion for receiving the output shaft 62 . The aperture 84 is positioned generally along the center axis C—C. The upper portion may have threads 86 positioned along the outside surface 88 of the tubular portion 82 so the drive block upper portion can be threadingly mated with the spin tube, if so desired.
The threaded portion 76 is generally circular and is of a greater diameter than the upper portion 74 . The middle portion 78 is generally circular and is of a greater diameter than the threaded portion 76 . When the upper portion is inserted from outside the basket, upward and through the wash basket aperture 72 , the threaded portion 76 is also inserted through the aperture. The wash basket then abuts the middle portion 78 of the drive block, which remains outside of the wash basket.
A hold down nut 68 threadingly engages the threaded portion 76 of the drive block. The nut shown in FIG. 4 has a generally circular circumference 92 and threads 70 positioned along the inner wall 46 of the nut aperture 48 . Once the upper portion 74 and the threaded portion 76 of the drive block are inserted into the wash basket aperture 72 , the nut 68 can be threaded onto the drive block threaded portion 76 , thereby maintaining the wash basket in a position abutting the drive block middle portion 78 . It is desirable to align the center axis C—C with the drive block aperture 84 and the wash basket aperture 72 in such a way as to reduce runout when the wash basket is in the spin cycle.
The hold down nut has an upper surface 56 that is positioned toward the interior of the wash basket and an underside surface 58 that is positioned toward the drive block middle portion 78 when the hold down nut is threaded to the drive block. The underside 58 may either be either generally conical or spherical (convex) in shape, sloping downward from a first circumference 90 to a second circumference 92 . The first circumference is positioned at the hold down nut threads 70 and is less than the second circumference.
The outside surface 94 of the drive block middle portion 78 is generally spherical in shape with a radius R 1 that intersects the center axis C—C at point P as shown in FIG. 2 . Therefore, point P is generally the center of the spherical portion of the drive block 66 . It can be seen in FIG. 3, that the middle portion has an inner circumference 96 at the juncture of the threaded portion 76 and the middle portion and an outer circumference 98 at the juncture of the middle portion and the lower portion 80 . The middle portion of the drive block slopes downward from the inner circumference 96 to the outer circumference 98 with a gently spherical slope providing a generally spherical outside surface area 94 for the middle portion.
As seen in FIGS. 5 a and 5 b , the bottom wall 32 of the wash basket 26 has an inner surface 100 positioned toward the wash chamber 36 and an outer surface 102 positioned toward the drive block 66 . A portion of the outer surface 102 abuts the drive block middle portion outside surface 94 when the drive block upper portion 74 and threaded portion 76 are inserted into the wash basket aperture 72 . It will be appreciated that the outer basket surface 102 and middle portion 78 abut along a generally circular or elliptical mating juncture 104 . The mating juncture is located along the spherical surface 94 thus being at a radius from the center axis C—C generally equal to the radius R 1 of the drive block middle portion 78 .
The wash basket aperture 72 is generally positioned at the center of the bottom wall 32 of the wash basket. The bottom wall is generally annular and there is a rim 106 defining the circumference of the aperture 72 . The bottom wall has a center portion 108 extending outwardly from the rim. The inner surface 100 of the basket's center portion 108 may be either generally conical or spherical (convex) in shape. The center portion extends further outward into a mating portion 110 . The outer surface 102 of the basket's mating portion may be either generally conical or spherical (convex) in shape. There may be a bridging portion 112 between the center portion 108 and the mating portion 10 that is of any shape to allow for the transition between the center portion and the mating portion. The bridging portion is shown in FIG. 5 a as a sloping conical portion and in FIG. 5 b as a corner that distinguishes the center portion from the mating portion. From the mating portion 110 to the partly spherical wall portion 34 there is an end portion 114 . The surfaces of the end portion 114 can be a variety of shapes and slopes so long as it is suitable for allowing a wash plate 50 to be positioned above it. As seen in FIG. 2, the end portion 114 may slope downward from the mating portion 110 then flatten to meet the partly spherical wall portion 34 .
Once the upper portion 74 and the threaded portion 76 of the drive block 66 have been inserted into the basket aperture 72 , the mating portion 110 of the basket abuts the spherical surface 94 of the drive block middle portion 78 . The mating juncture 104 is formed by either a generally spherical or conical shaped mating portion 110 of the basket and the spherical shaped surface of the drive block middle portion 78 . The radius of the mating juncture 104 is equal to R 1 . If the mating portion 110 is conical shaped, then a normal (a perpendicular line) of the mating portion taken at the mating juncture will intersect the center axis C—C at point P. The mating juncture 104 is generally circular or elliptical and substantially concentric with the center axis C—C. Since the mating portion 110 can shift on the spherical shaped drive block middle portion, the basket can be moved into concentric alignment with the center axis C—C so that basket runout is minimized. The combination of either a spherical and spherical surface or a spherical and conical surface abutting at the mating juncture 104 allows the operator to position the basket 26 and the drive block 66 on the spin tube 60 , spin the basket, test for basket runout, then shift or alter the mating juncture to reduce basket runout. The drive block radius R 1 and the mating juncture normal will still intersect the center axis at point P.
Basically, basket runout is a measure of the overall concentricity of the basket. This measurement may be performed with a simple device that uses a reciprocating pin positioned perpendicular to the outer surface of the side wall of the basket. The distance from the center axis to the device is the desired radius of the basket so the actual radius is measured and adjustments made accordingly. At rest, the pin is at measurement 0. The basket then spins and the pin reciprocates in and out in response to the outer surface of the basket. The difference between the highest number and lowest number is the total basket runout. If the measurement is outside acceptable tolerances, then the wash basket is repositioned for concentric alignment.
As described above, the hold down nut 68 has an underside surface 58 that is generally spherical or conical in shape. When the nut threads 70 are threaded onto the threaded portion 76 of the drive block 66 , the underside surface 58 abuts the bottom wall 32 of the wash basket. Since the upper portion 74 and the threaded portion 76 of the drive block are inserted into the aperture 72 of the wash basket, the nut 68 is threaded onto the threaded portion 76 from the interior chamber 36 of the basket, thereby trapping the basket bottom wall 32 between the nut 68 and the drive block middle portion 78 . The nut underside surface 58 abuts the bottom wall inner surface 100 at the center portion 108 forming a generally circular or elliptical juncture 116 . Thus, the juncture 116 is formed by a conical or spherical (convex) center portion of the basket bottom wall and a spherical or conical underside surface of the nut. In the wash basket alignment system, the combination of the center portion 108 and the underside surface 58 of the nut is either a spherical surface and a spherical surface or a spherical surface and a conical surface; not a conical surface and a conical surface. If the underside of the nut 58 is spherical and the center portion inner surface is spherical or conical, then the radius R 2 of the nut underside intersects the center C—C at point P. If the underside of the nut 58 is conical and the center portion 108 is spherical, then the normal N of the nut underside surface taken at juncture 116 intersects the center C—C at point P. The wash basket is aligned about the center axis C—C to reduce basket runout by adjusting the second juncture 116 formed by the hold down nut 68 and wash basket 26 and the mating juncture 104 formed by the wash basket 26 and drive block 66 . Since the second juncture 116 comprises either a spherical surface and a conical surface or a spherical surface and a spherical surface, the juncture can be shifted or rolled to allow for concentricity of the wash basket about the center axis. This second juncture 116 is automatically shifted, as the mating juncture 104 , which is comprised of the drive block middle portion surface 94 and the outer surface of the wash basket mating portion, is shifted. If a measurement has been taken that indicates basket runout, the mating juncture 104 is shifted to provide a more concentric spinning action of the basket about the center axis C—C. Once an appropriate runout tolerance is reached, the hold down nut 68 can be threadingly tightened. It will be appreciated that the position of the mating juncture generally determines the position of the second juncture 116 . The configuration of spherical and spherical and/or conical surfaces at each of the junctures prevents the tightening of the hold down nut from causing the junctures to shift because the radius and normal measurements intersect the center axis C—C at common point P. Thus, the wash basket 26 can be generally aligned about the center axis C—C of the spin tube 66 in such a position as to minimize basket runout. This alignment method allows each basket to be individually aligned concentrically during the manufacturing or assembly process to decrease basket runout.
In the wash basket alignment system, the normal of the conical surfaces and the radius of the spherical surfaces intersect at a common point P on the center axis C—C thus allowing the mating juncture and second juncture to remain in place when the hold down nut is tightened. One method of configuring the wash basket alignment system involves manufacturing the spherical drive block then centering it about the center axis C—C. The radius is measured, thus defining the center point P at which the center axis C—C is intersected. The wash basket is manufactured with a bottom plate having a mating portion 110 that is either conical or spherical along the outer surface 102 and a center portion that is either conical or spherical along the inner surface 100 . If the center portion 108 is conical along the inner surface 100 , then the underside 58 of the hold down nut will be spherical. If the center portion 108 is spherical along the inner surface 100 then the underside 58 of the hold down nut may be either spherical (convex) or conical in shape. The radius of the spherical surfaces will be manufactured such that the center point P intersects the center axis C—C at the same point P as the drive block radius R 1 . If the mating juncture and second juncture have a common point P on the center axis C—C (either a radius or normal intersection) then an operator can apply horizontal force to the wash basket to move it from side to side, thus moving the junctures but maintaining the common point P and allowing for concentricity of the wash basket. If the basket runout measurement is outside of acceptable tolerances then this adjustment is made.
It can be seen, therefore, that the present invention provides a system for improving the concentricity of a wash basket to minimized basket runout. While the present invention has been described with reference to the above described embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the scope of the invention as set forth in the appended claims. | A wash basket alignment system for an automatic washing machine having a wash basket with a drive block partially inserted through a central aperture in the bottom wall of the wash plate. A spin drive tube extends longitudinally through the central aperture in the drive block and through the wash plate bottom wall. A hold down nut is threadingly engaged to the drive block from the inside chamber of the wash basket to position the wash basket within the wash tub. Concentric alignment of the wash basket along a central longitudinal axis decreases basket runout. Therefore, the drive block has a spherical outside surface where it abuts the conical shaped outer surface of the wash basket. The radius of the spherical outside surface intersects the central axis at a point. This configuration facilitates the sliding or moving of this juncture from a first position out of concentricity to a second position that is concentric about the longitudinal axis. Additionally, the hold down nut has a conical shaped underside surface where it abuts the spherical shaped inner surface of the wash basket. A normal taken at this abutment passes through the same point on the central axis. This configuration facilitates movement from a first position out of concentricity to a second position with the wash basket concentric about the longitudinal axis. These two junctures are maintained by tightening the hold down nut. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to electrical resistors and, more particularly, to resistor units for use in motor starters or other electric apparatus which are exposed to moderate vibration and industrial environment.
2. Description of the Prior Art
Electric resistance units of prior construction have required strips of asbestos dipped in a water glass solution to mount the porcelain insulators on a steel support bar. Since steel and porcelain are rigid materials, it was necessary to provide padding between them to hold them together during subsequent winding of a helical resistor element around the assembled bar and insulators. The asbestos strips also prevented the bar and insulators from subsequently rattling.
Inasmuch as asbestos is detrimental to people's health, it has been deemed desirable to replace the asbestos strips with a non-detrimental material.
SUMMARY OF THE INVENTION
In accordance with this invention, it has been found that a more desirable resistor unit is available which comprises an elongated support rod, a plurality of insulating refractory bodies on the rod in end-to-end abutment and arranged to substantially surround the rod, the bodies being of shorter length than the rod, each body having a groove to fit the rod, a continuous resistance winding helically mounted on and surrounding the refractory bodies, flexible metal mounting means in the groove and between the rod and the bodies for retaining the bodies on the rod, the insulator mounting means comprising corrugated strips of metal having alternate ridges and grooves with the grooves adjacent to the support rod, the ends of the ridges being beveled or the end portions being formed inwardly to provide inwardly inclined ends to facilitate assembly of the bodies on the rod, and water glass adhesive being disposed between the rod and the bodies.
The advantage of the device of this invention is that the corrugated or formed spring strips not only provide a flexible mounting means for relatively fragile ceramic insulators, but also eliminate the current asbestos padding now used to secure insulators on the mounting bar.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of an electric resistor unit in accordance with this invention;
FIG. 2 is a vertical sectional view taken on line II--II of FIG. 1;
FIG. 3 is an exploded view showing the manner in which the unit is assembled;
FIG. 4 is a plan view of a strip of corrugated sheet metal;
FIG. 5 is an enlarged fragmentary view taken on the line V--V of FIG. 4;
FIG. 6 is a vertical sectional view taken on the line VI--VI of FIG. 5;
FIG. 7 is a plan view of corrugated sheet metal of another embodiment;
FIG. 8 is an enlarged fragmentary view taken on the line VIII--VIII of FIG. 7;
FIG. 9 is a vertical sectional view taken on the line IX--IX of FIG. 8;
FIG. 10 is a plan view of another embodiment of the metal strip; and
FIG. 11 is a vertical sectional view taken on line XI--XI of FIG. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, an electric resistor unit assembly is generally indicated at 1, and it comprises an elongated support rod or strap 3, a plurality of insulating refractory bodies 5, and a helical resistance winding or conductor 7. The unit is adapted for mounting on support bars in a conventional manner for which reason the support rod 3 comprises similar hooks or slots 9 for facilitating the mounting.
The rod 3 is an elongated strap having a rectangular cross section (FIG. 2) and is preferably comprised of a suitable heat resisting metal.
The insulators or refractory bodies 5 are molded members of ceramic material such as porcelain. Each refractory body 5 has a transverse U-shaped cross section forming a longitudinal slot 11. As shown in FIG. 2, the rod fits into the slots 11 on upper and lower sides thereof so that the rod is substantially enclosed within the slots 11 which are disposed in facing relationship on the rod so that the rod is substantially contained within the refractory bodies 5. The bodies 5 are disposed longitudinally in end-to-end abutment with each other over the length of the rod 3. Moreover, the upper and lower edges of each pair of oppositely-disposed bodies 5 include suitable spaced notches 13 which are separated by projections 15 to provide a threaded support for the helical resistor winding 7.
When the refractory bodies 5 are assembled on the rod 3 in the manner shown in FIG. 3, the assembly is then rotated on the longitudinal axis of the rod to assemble the resistance winding 7 by threading it through the notches 13. Terminals 17, 19 (FIG. 1) are provided for making electrical connections to opposite ends of the winding 7.
In accordance with this invention, a formed metal strip 21 is disposed in the slot 11 in the space between the rod 3 and the sidewalls 23 of the refractory bodies 5 forming the slots 11. The metal strip 21 is disposed preferably on each side of the rod 3 for securing the bodies 5 in place on the rod. More particularly, each metal strip 21 is a flexible member having a non-planar configuration to create friction between the rod and the bodies 5, thereby preventing the bodies from falling off of the rod inadvertently. As shown in FIGS. 4 and 5, the metal strips 21 may have a sinuous or corrugated configuration with alternate ridges 25 and grooves 27 so that the strips 21 are compressed between the rod and the sidewalls 23 of the refractory bodies 5.
To eliminate any difficulty of inserting the bodies 5 onto the rod 3 due to sharp corners at opposite ends of the ridges 25, the opposite edges of the metal strip 21 may be ground to beveled edges 29, 31. The grooves 27 are thereby placed against the sides of the rod 3 with the ridges 25 against the sidewalls 23 of the bodies 5.
During the moderately high speed rotation of the assembled rod 3 and bodies 5 when the resistance winding 7 is threaded in place around the assembly, centrifugal force may be sufficiently great to cause some of the bodies to slip out of place or fly off of the rod. Accordingly, strips 32, 34 (FIGS. 2, 3) of adhesive material are applied on edges in the longitudinal space between the bodies 5. A suitable adhesive material 32, 34 for that purpose is a water glass solution.
In FIGS. 7, 8, and 9, another embodiment of a metal strip 33 is shown. The strip 33 also includes alternate ridges 35 and grooves 37 similar to the strip 21. However, the strip 33 instead of having ground beveled edges 29, 31 are provided with formed or bent-in edges 39, 41 (FIG. 9) to facilitate the mounting of the refractory bodies 5 onto the rod 3.
Another embodiment of a metal strip 43 is shown in FIG. 10 in which at least one and preferably two or more rows of lanced projections 45 are provided along one edge of the metal strip 43 and another set or rows of lanced projections 47 are provided on the other side thereof. The projections 45, 47 are disposed at angles less than 90° and preferably 80° to the surface of the strip 43. Accordingly, when the refractory bodies 5 are in place, the shart edge, lanced projections 45, 47 deflect to retain them in place on the rod 3.
In conclusion, the device of this invention provides suitable means for mounting the refractory bodies in place on the metal rod which mounting means are flexible and disposed between the rigid, unyielding rough surfaces of the rod and bodies. The flexible mounting means eliminate the use of objectionable asbestos padding and prevent the bodies from rattling on the bar. | An electric resistance unit characterized by a support rod with a plurality of insulating refractory bodies thereon, which bodies have grooves to fit the rod, a continuous resistance winding mounted around the bodies, and flexible metal mounting means in the groove and between the rod and the bodies for retaining the bodies on the rod. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of U.S. application Ser. No. 11/338,409, filed Jan. 24, 2006 now abandonded and entitled “Lock Out Mechanism For Vehicle Door Outside Handles” which claims priority to and all the benefits of U.S. provisional application No. 60/646,759, filed Jan. 24, 2005.
FIELD OF THE INVENTION
This invention relates to an outside handle assembly for a motor vehicle. More particularly, the invention relates to a locking mechanism for preventing inadvertent release of a motor vehicle door when a handle portion of a handle assembly moves at an acceleration above a predetermined threshold.
DESCRIPTION OF THE PRIOR ART
Motor vehicles include at least one outside door handle for releasing a door latch mechanism in order to open a door. Typically, a user actuates the outside door handle by pivoting a handle portion relative to a base. The handle portion may, however, also be pivoted when the outside door handle is exposed to a high inertia force. The pivoting of the handle portion relative to the base in response to the high inertia force can cause inadvertent opening of the door.
In recent years, there has been development of locking mechanisms to attempt to prevent the opening of a vehicular door in the event of such a high inertia force. While the existing mechanisms work for some crash situations, there is a need in the art for a locking mechanism that does not allow the vehicle door to open in the event of a high acceleration impact or during a vehicle rollover.
SUMMARY OF THE INVENTION
According to one aspect of the invention, there is provided a handle assembly for selectively allowing the door latch of a door of a motor vehicle to be released. The handle assembly includes a base fixedly secured to the door. The handle assembly also includes a handle portion and a lock trigger. The handle portion is operatively connected to a door latch mechanism effectuating the opening of the door. The lock trigger is movably engaged with the handle portion to allow or disallow the movement of the handle assembly and hence the opening of the door.
BRIEF DESCRIPTION OF THE DRAWINGS
Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 is a side view of a motor vehicle including a handle assembly;
FIG. 2 is a perspective view of a first embodiment of a handle assembly in a locked position;
FIG. 3 is a cross-sectional view taken along lines 3 - 3 of the handle assembly in the locked position;
FIG. 4 is a cross-sectional side view of a second embodiment of a handle assembly in a locked position;
FIG. 5 is a cross-sectional side view of the second embodiment of the handle assembly in an unlocked position;
FIG. 6 is a top view of a third embodiment of a handle assembly;
FIG. 7 is a perspective view of the handle assembly of FIG. 6 ; and
FIG. 8 is a perspective view of a lock trigger of the handle assembly of FIGS. 6 and 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , a handle assembly, generally indicated at 10 , is mounted to a door 12 of a motor vehicle 14 . The handle assembly 10 is operatively connected to a door latch mechanism 16 . When the door latch mechanism 16 is unlocked, the handle assembly 10 may be actuated from outside the motor vehicle 14 to unlatch the door latch mechanism 16 and open the door 12 .
Referring to FIG. 2 , a first embodiment of the handle assembly 10 includes a base 18 adapted to be fixedly secured to the door 12 . The base 18 defines an aperture 20 having a handle edge 20 a and a lock edge 20 b . A handle portion 22 is pivotally coupled to the base 18 at the handle edge 20 a . The handle portion 22 includes a grip 24 that is manually grasped by a user for pivoting the handle portion 22 at the handle edge 20 a relative to the base 18 in order to actuate the handle assembly 10 . The handle portion 22 pivots outwards from and back towards the base 20 and is operably connected to the door latch mechanism 16 .
The handle assembly 10 also includes a lock trigger 28 pivotally coupled to the base 18 at the lock edge 20 b of the aperture 20 for preventing inadvertent release of the door latch mechanism 16 when an unintended force causes the handle portion 22 to pivot relative to the base 20 . The lock trigger 28 moves inwardly to unlock the handle portion 22 and back towards the outer face of the base 18 to lock the handle portion 22 . The lock trigger 28 locks the handle portion 22 by abutting thereagainst preventing the pivotal movement of the handle portion 22 . Referring to FIG. 3 , a cross section of the handle assembly 10 is shown along lines 3 - 3 of FIG. 2 . The handle portion 22 and the lock trigger 28 are shaped such that pivoting of the handle portion 22 outward in the direction shown by the arrow C about the handle edge 20 a of the base 18 is prevented unless the lock trigger 28 is first pivoted inward in the direction shown by the arrow D about the lock edge 20 b of the base 18 .
Referring to FIG. 4 , wherein like primed reference numerals represent similar elements as those described above, a second embodiment of the handle assembly 10 ′ is shown. The handle assembly 10 ′ includes a base 18 ′ adapted to be fixedly secured to the door 12 ′. The handle assembly 10 ′ further includes a handle portion 22 ′ operatively connected to the door latch mechanism 16 ′ and a lock trigger 28 ′ for preventing inadvertent release of the door latch mechanism 16 ′.
The handle portion 22 ′ is pivotally coupled to the base 18 ′ by a first pivot pin 29 . A handle bias spring 30 , operatively connected to the pivot pin 29 , biases the handle portion 22 ′ towards the base 18 ′. The handle portion 22 ′ further includes an internal handle arm 32 and a grip 24 ′ that is manually grabbed by a user for pivoting the handle portion 22 ′ relative to the base 18 ′ in order to actuate the handle assembly 10 ′. The handle portion 22 ′ pivots about the pivot pin 29 and is operatively connected to the door latch mechanism 16 ′. Preferably the grip 24 ′ is substantially L-shaped to facilitate a user pulling the handle portion 22 ′ with a cupped hand, but it should be appreciated that the grip 24 ′ could be a variety of shapes. The handle portion 22 ′ also includes a lock tab 44 and will be discussed in more detail hereinbelow.
The lock trigger 28 ′ is pivotally coupled to the base 18 ′ by a second pivot pin 35 . The lock trigger 28 ′ includes a lock arm 36 that abuts the grip 24 ′ to prevent the user from grabbing and pulling the grip 24 ′ without first activating the lock trigger 28 ′ by pivoting (pushing) the lock trigger 28 ′ towards the base 18 ′. The handle assembly 10 ′ further includes a hook lever 40 pivotally coupled to the base 18 ′ by a third pivot pin 42 , for preventing pivoting of the handle portion 22 ′ until the lock trigger 28 ′ has been activated. A positioning spring 43 , operatively connected to the third pivot pin 42 , biases the hook lever 40 to selectively abut against the lock trigger 28 ′ and interfere with the movement thereof. The hook lever 40 includes a handle tab 46 that extends upwardly therefrom. When locked, the handle tab 46 interferes with the handle portion 22 ′ by blocking the path of the lock tab 44 , thus preventing pivoting of the handle portion 22 ′.
In operation, the handle assembly 22 ′ starts in the locked position as shown in FIG. 4 . In the locked position, the handle tab 46 of the hook lever 40 engages with the lock tab 44 of the handle portion 22 ′ to prevent pivoting of the handle portion 22 ′ and thereby preventing the opening of the door 12 ′. In order to open the door 12 ′, the user must first push the lock trigger 28 ′ inwards (counterclockwise movement when viewed from FIG. 4 ) causing the lock trigger 28 ′ to pivot towards the base 19 ′. As the lock trigger 28 ′ pivots about the second pivot pin 35 , it operatively engages the hook lever 40 , thereby causing the hook lever 40 to pivot against the positioning spring 43 (clockwise movement when viewed from FIG. 4 ). The pivoting of the hook lever 40 causes the handle tab 46 to move away from its blocking orientation of the lock tab 44 of the handle portion 22 ′, as shown in FIG. 5 . Once the user has pushed the lock trigger 28 ′ inwardly (or inboard), and the handle tab 46 has moved away from the lock tab 44 , the user may then pull or pivot the grip 24 ′ of the handle portion 22 ′ to activate the door latch mechanism 16 ′ and open the door 12 ′. Once the user releases the handle portion 22 ′ and the lock trigger 28 ′, the handle bias spring 30 and positioning spring 43 urge the handle assembly 10 ′ to return to the locked position.
Referring to FIGS. 6 through 8 , wherein like double primed reference numerals represent similar elements as those described above, a third embodiment of the handle assembly 10 ″ is shown. The handle assembly 10 ″ includes a base 18 ″ adapted to be fixedly secured to the door 12 ″. The base 18 ″ includes a leg aperture 50 having a relief 51 . The handle assembly 10 ″ further includes a handle portion 22 ″ having an outboard side 52 and an opposite inboard side 54 , the handle portion 22 ″ being operatively connected to the door latch mechanism 16 ″ and a lock trigger 28 ″. The handle portion 22 ″ includes a grip 24 ″ that is manually grabbed by a user for pulling the handle portion 22 ″ in an outboard direction relative to the base 18 ″ in order to actuate the handle assembly 10 ″. The handle portion 22 ″ has a door end 56 and an opposite, base end 58 . The base end 58 further includes a leg 60 extending outwardly therefrom into the door 12 ″ and extending through the leg aperture 50 of the base 18 ″, allowing for a sliding engagement between the leg 60 and the leg aperture 50 . The door end 56 of the handle portion 22 ″ is adapted to be pivotally engaged with the door 12 ″.
With this configuration, the handle assembly 10 ″ operates as a strap type outside handle as is known in the art. Typically, the user will grasp the grip 24 ″ of the handle portion 22 ″ and pull the handle portion 22 ″ outboard relative to the base 18 ″. Pulling the handle portion 22 ″ causes the door end 56 of the handle portion 22 ″ to pivot relative to the door 12 ″ while the leg 60 at the base end 58 slides through the leg aperture 50 allowing the base end 58 of the handle portion 22 ″ to extend away from the base 18 ″.
The leg 60 of the handle portion 22 ″ includes a stop tab 62 having a fixed end 63 and an opposite stop end 64 . The fixed end 63 of the stop tab 62 is fixedly secured to the leg 60 while the stop end 64 is movable relative to the leg 60 in a springboard-like motion. The stop end 64 of the stop tab 62 includes a boss 65 which abuts the relief 51 of the leg aperture 50 , thereby preventing the leg 60 from sliding through the leg aperture 50 in an outboard direction.
The lock trigger 28 ″ is located on the inboard side 54 of the handle portion 22 ′. The lock trigger 28 ″ selectively disengages the boss 65 of the stop tab 62 from the relief 51 of the leg aperture 50 to allow the sliding of the leg 60 through the aperture 50 and thereby release the door 12 ″. Referring to FIG. 8 , the lock trigger 28 ″ has a mounting end 66 and a distal end 68 . The mounting end 66 includes a spring 70 , preferably a cantilever spring, fixedly attached to the mounting end 66 by a mounting pin 72 . The lock trigger 28 ″ is pivotally attached to the base end 58 of the handle portion 22 ″ by the mounting pin 72 as shown in FIGS. 6 and 7 . The mounting pin 72 defines a pivot axis, which is located such that full inertia balancing of the lock trigger 28 ″ is possible. The spring 70 urges the lock trigger 28 ″ away from the handle portion 22 ″. The mounting end 66 of the lock trigger 28 ″ further includes a tip 74 for engagement with the stop tab 62 of the leg 60 . When the lock trigger 28 ″ is pulled toward the handle portion 22 ″, the tip 74 of the lock trigger 28 ″ slides over the boss 65 of the stop tab 62 , thereby pressing the stop tab 62 towards the leg 60 . Once pressed towards the leg 60 , the boss 65 of the stop tab 62 no longer abuts the relief 51 of the leg aperture 50 , thereby allowing the leg 60 to slide through the aperture 50 in an outboard direction.
In operation, the lock trigger 28 ″ prevents the normal operation of the user pulling the handle portion 22 ″ to open the door 12 ″ unless the lock trigger 28 ″ is first activate. When in the locked position, the cantilever spring 70 of the lock trigger 28 ″ urges the lock trigger 28 ″ away from the handle portion 22 ″. When in this position, the tip 74 of the lock trigger does not pressingly engage the boss 65 of the stop tab 62 . As such, the boss 65 abuts the relief 51 of the leg aperture 50 , thereby preventing movement of the handle portion 22 ″ in the outboard direction by preventing the sliding movement of the leg 60 through the leg aperture 50 . Thus, if a force is applied to pull the handle portion 22 ″ in an outboard direction without engaging the lock trigger 28 ″, the handle assembly 10 ″ is locked and will not allow release of the door 12 ″.
To unlock the handle assembly 10 ″ and release the car door 12 ″, the operator must first pull the lock trigger 28 ″ toward the handle portion 22 ″ (outward movement relative to the door 12 ″). As the lock trigger 28 ″ is urged toward the handle portion 22 ″, the tip 74 of the lock trigger 28 ″ moves over the boss 65 of the stop tab 62 , pressing the stop end 64 of the stop tab 62 towards the leg 60 . Once the stop tab 62 is pressed towards the leg 60 , the boss 65 no longer abuts the relief 51 of the leg aperture 50 , unlocking the handle assembly 10 ″ by allowing the leg 60 to slide through the aperture 50 . Once unlocked, the operator can pull the handle portion 22 ″ in an outboard direction to activate the door latch mechanism 16 ″ and release the door 12 ″.
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used, is intended to be in the nature of words of description rather than of limitation.
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 other than as specifically described. | A handle assembly selectively allows the door latch of a door of a motor vehicle to be released. The handle assembly includes a base fixedly secured to the door. The handle assembly also includes a handle portion and a lock trigger. The handle portion is operatively connected to a door latch mechanism effectuating the opening of the door. The lock trigger is movably engaged with the handle portion to allow or disallow the movement of the handle assembly and hence the opening of the door. | 4 |
BACKGROUND OF THE INVENTION
[0001] I. Field of the Invention
[0002] This invention relates generally to portable machining lathes, and more particularly to a machine for re-facing worn, corroded, pitted and leaking gasket seat surfaces of oval manways commonly found on pressurized industrial vessels such as tanks, steamlines, pipelines, etc.
[0003] II. Discussion of the Prior Art
[0004] Industrial facilities, such as power generating plants, petroleum processing plants and other like facilities have high pressure tanks and pipelines that commonly incorporate sealed entrance ports called manways. Maintenance personnel can use the manways to gain access to the interior of the vessel.
[0005] In many instances, these access ports have an oval or elliptical profile. With time, the gasket seat surface between the manway and the vessel may become pitted, corroded and worn to the point where leaks develop. When this happens, it becomes necessary to reface the gasket seat area. To minimize the downtime of the industrial production, it is imperative that the re-facing be accomplished in situ.
[0006] One approach for re-facing oval manways in the past has been to use a grinder such as the Oval Manway Seat Grinder commercially available from the D. L. Ricci Corp., the assignee of the present application. This grinder produces a very smooth, fine finish on the manway seat area. However, in some applications, such a smooth surface is disadvantageous. More particularly, in high pressure applications, the gasket used between the manway and the vessel can be extruded radially outwardly due to the high pressures encountered. It is, therefore, desirable in such high pressure applications that the re-surfacing of the gasket seat area result in a slightly ridged surface resembling the somewhat concentric grooves of a phonograph record. This roughened surface has been found to inhibit gasket extrusion even under very high pressures developed within the vessel in question.
[0007] It is unduly heavy, making it difficult to set up from a location outside of the vessel. Also, the opening of the oval manway is substantially occluded, making adjustments from outside of the vessel and observation of the surface being machined difficult to do.
SUMMARY OF THE INVENTION
[0008] The present invention provides an improved machine for re-surfacing the face of an oval manway gasket seat. It includes a housing having first and second oval-shaped major surfaces having an oval-shaped central opening that is formed through the thickness dimension of the housing. The housing is designed to fit within and be supported by an oval manway to be machined. It has a first track member affixed to the first major surface in surrounding relation to the oval-shaped central opening. Likewise, a second track member is disposed on the second major surface, also in surrounding relation to the central opening. A drive means supported by the housing and cooperating with the first track member causes the drive means to orbit the oval-shaped central opening when the drive means is energized. The drive means carries a bracket member having an arm that extends through the oval-shaped central opening. The arm pivotally supports a link member that is operatively coupled to the second track member and that link member carries a machine tool slide assembly in an orbital path defined by the second track member. The machine tool slide assembly supports a cutting tool for engaging the face of the oval manway.
[0009] The machine tool slide assembly comprises a cam actuated feed screw for incrementally translating the cutting tool in a radial direction as the machine tool slide assembly is carried in its orbital path.
[0010] Because the central opening of the housing does not become blocked by the tool slide assembly and structure supporting it, an operator, from the outside, can reach through the central opening to make depth-of-cut adjustments and can selectively engage and disengage the cam actuated lead screw that controls the radial translation of the cutting tool. Moreover, because the oval manway is not appreciably blocked or occluded by the facer assembly, the surface being worked can be readily viewed.
DESCRIPTION OF THE DRAWINGS
[0011] The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several view is referred to corresponding parts.
[0012] [0012]FIG. 1 is a perspective view of the oval manway facer when viewed from the outside of the manway in which the machine is to be installed;
[0013] [0013]FIG. 2 is a perspective view of the oval manway facer when viewed from the inside of a oval manway; and
[0014] [0014]FIG. 3 is an exploded perspective view of the oval manway facer comprising a preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and associated parts thereof Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.
[0016] Referring first to FIG. 1, there is indicated generally by numeral 10 the oval manway facer comprising a preferred embodiment of the present invention. It comprises a housing 12 having a first major surface 14 that is oval-shaped, having its minor access in a vertical direction and its major access in a horizontal direction. The housing 12 has a second major surface 16 best shown in FIG. 2. It too is oval in shape.
[0017] Formed centrally through the housing 12 is an oval-shaped opening 18 and bolted to or otherwise affixed to the first major surface 14 in surrounding relation to the central oval opening 18 is an endless chain 20 whose individual links 22 are spaced by a predetermined pitch. In FIG. 1, the chain 20 is shown as being fastened by connectors 22 that are affixed by screws 24 to the outer wall of the housing comprising the first major surface 14 .
[0018] A plurality of locator jack screws 26 fit into threaded bores formed at the opposed ends of the major and minor axis of the oval-shaped housing 12 . During setup, the screws are used to center the manway facer 10 within the oval opening of the manway to be machined. To further facilitate mounting of the oval manway facer machine 10 in the manway, there is provided a plurality of generally L-shaped locator legs, as at 28 , that fit into rectangular sockets 30 formed through the second major surface 16 of the housing 12 . These locator legs are designed to engage an edge surface of the manway opening to establish the depth of placement and to insure that the facing machine 10 is disposed squarely within the oval manway to be resurfaced.
[0019] With continued reference to FIG. 1, there is shown a motor mount 32 having a face 34 to which a pneumatic, hydraulic or electric motor can be bolted and the shaft of the motor (not shown) passes through the central bore 36 and attached to it is a sprocket wheel having gear teeth whose pitch corresponds to the pitch of the chain 20 .
[0020] The motor mount 32 carries a support arm 38 that extends through the central opening 18 of the housing 12 . As can be seen in the view of FIG. 2, affixed to the free end of the arm 38 carried by the motor mount 32 is a bearing pivot bracket 40 . Also visible in the view of FIG. 2 is a second oval track 42 formed on the second major surface 16 and that surrounds the central opening 18 . This track is preferably formed in the housing by milling first and second concentric grooves separated by a central ridge 44 therebetween. As will be explained in greater detail when the exploded view of FIG. 3 is described, the bearing pivot bracket 40 secured to the arm 38 carries a pair of Vee-grooved rollers that cooperate with the track 42 to effectively clamp the motor mount 32 with its arm 38 to the housing 12 while allowing the motor mount to orbit the first track defined by the endless chain 20 as the sprocket wheel on the motor's shaft is driven.
[0021] With reference again to FIG. 2, pivotally mounted to the bearing pivot bracket 40 is a manway pivot link member 46 , the pivot axis being about a bolt on which the nut 48 is fastened.
[0022] Affixed to the manway pivot link 46 is a tool slide assembly that includes a tool block 52 that is adapted to slide in the radial direction relative to a slide member 54 , which in turn, is pivotally secured to the manway pivot link 46 . As will be explained further herein below, a cam member 56 having a roller 58 thereon cooperates with the wall 59 defining the central opening 18 of the housing and operates to incrementally displace the tool block 52 carrying the cutting tool (not shown) in a radial direction each time the roller 58 engages a tripper pin 60 on wall 59 in the course of orbital travel of the roller.
[0023] Referring again to FIG. 1, identified by numeral 62 is a manually actuable pull knob that is used to selectively engage and disengage the cam 56 to thereby allow or inhibit axial displacement of the tool block and cutting tool relative to the slide 54 . The way in which this is accomplished is described below.
[0024] Now that the general construction of the oval manway facer machine of the present invention has been described, consideration will next be given to the details of implementation and, in this regard, reference will be made to the exploded perspective view of FIG. 3. Starting from the right in the drawing and proceeding towards the left, the motor mount 32 is illustrated as having a central, generally semi-circular opening 64 whose diameter accommodates the sprocket 66 which is keyed to the shaft of the drive motor (not shown). A cover plate 68 bolts to the motor mount 32 to enclose the sprocket wheel, except for a portion thereof that extends down below the confines of the motor mount 32 to engage the endless chain 20 . The arm 38 has one end 70 thereof fitted into a slot 72 of the motor mount 32 and fastened to it by bolts (not shown) passing through slots as at 74 .
[0025] When the sprocket 66 is in engagement with the endless chain 20 the free end 76 of the arm 38 extends through the central opening 18 of the housing member 12 and is secured to the bearing pivot bracket 40 by bolts (not shown) passing through the bores 78 formed in the link 40 .
[0026] Secured to the link 40 by a stationary bushing 80 and a rotatable bushing 82 are Vee bearings 84 and 86 , respectively. The bushing 82 is rotatable about a hex bolt 88 that threadingly fits into a threaded bore 90 formed in the bearing pivot bracket 40 . The spacing between Vee bearings 84 and 86 is such that they capture the track 44 therebetween.
[0027] The manway pivot link 46 is pivotally secured to the bearing pivot bracket 40 using a bolt 92 that passes through a bore 94 formed in a cylindrical stub 96 that is a part of the bracket 40 and, thence, through a thrust washer 98 , a thrust bearing 100 , another thrust washer 102 , needle roller bearing 104 , a further thrust washer 106 , a thrust bearing 108 and thrust washer 110 . This assembly is held in place by a flat washer 112 and the nut 48 .
[0028] The manway pivot link 46 has a generally triangular ear 114 extending from one end of its body and the ear has a threaded bore 116 for receiving a bolt (not shown) that is made to pass through a slide link bushing 118 that fits into a circular bore 120 formed through the manway facer slide 54 , which allows limited pivoting of the slide 54 relative to the pivot link 46 .
[0029] Affixed to the back surface of the slide 54 is a pair of Vee bearings 122 and 124 that are journaled for rotation by a stationary bushing 126 and a rotatable bushing 128 , respectively. The stationary bushing 126 is held in place by a bolt 130 while the rotatable bushing is held by a bolt 132 . As with the bearings 84 and 86 , the bearings 122 and 124 also engage the track 44 therebetween to constrain the tool slide 54 as it is made to orbit the track as the drive motor drives the sprocket 66 along the chain 20 .
[0030] The tool slide assembly 50 shown in FIG. 2 comprises the aforementioned tool slide 54 to which is slidingly affixed the tool block 52 . Specifically, the tool slide includes a dove-tail projection 134 adapted to fit into a dove-tail groove 136 formed in the tool block 52 . A gib 138 , also having a Vee groove, is adapted to mate with the dove-tail projection 140 when bolted to the inside of a flange 142 formed on the tool block. This arrangement allows the tool block 52 to move reciprocally relative to the slide block 54 . The reciprocal movement is imparted by means of a threaded feed screw 144 that passes through a threaded bore in a feed nut 146 that fits into an appropriately sized opening in the manway facer slide 54 .
[0031] Rotation is imparted to the lead screw 144 through a Torrington clutch 148 that is captured in the bore 150 of the cam 56 between cam bushings 152 and 154 . The Torrington clutch functions as a one-way ratchet on the shaft of the feed screw 144 . The cam roller 58 screws into a threaded bore 156 of the cam 56 .
[0032] Controlling the locked and unlocked state of the cam 56 is a control assembly, including a connector lock link 158 that is pinned to the cam lock 160 used to lock the cam 56 . When the cam 56 is locked, the feed screw 144 will not advance the tool in the block 52 radial direction. The other end of the connector lock link 158 is pinned to the push lock rod 162 , which slides in a cam top plate 164 . A compression spring 166 slides over the push lock rod 162 . The cam lock handle 62 slides over the other end of the push lock rod 162 and is held on by the lock nut 168 . Pulling the handle 62 and turning it a quarter turn compresses the spring 166 and holds the cam lock 160 away from the cam 56 . Turning the handle another quarter of a turn allows the spring 166 to push the cam lock 160 forward, which will lock the cam 56 the next time it is tripped by the tripper pin 60 disposed in the path of travel of the cam roller 58 .
[0033] A tension spring 170 fits in the clevis end of the cam 56 and is held by a dowel pin 172 . Another dowel pin 174 goes through the loop on the other end of the spring 170 , the dowel pin 174 being captured between a cam keeper plate 176 and a cam top plate 178 . The clevis end of the cam lock 160 is pinned to the connector lock link 158 . The opposite end of the connector lock link 158 is pinned to the clevis end 180 of the push lock rod 162 by a dowel pin 182 . The spring 170 functions to pull the cam 56 back after it strikes and passes over the tripper pin 60 . The cam 56 , its clutch 148 , along with its bushings 152 and 154 as well as the manually operated cam lock lever assembly are captured between the cam feed bracket 176 and the cam top plate 164 when these two parts are bolted to each other a cotter pin 184 passes through a bore that extends transversely through the bottom of the lead screw 144 .
[0034] The tool bit is adapted to be captured and held in the tool holder 186 . Part 186 has a key way 188 formed in the back surface thereof for receiving a ramp like protrusion on part 190 . The part 190 is secured in a cavity 192 of the tool block 52 by means of dowel pins 194 and 196 the ends of which pass through elongated slots in the tool holder 186 as well as through the elongated slots as at 198 on the tool block. A depth-of-cut adjustment screw 198 passes through a bore in the side face of the tool block 52 and into a threaded bore 200 of the ramp member 190 . The adjustment screw 198 is captured by a bushing 202 that is bolted to the side surface of the tool block 52 . When the hex nut end of the adjustment screw 198 is rotated it moves the wedge member 190 causing displacement of the tool holder 186 along with its cutting bit (not shown).
[0035] Having completely described the constructional features of the oval manway facer comprising a preferred embodiment of the present invention, consideration will next be given to its mode of operation.
[0036] The assembly shown in FIGS. 1 and 2 is brought to the site and the housing 12 is centered in the oval opening of the manway to be refurbished. The centering jack screws 26 and the legs 28 with the depth stop pads 29 are used to center and align the oval manway facer within the central opening of the manway. A motor (not shown) is bolted to the face 34 of the motor mount 32 and its shaft is keyed to the sprocket wheel 66 . When the motor is energized, the sprocket will “walk” around the first track defined by the chain 20 affixed to the first major surface 14 of the housing 12 . As the motor and motor mount orbit the oval housing, the arm 38 carrying tool slide assembly 50 also travels in an elliptical, orbital path with the bearing pivot bracket 40 and the manway pivot link 46 constrained to follow the track 44 on the second major surface 16 of the housing 12 by virtue of the fact that the track is clamped between the Vee bearings 84 , 86 and 122 , 124 . As a result, a tool bit clamped in the tool holder 186 also moves in the orbital elliptical path. Upon each revolution of the assembly around the track, the cam roller 58 will strike and pass over the tripper bar 60 mounted on the wall defining the central oval opening 18 of the housing. Depending upon the positioning of the control lever 62 , the rotation of the cam 56 upon striking the tripper bar 56 will impart a rotation of the feed screw 144 through a predetermined arc. Rotation of the feed screw, in turn, causes a radial displacement of the tool block 45 along the dove-tail guides on the tool slide 54 . The feed rate of the feed screw 144 can be increased by providing more than one tripper bar 60 in the orbital path traversed by the cam roller 58 .
[0037] As mentioned above, rotation of the height adjustment screw 198 is used to vary the depth-of-cut of the cutting tool with respect to the gasket surface of the manway being machined. This axial adjustment of the tool bit is achieved without need to remount the machine in the manway opening.
[0038] In that the cam lock handle 62 extends through the central opening 18 of the housing it is easily accessible to an operator located outside of the vessel on which the manway is disposed. Thus, the radial feed of the cutting tool can be allowed or arrested by the operator. Because of the open central portion of the machine, the operation can readily inspect the surface as it is being machined so that less rework is required.
[0039] While the invention has been described in detail, it is to be understood that various changes and modifications may be made therein without departing from the spirit and scope of the invention, as defined in the appended claims. | A machine tool for re-surfacing gasket seats surrounding elliptical openings in oval manways includes a housing of an oval configuration that is adapted to be mounted in the opening of the manway to be machined. A motor and a tool slide assembly are secured to the motor mount in such a fashion that the tool slide assembly is confined to travel in an oval orbit along a second major surface of the housing. A cam actuated feed screw is appropriately disposed to engage a tripper bar disposed in the path of travel to effect radial displacement of a tool holder and tool bit. A cam locking and unlocking control lever cooperates with the cam and is disposed such that an operator located outside of the vessel on which the manway is disposed can readily control the machining operation. | 8 |
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] The present application contains subject matter related to Singapore Patent Application SG 200603971-3 filed in the Singapore Patent Office on Jun. 15, 2006, the entire contents of which being incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to a magnetic anodized aluminium oxide with high oxidation resistance and to a method of manufacturing a magnetic anodized aluminium oxide and relates particularly, though not exclusively, to such a magnetic anodized aluminium oxide and a method of its manufacture able to resist oxidation in an atmosphere with oxygen, at an elevated temperature.
BACKGROUND TO THE INVENTION
[0003] Oxidation is a serious problem in conventional metallic magnets such as rare earth magnets of niobium-iron-boron and samarium cobalt. Such oxidation is dominated by corrosion that occurs at their surfaces. If no protective coating is provided, oxygen diffuses into the surfaces of such a magnet, causing a metallurgical change in the surface layer. The consequence of oxidation of the surface layer is that the surface layer possesses a lower intrinsic coercivity. The lower coercivity allows the surface layer to be more easily demagnetized. At the same time, the formation of non-magnetic metallic oxides in the surface layer will lead to a reduction in the absolute magnetic flux that can be obtained from the magnet. It has been found that the oxidized surface layer varies as a function of both temperature and time. The higher the temperature or the longer the time, the greater will be the extent of oxidation.
[0004] Recently, electrodeposited cobalt-platinum (CoPt) based alloys have been studied as permanent micromagnets for application in magnetic microsystems. Among these, an alloy of cobalt-platinum-tungsten-phosphorus (CoPtWP) is a material the composition of which allows it to be electrodeposited to a high thickness—more than 20 um being possible—while maintaining the magnetic properties required for application in magnetic microdevices.
[0005] Although the electroplating of magnets is most often a room-temperature process, the fabrication of microdevices often involves elevated temperature steps such as, for example, wafer-level bonding. These are most often in air. Therefore, the thermomagnetic properties and oxidation resistance of the electrodeposited micromagnets are of importance for the application of such micromagnets. CoPtWP alloys suffer magnetic degradation due to oxidation after being subjected to temperature treatment in air. The formation of non-magnetic metallic oxides is an obstacle to the integration of electroplated magnets in microdevices as it reduces the magnetic flux density deliverable from the magnet. For example, the perpendicular remnant magnetization of a 5.4 um thick CoPtWP electroplated film decreases by ˜22% upon thermal treatment at 212° C.
[0006] To be able to achieve success in the application of electroplated magnets in microdevices, the electroplated magnets must be able to resist oxidation at elevated temperatures in air or other oxygen-rich atmosphere.
SUMMARY OF THE INVENTION
[0007] According to a first preferred aspect there is provided a magnetic anodized aluminium oxide comprising a layer of anodized aluminium oxide forming a housing for an array of nanowires of a magnetic material formed in nanopores in the layer of anodized aluminium oxide. The nanowires may have their side walls embedded in the nanopores in the layer of anodized aluminium oxide for preventing oxidation of the side walls.
[0008] According to a second preferred aspect there is provided a magnetic anodized aluminium oxide comprising a layer of anodized aluminium oxide with nanowires of a magnetic material having their side walls embedded in nanopores in the layer of anodized aluminium oxide for preventing oxidation of the side walls. The nanowires may be in an array formed in micropores in the layer of anodized aluminium oxide.
[0009] For both aspects the magnetic anodized aluminium oxide may further comprise a seed layer of an electrically conductive material. The nanopores may be of a diameter of 70 nanometers, and the layer of anodized aluminium oxide may be of a thickness of 60 microns.
[0010] According to a third preferred aspect there is provided a method of forming a layer of magnetic anodized aluminum oxide, the method comprising electroplating a magnetic material into a layer of anodized aluminum oxide in an electrochemical bath.
[0011] The electrochemical bath may have a composition comprising: Co 2+ ions in the range 0.001 to 0.5 mol/liter, PtCl 6 2− ions in the range 0.001 to 0.5 mol/liter, WO 4 2− ions in the range 0.001 to 0.5 mol/liter, and HPHO 3 − ions in the range 0.001 to 0.5 mol/liter; and may have a pH in the range 4.0 to 5.0.
[0012] Electroplating may be carried out at a current density in the range 1 to 1000 mA/cm 2 . The layer of magnetic anodized aluminum oxide may be subjected to annealing in air in the range 100° C. to 400° C. The electroplating may be into nanopores of the layer of anodized aluminium oxide. The method may further comprise depositing a seed layer of an electrically conductive material before electroplating the magnetic material.
[0013] For all three aspects the magnetic material may be of an alloy containing cobalt in the range 45 to 95 atomic %, platinum in the range 0.5 to 50 atomic %, tungsten in the range 0.5 to 20 atomic %, and phosphorus in the range 0.5 to 10 atomic %.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order that the invention may be fully understood and readily put into practical effect, there shall now be described by way of non-limitative example only preferred embodiments of the present invention, the description being by way of example only, and being with reference to the accompanying drawings.
[0015] In the drawings:
[0016] FIG. 1 is a scanning electron microscope (“SEM”) image showing the top view of an anodized aluminium oxide template;
[0017] FIG. 2 is a SEM image showing a cross-sectional view of the template of FIG. 1 ;
[0018] FIG. 3 is a SEM (back-scattered electron) image showing a cross-sectional view of CoPtWP nanowires embedded in an anodized aluminium oxide substrate;
[0019] FIG. 4 is a schematic diagram showing electroplated nanowires in an anodized aluminium oxide housing to form a magnetic anodized aluminium oxide material;
[0020] FIG. 5 is a graph of hysteresis curves of the material of FIGS. 3 and 4 before and after annealing at 320° C. for 2 hours in air;
[0021] FIG. 6 is a schematic diagram of the same mass of magnetic materials in two different forms: an unprotected planar film, and an array of nanowires within an anodized aluminium oxide housing; and
[0022] FIG. 7 is a plot showing the trend in remnant magnetization Mr and saturation magnetization Ms as a function of annealing time at 320° C. in air for both a plane film and nanowires in anodized aluminium oxide.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0023] As shown in FIG. 4 , an array 10 of magnetic nanowires 14 was embedded in anodized aluminum oxide 12 by electroplating into nanopores 22 in the anodized aluminum oxide 12 to form magnetic anodized aluminum oxide. The nanowires 14 are the hard magnetic phase of an alloy of CoPtWP. The alloy of CoPtWP preferably contains cobalt in the range 45 to 95 atomic %, platinum in the range 0.5 to 50 atomic %, tungsten in the range 0.5 to 20 atomic %, and phosphorus in the range 0.5 to 10 atomic %.
[0024] The housing formed by the anodized aluminum oxide 12 protects the thick, hard, magnetic material of the nanowires 14 against thermal oxidation. Thermal oxidation causes degradation of magnetic performance for applications at an elevated temperature in air. As shown in FIG. 7 , the remnant magnetization, Mr, saturation magnetization, Ms, and squareness, S, in the out-of-plane direction of the magnetic anodized aluminum oxide 12 were unchanged before and after annealing at 320° C. in air and were maintained up to a minimum annealing duration of 10 hours under the same temperature and atmosphere. The initial and final Mr, Ms and S were ˜12 memu, 13 memu and 0.94 respectively.
[0025] Anodized aluminum oxide 12 with about 70 nanometers pore diameter and 60 micron thickness was used as the template for electroplating. Scanning electron microscope (“SEM”) images of the top and cross-sectional views of the anodized aluminum oxide template are shown in FIGS. 1 and 2 .
[0026] One side of the anodized aluminum oxide was sputtered with about 300 nm gold (Au) as a seed layer 16 for electroplating purposes. Another electrically conductive material such as, for example, silver or copper, could be used, if required or desired. Electrodeposition was carried out using a rotating disk electrode (“RDE”) system via a galvanostat/potentiostat. Ag/KCl was used as the reference electrode while pure platinum wire was used as the anode. The composition of the electrolyte solution for electroplating CoPtWP within the nanopores 22 of the anodized aluminum oxide 12 templates is given in Table 1. The solution was adjusted to a pH of 4.5 using NaOH and/or H 2 SO 4 . Electroplating conditions of current density and agitation speed are summarized in Table 1. In consideration of the overall plating area inclusive of the anodized aluminum oxide regions, current density was about 884 mA/cm 2 .
[0000]
TABLE 1
Concentration
Electrochemical Bath Composition
(Co—Pt—W—P)
B(OH) 3
0.4 mol/L
NaCl
0.4 mol/L
CoCl 2 •6H 2 O
0.01 mol/L
Na 2 PtCl 6 •6H 2 O
0.02 mol/L
Na 2 WO 4 •2H 2 O
0.003 mol/L
NaH 2 PO 3 •2.5H 2 O
2.5 g/L
Sodium Dodecyl Sulfate
0.0096 g/L
Saccharin (Sodium based)
1.0 g/L
Current Density
0.25 A
Plated anodized aluminum oxide area
6 mm diameter circle
Agitation (Rotation) Speed
250 rpm
Bath Temperature
Room Temperature
Bath pH
4.5
[0027] During electroplating, CoPtWP nanowires started growing from the bottom of the pores i.e. from the Au seed layer 16 along the nanopore channels 22 of the anodized aluminum oxide. As a result, arrays 10 of CoPtWP nanowires 14 are fabricated and embedded within the pores 22 of the anodized aluminum oxide 12 as shown by the SEM image of the cross-section in FIG. 3 .
[0028] Thermal stability was carried out in ambient atmosphere at 320° C. for 2 hours for each thermal cycle. However, other times and temperatures may be used as required. For example, the temperature may be in the range 100° C. to 400° C. Cycling may be for a total of up to 10 or more hours. Magnetic hysteresis measured in a direction parallel to the nanowires, before and after the first 2 hours of annealing is shown in FIG. 5 . Although the out-of-plane coercivity, Hc, dropped from 4.5 kOe to 3.4 kOe after the first annealing of 2 hours, it maintained at 3.4 kOe up to 10 hours of annealing at 320° C. in air.
[0029] Tables 2 and 3 summarize the changes in out-of-plane absolute saturation magnetization, Ms, absolute remnant magnetization, Mr, coercivity, Hc, and squareness, S, upon annealing with thermal cycles for CoPtWP in the form of a plane film and nanowires housed within anodized aluminium oxide, respectively. It can be observed that Ms and Mr dropped by as much as 84-85% for the case of plane film while there were hardly any changes for the nanowires within an anodized aluminium oxide housing. Although an improvement in Hc was observed initially for the plane film upon annealing, it started to drop beyond ˜6 hours. For the case of nanowires in an anodized aluminium oxide housing, though a drop in Hc was observed after the first thermal cycle, it remained constant for up to 10 hours of annealing.
[0000]
TABLE 2
Annealing Time
Abs. Ms
Abs. Mr
(h)
(memu)
(memu)
Hc (Oe)
S
0
15.25
8.38
3733.27
0.55
2
10.37
7.18
4239.17
0.69
4
7.94
6.24
4318.45
0.79
6
6.05
5.26
4508.73
0.87
8
3.58
2.71
3620.40
0.76
10
2.30
1.33
2313.05
0.58
[0000]
TABLE 3
Annealing Time
Abs. Ms
Abs. Mr
(h)
(memu)
(memu)
Hc (Oe)
S
0
13.11
12.33
4549.37
0.94
2
13.26
12.49
3432.04
0.94
4
13.23
12.39
3414.55
0.94
6
13.28
12.50
3433.39
0.94
8
13.12
12.36
3436.21
0.94
10
12.99
12.21
3446.36
0.94
[0030] As shown in FIG. 6 , typically oxidation of metallic components starts on the surface of materials. In the case of a plane film 18 , the surface-to-volume ratio is high due to the large surface area but a small thickness. For the case of nanowires 10 embedded in an anodized aluminium oxide housing 12 , the exposed area of the magnetic material 10 is only the top surface 20 of each nanowire 10 irregardless of the length of the nanowires 10 . The side walls of the nanowires 10 are embedded in the anodized aluminium oxide 12 and are therefore not exposed to atmospheric oxygen, particularly during processes at elevated temperatures. As the side walls constitute the significantly greater surface area, this significantly reduces the surface area of the nanowires 10 exposed to atmospheric oxygen. In effect, the surface-to-volume ratio of the nanowires 10 in the anodized aluminium oxide 12 is significantly smaller compared to a plane film 18 of the same mass. As a result of the reduced surface area available for oxidation, the magnetic properties of the magnetic nanowires 10 are significantly preserved during temperature treatment.
[0031] As such, a magnetic anodized aluminium oxide with high oxidation resistance is able to resist oxidation in an atmosphere with oxygen, at an elevated temperature in a range such as, for example, 100° C. to 400° C. It may be about 320° C. The resistance to oxidation enables the magnetic component, in the form of electroplated CoPtWP nanowires in an array housed within the anodized aluminium oxide, to substantially maintain their original remnant magnetization. Therefore, they are able to substantially deliver the original absolute magnetic flux even after heat treatment up to about 320° C. in the presence of atmospheric oxygen.
[0032] Whilst there has been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations or modifications in details of design, construction or operation may be made without departing from the present invention. | A magnetic anodized aluminium oxide has a layer of anodized aluminium oxide forming a housing for an array of nanowires of a magnetic material formed in nanopores in the layer of anodized aluminium oxide. The nanowires have their side walls embedded in the nanopores in the layer of anodized aluminium oxide for preventing oxidation of the side walls. A corresponding method is also disclosed. | 8 |
This is a Division of application Ser. No. 08/646,451 filed May 7, 1996 now U.S. Pat. No. 5,698,471.
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a piezoelectric composite substrate structure. More particularly, the invention relates to joining, by wafer bonding, a piezoelectric material and another substrate. The present invention is further directed to a structure comprising a piezoelectric composite substrate.
Piezoelectric materials have been widely used as component materials for electronic devices used in communication equipment, data processing equipment, or other similar equipment. Various piezoelectric materials have also been used as component materials for communication devices. In particular, single crystal piezoelectric materials such as quartz, lithium niobate, lithium tantalate, or similar materials have been widely used for bulk wave devices such as piezoelectric transducers and elastic surface wave devices. In manufacturing these devices, wafer bonding technology and/or anodic bonding technology are employed to yield the desired compact size and yield.
With respect to wafer bonding technology, two substrates, either of the same or different material, are bonded without an intermediate adhesive layer such that adhesion by covalent bonding or ionic bonding between the atoms on the substrate surfaces occurs. Wafer bonding is accomplished by joining two mirror finished substrates and applying heat. anodic bonding is performed by joining two mirror finished substrates and heat treating them while, at the same time, applying a voltage to the interface between the two substrates. Bonding strength depends on the heat treatment temperature. Generally, the higher the heat treatment temperature, the stronger the bonding strength. However, when the treatment temperature becomes too high, adverse effects may occur. For example, if two substrates undergoing wafer bonding or anodic bonding have different thermal expansion rates, the substrates may break or delaminate due to the different thermal expansion coefficients.
Similar problems may occur with piezoelectric composite substrates or piezoelectric devices during manufacturing. For example, the average expansion coefficient of silicon from 25 to 300° C. is 3.4×10 -6 /°C., while that of quartz is 15.2×10 -6 /°C., lithium niobate is 18.3×10 -6 /°C., and lithium tantalate is 19.9×10 -6 /°C. In these piezoelectric materials, the average expansion coefficients are in the x-axis direction of the crystals. Thus, the thermal expansion coefficient of quartz in the x direction is five times that of silicon, and this difference in thermal expansion coefficients may cause damage to the substrate combination.
Japanese laid-open patent Heisei-5-327383 discusses the relationship between the thickness of a quartz substrate and temperature where the substrate is damaged when a quartz substrate and a semiconductor substrate are bonded by wafer bonding. That is, it is reported that the thinner the quartz substrate, the higher the damage temperature, because the stress generated at the bonding portion is reduced. For example, for a large silicon substrate, the damage temperature at which the substrate is damaged is 350° C. when the thickness of the quartz substrate is 80 μm, while the damage temperature at which the substrate is damaged is 450° C. when the thickness of the quartz substrate is 40 μm. The temperature at which damage occurs varies according to the size and configuration of the substrate. Accordingly, the heat treatment temperatures when wafer bonding have to be lower than the temperature at which damage may occur.
Furthermore, single heat treatments may have adverse effects. That is, in wafer bonding, water structuring molecules exist at the bonding interface after initial joining. Thus, there are water structuring molecules at the bonding interface during the adhering step. While, most of the water structuring molecules are removed as the heat treatment temperature rises, some are trapped by surrounding adhesion. As a result, voids are created without adhesion. Thus, there exist at the bonding interface strongly bonded portions and void portions resulting in uneven distribution of thermal stresses. This condition may damage the substrates and cause delamination of the joined substrates.
In the case of ionic bonding, voids may be generated due to gas existing at the bonding interface either from the initial joining or from gas being generated during the heat treatment, thus resulting in the same problems as discussed above. Moreover, while gas can be generated during the bonding processes of the substrates, further heat treatments after the bonding process may also generate additional gas. For example, thermal stress from heating from solder reflowing may generate voids, may damage the substrates, and may cause delamination of the substrates.
To solve these problems according to conventional methods, wafer bonding is accomplished by employing two heat treatments and using thin substrates. That is, substrates are bonded temporarily at a relatively low first temperature, thinned by a mechanical method or chemical etching, and then bonded strongly at a relatively high second temperature to complete wafer bonding. See, for example, Japanese laid-open patents. H5-327383, H4-286310, H-3-97215. More particularly, substrates are bonded temporarily by heat treating at the first temperature at which damage of the substrates does not occur, then thinned by grinding, and finally bonded strongly at a temperature sufficiently high to obtain the desired bonding strength.
However, even these methods cannot prevent the problems of the aforementioned voids and delamination. Moreover, yield tends to become lower in actual manufacturing processes. Since removing water from a central portion of the substrate is difficult compared to the periphery of the substrate, it is difficult to prevent damage caused by the stress generated at the central portion of the substrate. Central water deposits become an ever bigger problem when substrate size is enlarged in order to reduce manufacturing costs.
Even if the damage or delamination of substrates can be avoided, the stress to the substrates may affect the performance characteristics of elements formed on the composite substrate due to insufficient bonding. More specifically, such imperfections affect the temperature-to-frequency characteristics of a piezoelectric device such as a piezoelectric vibrator or a piezoelectric filter. That is, thermal stress experienced by substrates is increased by temperature changes.
Stress caused by different thermal expansion coefficients may also change the crystal structure. When molecule structures are the same but various crystal structures exist, the crystal structures may be changed by pressure or temperature. For example, when quartz is heated up to more than 573° C. under no pressure, the quartz transitions from α-quartz to β-quartz. Other phase transitions besides α-β phase transitions can also be seen. Dauphine twin type phase transitions which occur when stress is applied to quartz is one example. Moreover, a Dauphine twin type phase transition which occurs at high temperature is a nonreversible reaction as reported in Annual Symposium Frequency Control, Vol. 31, page 171 (1977). When an element is formed on a substrate on which these phase transitions have occurred, undesirable characteristics result. More specifically, in the case of a phase transition in AT cut quartz, dependency of frequency characteristics on temperature increases, thus stable operation of piezoelectric elements such as quartz vibrators and quartz filters cannot be realized.
SUMMARY OF THE INVENTION
When substrates having different thermal expansion coefficients are bonded by wafer bonding or anodic bonding, the substrates may experience damage or delamination when heated due to the different thermal expansion rates. Moreover, the crystal structure of the is substrates may be changed by thermal stress. Furthermore, a piezoelectric composite substrate may be distorted by subsequent stress.
Accordingly, it is an object of the present invention to solve the above problems. In particular, the invention overcomes the problems of substrate damage and delamination, crystal structure transition, performance characteristic degradation caused by subsequent stresses or surrounding temperature changes for piezoelectric composite substrates and piezoelectric devices composed of substrates having respective different thermal expansion rates.
To achieve the aforementioned objects, a method of manufacturing a composite substrate of the invention comprises the steps of mirror finishing at least one of the surfaces of a first substrate, mirror finishing at least one of the surfaces of a second substrate having a thermal expansion coefficient different from that of the first substrate, making the principal surface of the first substrate and the principal surface of the second substrate hydrophilic, abutting the principal surface of the first substrate and the principal surface of the second substrate on each other, applying a first heat treatment to the abutted substrates at a temperature lower than the temperature where bonding of the first substrate and the second substrate starts, in order to remove water remaining between the first substrate and the second substrate, dividing the joined substrates into at least two pieces while maintaining the joined state, and applying a second heat treatment to the at least two pieces at a temperature where bonding of the first substrate and the second substrate occurs.
Another method of manufacturing a composite substrate according to the present invention comprises the steps of mirror finishing at least one of the surfaces of a first substrate, mirror finishing at least one of the surfaces of a second substrate having a thermal expansion coefficient different from that of the first substrate, making the principal surface of the first substrate and the principal surface of the second substrate hydrophilic, abutting the principal surface of the first substrate on the principal surface of the second substrate, applying a first heat treatment to the abutted substrates at a temperature lower than the temperature where bonding of the first substrate and the second substrate starts, in order to remove water remaining between the first substrate and the second substrate, cutting a part of the second substrate to a depth sufficient to reach the first substrate after the first heat treatment step, and applying a second heat treatment to the joined substrates at a temperature where bonding of the first substrate and the second substrate occurs.
According to the present invention, even if substrates having respective different thermal expansion coefficients are joined by wafer bonding, the stress at the bonding portion can be remarkably reduced, and as a result, the problem of substrate damage and delamination can be prevented, and mass-production of the composite substrate can be enhanced. Moreover, since the stress in the substrates is effectively reduced, degradation of performance characteristics of an element formed on the substrates due to the stress can be avoided. Furthermore, with respect to a quartz substrate, phase transition stimulated by stress can be avoided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a-c show a manufacturing method of a piezoelectric composite substrate in accordance with a first embodiment of the present invention.
FIGS. 2a-d show a manufacturing method of a piezoelectric composite substrate in accordance with a second embodiment of the present invention.
FIGS. 3a-d show a manufacturing method of a piezoelectric composite substrate in accordance with a third embodiment of the present invention.
FIGS. 4a-d show a manufacturing method of a piezoelectric composite substrate in accordance with a fourth embodiment of the present invention.
FIGS. 5a-b show structural views of a piezoelectric composite substrate of a ninth through a twelfth embodiment of the present invention, where FIG. 5a is a perspective view and FIG. 5b is a plan view.
FIGS. 6a-b show structural views of a piezoelectric oscillator using the piezoelectric composite substrate in accordance with a ninth through a twelfth embodiment of the present invention, where FIG. 6a is a perspective view and FIG. 6b is a plan view.
FIGS. 7a-b show structural views of a piezoelectric composite substrate in accordance with a tenth embodiment of the present invention, where FIG. 7a is a perspective view and FIG. 7b is a cross-sectional view.
FIGS. 8a-b show structural views of a piezoelectric oscillator using the piezoelectric composite substrate in accordance with a modification of the tenth embodiment of the present invention, where FIG. 8a is a perspective view and FIG. 8b is a cross-sectional view.
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1
A first embodiment of the manufacturing method of the present invention will be illustrated with reference to FIG. 1. FIG. 1(a) is a sectional view of a substrate 1 and a substrate 2. In this first embodiment substrate 1 is quartz and substrate 2 is silicon. Silicon substrate 2 is, for example, 12×12 mm in size and 450 μm thick, and quartz substrate 1 is, for example, 12×12 mm in size and 80 μm thick.
First, surfaces of quartz substrate 1 and silicon substrate 2 are mirror ground, and their respective surface layers are removed by a hydrofluoric acid system. Next, quartz substrate 1 and silicon substrate 2 are dipped in a mixed solution of ammonia, hydrogen peroxide, and deionized water to make the principal surfaces thereof hydrophilic. Thereafter, substrates 1, 2 are thoroughly washed by deionized water. As a result of the hydrophilic treatment, the surfaces of the substrates are terminated with hydroxyl groups. Next, the mirror ground surfaces of the two substrates 1, 2 are abutted, and the two are adhered to each other by Van der Waals force.
Next, a first heat treatment is applied at 150° C., for 5 hours to remove excess water remaining on or within the adhered substrates 1, 2. The first heat treatment is generally applied at a temperature in a range between 100-300° C., and is applied for several minutes up to tens of hours. Preferably the temperature range is between 100-200° C. and is applied for at least one hour. Under these conditions bonding of the substrates 1, 2 does not occur. While heating is necessary to remove excess water, ionic bonding or covalent bonding should be avoided, since stress would otherwise be experienced at the bonding interface 21 and this may cause damage to the substrates 1, 2. In other words, the first heat treatment temperature should be applied at a temperature at which the adhesive force by Van der Waals force is maintained, ionic bonding or covalent bonding does not occur, but water can nevertheless be removed. More specifically, the two substrates 1, 2 after the first heat treatment, should be separable from each other by mechanical means.
Next, a second heat treatment is applied at a temperature of 300° C. for 3 hours. This second heat treatment removes water at the bonding interface 21 and bonds the substrates 1, 2 along a bonding interface 22 by ionic bonds or covalent bonds. In the case of a quartz substrate 1 and a silicon substrate 2, the second heat treatment is performed at a temperature higher than the first heat treatment temperature and lower than the phase transition temperature of quartz, namely 573° C. This treatment should last for several minutes to tens of hours, and preferably at a temperature between 200-500° C.
FIG. 1(b) shows a piezoelectric composite substrate after the first heat treatment. The two substrates 1, 2 are adhered at bonding interface 21 mainly by hydroxyl groups, or water structuring molecules. Here, the water structuring molecules are molecules based on water molecules on which various atoms or molecules existing at the interface are added.
These bonds are relatively weak bonds, and water and gases at the bonding interface of the two substrates 1, 2 can be easily removed. Accordingly, few voids form at the bonding interface 21 of the substrates 1, 2. FIG. 1(c) shows a piezoelectric composite substrate after the second heat treatment. Here, the two substrates 1, 2 are strongly bonded at an atomic level at bonding interface 22 mainly by covalent bonds (siloxane bonds).
The manufacturing method illustrated above can suppress generation of voids, reduce stress, and realize wafer bonding using only heat treatments. That is, the step of thinning a substrate is avoided, thus, resulting in improved manufacturing yield of piezoelectric composite substrates.
By dividing the first heat treatment into a low temperature step and a high temperature step, removal of water and gas from the bonding interface 21 improves further. That is, water removal is more easily achieved not by rapid heating, but by step or slow heating. For example, a low temperature step of the first heat treatment is generally 100-200° C. for several minutes to tens of hours, and preferably 100-180° C. for one hour to tens of hours. The high temperature step is generally higher than the low temperature step and under 300° C. for several minutes to tens of hours, and preferably higher than the low temperature step and under 200° C. for one hour to tens of hours.
In the above embodiment, single crystal piezoelectric materials such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate 1. Semiconductor substrates such as gallium arsenide, indium phosphate, glass, or other piezoelectric substrates having different thermal expansion coefficients from that of piezoelectric substrate 1 can be used as the substrate 2 to be bonded with the piezoelectric substrate 1.
When wafer bonding the same kind of piezoelectric substrates with each other, substrates having crystal anisotropy may be bonded with their crystal directions out of alignment, and the stress problems as with different types of substrates may occur. This problem is also solved by the present invention.
Embodiment 2
A second embodiment of the manufacturing method of the present invention will be illustrated referring to FIG. 2. As shown in FIG. 2a, the substrate materials 1, 2 and configurations are the same as in embodiment 1. Furthermore, the processes of embodiment 1 through the layering process are performed. Then, a first heat treatment is applied at a temperature of 250° C. for 5 hours. In FIG. 2b, the heat treatment temperature is a little higher than that of embodiment 1 to enhance bonding strength in order to prevent delamination during a subsequent dicing process. During the dicing step (FIG. 2c), the piezoelectric composite substrate 1, 2 is cut into 3×3 mm pieces by a dicing saw. A second heat treatment is then applied at a temperature of 350° C. for 3 hours to form bonding interface 22. FIG. 2d shows the piezoelectric composite substrates after the second heat treatment.
In the present embodiment, since the joined piezoelectric composite substrate 1, 2 is cut into small pieces after the first heat treatment to reduce bonding area per piece, water structuring molecules and gases remaining at the bonding interface 21 are easily removed during the second heat treatment. Accordingly, thermal stress unevenly generated during the second heat treatment is further reduced compared to the manufacturing method of the first embodiment.
The above-described method is very effective when substrates 1, 2 are large because water remaining at a central portion of the substrates 1, 2 can be thoroughly removed.
The manufacturing method illustrated above can suppress generation of voids, reduce stress, and realize wafer bonding using only heat treatments. That is, the step of thinning the substrate is avoided, thus, resulting in improved manufacturing yield of piezoelectric composite substrates, especially, when the substrate 1, 2 size is large.
The first heat treatment can be divided into a low temperature step and a high temperature step, as in embodiment 1.
In the above embodiment, single crystal piezoelectric material such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate. Semiconductor substrates such as of gallium arsenide, indium phosphate, glass, or other piezoelectric substrates having different thermal expansion coefficients from that of the piezoelectric substrate 1 can be used as the substrate 2 to be bonded with the piezoelectric substrate 1.
Embodiment 3
A third embodiment of the manufacturing method of the present invention will be illustrated referring to FIG. 3. As shown in FIG. 3a, the substrate materials 1, 2 and configurations are the same as in embodiment 1. Similar to embodiment 2, the processes through the abutting process are performed. Then, a first heat treatment is applied at 250° C. for 5 hours. Next as shown in FIG. 3c, a part of silicon substrate 2 is removed from the surface opposite of the bonding interface 21 by etching in a hydrofluoric acid system. Then a second heat treatment is applied at a temperature of 350° C. for 3 hours.
During the first heat treatment of the present embodiment, water and gases are easily removed from the bonding interface 21, and the piezoelectric composite substrate 1, 2 is temporarily bonded for the etching process of silicon substrate 2. Since the bonding area of the piezoelectric composite substrate is reduced, water structuring molecules and gas are easily removed from the bonding interface 21.
The manufacturing method illustrated above can suppress generation of voids, reduce stress, and realize wafer bonding, thus resulting in improved manufacturing yield of piezoelectric composite substrates, especially, when the joined substrates 1, 2 are large.
The first heat treatment can be divided into a low temperature step and a high temperature step, as in embodiment 1.
In the above embodiment, single crystal piezoelectric material such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate 1. Semiconductor substrates such as gallium arsenide, indium phosphate, glass, or other piezoelectric substrates having different thermal expansion coefficients from that of the piezoelectric substrate 1 can be used as the substrate 2 to be bonded with the piezoelectric substrate 1.
Embodiment 4
A fourth embodiment of the manufacturing method of the present invention will next be explained with reference again to FIG. 1. In the present embodiment, substrate 2 is glass and is used instead of silicon. To simplify the explanation, an example using a glass substrate in only the case of embodiment 1 is illustrated here. However, when a glass substrate 2 is used in the case of embodiments 2 or 3, the same effect as shown in embodiments 2 and 3, namely reducing stress at the central portion of the substrate, can be obtained.
In the present embodiment, the following advantage can be obtained by using a glass substrate 2. A thermal expansion coefficient of a glass substrate can be changed by adding an alkali component such as sodium hydroxide. By bringing the thermal expansion coefficient of the glass close to that of quartz, the second heat treatment temperature can be increased and the piezoelectric composite substrate 1, 2 can be strongly bonded and manufactured with a high yield. Also, glass material is inexpensive. Therefore, the manufacturing cost of piezoelectric composite substrates can be reduced.
In the present embodiment, quartz substrate 1 is 12×12 mm in size, and 80 μm thick. The glass substrate 2 is 12×12 mm in size, and 400 μm thick. The thermal expansion coefficient of the glass substrate 2 is 14×10 -6 /°C.
The manufacturing method of the fourth embodiment is as follows. First, the surfaces of the glass substrate 2 and the quartz substrate 1 are mirror ground and their respective surface layers are removed by a hydrofluoric acid system etching solution. Next, the glass substrate 2 and the quartz substrate 1 are dipped into a mixed solution of ammonia, hydrogen peroxide, and deionized water to make the principal surfaces thereof hydrophilic. Thereafter, substrates 1, 2 are washed by deionized water. As a result of the hydrophilic treatment, the surfaces of the substrates 1, 2 are terminated with hydroxyl groups. Next, mirror ground surfaces of the two substrates are abutted, and the two are adhered to each other by Van der Waals force.
Next, a first heat treatment is applied under the same conditions as embodiment 1.
Next, a second heat treatment is applied at a temperature of 300° C. for 3 hours. This second heat treatment removes water at the bonding interface 21 and bonds the substrates 1, 2 along a bonding interface 22 by ionic bonds or covalent bonds. The second heat treatment is applied at a higher temperature than that of the first heat treatment.
The piezoelectric composite substrate 1, 2 after the first heat treatment, is joined at the bonding interface 21 mainly by hydroxyl groups or water structuring molecules as discussed earlier. These bonds are relatively weak and therefore, water and gases at the bonding interface 21 of substrates 1, 2 can be more easily removed. Accordingly, few voids form at the bonding interface 22 of the substrates 1, 2 after the second heat treatment. As a result, the two substrates 1, 2 are strongly bonded at an atomic level at bonding interface 22 mainly by covalent bonds (siloxane bonds).
The first heat treatment can be divided into a low temperature step and high a temperature step, as in embodiment 1.
In the above embodiment, single crystal piezoelectric material such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate 1.
Embodiment 5
A fifth embodiment of the manufacturing method of the present invention will be explained again with reference to FIG. 1. Substrates used here are a lithium niobate substrate 1 and a silicon substrate 2. To simplify the explanation, an example using a lithium niobate substrate in only the case of embodiment 1 is illustrated here. However, when a lithium niobate substrate 1 is used in the case of embodiment 2 or 3, the same effect as shown in embodiments 2 or 3, namely reducing stress at the central portion of the substrate, can be obtained.
In the present embodiment, the silicon substrate 2 is, for example, 12×12 mm in size and 450 μm thick, and lithium niobate substrate 1 is, for example, 12×12 mm in size and 80 μm thick.
Similar to embodiment 1, the processes through the abutting process of the two substrates 1, 2 are performed. Then, a first heat treatment is applied at a temperature of 250° C. for 5 hours. The first heat treatment is generally applied at a temperature of 100-300° C. for several minutes to tens of hours, and preferably at 100-200° C. for at least one hour. Under these conditions bonding of the substrates 1, 2 does not occur.
A second heat treatment is applied at a temperature of 350° C. for 3 hours. In the case of the lithium niobate substrate 1 and silicon substrate 2, the second heat treatment is generally applied at 200-1000° C. for several minutes to tens of hours, and preferably at a temperature of 250-400° C. The latter temperature range is desirable because, bonding of silicon and lithium niobate starts at 250° C., and the substrates 1, 2 may be damaged at temperature higher than 400° C.
Piezoelectric material is very easily broken depending on its component materials and cut angle, so it may be damaged by uneven thermal stress even during the weak bonding stage. However, in the case of quartz, the phase transition temperature is considerably higher than its damage temperature, and therefore, it is not necessary to determine a maximum temperature of the second heat treatment with regard to the phase transition temperature.
Since the first heat treatment temperature is low, the two substrates 1, 2 are bonded weakly. Water and other gases are easily removed from the bonding interface 21. Thus, few voids form at the bonding interface 21 of the substrates 1, 2 and there is little variation of bonding speed at the surface. As a result, the substrates 1, 2 are not damaged from stress concentration. After the second thermal heat treatment, the piezoelectric composite substrate is strongly bonded at the atomic level at the bonding interface 22.
The first heat treatment can be divided into a low temperature step and a high temperature step, as in embodiment 1.
Embodiment 6
A sixth embodiment of the manufacturing method of the present invention will be illustrated again with reference to FIG. 1. In this embodiment substrate 1 is quartz and substrate 2 is silicon. For simplicity of illustration, the same method as in embodiment 1 is illustrated. However, when the present embodiment is applied to the methods of embodiments 2 or 3, the same effect as shown in those embodiments, namely reducing stress at the central portion of the substrate, can be obtained.
In the present embodiment, the quartz substrate 1 is, for example, 10×10 mm in size and 56 μm thick, and the silicon substrate 2 is, for example, 10×10 mm in size and 450 μm thick.
First, the quartz substrate 1 and silicon substrate 2 are mirror ground and etched by an etching solution of a hydrofluoric acid system etching solution to remove their respective surface layers. Next, the quartz substrate 1 and the silicon substrate 2 are dipped into a mixed solution of ammonia, hydrogen peroxide, and deionized water to make the principal surfaces thereof hydrophilic. Thereafter the substrates 1, 2 are washed thoroughly with deionized water.
As a result of the hydrophilic treatment, the surface of each substrate is terminated by hydroxyl groups. Next, the mirror ground surfaces of the two substrates 1, 2 are abutted, and are then adhered to one another by Van der Waals force.
Next, a first heat treatment is applied at a temperature of 150° C., for 5 hours to remove excess water remaining on or within the substrates 1, 2. The first heat treatment is generally applied at a temperature in a range between 100-300° C., for several minutes to tens of hours, and preferably in a temperature range between 100-200° C. for one hour to tens of hours. While some heating is necessary to remove excess water, ionic bonding or covalent bonding should be avoided since, stress will be experienced at the interface 21 and this may cause damage to the substrates 1, 2. In other words, the first heat treatment temperature should be a temperature at which the adhesive force by Van der Waals force is maintained, ionic bonding or covalent bonding does not occur, but water can nevertheless be removed. More specifically, the two substrates after the first heat treatment, should be separable from mechanical my a mechanical means.
Next, a second heat treatment is applied at a temperature of 250° C., for 3 hours. Here, as illustrated in embodiment 1 in the case of quartz, the temperature of the first heat treatment should be under the α-β phase transition temperature, namely 573° C. However, phase transition can occur at a temperature lower than 573° C. when stress caused by bonding is experienced by the substrates 1, 2. Accordingly, the temperature is reduced by 50° C. compared to the case of embodiment 1 in order to prevent the aforementioned phase transition problem.
In this embodiment after the first heat treatment the two substrates 1, 2 are adhered to one another mainly by hydrogen bonds, and crystal structure transition, due to phase transition of the quartz substrate 1, is not experienced.
Water molecules and gas are easily removed from the bonding interface 21 during the first heat treatment, and water structuring molecules and gas spread uniformly in the interface 21. Thus, uneven thermal stress applied to the quartz substrate 1 is largely decreased. Accordingly, there is neither stress concentration nor phase transition of the quartz substrate 1.
As a result of the first heat treatment, thermal stresses in the bonding interface 21 are generated nearly uniformly during the second heat treatment such that phase transition of the quartz substrate 1 does not occur.
The manufacturing method of wafer bonding illustrated above can suppress the generation of voids during the heat treatments and thereby reduce stress, using only heat treatments. That is, the step of thinning the substrate is avoided, resulting in improved manufacturing yield of piezoelectric composite substrates. Also, phase transition of the piezoelectric substrate can be prevented and a piezoelectric composite substrate of desired characteristics can be manufactured.
The first heat treatment can be divided into a low temperature step and a high temperature step, as in embodiment 1.
In the above embodiment, single crystal piezoelectric materials such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate 1. Semiconductor substrates such as of gallium arsenide, indium phosphate, glass, or other piezoelectric material having a different thermal expansion coefficients from that of the piezoelectric substrate 1 can be used as substrate 2 to be bonded with the piezoelectric substrate 1.
Embodiment 7
A seventh embodiment of the manufacturing method of the present invention will next be explained, again with reference to FIG. 1. In the present embodiment, substrate 1 is quartz and a substrate 2 is glass. For simplicity of explanation, only the method of embodiment 1 is illustrated. However, by using the method of embodiments 2 or 3 with the present embodiment, the same effect as shown in those embodiments, namely reducing stress at a central portion of the substrates 1, 2 can be obtained.
In the present embodiment, glass is used instead of silicon for substrate 2. The thermal expansion coefficient of glass can be changed by varying its component materials. Thus a thermal expansion coefficient close to that of a piezoelectric material to which the glass will be bonded can be selected. Accordingly, piezoelectric composite substrates with strong bonds can be manufactured with good yield rates. Moreover, glass is inexpensive. Thus, when used as a supporting substrate, manufacturing costs are reduced. The quartz substrate 1 is 12×12 mm in size, and 80 μm thick, and the glass substrate 2 is 12×12 mm in size, 400 μm thick. The thermal expansion coefficient of the glass substrate 2 is 10×10 -6 /°C.
After mirror grinding, washing, and hydrophilic treatment, the substrates 1, 2 are abutted. The first heat treatment is applied at a temperature of 150° C. for 5 hours and is generally applied at a temperature range from 90-350° C. and preferably 150-300° C.
Then, the second heat treatment is applied at a temperature of 250° C. for 3 hours. As discussed in embodiment 1 in the case of a quartz substrate 1, the second heat treatment temperature can be, theoretically, up to 573° C., the phase transition temperature of quartz. However, when the stress caused by bonding is experienced by the substrate, the phase transition occurs at a temperature lower than 573° C. Accordingly, the second heat treatment temperature of the present embodiment is 50° C. lower than that of embodiment 1 in order to avoid the aforementioned phase transition problem. The second heat treatment is generally applied, therefore, in a temperature range from 100-573° C., and preferably 250-573° C.
When using a glass substrate 2 which has the advantage of an adjustable thermal expansion rate, the manufacturing method illustrated above can realize wafer bonding, while suppressing the generation of voids and reducing stress, using only heat treatments. That is, the step of thinning the substrate is avoided, resulting in improved manufacturing yields of piezoelectric composite substrates. Also the phase transition of piezoelectric composite substrates can be prevented, and piezoelectric composite substrates with particular performance characteristics can be manufactured. Single crystal piezoelectric materials such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can also be used as the piezoelectric substrate 1.
Embodiment 8
FIG. 4 shows an eighth embodiment of the manufacturing method of the present invention. In FIG. 4a, substrate 1 is quartz, and substrate 2 is silicon. Here, an integrated circuit for signal processing can be formed on the silicon substrate 2. Since wafer bonding can be applied by low temperature heat treatments, the heat treatments do not damage the characteristics of the integrated circuit.
After mirror grinding, washing, and hydrophilic treatment of the substrates 1, 2 similar to the method described in embodiment 1, the substrates 1, 2 are abutted. A first heat treatment is applied at a temperature of 180° C. for 5 hours (FIG. 4b). The first heat treatment is generally applied at a temperature range from 100-300° C., and preferably 100-200° C. at which temperatures substrate bonding does not occur. Then, as shown in FIG. 4c, part of the silicon substrate 2 is removed by an etching solution of hydrofluoric acid system. Incidentally, in actual piezoelectric elements, a part of the substrate where a transducer of piezoelectric device is formed must be removed.
Next, a second heat treatment is applied at a temperature of 380° C. for 3 hours, which results in the structure shown in FIG. 4c. In the case of a quartz substrate 2 and a silicon substrate 1, the second heat treatment is applied at a higher temperature than that of the first heat treatment, but under 573° C. for a period ranging from several minutes to several hours. Preferably the temperature range is 200-500° C.
In the first heat treatment of the present embodiment, temporary bonding of the piezoelectric composite substrate is desired in order to accomplish the etching process of the silicon substrate 2. The second heat treatment is applied to strongly bond the silicon substrate 2 and quartz substrate 1. The portion 5 in FIG. 4d of quartz substrate 1 is strongly bonded at the atomic level.
Here, a portion 5 of quartz substrate 1 at the bonding area and in the vicinity of the bonding area is phase transformed, while a portion 6 of quartz substrate 1, in the area where silicon substrate 2 was removed, is not phase transformed. That is, by the manufacturing method of the present embodiment, even if phase transition occurs at the bonding area in the second heat treatment, the unbonded portion 6 of the substrate used to form a transducer of a piezoelectric device is free from phase transitions. In other words, the second heat treatment can be applied without regard to the phase transition temperature. As a result, devices with desired characteristics can be manufactured using the portion 6 of quartz substrate 1, because that portion is without phase transition. Accordingly, piezoelectric devices can be manufactured with good yields. The manufacturing method illustrated above can realize wafer bonding while suppressing the generation of voids and reducing stress, and result in improved manufacturing yields of piezoelectric composite substrates. Also, the phase transition at a portion affecting the characteristics of piezoelectric device of the composite substrate can be prevented.
Like all other embodiments, the first heat treatment can be divided into a low temperature step and a high temperature step.
Single crystal piezoelectric materials such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate 1 in the present embodiment. Semiconductor substrates such as gallium arsenide, indium phosphate, glass, or other piezoelectric substrates having a different thermal expansion coefficients from that of the piezoelectric substrate 1 can also be used as the substrate 2.
Embodiment 9
FIGS. 5a and 5b show, respectively, a perspective view and a top view of a piezoelectric device using a piezoelectric composite substrate of the present invention. In this embodiment, and those discussed hereinafter, a composite substrate used for a piezoelectric device will be illustrated.
In FIG. 5, a piezoelectric substrate 11 is, for example, an AT cut quartz substrate 4×8 mm in size and 50 μm thick. Semiconductor substrate 12 is, for example, a silicon substrate 8×12 mm in size and 450 μm thick. A bonding area 13 of the piezoelectric substrate 11 and the semiconductor substrate 12 is 4×1 mm in size. An integrated circuit for signal processing may be formed on the silicon substrate 12. Since wafer bonding can be achieved at a low temperature, the heat treatment does not affect the performance characteristics of the integrated circuit. In the present embodiment, bonding area 13 has a rectangular shape with its shorter side aligned with the x axis direction of the AT cut quartz substrate and its longer side aligned with a z' axis, which slants 35° 22' from the z axis of the quartz substrate.
With reference to FIG. 6, excitation electrodes 14a, 14b are provided on upper and lower surfaces of piezoelectric substrate 11 to form a piezoelectric oscillator.
A manufacturing method of a quartz crystal oscillator, one application of the piezoelectric composite substrate of the present embodiment, will next be discussed.
Surfaces of an AT cut quartz substrate 11 and silicon substrate 12 are mirror ground and washed. Also during this step, the AT cut quartz substrate 11 is thinned to a predetermined thickness, for example 50 μm.
Silicon substrate 12 is bore-etched by a hydrofluoric acid system etching solution to form the configuration corresponding to semiconductor substrate 12 in FIG. 6.
Excitation electrodes corresponding to 14a, 14b, in FIG. 6 are formed on the upper and lower surfaces of the AT cut quartz substrate 11 by means of photolithography, vacuum evaporation, or equivalent method. Rear side electrode 14b extends to the upper side of the AT cut quartz substrate 11 by being routed around the edge of the AT cut quartz substrate 11.
The substrates 11, 12 are dipped in a mixed solution of ammonia, hydrogen peroxide, and deionized water to make the principal surfaces thereof hydrophilic, and are thereafter washed with deionized water. As a result of the above treatments, water structuring molecules stick to each substrate surface.
The mirror ground surfaces of the two substrates are abutted and are adhered by Van der Waals force created by the water structuring molecules.
The substrates 11, 12 are temporarily bonded by a first heat treatment at a temperature of 150° C. for 5 hours, and then further heat treated at 350° C. for 2 hours. In the case of an AT cut quartz substrate 11 and silicon substrate 12, a second heat treatment is generally applied at a temperature of 100-573° C. for several minutes to tens of hours. Preferably, the temperature is in the range of 250-500° C.
One of the features of the piezoelectric oscillator of the present invention is that the rectangular configuration of the bonding area 13 associated with the piezoelectric substrate 11 is such that the thermal expansion coefficient in the direction of the longer side of the rectangle is close to that of the semiconductor substrate 12. The thermal expansion coefficients of the AT cut quartz substrate 11 are 15.2×10 -6 /°C. in the x axis direction and 11×10 -6 /°C. in the z' direction described above. Thus, the longer side of the rectangle is arranged to be along the Z' axis direction.
The following observations were made with regard to the quartz oscillator structure described above. The variation of the resonance frequency at a temperature range between 0 and 60° C. was 10 ppm or less. No damage to, or delamination of, the substrates 11, 12 occurred as a result of a heat shock test from room temperature to 260° C. Phase transition of the quartz substrate was observed at the bonding area 13 between the quartz substrate 11 and the silicon substrate 12, while, it was not observed at other areas of the quartz substrate 11. Presence of the phase transition can be confirmed by observing the surface state after etching by a hydrofluoric acid system solution. It can also be confirmed by measuring the face spacing of the crystal lattice by using X ray diffraction. In the structure above, quartz substrate 11 is hardly affected by the thermal stress caused by the different thermal expansion coefficients of the substrates. Therefore, piezoelectric oscillations are not hampered by the thermal stress. Since phase transition does not occur in the quartz substrate portion which constitutes a piezoelectric oscillator, the same frequency to temperature stability as the AT cut quartz itself can be obtained. Also, since the substrates 11, 12 are securely bonded by wafer bonding, the substrates 11, 12 are not damaged if subjected to a heat shock such as solder reflowing.
The same effect can be observed if the corners of the rectangle are curved. Even with other configurations of the substrate 11 in the bonding area 13, the same effect can be expected by orienting the piezoelectric substrate 11 in a direction such that the thermal expansion coefficients of the piezoelectric substrate is closer to that of the semiconductor substrate.
Also by bonding the piezoelectric substrate 11 at both ends, the strength against shock can be enhanced.
Again, the first heat treatment can be divided into a low temperature step and high temperature step, as in the other embodiments.
Single crystal piezoelectric materials such as lithium tantalate or lithium niobate or other mirror grindable piezoelectric materials can be used as the piezoelectric substrate 11 in the present embodiment. Semiconductor substrates such as gallium arsenide, indium phosphate, glass, or other piezoelectric substrates having different thermal expansion coefficients from that of the piezoelectric substrate 11 can also be used as the substrate 12.
Embodiment 10
FIGS. 7a and 7b show, respectively, a top structural view and a sectional structural view of a tenth embodiment of the present invention. In FIG. 7, substrate 11 is a piezoelectric substrate, and in this embodiment is an AT cut quartz 4×8 mm in size and 50 μm thick. Substrate 12 is a semiconductor substrate, which in this case is a silicon substrate 8×12 mm in size and 450 μm thick. Here, an integrated circuit for signal processing may be formed on the silicon substrate 12. Since wafer bonding can be achieved at a low temperature, the heat treatment does not affect the performance characteristics of the integrated circuit.
The piezoelectric substrate 11 and the semiconductor substrate 12 are bonded at a bonding area 13 which is 4×1 mm in size. Bonding area 13 is of a substantial rectangular shape with curved corners. Its shorter side is aligned with the quartz x axis direction and its longer side is aligned with a z' axis which slants 35° 22' from the actual quartz z axis. A constricted part 15 is formed just beyond the bonding area 13 in order to reduce stress.
Also in the present embodiment, excitation electrodes 14a, 14b, are provided on upper and lower surfaces of quartz substrate 11 to form a piezoelectric oscillator as shown in FIG. 8. A quartz oscillator having the above described configuration is advantageous in that the constricted part 15 effectively reduces damage to the quartz caused by thermal stress and the effects to the oscillator due to thermal stress or subsequent stress.
Moreover, in the above structure, quartz substrate 11 is barely affected by thermal stress caused by the different thermal expansion coefficients and as a result, piezoelectric oscillation is not hampered by thermal stress. Since phase transition does not occur beyond the bonding area 13, the same resonant frequency to temperature stability of the AT cut quartz can be obtained in the piezoelectric oscillator. Also, since the substrates 11, 12 are securely bonded by wafer bonding, the substrates 11, 12 are not damaged if subjected to heat shock from solder reflowing, for example.
In the present embodiment, while AT cut quartz was used as a piezoelectric substrate 11, other cut angle quartz substrates can be used in accordance with the application. For instance, lithium niobate or lithium tantalate can be used. These materials have lower frequency-to-temperature change stability, but have higher electromechanical connection coefficients as compared with quartz.
Embodiment 11
An eleventh embodiment of a piezoelectric oscillator in accordance with the present invention is illustrated next with reference again to FIGS. 5 and 6. Substrate 11 in this embodiment is X cut lithium tantalate instead of AT cut quartz and is 4×8 mm in size and 50 μm thick, for example. The shorter side of the bonding area 13 rectangle is aligned with the x axis direction of the x-cut lithium tantalate substrate 11 and its longer side is aligned with the z axis direction of substrate 11.
The difference between the present embodiment and embodiment 9 is that lithium tantalate is used as the piezoelectric substrate 11. Lithium tantalate has a lower frequency-to-temperature change stability, but has a higher electromechanical connection coefficient and lower Q value compared to quartz. Accordingly, lithium tantalate is widely used in voltage controlled oscillators requiring high efficiency and a relatively wide frequency range. Lithium niobate can be used to obtain similar results.
With the structure above, the lithium tantalate substrate 11 is minimally affected by thermal stress caused by the difference in thermal expansion coefficients compared with silicon substrate 12. Thus, piezoelectric oscillations are not hampered by thermal stress. Also since phase transition does not occur beyond the bonding area 13 in the piezoelectric oscillator, the same resonant frequency-to-temperature stability of the lithium tantalate can be obtained. Moreover, since the substrates 11, 12 are securely bonded by wafer bonding, the substrates 11, 12 are not damaged if subjected to heat shock from solder reflowing, for example.
The same effect as described above can be obtained by making the rectangle corners curved. Even with other configurations of the supporting portion, the same effect can be expected by orienting the piezoelectric substrate in a direction such that thermal expansion coefficients of the piezoelectric substrate 11 are closer to that of semiconductor substrate 12.
Also by bonding the piezoelectric substrate 11 at both ends, the strength against shock can be enhanced.
Embodiment 12
A twelfth embodiment of a piezoelectric oscillator in accordance with the present invention is illustrated next again with reference to FIGS. 5 and 6. In this embodiment substrate 11 is an X cut lithium tantalate instead of AT cut quartz, and substrate 12 is glass instead of silicon as in the embodiment 9. X cut lithium tantalate substrate 11 is 4×8 mm in size and 50 μm thick, for example, and the glass substrate 12 is 8×12 mm in size, and 400 μm thick. The glass thermal expansion coefficient is 10×10 -6 /°C. The shorter side of the rectangle of the bonding area 13 is aligned in the x axis direction of the substrate 11 and the longer side is aligned with the z axis direction of the substrate 11.
The difference between the present embodiment and embodiment 11 is that glass is used instead of silicon for the substrate 12. The thermal expansion coefficient of glass can be altered such that its thermal expansion coefficient is close to that of a piezoelectric material to which it is bonded. Also, glass is inexpensive, thereby reducing manufacturing costs.
In the structure described above, the lithium tantalate substrate 11 is minimally affected by thermal stress caused by the difference in thermal expansion coefficients between itself and glass substrate 12. Thus, piezoelectric oscillations are not hampered by thermal stress. Also, since phase transition does not occur beyond the bonding area 13 in the piezoelectric oscillator, the same resonant frequency-to-temperature stability of the lithium tantalate can be obtained. Moreover, since the substrates 11, 12 are securely bonded by wafer bonding, the substrates 11, 12 are not damaged if subjected to heat shock from solder reflowing, for example.
The same effect as described above can be obtained by making the rectangle corners curved. Even with other configurations of the bonding area 13, the same effect can be expected by orienting the piezoelectric substrate in a direction such that the thermal expansion coefficients of piezoelectric substrate are closer to that of semiconductor substrate 12.
Also, by bonding the piezoelectric substrate 11 at both ends, the strength against shock can be enhanced. | A method of manufacturing a composite substrate and the composite substrate manufactured thereby wherein surfaces of first and second substrates having different thermal expansion coefficients are mirror finished and layered on each other. A first heat treatment is applied after which a part of the second substrate is removed to a depth sufficient to expose the first substrate. A final second heat treatment directly bonds the substrates. | 8 |
This application is a Continuation of U.S. patent application Ser. No. 12/899,641, filed on Oct. 10, 2010, and PCT/EP2009/054329 filed Apr. 9, 2009, the disclosures of each incorporated by reference in its entirety.
FIELD OF INVENTION
The present invention relates to a process for the production of nucleic acid encoding a target protein and target protein obtainable thereby, including enzymes such as nucleic acid processing enzymes, and in particular reverse transcriptase.
BACKGROUND OF THE INVENTION
Protein evolution is a known technology for selection and directed evolution of proteins from large libraries. The basic principle of selection is to ensure that there is a linkage between a specific phenotype (protein) and its encoding, genotype. This phenotype-genotype linkage can be realized in three different ways:
covalent linkage such as mRNA display, and to some extent phage display, bacterial display, yeast display etc., non-covalent linkage which use affinity interaction. Examples are ribosome display, CIS display, plasmid display etc., compartmentalization such as in vitro compartmentalisation (IVC), compartmentalized self-replication (CSR), simple bacterial screening, high throughput screening etc.
As indicated in the above paragraph, one example of covalent phenotype-genotype linkage is achieved using mRNA display. As described by Roberts and Szostak (1997) covalent fusions between an mRNA and the peptide or protein that it encodes can be generated by in vitro translation of synthetic mRNAs that carry puromycin, a peptidyl acceptor antibiotic, at their 3′ end.
Non-covalent linkage between phenotype and genotype can be achieved with ribosome display. In ribosome display, an array of RNAs including one or more encoding a target protein is subjected to an in vitro translation system so as to form a non-covalent ternary complex of ribosome, mRNA and protein coupled to tRNA. This array of ternary complexes must be stabilized. Accordingly, each ternary complex formed during in vitro translation uses mRNA lacking a STOP codon at the end. The ternary complexes are further stabilized at low temperature (4° C.) and high concentration of magnesium (50 mM). In the stable complex the linkage between phenotype and genotype is preserved. A selection step follows whereby target protein is selected on the basis of a property of the protein whilst still attached to the ternary complex. Selected ternary complexes may then be disassembled and the mRNA associated with the target protein is amplified by RT-PCR.
In general, ribosome display is successfully applied for the selection of peptides (Mattheakis et al., 1994; Matsuura and Pluckthun, 2003) and proteins (Hanes and Pluckthun, 1997; He and Taussig, 1997; Irving et al., 2001), which bind to different targets. In some cases it is possible to use ribosome display to select for enzymatic activities, performing affinity selection of proteins with suicide inhibitor (Amstutz et al., 2002) or active site ligand (Takahashi et al., 2002).
In in vitro compartmentalization (IVC) phenotype and genotype linkage is realized by in vitro compartmentalization of genes in a water-in-oil emulsion. The number of genes used to prepare the emulsion is calculated such that most of water compartments contain no more than a single gene. The compartmentalized genes are transcribed and translated. The activity of the synthesized proteins is then assessed. Subsequent selection on the basis of protein activity results in amplification of DNA encoding active proteins with desired properties. Water droplets used in most IVC applications are 2-3 μm in size, giving ˜5 femtoliters reaction volume and ˜10 10 water-in-oil compartments (50 μl water phase) per 1 ml of emulsion. The first successful example of IVC selection system was based on target-specific DNA methylation activity (Tawfik and Griffiths, 1998). Genes of Haelll methyltransferase were compartmentalized, transcribed and translated. In vitro synthesized methyltransferase in the presence of a cofactor was able to methylate its own DNA. Based on methylated DNA (reaction product) resistance to digestion with Haelll restriction endonuclease, genes encoding methyltransferase were selected from a 10 7 fold excess of other DNA molecules.
To date many more modifications of IVC have been designed and realized. The easiest way to perform IVC selection is to use DNA-modifying enzymes, in particular DNA-methyltransferases (Lee et al., 2002; Cohen et al., 2004). A similar experimental strategy was applied in order to select for active variants of FokI restriction endonuclease (Doi et al., 2004). Compartmentalized DNA, encoding active restriction endonucleases, was digested and selected by subsequent incorporation of biotin-dUTP and binding to streptavidin beads.
A different IVC selection strategy was applied for evolution of DNA polymerases (Ghadessy et al., 2001; Ghadessy et al., 2004; Ong et al., 2006). This new selection method is based on ‘compartmentalized self-replication’ (CSR) of genes encoding active DNA polymerase. Contrary to usual IVC, where proteins of interest are expressed in situ, CSR is performed by compartmentalization of bacterial cells expressing thermophilic DNA polymerase. Cells resuspended in PCR buffer, supplemented with primers and dNTP's, are emulsified yielding compartments ˜15 μm in size. Each water droplet serves as a separate PCR compartment. During the initial PCR denaturation step the bacterial cells are broken releasing the expressed thermophilic DNA polymerase and its encoding gene into the reaction mixture, allowing self-replication to proceed meanwhile other bacterial proteins are denatured by high temperature.
A modification of IVC is the use of double water-in-oil-in-water emulsions. Water droplets surrounded by an oil layer can be analyzed and sorted in a FACS at a rate of >10 4 variants per second (Bernath et al., 2004; Mastrobattista et al., 2005).
Selection of proteins for binding may also be performed by IVC. A protein of interest expressed in water-in-oil compartments is coupled covalently (Bertschinger and Neri, 2004) or non-covalently (Doi and Yanagawa, 1999; Yonezawa et al., 2003; Sepp and Choo, 2005) to the gene that encodes it.
Other applications of IVC are known where microbeads entrapped into compartments are used as intermediators for protein and gene coupling. Single genes attached to microbeads are transcribed and translated in water droplets. Newly synthesized protein is captured onto the same bead within reaction compartment. After emulsion is broken isolated beads can be used further for affinity selection (Sepp et al., 2002). Emulsions usually are broken using organic solvents (hexane, ether, chloroform), which can also decrease activity of certain enzymes displayed on the beads, limiting the application of this technology. For selection of catalytic activity microbeads can be easily washed, resuspended in different reaction buffer and compartmentalized again by second emulsification step (Griffiths and Tawfik, 2003). However sometimes rigid enzyme-bead-gene complexes (because of sterical hindrance and enzyme mobility limitations) can not fulfil essential reaction requirements and the activity of the attached enzymes may be lower than that of the free enzyme. In addition, such methods are technically complicated since many additional components have to be used (i.e. affinity tags, antibodies, and beads).
The composition of emulsions used in IVC is designed to ensure stability of water compartments and efficient in vitro transcription of mRNA and subsequent translation of target proteins. In vitro evolution has a broad range of targets to be improved. Some proteins and enzymes of interest are robust hard-workers and can be active enough in different buffers, in particular in reaction mixtures used in IVC. However there are many complicated enzymes, which can work only under optimized or specific conditions. In addition to that the first law of in vitro evolution says—“you will evolve what you are selecting for”. That means, an enzyme evolved and optimized in transcription/translation reaction mixture will work well in that particular mixture and most likely will perform much worse in its own buffer. In some cases enzyme working conditions are incompatible with in vitro transcription and translation mixture used for protein expression in compartments. A partial solution is a nano-droplets delivery system (Bernath et al., 2005) used to transport different solutes into emulsion compartments. Even more sophisticated manipulations with water-in-oil compartments can be done employing microfluidics devices. Highly monodisperse single or double emulsions (Thorsen et al., 2001; Okushima et al., 2004) can be prepared at a rate of up to 10000 aqueous droplets per second. Generated water compartments can be transported in microfluidic channels, fused, subdivided and sorted (Song et al., 2003; Link et al., 2006). Nevertheless full buffer exchange in the compartments is still a problem.
Reverse transcriptases are very important commercial enzymes used to synthesize cDNA from an mRNA target. A lot of research has been done in order to improve properties of reverse transcriptases. However no properly working selection system suitable for in vitro evolution of reverse transcriptase was known to date. Almost all improvements are made and mutants of reverse transcriptase selected using high throughput screening and rational design.
Neither ribosome display (RD), nor in vitro compartmentalization (IVC) may be used for selection of fully active reverse transcriptase. Ternary complexes used in ribosome display usually are not stable at higher temperatures required to perform reverse transcriptase selection and as a consequence linkage between phenotype and genotype will be lost. Whilst relatively stable ternary complexes used in ribosome display can be produced using synthetic in vitro translation extract WakoPURE (Matsuura et al., 2007), in vitro translated reverse transcriptase immobilized to ribosome and mRNA will encounter significant steric hindrance during synthesis of full-length cDNA. There is also the possibility that immobilized enzyme will act in trans as well as in cis, which again is incompatible with protein evolution strategy, because the phenotype-genotype linkage will not be preserved.
IVC generally employs DNA as genetic material. In vitro transcription of mRNA and target protein translation is performed in spatially separated emulsified water compartments in the presence of the DNA. In the case of reverse transcriptase in vitro evolution, the presence of coding DNA sequence abolishes the main prerequisite of selection for reverse transcriptase activity—cDNA has to be synthesized de novo. In other words, selection for better reverse transcriptase variants is based on enzyme ability to synthesize their own coding cDNA from mRNA. Newly synthesized cDNA has to be amplified by PCR, therefore cDNA should be the only source of DNA in the reaction. DNA used in IVC selection will amplify together with cDNA canceling basic selection scheme.
More sophisticated variants of in vitro compartmentalization, such as usage of microbeads entrapped in water compartments (Sepp et al., 2002; Griffiths and Tawfik, 2003), allow complete exchange of reaction buffer. In this approach the phenotype-genotype linkage is realized via microbeads yielding a rigid selection unit mRNA-microbead-protein, which, in case of reverse transcriptase selection, again can cause steric hindrance and as a result inefficient cDNA synthesis.
Taq DNA polymerase able to synthesize ˜300 nucleotides long cDNA was selected using modification of phage display technology (Vichier-Guerre et. al, 2006). Although this approach works, it has some shortcomings: 1) not all proteins can be displayed on phages; 2) absolute requirement to use biotin labeled nucleotides for selection; 3) displayed enzyme can work in trans as well as in cis; 4) because of steric hindrance and enzyme mobility limitations phage-enzyme-DNA/RNA complex can interfere with efficient synthesis of cDNA.
The possibility of selection for reverse transcriptase is also mentioned in WO0222869, which is related to the compartmentalized self-replication (CSR) method. CSR technology is used to select thermophilic DNA polymerases, in particular Taq DNA polymerase (Ghadessy et al., 2001; Ghadessy et al., 2004; Ong et al., 2006). Bacterial cells, expressing mutants library of thermophilic DNA polymerase are suspended in PCR mixture and emulsified yielding separate PCR compartments for in vitro selection of more active polymerases.
Real selection for reverse transcriptase activity will be prevented by the presence of bacterial RNases, which remain active at moderate temperatures and will degrade target mRNA. There will also be DNA contamination from non-selected plasmid DNA (released from bacterial cell) as well as the presence of all E. coli enzymes, structural proteins, ribosomes, NTP, RNases, DNases and small molecular weight molecules.
SUMMARY OF THE INVENTION
The present invention aims to provide an improved method of protein evolution which does not suffer from drawbacks of the prior art methods.
Accordingly, in a first aspect, the present invention provides a process for the production of nucleic acid encoding a target protein, which comprises:
(a) providing an array of RNA or DNA molecules including one or more encoding the target protein; (b) generating a target protein from the array to form RNA-protein or DNA-protein complexes in which the RNA or DNA molecule is non-covalently or covalently bound to the complex; (c) separating the complexes into compartments wherein most or all of the compartments contain no more than one complex; (d) subjecting the complexes to reaction conditions which allow target protein activity; and (e) selecting nucleic acid encoding the target protein on the basis of the activity associated therewith,
wherein when the complex is a DNA-protein complex in which the DNA is non-covalently bound, step b) is performed in the absence of separate compartments for each complex.
The present inventors have devised a method which utilizes two distinct types of phenotype-genotype linkage and achieves a new selection system for use in methods of protein evolution within the laboratory.
The new features of the method, described further below, allow it to be applied to an extended range of target proteins in comparison to the methods of the prior art, with increased ease of use and flexibility. In particular, the present invention provides for the first time the possibility of evolving and improving the properties of reverse transcriptase enzymes—one of the most important enzyme groups in the toolbox of molecular biologists.
In one embodiment of this aspect the invention provides a process for the production of nucleic acid encoding a target protein, which comprises:
(a) providing an array of RNA or DNA molecules including one or more encoding the target protein; (b) generating a target protein from the array to form RNA-protein or DNA-protein complexes; (c) separating the complexes into compartments wherein most or all of the compartments contain no more than one complex; (d) subjecting the complexes to reaction conditions which allow target protein activity; and (e) selecting nucleic acid encoding the target protein on the basis of the activity associated therewith,
wherein in the RNA-protein complex the RNA is non-covalently or covalently bound thereto and in the DNA-protein complex the DNA is covalently bound thereto.
In a second embodiment of this aspect the invention provides process for the production of nucleic acid encoding a target protein, which comprises:
(a) providing an array of RNA or DNA molecules including one or more encoding the target protein; (b) generating a target protein from the array to form RNA-protein or DNA-protein complexes in which the RNA or DNA molecule is non-covalently or covalently bound to the complex; (c) separating the complexes into compartments wherein most or all of the compartments contain no more than one complex; (d) subjecting the complexes to reaction conditions which allow target protein activity; and (e) selecting nucleic acid encoding the target protein on the basis of the activity associated therewith,
wherein step b) is performed in the absence of separate compartments for each complex.
Covalent linkages between DNA or RNA and the target protein can be generated by any technique known in the art, for example, mRNA display, phage display, bacterial display or yeast display. In particular, a covalent RNA-protein linkage can be generated using the technique of mRNA display, while a covalent DNA-protein linkage can be generated using the technique of covalent antibody display (CAD) (Reiersen et al., 2005), performing translation in compartments by covalent DNA display (Bertschinger and Neri, 2004), or using similar covalent display techniques such as those described by Stein et al., (2005).
Non-covalent linkages between DNA or RNA and the target protein can also be generated by any technique known in the art, for example, ribosome display, CIS display, or plasmid display. In particular, a non-covalent DNA-protein linkage can be generated in the absence of a compartment using CIS display (Odergrip et al., 2004), while a non-covalent RNA-protein linkage can be generated using the technique of ribosome display.
As indicated above, when the complex is a DNA-protein complex in which the DNA is non-covalently bound, step (b) of the process of the invention is performed in the absence of separate compartments for each complex. In other words, step (b) is un-compartmentalised. Specifically, when the complex generated is a DNA-protein complex in which the DNA is non-covalently bound, the generation step is performed without separating each member of the array from one another. In particular, the generation step is performed without separating each member of the array by in vitro compartmentalization (IVC). In a particularly preferred embodiment the generation step is performed without separating each member of the array in a water-in-oil emulsion.
Compartmentalisation can also be performed by any method known in the art which enables the complexes to be generated or separated such that all or substantially all of the compartments contain no more than one complex. In particular, it is preferred. that at least 70%, at least 80% or at least 90% of the compartments contain no more than one complex. For example, compartmentalization can be performed by separating members of the array or each complex into different wells on a microtitre or nanotitre plate, or by in vitro compartmentalization (IVC). In particularly, separation by IVC can involve separation into aqueous droplets in a water-in-oil emulsion or a water-in-oil-in-water emulsion.
The method of the present invention combines at least two different types of genotype-phenotype linkage selected from the list covalent linkage, non-covalent linkage and compartmentalization. In a preferred aspect of the invention the method utilized no more than two of these linkages. Thus in a particularly preferred embodiment the method utilizes the covalent or non-covalent linkage as the only genotype-phenotype linkage in step b). In other words, in this embodiment there is no compartmentalization in step b).
Covalent/non-covalent linkages between DNA or RNA and the protein in the absence of a compartment can be established in many different ways, for example, by ribosome display, mRNA display (Roberts and Szostak, 1997), CIS display (Odergrip et al., 2004) or covalent antibody display (CAD) (Reiersen et al., 2005). Specifically, covalent DNA-protein linkage can be realized in the absence of compartments by using CAD technique, while covalent RNA-protein linkage and non-covalent RNA-protein linkage can be established by mRNA display and ribosome display, respectively.
The present invention can be realized through a combination of many different linkages. For example, the present invention can be realized through a combination of ribosome display and in vitro compartmentalization, or through a combination of mRNA display, CIS display, or CAD display and IVC.
In a preferred aspect the process for the production of nucleic acid encoding a target protein is realized through a combination of ribosome display and in vitro compartmentalization. In particular such an process comprises:
(a) providing an array of mRNAs including one or more encoding the target protein; (b) incubating the array of mRNAs under conditions for ribosome translation to generate an array of ternary complexes each comprising an mRNA, a ribosome and protein translated from the mRNA; (c) incorporating the array of ternary complexes into aqueous phase droplets of a water-in-oil or a water-in-oil-in-water emulsion, wherein most or all of the aqueous phase droplets contain no more than one ternary complex; (d) subjecting the aqueous phase droplets to reaction conditions which allow protein activity; and (e) selecting nucleic acid encoding the target protein on the basis of the enzyme activity associated therewith.
Such a process according to the present invention may be termed “compartmentalized ribosome display” (CRD). CRD is applicable to a wide range of target proteins, including enzymes. CRD has the advantage that the linkage between the enzyme and the mRNA is non-covalent. Thus if the reaction conditions used in step (d) involve a raised temperature the ternary complexes generated in step (b) will fall apart and the enzyme will be released. This avoids the problems associated with enzyme mobility described above for prior art methods in which the enzyme is immobilized on a bead.
Emulsion droplets with ribosome display complexes inside can be sorted or selected in step (e) in many ways. Preferably they are sorted by fluorescence activated cell sorting (FACS) or using microfluidic techniques. Both techniques mainly exploit fluorescence based droplet sorting. However, droplets can also be separated by size, light diffraction or light absorption, depending on the reaction conditions used in step (d) and the protein activity that is being selected for.
Fluorescent based sorting methods are preferably used when the target protein is an enzyme. In this embodiment the reaction conditions employed in step (d) include a non-fluorescent substrate capable of being converted to a fluorescent product. Activity by the enzyme generates the fluorescent product, allowing FACs to be used to distinguish between fluorescent droplets containing an active enzyme and non- or less fluorescent droplets which contain no active enzyme or a less active enzyme.
In particular, CRD is applicable to nucleic acid processing enzymes such as reverse transcriptases, and allows for fast and efficient in vitro evolution.
In a further aspect the present invention provides a process for the production of nucleic acid encoding a target protein, which comprises:
(a) providing an array of mRNAs including one or more encoding the target protein, wherein the mRNAs comprise a substrate for an enzyme comprising the target protein or a co-enzyme thereof; (b) incubating the array of mRNAs under conditions for ribosome translation to generate an array of ternary complexes each comprising an mRNA, a ribosome and protein translated from the mRNA; (c) incorporating the array of ternary complexes, and optionally the co-enzyme, into aqueous phase droplets of a water-in-oil or a water-in-oil-in-water emulsion, wherein most or all of the aqueous phase droplets contain no more than one ternary complex; (d) subjecting the aqueous phase droplets to reaction conditions which allow enzyme activity; and (e) selecting nucleic acid encoding the target protein on the basis of the enzyme activity associated therewith.
In one embodiment of this aspect of the invention, where the nucleic acid processing enzyme is a DNA dependent DNA polymerase, the mRNA of step (a) can be ligated to a double stranded DNA adaptor molecule to provide the substrate.
CRD diversity is ˜10 9 -10 10 variants and is limited by IVC step. The new method is much more efficient, less time consuming and cheaper compared to high throughput screening (HTS), which can be used to screen ˜10 5 -10 6 mutant variants of reverse transcriptase. CRD diversity is about four orders of magnitude higher compared to HTS; thus many more beneficial mutants missed by HTS can be easily fished-out by compartmentalized ribosome display selection.
According to step (a), an array of mRNAs which are typically synthesized mRNAs is provided which includes one or more members of the array encoding the target protein. Where the target protein is reverse transcriptase the mRNAs comprise a substrate for an enzyme comprising the target protein or a co-enzyme thereof. In the subsequent selection step (e), the nucleic acid encoding the target protein is selected on the basis of the enzyme activity associated therewith. In this way, two embodiments of the invention are contemplated: one in which the enzyme activity is provided by the target protein and one in which the enzyme activity is provided by a co-enzyme of the target protein in the presence of the target protein. In the embodiment requiring the co-enzyme, this is incorporated into aqueous phase droplets of the water-in-oil emulsion of step (c), as is the array of ternary complexes. Where the enzyme comprises the target protein, no additional co-enzyme need to be incorporated into the aqueous phase droplets.
In step (b) of the process, the array of mRNAs is treated with ribosomes to generate an array of ternary complexes, each comprising an mRNA, a ribosome and protein translated from the mRNA. This step may be performed under any conditions suitable for typical in vitro translation of mRNA, as used for example in the technique of ribosome display. At this point, the ternary complexes may be purified, although this is not essential. The ternary complexes may be supplemented at this point with any co-substrates necessary for the subsequent enzyme activity whereupon the reaction mixture is typically emulsified to give approximately 10 10 water-in-oil compartments each typically having a mean diameter of approximately 2 to 3 μm. Even a small volume (25 μl) of in vitro translation reaction generates approximately 10 11 to 10 12 molecules of stored ribosomal complexes. A typical ribosome display method uses mRNAs lacking STOP codons, although STOP codon may be present (Matsuura et al., 2007). In order to achieve aqueous phase droplets in which most or all contain no more than one ternary complex the concentration of ternary complexes would have to be reduced by about two orders of magnitude as compared with corresponding concentration used in a typical ribosome display technique. Only a very small concentration of ternary complexes is used in this step of the process.
The enzyme may comprise a nucleic acid processing enzyme, which may be an RNA processing enzyme. The nucleic acid processing enzyme may comprise the target protein and may be selected from a nucleic acid polymerase, a nucleic acid ligase and a terminal deoxynucleotidyl transferase. As described in further detail herein, the nucleic acid polymerase may comprise a reverse transcriptase. In this embodiment, the mRNA encoding the reverse transcriptase is itself the substrate for the reverse transcriptase. Step (e) of selecting nucleic acid encoding the target protein, comprises selecting cDNA produced by the action of the reverse transcriptase, which cDNA encodes reverse transcriptase.
Where the target protein is a nucleic acid ligase, selection for RNA (DNA) ligases able to ligate RNA to RNA or DNA to RNA can be performed. Preferably, the reaction conditions which allow enzyme activity include a co-substrate comprising a nucleic acid linker or adaptor, which co-substrate further comprises an affinity ligand for attachment to a ligand binding partner or sequence tag for specific amplification of processed mRNA in RT-PCR. In the first case, the mRNA encoding the target protein is ligated to the co-substrate in those aqueous phase droplets which incorporate mRNA encoding a nucleic acid ligase. Preferably, the affinity ligand comprises biotin and the ligand binding partner comprises streptavidin. The step of selecting nucleic acid encoding the target protein comprises selecting mRNA incorporating the co-substrate by attachment to a solid phase comprising the ligand binding partner. In a typical process, a mutant library of ligase is translated in vitro and purified ternary complexes are diluted and emulsified in reaction buffer with biotin labeled DNA/RNA linker and/or adaptor. After bringing the emulsion to a temperature of 37° C. ribosome ternary complexes disassemble. Ligase will be released and the 3′ end of the mRNA will become accessible for the biotin labeled adaptor and subsequent ligation reaction. Biotin labeled mRNA encoding only active (or more active) variants of ligase will be purified on the streptavidin beads and may be amplified by RT-PCR.
In the second case the step of selecting nucleic acid encoding the target protein comprises selecting mRNA with attached sequence specific tag, which can be used for selective annealing site of primer for reverse transcription and subsequent PCR.
In a typical process, a mutant library of ligase is. translated in vitro and purified ternary complexes are diluted and emulsified in reaction buffer with DNA/RNA linker and/or adaptor. After bringing the emulsion to a temperature of 37° C. ribosome ternary complexes disassemble. Ligase will be released and the 3′ end of the mRNA will become accessible for the adaptor and subsequent ligation reaction. RNA encoding only active (or more active) variants of ligase will have specific linker sequence required for specific annealing of primer used in reverse transcription and may be efficiently amplified by RT-PCR.
It is also possible to select for terminal deoxynucleotidyl transferase (TdT). This enzyme works on RNA and incorporates deoxyribonucleotides, ribonucleotides, nucleotide analogues and similar. In this embodiment, the reaction conditions which allow enzyme activity include a co-substrate comprising dNTP which further comprises an affinity ligand for attachment to a ligand binding partner. As with the nucleic acid ligase, the affinity ligand may be biotin and the ligand binding partner streptavidin. Selecting nucleic acid encoding the target protein may comprise selecting mRNA incorporating the co-substrate by attachment to a solid phase comprising the ligand binding partner. A mutant library of TdTs may be translated in vitro and purified ribosome ternary complexes may have to be diluted and emulsified in reaction buffer with biotin labeled nucleotides, such as biotin-dUTP. The optimal working temperature for wild type enzyme is 37° C. At this temperature the ribosome ternary complexes will disassemble and the 3′ end of mRNA will become accessible for template independent polymerization reaction. TdT-encoding mRNA incorporating biotin labeled nucleotide is selected on the streptavidin beads and may subsequently be reversed transcribed and amplified by RT-PCR.
In a further embodiment, the target protein comprises a reverse transcriptase helper enzyme such as a helicase, pyrophosphatase, processivity factor, RNA binding protein or other protein able to improve a reverse transcription reaction in the presence of reverse transcriptase. In this embodiment, the nucleic acid processing enzyme comprises a reverse transcriptase, which is the co-enzyme incorporated into the aqueous phase droplets of the water-in-oil emulsion. In step (e) of selecting nucleic acid target protein; cDNA is selected, which cDNA is produced by the action of the reverse transcriptase and which encodes the reverse transcriptase helper enzyme. The presence of the reverse transcriptase helper enzyme in the aqueous phase facilitates reverse transcription of the mRNA which encodes the helper. Thus, mRNA which is reverse transcribed forms cDNA which encodes the helper and this may be PCR amplified.
In a further embodiment, the target protein comprises an RNase inhibitor. In this embodiment, the nucleic acid processing enzyme comprises an RNase. The step (e) of selecting nucleic acid encoding the target protein comprises selecting mRNA undegraded by RNase. In this embodiment, the RNase is incorporated as the co-enzyme into the aqueous phase droplets of the water-in-oil emulsion. Once reaction conditions allow enzyme activity, any droplets not containing effective RNase inhibitor would exhibit RNase activity whereby the mRNA would be degraded. Thus, mRNA encoding RNase inhibitor effective at the reaction conditions used would survive. Typically, a mutant library of RNase inhibitors is translated in vitro and purified ribosome ternary complexes are diluted and emulsified in reaction buffer with appropriate RNase. In an alternative arrangement RNase can be delivered later by emulsion micro droplets. mRNA encoding only active (or more stable) RNase inhibitor will be purified and amplified by RT-PCR.
Compartmentalized ribosome display can also be used for reaction buffer exchange in in vitro compartmentalization where selection buffer is incompatible with in vitro translation mixture and substrate conversion to product has to be performed under strictly controlled reaction conditions.
The nucleic acid encoding the target protein which has been selected on the basis of the enzyme activity associated therewith may be DNA or RNA, as discussed herein. The array may be converted or amplified to form DNA or RNA. In a preferred arrangement, the array is converted or amplified to form the array of mRNAs of step (a) of the process and is subject to one or more further cycles of steps (b) to (e) so as to enrich further the array with increasing amounts of mRNAs encoding the target protein.
The step (d) of subjecting the aqueous phase droplets to reaction conditions which allow enzyme activity provides the basis for selection step (e) where those nucleic acids encoding the target protein are selected. A wide range of reaction conditions may be used in step (d) to provide selection pressure. In one example, the reaction conditions include a temperature above the optimum temperature for a wild type enzyme. These reaction conditions may be used to select a mutant enzyme which is more thermostable than wild type enzyme or which has a greater reaction velocity at that temperature or an altered temperature-activity profile. Mutant enzymes may have to operate at higher sensitivities than wild type enzymes because concentrations of mRNA in the aqueous phase droplets are approximately 400 pM. Mutant enzymes may also have to perform more accurately. All of these selection pressures are particularly important in relation to reverse transcriptases. As well as physical conditions, the reaction conditions may include alterations in buffer, concentrations of other factors such as metal ions and pH.
Many more different selection pressures can be applied in CRD selecting for better reverse transcriptases: 1) selection for more soluble enzymes which are less prone to aggregation—ternary complexes (before emulsification) have to be preincubated with hydrophobic material in order to eliminate proteins with surface exposed hydrophobic residues; 2) selection for very fast enzymes—reverse transcription reaction times have to be gradually reduced during selection cycles; 3) selection for enzymes synthesizing long cDNA—gradual prolongation of mRNA library used in CRD and as a consequence synthesis of longer cDNA; 4) selection for enzymes able to transcribe through secondary structures—secondary structure forming sequences have to be introduced into mRNA library used in CRD; 5) selection for enzymes working in buffers which are different from RT buffer (for example in PCR, one step RT-PCR buffer or with denaturing agents)—CRD selection has to be performed in buffer of our choice; 6) selection for enzymes able to incorporate nucleotide analogues—selection has to be performed in RT buffer with biotin labeled nucleotide analogues with subsequent cDNA purification on streptavidin beads.
Compartmentalized ribosome display (CRD) is also suitable for many fluorescence activated cell sorting (FACS) applications. Protein of interest has to be displayed in ribosome display format. Optionally purified (or just diluted many times) ternary complex comprising mRNA-ribosome-protein (tRNA) mixed with non fluorescent substrate (S) in reaction buffer should be emulsified producing double water-in-oil-in-water emulsions (Bernath et al., 2004; Mastrobattista et al., 2005). Active variants of compartmentalized enzymes will convert substrate (S) to fluorescent product (P) allowing FACS to distinguish between fluorescent (active enzyme inside) and “dark” (inactive enzyme inside) droplets. Contrary to previously published examples, where enzymatic reaction has to be performed in transcription/translation mixture, CRD allows for complete buffer exchange and selection for active enzymes in more native (required) conditions ( FIG. 10 .)
Selection and evolution of thermostable DNA polymerases using CRD is also possible ( FIG. 11 .). Polymerase of interest has to be displayed in ribosome display format. Optionally purified (or just diluted many times) ternary complex comprising mRNA-ribosome-polymerase can be used to prepare reaction mixture with reverse transcriptase (helper enzyme), dNTP's and primer set in PCR buffer. Reaction solution should be emulsified producing water-in-oil emulsion. In first RT step—reverse transcriptase has to synthesize cDNA, which subsequently will serve as a target for second PCR step—cDNA amplification by ribosome displayed DNA polymerase. One of the primers used in PCR can have biotin for optional subsequent purification with streptavidin beads and non-complementary 5′ end. After RT-PCR emulsions should be broken, newly synthesized DNA fragment can be purified via biotin and reamplified using new primer set, which will contain one primer with sequence non-complementary to cDNA, but identical to 5′ part of primer used in first amplification reaction (selective amplification of DNA over cDNA background). More active variants of DNA polymerase will be enriched over less active variants and can be used for further analysis or next selection-round ( FIG. 11 .).
Important features of the compartmentalized ribosome display technology are:
1) the genotype is maintained by an mRNA library, which is especially useful in selecting RNA processing enzymes;
2) the selection unit is a ternary complex of mRNA-ribosome-protein (tRNA) and this can readily purified by ultracentrifugation, gel-filtration, affinity tag purification and other simple means;
3) the reaction buffer can be exchanged thereby enabling the selection unit to be transferred (with or without purification) to a new reaction mixture and at the same time be diluted by a factor of 100 to 200 (in order to adjust the number of ribosome complexes after emulsification to less than one molecule per reaction compartment);
4) the mRNA library diversity of CRD is limited only by the diversity of the in vitro compartmentalization and is less than 10 10 different variants;
5) once emulsified, the selection reaction can be performed at a broad range of temperatures from 4° to 94° C. because emulsions are stable over these temperatures;
6) if selections performed at elevated temperatures (30° C. and above), the ternary complexes will dissociate but remain compartmentalized so as not to lose the genotype-phenotype link, releasing mRNA and in vitro translated protein.
The compartmentalized ribosome display process of the present invention has been found to work particularly well in promoting evolution of new reverse transcriptase enzymes. As an example, M-MuLV reverse transcriptase (Gerard et al., 1986, pRT601) may be used for selection (the enzyme including a N terminal His tag for purification). This reverse transcriptase has a temperature optimum for activity at 42° C. and is active at temperatures up to 50° C. An array of mRNAs encoding the M-MuLV reverse transcriptase may be subjected in step (d) of the process of the present invention to reaction conditions which include primer and dNTPs required for cDNA synthesis at an incubation temperature in the range of from 50° C. to 60° C. At these elevated temperatures stored ribosomal complexes stable at 4° C. quickly dissociate releasing into solution a reverse transcriptase substrate (mRNA) and enzyme.
In one embodiment, in vitro translated reverse transcriptase M-MuLV released from ribosomal complex has C terminal fusion with phage lambda outer surface protein D used in ribosome display construct as a spacer to remain in ribosomal tunnel (Matsuura and Pluckthun, 2003) and covalently bound tRNA, because translation was not terminated properly. Protein D is very well expressed, soluble, stable protein with unfolding transition temperature ˜57° C. (Forrer and Jaussi, 1998) and therefore is good fusion partner for selection of thermostable reverse transcriptase.
In compartmentalized ribosome display selection method only fully active variants of reverse transcriptase can perform synthesis of cDNA, which encodes the same active enzyme. In 1 hr, after the reverse transcription reaction is completed, emulsion is broken, cDNA is purified and amplified by nested PCR. Because of the selection nature of CRD only cDNA, which encodes active variants of reverse transcriptase, able to perform full length cDNA synthesis, will be amplified and if necessary transferred to the next selection round. In order to eliminate undesirable mutations in T7 polymerase promoter region, ribosome binding site (RBS) and protein D sequence, amplified DNA, encoding only M-MuLV sequence, may be ligated to native 5′ and 3′ terminal fragments in such way that original ribosome display construct is restored and next selection round can be performed.
In five selection rounds enzyme variants with specific activities at 50° have been identified, which are 2-4 times better as compared to the activity of the primary enzyme used for library preparation. Some of proteins are faster, some—more thermostable. Many selected M-MuLV variants have mutations D524G or D583N, which turn off RNase H activity of reverse transcriptase and improve cDNA synthesis as well as thermostability (Gerard et al., 2002). Many more variants of selected M-MuLV reverse transcriptases have other different beneficial mutations (H204R; H638R; T197A; M289V; E302K; T306A; N454K; Y64C; E69G; Q190R; V223M; F309S; L435P; E562K) mentioned and described before (U.S. Pat. No. 7,056,716; US20060094050A1; U.S. Pat. No. 7,078,208; US20050232934A1; WO07022045A2). In addition to that we have found many new hot spots in reverse transcriptase amino acids sequence. Some mutations repeat very frequently and are of very high importance, what was shown analyzing purified mutants (Example 2). Thus we can state, that our CRD technology is very fast and robust selection method, efficiency of which was confirmed by direct evolution and improvement of M-MuLV reverse transcriptase. As proof of principle we have selected variants of M-MuLV reverse transcriptase working better at higher temperatures.
In a further aspect, the present invention provides a reverse transcriptase enzyme obtainable by the process as described herein.
In a further aspect, the present invention provides a reverse transcriptase enzyme having an optimum activity at a temperature above 42° C., preferably at least 50° C. and more preferably in the range of from 50° C. to 60° C. Reverse transcriptase enzymes may be selected according to the process described herein by applying reaction conditions having an elevated temperature, preferably of at least 50° C. In this aspect of the invention, a reverse transcriptase enzyme may be selected which has an activity-temperature profile which is shifted in comparison with wild type enzyme to increase the temperature at which optimum activity is observed.
In a further aspect, the invention provides a reverse transcriptase enzyme which comprises a MMLV reverse transcriptase amino acid sequence with a mutation at one or more of the following amino acid positions:
D200,
D653,
L603,
T330,
L139,
Q221,
T287,
I49,
N479,
H594,
F625,
H126,
A502,
E607,
K658,
P130,
Q237,
N249,
A307,
Y344,
Q430,
D449,
A644,
N649,
L671,
E673,
M39,
Q91,
M66,
W388,
I179
E302
L333
R390
Q374 and
E5
Where the mutation is at D653 it is preferred that the mutation is not D653N. Where the mutation is at L603 it is preferred that the mutation is not L603A. Further, where the mutation is at H594 it is preferred that the mutation is not H594A.
It is preferred that the mutations at the above positions are point mutations.
Preferably, the reverse transcriptase has one or more of the following mutations:
D200N, A or, G, D653N, G, A, H or, V,
L603W or M, T330P,
L139P, Q221R,
T287A,
I49V or T,
N479D,
H594R
F625S
H126S
or Q,
or L,
or R,
A502V,
E607K, G or A,
K658R or Q
P130S,
Q237R,
N249D,
A307V,
Y344H,
Q430R,
D449G
A644V
N649S,
or A,
or T,
L671P,
E673G or K,
M39V or L,
Q91R
M66L,
W388R,
or L,
I179T
E302K
L333Q
R390W
Q374R and E5K
or V
Each of these mutations is found, for example, in mutant enzymes having a higher activity at 50° C. as compared with the corresponding wild type enzyme. Further details of these mutations are described in the specific examples.
In particularly preferred aspect of the invention the mutant enzyme has at least two mutations. In one embodiment the two mutations are at D200 and at L603. For example the mutations are D200N and L603W. In an alternative embodiment the mutations are at N479 and H 594. For example the mutations are N479D and H594R.
In a further aspect, the invention provides a reverse transcriptase enzyme having an optimum activity at a temperature above 37° C., wherein the activity at 50° C. is at least 120% of the activity at 37° C. Preferably, the activity at 50° C. is at least 130%, more preferably at least 160% of the activity at 37° C.
In a further aspect, the present invention provides a mutant reverse transcriptase enzyme having an activity at 50° C. which is at least twice that of the corresponding wild type enzyme.
In a further aspect, the present invention provides a mutant reverse transcriptase enzyme having a specific activity at 37° C. which is at least 130% of the corresponding wild type enzyme. Preferably, the specific activity of the mutant reverse transcriptase enzyme is at least 140%, more preferably at least 150% and particularly preferably at least 160% of the specific activity of the corresponding wild type enzyme. It has been found as described herein that partially purified wild type enzyme specific activity at 37° C. is approximately 200000 U/mg. Specific mutant reverse transcriptase enzymes obtainable in accordance with the present invention are discussed in further detail in the specific examples.
In a further aspect, the present invention provides a mutant reverse transcriptase enzyme having a thermostability of at least 1.5 times that of the corresponding wild type enzyme. Thermostability is measured in the present application as residual activity at 37° C. following treatment at 50° C. for 5 minutes. Preferably, the thermostability of the mutant reverse transcriptase enzyme is at least 1.5 times, more preferably at least 2 times, still more preferably at least 2.5 times that of the corresponding wild type enzyme. Typically, residual activity at 37° C. of the wild type reverse transcriptase enzyme is approximately 11% as compared with untreated enzyme.
It is preferred that the reverse transcriptase enzyme according to the invention comprises an MMLV reverse transcriptase.
In a further aspect, the present invention provides a polynucleotide, such as an mRNA or DNA, encoding a reverse transcriptase as described herein.
The reverse transcriptases according to the present invention may be used in a variety of molecular biology techniques such as RT-PCR (qRT-PCR, etc). A kit for RT-PCR may be provided in which the reverse transcriptase of the kit is a reverse transcriptase according to the present invention.
DETAILED DESCRIPTION OF INVENTION
The invention will now be described in further detail, by way of example only, with reference to the accompanying figures and appendices:
FIG. 1 . The experimental scheme of Example 1. Two plasmids pET_his_MLV_pD (encoding Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase fused to protein D spacer) and pET_his_del_pD (encoding inactivated (57 amino acids deletion in pol domain) Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase fused to protein D spacer) were used to synthesize PCR fragments. PCR fragments furtheron are used in transcription reaction and synthesis of mRNA lacking STOP codon at the 3′ end. Purified mRNA is mixed with ratio 1:50=MLV (active RT):del (inactive RT) and used for in vitro translation reaction. During translation reaction ribosomal complex synthesizes protein and stops at the end of mRNA lacking STOP codon. Mixture of ternary complexes (TC) is purified by ultracentrifugation on sucrose cushions. Purified ternary complexes (<3*10 9 molecules taken) already containing mRNA linked to in vitro translated MLV reverse transcriptase are used to prepare reverse transcription reaction mix supplemented with external dNTP set and primer for RT reaction. Ice-cold RT reaction mixture is emulsified giving ˜1*10 10 water in oil compartments ˜2 μm in size. Emulsified RT reaction mixture (less than one TC (mRNA+MLV RT) per compartment is incubated for 1 hr at 42° C. in order to perform RT reaction. After the temperature of compartmentalized RT reaction mixture is raised most of TC dissociate releasing mRNA and reverse transcriptase. Successful RT reaction is performed only in compartments containing active MLV reverse transcriptase (MLV_pD) and no cDNA is synthesized in compartments with inactive reverse transcriptase (del_pD). Subsequent PCR amplifies cDNA and enrichment of active reverse transcriptase (MLV_pD) genes over inactive reverse transcriptase (del_pD) is observed.
FIG. 2 . The structural scheme of pET_his_MLV_pD plasmid.
FIG. 3 . Example 1—the agarose gel electrophoresis of first PCR performed on cDNA synthesized during CRD selection. Primers used: RD_Nde (SEQ ID No: 9) and pD — 55 (SEQ ID No: 10). Expected length of PCR fragments was 2185 bp for MLV_pD and 2014 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well.
FIG. 4 . Example 1—the agarose gel electrophoresis of nested PCR for partial gene amplification performed on first PCR product. Primers used: M_F (SEQ ID No: 11) and M — 2R (SEQ ID No: 12). Expected length of PCR fragments was 907 bp for MLV_pDa and 736 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well.
FIG. 5 . Example 1—the agarose gel electrophoresis of nested PCR for full gene amplification performed on first PCR product. Primers used: M_Esp (SEQ ID No: 13) and M_Eri (SEQ ID No: 14). Expected length of PCR fragments was 2077 bp for MLV_pDa and 1906 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well.
FIG. 6 . The experimental scheme of CRD selection in Example 2. PCR fragments encoding mutants library of reverse transcriptase (in fusion with protein D) MLV_pD was used to synthesize mRNA. Purified mRNA was used for in vitro translation reaction. Ternary complexes (TC) of mRNA-ribosome-MLV_pD (tRNA) were formed in translation mixture and stabilized by low temperature and high concentration of Mg 2+ ions. Mixture of TC was purified by ultracentrifugation on sucrose cushions. Precipitated TC was dissolved in ice-cold buffer (50 mM Mg 2+ ) and used to prepare reverse transcription reaction mix supplemented with external dNTP set and primer for RT reaction. Ice-cold RT reaction mixture was emulsified giving ˜1*10 10 water in oil compartments ˜2 μm in size. Optimal reaction temperature of MLV RT is ˜42° C. In order to select for reverse transcriptase variants, which are working better at higher temperatures emulsified RT reaction mixture (less than one TC (mRNA+MLV RT) per compartment) was incubated for 1 hr at 50° C. At this temperature successful synthesis of full length cDNA was performed better in compartments containing more active or thermostable MLV reverse transcriptase variants. Subsequent PCR was used to amplify full length cDNA and enrichment of more active and thermostable reverse transcriptase genes was performed. By PCR amplified genes were moved back to CRD format restoring intact 5′ (START fragment—T7 polymerase promoter, SD and his-tag coding sequences) and 3′ (END fragment—gs linker, protein D and second gs linker) sequences by ligation PCR. Reconstructed PCR fragment, containing enriched library of reverse transcriptase genes, was used for subsequent mRNA transcription and next CRD selection round. Each selection round was performed at higher and higher temperatures of RT reaction: 50° C. (1 st round); 52.5° C. (2 nd round); 55° C. (3 rd round); 57.5° C. (4 th round) and 60° C. (5 th round).
FIG. 7 . The scheme of PCR fragment reconstruction before new round of CRD selection. Mutated MLV RT library was digested with Esp3I (NcoI compatible end) and EcoRI and ligated with START (244 bp) and END (398 bp) fragments in order to get PCR fragment suitable for CRD selection. START fragment (containing T7 polymerase promoter, SD and his-tag coding sequences) was constructed by PCR amplification of initial 983 bp START fragment (target—plasmid pET_his_del_pD (SEQ ID No: 2), primers—pro-pIVEX (SR) ID No: 3) and M — 1R (SEQ ID No: 15)) and subsequent digestion with NcoI (recognition sequence C↓CATGG) giving 244 bp DNA fragment. END fragment (containing gs linker, protein D and second gs linker sequences) was constructed by PCR amplification of initial 1039 bp END fragment (target—plasmid pET_his_del_pD (SEQ ID No: 2), primers—M — 3F (SEQ ID No: 16) and pD-ter (SEQ ID No: 4)) and subsequent digestion with EcoRI (recognition sequence G↓AATTC) giving 398 bp DNA fragment.
FIG. 8 . Reverse transcriptase activities of mutant RT variants measured at 37° C., 50° C. and residual activity at 37° C. after 5 min incubation at 50° C. Reverse transcriptase activity at 37° C. is normalized to be always 100% and is omitted. Thus only two types of columns (percents of RT activity at 50° C. and residual RT activity at 37° C. after 5 min incubation at 50° C.) are shown. As a control is given wt M-MuLV reverse transcriptase used for mutants library construction. This primary enzyme is expressed in the same vector and purified in the same way as mutant variants of RT. An average value of mutant RT activity at 50° C. for all tested mutants is about ˜92% and is more than 2 times higher comparing to wt enzyme (45%). An average residual activity of mutant RT variants at 37° C. − after 5 min preincubation at 50° C. is 12% (wt enzyme—11%).
FIG. 9 . Specific activity (u/mg of protein) of partially purified wt and mutant RT variants measured 10 min at 37° C.
FIG. 10 . The proposed experimental scheme of CRD selection using FACS. Protein of interest is displayed in ribosome display format. Purified (or just diluted many times) ternary complex comprising mRNA-ribosome-protein (tRNA) is mixed with non fluorescent substrate (S) in reaction buffer and subsequently emulsified producing double water-in-oil-in-water emulsions. Active variants of compartmentalized enzymes will convert substrate (S) to fluorescent product (P) allowing FACS to distinguish between fluorescent (active enzyme inside) and “dark” (inactive enzyme inside) droplets.
FIG. 11 . The proposed experimental scheme for selection and evolution of thermostable DNA polymerases using CRD. Polymerase of interest has to be displayed in ribosome display format. Optionally purified (or just diluted many times) ternary complex comprising mRNA-ribosome-polymerase can be used to prepare reaction mixture with reverse transcriptase (helper enzyme), dNTP's and primer set in PCR buffer. Reaction solution should be emulsified producing water-in-oil emulsion. In first RT step—reverse transcriptase has to synthesize cDNA, which subsequently will serve as a target for second PCR step—cDNA amplification by ribosome displayed DNA polymerase. One of the primers used in PCR can have biotin for optional subsequent purification with streptavidin beads and non-complementary 5′ end. After RT-PCR emulsions should be broken, newly synthesized DNA fragment can be purified via biotin and reamplified using new primer set, which will contain one primer with sequence non-complementary to cDNA, but identical to 5′ part of primer used in first amplification reaction (selective amplification of DNA over cDNA background). More active variants of DNA polymerase will be enriched over less active variants and can be used for further analysis or next selection round.
FIG. 12 . The experimental scheme of Example 4. In this experimental setup M-MuLV reverse transcriptase is used as DNA dependent DNA polymerase. Two plasmids pET_his_MLV_D583N_pD (encoding RNase H minus Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase fused to protein D spacer) and pET_his_del_pD (encoding inactivated reverse transcriptase fused to protein D spacer—57 amino acids deletion in pol domain and point mutation D583N in RNase H domain) were used to synthesize PCR fragments. PCR fragments furtheron are used in transcription reaction. Purified mRNA is mixed with ratio 1:20=MLV_D583N_pD (active RT):del_pD (inactive RT) and used to prepare mRNA/dsDNA complex by dsDNA ligation to mRNA mix using T4 DNA ligase. mRNA/dsDNA complex was used for in vitro translation reaction. During translation reaction ribosomal complex synthesizes protein and stops at the end of mRNA (at the beginning of mRNA/DNA hybrid). Mixture of ternary complexes (TC) is purified by ultracentrifugation on sucrose cushions. Purified ternary complexes (<3*10 9 molecules taken) already containing mRNA/dsDNA linked to in vitro translated polymerase (M-MuLV reverse transcriptase) are used to prepare elongation reaction mix supplemented with external biotin-dUTP. Ice-cold reaction mixture is emulsified giving ˜1*10 10 water in oil compartments ˜2 μm in size. Emulsified elongation reaction mixture (less than one TC (mRNA/dsDNA+polymerase) per compartment is incubated for 30 min at 37° C. in order to incorporate biotinylated nucleotide. After the temperature of compartmentalized reaction mixture is raised most of TC dissociate releasing mRNA/dsDNA complex and polymerase. Successful incorporation reaction in to dsDNA substrate is performed only in compartments containing active polymerase (reverse transcriptase MLV_D583N_pD) and no cDNA is synthesized in compartments with inactive polymerase (del_pD). After the emulsions are broken excess of biotin-dUTP is removed using gel-filtration mini-column. Biotinylated mRNA/dsDNA complex is purified on streptavidin beads and used to synthesize cDNA. Subsequent PCR amplifies cDNA and enrichment of active polymerse (reverse transcriptase—MLV_D583N_pD) genes over inactive polymerase (del_pD) is observed.
FIG. 13 . Determination of biotin-dUTP incorporation efficiencies into mRNA/dsDNA complex and into self primed mRNA. Picture of RT-PCR performed on samples of mRNA/dsDNA (MLV_D583N_pD) and mRNA (del_pD) after the incorporation of dTTP or biotin-dUTP. Predicted amplicons size are 907 bp for MLV_D583N_pD and 736 bp for del_pD cDNA. PCR products were analyzed on 1% agarose gel loading 10 μl of PCR mix per well.
FIG. 14 . General control of mRNA/dsDNA complex existence by incorporation of dTTP (biotin-dUTP) and [α-P 33 ]dATP. Radioactive dATP should be introduced into dsDNA substrate subsequentially after the incorporation of initial dTTP or biotin-dUTP. A ethidium bromide visualized agarose gel (mRNA or mRNA/dsDNA bands ˜2.5 kb). B—the same gel as in A dried on filter paper and visualized using Cyclone Phosphor Imager (Perkin-Elmer, Wellesley, Mass.). Labelled mRNA/dsDNA complex and/or only dsDNA bands are observed. C—structure and sequence of dsDNA counterpart in mRNA/dsDNA complex SEQ ID NOs.: 21 and 22.
FIG. 15 . The resultant final RT-PCR fragments analysis of Example 4. Predicted amplicons size are 907 bp for MLV_D583N_pD and 736 bp for del_pD cDNA. PCR products were analyzed on 1% agarose gel loading 10 μl of PCR mix per well. RT-PCR samples before streptavidin beads corresponds to the ratio of active and inactive polymerase genes 1:20 (almost only delpD fragment ˜736 bp is visible). RT-PCR samples after the purification on streptavidin beads corresponds to the ratio of active and inactive polymerase genes after the single selection round ˜1:1. An enrichment factor of ˜20 is observed in this selection.
FIG. 16 . Some examples of alkaline agarose gels used to determine highest temperature of 1 kb and 4.5 kb cDNA synthesis reaction. PCR machine—Eppendor Mastercycle Gradient. A-D—1 kb cDNA synthesis (M-MuLV (wt), D200N, L603W and Q221R); temperature gradient 41.9° C., 43.6° C., 45.5° C., 47.8° C., 50.4° C., 53.1° C., 55.8° C., 58.1° C., 60.1° C., 62.1° C.; size standart—DNA Fast Ruler Middle Range (Fermentas). E-G—4.5 kb cDNA synthesis (M2, M3 and M4); temperature gradient 49.8° C., 51.5° C., 53.4° C., 55.7° C., 58.3° C., 61.0° C., 63.7° C., 66.1° C., 68.0° C., 70.0° C.; size standart—Zip Ruler Express DNA ladder 2 (Fermentas).
Appendix 1. The general scheme of mutations found in initial MLV RT library (sequence between NcoI and EcoRI restriction sites—SEQ ID No. 24). 23 nucleotide mutations were found among 10 sequenced genes (1 transversion, 20 transitions—mutated positions are underlined, mutations indicated above the sequence, 2 deletions—underlined and indicated as dashed line above the sequence) giving 15 amino acids exchanges, 6 silent mutations, 1 stop codon and 2 frame shifts of coding frame—on average 1-2 amino acids substitutions per gene.
Appendix 2. The CLUSTALW alignment of all 104 protein sequences without N terminal His tag in order to have the same numeration of amino acids as is usually used in literature. Wild type sequence denoted as MLV (SEQ ID No: 25) is always given as first sequence (mutated sequences represent SEQ ID Nos: 26 to 128 based on the order in which they are shown). Mutations are marked using white font color in black background. Amino acids positions, mutations of which somehow improve M-MuLV reverse transcriptase properties and are described in different patent applications are marked in the alignment as columns of amino acids (white font) highlighted in grey. Mutations originating from our selection and located in grey columns indicate that our selection procedure precisely targeted the beneficial hot spot or even exact amino acid mutations described elsewhere. Sequences of analyzed proteins, activity of which at 50° C. was substantially better as compared to the primary wt M-MuLV (70% and more as compared to 45% of wt activity) are highlighted in grey.
Appendix 3. List of mutations found in all selected RT variants. Proteins are sorted by decreasing number of mutations.
Appendix 4. Mutations frequency (in decreasing order) of selected RT variants. Names of analyzed proteins, which activity at 50° C. was substantially better as compared to primary wt M-MuLV (70% and more comparing to 45% of wt activity) are highlighted in grey.
Appendix 5. Summarized table of data on M-MuLV (wt) reverse transcriptase and single mutants, which contains: name of protein; selection frequency (number of sequenced mutants, which had exact mutation and the number in the parentheses indicates total number of particular amino acid mutations found in selection); protein concentration (mg/ml); reverse transcriptase specific activity at 37° C. (u/mg); relative activity at 50° C. (%); relative residual activity at 37° C. after 5 min enzyme incubation at 50° C. (%); specific RNase H activity of protein (u/mol); relative RNase H activity (%) and highest temperature of 1 kb cDNA synthesis reaction.
Appendix 6. Summarized table of data on M-MuLV (wt) reverse transcriptase and single mutants, which contains: name of protein; protein concentration (mg/ml); reverse transcriptase specific activity at 37° C. (u/mg); relative activity at 50° C. (%) and highest temperature of 1 kb and 4.5 kb cDNA synthesis reaction.
Appendix 7. Sequence and information relating to SEQ ID Nos: 1 to 23.
Example 1
CRD—Proof of Principle
To provide proof of principle for Compartmentalized Ribosome Display selection system test selection was performed. Typical proof of principle experiment should give positive signal for active enzyme (in our case RT-PCR fragment for original MLV reverse transcriptase) and no signal for inactive enzyme (no RT-PCR fragment for inactivated MLV reverse transcriptase). More sophisticated experiment is to use mixture of genes with defined ratio encoding active and inactive enzymes. As a result of successful experiment genes encoding active enzyme should be enriched over genes encoding inactive enzyme.
General scheme of experiment is shown in FIG. 1 . Two plasmids pET_his_MLV_pD (encoding Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase fused to protein D spacer) and pET_his_del_pD (encoding inactivated (57 amino acids deletion in pol domain) Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase fused to protein D spacer) were used to synthesize PCR fragments. Further PCR fragments were used in transcription reaction for synthesis of mRNA, which lacks STOP codon at the 3′ end. Purified mRNAs resulting from the two abovementioned PCR fragments were mixed with a ratio 1:50=MLV (active RT):del (inactive RT) and used for in vitro translation reaction. During translation reaction ribosomal complex synthesizes protein and stops at the end of mRNA lacking STOP codon. Translation reaction was stopped by dilution with ice-cold buffer containing 50 mM Mg 2+ . Low temperature, high concentration of Mg 2+ ions and absence of STOP codon at the end of mRNA stabilize ternary complexes (TC) of mRNA-ribosome-protein (tRNA). Mixture of ternary complexes (TC) was purified by ultracentrifugation on sucrose cushions. Ultracentrifugation was optimized in such a way that TC (˜3.5 MDa) were precipitated at the bottom of ultracentrifugation tube, meanwhile small molecular weight molecules, proteins and most of free mRNA (˜0.9 MDa) remained in the supernatant. Precipitated TCs were dissolved in the ice-cold buffer (50 mM Mg 2+ ). Purified ternary complexes (<3*10 9 molecules taken) already containing mRNA linked to in vitro translated MLV reverse transcriptase were used to prepare reverse transcription reaction mix supplemented with external dNTP set and primer for RT reaction. Ice-cold RT reaction mixture was emulsified yielding ˜1′10 10 water in oil compartments ˜2 μm in size. Emulsified RT reaction mixture (less than one TC (mRNA+MLV RT) per compartment was incubated for 1 hr at 42° C. in order to perform RT reaction. After the temperature of compartmentalized RT reaction mixture is raised most of TCs dissociate releasing mRNA and reverse transcriptase. Successful RT reaction is performed only in compartments containing active MLV reverse transcriptase (MLV_pD) and no cDNA is synthesized in compartments with inactive reverse transcriptase (del_pD). Subsequent PCR ensures the amplification of synthesized cDNA and enrichment of active reverse transcriptase (MLV_pD) genes over inactive reverse transcriptase (del_pD) is observed.
Methods and Materials
Initial plasmid pET_his_MLV_pD (SEQ ID No: 1 and FIG. 2 ) was constructed by modification of pET type plasmid in T7 polymerase promoter and Shine-Dalgarno sequences region and insertion of MLV H+ reverse transcriptase coding sequence (306-2363 on SEQ ID No: 1) with N-terminal His-tag (258-305 on SEQ ID No: 1) and C-terminal fusion with glycine-serine (gs) linker (2364-2393 on SEQ ID No: 1), part of protein D (pD) from phage lambda (2394-2669 on SEQ ID No: 1) and second glycine-serine (gs) linker (2670-2759 on SEQ ID No: 1). N-terminal His-tag is used for protein express purification. C-terminal fusion has to remain in ribosome tunnel during protein in vitro translation and formation of mRNA-ribosome-MLV (tRNA) ternary complex.
M-MuLV reverse transcriptase has two main enzymatic activities: RNA dependent DNA polymerase and RNase H. Reverse transcriptase RNase H activity was turned off introducing point mutation D583N (single nucleotide G to A exchange at position 2055 in plasmid pET_his_MLV_pD, SEQ ID No: 1). Aspartate 583 is located in RNase H active site, is involved in Mg ion binding and is crucial for RNase H activity. New plasmid is identified as pET_his_MLV_D583N_pD and was used for further construction of next plasmid pET_his_del_pD (SEQ ID No: 2), which encodes inactivated reverse transcriptase. Plasmid pET_his_MLV_D583N_pD was digested with restriction endonuclease XmaJI (recognition sequence C↓CTAGG—positions 1047 and 1218 on SEQ ID No: 1). Gene fragment 171 bp in length was removed and digested plasmid was self-ligated, yielding plasmid pET_his_del_pD (SEQ ID No: 2), which encodes reverse transcriptase gene shorter by 171 nucleotides or 57 amino acids, without shift in protein translation frame.
It was important to have the same reverse transcriptase gene: 1) shorter in length (for easy PCR detection); 2) inactive (it was confirmed experimentally that deletion of 57 amino acids in polymerase domain completely inactivated polymerase activity and mutation D583N inactivated RNase H activity); and 3) without frameshift (any frameshift will result in appearance of STOP codons, which are not compatible with ribosome display format).
Preparation of PCR fragments for in vitro transcription. PCR mixture was prepared on ice: 20 μl-10× Taq buffer with KCl (Fermentas); 20 μl-2 mM of each dNTP (Fermentas); 12 μl-25 mM MgCl 2 (Fermentas); 16 μl—DMSO (D8418—Sigma); 4 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1 μl—100 μM pro-pIVEX primer (SEQ ID No: 3); 1 μl-100 μM pD-ter primer (SEQ ID No: 4); 122 μl water-mixture divided into two tubes 2×98 μl. To 2×98 μl of PCR master mix were added either 2 μl of pET_his_MLV_pD (diluted to ˜1 ng/μl) or 2 μl of pET_his_del_pD (diluted to ˜1 ng/μl). The cycling protocol was: initial denaturation step 3 min at 94° C., 30 cycles (45 sec at 94° C., 45 sec at 53° C., and 2 min at 72° C.) and final elongation 5 min at 72° C. Amplification was ˜7000 fold from 2 ng of plasmid (7873 bp) target to −5 μg (50 ng/μl) of amplified product (2702 bp PCR fragment for pET_his_MLV_pD; 2531 bp-PCR fragment for pET_his_del_pD).
Transcription mixture was prepared: 40 □l-5×T7 transcription buffer (1 M HEPES-KOH pH 7.6; 150 mM Mg acetate; 10 mM spermidin; 0.2 M DTT); 56 □l-25 mM of each NTP (Fermentas); 8 □l-20 u/□l T7 RNA polymerase (Fermentas); 4 □l-40 u/□l RiboLock RNase inhibitor (Fermentas); 52 □l nuclease-free water-mixture divided into two tubes 2×80 □l and add 20 □l-50 ng/□l of MLV_pD (pro-pIVEX//pD-ter) or 20 □l-50 ng/□l of del_pD (pro-pIVEX//pD-ter) PCR mixture. Transcription was performed 3 hr at 37° C.
Both transcription mixtures were diluted to 200 μl with ice-cold nuclease-free water and 200 μl of 6 M LiCl solution were added. Mixtures incubated 30 min at +4° C. and centrifuged for 30 min at +4° C. in cooling centrifuge at max speed (25,000 g). Supernatant was discarded and RNA pellet washed with 500 μl of ice-cold 75% ethanol. Tubes again were centrifuged for 5 min at +4° C. in cooling centrifuge at max speed and supernatant was discarded. RNA pellet was dried for 12 min at room temperature and subsequently resuspended in 200 μl of nuclease-free ice-cold water by shaking for 15 min at +4° C. and 1400 rpm. Tubes again were centrifuged for 5 min at +4° C. in cooling centrifuge at max speed in order to separate not dissolved RNA. About 180 μl of supernatant were moved to new tube with 20 μl of 10× DNase I buffer (Mg 2+ ) (Fermentas); 1-1 u/μl DNasel (RNase-free) (Fermentas) and incubated for 20 min at +37° C. in order to degrade DNA. To each tube were added 20 μl of 3 M Sodium acetate pH 5.0 solution and 500 μl of ice-cold 96% ethanol. Finally RNA was precipitated by incubation for 30 min at −20° C. and centrifugation for 30 min at +4° C. in cooling centrifuge at max speed (25,000 g). Supernatant was discarded and RNA pellet washed with 500 μl of ice-cold 75% ethanol. Tubes again were centrifuged for 5 min at +4° C. in cooling centrifuge at max speed and supernatant was discarded. RNA pellet was dried for 12 min at room temperature and subsequently resuspended in 43 μl of nuclease-free ice-cold water by shaking for 15 min at +4° C. and 1400 rpm. RNA solution was aliqouted 4×10 μl and liquid nitrogen frozen. Concentration of mRNA was measured spectrophotometrically and double checked on agarose gel using RiboRuler™ RNA Ladder, High Range (Fermentas)—MLV_pD mRNA ˜1.2 μg/μl; del_pD mRNA ˜1.2 μg/μl.
Purified mRNA is mixed with ratio 1:50=MLV (active RT):del (inactive RT). MLV_pD mRNA was diluted 25 times to ˜48 ng/μl and 1 μl (˜48 ng) was mixed with 2 μl˜1.2 μg/μl del_pD mRNA (2.4 μg) giving mRNA mixture ˜0.8 μg/μl with ratio 1:50. In vitro translation was performed using two translation systems RTS100 E. coli HY Kit (03 186 148 001—Roche) and synthetic WakoPURE (295-59503—Wako). Proteins translation sequences are given in SEQ ID No: 6 for MLV_pD and SEQ ID No: 7 for del_pD.
Translation mixture for RTS HY system (25 μl): 6 μl— E. coli lysate (Roche); 5 μl—Reaction Mix (Roche); 6 μl—amino acids (Roche); 0.5 μl-100 mM Met (Roche); 0.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 0.4 μl-200 μM assrA oligonucleotide (SEQ ID No: 5); 0.25 μl-1 M DTT; 2.5 μl reconstitution buffer (Roche); 2.5 μl nuclease-free water and 1.5 μl-0.8 μg/μl mRNA mixture 1:50=MLV_pD:del_pD (˜1200 ng). In vitro translation was performed for 20 min at 30° C.
Translation mixture for WakoPURE system (25 μl): 12.5 μl—A solution (Wako); 5 μl—B solution (Wako); 0.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 0.4 μl-200 μM assrA oligonucleotide (SEQ ID No: 6); 0.25 μl-1 M DTT; 5 μl nuclease-free water and 1.5 μl-0.8 μg/μl mRNA mixture 1:50=MLV_pD:del_pD (˜1200 ng). In vitro translation was performed for 30 min at 37° C.
Both translations (˜25 μl) were stopped by adding 155 μl of ice-cold stopping buffer WBK 500 +DTT+triton (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—triton x-100 (T8787—Sigma)) and centrifuged for 5 min at +4° C. and 25,000 g. Very carefully 160 μl of centrifuged translation mixture was pippeted on the top of 840 μl 35% (w/v) sucrose solution in WBK 500 +DTT+triton (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—triton x-100 (T8787—Sigma); 35% (w/v)—sucrose (84097—Fluka)). In order to purify ternary complexes (TC) of mRNA-ribosome-protein (tRNA) ultracentrifugation was performed using TL-100 Beckman ultracentrifuge; TLA100.2 fixed angle rotor (Beckman); transparent 1 ml ultracentrifugation tubes (343778—Beckman) for 9 min at +4° C. and 100,000 rpm. In order to keep small transparent pellet of TC at the bottom of ultracentrifugation tube intact tubes were handled with care. Initially 750 μl of solution was removed from the very top of the centrifugation tube. Then (very carefully) tube walls were washed with 750 μl of WBK 500 (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl). Finally all solution was removed starting from the very top of the centrifugation tube and pellet was dissolved in 30 μl of ice-cold stopping buffer WBK 500 +DTT+triton (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—triton x-100 (T8787—Sigma)).
As it was determined using radioactively labeled mRNA after ultracentrifugation 5%-30% of input mRNA is located in ternary complex pellet. Therefore it was expected to have less than 360 ng (30% from 1200 ng mRNA used in translation reaction) of mRNA in 30 μl of buffer (˜12 ng/μl or 9*10 9 molecules/μl of ternary complex).
Reverse transcription reaction mixture for selection was prepared on ice: 60 μl-5× reaction buffer for Reverse Transcriptase (Fermentas); 7.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 15 μl-20 μM pD — 42 oligonucleotide (SEQ ID No: 8); 188 μl nuclease-free water-mixture divided into two tubes 2×135 □l and 0.9 μl of purified (<8*10 9 molecules) TC (translation in Roche—RTS HY kit) or 0.9 μl of purified (<8*10 9 molecules) TC (translation in Wako—WakoPURE) were added. Each reaction mixture (˜135 μl) again was divided into two tubes 45 μl. and 90 μl. To the first part—45 μl of RT mixture 5 μl of nuclease-free water were added. This sample is considered to be the negative selection control (without dNTP) and has to prove that there is no DNA contamination in the reaction mixture and cDNA synthesis is strictly linked to reverse transcriptase functional activity coming from MLV RT in ternary complex. To the second part—90 μl of RT mixture 10 μl-10 mM each dNTP Mix (Fermentas) were added and reaction mixture again was divided into two tubes—50 μl for selection control and 50 μl supplemented with 1 μl-200 u/μl of RevertAid H-M-MuLV Reverse Transcriptase (Fermentas) for positive selection control. According to the protocol each reverse transcription reaction mix contains <2.7*10 9 molecules of ternary complex in 50 μl volume.
Oil-surfactant mixture for emulsification was prepared by mixing ABIL EM 90 (Goldschmidt) into mineral oil (M5904—Sigma) to final concentration of 4% (v/v) (Ghadessy and Holliger, 2004; US2005064460). Emulsions were prepared at +4° C. in 5 ml cryogenic vials (430492—Corning) by mixing 950 μl of oil-surfactant mixture with 50 μl of RT mixture. Mixing was performed using MS-3000 magnetic stirrer with speed control (Biosan) at ˜2100 rpm; Rotilabo®—(3×8 mm) magnetic followers with center ring (1489.2—Roth); water phase was added by 10 μl aliquots every 30 sec, continuing mixing for 2 more minutes (total mixing time—4 min). According to optical microscopy data compartments in our emulsions vary from 0.5 μm to 10 μm in size with average diameter of ˜2 μM. Therefore it was expected to have ˜1′10 10 water in oil compartments after the emulsification of 50 μl reverse transcription reaction mixture, which contains less than 2.7*10 9 molecules of ternary complex (about 1 mRNA and reverse transcriptase molecules per 3-4 compartments).
All six emulsions representing RT reactions with TC, translation in Roche—RTS HY kit (negative selection control, selection control and positive selection control) and with TC, translation in Wako—WakoPURE (negative selection control, selection control and positive selection control) were incubated 1 hr at +42° C.
To recover the reaction mixtures emulsions were moved to 1.5 ml tube, centrifuged for 1-min at room temperature and 25,000 g. Oil phase was removed leaving concentrated (but still intact) emulsion at the bottom of the tube and 250 μl of PB buffer (Qiagen PCR purification kit) were added. Finally emulsions were broken by extraction with 0.9 ml water-saturated ether; 0.9 ml water-saturated ethyl-acetate (in order to remove ABIL EM 90 detergent) and again 0.9 ml water-saturated ether. Water phase was dried for 5 min under vacuum at room temperature. Synthesized cDNA was purified with Qiagen PCR purification kit and eluted in 30 μl of EB buffer (Qiagen PCR purification kit).
Amplification of cDNA was performed by nested PCR. Initial PCR mixture was prepared on ice: 16 μl-10× Taq buffer with KCl (Fermentas); 16 μl-2 mM of each dNTP (Fermentas); 9.6 μl-25 mM MgCl 2 (Fermentas); 3.2 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 0.8 μl-100 μM RD_Nde primer (SEQ ID No: 9); 0.8 μl-100 μM pD — 55 primer (SEQ ID No: 10); 74 μl water-mixture was divided into 6 samples×15 μl (6×15 μl) and 30 μl. To 6×15 μl of PCR master mix were added 5 μl of cDNA (1-6 RT samples); to 30 μl of PCR master mix were added 9 μl water and mixture again divided into two tubes 2×19.5 μl for negative PCR control (plus 0.5 μl water) and positive PCR control (plus 0.5 μl-1:1 mixture (˜1 ng) of pET_his_MLV_pD and pET_his_del_pD plasmids). The cycling protocol was: initial denaturation step 3 min at 94° C., 25 cycles (45 sec at 94° C., 45 sec at 58° C., and 2 min at 72° C.) and final elongation 5 min at 72° C. Expected length of PCR fragments was 2185 bp for MLV_pD and 2014 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well ( FIG. 3 ).
Nested PCR was performed using two different sets of primers, giving either partial gene amplification (for better resolution of MLV:del cDNA ratio in RT samples) or full gene amplification (to prove possibility of full gene recovery).
Nested PCR mixture for partial gene amplification was prepared on ice: 28 μl-10× Taq buffer with KCl (Fermentas); 28 μl-2 mM of each dNTP (Fermentas); 16.8 μl-25 mM MgCl 2 (Fermentas); 5.6 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1.4 μl-100 μM M_F primer (SEQ ID No: 11); 1.4 μl-100 μM M — 2R primer (SEQ ID No: 12); 185 μl water-mixture divided 2×19 μl and 6×38 μl. To 2×19 μl of PCR master mix was added 1 μl of positive or negative controls of first PCR (primers set RD_Nde//pD — 55)-30 PCR cycles amplification; to 6×38 μl of PCR master mix were added 2 μl of first PCR (primers set RD_Nde//pD — 55) (1-6 samples)—each sample again was divided into two 2×20 μl for 23 or 30 PCR cycles amplification. The cycling protocol was: initial denaturation step 3 min at 94° C., 23 or 30 cycles (45 sec at 94° C., 45 sec at 57° C., and 1 min at 72° C.) and final elongation 5 min at 72° C. Expected length of PCR fragments was 907 bp for MLV_pD and 736 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well ( FIG. 4 ).
Nested PCR mixture for full gene amplification was prepared on ice: 28 μl-10× Taq buffer with KCl (Fermentas); 28 μl-2 mM of each dNTP (Fermentas); 16.8 μl-25 mM MgCl 2 (Fermentas); 5.6 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1.4 μl-100 μM M_Esp primer (SEQ ID No: 13); 1.4 μl-100 μM M_Eri primer (SEQ ID No: 14); 185 μl water-mixture divided 2×19 μl and 6×38 W. To 2×19 μl of PCR master mix was added 1 μl of positive or negative controls of first PCR (primers set RD_Nde//pD — 55)-30 PCR cycles amplification; to 6×38 μl of PCR master mix were added 2 μl of first PCR (primers set RD_Nde//pD — 55) (1-6 samples)—each sample again was divided into 2×20 μl for 23 or 30 PCR cycles amplification. The cycling-protocol was: initial denaturation step 3 min at 94° C., 23 or 30 cycles (45 sec at 94° C., 45 sec at 55° C., and 2 min at 72° C.) and final elongation 5 min at 72° C. Expected length of PCR fragments was 2077 bp for MLV_pD and 1906 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well ( FIG. 5 ).
Results
To demonstrate proof of principle for Compartmentalized Ribosome Display (CRD) method selection was performed using starting 1:50=MLV:del mixture of two mRNA encoding active (MLV) and inactive (del) reverse transcriptases fused to protein D spacer ( FIG. 1 ). In vitro translation was performed using two different translation systems Roche—RTS 100 E. coli HY or Wako—WakoPURE in order to understand which translation system is better in our experimental setup. For each translation system three compartmentalized RT reactions were performed: negative selection control without dNTP, which has to prove that there is no DNA contamination in the reaction mixture; selection control, which has to demonstrate the enrichment of genes encoding active (MLV) reverse transcriptase over genes encoding inactivated enzyme (del), because only active enzyme can synthesize cDNA; and positive selection control supplemented with external RevertAid H-commercial reverse transcriptase, which has to serve as positive RT control synthesizing cDNA from both MLV_pD and del_pD mRNA in all compartments, showing real ratio of genes in reaction mixture without selection pressure applied.
Synthesyzed cDNA was amplified by nested PCR. The picture of agarose gel electrophoresis of initial PCR (25 cycles) ( FIG. 3 ) shows weak PCR fragments bands only in case of both positive selection controls (translation systems—Roche and Wako). This is normal, because these samples contain external RT enzyme, which synthesizes cDNA much more efficiently comparing to reactions containing only one in vitro synthesized reverse transcriptase molecule per compartment.
The picture of agarose gel electrophoresis of nested PCR (partial gene amplification) is shown in FIG. 4 . Amplification results after 23 and 30 PCR cycles are consistent:
1) there is no amplification (no DNA contamination) in negative selection controls (w/o dNTP); 2) very efficient amplification of delpD cDNA (736 bp DNA fragment) is observed in positive selection controls (external RT enzyme) and no MLV_pD cDNA amplification is visible, because initial ratio of MLV_pD to del_pD mRNA is 1:50; 3) amplification of both cDNA MLV_pD (907 bp DNA fragment) and del_pD (736 bp DNA fragment) are observed in case of selection controls; 4) ratio of MLV_pD:del_pD˜1:1 is observed in case of reverse transcriptase synthesized by Roche in vitro translation system, what means ˜50 times enrichment of MLV_pD genes over del_pD genes starting from initial 1:50 ratio; 5) ratio of MLV_pD:del_pD˜1:3 is observed in case of reverse transcriptase synthesized by Wako in vitro translation system, what means ˜16 times enrichment of MLV_pD genes over del_pD genes starting from initial 1:50 ratio.
The picture of agarose gel electrophoresis of nested PCR (full gene amplification) is shown in FIG. 5 . Amplification results after 23 and 30 PCR cycles are consistent in between and comparing to results of nested PCR used for partial gene amplification ( FIG. 5 ):
1) there is no amplification (no DNA contamination) in negative selection controls (w/o dNTP); 2) very efficient amplification of del_pD cDNA (1906 bp DNA fragment) is observed in positive selection controls (external RT enzyme) and no MLV_pD cDNA amplification is visible, because initial ratio of MLV_pD to del_pD mRNA is 1:50; 3) amplification of both cDNA MLV_pD (2077 bp DNA fragment) and del_pD 1906 bp DNA fragment) are observed in case of selection controls; 4) it is difficult to determine ratio of MLV_pD:del_pD in case of full gene amplification, because relative difference between 2077 bp (MLV_pD) and 1906 bp (del_pD) DNA fragments is not big enough, but in general ratios are similar to results of nested PCR used for partial gene amplification.
As a result of this example we can conclude that during reverse transcription reaction performed in CRD format we have enriched genes encoding active MLV reverse transcriptase over the genes encoding inactive enzyme by a factor of 50 in case of Roche translation system or by a factor of 16 in case of Wako translation system used to synthesize enzymes in vitro.
Example 2
CRD—Selection for Reverse Transcriptase, which Shows Improved Performance at Higher Temperatures
In order to understand, how efficiently Compartmentalized Ribosome Display (CRD) selection works, evolution experiment of Moloney Murine Leukemia Virus reverse transcriptase (M-MuLV RT) was performed. General scheme of experiment is shown in FIG. 6 . Initial mutants library of reverse transcriptase was constructed by error-prone PCR using nucleotide analogues dPTP and 8-oxo-dGTP. Whole gene (˜2 kb) mutagenesis was performed introducing 2-3 nucleotides or 1-2 amino acids mutations per gene. PCR fragment encoding mutants library of reverse transcriptase (in fusion with protein D) MLV_pD was used to synthesize mRNA. Purified mRNA was used for in vitro translation reaction. Ternary complexes (TC) of mRNA-ribosome-MLV_pD (tRNA) were formed in translation mixture and stabilized by low temperature and high concentration of Mg 2+ ions. Mixture of TC was purified by ultracentrifugation on sucrose cushions. Precipitated TC was dissolved in ice-cold buffer (50 mM Mg 2+ ) and used to prepare reverse transcription reaction mix supplemented with external dNTP set and primer for RT reaction. Ice-cold RT reaction mixture was emulsified giving ˜1*10 10 water in oil compartments ˜2 μm in size. Optimal reaction temperature of MLV RT is ˜42° C. In order to select for reverse transcriptase variants, which are working better at higher temperatures emulsified RT reaction mixture (less than one TC (mRNA+MLV RT) per compartment) was incubated for 1 hr at 50° C. At this temperature successful synthesis of full length cDNA was performed better in compartments containing more active or thermostable MLV reverse transcriptase variants. Subsequent PCR was used to amplify full length cDNA and enrichment for more active and thermostable reverse transcriptase genes was performed. By PCR amplified genes were moved back to CRD format restoring intact 5′ (START fragment—T7 polymerase promoter, SD and his-tag coding sequences) and 3′ (END fragment—gs linker, protein D and second gs linker) sequences by ligation-PCR.
Reconstructed PCR fragment, containing enriched library of reverse transcriptase genes, was used for subsequent mRNA transcription and next CRD selection round. Each selection round was performed at higher and higher temperatures of RT reaction: 50° C. (1 st round); 52.5° C. (2 nd round); 55° C. (3 rd round); 57.5° C. (4 th round) and 60° C. (5 th round).
Amplified library of reverse transcriptase genes (without C terminal pD linker) after 5 th selection round was cloned into plasmid vector. Individual clones were sequenced and analyzed. Pool of evolved proteins as well as individual mutants were purified via his-tag using affinity chromatography. MLV reverse transcriptase specific activities at 37° C., 50° C. and residual activity at 37° C. after 5 min enzyme incubation at 50° C. were determined.
Methods and Materials
Initial plasmid pET_his_MLV_pD (SEQ ID No: 1 and FIG. 2 ) was used as a starting material for error-prone PCR. Mutations were introduced using nucleotide analogues dPTP and 8-oxo-dGTP. PCR mixture for error prone PCR was prepared on ice: 10 μl-10× Taq buffer with KCl (Fermentas); 10 μl-2 mM of each dNTP (Fermentas); 6 μl-25 mM MgCl 2 (Fermentas); 2 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 0.5 μl-100 μM M_Esp primer (SEQ ID No: 13); 0.5 μl-100 μl M_Eri primer (SEQ ID No: 14); 1-10 μM dPTP (TriLink BioTechnolgies); 5 μl-100 μM 8-oxo-dGTP (TriLink BioTechnolgies); 3.75 μl-40 ng/μl (totally 150 ng) of pET_his_MLV_pD plasmid; 61.25 μl water. The cycling protocol was: initial denaturation step 3 min at 94° C., 30 cycles (30 sec at 94° C., 30 sec at 55° C., and 2 min at 72° C.) and final elongation 5 min at 72° C. Amplification was 150-300 fold from 150 ng of plasmid (7873 bp) target to ˜6-12 μg of amplified product (2077 bp PCR fragment for pET_his_MLV_pD). PCR fragment was purified using Qiagen PCR purification kit, digested with Esp3I (recognition sequence CGTCTC (1/5)) and EcoRI (recognition sequence G↓AATTC) and finally purified from agarose gel using Qiagen Gel extraction kit giving DNA concentration ˜50 ng/μl.
Mutagenesis efficiency and library quality was checked by sequencing of individual clones subcloned back into original pET_his_MLV_pD plasmid digested with NcoI and EcoRI. As it was expected mutations were distributed randomly all over the amplified sequence of MLV RT gene (Appendix 1). Among 10 sequenced genes 23 nucleotide mutations (1 transversion, 20 transitions, 2 deletions—labelled red in Appendix 1) were found giving 15 amino acids exchanges, 6 silent mutations, 1 stop codon and 2 frame shifts of coding frame—on average 1-2 amino acids substitutions per gene.
Mutated library was ligated with START (244 bp) and END (398 bp) fragments in order to get PCR fragment suitable for CRD selection ( FIG. 7 ). START fragment (containing T7 polymerase promoter, SD and his-tag coding sequences) was constructed by PCR amplification of initial 983 bp START fragment (target—plasmid pET_his_del_pD (SEQ ID No: 2), primers—pro-pIVEX (SEQ ID No: 3) and M — 1R (SEQ ID No: 15)) and subsequent digestion with NcoI (recognition sequence C↓CATGG) giving 244 bp DNA fragment. END fragment (containing gs linker, protein D and second gs linker sequences) was constructed by PCR amplification of initial 1039 bp END fragment (target—plasmid pET_his_del_pD (SEQ ID No: 2), primers—M — 3F (SEQ ID No: 16) and pD-ter (SEQ ID No: 4)) and subsequent digestion with EcoRI (recognition sequence G↓AATTC) giving 398 bp DNA fragment.
Ligation reaction (150 μl) was prepared at room temperature: 15 μl-10× ligation buffer for T4 DNA Ligase (Fermentas); 15 μl-1 u/μl T4 DNA ligase (Fermentas); 26 μl-50 ng/μl mutated MLV RT library digested with Esp3I (NcoI compatible end) and EcoRI (˜1300 ng or ˜5.9*10 11 molecules); 9.4 μl-35 ng/μl START fragment digested with NcoI (˜329 ng or ˜1.2*10 12 molecules); 15.7 μl-35 ng/μl END fragment digested with EcoRI (˜548 ng or ˜1.2*10 12 molecules); 68.9 μl-water. Ligation was performed overnight at +4° C. Reaction mixture was treated once with phenol and twice with chloroform, precipitated and dissolved in 53 μl of water. Approximate ligation yield ˜20% was determined comparing amplification efficiency of ligation mixture and known amount of plasmid pET_his_MLV_pD. Taking into account 20% ligation yield diversity of MLV RT mutants library was defined as ˜1.2*10 11 molecules (50 μl).
Ligated MLV RT library was amplified by PCR (1 ml—prepared on ice): 100 μl-10× Taq buffer with KCl (Fermentas); 100 μl-2 mM of each dNTP (Fermentas); 60 μl-25 mM MgCl 2 (Fermentas); 80 μl—DMSO (08418—Sigma); 20 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 5 μl-100 μM pro-pIVEX primer (SEQ ID No: 3); 5 μl-100 μM pD-ter—primer (SEQ ID No: 17); 20 μl—ligated MLV RT library (˜5*10 10 molecules); 610 μl—water. The cycling protocol was: initial denaturation step 3 min at 94° C., 15 cycles (30 sec at 94° C., 30 sec at 53° C., and 3 min at 72° C.) and final elongation 5 min at 72° C. Amplification was ˜200 fold from ˜5*10 10 molecules (corresponds to ˜150 ng) of final ligation fragment 2702 bp in size target to ˜30 μg (30 ng/μl) of amplified product (2702 bp PCR fragment).
1 st Selection Round
Transcription mixture (100 μl) was prepared: 20 □l-5×T7 transcription buffer (1 M HEPES-KOH pH 7.6; 150 mM Mg acetate; 10 mM spermidin; 0.2 M DTT); 28 □l-25 mM of each NTP (Fermentas); 4 □l-20 u/□l T7 RNA polymerase-(Fermentas); 2 □l-40 u/□l RiboLock RNase inhibitor (Fermentas); 30 □l-30 ng/□l of mutants library (pro-pIVEX//pD-ter-) PCR mixture (˜900 ng or ˜3*10 11 molecules); 16 □l nuclease-free water. Transcription was performed 3 hr at 37° C. (library diversity ˜5*10 10 molecules).
Transcription mixture was diluted to 200 μl with ice-cold nuclease-free water and 200 μl of 6 M LiCl solution were added. Mixture incubated 30 min at +4° C. and centrifuged for 30 min at +4° C. in cooling centrifuge at max speed (25,000 g). Supernatant was discarded and RNA pellet washed with 500 μl of ice-cold 75% ethanol. Tube again was centrifuged for 5 min at +4° C. in cooling centrifuge at max speed and supernatant was discarded. RNA pellet was dried for 12 min at room temperature and subsequently resuspended in 200 μl of nuclease-free ice-cold water by shaking for 15 min at +4° C. and 1400 rpm. Tube again was centrifuged for 5 min at +4° C. in cooling centrifuge at max speed in order to separate not dissolved RNA. About 180 μl of supernatant were moved to new tube with 20 μl of 10× DNase I buffer (Mg 2+ ) (Fermentas); 1-1 u/μl DNasel (RNase-free) (Fermentas) and incubated for 30 min at +37° C. in order to degrade DNA. To reaction mixture were added 20 μl of 3 M Sodium acetate pH 5.0 solution and 500 μl of ice-cold 96% ethanol. Finally RNA was precipitated by incubation for 30 min at −20° C. and centrifugation for 30 min at +4° C. in cooling centrifuge at max speed (25,000 g). Supernatant was discarded and RNA pellet washed with 500 μl of ice-cold 75% ethanol. Tube again was centrifuged for 5 min at +4° C. in cooling centrifuge at max speed and supernatant was discarded. RNA pellet was dried for 12 min at room temperature and subsequently resuspended in 33 μl of nuclease-free ice-cold water by shaking for 10 min at +4° C. and 1400 rpm. RNA solution was aliqouted 3×10 μl and liquid nitrogen frozen. Concentration of mRNA was measured spectrophotometrically and double checked on agarose gel using RiboRuler™ RNA Ladder, High Range (Fermentas)-MLV RT library mRNA ˜2.1 μg/μl.
In vitro translation was performed using RTS 100 E. coli HY (03 186 148 001—Roche) translation system (25 μl): 6 μl— E. coli lysate (Roche); 5 μl—Reaction Mix (Roche); 6 μl—amino acids (Roche); 0.5 μl-100 mM Met (Roche); 0.5 μl-40 u/1:11 RiboLock RNase inhibitor (Fermentas); 0.4 μl-200 μM assrA oligonucleotide (SEQ ID No: 5); 0.25 μl-1 M DTT; 3 μl reconstitution buffer (Roche); 2.5 μl nuclease-free water and 0.6 μl-2.1 μg/μl mRNA (˜1200 ng). Reaction mixture was incubated for 20 min at 30° C. Translation was stopped adding 155 μl of ice-cold stopping buffer WBK 500 +DTT+triton (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—triton x-100 (T8787—Sigma)) and centrifuged for 5 min at +4° C. and 25,000 g. Very carefully 160 μl of centrifuged translation mixture was pippeted on the top of 840 μl 35% (w/v) sucrose solution in WBK 500 +DTT+triton (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—triton x-100 (T8787—Sigma); 35% (w/v)—sucrose (84097—Fluke)). In order to purify ternary complexes (TC) of mRNA-ribosome-MLV (tRNA) ultracentrifugation was performed using TL-100 Beckman ultracentrifuge; TLA100.2 fixed angle rotor (Beckman); transparent 1 ml ultracentrifugation tubes (343778—Beckman) for 9 min at +4° C. and 100,000 rpm. In order to keep small transparent pellet of TC at the bottom of ultracentrifugation tube intact tubes were handled with care. Initially 750 μl of solution was removed from the very top of the centrifugation tube. Than (very carefully) tube walls were washed with 750 μl of WBK 500 (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl). Finally all solution was removed starting from the very top of the centrifugation tube and pellet was dissolved in 30 μl of ice-cold stopping buffer WBK 500 +DTT+triton (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—triton x-100 (T8787—Sigma)).
As it was determined experimentally, using radioactively labeled mRNA, ultracentrifugation yields 5%-30% of input mRNA in ternary complex pellet. Therefore it was expected to have less than 360 ng (30% from 1200 ng mRNA used in translation reaction) of mRNA in 30 μl of buffer (˜12 ng/μl or 9*10 9 molecules/μl of ternary complex).
Reverse transcription reaction mixture for selection was prepared on ice: 60 μl-5× reaction buffer for Reverse Transcriptase (Fermentas); 7.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 15 μl-20 μM pD — 42 oligonucleotide (SEQ ID No: 8); 186 μl nuclease-free water and 1.8 μl of purified (<1.8*10 10 molecules) TC (translation in Roche—RTS HY kit). Reaction mixture was divided into two tubes 45 μl and 225 μl. To first part—45 μl of RT mixture were added 5 μl of nuclease-free water. This sample was considered to be negative selection control (without dNTP) and has to prove that there is no DNA contamination in the reaction mixture and cDNA synthesis is strictly linked to reverse transcriptase functional activity coming from MLV RT in ternary complex. To second part—225 μl of RT mixture were added 25 μl-10 mM each dNTP Mix (Fermentas) and reaction mixture again was divided into two tubes −200 μl (4×50 μl) for selection control (<1.2*10 10 molecules of TC totally) and 50 μl supplemented with 1 μl-200 u/μl of RevertAid H-M-MuLV Reverse Transcriptase (Fermentas) for positive selection control. According to protocol each reverse transcription reaction mix contains <3*10° molecules of ternary complex in 50 μl volume.
Oil-surfactant mixture for emulsification was prepared by mixing ABIL EM 90 (Goldschmidt) into mineral oil (M5904—Sigma) to final concentration of 4% (v/v) (Ghadessy and Holliger, 2004; US2005064460). Emulsions were prepared at +4° C. in 5 ml cryogenic vials (430492—Corning) by mixing 950 μl of oil-surfactant mixture with 50 μl of RT mixture. Mixing was performed using MS-3000 magnetic stirrer with speed control (Biosan) at ˜2100 rpm; Rotilabo®—(3×8 mm) magnetic followers with centre ring (1489.2—Roth); water phase was added by 10 μl aliquots every 30 sec, continuing mixing for 2 more minutes (total mixing time—4 min). According to optical microscopy data compartments in our emulsions vary from 0.5 μm to 10 μm in size with average diameter of ˜2 μm. Therefore it was expected to have ˜1′10 10 water in oil compartments after the emulsification of 50 μl reverse transcription reaction mixture, which contains less than 3*10 9 molecules of ternary complex (about 1 mRNA and reverse transcriptase molecules per 3-4 compartments).
All emulsions were incubated 1 hr at +50° C. in order to select for reverse transcriptase variants, which work better at higher temperatures. To recover the reaction mixtures emulsions were moved to 1.5 ml tube, centrifuged for 10 min at room temperature and 25,000 g. Oil phase was removed leaving concentrated (but still intact) emulsion at the bottom of the tube. Emulsions were broken by extraction with 0.9 ml water-saturated ether, 0.9 ml water-saturated ethyl-acetate (in order to remove ABIL EM 90 detergent) and again 0.9 ml water-saturated ether. Water phase was dried for 5 min under vacuum at room temperature and 250 μl of PB buffer (Qiagen PCR purification kit) were added. Four selection samples were merged into two tubes. Synthesized cDNA was further purified with Qiagen PCR purification kit and eluted in 30 μl of EB buffer (Qiagen PCR purification kit) in case of negative and positive selection controls and 2×30 μl in case of selection control.
Amplification of cDNA was performed by nested PCR. First of all small PCR amplification was performed in order to check negative and positive selection controls and determine minimal number of PCR cycles required for efficient amplification of cDNA in selection samples. PCR mixture (200 μl) was prepared on ice: 20 μl-10× Taq buffer with KCl (Fermentas); 20 μl-2 mM of each dNTP (Fermentas); 12 μl-25 mM MgCl 2 (Fermentas); 2.5 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1-2.5 u/μl Pfu DNA Polymerase (Fermentas); 1-100 μM RD_Nde primer (SEQ ID No: 9); 1 μl-100 μM pD — 55 primer (SEQ ID No: 10); 50 μl—purified cDNA of selection controls; 92 μl water. The cycling protocol for 2185 bp PCR fragment was: initial denaturation step 3 min at 94° C., 25 cycles (45 sec at 94° C., 45 sec at 58° C., and 2 min at 72° C.) and final elongation 5 min at 72° C.
Nested PCR mixture (500 μl) for full gene amplification was prepared on ice: 50 μl-10× Taq buffer with KCl (Fermentas); 50 μl-2 mM of each dNTP (Fermentas); 30 μl-25 mM MgCl 2 (Fermentas); 6.25 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 2.5 μl-2:5 u/μ1 Pfu DNA Polymerase (Fermentas); 2.5 μl-100 μM M_Esp primer (SEQ ID No: 13); 2.5 μl-100 μM M_Eri primer (SEQ ID No: 14); 50 μl of first PCR (primers-set RD_Nde//pD — 55); 306 μl water. The cycling protocol for 2077 bp PCR fragment was: initial denaturation step 3 min at 94° C., 22 cycles (45 sec at 94° C., 45 sec at 55° C., and 2 min at 72° C.) and final elongation 5 min at 72° C.
Final PCR fragment of selection sample was agarose-gel purified using Qiagen gel extraction kit (elution in 60 μl˜50 ng/μl). Purified PCR fragment was digested with EcoRI and Esp3I for 1 hr at 37° C. and again agarose-gel purified (elution in 30 μl˜50 ng/μl).
Recovered MLV reverse transcriptase library after 1 st selection round was ligated with START and END fragments (construction described earlier in this example) in order to get PCR fragment ( FIG. 7 ) suitable for 2 nd round of CRD selection ( FIG. 6 ). Ligation reaction (40 μl) was prepared at room temperature: 4 μl-10× ligation buffer for T4 DNA Ligase (Fermentas); 2 μl-1 u/μl T4 DNA ligase (Fermentas); 4 μl-50 ng/μl selected library digested with Esp3I and EcoRI (˜200 ng or ˜0.9*10 11 molecules); 1.1 μl-35 ng/μl START fragment digested with NcoI (˜35 ng or ˜1.5*10 11 molecules); 1.76 μl-35 ng/μl END fragment digested with EcoRI (˜61 ng or ˜1.5*10 11 molecules); 27.2 μl-water. Ligation was performed 1 hr at room temperature.
Ligated MLV RT library was amplified by PCR (300 μl—prepared on ice): 30 μl-10× Taq buffer with KCl (Fermentas); 30 μl-2 mM of each dNTP (Fermentas); 18 μl-25 mM MgCl 2 (Fermentas); 24 μl—DMSO (D8418—Sigma); 3.7 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1.5 μl-2.5 u/μl Pfu DNA Polymerase (Fermentas); 1.5 μl-100 μM pro-pIVEX primer (SEQ ID No: 3); 1.5 μl-100 μM pD-ter-primer (SEQ ID No: 17); 25.5 μl—ligated MLV RT library (<0.6*10 10 molecules); 164.3 μl-water. The cycling protocol for 2702 bp PCR fragment was: initial denaturation step 3 min at 94° C., 15 cycles (45 sec at 94° C., 45 sec at 53° C., and 3 min at 72° C.) and final elongation 5 min at 72° C. PCR fragment was agarose-gel purified using Qiagen gel exraction kit (elution in 30 μl˜100 ng/μl).
2 nd Selection Round
Second selection round was performed following general setup of 1° selection round of experimental scheme with minor modifications in PCR cycles, emulsified RT reaction temperature and few more details.
All modifications are given below:
transcription—10 μl-100 ng/μl (˜1000 ng) of agarose-gel purified PCR fragment were taken; final concentration of mRNA used in 2 nd selection round was 1.5 μg/μl; translation—0.8 μl (˜1.2 μg) of mRNA were taken; emulsified RT reaction was performed 1 hr at 52.5° C.; 1 st PCR (RD_Nde//pD — 55)—24 cycles were performed; 2 nd (nested) PCR (M_Esp//M_Eri)—23 cycles were performed; final concentration of digested PCR fragment—80 ng/μl; ligation—200 ng (˜0.9*10 11 molecules) of MLV RT library were taken; PCR (on ligation mix)—<0.6*10 10 molecules of selected library were taken and 15 PCR cycles were performed; concentration of final agarose-gel purified PCR fragment was 200 ng/μl.
3 rd Selection Round
Third selection round was performed following general setup of 1 st selection round of experimental scheme with minor modifications in PCR cycles, emulsified RT reaction temperature and few more details.
All modifications are given below:
transcription—5 μl-200 ng/μl (˜1000 ng) of agarose-gel purified PCR fragment were taken; final concentration of mRNA used in 3 rd selection round was 1.5 μg/μl; translation—0.8 μl-1.5 μg/μl (˜1.2 μg) of mRNA were taken; emulsified RT reaction was performed 1 hr at 55° C.; 1 st PCR (RD_Nde//pD — 55)—25 cycles were performed; 2 nd (nested) PCR (M_Esp//M_Eri)—22 cycles were performed; final concentration of digested PCR fragment—70 ng/μl; ligation—200 ng (˜0.9*10 11 molecules) of MLV RT library were taken; PCR (on ligation mix)—<0.6*10 10 molecules of selected library were taken and 15 PCR cycles were performed; concentration of final agarose-gel purified PCR fragment was 100 ng/μl.
4 th Selection Round
Fourth selection round was performed following general setup of 1 st selection round of experimental scheme with minor modifications in PCR cycles, emulsified RT reaction temperature and few more details.
All modifications are given bellow:
transcription—10 μl-100 ng/μl (˜1000 ng) of agarose-gel purified PCR fragment were taken; final concentration of mRNA used in 4 th selection round was 1.8 μg/μl; translation—0.67 μl-1.8 μg/μl (˜1.2 μg) of mRNA were taken; emulsified RT reaction was performed 1 hr at 57.5° C.; 1 st PCR (RD_Nde//pD — 55)—25 cycles were performed; 2 nd (nested) PCR (M_Esp//M_Eri)—24 cycles were performed; final concentration of digested PCR fragment—50 ng/μl; ligation—200 ng (˜0.9*10 11 molecules) of MLV RT library were taken; PCR (on ligation mix)—<0.6*10 10 molecules of selected library were taken and 15 PCR cycles were performed; concentration of final agarose-gel purified PCR fragment was 100 ng/μl.
5 th Selection Round
Fifth selection round was performed following general setup of 1 st selection round of experimental scheme with some modifications in PCR cycles, emulsified RT reaction temperature and final stage of analysis.
All modifications are given bellow:
transcription—10 μl-100 ng/μl (˜1000 ng) of agarose-gel purified PCR fragment were taken; final concentration of mRNA used in 5 th selection round was 1.1 μg/μl; translation—1.1 μl-1.1 μg/μl (˜1.2 μg) of mRNA were taken; emulsified RT reaction was performed 1 hr at 60° C.; 1 st PCR (RD_Nde//pD — 55)—25 cycles were performed; 2 nd (nested) PCR (M_Esp//M_Eri)—33 cycles were performed;
Nested PCR mixture (500 μl) for full gene amplification was prepared on ice: 50 μl-10× Taq buffer with KCl (Fermentas); 50 μl-2 mM of each dNTP (Fermentas); 30 μl-25 mM MgCl 2 (Fermentas); 6.25 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 2.5 μl-2.5 u/μl Pfu DNA Polymerase (Fermentas); 2.5 μl-100 μM M_Esp primer (SEQ ID No: 13); 2.5 μl-100 μM M_Hind3+ primer (SEQ ID No: 18); 50 μl of first PCR (primers set RD_Nde//pD — 55); 306 μl water. The cycling protocol for 2077 bp PCR fragment was: initial denaturation step 3 min at 94° C., 22 cycles (45 sec at 94° C., 45 sec at 55° C., and 3 min at 72° C.) and final elongation 5 min at 72° C.
Final PCR fragment of selection sample was agarose-gel purified using Qiagen gel extraction kit (elution in 60 μl˜60 ng/μl). Purified PCR fragment was digested with HindIII and Esp3I for 1 hr at 37° C. and again agarose-gel purified (elution in 40 μl˜50 ng/μl).
Recovered MLV reverse transcriptase library after 5 th selection round was ligated into plasmid vector prepared from pET_his_MLV_pD (SEQ ID No: 1 and FIG. 2 ) digested with NcoI and HindIII, giving new 7474 bp plasmid pET_his_MLV (SEQ ID No: 19) encoding MLV RT with N-terminal his-tag and no pD fusion on C-terminus for fast protein purification using affinity chromatography.
Ligated MLV RT library after 5 th selection round was electroporated into T7 expression strain ER2566. Individual clones were sequenced and analyzed. Pool of evolved proteins as well as individual mutants and primary wt M-MuLV reverse transcriptase in the same construction were grown in 200 ml of LB to A590 ˜0.7 and purified via his-tag by affinity chromatography using 2 ml of Qiagen-Ni-NTA Superflow resin (all purification was performed under native conditions according to suppliers recommendations). Elution was performed in 1 ml of EB (50 mM—NaH 2 PO 4 , 300 mM—NaCl, 250 mM—imidazol, pH 8.0, 10 mM—β-mercaptoethanol and 0.1% of triton X-100). All proteins were dialyzed against 50 times excess of storage buffer (50 mM Tris-HCl (pH 8.3 at 25° C.), 0.1 M NaCl, 1 mM EDTA, 5 mM DTT, 0.1% (v/v). Triton X-100 and 50% (v/v) glycerol). Protein purity was checked on SDS-PAGE (usually ˜40-80% of target protein). Protein concentration was determined using Bredford method based Bio-Rad protein assay (500-0006).
MLV reverse transcriptase specific activities were measured at 37° C., 50° C. (enzyme diluted in special dilution buffer: 30 mM Tris-HCl pH 8.3 at 25° C., 10 mM DTT, 0.5 mg/ml BSA) and rest of activity at 37° C. after 5 min enzyme incubation at 50° C. (enzyme diluted and its stability measured in 1×RT reaction buffer: 50 mM Tris-HCl pH 8.3 at 25° C., 4 mM MgCl 2 , 10 mM DU, 50 mM KCl). Enzyme activity in all cases was assayed in the following final mixture: 50 mM Tris-HCl (pH 8.3 at 25° C.), 6 mM MgCl 2 , 10 mM DTT, 40 mM KCl, 0.5 mM dTTP, 0.4 MBq/ml [3H]-dTTP, 0.4 mM polyA.oligo(dT) 12-18 . Activity units were determined measuring incorporation of dTMP into a polynucleotide fraction (adsorbed on DE-81) in 10 min at particular reaction temperature and comparing to known amounts of commercial enzyme.
Results
During analysis of selection data we have accumulated 104 sequences expressing full length M-MuLV reverse transcriptase. The total CLUSTALW alignment of all proteins (Appendix 2) is compiled without N terminal His tag in order to have the same numeration of amino acids as is usually used in literature. Wild type sequence denoted as MLV is always given as the first sequence. Mutations are marked using white font color in black background (Appendix 2). Amino acids positions, mutations of which somehow improve M-MuLV reverse transcriptase properties and are described in different patent applications are marked in the alignment as columns of amino acids (white font) highlighted in grey. Mutations originating from our selection and located in grey columns serve as proof that our selection procedure precisely targeted the beneficial hot spot or even exact amino acid mutations described elsewhere. Out of 104 sequenced clones we found 98 unique sequences and 1 wt (L5 — 87) sequence. Five sequences are repeated twice (L5 — 21 and L5 — 111; L5 — 43 and L5 — 112; L5 — 49 and L5 — 63; L5 — 64 and L5 — 93; L5 — 85 and L5 — 96). In total we had randomly expressed 55 proteins. Out of 55 expressed proteins 40 enzymatically active mutant variants (including control wt) of M-MuLV reverse transcriptase were successfully purified to 40-80% homogeneity according to SDS-PAGE. Total protein concentration in purified RT samples was in range of 0.6-5.5 mg/ml. Mutant RT variants were-tested for reverse transcriptase activity at 37° C., 50° C. and residual activity at 37° C. after 5 min incubation at 50° C. ( FIG. 8 ). Reverse transcriptase activity at 37° C. is normalized to be 100% and is omitted in FIG. 8 . Thus only two types of columns (percents of RT activity at 50° C. and residual RT activity at 37° C. after 5 min incubation at 50° C.) are shown. As a control wt M-MuLV reverse transcriptase used for mutants library construction is presented. This primary enzyme was expressed in the same vector and purified in the same way as mutant variants of RT. An average value of wt enzyme RT activity at 50° C. is about 45% comparing to activity at 37° C. Almost all tested proteins, with few exceptions, have higher than 45% activity at 50° C. An average value of RT activity at 50° C. for all tested mutants is about ˜92% and is more than 2 times higher comparing to wt enzyme (45%). Some mutants are 100% or even more active at 50° C. as they are at 37° C.: 20, 23, L5 — 16, L5 — 24, L5 — 30, L5 — 35, L5 — 37, L5 — 43, L5 — 46, L5 — 47, L5 — 49, L5 — 52, L5 — 55, L5 — 64, L5 — 65, L5 — 68, L5 — 72. The best mutants found have RT activity at 50° C. about 140% and more (3 times higher than 45% of wt): 20 (165%), L5 — 37 (162%), L5 — 43 (156%), L5 — 46 (135%), L5 — 47 (179%), L5 — 52 (137%), L5 — 64 (142%) and L5 — 68 (153%).
Even though majority of mutants have very high RT activities at 50° C., they are not as thermostable. Residual RT activity at 37° C. after 5 min incubation at 50° C. of wt control is −11%. The same average residual activity of selected enzymes is also similar ˜12%. Although some tested RT variants are substantially more thermostable and have residual activity 2-3 times higher than wt enzyme (11%): L5 — 8 (25%), L5 — 43 (32%), L5 — 46 (27%), L5 — 64 (28%), L5 — 65 (25%), L5 — 68 (31%).
Specific activity (u/mg of protein) for partially purified wt enzyme is −200,000 u/mg ( FIG. 9 ). Selected RT variants were expressed and purified in very diverse manner and an average specific activity (˜155,000 u/mg) is slightly lower as for wt control ( FIG. 9 ). In some cases specific activity is decreased, in some—increased (20—˜274,000 u/mg; L5 — 11—˜273,000 u/mg; L5 — 28—˜230,000 u/mg; L5 — 30—˜224,000 u/mg; L5 — 35—˜316,000 u/mg; L5 — 43—˜328,000 u/mg; L5 — 46—˜304,000 u/mg; L5 — 52—˜310,000 u/mg; L5 — 64—˜256,000 u/mg; L5 — 65—˜247,000 u/mg).
It is obvious that our selection system works well. Using increased temperature of RT reaction as a selection pressure factor, we have managed to evolve faster (specific RT activity at 50° C. is higher) and more thermostable (residual RT activity at 37° C. after 5 min preincubation at 50° C.) reverse transcriptases.
The source of valuable information is an alignment of selected protein sequences (Appendix 2). Sequences of analyzed proteins, whose activity at 50° C. was substantially better as compared to primary wt M-MuLV (70% and more comparing to 45% of wt activity) are highlighted in grey (Appendix 2). Number of mutagenized amino acids varied in range of 0 (wt or L5 — 87) to 12 (L5 — 9). List of mutations found in all selected RT variants is given in Appendix 3. Proteins are sorted by decreasing number of mutations. Most mutants (53 out of 104) had 4-6 mutations per sequence. It is obvious that reverse transcriptase sequence has some hot spots, which are very important and beneficial for the RT reaction in general and for the thermostability of enzyme. Those hot spots can be easily identified in multiple sequence alignment (Appendix 2) as conglomeration of mutations at particular position. Especially important are mutations found in better performing variants of M-MuLV reverse transcriptase (sequences are highlighted in grey—Appendix 2). Summarized information about the most frequent mutations (in decreasing order) is given in Appendix 4. As in previous appendix mutant proteins with substantially higher activity at 50° C. are highlighted in grey. If same mutation repeats for many times and tested reverse transcriptases with this mutation are better performing at 50° C., that means this mutation is somehow beneficial for reverse transcription reaction.
According to the frequency with which mutations are found they can be divided into five classes: 21-31 repeats; 14-18 repeats; 4-7 repeats; 2-3 repeats and 1 repeat. The first group of the most frequent mutations comprises four amino acids D524 (31 repeats); D200 (30 repeats); D653 (23 repeats) and D583 (21 repeats). Two amino acids (D524 and D583) are known to complex magnesium ions in active centre of ribonuclease H domain. Mutants D524G, D583N and E562Q are used to turn off RNase H activity of M-MuLV reverse transcriptase (Gerard et al., 2002), what improves synthesis of cDNA. Results of our selection are strikingly similar. Mutation of aspartate 524 is found in 31 sequences out of 98. Moreover, D524N substitution is found once, D524A—10 times and finally D524G—20 times. Thus our selection not only precisely targeted important amino acids, but also the same amino acid substitutions, which are known to be the best. Exactly the same situation is with mutation of aspartate 583, which is repeated in 21 selected proteins out of 104. Substitution D583E is found once, D583A—3 times, D583G—7 times and finally D583N—10 times. Again, same amino acid and same substitution (D583N), which is known to be the best is selected most frequently. Commercial enzyme SUPERSCRIPT II from Invitrogen has three mutations: D524G, D583N and E562Q (WO2004024749). An interesting thing is that mutation of the third amino acid substitution E562 in our selection is found only once (E562K in L5 — 71). This result suggests that most likely glutamate 562 is not as important as aspartates 524 and 583, or for some reasons exchange of this amino acid can cause some side effects and is not beneficial for RT reactions performed at increased temperatures (>50° C.).
Further analysis of selected proteins sequences allowed to identify many more hot amino acids positions, mutations of which are described in other patent applications for improved M-MuLV reverse transcriptase: H204R—7 repeats (U.S. Pat. No. 7,078,208); H638R—4 repeats (US20050232934A1); T197A—2 repeats (U.S. Pat. No. 7,056,716); M289V(L), T306A(M)—2 repeats (U.S. Pat. No. 7,078,208); E302K, N454K—2 repeats (WO07022045A2); E69G, L435P—1 sequence (WO07022045A2); Y64C, Q190R, V223M, F309S—1 sequence (U.S. Pat. No. 7,056,716); E562K—1 sequence (U.S. Pat. No. 7,078,208). There are also two selected sequences of reverse transcriptases which have combination of three amino acids substitutions described in literature (30—D200N, T306M, 0524N, D583G; L5 — 28—T306k F309S, D524A, H594R, F625S).
In addition to known mutations we have identified many more amino acids positions which are mutated quite often: D200N(A, G)—30 repeats; D653N(G, A, H, V)—23 repeats; L603W(M)—18 repeats; T330P—15 repeats; L139P—14 repeats; Q221R—6 repeats; T287A—6 repeats; 149V(T)—5 repeats; N479D—5 repeats; H594R(Q)—5 repeats; F625S(L)—5 repeats; P65S—4 repeats; H126S(R)—4 repeats; L333Q(P)—4 repeats; A502V—4 repeats; E607K(G, A)—4 repeats; K658R(Q)—4 repeats; H8P(R)-3 repeats; P130S—3 repeats; E233K—3 repeats; Q237R—3 repeats; N249D—3 repeats; A283D(T)—3 repeats; A307V—3 repeats; Y344H—3 repeats; P407S(L)—3 repeats; M428L—3 repeats; Q430R—3 repeats; D449G(A)—3 repeats; A644V(T)—3 repeats; N649S—3 repeats; L671P—3 repeats; E673G(K)—3 repeats; N678I—3 repeats (Appendix 4).
Best performing variants of RT usually have mutations of amino acids, which are modified most frequently:
20 (50° C.-123%)—D200N (30 repeats), L603W (18 repeats) and slightly modified C terminus—N678I, S679P, R680A;
L5 — 35 (50° C.-125%)—D200N (30 repeats), T330P (15 repeats), N479D (5 repeats);
L5 — 37 (50° C.-162%)—H123S (4 repeats), L149F (1 sequence), D200N (30 repeats), N454K (2 repeats), D583N (21 repeats);
L5 — 43 (50° C.-160%)—D200N (30 repeats), Q237R (3 repeats), T330P (15 repeats), D524G (31 repeats), F625S (5 repeats), D653N (23 repeats);
L5 — 46 (50° C.-135%)—D200N (30 repeats), T330P (15 repeats), D583N (21 repeats), T644T (3 repeats);
L5 — 47 (50° C.-179%)—N107S (1 repeat), H126R (4 repeats), T128A (1 repeat), 1179V (2 repeats), D200N (30 repeats), H642Y (2 repeats), D653N (23 repeats);
L5 — 52 (50° C.-137%)—D200N (30 repeats), T330P (15 repeats), Q374R (2 repeats), (D583N (21 repeats);
L5 — 64 (50° C.-142%)—D200N (30 repeats), D216G (2 repeats), D524G (31 repeats), E545G (2 repeats);
L5 — 65 (50° C.-127%)—D200N (30 repeats), Q238H (1 repeat), L570I (1 repeat), L603W (18 repeats);
L5 — 68 (50° C.-153%)—M39V (2 repeats), 149V (2 repeats), Q91R (2 repeats), H204R (7 repeats), T287A (6 repeats), N454K (2 repeats), F625L (5 repeats), D653H (23 repeats).
The combined data set of measured RT activities and sequence alignment analysis of mutant proteins allowed us to determine many beneficial mutations (and combinations thereof) in the sequence of M-MuLV reverse transcriptase sequence.
Example 3
Analysis of Moloney Murine Leukemia Virus Reverse Transcriptase Mutants
In vitro evolution experiment described in 2 nd example was very efficient. Gradually increased temperature of reverse transcription reaction was used as a selection pressure and generated a lot of different mutant variants of M-MuLV RT. Most of them were able to perform better at elevated temperatures comparing to primary enzyme. Sequence analysis of evolved reverse transcriptases indicates hot spots and most important amino acids positions (replacements), responsible for complex improvement of enzyme properties. In order to elucidate individual impact of different mutations single and multiple mutants of M-MuLV RT were constructed, partially purified and analyzed. Starting point for mutants construction was 7474 bp plasmid pET_his_MLV (SEQ ID No: 19) encoding M-MuLV RT with N-terminal. his-tag for fast protein purification using affinity chromatography. M-MuLV reverse transcriptase specific activity at 37° C., relative activity at 50° C. and relative residual activity at 37° C. after 5 min enzyme incubation at 50° C. were determined. In some cases RNase H activity was checked and cDNA synthesis reaction at different temperatures on 1 kb or 4.5 kb RNA was performed.
Methods and Materials
Initial plasmid pET_his_MLV (SEQ ID No: 19) was used as a starting material for mutagenic PCR. Mutations were introduced using mutagenic primers. Individual clones were sequenced and analyzed. M-MuLV RT mutants were expressed in T7 expression strain ER2566. Individual proteins and primary wt M-MuLV reverse transcriptase in the same construction were grown in 200 ml of LB to A590 ˜0.7 and purified via his-tag by affinity chromatography using 2 ml of Qiagen-Ni-NTA Superflow resin (all purification was performed under native conditions according to suppliers recommendations). Elution was performed in 1 ml of EB (50 mM—NaH 2 PO 4 , 300 mM—NaCl, 250 mM—imidazol, pH 8.0, 10 mM—β-mercaptoethanol and 0.1% of triton X-100). All proteins were dialyzed against 50 times excess of storage buffer (50 mM Tris-HCl (pH 8.3 at 25° C.), 0.1 M NaCl, 1 mM EDTA, 5 mM DTT, 0.1% (v/v) Triton X-100 and 50% (v/v) glycerol). Protein purity was checked on SDS-PAGE (usually ˜40-80% of target protein). Protein concentration was determined using Bradford reagent (Fermentas #R1271).
MLV reverse transcriptase activities were measured at 37° C., 50° C. (enzyme diluted in special dilution buffer: 30 mM Tris-HCl pH 8.3 at 25° C., 10 mM DTT, 0.5 mg/ml BSA) and rest of activity at 37° C. after 5 min enzyme incubation at 50° C. (enzyme diluted and its stability measured in 1×RT reaction buffer: 50 mM Tris-HCl pH 8.3 at 25° C., 4 mM MgCl 2 , 10 mM DTT, 50 mM KCl). Enzyme activity in all cases was assayed in the following final mixture: 50 mM Tris-HCl (pH 8.3 at 25° C.), 6 mM MgCl 2 , 10 mM DTT, 40 mM KCl, 0.5 mM dTTP, 0.4 MBq/ml [31-1]-dTTP, 0.4 mM polyA.oligo(dT) 12-18 . Activity units were determined measuring incorporation of dTMP into a polynucleotide fraction (adsorbed on DE-81) in 10 min at particular reaction temperature and comparing to known amounts of commercial enzyme. RNase H activity of M-MuLV reverse transcriptase variants was measured according to U.S. Pat. No. 5,405,776. RNase H activity of purified enzymes was assayed in reaction mixtures (50 μl) containing 50 mM Tris-HCl pH 8.3, 2 mM MnCl 2 , 1 mM DTT and [3H](A)n*(dT)n (5 μM [3H](A)n, 35 cpm/μmol; 20 μM (dT)n). Reactions were incubated at 37° C. for 10 min and were stopped by adding 10 μl of tRNA (1 mg/ml) and 20 μl of cold 50% TCA. After 10 minutes on ice, the mixture was centrifuged for 10 minutes in an Eppendorf centrifuge (at 25000 g). Forty μl of the supernatant was counted in a LSC-universal cocktail (Roth—Rotiszint eco plus). One unit of RNase H activity is the amount of enzyme required to solubilize one mole of [3H](A) n in [3H](A) n *(dT) n in 10 min at 37° C.
“RevertAid™ First Strand cDNA Synthesis Kit” (#K1622-Fermentas) and its control 1.1 kb RNA with a 3′-poly(A) tail in combination with oligo(dT) 18 primer was used to check purified reverse transcriptases for their ability to synthesize cDNA at different temperatures. Alternatively 4.5 kb RNA (synthesized from Eco31I linearized pTZ19R plasmid, which additionally contains piece of phage lambda DNA 5505-8469 bp) was used to test reverse transcription reaction. cDNA was synthesized 1 hr in 20 μl reaction volume using kit's components 1 μg of synthetic RNA, following provided protocol with only some minor modifications (without 5 min preincubation at 37° C.). Reverse transcription reactions were performed in 96 well PCR plate in Eppendorf Mastercycler gradient PCR machine applying corresponding temperature gradient. Synthesized cDNA was analyzed by alkaline agarose gel electrophoresis (staining with ethidium bromide). Samples of cDNA synthesis analysis on alkaline agarose gels are given in FIG. 16 .
Results
According to the frequency, with which mutations are found during the evolution of M-MuLV reverse transcriptase, they can be divided into five classes: 21-31 repeats; 14-18 repeats; 4-7 repeats; 2-3 repeats and 1 repeat. Construction of individual reverse transcriptase mutants in general was performed according to this information. Most frequently found mutations were tested first. Reverse transcriptase specific activity at 37° C., relative activity at 50° C. and relative residual activity at 37° C. after 5 min enzyme incubation at 50° C. were determined. In some cases RNase H activity was checked and cDNA synthesis reaction at different temperatures on 1 kb or 4.5 kb RNA was performed. All experimental data on individual mutants are presented in Appendix 5. Second column (“Selection frequency”) indicates the number of sequenced mutants, which had exact mutation and the number in the parentheses indicates total number of particular amino acid mutations found in selection. For example D200N—25 (30) means, that aspartate 200 replacement to asparagine was found 25 times out of 30 total D200 mutations. Reverse transcriptase specific activity measured at 37° C. is given in units per mg of protein. Relative enzyme activity at 50° C. and relative residual RT activity at 37° C. after 5 min incubation at 50° C. are given in percents normalized to specific activity (100%) of the same enzyme measured at 37° C. As a control (first line) is given wt M-MuLV reverse transcriptase used for mutants library construction. This primary enzyme is expressed in the same vector and purified in the same way as mutant variants of RT. Specific activity of wt enzyme is about 200,000 u/mg at 37° C., relative activity at 50° C. (comparing to activity at 37° C.)—45-50% (90,000-100,000 u/mg) and relative residual RT activity at 37° C. after 5 min incubation at 50° C. (comparing to activity at 37° C.) is about 11% (˜22,000 u/mg). Wild type enzyme has about 160-200 u/mol of RNase H activity and can synthesize full length 1 kb cDNA at 48° C. It is known, that M-MuLV reverse transcriptase is protected from thermal inactivation by the binding to template-primer substrate and contrary, enzyme is less thermostable in solution alone (Gerard et al., 2002). Relative residual RT activity at 37° C. after 5 min incubation at 50° C. directly indicates enzyme thermostability in solution without substrate. Meanwhile relative activity at 50° C. represents enzyme thermostability in complex with RNA/DNA substrate and speed of cDNA synthesis. Fast mutant variant of reverse transcriptase will give increased numbers of polymerase units at 50° C., even if it's thermostability will be the same as wild type enzyme. Highest temperature of cDNA synthesis (in our case 1 kb or 4.5 kb) is the most comprehensive parameter, which represents general ability of enzyme to synthesize cDNA at increased temperatures. Reverse transcriptase mutants, which have at least 10% increased: specific activity at 37° (220,000 u/mg, 200,000 u/mg-wt), relative activity at 50° C. comparing to mutant activity at 37° C. (≧54%, 45-50%-wt) or relative residual activity at 37° C. after 5 min incubation at 50° C. comparing to mutant activity at 37° C. (≧13%, 11%-wt), are shadowed in gray and considered as significantly improved enzymes. Mutants able to synthesize full length 1 kb cDNA at temperatures higher than 48° C. are also shadowed in gray.
Reverse transcriptase mutants with increased specific activity (≧220,000 u/mg) at 37° C. are (Appendix 5):
D200 (D200N—254,000 u/mg; D200G—276,000 u/mg; D200H—234,000 u/mg),
(T330N—223,000 u/mg; T330D—240,000 u/mg),
Q221 (Q221R—268,000 u/mg),
H594 (H594K—270,000 u/mg; H594Q—231,000 u/mg),
D449 (D449E—224,000 u/mg; D449N—221,000 u/mg),
M39 (M39N—349,000 u/mg),
M66 (M66L—237,000 u/mg; M66V—227,000 u/mg; M66I—240,000 u/mg),
H126 (H126R—227,000 u/mg),
W388 (W388R—266,000 u/mg),
I179 (I179V—251,000 u/mg).
Reverse transcriptase mutants with increased relative activity (54%) at 50° C. (comparing to activity at 37° C.) are (Appendix 5):
D200 (D200N—84%; D200A—87%; D200Q—103%; D200E—79%; D200V—131%; D200W—103%; D200G—88%; D200K—102%; D200R—68%; D200H—54%),
L603 (L603W—105%; L603F—104%; L603Y—95%; L603M—77%),
D653 (D653N—93%; D653K—106%; D653A—99%; D653V—98%; D653Q—93%; D653L—83%; D653H—116%; D653G—90%; D653W—93%; D653E—80%),
T330 (T330P—80%; T330N—69%; T330D—55%; T330V—65%; T330S—67%),
Q221 (Q221R—94%; Q221K—77%; Q221E—64%; Q221M—58%; Q221Y—77%),
E607 (E607K—84%; E607A—98%; E607G—72%; E607D—69%),
L139 (L139P—59%),
T287 (T287S—68%),
N479 (N479D—81%),
H594 (H594R—69%; H594K—80%; H594Q—75%; H594N—61%),
D449 (D449G—79%; D449E—77%; D449N—75%; D449A—99%; 0449V—83%),
M39 (M39V—54%; M39N—71%),
M66 (M66L—79%; M66V—73%; M66I—80%),
L333 (L333Q—54%),
H126 (H126R—58%),
P130 (P130S—70%),
Q91 (Q91R—56%),
W388 (W388R—72%),
R390 (R390 W—64%),
Q374 (Q374R—56%),
E5 (E5K—67%).
Reverse transcriptase mutants with increased relative residual activity (≧13%) at 37° C. after 5 min incubation at 50° C. (comparing to activity at 37° C.) are (Appendix 5):
D200 (D200N—15%; D200A—18%; D200Q—23%; D200R—27%; D200H—27%),
L603 (L603W—23%; L603Y—13%; L603P—15%),
D653 (D653N—21%; D653K—15%; D653A—18%; D653V—16%; D653Q—18%; D653H—13%; D653G—13%; D653W—13%; D653E—19%),
T330 (T330P—21%; T330N—13%; T330D—16%; T330S—15%),
T287 (T287A—13%; T287F—13%),
H594 (H594R—14%; H594Q—13%),
D449 (D449G—13%),
M39 (M39V—13%),
M66 (M66L—13%),
Y344 (Y344H—13%),
Q91 (Q91R—13%),
N649 (N649S—16%),
W388 (W388R—14%).
Mutants able to synthesize full length 1 kb cDNA at temperatures higher than 48° C. are (Appendix 5):
D200 (D200N—50.4° C.; D200H—50.4° C.),
L603 (L603W—53.1° C.; L603F—50.4° C.; L603Y—47.8-50.4° C.),
D653 (D653N—50.4-53.1° C.; D653K—50.4-53.1° C.; D653A—50.4° C.; D653V—50.4° C.; D653Q—50.4° C.; D653L—50.4° C.; D653H—50.4-53.1° C.; D653G—50.4° C.; D653W—50.4° C.),
Q221 (Q221R—50.4° C.),
E607 (E607K—47.8-50.4° C.),
H594 (H594K—47.8-50.4° C.; H594Q—47.8-50.4° C.).
Samples of 1 kb cDNA synthesis analysis on alkaline agarose gels are given in FIG. 16 A-D.
According to collected biochemical data most important positions in M-MuLV reverse transcriptase sequence, which can impact cDNA synthesis at increased temperatures, are: D200, L603, D653, T330, Q221, E607, L139, T287, N479, H594, D449, M39, M66, L333, H126, Y344, P130, Q91, N649, W388, R390, I179, Q374, E5.
In general mutations of interest can be combined in between and M-MuLV reverse transcriptase thermostability with and without substrate, velocity, processivity and overall ability to synthesize cDNA at increased temperatures can be further improved. Some data, which illustrates enzyme improvement by combinatorial approach are presented in Appendix 6. Single mutants D200N and L603W have relative activity at 50° C. 84% and 105%. Highest temperatures of 1 kb cDNA synthesis are 50.4° C. and 53.1° C. Double mutant D200N; L603W has relative activity 131% at 50° C. and can synthesize 1 kb cDNA at 56° C. Triple mutant D200N; L603W; T330P (80% at 50° C.; 1 kb cDNA at 47.8° C.) is improved further and has relative activity 175% at 50° C. and can synthesize 1 kb cDNA at 56-58° C. Quadruple mutant D200N; L603W; T330P; E607K (84% at 50° C.; 1 kb cDNA at 47.8-50.1° C.) has relative activity 174% at 50° C. and can synthesize 1 kb cDNA at 60-62° C. Quintuple mutant D200N; L603W; T330P; E607K; L139P (59% at 50° C.; 1 kb cDNA at 47.8° C.) has relative activity 176% at 50° C. and can synthesize 1 kb cDNA at 62° C. and that is about 14° C. higher temperature comparing to wild type M-MuLV reverse transcriptase (1 kb cDNA at 47.8° C.). Additive character of thermostability is also observed in case of:
N479D, H594R mutants (D200N; L603W—131% at 50° C., 1 kb cDNA at 56° C. versus D200N; L603W; N479D; H594R—182% at 50° C., 1 kb cDNA at 56-58° C., 4.5 kb cDNA at 56-58° C.),
T330P mutant (D200N; L603W; D653N; D524G—155% at 50° C., 1 kb cDNA at 58-60° C. versus D200N; L603W; D653N; D524G; T330P—180% at 50° C., 1 kb cDNA at 60-62° C.).
Samples of 4.5 kb cDNA synthesis analysis on alkaline agarose gels are given in FIG. 16 E-G.
Example 4
Modification of CRD—Selection for DNA Dependent DNA Polymerase Activity Using Biotin-dUTP (Proof of Principle)
This example illustrates activity-based selection strategy of reverse transcriptase as DNA dependent DNA polymerase, which is able to incorporate modified nucleotides into DNA-DNA substrate. The principle scheme of selection is schematically illustrated in FIG. 12 . Two plasmids pET_his_MLV_D583N_pD (encoding RNase H minus Moloney Murine Leukemia Virus (M-MLV) reverse transcriptase fused to protein D spacer) and its derivative pET_his_del_pD (encoding inactivated reverse transcriptase; 57 amino acids deletion in pol domain and mutation D583N in RNase H domain, Example 1, SEQ ID No: 2) were used as a starting material in this example. Initial DNA fragments encoding active and inactive reverse transcriptases were synthesized in two separate polymerase chain reactions using plasmids pET_his_MLV_D583N_pD and pET_his_del_pD as a target. Synthesized PCR fragments were used in transcription reaction for synthesis of mRNA, which lacks STOP codon at the 3′ end. Purified mRNAs were mixed to a ratio of 1:20=MLV (active RT):del (inactive RT). Double stranded DNA adapter (required for selection of DNA dependent DNA polymerase activity) was ligated to 3′ mRNA by T4 DNA ligase. This mRNA-dsDNA complex is used for in vitro translation reaction. The ribosome moving along the mRNA stops translation at the site of RNA-DNA hybridization (Tabuchi et al., 2001). Ribosome-mRNA/dsDNA-protein complexes were stabilized (as in conventional ribosome display) by dilution of translation mixture with ice-cold buffer containing 50 mM Mg 2+ . Mixture of ternary complexes (TC) was purified by ultracentrifugation on sucrose cushions. Purified ternary complexes (<3*10 9 molecules taken) containing mRNA-dsDNA linked to in vitro translated M-MuLV (RNase H—) reverse transcriptases were used to prepare reaction mixture additionally supplemented with biotin-dUTP and reaction buffer. Ice-cold reaction mixture was emulsified yielding ˜1*10 10 water in oil compartments ˜2 μm in size. Emulsified reaction mixture (less than one TC, ribosome-mRNA/dsDNA-protein per compartment) was incubated for 30 min at 37° C. After the temperature of compartmentalized reaction mixture is raised most of TCs dissociate releasing mRNA/dsDNA and reverse transcriptase. Successful incorporation reaction can occur only in compartments containing active M-MuLV (RNase H—) reverse transcriptase resulting in biotinylation of mRNA/dsDNA complex. Biotinylated complex can be selectively immobilized on streptavidin coated magnetic beads and specifically amplified by RT-PCR. As a result of successful experiment genes encoding active enzyme (in our case RT-PCR fragment of MLV_D583N_pD reverse transcriptase) should be enriched over genes encoding inactive enzyme (del_pD).
Methods and Materials
Production of mRNA/dsDNA Complex.
(1) Determination of Ligation Efficiency.
Efficiency of ligation reaction was determined by ligation of MLV_pD mRNA (synthesized from pET_his_MLV_pD plasmid, Example 1) with primer Long+Tb (SEQ ID No: 23) using ddC-Long2 primer (SEQ ID No: 22) as a splint. The 5′ end of Long+Tb was previously phosphorylated using T4 Polynucleotide Kinase (Fermentas).
Annealing mix of 36 μl was prepared by mixing of 8.5 μmol (˜10 μg) of purified MLV_pD mRNA with 4 times of molar excess of Long+Tb (SEQ ID No: 23) and 4.2 times of molar excess of ddC-Long2 (SEQ ID No: 22) in nuclease free water. The mixture was incubated at 70° C. for 5 min and then cooled to room temperature for 20 min. Before adding ligation reaction components mixture was moved to cooling stand for 2 min.
4.5 μl of 10× ligation buffer and 4.5 μl of T4 DNA ligase (5v/μl) (Fermentas) were added to 36 μl of annealing mixture. Ligation reaction was performed for 30 min at 37° C. and followed extraction once with equal volume of Roti® Phenol/chloroform (ROTH) and twice with equal volume of chloroform. Assuming that mRNA amount was close to initial amount taken for ligation reaction ˜5 μg of ligation products mix was diluted to 43 μl by nuclease free water. Aliquot of 2 μl of resultant mixture was left for analysis on agarose gel before immobilization on Dynabeads M-280 Streptavidin beads (Dynabeads® kilobase BINDER™ Kit (DYNAL Biotech)).
10 μl of resuspended Dynabeads was transferred to a 1.5 ml microcentrifuge tube, washed with 50 μl of Binding Solution provided in the kit. The tube was placed on the magnet for 1-2 min until beads settled at the tube and solution was removed. Dynabeads were gently resuspended by pipetting in 38 μl of Binding Solution supplemented with 2 μl of aqueous tRNA (tRNA from yeast (Roche)) solution (1 μg/μl) to minimize non-specific mRNA binding. 40 μl of Dynabeads in Binding solution was added to solution (˜40 μl) containing ligation products mix. The tube was incubated shaking at the +22° C. in termomixer (Eppendorf) for 60 min. After the binding of ligated mRNA/dsDNA, supernatant was removed and the beads were washed three times with 50 μl of Washing Solution (supplied in the kit). Collected Dynabeads with immobilizes ligated mRNA/dsDNA complex was resuspended in 26 μl of nuclease free water and followed extraction once with 40 μl of Roti® Phenol/chloroform (ROTH) and twice with 40 μl volume of chloroform to release mRNA/dsDNA complex from magnetic beads. 1; 2 and 5 μl of final mix were analysed on agarose gel along with sample (2 μl) left before immobilization and Mass Ruler™High Range DNA ladder. Amount of mRNA in mRNA/DNA complex purified on streptavidin beads was determined comparing mRNA amounts before and after the immobilization. The yield of recovered mRNA was ˜60%, what means that at least 60% of mRNA was successfully ligated with DNA duplex, resulting in mRNA/dsDNA complex.
(2) Determination of Biotin-dUTP Incorporation Efficiencies into mRNA/dsDNA Complex and into Self Primed mRNA.
As it was shown in first mRNA to dsDNA ligation experiment ligation reaction efficiency is ˜60% and more. Free mRNA left in ligation mixture can self prime and participate in extension reaction using M-MuLV reverse transcriptase and biotin-dUTP. This experiment was performed in order to demonstrate that mRNA/dsDNA complex (ligation product) is better substrate than free self primed mRNA.
MLV_D583N_pD mRNA was ligated with long+ oligonucleotide (SEQ ID No: 21) according procedure described above (construction of initial plasmids pET_his_MLV_D583N_pD and pET_his_delpD in details is described in Example 1). ˜12.5 ng of prepared (MLV_D583N_pD mRNA/long+) substrate was combined with ˜12.5 ng of del_pD mRNA previously incubated at 70° C. for 5 min, then cooled to room temperature for 20 min in nuclease free water, in total volume of 12.5 μl. The second mix for dTTP or biotin-dUTP incorporation by reverse transcriptase was prepared: 8 μl of 5× Reaction buffer for reverse transcriptase; 1 μl-40 u/μl RiboLock™ RNase inhibitor (Fermentas); 18.6 μl nuclease-free water; 0.4 μl-200 u/μl RevertAid™ Minus M-MuLV Reverse transcriptase (Fermentas). Prepared mix was divided to two tubes 2×15 μl and 1 μl of 1 mM dTTP (Femientas) or 1 μl of 1 mM biotin-dUTP (Fermentas) was added. Subsequentially 5 μl of substrate (from the first mix) was added to dTTP and biotin-dUTP containing mixtures. Reactions were carried out at 37° C. for 60 min. After that 1 μl of 0.5M EDTA (pH 8.0) was added to both samples and reaction mixtures were extracted once with equal volume of Roti® Phenol/chloroform (ROTH) and once with equal volume of chloroform followed by purification on G-50 MicroColumns (GE Healthcare). 2 μl of resultant reaction products were left for direct RT reaction (without streptavidin beads purification) and the remaining part of solutions were used for biotinylated mRNA-dsDNA complex immobilization on Dynabeads M-280 Streptavidin beads (Dynabeads® kilobase BINDER™ Kit (DYNAL Biotech)). 10 μl of resuspended Dynabeads was transferred to a 1.5 ml microcentrifuge tube, washed with 25 μl of provided Binding Solution. The tube was placed on the magnet for 1-2 min until beads settled at the bottom of the tube and solution was removed. Dynabeads were gently resuspended by pipetting in 90 μl of Binding Solution and 2 μl of aqueous tRNA (tRNA from yeast (Roche)) solution (1 μg/μl) was added to minimize non-specific mRNA binding. 40 μl of Dynabeads in Binding solution was added to solution (˜40 μl) containing the elongated by dTTP and biotin-dUTP RNA-DNA fragments. The tubes were incubated at the +22° C. in termomixer (Eppendorf) for 40 min by shaking (1400 rpm). After the binding step, supernatant was removed and the beads were washed three times with 50 μl of Washing Solution (provided in the kit) shaking (1400 rpm) for 5 min at +22° C. Collected Dynabeads with immobilizes elongated mRNA-dsDNA complex was resuspended in reverse transcription reaction mixture. Reverse transcription reaction mixture was prepared on ice: 20 μl-5× reaction buffer for Reverse Transcriptase (Fermentas); 10 μl-10 mM dNTP (Fermentas); 2.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 5 μl-20 μM pD — 42 oligonucleotide (SEQ ID No: 8); 2.5 μl RevertAid™ Minus M-MuLV Reverse transcriptase (200 u/μl) (Fermentas); 55 μl nuclease-free water. Prepared mix was divided to five 19 □l (5×19 □l) aliquots: two were used to resuspend Dynabeads with immobilized elongated mRNA/dsDNA complex or mRNA, the other two were transferred to the tubes with samples left without streptavidin beads purification and to the rest of 19 □l aliquot was added 1 □l of nuclease free water-egative reaction control to prove, that reaction mixture is not contaminated by DNA. All reaction mixtures were incubated by shaking (1000 rpm) at the +42° C. in termomixer (Eppendorf) for 1 hour until cDNA synthesis reaction was finished.
Amplification of cDNA was performed by nested PCR. Initial PCR mixture was prepared on ice: 14 μl-10× Taq buffer with KCl (Fermentas); 14 μl-2 mM of each dNTP (Fermentas); 8.4 μl-25 mM MgCl 2 (Fermentas); 2.8 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 0.7 μl-100 μM M_F primer (SEQ ID No: 11); 0.7 μl-100 μM M — 2R primer (SEQ ID No: 12); 92.4 μl water-mixture was divided into 7 samples for 19 μl (7×19 μl). To 5×19 μl of PCR master mix were added 1 μl of cDNA (1-5 RT samples); to the 6 th tube of PCR master mix 1 μl of water was added—negative PCR control; to the 7 th tube (positive PCR control)—1 μl of pET_his_MLV_D583N_pD plasmid (˜1 ng) was added. The cycling protocol was: initial denaturation step 3 min at 94° C., 25 cycles (45-sec at 94° C., 45 sec at 57° C., and 1 min at 72° C.) and final elongation 3 min at 72° C.
Predicted amplicons size 907 bp for MLV_D583N_pD and 736 bp for del_pD cDNA. PCR products were analyzed on 1% agarose gel loading 10 μl of PCR mix per well ( FIG. 13 ).
As it was expected efficient cDNA amplification is observed only in elongation reaction with biotin-dUTP. Very faint bands of amplified cDNA can be detected in elongation reaction with dTTP and can be explained by weak nonspecific binding of mRNA to streptavidin beads. After purification on streptavidin beads DNA encoding MLV_D583N_pD gene (907 bp) is enriched over DNA of del_pD (736 bp). That means mRNA/dsDNA complex is elongated by biotin-dUTP much more efficiently than self primed del_pD mRNA.
(3) Preparation of mRNA Mixture (MLV_D583N_pD:del_pD=1:20) and RNA/dsDNA Complex.
Preparation of PCR fragments for in vitro transcription. PCR mixture was prepared on ice: 20 μl-10× Taq buffer with KCl (Fermentas); 20 μl-2 mM of each dNTP (Fermentas); 12 μl-25 mM MgCl 2 (Fermentas); 16 μl—DMSO (D8418—Sigma); 4 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1 μl-100 μM pro-pIVEX primer (SEQ ID No: 3); 1 μl-100 μM pD-ter—primer (SEQ ID No: 20); 122 μl water-mixture divided into two tubes 2×98 μl. To 2×98 μl of PCR master mix were added either 2 μl of pET_his_MLV_D583N_pD (diluted to ˜1 ng/μl) or 2 μl of pET_his_del_pD (diluted to ˜1 ng/μl) (construction of initial plasmids pET_his_MLV_D583N_pD and pET_his_del_pD in details is described in Example 1). The cycling protocol was: initial denaturation step 3 min at 94° C., 30 cycles (45 sec at 94° C., 45 sec at 53° C., and 2 min at 72° C.) and final elongation 5 min at 72° C. Amplification efficiency was ˜7000 fold from 2 ng of plasmid (7873 bp) target to ˜5 μg (50 ng/μl) of amplified product (2702 bp PCR fragment MLV_D583N_pD from pET_his_MLV_D583N_pD; 2531 bp PCR fragment del_pD from pET_his_del_pD).
Transcription mixture was prepared: 80 □l-5×T7 transcription buffer (1 M HEPES-KOH pH 7.6; 150 mM Mg acetate; 10 mM spermidin; 0.2 M DTT); 56 □l-112 mM of each NTP (Fermentas); 16 □l-20 u/□l T7 RNA polymerase (Fermentas); 8 □l-40 u/□l RiboLock RNase inhibitor (Fermentas); 114 □l nuclease-free water-mixture divided into two tubes 2×165 □l and add 35 □l-20 ng/□l of PCR fragment MLV_D583N_pD (unpurified PCR mixture) or 35 □l-20 ng/□l of PCR fragment del_pD PCR (unpurified PCR mixture). Transcription was performed 2 hr at 37° C.
Both transcription mixtures were diluted to 200 μl with ice-cold nuclease-free water and 200 μl of 6 M LiCl solution were added. Mixtures incubated 25 min at +4° C. and centrifuged for 25 min at +4° C. in cooling centrifuge at max speed (25,000 g). Supernatant was discarded and RNA pellet washed with 500 μl of ice-cold 75% ethanol. Tubes were centrifuged again for 5 min at +4° C. at max speed and supernatant was discarded. RNA pellet was dried for 5 min at room temperature and subsequently resuspended in 400 μl of nuclease-free ice-cold water by shaking for 15 min at +4° C. and 1400 rpm. Tubes were centrifuged again for 5 min at +4° C. at max speed to separate not dissolved RNA. About 380 μl of supernatant were transferred to new tube with 42 μl of 10× DNase I buffer (Mg 2+ ) (Fermentas); 3 μl-1 u/μl DNasel (RNase-free) (Fermentas) and incubated for 20 min at +37° C. to degrade DNA. Reaction mixtures were extracted once with equal volume of Roti® Phenol/chloroform (ROTH) and twice with equal volume of chloroform to remove DNasel. 43 μl of 3 M Sodium acetate pH 5.0 solution and 1075 μl of ice-cold 96% ethanol were added to each tube. Finally RNA was precipitated by incubation for 30 min at −20° C. and centrifugation for 25 min at +4° C. at max speed (25,000 g). Supernatant was discarded and RNA pellet washed with 500 μl of ice-cold 75% ethanol. Tubes were centrifuged again for 4 min at +4° C. at max speed and supernatant was discarded. RNA pellet was dried for 5 min at room temperature and subsequently resuspended in 150 μl of nuclease-free ice-cold water by shaking (1400 rpm) for 15 min at +4° C. RNA solution was aliquot for 10 μl and liquid nitrogen frozen. Concentration of mRNA was measured spectrophotometrically and double-checked on agarose gel along with RiboRuler™ RNA Ladder, High Range (Fermentas).
mRNA/dsDNA complex was produced by ligation of long+ oligodeoxynucleotide to mRNA using ddC-Long2 oligodeoxynucleotide as a splint. The 5′ end of long+ was previously phosphorylated using T4 Polynucleotide Kinase (Fermentas). Oligodeoxynucleotide ddC-Long2 has 3′ end modification (ddC) in order to prevent possibility of 3′ end extension by reverse transcriptase on its natural RNA-DNA substrate. Annealing mix of 50 μl was prepared by mixing of 17 μmol of purified mRNA mixture at ratio of 1:20=MLV_D583N_pD (active RT): del_pD (inactive RT) with 4.3 time of molar excess of long+ and 4.1 time of molar excess of ddC-Long2 in nuclease free water. The mixture was incubated at 70° C. for 5 min and then cooled to room temperature for 20 min. Before adding ligation reaction components mixture was moved to cooling stand for 2 min.
5 μl of 10× ligation buffer and 5 μl of T4 DNA ligase (5 v/μl) (Fermentas) were added to 40 μl of annealing mixture. Negative ligation reaction was carried out using the same annealing mixture in 1× ligation buffer without T4 DNA ligase. Prepared ligation reaction mixtures were incubated at 37° C. for 30 min. To stop ligation 1 μl of 0.5M EDTA (pH 8.0) was added to both tubes and reaction mixtures were extracted once with equal volume of Roti® Phenol/chloroform (ROTH) and twice with equal volume of chloroform followed by concentration of reaction products at 30° C. for 10 min in vacuum Concentrator 5301 (Eppendorf). Desalting was performed using illiustra ProbeQuant G-50 MicroColumns (GE Healthcare). Concentrations of ligation products were determined on agarose gel along with RiboRuler™ RNA Ladder, High Range (Fermentas)—mRNA mixture (MLV_D583N_pD:del_pD=1:20) ligated to long+/ddC-Long2 oligodeoxynucleotides ˜0.24 μg/μl (sample with T4 DNA ligase) and simple mRNA mixture with long+/ddC-Long2 oligodeoxynucleotides ˜0.06 μg/μ1 (sample without T4 DNA ligase).
(4) General Control of mRNA/dsDNA Complex by Incorporation of [α-P 33 ]dATP.
Prepared mRNA/dsDNA complex (substrate) was tested for dTTP (or biotin-dUTP) and subsequent [α-P 33 ]dATP incorporation by reverse transcriptase. Reaction mixture: 16 μl of 5× Reaction buffer for reverse transcriptase; 4 μl-40 u/μl RiboLock™ RNase inhibitor (Fermentas); 2 μl [α-P 33 ]dATP (10 mCi)/ml, SRF-203 (Hartmann Analytic)); 35 μl nuclease free water; 1 μl-200 u/μl RevertAid™ Minus M-MuLV Reverse transcriptase (Fermentas). Prepared mix was divided to two tubes 2×28 μl and 2 μl of 1 mM dTTP (Fermentas) or 2 μl of 1 mM biotin-dUTP (Fermentas) was added. Resultant mixtures were divided to two tubes 2×15 μl. To first tube 1.25 μl (˜0.3 μg) of ligation products plus 3.75 μl of nuclease free water were added. To second tube 5 (˜0.3 μg) of negative ligation reaction products were added. Reaction mixtures were incubated at 37° C. for 30 min. After that, 1 μl of 0.5M EDTA (pH 8.0) was added to all tubes and reaction mixtures were extracted once with equal volume of Roti® Phenol/chloroform (ROTH) and twice with equal volume of chloroform followed by purification on illiustra ProbeQuant G-50 MicroColumns (GE Healthcare). Reactions products were analyzed on agarose gel along with RiboRuler™. RNA Ladder, High Range (Fermentas) FIG. 14A . In all samples (with and without ligase) we can see discreet band (˜2500b) of del_pD mRNA (20 times smaller amount of MLV_D583N_pD mRNA ˜2700b, which was present in mRNA mixture can not be distinguished). Subsequently agarose gel was dried on filter paper and radiolabeled mRNA/dsDNA complex (at the same position as mRNA) was detected only in case of positive ligation samples (with ligase) and not in case of negative ligation samples (without ligase) FIG. 14B .
(5) Selection for DNA Dependent DNA Polymerase Activity Using Biotin-dUTP.
Previously prepared mRNA/dsDNA complex (mRNA mix MLV_D583N_pD (active RT):del_pD (inactive RT)=1:20) was used for in vitro translation employing synthetic WakoPURE system (295-59503—Wako). Translation mixture for WakoPURE system (25 μA: 12.5 μl—A solution (Wako); 5 μl—B solution (Wako); 0.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 0.25 μl-1 M DTT; 1.75 μl nuclease-free water and 5 μl-0.24 μg/μl mRNA/dsDNA substrate (˜1200 ng). In vitro translation was performed for 120 min at 37° C.
Translations (˜25 μl) was stopped by adding 155 μl of ice-cold stop buffer WBK 500 +DTT+triton (50 mM Tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)-Triton X-100 (T8787—Sigma)) and centrifuged for 5 min at +4° C. and 25,000 g. Very carefully 160 μl of centrifuged translation mixture was transferred on the top of 840 μl 35% (w/v) sucrose solution in WBK 500 +DTT+Triton X-100 (50 mM Tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—Triton X-100 (T8787—Sigma); 35% (w/v)—sucrose (84097—Fluka)) to transparent 1 ml ultracentrifugation tubes (343778—Beckman). Ternary complexes (TC) consisted of mRNA/dsDNA-ribosome-protein(tRNA) were purified by ultracentrifugation at TL-100 Beckman ultracentrifuge in TLA100.2 fixed angle rotor (Beckman) at 100,000 rpm for 9 min at +4° C. Initially 750 μl of solution was removed from the very top of the centrifugation tube. Then (very carefully to keep small transparent pellet of TC at the bottom of ultracentrifugation tube intact) tube walls were washed with 750 μl of WBK 500 (50 mM tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl). Finally all solution was removed starting from the very top of the centrifugation tube and pellet was dissolved in 30 μl of ice-cold stop buffer WBK 500 +DTT+triton (50 mM Tris-acetate pH 7.5 at 25° C.; 50 mM NaCl; 50 mM Mg-acetate; 500 mM KCl; 10 mM DTT; 0.1% (v/v)—Triton X-100 (T8787—Sigma)).
As it was determined using radioactively labeled mRNA after ultracentrifugation 5%-30% of input mRNA is located in ternary complex pellet. Therefore it was predicted to have less than 360 ng (30% from 1200 ng mRNA used in translation reaction) of mRNA in 30 μl of buffer (˜12 ng/μl or 9*10 9 molecules/μl of ternary complex).
Modified nucleotide incorporation reaction mix was prepared on ice by mixing: 5 μl-5× reaction buffer for Reverse Transcriptase (Fermentas); 1.25 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 2.5 μl-1 mM biotin-dUTP (Fermentas); 40.95 μl nuclease-free water and 0.3 μl of purified (<2.7*10 9 molecules) TC. According to the protocol 50 μl of nucleotide incorporation reaction mix contains <2.7*10 9 molecules of ternary complex.
Oil-surfactant mixture was prepared by mixing ABIL EM 90 (Goldschmidt) into mineral oil (M5904—Sigma) to final concentration of 4% (v/v) (Ghadessy and Holliger, 2004; US2005064460). Emulsions were prepared at +4° C. in 5 ml cryogenic vials (430492—Corning) by mixing 950 μl of oil-surfactant mixture with 50 μl of RT mixture. Mixing was performed using MS-3000 magnetic stirrer with speed control (Biosan) at ˜2100 rpm; Rotilabo®—(3×8 mm) magnetic bar with centre ring (1489.2—Roth); water phase was added in 10 μl aliquots every 30 sec, continuing mixing for 2 more minutes (total mixing time—4 min). According to optical microscopy data compartments in prepared emulsions vary from 0.5 μm to 10 μm in size with average diameter of ˜2 μm. Therefore it was expected to have ˜1*10 10 water in oil compartments after the emulsification of 50 μl reverse transcription reaction mixture, which contains less than 2.7*10 9 molecules of ternary complex (about one mRNA-dsDNA complex and reverse transcriptase molecules per 3-4 compartments).
Prepared emulsion was incubated 30 min at +37° C.
To recover the reaction mixture from emulsion 20 μl of 0.1M EDTA was added to emulsion, stirred for 10 sec, then 50 μl phenol/chloroform mix was added and stirred for additional 10 sec. After that, emulsion was transferred to 1.5 ml microcentrifuge tube, 0.5 ml of water-saturated ether was added mixed by vortexing and centrifuged for 10 min at room temperature for 16,000 g. Oil-ether phase was removed leaving concentrated (but still intact) emulsion at the bottom of the tube. Finally emulsions were broken by extraction with 0.9 ml water-saturated ether; 0.9 ml water-saturated ethyl-acetate (in order to remove ABIL EM 90 detergent) and twice 0.9 ml water-saturated ether. Water phase was dried for 12 min under vacuum at room temperature followed removal of incorporated nucleotides on illiustra ProbeQuant G-50 MicroColumns (GE Healthcare). 2 μl aliquot of resultant mixture was left for direct RT reaction (without streptavidin beads purification) and the remaining part of solution was used for biotinylated mRNA/dsDNA complex immobilization on Dynabeads M-280 Streptavidin beads (DYNAL Biotech).
Dynabeads® kilobase BINDER™ Kit (DYNAL Biotech) was used for isolation of biotinylated mRNA-dsDNA complex according provided product description. 5 μl of resuspended Dynabeads was transferred to a 1.5 ml microcentrifuge tube, washed with 20 μl of provided Binding Solution. The tube was placed on the magnet for 1-2 min until beads settled at the tube and solution was removed. Dynabeads were gently resuspended by pipetting in 50 μl of Binding Solution and 1 μl of aqueous tRNA (tRNA from yeast (Roche)) solution (1 μg/μl) was added to minimize non-specific mRNA binding. 50 μl of Dynabeads in Binding solution were added to solution (˜50 μl) containing the biotinylated RNA-DNA fragments. The tube was incubated shaking at the +22° C. in termomixer (Eppendorf) for 1 hour. After the binding of mRNA/dsDNA, supernatant was removed from the beads, and the beads were washed two times with 50 μl of Washing Solution (provided in the kit) shaking (1400 rpm) for 5 min at +22° C. and once with 50 μl of Washing Solution shaking (1400 rpm) for 12 min at +22° C. Collected Dynabeads with immobilized biotinylated mRNA/dsDNA complex were resuspended in reverse transcription reaction mixture.
Reverse transcription reaction mixture for selected mRNA/dsDNA complex was prepared on ice: 12 μl-5× reaction buffer for Reverse Transcriptase (Fermentas); 6 μl-10 mM dNTP (Fermentas); 1.5 μl-40 u/□l RiboLock RNase inhibitor (Fermentas); 0.3 μl-20 μM pD — 42 oligonucleotide (SEQ ID No: 8); 1.5 μl RevertAid™ Minus M-MuLV Reverse transcriptase (200 u/μl) (Fermentas); 35.7 μl nuclease-free water. Prepared mix was divided to three 19 □l aliquots: one was used to resuspend Dynabeads with immobilized biotinylated mRNA/dsDNA complex, the other aliquot of 19 μl was transferred to the tube with sample of elongated mRNA/dsDNA complex left without streptavidin beads purification and to the rest of 19 □l aliquot was added 1 □l of nuclease free water (negative reaction control—to prove that reaction mixture is not contaminated). All reaction mixtures were incubated by shaking (1000 rpm) at the +42° C. in termomixer (Eppendorf) for 1 hour.
Amplification of cDNA was performed by nested PCR. Initial PCR mixture was prepared on ice: 10 μl-10× Taq buffer with KCl (Fermentas); 10 μl-2 mM of each dNTP (Fermentas); 6 μl-25 mM MgCl 2 (Fermentas); 2 μl-1 u/μl LC (recombinant) Taq DNA Polymerase (Fermentas); 1-2.5 u/μl Pfu DNA Polymerase (Fermentas); 0.5 μl-100 μM RD_Nde primer (SEQ ID No: 9); 0.5 μl-100 μM pD — 55 primer (SEQ ID No: 10); 65 μl water-mixture was divided into 5 samples for 19 μl (5×19 μl). To 3×19 μl of PCR master mix were added 1 μl of cDNA (1-3 RT samples); to one tube with 19 μl of PCR master mix 1 μl water was added—negative PCR control. For positive PCR control 1 μl of pET_his_MLV_pD plasmid (˜1 ng) was added. The cycling protocol was: initial denaturation step 3 min at 94° C., 30 cycles (45 sec at 94° C., 45 sec at 58° C., and 3 min at 72° C.) and final elongation 5 min at 72° C.
Nested PCR mixture for partial gene amplification (for better resolution of MLV_D583N_pD:del_pD cDNA ratio in RT samples) was prepared on ice: 20 μl-10× Taq buffer with KCl (Fermentas); 20 μl-2 mM of each dNTP (Fermentas); 12 μl-25 mM MgCl 2 (Fermentas); 0.9 μl-5 u/μl Taq DNA Polymerase (Fermentas); 1.0 μl-100 μM M_F primer (SEQ ID No: 11); 1.0 μl-100 μM M — 2R primer (SEQ ID No: 12); 135.1 μA water-mixture was divided 5×38 μl. 2 μl of first PCR (primers set RD_Nde//pD — 55) product were added to prepared nested PCR mixture. Master mix was mixed again and divided into two tubes (2×20 μl) for 30 or 35 PCR cycles amplification. The cycling protocol was: initial denaturation step 3 min at 94° C., 30 or 35 cycles (45 sec at 94° C., 45 sec at 57° C., and 1 min at 72° C.) and final elongation 3 min at 72° C. Expected length of PCR fragments was 907 bp for MLV_D583N_pD and 736 bp for del_pD. Amplification was analyzed on 1% agarose gel loading 10 μl of PCR mix per well ( FIG. 15 ).
Results
1. Double stranded (dsDNA) adaptor was successfully ligated to mRNA using T4 DNA ligase. Ligation efficiency is about 60% as it was determined by ligation of dsDNA-biotin adapter. mRNA/dsDNA complex can be specifically purified on streptavidin beads, providing an opportunity to discriminate between biotin labelled and unlabelled substrates. Free mRNA is much worse substrate for DNA dependent DNA polymerase comparing to mRNA/dsDNA. As a consequence 60% ligation efficiency of dsDNA to mRNA is good enough and such a substrate can be successfully used in evolution scheme.
2. General selection experiment using mRNA/dsDNA complex (mRNA mixture MLV_D583N_pD:del_pD=1:20) was performed. In vitro translation was performed using WakoPURE protein translation system and compartmentalized biotin-dUTP incorporation reaction in to dsDNA was carried out to demonstrate the enrichment of genes encoding active (MLV_D583N_pD) reverse transcriptase over genes encoding inactivated enzyme (del_pD). According to selection scheme ( FIG. 12 ) incorporation reaction of biotin-dUTP should occur only in aqueous compartments containing active (MLV_D583N_pD) reverse transcriptase resulting in biotinylation of mRNA/dsDNA complex. DNA dependent DNA polymerase is selected by binding of the biotinylated complex to streptavidin immobilized on magnetic beads, and then the selected gene-is amplified by RT-PCR. Genes encoding active enzyme (in our case RT-PCR fragment for MLV_D583N_pD reverse transcriptase) were enriched over genes encoding inactive enzyme ( FIG. 15 ). Initial ratio of genes MLV_D583N_pD:del_pD was 1:20 and final ratio (after enrichment) was −1:1. Respectively an enrichment factor in this particular experiment was −20 folds. Enrichment factors calculated from different experiments varied in range from 5 to 200. And it was confirmed that DNA dependent DNA polymerase could be selected for modified nucleotide incorporation applying Compartmentalized Ribosome Display (CRD) method. Selection of conventional DNA dependent DNA polymerases can be performed straight away. Biotin-dUTP can be exchanged to different nucleotide analogues of interest including nucleotide analogues having 3′ modifications. After the incorporation of such nucleotide analogues into DNA strand 3′ end is blocked, can't be extended and elongation reaction will be terminated. This approach is used in sequencing by synthesis (SBS) scheme and DNA polymerase suitable for SBS can be easily evolved using compartmentalized ribosome display (CRD) technique.
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Applicants incorporate by reference the material contained in the accompanying computer readable Sequence Listing identified as SEQ_TXT.txt, having a file creation date of Feb. 29, 2012 2:09 P.M. and file size of 651 kilobytes. | The present invention provides a process for the production of nucleic acid encoding a target protein, which comprises: (a) providing an array of RNA or DNA molecules including one or more encoding the target protein; (b) generating a target protein from the array to form RNA-protein or DNA-protein complexes in which the RNA or DNA molecule is non-covalently or covalently bound to the complex; (c) separating the complexes into compartments wherein most or all of the compartments contain no more than one complex; (d) subjecting the complexes to reaction conditions which allow target protein activity; and (e) selecting nucleic acid encoding the target protein on the basis of the activity associated therewith, wherein when the complex is a DNA-protein complex in which the DNA is non-covalently bound, step b) is performed in the absence of separate compartments for each complex. | 0 |
BACKGROUND AND SUMMARY OF THE INVENTION
This invention is directed to an improved endoscope for removing scar tissue that is constricting hollow organs of the body. It was an object of the invention to provide a means for removing tissue under visual control with high precision and in a manner that is as unstressful to the patient as possible.
The endoscopes that have been used up to now to remove tissue under visual control have involved electrical surgery, a surgical knife, or a punching device. The devices have not been entirely successful in that electrical surgery will leave a more extensive zone of dead tissue due to heat development; a surgical knife is very difficult to use due to the very small operation site and because of the limited minipulability of the cutting element, and punching or nipping devices in the form of small forceps cause uncontrolled tearing of the tissue, which leads to irregular wound areas.
The present invention allows tissue resection by means of a grinding or milling process under endoscopic observation. The grinding or milling head connected to a rotating shaft is advanced toward the tissue to be removed under visual control, and the tissue is then slowly resected under constant observation, preferably by means of the cutting surfaces of small diamonds provided on the grinding head. The present method allows millimeter-precise operation without leaving an extended zone of dead tissue, as the grinding process takes place without any significant temperature. The device further provides the continuous flushing required for good endoscopic vision which also assures continuous cooling during the grinding operation. The resulting wound areas are smooth and can be exactly adapted to the normal shape of the organ.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is shown in the drawings in which:
FIG. 1 is a longitudinal section through the end part of the endoscope with drive unit;
FIG. 2 is a horizontal section through the drive unit;
FIG. 3 is a longitudinal section through the tip of the endoscope.
FIG. 4 is a longitudinal section of a further embodiment of the invention.
DETAILED DESCRIPTION
The outer tube 3 of the endoscope 1 is preferably made of metal such as stainless steel or an alloy corresponding to the state of the art. As can best be seen in FIG. 3, tube 3 accommodates a tube 4 for the lens system and cold light guide and rotating shaft 5 with its bearing 6. The inlet connection 9 for flushing solutions allows the flushing solution to flow between the lens tube and the bearing of the rotating shaft through the endoscopic tube to the tip 2 of the endoscope and to flush the operation site clear.
The tubing 4 containing the lens system and the cold light guide as well as the bearing for the rotating shaft 6 is stabilized by one or more brackets 8 located within tube 3. The rotating shaft 5 carries the grinding head 7 which is provided with a screw connection for replacement purposes. A conventional locking ring 10 seals off the endoscopic tube and is connected with a sealing element 11 which is firmly fixed to the tube 4 containing the lens system with cold light guide, and which has one end of spring 17 fixed to its lower part. This spring 17 which is fastened at its other end to the drive unit, pushes the drive unit 23 away from the endoscopic tube. The drive unit can be displaced on the tube 4 containing the lens system and cold light guide as well as on a special guide rail 20 between the endoscopic tube with its locking element 11 and a limit stop plate firmly connected to the tube 4 for lens system and cold light guide against the pressure of the spring 17. These movements are controlled by the surgeon's hand holding the instrument by placing a finger into the ring 16 and gripping the handle.
When the bearing of the rotating shaft enters into the drive unit 23, the bearing will be fixed in its position by means of a conventional locking device 18 which may, for example, be in the form of a clamp attached to driving unit 23 and engaging tube 6. The conical wheel of the rotating shaft 21 meets the conical wheel of the flexible shaft 22 within chamber 34 contained within the drive unit 23. The flexible shaft 24 is fixed to the drive unit by means of a standard locking device 25. The standard locking device 13 fastens the lens system with cold light guide within its respective tube 4. Cold light is introduced through inlet 14, and the eyepiece of the lens system 15 forms the rear end of the endoscope.
Another embodiment of the invention is shown in FIG. 4. In this embodiment, the conical wheel 22 of the electric motor 31 which is supplied with electric current via a feeder cable 35. The drive unit 23 slides on tube 4 containing optical lens and cold light guide. The drive unit 23 is moved on guide rods 26 against the resistance of the spring 27. These movements are controlled by the surgeon placing his fingers into the rings 29 and 32.
List of Elements
1. Endoscope for tissue resection
2. Endoscope tip
3. Hollow outer tube of endoscope
4. Tube for lens system and cold light guide
5. Rotating shaft
6. Bearing of rotating shaft
7. Removable grinding head
8. Bracket for tube containing lens systems and cold light guide, and for rotating shaft bearing
9. Inlet connection for flushing solution
10. Locking ring for endoscopic tube
11. Locking plate firmly connected with tube containing lens system and cold light guide
12. Rear limit stop plate for movable drive unit, firmly connected with tube containing lens system and cold light guide
13. Locking system for tube containing lens system and cold light guide
14. Cold light connection
15. Eyepiece
16. Ring for surgeon's fingers
17. Spring
18. Locking system for rotating shaft bearing
19. Handle for surgeon's fingers
20. Guide rail for drive unit
21. Conical wheel of rotating shaft
22. Conical wheel of flexible shaft
23. Drive unit
24. Connection piece of flexible shaft
25. Locking system for flexible shaft on drive unit
26. Guide rods for drive unit
27. Spring for guide rods
28. Cold light cable
29. Ring for surgeon's fingers
30. Flushing duct
31. Electric motor
32. Ring for surgeon's thumb
33. Front lens of optical system
34. Chamber accommodating conical wheels
35. Electric current supply cable | An endoscope for resecting tissue inside body cavities, the principal feature of which is that the endoscopic tube contains a shaft carrying a grinding or milling head, which allows precise removal of scar tissue or other fairly firm tissue under endoscopic control without leaving irregular or thermally damaged wound sites. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to transaction tool promulgation.
2. Background Art
Transaction tools are instruments issued by a third party (i.e., transaction tool issuer) to facilitate transactions between a holder (i.e., transaction tool holder) and a recipient by “vouching” for a holder's identity and/or trustworthiness. Accordingly, transaction tools are used to authenticate the identity and/or trustworthiness of a holder.
Transaction tools may be managed for issuers and holders by management systems. As an example, for an issuer of credit cards, a management system may facilitate day-to-day transactions by verifying credit availability. Additionally, for an issuer of digital certificates, a management system may facilitate day-to-day transactions by authenticating the validity of a digital certificate. Furthermore, from a holder standpoint, a corporation may use a management system to manage digital certificates installed by employees on computers in the corporation's network. While transaction tool management systems generally facilitate day-to-day use of transaction tools, such systems do not manage the promulgation of a new and/or updated transaction tool. Accordingly, the holder of the transaction tool (i.e., the person and/or entity to which the transaction tool is initially issued) must manually notify recipients of the new and/or updated transaction tool if the holder desires to engage in future transactions with the recipient.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 —A block diagram of a system for promulgating a transaction tool to a recipient in accordance with one non-limiting aspect of the present invention;
FIG. 2 —A block diagram of a system for promulgating a transaction tool to a recipient in accordance with another non-limiting aspect of the present invention;
FIG. 3 —A block diagram of a system for promulgating a transaction tool to a recipient in accordance with yet another non-limiting aspect of the present invention;
FIG. 4 —A flow diagram of a method of promulgating a transaction tool to a recipient in accordance with one non-limiting aspect of the present invention; and
FIG. 5 —A flow diagram of a method of promulgating a transaction tool to a recipient in accordance with another non-limiting aspect of the present invention.
DETAILED DESCRIPTION
In view of the foregoing, one or more embodiments of the present invention may provide one or more of the following advantages: decrease the amount of human intervention required to acquire and/or update (i.e., renew, revoke, etc.) a transaction tool, increase transaction efficiency, and/or reduce transaction failures resulting from missing and/or outdated transaction tools.
Referring to FIG. 1 , a block diagram of a system 100 for promulgating a transaction tool to a recipient in accordance with one non-limiting aspect of the present invention is shown. The system 100 , generally comprises a transaction tool issuer 102 , a transaction tool holder 104 , and a recipient device 106 . The transaction tool issuer (i.e., issuer) 102 is generally electronically coupled to the transaction tool holder (i.e., holder) 104 such that electronic signals (e.g., communication signals) may be bi-directionally transferred between the issuer 102 and the holder 104 . Similarly, the transaction tool holder 104 is generally electronically coupled to at least one recipient (i.e., recipient device) 106 such that electronic signals may be bi-directionally transferred between the holder 104 and each recipient 106 .
In at least one embodiment of the present invention, the transaction tool issuer 102 is a computer or other electronic device which executes software application programs and/or which performs other logical exercises. However, the transaction tool issuer 102 may include any type of unit or entity which can generate and/or modify a transaction tool.
The transaction tool issuer 102 generally receives a Transaction Tool Operation Request signal (e.g., a request for a new transaction tool, a request to update an existing transaction tool, and the like) from the transaction tool holder 104 , generates (i.e., issues) a Transaction Tool Update signal comprising a new and/or updated transaction tool in response to the Transaction Tool Operation Request signal, and presents the Transaction Tool Update signal (i.e, the new and/or updated transaction tool) to the transaction tool holder 104 .
In one exemplary embodiment, the transaction tool issuer 102 is associated with an issuer of digital certificates and the Transaction Tool Update signal may comprise a new and/or updated public key. In another exemplary embodiment, the transaction tool issuer 102 is associated with an issuer of digital certificates and the Transaction Tool Update signal may comprise a new and/or updated private key. In yet another exemplary embodiment, the transaction tool issuer 102 is associated with a financial institution and the Transaction Tool Update signal may comprise new and/or updated credit card information (e.g., credit card number, expiration date, and the like). In still yet another exemplary embodiment, the transaction tool issuer 102 is associated with a financial institution and the Transaction Tool Update signal may comprise new and/or updated debit card information (e.g., debit card number, expiration date, and the like). However, the transaction tool issuer 102 may be associated with any business, organization, individual, and/or other entity which performs the function of issuing and/or maintaining a transaction tool. Similarly, the Transaction Tool Update signal may comprise any appropriate transaction tool information (i.e., data) to meet the design criteria of a particular application.
The transaction tool holder 104 is generally a computer or other electronic device which executes software application programs and/or which performs other logical exercises.
In at least one embodiment of the present invention, the transaction tool holder 104 is electronically coupled to an update engine 110 . For example, in one non-limiting embodiment the update engine 110 is physically integrated into the transaction tool holder 104 . In another non-limiting embodiment, the update engine 110 is physically remote to the transaction tool holder 104 . In general, the update engine 110 may be physically located in any appropriate location to meet the design criteria of a particular application.
The update engine 110 generally manages the acquisition and maintenance (i.e., updating, renewal, etc.), of a transaction tool associated with the transaction tool holder 104 . The update engine may be implemented as any suitable logical device to meet the design criterial of a particular application, such as software (e.g., an application program executable by the transaction tool holder 104 ), firmware, hardware (e.g., an Application Specific Integrated Circuit), or a combination thereof.
In one exemplary embodiment, the update engine 110 determines that a transaction tool associated with the transaction tool holder 104 is set to expire within a predetermined period of time (i.e., a predetermined expiration date of the transaction tool falls within a predetermined period of time). In response to the pending expiration of the associated transaction tool, the update engine 110 may generate a request for an updated transaction tool (i.e., Transaction Tool Operation Request signal), present the request to the transaction tool issuer 102 , and receive a Transaction Tool Update signal from the transaction tool issuer 102 in response to the Transaction Tool Update signal.
In another exemplary embodiment, the update engine 110 determines that a new transaction tool is required for the transaction tool holder 104 . The update engine 110 may determine that a new transaction tool is required in response to any appropriate trigger to meet the design criteria of a particular application, such as a user request, a signal from a transaction tool management system, and the like. Accordingly, the update engine 110 may generate a request for a new transaction tool (i.e., Transaction Tool Update signal), present the request to the transaction tool issuer 102 , and receive a Transaction Tool Update signal from the transaction tool issuer 102 in response to the Transaction Tool Update signal.
The update engine 110 may also determine (i.e., identify, select, etc.) one or more recipient devices 106 (i.e., recipients), such as a computer in electronic communication with the transaction tool holder 104 , to receive the new and/or updated Transaction Tool. In one exemplary embodiment, the recipients 106 are selected based at least in part on a contact list 114 (e.g., an electronic mail address book) electronically coupled to the update engine 110 . In another exemplary embodiment, the update engine 110 is electronically coupled to a transaction log 112 and the update engine 110 selects the recipients 106 based at least in part on the transaction log 112 . In the exemplary embodiment having the transaction log 112 , the transaction log 112 may comprise device identification information for at least one device that has received a transaction tool related to the transaction tool holder 104 . As will be appreciated by one of ordinary skill in the art, the present invention transcends any particular criteria used to determine the recipients 106 and the embodiments discussed are exemplary and non-limiting.
The update engine 110 , via the transaction tool holder 104 , generally presents (i.e., publishes, transmits) the new and/or updated transaction tool (i.e., credential, credentials) to one or more recipients 106 identified by the update engine 110 . The update engine 110 may publish the new and/or updated credential to the recipients 106 using any appropriate communication link to meet the design criteria of a particular application, such as the Internet (e.g., using electronic mail and/or file transfer), satellite communication channels, dedicated communication wires, and the like.
In at least one embodiment of the present invention, the update engine 110 may publish the new and/or updated credential to a recipient 106 using a handshaking routine performed during a transaction between the recipient 106 and the update engine 110 and/or the transaction tool holder 104 . The new and/or updated credential may be signed for providing confirmation that the new and/or updated credential is authentic.
Referring to FIG. 2 , a block diagram of a system 200 for promulgating a transaction tool to a recipient in accordance with another non-limiting aspect of the present invention. The system 200 may be implemented similarly to the system 100 with the exception that the recipient 106 is a software application program (i.e., application program). In the non-limiting embodiment shown in FIG. 2 , the application program resides on the transaction tool holder 104 . However, the application program may be resident on any appropriate device in electronic communication (i.e., electronically coupled) with the update engine 110 to meet the design criteria of a particular application.
In at least one non-limiting embodiment of the present invention, the transaction tool is a public key certificate and/or a private key for encrypting data, the application program is an electronic mail application, and the application program archives the transaction tool update such that data (e.g., electronic messages) encrypted using the transaction tool update may be deciphered beyond a predefined expiration date of the transaction tool update.
Referring to FIG. 3 , a block diagram of a system 300 for promulgating a transaction tool to a recipient in accordance with another non-limiting aspect of the present invention is shown. The system 300 may be implemented similarly to the system 100 with the exception that the transaction tool issuer 102 ′ comprises an update engine 110 ′ and the transaction tool issuer 102 ′ is generally electronically coupled to the recipient devices 106 such that electronic signals may be bi-directionally transferred between the transaction tool issuer 102 ′ and each recipient 106 .
More particularly, in the non-limiting embodiment shown in FIG. 3 , the update engine 110 ′ of the transaction tool issuer 102 ′ generally determines (i.e., identifies, selects, etc.) one or more recipient devices 106 (i.e., recipients), such as a computer and/or application program in electronic communication with the transaction tool issuer 102 ′, to receive a Transaction Tool Update signal (i.e., a new and/or updated Transaction Tool).
In one exemplary embodiment, the recipients 106 are selected based at least in part on a contact list 114 ′ (e.g., an electronic mail address book) electronically coupled to the update engine 110 ′. In another exemplary embodiment, the update engine 110 ′ is electronically coupled to a transaction log 112 ′ and the update engine 110 ′ selects the recipients 106 based at least in part on the transaction log 112 ′. In the exemplary embodiment having the transaction log 112 ′, the transaction log 112 ′ may comprise device identification information for at least one device that has received a transaction tool related to the transaction tool holder 104 ′. As will be appreciated by one of ordinary skill in the art, the present invention transcends any particular criteria used to determine the recipients 106 and the embodiments discussed are exemplary and non-limiting.
The update engine 110 ′, via the transaction tool issuer 102 ′, generally presents (i.e., publishes, transmits) the Transaction Tool Update signal (i.e., credential, credentials) to one or more recipients 106 identified by the update engine 110 ′ and/or the transaction tool holder 104 ′. The update engine 110 ′ generally publishes the new and/or updated credential using any appropriate communication link to meet the design criteria of a particular application, such as the Internet (e.g., using electronic mail and/or file transfer), satellite communication channels, dedicated communication wires, and the like.
In at least one embodiment of the present invention, the update engine 110 ′ may publish the new and/or updated credential to a recipient 106 using a handshaking routine performed during a transaction between the recipient 106 and the update engine 110 ′ and/or the transaction tool issuer 102 ′. The new and/or updated credential may be signed for providing confirmation that the new and/or updated credential is authentic.
Referring to FIG. 4 , a flow diagram 400 of a method of promulgating a transaction tool to a recipient in accordance with one non-limiting aspect of the present invention is shown. The method 400 may be advantageously implemented in connection with the system 100 , described previously in connection with FIG. 1 , the system 200 , described previously in connection with FIG. 2 , and/or any appropriate system to meet the design criteria of a particular application. The method 400 generally comprises a plurality of blocks or steps (e.g., steps 402 , 404 , 406 , 408 , and 410 ) that may be performed serially. As will be appreciated by one of ordinary skill in the art, the steps of the method 400 may be performed in at least one non-serial (or non-sequential) order, and one or more steps may be omitted to meet the design criteria of a particular application.
As illustrated in step 402 , a Transaction Tool Operation Request signal may be generated by an update engine (e.g., update engine 110 ). In at least one embodiment of the present invention, the Transaction Tool Operation Request signal is generated in response to a determination that a transaction tool associated with a transaction tool holder (e.g., transaction tool holder 104 ) requires renewal and/or updating. In at least one other embodiment of the present invention, the Transaction Tool Operation Request signal may be generated in response to a user and/or transaction tool management system requesting a new transaction tool. However, the Transaction Tool Operation Request signal may be generated in response to any appropriate trigger to meet the design criteria of a particular application.
At step 404 , the update engine generally transmits the Transaction Tool Operation Request signal to a transaction tool issuer (e.g., the transaction tool issuer 102 ). The update engine may transmit the Transaction Tool Operation Request signal using any appropriate communication link to meet the design criteria of a particular application, such as the Internet (e.g., using electronic mail and/or file transfer), satellite communication channels, dedicated communication wires, and the like.
At step 406 , the update engine generally receives a Transaction Tool Update signal from the transaction tool issuer. The Transaction Tool Update signal generally comprises a new and/or updated transaction tool generated by the transaction tool issuer in response to the Transaction Tool Operation Request signal.
At step 408 , the update engine may determine one or more recipient devices (e.g., recipient 106 ). As previously discussed in connection with systems 100 and 200 , the recipient may be any electronic device and/or application program in electronic communication (i.e., electronically coupled) with the update engine. The update engine may determine a recipient using any appropriate criteria to meet the design requirements of a particular application.
At step 410 , the update engine generally transmits the Transaction Tool Update signal comprising the new and/or updated transaction tool to the recipient devices. The update engine may transmit the Transaction Tool Update signal to the recipient devices using any appropriate communication link to meet the design criteria of a particular application, such as the Internet (e.g., using electronic mail and/or file transfer), satellite communication channels, dedicated communication wires, and the like.
Referring to FIG. 5 , a flow diagram 500 of a method of promulgating a transaction tool to a recipient in accordance with another non-limiting aspect of the present invention is shown. The method 500 may be advantageously implemented in connection with the system 300 , described previously in connection with FIG. 3 , and/or any appropriate system to meet the design criteria of a particular application. The method 500 generally comprises a plurality of blocks or steps (e.g., steps 502 , 504 , 506 , and 508 ) that may be performed serially. As will be appreciated by one of ordinary skill in the art, the steps of the method 500 may be performed in at least one non-serial (or non-sequential) order, and one or more steps may be omitted to meet the design criteria of a particular application.
As illustrated in step 502 , an update engine (e.g., update engine 110 ′) may receive a Transaction Tool Operation Request signal from a transaction tool holder (e.g., transaction tool holder 104 ′). The Transaction Tool Operation Request signal generally comprises a request for a new and/or updated transaction tool.
At step 504 , the update engine may generate a Transaction Tool Update signal comprising a new and/or updated transaction tool in response to the Transaction Tool Operation Request signal.
At step 506 , the update engine generally determines one or more recipient devices (e.g., recipient 106 ). As previously discussed, the recipient may be any electronic device and/or application program in electronic communication (i.e., electronically coupled) with the update engine. The update engine may determine a recipient using any appropriate criteria to meet the design requirements of a particular application.
At step 508 , the update engine generally transmits the Transaction Tool Update signal comprising the new and/or updated transaction tool to the recipient devices and/or the transaction tool holder. The update engine may transmit the Transaction Tool Update signal to the recipient devices and/or the transaction tool holder using any appropriate communication link to meet the design criteria of a particular application, such as the Internet (e.g., using electronic mail and/or file transfer), satellite communication channels, dedicated communication wires, and the like.
In accordance with various embodiments of the present invention, the methods described herein are intended for operation as software programs running on a computer processor. Dedicated hardware implementations including, but not limited to, Application Specific Integrated Circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. Furthermore, alternative software implementations including, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.
It should also be noted that the software implementations of the present invention as described herein are optionally stored on a tangible storage medium, such as: a magnetic medium such as a disk or tape; a magneto-optical or optical medium such as a disk; or a solid state medium such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories. A digital file attachment to email or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the invention is considered to include a tangible storage medium or distribution medium, as listed herein and including art-recognized equivalents and successor media, in which the software implementations herein are stored.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. | A method for using an update engine to promulgate a transaction tool to a recipient. The method may include the steps of: generating a transaction tool operation request signal wherein the transaction tool operation request signal includes a request for a new transaction tool and/or an updated transaction tool, transmitting the transaction tool operation request signal to a transaction tool issuer, receiving a transaction tool update signal from the transaction tool issuer wherein the transaction tool update signal includes a new transaction tool and/or an updated transaction tool, determining the recipient, and transmitting the transaction tool update signal to the recipient. | 6 |
FIELD OF THE INVENTION
This invention relates to biopsy instruments and methods of taking biopsies and more specifically to instruments and methods for acquiring repeated subcutaneous biopsies and for removing lesions without having to reinsert the instrument into the patient, organ, and tissue mass to be biopsied for each sample acquired.
BACKGROUND OF THE INVENTION
It is often desirable and frequently necessary to sample or test a portion of tissue from humans and other animals, particularly in the diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions and other diseases or disorders. Typically, in the case of cancer, when the physician establishes by means of procedures such as palpation, x-ray or ultra sound imaging that suspicious circumstances exist, a biopsy is performed to determine whether the cells are cancerous. Biopsy may be done by an open or percutaneous technique. Open biopsy removes the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). Percutaneous biopsy on the other hand is usually done with a needle-like instrument and may be either a fine needle aspiration (FNA) or a core biopsy. In FNA biopsy, individual cells or clusters of cells are obtained for cytologic examination and may be prepared such as in a Papanicolaou smear. In core biopsy, as the term suggests, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen section or paraffin section.
The type of biopsy utilized depends in large part on circumstances present with respect to the patient and no single procedure is ideal for all cases. However, core biopsy is extremely useful in a number of conditions and is being used more frequently by the medical profession.
To arrive at a definitive tissue diagnosis, intact tissue is needed from an organ or lesion within the body. In most instances, only part of the organ or lesion need be sampled. However, the portions of tissue obtained must be representative of the organ or lesion as a whole. In the past, to obtain tissue from organs or lesions within the body, surgery had to be performed to locate, identify and remove the tissue. With the advent of medical imaging equipment (x-rays and fluoroscopy, computed tomography, ultrasound, nuclear medicine, and magnetic resonance imaging) it became possible to identify small abnormalities even deep within the body. However, definitive tissue characterization still requires obtaining adequate tissue samples to characterize the histology of the organ or lesion.
For example, mammography can identify non-palpable (not perceptible by touch) breast abnormalities earlier than they can be diagnosed by physical examination. Most non-palpable breast abnormalities are benign; some of them are malignant. When breast cancer is diagnosed before it becomes palpable, breast cancer mortality can be reduced. However, it is often difficult to determine if pre-palpable breast abnormalities are malignant, as some benign lesions have mammographic features which mimic malignant lesions and some malignant lesions have mammographic features which mimic benign lesions. Thus, mammography has its limitations. To reach a definitive diagnosis, tissue from within the breast must be removed and examined under a microscope. Prior to the late 1980's, reaching a definitive tissue diagnosis for non-palpable breast disease required a mammographically guided localization, either with a wire device, visible dye, or carbon particles, followed by an open, surgical biopsy utilizing one of these guidance methods to lead the surgeon to the non-palpable lesion within the breast.
The open method is illustrated in FIGS. 1A through 1E. FIG. 1A depicts an accurately localized lesion. A lesion 5 is located per one of the aforementioned visualization means. The breast 1 is pierced with a localization wire 3 with the intention of positioning the large diameter section of the wire through the center of the lesion to act as a temporary marker. In a subsequent procedure, tissue is removed around the area marked by the localization wire. The tissue is then prepared and sectioned for evaluation. Open surgical breast biopsies have many drawbacks. They can be disfiguring, expensive (in terms of direct costs to the patient and indirect costs to society from the patient being away from work), and are imperfect (the error rate for surgical biopsy has been reported to be from 2% to 22%). FIG. 1B illustrates a localization wire 3 incorrectly placed by a radiologist. FIG. 1C illustrates a properly placed localization wire 3 but poor tissue selection 7 by the surgeon in which the lesion 5 was not harvested. FIGS. 1D and 1E illustrate a properly harvested lesion 9 with the wrong section prepared for analysis. As shown, the lesion 5 is included in the harvested tissue sample 9. However, in sectioning the tissue sample 9 along A--A and B--B for examination, the lesion 5 was missed. Any of these errors will lead to an incorrect diagnosis of the lesion. Open surgical biopsies also carry a small mortality risk (the risk of anesthesia) and a moderate morbidity rate (including bleeding, infection, and fracture or migration of the localizing wire). In cases where multiple lesions are present in the breast, a surgeon is reluctant to biopsy each lesion due to the large tissue mass that must be extracted with each lesion. The most convenient lesion is taken which results in an incomplete diagnosis. Finally, surgical breast biopsies are extremely common. In the United States, alone, it is estimated that open, surgical breast biopsies are performed on over 500,000 women annually. A less invasive alternative has long been sought.
In the fall of 1988, two different stereotactic guidance systems were modified to allow the guiding portion of each system to accommodate spring powered devices such as the Biopty® (Bard Radiology) gun. In the summer of 1989, free-hand ultrasound guidance techniques were developed to guide the Biopty® gun to breast lesions seen by ultrasound. With the introduction of stereotactic and ultrasound guided percutaneous breast biopsies, an alternative to open, surgical breast biopsy was at hand.
With image guided percutaneous core breast biopsy, it may be possible to greatly reduce the number of open, surgical breast biopsies performed. However, there are limiting factors with image guided breast biopsies. The current generation of biopsy guns acquire specimens slowly. The placement of the needle of the gun has to be made very accurately because only one small core is obtained per insertion at any one location. To sample a lesion thoroughly, many separate insertions must be made. Finally, there is no means to completely excise a small lesion at the time of the initial diagnostic biopsy.
Stereotactic and ultrasound guidance systems have improved continuously since their introduction. Guidance systems are now more accurate, user friendly, and rapid than when they were introduced. On the other hand, automated biopsy gun systems have not evolved much since their initial introduction.
Many biopsy procedures now require a plurality of samples to be taken. For example, up to six or more samples of tissue are often required when testing the tissues of the breast, prostate gland and other body organs. In order to take multiple tissue samples using the prior art biopsy devices, each time a sample is taken, the device must be removed, and a new puncturing of the breast or organ made. This action is tedious and time consuming. Moreover, multiple manual penetrations of the organ are typically somewhat painful, and such penetrations are subject to bleeding and infection.
Multiple samples may be obtained with a device disclosed in U.S. Pat. No. 4,976,269 (Mehl). The Mehl device allows the cannula to remain in the body, but the stylette with its tissue receiving notch must be manually withdrawn from the tissue, organ, and cannula so that the test sample can be removed, a tedious and time consuming process. Samples may be compromised through prolonged sliding contact with the inside surface of the cannula during withdrawal of the styler. To obtain a second tissue sample, the stylet is manually reinserted into the biopsy device, through the cannula, and into the organ and tissue to be sampled.
Another significant drawback of the prior art is that the stylets bearing the tissue samples must be manually handled. This exposes those persons handling the stylets to danger of infection, e.g., HIV infection. Additionally, with present devices, the stylers and samples are handled on an individual basis. The tissue samples are often damaged or destroyed due to improper handling. There is also the possibility of loss or mislabeling of the samples.
A need thus exists for a biopsy device which can take a plurality of tissue samples painlessly, in rapid sequence, minimizing handling in a way that protects the handling personnel and the tissue samples.
The True Cut® needle (Travenol Laboratories) optimally allows a roughly cylindrical shaped sample of tissue, termed a "core," to be obtained from a pointed, side cutting device, percutaneously. The True Cut® needle as shown in FIG. 1F, comprises a pointed inner stylette 11 with a side facing notch 13 to receive tissue near its pointed end (tissue receiving notch) and an outer, sharpened sliding cannula 15. The operational sequence of the True Cut® needle biopsy system is shown schematically in FIG. 1G. Once the lesion is targeted, the inner stylette 11 is thrust into the organ or lesion of interest. Tissue passively prolapses into the side facing notch 13 and the outer cannula 15 is rapidly advanced, thereby cutting off the sample of tissue contained within the notch. The entire needle system is withdrawn out of the body and the sample is manually extracted from the receiving notch 13 and handled for processing. Each specimen requires reassembly of the needle system, relocation of the lesion, and repositioning of the device.
The True Cut® needle works within a certain set a operating parameters, but is rough on organs and lesions, often only obtaining small fragments of tissue, and is quite operator dependent--some individuals are good at operating the device and some are not. FIG. 1H shows tissue 17 optimally prolapsed into the receiving chamber 13. FIG. 1I and 1J illustrate other common occurrences when using the True Cut® needle system. In FIG. 1I, tissue 17 is partially prolapsed into the receiving notch 13. Partial prolapse results in insufficient sampling, and may be caused by insufficient dwell time before cutting, by a natural bias of the tissue to migrate away from the receiving notch when it is pierced, or by forced migration of the tissue during forward movement of the cutter 15. FIG. 1J illustrates bleeding at a preceding biopsy site that has formed into a clot 19. Tissue 17 is not allowed into the tissue receiving notch 13 which is occupied by clot 19. In this situation a clot sample is obtained instead of lesion or normal tissue.
A variety of biopsy needles and guns have been described and used for obtaining tissue specimens. These guns are an improvement over manual use of the True Cut® needle. One such biopsy gun currently used is described in U.S. Pat. No. Re. 34,056, entitled "TISSUE SAMPLING DEVICE", issued to Lindgren et al. Additional examples of biopsy gun devices are disclosed in U.S. Pat. Nos. 4,600,014 and 4,958,625. The Lindgren Automatic Core Biopsy Device (ACBD) is an instrument which propels a needle set with considerable force and speed in order to pierce the tumor mass and collect the tissue sample. The ACBD has allowed physicians to accurately test tissue masses in the early stages of growth and has contributed to the medical trend of early diagnosis and successful treatment of cancer. The ACBD allows a biopsy to be performed on tumor masses as small as two millimeters in diameter. This procedure is performed under ultrasound or X-ray guidance. Tumors of this size cannot be biopsied reliably by hand since the tumor is about the same size as the biopsy needle. Manual attempts at biopsy pushes the tumor away without piercing the mass. Automatic puncture devices accelerate the needle at such a velocity that even a small tumor can be pierced. Typically, Automatic Core Biopsy Devices use the True Cut® needle set design. The stylet is advanced into the tissue under spring power followed by the cannula which cuts and traps the tissue sample in the notch of the stylet as previously discussed. The True Cut® needle yields a core sample which is semi-circular in cross-section with a length determined by the stroke of the ACBD. The most common True Cut® needle size used by ACBD's is 14 gauge. The use of 14 gauge needles is a compromise between the physician's desire to use the smallest, least invasive, needle gage and the pathologist's needs for as large a tissue sample as possible to minimize false-positive and false-negative diagnosis. This compromise in needle size leads the physician to obtain multiple core samples from the biopsy site to allow the pathologist sufficient tissue for an accurate diagnosis.
The Automatic Core Biopsy Devices are able to obtain tissue from within the body with less trauma, more consistently, and in larger quantities than the manually operated True Cut® needle. However, they do have disadvantages. For example, they are typically spring powered devices and must be manually cocked with a plunger bar. Such "cocking" of the gun requires considerable force and the gun must be cocked for each biopsy cut. When actuated, the springs provided in the gun accelerate the needles until a mechanical stop position is reached creating a loud snapping noise and jerking motion which is a problem both to the physician and the patient.
Further short comings of the ACBD's include: 1) Absence of a mechanism for capturing tissue in the tissue receiving notch under varying types of tissue consistency (from soft to hard) prior to the action of the outer cutting cannula. 2) No means is provided for systematic change in position of the tissue receptacle about the long axis of the needle system. If the ACBD is held in the same orientation or is mounted in a holder, the cutting action is always in the same place, i.e., the True Cut® type needle only cuts from a 7:00 o'clock position to a 5:00 o'clock position each time it is operated. 3) They do not provide a means for systematic change in the position of the tissue receiving notch along the long axis of the stylette. 4) They do not provide for a means to allow the removal of a volume of tissue about the long axis of the needle that is larger than the diameter of the True Cut® type needle. 5) They do not provide for a means to remove a volume of tissue along the long axis of the needle that is larger in volume than the tissue receptacle of the True Cut® type needle. 6) They do not provide for a means to remove more than one core of tissue per entry into the body, organ, and lesion. With existing technology, each entry retrieves only one core sample. To obtain another core, another entry into the lesion is required. Consequently, the process of obtaining sufficient tissue to characterize heterogeneous tissue is very time consuming and tedious. With the passage of time, patient fatigue leads to patient motion and accuracy can fall. 7) They do not provide for a means to code or decode where, within the organ or lesion, the core samples originated to allow later reconstruction of the histology of the entire volume sampled. 8) They do not provide a means which allows complete removal of small lesions. Various attempts to overcome one or more of the disadvantages of the ACBD have been made.
U.S. Pat. No. 5,183,052, entitled "AUTOMATIC BIOPSY INSTRUMENT WITH CUTTING CANNULA", issued to Terwilliger describes a biopsy instrument having a styler and a cannula wherein the instrument urges the cannula past the stylet in order to collect a tissue sample and simultaneously causes a vacuum to be communicated to the cannula in order to assist the collection of the tissue sample by the cannula.
U.S. Pat. No. 5,183,054, entitled "ACTUATED BIOPSY CUTTING NEEDLE WITH REMOVABLE STYLET", issued to Burkholder et al., discloses a biopsy device having a tubular cannula through which a stylet having a stylet cavity near the distal end is placed. The styler is removable from the cannula and removed from the biopsy device through the housing so that the tissue sample obtained by the biopsy device may be manually retrieved while the cannula remains in place within the patient, near the area being sampled. Thereafter, the styler may be reinserted through the housing and cannula into the patient's tissue where additional tissue samples may be obtained. In this way, trauma to the tissue that ordinarily occurs upon reinsertion of the cannula and stylet is minimized.
U.S. Pat. No. 5,234,000, entitled "AUTOMATIC BIOPSY DEVICE HOUSING A PLURALITY OF STYLETS", issued to Hakky et al. describes a biopsy device for taking a plurality of samples of tissue from a living being. The device comprises a housing having a portion arranged to be held by a person using the device, a cannula having a proximal portion and a distal portion and being coupled to the housing. A plurality of stylets are located in the housing, with each of the stylets having a proximal end, a distal end, and a tissue receiving notch located adjacent the distal end. Each stylet is individually propelled through the cannula into the body so that a portion of the tissue prolapses into the notch. The Burkholder et al. and Hakky et al. devices share all of the disadvantages of True Cut® type devices described previously with the exception of being limited to acquiring a single sample. In addition, transportation of samples by withdrawing stylettes from the instrument may compromise quality of the specimens through prolonged contact with the inside surface of the cannula.
U.S. Pat. No. 5,195,533, entitled "BIOPSY NEEDLE INSTRUMENT FOR STORING MULTIPLE SPECIMENS", issued to Chin et al. describes a biopsy needle instrument which includes a housing, an axially elongated stylet extending from the housing and a cannula coaxially extending from the housing and disposed about the stylet means. The stylet and cannula can move relative to each other and to the housing between extended and retracted positions. The styler and cannula define, during a given operation, a specimen of a predetermined specimen axial length. The stylet includes means coacting with the cannula for storing multiple, sequentially obtained specimens within the instrument. While multiple samples may be acquired with this device, there is no provision for separating the samples from each other or maintaining the integrity of the individual samples. In addition, the volume of tissue collected per entry into the body cannot exceed the capacity of the receiving notch.
U.S. Pat. No. 4,651,753, entitled "ENDOSCOPIC MULTIPLE BIOPSY INSTRUMENT", issued to Lifton describes a biopsy instrument for use with an endoscope which includes a rigid cylindrical end attached to the distal end of a flexible arrangement of tubes. The rigid end comprises a cylindrical body having a cavity therein. The cavity extends towards the distal end of the body and is of size sufficient to hold plural samples therein. Inside the cylindrical body is a passageway which serves as a conduit for aspiration of tissue into the cavity and cylindrical body and a knife for cutting the tissue. Furthermore, a plunger is arranged coaxially with the knife for pushing individual biopsy samples of a plurality into the distal end cavity of the cylindrical body. This device is clearly for endoscopic use and would be inappropriate for use in obtaining samples from a breast or organ interior. Although this device employs an active means to urge tissue into the receiving notch, it bears the same deficiencies as the Chin device. The volume of tissue collected per bodily insertion cannot exceed the collection chamber volume, the origin of the samples cannot be differentiated, and the samples recovered must be manually handled for preparation.
The requirements of the physician and the pathologist dictate the need for an alternative approach in the function and design of the conventional ACBD, needle sets and other biopsy devices. The ideal product would allow for collection of larger tissue volume through a small opening, reliable active tissue capture mechanism, more accurate control of the location from which samples are acquired, ability to acquire multiple samples from the biopsy site without having to reinsert the biopsy needle, less traumatic transportation and storage of samples with minimum handling, and correlation of sample storage to harvest site.
SUMMARY OF THE INVENTION
Based on the prior art instruments for biopsy sampling of tissue masses and the actual present state of this art, there exists a need for an instrument which is capable of obtaining multiple samples at the biopsy site without having to insert the sampling device into the patient and organ multiple times. Additionally, there is a need to record the location from which each sample was acquired.
The present invention has means to capture tissue prior to cutting the tissue, means to direct and position the cutting chamber in arbitrary positions about and along the long axes of the invention, means for rapid and atraumatic removal of an arbitrary number of core samples with only one insertion into the body and organ, and means for coding and decoding the location from which the samples were obtained. Together, these means allow for more complete sampling of large lesions and for the complete removal of small lesions.
That portion of the present invention that is within the body can: A) pierce the lesion that is to be biopsied; B) orient and record the location of the tissue receptacle within the biopsy invention and within the body, to provide controlled sampling along and about the long axis of the invention; C) urge tissue into the tissue receptacle of the invention and retain the captured tissue therein; D) cut the captured tissue, creating a core, from the surrounding tissue; E) transport the core out of the body while maintaining the position of the biopsy invention within the body and organ; and F) repeat steps "B" through "E" any number of times (to obtain complete sampling or complete lesion removal) or can be withdrawn from the body when steps "B" through "E" have been completed.
It is the general purpose of the current invention to use medical image guidance (mammography, ultrasound, computed tomography, or magnetic resonance imaging) to position the device at or adjacent to an abnormality within the breast to allow sampling or removal of the abnormality in such a manner that the integrity of the removed tissue is preserved for histologic analysis and in such a manner that the location of the removed tissue can be determined by the sequence in which the tissue was removed. The current device is an improvement over the prior art which performs percutaneous biopsies with an automated device such as the Biopty® gun (Bard Radiology, Covington, Ga.). Use of the Biopty® gun as illustrated schematically in FIG. 1G, requires that the user remove the gun and its attached needle from the body to acquire and remove one core sample. Furthermore, each sample must be manually handled for preparation. Consequently, the volume of tissue that can be acquired is limited by the time consuming nature of the current generation of automated biopsy guns. The present invention allows many samples to be acquired and removed with one insertion of the device into the body and allows the acquisition and removal to occur rapidly with minimum handling. With this type of automation, sampling and/or complete removal of the abnormality is possible.
In a first primary embodiment, the present invention is a biopsy device for acquiring a plurality of sequentially biopsied, discrete samples of tissue comprising: a rotatable retaining fixture; an elongate outer piercing needle having a sharpened distal end for piercing tissue, the elongate outer piercing needle attached to the rotatable retaining fixture such that the sharpened distal end is held in a fixed position within the tissue mass at a predetermined target position, wherein the elongate outer piercing needle has a lateral opening located proximal to the sharpened distal end for receiving a portion of the tissue mass which is positioned adjacent to the lateral opening; an elongate inner cannula disposed coaxially and slidably within the elongate outer piercing needle, the elongate inner cannula having a sharpened distal end for cutting the portion of tissue protruding into the elongate outer piercing needle lateral opening when the elongate inner cannula slides past the lateral opening thereby depositing the portion of cut tissue within the elongate inner cannula proximal to the sharpened distal end; an inner cannula driver connected to the elongate inner cannula and configured to move the elongate inner cannula axially within the elongate outer cannula; and a tissue sample cartridge having a plurality of tissue sample receptacles, the tissue sample cartridge located proximal to a distal end of the elongate outer cannula and configured to receive the portion of cut tissue which is in the elongate inner cannula proximal to the sharpened distal end when the inner cannula driver withdraws the inner cannula from the outer cannula. This embodiment may further comprise an elongate knock out pin disposed coaxially and slidably within the elongate inner cannula, the elongate knock out pin having a closed distal end with a vent hole therein. Additionally, the a vacuum source may be attached to a proximal end of the elongate knock out pin.
In a second primary embodiment, the invention is a biopsy instrument comprising: a first hollow tubular member having a longitudinal axis, a proximal portion, a distal portion, a tissue receiving port positioned laterally a selected distance from the distal portion, and a tissue discharge port positioned a selected distance from the proximal portion; and a tissue sample cassette having a plurality of tissue sample compartments, wherein each of the tissue sample compartments has a tissue receiving port, the tissue sample cassette having a plurality of positions with respect to the first hollow tubular member tissue discharge port such that each of the tissue sample compartment receiving ports may be sequentially aligned with the first hollow tubular member discharge port. This embodiment may further comprise a body having a portion arranged to be mounted to a stereotactic guidance unit; and a rotary drive mechanism mounted to the body and to the proximal portion of the first hollow tubular member. Alternatively, this embodiment may further comprises a first hollow tubular member rotatable retaining fixture coupled to the proximal portion of the first hollow tubular member, wherein rotation of the fixture controls the angular orientation of the laterally disposed tissue receiving port. In yet another alternative embodiment, the first hollow tubular member further comprises a vacuum manifold positioned proximal to the laterally disposed tissue receiving port. Another alternative embodiment further comprises: a second hollow tubular member having: a longitudinal axis, a proximal portion, a distal portion, a tissue cutting portion positioned a selected distance from the distal portion, wherein the second hollow tubular member is positioned coaxially with the first hollow tubular member, the first hollow tubular member tissue receiving port and the second hollow tubular member tissue cutting portion coacting to severe tissue extending through the tissue receiving port. This alternate embodiment may further comprise a second hollow tubular member driving system coupled to the proximal portion of the second hollow tubular member, wherein the second hollow tubular member driving system controls the rotational motion of the second hollow tubular member about the longitudinal axis and the linear motion of the second hollow tubular member along the longitudinal axis. In this embodiment, the second hollow tubular member driving system may further comprise an ultrasonic driver. This alternate embodiment may further comprise an elongate knock out pin disposed coaxially and slidably within the second hollow tubular member, the elongate knock out pin having a closed distal end with a vent hole therein. The elongate knock out pin may further have a vacuum source attached to a proximal end thereof.
In a third primary embodiment, the invention is for a biopsy method comprising the steps of: introducing a hollow tubular member having a laterally disposed tissue receiving port located a preselected distance from a distal portion and a tissue discharge port located at a preselected distance from a proximal portion into a tissue mass to be sampled; severing a tissue sample from the tissue mass which has entered the tissue receiving port; transporting the severed tissue sample through the hollow tubular member to the proximal portion of the hollow tubular member; and depositing the severed tissue sample in one of a plurality of tissue sample compartments in a sample cassette. The method may further comprise the step of rotating the laterally disposed tissue receiving port of the hollow tubular member to a predetermined angular orientation. Alternatively, the method may further comprise the step of applying a vacuum to the laterally disposed tissue receiving port of the hollow tubular member. Additionally, the step of applying a vacuum may further comprise the step of distributing the vacuum uniformly over an area defining the laterally disposed tissue receiving port of the hollow tubular member. The method may further comprise the step of maintaining a record of the location in the tissue mass from which each tissue sample is acquired. In some embodiments, the method further comprises the step of processing the tissue samples for examination without removing them from the tissue sample compartments in the sample cassette.
In a fourth primary embodiment, the invention is a biopsy instrument comprising: a hollow piercing needle having a laterally disposed tissue receiving port at a distal end and a sample discharge port at a proximate end, wherein the hollow piercing needle is mounted on a rotatable positioner for controlling the angular orientation of the tissue receiving port; and a sample cassette having a plurality of compartments coupled to the sample discharge port, wherein each of the plurality of compartments is correlated with a specific angular orientation of the tissue receiving port.
In a fifth primary embodiment, the invention is a biopsy instrument for extracting intact tissue samples from within a body comprising: (a) an elongated primary hollow tube with a closed distal end; (b) a lateral tissue receiving port near the distal end of the elongated primary hollow tube, wherein the lateral tissue receiving port is configured for positioning within the body; (c) a proximal tissue discharge port near a proximal end of the elongated primary hollow tube, wherein the proximal tissue discharge port is configured for positioning outside the body; and. (d) a tissue specimen cassette containing multiple receptacles configured to receive tissue specimens mated to the proximal tissue discharge port. A first alternate embodiment of the fifth primary embodiment may further comprise: (a) an inner hollow tube movably positioned within the elongated primary hollow tube, the inner hollow tube having a sharpened distal end; and (b) an inner hollow tube driver attached to a proximal end of the inner hollow tube, the inner hollow tube driver configured: 1) to move the inner hollow tube past the lateral tissue receiving port thereby cutting off a tissue specimen and thereby positioning the tissue specimen within the inner hollow tube, and 2) to move the inner hollow tube to the proximal tissue discharge port. In some configurations, the inner hollow tube driver is further configured to rotate the sharpened distal end of the inner hollow tube to facilitate cutting or alternatively to oscillate the sharpened distal end of the inner hollow tube to facilitate cutting. Additionally, the first alternate embodiment may further comprise a packing plug located within the distal end of the elongated primary hollow tube; the packing plug shaped to mate with the inside of the distal end of the inner hollow tube to pack the tissue specimen within the inner hollow tube. A second alternate embodiment of the fifth primary embodiment further comprises: (a) an outer hollow tube movably positioned outside the elongated primary hollow tube with a closed distal end, the outer hollow tube having a sharpened distal end; (b) an outer hollow tube driver attached to a proximal end of the outer hollow tube, the outer hollow tube driver configured to move the outer hollow tube past the lateral tissue receiving port at the distal end of the elongated primary hollow tube thereby cutting off a tissue specimen and depositing the tissue specimen within the elongated primary hollow tube; and (c) a driver attached to the proximal end of the elongated primary hollow tube configured to move the elongated primary hollow tube with a closed distal end to the proximal tissue discharge port. In this embodiment, the outer hollow tube driver may be further configured to rotate the sharpened distal end of the outer hollow tube to facilitate cutting or alternatively to oscillate the sharpened distal end of the outer hollow tube to facilitate cutting. A third alternate embodiment of the fifth primary embodiment further comprises an elongate knock out pin disposed coaxially and slidably within the elongated primary hollow tube, the elongate knock out pin having a closed distal end with a vent hole therein. This alternate embodiment may also include a vacuum source attached to a proximal end of the elongate knock out pin. A fourth alternate embodiment of the fifth primary embodiment further comprises a registration mechanism to correlate the orientation of the lateral tissue receiving port with a unique tissue sample cassette sequence number to allow reconstruction of the spatial distribution of the collected tissue specimens. A fifth alternate embodiment of the fifth primary embodiment further comprises a vacuum chamber connected to the lateral tissue receiving port to actively pull tissue into the lateral tissue receiving port in the elongated primary hollow tube. A sixth alternate embodiment of the fifth primary embodiment further comprises a proximal longitudinal depth controlling mechanism connected to the elongated primary hollow tube configured to translate the outer hollow tube to selected depths along the elongate hollow tube's long axis whereby the biopsy instrument can extract multiple intact tissue samples longitudinally from within a target lesion or organ while, at all times, maintaining the instrument within the target. In a seventh alternate embodiment of the fifth primary embodiment, the invention further comprises a proximal rotational drive controlling mechanism connected to the elongated primary hollow tube configured to rotate the elongate hollow tube to selected positions about the elongate hollow tube's long axis whereby the biopsy instrument can extract multiple intact tissue samples radially from within a target lesion or organ while, at all times, maintaining the instrument within the target. In an eighth alternate embodiment of the fifth primary embodiment, the invention further comprises: (a) a pointed distal end on the elongated primary hollow tube with a closed distal end; and (b) a proximal piercing mechanism connected to the elongated primary hollow tube with a closed distal end, the proximal piercing mechanism configured to translate the elongated hollow tube to selected depths along the elongated hollow tube's long axis whereby the biopsy instrument can pierce a target lesion from without the lesion. A ninth alternate embodiment of the fifth primary embodiment further comprises a guidance system for positioning the elongated primary hollow tube which is selected from the group including, endoscopy, computed tomography, ultrasound, fluoroscopy, stereotaxis, and magnetic resonance imaging.
A sixth primary embodiment of the present invention is a biopsy instrument comprising: (a) an elongated primary hollow tube with a closed distal end; (b) a lateral tissue receiving port near the distal end of the elongated primary hollow tube, wherein the lateral tissue receiving port is configured to receive tissue; (c) a vacuum chamber attached to the distal end of the elongated primary hollow tube; and (d) a plurality of communicating holes between the distal end of the elongated primary hollow tube and the vacuum chamber to pull tissue into the elongated primary hollow tube.
A seventh primary embodiment of the present invention is biopsy method for excavating a large volume of tissue from within a body by repetitively removing smaller tissue specimens through a small opening in the body, the small opening just large enough to withdraw one tissue specimen, the method comprising the steps of: (a) introducing an elongated primary hollow tube with a closed distal end into the body, wherein the elongated primary hollow tube has a lateral tissue receiving port near its distal end and a proximal tissue discharge port with the proximal tissue discharge port mated to a tissue specimen cassette containing a plurality of specimen compartments; (b) positioning the lateral tissue receiving port within the body near a target lesion or organ; (c) positioning the proximal tissue discharge port outside the body; (d) cutting a tissue specimen which has entered the tissue receiving port; (e) transporting the cut tissue specimen through the elongated primary hollow tube to the proximal tissue discharge port; and (f) depositing the cut tissue specimen into a receptacle within the tissue specimen cassette. A first alternate embodiment of the seventh primary embodiment further comprises the step of rotating the lateral tissue receiving port to a predetermined angular orientation. A second alternate embodiment of the seventh primary embodiment further comprises the step of translating the lateral tissue receiving port to a predetermined depth within the body. In a third alternate embodiment of the seventh primary embodiment, the method further comprises the step of applying a vacuum to the lateral tissue receiving port to encourage tissue capture. This embodiment may further comprise the step of distributing the vacuum uniformly over an area defining the lateral tissue receiving port. A fourth alternate embodiment of the seventh primary embodiment further comprises the step of maintaining a record of the orientation of the lateral tissue receiving port and the number of the chamber in the tissue specimen cassette to allow special correlation of the origin of each specimen. A fifth alternate embodiment of the seventh primary embodiment further comprises the step of packing the tissue specimen into a transport means with a packing plug. This embodiment may further include the step of ejecting the tissue specimen from the transport means into the tissue specimen cassette. In a sixth alternate embodiment of the seventh primary embodiment, the invention further comprises the step of piercing the target lesion by actively driving the elongated primary hollow tube from without the targeted lesion to within the lesion.
An eighth primary embodiment of the present invention is biopsy device comprising: a housing; a tubular piercing member having a distal pointed end, and a laterally positioned tissue receiving port proximate the distal pointed end which opens into a tissue sample chamber, wherein the tubular piercing member is rotably attached to the housing and held in a fixed position within a tissue mass; a cannular cutting member coacting with the tubular piercing member to cut a first tissue sample from the tissue mass such that the first tissue sample can be transported by the second cutting member to said tissue sample receptacle.
The present invention is an improved automated biopsy system which allows better percutaneous sampling of breast lesions for diagnostic purposes and allows complete removal of small breast abnormalities or removal of other tissue for a variety of reasons percutaneously through a tiny skin incision. Although initially designed for breast biopsies, the system may also be used to biopsy other organs, for example, the prostate.
BRIEF DESCRIPTION OF THE DRAWINGS
The above noted advantages and other characteristic features of the present invention will be apparent through reference to the following detailed description of the preferred embodiments and accompanying drawings, wherein like reference numerals designate corresponding parts and wherein:
FIGS. 1A through 1E show the sequence and errors related to surgical biopsy;
FIG. 1F shows the business end of the True Cut® needle system;
FIG. 1G shows the operational sequence of events for the True Cut® needle system;
FIGS. 1H through 1J show common occurrences surrounding use of the True Cut® needle system;
FIG. 1K shows a perspective view of a first preferred embodiment of the biopsy instrument of the present invention;
FIG. 2 shows a schematic plan view of the biopsy instrument of the present invention shown in FIG. 1K;
FIG. 3 shows individual components of the biopsy instrument shown in FIG. 1K and FIG. 2;
FIG. 4 shows a detailed view of a hollow outer piercing needle and sample cassette;
FIG. 5A shows a cross sectional view of the sample cassette housing and the tissue sample cassette;
FIG. 5B shows a sequence of operating events for the present invention;
FIGS. 6A, 6B, 6C, 6D, 6E, 6F, 6G and 6H illustrate sequential steps in the operation of the biopsy instrument of the present invention;
FIGS. 7A, 7B, 7C and 7D show cross sectional end views of the hollow outer piercing needle piercing the tissue mass in four different angular positions;
FIGS. 8A, 8B, 8C and 8D show cross sectional views of the tissue sample cassette with tissue samples deposited therein for the same four angular positions shown in FIGS. 7A, 7B, 7C and 7D, respectively;
FIGS. 9A, 9B and 9C illustrate a precision procedure for acquiring and tagging multiple tissue samples both along an axis and about the axis with a single entry into the tissue mass being sampled.
FIG. 10 shows an embodiment of a tissue sample cassette having covers over the tissue chambers;
FIGS. 11A and 11B illustrate a first alternate cutting mechanism for the biopsy instrument having a rotation/translation outer cannular cutter;
FIGS. 12A and 12B illustrate a second alternate cutting mechanism for the biopsy instrument having a rotation only outer cannular cutter;
FIGS. 13A, 13B and 13C illustrate an alternate cutting action for the cutting mechanism previously described in connection with FIGS. 1K-6;
FIGS. 14A, 14B and 14C illustrate a third alternate cutting mechanism for the biopsy instrument having receiving ports in both the piercing needle and the cutter whereby the tissue is severed by rotation of the cutter;
FIGS. 15A and 15B illustrate a fourth alternate cutting mechanism for the biopsy instrument having two counter-rotating inner cutters;
FIG. 16 shows a piercing needle with a tissue receiving port having a vacuum manifold;
FIG. 17 shows a perspective view of a second preferred embodiment of the biopsy instrument of the present invention; and
FIG. 18 shows a perspective view of a third preferred embodiment of the biopsy instrument of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1K, 2, 3 and 4 wherein FIG. 1K shows a perspective view of a first preferred embodiment 10 of the biopsy instrument of the present invention, FIG. 2 shows a schematic plan view of the biopsy instrument 10, FIG. 3 shows individual components of the biopsy instrument 10, and FIG. 4 shows a detailed view of a hollow outer piercing needle and sample cassette. Biopsy instrument 10 comprises a housing 14 having a lid 16. The housing 14 is divided into four sections including a sample cassette chamber 20, an outer piercing needle driver chamber 24, an inner cutter driver chamber 28 and a knock out pin driver chamber 32. Mounted in the sample cassette chamber 20 is a cassette housing 36 which contains a tissue sample cassette 40. A hollow outer piercing needle 44 is attached to the cassette housing 36 as is an outer piercing needle elongate indexing gear 48. A distal end of the hollow outer piercing needle 44 includes a point 45. Hollow outer piercing needle 44 also includes a tissue receiving port 46. A piercing needle drive gear 52 attached to a piercing needle drive motor 56 meshes with the piercing needle indexing gear 48. Piercing needle indexing gear 48 is movably mounted within outer needle driver chamber 24 on a piercing needle sliding support 60. A piercing needle linear driver 64 is connected to the piercing needle sliding support 60.
A cannular inner cutter 68 having a cannular inner cutter elongate indexing gear 72 attached to a proximal end is movably positioned coaxially within the hollow outer piercing needle 44. A cannular inner cutter drive gear 76 attached to a cannular inner cutter drive motor 80 meshes with the cannular inner cutter elongate indexing gear 72. Cannular inner cutter elongate indexing gear 72 is movably mounted within inner cutter driver chamber 28 on an inner cutter sliding support 84. An inner cutter linear driver 88 is connected to the inner cutter sliding support 84.
A tubular knock out pin 92 having a tubular knock out pin elongate indexing gear 96 attached to a proximate end is movably positioned coaxially within the cannular inner cutter 68. A tubular knock out pin drive gear 100 attached to a tubular knock out pin drive motor 104 meshes with the tubular knock out pin elongate indexing gear 96. Tubular knock out pin elongate indexing gear 96 is movably mounted within knock out pin driver chamber 32 on a tubular knock out pin sliding support 108. A tubular knock out pin linear driver 112 is connected to the tubular knock out pin sliding support 108. A vacuum connection 116 is located at a proximal end of tubular knock out pin 92.
A control unit 118 (FIG. 2) controls the operation of drive motors 56, 80, 104; linear drivers 64, 88, 112; and a vacuum source connected to port 116. The control unit 118 may be programmed by the user to collect a set of specimens from discreet locations, and is capable of outputting a record of such locations to correlate individual samples to the discreet locations.
A cross sectional view of the sample cassette housing 36 and the tissue sample cassette 40 is shown in FIG. 5A. Tissue sample cassette 40 includes tissue containment chambers 120a, 120b, 120c and 120d. The hollow outer piercing needle 44, cannular inner cutter 68 and tubular knock out pin 92 are shown positioned in tissue containment chamber 120a. Sample cassette 40 includes indexing ridges 124 which cooperate with indexing grooves 128 formed in sample cassette housing 36 to provide precision and repeatable positioning of the sample cassette 40 within the housing 36.
Operation of the biopsy instrument is described with reference to FIGS. 6A through 6H. FIG. 6A illustrates the distal end point 4S of hollow outer piercing needle 44 in position to pierce a tissue sample 132 which is to be sampled. The initial global position of the point 45 with respect to the tissue area being sampled is determined by the overall position of biopsy instrument 10 of the present invention with respect to the patient. For example, the entire biopsy instrument 10 may be mounted on a commercially available stereotactic guidance system (e.g., Fischer), not shown, commonly used in the medical field for accurate positioning of a variety of medical devices with respect to a patient. A detailed description of such a motorized biopsy needle positioner, i.e., stereotactic guidance system, is given in U.S. Pat. No. 5,240,011, issued on Aug. 31, 1993, to Michael Assa, which is hereby incorporated herein by reference. The suspect lesion within the tissue sample 132 which is to be sampled is targeted according to the instructions provided with the stereotactic guidance system. As shown in FIG. 6A, the stereotactic guidance system has positioned the biopsy instrument 10 such that distal end point 45 is immediately adjacent a surface of the tissue sample 132 in which the lesion to be sampled is located. Furthermore, it is object of the guidance system to position the needle assembly such that the center of the lesion is centered within the tissue receiving notch immediately after firing the needle assembly. It will be understood that when the lesion to be sampled is located more deeply within the tissue sample 132, the stereotactic guidance system will advance the point 45 through the surrounding tissue surface and advance the point 45 until it is adjacent the specific lesion region to be sampled.
Once the point 45 is adjacent the specific lesion region to be sampled, fine tuning of the location of the point 45 within the tissue sample 132 is accomplished by control unit 118 which sends signals to linear actuator 64 thus advancing and retracting the hollow outer piercing needle 44 along its axis. As shown in FIG. 6B, linear actuator 64 has advanced the hollow outer piercing needle 44 into the tissue sample 132. Linear actuators 64, 88, 112 may be any of a variety of devices capable of inducing linear motion including solenoids, pneumatic cylinders, potential energy devices such as springs, motors, etc.
As shown in FIG. 6C, after the hollow outer piercing needle 44 has been positioned at the precise location within the tissue 132 at which it is desired to obtain a tissue sample, the control unit 118 actuates a vacuum source which is applied to the vacuum connection 116 of the tubular knock out pin 92 thereby generating a region of low pressure 136 within the hollow outer piercing needle 44. A vent hole 138 in the distal end of the tubular knock out pin 92 provides an air passageway between the hollow interior of the tubular knock out pin 92 and the hollow interiors of the hollow outer piercing needle 44 and the cannular inner cutter 68. The low pressure created by the vacuum source in region 136 facilitates the prolapse of tissue 132a immediately adjacent tissue receiving port 46 into the hollow interior of hollow outer piercing needle 44.
The prolapsed tissue sample 132a is severed from the main tissue mass 132 by the advancement of the cannular inner cutter 68 as shown in FIG. 6D. The advancement of cannular inner cutter 68 is activated by control unit 118 which sends signals to linear actuator 88 thus advancing the cannular inner cutter 68 along its axis within the hollow outer piercing needle 44 past the tissue receiving port 46 thereby severing prolapsed tissue sample 132a from the main tissue mass 132. After being severed from tissue mass 132, the tissue sample 132a is packed into the cannular cutter 68 as it moves forward against pin 41 and rests inside the cannular inner cutter 68. The control unit 118 then activates linear actuator 88 in the reverse direction to withdraw the cannular inner cutter 68 and the tissue sample 132a. Tissue sample 132a is held in the cannular inner cutter 68 by friction with the inner walls of the cannula and by the suction created by the vacuum source and delivered into the region of low pressure 136 by the tubular knock out pin 92. The withdrawal of the tissue sample 132a is illustrated in FIG. 6E.
Tissue sample 132a is deposited in tissue sample cassette 40 as shown in FIG. 6F. The tubular knock out pin 92 is positioned coaxially within the cannular inner cutter 68 and the hollow outer piercing needle 44 such that a distal end of the tubular knock out pin 92 is near the proximal end of the tissue containment chamber 120a. As the cannular inner cutter 68 is withdrawn through the tissue containment chamber 120a, the tissue sample 132a is stopped within the tissue containment chamber 120a by the distal end of the tubular knock out pin 92.
The final release of the tissue sample 132a from the tubular knock out pin 92 into the tissue containment chamber 120a is illustrated in FIGS. 6G and 6H. In FIG. 6G, the vacuum source has been turned off by control unit 118 thereby releasing the tissue sample 132a from the distal end of the tubular knock out pin 92. FIG. 6H shows the tubular knock out pin 92 in a withdrawn position completely clear of the tissue sample cassette 40 and tissue sample 132a resting within the tissue containment chamber 120a.
In some applications, it may be advantageous to obtain a tissue sample as shown in FIGS. 6A-6H without application of a vacuum to the tubular knock out pin 92. In other applications, it may be advantageous to apply vacuum to tissue receiving port 46 through a second dedicated lumen fully described in reference to FIG. 16.
FIGS. 7 and 8 show the cross sectional views indicated in FIG. 6H. These figures illustrate a procedure whereby four samples of tissue mass 132 are acquired from four different angular positions and deposited in sample cassette 40 without removing the hollow outer piercing needle 44 and tissue receiving port 46 from the tissue mass 132. Furthermore, the integrity of each sample is preserved and a record of the location from which each of the four samples is acquired is created by storing the samples in individual sample containment compartments 120. FIGS. 7A, 7B, 7C and 7D show cross sectional end views of the hollow outer piercing needle 44 piercing the tissue mass 132 in four different angular positions. FIGS. 8A, 8B, 8C and 8D show cross sectional views of the tissue sample cassette 40 with tissue samples deposited therein for the same four angular positions shown in FIGS. 7A, 7B, 7C and 7D, respectively.
The cross sectional end view of the hollow outer piercing needle 44 piercing the tissue mass 132 shown in FIG. 7A corresponds to the angular orientation of the hollow outer piercing needle 44 in FIGS. 6A-6H. That orientation is such that the tissue receiving port 46 of hollow outer piercing needle 44 defines an arc 140a within which surrounding tissue sample 132a can prolapse into the hollow outer piercing needle through the receiving port 46. The arc 140a is governed by the shape of receiving port 46 and spans an angular range of from approximately 10:00 o'clock to approximately 2:00 o'clock. Tissue sample 132a is severed from tissue mass 132, transported through hollow outer piercing needle 44 and deposited into sample containment chamber 120a (FIG. 8A) as previously described in reference to FIGS. 6A-6H.
Outer piercing needle drive motor 56 (FIG. 2) rotates the hollow outer piercing needle 44 about its axis 90 degrees to the angular position shown in FIG. 7B. This rotation positions the tissue receiving port 46 adjacent a new region of tissue mass 132 defined by an arc 140b. Additionally, the tissue sample cassette 40 is moved within cassette housing 36 to align the sample containment chamber 120b with the axis of hollow outer piercing needle 44. The arc 140b spans an angular range of from approximately 1:00 o'clock to approximately 5:00 o'clock. Tissue sample 132b is severed from tissue mass 132, transported through hollow outer piercing needle 44 and deposited into sample containment chamber 120b as previously described. Similarly, tissue samples 132c and 132d are acquired from angular positions 140c and 140d, respectively. The arc 140c spans an angular range of from approximately 4:00 o'clock to approximately 8:00 o'clock and arc 140d spans an angular range of from approximately 7:00 o'clock to approximately 11:00 o'clock. It will be understood that the above procedure is illustrative of the general capabilities of the present invention. Rotations about the axis are not limited to 90 degrees but may be of any number of degrees desired. Also, arcs may span more or less than the 4 hour increment described by 140a through 140d.
FIG. 5B is a flow chart which summarizes the operation of the invention as previously described in reference to FIGS. 6A-6H, 7A-7D and 8A-8D. The lesion to be sampled is targeted, activity block 131 (FIG. 6A), followed by piercing of the lesion and maintaining the depth or axial position, activity block 133 (FIG. 6B). The tissue is then actively captured in the tissue receiving port 46, activity block 135 (FIG. 6C). Additionally, the tissue receiving chamber 46 is automatically registered to the sample cassette chamber 120a as indicated by activity block 137. In activity blocks 139 and 141, the tissue specimen 132a is severed from tissue mass 132 and packed into the hollow cutter 66 (FIG. 6D). The severed tissue sample 132a is then transported out of the body as indicated by activity block 143 (FIG. 6E) and placed into the sample cassette chamber 120a as indicated by activity block 145 (FIGS. 6F-6H). If more lesion or biopsy samples are required, decision block 147, the process advances to activity block 149 wherein the sample cassette is advanced to a new sample chamber, then to activity block 151 wherein the tissue receiving chamber 46 is positioned for acquiring another sample (FIGS. 7 and 8). The process then repeats beginning in block 135. If no additional lesion or biopsy samples are required in decision block 147, the process is terminated.
In addition to acquiring multiple tissue samples around the axis of the hollow outer piercing needle 44 with a single entry into the tissue mass 132 as described with reference to FIGS. 6 and 7, the biopsy instrument 10 of the present invention may be used to acquire multiple tissue samples along the axis of the hollow outer piercing needle 44. This procedure is illustrated in FIGS. 9A, 9B and 9C. FIG. 9A shows the tissue receiving port 46 of the hollow outer piercing needle 44 in a first axial position wherein four samples have been removed about the axis from the first axial position as previously described in reference to FIGS. 7 and 8. FIG. 9C illustrates schematically the relative orientation of the four samples ("1", "2", "3" and "4") which have been removed from about the first axial position of the hollow outer piercing needle 44 shown in FIG. 9A. The hollow outer piercing needle 44 is then moved forward along its axis to the second axial position shown in FIG. 9B by the outer piercing needle linear driver 64 (FIG. 2). From the second axial position, four additional samples ("5", "6", "7" and "8") about the axis are removed. Using this procedure, a relatively large volume of tissue can be removed from a prespecified area within tissue mass 132 without having to remove and relocate the biopsy instrument from that prespecified area for each piece of the sample acquired. Additionally, the location from which each piece of tissue is acquired is known with great precision and the locations recorded by storing each piece individually in the tissue sample cassette 40.
Once the tissue samples 132a, 132b, 132c and 132d are loaded into the tissue sample cassette 40, the samples are ready for analysis. FIG. 10 shows an embodiment of the tissue sample cassette 40 which further comprises covers 144 over the chambers 120a, 120b, 120c and 120d. Covers 144 contain the tissue samples within the chambers 120 and protect them from outside contamination during transport to the analysis lab. Thus, during the entire process, the tissue samples never have to be handled individually or manually. Additionally, the samples may be processed for examination while in the tissue sample cassette. For example, if the preparation involves impregnating and embedding the tissue samples in paraffin and slicing them into thin sections, this may be performed with the samples in the cassette.
FIGS. 11A and 11B illustrate a first alternate cutting mechanism for the biopsy instrument 10. In this embodiment, a hollow piercing needle 244 has a pointed distal end 245 and a tissue receiving port 246. The hollow piercing needle 244 is movably positioned coaxially within an outer cannular cutter 268. A tubular knock out pin 292 is movably positioned coaxially within the hollow piercing needle 244. As shown by arrows 294 and 296, the outer cannular cutter 268 is capable of rotational motion about the hollow piercing needle 244 as well as translational motion along their common longitudinal axis. The outer cannular cutter 268 rotational motion is controlled by drive motor 56 and the linear motion along the longitudinal axis is controlled by the linear driver 64. A combination of these two actions provides the cutting action necessary to sever a tissue sample which has prolapsed into the tissue receiving port 246. As with the previous embodiment, the knock out pin 292 may provide vacuum to the tissue receiving port to aid in prolapsing the tissue into the chamber as well as to provide a force to hold the severed sample and transport it through the hollow piercing needle to a sample storage area, such as sample cassette 40 (FIG. 2). In some embodiments, the vacuum holds the tissue sample next to a vent hole in the end of the knock out pin 292 while the knock out pin is withdrawn, dragging the tissue sample with it. It other embodiments, the end of the knock out pin 292 is open and the tissue sample is suctioned through the hollow interior of the tubular knock out pin 292 into a tissue sample receiving area.
FIGS. 12A and 12B illustrate a second alternate cutting mechanism for the biopsy instrument 10. In this embodiment, a hollow piercing needle 344 has a pointed distal end 345 and a tissue receiving port 346. The hollow piercing needle 344 is movably positioned coaxially within an outer cannular cutter 368 which also has a tissue receiving port 376. In operation, the two receiving ports 346 and 376 are aligned thereby allowing tissue adjacent the ports to prolapse into the hollow interior of the piercing needle 344. As shown by arrow 394, the outer cannular cutter 368 is capable of rotational motion about the hollow piercing needle 344. The outer cannular cutter 368 rotational motion is controlled by cutter drive motor 56. Thus, the tissue which has prolapsed into the interior of the piercing needle 344 is severed by rotating the outer cannular cutter 368 about the piercing needle 344, thereby severing the tissue and closing the tissue receiving port 346. A vacuum source applied to the proximate end of the hollow piercing needle 344 suctions the tissue sample through the hollow interior of the hollow piercing needle 344 into a tissue sample receiving area. Alternately, the inner piercing needle 344 containing the tissue sample may be translated out of the body to the cassette 40 as previously described. Translation is controlled by linear actuator 88.
FIGS. 13A, 13B and 13C illustrate an alternate cutting action for the cutting mechanism previously described in connection with FIGS. 1K-6. The cutting action described in FIGS. 1K-6 was a linear slicing of the tissue which had prolapsed into the tissue receiving port 46 by the coaxial linear motion of the cannular inner cutter 68 through the hollow outer piercing needle 44. FIGS. 13A and 13B illustrate the same structure comprising the cannular inner cutter 68 and the hollow outer piercing needle 44. However, the cutting action is modified. As shown by arrows 410 and 412, the cannular inner cutter 68 is capable of rotational motion within the hollow piercing needle 44 as well as translational motion along their common longitudinal axis. The cannular inner cutter 68 rotational motion is controlled by cutter drive motor 80 and the linear motion along the longitudinal axis is controlled by the linear driver 88. A combination of these two actions provides the cutting action necessary to sever a tissue sample which has prolapsed into the tissue receiving port 46. The rotational motion may be continuous or oscillatory, as shown in FIG. 13C. FIG. 13C shows an oscillating pulse pattern for driving the rotary motion of the cutter driver motor 80 first in one direction through a specified angle of rotation followed by rotation in the reverse direction for a specified angle of rotation. In some cases, it has been found that a clockwise rotation of approximately 30 to 40 degrees followed by a counterclockwise rotation of approximately 30 to 40 degrees works well at a frequency of approximately 10 to 40 cycles per second. This action may be achieved with a stepper motor or other type of rotary to oscillating drive mechanism. Likewise, the linear motion along the common longitudinal axis may be linear in one direction or oscillatory. The linear motion is provided by inner cutter linear driver 88 which may be driven by a solenoid for constant linear motion, an ultrasonic transducer or mechanisms referred to above for oscillatory motion or a combination of both. Removal of the severed tissue sample into a tissue receiving area may be by any of the previously described methods.
FIGS. 14A, 14B and 14C illustrate a third alternate cutting mechanism for the biopsy instrument 10. In this embodiment, a hollow piercing needle 444 has a pointed distal end 445 and a tissue receiving port 446. An inner cannular cutter 468 having a tissue receiving port 476 is movably positioned coaxially within the hollow piercing needle 444. In operation, the two receiving ports 446 and 476 are aligned thereby allowing tissue adjacent the ports to prolapse into the hollow interior of the inner cannular cutter 468 (FIG. 14B). As shown by arrow 494, the inner cannular cutter 468 is capable of rotational motion within the hollow piercing needle 444. The inner cannular cutter 468 rotational motion is controlled by cutter drive motor 80. Thus, the tissue which has prolapsed into the interior of the inner cannular cutter 468 is severed by rotating the inner cannular cutter 468 about the piercing needle 444, thereby severing the tissue and closing the tissue receiving port 446 (FIG. 14C). The distal end 470 of the inner cannular cutter 468 is closed, thereby containing the severed sample tissue within the cutter while the cutter 468 is withdrawn from the piercing needle 444 to retrieve the sample. In an alternate embodiment, the distal end 470 of the inner cannular cutter 468 is open. Frictional forces or vacuum applied through the tubular knock out pin 92 contain the severed sample within the notch while the cutter 468 is withdrawn from the piercing needle 444 to retrieve the sample.
FIGS. 15A and 15B illustrate a fourth alternate cutting mechanism for the biopsy instrument 10. In this embodiment, a hollow piercing needle 544 has a pointed distal end 545 and a tissue receiving port 546. A first inner cannular cutter 568 is movably positioned coaxially within the hollow piercing needle 544. A second inner cannular cutter 578 is movably positioned coaxially within the first inner cannular cutter 568. In operation, the first inner cannular cutter 568 rotates in a first direction as indicated by arrow 580 and the second inner cannular cutter 578 counter-rotates in the opposite direction as indicated by arrow 582. The rotation of the two inner cannular cutters 568 and 578 is controlled by the two drive motors 80, 104 (FIG. 2). Additionally, the two inner cannular cutters 568 and 578 move axially within the hollow piercing needle 544 as indicated by arrow 584. The axial motion is controlled by linear drivers 88, 112 (FIG. 2). Removal of the severed tissue sample into a tissue receiving area may be by any of the previously described methods.
FIG. 16 illustrates an embodiment of an outer piercing needle 644 which has a pointed distal end 645, a tissue receiving port 646, and a vacuum manifold 648 adjacent the tissue receiving port. An inner cannular cutter 668 is movably positioned coaxially within the hollow piercing needle 644. The vacuum manifold 648 includes a perforated section 650 having a vacuum chamber 652 on one side and the tissue receiving port 646 on the other side. The vacuum chamber 652 is connected to a vacuum source by a tube 654. In operation, vacuum applied to the manifold 648 is uniformly distributed over the entire receiving port 646 thereby drawing larger and more uniform tissue samples into the port. Severance of the tissue sample in the port from the main tissue mass and transport of the severed tissue to a tissue receiving area may be by several of the methods previously described.
Shown in FIG. 17 is an alternate embodiment of a biopsy instrument 710 of the present invention. A hollow outer piercing needle 744 having a pointed distal end 745, a tissue sample receiving port 746 and vacuum manifold 754 is mounted to a piercing needle collet 766. Piercing needle collet 766 is mounted in an indexing gear 748. A drive gear 752 driven by a motor 756 meshes with the indexing gear 748. A cannular inner cutter 768 is movably positioned coaxially within the hollow outer piercing needle 744. Threads 770 on the outer surface of cannular inner cutter 768 engage threads in a central hole of a cannular inner cutter collet 762. The collet 762 is mounted in a support 764. A drive collet 790 is also attached to the cannular inner cutter and is mounted in an indexing gear 772. A drive gear 776 driven by a motor 780 meshes with the indexing gear 772. Positioned at a proximate end of the cannular inner cutter 768 is a rotary sample cassette 740 having tissue sample chambers 720. Rotary tissue cassette is belt driven by a drive motor 795.
In operation, the hollow outer piercing needle 744 is positioned within a tissue mass at a location where a sample is desired to be acquired. A vacuum is applied to vacuum manifold 648 as discussed in reference to FIG. 16 to actively draw the tissue into the tissue sample receiving port 746. Drive motor 56 controls the angular position at which the tissue sample receiving port 746 is oriented. Drive motor 780 rotates cannular inner cutter 768 such that it rotates and advances along the common longitudinal axis of the piercing needle 744 and the inner cuter 768 into the sample receiving port 746 thereby severing the tissue sample. The forward motion is induced by the coaction of threads 770 and the collet 762. Removal of the severed tissue sample from the receiving port 746 into a tissue receiving area 720 in cassette 740 may be by any of the previously described methods. Drive motor 795 moves the cassette 740 into position to receive a new sample in another one of the chambers 720.
Another embodiment of the invention is shown in FIG. 18. Biopsy instrument 810 comprises a disposable needle portion 802 and a reusable driver portion 804. The reusable driver portion 804 is divided into four sections including a sample cassette chamber 820b, an outer piercing needle driver chamber 824b, an inner cutter driver chamber 828b and a knock out pin driver chamber 832b. A piercing needle drive gear 852 attached to a piercing needle drive motor 856 is mounted in the outer piercing needle driver chamber 824b along with a piercing needle sliding support 860 and a piercing needle linear driver 864. An inner cutter drive gear 876 attached to an inner cutter drive motor 880 is mounted in the inner cutter driver chamber 828b along with an inner cutter sliding support 884 and an inner cutter linear driver 888. A knock out pin drive gear 900 attached to a knock out pin drive motor 904 is mounted in the knock out pin chamber 832b along with a tubular knock out pin sliding support 908 and a knock out pin linear driver 912. A control unit 918 controls the operation of drive motors 856, 880, 904; linear drivers 864, 888, 912; and a vacuum source connected to a port 916.
The disposable needle portion 802 is divided into four sections including a sample cassette chamber 820a, an outer piercing needle driver chamber 824a, an inner cutter driver chamber 828a and a knock out pin driver chamber 832a. Mounted in the sample cassette chamber 820a is a cassette housing 836 which contains a tissue sample cassette 840. A hollow outer piercing needle 844 is attached to the cassette housing 836 as is an outer piercing needle elongate indexing gear 848. A distal end of the hollow outer piercing needle 844 includes a point 845. Hollow outer piercing needle 844 also includes a tissue receiving port 846. A cannular inner cutter 868 having a cannular inner cutter elongate indexing gear 872 attached to a proximate end is movably positioned coaxially within the hollow outer piercing needle 844. A tubular knock out pin 892 having a tubular knock out pin elongate indexing gear 896 attached to a proximate end is movably positioned coaxially within the cannular inner cutter 868. The vacuum connection 916 is located at a proximal end of tubular knock out pin 892.
The disposable needle portion 802 includes the male side of a pin hinge 930a fixed to one side with the corresponding female side of the pin hinge 930b being fixed to a corresponding side of the reusable driver portion 804. When the disposable needle portion 802 and the reusable driver portion 804 are connected by the pin hinge 930 and folded together, the outer piercing needle elongate indexing gear 848 meshes with the piercing needle drive gear 852 and the outer piercing needle elongate indexing gear 848 is inserted into the piercing needle sliding support 860. Similarly, the cannular inner cutter drive gear 876 meshes with the cannular inner cutter elongate indexing gear 872 and the cannular inner cutter elongate indexing gear 872 is inserted into the inner cutter sliding support 884. Likewise, the knock out pin drive gear 900 meshes with the tubular knock out pin elongate indexing gear 896 and the tubular knock out pin elongate indexing gear 896 is inserted into the tubular knock out pin sliding support 908.
Operation of biopsy instrument 810 after the disposable needle portion 802 and the reusable driver portion 804 have been connected by the pin hinge 930 and folded together is the same as the operation of embodiment 10 as shown in FIGS. 1K-4 and described previously. The separation of driver portion 804 from the needle portion 802 is advantageous in that the needle portion may now be disposed of after use and the driver portion, which does not become contaminated during use and does not require patient contact, can be reused, thereby reducing the cost of the device.
The apparatus and method of the present invention for a Method and Apparatus for Automated Biopsy and Collection of Soft Tissue described herein were developed primarily for breast biopsy. However, the invention may also be useful for other types of biopsies. While the above description comprises embodiments of the invention as applied to breast biopsy, there are other applications which will be obvious to those skilled in the art.
The apparatus and method of 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. | A method and device for the automated biopsy and collection of soft tissue having a piercing needle with a receiving port to trap tissue prior to cutting. A motor drive directs and positions the tissue receiving port at a lesion site in arbitrary positions about and along the longitudinal axis of the device. A cutter advances into the receiving chamber and severs tissue which has prolapsed into the receiving port. The severed tissue is then removed from the receiving port without removing the piercing needle receiving port from the lesion site, thus allowing for the accurate, rapid removal of an arbitrary number of core samples with only one insertion. A tissue sample cassette provides storage for the samples as well as a means for coding and decoding the location from which the samples were obtained. Together, these features allow for more accurate and complete sampling of large lesions, for the complete removal of small lesions or removal of other tissue for a variety of reasons. | 0 |
THE BACKGROUND OF THE INVENTION
1. The Technical Field
The invention pertains to a spur wheel with spur teeth for a chain drive assembly of a tracked vehicle, on which teeth the guide elements of a chain roll during the operation of the chain drive assembly.
2. The Prior Art
Spur wheels for the chain drive assemblies of tracked vehicles are generally known. A chain drive assembly for a tracked vehicle, especially for a ski slope grooming vehicle, has a spur wheel on each side of the chassis, which functions as a drive wheel for the chain on each side. The spur wheel in question has the shape of a star or gearwheel and is driven by a hydraulic drive system. The spur teeth of the star-shaped or gearwheel-shaped spur wheel engage in positive fit with corresponding guide elements on the associated chain, which travels around the spur wheel. For this purpose, the spur wheel is preferably positioned on the first or last axle of the chain drive so that it is located at the reversal point of the chain. The positive engagement and the rolling of the guide elements of the chain on the spur teeth of the spur wheel cause the spur wheel and/or the guide elements of the chain to wear down. As a result, the driving comfort and operation of the chain drive assembly can be negatively affected.
SUMMARY OF THE INVENTION
The task of the present invention is to create a spur wheel of the type indicated above which makes it possible for the chain drive assembly to function satisfactorily and comfortably over a long period.
This task is accomplished in that certain areas of the spur teeth which come in contact with the rolling area of the guide elements are designed as removable, replaceable parts. The spur teeth of the spur wheel are therefore provided with replaceable parts in the areas susceptible to wear, which are the areas where the guide elements roll, i.e., the areas of the teeth on the circumference with which these guide elements engage. These replaceable parts can be replaced when they wear out without the need to replace the entire spur wheel. Thus, when it is necessary to renew the contact surfaces of the spur teeth on the spur wheel, the cost and the time required for such work is considerably reduced. The replaceable parts are preferably made of wear-resistant material.
In an elaboration of the invention, the replaceable parts are designed as separate, individual parts. All of the replaceable parts are preferably of the same design, so that only a single mold is required to produce them.
In a further elaboration of the invention, at least one fastening means is provided to attach the replaceable parts to the spur teeth. The replaceable parts can be held in place on the spur teeth either by separate fastening means or by a single, common fastening means.
In a further elaboration of the invention, a locking rim, which holds all of the replaceable parts in place jointly, is provided as the fastening means, which is detachably connected to the spur wheel. The locking rim is in working connection with all the replaceable parts. The locking rim preferably secures the replaceable parts against an opposing stop permanently attached to the spur wheel.
In a further elaboration of the invention, the replaceable parts are located in the bottom land areas between the tips of adjacent teeth. This design is based on the realization that the areas subjected to the most wear are the areas at the bottoms of the gaps between the spur teeth. By comparison, the tips of the teeth are subjected to practically no wear.
In a further elaboration of the invention, the replaceable parts can be slid parallel to the rotational axis of the spur wheel into the bottom land areas. After the replaceable parts have been pushed into working position, their surfaces are preferably flush and aligned with the surfaces of the tips of the adjacent teeth. The spur toothing is thus provided with recesses in the bottom lands between the tips of two adjacent teeth, so that the replacement parts in question can be slid parallel to the rotational axis of the spur wheel in positive fit between the tip sections of the teeth.
In a further elaboration of the invention, a positioning stop acting in the slide-in direction is provided for each replaceable part. With respect to the direction in which the replaceable parts are slid in, this positioning stop is preferably located at the rear of the associated recess, so that each replaceable part can be slid parallel to the rotational axis of the spur wheel up as far as the positioning stop, and when in this working position, the replaceable part will be flush on all sides with the adjacent sections of the spur wheel such as the tooth tip sections, the front end surface of the spur wheel, the positioning stop, etc.
In a further elaboration of the invention, the replaceable parts are connected to each other to form a single unit. The replaceable parts are preferably connected to a circumferential rim to form a single unit, which rim can be pushed coaxially onto the spur wheel in such a way that, as the rim is being pushed on, the replaceable parts simultaneously enter the associated recesses in the spur toothing.
BRIEF DESCRIPTION OF THE DRAWING
Additional advantages and features of the invention can be derived from the claims and from the following description of a preferred exemplary embodiment of the invention, which is illustrated additionally on the basis of the single FIG.
FIG. 1 shows an exploded view, in perspective, of an embodiment of a spur wheel according to the invention for a chain drive assembly of a ski slope grooming vehicle.
FIG. 2 shows a front elevation of the spur wheel in an assembled configuration.
FIG. 3 shows a side section of the spur wheel of FIG. 2 , as seen along lines 3 — 3 of FIG. 2 .
DETAILED DESCRIPTION OF THE INVENTION
A tracked vehicle in the form of a grooming vehicle for ski slopes has a chain drive assembly of the type basically known in and of itself, which is provided on each side with a chain, which serves to move the vehicle over the ground. Each chain is guided by means of several wheels on each side of the chassis. One of these wheels, preferably the one on the axle with is either first or last in the travel direction, is intended to serve as the drive wheel for the chain in question and is designed as a spur wheel 1 . The corresponding spur wheel for each chain is positioned at the reversal point of the chain so that the chain will wrap around approximately half of the circumference of the spur wheel 1 .
To achieve positive engagement between the chain and the spur wheel and thus to ensure the secure and uniform transmission of the drive force from the spur wheel to the chain, the spur wheel 1 is provided around its outside circumference with spur toothing 3 - 5 , which is described in greater detail below. In a manner known basically in and of itself, the corresponding chain has guide elements, which, as the chain reverses direction around the spur wheel, engage in the spur teeth and thus allow the spur wheel 1 to drive the chain in a positive manner.
The spur toothing of the spur wheel 1 has, first, a plurality of tips 3 and, second, a plurality of bottom lands 4 , located between the tips. The spur toothing is ring-shaped and is provided around its inside circumference with a ring-shaped flange 12 . The ring-shaped flange 12 is provided with a plurality of fastening holes (not numbered), by means of which the spur toothing 3 - 5 and the ring-shaped flange 12 can be attached to the hub of the spur wheel 1 .
The tips 3 of the spur teeth are designed in the shape of caps with step-like shoulders projecting out over the bottom lands 4 . As a result, a trough-like recess is formed in each bottom land 4 . The step-like shoulders of the cap-like tips 3 form the boundaries of these recesses at the top of the flanks.
Shell-like replaceable parts 5 can be inserted into the recesses in the bottom lands 4 . The replaceable parts 5 are made of wear-resistant material, preferably of a wear-resistant plastic. Their shape is designed so that they bed down smoothly in the trough-like recesses in the bottom lands 4 and so that their surfaces are flush and aligned with the surfaces of the adjacent tips 3 . After the replaceable parts 5 have been inserted into the bottom lands 4 , a continuous, flush transition is obtained between the surfaces of the tips 3 and the surfaces of the replaceable parts.
The replaceable parts can be slid parallel to the rotational axis of the spur wheel 1 from the common, front-end surface into the corresponding recesses of the bottom lands 4 with a slight amount of play. At the rear, a positioning stop 6 in the form of the edge of a web is assigned to each bottom land 4 , this stop being either an integral part of the spur toothing or a part connected permanently to it in some suitable way. Each replaceable part 5 is equipped with a contact web 7 both at its front edge and also at its rear edge. Each replaceable part 5 is symmetric in design, so that it can be pushed in the same way into the appropriate recess from either side. After the replaceable part 5 has been slid in its working position, its contact web 7 overlaps the rear positioning stop 6 of the associated bottom land 4 .
On the front surface of the spur toothing opposite the positioning stop 6 , a locking rim 8 is provided, which has a corresponding spur tooth contour, and which secures the replaceable parts 5 in the axial direction and locks them in place from the front surface of the spur toothing. The locking rim 8 has an inner circumference with a diameter which is designed to fit onto a ring-shaped shoulder 13 in the area of the spur toothing, so that, after the locking rim 8 has been pushed into its working position, it rests on this ring-shaped shoulder 13 and lies flush with it. The cap-like tips 3 also project slightly in the axial direction toward the front surface, the extent of this projection corresponding to the thickness of the locking rim 8 . Tip contours of the locking rim 8 are matched in such a way to the pitch and shape of the cap-like tips 3 that the tip contours of the locking rim rest flush against the associated projecting sections of the tips 3 . The bottom land contours of the locking rim 8 lying between the tip contours are matched to the radius of curvature of the stop webs 7 of the replaceable parts 5 . The corresponding bottom land contours of the locking rim 8 therefore positively lock each replaceable part 5 in place and secure each part axially in place in the assembled state.
To install the locking rim 8 , a plurality of fastening means in the form of fastening screws 9 is provided, which screws can be screwed into threaded holes 11 in the front end surface of the spur wheel 1 . Corresponding through-openings 10 are provided in the locking rim 8 to receive the fastening screws 9 .
To replace the replaceable parts 5 , the locking rim 8 is easily detached and then pulled axially off the spur toothing. Then the replaceable parts 5 can be pulled out by hand axially from the corresponding recesses of the bottom lands 4 and replaced with new parts. These new replaceable parts are then fixed in place again in the same way by the locking rim 8 and the fastening screws 9 . | A spur wheel for the chain drive assembly of a tracked vehicle on which the guide elements of a chain roll during the operation of the chain drive assembly is provided. Certain parts of the spur teeth which come in contact with the rolling area of the guide elements are designed as removable, replaceable parts. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional Application No. 61/485,382 filed May 12, 2011, the disclosure of which is incorporated in its entirety by reference herein.
TECHNICAL FIELD
[0002] A template bracket for a part holding fixture that is used to hold parts between operations on a manufacturing line.
BACKGROUND
[0003] Manufacturing and assembly lines may be loaded and unloaded by robotic devices. The robotic devices may pick up work pieces from a fixture or holding device and load them into an operation in a press, a welder, or the like. Between operations, a robot may unload the part and place it on another fixture.
[0004] A variety of different parts may be processed on the same manufacturing line. The parts processed on a line may have different shapes that require differently shaped templates on the fixtures to support the parts. Manufacturing lines may be changed over relatively frequently to accommodate different part styles that have different shapes and require different fixture locating points. The templates retained by the template holder brackets must be locked in place. Properly locating fixture templates minimizes the risk of damage to the parts as a result of the parts being placed upon improperly located fixture templates.
[0005] Some prior art fixture templates were secured to brackets by means of two pins that are inserted through a wall of the bracket and into corresponding holes in the base of the template. With this approach, workers may inadvertently fail to insert one or both pins leaving the template in an unstable condition. The pins are generally removed completely from the bracket and set aside until a new template is to be secured to the bracket. The pins may be misplaced or lost when they are removed from the bracket.
[0006] In a modification of the template, a slot may be provided in the template base that receives a pin that is permanently secured to one end of the bracket. The template base is then secured by inserting a removable pin into the side of the bracket and the template base to hold the template base in place. This approach permits one of the removable pins that is generally required to hold the template in the bracket to be eliminated, but still leaves one removable pin that is required to lock the template into the bracket.
[0007] Applicants' invention is directed to solving the above problems relating to fixture templates that are secured to brackets by one or more removable pins.
SUMMARY
[0008] According to one aspect of this disclosure, a template bracket assembly is provided for holding a template for a part holding fixture in a manufacturing operation. The template bracket assembly comprises a bracket defining a slot for receiving the template. A pressure pin assembly retained by the bracket includes a pin that may be shifted between a locking position and a released position. A spring element biases the pin into the locking position. The template is retained in the bracket when the pin is in the locking position. The template is released from the bracket by shifting the pin to the released position without removing the pin from the bracket.
[0009] According to other aspects of the disclosure, the pin may define a ramp surface on a distal end of the plunger that facilitates disengaging the second portion of the plunger from the template. The ramp surface may form a crowned end of the plunger, or alternatively, the ramp surface may be a flat beveled surface that is contiguous with the distal end of the plunger.
[0010] The pressure pin assembly may further comprise a support member that engages a surface formed inside a housing that is engaged by the pin that forms a pin assembly. The support member may be adjusted to change the effective length of the pin assembly. Changing the length of the pin assembly changes the extent that the pin protrudes into the slot and the extent that the spring element biases the pin.
[0011] The template bracket assembly may further comprise a clip engaging a support plate that is part of the bracket and that is attached to the pressure pin assembly. A flange extends radially outwardly from the pressure pin assembly. The support plate defines a receptacle hole and also defines a recess about the receptacle hole that receives the flange so that the pressure pin assembly may be secured to the support plate between the clip and the flange.
[0012] The pressure pin assembly may further comprise a handle that is attached to an outside end of a shaft that extends through the pressure pin assembly and is attached to the pin. The pressure pin assembly may define a seat that receives the handle in the locking position. The handle may be pulled from the seat to move the pin to the released position without separating the pressure pin assembly from the bracket.
[0013] According to another aspect of the disclosure, a pressure pin assembly is provided for a template bracket that holds a template for a part holding fixture in a manufacturing operation. The template bracket comprises a support plate defining a receptacle hole that receives the pressure pin assembly, a back-up plate disposed in a parallel orientation spaced from the support plate. A spacer may be disposed between the support plate and the back-up plate. The support plate, spacer and back-up plate are secured together in a fixed relationship. The pressure pin assembly includes a plunger and a housing defining a bore that receives a first portion the plunger in one end of the housing with a second portion of the plunger extending from the housing. The housing is assembled to the support plate with the second portion of the plunger protruding from the support plate toward the back-up plate. A biasing element, such as a spring, engages the plunger and biases the plunger toward the back-up plate. The template may be inserted between the support plate and the back-up plate. The template defines a recess that at least partially receives the second portion of the plunger to temporarily retain the template in a fixed position. The template may be removed from the template bracket by rotating the template about an axis radially spaced from the plunger to disengage the second portion of the plunger from the recess against the biasing force of the biasing element.
[0014] According to further aspects of the disclosure, the recess in the template may be a hole that extends through the template. The plunger may define a ramp surface on a distal end of the plunger that facilitates disengaging the second portion of the plunger from the template.
[0015] The pressure pin assembly may further comprise a support bolt having a head that engages a shoulder formed inside the bore. The plunger may define a threaded bore on an inner end of the plunger that receives the support bolt to form a plunger assembly. The support bolt may be rotated to change the effective length of the plunger assembly and thereby change the extent that the plunger protrudes from the support plate and the extent to which the biasing element biases the plunger.
[0016] The pressure pin assembly may further comprise a clip engaging an outer surface of the support plate that attaches to an outer surface of the housing and a flange extending radially outwardly from the housing. The support plate may define a recess about the receptacle hole that receives the flange so that the housing may be secured to the support plate between the clip and the flange. The clip may be a spring clip, the flange may be a circular rim, and the recess may be a circular recess that receives the rim.
[0017] Alternatively, the pressure pin assembly may further comprise a handle that is attached to an outside end of a pin that extends through the housing with an inside end of the pin being attached to the plunger. The housing may define a seat that receives the handle in a locking position in which the plunger is received in the recess in the template. The handle may be pulled from the seat defined by the housing to withdraw the plunger from the recess in the template and moved to an unlocking position.
[0018] A method is disclosed for assembling a template to a bracket that defines a slot for receiving the template and a pressure pin assembly that is attached to the bracket. The method may comprise a first step of inserting the template into the slot. The template may then be located relative to the bracket by aligning the pressure pin assembly with a recess defined in the template. A movable pin of the pressure pin assembly is shifted in a direction that is normal to a surface of the template that defines the recess. The movable pin locks the template within the bracket when the pin is partially received in the recess. The template is removed from the slot by moving the template within the slot perpendicular to the direction that the pin is biased.
[0019] According to other aspects of the method, a locating pin may be provided on the bracket and the template may define a slot. The step of inserting the template into the slot may further comprise placing the template in the bracket with the slot receiving the locating pin. The template may then be rotated within the slot until the pin is partially received in the recess. The step of removing the template from the slot may further comprise rotating the template about the locating pin to separate the pin from the recess. The movable pin may include a beveled surface that functions as a ramp surface for moving the pin against the force of a spring that biases the movable pin in a direction normal to the surface of the template that defines the recess.
[0020] Alternatively, the movable pin may include a handle that is attached to an outside end of the pin with an inside end the pin being attached to the movable pin. A seat may receive the handle in a locking position in which the pin is received in the recess in the template. The step of shifting the movable pin may further comprise placing the handle in the recess. The step of removing the template from the slot may further comprise pulling the handle from the seat to withdraw the pin from the recess in the template. By pulling the handle, the pin is moved to a release position while keeping the pressure pin assembly attached to the bracket.
[0021] These and other aspects of the disclosure will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a fragmentary perspective view of a part holding fixture showing a template supported by a bracket on a rail of the fixture;
[0023] FIG. 2 is a perspective view of a template holder bracket;
[0024] FIG. 3 is an exploded perspective view of a template holder bracket and spring pin;
[0025] FIG. 4 is a cross-sectional view taken along the line 4 - 4 in FIG. 2 of the bracket and the spring pin;
[0026] FIG. 5 is a top plan view of a template holder bracket and spring pin;
[0027] FIG. 6 is a front elevation view of a template holder bracket and spring pin;
[0028] FIG. 7 is a side elevation view of a template holder bracket and spring pin; and
[0029] FIG. 8 is an exploded perspective view of an alternative embodiment of a template holder bracket and spring pin.
DETAILED DESCRIPTION
[0030] A detailed embodiment of the present invention is disclosed in this application. The disclosed embodiment is merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed in this application are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the present invention.
[0031] Referring to FIG. 1 , a bracket 10 is shown with a template 12 that has a part engaging surface 14 . The template 12 is positioned above the bracket 10 , ready to be installed in the bracket. The template 12 is used to support a part (not shown) in a manufacturing process between manufacturing operations. The bracket 10 is secured to a base rail 16 of a fixture that supports the template 12 and holds the part at a convenient height.
[0032] The template 12 is secured to the bracket 10 by a pressure pin assembly 18 and a fixed pin 20 . The template 12 has a template base portion 22 that is engaged by the pressure pin assembly 18 and that also receives the fixed pin 20 . A hole 24 , or recess, is provided in the template base portion 22 that is engaged by the pressure pin assembly 18 . An angled slot 26 is provided in a vertically extending edge 28 of the template 12 that receives the fixed pin 20 . The edge 28 is the leading edge of the template base portion 22 when the template 12 is inserted into the bracket 10 . A rounded corner 30 is provided on the lower corner of the template base portion 22 below the angled slot 26 . The rounded corner 30 provides clearance for rotation of the template 12 about the fixed pin 20 . During installation, the template 12 is rotated about the fixed pin 20 until the pressure pin assembly 18 is received in the hole 24 . The illustrated hole 24 is a through hole, however, it would be possible to provide a recess that does not extend through the entire thickness of the template base portion 22 .
[0033] A base surface 32 of the template base portion 22 may include a recess for receiving one or more locating pins, or screw heads, as will be more fully described below with reference to FIGS. 3 and 5 .
[0034] Referring to FIG. 2 , a bracket 10 is shown to be comprised of a support plate 34 that is connected to a back-up plate 36 through a spacer plate 38 . The support plate 34 supports the pressure pin assembly 18 . The back-up plate 36 backs up the template base portion 22 (as shown in FIG. 1 ) against the force applied by the pressure pin assembly 18 . The spacer plate 38 spaces the support plate 34 and back-up plate 36 apart by the width of the template base portion 22 . As shown in FIG. 2 , a plunger 40 of the pressure pin assembly 18 protrudes slightly into the space between the support plate 34 and the back-up plate 36 to exert a biasing force on one side of the template base portion. The plunger 40 has a crowned end 42 that is beveled or generally convex in shape. The crowned end 42 provides a ramp surface that facilitates insertion of the template 12 , as shown in FIG. 1 . A pin housing 48 extends outwardly from the support plate 34 .
[0035] A pin housing 48 extends through a hole 50 defined in the support plate 34 . The support plate 34 and back-up plate 36 are securely fastened together by means of bolts 52 and locating pins 54 that secure the back-up plate 36 , as shown in FIG. 2 , to the spacer plate 38 .
[0036] Referring to FIGS. 3 and 4 , an exploded perspective view and a cross-sectional view of the pressure pin assembly 18 are provided to illustrate the structure and function of the pressure pin assembly 18 . The pin housing 48 is inserted from the inside of the support plate 34 through the hole 50 . The plunger 40 is supported within the housing 48 with its crowned end 42 extending inboard of the support plate 34 . A helical spring 56 is received about a support bolt 58 . The support bolt 58 is received in a threaded hole 60 , shown in FIG. 4 , formed in the plunger 40 . The spring 56 engages the plunger 40 about the support bolt 58 on one end and on the other end engages a shoulder 62 , or lip, formed within the housing 48 . A bolt head 64 is received within the housing 48 on the opposite side of the shoulder 62 from the plunger 40 . It is preferred that the pressure applied by the pressure pin assembly 18 be set at a predetermined level established by the selection of the spring 56 . The spring force selected should permit insertion and removal of the template 12 with a controlled level of force that provides a rigid holding force, but a force that may be easily overcome by rotating the template 12 about the fixed pin 20 . As the template is rotated, the template base 22 shifts the plunger 40 that compresses the spring 56 .
[0037] The pressure pin assembly 18 is secured to the support plate 34 by a spring clip retainer 66 that captures the support plate 34 between a rim 67 of the pin housing 48 and the spring clip retainer 66 that is received in a slot 68 formed on the exterior of the pin housing 48 .
[0038] Referring to FIG. 3 , the back-up plate 36 is secured by bolts 52 and locating pin 54 to the spacer plate 38 . Either the support plate 34 or back-up plate 36 may be disassembled from the spacer plate 38 when the pressure pin assembly 18 is secured within the hole 50 provided in the support plate 34 . The pin housing 48 is inserted from the inside of the support plate 34 into the hole 50 . The pressure pin assembly 18 is secured on the outer side of the support plate 34 by the spring clip retainer 66 . Before assembling the pressure pin assembly 18 to the support plate 34 , the plunger 40 , helical spring 56 and support bolt 58 are assembled together and inserted into the pin housing 48 . When the pressure pin assembly 18 is assembled to the support plate 34 , the crowned end 42 of the plunger 40 extends slightly into the space defined between the support plate 34 and the back-up plate 36 . Bolts 52 and locating pins 54 are used to secure the support plate 34 to the spacer plate 38 . The fixed pin 20 is secured between the support plate 34 and the back-up plate 36 . The fixed pin 20 and pressure pin assembly 18 are generally aligned with their central axes aligned horizontally as shown in the illustrated embodiment.
[0039] Referring to FIGS. 3 and 5 , the spacer plate 38 has a top surface 70 that includes a plurality of sequencing holes 72 . The sequencing holes are adapted to receive a screw or pin that is matched to a recess (not shown) formed on the base of a template 12 so that the templates 12 are assured to be assembled to the desired bracket 10 .
[0040] Referring to FIG. 5 , the bracket 10 , pressure pin assembly 18 and fixed pin 20 are shown assembled together. The crowned end 42 is shown extending inwardly from the support plate 34 . The pressure pin assembly 18 is assembled to the support plate 34 and extends outwardly from the support plate 34 . The fixed pin 20 is fixedly secured between the support plate 34 and the back-up plate 36 . The sequencing holes 72 may be used to receive a pin or screw to coordinate assembly of the desired template 12 to the bracket 10 .
[0041] Referring to FIG. 6 , the bracket 10 , pressure pin assembly 18 and fixed pin 20 are shown assembled together. The crowned end 42 is shown extending inboard of the support plate 34 . The fixed pin 20 is shown extending between the support plate 34 and the back-up plate 36 . The spring clip retainer 66 is shown securing the pressure pin assembly 18 to the support plate 34 .
[0042] Referring to FIG. 7 , the support plate 34 is shown with the pressure pin assembly 18 and fixed pin 20 . The bolts 52 and locating pins 54 are shown that are used to secure the support plate 34 to the spacer plate 38 , as shown in FIGS. 1-6 .
[0043] Referring to FIG. 8 , an alternative embodiment of a locking pin 80 is illustrated with the bracket 10 disclosed with reference to FIGS. 1-7 above. The same reference numerals are used with the corresponding parts that are common to both embodiments. The locking pin 80 includes a plunger 82 that has an end surface 84 and a beveled ramp surface 86 on a distal end of the plunger 82 . The plunger 82 is telescopically received in a bore 90 defined by a plunger housing 92 . The plunger housing 92 is received within an opening 50 defined in the support plate 34 . The support plate 34 and back-up plate 36 are securely fastened together by means of bolts 52 and locating pins 54 that secure the back-up plate 36 , as shown in FIG. 2 , to the spacer plate 38 .
[0044] The plunger housing 92 is inserted into the support plate 34 through the hole 50 . The plunger 82 is supported within the plunger housing 92 with the end surface 84 and the beveled ramp surface 86 extending inboard of the support plate 34 . A helical spring 94 is received about a T-shaped handle 96 that includes a shaft portion 98 and a handle portion 100 . The shaft portion 98 is inserted in the bore 90 and a hole 102 formed in the plunger housing 92 . The shaft portion 98 is secured in a hole 104 formed in the plunger 82 .
[0045] The spring 94 engages the plunger 82 about the shaft portion 98 on one end and on the other end engages a base 106 of the bore 90 formed in the plunger housing 92 . Pressure applied by the locking pin 80 is limited to a predetermined level established by the selection of the spring 94 . The spring force selected should permit the plunger 82 to be withdrawn by pulling the handle portion 100 with a controlled level of force that provides a rigid holding force. However, the level of force must be able to be easily overcome by pulling the handle portion 100 .
[0046] The handle portion 100 is received in a V-shaped recess 108 defined in the back end 110 of the plunger housing 92 when the plunger 82 is in a locking position. In the locking position, the plunger 82 may be received in the hole 24 formed in the template 12 to hold the template 12 in position as previously described with reference to FIG. 1 . The handle portion 100 may be withdrawn and rotated to an unlocked position with the handle portion 100 held out of the V-shaped recess 108 to hold the plunger 82 retracted into the plunger housing 92 . If desired, a smaller recess (not shown) may be provided on the back end 110 of the plunger housing 92 to hold the handle portion 100 in the unlocked position.
[0047] The locking pin assembly 80 is secured to the support plate 34 by a spring clip retainer 66 that captures the support plate 34 between a rim 112 of the plunger housing 92 and the spring clip retainer 66 that is received in a slot 114 formed on the exterior of the plunger housing 92 .
[0048] Referring to FIGS. 3 and 8 , the back-up plate 36 is secured by bolts 52 and locating pin 54 to the spacer plate 38 . Either the support plate 34 or back-up plate 36 may be disassembled from the spacer plate 38 when the locking pin assembly 80 is secured within the hole 50 provided in the support plate 34 . The plunger housing 92 is inserted from the inside of the support plate 34 into the hole 50 . The locking pin assembly 80 is secured on the outer side of the support plate 34 by the spring clip retainer 66 . Before assembling the locking pin assembly 80 to the support plate 34 , the plunger 92 , helical spring 94 and T-shaped handle 96 are assembled together and inserted into the plunger housing 92 . When the locking pin assembly 80 is assembled to the support plate 34 , the end surface 84 and the beveled ramp surface 86 of the plunger 82 extend slightly into the space defined between the support plate 34 and the back-up plate 36 . Bolts 52 and locating pins 54 are used to secure the support plate 34 to the spacer plate 38 . The fixed pin 20 is secured between the support plate 34 and the back-up plate 36 . The fixed pin 20 and locking pin assembly 80 are generally aligned with their central axes aligned horizontally as previously described.
[0049] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention. | A template holder bracket and method of assembling and disassembling a template from the bracket. The bracket has a spring pin assembly that is secured to the bracket that holds the template in a locked position. The spring pin assembly includes a pin, a housing and a spring that biases the pin into engagement with the template. The template may be removed by rotating the template against a ramp surface on the pin assembly that disengages the pin from the template against the biasing force of the spring. | 8 |
BACKGROUND OF THE DESCRIPTION
The invention relates to a method and device for diagnosing deviations in a single cylinder lambda control in an internal combustion engine having at least two cylinders and an exhaust gas sensor designed as a broadband lambda sensor, wherein a pump current is evaluated by means of a pump cell and said pump current is used at least temporarily for an individual cylinder lambda control.
A lambda control in combination with a catalytic converter is today the most effective emission control method for the Otto engine. The use of a three-way or selective catalytic converter is particularly effective. This kind of catalytic converter has the capacity to degrade hydrocarbons, carbon monoxide and nitrogen oxides up to more than 98% in the event that the engine is operated in a range of approximately 1% around the stoichiometric air-fuel ratio whereat λ=1. The lambda value thereby indicates how far the actual, present air-fuel mixture deviates from the value λ=1, which corresponds to a mass ratio of 14.7 kg air to 1 kg gasoline theoretically necessary for complete combustion, i.e. the lambda value is the quotient from the air mass supplied and the theoretically required amount of air. In the case of excess air, λ>1 (lean mixture). In the case of excess gasoline, λ<1 (rich mixture).
When a lambda control is being performed, the exhaust gas is measured and the fuel quantity supplied is immediately corrected in accordance with the measurement result by means of a fuel injection system.
Lambda probes are used as detecting elements, which can be designed on the one hand as a so-called two-point lambda probe or discrete-level sensor and on the other hand as a continuous lambda probe or broadband lambda probe. The effect of these lambda probes is based in a manner known per se on the principle of a galvanic oxygen concentration cell with a solid state electrolyte. The characteristic curve of a two-point lambda probe has a sharp drop in the probe voltage at λ=1. For that reason, a two-point lambda probe, which is usually mounted directly behind the exhaust manifold, essentially allows only for the distinction between rich and lean exhaust gas. On the other hand, a broadband lambda probe permits the exact measurement of the lambda value in the exhaust gas over a wide range around λ=1. Both types of lambda probe consist of a ceramic sensor element, a protective tube as well as cables, a plug and the connections between these elements. The protective tube consists of one or a plurality of metal cylinders having openings. Exhaust gas enters through said openings by means of diffusion or convection and travels to the sensor element. The sensor elements of the two types of lambda probes vary thereby in the construction thereof.
The sensor element of a two-point lambda probe consists of an oxygen ion-conductive electrolyte, in the interior of which a cavity filled with a reference gas is situated. The reference gas comprises a certain constant oxygen concentration but otherwise no oxidizing or reducing constituents. In many cases, the reference gas is air. Electrodes, which are connected to plug contacts via cables, are mounted on the outside of the electrolyte which is in contact with the exhaust gas as well as on the inside of the cavity. According to the Nernst principle, an electrical voltage occurs across the electrolyte, denoted below as Nernst voltage which is determined by the concentration of oxidizing and reducing exhaust gas components in the exhaust gas and in the reference gas. If besides oxygen there are no oxidizing or reducing exhaust gas components in the exhaust gas, the Nernst voltage is described by the equation
U Nernst =U Ref −U Abgas =( R*T/ 4 *F )* In ( p 02,Ref /p 02,Abgas )
In this equation, U Ref stands for the electrical potential on the reference gas side, U Abgas for the potential on the exhaust gas side, p 02,Ref and p 02,Abgas for the oxygen partial pressure in the reference gas or respectively the exhaust gas, T for temperature, R for the general gas constant and F for the Faraday constant. The Nernst voltage can be tapped via the plug contacts and represents the signal of the two-point lambda probe.
The sensor element of a broadband lambda probe has an aperture on the surface, through which exhaust gas enters. A porous layer adjoins the inlet aperture, said exhaust gas diffusing through said porous layer into a cavity. Said cavity is separated from the external exhaust gas by an oxygen-ion conductive electrolyte material. Electrodes, which are connected to plug contacts via cables, are situated on the outside of the electrolyte as well as on the side of the cavity. The electrolyte situated between them is denoted as a pump cell. In addition, a reference gas having a certain constant oxygen concentration is situated in the interior of the sensor element, separated from the cavity by the same electrolyte material. An additional electrode, which is also connected to a plug contact, is situated in contact with the reference gas. The electrolyte between said additional electrode and the cavity side electrode is denoted as the measurement cell.
According to the Nernst principle, an electric voltage is applied across the measurement cell, which is referred to below as measurement voltage and is determined by the concentration of oxidizing and reducing exhaust gas components in the cavity and in the reference gas. Because the concentration in the reference gas is known and invariable, the dependence on the concentration in the cavity is reduced.
In order to operate the lambda probe, said probe must be connected via the plug to an evaluation unit, which, e.g., is situated in an engine control device. The measurement voltage is detected by the electrodes and transmitted to the evaluation unit. A control circuit is located in the control unit, said control circuit maintaining the voltage across the measurement cell to a set point value by a so-called pump current being driven through the pump cell. Because the current flow in the electrolyte takes place by means of oxygen ions, the oxygen concentration in the cavity is influenced. In order to maintain the measurement voltage at a constant level during steady-state operation, exactly as much oxygen has to be pumped out of the cavity during operation with a lean air-fuel ratio (λ>1) as diffuses through the diffusion barrier. On the other hand, during operation with a rich air-fuel ratio (λ<1) so much oxygen has to be pumped into the cavity that the diffusing, reducing exhaust gas molecules are compensated. While taking into account the fact that the oxygen balance in the cavity is maintained at a constant level by the pump current controller, a linear connection between the diffusion current, and thereby the pump current, and the oxygen concentration in the exhaust gas results from the diffusion equation. The pump current is now measured in the evaluation unit and transmitted to the main computer of the engine control device. It follows from that which is stated above that the pump current represents a linear signal for the oxygen balance in the exhaust gas. The connection between the lambda value and the oxygen balance is in fact non-linear, as the following equation proves.
i ) C 02,Abgas =(1−1/λ) C 02,Air (2)
The curvature of the curve is however sufficiently small in the region which is relevant for the engine control in order to permit an exact determination of the lambda value from the pump current.
Broadband lambda probes are, for example, known from the German patent publication DE 10 2005 061890 A1 as well as from the German patent publication DE 10 2005 043414 A1, wherein the publication DE 10 2005 061890 A1 describes the design of a broadband lambda probe, in which provision is made according to the invention for the use of certain chemical elements during the construction thereof.
In internal combustion engines comprising two or more cylinders, which discharge the exhaust gas into a exhaust manifold, the pipes of which open into a common exhaust pipe, the lambda values of the individual cylinders can vary either due to different air charges caused, for example, by pressure surges in the intake manifold or due to different fuel quantities caused, for example, by tolerances of the injection valve or due to a combination of both causes. Such individual cylinder lambda fluctuations can adversely affect the performance of the engine as described below.
If, for example, a three-way catalytic converter is installed in the exhaust gas pipe and the exhaust gas from the individual cylinders is unevenly distributed across the cross section of the catalytic converter, a satisfactory conversion of the exhaust gas is not possible. In a catalyst segment which is exposed to lean exhaust gas, the oxidizing exhaust gas components cannot be converted; whereas in a catalyst segment which is exposed to a rich exhaust gas, the reducing exhaust gas components cannot be converted. In addition, the efficiency decreases and the fuel consumption thereby increases if a complete combustion of the fuel does not take place in a cylinder operated with a rich air-fuel ratio. Furthermore, incompletely combusted fuel from the cylinders operated with a rich air-fuel ratio and excess air from the cylinders operated with a lean air-fuel mixture can after-react in the exhaust pipe. Energy is thereby released which can lead to a thermal overstressing of and even to damage to the components installed in the exhaust gas system, in particular the catalytic converter.
It is therefore desirable in a closed control circuit to not only adjust the mean lambda value of all the cylinders to a set point value but also said mean lambda value of each individual cylinder. Such a method is denoted below as an individual cylinder lambda control. In addition, the American on-board diagnostics regulations (OBD) for the model year 2011 require a detection of individual cylinder lambda fluctuations, which is also referred to below as out-of-tune diagnostics or fuel trim diagnostics.
Single cylinder lambda controls are already known from prior art. Thus, the German patent publication DE 102 60 721 A1, for example, describes a method and a device for diagnosing the dynamic properties of a lambda probe, which is used at least temporarily for an individual cylinder lambda control. The method is thereby characterized in that at least one manipulated variable of the lambda control is measured and compared with a predefinable maximum threshold. In the event of the maximum threshold being exceeded, the dynamic behavior of the lambda probe is evaluated as being insufficient with regard to usability for the individual cylinder lambda control.
Prior art or respectively the subject matter of earlier patent applications uses the lambda signal of a two point lambda probe or a broadband lambda probe for an out-of-tune diagnostics or an individual cylinder lambda control. In so doing, a number of difficulties arise.
One difficulty is that the relevant frequencies of the lambda signal are damped. A significant damping is caused by the protective tube. This problem relates to both two point as well as broadband lambda probes. In the case of a broadband lambda probe, still further damping effects can in fact be added, namely as a result of the diffusion barrier and as a result of the pump current regulator depending on the design thereof. All of the damping effects act in a cumulative way. Frequencies in the actual lambda value created by individual cylinder fluctuations can be damped in a speed range around 2000 rpm by over 50% by means of the diffusion barrier. At higher rotational speeds, the damping continues to increase. The signal-to-noise ratio worsens which impairs the out-of-tune diagnosis as well as the individual cylinder lambda control. Viewed in terms of damping, a two point lambda probe can therefore have advantages with respect to a broadband lambda probe in the range around λ=1.
A broadband lambda probe has however also advantages with respect to a two point lambda probe. One advantage is that a lambda control with a broadband lambda probe can constantly adjust the mean lambda to a set point value. In contrast, the typical method used with a two point lambda probe, the so-called two point control, causes an oscillation in the lambda probe signal and thus adjusts only the mean value over time to the set point value. The individual cylinder lambda fluctuations are superimposed by the much stronger oscillations resulting from the control intervention such that the detection is impaired.
In addition, a method is known, in which an observer algorithm for the individual cylinder lambda values is supported by the measured value of a broadband lambda probe. Because the observer algorithm is based on the model of the system, which has the individual cylinder lambda values as input variables and the lambda mean value as output variable, said algorithm will be referred to below as the model supported method. An important parameter for the observer algorithm is the operating point dependent dead time of the lambda probe. The method is thereby impaired in that the dead time varies with production bandwidth and ageing. In order to resolve this difficulty, a dead time adaption method is described, which is however likewise afflicted with disadvantages. An active fuel adjustment is thereby required for the adaption. In addition, said adaption can only insufficiently depict a possible operating point dependency of the dead time variation.
SUMMARY OF THE INVENTION
It is therefore the aim of the invention to provide a method and a device, which in using properties of an exhaust gas probe ensure a single cylinder lambda control and an improved out-of-tune diagnosis.
The aim of the invention which relates to the method is thereby met by the fact that a pump voltage or a pump voltage change is determined via the pump cell in addition to the pump current and said value is transmitted to the diagnosis apparatus. The advantage thereby is that the pump cell of the exhaust gas probe, which is designed as a broadband lambda probe, is operated in principle like a two point lambda probe, and the disadvantages with regard to the previously described damping during use of the broadband lambda probes do not affect the method. The out-of-tune diagnosis as well as the single cylinder control can thereby be optimized.
It is particularly advantageous if the pump voltage or the pump voltage change is evaluated in the diagnosis apparatus in combination with a regular lambda signal of the exhaust gas probe, which is designed as a broadband lambda probe, as is described below.
If a mean lambda value of all the cylinders is uniformly adjusted or adjusted close to 1 using the regular lambda signal of the exhaust gas probe and the signal of the pump voltage is evaluated, small individual cylinder fluctuations in the pump voltage can also be detected, which can be used in performing the out-of-tune diagnosis and the single cylinder diagnosis. This is the case because just as was true for the two point lambda probe, the dependency of the pump voltage in this lambda range on small fluctuations is especially strong.
With regard to an improved out-of-tune diagnosis, provision is made in a variant to the method for a filter having band-pass or differential characteristics to be applied to the measured signal of the pump voltage. Interfering signals can thereby be extensively suppressed because only the frequency ranges for the pump voltage are taken into account, which have been activated as a result of the individual cylinder lambda fluctuation.
In this connection, it has been proven to be advantageous if the transmission behavior of the filter is specified as a function of the operating point and is manipulated particularly as a function of the rotational speed of the internal combustion engine. A transmission function adapted to the rotational speed facilitates a dynamic adaptation of the frequency range, in which the individual cylinder lambda fluctuations can occur with the pump voltage signal.
With regard to an additionally improved suppression of interfering signals, provision can further be made for a correction term to be subtracted from the value of the gradient of the filtered signal of the pump voltage, said correction term being assumed on a model basis for an error-free system and being likewise predefined as a function of the operating point. The difference is then temporally integrated.
If a certain threshold value for the temporal integral is exceeded, an out-of-tune error is diagnosed, which can be entered into an error memory of an overriding engine control or displayed as a warning message. A robust out-of-tune diagnosis with respect to the future American on board diagnostics legislation can then be implemented.
Provision is made in a likewise preferred variant to the method for the temporal signal of the pump voltage to be subjected to a frequency analysis and for an out-of-tune diagnosis or a cylinder balancing to be performed on the basis of these frequency components ascertained during the frequency analysis. To meet this end, the temporal signal of the pump voltage is subjected to a Fourier analysis, and the amount of a motor play frequency and if need be integer multiples of the same are determined.
If the dead time or other dynamic parameters of the exhaust gas probe are ascertained by comparing the signal for the pump voltage with the regular lambda signal of said exhaust gas probe, model parameters of a model-supported cylinder balancing control can thereby be adapted on the basis of the regular lambda signal of said exhaust gas probe. Ageing effects of the sensor element of said exhaust gas probe can, for example, be taken into account during the cylinder balancing control.
A preferred application of the previously described method provides for the use thereof in internal combustion engines having multi-bank exhaust systems, in which the cylinders are subdivided into several groups and the exhaust gas of the different cylinder groups is conveyed into separate exhaust gas ducts.
The aim relating to the device is thereby met in that the previously described method can be implemented in the diagnosis apparatus and especially the signals of the pump voltage applied across the pump cell of the exhaust gas probe cab be evaluated.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in detail below using the exemplary embodiments depicted in the figures. In the drawings:
FIG. 1 shows a schematic depiction of an internal combustion engine and
FIG. 2 a and FIG. 2 b show in a schematic depiction a broadband lambda probe as an exhaust gas probe at different exhaust gas compositions.
DETAILED DESCRIPTION
FIG. 1 shows a technical environment by way of example, in which the method according to the invention can be applied. An internal combustion engine 1 comprising an engine block 40 and an air intake duct 10 , which supplies the engine block 40 with combustion air, is depicted in the figure, wherein the air quantity in the air intake duct 10 can be determined with an air intake measuring device 20 . The exhaust gas of the internal combustion engine 1 is thereby led across an emission control system which comprises an exhaust gas duct 50 as the main component, in which a first exhaust gas probe 60 is disposed upstream of a catalytic converter 70 and if applicable a second exhaust gas probe 80 is disposed downstream of said catalytic converter 70 in the direction of flow of the exhaust gas.
The exhaust gas probes 60 , 80 are connected to a control unit 90 which calculates the mixture from data of said exhaust gas probes 60 , 80 and the data of the air intake measuring device 20 and actuates a fuel metering device 30 for metering fuel. Provision is made for a diagnosis apparatus 100 , with which the signals of the exhaust gas probes 60 , 80 can be evaluated, to be coupled with or integrated into the control unit 90 . The diagnosis apparatus 100 can additionally be connected to a display/memory unit, which is not depicted here. A lambda value, which is suitable for the emission control system to achieve an optimal purification effect, can be adjusted with the aid of said control unit 90 using the exhaust gas probe 60 disposed behind the engine block 40 . The second exhaust gas probe 80 disposed downstream of the catalytic converter 70 in the exhaust gas duct 50 can also be evaluated in the control unit 90 and serves to determine the oxygen storage capacity of the emission control system in a method according to prior art.
An internal combustion engine 1 is exemplarily shown, which comprises only one exhaust gas duct 50 . The inventive method however also applies to internal combustion engines 1 comprising multi-bank exhaust systems, in which the cylinders are subdivided into several groups and the exhaust gas of the different cylinder groups is conveyed into separate exhaust gas ducts 50 .
FIG. 2 a and FIG. 2 b show in schematic depiction an exhaust gas probe 60 , which, as is provided for by the inventive method, is embodied as a broadband lambda probe and is exposed on the one hand to a rich exhaust gas 110 ( FIG. 1 a ) and on the other hand to a lean exhaust gas 120 ( FIG. 1 b ).
An exhaust gas probe 60 , as said probe is, for example, described in the German patent publication DE 10 2005 061890 A1, comprises a pump cell having an outer electrode 62 and an inner electrode 67 as well as a measuring cell that includes a measuring electrode 68 and a reference electrode 69 . The measuring electrode 68 and the reference electrode 69 are short-circuited. The exhaust gas probe 60 is normally designed in planar technology from several solid electrolyte layers 61 . Provision is further made for a heating device, which is embedded in insulation and is used to heat the sensor element (not depicted in the figure). The exhaust gas 110 , 120 can be delivered to a measuring chamber 66 via an opening 64 in the form of a bore and through a diffusion barrier 65 . The inner electrode 67 of the pump cell as well as the measuring electrode 68 of the measuring cell is thereby disposed in the measuring chamber 66 . The outer electrode 62 on the exterior side of the exhaust gas probe 60 facing the exhaust gas 110 , 120 has a protective coating 63 . The reference electrode 69 is disposed in a reference air duct, which is filled with ambient air.
A potential difference, the so-called Nernst voltage 160 , is measured via the Nernst cell between the measuring electrode 68 and the reference electrode 69 . A voltage is applied to the pump cell from the outside. Said voltage produces a current referred to as pump current 150 , with which—as a function of polarity—oxygen ions are transported.
An electronic control circuit ensures that the pump cell always exactly delivers as much oxygen in the form of O 2 ions to the measuring chamber or conveys away as much oxygen in the form of O 2 ions from said measuring chamber 66 in order that a lambda value of λ=1 occurs, wherein oxygen is pumped out in the case of appliance lean exhaust gas 120 (excess air) and on the other hand oxygen is delivered in the case of appliance rich exhaust gas 110 . The pump current 150 adjusted by the control circuit is dependent on the air ratio lambda in the exhaust gas and forms the output signal of the broadband lambda probe. In the case of lean exhaust gas 120 , in which O 2 and also NO are present as the main components, the pump current 150 is positive and is negative in the case of rich exhaust gas 110 comprising CO, H 2 and HC (hydrocarbons).
In the case of an exhaust gas probe 60 designed as a broadband lambda probe, provision is made according to the invention for a pump voltage, which is applied across the pump cell, i.e. between the outer electrode 62 and the inner electrode 67 , to be measured, to be transmitted to the control unit 90 and if applicable to be used in combination with the regular lambda signal, which is derived from the pump current 150 , for the out-of-tune diagnosis or respectively for the single cylinder control.
The pump cell functions in this case like a two point lambda probe. One side is exposed to the exhaust gas 110 , 120 and the other side to a reference gas, the composition of which is in fact not constant, said reference gas having however a constant Nernst potential. It is thus irrelevant that the constant Nernst potential is only set by means of the pump current 150 . It must however be taken into account that in contrast to a two point lambda probe, a current flows through the pump cell. For that reason, the voltage across the pump cell does not correspond to the aforementioned Nernst equation (1) which describes a currentless electrolyte. On the contrary, a pump current regulator has to set a voltage in order to drive the pump current 150 , said voltage being different from the aforementioned equation (1). The difference results from the pump current 150 and the internal resistance of the pump cell. Under the simplified assumption that no oxidizing or reducing exhaust gas components are present besides oxygen, the pump voltage is described by the following equation.
a ) U p =U Abgas −U Hohlraum =( R*T /4 *F )*ln( p O2,Abgas /p O2,Hohlraum )+ R p *I p (3)
(a) Abgas=Exhaust Gas, Hohlraum=Cavity
In this equation U Abgas stands for the electrical potential on the exhaust gas side, U Hohlraum for the constantly maintained electrical potential on the cavity side or respectively in the measuring chamber 66 , p O2,Hohlraum and p O2,Abgas for the oxygen partial pressure in the measuring chamber 66 or in the exhaust gas 110 , 120 . R p stands for the internal resistance of the pump cell, I p for the pump current 150 as well as T for the temperature, R for the general gas constant and F for the Faraday constant.
The electrical pump current direction is from the exhaust gas side to the cavity side. The oxygen ion current is thereby opposite to the electrical current direction as a result of the oxygen ions being negatively charged. Because even more oxygen ions have to be pumped, the richer the exhaust gas is, the pump current I p 150 increases with the oxygen concentration of the exhaust gas or respectively with the oxygen partial pressure p O2,Abgas .
Provision is made in a further embodiment variant of the method with regard to an out-of-tune diagnosis in a single cylinder lambda control for a filter D having band-pass or differential characteristics to be applied to the measured pump voltage U p (t), said filter D allowing only frequencies of U p (t) to pass through which are activated by individual cylinder fluctuations. The transmission behavior of D can be a function of the operating point and can especially be dependent on the rotational speed of the internal combustion engine 1 . A correction term is subtracted from the value of the gradient, said correction term corresponding to the gradient which is assumed as possible for an error-free system. K can likewise be a function of the operating point. In order to simplify the notations, the dependencies of D and K are however not explicitly presented below. For an error-free system, the difference between D(U p (t)) and K would have to always be negative. Nevertheless, short-term interferences, which are not attributed to individual cylinder lambda fluctuations, can make said difference temporarily positive.
In order to achieve a robust out-of-tune diagnosis, an integral is formed from the difference between D(U p (t)) and K having a lower limit of zero. This integral is to be denoted as W and is the diagnostic value of the out-of-tune diagnosis. The law of formation for W reads:
W (0)=0 (4a)
and
W ( t +) t )=max{0 ,W ( t )+) t *(* D ( U p(t) )*− K )} (4b)
An out-of-tune error is diagnosed if W exceeds a certain threshold value.
Using the previously described variations of the method, deviations in the single cylinder lambda control can be better diagnosed without additional material expense, which is particularly advantageous with regard to stricter legislative regulations with regard to on board diagnostics. | The invention relates to a method and device for diagnosing deviations in a single cylinder lambda control in an internal combustion engine having at least two cylinders and an exhaust gas sensor designed as a broadband lambda sensor, wherein a pump current is evaluated by means of a pump cell and the pump current is used at least temporarily for an individual cylinder lambda control. According to the invention, a pump voltage or a pump voltage change is determined via the pump cell in addition to the pump current and the value is transmitted to a diagnosis apparatus. Deviations in the single cylinder lambda control can thus be better diagnosed without additional material expense according to the invention, which provides advantages in particular in respect of tightened rulemaking in on-board diagnosis. A preferred application of the method is the use in internal combustion engines having multi-bank exhaust systems. | 5 |
[0001] This application claims the benefit of priority to U.S. provisional patent application Ser. No. 60/582,539, filed Jun. 25, 2004.
BACKGROUND OF INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates generally to integral polymer geogrids and other oriented grids used for structural or construction reinforcement purposes. More particularly, the present invention relates to such integral polymer grids made from homopolymer and copolymer polypropylene in which a beta nucleation agent has been added to enhance the desired physical characteristics of the grid.
[0004] This invention also relates to the method for the production of such beta nucleated polypropylene grids so as to improve production rates and parameters for the orientation of the polymer grids. Lastly, the present invention relates to the use of such integral polymer geogrids for soil reinforcement and methods of such reinforcement.
[0005] For the purpose of this invention, the term “integral polypropylene grids” is intended to include integral polypropylene geogrids and other integral polypropylene grid structures made by orientating (stretching) starting materials in the form of sheets or the like that have a mean thickness of at least 0.75 mm, and preferably at least 1.5 mm or more.
[0006] 2. Description of the Related Art
[0007] Plastic material integral grid structures having mesh openings defined by a generally rectangular grid of substantially parallel, orientated strands and junctions therebetween, such as geogrids, have been manufactured for over 25 years. Such grids are manufactured by extruding an integrally cast sheet which is subjected to a defined pattern of holes or depressions followed by the controlled uniaxial and biaxial orientation of the holes or depressions to form into mesh openings. These integral oriented polymer grid structures can be used for retaining or stabilizing particulate material of any suitable form, such as soil, earth, sand, clay, gravel, etc. and in any suitable location, such as on the side of a road or other cutting or embankment, beneath a road surface, runway surface, etc.
[0008] The manufacture and use of such geogrid and other integral polymer grid structures can be accomplished by well known techniques. As described in detail in U.S. Pat. Nos. 4,374,798 to Mercer et al., 5,419,659 to Mercer et al., 4,590,029 to Mercer et al., 4,743,486 to Mercer and Martin, and 4,756,946 to Mercer, a starting polymer sheet material is first extruded and then punched to form the requisite defined pattern of holes or depressions. In U.S. Pat. Nos. 3,252,181, 3,317,951, 3,496,965, 4,470,942, 4,808,358 and 5,053,264, the starting material with the requisite pattern of holes or depressions is formed in conjunction with the polymer extrusion. It is intended that the present invention be applicable to all integral polypropylene grids regardless of the method of forming the starting material or orienting the starting material into the geogrid or grid structure. The subject matter of the foregoing patents is expressly incorporated into this specification by reference as if the patents were set forth herein in their entireties. These patents are cited as illustrative, and are not considered to be inclusive, or to exclude other techniques known in the art for the production of integral polymer grid materials.
[0009] The polymeric materials used in the production of such integral grids heretofore have been high molecular weight homopolymer and copolymer polypropylene and high density, high molecular weight polyethylene copolymer and with the addition of varying amounts of additives, such as carbon black, ultra-violet light inhibitors, etc. For the use and applications of integral polymer geogrids and other integral polymer grid structures, such as described in the above-referenced U.S. Pat. No. 5,419,659 to Mercer et al., it would be desirable and advantageous, and significantly more economically viable, if it were possible to enhance the break and yield tensile strengths, the torsional and flexural stiffness, the modulus characteristics, and the impact strength of the oriented grids. It would also be desirable and more economic if the speed of orientation, whether uniaxial or biaxial, from the integrally cast and perforated starting material could be increased significantly above the orientation speeds currently being practiced.
SUMMARY OF THE INVENTION
[0010] The most common crystal form of polypropylene is the alpha crystal which melts at approximately 160° C. for typical Zeigler-Natta polymerized homopolymer or copolymer polypropylene. A less common form, known as the beta or hexagonal crystal form, generally comprises less than 5% of the polypropylene crystals. The beta crystals have a melting point that is typically 12-15° C. below that of the alpha form. It is known that the beta phase of an isotactic polypropylene can improve toughness and impact strengths. Finally, a beta nucleator activated at the appropriate processing temperature during cast sheet extrusion, sharply raises the percentage of beta crystals.
[0011] There are known different beta initiators for polypropylene. The most common types known are red dye pigments (e.g. quinacridones). Others are considered non-pigmenting such as a new class developed as a solid white powder by New Japan Chemical designated NJ Star NU-100, which is introduced into polypropylene during processing or compounding. Previously, beta nucleants have been added for processing biaxially oriented polypropylene film (BOPP). This work with BOPP film is disclosed in U.S. Pat. Nos. 5,310,584, 5,594,070, 5,317,035, 5,236,963, 5,176,953, and 4,975,469.
[0012] It has now been surprisingly found that compounding polypropylene with a beta nucleating agent which converts the alpha polypropylene to the beta form, preferably to a level up to 80%, for the polypropylene in the starting sheet material, will result in a final oriented grid, stretched either uniaxially or biaxially, which has significantly higher yield and break tensile strengths, torsional and flexural stiffness, modulus characteristics, and impact resistance, over substantially identical oriented grids made from polypropylene without a beta nucleating agent added. The increased strengths and stiffness are beyond those that have been obtained to date in the practice of the referenced patents at all the indicated starting sheet thicknesses. Another way to view the present invention is that the heretofore obtainable finished product yield and break tensile strengths; as well as the 2% and 5% tensile strengths, modulus, torsional and flexural stiffness and impact characteristics, at all previous starting sheet thicknesses as practiced in the referenced patents, can now be obtained with starting sheet thicknesses and masses that are 5%-25% less than those prior to the practice of the present invention.
[0013] It has further been surprisingly found that the speed of orientation of the beta-enhanced polypropylene starting material can be significantly increased and carried out at the same and lower temperatures over standard polypropylene starting materials, thus significantly reducing the production costs for manufacturing the final grids. This increase in speed has been demonstrated to be at least 1.5 times as high as currently practiced, and up to three times as high, or more. Finally, the oriented beta-enhanced polypropylene grids have a significantly lighter weight (lbs/sq.ft.) than conventional oriented polypropylene grids of the same strength and performance characteristics, thus saving on material and shipping costs.
[0014] It is believed that conversion of the alpha polypropylene crystals by the beta nucleating agent to as little as 20%-30% of the beta crystalline form in the final starting sheet material can cause the resultant oriented grid, after stretching uniaxially or biaxially, to exhibit the improved property characteristics and orienting enhancements described herein. However, higher conversion is clearly desirable so that the full benefits of the polypropylene beta crystalline structure result. Hence, the beta nucleating conversion should preferably result in a starting sheet material having up to 80%, or more, polypropylene in the beta crystalline form.
[0015] Accordingly, it is an object of the present invention to produce an integral geogrid or other grid structure from a beta nucleated polypropylene starting material according to known process methods, such as those described in the aforementioned U.S. Pat. Nos. 4,374,798, 5,419,659, 4,590,029, 4,743,486, 4,756,946, 3,252,181, 3,317,951, 3,496,965, 4,470,942, 4,808,358 and 5,053,264, as well as many other patents.
[0016] It is a further object of the present invention to produce a beta nucleated polypropylene geogrid or other grid structure manufactured in accordance with known process methods which will exhibit increased yield and break tensile strengths, increased 2% and 5% tensile strengths, increased modulus characteristics, increased torsional and flexural stiffness, increased impact strength and increased grid junction strengths as measured by current test methods, ASTM D6637 and the U.S. Army Corps of Engineers Methodology for the torsional stiffness.
[0017] Another object of the present invention is to provide a polypropylene starting material having at least 20%-30% of the polypropylene crystals in the beta form, preferably up to about 80%, which substantially increases the speed of orienting the perforated starting sheet at all defined starting sheet thicknesses, beyond those obtainable with presently used polypropylene starting materials.
[0018] Yet another object of the present invention is to produce an integral polypropylene geogrid or other grid structure by incorporating an additive that modifies the crystalline structure of the polypropylene cast starting sheet such that a broader window of processing in the form of lower orientation temperatures is realized, along with resultant increased yield and break tensile strengths, increased 2% and 5% tensile strengths, increased modulus characteristics, and increased torsional and flexural stiffness at all defined cast sheet thicknesses, over that achievable using identical polypropylene polymers without the additive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a table setting forth key properties for four finished integral geogrid products comparing a standard BX1200 polypropylene geogrid manufactured and sold by The Tensar Corporation, Inc. (Georgia) (hereinafter “Tensar”), the assignee of the instant application, at its manufacturing facilities in Morrow, Ga., with three test polypropylene integral geogrids manufactured by Tensar in the same way but containing a polypropylene beta nucleating agent in the starting sheet, but having different starting sheet thicknesses.
[0020] FIG. 2 is a continuation of Table 1 setting forth further properties of the finished geogrids listed in FIG. 1 .
[0021] FIG. 3 is a table which sets forth key properties for four finished integral geogrid products comparing Tensar's standard BX1200 polypropylene geogrid, also manufactured at Tensar's manufacturing facilities in Morrow, Ga., with three test polypropylene integral geogrids manufactured by Tensar in the same way but containing a second polypropylene beta nucleating agent in the starting sheet, and having different starting sheet thicknesses.
[0022] FIG. 4 is a continuation of Table 3 setting forth further properties of the finished geogrids listed in FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention contemplates the addition of one or more beta nucleation additives to the polypropylene batch for the extrusion of starting cast sheet. After or during extrusion, the beta nucleated sheet is perforated or depressed to form holes or indentations, and then either uniaxially or biaxially stretched in accordance with known methods and practices, preferably those described in the above-referenced U.S. Pat. Nos. 4,374,798, 5,419,659, 4,590,029, 4,743,486, and 4,756,946.
[0024] For the present invention, the more common red quinacridone dye nucleating agent is preferably used. The quinacridone dye is often effective at very low levels in the parts per million (ppm) range, and is generally formulated as a polymer concentrate having 2000 ppm, more or less, of the quinacridone dye in a polypropylene carrier.
[0025] One supplier of red quinacridone dye nucleating concentrate is Standridge Color Corporation (“Standridge”), of Social Circle, Ga. The Standridge beta nucleating concentrate is a concentrated pellet product that contains approximately 2000 ppm of the beta nucleating red quinacridone dye in a polypropylene homopolymer carrier resin. Another supplier of a red quinacridone dye nucleating concentrate is Mayzo, Inc (“Mayzo”) of Norcross, Ga. A Mayzo beta nucleating concentrate designated BNX BETA PP is a concentrated pellet product that is believed to contain 450 ppm, more or less, of the beta nucleating red quinacridone dye in a polypropylene homopolymer carrier resin that has a melt flow index of 4.0 grams/10 mins, more or less. Other manufacturers or suppliers may also provide an equivalent or similar beta nucleating agent when added to polypropylene resin. Another such product, for example, is designated NJ Star NU-100, and manufactured by a company named Japan Chemical Company. This beta nucleating agent is a solid white powder, and is introduced into polypropylene during processing or compounding.
[0026] The beta nucleating agent in concentrated pellet form is preferably blended with the polypropylene used to manufacture the grid prior to or during the extrusion of the starting cast sheet material. The beta nucleating concentrate is mixed with the polypropylene at levels of about 0.5% up to about 5% or more. With a concentrate containing 2000 ppm of the beta nucleating reagent, the preferred concentration of the beta nucleating reagent in the extruded or cast polypropylene starting sheet is about 10 ppm, and perhaps less, to about 100 ppm. The addition of the beta nucleating concentrate converts the normally alpha crystalline structure, with only about 5% beta crystals, or less, to a cast sheet after extrusion having up to 80% of the polypropylene in the beta crystalline form. It is this beta crystalline formation in the extruded or cast starting sheet material that, once uniaxially or biaxially oriented into a finished grid mesh, results in the higher yield and break tensile strengths, 2% and 5% tensile strengths, modulus characteristics, torsional and flexural stiffness, and impact strength. It is believed that the conversion of the alpha polypropylene crystals should produce at least fifty percent (50%) beta crystals, and preferably about 75% to about 80%, or more, in the polypropylene starting sheet in order to achieve the surprisingly improved results described herein.
[0027] The starting sheet thickness ranges and the extent and method of orientation are preferably the same as that disclosed in U.S. Pat. No. 5,419,659, for both uniaxial and biaxial orientation. The starting material, when biaxially stretched in accordance with one embodiment of the present invention, produces junctions between the strands which are not flat, but exhibit some thinning. The junctions have a minimum thickness which is not less than 75% of the thickness of the mid-point of any of the strands passing into the junction. Each junction is a solid junction and has a central zone which is thicker than the orientated lateral zones around the central zone.
[0028] Following the formation of the polypropylene starting material with the beta nucleator concentrate additive, and the subsequent uniaxial or biaxial orientation, the ratio of the center portion of any strand entering the junction and the thickest part of the resultant junction node is preferably about 90% or less, although this ratio could be larger or smaller than 90%, and not be outside the scope of the invention. This ratio on a conventional polypropylene biaxial grid (without a beta nucleating additive), made by Tensar, is approximately 78% or less. A beta nucleated starting sheet, when biaxially stretched, can orient more through the junction zone than does that of a non-beta nucleated sheet. It is believed that this increased junction orientation is one of the contributing factors to the increased tensile strengths and torsional or rotational stiffness of the beta nucleated grids. Conversely, a beta nucleated starting sheet, when biaxially stretched, can also orient more in the strand zones and less through the junction zone than that of a non-beta nucleated sheet, still providing increased tensile strengths and flexural stiffness of the beta nucleated grids.
[0029] With the addition of the beta nucleating agent in the starting sheet, and by following the standard extrusion temperature profile and extrusion throughput rates as practiced by Tensar for the range of uniaxial and biaxial polypropylene products offered for sale by Tensar, the starting cast sheet in accordance with the present invention should contain a high level of the beta form of crystallinity, at least 50%, and preferably from about 75% to about 80%, or more. It is believed that this unique crystal morphology changes the processing characteristics of the starting sheet during the subsequent uniaxial and biaxial orientation steps. These changes result in the sheet having a broader processing window, and an improved ability to draw the sheet at lower temperatures and higher speeds.
[0030] Initial trial work in accordance with the present invention was carried out by Tensar using a beta crystalline polypropylene coded B022SP, a 2.0 melt flow homopolymer polypropylene obtained from Sunoco Polymers of 550 Technology Drive, Pittsburgh, Pa. 15219. Standard flat “dog-bone”-shaped samples, having a thickness of about 0.060 inches, were prepared of the Sunoco beta crystalline polypropylene and conventional polypropylene, and the samples stretched in a lab stretcher in accordance with standard stretching protocols used by The Tensar Corporation. The samples were stretched at 4:1 and 5:1 ratios, all at 230° F. The middle six inches of oriented material (there being unoriented material in or near the clamped ends of each specimen), was tensile tested at an elongation rate of 5 mm./min. The 4:1 ratios showed an increase of 17% in tensile modulus, and an increase of 33% in ultimate tensile load for the Sunoco beta crystalline polypropylene samples over the conventional polypropylene samples. The 5:1 ratios showed an increase of 12% in tensile modulus, and 30% in ultimate tensile load.
[0031] Subsequent sheet plaques were prepared by Sunoco of its beta crystalline polypropylene and conventional polypropylene. The plaques having a thickness of about 0.060 inches were perforated and uniaxially oriented by Tensar on a laboratory stretcher in accordance with Tensar's standard testing protocol for stretching uniaxially oriented grid structures. The oriented beta nucleated samples showed a 77% increase in tensile modulus, and a 19%-33% increase in ultimate tensile strength over the oriented non-beta nucleated samples.
[0032] Later tests have demonstrated that a beta crystalline starting sheet made in accordance with the present invention orients more easily and requires less initiation stress to start the orientation than does a conventional polypropylene starting sheet without a beta nucleating additive. It is believed that these characteristics result in the higher stretching speeds. By way of example, Tensar demonstrated during trials, that with the addition of about 2.5% of the Mayzo concentrate (which is believed to contain 450± ppm red quinacridone dye beta nucleant) to the polypropylene resin, the resultant biaxial polypropylene grid can be oriented at two times the speed of the identical starting sheet without the beta nucleant addition. The identical process extrusion and stretching conditions were used for both starting sheets in these trials. Subsequent research indicates that this stretching speed could be increased to three times, or even higher, with the beta nucleant addition. The impact on improved productivity and lower production costs achieved by this invention should, therefore, be obvious.
[0033] A further benefit of the beta nucleation is a reduction in the basis weight of the final grid product without a loss in physical test properties relative to that of the current commercial products as produced by Tensar. It is currently believed that this weight reduction is achieved by the beta crystalline phase which causes microvoids or minute pores to form in the starting sheet when the sheet is oriented under the controlled conditions as practiced currently by Tensar for the family of uniaxial and biaxial products. These microvoids presumably lead to a density reduction as well as contributing to the increased orientation speeds via reduced initiation stress required for orientation.
Example 1
[0034] In a first example, a standard commercial Tensar polypropylene product, designated as BX1200, was used for comparison. Tensar BX1200 is a biaxially stretched and oriented integral geogrid produced from high molecular weight, fractional melt index polypropylene from a starting cast sheet having a thickness of 4.6 mm. Carbon black at approximately 1% is added to the final product for ultra-violet ray protection. The standard minimum average roll values (MARY) for the key properties of the Tensar BX1200 finished grid are shown in line (1) of Table 1 in FIG. 1 . For comparison, starting sheets having thicknesses of 4.60 mm, 4.15 mm, and 3.90 mm were prepared with an addition of about 2.68% of Mayzo beta nucleant BNX BETA PP concentrate added to the polypropylene. It is believed that this addition resulted in a polypropylene having a red quinacridone dye beta nucleant concentration of about 12 ppm. The beta nucleated starting sheets were prepared and stretched in accordance with the same process conditions as the commercial Tensar BX1200 product, including the about 1% carbon black addition. The same material properties were measured and are listed in lines (2), (3) and (4) of Table 1 in FIG. 1 .
[0035] As shown in Table 1 in FIG. 1 , each cast sheet thickness with the beta nucleant added, exceeded all of the key desired properties of the standard Tensar BX1200. Of special significance is that the 3.90 mm thick cast starting sheet with the beta nucleant added, line (4) of Table 1, which is almost 18% thinner than the standard Tensar BX1200 starting sheet, produced a grid which exceeded all of the property requirements for the standard Tensar BX1200 grid. Without the beta nucleant addition, a 3.90 mm thick polypropylene starting sheet would have produced a grid with properties far short of these properties. These results confirm that a minimum of 10%, more or less, weight (thickness) reduction in the starting sheet material with the addition of a beta nucleant, will achieve the same or better grid properties following orientation than a sheet without addition of the beta nucleant.
[0036] Sheet dimensions of the products of Example 1 are shown in the continuation of Table 1 in FIG. 2 . Measurements of aperture length, aperture area, strand thickness and width, strand cross-sectional area, node width and thickness of the BX1200 finished grid are there compared to the three beta nucleated test sheets having thicknesses of 4.60 mm, 4.15 mm, and 3.90 mm. The results show that the addition of the beta nucleant caused the grid aperture lengths and open areas to be smaller, while resulting in wider strands and nodes and comparable greater strand cross-sectional area. In each beta nucleated test grid, the junction (or node) tensile strength was 95%, or higher, of the tensile strength of the strands.
Example 2
[0037] As in the first example, the standard commercial Tensar BX1200 polypropylene biaxial geogrid was used for comparison. The standard minimum average roll values (MARV) for the key properties of the Tensar BX1200 finished grid are also shown in line (1) of Table 2 in FIG. 3 . For comparison, three test starting sheets having thicknesses of 4.60 mm, 4.35 mm, and 4.00 mm, respectively, were prepared with an addition of either 1.5% or 1.65% of the Standridge beta nucleant polypropylene concentrate added to the polypropylene starting sheets. The Standridge beta nucleant polypropylene concentrate used in this example was a quinacridone red dye concentrate with a polypropylene carrier resin having approximately 2000 ppm of the red dye beta nucleant. Hence, the concentration of the beta nucleant in the 4.60 mm and 4.35 mm test samples, lines (2) and (3) of Table 2 in FIG. 2 was approximately 30 ppm (a 1.5% addition), and the concentration in the 4.0 mm was about 33 ppm (a 1.65% addition). The beta nucleated starting sheets were prepared and stretched in accordance with the same process conditions as the commercial Tensar BX1200 biaxial geogrid. The same material properties were measured and are shown in lines (2), (3) and (4) of Table 2 in FIG. 3 .
[0038] Table 2 of FIG. 3 shows that the cast sheet thicknesses of 4.6 mm and 4.35 mm with the Standridge beta nucleant added, lines (2) and (3), also exceeded all of the key desired properties of the standard Tensar BX1200 biaxial geogrid. The 4.0 mm sheet, line (4), had properties which were only slightly less than the BX1200 control grid in most categories, and was still superior in torsional and flexural strength.
[0039] Sheet dimensions of the products of Example 2 are shown in the continuation of Table 2 in FIG. 4 . The results show that the addition of the Standridge beta nucleant allowed the aperture lengths and areas of the grid to be larger than the BX1200 control grid. The resulting strand widths of the beta nucleant treated polypropylene grids were narrower with narrower node widths but having larger node thicknesses. In each beta nucleated test grid, the junction (or node) tensile strength was 95%, or higher, of the tensile strength of the strands.
[0040] With the Standridge beta nucleant, the node mass is not pulled into the MD and CMD strands as much as with the Mayzo nucleant, resulting in thicker nodes, narrower strands, higher flexural rigidity, but lower torsional rigidity for the Standridge nucleated geogrid product, even though comfortably within current specifications for the BX1200 geogrid. Also, the aperture area is larger with the Standridge additive.
[0041] It is noted that when using the nucleating agents, the torsional stiffness increased even at the thinnest starting sheet. Application research strongly indicates that torsional resistance effectively captures the complex interaction of initial tensile modulus, stiffness, confinement, and stability when used in soil stabilization. Hence, geogrids and other grid structures made in accordance with the present invention, having this increased torsional stiffness resulting from the beta nucleant additive, should perform even better and should be more economically viable when used in soil stabilization applications. | Integral polymer grids, such as geogrids, are made by stretching and orienting a polypropylene starting sheet material having a defined pattern of holes or depressions in which the polypropylene is at least 50%, and preferably up to about 80%, beta crystals caused by adding a beta nucleating agent to the polypropylene, preferably in concentrations between about 10 ppm to about 100 ppm. Such beta nucleated polypropylene grids exhibit increased yield and break tensile strengths, increased 2% and 5% tensile strengths, increased modulus characteristics, increased torsional stiffness, increased impact strength, and increased grid junction strength. Methods for manufacturing the beta nucleated polypropylene mesh grids are disclosed, along with applications for stabilizing particulate material in civil engineering structures, and the like. | 2 |
RELATED APPLICATION
This application claims priority of U.S. Patent Application Ser. No. 61/681,888, entitled METHOD FOR THE TREATMENT OF ACNE, filed Aug. 10, 2012, the entire disclosure of which is hereby incorporated by reference as if being set forth in its entirety herein.
FIELD OF THE INVENTION
This application related to methods for the treatment of acne vulgaris, commonly referred to simply as “acne.”
BACKGROUND OF THE INVENTION
Acne is a commonly occurring skin disorder. It is characterized by an inflammation of the pilosebaceous unit, including the sebaceous gland. Acne lesions can take the form of comedones, papules, pustules, or nodules. Acne lesions typically appear on the face, but also occur on the back, chest and shoulders. Acne lesions are associated with Propionibacterium acnes ( P. acnes ). Growth of P. acnes is thought to be associated with, if not the cause of, the inflammatory component of acne.
The severity of acne varies widely from individual to individual, and also varies over time for any given individual. Even mild cases of acne can be cosmetically unappealing and at times disfiguring. Occasionally, acne lesions heal but leave permanent scars which are themselves sometimes prominent and permanently disfiguring.
There are a variety of treatments available for acne. Oral antibiotics (e.g. minocycline) may be used to reduce the population of P. acnes . Other oral antibiotics, such as doxycycline, have been used to treat acne when used at concentrations too low to have an antibiotic affect on P. acnes , but high enough to exert an anti-inflammatory action on the acne lesions. Topical retinoids, such as tretinoin, and topical antibiotics, such as clindamycin or azelaic acid, have also been used. In female patients, oral contraceptives have been observed to have an anti-acne effect, and are sometimes prescribed for that purpose. Orally administered isotretinoin is highly effective, but is known to produce a wide array of side effects, including sometimes severe psychiatric effects. Exposure to light, whether in the form of sunlight, or specific wavelengths of light, has also been shown to have a beneficial effect in the treatment of acne.
None of these treatments are compellingly effective, some have undesirable side effects, and all are subject to diminished effectiveness due to poor patient compliance —a common occurrence in the affected age group.
Photodynamic therapy (PDT) is an established therapeutic method for certain disorders. PDT is characterized by the use of (1) a phototherapeutic agent and (2) light. The phototherapeutic agent is applied or provided to the tissue or organ of interest. The light is used to cause a reaction (such as photoexcitation) in either the phototherapeutic agent, or in a metabolite of the phototherapeutic agent, or in a compound produced in response to the presence of the phototherapeutic agent (the activation reaction). This reaction results in a therapeutic effect.
Early phototherapeutic agents included porphyrins such as hematoporphyrin IX, hematoporphyrin derivative, or other such molecules, including Photofrin II.
The pioneering work of Kennedy & Pottier resulted in the discovery of the use of aminolevulinic acid (ALA) as a phototherapeutic agent. ALA is a precursor to a naturally occurring molecule—protoporphyrin IX. Exposing skin to light activates protoporphyrin IX in the skin. That is, the light excites or causes a reaction in the protoporphyrin IX molecule that results in the formation of reactive free radicals. Naturally occurring protoporphyrin IX can be activated by exposure to light, but occurs in quantities too small to cause any serious effect in normal tissue. By administering exogenous ALA, cells and tissues can be caused to produce greatly increased amounts of protoporphyrin IX. The resulting high concentrations of protoporphyrin IX can result in the generation of fatal quantifies of free radicals in the target cells/tissue when protoporphyrin IX is activated by exposure to light.
Kennedy & Pottier found that ALA-induced production of protoporphyrin IX made it possible to use PDT in the treatment of several disorders of metabolically active tissues. This technology has been used in the successful commercial product Levulan®, produced by Dusa Pharmaceuticals, and which has been approved by the U.S. FDA for the treatment of actinic keratoses.
Kennedy and his co-workers believed that ALA-based PDT could be used to treat acne, although they did not report any clinical resolution of acne by this method. See, U.S. Pat. No. 5,955,490. Also, they reported that the ability of light to excite protoporphyrin IX in acne lesions disappeared within 24 hours.
Kennedy reported that the ability of light to excite protoporphyrin IX in skin having acne lesions could persist to 24 hours if an occlusive covering was placed over the skin, but found that when this was done the surrounding healthy skin had as much free-radical generating protoporphyrin IX as did the acne lesions. As Kennedy contemporaneously reported, a phototherapeutic agent must have “a high degree of specificity” for the target tissue. Kennedy, J. C. “ Phtochemotherapy - Clinical Aspects ” NATO ASI Series, Springer-Verlag at p. 462 (1988). Kennedy's observation of the presence of equal amounts of protoporphyrin IX in acne lesions and in surrounding normal tissue is not specific at all.
Other workers in this field persisted in attempts to employ ALA-based PDT in the treatment of acne. See, U.S. Pat. No. 6,897,238 to Anderson. Anderson used ALA based PDT to treat acne in a small group of patients and taught that light must be applied to the skin within 1 to 12 hours after application of ALA to the skin containing acne lesions, preferably about three hours after application of the ALA.
Anderson's use of a 1 to 12 hour, and preferably a 3 hour waiting period between ALA application and exposure to light was consistent with what was by then the generally accepted timeline of ALA metabolism and protoporphyrin IX production. Research by Kennedy & Pottier showed that ALA was metabolized in mouse skin to result in peak protoporphyrin IX concentration in about six hours, with protoporphyrin levels returning to near pretreatment baseline in about 18 hours. Pottier et al, Photochemistry and Photobiology , Vol. 44, No. 5, pp. 679-87 (1986).
These anecdotal reports of the use of ALA-based PDT to treat acne were eventually followed by a full scale clinical trial on a group of patients large enough to provide statistically meaningful comparisons between the effectiveness of ALA-based PDT on one hand, and exposure to light alone on the other. The result of this clinical trial is available at www.clinicaltrials.gov, NCT 00706433. In this study ALA was applied to skin presenting acne lesions 45 minutes before exposure to activating light. This clinical trial determined that the use of ALA-based PDT produced results that were statistically indistinguishable from the use of light alone. That is, the ALA-based PDT had no effect.
An eight week study compared the effectiveness of ALA-based PDT with exposure to light alone as a treatment for acne. This study also compared delays of 15, 60 and 120 minutes between application of ALA and the exposure to photoactivating light. Among patients where the delay was either 15 or 120 minutes, there was no difference in the results obtained using ALA-based PDT or using light alone. For the 60 minute patients, light alone produced slightly better results than treatment with ALA-based PDT.
Thus, ALA-based PDT has not been an effective treatment for acne.
There exists a need to find a more effective way to utilize ALA-based PDT in the treatment of acne.
SUMMARY OF THE INVENTION
The inventors have discovered that in order for ALA-based PDT to be successfully used in the treatment of acne, the application of light after the application of ALA to the skin should be delayed by at least 12 hours, and possibly as long as 36 hours. An interval of 24 hours between application of ALA to the skin and exposure to light can result in optimal anti-acne therapy.
DETAILED DESCRIPTION OF THE INVENTION
In the method of this invention, ALA-based PDT is used to treat acne by applying an ALA compound to skin having acne lesions, and then waiting at least 12 hours before applying light to the skin to activate the resulting protoporphyrin IX. By that time, the ALA-induced protoporphyrin IX has not only persisted in the skin, but has localized in effective concentrations in the pilosebacious unit.
The data below shows that the ALA-based PDT method of this invention provides an effective treatment for acne. Contrary to the experience of the prior art in using various ALA-based PDT methods to treat acne, the method of this invention is effective, and, to a much greater degree, has the required specificity for acne lesions. This remarkably different and highly desirable result is obtained by departing from the conventional belief that ALA-induced protoporphyrin IX is largely dissipated within 12 hours.
The post-application waiting period before light exposure should be from about 12 to 48 hours, although waiting periods of 12 to 36 hours, 18 to 36 hours, 18 to 24 hours or 24 to 36 hours are preferred.
Derivatives of ALA, including alkylated derivatives of ALA, can also be used. These include C 1 to C 8 alkyl derivatives of ALA such as methyl ALA and hexyl ALA.
Topical formulations suitable for use in ALA-based PDT are well known in the art. These include ALA and its pharmaceutically acceptable salts, such as ALA hydrochloride and sodium ALA. Any topical vehicle that delivers ALA to the skin so that it can be taken up by the acne lesions can be used. Levulan® ALA is a formulation that is commercially available and suited to use in this invention.
The concentration of ALA in the topical formulation can range from 1 to 30 percent. Concentrations within this range can be selected on the basis of the volume of the formulation to be applied, the number of acne lesions, the general sensitivity of the patient's skin, and other clinical factors well known to practitioners, and well within the scope of good clinical judgment. Concentrations in the range of 5 to 20 percent are most useful, within 20 percent ALA being particularly useful.
The ALA can be applied to the skin by any of the conventional application techniques known in the art, such as swabs, brushes, cotton balls, gauze pads or the like. The Kerastick® application sold by DUSA Pharmaceuticals can also be used.
Light sources suitable for use in ALA-based PDT are also well known and generally available. The wavelengths of light that are capable of penetrating the skin and exciting the protoporphyrin IX molecule are well known to those skilled in the art. Devices capable of providing such light are also readily available, such as the BLU-U® illuminator. The BLU-U emits 417 nm blue light, a wavelength capable of activating protoporphyrin-IX, at a power density of 10 mW/cm 2 .
EXAMPLE 1
A 20 percent ALA Topical Solution (Levulan® Kerastick® (aminolevulinic acid HCl) was applied to a healthy female volunteer exhibiting mild to moderate acne vulgaris of the face. The subject's acne consisted primarily of inflammatory lesions (papules and pustules), however, non-inflammatory lesions (comedones) were also present in small numbers. Prior to application of the ALA solution, the subject's face was washed with soap and water and then dried. Two applications of ALA solution were applied to all exposed skin areas on the patient's face except for the immediate periorbital area. The ALA solution was allowed to dry for several minutes between applications. The subject was instructed to avoid exposure to sunlight or bright indoor light prior to returning for light activation and the subject was informed that sunscreens alone would not protect against exposure to light. The subject was undergoing no other treatment for acne at this time.
The subject returned approximately 30 hours after application of the ALA solution for light treatment using a BLU-U®, photodynamic therapy illuminator. Total light exposure time was 1000 seconds. The subject noted mild stinging and burning during the treatment, none of which was sufficient to cause interruption or cessation of the light exposure.
The subject was evaluated pre and post light exposure. Pre-light exposure examination noted that the inflammatory acne lesions appeared slightly more erythematous than at baseline (ALA solution application). Post-light treatment evaluation revealed increased erythema in the inflammatory acne lesions compared with pre-light treatment. Non-inflammatory lesions appeared to be similar to baseline both pre and post light exposure.
The subject was evaluated approximately 24 hours after light treatment. Punctate moderate erythema was noted in the inflammatory lesions with mild erythema and edema extending slightly into the perilesional skin. Erythema and edema in the interlesional skin areas was largely absent.
The subject was evaluated 3 weeks post light treatment. A significant reduction in the number and severity of acne lesions was noted. All but two of the inflammatory lesions present at baseline had resolved. The remaining lesions exhibited slight erythema in the lesion itself with no perilesional edema or erythema. The subject was satisfied with the reduction in acne provided by the treatment. | This application is directed to a method of treating a patient with acne by applying a photodynamic agent to skin having acne lesions, waiting at least 12 hours, and then exposing the skin to which the photodynamic agent has been applied to light that causes an activation reaction. | 0 |
TECHNICAL FIELD
The present invention belongs to the technical zone of internal torque balancing of the short fibre yarns, further relates to the zone of controlling the spinning and knitting processes of the spinning machine.
BACKGROUND ART
Twisting is an important step of short fibre spinning. In this process, the yarns, are elastically twisted and transformed to attain sufficient strength, wear resistance and smoothness. However, as a negative effect, a large amount of residual torque or twist liveliness is also brought about in the yarns simultaneously. Such twist liveliness of the yarns renders a significant influence on the possessing quality of the latter products. For example, if yarns with twist liveliness are used on knitting, loops of the fabric will lose their balance because of the variation of torsion stress in the yarns. In order to attain the natural structure with the minimum energy condition, the loops tend to rotate to release the internal torsion stress. As a result, one end of the loops will tilt and protrude from the fabric surface, while the other end will stay inside the fabric. Such deformation of the loops will increase the spirality of the fabric; a deformation similar to the rib effect, which should be prevented to the utmost in the spinning industry. Thus, the balancing of torque inside the yarns is particularly important.
Yarns are made from a large quantity of fibres polymerized by their friction inbetween. Hence, the residual torque of the yarns or the spirality of the fabric is mainly affected by said characteristic of the fibres, such as the type and cross sectional shape of the fibres, the polymerizing manner of the fibres and the internal structure of the yarns, etc.
First of all, different types of fibres have a different modulus (i.e. tensile, bending and shear) and cross sectional shape, thus lead to different degree of stress in the yarns. According to the report of Arauj and Smith in the Textile Research Journal, Vol. 59, No. 6, 1989, in the cotton/polyester blended yarns, increasing the ratio of polyester will enhance the twist liveliness of rotor and ring yarns, thus improving the spirality of the yarns. This is because polyester has a higher modulus, and said two types of fibre has different cross sectional shapes.
Next, different yarn structures have a different distribution of stress. Experimental results, such as Barella and Manich in the Textile Research Journal, Vol. 59, No. 12, 1989, Lord and Mohamed in the Textile Research Journal, Vol. 44, No. 7, 1974 and Sengupta, and Sreenivasa in the Textile Research Journal, Vol. 64, No 10, 1994 show that, friction yarns (DREF-II) has the largest residual torque and trend of deformation in the priority sequence as ring yarns, rotor yarns and air-jet yarns. The different residual torques of said four types of yarn show the difference among their structures. It is generally agreed that single ring yarns are composed of a plurality of uniformly enveloped concentric helical threads, which fibre migration is a secondary feature. Hence, when the ring yarns are reverse-twisted, their strength will gradually decrease to zero, by then the yarns will be all dispersed. In relative to ring yarns, unconventional spinning system produce yarns with core-sheath structures, such as rotor spinning yarn, air jet spinning yarn and friction spinning yarns. The packing density of said yarns is uneven, mainly characterized in the partial entanglement and enwrapment of the fibres. As a result, during reverse twisting, the strength of said yarns would not be completely disappeared, as disclosed in the Textile Research Journal, Vol. 58, No. 7, 1988 by Castro etc.
In addition, many factors can affect the degree of movement freedom of the loops of the fabric and also the final spirality of the fabric. Said factors include fabric structure, parameters of the knitting machine, and the fabric relaxation and fabric setting due to finishing. All the aforesaid factors affecting the spirality of fabric are reported in detail as disclosed by Lau and Tao in the Textile Asia, Vol. XXVI, No. 8, 1995.
Same as other materials, the residual torque of the yarns can be reduced or eliminated with different methods. In the past several ten years, a variety of torque balancing methods have been developed. According to basic theory, they can generally refer to two categories: permanently processing method and physical torque balancing method.
Permanently processing method mainly accomplishes the purpose of releasing residual torque by transforming the elastic torsional deformation into plastic deformation. Said method mainly relates to all sorts of processing technique of material, such as thermal processing, chemical processing and wet processing etc. In the Textile Research Journal, Vol. 59, No. 6, 1989, Araujo and Smith have proved that in relative to air-jet and rotor yarns, the heat processing of single cotton/polyester blended yarns can effectively reduce the residual torque of the yarns, However, in relative to natural fibres such as cotton or wool, permanent processing is too complicated. It may involve stream processing, hot water processing and chemical processing (such as mercerization in the case of cotton yarns and treatment with sodium bisulphite in case of the wool yarns) In addition, in relative to natural yarns, permanent processing cannot completely eliminate the residual torque of the single yarns; meanwhile it may cause damage and abruption to the yarns.
In relative to permanent processing, physical torque balancing is a pure mechanical processing technique. The main point of said method is fully utilizing the structure of yarns to balance the residual torque generated in different yarns while maintaining the elastic deformation characteristic of the yarns. Currently in the industry, separate machines are required to enforce torque balancing of the yarns; the cost is thus higher. Said method comprises plying two identical singles yarns with a twist equal in number but in the opposite direction to that in the singles yarns; or feeding two singles yarns with twist of the same magnitude but in opposite direction onto the same feeder.
Recently, some new torque balancing methods for yarns also emerges. In the Textile Research Journal, Vol. 65, No. 9, 1995, Sawhney and Kimmel has designed a series spinning system for processing torque-free yarns. The inner core of said yarns is formed by processing with an air-jet system while outside the core is enwrapped with crust fibres similar to DREF-III yarns. In the Textile Research Journal, Vol. 62, No. 1, 1992, Sawhey etc. have suggested a method of processing ring cotton crust/polyester inner core yarns Said yarns accomplish balancing condition by utilizing core yarns with opposite twisting direction from synthetic yarns, or applying heat processing on the polyester portion of said yarns. However, it is readily seen that the machines and processing techniques related to the aforesaid method are generally more complicated. In the Textile Research Journal, Vol, 57, No. 10, 1997, Tao has processed the layer structure of the inner core-crust of rotor yarns to generate torque-free single yarns, yet said technique is not suitable for ring yarns.
CONTENTS OF THE INVENTION
The purpose of the present invention is to overcome the defects and shortages of the prior art herein above by proposing a completely new mechanical processing method of single torque-free yarns, and applying it into the art of ring spinning. The basic theory of said method is to process the single yarns with controllable multi-bundle fibre structure, and make the sum of residual torque
( ∑ j = 1 N M j )
produced by N fibre bundles in the yarns balanced with the residual torque (M) of the whole synthetic single yarns, i.e.
∑ j = 1 N M j - M = 0.
The technical solution of said method is to install a fibre bundle-spitting mechanism and a false twisting device on to a conventional ring spinning machine; said fibre bundle-spitting mechanism is placed preceding the spinning triangular zone for splitting a roving into a plurality sub-fibre bundles; the false twister is installed between a front roller and a ring traveller of the ring spinning machine for false twisting the sub-fibre bundles before true twisting of the original ring spinning machine, and then attaining balance of the internal torque of the final yarns by regulating the rotating speed of the false twister.
The mechanical processing method for single torque-free yarns provided by the present invention develops a new way on the art of balancing the internal torque of short fibre yarns. It shows the following advantages:
1. Since the improvement of said method on the current ring spinning machines spinning machine only relates to installing a fibre bundle-spitting mechanism and a false twister, said technical method is simple and convenient, the versatility is strong.
2. Said technique can generate single torque-free yarns in one spinning machine with one processing step, hence comparing to the traditional torque balancing method, said method has the advantages of saving processing time and reducing processing cost, under the condition of attaining the same torque-free yarns.
3. The single torque-free yarns processed by said method can break through the maximum yarn count of Ne limit of the torque-free yarns produced by the existing physical balancing technique.
4. Since said method is to install a false twister onto a conventional ring spinning machine, it can enhance the torque of the spinning triangular zone, improve the strength of the yarns, thus ensures the yarns in normal spinning under low twist multiplier. Hence, said method can generate yarns with low twist, which is unable to be obtained by traditional ring spinning machine.
5. Since said technique is a pure mechanical technique, it can be applied to all types of short fibre material production, such as cotton, wool and synthetic fibre etc. In addition, said method can prevent damage or deterioration of fibres caused by heat or chemical processing etc. in such as permanent processing.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 is the structural schematic view of a two-bundle separate-feeding mechanism for roving;
FIG. 2 is the structural schematic view of a multi-bundle spitting mechanism for untwisted yarns;
FIG. 3 is the structural schematic view of another multi-bundle spitting mechanism for untwisted yarns;
FIG. 4 is the structural schematic view of double-stage multi-bundle spitting mechanism for untwisted yarns;
FIG. 5 ( a ) is the front view of a mechanical false twister,
FIG. 5 ( b ) is the top view of the mechanical false twister shown in FIG. 5 ( a );
FIG. 6 ( a ) is the enlarged front view of the mechanical false twister shown in FIG. 5 ( a );
FIG. 6 ( b ) is the top view of the mechanical false twister shown in FIG. 6 ( a );
FIG. 7 ( a ) is the front view of another mechanical false twister;
FIG. 7 ( b ) is the cross-sectional view along S—S in FIG. 7 ( a );
FIG. 8 is the cross-sectional schematic view of an air-jet false twister;
FIG. 9 ( a ) is the schematic view of the torque balance of a single yarn having a doubled fibre structure;
FIG. 9 ( b ) is the cross-sectional view along S—S in FIG. 9 ( a );
FIG. 10 is the process schematic view of the torque balance of a single yarn having a multi-bundle fibre structure;
In the Figures,
1 . driven rotor; 2 . bed frame; 3 . guide tube; 4 . driving belt; 5 . electric motor; 6 . driving rotor; 7 . magnet; 8 . pin(s); 9 . coupling hinge; 10 . curve flute; 11 . a cylinder-half, 12 ; another cylinder-half; 13 . compressed air; 14 . a tangential direction indicating the compressed air entering; 15 . a fibre bundle having Z-twist; 16 . another fibre bundle having Z-twist; 17 . composite single yarns having S-twist; 18 . roving; 19 . sub-fibre bundles forming synthetic single yarns under twisting of the false twister; 20 . single yarns ( 19 ) after reverse twisting; 21 . resultant yarn sample; 22 . showing control of the rotating speed of the false twister based on the residual torque of the resultant yarn sample ( 21 ); 100 . double-bundle separate-feeding mechanism of roving; 200 . a multi-bundle spitting mechanism of untwisted yarns; 300 . another multi-bundle spitting mechanism of untwisted yarns; 400 . mechanical false twisting device; 500 . a mechanical false twister; 600 . another mechanical false twister; 700 . air-jet false twister; 800 . ring traveller of the ring spinning machine; 900 . showing the residual torque test of the wet-twisting method of the resultant yarn sample ( 21 ); 1000 . ring spinning machine; 2000 . double-stage multi-bundle spitting mechanism for untwisted yarns; 3000 . Yarn drafting device; 4000 . sub-fibre bundles obtained after roving split through multi-bundle spitting mechanism; 5100 . A group of fibre bundle obtained by sub-fibre bundle of a rove bundle passing through a first stage twisting of double-stage multi-bundle spitting mechanism; 5200 . Another group of fibre bundle obtained by sub-fibre bundle of another rove bundle passing through a first stage twisting of double-stage multi-bundle spitting mechanism; 6000 . A yarn obtained on the action of a second stage twisting of double-stage multi-bundle spitting mechanism for the two groups of fibre bundles. I. showing the entrance direction of the fibre bundles (or the yarns); II. showing the exit direction of the fibre bundles (or the yarns); M 1 . the internal torque generated in the fibre bundle ( 15 ); M 2 . the internal torque generated in the fibre bundle ( 16 ); M. the internal torque generated in the synthetic single yarns ( 17 ).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The method of the present invention will be illustrated in details hereunder accompanying with the figures.
In FIG. 1 , a double-bundle separate-feeding mechanism ( 100 ) of roving can installed preceding a yarn drawing/drafting zone and a spinning triangular zone of the ring spinning machine to split two bundles of roving with a certain distance. The roving enter the two-bundle separate-feeding mechanism ( 100 ) from the entrance direction (I), are separated with a certain distance and exit from the exit direction (II), and then enter from the back of the drafting zone.
In FIGS. 2 and 3 , a multi-bundle spitting mechanism ( 200 or 300 ) of untwisted yarns is installed on to the drafting frame of the ring spinning machine behind the drafting zone and preceding the spinning triangular zone for splitting the untwisted yarns into a plurality of sub-fibre bundles. The multi-bundle spitting mechanism ( 200 or 300 ) contacts with front roller(s) of the ring spinning machine and is driven to rotate. After drafting, the untwisted yarns enter the multi-bundle spitting mechanism ( 200 or 300 ) from the entrance direction (I) into a plurality of discontinuous ( 200 ) or continuous ( 300 ) flutes disposed annular on the rollers, afterwards they are separated into a plurality of sub-fibre bundles, finally each of the sub-fibre bundles are drawn out from the exit direction (II) into the back of the spinning triangular zone.
In FIG. 4 , a double-stage multi-bundle spitting mechanism ( 2000 ) is composed of a double-bundle separate-feeding mechanism ( 100 ) installed preceding the yarn drawing/drafting zone and a multi-bundle spitting mechanism ( 200 or 300 ) positioned between the yarn drawing/drafting zone and the spinning triangular zone. Firstly, two bundles of roving are split with a certain distance by the double-bundle separate-feeding mechanism ( 100 ) and then are drafted into widen fibre bundles by a yarn-drafting device ( 3000 ) and afterwards are fed into the multi-bundle spitting mechanism ( 200 or 300 ). Fibre bundles of the two widen bundles are respectively split into several sub-fibre bundles ( 4000 ) by the multi-bundle spitting mechanism ( 200 or 300 ) and then fabricated into a yarn ( 6000 ) on the action of through the double stage twisting. The double-stage multi-bundle spitting mechanism ( 2000 ) has a double stage yarn spinning triangular zone, where the first stage spinning triangular zone is to twist several sub-fibre bundle ( 4000 ) of the two bundle of roving respectively into two groups of fibre bundles ( 5100 and 5200 ), and the second spinning triangular stage is to twist the two groups of fibre bundles ( 5100 and 5200 ) twisted at the first stage spinning triangular zone into a yarn ( 6000 ).
In FIGS. 5 , 6 and 7 , the driving rotor ( 6 ), driven rotor ( 1 ), guide tube ( 3 ) and magnet ( 7 ) are secured onto the bed frame ( 2 ). The bed frame ( 2 ) is further secured together with the electric motor ( 5 ) onto a steel collar to form a false twisting device ( 400 ). The false twisting device ( 400 ) can be installed between the front roller and the ring traveller of the ring-spinning machine. Under the sorption of the magnet ( 7 ), the false twister ( 500 or 600 ) is in close contact with the driving rotor ( 6 ) and the driven rotor ( 1 ). The electric motor ( 5 ) drives the driving rotor ( 6 ) to rotate via the driving belt ( 4 ). Further, the driving rotor drives the false twister ( 500 or 600 ) together with the driven rotor ( 1 ) to rotate at high speed by means of friction. The yarns enter the false twister ( 500 or 600 ) from the entrance direction (I) and is twisted by the turning effort of the false twister ( 500 or 600 ). Twisted yarns are drawn out from the exit direction (II) via guide tube ( 3 ).
In FIG. 7 , another false twister ( 600 ) is composed of two cylinder-halves ( 11 and 12 ) provided with curve flutes ( 10 ). Said two cylinder-halves ( 11 and 12 ) are coupled with a hinge ( 9 ) and secured with pins ( 8 ). Said false twister ( 600 ) can be opened and closed for installing yarns. After removing the pins ( 10 ), yarns can be placed into the curve flutes ( 10 ) for twisting. Said yarns have a frictional length inside the curve flutes ( 10 ). The yarns enter the false twister ( 600 ) from the entrance direction (I) and being twisted under the turning effort of the false twister ( 600 ), finally being drawn out from the exit direction (II).
In FIG. 8 , an air-jet false twister ( 700 ) can be installed between the front roller and the ring traveller of the ring spinning machine, wherein compressed air ( 13 ) enters the air-jet false twister ( 700 ) along a tangential direction ( 14 ) into a twisting area. The yarns enter the air-jet false twister ( 700 ) from an entrance direction (I) and being twisted with the tangential direction ( 14 ) under the drive of the compressed air ( 13 ), finally being drawn out from an exit direction (II).
In FIG. 9 , single yarns ( 17 ) are composed of two bundles of fibres ( 15 , 16 ). The sum of the internal torque (M 1 +M 2 ) generated by a fibre bundle having Z twist ( 15 ) and another fibre bundle having Z twist ( 16 ) is in equilibrium with the internal torque of the synthetic single yarns having S twist ( 17 ) composed thereof, i.e. M 1 +M 2 −M=0.
In FIG. 10 , The method of the present invention is comprise the steps of: installing the fibre-spitting mechanism ( 100 , 200 , 300 , 2000 ) preceding the spinning triangular zone of the ring spinning mechanism ( 1000 ) to split the roving ( 18 ) into a plurality of sub-fibre bundles; meanwhile, installing a false twister ( 500 , 600 or 700 ) between the front roller and the ring traveller ( 800 ) of the ring spinning machine. The rotating direction of said false twister ( 500 , 600 or 700 ) is same as the ring traveller ( 800 ). Its purpose is to false twist the fibre bundles before true twisting of the original ring spinning machine, and to manually control the rotating speed of the false twister ( 500 , 600 or 700 ) based on the result of the wet-twisting test of the residual torque on the resultant yarn sample ( 21 ), thus the twisting direction of each fibre bundle is opposite to the single yarns composed thereof, and the sum of the residual torque generated by each fibre bundle is in equilibrium with the residual torque of the whole composite single yarn. The process of the present method is illustrated in details hereunder accompanying with FIG. 10 .
1. Prior to the spinning triangular zone, the fibre bundle-splitting mechanism ( 100 , 200 or 300 ) splits the roving into two or more sub-fibre bundles;
2. In the spinning triangular zone, each the fibre bundle gains a twist value by the action of the false twister ( 500 , 600 or 700 ), and then synthesizes into single yarns ( 19 ). Meanwhile, each fibre bundle inside the yarns has the same twisting direction as the yarns synthesized thereby;
3. Between the false twister ( 500 , 600 or 700 ) and the ring traveller ( 800 ) of the ring spinning machine, each sub-fibre bundle and the single yarns ( 19 ) synthesized thereby are reverse-twisted simultaneity, thus a reverse-twist value is formed on each sub-fibre bundle and the single yarns ( 19 ) synthesized, which become single yarns ( 20 ), and finally winded on the spindle of the spinning machine;
4. Wet twisting method ( 900 ) is used to test the residual torque of the resultant yarn sample ( 21 ). Afterwards, the rotating speed of the false twister ( 500 , 600 or 700 ) is (manually) regulated according to the amount of residual torque in the resultant yarn sample ( 21 );
5. Steps 1 - 4 are repeated until the residual torque of the yarns is in balance.
ISO standard ISO 03343-1984 can be used as a reference for the basic concept of the residual torque test ( 900 ) by the wet twisting method in the aforesaid step 4 . Under room temperature, the experimental device is placed into water. The whole experiment is held in water. Finally, the wet twist value of the yarns is used as measuring criteria of the residual torque of the yarns.
The present invention has been experimented on a Zinser-319 type ring spinning machine for many times, and a satisfying result is attained The experimental material is 100% pure cotton rove, which parameters are listed in Table 1. The rotating speed of the spindle of the ring spinning machine is 7000 r/min The single yarn count is 30 tex. Yarns of three different twist multiplier (1.9, 2.4 and 3.1) are used for spinning.
TABLE 1
Count of roving
538
tex
Evenness
3.84
Cvm%
Fibre fineness
0.17
tex
Fibre length
28
mm
Elongation percentage
5.6%
In the experiment, the selected fibre bundle-splitting mechanism ( 300 ) is installed on the drafting frame of the ring spinning machine and driven by the friction of the front roller to rotate. The fibre bundle-splitting mechanism ( 300 ) can continuously and smoothly splits the roving into three sub-fibre bundles. A false twister ( 600 ) is chosen to be used and installed on the steel collar between the front roller and ring traveller of the ring spinning machine. The false twister ( 600 ) rotates to drive the yarns inside the curve grooves to twist. Wet twisting method is used to test the residual torque of the resultant yarn sample, and then the rotating speed of the false twister ( 600 ) is regulated according to the amount of residual torque of the resultant yarn sample. In the experiment, with regard to each twist multiplier, when the rotating speed of the false twister ( 600 ) is increased to 20000 r/min, the internal torque of the yarns would be in balance.
With regard to each twist multiplier, a conventional single yarn and a single torque-free yarn having a three-fibre bundle structure are processed respectively for comparison. In Practice, under conventional spinning, i.e. without installing a false twister, with regard to a low twist multiplier as 1.9, broken ends would occur to the yarns, thus spinning cannot be go on normally. For all twist multiplier, the progress for single torque-free yarns are smoothly. The residual torque of the different yarn by the experiments and the main properties are listed in Table 2, wherein “X” means yarns cannot be normally processed.
TABLE 2
Test of residual
Type
torque with wet
Elongation
of
twist
twist
twisting method
strength
percentage
Evenness
Hairiness
yarns
multiplier
(tpm)
(turns/25 cm)
(cN/text)
(%)
(%)
(−)
Conventional
1.9
330
x
x
x
x
x
single ring yarn
2.4
417
33.9
21.3
6.2
10.8
7.6
3.1
539
47.9
24.9
6.4
10.3
6.5
Single torque-free
1.9
330
0
18.2
5.0
9.8
6.6
ring yarn
2.4
417
0
21.3
5.7
9.9
5.8
3.1
539
0
20.4
5.4
10.0
4.8
According to Table 2, the residual torque of all the single torque-free ring yarns has reached zero, thus accomplished the satisfying balance result. Comparing to conventional single ring yarn of corresponding twist multiplier, the strength and elongation percentage of single torque-free ring yarns are lower. However, said difference would not affect the processing quality of the latter product. Comparing to conventional single ring yarn of corresponding twist multiplier, the evenness and hairiness of single torque-free ring yarns are improved. In addition, the processing method of single torque-free ring yarns can process yarns with low twist value 330 tpm, which cannot be processed normally by the conventional ring spinning. | An internal torque balancing method of short fiber yarns related to the art of textile and the manufacturing apparatus thereof. The present invention proposes a completely new mechanical processing method of single torque-free yarns, and applies it into the process of ring spinning. Said method accomplishes a machine and a possibility of processing single torque-free yarns within one processing step by simple improvement on the existing ring spinning machine. Said technique is applicable to the production of all types of short fiber materials, and can overcome the maximum bundle yarn count of Ne limit of the torque-free yarns processed by the existing physical balancing technique. Meanwhile, said technique can process the yarns with low twist, which is unable to be processed normally by the conventional ring spinning machine. The torque-free singles ring spinning machine has good mechanical behavior, good handle, and evenness without residual torque. | 3 |
FIELD OF THE INVENTION
[0001] The present invention relates to medical devices; more particularly, the invention relates to protective sheaths for scaffolds and stents crimped to a delivery balloon.
BACKGROUND OF THE INVENTION
[0002] A variety of non-surgical interventional procedures have been developed over the years for opening stenosed or occluded blood vessels in a patient caused by the buildup of plaque or other substances in the walls of the blood vessel. Such procedures usually involve the percutaneous introduction of an interventional device into the lumen of the artery. In one procedure the stenosis can be treated by placing an expandable interventional device such as an expandable stent into the stenosed region to expand and hold open the segment of blood vessel or other arterial lumen. Metal or metal alloy stents have been found useful in the treatment or repair of blood vessels after a stenosis has been compressed by percutaneous transluminal coronary angioplasty (PTCA), percutaneous transluminal angioplasty (PTA) or removal by other means. Metal stents are typically delivered in a compressed condition to the target site, then deployed at the target into an expanded condition or deployed state to support the vessel.
[0003] The following terminology is used. When reference is made to a “stent”, this term will refer to a permanent structure, usually comprised of a metal or metal alloy, generally speaking, while a scaffold will refer to a structure comprising a bioresorbable polymer and capable of radially supporting a vessel for a limited period of time, e.g., 3, 6 or 12 months following implantation. It is understood, however, that the art sometimes uses the term “stent” when referring to either type of structure.
[0004] Scaffolds and stents traditionally fall into two general categories—balloon expanded and self-expanding. The later type expands to a deployed or expanded state within a vessel when a radial restraint is removed, while the former relies on an externally-applied force to configure it from a crimped or stowed state to the deployed or expanded state.
[0005] Self-expanding stents formed from, for example, shape memory metals or super-elastic alloys such as nickel-titanum (NiTi) which are designed to automatically expand from a compressed state when the radial restraint is withdrawn or removed at the distal end of a delivery catheter into the body lumen, i.e. when the radial restraint is withdrawn or removed. Typically, these stents are delivered within a radially restraining polymer sheath. The sheath maintains the low profile needed to navigate the stent towards the target site. Once at the target site, the sheath is then removed or withdrawn in a controlled manner to facilitate deployment or placement at the desired site. Examples of self-expanding stents constrained within a sheath when delivered to a target site within a body are found in U.S. Pat. No. 6,254,609, US 20030004561 and US 20020052640.
[0006] Balloon expanded stents, as the name implies, are expanded upon application of an external force through inflation of a balloon, upon which the stent is crimped. The expanding balloon applies a radial outward force on the luminal surfaces of the stent. During the expansion from a crimped or stowed, to deployed or expanded state the stent undergoes a plastic or irreversible deformation in the sense that the stent will essentially maintain its deformed, deployed state after balloon pressure is withdrawn.
[0007] Balloon expanded stents may also be stored within a sheath during a transluminal delivery to a target site and/or during the assembly or in the packaging of the stent-balloon catheter delivery system. The balloon expanded stent may be contained within a sheath when delivered to a target site to minimize dislodgment of the stent from the balloon while en route to the target vessel. Sheaths may also be used to protect a drug eluting stent during a crimping process, which presses or crimps the stent to the balloon catheter. When an iris-type crimping mechanism, for example, is used to crimp a stent to balloon, the blades of the crimper, often hardened metal, can form gouges in a drug-polymer coating or even strip off coating through interaction similar to forces at play when the blades and/or stent struts are misaligned during the diameter reduction. Examples of stents that utilize a sheath to protect the stent during a crimping process are found in U.S. Pat. No. 6,783,542 and U.S. Pat. No. 6,805,703.
[0008] A polymer scaffold, such as that described in US 20100004735 may be made from a biodegradable, bioabsorbable, bioresorbable, or bioerodable polymer. The terms biodegradable, bioabsorbable, bioresorbable, biosoluble or bioerodable refer to the property of a material or stent to degrade, absorb, resorb, or erode away after the scaffold has been implanted at the target vessel. The polymer scaffold described in US 2010/0004735, as opposed to a metal stent, is intended to remain in the body for only a limited period of time. In many treatment applications, the presence of a stent in a body may be necessary for a limited period of time until its intended function of, for example, maintaining vascular patency and/or drug delivery is accomplished. Moreover, it is believed that biodegradable scaffolds, as opposed to a metal stent, allow for improved healing of the anatomical lumen and reduced incidence of late stent thrombosis. For these reasons, there is a desire to treat a vessel using a polymer scaffold, in particular a bioresorbable polymer scaffold, as opposed to a metal stent, so that the prosthesis's presence in the vessel is for a limited duration. However, there are numerous challenges to overcome when developing a delivery system having a polymer scaffold.
[0009] Polymeric materials considered for use as a polymeric scaffold, e.g. poly(L-lactide) (“PLLA”), poly(L-lactide-co-glycolide) (“PLGA”), poly(D-lactide-co-glycolide) or poly(L-lactide-co-D-lactide) (“PLLA-co-PDLA”) with less than 10% D-lactide, and PLLD/PDLA stereo complex, may be described, through comparison with a metallic material used to form a stent, in some of the following ways. Suitable polymers have a low strength to volume ratio, which means more material is needed to provide an equivalent mechanical property to that of a metal. Therefore, struts must be made thicker and wider to have the required strength for a stent to support lumen walls at a desired radius. The scaffold made from such polymers also tends to be brittle or have limited fracture toughness. The anisotropic and rate-dependant inelastic properties (i.e., strength/stiffness of the material varies depending upon the rate at which the material is deformed) inherent in the material only compound this complexity in working with a polymer, particularly a bioresorbable polymer such as PLLA or PLGA. Challenges faced when securing a polymer scaffold to a delivery balloon are discussed in U.S. patent application Ser. No. 12/861,719 (Attorney docket 62571.448).
[0010] When using a polymer scaffold, several of the accepted processes for metal stent handling can no longer be used. A metal stent may be crimped to a balloon in such a manner as to minimize, if not eliminate recoil in the metal structure after removal from the crimp head. Metal materials used for stents are generally capable of being worked more during the crimping process than polymer materials. This desirable property of the metal can mean less concern over the metal stent—balloon engagement changing over time when the stent-catheter is packaged and awaiting use in a medical procedure. Due to the material's ability to be worked during the crimping process, e.g., successively crimped and released at high temperatures within the crimp mechanism, any propensity for elastic recoil in the material following crimping can be significantly reduced, if not eliminated, without affecting the stent's radial strength when later expanded by the balloon. As such, following a crimping process the stent-catheter assembly often does not need packaging or treatment to maintain the desired stent-balloon engagement and delivery profile. If the stent were to recoil to a larger diameter, meaning elastically expand to a larger diameter after the crimping forces are withdrawn, then significant dislodgment force could be lost and the stent-balloon profile not maintained at the desired diameter needed to deliver the stent to the target site. Consequently, sheaths for metallic stents are often solely protective, preventing contamination or mechanical damage to the stent and coating. They do not need to be closely fitted to prevent stent recoil on aging and storage.
[0011] While a polymer scaffold may be formed so that it is capable of being crimped in such a manner as to reduce inherent elastic recoil tendencies in the material when crimped, e.g., by maintaining crimping blades on the scaffold surface for an appreciable dwell period, the effectiveness of these methods are limited. Significantly, the material generally is incapable of being worked to the degree that a metal stent may be worked without introducing deployed strength problems, such as excessive cracking in the material. Recoil of the crimped structure, therefore, is a problem that needs to be addressed.
[0012] In view of the foregoing, there is a need to address the challenges associated with securing a polymer scaffold to a delivery balloon and maintaining the integrity of a scaffold-balloon catheter delivery system up until the time when the scaffold and balloon are delivered to a target site within a body. Related to these objectives, there is a need to improve the design and handling of a sheath assembly that is removable (prior to implantation) without causing damage or dislodgment of the crimped scaffold underneath. There is also a need to improve upon sheaths for, or removal of sheaths from stents.
SUMMARY OF THE INVENTION
[0013] According to the invention, a two or three piece sheath can be removed from a scaffold (or stent) without sliding, and whose length can be kept close to the actual length of the crimped scaffold or stent, as needed. In one respect, the sheath includes a constraining sheath portion that applies an inwardly radial force upon a crimped scaffold to minimize recoil of the scaffold, yet may be removed from the scaffold without sliding and while not disrupting or moving an inner protecting sheath relative to the crimped scaffold. The constraining sheath may be removed by a pinching of the sheath or peeling or pulling away of sheath edges, which edges define a sheath opening that is formed to facilitate this removal of the constraining sheath from the inner protecting sheath.
[0014] In other respects, the invention is directed to sheaths and/or sheath assemblies used to maintain a polymer scaffold balloon engagement and delivery system profile as well as methods for assembly of a medical device including a balloon expandable polymer scaffold contained within a sheath. The invention is also directed to a sheath and methods for applying a sheath and sheath assembly that enables the sheath to be easily removed by a medical professional, e.g., a doctor, so as to minimize disruption to a crimped scaffold-balloon engagement or damage to the crimped scaffold. Sheaths and sheath assemblies according to the invention are removed before the medical device is introduced into a body. The invention is further directed to sheaths and their use with stents.
[0015] Sheaths according to the invention are particularly useful for maintaining scaffold-balloon engagement and desired delivery profile following a crimping process where the scaffold is crimped down to achieve a smaller crossing-profile, or crimped diameter. A scaffold formed at a larger diameter, near to or greater than the intended deployed diameter, can exhibit enhanced radial strength when supporting a vessel, as compared to a scaffold formed nearer to a crimped diameter. A scaffold formed near to a deployed diameter, however, increases the propensity for elastic recoil in the scaffold following the crimping process, due to the shape memory in the material. The shape memory relied on for enhancing radial strength at deployment, therefore, also introduces greater elastic recoil tendencies for the crimped scaffold. Recoil both increases the crossing profile and reduces the scaffold-balloon engagement needed to hold the scaffold on the balloon. In one aspect, the invention is directed to maintaining the crossing profile and/or maintaining balloon-scaffold engagement for scaffolds formed near to a deployed diameter.
[0016] In another aspect, the invention is directed to a method of assembly of a catheter that includes crimping a polymer scaffold to a balloon of the catheter and within a short period of removal of the scaffold from the crimper placing a restraining sheath over the scaffold. The steps may further include applying an extended dwell time following a final crimping of the scaffold (dwell times may be about 1, 2, 3, 4, 5, or about 3-5 minutes), followed by applying the restraining sheath. Both the crimping dwell time and applied restraining sheath are intended to reduce recoil in the crimped scaffold. The restraining sheath may include both a protecting sheath and a constraining sheath.
[0017] In another aspect, the invention is directed to a sterilized medical device, e.g., by E-beam radiation, contained within a sterile package, the package containing a scaffold crimped to a balloon catheter and a sheath disposed over the crimped scaffold to minimize recoil of the crimped scaffold. The sheath covers the crimped scaffold and may extend beyond the distal end of the catheter. The sheath is tubular and does not completely circumscribe the scaffold. The sheath has an opening spanning the length of the sheath. The opening has an arc length of less than 180 degrees and more preferably less than about 90 degrees with respect to the circumference of the scaffold or balloon partially circumscribed by the sheath. The sheath may be removed from the scaffold by pinching the sheath between a thumb and forefinger (see e.g., FIG. 3A ), or by a bending or peeling back the edges of the sheath at edges of the opening using fingertips.
[0018] Sheaths arranged according to the invention provide an effective radial constraint for preventing recoil in a crimped scaffold, yet are comparatively easy to manually remove from the scaffold. A sheath that applies a radial constraint can be difficult to remove manually without damaging the crimped scaffold, dislodging or shifting it on the balloon. In these cases it is desirable to arrange the sheaths in a manner to apply an effective radial constraint yet make the sheaths capable of manual removal in a safe and intuitive manner. By making the sheath removal process easy to follow and intuitive, the possibility that a health professional will damage the medical device when removing the sheath is reduced.
[0019] A two-piece sheath for a polymer scaffold is described in U.S. Pat. No. 8,414,528 (attorney docket 62571.534) and U.S. application Ser. No. 13/924,421 (attorney docket 62571.757). Both components of the sheath may be made of PTFE. After the sheath is placed over the scaffold, the device (including the catheter) is inserted into a protective spiral coil made of LLDPE (linear low density polyethylene). At the point of use, prior to inserting the catheter into a body, a medical professional removes the catheter from the protective coil by pulling on a catheter hub and gently sliding the catheter out of the coil. In the next step, the catheter is grasped just proximal to the sheathed portion of the device, and with the other hand, an outer constraining sheath is slid distally. This frees an inner protecting sheath from the crimped scaffold because it is split in the region where the crimped scaffold resides. As the inner sheath is split or opens, it readily slides off. The catheter is then ready for being introduced into a body.
[0020] One possible issue presented by the sheath proposed in U.S. Pat. No. 8,414,528 is the required sliding action (i.e., sliding the outer sheath over the inner sheath) to remove the sheath form the scaffold. The sliding action necessitates a minimum clearance between the two sheath layers to ensure that frictional force created by the sliding does not exceed the material strength of the device (e.g., the catheter seals) and damage the device during sheath removal. A second possible issue with the proposed sheath design is its overall length. In order to free the crimped scaffold from the sheath pair in the designed way by sliding motion, the inner sheath (and, consequently, the entire length of the sheath) needs to be longer than the actual portion of the device requiring sheathing in order to ensure that the outer sheath has enough translational distance to slide distally along the inner sheath while maintaining a protecting sheath over the scaffold. For longer scaffolds (e.g., scaffolds indicated for the superior femoral artery) a correspondingly longer sheath is needed, which requires larger, more expensive packaging. Thus, the length of the sheath can impact the overall packaging size of the product.
[0021] In accordance with the foregoing, there is a scaffold (or stent), medical device, method for making such a scaffold, or method for assembly of a medical device (such as a scaffold-balloon catheter assembly) comprising such a scaffold having one or more, or any combination of the following things (1)-(28):
(1) A two or three-piece piece sheath disposed over the scaffold or stent. (2) A constraining sheath may be removed by a pinching of the sheath or peeling or pulling away of sheath edges, which edges define a sheath opening that is formed to facilitate this removal of the constraining sheath from an inner protecting sheath. The outer sheath is removed before the inner sheath. To facilitate this removal a seam of the inner sheath is not placed within an opening of the outer sheath. (3) A constraining and protecting sheath are removed simultaneously by pinching or peeling. To facilitate this this alternative type of removal, although not necessary, it may be preferred to place a seam of the inner sheath within an opening of the outer sheath and/or the constraining sheath opening angle is relative small, such as about 5, 10, 15, or between 5 and 20 degrees. (4) Ratio of crimped diameter to balloon nominal inflation diameter or expanded diameter is greater than about 2, 2.5 or greater than about 3 or 4; and/or the ratio of pre-crimp diameter to balloon nominal diameter is about 0.9 to 1.5. (5) The catheter and scaffold are configured as a medical device suitable for being implanted within a body only after both a sheath disposed over the scaffold and a tube are removed. The medical device is not configured or even capable of being introduced into the body until after both the sheath pair and/or tube are removed from the medical device. (6) A scaffold crimped to a balloon and a sheath disposed over the scaffold. The scaffold is configured for being introduced into a body only after the sheath is removed from the scaffold. And means for removing the sheath from the crimped scaffold in a safe manner. The means for removing in a safe manner may include an opening in the sheath having an arc-length of about 90 degrees or less than 180 degrees to facilitate or enable removal of the sheath by a pinching or pulling or peeling up upon edges defining the sheath opening using fingertips. The means may further include forming a non-circular outer surface, concave outer surface(s), a notch or ridges on the sheath outer surface. (7) A method of maintaining a low crossing profile or retention between a scaffold and balloon, comprising: crimping; dwelling to reduce recoil; placing a first sheath over the scaffold; removing the first sheath; placing a second sheath; wherein prior to implantation the second sheath is removed. The second sheath is a two-piece sheath, such as the sheath described in FIG. 1A-1C or 4 A- 4 C. (8) The protecting sheath is a one or two piece sheath and/or the protecting sheath has a thickness that is about equal to, or 20%, 30%, 40% or 50% of the constraining sheath thickness. (9) A constraining sheath length that is about, or is less, equal to, or greater than a protecting sheath length. (10) The sheath may comprise PTFE, PVDF, fluoropolymer, polyethylene, polypropylene, nylon, nylon copolymers, Pebax, polyacetal, or polyimide. (11) The polymer comprising the scaffold is bioresorbable, or the stent comprises a durable, non-bioresorbable, or non-bioerodible polymer. (12) The scaffold may be crimped to a balloon catheter, the catheter may be contained within a tube and the catheter (with or without the tube) may be contained within an E-beam, ETO, x-ray or gamma-ray sterilized package. (13) Crimping of the scaffold to the balloon includes placing a one-piece sheath over the scaffold immediately after crimping, removing the one-piece sheath and then placing a two-piece sheath over the scaffold, where the two-piece sheath is adapted for being removing by a medical professional prior to introduction to a body. (14) A method of assembly including placing a catheter within a first tube wherein only the distal end of the catheter is outside the tube, crimping; and attaching a second tube to the first tube to cover the distal end. The tube may include a clearance at either distal or proximal end. (15) A sheath pair satisfying two objectives: (1) apply a radial compressive force on a scaffold to minimize recoil, yet (2) be easily removed by a health professional in an intuitive manner, with reduced risk of causing damage to the scaffold or catheter when the sheath is removed. (16) For the same material used for a protecting and constraining sheath, in which case a protecting sheath thickness is about equal to, or at least 20%, 30%, 40% or 50% and less than the thickness of the constraining sheath. (17) A constraining sheath that circumscribes more than 50%, but less than the entire scaffold. An opening in the sheath therefore spans an arc-length less than about 180 degrees. In other aspects, a constraining sheath circumscribes more than 50%, 55%, 60%, 65%, 70% or 80% and less than the entire scaffold; the opening spans about 3%, 6%, 8%, 11%, 13%, 17%, 19%, 22%, 25%, 31%, 33% or 42% of the entire circumference of a scaffold; or the opening (expressed as an arc length) may be about 20-50, 80-120, 10, 20, 30, 50, 70, 90, or 110 Deg. (18) When fully assembled the constraining and protecting sheaths are preferably arranged so that an entire one of the portions or halves of a two-piece protecting sheath are fully covered by the constraining sheath and the other only partially covered by the constraining sheath, or a seam (separating portions of the protecting sheath) or cut (separating halves of the protecting sheath) are not within the opening or uncovered part of the constraining sheath. (19) A constraining sheath has an opening, a non-circular outer surface to facilitate a peeling-away or pinching of the constraining sheath to remove the constraining sheath from the protecting sheath, and/or a notch that is intended to cause a kinking or buckling of the sheath at the notch when radial-inward pressure is applied by fingertips that pinch, peel away or pull upon sheath edges defining a sheath opening. A constraining sheath according to embodiments may include the opening and a notch, the opening and a non-circular outer surface, or a combination of all three features. (20) A constraining sheath that has a longitudinally extending notch. The notch may be located at a central point or along an axis of symmetry for the sheath. The sheath is configured to kink, fold or buckle at the notch when the constraining sheath is being removed from the protecting sheath. (21) A constraining sheath that has one or more longitudinally-extending ridges. The ridges may be symmetrically disposed about an axis passing through the center of the catheter when the sheath is disposed over and constraining the scaffold. There can be one or two ridges on each side of the axis of symmetry. (22) A constraining sheath that forms one or more concave surfaces on the outer surface of the sheath. The concave surfaces may be symmetrically disposed about an axis passing through the center of the catheter when the sheath is disposed over and constraining the scaffold. (23) An apparatus, including a catheter including a scaffold comprising a polymer, the scaffold being crimped to a balloon and a constraining sheath disposed over the scaffold, the sheath comprising two edges defining an opening, the edges being circumferentially spaced from each other by between 5 Degrees and 150 Degrees; wherein the catheter is capable of being introduced into a body only after the sheath is removed from the scaffold. (24) Any of the following things separately or in any combination with things (23), (25) or (26): wherein each of the two edges extend over the entire length of the sheath; wherein the between 50 Degrees and 150 Degrees circumferential spacing is about constant over the entire length; wherein the sheath has a non-circular outer surface; wherein the sheath has a notch and the sheath is symmetric about an axis passing through the notch and a longitudinal axis of the scaffold; wherein the sheath outer surface comprises a concave surface or the sheath outer surface comprises at least two longitudinally-extending ridges; further comprising, a protecting sheath disposed over the scaffold, wherein the protecting sheath is in direct contact with the scaffold and inside the constraining sheath; wherein the protecting sheath is a one or two piece sheath comprising halves or separate portions, respectively, wherein when the protecting sheath is disposed over the scaffold, edges of adjacent halves or portions are brought together to form a tubular body; wherein the edges of adjacent halves or portions are not within the opening defined by the constraining sheath edges; wherein the protecting sheath thickness is about 50% of the constraining sheath thickness; wherein the sheath is configured for being removed from the scaffold by pinching the two edges together, or by peeling the two edges away from each other as the sheath is lifted off the scaffold; wherein the sheath is not configured for being moved longitudinally relative to the scaffold when the sheath is being removed from the scaffold; a tube comprising the apparatus of claim 1 contained within a lumen of the tube. (25) A method of making a medical device, comprising the steps of crimping the medical device to a balloon; and placing a constraining sheath over the crimped medical device, the constraining sheath comprising two edges defining an opening, when placed over the crimped medical device the edges are circumferentially spaced from each other by between 5 Degrees and 150 Degrees; wherein the medical device is capable of being implanted within a body only after the constraining sheath has been removed from the medical device. The method may further comprise: crimping the medical device to a balloon; placing a temporary sheath over the medical device; removing the temporary sheath from the medical device; and placing the constraining sheath over the medical device after the temporary sheath is removed; (26) A tubular medical device, comprising: a sheath disposed over the medical device, wherein the medical device is configured for being radially expanded; the sheath circumscribing at most between about 70% to 98% of the medical device; wherein the medical device is capable of being introduced into a body only after the sheath is removed from the medical device. The medical device may be a stent or a scaffold. (27) A method for removing a sheath from a crimped scaffold, comprising: applying pressure to opposite sides of the sheath; and pinching together, or peeling away edges of the sheath from the scaffold to remove the sheath from the scaffold. (28) Edges of a constraining sheath or an outer sheath, when placed over a stent or scaffold, in a crimped condition, are circumferentially spaced from each other by between 5 to 20 Degrees or 50 to 150 Degrees.
INCORPORATION BY REFERENCE
[0051] All publications and patent applications mentioned in the present specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. To the extent there are any inconsistent usages of words and/or phrases between an incorporated publication or patent and the present specification, these words and/or phrases will have a meaning that is consistent with the manner in which they are used in the present specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] FIG. 1 is a side cross-sectional view of a balloon catheter assembly, including a first embodiment of a constraining sheath and a protecting sheath disposed over a scaffold crimped to a balloon.
[0053] FIG. 1A is front view of the protecting and constraining sheaths, crimped scaffold and balloon of FIG. 1 .
[0054] FIG. 1B is an exploded assembly view of the protecting and constraining sheaths and balloon catheter of FIG. 1 .
[0055] FIG. 1C is a perspective view of the balloon catheter of FIG. 1 with protecting and constraining sheaths.
[0056] FIG. 2 is a second embodiment of a protecting sheath.
[0057] FIGS. 3 and 3A are drawings showing a method of removal of a constraining sheath from a protecting sheath, the protecting sheath covering a scaffold crimped to a balloon. FIG. 3A is a front view of the removal of the constraining sheath in FIG. 3 , taken at section IIIA-IIIA.
[0058] FIGS. 4A , 4 B and 4 C are front, perspective and partial perspective views of the balloon catheter with the protecting sheath of FIG. 1 , and a second embodiment of a constraining sheath.
DETAILED DESCRIPTION OF EMBODIMENTS
[0059] For purposes of this disclosure, the following terms and definitions apply:
[0060] The term “about” means 20%, 15%, 10%, 5%, 4%, 3%, 2%, 1.5%, 1%, between 1-2%, 1-3%, 1-5%, or 0.5%-5% less or more than, less than, or more than a stated value, a range or each endpoint of a stated range, or a one-sigma, two-sigma, three-sigma variation from a stated mean or expected value (Gaussian distribution). It is understood that any numerical value, range, or either range endpoint (including, e.g., “about none”, “about all”, etc.) preceded by the word “about” in this disclosure also describes or discloses the same numerical value, range, or either range endpoint not preceded by the word “about”.
[0061] The term “rigid” is a relative term used to describe something that is substantially stiffer than some other thing. For example, a first sheath or tube that is radially rigid, rigid in the radial direction, or simply rigid as compared to a second sheath or tube means that the first sheath/tube is incompressible compared to the second sheath, or essentially does not deform when an external, radially compressive force or pinching force is applied as compared to the second sheath, for the same applied load.
[0062] “Inflated diameter” or “expanded diameter” refers to the diameter the scaffold attains when its supporting balloon is inflated to expand the scaffold from its crimped configuration to implant the scaffold within a vessel. The inflated diameter may refer to a post-dilation balloon diameter which is beyond the nominal balloon diameter, e.g., a 6.5 mm balloon has about a 7.4 mm post-dilation diameter, or a 6.0 mm balloon has about a 6.5 mm post-dilation diameter. The nominal to post dilation ratios for a balloon may range from 1.05 to 1.15 (i.e., a post-dilation diameter may be 5% to 15% greater than a nominal inflated balloon diameter). The scaffold diameter, after attaining an inflated diameter by balloon pressure, will to some degree decrease in diameter due to recoil effects related primarily to, any or all of, the manner in which the scaffold was fabricated and processed, the scaffold material and the scaffold design.
[0063] “Post-dilation diameter” (PDD) of a scaffold refers to the diameter of the scaffold after being increased to its expanded diameter and the balloon removed from the patient's vasculature. The PDD accounts for the effects of recoil. For example, an acute PDD refers to the scaffold diameter that accounts for acute recoil in the scaffold.
[0064] A “pre-crimp diameter” means an OD of a tube, or the scaffold before it is crimped to a balloon. Similarly, a “final crimped diameter” means the OD of the scaffold when crimped to a balloon and removed from a crimping mechanism just prior to sheath placement. The “pre-crimp diameter” can be 2, 2.5, 3.0 times greater than the crimped diameter and about 0.9, 1.0, 1.1, 1.3 and about 1-1.5 times higher than an expanded diameter or post-dilation diameter. A “partial crimp” diameter is a diameter attained after a scaffold or segment is crimped to a diameter less than a pre-crimp diameter and greater than the final crimp diameter. A partial crimp diameter can be an intermediate diameter after crimping from a pre-crimp diameter to about the nominal or over inflated diameter of the balloon to which the scaffold will be crimped. An example of a partial crimping diameter is described by the scaffold diameter following “Stage II” in FIGS. 3A and 4A , and described in U.S. application Ser. No. 13/644,347 (docket no. 62571.675). A crimping mechanism or crimper may correspond to a linkage/mechanism including cooperating blades or teeth configured to apply an approximately uniform radial pressure on a scaffold to reduce its diameter to a final crimp diameter. The ratio of pre-crimp or intermediate crimp diameter to final crimped diameter may be greater than a ratio of expanded or post-dilation diameter (PDD) to the final crimped diameter of the scaffold. The crimping performed by the crimping mechanism may include a polymer material disposed between the teeth and surface of a scaffold; as example of such arrangement being found in US 2012/0042501 (attorney docket 62571.448).
[0065] “Recoil” means the response of a material following the plastic/inelastic deformation of the material and in the absence of externally applied forces, e.g., vessel contraction. When the scaffold is radially deformed well beyond its elastic range and the external pressure (e.g., a balloon pressure on the luminal surface) is removed the scaffold diameter will tend to revert back to its earlier state before the external pressure was applied. Thus, when a scaffold is radially expanded by applied balloon pressure and the balloon removed, the scaffold will tend to return towards the smaller diameter it had, i.e., crimped diameter, before balloon pressure was applied. A scaffold that has recoil of 10% within ½ hour following implantation and an expanded diameter of 6 mm has an acute post-dilation diameter of 5.4 mm. The recoil effect for balloon-expanded scaffolds can occur over a long period of time. Post-implant inspection of scaffolds shows that recoil can increase over a period of about one week following implantation. Unless stated otherwise, when reference is made to “recoil” it is meant to mean recoil along a radial direction (as opposed to axial or along longitudinal direction) of the scaffold.
[0066] “Acute Recoil” is defined as the percentage decrease in scaffold diameter within the first about ½ hour following implantation within a vessel.
[0067] “Axial” and “longitudinal” are used interchangeably and refer to a direction, orientation, or line that is parallel or substantially parallel to the central axis of a stent or the central axis of a tubular construct. The term “circumferential” refers to the direction along a circumference of the stent or tubular construct. Thus, a link spaced 180 degrees from another link means 180 degrees as measured about the circumference of the tubular construct.
[0068] “Radial” refers to a direction, orientation, or line that is perpendicular or substantially perpendicular to the central axis of the stent or the central axis of a tubular construct and is sometimes used to describe a circumferential property, i.e. radial strength.
[0069] A “stent” is a permanent structure, usually comprised of a metal or metal alloy, generally speaking, while a “scaffold” will refer to a structure comprising a bioresorbable polymer and capable of radially supporting a vessel for a limited period of time, e.g., 3, 6 or 12 months following implantation. It is understood, however, that the art sometimes uses the term “stent” when referring to either type of structure. Some material used to make a stent and/or scaffold structure is listed in U.S. Pat. No. 8,099,849.
[0070] “Radial strength” and “radial stiffness” adopts the definitions found in Ser. No. 13/842,547 filed Mar. 15, 2013 (attorney docket 104584.55).
[0071] A polymer scaffold according to a preferred embodiment is formed from a radially expanded or biaxially expanded extruded tube comprising PLLA. The degree of radial expansion (RE) and axial expansion (AE) that the polymer tube undergoes can characterize the degree of induced circumferential molecular and crystal orientation as well as strength in a circumferential direction. In some embodiments the RE is about 400% and the AE is 40-50%. Other embodiments of processing parameters, RE and AE expansions considered within the scope of the disclosure are found in U.S. application Ser. No. 13/840,257 filed Mar. 15, 2013 (Attorney Docket 104584.47).
[0072] The scaffold is laser cut from the expanded tube. The diameter of the tube is preferably selected to be about the same, or larger than the expanded diameter or PDD for the scaffold to provided desirable radial strength characteristics, as explained earlier. The scaffold is then crimped onto the balloon of the balloon catheter. Preferably, an iris-type crimping mechanism is used to crimp the scaffold to the balloon.
[0073] The pre-crimp memory in the scaffold material following crimping will induce some recoil when the scaffold is removed from the crimper. While a dwell period within the crimper can reduce this recoil tendency, there is residual recoil to restrain while the scaffold awaits use. This is done by placing a restraining sheath over the scaffold after the crimper blades are released and the scaffold removed from the crimper head. This need to reduce recoil is particularly evident when the diameter reduction during crimping is high, e.g., as in above examples, since for a larger starting diameter compared to the crimped diameter the crimped material can have higher recoil tendencies. Examples of polymers that may be used to construct sheaths described herein are Pebax, PTFE, polyethylene, polycarbonate, polyimide and nylon. Examples of restraining sheaths for polymer scaffold and methods for attaching and removing restraining sheaths for polymer scaffold are described in US20120109281, US20120324696 and U.S. Pat. No. 8,414,528, and U.S. application Ser. No. 13/708,638 (docket no. 62571.676).
[0074] FIGS. 1 and 1A show a side cross-sectional and front view, respectively, of a distal end of a scaffold-balloon catheter assembly 2 . The catheter assembly 2 includes a catheter shaft 4 and a scaffold 10 crimped to a delivery balloon 12 . As shown there are two separate sheaths 20 , 30 disposed over the scaffold 10 . The scaffold 10 is contained within a protecting sheath 20 and a constraining sheath 30 , which is placed over the outer surface of the protecting sheath 20 to position it over the scaffold 10 . Before inserting the catheter assembly 2 distal end within a patient, both the constraining sheath 30 and protecting sheath 20 are removed by a health professional. The protecting sheath has a distal end 20 b and a proximal end 20 a . The constraining sheath has a distal end 30 b and a proximal end 30 a.
[0075] The sheaths 20 , 30 provide an effective radial constraint for reducing recoil in the crimped scaffold 10 . Yet the sheaths 20 , 30 are also easily removed by a health professional at the time of a medical procedure by removing the outer sheath 30 from the inner sheath 20 . As described herein, a sheath that applies a radial constraint can be difficult to manually remove without adversely affecting the structural integrity of the medical device. In these cases, it is desirable to arrange the sheaths so that special handling is not required by the health professional when the sheath is manually removed. By making the sheath removal process easy to follow or intuitive, the possibility that a health professional will damage the medical device by improperly removing the sheath is reduced.
[0076] The constraint imposed by the sheaths 20 , 30 may be such as to maintain the scaffold 10 at essentially the same, or close to the same diameter it had when removed from the crimping mechanism. In some embodiments a first sheath, e.g., a polymer tube with weakened line and/or V-notch and configured for being torn when removed from the scaffold, is applied immediately after crimping and may apply a higher crimping force than the sheaths 30 and 20 . Preferred embodiments of such a sheath and process for applying the sheath to a crimped scaffold are described in U.S. application Ser. No. 13/708,638 (docket no. 62571.676). This first sheath is removed shortly after crimping, e.g., within ½ to one hour after crimping. Then sheaths 30 and 20 are applied. The sheath 30 is tightly fit over the sheath 20 and scaffold 10 so that the radial inward force applied on the scaffold 10 can prevent or reduce recoil in the scaffold 10 while the finished product is packaged and awaiting use. The health professional then removes both sheaths at the time of the medical procedure. As such, any potential recoil in the scaffold 10 prior to using the medical device is minimized. The sheath 30 , although imposing a tight fit on the scaffold 10 (through sheath 20 ), can be manually removed by a health professional such as by the technique illustrated in FIGS. 3 and 3A . This manner of removal, enabled by the construction of sheath 30 and 20 , avoids excessive longitudinal pulling forces that can result in damage to the scaffold, catheter, or dislodge the scaffold from the balloon. It also minimizes the overall length of the sheathed scaffold, which can be important for peripherally-implanted scaffolds, which can have lengths up to about 200 mm.
[0077] The inner sheath 20 and outer sheath 30 may alternatively be thought of as a protecting sheath 20 and constraining sheath 30 , respectively. When the scaffold 10 is constrained by sheath 30 , as in FIG. 1 , the constraining sheath 30 is located over the section of the protecting sheath 20 where the crimped scaffold 10 is found. This sheath 30 is made from a polymer tube material having a thickness and pre-stressed inner diameter size suitably chosen to cause the sheath 30 to apply a radially inward directed force on the scaffold 10 . The thicker the tube and/or the smaller the pre-stressed inner diameter size for the sheath 30 the higher this constraint will be on the scaffold 10 . However, the sheath 30 thickness should not be too thick, nor its inner diameter too small as this will make it difficult to remove the sheath 30 from the scaffold 10 . If excessive force is needed to reposition the sheath 30 , the scaffold 10 can dislodge from the balloon 12 or the scaffold 10 and catheter shaft 4 can become damaged when the sheath 30 is moved.
[0078] If only sheath 30 were applied, i.e., the sheath 20 is not present, the amount of preload that the sheath 30 could apply to the scaffold 10 without affecting scaffold-balloon engagement would be limited (pre-load refers to the sheath's ability to apply a radially compressive force on the scaffold or stent to minimize recoil and/or maintain the sheath over the scaffold during transport or handling). However, by introducing the protecting sheath 20 between the scaffold-balloon surface and sheath 30 the sheath 30 can impose a higher preload on the scaffold 10 without risk to the integrity of the scaffold-balloon engagement when the sheath 30 is applied to and/or removed from the scaffold 10 . The sheath 20 also protects a coating on the surface of the scaffold or stent while the sheath 30 is being removed. The protecting sheath 20 therefore serves to protect the integrity of the scaffold and/or scaffold-balloon structure as the sheath 30 is repositioned relative to the scaffold 10 . Examples of one-piece and two-piece sheaths capable of performing in a similar manner are found in US2012/0324696 (attorney docket 62571.498).
[0079] Again referring to FIGS. 1 , 1 A, 1 B and 1 C, the protecting sheath 20 extends over about the entire length of the scaffold (as shown) and may extend beyond the distal tip of the catheter assembly 2 . The protecting sheath 20 is preferably formed from a unitary piece of polymer material, which is shaped to protect the scaffold/balloon 10 / 12 . The protecting sheath may be configured as a two piece protecting sheath 20 having two separate portions 23 and 24 , as illustrated in FIG. 1B , or as a one-piece protecting sheath having a cut 26 defining separate halves 28 , 29 , as illustrated in FIG. 2 . In the case of a one-piece sheath, the cut 26 may begin at a proximal end 20 b at 26 a . There may be a weakened line 20 c to facilitate a tear away of the two halves 28 , 29 to separate one from the other, or there may be no weakened line from the start of the cut 26 to the distal end 20 b . The halves 29 , 28 are configured to freely move apart when the sheath 30 is positioned towards the distal end 20 b . In some embodiments, the location 26 a is a living hinge 26 a about which the upper half 29 and lower half 28 of the sheath 20 can rotate, or deflect away from the scaffold 10 when the sheath 30 is removed. The protecting sheath 20 prevents direct contact between the constraining sheath 30 and the surface of the scaffold 10 . After the sheath 30 is removed, the protecting sheath 20 is easily removed due to the presence of halves 23 , 24 or 28 and 29 , that preferably provide about no radial compressive force on the scaffold-balloon 10 / 12 , as compared to a cylindrical tube that must be slid across the balloon-scaffold when removed. Alternative embodiments of a two-piece protecting sheath are described in FIGS. 11-12 of US2012/0324696.
[0080] Referring once again to FIGS. 1 , 1 A, 1 B and 1 C there are views of the constraining sheath 30 portion of the sheath. The constraining sheath 30 circumscribes less than all of the sheath and balloon 10 / 12 when disposed over the scaffold 10 / 12 and protecting sheath 20 , as represented by the opening 50 . The sheath 30 is preferably configured in this way to jointly serve two conflicting objectives: (1) apply a radial compressive force on the scaffold 10 to minimize recoil, yet (2) be easily removed by a health professional in an intuitive manner, with reduced risk of causing damage to the scaffold or catheter (see FIG. 3 ) when the sheath 30 is removed.
[0081] Since the sheath 30 is not entirely cylindrically and only partially circumscribes the scaffold 10 (as can be appreciated from the views in FIGS. 1A , 1 B and 1 C) there is not a radial force applied directly by the sheath 30 about the entire circumference. However, it was found that objective (1) is met if the sheath 30 is combined with an inner protecting sheath 20 of appropriate thickness or radial stiffness. With such a matching, objective (1) could still be satisfied; that is, radial forces imposed by the scaffold 30 produces a sufficiently uniform radial constraint such that there is maintained a substantially a circular cross-section and limited recoil of the scaffold during a prolonged shelf-life for the medical device. For example, assuming both sheaths 20 , 30 are made from the same material, objective (1) may be met when sheath 20 is at least 20%, 30%, 40% or 50% less than the thickness of sheath 30 . This relative thickness will enable sheath 20 to effectively distribute the radial compressive load across the uncovered portion of the scaffold 10 , i.e., the opening 50 shown in FIGS. 1A and 1B . If the sheath 20 is too thin, then its radial stiffness is low and the radial compression loading does not distribute across the section of scaffold 10 exposed by the opening 50 . Additionally, it will be appreciated that the larger the opening 50 the more thick the sheath 20 should be, as the sheath 20 is called upon more to distribute the radial compressive loads across the opening 50 (so as to create the desired radial loading that limits recoil and maintains a circular cross section when opening 50 is increased in size).
[0082] In some embodiments the sheath 20 can have a minimum thickness of 100 microns or less than 100 microns, or 500 microns. The sheath 20 can have a thickness that is 5% of the sheath 30 thickness.
[0083] The amount less than the entire scaffold 10 circumscribed by sheath 30 , or the uncovered amount (e.g., as an arc length or % opening) will be referred to as opening 50 . As can be appreciated from FIG. 1B the opening 50 may be constant across the entire length of the constraining sheath 30 . With respect to objective (2) (above) the greater the opening 50 ( FIG. 1A ) the more easily the sheath 30 may be removed by, e.g., pinching it off the sheath 20 , as indicated in FIGS. 3 and 3A . However, the opening 50 cannot be too great as this might cause either the sheath 30 accidentally removed, or removed simultaneously with the sheath 30 , which might lead to damage to the scaffold, or result in the combined sheaths 20 , 30 not being capable of applying a sufficiently effective radial compressive force about the scaffold to minimize recoil and/or maintain about a circular crimped scaffold, i.e., no outward bulging of the uncovered scaffold portion as a result of unrestrained recoil.
[0084] Consistent with objectives, the sheath 30 should circumscribe more than 50%, but less than the entire scaffold 10 , to facilitate removal from sheath 20 without disturbing the relationship between the sheath 20 /scaffold 10 . Opening 50 therefore spans an arc-length less than about 180 degrees. In other aspects, the sheath 30 may circumscribe more than 50%, 55%, 60%, 65%, 70% or 80%, but not the entire scaffold 10 ; the opening 50 may span about 3%, 6%, 8%, 11%, 13%, 17%, 19%, 22%, 25%, 31%, 33% or 42% of the entire circumference of the scaffold 10 ; or the opening 50 (expressed as an arc length) may be about 20-50, 80-120, 10, 20, 30, 50, 70, 90, or 110 Deg.
[0085] According to another aspect, in keeping with objectives (1) and (2), when fully assembled the sheaths, 20 , 30 are preferably arranged so that an entire one of the portions 23 , 24 or halves 28 , 29 are fully covered by the sheath 30 and the other only partially covered by the sheath 30 , or the seam 27 (separating portion 23 and 24 ) or cut 26 (separating halves 28 , 29 ) are never within the opening 50 or uncovered by the sheath 30 . This arrangement is shown in FIG. 1A . In this preferred embodiment the portion 23 is fully covered and the portion 24 partially covered by the sheath 30 , or nowhere is seam 27 within the opening 50 . By this arrangement, the pinching process ( FIG. 3 , 3 A) can best preclude both sheaths 20 , 30 being (unintentionally) removed simultaneously, which is not preferred although acceptable in some embodiments. If, in contrast, the seam 27 were located within the opening 50 (e.g., seams 27 were located 90 degrees from the position shown in FIG. 1A ), then a pinching and lifting up of the sheath 30 of the sheath 30 ( FIG. 3A ) might also remove the sheath 20 . If both sheaths 20 , 30 are removed simultaneously then there may be damage to the scaffold 10 because the pinching of the fingers ( FIGS. 3 , 3 A) in combination with the sheath 30 removal would cause the sheath 20 to pull across the surface of the scaffold 10 and/or balloon 12 surface.
[0086] In an alternative embodiment sheath 20 and 30 may be removed simultaneously. In one example this may be achieved by placing the seam 27 within the opening 50 . Additionally, the opening may span a relatively small angle to cause both sheaths 20 , 30 to be removed at the same time. For example the angle may be about 5, or 15 degrees. Thus, for a seam within the opening 50 and/or the angle about 5, 10, 15, or between 5 and 20 degrees a pinching or peeling away of the sheath 30 will also pinch or peel away sheath 20 .
[0087] According to another aspect of the disclosure, a constraining sheath may have an opening 50 , a non-circular outer surface to facilitate a peeling-away or pinching of the constraining sheath to remove the constraining sheath from the protecting sheath, and/or a notch intended to cause buckling or kinking of the sheath, thereby causing it to suddenly lose transverse stiffness when the sheath 30 edges defining the opening 50 are pinched together or pulled apart. All these features are intended to facilitate an easier removal of a constraining sheath from a protecting sheath in the manner shown in FIGS. 3-3A .
[0088] FIGS. 4A-4C illustrate a constraining sheath 60 having the opening 50 (as in the case of sheath 30 ), the notch and non-circular outer surface features. A constraining sheath according to embodiments may include the opening 50 and a notch, the opening and a non-circular outer surface, or a combination of all three features as in the illustrated embodiment.
[0089] In one embodiment, the non-circular surface for the sheath 60 includes ridges 62 a , 62 b , 64 a , 64 b . The sheath 60 also includes a notch 61 formed on the outer surface, inner surface or both outer and inner surfaces at about the location shown, which separates a first portion 60 a and second portion 60 b of sheath 60 . Portions 60 a and 60 b are symmetric about an axis passing through the notch 61 and center of the scaffold-balloon 10 / 12 in FIG. 4A . As can be appreciated from the substantially reduced thickness at the notch 61 compared to other portions of the sheath 60 , the notch 61 facilitates a folding, kinking or buckling of the sheath 60 at the notch 61 when the sheath 60 is removed from the sheath 20 in the manner shown in FIG. 3A . This can impose less difficulty on the health professional removing the sheath 30 , because when the sheath 60 buckles at the notch 61 there is less resistance to deformation by the sheath 60 when the edges are pinched together ( FIG. 3A ) or pulled apart.
[0090] Referring again to FIGS. 4A-4C , portion 60 a of the sheath 60 , as in the case of portion 60 b , has two longitudinally-running ridges 64 a , 64 b . Preferably these ridges 64 a , 64 b form a concave surface 65 a , in contrast to the convex outer surface of sheath 30 (or the portion of sheath 60 outer surface exclusive of concave surfaces 65 a , 65 b ). Similarly, portion 60 b has ridges 62 a , 62 b and concave surface 65 b . The concave surfaces 65 a , 65 b , which may each have a circumferential extent about the average width of a fingertip, provides a surface that engages the fingertip to facilitate sheath 60 removal from the scaffold. Alternatively, a pair of the ridges 62 , 64 may be engaged (one with each finger) to lift the sheath 60 off of the sheath 20 .
[0091] In alternative embodiments include, in any combination: ridges pairs 62 and 64 may extend only partially or over a portion of the sheath 60 , such as two pair (symmetrically disposed about the axis passing through the notch 61 and center of the scaffold 10 ) or all four of the ridges 62 , 64 being located only at about the distal end of the sheath 60 ; the notch 61 being located only at about the distal end; and the surfaces 65 a , 65 b being convex as opposed to concave as shown.
[0092] The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize.
[0093] These modifications can be made to the invention in light of the above detailed description. The terms used in the claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the claims, which are to be construed in accordance with established doctrines of claim interpretation. | A sheath is placed over a crimped scaffold to reduce recoil of the crimped polymer scaffold and maintain scaffold-balloon engagement relied on to hold the scaffold to the balloon when the scaffold is being delivered to a target in a body. The sheath has an opening spanning the length of the sheath. The opening spans an arc length of about 90 degrees with respect to the circumference of the scaffold or balloon. The sheath may be removed from the scaffold by pinching the sheath between a thumb and forefinger, or bending or peeling back the sheath from the edges of the opening using fingertips. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to voltage driver circuits and, in particular, to an improved voltage driver circuit for driving n-channel MOS RAMs in a data processing system.
2. Description of the Prior Art
In recent years, data processing systems have been evolving towards more efficient and more compact units. This trend has been paralleled by the development of systems which operate at ever-increasing speeds. Typifying these trends is the development and success of mini-computers.
An essential component of a data processing system is the memory unit. Random access memories (RAMs) have recently evolved from p-channel devices to n-channel metal-oxide semiconductor field effect transistors (MOSFETs). This development has numerous advantages. Where the typical p-channel device, such as an Intel 1103, would contain 1,024 (or approximately 1K) memory locations per bit, an n-channel MOSFET, such as a TMS 4030, contains 4,096 (or approximately 4K) memory locations per bit. In addition, the n-channel device is capable of operating at faster speeds. Both the increased density and speed of the n-channel devices make them clearly more desirable for modern data processing and mini-computer usage. Unfortunately, the development of improved RAMs has significantly preceded the development of appropriate driver circuits for operating these RAMs.
P-channel RAMs typically require operation in a memory system environment which has available three positive power supplies or three system levels of power (5V, 12V and 15-20V). N-channel systems typically have only two positive power supplies available (5V and 12V and a third supply at -3V to -5V). In addition, n-channel RAMs are particularly sensitive to input voltage levels and rise times of clock signals coupled to the chip enable input terminals.
Commonly used for driving the RAMs is a standard off-the-shelf quad TTL to MOS clock driver circuit. (Such a circuit is commonly produced by integrated circuit manufacturers, such as the SN75365 by Texas Instruments.) However, the circuit was originally designed for driving p-channel memory devices. Its use in an n-channel environment presents several difficulties. If only the two commonly available (5 volt and 12 volt) system-level power supplies are used, the peak voltage level and rise time parameters will be unacceptable for properly driving n-channel RAMs. Prior art remedies to this deficiency required supplying a third high-level voltage (greater than 12 volts) to the driver circuit. This, however, is a costly solution, in terms of dollars as well as in space and weight.
Another method of remedying this problem is to increase the high level (12 volt) system voltage presently available in the RAM environment. The increased voltage may then be stepped down to 12 volts, thereby effectively providing three voltage levels for use by the driver circuit. However, increasing the voltage necessitates both alteration of the system as well as increased power requirements.
OBJECTS OF THE INVENTION
It is an object of the present invention, therefore, to provide an improved voltage driver circuit.
It is another object of the present invention to provide an improved voltage driver circuit which requires only 5 volt and 12 volt system level voltages for its proper operation.
It is another object of the present invention to provide an improved apparatus which utilizes available system level power supplies, said apparatus providing an output voltage signal within the desired parameters for a driving n-channel MOS RAM.
It is still yet another object of the present invention to provide an apparatus for driving n-channel RAMs which does not require alteration of the system-level voltages within the RAM environment for proper operation of the memory system.
Other objects and benefits will become apparent from the following description of the preferred embodiment of the invention when read in conjunction with the drawings contained herewith.
SUMMARY OF THE INVENTION
Voltage clock driver circuits are readily available to computer manufacturers from conventional supply sources. However, such circuits do not provide output signals within acceptable parameters for driving n-channel RAMs. This is due to the lack of a third high-level (15-18 volt) power supply within the RAM environment. The present invention improves upon available voltage driver circuits so as to provide a new apparatus which generates signals within the desired parameters. An available system voltage (12V) is supplied to a first power terminal of the driver circuit. An inductor is connected from said first power terminal to a second power terminal of the circuit. The inductor causes the second power terminal to reach a significantly higher voltage level within the desired time parameters. In this manner, the output voltage of the driver circuit achieves the desired characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of output voltages from voltage driver circuits.
FIG. 2 is a schematic diagram of a generalized prior art voltage driver circuit.
FIG. 3 is a schematic diagram of a voltage driver circuit according to the invention.
FIG. 4 is a diagram of the effective V 3 , voltage in a voltage driver circuit according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, output voltage E out of a frequency driver circuit is plotted against time under various conditions. (The time scale is in nano-seconds). Curve 10 shows an ideal output voltage for driving n-channel RAMs. It rises relatively rapidly (within 20 nano-seconds) and achieves a peak voltage (12 volts) within a short, acceptable time frame. Curve 11 illustrates the output voltage which is obtained from a prior art driver circuit, such as an SN75365, when a 12-volt power supply is attached to both the V 2 and V 3 terminals. Rise time to achieve peak voltage (approximately 100 nano-seconds to reach 90 % of peak voltage) is not within critical limits for proper driving of n-channel RAMs.
Referring now to FIG. 2, a generalized prior art voltage circuit is shown. (Such a prior art circuit is commonly available on an integrated circuit (IC) chip supplied by conventional manufacturers).
Gate 20 may be an AND, NAND, OR, or NOR gate which may be comprised of an electronic circuit configuration of any of the following types: DTL, TTL, ECL or CML. Gate 20 is driven by the low-level system voltage V 1 (5V) applied through power terminal 21. Gate 20 has input terminal 22 for input signal E IN . E IN is a voltage signal which is measured as the potential difference between terminal 22 and common ground 23. Gate 20 also has output terminal 24 which is coupled to the base of transistor 27 and, by resistor 37, to the emitter of transistor 27. The emitter of transistor 27 is coupled to the base of transistor 28 and, by resistor 38, to the common ground 23. The emitter of transistor 28 is connected to the common ground 23 and may also be considered as output terminal 49. The collector of transistor 28 is connected to output terminal 48. The potential difference between output terminals 48, 49 is E out .
The "upper" stage of the circuit, conventionally referred to as a "totem pole" stage, is comprised of the following components. Input voltage terminal V 3 is coupled by resistor 39 to both the base of transistor 29 and the collector of transistor 27. Input voltage terminal V 2 is also coupled to the collectors of transistors 29 and 30. The emitter of transistor 29 is coupled to the base of transistor 30. Resistor 40 couples the emitter of transistor 29 to the emitter of transistor 30. The emitter of transistor 30 is coupled to the collector of transistor 28. The high level system voltage (of approximately 12 volts) is attached to the V 2 terminal. (The RAM load, which may be comprised of TMS 4030 RAMs, is represented as an effective capacitive load. Typically a plurality of RAMs are connected in parallel by a main bus to a voltage driver circuit and have the loading effect of appearing as a 390 picoFarad load to the voltage driver circuit.) The output voltage E out from the prior art circuit is as shown in Curve 11 in FIG. 1, which is deficient for driving n-channel RAM loads. The reason for achieving output Curve 11 lies in the operation of the prior art circuit.
Referring again to FIG. 2, when Gate 20 is on, current flows through into the base of "phase splitter" transistor 27 and saturates it, which causes transistor 27 to look like a closed switch. This in turn causes current to flow through the emitter of transistor 27 into the base of transistor 28 and similarly saturates transistor 28. This corresponds to a closed state for "switch" 28 with its collector to emitter voltage very small. This is equivalent to the low output voltage volt for the voltage driver circuit. A low output has a maximum of 0.3 volts.
When Gate 20 is off, transistors 27 and 28 are similarly off. This corresponds to the "on" state of the circuit and must be described in conjunction with the upper "totem pole" stage of the circuit. With phase-splitter transistor 27 off, current flows into the base of transistor 29, causing it to be on. This in turn causes transistor 30 to be on, and the output voltage E out to be high. However, V 3 of 12 volts is not high enough to saturate transistors 29 and 30. In particular, the collector to emitter voltage of transistor 30 is approximately 1 volt. Consequently, although the output voltage E out is high, it is approximately one volt lower than V 2 (or approximately 11.0 volts). To remedy this problem requires a higher V 3 which would cause a complete saturation of transistor 30 with a collector to emitter voltage of only a maximum of about 0.3 volts.
Referring now to FIG. 3, a circuit according to the invention is shown connected to an effective capacitive load, which is typical of how a plurality of RAMs connected in parallel appear to their voltage driver circuit. Gate 60 may be an AND, NAND, or NOR gate which may be comprised of an electronic circuit configuration of any of the following types: DTL, TTL, ECL, or CML. Gate 60 is driven by the low-level system voltage V 1 , (5V) applied through power terminal 61. Gate 60 may have a plurality of input terminals. One of these, terminal 62, is for input signal E IN which is considered the primary drive signal for Gate 60. E IN is a voltage signal which is measured as the potential difference between terminal 62 and common ground 64. There may be additional input signals which are considered enabling signals for gate 60. In FIG. 3 only a single enabling signal terminal 63 is shown. Gate 60 also has output terminal 65 which is coupled to the base of transistor 71. The emitter of transistor 71 is coupled by resistor 66 to common ground 64 and by resistor 69 to its base. The emitter of transistor 71 is also coupled to the base of transistor 72. The collector of transistor 72 is coupled to the collector of transistor 71 by two forward-biased diodes 75, 76 connected in series between said collectors. The emitter of transistor 72 is coupled to common ground 64 and is also considered output terminal 79. The collector of transistor 72 is coupled to output terminal 78. The potential difference between output terminals 78, 79 is E out ' .
The "totem pole" stage of the circuit is designed as follows. A V 3 ' point is coupled by resistor 67 to the base of transistor 73 and to the collector of transistor 71. A V 2 terminal is coupled to the collectors of transistors 73 and 74. The emitter of transistor 73 is coupled to the base of transistor 74 and, by resistor 68, to the emitter of transistor 74. The emitter of transistor 73 is also coupled to a point between diodes 75, 76. The emitter of transistor 74 is also coupled to the collector of transistor 72. Finally, an inductor 70 couples the V 2 terminal to the V 3 ' point.
(Additionally, a diode may be connected from the emitter to the collector of transistor 74. In this manner, the circuit shown in FIG. 3, with the exception of inductor 70, corresponds to a conventional driver circuit such as a SN75365 by Texas Instruments.)
For discrete circuits, transistors 71 to 74 may have beta-values of 50, such as a 2N2270. For IC circuits, transistors 71 to 74 may have beta-values of 10. Diodes 75, 76 may be any small signal diode, such as an 1N903. Resistors 66, 67, 68, 69 may have the following OHM values respectively: 250, 6K, 250, 200. All of these above values are within a range of workable values, as one ordinarily skilled in the art will readily recognize and substitution of alternative values or equivalent components is foreseen. The above-mentioned values are given as suggested values and in no way limit the scope of the invention.
Operation of the circuit according to the invention is as follows. The high-level (12-volt) system voltage is coupled to the V 2 terminal. No power source is coupled to the V 3 point (or terminal). The operating characteristics of the output voltage E out ' are shown as Curve 12 in FIG. 1. E out in Curve 12 exceeds the required minimum voltage of 12 volts for a short duration, but this is of no consequence. The critical factor is achieving a minimum E out of 12 volts. The key to the difference between output Curves 11 and 12 of FIG. 1 lies in the operation of inductor 70 of FIG. 3.
Empirical testing of voltage driver circuits, such as those shown in FIGS. 2 and 3, has revealed that to obtain a desirable E out or E out ' curve, the voltage at the V 3 or V 3 ' point must be at least 15 volts at the time of switching of phase-splitter transistor 27 of FIG. 2 or phase-splitter transistor 71 of FIG. 3, from an on to an off state. An inductor operates on the basis of changing current. In this manner, it is a dynamic element within the circuit configuration only when the current passing through it changes, either from high to low, or from low to high. Therefore, in the circuit shown in FIG. 3, inductor 70 is of importance only when transistor 71 changes state, which is precisely the time that additional V 3 ' voltage is needed. The effect of inductor 70 is a coupling of the V 3 ' voltage to the changing of the dynamic condition of transistor 71. When transistor 71 goes off, V 3 ' receives a "kick". This effect diminishes soon after the change. Nonetheless, this kick is sufficient to obtain an output voltage corresponding to Curve 12 of FIG. 1. (The corresponding "negative kick" to V 3 ' is of no consequence to the operation of the circuit).
Referring now to FIG. 4, E IN and V 3 ' voltages of FIG. 3 are plotted in parallel. It should be noted that E IN can be considered an enabling signal for gate 60 and the controlling signal for the operation of the driver circuits. As can be seen starting with E IN in a high, steady state of 5 volts, V 3 ' is equal to 12 volts. When E IN changes to a low state, V 3 ' is "kicked" by approximately 6 volts and then returns to 12 volts. (The pulse width of E IN is assumed to be greater than 250 nano-seconds). Referring once again to FIG. 1, Curve 12 shows the resulting output voltage E out . In Curve 12, E out achieves the required minimum output voltage within a desired time parameter.
The circuit according to the invention is used for TTL (or DTL, ECL or CML) to MOS conversion. This is an important requirement for driving RAMs which appear as effective capacitive loads to the voltage driver circuits. It can be seen that the invention can be embodied by a relatively simple modification to a standard off-the-shelf voltage driver circuit which has a third power terminal externally available. An SN75365 made by Texas Instruments contains four such voltage driver circuits on a single IC chip.
Terminals for receiving input drive voltages V 1 , V 2 , and V 3 are externally available on the chip, and they are commonly connected to a plurality of driver circuits internally within the driver chip by the manufacturer. (Similarly, all but one of the input enabling terminals for each of the four circuits are commonly connected, and there is also a common ground for the four circuits.) By externally coupling an appropriate inductor between the V 2 and V 3 terminals, a plurality (which in the above-mentioned chip is four) of voltage driver circuits with desirable output characteristics is obtained. It should be noted that in this manner, only one inductor is required for modification of all driver circuits contained in any one IC chip. The suggested range of inductive values for the inductor is between 36 and 100 microhenries for a pulse width of 500 nano-seconds and repetition rates of 1.0 microhenries or less. This modification is both simple to achieve and inexpensive. It is believed to have widespread application within the computer industry due to the trending towards n-channel MOS RAMs. | An apparatus is disclosed which comprises an improved voltage driver circuit. Commonly available voltage driver circuits are deficient for driving n-channel MOS RAMs due to insufficient peak voltage and extended rise time. The apparatus, without requiring an additional voltage power supply or modifications to the memory system environment, effectively increases an internal drive voltage which results in the desired performance characteristics for driver circuits. | 7 |
FIELD OF INVENTION
[0001] This invention relates to an apparatus and method for vacuum collection of debris, such as leaves. In particular, this invention relates to a collector which maintains cleanliness in the area surrounding the device by controlling the discharge of fine particulate exhaust.
[0002] BACKGROUND OF THE INVENTION
[0003] Heretofore, vacuum leaf collection equipment has been manufactured and known in the art. Traditional designs of vacuum leaf collectors/loaders employ a large-diameter impeller, driven from a large gas or diesel engine. The impeller pulls a large volume of air through a vacuum hose or other attachment used to collect leaves. The leaves that travel through the impeller are reduced in size and broken apart, many pulverized into very small particles. Leaves are exhausted from the leaf collector into a leaf collector box.
[0004] Collector boxes have been designed with enclosed sides and a screened roof. The screened roof retains the leaves within the collector box, but lets air escape through the screening. Due to the large volume of exhausting air, fine leaf particles are also entrained in the air and pass through the screening. These particles go into the atmosphere above the leaf collector box, creating clouds of dust and particles that fall on operators, equipment, and parked cars. Depending on wind conditions, the dust may be carried to surrounding houses and other property in the area. The resulting operation is very dirty, especially if the leaves are dry and brittle. Operators sometimes will wear dust masks, hoods, and eye protection against the dust. None of the related devices have adequately addressed this problem. No invention to date has solved the problem of dirty exhaust from leaf collectors.
SUMMARY OF THE INVENTION
[0005] According to the present invention, the foregoing and other objects and advantages are attained. The present invention relates to a vacuum apparatus and method for collecting debris, such as leaves, litter, grass clippings, and other types of yard waste, in a way that minimizes exhaust of fine particulate debris and leaf matter, maintains cleanliness of the area in the vicinity of the operating equipment, and improves the cleanliness condition for the workers who operate the equipment.
[0006] A first general aspect of the invention provides an apparatus for collection of debris comprising a vacuum device; a collector operatively attached to the vacuum device; and a discharge opening positioned on one of a bottom and a side of the collector.
[0007] A second general aspect of the invention provides an apparatus for collection of debris comprising a vacuum device; an airstream for carrying debris from the vacuum device; a tank of fluid; at least one inlet for injecting a fluid from said tank of fluid onto said debris within the airstream; and a collector operatively attached to receive said airstream.
[0008] A third general aspect of the invention provides an apparatus for the collection of leaves and fine leaf particulate comprising a vacuum device for vacuuming said leaves into an airstream; a collector operatively attached to the vacuum device through a discharge chute; a fluid injection system for wetting the leaves and fine leaf particulate within said discharge chute; a filter separating the collector into a first volume and a second volume; two screened walls forming said filter wherein each screened wall is located parallel to and inboard a sidewall of the collector and further each screened wall runs vertically from the floor to the solid roof and horizontally from the forward wall to the rear wall; a lower wall section of solid construction comprising approximately the lower one-third of the screened wall; an upper wall section of screen mesh comprising the upper two-thirds of the screened wall; and a plurality of openings in the floor of the collector beneath the second volume.
[0009] A fourth general aspect of the invention comprises a method for collection of debris comprising partitioning, with a filter, a collector into a first volume and a second volume; vacuuming the debris with a vacuum device into an airstream; discharging the airstream containing the debris into the first volume of the collector; collecting the debris due to gravity and impingement within the first volume of the collector; filtering the debris from the airstream with the filter further causing the debris to collect within the first volume of the collector; and exhausting the filtered air stream through at least one opening in a side or bottom surface of the second volume.
[0010] A fifth general aspect of the invention comprises a method for containing the residual debris of a filtered air stream from a collector comprising locating at least one exhaust path from the collector on least one of the floor or side of the collector to direct said filtered air stream to a particulate collection device for the residual debris; positioning a removably attachable particulate collection device proximate to said exhaust path from the collector; collecting said residual debris in said particulate collection device during intake and collection of said debris; and emptying and replacing said containment device when full with said residual debris.
[0011] A sixth general aspect of the invention further comprises a method for collection of debris comprising vacuuming the debris with a vacuum device into an airstream; storing a fluid in a tank; injecting the fluid from said tank to wet a fine particulate debris within the airstream; discharging said debris into a collector; collecting said debris within said collector; and further collecting said fine particulate debris by gravity and by impingement within said collector.
[0012] These and other aspects, advantages and salient features of the invention will become apparent from the following detailed description, which, when taken in conjunction with the annexed drawings, where like parts are designated by like reference characters throughout the drawings, disclose embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Some of the embodiments of this invention will be described in detail, with reference to the following figures, wherein like designations denote like members wherein:
[0013] [0013]FIG. 1 illustrates a side view of an embodiment of a vacuum leaf collection apparatus in accordance with the present invention;
[0014] [0014]FIG. 2 illustrates a top sectional view of an embodiment of the collector in accordance with the present invention;
[0015] [0015]FIG. 3 illustrates a top sectional view at floor level of the collector in accordance with the present invention;
[0016] [0016]FIG. 4 illustrates a side sectional view of the collector showing the screened wall and support members within a collector in accordance with the present invention;
[0017] [0017]FIG. 5 illustrates a side view an alternate embodiment of a vacuum leaf collection apparatus including mounting of a dust collection bag system in the exhaust air discharge path beneath the collector in accordance with the present invention; and
[0018] [0018]FIG. 6 illustrates the mounting of a fluid tank, pump, piping, and spray inlets for injection of a fluid into the discharge of a vacuum device for a leaf collection apparatus in accordance with the present invention.
DETAILED DESCRIPTION
[0019] Although certain embodiments of the present invention will be shown and described in detail, it should be understood that various changes and modification may be made without departing from the scope of the claims. The scope of the present invention will in no way be limited to the number of consulting components, the material thereof, the shapes thereof, the relative arrangement thereof, etc., and are disclosed simply as an example of an embodiment. Although the drawings are intended to illustrate the present invention, the drawings are not necessarily drawn to scale.
[0020] Referring to FIG. 1, a leaf collection apparatus, hereinafter referred to as 10 is shown, which may include a vacuum device 15 , a discharge device 20 , and a collector 55 . The vacuum device 15 may be an apparatus such as fan, vacuum pump, or large diameter impeller. The vacuum device 15 , the discharge device 20 , and the collector 55 may be mounted on a trailer, such as trailer 45 . The apparatus 10 may also be mounted on a cab and chassis (not shown). Several alternative embodiments may exist whereby the collector 55 may be permanently mounted on its own trailer 45 or may be chassis mounted (not shown).
[0021] The vacuum device 15 may include a large diameter impeller 35 contained within an impeller housing 40 . Rotation of the impeller 35 establishes suction on the intake side of the impeller housing 40 . A suction hose 30 or similar conduit directs debris, such as leaves, collected off the ground by a suction head 25 to the impeller 35 . Any suitable type of drive device, such as a gasoline or diesel engine (not shown), may be coupled to and power the impeller 35 . Debris and leaves are sucked off the ground into an airstream 17 created by the vacuum device 15 . The airstream 17 within the various figures will be represented by double arrows. The debris and leaves within the airstream 17 passing through the impeller housing 40 may be chopped up by action of the impeller 35 thereby creating, in part, small particles of debris, leaf sections and fine particulate of leaf dust. Whole leaves, leaf sections, and leaf dust are discharged from the impeller housing 40 and carried within the airstream 17 through the discharge device 20 comprising many possible chute or tube arrangements to convey the leaves to the collector 55 . One embodiment utilizes a path from the impeller housing 40 through a discharge chute 50 , which is flexible and extended, directly discharging into the collector 55 . A rubber boot-type sealing device 70 or other similar seal prevents leakage of fine leaf particulate to the ambient air outside, at the juncture of the impeller housing 40 and the discharge chute 50 .
[0022] Referring again to FIG. 1, an embodiment of the collector 55 is a rectangular box of steel construction with substantially solid walls. The collector has sides, a top, and a bottom. The sides are defined by both a front and rear, and the two sidewalls. The forward wall 75 , or front, of collector 55 , closest to the vacuum device 15 , is penetrated by the discharge chute 50 to accept leaf discharge. The top surface, or top, of the collector 55 is a solid roof 80 that prevents exhaust of fine leaf particulate to the outside atmosphere above collector 55 . The rear surface, or rear, of the collector 55 is of substantially solid construction, consisting of a hinged rear door 85 pivoting on hinges 90 . Sidewalls 95 and a floor 100 , or bottom, are also of substantially solid construction. Wall support members 105 may be provided to provide structural strength to the forward wall 75 , the hinged rear door 85 , the sidewalls 95 , and the solid roof 80 to contain the debris load or the air pressure that builds up within collector 55 . Floor support members 107 provide support from below for the floor 100 and the overall weight of the collector 55 . The collector 55 may be disposed on the trailer 45 with a dumping mechanism, such as a hydraulic lift, (not shown) that raises and lowers the forward end of collector 55 such that the leaf contents empty, by gravity, through hinged rear door 85 .
[0023] Referring to FIG. 2, which shows a top sectional view of the collector 55 , one alternative embodiment may include a receiving chute 50 . The receiving chute 50 is mounted to the collector 55 such that the exhaust end of the receiver chute 50 penetrates the collector 55 . Again referring to FIG. 2, the internal volume of the collector 55 is divided into a first volume 60 and a second volume 65 by screened walls 115 . The screened walls 115 may comprise various configurations internal to collector 55 . In one embodiment, the screened walls 115 may extend the length of the collector 55 from the forward wall 75 to the hinged rear door 85 . Vertically, the screened walls 115 may extend from the floor 100 to the solid roof 80 . One screened wall 115 may be located inboard of and parallel to each sidewall 95 , separated from the sidewall 95 by the wall support members 105 . The first volume 60 is the main space of collector 55 , bounded by the solid roof 80 , the floor 100 , the forward wall 75 , the hinged rear door 85 and the screened walls 115 . The second volume 65 of the collector 55 includes all of the individual spaces between the screened walls 115 and sidewalls 95 and bounded by the solid roof 80 above, the floor 100 below, and separated from each other by the wall support members 105 .
[0024] Referring to FIG. 3, the floor 100 forms the bottom surface of collector 55 between the screened walls 115 , the forward wall 75 , and the rear hinged door 85 . The floor openings 110 provide a path to exhaust the filtered airstream 17 from the second volume 65 of the collector 55 .
[0025] Referring to FIG. 4, the screened walls 115 may include a lower wall section 120 of substantially solid material construction, such as steel, and an upper wall section 125 that includes a screen mesh 130 . The lower wall section 120 includes approximately one-third of the height of the collector 55 and the upper wall section 125 includes the remaining approximately two-thirds of the height. The screen mesh 130 of upper wall section 125 has openings in the mesh sized to retain large leaf sections within the first volume 60 of the collector 55 , but to allow fine leaf particulate and leaf dust in the airstream 17 to pass through to the second volume 65 without clogging. The lower wall section 120 provides structural strength to the screened wall 115 in order to support the leaves that accumulate in the first volume 60 and also to hold any force that builds up as a result of pressure drop across the screened walls 115 . Wall support members 105 provide backing support for the screen mesh 130 . Depending on the specific opening size of the screen mesh 130 , additional support to the screen mesh 130 may be provided by screen support members 133 operatively attached between wall support members 105 .
[0026] Debris and leaves carried within the airstream 17 exiting from vacuum device 15 pass through discharge device 20 into collector 55 . The larger and heavier pieces of debris and leaves drop to the floor 100 of collector 55 by gravity directly or after colliding with the forward wall 75 , solid roof 80 , hinged rear door 85 , or the screened walls 115 of the collector 55 , losing energy in the collision and then falling to the floor 100 . The screened walls 115 act as a filter, retaining the larger pieces of debris and leaves exhausted from discharge device 20 into collector 55 within the first volume 60 , but permitting some fine debris, fine leaf particulate, and dust within the airstream to pass through to the second volume 65 , along with the airstream 17 . After the airstream 17 passes through the screen mesh 130 of upper wall section 125 , the airstream hits the sidewalls 95 and is forced down to a plurality of floor cutouts 110 in the floor 100 of collector 55 . Fine debris, fine leaf particulate and dust that passes through the floor cutouts 110 exhausts downward below the collector 55 . An alternative arrangement may permit the airstream 17 exhaust from the collector 55 through various openings (not shown) on the sidewalls 95 of the collector 55 or in other portions of the sides of the collector 15 .
[0027] The floor 100 of the collector 55 is substantially solid with structural support provided by a plurality of floor supports members 107 located below. Exhaust paths for leaf particulate and airstream 17 from the second volume 65 are provided through floor cutouts 110 of the floor surface between screened walls 115 and sidewalls 95 and between adjacent floor support members 107 . The airstream 17 entraining fine leaf particulate, exhausting through floor cutouts 110 , is directed downward to the ground directly beneath the collector 55 . Leaf particulate falls towards the ground and thus will tend to collect at the ground location, or immediate vicinity, where it hits or falls rather than rising and going in the atmosphere. Because the leaf particulate is not exhausted through the solid roof 80 to the airspace well above the ground, drift of the leaf particulate is minimized and the amount of dust falling on surrounding areas is limited. Exhaust of the airstream from beneath the collector 55 will also be below the head and face of the operators. Exhaust at a lower height and less drift of particulate also provides a cleaner work environment for the operators and lessens the need for hoods and other protective equipment. The settling of leaf particulate in a relatively limited area under and around the leaf collector apparatus 10 makes it easier for the operators of the equipment to clean the area after leaf collection is complete.
[0028] An alternate embodiment of the invention, as shown in FIG. 5 may further include one or more particulate collection devices mounted beneath the collector 55 . The airstream 17 entraining leaf particulate from second volume 65 of collector 55 is exhausted in a downward direction through floor cutouts 115 . The exhaust air hits the particulate collection devices and the entrained leaf particulate will tend to fall out. The airstream 17 is exhausted from openings in the particulate collection device 134 to the ground below. The particulate collection devices may be removably attached to the collector 55 with bolting, screwing, hanging on hooks and other suitable means to permit removal for emptying or maintenance, and subsequent restoration or replacement. In one embodiment, the particulate collection devices may be dust bags 135 . The airstream 17 passes out of the collection device 134 to the ground below where leaf particulate will further tend to drop out. The collection devices enhance cleanliness by: 1) reducing the leaf particulate drifting surrounding the leaf collecting apparatus, 2) reducing the dust reaching the operators, and 3) minimizing the need for cleanup after leaf collection.
[0029] With a traditional design, (i.e., an impeller driven from engine exhausting large volumes of air) dry leaves create much more dust than do leaves that are wet from rain. However, wet leaves are heavier than dry leaves. Wet leaves are more difficult to vacuum off the ground and put more load on the impeller 35 and the engine (not shown) due to their greater weight. Wet leaves will also stick to the impeller 35 and the inside of the impeller housing 40 . Collection of wet leaves improves the environmental conditions surrounding the leaf loader, but can slow down the collection process. Injecting a fluid into the discharge air and coating the leaves and debris with fluid after they have passed through the impeller 35 results in dust control without loading the impeller 35 and engine (not shown) with the extra weight of wet leaves and without fouling the suction hose 30 .
[0030] Referring to FIG. 6, a further embodiment of the invention may additionally mount a fluid injection apparatus 200 on the leaf collection apparatus 10 . The fluid injection apparatus 200 includes a tank of fluid 220 , a fluid pump 225 , a hose 230 , and at least one inlet 240 . In one embodiment, a plurality of inlets 240 may be operatively attached to the discharge chute 50 with a symmetrical arrangement with respect to the airstream 17 between the impeller housing 40 and the collector 55 . The inlets 240 may be comprised of nozzles, injectors, orifices, or other devices capable of injecting the fluid in the form of a spray that can evenly wet the fine particulate matter entrained in the airstream 17 . The symmetrical arrangement of the inlets 240 around the airstream 17 of discharge device 20 provides for uniform wetting of the fine particulate matter in the airstream 17 .
[0031] The fluid spray from the inlets 240 may be applied to the leaves as they pass through the discharge device 20 . The fluid-coated leaf particles become heavy and tend to drop out more effectively in collector 55 . Any fluid that is sprayable, that will coat the fine debris particulate, and that is environmentally benign may be employed. In one embodiment, inlets 240 are mounted on the discharge chute 50 . The discharge chute 50 is a relatively short, straight, and wide duct, through which the airstream 17 discharged by impeller housing 40 passes quickly. Time for dropout of the leaf particles in the discharge chute 50 is limited and fouling of the discharge chute 50 internal surface is minimized. In a further embodiment, it will also be possible to provide the inlets 240 for fluid spray within the collector 55 . The hose 230 conducts the fluid from the tank of fluid 210 to the fluid pump 220 and from fluid pump 220 to inlets 240 . Fluid spray is initiated during vacuuming operation and secured when the vacuuming is stopped. The invention may use water as an economical, effective, and environmentally benign fluid for the fluid injection apparatus 200 .
[0032] The fluid spray may also be used on leaf collection machines that are exhausting leaves into traditional leaf collection boxes with screened roofs. The fluid injection apparatus 200 , used with the traditional collector, will also improve the working environment around the collector.
[0033] Various modifications and variations of the described apparatus and methods of the invention 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, outlined above, it should be understood that the invention should not be unduly limited to such specific embodiments. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims. | A leaf collection apparatus and method whereby leaves are vacuumed into a collector in a manner to reduce dust spread to the area around the equipment and on the equipment operators. Leaves are discharged by a vacuum device into a collector and retained by screened internal walls. Fine leaf particulate passes through the screens and is directed through the floor to the ground under the collector where the particulate accumulates to facilitate collection. Reusable dust bags may be placed under the floor of the discharge path to collect the particulate matter as it is exhausted through openings in the floor. A fluid spray may be injected into the discharge of the vacuum collection device to wet the leaf particulate and facilitate settling within the collection box. | 4 |
FIELD OF THE INVENTION
[0001] This invention relates generally to data processing and providing information and services to a user based upon the user' position as determined by a navigational system.
BACKGROUND OF THE INVENTION
[0002] In today' world of ever-increasing travel and mobile computing, and with a multitude of news, products and services catering to the mobile public, it is still a difficult proposition to locate providers of various goods and services while traveling. A need arises for a way to rapidly discover service and product providers while traveling. A further need arises for a way for businesses, including but not limited to restaurants, gas stations, and retail stores, to register their offerings and locations with a central service provider for exposure and advertising to mobile travelers within a preset geographic distance. Once registered, any mobile person would then be able to be guided to the chosen place of business, once in a general proximity of the selected place of business. The need includes providing the mobile traveler with both navigational instructions to the registered business and providing information on specific services/products available from the registered business. A further need exists for a way for pro-active advertising and discounted specials (i.e. “electronic coupons”) of the registered businesses to be provided directly to the mobile traveler.
SUMMARY OF THE INVENTION
[0003] The invention that meets the needs identified above is a Waypoint Services Navigational System (WSNS) comprising a mobile unit connected to a server and to a database by the Internet. The WSNS uses omnipresent digital cellular links or any other form of radio frequency communications for transmission of information by a registered services provider to a traveler with a WSNS mobile unit. Using WSNS, the registered service provider announces its presence along with specific services/products to a traveler with a WSNS mobile unit within a predefined geographic radius. This information may be viewed via a conventional mobile computer, a personal digital assistant screen, or through a Global Positioning System (GPS) mapping longitude/latitude device. The WSNS mobile unit may be portable or mounted in a vehicle in a convenient location. Specific directions to a selected services provider are provided based upon the proximity positioning information at that moment in-time when the information is requested. Advertising specials, competitive services/products, entertainment, or emergency services may all be broadcast, and the user may choose from menus for the nature of services desired. Information may be provided regarding “upcoming” service providers through a combination of user geographical location, user directional data, and overlay maps showing registered businesses. Products or services may be ordered through a WSNS online order system for placing credit-or account backed purchases using the WSNS combination of locational information and business registration. WSNS service may also be provided through conventional internet-only communications, downloadable into a GPS-attached mobile computer to alleviate the need for a cellular link to the car.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] [0004]FIG. 1 is an illustration of a distributed data network;
[0005] [0005]FIG. 2 is an illustration of a data processing system;
[0006] [0006]FIG. 3 is an illustration of a data processing system;
[0007] [0007]FIG. 4 is an illustration of the WSNS system;
[0008] [0008]FIG. 5 is a flow chart of the target business registration process;
[0009] [0009]FIG. 6 is a flow chart of the WSNS server registration process;
[0010] [0010]FIG. 7A is a flow chart of the WSNS user set up process;
[0011] [0011]FIG. 7B is a continuation flow chart of the WSNS user set up process;
[0012] [0012]FIG. 7C is a continuation flow chart of the WSNS user set up process;
[0013] [0013]FIG. 7D depicts the relationship of the available and immediate radii used by WSNS;
[0014] [0014]FIG. 7E depicts the available and immediate forward distance parameters used by WSNS;
[0015] [0015]FIG. 8 is a flow chart of the WSNS user request process;
[0016] [0016]FIG. 9 is a flow chart of the WSNS server request answering process;
[0017] [0017]FIG. 10 is a flow chart of the WSNS server ordering process; and
[0018] [0018]FIG. 11 a flow chart of the WSNS CD-Rom process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] As used herein, Radius immediate shall mean and be numerically equal to the number of miles/kilometers around a vehicle for which to display businesses as being optimal for stopping.
[0020] As used herein, ForwardDistance immediate shall mean and be numerically equal to the forward distance before a vehicle, given the current direction of driving, for which to display optimal businesses.
[0021] As used herein, LateralDistance shall mean the perpendicular distance away from the highway at the point where ForwardDistance is calculated, and may be factored in either absolute terms, or via a suitable trigonometrical function. For example, if a business requires five miles forward and one mile lateral movement, it may or may not be considered “forward.” Similarly, if reaching a business requires one mile forward and five mile lateral movement, it may or may not be considered “forward.” Again, this will depend on lateral or angular permissiveness, contingent on implementation principles.
[0022] As used herein, Radius available means and is numerically equal to the number of miles/kilometers greater than the Radius immediate that is around the vehicle in which WSNS will display businesses as being available for stopping.
[0023] As used herein, ForwardDistance available means and is numerically equal to the Forward Distance, greater than ForwardDistance immediate that is before the vehicle, given current direction of driving, for which to display available businesses. Trigonometric or absolute lateral permissiveness factors will apply depending upon implementation design parameters.
[0024] As used herein, the term “target business” shall mean a business that has registered with the Waypoint Services Navigational System service provider so that information can be provided to travelers, orders placed and orders received through the Waypoint Services Navigational System service provider.
[0025] As used herein, the term Geographic Information Systems (GIS) table, means a list compiled by the WSNS server of all available businesses within a specified distance of the mobile user, based upon prior business registration information. The resultant list of compiled businesses will be displayed, by category, within the car, possibly but not necessarily on a dashboard display. Speech synthesis or recording of business names and distances from current location may also be used for compilation and presentation and may be either Radius immediate ForwardDistance immediate Radius available or ForwardDistance available Furthermore, the WSNS may present an ordered list, in ascending or descending order, of business by distance. Likewise, it is possible for the WSNS to present the list in gradients, either as two degrees of desirability as outlined here (i.e., “immediate” and “available”) or in even greater degrees of desirability.
[0026] [0026]FIG. 1 depicts a pictorial representation of a distributed data processing system in which the present invention may be implemented and is intended as an example, and not as an architectural limitation, for the processes of the present invention. Distributed data processing system 100 is a network of computers which contains a network 102 , which is the medium used to provide communication links between the various devices and computers connected together within distributed data processing system 100 . Network 102 may include permanent connections, such as wire or fiber optic cables, or temporary connections made through telephone connections. In the depicted example, a server 104 is connected to network 102 along with storage unit 106 . In addition, clients 108 , 110 , and 112 also are connected to a network 102 . Clients 108 , 110 , and 112 may be, for example, personal computers or network computers.
[0027] For purposes of this application, a network computer is any computer, coupled to a network, which receives a program or other application from another computer coupled to the network. In the depicted example, server 104 provides Web based applications to clients 108 , 110 , and 112 . Clients 108 , 110 , and 112 are clients to server 104 . Distributed data processing system 100 may include additional servers, clients, and other devices not shown. In the depicted example, distributed data processing system 100 is the Internet with network 102 representing a worldwide collection of networks and gateways that use the TCP/IP suite of protocols to communicate with one another. Distributed data processing system 100 may also be implemented as a number of different types of networks, such as, an intranet, a local area network (LAN), or a wide area network (WAN).
[0028] Referring to FIG. 2, a block diagram depicts a data processing system, which may be implemented as a server, such as server 104 in FIG. 1 in accordance with the present invention. Data processing system 200 may be a symmetric multiprocessor (SMP) system including a plurality of processors such as first processor 202 and second processor 204 connected to system bus 206 . Alternatively, a single processor system may be employed. Also connected to system bus 206 is memory controller/cache 208 , which provides an interface to local memory 209 . I/O bus bridge 210 is connected to system bus 206 and provides an interface to I/O bus 212 . Memory controller/cache 208 and I/O bus bridge 210 may be integrated as depicted. Peripheral component interconnect (PCI) bus bridge 214 connected to I/O bus 212 provides an interface to first PCI local bus 216 . Modem 218 may be connected to first PCI bus local 216 . Typical PCI bus implementations will support four PCI expansion slots or add-in connectors. Communications links to network computers 108 , 110 and 112 in FIG. 1 may be provided through modem 218 and network adapter 220 connected to first PCI local bus 216 through add-in boards. Additional PCI bus bridges such as second PCI bus bridge 222 and third PCI bus bridge 224 provide interfaces for additional PCI local buses such as second PCI local bus 226 and third PCI local bus 228 , from which additional modems or network adapters may be supported. In this manner, server 200 allows connections to multiple network computers. A memory-mapped graphics adapter 230 and hard disk 232 may also be connected to I/O bus 212 as depicted, either directly or indirectly. Those of ordinary skill in the art will appreciate that the hardware depicted in FIG. 2 may vary. For example, other peripheral devices, such as an optical disk drive and the like also may be used in addition or in place of the hardware depicted. The depicted example is not meant to imply architectural limitations with respect to the present invention. The data processing system depicted in FIG. 2 may be, for example, an IBM RISC/System 6000 system, a product of International Business Machines Corporation in Armonk, N.Y., running the Advanced Interactive Executive (AIX) operating system.
[0029] With reference now to FIG. 3, a block diagram illustrates a data processing system in which the invention may be implemented. Data processing system 300 is an example of either a stand-alone computer, if not connected to distributed data processing system 100 , or a client computer, if connected to distributed data processing system 100 . Data processing system 300 employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Micro Channel and ISA may be used. Processor 302 and main memory 304 are connected to PCI local bus 306 through PCI bridge 303 . PCI bridge 303 also may include an integrated memory controller and cache memory for Processor 302 . Additional connections to PCI local bus 306 may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter 310 , SCSI host bus adapter 312 , and expansion bus interface 314 are connected to PCI local bus 306 by direct component connection. In contrast, audio adapter 316 , graphics adapter 318 , and audio/video adapter (A/V) 319 are connected to PCI local bus 306 by add-in boards inserted into expansion slots. Expansion bus interface 314 provides a connection for a keyboard and mouse adapter 320 , modem 322 , and additional memory 324 . SCSI host bus adapter 312 provides a connection for hard disk drive 326 , tape drive 328 , and CD-ROM 330 in the depicted example. Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. An operating system runs on processor 302 and is used to coordinate and provide control of various components within data processing system 300 in FIG. 3. The operating system may be a commercially available operating system such as OS/2, which is available from International Business Machines Corporation. “OS/2” is a trademark of International Business Machines Corporation. An object oriented programming system, such as Java, may run in conjunction with the operating system and provides calls to the operating system from Java programs or applications executing on data processing system 300 . “Java” is a trademark of Sun Microsystems, Incorporated. Instructions for the operating system, the object-oriented operating system, and applications or programs may be located on storage devices, such as hard disk drive 326 , and they may be loaded into main memory 304 for execution by processor 302 .
[0030] Those of ordinary skill in the art will appreciate that the hardware in FIG. 3 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash ROM (or equivalent nonvolatile memory) or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIG. 3. Also, the processes of the present invention may be applied to a multiprocessor data processing system. For example, data processing system 300 , if configured as a network computer, may not include SCSI host bus adapter 312 , hard disk drive 326 , tape drive 328 , and CD-ROM 330 , as noted by the box with the dotted line in FIG. 3 denoting optional inclusion. In that case, the computer, to be properly called a client computer, must include some type of network communication interface, such as LAN adapter 310 , modem 322 , or the like. As another example, data processing system 300 may be a stand-alone system configured to be bootable without relying on some type of network communication interface, whether or not data processing system 300 comprises some type of network communication interface. As a further example, data processing system 300 may be a Personal Digital Assistant (PDA) device which is configured with ROM and/or flash ROM in order to provide non-volatile memory for storing operating system files and/or user-generated data. The depicted example in FIG. 3 and above-described examples are not meant to imply architectural limitations with respect to the present invention. It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in a form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media, such a floppy disc, a hard disk drive, a RAM, and CD-ROMs, and transmission-type media, such as digital and analog communications links.
[0031] [0031]FIG. 4 is an illustration of WSNS system 400 . WSNS mobile unit 410 comprises microprocessor 412 connected to a processor memory 414 . WSNS mobile unit 410 may be configured for vehicle installation or stand alone use by connecting 410 to one or more of the following: memory 416 , display 418 , CD-Rom 422 , keyboard 420 , transmitter/receiver 424 , global positioning system 428 , personal digital assistant (PDA) 452 and printer 454 . In the preferred embodiment, display 418 is a “heads up display” that will project the data from WSNS system 400 onto the inside of the windshield of the automobile (not shown) in which WSNS mobile unit 410 is installed. The “heads up display” allows the driver to access data from WSNS system 400 without turning his vision away from the direction of travel. Alternatively, display unit 418 may be any type of suitable display known to persons skilled in the art. Also in the preferred embodiment, mobile unit 410 is connected by transmitter/receiver 424 to cellular/RF communications network 430 and cellular/RF network 430 is connected to Internet 440 . Client computer 442 , target business computer 444 , database 446 and server 448 are illustrative of the hardware that mobile unit 410 communicates with via the Internet.
[0032] [0032]FIG. 5 depicts a flow chart of target business registration process 500 . A target business may sign up with the WSNS service provider through a variety of means including but not limited to telephone or the Internet. Depending on the business model followed, a cost may or may not be incurred by the business registering with the service. Additionally, advantages exist for chambers of commerce and other such business promotion entities, to promote local ventures by mass-registering the proprietors within their jurisdiction. Target business registration process 500 begins ( 510 ) and the target business contacts WSNS service provider ( 520 ). The target business enters the type of business in which the target business is engaged ( 530 ). Examples of the type of business may include without limitation one or more of the following: lodging, fuel, or food. The target business enters its location ( 540 ). If the target business has any incentives that it may want to offer, these can be entered ( 550 ). Incentives include without limitation discounts or electronic coupons. The user at the target business reviews the entered data to check for accuracy and completeness ( 560 ) and sends the data to the WSNS service provider ( 570 ). If an error message is received, target business registration process 500 goes to step 530 to check and re-enter data. If an error message is not received, target business registration process 500 saves the information ( 580 ) and stops ( 590 ). Persons skilled in the art will recognize the interchangeability of steps for the entry of data in FIGS. 5.
[0033] [0033]FIG. 6 is a flow chart of the WSNS server registration process. Server registration process 600 begins ( 610 ) and target business information submitted by target business registration process 500 is received ( 620 ). A determination is made as to whether the information received is complete ( 630 ). If the information is not complete, an error message describing the incomplete information is sent to the target business ( 640 ) and server registration process 600 goes to step 620 . If the information is complete, server registration process 600 enters the target business information in a Geographic Information Systems (GIS) table ( 650 ). A determination is made as to whether there is another target business to process ( 660 ). If there is another target business, server process 600 goes to step 620 and if not ends ( 670 ).
[0034] [0034]FIG. 7A is a flow chart of the WSNS user interface set up process. Set up process 700 begins ( 702 ) and the user turns the power on for mobile unit 410 (see FIG. 4). A user driving on a given road, with the WSNS available, will switch on the system. In the preferred embodiment, mobile unit 410 will be installed in a vehicle but may also be handheld carried by a pedestrian. Upon power-on ( 704 ), or other initiation of active engagement, the mobile unit 410 will use existing technology to register location and directional information with a WSNS central server. The existing technology includes without limitation the Global Positioning System (GPS). The granularity of position resolution may be sub-mile which may be achieved with current methodologies. A desirable resolution will be within several meters, consistent with current technologies. Mobile unit 410 displays a graphical user interface/menu to guide the user through the set up process ( 706 ). The user identifies the trip for which data will be entered ( 708 ). The user selects either Radius immediate or Radius available ( 710 ). Next, the user selects either ForwardDistance immediate or ForwardDistance available ( 712 ). The user sets desirability preferences, if different from those selected in step 710 and 712 ( 714 ). Next the user sets the position determination preference ( 716 ). The user sets order preferences ( 718 ). A determination is made as to whether the user wants to select options ( 720 ). If the user does not want to select options, then a determination is made as to whether parameters and preferences for another trip are to be entered ( 722 ). If another trip is not to be entered, power is turned off ( 724 ) and set up process 700 ends ( 750 ). If another trip is to be entered, set up process 700 goes to step 708 .
[0035] Referring to FIG. 7B, if at step 720 , a determination is made that the user wants to select options, then a determination is made as to whether the user wants to enter payment data ( 726 ). If the user wants to enter payment data, the user selects payment mode ( 728 ), enters the payment data ( 730 ) and set up process 700 goes to step 732 . If the user does not want to enter payment data, a determination is made as to whether the user wants to receive advertising ( 732 ). Advertising may be desirable for the following reasons. If the user chooses to leave his or her mobile unit powered on for any length of time (a likely possibility, resulting in a continuous stream of updates to the mobile unit), it may be advantageous to allow and to even encourage onboard advertising. In this implementation, a user may have upcoming businesses displayed in any of the previously mentioned formats, while a separate portion of the screen (or intermittent voice-delivered messages over the WSNS link) will offer words of advertisement and/or special promotions to the user. It is further possible that the user will have “WSNS-only” promotions available, through which he or she can receive reduced rates and prices at local businesses. If the user wants to receive advertising, a determination is made as to whether the user wants to receive visual advertising ( 734 ). If the user wants to receive visual advertising, the user sets visual parameters ( 736 ). If the user does not want to receive visual advertising, a determination is made as to whether the user wants to receive audio advertising ( 738 ). If the user wants to receive audio advertising, the user sets audio parameters ( 740 ). A determination is made as to whether the user wants to receive pre-travel information ( 742 ). If the user wants to receive pre-travel information, the user sends the itinerary for which the pre-travel information is desired ( 744 ) and selects a method of delivery for the pre-travel information ( 746 ).
[0036] The user' credit card number (or analogous account information) may be stored on the WSNS mobile unit (including memory sticks) and broadcast to the service provider when goods or services are desired, or it could be stored in a local trusted server, for conveyance to the business when stipulated by the user. For example, the mobile user may select an item via either keyboard, touch-sensitive screen, or via speech queues, to the WSNS options displayed on his or her mobile unit. This information is conveyed back to the WSNS provider via RF links (possibly, but not necessarily, through cellular telephone/personal communications systems frequencies). The WSNS provider provides the information to the target business through one of several means. These means may include human intervention via telephone, fax machine, email or other electronic communications. The credit card number or account information will be provided to the target business, so that food will be prepared, rooms will be held, et cetera, based upon the financial backing for the order being placed.
[0037] Referring to FIG. 7C, set up process 700 continues and the user determines whether or not to utilize personal profile information. The personal profile information may be used by the WSNS server to identify target businesses with products and services that meet the particular needs of the user' profile. For example, such general items as age, educational background, and interest items may be entered as well as specific items such as brand preferences for particular food, lodging, gasoline or automotive products. If the user desires to use the personal profile option, then the user enters profile data to be used by the WSNS server and set up process 700 goes to step 752 . If the user does not want to use the personal profile option, then the user makes a determination as to whether the expense tracking option is desired. The expense tracking option allows the user to receive a summary of trip expenses where the expenses are incurred from the WSNS target businesses. If the expense tracking is desired, then the user chooses whether or not the user will enter expense data into the system during the trip ( 754 ). If the user does not want to enter data, the user will select a target business report option ( 756 ) and transaction information will be gathered by the WSNS server from the target business when a transaction is made. If the user decides to enter the data, the user entry is selected ( 758 ). For user entry to be accomplished, the user will have to have hardware to scan in receipts, or alternatively a keyboard, touchscreen, or voice recognition capability to transmit the transaction data from the WSNS mobile unit 410 for summarization and reporting by the WSNS server at the conclusion of the trip. Set up process 700 then goes to step 722 . Persons skilled in the art will recognize the interchangeability of steps for the entry of data, preferences or for the selection of options in FIGS. 7A through 7C.
[0038] [0038]FIG. 7D depicts the relationship of the available and immediate radii used by WSNS. Radius immediate establishes a circle that is smaller than the circle established by Radius available .
[0039] [0039]FIG. 7E depicts the available and immediate forward distance parameters used by WSNS. ForwardDistance immediate is smaller than ForwardDistance available ForwardDistance immediate has LateralDistance 774 and ForwardDistanceavailable has LateralDistance 784 .
[0040] [0040]FIG. 8 is a flow chart of the WSNS user request process. Request process 800 begins ( 802 ) and power is turned on ( 810 ). The user registers with the WSNS server ( 820 ). If necessary, the WSNS server will prompt the user for verification of the road currently being traveled. Such verification may be necessary in urban areas, where road density is high. If GPS is being used, then such verification would probably be unnecessary. Therefore, a determination is made as to whether verification is necessary ( 830 ). If verification is necessary, the user will enter the road designation ( 840 ) and request process 800 goes to step 830 . If verification is not necessary, mobile unit 410 will receive the data ( 850 ) and display the data ( 860 ). A determination is made as to whether the user wants to continue to receive data ( 870 ). If the user desires to continue to receive data, request process 800 goes to step 820 . If the user does not desire to continue to receive data, mobile unit 410 powers off ( 880 ) and request process 800 ends.
[0041] [0041]FIG. 9 is a flow chart of the WSNS server request answering process 900 . Answering process begins ( 902 ) and a request is received from a user ( 904 ). A determination is made as to whether the request is for an immediate real time response ( 906 ). If the request is not for an immediate real time response, then answer process 900 receives the route information from the user ( 908 ), identifies all matches on the route ( 910 ) and saves the match file ( 912 ). A determination is made as to whether to send the match file electronically ( 914 ). If the match file is to be sent electronically, then the match file is sent ( 918 ) and answer process 900 goes to step 932 . If the match file is not to be sent electronically, then answer process 900 will place the match file on magnetic media for delivery by mail ( 916 ). If at step 906 a determination is made that the user is requesting immediate information in real time, then the user information is received ( 920 ). A determination is made as to whether the user needs to verify the position location ( 922 ). If verification is needed, a message is sent ( 924 ) and answer process 900 goes to step 920 . If verification is not needed, then user preferences are loaded ( 926 ). The user position is compared to the GIS table ( 928 ). Matches from the GIS table are sent to the user ( 930 ). A determination is made as to whether another request is made ( 932 ). If another request is made, answer process 900 goes to step 904 . If not, answer process 900 ends ( 940 ).
[0042] [0042]FIG. 10 is a flow chart of the WSNS server ordering process 1000 . User set up process 700 considered that specific business offerings and prices may be displayed or otherwise conveyed to the customer. Order process 1000 begins ( 1005 ). The WSNS server receives an order to be placed with a target business from a user ( 1010 ) and accesses target business information ( 1020 ). For example, if the target business is a restaurant, the order may be for an amount of food from a menu with prices. If the target business is a hotel, the order may be a room at the rate provided. A determination is made as to whether the target business is on the Internet ( 1030 ). If the target business is not on the Internet, the WSNS server sends the order by phone or fax transmission ( 1040 ). If the target business is on the Internet, the order is sent by the Internet ( 1050 ). Order process 1000 receives confirmation from the target business that the order has been received ( 1060 ) and sends confirmation to the user ( 1070 ). A determination is made as to whether another order is received ( 1080 ). If another order is received, order process 1000 goes to step 1010 . If another order is not received, order process ends ( 1090 ).
[0043] [0043]FIG. 11 a flow chart of the WSNS CD-Rom process. CD-Rom process provides pre-travel information. Prior to travel, the user provides the WSNS service provider his or her intended route. The WSNS will provide, through well-known download principles, business contact information which might be found along the route. This download will be placed upon some form of media, ranging from real memory, to flash memory, to traditional physical media types such as CD-RW or diskette, as is readable by the mobile unit. This media will be placed within the mobile unit prior to the trip. Within this implementation, the mobile unit will use positional data, such as that provided by GPS, to track movement relative to a GIS overlay map. The mobile unit will similarly display business information as the traveler moves along the route, achieving an effect similar to that obtained using the full-RF implementation. CD-Rom process 1100 begins ( 1110 ) and power is tuned on ( 1120 ). The user loads the CD-Rom in mobile unit 410 ( 1130 ). The user enters parameters for the present position into mobile unit 410 and data is displayed from the CD-Rom. A determination is made as to whether the user wants to continue using the CD-Rom ( 1160 ). If the user wants to continue using the CD-Rom, a determination is made as to whether the user wants to change the parameters. If the user wants to change the parameters, CD-Rom process 1100 goes to step 1410 . If the user does not want to change parameters, CD-Rom process 1100 goes to step 1150 . If the user does not want to continue at step 1160 , CD-Rom process ends ( 1180 ).
[0044] With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. | A Waypoint Services Navigational System (WSNS) is disclosed comprising a mobile unit connected to a server and to a database by the Internet. The WSNS uses omnipresent digital cellular links or any other form of radio frequency communications for transmission of information by a registered services provider to a traveler with a WSNS mobile unit. Using WSNS, the registered service provider announces its presence along with specific services/products to a traveler with a WSNS mobile unit within a predefined geographic radius. This information may be viewed via a conventional mobile computer, a personal digital assistant screen, or through a Global Positioning System (GPS) mapping longitude/latitude device. The WSNS mobile unit may be portable or mounted in a vehicle in a convenient location. Specific directions to a selected services provider are provided based upon the proximity positioning information at that moment in-time when the information is requested. Advertising specials, competitive services/products, entertainment, or emergency services may all be broadcast, and the user may choose from menus for the nature of services desired. Information may be provided regarding “upcoming” service providers through a combination of user geographical location, user directional data, and overlay maps showing registered businesses. Products or services may be ordered through a WSNS online order system for placing credit-or account backed purchases using the WSNS combination of locational information and business registration. WSNS service may also be provided through conventional internet-only communications, downloadable into a GPS-attached mobile computer to alleviate the need for a cellular link to the car. | 7 |
RELATED APPLICATIONS
This application is a Continuation of U.S. application Ser. No.10/131,302, filed on Apr. 24, 2002, now U.S. Application Publication No. 2003/0053671 A1, published on Mar. 20, 2003, which claims priority to European Patent Application No. 01000142.8, filed on May 10, 2001, and also claims benefit of U.S. Provisional application No. 60,294,708, filed on Mar. 31, 2005, all of which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to a method for correcting inhomogeneities in a digital radiation image which are inherent to the use of a radiation source, a radiation detector or a radiation image read-out apparatus or the like.
BACKGROUND OF THE INVENTION
Digital radiography offers the possibility for computer aided diagnosis and quantitative analysis using image processing techniques such as segmentation, classification and contrast enhancement. However, computer-based image interpretation may be hindered by the presence of the non-uniformities in radiation exposure that are inherent to the image formation.
In the field of X-ray exposure these non-uniformities can be largely attributed to the Heel effect, nevertheless other sources of inhomogeneities exist such as recording member non-uniformities or read-out inhomogeneities.
Although the intensity inhomogeneities induced by all these factors are smoothly varying as a function of location and are easily corrected by the human visual perception system, they complicate the use of automatic processing techniques because the relative brightness of an object within the image becomes position dependent. The overall intensity range is unnecessarily enlarged by the presence of these slowly varying shading components and hence the dynamic range available to represent diagnostic signal details is reduced.
A typical hand radiograph is shown in FIG. 1 . The background at the left side of the image is clearly brighter than at the right side. This phenomenon can be attributed to the so-called Heel effect. Because beam collimator blades substantially attenuate the X-ray beam so as to shield irrelevant body parts, the phenomenon is only visible in the direct exposure and diagnostic areas and not in the collimation area. The Heel effect can be understood from the construction of the X-ray tube as schematically depicted in FIG. 2 . Electrons originating from the cathode are attracted by the positively charged anode. For better heat dissipation, the anode rotates and is inclined by a small anode angle θ, which enlarges the area A actual that is bombarded by electrons while keeping the size of the focal A eff , from, which rays are projected downward to the object, fairly small. As shown in the diagram of FIG. 3 , this design makes the length of the path travelled by the X-rays through the anode larger on the anode side of the field T a than on the cathode side T c . Hence the incident X-ray intensity is smaller at the anode side than at the cathode side of the recording device, which explains the inhomogeneity of the background in FIG. 1 .
The Heel effect is one possible cause of Intensity inhomogeneities that can be introduced in radiographs. As has already been mentioned higher, other causes of non-uniformities might be envisioned such as non-uniform sensitivity of the recording member, e.g. a photographic film, a photostimulable phosphor screen, a needle phosphor screen a direct radiography detector or the like. Still another cause might be non-uniformities of the read-out system which is used for reading an image that has been stored in a recording member of the kind described above.
Because the image acquisition parameters that affect intensity inhomogeneity vary from image to image (e.g. variable positioning of the recording device relative to the X-ray source) and can not be recovered from the acquired image at read-out, correction methods based on calibration images or flat field exposure such as the one described in EP-A-823 691 are not feasible.
The method disclosed in EP-A-823 691 comprises the steps of (1) exposing an object to radiation emitted by a source of radiation, (2) recording a radiation image of said object, on a radiation-sensitive recording member, (3) reading the image that has been stored in said recording member and converting the read image into a digital image representation, (4) generating a set of correction data and (5) correcting said digital image representation by means of said set of correction data. The set of correction data is deduced from data corresponding with a uniform, flat field exposure of the recording member. The set of correction values represent the deviation of the value that is effectively obtained in a pixel of the recording member and a value that would be expected in the case of flat field exposure. These correction values associated with each recording member are normally determined once and kept fixed during further acquisition cycles.
This type of methods is not applicable for solving problems such as the introduction of inhomogeneities due to the Heel effect.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a method to correct a digital image for artifacts such as artifacts which are inherent no the use of an X-ray tube, artifacts originating from defects in a radiation detector or the like.
Further objects will become apparent from the description hereafter.
SUMMARY OF THE INVENTION
The above mentioned objects are realised by a method having the specific features set out in claim 1 .
Unlike the state of the art methods, in the present invention a set or correction data is deduced from the actual image data obtained by exposing an object to radiation and not from an additional image such as an image representing a flat field exposure.
A radiation image most generally comprises a Collimation area which is an area that has been shielded from exposure to radiation by shielding elements, a direct exposure area (also called background area) being the area on the recording member that has been exposed to direct, unmodulated irradiation and a diagnostic area which is the area where the radiation image is found of the body that was exposed to radiation.
Because of substantial attenuation of the X-ray beam when passing through the collimator blades, the dynamic range of the irradiation has been reduced to an extent so as to make these collimation areas unsuitable for estimation of the correction values.
Because the causes that introduce inhomogeneities are not present in the collimation area the collimation area can be neglected in the method of the present invention. A segmentation algorithm can be used to find the boundaries of the collimation area to exclude these areas from further consideration. An example of such an algorithm has been described in European patent applications EP-A-610 605 and EP-A-742 536 (for the case of a partitioned image), these documents are incorporated by reference.
FIRST EMBODIMENT
In one embodiment (1) a mathematical model representing the phenomenon that induces the inhomogeneities is generated. Next (2) the digital image representation is subjected to image segmentation in order to extract data representing an estimation of the direct exposure area. Then, (3) parameters of this model are deduced from image data representing the direct exposure area in the image. Next (4) bias field is generated on the basis of the deduced parameters. Next, (5) a correction by means of said bias field is applied to the image data. Corrected image data are then subjected to a stopping criterion. Unless this stopping criterion is met, steps (2) to (6) are repeated.
Because the inhomogeneities are only directly measurable in the directs exposure areas or the image, this area is preferably first extracted and the parameters of the model are estimated from the data regarding this region only. A seed fill algorithm can be used to determine the background area. The seed fill algorithm can be started front the boundary of the collimation area.
Inhomogeneity correction by applying a bias field is performed on the entire image. In the context of the present invention the term ‘a bias field’ is used to denote a low frequency pattern that is superimposed on the average image data values in a multiplicative or additive manner.
Next a new background region is extracted from the corrected image data and the model parameters are re-estimated. This sequence is repeated. The method iterates between background segmentation and correction until convergence, i.e. until no significant changes in background or parameter estimation occur.
SECOND EMBODIMENT
In a second embodiment according to the present invention a statistical model of the image is first generated on the basis or intensity and spatial statistics of image regions in the image.
The digital image representation is then subjected to image segmentation in order to extract data, constituting, an estimation of these image regions. The image regions referred to are e.g. direct exposure area, bone image, soft tissue image etc.
Parameters of the statistical mode are estimated by means of data pertaining to these image regions. Next, a bias field comprising correction data is generated and the entire image, is corrected by means of the bias field. The result of the previous step is evaluated relative to a stopping criterion. The method steps of segmenting, bias field correction and evaluation are repeated until the stopping criterion is met. The stopping criterion is e.g. reached when no significant changes occur in the estimation of the image regions and/or no significant changes occur in the parameters defining the statistical model.
In one embodiment the image regions are confined to direct exposure areas. In another embodiment (see fourth embodiment) the method steps are applied separately to each of a number of image region classes jointly constituting the intensity histogram of the radiation image.
In one embodiment the statistical model is a Gaussian distribution and the parameters of the statistical model are the statistical parameters defining the statistical model such as average value μ of the Gaussian distribution and the standard deviation σ.
The stopping criterion is e.g. reached when no significant changes occur in the estimation of image regions and/or no significant changes occur in the parameters defining the statistical model.
THIRD EMBODIMENT
A third embodiment is based on the observation that the entropy of an image increases if inhomogeneities are induced in the image.
In a third embodiment of the method of the present invention an information theoretic model of the image comprising a least direct exposure areas and diagnostic areas is generated. The model is based on Shannon-Wiener entropy increasing when additional intensity value entries are added to the image intensity distribution. The digital image representation is subjected to image segmentation in order to extract data representing an estimation of the direct exposure areas and the entropy in said models extracted based on of data pertaining to these areas. Next, a bias field is generated and the entire image is corrected by means of the bias field. The result of the previous step is evaluated relative to a stopping criterion and the method is repeated until said stopping criterion is met. A stopping criterion is e.g. met when the entropy is minimal and no significant changes occur in it.
FOURTH EMBODIMENT
The fourth embodiment is a more general case of the second embodiment in this fourth embodiment the method steps of the second embodiment are applied separately to each of a number of image region classes jointly constituting the intensity histogram of the radiation image.
In all of the aforementioned embodiments, the number of iterations may be restricted to one when less precision is needed and hence the stopping criterion need not be evaluated.
Further advantages and embodiments of the present invention will be one apparent from the following description [and drawings].
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a typical radiographic image of a hand in which the Heel effect is clearly visible on the direct exposure area,
FIGS. 2 and 3 are schematic side views of an X-ray tube,
FIG. 4 is a coordinate system, wherein an X-ray originates at position (0,0) and travels along R to the recording medium at position (p, D is ).
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
A mathematical model for the Heel effect can be derived from the simplified one-dimensional model of the anode and bean geometry depicted in FIG. 4 . In the coordinate system (p,z), with p along the anode-cathode axis and z along the vertical direction, the X-rays can be taught off to originate within the anode at point ω(0,0), at a distance D ave from the anode surface S. Consider the ray R at an angle φ from the vertical within the plane (ω,S) that hits the recording device at point (p,D is ) with D is the distance between the X-ray source and the recording device and
tan ϕ = p D is .
The distance r traveled by R through the anode is given by
r =|ξ−ω|=√{square root over ( p R 2 +z R 2 )} (1)
with ξ(p R ,z R ) the intersection of R with S which can be found by solving the system of equations:
S:p R =D ave −tan δ. z R (2)
R:p R =tan φ, z R
Hence,
r
(
p
)
=
D
ave
cos
θ
sin
(
ϕ
+
θ
)
=
D
ave
1
+
(
p
D
is
)
2
tan
θ
+
p
D
is
(
3
)
The radiation received on the recording device is
M(p)=I o ,e −μ,r(p) (4)
with μ the attenuation coefficient of the anode material and I o the radiation originating at ω.
Model (4) predicts that the Heel effect behaves exponentially along the anode-cathode axis and assumes that it is constant perpendicular to this axis. This is justified by flat filed exposure experiments which show that the difference in intensity perpendicular to the anode-cathode axis is relatively small compared to the intensity differences along the anode-cathode axis.
Image Segmentation:
A typical hand radiograph, as shown in FIG. 1 , consists of three regions: collimation area (numeral 1 ), direct exposure area (numeral 2 ) and diagnostic regions (numeral 3 ). Because the Heel effect is largely reduced in the collimation area and directly measurable in the direct exposure area only, the image needs to be segmented to fit model (4) to the image intensity data. This is obtained by first extracting the collimation area and then searching the direct exposure area, the remaining areas being diagnostic regions.
The boundaries of the collimation area have been round using the Hough transform assuming that these are rectilinear edges as is the case for the majority of X-ray source-mounted collimation devices. To make this approach more robust, the contributions of each image point to the Hough space accumulator are weighted by said point's gradient magnitude and, for each point, only lines the direction of which is within 10 degrees from the normal the local gradient direction are considered. The 4 most salient points in Hough space that represent a quadragon with inner angles between 80 and 100 degrees are selected as candidate boundaries of the collimation area. Because not all 4 collimation shutter blades leave an imprint in the image and hence make the associated boundaries disappear in the image, candidate boundaries along which the image intensity differs from the intensity expected for the collimation region are rejected.
To extract the background region B, a seed fill algorithm has been used that starts from the boundary of the collimation region as determined in the previous step. Appropriate seed points for B are found by considering a small band along each of the collimator edges and retaining all pixels whose intensity is smaller than the mean of the band. This approach avoids choosing pixels that belong to the diagnostic region as candidate seed pixels. B is then grown by considering all neighboring pixels n i , i=1, . . . , 8 of each pixel p∈B and adding q i to B if the intensity difference between p and q i is smaller than some specified threshold.
Heel Effect Estimation:
To fit the model (4) to the image data N (x,y) the direction γ has to be found of the anode-cathode axis and the parameters α=[I O ,μ,6,D is ,D ave ,p ω ] such that the model best fits the image data within the direct exposure area extracted thus far. p ω is a parameter introduced to map point ω where the X-ray originates to the correct image coordinates (see FIG. 4 ). For the case whereby the Heel effect is modulated as a one-dimensional phenomenon, the distance p ω and the angle γ are the required parameters to map the coordinate system attached to the X-ray origin, ω to the image plane coordinate system, However, because the anode has the three-dimensional shape of a cone, the Heel effect is a three dimensional phenomenon, in that at the intensity also slightly is reduced in a direction perpendicular to the (p,z) plane. To model the two-dimensional Heel effect in the image plane, a third geometry parameter p ω1 is needed. Parameters (p ω ,p ω1 ,γ) jointly define a coordinate system translation and rotation from the X-ray origin ω to an image plane origin, which is the center of the image e.g. in practice the Heel effect inhomogeneity in, said perpendicular direction is only small with respect to the Heel effect along the anode-cathode axis.
Assuming that γ is known, the average image profile P γ (p) along this direction in the direct exposure region B is given by
P γ ( p )=[ N ( x,y )] (x,y)∈B|x.cos γ+y.sin γ=p
with x and y the image coordinates as defined in FIG. 3 and [.] the averaging operator. We can then find the optimal model parameters α* by fitting the expected profile M (p,α) to the measured profile.
α
*
(
γ
)
=
arg
min
α
P
γ
(
p
)
-
M
(
p
,
α
)
(
5
)
The fitted one-dimensional model M(p,α*(γ)) is then back projected perpendicular to the projection axis γ to obtain a reconstruction R(x,y,γ,α*(γ)) for the whole image:
R ( x,y,γ,α* (γ))= M ( x. cos γ+ y .sin γ,α*(γ))
The direction of the anode-cathode axis γ is then determined such that this reconstruction best fits the actual image data within the direct exposure region using
γ
*
=
arg
min
γ
N
(
x
,
y
)
-
R
(
x
,
y
,
γ
,
α
*
(
γ
)
)
(
x
,
y
)
∈
B
or
(
6
)
γ
*
=
arg
min
γ
N
(
x
,
y
)
R
(
x
,
y
,
γ
,
α
*
(
γ
)
)
-
1
(
x
,
y
)
∈
B
(
7
)
depending on whether we wish to use additive or multiplicative correction. The estimated Heel effect is R(x,y,γ*,α*(γ*)) and the corrected image is respectively
N
^
(
x
,
y
)
=
N
(
x
,
y
)
-
R
(
x
,
y
,
γ
*
,
α
*
(
γ
*
)
)
or
(
8
)
N
^
(
x
,
y
)
=
N
(
x
,
y
)
R
(
x
,
y
,
γ
*
,
α
*
(
γ
*
)
)
.
(
9
)
The optimal parameters α* and γ* are found by multidimensional downhill simplex search. It has been noticed that the anode-cathode axis in, our setup is almost always parallel to the image or collimation edges, This reduces the number of orientations which have to be evaluated in (6-7) and reduces computation time.
After inhomogeneity correction of the image using (8-9), the direct exposure area B is up-dated by thresholding, using a threshold derived from the histogram of the corrected image intensities {circumflex over (N)}. Keeping the previously determined anode-cathode orientation γ, new values for the optimal model parameters α* are determined using (5) taking the newly selected direct exposure region into account. A number of iterations, typically three or four, have been performed between background segmentation and Heel effect correction until convergence.
Second and Third Embodiment
Image Formation:
In ideal circumstances, the image formation process or diagnostic digital X-ray images is usually well described by a multiplicative model yielding an intensity-uniform image U(x,y):
U ( x,y )= I.O ( x,y )
where O(x,y) represents the object in the image. In diagnostic X-ray images, the most important contributing process of the object is the linear attenuation of the X-rays by the bone and soft tissue
O ( x,y )= e −∫ o ζμ(r)dr
μ is the linear attenuation coefficient along the path between the origination X-ray at position ω and the recording device ζ. However, nonuniform illumination I=I(x,y), uneven sensitivity of the recording device and inhomogeneous sensitivity of the phosphors for readout, introduce unwanted intensity modulations in the acquired image N(x,y) described by function ƒ
N ( x,y )=ƒ x,y,U ( U ( x,y )) (10)
In the second and third embodiment the Heel effect is again, examined as a very important source of nonuniform illumination. Reference is made to FIGS. 2-4 which aid in explaining this effect.
Electrons originating from the cathode are attracted by the positively charged anode. For better heat dissipation, the anode rotates and is inclined by a small anode angle δ, which enlarges their area A actual that is bombarded by electrons while keeping the size of the focal spot A eff , from which rays are projected downward to the object, fairly small. As shown in the FIG. 3 , the design makes the length of the path travelled by the X-rays through the anode larger on the anode side of the field (T a ) than on the cathode side (T c ). Hence the incident X-ray intensity is smaller at the anode side of the recording device. A simple theoretical model is given by
I
(
x
,
y
)
-
I
o
ⅇ
-
μ
D
ave
1
+
(
p
D
is
)
2
tan
θ
+
p
D
is
(
11
)
with I o the radiation originating at ω,μ the linear attenuation coefficient of the anode, D ave the average distance traveled through the anode by the electrons, D is the distance between the X-ray source and the recording device and p the distance from the recording device to X-ray source projected onto the anode-cathode axis.
Although the second and third embodiment are explained with reference to the Heel effect, other source of inhomogeneities may be envisaged such as the molding process of imaging plates and/or the characteristics of the read-out system. In some fabrication processes, the concentration of phosphors at the edge of the plate is lower than the concentration in the middle of the plate which may result in a non-uniform image. In read-out apparatuses comprising mirror deflection, the displacements of the mirror has to be very accurately implemented to achieve uniform activation of the phosphors for read-out. Due to all these factors it is almost impossible to model the induced inhomogeneities correctly and more general image formation models are needed.
Problem Formulation:
The image formulation process is generally modeled with a function ƒ applied to an ideal intensity-uniform image U(x,y), resulting in the acquired image N(x,y). In digital X-ray images, the image degradation process dependency on the intensity values U(x,y) is relatively small compared to position dependent factors. Hence, we can rewrite equation (10) as follows
N ( x,y )=ƒ x,y ( U ( x,y ))
This equation can be simplified as
N ( x,y )= U ( x,y ) S M ( x,y )+ S A ( x,y )
where S M (x,y) and S A (x,y) represent the multiplicative and additive components of the image degradation process. To remove the image inhomogeneities, a corrected image Û is searched which optimally estimates the true image U. If the estimates Ŝ A and Ŝ M of the actual formation components S A and S M are available, the corrected image Û is given by the inverse of the image formation model
U
^
(
x
,
y
)
=
N
(
x
,
y
)
-
S
^
A
(
x
,
y
)
S
^
M
(
x
,
y
)
=
N
(
x
,
y
)
S
~
M
(
x
,
y
)
-
S
~
A
(
x
,
y
)
with
S ~ M ( x , y ) = 1 S ^ M ( x , y ) and S ~ A ( x , y ) = S ^ A ( x , y ) S ^ M ( x , y ) .
The problem of correcting the inhomogeneities is thus reformulated as the problem of estimating the additive and multiplicative components {tilde over (S)} A and {tilde over (S)} M .
Correction Strategy:
Finding the optimal parameters of the components {tilde over (S)} A and {tilde over (S)} M involves defining a criterion which has to be optimized. In this section, two criterions are defined.
One correction strategy (second embodiment of the method according to the present invention) is based on the assumption that the intensity values of the direct exposure area (also referred to as background) from the acquired image is Gaussian distributed. In ideal circumstances, this assumption is true for the acquired image N(x,y). The likelihood that a pixel μ i of the corrected image belongs to the background is
p
(
u
i
|
μ
,
σ
)
=
1
2
πσ
2
exp
(
-
1
2
(
u
i
-
μ
)
2
σ
2
)
(
12
)
where μ and σ 2 are the true mean and variance of the Gaussian distribution of the background pixels. Given an estimate {circumflex over (B)} of the direct exposure area, we seek to maximize the likelihood π i∈{circumflex over (B)} p(u i |μ,σ), which is equivalent to minimizing the log-likelihood
U
^
*
=
arg
min
B
^
,
U
^
-
Σ
i
∈
B
^
log
e
p
(
u
i
|
μ
,
σ
)
.
(
13
)
Another embodiment (third embodiment of the method of the present invention) is based on the assumption that the information content of the acquired image is higher than the information content of the uniform image, due to the added complexity of the imposed inhomogeneities:
I c ( N ( x,y ))= I c (ƒ x,y U ( x,y )))> I c ( U ( x,y ))
The information content I c can be directly expressed by the Shannon-Wiener entropy
I
c
(
N
(
x
,
y
)
)
=
H
(
N
(
x
,
y
)
)
=
-
∑
n
p
(
n
)
log
e
p
(
n
)
(
14
)
where p(n) is the probability than a, point in image N(x,y) has intensity value n. The optimal corrected image Û* is thus given by
U
^
*
=
arg
min
U
^
H
(
U
^
(
x
,
y
)
)
(
15
)
Method
Because the Heel effect is totally reduced in the collimation area and an estimate of the background {circumflex over (B)} is needed to optimize equation (13), a segmentation algorithm is presented.
In the next, implementation details of the correction models of the second and third embodiment of the method according to the present invention are given.
Image Segmentation
The boundaries of the collimation area have been found using the Hough transform, assuming that these are rectilinear edges as is the case for all hand radiographs in our database. To make this approach more robust, the contributions of each image point to the Hough accumulator are weighted by its gradient magnitude and, for each point, only the lines whose direction is within 10 degrees of the normal to the local gradient direction are considered. The 4 most salient points in Hough space that represent a quadragon with inner angles between 80 and 100 degrees are selected as candidate boundary of the collimation area. Because not all 4 collimation boundaries are always present in the image, candidate boundaries along which the image intensity differ from the expected intensity values for the collimation region, are rejected.
To extract the background region B, a seed fill algorithm is used that starts from the boundary of the collimation region as determined in the previous step. Appropriate seed points for B are found by considering a small band along each of the collimator edges and retaining all pixels whose intensity is smaller than the mean of the band. This approach avoids choosing pixels that belong to the diagnostic region as candidate seed pixels. The background region is then grown by considering all neighboring pixels n i ,i=1, . . . 8 of each pixel p∈{circumflex over (B)} and adding q i to {circumflex over (B)} if the intensity difference between p and q is smaller than some specified threshold.
Maximum Likelihood Estimation
We simplify (13), by leaving out the multiplicative component {tilde over (S)} M of the image degradation process
U
^
*
=
arg
min
B
^
,
U
^
-
∑
i
∈
B
^
log
e
p
(
u
i
|
μ
,
σ
)
=
arg
min
B
^
,
U
^
-
∑
x
,
y
∈
B
^
log
e
p
(
U
(
x
,
y
)
|
μ
,
σ
)
=
arg
min
B
^
,
U
^
-
∑
x
,
y
∈
B
^
log
e
p
(
N
(
x
,
y
)
-
S
~
A
(
x
,
y
)
|
μ
,
σ
)
(
16
)
This equation is optimized by iteratively estimating the background {circumflex over (B)} and finding parameters μ, σ and the components {tilde over (S)} A after differentiation and substitution of p(u i |μ,σ) by the Gaussian distribution (12). To find the solution for the multiplicative component, the same approach can be followed after logarithmic transforming the intensity values.
The initial estimate for the background B is taken from the segmentation algorithm described higher. All other estimates for B are computed using a histogram, based threshold algorithm. The threshold is defined as the smallest value of ε satisfying
ɛ
*
=
min
ɛ
⋂
i
=
1
,
2
,
3
{
ɛ
>
μ
+
σ
|
p
β
(
ɛ
β
)
<
p
β
(
ɛ
β
+
i
)
}
ɛ
β
=
[
ɛ
-
min
U
^
max
U
^
-
min
U
^
]
·
255
(
17
)
where p β (n) is the probability that a point in image Û β has value n and μ, σ are the mean and variance of the corrected pixels belonging to the previous background estimate.
The maximum likelihood estimates for the parameters μ and σ of 7, can be found by minimization of −Σ i log e p(u i |μ,σ). The egressions fir μ is given by the condition that
∂
∂
μ
(
-
∑
i
log
e
p
(
u
i
|
μ
,
σ
)
)
=
0.
Differentiating and substituting p(u,|μ,σ) by the Gaussian distribution (12) yields:
μ
=
∑
i
∈
B
^
u
i
n
=
∑
i
∈
B
^
N
(
x
i
,
y
i
)
-
S
~
A
(
x
i
,
y
i
)
n
where x i ,y i is the spatial position of pixel i and n is the number of background pixels. The same approach can be followed to derive the expression for σ:
σ
2
=
∑
i
∈
B
^
(
u
i
-
μ
)
2
n
=
∑
i
∈
B
^
(
N
(
x
i
,
y
i
)
-
μ
S
~
A
(
x
i
,
y
i
)
)
2
n
Suppose that the spatially smoothly varying component {tilde over (S)} A can be modeled by a linear combination of K polynomial basis functions φ j (x i ,y i )
u
i
=
N
(
x
i
,
y
i
)
-
∑
j
=
1
,
…
,
K
c
j
ϕ
j
(
x
i
,
y
i
)
the partial derivative for c k of (16) set to zero yields
∑
i
∈
B
^
[
N
(
x
i
,
y
i
)
-
μ
-
∑
j
c
j
ϕ
j
(
x
i
,
y
i
)
]
=
0
∀
k
.
Solving this equation for {c j } does not seem very tractable, but combining all equations for all k and introducing matrix notation simplifies the problem considerably
C
=
[
c
1
c
2
⋮
⋮
⋮
]
=
AR
(
18
)
where A represents the geometry of the image formation model, each of its rows evaluating one basis function φ k at all coordinates and R represents the residue image, i.e. the difference between the acquired image and the estimated background mean. In full matrix notation, the equation is
C
=
[
ϕ
1
(
x
1
)
ϕ
1
(
x
2
)
ϕ
1
(
x
3
)
⋯
ϕ
2
(
x
1
)
ϕ
2
(
x
2
)
ϕ
2
(
x
3
)
⋯
⋯
⋯
⋯
⋯
⋯
⋯
⋯
⋯
⋯
⋯
⋯
⋯
]
[
n
1
-
μ
n
2
-
μ
⋯
⋯
⋯
]
where n i is the intensity value of the acquired image at pixel (x i ,y i ). Equation (18) is a least squares fit to the residue image. As least squares fit are sensitive to outliers, only entries in R which satisfy |n i −μ|<2.5 σ are included to solve (18).
Entropy Minimization
Suppose than the image degradation components {tilde over (S)} A and {tilde over (S)} M can be modeled by a linear combination of K polynomial bass functions φ j m,α (x,y)
S
~
M
(
x
i
,
y
i
)
=
∑
j
=
1
,
…
,
K
m
m
j
ϕ
j
m
(
x
i
,
y
i
)
S
~
A
(
x
i
,
y
i
)
=
∑
j
=
1
,
…
,
K
m
a
j
ϕ
j
a
(
x
i
,
y
i
)
Equation (15) is reformulated as
{
a
*
,
m
*
}
=
arg
min
a
,
m
{
H
(
N
(
x
,
y
)
S
~
M
(
x
,
y
)
-
S
~
A
(
x
,
y
)
)
}
(
19
)
The optimal additive parameters α* and multiplicative parameters m* are found by Powell's multidimensional directional set method and Brent's one-dimensional optimization algorithm (W. H. Press, S. A. Teukosky, W. T. Vetterling, and B. P. Flannery. Numerical Recipes in C. Cambridge University Press, 1992.)
The set of probabilities p(n) in (14) can be obtained by normalization of its histogram. In order to reduce the influence or random, effects induced by discretizing the histogram, we use partial intensity interpolation at histogram formation. When transforming the image, an integer intensity value g is transformed to a real value g′, which in general lies between two integer values k and k+1. The histogram sentries h(k) and h(k+1) are updated by k+1−g′ and g′−k respectively, To obtain a smoother decline to the absolute minimum and to minimize the effects of local minima, the obtained histogram is blurred to:
h
^
(
n
)
=
∑
i
=
-
t
t
h
(
n
+
i
)
(
t
+
1
-
i
)
where the parameter t was set to 3.
Image Formation Models
We have tested different image formation models which are summarized in, Table 1. The polynomial models are defined as
ϕ
v
=
c
0
+
c
1
x
+
c
2
y
+
c
3
x
2
+
c
4
xy
+
c
5
y
2
+
…
+
c
(
v
+
2
)
!
2
!
v
!
y
v
Model Σ i ,i=1,2 are included for the maximal likelihood estimation, model Σ 3 is the general image formation model while model Σ 4 is derived from (2). Model Σ 5 is approximation of model Σ 4 where the different model parameters are substituted with real values and higher orders are discarded where appropriate. Model Σ 6 is included for resemblance with model Σ 2 .
TABLE 1
Image formation models used for correction of inhomogeneities.
φ v is a polynomial model of order v.
Model
Correction
∑
1
v
Û = N · φ v
∑
2
v
Û = N + φ v
∑
3
v
Û = N · φ 1 v + φ 2 v
∑
4
v
U
^
=
N
·
exp
(
ϕ
1
v
ϕ
2
v
-
1
)
∑
5
v
U
^
=
N
·
ϕ
1
v
ϕ
2
v
-
1
∑
6
v
U
^
=
N
+
ϕ
1
v
ϕ
2
v
-
1
Fourth Embodiment
In a fourth embodiment according to the present invention, a statistical mixture model of the image is generated based on a plurality of K image regions.
Each of these regions or classes may physically correspond to e.g. bone, soft tissue and direct exposure area.
In the assumption or a normal mixture model, each class is represented by three unknown parameters: the proportion π k of image pixels, the mean value μ k and the variance σ k 2 .
The set ψ collectively comprising all unknown parameters becomes:
ψ={π 1 , . . . ,π K ,μ 1 , . . . ,μ K ,σ 1 2 , . . . ,σ K 2 }
The subset of parameters pertaining to class k is denoted as
ψ k ={π k ,μ k ,σ k 2 }
The image intensity histogram, de-noting the probability distribution that a pixel i has intensity y i is therefore a Gaussian mixture model
f ( y i | ψ ) = ∑ k = 1 K π k f k ( y i | ψ k ) = ∑ k = 1 K π k 1 2 πσ k 2 exp ( - ( y i - μ k ) 2 2 σ k 2 ) i = 1 , … , N
The Basic EM Algorithm
The classical analytical method to estimate the parameter ψ is to maximise the log-likelihood function for each of then parameters to estimate.
The maximum likelihood estimates of each parameter can be solved from a system of equations which is non-linear in general and hence requires methods such as Newton-Raphson algorithm.
The Expectation-Maximisation (EM) algorithm estimates the parameters ψ by adding segmentation labels z i (i represents pixel i and z i has a value k, k=1 . . . K), (so called non-observable data) to each of the grey values y i of the pixels (so called observable data).
In each iteration of the EM algorithm the expectation step (E-step) estimates a segmentation label k to each pixel i on the basis of parameter values ψ from the previous iteration and in the maximisation step (M-step) new parameter values ψ are computed on the basis of maximum likelihood, given the new segmentation labels associated with each of the newly assigned segmentation labels.
The Extended EM Algorithm
In the context of the present invention two modifications have been added to the EM algorithm to make it correcting for a bias field caused by global inhomogeneities in the imaging chain and to discard outliers due to local inhomogeneities.
The global inhomogeneities in the image distort the assumed normal distribution of the pixel classes.
Every pixel segmentation class is modelled as a normal distribution of which a sum of spatially correlated continuous basis functions is subtracted.
Examples of such basis functions are orthogonal polynomials. Other orthogonal continuous functions may be used as well.
The coefficients of the basis polynomials are added to the parameter set ψ which must be estimated
ψ
=
{
π
1
,
…
,
π
K
,
μ
1
,
…
,
μ
K
,
σ
1
2
,
…
,
σ
K
2
,
C
}
=
{
π
1
,
…
,
π
K
,
μ
1
,
…
,
μ
K
,
σ
1
2
,
…
,
σ
K
2
,
c
1
,
…
,
c
R
}
with the probability distribution for the pixels belonging to segmentation class k
f
k
(
y
|
Ψ
k
C
)
=
1
2
πσ
k
2
exp
[
-
1
2
σ
k
2
(
y
-
μ
k
-
∑
r
=
t
R
c
r
Φ
r
)
2
]
k
=
1
,
…
,
K
with φ r a N×1 vector holding the polynomial function evaluation for the r-th basis polynomial at pixel location i (i=1, . . . N).
A further correction to the basic EM algorithm is to make it robust against outliers in the observed distribution of a segmentation class, caused by the presence of local defects (dust, scratch, pixel drop out . . . ) in the recording member, said defects not being attributable to the global inhomogeneities.
To this purpose each pixel class k is divided in a Gaussian class (which is distributed by the inhomogeneity and which is corrected by the bias function) and a rejection class. This rejection class is assumed to have a uniform distribution with probability density δ k and contains a proportion ε∈[0,1] of the pixels. The probability distribution of pixel class k is therefore
ƒ kε ( y i |ψ k )=(1−ε)ƒ k ( y i |ψ k )+εδ k
Summary of the Extended EM Algorithm
The extended EM algorithm is summarised by the following formulas valid for iteration m:
E-Step:
For each pixel class k, k=1, . . . K and each pixel i, i=1, . . . N, compute
p
ik
(
m
+
1
)
=
f
k
(
y
i
|
ψ
k
(
m
)
)
π
k
(
m
)
∑
i
=
1
K
f
i
(
y
i
|
ψ
k
(
m
)
)
π
i
(
m
)
λ
k
(
m
+
1
)
=
1
2
πσ
k
2
exp
(
-
1
2
κ
2
)
t
ik
(
m
+
1
)
=
f
k
(
y
i
|
ψ
k
(
m
)
)
f
i
(
y
i
|
ψ
k
(
m
)
)
+
λ
k
(
m
+
1
)
with
y i denoting the intensity values of pixel i
ψ k (m) the set of statistical parameter describing class k at iteration m
ψ k (m) the proportion of pixels in the image belonging to class k at iteration m
ƒ k the probability density function of intensity of pixels of class k denoting the conditional probability that pixel i has gray value y i given parameters ψ k of class k
p ik (m+1) the probability that pixel i belongs to class k at iteration m+1, these probabilities sum to 1, i.e.
∑
k
=
1
K
p
ik
(
m
+
1
)
=
1.
σ k 2(m) the variance of intensity of pixels belonging to class k at iteration m,
k, a threshold on the Mahalanobis distance defined as
d
k
=
(
y
i
-
μ
k
)
σ
k
λ k (m+1) the probability of pixels of class k being outliers,
t ik ( m + 1 )
the probability of pixels inside class k to belong to the non-rejected group (i.e. not being an outlier). Because λ k ≠0, this probability may be less than one, and hence
∑
k
=
1
K
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
≤
1.
At this stage, a segmentation of the image could be obtained by a hard classification, i.e. each pixel i is assigned class k for which p ik (m+1) is maximal, i.e. class pixel
i = argmax k { p ik ( m + 1 ) } .
In the sequel of the EM algorithm, soft classification labels p ik (m+1) E[0 . . . 1] are used.
M-Step
For each class k=1 . . . K and for each coefficient c r , r=1 . . . R applied to the corresponding polynomial basis function, compute
π
k
(
m
+
1
)
=
∑
i
=
1
N
p
ik
(
m
+
1
)
N
μ
k
(
m
+
1
)
=
∑
i
=
1
N
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
(
y
i
-
∑
r
=
1
R
c
r
(
m
)
φ
ir
)
∑
i
=
1
N
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
σ
k
2
(
m
+
1
)
=
∑
i
=
1
N
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
(
y
i
-
μ
k
(
m
+
1
)
-
∑
r
=
1
R
c
r
(
m
)
φ
ir
)
2
∑
i
=
1
N
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
C
(
m
+
1
)
=
[
c
1
(
m
+
1
)
c
2
(
m
+
1
)
…
c
R
(
m
+
1
)
]
=
(
A
T
W
(
m
+
1
)
A
)
-
1
A
T
W
(
m
+
1
)
R
(
m
+
1
)
with
A
=
[
φ
11
φ
12
…
φ
1
R
φ
21
…
…
…
…
…
φ
N1
…
…
φ
NR
]
W
(
m
+
1
)
=
[
w
1
(
m
+
1
)
0
…
0
0
w
2
(
m
+
1
)
…
…
…
0
0
…
0
w
N
(
m
+
1
)
]
,
w
i
(
m
+
1
)
=
∑
k
=
1
K
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
σ
k
2
(
m
+
1
)
R
(
m
+
1
)
=
[
y
1
-
y
~
1
(
m
+
1
)
y
2
-
y
~
2
(
m
+
1
)
…
y
N
-
y
~
N
(
m
+
1
)
]
,
y
~
i
(
m
+
1
)
=
∑
k
=
1
K
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
σ
k
2
(
m
+
1
)
μ
k
2
(
m
+
1
)
∑
k
=
1
K
p
ik
(
m
+
1
)
t
ik
(
m
+
1
)
σ
k
2
(
m
+
1
)
wherein
μ k (m+1) denotes the mean intensity value of pixels belonging to class k at iteration (m+1),
σ k 2(m+1) denotes the variance of intensity value of pixels belonging to class k at iteration (m+1), after having corrected for the estimate of the bias field,
C (m+1) is a vector containing coefficients c r , r=1 . . . R applied to the corresponding polynomial basis function,
A(i,r)=φ ir is the evaluation of the M-th polynomial basis function at pixel location i (matrix A thus represents the geometry of the bias field model),
W (m+1) is a diagonal matrix of weights w i (m+1) , i=1 . . . N, with
w i (m+1) the weight applied at pixel i in iteration (m+1). Said weight is the sum of the inverse of variance overall classes k, k=1 . . . K, each weighted with the probability of that class which is p ik (m+1) t ik (m+1) .
R (m+1) is a residue image, the residue being the difference between the original image matrix y i , i=1 . . . N and the corrected image matrix {tilde over (y)} i (m+1) at iteration (m+1).
The equations of the extended EM algorithm reduce to the basic EM algorithm when no bias correction is performed (all c r =0) or no outliers are taken into account (all λ k =0 and hence all t ik =1).
Initialization
In order to start the iterations of the EM algorithm, an initial estimate ψ(0) for the parameter set ψ is needed.
This is achieved by assigning each pixel i, i=1 . . . N, to one of the classes k=1 . . . K on the basis of intensity histogram slicing.
This assignment involves the computation of p ik (0) , which is a hard assignment of probability 1 to one of the k possible class probabilities at pixel i and putting all other probabilities no zero.
Furthermore, no outliers are assumed during initialisation, i.e. t tk (0) =1 for all i.
Therefore the M-step in which the values ψ are computed can be executed immediately after initialisation.
Therefore the initialisation on step for which the iteration value m=0 does not present a true iteration step in the EM algorithm.
To slice the histogram into K distinct initial pixel classes k=1 . . . K, prior art techniques are used. In the context of the present invention, the histogram is smoothed and approximated with a higher order polynomial, after which the two or three most important maxima are determined. The intensity thresholds separating intensities of different classes are then determined as the intensities corresponding to the minima between these different maxima. | Several methods for retrospective correction of intensity inhomogeneities in digital diagnostic radiation images are presented. The methods are based on the correction of a digital image representation by means of a bias field. The bias field is deduced from the digital image representation of the diagnostic radiation image. | 6 |
BACKGROUND OF THE INVENTION
This is a division of application Ser. No. 837,052, filed Sept. 28, 1977 now U.S. Pat. No. 4,137,968, which is a Continuation-In-Part of our prior application Ser. No. 669,127, filed Mar. 22, 1976, now U.S. Pat. No. 4,079,784.
Great improvements in oil recovery are necessary to satisfy the present and future energy requirements of the United States. Thus, improvements are needed in the field of enhanced thermal recovery, such as an improved in situ combustion ignition system for use in heavy oils, tar sands, and oil shale, particularly in deep wells.
Various types of ignition systems have been used and are in use for in situ combustion ignition. Electrical heaters have been used extensively but are limited to 3000 ft or less due to the problem of supplying adequate electrical power to greater depths. The use of gas burning ignition systems becomes more difficult with depth because most designs include a multiplicity of air and gas conduits and electrical cables which complexes the placement of the systems as the depth becomes greater. A recently developed catalytic heater utilizes only a wireline for placement, but has the disadvantage of operating without a temperature monitoring system. Some gas ignition systems have the disadvantage of requiring complete removal from the well and re-running if flameout occurs. This becomes very expensive in rig time alone.
OBJECTS OF THE INVENTION
It is therefore a primary object of this invention to present an ignition system which alleviates these disadvantages and provides an elaborate control system not heretofore practiced in the art.
Another primary object of this invention is to provide a method for assembling a downhole burner for an in situ combustion operation to recover petroleum from a well in a subterranean reservoir including particularly the step of interconnecting power means with both an ignitor in the burner and the thermocouple adjacent thereto for automatically energizing the ignitor for igniting the air-fuel combustion mixture in the burner when no combustion is occurring and for automatically de-energizing the ignitor when combustion is occurring in the burner for forming a reliable flame-out proof burner.
Accordingly another primary object of this invention is to provide ignition system in a burner for initiating in situ combustion to recover petroleum from a hydrocarbon containing subterranean reservoir in which an air-fuel mixture in the burner having an ignitor and a thermocouple adjacent thereto is ignited when the thermocouple indicates no combustion and the ignitor is extinguished when the thermocouple indicates burning in a combustion chamber to provide a reliable and flame-out proof burner for in situ combustion deep in the well.
A further object of this invention is to provide a downhole automatic burner for an in situ combustion operation deep in a well that is easy to operate, is of simple configuration, is economical to build and assemble, and is of greater efficiency for the recovery of petroleum from the well in a subterranean reservoir.
Other objects and various advantages of the disclosed method for assembling a downhole burner and a new burner for heating or for in situ combustion to recover petroleum will be apparent from the following detailed description, together with the accompanying drawings, submitted for purposes of illustration only and not intended to define the scope of the invention, reference being had for that purpose to the subjoined claims.
BRIEF DESCRIPTION OF THE INVENTION
The drawings diagrammatically illustrate by way of example, not by way of limitation, one form of the invention.
FIG. 1 is a schematic sectional view of the downhole burner for an in situ combustion operation to recover petroleum from a well in a subterranean reservoir for illustrating a burner assemblied by the new method;
FIG. 2A is a schematic sectional view of the upper portion of the downhole burner;
FIG. 2B is a schematic sectional view of the lower portion of the downhole burner;
FIG. 3 is a section taken at 3--3 of FIG. 2B; and
FIG. 4 is a schematic block diagram of the electronics required to ignite and monitor the in situ combustion.
The invention disclosed herein, the scope of which being defined in the appended claims, is not limited in its application to the details of construction and arrangement of parts shown and described for carrying out the disclosed method, since the invention is capable of other embodiments for being assemblied by other methods and of being practiced or carried out in various other ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Further, many modifications and variations of the invention as hereinbefore set forth will occur to those skilled in the art. Therefore, all such modifications and variations which are within the spirit and scope of the invention herein are included and only such limitations should be imposed as are indicated in the appended claims.
DESCRIPTION OF THE INVENTION
This invention comprises a method for assembling a downhole burner for an in situ combustion operation to recover petroleum from a well in a subterranean reservoir, and a mechanism assembled by the method and for being assembled by the other methods.
METHOD FOR ASSEMBLING AN AUTOMATIC DOWNHOLE BURNER TO RECOVER PETROLEUM
A method for assembling a downhole burner for heating or for an in situ combustion operation to recover petroleum from a well in a subterranean reservoir comprises:
(1) forming an elongated combustion chamber open at both ends,
(2) mounting an ignitor in the combustion chamber intermediate the ends thereof,
(3) forming orifices in the walls of a thick walled cylinder connected to the upper portion of the combustion chamber,
(4) extending a downhole fuel supply conduit through the thick walled cylinder down to the open upper end of the elongated combustion chamber,
(5) extending a tubing over the thick walled cylinder and fuel supply conduit and connecting said tubing to the lower portion of said thick walled cylinder for forming a downhole primary air supply annulus for the combustion chamber,
(6) forming a secondary air supply annulus between the tubing and the well casing for supplying heat to the reservoir,
(7) mounting at least one thermocouple in the upper portion of the combustion chamber for sensing excessive heat in the combustion chamber upper portion,
(8) mounting at least one thermocouple in the combustion chamber adjacent the ignitor for detecting whether an air-fuel mixture in the combustion chamber is ignited or not ignited, and
(9) interconnecting power means with both the ignitor and the thermocouple for energizing the ignitor for igniting the air-fuel mixture in the combustion chamber when no combustion is occurring and for de-energizing the ignitor when combustion is occurring in the air-fuel combustion chamber for providing a reliable and flame-out proof burner for in situ combustion deep in a well.
The above basic method may likewise include the following additional steps:
(10) passing the electrical conduits through the walls of the thick walled air inlet cylinder and embedding the electrical conduits in the walls of the fuel supply conduit;
(11) forming a plurality of transverse air ducts in the elongated cylindrical thick walled cylinder for forming a downhole air supply annulus around the fuel supply conduit for passage of air from the downhole air supply annulus to the air-fuel combustion chamber for ensuring a highly agitated combustion mixture, and
(12) forming the connection between the downhole air supply annulus and the combustion chamber in a detachable connection for being sealed and unsealed.
A DOWNHOLE BURNER FOR HEATING OR FOR INITIATING IN SITU COMBUSTION TO RECOVER PETROLEUM
A downhole burner is disclosed for being assembled by the above method.
While various devices may be utilized for carrying out or practicing the inventive methods and for being assembled by the above methods, FIGS. 1 and 2 illustrate at least one inventive apparatus for practicing the methods described above.
This gas fired burner 10 is illustrated schematically in FIGS. 1, and in more details in FIGS. 2A and 2B in cross section as being suspended from hollow cable 11, FIGS. 1 and 2A, in the well tubing 13, FIGS. 1 and 2B, the well tubing being centered in and spaced from the well casing 33, with spacers 50, FIG. 1. The gas burner 10 comprises a combustion chamber 14, an air inlet cylinder 19, FIGS. 1 and 2B and an electrical chamber 15, FIGS. 1 and 2A, having an ignitor relay 16, FIG. 2A, and a hollow cable-electrical and natural gas connecting chamber 17, FIGS. 1 and 2A.
Well tubing 13, FIG. 1 is centered in the well casing 33 with the spacers 50, only two spacers or centralizers being shown for clarity of disclosure. A pump seating nipple 12, FIGS. 1 and 2B, is formed on the internal surface of the well tubing 13 for supporting a liquid pump for producing crude oil, as in a reverse or counter-current flow well, for example. After flow of all liquid petroleum has ceased and heat is desired to reduce the viscosity of the remaining petroleum for increased flow for increased production the pump is removed and the gas fired burner 10 lowered into well tubing 13 to rest on the pump seating nipple 12 or the lower end of the air inlet cylinder. Seals are provided between a reduced diameter portion 18, FIGS. 1 and 2B, of the thick walled air inlet cylinder 19, such as, but not limited to, o-rings 21a, 21b.
Hollow cable 11, FIG. 1, centered in well tubing 13 forms a primay downhole of combustion air supply annulus duct 51. Well tubing 13 centered in well casing 33 forms a secondary air supply annulus duct 52 in which air is pumped down from the surface in annulus 52 for being heated by the flame 53. Hollow cable 11 per se forms the fuel natural gas supply duct, a fuel supply duct 24 illustrated in FIGS. 2A and 2B being deleted in FIG. 1 for clarity of disclosure.
FIGS. 2A and 2B, enlarged vertical sectional schematic views of the burner 10, provide more details thereof. The combustion chamber 14, FIG. 2B, comprises a hollow, open-ended cylinder sheath (such as a ceramic sheath) with one end fitted over the reduced diameter portion 18 of a thick walled air inlet cylinder 19 and secured thereto with pins 20, or the like. The reduced diameter portion 18 fits down inside the pump seating nipple until the burner comes to rest on the beveled portion where the diameter of the thick walled air inlet cylinder 19 increases to full size. An ignitor 22 shown schematically in FIG. 1, actually comprises three nicrome wire heater elements connected in delta as illustrated in FIGS. 3 and 4. Connected to the three intersections of each of the three elements of the ignitor are wires 23a, 23b and 23c, each wire being in an electrical insulator 26a, 26b and 26c, respectively, FIG. 3. All three insulators and their respective wires are mounted in the end of the cylinder reduced diameter portion 18, FIG. 2B, which extends internally of the combustion chamber ceramic sheath 14. The wires 23a, 23b and 23c, pass up through the thick walled cylinder, through the relay 16, FIG. 2A in the electrical chamber 15, through the hollow cable-electrical and natural gas connecting chamber 17, and into the walls of the insulated wire sheathed hollow cable 11 as electrical wires 25 to the surface where they are connected to the burner ignitor control system disclosed hereinafter. The hollow cable 11 is a reelable armored type hose having an armor-wire outer covering, a coiled-spring inner wall stiffener, and at least three separately insulated electrical conductors embedded between two layers of impervious plastic material forming the walls of the hose, such as, but not limited to assignee's U.S. Pat. No. 3,800,870. This hose or cable is capable of withstanding high pressure, particularly in its use of supplying natural gas, or the like, from the surface down to the combustion chamber. Thus the cable carries the necessary electrical wiring for the ignitor and the thermocouples.
Natural gas is supplied directly to the combustion chamber 14, FIGS. 1 and 2B, at the location of the ignitor heater 22 from the gas supply tube or fuel supply conduit 24, FIG. 2B, which extends down through the burner 10 and the hollow cable 11 from a suitable supply (not shown) at the surface.
Primary air for the gas fired burner 10, FIGS. 1 and 2B is pumped down in the primary air annulus or primary air supply conduit 51 formed between the well tubing or air supply tube 13 and the hollow cable 11. As this pressurized air, arrives at the top of the thick walled air inlet cylinder 19, it passes through transverse and downwardly sloping orifices or air inlet ports 27a, 27b and 27c, FIG. 2B, to a large axial cylindrical duct 28 in the air inlet cylinder 19. This duct 28 has the fuel supply tube 24, FIG. 2B, mounted in the center thereof as it traverses the full length of the air inlet cylinder 19 from which the fuel supply length of the air inlet cylinder 19 from which the fuel supply tube protrudes a substantial distance to eject the natural gas into the ignitor heater 22. The air from the inlet ports 27a, 27b and 27c, FIG. 2B, empties into the duct 28 or annulus formed therein by the centered fuel supply conduit 24. The pressurized air from these ports if forced down the annulus and, expands into combustion chamber 14 while mixing with the natural gas at ignitor heater 22, FIGS. 1 and 2B, thereby providing a combustible mixture.
A thermocouple support tube 29, FIG. 2B, extends downwardly from the lower end of the air inlet cylinder 19 close to and past the ignitor heater 22. One thermocouple 30 is mounted on thermocouple support tube 29 below the ignitor heater 22 at the end of the support tube and a second thermocouple 31 is mounted on the thermocouple support tube at the base of the tube adjacent the air inlet cylinder 19. Wires 32a, 32b and 32c, FIG. 4, from the two thermocouples 30 and 31 pass up to the relay 16 of the burner 10. From the relay 16, wires L 1 , L 2 and L 3 extend to control relay 35 at the surface.
FIG. 3 is a sectional view at 3--3 on FIG. 2B illustrating the ignitor heater 22 and thermocouple 30 mounted on thermocouple support tube 29 in the combustion chamber ceramic sheath 17.
FIG. 4 illustrates schematically the electrical system for the burner ignition system. Three conductors in the wall of the hollow cable provide current for ignition of the burner followed by temperature monitoring of the burner after ignition has been sustained.
More specifically, a three phase electrical power source 34, FIG. 4, having 3 output leads 23a, 23b and 23c supplies 208 volt ac 3-phrase current, for example, to the three wires L 1 , L 2 and L 3 respectively in the walls of the hollow gas supply cable 11 through relay 35 having three, 3 pole, double throw, latching switches 36, 37 and 38.
Relays 16 and 35, FIG. 4, are current pulse activated step relays, such as but not limited to, the series 50 manufactured by Ledex Inc. of Dayton, Ohio 45402. Capacitor c is discharged through the relay coils when push button switch 44 is pressed. Latching switches 36, 37 and 38 of step relay 35 switches electrical lines L 1 , L 2 and L 3 between the heater wires 23a, 23b and 23c, respectively, and the recorder wires 32a, 32b and 32c, respectively. Cable 11 is lowered over pulley 39, for example, into the well to the desired depth as indicated by the depth indicator 40 and the pump seating nipple 12, FIG. 2B. Relay 35 FIG. 4, is connected in parallel with relay 16. Relay 16 down in the burner likewise is illustrated on FIG. 4 a having latching switches 41, 42 and 43, for connecting wires L 1 , L 2 and L 3 respectively, to either the nicrome wire heater 22 through wires 23a, 23b and 23 c or to the two thermocouples 30 and 31 through wires 32a, 32b and 32c. Recorders 45 and 46 show instant readouts of the temperatures encountered in the burner 10. Manual push button switch 44 thus may connect the electrical power 34 to the ignitor heater 22 with the relays 16 and 35 set as illustrated in FIG. 4, or it may connect the recorders 45, 46 to the thermocouples 30 and 31, by actuation of the relays to their other position. Thermocouple 30 detects the temperature of the flame below the ignitor while thermocouple 31 detects the temperature of the upper portion of the rest of the ignitor sensitive to excessive heat. This manual operation is disclosed in greater detail in our copending patent application Ser. No. 669,127, filed Mar. 22, 1976 now U.S. Pat. No. 4,079,784, issued Mar. 21, 1978.
Briefly, in manual operation, for introducing heat to the formation in order to reduce the viscosity of the petroleum so that it will flow more readily for recovery, the burner 10 is lowered down into the well to rest on the pump seating nipple 12, FIG. 2B, and to be sealed therein by o-rings 21a, 21b. Natural gas is pumped down at a predetermined pressure through the hollow cable 11 to the combustion chamber 14 while the precise amount of primary air is pumped down the annulus around the hollow cable to inside the combustion chamber to provide an explosive mixture therein. Power source 34, FIG. 4, also at the surface, is then actuated with the manual push button switch 44 (not shown actuated yet) and relays 35 and 16 set as illustrated in FIG. 4, to activate the heater ignitor wire coil element 22 for a few seconds to ignite the combustion mixture in the combustion chamber 14, FIG. 2B, deep in the well. After a sufficient time period has lapsed to ensure ignition of the burner 10, push button switch 44 is released to the position illustrated in FIG. 4. Instantly relays 35 and 16 flip their respective three switches to the other position from that illustrated on FIG. 4 to thereby disconnect the power source 34 from the ignitor 22 and to interconnect the temperature recorders 45 and 46 with their respective thermocouples 30 and 31.
After the heater is lighted deep in the well, additional air is required to heat the formation or reservoir. This additional air is pumped down from the surface in larger annulus or secondary air supply conduit annulus 52, FIG. 1 formed between the well tubing 13 and the well casing 33. As this air passes down and around the full length of the heater 14 and a portion of the flame, it becomes very hot. This heated air is then transferred to the formation interval, as illustrated on FIG. 1, and in due course with continued burning, in situ combustion results and is contained for as long as desired.
Recorder 45 would then be indicating the temperature of combustion in the combustion chamber and recorder 46 would be indicating the temperature at which the upper portion of the burner is being exposed to, as the vulnerable electronic equipment therein. When the combustion chamber temperature drops below combustion temperature, a flame-out is indicated immediately and after it is determined that the gas and air supplies are adequate, then the switch 44, FIG. 4, is manually actuated or pushed to flip both relays 35 and 16 and their respective 3 switches each to disconnect the recorders 45 and 46 from the thermocouples 30, 31 and to interconnect the power source 34 with the ignitor 22 to relight the burner. After adequate time has lapsed for ignition, push-button switch 44 releases.
Automatic operation of the ignitor 22 occurs as follows. Amplifier 47, FIG. 4, sends a signal to limit set 48. This electronics samples the signals from thermocouple 30. If the signal indicates that the fire is out or the temperature is less than set, a signal will go to the time module 49. The output signal from the timer module 49 will send a signal to the electronic switch 34. The signal sent from timer 49 will exist and the ignitor 22 energized for a suitable period of time, then revert back to a sample mode and remain until smaller temperature sample can be taken. If at that time the heat has not risen to within limits set on timer 48, timer 49 will repeat its cycle.
The electronic switch 54, FIG. 4 electronically by-passes the manual push button switch 44. If too high a temperature is recorded on recorder 46 from thermocouple 31 indicating the electrical portion of the burner may be approaching a too high or critical temperature, the air velocity in secondary air annulus 51, FIGS. 1 and 4 may be automatically increased for cooling of the burner.
This increase in secondary air flow is accomplished by Amplifier 55, FIG. 4, transmitting signals from temperature Recorder 2, or 46 to limit set 56. A temperature that is above the set limit is detected and annulus control valve 57 causes compressor 58 to force more air down secondary air annulus 52, FIGS. 1 and 4.
As an improved modification, automatic operation as also illustrated in FIG. 4 is obtained by the manual switch 44 being by-passed by electronic switch 54 which is responsive to a predetermined low temperature in thermocouple 30 for switching power to the ignitor burner for a predetermined period of time as explained in greater detail hereinbefore. Similarly secondary air and fuel is automatically increased for cooling when thermocouple 31, FIGS. 2B and 4, senses too high a temperature.
Obviously other methods may be utilized for heating and for initiating in situ combustion and other embodiments than that of FIGS. 1 and 4 may be utilized, depending on the particular subsurface lithology or petrography at the various depths.
Accordingly, it will be seen that the production of hydrocarbons from a subterranean hydrocarbon-bearing formation is stimulated by the burner formed by the above method and by the above downhole burner, and the disclosed burner will operate in a manner which meets each of the objects set forth hereinbefore.
While only one basic method of the invention and one mechanism formed thereby have been disclosed, it will be evident that various other methods and modifications are possible in the arrangement and construction of the disclosed methods and systems without departing from the scope of the invention and it is accordingly desired to comprehend within the purview of this invention such modifications as may be considered to fall within the scope of the appended claims. | A method for assembling an ignition system for in situ combustion operation to recover petroleum from a well in a subterranean reservoir, and an ignition system for an elongated combustion chamber suspended from a hollow electrical cable and which cable supplies both electrical means and fuel gas to the chamber. Air inlet ducts in the walls of the air inlet cylinder receive air from the annular space between the hollow cable and the wellbore tubing. An electrical ignitor is temporarily energized automatically or responsive to a thermocouple detecting no burning in the combustion chamber to ignite the fuel-air mixture in the combustion chamber. The ignitor is responsive to the thermocouple detecting burning in the combustion chamber for extinguishing the ignitor. The thermocouple is thus responsive to a flameout for re-energizing the ignitor either manually or automatically such that burner operation is interrupted only momentarily.
This new method includes further the steps of electrically connecting a second thermocouple to a limit set means and forming it responsive to the thermocouple for causing the flow of additional secondary air to be automatically increased to cool the electronics portion of the burner if the temperature therein goes beyond safe limits. | 4 |
CLAIM OF PRIORITY
[0001] This application claims priority from U.S. provisional patent application No. 60/230,071 entitled “DATA LIST TRANSMUTATION AND INPUT MAPPING,” filed Aug. 31, 2000, incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to the facilitation of the transfer of information over limited bandwidth networks, particularly wireless networks, and specifically to the transfer and presentation of information formatted for display on wireless Internet devices.
BACKGROUND
[0003] Currently, a number of different technologies seek to provide the benefits of the Internet, and the World Wide Web in particular, to users any time and anywhere they desire it through wireless technologies. However, both the wireless devices used to access the Internet and the networks which carry information to those devices have limitations.
[0004] Wireless devices are significantly smaller and less powerful than desktop or laptop devices which provide more conventional access to the World Wide Web via a web browser. The wireless networks which connect these devices to the Internet do not have the same bandwidth as land-based “wire line” systems, and provide this limited bandwidth at a higher cost, more limited availability and lower quality of service when compared with land-based systems.
[0005] One wireless application solution which is gaining popularity is wireless application protocol (WAP). WAP is a standard for bringing together wireless telephones and Internet content services regardless of the wireless network architecture or device type. WAP is designed to work with any type of underlying wireless network architecture, thereby freeing the provider to concentrate on the wireless application itself. As shown in FIG. 1, the WAP model presupposes a user agent 10 , such as a cellular telephone or personal digital assistant (PDA), which is equipped with a micro browser. The WAP client 10 communicates directly with a server on the Internet 25 via a WAP gateway 20 as shown in FIG. 1. The WAP gateway server sits between a wireless carrier's network 15 on one side and the public Internet 25 on the other. (This configuration need not be limited to the public Internet, but may include private Intranets, so that gateways can be located within the carrier or corporate firewalls or both.) The WAP server 20 handles the interface between the two sets of network protocols, wireless WAP and wireline TCP/IP. The WAP gateway server decodes and decompresses wireless terminal requests and sends it on to the appropriate web server as an ordinary HTTP request.
[0006] Certain wireless carriers have already implemented WAP gateways. If a standard HTML document is served in response to an HTTP request from a PDA 10 , the WAP gateway server implements content translation before the request can be relayed back to the WAP client 10 . The WAP gateway 20 also imposes data quantity limits on client responses. The gateway limitation means that for each given transaction, only a limited number of bytes may pass through the gateway. This so-called “gateway limit” defines the actual amount of data which may be returned in response to an HTTP request.
[0007] Generally, the WAP gateways impose some form of data limitation on the amount of data which is transmitted to the client 10 . In one case, the gateway limitation is at or about 1.5 Kbytes (or about 1492 bytes). Hence, this presents an additional problem to content providers to design pages and applications which can provide useful content and information to a WAP client 10 .
[0008] In addition to bandwidth limitations, device limitations present issues to content providers. The small screens of wireless devices mean display area is at a premium. In particular, the available display area of a wireless phone is limited to 4-10 lines, making the display of large amounts of data difficult. One technique used to address this issue is to allow a user to scroll the display up and down the page displayed on the device, in order to allow more information to be accessible to the user at a given time. Yet another limitation of such devices is the limited input/output mechanisms of such devices. Cell phones are limited to a keypad and a few additional control buttons. Hand-held PDA devices have small keyboards or pen-based input which requires input controls be placed on the screen. Even where a PDA or in some cases a pager has a full keyboard (i.e. the Blackberry™ wireless pager developed by Research In Motion, Waterloo Ontario, Canada), the size of such input devices means such input devices are not as functional as full-size keyboards.
[0009] In other types of devices where only a limited input mechanism is available, data organization and function mapping to limited inputs are known. For example, the mapping of letters of the alphabet to keypad numbers to input alphabetic characters into phone memory in, for example, cell phones is well known. Mapping other input functions to a device's limited input keys is known as well.
[0010] For example, the Startac® organizer manufactured by Motorola, Inc. is a PDA device which is designed to clip onto a cellular phone and interact with the phone. The organizer contains contact, calendering and notes information, and because of its size it is limited to four input buttons.
[0011] Content information in the organizer is organized alphabetically by an alphabetical tag similar to a paper telephone address book, with each entry alphabetized in accordance with its rules of display in a “display name” field. The user may then select individual tabs using the control buttons which identify further levels of granularity in the alphabetization. For example, the opening screen lists a set of tabs, each tab containing three letters (e.g. “ABC,” “DEF,” etc.) representing the first letter of the last name of each contact. Selecting “ABC” yields another set of tabs with single letter entries (e.g. “A,” “B,” “C,” etc.) and selecting “A” yields all entries presented with the letter “A.” If a number of entries are provided for the letter A which exceeds the 10-line display of the device, the device will further sort entries into a pre-configured number of further levels of granularity, for example all entries between “A” and “AI,” “AR” and “AT,” etc. The organizer will sort, alphabetize, and granularize each letter of the alphabet depending on the number of contacts beginning with that letter. Selection of different controls occurs through use of one of the six control buttons on the device.
SUMMARY
[0012] An embodiment of the invention, roughly described, comprises a method for converting a list of data, each entry in said list having at least one alpha-numeric character, to a format suitable for display and manipulation in a limited display area. The method comprises: sorting said list based on a first of said alpha-numeric characters in each said entry in said list of data; grouping entries into a plurality of sets, each set comprising entries in said list of data having at least a common first character; generating an abbreviated list of said first characters; and linking each entry in said abbreviated list to the corresponding set of entries having said at least common first character.
[0013] In one aspect, the sorting can comprise alphabetizing the list based on the first and any number of sequential characters in each entry in the list. The list can be divided into sets based upon a predetermined maximum number of allowable entries in the list, and the maximum number defined by the availability of input controllers on a device for which the list is intended. In a further aspect, the abbreviated list entries are mapped to input controllers on the device, and additional abbreviated lists or sets of entries having one or more letters in common are displayed responsive to input from the input controller.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will be described with respect to the particular embodiments thereof. Other objects, features, and advantages of the invention will become apparent with reference to the specification and drawings in which:
[0015] [0015]FIG. 1 is a block diagram of a wireless device coupling to an Internet view of a WAP gateway;
[0016] [0016]FIG. 2 is a block diagram of a network used in accordance with an embodiment of the present invention;
[0017] [0017]FIG. 3 is a graphic illustrating the list reduction and mapping algorithm according to an embodiment of the present invention;
[0018] [0018]FIG. 4 is a graphic illustrating the list reduction and mapping algorithm according to another embodiment of the present invention;
[0019] [0019]FIG. 5 is a flow chart depicting one embodiment of the process flow of the present invention.
DETAILED DESCRIPTION
[0020] An embodiment of the present invention, roughly described, provides a system and method for presenting long lists of items in a format which is suitable for display and interaction on a web browsing device having a small display and limited input/output capability. In particular, embodiments of the present invention are particularly suited to providing long lists of information in a usable format on wireless Internet-enabled cellular telephones.
[0021] Embodiments of the present invention provide particular applicability with respect to alphabetized lists, but it should be recognized that many different types of lists including numerical lists of, for example, a sequence of addresses or alphabetical lists of stock symbols may be processed in accordance with the present invention.
[0022] [0022]FIG. 2 shows a wireless client device 10 which may be a personal digital assistant, wireless cellular phone enabled with a micro browser, or other device capable of accessing a wireless network 15 which is coupled to a WAP gateway 20 . Within the public Internet 25 , a particular website server 50 is coupled to a WAP server 55 to provide content information to the wireless client 10 . In accordance with the invention, the WAP server 55 which is fed content directly from a particular site server 50 , includes a series of processes running on the particular format of the server and implemented by any number of known programming methods to implement an embodiment of the present invention. The WAP server 55 in this embodiment is implemented by a provider or system administrator and implemented for specific content (such as specific web sites) or specific carriers (wireless networks).
[0023] For purposes of example, the method of the invention will be presented with respect to an alphabetical list of the fifty (50) United States. FIG. 3 shows an abbreviated representation of a list of states 100 having a title “List of States” 102 and an alphabetical listing of the 50 U.S. states beginning with Alabama and ending with Wyoming. As noted above, the wireless telephone specification limits the number of bytes of data which can be provided to a wireless phone through the WAP gateway 20 , and further limits the display interactivity to approximately nine items, since only nine items can be mapped to a numeric keyboard with digits 1 through 0.
[0024] In accordance with an embodiment of the invention, the entries in the list are organized alphabetically, with a separate entry being made for each letter which begins a word so that all entries for that letter are thereby correlated to that letter. In one embodiment, this is done by creating a table as shown by example 200 in FIG. 3, wherein each entry for each letter includes all states beginning with that letter: Row “A” includes the entries Alabama, Alaska, Arizona, Row “C” is correlated to the entries California, Colorado, Connecticut, and so on.
[0025] Depending on the maximum number of available entries required on the list (nine in the case of an Internet-enabled cellular phone), the list may be granularized by dividing the total number of table entries by the number of available entries, and an abbreviated list 104 arranged for display as a WAP page on a cellular phone.
[0026] In list 104 , because only eight slots are available (one slot, entry 1 , is used for a command to “show the list”), twenty-six divides by eight three times with a remainder of two, meaning that at most entries (six), three table letters can be assigned, while two of the entries must be assigned four letters. The resulting abbreviated list 104 is shown in FIG. 3. In one embodiment of the invention, the choice has been made to map the alphabetical letters to the commonly-used standard letters to which the numerals on the phone are mapped as shown on a standard telephone keypad. However, it should be recognized that any mapping of entries to key pad controllers may be made. In the particular example shown in FIG. 3, it should be readily recognized that since there are no entries for some letters, such as “B,” “E,” “J,” etc., hence these entries could be removed and the list shortened. For convention, in the example shown, the standardized mapping of letters to the numerals on the keypad on the telephone is utilized.
[0027] As further shown in FIG. 3, if a user selects number 8 on the keypad, the entries associated with the letters “T,” “U,” and “V,” in this case the five entries Tennessee, Texas, Utah, Vermont, and Virginia, will be displayed in a second list 106 . It should be recognized that the second list 106 has only five entries, substantially fewer than that allowed to be displayed on the nine available entries in a standard keypad. Hence, the complete list can be displayed.
[0028] In certain instances, the number of entries mapped to the individual letters in Table 200 will be longer than that available for the nine entries maximum allowed by the standard for a cellular phone. In that case, the method contemplates either providing multiple pages of list entries similar to entry list 106 , each list incorporating nine entries, or performing an additional mapping step to subdivide the entries on the mapped list 104 and hence provide further granularity in the selection process. For example, in FIG. 4, a mapped list 104 may be used to select entry 6 which provides a list 108 of the letters “M,” “N,” and “O.” There are nineteen states which begin with the letters M, N or O. As a result, selection of the number 6 can be allowed to be subdivided to allow the user to select between states beginning with M, N or O as shown in FIG. 4 at 108 , and further to select states beginning with the letter O by depressing a 3 on the keypad, thereby resulting in a display of a list entries for letter O of Ohio, Oklahoma and Oregon.
[0029] In yet another embodiment of the invention, where lists longer than entries such as the U.S. states are utilized, alphabetization and mapping to a table such as table 200 may occur for more than one letter. For example, where a long list of entries such as addresses or cities occurs, entries may be subdivided for the letter “T” for all entries between “T” and “Th,” “Ti” to “Tp” and “Tq” to “Tz.” This multiple mapping granularity can occur for both alpha and numeric lists, and for multiple levels of characters in each entry in the list.
[0030] [0030]FIG. 5 shows a flow chart representing the general method of the present invention. As one who is skilled in the art would appreciate, FIG. 5 illustrates logic boxes for performing specific functions. In alternative embodiments, more or fewer logic boxes may be used. In an embodiment of the present invention, a logic box may represent a software program, a software object, a software function, a software subroutine, a software method, a software instance, a code fragment, a hardware operation or user operation, singly or in combination.
[0031] As shown in FIG. 5, a user 110 utilizing a wireless Internet device or any other Internet-enabled device, will make an HTTP request to a web server 120 which contains any number of documents having a list of entries. On a WAP-enabled server which is provided by an administrator of an embodiment of the present invention, the list document is returned at logic box 122 and examined at logic box 124 to determine whether the input list in the document has a size greater than a predetermined maximum. In the present example where the list is intended to be diverted to user 110 using a wireless Internet-enabled phone, the maximum is nine or multiples of nine such as eighteen, twenty-seven, etc. The maximum can be chosen such that if, for example, the list is eighteen or fewer characters, the list is less than or equal to the allowed maximum and the inquiry to logic box 124 is “no,” such that the list is returned in one or more pages to the user 110 , as illustrated in logic box 138 .
[0032] If the input list is greater than the predetermined maximum, the answer to decision query 124 is “yes,” then the list is sorted by a process running on the WAP server to sort the list by the next unsorted letter at logic box 126 .
[0033] In logic box 126 , if the list is simply the list document 122 which is returned as a result of the HTTP request from user 110 , the next unsorted letter will be the first unsorted letter (n) in each entry in the list. As discussed with respect to FIG. 3, the entries in the list are then mapped, as illustrated in logic box 128 , by the relationship to the next letter into a table such that each entry is associated with its relationship to the next letter (n+1). In other words, all letter entries beginning with A are correlated to the letter A, all entries with B to the letter B, and so on.
[0034] At logic box 130 , the table is examined and the number of table entries is divided by the maximum number of available input options for the device utilized by user 110 . In the case of a WAP-enabled phone, this number is nine, so that the number of entries of the list is divided by nine and the resulting data is used at logic box 132 to map the table entries to data inputs, in this case the keypad, and the transformed list which has been mapped to the keypad is then returned at logic box 134 to user 110 .
[0035] After the user receives the list, the user will generally select one of the mapped items and the method continues at logic box 136 with a determination of whether the mapped list size (i.e. the number of entries associated with the mapped item) is greater than the predetermined maximum utilized throughout the method of the present invention. If the mapped list size is not greater than the predetermined maximum, the method, as illustrated in logic box 138 , will simply return a list of the entries associated with the map entry (for example as shown in FIG. 3, where the number of mapped entries is simply five).
[0036] If the number of entries in the mapped list is greater than the predetermined maximum, a decision in logic box 140 is made to determine whether to sort the next letter in the list. In the alphabetical example of states set forth above, the alphabetization by the second letter is not utilized, but were the example given by a list of U.S. cities having a population greater than 100,000, the answer to decision step 140 would likely be “yes” over several iterations so that the granularity of the mapping can be substantially increased by returning through logic box 126 to map the second, third, fourth, etc., letters in each entry.
[0037] If the answer to decision query 140 is “no” and the next letter in each entry is not to be mapped, a further determination may be made in logic box 142 as to whether or not a sub-map of entries will be required. As shown in FIG. 4, the sub-map may comprise all entries in a given key mapping returned at logic box 134 . In the example shown in FIG. 4, this is letters “M,” “N,” and “O,” which are returned, as shown in logic box 144 , by depressing the keypad number 6. If no sub-map is required at logic box 142 (as in the example in FIG. 4 where the entry 3 is pressed from page 108 ), a list of mapped entries is returned at logic box 146 in one or more pages of all items organized in the table entry for the next letter.
[0038] It should be readily recognized that the methodology set forth in FIG. 5 may be implemented by any number of different processing paradigms. In the present example, a WAP server or other separate process server is utilized to implement the present invention. However, it should be recognized that the process need not be implemented by a WAP server. Moreover, the invention has equal applicability to wireline as well as wireless devices, especially where limited display devices or limited bandwidth networks are used. In addition, the invention finds particular application with respect to devices having limited small display or input capabilities.
[0039] It should be further recognized that the mapping capabilities of the present invention are not limited to keypads. For example, the methodology may be tailored to different types of inputs having more expanded or limited input capabilities, such as pagers having a more limited number of buttons, or full keypad wireless pagers having a greater number of input entries.
[0040] These and other advantages of the present invention will be readily apparent to one of average skill in the art. All such features and advantages of the invention are intended to be within the scope of the invention as illustrated by the written description and the drawings, and defined by the attached claims. | A method for converting a list of data, each entry in said list having at least one alpha-numeric character, to a format suitable for display and manipulation in a limited display area. The method comprises: sorting said list based on a first of said alpha-numeric characters in each said entry in said list of data; grouping entries into a plurality of sets, each set comprising entries in said list of data having at least a common first character; generating an abbreviated list of said first characters; and linking each entry in said abbreviated list to the corresponding set of entries having said at least common first character. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention relies on U.S. Provisional Patent No. 61/307,294, entitled “Simultaneous Image Distribution and Archiving” and filed on Feb. 23, 2010, for priority and is herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to X-ray screening systems. More particularly, the present invention relates to a high speed temporary data storage system that stores high resolution image data and associated detection results.
BACKGROUND OF THE INVENTION
[0003] Increases in terrorist threats has created a need to deploy high speed, high resolution, and more accurate threat screening devices in locations which are most likely targets of such violence, such as ports, airports, train stations, and government buildings. Screening technologies currently employed at most places provide either high speed screening but generate digital radiography images which are not fully three-dimensionally (3D) volumetric, or provide relatively detailed 3D volumetric images using computed tomography (CT) at a slow screening speed.
[0004] Recently developed screening systems such as the real-time tomography (RTT) screening system developed by Rapiscan Systems, Inc. can screen items such as luggage at a very high rate and produce high-resolution 3D volumetric images. FIG. 1 a illustrates the RTT screening system. A piece of luggage 102 is passed through the RTT screening system 100 and a 3D volumetric X-ray image of the luggage 102 is displayed on the monitor 104 . FIG. 1 b illustrates the 3D volumetric image 105 of the piece of luggage 102 screened by the RTT screening system 100 .
[0005] The RTT screening system 100 comprises a stationary gantry CT design that controls a plurality of X-ray emitters. It captures 3D images at several times the speed of legacy CT systems. FIG. 2 is a block diagram illustrating high level data flow in the RTT screening system. The RTT screening system 202 comprises a reconstruction engine 204 which receives sinogram data from RTT hardware 202 , and produces a high resolution 3D reconstructed image. A threat detection engine 206 receives the reconstructed image as an input from the reconstruction engine 204 and processes it by applying one or more automatic threat detection algorithms to generate a decision, e.g. all clear or signal an alarm, on the image. The threat detection engine 206 then passes on the data comprising the image and the result of processing of the image to a storage device 208 , where it is stored temporarily. The same data is retrieved by the 2D and 3D operator workstation(s) 210 , 212 and specifically assigned to alarm resolution stations 214 over a network, such as an Ethernet. Regulatory authorities may require high security regions such as airports to store the image data for a predefined period of time, i.e. up to 48 hours. The data is then written to a disk storage system 216 for long term storage, and passed to various display workstations in real-time. U.S. patent application Ser. Nos. 10/554,656, 10/554,975, 10/554,655, 10/554,570, 12/097,422, 12/142,005, and 12/787,878 disclose various aspects of the RTT system and their specifications are incorporated herein by reference in their entirety.
[0006] The high-speed RTT system can generate a data rate as high as 400 MB/sec. The data is required to be stored for later retrieval, and also accessed by the 2D and 3D workstations 210 , 212 as quickly as possible. Commercially available standard network attached storage (NAS) devices typically store data on an array of hard disk drives. Typically, standard NAS consists of redundant array of inexpensive disks (RAID) to ensure high levels of data integrity. The purpose of the storage array is to store various bag files (.BAG) scanned by the RTT system 202 . The storage array also stores engineering/intermediate data such as information associated with the bag images, system calibration information, system configuration, event logs, among other information.
[0007] Due to file system overhead and read/write seek time of the hard drive sub-system, among other reasons, standard NAS devices cannot effectively simultaneously store the data at high speed and also provide sustained high-speed read access to multiple screener workstations. Typical hard disk arrays have a seek time of about 15 ms. Therefore, when a standard NAS device tries reading and writing at the same time, the hard drive ends up spending most of the time seeking, thus reducing the effective throughput.
[0008] Hence, there is need for a NAS device which provides a high speed temporary storage system that stores high resolution image data and associated detection results. There is also a need for a NAS device that can concurrently or simultaneously store data at high speed and also provide sustained high-speed read access from multiple screener workstations.
SUMMARY OF THE INVENTION
[0009] The present specification discloses a storage system for enabling the substantially concurrent storage and access of data, comprising: a source of data, wherein said data comprises a three dimensional image wherein said three dimensional image has been processed to identify a presence of a threat item; a temporary storage memory for receiving and temporarily storing said data, wherein said temporary storage memory is adapted to support multiple file input/output operations executing substantially concurrently and wherein said data is received from said source of data via one of said multiple file input/output operations executing substantially concurrently; at least two workstations for accessing said data, wherein each of said workstations is configured to access the temporary storage memory through one of said multiple file input/output operations executing substantially concurrently; and a long term storage system for accessing and storing said data, wherein said long term storage system is configured to access the temporary storage memory through one of said multiple file input/output operations executing substantially concurrently.
[0010] Optionally, the temporary storage memory is configured to receive data from said source of data at a data transfer rate equal to or greater than 1.6 gigabytes per second. The temporary storage memory is a RAM buffer having a size of at least 32 gigabytes. Each of said workstations can access said data at a speed of at least 100 megabytes per second.
[0011] Optionally, the temporary storage memory is adapted to receive data from said source of data via a first file input/output operation, transmit data to a first workstation via a second file input/output operation, transmit data to a second workstation via a third file input/output operation, and transmit data to the long term storage via a fourth file input/output operation, wherein each of said first, second, third, and fourth file input/output operations executes concurrently. Each of said file input/output operations is executed via a FTP server thread. The fourth file input/output operation occurs at a rate of at least 200 megabytes per second. The second and third file input/output operations occur at an average rate of at least 70 megabytes per second. Upon receiving a request from a workstation for data that is not present in said temporary storage memory, said temporary storage memory is adapted to retrieve said requested data from the long term storage and transmit the requested data to the workstation.
[0012] Optionally, if said data is not associated with an alarm or a threat, the temporary storage memory transmits the data to long term storage and does not retain said data for access by the workstations. The temporary storage memory receives said data into a TCP offload engine. The TCP offload engine receives data from an Ethernet switch. The Ethernet switch is at least a 10 Gb Ethernet switch. The temporary storage memory transmits data to the workstations via an Ethernet switch. The Ethernet switch is at least a 10 Gb Ethernet switch. Each of said workstations is configured to display 3-D images.
[0013] In another embodiment, the specification discloses a process for high speed storage and access of data wherein said data comprises a plurality of three dimensional images and wherein said three dimensional images have been processed to identify a presence of a threat item system, comprising: receiving said data into a temporary storage memory through a first file input/output operation; transmitting said data to a first workstation through a second file input/output operation; transmitting said data to a second workstation through a third file input/output operation; and writing said data to a long term storage through a fourth file input/output operation, wherein said first, second, third, and fourth file input/output operations execute substantially concurrently.
[0014] Optionally, the temporary storage memory is configured to receive data from a source of said data at a data transfer rate equal to or greater than 1.6 gigabytes per second. The temporary storage memory is a RAM buffer having a size of at least 32 gigabytes. Each of the workstations can access said data at a speed of at least 100 megabytes per second. Each of said file input/output operations is executed via a FTP server thread. The fourth file input/output operation occurs at a rate of at least 200 megabytes per second. The second and third file input/output operations occur at an average rate of at least 70 megabytes per second. Upon receiving a request from a workstation for data that is not present in said temporary storage memory, said temporary storage memory is adapted to retrieve said requested data from the long term storage and transmit the requested data to the workstation. If said data is not associated with an alarm or a threat, the temporary storage memory transmits the data to long term storage and does not retain said data for access by the workstations.
[0015] These, and other embodiments, will be described in greater detail in the remainder of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other features and advantages of the present invention will be appreciated, as they become better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
[0017] FIG. 1 a is a side perspective view of one embodiment of a high speed screening system;
[0018] FIG. 1 b is a 3D volumetric image of a piece of luggage screened by a high speed screening system;
[0019] FIG. 2 is a block diagram illustrating high level data flow in one embodiment of a high speed screening system;
[0020] FIG. 3 is a block diagram illustrating an exemplary data flow architecture in a screening system;
[0021] FIG. 4 is a block diagram of one embodiment of a high-speed screening system employing a hybrid NAS configuration, in accordance with one embodiment of the present invention; and
[0022] FIG. 5 is a block diagram of the hybrid NAS, in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] It is an object of the present invention to provide a high speed temporary storage system that stores high resolution image data and associated detection results.
[0024] The present specification relates to a high speed temporary storage system that stores high resolution image data and associated detection results. The present specification discloses a hybrid NAS which is used in conjunction with high speed X-ray screening systems and makes use of Random Access Memory (RAM) to cache the screening data. The architecture of the hybrid NAS allows the data to be stored in real time as well as be concurrently or simultaneously accessed by monitoring screener workstations, also in real time.
[0025] According to an aspect, the hybrid NAS of the present invention provides random access memory (RAM) to replace the RAID array), thereby eliminating the read/write access time. The hybrid NAS allows random access to the data stored therein, with typical access times of ˜15 μs, which is faster than for hard disk storage devices.
[0026] The present specification discloses multiple embodiments. The following disclosure is provided in order to enable a person having ordinary skill in the art to practice the invention. Language used in this specification should not be interpreted as a general disavowal of any one specific embodiment or used to limit the claims beyond the meaning of the terms used therein. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present specification is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention. The present invention will now be discussed in context of embodiments as illustrated in the accompanying drawings.
[0027] As a threshold matter, it is important to understand the data rates at issue in the present invention. In one embodiment, a screening system needs to be able to store data generated at a rate of at least 125 MB per second, and concurrently or simultaneously provide access to such generated data to at least two separate, networked workstations at a rate of at least 50 MB per second. One of ordinary skill in the art would appreciate that each workstation comprises a computer having at least one processor, memory, and network access. Preferably, the screening system stores data generated at a rate of at least 250 MB per second, and concurrently or simultaneously provide access to such generated data to at least five separate, networked workstations at a rate of at least 65 MB/s. Preferred write data rates can increase to 300 MB/s, 500 MB/s or greater and preferred read data rates can increase to 75 MB/s or greater depending upon the screening system configuration.
[0028] For example, in one embodiment, assuming the image data is produced by a single RTT machine, as described above, and two 3D workstations produce and read the image data simultaneously, three parameters primarily determine the data rate of the RTT system: a) resolution of the reconstruction volume (X, Y and Z), b) belt speed, and c) tunnel size. Shown below are four data rate calculations based upon four different RTT configurations which are as follows:
RTT80 which assumes a 80 cm tunnel size, 250 mm/s belt speed, and 1 mm reconstruction volume resolution; RTT80 which assumes a 80 cm tunnel size, 500 mm/s belt speed, and 1 mm reconstruction volume resolution; RTT110 which assumes a 110 cm tunnel size, 250 mm/s belt speed, and 1 mm reconstruction volume resolution; and RTT110 which assumes a having 110 cm tunnel size, 500 mm/s belt speed, and 1 mm reconstruction volume resolution.
[0000]
TABLE 1
RTT-80 @ 250 mm/sec
Parameters/Assumptions
Avg/Min
Units
Belt Speed
250.000
mm/sec
Size of the bag
750.000
Mm
Max size of the bag
2500.000
Mm
Time to acquire the data for Avg
3.000
Sec
Bag
Time to acquire the data for Max
10.000
Sec
Bag
Minimum Gap between bags
100.000
Mm
Time between bags
0.400
Sec
Shrink Wrap Performance
0.700
Compression performance 3D Vol
0.600
data & mask
Image resolution tunnel width (X)
768.000
Pixel
Image resolution tunnel height (Y)
544.000
Pixel
Size of the 3D projection slice
835584.000
Bytes
Size of the Mask data
417792.000
Bytes
.BAG info (Result + Header)
500000.000
Bytes/Bag
2D Image size
15728640.000
Bytes/Bag
Slice resolution
1.000
Mm
Time to produce 1 mm slice
0.004
Sec
Decompression time on workstation
0.001
s/slice
Number of slices for average bag
750.000
Slices
Number of slices for max bag
2500.000
Slices
Final Data rate
125.826
MB/s
[0000]
TABLE 2
RTT-80 @ 500 mm/sec
Parameters/Assumptions
Avg/Min
Units
Belt Speed
500.000
mm/sec
Size of the bag
750.000
Mm
Max size of the bag
2500.000
Mm
Time to acquire the data for Avg
1.500
Sec
Bag
Time to acquire the data for Max
5.000
Sec
Bag
Minimum Gap between bags
100.000
Mm
Time between bags
0.200
Sec
Shrink Wrap Performance
0.700
Compression performance 3D Vol
0.600
data & mask
Image resolution tunnel width (X)
768.000
Pixel
Image resolution tunnel height (Y)
544.000
Pixel
Size of the 3D projection slice
835584.000
Bytes
Size of the Mask data
417792.000
Bytes
.BAG info (Result + Header)
500000.000
Bytes/Bag
2D Image size
15728640.000
Bytes/Bag
Slice resolution
1.000
Mm
Time to produce 1 mm slice
0.002
Sec
Decompression time on workstation
0.001
s/slice
Number of slices for average bag
750.000
Slices
Number of slices for max bag
2500.000
Slices
Final Data rate
251.651
MB/s
[0000]
TABLE 3
RTT-110 @250 mm/sec
Parameters/Assumptions
Avg/Min
Units
Belt Speed
250.000
mm/sec
Size of the bag
750.000
Mm
Max size of the bag
2500.000
Mm
Time to acquire the data for Avg
3.000
Sec
Bag
Time to acquire the data for Max
10.000
Sec
Bag
Minimum Gap between bags
100.000
Mm
Time between bags
0.400
Sec
Shrink Wrap Performance
0.700
Compression performance 3D Vol
0.600
data & mask
Image resolution tunnel width (X)
1024.000
Pixel
Image resolution tunnel height (Y)
768.000
Pixel
Size of the 3D projection slice
1572864.000
Bytes
Size of the Mask data
786432.000
Bytes
.BAG info (Result + Header)
500000.000
Bytes/Bag
2D Image size
15728640.000
Bytes/Bag
Slice resolution
1.000
Mm
Time to produce 1 mm slice
0.004
Sec
Decompression time on workstation
0.001
s/slice
Number of slices for average bag
750.000
Slices
Number of slices for max bag
2500.000
Slices
Final Data rate
236.568
MB/s
[0000]
TABLE 4
RTT-110 @500 mm/sec
Parameters/Assumptions
Avg/Min
Units
Belt Speed
500.000
mm/sec
Size of the bag
750.000
Mm
Max size of the bag
2500.000
Mm
Time to acquire the data for Avg
1.500
Sec
Bag
Time to acquire the data for Max
5.000
Sec
Bag
Minimum Gap between bags
100.000
Mm
Time between bags
0.200
Sec
Shrink Wrap Performance
0.700
Compression performance 3D Vol
0.600
data & mask
Image resolution tunnel width (X)
1024.000
Pixel
Image resolution tunnel height (Y)
768.000
Pixel
Size of the 3D projection slice
1572864.000
Bytes
Size of the Mask data
786432.000
Bytes
.BAG info (Result + Header)
500000.000
Bytes/Bag
2D Image size
15728640.000
Bytes/Bag
Slice resolution
1.000
Mm
Time to produce 1 mm slice
0.002
Sec
Decompression time on workstation
0.001
s/slice
Number of slices for average bag
750.000
Slices
Number of slices for max bag
2500.000
Slices
Final Data rate
473.136
MB/s
[0033] One of ordinary skill in the art would appreciate how to calculate the final data rate from the parameters shown above. The results provided in Tables 1 through 4 demonstrate that a NAS system being used in conjunction with the RTT system requires data storage, or write speed, in excess of 100 MB/s, preferably in excess of 230 MB/s, and more preferably in excess of 475 MB/s, while the same data is concurrently or simultaneously being accessed by the 2D/3D workstations.
[0034] The hybrid NAS of the present invention provides random access memory (RAM) to replace the RAID array, thereby eliminating the read/write access time. The hybrid NAS allows random access to the data stored therein, with typical access times of ˜15 μs, which is faster than for hard disk storage devices. The high-speed image data stored in the hybrid NAS can then be streamed from the corresponding RAM to a standard NAS system for long-term storage, while the same data can be accessed by the 2D and 3D workstations with minimal delay. Another advantage of the hybrid NAS is that the data can be accessed by multiple clients at the same time. Reading and writing at the same time does not affect the performance of random access memory of the hybrid NAS. The size of the RAM file system of the hybrid NAS can be chosen such that it can store data for a predetermined amount of time at full data rate. In an exemplary embodiment, a hybrid NAS can be configured to store up to 30 minutes of data, at full speed.
[0035] In one embodiment, the high speed temporary storage system provided by the present invention is a hybrid NAS device, which is used in conjunction with a RTT screening system developed by Rapiscan Systems, Inc. as illustrated in FIGS. 1 and 2 . It should be appreciated that the hybrid NAS system can be implemented using standard hardware computing devices and operating system software, such as a 64-bit Linux Operating System.
[0036] FIG. 3 illustrates an exemplary architecture 300 of data flows in an exemplary high speed screening system. It should be appreciated that the devices types, to the extent specific devices are noted, are exemplary and do not limit the nature or scope of the present invention. The system architecture 300 utilizes three dual cell blade systems (DCBS) as the hardware for the threat detection engine 302 . Data generated by the threat detection engine 302 is written to a hybrid NAS 304 via at least a 10 Gb Ethernet switch 306 , or higher, and is simultaneously retrieved by 2D and 3D workstations 308 , 310 over 10 Gb Ethernet switch 312 , or higher. In an embodiment, the system 300 may also comprise an Ethernet controller, separate from or integrated within the servers comprising the NAS 304 . It should be appreciated that the embodiments described above are intended to provide hardware examples and not intended to be limiting. In particular, the system architecture 300 may include any hardware or software that performs the equivalent functionality as the three DCBS systems 302 and Ethernet switches 306 , 312 .
[0037] FIG. 4 illustrates a block diagram of the screening system illustrated in FIG. 3 employing a hybrid NAS configuration. Screening system 402 comprises a reconstruction engine which receives sinogram data, or X-ray sensor data, from its RTT scanning unit, and produces a high resolution 3D reconstructed image. A threat detection engine 404 receives the reconstructed image as an input and processes it by applying one or more detection algorithms to produce a decision as to whether to clear the bag (e.g. provide an okay indication or not activate any alarm) or indicate that the bag should be manually checked or checked again using the same or different screening device (e.g. an alarm). The data generated by the threat detection engine 404 , which comprises three dimensional image data that has been processed to identify a threat item, is transferred to hybrid NAS 406 via one or more switches 408 , such as a 10 GbE Ethernet switch, and a high speed network connection 410 , such as a TCP/IP connection. In one embodiment, data from the threat detection engine 404 may be temporarily stored in a short term memory 412 , such as DDR2, DDR3, SDRAM, or any type of random access memory (RAM), and more preferably, in short term memory that provides transfer data rates greater than 1.6 GB/s, such as, but not limited to, 3.2 GB/s, 6.4 GB/s, or 12.8 GB/s. Short term memory can be a temporary buffer that stores up to the last “n” minutes of data from the system, where “n” may be defined by a user of the system to be 24 hours or down to a few minutes, or any increment therein.
[0038] The hybrid NAS 406 comprises a high speed image processing unit 414 comprising a TCP offload engine (TOE) 416 to rapidly move substantial amounts of data to multiple places, one or more processors 418 , and a RAM drive 420 . The TOE 416 is a technology used in network interface cards to offload processing of the entire TCP/IP stack to the network controller and is known to persons of ordinary skill in the art. It is primarily used with high speed interfaces like 10 GbE, where processing overhead (CPU time) of the network stack becomes significant. The one or more processors 418 process the data from the threat detection engine being stored in the RAM drive 420 . In one embodiment the high speed image processing unit comprises 64 GB to 128 GB of RAM.
[0039] The hybrid NAS 406 further comprises an input/output (I/O) processor 422 , a TOE 424 , and a RAID controller 426 which controls read/write into RAID disk array 428 . In one embodiment, the I/O processor 422 operates at 2.4 GHz or higher and processes the data being written to and being read out of the RAID disk array 428 . The RAID controller 426 controls the read/write operations into the RAID disk array 428 . The data stored using the hybrid NAS 406 is made available to a plurality of external workstations 430 , at a high speed of at least 100 MB/sec and more preferably 125 MB/s, 250 MB/s, 350 MB/s, 400 MB/s, 500 MB/s or greater than 500 MB/s In one embodiment the number of external workstations accessing the data stored in the hybrid NAS 406 ranges from 3 to 15.
[0040] FIG. 5 illustrates a software block diagram of the hybrid NAS 500 , in accordance with one embodiment of the present invention. The figure illustrates a DCBS module 502 (running on a processor) accessing random access memory (RAM) buffer 504 by means of file transfer protocol (FTP) via a FTP server thread 506 using a file input-output (I/O) operation. The RAM buffer 504 is also accessed by 2D and 3D workstations 508 , 510 by means of FTP via FTP server threads 512 and 514 respectively, using file I/O operations. An archiving process 516 accesses the RAM buffer 504 periodically, using file I/O operation and writes data stored on the RAM buffer 504 on a permanent storage device such as a RAID disk array 518 . The archiving process is any programmed process for reading data from memory and writing the data to storage. In one embodiment, the archiving process has continuous access to RAM and the access rate is controlled using an operating system task priority setting.
[0041] In the embodiment illustrated in FIG. 5 , the RAM buffer 504 is accessed by four different threads, i.e. an interface to DCBS 502 for storing real time RTT data comprising image data in the form of files with .BAG extensions, two 2D/3D workstations 508 , 510 for viewing the .BAG images, and a local archiving process 516 running on a local server to perform sequential writes to the local RAID disks 518 , hard disks, or any other form of long term storage. Long term storage may be configurable per a user's requirements. In a typical airport installation, a user may require to store all processed images up to 48 hours. The data are usually stored in RAID, NAS, or SANs. In the embodiment illustrated in FIG. 5 , FTP servers, which are used purely for illustrative purposes, enable multiple workstations to establish concurrent sessions, or instances. In other embodiments, various suitable data transfer protocols which enable the establishment of concurrent instances of data among multiple workstations may be used. It should be appreciated that each workstation comprises a client device, such as a desktop, laptop, mobile device, tablet computer, or other computer with a network connection and interface, a processor, a display, and programmatic applications collectively configured to receive and display three dimensional data.
[0042] If a 3D workstation 508 tries to access a file that is not cached in the RAM buffer 504 , the archiving process 516 reads the required data from the RAID disk array 518 and transmits the data. In an embodiment, under this condition, the performance of the write task slows down, but the hybrid configuration continues cache to the RAM buffer 504 . The frequency of this condition depends on the size of the RAM buffer 504 , which in various embodiments, ranges from 32 GB to 64 GB and caches approximately 50 to 100 .BAG image files.
[0043] In one embodiment, the hybrid NAS 500 illustrated in FIG. 5 is designed to perform intelligent caching. For example, the hybrid NAS 500 can be configured to store only the images associated with an alarm, thereby reducing the amount of memory required. The images which are not associated with an alarm (i.e. cleared) are stored on the RAID disks 518 and removed from the RAM buffer 504 as soon as possible or based on a predefined period of time, such as after “n” minutes have elapsed, or based on a predefined of RAM buffer usage, such as after “X” megabytes of data are stored or after “X %” of the RAM buffer is occupied. One of ordinary skill in the art would appreciate that the “alarm” is generated by the security scanning system, using systems and methods known to persons of ordinary skill in the art. A processor with the security scanning system records to memory an alarm with a specific file, thereby activating the long term storage process, as described above, along with the RAM-based delivery of the file information to workstations. Other screening characteristics could also be used, including bag size, bag contents, passenger destination (using, for example, the system disclosed in U.S. Pat. No. 7,418,077, which is incorporated herein by reference).
[0044] Tables 5A and 5B illustrate the performances of a standard NAS and a hybrid NAS respectively, when operated in conjunction with the RTT screening system under identical conditions.
[0000] TABLE 5A Average Write Speed Average Read Configuration (MB/s) Speed (MB/s) 1 RTT (Write only) 202.2 1 RTT/1 3D Workstation 100.1 68 1 RTT/2 3D Workstation 13 63.7
The results depicted in Table 5A show that the standard NAS was able to sustain approximately 202 MB/s during the write only (1 RTT) cycle. However, the performance of the standard NAS dropped once there is a simultaneous read cycle.
[0000] TABLE 5B Average Write Speed Average Read Speed Configuration (MB/s) (MB/s) 1 RTT (Write only) 236.7 1 RTT/1 3D Workstation 222.3 107.93 1 RTT/2 3D Workstation 226 76.5
The results depicted in Table 5B show the performance of the hybrid NAS. The system as configured was able to sustain approximately 226 MB/sec while allowing two 3D workstations to access the data at the rate of 75 MB/sec. As is apparent by the results illustrated in Tables 5A and Table 5B, the hybrid NAS configuration can achieve relatively high read/write rate required by a high data rate security system.
[0045] The hybrid NAS can be applied to various X-ray screening systems existing in the art including all of the Rapiscan Systems, Inc. security products. The use of the hybrid NAS with the RTT system is only for illustrative purposes and should not be construed as limiting. While the exemplary embodiments of the present invention are described and illustrated herein, it will be appreciated that they are merely illustrative. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from or offending the spirit and scope of the appended claims. | The present specification discloses a storage system for enabling the substantially concurrent storage and access of data that has three dimensional images processed to identify a presence of a threat item. The system includes a source of data, a temporary storage memory for receiving and temporarily storing the data, a long term storage, and multiple workstations adapted to display three dimensional images. The temporary storage memory is adapted to support multiple file input/output operations executing substantially concurrently, including the receiving of data, transmitting of data to workstations, and transmitting of data to long term storage. | 6 |
BACKGROUND OF THE INVENTION
The present invention relates to a method of monitoring the distance between the rolls of roll pairs and the rollers of roller guides of said roll pairs in a rolling line or rolling mill that includes a plurality of mutually sequential roll units, each comprising a roll pair and a roller guide for guiding a bar section, billet or like stock into a respective roll unit, during a rolling operation.
The invention also relates to a device for use when applying the inventive method, and particularly for registering movements in the roller guide that can be later used in the monitoring process.
Rod or shapes are often rolled in a plurality of roll units co-ordinated in a rolling line with the various roll pairs arranged close together, said rolls being arranged in the rolling line in such close relationship as to make visual inspection of the rolling sequence between the roll pairs impossible to carry out. It is also possible that parts of the rolling line are enclosed in a protective casing in order to prevent cooling water from splashing from the rolls into the surroundings, among other things, which also makes inspection of the rolling result between the roll pairs impossible to carry out.
Consequently, the rolling result cannot be assessed until the rod/shape has left the rolling line, and then solely by a visual examination of the rolled product leaving said rolling line. If an adjustment needs to be made, it may be necessary to stop the rolling process so as to enable a manual adjustment to be made to one of the rolls, for instance. Hitherto, no method has been proposed by means of which a maladjusted roll in a roll unit can be determined directly. Instead, the adjustment has been made essentially with a starting point from past experiences of the machine operator and the adjustment is normally made at the place where the adjustment is expected to give the intended result.
SUMMARY OF THE INVENTION
Accordingly, the object of the present invention is to provide a method and means which enable the distance between the rolls of respective roll units to be monitored during a rolling operation and as a consequence thereof also to be adjusted, so as to obtain a rolled product of high and uniform quality.
The aforesaid objects have been achieved with a method and means having the characteristic features set forth in respective associated Claims.
The invention is based on continuously sensing vibrations in the roller guides and analysing their frequency and possibly also their amplitude, so that changes in certain frequencies can be used to give an indication of the state in the roll pair that precedes the roller guide and possibly also in the roll pair that lies downstream of the roller guide in the feed direction of the stock.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to non-limiting embodiments thereof and with reference to the accompanying drawings, in which FIG. 1 illustrates from above a roller guide for a roll pair provided with registering means for application of the inventive method when rolling round rod;
FIG. 2 is an end view of the roller guide shown in FIG. 1;
FIG. 3 is a schematic illustration of part of a roll line having eight roll pairs in which the inventive method can be applied; and
FIG. 4 is an example of a vibration level curve obtained with different adjustments of preceding and following roll pairs in a rolling line.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a typical roll guide for use in rolling mills or lines and having an infeed end 2 and a guide end 3 . The guide end 3 typically includes two grooved and rotatable rollers 4 and 5 which guide the stock 6 therebetween during the rolling process (see FIG. 2 ). The rollers 4 and 5 are carried by arms 7 , 8 fixed to the holder 9 of the roller guide.
Vibration sensors 10 and 11 are each screwed into a respective roller arm 7 , 8 and protected by a protective casing 12 attached to the holder at the guide end 3 of the roller guide. The vibration sensors 10 and 11 are adapted to sense vibrations in the arms 7 and 8 and are connected by signal cables to an electric contact 13 to which a signal cable can be connected for conducting said signals to a process unit 13 a , for instance to a computer equipped with software for automatically analyzing the signals incoming from the sensors 10 and 11 .
A rolling line, or rolling mill, can include a plurality of mutually sequential roll pairs where each alternate roll pair rolls the rod to an oval shape and each other alternate roll pair rolls the rod to a round shape. FIG. 3 is a highly schematic illustration of an example of part of such a rolling line that includes eight roll pairs 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , of which the roll pairs 14 , 16 , 18 and 20 roll the rod to a round shape while the roll pairs 15 , 17 , 19 and 21 roll the rod to an oval shape. The chain line 22 drawn in FIG. 3 indicates the rolling line through which the rod is moved during a rolling operation. A roller guide 1 is provided upstream of each of the roll pairs 14 , 16 , 18 and 20 , i.e. the roll pairs that roll the rod to a round shape. Alternatively, one such roller guide can be provided at each roll pair in the rolling line. All of the roller guides 1 will conveniently be provided with vibration measuring means that enable the inventive method to be applied. The rolls of respective roll pairs can be adjusted relative to each other in a known manner, such as to enable the distance between the rolls of a respective roll pair to be either increased or decreased, because of wear on the rolls on the one hand and also because of differing qualities of the material to be rolled on the other hand.
When the vibration measuring means are used to monitor the state of the rolls, vibrations occurring in the arms 7 and 8 of the roller guides are analysed by frequency analysis. In the case of frequency analysis, vibrations deriving from normal rotation of the rolls, the frequencies of which can be established when the speed at which the stock is advanced and the width and diameter of respective rolls is known, can be sorted out from the analysis and changes in other, selected, frequencies can be used as a measurement of the load on the roll pair concerned. Frequencies deriving from other control points in the rolling line or rolling mill can be analysed and excluded from the analysis during operation of the plant. By studying the frequency changes obtained with a given roller guide as a result of a change in the distance between the rolls of a preceding and following roll pair respectively, it is possible to obtain for each roller guide threshold values corresponding to certain frequencies and to allow these threshold values to provide an indication as to whether or not the rolls function in the manner intended.
Trials have been run in which it was observed that changed results are obtained both in the event of a change in the distance between the rolls of the roll pair that preceded the roller guide and also in the event of a change in the distance between the rolls of the roll pair that followed the roller guide concerned. FIG. 4 is a diagrammatic illustration that shows how the vibration level (in this case the acceleration) changes in a roller guide at the selected frequencies as a result of a change in the distance in the preceding roll pair (F) and also in the following roll pair (E). In the diagram, there is shown at 0 the vibration level in a normal setting of the roll pairs, and with − and + there is shown the vibration level when the distance between the respective pairs of rolls decreases and increases respectively. In addition to acceleration, the vibration measuring process can also be carried out with respect to speed or movement.
After manually testing the rolling mill or rolling line and carrying out a frequency analysis for each of the roller guides and their rollers with a change in the setting of the distance between the roll pairs upstream and downstream of respective roller guides, there can be established threshold levels at which there is delivered a signal indicating that an adjustment needs to be made. Those frequencies that originate from rotation of the rolls and the advancement of the rod can then also be sorted out in the frequency analysis. This can be readily achieved with the aid of computer technology. For instance, the values that caused the signal to be sent can be presented on a computer screen and therewith enable the roll pair requiring adjustment to be manually adjusted.
Data obtained from the aforedescribed frequency analysis can also be presented by continuously presenting the vibration levels of respective sensors on a computer screen in the form of stack diagrams, where different vibration levels are given in different colours so as to enable deviations from a normal state to be easily observed.
When a frequency analysis has been made and the basic setting values have been obtained in accordance with the aforegoing, the processing computer may be coupled to means for setting the respective roll pairs in the rolling line.
The vibration sensors used may conveniently be piezoelectric accelerators that sense all movements, in this case their own movement and also movement of the rollers and the arms, and that deliver a signal whose strength is proportional to the acceleration. The vibration sensor retailed under the designation 353 B67 by Piezotronics Inc., U.S.A., is an example of one type of vibration sensor that can be used to this end.
In addition to being used for the aforesaid purpose, the vibration sensors may also be used in a known manner to detect wear in the roll bearings. This enables faults to be detected and an alarm raised with the same equipment as that used to monitor the distance between the rolls, therewith enabling unplanned interruptions in operation to be prevented when the faults are detected in time. The inventive method can also be applied to detect faults in the setting of the roll pair per se and also in relation to said roll pair, and also enables direct damage to a roll caused by a fault in the rolled material to be detected. Other faults in the roll unit caused by wear on the rolls and the rollers can be detected by monitoring changes in the frequencies generated by said rolls and rollers. | The invention relates to a method of monitoring the distance between the rolls of the roll pairs in a rolling line that includes a plurality of mutually sequential roll units where each unit includes a roll pair and a roller guide for leading a bar section or billet into said unit during a rolling operation. According to the method, the roller guides are provides with vibration measuring means for continuously sensing vibrations in the roller guides. These vibrations are analyzed with respect to frequency, for determining the distance between the rolls of the roll pair that immediately precedes or follows the roller guide. | 1 |
BACKGROUND
[0001] Bend-optimized optical fibers have properties adjusted to the purpose of use, especially an adjusted optimization according to the ability to guide light. This includes fibers which are designed to be highly bend sensitive, e. g. sensor fibers in optical bending sensor devices or optical fibers which are designed to be highly bend insensitive, e. g. optical fibers for the transmission of high data rates with a large bandwidth.
[0002] Bend-optimized optical fibers usually have a structured radial refractive index profile. This profile includes trench structures, regions with graded refractive index, or complex combinations of several trenches of different widths separated by regions with increased refractive index. It is typically very complicated to produce such fibers with the conventional chemical and/or physical deposition methods, i.e. OVD methods, because the deposition parameters are typically very difficult to reproduce during these OVD methods, especially during plasma outside vapor deposition (POVD). In conventional methods, the most complex refractive index region is deposited in the last process step, which can result in the loss of the complete semifinished product. The semifinished product is also known as a preform.
[0003] It remains desirable to have a more reliable method for making bend-optimized optical fibers and improved bend-optimized optical fibers.
SUMMARY
[0004] The present invention is directed to economic and effective methods for the manufacture of a semifinished product for the production of bend-sensitive optical fibers and for the resulting fibers having a predictable refractive index profile that are also efficiently produced.
[0005] The task is solved by a method for the production of a semifinished product for the production of a bend optimized optical fiber, the method including the steps of providing a cladding tube having an inner surface and an outer surface and then forming a protective layer on the cladding tube. The protective layer may be formed on the inner surface of the cladding tube or the outer surface of the cladding tube. A light-guiding layer is then formed on the protective layer. The cladding tube is then collapsed to form the semi-finished optical product. In an alternative embodiment, the cladding tube is collapsed only partially. This method enables complex structures to be formed earlier in the process of forming an optical fiber. Also, the various layers enable more stable fiber to be made from a wider variety of glass types with greater control of the refractive indices.
[0006] In an alternative embodiment, at least one cladding tube with a refractive index below the refractive index of the light guiding core is provided. At least one protective, intermediate and/or barrier layer is applied to the outer and/or inner surface of the at least one cladding tube. Then a light guiding layer are deposited on the inner or outer surface of the at least one cladding tube. The cladding tube produced is at least partly collapsed and/or collapsed onto another substrate to yield a capillary or rod.
[0007] In a further alternative embodiment, assemblies of cladding tubes are collapsed where a rod is used as the substrate. This results in the formation of a semifinished product, wherein the chemical composition of the single cladding tubes may be different.
[0008] In a still further alternative embodiment, the cladding tube is a fluorine doped quartz tube. The fluorine doping results in a reduction of the refractive index of the cladding tube. In an alternative arrangement, the fluorine containing layer is deposited onto an undoped quartz tube with the desired thickness and refractive index and is covered by another layer of undoped quartz as protective layer.
[0009] In various alternative embodiments, the deposition of the light guiding layers is achieved by using chemical vapor deposition (CVD), modified chemical vapor deposition (MCVD) and/or outside vapor deposition (OVD), plasma or flame pyrolysis methods.
[0010] The protective, intermediate and/or barrier layer is preferably formed of a fused silica glass with a higher melting point than the melting point of the cladding tube. This results in an increased stability of the semifinished product and ovalities and excentricities are reduced.
[0011] Furthermore, the protective, intermediate and/or barrier layer has another function in some embodiments. The protective, intermediate and/or barrier layer in one embodiment has a chemical composition which minimizes the differences of chemical and/or physical properties, e.g. thermal expansion coefficient and/or different chemical compositions, during the collapsing of the semifinished product onto a substrate. Therefore these layers can be generated using different transition glasses with different chemical compositions. This reduces or sets stress to the desired level in the resulting optical system.
[0012] After the formation of the light guiding layers, a deposition of at least one further inner and/or outer protective, intermediate and/or barrier layer can be carried out. In that way, the modified cladding tube is prepared on either the inside or outside or both sides in a correct manner.
[0013] In another alternative embodiment, the surrounding and/or inner pressure of the cladding tube is adjusted, i.e. controlled, by a pressure control system. Afterwards in one alternative arrangement, the cladding tube is collapsed to a capillary or a rod. This modified tube may then be collapsed onto another substrate after the deposition of the lightguiding layers. The further substrate can be either a rod or another cladding tube. In another embodiment the collapsing step is at least a partial collapse and it is carried out after the deposition of the light guiding layers to form a capillary or a massive rod. After the partial collapse, a mechanical treatment forming a polygonal rod can be carried out.
[0014] The collapsing steps can be also carried out successively. In one embodiment, a subsequent collapsing step of at least one doped and/or undoped cladding tube or semifinshed product is carried out. When doped cladding tubes are collapsed, the chemical composition of at least one dopant of each substrate can have a constant, linear and/or graded radial profile. By such processing, different refractive index profiles, especially trenches, graded or constant refractive index regions can be applied radially in an outward direction or combined with each other. This processing can be combined with at least one another outside deposition step.
[0015] In further alternative embodiments, the protective, intermediate and/or barrier layers are partially removed. It is preferred to combine glasses with equal or similar chemical composition during the collapsing processes. The protective, intermediate and/or barrier layer can have a chemical composition which reduces the chemical and/or physical differences between the semifinished product and the substrate, particularly differences in thermal expansion coefficient and/or different chemical compositions. With presently disclosed embodiments, layers are successfully produced using at least one transition glass with different chemical composition. This increases the yield of the process step since at least parts of the glasses can be used as transition glasses. In a final processing step at least one of the protective, intermediate and/or barrier layer may be at least partly removed. This induces diffusion processes within the inner structure which result in further modifications of the refractive index profile.
[0016] The process steps mentioned can be accompanied by surface treatment methods. In an intermediate and/or final process step a surface treatment is carried out, the surface treatment being preferably a fire polish and/or plasma polish step.
[0017] The method is to be described more in detail based on the following embodiments. Embodiments are illustrated in the figures wherein same parts are similarly labeled. The present invention together with the above and other advantages may best be understood from the following detailed description of the embodiments of the invention illustrated in the drawings, wherein:
DRAWINGS
[0018] FIG. 1 shows exemplary processing steps in producing a semi-finished product according to principles of the invention;
[0019] FIG. 2 is an illustration of a method of merging several cladding tubes and a massive rod to form a semi-finished product for the production of optical fibers according to one embodiment of the invention;
[0020] FIG. 3 shows an embodiment of a cladding tube according to principles of the invention; and
[0021] FIG. 4 shows an alternative embodiment of a cladding tube according to principles of the invention.
DESCRIPTION
[0022] Methods for the production of a semifinished product for the manufacture of a bend-optimized optical fiber and the resulting optical fibers are disclosed.
[0023] FIG. 1 shows a series of exemplary processing steps for processing a cladding tube 1 in order to make a first semifinished optical product, or “part” according to embodiments of the invention. The cladding tube 1 is, in this example, a quartz tube having a defined thickness. The quartz glass is doped with at least one dopant that changes the refractive index of the glass. The dopant may be, for example, one or more of the following: fluorine, fluorine containing compounds, germanium, phosphorus, aluminum, boron or other halogens and their compounds or other substances. The refractive index of the cladding tube 1 is designed to be lower than the refractive index of the core of the resulting fiber.
[0024] The cladding tube 1 is a substrate for the deposition processes and surface modifications that carried out in the next processing steps. The cladding tube has an inner surface 2 and an outer surface 4 . In a first step, a protective, intermediate or barrier layer 3 is deposited on the inside (i.e., the inner surface) and/or outside (i.e., the outer surface) 2 , 4 of the cladding tube 1 . For convenience, the protective, intermediate or barrier layer will also be referred to as “the protective layer.” The material of the protective layer is selected so that the protective layer is substantially impermeable to the dopants within the cladding tube. The protective layer covers the surface of the cladding tube 1 substantially equally. It tends to prohibit diffusion of the refractive index changing dopants out of the quartz glass matrix of the cladding tube during the next processing steps.
[0025] To carry out the deposition known deposition methods are used. These methods are, for example, wet-chemical dip coating, and deposition processes from vapor or gas phases known as chemical vapor deposition (CVD). During the wet-chemical dip coatings, the cladding tube is either completely dipped in a dipping bath or streamed by a deposition solution on the inside of the cladding tube. To carry out the CVD processes, the cladding tube is locally heated from the outside and streamed by a gas flow on the inside. The gas flow contains the substances for the deposition layer in dispersed form. These substances deposit thermophoretically on the locally heated area of the cladding tube. For the deposition of the complete inner surface of the cladding tube, the position of the local heating is displaced along the tube to yield an equal inside deposition with the protective, intermediate and barrier layer 3 . The protective, intermediate and barrier layer 3 is, for example, made of quartz glass with a melting point above the melting point of the cladding tube. Thereby the protective layer has a stabilizing function in addition to a barrier function.
[0026] Furthermore, the inside and outside deposited protective, intermediate and barrier layer 3 serves as an adhesive layer and/or compensating intermediate layer which minimizes the differences of the expansion coefficients of the material of the cladding tube on the one side and the layers deposited onto the protective layer 3 on its other side. To deposit the protective, intermediate and barrier layer, a CVD method is used.
[0027] The cladding tube 1 modified with the protective layer can be used for further deposition steps on the inside or outside. In the present example, lightguiding layers 6 are deposited on the inside of the cladding tube. The lightguiding layers can be doped with for example, germanium. The cladding tube with the protective layer is the starting structure for the lightguiding structure within the optical fiber. For the inner as well as the outer deposition, similar deposition methods for depositing the lightguiding layers as for the deposition of the protective layer can be used.
[0028] Parallel to the described first semifinished product, other semifinished products are produced, that is, a second and third semifinished product and a core doped with germanium.
[0029] The second semifinished product differs from the first semifinished product in the order of the deposition steps. The second semifinished product contains a fluorine doped cladding tube with a protective intermediate and barrier layer on outer surface of the cladding tube and a germanium doped layer on the inside.
[0030] The third semifinished product contains a fluorine doped cladding tube as well which has a protective layer on its inside only.
[0031] For an outside deposition, it is preferable to use a plasma deposition process. For this, the cladding tube is positioned in the flame region of a moveable plasma burner and rotated. Within the flame of the plasma burner, substances for the deposition of outer lightguiding materials are added. These are deposited on the outside of the cladding tube.
[0032] The inside as well as the outside of the cladding tube may be treated with additional deposition processes. The number of layers that may be deposited on the surfaces of the cladding tube is in theory not limited. Complex structures can be accomplished particularly using deposition processes on the inside of the cladding tube. According to the desired structure of the semifinished product or the optical fiber produced therefrom, further modifications of the semifinished product may be carried out. In particular, another protective, intermediate and barrier layer may be deposited on the outside of the cladding tube. Alternatively, the semi-finished product may be processed to change its shape. This includes flattening, or processing the circular outer shape to a polygonal, hexagonal, octagonal or quadratic shape. Further alternatively, depressions or grooves may be formed along the cladding tube. Such modifications may be carried out by local etching, laser treatment or sputter processes.
[0033] The additional production processes of the cladding tube depend on the location of the cladding tube within the semi-finished product. Using the cladding tube in the core area of the semifinished product, a collapsing step of the cladding tube may be carried out, wherein the cladding tube is collapsed to a massive rod. This collapsing process can be carried out in a controlled way. The pressure difference between the inside and outside of the cladding tube is set up to collapse the cladding tube with a controllable speed and/or to a controllable radius. This pressure difference can be generated either by using an underpressure inside the tube or an overpressure outside the tube.
[0034] In another alternative embodiment, the semifinished product is produced from several single tubes and/or a rod or capillary within a convergent production process. This means that several cladding tubes and the rod with different sizes and depositions are produced at the same time and combined in a final production process, where the several independent production steps of the cladding tubes converge to a final step in which all the tubes and the rod are combined.
[0035] FIG. 2 shows the final combining production process for the manufacture of the semifinished product in this alternative embodiment. In this case, the core rod 8 , a middle cladding tube 9 and an outer cladding tube 10 are used. Each of these cladding tubes 9 , 10 can have the aforementioned inner and/or outer depositions in different shapes and modifications. It is possible as well that at least one of the cladding tubes has a cross section deviating from circular geometry.
[0036] The combination of the cladding tubes 9 , 10 is carried out as a series of collapsing processes. The core rod 8 is used as a starting substrate. In this example, the starting substrate is a prior collapsed cladding tube. In alternative embodiments, the starting substrate is a massive rod.
[0037] The core rod 8 and the middle cladding tube 9 are fitted into each other. Subsequently, the middle cladding tube is collapsed onto the core rod. This collapsing process can be carried out either spontaneously or under controlled conditions with a defined pressure difference. The protective, intermediate and barrier layer on the inside of the middle cladding tube or outside of the core rod are of importance. These induce a tension reduction or tension compensation during the collapsing process.
[0038] The same collapsing process takes place with the middle cladding tube 9 and the outer cladding tube 10 to form the semifinished product. In this case, the middle cladding tube collapsed on the core rod is now the substrate for the collapsing of the outer cladding tube. The resulting semifinished product is a concentrically layered structure with different refractive index areas induced by the base material of the cladding tubes and their inner and outer depositions, which either merge gradually or stepwise to each other and form trench or step structures particularly in the region of the depositions of the cladding tubes, which yield refractive index trench structures after drawing of the optical fiber, which are designed for the bend sensitivity of the optical fiber.
[0039] The semifinished product can be treated by a plasma and/or fire polish and/or a temperature treatment as a whole to yield a semifinished product substantially free of tension with a substantially flawless surface.
[0040] Alternative embodiments for the production of the single parts and the resulting semifinished product are described below.
[0041] FIG. 3 shows a preferred embodiment of a cladding tube containing an inner protective layer 15 , a depressed refractive index trench 16 , an undoped or doped intermediate layer 17 , another depressed refractive index trench 18 and an outer protective layer 19 .
[0042] FIG. 4 describes an advantageous embodiment of a cladding tube containing an inner protective layer 15 , a depressed refractive index trench 18 and an outer protective layer 19 . The outer diameter of this embodiment is, for example, 30 to 40 mm, the inner diameter is, for example, 25 to 35 mm.
[0043] In manufacturing the tube, an auxiliary material is provided in the first step. This is preferably a graphite or SiC-rod, however, any other heat and temperature resistant material can be used. In this example, a graphite rod is used.
[0044] In the next step, the graphite rod is provided with an inner protective layer 15 with a wall thickness of 1-2 mm, preferably 1.5 mm, which is either collapsed onto the graphite rod as a substrate tube or directly deposited. This inner protective layer preferably consists of undoped quartz glass, and it can contain at least one dopant according to the application of the optical fiber. Subsequently, a fluorine doped trench 18 with a wall thickness of 1.5-2.5 mm, preferably 2 mm and a refractive index depression Δn between −0.005 and −0.026 preferably −0.009, is deposited with deposition processes, such as the POVD or MCVD method or the so called smoker.
[0045] Afterwards, an outer protective layer with 0.2-3 mm, preferably 1 mm, is applied either by collapsing a tube with the desired glass composition or by direct deposition with the aforementioned methods.
[0046] After the removal of the auxiliary material—in the present case a graphite rod—a processing and/or cleaning and/or temperature treatment of the inner surface is performed.
[0047] This procedure is followed by an elongating process to make a tube with an outer diameter between 24 and 36 mm, preferably 32 mm. In this tube, the lightguiding layers are deposited using a CVD or PIVD method, such that the refractive index is continuously increased from a certain layer number. The resulting tube is collapsed to a capillary or massive rod.
[0048] The resulting product is either jacketed with a tube with a desired refractive index and wall thickness or directly deposited with further layers of desired refractive index and wall thickness after the outer surface has been polished. This yields the correct core to clad ratio in the resulting optical fiber.
[0049] In another embodiment, the auxiliary material is first provided. The auxiliary material is for example either graphite or SiC, however, any other heat or temperature resistant material can be used. In the present embodiment, a graphite rod with an outer diameter of 43 mm is used.
[0050] In the next step, the graphite rod is deposited with a glass soot layer with desired refractive index. After this step, the deposition of the inner protective layer 15 is performed, the inner protective layer 15 preferably consisting of undoped quartz glass with a thickness of 0.2 to 1.2 mm, and preferably 0.7 mm. Then, a first doped trench 16 with a wall thickness of 0.2-1.3 mm, preferably 0.7 mm, and a refractive index deviation Δn between 0.001 and −0.005, preferably 0.0025, is deposited with deposition methods such as POVD, MCVD or smoker.
[0051] Another intermediate quartz glass layer with a wall thickness of 0.01 and 2.5 mm, preferably 0.7 mm, is deposited using one of the aforementioned methods. The additional intermediate quartz glass layer may be either undoped quartz glass or doped quartz glass with a refractive index difference Δn2=−Δn+/−0,001.
[0052] Subsequent to this intermediate layer 17 , a fluorine doped trench 18 with a wall thickness of 0.3-2.5 mm, preferably 1.0 mm, and a refractive index depression Δn between −0.005 and −0.026, preferably −0.009, is deposited. The other process steps are similar to the first embodiment.
[0053] In another embodiment, an auxiliary material for the tube production is provided, where this auxiliary material is preferably a graphite or SiC-rod. Alternatively, any other heat and temperature resistant material can be used. In the present example, a graphite rod with an outer diameter of 43 mm is used.
[0054] In the next step, the graphite rod is deposited with a glass soot layer having a desired refractive index. This layer is at least partially sintered to a transparent glass layer by the proceeding deposition processes. Afterwards, a fluorine doped trench 18 is built with a wall thickness of 0.4-2.5 mm, preferably 1.5 mm, and a refractive index depression Δn between −0.004 and −0.026, preferably −0.009. The fluorine doped trench is formed with deposition processes, such as the POVD or MCVD or smoker. This tube is covered with an outer protective layer 19 , which consists of undoped quartz glass and has a wall thickness of 0.1 to 3 mm, preferably 0.5 mm.
[0055] After removing the auxiliary material—in this example the graphite rod—a treatment and/or cleaning and/or temperature treatment of the inner surface is performed. One or more stretching processes may then be carried out.
[0056] Subsequently, the desired refractive index structure is applied by inside deposition processes, for example MCVD or plasma inside vapor deposition (PIVD). After completing the inside deposition, a temperature treatment and/or elongating process may be carried out. The resulting product is jacketed after preparing the outer surface with at least one tube having desired refractive index and wall thickness or deposited with additional layers of desired refractive index and wall thickness by means of direct deposition processes. This results in the correct core to clad ratio of the optical fiber. It will be understood by one of skill in the art that the sequence of the single processing steps and deposition parameters, e. g. refractive index, wall thickness, diameter data, layer number and sequence, given in the examples can be adapted according to the application.
[0057] The method was described based on exemplary embodiments. Further embodiments result from the dependent claims and in the course of deviations obvious to the person skilled in the art.
FIGURE LIST
[0000]
1 cladding tube
2 inside
3 protective, intermediate and barrier layer
4 outside
5 lightguiding layers
6 inner lightguiding layer
7 outer lightguiding layers
8 core rod
9 middle cladding tube
10 outer cladding tube
11 inner protective layer
12 first doped trench
13 intermediate layer
14 fluorine doped trench
15 outer protective layer
16 first doped trench
17 intermediate layer
18 fluorine doped trench
19 outer protective layer
[0077] It is to be understood that the above-identified embodiments are simply illustrative of the principles of the invention. Various and other modifications and changes may be made by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof. | Methods for producing a semifinished part for the manufacture of an optical fiber are disclosed. The methods are optimized in terms of bending. The methods include the steps of providing a shell tube with a shell refractive index which is lower in relation to the light-conducting core. Then, at least one protective, intermediate and/or barrier layer is applied to a radially outermost and/or innermost tube surface of the respective shell tube, wherein a build-up of light-conducting layers is realized on the inner side and/or the outer side of the shell tube. Finally, the shell tubes are joined by collapsing so as to form the semifinished part. | 8 |
TECHNICAL FIELD
This invention relates to microwave power switching, and more particularly relates to a multipactor switching device for microwave power in which a radioactive electron source is employed to supply electrons to the multipactor region.
BACKGROUND OF THE INVENTION
In certain types of radar systems a T-R (transmit-receive) switch is employed to block microwave signals above a given power level, while passing signals below the given power level, thereby preventing excessive bursts of power from destroying the receiving equipment. One type of device which has been employed for this purpose is a gas discharge switching tube. In the operation of such tubes a substantial recovery time during which signals cannot be received exists after each discharge; hence the pulse repetition rate of systems incorporating this type of switch is severely limited.
Another type of device which has been employed for microwave power switching utilizes a secondary electron resonance phenomenon termed "multipacting". In multipactor devices a radio frequency electric field is applied to an evacuated chamber including a pair of spaced opposing surfaces each having a secondary electron emission coefficient greater than unity. If the radio frequency electric field is of sufficient amplitude and if the frequency of the electric field is properly related to the surface spacing, electrons will be emitted from one surface and accelerated toward the opposite surface where they will arrive when the electric field reverses its polarity. Secondary electrons will be emitted from the opposite surface, and if the yield of secondary electrons is greater than one, more electrons will be emitted from this surface than impinged upon it. Since the electric field reverses its polarity as the secondary electrons are emitted, these secondary electrons will be accelerated back to the first surface from which they will release new secondary electrons at the same time the electric field reverses its polarity. Thus, the process continues as electrons are accelerated back and forth between the surfaces in synchronism with the alternating electric field. The net result is to establish multipactor action, i.e., electron multiplication in a synchronous alternating electric field between secondary electron emissive surfaces.
The aforedescribed phenomenon may be utilized to provide radio frequency power switching because when the input power to a multipactor switch is greater than the level required to sustain multipactor action, radio frequency power is absorbed by the electrons and is dissipated when these electrons strike the secondary electron emissive surfaces, thereby limiting the power transmitted through the switch to a predetermined lower level.
In previous multipactor switches, a thermionic electron emissive electrode has been employed to provide the multipactor region of the switch with electrons and thereby ensure a rapid commencement of multipactor action in response to an input signal above a given power level. Such an arrangement requires a power supply to provide heating current sufficient to cause thermionic emission of electrons from a cathode or filament, and when the cathode is located externally of the multipactor chamber, a second power supply is required to bias the cathode sufficiently negatively with respect to the multipactor chamber so that the emitted electrons are accelerated into the multipactor region. Further details concerning the aforedescribed multipactor switching devices may be found in U.S. Pat. Nos. 2,674,694 to W. R. Baker, 3,354,349 to K. L. Horn, and 4,199,738 to T. P. Carlisle et al.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a multipactor device which retains the aforementioned rapid turn-on characteristics while eliminating the need for a thermionic electrode and its associated power supplies.
It is a further object of the invention to provide a fast acting, simple, reliable, and durable multipactor switching device of smaller size, reduced weight, and less cost than otherwise comparable devices of the prior art.
It is still another object of the invention to provide a multipactor switch of exceptionally long life.
A multipactor device according to the invention includes a waveguiding structure having a plurality of spaced pairs of opposing electrodes defining respective gaps therebetween wherein multipactor action can occur in response to input microwave power in excess of a predetermined level. A radioactive source of beta particles provides electrons within the waveguiding structure to ensure a rapid commencement of multipactor action in response to an input signal above a given power level.
Additional objects, advantages, and characteristic features of the present invention will become readily apparent from the following detailed description of a preferred embodiment of the invention when considered in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a longitudinal sectional view illustrating a multipactor device in accordance with the present invention;
FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1; and
FIG. 3 is an enlarged sectional view showing the radioactive electron source portion of the device of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 and 2 with greater particularity, a multipactor device 10 according to the invention may be seen to include a metal housing 11, of copper, for example, mounted on a support 12. The interior of the housing 11 defines a waveguiding structure 14 for propagating electromagnetic waves within a predetermined frequency range. Although the wave propagating structure 14 may be of various configurations such as a rectangular waveguide, a ridged waveguide, or an interdigital transmission line, in the illustrated embodiment the waveguide 14 takes the form of a comb-like bandpass filter structure. Thus, the wave propagating structure 14 may comprise a rectangular waveguide in which a plurality of pairs of aligned teeth 16 and 18 project inwardly from opposing lateral waveguide walls.
In order to provide desired impedance matching, as shown in FIG. 1, the waveguide 14 is progressively stepped inwardly in height as a function of distance from its opposite ends such that its height is smallest in the middle region and greatest in its end regions. The cross-sectional area of the teeth 16 and 18 is similarly varied such that the smallest teeth reside in the middle region of the waveguide 14 and the largest teeth are disposed near the respective ends of the waveguide 14. The opposing surfaces of the teeth 16 and 18 may be coated or otherwise provided with a layer of a secondary electron emissive material (i.e., a material having a secondary electron emission coefficient greater than unity) in order to enhance multipactor action.
Each end of the waveguide 14 opens into an impedance-transforming section 20, which may be a standard rectangular X-Band waveguide, for example, and which waveguide section has a greater height and width than the waveguide 14. The interior portion of each waveguide section 20 is provided with an impedance-transforming inwardly projecting step 22. A waveguide adaptor 24, which may be of stainless steel, for example, is attached to the outer end of each waveguide section 20, while a rectangular-to-round waveguide transition member 26, of iron, for example, is attached to the outer side of each adaptor 24. The adaptor 24 facilitates brazing of the transition member 26 to the waveguide section 20 and also affords control of the overall length of the multipactor device 10. The transition member 26 defines a rectangular waveguide portion 28 adjacent to the adaptor 24 and further defines a circular waveguide portion 30 away from the adaptor 24.
Secured to the outer side of each transition member 26 is a circular waveguide section 32. A circular disk 34 of a dielectric material such as alumina is mounted within each waveguide section 32 and sealed to the inner walls thereof. The disk 34 functions as a vacuum window which enables the interior regions of the multipactor device 10 to be maintained at a reduced pressure while enabling microwave energy to readily pass through and thereby enter and leave the interior of the multipactor device. The outer end of each waveguide section 32 is attached to a flanged mounting element 36 to facilitate coupling to an external waveguide or other microwave transmission line (not shown). The various elements 36, 34 32, 26, 24 and 20 may be secured to one another by brazing, for example.
Attached to and communicating with the interior of the waveguide housing 11 adjacent to step 22 at one end of the waveguide 14 (preferably the input end) is a tube 40 which is connected to a vacuum pumping arrangement (not shown). The vacuum pumping arrangement enables the interior regions of the multipactor device 10 to be maintained at a reduced pressure, for example 10 -6 torr, and may also include an ion pump for ionizing gas molecules within the multipactor device 10 and removing resultant ions from the interior of the device.
Attached to the waveguide housing 11 and communicating with the interior thereof adjacent to the step 22 at the other end of the waveguide 14 is an oxygen leak 42. The oxygen leak 42 may include a thin silver tube 44 coaxially mounted on an annular support 46, which may be of nickel-plated stainless steel, for example, within an outer shielding tube 48, of stainless steel, for example. When the tube 44 is heated to a desired temperature (for example, 500° C.), oxygen molecules outside of the tube 44 permiate through the wall of the tube 44 and enter the interior regions of the multipactor device 10. These oxygen molecules serve to oxidize the coating on the teeth 16 and 18 and thereby counteract the reducing action caused by impinging electrons on the secondary electron emissive material.
In accordance with the principles of the present invention, a radioactive source arrangement 50 of beta particles is included in the multipactor device 10 to provide electrons in the interior regions of the wavguide 14 where multipactor action occurs and thereby ensure a rapid commencement of multipactor action in response to an input signal above a given power level. As shown in detail in FIG. 3, the radioactive source 50 is disposed in a transverse bore 52 in the housing 11 extending between the waveguiding surface 14 and the exterior of the multipactor device 10. The bore 52 defines an inwardly projecting annular flange 54 at its end adjacent to the waveguide 14 and a slightly enlarged bore portion 56 away from the waveguide 14. A metal disk 58, which may be of copper, for example, is supported within the bore 52 by the flange 54. The broad surface of the disk 58 facing the waveguide 14 is provided with a coating 60 of radioactive material.
In a preferred embodiment of the invention, tritium (H 3 ) is employed as the radioactive material. This may be achieved by using a coating 60 of titanium tritide or scandium tritide, for example. The coating 60 may be applied to the disk 58 by first vapor depositing titanium or scandium onto the disk 58 to serve as a gettering material and subsequently heating the coated disk in a tritium atmosphere so that the titanium or the scandium on the disk absorbs tritium and forms titanium tritide or scandium tritide, respectively.
Exemplary amounts of radioactive material which may be employed in the radioactive source 50 range from about 0.034 currie to about 0.34 currie (1 currie is a unit of radioactivity equal to 3.7×10 10 radioactive particles per second). As an example solely for illustrative purposes, for a copper disk 58 of a diameter of 0.207 inch and a thickness of 0.01 inch, a titanium tritide coating 60 may be provided in an amount furnishing 1 currie per square inch. This amount of radioactive material provides an electron current (of approximately 6000 eV electrons) on the order of nanoamps. Although this current is smaller than that provided by thermionic electron sources of the prior art, it has been found that the transmitted microwave energy that occurs at the onset of multipactor action decreases only slightly as the electron current is increased substantially from the aforementioned nanoamp range. Thus, electron currents on the order of nanoamps are able to achieve a very rapid initiation of multipactor action without excessive leakage of microwave energy.
The disk 58 is held in place within the bore 52 by means of a tubular sleeve 62, which may be of copper, for example, having an outer diameter substantially the same as the diameter of the bore 52. After the disk 58 has been inserted in the bore 52 in its desired position against the flange 54, the sleeve 62 is placed in the bore 52 against the disk 58 and may be mechanically flared slightly using an appropriate tool so that it snuggly embraces the walls of the bore 52 and firmly holds the disk 58 against the flange 54.
Disposed within and brazed to the enlarged bore portion 56 is pinched-off tube 64, which may also be of copper, for example. Since brazing temperatures would remove radioactive material from the coating 60, the disk 58 and the sleeve 62 are mounted within the bore 52 after brazing the tube 64 to the bore 56. After the disk 60 and the sleeve 62 are inserted into the bore 52 through the then open tube 64 and mounted in their desired positions, the outer end of the tube 64 is pinched-off as shown at 66 to form a hermetic seal. It is further pointed out that any vacuum pumping operation for the multipactor device 10 that occurs at an elevated temperature after the disk 58 has been mounted in the bore 52 will result in the removal of some radioactive material from the coating 60. Therefore, a sufficient amount of radioactive material should initially be provided in the coating 60 to allow for the loss of some material during subsequent elevated temperature processing. In the case of titanium tritide, it has been found that the rate of removal of tritrium molecules increases significantly at temperatures above 200° C.; hence all processing of the device 10 after the disk 58 has been mounted in the bore 52 should be done at temperatures below about 200° C.
It will be apparent that a multipactor device 10 according to the invention is able to provide sufficient electrons within the waveguide 14 to ensure a very rapid commencement of multipactor action in response to an input signal above a given power level, and in a device that is simple, reliable and durable. Moreover, since the need for a thermionic electrode and its associated power supplies is eliminated, a multipactor device according to the invention is smaller, lighter and less costly than otherwise comparable devices of the prior art. In addition, since the life of the electron source 50 is determined by the half-life of the radioactive material employed (tritium has a half-life of 12.2 years), a multipactor switch of exceptionally long life is afforded.
Although the invention has been shown and described with reference to a particular embodiment, nevertheless, various changes and modifications which are obvious to a person skilled in the art to which the invention pertains are deemed to lie within the spirit, scope, and contemplation of the invention. | The disclosed multipactor device has a waveguide bandpass filter structure including a plurality of spaced pairs of opposing electrodes defining respective gaps therebetween in which multipactor action can occur in response to input microwave power in excess of a predetermined level. A radioactive source of beta particles provides electrons within the bandpass filter structure to ensure a very rapid commencement of multipactor action. The radioactive source includes a disk coated with a tritium compound and mounted in a transverse bore adjacent to the bandpass filter structure. | 7 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to AZS (alumina-zirconia-silica) fused cast products having improved characteristics for use in a glass melting furnace. The invention relates more particularly to oxidized AZS products characterized by a homogeneous crystal structure and having elongate dendritic zirconia crystals in the active area thereof. The simultaneous presence of these characteristics provides these products with increased resistance to corrosion by molten glass.
[0003] 2. Description of the Prior Art
[0004] Fused cast products (also referred to as “electro-cast” products) are obtained by melting a mixture of appropriate raw materials in an electric arc furnace or by any other melting technique suited to the products concerned. The molten liquid is then cast in a mold to produce shaped components directly. The product is generally then subjected to a controlled cooling program to cool it to ambient temperature without it breaking. The skilled person refers to this operation as “annealing”.
[0005] AZS products have been known in the art for a number of decades and have supplanted products based only on alumina and silica. U.S. Pat. No. 2,271,366 and U.S. Pat. No. 2,438,552 describe the first improvements to AZS products. FR-A-1 208 577 teaches the production of AZS products under oxidizing conditions. The first generation products tended to release gas bubbles into the molten glass, leading to unacceptable defects in the glass. Changing to oxidizing production conditions improved the strength of the AZS products and the quality of the glass. Oxidized products are generally white-yellow to white-orange in color, whereas reduced products are white to white-gray in color.
[0006] AZS refractory products comprise different phases: alpha-alumina crystals (corundum), zirconia crystals and a vitreous phase. The alpha-alumina and the zirconia are partly combined in eutectic crystals.
[0007] The prior art provides sometimes contradictory teaching as to the nature and the shape of the crystals. U.S. Pat. No. 2,079,101 indicates that it is preferable to have a highly oriented crystal structure in which the crystals are parallel to each other and perpendicular to the faces of the cast block. FR-A-1 153 488 describes AZS products with an interleaved crystal structure which is advantageous in terms of improved corrosion resistance. The above products are first generation products, i.e. reduced products. However, the inventors of FR-A-1 153 488 disclose their invention only in relation to a very particular block shape and their microstructure analyses relate to only a small area of the block. They indicate that it is the chemical composition of the product that produces the required microstructures. In particular, they specify that the crystal structure of their invention is encountered only in a small area of the Al 2 O 3 —ZrO 2 —SiO 2 system in which the silica content is from 16% to 20%. They also indicate that the presence of too high a proportion of sodium oxide has a harmful effect on corrosion resistance and that the Na 2 O/SiO 2 ratio must be limited to 0.14. U.S. Pat. No. 4,791,077 and U.S. Pat. No. 5,171,491 indicate that there is a structural difference between the skin and the core of the components. They also teach that a structure with elongate and interleaved crystals is disadvantageous and propose a solution for obtaining components with a fine and uniform microstructure free from dendritic zirconia crystals.
[0008] The products commercially available at present are oxidized products, such as our ER-1681, ER-1685 and ER-1711 products, which respectively contain 32%, 36% and 40% by weight of zirconia on average.
[0009] The above products contain zirconia which is referred to as “free” or “primary” zirconia (because it is not included in the eutectic crystals). The free zirconia crystals are small and tend to assume a spherical or nodular shape. Eutectic corundum zirconia crystals are also encountered. They have a relatively isotropic shape. Free corundum crystals are often encountered in the products commercially available at present.
[0010] AZS refractories are widely used in glass furnaces, in areas in contact with the molten glass. Some new glass compositions are more corrosive with respect to the materials of which the furnace is constructed. Also, glassmakers are seeking much longer working periods (determined by the service life of the refractories). There is therefore still a need for refractories that are more resistant to corrosion by molten glass. The most sensitive area is at the flotation line. The service life of the furnace is often dependent on the wear of the materials at the flotation line. Also, changes in glassmaking furnace design have increased the loads imposed on the hearth of the furnace. Increased insulation of the hearth to limit the consumption of the furnace, the use of bubblers and the increasing number of electrodes passing through the hearth have led to an increase in the temperature of the hearth where it is in contact with the molten glass, which exacerbates the problems of corrosion. There is therefore a need for products having improved corrosion resistance. It is well known in the art that introducing large quantities of zirconia improves corrosion resistance. However, increasing the zirconia content increases the cost and leads to increased segregation in the product, which can reduce industrial feasibility. Also, the increased zirconia content reduces the thermal conductivity, which is disadvantageous from the point of view of the industrial corrosion rate. The rate of corrosion of a material depends on the glass/refractory interface temperature, which is in turn conditioned by the thermal conductivity of the refractory. The more insulative the refractory product and the higher its interface temperature, the greater its rate of corrosion.
[0011] There is therefore a requirement for an AZS refractory having improved corrosion resistance with no significant increase in zirconia content.
[0012] An object of the invention is to satisfy that requirement.
[0013] In-depth studies have shown that it is possible to obtain an oxidized AZS refractory with increased corrosion resistance with the same chemical composition as typically encountered nowadays, the material being characterized by a novel and improved microstructure in the active area.
SUMMARY OF THE INVENTION
[0014] The invention provides oxidized alumina-zirconia-silica (AZS) refractories containing 40 wt % to 55 wt % Al 2 O 3 , 32 wt % to 45 wt % ZrO 2 , 10 wt % to less than 16 wt % SiO 2 and 1 wt % to 3 wt % of an alkali metal oxide selected from Na 2 O, K 2 O and mixtures thereof, having a microstructure essentially comprising alpha-alumina crystals, free zirconia crystals, eutectic crystals and an intercrystalline vitreous phase, wherein, at least in the active area, more than 20% by number of the free zirconia crystals have a dendritic shape and are interleaved with each other and with eutectic crystals and at least 40% by number of the dendritic free zirconia crystals have a dimension greater than 300 μm.
[0015] A surface area of 64 mm 2 of the active area of the materials preferably contains at least 200 dendritic free zirconia crystals having a dimension greater than 300 μm.
[0016] The materials claimed preferably contain 45 wt % to 50 wt % Al 2 O 3 , 34 wt % to 38 wt % ZrO 2 , 12 wt % to 15 wt % SiO 2 and 1 wt % to 3 wt % of an alkali metal oxide selected from Na 2 O, K 2 O and mixtures thereof.
[0017] For cost reasons, the alkali metal oxide is preferably Na 2 O.
[0018] More than 20% of the dendritic free zirconia crystals are preferably longer than 500 μm.
[0019] A surface area of 64 mm 2 of the active area of the materials preferably contains at least 100 dendritic free zirconia crystals having a dimension greater than 500 μm.
[0020] Surprisingly, it has been shown that it is possible to obtain microstructures offering improved corrosion resistance in a reproducible and homogeneous manner in the active area for a given range of chemical composition and using the oxidizing production method. Trials have been conducted and show also that if the microstructure of the AZS materials contains free zirconia crystals at least 20% of which by number have a dendritic shape and at least 40% of which by number have a dimension greater than 300 μm, corrosion resistance is improved by more than 15% relative to equivalent materials that do not satisfy this condition. Below the above thresholds, and in particular below the minimum dimension of 300 μm, no significant improvement in corrosion resistance is observed, even if the total number of free zirconia crystals is large.
[0021] It has been noted that, in the case of products in accordance with the invention, almost all (at least 80%) of the free zirconia crystals more than 300 μm long are dendritic free zirconia crystals.
[0022] A value of 300 μm has been adopted as a critical limit for the length of the dendritic free zirconia crystals. Analysis of the microstructures of a conventional AZS product used as a reference product showed that the average length of the free zirconia crystals was less than 100 μm and that the longest crystals were 250 μm long. The presence of elongate crystals longer than 300 μm is therefore the sign of a reinforcing. The reinforcing is significant when more than 40% by number of the dendritic free zirconia crystals satisfy this minimum length criterion.
[0023] To understand the role of these crystals in the mechanism of corrosion of AZS products it is necessary to review the various steps of the process of dissolution of the material in contact with molten glass. The phenomenon begins with the penetration of corrosive alkaline elements of the molten glass into the vitreous phase of the material. This is followed by the onset of dissolution of the alumina of the eutectic in the vitreous phase, behind the glass/refractory interface. An interface layer rich in alumina is finally created, which contains the zirconia skeleton of the material. This interface layer is very important because it protects the material. The renewal of this interface by the convection of the molten glass aggravates corrosion of the refractory. It is considered that the presence of zirconia crystals of sufficient size (greater than the dimension of the interface) and the interleaving of those crystals constitutes a reinforcement of the interface layer limiting its renewal. Reducing renewal in this way slows the process of corrosion of AZS refractories. The interleaving of the crystals, which has an important function, is possible only if the crystals concerned are of sufficiently elongate shape. Accordingly, only dendritic free zirconia crystals are taken into account.
[0024] The specified limits for the contents of Al 2 O 3 , ZrO 2 and SiO 2 encompass the compositions of existing conventional commercial materials. The presence of silica is necessary to guarantee industrial feasibility but must be maintained at a level less than 16% because, beyond that value, there is massive penetration in service of corrosive elements of the glass and disintegration of the material caused by strong convection currents encountered in the heaviest wear areas of modern glass-melting furnaces.
[0025] To prevent the formation of mullite and thereby encourage the formation of an intercrystalline vitreous phase rich in silica the total content of sodium oxide and/or potassium oxide must not be less than 1%. The plasticity of this amorphous phase accommodates mechanical stresses associated with cooling of the material and the change in volume associated with the allotropic transformation of the zirconia over a wide range of temperatures. These conditions ensure that the parts are industrially feasible. In contrast, to prevent problems of exudation and reduced corrosion resistance the total content of sodium oxide and/or potassium oxide must not exceed 3%.
[0026] The following description, which refers to the accompanying graph and microphotographs, clearly explains the invention and the advantages of the novel products. The examples are provided in order to illustrate the invention and are not limiting on the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] [0027]FIG. 1 is a diagrammatic view of a block identifying the various faces and dimensions referred to in the following description.
[0028] [0028]FIG. 2 is a graph of the corrosion resistance index as a function of the percentage of zirconia.
[0029] [0029]FIGS. 3 and 4 are microphotographs showing the free zirconia phase of different products.
[0030] [0030]FIG. 5 comprises two microphotographs showing the eutectic phase of two products.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] [0031]FIG. 1 shows a refractory block 1 of height h, width l and thickness e. The block has a cast face 2 , a bottom 3 and a face 4 intended to be in contact with molten glass.
[0032] For purposes of evaluation, several blocks and slabs were made by the fusion method described in French patent No. 1 208 577. A Héroult electric arc melting furnace was used having two electrodes and a crucible approximately 1 m in diameter and able to contain approximately 200 kg of liquid.
[0033] Reference conventional products were made using a voltage of 250 V to 300 V, a current of 1 300 A to 1 400 A and an energy input of 2 000 kW to 2 500 kW per metric ton.
[0034] Products in accordance with the invention were made using a voltage of 250 V to 300 V, a current of 1 500 A to 1 600 A and an energy input in excess of 3 000 kW per metric ton.
[0035] The skilled person is well aware that the above parameters define the production conditions perfectly.
[0036] The raw materials used were more than 98% pure; in particular our CC10 zirconia, alumina, sodium carbonate and zircon sand were used.
[0037] The various tests and measurements described hereinafter were carried out to study the behavior of the various components made.
[0038] A sample was taken to characterize each part. The sample has to be representative of the active area. The expression “active area” refers to the most heavily loaded area, in which the corrosion resistance is to be increased. It can be defined as a function of the use of the part. For a slab (less than 150 mm thick) positioned at the bottom of the tank and in contact with the molten glass, for example, the active area is the whole of the slab, on condition that the height is less than or equal to the width of the slab. For a palisade block the active area corresponds to that part of the block situated at the flotation line. In practice, the active area is regarded as the whole of the volume for which the height is less than 200 mm from the bottom of the block. The flotation line is typically 100 mm from the bottom of the block. In order to be representative, the samples studied (by chemical composition, microstructure and corrosion testing) were therefore taken from the bottom in the case of slabs and 100 mm from the bottom in the case of palisade blocks, i.e. at the level of the flotation line under industrial conditions of use, or from the bottom of the block. The sample was taken perpendicularly to the bottom, which is the face opposite the cast face.
[0039] It is important first of all to define the level of oxidation of the products studied. This can be determined by means of an exudation test. The test is performed on a pellet of the product sampled parallel to the bottom face of the block or slab. To be valid, the test must be carried out on a pellet whose porosity is less than 3%. The pellet is heated to 1 600° C. for 15 hours. Measuring the volume of the pellet before and after the test determines the volume of the vitreous phase exuded by the material. That volume depends on the level of oxidation of the material. Insufficient oxidation leads to the presence of a large quantity of dissolved gas in the vitreous phase, to a reduced viscosity of the vitreous phase and to an under-oxidation of impurities (for example iron), which are then found in the form of metal nodules in the vitreous phase. During heating and/or contact with the glass during the test, ex-solution of the gases dissolved in the vitreous phase and reactions of oxidation of impurities present in the vitreous phase are observed. These phenomena and the reduced viscosity of the vitreous phase encourage expulsion of the vitreous phase. Thus, the level of oxidation of the materials is related to the rate of exudation. If the increase in volume is less than 3% the product is said to be oxidized. All the products referred to herein by way of example (those in accordance with the invention and reference products) are oxidized products.
[0040] The corrosion test used was the static test known as the “small rotary furnace” test described by J. RECASENS, A. SEVIN and M. GARDIOL at the 8th International Glassmaking Congress held in London from Jul. 1 to 6, 1968. Twelve samples were cut in the shape of keystones (height 100 mm, average thickness 45 mm) to construct the wall of a small circular shaft. The resulting shaft contained molten glass and was rotated. The test was conducted with soda-lime glass at 1 550° C. for 3 weeks. The depth of attack at the glass level was measured to assign a corrosion resistance index.
[0041] The microstructures of the AZS products were analyzed and characterized using a JXA-880 R/RL (JEOL) electronic microprobe and an image analysis software. The microprobe produced digital images with different gray levels corresponding to the concentration of the various elements: Al, Zr, Si, etc. The image analysis software deduced from these the various phases present and their respective percentage; the standard deviation of the measurement was less than 0.5%. The free zirconia appeared to be the phase having great influence on the corrosion resistance as a function of the appearance of the crystals that constitute it. There are two very different shapes of free zirconia crystals. With the dendritic shape, the free zirconia crystal appears long and tapered. One dimension of the crystal is then much greater than the other. In particular, the form factor (the ratio L/l between the greatest and smallest dimensions of the crystal) must be greater than 5 for the shape to be dendritic. In contrast, for a nodular or non-dendritic shape, the free zirconia crystal takes the form of nodules, and the various dimensions of the crystal are then relatively similar. It therefore appears that the greatest dimension of the free zirconia crystal is an important characteristic and must be evaluated. To this end, the software recognized free zirconia crystals and determined various parameters of the crystals (L, l, form factor, etc). Dendritic free zirconia crystals are free zirconia crystals having an L/l ratio greater than 5, where L is the length of the free zirconia crystal.
[0042] The main characteristics of the products studied are set out in table 1.
[0043] The chemical analysis as a weight percentage, the complement being alumina, was determined by X-ray fluorescence. The analyses given are those of samples taken as indicated above. The skilled person will be aware that the proportion of zirconia tends to be greater at the bottom of the block because of segregation in the block. The characteristics of the microstructure were evaluated over an area of 64 mm 2 to the rear of the saber cut area (level of the free surface of the glass).
[0044] All zirconia crystals whose surface area is greater than 640 μm 2 were regarded as free zirconia crystals. Zirconia crystals with a surface area less than 640 μm 2 were encountered only at the edges of the eutectic areas. They were very few in number and had no major influence. The characteristics of the microstructures given in table 1 relate only to free zirconia crystals. T is the total number of free zirconia crystals counted over the area
TABLE 1 Microstructure Chemical analysis (%) D300/ D500/ Reference Type ZrO 2 SiO 2 Na 2 O T D D/T D300 D D500 D Ic 282-2* Slab 32.8 14.1 1.27 1690 70 4.1% 0 0.0% 0 0.0% 100 275-2* Block 32.9 15.3 1.28 2194 119 5.4% 4 3.4% 0 0.0% 100 275-5 Block 33.2 15.2 1.26 138 28 20.3% 12 42.9% 4 14.3% 113 282-8 Slab 34.7 13.7 1.52 288 187 64.9% 139 74.3% 88 47.1% 123 289-2* Block 34.9 13.2 1.98 1250 115 9.2% 1 0.9% 0 0.0% 100 275-8 Block 35.9 15.2 2.23 1943 494 25.4% 257 52.0% 144 29.1% 130 282-5 Slab 36.0 14.0 1.56 1058 379 35.8% 244 64.4% 127 33.5% 120 290-8 Block 38.4 12.3 2.10 1568 405 25.8% 268 66.2% 155 38.3% 126 290-2* Block 38.7 13.7 1.96 4495 143 3.2% 34 23.8% 8 5.6% 109 289-11 Block 40.2 11.8 2.14 1435 578 40.3% 319 55.2% 140 24.2% 147 290-5* Block 40.9 12.6 1.94 3381 130 3.8% 51 39.2% 15 11.5% 113 289-10 Block 41.7 11.8 2.08 1850 417 22.5% 289 69.3% 143 34.3% 148 290-11 Block 43.0 12.1 1.96 3079 703 22.8% 338 48.1% 167 23.8% 134 289-9 Block 43.2 10.9 2.19 1427 488 34.2% 333 68.2% 203 41.6% 145 289-5* Block 49.3 9.8 1.90 4351 94 2.2% 7 7.4% 2 2.1% 144
[0045] studied. D is the total number of dendritic free zirconia crystals, for which L/l is therefore greater than 5. D300 is the number of dendritic free zirconia crystals longer than 300 μm. D500 is the number of dendritic free zirconia crystals longer than 500 μm. lc is the corrosion index; the index 100 is that of the reference product, which was our ER-1681 product.
[0046] Eutectic crystals of the materials according to the invention had different morphological characteristics to the reference products. The FIG. 5 microphotographs show that the appearance of eutectic crystals is close to that of free zirconia crystals. One dimension of these crystals is generally very much greater than the other, which gives an elongate appearance.
[0047] The values of the corrosion resistance indices and the FIG. 2 graph show clearly the general tendency of the materials in accordance with the invention of having an improved corrosion resistance. This representation also highlights the logical tendency for corrosion resistance to improve as the zirconia content increases. However, it is seen that, for equivalent zirconia contents, products in accordance with the invention provide an improvement of 15% to 30% in the corrosion resistance index. This also means that products less rich in zirconia, and therefore less costly, can be used to achieve a given level of corrosion resistance.
[0048] From the point of view of the microstructure, it is seen that the total number of free zirconia crystals, partly related to the zirconia content of the product, is not a good indicator for evaluating corrosion resistance. It can be seen that some materials have a very large number of free zirconia crystals without this achieving any improvement in corrosion resistance. Conversely, some materials in accordance with the invention have a relatively small number of free zirconia crystals but nevertheless have a corrosion resistance index significantly higher than the equivalent standard products.
[0049] Without seeking to tie the invention to any particular theory, it is thought that it is above all the shape, and in particular the length, of the crystals that has an important influence on the performance of the materials. If the crystals are small and of nodular shape they do not contribute to reinforcing the microstructure and all that is observed is the effect of the zirconia content, which is known to provide particularly good corrosion resistance. In contrast, when the crystals have an elongate shape and their length becomes sufficiently great, they assume an arrangement in which they are interleaved with each other and with the eutectic crystals, which reinforces the material and improves the resistance to corrosion by molten glass.
[0050] The study showed that in the conventional materials very few crystals were of elongate shape (dendritic free zirconia crystals) and that the average length of the zirconia crystals did not exceed 100 μm to 200 μm. Even if the zirconia content of the product was increased, dendritic free zirconia crystals longer than 300 μm represented only a small proportion of the material. Conversely, in materials in accordance with the invention a sufficient number of elongate crystals was observed that were sufficiently long to be interleaved. FIGS. 3 and 4 and the comparative microphotographs of the products 289-2* and 275-8 or 290-5* and 289-11 and 289-10 or 289-5* and 289-9 clearly show the microstructure differences.
[0051] To observe a significant improvement in corrosion resistance without increasing the zirconia content, it is estimated that the number of dendritic free zirconia crystals must be greater than 20% relative to the total number of free zirconia crystals and that at least 40% of the dendritic free zirconia crystals must have a length greater than 300 μm.
[0052] To obtain materials in accordance with the invention it is necessary to comply with a number of criteria relating to the melting, casting and annealing steps.
[0053] In particular, it is important to maintain a level of oxidation comparable with the reference products. This can be achieved by adopting the so-called “long electric arc” working conditions in which contact between the liquid and the graphite electrodes is minimized and of very short duration.
[0054] It is also important to encourage the zirconia crystal growth phase. To obtain this result it is necessary to operate on several parameters.
[0055] A) First of all, the production cycle must enable total and perfect melting of the raw materials in order to prevent the presence within the liquid of numerous solid particles encouraging the nucleation phase, which would increase the number of zirconia crystals and would therefore limit their growth.
[0056] B) It is also necessary to encourage the zirconia crystal growth phase. To achieve this it is necessary to prevent excessively fast cooling of the liquid on casting. To this end the casting rate is very much greater than those conventionally used.
[0057] C) Finally, it is important to increase the thermal gradients within the block or the slab during the first moments of solidification. This can be achieved by increasing the quenching characteristics of the mold (by using a water-cooled mold for example).
[0058] It is important to note that the conditions for obtaining microcrystalline structures of materials in accordance with the invention are more difficult to obtain under oxidizing production conditions than under reducing conditions.
[0059] As a matter of fact, reduced products are produced either through direct contact of the electrodes with the bath of molten oxides or by creating a very short arc between the electrodes and the bath. These production conditions encourage a homogeneous molten bath (there are strong convection currents in the vicinity of the electrodes) and fewer solid particles are seen. It is also possible for the reduced liquids to be more aggressive in relation to these undissolved particles.
[0060] It has been verified, moreover, that the characteristics of the microstructures of products in accordance with the invention are in fact similar at different points in the active area thereof.
[0061] The study was conducted on a block in accordance with the invention; samples were taken at four points combining two heights, namely 50 mm and 150 mm (i.e. 50 mm to each side of the flotation line) and two thicknesses in the depthwise direction in the block, namely 30 mm and 70 mm. The parameters of the microstructures observed were compared with those of a sample taken at the flotation line (sample A).
[0062] The results are given in table 2:
TABLE 2 Sample A 50.30 50.70 150.30 150.70 T 1395 1305 1497 1067 1234 D 455 438 521 316 381 D/T 32.6% 33.6% 34.8% 29.6% 30.9% D300 280 266 296 200 226 D300/D 61.5% 60.7% 56.8% 63.3% 59.3%
[0063] The above results show that the microstructure criteria for products in accordance with the invention are satisfied throughout the active area of the parts studied.
[0064] Materials in accordance with the invention can optionally contain other oxides in addition to the main oxides mentioned above.
[0065] Accordingly, under production conditions as described above for products in accordance with the invention, a series of blocks was made each containing one of the following optional oxides: B 2 O 3 (0.4% to 2.0%), BaO (0.4% to 3.8%), Cr 2 O 3 (0.4% to 5.0%), Li 2 O (0.4% to 1.3%) and MgO (0.4% to 1.0%), all the above proportions being percentages by weight relative to the total composition. Mixtures of optional oxides can also be used, provided that the total amount of optional oxides does not exceed 5% by weight.
[0066] Qualitative observation of the microstructure of the products using an optical microscope showed that the optional oxides did not prevent the obtaining of a microstructure containing a sufficient number of dendritic zirconia crystals longer than 300 μm.
[0067] Table 3 below sets out examples of chemical analyses of materials in accordance with the invention containing K 2 O or one of the optional oxides mentioned above. The proportion of Al 2 O 3 (not indicated) corresponded to the difference between 100% and the total for the constituents indicated.
TABLE 3 Refer- ence ZrO 2 SiO 2 Na 2 O K 2 O B 2 O 3 BaO Cr 2 O 3 Li 2 O MgO 6525-5 35.1 13.5 1.33 0.47 6428-1 34.1 15.0 0.71 1.60 6428-2 34.2 14.8 0.60 1.91 6428-4 34.3 14.7 0.49 2.22 6422-2 34.3 14.7 1.13 0.54 6371-6 37.0 13.9 1.08 1.80 6417-2 33.6 14.3 1.07 1.50 6632-1 35.4 13.0 1.38 1.18 6417-1 34.3 14.4 1.06 2.20 6632-4 34.8 12.8 1.22 2.83 6277-1 33.1 15.1 1.38 1.35 6651-2 33.6 13.9 1.51 2.58 6296-4 34.4 15.6 1.56 5 6444-1 35.1 15.1 1.23 0.81 6444-4 34.5 15.2 1.23 0.97 6445-1 34.6 15.2 1.23 1.28 6458-3 33.2 14.5 1.22 0.42 6458-6 33.4 14.3 1.23 0.58 7417-1 34.7 14.0 1.11 0.52 7277-1 35.2 14.5 1.45 0.61 7444-1 35.7 15.0 1.32 0.63 | Oxidized alumina-zirconia-silica (AZS) refractories containing 40 wt % to 55 wt % Al 2 O 3 , 32 wt % to 45 wt % ZrO 2 , 10 wt % to less than 16 wt % SiO 2 and 1 wt % to 3 wt % of an alkali metal oxide selected from Na 2 O, K 2 O and mixtures thereof have a microstructure essentially comprising alpha-alumina crystals, free zirconia crystals, eutectic crystals and an intercrystalline vitreous phase. At least in an active area, more than 20% by number of the free zirconia crystals have a dendritic shape and are interleaved with each other and with eutectic crystals and at least 40% by number of the dendritic free zirconia crystals have a dimension greater than 300 μm. | 2 |
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of my prior application, Ser. No. 07/698,951, filed May 13, 1991, presently in the Issue Branch of the United States Patent and Trademark Office and now U.S. Pat. No. 5,121,796, which issued on Jun. 16, 1992.
RIGHTS TO INVENTIONS UNDER FEDERAL RESEARCH
There was no federally sponsored research and development concerning this invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to diesel engines and oil rigs for producing oil wells. Particularly, this invention relates to a remote control for a diesel engine used to transfer sludge and other waste material which flow from an oil casing during maintenance thereof. Also more particularly, this invention relates to preventing pollution of the environment.
2. Description of the Related Art
Often oil is produced from deep within the earth by pumps which pump the oil to the surface of the earth. The pumps, being mechanical devices, often need repair and maintenance. This is normally done with a work-over rig which normally will have a derrick to pull sucker rod and tubing from the casing within an oil well. Often, as the sucker rod or the tubing and pump are pulled from the well, oil will be forced out of the well. Particularly if the tubing is pulled the tubing will often be full of crude oil and as each joint of tubing is disconnected, crude oil within the tubing will run out of the tubing. If the oil spills upon the earth it will often be washed by rain water into streams or percolate through the earth into underground aquifers. In either event, pollution of the water in the stream or in the aquifer will occur.
In addition, the crude oil will often have with it many other substances many of which are more harmful than the petroleum products themselves. In addition, many wells produce noxious if not toxic gases. On some wells it is necessary that the workers wear protective breathing equipment.
Many people have previously attempted to control leaks and spills around oil wells. For example, the DEWEY U.S. Pat. No. 113,638 issued in 1871, discloses a bag or rubber sock which may be connected around the top of the tubing on an oil well to prevent leakage from an operating oil well from running upon the ground. DYER U.S. Pat. Nos. 3,353,606, in 1967 and JOHNSTON 3,270,810 in 1966, show similar flexible containers to prevent the loss of oil. Likewise, BEARD U.S. Pat. No. 1,418,612 in 1922, and RETHERFORD U.S. Pat. No. 4,665,976 in 1987, show rigid containers surrounding the tops of operating oil wells to prevent loss.
EVANS, U.S. Pat. No. 4,949,784 issued in 1990, discloses a basin or vat attached around the top of an operating oil well to catch any leakage therein. In this instance the leakage is drained by gravity into an open pit dug in the ground which is lined with a material such as Fiberglass to prevent the crude within the sump from seeping into the earth. It is suggested that the sump be emptied by a hose to suck the material from the bottom of the sump. Petroleum products that had leaked from the well would pass through the surface pump.
SCHUYLER, U.S. Pat. No. 1,507,628, in 1924 devised a vat to attach around the casing. The oil was sucked from the bottom of the vat using an aspirating device which produced a suction by the flow of oil from a pumping oil well. SCHUYLER would operate only when there was a flow of fluid from the oil well.
My prior patent application identified above, described how a vat could be placed around the casing; the vat included a lip to prevent liquid from sloshing out over the edges of the vat. Also the vat was emptied by sucking the fluids into a vacuum tank which pulled the fluids by pulling gas off the top of the vacuum tank. However, in some wells that produced an excess of liquids, there was a problem of the vacuum tank being filled up and the work delayed while the tank was being emptied. Also, the prior application did not disclose a vacuum line directed directly to the casing of the well.
Also, the prior application disclosed only an electric motor to power a vacuum pump.
SUMMARY OF THE INVENTION
(1) Progressive Contribution to the Art
This application discloses a means for emptying the liquid from the vacuum tank as work is progressing so that a reduced pressure or vacuum is maintained upon the vacuum tank. Thus the work upon the well is not interrupted.
In addition, remote controls have been developed for diesel engines so that a diesel engine can be used to power the equipment upon the remotely located vacuum tank without a person being positioned at the vacuum tank or having to travel to and from the vacuum tank. Basic procedures around an oil well require that the auxiliary equipment be placed over 100 feet from the well head for safety purposes.
In addition, the equipment on the vacuum tank has been rearranged and redesigned so that the diesel engine operates a hydraulic pump which operates a vacuum pump to remove gas or air from the tank so that an initial vacuum is created. After the initial vacuum is created the hydraulic system can be switched to drive a liquid pump which pumps liquid from the vacuum tank into an open holding tank. The liquid in the open holding tank can remain in the tank for an indefinite period of time until the tank may be emptied into a tank truck. It will be understood that the trailer, which normally carries the vacuum tank, is of a design that is not adapted to be moved when fully filled with liquids. I.e., the weight capacity of the tires and axles are such that they will readily support the vacuum tank full of liquid in a stationary position but not to transport the liquid to a remote point for disposal.
The hydraulic motor operating the liquid pump as well as the liquid pump itself may readily be reversed so that if there is a certain amount of sludge that does not readily flow from the tank, other liquids can be introduced into the vacuum tank for cleaning out the sludge or the like in a washing operation.
Also, when the line is to be disconnected from the holding tank, the pump may be reversed so that the line can be emptied back into the vacuum tank to prevent the polluted liquid within the line from flowing upon the ground.
Also, a connection is provided so that the suction line from the well casing to the vacuum tank can be connected directly into the well casing instead of into the vat so that noxious or toxic gases may be sucked into the vacuum tank. It is understood, of course, that at the vacuum tank the gases are released to the atmosphere but at a sufficient distance to pose no particular hazard to the workmen at the well head.
The difficulty in providing a remote control from the diesel is that the starter as a unit upon a diesel engine needs to be heavy duty equipment and therefore the control circuit or the activating circuit to the starter itself requires a medium amount of current. There is over 200 feet of wire, including over 100 feet to the remote control and over 100 feet back. With the normal current required to operate the controls for the starter, there is sufficient resistance in the normal 14 gauge wire to result in a voltage drop, making the voltage insufficient for reliable operation. Therefore, a light starter relay was placed at the engine where the length of the wiring is a matter of inches rather than feet and the voltage drop is controllable.
In addition to this, the running of the small diesel engine at the vacuum tank cannot be heard above the normal noise of diesel engines which operate the rig machinery. Thus the workmen cannot tell whether the small diesel is running or not. This made it necessary to put an indicator light on the remote control to indicate that it was running. The voltage for the indicator light was conveniently taken from the run circuit. It is to be understood that diesel motors often can carry safety switches which will kill the operation of the engine upon over-heating or loss of oil pressure. Therefore, if the engine stops and there is loss of oil pressure, this switch will open and turn off the indicator light so that the workmen at the rig know of this problem. Also it is desirable at starting that they know that they have actually started the engine which will occur when the oil pressure reaches sufficient pressure to close the safety switch and turn on the indicator light.
(2) Objects Of this Invention
An object of this invention is to prevent oil spills at the well head from polluting the environment.
Another object is to remotely start and operate a small diesel engine.
Further objects are to achieve the above with devices that are sturdy, compact, durable, lightweight, simple, safe, efficient, versatile, ecologically compatible, energy conserving, and reliable, yet inexpensive and easy to manufacture, connect, operate, and maintain.
Other objects are to achieve the above with a method that is rapid, versatile, ecologically compatible, energy conserving, efficient, and inexpensive, and does not require highly skilled people to connect, operate, and maintain.
The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawings, the different views of which are not necessarily scale drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a work-over rig at a well head with the vacuum tank, holding tank, and truck tank connected thereto.
FIG. 2 is a top plan view of the vat according to this invention with portions of the platform of the rig shown mostly broken away.
FIG. 3 is a schematic representation of the well head with a vat according to this invention attached thereto.
FIG. 4 is a top plan view of the spool with the disk attached thereto.
FIG. 5 is a sectional elevational view taken substantially on 5--5 of FIG. 4 showing a portion of the vat attached to the spool.
FIG. 6 is a perspective view of the vacuum tank mounted on a trailer with the associated equipment.
FIG. 7 is a front elevational view of the vacuum tank on the trailer, with part of the tongue broken away.
FIG. 8 is a rear perspective view of the vacuum tank on a trailer.
FIG. 9 is a front elevational view of the remote control unit.
FIG. 10 is a front elevational view of the panel which is mounted on the engine.
FIG. 11 is a representation of the diesel engine somewhat schematic showing some of the parts and solenoids used in connection with this invention.
FIG. 12 is a schematic representation of the wiring of the remote control unit and the electrical engine elements pertinent to this invention.
As an aid to correlating the terms of the claims to the exemplary drawings, the following catalog of elements and steps is provided:
10 oil well
12 casing
14 well head
16 rig
18 platform
20 blow out preventor
22 nipple
24 valve
26 spool
28 spool top
30 spool bottom
31 disk
32 drain hole
34 nipple
36 hose
38 bolt holes
40 vat
42 circular hole
44 gasket
46 internal flange
48 basin
50 inlet nipple
52 conduit
53 wheels
54 vacuum tank
55 hitch
56 trailer
58 tank inlet nipple
60 man hole/dome
62 vacuum pump
64 liquid separator
66 vacuum air hose
68 power means
70 clean out opening
72 clean out cover
74 diesel engine
76 hydraulic pump
78 hydraulic reservoir
80 filters
82 valve manifold
84 hydraulic motor
86 liquid pump
88 hydraulic motor
90 reverse valve
92 discharge hose
94 holding tank
96 truck tank
98 truck
100 key switch
102 run switch
104 start switch
106 run solenoid
108 high-amperage connection
110 low amperage connection
112 battery
114 activating circuit
116 starter
118 heavy electrical cable
120 hour meter
122 safety switch
124 speed solenoid
126 connecting rod
128 governor arm
130 remote control unit
132 engine connecting plate
134 electrical cable
136 speed switch
138 remote run switch
140 remote start switch
142 start relay
144 relay switch
146 relay coil
148 indicator light
152 plug
154 board
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawing there may be seen, particularly in FIG. 1, the representation of an oil well 10 having casing 12. The casing extends from casing top or well head 14 above the surface of the ground to a bottom far below the surface of the ground.
Also seen is rig 16 which has platform 18 which is around the casing top 14. The platform 18 is conveniently made of grating.
The casing top, or well head, will include blow out preventor 20. The casing 12 will have nipple 22 in the casing immediately below the blow out preventor 20. Valve 24 will normally be in the off position. As shown in my prior application, spool 26 is attached to the top of casing 12. The spool between spool top 28 and spool bottom 30 has disk 31 welded thereto. The casing 22 and the axis of the spool 26 will be vertical and the disk 31 will be at right angles to this axis which is to say the disk will be horizontal. The casing 12 will have a certain diameter, for example 5 inches plus or minus a half inch. The disk typically will have a diameter which is about 8 or 10 times the diameter of the casing. The disk will have drain hole 32 in it. The drain hole will have nipple 34 attached below it. The nipple will be a means for connecting a 2" hose 36 thereto.
Around the perimeter of the disk 31 there will be a series of bolt holes 38.
Vat 40 is preferably of square outer shape for convenience in manufacture. The vat will have a width and a length about 20 times the diameter of the casing. From the top of the vat 40 to the bottom of the vat will be about twice the casing diameter. The vat will have circular hole 42 in its bottom. A series of bolt holes around the circular hole 42 will mate with the bolt holes 38 in the disk 31.
The vat 40 will be bolted to the top of the disk 31. Gasket 44 between the disk and the vat forms a liquid-proof seal between the two. Basin 48 is formed by the spool 26, the disk 31, and the vat 40.
Internal flange 46 is an inch or two below the top of the vat 40. The purpose of the internal flange is to prevent liquids which might flow into the basin 48 from splashing or sloshing out. Internal flange will extend into the vat from the sides thereof a distance about equal to the diameter of the casing.
Inlet nipple 50 is attached at the top of the vat 40 above the internal flange 46. Conduit 52 in the form of a hose is connected from the valve 24 to the inlet nipple 50. Therefore in the event some pressure develops within the casing 12, the blow out preventor 20 may be closed and the valve 24 opened. This will bleed off the pressure from the casing. In the event there are some liquids, either natural or condensate flowing up from the casing, the liquid will drain into the basin 48 as will any spills coming out of the casing.
Hose 36 extends to closed container or vacuum tank 54 which is mounted upon trailer 56. Conveniently the trailer will be located 100 feet or more from the casing so that the trailer is clear of the casing and the rig 16 and the workmen working around it. Also, explosion safety measures require auxiliary equipment to be at least 100 fee from the casing. The trailer 56 will be mounted upon ground engaging wheels 53. Also, as is common with trailers, the trailer will have a hitch 55 which forms a means for moving the trailer 56 and the vacuum tank 54 mounted thereon.
The hose 36 will be connected into tank inlet nipple 58 upon the vacuum tank 54 near the top thereof. The vacuum tank will include man hole with cover or dome 60 on the top thereof.
Vacuum pump 62 is mounted upon the trailer 56. The inlet of the vacuum pump is connected to a liquid separator 64 which is also on the trailer. The inlet of the liquid separator is connected by a suitable vacuum air hose 66 to the man hole/dome 60. Power means 68 is drivingly attached to the vacuum pump 62.
Therefore in operation, if liquid or liquid mixed with sand, mud, paraffin, or other material is found within the oil well 20 or pulled up through the casing 12, spills over the casing top 14, it will flow over into the basin 48. As stated before, the internal flange 46 will prevent the liquid from splashing out of the basin. If the basin begins to fill, the foreman, by operation of suitable controls which will be more fully explained later, can start the power means 68 which will pull a vacuum through the liquid separator upon the vacuum tank 54. Having a pressure less than atmospheric pressure upon the vacuum tank will be transferred to the basin by the hose 36 and the atmospheric pressure upon the liquid in the basin 48 will force the liquid slop in the basin through the hose into the vacuum tank 54. Thus the tank 54 functions as a suction source connected to the drain hole of the basin 48. In the event that some of the liquid in the vacuum tank should reach the outlet in the dome 60, the liquid will be caught in the separator tank 64. If liquids continue to flow into the basin, obviously the motor would remain running to pull the liquid out of the basin substantially simultaneously with pulling the tubing from the casing. However, if there is no continuing flow from the basin, the motor might be turned off by the foreman at the rig 16.
Large clean out opening 70 with a clean out cover 72 is on the vacuum tank.
The invention as described to this point is as described in my prior invention disclosure and as described above, has not been substantially changed.
According to this invention, one change is that the hose 36 may be removed from the nipple 34 and attached to the valve 24. This has certain advantages inasmuch as if there is noxious or toxic gas in the casing, such as hydrogen sulfide, that it may be pulled from the casing for the safety of the workmen.
It will be understood that even if the hose is left connected to the nipple 34, if the vacuum pump is running with an empty vat, the vacuum will produce a reasonable suction to pull off considerable fumes in that vicinity. It will be noted that hydrogen sulfide is slightly heavier than ambient atmosphere, and therefore would not necessarily tend to rise.
According to this invention the preferable form of the power means is small diesel engine 74 having a horse power rating of between about 20 and 25 hp running at speeds from 2000 rpm to 3000 rpm. Diesel engines of this size are readily available commercially. Diesel engine 74 is connected directly to hydraulic pump 76. The hydraulic pump will have the standard elements connected in the standard manner, such as hydraulic reservoir 78 and filters 80 for proper operation. There will also, of course, be by-pass valves to limit the out-put pressure. By valve manifold 82 the hydraulic fluid may be directed to hydraulic motor 84 drivingly connected to the vacuum pump 62 so that the vacuum pump is drivingly connected to the power means 68 as previously described.
As an alternate mode of operation liquid pump 86 is mounted upon the trailer 56. Liquid pump 86 is driven by hydraulic motor 88 which is connected by hoses (not shown) into the valve manifold. Also, the hydraulic motor 88 has reverse valve 90 at the manifold 82 so that it may be driven in the forward direction to pull fluids from the vacuum tank 54. The outlet of the liquid pump 86 is connected to discharge hose 92. The discharge hose leads to open holding tank 94.
As an alternate method of operation once a vacuum has been produced upon the vacuum tank 54 and there is a reasonable supply of liquid within the tank 54, then by removing liquid from the tank 54 by the liquid pump 86 will maintain the vacuum upon the vacuum tank so that liquid is still sucked from the vat 40 into the vacuum tank as before. If the fluid as sucked from the vat 40 produces gas, it may be occasionally necessary to draw gas or air from the vacuum tank by the vacuum pump 62. Oil field workers of ordinary skill will understand this process.
It will be understood that the holding tank will periodically be emptied by pumping the contents of the holding tank into truck tank 96. The truck tank would be a tank mounted upon an over-the-highway truck 98. Such truck tanks and the like are commercially available in the oil-field areas to haul salt water and other pollutants.
Therefore basically the operation of the unit would be that the pollutants or slop that spill into the basin 48 are sucked into the vacuum tank 54 and that the vacuum would be maintained on the vacuum tank by pumping liquids within the vacuum tank 54 into the holding tank 94. Then as the holding tank became filled a truck 98 would be called to empty the contents of the holding tank 94 into the truck tank 96 where it would be hauled to a place of disposal.
The liquid pump 86 is reversible so that the discharge hose 92 can be drained back into the vacuum tank so that there will be no possibility of substantial liquid spillage when operations are discontinued.
If sludge builds up within the vacuum tank liquids can be introduced into the vacuum tank by the liquid pump to flush out sludge. If this is unsuccessful, of course, the clean out opening 70 may be opened by removing the clean out cover 72 and the sludge and the like manually removed at a place suitable for its disposal.
Dependable, inexpensive remote controls for diesel engines were not readily commercially available. Therefore a new remote control was designed and constructed.
Normally diesel engines have key switch 100 to start the engine.(FIG. 12) This is normally a three-position switch having an off position, a run position, and a spring-loaded start position. By spring loaded it is meant that if there is no manual pressure upon the key that the key will return from the start position to the run position. In the run position the run switch 102 will be closed. Spring loaded start switch is designated as 104.
The standard diesel engine will have a run solenoid which is connected to the "rack" of the fuel injection system so that if the run solenoid is not engaged the engine will not run. The run solenoid 106 has two connections. One is high amperage connection 108 which is used to activate the electro magnet therein. Once the electro magnet is activated to pull the rack into run position it is normally maintained in the run position by low amperage connection 110. Therefore the start switch 104 is used to connect the B+ voltage from battery 112 to activating circuit 114 of starter 116. The starter has heavy electrical cable 118. The activating circuit 114 is connected to the high amperage connection 108 upon the run solenoid 106 so that as the engine is started that the run solenoid is also activated. The low amperage connection to the run solenoid is connected to the B+ connection of the battery 112 by the run switch 102. Hour meters 120 are also connected to the run switch so that any time the run switch is on it is registered as running time upon the hour meter 120.
To prevent damage to the diesel engine 74 there will normally be safety switch 122. The safety switch will be closed if there is sufficient oil pressure for the engine and if the temperature of the engine is below maximum operating limits. Other safety parameters may be connected into the safety switch but at least the oil pressure is one of them. If the oil pressure is below acceptable limits or if the temperature is higher than acceptable limits the safety switch will open. Such switches are standard equipment. The safety switch is connected between the run switch 102 and the run solenoid 106. Therefore, if the safety switch is open there is no current to maintain the run solenoid and it will return to its normal position which disconnects the rack so that the fuel injectors of the engine are inoperable and the engine will not run in such a condition.
Diesel engines are normally run by a governor and these governors are set to adjust the fuel injectors so that whatever speed is set on the governor the engine will by the fuel adjustment will be adjusted to run at that speed.
The description of the diesel engine and its starting and controls as described to this point is normally standard or available on small diesel engines.
To make the diesel engine particularly adaptable for the operation from a control position over a 100 feet from the diesel engine as economically and dependable as possible, speed solenoid 124 is connected to the governor. This solenoid has connecting rod 126 connected to governor arm 128. The effective length of the connecting rod 126 is adjusted by stop nuts upon the connecting rod so that the fast or operating position can be adjusted as well as the slow or idle position. It is desirable to normally adjust these so the idle position is about 1000 rpm and the operating position is about 2000 rpm. The speed solenoid 124 is connected so that without voltage applied to it, it is in the idle position.
Remote control unit 130 (FIG. 9) is connected to engine connection plate 132 (FIG. 10) by about 125 feet of electrical cable 134 which has at least six wires therein. One of the control wires connects to one side of speed switch 136 and by this wire it is connected to the speed solenoid 124. The other side of speed switch 136 is connected between the run switch 102 and the safety switch 122. Therefore if the engine switch is in an off position the speed solenoid is inoperative but once the engine is running the speed solenoid will be operative and if closed the speed solenoid will govern the engine at operating speed.
Also one of the wires in the electric cable 134 carries B+ voltage to remote run switch 138 and remote start switch 140. These two remote switches are, in many respects, the same as the key switch. I.e., when the remote switch 138 is open is the same as when the run switch 102 is open, i.e., there is no connection to the low amperage connection 110 of the run solenoid 106 and therefore the engine will not run. When the remote run switch is closed it is connected parallel to the run switch 102 and therefore the engine runs the same. It is possible to place these two switches in parallel inasmuch as the amperage through the run circuit is very low, about 0.4 amp, and therefore even though it goes through about 250 feet of wire through remote cable 134 that there will be negligible voltage drop and sufficient voltage for the purpose of running the hour meter 120 and maintaining run solenoid 106.
Start relay 142 is mounted at the engine. The start relay has relay switch 144 which is connected parallel to the start switch 104. The start relay 142 has relay coil 146 by which the relay switch 144 is closed when the coil is activated. The coil is activated by the remote start switch 140. The remote start switch being connected between the B+ wire and the relay coil 146. Therefore since the relay switch 144 is mounted upon the engine itself there is only a few inches of wire between the battery B+ to the starter activating circuit 114.
The two other wires in the 125 foot cable are a ground wire and a light wire. The light wire is attached to the low amperage connection 110 of the run solenoid 104. Indicator light 148 is connected between these two wires which is to say, is electrically connected between the low amperage connection 110 upon the run solenoid 106 and the ground. Therefore, any time the safety switch 122 is closed, which is to say any time the diesel engine is running, the indicator light will be burning. Therefore the indicator light will indicate by its being lighted that the diesel engine has started and that the operator on the rig platform can release the remote start switch 140, inasmuch as it is started. Also, of course, any time that it is out he could start again.
FIG. 10 shows the panel 132 which is installed with the remote control unit and to which, in this particular instance, the hour meter 120 is attached. Also attached to this is plug 152 by which the engine end of the 125 foot cable 134 is connected. The connections from the plug 152 normally go to connection board 154 where they are connected to wires extending to other parts of the engine. Also the relay 142 is mounted upon this board. For convenience, the plug 152 may be a conventional plug as is often used on trucks to make electrical connections to truck trailers.
The embodiment shown and described above is only exemplary. I do not claim to have invented all the parts, elements or steps described. Various modifications can be made in the construction, material, arrangement, and operation, and still be within the scope of my invention.
The restrictive description and drawings of the specific examples above do not point out what an infringement of this patent would be, but are to enable one skilled in the art to make and use the invention. The limits of the invention and the bounds of the patent protection are measured by and defined in the following claims. | A vacuum tank is used to suck slop over 100 feet from a basin attached to the well head of an oil well. A vacuum is initiated in a vacuum tank by a vacuum pump and maintained when liquid flows into the vacuum tank by pumping liquid from the vacuum tank into a holding tank. The liquid from the holding tank is transferred to a truck tank by which it is carried to a place of disposal. The vacuum pump and liquid pump attached to the vacuum tank are powered by a diesel engine through a hydraulic power transmission system. The diesel engine is remotely controlled from the well-head area by a remote control which operates a starting relay at the diesel engine and also which regulates the speed between idle and operating speeds. The remote unit also has a light which indicates if the diesel engine is running. | 4 |
FIELD OF THE INVENTION
The present invention relates generally to vacuum processing chambers and more particularly to a method and apparatus for abatement of reaction products such as perfluorocarbons and hydrofluorocarbons in vacuum processing chambers.
BACKGROUND OF THE INVENTION
Various types of equipment exist for semiconductor processing such as plasma etching, ion implantation, sputtering, rapid thermal processing (RTP), photolithography, chemical vapor deposition (CVD), and flat panel display fabrication processes wherein etching, resist stripping, passivation, deposition, and the like, are carried out. For example, a vacuum processing chamber may be used for etching and chemical vapor deposition of materials on substrates by supplying an etching or deposition gas to the vacuum chamber and by application of radio frequency (RF) energy to the gas. Electromagnetic coupling of RF energy into the source region of a vacuum chamber is conventionally employed to generate and maintain a high electron density plasma having a low particle energy. Generally, plasmas may be produced from a low-pressure process gas by inducing an electron flow which ionizes individual gas molecules through the transfer of kinetic energy through individual electron-gas molecule collisions. Most commonly, the electrons are accelerated in an electric field, typically a radiofrequency electric field produced between a pair of opposed electrodes which are oriented parallel to the wafer.
Plasma generation is used in a variety of such semiconductor fabrication processes. Plasma generating equipment includes parallel plate reactors such as the type disclosed in commonly owned U.S. Pat. No. 4,340,462, electron cyclotron resonance (ECR) systems such as the type disclosed in commonly owned U.S. Pat. No. 5,200,232, and inductively coupled plasma (ICP) or transformer coupled plasma systems such as the type disclosed in commonly owned U.S. Pat. No. 4,948,458.
Due to the tremendous growth in integrated circuit production, the use of vacuum processing chambers has increased dramatically in recent years. The use of vacuum processing chambers may seriously affect the environment, however, because perfluorocarbons (PFCs) are widely used in plasma etch and plasma-enhanced CVD equipment. PFCs are highly stable compounds which makes them well suited for plasma processing. However, PFCs also significantly contribute to global warming and are not destroyed by scrubbers or other conventional emission control equipment used in vacuum processing chambers. Although there are many gasses which cause global warming, PFCs and hydrofluorocarbons (HFCs), both of which are referred to hereinafter as “fluorocarbons”, also used in plasma processing, have particularly high global warming potentials (GWPs). For example, CF 4 , C 3 F 8 , SF 6 , NF 3 , and C 2 HF 5 all have GWPs of over 3000, and C 2 F 6 , SF 6 , and CHF 3 have GWPs of over 12,000. By contrast, carbon dioxide, a well-known greenhouse gas, has a GWP of 1. In addition, because of their stability, PFCs have a very long lifetime. For example, the lifetimes of CF 4 and C 2 F 6 are 50,000 and 10,000 years, respectively. Thus, collectively, these process gasses can have a significant impact on the environment.
To reduce the impact of PFCs on the environment, several conventional methods for abating PFCs from vacuum processing chambers have been proposed, including process optimization, chemical alternatives, and destruction/decomposition. Process optimization involves the refinement of system parameters to achieve the desired process while using the minimum amount of PFCs. Process optimization is desirable because it reduces chemical costs and emissions and may increase throughput and prolong the life of internal components of the reactor. However, process optimization does not provide a complete solution since it does not involve the abatement of PFCs once they are used in the system. Thus, although the amount of PFCs used is reduced by process optimization, the PFCs that are used are ultimately emitted into the environment.
Chemical alternatives to using PFCs are desirable because they eliminate the problem of PFC emissions entirely. However, to date, research is still underway to uncover more effective and environmentally sound chemical alternatives.
There are two basic categories for conventional destruction/decomposition techniques. The first category involves abatement performed on the atmospheric side of the system, either at each tool or on a large scale for multiple tools, after the gasses have passed through the pumping system. On the atmospheric side, there are several possibilities, including water scrubbers, resin beds, furnaces, flame-based burn boxes, and plasma torches. All of these except burn boxes and torches are ineffective against many of the highly stable PFC compounds.
Burn boxes have been shown to be inefficient abatement devices, unless very large amounts of reactant gases such as hydrogen, methane, or natural gas are flowed through the burn box. This makes these devices very expensive to operate, and environmentally unfriendly.
Plasma torches on the atmospheric side could be more effective; however, very large and expensive, not to mention dangerous, torch facilities would be required to abate what would be a small concentration of PFCs in a very high flow of tool effluent. This inefficiency is exacerbated by the addition of large amounts of nitrogen, used as a diluent in vacuum pumps and as a purge gas in many tool operations.
The second general category of destruction/decomposition techniques involves abatement performed under a vacuum upstream of the pumping system. Plasma destruction is one method, for example, in which a device is employed to treat the exhaust from the tool upstream of the pump before nitrogen purge dilution has taken place. In plasma destruction, energy is applied to the reaction gasses to create a plasma in which the gasses are ionized. The PFCs become unstable at the high energy state, and are consequently broken down into smaller molecules which are less detrimental to the environment.
Examples of devices for plasma destruction include the ETC Dryscrub and the Eastern Digital Post-Reaction Chamber (PRC). The ETC Dryscrub is a flat spiral chamber. The gases come in at the outer end of the spiral, circle around, and eventually exit through the center of the spiral. The spiral is an RF electrode operated at 100 kHz. The purpose of the reactor is to dissociate exhaust gases coming from a CVD system so that any remaining solid-producing gases are reacted onto the walls of the spiral. Tests performed on the ETC Dryscrub reactor, however, resulted in a relatively ineffective abatement of C 2 F 6 , the test gas. In addition, the main reaction product was another greenhouse PFC gas, CF 4 , and most of the secondary products were also greenhouse gasses. The Eastern Digital PRC is essentially the same as the ETC Dryscrub, and yields similar results. These devices are both inefficient at plasma abatement and have low plasma densities and dissociation rates.
Another known method for plasma destruction, in which CF 4 , C 2 F 6 , and SF 6 may be abated, involves the use of a microwave plasma reactor. Microwave sources, however, are expensive and complex. They also have small skin depths, so they tend have an axial region where there is no plasma, through which unabated gases escape. This can be compensated by inserting a “plug”, but the plug then reduces the fluid conductance of the device, which in turn adversely affects the performance of the pumping system.
SUMMARY OF THE INVENTION
According to an exemplary embodiment of the invention, an apparatus for abating fluorocarbons in gas reaction products from a vacuum processing chamber comprises a dielectric tube in fluid communication with an outlet port of the vacuum processing chamber, a coil disposed around the dielectric tube, and an RF source, connected to the coil, for supplying RF energy to the coil and destroying fluorocarbons in the gas.
By applying RF power to the coil, an inductively coupled plasma (ICP) is generated in the dielectric tube which breaks down the reaction products from the vacuum processing chamber. The abatement device provides several advantages over prior systems. For example, in contrast to many prior designs, the abatement device can be made to be simple, compact, inexpensive, efficient, reliable, and require little or no operator or control system intervention. The abatement device also provides a high plasma density, high dissociation rate operation, and a skin depth which is adjustable through the frequency. This results in efficient abatement without compromising foreline conductance.
According to alternative embodiments, the plasma may be generated with grids or coils disposed in the reaction chamber perpendicular to the flow of reaction products from the vacuum processing chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the present invention will be more readily understood upon reading the following detailed description in conjunction with the drawings in which:
FIG. 1 is an illustration of an abatement apparatus according to an exemplary embodiment of the invention;
FIG. 2 is an illustration of one embodiment of a reactor tube;
FIG. 3 is an illustration of one embodiment of the plasma reactor of FIG. 1 which includes the reactor tube of FIG. 2 ;
FIG. 4 is an illustration of the exemplary matching network of FIG. 3 ;
FIG. 5 is an illustration of another embodiment of the plasma reactor of FIG. 1 ;
FIG. 6 is an illustration of another embodiment of the plasma reactor of FIG. 1 ; and
FIG. 7 is an illustration of an exemplary scrubber shown in FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 , a fluorocarbon (e.g. perfluorocarbon and/or hydrofluorocarbon) abatement apparatus according to an exemplary embodiment of the invention generally comprises a plasma reactor 100 which includes an RF power source 102 for supplying power to the plasma reactor 100 . The abatement apparatus is preferably installed in the foreline 104 of each vacuum processing chamber at the point of use. According to a preferred embodiment, the abatement apparatus comprises a section of dielectric tubing replacing a section of foreline. The abatement apparatus shown in FIG. 1 may thus be installed downstream of a vacuum processing chamber 106 . According to a preferred embodiment, a coil wrapped around the dielectric tube is driven with RF power in order to generate an inductively coupled plasma (ICP) within the foreline. The plasma breaks down reaction products from the vacuum processing chamber such as PFCs and HFCs.
The plasma reactor 100 preferably includes a cooling mechanism 108 , such as a water cooler or a fan, for dissipating heat created by the plasma in the plasma reactor 100 . For example, the plasma reactor 100 may include a water jacket in which water is circulated to absorb heat in the plasma reactor 100 , or a fan.
The abatement apparatus may also include a reactant mixing chamber 110 upstream of the plasma reactor 100 for mixing a reactant into the gas flow before it reaches the plasma reactor 100 . The reactant mixing chamber 110 is supplied with the reactant by a reactant source 112 . According to a preferred embodiment, water vapor is used as the reactant to supply hydrogen and oxygen to the reaction. The reactant may also include a compound such as H 2 , CH 4 , or other hydride to supply hydrogen to the reaction, and O 2 to supply oxygen to the reaction.
A scrubber 114 can be installed downstream of the plasma reactor 100 to remove HF to prevent damage of the remaining foreline and/or mechanical pump by HF which is a highly corrosive gas. The scrubber 114 may include a material such as Si or W in the form of pellets, beads, chunks, lines, baffles, screens, etc., which reacts with HF. Downstream of the scrubber, an emission monitoring or sampling unit 116 may be provided to monitor the content of the effluent gasses.
FIGS. 2 and 3 are illustrations of a plasma reactor 100 A according to a preferred embodiment of the invention. The plasma reactor 100 A may generally comprise a dielectric tube 120 through which reaction products from the vacuum processing chamber 106 flow. The dielectric tube 120 is preferably divided into three sections, as shown in FIG. 2 . The middle section 122 preferably comprises quartz because of its ability to withstand high temperatures. Two end sections 124 , which are preferably made of glass, are sealed to the quartz tube 122 . The glass end sections 124 are also sealed to a metal foreline tube 126 , which can be a standard ISO NW50 flange. The glass end sections 124 are provided because it is difficult to bond quartz directly to metal.
According to one embodiment, the tube shown in FIG. 2 is about 13 inches long from flange to flange with an inner diameter of about 2 inches and an outer flange diameter of about 3 inches. The quartz section 122 may be about 10 inches long and the two glass sections 124 may each be 2 inches long. These dimensions are of course provided only as an example and are not intended to be limiting.
As shown in FIG. 3 , a coil 130 is provided to generate a high density plasma source which efficiently abates PFCs and other products from the vacuum processing chamber 106 . The coil 130 preferably encircles the inner quartz section 122 but not the glass end sections 124 so that the glass end sections 124 remain at a lower temperature.
FIG. 3 shows the exemplary plasma reactor 100 A implemented as part of a vacuum processing apparatus. The foreline 104 of the apparatus is at low pressure and contains reaction products from the vacuum processing chamber. The pressure inside the dielectric tube may range from about 30 mTorr to 3 Torr, for example, and preferably is about 200 mTorr.
A bellows 134 may be provided between the foreline 104 and the plasma reactor 100 and may be attached to the foreline 104 with a flange 136 . The bellows 134 provides strain relief to the dielectric tube 120 of the plasma reactor 100 A. Thus, any strain caused by movement of the foreline 104 with respect to the plasma reactor 100 A may be alleviated with the flexible bellows 134 so that the dielectric tube 120 of the plasma reactor 100 A is not damaged. The dielectric tube 120 can be further protected by securely attaching it to the rigid enclosure 136 in which it is located. The walls of the rigid enclosure 136 , which may be metal and which are fixed to the dielectric tube 120 , provide additional resistance to strains imparted on the dielectric tube 120 by movement of the foreline 104 .
The apparatus may also include an RF shielding seal 138 at the junction between the reactor tube 120 and the rigid enclosure 136 in which the reactor tube 120 is located. The RF shielding seal 138 prevents RF radiation generated by the coil 130 from interfering with nearby electronic devices. An RF feed through connector 140 may be installed on the enclosure 136 to transmit RF power to the interior of the enclosure 136 .
To control the power applied through the coil 130 and to adjust the resonant frequency of the coil 130 , a matching network 142 can be provided. The matching network 142 is preferably simple and inexpensive. As shown in FIGS. 3 and 4 , the matching network 142 may include a first variable capacitor C 1 connected at one side to ground and at the other side to the RF power source 102 and to one end of the coil 130 . A second variable capacitor C 2 may be connected between ground and the other end of the coil 130 . The capacitance of the variable capacitors C, and C 2 may be adjusted in any suitable manner, such as with knobs 143 , to adjust the circuit resonance frequency with the frequency output of the RF generator 102 and to cancel the inductive reactance of the coil 130 . Impedance matching maximizes the efficiency of power transfer to the coil 130 . Those skilled in the art will recognize that other types of matching networks 142 can be used in conjunction with the present invention.
When the coil 130 is powered by the power source 102 , two examples of the chemical reactions of two PFCs, C 2 F 6 and SF 6 are as follows:
EXAMPLE 1
C 2 F 6 ------->CF 3 +CF 3 O 2 ------->O+O COF 2 ------->COF+F CO 2 ------->CO+O F 2 ------->F+F COF+O------->CO 2 +F CF 3 +O------->COF 2 +F CF 3 +CF 3 +M------->C 2 F 6 +M O+O+M------->O 2 +M COF+F+M------->COF 2 +M CO+O+M------->CO 2 +M F+F+M------->F 2 +M CO+F+M------->COF+M
EXAMPLE 2
SF 6 +O 2 ------->SO 2 +3F 2 SF 6 +O 2 ------->SO 2 F 2 +2F 2
According to one embodiment of the invention, a reactant injector 110 is provided upstream of the plasma reactor, as shown in FIG. 1 . The reactant injector 110 delivers chemicals with which to react away the PFC compounds, which otherwise could simply recombine downstream of the plasma reactor. The preferred embodiment is a water vapor injector. The hydrogen from the water reacts with the fluorines of the PFCs to produce HF. The HF may then be removed either by the scrubber chamber 114 upstream of the pump or by a conventional scrubber on the atmospheric side. The oxygen reacts with carbon, sulphur and/or nitrogen to produce COx, SOx and NOx, which are less harmful global warning gases than PFCs, and which may be removed from the emission stream by scrubbers. Various hydrides may also be produced and removed by scrubbing, as well as polymers and inorganic solids which will deposit on the reactor walls. The reactor, therefore, is preferably designed to be easy to clean or replace. Water vapor is preferred as the reactant because it is much less expensive than the reactants H 2 , CH 4 or other hydrides and O 2 commonly used in abatement systems to supply hydrogen and oxygen to the reaction. The flowrate of the total reactant (e.g. water vapor, H 2 , CH 4 and/or O 2 ) supplied by the reactant source 112 may be approximately equal to the flowrate of the process gasses from the vacuum processing chamber, for example 50-1000 cubic centimeters at standard temperature and pressure per minute. The reactant or reactants are preferably supplied in an amount effective for minimizing recombination of the dissociated PFC's.
Downstream of the plasma reactor 100 may be a scrubber chamber 114 or section of foreline which contains materials that react with the HF, such as Si or W in the form of pellets, beads, chunks, liners, baffles, screens, etc., as shown in FIGS. 1 and 7 . In FIG. 7 , the scrubber chamber 114 includes an inner section 115 of porous HF reactive materials such as Si or W in the form of mesh, gravel, etc. The scrubber chamber 114 also includes an outer wall 117 which comprises HF reactive material. The provision of such a chamber 114 reduces the likelihood of damage of the remaining foreline and/or mechanical pump by HF, which is a highly corrosive gas. Although HF is easily handled by a scrubber on the atmospheric side, the lifetime of the vacuum plumbing and pumps can be increased significantly by providing a scrubber chamber 114 upstream of the vacuum plumbing and pumps.
According to another embodiment of the invention, the plasma reactor may comprise conductive elements inside the foreline to generate a plasma. As shown in FIG. 5 , the elements of the plasma reactor 100 B may be in the form of conductive grids 150 through which the gases flow. Adjacent grids 150 are oppositely charged with an RF generator 152 to generate a capacitive plasma. The reaction products, e.g., PFCs, are unstable in the high energy plasma, and are consequently reacted into smaller, less harmful molecules as described above. The grids 150 are preferably planar with the plane of the grid oriented perpendicular to the flow of reaction products from the vacuum processing chamber. To generate a capacitive plasma, at least two grids 150 are used. To further enhance the effectiveness of the plasma reactor, additional grids 150 can be provided. The additional grids alternate in polarity so that each adjacent pair of grids 150 acts as a capacitor. The grids 150 may comprise a plasma resistant material for a long lifetime. Alternatively, the grids may comprise a consumable material or materials for enhanced abatement capacity.
The grids 150 are preferably disposed in a chamber 154 which has a larger cross sectional area than the cross sectional area of the foreline. In this way, the fluid conductance of the plasma reactor 100 B is not compromised. In addition, a fan or other cooling device can be provided to dissipate heat created by the conductive grids 150 . As in the previous embodiment, a matching network 156 can be provided to maximize or control the power delivered to the grids 150 .
According to another embodiment of the invention, an exemplary plasma reactor 100 C comprises at least one and preferably two or more transformer coupled plasma coils. The transformer coupled plasma coils 160 , as shown in FIG. 6 , have a generally spiral, planar configuration and are preferably oriented such that the plane of the coil is perpendicular to the flow of reaction products. The transformer coupled plasma coils 160 are coupled, preferably through a matching network 166 , to an RF generator 162 . By resonating a radiofrequency current through the coils 160 , a planar magnetic field is induced which induces a generally circular flow of electrons within a planar region parallel to the plane of the coil 160 . The circulating electrons create a plasma by ionizing individual gas molecules through the transfer of kinetic energy from individual electron-gas molecule collisions.
The reaction products, e.g., PFCs, are unstable in the high energy plasma, and are consequently reacted into smaller molecules as described above. Preferably, at least two coils 160 are provided so that the period of time during which the reaction products are in the plasma state is sufficiently long to effectively break down the reaction products. The provision of additional coils 160 thus increases the size of the region which the plasma occupies so that for a given flowrate, the reaction products are in the plasma state for a longer time. The transformer coupled plasma coils can comprise plasma resistant materials for a long lifetime. Alternatively, the transformer coupled plasma coils can comprise a consumable material or materials for enhanced abatement capacity. So that the fluid conductance of the apparatus is not compromised, the chamber 164 in which the transformer coupled plasma coils 60 are located can have an enlarged cross sectional area perpendicular to the flow. A fan or other cooling mechanism can be provided to dissipate heat generated by the coils 160 of the plasma reactor 100 C.
Those skilled in the art will recognize that exemplary embodiments of the present invention provide significant advantages in the abatement of reaction products such as fluorocarbons from a vacuum processing chamber. For example, in contrast to many prior designs, the reactor can be made to be simple, compact, inexpensive, efficient, reliable, and require little or no operator or control system intervention. The plasma reactor also provides a high plasma density, high dissociation rate operation, and a skin depth which is adjustable through the frequency. This results in efficient abatement without compromising foreline conductance. Also, in the event that an abatement device fails, only one tool is affected, rather than an entire section of a processing system.
The above-described exemplary embodiments are intended to be illustrative in all respects, rather than restrictive, of the present invention. Thus the present invention is capable of many variations in detailed implementation that can be derived from the description contained herein by a person skilled in the art. All such variations and modifications are considered to be within the scope and spirit of the present invention as defined by the following claims. | An exemplary method and apparatus for abating reaction products from a vacuum processing chamber includes a reaction chamber in fluid communication with the vacuum processing chamber, a coil disposed about the reaction chamber, and a power source for supplying RF energy to the coil. The coil creates a plasma in the reaction chamber which effectively breaks down stable reaction products from the vacuum processing chamber such as perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) which significantly contribute to global warming. According to alternative embodiments, the plasma may be generated with grids or coils disposed in the reaction chamber perpendicular to the flow of reaction products from the vacuum processing chamber. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to foreign European Patent Application EP 11007363.2, filed on Sep. 9, 2011, the disclosure of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
The invention relates to a link chain made of chain links that are connected to one another by means of chain joints, whereby the chain joint comprises at least one chain joint bearing and a pin that is guided in the chain joint bearing in a pivotable manner and that is in contact with the chain joint bearing, whereby at least one bearing surface of the pin and/or of the chain joint bearing is provided with a hard material layer and the hard material layer is applied by means of a PVD process.
BACKGROUND
Link chains with chain links that are connected to one another by means of chain joints are in use in the state of the art in various forms. To a predominant extent, these are chains in which an inner chain link made of two parallel inner plates alternates with an outer chain link that consists of two outer plates connected to each other by means of two pins. A chain joint is thereby formed by means of a pin and the plates of the inner chain link which are pivotable on said pin. In the event that the chain has bushings, the chain joint is formed by the bushing and the pin fed through and held in a pivotable manner.
In use as driving chains or conveyor chains, particularly the area of the chain joint is highly loaded so that there is a great demand here with respect to a wear-resistant bearing surface. In addition to the use as driving chains or conveyor chains, link chains are again increasingly being used in the automotive industry for controlling the valve operating mechanism of internal combustion engines. The requirements on the wear resistance are thereby particularly high, because in internal combustion engines there are very frequent load-cycle changes and only very restricted access for maintenance or replacement of the chain. Moreover, there is an endeavour to design the chain so that it is as small and has as little weight as possible, which further increases the load on the individual chain elements.
In order to achieve the necessary wear resistance and to avoid elongation caused by wear, the pins and/or bushings of conventional link chains are subjected to heat treatment, e.g., hardening and tempering, carbonisation, carbonitriding, etc., or they are provided with a carbide layer. In spite of heat treatment of the joint components and/or the formation of a carbide layer on the joint surfaces, wear problems and elongation caused by wear occur, particularly in the use as timing chains in an internal combustion engine, that reduce the engine's reliability or necessitate an expensive exchange of the chain.
A link chain of this category is known from DE 10 2006 052 869 A1. In this, a link chain is disclosed whose pin and/or bushing is provided with a PVD hard material layer, whereby the pin and/or the bushing consists of a base material made of a high carbon steel with a carbon content between 0.4 weight % and 1.2 weight % that supports the PVD hard material layer. The disclosed PVD hard material layer can consist both of metal hard materials and of non-metal hard materials. All carbides, nitrides, carbonitrides, borides, and silicides of the transition metals come into question as metal hard materials. Coming into question as non-metal hard materials are, for example, diamond and DLC (diamond-like carbon), as well as corundum, boron carbide, cubic boron nitride, silicon carbide or aluminium nitride.
Such hard material layers represent an improvement over the previously used coating methods. Nevertheless, due to the aforementioned high loads and the trend towards smaller dimensioning of engines with simultaneous power increase, there is a demand for chains capable of bearing even greater loads.
PVD methods furthermore have the problem that the coating material deposits not only on the objects to be coated, but also in the coating system. In the case of the PVD method (Physical Vapour Deposition), so-called targets are used that consist of the material that is to be deposited on the component to be coated. By means of different methods, it is possible to separate the coating material from this target so that it arrives as a gaseous particle flow on the surface of the component to be coated and forms a coating. Here it is wished, on the one hand, that the targets consist only of the elements that later should also be deposited on the end product. Moreover, one objective is to keep the material combinations that later are deposited on the end product at a low number. This simplifies the assembly or production of the targets and consequently also minimizes the complexity of the unwanted contamination of the coating chamber.
SUMMARY OF THE INVENTION
It is therefore the object of the invention to enhance a link chain with respect to its wear characteristics and additionally to state a coating method that is improved with respect to previous coating methods.
The object is solved with a link chain made of chain links that are connected to one another by means of chain joints, whereby a chain joint comprises at least one chain joint bearing and a pin that is guided in the chain joint bearing in such a manner that it can pivot and that is in contact with this chain joint bearing, wherein at least one bearing surface of the pin and/or of the chain joint bearing is provided with a hard material layer and the hard material layer is applied by means of a PVD process, wherein the hard material layer is formed from a compound that comprises at least a first and a second metal and a non-metal, wherein selected as the non-metal is at least one of the materials C, N or Si and the first metal and the second metal are selected from the materials Cr, Mo, V, W, Ti, Cu, Zn, Zr, Ta, Nb, Al, B, Hf, wherein the first and the second metal differ from each other, and the first metal is present in the hard material layer in a crystal structure that differs from the crystal structure of the second metal.
The object is also solved with a method for coating a bearing surface by coating with a hard material layer a bearing surface of a pin and/or of a chain joint bearing for a chain, wherein the hard material layer is applied by means of a PVD process and is formed from a compound that comprises at least a first and a second metal and a non-metal, wherein at least one of the materials C, N or Si is selected as the non-metal and the first metal and second metal are selected from the materials Cr, Mo, W, Ti, Cu, Zn, Zr, Ta, Nb, Al, B, V, Hf, wherein the first metal and the second metal differ from each other, and the first metal is present in the hard material layer in a crystal structure that differs from the crystal structure of the second metal.
The pin forms a friction pairing with the chain joint bearing. To reduce the friction in the chain joint bearing with the help of the hard material layer, it is sufficient if one of the two elements, i.e., the pin or the chain joint bearing, is provided with the hard material layer. Both could likewise also be coated. The hard material layer consists of a compound that comprises at least three materials. These are a first and a second metal, as well as a non-metal. The non-metal is selected from the group of carbon (C), nitrogen (N) or silicon (Si). The first metal and the second metal are selected from the materials chromium (Cr), molybdenum (Mo), vanadium (V), tungsten (W), titanium (Ti), copper (Cu), zinc (Zn), zirconium (Zr), tantalum (Ta), niobium (Nb), aluminium (Al), boron (B) and hafnium (Hf).
The first metal and the second metal thereby differ from each other. The first and the second metal form crystalline structures in the hard material layer. The first metal and the second metal are thereby selected in such a way that these have crystal structures that differ in the hard material layer in combination with the non-metal. Known as typical crystal structures for metals are the face-centred cubic crystal structure (fcc), the hexagonal crystal structure (hex) and the tetragonal crystal structure (tetr).
It has been seen that such combinations of a non-metal with two metals, each with a different crystal structure, lead to a layer with a very high level of hardness. This can be attributed to the fact that no homogenous layer composition results, and instead there are individual defects in the layer configuration, as a result of which a so-called crystal mismatch exists with a hardening increase and/or grain refinement. The result is consequently a generation of alternating combinations of crystal structures of the individual material phases in the layer: e.g., cubic with hexagonal or tetragonal structures, body-centred cubic with face-centred cubic structures.
Alternatively, it can be provided that one of the non-metals carbon, nitrogen or silicon is the significant reactant. This can be controlled by means of the provision of the respective quantity of a material.
Furthermore it can be provided that the hard material layer has a gradated configuration with respect to the non-metal portion, the hardness or the internal stress portion. The term “gradated” is thereby to be understood such that it does more than just indicate the configuration of a coating of different layers that can be delimited from one another. There can also be a material-related non-uniform distribution present within a layer. Furthermore a gradated layer is conceivable into which a further layer is inserted, i.e., the gradation extends across the entire coating, but is, however, interrupted by a second layer. It is furthermore conceivable that a gradated layer in the coating is covered with a second layer of the second metal, whereupon a new independently gradated layer of the first metal is then again attached. As already addressed, the gradation can also have an influence with regard to the hardness or the internal stress portion. This means that the hardness level in the hard material layer has different values depending on the location.
It is furthermore conceivable that a Cr-alloy steel, e.g., 59CrV4 or 100Cr6, is selected as the base material of the pin or of the chain joint bearing. These metals have proven to be a good basis for such coatings.
One conceivable development of the link chain consists of choosing the layer thickness of the hard material layer in the range from 1 to 15 μm, preferably 1 to 10 μm. Such a layer thickness offers a sufficient protective layer in the event of long-term loading and is not too thin.
It can furthermore be provided that a sub-layer thickness of the hard material layer amounts to less than 1 μm, preferably less than 0.5 μm. Provided the hard material layer consequently is formed from individual sub-layers that can be distinguished from one another, these should amount to less than 1 μm, preferably less than 0.5 μm. In this way, it is ensured that a detachment or flaking off of individual layers is prevented.
In addition, it is conceivable that the gradated particle sizes of the hard material layer have a size of less than or equal to 100 nm, preferably of less than or equal to 50 nm. Provided that individual particle sizes are discernible in the hard material layer, these size ranges have proven to be preferred for the hardness and fatigue resistance of the hard material layer.
In addition, it is conceivable that the hard material layer has, at least in areas, a glass-like structure. To be understood as glass-like is thereby that the atoms do not form ordered structures, but instead form an irregular pattern and have only a short-range order, not a long-range order. Such glass-like structures, which are assembled from the materials used for the hard material layer, have a high level of stability as well as fatigue resistance and are thereby one of the aimed-at developments.
Alternatively, it can be provided that the gradated layer hardness levels of the hard material layer are from 2000 to 4000 HV or 4000 to 7000 HV. These ranges of the layer hardness levels are preferred in the normally occurring usage conditions for such link chains.
In addition, it is conceivable that the hard material layer is applied by means of a continuous PVD method using a through-feed method. Through-feed methods differ from batch methods in that the components to be coated are introduced to and removed from the coating chamber continuously, e.g., by means of a conveyor belt. There are consequently constantly components in the coating chamber, whereby the components are in different stages of the coating process. In batch methods, on the other hand, a certain number of components are together introduced into the chamber and removed from it again after the coating. There are therefore time periods in which there are no components in the coating chamber. In the case of batch methods, all components are additionally always in the same stage of the coating process. The through-feed method allows a significantly higher throughput and is therefore to be preferred for economic reasons.
The object according to the invention is additionally solved by a chain pin for a link chain, whereby the chain pin is provided, at least in areas, with a hard material layer of the type previously presented.
In addition, the object according to the invention is solved by a method for coating with a hard material layer a bearing surface of a pin and/or of a chain joint bearing for a chain, whereby the hard material layer is applied by means of a PVD process and is formed from a compound that comprises at least a first and a second metal and a non-metal, whereby selected as the non-metal is at least one of the materials carbon, nitrogen or silicon and whereby the first metal and the second metal are selected from the materials chromium, molybdenum, tungsten, copper, zinc, zirconium, tantalum, niobium, aluminium, boron, vanadium and hafnium, whereby the first and the second metal differ from each other, and the first metal, in combination with the non-metal, forms in the hard material layer a crystal structure that differs from the crystal structure of the second metal in combination with the non-metal.
Alternatively, it can be provided that the hard material layer is applied in a gradated configuration.
In addition, it can be provided that the PVD process runs as a continuous process in the through-feed method.
In addition, it can be provided that the components that are to be coated are fed during the coating process in a coating area in such a way that these are exposed at least in areas to different temperatures over time. In addition to the selection of the correct material combinations, the variation of the temperatures can also, to a certain extent, be used in order to support the formation of different crystal structures. The coating method is therefore adapted in such a way that even in the case of an assumed constant infeed of the individual materials, different crystal structures nevertheless form due to the variation in the temperature.
As a further variant, it can be provided that the first metal is selected from a first group and the second metal is selected from a second group, whereby at least one metal of the first group is combined with at least one metal of the second group, and whereby the first group includes chromium, molybdenum, vanadium, tungsten, and titanium and the second group includes copper, zinc, zirconium, tantalum, niobium, aluminium, boron and hafnium.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, the invention is described in more detail on the basis of the drawings. Shown are:
FIG. 1 a greatly schematised sketch of a coating device,
FIG. 2 a greatly schematised schematic diagram of the coating method,
FIG. 3 a schematic depiction of a ternary phase diagram.
DETAILED DESCRIPTION
The desired hardness of the hard material layer is achieved by means of the mixture of a non-metal with two different metals, whereby the metals differ substantially in their crystallisation structure. This means that given equal activation conditions, for example, a plasma, and given the same reactive gas compositions, the two metals form different crystal lattices. This results in a crystal mismatch with miscibility gaps, as a result of which hardening mechanisms take effect that increase the hardness of the hard material layer. Furthermore there results extreme grain refinement and a superficial friction reduction. The hard material layer according to the invention therefore has, on the one hand, hardness that is better than the hard material layers known until now and additionally reduced friction on its surface. The hard material layer is correspondingly very wear-resistant and furthermore has very good friction coefficients.
A further effect that results is a tribochemical lubricating effect of the coating materials under the operating conditions of a combustion engine. This means that the hard material layer according to the invention works optimally together with the motor oil or the additives in the motor oil in order to reduce the friction in the chain joint.
The crystal structures achieved in the hard material layer significantly depend on the ionic sizes of the selected materials. This ionic radius is fundamentally not dependent on the substance or material, but instead depends on the process. The ionic radius results from the ionisation degree of the material, whereby the relationship between the ionic radii of the materials determines the crystal structure (e.g., cubic, hexagonal, tetragonal) by way of the threshold radius base r+/r−. In order to achieve the hardest possible and most resistant possible hard material layer, the objective here is always to pair different crystal structures with one another. Consequently, for r+/r− between 1 and 0.73, crystal structures in the cubic development arise, to 0.41 octahedral and for r+/r− to 0.2, crystal structures in the tetrahedral development. Examples of possible material combinations are:
(V,Ta)C
(V,Nb)C
(V,Hf)C
(Cr,Zr)N
(Cr,Mo)N
(Cr,W)N
(Cr,Cu)N
(Mo,Cu)N
(W,Cu)N
(Mo,V)N
(Cr,V)N
(V,Nb)N
(Ti,Nb)N
The cited material combinations can be present as variants with C, Cn, SiN or SiC. The order of the materials and the proportions of the two metals are fundamentally exchangeable.
Depending on the proportion of the first metal to the second metal, the metal present in the greater quantity dominates the primary structure, i.e., a change in the dominant metal can be provided for gradation.
Furthermore, the following phases are conceivable in the layers (only a collection of examples):
CrN 1-x —MoN 1-y —Si a N b
CrN 1-x —WN 1-y
CrCN 1-x —WCN 1-y
CrN 1-x —MoN 1-y —SiC
MoN 1-x —CuN 1-y
CrN 1-x —CuN 1-y
CrN 1-x —ZrCN 1-y
ZrN 1-x —CuN 1-y
MoCu—MoN 1-x
These layers can be formed as gradient layers and/or multi-layer layers and/or nano-composition layers. A multi-layer layer is thereby to be understood as the provision of a plurality of layers that are constructed from different material combinations. In addition, gradient layers or a mixture thereof can likewise be provided, whereby the layer composition changes only gradually and no clear delimitation can be brought about between different layers. To be understood as a nano-composite layer is a layer whose structure is formed from a primary material by means of introducing one or more materials in a low quantity. For example, a nano-composite layer could be formed from CrN—MoN—SiN, whereby SiN forms the basic structure or the matrix, and CrN and MoN are incorporated in a low quantity, preferably as nano-particles.
Furthermore, due to the application of the hard material layer and its characteristics, the surface of the hard material layer has a glass-like configuration. The surface is correspondingly very low-friction with a high hardness level and resisting power.
The hard material layer can be present in a stoichiometric transition stage. Meant by this is that, e.g., the carbon or silicon portion is present in a nanoscale disperse phase, meaning it is finely distributed on a limited scale.
The hard material layer is applied using a PVD method, particularly preferably in a plasma PVD process. So-called CVD-like process support results hereby, because the non-metal materials carbon, nitrogen and silicon are, to a certain degree, involved during the PVD process in chemical reactions that turn a purely PVD process into a PVD process with elements of the CVD processes.
As already addressed, the achievable crystal structures are essentially based on the selected material combinations. In addition, the resulting crystal structures can, however, also be influenced to a certain degree by the process control. The coating system 1 ( FIG. 1 ) is therefore constructed in such a way that the process control supports the formation of different crystal structures. For this, at least one target 2 , the components that are to be coated, i.e., the pins 4 , and optionally a cooling device 5 are provided in the coating chamber 3 . Not shown is a transport device for the pins 4 that transports these through the coating chamber 3 . The transport takes place through the process chamber 3 in the through-feed method (indicated by means of the arrows 15 ). The pins 4 thereby preferably rotate around their longitudinal axis 16 .
During the PVD process, materials are released from the target 2 that move in a particle flow 6 in the direction of the pins 4 and that deposit on the surface of said pins 4 . As a rule, particle deposition takes place only on the surface of the pins that is facing the target. In order to achieve a uniform coating of the pins 4 , these are therefore fed in a rotating manner through the coating chamber 3 , which is indicated by the arrows 7 . The entire surface of the pins 4 is correspondingly exposed to the particle flow 6 , so that uniform deposition is achieved. If desired, the pins can also be covered in areas or otherwise withdrawn from the particle flow, so that a hard material coating results only on the desired surfaces.
All PVD methods have in common the fact that a certain heat or heating of the target is necessary in order to generate a particle flow 6 . The heat or high temperature is necessary thereby in order to achieve a sufficiently high particle energy that brings about a release of the particles from the target. The sides 8 of the pins 4 facing the target 2 are correspondingly exposed to a higher temperature than the sides 9 of the pins facing away from the target. The sides 8 and 9 can correspondingly also be called the day side 8 and the night side 9 . As a result, it follows that the day sides 8 of the pins 4 have a higher temperature than the night sides 9 , which in turn influences the achievable crystal structures. The temperature is indicated in the figures by means of schematised thermometers for a high temperature 14 and a low temperature 15 .
As shown in FIG. 3 , so-called ternary phase diagrams apply to material combinations with three materials. In the shown example, the three materials are a non-metal (NMe), a first metal (Me 1 ) and a second metal (Me 2 ). Different crystal structures thereby result depending on the proportions and on the associated process conditions, particularly the temperature. The ternary phase diagram of FIG. 3 is used here only to depict the principle and does not refer to the previously mentioned material combinations.
In the phase diagram of FIG. 3 , a plurality of areas 11 a , 11 b , 11 c , 11 d are designated, each of which marks different crystallisation structures. In the shown example, the stoichiometric point 10 of a layer or material combination is located close to the boundary between area 11 a and the areas 11 b and 11 d.
The stoichiometric point 10 can normally be changed only comparatively slowly, for which reason other process parameters, such as, e.g., the temperature, present themselves for influencing the hard material layer. By changing the reaction or process conditions on the moved part, it is therefore possible to shift the phase boundaries between the areas 11 a , 11 b , 11 c and 11 d in such a way that the phase boundaries shift beyond the stoichiometric point 10 . The shifting of the phase boundaries between the areas 11 a , 11 b , 11 c , 11 d is indicated in FIG. 3 with the arrows 12 and 13 . As already addressed, crystal structures often form in dependence on the energy supply, i.e., the temperature. Consequently, if, e.g., a layer is deposited that is composed of cubic MoN 1-x and CrN 1-y , the cubic MoN 1-x can, by means of a temperature change, change to hexagonal MoN 1-x whereby the CrN 1-y phase remains stable. In principle, one or two individual phases of a layer can change, meaning one or two phase boundaries can shift.
The reaction conditions that need to be changed for this depend on the selected material combinations and can therefore not be described here in general terms. Possible influential measures are, however, a change in the temperature or in the proportions.
In addition, the change to the other side of the phase boundary can also still be forced by means of the shifting of the stoichiometric point, for example, by varying the supply of the reactive gas, i.e., of the non-metal.
The shown coating system 1 has a cooling device 5 for influencing the temperature of the pins 4 in the coating area. During the rotation of the pins 4 , an area of the surface lands in the so-called night area 9 , where said surface cools.
A different crystal structure correspondingly results in the case of the selection of the respective material combination and the associated temperatures. The cooling can therefore be adapted in such a way that the desired end-point between two crystal structures is always reached. Depending on the selected material combinations, it is also possible that no additional cooling is necessary and the slightly lower temperature due to the greater distance of the night area from the heated target is alone sufficient. However, steep temperature gradients, i.e., a swift and significant change in temperature, are preferred.
During the coating process, a point on the surface of the pin wanders from the night side so to speak through a twilight zone and into the day side and then back to a twilight side and into the night side. The surface of the pin correspondingly begins to heat up from the time of the transition into the twilight zone until it reaches a maximum value in the day side and it begins to cool off again during the transition into the twilight zone. The temperature of the pin surface is therefore subject to constant change, for which reason the hard material layer deposited on it can form different structures.
For such coatings, a base material of Cr-alloy steel, e.g., 59CrV4, 100Cr6 or higher alloyed, is particularly suitable. The coating temperatures preferably lie in the range from 100° C. to 500° C., whereby there is an endeavour to reach a layer thickness of from 1 to 10 μm. Individual sub-layer thicknesses can be less than 0.5 μm. The gradated particle sizes can be 50 nm or less.
In the event that nitrogen and silicon are used as non-metal partners, a hardness level in the range from 2000 to 4000 HV can be achieved. In the event that carbon is used as the non-metal partner, 2000 to 4000 HV can likewise be achieved, whereby values from 4000 to 7000 HV can also be achieved.
In summary, it can be said that the one-sided arrangement of the coating source toward the products and the cooling of the products from the other side and the rotation of the pins allows swift heating and cooling processes at the pin surface. A virtual observation point on the pin surface wanders from the hottest disposition directly opposite the source (i.e., the target) in the direction of the coating horizon, where the energy application is already significantly less, back into the night area, where a cooling process starts that is caused either by active cooling with a cooling device or by the lower ambient temperatures. With the end of the night area, the reheating starts from the dawn horizon. This allows faster changes in the working point in the ternary phase environment and in the ternary phase environment itself. The change speed can be selected via the process.
The presented hard material layer and the method for applying the same can be applied to all types of chains. In particular, bush chains and other types of chains, such as, e.g., toothed chains, can be equipped with it. | A link chain is made of chain links connected by chain joints, a chain joint comprising at least one bearing and a pin guided in a pivotable manner and in contact with this chain joint bearing. At least one bearing surface of the pin or chain joint bearing has a hard material layer applied by a PVD process, formed from a compound including at least two metals and a non-metal, at least C, N or Si being selected as the non-metal and the two metals being selected from Cr, Mo, W, Ti, Cu, Zn, Zr, Ta, Nb, Al, B, V, Hf, whereby the two metals differ from each other and the first metal is present in the hard material layer in a crystal structure that differs from the crystal structure of the second metal. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application 62/294,117, filed Feb. 11, 2016, the entirety of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention pertains to portable and/or temporary outdoor structures for storing or supporting persons and/or goods, and particularly to tents and like structures that are capable of being suspended above the ground, such as from a tree by means of a rope or strap.
BACKGROUND OF THE INVENTION
[0003] In the course of camping or other outdoor recreational activities, placement or storage of persons, items, or equipment in close proximity to the ground may cause a number of problems. The ground of an outdoor environment presents many potential contaminants and/or irritants, including but not limited to water, insects, sharp objects, rocks, and dirt, which may damage tents or other items, contaminate stored food or equipment, or be offensive to campers or hikers. In certain environments, larger animals, such as bears and mountain lions, may also pose a danger to persons and items on the ground.
[0004] There is thus a need in the art for a structure that separates users and their items and equipment from the ground to protect them from damage, contamination, and other hazards.
SUMMARY OF THE INVENTION
[0005] The present disclosure provides a new and novel structure. One aspect of the present disclosure is a treepod assembly including a suspension element. The treepod assembly may be suspended from a tree or other structure by a rope or strap interconnected to the suspension element. In this manner, a bottom portion of the treepod assembly does not contact the ground. Thus, in use, a bottom portion of the treepod assembly is separated from contaminants (such as water, insects, sharp objects, rocks and dirt) that may be present on the ground. In this manner, the treepod assembly is protected from damage. Similarly, users of the treepod assembly are protected from crawling insects and other hazards present on the ground. In one embodiment, the treepod assembly includes a frame to support the users. In another embodiment, the treepod assembly is devoid of a frame. In still another embodiment, the treepod assembly comprises a platform portion. The user may position a tent on the platform. In yet another embodiment, the treepod assembly comprises an integral tent interconnected to the platform.
[0006] Another aspect of the present disclosure is a treepod assembly comprising a pocket formed between a first material layer and a second material layer. The pocket includes apertures of a predetermined size. When the treepod assembly is suspended off of the ground from a tree or other elevated structure, the apertures enable air to enter the pocket to at least partially inflate the pocket. In this manner, the pocket forms a cushion. If the strap used to suspend the treepod assembly fails, impact with the ground causes a release of the air through the apertures. The pocket protects occupants from the impact. In one embodiment, the apertures enable air to enter the pocket faster than air can exit the apertures. The apertures may include baffles to direct, or limit, the flow of air into and/or out of the pocket.
[0007] In accordance with one aspect of the present disclosure, a novel treepod assembly is provided. The treepod assembly includes, but is not limited to: (1) a pocket comprising a first layer of material interconnected to a second layer of material; (2) air apertures formed in the pocket; and (3) a suspension element interconnected to the pocket. In one embodiment, the treepod assembly further comprises a tent, an upper portion of the pocket forming a bottom portion of the tent. In another embodiment, the apertures are positioned in the upper portion of the pocket.
[0008] In accordance with still another aspect of the present disclosure, a treepod assembly is provided, comprising a tent, having a substantially rectangular footprint and comprising an internal chamber and at least one of a vent and a window, the internal chamber having at least one opening and a floor; at least one suspension element, the at least one suspension element having sufficient strength to support the weight of the treepod assembly and the at least one occupant while the treepod assembly is suspended above the ground by the suspension element from an elevated structure; and a rigid, substantially rectangular frame, wherein the floor of the internal chamber and the rigid frame are made of appropriate materials and configured to support the weight of at least one occupant. In embodiments, the at least one of a vent and a window may be substantially semicircular. In embodiments, the at least of a vent and a window may comprise at least one vent, the at least one vent being partially covered by a vent cover disposed on an external face of the tent. In embodiments, the at least one of a vent and a window may be disposed on an external face of the tent other than the face on which the at least one opening is disposed. In embodiments, the at least one suspension element may be a hook or loop disposed on a top of an external surface of the tent. In embodiments, the treepod assembly may be capable of supporting a weight of at least about 500 pounds when suspended above the ground.
[0009] The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below.
[0010] As used herein, the term “treepod assembly” refers to a structure that is able and adapted to remain securely suspended above the ground from an elevated structure while occupied by at least one person.
[0011] The phrases “at least one,” “one or more,” and “and/or,” as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
[0012] Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.”
[0013] The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.
[0014] The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein.
[0015] The Summary is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. Moreover, references made herein to “the present invention” or aspects thereof should be understood to mean certain embodiments of the present invention and should not necessarily be construed as limiting all embodiments to a particular description. The present invention is set forth in various levels of detail in the Summary as well as in the attached drawings and the Detailed Description and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements or components. Additional aspects of the present invention will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and, together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosure. It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein. In the drawings:
[0017] FIG. 1 is a perspective view of a treepod assembly according to the present invention;
[0018] FIG. 2 is a front view of a treepod assembly according to the present invention;
[0019] FIG. 3 is a back view of a treepod assembly according to the present invention;
[0020] FIG. 4 is a right side view of a treepod assembly according to the present invention;
[0021] FIG. 5 is a left side view of a treepod assembly according to the present invention;
[0022] FIG. 6 is a top view of a treepod assembly according to the present invention;
[0023] FIG. 7 is a bottom view of a treepod assembly according to the present invention;
[0024] FIGS. 8A and 8B illustrate a first embodiment of a lower assembly according to the present invention;
[0025] FIGS. 9A and 9B are top and front elevation views, respectively, of the first embodiment of a lower assembly according to the present invention;
[0026] FIGS. 10A and 10B illustrate a second embodiment of a lower assembly according to the present invention;
[0027] FIGS. 11A, 11B, and 11C are top, front elevation, and right side views, respectively, of the second embodiment of a lower assembly according to the present invention;
[0028] FIG. 12 is a 45° angle view of a treepod assembly according to the present invention;
[0029] FIG. 13 is a front view of a treepod assembly according to the present invention;
[0030] FIG. 14 is a back view of a treepod assembly according to the present invention;
[0031] FIG. 15 is a left view of a treepod assembly according to the present invention;
[0032] FIG. 16 is a right view of a treepod assembly according to the present invention;
[0033] FIG. 17 is a top view of a treepod assembly according to the present invention; and
[0034] FIG. 18 is a bottom view of a treepod assembly according to the present invention.
DETAILED DESCRIPTION
[0035] The following Components List identifies various features of the present invention by their reference numbers in the drawings.
COMPONENTS LIST
[0036] 1 Tent
[0037] 2 Suspension element
[0038] 3 Pocket
[0039] 4 Opening
[0040] 5 Internal chamber
[0041] 6 Window and/or vent
6 a Window 6 b Vent
[0044] 7 First layer of material
[0045] 8 Second layer of material
[0046] 9 Aperture
[0047] 10 Rod
10 a Straight rode 10 b Arcuate rod
[0050] 11 Connector
[0051] 12 Vent cover
[0052] 13 Frame
[0053] Referring now to FIGS. 1-11 , a treepod assembly of an embodiment of the present disclosure is illustrated. The treepod assembly generally comprises a tent 1 , a suspension element 2 , and a pocket 3 . Although not illustrated, the treepod assembly may also include attachment points for interconnection of stability lines. The attachment points may comprise hooks. Additionally or alternatively, the attachment points may comprise loops of fabric or cord. In one embodiment, the treepod assembly includes at least three attachment points spaced substantially evenly radially around a portion of the treepod assembly proximate to a bottom portion.
[0054] The tent 1 includes an opening 4 to an internal chamber 5 . The opening 4 may include a closure, such as, by way of non-limiting example, a zipper, which may allow a user of the treepod assembly to selectively reconfigure the opening 4 between an open configuration and a closed figuration to selectively allow or prevent entry into or exit from the tent 1 . One or more windows or vents 6 may also be formed on the tent 1 . A floor of the chamber 5 supports an occupant. In one embodiment, a fabric material of the floor is sufficiently rigid to support the occupant without a frame. For example, in one embodiment, the treepod assembly can support two or three children, or one adult, without a frame.
[0055] The suspension element 2 may comprise a hook or loop of any type with sufficient strength to support the treepod assembly and its occupants from an elevated structure, such as a tree. Although only one suspension element 2 is illustrated, it will be appreciated that the treepod assembly may include any number of suspension elements 2 . For example, the treepod assembly may include two, three, four, or more suspension elements 2 . In one embodiment, the suspension element 2 is interconnected to an upper portion of the treepod assembly. However, the position of the suspension element 2 may be altered.
[0056] The pocket 3 generally comprises a first layer of material 7 and a second layer of material 8 . The second layer 8 is interconnected to the first layer 7 such that when the treepod assembly is suspended above the ground, the second layer 8 drapes freely away from the first layer 7 and the tent 1 . Air enters the pocket 3 through apertures 9 . In this manner, the pocket 3 is at least partially inflated when the treepod assembly is suspended above the ground. The apertures 9 are sized to allow air to enter the pocket 3 without obstruction. However, if the treepod assembly falls to the ground, the apertures 9 restrict the flow of air from the pocket 3 . In this manner, the pocket 3 protects occupants of the treepod assembly from impact with the ground. Said another way, the pocket 3 reduces the peak deceleration of the treepod assembly upon falling to the ground by extending the duration of the deceleration. In one embodiment, the apertures 9 are formed in the second layer 8 . Additionally or alternatively, apertures 9 may be formed in the first layer 7 .
[0057] The apertures 9 may further be adapted, or arranged, to decrease, or prevent, the flow of air from the pocket 3 . In one embodiment, the apertures 9 are positioned on an upper portion of the pocket 3 and within the chamber 5 of the tent 1 .
[0058] In one embodiment, the apertures 9 are generally circular. However, the apertures 9 may be of any size or shape. Further, although the apertures 9 are illustrated substantially evenly spaced axially on the second layer 8 , the apertures 9 may have an irregular spacing and may be positioned in different portions of both the second layer 8 and the first layer 7 .
[0059] The first layer 7 and the second layer 8 may be formed of any material known to those of skill in the art. In one embodiment, the first and second layers 7 , 8 are made of the same material.
[0060] Apertures 9 may be positioned within the chamber 5 through the floor of the tent 1 . In one embodiment, the aperture 9 has a generally triangular shape. However, other shapes of the aperture 9 are contemplated. Aperture 9 also may, but need not, comprise a screen, flap, cover, or other equivalent feature that allows air to freely enter the pocket but restricts airflow out of the pocket to dampen the forces felt by the treepod assembly and its occupants if the suspension of the treepod assembly above the ground fails or the treepod assembly otherwise drops to the ground.
[0061] The treepod assembly may further include a frame. The frame may generally comprise a rigid assembly interconnected to flexible support elements (not marked). The rigid assembly may be interconnected to the suspension element 2 by the flexible elements. The rigid assembly may be generally horizontal and the suspension elements may be generally vertical.
[0062] Any suitable material may be used to form the rigid assembly. In one embodiment, the rigid assembly comprises aluminum. In another embodiment, the rigid assembly is formed of a lightweight metal or alloy. In still another embodiment, the rigid assembly is formed of a plastic material. Additionally or alternatively, the assembly may include a stretchable cord, such as a shock cord.
[0063] The flexible support elements may be formed of any suitable wire or cord. In one embodiment, the flexible support elements have an elastic elongation that is relatively low. In another embodiment, the flexible support elements are formed of a high modulus polyethylene (HMPE). In one embodiment, the flexible elements comprise AmSteel® or AmSteel-Blue®. In another embodiment, the flexible elements are formed of an ultra-high molecular weight polyethylene (UHMWPE) material such as, but not limited, to Dyneema®.
[0064] In one embodiment, the rigid assembly comprises a lower assembly spaced from an upper assembly. The lower assembly may have at least one of a length and a width that is larger than a corresponding length and width of the upper assembly. The lower and upper assemblies may be generally planar.
[0065] Referring now to FIGS. 8 and 9 , a first embodiment of a lower assembly is illustrated. The lower assembly is generally rectangular. As illustrated in the exploded view of FIG. 8B , the lower assembly comprises rods 10 a,b interconnected together by connectors 11 . The lower assembly may have any desired length and width. In one embodiment, the length is between about 6 feet and about 10 feet and the width is between about 3 feet and about 6 feet. Optionally, at least some of the rods 10 b may have an arcuate shape to provide a depression in a medial portion of the assembly. Accordingly, the assembly may have a height of between about 1 inch and about 8 inches. In a preferred embodiment, the height of the assembly is about 5.6 inches. In another embodiment, the first embodiment of the lower assembly has a size sufficient to hold two adult men.
[0066] The first embodiment of the lower assembly may be used with the embodiments of the treepod assembly illustrated in FIGS. 1-7 . Optionally, a treepod assembly may include the lower assembly, a pocket 3 , and a suspension element 2 without a tent 1 . Accordingly, the lower assembly may form a platform positioned above the pocket 3 . After the treepod assembly is suspended above the ground, a tent 1 or structure of any type may subsequently be placed on the platform.
[0067] Referring now to FIGS. 10 and 11 , a second embodiment of a lower assembly is illustrated. The second embodiment of the assembly may be the same as, or similar to, the first embodiment. Accordingly, the second embodiment of the assembly may be formed of the same or similar rods 10 a,b and connectors 11 as the first embodiment. In one embodiment, the second embodiment of the assembly has at least one of a different length and a different width from the first embodiment. The second embodiment of the lower assembly may have a size sufficient to hold two to four adult men. Accordingly, the second embodiment may have a length of between about 6 feet and about 12 feet and a width of between about 5 feet and about 9 feet. As illustrated in FIGS. 11A and 11B , the length may be about 3.025 meters, or about 9.9 feet, and the width may be about 2.20 meters, or about 7.2 feet. In one embodiment, the assembly has a height of less than about 6 inches, particularly about 144.3 millimeters, as illustrated in FIG. 13C . Additionally or alternatively, the second embodiment of the lower assembly may include a greater number of rods 10 a,b and connectors 11 than the first embodiment of the assembly.
[0068] Similar to the first embodiment, the second embodiment of the lower assembly may be used with the embodiments of the treepod assembly illustrated in FIGS. 1-7 . In one embodiment, a treepod assembly may comprise the second lower assembly, a pocket 3 , and a suspension element 2 without a tent 1 .
[0069] The rods 10 a,b and connectors 11 of the lower assemblies of all embodiments of the present disclosure may be comprised of any suitably strong and substantially rigid material. In one embodiment, the rods 10 a,b are formed of aluminum. In one embodiment, the connectors 11 are formed of aluminum. In another embodiment, the connectors 11 are formed of plastic.
[0070] Referring now to FIGS. 12-18 , another treepod assembly of an embodiment of the present invention is illustrated. The treepod assembly illustrated in FIGS. 12-18 differs from the treepod assembly illustrated in FIGS. 1-7 in that it has an approximately rectangular, rather than round, footprint. The treepod assembly illustrated in FIGS. 12-18 may also be larger than the treepod assembly illustrated in FIGS. 1-7 , and may be able to securely accommodate a total weight of at least about 500 pounds while suspended above the ground.
[0071] The treepod assembly illustrated in FIGS. 12-18 generally comprises a tent 1 and a suspension element 2 . Although not illustrated, the treepod assembly may also include attachment points for interconnection of stability lines. The attachment points may comprise hooks. Additionally or alternatively, the attachment points may comprise loops of fabric or cord. In one embodiment, the treepod assembly includes at least three attachment points spaced radially around a portion of the treepod assembly, proximate to a bottom portion.
[0072] The tent 1 includes at least one opening 4 to an internal chamber (not marked). The opening(s) 4 may include a closure, such as, by way of non-limiting example, a zipper, which may allow a user of the treepod assembly to selectively reconfigure the opening(s) 4 between an open configuration and a closed configuration to selectively allow or prevent entry into or exit from the tent 1 . One or more windows or vents 6 may also be formed on the tent 1 ; in the embodiment illustrated in FIGS. 12-18 , the tent comprises a window 6 a and a vent 6 b on each of the left side and the right side. In this embodiment, windows 6 a and vents 6 b differ in that the windows 6 a are larger and more easily accessible to enable a user to view the external environment while keeping opening(s) 4 closed, while vents 6 b are smaller, located higher up on the left and right faces of the tent, and provided primarily for the purpose of enabling air flow between the internal chamber and the external environment. Vents 6 b may optionally be partially covered by a vent cover 12 to allow air to circulate between the internal chamber and the external environment but prevent rain or small debris from entering the internal chamber. As illustrated in FIGS. 12-18 , the windows 6 a and/or vents 6 b may be substantially semicircular, and may be disposed on all or less than all of the external faces of the tent 1 ; by way of non-limiting example, windows 6 a and vents 6 b may be disposed on only the lateral, i.e. left and right, faces of the tent 1 , but any combination of windows 6 a and vents 6 b on none, all, or any combination of faces of the tent 1 is within the scope of the present invention.
[0073] The treepod assembly illustrated in FIGS. 12-18 further comprises a rigid rectangular frame 13 . The frame 13 and the floor of the internal chamber are made of appropriate materials and configured to support one or more occupants, and optionally other items such as camping or hiking equipment. The frame 13 may be interconnected to flexible support elements (not marked) of the tent 1 .
[0074] Any suitable material may be used to form the frame 13 . In embodiments, the frame 13 may comprise, by way of non-limiting example, aluminum, a lightweight metal or alloy, or a plastic material. Additionally or alternatively, the frame 13 may include a stretchable cord, such as a shock cord.
[0075] Although not shown in FIGS. 12-18 , the treepod assembly may comprise one or more flexible support elements. In one embodiment, a flexible support element is comprised of a flap attached at a lower surface to the floor of the assembly, and further comprising a strap, wire, cable or cord on the upper surface of the flap. In this embodiment, the strap or equivalent may further be attached to the suspension element, and either tightened or loosened via a buckle, latch, etc. Thus, the user may adjust the tension between the suspension element 2 and the flexible support element(s) to account for load bearing, sag, etc. Flexible support elements of the tent 1 may be formed of any suitable strap, wire, cable or cord. In embodiments, the flexible support elements may have an elastic elongation that is relatively low, and/or may comprise, by way of non-limiting example, one or more of an HMPE, AmSteel®, AmSteel-Blue®, and a UHMWPE such as Dyneema®.
[0076] The suspension element 2 may comprise a hook or loop of any type with sufficient strength to support the treepod assembly and its occupants from an elevated structure, such as a tree. Although only one suspension element 2 is illustrated, it will be appreciated that the treepod assembly may include any number of suspension elements 2 . For example, the treepod assembly may include two, three, four, or more suspension elements 2 . In the treepod assembly illustrated in FIGS. 12-18 , the suspension element 2 is disposed atop the treepod assembly, but the suspension element(s) 2 may be disposed on any suitable external surface of the treepod assembly. In a preferred embodiment, suspension element(s) 2 and frame 13 of the treepod assembly are capable of securely supporting a weight of at least about 500 pounds.
[0077] It will be understood by those skilled in the art that a treepod assembly according to the present invention may have any combination of features of the embodiments disclosed in the foregoing description or illustrated in the drawings. By way of non-limiting example, a treepod assembly according to the present invention may have a pocket 3 as illustrated in FIGS. 1-7 , or a frame 13 as illustrated in FIGS. 12-18 , or both. Those skilled in the art will understand how to choose an appropriate combination of features for a particular application, and all such combinations are contemplated by the present invention.
[0078] The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the treepod assembly to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments described and shown in the figures were chosen and described in order to best explain the principles of the disclosure, the practical application, and to enable those of ordinary skill in the art to understand the disclosure. | The invention provides means, methods, and devices for suspending persons and goods above the ground while outdoors. Particularly, the invention provides a treepod assembly having a tent and a suspension element, capable of securely supporting at least one occupant while suspended above the ground from a tree or other elevated structure. In some embodiments, the treepod assembly may further include a rigid frame for additional support. Certain embodiments include an inflatable pocket that protects occupants and items inside the tent from injury or damage in case of a fall and impact with the ground. | 4 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims the benefit of and priority on German Patent Application No. 10 2014 017 477.8 having a filing date of 26 Nov. 2014.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention relates to a method for feeding items of laundry to a mangle or to some other laundry-treatment arrangement, wherein an item of laundry is gripped, said item of laundry is spread out at two adjacent corners of a front edge and deposited with said front edge on a feed conveyor which transports the item of laundry to the mangle or to some other laundry-treatment arrangement, and to a method for feeding items of laundry to a mangle or to some other laundry-treatment arrangement, wherein an item of laundry is gripped and said item of laundry is spread out at two adjacent corners of a front edge and transported with this front edge as the leading edge to the laundry-treatment arrangement.
[0004] Furthermore, the invention relates to an apparatus for feeding items of laundry to a mangle or some other laundry-treatment arrangement with a transport system having moveable clamps for holding a respective corner of an item of laundry, to an apparatus for feeding items of laundry to a laundry-treatment arrangement in which the transport system is assigned at least one pair of rollers for the passage of at least one part of an item of laundry and that the two rollers of the pair of rollers can rotate about parallel, upright axes of rotation, and to an apparatus for feeding items of laundry to a laundry-treatment arrangement in which the transport system is assigned at least one pair of rollers for the passage of at least one part of an item of laundry and that the two rollers of the pair of rollers can rotate about parallel axes of rotation that can be brought at least into a nearly upright position.
[0005] 2. Prior Art
[0006] After being washed and dried, items of laundry are ironed in a mangle as so-called dry laundry, where they are freed of residual moisture or immediately folded in a folding device. The items of laundry must be fed to the mangle, folding device or some other laundry-treatment arrangement in a spread-out state. This is carried out mechanically by means of input machines. Said input machines are equipped with a feed conveyor, which feeds the spread-out item of laundry lying on it into the mangle or some other laundry-treatment arrangement.
[0007] The items of laundry are fed into the input machine individually, for example by being placed on the feed conveyor or hung on spreading clamps which spread out the item of laundry in front of the feed conveyor and deposit it on the latter. The hanging of the individual items of laundry on the clamps of the input machine as well as the direct placement of each individual item of laundry on the feed conveyor has been hitherto carried out manually. This is costly in terms of time and personnel. Attempts have been made to automate these activities. They have mostly failed due to the difficulty of automatically locating and gripping adjacent edges of a front edge of items of laundry in a reliable manner with a reasonable expenditure of mechanical investment.
BRIEF SUMMARY OF THE INVENTION
[0008] The object of the invention is therefore to provide a method and apparatus by means of which items of laundry can be fed automatically to a mangle, folding machine or some other laundry-treatment arrangement in a simple and reliable manner.
[0009] A method for achieving the object stated at the beginning is a method for feeding items of laundry to a mangle or to some other laundry-treatment arrangement, wherein an item of laundry is gripped, said item of laundry is spread out at two adjacent corners of a front edge and deposited with said front edge on a feed conveyor which transports the item of laundry to the mangle or to some other laundry-treatment arrangement, characterized in that a surface profile of at least one item of laundry is recorded, from which a location to be gripped on the item of laundry is determined and the item of laundry is then gripped at this location. Accordingly, provision is made to record a surface profile of the respective item of laundry or a plurality of said items of a pile of laundry to be fed. On the basis of the preferably three-dimensional surface profile, it is possible to determine or select, in particular by means of image analysis, an intended or easily accessible location on the respective item of laundry to be fed to the laundry-treatment arrangement and/or to determine the position of this location. The item of laundry can then be securely gripped at this location automatically.
[0010] It is preferably provided that a multidimensional, if appropriate a three-dimensional, image is generated by imaging processes or devices. By virtue of an appropriate, preferably electronic image analysis, it is possible to determine the intended or most easily accessible location on the item of laundry, for example the coordinates of such a location, which can then be approached by an appropriate lifting or gripping means, for example a clamp, a gripper or a suction device, which then grip the item of laundry at the intended location or at the location that has been determined to be the preferred one. Thus, the intended or most favorable location for gripping the respective item of laundry can be determined automatically and subsequently this location can also be approached automatically by the appropriate means and automatically gripped. This thereby eliminates the hitherto manual work steps required to feed items of laundry to a laundry-treatment arrangement.
[0011] The surface profile of each item of laundry, or also of a plurality of items of laundry lying or jumbled in a pile, is preferably determined by three-dimensional imaging means, for example by at least one 3D camera or a laser scanner. This results in a three-dimensional image of the respective item of laundry. Through image analysis, in particular by electronic and/or computational means, it is possible to determine the coordinates of the searched location, preferably a corner, or the particularly favorable location for gripping the item of laundry. By approaching in a targeted manner the location or corner thus determined, the appropriate lifting or gripping means can reliably grip the item of laundry where it can be gripped most conveniently and/or where it is intended to be gripped.
[0012] If an arbitrary location on the item of laundry is to be gripped, this is carried out in that, based on the determined surface profile, in particular a three-dimensional surface profile, which represents a kind of topography, the location having the largest curvature gradient is gripped. At this location one part, so to speak, of the irregularly lying or arbitrarily oriented item of laundry sticks out or projects from a pile containing a plurality of items of laundry. The item of laundry can then be reliably and fully-automatically grabbed at this location by mechanical means.
[0013] It is additionally preferred that the item of laundry be gripped at such a corner which has been identified to be the most accessible for a gripper or some other gripping means on the basis of the evaluation of the determined, preferably three-dimensional surface profile. The determination of the surface profile therefore not only identifies at least one corner of the item of laundry but also establishes which corner of the item that can be best gripped.
[0014] A preferred option for the further design or development of the method provides that, alternatively or in addition, the surface profile of an item of laundry hanging from a fastening means of the apparatus is determined and, based on this surface profile, the item of laundry is gripped at another free corner in a targeted manner, for example by means of another fastening means. This therefore results in the automatic gripping of two locations, and if required at two corners of the item of laundry.
[0015] It is also conceivable, by means of the recorded surface profile of an item of laundry hanging by a corner from a fastening means, to locate the corner adjacent to this corner and to grip it in a targeted manner. This makes it easily possible to grip an item of laundry automatically at adjacent corners of an edge, this edge preferably being a leading front edge with which the item of laundry is fed to the laundry-treatment arrangement.
[0016] One preferred design of the method provides that, on the basis of the determined surface profile or topography of the item of laundry, it is possible to identify the orientation of the hem of said item of laundry. It is thereby possible to establish on which side of the item of laundry a narrow, marginal strip, which is folded over during the formation of the hem in the item of laundry, is located. On the basis of the location of the hem as known from the evaluation of the determined surface profile, it is possible to feed the item of laundry to the laundry-treatment arrangement, in particular to place it on a feed conveyor, in such an orientation that the hem purposefully lies facing up or down, thereby assuming the intended position or orientation. This orientation of the hem during manual feeding of the laundry-treatment arrangement or input machine used to be performed by a human operator. That could lead to faulty feeding inputs. Due to the invention's automated method, such faulty feed inputs are no longer possible.
[0017] A further method for achieving the object set forth at the beginning, whereby this can also be a preferred further development of the previously described method, is a method for feeding items of laundry to a mangle or to some other laundry-treatment arrangement, wherein an item of laundry is gripped and said item of laundry is spread out at two adjacent corners of a front edge and transported with this front edge as the leading edge to the laundry-treatment arrangement, characterized in that, in the case of an item of laundry hanging down from a held corner, a lowest corner of said item of laundry is gripped and stretched, whereby the other corners of the item of laundry are formed such that they assume positions that can be gripped. Accordingly, provision is made that, in the case of an item of laundry held at one corner, the lowest point of the item of laundry hanging down by a corner is gripped and the item of laundry is then stretched, in particular only lightly stretched, as these corners are moved apart. This causes the remaining corners of the item of laundry to be configured such that they assume a position which can be gripped and/or which is suitable for image acquisition. The item of laundry can then be automatically gripped also at such a corner formed in this manner, after which the item of laundry is held at the targeted corners, preferably adjacent corners of a front edge.
[0018] It can be advantageous to design the method such that the item of laundry held at diagonally opposite corners is stretched. This then forms two free corners that are adjacent to each of the held corners. This makes it easily possible to determine automatically the adjacent corners of the item of laundry and subsequently to grip them mechanically in a targeted manner.
[0019] Another possibility offered by the advantageous further development of the method provides for the automatic determination, preferably by means an imaging process, of the position of the free corners formed during the stretching of the item of laundry at preferably diagonally opposite corners when the surface profile is determined. In this manner, the positions of the free corners formed during the stretching action can be calculated from the evaluation of the recorded image of the laundry item, if possible also as a three-dimensional image, thereby providing the spatial positions of the free corners formed by the stretching of the item of laundry, in particular their coordinates. From this it can also be established which of the free corners, adjacent to a particular held corner of the item of laundry, delimit a short or a long edge of the item of laundry. The item of laundry can then be gripped automatically in the way that it should be transferred to the following laundry-treatment arrangement, for example in the feed conveyor of a input device upstream of a mangle.
[0020] An apparatus for achieving the object set forth at the beginning is an apparatus for feeding items of laundry to a mangle or some other laundry-treatment arrangement with a transport system having moveable clamps for holding a respective corner of an item of laundry, characterized in that the transport system is assigned at least one imaging device for the purpose of generating a surface profile of an item of laundry. This apparatus is provided with an image-generating device in the course of the transport system for feeding single items of laundry to a laundry-treatment arrangement, in particular to a mangle or an input machine upstream thereof. It is therefore possible to record at least one surface profile of the item of laundry before the transport system and/or during its course, whereupon the item of laundry can be securely gripped. It is thereby possible to grip an arbitrary location on the item of laundry, but also a specific location, such as a corner.
[0021] As an alternative or in addition, image-generating devices can be provided at various positions along the course of the transport system which serve to direct differently moveable clamps or other types of gripping means of the transport system toward specific locations, in particular corners, on the item of laundry in a targeted manner and to grip them. Such processes as the rehanging of the item of laundry, the changing of clamps, the gripping of specific locations or corners of the item of laundry and/or the reorientation of the item of laundry can thereby be carried out automatically and reliably.
[0022] Individual or a plurality of image-generating devices are preferably located at various points of the transport system. These may be identical image-generating devices, each of which generate three-dimensional images, for example. But it is also conceivable, depending on the purpose of the task at hand, to configure each image-generating device differently. For example, image-generating devices, above all cameras, can be provided which generate three-dimensional images in some cases and two-dimensional images in other cases. It is also conceivable that the image-generating devices at specific points of the conveying section generate a surface profile of only one part of the item of laundry, namely only of that part whose position, orientation and/or configuration must be recorded in order to manipulate this part in the appropriate manner, in particular to grasp it.
[0023] A further apparatus for achieving the object set forth at the beginning, which can also be a preferred further development of the previously described apparatus, is an apparatus for feeding items of laundry to a laundry-treatment arrangement, characterized in that the transport system is assigned at least one pair of rollers for the passage of at least one part of an item of laundry and that the two rollers of the pair of rollers can rotate about parallel, upright axes of rotation. Accordingly, the transport system is assigned at least one pair of rollers for the passage of at least one part of an item of laundry between them, wherein the rollers of the pair of rollers can rotate about parallel upright axes of rotation. The axes of rotation can preferably run vertically, but can also run at a slight oblique angle to the vertical. The rollers form a gap resulting in the mechanical locating of a particular position, in particular of a corner, of the item of laundry drawn through the gap between the parallel rollers. The vertical or practically vertical orientation of the parallel axes of rotation of the two adjacent rollers facilitates the finding of the corner and the receiving of a section of the item of laundry that is moved past the rollers of the transport system. This part of the item of laundry, usually a rear part, thus unavoidably comes between the rollers with its most outer corner and can thus be reliably detected. This also applies when a clamp of the transport system grips a plurality of items of laundry at the same time. Then only a rear corner of an item of laundry is formed between the upright pair of rollers.
[0024] A preferred further development of the apparatus provides that the axes of rotation of the roller pair can be pivoted synchronously while maintaining their parallel alignment. Preferably the axes of rotation of the pair of rollers can be pivoted from an upright, i.e. vertical or nearly vertical alignment, to a horizontal or nearly horizontal alignment (and back). As a result, a part of the item of laundry can reliably pass between the initially upright rollers of the pair of rollers and, following the pivoting of the pair of rollers, the corner is aligned for easy gripping.
[0025] One advantageous arrangement of the apparatus provides that the rollers of the pair of rollers can be driven preferably to rotate in opposite directions, specifically and in particular at the same rotational speed. By stopping the drive, the found corner of the item of laundry can be held temporarily in a clamp-like manner until it is received by a clamp or some other retaining means, including, for example, a suction device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Preferred exemplary embodiments of the invention are described in more detail in the following as based on the drawings where:
[0027] FIG. 1 shows a schematic representation of items of laundry being fed to a laundry-treatment arrangement,
[0028] FIG. 2 shows a schematic representation analogous to FIG. 1 of a second exemplary embodiment of the invention, and
[0029] FIG. 3 shows a schematic representation analogous to FIGS. 1 and 2 of a third exemplary embodiment of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] The figures schematically illustrate different approaches for the automatic feeding of items of laundry to a laundry-treatment arrangement. For the purposes of the following description, it will be assumed that the laundry-treatment arrangement (not shown) is an input machine for feeding preferably spread-out items of laundry to a mangle. However, the invention is not limited to this.
[0031] A single, washed and at least partially dry item 10 of laundry that is not spread out and is arbitrarily oriented, for example in a jumbled fashion, or also a pile of washed and at least partially dried items 10 of laundry are transported to a receiving position 12 by means of a schematically represented conveyor 11 or other transport means. From this receiving position 12 a item 10 of laundry is in each case fed to the input machine (not shown) in a fully automated fashion with no accompanying manual assistance, preferably deposited on a feed conveyor of the input machine with at least a partially spread-out front edge 13 , or transferred to the input machine on clamps, in particular spreading clamps.
[0032] Shown in FIG. 1 is a single item 10 of laundry situated in arbitrary orientation on the conveyor 11 of the receiving position 12 . At the receiving position 12 an image is generated of the item 10 of laundry of irregular orientation by means of at least one shown camera 14 . This is preferably a three-dimensional image. This image of the surface profile represents at least one part of a topography of the item 10 of laundry. In FIG. 1 only a single camera 14 is shown symbolically in the region of the receiving position 12 . This may be a 3D camera or a laser scanner. But it is also conceivable to provide a plurality of cameras 14 at the receiving position 12 , which are expediently distributed at different positions around the item 10 of laundry at the receiving position 12 .
[0033] The receiving position 12 is assigned a gripping device 15 which in the shown exemplary embodiment has a rail 16 which is inclined obliquely upwards and which has two clamps 17 that can travel upwards along it in linear fashion. The clamps 17 grip alternately an item 10 of laundry at the receiving position 12 . While one clamp 17 is receiving an item 10 of laundry at the receiving position 12 , the other clamp 17 can transfer a previously gripped item 10 of laundry to another conveyor at an opposite and higher end region of the rail 16 . But it is also conceivable that the gripping device 15 has only a single clamp or another type of gripping means, for example a suction device. The gripping device 15 can also be formed from a long-stroke cylinder. In this case, the gripping means 15 has only a single clamp 17 .
[0034] The gripping device 15 is followed by a transport device 18 . The transport device 18 shown here has a straight rail 19 , which runs approximately horizontal in the shown exemplary embodiment. A plurality of preferably identical clamps 20 can travel on the rail 19 in a rectilinear fashion. An upper region of the rail 16 of the gripping device 15 and an end region of the rail 19 directed toward the rail 16 are located at a transfer point 21 in such a tight arrangement that a item 10 of laundry held by the clamp 17 can be received in the upper end region of the rail 16 by a clamp 20 at the end region of the rail 19 of the transport device 18 which points toward the gripping device 15 .
[0035] The transfer point 21 between adjacent end regions of the rails 16 and 19 is also assigned at least one camera 22 . For simpler presentation purposes, only one camera 22 is shown in FIG. 1 , although a plurality of preferably identical cameras 22 can be provided at different positions. The at least one camera 22 can generate an image, preferably a three-dimensional image, of the item 10 of laundry at the transfer point 21 . This image reproduces the surface profile or topography of at least one part of the item 10 of laundry in the region of the transfer point 21 . Accordingly, the clamp 20 of the transport device 18 located in each case at the transfer point 21 can grip an arbitrary corner 23 of the item 10 of laundry.
[0036] The end 24 of the rail 19 of the transport device 18 situated opposite the gripping device 15 (shown to the right in FIG. 1 ) is located at a reorientation point 25 . At this reorientation point 25 the item 10 of laundry held at a corner 23 by the clamp 20 initially hangs down freely. The surface profile or topography of the item 10 of laundry hanging down from the clamp 20 at the reorientation point 25 is in turn determined by at least one camera 22 to generate preferably a three-dimensional image. In the shown exemplary embodiment, two opposite, preferably identical cameras 22 are shown which record the surface profile or topography of the item 10 of laundry from opposite sides of the item 10 of laundry, preferably an outer side and an inner side.
[0037] Provided at the reorientation point 25 is a stretching clamp 26 which is traversable, preferably on a linear track 27 . For example, for this purpose the stretching clamp 26 can be attached to a high-speed servo axis which in the simplest case is formed by a pneumatic cylinder. The stretching clamp 26 grips a corner 28 at the lowest point of the item 10 of laundry hanging down from the clamp 20 . This lower corner 28 lies diagonally opposite the top corner held by the clamp 20 .
[0038] Due to the stretching clamp 26 being moved in the feed direction 29 toward the input machine (not shown) while the clamp 20 remains stationary, the item 10 of laundry is at least somewhat or partially stretched, thus forming a diagonal fold 30 between the diagonally opposite corners 23 and 28 . In the process, the remaining corners 31 , 32 of the item 10 of laundry are formed, with the result that the image recorded by the cameras 23 , which corresponds to the three-dimensional surface profile of the item 10 of laundry, can provide reliable detection or identification of the corners 31 and 32 .
[0039] Provided at the reorientation point 25 below the item 10 of laundry is a pair of clamps comprising clamps 33 , 34 that can moved toward and apart from each other. The clamps 33 , 34 can be moved toward and apart from each other by means of appropriate linear drives. The clamps 33 and 34 are moved apart to the extent that they attain a distance from one another that allows them to still grip the corner 28 held by the clamp 26 and a corner 32 that has become free during the stretching of the item 10 of laundry. The clamps 33 , 34 of the pair of clamps thereby hold two adjacent corners 28 and 32 of an edge of the item of laundry, which can possibly be the front edge 13 .
[0040] In the shown exemplary embodiment, a second pair of clamps having the clamps 35 , 36 is provided above the pair of clamps with the clamps 33 , 34 . The clamps 35 , 36 can also be moved together and apart independently of each other, but can also be moved together along a preferably a straight conveying section 37 in the feed direction 29 while maintaining the same distance from one another. The clamps 35 , 36 take the item 10 of laundry from the clamps 33 , 34 , specifically also at the corners 28 and 32 . The item 10 of laundry is then held at opposite corners 28 and 32 of the front edge 13 in a spread-out or partially spread-out position, i.e. in a preliminary spread-out position. The item 10 of laundry thereby hangs down from the clamps 35 and 36 and can be transported along the conveying section 37 to the input machine (not shown).
[0041] It is conceivable that the pair of clamps comprising the clamps 35 , 36 or the pair of clamps comprising the clamps 33 , 34 can be omitted. In that case, no transfer from one pair of clamps to the other occurs at the reorientation point. Instead, the item 10 of laundry held on the corners 28 and 32 is directly transported to the input machine in the feed direction 29 by the clamps 33 , 34 or 35 , 36 .
[0042] The method according to the invention is implemented by the previously described apparatus as shown in FIG. 1 as follows:
[0043] Either a single item 10 of laundry or a pile of a plurality of items 10 of laundry is transported by the conveyor 11 to the receiving position 12 . At the receiving position 12 a plurality of items 10 of laundry are immediately separated out in the process. Even when only a single item 10 of laundry is transported to the receiving position 12 , this item is disordered, in particular crumpled. For that reason, at least one camera 14 at the receiving position 12 records preferably a three-dimensional image of the surface profile or topography of the item 10 of laundry. This results in a three-dimensional image of the structure or topography of the item 10 of laundry lying on the conveyor 11 . The three-dimensional image of the at least one item 10 of laundry at the receiving position 12 is preferably electronically processed and evaluated by image processing. Above all, a determination is made as to which location on the item 10 of laundry on the conveyor 11 can best be gripped. For this purpose, preferably the location of the largest curvature gradient of the item 10 of laundry at the receiving position 12 is determined electronically or computationally, and the coordinates of this location are set. Accordingly, the clamp 17 of the gripping device 15 is moved in a targeted manner toward the location that can be conveniently gripped and the item 10 of laundry is gripped here.
[0044] The three-dimensional image or surface model of the item 10 of laundry that is recorded by the at least one camera 14 extends in three dimensions or spatial directions, namely in an X, Y and Z direction or axis. This makes it possible to grip any form that the arbitrarily positioned item 10 of laundry assumes. In particular, this makes it possible to determine the heights and recesses of the item 10 of laundry, thereby allowing conclusions to be made concerning the surface profile, in particular the topography, of the item 10 of laundry.
[0045] The at least one camera provides a stereoscopic, three-dimensional image of the topography or surface profile of the item 10 of laundry. This is particularly the case when the item 10 of laundry is viewed by a plurality of cameras 14 placed at various viewing angles. By means of the special imaging of the item 10 of laundry using two cameras 14 or more than two cameras 14 set at different viewing angles, it is possible to create a three-dimensional, spatial image and/or surface model in that three-dimensional coordinates are assigned to every point on the surface of the item 10 of laundry. This can be carried out by image processing or further image processing, for example by means of a computer.
[0046] It is sufficient if the at least one camera 14 records an image of the item 10 of laundry or of the pile containing a plurality of items 10 of laundry and this image is analyzed. But it is also conceivable to record images continuously or to record an image at regular intervals, and then to compare these images appropriately.
[0047] After the topography or the surface profile of the item 10 of laundry, of a plurality or, preferably, all of the visible items 10 of laundry in the pile of laundry has been established by electric and/or computational image analysis, it is possible to identify at least one location which is particularly suited for the gripping or separating out of the item 10 of laundry. Such a location is preferably a region where the item 10 of laundry exhibits a large curvature or a large curvature gradient. For example, this can be a fold, a crease, an edge or a corner of the item 10 of laundry. This suitable location is calculated by image analysis of the recorded topography or of the recorded surface profile of the item 10 of laundry using a computer, for example. This can be done such that, for two respectively adjacent points, the angle between two tangents or tangential planes of these points is determined. If this angle is acute or if the tangents do not intersect, one can assume a large curvature or a large curvature gradient. Such a location is then particularly suitable for gripping and/or separating the item 10 of laundry.
[0048] The coordinates of the preferred location on the item 10 of laundry automatically determined by computational image processing are likewise calculated and transferred to the drive, preferably to the high-speed servo axis of the clamp 17 so that the clamp 17 of the gripper can be moved precisely to the calculated, preferred location on the item 10 of laundry. If a plurality of locations on the item 10 of laundry are determined to be suitable for gripping, that location is chosen which can be approached most quickly by the gripper 14 , in particular the one with the shortest travel path.
[0049] In the shown exemplary embodiment, the location that has been derived from the image recorded by the at least one camera 14 represents an arbitrary location on the item 10 of laundry. It is also conceivable that the analysis of the recorded image, in particular of the three-dimensional image, is conducted such that a corner of the item 10 of laundry is identified, with this corner being grasped in a targeted manner by the clamp 17 of the gripping device 15 .
[0050] According to the shown exemplary embodiment, after the clamp 17 of the gripping device 15 has grasped the item 10 of laundry at an arbitrary location that is particularly suited for gripping, it is moved away from the receiving position 12 by means of the clamp 17 moving along the rail 16 and slightly lifted. At the upper end of the rail 16 the item 10 of laundry is recorded by at least one camera 22 , preferably once again as a three-dimensional image. As a result of the appropriate analysis of the surface profile of the item 10 of laundry reproduced in this image, a corner 23 of the item 10 of laundry still hanging on the clamp 17 is identified from the surface profile or topography of the item 10 of laundry as determined by the at least one camera 22 and gripped by a clamp 20 of the transport device 18 . The clamp 17 of the gripping device 15 is subsequently opened so that the item 10 of laundry hangs down by the corner 23 from the clamp 20 .
[0051] Due to the clamp 20 travelling along the rail 19 of the transport device 18 , the item 10 of laundry hanging down from said clamp 20 is moved from the transfer point 21 between the gripping device 15 and the transport device 18 to the reorientation point 25 . Here the lowest point of the item 10 of laundry hanging down from the clamp 20 and the farthest away from the latter is gripped by the stretching clamp 26 . Because the lowest point of the item 10 of laundry is a corner 28 located diagonally opposite to the corner 23 , the stretching clamp 26 necessarily grips the corner 28 of the item 10 of laundry which lies diagonally opposite the upper corner 23 . As a result of the stretching clamp 26 being moved on the track 27 in the feeding direction 29 , the item 10 of laundry is now stretched, preferably only lightly stretched, between the diagonally opposing corners 23 and 28 , with the corners 23 and 28 thereby being drawn apart. Preferably the corners 23 and 28 are drawn apart to the extent that the item 10 of laundry between these corners 23 and 28 is only slightly tautened but not subjected to any appreciable mechanical loads. When the diagonally opposite corners 23 and 28 are drawn apart by the movement of the stretching clamp 26 , the diagonal fold 30 is formed in the item 10 of laundry between these corners 23 and 28 . At the same time, this causes the formation of the other corners 31 and 32 of the item 10 of laundry such that said corners can be clearly registered and imaged by the cameras 22 assigned to the reorientation point 25 .
[0052] By means of an analysis of the image recorded by the cameras 22 or, if applicable, by only one camera 22 of the stretched item 10 of laundry, the positions of the corners 31 and 32 can be determined computationally. Of the corners 31 and 32 thus determined, either a corner 31 or 32 is gripped which can be most easily gripped or, in the case of a rectangular item 10 of laundry, a corner 31 or 32 is gripped which, together with the corner 28 held by the stretching clamp 26 , borders the intended front edge 13 of the item 10 of laundry, namely either a transverse edge or a longitudinal edge.
[0053] As shown in the exemplary embodiment of FIG. 1 , the clamp 34 grips the corner 32 adjacent to the corner 28 which is part of a transverse edge of the item 10 of laundry. In this case, the item 10 of laundry is fed to the input machine, with the shorter transverse edge being its leading front edge 13 , and deposited on the feed conveyor of the input machine. If the item 10 of laundry is to be fed to the input machine with the longer longitudinal edge as its leading edge, the clamp 34 grips the other corner 31 formed when the item 10 of laundry is stretched out.
[0054] The clamps 33 and 34 of the pair of clamps can be purposefully moved along a preferably straight conveying section 38 to the corners 28 and 32 , wherein the movement of the clamp 34 to the corner 32 , which becomes free or is formed when the item of laundry is stretched, is controlled on the basis of a computational analysis of the three-dimensional image of the item of laundry as recorded by the at least one camera 22 at the reorientation point 25 .
[0055] In the shown exemplary embodiment a second pair of clamps is provided as clamps 35 and 36 above the clamps 33 and 34 . The clamps 35 and 36 receive the front edge 13 at its corners 28 and 32 from the clamps 33 and 34 . The item 10 of laundry which subsequently hangs with its corners 32 and 28 under the clamps 35 , 36 is now transported along the conveying section 37 in the feed direction 29 to the input machine and is preferably either deposited directly on the feed conveyor of the input machine or transferred by spreading clamps to the input machine.
[0056] At the reorientation point 25 , the at least one camera 22 is also used to determine, in the case of a hemmed item 10 of laundry, on which side of the item of laundry the narrow marginal strips of the item 10 of laundry which form the hem are located. Particularly in the case of table linen the hem side of the item 10 of laundry, i.e. the side on which the folded-over narrow marginal edge of the item 10 of laundry is located, must be fed into a mangle such that the hem side comes into contact with the mangle roller but not with the ironing surface of the mangle trough when it is standing idle. Because it is possible to determine, using the at least one camera 22 , on which side of the item 10 of laundry viewed by the cameras 22 the hem is located, the item 10 of laundry can be fed to the input machine by the selective feeding to the input machine with the corners 28 and 32 hanging on the clamps 33 , 34 or 35 , 36 in the correct orientation for mangling.
[0057] If only one pair of clamps, either clamps 33 , 34 or clamps 35 , 36 , are provided at the reorientation point 25 , the item 10 of laundry can be also be reoriented, on the basis of the position of the hem as recorded by the at least one camera 22 , by altering the sequence of the clamps 35 , 36 or 33 , 34 by having one clamp overtake the other clamp along the conveying section 37 or 38 , for example.
[0058] FIG. 2 shows an apparatus which essentially corresponds to the previously described apparatus and as such the same designation numbers are used to indicate the same parts of the apparatus. In the apparatus of FIG. 2 a pair of rollers 39 is provided at the transfer point 21 . The pair of rollers 39 has two adjacent, upright rollers 40 , of which only the roller 40 at the front is shown in FIG. 2 . The two identical rollers 40 can rotate about parallel, vertical axes of rotation 41 . Formed between the rollers 40 is a small gap for the passage of at least one part of the item 10 of laundry.
[0059] In the shown exemplary embodiment the parallel uprights rollers 40 can be driven in opposite directions in such a way that they transport the item 10 of laundry or only a part of it through the gap between the adjacent rollers. It is also conceivable that only one of the two parallel rollers 40 is driven, with the second roller 40 rotating freely when an item 10 of laundry is transported between the rollers 40 .
[0060] The item 10 of laundry is dropped by opening the clamp 17 above the rollers 40 , whereby due to the upright arrangement of the rollers 40 the item 10 of laundry enters the gap between the rollers 40 and is transported transversely through the gap. As soon as the item 10 of laundry has been transported almost completely through the gap between the rollers 40 , with only a rear tip or a rear corner, preferably the corner 28 , still hanging in the gap, this is determined by means of an appropriate detection means and correspondingly the clamp 20 of the transport device 18 is controlled such that it grips the item 10 of laundry at its rear tip or the rear corner, specifically either when its outermost corner or outermost tip is still located in the gap between the rollers or immediately after the rearmost tip or rearmost corner of the item 10 of laundry has left the gap between the rollers 40 .
[0061] It is conceivable to arrange the axes of rotation 41 of the two adjacent rollers 40 at a slightly oblique opposing angle to one another such that a downward tapered and slightly V-shaped gap is created between the rollers 40 .
[0062] It is also conceivable that the gap between the rollers 40 is closed at the bottom by a transverse beam under the rollers 40 or by a transversely directed, horizontal roller located in front of or behind the two parallel rollers 40 .
[0063] FIG. 3 shows a modified version of the apparatus shown in FIG. 2 . In this modification the pair of adjacent rollers is pivotable. Specifically, the rollers 40 can be pivoted together about their axes of rotation 41 from an initial position with vertical axes of rotation 41 to a position with approximately horizontal axes of rotation 41 . The rollers 40 are pivoted about a horizontal pivoting axis 42 which runs through the axes of rotation 41 of both rollers 40 and is located at a distance below the rollers 40 . In the shown exemplary embodiment the rollers 40 can be pivoted equally by about 90°.
[0064] In the upward pivoted initial position of the rollers 40 the axes of rotation 41 run vertically, but can also run at a slight oblique angle to the vertical. It is in this initial position of the rollers 40 that an item 10 of laundry is dropped from the clamp 17 over the rollers 40 . The item 10 of laundry thereby enters into the gap between the vertical or nearly vertically oriented rollers 40 . The rollers 40 are subsequently pivoted equally in common about their horizontal pivoting axes 42 by approximately 90° so that the rollers 40 reach a horizontal or nearly horizontal position. In this horizontal position the rollers 40 are driven in opposing directions until a rearmost—and due to the pivoting of the rollers 40 into the horizontal position—upper tip or a corner 23 is still located between the rollers 40 , i.e. with a major portion of the item 10 of laundry having just been transported through the rollers 40 . If appropriate, the drive of the rollers 40 can be stopped. The corner 23 of the item 10 of laundry is thereby purposefully located above the rollers 40 in that the corner 23 projects approximately upwards from the gap between rollers 40 . The item 10 of laundry can then be securely gripped by the clamp 20 of the transport device 18 at this corner 23 and taken away. In the process the item 10 of laundry can be drawn out of the gap between the rollers 40 . It is also conceivable to release the item 10 of laundry by opening the gap between the rollers 40 or to move the item 10 of laundry out of the gap by driving the rollers 40 in opposite directions. This can also be performed in such a manner that the rollers 40 are driven to rotate in opposite directions after the corner 23 of the item 10 of laundry has been gripped by the clamp 20 .
[0065] After the item 10 of laundry has been taken away from the two parallel rollers 40 by means of the transport device 18 and thus freeing up the rollers 40 , the latter are pivoted back into their initial vertical position in order to receive a next item 10 of laundry.
[0066] The automated process of finding the corner using the previously described pair of parallel rollers 40 can also be provided at any other locations of the apparatuses shown and described in exemplary fashion in FIGS. 1 to 3 . It is also conceivable to employ the automated process of finding the corner between two parallel rollers 40 at other sites in the region of the laundry than those shown in FIGS. 1 to 3 .
LIST OF DESIGNATIONS
[0000]
10 laundry article
11 conveyor
12 receiving position
13 front edge
14 camera
15 gripping device
16 rail
17 clamp
18 transport device
19 rail
20 clamp
21 transfer point
22 camera
23 corner
24 end
25 reorientation point
26 stretching clamp
27 track
28 corner
29 feed direction
30 diagonal fold
31 corner
32 corner
33 clamp
34 clamp
35 clamp
36 clamp
37 conveying section
38 conveying section
39 pair of rollers
40 rollers
41 axis of rotation
42 pivot axis | Items of laundry are fed from an input machine to a mangle or some other laundry-treatment arrangement. Operating personnel are employed to feed the input machine with the items of laundry. This is costly in terms of time and personnel. The invention makes provision for determining surface profiles of the items of laundry by means of imaging installations. From these surface profiles a location for the automatic gripping of the item of laundry or of a corner of same, and preferably also the position of the location or corner, is determined by electronic image processing, whereby the location or corner of the item of laundry can be securely gripped in an automatic and targeted manner. By virtue of the described measures, hitherto manual activities in front of the input machine can be easily performed in a reliable and fully-automatic mode. | 3 |
BACKGROUND
[0001] Within the field of computing, many scenarios involve a collection of facts about an individual (e.g., directly received from the individual; observed about the individual; and/or based on an inference about the individual), where such facts are stored in an individual profile and used to personalize one or more services based on the details of the service. For example, a retail service may recommend products to an individual based on the individual's previous purchases, and a social network may present advertisements to the individual that are based on facts specified in the social profile of the individual.
[0002] Many such individual profiles may be informed by inferences about the individual, based on the contents of expressions authored by the individual and/or activities performed by the individual. For example, if an individual frequently expresses an interest in a particular type of food, or frequently visits restaurants that offer a particular type of food, an inference may be made that the individual enjoys the particular type of food, even if the individual has not expressly indicated such enjoyment in the individual profile.
SUMMARY
[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key factors or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0004] Inferences about an individual may be formulated with an inference confidence that relates to the accuracy of the inference as a fact describing the individual. For example, if an individual consumes a particular type of food on a daily basis, an inference may be drawn about the individual's food preferences than if the individual only consumes the particular type of food once per month. Accordingly, the consideration of the inference confidence of the inferences while generating the individual profile through inferences (e.g., only adding inferences to the individual profile if the inference confidence in the accuracy or strength of the inference exceeds a desired threshold) may enable the formulation of a more accurate individual profile.
[0005] However, the aggregation of the individual profile based on inferences may result in a large collection of facts about the individual, which may not be significantly representative of the individual's identity. Rather, such an individual profile may include a large number of facts that, even if derived from inferences having a high inference confidence and therefore accurate about the individual, are not regarded by the individual as representing his or her particular identity. As a first such example, the individual profile may include a fact that describes the individual, but also a large number of other individuals in the individual's community, and that is therefore not distinctive of the individual; e.g., a fact that the individual enjoys ice cream may also describe everyone the individual knows enjoys ice cream, the inclusion of this fact in the individual's profile may not distinguish the individual's identity. As a second such example, the individual profile may include a fact that is only incidental to the individual's identity; e.g., the individual may visit the same restaurant every day for lunch more due to convenience than personal preference, and the individual may not consider the restaurant or food type as part of his or her identity. Indeed, the individual may not even particularly enjoy the food type at the restaurant, so even though the inference confidence in the fact that the individual frequently visits the restaurant offering the associated food type is accurate, the inferred fact that the individual enjoys the associated food type As a third such example, the individual profile may include a fact that the individual considers private; e.g., the individual may enjoy a particular music group that is associated with a negative social stigma, and may not desire this inference to be added to the individual profile.
[0006] In each of these scenarios, even if the inference exhibits a high inference confidence that the inference accurately describes the individual, the inferred fact may significantly reflect the identity of the individual. An individual profile populated with such inferred facts may therefore not adequately describe the individual.
[0007] In view of these considerations, presented herein are techniques for generating an individual profile of an individual. Upon receiving a fact about the individual at a detection time, an embodiment may determine a significance of the fact to the identity of the individual. Upon determining that the significance of the fact to the identity of the individual exceeds a significance threshold, the embodiment may add the fact to the individual profile; and upon failing to add the fact to the individual profile within an evaluation duration of the detection time, discard the fact about the individual. By evaluating the significance of each fact to the identity of the individual, and adding to the individual profile only the facts that exceed the significance threshold, the generation of the individual profile may be achieved that is more descriptive of the individual's identity than an individual profile that is simply populated with facts having a high inference confidence.
[0008] To the accomplishment of the foregoing and related ends, the following description and annexed drawings set forth certain illustrative aspects and implementations. These are indicative of but a few of the various ways in which one or more aspects may be employed. Other aspects, advantages, and novel features of the disclosure will become apparent from the following detailed description when considered in conjunction with the annexed drawings.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an illustration of an example scenario featuring the generation of an individual profile using a set of inferences.
[0010] FIG. 2 is an illustration of an example scenario featuring the generation of an individual profile according to the significance of the respective facts to the identity of the individual, in accordance with the techniques presented herein.
[0011] FIG. 3 is a flow diagram of an example method of configuring a device to generate an individual profile in accordance with the techniques presented herein.
[0012] FIG. 4 is a component block diagram of an example system provided to configure a device to generate an individual profile in accordance with the techniques presented herein.
[0013] FIG. 5 is an illustration of an example computer-readable medium comprising processor-executable instructions configured to embody one or more of the provisions set forth herein.
[0014] FIG. 6 is an illustration of an example scenario featuring an evaluation of the significance of the fact based on the frequencies of the individual's expressions and activities in accordance with the techniques presented herein.
[0015] FIG. 7 is an illustration of an example scenario featuring an individual profile manager that evaluates the significance of the respective facts and the individual sensitivity of the individual in accordance with the techniques presented herein.
[0016] FIG. 8 is an illustration of example scenario featuring a determination of the significance of respective facts to the individual profile of the individual in accordance with the techniques presented herein.
[0017] FIG. 9 is an illustration of an example scenario featuring continued monitoring of the significance of a fact to the individual profile of an individual in accordance with the techniques presented herein.
[0018] FIG. 10 is an illustration of an example computing environment wherein one or more of the provisions set forth herein may be implemented.
DETAILED DESCRIPTION
[0019] The claimed subject matter is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to facilitate describing the claimed subject matter.
A. Introduction
[0020] FIG. 1 presents an illustration of an example scenario 100 featuring a technique for generating an individual profile 110 of an individual 102 . In this example scenario 100 , at a first time 120 , various inferences about the individual 102 may be formulated in order to identify facts 112 to be added to the individual profile 110 . As a first such example, the individual 102 may be associated with a profession 104 , such as a teacher; a location 106 where the individual 102 lives, such as New York; and an interest 108 that the individual 102 holds, such as an appreciation of the sport of baseball. Such inferences may be determined with varying degrees of inference confidence, such as the duration of the individual's tenure as a teacher; the amount of time that the individual 102 spends in New York; and the number of baseball games that the individual 102 attends. The inference confidence may be used to determine whether respective inferences accurately reflect facts 112 about the individual 102 ; e.g., if the individual 102 only resides in New York a few days per year, the inference confidence may be very low, but if the individual 102 resides in New York every day, the inference confidence may be very high. An embodiment may add facts 112 to the individual profile 110 only for inferences having an inference confidence that exceeds an inference confidence threshold, indicating the reliability that the associated fact 112 is true about the individual 102 . Moreover, an embodiment may update the facts 112 of the individual profile as the inference confidence changes. At a second time 112 , if the individual 102 updates his or her mailing address from New York to Chicago, the fact 112 in the individual profile 110 indicating the individual's location 106 may be updated. Additionally, the activities 116 in which the individual 102 frequently engages may be evaluated to adjust the inference confidence; e.g., detecting that the individual 102 is engaging in activity 116 such as watching a game of soccer may enable an inference 118 that the individual 102 harbors an interest 108 in soccer, and if the inference confidence of the inference 118 is sufficiently strong, the interest 108 may be added as a fact 112 to the individual profile 110 of the individual 102 .
[0021] While inference-based techniques may be used to generate an individual profile 110 of an individual 102 , such techniques based primarily upon inference confidence may result in the generation of an individual profile 110 that does not appropriately reflect the identity of the individual 102 . In a variety of ways, the addition of inferences 118 to the individual profile 110 as facts 112 about the individual 102 may not reflect the traits about the individual considers significant about his or her identity.
[0022] As a first such example, an individual 102 may exhibit a profession 104 of a teacher. However, a first individual 102 consider such a profession 104 to be an integral component of his or her identity, while a second individual 102 may regard such a profession 104 only as a job or pastime. Notably, the variable attitude of such individuals 102 may be unrelated to the inference confidence that the inferences; i.e., the fact 112 that each individual 102 is a teacher may be entirely true, but may not reflect the significance of the teaching profession 104 to the identity of each individual 102 . For example, both a first individual 102 and a second individual 102 may have been continuously occupied as full-time teachers for thirty years, resulting in a high inference confidence that such facts 112 are indisputably accurate; but the first individual 102 may consider the fact 112 significant to his or her identity, while the second individual 102 may not. Indeed, the second individual 102 , having a thirty-year career as a teacher, may consider teaching to be less significant to his or her identity than a third individual 102 who has only been teaching for three months (and having a low inference confidence), or of a fourth individual 102 who aspires to be a teacher but has not yet been hired as such.
[0023] As a second such example, an individual 102 may reside in a particular location 114 , but the individual 102 may not consider the location 114 to be particularly interesting or distinguishing of the individual 102 . For example, virtually all of the individual's social connections may reside in New York, may all enjoy baseball, and may all appreciate cats. Populating the individual profile 110 of the individual 102 with these facts 112 may therefore not reflect anything distinctive or interesting about the individual 102 , especially if the individual 102 anticipates sharing this individual profile 110 with the individual's social contacts who share the same traits; indeed, such facts 112 may dilute the individual profile 110 and detract from other facts 112 that the individual 102 considers representative of the individual's identity.
[0024] As a third such example, a determination that the individual 102 frequently engages in a particular activity 116 may lead to an inference 118 of a fact 112 that the individual 102 has an interest 108 in the activity 116 . Even if the inference confidence is high, due to a very consistent and predictable frequency of the activity 116 , in some cases, the individual 102 may not consider the interest 112 to be representative of the individual's identity. For example, the individual 102 may regularly watch soccer as a professional sports reporter, or because the individual 102 enjoys spending time with family or friends who regularly watch soccer. However, such activities 116 may be only incidental to the identity of the individual 102 , and adding them to the individual profile 110 may not accurately reflect the individual's identity.
[0025] As a fourth such example, inferences 118 about the individual 102 may be achieved that identify facts 112 that the individual 102 considers to be private. Adding such facts 112 to a publicly accessible individual profile 110 , even if such inferences 118 have a high inference confidence and accurately represent the individual 102 , may not accurately reflect the identity that the individual 102 wishes to expose to the public.
[0026] In each such example, problems arise because even if the inference 118 about the individual 102 reflects a high inference confidence indicating that the fact 112 about the individual 102 is accurate, basing the individual profile 110 on such inferences may fail to account for whether such facts 112 are significant to the identity of the individual 102 . Indeed, in many cases, inference confidence and significance may be completely unrelated (e.g., an individual's self-perception that a fact 112 representing an activity 116 significantly represents the individual's interests may be unrelated to the frequency with which the individual 102 engages in the activity 116 ); and in many other cases, inference confidence and significance may be inversely related. For example, an individual 102 may frequently visit a first restaurant (resulting in a high inference confidence), and may infrequently visit a second restaurant (resulting in a low inference confidence). However, the first restaurant may be an easy, nearby, or affordable option that the individual 102 chooses out of habit or convenience, and the second restaurant may be the individual's favorite restaurant that the individual 102 chooses for special occasions. Contrary to the inference confidence of each option, the individual 102 may therefore consider the “special occasion” restaurant to be highly representative of the identity of the individual 102 , and may consider the convenient option not representative of the identity of the individual 102 . These and other disadvantages may arise from the generation of the individual profile 110 primarily relying upon the inference confidence of inferences 118 about the individual 102 .
B. Presented Techniques
[0027] Presented herein are techniques for automatically generating an individual profile 110 of an individual 102 in view of the significance of the respective facts 112 of the individual profile 110 to the identity of the individual 102 .
[0028] FIG. 2 presents an illustration of an example scenario 200 featuring the generation of an individual profile 110 in view of the significance 204 of the respective facts to the identity 218 of the individual 102 . In this example scenario 200 , at a detection time 202 , the individual 102 may be represented by an individual profile 110 that already includes a few facts 112 that the individual 102 considers significant to his or her identity 218 , such as the individual's location and profession. A determination may be made that the individual 102 has an interest 108 in soccer, and frequently engages in the activity 116 of playing the piano. However, an initial determination may be made of the significance 204 of each fact 112 to the identity 218 of the individual 102 . Because the initial determination of the significance 204 of each fact 112 is not above a significance threshold 208 , the facts 112 corresponding to the interest 108 and activity 116 are stored in storage 206 rather than in the individual profile 110 . The significance 204 of each fact 112 in storage 206 is the monitored (e.g., by comparing the respective facts 112 with additional expressions and activities 116 of the individual 102 ). At a second time 220 , when the individual 102 is further detected to engage in the activity 116 of playing soccer, the significance 204 of the interest 108 to the identity 218 of the individual 102 in the sport of soccer is determined to have exceeded the significance threshold 208 , and the fact 112 is moved from storage 206 to the individual profile 110 . Alternatively, at the second time 220 , the activity 116 of playing piano has not achieved a significance 204 to the identity 218 of the individual 102 that exceeds the significance threshold 208 within an evaluation duration 210 of the detection time 202 (e.g., the evaluation of the significance 204 of the piano-playing activity 116 has been evaluated for three days since the first instance of the activity 116 , and the individual 102 has not exhibited any further signs of interest in the activity 116 ). Rather than adding the activity 116 as a fact 112 to the individual profile 110 , a device may instead discard 216 the fact 112 corresponding to the activity 116 from storage 206 . In this manner, the individual profile 110 of the individual 102 is generated based on the evaluation of the significance 204 of respective facts 112 to the identity 218 of the individual 102 in accordance with the techniques presented herein.
C. Technical Effects
[0029] The use of the techniques presented herein to generate an individual profile 110 may result in a variety of technical effects.
[0030] As a first example of a technical effect that may be achievable by the techniques presented herein, the generation of the individual profile 110 based on the significance 204 of the facts 112 to the identity 218 of the individual 102 may enable the generation of an individual profile 110 that more accurately represents the identity 218 of the individual 102 . That is, the individual profile 110 is not diluted with facts 112 that are accurate but only incidental to the identity 218 of the individual 102 ; with facts 112 that are true of a large number of individuals 102 , and that therefore do not particularly distinguish the individual 102 ; and with facts 112 that are representative of the individual frequently performs out of habit, convenience, or obligation, but that are representative of the individual's choices. Limiting the facts 112 included in the individual profile 110 to those that have significance 204 to the identity 218 of the individual 102 may therefore provide a more concise individual profile 110 that more accurately reflects the identity 218 of the individual 102 . For example, if a first individual 102 requests to view the individual profile 110 of a second individual 102 , a device may respond by enumerating a small set of facts 112 that provide an insightful representation of the identity 218 of the second individual 102 , rather than a laundry list of facts 112 that may be accurate about the second individual 102 but may not reflect the identity 218 of the second individual 102 .
[0031] As a second example of a technical effect that may be achievable by the techniques presented herein, providing an automated evaluation of respective facts 112 , and an automated determination of the significance 204 of respective facts 112 to the identity 218 of the individual 102 , may reduce the interaction of the individual 102 to generate and maintain the individual profile 110 . For example, a device may generate an individual profile 110 comprising every possible fact 112 about a particular individual 102 , and may request or allow the individual 112 to choose and arrange the facts 112 according to their significance 204 to the identity 218 of the individual 112 . However, such manually curated individual profiles 110 may be frustrating for the individual 102 , and if the individual 102 does not regularly perform such manual curation, the facts 112 of the individual profile 110 may steadily diverge from the identity 218 of the individual 102 (e.g., facts 112 may become out of date, and new facts 112 may fail to be added). By contrast, the techniques presented herein enable an automated determination of the significance 204 of the facts 112 to the identity 218 of the individual 102 , and may therefore reduce the dependency on the manual curation of the individual profile 110 by the individual 102 .
[0032] As a third example of a technical effect that may be achievable by the techniques presented herein, the representation of a set of individuals 102 based on individual profiles 110 that are limited to facts 112 that have significance 204 to the identity 218 of the individual 102 may inform searches applied to the set of individuals 102 . For example, if an individual 102 searches among a social network for other individuals 102 who live in New York (e.g., for a recommendation of tourist destinations), it may not be helpful to provide a set of search results comprising every individual 102 whose individual profile 110 includes the fact 112 that the individual 102 resides or once resided in New York, as some individuals 102 may live in New York but may not be particularly interested in it; other individuals 102 may only occasionally live in New York; and still other individuals 102 may have previously lived in New York, but may no longer consider it a part of their identity 218 . Finding an individual 102 among such an individual set who is capable of and interested in presenting recommendations of New York tourist destinations may therefore be difficult. Conversely, limiting the search results to the individuals 102 for whom New York has a significance 204 to their identity 218 , including those who reside in New York and take an active interest in it, as well as those who have visited New York only occasionally but place great personal interest in such visits, may yield search results that are more suitable to the provided query.
[0033] As a fourth example of a technical effect that may be achievable by the techniques presented herein, limiting the individual profiles 110 of a set of individuals 102 to facts 112 that are associated with the significance 204 of the individual 102 may promote the scalability of services and processes that depend on such individual profiles 110 . For example, maintaining an exhaustive list of every fact 112 that may accurately describe each of many thousands of individuals 102 may involve significantly greater data storage, processing, and communication capabilities than limiting each individual profile 110 to a smaller set of facts 112 that have a significance 204 to the identity 218 of each individual 102 .
[0034] As a fifth example of a technical effect that may be achievable by the techniques presented herein, limiting the individual profiles 110 may enable a more thorough evaluation and monitoring of the significance 204 of such facts 112 to the identity 218 of the individual 102 . For example, attempting to monitor hundreds of facts 112 that might describe an individual 102 to maintain an updated inference confidence, e.g., every activity 116 that the individual 102 has performed at least once, and every restaurant that the individual 102 has visited at least once, may entail a significant expenditure of computational resources of the devices of the individual 102 , and may even scale to an unfeasible level of evaluation over many years of fact-gathering (e.g., the fact that the individual 102 watched a soccer game six years ago may not warrant a continued exploration of whether the sport of soccer is to be included in the individual profile 110 of the individual 102 ). Conversely, by limiting such evaluation to the facts 112 of the individual profile 110 that have previously been determined to have a significance 204 exceeding a significance threshold 208 , and to facts 112 that have recently been detected and are kept in storage 206 only briefly for the evaluation duration 210 , a device may apply a more thorough monitoring of the limited set of facts 112 that may result in a more accurate determination. Similarly, discarding 216 facts 112 that do not achieve a significance 204 above the significance threshold 208 within the evaluation duration 210 may enable a more rigorous significance evaluation of the smaller set of facts 112 that are currently kept in storage 206 . These and other technical effects may be achievable through the application of the techniques presented herein.
D. Example Embodiments
[0035] FIG. 4 presents a first example embodiment of the techniques presented herein, illustrated as an example method 300 of representing an individual profile 110 of an individual 102 . The example method 300 may be implemented, e.g., as a set of instructions stored in a memory component of a device, such as a memory circuit, a platter of a hard disk drive, a solid-state storage device, or a magnetic or optical disc, and organized such that, when executed on a processor of the device, cause the device to operate according to the techniques presented herein.
[0036] The example method 300 begins at 302 and involves executing 304 the instructions on a processor of the device. Specifically, executing 304 the instructions on the processor causes the device to, upon receiving 306 a fact 112 about the individual 102 at a detection time 202 , determine 308 a significance 204 of the fact 112 to the identity 218 of the individual 102 . Executing 304 the instructions may further cause the device to, upon determining that the significance 204 of the fact 112 to the identity 218 of the individual 102 exceeds a significance threshold 208 , add 310 the fact 112 to the individual profile 110 . Executing 304 the instructions may further cause the device to, upon failing to add the fact 112 to the individual profile 110 within an evaluation duration 210 of the detection time 202 , discard 312 the fact 112 about the individual 102 . In this manner, the instructions cause the device to represent the individual 102 with an individual profile 202 according to the techniques presented herein, and so ends at 314 .
[0037] FIG. 4 presents a second example embodiment of the techniques presented herein, illustrated as an example server 402 featuring a processor 404 and a memory 406 storing an example system 408 that causes the server 402 to generate an individual profile 110 of an individual 102 . The example system 408 may be implemented, e.g., as a set of components respectively comprising a set of instructions stored in the memory 406 of the server 402 , where the instructions of respective components, when executed on the processor 404 , cause the server 402 to operate in accordance with the techniques presented herein.
[0038] The example system 408 includes a significance evaluator 410 that determines a significance 204 of a fact 112 to the identity 218 of the individual 102 . The example system 408 also includes an individual profile manager 412 that, upon the significance evaluator 410 determining that the significance 204 of the fact 112 to the identity 218 of the individual 102 exceeds a significance threshold 208 , adds the fact 112 to the individual profile 110 ; and, upon failing to add the fact 112 to the individual profile 110 within an evaluation duration 210 of the detection time 202 , discards 216 the fact 112 about the individual 102 . In this manner, the example system 408 enables the server 402 to generate the individual profile 110 in accordance with the techniques presented herein.
[0039] Still another embodiment involves a computer-readable medium comprising processor-executable instructions configured to apply the techniques presented herein. Such computer-readable media may include various types of communications media, such as a signal that may be propagated through various physical phenomena (e.g., an electromagnetic signal, a sound wave signal, or an optical signal) and in various wired scenarios (e.g., via an Ethernet or fiber optic cable) and/or wireless scenarios (e.g., a wireless local area network (WLAN) such as WiFi, a personal area network (PAN) such as Bluetooth, or a cellular or radio network), and which encodes a set of computer-readable instructions that, when executed by a processor of a device, cause the device to implement the techniques presented herein. Such computer-readable media may also include (as a class of technologies that excludes communications media) computer-computer-readable memory devices, such as a memory semiconductor (e.g., a semiconductor utilizing static random access memory (SRAM), dynamic random access memory (DRAM), and/or synchronous dynamic random access memory (SDRAM) technologies), a platter of a hard disk drive, a flash memory device, or a magnetic or optical disc (such as a CD-R, DVD-R, or floppy disc), encoding a set of computer-readable instructions that, when executed by a processor of a device, cause the device to implement the techniques presented herein.
[0040] An example computer-readable medium that may be devised in these ways is illustrated in FIG. 5 , wherein the implementation 500 comprises a computer-readable memory device 502 (e.g., a CD-R, DVD-R, or a platter of a hard disk drive), on which is encoded computer-readable data 504 . This computer-readable data 504 in turn comprises a set of computer instructions 506 configured to operate according to the principles set forth herein. In one such embodiment, the processor-executable instructions 506 may be configured to perform a method 608 of generating an individual profile 110 of an individual 102 , such as the example method 300 of FIG. 3 . In another such embodiment, the processor-executable instructions 506 may be configured to implement a system for generating an individual profile 110 of an individual 102 , such as the example system 408 of FIG. 4 . Many such computer-readable media may be devised by those of ordinary skill in the art that are configured to operate in accordance with the techniques presented herein.
E. Variations
[0041] The techniques discussed herein may be devised with variations in many aspects, and some variations may present additional advantages and/or reduce disadvantages with respect to other variations of these and other techniques. Moreover, some variations may be implemented in combination, and some combinations may feature additional advantages and/or reduced disadvantages through synergistic cooperation. The variations may be incorporated in various embodiments (e.g., the example method 300 of FIG. 3 ; the example system 408 of FIG. 4 ; and the example memory device 502 of FIG. 5 ) to confer individual and/or synergistic advantages upon such embodiments.
E1. Scenarios
[0042] A first aspect that may vary among embodiments of these techniques relates to the scenarios wherein such techniques may be utilized.
[0043] As a first variation of this first aspect, the techniques presented herein may be utilized to achieve the configuration of a variety of devices, such as workstations, servers, laptops, tablets, mobile phones, game consoles, portable gaming devices, portable or non-portable media players, media display devices such as televisions, appliances, home automation devices, and supervisory control and data acquisition (SCADA) devices.
[0044] As a second variation of this first aspect, the techniques presented herein may be utilized to partition and use various types of individual profiles 11 -, including social networking and social media profiles; academic and/or professional individual profiles; gaming profiles provided for a gaming service; media profiles for individuals 102 producing and/or consuming various types of media; individual behavior profiles of devices that monitor the behavior of the individual 102 ; governmental profiles of the civic details of various individuals 102 ; financial profiles of the financial status of various individuals 102 ; and commercial profiles of the savings and/or purchasing behaviors of various individuals 102 .
[0045] As a third variation of this first aspect, the techniques presented herein may involve the evaluation of many types of facts 112 that may describe the individual 102 , including those specified directly by the individual 102 ; those specified by a first individual 102 about a second individual, such as a referral service; those detected about the individual 102 , such as a device that monitors one or more activities 116 of the individual 102 (e.g., a global positioning system that tracks the movement of the individual 102 ); and inferences 118 about the individual 102 (e.g., behavioral or personality traits about the individual 102 based on statistical and/or demographic factors, such as an inferred income level of an individual 102 based on the average income in a neighborhood including the personal residence of the individual 102 ).
[0046] As a fourth variation of this first aspect, the individual profile 110 may be used to provide various types of services on behalf of the individual 102 , such as a commercial service; a product, media, or service recommendation service; a social network or referral service; a matchmaking service, such as a dating service or a multiplayer game matchmaking service; an employment service; an information delivery service; and an advising service, such as a financial or career advising service. Many such scenarios may provide a context for utilizing the techniques presented herein.
E2. Significance Determination
[0047] A second aspect that may vary among embodiments of the presented techniques involves the manner of determining the significance 204 of a fact 112 to the identity 218 of the individual 102 , and may utilize various sources of information to determine the significance 204 of the fact 112 to the identity 218 of the individual 102 .
[0048] As a first variation of this second aspect, an embodiment may determine the significance 204 of the fact 112 by detecting, among an expression set of expressions by the individual 102 , an expression of whether the fact 112 has significance 204 to the individual 102 . As a first such example, the individual 102 may expressly indicate that a fact 112 is significant to the identity 218 of the individual 102 (e.g., “I love golfing!”), or may indicate that a fact 112 is not significant to the identity 218 of the individual 102 (e.g., “I don't really like pizza”). As a second such example, the individual 102 may indicate the significance 204 of facts 112 while manually curating the individual profile 110 ; e.g., when the individual 102 adds, approves, and/or highlights a fact 112 in the individual profile 110 , the fact 112 may be construed as having significance 204 to the identity 218 of the individual 102 ; whereas if the individual 102 removes, disapproves, and/or downplays a fact 112 in the individual profile 110 , the fact 112 may be construed as not having significance 204 to the identity 218 of the individual 102 . In one such embodiment, the individual 102 may specify a fact order of the respective facts 112 of the individual profile 110 , wherein a first fact 112 having an earlier fact order in the individual profile is more significant than a second fact 112 having a later fact order in the individual profile; and the fact order of each fact 112 may be construed as relating to the significance 204 of the fact 112 to the identity 218 of the individual 102 .
[0049] As a second variation of this second aspect, an embodiment may determine the significance 204 of the fact 112 by detecting, among an expression set of expressions by the individual, a frequency of references to the fact 112 by the individual 102 . For example, a fact 112 may be more likely to be related to the identity 218 of an individual 102 who frequently refers to and/or spontaneously raises the fact 112 in conversations, status messages, or content items such as written articles, or who generates sound, images, or video recordings that are related to the fact 112 , than an individual 102 who seldom refers to and/or spontaneously raises the fact 112 .
[0050] As a third variation of this second aspect, the significance 204 of the fact 112 to the identity 218 of the individual 102 may be determined by detecting activities according to the activity conformity of the activities 116 performed by the individual 102 . For example, for the respective activities 116 performed by the individual 102 , an embodiment may determine whether the activity 116 conforms with the fact 116 , and the significance 204 may be determined proportionally with the activity conformity frequency of the conforming activities 116 . As a further variation, the activities 116 so assessed may be distinguished between activities 116 that the individual 102 performs out of significant choices, and the activities 116 that the individual 102 performs out of obligation, habit, or convenience. That is, the determination of significance 204 may focus on the activities 116 that the individual 102 chooses when presented with a selection of viable options, and may factor out the activities 116 for which the individual 102 does not have a choice (e.g., forgoing an opportunity to watch a soccer game due to a conflicting school or work obligation may not be construed as diminishing the significance 204 of the interest 108 of the individual 102 in the sport of soccer).
[0051] FIG. 6 presents an illustration of an example scenario 600 featuring the determination of the significance 204 of various facts 112 to the identity 218 of an individual 102 . In this example scenario 600 , the facts 112 relates to the interest of the individual 102 in various activities 116 , such as golfing, hiking, and rock climbing. An embodiment may detect that among the expressions 602 of the individual 102 (e.g., messages exchanged with the individual's acquaintances in a social network), the individual 102 references golfing with a high frequency 604 , references golfing with a lower frequency 604 , and never references rock climbing. The embodiment may also detect that, when presented with opportunities to perform activities 116 , the individual 102 frequently chooses hiking 116 , but never chooses golfing, and instead chooses opportunities to engage in other activities 116 over the activity 116 of golfing. An embodiment may interpret such frequencies 604 in a variety of ways. With respect to hiking, since the individual both references hiking in expressions 602 and performs activities 116 that conform with the fact 112 , the fact 112 of an interest 108 in hiking may be determined to have a high significance 204 to the identity 218 of the individual. However, with respect to rock climbing and golfing, an embodiment may determine that the discrepancy between the frequency 604 of references to the fact 112 in the expressions of the individual 102 and the frequency 604 of the activity conformity of the activities 116 with the fact 112 may indicate that the fact 112 does not have high significance 204 to the individual 102 . An embodiment may further evaluate whether such discrepancy is due to a low significance 204 of the fact 112 to the individual 102 (e.g., the individual frequently discusses golfing as a business development opportunity, but does not choose to participate in golfing because the individual does not actually like golfing) or whether the discrepancy is due to limitations that are not related to the significance 204 of the fact 112 (e.g., whether the individual would engage in golfing 602 more frequently, but is unable to do so because of an injury or the unavailability of nearby golf courses).
[0052] When presented with conflicting information about the significance 204 of a fact 112 , embodiments may utilize a variety of techniques to identify the significance 204 of the fact 112 to the identity 218 of the individual 102 . In particular, techniques involving learning algorithms may be well-suited for reconciling such conflicting information. As one example, an artificial neural network may be trained to determine the significance 204 of a fact 112 using a training data set that identifies, for a set of facts 112 pertaining to a set of individuals 102 , the frequencies 604 of expressions 602 and activities 116 performed by the individuals 102 , and the significance 204 of the facts 112 to the identity 218 of each individual 102 as self-reported by the individuals 102 . Such self-identification may enable the learning network to assess which qualities reflect the significance 204 of each fact 112 to the identity 218 of an individual 102 . For example, a first fact 112 that represents an interest 108 in a “spectator sport,” such as professional football, may be readily determined by the frequency 604 of expressions 602 , and less proportional with the performance of related activities 116 such as actually playing football; whereas a second fact 112 that involves interests 108 that are performance-based, such as yoga, may be more readily assessed by the frequency 604 of the individual's performance of the activity 116 than by the frequency 604 with which the individual 102 references the activity 116 in expressions 602 . A learning algorithm, such as an artificial neural network, may be able to determine the factors about a fact 112 that most consistently relate to the self-reported significance 204 of the fact 112 to the identity 218 of the individual 102 , and once trained using a training data set, may be applied to the expressions 602 and activities 116 of individuals 102 to determine the significance 204 of such facts 112 to the identities thereof, in accordance with the techniques presented herein.
E3. Supplemental Information
[0053] A third aspect that may vary among embodiments of the techniques presented herein relates to the use of supplemental information that, together with the determination of the significance 204 of a fact 112 to the identity 218 of an individual 102 , enables a determination of whether to add the fact 112 to the individual profile 110 of the individual 102 .
[0054] As a first variation of this third aspect, the significance 204 of the fact 112 to the identity 218 of the individual 102 may involve a consideration of the sensitivity of the fact 112 to the individual 102 . In some scenarios, a fact 112 may be accurate and even significant to the individual 102 , but may also be considered by the individual 102 to be private and/or sensitive, and therefore not having significance 204 to the public identity 218 of the individual 102 . Accordingly, an embodiment may predict the sensitivity of the individual to acknowledging a fact 112 , and may discard facts 112 where the predicted sensitivity of the individual 102 exceeds a sensitivity threshold. Such prediction may be based on particular facts 112 (e.g., determining that a particular fact 112 is generally regarded as a “guilty pleasure,” such as an interest 108 in an unpopular musical group), and may evaluate the fact 112 as having low significance 204 to the identity 218 of the individual 102 unless the individual 102 expressly acknowledges the fact 112 . Alternatively or additionally, the sensitivity of individuals 102 may be determined on a cultural basis. For example, a fact 112 may be considered sensitive to individuals 102 of a first demographic, but not sensitive to individuals 102 of a second demographic (e.g., individuals 102 of a first age range may openly appreciate a particular television show, but individuals 102 of a second age range who appreciate the same television show may be reluctant to admit such interest 108 ). Accordingly, the significance 204 of a fact 112 to the identity 218 of an individual 102 may be predicted by determining a demographic trait of the individual 102 , and determining a demographic sensitivity to the fact 112 among an individual set of individuals 102 that exhibit the demographic trait.
[0055] FIG. 7 presents an illustration of an example scenario 700 wherein the individual sensitivity 702 of the individual is taken into consideration while determining whether to add a fact 112 to the individual profile 110 of an individual 102 . In this example scenario 700 , a fact 112 is evaluated as having either a high, medium, or low significance 204 to the identity 218 of an individual 102 . Additionally, the individual 102 is predicted as having either high, medium, or low individual sensitivity 702 to acknowledging the fact 112 as significant to the identity 218 of the individual 102 . Accordingly, an embodiment (such as an individual profile manager 512 ) may take into consideration both the significance 204 and the individual sensitivity 702 of the fact 112 to the identity 218 of the individual 102 , and may therefore determine 704 whether to discard the fact 112 or add the fact 112 to the individual profile 110 of the individual 102 .
[0056] As a second variation of this third aspect, in addition to considering the significance 204 of a fact 112 to the identity 218 of an individual, an embodiment may take into consideration the inference confidence of an inference 118 upon which the fact 112 is based. Contrasting with the example scenario 100 of FIG. 1 in which the inference confidence of the inference 118 is the primary determinant of adding the fact 112 to the individual profile 110 , in this third variation, the inference confidence of the inference 118 may be considered together with the significance 204 of the resulting fact 112 to the identity 218 of the individual 102 .
[0057] FIG. 8 presents an illustration of an example scenario 800 featuring a first technique for determining an inference confidence 802 indicating whether an inference 118 accurately reflects a fact 112 about an individual 102 . In this example scenario 800 , a first fact 112 kept in storage 206 (and not yet included in the individual profile 110 ) reflects an interest 108 of the individual 102 in a particular activity 116 , such as fishing. However, an inference confidence 802 of the inference 118 may be comparatively low, e.g., only 50% confidence that the fact 112 is accurate about the individual 102 . Because such an inference confidence 802 may be “borderline,” i.e., not sufficient either to add the fact 112 to the individual profile 110 or to discard the fact 112 , an embodiment may directly query the individual 102 about his or her interest 108 in the activity 116 , e.g., presenting a fact query 804 such as “do you like fishing?” A detection of an individual acknowledgment 810 of the fact 804 may enable an adjustment 808 of the inference confidence 802 that, in addition to the determination of the significance 204 of the fact 112 to the identity 218 of the individual 102 , enables a determination of whether to add the fact 112 to the individual profile 110 or to discard the fact 112 . As a second such example, rather than directly querying the individual 102 , an embodiment may subtly prompt the individual 102 for an expression of individual interest 810 . For example, an embodiment may present to the individual 102 a fact detail 812 about the fact 112 (e.g., a link to reviews of hiking gear), and may detect whether or not the individual 102 exhibits individual interest 810 in the fact detail 812 . A detection of individual interest 810 in the fact detail 812 may enable an adjustment 808 of the inference confidence 802 that, in addition to the determination of the significance 204 of the fact 112 to the identity 218 of the individual 102 , enables a determination of whether to add the fact 112 to the individual profile 110 or to discard the fact 112 . As a third such example, an embodiment may endeavor to determine an interference confidence 802 in a selected fact 112 (e.g., an inference that the individual 102 is interested in hiking) by presenting an option set including an option that is associated with the selected fact 112 (e.g., a link to reviews of hiking gear), and other options associated with alternative facts 112 in which the individual 102 has not expressed an individual interest 810 (e.g., interests in fishing and golfing). A detection of individual interest 810 in the option associated with the selected fact 112 that exceeds the options associated with the alternative facts may enable an adjustment 808 of the inference confidence in the selected fact 112 . Many such forms of supplemental information may be utilized together with the significance 204 of the fact 112 to the identity 218 of the individual 102 while determining whether or not to add the fact 112 to the individual profile 110 of the individual 102 in accordance with the techniques presented herein.
E4. Inclusion of Fact in Individual Profile
[0058] A fourth aspect that may vary among embodiments of the techniques presented herein involves the determination of whether to add a fact 112 to the individual profile 110 of the individual 102 , or to discard the fact 112 and/or exclude the fact 112 from the individual profile 110 of the individual 102 .
[0059] As a first variation of this fourth aspect, for a fact 112 in storage 206 and under evaluation to determine its significance 204 to the identity 218 of the individual 102 , the evaluation time 210 may be terminated if the individual 102 expressly indicates that the fact 112 has significance 204 to the identity 218 of the individual 102 , and/or if the individual 102 expresses a disavowal of the fact 112 as having significance 204 to the identity 218 of the individual 102 . The fact 112 may be accordingly added to the individual profile 110 and/or discarded from storage 206 , even if the evaluation duration 210 from the detection time 202 has not yet elapsed. Alternatively or additionally, after a fact 112 has been added to the individual profile 110 , the fact 112 may be excluded from the individual profile 110 if the individual 102 expresses a disavowal of the fact 112 .
[0060] As a second variation of this fourth aspect, an embodiment may adjust the evaluation duration 210 according to a confidence of the significance 204 of the fact 112 to the identity 218 of the individual 102 . For example, if a fact 112 in storage 206 is determined to have a significance 204 that remains consistently low during the evaluation period, the evaluation duration 210 may be shortened. Conversely, if a fact 112 in storage 206 is determined to have a steadily progressing significance 204 that is approaching the significance threshold 208 , or has a significance 204 that is near the significance threshold 208 as the evaluation duration 210 nears completion, the evaluation duration 210 may be extended to provide additional evaluation time.
[0061] As a third variation of this fourth aspect, the individual profile 110 may include a fact limit (e.g., the presentation of no more than ten facts 112 about the individual 102 ). If a fact count of facts 112 in the individual profile 110 exceeds the fact limit, an embodiment may remove one or more facts having a lower significance 204 to the identity 218 of the individual 102 than other facts 112 of the individual profile 110 . This variation may enable facts 112 having high significance 204 to the identity 218 of the individual 102 to replace facts 112 having lower significance 204 to the identity 218 of the individual 102 , e.g., as the identity 218 of the individual 102 changes and/or as new information about the individual 102 is detected.
[0062] As a fourth variation of this fourth aspect, after adding a fact 112 to the individual profile 110 of an individual 102 , an embodiment may continue to monitor the significance 204 of the fact 112 to the identity 218 of the individual 102 . Upon detecting that the significance 204 of the fact 112 to the identity 218 of the individual 102 has diminished below the significance threshold 208 (e.g., determining that an interest 108 of the individual 102 has faded to the point where the interest 108 no longer has significance 204 to the identity 218 of the individual 102 ), the embodiment may remove the fact 112 from the individual profile 110 of the individual 102 .
[0063] FIG. 9 presents an illustration of an example scenario 900 wherein the significance 204 of an activity 116 to an identity 218 of an individual 102 is monitored over time. In this example scenario 900 , at a first time 904 , a frequency 604 of the activity 116 performed by the individual 102 is determined (e.g., the individual 102 hikes during 60% of free weekends), and may be construed as a high significance 204 of the fact 112 that the individual 102 enjoys the activity 116 of hiking. Accordingly, the fact 112 may be added to the individual profile 110 of the individual 102 . At a second time 906 after the first time 904 , the frequency 604 of the activity 116 may be determined to be diminishing and therefore indicating a lower significance 204 of the fact 112 to the identity 218 of the individual 102 . At a third time 908 after the second time 906 , the frequency 604 of the activity 116 may be determined to have diminished to a point where the individual 102 seldom performs the activity 116 , indicating a low significance 204 of the fact 112 to the identity 218 of the individual 102 , and prompting an exclusion 902 of the fact 112 from the individual profile 110 of the individual 102 .
[0064] As a fifth variation of this fourth aspect, techniques may be utilized to reconcile conflicting facts 112 about the individual 102 . For example, an embodiment may detect that an individual 102 has expressed interest 108 in each of two rival sports teams, or in each of two opposite political parties. An embodiment may initiate monitoring the significance 204 of each fact 112 to determine which fact 112 is more representative of the identity 218 of the individual 102 , and may adjust the individual profile 110 according to such determination. As one such example, an embodiment simply present to the individual a request to confirm the conflicting fact 112 that conflicts with a first fact 112 , and upon receiving confirmation of the conflicting fact 112 , the embodiment may exclude the first fact 112 from the individual profile 110 of the individual 102 . Many such techniques may be utilized to determine which facts 112 to include in the individual profile 110 of the individual 102 in accordance with the techniques presented herein.
F. Computing Environment
[0065] FIG. 10 and the following discussion provide a brief, general description of a suitable computing environment to implement embodiments of one or more of the provisions set forth herein. The operating environment of FIG. 10 is only one example of a suitable operating environment and is not intended to suggest any limitation as to the scope of use or functionality of the operating environment. Example computing devices include, but are not limited to, personal computers, server computers, hand-held or laptop devices, mobile devices (such as mobile phones, Personal Digital Assistants (PDAs), media players, and the like), multiprocessor systems, consumer electronics, mini computers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
[0066] Although not required, embodiments are described in the general context of “computer readable instructions” being executed by one or more computing devices. Computer readable instructions may be distributed via computer readable media (discussed below). Computer readable instructions may be implemented as program modules, such as functions, objects, Application Programming Interfaces (APIs), data structures, and the like, that perform particular tasks or implement particular abstract data types. Typically, the functionality of the computer readable instructions may be combined or distributed as desired in various environments.
[0067] FIG. 10 illustrates an example of a system 1000 comprising a computing device 1002 configured to implement one or more embodiments provided herein. In one configuration, computing device 1002 includes at least one processing unit 1006 and memory 1008 . Depending on the exact configuration and type of computing device, memory 1008 may be volatile (such as RAM, for example), non-volatile (such as ROM, flash memory, etc., for example) or some combination of the two. This configuration is illustrated in FIG. 10 by dashed line 1004 .
[0068] In other embodiments, device 1002 may include additional features and/or functionality. For example, device 1002 may also include additional storage (e.g., removable and/or non-removable) including, but not limited to, magnetic storage, optical storage, and the like. Such additional storage is illustrated in FIG. 10 by storage 1010 . In one embodiment, computer readable instructions to implement one or more embodiments provided herein may be in storage 1010 . Storage 1010 may also store other computer readable instructions to implement an operating system, an application program, and the like. Computer readable instructions may be loaded in memory 1008 for execution by processing unit 1006 , for example.
[0069] The term “computer readable media” as used herein includes computer-readable memory devices that exclude other forms of computer-readable media comprising communications media, such as signals. Such computer-readable memory devices may be volatile and/or nonvolatile, removable and/or non-removable, and may involve various types of physical devices storing computer readable instructions or other data. Memory 1008 and storage 1010 are examples of computer storage media. Computer-storage devices include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVDs) or other optical storage, magnetic cassettes, magnetic tape, and magnetic disk storage or other magnetic storage devices.
[0070] Device 1002 may also include communication connection(s) 1016 that allows device 1002 to communicate with other devices. Communication connection(s) 1016 may include, but is not limited to, a modem, a Network Interface Card (NIC), an integrated network interface, a radio frequency transmitter/receiver, an infrared port, a USB connection, or other interfaces for connecting computing device 1002 to other computing devices. Communication connection(s) 1016 may include a wired connection or a wireless connection. Communication connection(s) 1016 may transmit and/or receive communication media.
[0071] The term “computer readable media” may include communication media. Communication media typically embodies computer readable instructions or other data in a “modulated data signal” such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” may include a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal.
[0072] Device 1002 may include input device(s) 1014 such as keyboard, mouse, pen, voice input device, touch input device, infrared cameras, video input devices, and/or any other input device. Output device(s) 1012 such as one or more displays, speakers, printers, and/or any other output device may also be included in device 1002 . Input device(s) 1014 and output device(s) 1012 may be connected to device 1002 via a wired connection, wireless connection, or any combination thereof. In one embodiment, an input device or an output device from another computing device may be used as input device(s) 1014 or output device(s) 1012 for computing device 1002 .
[0073] Components of computing device 1002 may be connected by various interconnects, such as a bus. Such interconnects may include a Peripheral Component Interconnect (PCI), such as PCI Express, a Universal Serial Bus (USB), Firewire (IEEE 1394), an optical bus structure, and the like. In another embodiment, components of computing device 1002 may be interconnected by a network. For example, memory 1008 may be comprised of multiple physical memory units located in different physical locations interconnected by a network.
[0074] Those skilled in the art will realize that storage devices utilized to store computer readable instructions may be distributed across a network. For example, a computing device 920 accessible via network 1018 may store computer readable instructions to implement one or more embodiments provided herein. Computing device 1002 may access computing device 920 and download a part or all of the computer readable instructions for execution. Alternatively, computing device 1002 may download pieces of the computer readable instructions, as needed, or some instructions may be executed at computing device 1002 and some at computing device 920 .
G. Usage of Terms
[0075] Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
[0076] As used in this application, the terms “component,” “module,” “system”, “interface”, and the like are generally intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a controller and the controller can be a component. One or more components may reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers.
[0077] Furthermore, the claimed subject matter may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed subject matter. The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of the claimed subject matter.
[0078] Various operations of embodiments are provided herein. In one embodiment, one or more of the operations described may constitute computer readable instructions stored on one or more computer readable media, which if executed by a computing device, will cause the computing device to perform the operations described. The order in which some or all of the operations are described should not be construed as to imply that these operations are necessarily order dependent. Alternative ordering will be appreciated by one skilled in the art having the benefit of this description. Further, it will be understood that not all operations are necessarily present in each embodiment provided herein.
[0079] Any aspect or design described herein as an “example” is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word “example” is intended to present one possible aspect and/or implementation that may pertain to the techniques presented herein. Such examples are not necessary for such techniques or intended to be limiting. Various embodiments of such techniques may include such an example, alone or in combination with other features, and/or may vary and/or omit the illustrated example.
[0080] As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims may generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.
[0081] Also, although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The disclosure includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated example implementations of the disclosure. In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms “includes”, “having”, “has”, “with”, or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” | In many computing scenarios, individual profiles are generated from facts specified by, observed about, and/or inferred about individuals, and may be used to personalize services to such individual. Such facts may include details provoking a sensitivity of an individual, and it may be undesirable to reveal the collection and use of such facts to the individual; however, such facts may also enable accurately personalized service. These considerations may be balanced by partitioning the individual profile into a foreground profile, comprising facts that are revealed to the individual, and a background profile, comprising facts that are collected about but not revealed to the individual. Services may be covertly personalized for the individual based on the sensitive information stored in the background profile (e.g., restaurant recommendations that are overtly recommended based on the current location of the individual, and also covertly selected based on an inferred income level of the individual). | 6 |
FIELD OF THE INVENTION
This invention relates to wheel balancers and speed nuts therefor whereby the mounting and the demounting of a wheel on the shaft of a wheel balancer may be expedited.
BACKGROUND ART
In recent years, there has been a vast upsurge in the use of highly sophisticated wheel balancers for balancing wheels prior to their mounting on a vehicle. Such wheel balancers typically employ highly sensitive electronic circuitry and sensors for determining the location and degree of imbalance of a wheel mounted on a shaft forming part of the wheel balancer and which is driven.
In the typical wheel balancer, there is a locating device, frequently in the form of a spring biased cone, surrounding the shaft at the driven end thereof so as to precisely center the wheel about the rotational axis of the shaft. The shaft typically is threaded and a nut is threaded onto the shaft to engage the wheel and firmly hold the same against the locating device prior to testing. Thus, in order to mount or demount a wheel from the shaft, it is necessary to thread the nut onto the shaft or thread the nut off of the shaft, as the case may be.
Because of the large variety of vehicle wheels which are balanced on such wheel balancers, provision must be made in the wheel balancer to accomodate the vast majority of such differing wheel types. This has frequently required that the shaft, or an extension thereof, be relatively long. As a consequence, considerable time may be spent rotating the nut structure on the shaft to the point that it properly engages the wheel in a mounting operation or in rotating the nut to remove the same from the shaft to allow the wheel to be demounted from the balancer. This time spent is costly in terms of labor expense and, in volume operations, considerably decreases the efficiency of the operation by diminishing the number of wheels that may be balanced on a wheel balancer in a given period of time.
SUMMARY OF THE INVENTION
It is the principal object of the invention to provide a new and improved wheel balancer. More specifically, it is the object of the invention to provide a new and improved wheel balancer wherein the time spent in mounting or demounting a wheel therefrom is considerably minimized to thereby effect labor and time savings in each wheel balancing operation.
An exemplary embodiment of the invention achieves the foregoing object in a wheel balancer including a threaded shaft having a free end for receiving a wheel to be balanced. The balancer includes means for rotating the shaft with a wheel secured thereon so as to enable the obtaining of data relative to unbalance of the wheel as the wheel rotates. A locating device is utilized for engaging a wheel on the shaft for locating the wheel properly thereon such that it is centered upon the rotational axis of the shaft. Nut means are provided on the shaft for holding a wheel thereon and against the locating device. The nut means includes nut threads for engagement with the threads of the shaft and means for selectively moving the nut threads radially inwardly into engagement with the shaft threads or radially outwardly out of engagement with the shaft threads so that the nut means may be rapidly advanced on or removed from the shaft without rotation when the nut threads are out of engagement with the shaft threads.
According to another facet of the invention, there is provided a speed nut for use on a threaded shaft which includes at least two threaded elements each having an arc length of 180° or less. Means mount the elements for movement toward and away from each other between first positions for engaging the threads on a shaft and second positions for disengagement from threads on a shaft. Means are provided for normally urging the elements toward the second position and there are utilized means responsive to an axial force in the nut for moving the elements to the first positions. Means are provided which cooperate with a threaded shaft and are responsive to engagement of the elements with a threaded shaft and a compressive axial force on the nut for holding the elements in the first position.
As a consequence, the nut may be slid onto a threaded shaft and the requisite forces applied to the nut structure to first cause engagement of the threaded elements with the threaded shaft and then hold such elements in such engagement until the compressive forces release. At that time, threaded elements will automatically return to the second positions out of engagement with the threads on the shaft allowing the nut to be slidably removed therefrom. Thus, the nut structure need only be rotated for final tightening or initial loosening avoiding excessive time spent in placing the structure on or removing it from a shaft.
Other objects and advantages will become apparent from the following specification taken in connection with the drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a wheel balancer embodying the speed nut and made according to the invention; and
FIG. 2 is an enlarged, sectional view of the speed nut.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An exemplary embodiment of a wheel balancer made according to the invention is illustrated in FIG. 1 and includes a wheel balancer frame shown somewhat schematically at 10 which journals a rotatable, threaded shaft 12. Means 14 forming part of the wheel balancer are suitably coupled to the shaft 12 for rotating the same and as is conventional, suitable sensors and detecting circuitry which may be of a conventional nature (not shown) are utilized for acquiring data to determine the degree of imbalance of a wheel 16 having a tire 18 thereon which is rotated with the shaft 12. Typically, such circuitry will provide not only an indication of where one or more balancing weights should be placed on the wheel 16, but an indication of the amount of such weight as well.
Typically, the balancer will include a cup-like locating structure 20 concentric with the shaft 12 which mounts a conical locating element 22 for movement along the axis of the shaft 12. A spring 24 contained within the cup 20 is employed to bias the cone 22 towards the free end 26 of the shaft so that the same may enter the center opening 28 of the wheel 16 to center the wheel about the rotational axis of the shaft 12. A nut structure, generally designated 30, is disposed on the shaft 12 and is in engagement with the wheel 16 on the side thereof opposite from the cone 22. The nut structure 30 is operative to hold the wheel firmly against the locating cup 20 and the cone 22 as well as to retain the wheel 16 on the shaft 12 to be rotated thereby. As can be seen, the nut structure 30 is provided with handles 32 whereby the same may be rotated on the shaft 12 when threaded elements to be described forming part of the nut structure 30 are in engagement with the threads 34 on the shaft 12.
Turning now to FIG. 2, the nut structure 30 will be described in greater detail. The same includes a cup 40 having a flat end surface 42 for engagement with the wheel and an interior, annular recess 44 for receipt of so much of the locating element that may extend through the wheel 16 to the opposite side thereof. The base of the cup 40 includes a circular opening 46 which receives a collar 48 formed of Teflon® or the like, the collar 48 having a radially outwardly extending, peripheral flange 50 and serving as a spacer for purposes to be seen.
Received within the collar 48 is a front guide 52 having a central circular opening 54 having a slightly larger diameter than the diameter of the apex of the threads 34 on the shaft 12 (FIG. 1) so as to be slidable thereon. On its outer surface, the front guide 52 includes an annular, radially outwardly opening recess 56 for receipt of a lock ring 58 which abuts both one end of the collar 48 and the base of the cup 40 for locating purposes.
The front guide 52 also includes an interior conical surface 60 whose smallest diameter is considerably greater than the diameter of the opening 54 and which acts as a ramp-like surface for purposes to be seen. Adjacent the narrowest portion of the conical surface 60, the front guide 52 includes axially directed bores 62 for receipt of springs 64 which act against a thrust washer 66.
Two or more threaded elements 70 are slidably received on the conical surface 60. Each of the elements 70 contains multiple threads 72 configured for engagement with the threads 34 on the shaft 12 (FIG. 1) so that the nut structure 30 may advance in either direction on the shaft 12 when rotated by the handles 32, dependent upon the direction of such rotation. Each of the threaded elements 70 has an arc length of 180° or less where two such elements are used and each will have an arc length of 120° or less where three such elements are employed, etc.
In any event, the sides 74 of each of the threaded elements 70 will have a configuration corresponding to that of part of a cone similar to the cone surface 60.
The narrow ends 76 of each of the threaded elements bear against the thrust washer 66 while the wide ends 78 of each of the elements are provided with retention grooves 80.
An annular rear guide 82 is abutted against the lefthand end of the front guide 52 as seen in FIG. 2 and includes an annular, axially directed tongue 84 which is received in the retention grooves 80 of the elements 70.
As will be seen, the elements 70 move from a radially outermost position as illustrated in FIG. 2 wherein they will not engage the threads 34 on the shaft 12 to a radially innermost position wherein the threads 34 on the shaft 12 will be engaged by the threads 72 to couple the nut 30 to the shaft 12 by moving axially to the right as viewed in FIG. 2 thereby sliding upwardly and inwardly on the ramp-like surface defined by the cone 60. The arrangement is such, however, that the axial movement that is involved is limited by abutment of the thrust washer 60 with the front guide 52 with the axial length of the tongue 84 being greater than the maximum axial travel of the elements 70 providing for positive retention of the threaded elements 70 against the surface 60 at all times.
Disposed within the interior opening of the rear guide 82 is a slider 90 having surfaces 92 which engage portions of the wide ends 78 of the elements 70. The slider 90 may also include axial fingers 94 that extend between the threaded elements 70.
Cap screws 96 couple the slider 90 to a crankplate 98 bearing the handles 32. Both the slider 90 and the crankplate 98 have interior circular bores 100 and 102 of the same diameter as the opening 54 in the front guide 52.
Internal cap screws 106 couple the rear guide 82 to the front guide 52 and the heads of the cap screws 106 serve as locating devices for compression springs 108 which are received in bores 110 in the crankplate 98 to bias both the crankplate 98 and the slider 90 away from the cup 40.
Returning to the threads 34 and 72 and the surface 60, it should be observed that it is necessary that the angle of the surface 60 with respect to the rotational axis of the nut 30, which is, of course, the axis of the shaft 12 as well, be less than the angle of faces 112 of the threads 72 (and their counterparts on the threads 34) with respect to a plane at right angles to the axix. This interrelationship serves to hold the elements 70 in engagement with the threaded shaft 12 under desired circumstances that will be seen.
In operation, a wheel 16 to be balanced is placed on the shaft 12 via the free end 26 thereof and located on the cone 22 as illustrated. The nut 32 is then applied to the shaft 12 in the following manner. Initially, because of the bias of the springs 64 urging the threaded elements 70 to the left as viewed in FIG. 2, such elements will be in the radially outermost position and accordingly will be retracted with respect to the openings 54, 100 and 102 of the nut structure 30. Accordingly, the nut structure can be axially slid onto the shaft 12 without rotation until the end 42 of the cup 40 abuts the wheel 16. Further axial movement of the nut structure 30 will incur resistance due to the presence of the spring 24 in the balancer itself. As a consequence, continued application of such axial force will result in the crankplate 98 and the slider 90 moving to the right with respect to other nut structure components as viewed in FIG. 2. This will in turn cause the slider 90, by reason of its engagement with the ends 78 of the elements 70, to move the elements 70 axially to the right as viewed in FIG. 2 causing the same to be cammed radially inwardly and into engagement with the threads 34 on the shaft 12. Continued application of pressure by reason of manual force being exerted to telescope the crankplate 98 onto the remainder of the nut structure, will result in the threads 72 fully entering the threads 34 such that the faces 112 will be in face-to-face engagement with their counterparts on the shaft 12. The release of the axial compressive force at this point in time will not allow the springs 64 to move the elements 70 to their retracted position since, by reason of the angular relationship of the surface 60 and the faces 112 of the threads 72 to the shaft axis, an interference fit will be present. That is, because of the angular relationship, the faces 112 will not be free to slide on the mating spaces of the threads 34 and engagement will be maintained. At this time, the handles 32 may be utilized to impart a few turns of rotation to the nut structure 30 to securely locate the wheel 16 concentrically on the shaft 12 for rotation therewith. The balancing operation may then proceed.
When it is desired to remove the wheel 16 from the balancer, the nut structure 30 is rotated in the opposite direction by use of the handle a few turns until the spring 24 is no longer compressed. At this time, the engagement between the threaded elements 70 and the threaded shaft 12 will be loose allowing the elements 70 to retract under influence of the springs 64. The nut structure 30 may then be removed from the shaft 12 by axial sliding thereon and without rotation.
From the foregoing, it will be appreciated that a wheel balancer made according to the invention allows considerable time saving in the process of mounting and demounting wheels to be balanced on the balancer thereby effecting a considerable labor saving and allowing a fuller utilization of the balancer itself. | A wheel balancer having a threaded shaft with a free end for receiving a wheel to be balanced and a drive for rotating the shaft to a wheel secured thereon so as to enable the obtaining of data relative to imbalance of the wheel as the wheel rotates. A locating device is provided for engaging a wheel on the shaft to locate the wheel properly thereon and a nut is utilized in connection with the shaft for holding the wheel against the locating device. The nut includes apparatus for selectively moving the nut threads radially inwardly into engagement with the shaft threads and radially outwardly out of engagement with the shaft threads so that the nut may be rapidly advanced on or removed from the shaft without rotation when the nut threads are out of engagement with the shaft threads. | 5 |
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to the field of Semiconductor fabrication, and more specifically to a method of fabricating a self-aligned gate for use in semiconductor devices.
(2) Description of the Prior Art
Semiconductor devices are found in nearly all electronic devices. They can be made in miniature forms for use in integrated circuits. The introduction of the transistor and its continuing development in ever-smaller size is one of the major factors in the continued growth of the application of the transistor in a wide range of electronic devices such as personal computers, calculators and many others.
One type of transistor in wide use is the field effect transistor, which is manufactured and used in a number of varieties such as the metal-semiconductor field effect transistor (MESFET).
A controllable current can be established between the source and the drain electrode of this transistor with the current controlled by a voltage applied to a gate electrode that is positioned on the semiconductor substrate between the source and the gate electrode.
The performance of this type of transistor is, like most types of transistors, determined by its size and the therefrom following performance parameters. For the MESFET specifically the gate electrical resistance and capacitance are of importance. Higher capacitance and resistance are, from a performance point of view, undesirable since this reduces the high frequency performance of this transistor.
As the length of the contact surface or gate of the electrode parallel to the direction of current flow is reduced, the resistance of the gate electrode increases and its capacitance decreases. That is, as the gate length is made shorter, its resistance rises and becomes the dominant factor in limiting the operating frequency of the device.
Accordingly, there exists a need for a gate electrode geometry and fabrication that permits the fabrication of smaller gates for the use in field effect transistors and possibly other electronic devices.
In order to increase the operating frequency of a field effect transistor it is therefore in general required that the length of the gate is reduced. Therefore, in order to prevent increase of the gate resistance while shortening the length of the gate, a method in which a section of the gate has a T form is mostly used.
Current design approaches use the T-shaped gate construct to resolve these problems. The process can be implemented largely with individual processing steps that are known within the state of the art and which are fully compatible with related processing steps of field effect transistors and other semiconductor circuit elements.
It is the primary objective of the present invention to increase the quality of the Titanium Silicon layer, which is deposited on top of the drain and source within the construct of the field effect transistor.
Another objective is to allow fabrication of T-gate field effect transistors with very small gate length. As the gate length is reduced to very small values it becomes increasingly more difficult to form acceptable TiSi x on top of the gate source and drain areas. The present invention addresses this problem.
U.S. Pat. No. 5,498,560 (Sharma et al.) shows a T shaped gate using an opening and spacer process similar to the invention's 1 st method with the difference that the Sharma does not use a CMP.
U.S. Pat. No. 4,849,376 (Balzan et al.), U.S. Pat. No. 5,688,704 (Liu), U.S. Pat. No. 5,658,826 (Chung), U.S. Pat. No. 5,288,654 (Kasai et al.), U.S. Pat. No. 5,496,779 (Lee et al.), U.S. Pat. No. 4,975,382 (Takasugi), U.S. Pat. No. 4,700,462 (Beaubien) show T shaped gates.
U.S. Pat. No. 5,731,239 (Wong et al.) shows a silicide gate process.
SUMMARY OF THE INVENTION
The present invention is embodied in a multi-step process for fabricating electrodes for semiconductor devices, and particularly for fabricating electrodes for field effect transistors. For a gate length of 0.18 μm it is difficult to form Titanium Silicon (TiSi x ) layers as part of the formation of the field effect transistor. The present invention therefore proposes a method of forming a structure having a narrow contact area with a substrate and an extensive top portion.
Another objective of the present invention is to provide a method of forming a T gate structure that has acceptable resistance and capacitance characteristics within the electronic circuit where the T gate is used.
In accordance with the first embodiment of the present invention, a process for preparing a T gate electrode for use in a semiconductor device, the T gate having a foot in contact with a semiconductor substrate and an extensive head upon the foot and connected with the foot, comprises the steps of providing a semiconductor substrate, forming a Surrounding T-gate Insulator (STI), depositing a dielectric layer overlying the substrate, forming a first trench in the dielectric layer, forming sidewall spacers within the trench, developing a head profile within the spacer and the trench thereby, forming a second trench within the dielectric the T gate now has straight edges, deposit a metal layer overlaying the head profile thereby depositing metal into the foot profile and the head profile, perform Chemical Mechanical Planarization of the deposited metal layer down to the top of the deposited head structure, remove the dielectric layer to form the gate spacer and the T shaped gate, form Lightly Doped Drains around the foot of the T shaped gate using large angle implant to prevent performance degradation of the gate, deposit a layer of Titanium for the formation of TiS x across the head of the T gate and on top of the T gate and the previously formed T gate spacer forming the salicide.
In accordance with the second embodiment of the present invention, a process for preparing a T-gate electrode for use in a semiconductor device, the T-gate having a foot in contact with a semiconductor substrate and an extensive head upon the foot and connected with the foot, comprises the steps of providing a semiconductor substrate, forming a Surrounding T-gate Insulator (STI), depositing a dielectric layer overlying the substrate, forming a trench within the dielectric layer down to the level of the substrate, forming curved or bow shaped spacers within the trench, developing a head profile within the spacer and the trench where now the foot profile of the T gate has a dual curved profile, deposit a metal layer overlaying the head profile thereby depositing metal into the foot profile and the head profile, perform Chemical Mechanical Planarization of the deposited metal layer down to the top of the deposited head structure, remove the dielectric layer to form the gate spacer and the T shaped gate, form Lightly Doped Drains around the foot of the T shaped gate using large angle implant to prevent performance degradation of the gate, deposit a layer of Titanium for the formation of TiSix across the head of the T gate and on top of the T gate and the previously formed T gate spacer forming the salicide.
The T-gate structure of the present invention permits short contact length between the foot or downward extended central portion of the T, and the surface of the semiconductor substrate. This contact length forms the gate for the field effect transistor. The head or crosspiece contains a larger volume of metal than might otherwise be expected for the short gate length, thereby decreasing the electrical resistance of the T gate electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 through 6 show the first embodiment of the present invention.
FIG. 1 shows the formation of the Surrounding Trench Insulation (STI) and the deposition of a dielectric material.
FIG. 2 shows the etching of a trench in the dielectric material and the deposition of wall spacers.
FIG. 3 shows the etching of the dielectric material to form the T gate profile.
FIG. 4 shows the depositing of the head and foot structure of the T gate.
FIG. 5 shows the etching of the dielectric material around the T gate structure and the formation of gate spacers.
FIG. 6 shows the depositing of salicide.
FIGS. 7 through 11 show the second embodiment of the present invention.
FIG. 7 shows the formation of the STI and the depositing of the dielectric layer.
FIG. 8 shows the etching of a mushroom shaped trench and the formation of spacers within the trench.
FIG. 9 shows the depositing of the T shaped gate.
FIG. 10 shows the etching of the dielectric layer, the formation of LLD's, the formation of the T gate spacers and the source and drain regions within the structure.
FIG. 11 shows the formation of the salicide.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made to the preferred embodiments of the present invention, an example of which is illustrated in the accompanying drawings.
In fabricating the T-gate electrode on the surface of the semiconductor substrate, the dielectric layer is first deposited overlying the substrate, after this a photo-resist material is deposited overlaying the dielectric material. A line pattern is exposed into the resist layer with a single pass of a focussed electron beam or by any other means, which can define the five dimensions. In this manner the central regions of the exposed volume is highly exposed and the adjacent peripheral regions are significantly less heavily exposed. This gradient of exposure results primarily from natural beam dispersion in the resist material.
The deep, narrow trench that is etched into substrate should have sidewalls that are smooth and slightly tapered. There should be no undercutting of the mask that is used to define the trench width and no irregularities along the sidewalls. Control of the sidewalls of the trench is needed so that the trench can be refilled by CVD without the formation of voids.
FIG. 1 shows the depositing of the dielectric material 12, using standard Chemical Mechanical Depositing techniques, on top of the substrate 13. Prior to the depositing of the dielectric material 12 an insulating trench 11 has been formed within the substrate 13 and around the area where the T gate is to be formed so as to electrically insulate the T gate from the surrounding substrate area.
The line profile of the highly exposed region is developed using standard electron beam resists development procedures, typically wet chemical development. The result is a sharply defined, narrow line profile extending down to the dielectric material. This line profile is transferred to the dielectric layer using dry etching techniques, such as reactive ion etching, which permit transfer of a sharply defined profile rather than a profile that is ragged or diffused due to chemical effects.
FIG. 2 indicates the etching of the first trench 21 as described above. Nitride sidewall spacers (not shown) are fabricated within the first trench 21 and positioned along the walls of the trench.
In a Lightly Doped Drain (LDD) structure (see below) the drain is formed by two implants. One of these implants is self-aligned to the gate of the electrode; the other implant is self-aligned to the gate electrode on which two oxide sidewall-spacers have been formed. This technique is used within the present invention where the spacer is formed first while the Large-angle-tilt Implanted Drain (LATID) is used to form the LDD's.
A narrower profile for the foot of the T gate is developed in the region of more electron beam exposure in the resist material, using the standard development techniques such as wet chemical development that do not attack the dielectric and the head profile.
FIG. 3 shows the formation of the foot of the T gate by etching a narrower second trench 31 within trench 21. At this time the nitride wallspacers can be removed.
FIG. 4 shows the depositing of a conductive layer 41, which is preferably polysilicon but could also be a metal, over the whole structure and in doing so filling the foot structure 31 and the head structure 21 of the T gate with polysilicon 41. The top layer of the deposited polysilicon 41 is etched away to the level of the top of the head of the T gate using standard Chemical Mechanical Planarization techniques.
FIG. 5 shows how the oxide 12 is etched away from the sides of the head 54 of the T gate down to the substrate 13 leaving two oxide sidewall spacers 52 around the foot of the T gate. The T-gate 54 with the T gate sidewall spacers 52 are now complete. Large tilt angle implant 55 is used for the formation of the Lightly Doped Drains (LDD's).
It has previously been determined that hot-carrier effects into the gate oxide will cause unacceptable performance degradation in N-type Metal Oxide Semiconductor (NMOS) devices built with conventional drain structures if their channel length is less than 2 um. To overcome this problem, such alternative drain structure as double-diffused drains and lightly doped drains (LDD's) must be used. The purpose of both types of structures is the same that is to absorb some of the potential into the drain. The present invention uses LDD's.
In the LDD structure, the drain 51 is formed by two implants. One of these is self-aligned to the gate electrode 54, and the other is self-aligned to the gate electrode on which two oxide sidewall spacers have been formed (FIG. 2). The purpose of the lighter first dose is to form a lightly doped section of the drain 51 at the edge near the channel. This structure causes the voltage drop between the drain and the source to be shared by the drain and the channel in contrast to the conventional drain structure, in which almost the entire voltage drop occurs across the lightly doped channel region.
The T-gate structure that is the subject of the present invention forms part of the construction of a number of semiconductor devices, for instance the Metal Oxide Semiconductor Field Effect Transistor (MOSFET). This device has a gate terminal (to which the input signal is normally applied), as well as source and drain terminals across which the output voltage is developed, and through which the output current flows, i.e., the drain-source current. The gate terminal is connected to the gate electrode (a conductor) while the remaining terminals are connected to heavily doped source and drain regions in the semiconductor substrate.
A channel region in the semiconductor under the gate electrode separates the source and the drain. The channel is lightly doped with a dopant type opposite to that of the source and the drain. The semiconductor is also physically separated from the gate electrode by an insulating layer (typically SiO2) so that no current flows between the gate electrode and the semiconductor.
In a typical structure an N+ type drain is formed with an N+ type source, the N material is phosphorous or arsenic. An N-type material is typically used for the LDD infusion.
FIG. 6 shows the final step in the processing of the T-gate which is the formation of the salicide 61 that is formed on top of the head of the T-gate 41 and on both the source 51 gate and the drain gate 56.
As transistor dimensions approach 1 um, the conventional contact structures used up to that point began to limit device performance in several ways. First, it was not possible to minimize the contact resistance if the contact hole was also of minimum size and problems of cleaning the contact holes became a concern. In addition, the area of the source a and drain region s could not be minimized because the contact hole had to be aligned to these regions with a separate masking step, and extra area had to be allocated for misalignment. This larger area also resulted in increased source/drain-to-substrate junction capacitance that resulted in slowed down device speed. Also, the technique of using several small, uniform contact holes in stead of one relatively large hole, a technique used to assure simultaneous clearing of the holes during etching, resulted in reduced contact surface which results in in creased contact resistance.
A variety of alternate structures have been investigated in an effort to alleviate the indicated problems. One of structures is the use of self-aligned suicides on the source-drain regions, when these suicides are formed at the time as the polycide structure this approach is referred to as a salicide process. This process is used within the scope of the present invention.
The processing steps for the formation of salicide are well know and within the state of the art of semiconductor device manufacturing. The result of the formation of salicide is that the entire surface of the source and the drain regions become contact structures.
FIGS. 7 through 11 show an alternate method to the process just described. The processing sequence as indicated within these figures is different in that the foot of the T-gate is not a rectangular structure but has side walls 70 which are curved or parabolic in nature as shown in FIG. 18. The remaining processing steps are identical to the processing steps described under FIGS. 1 through 6 and need not to be further detailed at this time.
It will now be clear that the process of the present invention is a significant advancement in the art of the manufacturing of semiconductor devices. Sub-micron gates can be fabricated in gallium arsenide and other semiconductor devices with a sufficient mass of metal in the gate electrode to reduce the resistance of the electrode to acceptable level. The process has a higher yield of successfully fabricating devices than do other techniques, and the T-gate electrodes are well suited to permit increased miniaturization of the devices.
Although the particular embodiment of the present invention has been described in detail for purposes of illustration, modifications may be made without departing from the spirit and scope of the present invention. Accordingly, the invention is not to be limited except as by the appended claims. | Disclosed is a method of fabricating a semiconductor field effect transistor, wherein the gate has a short foot portion in contact with the semiconductor substrate for a short gate length and consequent low capacitance, and a large amount of metal in a contact portion for low gate resistance. Salicides are formed on the T-gate source on drain contact areas resulting in large, low resistance contact areas. | 7 |
FIELD OF THE INVENTION
The present invention relates to rod-pumped oil wells. More specifically, the invention relates to rod guides that centralize sucker rods within tubing and scrape paraffin from the interior wall of tubing. A rod guide having a high erodible wear volume according to this invention has its by-pass area flow channels placed predominately in the non-erodible portion of the guide.
BACKGROUND OF THE INVENTION
As crude oil is depleted from an underground formation, pressure in the formation decreases to the point that oil must be pumped to the surface. One of several methods for removing crude oil from an underground formation employs a pumpjack located on the surface. The pump-jack is connected via a sucker rod string to a downhole pump at the bottom of the producing oil well. The sucker rod string comprises many sucker rods, each rod connected end-to-end to another rod by a coupling. The entire rod string extends down into a tubing string that is commonly contained within a well casing. The exterior well casing and internal tubing string are permanently installed after drilling the well. The tubing string serves as a conduit for the fluid produced, and the driving force for this production is transmitted to the downhole pump via the sucker rod string positioned within the interior of the tubing string.
The sucker rod string commonly reciprocates inside the tubing string as a result of the upward and downward motion of the pump-jack to which the rod string is fastened. Cyclical upward and downward motion of the pump-jack is thus communicated to a downhole pump located at the lower end of the tubing string. In response, the pump forces the produced fluids collected at the bottom of the well up the tubing string to the surface. In other applications, a progressing cavity (PC) pump is used at the bottom of the well, and in these applications power to the pump is transmitted via a rotating sucker rod string.
The production fluid in the tubing string typically acts as a lubricant for the sucker rod string. Lubrication is derived from the fluid because it is commonly a mixture which includes crude oil, along with water and natural gas. Typically also included in the production fluids are dissolved and undissolved salts, gases and other formation minerals, such as sand. The recovered crude oil is commonly stored in a tank near the well until it is removed for refining. Natural gas is removed in a pipeline. Water is usually reinjected into the production formation or in a disposal well in another formation close to the production formation.
Due to deflections of both the tubing and the rod string, contact may occur between these components. Even though the lubricating bath of the production fluid is present in the tubing, wear is incurred on the rod string and tubing when contact is made. The rod couplings typically have the largest outer diameter of the various components of the rod string and therefore incur, and cause, the most wear. Produced fluids that flow in the rod and tubing annulus also cause wear in the form of abrasion and corrosion. Through time, all these wear factors may lead to parting of the rod string or to the development of holes in the tubing.
When a hole develops in the tubing, pressure is lost inside the tubing. Production will then be pumped into the annulus between the tubing and the casing rather than to the surface for collection and storage. When a sucker rod separates, when a rod coupling breaks, or when holes are created in the tubing, the sucker rods and/or tubing must be pulled from the well and inspected in detail for the extent and nature of the damage. Damaged rods and tubing must be replaced. The resultant down-time as well as the workovers are a great expense to the well owners. Therefore, methods and apparatus for reducing or eliminating costs associated with lost production of hydrocarbons, equipment replacements and workovers are of great benefit to the well owners.
A well known method of preventing wear to the rods and tubing is the use of rod guides, also known as centralizers and paraffin scrapers. In cases involving a reciprocating rod string, paraffin scrapers may also serve as centralizers to reduce wear, in addition to their implied purpose of removing paraffin from the walls of the tubing. Rod guides have a greater outer diameter than other parts of the rod string. As such, the guides are sacrificial and protective. Rod guides retard rod and tubing wear by incurring most of the wear that does occur.
On the average, six rod guides are normally attached at various locations on each sucker rod in the rod string, but as many as ten or more locations per rod or as few as one location per rod may be used. As such, the guides act as a sacrificial and protective buffer between the rod string and the tubing. Wear occurs to the guide as it protects the rod string and the tubing and results in a reduction of the protective thickness of the guide over time.
The wearing effects suffered by the rod guides will eventually cause the guides to have an outer diameter which will approach and become similar to the diameter of the couplings or parts of the rod string larger than the shank or body of the sucker rod. When this happens, the guide will no longer buffer the contact between the rod string and the tubing. The rod guides must then be replaced.
The general state of the art may be gathered by reference to a Rod Guide/Centralizer/Scraper Catalog published in 1997 by Flow Control Equipment (FCE) Inc. This catalog discusses rod guide material selection, paraffin scrapers; classic rod guide designs such as the standard and slant blade; high performance designs such as the NETB, Stealth and Double Plus; rotating rod guides for PC pumps such as the Spin-Thru and the PC Plus; and field installed guides (FIG's) such as the Lotus twist-on, NEPG, Lotus Rubber and Guardian polyguides. Also relevant to the general state of the art are patents to rod rotators and stabilizing bars.
Many of the design considerations applicable to any rod guide for either rotating or reciprocating sucker rod strings are discussed in a 1993 publication by Charles Hart entitled "Development of Rod Guides for Progressing Cavity (PC) Pumps", a 1995 publication by Randall G. Ray entitled "Determination of Rod Guide Erodible Wear Volume," and a 1993 publication by Milton Hoff entitled "Hydraulic Drag Forces on Rod Strings." The general concept of erodible wear volume EWV and specific formulations as "gross" and "net" EWV are used herein in accordance with the use in these publications. In particular, the portion of a rod guide between the largest outer diameter on the rod string (typically the coupling diameter) and the inner diameter of the tubing string is the volume of the guide which can prevent damaging metal-to-metal contact. This protective volume of the rod guide is referred to as EWV. EWV is an important indicator of rod guide performance. The amount of the rod guide outside the outer diameter of the sucker rod couplings is in general referred to a Gross Erodible Wear Volume or Gross EWV. A more refined concept, which is known as Net Erodible Wear Volume, is that amount of the rod guide material that will erode before the sucker rod coupling contacts the tubing. Net EWV is always less than Gross EWV in conventional rod guide designs when the rod string is reciprocated to drive the downhole pump. Even a reciprocating rod string should be slowly rotated during reciprocation to maximize the useful life of the rod guides. An underlying assumption of both of these EWV definitions is that the rod string is continuously rotated and that the rod guides wear evenly. Also, both definitions are based on the assumption that the rod string is in tension and not in compression. In some rod guide designs, the Gross and Net EWV may be almost the same but as they approach equality, then fluid bypass area decreases and the flow resistance or drag around the guide increases to unacceptable levels. It is the primary objective of the invention presented herein to generate more efficient rod guide designs which have Gross EWV approximating Net EWV without sacrificing the necessary bypass area and geometry necessary to achieve desired levels of flow resistance or drag.
For clarity and ease of discussion, a rod guide may be considered to have a radially inner non-erodible zone and a radially outward erodible zone. The boundary line between the two zones, namely the erodible and the non-erodible zones, will be considered to be the projected circumference of the largest outer dimensions of any component anticipated to be on the rod string in the operative region where the respective rod guide is located, which typically will be the rod couplings above and below the respective rod guide. "Operative region" means that section of the rod string close enough to the rod guide so that it may be expected that the rod guide will furnish some protection to the rod and its couplings. It is meant to exclude for definitional purposes couplings or other rod string elements which may be several rod lengths away from the rod guide and which would have no effect on the function or performance of the rod guide, and thus no effect on the guide dimensions at issue. As used herein, the terms "by-pass" and "flow through" are intended to be synonymous and interchangeable.
U.S. Pat. Nos. 586,001 and 1,600,577 are directed to a cleaner for oil well tubing and a paraffin scraper, respectively. Both disclosures have a gross similarity to some of the embodiments of the present invention but differ in intent, function, material and design. The same may also be said of U.S. Pat. No. 2,153,787, which is directed to the shrink fitting of a guard by extraction of a plasticizer. A flexible guide is taught in U.S. Pat. No. 2,651,199. A method of on-site molding of scrapers is disclosed in U.S. Pat. No. 3,251,919.
U.S. Pat. Nos. 2,863,704 and 4,997,039 disclose a combination rod guide and sand purging device. Several of the embodiments referred to in the materials cited above are disclosed in U.S. Pat. Nos. 4,088,185, 5,115,863 and 5,277,254. Recently disclosed variations of a rod guide are found in U.S. Pat. Nos. 5,358,041 and 5,492,174.
None of the above references are directed to the concept of the present invention as set forth and described below. The present invention overcomes the deficiencies of the prior art and achieves its objectives by maximizing EWV while providing adequate flow through paths in and around the guide to both prevent excessive hydraulic drag during movement of the guide with respect to the produced fluid and avoid the creation of an excessive pressure drop as the guide passes through the produced fluid during the downward motion of the sucker rod string.
SUMMARY OF THE INVENTION
The present invention is directed to maximizing the EWV of the guide while at the same time providing for sufficient flow through and around the guide to achieve the necessary or desired low pressure drop for the particular operating conditions in which the rod guide is used. As will be developed further below, the concept of the present invention calls for maximizing the ratios of the EWV to the total volume (TV) of a rod guide as well as the EWV to the flow resistance or drag of a rod guide. Ideally one of the best designs would have a cross section that resembles a bicycle wheel with as few spokes as possible.
The present invention utilizes plastic injection molding technology to secure the rod guide to the sucker rod while also preferably obtaining the formation of the necessary flow passages and open areas in or around the rod guide without resorting to drilling or other subsequent mechanical processes to obtain the desired flow passages.
A suitable rod guide according to the invention is secured to a rod string which is then placed in the tubing, with the guide functioning to centralize the rod string in the tubing while it passes through the tubing to the downhole pump and thereby minimizes wear between the rod string and the tubing. The rod guide has a radially inner non-erodible zone available for flow through and a radially outer erodible zone, as defined above.
An object of the present invention is to maximize the erodible wear volume of a rod guide while maintaining adequate flow through and around the guide to obtain a desired low pressure drop or drag across the guide.
It is an object of the present invention to provide an improved centralizing device which overcomes the deficiencies of the prior art between Gross and Net EWV and at the same time provides for high erodible wear volume consistent with the desired high flow through and low drag characteristics.
It is a feature of the present invention to provide for the molding of centralizers on the rod without having to resort to a drilling or similar operation to produce fluid flow paths in the molded guides resulting in the desired flow through for the guide with a high erodible wear volume.
It is a feature of the present invention to provide an improved and low cost rod guide which averts contact between the sucker rod string and the tubing of a producing oil well.
It is a further feature of the present invention to provide an improved rod guide that may clean mineral scale and paraffin deposits from the interior surface of the tubing when the guide is fixed to a reciprocating rod string.
It is another feature of this invention to achieve the above two features with a provision of an EWV which approaches the maximum obtainable in terms of Gros and Net EWV while providing a desired high flow through and low drag characteristics when the rod guide is in a typical application.
Still another feature of the invention is a rod guide molded around a rod intended to be placed within the tubing, with the rod guide having a high EWV and flow channels or by-pass areas predominately located in the non-erodible zone of the rod guide.
A significant advantage of the present invention is that the rod guide may achieve the above objects and features while the guide remains sturdy, compact, durable, simple, ecologically compatible, reliable, and inexpensive and easy to manufacture and maintain.
Other objects, features and advantages of the present invention, as well as a fuller understanding of this invention, may be had by referring to the following description and claims taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to facilitate the understanding of the present invention, reference will now be made to the appended drawings of preferred embodiments of the present invention. The drawings should not be construed as limiting the invention, but are exemplary only.
FIG. 1 is a side view of a typical well having a reciprocating rod string provided with rod guides of the present invention.
FIG. 2 is a side view of one embodiment of a rod guide of the present invention.
FIG. 3 is a top or end view of the rod guide shown in FIG. 2.
FIG. 4 is an isometric view of the molds for the moving and stationary platens of a molding system used to mold the present invention on a rod. The front right of each side mold supports the cavity rods in a cantilevered fashion. These rods are withdrawn before the mold is opened. The upper side mold is mounted to the stationary platen and is shown positioned adjacent the rod for a molding operation. The lower side mold is mounted on the moving platen and away from the rod. In this view, the moving platen is retracted and the molds are in the open position. The cavity rods are shown partially inserted for clarity.
FIG. 5 is an isometric view of the molding apparatus in accordance with the present invention after the separation of the mold from the rod following the molding of a guide on the rod.
FIG. 6 is another embodiment of the present invention with an enlarged flow through area creating a rod guide having a generally Maltese cross configuration which can be achieved by changing the configuration and cross-section of the cavity rods.
FIG. 7 is an end or top view of another embodiment of the present invention in which the rod guide has expanded internal flow through cavities as well as external flow channels, both of which can be obtained by changing the configuration and cross-section of the cavity rods and mold geometry.
FIG. 8 is an end or top view of yet another embodiment of a rod guide in accordance with the present invention in which the generally Maltese cross shaped blades are provided with flow through cavities. The outer surface of the guide is off-set at its center of curvature from the rod center to provide an outer surface conforming to the internal curvature of the tubing. In all cases, the outside diameter of the guide is only slightly less than the inside diameter of the tubing.
FIG. 9 is a side cross-sectional view of an embodiment of a rod guide in accordance with the present invention in which the outermost portions of the guide extend longitudinally parallel to the axis of the rod string and in excess of the portion of the guide molded to and in contact with the rod.
FIG. 10 is a top or end view of another embodiment of a rod guide of the present invention in which the space between the support arms of the rod guide has been enlarged to provide additional flow through capacity.
FIG. 11 is an end or top view of an embodiment of the present invention in which four or more of the two bladed rod guides have been molded on the rod, with each successive guide indexed 45 degrees with respect to the next adjacent rod guide in a nesting approach to concentrate the EWV, which is undesirably low for a single two bladed guide alone but increasingly effective as more two bladed guides are indexed and molded closely together.
FIG. 12 is a side view of a portion of the array shown in FIG. 11, illustrates only two of the two blade rod guides indexed at 90°.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is perhaps best understood by reviewing the first principles upon which the invention is based. As has been noted above, it is desired to maximize the EWV relative to the TV of a rod guide and simultaneously, at least to the extent desired or necessary, maximize the fluid flow channels through and/or around the rod guide to minimize the adverse affects of drag, turbulence or pressure drop across the guide.
The maximum EWV may be obtained by filling the entire area between the rod coupling outside diameter and the inner surface of the tubing with rod guide material like the rim on a bicycle wheel. By maintaining complete circumferential outer contact of the guide with the tubing inside diameter and also providing flow through the guide in the area between the outer diameter of the rod coupling and the outer diameter of the sucker rod should fluid flow through the guide is provided and erodible wear volume is maximized. As additional flow through holes in the guide are provided, usually in the preferred embodiments in a symmetrical pattern, flow is increased to the desired level with a desired low pressure drop and without decreasing the EWV. Preferably at least three through holes are thus provided in the guide. However, the structural integrity of the rod guide is reduced in the process. The present invention balances these factors in a unique manner to provide a moldable rod guide with a high EWV, a desired structural integrity, and flow through the guide to achieve a low pressure drop or low drag.
As holes in the rod guide are enlarged, a Maltese cross configuration such as shown in FIG. 6 may be formed by support arms which interconnect a radially inner substantially sleeve-shaped portion in gripping engagement with the rod with a radially outward sleeve-shaped portion forming a cylindrical outer surface of the rod guide essentially equal to the inside diameter of the tubing. The outer surface may be separated, as shown in FIG. 8 or FIG. 10, to reduce the EWV and provide for greater flow through capacity. Additional flow through capacity (by-pass area) may thus be obtained by increasing the flow through area in the erodible zone of the rod guide. Ideally, the erodible zone of the rod guide is maximized while still providing for high flow through capacity, and the resulting design has a sufficient structural integrity for a molded rod guide. To obtain these objectives, the relatively simple rod guide molding process becomes more complicated. A related concept involves the longitudinal expansion of the radially outer portions of the rod guide as shown in FIG. 9 and will be discussed in greater detail below.
Referring to FIG. 1, a pumping apparatus 100 is shown for pumping fluids from a well 102 and through a string of tubing 106 disposed within well casing 108. Connected to the pumping apparatus 100 is a string of sucker rods 105 connected by coupling, such as typical coupling and pin connector means 104. The pumping apparatus as shown in FIG. 1 drives the rod string in a reciprocating manner to pump fluid to the surface through the well tubing. The rod string 105 may be rotated by a rod rotator 114, if desired, to distribute wear more evenly to both the rod guides 107 and the sucker rods 105.
When the pumping apparatus 100 is on the down stroke of its reciprocating action, the string of rods 105 move axially within the tubing 106 to operate the downhole pump (not shown). A plurality of rod guides 107 of the present invention are fixedly engaged around the sucker rods 105 at selected locations throughout the length of the rod string 105. During this reciprocating movement of the string of sucker rods 105, the well fluids are caused to flow upwardly in the tubing 106 on the upstroke and the rod guides 107 fall through the fluid on the downstroke.
FIG. 2 shows a rod guide 200 molded to a rod 202. The generally cylindrical rod guide body 204 has a circumferential outer surface 210 and is provided with a plurality of cylindrical holes 206 which end at the top and bottom surfaces 208 and 209 of the rod guide, respectively. As a result of the formation of the holes by cantilevered cavity rods as discussed subsequently, the holes 206 may have excess nipple material 212 at one end, as will be made more apparent by considering the molding process described below. This excess material 212 is shown exaggerated in FIG. 2 for clarity.
When seen from a top or end view, the holes 206 appear as holes 306 in FIG. 3 wherein the rod guide 300 is molded about rod 302 and has an outer circumferential surface 304 sized for initial contact (or approximately so) with the internal surface with the tubing (not shown). The outer surface of the couplings in the operative region of the rod 302 is shown in dashed lines and represents the circumferential boundary 308 which defines the inner limit of the erodible wear volume (EWV) 310 which extends to the outer surface 304. The area between the boundary line 308 and the rod 302 thus defines the non-erodible zone of the rod guide. In general, the rod guide may consist of a radially inner non-erodible zone and a radially outward erodible zone. As noted above, the boundary line between the two zones, the erodible and the non-erodible zone, is the projected circumference of the largest outer dimension of any component anticipated to be on the rod string in the operative region of the rod guide. The boundary line which in this example is equal to the outside diameter of the nearest rod coupling is thus the dashed line 308 shown in FIG. 3. The erodible zone contains that material in the region between the boundary line 308 and the outer surface of the rod guide 304 which is only slightly less than the inner diameter of the tubing string. The erodible zone includes that volume of material in the rod guide which may be eroded in use before a component on the rod in the operative region of the rod guide contacts the tubing. It is desired for the rod guide to have the maximum amount of material in the erodible zone and thereby to have the maximum EWV for a given length of guide. At the same time, it is desired to provide for adequate flow through capacity (by-pass area) through the rod guide by providing flow channels, holes 306, through the rod guide. These holes will preferably be located predominately in the non-erodible zone of the rod guide.
As the size of the flow through holes is enlarged to provide for a greater volume of fluid flow through the rod guide without increasing drag and pressure drop, a configuration such as shown in FIG. 6 may result, wherein a rod guide 600 is molded on rod 602. The guide 600 is held in place on the rod by a radially inner substantially cylindrically shaped portion 604 of the non-erodible zone which surrounds the rod 602 and in gripping engagement therewith as a result of the molding process. The enlarged flow through holes 610 form a plurality of support arms 606 in the form of a Maltese cross which connect the radially inner portion 604 with a radially outer cylindrical surface 608 of the crodible zone for complete circumferential contact with the tubing (not shown).
As shown in FIG. 7, a rod guide 700 has support arms which include indentations defined by 704 and erodible wear surfaces 702. Flow through cavities 706 are spaced circumferentially about rod 710, and additional flow capacity is provided by the circumferential spacing between the indentations 704. A similar expansion of the flow through area may result in a Maltese cross of the form as shown in FIG. 8, in which a rod guide 800 has an expanded flow through area bounded by surfaces 804 and flow through holes 806. The outer linear surface 802 has a diameter slightly smaller than the inside diameter of the tubing (not shown). The center 808 of the curved outer surface 802 coincides substantially with the center 110 of the sucker rod 812.
In FIG. 10, a rod guide 1000 is molded about rod 1002 and has flow through areas bounded by 1004 and 1006 which form EWV 1008 bounded on the outside by wear surface 1010. Support arm extensions 1012 may substantially touch to form a substantially complete circumference of wear surface of the EWV to contact the tubing.
The molding operations according to the present invention may be of the type described below in connection with FIGS. 4 and 5. The details of injection molding as employed in the art are well known and, except as expressly noted herein, do not constitute a part of the present invention. A description of the operation and construction of injection molding equipment may be found in a 1962 publication Manufacturing Processes by S.E. Ursunoff, American Technical Society, beginning at page 56. A description of the application of molding processes in connection with molded plastic rod guides, centralizers, scrapers and the like may also be found in U.S. Pat. Nos. 3,251,919 and 4,088,185.
Among the materials suitable for use in accordance with the present invention are polyphenylene sulfide, polyphthalamide, polyamide (nylon), polyethylene, polypropylene, polycarbonate and polyester. All these thermoplastic resins may also be used with glass, arimide fibers and mineral fillers. Ultra-high molecular weight polyethylene may be employed in circumstances which do not involve injection molding. In general, plastics having suitable shrinkage properties and tensile strengths may be employed if not too brittle on molding, if their abrasion and wear characteristics are satisfactory, and if they can withstand the wide range of tempera tures an d c orrosive conditions found in oil well operations. A more extensive listing of suitable materials may be found in U.S. Pat. No. 4,088,185.
It is desirable but not essential according to the present invention to provide the flow through holes in the rod guide without resort to drilling or similar means. The present invention includes the process herein describe of providing such flow through holes as a part of the molding process. As shown in FIG. 4, a two part mold 400 is created or provided consisting of left-side and right-side molds 402 and 404 with a suitably shaped rod guide cavity consisting of left-side and right-side portions 444 and 410, respectively. The cavity in each half of the mold may be filled with plastic material 408 injected into the mold through tube 406. Cantilevered within the cavity may be one or more rods, such as, for example, rods 412 , 414 , 440 and 458 . Th ese rods may each b e cantilevered in the mold cavity 410 and supported by one end of a respective supporting end block member 418. Each mold half also includes an axially opposing end block member 416. The connection face between the rods 412 an d 414 with the mold half 404 i s shown as 462 and 46 4 in FIG. 4.
The two mold halves 402 and 404 are radially closed about the sucker rod 446 and the end blocks 418 are moved axially with respect to mold portions 402 and 404 to a closed or mold position to provide a totally enclosed cavity into which the plastic material 408 is injected through tubing 406. Each mold half includes end blocks with substantially semi-circular ports 424 the rein for receiving the sucker rod 446 when the mold halves are closed. A suitable face seal 428 is provided on the radially inward face of one or both blocks 416, 418 for sealing with the radially opposing block when the mold is closed. Similarly, a seal 430 is provided for sealing e ngagement between the end blocks 418 and the r espective primary left side and right side mold 402 and 404 when the mold is closed. The cantilevered rods 412, 414, 440 and 458, w hich may be of any of many shapes to provide flow through holes of the shape or shapes desired, are further supported in the closed position by insertion of the free or cant levered end of each rod into shallow pockets 420, 422, 432, 434 in the respective opposing end blocks 416 of mold ports 402 and 404 to support the free ends of the rods.
As shown in FIG. 5, after the plastic material 518 has been injected through conduit 520 and through the port 522 in the mold half 516 and into the rod guide cavity 524 formed by the mold halves 515 and 516 which makes up the mold 500, a rod guide 502 having a desired EWV and outer surface 506 will have been formed about rod 508. Rod guide 502 contains axially extending flow through holes 504 formed by the cantilevered rod members 412, 414, 440 and 458. Also, a plurality of outer flow paths 505 are formed about the outer periphery of the guide 502, with these axially extending flow paths 505 being formed by the respective generally semi-cylindrical radially inwardly projections 526 provided in each mold half 514 and 516. The end blocks 509 and 510 are moved longitudinally along the axis of the rod 508, thereby breaking the seals 530 and removing the rods from the holes 504. When end blocks 509 and 510 carrying cantilevered rods 412, 414, 440 and 458 are clear of the guide 502, the mold halves which are attached to the moving and stationary platens of the injection molding machine may then be separated. The substantially sideways U-shaped seal 532 comprising end seal 534 and top and bottom legs 536 and 538 will thus be broken during this separation process. Similarly, the face 521 on the end block 510 may be radially separated from the opposing face on the block 509. In this manner, flow through holes 504 of any desired shape or size may be provided in a single molding operation. The rods 512, 514, 540 and 558 are cantilevered and fixed to end blocks 509 and 510 and sufficient spacing is provided during the molding operation for the blocks 509 and 510 with their supported rods to clear the molded work piece formed on the sucker rod 508. In the above fashion, it is possible to provide flow through holes in various pieces of any molded guide in any size or shape.
In operation, the mold halves and end blocks are closed about the rod and the plastic material is injection molded around the rod. After the guide is formed, the end blocks with cantilevered rods are moved longitudinally along the axis of the rod until clear of the molded workpiece. The major mold halves may then be opened (moved radially with respect to the rod 508) and separated from the molded guide. Those skilled in the art will appreciate that the sucker rods 408 on which the rod guides are molded conventionally have threaded end members 507 as shown in FIG. 5. During the rod guide molding process, these threaded connections 507 are normally broken and the rod guides are molded at preselected axial locations along the length of a single sucker rod. After the rod guide molding operation, the connections 507 on the rods 508 may be threadedly coupled to comprise a rod guide string which is reciprocated in the well.
In a similar fashion to that described above, the dog bone configuration of the centralizer or guide 1100 of FIG. 11 may be molded about rod 1102. Such guides 1100 may be indexed with respect to each other as shown in FIG. 11 to form a nest of rod guides or a helical array of guides effectively providing complete 360 degree coverage and wear contact area with the tubing. As shown in FIG. 11, guides 1100 may be molded about rod 1102 in an indexed fashion of, for example, 45 degrees from the next adjacent guide. The flared area 1104, 1108, etc. may be as extensive as desired consistent with the needed flow through characteristics to provide the desired wear surface and EWV. Holes for the desired flow through 1106 and 1110 may be provided by the molding techniques described herein.
Two of the indexed guides of FIG. 11 are shown in FIG. 12 wherein the array 1200 of guides 1204, and 1208 with the wear surfaces as described above are molded about rod 1202 in an indexed manner of 90 degrees with respect to the next adjacent guide. If desired, flow through holes 1206 and 1210 may be provided by means of the molding process described above.
As shown in FIG. 9, these same techniques may also be applied to mold a guide such as 900 around rod 902 with material in contact with the rod 908 and gripping the rod. The rod guide includes extended longitudinal wings 906 to provide extended wear surface 904 and extended EWV. A multiplicity of flow through holes 910 and 912, for example, may be provided to permit the necessary and desired flow through capacity. The extended longitudinal wings are a further example of a fundamental concept of the present invention in that such a configuration inherently provides for extra outer material for EWV relating to the total volume of the guide and still maintain the necessary flow through capacity in the non-erodible zone of the rod guide.
In most if not all of the configurations shown herein, the circumferential extent of any of the separated arms of the rod guide may be expanded to any extent desired consistent with the desired flow through characteristics or the need for by-pass area up to and including full circumferential contact with the tubing.
While it is preferred to form the flow through channels as described herein, it is within the scope of the claims below describing the present invention to drill some or all of the holes, if desired. The cantilevered rods referred to above may also be suspended by other material supports within the mold cavity.
Further embodiments such as the use of a spiral or helical vane may be employed in accordance with the present invention. In such an embodiment, the EWV may be controlled as a function of the pitch and number of leads provided. The flow through capacity may be controlled by the number and position of the holes in the erodible and the non-erodible zones of the rod guide.
It will be apparent to one of ordinary skill in the art that the present invention may be modified to employ the principles taught within the scope of the present invention. Various changes and modifications may be effected in the illustrated embodiment of the present invention without departing from the scope and spirit of the invention defined in the appended claims. The embodiments shown and described above are exemplary. Various modifications can be made in the construction, material, arrangement, and operation, and still be within the scope of the invention. The limits of the invention and the bounds of the patent protection are measured by and defined in the following claims. | A rod guide fixedly molded around the shank of a sucker rod string with the rod guide including a radially inner non-erodible zone and a radially outer erodible zone. The non-erodible zone includes a radially inner substantially sleeve-shaped portion having an inner cylindrical surface for gripping engagement with the rod. A plurality of flow through channels are spaced outward of the substantially sleeve-shaped portion. Each flow through channel extends axially along the rod guide and has a maximum circumferential width greater than any gap in the radially outer surface of the erodible zone circumferentially aligned with and radially outward of the respective flow through channel. The radially outer surface of the erodible zone may have a cylindrical outer configuration, such that a radially outward substantially sleeve-shaped portion is provided for engagement with the tubing. The upper and lower surfaces of the rod guide may each be inclined such that the radially outer surface of the rod guide extends longitudinally in excess of the inner cylindrical surface of the sleeve-shaped portion and in engagement with the rod. A guided sucker rod includes an elongate rod having threaded end connectors for mating engagement with an adjoining sucker rod and one or more rod guides fixedly molded thereon. According to the method of the invention, left-side and right-side molds are created each including one or more elongate cavity creating member supported in a cantilevered fashion from a supporting end block. A plastic material is injected into the mold cavity, and the supporting end block is then moved longitudinally along the axis of the rod to remove the one or more channel performing members from the molded rod guide. | 4 |
RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 60/474,861, filed May 30, 2003, entitled, “Radial Reflection Diffraction Tomography,” which is incorporated herein by this reference.
The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to imaging, and more particularly to an imaging method and apparatus employing Radial Reflection Diffraction Tomography.
2. Description of Related Art
Intravascular ultrasound (IVUS) imaging provides a method for imaging the interior of blood vessel walls. In standard acoustical techniques, a catheter with a rotating ultrasound transducer is inserted into a blood vessel. The transducer launches a pulse and collects the reflected signals from the surrounding tissue. Conventional ultrasonic imaging systems use B-mode tomography or B-scans, wherein images are formed from the envelope of the received display echoes returning to an ultrasonic transducer as brightness levels proportional to the echo amplitude and by assuming straight ray theory (i.e., geometrical optics). The brightness levels can then be used to create cross-sectional images of the object in the plane perpendicular to the transducer image. However, such images typically suffer from the consequences of ray theory of sound propagation, which does not model its wave nature.
A circumferential scan can be made by either rotating a single transducer (mechanical beam steering) or by phasing an array of transducers around a circumference (electronic beam forming). Typically, one ultrasound pulse is transmitted and all echoes from the surface to the deepest range are recorded before the ultrasound beam moves on to the next scan line position where pulse transmission and echo recording are repeated. When utilizing B-scan, the vertical position, which provides depth of each bright dot is determined by the time delay from pulse transmission to return of the corresponding echo, and the horizontal position by the location of the receiving transducer element.
Although B-scan IVUS images can be utilized to detect plaque and characterize its volume, the classification of plaque types by ultrasound is very difficult. Conventional B-scan images utilizes scattering, which, in turn, depends on the acoustic impedance dissimilarity of tissue types and structures. Although hard calcifications in some plaque can be detected using such a mismatch, the similarity in the acoustic properties of fibrous plaque and lipid pools prevents direct identification. Consequently, the size of the fibrous cap cannot be accurately estimated.
Diffraction tomography has additionally been applied to medical imaging problems for a number of years, usually in a standard circumferential through transmission mode. Furthermore, improved vascular images have been provided by utilizing time domain diffraction tomography, a technique capable of accounting for the wave propagation of the transmitted acoustic waves in addition to redundant information from multiple angular views of the objects imaged. A related B-mode approach that incorporates spatial compounding has also been employed to provide improved vascular images through multiple look angles.
Background information on rotational IVUS systems are described, for example, in U.S. Pat. No. 6,221,015 to Yock. Background information on phased-array IVUS systems are described, for example, in U.S. Pat. No. 6,283,920 to Eberle et al., as well as U.S. Pat. No. 6,283,921 to Nix et al. Multi-functional devices have been proposed in other areas of vascular intervention. For example, U.S. Pat. No. 5,906,580 to Kline-Schoder et al., describes an ultrasound transducer array that may transmit signals at multiple frequencies and may be used for both ultrasound imaging and ultrasound therapy. Therapeutic ultrasound catheters, are described, for example, in U.S. Pat. No. 5,725,494 to Brisken et al. and U.S. Pat. No. 5,581,144 to Corl et al., which describes another ultrasound transducer array that is capable of operating at multiple frequencies. However, none of the above devices and associated techniques from the above cited patents, are suited for rapid identification of objects, such as, but not limited to, vulnerable plaque or objects recessed in a bore hole, in accordance with the principles of the present invention.
SUMMARY OF THE INVENTION
The present invention is directed to a wave-based imaging method, which includes: directing predetermined energy waves radially outward from within an interspace and receiving scattered energy waves from one or more objects. The received data are processed to produce images of the objects, wherein the processing includes application of a wave-based algorithm that can map an angular location and a plurality of frequency parameters of the received scattered energy waves to construct images of the one or more objects.
Another aspect of the present invention is directed to a wave-based imaging method that can be utilized to characterize a plaque, which includes: inserting a catheter having a longitudinal axis and a distal end into an artery, wherein the catheter further includes a single transmitter disposed about the distal end of the catheter and a receiver aperture having a plurality of receivers additionally disposed about the distal end of the catheter, wherein the transmitter and the receiver aperture is capable of rotating up to 360 degrees about the longitudinal axis of the catheter. As part of the method, one or more predetermined energy waves are directed radially outward from the single transmitter and radial scattered energy waves are received in a predetermined imaging mode by the receiver aperture. The received scattered energy waves results in collected data capable of being processed to produce images of plaque from the surrounding artery walls, wherein the processing includes application of a wave-based algorithm that can map an angular location and a plurality of frequency parameters of the received scattered energy waves to construct the images and determine the risk of rupture and/or thrombosis.
Another aspect of the present invention is directed to a wave-based imaging method that can be utilized to characterize a plaque, which includes: inserting a catheter into an artery, directing one or more predetermined energy waves radially outward and receiving one or more radial scattered energy waves from a distal end of the catheter; collecting a radial scattered tomographic data baseline of the artery's tissue; measuring an applied external pressure to the artery; obtaining a deformation radial scattered tomographic data set of the artery's tissue after application of the external pressure; and processing the radial scattered tomographic data baseline and the deformation radial scattered tomographic data set to produce a final image indicating elasticity of the artery to characterize the imaged plaque, wherein the processing includes application of a wave-based algorithm that can map an angular location and a plurality of frequency parameters of the received scattered energy waves.
A further aspect of the present invention is directed to a wave-based imaging apparatus, which includes a flexible substrate having a longitudinal axis and a distal region and one or more elements disposed on the distal region and capable of directing one or more predetermined energy waves radially outward and receiving one or more radial scattered energy waves from one or more objects. The received scattered energy waves are capable of producing images of one or more objects by processing a collected data set, wherein the processing includes application of a wave-based algorithm that can map an angular location and a plurality of frequency parameters of the received scattered energy waves.
A final aspect of the present invention is directed to a wave-based imaging apparatus that includes a Hilbert space inverse wave (HSIW) algorithm that can map an angular location and a plurality of frequency parameters of said received reflected diffracted energy waves so as to characterize plaque within a living vessel.
Accordingly, the present system and method employs desired Radial Reflection Diffraction Tomographic techniques to determine the state and location of buried wastes, to track plumes of underground contaminants of materials, to determine the state of materials residing in waste drum barrels or weapons, to evaluate nondestructively parts having existing access holes (e.g., automobile parts), and for identifying potentially life threatening vulnerable plaque buildup on living vessel walls.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a illustrates a basic multimonostatic mode configuration that includes a single transducer rotating about a fixed center.
FIG. 1 b illustrates a basic multistatic mode configuration that includes a fixed annular array of outwardly directed transducers.
FIG. 1 c illustrates a basic multistatic mode configuration that includes a rotating aperture.
FIG. 2 shows a conventional IVUS catheter.
FIG. 3 a shows a conventional IVUS catheter inserted into a diseased artery.
FIG. 3 b illustrates the RRDT geometry of the present invention when a catheter is inserted into a diseased artery.
FIG. 4 illustrates RRDT non-destructive evaluation within a bore hole.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the following detailed information, and to incorporated materials; a detailed description of the invention, including specific embodiments, is presented.
Unless otherwise indicated, numbers expressing quantities of ingredients, constituents, reaction conditions and so forth used in the specification and claims are to be understood as being modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the subject matter presented herein. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the subject matter presented herein are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
General Description
The present invention employs inverse wave techniques to reconstruct images of a medium surrounding a physical probe in a plane perpendicular to an axis of rotation in a radial reflection configuration, i.e., in a multimonostatic or a multistatic arrangement disclosed infra, wherein one or more transmitting and receiving elements, more often at least about 15 of such elements, e.g., transducer(s), are at a fixed radius and designed to collect scattered fields, e.g., reflected and diffracted fields. Such a radial reflection diffraction tomography (RRDT) technique is based upon a linearized scattering model to form images given the disclosed physical transmitter and receiver configurations and the mathematical method, i.e., a Hilbert-based wave algorithm, utilized to invert the scattering collected fields.
As example embodiments, the multimonostatic and multistatic probes can be mounted at the end of a flexible substrate, such as a catheter or snaking tube that can be inserted into a part with an existing access hole or a medium (e.g., an artery) with the purpose of forming images of the plane perpendicular to the axis of rotation. By applying the Hilbert space inverse wave (HSIW) algorithm of the present invention to the collected data of such multimonostatic and multistatic probes, radial reflected diffraction tomographic images are readily obtained.
Specific Description
FIG. 1( a ) shows a basic multimonostatic conceptual arrangement of the present invention, wherein a single energy source element 1 , such as a transducer, can operate as both source and receiver (as denoted by T/R, to indicate transmitter and receiver) at multiple spatial locations. At each angular location along the illustrated dashed circumference, as denoted by the directional arrow, energy source element 1 can launch a primary field wave (not shown) and receive a reflected scattered field wave (not shown). Such an arrangement often requires a spectrally wide band frequency diverse source capable of producing frequencies from about 1 kHz to about 3 THz (Electromagnetic frequencies), often from about 100 Hz to about 10 GHz (Acoustic frequencies), more often between about 20 MHz and about 60 MHz (Acoustic frequencies), to provide spatial diversity so as to form images of a surrounding medium.
FIG. 1( b ) shows an example conceptual multistatic mode embodiment, wherein a plurality of fixed energy source elements 2 , e.g., transducers, are arranged as an annular array, generally designated by the reference numeral 20 . In succession, along for example, the illustrated directional arrow, each energy source element (for example, the element denoted by the letter T to indicate a transmitter) is capable of launching a primary field wave (not shown) and a backscattered field wave (not shown) is measured on all the remaining elements (as denoted by the letter R, indicating the remaining fixed elements are operating as receivers).
FIG. 1( c ) illustrates a beneficial multistatic conceptual arrangement that includes a plurality of energy source elements 4 configured in a rotating sub-aperture 6 , as denoted by the bi-directional arrow, formed by a single transmitter, as denoted by the letter T to indicate a transmitter, and surrounded by multiple receivers, as denoted by the letter R. At each angular location, as denoted by the single directional arrow along the illustrated dashed circumference, transmitter T can launch a primary field (not shown) and a backscattered field (not shown) is measured on all receivers R.
When operating in a reflection mode as disclosed herein, the mathematics applied to the collected data operate beneficially to image objects because the range resolution of the reconstructed image is proportional to the number of frequencies used in the reconstruction. Under the Hilbert space inverse wave algorithm, increasing the number of frequencies and transducers, increases the complexity of the reconstruction, the size of the intermediary data files, reconstruction time, and computer memory requirement. Thus, the trade-off between computer resources and resolution is a consideration. Nonetheless, the techniques employed in the present invention are beneficial even at acoustic frequencies from as low as about 100 Hz to as high as about 10 GHz. Such lower frequencies allow the disclosed embodiments to additionally be employed in borehole type of applications, such as, but not limited to, characterizing underground contamination plumes or waste in contamination barrels.
For either the multimonostatic or multistatic example embodiments, the planar reconstruction of the imaged object(s) requires that the one or more collected measurements map a pair of spatial variables (i.e., angular location and incident source frequency) of a physical object into the angular location and frequency parameters of the measured field.
An exemplary application of the present invention is in the characterization of vulnerable atherosclerotic plaque. Arthrosclerosis is a condition where the arteries are obstructed by the buildup of deposits, “intravascular plaque” (IVP), on the inside of arterial walls and such a buildup of deposits can lead to what is known to those of ordinary skill in the art as cerebrovascular disease, which is the third leading cause of death and the leading cause of major disability among adults. Plaque grows as a fibrous tissue encapsulating a lipid pool and as the plaque grow it may incorporate calcium. Of particular concern is vulnerable or unstable plaque because of the possibility of such plaque becoming inflamed and unexpectedly rupturing. Stable or non-vulnerable plaque, typically includes a thick layer of fibrous tissue of about 800 microns but is not life threatening and can be treated slowly. A thin fibrous cap of typically up to about 300 microns covering a pool of a soft lipid core typically characterizes vulnerable plaque. When such a cap is disrupted, the thin cap is compromised and the lipid deposited into the artery can produce adverse effects, such as thrombus formation, strokes and death.
FIG. 2 shows a conventional catheter, generally designated as reference numeral 200 , for intravascular tissue characterization, such as atherosclerotic vulnerable plaque. Such a catheter 200 , typically has an elongated flexible substrate 202 with an axially extending lumen 204 through which a guide wire 206 , and/or various other devices or other instruments can be delivered to a region of interest. An ultrasonic transducer assembly 208 is provided at the distal end 210 of the catheter, with a connector 214 located at the proximal end of the catheter for transducer manipulation and processing received transducer signals. Transducer assembly 208 can comprise a plurality of transducer elements 216 arranged in a cylindrical array centered about a longitudinal axis 218 of the catheter for transmitting and receiving ultrasonic energy. Adhesive (not shown) and or an end-cap (not shown) can be applied to transducer assembly 208 , and lumen 204 to protect such elements from the surrounding environment. Transducer assembly's 208 individual elements (not shown) and conductive acoustical backing (not shown) are often mounted on the inner wall of elongated flexible body 202 operating as the flexible substrate.
FIG. 3 a illustrates a typical IVUS method using such a catheter 200 , as shown in FIG. 2 a . In such a conventional application, catheter 200 , having a transducer assembly 208 that can launch an energy wave as a primary field (as denoted by the letter F) is inserted typically non-centered into a nominally circular diseased artery 302 . Around a wall 304 of artery 302 is a fibrous collagen plaque 306 . A lipid pool 308 can reside inside such a fibrous structure, wherein when a fibrous cap 310 of plaque 306 separating lipid pool 302 from the blood (not shown) within artery 302 is more than about 800 μm thick, plaque 306 is characterized as stable. However, in cases where cap 310 is less than about 300 μm thick, such a plaque is characterized as vulnerable, and is more likely to rupture and/or thrombosis.
The present invention utilizes the disclosed RRDT approach for improved intravascular applications such as characterizing plaque as discussed above, and incorporates various aspects of the method of utilizing a probe, such as, but not limited to, the catheter as shown in FIG. 3 a . However, such catheters 200 and similar probes known to those of ordinary skill in the art typically show angular overlap for beam processing, which results in loss of valuable image information of one or more objects of interest within a surrounding medium. The present invention overcomes such processing by incorporating novel improvements of the transmitters and receivers, by utilizing frequencies between about 20 MHz (Acoustic) and about 60 MHz (Acoustic), and by utilizing RRDT techniques of the present invention as discussed herein. Such novel embodiments accounts for phase, amplitude, and beam diffraction, to recover not only such loss of valuable image information information but to further enhance the imaging capabilities of the invention by providing images with improved lateral resolution of the acoustic absorption and sound speed.
FIG. 3 b shows the geometry incorporated by the RRDT method of the present invention. FIG. 3 b shows a cross-sectional view of a catheter 200 , having an outer diameter between about 0.25 mm and about 5 mm, being inserted into an artery 302 , having a surrounding plaque 306 that includes a cap 310 and a lipid pool 308 . Inserted into artery 302 is a non-centered catheter 200 , which includes a transducer assembly (not shown) that can be disposed about the distal end of catheter 200 , as disclosed in the present invention, with a radial location specified by r O ≡R O (cos θ O , sin θ O ), where R O is the catheter 200 probe radius, a constant. At each angular location, θ O , transducer assembly 208 , as shown in FIG. 3 a , launches a primary field F radially outward (as denoted by the letter r) into a medium, such as the blood (not shown) and surrounding tissue in this example, and the transducer arrangement, as disclosed in the present invention, can measure a reflected scattered field (not shown) having, for example, at least up to about 90 degrees of angular content from one or more objects, such as the linings of cap 310 that overlies lipid pool 308 .
As another example embodiment, the RRDT method and apparatus of the present invention can be combined with elastography to gain further insight into a surrounding medium's elastic properties and provide further information in the determination of characterizing plaque as vulnerable or stable. Generally, the contrast in elastic properties between a lipid pool and a fibrous cap is evident. By utilizing elastography, the elastic properties of a vessel wall can be obtained by observing a deformation of the vessel due to an external pressure, such as the pressure produced by a heart. Such a change in the arterial pressure due to the pumping action of the heart produces a measurable deformation of the tissue surrounding the vessel. Such a deformation can be measured by tracking a motion of patterns in successive intravascular scans as disclosed by the present invention. By knowing the arterial pressure and the measured deformation, the present invention can recover elastic properties of the surrounding tissue. From such elastic properties, one can further characterize the surrounding tissue to predict plaque composition.
FIG. 4 illustrates a further beneficial embodiment, wherein the present invention can be utilized for non-destructive characterization (i.e., RRDT imaging) in applications other than for intravascular RRDT imaging. As shown by the example cross-sectional underground view of a borehole 404 in FIG. 4 , a flexible substrate 400 or snake-like tube having a transducer assembly 402 similarly configured like the intravascular RRDT application discussed above, can be lowered into bore hole 404 so as to image a site using RRDT techniques. Such an arrangement can launch a primary field (denoted by the letter F) and receive diffracted energy waves having frequencies often between about 100 Hz and about 300 Hz, to determine the state of buried wastes, such as waste within a radioactive waste drum barrel 410 or a biohazardous container, and/or to track a plume 412 of underground contaminants. In a similar manner, disclosed probes herein, can be inserted into waste drum barrels 410 , or weapons (not shown) or any part having an existing access hole, such as, but not limited to, an automobile engine, and determine the state of the part or material.
Hilbert Space Wave Inversion
Hilbert spaces are spaces constructed using vectors. Specifically they define vector spaces where sets of vectors in the space “add up” to another vector, an analog to Euclidean space where measurements can be added to result in another valid measurement. Hilbert spaces are particularly useful when studying the Fourier expansion of a particular function. In the Fourier transform, a complex function describing a waveform is re-expressed (transformed) into the sum of many simpler wave functions. A Hilbert space describes the “universe of possible solutions” given one particular such function. The Hilbert space inverse wave (HSIW) algorithm of the present invention enables an inverse for any multistatic or multimonostatic geometry with any combination of sources, receivers, and frequencies.
In a radial reflection device of the present invention, such as an intravascular ultrasound probe having an outer diameter between about 0.25 mm and about 5 mm, or a probe configured to non-destructively characterize buried wastes (e.g., tracking plumes of underground contaminants of materials), evaluating the state of materials residing in waste drum barrels or weapons, or to non-destructively evaluate parts with existing access holes (e.g., automobile parts), acquired data are collected at discrete angular locations. Such angular locations are denoted by:
R n t ≡R 0 (cos θ n , sin θ n ) (1)
for transmitter locations, where θ n =nΔθ src for n=0,1 . . . , N src −1, where N src 2π/Δθ, and Δθ src is the source angular increment.
Similarly, receiver locations are given by:
R m r ≡R o (cos θ m , sin θ m ) (2)
where θ m =mΔθ rcv for m=0,1 . . . , N src −1, where N rcv 2π/Δθ rcv , and Δθ rcv is the receiver angular increment.
For each source, configured receiver(s) can record a backscattered field as a time series that can be digitized for processing. Discrete Fourier transforming the time series data result in the spectrum of one or more measured wave forms at discrete frequencies. The forward scattering equation under the Born approximation with both spatial and frequency diversity is given by:
ψ B scat ( R m r ,R n t ,ω l )= P (ω l ) k O 2 (ω l )∫ dr ′ G ( R m r ,r ′ ,ω l ) o ( r ′ ) G ( r ′ ,R n t ,ω l ), (3)
where ω l ,l=0,1. . . , N f −1 are the discrete frequencies and N f is the number of frequencies in the pulse band width.
The HSIW as disclosed herein interprets Equation (3) as a mapping from a continuous object space to a discrete measurement space. The object space is the physical (x,y) space of the object function. The measurement space includes discrete angles and temporal frequencies at which the scattered data are collected. The scattering operator projects the object onto the measurement space. The forward propagation or projection kernel is defined as:
Π*( r )≡ P (ω l ) k O 2 (ω l ) G ( R m r ,r,ω l ) G ( r,R n t ,ω l ), (4)
where Π(r) is a J≡(N src ×N rcv ×N f ) element column vector, and P(ω l ) is the incident pulse spectrum. Mathematically, the projection is represented as an inner product between the object function and the kernel via:
D=∫dr Π*( r ) o ( r )≡<Π, o >, (5)
where D is a J element column vector, and where each element represents a particular source, receiver, and frequency combination. Symbolically, the forward scattering operator, K, is defined as:
K[•]≡∫drΠ*( r )[•]. (6)
The HSIW method of the present invention is employed to derive an inverse of the operator as shown in equation (6). The singular value decomposition (SVD) of K is given as:
K=USV † , (7)
where the columns of U form an orthonormal set of column vectors, u j , which span a measured data space, and the components of V form an orthonormal set of vectors, v j (r), which span an object space. S is a diagonal matrix of singular values, σ j . It is emphasized that the u j are complex column vectors where as the v j (r) are complex functions of r. The set of normal equations for such a singular system are:
Kv j ( r )=σ j u j , (8)
K † u j =σ j v j ( r ), (9)
KK † u j =σ j Kv j ( r )=σ j 2 u j , (10)
K † Kv j ( r )=σ j K † u j ( r )=σ j 2 v j ( r ), (11)
The inversion method of the present invention estimates the object function of equation (5) given measured data in D. Such an inversion incorporates expanding the object function in terms of v j (r):
o ^ ( r ) = ∑ j = 0 J - 1 α j v j ( r ) , ( 12 )
where the α j are constant coefficients to be determined. Substituting the object expansion into equation (5) results in:
D
=
∫
ⅆ
r
Π
*
(
r
)
∑
j
=
0
J
-
1
α
j
v
j
(
r
)
=
∑
j
=
0
J
-
1
α
j
∫
ⅆ
r
Π
*
(
r
)
v
j
(
r
)
,
(
13
)
Applying the definition of the K operator in equation (6) to equation (8) yields an expression for the integral of equation (13),
Kv j =∫dr Π*( r ) v j ( r )=σ j u j , (14)
which reduces equation (13) to:
D
=
∫
∑
j
=
0
J
-
1
α
j
σ
j
u
j
,
(
15
)
Using the orthogonality of the u j vectors, the unknown α j is solved as follows:
u i † D = ∑ j = 0 J - 1 α j σ j u i † u j = ∑ j = 0 J - 1 α j σ j δ ij = α i σ i , ( 16 )
resulting in:
α
i
=
u
i
†
D
σ
i
,
(
17
)
The adjoint of the forward scattering operator, K † and the singular values and singular vectors, σ j , u j , and v j (r) are now required. First, the following inner product equation defines the adjoint,
< u,Kv >=< K † u,v>, (18)
Using the definition of the forward scattering operator from equation (16) results in:
u † ∫dr Π*( r ) v ( r )=∫ dr ( u † Π*( r )) v ( r ), (19)
By comparing the right hand sides of equations (18) and (19), the following definition of the adjoint of the forward scattering operator is obtained:
K † [•]≡[•]·Π T ( r ). (20)
The σ j and u j are determined by solving the eigenvalue equation of equation (10) formed by the outer product of the forward scattering operator with its adjoint. Explicitly, the outer product is represented by:
(∫ dr Π*( r )Π T ( r )) u j =σ j 2 u j , (21)
which is a J×J eigenvalue equation of the form Ax=λx. The Π(r) vectors are known analytically and can be evaluated numerically. It follows that the elements of the outer product matrix can be computed numerically and the resulting system solved numerically for the σ j 2 and u j . Given these and using equation (19) to solve for v j (r) results in:
v
j
(
r
)
=
1
σ
j
Π
T
(
r
)
u
j
.
(
22
)
Substituting equations (17) and (22) into equation (12) yields the final expression for the reconstruction:
o
^
(
r
)
=
∑
j
=
0
J
-
1
1
σ
j
2
Π
T
(
r
)
u
j
u
j
†
D
.
(
23
)
As described above, the Π(r) vectors of equation (4), and outer products and eigenvalues of equation (21) are computed numerically. The measurement system of the analytically described invention only measures part of the scattered field due to the aperture and the loss of the evanescent field information and accordingly, some of the eigenvalues, σ j 2 , are close to zero. Those eigenvalues and their corresponding eigenvectors determine the rank of the outer product matrix, and they must not be used in the reconstruction of equation (23). Thus, in the method of the present invention, a Best Rank N approximation is used to select the number of singular values/vectors. A ratio is computed as follows:
R ( N ) = ∑ j = 0 N - 1 σ j 2 ∑ j = 0 J - 1 σ j 2 , ( 24 )
where the singular values are assumedly arranged from smallest to largest: σ 0 2 ≦σ 1 2 ≦σ J−1 2 . Plotting R(N), the point at which the function starts to rise rapidly is graphically identified. The index of the singular value at which this occurs is labeled as J 0 . With this value determined, a final reconstruction is as follows:
o
^
(
r
)
=
∑
j
=
J
0
J
-
1
1
σ
j
2
Π
T
(
r
)
u
j
u
j
†
D
(
25
)
The HSIW as disclosed herein is flexible in that it allows any transducer configurations of the present invention and any number of frequencies to be used in forming such a final reconstruction.
Changes and modifications in the specifically described embodiments can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the claims. | A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a “pitch/catch” operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for manufacturing a micromechanical structure, and to a micromechanical structure.
2. Description of the Related Art
Although it is applicable to any micromechanical components, the present invention and its underlying problem will be explained with reference to acceleration and rotation rate sensors.
Published German patent application document DE 195 37 814 A1 discloses a method for manufacturing micromechanical sensors, for example acceleration and rotation rate sensors. Movable silicon structures, whose motions are sensed quantitatively by determining capacitance changes, are generated. The movable silicon structures are generated in an etching step, trenches being generated with a high aspect ratio in the silicon layer. In a second step a sacrificial layer, for example an oxide layer, is removed from beneath the micromechanical functional layer made of silicon. In a subsequent process the movable silicon structures thereby obtained are hermetically closed off, for example with a cap wafer that is applied using a seal-glass soldering process.
Published German patent application document DE 199 61 578 A1 discloses the generation, directly on a base wafer by way of further process steps, of a cap over the movable sensor surfaces. For this, a layer of oxide is applied on the base wafer, on which the movable silicon structures have already been etched but the sacrificial layer has not yet been removed. The thickness of this oxide layer is small compared with the thickness of the micromechanical functional layer. The oxide layer must, however, close off the trenches, and for this reason it is possible to provide only narrow trenches. A layer that is transparent to the medium used for sacrificial layer etching, for example a thick polysilicon layer into which very narrow holes are etched, is applied onto the oxide layer. The cover layer having thereby been made transparent, all sacrificial layers located therebeneath are then removed in order to make the silicon structures movable. In a final step, the cover layer is hermetically sealed with a further oxide layer or metal layer or polysilicon layer. Only movable structures having relatively little freedom of movement can be arranged beneath the cover layer.
A situation similar to that relating to the closing off of deep, broader structures also exists in the region of the actual movable structures. If a movable structure is arranged over a buried conductive path, an edge in the movable structure also occurs, because of the manufacturing method, at edges in the buried conductor path. This structure can strike against the edge of the buried conductor path and damage it. To prevent this, bumps can be generated in the movable structure by way of an additional sacrificial layer. The movable structure then, with its bumps, strikes against the conductor areally at defined positions, but freedom of movement is thereby further limited. This concept functions, however, only if the buried conductor path is thinner than the sacrificial layer.
This situation also exists when two movable structures are to be disposed one above another, or when a conductor path plane is to be used over a movable structure. In such cases it is usually necessary to design the movable structures to be thicker than the sacrificial layer.
BRIEF SUMMARY OF THE INVENTION
The idea on which the present invention is based is that of providing, after formation of the first functional layer, firstly for a patterning of the first functional layer, in which only very narrow trenches are trenched into the functional layer. The trenches are embodied to be sufficiently narrow that they can subsequently be filled up by the first insulation layer.
The first insulation layer is then patterned, once again only narrow holes and/or lands being generated as etch accesses. The regions between the filled trenches can then be completely etched via an isotropic etching process. The trenches filled with the insulation material, or the lands made of insulation material, serve in this context on the one hand laterally as an etch stop layer, and on the other hand as stabilization for the thin oxide layer located thereabove, if the latter is to be extended out over large areas. With the further deposition of a second thin insulation layer, the narrow etch accesses in the first insulation layer are then preferably closed off again. The two insulation layers serve, during subsequent execution of the process, as an electrical insulation layer and as a sacrificial layer, respectively.
The manufacturing method according to the present invention for a micromechanical structure, with which method it is possible to etch a first micromechanical functional layer, by way of narrow etch accesses, in such a way that recesses which have a substantially greater width than the etch accesses located thereabove can also be formed therein, allows low edge loss.
Large open areas can be generated in the first micromechanical functional layer, it being necessary only to close off the narrow etch accesses before a further functional layer is deposited. The method does not generate topography effects in the subsequent planes, and the use of thin first micromechanical functional layers. The conformation and extent of the recesses in the first micromechanical functional layer is variable over a wide range.
The recesses can have, for example, a width from typically 0.8 μm to 30 μm. Smaller widths (0.8 to 5 μm) are necessary for acceleration sensors and for the electrode regions of rotation rate sensors. Recesses up to 30 μm wide are necessary for the vibrating structure of rotation rate sensors, and can be manufactured in the same process.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 a to 1 j show schematic cross-sectional views to explain a method for manufacturing a micromechanical structure in accordance with a first embodiment of the present invention.
FIG. 2 shows a schematic planar depiction of a Z sensor having an asymmetrical rocker that is manufactured by the method according to FIGS. 1 a to 1 j.
FIGS. 3 a to 3 c show various embodiments of shapes of etch stop trenches in the first micromechanical functional layer in the context of the method for manufacturing a micromechanical structure in accordance with the first embodiment of the present invention.
FIG. 4 shows a schematic planar depiction to explain a disposition of etch stop trenches in the first micromechanical functional layer, and etch access trenches in the first insulation layer, in the context of a method for manufacturing a micromechanical structure in accordance with the further embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In the Figures, identical reference characters refer to identical or functionally identical elements.
FIGS. 1 a to 1 j are schematic cross-sectional views to explain a method for manufacturing a micromechanical structure in accordance with a first embodiment of the present invention.
Referring to FIG. 1 a , a base insulation layer 2 is deposited over a silicon substrate 1 . This base insulation layer 2 can now optionally be patterned in order to, for example, connect the next functional plane thereabove to substrate 1 . Optionally, one or more functional layers 3 , for example made of polysilicon, can then be deposited and patterned. As process execution continues, a first insulation layer 4 is then deposited on this or these functional layer(s) 3 . This first insulation layer 4 serves, as execution continues, as a sacrificial layer or insulation layer or anchoring layer. First insulation layer 4 can of course also optionally be patterned in order to create electrical and/or mechanical contact with the next functional layer located thereabove.
As process execution continues, first micromechanical functional layer 5 is deposited on first insulation layer 4 . This can be done, for example, using an LPCVD method or in a combined method with an LPCVD starting layer and an epitaxic layer of polysilicon located thereabove. First micromechanical functional layer 5 made of polysilicon can then optionally be planarized using a polishing method (chemical-mechanical polishing, CMP). This may be necessary, depending on the substructure or thickness of first micromechanical functional layer 5 , in order to obtain sufficiently good lithographic resolution in the subsequent step.
Referring further to FIG. 1 b , a resist mask 6 is provided over first micromechanical functional layer 5 , said mask having openings 6 a with which, in a subsequent process step, the polysilicon therebeneath of first micromechanical functional layer 5 will be trenched.
FIG. 1 c shows the state of the process after performance of the trenching step, in which narrow first trenches 7 , extending as far as first insulation layer 4 , are formed in first micromechanical functional layer 5 .
The maximum width of the narrow trenches 7 or holes (not depicted) is selected in such a way that the holes or trenches 7 can be closed off again by a further deposition (to be described later).
As depicted in FIG. 1 d , a second insulation layer 8 is deposited on first micromechanical functional layer 5 after the formation of first trenches 7 . Preferably, micromechanical functional layer 5 can first be thermally oxidized, since such oxide layers are very well sealed later in terms of etching attack, e.g. in plasma using SF 6 . After a pre-oxidation of this kind, a further oxide layer, for example, is applied to the desired target thickness by LPCVD-TEOS deposition. By selecting a CVD oxide for thickening and for completely filling up first trenches 7 it is possible to avoid, specifically in deep trenches, excessive stress in first micromechanical functional layer 5 , since with a CVD oxide it is possible to adjust the stress over a wide range with respect to a thermal oxide by appropriate selection of the system parameters. Both compression-stressed and tension-stressed oxide layers can be deposited here, enabling design leeway in terms of the stress configuration of the oxide layer.
Etch accesses 9 , which locally expose first micromechanical functional layer 5 , are then formed in second insulation layer 8 . The width of these first etch accesses 9 is selected in such a way that they can be completely closed off again by an oxide deposition operation (yet to be described) performed later.
As depicted in FIG. 1 e , recesses 10 are then etched into first micromechanical functional layer 5 in an etching step. Isotropic methods are preferably utilized for this. The gas phase method has proved particularly favorable for this, since it can be difficult to rinse out liquid etching media from the under-etched regions through the narrow first etch accesses 9 . An exemplifying method is an etching process using SF 6 in a plasma, or using ClF 3 or XeF 2 . In the context of this etching of the first micromechanical functional layer, the oxide-filled first trenches 7 and first insulation layer 4 located therebelow serve as an etch stop. In other sub-regions, etching of the polysilicon of first micromechanical functional layer 5 can be limited by way of the etching time. In addition, second insulation layer 8 (made of oxide) deposited into the narrow trenches 7 can serve to stabilize this layer. With large areas of this kind, it is additionally favorable to embody etch accesses 9 in second insulation layer 8 in such a way that stress in that layer can be dissipated by the geometrical disposition of the etch accesses. For example, a meander-like disposition of etch accesses 9 can be used, or long, mutually offset etch accesses 9 (see FIG. 2 ).
Referring further to FIG. 1 f , deposition of a third insulation layer 11 of oxide occurs in order to close off etch accesses 9 in second insulation layer 8 . Second insulation layer 8 and third insulation layer 11 together form a further sacrificial and insulation layer. The manufacturing method described here does not, in particular, result in the creation of any substantial topography at sites at which first micromechanical functional layer 5 has been etched.
In a further embodiment (not depicted), second insulation layer 8 is polished back in order to ensure complete closure of etch accesses 9 upon deposition of third insulation layer 11 .
As depicted in FIG. 1 g , one or more contact regions 12 of first micromechanical functional layer 5 are then exposed by removing second insulation layer 8 and third insulation layer 11 at the relevant locations by way of an etching process. Contact regions 12 of this kind define connections to a further micromechanical functional layer 13 of polysilicon which is to be deposited later and which is then, as depicted in FIG. 1 h , deposited over the resulting structure.
In a manner known per se, second micromechanical functional layer 13 is then patterned in order to form second etch accesses 14 in second micromechanical functional layer 13 , which locally expose third insulation layer 11 , as depicted in FIG. 1 i.
Lastly, referring to FIG. 1 j , a further etching process takes place in order to remove second and third insulation layers 8 , 11 completely, and to remove first insulation layer 4 except for residual regions R at which first micromechanical functional layer 5 is anchored on substrate 1 . This process state corresponds to the state shown in FIG. 1 j . In addition, a cover layer (not depicted) can also be deposited, or a combination of further functional layers and/or cover layers.
FIG. 2 is a schematic planar depiction of a Z sensor having an asymmetrical rocker which is manufactured using the method according to FIGS. 1 a to 1 j.
In FIG. 2 , reference character 100 designates a Z sensor to be formed in first micromechanical functional layer 5 , having a rocker 101 having an asymmetrical mass distribution and a torsion spring 102 anchored on substrate 1 . Etch accesses 7 , which, for example, should be very narrow in a Z sensor of this kind in order to ensure a high level of damping, can easily be manufactured with the method according to the present invention. Typical hole and slot widths from 0.2 to 2 μm can be achieved. These structures are patterned only by the first etching step, and are then closed off with the manufacture of second and third insulation layer 8 , 11 .
Etch stop trenches 7 a , 7 b make possible removal of first micromechanical functional layer 5 over a large area; reference character 9 indicates the etch accesses for polysilicon etching. In order to obtain a stable second insulation layer 8 , large regions can be stabilized with additional support points. It is useful to configure these support points either as a periodically repeating dot pattern or as a pattern of lands.
FIGS. 3 a to 3 c show various embodiments of shapes of etch stop trenches in the first micromechanical functional layer in the context of the method for manufacturing a micromechanical structure in accordance with the first embodiment of the present invention.
All the etch stop trenches 7 that are etched in first micromechanical functional layer 5 before the deposition of second insulation layer 8 should preferably be designed in such a way that T-intersections ( FIG. 3 a ) or angled edges ( FIG. 3 b ) are avoided. Such T-intersections or analogous X-intersections according to FIG. 3 a for etch stop trenches 7 ′ have different widths b 1 , b 2 at the intersection points and along the arms. The same applies to angled edges for etch stop trenches 7 ″ according to FIG. 3 b.
In addition, the trenching process causes at angled edges of this kind a widening of the trenches as a result of the locally larger open area. The two effects can be avoided by using etch stop trenches 7 ′″ in accordance with FIG. 3 c.
It is technically possible for all the trenches 7 ″ that are required as etch stop trenches for the polysilicon etching step to be manufactured continuously, without intersection. Care should be taken in this context that trenches 7 ′″ that are designed to support large open areas in first micromechanical functional layer 5 are not connected to the trenches that function as an etch stop.
FIG. 4 is a schematic planar depiction to explain a disposition of etch stop trenches in the first micromechanical functional layer and etch access trenches in the first insulation layer, in the context of a method for manufacturing a micromechanical structure in accordance with the further embodiment of the present invention.
FIG. 4 depicts an etch access pattern and etch stop trench pattern for a large-area region FB. Etch stop trench 7 ′ a here is an annularly peripheral etch stop trench, and etch stop lands 7 ′ b are disposed alternatingly perpendicularly to one another.
Etch accesses 9 for polysilicon etching are disposed, in non-intersecting and non-overlapping fashion, between etch stop trenches 7 ′ a , 7 ′ b.
Although the present invention has been explained above with reference to two exemplifying embodiments, it is not limited thereto but instead can be varied in many ways.
The micromechanical method according to the present invention for manufacturing a micromechanical structure, and the corresponding micromechanical structure, can be used in particular for acceleration sensors or rotation rate sensors.
Although the present invention has been explained with reference to preferred exemplifying embodiments, it is not limited thereto. In particular, the aforesaid materials and topologies are merely exemplifying, and are not limited to the examples explained.
The utilization sectors are also construed broadly, and are not limited to acceleration and rotation rate sensors. | A method for manufacturing a micromechanical structure includes: forming a first insulation layer above a substrate; forming a first micromechanical functional layer on the first insulation layer; forming multiple first trenches in the first micromechanical functional layer, which trenches extend as far as the first insulation layer; forming a second insulation layer on the first micromechanical functional layer, which second insulation layer fills up the first trenches; forming etch accesses in the second insulation layer, which etch accesses locally expose the first micromechanical functional layer; and etching the first micromechanical functional layer through the etch accesses, the filled first trenches and the first insulation layer acting as an etch stop. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates to a fluidized bed heat exchanger and, more particularly, to a support structure for supporting heat exchange tubes in the heat exchanger and for supporting the various sections of the tubes relative to each other.
The use of fluidized beds has been recognized as an attractive means of generating heat in a heat exchanger such as a boiler, a combustor, a gasifier, or the like. In these arrangements, air is passed through a bed of particulate material which normally consists of a mixture of inert material and a fossil fuel such as coal to fluidize the bed and to promote the combustion of the fuel. When the heat produced by the fluidized bed is utilized to convert water to steam such as in a steam generator, for example, the fluidized bed system offers an attractive combination of high heat release, improved heat transfer to surfaces within the bed and compact size.
In these type arrangements, a plurality of heat exchange tubes are usually connected to an external inlet header and extend in a serpentine relationship within the housing of the heat exchanger. The tubes are normally supported in an elevated position slightly above the grid plate of the heat exchanger by a refractory pier support, or the like. However, the latter does not permit an adequate flow of air, which normally flows through the grid, to those portions of the tubes which rest on the supports. Therefore, the latter tube portions become excessively hot and can lead to premature failure and hot spots within the bed. Also, if the tube sections extend across the bed for a relatively large distance, they tend to sag at their end portions and therefore do not attain a perfectly horizontal position within the housing which is important for optimum efficiency of the heat exchange process.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a fluidized bed heat exchanger in which the heat exchange tubes are supported above the grid plate in a manner to permit cooling air to flow over those portions of the tubes supported relative to the grid plate.
It is a further object of the present invention to provide a heat exchanger of the above type in which the various sections of the heat exchange tubes are supported in a manner to prevent sagging of the sections.
Toward the fulfillment of these and other objects, the apparatus of the present invention includes a grid plate supported in a housing for receiving a bed of particulate material at least a portion of which is combustible. At least one perforated support pier projects out from the surface of the grid plate and air is passed through the grid plate, the support pier and the material to fluidize the material. A plurality of heat exchange tubes extend within the housing and are supported by the support pier so that the air passing through the pier also passes over the tubes. A ladder type support structure is provided between adjacent tube sections to support the sections relative to each other.
BRIEF DESCRIPTION OF THE DRAWINGS
The above brief description, as well as further objects, features, and advantages, of the present invention will be more fully appreciated by reference to the following detailed description of a presently preferred but nonetheless illustrative embodiment in accordance with the present invention, when taken in connection with the accompanying drawings wherein:
FIG. 1 is a vertical sectional view of a portion of a fluidized bed unit incorporating features of the present invention;
FIG. 2 is an enlarged perspective view of a portion of the structure shown in FIG. 1;
FIG. 3 is an enlarged partial, vertical sectional view of a portion of the structure shown in FIG. 1;
FIG. 4 is a cross-sectional view taken along the line 4--4 of FIG. 3;
FIG. 5 is a partial view similar to FIG. 3 but depicting an alternate embodiment of the present invention;
FIG. 6 is a cross-sectional view taken along the line 6--6 of FIG. 5;
FIG. 7 is a view similar to FIG. 6 but showing another alternative embodiment of the present invention;
FIG. 8 is a view similar to FIG. 5 but depicting still another alternative embodiment of the present invention;
FIG. 9 is a sectional view taken along the line 9--9 of FIG. 8; and
FIG. 10 is an enlarged partial sectional view of a support structure for the heat exchange tubes in accordance with a further alternative embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring specifically to FIG. 1 of the drawings, the present invention will be described in connection with a fluidized bed boiler, shown in general by the reference numeral 10 and consisting of a front wall 12, a rear wall 14, and two sidewalls, one of which is shown by the reference numeral 16. Each wall consists of a layer of insulation material 18 extending between an inner plate 20 and an outer sheathing 22. The upper portion of the boiler is not shown for the convenience of presentation it being understood that it consists of a convection section, a roof and an outlet for allowing the combustion gases to discharge from the boiler in a conventional manner.
A bed of particulate material, shown in general by the reference numeral 24, is disposed within the boiler 10 and rests on a perforated grid plate 26 disposed in the lower portion of the boiler. The bed 24 can consist of a mixture of discrete particles of inert material and fuel material such as bituminous coal which are introduced into the bed through feeders 28 extending through one of the sidewalls 16.
An air plenum chamber 30 is provided immediately below the grid plate 26 and communicates with an air inlet 32 provided through the rear wall 14 for distributing air from an external source (not shown) to the chamber 30. A pair of dampers 34 are disposed in the inlet 32 and are adapted for pivotal movement about their centers in a conventional manner in response to actuation of external controls (not shown) to vary the effective opening in the inlet and thus control the flow of air through the inlet and into the compartment 30. A bed light-off burner 36 is mounted through the front wall 12 immediately above the grid plate 26 for initially lighting off the bed 24 during startup, in a conventional manner.
Referring to FIGS. 1 and 2, a pair of support beams 40 and 42 (FIG. 2) are mounted adjacent the sidewalls 16 for supporting the grid plate 26. As shown in FIG. 1, the grid plate 26 is bent near its edges adjacent the walls 12 and 14 and in an intermediate location intermediate said edges to form two support piers 46 and 48 extending along the latter edges and a support pier 50 extending midway between the two support piers 46 and 48. As better shown in FIG. 2, the support pier 50 is formed by bending the grid plate 26 upwardly, horizontally and then downwardly to form a hollow pier having a rectangular cross section which includes the perforations normally present on the flat portion of the grid plate 26.
As shown in FIG. 1, the support piers 46 and 48 are formed by bending the portions near the edges of the grid plate upwardly and then horizontally with the edge portions of the piers resting against the walls 12 and 14, respectively. As in the case of the pier 50 each pier 46 and 48 is hollow and includes the grid plate perforations.
Referring again to FIG. 2, a beam 52, having a cross-sectional shape in the form of an inverted "T", extends between, and is welded at its ends to, a pair of vertical support beams 54 and 56 which are connected to and extend upwardly from the support beams 40 and 42, respectively. The beam 52 extends within the support pier 50 with the upper flange of the beam extending through a slot formed through the upper surface of the pier and projecting outwardly from the latter surface.
As better shown in FIG. 1, a plurality of heat exchange tubes 60 extend across the boiler 10 immediately above the grid plate 26 and within the bed 24. The tubes 60 are connected between an inlet header 61 and an outlet header 62 for respectively supplying heat exchange fluid, such as water, to the tubes and for receiving the water after it is passed through the tubes.
As shown in FIG. 1, additional support beams 52 are provided in connection with the piers 46 and 48 and, although not shown in the drawings, it is understood that they extend between two vertical support beams which are constructed and disposed in a manner similar to the beams 54 and 56. The support beams 52 are located relative to the support piers 46 and 48 in the same manner as in the case of the support pier 50, with the upper flanges of the beams extending through slots formed through the upper surfaces of the piers and projecting outwardly from the latter surfaces.
Each heat exchange tube 60 extends in a serpentine relationship to form a plurality of spaced parallel sections with each section of each tube extending horizontally and parallel to the other sections of the other tubes and in horizontal alignment with the sections of the other tubes. The lower section of each tube 60 extends across the projecting upper flanges of the support beams 52 associated with the piers 46, 48 and 50 and the upper section of each tube is located slightly below the upper level of the bed 24.
A support structure is provided above each pier 46, 48 and 50 for supporting the various sections of each heat exchange tube 60 relative to each other and is better shown in connection with pier 50 in FIGS. 3 and 4. In particular, the support structure consists of a plurality of plates 63 extending between the vertically adjacent sections of the tube sections, with each plate being welded at its ends to the lower surface and upper surface, respectively, of each tube section. A plurality of horizontally extending rods 64 are welded between adjacent plates to add structural stability to the support structure. This same support structure is also utilized in connection with the end portions of the sections of the heat exchange tubes 60 above the piers 46 and 48 as shown in FIG. 1. It is noted that in the latter cases, the support structure, i.e., the support plates 63 and the rods 64, extend between every other section of the tubes 60 since a support structure is not necessary between the tube sections adjacent the respective bends in the tube.
An alternate embodiment of the support structure for supporting adjacent sections of the tubes 60 is shown in FIGS. 5 and 6. In particular, instead of the plates 63 and support rods 64 utilized in the aforementioned embodiment, each tube section is provided with an annular ring 66 which extends around the tube section and which engages the corresponding annular ring disposed on the vertically adjacent tube section. In this manner, the sections of the tubes 60 are supported relative to each other immediately above the piers 46, 48 and 50, with each tube section being provided with the annular ring 66 in the area above the support pier 50 and with every other tube section being provided with an annular ring in the area above the support piers 46 and 48 for the reasons indicated above.
The embodiment of FIG. 7 is identical to that of FIG. 6 with the exception that in the former embodiment, the tube sections of a particular tube 60 are vertically offset from those of its adjacent tubes with the annular rings 66 abutting as in the previous embodiment to provide the support.
In the embodiment of FIGS. 8 and 9, the sections of the adjacent tubes 60 are disposed in horizontal alignment and two fins 70 extend from the lower portion of each tube section (with the exception of the lowermost sections) and a single fin 72 extends from the upper portion of each section (with the exception of the uppermost sections). The fin 72 extends between the two fins 70 of the vertically adjacent tube sections with the length or height of the fins 72 being dimensioned to correspond to the optimum vertical distance between adjacent tube sections. The fins 70 are slightly smaller in length than the fins 72 and operate to limit the relative horizontal movement of the fins 72 and therefore the horizontal movement between the adjacent tube sections.
The embodiment of FIG. 10 is designed to provide a support structure for the end portions of the tube sections in a configuration in which the inner plates forming the inner portion of the walls 12, 14 and 16 of the previous embodiments are replaced by a plurality of spaced tubes 74. Each tube 74 has a fin 76 disposed integral with, or welded to, the tube at diametrically opposed sections of the tube and extending for the entire length thereof. Although not clear from the drawings it is understood that the fins extending between adjacent tubes are connected together to form a gas-tight structure forming the inner portion of each of the walls 12, 14 and 16.
According to this embodiment, the piers 46 and 48 and the support structure associated therewith are replaced by a plurality of fingers 78 which are welded to the fins extending between adjacent tubes. A plurality of support lugs 80 are provided with each being supported by a corresponding finger 78 and each having a knurled portion 82 that engages the bent portions of the heat exchange tubes 60 as shown. A finger 78 and support lug 80 would be utilized in connection with each bent section of each heat exchange tube 60 and would be connected in the appropriate place along the lengths of several of the fins 76 extending between adjacent tubes.
It is thus seen that, according to each of the foregoing embodiments of the present invention, the heat exchange tubes are supported above the grid plate in a manner to permit cooling air to flow over those portions of the tubes supported relative to the grid plate and the various sections of the heat exchange tubes are supported relative to each other to prevent sagging of the sections.
A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein. | A fluidized bed heat exchanger in which a grid plate is supported in a housing for receiving a bed of particulate material, at least a portion of which is combustible. At least one perforated support pier projects from the surface of the grid plate and air is passed through the grid plate, the support pier and the material to fluidize the material. One or more heat exchange tubes extend within the housing and are supported by the support pier so that the air passing through the pier also passes over the tubes. Each tube extends in a serpentine relation to form a plurality of spaced parallel sections and a support structure is provided for supporting the sections relative to each other. | 5 |
FIELD OF THE DISCLOSURE
[0001] Described herein is an improved, commercially viable and industrially advantageous process for the preparation of paliperidone intermediate, 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one and its hydrochloride salt.
BACKGROUND
[0002] U.S. Pat. Nos. 4,804,663 and 5,158,952 disclose a variety of 3-piperidinyl-1,2-benzisoxazole derivatives, processes for their preparation, pharmaceutical compositions comprising the derivatives, and methods of use thereof. These compounds have long-acting antipsychotic properties and are useful in the treatment of warm-blooded animals suffering from psychotic diseases. Among them, paliperidone, (═)-3-[2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl]-6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one, is an antipsychotic agent and indicated for the both acute (short-term) and maintenance (long-term) treatment of schizophrenia. Paliperidone is represented by the following structural formula:
[0000]
[0003] Processes for the preparation of paliperidone and related compounds are disclosed in U.S. Pat. No. 5,158,952, U.S. Pat. No. 5,254,556 and U.S. Pat. No. 5,688,799.
[0004] In the preparation of paliperidone, 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one of formula I:
[0000]
[0000] is a key intermediate. According to U.S. Pat. Nos. 5,158,952 (hereinafter referred to as the '952 patent) and 5,254,556 (hereinafter referred to as the '556 patent), the compound of formula I can be prepared by the reaction of an optionally protected 2-aminopyridine compound with an α-acyl lactone compound in the presence of an activating reagent and in a suitable reaction-inert solvent such as toluene at a temperature 90° C. followed by treatment with ammonium hydroxide. The activating reagents include halogenating reagents such as, for example, phosphoryl chloride, phosphoryl bromide, phosphorous trichloride, thionyl chloride, and preferably phosphoryl chloride. The reaction mass is extracted with the solvents such as trichloromethane and then subjected to column chromatographic purifications.
[0005] The compound of formula I obtained by the process described in the '952 and the '556 patents is generally not of satisfactory purity. Unacceptable amounts of impurities are generally formed during the reaction between the 2-aminopyridine compound and the α-acyl lactone compound when the reaction is carried out in the presence of solvents like toluene, thus resulting in a poor product yield. In addition, the reaction proceeds at higher temperatures, and the process involves the additional step of column chromatographic purifications. Methods involving column chromatographic purifications are generally undesirable for large-scale operations, thereby making the process commercially unfeasible.
[0006] According to the U.S. Pat. No. 5,688,799 (hereinafter referred to as the '799 patent), the compound of formula I is prepared by the reaction of 2-amino-3-hydroxypyridine with 2-acetylbutyrolactone in the presence of p-toluenesulfonic acid in xylene solvent at reflux temperature for overnight using a water separator to yield 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one. The 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one is converted into its hydrochloride salt, followed by reaction with thionyl chloride in dimethylformamide to produce 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one.
[0007] The synthetic route for the compound of formula I as described in the '799 patent involves a lengthy process, the yields obtained in this process are very low, and also the process produces a product of unsatisfactory purity. This process is also commercially unfeasible. Moreover, the intermediate compound 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one obtained in this process is poorly soluble in xylene, resulting in deposit formation on the wall of the reaction vessel and discoloration of the reaction mixture to black. Furthermore, the reaction with thionyl chloride is characterized by a very severe smell, likely caused by reaction of residual 2-acetylbutyrolactone remaining from the previous step. The process generally results in a product of unreproducible yield and quality.
[0008] PCT Publication No. WO 2006/027370 describes a modified process for preparation of 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one involving the reaction of 2-amino-3-hydroxypyridine with 2-acetylbutyrolactone in the presence of p-toluenesulfonic acid and using chlorobenzene as a solvent at reflux temperature, i.e., at 125° C. The product is isolated by a process involving the addition of alcoholic solvent and filtration of the reaction mixture at 90-95° C.
[0009] The process described in WO 2006/027370 involves a lengthy process, the reaction proceeds at a high temperature i.e., above 125° C., it takes 19 hours for reaction completion, and also involves the hazard of filtration of a reaction mixture containing flammable solvents at 90-95° C. which poses problems in scale up operations. Based on the aforementioned drawbacks, this process may be unsuitable for preparation of the compound of formula I at laboratory scale and commercial scale operations.
[0010] A need remains for an improved and commercially viable process of preparing the compound of formula I or an acid addition salt thereof that will solve the problems associated with the processes described in the prior art, and that will be suitable for large-scale preparation. Desirable process properties include reduced reaction times, and greater simplicity, purity and yield of the product, thereby enabling the production of paliperidone and its pharmaceutically acceptable acid addition salts in high purity and in high yield.
SUMMARY
[0011] The present inventors have surprisingly found that paliperidone intermediate, 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one, can be prepared in high purity and with high yield with a reduced reaction time by using phosphorous oxychloride as both a solvent and reactant in the reaction between 2-amino-3-hydroxypyridine and 2-acetylbutyrolactone instead of using reaction inert solvents like toluene. In one aspect, the process for the production of 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one requires no reaction-inert solvent.
[0012] In an aspect, provided herein is an efficient, convenient and commercially viable process for the preparation of paliperidone intermediate, 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one, and its hydrochloride salt. Advantageously, in the process described herein, no chromatographic separations are required for the isolation of pure 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one, thereby making the process commercially viable.
DETAILED DESCRIPTION
[0013] In accordance with the present invention, there is provided an improved process for preparation of paliperidone intermediate, 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one of formula I:
[0000]
[0000] or its hydrochloride salt thereof which comprises:
a) reacting 2-amino-3-hydroxypyridine of formula II:
[0000]
[0015] with 2-acetylbutyrolactone of formula III:
[0000]
[0016] in the presence of phosphorous oxychloride to produce a reaction mass;
b) quenching the reaction mass in a mixture of ice and water to form a quenched reaction mass; c) adjusting the pH of the quenched reaction mass to 4-6 with a base to produce a separated substantially pure compound of formula 1; d) collecting the separated substantially pure compound of formula I; and e) optionally converting the compound of formula I into its substantially pure hydrochloride salt by reacting the separated substantially pure compound of formula 1 with an alcoholic or gaseous hydrogen chloride in a solvent selected from an alcoholic solvent and an aromatic solvent.
[0021] The reaction in step-(a) is carried out at a temperature of 20° C. to 70° C., specifically 25° C. to 70° C., and more specifically 25 to 60° C.
[0022] As used herein, “reaction-inert solvent” refers to a solvent which is inert to the reaction partners under the reaction conditions described herein, especially a solvent that is immiscible or only very poorly miscible with water, for example toluene, xylene, and the like.
[0023] In one embodiment, 1 to 2 equivalents of 2-acetylbutyrolactone of formula III per equivalent of 2-amino-3-hydroxypyridine of formula II are employed, specifically 1 to 1.3 equivalents of 2-acetylbutyrolactone per equivalent of the 2-amino-3-hydroxypyridine.
[0024] In one embodiment, 2.4 to 7 equivalents of phosphorous oxychloride per equivalent of 2-amino-3-hydroxypyridine of formula II are employed, specifically 3 to 6 equivalents of phosphorous oxychloride, and more specifically 3 to 4 equivalents of phosphorous oxychloride per equivalent of 2-amino-3-hydroxypyridine.
[0025] In another embodiment, the pH of the reaction mass in step-(c) is adjusted to 5-6.
[0026] The base used to adjust the pH in step-(c) is an organic or inorganic base. In one embodiment, the base is an aqueous solution of an inorganic base. Exemplary inorganic bases are aqueous ammonia; and hydroxides, carbonates, bicarbonates, alkoxides and oxides of alkali or alkaline earth metals. Exemplary alkali metal compounds are those of lithium, sodium and potassium, specifically those of sodium and potassium. Exemplary alkaline earth metal compounds are those of calcium and magnesium, specifically those of magnesium. Specific exemplary inorganic bases include aqueous ammonia, sodium hydroxide, potassium hydroxide, magnesium hydroxide, magnesium oxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium tert-butoxide potassium tert-butoxide, and combinations comprising one or more of the foregoing inorganic bases. Specifically, the inorganic base is aqueous ammonia, sodium hydroxide, or potassium hydroxide, and more specifically aqueous ammonia.
[0027] The separated substantially pure compound of formula I in step-(d) is collected by filtration or centrifugation. The compound of formula I obtained is then optionally subjected to drying using conventional drying techniques like vacuum oven drying.
[0028] The compound of formula I obtained in step-(d) has a purity (measured by High Performance Liquid Chromatography, hereinafter referred to as ‘HPLC’) greater than about 97%, specifically greater than about 99%, and more specifically greater than about 99.5%.
[0029] The term “substantially pure compound of formula I or its hydrochloride salt” refers to the compound of formula I or its hydrochloride salt having purity greater than about 97%, specifically greater than about 99% and more specifically greater than about 99.5% (measured by HPLC).
[0030] Exemplary alcoholic solvents for use in step-(e) include methanol, ethanol, n-propanol, 2-propanol, n-butanol, tert-butanol, and combinations comprising one or more of the foregoing solvents. A specific alcoholic solvent is methanol.
[0031] Exemplary aromatic solvents for use in step-(e) are toluene, xylene, and the like, and combinations comprising one or more of the foregoing solvents. A specific aromatic solvent is toluene.
[0032] In one embodiment, the alcoholic hydrogen chloride used in step-(e) is methanolic hydrogen chloride.
[0033] In one embodiment, the purity (measured by HPLC) of the product obtained is greater than about 97%, specifically greater than about 99%, and more specifically greater than about 99.5%.
[0034] Paliperidone and pharmaceutically acceptable acid addition salts of paliperidone can be prepared in high purity by using the substantially pure compound of formula I or its hydrochloride salt obtained by the methods disclosed herein, by known methods, for example as described in U.S. Pat. No. 5,158,952.
HPLC Method Used in the Specification is Provided Below:
[0035]
[0000]
Column:
Xterra - C18 or equivalent (150 mm × 4.6 mm, 5.0μ)
Mobile phase:
20 mM phosphate buffer & methanol
Elution:
Gradient
Flow rate:
1.0 ml/min
UV wave length:
237 nm
Injection volume:
20.0 μL
Total run time:
35.0 min
Test solution:
10.0 mg of 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-
pyrido [1,2-a]pyrimidin-4-one in 10 ml volumetric
flask and make up to the mark with diluent
(Methanol:water (1:1)).
[0036] The following examples are given for the purpose of illustrating the present invention and should not be considered as limitation on the scope or spirit of the invention.
EXAMPLES
Example 1
Preparation of 9-Hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one
[0037] To a mixture comprising phosphorus oxychloride (2520 parts) and 2-amino-3-hydroxy pyridine (300 parts) was charged 2-acetyl butyrolactone (348 parts). The resulting mixture was heated to 60° to 65° C. and stirred for 10 hours at the same temperature. The reaction mass was cooled and poured into a mixture of ice and salt to produce a quenched reaction mass. The pH was adjusted (pH meter) to 5.5 using aqueous ammonia. The resulting solid was filtered and washed with water followed by drying in vacuum oven to yield 235 parts of 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one with a purity (HPLC) of 99%.
[0038] 1 H-NMR (CDCl 3 ): δ 2.576 (3H, s), δ 3.189 (2H, t) δ 3.841 (2H, t), δ 4.3 (1H, bs), δ 7.022 (1H, m) δ 7.1 (1H, t) δ 8.46 (1H, d).
Example 2
Preparation of 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one Hydrochloride
[0039] 9-Hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one (235 parts) was added into methanol (1300 parts) which was then acidified and the pH was adjusted with 10-13% methanolic HCl (500 part) from 0-1. The reaction mass was concentrated into a thick slurry, filtered and washed with chilled methanol (100 parts). The product was dried at 60° C. under vacuum (700 mm Hg) to yield 219 parts of 9-Hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one with HPLC purity above 98%.
[0040] 1 H-NMR (D 2 O): δ2.414 (3H, s), δ 2.723 (2H, t) δ 3.904 (2H, t), δ 7.602 (1H, m), δ 7.747 (1H, d), δ 8.732 (1H, d).
[0041] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. The term wt % refers to percent by weight. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0042] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. | Described herein is an improved, commercially viable and industrially advantageous process for the preparation of paliperidone intermediate 9-hydroxy-3-(2-chloroethyl)-2-methyl-4h-pyrido[1,2-a]pyrimidin-4-one and its hydrochloride salt. The process provides the paliperidone intermediate in higher yield and reduced reaction time compared to the previously disclosed processes, thereby providing for production of paliperidone and its pharmaceutically acceptable acid addition salts in high purity and in high yield. | 2 |
BACKGROUND
This disclosure relates to a joint between a vane and shroud, for use in a gas turbine engine.
Gas turbine engine vane assemblies typically include vanes having airfoils mounted between two rings or partial rings (shrouds) that form a flowpath for the gas turbine engine. The vanes are typically brazed to the shrouds, and may have lugs at radial ends received in slots in the shrouds.
One application for such an assembly is in a compressor. Generally, there are vane assemblies intermediate rotor stages in the compressor.
In the prior art, the lugs are inserted into slots in radially inner and outer shrouds. Some flowable attachment material, such as a brazing material, has typically been deposited between the lugs and the slots. There have been two basic types of this structure used. In a first type, the lugs extend radially inward of the outer shroud and radially outwardly of the inner shroud. These enlarged lugs provide a dam preventing the flowable attachment material from extending to locations on the airfoil. However, these enlarged lugs also present an obstruction to a desired air flow cross-sectional area between the airfoils.
It is also known to have the lugs not extend radially beyond the shroud walls. With this structure, the flowable attachment material could move beyond the lug and toward surfaces of the airfoil which can cause damage to the vanes.
These and other features of this application will be best understood from the following specification and drawings, the following of which is a brief description.
SUMMARY
In a featured embodiment, a vane and shroud for a gas turbine engine include a center axis with a shroud having a radial wall facing substantially radially with respect to the center axis. A slot wall defines a slot in the shroud. A relief wall defines a relief area of the slot and extends between the radial wall and the slot wall. A vane has an airfoil and a lug extending into the slot. A flowable attachment material is disposed in the relief area for engagement of the vane to the shroud.
In another embodiment according to the previous embodiment, the slot is larger than the lug, such that said flowable attachment material is also disposed between the lug and the slot wall.
In another embodiment according to any of the previous embodiments, the relief area has a triangular cross-section.
In another embodiment according to any of the previous embodiments, the relief area has a curved cross-section.
In another embodiment according to any of the previous embodiments, the relief area has a rectangular cross-section.
In another embodiment according to any of the previous embodiments, the lug merges into a transition section which curves circumferentially inwardly from the lug to the airfoil.
In another embodiment according to any of the previous embodiments, the radial wall is generally radially aligned with a radial extent of the transition section which is most adjacent to the radial wall.
In another embodiment according to any of the previous embodiments, a depth of the relief wall is defined to a point most radially distant from a surface of the radial wall facing the center axis. A radial wall thickness is defined for the shroud adjacent to the relief area, and a ratio of the depth to the radial wall thickness is between about 0.2 and 0.6.
In another featured embodiment, a vane assembly includes a circumferentially extending outer shroud and a circumferentially extending inner shroud centered on a center axis. A plurality of vanes is positioned radially between the inner and outer shrouds. A joint is between the vanes and at least one of the inner and outer shrouds. The at least one shroud has a radial wall facing substantially radially with respect to the center axis. A plurality of slots is in the at least one shroud. Slot walls define the slots in the at least one shroud. A relief wall defines a relief area of the slots and extends between the radial wall and the slot wall. The vanes have an airfoil and a lug extending into one of the slots. A flowable attachment material is disposed in the relief area for engagement of the vane to at least one of the inner and outer shrouds.
In another embodiment according to the previous embodiment, the slot is larger than the lug, such that said flowable attachment material is also disposed between the lug and the wall.
In another embodiment according to any of the previous embodiments, the relief area has a triangular cross-section.
In another embodiment according to any of the previous embodiments, the relief area has a curved cross-section.
In another embodiment according to any of the previous embodiments, the relief area has a rectangular cross-section.
In another embodiment according to any of the previous embodiments, the lug merges into a transition section which curves circumferentially from the lug to the airfoil.
In another embodiment according to any of the previous embodiments, the radial wall is generally radially aligned with a radial extent of the transition section which is most adjacent to the radial wall.
In another embodiment according to any of the previous embodiments, the at least one shroud is the outer shroud.
In another embodiment according to any of the previous embodiments, a depth of the relief area is defined to a point most radially distant from a surface of the radial wall facing the center axis. A radial wall thickness is defined for the shroud adjacent to the relief area, and a ratio of the depth to the radial wall thickness is between about 0.2 and 0.6.
In another featured embodiment, a gas turbine engine has a compressor section, a combustor section and a turbine section. The compressor section and the turbine section are defined by a plurality of rotor stages and a plurality of vane assemblies positioned between adjacent ones of the rotor stages. At least one of the vane assemblies has a circumferentially extending outer shroud and a circumferentially extending inner shroud centered on a center axis. A plurality of vanes is positioned radially between the inner and outer shrouds. A joint is between the vanes and at least one of the inner and outer shrouds such that the at least one shroud has a radial wall facing substantially radially with respect to the center axis. A plurality of slots is in the at least one shroud. Slot walls define the slots in the at least one shroud. A relief wall defines a relief area of the slots and extends between the radial wall and the slot wall. The vanes have an airfoil and a lug extending into one of the slots. A flowable attachment material is disposed in the relief area for engagement of the vane to at least one of the inner and outer shrouds
In another embodiment according to the previous embodiment, the at least one of vane assemblies is in the compressor section.
In another embodiment according to any of the previous embodiments, the at least one shroud is the radially outer shroud.
These and other features may be best understood from the following drawings and specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic, cross-sectional side view of an embodiment of a gas turbine engine.
FIG. 2 shows a vane assembly for use in FIG. 1 .
FIG. 3 is an enlarged view of the area inside the box 3 of FIG. 2 .
FIG. 4A illustrates a first embodiment of a vane and shroud.
FIG. 4B shows a detail of FIG. 4A .
FIG. 5A is a view of a second embodiment vane and shroud.
FIG. 5B shows a detail of FIG. 5A .
FIG. 6A is a view of a third embodiment vane and shroud.
FIG. 6B is a detail of FIG. 6A .
DETAILED DESCRIPTION
FIG. 1 schematically illustrates a gas turbine engine 20 . The gas turbine engine 20 is shown herein is a two-spool turbofan that generally incorporates a fan section 22 , a compressor section 24 , a combustor section 26 and a turbine section 28 . Alternative engines might include an augmentor section (not shown) among other systems or features. The fan section 22 drives air in a bypass flowpath B and also drives air along a core flowpath C for compression and communication into the compressor section 24 , and combustor section 26 , then expansion through the turbine section 28 . Although depicted as a turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures, and ground-based power generating engines.
The engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38 . It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided.
The low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42 , a low pressure (or first) compressor section 44 and a low pressure (or first) turbine section 46 . The inner shaft 40 is connected to the fan 42 through a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool 30 . The high speed spool 32 includes an outer shaft 50 that interconnects a high pressure (or second) compressor section 52 and high pressure (or second) turbine section 54 . A combustor 56 is arranged between the high pressure compressor 52 and the high pressure turbine 54 . A mid-turbine frame 57 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine 46 . The mid-turbine frame 57 supports one or more bearing systems 38 in the turbine section 28 . The inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis A, which is collinear with their longitudinal axes. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine.
The core airflow C is compressed by the low pressure compressor 44 then the high pressure compressor 52 , mixed and burned with fuel in the combustor 56 , then expanded over the high pressure turbine 54 and low pressure turbine 46 . The mid-turbine frame 57 includes airfoils 59 which are in the core airflow path. The turbines 46 , 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion.
As known, the compressor sections 44 and 52 include rotating blade stages 18 and intermediate vane assemblies 19 . Both of these structures are shown schematically. It is known that the blades 18 typically rotate with a rotor. The vanes 19 typically are provided in the form of a ring, with vanes extending radially between an inner shroud and an outer shroud. The turbine sections 44 and 46 also have blades 18 and vane assemblies 19 .
The engine 20 in one example is a high-bypass geared aircraft engine. In a further example, the engine 20 bypass ratio is greater than about six (6), with an example embodiment being greater than ten (10), the geared architecture 48 is an epicyclic gear train, such as a star gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine 46 has a pressure ratio that is greater than about 5. In one disclosed embodiment, the engine 20 bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor 44 , and the low pressure turbine 46 has a pressure ratio that is greater than about 5:1. Low pressure turbine 46 pressure ratio is pressure measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans. In addition, gas turbine engines for other applications such as land-based power generation turbines may also benefit from the teachings of this application.
A vane assembly 150 for use in a compressor section of a gas turbine engine is illustrated in FIG. 2 . As seen in FIG. 2 , inner shroud 60 and outer shroud 70 may be segmented for easier installation within the engine 20 . Only a circumferential portion of the vane assembly 150 is shown. As known, a plurality of segments 65 are connected together, and typically form a full ring. Inner shroud 60 has a plurality of slots, and an outer shroud 70 has a plurality of slots 75 . A plurality of vanes 17 are disposed in the slots in the inner shroud 60 and the outer shroud 70 .
Referring to FIG. 3 , an outer portion of the vane 17 is disposed in a slot 75 in outer shroud 70 . Typically, lugs 90 (e.g., see lug 90 in FIG. 4A ) are used to attach the vanes 17 to the outer shroud 70 . Some flowable attachment material, which is appropriate for securing the respective metals of the vane 17 and the shrouds 60 and 70 may be utilized. Various brazing materials are known, and would be appropriate for the teachings of this application.
Referring to FIG. 4A , lugs 90 are shaped to generally fit into respective slots 75 . Vane 17 has a curved transition section 100 formed to merge an airfoil 80 into lug 90 by curving circumferentially inwardly. A maximum stress area 105 exists where the transition section 100 blends in the airfoil 80 .
As is clear, the slot 75 is larger than lug 90 , so there is clearance. A brazing material 120 is disposed in the clearance, and used to secure the lugs 90 to the shroud 70 . Material 120 does not substantially contact area 105 during the brazing because of chamfers or relief areas 101 formed by a relief wall 135 formed in radially inner wall 140 . This will be explained below. This lack of contact prevents fatigue at area 105 and thereby extends the life of the vane assembly 150 . At the same time, the lightweight and aerodynamic configuration does not cause flow obstruction that could otherwise reduce engine efficiency.
In this embodiment, an outer extent 102 of the transition section 100 may be in register (i.e., aligned) with inner wall 140 of the outer shroud 70 to not obstruct air flow. Alternatively, the outer extent 102 of the transition section 100 may be radially outwardly of the inner wall 140 , as this would also eliminate obstruction to air flow. The slot 75 is generally defined by the slot walls 145 . As can be seen, the relief walls 135 are formed as chamfers. The relief wall 135 extends in a direction with a radially outer component, and a component in a circumferential direction, such that the resulting shape is triangular, or a chamfer. The relief area 101 provides an area for the brazing material 120 to flow when it is heated, thereby minimizing a possibility that the brazing material 120 might reach the transition section 100 or the maximum stress area 105 .
FIG. 4B shows shroud 70 has a wall thickness t 1 . A radially outermost point 200 of the relief wall 135 extends to a distance d 1 away from the inner wall 140 . In embodiments, t 1 may be between 0.08-0.1″ (0.20-0.25 cm). Notably, t 1 may be the same across the embodiments of FIGS. 4B and 5B . In such embodiments, d 1 may be between 0.02-0.05″ (0.05-1.3 cm). A ratio of d 1 to t 1 , or a ratio of the deepest portion of the relief area to the wall thickness of the shroud may be between about 0.2 and 0.6.
FIG. 5A shows another embodiment wherein the relief area 201 is formed by a curved relief wall 235 , which in this embodiment may be a circular section. The relief area 201 will function much like the relief area in the FIG. 4A embodiment to provide a space for the flowable material to move, such that it does not move onto the transition section 100 .
FIG. 5B shows the wall thickness t 1 of the shroud 70 , and that the depth of the relief area 235 is formed at a radius r 1 . In embodiments, r 1 may be between 0.02-0.05″ (0.05-1.3 cm). Thus, a ratio of r 1 to t 1 may be between about 0.2 and 0.6.
FIG. 6A shows another relief area embodiment 301 wherein the shape of the relief wall 335 is generally rectangular. Again, this shape will provide space to receive the flowable attachment material.
FIG. 6B shows a detail of the relief wall 335 . The distance d 2 to the deepest portion of the relief wall, measured away from the wall 140 , was between 0.02-0.05″ (0.05-1.3 cm). Again, a ratio of d 2 to t 1 may be between about 0.2 and 0.6.
The distance t 1 could be defined as the radial wall thickness of the shroud measured adjacent to the relief area. The dimensions d 1 , d 2 , and r 1 could all be defined as a depth of the relief area measured to a point most radially distant from an inner surface of the wall 140 .
The relief areas work generically to limit flowable attachment material from flowing into the transition section 100 since the flowable attachment material maintains a relatively high viscosity, even when fluent. The material will tend to move into an area of lesser resistance created by the relief areas, rather than turning the corner, such as at outer extent 102 , and moving onto the transition section 100 .
In accordance with the methods of this application, the outer lug 90 is inserted into the outer slot, and an inner lug is inserted into an inner slot. The vane may be tack welded to the shrouds. The flowable attachment material is then deposited between the slots and the lugs, and the assembly is heated to allow the flowable attachment material to move to a final position at which it hardens, and to create the vane assembly 150 .
While the disclosure of this application has been directed to the outer shroud, a worker of ordinary skill in the art would recognize that all of these teachings would apply equally to an inner shroud, and may be utilized at both the inner and outer shrouds.
Although an example embodiment has been disclosed, a person of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For instance, a relief area may be created within the transition section. For this reason, the following claims should be studied to determine their true scope and content. | A stator joint for a gas turbine engine has a center axis, and a shroud having a radial wall facing substantially radially with respect to the center axis. A slot wall defines in-part a slot in the shroud. A relief wall defines a relief area of the slot. The relief wall extends between the radial wall and the slot wall. A vane has an airfoil and a lug extending into the slot. A flowable attachment material is disposed in the relief area for engagement of the vane to the shroud. A vane assembly and a gas turbine engine are also disclosed. | 8 |
TECHNICAL FIELD OF THE INVENTION
[0001] The invention relates to a new type of acenaphtho heterocyclic compounds identified as small molecule Bcl-2 inhibitors. These compounds can simulate BH3-only protein, competitively bind and antagonizie Bcl-2, Bcl-xL and Mcl-1 proteins in vitro and in vivo, to induce cell apoptosis. Therefore, they can be used as anticancer compounds.
BACKGROUND OF THE INVENTION
[0002] The molecule targeted antitumor drug is becoming a hot spot in new drug research and development and a new generation product during marketization after cytotoxic agents as antitumor drugs. Bcl-2 protein is the most important molecular target for antagonizing and reversing the immortality of malignant tumors. Therefore, specific antagonizing Bcl-2 protein will achieve the goals of anticancer therapy with high selectivity, safety, high performance and low painfulness by inducing intently apoptosis in tumor cells. Among Bcl-2 inhibitors, BH3 analogues (BH3 mimetics) with high selectivity exhibit the most remarkable antitumor effect, the best pharmacodynamic activity and the lowest toxic side effects. In addition, such inhibitors also must possess broad spectrum antagonizing ability on the anti-apoptotic members (including Bcl-2, Bcl-xL and Mcl-1 proteins) of the Bcl-2 family in order to gain single-agent efficacy and limited resistance.
[0003] However, until now, there are still no marketed antitumor products using Bcl-2 as target. Among the existing 19 pre-clinical Bcl-2 inhibitors, 3 optimal products are in phase I, phase II and phase III clinical trials respectively, they are ABT-737 researched and developed by Abbott Laboratories, Illinois, USA; Obatoclax (GX15-070) researched and developed by Gemin X; and AT-101 researched and developed by Ascenta in USA. They all are BH3 analogues. The competitive binding constant is up to grade nM with Bcl-2 protein, which is far higher than other 15 similar molecules. However, they all have the following deficiencies: the BH3 analogous level of Gossypol and Obatoclax is insufficient, they are not the authentic BH3 analogue, in other words, they possess cytotoxicity independent on BAX/BAK. This indicates that other target points exist, thus they have toxic side effects. Although ABT-737 is the authentic BH3 analogue, it cannot bind with Mcl-1 and cannot inhibit the Bcl-2 family proteins with broad spectrum, thereby severely limiting its application scope.
[0004] The present inventors disclosed a series of acenaphtho heterocyclic compounds of 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile, and disclosed that these compounds had the activity of inhibiting tumor growth through inducing cell apoptosis (Chinese patent, Authorized Announcement No. CN1304370C). However, as a potential antitumor drug on basis of apoptosis, its research and development faces the same difficulties as the similar drugs: the complexity of apoptosis signal gateway, the potential and intensive cytotoxicity as well as the inevitable blindness resulted from taking medicine. All of these are the important reasons for the failure in the development of such similar drugs. Therefore, the targeting effect of drugs should be prominently emphasized in the research course.
SUMMARY OF THE INVENTION
[0005] The present invention aims to provide compounds, which have stronger targeting and can be used as BH3 analogue, Bcl-2 family protein (including Bcl-2, Bcl-xL and Mcl-1 proteins) inhibitors.
[0006] One goal of the present invention is to provide acenaphtho heterocyclic compounds. They have the following structural formula:
[0000]
[0007] wherein:
[0008] R 1 is selected from H, thiomorpholinyl or XR 4 ;
R 2 is selected from (CH 2 ) n Z or (CH 2 ) n Ph-(o,m,p)Z; Z is selected from NO 2 , Ph, CF 3 , OCH 3 , SCH 3 , NH 2 , NHCH 3 , N(CH 3 ) 2 , unsubstituted linear or branched C 1-8 alkyl and linear or branched C 1-8 alkyl that is substituted with halogen, amino, hydroxyl, ester or carboxyl;
[0010] R 3 is selected from (CH 2 ) n W, W is selected from H, CN, NO 2 , NH z , COOH, CHO, OH or SO 3 H;
[0011] R 4 is selected from (CH 2 ) n Y, thenoyl, tetrahydropyrane, tetrahydrothiapyran and (CH 2 ) n Ph-(o,m,p)Y; Y is selected from a straight or branched C 1-8 alkyl, wherein the straight or branched C 1-8 alkyl can be unsubstituted linear or substituted by halogen, amino, hydroxyl, ester or carboxyl;
[0012] X is selected from O, S, amino, carbonyl, ester, amide or sulfamide.
[0013] n is 0 to 4.
[0014] In the preferential technical proposal, Z is selected from a straight or branched C 1-4 alkyl, wherein the straight or branched C 1-4 alkyl can be unsubstituted or substituted.
[0015] In further preferential technical proposal, R 2 is selected from (CH 2 ) n Ph-(o,m,p)Z, wherein Z is selected from a straight or branched C 1-3 alkyl that can be unsubstituted or substituted.
[0016] In further preferential technical proposal, W is selected from H, NH 2 or OH.
[0017] In further preferential technical proposal, X is selected from O or S.
[0018] In further preferential technical proposal, R 4 is selected from Ph-(CH 2 ) n Y, wherein Y is selected from Ph, CF 3 , OCH 3 , SCH 3 , NH 2 , Br, isopropyl, isobutyl or secbutyl.
[0019] In certain embodiments, the compound of formula I is selected from:
[0020] 9-(butylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0021] 9-(hexylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0022] 9-(3-phenylpropylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0023] 3-ethoxy-9-(3-phenylpropylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0024] 3-benzoyl-9-(butylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0025] 9-(butyl(methyl)amino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0026] 3-(4-bromophenylthio)-9-(butylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0027] 3-(4-bromophenylthio)-9-(3-phenylpropylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0028] 9-(butylamino)-3-thiomorpholino-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0029] 9-(3-phenylpropylamino)-3-thiomorpholino-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0030] 9-(butylamino)-3-(4-isopropylphenoxy)-8H-acenaphtho[1,2-b]pyrrol-8-one;
[0031] 3-(4-isopropylphenoxy)-9-(3-phenylpropylamino)-8H-acenaphtho[1,2-b]pyrrol-8-one.
[0032] In another aspect of the invention, the general procedures used to synthesize the compounds of Formula I are described that the compounds of Formula i react with NH 2 CHR 2 R 3 under the room temperature for 0.5-8 h.
[0000]
[0033] In the condensation, the optimum mole ration of compounds of Formula i to NH 2 CHR 2 R 3 is 1:5 and the solvent is acetonitrile.
[0034] wherein, the definition of the substituent is the consistent with the Formula I.
[0035] The general procedure used to synthesize the compounds of Formula I is a mild synthetic route. 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and its derivatives react with NH 2 CHR 2 R 3 under the room temperature for 0.5-8 h. A series of amino-substituted acenaphtho heterocyclic compounds were obtained. As followed:
[0000]
[0036] Based on the previous acenaphtho heterocyclic compounds, we obtain a series of new compounds of Formula I after the analysis and experiments. These compounds share common features, amino-substituted at 9-position. The statistical results demonstrated that these acenaphtho heterocyclic compounds enhance the inhibition capability against Bcl-2 and Mcl-1 proteins to some extent, can also be used to prepare the BH3 analogue, Bcl-2 family protein inhibitors, and further be used to prepare the antitumor drugs having high targeting.
[0037] In another aspect of the invention, the acenaphtho heterocyclic compounds of the present invention have the following structural Formula II:
[0000]
[0000] wherein:
[0038] R 5 , R 6 and R 7 are each independently selected from XR 9 or H;
[0039] R 8 is selected from CN, COOH, COOR 10 or CONHR 10 ;
[0040] X is selected from O, carbonyl, ester, amide or sulfamide;
[0041] where R 9 is selected from (CH 2 ) n Y or (CH 2 ) n Ph-(o, m, p)Y; Y is selected from unsubstituted linear or branched C 2-8 alkyl and linear or branched C 1-8 alkyl that is substituted with halogen, amino, hydroxyl, ester or carboxyl;
[0042] where R 10 is selected from unsubstituted linear or branched C 1-6 alkyl that is substituted with halogen, amino, hydroxyl, ester, carboxyl or (CH 2 ) n Ph-(o, m, p)Z; Z is selected from CH 3 , C 2 H 5 , NO 2 , Ph, F, Cl, Br, CF 3 , OCH 3 , SCH 3 , NH 2 , N(CH 3 ) 2 ;
[0043] X is S;
[0044] where R 9 is selected from (CH 2 ) n Ph-(o, m, p)Y; Y is selected from linear or branched C 2-8 alkyl and linear or branched C 1-8 alkyl that is substituted with halogen, amino, hydroxyl, ester or carboxyl;
[0045] where R 10 is selected from unsubstituted linear or branched C 1-6 alkyl and linear or branched C 1-6 alkyl that is substituted with halogen, amino, hydroxyl, ester, carboxyl or (CH 2 ) n Ph-(o, m, p)Z; Z is selected from CH 3 , C 2 H 5 , NO 2 , Ph, F, Cl, Br, CF 3 , OCH 3 , SCH 3 , NH 2 , N(CH 3 ) 2 ;
[0046] n is 0 to 4.
[0047] In the preferential technical proposal, R 5 and R 6 are each independently selected from XR 9 or H.
[0048] In further preferential technical proposal, R 8 is CN.
[0049] In further preferential technical proposal, R 9 is selected from (CH 2 ) n Ph-(o, m, p)Y. In further preferential technical proposal, X is selected from 0 or S; Y is selected from linear or branched C 3-5 alkyl.
[0050] In further preferential technical proposal, Y is selected from isopropyl, isobutyl or secbutyl.
[0051] In further preferential technical proposal, the compound of formula II is selected from:
[0052] 3-(4-sec-butylphenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0053] 4-(4-sec-butylphenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0054] 3-(4-isobutylphenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0055] 4-(4-isobutylphenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0056] 3-(4-isopropylphenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0057] 3-(4-isobutylphenylthio)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0058] 4-(4-isobutylphenylthio)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0059] 3-(4-isopropylphenylthio)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile;
[0060] 3-(4-sec-butylphenylthio)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile.
[0061] In another aspect of the invention, the compounds of the present invention can be synthesized by the following a or b routes:
[0062] a. In the first route, the raw material 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile having excellent rigid, coplanarity and strong electron deficiency undergoes aromatic hydrogenous nucleophilic substitution reaction with the nucleophilic reagents such as alcohol, thioalcohol, phenol or thiophenol, to obtain 3-, 6- or 3,6-substituted 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile. After the carbonitrile being hydrolyzed, esterified and amidated, the corresponding acid, ester and amide are obtained. The reaction formula is as follows:
[0000]
[0063] b. In the second route, the raw material acenaphthenequinone and the solvent concentrated sulfuric acid are added into liquid bromine and refluxed for 2 hours to obtain 5-bromoacenaphthylene-1,2-dione. The resulting bromoacenaphthene reacts with alcohol, thioalcohol, phenol, thiophenol, ester or amide to obtain the corresponding substituted acenaphthenequinone iv, as follows:
[0000]
[0064] The resulting substituted acenaphthenequinone reacts with acetonitrile under the weak acid condition, such as gel silica, to obtain 3-(2-oxo-2H-acenaphthene)-malononitrile. After that, the reaction products are catalyzed by K 2 CO 3 and refluxed with acetonitrile for 0.5-6 hours. Then cool and vaporize some solvent under decompression conditions. The corresponding 3- or 4-monosubstituted oxy-8-oxo-8 H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (ii or iii) is obtained by filtering or direct column chromatography. After the carbonitrile being hydrolyzed, esterified and amidated, the corresponding acid, ester and amide are obtained.
[0000]
[0065] Wherein, the definition of the substituent is the consistent with the Formula II. The substituent group R in different replace sites is distinguished into R5 or R6.
[0066] Based on previously discovered acenaphtho heterocyclic compounds, the present invention screened for a series of new compounds with structural formula II by means of various analysis and experiments. The results demonstrated that the acenaphtho heterocyclic compounds in present invention have similar or more excellent BH3 analogous level than that have been published. They can also be used to prepare the BH3 analogue, Bcl-2 family protein inhibitors.
[0067] Therefore, one objective of the present invention is to provide the uses of the above-mentioned acenaphtho heterocyclic compounds in manufacturing the BH3 analogue, Bcl-2 family protein inhibitors. It also includes formulation procedures of compounds with structural formula I and II, and the composition comprises an effective dose of the acenaphtho heterocyclic compounds and a moderate amount of pharmaceutical adjuvant. According to the test results in the examples, the effective dose of compounds needed to fulfill the uses in the present invention might be lower than those have been previously published. Furthermore, another objective of the present invention is to provide the uses of the above-mentioned acenaphtho heterocyclic compounds in manufacturing antitumor drugs having high targeting.
BRIEF DESCRIPTION OF DRAWINGS
[0068] There are 13 drawings in the present invention, wherein:
[0069] FIG. 1 is the dynamic curve of the compound 1 and FAM-Bid peptide competitively binding Bcl-2 protein detected by the ELISA method;
[0070] FIG. 2 is the dynamic curve of the compound 1 and FAM-Bid peptide competitively binding Mcl-1 protein detected by the ELISA method;
[0071] FIG. 3 is the dynamic curve of the compound 13 and FAM-Bid peptide competitively binding Bcl-2 protein detected by the fluorescence polarization method;
[0072] FIG. 4 is the dynamic curve of the compound 13 and FAM-Bid peptide competitively binding Mcl-1 protein detected by the fluorescence polarization method;
[0073] FIG. 5 shows the interactions between Bcl-2 and Bax on a cellular level interfered by the compound 1 (different concentration);
[0074] FIG. 6 shows the interactions between Bcl-2 and Bax on a cellular level interfered by the compound 1 (different action time);
[0075] FIG. 7 shows the positive results of BH3 analogous degree of the compound 1 detected by Bax protein and mitochondria co-localization;
[0076] FIG. 8 shows the negative results of BH3 analogous degree of the compound 1 detected by Bax protein and mitochondria co-localization;
[0077] FIG. 9 shows the results of the cell toxicity of the compound 1 depending on BAX/BAK (Gossypol is nonspecific comparison);
[0078] FIG. 10 is the western blotting electropherogram showing the inhibition of the compound 1 against Mcl-1;
[0079] FIG. 11 is the western blotting electropherogram showing the inhibition of the compound 1 against Bcl-2;
[0080] FIG. 12 is the semiquantitative curve showing the inhibition of the compound 1 against Mcl-1 protein;
[0081] FIG. 13 is the semiquantitative curve showing the inhibition of the compound 1 against Bcl-2 protein;
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0082] Various embodiments of the present invention will now be described more fully with reference to the accompanying drawings.
[0000] Part I: Preparation and Characterization of Compounds against Bcl-2 Family Proteins
EXAMPLE 1
Synthesis and Characterization of 9-n-Butylamino-8H-acenaphtho[1,2-1)]pyrrol-8-one (1)
[0083]
[0084] 0.23 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.49 mL n-butylamine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 1 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 22%.
[0085] Characterization of 9-n-Butylamino-8H-acenaphtho[1,2-b]pyrrol-8-one (1): M.p.232-233° C. 1 H NMR (400M, CDCl 3 ): δ 8.63 (d, J=8.0 Hz, 1H), 8.16 (d, J=8.0 Hz, 1H), 8.13 (d, J=8.4 Hz, 1H), 7.95 (d, J=8.0 Hz, 1H), 7.75 (t, J=8.0 Hz, 1H), 7.67 (t, J=8.0 Hz, 1H), 4.08 (m, 2H), 2.71 (br, 1H), 1.85 (m, 2H), 1.55 (m, 2H), 0.98 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 18 H 16 N 2 O, (m/z): calcd for 276.1263, found 276.1266.
EXAMPLE 2
Synthesis and Characterization of 9-n-Hexylamino-acenaphtho[1,2-b]pyrrol-8-one (2)
[0086]
[0087] 0.23 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.51 mL n-Hexylamine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 1 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 25%.
[0088] Characterization of 9-n-Hexylamino-acenaphtho[1,2-b]pyrrol-8-one (2): M.p.234-235° C. 1 H NMR (400 M, CDCl 3 ): δ 8.65 (d, J=8.0 Hz, 1H), 8.10 (d, J=8.0 Hz, 1H), 8.05 (d, J=8.4 Hz, 1H), 7.98 (d, J=8.0 Hz, 1H), 7.63 (t, J=8.0 Hz, 1H), 7.47 (t, J=8.0 Hz, 1H), 4.09 (m, 2H), 3.69 (br, 1H), 1.84 (m, 2H), 1.55-1.25 (m, 6H), 0.95 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 20 H 20 N 2 O, (m/z): calcd for 304.1576, found 304.1579.
EXAMPLE 3
Synthesis and Characterization of 9-(3-Phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (3)
[0089]
[0090] 0.23 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.77 mL 3-phenylpropan-1-amine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 20%.
[0091] Characterization of 9-(3-Phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (3): M.p.252-253° C. 1 H NMR (400 M, CDCl 3 ): δ 8.61 (d, J=8.0 Hz, 1H), 8.09 (d, J=8.0 Hz, 2H), 7.73 (t, J=8.0 Hz, 2H), 7.54 (t, J=8.0 Hz, 1H), 7.47 (d, J=8.0 Hz, 1H), 7.34 (m, 3H), 7.16 (d, J=8.0 Hz, 1H), 5.9 (br, 1H), 4.09 (m, 2H), 1.84 (m, 2H), 1.25 (m, 2H). TOF MS (EI + ): C 23 H 18 N 2 O, (m/z): calcd for 338.1419, found 338.1415.
EXAMPLE 4
Synthesis and Characterization of 3-Ethoxy-9-(3-phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (4)
[0092]
[0093] 0.27 g 3-Ethoxy-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.77 mL 3-phenylpropan-1-amine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 20%.
[0094] Characterization of 3-Ethoxy-9-(3-phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (4): M.p. 250-251° C. 1 H NMR (400M, CDCl 3 ): δ 8.55 (d, J=8.0 Hz, 1H), 8.42 (d, J=8.0 Hz, 1H), 7.82 (t, J=8.4 Hz, 1H), 7.79 (d, J=8.0 Hz, 1H), 7.41 (t, J=8.4 Hz, 2H), 7.30 (d, J=8.4 Hz, 2H), 7.12 (t, J=8.4 Hz, 1H), 6.60 (d, J=8.4 Hz, 1H), 4.62 (q, J=7.6 Hz, 2H), 2.87 (t, J=8.4 Hz, 2H), 2.62 (t, J=8.4 Hz, 2H), 2.09 (m, J=8.4 Hz, 2H), 2.01 (br, 1H), 1.31 (t, J=7.6 Hz, 3H). TOF MS EI + : C 24 H 20 N 2 O 2 , (m/z): calcd for 382.1681, found 382.1683.
EXAMPLE 5
Synthesis and Characterization of 3-Benzoyl-9-butylamino-acenaphtho[1,2-b]pyrrol-8-one (5)
[0095] 0.33 g 3-Benzoyl-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.47 mL n-butylamine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 20%.
[0000]
[0096] Characterization of 3-Benzoyl-9-butylamino-acenaphtho[1,2-b]pyrrol-8-one (5): M.p. 262-263° C. 1 H NMR (400M, CDCl 3 ): δ 8.96 (d, J=8.0 Hz, 1H), 8.56 (d, J=8.0 Hz, 1H), 8.15 (d, J=8.4 Hz, 1H), 8.01 (t, J=8.0 Hz, 1H), 7.81 (d, J=8.4 Hz, 1H), 7.80 (d, J=8.4 Hz, 2H), 7.68 (t, J=8.4 Hz, 1H), 7.48 (t, J=8.4 Hz, 2H), 3.87 (t, J=8.4 Hz, 2H), 2.01 (br, 1H), 1.62 (m, 1.30 (m, 2H), 0.91 (t, J=7.6 Hz, 3H). TOF MS EI + : C 24 H 20 N 2 O 2 , (m/z): calcd for 380.1525, found 380.1523.
EXAMPLE 6
Synthesis and Characterization of 9-(Butyl-methyl-amino)-acenaphtho[1,2-b]pyrrol-8-one (6)
[0097]
[0098] 0.23 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.51 mL N-methylbutan-1-amine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 1 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 25%.
[0099] Characterization of 9-(Butyl-methyl-amino)-acenaphtho[1,2-b]pyrrol-8-one (6): M.p. 245-246° C. 1 H NMR (400M, CDCl 3 ): δ 8.45 (d, J=8.0 Hz, 1H), 8.30 (d, J=8.0 Hz, 1H), 8.05 (d, J=8.4 Hz, 1H), 7.98 (t, J=8.0 Hz, 1H), 7.87 (d, J=8.0 Hz, 1H), 7.63 (t, J=8.0 Hz, 1H), 3.09 (s, 3H), 2.55 (t, J=8.0 Hz, 2H), 1.39 (m, 2H), 1.29 (m, 2H), 0.95 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 19 H 18 N 2 O, (m/z): calcd for 290.1419, found 290.1415.
EXAMPLE 7
Synthesis and Characterization of 3-(4-Bromo-phenylsulfanyl)-9-butylamino-acenaphtho[1,2-b]pyrrol-8-one (7)
[0100]
[0101] 0.42 g 3-(4-Bromo-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.47 mL n-butylamine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 23%.
[0102] Characterization of 3-(4-Bromo-phenylsulfanyl)-9-butylamino-acenaphtho[1,2-b]pyrrol-8-one (7): M.p.245-246° C. 1 H NMR (400M, CDCl 3 ): δ 8.74 (br, 1H),8.57 (d, J=8.0 Hz, 1H), 8.47 (d, J=8.0 Hz, 1H), 8.44 (d, J=8.0 Hz, 1H), 7.88 (t, J=8.0 Hz, 1H), 7.63 (d, J=8.0 Hz, 2H), 7.56 (d, J=8.0 Hz, 1H), 7.38 (d, J=8.0 Hz, 2H), 3.89 (m, 2H), 1.75 (m, 2H), 1.41 (m, 2H), 0.94 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 24 H 19 BrN 2 OS, (m/z): calcd for 462.0401, found 462.0405.
EXAMPLE 8
Synthesis and Characterization of 3-(4-Bromo-phenylsulfanyl)-9-(3-phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (8)
[0103]
[0104] 0.42 g 3-(4-Bromo-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.77 mL 3-phenylpropan-1-amine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 19%.
[0105] Characterization of 3-(4-Bromo-phenylsulfanyl)-9-(3-phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (8): M.p.272-273° C. 1 H NMR (400 M, CDCl 3 ): δ 8.57 (d, J=8.0 Hz, 1H), 8.47 (d, J=8.0 Hz, 1H), 8.44 (d, J=8.0 Hz, 1H), 7.88 (t, J=8.0 Hz, 1H), 7.63 (m, 4H), 7.56 (d, J=8.0 Hz, 1H), 7.47 (m, 3H), 7.38 (d, J=8.0 Hz, 2H), δ 6.74 (br, 1H), 3.89 (m, 2H), 1.75 (m, 2H), 1.41 (m, 2H). TOF MS (EI + ): C 29 H 21 BrN 2 OS, (m/z): calcd for 524.0588, found 524.0585.
EXAMPLE 9
Synthesis and Characterization of 9-Butylamino-3-thiomorpholin-4-yl-acenaphtho[1,2-b]pyrrol-8-one (9)
[0106]
[0107] 0.33 g 8-Oxo-3-thiomorpholin-4-yl-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.47 mL n-butylamine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2.5 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 25%.
[0108] Characterization of 9-Butylamino-3-thiomorpholin-4-yl-acenaphtho[1,2-b]pyrrol-8-one (9): M.p. 239-240° C. 1 H NMR (400 M, CDCl 3 ): δ 8.59 (d, J=8.0 Hz, 1H), 8.32 (d, J=8.0 Hz, 1H), 8.00 (d, J=8.4 Hz, 1H), 7.68 (t, J=8.0 Hz, 1H), 7.16 (d, J=8.4 Hz, 1H), 6.35 (br, 1H), 4.01 (m, —NHCH 2 CH 2 —, 2H), 3.51 (br s, —N(CH 2 CH 2 ) 2 S), 2.97 (br s, —N(CH 2 CH 2 ) 2 S), 1.84 (m, —NH CH 2 CH 2 CH 2 —, 2H), 1.50 (m, —CH 2 CH 2 CH 2 CH 2 , 2H), 0.95 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 22 H 23 N 3 OS, (m/z): calcd for 377.1562, found 377.1565.
EXAMPLE 10
Synthesis and Characterization of 9-(3-Phenyl-propylamino)-3-thiomorpholin-4-yl-acenaphtho[1,2-b]pyrrol-8-one (10)
[0109]
[0110] 0.33 g 8-Oxo-3-thiomorpholin-4-yl-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.47 mL 3-phenylpropan-1-amine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 2.5 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 18%.
[0111] Characterization of 9-(3-Phenyl-propylamino)-3-thiomorpholin-4-yl-acenaphtho[1,2-b]pyrrol-8-one (10): M.p. 265-266° C. 1 H NMR (400 M, CDCl 3 ): δ 8.58 (d, J=8.0 Hz, 1H), 8.34 (d, J=8.0 Hz, 1H), 8.08 (d, J=8.4 Hz, 1H), 7.68 (m, 4H), 7.16 (m, 3H), 5.05 (br, 1H), 4.00 (m, 2H), 3.52 (br s, —N(CH 2 CH 2 ) 2 S), 2.89 (br s, —N(CH 2 CH 2 ) 2 S), 1.85 (m, 2H), 1.56 (m, 2H). TOF MS (EI + ): C 27 H 25 N 3 OS, (m/z): calcd for 439.1718, found 439.1715.
EXAMPLE 11
Synthesis and Characterization of 9-Butylamino-3-(4-isopropyl-phenoxy)-acenaphtho[1,2-b]pyrrol-8-one (11)
[0112]
[0113] 0.36 g 3-(4-Isopropyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.47 mL n-butylamine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 3 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 23%.
[0114] Characterization of 9-Butylamino-3-(4-isopropyl-phenoxy)-acenaphtho[1,2-b]pyrrol-8-one (11): M.p. 243-244° C. 1 H NMR (400 M, CDCl 3 ): δ 8.69 (d, J=8.0 Hz, 1H), 8.47 (d, J=8.0 Hz, 1H), 8.08 (d, J=8.0 Hz, 1H), 7.69 (t, J=8.0 Hz, 1H), 7.32 (d, J=8.0 Hz, 2H), 7.09 (d, J=8.0 Hz, 1H), 6.90 (d, J=8.0 Hz, 2H), 6.13 (br, 1H), 4.08 (m, 2H), 2.97 (m, 1H), 1.85 (m, 2H), 1.55 (m, 2H), 1.02 (s, 6H), 0.88 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 27 H 26 N 2 O 2 , (m/z): calcd for 410.1994, found 410.1998.
EXAMPLE 12
Synthesis and Characterization of 3-(4-Isopropyl-phenoxy)-9-(3-phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (12)
[0115]
[0116] 0.36 g 3-(4-Isopropyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.77 mL 3-phenylpropan-1-amine were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 3 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 19%.
[0117] Characterization of 3-(4-Isopropyl-phenoxy)-9-(3-phenyl-propylamino)-acenaphtho[1,2-b]pyrrol-8-one (12): M.p. 275-276° C. 1 H NMR (400 M, CDCl 3 ): δ 8.59 (d, J=8.0 Hz, 1H), 8.46 (d, J=8.0 Hz, 1H), 7.98 (t, J=8.0 Hz, 1H), 7.65 (d, J=8.0 Hz, 1H),7.46 (d, J=8.0 Hz, 2H), 7.39 (t, J=8.0 Hz, 2H), 7.31-7.26 (m, 5H), 6.80 (d, J=8.0 Hz, 1H), 5.13 (br, 1H), 3.88 (m, 2H), 2.95 (m, 1H), 1.75 (m, 2H), 1.41 (m, 2H). 1.85 (m, 2H), 1.55 (m, 2H), 1.02 (s, 6H), TOF MS (EI + ): C 32 H 28 N 2 O 2 , (m/z): calcd for 472.2151, found 472.2156.
EXAMPLE 13
Synthesis and Characterization of 3-(4-sec-Butyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (13) and 4-(4-sec-Butyl-benzyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (14)
[0118]
[0119] 0.99 g 5-(4-sec-Butyl-phenoxy)-acenaphthylene-1,2-dione and 0.33 g malononitrile were dissolved in dichloromethane, and then mixture was applied to a gel silica column and eluted quickly. After all the mixture passed through, the column was spun dry. Red solid was obtained with a weight of 1.07 g and a yield of 94%. 0.05 g of K 2 CO 3 and 20 mL of acetonitrile were added into 0.77 g of the red solid. The mixture was heated and refluxed for 3 hours. After the reaction finished, the reaction solution was spun dry and separated by chromatographic column (CH 2 Cl 2 : petroleum ether=1:1) to obtain two isomers.
[0120] Characterization of 13: M.p. 219-220° C. 1 H NMR (400M, CDCl 3 ): δ 8.92 (d, J=8.0 Hz, 1H), 8.65(d, J=8.8 Hz, 1H), 8.46 (d, J=8.0 Hz, 1H), 7.87 (t, J=8.0 Hz, 1H), 7.33 (d, J=8.4 Hz, 2H), 7.14(d, J=8.4 Hz, 2H), 7.04 (d, J=8.0 Hz, 1H), 2.70 (m, 1H), 1.65 (m, 2H), 1.30 (d, J=8.0 Hz, 3H), 0.88 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 25 H 18 N 2 O 2 , (m/z): calcd for 378.1368, found 378.1376.
[0121] Characterization of 14: M.p. 278-279° C. 1 H NMR (400M, CDCl 3 ): δ 8.76 (d, J=7.6 Hz, 1H), 8.60 (d, J=8.0 Hz, 1H), 8.42 (d, J=7.6 Hz, 1H), 7.88 (t, J=8.0 Hz, 1H), 7.40 (d, J=8.0 Hz, 2H), 7.09 (d, J=8.0 Hz, 2H), 6.95 (d, J=8.0 Hz, 1H), 2.70 (m, 1H), 1.65 (m, 2H), 1.30 (d, J=8.0 Hz, 3H), 0.88 (t, J=8.0 Hz, 3H). TOF MS EI + : C 25 H 18 N 2 O 2 , (m/z): calcd for 378.1368, found 378.1362.
EXAMPLE 14
Synthesis and Characterization of 3-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (15) and 4-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (16)
[0122]
[0123] 0.99 g 5-(4-Isopropyl-phenoxy)-acenaphthylene-1,2-dione and 0.33 g malononitrile were dissolved in dichloromethane, and then mixture was applied to a gel silica column and eluted quickly. After all the mixture passed through, the column was spun dry. Red solid was obtained with a weight of 1.07 g and a yield of 94%. 0.05 g of K 2 CO 3 and 20 mL of acetonitrile were added into 0.77 g of the red solid. The mixture was heated and refluxed for 3 hours. After the reaction finished, the reaction solution was spun dry and separated by chromatographic column (CH 2 Cl 2 : petroleum ether=1:1) to obtain two isomers.
[0124] Characterization of 15: M.p. 214-215° C. 1 H NMR (400 M, CDCl 3 ): δ 8.78 (d, J=7.6 Hz, 1H), 8.60(d, J=8.0 Hz, 1H), 8.43 (d, J=7.6 Hz, 1H), 7.67 (t, J=8.0 Hz, 1H), 7.29 (d, J=8.0 Hz, 2H), 7.12(d, J=8.0 Hz, 2H), 6.95 (d, J=8.0 Hz, 1H), 2.42 (d, J=8.0 Hz, 2H), 1.75 (m, 1H), 0.75 (d, J=8.0 Hz, 6H). TOF MS (EI + ): C 25 H 18 N 2 O 2 , (m/z): calcd for 378.1368, found 378.1365.
[0125] Characterization of 16: M.p. 273-274° C. 1 H NMR (400 M, CDCl 3 ): 8 8.72 (d, J=7.6 Hz, 1H), 8.53 (d, J=8.0 Hz, 1H), 8.38 (d, J=7.6 Hz, 1H), 7.98 (t, J=8.0 Hz, 1H), 7.31 (d, J=8.0 Hz, 2H), 7.02 (d, J=8.0 Hz, 2H), 6.80 (d, J=8.0 Hz, 1H), 2.43 (d, J=8.0 Hz, 2H), 1.75 (m, 1H), 0.75 (d, J=8.0 Hz, 6H). TOF MS EI + : C 25 H 18 N 2 O 2 , (m/z): calcd for 378.1368, found 378.1363.
EXAMPLE 15
Synthesis and Characterization of 3-(4-Isopropyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (17)
[0126]
[0127] 1 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 0.54 g 4-Isopropyl-phenol were dissolved in acetonitrile (50 ml), and then heated and refluxed for 3 hours. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 30%.
[0128] Characterization of 3-(4-Isopropyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (17): M.p. 272-274° C.: 1 H NMR (400 M, CDCl 3 ): δ 8.92 (d, J=8.0 Hz, 1H), 8.25 (d, J=8.8 Hz, 2H), 8.44 (d, J=8.0 Hz, 1H), 7.86 (t, J=8.0 Hz, 1H), 7.38 (d, J=8.4 Hz, 2H), 7.14 (d, J=8.4 Hz, 2H), 7.04 (d, J=8.8 Hz, 1H), 3.01 (m, 1H), 1.32 (d, J=8.0 Hz, 6H); TOF MS EI + (m/z): C 24 H 16 N 2 O 2 , calcd for 364.1212, found 364.1215.
EXAMPLE 16
Synthesis and Characterization of 3-(4-Isobutyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (18) and 4-(4-Isobutyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (19)
[0129]
[0130] 1.04 g 5-(4-Isobutyl-phenylsulfanyl)-acenaphthylene-1,2-dione and 0.33 g malononitrile were dissolved in dichloromethane, and then mixture was applied to a gel silica column and eluted quickly. After all the mixture passed through, the column was spun dry. Red solid was obtained with a weight of 0.99 g and a yield of 84%. 0.05 g of K 2 CO 3 and 20 mL of acetonitrile were added into 0.79 g of the red solid. The mixture was heated and refluxed for 3 hours. After the reaction finished, the reaction solution was spun dry and separated by chromatographic column (CH 2 Cl 2 : petroleum ether=1:1) to obtain two isomers.
[0131] Characterization of 18: M.p. 234-235° C. 1 H NMR (400M, CDCl 3 ): δ 8.58 (d, J=7.6 Hz, 1H), 8.41 (d, J=8.0 Hz, 1H), 8.30 (d, J=7.6 Hz, 1H), 7.53 (t, J=8.0 Hz, 1H), 7.31 (d, J=8.0 Hz, 2H), 7.02 (d, J=8.0 Hz, 2H), 6.95 (d, J=8.0 Hz, 1H), 2.75 (m, 1H), 1.69 (m, 2H), 1.29 (d, J=8.0 Hz, 3H), 0.92 (t, J=8.0 Hz, 3H). TOF MS (EI + ): C 25 H 18 N 2 OS, (m/z): calcd for 394.1140, found 394.1142.
[0132] Characterization of 19: M.p. 282-283° C. 1 H NMR (400M, CDCl 3 ): δ 8.55 (d, J=7.6 Hz, 1H), 8.39 (d, J=8.0 Hz, 1H), 8.15 (d, J=7.6 Hz, 1H), 7.92 (t, J=8.0 Hz, 1H), 7.45 (d, J=8.0 Hz, 2H), 7.13 (d, J=8.0 Hz, 2H), 7.02 (d, J=8.0 Hz, 1H), 2.75 (m, 1H), 1.69 (m, 2H), 1.29 (d, J=8.0 Hz, 3H), 0.92 (t, J=8.0 Hz, 3H). TOF MS EI + : C 25 H 18 N 2 OS, (m/z): calcd for 394.1140, found 394.1137.
EXAMPLE 17
Synthesis and Characterization of 3-(4-Isopropyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (20)
[0133]
[0134] 0.69 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 1.82 g 4-Isopropyl-benzenethiol were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 3 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 50%.
[0135] Characterization of 3-(4-Isopropyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (20): M.p.214-215° C. 1 H NMR (400 MHz, CDCl 3 ): δ 8.57 (d, J=8.4 Hz, 1H), 8.47 (d, J=8.4 Hz, 2H), 7.92 (d, J=8.0 Hz, 1H), 7.87 (d, J=8.0 Hz, 1H), 7.61 (t, J=8.0 Hz, 1H), 7.31 (t, J=9.2 Hz, 2H), 7.22 (d, J=8.4 Hz, 1H), 2.87 (m, 1H), 1.2 (d, J=8.0 Hz, 6H). TOF MS (EI + ): C 24 H 16 N 2 OS, (m/z): calcd for 380.0983, found 380.0985.
EXAMPLE 18
Synthesis and Characterization of 3-(4-sec-Butyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (21)
[0136]
[0137] 0.69 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 1.99 g 4-sec-Butyl-benzenethiol were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 3 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 42%.
[0138] Characterization of 3-(4-sec-Butyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (21): M.p. 245-246° C. 1 H NMR (400M, CDCl 3 ): δ 8.85 (d, J=8.0 Hz, 1H), 8.22 (d, J=8.0 Hz, 1H), 8.07 (d, J=8.4 Hz, 1H), 7.68 (t, J=8.0 Hz, 1H), 7.53 (d, J=8.0 Hz, 2H), 7.41 (d, J=8.4 Hz, 2H), 7.12 (d, J=8.4 Hz, 1H), 2.55 (m, 1H), 1.55 (m, 2H),1.31 (d, J=8.0 Hz, 3H), 0.89 (t, J=8.0 Hz, 3H),. TOF MS (EI + ): C 25 H 18 N 2 OS, (m/z): calcd for 394.1140, found 394.1137.
EXAMPLE 19
Synthesis and Characterization of 6-(4-Isopropyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (22)
[0139]
[0140] 0.69 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 1.82 g 4-Isopropyl-benzenethiol were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 3 h. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 32%.
[0141] Characterization of 6-(4-Isopropyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (22): M.p. 257-259° C. 1H NMR (400M, CDCl 3 ): δ 8.32 (d, J=8.8 Hz, 1H), 8.11 (d, J=8.8 Hz, 1H), 7.95 (d, J=8.8 Hz, 1H), 7.85 (d, J=8.0 Hz, 1H), 7.57 (d, J=8.4 Hz, 2H), 7.50 (t, J=8.4 Hz, 1H), 7.06 (d, J=8.4 Hz, 2H), 2.87 (m, 1H), 1.2 (d, J=8.0 Hz, 6H). TOF MS EI + : C 24 H 16 N 2 OS, (m/z) calcd for 380.0983, found 380.0987.
EXAMPLE 20
Synthesis and Characterization of 3,6-Bis-(4-isopropyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (23)
[0142]
[0143] 1.0 g 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile and 2.9 g 4-sec-Butyl-benzenethiol were dissolved in acetonitrile (50 ml), and then stirred at room temperature for 30 hours. The solvent was reduced in vacuo and the residue was purified by normal phase column chromatography on silica gel with a yield of 20%.
[0144] Characterization of 3,6-Bis-(4-isopropyl-phenylsulfanyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (23): M.p. 268-269° C. 1 H NMR (400M, CDCl 3 ): δ 8.12 (d, J=8.8 Hz, 1H), 7.60 (d, J=8.8 Hz, 1H), 7.51 (d, J=8.0 Hz, 4H), 7.48 (d, J=8.8 Hz, 1H), 7.23 (d, J=8.8 Hz, 1H), 7.08 (d, J=8.0 Hz, 4H), 2.55 (m, 2H), 1.52 (m, 4H), 1.25 (d, J=8.0 Hz, 6H), 0.78 (t, J=8.0 Hz, 6H). TOF MS EI 30 : C 35 H 30 N 2 OS 2 , (m/z): calcd for 558.1800, found 558.1803.
EXAMPLE 21
Synthesis and Characterization of 3-(4-Aminomethyl-benzoyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (24) and 4-(4-Aminomethyl-benzoyl)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (25)
[0145]
[0146] 0.95 g 5-(4-Aminomethyl-benzoyl)-acenaphthylene-1,2-dione and 0.33 g malononitrile were dissolved in dichloromethane, and then mixture was applied to a gel silica column and eluted quickly. After all the mixture passed through, the column was spun dry. Dark red solid was obtained with a weight of 0.93 g and a yield of 85%. 0.08 g of K 2 CO 3 and 20 mL of acetonitrile were added into 0.73 g of the dark red solid. The mixture was heated and refluxed for 3 hours. After the reaction finished, the reaction solution was spun dry and separated by chromatographic column (CH 2 Cl 2 : petroleum ether=2:1) to obtain dark red solid. The isomer ratio is 1:0.2 tested by nuclear magnetic resonance. The resulting isomers were separated by liquid phase separation to obtain two isomers.
[0147] Characterization of 24: M.p. 289-290° C. 1 H NMR (400M, CDCl 3 ): δ 8.96 (dd, J=8.8 Hz, 1H), 8.73 (d, J=8.8 Hz, 1H), 8.15 (d, J=8.4 Hz, 1H), 8.08 (t, J=8.8 Hz, 1H), 7.93 (d, J=8.4 Hz, 1H), 7.69 (d, J=8.4 Hz, 2H), 7.35 (d, J=8.4 Hz, 2H), 6.32 (br, 2H), 4.36 (s, 2H). TOF MS EI + : C 23 H 13 N 3 O 2 , (m/z): calcd for 363.1008, found 363.1009.
[0148] Characterization of 25: M.p.>300° C.: 1 H NMR (400M, CDCl 3 ): δ 8.85 (dd, J=8.8 Hz, 1H), 8.70 (d, J=8.8 Hz, 1H), 8.10 (d, J=8.4 Hz, 1H), 7.98 (t, J=8.8 Hz, 1H), 7.86 (d, J=8.4 Hz, 1H), 7.59 (d, J=8.4 Hz, 2H), 7.50 (d, J=8.4 Hz, 2H), 6.08 (br, 2H), 4.36 (s, 2H). TOF MS EI + : C 23 H 13 N 3 O 2 , (m/z): calcd for 363.1008, found 363.1005.
EXAMPLE 22
Synthesis and Characterization of 3-Hexyloxy-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid (26)
[0149]
[0150] 60 ml of concentrated sulfuric acid or 25 ml of fuming sulfuric acid was added into a 50 ml single neck flask. 0.05 mol of 3-Hexyloxy -8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile was added thereinto in batches at a temperature of 0-5° C. within 1 hour. After that, the reaction was carried out for another 18 hours at room temperature, and the resulting reaction mixture was viscous, deep, brownish red. Then the resulting mixture was dropped slowly into crushed ice and stirred acutely. After that, the mixture was stood and filtered. The filter cake was washed with a great quantity of water until it became neutral. The filter cake was dried to obtain the product with a yield of 90%.
[0151] Characterization of 3-Hexyloxy-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid (26): M.p. 235-237° C. 1 H NMR (400M, CDCl 3 ): δ 11.0 (s, 1H), 8.55 (d, J=8.0 Hz, 1H), 8.45 (d, J=8.0 Hz, 1H), 8.01 (t, J=8.0 Hz, 1H), 7.71 (d, J=8.4 Hz,1H), 6.561 (d, J=8.4 Hz, 1H), 4.10 (t, J=7.6 Hz, 2H), 1.75 (m, J=7.6 Hz, 2H), 1.43 (m, 2H), 1.31 (m, 2H), 1.29 (m, 2H), 0.89 (t, J=7.6 Hz, 3H); TOF MS EI + : C 21 H 19 NO 4 , (m/z): calcd for 349.1314, found 349.1316.
EXAMPLE 23
Synthesis and Characterization of 3-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid methyl ester (27)
[0152]
[0153] 3.78 g of 3-4-Isobutyl-phenoxy -8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid, 50 ml of acetonitrile as solvent, 2.76 g of K 2 CO 3 as deacid reagent and iodomethane over ten times were added into a 100 ml single neck flask in sequence. Under nitrogen protection, the mixture was heated up to 42° C. and the reaction was lasted for 18 hours. The acetonitrile was vaporized out under decompressed condition, and the reactant was fully dissolved by addition of dichloromethane. After filtration, the filtrate was spun dry to obtain a yellow brown crude product. The deep yellow product was obtained by column chromatographic separation with gel silica with the yield 85%.
[0154] Characterization of 3-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid methyl ester (27): M.p. 215-216° C. 1 H NMR (400M, CDCl 3 ): δ 8.45 (d, J=8.0 Hz, 1H), 8.35 (d, J=8.0 Hz, 1H), 7.85 (t, J=8.0 Hz, 1H), 7.68 (d, J=8.4 Hz, 1H), 7.36 (d, J=8.8 Hz, 2H), 7.23 (d, J=8.8 Hz, 2H), 6.50 (d, J=8.4 Hz, 1H), 2.45 (d, J=8.4 Hz, 2H), 1.52 (m, 2H), 1.25 (d, J=8.4 Hz, 3H), 0.93 (t, J=8.4 Hz, 3H). TOF MS EI + : C 26 H 21 N 3 O 3 S, (m/z): calcd for 427.1242, found 427.1245.
EXAMPLE 24
Synthesis and Characterization of 3-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid butylamide (28)
[0155]
[0156] 3.97 g of 3-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid, 50 ml of DMF as solvent, 0.15 mL of triethylamine, 1.63 g of (EtO) 2 P(═O)CN and n-butylamide over ten times were added into a 100 ml single neck flask in sequence and reacted for 1 hour at room temperature. Then yellow solid was obtained after the reaction finished. The yield was 85%.
[0157] Characterization of 3-(4-Isobutyl-phenoxy)-8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carboxylic acid butylamide (28): M.p. 247° C. 1 H NMR (400M, CDCl 3 ): δ 8.49 (d, J=8.0 Hz, 1H), 8.40 (d, J=8.0 Hz, 1H), 7.83 (t, J=8.0 Hz, 1H), 7.66 (d, J=8.0 Hz, 1H), 7.46 (d, J=8.4 Hz, 2H), 7.31 (d, J=8.4 Hz, 2H), 6.63 (d, J=8.0 Hz, 1H), 5.53 (br, 1H), 3.21(t, J=8.0 Hz, 2H), 2.53 (m, 1H), 1.52-1.50 (m, 7H), 1.25-1.32 (m, 5H), 0.91 (t, J=8.0 Hz, 3H). TOF MS EI + : C 25 H 19 N 2 O 3 , (m/z): calcd for 395.1396, found 395.1394.
Part II: Detection of the Physicochemical Bioactivity of the Bcl-2 Inhibitors
EXAMPLE 13
Detection of BH3 analogous degree of the compounds by ELISA assay
[0158] The present inventors used fluorescence polarization assay to detect the bonding force between the protein and the compounds in a previous study (PCT/CN2010/075521). The data of the following studies showed that the fluorescent tag FAM was interfered by the compounds because of the autofluorescence in the fluorescence polarization assay. ELISA assay was used to detect the bonding force between the compounds and the protein in this application.
[0159] Biotinylated Bim peptide was diluted to 0.09 μg/mL in SuperBlock blocking buffer in PBS and incubated for 1.5 h in 96-well microtiter plates already coated with streptavidin to allow the formation of the complex between Biotin-Bim and streptavidin. All incubations were performed at room temperature unless otherwise noted. Each inhibitor was first dissolved in pure DMSO to obtain a 10 mM stock solution. For each tested inhibitor, different concentrations of the inhibitor were incubated with 20 nM His-tagged Mcl-1 protein in PBS for 1 h with a final DMSO concentration of 4%. The plates were washed three times with PBS containing 0.05% Tween-20. The inhibitor and protein mixture (100 μL) were transferred to the plate containing the biotin-Bim/streptavidin complex and incubated for 2 h. The plate was then washed as before and mouse anti-His antibody that conjugated with horseradish peroxidase was added into the wells and incubated for 1 h. The plate was then washed with PBS containing 0.05% Tween-20. Finally, TMB was added to each well; the enzymatic reaction was stopped after 30 min by addition of H 2 SO 4 (100 μL, 2M). Absorbances were measured with a TECAN GENios (Swiss, TECAN) microplate reader using a wavelength of 450 nm. Three independent experiments were performed with each inhibitor to calculate average IC 50 value and standard deviation (SD).
[0160] The BH3 analogous degrees of other 11 compounds were detected by using the experimental method as described above. The protein binding constant (binding constant in table 1) between them and Bcl-2 and Mcl-1 proteins were also on nM grade. The detailed results were shown in table 1.
[0000]
TABLE 1
Bcl-2 binding
Mcl-1 binding
Compound
constants (nM)
constants (nM)
1
142
49
2
28
25
3
8
14
4
35
95
5
65
125
6
45
66
7
66
14
8
6
4
9
63
16
10
17
5
11
112
46
12
9
15
[0161] The binding capacities between the compounds and protein in this application are significantly greater than the binding capacities in previous studies about a series of acenaphtho heterocyclic compounds of 8-oxo-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (WO2010054575A1; CN101423491A; J. Med. Chem, 2011, 54, 1101-1105; E J. Med Chem, doi: 10.1016/j.ejmech. 2011.05.062). Spss software was used to do statistical analysis, the results showed that p <0.05. This result indicated that the Bcl-2 protein binding constant of a series of compounds in this application were significantly lower than the corresponding value of the series acenaphtho heterocyclic compounds which have been disclosed in the prior studies under existing technical conditions. The Mcl-1 protein binding constant of a series of compounds in this application were significantly lower than the corresponding value of the acenaphtho heterocyclic compounds which have been disclosed in the prior studies under existing technical conditions.
EXAMPLE 14
Detection of BH3 analogous degree of the compounds by fluorescence polarization assay
[0162] A Bid BH3 peptide (amino acids: 79-99: QEDIIRNIARHLAQVGDSMDR) having 21 amino acids was synthesized and marked with 6-carboxyfluorescein N-succinimidyl ester (FAM) as fluorescent tag (FAM-Bid) at the N-terminal. The reaction system used in the competitive binding experiment was GST-Bcl-2 protein (40 nM) or Mcl-1 protein, which was dissolved in the reaction buffer (100 mM K 3 PO 4 , pH 7.5; 100 μg/ml bovine γ albumin; 0.02% sodium azide) together with FAM-Bid polypeptide (5 nM). In a 96-well plate, 1004 of the reaction system was added into each well. Then 1 μL different concentration of compound 13 mother solution to be detected dissolved in DMSO was added there into until the final concentration met the experimental design requirements. Meanwhile, two control groups were established, one with the reaction system only containing Bcl-2 or Mcl-1 and FAM-Bid (equivalent to 0% inhibition rate), the other with the reaction system only containing FAM-Bid peptide. After 4 hours of incubation, the 96-well plate was detected by enzyme-labelled meter. The fluorescent polarization value (mP) was tested at 485 nm emission wavelength excited and generated by 530 nm wavelength. K i value was deduced according to calculation formula. The experimental results were shown in FIGS. 3 and 4 . The competitive binding constant between the compound and Bcl-2 was 158 nM. The competitive binding constant between the compound and Mcl-1 was 24 nM.
[0163] The BH3 analogous degrees of other 12 compounds were detected by using the experimental method as described above. The protein binding constant (binding constant in table 2) between them and Bcl-2 and Mcl-1 proteins were also on nM grade. The detailed results were shown in table2.
[0000]
TABLE 2
Bcl-2 binding
Mcl-1 binding
Compound
constants (nM)
constants (nM)
13
158
24
15
140
12
16
210
56
17
20
85
18
120
8
19
23
85
20
23
57
21
12
65
22
9
85
23
540
25
25
115
135
26
105
85
27
86
75
EXAMPLE 15
Detection of the BH3 analogous degree of the compounds by intracellular fluorescence polarization energy transfer (FRET)
[0164] 2 μg of Bcl-2-CFP and Bax-YFP plasmids were transfected separately or simultaneously into Hela cells by using calcium phosphate coprecipitation method, 24 hours later, the cells were inoculated in a 6-well plate (2×10 5 cells/well), and the compound 1 to be detected dissolved in DMSO was added there into until the final concentration (2, 5, 10 and 15 μM) was achieved. 24 hours later (please refer to FIG. 5 ); the cells were washed with PBS for three times. The fluorescence value was detected by GENIOS fluorescence enzyme-labelled meter (TECAN, Swiss). In time-dependent experiment, the transfected cells were inoculated in a 6-well plate, after that, 40 μM of the compound was added thereinto. 3, 6 and 24 hours later ( FIG. 6 ), the fluorescence intensities were detected by plate reader. As for the cell group in which only Bcl-2-CFP plasmid was transfected, the values at 475 nm emission wave length and 433 nm excitation wave length were recorded. As for the cell group in which only Bax-YFP plasmid was transfected, the values at 527 nm emission wave length and 505 nm excitation wave length were recorded. As for the cell group in which Bcl-2-CFP and Bax-YFP plasmids were co-transfected, the values at 527 nm and 475 emission wave lengths and 433 nm excitation wave length were recorded. The ratio of fluorescence intensity at 527 nm and 475 nm emission wave lengths was FRET. The FRET for the control group in which the plasmid was solely transfected was set as 1.0. This meant that the fluorescence polarization energy transfer for two proteins did not occur. In the cotransfected cells, the FRET increased up to 2.0 due to the interaction of Bcl-2 protein and Bax protein, and that the interference to the interaction between the two proteins increased and FRET decreased with the increase of the drug concentration and time. The cellular vitality was detected by MTT method. The experimental results were shown in FIGS. 5 and 6 . When the concentration of the compound reached 1 μM, the interaction between Bcl-2 and Bax can be interfered after 2 hours, and the results appeared concentration-time dependent trend.
[0165] Other 24 compounds were detected by the same experimental method as described above, it has been experimentally proved that all the compounds had the function of simulating BH3-only protein in cells and can obviously interfere with the interaction between Bcl-2 and Bax under different concentration and time conditions. The detailed results were shown in table 3.
[0166] Wherein the concentration and time meant that the detected compound interfered with the interaction between Bcl-2 and Bax at the concentration for the time period.
[0000]
TABLE 3
Compound
Doses (μM)
Time (h)
1
1.0
2
2
0.4
3
3
0.2
2
4
1.0
5
5
2.0
6
6
2.0
5
7
0.3
3
8
0.1
1
9
0.4
2
10
0.1
2
11
0.3
2
12
0.2
1
13
0.5
4
15
0.5
4
16
0.5
3
17
0.1
2
18
0.5
4
19
0.3
3
20
0.2
2
21
0.2
2
22
0.5
2
23
1.0
2
25
0.6
4
26
0.5
5
27
0.3
3
EXAMPLE 16
Detection of the BH3 analogous degree of the compounds by co-localization between Bax protein and chondriosome
[0167] 5 μg of Bax-YFP plasmid was transfected into MCF-7 cells by using calcium phosphate coprecipitation method, 24 hours later, the cells were inoculated in a 6-well plate (0.2×10 6 cells/well), and 10 μM of the compound 1 to be detected was added thereinto. 6 hours later, the cells were washed with PBS and hatched away from light with 50 nM Mito Tracker Red CMXRos (chondriosome specific probes; red) for 10 minutes. Then the cells were washed with PBS for three times, and the fluorescent image was scanned with Radiance2000 laser confocal microscopy (Bio-Rad, USA). Meanwhile, dual channel scanning was carried out, one channel was used to scan the green fluorescence of Bax-YFP, and the other channel was used to scan the red fluorescence of the CMXRos probe for indicating the chondriosome. The co-localization circumstance was displayed by superimposing the two channel images. When the Bax protein was localized on the chondriosome, the green and red fluorescence was superimposed into orange, as shown in FIG. 7 . FIG. 8 for comparison showed that the BAX cannot be drived to shift towards the chondriosome, i.e., the co-localization failed.
[0168] Other 24 compounds were detected by the same experimental method as described above. The results showed that all the compounds had the function of driving the BAX to shift towards the chondriosome, which indicated that they all had the function of simulating the BH3-only protein in cells. The detailed results were shown in table 4. Wherein the concentration and time meant that the detected compound simulated the BH3-only protein and driven the BAX to shift towards the chondriosome at the concentration for the time period.
[0000]
TABLE 4
Compound
Doses (μM)
Time (h)
1
1.0
3
2
0.5
3
3
0.2
2
4
3.0
4
5
5.0
5
6
4.0
4
7
0.5
3
8
0.1
1
9
0.6
3
10
0.2
1
11
0.9
3
12
0.3
2
13
5.0
4
15
5.0
3
16
4.0
3
17
1.0
1
18
5.0
4
19
3.0
3
20
5.0
3
21
2.0
2
22
5.0
3
23
1.0
3
25
6.0
4
26
5.0
5
27
2.0
3
EXAMPLE 17
Experimental testing for the property of the BH3 analogues by the cytotoxicity of the compounds depending on BAX/BAK
[0169] 3 μg of BAX/BAK interfering plasmid was transfected into MCF-7 cells by using calcium phosphate coprecipitation method, 24 hours later, the cells were collected. The expressions after the BAX and BAK proteins interfered with RNA was detected by Western, and the cell groups without plasmid transfection were treated similarly and were set as the control group. The transfected cells were inoculated in a 96-well plate (1×10 5 cells/well), the control experiment of the cell group without plasmid transfection was carried out in parallel. The compound 1 to be detected was added thereinto according to the concentration gradient designed before the experiment. 48 hours later, the cellular vitality was detected by MTT. The experimental results were shown in FIG. 9 , Gossypol as nonspecific BH3 analogue was treated in parallel. The results showed that compound 1 had cytotoxicity of absolute dependence on BAX/BAK.
[0170] Other 24 compounds were also detected by the same experimental method as described above, the differences of IC 50 values between the transfected cells and the without plasmid transfection cells were compared. Results showed that the detected compounds also had the characteristics of absolute dependence on BAX/BAK.
[0000]
TABLE 5
IC 50 value in untransfected
IC 50 value in transfected
Compound
cells (μM)
cells (μM)
1
4
>50
2
3.5
>50
3
3
>50
4
5.6
>50
5
6.5
>50
6
4.0
>50
7
1.2
>50
8
1.0
>50
9
1.3
>50
10
0.5
>50
11
4.2
>50
12
2.9
>50
13
7.5
>50
15
7.1
>50
16
8.5
>50
17
2
>50
18
6.8
>50
19
2.2
>50
20
2.1
>50
21
1.5
>50
22
1.2
>50
23
15
>50
25
6.5
>50
26
6.2
>50
27
5.6
>50
EXAMPLE 18
Detection of the inhibition of the compounds against Md-1 and Bcl-2 by Western blotting
[0171] (1) The cell sample was collected and cracked with 1×10 6 /50 μl cell lysis solution (62.5 mM Tris-HCL pH 6.8; 2%SDS; 10% glycerol; 50 mM DTT; 0.01% bromphenol blue) at low temperature, then the solution was centrifuged and the protein supernatant was collected. The sample was boiled at 100° C. for 5 minutes and then was separated by electrophoresis on 12% SDS-PAGE and transferred. The interest protein was detected by the corresponding antibody. The expression of the interest protein in the cells was detected by horseradish peroxidase-labeled secondary antibodies in combination with ECL coloration method. The inhibition of the compound 1 to be detected against Mcl-1 and Bcl-2 was separately shown in FIG. 10 and FIG. 11 . It can be seen from the figures that the Bcl-2 and Mcl-1 protein bands gradually became light as the time for the compound to be detected acting on the tumor cells went. This meant that the compound had the inhibition against these two proteins. The concentration of the protein bands in the Western images were carried out semiquantitative analysis and normalization treatment with KODAK Gel Logic 1500 imaging system software. The concentration of the protein bands was shown in FIG. 12 and FIG. 13 .
[0172] The following 18 compounds were also detected by using the same method as described above, it can be seen that they all had the inhibition against Bcl-2 and Mcl-1 proteins. Bcl-2 and Mcl-1 were inhibited by these compounds and the results of the semiquantitative analysis were shown in Table 6 and 7:
[0000]
TABLE 6
Compound
Control
6 h
12 h
18 h
24 h
1
1
0.99
0.99
0.58
0.21
2
1
0.99
0.99
0.50
0.19
3
1
0.99
0.99
0.49
0.18
7
1
0.99
0.99
0.51
0.20
8
1
0.99
0.99
0.42
0.10
9
1
0.99
0.99
0.49
0.20
10
1
0.99
0.99
0.45
0.12
11
1
0.99
0.99
0.57
0.22
12
1
0.99
0.99
0.45
0.16
13
1
0.99
0.99
0.42
0.14
15
1
0.99
0.99
0.39
0.12
17
1
0.99
0.99
0.58
0.11
18
1
0.99
0.99
0.36
0.10
20
1
0.99
0.99
0.50
0.23
21
1
0.99
0.99
0.49
0.18
22
1
0.99
0.99
0.60
0.37
23
1
0.99
0.99
0.70
0.41
27
1
0.99
0.99
0.57
0.29
[0000]
TABLE 7
Compound
Control
2 h
6 h
1
1
0.79
0.35
2
1
0.70
0.31
3
1
0.65
0.29
7
1
0.68
0.32
8
1
0.52
0.22
9
1
0.60
0.29
10
1
0.53
0.21
11
1
0.70
0.34
12
1
0.66
0.28
13
1
0.79
0.29
15
1
0.69
0.42
17
1
0.65
0.37
18
1
0.66
0.39
20
1
0.60
0.29
21
1
0.59
0.28
22
1
0.68
0.49
23
1
0.60
0.59
27
1
0.57
0.29 | The present invention relates to acenaphtho heterocyclic compounds and their uses in manufacturing the BH3 mimetics as Bcl-2-like protein inhibitors. Structures are shown in the following:
Statistical analysis of their bio-activities showed these compounds exhibit better BH3 mimicking property than the reported compounds. These compounds can simulate BH3-only protein, competitively bind and antagonizing Bcl-2 and Mcl-1 proteins in vitro and in cells, and then induce apoptosis. Therefore, they all can be used in the manufactures of anticancer compounds. | 2 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a springing or suspension construction for making mattresses and the like.
[0002] As is known, springing or suspension constructions conventionally used for making paddings and mattresses are usually made starting from spring elements which, in their most evolved patterns, provide to use independent bagged-in springs, made of a metal material, and, in particular, of a piano steel and the like.
[0003] Such a pattern allows to provide an anatomically proper lying for a user, even from a moisture standpoint, since, because of a bellow sort of effect, a good air exchange is achieved.
[0004] However, the above mentioned approach has the drawback that the inner structure of the springs is made of a steel material, thereby providing an electromagnetic wave receiving and reflecting mass, affected by a comparatively high amount of electromagnetical waves generated by TV sets cellular phones, computers, telecontrol devices, high voltage apparatus, radars, artificial satellites and so on, as well as other electric apparatus.
[0005] In such a condition, the human body, in particular during a rest period thereof, is immersed in an environment which is objectable from a health standpoint.
SUMMARY OF THE INVENTION
[0006] Accordingly, the aim of the present invention is to overcome the above mentioned problem, by providing a springing or suspension construction, in particular for making mattresses and the like, allowing to nearly fully eliminate any metal element, thereby overcoming the above mentioned negative effects related to the electromagnetic wave reception and reflection.
[0007] Within the scope of the above mentioned aim, a main object of the invention is to provide such a springing or suspension construction, specifically designed for making mattresses and the like, which allows to use an independent springing at several regions of the mattress, while preserving all the positive features of the bagged-in spring elements, without having their drawbacks.
[0008] Another object of the present invention is to provide such a springing or suspension construction which, owing to its peculiar designing features, is very reliable and safe in operation.
[0009] Yet another object of the present invention is to provide such a springing construction, for making mattresses and the like, which can be easily made and which, moreover, is very competitive from a mere economic standpoint.
[0010] According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a springing construction for making mattresses and the like, characterized in that said springing construction comprises a plurality of resilient modular elements, having a central coupling body for coupling to locating bars which extends substantially parallel to a mattress lying plane, said central body being associated with a central springing element adjoining, on opposite sides of the locating bars lying plane, springing side elements, said modular elements being resiliently yieldable along a direction substantially perpendicular to the mattress lying plane.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of a preferred, though not exclusive, embodiment of a springing construction, specifically designed for making mattresses and the like, which is illustrated, by way of an indicative, but not limitative, example in the accompanying drawings, where:
[0012] FIG. 1 is a schematic perspective view showing a resiliently yieldable or yielding modular element;
[0013] FIG. 2 is a further schematic perspective view showing a plurality of modular elements as assembled with one another;
[0014] FIG. 3 is a further exploded perspective view showing a detail of a mattress;
[0015] FIG. 4 is a further perspective, partially broken away view, showing a detail of a mattress;
[0016] FIG. 5 is a schematic top plan view showing the subject mattress;
[0017] FIG. 6 shows the subject mattress, as cross-sectioned along a longitudinal plane perpendicular to the mattress lying plane;
[0018] FIG. 7 is an elevation view showing a resiliently yielding resilient modular element according to a further aspect of the invention, having sleeve elements including a quadrangular cross-section;
[0019] FIG. 8 is yet another exploded perspective view showing the resiliently yieldable or yielding modular element of FIG. 7 , and a locating bar with a spot fixation system;
[0020] FIG. 9 is a view similar to FIG. 8 , but showing the locating bar associated with the resilient modular element;
[0021] FIG. 10 is a further exploded perspective view showing the resilient modular element of FIG. 9 and a locating bar with a fixed-joint type or of attachment system;
[0022] FIG. 11 is a schematic view similar to FIG. 10 , but showing the locating bar associated with the resilient modular element;
[0023] FIG. 12 is a further schematic perspective view showing a plurality of modular elements of the type shown in FIG. 7 , and assembled with one another;
[0024] FIG. 13 is a further exploded perspective view showing a detail of a mattress including a plurality of modular elements of the type shown in FIG. 7 ; and
[0025] FIG. 14 shows the mattress of FIG. 13 , as cross-sectioned along a longitudinal cross-section plane perpendicular to the lying plane of the mattress.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] With reference to the number references of the above mentioned figures, the springing or suspension construction, specifically designed for making mattresses and the like, which has been generally indicated by the reference number 1 , comprises a plurality of resilient or resiliently yieldable or yielding modular elements 2 , which are made of a plastics material and, in particular, of a resilient plastics material such as polyurethane, hytrel and the like.
[0027] Each said modular element 2 , as shown in FIG. 1 , has a central coupling body 3 , made of a central sheet element 4 ending with a pair of projecting sleeve elements 5 , thereby operating as a spacer.
[0028] Said sleeve elements 5 , in particular, are designed to receive therein locating bars 6 , lying in a plane parallel to the mattress lying plane and being arranged substantially transversally of the longitudinal extension of the mattress.
[0029] Said bars 6 , having end plug elements 7 , are threaded into the sleeve elements 5 , thereby allowing the resilient modular elements to be coupled so as to practically provide a quincuncial pattern.
[0030] To said central body 3 is coupled a central springing element 10 which, advantageously, is patterned as an elongated eight element, with the central portion 11 rigid with the sheet element and with closed portions encompassing the sleeve members 5 thereby being spaced from the latter.
[0031] A plurality of springing side elements, generally indicated by the reference number 20 , are arranged in an adjoining relationship with the central springing element, said side springing elements also having an elongated- 8 pattern, and being arranged on opposite sides of the plane defined by the coupling bars 6 .
[0032] More specifically, said side springing elements have flat portions 21 , on their outer parts, defining a broad glueing flat zone, for glueing, by a glue layer 30 , conventional padding and coating layers, which have been generally indicated in the drawings by the reference number 31 , and are made for completing the mattress inside the closure sheath 32 thereof.
[0033] At the perimetrical regions of the mattress 40 are moreover provided perimetrical blocks 41 , made of a foamed plastics material, such as foamed polyurethane, latex foam and the like, defining the mattress contour and providing a finishing pattern for the springing construction housing region.
[0034] FIGS. 7 to 14 show further embodiments of the invention, in which the subject springing construction comprises a plurality of resilient modular elements 102 having a modified pattern from the modular elements 2 as thereinabove disclosed, but still made of a plastics material and, in particular, of a resilient thermoplastics material such as polyurethane, hytrel and the like.
[0035] As shown in FIG. 7 , each said modular element 102 comprises a central coupling body 103 , constituted by a central sheet element 104 ending with a pair of sleeve elements 105 having a quadrangular cross-section and substantially the same width as the modular element body.
[0036] Locating bars 106 are housed in said sleeve elements 105 , said locating bars lying in a plane which is substantially parallel to the mattress lying plane and being arranged substantially transversely of the longitudinal extension of the mattress.
[0037] In the embodiment shown in FIGS. 8 and 9 , said locating bars 106 are engaged in said sleeve elements 105 through an interposition of quadrangular bushings 107 , having a cross section which is substantially equal to the sleeve element cross section, and being used for applying attachment or fixing-clamping means for said locating bars, preferably comprising a plurality of fixing spots 109 or other suitable fixing elements.
[0038] According to a further embodiment, shown in FIGS. 10 and 11 , the connection system for coupling the modular elements comprises connection small rods 206 having a cross-section which substantially corresponds to a half of the sleeve element 105 cross section, thereby allowing the end portions of two rods 206 to be easily engaged in said sleeve elements.
[0039] In particular, said rods 206 have enlarged end portions 209 which can be resiliently deformed through a notch, thereby allowing the engaging of said rods into said sleeve elements 105 , while preventing the rods from being disengaged or unthreaded from the latter.
[0040] The modular element 102 comprises moreover a central springing element 110 , coupled to the central body 103 and which has advantageously an elongated-8 pattern, with the central portion 111 being integral or rigid with the sheet element 104 and with closed portions encompassing the sleeve elements 105 , while being properly spaced therefrom.
[0041] The sleeve elements 105 are moreover connected to the central springing element 110 by stabilizing buttress elements 112 .
[0042] Adjoining the central springing element are provided side springing elements, indicated by the reference number 120 , which also have an elongated-8 pattern and are arranged on opposite sides of the plane defined by the connecting rods or bars 106 .
[0043] Said side springing elements, in particular, have flat portions 121 , on their outer walls, allowing to define a broad flat region for glueing conventional padding and coating layers, made for finishing the mattress inside the closure sheath or lining thereof.
[0044] As shown, the flat portions 121 are advantageously coupled by a reinforcing lug 112 .
[0045] The mattress, generally indicated by the reference number 140 , comprises, as in the above disclosed embodiment thereof, conventional padding and coating layers, generally indicated by the reference number 131 and made for finishing the mattress inside the closure lining thereof.
[0046] At the perimetrical regions of the mattress 140 are moreover provided perimetrical blocks 141 , made of a foamed plastic material, such as foamed polyurethane, latex foam and the like, defining the mattress contour and providing a proper finishing of the springing construction housing region.
[0047] By the above disclosed device it is possible to provide a very efficient springing or suspension construction, which can be assembled in a very quick manner and which does not use metal elements, and, moreover, is adapted to anatomically support a human body.
[0048] From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects.
[0049] In particular, the fact is to be pointed out that the invention as provided has springing construction based on the use of a modular element which can be easily made, and which is very efficient from an operating standpoint and can be furthermore assembled in a very quick manner.
[0050] The invention, as disclosed, is susceptible to several modifications and variations, all coming within the scope of the invention.
[0051] Moreover, all the constructional details can be replaced by other technically equivalent elements. | Springing construction for making mattresses where a plurality of resilient modular elements having a central coupling body for coupling to locating bars are extended substantially parallel to the lying plane of the mattress and the central coupling body is associated with a central springing element that adjoins, on opposite sides of the locating bars lying plane, springing side elements, and the modular elements are resiliently yieldable along a direction that is substantially perpendicular to the mattress lying plane. | 0 |
BACKGROUND OF THE INVENTION
The invention relates to investment casting. More particularly, it relates to the investment casting of superalloy turbine engine components.
Investment casting is a commonly used technique for forming metallic components having complex geometries, especially hollow components, and is used in the fabrication of superalloy gas turbine engine components. The invention is described in respect to the production of particular superalloy castings, however it is understood that the invention is not so limited.
Gas turbine engines are widely used in aircraft propulsion, electric power generation, and ship propulsion. In gas turbine engine applications, efficiency is a prime objective. Improved gas turbine engine efficiency can be obtained by operating at higher temperatures, however current operating temperatures in the turbine section exceed the melting points of the superalloy materials used in turbine components. Consequently, it is a general practice to provide air cooling. Cooling is provided by flowing relatively cool air from the compressor section of the engine through passages in the turbine components to be cooled. Such cooling comes with an associated cost in engine efficiency. Consequently, there is a strong desire to provide enhanced specific cooling, maximizing the amount of cooling benefit obtained from a given amount of cooling air. This may be obtained by the use of fine, precisely located, cooling passageway sections.
The cooling passageway sections may be cast over casting cores. Ceramic casting cores may be formed by molding a mixture of ceramic powder and binder material by injecting the mixture into hardened steel dies. After removal from the dies, the green cores are thermally post-processed to remove the binder and fired to sinter the ceramic powder together. The trend toward finer cooling features has taxed core manufacturing techniques. The fine features may be difficult to manufacture and/or, once manufactured, may prove fragile. Commonly-assigned U.S. Pat. No. 6,637,500 of Shah et al. and U.S. Pat. No. 6,929,054 of Beals et al (the disclosures of which are incorporated by reference herein as if set forth at length) disclose use of ceramic and refractory metal core combinations.
FIG. 1 shows a trailing edge portion of a turbine airfoil 20 as cast within a shell 22 . For casting the internal passageways, the shell contains a core assembly. The exemplary core assembly includes a ceramic feed core having spanwise legs 30 , 32 , and 34 for casting associated passageway legs. The leg 34 casts a trailing spanwise passageway 36 . The core assembly also includes metallic cores, of which cores 40 , 42 , and 44 are shown. The exemplary metallic cores are formed of refractory metal sheet stock. The core 40 forms a pressure side outlet circuit, the core 42 forms a suction side outlet circuit, and the core 44 forms a trailing edge outlet slot 50 . The outlet slot 50 is fed from the passageway 36 . During core assembly, a leading portion of the core 44 is secured within a mating slot of the trailing leg 34 of the ceramic core. With such a configuration, the transition between the passageway 36 and the outlet slot 50 may be relatively abrupt and may create relatively thick areas 52 and 54 of the pressure and suction side walls.
SUMMARY OF THE INVENTION
One aspect of the invention involves a method for manufacturing an investment casting core from a metallic blank. The blank has a thickness between parallel first and second faces less than a length and width transverse thereto. The blank is locally thinned from at least one of the first and second faces. The blank is through-cut across the thickness.
In various implementations, through-cutting may comprise at least one of laser cutting, liquid jet cutting, and EDM. The thinning may comprise at least one of EDM, ECM, grinding, and mechanical machining. The through-cutting may comprise forming a plurality of through-apertures and a plurality of recesses. After the through-cutting, the blank may be bent to at least partially contract the recesses. The thinning may comprise machining a downstream-tapering portion and leaving a thicker portion downstream of the downstream-tapering portion. The core may be coated. The core may be overmolded with a ceramic core or assembled to a pre-molded ceramic core. The thinning may form a mounting flange by thinning from both the first and second faces. The mounting flange may be overmolded by a ceramic core or inserted into a mating slot of a pre-molded ceramic core.
In an investment casting method, the investment casting core may be at least partially overmolded by a pattern-forming material for forming a pattern. The pattern may be shelled. The pattern-forming material may be removed from the shelled pattern for forming a shell. Molten alloy may be introduced to the shell. The shell may be removed. The method may be used to form a gas turbine engine component. An exemplary component is an airfoil wherein the core forms trailing edge outlet passageways.
Another aspect of the invention involves an investment casting core having a metallic core element and a ceramic core. The metallic core element has a flange extending from a second portion, the second portion thicker than the flange. The ceramic casting core has a slot receiving the flange and slot shoulders abutting shoulders of the second portion. A smooth continuous taper may span a junction between the metallic casting core element and the ceramic casting core. The slot may be pre-molded or formed by overmolding the metallic casting core element.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial streamwise sectional view of a trailing edge portion of a prior art airfoil cast within a ceramic shell.
FIG. 2 is a partial streamwise sectional view of a modified airfoil.
FIG. 3 is a view of a composite core for casting the airfoil of FIG. 2 .
FIG. 4 is a streamwise sectional view of a trailing portion of the composite core of FIG. 3 .
FIG. 5 is a trailing edge view of the composite core of FIG. 3 .
FIG. 6 is a flowchart of a core manufacture process.
FIG. 7 is an end view of a core precursor.
FIG. 8 is an end view of the precursor of FIG. 7 after a first local thinning from a first face.
FIG. 9 is an end view of the precursor of FIG. 8 after additional thinning from the first face and an opposite second face to form a mounting flange.
FIG. 10 is a first face plan view of the precursor of FIG. 9 after a through-cutting.
FIG. 11 is a simplified view of a core formed by bending the precursor of FIG. 10 at a plurality of recesses.
FIG. 12 is a flowchart of an investment casting method.
FIG. 13 is a partial first face view of a first alternate core.
FIG. 14 is a partial first face view of a second alternate core.
FIG. 15 is a partial first face view of a third alternate core.
FIG. 16 is a view of a fourth alternate core.
FIG. 17 is a view of a fifth alternate core.
FIG. 18 is an end view of a sixth alternate core.
FIG. 19 is an end view of a seventh alternate core.
FIG. 20 is an end view of an eighth alternate core.
FIG. 21 is an end view of a ninth alternate core.
FIG. 22 is an end view of a tenth alternate core.
Like reference numbers and designations in the various drawings indicate like elements.
DETAILED DESCRIPTION
FIG. 2 shows a reengineered airfoil 60 which may be based upon the exemplary airfoil 20 . The airfoil 60 has a relatively gently transitioning junction 62 between a trailing feed passageway/cavity 64 and an outlet slot 66 . For example, a leading portion 68 of the slot 66 has a downstream-tapering thickness profile which tends to reduce the peak thickness of the pressure and suction side walls 70 and 72 (thereby reducing part mass, improving part cooling, and reducing resistance to the cooling airflow). Similar smooth transitions have been attempted with purely ceramic cores. However, such purely ceramic cores then suffer breakage problems if fine features of the outlet slot are to be cast.
FIG. 3 shows a portion of a core assembly 80 for casting the passageways 64 and 66 of FIG. 2 . The core 80 includes a ceramic core element/portion 82 and a refractory metal core (RMC) element/portion 84 (also shown in broken lines in FIG. 2 ). For purposes of illustration, remaining portions of the ceramic core element 82 are not shown. Additionally, apertures within both of the elements 82 and 84 are also not shown.
FIG. 4 shows the RMC 84 as including a leading tenon 90 received within a trailing slot or mortise 92 of the ceramic core element 82 . The exemplary tenon and slot are flat with parallel surfaces respectively facing pressure and suction sides of the airfoil. At a root of the tenon 90 , the RMC 84 expands outward with a pair of shoulders 94 and 96 engaging trailing face portions 98 and 100 of the ceramic core element 82 . These mating faces extend outward to respective suction and pressure side faces 102 and 104 of the core assembly 80 . The side faces 102 and 104 smoothly transition between the ceramic core element 82 and the RMC 84 . This junction between RMC and ceramic core falls along a tapering portion 106 . Downstream of tapering portion 106 , the RMC transitions to a straight flat portion 108 and then to a thicker portion 110 wherein the pressure side face 104 protrudes. The exemplary suction side face 102 is smooth along the tapering portion, flat portion, and thicker portion 110 .
In an exemplary sequence 200 of manufacture ( FIG. 6 ) The RMC 84 may be machined from a strip ( FIG. 7 ) having a thickness T, a greater width W, and a yet greater length. In an initial stage of manufacture, gross thickness features may be machined 202 to provide the smooth transition. Specifically, FIG. 8 shows a machining from a pressure side face 120 to define the tapering region 106 and the straight region 108 . The tenon 90 ( FIG. 9 ) is then formed by machining material 204 from both the pressure side face 120 and the suction side face 122 . However, the steps 202 and 204 may easily be combined or further divided.
Additionally, a series of through-cuts are cut 206 . A first group of through-cuts includes recesses 140 ( FIG. 10 ) extending downstream through the tenon 90 and well into the trailing portion 110 . Others of the cuts define apertures 141 , 142 , and 143 for forming posts 150 , 152 , and 153 ( FIG. 2 ) within the outlet slot and apertures 144 for forming trailing dividing walls 154 along the slot outlet. To provide the RMC in the desired arcuate shape corresponding to the airfoil trailing edge, the RMC is bent 208 to partially close the recesses 140 ( FIG. 11 ). The RMC may be coated 210 with a protective coating. Alternatively a coating could be applied pre-assembly. Suitable coating materials include silica, alumina, zirconia, chromia, mullite and hafnia. Preferably, the coefficient of thermal expansion (CTE) of the refractory metal and the coating are similar. Coatings may be applied by any appropriate line-of sight or non-line-of sight technique (e.g., chemical or physical vapor deposition (CVD, PVD) methods, plasma spray methods, electrophoresis, and sol gel methods). Individual layers may typically be 0.1 to 1 mil thick. Layers of Pt, other noble metals, Cr, Si, W, and/or Al, or other non-metallic materials may be applied to the metallic core elements for oxidation protection in combination with a ceramic coating for protection from molten metal erosion and dissolution.
The RMC may be assembled in a die and the ceramic core (e.g., silica-, zircon-, or alumina-based) molded thereover. An exemplary overmolding 212 includes molding the ceramic core 82 over the tenon 90 . The as-molded ceramic material may include a binder. The binder may function to maintain integrity of the molded ceramic material in an unfired green state. Exemplary binders are wax-based. After the overmolding 212 , the preliminary core assembly may be debindered/fired 214 to harden the ceramic (e.g., by heating in an inert atmosphere or vacuum).
FIG. 12 shows an exemplary method 220 for investment casting using the core assembly. Other methods are possible, including a variety of prior art methods and yet-developed methods. The fired core assembly is then overmolded 230 with an easily sacrificed material such as a natural or synthetic wax (e.g., via placing the assembly in a mold and molding the wax around it). There may be multiple such assemblies involved in a given mold.
The overmolded core assembly (or group of assemblies) forms a casting pattern with an exterior shape largely corresponding to the exterior shape of the part to be cast. The pattern may then be assembled 232 to a shelling fixture (e.g., via wax welding between end plates of the fixture). The pattern may then be shelled 234 (e.g., via one or more stages of slurry dipping, slurry spraying, or the like). After the shell is built up, it may be dried 236 . The drying provides the shell with at least sufficient strength or other physical integrity properties to permit subsequent processing. For example, the shell containing the invested core assembly may be disassembled 238 fully or partially from the shelling fixture and then transferred 240 to a dewaxer (e.g., a steam autoclave). In the dewaxer, a steam dewax process 242 removes a major portion of the wax leaving the core assembly secured within the shell. The shell and core assembly will largely form the ultimate mold. However, the dewax process typically leaves a wax or byproduct hydrocarbon residue on the shell interior and core assembly.
After the dewax, the shell is transferred 244 to a furnace (e.g., containing air or other oxidizing atmosphere) in which it is heated 246 to strengthen the shell and remove any remaining wax residue (e.g., by vaporization) and/or converting hydrocarbon residue to carbon. Oxygen in the atmosphere reacts with the carbon to form carbon dioxide. Removal of the carbon is advantageous to reduce or eliminate the formation of detrimental carbides in the metal casting. Removing carbon offers the additional advantage of reducing the potential for clogging the vacuum pumps used in subsequent stages of operation.
The mold may be removed from the atmospheric furnace, allowed to cool, and inspected 248 . The mold may be seeded 250 by placing a metallic seed in the mold to establish the ultimate crystal structure of a directionally solidified (DS) casting or a single-crystal (SX) casting. Nevertheless the present teachings may be applied to other DS and SX casting techniques (e.g., wherein the shell geometry defines a grain selector) or to casting of other microstructures. The mold may be transferred 252 to a casting furnace (e.g., placed atop a chill plate in the furnace). The casting furnace may be pumped down to vacuum 254 or charged with a non-oxidizing atmosphere (e.g., inert gas) to prevent oxidation of the casting alloy. The casting furnace is heated 256 to preheat the mold. This preheating serves two purposes: to further harden and strengthen the shell; and to preheat the shell for the introduction of molten alloy to prevent thermal shock and premature solidification of the alloy.
After preheating and while still under vacuum conditions, the molten alloy is poured 258 into the mold and the mold is allowed to cool to solidify 260 the alloy (e.g., after withdrawal from the furnace hot zone). After solidification, the vacuum may be broken 262 and the chilled mold removed 264 from the casting furnace. The shell may be removed in a deshelling process 266 (e.g., mechanical breaking of the shell).
The core assembly is removed in a decoring process 268 to leave a cast article (e.g., a metallic precursor of the ultimate part). The cast article may be machined 270 , chemically and/or thermally treated 272 and coated 274 to form the ultimate part. Some or all of any machining or chemical or thermal treatment may be performed before the decoring.
FIG. 13 shows an RMC 160 otherwise similar to the RMC 84 but wherein the apertures 141 , 142 , 143 and 144 are replaced by combinations of apertures 162 and wave-like slots 164 . Each of the exemplary slots 164 includes a straight leading portion 166 through the flange, a wave-like (e.g., sinusoidal) portion 168 in the RMC tapering portion and straight region, and a terminal straight portion 170 within the thicker portion. The apertures 162 are interspersed between the slots 164 in phase with the waveform. In the ultimate cast airfoil, adjacent slots 164 may form dividing walls (with passageways in between including posts cast by the apertures 162 ).
FIG. 14 shows an RMC 180 with similar wave-like slots 182 but lacking the apertures 162 . Accordingly, the slots may be at a closer spacing than the slots 164 . FIG. 15 shows an RMC 190 with an array of straight slots 192 in view of the wave-like slots 182 .
FIG. 16 shows an RMC 300 having a spanwise variation in the angle of convergence of its tapering portion 302 . The RMC's tenon 304 and the tapering portion 302 also have as-machined spanwise curvature (e.g., as distinguished from bending at recesses). A trailing portion 306 is also thin and flat (as distinguished from the portion 110 of FIG. 4 and, effectively a continuation of the portion 108 ). For ease of illustration, apertures are not shown.
FIG. 17 an RMC 320 also having spanwise curvature, but wherein the trailing portion 322 has a spanwise variation in thickness (e.g., thicker midspan and tapering toward the inboard and outboard ends). For ease of illustration, apertures are not shown.
FIG. 18 shows an RMC 330 otherwise similar to the RMC 84 but wherein the tapering portion 332 has arrays of dimple-like blind recesses 334 along the pressure and suction side faces. The recesses may be chemically etched, mechanically drilled, laser drilled, or the like.
FIG. 19 shows an RMC 340 otherwise similar to the RMC 84 but wherein the tapering portion 342 has arrays of protrusions 344 along the pressure and suction side faces. The protrusions may be formed by welding or cladding or may be left after an etching, mechanical machining, laser drilling, EDM, or the like.
FIG. 20 shows an RMC 350 otherwise similar to the RMC 84 but wherein the tapering portion 352 has a streamwise concavity extending 354 along the suction side face. The concavity may be formed in the initial machining.
FIG. 21 shows an RMC 360 otherwise similar to the RMC 84 but wherein the tapering portion 362 has a streamwise concavity extending 364 along the pressure side face. The concavity may be formed in the initial machining
FIG. 22 shows an RMC 370 otherwise similar to the RMC 84 but wherein the tapering portion 372 tapers along both the pressure and suction side faces. Also, the exemplary RMC 370 has a thin trailing portion 374 in place of the thick trailing portion 110 .
One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the principles may be implemented using modifications of various existing or yet-developed processes, apparatus, or resulting cast article structures (e.g., in a reengineering of a baseline cast article to modify cooling passageway configuration). In any such implementation, details of the baseline process, apparatus, or article may influence details of the particular implementation. Accordingly, other embodiments are within the scope of the following claims. | A method for manufacturing an investment casting core uses a metallic blank having a thickness between parallel first and second faces less than a width and length transverse thereto. The blank is locally thinned from at least one of the first and second faces. The blank is through-cut across the thickness. | 1 |
CROSS-REFERENCE TO RELATED DOCUMENTS
[0001] The present invention claims priority to a U.S. provisional patent application 61/693,929, filed Aug. 28, 2012 and entitled “Enhanced Watercraft”, disclosure of which is incorporated herein in its entirety at least by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention is in the technical area of primarily personal watercraft, and pertains more particularly to peripheral equipment and enhancements for paddleboards, kayaks, canoes, and surfboards.
[0004] 2. Description of Related Art
[0005] Paddleboards, and other watercraft of many different descriptions and manufacture, are known in the art. There are, in the present inventor's opinion, many shortcomings that might be provided to improve the utility of such watercraft. Enhancements and improvements according to embodiments of the present invention are provided and described in enabling detail below, and apply to all such watercraft.
BRIEF SUMMARY OF THE INVENTION
[0006] In an embodiment of the invention a paddleboard system is provided, comprising a paddleboard having an upper surface, a lower surface and a specific peripheral outer shape, and a fitted skirt having the specific peripheral outer shape of the paddleboard and additional material providing a first extension on the lower surface and a second extension on the upper surface fully around the specific peripheral outer shape, such that the fitted skirt is enabled to engage the paddleboard and stay in place in use.
[0007] In one embodiment material of the skirt is woven cloth, and the skirt additionally comprises a drawstring channel around an inner edge of the second extension with a drawstring and an opening at one point, enabling drawing the skirt tightly to the paddleboard. Also in one embodiment there are one or more elastic bands joined to the fitted skirt, providing tension to engage the skirt to the paddleboard.
[0008] In one embodiment the material of the skirt is a stretchable rubberlike material molded in the peripheral outer shape of the paddleboard, smaller then the shape of the paddleboard by an amount that the skirt is enabled to be stretched over the shape of the paddleboard. Also in one embodiment there is further a plurality of light-emitting diodes (LEDs) joined to fabric of the fitted skirt in a manner to be visible to observers, the LEDs wired together and the wiring having a connector to a power supply. In one embodiment there is a rechargeable battery incorporated into the fitted skirt, and in another a rechargeable battery integrated on or into the paddleboard.
[0009] In yet another embodiment of the invention the system comprises a control system coupled to the wiring of the LEDs and enabled to control one or more of lighting of individual LEDs, timing of on-off for individual and groups of LEDs, and color of LEDs. In some cases the control system is built into the upper surface of the paddleboard, including input mechanisms for a user to initiate functions of the control system, and in other embodiments there is an oar for use in propelling the paddleboard, and the control system is incorporated in the oar, including input mechanisms for a user to initiate functions of the control system.
[0010] In some embodiments with the stretchable rubberlike material there is also a plurality of light-emitting diodes (LEDs) joined to material of the fitted skirt in a manner to be visible to observers, the LEDs wired together and the wiring having a connector to a power supply. In these embodiments as well there may be rechargeable battery incorporated into the fitted skirt, or integrated on or into the paddleboard.
[0011] In embodiments with the stretchable rubberlike material there may be a control system coupled to the wiring of the LEDs and enabled to control one or more of lighting of individual LEDs, timing of on-off for individual and groups of LEDs, and color of LEDs. The control system may be built into the upper surface of the paddleboard, including input mechanisms for a user to initiate functions of the control system, or may be incorporated in an oar for use in propelling the paddleboard, wherein the control includes input mechanisms for a user to initiate functions of the control system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0012] FIG. 1 is a view of a person standing upright on a stand-up paddleboard in the prior art.
[0013] FIG. 2 is a view of a paddleboard having a fabric skirt according to an embodiment of the present invention.
[0014] FIG. 3 is a view of a portion of the board of FIG. 2 showing a drawstring in an embodiment of the invention.
[0015] FIG. 4 is a view of a paddleboard in one embodiment of the present invention to which lighting has been applied.
[0016] FIG. 5 shows a reel holding a long strip of LED waterproof lights.
[0017] FIG. 6 shows a remote controller in an embodiment of the invention.
[0018] FIG. 7 is a view of a paddleboard in an embodiment of the invention with a battery compartment and control switches built in.
[0019] FIG. 8 illustrates yet another embodiment of the invention wherein a paddleboard has a skirt that is molded in a flexible, rubberlike material such as neoprene.
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 1 is a view of a young man standing upright on a stand-up paddleboard 101 , holding a single paddle 102 . The paddleboard shown is typical of many, which are buoyant enough that an adult may stand upright and the board will remain floating and stable. Paddleboards are commercially available in differing size and buoyancy for children and adults, and a person may choose and purchase a paddleboard suitable to that person's size and weight as well as ability or discipline.
[0021] It may be seen in FIG. 1 , which is representative of the art at the time of filing the present application, that such boards typically are a bit upturned in the forward and, that is, the direction the board will be propelled, and typically have a marked area for the user to stand. That area may have a non-slip surface applied for convenience. It is clear in FIG. 1 as well that the paddle has a substantially elongated handle and a broad functional end, because the paddle is used while standing, and the length is convenient for a sure stroke. Paddleboards are used in following descriptions of embodiments of the present invention, and are an important area of application of principles and enhancements of the invention. It is to be understood, however, that many of the peripherals and enhancements described may be applied to personal watercraft of other sorts.
[0022] As paddleboarding has developed as a sport and a pastime, night use has become popular. The present invention pertains particularly to enhancements for night use with paddleboards, paddles and leashes, and to other watercraft and peripheral equipment, but night use is not a specific limitation.
[0023] The board seen in FIG. 1 may a decorative exterior with some color and symbols. One object of the present invention is to provide elements whereby the appearance of such a board may be easily changed, particularly at night. In following descriptions paddleboards are referenced as watercraft benefiting from enhancements and improvements according to embodiments of the invention, but paddleboard are just one sort of watercraft that may benefit. Many embodiments described are equally applicable to such as kayaks, canoes, and surfboards, as well as to other sorts of watercraft.
[0024] FIG. 2 is a view of a paddleboard 201 lying out of the water and upside down, showing a rear-mounted small keel or fin 203 , which is provided on many models of paddleboards to help stabilize the board in use and to prevent side-sliding when paddling and changing direction. Paddleboard 201 has in this embodiment an add-on fabric skirt 202 which in many embodiments has a vibrant color and design. The skirt is made to be of a size to fit this particular board, or many boards of this approximate size, and is assembled to the board around edges of the board. The skirt may be continuous, or may have an interface where the skirt may be joined when fitted to the board.
[0025] Skirt 202 is, in this embodiment, joined to the board by a drawstring 301 drawn taught and tied, as shown in FIG. 3 . The skirt has a sewn-in channel around the periphery for the drawstring. It will be apparent to the skilled person that the channel may have an opening elsewhere than at the head end of the board as shown in FIG. 3 , or may have a plurality of openings in different places in order to weave led light strips through. There also may be more than one drawstring. In alternative embodiments other means for tightening such a skirt may be use, such as elastic bands and the like.
[0026] Skirt 202 may be made of any one of a variety of materials, such as canvas fabrics, polyurethane, super flex sanaprene, plastic neoprene or any other suitable flexible material, and may have any one of many known protective materials applied to protect against salt water, physical damage, and harmful sun rays etc . . . Designs and colors may be applied in many different ways. Similarly the drawstring may be of any one of a variety of materials, such as plastics or fabric materials, and may in at least one embodiment be of a flexible material, such that the skirt may be quickly mounted, the flexibility of the string or skirt may hold the skirt in place, and there will be no need to tie or untie a drawstring if the skirt itself is of a flexible fabric, and a drawstring need not be used.
[0027] In another embodiment the fabric of the skirt may itself be a stretch fabric, and such a skirt may be quickly mounted or demounted by stretching the fabric to place the skirt in place or remove it from the paddleboard.
[0028] In another embodiment the skirt may itself be a translucent stretch polymer, plastic, sanaprene or any stretchable material that would also adhere to the board so that it stays in place by itself. Such a skirt may be quickly mounted or demounted by stretching the material to place the skirt in place or remove it from the paddleboard. Such a skirt (can be translucent) may also have lights molded in with the skirt so that the lights are protected from the water.
[0029] In another embodiment of the invention strips of phosphorescent material (commercially available) may be used instead of LED strips for at least some lighting elements on a watercraft. These strips gain energy during daylight hours from sunlight, and glow in the dark.
[0030] In yet another embodiment of the present invention lights may be added in a variety of different ways to a paddleboard to enhance the use of such a board in low-light conditions, or at night. FIG. 4 is a view of a paddleboard in one embodiment to which lighting has been applied. In this particular example a long string 403 of connected green LEDs 404 has been assembled to paddleboard 401 by providing a transparent skirt 402 with a channel, similar to a drawstring channel, into which LED string 403 is inserted or woven. The insertion may be done before or after the skirt is applied to the paddleboard and an on-board battery may be provided as a power supply for the LEDs, along with an on-off switch. The battery and switch are not shown in FIG. 4 , but may be provided in a number of different ways. For example, a rechargeable battery may be provided in the fabric of a skirt, with a tether to couple to a charging source as needed, either with the skirt in place on the paddleboard, or with the skirt removed. In other instances a battery may be provided in or on the board itself, such as in a well accessible from the top of the board.
[0031] The position of lighting elements on a paddleboard or other watercraft may be changed for different effects. For example, in some embodiments lighting elements may be positioned in various places and patterns on the top of the board, as well as in a skirt around the periphery of the board, or may be placed as well on the underside to produce perhaps a glow effect. There is no limitation as to the placement of lighting elements in the general sense.
[0032] FIG. 5 is a view of a reel 501 holding a long strip of LEDs, having an end connector 502 which is useful for connecting the strip to a battery pac or for connecting to another string of LEDs. Strips of this sort are commercially available, and may be capable of a single color, or many colors, which colors may be programmed to display in a pre-programmed order via a remote control. In other embodiments of the invention lighting elements may be provided in different ways.
[0033] FIG. 6 is a view of an exemplary controller for use with an LED strip like the strip shown on reel 501 in FIG. 5 , or for other lighting arrangements installed on a personal watercraft like a paddleboard. This controller has firmware and inputs whereby different programs of colors and timing may be displayed by the LEDs in the strip. Other inputs allow choice of colors and selectable color sequences, as well as changes in the timing for colors and flashing or fading. In other embodiments controllers may be provided that are programmable, and a user may develop different programs.
[0034] FIG. 7 is a plan view of a portion of a paddleboard 701 in an embodiment of the present invention, with a built-in battery compartment 702 and a user control interface comprising buttons 703 , 704 , 705 and 706 . In this embodiment board 701 has a compartment formed into the board, which is sized a shaped for a battery. The compartment, with the battery installed, is covered with a waterproof cover 702 . The battery may also be formed flat (not shown) with suction cups for adhesion to the board. The battery may be charged with solar during the day, or may be charged in any one of several conventional ways. There also may be a control board within the compartment with firmware and memory and other electronic components necessary for different control modes for lights. In some embodiments there are passages within board 701 from the battery compartment for wires, to connect to switches 703 through 706 and to LEDs and LED strips not shown.
[0035] Batteries and other forms of power may be supplied in many different ways, and the embodiments described herein are not limited by any specific mode of providing power. Batteries may be in compartments in a board or in another sort of watercraft, or may be attached and carried in any of several different ways.
[0036] Switch 703 is in this example is an off-on toggle switch that turns the light system off and on. Switch 704 , when the system is on, toggles between several preprogrammed sequences of colors and timing. Switches 705 and 706 may be used for different purposes. For example, in one embodiment switch 705 is a temporary disconnect switch that may be depressed by a user, by toe or heel, and the lights will be off while the switch is depressed, but come back on when the switch is released. This function may be used for signaling purposes by a user, because the user can control the timing of the off cycles. Users might employ pre-arranged signaling sequences, or even Morse code, for example. Switch 706 might be set up to provide a special color and rapid flashing to be recognized by other users as a distress signal. There are many possibilities.
[0037] In another embodiment transparent and semitransparent paddles are provided with LEDs inserted through passages drilled, molded or otherwise provided in the paddle shaft and/or the paddle end, along with a compartment for batteries and buttons on the handle end for a user to activate the LEDs and to initiate preprogrammed sequences of colors and timings. Solar may also be incorporated with the paddle to charge batteries contained within the paddle.
[0038] In yet another embodiment of the invention there is a power pack in or on the paddleboard along with circuitry for controlling LEDs associated with the board, either mounted in a skirt or embedded in the board itself or attached to the board, but control for the user is embodied in the paddle. In this embodiment a small power pack is provided in the handle and there is an interface with buttons and switches for the user to control all functions of the LEDs associated with the paddleboard. In one embodiment the paddle is tethered to the board by a communication cable, and inputs by the user are communicated to the board circuitry by this cable. This communications cable can also double as a lighted leash connecting the paddle to the board. In a preferred embodiment circuitry on the board and in the handle of the paddle is enabled for Bluetooth™ or any other wireless communication protocols that exist, and signals are communicated wirelessly. In some other embodiments there may also be a speaker and a microphone, and a user's paddle may connect to another user's paddle, such that users within wireless range may talk to one another. Control of another's lights may also be accomplished for a variety of purposes. In another embodiment one user controls the lights associated with a plurality of other users boards so that folks on shore may enjoy a choreographed light show of sorts. Control of a plurality of lighted boards may also be done from shore by a master controller. Emergency light communication may also be done via wireless technology alerting other users of a particular emergency or other communication.
[0039] In some embodiments a paddle may have glow-in-the-dark either in channels in the paddle or joined to the outside of the paddle. In other embodiments there may be a leash that is used to tether a person to the board or watercraft, and the leash may be enhanced with lighting elements.
[0040] FIG. 8 illustrates yet another embodiment of the invention wherein a paddleboard 801 has a skirt 802 that is molded in a flexible, rubberlike material such as neoprene. Skirt 802 is molded in the shape of a particular board for which the skirt is intended, but is molded at a somewhat smaller size than the exact outside shape of the paddleboard. The difference will be a small percentage, such as from 5% to 10%. The skirt may then be stretched over the paddleboard, and will be firmly positioned when installed. It may be seen in FIG. 8 that skirt 802 has a portion 803 that may lie flat on the top of the paddleboard. This flat portion may be shaped differently for different models of skirts for a particular paddleboard, to provide an extensive upper region, or a small upper region.
[0041] In some embodiments LEDs or other lighting elements 804 may be integrated with skirt 802 . An LED strip may be provided within the skirt with openings for the individual LEDs 804 to show through the skirt. With lighting elements, batteries may be provided as described above, either in the skirt, or in or on the board, and control elements as also described above may also be provided.
[0042] The skilled person will understand that there are many alterations that might be made to the embodiments described above without departing from the spirit and scope of the invention. | A paddleboard system includes a paddleboard having an upper surface, a lower surface and a specific peripheral outer shape, and a fitted skirt having the specific peripheral outer shape of the paddleboard and additional material providing a first extension on the lower surface and a second extension on the upper surface fully around the specific peripheral outer shape, such that the fitted skirt is enabled to engage the paddleboard and stay in place in use. | 1 |
This application is a divisional of U.S. Application Ser. No. 08/655,835, filled May 31, 1996, now U.S. Pat. No. 5,824,486, issued Oct. 20, 1998.
The present invention relates to the field of drug discovery, particularly with respect to drugs that have an effect on glycine-mediated neurotransmission in the nervous system.
Synaptic transmission is a complex form of intercellular communication that involves a considerable array of specialized structures in both the pre- and post-synaptic neuron. High-affinity neurotransmitter transporters are one such component, located on the pre-synaptic terminal and surrounding glial cells (Kanner and Schuldiner, CRC Critical Reviews in Biochemistry, 22, 1032 (1987)). Transporters sequester neurotransmitter from the synapse, thereby regulating the concentration of neurotransmitter in the synapse, as well as its duration therein, which together influence the magnitude of synaptic transmission. Further, by preventing the spread of transmitter to neighboring synapses, transporters maintain the fidelity of synaptic transmission. Last, by sequestering released transmitter into the presynaptic terminal, transporters allow for transmitter reutilization.
Neurotransmitter transport is dependent on extracellular sodium and the voltage difference across the membrane; under conditions of intense neuronal firing, as, for example, during a seizure, transporters can function in reverse, releasing neurotransmitter in a calcium-independent non-exocytotic manner (Attwell et al., Neuron, 11, 401-407 (1993)). Pharmacologic modulation of neurotransmitter transporters thus provides a means for modifying synaptic activity, which provides useful therapy for the treatment of neurological and psychiatric disturbances.
The amino acid glycine is a major neurotransmitter in the mammalian nervous system, functioning at both inhibitory and excitatory synapses. By nervous system, both the central and peripheral portions of the nervous system are intended. These distinct functions of glycine are mediated by two different types of receptor, each of which is associated with a different class of glycine transporter. The inhibitory actions of glycine are mediated by glycine receptors that are sensitive to the convulsant alkaloid, strychnine, and are thus referred to as "strychnine-sensitive." Such receptors contain an intrinsic chloride channel that is opened upon binding of glycine to the receptor; by increasing chloride conductance, the threshold for firing of an action potential is increased. Strychnine-sensitive glycine receptors are found predominantly in the spinal cord and brainstem, and pharmacological agents that enhance the activation of such receptors will thus increase inhibitory neurotransmission in these regions.
Glycine functions in excitatory transmission by modulating the actions of glutamate, the major excitatory neurotransmitter in the central nervous system. See Johnson and Ascher, Nature, 325, 529-531 (1987); Fletcher et al., Glycine Transmission, (Otterson and Storm-Mathisen, eds., 1990), pp. 193-219. Specifically, glycine is an obligatory co-agonist at the class of glutamate receptor termed N-methyl-D-aspartate (NMDA) receptor. Activation of NMDA receptors increases sodium and calcium conductance, which depolarizes the neuron, thereby increasing the likelihood that it will fire an action potential. NMDA receptors are widely distributed throughout the brain, with a particularly high density in the cerebral cortex and hippocampal formation.
Molecular cloning has revealed the existence in mammalian brains of two classes of glycine transporters, termed GlyT-1 and GlyT-2. GlyT-1 is found predominantly in the forebrain, and its distribution corresponds to that of glutamatergic pathways and NMDA receptors (Smith, et al., Neuron, 8, 927-935 (1992)). Molecular cloning has further revealed the existence of three variants of GlyT-1, termed GlyT-1a, GlyT-1b and GlyT-1c (Kim et al., Molecular Pharmacology, 45, 608-617 (1994)), each of which displays a unique distribution in the brain and peripheral tissues. These variants arise by differential splicing and exon usage, and differ in their N-terminal regions. GlyT-2, in contrast, is found predominantly in the brain stem and spinal cord, and its distribution corresponds closely to that of strychnine-sensitive glycine receptors (Liu et al., J. Biological Chemistry, 268, 22802-22808 (1993); Jursky and Nelson, J. Neurochemistry, 64, 1026-1033 (1995)). These data are consistent with the view that, by regulating the synaptic levels of glycine, GlyT-1 and GlyT-2 selectively influence the activity of NMDA receptors and strychnine-sensitive glycine receptors, respectively.
Sequence comparisons of GlyT-1 and GlyT-2 have revealed that these glycine transporters are members of a broader family of sodium-dependent neurotransmitter transporters, including, for example, transporters specific for γ-amino-n-butyric acid (GABA) and others. Uhl, Trends in Neuroscience, 15, 265-268 (1992); Clark and Amara, BioEssays, 15, 323-332 (1993). Overall, each of these transporters includes 12 putative transmembrane domains that predominantly contain hydrophobic amino acids. Comparing rat GlyT-1a or rat GlyT-1b to rat GlyT-2, using the Lipman-Pearson FASTA algorithm, reveals a 51% amino acid sequence identity and a 55% nucleic acid sequence identity. Comparison of the sequence of human GlyT-1a, human GlyT-1b, or human GIyT-1c with rat GlyT-2 reveals in each case a 51% amino acid sequence identity and a 53-55% nucleic acid sequence identity. However, there are segments of human GlyT-1c 16 amino acids in length whose amino acid sequences are 100% identical to those of rat GlyT-2; the corresponding nucleic acid sequence of this region, which is 48 nucleotides in length, is 78-85% identical between the two transporters. A yet longer stretch of 5 approximately 260 amino acids displays 53% amino acid sequence identity between human GIyT-1c and rat GlyT-2; the corresponding nucleotide sequence for this region, 780 nucleotides in length, displays about 66% sequence identity between the two transporters.
Compounds that inhibit or activate glycine transporters would be expected to alter receptor function, and provide therapeutic benefits in a variety of disease states. For example, inhibition of GlyT-2 can be used to diminish the activity of neurons having strychnine-sensitive glycine receptors via increasing synaptic levels of glycine, thus diminishing the transmission of pain-related (i.e., nociceptive) information in the spinal cord, which has been shown to be mediated by these receptors. Yaksh, Pain, 111-123 (1989). Additionally, enhancing inhibitory glycinergic transmission through strychnine-sensitive glycine receptors in the spinal cord can be used to decrease muscle hyperactivity, which is useful in treating diseases or conditions associated with increased muscle contraction, such as spasticity, myoclonus, and epilepsy (Truong et al., Movement Disorders, 3, 77-87(1988); Becker, FASEB J., 4, 2767-2774 (1990)). Spasticity that can be treated via modulation of glycine receptors is associated with epilepsy, stroke, head trauma, multiple sclerosis, spinal cord injury, dystonia, and other conditions of illness and injury of the nervous system.
NMDA receptors are critically involved in memory and learning (Rison and Stanton, Neurosci. Biobehav. Rev., 19, 533-552 (1995); Danysz et al., Behavioral Pharmacol., 6, 455-474 (1995)); and, furthermore, decreased function of NMDA-mediated neurotransmission appears to underlie, or contribute to, the symptoms of schizophrenia (Olney and Farber, Archives General Psychiatry, 52, 998-1007 (1996)). Thus, agents that inhibit GlyT-1 and thereby increase glycine activation of NMDA receptors can be used as novel antipsychotics and anti-dementia agents, and to treat other diseases in which cognitive processes are impaired, such as attention deficit disorders and organic brain syndromes. Conversely, over-activation of NMDA receptors has been implicated in a number of disease states, in particular the neuronal death associated with stroke and possibly neurodegenerative diseases, such as Alzheimer's disease, multi-infarct dementia, AIDS dementia, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis or other conditions in which neuronal cell death occurs, such as stroke and head trauma. Coyle & Puttfarcken, Science, 262, 689-695 (1993); Lipton and Rosenberg, New Engl. J. of Medicine, 330, 613-622 (1993); Choi, Neuron, 1, 623-634 (1988). Thus, pharmacological agents that increase the activity of GlyT-1 will result in decreased glycine-activation of NMDA receptors, which activity can be used to treat these, and related, disease states. Similarly, drugs that directly block the glycine site on the NMDA receptors can be used to treat these and related disease states.
Methods and materials are needed to identify the aforementioned pharmacological agents. In particular, a drug screening method or methods relating to the identification of pharmacological agents that regulate glycine transport or interact with glycine receptors are needed.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to materials and methods for the identification of agents that regulate glycine transport in or out of cells, or that interact with glycine receptors. Such materials include cells having transfected therein a glycine transporter. The methods relate to the manipulation of such cells such that agents are identified that inhibit or stimulate intake or outflow of glycine with respect to a given glycine transporter.
In a preferred embodiment, the present invention relates to a non-mammalian cell comprising an exogenous nucleic acid encoding a glycine transporter. Such an embodiment allows for the specific demonstration of the activity of a mammalian transporter in a genetically different background. A non-mammalian cell of the present invention is selected from the group consisting of avian, fungal, insect, and reptilian; most preferably the cell is avian. Preferably, the exogenous nucleic acid of the present invention is mammalian; more preferably the exogenous nucleic acid is human or rat. As noted, the inventive non-mammalian cell includes the glycine transporter, which is glycine transporter-1 (GlyT-1) or glycine transporter-2 (GlyT-2), wherein GlyT-1 is GlyT-1a, GlyT-1b, or GlyT-1c. Preferably, the glycine transporter is GlyT-1, wherein the exogenous nucleic acid is selected from the group consisting of SEQ ID NO:1, SEQ ID NO:2, and SEQ ID NO:3. In another embodiment, the glycine transporter is GlyT-2, wherein the exogenous nucleic acid is SEQ ID NO:4. The non-mammalian cell of the present invention preferably is a quail fibroblast, and most preferably is a QT-6 cell.
Another preferred embodiment of the present invention relates to a method for the analysis or screening of an agent for treatment of pain, muscle hyperactivity, neuronal cell death, schizophrenia, memory or cognitive disorders, or other disorders or conditions associated with a nervous system disorder or condition, comprising culturing separately first and second non-mammalian cells, wherein the first and second non-mammalian cells are of the same strain and comprise an exogenous nucleic acid encoding a glycine transporter, contacting the first non-mammalian cell with the agent, and screening for the enhancement or inhibition of glycine transport into the first non-mammalian cell as compared to glycine transport into the second non-mammalian cell that was not contacted with the compound. The nervous system disorder or condition noted hereinabove is selected from the group consisting of spasticity, muscle spasm, myoclonus, epilepsy, stroke, head trauma, multiple sclerosis, spinal cord injury, dystonia, Alzheimer's disease, multi-infarct dementia, AIDS dementia, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Preferably, the glycine transporter used in the context of this method is GlyT-1 or GlyT-2, wherein GlyT-1 is GlyT-1a, GlyT-1b, or GlyT-1c. A further preferred embodiment of the present invention includes first and second non-mammalian cells comprising exogenous nucleic acid that encodes GlyT-1, such as exogenous nucleic acid that comprises SEQ ID NO:1, SEQ ID NO:2, or SEQ ID NO:3. Alternatively, the first and second non-mammalian cells of the present invention includes exogenous nucleic acid that encodes GlyT-2, such as exogenous nucleic acid that comprises SEQ ID NO:4. In a preferred embodiment, the non-mammalian cell of the present invention is a QT-6 cell. In yet a further preferred embodiment, the drug discovered by the inventive method is an enhancer or inhibitor of GlyT-1 or GlyT-2 or both GlyT-1 and GlyT-2.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are graphs that depict the results of heterologous expression of glycine transporters in QT-6 cells.
FIGS. 2A and 2B are graphs that respectively depict the attenuation of MK-801 binding by a glycine site antagonist (FIG. 2A) and the potentiation of MK-801 binding by a glycine site agonist (FIG. 2B).
FIG. 3 is a bar graph that depicts NMDA receptor-mediated calcium uptake in primary neuronal cell cultures, and its blockade by the glycine site antagonist L-689,560.
DETAILED DESCRIPTION
The present invention is directed to materials and methods for the identification of agents that regulate glycine transport in or out of cells or that interact with glycine receptors. In particular, such glycine transport is mediated or caused by action of the glycine transporter type 1 (GlyT-1) or glycine transporter type 2 (GlyT-2). GlyT-1 has been found to express as three different isoforms that differ in their 5' ends; namely, GlyT-1a [SEQ ID NO:1], GlyT-1b [SEQ ID NO:2], and GlyT-1c [SEQ ID NO:3]. GlyT-1a is transcribed from a different promoter than is GlyT-1b and GlyT-1c; all three isoforms differ by differential splicing and exon usage. Adams et al., J. Neurosci., 15, 2524-2532 (1995); Kim et al., Molec. Pharmacol., 45, 608-617 (1994).
The glycine transporter genes and their respective gene products are responsible for the reuptake of glycine from the synaptic cleft into presynaptic nerve endings or glial cells, thus terminating the action of glycine. Neurological disorders or conditions associated with improperly controlled glycine receptor activity, or which could be treated with therapeutic agents that modulate glycine receptor activity, include spasticity (Becker, FASEB Journal, 4, 2767-2774 (1990)) and pain realization (Yaksh, Pain, 37, 111-123 (1989)). Additionally, glycine interacts at N-methyl-D-aspartate (NMDA) receptors, which have been implicated in learning and memory disorders and certain clinical conditions such as epilepsy, Alzheimer's and other cognition-related diseases, and schizophrenia. See Rison and Stanton, Neurosci. Biobehav. Rev., 19, 533-552 (1995); Danysz et al., Behavioral Pharmacol., 6, 455-474 (1995).
Compounds that inhibit GlyT-1 mediated glycine transport will increase glycine concentrations at NMDA receptors, which receptors are located in the forebrain, among other locations. This concentration increase elevates the activity of NMDA receptors, thereby alleviating schizophrenia and enhancing cognitive function. Alternatively, compounds that interact directly with the glycine receptor component of the NMDA receptor can have the same or similar effects as increasing or decreasing the availability of extracellular glycine caused by inhibiting or enhancing GlyT-1 activity, respectively. See, for example, Pitkanen et al., Eur. J. Pharmacol., 253, 125-129 (1994); Thiels et al., Neuroscience, 46, 501-509 (1992); and Kretschmer and Schmidt, J. Neurosci., 16, 1561-1569 (1996). Compounds that inhibit GlyT-2 mediated glycine transport will increase glycine concentrations at receptors located primarily in the brain stem and spinal cord, where glycine acts as an inhibitor of synaptic transmission. These compounds are effective against epilepsy, pain and spasticity, and other such conditions. See, for example, Becker, supra, and Yaksh, supra.
Accordingly, the identification of agents that enhance or inhibit the glycine transporter, or inhibit or activate the glycine receptor portion of the NMDA receptor, is important for the development of drugs useful in the treatment of such neurological conditions and disorders. The present invention provides materials and methods that are suitable for such screening. In particular, GlyT-1a, -1b, -1c, and GlyT-2 DNA sequences, when placed into a suitable expression vector and a suitable host is transformed therewith, the GlyT-1a, -1b, -1c, and GlyT-2, respectively, glycine transporter polypeptides are synthesized and form the respective glycine transporter. Such transformed cells may form stable lines that constitutively or inductively express the GlyT DNA, thus expressing glycine transporters. Alternatively, other such cells may exhibit transient expression of the GlyT DNA and protein. Either of such transfected cells, together or separately, are useful for screening assays to determine whether a candidate agent has characteristics of enhancing or inhibiting glycine transport, as disclosed herein with respect to the present invention. Additionally, suitable primary neuronal cell cultures that have NMDA receptors and glycine transporters are also used in the context of the present invention to test compounds for the ability to activate or inhibit either the glycine transporter, the glycine receptor portion of the NMDA receptor, or both. Such tests also have the form of binding assays using membranes from any suitable source that includes NMDA receptors, such as brain tissue.
Suitable expression vectors include pRc/CMV (Invitrogen), pRc/RSV (Invitrogen), pcDNA3 (Invitrogen), Zap Express Vector (Stratagene Cloning Systems, LaJolla, Calif.; hereinafter "Stratagene"), pBk/CMV or pBk-RSV vectors (Stratagene), Bluescript II SK +/- Phagemid Vectors (Stratagene), LacSwitch (Stratagene), pMAM and pMAM neo (Clontech), among others. A suitable expression vector is capable of fostering expression of the included GlyT DNA in a suitable host cell, preferably a non-mammalian host cell, which can be eukaryotic, fungal, or prokaryotic. Such preferred host cells include, but are not limited to, avian, fungal, insect, and reptilian cells. Preferred host cells are avian, fungal, and insect cells. Most preferred host cells are avian cells. Preferred avian cells include those of quails, chickens, and turkeys; more preferred, of quails. Most preferred of such cells are quail fibroblast, such as, in particular, QT-6.
The GlyT DNA that is inserted into one of the aforementioned expression vectors is any suitable DNA that encodes a glycine transporter. Preferably, the GlyT DNA is obtained from a suitable animal, including but not limited to birds and mammals, for example. Preferred mammals include humans, mice, rats, cows, pigs, among others; more preferably, the GlyT DNA is obtained from a human or a rat; most preferably, the GlyT DNA is obtained from a human. In one embodiment, the GlyT DNA is preferably comprised of SEQ ID NO:1, SEQ ID NO:2, or SEQ ID NO:3, with respect to GlyT-1, and SEQ ID NO:4, with respect to GlyT-2. Any other suitable DNA that encodes glycine transporter type 1 activity is an equivalent substitution for SEQ ID Nos:1-3. Similarly, any other suitable DNA that encodes glycine transporter type 2 activity is an equivalent substitution for SEQ ID NO:4.
In another embodiment, the GlyT DNA used in the context of the present invention encodes a protein that has at least about 45% amino acid sequence identity with at least one of the proteins encoded by SEQ ID NOs:1-4, more preferably at least about 60% amino acid sequence identity, still more preferably at least about 75% amino acid sequence identity, yet still more preferably at least about 85% amino acid sequence identity. Sequence identity measurements as contemplated herein score conservative amino acid substitutions as identical, wherein conservative substitutions are those that cause exchanges of amino acids in the encoded protein, which amino acids have highly similar physicochemical characteristics or have been known empirically to substitute in homologous proteins. At the nucleic acid level, exchanges of nucleotides can occur that are neutral in their effect on the encoded protein sequence, in consequence of the redundancy of the genetic code, which could account for greater sequence variation at the nucleic acid level than at the amino acid level.
Such exchangeable amino acids are categorized within one of the following groups, wherein the amino acids are recited by their respective three-letter codes that are well known in the art:
1. Small aliphatic, nonpolar or slightly polar residues: Ala, Ser, Thr, Pro and Gly;
2. Polar, negatively charged residues and their amides: Asp, Asn, Glu and Gln;
3. Polar, positively charged residues: His, Arg and Lys;
4. Large aliphatic, nonpolar residues: Met, Leu, IIe, Val and Cys; and
5. Aromatic residues: Phe, Tyr and Trp.
A preferred listing of conservative substitutions, based on empirical evidence from studies on homologous protein sequences, is the following:
______________________________________Original Residue Substitution______________________________________Ala Gly, Ser Arg Lys Asn Gln, His Asp Glu Cys Ser Gln Asn Glu Asp Gly Ala, Pro His Asn, Gln Ile Leu, Val Leu Ile, Val Lys Arg, Gln, Glu Met Leu, Tyr, Ile Phe Met, Leu, Tyr Ser Thr Thr Ser Trp Tyr Tyr Trp, Phe Val Ile, Leu______________________________________
The types of substitutions selected is preferably, but not necessarily, based on the analysis of the frequencies of amino acid substitutions between homologous proteins of different species, such as that developed by Schulz et al., Principles of Protein Structure, Springer-Verlag, 1978, on the analyses of structure-forming potentials developed by Chou and Fasman, Biochemistry, 13, 211 (1974) and Adv. Enzymol., 47, 45-149 (1978), and on the analysis of hydrophobicity patterns in proteins developed by Eisenberg et al., Proc. Natl. Acad. Sci. USA, 81, 140-144 (1984); Kyte & Doolittle, J. Molec. Biol., 157, 105-132 (1981), and Goldman et al., Ann. Rev. Biophys. Chem., 15, 321-353 (1986).
GlyT DNAs that encode proteins that exhibit overall less than about 45% sequence identity with each of the proteins encoded by SEQ ID NOs:1-4 are nonetheless included as GlyT DNA to the extent that the related nucleic acid includes nucleotide and amino acid sequences specific to the genes that encode GlyT-1 or GlyT-2 or substantial portions thereof. By "substantial portions" it is intended that the included portion includes a continuous segment of at least about 50 nucleotides that encode a peptide sequence that exhibits at least about 80% amino acid sequence identity with the corresponding segment of the protein encoded by SEQ ID NOs:1, 2, 3, or 4; more preferredly, the substantial portion includes a continuous segment of at least about 500 nucleotides that encode a peptide sequence that exhibits at least about 70% amino acid sequence identity with the corresponding segment of the protein encoded by SEQ ID NOs:1, 2, 3, or 4; and yet more preferredly, the substantial portion includes a continuous segment of at least about 1000 nucleotides that encode a peptide sequence that exhibits at least about 60% amino acid sequence identity with the corresponding segment of the protein encoded by SEQ ID NOs:1, 2, 3, or 4.
As used in the context of the present invention, the specified sequence identity of a nucleic acid with respect to one of SEQ ID NOs:1-4, or substantial portions thereof, in part defines one embodiment of the GlyT DNA used to generate inventive gene constructs, vectors, and transformed hosts that can be used in the drug discovery method disclosed herein. Accordingly, the nucleic acid used in the context of the present invention is sequenced or otherwise suitably analyzed so as to compare its sequence to one of those of SEQ ID NO: 1, 2, 3, or 4.
Numerous methods for determining percent sequence identity are known in the art. One preferred method is to use version 6.0 of the GAP computer program for making sequence comparisons. The program is available from the University of Wisconsin Genetics Computer Group and utilizes the alignment method of Needleman and Wunsch, J. Mol. Biol., 48, 443, 1970 as revised by Smith and Waterman, Adv. Appl. Math., 2, 482, 1981. Another available method uses the FASTA computer program (Pearson and Lipman, Proc. Natl. Acad. Sci. USA, 85, 2444-2448 (1988)).
As noted above, the present invention relates to cells transfected with GlyT DNA, which is any suitable DNA that encodes a glycine transporter such that glycine transporter properties are expressed by the transfected cells. In one embodiment, such GlyT DNA is homologous to at least one of SEQ ID NOs:1-4, or a sequence complementary thereto; a preferred GlyT DNA of this embodiment encodes a protein that has at least about 45% sequence identity with respect to at least one of SEQ ID NOs:1-4. A more preferred GlyT DNA used in the context of the present invention comprises a nucleic acid selected from the group consisting of SEQ ID NOs:1-4, a nucleic acid complementary thereto, and a substantially equivalent nucleic acid. Such related GlyT DNAs as defined hereinabove are isolated using one of the SEQ ID NOs: 1-4, or substantial portions thereof, as a probe in any of a variety of conventional procedures of molecular biology, including but not limited to hybridization, PCR, or others, on genomic DNA or cDNA derived from organisms that have glycine transport activity, or on genomic or cDNA libraries derived from such organisms.
A "substantially equivalent" nucleic acid is a nucleic acid having a sequence that varies from one of SEQ ID NOs:1-4 by one or more substitutions, deletions, or additions, the effect of which does not result in an undesirable functional dissimilarity between the two nucleic acids. In other words, the polypeptide that results from the substantially equivalent sequence has the activity characteristic of the GlyT gene product. A difference in sequence at the amino acid level is understood to include amino acid differences, which range from a single amino acid substitution, deletion, or insertion to a number of amino acid substitutions, deletions, and/or insertions, wherein the resulting polypeptide is still recognizable as related to the GlyT protein in that functionality of the glycine transporter is preserved.
A method for the analysis or screening of an agent for treatment of a disease or condition associated with a nervous system disorder or condition comprises culturing separately first and second non-mammalian cells, wherein the first and second non-mammalian cells are preferably of the same species, more preferably of the same strain thereof, and comprise an exogenous nucleic acid encoding a glycine transporter as described herein, preferably either GlyT-1 or GlyT-2, wherein GlyT-1 is GlyT-1a, GlyT-1b, or GlyT-1c. The nervous system disorders or conditions for which the agent can be used for treatment include, but are not limited to, spasticity, myoclonas, muscle spasm, pain, muscle hyperactivity, epilepsy, stroke, head trauma, neuronal cell death, cognitive or memory disorders, multiple sclerosis, spinal cord injury, dystonia, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, attention deficit disorders, organic brain syndromes, and schizophrenia. In this method, the first non-mammalian cell is contacted with the agent, which is preferably a compound, such as a peptide or an organic compound, or a composition or mixture comprising same, as further discussed below, in the presence of a suitably-labeled glycine. Such a labeled glycine has incorporated into it, for example, a radioisotope, such as 3 H or 14 C. The contacted first non-mammalian cell is then tested for enhancement or inhibition of glycine transport into the first non-mammalian cell as compared to glycine transport into the second non-mammalian cell that was not contacted with the compound (i.e., the control cell). Such analysis or screening preferably includes activities of finding, learning, discovering, determining, identifying, or ascertaining.
An agent is an enhancer of glycine transport uptake if at the end of the aforestated test the amount of intracellular labeled glycine is greater in the agent-contacted non-mammalian cell than in the non-agent-contacted non-mammalian cell; conversely, an agent is an inhibitor of glycine transport if the amount of intracellular labeled glycine is greater in the non-agent-contacted non-mammalian cell as compared to the other. Preferably, the difference in glycine uptake between the tested first cell and the control second cell is at least about a factor of two; more preferably, the difference is at least about a factor of five; most preferably, the difference is at least about an order of magnitude or greater.
Agents identified using the inventive method are specific for GlyT-1a, GlyT-1b, GlyT-1c, GlyT-2, or any combination thereof. The same compound preferably is an inhibitor or an enhancer with respect to any one glycine transporter, but may have a neutral or opposite effect with another glycine transporter. Preferred agents have specificity to enhance or inhibit one glycine transporter and have neutral or negligible effect on other glycine transporters as compared to the effect on the indicated glycine transporter. Preferably, an agent having specificity for one glycine transporter with respect to a second glycine transporter has at least an order of magnitude greater potency for inhibiting or activating glycine uptake mediated by the first glycine transporter as compared to its effect on the second glycine transporter, as tested in transfected cells of the present invention. More preferred agents have differences in potency of at least two orders of magnitude for one glycine transporter as compared to the other.
An agent can be any suitable compound, material, composition, mixture, or chemical, including but not limited to polypeptides of two up to about 25 amino acids in length, preferably from two to about ten, more preferably from two to about five amino acids in length. Other suitable agents in the context of the present invention include small organic compounds, of molecular weight between about 100 daltons and about 5,000 daltons, and are composed of alkyls, aryls, alkenes, alkynes, and other suitable groups, including heteroatoms or not. Such organic compounds can be carbohydrates, including simple sugars, amino or imino acids, nucleic acids, steroids, and others. The chemicals tested as agents hereby may be prepared using combinatorial chemical processes known in the art or conventional means for chemical synthesis. Preferably, suitable agents are useful as drugs for treatment of the aforementioned or other nervous system disorders or conditions.
Agents identified that enhance or inhibit the glycine transporter, or inhibit or activate the glycine receptor portion of the NMDA receptor, using the methods described herein, include those wherein the agent is of the formula: ##STR1## or a pharmaceutically acceptable salt thereof, wherein: (1) X is nitrogen or carbon;
(2) Ar 1 is aryl, heteroaryl, arylalkyl wherein the alkyl is C1 to C2, or heteroarylalkyl wherein the alkyl is C1 to C2, and Ar 2 is aryl, heteroaryl, aryloxy, heteroaryloxy, arylalkyl wherein the alkyl is C1 to C2, heteroarylalkyl wherein the alkyl is C1 to C2, arylmethoxy, heteroarylmethoxy, arylthio, heteroarylthio, arylmethylthio, heteroarylmethylthio, or either Ar--N(R 6 )-- or Ar--CH 2 --N(R 6* )--, wherein R 6 and R 6* are hydrogen or (C1-C6) alkyl and Ar is aryl or heteroaryl,
(a) wherein when X is nitrogen Ar 2 is not aryloxy, heteroaryloxy, arylmethoxy, heteroarylmethoxy, arylthio, heteroarylthio, arylmethylthio, heteroarylmethylthio, Ar--N(R 6 )-- or Ar--CH 2 --N(R 6* --,
(b) wherein the aryl of Ar 1 or Ar 2 is phenyl or naphthyl,
(c) wherein the heteroaryl of Ar 1 or Ar 2 comprises a five-membered ring, a six-membered ring, a six-membered ring fused to a five-membered ring, or a six-membered ring fused to a six-membered ring, wherein the heteroaryl is aromatic and contains heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, with the remaining ring atoms being carbon,
(d) wherein the aryl or heteroaryl of Ar 1 and Ar 2 together can be substituted with up to six substituents selected from the group consisting of fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, amidosulfonyl which can have up to two (C1-C6) N-alkyl substitutions, (C1-C6) alkyl, (C2-C6) alkenyl, amino, (C1-C6) alkylamino, dialkylamino wherein each alkyl is independently C1 to C6, (C1-C6) alkoxy, (C2-C7) alkanoyl, (C2-C7) alkanoyloxy, trifluoromethoxy, hydroxycarbonyl, (C2-C7) alkyloxycarbonyl, aminocarbonyl that can be substituted for hydrogen with up to two (C1-C6) alkyl, (C1-C6) alkylsulfonyl, amidino that can independently substituted with up to three (C1-C6) alkyl, or methylenedioxy or ethylenedioxy with the two oxygens bonded to adjacent positions on the aryl or heteroarly ring structure, which methylenedioxy or ethylenedioxy can be substituted with up to two (C1-C6) alkyl,
(i.) wherein such substitutions to the aryl or heteroaryl of Ar 1 and Ar 2 can be combined to form a second bridge between Ar 1 and Ar 2 comprising (1) (C1-C2) alkyl or alkenyl, which can be independently substituted with one or more (C1-C6) alkyl, (2) sulfur, (3) oxygen, (4) amino, which can be substituted for hydrogen with one (C1-C6) alkyl, (5) carbonyl, (6) --CH 2 C(═O)--, which can be substituted for hydrogen with up to two (C1-C6) alkyl, (7) --C(═O)--O--, (8) --CH 2 --O--, which can be substituted for hydrogen with up to two (C1-C6) alkyl, (9) --C(═O)--N(R 24 )--, wherein R 24 is hydrogen or (C1-C6) alkyl, (10) --CH 2 --NH--, which can be substituted for hydrogen with up to three (C1-C6) alkyl, (11) --CH═N--, which can be substituted for hydrogen with (C1--C6) alkyl, or wherein the aryls or heteroaryls of Ar 1 and Ar 2 can be directly linked by a single bond;
(3) R 25 comprises (a) a straight-chained (C1-C4) aliphatic group,
(b) ═N--O--(R 26 ) when X is carbon, wherein R 26 is ethylene or propylene and the unmatched double bond is linked to X, or (c) --O--R 8 or --S--R 8* when X is carbon and Ar 2 is neither Ar--N(R 6 )--nor Ar--CH 2 --N(R 6* )--, wherein R 8 or R 8* is a (C2-C3) alkylene or (C2-C3) alkenylene and O or S is bonded to X,
(i.) wherein R 25 can be substituted with up to one hydroxy, up to one (C1-C6) alkoxy or up to one (C2-C7) alkanoyloxy, with up to two (C1-C6) alkyl, with up to one oxo, up to one (C1-C6) alkylidene, with the proviso that the hydroxy, alkoxy, alkanoyloxy or oxo substituents are not bonded to a carbon that is bonded to a nitrogen or oxygen,
(ii.) wherein the alkyl or alkylidene substituents of R 25 can be linked to form a 3 to 7-membered ring,
(iii.) wherein if X is nitrogen, X is linked to R 25 by a single bond and the terminal carbon of R 25 that links R 25 to N is saturated;
(4) R 2 (a) is not present when X is nitrogen, (b) is hydrogen, (C1-C6) alkyl, (C1-C6) alkoxy, cyano, (C2-C7) alkanoyl, aminocarbonyl, (C1-C6) alkylaminocarbonyl, dialkylaminocarbonyl wherein each alkyl is independently C1-C6, or Ar 9 where Ar 9 is independently as defined for Ar 1 , (c) comprises, where R 25 is not --O--R 8 , hydroxy, fluoro, chloro, bromo or (C2-C7) alkanoyloxy, (d) forms a double bond with an adjacent carbon or nitrogen from R 25 ;
(5) R 3 (a) is hydrogen, (C1-C6) alkyl, or phenyl or phenylalkyl wherein the alkyl is C1-C6 and either such phenyl can be substituted with up to 3 of the same substituents defined above for the aryl or heteroaryl of Ar 1 or Ar 2 , (b) is --CH(R 9 )--R 10 , wherein R 9 is the same as R 4 and R 10 is the same as R 5 , or (c) Z(Ar 3 )(Ar 4 )(R 11 )--R 12 , wherein R 12 is bonded to N, Z is independently the same as X, Ar 3 is independently the same as Ar 1 , Ar 4 is independently the same as Ar 2 , R 11 is independently the same as R 2 and R 12 is independently the same as R 25 ;
(6) R 4 and R 4* are independently hydrogen or (C1-C6) alkyl that can be bonded to complete a 3 to 7-membered ring, or one of R 4 and R 4* can be (C1-C6) hydroxyalkyl; and
(7) R 5 is (CO)NR 13 R 14 , (CO)OR 15 , (CO)SR 16 , (SO 2 )NR 17 R 18 , (PO)(OR 19 )(OR 20 ) or CN, wherein R 13 , R 14 , R 15 , R 16 R 17 , R 18 R 19 and R 20 are independently hydrogen, (C1-C8) alkyl which can incorporate a (C3-C8) cycloalkyl, wherein the carbon linked to the oxygen of R 15 or the sulfur of R 16 has no more than secondary branching and , (C2-C6) hydroxyalkyl, aminoalkyl where the alkyl is C2-C6 and the amino can be substituted with up to two (C1-C6) alkyls, arylalkyl wherein the alkyl is C1 to C6, heteroarylalkyl wherein the alkyl is C1 to C6, aryl or heteroaryl,
(a) wherein the aryl is phenyl or napthyl and the heteroaryl is a five-membered ring, a six-membered ring, a six-membered ring fused to a five-membered ring, or a six-membered ring fused to a six-membered ring, wherein the heteroaryl is aromatic and contains heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, with the remaining ring atoms being carbon,
(b) wherein the aryl, heteroaryl, aryl or arylalkyl or the heteroaryl of heteroarylalkyl can be substituted with up to three substituents selected from the group consisting of fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, amidosulfonyl which can have up to two (C1-C6) N-alkyl substitutions, (C1-C6) alkyl, (C2-C6) alkenyl, (C1-C6) alkylamine, dialkylamine wherein each alkyl is independently C1 to C6, amino, (C1-C6) alkoxy, (C2-C7) alkanoyl, (C2-C7) alkanoyloxy, trifluoromethoxy, hydroxycarbonyl, (C2-C7) alkyloxycarbonyl, aminocarbonyl that can be N-substituted with up to two (C1-C6) alkyl, (C1-C6) alkylsulfonyl, amidino that can substituted with up to 3 (C1-C6) alkyl, or methylenedioxy or ethylenedioxy with the two oxygens bonded to adjacent positions on the aryl or heteroaryl ring structure, which methylenedioxy or ethylenedioxy can be substituted with up to two (C1-C6) alkyl, and
(c) wherein R 13 and R 14 together with the nitrogen can form a 5 to 7-membered ring that can contain one additional heteroatom selected from oxygen and sulfur. Other suitable agents identified as above include those
wherein the agent is of the formula: ##STR2## or a pharmaceutically acceptable salt thereof, wherein: (1) X is nitrogen or carbon;
(2) Ar 1 is aryl, heteroaryl, arylalkyl wherein the alkyl is C1 to C2, or heteroarylalkyl wherein the alkyl is C1 to C2, and Ar 2 is aryl, heteroaryl, aryloxy, heteroaryloxy, arylalkyl wherein the alkyl is C1 to C2, heteroarylalkyl wherein the alkyl is C1 to C2, arylmethoxy, heteroarylmethoxy, arylthio, heteroarylthio, arylmethylthio, heteroarylmethylthio, or either Ar--N(R 6 )--or Ar--CH 2 --N(R 6* )--, wherein R 6 and R 6* are hydrogen or (C1-C6) alkyl and Ar can be aryl or heteroaryl,
(a) wherein when X is nitrogen Ar 2 is not aryloxy, heteroaryloxy, arylmethoxy, heteroarylmethoxy, arylthio, heteroarylthio, arylmethylthio, heteroarylmethylthio, Ar--N(R 6 )-- or Ar--CH 2 --N(R 6* )--,
(b) wherein the aryl of Ar 1 or Ar 2 is phenyl or naphthyl,
(c) wherein the heteroaryl of Ar 1 or Ar 2 comprises a five-membered ring, a six-membered ring, a six-membered ring fused to a five-membered ring, or a six-membered ring fused to a six-membered ring, wherein the heteroaryl is aromatic and contains heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, with the remaining ring atoms being carbon,
(d) wherein the aryl or heteroaryl of Ar 1 and Ar 2 together can be substituted with up to six substituents selected from the group consisting of fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, amidosulfonyl which can have up to two (C1-C6) N-alkyl substitutions, (C1-C6) alkyl, (C2-C6) alkenyl, amino, (C1-C6) alkylamino, dialkylamino wherein each alkyl is independently C1 to C6, (C1-C6) alkoxy, (C2-C7) alkanoyl, (C2-C7) alkanoyloxy, trifluoromethoxy, hydroxycarbonyl, (C2-C7) alkyloxycarbonyl, aminocarbonyl that can be substituted for hydrogen with up to two (C1-C6) alkyl, (C1-C6) alkylsulfonyl, amidino that can independently substituted for hydrogen with up to three (C1-C6) alkyl, or methylenedioxy or ethylenedioxy with the two oxygens bonded to adjacent positions on the aryl or heteroaryl ring structure, which methylenedioxy or ethylenedioxy can be substituted with up to two (C1-C6) alkyl,
(i.) wherein such substitutions to the aryl or heteroaryl of Ar 1 and Ar 2 can be combined to form a second bridge between Ar 1 and Ar 2 comprising (1) (C1-C2) alkyl or alkenyl, which can be independently substituted with one or more (C1-C6) alkyl, (2) sulfur, (3) oxygen, (4) amino, which can be substituted for hydrogen with one (C1-C6) alkyl, (5) carbonyl, (6) --CH 2 C(═O)--, which can be substituted for hydrogen with up to two (C1-C6) alkyl, (7) --C(═O)--O--, (8) --CH 2 --O--, which can be substituted for hydrogen with up to two (C1--C6) alkyl, (9) --C(═O)--N(R 24 )--, wherein R 24 is hydrogen or (C1-C6) alkyl, (10) --CH 2 --NH--, which can be substituted for hydrogen with up to three (C1--C6) alkyl, or (11) --CH═N--, which can be substituted for hydrogen with (C1-C6) alkyl, or wherein the aryls or heteroaryls of Ar 1 and Ar 2 can be directly linked by a single bond;
(3) R 1 comprises (a) a straight-chained (C2-C4) aliphatic group, (b) ═N--O--(CH 2 CH 2 )-- when X is carbon, wherein the unmatched double bond is linked to X, or (c) --O--R 8 or R 8* --when X is carbon and Ar 2 is neither Ar--N(R 6 )-- nor Ar--CH 2 --N(R 6* )--, wherein R 8 or R 8* is a (C2-C3) alkylene or (C2-C3) alkenylene and O or S is bonded to X,
(i.) wherein R 1 can be substituted with up to one hydroxy, up to one (C1-C6) alkoxy or up to one (C2-C7) alkanoyloxy, with up to two (C1-C6) alkyl, with up to one oxo, up to one (C1-C6) alkylidene, with the proviso that the hydroxy, alkoxy, alkanoyloxy or oxo substituents are not bonded to a carbon that is bonded to a nitrogen or oxygen,
(ii.) wherein the alkyl or alkylidene substituents of R 1 can be linked to form a 3 to 7-membered ring,
(iii.) wherein if X is nitrogen, X is linked to R 1 by a single bond and wherein the terminal carbon of R 1 that links R 1 to N is saturated;
(4) R 2 (a) is not present when X is nitrogen, (b) is hydrogen, (C1-C6) alkyl, (C1-C6) alkoxy, cyano, (C2-C7) alkanoyl, aminocarbonyl, (C1-C6) alkylaminocarbonyl or dialkylaminocarbonyl wherein each alkyl is independently C1 to C6, (c) comprises, where R 1 is not --O--R 8 or --S--R 8* --, hydroxy, fluoro, chloro, bromo or (C2-C7) alkanoyloxy, (d) forms a double bond with an adjacent carbon or nitrogen from R1;
(5) wherein Q together with the illustrated tertiary nitrogen and tertiary carbon bearing R 5 form ring C, wherein ring C is a 3 to 8-membered ring, a 3 to 8-membered ring substituted with a 3 to 6-membered spiro ring, or a 3 to 8-membered ring fused with a 5 to 6-membered ring, wherein the fused ring lacking the illustrated tertiary nitrogen can be aromatic or heteroaromatic, wherein for each component ring of ring C there are up to two heteroatoms selected from oxygen, sulfur or nitrogen, including the illustrated nitrogen, and the rest carbon, with the proviso that the ring atoms include no quaternary nitrogens, with the proviso that, in saturated rings, ring nitrogen atoms are separated from other ring heteroatoms by at least two intervening carbon atoms,
(a) wherein the carbon and nitrogen ring atoms of ring C can be substituted with up to three substituents selected from (C1-C6) alkyl, (C2-C6) alkenylene, cyano, nitro, trifluoromethyl, (C2-C7) alkyloxycarbonyl, (C1-C6) alkylidene, hydroxyl, (C1-C6) alkoxy, oxo, hydroxycarbonyl, aryl wherein the aryl is as defined for Ar 1 or heteroaryl wherein the heteroaryl is as defined for Ar 1 , with the proviso that ring atoms substituted with alkylidene, hydroxycarbonyl or oxo are carbon, with the further proviso that ring atoms substituted with hydroxyl or alkoxy are separated from other ring heteroatoms by at least two intervening carbon atoms,
(b) and wherein Q is as appropriate to satisfy the definition of ring C; and
(6) R 5 is (CO)NR 13 R 14 , (CO)OR 15 , (CO)SR 16 (SO 2 )NR 17 R 18 , (PO)(OR 19 )(OR 20 ) or CN, wherein R 13 , R 14 , R 15 , R 16 R 17 , R 18 R 19 and R 20 are independently hydrogen, (C1-C8) alkyl which can incorporate a (C3-C8) cycloalkyl, wherein the carbon linked to the oxygen of R 15 or the sulfur of R 16 has no more than secondary branching and , (C2-C6) hydroxyalkyl, aminoalkyl where the alkyl is C2 to C6 and the amino can be substituted with up to two (C1-C6) alkyls, arylalkyl wherein the alkyl is C1 to C6, heteroarylalkyl wherein the alkyl is C1 to C6, aryl or heteroaryl,
(a) wherein the aryl is phenyl or napthyl and the heteroaryl is a five-membered ring, a six-membered ring, a six-membered ring fused to a five-membered ring, or a six-membered ring fused to a six-membered ring, wherein the heteroaryl is aromatic and contains heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, with the remaining ring atoms being carbon,
(b) wherein the aryl, heteroaryl, aryl or arylalkyl or the heteroaryl of heteroarylalkyl can be substituted with up to three substituents selected from the group consisting of fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, amidosulfonyl which can have up to two (C1-C6) N-alkyl substitutions, (C1-C6) alkyl, (C2-C6) alkenyl, (C1-C6) alkylamine, dialkylamine wherein each alkyl is independently C1 to C6, amino, (C1-C6) alkoxy, (C2-C7) alkanoyl, (C2-C7) alkanoyloxy, trifluoromethoxy, hydroxycarbonyl, (C2-C7) alkyloxycarbonyl, aminocarbonyl that can be N-substituted with up to two (C1-C6) alkyl, (C1-C6) alkylsulfonyl, amidino that can substituted for hydrogen with up to three (C1-C6) alkyl, or methylenedioxy or ethylenedioxy with the two oxygens bonded to adjacent positions on the aryl or heteroaryl ring structure, which methylenedioxy or ethylenedioxy can be substituted with up to two (C1-C6) alkyl,
(c) wherein R 13 and R 14 together with the nitrogen to which they are bonded can form a 5 to 7-membered ring that can contain one additional heteroatom selected from oxygen and sulfur.
Yet other suitable agents identified as above include those wherein the agent is of the following formula I or II: ##STR3## or a pharmaceutically acceptable salt thereof, wherein: (1) X is nitrogen or carbon;
(2) Ar 1 is aryl, heteroaryl, arylalkyl wherein the alkyl is C1 to C2, or heteroarylalkyl wherein the alkyl is C1 to C2, and Ar 2 is aryl, heteroaryl, aryloxy, heteroaryloxy, arylalkyl wherein the alkyl is C1 to C2, heteroarylalkyl wherein the alkyl is C1 to C2, arylmethoxy, heteroarylmethoxy, arylthio, heteroarylthio, arylmethylthio, heteroarylmethylthio, or either Ar--N(R 6 )--or Ar--CH 2 --N(R 6* )--, wherein R 6 and R 6* are hydrogen or (C1-C6) alkyl and Ar can be aryl or heteroaryl,
(a) wherein when X is nitrogen Ar 2 is not aryloxy, heteroaryloxy, arylmethoxy, heteroarylmethoxy, arylthio, heteroarylthio, arylmethylthio, heteroarylmethylthio, Ar--N(R 6 )-- or Ar--CH 2 --N(R 6* )--,
(b) wherein the aryl of Ar 1 or Ar 2 is phenyl or naphthyl,
(c) wherein the heteroaryl of Ar 1 or Ar 2 comprises a five-membered ring, a six-membered ring, a six-membered ring fused to a five-membered ring, or a six-membered ring fused to a six-membered ring, wherein the heteroaryl is aromatic and contains heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, with the remaining ring atoms being carbon,
(d) wherein the aryl or heteroaryl of Ar 1 and Ar 2 together can be substituted with up to six substituents selected from the group consisting of fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, amidosulfonyl which can have up to two (C1-C6) N-alkyl substitutions, (C1-C6) alkyl, (C2-C6) alkenyl, amino, (C1-C6) alkylamino, dialkylamino wherein each alkyl is independently C1 to C6, (C1-C6) alkoxy, (C2-C7) alkanoyl, (C2-C7) alkanoyloxy, trifluoromethoxy, hydroxycarbonyl, (C2-C7) alkyloxycarbonyl, aminocarbonyl that can be substituted for hydrogen with up to two (C1-C6) alkyl, (C1-C6) alkylsulfonyl, amidino that can independently substituted for hydrogen with up to three (C1-C6) alkyl, or methylenedioxy or ethylenedioxy with the two oxygens bonded to adjacent positions on the aryl or heteroaryl ring structure, which methylenedioxy or ethylenedioxy can be substituted with up to 2 (C1-C6) alkyl,
(i.) wherein such substitutions to the aryl or heteroaryl of Ar 1 and Ar 2 can be combined to form a second bridge between Ar 1 and Ar 2 comprising (1) (C1-C2) alkyl or alkenyl, which can be substituted with one or more (C1-C6) alkyl, (2) sulfur, (3) oxygen, (4) amino, which can be substituted for hydrogen with one (C1-C6) alkyl, (5) carbonyl, (6) --CH 2 C(═O)--, which can be substituted for hydrogen with up to two (C1-C6) alkyl, (7) --C(═O)--O--, (8) --CH 2 --O--, which can be substituted for hydrogen with up to two (C1-C6) alkyl, (9) --C(═O)--N(R 24 )--, wherein R 24 is hydrogen or (C1-C6) alkyl, (10) --CH 2 --NH--, which can be substituted for hydrogen with up to three (C1-C6) alkyl, or (11) --CH═N--, which can be substituted for hydrogen with (C1-C6) alkyl, or wherein the aryls or heteroaryls of Ar 1 and Ar 2 can be directly linked by a single bond;
(3) R 1 comprises (a) a single bond or double bond, (b) a straight-chained (C1-C3) aliphatic group, (c) ═N--O--(CH 2 CH 2 )--when X is carbon, wherein the unmatched double bond is linked to X, or (d) --O--R 8 or --S--R 8* when X is carbon and Ar 2 is neither Ar--N(R 6 )-- nor Ar--CH 2 --N(R 6* )--, wherein either R 8 or R 8* is a single bond, (C1-C3) alkylene or (C2-C3) alkenylene and O or S is bonded to X,
(i.) wherein R 1 can be substituted with up to one hydroxy, up to one (C1-C6) alkoxy or up to one (C2-C7) alkanoyloxy, with up to two (C1-C6) alkyl, with up to one oxo, up to one (C1-C6) alkylidene, with the proviso that the hydroxy, alkoxy, alkanoyloxy or oxo substituents are not bonded to a carbon that is bonded to a nitrogen or oxygen,
(ii.) wherein the alkyl or alkylidene substituents of R 1 can be linked to form a 3 to 7-membered ring,
(iii.) wherein if X is nitrogen, X is linked to R 1 by a single bond and the terminal carbon of R 1 that links R 1 to N is saturated;
(4) R 2 (a) is not present when X is nitrogen, (b) is hydrogen, (C1-C6) alkyl, (C1-C6) alkoxy, cyano, (C2-C7) alkanoyl, aminocarbonyl, (C1-C6) alkylaminocarbonyl or dialkylaminocarbonyl wherein each alkyl is independently C1-C6, (c) comprises, where R 1 is not --O--R 8 , hydroxy, fluoro, chloro, bromo or(C2-C7) alkanoyloxy, (d) forms a double bond with an adjacent carbon or nitrogen from R 1 ;
(5) R 3 is a single bond or (C1-C2) alkyl or alkenyl;
(6) R 18 is a single bond or (C1-C3) alkyl or alkenyl; (7) wherein ring D is a 3 to 8-membered ring, a 3 to 8-membered ring substituted with a 3 to 6-membered spiro ring, or a 3 to 8-membered ring fused with a 5 to 6-membered ring, wherein the fused ring lacking the illustrated tertiary nitrogen can be aromatic or heteroaromatic, wherein for each component ring of ring D there are up to two heteroatoms selected from oxygen, sulfur or nitrogen, including the illustrated nitrogen, and the rest carbon, with the proviso that the ring atoms include no quaternary nitrogens, with the proviso that, in saturated rings, ring nitrogen atoms are separated from other ring heteroatoms by at least two intervening carbon atoms,
(a) wherein the carbon and nitrogen ring atoms of ring D can be substituted with up to three substituents selected from (C1-C6) alkyl, (C2-C6) alkenylene, cyano, nitro, trifluoromethyl, (C2-C7) alkyloxycarbonyl, (C1-C6) alkylidene, hydroxyl, (C1-C6) alkoxy, oxo, hydroxycarbonyl, aryl wherein the aryl is as defined for Ar 1 or heteroaryl wherein the heteroaryl is as defined for Ar 1 , with the proviso that ring atoms substituted with alkylidene, hydroxycarbonyl or oxo are carbon, with the further proviso that ring atoms substituted with hydroxyl or alkoxy are separated from other ring heteroatoms by at least two intervening carbon atoms,
(b) and wherein G is a required to satisfy the definition of ring D;
(8) wherein ring E is a 3 to 8-membered ring, a 3 to 8-membered ring substituted with a 3 to 6-membered spiro ring, or a 3 to 8-membered ring fused with a 5 to 6-membered ring, wherein the fused ring lacking the illustrated tertiary nitrogen can be aromatic or heteroaromatic, wherein for each component ring of ring E there are up to two heteroatoms selected from oxygen, sulfur or nitrogen, including the illustrated nitrogen, and the rest carbon, with the proviso that the ring atoms include no quaternary nitrogens, with the proviso that, in saturated rings, ring nitrogen atoms are separated from other ring heteroatoms by at least two intervening carbon atoms,
(a) wherein the carbon and nitrogen ring atoms of ring E can be substituted with up to three substituents selected from (C1-C6) alkyl, (C2-C6) alkenylene, cyano, nitro, trifluoromethyl, (C2-C7) alkyloxycarbonyl, (C1-C6) alkylidene, hydroxyl, (C-C6) alkoxy, oxo, hydroxycarbonyl, (C1-C6) alkoxycarbonyl, aryl wherein the aryl is as defined for Ar 1 or heteroaryl wherein the heteroaryl is as defined for Ar 1 with the proviso that ring atoms substituted with alkylidene, hydroxycarbonyl or oxo are carbon, with the further proviso that ring atoms substituted with hydroxyl or alkoxy are separated from other ring heteroatoms by at least two intervening carbon atoms;
(b) and wherein G * is a required to satisfy the definition of ring E;
(9) R 19 (a) forms a double bond with R 1 , R 3 or G, (b) is hydrogen (c) is (C1-C3) alkyl or alkylene, or (d) is incorporporated into a fused ring;
(10) R 4 and R 4* are independently hydrogen or (C1-C6) alkyl that can be bonded to complete a 3 to 7-membered ring, or one of R 4 and R 4* can be (C1-C6) hydroxyalkyl; and
(11) R 5 is (CO)NR 13 R 14 , (CO)OR 15 , (CO)SR 16 , (SO 2 )NR 17 R 18 , (PO)(OR 21 )(OR 20 ) or CN, wherein R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 and R 20 are independently hydrogen, (C1-C8) alkyl which can incorporate a (C3-C8) cycloalkyl, wherein the carbon linked to the oxygen of R 15 or the sulfur of R 16 has no more than secondary branching and , (C2-C6) hydroxyalkyl, aminoalkyl where the alkyl is C2 to C6 and the amino can be substituted with up to two (C1-C6) alkyls, arylalkyl wherein can be substituted with up to two (C1-C6) alkyls, arylalkyl wherein the alkyl is C1 to C6, heteroarylalkyl wherein the alkyl is C1 to C6, aryl or heteroaryl,
(a) wherein the aryl is phenyl or napthyl and the heteroaryl is a five-membered ring, a six-membered ring, a six-membered ring fused to a five-membered ring, or a six-membered ring fused to a six-membered ring, wherein the heteroaryl is aromatic and contains heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, with the remaining ring atoms being carbon,
(b) wherein the aryl, heteroaryl, aryl or arylalkyl or the heteroaryl of heteroarylalkyl can be substituted with up to three substituents selected from the group consisting of fluoro, chloro, bromo, nitro, cyano, trifluoromethyl, amidosulfonyl which can have up to two (C1C6) N-alkyl substitutions, (C1-C6) alkyl, (C2-C6) alkenyl, (C1-C6) alkylamine, dialkylamine wherein each alkyl is independently C1 to C6, amino, (C1-C6) alkoxy, (C2-C7) alkanoyl, (C2-C7) alkanoyloxy, trifluoromethoxy, hydroxycarbonyl, (C2-C7) alkyloxycarbonyl, aminocarbonyl that can be N-substituted with up to two (C1-C6) alkyl, (C1-C6) alkylsulfonyl, amidino that can substituted with up to three (C1-C6) alkyl, or methylenedioxy or ethylenedioxy with the two oxygens bonded to adjacent positions on the aryl or heteroaryl ring structure, which methylenedioxy or ethylenedioxy can be substituted with up to two (C1-C6) alkyl, and
(c) wherein R 13 and R 14 together with the nitrogen can form a 5 to 7-membered ring that can contain one additional heteroatom selected from oxygen and sulfur.
Some compounds that inhibit GlyT-1 or GlyT-2 mediated transport also bind to the glycine binding site on the NMDA receptor. Such binding can be identified by a binding assay whereby, for example, radiolabelled glycine is placed in contact with a preparation of NMDA receptors, such as can be prepared from neuronal cells or brain tissue. See, for example, Grimwood et al., Molec. Pharmacol., 41, 923 -930 (1992). In particular, one can prepare such NMDA receptors by isolating a membrane fraction from selected brain tissue of a suitable animal. Suitable brain tissue includes, but is not limited to, cortices and hippocampi, as isolated from any mammal. A membrane fraction can be prepared therefrom using conventional means, and includes, for example, methods of homogenization and centrifugation. The NMDA receptor located in such membranes is treated using mild detergent, such as about 0.1% to about 0.5% saponin, to remove any endogenous glycine or glutamate. The glycine used in such an assay is radiolabelled with any suitable isotope, such as 14 C or 3 H.
Specific binding of the radiolabelled glycine is then determined by subtracting the quantified radioactivity due to non-specific binding from that which is due to total (i.e., specific and non-specific) binding of the radiolabelled glycine. The radioactivity due to non-specific binding is determined by quantifying the amount of radiolabel associated with an NMDA receptor-containing membrane fraction that has been contacted with radiolabelled glycine and with at least a 100-fold excess of non-radiolabelled or "cold" glycine. The radioactivity due to total binding of the radiolabelled glycine is determined by quantifying the amount of radiolabel bound to the NMDA receptor preparation in the absence of non-radiolabeled glycine. One can also measure binding to the glycine site on the NMDA receptor using labeled analogs of amino acids, such as, for example, dichlorokynurenic acid or L-689,560. See Grimwood et al., Molecular Pharmacol., 49, 923-930 (1992).
Another way to measure binding of a compound to the glycine site on the NMDA receptor is by measuring the compound's ability to modulate the binding of [ 3 H]MK-801 to the NMDA receptor. MK-801 binds to the NMDA receptor at a different site than does glycine, but binding of glycine or other ligands to the glycine site can allosterically modulate the binding of MK-801. An advantage of this technique is that it allows one to distinguish compounds having agonist activity from those having antagonist activity at the NMDA-receptor-glycine binding site. In particular, compounds having agonist activity in this assay enhance MK-801 binding; conversely, compounds having antagonist activity inhibit MK-801 binding. Sterner and Calligaro, Soc. Neurosci. Abstr., 21, 351 (1995); Calligaro et al., J. Neurochem., 60, 2297-2303 (1993).
A functional ion-flux assay used to measure the effect of compounds identified by the present invention relates to the ability to enhance or inhibit calcium flux through the NMDA receptor. This test is performed on suitable cell cultures that have membrane-bound NMDA receptors and glycine transporters. Such cells include neuronal cells generally, including those of the central nervous system, including brain, and cell lines derived therefrom, and any other cell that has been induced or transfected to express NMDA receptors. Calcium used in such a test is commonly the 45 Ca isotope, although other calcium measuring techniques can be used as well, such as calcium-associated fluorescence and the like. However the calcium is monitored, calcium flux is enhanced or inhibited as a result of the discrete addition of a compound of the present invention. An advantage of this system is that it allows one to monitor the net effect on NMDA receptor function of a compound that interacts with the glycine site on the NMDA receptor and the glycine transporter.
GlyT-1 inhibitors that are also NMDA receptor agonists act to alleviate schizophrenia and enhance cognition both by increasing glycine concentrations at the NMDA receptor-expressing synapses via inhibition of the glycine transporter, and via directly enhancing NMDA receptor activity. Glycine transporter inhibitors that are also NMDA receptor antagonists can nonetheless retain activity in schizophrenia and enhancing cognition, if the increase in glycine due to glycine transport inhibition prevails over the NMDA antagonism. Where the NMDA receptor antagonist activity prevails over the effect of increased extracellular glycine resulting from inhibition of the glycine transporter, these compounds are useful in limiting the cell damage and cell death arising after stroke or as a consequence of neurodegenerative diseases such as Alzheimer's, Parkinson's, AIDS dementia, Huntington's, and the like. See, for example, Choi, supra; Coyle and Puttfarcken, supra; Lipton and Rosenberg, supra; Brennan, Chem. Eng. News (May 13, 1996), pp. 41-47; Leeson, in Drug Design For Neuroscience (Alan P. Kozikowski, ed., 1993), pp. 339-383.
As discussed above, the compounds of the invention have a number of pharmacological actions. The relative effectiveness of the compounds can be assessed in a number of ways, including the following:
1. Comparing the activity mediated through GlyT-1 and GlyT-2 transporters. This testing identifies compounds (a) that are more active against GlyT-1 transporters and thus more useful in treating or preventing schizophrenia, increasing cognition and enhancing memory or (b) that are more active against GlyT-2 transporters and thus more useful in treating or preventing epilepsy, pain or spasticity.
2. Testing for NMDA receptor binding. This test establishes whether there is sufficient binding at this site, whether antagonist or agonist activity, to warrant further examination of the pharmacological effect of such binding.
3. Testing the activity of the compounds in enhancing or diminishing calcium fluxes in primary neuronal tissue culture. A test compound that increases calcium flux either (a) has little or no antagonist activity at the NMDA receptor and should not affect the potentiation of glycine activity through GlyT-1 transporter inhibition or (b), if marked increases are observed over comparison with GlyT-1 inhibitors that have little direct interaction with NMDA receptors, then the compound is a receptor agonist. In either of the above-described cases, the test confirms activity in treating or preventing schizophrenia, increasing cognition, or enhancing memory. In contrast, a test compound that decreases calcium flux has a net effect wherein receptor antagonist activity predominates over any activity the compound has in increasing glycine activity through inhibiting glycine transport. In this case, the test confirms activity in limiting or preventing the cell damage and cell death arising after stroke or other ischemia-inducing conditions, or in limiting or preventing the cell damage associated with neurodegenerative diseases.
The following examples further illustrate the present invention, but, of course, should not be construed as in any way limiting its scope.
EXAMPLE 1
This example sets forth methods and materials used for growing and transfecting QT-6 cells.
QT-6 cells were obtained from American Type Culture Collection (Accession No. ATCC CRL-1708). Complete QT-6 medium for growing QT-6 is Medium 199 (Sigma Chemical Company, St. Louis, Mo.; hereinafter "Sigma") supplemented to be 10% tryptose phosphate; 5% fetal bovine serum (Sigma); 1% penicillin-streptomycin (Sigma); and 1% sterile dimethylsulfoxide (DMSO; Sigma). Other solutions required for growing or transfecting QT-6 cells included:
DNA/DEAE Mix: 450 μl TBS, 450 μl DEAE Dextran (Sigma), and 100 μl of DNA (4 μg) in TE, where the DNA includes GlyT-1a, GlyT-1b, GlyT-1c, or GlyT-2, in a suitable expression vector. The DNA used was as defined below.
PBS: Standard phosphate buffered saline, pH 7.4 including 1 mM CaCl 2 and 1 mM MgCl 2 sterilized through 0.2μ filter.
TBS: One ml of Solution B, 10 ml of Solution A; brought to 100 ml with distilled H 2 O; filter-sterilized and stored at 4° C.
TE: 0.01 M Tris, 0.001 M EDTA, pH 8.0.
DEAE dextran: Sigma, #D-9885. A stock solution was prepared consisting of 0.1% (1 mg/ml) of the DEAE dextran in TBS. The stock solution was filter sterilized and frozen in 1 ml aliquots.
Chloroguine: Sigma, #C-6628. A stock solution was prepared consisting of 100 mM chloroquine in H 2 O. The stock solution was filter-sterilized and stored in 0.5 ml aliquots, frozen.
______________________________________ NaCl 8.00 g KCl 0.38 g Na.sub.2 HPO.sub.4 0.20 g Tris base 3.00 g______________________________________
The solution was adjusted to pH 7.5 with HCl, brought to 100.0 ml with distilled H 2 O, and filter-sterilized and stored at room temperature.
______________________________________ CaCl.sub.2.2H.sub.2 O 1.5 g MgCl.sub.2.6H.sub.2 O 1.0 g______________________________________
The solution was brought to 100 ml with distilled H 2 O, and filter-sterilized; the solution was then stored at room temperature.
HBSS: 150 mM NaCl, 20 mM HEPES, 1 mM CaCl 2 , 10 mM glucose, 5 mM KCl, 1 mM MgCl 2 H 2 O; adjusted with NaOH to pH 7.4.
Standard growth and passaging procedures used were as follows: Cells were grown in 225 ml flasks. For passaging, cells were washed twice with warm HBSS (5 ml each wash). Two ml of a 0.05% trypsin/EDTA solution was added, the culture was swirled, then the trypsin/EDTA solution was aspirated quickly. The culture was then incubated about 2 minutes (until cells lift off), then 10 ml of QT-6 media was added and the cells were further dislodged by swirling the flask and tapping its bottom. The cells were removed and transferred to a 15 ml conical tube, centrifuged at 1000×g for 10 minutes, and resuspended in 10 ml of QT-6 medium. A sample was removed for counting, the cells were then diluted further to a concentration of 1×10 5 cells/ml using QT-6 medium, and 65 ml of the culture was added per 225 ml flask of passaged cells.
Transfection was accomplished using cDNAs prepared as follows:
The rat GlyT-2 (rGlyT-2) clone used contains the entire sequence of rGlyT-2 cloned into pBluescript SK+ (Stratagene) as an Eco RI-Hind III fragment, as described in Liu et al., J. Biol. Chem. 268, 22802-22808 (1993). GlyT-2 was then subcloned into the pRc/RSV vector as follows: A PCR fragment corresponding to nucleotides 208 to 702 of the rGlyT-2 sequence [SEQ ID NO:4] was amplified by PCR using the oligonucleotide: 5'GGGGGAAGCTTATGGATTGCAGTGCTCC 3' [SEQ ID NO:5] as the 5'primer and the oligonucleotide:
5'GGGGGGGTACCCAACACCACTGTGCTCTG 3' [SEQ ID NO:6] as the 3' primer. This created a Hind III site immediately upstream of the translation start site. This fragment, which contained a Kpn I site at the 3' end, along with a Kpn 1-Pvu II fragment containing the remainder of the coding sequence of rGlyT-2, were cloned into pBluescript SK+ previously digested with Hind III and Sma I, in a three part ligation. A Hind III-Xba I fragment from this clone was then subcloned into the pRc/RSV vector. The resulting construct contains nucleotides 208 to 2720 of the rGlyT-2 nucleic acid [SEQ ID NO:4] in the pRc/RSV expression vector.
The human GlyT-1a (hGlyT-1a) clone used contains the sequence of hGlyT-1a [SEQ ID NO:1]from nucleotide position 183 to 2108 cloned into the pRc/CMV vector (Invitrogen, San Diego, Calif.) as a Hind III-Xba I fragment as described in Kim et al., Mol. Pharmacol., 45 608-617, 1994. This cDNA encoding GlyT-1a actually contained the first 17 nucleotides (corresponding to the first 6 amino acids) of the GlyT-1a sequence from rat. To determine whether the sequence of human GlyT-1a was different in this region, the 5' region of hGlyT-1a from nucleotide 1 to 212 was obtained by rapid amplification of cDNA end using the 5' RACE system supplied by Gibco BRL (Gaithersburg, Md.). The gene specific primer: 5'CCACATTGTAGTAGATGCCG 3' [SEQ ID NO:7], corresponding to nucleotides 558 to 539 of the hGlyT-1a sequence [SEQ ID NO:1], was used to prime cDNA synthesis from human brain mRNA, and the gene specific primer: 5'GCAAACTGGCCGAAGGAGAGCTCC 3' [SEQ ID NO:8], corresponding to nucleotides 454 to 431 of the hGlyT-1a sequence [SEQ ID NO:1], was used for PCR amplification. Sequencing of this 5' region of GlyT-1a confirmed that the first 17 nucleotides of coding sequence are identical in human and rat GlyT-1a.
The human GlyT-1b (hGlyT-1b) clone used contains the sequence of hGlyT-1b [SEQ ID NO:2] from nucleotide position 213 to 2274 cloned into the pRc/CMV vector as a Hind III-Xba I fragment as described in Kim et al., supra.
The human GlyT-1c (hGlyT-1c) clone used contains the sequence of hGlyT-1c [SEQ ID NO:3] from nucleotide position 213 to 2336 cloned into the pRc/CMV vector (Invitrogen) as a Hind III-Xba I fragment as described in Kim et al., supra. The Hind III-Xba fragment of hGlyT-1c from this clone was then subcloned into the pRc/RSV vector. Transfection experiments were performed with GlyT-1c in both the pRc/RSV and pRc/CMV expression vectors.
The following four day procedure for the tranfections was used:
On day 1, QT-6 cells were plated at a density of 1×10 6 cells in 10 ml of complete QT-6 medium in 100 mm dishes.
On day 2, the medium was aspirated and the cells were washed with 10 ml of PBS followed by 10 ml of TBS. The TBS was aspirated, then 1 ml of the DEAE/DNA mix was added to the plate. The plate was swirled in the hood every 5 minutes. After 30 minutes, 8 ml of 80 μM chloroquine in QT-6 medium was added and the culture was incubated for 2.5 hours at 37° C. and 5% CO 2 . The medium was then aspirated and the cells were washed two times with complete QT-6 medium, then 100 ml complete QT-6 medium was added and the cells were returned to the incubator.
On day 3, the cells were removed with trypsin/EDTA as described above, and plated into the wells of 96-well assay plates at approximately 2×10 5 cells/well.
On day 4, glycine transport was assayed as described in Example 2.
EXAMPLE 2
This example illustrates a method for the measurement of glycine uptake by transfected cultured cells.
Transient GlyT-transfected cells or control ("mock") cells grown in accordance with Example 1 were washed three times with HEPES buffered saline (HBS). The mock cells were treated precisely as the GlyT-transfected cells except that the transfection procedure omitted any cDNA. The cells were incubated 10 minutes at 37° C., after which a solution was added containing 50 nM [ 3 H] glycine (17.5 Ci/mmol) and either (a) no potential competitor, (b) 10 mM nonradioactive glycine or (c) a concentration of a candidate drug. A range of concentrations of the candidate drug was used to generate data for calculating the concentration resulting in 50% of the effect (e.g., the IC 50 s, which are the concentrations of drug inhibiting glycine uptake by 50%). The cells were then incubated another 20 minutes at 37° C., after which the cells were aspirated and washed three times with ice-cold HBS. The cells were harvested, scintillant was added to the cells, the cells were shaken for 30 minutes, and the radioactivity in the cells was counted using a scintillation counter. Data were compared between the cells contacted or not contacted by a candidate agent, and between cells having GlyT-1 activity versus cells having GlyT-2 activity, depending on the assay being conducted.
Positive control results are depicted in the bar graphs of FIGS. 1A and 1B, in which [ 3 H] glycine uptake is shown for mock, GlyT-1a, GlyT-1b, GlyT-1c, and GlyT-2 transformed cells. The results of the positive controls are presented as means±SEM of a representative experiment performed in triplicate. All cell cultures transformed with any of the glycine transporters evidenced a significant increase in glycine transport activity as compared to non-transfected control cells.
EXAMPLE 3
This example illustrates the application of the method of Example 2, and the identification thereby of certain agents that regulate selectively the GlyT-1 or the GlyT-2 transporter, with respect to each other.
The agents recited below were tested for inhibition or enhancement of glycine transport in QT-6 cells that were transfected with pRc/CMV containing GlyT-1c [SEQ ID NO:3] or GlyT-2 [SEQ ID NO:4], and exhibited transient expression of GlyT-1c or GlyT-2, respectively, in accordance with the procedures of Examples 1 and 2 above. ##STR4## The data obtained with these compounds are as follows:
______________________________________Compound Effect Via GlyT-1c* Effect Via GlyT-2*______________________________________ZA pIC.sub.50 = 6.04 pIC.sub.50 = 5.51 ZB pIC.sub.50 = 5.37 pIC.sub.50 = 4.77 ZC pIC.sub.50 = 5.19 pIC.sub.50 = 4.85 ZD pIC.sub.50 = 5.02 pIC.sub.50 = 4.71 ZE pIC.sub.50 = 4.89 pIC.sub.50 = 4.68 ZF pIC.sub.50 = 4.67 pIC.sub.50 = 4.84______________________________________ *Transfected into QT6 cells. The term "pIC.sub.50 " equals log of IC.sub.50, wherein IC.sub.50 is the concentration of drug inhibiting glycine uptake by 50%.
Accordingly, compounds ZA, ZB, ZC, ZD, and ZE are each selective for GlyT-1c relative to GlyT-2, whereas compound ZF shows the reverse selectivity.
EXAMPLE 4
This example illustrates binding assays to measure interaction of compounds with the glycine site on the NMDA receptor.
Direct binding of [ 3 H] glycine to the NMDA-glycine site was performed according to the method of Grimwood et al., Molecular Pharmacology, 41, 923-930 (1992); Yoneda et al., J. Neurochem, 62, 102-112 (1 994).
Preparation of membranes for the binding test required application of a series of standard methods. Unless otherwise specified, tissues and homogenates were kept on ice and centrifugations were conducted at 4° C. Homogenizations were conducted with an effort to minimize resulting rise in tissue/homogenate temperature. The membrane preparation included the following steps:
1. Sacrifice and decapitate four rats; remove cortices and hippocampi.
2. Homogenize tissue in twenty volumes of 0.32 M sucrose/5 mM Tris-Acetate (pH 7.4) with 20 strokes of a glass/teflon homogenizer.
3. Centrifuge tissue at 1000×g, 10 minutes. Save supernatant. Resuspend pellet in small volume of buffer and homogenize again. Centrifuge the homogenized pellet and combine the supernatant with the previous supernatant.
4. Centrifuge the combined supernatants at 40,000×g, for 30 minutes. Discard the supernatant.
5. Resuspend the pellet in 20 volumes of 5 mM Tris-Acetate (pH 7.4). Stir the suspension on ice for one hour. Centrifuge the suspension at 40,000×g for 30 minutes. Discard the supernatant and freeze the pellet for at least 24 hours.
6. Resuspend the pellet from step 5 in Tris Acetate buffer (5 mM, pH 7.4) containing 0.1% saponin (w/v; Sigma Chemical Co., St. Louis) to a protein concentration of 1 mg/ml. Leave on ice for 20 minutes. Centrifuge the suspension at 40,000×g for 30 minutes. Resuspend the pellet in saponin-free buffer and centrifuge again. Resuspend the pellet in Tris-Acetate buffer at a concentration of 10 mg/ml and freeze in aliquots.
7. On day three, remove an aliquot of membranes and thaw on ice. Dilute the suspension into 10 ml Tris-Acetate buffer and centrifuge at 40,000×g for 30 minutes. Repeat the wash step twice more for a total of 3 washes. Resuspend the final pellet at a concentration of 1 mg/ml in glycine-free Tris-Acetate buffer.
The binding test was performed in Eppendorf tubes containing approximately 150 μg of membrane protein and 50 nM [ 3 H] glycine in a volume of 0.5 ml. Non-specific binding was determined with 1 mM glycine. Drugs were dissolved in assay buffer (50 mM Tris-acetate, pH 7.4) or DMSO (final concentration of 0.1%). Membranes were incubated on ice for 30 minutes and bound radioligand was separated from free radioligand by filtration on Whatman GF/B glass fiber filters or by centrifugation (18,000×g, 20 min). Filters were washed three times quickly with ice-cold 5 mM Tris-acetate buffer. Filters were dried and placed in scintillation tubes and counted. Pellets were dissolved in deoxycholate/NaOH (0.1 N) solution overnight, neutralized and radioactivity was determined by scintillation counting.
A second binding test for the NMDA-glycine site used [ 3 H] dichlorokynurenic acid (DCKA) and membranes prepared as above. See, Yoneda et al., J. Neurochem., 60, 634-645 (1993). The binding assay was performed as described for [ 3 H]glycine above except that [ 3 H]DCKA was used to label the glycine site. The final concentration of [ 3 H]DCKA was 10 nM, and the assay was performed for 10 minutes on ice.
A third binding test used for the NMDA-glycine site used indirect assessment of affinity of ligands for the site by measuring the binding of [ 3 H]MK-801 (dizocilpine; Palmer and Burns, J. Neurochem., 62, 187-196 (1994)). Preparation of membranes for the test was the same as above. The binding assay allowed separate detection of antagonists and agonists.
The third binding test was operated to identify antagonists as follows: 100 μg of membranes were added to wells of a 96-well plate, along with glutamate (10 μM) and glycine (200 nM) and various concentrations of the ligand to be tested. The assay was started by the addition of 2.5 nM [ 3 H]MK-801 (23.9 Ci/mmol), which binds to the ion channel associated with NMDA receptors. The final volume of the assay was 200 μl. The assay was performed for 1 hour at room temperature. Bound radioactivity was separated from free by filtration, using a TOMTEC harvester. Antagonist activity was indicated by decreasing radioactivity associated with the NMDA receptor with increasing concentration of the tested ligand. Results of a positive control of this test are depicted in the graph of FIG. 2A, wherein the effect of varying concentrations of the glycine-site antagonist L-689,560 (represented as the log of the molar concentration of L-689,560 on the x-axis) is shown with respect to the resultant binding of [ 3 H]MK-801, indicated in counts per minute on the y-axis. The concentration of antagonist resulting in about a 50% effect was about 5×10 -7 M.
The third binding test was operated to identify agonists by performing the test as above, except that the concentration of glycine was 2 nM. Agonist activity was indicated by increasing radioactivity associated with the NMDA receptor with increasing concentration of the tested ligand. Results of a positive control of this test are depicted in the graph of FIG. 2B, wherein the effect of varying concentrations of glycine (x-axis, log of the molar concentration of glycine) is shown with respect to the resultant binding of [ 3 H]MK-801 in counts per minute (y-axis). The concentration of agonist (here, glycine itself) resulting in about a 50% effect was about 10 -6 M.
EXAMPLE 5
This example illustrates a protocol for measuring calcium flux in primary neuronal cells, which is an indication of NMDA receptor activation.
The calcium flux measurement is performed in primary neuronal cell cultures, which are prepared from rat fetal cortices dissected from pregnant rats using standard procedures and techniques that require sterile dissecting equipment, a microscope and defined medium. The protocol used was adapted from Lu et al., Proc. Nat'l. Acad. Sci. USA, 88, 6289-6292 (1991).
Defined medium is prepared in advance in accordance with the following recipe:
______________________________________Components Source (catalogue #) Final Concentration______________________________________D-glucose Sigma (G-7021) 0.6% transferrin Sigma (T-2252) 100 μg/ml insulin Sigma (I-5500) 25 μg/ml progesterone Sigma (P-6149) 20 nM putrescine Sigma (P-7505) 60 μM selenium Sigma (S-5261) 30 nM pen-strep.sup.▴ GIBCO (15070-014) 0.5 U-0.5 μg/ml L-glutamine* GIBCO (25030-016) 146 mg/l MEM.sup.∘ GIBCO (11095 or 500 ml/l 11090) F-12 GIBCO (11765) 500 ml/l______________________________________ .sup.▴ penstrep: 5,000 U/ml penicillin and 5,000 μg/ml steptomycin *add only when MEM without Lglutamine is used .sup.∘ with Lglutamine or without Lglutamine, respectively
Before starting the dissection, tissue culture plates were treated with polylysine (100 μg/ml for at least 30 minutes at 37° C.) and washed with distilled water. Also, a metal tray containing two sets of sterile crude dissecting equipment (scissors and tweezers) and several sets of finer dissecting tools was autoclaved. A pair of scissors and tweezers were placed into a sterile beaker with 70% alcohol and brought to the dissecting table. A petri dish with cold phosphate buffered saline (PBS) was placed on ice next to the place of dissection.
A pregnant rat (E15 or 16 on arrival from Hilltop Lab Animals (Scottdale, Pa.), E17 or 18 at dissection) was placed in a CO 2 /dry ice chamber until it was unconscious. The rat was removed, pinned to a backing, the area of dissection was swabbed with 70% alcohol, and skin was cut and removed from the area of interest. A second pair of scissors was used to cut through and remove the prenatal pups in their sacs. The string of sacs was placed into the cold PBS and transported to a sterile hood.
The prenatal pups were removed from the sacs and decapitated. The skulls were then removed and the brains were carefully dislodged and placed into a clean petri dish with cold PBS. At this point, it was necessary to proceed with a dissecting microscope. The brain was turned so that the cortices were contacting the plate and the tissue between the dissector and the cortex (striatum and other brain parts) was scooped out. The hippocampus and olfactory bulb were cut away from the cortex. Then the tissue was turned over and the meninges were removed with tweezers. The remaining tissue (cortex) was placed in a small petri dish with defined media.
The tissue was chopped with a scalpel and then triturated with a glass pipet that had been fire polished. The chopped, triturated tissue was then transferred to a sterile plastic tube and continued to be triturated with a glass pipet with a finer opening. Cells were counted in a suitable counting chamber. Cells were plated at roughly 200,000 cells/well in 500 μl of defined medium in 24-well plates. To inhibit glia growth, cultures were treated with 100 μM 5-flouro-2-deoxyuridine (FDUR, Sigma (F-0503)) or 50/μM uridine (Sigma (U-3003)) and 50 μM FDUR.
The cortical cultures for the standard calcium flux assay were grown in 24-well plates in the defined medium described above for 7 days and fed once with serum containing medium (10% heat inactivated fetal calf serum, 0.6% glucose in MEM) by exchanging half of the medium. Cultures were used after 12 days of incubation in vitro. The cultures were rinsed three times with HCSS (i.e. HEPES-buffered control salt solution, containing 120 mM NaCl, 5.4 mM KCl, 1.8 mM CaCl 2 , 25 mM HEPES, and 15 mM glucose, in HPLC water and adjusted to pH 7.4 by NaOH, which was also made in HPLC water). In the third wash, the culture was incubated at 37° C. for 20 to 30 minutes.
Solutions containing 45 Ca ++ (1.5×10 6 dpm/ml) and drugs for testing or controls were prepared in HCSS. Immediately before the above 45 Ca ++ solutions were added, cultures were washed twice with HCSS, and 250 μl of 45 Ca ++ solution per well was added, one plate at a time. The cultures were incubated for 10 minutes at room temperature, rinsed three times with HCSS, and 1 ml scintillation liquid per well was added, followed by shaking for at least 15 minutes. Retained radioactivity was counted in a scintillation counter.
Results of a standard calcium flux experiment are presented in FIG. 3. Primary neuronal cortical cell cultures were incubated with 45 Ca ++ alone (control), in the presence of NMDA (500 μM), or NMDA (500 μM) and the antagonist L689,560 (50 μM), as described above. Data presented in the bar graph of FIG. 3 show the accumulation of 45 Ca ++ , and are the means±SEM of a representative experiment (performed in triplicate) that was repeated with similar results. Accordingly, the results demonstrate that NMDA causes an increased accumulation of 45 Ca ++ , and that this effect is blocked by the glycine site antagonist L-689,560.
While this invention has been described with an emphasis upon preferred embodiments, it will be obvious to those of ordinary skill in the art that variations in the preferred compositions and methods may be used and that it is intended that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and scope of the invention as defined by the claims that follow the Sequence Listing.
__________________________________________________________________________# SEQUENCE LISTING - - - - (1) GENERAL INFORMATION: - - (iii) NUMBER OF SEQUENCES: 8 - - - - (2) INFORMATION FOR SEQ ID NO:1: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2136 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1: - - AGAGCCTCGG GAGGCTGATG CAACTTTCCC TTTAAGAAAG CCACCTGGGC GC -#ACCGCGGT 60 - - GCGGACCCAG CACGCCTGGG CCGGGGGCTG CAGCATGCTC TTGAGATCTG TG -#GCCTGAAA 120 - - GGCGCTGGAA GCAGAGCCTG TAAGTGTGGT CCCCGTCACC AGAGCCCCAA CC -#CACCGCCG 180 - - CCATGGTAGG AAAAGGTGCC AAAGGGATGC TGAATGGTGC TGTGCCCAGC GA -#GGCCACCA 240 - - AGAGGGACCA GAACCTCAAA CGGGGCAACT GGGGCAACCA GATCGAGTTT GT -#ACTGACGA 300 - - GCGTGGGCTA TGCCGTGGGC CTGGGCAATG TCTGGCGCTT CCCATACCTC TG -#CTATCGCA 360 - - ACGGGGGAGG CGCCTTCATG TTCCCCTACT TCATCATGCT CATCTTCTGC GG -#GATCCCCC 420 - - TCTTCTTCAT GGAGCTCTCC TTCGGCCAGT TTGCAAGCCA GGGGTGCCTG GG -#GGTCTGGA 480 - - GGATCAGCCC CATGTTCAAA GGAGTGGGCT ATGGTATGAT GGTGGTGTCC AC -#CTACATCG 540 - - GCATCTACTA CAATGTGGTC ATCTGCATCG CCTTCTACTA CTTCTTCTCG TC -#CATGACGC 600 - - ACGTGCTGCC CTGGGCCTAC TGCAATAACC CCTGGAACAC GCATGACTGC GC -#CGGTGTAC 660 - - TGGACGCCTC CAACCTCACC AATGGCTCTC GGCCAGCCGC CTTGCCCAGC AA -#CCTCTCCC 720 - - ACCTGCTCAA CCACAGCCTC CAGAGGACCA GCCCCAGCGA GGAGTACTGG AG -#GCTGTACG 780 - - TGCTGAAGCT GTCAGATGAC ATTGGGAACT TTGGGGAGGT GCGGCTGCCC CT -#CCTTGGCT 840 - - GCCTCGGTGT CTCCTGGTTG GTCGTCTTCC TCTGCCTCAT CCGAGGGGTC AA -#GTCTTCAG 900 - - GGAAAGTGGT GTACTTCACG GCCACGTTCC CCTACGTGGT GCTGACCATT CT -#GTTTGTCC 960 - - GCGGAGTGAC CCTGGAGGGA GCCTTTGACG GCATCATGTA CTACCTAACC CC -#GCAGTGGG 1020 - - ACAAGATCCT GGAGGCCAAG GTGTGGGGTG ATGCTGCCTC CCAGATCTTC TA -#CTCACTGG 1080 - - CGTGCGCGTG GGGAGGCCTC ATCACCATGG CTTCCTACAA CAAGTTCCAC AA -#TAACTGTT 1140 - - ACCGGGACAG TGTCATCATC AGCATCACCA ACTGTGCCAC CAGCGTCTAT GC -#TGGCTTCG 1200 - - TCATCTTCTC CATCCTCGGC TTCATGGCCA ATCACCTGGG CGTGGATGTG TC -#CCGTGTGG 1260 - - CAGACCACGG CCCTGGCCTG GCCTTCGTGG CTTACCCCGA GGCCCTCACA CT -#ACTTCCCA 1320 - - TCTCCCCGCT GTGGTCTCTG CTCTTCTTCT TCATGCTTAT CCTGCTGGGG CT -#GGGCACTC 1380 - - AGTTCTGCCT CCTGGAGACG CTGGTCACAG CCATTGTGGA TGAGGTGGGG AA -#TGAGTGGA 1440 - - TCCTGCAGAA AAAGACCTAT GTGACCTTGG GCGTGGCTGT GGCTGGCTTC CT -#GCTGGGCA 1500 - - TCCCCCTCAC CAGCCAGGCA GGCATCTATT GGCTGCTGCT GATGGACAAC TA -#TGCGGCCA 1560 - - GCTTCTCCTT GGTGGTCATC TCCTGCATCA TGTGTGTGGC CATCATGTAC AT -#CTACGGGC 1620 - - ACCGGAACTA CTTCCAGGAC ATCCAGATGA TGCTGGGATT CCCACCACCC CT -#CTTCTTTC 1680 - - AGATCTGCTG GCGCTTCGTC TCTCCCGCCA TCATCTTCTT TATTCTAGTT TT -#CACTGTGA 1740 - - TCCAGTACCA GCCGATCACC TACAACCACT ACCAGTACCC AGGCTGGGCC GT -#GGCCATTG 1800 - - GCTTCCTCAT GGCTCTGTCC TCCGTCCTCT GCATCCCCCT CTACGCCATG TT -#CCGGCTCT 1860 - - GCCGCACAGA CGGGGACACC CTCCTCCAGC GTTTGAAAAA TGCCACAAAG CC -#AAGCAGAG 1920 - - ACTGGGGCCC TGCCCTCCTG GAGCACCGGA CAGGGCGCTA CGCCCCCACC AT -#AGCCCCCT 1980 - - CTCCTGAGGA CGGCTTCGAG GTCCAGTCAC TGCACCCGGA CAAGGCGCAG AT -#CCCCATTG 2040 - - TGGGCAGTAA TGGCTCCAGC CGCCTCCAGG ACTCCCGGAT ATAGCACAGC TG -#CCAGGGGA 2100 - - GTGCCACCCC ACCCGTGCTC CACGAGAGAC TGTGAG - #- # 2136 - - - - (2) INFORMATION FOR SEQ ID NO:2: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2202 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: - - GCCCACACAC CCCACTCCAG CTCCGGAGCA CCCGTGCTGG GCTGCATGGG GA -#CTGGCCGG 60 - - AGGGGCAGGG CCAGGGGAGC GGGTAGGCAG AGCTTCGGGA GGAGATGAGG TG -#AAAGTAAT 120 - - TGACGCTGCC CAGCCCGGCA GTGGGAGAGG CAGGGGATGC GTCAGTGTCG CG -#CTGGAGCT 180 - - GGCAGAGGTG ATGAGCGGCG GAGACACGCG GGGCTGCGAT CGCTCGCCCC AG -#GATGGCCG 240 - - CGGCTCATGG ACCTGTGGCC CCCTCTTCCC CAGAACAGAA TGGTGCTGTG CC -#CAGCGAGG 300 - - CCACCAAGAG GGACCAGAAC CTCAAACGGG GCAACTGGGG CAACCAGATC GA -#GTTTGTAC 360 - - TGACGAGCGT GGGCTATGCC GTGGGCCTGG GCAATGTCTG GCGCTTCCCA TA -#CCTCTGCT 420 - - ATCGCAACGG GGGAGGCGCC TTCATGTTCC CCTACTTCAT CATGCTCATC TT -#CTGCGGGA 480 - - TCCCCCTCTT CTTCATGGAG CTCTCCTTCG GCCAGTTTGC AAGCCAGGGG TG -#CCTGGGGG 540 - - TCTGGAGGAT CAGCCCCATG TTCAAAGGAG TGGGCTATGG TATGATGGTG GT -#GTCCACCT 600 - - ACATCGGCAT CTACTACAAT GTGGTCATCT GCATCGCCTT CTACTACTTC TT -#CTCGTCCA 660 - - TGACGCACGT GCTGCCCTGG GCCTACTGCA ATAACCCCTG GAACACGCAT GA -#CTGCGCCG 720 - - GTGTACTGGA CGCCTCCAAC CTCACCAATG GCTCTCGGCC AGCCGCCTTG CC -#CAGCAACC 780 - - TCTCCCACCT GCTCAACCAC AGCCTCCAGA GGACCAGCCC CAGCGAGGAG TA -#CTGGAGGC 840 - - TGTACGTGCT GAAGCTGTCA GATGACATTG GGAACTTTGG GGAGGTGCGG CT -#GCCCCTCC 900 - - TTGGCTGCCT CGGTGTCTCC TGGTTGGTCG TCTTCCTCTG CCTCATCCGA GG -#GGTCAAGT 960 - - CTTCAGGGAA AGTGGTGTAC TTCACGGCCA CGTTCCCCTA CGTGGTGCTG AC -#CATTCTGT 1020 - - TTGTCCGCGG AGTGACCCTG GAGGGAGCCT TTGACGGCAT CATGTACTAC CT -#AACCCCGC 1080 - - AGTGGGACAA GATCCTGGAG GCCAAGGTGT GGGGTGATGC TGCCTCCCAG AT -#CTTCTACT 1140 - - CACTGGCGTG CGCGTGGGGA GGCCTCATCA CCATGGCTTC CTACAACAAG TT -#CCACAATA 1200 - - ACTGTTACCG GGACAGTGTC ATCATCAGCA TCACCAACTG TGCCACCAGC GT -#CTATGCTG 1260 - - GCTTCGTCAT CTTCTCCATC CTCGGCTTCA TGGCCAATCA CCTGGGCGTG GA -#TGTGTCCC 1320 - - GTGTGGCAGA CCACGGCCCT GGCCTGGCCT TCGTGGCTTA CCCCGAGGCC CT -#CACACTAC 1380 - - TTCCCATCTC CCCGCTGTGG TCTCTGCTCT TCTTCTTCAT GCTTATCCTG CT -#GGGGCTGG 1440 - - GCACTCAGTT CTGCCTCCTG GAGACGCTGG TCACAGCCAT TGTGGATGAG GT -#GGGGAATG 1500 - - AGTGGATCCT GCAGAAAAAG ACCTATGTGA CCTTGGGCGT GGCTGTGGCT GG -#CTTCCTGC 1560 - - TGGGCATCCC CCTCACCAGC CAGGCAGGCA TCTATTGGCT GCTGCTGATG GA -#CAACTATG 1620 - - CGGCCAGCTT CTCCTTGGTG GTCATCTCCT GCATCATGTG TGTGGCCATC AT -#GTACATCT 1680 - - ACGGGCACCG GAACTACTTC CAGGACATCC AGATGATGCT GGGATTCCCA CC -#ACCCCTCT 1740 - - TCTTTCAGAT CTGCTGGCGC TTCGTCTCTC CCGCCATCAT CTTCTTTATT CT -#AGTTTTCA 1800 - - CTGTGATCCA GTACCAGCCG ATCACCTACA ACCACTACCA GTACCCAGGC TG -#GGCCGTGG 1860 - - CCATTGGCTT CCTCATGGCT CTGTCCTCCG TCCTCTGCAT CCCCCTCTAC GC -#CATGTTCC 1920 - - GGCTCTGCCG CACAGACGGG GACACCCTCC TCCAGCGTTT GAAAAATGCC AC -#AAAGCCAA 1980 - - GCAGAGACTG GGGCCCTGCC CTCCTGGAGC ACCGGACAGG GCGCTACGCC CC -#CACCATAG 2040 - - CCCCCTCTCC TGAGGACGGC TTCGAGGTCC AGTCACTGCA CCCGGACAAG GC -#GCAGATCC 2100 - - CCATTGTGGG CAGTAATGGC TCCAGCCGCC TCCAGGACTC CCGGATATAG CA -#CAGCTGCC 2160 - - AGGGGAGTGC CACCCCACCC GTGCTCCACG AGAGACTGTG AG - # - #2202 - - - - (2) INFORMATION FOR SEQ ID NO:3: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2364 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: - - GCCCACACAC CCCACTCCAG CTCCGGAGCA CCCGTGCTGG GCTGCATGGG GA -#CTGGCCGG 60 - - AGGGGCAGGG CCAGGGGAGC GGGTAGGCAG AGCTTCGGGA GGAGATGAGG TG -#AAAGTAAT 120 - - TGACGCTGCC CAGCCCGGCA GTGGGAGAGG CAGGGGATGC GTCAGTGTCG CG -#CTGGAGCT 180 - - GGCAGAGGTG ATGAGCGGCG GAGACACGCG GGGCTGCGAT CGCTCGCCCC AG -#GATGGCCG 240 - - CGGCTCATGG ACCTGTGGCC CCCTCTTCCC CAGAACAGGT GACGCTTCTC CC -#TGTTCAGA 300 - - GATCCTTCTT CCTGCCACCC TTTTCTGGAG CCACTCCCTC TACTTCCCTA GC -#AGAGTCTG 360 - - TCCTCAAAGT CTGGCATGGG GCCTACAACT CTGGTCTCCT TCCCCAACTC AT -#GGCCCAGC 420 - - ACTCCCTAGC CATGGCCCAG AATGGTGCTG TGCCCAGCGA GGCCACCAAG AG -#GGACCAGA 480 - - ACCTCAAACG GGGCAACTGG GGCAACCAGA TCGAGTTTGT ACTGACGAGC GT -#GGGCTATG 540 - - CCGTGGGCCT GGGCAATGTC TGGCGCTTCC CATACCTCTG CTATCGCAAC GG -#GGGAGGCG 600 - - CCTTCATGTT CCCCTACTTC ATCATGCTCA TCTTCTGCGG GATCCCCCTC TT -#CTTCATGG 660 - - AGCTCTCCTT CGGCCAGTTT GCAAGCCAGG GGTGCCTGGG GGTCTGGAGG AT -#CAGCCCCA 720 - - TGTTCAAAGG AGTGGGCTAT GGTATGATGG TGGTGTCCAC CTACATCGGC AT -#CTACTACA 780 - - ATGTGGTCAT CTGCATCGCC TTCTACTACT TCTTCTCGTC CATGACGCAC GT -#GCTGCCCT 840 - - GGGCCTACTG CAATAACCCC TGGAACACGC ATGACTGCGC CGGTGTACTG GA -#CGCCTCCA 900 - - ACCTCACCAA TGGCTCTCGG CCAGCCGCCT TGCCCAGCAA CCTCTCCCAC CT -#GCTCAACC 960 - - ACAGCCTCCA GAGGACCAGC CCCAGCGAGG AGTACTGGAG GCTGTACGTG CT -#GAAGCTGT 1020 - - CAGATGACAT TGGGAACTTT GGGGAGGTGC GGCTGCCCCT CCTTGGCTGC CT -#CGGTGTCT 1080 - - CCTGGTTGGT CGTCTTCCTC TGCCTCATCC GAGGGGTCAA GTCTTCAGGG AA -#AGTGGTGT 1140 - - ACTTCACGGC CACGTTCCCC TACGTGGTGC TGACCATTCT GTTTGTCCGC GG -#AGTGACCC 1200 - - TGGAGGGAGC CTTTGACGGC ATCATGTACT ACCTAACCCC GCAGTGGGAC AA -#GATCCTGG 1260 - - AGGCCAAGGT GTGGGGTGAT GCTGCCTCCC AGATCTTCTA CTCACTGGCG TG -#CGCGTGGG 1320 - - GAGGCCTCAT CACCATGGCT TCCTACAACA AGTTCCACAA TAACTGTTAC CG -#GGACAGTG 1380 - - TCATCATCAG CATCACCAAC TGTGCCACCA GCGTCTATGC TGGCTTCGTC AT -#CTTCTCCA 1440 - - TCCTCGGCTT CATGGCCAAT CACCTGGGCG TGGATGTGTC CCGTGTGGCA GA -#CCACGGCC 1500 - - CTGGCCTGGC CTTCGTGGCT TACCCCGAGG CCCTCACACT ACTTCCCATC TC -#CCCGCTGT 1560 - - GGTCTCTGCT CTTCTTCTTC ATGCTTATCC TGCTGGGGCT GGGCACTCAG TT -#CTGCCTCC 1620 - - TGGAGACGCT GGTCACAGCC ATTGTGGATG AGGTGGGGAA TGAGTGGATC CT -#GCAGAAAA 1680 - - AGACCTATGT GACCTTGGGC GTGGCTGTGG CTGGCTTCCT GCTGGGCATC CC -#CCTCACCA 1740 - - GCCAGGCAGG CATCTATTGG CTGCTGCTGA TGGACAACTA TGCGGCCAGC TT -#CTCCTTGG 1800 - - TGGTCATCTC CTGCATCATG TGTGTGGCCA TCATGTACAT CTACGGGCAC CG -#GAACTACT 1860 - - TCCAGGACAT CCAGATGATG CTGGGATTCC CACCACCCCT CTTCTTTCAG AT -#CTGCTGGC 1920 - - GCTTCGTCTC TCCCGCCATC ATCTTCTTTA TTCTAGTTTT CACTGTGATC CA -#GTACCAGC 1980 - - CGATCACCTA CAACCACTAC CAGTACCCAG GCTGGGCCGT GGCCATTGGC TT -#CCTCATGG 2040 - - CTCTGTCCTC CGTCCTCTGC ATCCCCCTCT ACGCCATGTT CCGGCTCTGC CG -#CACAGACG 2100 - - GGGACACCCT CCTCCAGCGT TTGAAAAATG CCACAAAGCC AAGCAGAGAC TG -#GGGCCCTG 2160 - - CCCTCCTGGA GCACCGGACA GGGCGCTACG CCCCCACCAT AGCCCCCTCT CC -#TGAGGACG 2220 - - GCTTCGAGGT CCAGTCACTG CACCCGGACA AGGCGCAGAT CCCCATTGTG GG -#CAGTAATG 2280 - - GCTCCAGCCG CCTCCAGGAC TCCCGGATAT AGCACAGCTG CCAGGGGAGT GC -#CACCCCAC 2340 - - CCGTGCTCCA CGAGAGACTG TGAG - # - # 2364 - - - - (2) INFORMATION FOR SEQ ID NO:4: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2817 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: double (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4: - - GAATTCGGCA CGAGTCCGAA TCCAAAGGGG TAATGATTTA TCAAACGTGT AT -#TATCAGGA 60 - - AGATGTCAAA CGAAGGGCAC CTTGCTTCCC ACTGACGCAA ACCCGGCCTT TC -#CTGGGGAG 120 - - ATATAGAAAG CGCCTCTTGT TCCAGGGCCA AACCTAGACC AGTAGCGGGG TT -#TTACTCTA 180 - - CGGTTCAATC TGTTGTCCGC ATCAGACATG GATTGCAGTG CTCCCAAGGA AA -#TGAATAAA 240 - - CCACCAACCA ACATCTTGGA GGCAACGGTG CCGGGCCACC GGGATAGCCC TC -#GAGCACCT 300 - - AGGACCAGCC CTGAGCAGGA TCTTCCTGCG GCAGCCCCCG CGGCCGCTGT CC -#AGCCGCCA 360 - - CGTGTGCCCA GGTCGGCTTC CACCGGCGCC CAAACTTTCC AGTCTGCGGA TG -#CGAGAGCC 420 - - TGTGAGGCAC AGCGGCCTGG AGTAGGGTTT TGTAAACTTA GCAGCCCCCA GG -#CACAAGCG 480 - - ACCTCTGCGG CCCTCCGGGA CTTAAGCGAA GGGCACAGCG CACAGGCCAA TC -#CCCCTTCC 540 - - GGGGCCGCTG GGGCTGGCAA CGCTTTACAC TGCAAGATTC CAGCTCTGCG TG -#GCCCGGAG 600 - - GAGGACGAGA ACGTGAGTGT GGCCAAGGGC ACGCTGGAGC ACAACAATAC CC -#CACCCGTG 660 - - GGCTGGGTGA ATATGAGCCA GAGCACAGTG GTGTTGGGTA CCGATGGAAT CG -#CGTCGGTG 720 - - CTCCCGGGCA GCGTGGCCAC CACTACCATT CCGGAGGACG AGCAAGGGGA TG -#AGAATAAG 780 - - GCCAGAGGGA ACTGGTCCAG CAAACTGGAC TTCATCCTGT CCATGGTGGG GT -#ACGCAGTG 840 - - GGGCTGGGTA ATGTTTGGAG GTTTCCCTAC CTGGCCTTCC AGAACGGGGG AG -#GTGCTTTC 900 - - CTCATCCCTT ACTTGATGAT GCTGGCACTG GCTGGCTTAC CTATCTTCTT CC -#TAGAGGTG 960 - - TCCCTGGGCC AGTTTGCCAG CCAGGGTCCT GTGTCTGTGT GGAAGGCCAT CC -#CAGCTCTG 1020 - - CAGGGCTGTG GCATTGCGAT GCTCATCATC TCCGTCCTCA TAGCCATCTA CT -#ACAACGTC 1080 - - ATCATCTGCT ACACGCTCTT CTACCTGTTT GCTTCTTTTG TGTCTGTGCT GC -#CCTGGGGA 1140 - - TCCTGCAACA ACCCGTGGAA CACACCAGAA TGCAAAGACA AAACCAAACT TT -#TACTAGAT 1200 - - TCCTGTGTTA TCGGTGACCA TCCCAAGATA CAGATCAAGA ACTCTACTTT CT -#GCATGACT 1260 - - GCCTATCCGA ACTTGACCAT GGTTAACTTC ACCAGCCAGG CCAATAAGAC AT -#TTGTCAGC 1320 - - GGGAGTGAAG AGTACTTCAA GTACTTTGTG CTGAAGATTT CTGCAGGGAT TG -#AATATCCT 1380 - - GGTGAGATCA GGTGGCCCTT GCCGTTCTGC CTTTTCCTGG CCTGGGTGAT TG -#TATATGCA 1440 - - TCGCTGGCAA AAGGAATTAA GACATCAGGA AAAGTGGTGT ACTTCACAGC CA -#CCTTCCCT 1500 - - TATGTCGTCC TGGTCATCCT CCTCATTCGA GGGGTCACCC TGCCTGGAGC TG -#GAGCCGGT 1560 - - ATCTGGTACT TCATCACACC TAAGTGGGAG AAACTCACGG ATGCCACGGT GT -#GGAAGGAT 1620 - - GCAGCCACTC AGATTTTCTT CTCCCTGTCT GCGGCCTGGG GAGGGCTCAT CA -#CTCTTTCT 1680 - - TCTTACAACA AATTCCATAA CAACTGCTAC AGGGACACGT TAATTGTAAC CT -#GCACCAAC 1740 - - AGTGCCACTA GCATCTTCGC TGGGTTTGTC ATCTTCTCTG TCATTGGCTT CA -#TGGCCAAC 1800 - - GAGCGCAAAG TCAACATTGA GAATGTGGCT GACCAAGGGC CAGGCATTGC AT -#TTGTGGTT 1860 - - TACCCAGAAG CCTTAACCAG GCTGCCTCTC TCTCCATTCT GGGCCATCAT CT -#TTTTCCTG 1920 - - ATGCTTCTCA CGCTTGGACT TGACACCATG TTTGCTACCA TCGAGACCAT TG -#TGACCTCC 1980 - - ATCTCGGATG AGTTTCCCAA GTATCTGCGC ACACACAAGC CTGTGTTCAC CC -#TGGGCTGC 2040 - - TGCATCTGCT TCTTCATTAT GGGCTTCCCA ATGATCACAC AGGGTGGAAT CT -#ACATGTTT 2100 - - CAGCTTGTGG ACACCTATGC TGCCTCCTAT GCTCTTGTCA TCATTGCCAT AT -#TTGAGCTT 2160 - - GTTGGCATCT CCTATGTGTA CGGCTTGCAG AGGTTCTGTG AAGACATCGA GA -#TGATGATT 2220 - - GGATTCCAGC CCAACATTTT CTGGAAGGTC TGCTGGGCGT TTGTCACACC GA -#CCATTTTA 2280 - - ACGTTTATCC TTTGCTTCAG CTTCTATCAG TGGGAGCCCA TGACCTATGG CT -#CCTACCGC 2340 - - TACCCTAACT GGTCCATGGT GCTTGGATGG CTGATGCTCG CCTGCTCCGT GA -#TCTGGATC 2400 - - CCGATTATGT TCGTGATAAA AATGTATCTG GCTCCTGGGA GATTTATTGA GA -#GGCTGAAG 2460 - - TTGGTATGCT CGCCACAGCC GGACTGGGGC CCATTCTTAG CTCAGCACCG CG -#GGGAACGC 2520 - - TACAAGAATA TGATCGACCC CTTGGGAACC TCGTCCCTGG GACTCAAGCT GC -#CAGTGAAG 2580 - - GATTTGGAAC TGGGCACCCA GTGCTAGTCC AGTAGTGTGG ATGGTCCCGT AT -#TAATCCTG 2640 - - GGCTTCCTCT CTGCCTCCCC TCCACACTTT CCCCAGATTT ATTCCCAGTT TT -#CTTCTTTC 2700 - - TCCCCACACC TCGGTTCACA GCTGTGCATG AGAGTGTTCC ATAGAAAAGT AG -#GACCTAAC 2760 - - GTAGCATGCA TTAAATCCAA CTTCCTCTCA CAAAAAAAAA AAAAAAAAAA AA - #AGCTT2817 - - - - (2) INFORMATION FOR SEQ ID NO:5: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 28 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: - - GGGGGAAGCT TATGGATTGC AGTGCTCC - # - # 28 - - - - (2) INFORMATION FOR SEQ ID NO:6: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 29 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: - - GGGGGGGTAC CCAACACCAC TGTGCTCTG - # - # 29 - - - - (2) INFORMATION FOR SEQ ID NO:7: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7: - - CCACATTGTA GTAGATGCCG - # - # - # 20 - - - - (2) INFORMATION FOR SEQ ID NO:8: - - (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base - #pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear - - (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: - - GCAAACTGGC CGAAGGAGAG CTCC - # - # 24__________________________________________________________________________ | The present invention relates to materials and methods for the identification of agents that regulate glycine transport in or out of cells, particularly in or out of neuronal and neuronal-associated cells. Such materials include non-mammalian cells having transfected therein a glycine transporter. The methods relate to the manipulation of such cells such that agents are identified that cause intake or outflow of glycine with respect to a given glycine transporter. | 2 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims foreign priority benefits under 35 USC §119(a)-(d) or §365(b) of Chinese Patent Application No. 200710053034.7, filed Aug. 24, 2007, which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to a process for producing a kaolin product which is especially suitable for paper coating.
BACKGROUND OF THE INVENTION
With the development of modern technique for making paper and the faster speed to coat paper, the requirements for kaolin used in coating paper become stricter. For example, the whiteness should be above 87%; layer structures be maintained; pH value be about 6-7; the particle size distribution (PSD) be as follows: the content of particles of less than 5 μm is 100%, the content of particles of less than 2 μm is 98%, the content of particles of less than 1 μm is more than 90%, and the average particle size is less than 0.5 μm; and the viscosity content is more than 70%. The viscosity contents of the kaolin products produced by the KCS Company of U.S, the Alphacote Company of U.S and the Amazon 88 of Brazil are 70%, 74.5%, and 74.4% respectively. Among these, the kaolin product of KCS for coating paper has a particle size distribution as follows: the content of particles of −3.5 μm is 100%, the content of particles of −2 μm is 99.4%, the content of particles of −0.5 μm is 92.7%; the whiteness is 84.5% and pH value is 7.5. While, in China, the viscosity contents of the kaolin products applied for coating paper are mostly about from 66% to 70% due to the formation of mineral ores and producing technologies (the value of viscosity content are typically used in kaolin industry to measure a concentration, it is specified as a percentage value when the viscosity is 500 mPa·s, and the higher the value, the lower the viscosity). The particle size distribution is not proper and whiteness of kaolin products is emphasized excessively. Hence, China imports a great amount of high quality kaolin products for paper coating from U.S, U.K, Brazil and other countries in the globe every year. The kaolin resources are extremely abundant in China, but most of them can not be applied in the paper coating directly. The problems, within which the viscosity content is the most difficult one to be solved, become the bottle-neck of the production and application of Chinese kaolin and must be addressed urgently.
Kaolin with a minimum formula of Al 4 (Si 4 O 10 )(OH) 8 , is a 1:1 type dioctahedral aluminosilicate comprising a sheet of aluminum atoms coordinated octahedrally with apical oxygen atoms and hydroxyls and another sheet of silicon atoms coordinated tetrahedrally to oxygen, which are coordinated with the same oxygen. One side of the layer structure of kaolin is strong polar hydroxyls and the other side is oxygen atoms. As we know, there are no electrons circling round the hydrionic nucleus and oxygen is a strong electronegative atom, so it is easy to form the hydrogen bond between two sheets, so that kaolin is hardly dispersed.
Rheological behavior of kaolin suspensions has been one of the major factors determining the potential usage of kaolin in the paper industry. Previous studies have indicated three methods to reducing the viscosity of the kaolin slurry.
(1) Mechanical Extrusion
Some researches reduce the viscosity of the kaolin products through changing the particle size, shape and the distribution by milling the kaolin slurry with medium such as zirconia spheres, resin spheres or the like.
China Patent CN1315601A provides a method to reduce the viscosity of the kaolin slurry. The crude ores are purified, and then mixed with water and the clay has a solid content of about 60%-85%; the slurry is placed into an equipment with the functions of kneading and extrusion; the slurry is kneaded and extruded for 10-60 minutes; and then the product is obtained. The viscosity content is improved from 50%-65% of raw ores to more than 68%.
The products treated with that kind of method are affected by the quality of ores greatly and can not eliminate the interferences of the impurities. The limited enhancements confine the application of the methods.
(2) Use of Chemical Additives to Reduce Viscosity
At present, this kind of method is most common and prevailing. Some chemical agents such as sodium silicate, sodium polyacrylate and sodium hexametaphosphate combining with the method to adjust the pH value of slurry are usually used as dispersants to reduce the viscosity and some other new surface active agents are tried also. China patent CN1528979A provides a process to reduce the viscosity and improve the whiteness of the kaolin for paper coating, wherein the slurry is treated by high-gradient magnetic separation, and then chemical bleaching and surface modification. The chemical bleaching is performed under the following conditions: sulfuric acid 1.7-1.9 kg/t, sodium dithionite (also known as sodium hydrosulfite) 6.2-6.6 kg/t, bleaching time 10-20 minutes; sodium polyacrylate (the agent for surface modification) 1.4-1.6 kg/t. This process of that patent mainly emphasizes on how to apply the methods such as the high-gradient magnetic separation and chemical bleaching to improve the whiteness of the kaolin. The reduction of the viscosity of the kaolin products just lies on the chemical agent, sodium polyacrylate, so this method has great limitation. In view of the physical indexes of kaolin products, the viscosity content varies within the great range of 70%-72%. As we know, it is significant on the paper coating even just a variation of about 1%.
The defects of this method is that kaolin ores from different areas require different dispersants to achieve the optimum effect, but there are too many kinds of surface active agents, so it is needed to do plenty of experiments to verify the results. Furthermore, it is difficult to improve the viscosity of the products even at the optimal factors.
(3) Modification of Kaolin Powder
The surface electric property, surface absorption and soakage of kaolin can be changed by physical and chemical methods and the experiments are operated according to the layered structure of kaolin and the properties of structural functional groups of —Si(Al)—OH, —Si—O—Al— and —Si(Al)—O. These kinds of researches are few and generally, the viscosity content of kaolin is reduced by modifying surfaces of kaolin using surface active agents and thus reducing surface energy.
In general, perfect and universally applicable techniques about the viscosity of kaolin have not established until now. Most of researches on the viscosity of kaolin stay at the stage of the theoretical study in addition that the mechanical methods and methods in which dispersants are added are capable of reducing the viscosity of kaolin to some extent.
To control the particle size of kaolin mainly depends on the equipments including mechanical milling besides the hydro cyclones and horizontal spiral classifiers.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a high efficient process for producing a kaolin product for paper coating with high viscosity content and fine particle size.
In order to achieve the above object of the present invention, the process of the present invention comprises the following steps:
(a) mining kaolin ores by hydromechanization and then producing kaolin slurry;
(b) classifying by centrifugal sedimentation, wherein the slurry obtained from the former step is classified with a horizontal spiral sedimentation machine;
(c) chemical bleaching, wherein the kaolin slurry classified by centrifugal sedimentation is bleached;
(d) eliminating iron ions by circular rinsing, wherein the kaolin slurry is washed by circular rinsing and dewatered to remove the ferrous ions and ferric complex and then slurry G is obtained;
(e) removing water by pressure filtration, wherein the kaolin slurry G is filtered under pressure and filter cakes, which contains 32 wt. %-35 wt. % water and have a pH value of 4.3-5.9, fall into a dispersing pond;
(f) producing slurry by deflocculating (filter cakes are treated by chemical agents after they are dewatered), wherein complex dispersants, pH adjusting agent and intercalator are added into the filter cakes; wherein the complex dispersants are sodium hexametaphosphate and sodium polyacrylate, the pH adjusting agent is sodium hydroxide and the intercalator is urea; wherein the sodium polyacrylate has a molecular weight of about 1300-2000, and is added in 1 wt. %-3 wt. % of the dry weight of the filter cakes; the sodium hexametaphosphate is added in 2 wt. %-3 wt. % of the dry weight of the filter cakes; the sodium hydroxide is added in 3 wt. %-4.5 wt. % of the dry weight of the filter cakes; and the urea is added in 2 wt. %-6 wt. % of the dry weight of the filter cakes; and the kaolin slurry is stirred and dispersed to obtain kaolin slurry H whose solid content is 56 wt. %-62 wt. % and pH value is adjusted to 6.3-7.0;
(g) delaminating, wherein the slurry H is added into vertical agitated mills containing a particulate grinding medium, to obtain kaolin slurry I whose solid content is 56 wt. %-62 wt. %;
(h) classifying by vibrating sieve, wherein the kaolin slurry I passes through two layers of 325-mesh vibrating sieves to obtain kaolin slurry J; and
(i) spray drying, wherein spray driers are restructured by adding insulating layers on packing auger, elevator scoop and bunker at first (intercalating urea into the layers of kaolin by the waste heat of the spray drier); wherein the kaolin slurry J which has passed through vibrating sieves is dried in high speed centrifugal spray drying tower, where the parameter of fresh feed pump is 3.5-4.0 Hz, the temperatures of spray drying of the high speed centrifugal spray drying tower (or the temperature of the inlet) and the outlet of the spray drier are set to 230-380° C. and 60-85° C. respectively and the moisture of kaolin powder is controlled in 3 wt. %-5 wt. %; and the intercalation reaction in the kaolin slurry is performed in the process that the powder passes through the packing auger, the elevator scoop and the bunker to obtain the kaolin product for paper coating finally after the intercalation reaction.
The particulate grinding medium is ceramic spheres, glass beads, synthetic corundum spheres or nylonpolyethylene spheres.
In the said step (a), the kaolin ores are mined by hydromechanization and the solid content of slurry is about 6 wt. %-10 wt. %. The sands is removed after the slurry at the mine site pass through the spiral classifier and three-stage hydrocyclones, then kaolin slurry A is obtained and transferred into storage pool. Some dispersants like sodium hexametaphosphate e.g. in 1-2 kg/t and sodium silicate e.g. in 0.8-1.2 kg/t, based on the weight of the kaolin slurry A, are added to the slurry A to obtain kaolin slurry B. The kaolin slurry B goes through the hydrocyclones to obtain kaolin slurry C whose content of sands is reduced to less than 0.05% and the tailings are thrown away. The kaolin slurry C is deposited for a period of time to reach 13 wt. %-19 wt. % to obtain kaolin slurry D.
In said step (b), the kaolin slurry D obtained from the former step is classified with the horizontal spiral sedimentation machine with the rotate speed of 3700-3900 r/min and the separating parameter of 3000-3800. The bottom flow is used for other applications and the overflow is kaolin slurry E.
In said step (c), the kaolin slurry E flows into an octagonal pool and is stirred by an agitator. Sulfuric acid, sodium dithionite (also known as sodium hydrosulfite, Na 2 S 2 O 4 ) and phosphoric acid are added into the kaolin slurry E in the octagonal pool. The addition amount of sulfuric acid, sodium dithionite and phosphoric acid are 2-7 kg/t, 6-8 kg/t and 2-5 kg/t respectively, based on the weight of the kaolin slurry E, and pH value of the kaolin slurry E is adjusted to about 2-4. The kaolin slurry E is bleached for 10-25 minutes and kaolin slurry F is obtained.
The ferric irons (Fe 3+ ) are removed from the kaolin by chemical bleaching with the methods of acid dipping, reduction and complexation. The ferric irons (Fe 3+ ) in the kaolin are reduced to ferrous irons (Fe 2+ ) by sulfuric acid and sodium dithionite under the chemical bleaching reaction (reduction reaction). In order to prevent the reversion that the ferrous irons are re-oxidized to ferric irons and the phenomenon that the slurry is reversed from white to yellow, phosphoric acid is used to complex the ferric ions and the whiteness of the kaolin is improved by washing the complex out from the slurry. The additions of the sulfuric acid and sodium dithionite are determined by the ferric ions content of the kaolin according to the reaction formula. The reaction formula is as follows:
Fe 2 O 3 +Na 2 S 2 O 4 +3H 2 SO 4 ═Na 2 SO 4 +2FeSO 4 +3H 2 O+2SO 2 ↑
The viscosity content of the kaolin product reaches 72%-73.89% and the content of the particles of −2 μm can be improved by 1.1%-4.2%, and the content of particles of −1.5 μm can be improved by about 0.8%-7.5%.
The characteristics of the present invention includes following aspects.
(1) The urea used as an intercalator
The intercalation of kaolin improves the solid content, enhances the efficiency and is beneficial to the delamination of kaolin planer. The products produced by the process of the present invention characterizes in high viscosity content, fine particle size and good effect of granulating.
(2) The time choice of adding the intercalator (urea)
The first reason for the time choice that the urea is added into the dispersing pool is that the addition amount of urea can be metered accurately. The weight of dry kaolin powders of the filter cakes in each pressure filter during the step (f) “producing slurry by deflocculating” is 1 ton (meaning that the weight of the filter cakes in each pressure filter is fixed) and the addition amount of urea is 2%-6% of the weight of the dry powder of the filter cakes, so the metering is very precise. The kaolin exists as flowing slurry during other steps in the whole process and the solid content of the slurry varies usually, so it is not easy to meter the added urea. Furthermore, urea can be added into the dispersing pool with other dispersants and pH adjustor without any other operations such as mechanical fragmentation and urea is resolved after stirred in the pool, so the addition of urea does not affect the next operation. Thirdly, when the filter cakes have been dispersed in the pool, the solid contents of slurry just could be modulated to 51 wt. %-55 wt. % when it is just combined with the dispersants and pH adjustor to assure that the viscosity is in the range of 50-80 mPa·s which is needed at the next step (g) “delaminating”, while in the present invention the solid content of slurry can be modulated to 56 wt. %-62 wt. % to assure that its viscosity is in that range when urea is added into the slurry.
(3) The increase on solid contents of slurry would enhance the effect of delamination in next step. The content of fine particles of −2 μm increases by 1.1 wt. %-4.2 wt. % and the contents of particles of −1.5 μm increases by 0.8 wt. %-7.5 wt. %. Furthermore, the efficiency of the production of kaolin could be improved.
(4) The effect of granulation of kaolin is outstanding and the products are not easy to dust and cause the pollution during the application of it. In the high-speed centrifugal spray drying equipment, the slurry is dried instantaneously under the condition of the heat applied by a furnace. Due to the addition of urea, the effect of granulation of spray-dried powder is outstanding. During the process of the application, the powders with better granulation do not throw dirt; thus do not pollute the working condition and do not impact on the health of workers during the process of powders.
(5) The intercalation reaction is assured by the usage of waste heat of high-speed centrifugal spray drying equipment and water control. In the present invention, the spray drying equipments are reconstituted. The powder goes through the packing auger, the elevator scoop and the bunker from the outlet of the spray drying equipment. The passage provided with temperature, time and water necessary for intercalation of urea. Because the intercalation of urea into kaolin need a certain temperature, the insulating layers on the packing auger, the elevator scoop and the bunker are thicken, so that the waste heat of spray drying, which is sufficient to meet the needs of the temperature of intercalation, is consumed. Furthermore, the reaction of intercalation has requirements for water and reacting time, so water and temperature are necessarily controlled in the spray drying tower and the intercalation reaction time is ensured by delaying the loading time in the present invention.
(6) The viscosity content of the kaolin product for paper coating can be improved from 68%-70% to 72%-73.89% and the performances of the product are stable. The viscosity content of the kaolin produced by the previous technique is just 68%-70%, while that of the kaolin produced by the intercalation achieves 72%-73.89%. This outcomes would not be achieved even the kaolin and urea with the same contents are simply mixed together. The viscosity content of all products in the present invention is more than 72% in the production tests.
(7) The pH value of the products is improved. The pH of the dispersed slurry is modified to 6.3-7.0 in the present invention, so that the pH value of the products are improved from 5.0-6.5 to 6.8-7.4 and the products are very easily dispersed. The pH value of the kaolin produced by the previous technique is 5.0-6.5 and now pH of the products achieves 6.8-7.4. According to the characteristic that kaolin is more easily dispersed in alkaline conditions, we know these kaolin products are more easily dispersed.
(8) The added agents do not affect the coating performance of the products. In the process of coating paper, some urea would be added into the coating colors sometimes in order to improve the properties of the coating colors, so the intercalator (urea) applied does not affect the performance of the colors for paper coating
The advantages of the present invention are in the following aspects. (1) The viscosity content of the kaolin product for paper coating is enhanced from 68%-70% to 72%-73.89% and the performances are stable. (2) The contents of particles of −2 μm and particles of −1.5 μm in the kaolin product for paper coating are improved by 1.1%-4.2%, and by 0.8%-7.5% respectively and the particle size is fine. (3) The pH value of the products is enhanced from 5.0-6.5 to 6.8-7.4, which makes the kaolin disperse more easily. (4) The kaolin has perfect granulation performance and does not throw dust and not contaminate the working conditions when used. (5) During the delaminating in the process, the combination of the technology of intercalation and the method of mechanical milling can improve the efficiency of the delamination of kaolin. The addition of urea can enhance the solid content of the kaolin slurry from 51 wt. %-55 wt. % to 56 wt. %-62 wt. %. (6) The novel addition of urea has no adverse affect on the performances of the paper coated by these kaolin products.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is the flow chart of the process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In order to better comprehend the present invention, the content thereof is further described by way of the following examples. However, the scope of the present invention would not be confined in the following examples. The raw materials used in the following examples are sandy kaolin ores coming from Maoming, Guangdong province, China.
Example 1
As shown in FIG. 1 , a process for producing the kaolin product for paper coating includes the following steps:
(a) The kaolin ores were mined by hydromechanization and the solid content of slurry was 6 wt. %. Kaolin slurry A was obtained when the slurry at the mine site was passed through the spiral classifier and three-stage hydrocyclones to remove the sands, and then the kaolin slurry A was transferred into storage pool. Dispersants sodium hexametaphosphate e.g. in 1 kg/t and sodium silicate e.g. in 0.8 kg/t, based on the weight of the kaolin slurry A, were added to the kaolin slurry A to obtain kaolin slurry B. The kaolin slurry B was passed through the hydrocyclones to obtain kaolin slurry C whose content of sands was reduced to less than 0.05% and the tailings were thrown away. The kaolin slurry C was deposited for a period of time to reach a concentration of 13 wt. % to obtain kaolin slurry D, which was transferred to the next step.
(b) Classifying by centrifugal sedimentation
The kaolin slurry D as transferred from the former step was classified with a horizontal spiral sedimentation machine with the rotate speed of 3700 r/min (round per minute) and the separating parameter of 3000. The bottom flow was used for other applications and the overflow was kaolin slurry E.
(c) Chemical bleaching
The kaolin slurry E was allowed to flow into an octagonal pool and stirred by an agitator. Sulfuric acid, sodium dithionite and phosphoric acid were added into the kaolin slurry E in the octagonal pool. The sulfuric acid, sodium dithionite and phosphoric acid were added in 2 kg/t, 6 kg/t and 2 kg/t respectively, based on the weight of the kaolin slurry E, and pH value of the slurry was adjusted to about 2. The bleaching was performed for 10 minutes, and kaolin slurry F was obtained.
The ferric irons (Fe 3+ ) were removed from the kaolin by chemical bleaching with the methods of acid dipping, reduction and complexation. The ferric irons (Fe 3+ ) in the kaolin were reduced to ferrous irons (Fe 2+ ) by sulfuric acid and sodium dithionite under the chemical bleaching reaction (reduction reaction). In order to prevent the reversion that the ferrous irons are re-oxidized to ferric irons and the phenomenon that the slurry reverses from white to yellow, phosphoric acid was applied to complex the ferric ions and the whiteness of the kaolin was improved by washing the complex out from the slurry. The additions of the sulfuric acid and sodium dithionite were determined by the ferric ions content of the kaolin according to the reaction formula as follows:
Fe 2 O 3 +Na 2 S 2 O 4 +3H 2 SO 4 ═Na 2 SO 4 +2FeSO 4 +3H 2 O+2SO 2 ↑
(d) Iron ions were eliminated by circular rinsing and the kaolin slurry F was washed by circular rinsing and dewatered to remove the ferrous ions and ferric complex and then kaolin slurry G was obtained;
(e) Water was removed by the pressure filtration and the kaolin slurry G was filtered and filter cakes, which contained 32 wt. % water and had a pH value of 4.3, fell into a dispersing pond;
(f) Slurry was produced by deflocculating (the filter cakes were treated by chemical agents after they were dewatered)
Complex dispersants, pH adjusting agent and intercalator were added into the filter cakes. Complex dispersants used were sodium hexametaphosphate and sodium polyacrylate. The pH adjusting agent used was sodium hydroxide and the intercalator was urea. Sodium polyacrylate with a molecular weight of about 1300 was added in 1 wt. %, sodium hexametaphosphate was added in 2 wt. %; sodium hydroxide was added in 3 wt. % and the intercalator urea, a conventional agricultural fertilizer, was added in 2 wt. % as compared to the dry weight of the filter cakes (the weight of the dry powders). The slurry was stirred and dispersed to obtain kaolin slurry H whose solid content was 56 wt. % and pH value was adjusted to 6.3.
(g) Delaminating
The kaolin slurry H was added into vertical agitated mills containing particulate grinding medium (ceramic spheres, glass beads, synthetic corundum spheres or nylonpolyethylene spheres) and then kaolin slurry I was obtained whose solid content was 56 wt. %.
(h) Classifying by vibrating sieve
The kaolin slurry I was passed through two layers of 325-mesh vibrating sieves to achieve kaolin slurry J; and
(i) Spray drying
Spray driers were restructured by adding insulating layers on the packing auger, the elevator scoop and the bunker at first (intercalating urea into the layers of kaolin by the waste heat of the spray drier). The kaolin slurry J which had passed through vibrating sieves was dried in high speed centrifugal spray drying tower, and the parameter of fresh feed pump was 3.5 Hz (in order to control the feed rate), the temperatures of the inlet and the outlet of the spray drier were set to 230° C. and 60° C. respectively and the moisture of kaolin powder was controlled at 3 wt. %. The intercalation reaction in the kaolin slurry was performed in the process that the powder passed through the packing auger, the elevator scoop and the bunker. The kaolin product for paper coating was obtained finally after the intercalation reaction.
The indexes of the products were analyzed (see Table 1 and Table 2).
Example 2
(a) The kaolin ores were mined by hydromechanization and the solid content of slurry was 7 wt. %. Kaolin slurry A was obtained when the slurry at the mine site was passed through the spiral classifier and three-stage hydrocyclones to remove the sands and then kaolin slurry A was transferred into storage pool. Dispersants sodium hexametaphosphate e.g. in 1.5 kg/t and sodium silicate e.g. in 1.0 kg/t, based on the weight of the kaolin slurry A, were added to the kaolin slurry A to obtain kaolin slurry B. The kaolin slurry B was passed through the hydrocyclones to obtain kaolin slurry C whose content of sands was reduced to less than 0.05% and the tailings were thrown away. The kaolin slurry C was deposited for a period of time to reach a concentration of 14 wt. % to obtain kaolin slurry D, which was transferred to the next step.
(b) Classifying by centrifugal sedimentation
The kaolin slurry D as transferred from the former step was classified with a horizontal spiral sedimentation machine with the rotate speed of 3800 r/min and the separating parameter of 3200. The bottom flow was used for other applications and the overflow was kaolin slurry E.
(c) Chemical bleaching
The kaolin slurry E was allowed to flow into an octagonal pool and stirred by an agitator. Sulfuric acid, sodium dithionite and phosphoric acid were added into the slurry E in the octagonal pool. The sulfuric acid, sodium dithionite and phosphoric acid were added in 3.5 kg/t, 6 kg/t and 2.3 kg/t respectively, based on the weight of the kaolin slurry E, and pH value of the slurry was adjusted to about 3. The bleaching was performed for 15 minutes, and kaolin slurry F was obtained.
(d) Iron ions were eliminated by circular rinsing and the kaolin slurry F was washed by circular rinsing and dewatered to remove the ferrous ions and ferric complex and then kaolin slurry G was obtained.
(e) Water was removed by the pressure filtration and the kaolin slurry G was filtered and filter cakes, which contained 33 wt. % water and had a pH value of 5.0, fell into a dispersing pond.
(f) Slurry was produced by deflocculating (the filter cakes were treated by chemical agents after they were dewatered)
Complex dispersants, pH adjusting agent and intercalator were added into the filter cakes. Complex dispersants used were sodium hexametaphosphate and sodium polyacrylate. The pH adjusting agent used was sodium hydroxide and the intercalator was urea. Sodium polyacrylate with a molecular weight of about 1500 was added in 1 wt. %, sodium hexametaphosphate was added in 2.5 wt. %; sodium hydroxide was added in 3 wt. % and the intercalator urea, a conventional agricultural fertilizer, was added in 2 wt. % as compared to the dry weight of the filter cakes (the weight of the dry powders). The slurry was stirred and dispersed to obtain kaolin slurry H whose solid content was 58 wt. % and pH value was adjusted to 6.5.
(g) Delaminating,
The kaolin slurry H was added into vertical agitated mills containing a particulate grinding medium (ceramic spheres, glass beads, synthetic corundum spheres or nylonpolyethylene spheres) and then kaolin slurry I was obtained whose solid content was 56 wt. %.
(h) Classifying by vibrating sieve
The kaolin slurry I was passed through two layers of 325-mesh vibrating sieves to achieve kaolin slurry J.
(i) Spay drying
Spray driers were restructured by adding insulating layers on the packing auger, the elevator scoop and the bunker at first (intercalating urea into the layers of kaolin by the waste heat of the spray drier). The kaolin slurry J which had passed through vibrating sieves was dried in high speed centrifugal spray drying tower, and the parameter of fresh feed pump was 3.8 Hz, the temperatures of the inlet and the outlet of the spray drier were set to 258° C. and 65° C. respectively and the moisture of kaolin powder was controlled at 4 wt. %. The intercalation reaction in the kaolin slurry performs was performed in the process that the powder passed through the packing auger, the elevator scoop and the bunker. The kaolin product for paper coating was obtained finally after the intercalation reaction.
The indexes of the product were analyzed (see Table 1 and Table 2).
Example 3
The process for producing the kaolin product for paper coating included the following steps:
(a) The kaolin ores were mined by hydromechanization and the solid content of slurry was 7 wt. %. Kaolin slurry A was obtained when the slurry at the mine site was passed through the spiral classifier and three-stage hydrocyclones to remove the sands and then the kaolin slurry A was transferred into storage pool. Dispersants sodium hexametaphosphate e.g. in 1.5 kg/t and sodium silicate e.g. in 1.02 kg/t, based on the weight of the kaolin slurry A were added to the kaolin slurry A to obtain kaolin slurry B. The kaolin slurry B was passed through the hydrocyclones to obtain kaolin slurry C whose content of sands was reduced to less than 0.05% and the tailings were thrown away. The kaolin slurry C was deposited for a period of time to reach a concentration of 15 wt. % to obtain kaolin slurry D, which was transferred to the next step.
(b) Classifying by centrifugal sedimentation
The kaolin slurry D as transferred from the former step was classified with a horizontal spiral sedimentation machine with the rotate speed of 3800 r/min and the separating parameter of 3500. The bottom flow was used for other applications and the overflow was kaolin slurry E.
(c) Chemical bleaching
The kaolin slurry E was allowed to flow into an octagonal pool and stirred by an agitator. Sulfuric acid, sodium dithionite and phosphoric acid were added into the kaolin slurry E in the octagonal pool. The sulfuric acid, sodium dithionite and phosphorous acid were added in 5 kg/t, 7 kg/t and 3.4 kg/t respectively, based on the weight of the kaolin slurry E, and pH value of the kaolin slurry was adjusted to about 3. The bleaching was performed for 15 minutes, and kaolin slurry F was obtained.
(d) Iron ions were eliminated by circular rinsing and the kaolin slurry F was washed by circular rinsing and dewatered to remove the ferrous ions and ferric complex and then kaolin slurry G was obtained.
(e) Water was removed by the pressure filtration and the kaolin slurry G was filtered and filter cakes, which contained 33 wt. % water and pH value was 5.0, fell into a dispersing pond.
(f) Slurry was produced by deflocculating (the filter cakes were treated by chemical agents after they were dewatered)
Complex dispersants, pH adjusting agent and intercalator were added into the filter cakes. Complex dispersants used were sodium hexametaphosphate and sodium polyacrylate. The pH adjusting agent used was sodium hydroxide and the intercalator was urea. Sodium polyacrylate with a molecular weight of about 1500 was added in 1 wt. %, sodium hexametaphosphate was added in 2.5 wt. %; sodium hydroxide was added in 3 wt. % and the intercalator urea, a conventional agricultural fertilizer, was added in 5 wt. % as compared to the dry weight of the filter cakes (the weight of the dry powders). The slurry was stirred and dispersed to obtain kaolin slurry H whose solid content was 59 wt. % and pH value was adjusted to 6.5.
(g) Delaminating
The kaolin slurry H was added into vertical agitated mills containing a particulate grinding medium (ceramic spheres, glass beads, synthetic corundum spheres or nylonpolyethylene spheres) and then kaolin slurry I was obtained whose solid content was 56 wt. %.
(h) Classifying by vibrating sieve
The kaolin slurry I was passed through two layers of 325-mesh vibrating sieves to achieve kaolin slurry J.
(i) Spay drying
Spray driers were restructured by adding insulating layers on the packing auger, the elevator scoop and the bunker at first (intercalating urea into the layers of kaolin by the waste heat of the spray drier). The kaolin slurry J which had passed through vibrating sieves was dried in high speed centrifugal spray drying tower, and the parameter of fresh feed pump was 3.8 Hz, the temperatures of the inlet and the outlet of the spray drier were set to 370° C. and 70° C. respectively and the moisture of kaolin powder was controlled at 5 wt. %. The intercalation reaction in the kaolin slurry was performed in the process that the powder passed through the packing auger, the elevator scoop and the bunker. The kaolin product for paper coating was obtained finally after the intercalation reaction.
The indexes of the product were analyzed (see Table 1 and Table 2).
Example 4
The process for producing the kaolin product for paper coating included the following steps:
(a) The kaolin ores were mined by hydromechanization and the solid content of slurry was 10 wt. %. Kaolin slurry A was obtained when the slurry at the mine site was passed through the spiral classifier and three-stage hydrocyclones to remove the sands and then the kaolin slurry A was transferred into storage pool. Dispersants sodium hexametaphosphate e.g. in 2 kg/t and sodium silicate e.g. in 1.2 kg/t, based on the weight of the kaolin slurry A, were added to the kaolin slurry A to obtain kaolin slurry B. The kaolin slurry B was passed through the hydrocyclones to obtain kaolin slurry C whose content of sands was reduced to less than 0.05% and the tailings were thrown away. The kaolin slurry C was deposited for a period of time to reach a concentration of 19 wt. % to obtain kaolin slurry D.
(b) Classifying by centrifugal sedimentation
The kaolin slurry D as transferred from the former step was classified with a horizontal spiral sedimentation machine with the rotate speed of 3900 r/min and the separating parameter of 3800. The bottom flow was used for other applications and the overflow was kaolin slurry E.
(c) Chemical bleaching
The kaolin slurry E was allowed to flow into an octagonal pool and stirred by an agitator. Sulfuric acid, sodium dithionite and phosphoric acid were added into the slurry E in the octagonal pool. The sulfuric acid, sodium dithionite and phosphorous acid were added in 7 kg/t, 8 kg/t and 5 kg/t respectively, based on the weight of the kaolin slurry E, and pH value of the slurry was adjusted to about 4. The bleaching was performed for 25 minutes, and kaolin slurry F was obtained.
(d) Iron ions were eliminated by circular rinsing and the kaolin slurry F was washed by circular rinsing and dewatered to remove the ferrous ions and ferric complex and then kaolin slurry G was obtained.
(e) Water was removed by the pressure filtration and the kaolin slurry G was filtered and filter cakes, which contained 35 wt. % water and pH value was 5.9, fell into a dispersing pond.
(f) Slurry was produced by deflocculating (the filter cakes were treated by chemical agents after they were dewatered)
Complex dispersants, pH adjusting agent and intercalator were added into the filter cakes. Complex dispersants used were sodium hexametaphosphate and sodium polyacrylate. The pH adjusting agent used was sodium hydroxide and the intercalator was urea. Sodium polyacrylate with a molecular weight of about 2000 was added in 3 wt. %, sodium hexametaphosphate was added in 3 wt. %; sodium hydroxide was added in 4.5 wt. % and the intercalator urea, a conventional agricultural fertilizer, was added in 6 wt. % as compared to the dry weight of the filter cakes (the weight of the dry powders). The slurry was stirred and dispersed to obtain kaolin slurry H whose solid content was 62 wt. % and pH value was adjusted to 6.5.
(g) Delaminating
The kaolin slurry H was added into vertical agitated mills containing a particulate grinding medium (ceramic spheres, glass beads, synthetic corundum spheres or nylonpolyethylene spheres and then kaolin slurry I was obtained whose solid content was 62 wt. %.
(h) Classifying by vibrating sieve
The slurry I was passed through two layers of 325-mesh vibrating sieves to achieve kaolin slurry J.
(i) Spay drying
Spray driers were restructured by adding insulating layers on the packing auger, the elevator scoop and the bunker at first (intercalating urea into the layers of kaolin by the waste heat of the spray drier). The kaolin slurry J which had passed through vibrating sieves was dried in high speed centrifugal spray drying tower, and the parameter of fresh feed pump was 4.0 Hz, the temperatures of the inlet and the outlet of the spray drier were set to 380° C. and 85° C. respectively and the moisture of kaolin powder was controlled at 5 wt. %. The intercalation reaction in the kaolin slurry was performed intercalation reaction in the process that the powder passed through the packing auger, the elevator scoop and the bunker. The kaolin product for paper coating was obtained finally after the intercalation reaction.
The indexes of the products were analyzed (see Table 1 and Table 2).
TABLE 1
The analysis of indexes of the products
The content of
Sample
particles of
Sand (mesh
pH
Viscosity
number
Whiteness/%
−2 μm/%
Moisture/%
residue)/%
value
content/%
Products
87
94.8
1.3
0.003
6.34
69
produced by
traditional
technique
Example 1
86.6
96.5
3.4
0.005
7.01
73.3
Example 2
86.5
95.9
4.8
0.005
7.40
72.33
Example 3
86.8
99.0
1.8
0.006
7.18
72.99
Example 4
86
96.0
4.4
0.005
7.13
73.89
TABLE 2
Particle size distribution of the products(particle size, μm; content, %)
Sample number
5.000
4.250
3.500
3.000
2.500
2.000
1.500
1.000
0.500
Prod-
100.0
100.0
99.9
99.5
97.9
94.8
90.2
81.8
81.8
ucts by
tradi-
tional
tech-
nique
Exam-
100.0
99.8
98.8
96.5
91.6
83.4
83.4
ple 1
Exam-
100.0
99.7
98.1
95.9
91.0
80.8
80.8
ple 2
Exam-
100.0
99.7
99.0
97.7
95.9
95.9
ple 3
Exam-
100.0
99.8
98.5
96.0
91.8
83.5
83.2
ple 4 | A process of producing a kaolin product for paper coating includes mining kaolin ores by hydromechanization and then producing kaolin slurry; classifying by centrifugal sedimentation; chemical bleaching; eliminating iron ions by circular rinsing; removing water by pressure filtration; producing slurry by dispersing filter cakes, in which complex dispersants, pH adjustor and intercalator are added; delaminating; classifying by vibrating sieve; and spray drying: spray driers are restructured by adding insulating layers on packing auger, elevator scoop and bunker at first; the kaolin slurry J which has passed through vibrating sieves is dried in high speed centrifugal spray drying tower and the moisture of kaolin powder is controlled in 3 wt. %-5 wt. %, and the kaolin product for paper coating is obtained. The process characterizes in stable properties, high efficiency, and high viscosity content and fine particle size of the kaolin products produced. | 2 |
This is a division of application Ser. No. 519,883 filed Oct. 31, 1974, and now U.S. Pat. No. 3,953,637.
BACKGROUND OF THE INVENTION
The present invention relates to a process for forming fiber reinforced rods and more particularly relates to a method for making high modulus, high strength, low density slender tapered solid composite rods suitable for use as fishing rods and the like.
Typically, present day high quality fiber glass fly rods are hollow and are constructed by wrapping a resin-impregnated fiber glass cloth over a tapered, removable steel mandrel. After oven curing, the mandrels are removed preparatory to rod finishing. This type of hollow construction is employed in order to reduce rod weight while maintaining appropriate section stiffness. As a result however, the rod diameter is relatively large and tip windage losses during casting are significant.
With the advent of newer, high specific modulus fibers such as boron and graphite, the concept of a cross-sectionally solid rod having acceptable section stiffness without an appreciable weight penalty is feasible. Such a rod would possess both minimum tip windage losses as well as maximum structural integrity against lateral loading.
Although the potential advantages of modern day materials is thus recognized, the problems apparent in utilizing them have remained for solution. While rod construction via tape lay-up may be accomplished in several ways, significant problems arise in the curing of a solid composite green rod since, during this time, it is difficult to restrain the filaments from wandering. The end result can be the occurrence of nonconcentric rod ends, local bulging and/or warping. While it may be speculated that matched dye molding or tapered tube molding would likely solve all of these problems, the large expense due to large L/D ratios, the compound tapers employed in most rods and the large number of different models usually manufactured, renders this technique unattractive.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide a method for making a high modulus, high strength, low density slender tapered solid composite rod suitable for use in fishing rods or the like which overcomes the problems outlined above.
In accordance with one aspect of the invention, a method for making a solid, tapered fiber-reinforced resin matrix composite rod having a high aspect ratio comprises forming a plurality of resin-impregnated fibers into a handlable, green compact having the shape of a solid tapered composite rod of high aspect ratio, completely encasing said green compact within an embracing molding surface, placing said encased green compact within a rigid tube in spaced relation to the walls thereof, filling the space between said enclosed compact and said tube with particulate material to apply uniform contact pressure along the length of said compact, and heating said rod to harden said resin. Aspect ratio, as applied to rods tapered throughout their length such as those described herein, means the L/D ratio, i.e., the ratio of the length of the rod to the smaller diameter thereof. For the purposes of the present invention the term "high aspect ratio" means an aspect ratio wherein L/D ranges from approximately 400-4,000.
In accordance with a preferred mode of carrying out the present invention, the process comprises the steps of applying a resin to a plurality of high modulus, high strength, low density filaments, disposing said filaments uniformly about and in parallel relationship to a wire mandrel to form a green composite rod, said filaments being less in number at one end of the wire than at the other end, compacting said green rod to densify and shape it to a preselected configuration, completely encasing said green rod within an embracing molding surface, placing said encased green rod within a rigid tube in spaced relation to the walls thereof, filling the space between said enclosed rod and said tube with particulate material in order to apply a uniform peripheral contact pressure along the length of said rod sufficient to laterally restrain the rod during resin cure and ensure alignment of the filaments, and heating said rod to harden the resin. After the green composite rod is heated, it is taken from the tube and the embracing molding surface is removed.
In one aspect of the invention, the embracing molding surface comprises a first cap snugly fitted over one end of the green rod, a second cap snugly fitted over the other end of the green rod and a binding tape wound over the entire surface of the green rod between the first and second end caps. In accordance with another aspect of the invention, the rigid tube is preferably vertically oriented, the filaments are selected from the group consisting of boron, carbon and polymeric aromatic nylon. In a more preferred embodiment of the inventive process, resin impregnated boron filaments are disposed uniformly about and in parallel relationship to the metal wire with said boron filaments being less in number at one end of the wire than at the other end and a plurality of resin impregnated carbon fibers are disposed as an outer layer on the boron filaments.
The instant invention is further concerned with the slender tapered product producible by the inventive process. In particular, the invention contemplates a solid, tapered composite rod having a tip size as small as 1/32 inch for fishing rods and the like comprising a wire core, preferably metal, extending the length of the rod, a plurality of boron filaments uniformly disposed about the wire and in parallel relation thereto, the boron filaments being less in number at one end of the wire than at the other end, and a plurality of carbon fibers uniformly disposed as an outer layer about the plurality of boron filaments and in parallel relation thereto, the wire, boron filaments and carbon fibers being embedded in and bonded to a cured resin matrix.
BRIEF DESCRIPTION OF THE DRAWINGS
An understanding of the invention will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings, wherein:
FIG. 1 is a side elevational view of apparatus useful in laying up the composite rod of the present invention;
FIG. 2 is a sectional view taken on line 2--2 of FIG. 1;
FIG. 3 is an end view of the composite rod after lay-up in the apparatus shown in FIG. 1;
FIG. 3a is an enlarged end view of a portion of FIG. 3;
FIG. 4 is an end view of the rod of FIG. 3 after rolling; and
FIG. 5 is a side elevational view, in section, of molding apparatus used with the composite rod during heating.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2 there is shown an elongated form 10 having an axial channel 12 therein. At the base of the channel 12, there is provided a centrally located and axially extending guide slot 14 which runs the length of the form 10. A wire 16, preferably a metal wire such as a steel wire 0.010-0.020 inch in diameter, is laid in the guide slot 14 and loaded in tension by securing one end to a stationary object such as hook 18 and hanging a small weight 20, typically 1 to 2 pounds, to its other end. Other wire materials, so long as they are compatible with and adhere to the resin matrix material used, are of small diameters such as 0.010-0.020 inch, may be kept straight by tensile loading and are strong enough to withstand the production process techniques herein described, may also be used. Typical examples are copper wire, graphite yarn and cotton or silk filaments. In order to employ the wire 16 as a permanent mandrel from the outset as will hereinafter becomes clear, the guide slot has a depth which corresponds to approximately one-half the diameter of the wire 16. With the wire 16 positioned in the slot 14, a plurality of resin-impregnated high strength, high modulus, low density filaments 22 preferably in the form of a prepreg monolayer tape strip 24 are laid over the wire 16.
Filaments (or fibers -- the two terms being used interchangeably herein) considered suitable are high modulus, high strength, low density filaments, i.e., those having an elastic modulus significantly greater than that of fiber glass but with similar or better strength and density. In particular, filaments which are preferred are those having an elastic modulus of at least approximately 15 million psi, a flexural strength of at least approximately 300,000 psi and a density no greater than approximately 0.15 lb/in 3 , e.g., boron filaments, coated or uncoated, carbon or graphite fibers or filaments, silicon carbide filaments and organic filaments such as polymeric aromatic nylon sold by duPont under the trademark KEVLAR PRD 49. Most preferred are filaments of boron, carbon and KEVLAR PRD 49. The filaments, as indicated, are preferably in the form of a tacky prepreg tape, such as a boron-epoxy resin prepreg monolayer tape, typically one utilizing a plurality (e.g., 10) of 4 or 5.6 mil unidirectional boron filaments. The width of the tape utilized depends, of course, on the diameter of the rod section being fabricated. In general however, tapes ranging in widths from 1/16 to 1/8 inch are considered satisfactory for most fishing rod applications. It will be recognized, of course, that individual filaments may also be utilized, either precoated with resin or with the resin applied after filament emplacement.
Various heat curable resin compositions may be utilized as the filament matrix material. Resins considered useful are the epoxy resins including polyglydicyl ethers of polyhydric phenols and cycloaliphatic epoxy resins as well as cresol novolac epoxy resins.
With the tape strip 24 laid in the bottom of channel 12 over wire 16, it is secured in position by clamping one end thereof by suitable means such as thumb clamp 28. The tape is then compacted and forced into intimate contact with the aforesaid wire 16 by rolling a compaction roller 26 the length of the channel 12. Although a compaction plate may be utilized in lieu of the compaction roller, the latter is preferred because of the extremely high local pressure which can be obtained therewith and because of the tendency of the rolling action to straighten adjacent fibers. After the first strip has been rolled, the wire 16 and the strip are peeled from the form 10 and turned over so that a second strip 24 may be placed on the exposed side of the wire 16 and compacted. Additional tape strips 24 are successively laid up on the previous strip, clamped and compacted with the roller 26. After the desired number of tape strips are thus assembled, the composite assembly is turned over once more and the requisite and equal number of tape layers are laid up, clamped and compacted on the other side. As will be appreciated, it is during the lay-up procedure that the taper is built into the rod. Typically some or all filaments are eliminated fron an end portion of a sequence of tape strips by trimming the end portion to a desired shape (e.g., diagonal, sawtooth) and/or length.
As an alternate technique, since at times the wire 16 may possess some twist and thus be difficult to retain in the slot 14 prior to laying up the initial tape strip 24, the strip may be laid in the bottom of channel 12 before the wire, with the wire then emplaced thereon. Also suitable is the technique wherein, prior to emplacing the wire 16 into the form 10, the wire is weighted and hung vertically and initial strips 24 are laid on opposite sides thereover.
The intermediate product resulting from the afore-described technique is green composite rod 30 as shown in FIG. 3. As will be noted, the product while being highly densified and having sufficient structural integrity for handling purposes, is rectangular in cross section. In order to achieve the typical and desired circular cross section, it is thus necessary to remove the rod 30 from the form 10 and roll it to the desired circular shape 32 as shown in FIG. 4. This may be done by manipulation between the thumb and forefinger of the hand or by rolling between opposed oscillating plates or by other suitable techniques.
After rounding to a circular cross section, additional successively shorter tape layers may be wrapped around the rod to continue the taper toward the large diameter end of the rod. Each tape layer has a width which is equal to the circumference of the underlying rod surface to assure complete coverage without overlap. In general, the tape layers are sawtoothed at their tip ends with successive layers being progressively shorter. The materials making up the initial tape layers are the same as used in the tape strips 24. As will be appreciated, the tape layers are applied to the rod with their filaments parallel to the rod axis. Although it is suitable to use only one type of high modulus, high strength, low density filament for making the entire rod, such as the boron filaments described, it is preferred to provide as the outermost layer a prepreg tape reinforced with lower modulus fibers, e.g., a graphite-epoxy prepreg tape. The final layer or layers are trapezoidal in shape and comprise tapes of resin reinforced with high modulus, high strength, low density filaments which have a strength approximately the same or higher than the boron filaments but which have an elastic modulus which is appreciably lower. Suitable as filaments in the final layers are graphite and KEVLAR. Having graphite or KEVLAR filaments in the surface layer results in a more attractive product from an aesthetic viewpoint and one which can be made extremely smooth as by sanding. In addition, and perhaps more importantly, having graphite or KEVLAR filaments in the outer layer increases the flexural stress margin of safety since, as compared to boron, the graphite or KEVLAR filaments can better withstand high flexural loading because of their somewhat lower elastic modulus.
Having observed the details of initial fabrication, attention may now be given to the curing of the resin matrix material. As will be appreciated, during curing, the matrix resin between the filaments flows and the filaments, particularly those in the ends of the rod 32 have a tendency to wander. Although reasonable straightness can be achieved in curing by simply helically wrapping the green rod 32 with nonadherent tape strips over its entire length and then applying tension to the wire while the rod is curing in a vertical position, problems have been found to persist with this procedure. It has been found, for example, that during curing the rod ends have tended to lose concentricity with the wire 16. In addition, local rod warping has occurred, probably caused by uneven resin expansion and/or contraction during curing. Further, with significant wire tension, overall tip warping can result from relaxation of the wire mandrel after curing. Finally the utilization of this technique with relatively thick rod sections, has manifested a tendency for local lateral bulging to occur, probably due to entrapped air or water vapor.
In order to overcome these problems, it has been found necessary to completely encase the green rod within an embracing molding surface in such a manner so as to provide increased lateral and end support. As shown in FIG. 5, the ends of the rod 32 are snugly fitted within mold end caps 34, preferably of a material such as Teflon which will withstand cure temperatures without bonding to the rod. Each of the end caps 34 has a central axial opening 36 to accommodate the wire 16. Between the caps, the rod surface is completely wound with a binding tape 38, preferably of a material such as Teflon tape or cellophane ribbon or the like which will also withstand cure temperatures without bonding to the rod. In practice, in order to minimize resin leakage, it has been found advantageous to helically wrap first with Teflon tape and then, in the opposite helical direction, with cellophane type shrink tape.
The green rod, being totally encased in binding tape 38 and mold end caps 34, is positioned within a rigid hollow tube 40. It can be seen that if the entire assembly is oriented vertically and if the wire 16 is loaded in tension, the rod is concentric within the tube 40 and has its wound surface 38 in spaced relation to the inner walls thereof, the end caps acting as spacers for this purpose. The tube 40 is provided with a series of circumferentially spaced apertures 42 at its upper end which are located below the end walls of the upper cap 34. A filler cap 44 is slidably disposed on the upper end of the tube 40 to provide ingress into the tube through the apertures 42 of particulate material 46, such as glass beads or sand. The particulate material is relatively fine-grained for maximum lateral contact surface and provides a uniform contact pressue about the periphery of the rod throughout the contacted length as well as the lateral restraint needed to ensure alignment of the filaments during and after curing. In addition, its natural porosity permits the release of entrapped air or water vapor and will also act as a wick should any excess resin bleed from between the binding tape layers. Glass beads or similar spherical particulates are preferred over sand since the latter, although useful, comprise jagged-edged particles which do not compact as well as the smooth glass beads.
In operation, the wire 16 is threaded through the opening 36 in end caps 34 so that the end caps may be positioned over the ends of the composite rod. With the end caps in place, the binding tape 38 is applied over the entire surface of the intermediate portion of the rod between the aforesaid end caps. The encased rod is then positioned, by sliding, within the tube 40. An end plate 48 having an opening 50 through which the wire 16 is threaded, is secured upwardly against the bottom of the tube 40 by crimp cap 52, the upper looped end of wire 16 being supported, as by a hook from above and tensioned, as by a weight from below. While the weight of the tube and particulate material may provide sufficient tension to the wire, it is preferred to add more weight to eliminate any risk of movement during addition. With the filler cap 44 in place on the vertically oriented tube, the particulate material 46 is supplied therethrough to apertures 42 and thence to tube 40. Once the tube 40 is completely filled, the filler cap is removed, the apertures 42 are sealed with a high temperature adhesive tape and tension in the wire may be reduced or removed in order to eliminate the possibility of warping after cure due to residual stress in the wire. The entire assemblage which is now unitary and easy to handle is emplaced within an oven where the cure cycle satisfactory for the particular resin utilized, (typically: heat to 350° F in 15 minutes; hold for 2 hours) is accomplished. After curing, the encased rod is removed from the tube 40, the end caps are taken off and the binding tape 38 is unwrapped.
A plurality of slender, tapered solid composite rods (fly rod butt sections) ranging in length from 36 to 48 inches were made according to the invention. A typical butt section was 45 inches long and tapered from 5/32 inch diameter up to 7/32 inch diameter utilizing a 14-16 mil diameter soft annealed steel wire core. Boron-epoxy prepreg tapes 5/64 inch wide (containing approximately eleven 5.6 mil boron filaments) were used for the lay-up in the form 10. After removal from the form and rounding, several layers of additional monolayer boron-epoxy tape were wrapped around the rod. Finally, one layer of trapezoidally shaped monolayer graphite-epoxy tape was wrapped therearound. The cured rods were straight with filaments uniformly distributed about the wire mandrel throughout their length. A like number of tip sections of equal length as the butt sections above described were made using the same techniques. The tip sections tapered from 3/64 inch up to 5/32 inch.
What has been set forth above is intended primarily as exemplary to enable those skilled in the art in the practice of the invention and it should therefore be understood that, within the scope of the appended claims, the invention may be practiced in other ways than as specifically described. | There is described a method for forming high modulus, high strength, low density solid tapered composite rods suitable for use as fishing rods and the like. The method comprises the steps of disposing a plurality of resin-impregnated high modulus, high strength, low density fibers such as boron, carbon, polymeric aromatic nylon or the like uniformly about and in parallel relation to a wire mandrel, the fibers being less in number at one end than at the other end to form a green composite tapered rod, compacting the rod to densify and shape it to a preselected configuration, completely encasing the rod within an embracing molding surface, placing the encased green rod within a rigid tube in spaced relation to the walls thereof, filling the space between the enclosed rod and the tube with particulate material to apply uniform peripheral contact pressure along the length of the rod sufficient to laterally restrain the rod during resin cure and thereby ensure alignment of the fibers and heating the rod to cure the resin. | 0 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The instant application claims priority to U.S. Provisional Patent Application Ser. No. 60/474,774, filed May 30, 2003, the entire specification of which is expressly incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to solenoid control valves, and more particularly to a pulse width modulated solenoid control valve for controlling hydraulic functions of a transmission for a vehicle.
BACKGROUND OF THE INVENTION
[0003] Various solenoid designs have been used in the automotive industry, including those for use in conjunction with automatic transmission systems. For example, automatic transmission control systems generally employ solenoids in order to control the pressure and flow of the transmission fluid. In this manner, the control of transmission fluid pressure can be used to engage and disengage a transmission clutch in response to an electrical input signal supplied to the solenoid, or the control of transmission fluid pressure can be used to maintain transmission line pressure.
[0004] Generally, solenoids employ a solenoid control valve to aid in the regulation of the fluid flow by the solenoid. An example of a solenoid control valve can be found in U.S. Pat. No. 4,998,559 to McAuliffe et al., the entire specification of which is incorporated herein by reference. Recently, the use of pulse width modulated solenoids has become more prevalent in certain automotive applications.
[0005] Although pulse width modulated conventional solenoid control valves have been somewhat successful in meeting the demands of the automotive industry, these pulse width modulated solenoid control valves can be further improved upon, e.g., in the areas of cost, quality, performance, and the like.
[0006] Accordingly, there exists a need for new and improved pulse width modulated solenoid control valves.
SUMMARY OF THE INVENTION
[0007] A new and improved solenoid control valve is provided, in accordance with the general teachings of the present invention. More specifically, a new and improved pulse width modulated solenoid control valve is provided, in accordance with one embodiment of the present invention
[0008] The solenoid control valve preferably employs a plastic control valve body that preferably includes a segmented flow path that adds strength to the supply tube portion. In accordance with a preferred embodiment of the present invention, a stepped coil portion is preferably provided. In accordance with another preferred embodiment of the present invention, an actuation rod is preferably provided that is tapered adjacent to and contacting the armature so as to reduce flux shorting and improve operating characteristics. Accordingly, the solenoid control valve of the present invention preferably provides a characteristic performance curve.
[0009] In accordance with a first embodiment of the present invention, a solenoid fluid control valve is provided, comprising: (1) a fluid control body adapted for being received in a fluid housing, said fluid control body including a central cavity, and having a pressure supply passage at a first end and a radially extending pressure control passage; (2) a feed supply tube positioned in said central cavity, said feed supply tube including an outer diameter in communication with the pressure control passage, and including an inner bore operably connected to said pressure supply passage, said feed supply tube being supported in said central cavity of said fluid control body by way of a radially and axially extending wall, said wall being segmented into a plurality of longitudinally extending flow chambers, said feed supply tube including a valve receiving chamber area; (3) a valve seat portion being made of a metallic material and press fit into said fluid control body, said valve seat portion including a valve seat and a passage in communication between said valve seat and said pressure control passage; (4) a valve contained in said valve receiving chamber operable to selectively close off communication between said pressure supply passage and said pressure control passage; and (5) a solenoid for opening said valve in response to a signal.
[0010] In accordance with a second embodiment of the present invention, a solenoid fluid control valve is provided, comprising: (1) a fluid control body adapted for being received in a fluid housing, said fluid control body including a central cavity, and having a pressure supply passage at a first end and a radially extending pressure control passage; (2) a feed supply tube positioned in said central cavity, said feed supply tube including an outer diameter in communication with the pressure control passage, and including an inner bore operably connected to said pressure supply passage, said feed supply tube being supported in said central cavity of said fluid control body by way of a radially and axially extending wall, said wall being segmented into a plurality of longitudinally extending flow chambers, said feed supply tube including a valve receiving chamber area; (3) a valve seat portion being made of a metallic material and press fit into said fluid control body, said valve seat portion including a valve seat and a passage in communication between said valve seat and said pressure control passage; (4) a valve contained in said valve receiving chamber operable to selectively close off communication between said pressure supply passage and said pressure control passage; (5) a solenoid for opening said valve in response to a signal, wherein said solenoid includes a central axis and has a coil wound around a bobbin, spaced from and positioned around said central axis, said coil having radially stepped radial inner diameters; (6) a casing member for attaching said solenoid to said fluid control body; a portion of said casing member extending into the stepped portion of said coil for forming a flux tube therein; and (7) an armature axially movable within said bobbin.
[0011] In accordance with a third embodiment of the present invention, a solenoid fluid control valve is provided, comprising: (1) a fluid control body adapted for being received in a fluid housing, said fluid control body including a central cavity, and having a pressure supply passage at a first end and a radially extending pressure control passage; (2) a feed supply tube positioned in said central cavity, said feed supply tube including an outer diameter in communication with the pressure control passage, and including an inner bore operably connected to said pressure supply passage, said feed supply tube being supported in said central cavity of said fluid control body by way of a radially and axially extending wall, said wall being segmented into a plurality of longitudinally extending flow chambers, said feed supply tube including a valve receiving chamber area; (3) a valve seat portion being made of a metallic material and press fit into said fluid control body, said valve seat portion including a valve seat and a passage in communication between said valve seat and said pressure control passage; (4) a valve contained in said valve receiving chamber operable to selectively close off communication between said pressure supply passage and said pressure control passage; (5) a solenoid for opening said valve in response to a signal, wherein said solenoid includes a central axis and has a coil wound around a bobbin, spaced from and positioned around said central axis, said coil having radially stepped radial inner diameters; (6) a casing member for attaching said solenoid to said fluid control body; a portion of said casing member extending into the stepped portion of said coil for forming a flux tube therein; (7) an armature axially movable within said bobbin; (8) a pole piece assembly adjacent said armature and interposed between said bobbin and said fluid control body; and (9) a control rod extending along said central axis and through said pole piece assembly for opening of said valve, said control rod including a tapered end.
[0012] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0014] FIG. 1 is a cross-sectional view of the solenoid control valve of the present invention;
[0015] FIG. 2 is a side view of the control valve body of the present invention;
[0016] FIG. 3 is a top view of the control valve body of the present invention;
[0017] FIG. 4 is a sectional view taken along line 4 - 4 of FIG. 2 ;
[0018] FIG. 5 is a sectional view taken along line 5 - 5 of FIG. 2 ;
[0019] FIG. 6 is a sectional view taken along line 6 - 6 of FIG. 2 ;
[0020] FIG. 7 is a sectional view taken along line 7 - 7 of FIG. 2 ;
[0021] FIG. 8 is a second partially broken away sectional view of the valve body of the present invention;
[0022] FIG. 9 is a performance curve of the operational characteristics of the present invention when operating at 40 psi;
[0023] FIG. 10 is a performance curve of the operational characteristics of the present invention when operating at 120 psi; and
[0024] FIG. 11 is a performance curve of the operational characteristics of the present invention when operating at 215 psi.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
[0026] Referring to the Figures generally, and FIGS. 1-8 specifically, there is provided a solenoid control valve generally shown at 10 , in accordance with the general teachings of the present invention. The solenoid control valve includes a fluid control body generally indicated at 12 , and a solenoid portion generally indicated at 14 . By way of a non-limiting example, the fluid control body 12 is preferably adapted for being received in a fluid manifold housing in a valve body of a transmission.
[0027] The fluid control body 12 preferably includes a central cavity 16 , wherein the central cavity 16 preferably includes a fluid supply passage 18 and a fluid control passage 20 . These passages preferably communicate with either a supply line in the manifold or a control line, as is readily known in the art. A feed supply tube 22 is preferably integrally molded with the fluid control body 12 . Feed supply tube 22 preferably includes an outer diameter 24 , which is in communication with the control passage 20 , and preferably includes an inner bore 26 in communication with the supply passage 18 through laterally extending port 28 . The feed supply tube 22 is preferably supported in the cavity 16 by at least one or more segmented areas 30 , best shown in FIG. 6 . Preferably, there are three segmented flow passages on each side of the feed supply tube 22 , as shown in FIG. 6 . The feed supply tube 22 preferably includes a valve receiving area 32 .
[0028] A valve seat-forming portion 34 is preferably made out of a metal material and is press fit into the feed supply tube 22 . The outer diameter of the valve seat-forming portion 34 is preferably press fit into the valve receiving area 32 . By this arrangement, fluid passage is allowed to flow axially through the segmented area 30 , while the webs forming the segmented area absorb press loads on the valve seat member 34 . An alignment shelf 36 is preferably provided on the control body for providing proper depth of alignment of the valve seat member 34 . A ball valve 38 is preferably held between the valve seat 40 and the valve retainer portion 32 . A return spring 35 preferably biases the ball valve 38 toward valve seat 40 . The valve seat member 34 preferably provides a passageway 42 to the control passage 20 . The valve 40 is preferably operable to selectively cut off supply of flow from the supply channel 18 to the control passage 20 .
[0029] The valve seat member 34 is preferably press fit into the flux washer 62 forming a pole piece assembly 64 . In a preferred embodiment, the flux washer 62 is preferably a stamped member and the valve seat member 34 is preferably a screw turned member. Assembly of these pieces together reduces the cost of the assembly.
[0030] Solenoid portion 14 is preferably secured to the fluid control body 12 . An O-ring 44 is preferably disposed between the fluid control body 12 and the pole piece assembly 64 . The solenoid 14 preferably includes a central axis A-A and has a coil 46 wound around a nonmagnetic bobbin member 48 . The bobbin member 48 is preferably stepped radially, and includes a radially outward wall 52 and a radially inward wall 54 . A one-piece casing member 50 preferably includes a radially extending flux tube forming annular portion 56 . The casing 50 also preferably crimpingly attaches the solenoid 14 to the body 12 by way of the crimped portion 58 . An armature 60 is preferably provided, which fits within the wall 54 and is axially movable in response to a current in the coil. The pole piece assembly 64 is preferably secured between the lower portion of the bobbin 48 and the control body 12 . The pole piece assembly 64 preferably includes a center orifice 64 , which allows the valve seat member 34 to be press fit therein.
[0031] The control rod 66 preferably has a tapered upper end 67 and is movable within the member 34 . The armature 60 preferably moves the control rod 66 . The tapered pin preferably reduces magnetic flux shorting, thereby improving performance without sacrificing strength.
[0032] Assembly standoffs 69 are preferably provided. These standoffs are preferably axially radially extending rib members. These rib members act to preferably provide precise positioning of the casing 50 in the final solenoid control valve of the present invention. Specifically, a retention groove 76 is preferably provided that is engaged by a clip member (not shown) when securing the control valve 10 in a fluid manifold housing in a valve body of a transmission, for example. In the past, getting the fluid control body 12 axially positioned properly in the manifold housing for alignment of the clip with slot 76 has been problematic. These ribs ensure precise alignment during assembly for the clip to engage slot 76 . A preferred embodiment has two ribs 76 spaced 180° apart and a wider rib 76 a positioned 90° between these ribs 76 .
[0033] The coil 46 , bobbin 48 and coil contacts 70 are preferably overmolded to form connector 72 . This forms a one-piece assembly that also preferably includes an armature cage assembly 72 A portion that preferably holds armature 60 and its biasing spring 74 in place upon securement of the casing 50 to the fluid control body 12 .
[0034] Set forth in FIGS. 9 through 11 are transfer function progressions showing the duty cycle performance of the pulse width modulation of the solenoid of the present invention when operating with 40, 120 and 215 pounds per square inch of fluid pressure applied at the supply passage. As shown therein, the performance characteristics are optimized in the design of the present invention.
[0035] The description of the invention is merely exemplary in nature and, thus, 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. | A pulse width modulated solenoid control valve is described, wherein the valve includes a polymer fluid control body. The body includes a segmented fluid flow path for providing strength to the fluid control body assembly. Stand off ribs are provided to improve assembly into a control manifold. A casing forms an integral flux tube. A tapered push rod is used to reduce flux shorting. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the treatment of organic wastewater and an apparatus therefor and more particularly, to an organic wastewater treatment process and an apparatus therefor for treating organic wastewater, especially wastewater having higher concentrations of various components, such as, for example, alcohol wastewater, grape fermentation wastewater, beer wastewater, coffee wastewater or starch wastewater which generally have concentrations 3,000 to 30,000 ppm of B.O.D.
2. Description of the Prior Art
Various types of organic wastewater treatment processes are known in the art. In such processes, the suspended contaminants in a liquid sludge stream are commonly removed by a gravity thickening separation procedure. However, such processes suffer from a number of disadvantages such as, for example, (1) treatment takes a long time, (2) it is very expensive to install the treatment apparatus and maintain it, and (3) the process has a low yield.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved organic wastewater treatment process and an apparatus therefor.
Another object of the present invention is to provide a combined stage process system and an apparatus having a number of unique design features for improving liquid treatment efficiency and cost saving.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
Briefly described, the present invention relates to an organic wastewater treatment process which combines a sludge blanket layer process with a medium layer member process for improving liquid treatment efficiency and cost savings.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 schematically shows the overall process according to the present invention;
FIG. 2 schematically shows the gradually moving layer depending on the incoming velocity according to the present invention;
FIG. 3 schematically shows the formation of a sludge blanket layer according to the present invention;
FIGS. 4(a) and 4(b) show the separated state of a particle and the particle layer formed at a medium layer according to the present invention;
FIG. 5 schematically shows the forming process of the sludge blanket layer according to the present invention;
FIG. 6 is an enlarged perspective view of the medium layer member according to the present invention;
FIG. 7 is a top plan view of the media layer member according to the present invention;
FIG. 8 schematically shows a small unevenness formed at the media layer according to the present invention; and
FIG. 9 schematically shows a floc in detail.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention, the organic wastewater treatment process and the apparatus therefor are shown in FIGS. 1, 2, and 3. The organic wastewater treatment process comprises a sludge blanket layer process and a medium layer member process.
At the first stage of the sludge blanket layer process, over 80% of the wastewater is treated, and at the second stage of the medium layer member process, the remaining untreated organic wastewater is treated. A medium layer member 2 having a certain degree of inclination is formed in the upper and middle portion of a vessel 1. A certain lower space 3 is formed to an inlet pipe 5 within the lower portion of the vessel 1. A sludge blanket layer 15 is formed in the right lower portion of the thick medium layer member 2. At this time, the factor for forming the sludge blanket layer 15 depends on the velocity of the incoming wastewater, the height of the lower space 3 to the medium layer member 2 and the slope of the medium layer member 2.
The sludge blanket layer 15 contains a group of flocs 14 composed of a highly concentrated microorganisms. It is known by experimental record that the blanket layer process can treat almost 80% of the contaminant concentration in the wastewater so that the process rate would be extremely high, even if the incoming wastewater has a very high contaminant concentration since the organic wastewater is thoroughly contacted with the microorganisms which are highly concentrated.
The process for forming the sludge blanket layer 15 is as follows:
Organism membranes are formed at the surface of the medium layer member 2 which is inclined at an angle so that they segregate partly and fall to the lower space through the inclined surface thereof. The small size of the organism membranes allows them to fall to the lower space 3 into the incoming wastewater. These membranes form the group of flocs 14 by contacting one another in a flowing state and the formed floc exhibits water buoyancy. Also, small bubbles 16 produced by the incoming wastewater and produced continuously by anaerobic fermentation attach to these microorganism flocs 14. And the flocs 14 rise to the right lower portion of the medium layer member 2. Thus, the flocs 14 of organism membranes gather in the lower portion of the medium layer member and these gathered flocs 14 actually become the thick sludge blanket layer 15.
Since the surface of the segregated organism membranes exhibits sticky phlegmatic properties like slime, the microorganism membrane of particles 13 in the flowing state within the lower space 3 easily become flocs 14, and the flocs 14 gathered in the lower portion of the medium layer member 2 have high cohesive properties. Thus, the cohered organism membranes begin to stick at the lower surface of the medium layer member 2 and new flocs 14 are united gradually with the sticky flocs 14 by coattraction and the adhesive properties. The blanket layer 15 is formed to the extent of breaking the balance between the upward power caused by the velocity of the incoming wastewater and the weight of the blanket layer 15. Since a large surface unevenness exists in the lower surface of the medium layer member 2, the adhesive properties of the flocs 14 and the medium layer member 2 are high, and the technical construction of the blanket layer 15 which is added to the lower portion of the medium layer 2 is important in the present invention. This relates to the velocity of the wastewater flowing to the lower space 3, the extent of formation of bubbles 16 formed from the reduction in pressure when the bubbles 16 flow from the inlet pipe 5 into the large lower space 3, the extent of formation of gas by anaerobic fermentation according to occupying time within the process vessel 1, the slope of the medium layer member 2, and the height ratio of the medium layer member 2 and the lower space 3, etc.
As shown in FIG. 1, the medium layer member 2 is formed to be 0.55-0.65 H disposed in the middle portion of the process vessel 1 having a height H, an inflow pipe 5 is disposed having a plurality of nozzles 4 perforated downwardly and placed by forming the lower space 3 to be 0.2-0.3 H in the lower portion thereof, and an outlet pipe 7 is connected integrally with the vessel 1 to be connected with an upper space 6 having a height of 0.1-0.2 H for the filtrate.
An air outlet pipe 8 for methane and carbon dioxide (CH 4 +CO 2 ) produced by anaerobic fermentation is formed in the highest upper space 6.
The medium layer member 2 is composed of a plurality of media layers 9 and the media layers 9 are stacked up to 3-5 layers with the surfaces contacting each other. A bent portion 10 of each of the media layers 9 is formed like a wave and is inclined at an angle of 55-65°. Therefore, a plurality of gaps 11 are formed by placing the contacting media in a crisscross pattern. The gaps 1 connect in a zigzag pattern. The ratio of the gaps 11 are formed over 90% of the surface area of the media layers 9 and the specific surface area is over 120 m 2 /m 3 .
Furthermore, the surface area is enlarged by forming a minute unevenness 12 so that flocs 14 composed of the particles 3 stick well to the lower end portion of each media layer 9 in the lowest layer and do not separate therefrom.
Generally, when only the pure medium layer process is utilized after filling up the vessel 1 with the wastewater without forming the blanket layer 15, the required hydrographical period is about 7-10 days so that the rate of treatment is 80-85%, even if much of the media layer 9 is filled up. However, in the present invention, since the medium layer member and the blanket layer 15 formed at the right lower portion of the medium layer member 2 are co-treated by stages, the rate of treatment is 90-95%, even if the required processing period is 1-5 day. It is caused by the thickness of the blanket layer 15, that is, the particles 13 of the sludge which are separated and roll down from the surface inclined at an angle of 55-65° can be gathered in almost uniform thickness because the incoming wastewater flows through layers smoothly and regularly in step by step procedure as shown in FIG. 2 when the vessel 1 has the above described structure and in addition, the rising velocity of wastewater flowing into the lower space 3 is kept with 0.5-2.5 m/day. Since the blanket layer 15 also cannot be dispersed and broken down, 0.5-2.5 m/day of the inflow velocity of wastewater is very important factor, and the advantage effect is that sludge flocs 14 are drawn to the lower portion of the medium 9.
Furthermore, the reason that the medium layer member 2 is inclined to 55-65°, is to properly control incoming wastewater and prevent microorganisms from clogging the medium gaps 11 in the form of microorganism flocs 14.
In the case that the slope of the medium layer 2 is over 65°, the microorganism within the medium layer member 2 and separated from the medium layer member 2 can be outcoming without floating and depositing. In the case that the slope of the medium layer member 2 is under 55°, it is expected to have a high treatment rate for preventing the outcoming of produced microorganisms but the treatment rate becomes uneconomical. Because there is the possibility that the gaps 11 of the medium layer member 2 clog due to the stagnating state of the separated microorganisms, the floating microorganisms within the medium layer member 2 and an inflow solid.
Therefore, the angle range of the slope of the medium layer member 2 is one of the important structural features in order to form the blanket layer 15 according to the present invention.
Furthermore, in the present invention, the structure of the vessel 1 is divided among the medium layer member 2, the lower space 3, and the blanket layer -5 formed in the lower portion of the medium layer member 2. Because of the inflow velocity of the wastewater, the gradual movement of layers caused by the velocity, and the production of bubbles 16 of methane and carbon dioxide gas during a short time, the sludge flocs 14 move upward to the medium layer member 2 and the blanket layer as a support blanket layer 15. Thus, the blanket layer 15 is formed thickly and is highly concentrated. The thick blanket layer 15 processes over 80% of highly the concentrated wastewater. It is an advantageous condition in forming and keeping the blanket layer 15 that the continuously producing bubbles 16 also support the blanket layer 15 so that the layer 15 is not broken down when the inflow velocity is kept within 0.5-2.5 m/day.
As shown in FIG. 3, according to the present invention, the treatment process is as follows:
(a) When the wastewater incoming into the pipe 5 flows downwardly through the nozzles 4, the microorganisms feed within the vessel 1 which provides a new environment and anaerobic bacteria proliferate, and decompose organic substances.
(b) In an early stage, the light microorganism rises with the fluid without deposition due to the rising velocity of the incoming wastewater.
(c) The risen microorganism follow the inclined medium layer member 2 attached to the surface of the media layer 9. Bacteria which form methane and carbon dioxide attach easily to the surface of matter or other bacteria.
(d) As the reaction proceeds, a large number of microorganisms attach to the surface of the medium 9, but in the early stage, a minute particle layer 13a is formed because of the self attaching property of bacteria as shown in FIG. 4(a).
(e) When the particle layer 13a forms to a 1-2 mm thickness at the surface of the medium layer 9, shearing force caused by the rising velocity o the fluid and its specific gravity (weight) force the particles to separate and fall down as shown in FIG. 4(b).
(f) As the particles 13 fall down, the sinking velocity thereof increases because of gathering with other particles 13.
(g) The particles 13 are deposited at the lower portion of reaction vessel 1, but when the flocs 14 become big because of gathering with other particles 13 continuously, the sinking velocity increases.
(h) At this time, since the already deposited particles 13 in the lower portion of the vessel 1 may rise again by the rising velocity of fluid and the bubbles 16 of produced gas and may form a larger floc 14 by attaching to themselves, a lot of the particles 13 remain or float into the lower portion of the vessel 1.
(i) As the depositing velocity of the flocs 14 and the rising velocity of fluid balance in the right lower portion of the media layer 9, the big flocs 14 deposited by following the medium surface form the blanket layer 15. The position which the depositing velocity and the rising velocity balance is about 20-30% under from the surface of the media layer 9.
(j) The microorganism substance incoming from the lower portion of the vessel 1 is dissolved by the microorganism particles 13 in the lower portion of the vessel 1, and wastewater processed about 80% passes through the blanket layer 15 but the microorganisms cannot pass through and accumulate in the lower portion.
(k) The processed wastewater through the blanket layer 15 passes through the medium layer member 2, and the remaining organic substance floats in the medium layer member 2 or is dissolved by the attaching microorganisms. Thereafter, it is drained through the outlet pipe 7 as clean water.
(l) The newly formed particles 13 formed by decomposition of organic substances in the medium layer member 2 deposit on the blanket layer 15 according to the process and the sludge blanket layer 15 becomes more thick. However, if the blanket layer 15 exceeds a certain thickness, a portion of blanket layer 15 is deposited and the rest of the blanket layer remains due to the fact that the equilibrium of the deposition velocity and rising velocity has been broken.
According to the present invention, as the microorganisms cause decomposition of organic substances at a high rate within 1-5 days of the hydrographic staying time, the process time is very short, the efficiency of production increases, produced methane gas can be used as a source of energy, and the arrangement expense, chemical expense, electricity expense and operating expense can be reduced, while the quality of water is good, and thus, the effect on an ecosystem can be minimized when the wastewater is discharged into a river.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included in the scope of the following claims. | An organic wastewater treatment process which combines a sludge blanket layer process with a media layer process for improving liquid treatment efficiency and cost savings. | 8 |
BACKGROUND OF THE INVENTION
[0001] Organizations and businesses of all sizes and missions, buy a diverse array of assets. In diversity, these can extend from computer equipment to cattle. Yet the control, movement, resources available and management of these assets, the ongoing costs to maintain them, their purpose and even where they are located is not obvious to many of their owners. In addition many organizations must comply to industry or government standards with respect to the maintenance of such assets which adds significantly to the “need to know” factors surrounding them. The reliance by organizations on these often high value assets is constant and growing. Yet the costs of securing, managing and maintaining assets are prohibitively expensive and often are not visible to key stakeholders. Decision making as a result occurs in a financial and needs analysis vacuum. The challenge is exacerbated by organizations being at breaking point in terms of budgetary, technology, physical space constraints and a shortage of staff. Due to a lack of transparency and visibility every asset has the potential of being used inefficiently, lost all together or even stolen. Today many organizations cannot find assets, tell you the value of them or their use or be able to see changes in their status. Yet countless hours are spent by employees trying to achieve these through basic applications, spreadsheets and in many cases manual processes. In today's world there are real question marks as to what value these assets are really delivering and much time is wasted in this pursuit. While technology has revolutionized almost every area of business life, technological advancement has paradoxically made it difficult to efficiently take control over these challenges.
[0002] There are numerous point based solutions that seek to address parts of the problem but there has not until now been a total solution that covers assets in multiple locations that can deliver critical information in the right form to multiple stakeholders. Point based systems are often very expensive, do not embrace the latest technologies and either can't integrate with other important systems organizations have or find doing so extremely difficult. Their mechanisms are often too cumbersome when seeking to manage assets day to day. It is also typically very tedious and manually intensive to maintain up-to-date information in these solutions.
SUMMARY
[0003] The present invention provides a system for semantically modeling relationships and dependencies between groups, enclosures, assets, and support entities according to an industry specific manner. An exemplary system includes a user interface device, a relational database, and a processor in data communication with the database and the user interface device. The processor receives relationship and dependency information between groups, enclosures, assets, and support entities for a corporation from the user interface device, receives attributes with associated measurements for the groups, enclosures, assets, and support entities for the corporation from the user interface device. The attributes with associated measurements are formatted according the specific industry of the corporation. The relationship and dependency information and the attributes are stored with associated measurements into the relational database.
[0004] In accordance with further aspects of the invention, the system includes a plurality of data transmission devices. Each of the plurality of data transmission devices associated with one of the groups, enclosures, assets, and support entities for the corporation. The plurality of data transmission devices include data of the associated one of the groups, enclosures, assets, and support entities. The system also includes a plurality of data collection devices in signal communication with the processor and the plurality of data transmission devices. The plurality of data collection devices retrieves the data from the plurality of data transmission devices. The data transmission devices and data collection devices include at least one of radio frequency identification (RFID) tags, antenna, readers or concentrators. The processor enters the data received from the data collection devices into the relational database.
[0005] In accordance with other aspects of the invention, the processor executes a plurality of data Application Program Interfaces (APIs) that integrate data received from the data collection devices into a comprehensive view of the groups, enclosures, assets, and support entities based on the relational database.
[0006] In accordance with still further aspects of the invention, the processor allows a user to create at least one of a graphical or text based report regarding one or more of the groups, enclosures, assets, and support entities. The report includes at least one of absolute values, ranges or comparative values of at least a portion of the attributes. The report filters, sorts, or orders the groups, enclosures, assets, and support entities.
[0007] In accordance with yet other aspects of the invention, the processor calculates return on investment based on the asset data. The asset data includes a cost to replace value or a cost of ownership value.
[0008] In accordance with still another aspect of the invention, the processor allows a user to define one or more perimeters within which each of the assets are located and to identify the assets within the one or more perimeters.
[0009] In accordance with still further aspects of the invention, the database includes a supplier database that stores all assets in an individual group and across all groups.
[0010] In accordance with yet another aspect of the invention, the system includes a remote access device that is in data communication with the processor via a public or private data network. The remote access device includes a mobile device, a laptop computer, a tablet computer or a desktop computer.
[0011] In accordance with further aspects of the invention, the processor generates a graphical user interface that provides a three dimensional (3D) visualization of the groups, enclosures, assets, and support entities.
[0012] In accordance with still further aspects of the invention, the processor allows a user to modify records of the assets, enclosures, groups, and support entities, display values of the attributes, and edit the values of the attributes within the relational database.
[0013] In accordance with additional aspects of the invention, the processor allows a user to semantically map the received attributes from disparate sources and the supplier database. The semantically mapped attributes provide context to the received attributes and the attributes' relation to assets, enclosures and groups.
[0014] In accordance with yet additional aspects of the invention, the processor allows a user to uniquely identify a location of an asset and physical orientation based on data received using at least one of a Radio Frequency Identification (RFID) system, a Real-time Locating System (RTLS) or Global Positioning System (GPS).
[0015] In accordance with still additional aspects of the invention, the processor allows a user to uniquely identify asset identifiers to associate, capture, monitor and timestamp, data with other data pertaining to the asset within the system.
[0016] In accordance with other additional aspects of the invention, the processor allows a user to share asset information comprising at least one of a physical asset component data, financial data, contractual data and utilization data and permit the management, display and analysis of asset information on a single user interface.
[0017] In accordance with still other aspects of the invention, the processor allows a user to perform at least one of a query, an interrogation, a forecast, a what if scenario and to perform modeling of return on investment based on any change to assets, enclosure and groups.
[0018] In accordance with further aspects of the invention, the processor provides trending information and analysis of the user's industry as compared to the user's specific asset deployments.
[0019] In accordance with still further aspects of the invention, the 3D visualization includes annotation of groups with at least one of bounds, extents, photographs and related media elements, wherein the 3D visualization comprises at least one of a diagrammatic image or a figurative image. The user interface allows a user to perform at least one of browse, find, create, update or delete information associated with the assets, the enclosures, the groups, and the support entities, and the relationship information. The processor can show via the graphical user interface changes to status of an asset. The processor generates a unique identifier based on a user defined asset search. The unique identifier provides a visual indication of the presence and location of all assets that match the user defined asset search. The processor allows a virtual walkthrough of the 3D visualization as presented on the display device based on user entered commands from the user input device. The processor displays asset attributes based on a user entered selection signal from the user input device during the virtual walkthrough.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Preferred and alternative examples of the present invention are described in detail below with reference to the following drawings:
[0021] FIG. 1 is a block diagram showing a conventional computer system, various computer peripherals, and various communication means formed in accordance with an embodiment of the invention;
[0022] FIG. 1-1 is a topological view of the system and its components according to the embodiment of the current invention;
[0023] FIG. 2 is a logical, semantic view of the relationships between group, enclosure and asset entities and examples of such interrelations used by the system of FIG. 1 for capturing and managing assets in disparate locations, indoors, outdoors, locally or geographically dispersed according to an embodiment of the invention;
[0024] FIG. 2-1 shows a typical example of FIG. 2 as it relates to datacenters providing a logical, semantic view of the relationships between group, enclosure and asset entities within a datacenter environment.
[0025] FIG. 3 is a further schematic sample view of the system for capturing and managing datacenter assets in disparate locations and how other information from other data sources are semantically mapped to entities according to an embodiment of the invention;
[0026] FIG. 4 is a schematic view of the underlying four tier architecture of the system for capturing and managing assets in disparate locations and how that information is stored, managed and communicated according to an embodiment of the invention;
[0027] FIG. 5 shows a datacenter example of the topological schematic view of the system for capturing and managing inventoried and tagged assets in disparate locations and how that information once in the database is accessed by user and allows specific requirements to be achieved according to an embodiment of the invention; and
[0028] FIGS. 6 through 17 show illustrative embodiments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, one skilled in the art will understand that the invention may be practiced without these details or with various combinations of these details. In other instances, well-known systems and methods associated with, but not necessarily limited to, asset management and methods for operating the same may not be shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments of the invention.
[0030] An embodiment of the invention is deployed on or used in conjunction with, but is not limited to an internet based service and a browser. There are pluralities of components for managing critical assets, integrating all the critical information pertaining to the asset and delivering this information in the needed form for individual stakeholders. Stakeholders have the ability to spatially navigate to an assets location, for example in a building, a field, locally or across the globe, in 2 or 3 Dimensions from their desktop, even when they are hundreds or thousands of miles from the physical asset location. These components may include but are not limited to a desktop browser, mobile device applications, asset information repositories and API's; local or remote information synchronization and maintenance of information pertaining to assets and their interdependencies.
[0031] FIG. 1 is a diagram showing a conventional computer, various computer peripherals, and various communication means formed according to an embodiment of the invention. For purposes of brevity and clarity, embodiments of the invention may be described in the general context of computer-executable instructions, such as program application modules, objects, applications, models, or macros being executed by a computer, which may include but are not limited to personal computer systems, hand-held devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, mini computers, mainframe computers, and other equivalent computing and processing sub-systems and systems. Aspects of the invention may be practiced in distributed computing environments where tasks or modules are performed by remote processing devices linked through a communications network. Various program modules, data stores, repositories, models, federators, objects, and their equivalents may be located in both local and remote memory storage devices.
[0032] By way of example, a conventional personal computer, referred to herein as a computer 100 , includes a processing unit 102 , a system memory 104 , and a system bus 106 that couples various system components including the system memory to the processing unit. The computer 100 will at times be referred to in the singular herein, but this is not intended to limit the application of the invention to a single computer because, in typical embodiments, there will be more than one computer or other device involved. The processing unit 102 may be any logic processing unit, such as one or more central processing units (CPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. Unless described otherwise, the construction and operation of the various blocks shown in FIG. 1 are of conventional design. As a result, such blocks need not be described in further detail herein, as they will be understood by those skilled in the relevant art.
[0033] The system bus 106 can employ any known bus structures or architectures, including a memory bus with memory controller, a peripheral bus, and a local bus. The system memory 104 includes read-only memory (“ROM”) 108 and random access memory (“RAM”) 110 . A basic inputoutput system (“BIOS”) 112 , which can form part of the ROM 108 , contains basic routines that help transfer information between elements within the computer 100 , such as during start-up.
[0034] The computer 100 also includes a hard disk drive 114 for reading from and writing to a hard disk 116 , and an optical disk drive 118 and a magnetic disk drive 120 for reading from and writing to removable optical disks 122 and magnetic disks 124 , respectively. The optical disk 122 can be a CD-ROM, while the magnetic disk 124 can be a magnetic floppy disk or diskette. The hard disk drive 114 , optical disk drive 118 , and magnetic disk drive 120 communicate with the processing unit 102 via the bus 106 . The hard disk drive 114 , optical disk drive 118 , and magnetic disk drive 120 may include interfaces or controllers (not shown) coupled between such drives and the bus 106 , as is known by those skilled in the relevant art. The drives 114 , 118 , 120 , and their associated computer-readable media, provide nonvolatile storage of computer readable instructions, data structures, program modules, and other data for the computer 100 . Although the depicted computer 100 employs hard disk 116 , optical disk 122 , and magnetic disk 124 , those skilled in the relevant art will appreciate that other types of computer-readable media that can store data accessible by a computer may be employed, such as magnetic cassettes, flash memory cards, digital video disks (“DVD”), Bernoulli cartridges, RAMs, ROMs, smart cards, etc.
[0035] Program modules can be stored in the system memory 104 , such as an operating system 126 , one or more application programs 128 , other programs or modules 130 and program data 132 . The system memory 104 also includes a browser 134 for permitting the computer 100 to access and exchange data with sources such as web sites of the Internet, corporate intranets, or other networks as described below, as well as other server applications on server computers such as those further discussed below. The browser 134 in the depicted embodiment is markup language based, such as Hypertext Markup Language (HTML), Extensible Markup Language (XML) or Wireless Markup Language (WML), and operates with markup languages that use syntactically delimited characters added to the data of a document to represent the structure of the document. Although the depicted embodiment shows the computer 100 as a personal computer, in other embodiments, the computer is some other computer-related device such as a personal data assistant (PDA), a cell phone, or other mobile device.
[0036] The operating system 126 may be stored in the system memory 104 , as shown, while application programs 128 , other programsmodules 130 , program data 132 , and browser 134 can be stored on the hard disk 116 of the hard disk drive 114 , the optical disk 122 of the optical disk drive 118 , andor the magnetic disk 124 of the magnetic disk drive 120 . A user can enter commands and information into the computer 100 through input devices such as a keyboard 136 and a pointing device such as a mouse 138 . Other input devices can include a microphone, joystick, game pad, scanner, etc. These and other input devices are connected to the processing unit 102 through an interface 140 such as a serial port interface that couples to the bus 106 , although other interfaces such as a parallel port, a game port, a wireless interface, or a universal serial bus (“USB”) can be used. A monitor 142 or other display device is coupled to the bus 106 via a video interface 144 , such as a video adapter. The computer 100 can include other output devices, such as speakers, printers, etc.
[0037] The computer 100 can operate in a networked environment using logical connections to one or more remote computers, such as a server computer 146 . The server computer 146 can be another personal computer, a server, another type of computer, or a collection of more than one computer communicatively linked together and typically includes many or all the elements described above for the computer 100 . The server computer 146 is logically connected to one or more of the computers 100 under any known method of permitting computers to communicate, such as through a local area network (“LAN”) 148 , or a wide area network (“WAN”) or the Internet 150 . Such networking environments are well known in wired and wireless enterprise-wide computer networks, intranets, extranets, and the Internet. Other embodiments include other types of communication networks, including telecommunications networks, cellular networks, paging networks, and other mobile networks. The server computer 146 may be configured to run server applications 147 .
[0038] When used in a LAN networking environment, the computer 100 is connected to the LAN 148 through an adapter or network interface 152 (communicatively linked to the bus 106 ). When used in a WAN networking environment, the computer 100 often includes a modem 154 or other device, such as the network interface 152 , for establishing communications over the WANInternet 150 . The modem 154 may be communicatively linked between the interface 140 and the WANInternet 150 . In a networked environment, program modules, application programs, or data, or portions thereof, can be stored in the server computer 146 . In the depicted embodiment, the computer 100 is communicatively linked to the server computer 146 through the LAN 148 or the WANInternet 150 with TCPIP middle layer network protocols; however, other similar network protocol layers are used in other embodiments. Those skilled in the relevant art will readily recognize that the network connections are only some examples of establishing communication links between computers, and other links may be used, including wireless links.
[0039] The server computer 146 is further communicatively linked to a legacy host data system 156 typically through the LAN 148 or the WANInternet 150 or other networking configuration such as a direct asynchronous connection (not shown). Other embodiments may support the server computer 146 and the legacy host data system 156 on one computer system by operating all server applications and legacy host data system on the one computer system. The legacy host data system 156 may take the form of a mainframe computer. The legacy host data system 156 is configured to run host applications 158 , such as in system memory, and store host data 160 such as business related data.
[0040] A 3-Dimensional (3D) Visualization component provides a real-time 3D visualization, navigation and reporting of all assets both physically and virtually. The 3D Visualization component automates the monitoring, analysis and interrogation of assets to optimize every functional aspect. The 3D Visualization component is accessed though a powerful web graphical user interface (GUI) dashboard.
[0041] Using the 3D Visualization component a user can select an asset or assets that are of interest. The Asset Halo Glow Identifier maps and highlights all assets that match the specific asset search and allows the visual differentiation between selected and non-selected assets. Non-exhaustive lookup examples would include assets that are of a specific age, livestock of a particular breed, assets that are moving versus not moving and assets that need servicing, Once the visualization has highlighted where those assets are the user can virtually walk up to them. Once there, the user can click or mouse-over on the asset or series of assets and be shown detailed attribute information about the Asset and all its credentials based on the particular stakeholder view. This for example could be financial information about the Asset, when it was purchased, weight, consumption, and how much is it costing. As another example one may want to know details about the movement of an asset; where it has been over the past month and where it is now. Whatever view the stakeholder wishes, based on their role, can be satisfied by the 3D Visualization component.
[0042] A semantic database is a hub that centralizes and models all information and brings assets into a unified intelligent infrastructure. The database is a hosted database accessed through a powerful web GUI dashboard that allows customers to manage, analyze, report on and visualize assets, assets in buildings andor outdoors and all the information pertaining to them. The database provides the business intelligence and knowledge based on which asset management, location management, capacity management and planning takes place. All existing asset information, their utilization, location, maintenance schedules and financial data is captured by the database. Each Organization, Enclosure, and Asset, and support entities having attributes with associated measures specific to their industry. By way of example:
a. A non-exhaustive example for an Asset modeling a computer would be weight, power, cooling, height, width, length b. A non-exhaustive example for an Asset modeling livestock would be weight, birth date, inoculations, breed and sex
[0045] The database allows customers to intuitively manage resource usage, forecast and introduce new capacity simply and quickly. Stakeholders from across an organization including asset owners, facility managers, administrators and finance can access the critical information they need from the database eliminating the cost and expense of having multiple sources and the errors that inevitably result.
[0046] The system integrates and semantically aligns information directly accessed from source providers of assets capturing all key specification data and automatically populating this information as entities within the database for existing and newly acquired assets. It further enables the same from any other valid source of information that allows a complete picture of an asset and all its attributes. Such information is downloaded and stored in the database. In doing so, additional entities can be added to model behaviors and relationships specific to each Industry.
a. In the IT industry for example, a Project entity can be created which tracks such things as project budget and name, and have relationships to the Organizations and Assets involved. b. In the livestock industry, a Contract entity could be added, which then has relationships to the animal involved in a given sales contract, specifies the price per head, and has relations to the Organizations representing the buyer and seller of the cattle.
[0049] The system allows users to undertake detailed analysis of assets based on all the multi-dimensional information provided. It provides comprehensive “what if” and “time machine” capabilities that allows users to model scenarios or see the status of an asset in a snapshot moment in time. One can further for example draw comparisons of existing assets with alternatives, challenge methods for asset optimization, use and deployment, and identify any costs to replace or extend their use.
[0050] The system captures and consolidates asset data pertaining to all customer using the system within an industry. The system then provides back to each customer consolidated trending information pertaining to the assets they collectively have. In doing so the system delivers industry insights to aid the decision making process and learnings from actual dynamics across an industry. Then by way of a single example a customers can review trends in swapping or replacing assets and run replacement scenarios on existing asset with new potential alternatives.
[0051] The system allows the definition and mapping of perimeter extents of an Enclosure through the Perimeter Interface Module. A non-exhaustive example of perimeter types by industry include a datacenter room, a barn, a freight container or a casino room. Assets are the able to be located and identified within the perimeter. The Perimeter Interface Module works with passive and active assets. The Perimeter Interface Module has been designed to be generic and does not require modification for different vertical markets such as Datacenter, Retail, Security, Livestock and Gaming, since it is independent of layered applications and databases that manages and collects asset information for statics output.
[0052] The system allows the unique identification of an Asset. Unique identifiers in a datacenter example would be an asset's serial number combined with the RFID Tag number and signal associated with that asset. The combination of these two attributes enables the system to associate, capture, monitor and timestamp data from other data sources that pertain to the Asset within the system and ensures its accuracy and integrity.
[0053] Through the use of advanced, low cost local Radio Frequency Identification (RFID), Real-time Locating Systems (RTLS) or Global Positioning System (GPS) tags and sensors, the present invention provides a real-time synchronized view between the system and the “real time location of assets geospatially”. Tags and sensors send information to “in-theater” readers, scanners and concentrators, that integrate to the Datacollector and sent via the network whether intranet or internet to the system. The system then monitors asset provisioning, movement and use thereby reducing and in some cases eliminating the need for human intervention in physical “in-theater” monitoring. It provides the ultimate in asset security and theft deterrence identifying an asset's status, immediately flagging all movements to key stakeholders.
[0054] A comprehensive asset and event management Application Program Interface (API) preferably includes a set of API's to support integration of information from disparate sources pertaining to each individual asset or group of assets. These API's support specifying products and the on-boarding of new assets, events and updates, detailed analysis whether historic, current or futuristic and establishing relationships between people and the assets in question andor sharing information with colleagues or important 3rd parties. The ability to share information with other users stakeholders delivers to each broad access to important data that would otherwise be unavailable or require users to manually intervene with disparate sources applications to access the data. The system provides the automation and delivery of an information sharing paradigm through API's into unified Graphical User Interface. API's also provide the ability to obtain aggregate, statistical and individual reporting data, including, but not limited to the type, number, cost, location and usability information about assets.
[0055] Using RFID, RTLS or GPS readers, scanners and concentrators, an audit component identifies moves, additions or changes to an asset. Audit sensors and reader devices, integrated to the Datacollector and sent via the network whether an intranet or the internet to the system which receives downloaded information concerning the assets at a particular locations. The audit component then verifies that all of the assets have an active tag. If not, data entry is performed on new assets. The audit component then performs a tag scan and if an asset is missing, the audit component verifies and records the missing asset; if an asset is new (new, known tag), the audit component performs data entry.
[0056] The present invention has the ability to analyze and make decisions based on the integration of facts concerning every aspect of an asset and use of tools provided to support and validate such decisions.
[0057] All assets have logistical implications, cost to run or maintain, cost to replace, and benefits implications of replacement. In particular it is important to know and plan what alternatives exist and the timing options for replacement. An embodiment of the system provides capabilities for assessing and planning these types of scenarios and provides the mechanisms to properly account for them.
[0058] Information about assets is made available through the system infrastructure, optionally using a GUI. This information may be available to users via standard reports or the “user defined” report building capability for the purposes of managing the effectiveness of assets including their cost to maintain, usability, security, viability end of life and replacement strategy. The system further provides a user defined alert capability that lets key users know when certain important events take place.
[0059] The systems provides the Smart Algorithms module that allows users to seamlessly automate the analysis, data mining, calculation and visualization of return on investment by comparing re-fresh scenarios between current Assets information including but not limited to cost to replace, cost of ownership, consumption, space allocation and performance with future alternatives.
[0060] FIG. 1-1 provides a topological map of the systems and its current components. It shows the inter-relationships between the components and embodiments of the invention.
[0061] FIG. 2 describes an embodiment of the invention in the underlying Omnibus technology architecture namely, a system capable of defining arbitrarily nestable and classifiable entities, which represent purely semantic relationships. There are three primary entity types:
[0062] 1. Groups: Logical groupings of other groupsenclosures i.e. Division, Company, etc such as “Organization” e.g. a company, a farm, a freight liner or a casino
[0063] 2. Enclosures: A Group with ‘extent’, and other attributes. A system capable of defining arbitrarily nestable and classifiable Enclosures, which include both a semantic label, and an extent, a position, and a physical orientation in space relative to its parent or some global coordinate system. Represent organizational units that have a physical presence of some kind. These can be classified arbitrarily, “Server Room”, “Datacenter”, “Container”. They can be associated with users, projects or contracts. They can have other Enclosures or Assets as children. By way of example Enclosures:
Can be used to model a Datacenter, with an Enclosure root node labeled as “Building”, and given a extent modeling the building volume, and its position in latitude and longitude. This has sub-enclosures such as “Floor” and “Room”, each with its own size, and position relative to the parent using the Perimeter Mapping Module. Can be used to model any enclosures within any organization. In the case of a farm, enclosure examples include Field with sub-enclosure Barn with sub enclosure Stall using the Perimeter Mapping Module. Can then be associated with any applicable Group that own(s) them.
[0067] 3. Assets: Physical items with physical presence, physical traits and measurable attributes (Weight, Temperature, Size, Age, Value) and can be classified arbitrarily, such as “Computer Server”, “Horse”, “Painting”. All Assets can contain sub-asset classes.
[0068] FIG. 2-1 describes an embodiment of the invention as it specifically relates to datacenters within the underlying Omnibus technology architecture where the system capable of defining arbitrarily nestable and classifiable entities such as locations, buildings, floors and machine rooms.
[0069] Furthermore, for each area of applicability, Application Specific Entities can be added with their own attributes, which are then associated with an enclosure that contains them.
Computer equipment as Asset entities can be associated with the Enclosure modeling a datacenter room Enclosure on a particular floor Enclosure. Horses as entities can be associated with the stall enclosure they are in and the higher level barn Enclosure.
[0072] FIG. 3 illustrates an embodiment of the invention that allows other objects, groups and their separate trees to be further added to model other special purpose objects, semantic groupings and their interrelationships to existing objects to model and manage the inter-relationships between Groups. These may be for example in a datacenter scenario:
A “Contract” object that can be used to denote the support relationship between a separate Organization providing maintenance services. Groups and AssetsEnclosures encapsulating a cross-department or multi-company project. A “Source” that is the originating organization of the asset facilitating the capture of specific information pertaining to an Asset.
[0076] In this embodiment, the PersistenceData Tier, Business Services and Web Services tiers are implemented using the Java EE 6 platform which enables broad industry integration and inter-operability.
[0077] FIG. 4 is a schematic view of the underlying 4 Tier Omnibus Architecture developed as the underlying technology used for the system according to an embodiment of the invention.
[0078] A PersistenceData Tier provides an abstraction layer with respect to how the data is stored. It deals with storage and retrieval of the data in a storage neutral manner. In the current embodiment, JPA 2.0, a part of the Java EE 6 framework, is utilized to manage storage and retrieval of data from various databases in a vendor neutral manner.
[0079] A Business Service Tier contains the application software and services. This tier is designed to be independent of the persistence data tier so that applications can be built independent of the data storage technology and vice versa. The business logic tier handles enforcing security, validation of data, and enforcement of constraints so as to ensure a consistent model of the system being managed. The current embodiment uses a variety of Java EE6 services and features to provide these features, including Java CDI, EJB 3.1 and JAAS.
[0080] A Web Service Tier provides access to a variety of clients potentially using a variety of technologies, such as REST, Java RMI, and others. The current embodiment of this invention uses the JAX-RS technology supplied by Java EE 6 to provide a REST interface to the underlying services and data. The REST architectural style is widely used on the World Wide Web. Its architecture characterizes and constrains the macro-interactions of the four components of the Web, namely origin servers, gateways, proxies and clients, without imposing limitations on the individual participants. In this way, it provides simplified access to its services to a wide variety of clients. As business needs change, the current embodiment can easily be extended to support other service styles as well, such as JAX-WS, and Java RMI.
[0081] A Client Tier represents external and internal customers interacting with the current embodiment of this invention through a variety of client devices and applications. In the current embodiment of this invention, this is done through its REST based web services interface, but as stated above, the web service tier can be expanded to support clients that utilize different protocol technologies such as RMI.
[0082] FIG. 5 shows a datacenter example of the topological schematic view of the system for capturing and managing assets in disparate locations and how that information is translated into specific user requirements according to an embodiment of the invention. When “Active” RFID technology is deployed, sensor concentrators are deployed and run onsite at a customer location. The Sensor Concentrators capture asset information in real-time or near real-time information from RFID readers which in turn checks the heartbeat. The heartbeat includes a timer that fires, sending heartbeat messages and tag observations including asset temperature updates, reader updates showing motion when a tag moves from one reader to another, activator updates when motion forces the activation of a tag, usually when it moves through an activation field at a door. The Sensor Concentrators send all captured data through the gateway and across secure network, intranet or internet connections to the backend database. Once in the database users can observe what is happening at each location for each asset and manage their needs appropriately.
[0083] Defining Services for Asset Management and a Single Interface for Managing, Analyzing, Visualizing and Reporting
[0084] An embodiment of the invention provides a toolset for managing, analyzing, visualizing and reporting on assets in multiple, disparate locations in a single GUI user interface. Below are two illustrative examples of the systems use, firstly in a datacenter and secondly on a farm.
[0085] Datacenter Example: To populate the system ( FIG. 5 ), the assets are tagged with passive or active RFID tags. These tags are matched with the serial number of the asset to provide the database location; physical building location, room, rack and uPosition, asset information; manufacturer, model, configuration, power rating and other identification information. This information is gathered automatically through sensors and readers, passes through proprietary LightsOn API's and interfaces and then loads into the database. A user may also add assets manually to the database. Once the data capture has been complete the user can choose the manage, analyze, report or visualize options depending on the specific need. The locations can be selected and then asset information uniquely selected allowing any stakeholder, irrespective of their need to get the precise information they desire. This interface focuses on displaying not just the assets themselves, but also their key details and metrics. Once created, the “new datacenter” may be selected by picking it off the drop down bar in the menu window.
[0086] The Manage Capability
[0087] A Manage UI allows a user to see assets captured electronically and create and populate existing or new locations for assets manually. Manage then allows a user to view, analyze, add, change or delete assets. FIG. 6 shows the initial Manage template with a list of typical types of data being captured. Within Manage a user can see in detail the status of assets, which projects they are assigned to, their physical location, the contracts they were procured under, which RFID readers are tracking the asset and the RFID tags associated with the assets. A user can also manage and manipulate the racks in which assets are stored. FIG. 7-1 shows the Manage UI according to an embodiment of the invention.
[0088] Due to the 3 dimensional nature of assets and enclosures and their physical geospatial attributes the system captures the location and orientation of each asset so that it can be identified and tracked on any movement. For example, FIG. 12-1 shows the Manage Capability for datacenter racks highlighting the orientation attributes captured for this type of enclosure including “X” and “Y” co-ordinates and the direction the front of the asset is facing. As another example, FIG. 16 highlights the orientation and geospatial data being captured in a farming scenario.
[0089] The Manage UI allows a user to filter, search and drill down on a specific asset to see the details of each asset that match the criteria selected. One can see information concerning the assets composition, tagging references, environmental factors, key dates, financial and contract information.
[0090] Specific Asset Drill Down
[0091] FIG. 7-2 illustrates a detail asset information or data entry screen.
[0092] The Report Capability
[0093] FIG. 8 shows the Report user interface according to an embodiment of the invention. A Report UI allows a user to select from any of the dimensions, properties or measures needed for any enquiry. The selectable properties and measures available appear in the user defined query and report builder section of the UI and user can apply conditional filters to these attributes as needed. User can further determine the layout of the report choosing which columns of information it will contain. Any multiple of these can be selected by a user.
[0094] Building Queries Using the GUI Report Builder
[0095] The Report UI allows the build out of uniquely required views of information by creating a user defined query that allows the selection of multiple properties to which can be applied selected filters, operators and values to further hone and qualify. These criteria can be added to build a “nested query” capability. This allows any authorized user, irrespective of their need to get the precise information they need. FIG. 9 shows a nested query example and the use of selectable drop down options that are available for each property, filter or operator specific to a single asset property or multiple data requirements to gain a specific user defined view. A user can select any of these attributes to report on by mousing over the property, clicking on it and picking the specific one needed. This process can be repeated with other properties and the user can decide where to position information by grabbing columns in the reported results at the bottom of the screen. Through this process a user builds custom reports, precisely containing the information they need and in the order and format they require.
[0096] Printing Reports and Exporting Queries
[0097] The Report UI allows a user, once the required view of information is reached, to save the query, print normally, create pivot tables, print as an Adobe .pdf format or download the specific information to Microsoft Excel. FIG. 10 shows Export Icons within Report.
[0098] GUI Tools to Select a Locate Criteria
[0099] A Visualize UI provides a three dimensional visualization of each location. One can select the location from those available in a drop down box and then use mouse controls tools to zoom in or out and pan tilt tools. FIG. 11 shows location selection and navigation tools in the Visualize UI.
[0100] Users can filter their selection based on any information including asset type, manufacturer, age, owner, project etc. FIG. 12 shows Drop down filtering criteria.
[0101] In order to orientate and geospatially align assets within their enclosures, the system captures and employs physical location information. FIG. 12-1 is an illustrative example of the orientation and geospatial data captured for a rack enclosure within a datacenter including “X” “Y” co-ordinates and the direction in which the rack is facing. This data is used to virtually map the data center within the Visualize UI.
[0102] The Visualize UI provides a consistent drop-down capability to allow users to select the criteria for the assets they are looking for. FIG. 12-2 shows the HaloGlow effect based on the selection of a single filter attribute. Within this simple datacenter example, all racks containing assets with that filter criteria are highlighted with a HaloGlow. Those that have no matching assets are not highlighted enabling the differentiation between the two.
[0103] Once assets have been highlighted with HaloGlow, users can navigate through the datacenter to a specific asset using the 3D Walkthrough capability. FIGS. 12-3 shows an example of Walkthrough zooming in to a specific asset and then accessing its more detailed attributes by a simple mouse over.
[0104] Three Dimensional Visualization
[0105] Once the filter criteria have been selected, the Visualize UI highlights where the assets that match those criteria are precisely located. By moving the cursor over each asset a “pop-up” box appears to give basic information on the asset in question. The filter criteria is automatically provided unique colors to enhance the user experience and see the varying conditions ranges of that filter. FIG. 13 shows assets conforming to selection criteria.
[0106] Having established the filtering criteria and being able to see the results for a whole datacenter, a user can then zoom in on any specific rack location or asset as they see fit or navigate around the datacenter as if one was literally walking the aisle to see what assets conform to the query. FIG. 14 shows the specific information concerning one specific asset by positioning the cursor over the asset in question.
[0107] Integration between Manage, Report and Visualize
[0108] Due to the full integration of all the embodiments of this solution a user can now click on a specific asset and see all its specific information. FIG. 15 shows by clicking on the asset the system provides complete details and every attribute pertaining to the asset including physical attributes, financial information, age and ownership in a single fully integrated view.
[0109] Farm Example ( FIG. 16 ) To populate the system in this example follows the exact same logic as that show in the datacenter example as does the use of the Manage Capability, Asset Filtering, Report Capability, User Defined Nested Report Builder, Printing Reports, Exporting Queries and GUI Tools. It further gives examples of the system Perimeter modeling capability that in this case would be used to map the extents of farms, fields, stable and stalls and the orientation and geospatial data captured.
[0110] From a visualize standpoint one can view the farm geospatially from the air selecting field or building locations. The zoom capability in this example allows closer scrutiny of certain building and the selection of one that is of interest. Once done the floor layout of the building is superimposed.
[0111] On entering the building the system allows comprehensive visualization in both 2D, 3D or both depending on which alternative best suits the application. In this example the image shows horses in stalls within the building.
[0112] As with the datacenter example one can monitor and manage information pertaining to the assets, in this case horses. Having established the filtering criteria and being able to see the results for a whole stable, a user can then zoom in on any specific stall or asset as they see fit or navigate around the stable as if one was literally walking the floor to see what assets conform to the query, in this case the horses' age.
[0113] Furthermore all the Report capabilities demonstrated in the earlier example would equally apply in this instance. As a result the system allows the selection from any of the dimensions or measures needed for any enquiry. A list of all the selectable dimensions and measures available appear in scrollable areas on the left hand side of the user interface. Any multiple of these can be selected by a user.
[0114] Finally due to the full integration of all the embodiments of this solution a user can now click on a specific horse and see all its specific information see FIG. 17 .
[0115] 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. 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. | A system for semantically modeling relationships and dependencies between groups, enclosures, assets, and support entities according to an industry specific manner. An exemplary system includes a user interface device, a relational database and a processor. The processor receives relationship information and receives attributes with associated measurements for the groups, enclosures, assets, and support entities for the corporation from the user interface device. The attributes with associated measurements are formatted according the specific industry of the corporation. The processor generates a three dimensional (3D) visualization of the groups, enclosures, assets, and support entities and allows a virtual walkthrough of the 3D visualization as presented on the display device based on user entered commands from the user input device. | 8 |
This is a divisional of copending application Ser. No. 07/892,457 filed on Jun. 2, 1992, now abandoned.
FIELD OF THE INVENTION
The present invention relates to polyvinylidene fluoride ("PVDF") based powder coatings and processes for preparing them. More particularly, it relates to the use of a vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene ("VDF/TFE/HFP") terpolymer in such coatings in order to make an aesthetic, functional coating with a smooth surface.
BACKGROUND OF THE INVENTION
PVDF based coatings (or "paints") have been used and are known to be very good protective coatings for various substrates. They have excellent resistance to weathering and chemical attack.
The traditional method for preparing PVDF based paint has been to formulate a liquid dispersion coating. The liquid vehicle has traditionally been a solvent, but increased environmental laws and regulations have made it more difficult and costly to handle and recover such solvents. Thus, there is a need for solvent-less PVDF based coating systems.
PVDF based powder coatings have traditionally exhibited a certain amount of surface roughness, commonly known as "Orange Peel." This undesirable Orange Peel surface has affected the market acceptance of PVDF based powder coatings as a viable alternative to the liquid, solvent based PVDF coatings.
There are a number of ways which have been tried to reduce the amount of Orange Peel. One is to reduce the melt viscosity of the PVDF resin, but this generally has an adverse effect on the mechanical properties of the coating, such as resistance to impact and flexibility. Another approach, disclosed in European Patent Application 284,996, is to use a coalescing additive which is substantially volatilized from the coating during coalescence; this, however, again introduces the problem of release of solvents. Still another alternative proposed in U.S. Pat. No. 4,770,939 is the incorporation of an acrylic flow modifier, but this is described by the patentee as "not essential."
SUMMARY OF THE INVENTION
A pigmented blend useful for powder coatings is provided comprised of PVDF resin, a thermoplastic acrylic resin, a pigment, and about 0.1 to 5 weight percent, based on the weight of the blend, of a VDF/TFE/HFP terpolymer. Other embodiments of the invention include a process for making a pigmented powder coating composition comprising the steps of blending the foregoing components, pelletizing, and cryogenically grinding, as well as a process of coating a substrate comprising the steps of applying the coating composition on the substrate, heating the composition above its melt temperature, and cooling of the substrate and applied coating composition.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that incorporation of a small percentage of a VDF/TFE/HFP terpolymer into a blend of PVDF resin, compatible thermoplastic acrylic resin, and pigment results in a coating that has fewer defects (craters and poc marks) and a smoother appearance.
The term PVDF refers not only to the homopolymer of VDF but also to the copolymers prepared from at least about 85% by weight of VDF monomer. Co-monomers may include other fluorinated monomers such as TFE, HFP, and vinyl fluoride. The homopolymer is preferred.
The PVDF resins that are preferred are those with a melt viscosity (according to ASTM D3835) in the range of about 6,000 to 13,000 poise at 232 degrees Centigrade, preferably 6,000 to 8,000 poise, a melt flow index (ASTM D1238) of about 20 to 35 g/20 min. at 3.8 Kg and 230 degrees Centigrade, and a melt point between about 165 and 172 degrees Centigrade. A PVDF resin having a melt viscosity above 13,000 poise tends to be too viscous.
A thermoplastic acrylic resin is a necessary component in the formulation as it acts as a stabilizer and provides other desirable coating characteristics such as less discoloration after baking, less discoloration after exposure to high temperature use conditions, and improved post forming durability. Useful acrylic resins include polymers and copolymers of acrylic acid, methacrylic acid, or esters of these acids. The esters are formed by the reaction of acrylic or methacrylic acid with suitable alcohols, such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, and 2-ethylhexyl alcohol. A preferred acrylic resin is a copolymer of methyl methacrylate and ethyl acrylate, such as ACRYLOID B-44 available from the Rohm & Haas Company.
The PVDF/acrylic resin blend makes up about 60 to 95 percent by weight of the overall coating composition, preferably about 82 to 89%. The weight ratio of PVDF to acrylic can range from about 50:50 to 90:10, more typically 60:40 to 80:20.
The pigment component is made up of at least one pigment. Pigments that have been found useful are those that have been used in PVDF based liquid (water or solvent) coatings. The pigments may be organic or inorganic, but inorganic are preferred due to their resistance to ultraviolet and thermal degradation. For white coatings, a non-chalking, non-yellowing rutile type titanium dioxide is preferred, such as du Pont's TI-PURE R-960. For other colors, calcined ceramic metal oxide type pigments are useful. Other pigments useful in combination with titanium dioxide include zinc oxide, zinc sulfide, zirconium oxide, white lead, carbon black, lead chromate, calcium carbonate, and leafing and non-leafing metallic pigments. Pigments that are not recommended include cadmiums and lithopones.
The pigment component must be sufficiently present, generally in the range of about 5 to 35 weight percent based on the weight of the coating composition, in order to provide adequate opacity and hiding power. The preferred range is about 10 to 15%. For light colors and those which contain titanium dioxide, the amount may be as high as 35%.
The component discovered to be essential to solve the Orange Peel problem is the fluorinated terpolymer, VDF/TFE/HFP, which is present at a level of from about 0.1 to about 5.0 weight percent, based on the weight of the coating composition, preferably 1-3%. The terpolymer preferably has a melt point between about 85 and 95 degrees Centigrade and a melt viscosity of from about 4000 to 10,000 poise at 125 degrees Centigrade (ASTM D3835). The use of this terpolymer has been found to result in a decrease in surface roughness, defects, pin holes, and craters in the final coating.
The powder coating formulation is prepared by mixing the PVDF resin, thermoplastic acrylic, pigment, and terpolymer, pelletizing the mixture to form pellets, and cryogenically grinding the pellets to form a powder particulate. Thus, the formulation blend is typically melt mixed, such as by extrusion with a twin screw extruder operating at a temperature of about 390 to 420 degrees Fahrenheit. The extruded material is then pelletized by conventional techniques. The dimension of the pellet is not critical, but it is preferred that it be uniform and small enough to facilitate handling. The pellets are cryogenically ground into a powder particulate according to conventional techniques. For example, the temperature of the pellets may be lowered for grinding by immersion in liquid nitrogen and the grinding equipment may consist of a hammer mill with a 0.010 inch slotted screen, resulting in a particle size range of about 1 to 70 microns. Liquid nitrogen may be fed into the hammer mill during grinding. The resultant powder can be classified by passing through appropriately sized sieves to separate the desired particles (the desired particle size depends upon the application technique). The particles from 1-10 microns are generally discarded for health reasons.
A target coating thickness is typically 2 mils. To achieve this, the powder is ground and classified to an average particle diameter of about 35 to 45 microns. This average particle diameter range will be adjusted upward or downward for thicker or thinner desired coatings, respectively.
The classified powder may be applied to a substrate such as aluminum by any means suitable for obtaining an even distribution of powder. There are a number of conventional techniques which may be used, such as fluidized bed, thermal spray, or, preferably, electrostatic spray. The powder coating may be applied over the substrate with or without a primer coating. After application of the powder, the coating is subjected to treatment which is sufficient to melt a portion of the powder. Thus, the temperature must be above the melt temperature of the coating formulation, preferably between about 460 and 500 degrees Fahrenheit. The coating and the substrate are then cooled by suitable means.
The practice of the invention is illustrated in the following examples. In these examples, unless otherwise indicated, all percents are weight percent, all temperatures are Centigrade, WALNUT BROWN #10 is a brown pigment available from Shepherd Color Co., BLACK 1D is a pigment comprised of oxides of copper and chromium available from Shepherd Color Co., ACRYLOID B44 is a thermoplastic poly(methylmethacrylate)resin which is a copolymer comprised of 70:30 methyl methacrylate and ethyl acrylate with an approximate molecular weight of 88,000 available from the Rohm & Haas Co., KYNAR 710 is a PVDF polymer having a melt viscosity of 6300 poise available from Elf Atochem North America, Inc., and KYNAR ADS is a VDF/TFE/HFP terpolymer with a melt point of about 90 degrees and a melt viscosity of about 6000 poise available from Elf Atochem North America, Inc.
EXAMPLE 1
59.5% KYNAR 710 resin was added to 25.5% ACRYLOID B44, 12% WALNUT BROWN #10, and 3% KYNAR ADS. The mixture was blended in a high intensity mixer until a homogeneous blend was obtained. The batch was then melt-compounded on a two roll mill operating at a temperature of 200 degrees and granulated into pellets. The pellets were soaked in liquid nitrogen and cryogenically ground in a hammer mill equipped with a 0.010 inch slotted screen. Liquid nitrogen was fed into the hammer mill during the grinding operation. The resultant powder was then classified using sieves and the powder which passed through 75 micron screen was collected as useful material. This powder was then electrostatically applied to an alodine pretreated aluminum panel. The panel was baked for 15 minutes at 464 degrees (Fahrenheit). The final coating thickness was approximately 2 to 2.7 mils. The resultant coating was smooth and free from poc marks and craters upon observation at 10X magnification.
EXAMPLE 2
The procedure of Example 1 was followed except that the composition was changed to 60.9% KYNAR 710, 26.1% ACRYLOID B44, 12% BLACK 1D, and 1% KYNAR ADS. Again the resultant coating was free of surface defects, poc marks, and craters, and had a smooth surface.
EXAMPLES 3-4 AND COMPARATIVE RUNS A AND B
Example 1 was repeated with the level of KYNAR ADS at 1% (Example 3) and 0% (Run A). Example 2 was repeated with the level of KYNAR ADS at 3% (Example 4) and 0% (Run B). In all cases the coatings with KYNAR ADS had a better surface appearance than those without ADS, the latter having craters and poc marks down to the bare metal. All samples, with and without KYNAR ADS, passed adhesion, direct impact, reverse impact, and solvent resistance tests. | A process of coating a substrate such as aluminum by the steps of (a) applying thereon a powder coating composition prepared by (i) blending a mix containing a poly(vinylidene fluoride) resin, a thermoplastic resin, a pigment, and a vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene terpolymer, (ii) pelletizing the blend from (i), and (iii) cryogenically grinding the pellets from (ii); (b) heating the powder coating composition above its melt temperature; and (c) cooling the coated substrate. | 8 |
CROSS-REFERENCES TO RELATED APPLICATIONS
The present application claims benefit of U.S. patent application Ser. No. 09/529,144 filed Apr. 7, 2000, which is the U.S. national phase under 35 U.S.C. 371 of International Application No. PCT/EP99/05455 filed Jul. 30, 1999 claiming priority of Swiss Patent Application No. 1645/98 filed Aug. 7, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to medical devices with a surface exposed in particular to the surrounding environment, and in particular a microscope, preferably a surgical microscope and/or its support. Explicitly not comprised in the invention are non-optical instruments for invasive interventions. Included, on the other hand, are optical devices and instruments like, for example endoscopes, laser scalpels, etc., scalpels or medical implants, plastic heart valves or similar items.
2. Description of the Related Art
It has always been a goal during operations and/or in the area of medical research to work in as sterile a manner as possible. That means the patient to be operated on and/or the subject involved in research is as much as possible not to be contaminated by germs (bacteria, viruses, fungi, etc.). Moreover, by completely preventing or removing any impurities, in particular protein substances, allergic reactions by the patient can be prevented, should he accidentally or unprotectedly come into contact with the medical devices. This is normally achieved by meticulously cleaning or sterilizing the surfaces of the medical devices. Those surfaces that do not sterilize well are covered with sterile cloths or sheets. With the operating microscope a “drape” typically must completely envelop or screen the surface of the microscope and support, at least in the sterile area around the patient. A drape of this kind is described, for example, in the German patent specification DE-A1-44 13 920. The drape is as a rule a disposable article so that using it is also connected with costs and with a direct environmental impact. The disposal of disposable articles from an operating room is expensive.
Aside from the fact that the covering and sterilization of the contaminated material, not to mention its disposal, is a time-consuming and costly process, there is always the danger of remaining unsterile gaps. Moreover, drapes as a rule reduce the optical qualities of microscopes, since they necessarily also enclose the lens along with the other parts. The cover glasses used for this can only be poorly steam-sterilized. Moreover, the covers restrict freedom of movement and visibility in the sterile area.
Olympus has brought microscope models CHK2 and CHL2 on the market, the optical parts of which are continually overflowed during manufacture with a thin vaporous antifungal gas that effectively prevents the growth of funguses for a period of three years. A tightly sealed binocular body is even more extensively protected against the onset of fungus because neither impurities nor moisture can intrude into the microscope. This antifungal arrangement involves a protection of the optical parts since fungus often leads to damage of the optical parts of a microscope, especially in tropical regions. In this respect the antifungal coating of the lens provided by Olympus is an improvement, but the sterility of the microscope is not improved. Only the service life of the lens or its optical characteristics are extended. The protection of patients was not within the purview of the producer for this type of antifungal outfitting.
BRIEF SUMMARY OF THE INVENTION
Pursuant to efforts to simplify and increase sterility, the object of the invention is to find measures for simplifying or improving the cleaning and/or the sterility of medical devices.
The object of the invention is fulfilled by applying the features of claim 1 .
Coverings can be done away with and safety can be further increased even under sterile conditions by a special design and/or coating of the surface or material of the medical devices so that said surface or material has a germ-repellent or dirt-repellent effect.
Germ-repellent coatings are already known specifically in the area of medical implants, such as synthetic heart valves, prostheses, etc., but no one has yet publically contemplated using these measures known per se also on medical devices, in particular microscopes and their supports, where the above required or described effects according to the invention are produced.
Preferred additional embodiments of the invention or variants of these additional embodiments are described, or placed under patent protection, in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a magnified perspective view showing an example of a surface formed according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
By employing a germ/dirt-repellent and/or germicidal surface of the medical devices modified according to the invention, the danger of contamination and/or the danger of allergic reaction is reduced, should there be any contact between the surface of the device and the patient.
In addition the cleaning of the devices, especially the lens, is made substantially easier. Also advantageous here is an antiseptic surface or material composition as well as, additionally or alternatively, a surface that is generally dirt-repellent. Falling under the term “dirt” here are all contaminations of the surface by germ infestation and/or by aseptic materials and substances—such as water, fat, protein, etc.
One possibility for the production and selection of materials, in particular with optical glasses and or plastics, including the protective glass/plastic of microscopes is the doping according to the invention of said glasses/plastics with metals or metallic salts, in particular heavy metallic salts, such as silver or copper, zinc, nickel, manganese, cadmium, platinum salts or even, for example, salts of semi-metals, such as boron salts or similar items that—as known per se—act in particular as bactericides, fungicides and virocides. The effect involved here is often produced by metal ions, for example silver ions that can be given off against the germs.
Also the structure of the surface of materials such as housings, supports and in particular of optic glasses/plastics can be formed so as to offer as little support as possible to any kind of adhesive or cohesive forces on the part of septic or aseptic impurities and/or liquids. A fungistatic or fungicidal formation is therefore also advantageous for optical components in the interior of the microscope—as known per se—for example for use in the tropics. A dirt-repellent design is also advantageous here for protection of optical quality when it comes to optical components in the interior of the microscope. As a variant of this, the optical glass/plastic parts could also be coated—e.g. by vapor-deposition—with a very thin coating of a transparent plastic or ceramic material. Also materials from microsystem technology such as silicium, metal-ceramics, metals and plastics such as TEFLON® (polytetrafluoroethylene or PTFE)/silicone, etc. come into play here.
To increase the rigidity and toughness, there are high-density ceramics as microscope chassis known per se according to EP-B1-90967. A reference to the object of the invention presented in the preamble cannot be inferred from it.
The coating of parts with specific substances is known in principle, as for example:
color like coating to produce a pleasant appearance, such as hammer dimple enamel coating to increase surface strength;
coating with anti-oxidants and light stabilizers, e.g. as described in EP-A1-745 646;
coating of a lens support with synthetic polymers for bio-processes, e.g. as described in U.S. Pat. No. 4,357,142;
chroming of surfaces to increase surface strength, etc.
TEFLON® coated lenses, or lens housings are also known per se, but these known coated lenses were developed for other purposes, including lenses for inversion microscopes that can be immersed in Petri dishes and thus come into contact with liquid media. The TEFLON® coating applied in that case has essentially three purposes:
1. To inhibit mechanical abrasion (scratch-proofing) of the lens
2. To give the lens an increased resistance to corrosion
3. To prevent any metal ions of the lens housing from migrating into the liquid medium through a chemical-physical process (chemical protection of the medium from the lens being immersed).
Aside from the fact that the hydrophobic property of TEFLON® was naturally accepted as a welcome feature, this becomes obvious for the type of the liquid media. The technique by which the inversion microscope of this type came into use was named among other things the “patch-clamp technique.”
However, a coating for the purposes indicated in the preamble for medical devices has never yet been suggested.
In the use of ceramics as per the invention, sintered ceramics and/or metal ceramics are contemplated, their surface being formed such that it is germ and/or dirt-repellent. One skilled in the art thus has to take into consideration certain geometric dimensions that have more favorable or unfavorable characteristics for corrosion by septic or aseptic impurities. Although every microstructure must have a certain structure, it will appear to the observer as a “smooth surface” to which nothing sticks. Metal ceramics, Al 2 O 3 and AIN are best suited for a vapor deposition according to the invention.
One skilled in the art can thus select from a filling of ceramic materials that are known per se, this including in principle also modern materials such as glass metals with an alloy containing nickel, zircon and titanium. The atoms of such glass metals have not formed a regular crystal lattice. They are arranged randomly, resulting in an amorphous structure. C/SiC-bonded ceramics, as are used for example for mirror structures, can also come into use as oxide ceramics.
In a special surface formation according to the invention—primarily also for ceramic surfaces—the following principle is employed: The surface is physically (e.g. chemically and/or micro-mechanically) structured such that undesirable substances cannot adhere. A possible configuration thus provides the intentional arrangement of elevations with specific geometric dimensions that offer substances (e.g. liquids) no support on the surface due to their surface tension. The substances therefore cannot exert any adhesive forces on the surface.
Comparable effects are known in nature, e.g. in the natural surface formation of lotus leaves (surface structure) or on alchemilla conjuncta leaves (coated with very fine fuzz) on which water beads up without dampening the leaf when picking up any kind of adjacent dirt particles.
Aside from the prevention of adhesion, these surfaces are also especially easy to clean, since due to the adhesive forces of cleaning fluids—which themselves cannot react with the surface—dirt particles that might be lying on the surface are bonded to the drops of cleaning fluid and thereby rinsed away.
A surface with the following geometric structure is indicated as an example of such a surface structure (in some cases it does not have to be in a mathematically exact configuration):
Sin(x)×Cos(y).
The resulting surface has a regular mound structure, the peaks of which preferably have the following interval: 1-100 μm, in particular 3-60 μm.
Alternatively, the elevations can also have a cubic or conical structure.
The invention nevertheless also encompasses mixed forms that one skilled in the art can determine in routine experiments.
The effectiveness of such surfaces formed according to the invention can be strengthened by combination with other measures according to the invention, such as a germicidal dressing (e.g. metal or metallic salt coating).
A particular embodiment is attained by making the micro-mechanical elevations out of various elements (especially metals or half metals), which in some cases are electrically isolated from one another, so that in addition to the mechanical and biocidal characteristics of the corresponding metals, there are also electrical or electrolytic effects that have an especially toxic or repellent action for particular germs.
Another possibility for treating standard devices, in particular supports, according to the invention is coating them with the matrix of a carrier material in which germicidal or germ-repellent substances are incorporated. Falling under germicidal substances here are all of those substances that have been traditionally used or will be used in the future to kill germs or to disinfect. These can be the aforesaid metallic salt compounds, but can also be alcohols, oxidizing materials, cell-membrane-damaging polyelectrolytes—e.g. tenside, etc.—or mixtures thereof.
This configuration according to the invention stands to a certain degree in contrary juxtaposition to the coatings according to the above-mentioned EP-A1-745 646.
“Supporting materials” are to be understood here as all of those materials that are suited to absorb other materials, namely germicidal substances. These can be foams or fabrics or other structures in which the said substances can be incorporated, integrated or attached. In the broadest sense, the matrix of the supporting material can also be constituted such that it supports on its surface germicidal substances, germ-repellent substances and the like. Consequently, such supporting materials can be constituted of plastic, rubber, lacquers, ceramics, etc. For example, this can also be an anti-fouling lacquer, which even today has germ-repellent and marine-plant-repellent properties, e.g. in boat construction.
Another idea, independent in and of itself, which can nevertheless be logically applied by itself or in combination with the previously mentioned ideas according to the invention, is to configure the surface or parts thereof—e.g. underlying parts—as electrically conductive. This is, on the one hand, so that the surface can thereby be configured as anti-static and, on the other hand, the surface can also, through the principle of resistance, be artificially brought to a germicidal temperature that kills at least heat-labile germs. In the electrostatic treatment of a surface according to the invention, there are several different factors to take into account, in particular the voltage ratios or electrostatic charging ratios in the surrounding environment. To attain electrical, electro-thermal or electrostatic characteristics, conductive material, e.g. carbon, can be integrated into the surface. Due to their antitoxicity, activated carbons with larger inner surface areas can possibly be used.
The anti-electrostatic coating of microscopes has been published in a patent by the applicant, e.g. in WO-A1-95/19583. Different microscopes, such as the LEICA MS5, MZ6 and MZ8 are on the market in the “ESD (electrostatic discharge) version.” However, the object of the present invention is not resolved by this known anti-static coating, even if—by chance—the antistatic coating provided for the protection of electronic components also leads to a reduction of dust and dirt deposits on the devices. However, the contact sterility is still not fundamentally improved by this.
In another area, a retroreflector has already been treated by the applicant with a conductive coating for another purpose, namely heating up its surface to prevent the accumulation of ice and vapor condensation. See WO-A1-96/33428. A germicidal action was not yet provided for this.
In the use of the conductive resistance coating according to the invention, attention must be paid to the temperature stability of the supporting material. The purposive use of e.g. polymers with filler materials that increase thermal deformation resistance, for example mica, is suggested for this. A comprehensive article on various filler materials is indicated in “Kunststoffe [Plastics] 87 (1997) 9, Carl Hanser Verlag, Munich, pp. 1106-1112”, which makes explicit reference to this.
The preferred application of various elements is placed under protection in claim 14 .
The invention is not restricted to the individual inventive elements; on the contrary a combination of the same can produce symbiotic effects, i.e. antiseptic or germ/dirt-repellent effects.
For the purposes of this invention, “lens” is to be understood here as including all optical components such as glasses, plastics and also mirrors, which can be made of metal.
An example of a surface according to the invention is depicted in the drawing.
This shows as an example a sinusoidal/cosinusoidal-form surface with homogeneous elevations and indentations. A surface is formed as a function of the measures between the elevations so as to repel adhesive forces, or prevent the attachment and clogging of germs in a purely mechanical way. However, within the framework of the invention, one could also dispense with the downward-protruding valleys.
The elevations and valleys are drawn with grid lines for better visual representation.
Within the framework of the invention, there are also particular embodiments in which the elevations or valleys are constituted of different materials such that adjacent elevations are different, or such that parts of elevations differ. Thus, different materials are conceivable, especially various metals, along specific grid lines or along elevation lines (not shown), for example.
If the metals are isolated from each other, this results in electrolytic processes for ion-conductive substances coming into contact with said metals. The ion-conductive processes can furthermore have an anti-septic action. | The invention relates to a medical apparatus having a special coating on its surface, notably its surface facing the surroundings. The coating has germ and/or dirt-repellant and/or bactericidal properties. Special embodiments of the invention include dirt and/or germ-repellant and/or antiseptic materials or surface structures and anti-electro-static and/or electrically heated materials. | 0 |
FIELD OF THE INVENTION
[0001] The present invention generally relates to hardware emulators, and more particularly to monitoring physical parameters in a hardware emulator.
BACKGROUND
[0002] Today's sophisticated SoC (System on Chip) designs are rapidly evolving and nearly doubling in size with each generation. Indeed, complex designs have nearly exceeded 50 million gates. This complexity, combined with the use of devices in industrial and mission-critical products, has made complete design verification an essential element in the semiconductor development cycle. Ultimately, this means that every chip designer, system integrator, and application software developer must focus on design verification.
[0003] Hardware emulation provides an effective way to increase verification productivity, speed up time-to-market, and deliver greater confidence in the final SoC product. Even though individual intellectual property blocks may be exhaustively verified, previously undetected problems appear when the blocks are integrated within the system. Comprehensive system-level verification, as provided by hardware emulation, tests overall system functionality, IP subsystem integrity, specification errors, block-to-block interfaces, boundary cases, and asynchronous clock domain crossings. Although design reuse, intellectual property, and high-performance tools all help by shortening SoC design time, they do not diminish the system verification bottleneck, which consumes 60-70% of the design cycle. As a result, designers can implement a number of system verification strategies in a complementary methodology including software simulation, simulation acceleration, hardware emulation, and rapid prototyping. But, for system-level verification, hardware emulation remains a favorable choice due to superior performance, visibility, flexibility, and accuracy.
[0004] A short history of hardware emulation is useful for understanding the emulation environment. Initially, software programs would read a circuit design file and simulate the electrical performance of the circuit very slowly. To speed up the process, special computers were designed to run simulators as fast as possible. IBM's Yorktown “simulator” was the earliest (1982) successful example of this—it used multiple processors running in parallel to run the simulation. Each processor was programmed to mimic a logical operation of the circuit for each cycle and may be reprogrammed in subsequent cycles to mimic a different logical operation. This hardware ‘simulator’ was faster than the current software simulators, but far slower than the end-product ICs. When Field Programmable Gate Arrays (FPGAs) became available in the mid-80's, circuit designers conceived of networking hundreds of FPGAs together in order to map their circuit design onto the FPGAs and the entire FPGA network would mimic, or emulate, the entire circuit. In the early 90's the term “emulation” was used to distinguish reprogrammable hardware that took the form of the design under test (DUT) versus a general purpose computer (or work station) running a software simulation program.
[0005] Soon, variations appeared. Custom FPGAs were designed for hardware emulation that included on-chip memory (for DUT memory as well as for debugging), special routing for outputting internal signals, and for efficient networking between logic elements. Another variation used custom IC chips with networked single bit processors (so-called processor based emulation) that processed in parallel and usually assumed a different logic function every cycle.
[0006] Physically, a hardware emulator resembles a large server. Racks of large printed circuit boards are connected by backplanes in ways that most facilitate a particular network configuration. A workstation connects to the hardware emulator for control, input, and output.
[0007] Before the emulator can emulate a DUT, the DUT design must be compiled. That is, the DUT's logic must be converted (synthesized) into code that can program the hardware emulator's logic elements (whether they be processors or FPGAs). Also, the DUT's interconnections must be synthesized into a suitable network that can be programmed into the hardware emulator. The compilation is highly emulator specific and can be time consuming.
[0008] There are many different physical parameters associated with an emulator environment, such as which board types are plugged into the emulator and where they are plugged in, what are the temperatures on the boards, what are the board failure rates, etc. Prior to compiling a design and trying to run it in an emulator, such physical parameters are helpful to have an understanding if the emulator can accept and emulate the design. Yet, there is not a known way to view such physical parameters in an effective manner. Particularly, there is not known a way to view such physical parameters in real time in a graphical user interface while the emulator is emulating a design.
[0009] Thus, it is desirable to provide an emulator environment with the ability to view physical parameters associated with the emulator.
SUMMARY
[0010] The present invention provides a method and system for monitoring and viewing physical parameters while the emulator is emulating a design. Additionally, the parameters are in real time or substantially real time, such as after a periodic update.
[0011] In one embodiment, a monitoring portion of the emulator periodically monitors the emulator boards and power supplies for physical information. The physical information is communicated to a workstation for communication to a user. For example, the workstation can display the physical information in a graphical user interface (GUI) that shows which boards are plugged in the system and which slots are empty.
[0012] In yet another aspect, the user can select a particular board in the system using the GUI and view communication information, such as data errors, status, link errors, global errors, etc.
[0013] In a further aspect, power supply information can be viewed, such as current and voltage levels, air temperature, fan speed, board temperatures at particular points, etc.
[0014] In another aspect, the IC layout on a board can be viewed with a graphical presentation of which ICs are malfunctioning. Even further, the sections within a particular IC can be viewed with a graphical presentation of sections within the IC that are malfunctioning.
[0015] These features and others of the described embodiments will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a system diagram of a hardware emulator environment according to the invention.
[0017] FIG. 2 is a more detailed system diagram showing multiple host computers coupled to the emulator through an intermediate platform maintenance board.
[0018] FIG. 3 is a high-level system diagram showing various servers connected through a messaging bus.
[0019] FIG. 4 is a three-dimensional physical view of a system of FIG. 1 .
[0020] FIGS. 5A-5C show a GUI with different physical views of the actual system of FIG. 4 .
[0021] FIGS. 6A and 6B show the GUI displaying error rates of various boards in the system.
[0022] FIGS. 7A-7D show power and temperature information associated with the system using a GUI.
[0023] FIGS. 8A and 8B show a logical representation of an internal portion of an IC and a physical view of a printed circuit board using the GUI.
[0024] FIGS. 9A and 9B show particular registers of the system accessed through the GUI.
[0025] FIG. 10 is a flowchart of a method for monitoring and displaying physical parameters in the system.
DETAILED DESCRIPTION
[0026] FIG. 1 shows an emulator environment 10 including a hardware emulator 12 coupled to one or more hardware emulator hosts 14 . The emulator host 14 may be any desired type of computer hardware and generally includes a user interface through which a user can load, compile and download a design to the emulator 12 . Additionally, the user can visualize physical parameters associated with the emulator through a graphical user interface (GUI) on any of the emulator hosts 14 , as further described below.
[0027] The emulator 12 includes a monitoring portion 16 and an emulation portion 18 . The emulation portion 18 includes multiple printed circuit boards 20 coupled to a midplane 22 . The midplane 22 allows physical connection of the printed circuit boards into the emulator 12 on both sides of the midplane. A backplane may also be used in place of the midplane, the backplane allowing connection of printed circuit boards on one side of the backplane. Any desired type of printed circuit boards may be used. For example, programmable boards 24 generally include an array of FPGAs, VLSIs or ICs, or other programmable circuitry, that may be programmed with the user's design downloaded from the emulator host 14 . One or more I/O boards interface 26 allow communication between the emulator 12 and hardware external to the emulator. For example, the user may have a preexisting processor board that is used in conjunction with the emulator and such a processor board connects to the emulator through I/O board interface 26 . Clock board 28 generates any number of desired clock signals. And interconnect boards 30 allow integrated circuits on the programmable boards 24 to communicate together and with integrated circuits on the I/O board interface 26 .
[0028] FIG. 2 shows a more detailed view of the system. The multiple host computers 14 are coupled together through a network 40 , such as a LAN, but other networks can also be used. The host computers 14 are equipped with a high-speed-link PCI board coupled to a platform maintenance board (PMB) 42 , which acts as the monitoring portion 16 . The PMB 42 monitors various physical parameters in the emulator portion 18 as well as creates the interface between the emulator portion 18 and the host computers 14 . The PMB 42 on a periodic basis (e.g., 10 seconds) transmits communication and monitoring reports to the host workstations 14 for display in the GUI. Similarly, the PMB 42 may receive information regarding the physical parameters of the emulator portion 18 periodically. For example, hardware (e.g., an FPGA) on each printed circuit board 20 has intelligence for monitoring physical parameters on its respective board and for sending this physical information to the PMB (e.g., every 5 seconds). Other changes, such as a detected error, are transmitted immediately upon and in response to the detection. Thus, the PMB 42 may instantaneously (as opposed to periodically) detect any changes in the emulation environment 10 and generate real-time state change messages to the host stations 14 . All of the physical parameters obtained through the PMB may be obtained while the emulator portion 18 is performing emulation. Thus, several emulations may be separately running and the physical parameters of the emulator may separately be viewed on the GUI of the host computers. However, there need not be a link between the number of simultaneous emulations and the number of workstations. For example, many emulations can be simultaneously run through one workstation. The printed circuit boards 20 are grouped in a one-to-one correspondence with the number of host computers. This grouping allows one host computer to be associated with a group of boards 20 so that multiple high-speed links can be used in parallel. Obviously, the grouping used is a design choice and may easily be modified based on the design or not used at all. IO boxes 46 allow connection of other user boards to the system. The IO boxes 46 are also coupled to the PMB 42 and monitored thereby.
[0029] FIG. 3 shows a view of the emulator system including various servers 60 that communicate through a messaging bus 62 . Emulator servers 64 are in charge of managing one physical host connection to the emulator and provide a way to transfer data between the emulator messaging bus 62 and the emulator 12 . The maintenance server 66 is in charge of diagnostics, and storing maintenance information collected from other applications, servers, and/or emulator boards. The maintenance server also interacts with the GUI to display the information to the user. The resource server 68 is in charge of managing the different emulator resources provided to the applications.
[0030] FIG. 4 shows a physical three-dimensional view of the emulator portion 18 including the midplane 22 having horizontal boards 80 coupled to one side of the midplane, and vertical boards 82 coupled to the opposite side of the midplane. The physical integrated circuits are shown at 84 . The IO boxes 46 sit separately and are not generally considered part of the emulator.
[0031] FIG. 5A shows a window 100 of the GUI displayed on any of the computers 14 or accessible from the computers 14 . The window 100 has an emulation information panel 102 and a physical system view panel 104 . The emulation information panel 102 provides a summary of the number of boards in the system that are operational and provides the board types. For example, the panel 102 lists that nine AVB boards are operational and one CXB board is available. AVB is a board type that includes programmable FPGAs, VLSI, or ICs used for programming the user's design (see FIG. 1 at 24 ) whereas the CXB board is a board that generates the system clocks (see FIG. 1 at 28 ). Other boards are also listed, such as the SXB boards (switching matrices)(see FIG. 1 at 30 ), the SIOB boards (I/O board interface)(see FIG. 1 at 26 ) and the IO boxes 46 . In panel 104 , three tabs 106 provide different physical views of the system, including a top view, side view and IO view. The top view tab is selected in FIG. 5A and shows a physical view of the boards of FIG. 4 . Only the top-most board of the horizontal boards 80 can be seen, while all of the vertical boards 82 are shown. The midplane 22 is shown having numbers 0 - 15 representing each available AVB slot for the vertical boards 82 , plus 0 - 1 representing SIOB slots for the vertical boards 82 . The darkened slots represents the boards physically positioned in the slots, while the white boxes, shown at 108 , represent empty slots. The physically present boards may also be shown in different colors (not shown) to represent whether the board is correctly operating or has a malfunction.
[0032] FIG. 5B shows the same window 100 with the side view tab 106 selected. In this view, the physical boards of the system shown in FIG. 4 are seen from the side view. In this case, only one vertical board 82 in slot 0 is visible, while the horizontal boards 80 are displayed including indicia 110 to indicate the board type.
[0033] Thus, from FIGS. 5A and 5B , the physical view of the system is shown including board types, their slot positions within the system, and whether or not they are properly functioning. Additionally, both views provide a status line 112 that provides real time physical parameters associated with the system, such as the emulator name (shown as an alpha-numeric string), whether that emulator is operational, the voltage, power, temperature, and the last change in the physical environment that occurred.
[0034] FIG. 5C shows the same window 100 with the IO view tab 106 selected. This view shows two 10 boxes 114 and 116 . IO box 114 is currently shown as operational with six boards plugged in, while IO box 116 is shown having empty slots.
[0035] FIGS. 6A and 6B show different views related to communication information in a window view 130 . Tabs 132 allow the user to select the board type within the system. For example, in FIG. 6A , the tab PMB is selected and panel 134 shows different communication errors associated with the PMB 42 . For example, catastrophic errors, link errors, data errors, packets marked bad errors and global errors. Thus, the physical error information is available for any board.
[0036] FIG. 6B shows the window view 130 with the AVB tab 132 selected. In this view, a drop down window 136 is provided to allow the user to select which AVB board to view. Thus, for any desired AVB, the user can view real time or substantially real time error information. Tabs 132 also include views of other system boards, such as SIOB and the IO Boxes.
[0037] FIGS. 7A through 7D show a window 150 related to monitored data within the system. Thus, other physical parameters associated with the system may be viewed in the GUI in real time. In FIG. 7A , window 150 has tabs 152 including a power status system tab, a consumption tab, a board temperature tab and an IO Box temperature tab. FIG. 7A shows the power status system tab selected and shows information windows 154 that indicate whether the main power is on or off, and the status of various power modules. Different status information shows that module is OK, missing, faulty, partially faulty, etc.
[0038] FIG. 7B shows the consumption tab 152 selected resulting in four panels 156 , 158 , 160 , and 162 being displayed. Panel 156 shows the current voltage consumption and the minimum and maximum voltage consumption. Panel 158 shows the current being consumed and the minimum and maximum current levels used. Panel 160 shows the current air temperature within the emulator as well as the minimum and maximum air temperatures. Panel 162 shows the fans being used in the system and their current percentage of operational capacity. Thus, 80% means the fan can increase another 20% to be at maximum capacity, but increasing fan speed can increase noise and vibration within the system.
[0039] FIG. 7C shows window 150 with the board temperature tab 152 selected. In this window view, five panels are displayed 170 , 172 , 174 , 176 and 178 , each representing a different board type in the system. In panel 170 , a drop down window 180 allows the user to select the particular AVB in the system. Currently, AVB number 3 is shown. Information windows 182 show the various temperatures of preselected points on the board. In this example, each AVB has a preselected hot point and a preselected cold point in which a temperature sensor is positioned. The information windows 182 show the current temperature at each of the hot and cold points as well as the minimum and maximum temperatures at each point. Each of the other panels, 172 , 174 , 176 and 178 have similar functionality for the SIOB, SXB, CXB, and PMB, respectively.
[0040] FIG. 7D shows window 150 with the IO Box temperature points tab 152 selected. In this case, two panes 184 and 186 are shown, each for its respective IO Box. In pane 184 , drop down window 188 allows selection of different UB-type boards in the IO Box, while drop down window 190 allows different TIB-type boards to be selected. Once the desired boards are selected the current hot and cold point temperatures as well as the minimum and maximum temperatures are provided. Similar operation can be performed in pane 186 .
[0041] FIG. 8A shows further physical information associated with the boards within the emulator environment 10 . In particular, FIG. 8A shows a fault editor window 200 that allows the user to visualize a cluster or memory within an IC to determine which areas of the IC have faults. Tabs 202 allow the user to select the board type, and drop-down window 204 allows the user to select the particular board within the system. Drop-down window 206 allows the user to select the particular IC on the board to view whether the clusters and memory areas of the IC are functioning properly. Areas that are not functioning properly are indicated with a different color (not shown), such as red to indicate a problem area and green to indicate proper functionality.
[0042] FIG. 8B shows a window 220 with a physical view of a board in the system. The board view shows various ICs such as at 222 . ICs that are not functioning properly are shown in a different color (not shown). In this way, a user can view physical parameters, such as the functionality of an IC, using the GUI and take corrective action if necessary.
[0043] FIG. 9A includes a resource access window 230 that allows a user to access a particular register on a board in the system and modify the contents of that register using the GUI. For example, window 232 shows a particular register for the chosen board, chip, and block type. FIG. 9B shows a similar window 234 allowing the user to read and modify memory.
[0044] FIG. 10 shows a flowchart 250 of a method for displaying physical parameters within a GUI. In process block 252 , a design is currently being emulated in the emulator. In process block 254 , during the emulation, the monitoring portion of the emulator receives physical parameters associated with the emulation portion of the emulator, such as all of the parameters discussed in the previous Figures. In process block 256 , the physical parameters are displayed in the GUI. Several host computers may be performing emulation within the same emulator environment and simultaneously be able to view the physical parameters associated with the emulator through interconnection with the PMB.
[0045] Having illustrated and described the principles of the illustrated embodiments, it will be apparent to those skilled in the art that the embodiments can be modified in arrangement and detail without departing from such principles.
[0046] It should be recognized that the GUI application can run out of any workstation not just the host workstation.
[0047] In view of the many possible embodiments, it will be recognized that the illustrated embodiments include only examples of the invention and should not be taken as a limitation on the scope of the invention. Rather, the invention is defined by the following claims. We therefore claim as the invention all such embodiments that come within the scope of these claims. | A method and system is disclosed for monitoring and viewing physical parameters while the emulator is emulating a design. Additionally, the parameters are in real time or substantially real time, such as after a periodic update. In one embodiment, a monitoring portion of the emulator periodically monitors the emulator boards and power supplies for physical information. The physical information is communicated to a workstation for communication to a user. For example, the workstation can display the physical information in a graphical user interface (GUI) that shows which boards are plugged in the system and which slots are empty. In yet another aspect, the user can select a particular board in the system and view communication information, such as data errors, status, link errors, global errors, etc. In a further aspect, power supply information can be viewed, such as current and voltage levels, air temperature, fan speed, board temperatures at particular points, etc. In another aspect, the IC layout on a board can be viewed with a graphical presentation of which ICs are malfunctioning. Even further, the sections within a particular IC can be viewed with a graphical presentation of sections within the IC that are malfunctioning. | 6 |
OBJECT OF THE INVENTION
[0001] The present invention relates to a vessel which has been especially designed for collecting oil spills at sea as a consequence of accidents sustained by oil tankers or of other causes, i.e., for collecting what is commonly referred to as “oil slick”.
[0002] The object of the invention is to achieve a vessel that is capable of performing said collecting of oil spills in low-draft areas, as mostly occurs along a wide maritime strip adjacent to the coast, including beaches, ports, rias, and even lakes.
[0003] The invention is therefore comprised in the field of environmental protection, particularly in the elimination and surface collection of contaminating products which float on the water, and more particularly hydrocarbons.
BACKGROUND OF THE INVENTION
[0004] The applicant is the proprietor of Spanish invention patent application number P 200300087, consisting of a device for cleaning up oil spills, intended to be coupled to the hull of a vessel, on each side thereof. More specifically, said device consists of an arm made up of a casing with a configuration tending to a semicylinder, the inside of which houses a screw tending to displace the crude oil towards the hull of the vessel, which casing is stiffened by means of a plurality of rear plates and is open forwards and upwards, the arm having a float at its free end and finished at its free end in a collection tank in which the mentioned screw unloads and in which there is arranged the drive transmission mechanism for same, as well as a tube connected to a suction pump propelling the crude oil towards the collection vessel.
[0005] This device, which can be applied to any conventional vessel having collection tanks with a suitable capacity, offers optimal functional features in terms of the product collection capacity per unit of time.
[0006] However, such device has an important problem derived more from the vessel in which it is coupled than from its own structure, because vessels with a suitable spill storage capacity base their stability, as in most vessels, on the lower keel thereof, which entails a draft of such magnitude that it means that conventional vessels cannot navigate in areas close to the coasts, and even less so in beaches, ports, rias, lakes, etc.
[0007] If the fact that the movement of the water tends to displace spills precisely towards the coasts is taken into account, the severity of the problem set forth is evident.
DESCRIPTION OF THE INVENTION
[0008] The vessel for collecting oil spills proposed by the invention has been designed and structured exclusively for this purpose, and its objective is to achieve a large load capacity while at the same time achieving such a low draft level that it allows its navigation from the high sea to the coast, because said draft depth can be about 50 cm.
[0009] To that end and more specifically, the proposed vessel adopts a T-shaped front transverse segment, said vessel having no keel, i.e., it has a launch-type planar hull base, but with considerably larger dimensions than the latter, said front transverse segment being the segment which, as a result of its considerable width, provides the vessel with due stability during its navigation.
[0010] The Archimedean screw, similar to the one in invention patent P 200300087, is located in the front transverse head or segment of the mentioned T shape, duly opposite an inlet mouth which concerns the entire front face of the head and which converges towards the mentioned Archimedean screw, there being enough space in said head for arranging therein the operating means of the mentioned Archimedean screw, preferably a hydraulic motor, as well as the drive pumps for driving the collected oil spills towards the storage tanks.
[0011] These storage tanks are located on both sides of the body of the vessel, immediately behind the corresponding end areas of the front transverse head, and they have the particularity of being physically independent from the hull of the vessel, whereby being linked through vertical guides immobilizing said containers in the transverse direction, but allowing their mobility in the vertical direction, such that the draft of the containers is virtually nil when they are empty and gradually increases as the load or filling thereof increases, up to a limit situation determined by the depth of the water in the work area.
[0012] The hull of the vessel incorporates on its upper side areas and at the level of its longitudinal body cocks for unloading the spills driven by the mentioned pumps in either of the containers mentioned, or in either of the compartments that said containers can be provided with.
[0013] It must also be pointed out that said containers can easily be separated from the hull of the vessel, such that after the vessel reaches a port it is not necessary to immediately empty the containers, but rather they can be replaced with empty containers so that the vessel can continue working while the full containers are being emptied.
[0014] It must finally be indicated that the front head of the vessel is linked to the longitudinal body thereof through oscillation means which allow sufficiently tilting said head in order to prevent the entrance of water and spills towards the area where the Archimedean screw is located, said head acting through its lower face as a stabilizing means for the vessel, which allows its movement at considerably higher speeds than when it is in the working situation. In any case, the vessel is driven by propulsion equipment with an inboard/outboard system.
[0015] In those cases in which the waste to be collected has a low density, the waste is displaced together with the water in the thrusting exerted by the transverse head on said water, due to the normal forward movement of the vessel, which evidently means that the waste in question will access with certain difficulty the Archimedean screw.
[0016] To solve this problem, it has been provided that in front of the Archimedean screw there is an also transverse shaft that is provided with a plurality of radial blades, such that as a result of the motor-powered operation of this shaft, the blades, with a suitable rotation direction, act on the oil waste by introducing it in the head, i.e., displacing it towards the Archimedean screw, so the efficiency of the vessel in collecting such waste is optimal.
[0017] Evidently, the front transverse head of the vessel will be suitably oversized in order to receive therein the blade-carrying shaft, such that the latter is in turn behind the front inclined planes which favor the access of oil spills to the mentioned head.
[0018] These blades can optionally be provided with, in their majority portion, rectangular windows minimizing both their weight and the amount of material used therein, but without the strength of said windows being a determining factor.
[0019] In any case, the thrust effect of the bow of the vessel on the water, which tends to displace the waste, is compensated by the absorption effect of said waste caused by the rotation of the blade-carrying shaft, whereby the performance of the vessel is optimal, as has been mentioned above.
[0020] The mentioned blade-carrying shaft can have its own motor-powered operation, housed in the hollow interior of the sides of the front head, or it can share the motor-powered operation with the Archimedean screw, without this affecting the essence of the invention.
[0021] Finally, and in an embodiment variant, it has been provided that this blade-carrying shaft and the Archimedean screw itself include rollers for raising the waste so that when the blades rotate, such waste is raised towards the Archimedean screw by means of the mentioned rollers.
DESCRIPTION OF THE DRAWINGS
[0022] To complement the description made below and for the purpose of aiding to better understand the features of the invention according to a preferred practical embodiment thereof, a set of drawings is attached as an integral part of said description in which the following has been depicted with an illustrative and non-limiting character:
[0023] FIG. 1 shows, according to a schematic perspective depiction, a vessel for collecting oil spills carried out according to the object of the present invention, lacking the side containers for receiving the spill.
[0024] FIG. 2 shows a plan view of the assembly depicted in FIG. 1 , in this case the vessel being provided with the mentioned containers for receiving the spill.
[0025] FIG. 3 shows a side elevational view of the vessel of the previous figures.
[0026] FIG. 4 shows a section similar to that of FIG. 3 , but in which the front head of the vessel is in a raised position, inoperative from the collecting point of view.
[0027] FIG. 5 shows a plan view of a detail at the level of one of the coupling guides between the hull of the vessel and the side containers thereof.
[0028] FIG. 6 shows a perspective view of a detail of the front area of the vessel corresponding to a practical embodiment variant of the invention, in which before the Archimedean screw there is a motor-powered shaft provided with a plurality of blades facilitating the collection of the waste.
[0029] FIG. 7 shows a side elevational view of a detail of the assembly of the previous figure.
[0030] FIG. 8 shows a plan view of what has been depicted in the previous figure.
[0031] FIG. 9 finally shows a side elevational view of FIG. 6 , but in this case arranging between the assembly of blades and the Archimedean screw a band of rollers for raising the waste towards the Archimedean screw itself.
PREFERRED EMBODIMENT OF THE INVENTION
[0032] In view of the discussed figures, it can be observed how the proposed vessel is formed from a considerably elongated hull ( 1 ) with a planar base, i.e., having no keel, at the front end of which there is coupled a transversely elongated head ( 3 ) conferring to the vessel in its assembly a T-shaped hull, there being located in the central area of said head ( 3 ) an Archimedean screw ( 4 ), like the one in the aforementioned invention patent, towards which screw the floating spills access through inclined planes ( 5 ), this head ( 3 ) having covers or manholes ( 6 ) for accessing its interior, in which both the operating means of the Archimedean screw ( 4 ) and the pumps ( 7 - 8 ) for driving the spills towards the collection tanks ( 9 - 9 ′) for said spills are arranged.
[0033] As is particularly observed in FIG. 2 , the mentioned tanks or containers ( 9 - 9 ′) for collecting the spill take up the spaces defined behind the head ( 3 ) and on both sides of the central body ( 1 ) of the vessel, converting the mentioned T shape thereof into a rectangular shape, and in which, according to a preferred embodiment of the invention, the draft of said body ( 1 ) is of the order of 50 cm, whereas the draft of the containers ( 9 - 9 ′) is variable, as will be explained below, the vessel having a total girder of 14 meters, a maximum breadth of 9 meters, a collection capacity maximum of the order of 102 m 3 (approximately 100 tons depending on the density of the collected product), and the movement of the vessel is carried out, as previously mentioned, by means of propulsion equipment with an inboard/outboard system equipped with two injection motors ( 10 - 10 ′) having 160 horsepower each, whereas for supplying the motors of the pumps ( 7 - 8 ) and of the Archimedean screw ( 4 ), the vessel incorporates a diesel motor ( 11 ) having 158 horsepower at 1,800 rpm, with emergency stop, alarm, tachometer, horometer and start-up switchboard, as well as with a gear box with coupling for the pumps, and tanks for hydraulic oil and fuel.
[0034] The vessel is complemented with a control post provided with the operating control instruments for the motors and the navigation and safety instruments, suited to the navigation particularities of these vessels.
[0035] Returning again to the tanks or containers ( 9 - 9 ′), the latter receive the spilled hydrocarbons collected by the Archimedean screw ( 4 ) through cocks ( 12 ) distributed along the upper side areas of the elongated body ( 1 ) of the vessel, which body in its side walls incorporates at least one pair of vertical guides ( 13 ), one of which is depicted in detail in FIG. 5 , which guides ( 13 ) are intended to receive respective complementary guides ( 14 ) duly integral with or fixed to the inner side wall of the containers ( 9 - 9 ′), with the particularity that each guide ( 13 ) of the body ( 1 ) of the vessel is defined by the body ( 1 ) itself and by an oscillating section ( 15 ) that can turn on a vertical shaft ( 16 ), such that depending on the position adopted by said section ( 15 ) the floats ( 9 - 9 ′) are immobilized with respect to the hull of the vessel in the transverse direction, but with the possibility of displacement in the vertical direction, or they are released for their transport towards the area for emptying them.
[0036] These guides ( 13 - 14 ) allow the draft of said containers to range between 0.1 and 1.5 meters, depending on the load stored therein. In terms of transferring the containers ( 9 - 9 ′) to the spill area, this can be done by towing them with small vessels or with helicopters, nevertheless the vessel itself could perform this displacement, which is not advisable given that the collecting efficiency is thereby reduced.
[0037] In any case and as is observed in FIG. 4 , the front transverse head ( 3 ) is attached in an articulated manner to the longitudinal body ( 1 ) forming the hull of the vessel, for example through a robust hinge ( 17 ), such that with the collaboration of a pair of hydraulic cylinders ( 18 ), the head ( 3 ) can go from the working position shown in FIG. 3 to the inoperative position shown in FIG. 4 , where access to the Archimedean screw ( 4 ) is temporarily blocked, allowing greater speed for the vessel when it heads towards the work area, when it displaces the full containers towards the area for emptying them, and generally when it is inoperative from the collecting point of view per se.
[0038] In the embodiment variant shown in FIGS. 6 , 7 and 8 , it can be seen how the head ( 3 ) transversely and in front of the Archimedean screw ( 4 ) incorporates a shaft ( 19 ) provided with a plurality of radial blades ( 20 ), such that the shaft ( 19 ) and therefore the blades ( 20 ) can be operated by the same drive elements or means of the Archimedean screw ( 4 ), or they can be operated by an independent motor ( 21 ) located in one of the side parts of the head ( 4 ) itself.
[0039] Thus and according to the rotation of the shaft ( 19 ) and therefore of the blades ( 20 ), the floating waste in the water will be introduced in the head ( 3 ) and will reach the Archimedean screw ( 4 ) itself, the collection of the waste therefore being completely efficient, whether the waste is low or high viscosity waste.
[0040] The shaft ( 19 ) of the blades ( 20 ) is located behind the inclined planes ( 5 ) which are arranged in the front of the head ( 3 ), through which access of the oil waste to the head itself is established.
[0041] As previously stated, these blades ( 20 ) may or may not have rectangular windows minimizing their weight, but they always will have suitable dimensions so that the blades ( 20 ) themselves offer sufficient rigidity and strength in driving and introducing the waste towards the head ( 3 ).
[0042] Finally, FIG. 9 shows how rollers ( 22 ) for raising are located between the shaft ( 19 ) with its blades ( 20 ) and the Archimedean screw ( 4 ) itself, the waste raised in the rotation of the blades ( 20 ) being discharged in the rollers for raising such waste towards the Archimedean screw ( 4 ), supplied thereto. | The invention relates to a vessel for collecting petroleum products, in which an Archimedean screw ( 4 ) is used to collect spills, which vessel comprises a T-shaped hull with a central longitudinal narrow body ( 1 ) and a front transverse segment ( 3 ), said hull having no keel and being provided with a planar base, thereby conferring minimum draft thereon, of the order of 50 cm. The containers, which are independent of the hull ( 1 ), are mounted to either side of same and the relative height thereof can be varied in relation to the hull depending on the load level. In addition, each container can be removed in order to be emptied. Consequently the vessel can operate at beaches, ports, rias or any other low-draft areas. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
Generally, the present disclosure relates to the manufacture of sophisticated semiconductor devices, and, more specifically, to various methods of forming V0 structures for semiconductor devices that includes recessing a contact structure and various semiconductor devices having the resulting V0 structural configurations.
2. Description of the Related Art
In modern integrated circuits, such as microprocessors, storage devices and the like, a very large number of circuit elements, especially transistors, are provided and operated on a restricted chip area. Generally, in complex circuitry including complex logic portions, MOS technology is presently a preferred manufacturing technique in view of device performance and/or power consumption and/or cost efficiency. In integrated circuits fabricated using MOS technology, field effect transistors (FETs), such as planar field effect transistors and/or FinFET transistors, are provided that are typically operated in a switched mode, i.e., these transistor devices exhibit a highly conductive state (on-state) and a high impedance state (off-state). The state of the field effect transistor is controlled by a gate electrode, which controls, upon application of an appropriate control voltage, the conductivity of a channel region formed between a drain region and a source region.
To improve the operating speed of FETs, and to increase the density of FETs on an integrated circuit device, device designers have greatly reduced the physical size of FETs over the years, particularly the channel length of transistor devices. As a result of the reduced dimensions of the transistor devices, the operating speed of the circuit components has been increased with every new device generation, and the “packing density,” i.e., the number of transistor devices per unit area, in such products has also increased during that time. Such improvements in the performance of transistor devices has reached the point where one limiting factor relating to the operating speed of the final integrated circuit product is no longer the individual transistor element but the electrical performance of the complex wiring system that is formed above the device level where the actual semiconductor-based circuit elements, such as transistors, are formed in and above the semiconductor substrate.
Typically, due to the large number of circuit elements and the required complex layout of modern integrated circuits, the electrical connections or “wiring arrangement” for the individual circuit elements cannot be established within the same device level on which the circuit elements are manufactured. Accordingly, the various electrical connections that constitute the overall wiring pattern for the integrated circuit product are formed in one or more additional stacked so-called “metallization layers” that are formed above the device level of the product. These metallization layers are typically comprised of layers of insulating material with conductive metal lines or conductive vias formed in the layers of material. Generally, the conductive lines provide the intra-level electrical connections, while the conductive vias provide the inter-level connections or vertical connections between different levels. These conductive lines and conductive vias may be comprised of a variety of different materials, e.g., copper, with appropriate barrier layers, etc. The first metallization layer in an integrated circuit product is typically referred to as the “M1” layer, while the conductive vias that are used to establish electrical connection between the M1 layer and lower level conductive structures (explained more fully below) are typically referred to as “V0” vias. The conductive lines and conductive vias in these metallization layers are typically comprised of copper, and they are formed in layers of insulating material using known damascene or dual-damascene techniques. Additional metallization layers are formed above the M1 layer, e.g., M2/V1, M3/V2, etc. Within the industry, conductive structures below the V0 level are generally considered to be “device-level” contacts or simply “contacts,” as they contact the “device” (e.g., a transistor) that is formed in the silicon substrate.
FIG. 1A is a cross-sectional view of an illustrative integrated circuit product 10 comprised of a plurality of transistor devices 15 formed in and above a semiconductor substrate 12 . A schematically depicted isolation region 13 has also been formed in the substrate 12 . In the depicted example, the transistor devices 15 are comprised of an illustrative gate structure, i.e., a gate insulation layer 16 and a gate electrode 18 , a gate cap layer 20 , a sidewall spacer 22 and simplistically depicted source/drain regions 24 . At the point of fabrication depicted in FIG. 1A , layers of insulating material 17 A, 17 B, i.e., interlayer dielectric materials, have been formed above the product 10 . Other layers of material, such as contact etch stop layers and the like, are not depicted in the attached drawings. Also depicted are illustrative source/drain contact structures 28 which include a combination of a so-called “trench silicide” (TS) region 28 A and a metal region 28 B (such as tungsten). In the depicted process flow, the upper surface of the source/drain contact structures 28 is approximately planar with the upper surface of the gate cap layers 20 . Also depicted in FIG. 1A are a plurality of so-called “CA contact” structures 32 and an illustrative gate contact structure 31 which is sometimes referred to as a “CB contact” structure. The CA contact structures 32 and the CB contact structure 31 are formed to provide electrical connection between the underlying devices and the V0 via level. The CA contact structures 31 are formed to provide electrical contact to the source/drain contact structures 28 , while the CB contact 31 is formed so as to contact a portion of the gate electrode 18 of one of the transistors 15 . In a plan view (not shown), the CB contact 31 is positioned vertically above the isolation region 13 , i.e., the CB contact 31 is not positioned above the active region defined in the substrate 12 . The CA contact structures 32 may be in the form of discrete contact elements, i.e., one or more individual contact plugs having a generally square-like or cylindrical shape, that are formed in an interlayer dielectric material, as shown in FIG. 1A . In other applications (not shown in FIG. 1A ), the CA contact structures 32 may also be a line-type feature that contacts underlying line-type features, e.g., the source/drain contact structures 28 that contact the source/drain region 24 and typically extend across the entire active region on the source/drain region 24 . Typically, the CB contact 31 is in the form of a round or square plug.
In one embodiment, the process flow of forming the source/drain contact structures 28 , CA contacts 32 and CB contact 31 may be as follows. After a first layer of insulating material 17 A is deposited, source/drain contact openings are formed in the first layer of insulating material 17 A that expose portions of underlying source/drain regions 24 . Thereafter, traditional silicide 28 A is formed through the source/drain contact openings, followed by forming a metal 28 B (such as tungsten) on the metal silicide regions 28 A, and performing a chemical mechanical polishing (CMP) process down to the top of the gate cap layer 20 . Then, a second layer of insulating material 17 B is deposited. In older devices, the packing density was such that the openings in the layer of insulating material 17 B for both the CA contact structures 32 and the CB contact structure 31 could be formed using a single patterned etch mask. However, as packing densities have increased with newer device generations, the openings in the layer of insulating material 17 B for the CA contact structures 32 and the CB contact structure 31 are formed separately using two different masking layers—a CA masking layer and a CB masking layer. Thus, in one illustrative process flow, using the CA masking layer, the contact openings for the CA contacts 32 are formed first in the second layer of insulating material 17 B so as to expose portions of the tungsten metallization 28 B of the underlying source/drain contact structure 28 . Then the CA masking layer is removed and the CB masking layer is formed over the second layer of insulating material 17 B and in the previously formed CA contact openings formed therein. Next, using the CB masking layer, the opening for the CB contact 31 is formed in the second layer of insulating material 17 B and through the gate cap layer 20 so as to expose a portion of the gate electrode 18 . Thereafter, the CB masking layer is removed and the CA contacts 32 and the CB contact 31 are formed in their corresponding openings in the second layer of insulating material 17 B by performing one or more common metal deposition and CMP process operations, using the second layer of insulating material 17 B as a polish-stop layer to remove excess material positioned outside of the contact openings. The CA contacts 32 and CB contact 31 typically contain a uniform body of metal, e.g., tungsten, and may also include one or more metallic barrier layers (not shown) positioned between the uniform body of metal and the layer of insulating material 17 B. The source/drain contact structures 28 , the CA contacts 32 and the CB contact 31 are all considered to be device-level contacts within the industry.
Also depicted in FIG. 1A is the first metallization layer—the so-called M1 layer—of the multi-level metallization system for the product 10 formed in a layer of insulating material 34 , e.g., a low-k insulating material. A plurality of conductive vias—so-called V0 vias 40 —are provided to establish electrical connection between the device-level contacts—CA contacts 32 and the CB contact 31 —and the M1 layer. The M1 layer typically includes a plurality of metal lines 38 that are routed as needed across the product 10 .
FIGS. 1B-1F depict a semiconductor device with self-aligned contacts where a line-type CA structure 30 ( FIG. 1C ) was formed using one illustrative prior art technique. In this illustrative example, the CA contact structure 30 is not formed in a separate layer of insulating material, as was the CA contact structures 32 (in the layer 17 B) described above. Rather, in this process flow, the upper metal portion of the source/drain contact structure (positioned below the level of the gate cap layers 20 ) serves as the “CA contact structure.” In this process flow, only the CB contact is formed above the gate cap layers 20 in a separate layer of insulating material. That is, using this process flow, the formation of a separate CA contact in a layer of insulating material positioned above the level of the gate cap layers 20 is omitted, and only a single masking layer—the CB masking layer—is used to form the equivalent of the CA contacts 32 and the gate contact 31 described above. However, relative to the process flow described in connection with FIG. 1A above, this process flow does require the formation of an extended-length V0 via to contact the CA contact structure 30 , as described more fully below.
FIG. 1B depicts an illustrative prior art integrated circuit product 10 comprised of first and second transistors 15 A, 15 B formed in and above a semiconductor substrate 12 . In the depicted example, each of the transistors 15 A, 15 B is comprised of the gate insulation layer 16 and the gate electrode 18 , the gate cap layer 20 and a sidewall spacer 22 . Typically, the gate cap layer 20 and the sidewall spacer 22 are made of a material such as silicon nitride and their purpose is to effectively encapsulate and protect the gate structure. The gate structure may be formed using either gate first or replacement gate techniques. In the case where the gate structure is formed using replacement gate techniques, the cap layer 20 is formed after a sacrificial gate structure (not shown) is removed and after a replacement gate structure (e.g., high-k insulation layer and one or more metal layers is formed in the position previously occupied by the removed sacrificial gate structure). With continuing reference to FIG. 1B , also depicted are illustrative raised source/drain regions 24 and a layer of insulating material 26 (e.g., silicon dioxide) that is formed above the product 10 and planarized.
FIGS. 1B-1F will only depict the formation of a source/drain contact structure between the gate structures 15 A, 15 B so as to facilitate explanation. Those skilled in the art will appreciate that, in practice, a corresponding source/drain contact structure will be formed for all of the source/drain regions, i.e., on the source/drain region to the left of the gate structure 15 A and on the source/drain region to the right of the gate structure 15 B.
Accordingly, FIG. 1C depicts the product 10 after several process operations were performed to form a so-called self-aligned contact that is conductively coupled to the raised source/drain region 24 . First, a patterned etch mask (not shown) was formed above the product 10 so as to expose the area between the gate structures 15 A- 15 B. Thereafter, at least the insulating material 26 was etched selectively relative to the sidewall spacers 22 and the gate cap layer 20 to thereby expose the raised source/drain region 24 . Next, the patterned etch mask was removed and a trench silicide structure 28 A was formed on the exposed source/drain region 24 by performing traditional silicide processing operations. Thereafter, a line-type CA contact structure 30 comprised of, for example, tungsten, was formed so as to be conductively coupled to the trench silicide structure 28 A. In one embodiment, the line-type CA contact structure 30 may be formed of a material such as tungsten and it may extend across substantially the entire active region of the substrate 12 , just like the trench silicide structure 28 A. In one particular example, the line-type CA contact structure 30 may be formed by overfilling the area above the trench silicide structure 28 A with tungsten and thereafter performing a CMP process.
FIG. 1D depicts the product 10 after several process operations were performed. First, a layer of material 32 having a substantially uniform thickness was formed above the product depicted in FIG. 1C . The substantially uniform thickness of the layer of material 32 may vary depending upon the particular application. In one example, the layer of material 32 may be a material such as N-block (SiCNH). Thereafter, a patterned layer of insulating material 34 , such as a low-k material (k value less than 3.3), having an opening 34 A formed therein, was formed above the layer of material 32 . The product depicted in FIG. 1D is the result of initially blanket depositing the layer of insulating material 34 above the product 10 , and thereafter patterning the layer of material 34 through a patterned etch mask (not shown) so as to form the patterned layer of insulating material 34 , with the opening 34 A, as depicted in FIG. 1D .
FIG. 1E depicts the product 10 after several process operations were performed. First, the layer of material 32 was patterned using a patterned etch mask (not shown) so as to define the opening 32 A, as depicted in FIG. 1E . The opening 32 A is for the conductive V0 via 40 that will be subsequently formed therein. Ideally, the opening 32 A will be relatively large in the lateral width direction so that the resulting V0 via 40 will also be relatively large—a “fat” V0. A relatively larger V0 is desirable in that it reduces the electrical resistance of the V0 structure 40 and it makes it easier to actually contact the underlying CA contact 30 , i.e., the chances of missing the CA contact 30 decrease if the V0 via is relatively wide. Then, the conductive lines 38 and conductive V0 vias 40 were formed in the openings 34 A, 32 A, respectively, by depositing one or more conductive materials, e.g., barrier layers and copper, and performing a polarization process to remove excess conductive materials positioned outside of the opening 34 A. FIG. 1E depicts an idealized V0 structure 40 that results when the etch process that is performed to form the opening 32 A in the material layer 32 is timed perfectly such that there is effectively no consumption of the underlying gate cap layers 20 exposed by the opening 32 A. Note that, in this process flow, the V0 via must extend down to at least the level of the upper surface of the gate cap layer 20 so that electrical contact may be made to the CA contact 30 .
FIG. 1F depicts a situation wherein the idealized V0 structure 40 depicted in FIG. 1D is not achieved. As noted above, the opening 32 A in the material layer 32 is formed such that it is relatively wide so that the ultimate V0 via will also be relatively wide or “fat.” As shown in FIG. 1F , the width of the opening 32 A is such that it typically overlaps the gate cap layer 20 of one or both of the transistors, as indicated by the dimensioned arrows 35 . Unfortunately, there is typically little etch selectivity between the material of the material layer 32 , which is frequently N-block, and the material of the gate cap layers 20 , which is typically silicon nitride. As a result, if the etch process that is performed to form the opening 32 A in the material layer 32 is not timed perfectly, some or all of the underlying gate cap 20 may also be consumed, thereby exposing a portion of the gate electrode 18 . As a result, when the V0 via 40 is formed, the V0 via 40 may actually contact the exposed gate structures 18 , as indicated in the dashed lines 37 . Such a situation results in an electrical short between at least the V0 structure 40 (and perhaps the CA contact 30 ) and the gate electrode 18 . Such a situation can result in complete device failure.
The present disclosure is directed to various methods of forming V0 structures for semiconductor devices, and various semiconductor devices having the resulting V0 structural configurations, that may solve or reduce one or more of the problems identified above.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.
Generally, the present disclosure is directed to various methods of forming V0 structures for semiconductor devices that includes recessing a contact structure and various semiconductor devices having the resulting V0 structural configurations. One illustrative method disclosed herein includes, among other things, forming a source/drain contact structure between two spaced-apart transistor gate structures, recessing the source/drain contact structure to define a recessed source/drain contact having a recessed upper surface, wherein the recessing of the source/drain contact structure defines a source/drain contact etch cavity, and performing a conformal deposition process to deposit a conformal second layer of insulating material above a first layer of insulating material, in the source/drain contact etch cavity and on the recessed upper surface of the recessed source/drain contact. In this example the method also includes forming a third layer of insulating material above the conformal second layer of insulating material, forming an opening in the conformal second layer of insulating material so as to expose at least a portion of the recessed upper surface of the recessed source/drain contact, and forming a V0 via such that it is conductively coupled to the exposed portion of the recessed source/drain contact structure, the V0 via being at least partially positioned in the opening in the conformal second layer of insulating material.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure 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:
FIGS. 1A-1F depict a semiconductor device with self-aligned contacts where a line-type CA structure was formed using one illustrative prior art technique;
FIGS. 2A-2F depict various illustrative methods disclosed herein for forming V0 structures for semiconductor devices and devices that include the resulting V0 structural configurations; and
FIGS. 3A-3J depict other illustrative methods disclosed herein for forming V0 structures for semiconductor devices that includes recessing a contact structure and devices that include the resulting V0 structural configurations.
While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION
Various illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
The present disclosure is directed to various methods of forming V0 structures for semiconductor devices that includes recessing a contact structure, and various semiconductor devices having the resulting V0 structural configurations. As will be readily apparent to those skilled in the art upon a complete reading of the present application, the methods disclosed herein may be employed with a variety of different technologies, e.g., NMOS, PMOS, CMOS, etc., and in manufacturing a variety of different integrated circuit products, including, but not limited to, logic products, memory products, etc. As will be appreciated by those skilled in the art after a complete reading of the present application, the methods disclosed herein may also be employed when manufacturing a variety of different type devices, e.g., planar devices, FinFET devices, nanowire devices, etc. Lastly, the gate structures for the illustrative transistor devices depicted herein may be formed using either “gate-first” or “replacement gate” manufacturing techniques. With reference to the attached figures, various illustrative embodiments of the methods and devices disclosed herein will now be described in more detail.
FIGS. 2A-2F depict various illustrative methods disclosed herein for forming V0 structures. FIG. 2A is a simplified view of an illustrative semiconductor product 100 at an early stage of manufacturing that corresponds to that depicted in FIG. 1C above, i.e., after a line-type CA contact 30 was formed. That is, the CA contact 30 depicted in these drawings was formed without the use of a traditional CA masking layer. FIGS. 2A-2F will depict the formation of a source/drain contact structure (i.e., the TS structure 28 A and the CA contact 30 ) above each of the source/drain regions 24 . As depicted, the upper surfaces of the CA contact 30 are substantially planar with the upper surface of the gate cap layers 20 .
FIG. 2B depicts the product 100 after a layer of material 102 having a non-uniform thickness was formed on the product. More specifically, the non-uniform thickness layer of material 102 is formed such that its thickness 102 B above the silicon nitride gate cap layers 20 is substantially thicker than its thickness 102 A above the tungsten CA contact structures 30 . In one illustrative embodiment, the non-uniform thickness layer of material 102 may be formed such that the thickness 102 B is at least 10-30 nm greater than the thickness 102 A. In absolute terms, the thickness 102 A may fall within the range of about 5-25 nm, while the thickness 102 B may fall within the range of about 15-55 nm. In one illustrative example, the non-uniform thickness layer of material 102 may be a layer of silicon nitride that is formed by the TELOS process (by LAM Research™) wherein the silicon nitride material selectively forms on the silicon nitride gate cap layer 20 at a much faster rate than it does on the tungsten CA contacts 30 . In general, this process operation involves coating the upper metal surface of the tungsten CA contacts 30 with a self-assembled monolayer (SAM—not shown) so as to retard the growth of the layer of material 102 above the CA contacts 30 . Generally, this SAM makes the metal surface hydrophobic. Accordingly, the layer of material 102 will grow at a faster rate above the silicon nitride gate cap layers 20 than it does above the upper metal surfaces of the metal CA contacts 30 .
FIG. 2C depicts the product 100 a layer of insulating material 104 , such as a low-k material (k value less than 3.3), was blanket deposited above the product 100 .
FIG. 2D depicts the product 100 after the layer of insulating material 104 was patterned using a patterned etch mask (not shown) so as to define an opening 104 A in the layer of insulating material 104 . The opening 104 A exposes a portion of the non-uniform thickness layer of material 102 for further processing.
FIG. 2E depicts the product 100 after several process operations were performed. First, a patterned etch mask 105 (such as a patterned layer of photoresist) having an opening 105 A was formed above the product 100 . The opening 105 A corresponds to an opening for a V0 via that will be formed in the non-uniform thickness layer of material 102 to establish electrical contact to the underlying CA contact 30 . So as to facilitate explanation, only the formation of a V0 via for the middle CA contact 30 will be depicted in the following drawings. Of course, as will be appreciated by those skilled in the art, a similar V0 via will be formed for each of the CA contacts 30 . Thereafter, an etching process was performed through the patterned etch mask 105 so as to define an opening 102 X in the non-uniform thickness layer of material 102 . The opening 102 X exposes at least a portion of the underlying CA contact 30 . Some recessing of the exposed portion of the CA contact 30 may occur during this etching process, but such recessing is not depicted in the attached drawings.
In the depicted example, the lateral width 105 X of the opening 105 A is such that it overlaps the gate electrode 18 of one of the transistors. More specifically, the opening 105 A exposes both the thinner ( 102 A) and thicker ( 102 B) portions of the non-uniform thickness layer of material 102 . Due to the presence of the thicker portions 102 B of the non-uniform thickness layer of material 102 above the gate electrode, there is more material present to protect the gate electrode, e.g., the combined thickness of the gate cap layer 20 plus the thicker portion 102 B of the non-uniform thickness layer of material 102 . Additionally, the thicker material that is present above the gate electrode provides a greater process window when performing the etching process as the etching process does not have to be timed as accurately as when a uniform thickness layer of material (such as the layer 32 shown in FIG. 1D ) was formed above the gate cap layers 20 . Moreover, due to the presence of the thicker portions 102 B of the non-uniform thickness layer of material 102 , the lateral width 105 X of the opening 105 A, and the corresponding via opening 102 X, may be made larger, thereby resulting in a larger V0 structure, which is desirable.
Next, as shown in FIG. 2F , after the patterned etch mask 105 was removed, known process operations were performed to form a conductive V0 via 106 and a conductive metal line 108 in the M1 metallization layer. These conductive structures may be comprised of a variety of different materials, e.g., copper, and may also include one or more barrier layers (not shown). In general, conductive materials may be formed in the openings 102 X and 104 A, and one or more CMP processes may be performed to planarize the upper surface of the layer 104 and to remove excess conductive material positioned outside of the opening 104 A. At the point of fabrication depicted in FIG. 2F , additional metallization layers (not shown) may be formed above the M1 layer, e.g., M2/V1, M3/V2, etc.
FIGS. 3A-3J depict other illustrative methods disclosed herein for forming V0 structures for semiconductor devices and devices that include the resulting V0 structural configurations. In this illustrative process flow, the CA contact 30 will be formed using a CA masking layer (not shown). FIGS. 3A-3J will depict the formation of a source/drain contact structure above only the middle source/drain region 24 so as to facilitate explanation of the present subject matter. Of course, those skilled in the art will appreciate that, in practice, a corresponding source/drain contact structure will be formed for all of the source/drain regions, i.e., on the source/drain region to the left of the gate structure 15 A and on the source/drain region to the right of the gate structure 15 B. FIG. 3A is a simplified view of an illustrative semiconductor product 100 at an early stage of manufacturing after the source/drain regions 24 and the gate structures were formed and after a planarization process was performed on a layer of insulating material 26 , e.g., silicon dioxide. Thereafter, another layer of insulating material 27 , e.g., silicon nitride or silicon dioxide, was formed above the gate cap layers 20 and the layer of insulating material 26 . In this example, the gate structures may replacement gate structures wherein the cap layers 20 were formed after the materials for the replacement gate structure were formed in the space (gate cavity) between the sidewall spacers 22 and recessed.
FIG. 3B depicts the product 100 after several process operations were performed to form a so-called self-aligned contact that is conductively coupled to the middle raised source/drain region 24 . First, a patterned etch mask (a CA etch mask—not shown) was formed above the product 10 so as to expose the area between the gate structures 15 A- 15 B. Thereafter, one or more etching processes were performed through the patterned CA etch mask to selectively remove portions of at least the layers of insulating material 26 , 27 relative to the sidewall spacers 22 and the gate cap layer 20 . This process operation exposes the raised source/drain region 24 . Next, the patterned CA etch mask was removed and the above-described trench silicide (TS) structure 28 A was formed on the exposed source/drain region 24 by performing traditional silicide processing operations. Thereafter, a line-type CA contact structure 30 comprised of, for example, tungsten, was formed so as to be conductively coupled to the trench silicide structure 28 A. In one particular example, the line-type CA contact structure 30 may be formed by overfilling the area above the trench silicide structure 28 A with tungsten and thereafter performing a CMP process to planarize the upper surface of the layer 27 and thereby remove any excess conductive materials.
FIG. 3C depicts the product 100 after a recess etching process is performed to remove at least some of the layer 27 , and, in the depicted example, substantially all of the layer 27 relative to the surrounding materials. This recess etching process exposes an upper portion of the CA contact structure 30 .
Then, as shown in FIG. 3D , a layer of insulating material 120 was formed on the product 100 and a CMP process was performed. The layer of insulating material 120 may be comprised of a variety of different materials, e.g., silicon nitride, etc., and it may be formed using traditional techniques, e.g., chemical vapor deposition (CVD), etc. At this point, the layer of insulating material 120 may have a thickness that falls within the range of about 15-30 nm. At the point depicted in FIG. 3D , the upper surface of the layer of insulating material 120 is at or near the same level as the upper surface of the CA contact structure 30 .
Next, as shown in FIG. 3E , a contact recess etching process is performed to reduce the height or thickness of the CA contact structure 30 . This recessing operation results in the formation of a CA contact etch cavity 121 above the recessed CA contact structure 30 . This recess etching process also results in the formation of an opening 122 in the layer of insulating material 120 . At this point in fabrication, the opening 122 has a lateral width 122 A.
FIG. 3F depicts the product after a timed isotropic etching process was performed on the layer of insulating material 120 . This etching process has the effect of increasing the lateral width of the opening 122 to a larger dimension 122 B and also results in a thinning of the layer of insulating material 120 , which has now been re-labeled with the number 120 A to reflect its reduced thickness. In one illustrative embodiment, the reduced thickness layer of material 120 A may have a thickness of about 6-15 nm. This process operation also has the effect of increasing the lateral width of the CA contact etch cavity 121 , which has now been re-labeled with the number 121 A to reflect its increased lateral width.
FIG. 3G depicts the product 100 after several process operations were performed. First, a conformably deposited layer of insulating material 124 is formed on the product 100 . In one illustrative embodiment, the layer of insulating material 124 may have a thickness of about 5-20 nm, and it may be formed by performing a conformal CVD process. The layer of insulating material 124 may only partially fill the CA contact etch cavity 121 A. The layer of insulating material 124 may be comprised of a variety of different insulating materials, e.g., silicon nitride, N-Block, silicon oxynitride, silicon carbon boron nitride, etc. Next, the above-described layer of insulating material 104 was blanket deposited above the product 100 .
FIG. 3H depicts the product 100 after the layer of insulating material 104 was patterned using a patterned etch mask (not shown) so as to define the opening 104 A in the layer of insulating material 104 . The opening 104 A exposes a portion of the layer of insulating material 124 for further processing.
FIG. 3I depicts the product 100 after several process operations were performed. First, a patterned etch mask 107 (such as a patterned layer of photoresist) having an opening 107 A was formed above the product 100 . The opening 107 A corresponds to an opening for a V0 via that will be formed in the layer of insulating material 124 to establish electrical contact to the underlying CA contact 30 . So as to facilitate explanation, only the formation of a V0 via for the middle CA contact 30 will be depicted in the following drawings. Of course, as will be appreciated by those skilled in the art, a similar V0 via will be formed for each of the CA contacts 30 . Thereafter, an etching process was performed through the patterned etch mask 107 so as to define an opening 124 X in the layer of insulating material 124 . The opening 124 X exposes at least a portion of the underlying CA contact 30 (that was exposed prior to the formation of the layer of insulating material 124 (see FIG. 3E )).
In the depicted example, the lateral width 107 X of the opening 107 A is such that it overlaps the gate electrode 18 of one of the transistors on the left. However, due to the presence of the reduced thickness layer of material 120 A being positioned vertically above the gate electrode, there is more material present to protect the gate electrode, e.g., the combined thickness of the gate cap layer 20 plus the thickness of the reduced thickness layer of material 120 A. Additionally, by recessing the CA contact structure 30 (and thereby forming the CA contact etch cavity 121 (or 121 A) and the opening 122 in the layer of insulating material 120 / 120 A) prior to forming the layer of insulating material 124 , there is less protective material above the CA contact structure 30 than there is above the gate electrode. This provides a greater process window when performing the etching process on the layer of insulating material 124 as the etching process does not have to be timed as accurately as when a uniform thickness layer of material (such as the layer 32 shown in FIG. 1D ) was formed above the gate cap layers 20 and the CA contact structure 30 . Moreover, due to the presence of the thicker portions of material above the gate electrodes, the lateral width 107 X of the opening 107 A, and the corresponding via opening 124 X, may be made larger, thereby resulting in a larger V0 structure.
Next, as shown in FIG. 3J , after the patterned etch mask 107 was removed, known process operations were performed to form the above-described conductive V0 via 106 and a conductive metal line 108 in the M1 metallization layer. At the point of fabrication depicted in FIG. 3J , additional metallization layers (not shown) may be formed above the M1 layer, e.g., M2/V1, M3/V2, etc.
The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the process steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below. | One illustrative method disclosed herein includes, among other things, forming a source/drain contact structure between two spaced-apart transistor gate structures, recessing the source/drain contact structure to define a source/drain contact etch cavity and depositing a conformal second layer of insulating material above a first layer of insulating material and in the source/drain contact etch cavity. The method also includes forming a third layer of insulating material above the conformal second layer of insulating material, forming an opening in the conformal second layer of insulating material and forming a V0 via that is conductively coupled to the exposed portion of the recessed source/drain contact structure. | 7 |
This is a division of application Ser. No. 09/669,969 on Sep. 26, 2000, now U.S. Pat. No. 7,081,312.
TECHNICAL FIELD
This invention relates to fuel cell systems and components, and more particularly to a fuel cell system that combines exothermic and endothermic processes in one reaction vessel.
BACKGROUND OF THE INVENTION
Alexander Grove invented the first fuel cell in 1839. Since then most of the fuel cell development has been primarily limited to applications supported by the government, such as the United States National Aeronautics and Space Administration (NASA), or to utility plants applications. However, recent developments in materials of construction and processing techniques have brought fuel cell development closer to significant commercial applications. A primary advantage of fuel cells is that fuel cells can convert stored energy to electricity with about 60-70 percent efficiency, with higher efficiencies theoretically possible. Further, fuel cells produce virtually no pollution. These advantages make fuel cells particularly suitable for vehicle propulsion applications and to replace the internal combustion engine which operates at less than 30 percent efficiency and can produce undesirable emissions.
Although fuel cells are desirable for vehicle propulsion applications, the fuel cell must be incorporated into a complicated on-board system that includes a fuel cell stack and auxiliary equipment. The following brief discussion of the operation and purpose of the fuel cell stack and its auxiliary equipment will be helpful in understanding the advantages and desirability of the present invention.
Fuel Cell Operation
A fuel cell principally operates by oxidizing an element, compound or molecule (that is, chemically combining with oxygen) to release electrical and thermal energy. Thus, fuel cells operate by the simple chemical reaction between two materials such as a fuel and an oxidant. Today, there are a variety of fuel cell operating designs that use many different fuel and oxidant combinations. However, the most common fuel/oxidant combination is hydrogen and oxygen.
In a typical fuel cell, hydrogen is consumed by reacting the hydrogen with oxygen from air to produce water, electrical energy and heat. This is accomplished by feeding the hydrogen over a first electrode (anode), and feeding the oxygen over a second electrode (cathode). The two electrodes are separated by an electrolyte which is a material that allows charged molecules or “ions” to move through the electrolyte. There are several different types of electrolytes that can be utilized including the acid-type, alkaline-type, molten-carbonate-type and solid-oxide-type. The so-called PEM (proton exchange membrane) electrolytes (also known as a solid polymer electrolyte) are of the acid-type, and potentially have high-power and low-voltage, and thus are desirable for vehicle applications.
FIG. 1 shows a fuel cell that has been simplified for purposes of illustrating the operation of a fuel cell. In the proton exchange membrane based fuel cell 10 shown, a hydrogen gas stream 12 is fed into a first sealed chamber or manifold (in the case of a fuel cell stack) 14 and over a first electrode (anode) 24 and on to a first face 16 (the anode side) of a proton exchange membrane assembly 18 . The proton exchange membrane assembly 18 typically includes the electrolyte membrane 19 having two faces, and on each face there is a catalyst, usually a noble metal such as platinum, and an electrically conductive diffusion media (such as a carbon fiber mat) overlying the catalyst. The catalyst and diffusion media are not shown in FIG. 1 . The catalyst on the anode face of the assembly promotes the dissociation of hydrogen molecules and the catalyst on the cathode face of the assembly promotes the dissociation of oxygen molecules and a reaction of oxygen with hydrogen protons to produce water. The electrolyte membrane 19 allows the diffusion of hydrogen ions 26 from one electrode 24 to another electrode 34 . FIG. 1 is a simple illustration attempting to depict the diffusion of these hydrogen ions 26 from the anode to the cathode side of the electrolyte membrane. However, the electrolyte membrane 19 does not include channels as shown in FIG. 1 .
A compressed air stream 22 is supplied to a second chamber or manifold (for a fuel cell stack) 15 in a manner so that the compressed air flows over a second electrode (cathode) 34 and on to a second face 20 of the proton exchange membrane assembly 18 . The proton exchange membrane assembly 18 is selective and allows only the hydrogen protons 26 to pass through the membrane assembly 18 rejecting larger diatomic hydrogen molecules 28 . When a single hydrogen proton (or its equivalent) 26 passes through the membrane, it leaves behind an electron 30 . The electrons 30 that are left behind can be collected in the electrode (conductor) 24 . Typically fuel cell systems include a stack of single cells (fuel cell stack) with adjacent cells sharing a common electrode. In that case, the electrodes 24 , 34 would be bipolar. Preferably each electrode 24 , 34 includes channels 25 formed therein through which either hydrogen or oxygen flows.
The concentrated electrons in the electrode 24 causes a potential negative voltage on the electrode 24 due to the excess of electrons (because the electrons are negatively charged). When the oxygen molecules are directed to the second face 20 of the proton exchange membrane assembly 18 , the oxygen meets the hydrogen proton 26 as the proton passes through the membrane. The chemical reaction of the hydrogen proton 26 and the oxygen on the cathode side of the cell requires electrons and therefore a shortage of electrons is created. The needed electrons can be supplied by a second electrode 34 (that is, the cathode electrode). The oxygen and the hydrogen proton 26 , in the presence of the electrons 30 from the second electrode 34 , easily combined to produce water 32 . The reactions at the electrodes are as follows:
Anode 2H 2 →4H + +4e − Cathode O 2 +4e − +4H + →2H 2 O.
With two electrodes 24 , 34 in the fuel cell system (the anode and the cathode) an electrical potential exist between the two electrodes. That is, the hydrogen electrode 24 has an excess of electrons and the oxygen electrode 34 needs electrons. The electrical potential can be utilized by placing an electrical load, such as electrical motor 36 (to propel a vehicle) between the anode 24 and the cathode 34 . Since electrical energy is used as it goes around the loop, the only by-products of this fuel system are water vapor and the heat loss through inefficiency of the cell itself (or about 30 percent of the power). With 70 percent efficiency, this process is significantly more attractive for extracting stored energy than an internal combustion engine that typically extracts only 20-30 percent of stored fuel energy.
Both hydrogen and oxygen are each supplied to the fuel cell in excess to provide the greatest rate of reaction possible. The hydrogen gas stream will be under pressure of about 3 bars if it is produced from a fuel reformation reaction and therefore the oxygen stream 22 must be pumped up to the same pressure to avoid damage to the proton exchange membrane and the catalyst of the assembly 18 . Any water produced or remaining on either side of the fuel cell is removed and is discharged or may be sent through a water/vapor stream line 38 to a water reservoir (such as the holding tank 46 shown in FIG. 2 ) for use in other components or for use in the fuel cell at startup. The effluent or tail gas exhaust stream 40 , 42 from both sides of the fuel cell are discharged to the atmosphere or preferably are supplied to a combustor for burning and producing heat needed for other operations such as the fuel reformation process described hereafter. Since the reactants are supplied to the fuel cell in excess, tail gas exhaust stream 40 from the anode side contains hydrogen and the tail gas exhaust stream 42 from the cathode side contains oxygen. Both of the fuel cell tail gas streams 40 , 42 may be combusted in a catalytic combustor to provide heat for other components in the fuel cell system.
Preferably the fuel cell is maintained at a temperature of about 80 degrees Celsius or greater. Maintaining this temperature may require heat to be added or removed from the fuel cell stack. Often heat must be supplied to the fuel cell at startup. This heat can be supplied by a catalytic or flame combustor. However, during post startup or normal operation of the fuel cell, heat is generated by the fuel cell and the generated heat can be removed by any of a variety of heat exchange methods but preferably is removed using a liquid coolant.
Auxiliary Equipment
As will be appreciated from the forgoing, fuel cell systems require a variety of auxiliary equipment such as pumps, heat exchangers, fuel processors, combustors, water separation and collection equipment, hydrogen cleanup or purification systems and so on to support the operation of the fuel cell itself. Auxiliary equipment that is of interest with respect to this invention is discussed below.
Although compressed or liquefied hydrogen could be used to operate a fuel cell in a vehicle, to date this is not practical. The use of compressed or liquefied hydrogen ignores the extensive infrastructure currently being used to supplying gasoline for internal combustion engine automobiles and trucks. Consequently, it is more desirable to utilize a fuel such as methanol, gasoline, diesel, methane and the like to provide a hydrogen source for the fuel cell. However, the methanol, gasoline, diesel, methane and the like must be reformed to provide a hydrogen gas source. This is accomplished by using methanol or gasoline fuel processing or reforming equipment, and hydrogen cleanup or purification equipment.
Fuel cell systems often include a fuel processing section which reforms the fuel such as methanol, gasoline, diesel, methane and the like to produce hydrogen and a variety of other byproducts. However, these reforming (reformation) processes are endothermic and require energy input to drive the reformation reaction.
Typically, a catalytic or flame combustor is utilized to provide heat for the reforming process. Most often, this is accomplished by utilizing a working fluid (liquid or gas) loop that transfers heat from the combustion process to the reforming process. However, the response time for heat transfer needed during startup and transient conditions of the fuel cell are less than optimal when the system uses a fluid to transfer heat between the combustor and the reformer vessel. Further, the working fluid loop, associated heat exchangers and piping add to the overall mass and volume of the fuel cell system.
Thus it would be desirable to provide a low-cost, low-weight system for supplying heat to a fuel cell reforming process and wherein the system is responsive to the heat load fluctuations of the reforming process. The present invention overcomes some of the inefficiencies of the prior art
SUMMARY OF INVENTION
The invention includes a reaction vessel that integrates and balances an endothermic process with at least one exothermic process of a fuel cell system. Preferably the exothermic process is conducted in stages to provide more uniform and/or controllable heat generation and exchange, and to produce a uniform, and/or controllable temperature profile in the endothermic reaction process, if desired (depending on the fuel used). The invention eliminates the working fluid heat exchange loop of prior art fuel reforming sections that had unsatisfactory response times at startup, and during transient conditions, and also added to the overall mass and volume of the fuel cell system.
One embodiment of the invention includes a reaction vessel having an outer shell and catalyst carried in the shell for promoting an endothermic reaction. The reaction vessel is constructed and arranged to charge an endothermic reactant(s) into the shell. A plurality of heat exchanger devices are also provided having portions separately positioned and carried within the shell. Each heat exchanger device is independently controlled from the other heat exchanger devices so that heat transferred by the heat exchanger devices to the catalyst, and the temperature of the catalyst in the shell, may be varied at different locations within the reaction vessel. Preferably the reaction vessel is constructed and arranged so that exothermic reactants may be charged into each heat exchanger device and combusted to generate heat for driving the endothermic reaction occurring in another portion of the reaction vessel. The exothermic reactants may include anode and cathode exhaust streams from a fuel cell stack.
Another embodiment of the present invention includes a reaction vessel having a plurality of endothermic reaction sections and a plurality of heat transfer devices. Each heat transfer device is associated with an endothermic reaction section so that sufficient heat may be transferred to the endothermic reaction section and so as to control the temperature profile of the endothermic reaction section within a predetermined range. The endothermic reaction-sections may be spaced apart from each other and so that a heat transfer device is positioned between adjacent spaced apart endothermic reaction sections.
Another embodiment of the present invention includes a combination reaction vessel having multiple staged catalytic combustion chambers and a plurality of endothermic reaction chambers. Each endothermic reaction chamber has a combustion chamber adjacent thereto so that heat generated in the combustion chamber is transferred to the adjacent endothermic reaction chamber. Each catalytic combustion chamber may have a plurality of reactant charge openings for supplying at least one reactant to the catalytic combustion chamber. The charge openings may be positioned within the catalytic combustion chamber to provide a substantially uniform temperature along the length of the catalytic combustion chamber.
Another embodiment of the invention includes a charge manifold having a plurality of charge pipes extending therefrom. Each charge pipe extends into an exothermic reaction chamber. The charge pipes have charge holes provided along the length of each charge pipe so the fuel or oxidant may be charged into the combustion reaction chamber through the charge holes. Preferably valves are associated with each charge pipe and a controller is provided for selectively controlling the amount of fuel or oxidant charged to each exothermic reaction chamber. Each charge pipe may separate adjacent side-by-side exothermic reaction chambers. A directional flow header may be provided at the end of each exothermic reaction chamber for directing gases exiting one exothermic reaction chamber to the entrance of an adjacent side-by-side exothermic reaction chamber.
Another embodiment of present invention includes the incorporation of a fuel/water vaporizer into the combination reaction vessel. A fuel/water mixture is injected into a plurality of vaporization chambers and is vaporized by heat generated by the catalytic combustion of a fuel mixture charged into a plurality of exothermic reaction chambers. No catalyst is provided in the vaporization chambers. An oxidant and fuel are charged into the exothermic reaction chambers and catalytically combusted to produce heat to vaporize the fuel/water mixture.
Another embodiment of present invention includes a combination reaction vessel that incorporates an exothermic and endothermic reaction. The reaction vessel includes a plurality of endothermic reaction chamber sections that are spaced apart vertically and horizontally. A plurality of exothermic reaction chamber sections are also provided in a spaced apart fashion so that a partition section is provided between laterally spaced apart exothermic reaction chamber sections. The partition sections provide for staged adiabatic reforming of the fuel/water mixture. The catalyst loading in different portions of the endothermic reaction chamber sections may be varied as desired.
These and other objects, features and advantages of present invention will become apparent from the following brief description of drawings, detailed description of preferred embodiments, and appended claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a fuel cell useful in the present invention;
FIG. 2 is a schematic illustration of a fuel cell system useful in a present invention;
FIG. 3 is a sectional view of a combination reaction vessel for housing an endothermic and an exothermic reaction according to the present invention;
FIG. 4 is a sectional view of an alternative embodiment of a combination reaction vessel for housing an endothermic and an exothermic reaction according to the present invention;
FIG. 5 is a sectional view of an alternative embodiment of a combination reaction vessel for housing an endothermic and an exothermic reaction according to the present invention;
FIG. 6 is an exploded, prospective view, with portions broken away, of an alternative embodiment of a combination reaction vessel for housing an endothermic and an exothermic reaction according to the present invention; and
FIG. 7 is a sectional view of an alternative embodiment of a reaction vessel for housing a staged endothermic reaction according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 2 , the fuel cell system according to the present invention includes a fuel cell (or fuel cell stack) 10 . The system may also include the following auxiliary equipment to support the fuel cell stack 10 . Water is provided and held in a water reservoir or holding tank 46 which is connected to a vaporizer 48 by water line 44 . A fuel source is provided and held in a tank 52 that is also connected to the vaporizer 48 by line 50 . Preferably the fuel used is methanol, gasoline, diesel, methane and the like. The fuel and water may be vaporized by any method known to those skilled in the art, but preferably the heat for the vaporization step is supplied by a heat exchanger 39 in the vaporizer that catalytically combusts hydrogen 40 ′ and oxygen 42 ′ from the fuel cell stack 10 exhaust. Alternatively, the vaporizer may be included as an integral part of the reaction vessel 54 as will be described hereafter. The fuel and water are vaporized together (or may be vaporized separately) and a resultant vaporized fuel/water stream is delivered via line 58 to an endothermic reaction section of a combination reaction vessel 54 . Preferably a fuel reformation process is conducted in the endothermic reaction section.
The combination reaction vessel 54 also houses an exothermic reaction section. The exothermic reaction may be, for example, catalytic combustion of a fuel or preferential oxidation of the exhaust stream from the fuel reforming section. If the exothermic reaction process is catalytic combustion, preferably the anode exhaust stream 40 and cathode exhaust stream 42 from the fuel cell 10 are used as the catalytic combustion reactants. The exhaust from the exothermic reaction may be discharged to the atmosphere via line 43 .
The reformation process effluent stream 56 may include hydrogen molecules (H 2 ), CO, CO 2 , N 2 , CH 4 . The reformation process effluent stream 56 may be delivered to a hydrogen purification section 59 to reduce the concentration of CO and hydrocarbons (or carbon based molecules). The hydrogen purification section 59 may include any of a variety of components for purifying the reformation process effluent stream 56 and may include high and low temperature reactors to shift the equilibrium of the stream 56 constituents (thus reducing the concentration of CO), preferential oxidation reactor(s), additional hydrocarbon reforming components, separators, adsorbers and similar equipment. Eventually a hydrogen rich stream 60 is delivered to the anode side of the fuel cell 10 .
As indicated earlier, air 22 is pumped to the cathode side of the fuel cell 10 . The anode and cathode exhaust streams from the fuel cell stack carry water that can be condensed out using a separator/condenser as the stream exits fuel cell stack and the liquid water may be sent to reservoir 46 . Alternatively, the water may be condensed out after the stack effluent passes through exhaust tail gas combustors.
FIG. 3 illustrates a combination reaction vessel 54 for housing an endothermic and an exothermic reaction. The combination reaction vessel 54 includes an endothermic reaction chamber section 62 and an exothermic reaction chamber section 64 that share a common wall or substrate 66 . Each endothermic reaction chamber section 62 and exothermic reaction chamber section 64 includes an associated outside wall 68 , 70 respectively. A catalyst 61 for promoting the reformation reaction of the fuel and water, is provided in the endothermic reaction chamber section 62 . As illustrated in FIG. 3 the catalyst 61 may overlie at least one of the outside wall 68 and/or the substrate 66 . The catalyst 61 may be provided directly on the outside wall 68 or the substrate 66 , or intermediate layers (not shown) may be provided therebetween. The vaporized fuel and water mixture may enter the endothermic reaction chamber section 62 from one end 72 or may be selectively charged to the endothermic reaction chamber through charge lines 74 or openings 75 selectively positioned along the length of the endothermic reaction chamber section 62 . The term “endothermic reactants” as used herein means reactants of an endothermic reaction. In this case, for example, the endothermic reactants are the organic fuel and water.
The exothermic reaction chamber section 64 may be similarly constructed. As illustrated in FIG. 3 , an exothermic catalyst 65 may overlie at least one of the outside wall 70 or substrate 66 . Similarly, the catalyst 65 may be provided directly on the outside wall 70 or the substrate 66 , or intermediate layers (not shown) may be provided therebetween. In one embodiment of the invention, a fuel combustion process may be conducted in the exothermic reaction chamber 64 . An oxidant such as oxygen (from air) may be charged into the chamber section 64 through one end 76 of the chamber and a fuel such as hydrogen or a hydrocarbon may be supplied to the chamber through one or more charge lines 74 ′ or through a charge openings 75 ′ that may be positioned along the length of the exothermic reaction chamber section 64 . Alternatively, the fuel may be charged through the open end 76 and the oxidant supplied through the charge lines 74 ′ or charge openings 75 ′. In another embodiment, an exothermic reaction such as a preferential oxidation reaction to reduce CO or hydrocarbons may be conducted in the exothermic reaction chamber section 64 . In any event, the heat generated by the exothermic reaction in the exothermic reaction chamber section 64 is transferred through the substrate 66 to warm the endothermic reaction chamber section 62 , catalyst 61 and reactants, and to drive (that is, to provide the heat necessary to complete the reaction) the endothermic reaction process. The term “exothermic reactants” as used herein means the reactants of an exothermic reaction. The exothermic reactants may include a fuel such as an organic fuel including, for example, hydrogen, methanol, gasoline, diesel, methane and the like; and an oxidant, such as oxygen in the form of air.
FIG. 4 illustrates an alternative embodiment of the present invention wherein either the endothermic or the exothermic catalyst may be provided on a solid porous substrate 78 or porous pellets 80 or any of a variety materials that would provide increased surface area for either of the catalysts. When the catalyst is on a high surface area material such as a porous block or porous pellets that are carried in the chamber, the catalyst is also considered to be overlying the substrate for purposes of this invention.
FIG. 5 illustrates an alternative embodiment of the present invention wherein a reactant charge pipe 82 extends into one of the reaction chambers 62 , 64 and has a plurality of discharge holes 84 formed therein along the length of the reaction chamber to selectively discharge a reactant into the chamber at predetermined locations. Preferably, the charge pipe 82 delivers a fuel such as hydrogen to the combustion reaction chamber 64 which has an oxidant such as oxygen or air flowing therein. Alternatively, the charge pipe 82 may be used to introduce oxygen to allow for staged preferential oxidation. The use of the reactant charge pipe 82 with discharge holes 84 allows the fuel or oxidant to be supplied in relatively low concentrations so as to reduce the risk of autoignition and also to provide a more uniform heat generation profile along the length of the exothermic reaction chamber 64 . Of course, porous catalyst pellets or another suitable supported catalyst may be provided in the exothermic reaction chamber 64 .
The substrate 66 (shown in FIGS. 3-5 ) may be made from a variety of materials having suitable heat transfer characteristics and may include any of several metals such as stainless-steel, copper, aluminum, or any of a variety of composites, ceramics, compounds or polymer base materials.
As described earlier, when the exothermic reaction produces heat, the heat is transferred through the substrate wall 66 separating an adjacent set of chambers 62 , 64 . As such, the combination reaction vessel provides a staged exothermic reaction process (preferably combustion of a fuel) to provide a uniform temperature profile and heat transfer to drive an endothermic reaction (preferably a fuel reforming process) occurring in an adjacent chamber.
Referring now to FIG. 6 , another embodiment of the present invention includes a combination reaction vessel 54 having a plurality of spaced apart, parallel endothermic reaction chambers 62 . In this case the endothermic reaction chambers 62 are vertically spaced apart and separated by an exothermic reaction chamber 64 that has a longitudinal axis and flow path running in a perpendicular direction to the longitudinal axis and flow path of the endothermic reaction chamber 62 . However, parallel co-flowing and counter flow configurations are contemplated as a part of the present invention. As described earlier, an endothermic reaction catalyst is provided in each of the endothermic reaction chambers 62 and the endothermic reactants, such as a methanol/water, gasoline/water vapor mixture, or other fuel/water mixture are supplied through one end 72 (see also FIG. 3 ) of the endothermic reaction chamber and flow in the direction indicated by arrow shown entering the reaction chamber 62 in FIG. 6 .
A plurality of spaced apart parallel exothermic reaction chambers 64 are provided so that each exothermic chamber 64 separates two endothermic reaction chambers 62 so as to provide a staged exothermic reaction process. The exothermic chambers 64 may also be arranged in a laterally adjacent side-by-side configuration. An inlet header 86 is provided having an inlet opening 88 formed therein through which at least one of the exothermic reactants is charged to the exothermic reaction chambers 64 . Preferably, exhaust gas (which contains oxygen) from the cathode side of the fuel cell is feed through the inlet opening 88 . The cathode exhaust gas flows down a first set of exothermic reaction chambers and is directed by a flow directing header 90 down a second set of exothermic reaction chambers, and so on in a serpentine fashion throughout the combination reaction vessel 54 and finally exits through an exhaust opening 92 formed in an outlet header 94 .
A second exothermic reaction reactant may be charged into the exothermic reaction chambers 64 utilizing a charge manifold. 96 . In a preferred embodiment, the charge manifold 96 includes a plurality of charge pipes or lines 82 . A charge pipe 82 is received in one of each of the exothermic reaction chambers 64 . Preferably, the charge pipe 82 has a plurality of discharge holes 84 which are spaced apart along the length of the exothermic reaction chamber (as also shown in FIG. 5 ). The combination reaction vessel 54 may be constructed and arranged so that the charge pipes 82 also function to separate laterally adjacent side-by-side exothermic reaction chambers. That is, the charge crepe 82 acts as a wall separating laterally adjacent exothermic reaction chambers. Because the exothermic reaction chambers 64 are staged in sections and at least one reactant is selectively and/or uniformly charged to each chamber along the length of the exothermic chamber, the heat generated throughout the exothermic reaction chamber may be controlled so that it is substantially uniform, or graduated if so desired. Consequently, the heat transferred to the endothermic reaction chamber, catalyst and reactants is such that the temperature profile in the endothermic reaction chamber is controlled to be substantially uniform, or graduated if so desired. Maintaining a controllable temperature profile in a fuel reforming process is important to avoid undesirable side effects such as catalyst degradation, or methane slip. At low power, the temperature profile may be such as to promote a high temperature reformation with a high temperature shift reaction at the exit of the reaction chamber. The temperature at the exit end of the reaction chamber should be high enough to suppress methane formation for a given catalyst.
A plurality of temperature or concentrations sensors 104 may be selectively placed in the combination reaction vessel, and valves 100 may be included in the charge manifold 96 to selectively control the amount of reactant being charged to the chamber and thus control the reaction as desired. Associated on-board computer controllers 102 , drivers and associated electrical equipment can be provided to control the above described components and processes in a manner known to those skilled in the art.
For example, in a methanol reformer, the charge manifold 96 may be constructed and arranged to controllably charge reactants so that a uniform temperature profile at full power is provided which would utilize the entire reactor volume. However, under turndown situations (for example, when the vehicle is stopped), less power is required, and thus only a portion of the reactor is required to reform fuel because of the lower-power demand. In these turndown situations it may be desirable to control the exothermic reaction adjacent to each endothermic reaction chamber section so that only selected endothermic reaction chamber sections or portions of selected endothermic reaction chambers sections are provided with enough heat to reform fuel. The remaining endothermic reaction sections or portions thereof could be utilized to perform a water gas shift reaction to reduce the concentration of CO in the fuel reforming stream. For example, the temperature in the first two endothermic reaction sections could be controlled to provide relatively high temperature fuel reforming and the temperature in the remaining endothermic reaction sections (that is, in the rearward portion of the reaction vessel) could be controlled to be relatively low thereby reducing unwanted reformation byproducts and so that a maximum conversion is accomplished during the fuel reforming while minimizing methane slip.
In another embodiment, illustrated in FIG. 7 , the vaporizer may be included in the front portion of the combination reaction vessel 54 . The combination reaction vessel shown in FIG. 7 operates similarly to the vessel shown in FIG. 2 , but with a few exceptions. In this embodiment, a fuel/water mixture may be charged through line 258 into a first section of the combination reaction vessel 54 to be vaporized in a first heat exchanger section 202 . The fuel/water mixture flows through a plurality of spaced apart chambers 262 ′ that do not include a fuel reforming catalyst. Thereafter, the endothermic reaction chambers 262 include a fuel reforming catalyst as previously discussed.
The fuel/water mixture entering the chambers 262 ′ is vaporized by heat generated by the catalytic combustion of a combustion fuel mixture charged into a plurality of exothermic reaction chambers 264 . An oxidant or fuel, preferably an oxidant such as oxygen from the fuel cell stack effluent, may be charged to the exothermic reaction chambers 264 through a charge line 242 and header 243 . An oxidant or fuel, preferably a fuel such as hydrogen from the fuel cell stack effluent, is charged to the exothermic reaction chambers 264 through charge line 282 . A combustion fuel mixture travels through the plurality of spaced apart exothermic reaction chambers 264 generating heat to vaporize the fuel/water mixture or reform the fuel/water mixture. Preferably one of the oxidant or fuel is charged to the exothermic reaction chambers 264 through charge lines 282 in a staged fashion as previously discussed. However, in this embodiment, the exothermic reaction chambers 264 to are spaced apart vertically and horizontally so that a partition section 299 is provided between laterally spaced apart exothermic reaction chambers 264 . The partition sections 299 provide for staged adiabatic reformation of the fuel/water mixture. If desired, the catalyst loading in different portions of the endothermic reaction chambers 262 may be varied as desired. That is, the catalyst loading may be graded throughout the reforming sections. The combination reaction vessel 54 may include flow directing headers 190 to directing the flow of exhaust exiting the first set of exothermic reaction chambers 264 so that it enters a second set of exothermic reaction chambers that are spaced a distance from the first set. The combustion reaction exhaust exits the vessel through line 245 in the reformation reaction exhaust exits the vessel through line 256 . | A reaction vessel that integrates and balances an endothermic process with at least one exothermic process of the fuel cell system. Preferably the exothermic process is conducted in stages to provide more uniform and/or controllable heat generation and exchange, and to produce a uniform and/or controllable temperature profile in the endothermic reaction process. The invention allows for the elimination of the working fluid loop of prior art systems that had unsatisfactory response times at startup, and during transient conditions, and also added to the overall mass and volume of the fuel cell system. | 2 |
CROSS-REFERENCES TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. 119(a) to Korean application No. 10-2014-0031047, filed on Mar. 17, 2014, in the Korean intellectual property Office, which is incorporated by reference in its entirety as set forth in full.
BACKGROUND
[0002] 1. Technical Field
[0003] Various embodiments of the inventive concept relate to a method for fabricating a semiconductor apparatus, and more particularly, to a method for fabricating a semiconductor apparatus including a uniform metal silicide layer having a thin thickness.
[0004] 2. Related Art
[0005] The penetration rate of digital apparatuses is increasingly growing and there are demands for memory devices with ultra-high integration, ultra-high speed, and ultra-low power, which are built in digital apparatuses in order to process large amounts of data at high speed in a limited area.
[0006] To meet the demands, variable resistive memory devices using a resistance material as a memory medium have been suggested. Typical examples of variable resistive memory devices are ferroelectric random access memories (FRAMs), magnetoresistive RAMs (MRAMs), or phase-change RAMs (PCRAMs).
[0007] A variable resistive memory device may be typically formed of a switching device and a resistance device, and may be implemented with a single-level cell (SLC) or a multi-level cell (MLC).
[0008] In particular, PCRAM includes a phase-change material layer which is stabilized to either a crystalline state or an amorphous state by heat, and switched between the two different resistance states.
[0009] Hereinafter, a general structure of a PCRAM will be described with reference to the accompanying drawings.
[0010] The PCRAM has a structure in which a switching device layer, an ohmic contact layer, a lower electrode, a phase-change material layer, and an upper electrode are sequentially formed on a semiconductor substrate.
[0011] The ohmic contact layer in the PCRAM structure is provided to reduce the electric contact resistance between the switching device layer and the lower electrode, and may generally include a metal silicide layer.
[0012] The metal silicide layer may be formed through a physical vapor deposition (PVD) method or a direct current plasma-assisted chemical vapor deposition (CVD) method.
[0013] A metal silicide layer produced through the PVD method may be formed by thickly depositing a metal layer, and performing a post-heat treatment process on the metal layer. However, the post-heat treatment makes it difficult to form a uniform metal silicide layer.
[0014] When the metal silicide layer is formed through the direct current plasma-assisted CVD method, the metal is grown by a vapor reaction and simultaneously the metal silicide layer is formed by a reaction with the silicon (Si) surface. As the metal reaction is increased by plasma or high-temperature deposition, the direct-current plasma-assisted CVD method makes it difficult to form a uniform metal silicide layer due to poor step coverage.
SUMMARY
[0015] According to an exemplary embodiment of the present invention, a method for fabricating a semiconductor apparatus including an ohmic contact layer is provided. The method may include setting a semiconductor substrate in a process chamber, increasing the internal temperature of the process chamber to a predetermined temperature for pyrolyzing a source gas, remaining pyrolyzed ions of the source gas on the semiconductor substrate by supplying the source gas to the inside of the process chamber and pyrolyzing ions of the source gas, and forming the ohmic contact layer by supplying a reaction gas to the inside of the process chamber and supplying an inert gas to the process chamber to form a plasma atmosphere, wherein the reaction gas is reacts with non-metal ions pyrolyzed from the source gas in a plasma atmosphere.
[0016] According to an exemplary embodiment of the present invention, a method for fabricating an ohmic contact layer on a switching device layer of a phase changeable random access memory (PCRAM) is provided. The method may include providing a chemical vapor deposition (CVD) chamber, setting a substrate on which the switching device layer is formed in the CVD chamber, increasing the temperature of the CVD chamber to a first temperature, supplying a source gas including a metal material and other materials to the CVD chamber, wherein the source gas is pyrolyzed by the first temperature of the chamber, supplying a reaction gas and an inert gas to the CVD chamber, wherein the reaction gas reacts with the other materials on the switching device to be removed therefrom, and purging the inside of the chamber using a purge gas.
[0017] According to an exemplary embodiment of the present invention, a method for fabricating a semiconductor apparatus is provided. The method may include supplying a source gas including a metal material at a predetermined temperature to a semiconductor substrate in a chamber and depositing the source gas on the semiconductor substrate, and removing materials deposited on the semiconductor substrate other than the metal material by reacting a reaction gas with deposited materials.
[0018] These and other features, aspects, and embodiments are described below in the section entitled “DETAILED DESCRIPTION”.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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:
[0020] FIG. 1 is a schematic cross-sectional view illustrating a semiconductor apparatus according to an embodiment of the inventive concept;
[0021] FIG. 2 is a flowchart illustrating a method for fabricating a semiconductor apparatus according to an embodiment of the inventive concept;
[0022] FIG. 3 is a schematic diagram illustrating fabrication equipment where an ohmic contact layer fabrication method of a semiconductor apparatus is performed according to an embodiment of the inventive concept; and
[0023] FIG. 4 is a waveform diagram illustrating a supply pattern of process gas in a fabrication method of a semiconductor apparatus according to an embodiment of the inventive concept.
DETAILED DESCRIPTION
[0024] Exemplary embodiments are described herein with reference to schematic illustrations of exemplary embodiments (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 embodiments should not be construed as limited to the particular shapes illustrated herein but may include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and widths of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. It is also understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other or substrate, or intervening layers may also be present. It is also noted that in this specification, “connected/coupled” refers to one component not only directly coupling another component but also indirectly coupling another component through an Intermediate component. In addition, the singular form may include a plural form, and vice versa, as long as it is not specifically mentioned.
[0025] The inventive concept is described herein with reference to cross-section and/or plan illustrations of embodiments of the inventive concept. However, embodiments of the inventive concept should not be construed as limiting the inventive concept. Although a few embodiments of the inventive concept will be shown and described, it will be appreciated by those of ordinary skill in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the inventive concept.
[0026] Hereinafter, an exemplary embodiment of the inventive concept, for example, a PCRAM will be described. FIG. 1 illustrates a semiconductor apparatus according to an embodiment of the inventive concept.
[0027] Referring to FIG. 1 , a semiconductor apparatus 10 according to an embodiment of the inventive concept may include a switching device layer 120 formed on a semiconductor substrate 110 , an ohmic contact layer 130 formed on the switching device layer 120 , a lower electrode 140 formed on the ohmic contact layer 130 , a phase-change material layer 150 formed on the lower electrode 140 , and an upper electrode 160 formed on the phase-change material layer 150 .
[0028] The ohmic contact layer 130 in a structure of the semiconductor apparatus 10 is provided to reduce electrical resistance between the switching device layer 120 and the lower electrode 140 . The ohmic contact layer 130 may be provided to cover an upper surface and a sidewall of the switching device layer 120 which is formed on the semiconductor substrate. The switching device layer 120 may have a pillar structure and include a silicon material. This is because the ohmic contact layer 130 increases the contact area with the lower electrode 140 to reduce contact resistance with the lower electrode 140 , and to increase an ON current due to reduction in the contact resistance.
[0029] The ohmic contact layer 130 may include a metal silicide layer. For example, the ohmic contact layer 130 may be formed of a titanium silicide layer.
[0030] The reference numerals 111 , 113 , and 115 denote a gate insulating layer, a gate electrode, and an inter-dielectric layer, respectively.
[0031] A process for forming an ohmic contact layer of a semiconductor apparatus according to an embodiment of the inventive concept will be described with reference to FIGS. 1 to 3 .
[0032] First, the semiconductor substrate 110 including the switching device layer 120 is arranged in a process chamber 20 (S 110 ). The process chamber 20 may be a chemical vapor deposition (CVD) chamber.
[0033] Next, in the temperature is raised in the process chamber 20 (S 120 ). For example, the inside of the process chamber 20 may be set to a temperature of 450° C. to 1000° C. at a rate of 5 to 20° C./sec. The temperature may be a pyrolyzing temperature of a source gas for forming a metal silicide layer. Further, the pressure of the process chamber 20 may be about 0.5˜20 Torr.
[0034] The source gas G 1 is supplied to the inside of the process chamber 20 for through a first pipe L 1 (S 130 ). The source gas G 1 may be selected from the group consisting of gases containing a metal precursor and an organic metal precursor. For example, the source gas G 1 may be TiCl 4 gas, and may be provided to the inside of the process chamber 20 at a flow rate of 1 to 1000 sccm.
[0035] When the source gas G 1 is supplied as a high-temperature environment is created in the process chamber 20 as described above, a precursor of the source gas G 1 may be pyrolyzed into metal ions and non-metal ions inside of the process chamber 20 , and the metal ions and non-metal ions may be deposited on the switching device layer 120 . For example, when the source gas G 1 includes TiCl 4 gas, Ti metal ions and Cl ions may be pyrolyzed and absorbed on the semiconductor substrate 110 having the switching device layer 120 .
[0036] Next, a reaction gas G 2 is supplied to inside the process chamber 20 for a given time through a second pipe L 2 (S 140 ), and simultaneously a plasma atmosphere is created in the process chamber 20 (S 150 ). The reaction gas G 2 may Include at least one selected from the group consisting of H 2 gas, NH 3 gas, and F gas.
[0037] The reaction gas G 2 may react with one of the ions remaining on the semiconductor substrate 110 in the plasma atmosphere. For example, when the reaction gas G 2 includes H 2 gas, the H 2 gas may react with Cl ions (Cl − ) remaining on the semiconductor substrate 110 in the plasma atmosphere, and the Cl ions may be removed. Only non-reacted Ti metal ions are left on the semiconductor substrate 110 .
[0038] In the above-described process, to create the plasma atmosphere in the process chamber 20 , an inert gas G 3 may be supplied through a third pipe L 3 . The inert gas G 3 may include one selected from the group consisting of Ar, He, Ne, Kr, Xe, and Rn gas.
[0039] The Cl ions reacted with the reaction gas G 2 , that is, HCl gas and the inert gas G 3 may be vented by continuously pumping them out of the process chamber 20 .
[0040] Next, a purge gas G 4 is supplied to inside of the process chamber 20 through a fourth pipe L 4 (S 160 ). When the purge gas G 4 is supplied, a reduction in temperature inside the process chamber 20 may occur.
[0041] The above-described sequences S 120 to S 160 may suppress a vapor reaction of the reaction gas G 2 and the source gas G 1 and react the reaction gas G 2 with non-metal ions (Cl ions) of the source gas G 1 on a surface of the semiconductor substrate 110 to uniformly form a metal silicide layer (Ti metal ions) on the semiconductor substrate 110 including the switching device layer 120 .
[0042] Referring to FIGS. 2 and 4 , a thin metal silicide may be smoothly formed by repeatedly performing the above-described sequences. That is, when the sequences S 120 to S 160 are defined as one cycle, the metal silicide layer having a predetermined thickness may be formed by repeatedly performing the cycle.
[0043] For example, when a process of forming a metal silicide layer having a thickness of 10 Å is defined as one cycle, 10 cycles may be repeatedly performed to form a metal silicide layer with a thickness of 100 Å. In the embodiment, a process of forming a thin metal silicide layer may be repeatedly performed to form a uniform metal silicide layer having a predetermined thickness.
[0044] As described above, in the embodiment, ions of the source gas G 1 are deposited on the semiconductor substrate 110 by pyrolyzing the source gas G 1 in the process chamber 20 at high temperatures, and the uniform metal silicide layer may be formed using the metal ions deposited on the semiconductor substrate 110 by reacting the reaction gas G 2 with the deposited non-metal ions in a plasma atmosphere.
[0045] The embodiment may smoothly form a thin but uniform metal silicide layer having a predetermined thickness by repeatedly performing the above-described process.
[0046] The above embodiment of the present invention is illustrative and not limitative. Various alternatives and equivalents are possible. The invention is not limited by the embodiments 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. | A method for fabricating a semiconductor apparatus includes setting a semiconductor substrate in a process chamber, increasing an internal temperature of the process chamber to a predetermined temperature for pyrolyzing a source gas, supplying the source gas to the inside of the process chamber and pyrolyzing ions of the source gas to remain on the semiconductor substrate, and forming the ohmic contact layer by supplying a reaction gas to the inside of the process chamber, wherein the reaction gas is reacted with non-metal ions pyrolyzed from source gas. | 7 |
REFERENCE TO RELATED PATENT APPLICATIONS
This patent application is a continuation of patent application Ser. No. 197,895 filed Oct. 17, 1980 (now abandoned); which in turn is a continuation of patent application Ser. No. 965,908 filed Dec. 4, 1978, now U.S. Pat. No. 4,262,410.
BACKGROUND OF THE INVENTION
When pipe is transferred from one geographical location to another, the threads thereof must be protected against damage which might result from handling and from the deleterious effects of the ambient. Oilfield pipe, especially drill pipe and production tubing, may be handled many times during its life, and the removal and replacement of the thread protectors at each end of the pipe joints requires a substantial amount of labor.
When the joints of pipe are transferred longitudinally along the axial centerline thereof; for example, as the pipe is being manufactured, or as the pipe is being electronically inspected; the ends of the pipe are disposed such that ready access may be had to the protector device located on either end thereof. It would therefore be desirable to be able to economically and efficiently remove or attach the protectors on either end of the pipe, as the pipe is being conveyed during either of these processes.
It would also be desirable to clean the threaded box and pin ends of the pipe during the above process, and thereafter measure the uniformity of the interior of the pipe to assure that the inside diameter is of a minimum value.
Such a desirable expedient is the subject of this invention.
SUMMARY OF THE INVENTION
A tool for rotating co-acting threaded members to enable the members to be made up and broken out respective to one another. The tool comprises a plurality of circumferentially spaced-apart jaw means for releasably engaging and rotating one of the co-acting threaded members.
A first and a second plurality of arm members are arranged for moving the jaw means radially towards one another and into gripping contact with the threaded member. The arm members are attached to first and second rotatable mount members which impart rotational motion into the jaw members. The first and second rotatable mount members are movable towards and away from one another.
One end of each arm member is journaled to one of the jaw means. The other end of the first plurality of arm members is journaled to the first rotatable mount member, while the other end of the second plurality of jaw members is journaled to the second rotatable mount member. The first and second rotatable members are mounted to the marginal end of a motor-driven rotatable shaft, with the first mount member being arranged to be reciprocated along a marginal, medial portion of the shaft. Means attached to structure associated with the motor moves the first rotatable member towards and away from the second rotatable member, thereby causing the arms to move the jaws toward and away from one another.
In a more specific form, the first plurality of arms are arranged such that parallel pairs of arms have the ends thereof connected between the second mount member and the jaws, thereby causing the jaws to remain orientated in the same direction as the jaws move toward and away from one another. Another arm interconnects the jaws to the first rotatable member so that movement between the first and second rotatable members imparts pivotal motion into the parallel arms.
In another embodiment of the invention, the main frame is connected to be moved laterally away from the longitudinally traveling pipe and then the tool is rotated 180° in a vertical plane which lies along the longitudinal axial centerline of the pipe. The tool is thereby repositioned to engage and remove the remaining protector from the pin end of the pipe.
In still another embodiment of the invention, a cleaning head is mounted in cooperative relationship respective to the main frame with the cleaning head being axially aligned with the end of one pipe while the jaws of the tool are aligned with the end of an adjacent pipe. The cleaning head engages and cleans the threads of one pipe end simultaneously with the removal of a protector device from the end of an adjacent pipe.
In still a further embodiment of the invention, a gauging tool is positioned to be telescopingly received within a pipe as the pipe travels away from the tool, thereby assuring that the pipe interior is of a predetermined minimum value.
Accordingly, a primary object of the present invention is the provision of apparatus for rotating co-acting threaded members to enable the members to be made up and broken out respective to one another.
A further object of the present invention is the provision of method and apparatus by which couplings and pipe protectors and the like may be removed from or threadedly made up to the end of a joint of pipe while simultaneously cleaning the threaded pipe ends.
A still further object of this invention is the provision of a machine for releasably engaging and turning a threaded member.
Another and still further object of the present invention is the provision of method and apparatus by which a threaded member can be removed from either end of a joint of pipe, while another threaded end of a pipe is being cleaned.
An additional object of this invention is the provision of an apparatus for removing pipe protectors from the threaded ends of a joint of pipe.
A further object of this invention is the provision of a machine having a shaft-mounted, rotating head assembly with radially-spaced jaws being moved toward and away from one another by manipulation of the head assembly so that the jaws can releasably engage and rotate a rotatable member.
These and various other objects and advantages of the invention will become readily apparent to those skilled in the art upon reading the following detailed description and claims and by referring to the accompany drawings.
The above objects are attained in accordance with the present invention by the provision of a combination of elements which are fabricated in a manner substantially as described in the above abstract and summary.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 diagrammatically sets forth a flow sheet which illustrates one form of the utility of the present invention;
FIG. 2 is a part diagrammatical, part schematical, side view of apparatus made in accordance with the present invention, with some parts being broken away therefrom in order to better disclose the details thereof;
FIG. 3 is a top perspective view which further illustrates the details of the apparatus disclosed in FIG. 2;
FIG. 4 is a perspective, exploded detail of part of the machine illustrated in the foregoing figures;
FIG. 5 shows the apparatus of FIG. 4 in assembled configuration;
FIGS. 6 and 7 are partially disassembled, perspective views of part of the apparatus located on the opposite side of the apparatus disclosed in FIG. 5;
FIG. 8 is a front perspective view of part of the apparatus disclosed in FIGS. 2 and 3;
FIG. 9 is a rear perspective view of part of the apparatus disclosed in FIG. 3;
FIGS. 10 and 11 are enlarged, fragmented, perspective views illustrating the operation of part of the apparatus disclosed in some of the foregoing figures;
FIG. 12 is a front plan view which is similar to the illustration of FIG. 8;
FIG. 13 is a diagrammatical illustration of another form of the present invention;
FIG. 14 is a detailed, side elevational view of part of the apparatus seen in FIG. 13;
FIG. 15 is a cross-sectional view taken along line 15--15 of FIG. 14; and,
FIG. 16 is a cross-sectional view taken along line 16--16 of FIG. 14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiment of FIG. 1, the tool 10 of the present invention is seen to be positioned such that it obstructs a continual flow of longitudinally aligned pipe 12 traveling to or from a pipe rack 11. Pipe protectors are placed on opposed pipe ends 13 and 14.
The tool engages end 13 of the pipe to remove a protector therefrom. The tool is mounted to be moved along track 72 laterally away from the pipe as seen at 10', thereby enabling the pipe 12' to be conveyed past the tool. The tool is rotated 180° and repositioned at 10" to engage the other end 14 of the pipe at 12".
As seen in FIG. 2, the tool 10 includes an air motor 15 and is provided with a conventional gear reducer which drives a shaft 16. The shaft may be splined, as for example, an SAE 10 spline shaft, or may be square as noted in the drawings. A rotating head assembly 17 is provided for releasably gripping one of the two coacting threaded members of the pipe, such as pipe thread protectors or pipe couplings, in order that the coacting threaded members may be made up and broken out respective to one another. The threaded member illustrated herein is the before mentioned pipe and pipe protector.
As seen in FIGS. 2 and 3, a first mount member, in the form of a large mount plate 19, is spaced from a second mount member in the form of a small mount plate 18. A traveling bearing means 20 is affixed to a non-rotating mount member 21. The mount member is reciprocatingly moved in a slidable manner respective to the rotatable shaft and with respect to structure 22, which forms part of the main frame of the tool.
The motor is suitably mounted within the framework 22 and supported by a base 23. The base includes a lug 24 by which the entire machine can be rotated within a vertical plane and about an axis lying normal to the longitudinal axis of the shaft and pipe, thereby positioning the tool in either of the illustrated positions 10 or 10" of FIG. 1.
As seen in FIGS. 2, 3, and 9, spaced hydraulically-actuated cylinder assemblies include a piston 25 having the free end thereof attached to opposed sides of the reciprocating, non-rotatable mount member 21, while the cylinders 26 thereof are attached to a stationary plate 35, with the last named plate being attached to the main frame member 22. Hence, the hydraulic cylinders are mounted to move plate members 21 and 35 toward and away from one another as best seen illustrated in FIGS. 2 and 9.
As best seen in FIGS. 10 and 11, together with other figures of the drawings, one of a plurality of claw and arm assemblies 27 form the forward part of the rotating head assembly. The claw assembly includes a plurality of radially spaced jaws 28 to which there is connected an actuating arm 29 and a pair of idler arms 30, also hereinafter referred to as a first and a second plurality of arms.
As seen in FIGS. 6, 7, 8, and 12, in conjunction with other figures of the drawings, a block 31 is bolted onto one side of the plate 19 in spaced relationship to other similar blocks which are circumferentially spaced about the outer marginal, peripheral edge portion of the plate. Each block accepts a pin 32, thereby forming a journal means for one end of each of the before mentioned arms 29. It will be noted that arm 29 in the figures of the drawings comprises a pair of arms positioned on either side of the jaw and block, and the pair of arms are considered to fall within the comprehension of "an arm". The opposed end of arm 29 is journaled to the jaw at 33. The parallel arms 30 are journaled to the jaw at 33 and 34 with pin 33 being mutually shared by the outer end portion of arms 29 and 30.
As seen in FIGS. 2, 3, and 9, a bearing means 37 is supported from the before mentioned plate member 35 in spaced relationship respective to the traveling bearing housing 20. Bearing housing 37 includes a rotating inner bearing part 44. Coupling 38 interconnects the gear reduction output shaft to the square drive shaft 16.
Looking now to FIGS. 4-8, which disclose the details of the large plate member 19 and the associated slidable bearing housing 20, there is seen a hub member 39 which is affixed to plate 19 and which slidably receives a medial marginal length of the power output shaft 16. Bearing 40 admits low friction turning between the shaft and the outer housing 36 of the bearing means. In FIGS. 4 and 5, apertures 41 are placed 120° apart for receiving block 31. FIG. 6 discloses the opposed side of the large plate member and the location of the blocks 31.
As seen in FIGS. 3, 7, and 8, the small plate member 18 is similarly provided with radially spaced blocks 42 so that the parallel arm assemblies can be journaled thereto.
In operation, the apparatus 10 for removing protective members from the threaded ends 13 and 14 of pipe joints 12 comprises a main frame member 22 to which a motor 15 is affixed to enable the shaft 16 to be rotated. The shaft has a splined connection at 39. The term "splined shaft" is intended to denote "a shaft having an irregular outer surface area", as for example, the illustrated square shaft.
The square shaft imparts rotation into a first mount member 19, which is illustrated as being in circular form, and which can assume other geometrical configurations, so long as the radially spaced-apart actuating arms 29 are attached to and move therewith. The first mount member is slidably supported on the shaft. A second mount member 18, which is illustrated as being of a circular configuration, but which can take on several different forms so long as the central axis thereof is attached to the terminal end of the power output shaft and moves therewith.
The arms 30 are arranged in spaced parallel pairs to provide four arms for each jaw. The arms have one of the opposed ends thereof journaled to the second mount member and the other end journaled to the jaw. The actuating arm members 29 are pivotally connected to the innermost pivot pin of the jaw; and therefore, a common pin ties one end of the arms 29 and one end of one pair of the arms 30 to the jaw.
As the second member 18 is moved towards and away from the first member 19, the jaws move towards and away from one another, and the parallel relationship of the pairs of arms 30 maintain the jaw orientated in the same general direction as the jaws move towards and away from one another.
In the illustrated embodiment of FIG. 1, the apparatus is moved on a laterally disposed track, with the jaws concentrically arranged respective to the axial centerline of the pipe 12. The hydraulic cylinders 26 force the pistons 25 to extend therefrom, thereby moving the first mount member 19 towards the second mount member 18 to close the jaws about the protector. The air motor 15 is supplied with a suitable source of compressed air for causing the power shaft to rotate the entire head assembly, which rotates the pipe protector therewith, thereby removing the protector from the pipe end. The piston is next retracted within the cylinder, thereby moving plate members 18 and 19 apart, which cause the jaws to move radially away from one another, whereupon the protector is released and may be dropped onto a moving conveyor (not shown) located below the pipe.
The apparatus 10 moves laterally away from the pipe 12, 12', so that the pipe can continue at 12' on to station 12" as the apparatus is pivoted at 24 from the position seen at 10 into a second position 10". The apparatus 10' is repositioned at 10" into axially aligned relationship respective to the pipe so that the rotating head assembly can engage and remove the remaining protector from the other end of the pipe.
In the embodiment of the invention illustrated in FIG. 13, pipe 12 is stored on pipe rack 11 and conveyed at 12' toward a tool 110 made in accordance with the present invention. The tool 110 includes apparatus 10 made in accordance with the first embodiment of the invention, and additionally includes a thread cleaning apparatus 80 mounted on the same framework therewith. The tool 10 removes a pipe protector form pipe end 13 while the tool 80 is cleaning the threads at pipe end 14' and vice versa. The apparatus 110 can be retracted away from the line of travel of the pipe as the pipe moves from 12' to 12". The apparatus 110 is rotatable 180° in a vertical plane in order to reverse the relationship of the tools 10 and 80.
After the protectors have been removed from each end of the pipe, and the threads have been cleaned, the pipe continues along its longitudinal axial centerline causing a drift indicator 81 to telescopingly receive the pipe thereabout as indicated by numeral 12"'. Numeral 82 indicates a cantilever arm which supports the drift apparatus 81 in a manner to enable the apparatus to travel along the entire length of the pipe. Apparatus 81 is a commercially available drifting device which determines the minimum inside diameter of the pipe.
After the pipe has been drifted, it is returned to position 12" and then moved laterally onto pipe rack 111.
In FIG. 14, the tool 10 is schematically illustrated mounted on main framework 22 as in the before described manner of FIGS. 1-12. Apparatus 24 rotates the entire framework to describe a vertical plane which lies along the longitudinal axial centerline of pipe 12', 12", 12"'. Hence, the tools 10 and 80 change their relative position in order that each tool can sequentially work on each end of the pipe in the above described manner.
As seen in FIG. 14, the cleaning tool 80 includes a hydraulically actuated motor 83 which concurrently rotates plate members 84 and 85 about the centers thereof. Motor support 86 rotatably mounts motor 83 to the main frame so that when shaft 87 is rotated 180° by motor 88, plate members 84 and 85 change their relative positions. Stated differently, shaft 87 is rotatably received within housing 86 and rotates motor 83 within a plane which coincides with the axial centerline of pipe joints 12' and 12". The centers of plates 84 and 85 are axially aligned and coincide with the center of the shaft of tool 10 when the cleaning tool 80 is in either of the above described alternant positions.
Radially spaced brushes 89 are adjustably affixed to and extend from the outer face of plate member 85, while radially spaced brushes 90 are adjustably affixed to the outer face of plate member 84. The outer faces of the plates are diametrically opposed to one another.
As seen in FIG. 14, the motor 83 has opposed shaft ends, one of which is seen at 91 in FIG. 15. Radially arranged slots 92 adjustably receive the brush members 90. A fastener means 93 is received through the slot by which the brushes 90 is fastened to the plate member 84 along any desired circumference measured radially from the shaft 91. The cleaning surface 97 of the brushes 90 is arranged to frictionally engage the inside threaded wall surface 97' of the end of a pipe joint; that is, the box end of the pipe joint.
In FIG. 16, the radially spaced brushes 89 are adjustably attached to plate member 85 by means of fastener 95 received through radially arranged slot 94. The brushes may be moved toward and away from one another to position the cleaning surface 96 thereof along a circumference 96' so that the cleaning surface of the brushes can frictionally engage the outer threaded surface of a pipe joint; that is, the pin end of the pipe joint.
In operation, joints of pipe are racked at 11 and transferred in series relationship by a conventional conveyor system towards the apparatus 110. The tool 10 engages the pipe protector at pipe end 13, unscrews the protector, and drops it onto an underlying moving conveyor (not shown). The pipe ends are moved apart, the tool 110 reversed 180°, the pipe ends are moved towards one another, whereupon the tool 10 engages the protector at pin end 14', and the protector is dropped onto the conveyor.
Simultaneously with the removal of the protector from pipe end 14', the cleaning tool 80 engages and cleans the threads of pipe end 13. The tool 110 is again rotated 180° and the remaining end 14' is cleaned.
After the protectors are removed and the threads of the pipe ends have been properly cleaned, the apparatus 110 moves laterally away from the longitudinal axial centerline of the pipe supported upon the conveyor, and the pipe 12" is moved by the conveyor to telescopingly receive the drifter 81 to assure that the inside diameter is of a minimum value. The pipe is moved from 12"' back to position 12" and then moved laterally onto the pipe rack 111. Meanwhile, pipe 12 and 12' are positioned at 12' and 12".
Each time the main frame 22 is rotated 180° by apparatus 24, shaft 87 is simultaneously rotated 180° to change the operative relationship of the brushes 89 and 90 respective to one another. Thus, the cleaning device of the apparatus 110 is repositioned to properly receive the box or pin ends of the next adjacent joint of pipe.
It is considered within the comprehension of the present invention to utilize the action of apparatus 24 rotating the main frame 180° in order to impart 180° of rotation into shaft member 87. This can be achieved by a stationary sprocket associated with rigid structure adjacent to motor 24, or alternatively, linkage and bell cranks can be connected to achieve 180° of rotational motion of shaft 87 each time the main frame is rotated by apparatus 24.
Moreover, it is considered within the comprehension of this invention to utilize a drive train from the motor of tool 10 in order to rotate shaft ends 91 and 98 of the cleaning tool 80.
The apparatus of the present invention enables a single operator to remove threaded members from the ends of pipe, clean the threaded ends of the pipe, drift the interior of the pipe, and thereafter move the pipe to a storage rack. | A tool having opposed cleaning heads for sequentially engaging and cleaning the opposed threaded ends of pipe joints. A pipe end is engaged and cleaned by a brush located on one of the cleaning heads. The pipe is moved longitudinally to position the remaining threaded end near the other cleaning head. The tool is manipulated to position the other cleaning head in contact with the remaining threaded end so that both the box and pin end of a pipe joint can be rapidly and efficiently cleaned. | 8 |
TECHNICAL FIELD OF THE INVENTION
[0001] This invention refers to an air system for tractors used in drawing farm equipments, agricultural machinery such as combine harvesters, crop-sprayers, sowers, hoppers, grain augers, trailers, carts, towing vehicles to support and transport different kinds of cargos such as cereals.
DESCRIPTION OF THE PRIOR ART
[0002] Nowadays, it's widely known that agriculture machines such as tractors lack air brakes and a system able to produce air which is eventually used by other devices, such as hoppers, towing vehicles, agro-industrial tractors or pulling trailers which may need pneumatic pressure in the break system.
[0003] The brakes system of this invention will produce compressed air in order to be eventually applied to combines harvesters, tractors, crop sprayers, sowers or any devices. This equipment will require the use of compressed air while sowing (sower), field spraying (crop sprayer) and harvesting (combine harvester).
[0004] The brakes system of the present invention will also be used in grain augers of large and medium size, as well as in all size hoppers, trailer harvesters, and agro industrial carts. This is a safe, clean and non-polluting air brakes system which allows the supply of compressed pneumatic pressure in the machinery and/or the vehicles previously mentioned.
SUMMARY OF THE INVENTION
[0005] The purpose of this, invention is to generate, control, minimize and maximize air pressure by means of interrelations and relations of different pneumatic groups and subgroups.
[0006] The pneumatic pressure generated by the system will be used when the pneumatic suspension is applied to the specified vehicle.
BRIEF FIGURES DESCRIPTION
[0007] The invention has been illustrated in terms of three different figures in order to make a clear description of its elements and devices.
[0008] FIG. 1 : It illustrates the elements distribution in terms of a simple pneumatic brakes circuit.
[0009] FIG. 2 : It illustrates the elements distribution in a dual pneumatic brakes circuit.
[0010] FIG. 3 : It illustrates a double pneumatic brakes circuit where sensitive valves to cargo as well as valves to control trailers have been added
DETAILED DESCRIPTION OF THE INVENTION
[0011] As shown in FIG. 1 , the simple brakes circuit consists of an air compressor 1 , where the compressed air is generated. This device takes air in through a separate filter, the air is compressed, and either sent to the brakes system or stored it in air tanks under a certain pressure. The compressor runs by means of gears placed inside the compressor's engine distribution, by pulleys and drive belt which are adjusted to the cram shaft movement and/or gimbals of irregular rotation or by gimbals of irregular movements. Its refrigeration can be achieved with water, oil or air. The compressor's engine may consist of one or two cylinders and its lubrication may be produced by the engine itself or by the oil pressure within the engine. A spiral pipe 2 will be placed so as to cool the air, a flexible joint 3 will be included to prevent the bodywork and the engine from moving. At the same time, the engine connects the spiral pipe to the air decanter 4 , which will keep inside the moisture from the air. Therefore this air decanter will get rid of the water from the air system.
[0012] A governor valve 5 to control air pressure throughout the system will keep the pressure at 8 kg./cm 2 or 112 pound/square inches; another valve 6 will put the air input into different tanks avoiding its return; a rear brake tank 7 and a front brake tank 8 will store stocks of air in order to be used in the rear and front brake circuits, respectively; a storage tank 9 will store stocks of air in order to be used in the pneumatic suspension system; a tank for the handbrake 10 will store stocks of air, which can be manually or automatically used in case of emergency; an air-stop valve 11 will allow the air to enter in only one direction avoiding its return.
[0013] This system includes air chambers 12 which receive air pressure which will result in a mechanical motion and will put pressure on the camshafts. These devices run with a rubber diaphragm classified as pneumatic cylinders, which are supplied with, seals, O'rings, U-packings. The cylinders can be part of a dual circuit system used as parking or emergency brake as long as they are operated in the vehicle's traction system.
[0014] There is also a jettison valve 13 to reduce the time spent in the air release. A foot valve of dual circuit 14 will send air pressure to both circuits independently. This device is a safety measure in case the system fails to make sure the vehicle's brakes will always work. There is also a stop bulb comprising an electrical pneumatic valve. This will receive an air signal that will result in an electrical signal due to pressure 16 lower than 4 kg/cm 2 . Therefore, a warning light will be displayed on the instrument panel. There is a parking or emergency handbrake valve 17 used to apply the brakes system manually, temporarily or permanently in case of a pressure fall lower than 4 Kg./cm2. A manometer is also included 18 .
[0015] Flexible joints 19 will be made of rubber with a steel braid inside. There is also an external rubber of 22 mm in diameter covering the joint. The distance between the wires will be 1.5 mm. The female and male parts will be sealed by an aluminum gasket. The system will also include front air chambers 20 that will be in charge of not only receiving air pressure and turn it into a mechanical motion but also putting pressure on the camshaft. The cylinders can be part of a dual circuit system to be used as a parking or emergency brake when they do not run in the vehicle's traction system since they operate in front brakes.
[0016] This system is easy to understand once a clear definition of all the elements used in the present invention is provided. As it is previously mentioned, the users will hold down the pedal 14 so the air fills each of the rear and front chambers 12 and 20 . This procedure brakes the vehicle. In case of emergency, a lever 17 will fill the rear chambers with air 12 . This motion produces the exact pressure on the camshafts so the vehicle will quickly brake.
[0017] In FIG. 2 a dual circuit brake system is shown, which includes several elements of the system described in FIG. 1 : an air compressor 1 , an air decanter 2 , an air governor valve 3 , a protective and distributor valve comprising four circuits 4 , which puts the air input into the different tanks o as to prevent the loss of air, dual circuit foot valve 5 . The foot valve sends air pressure to both circuits separately because if one circuit fails, the vehicle will not loose its complete brake system. There is also a stop bulb 6 , an air stop valve 7 which will allow the air to enter in only one direction avoiding its return, a distributor and protective valve comprising two circuits 8 which will receive the air through the main tubing. Then the air is sent to two different circuits. At the same time it protects the circuits from a loss of pressure. There are front and rear air chambers 9 and 10 , a jettison valve 11 , a manometer 12 , a handbrake valve for the trailer that will brake the trailer manually by means of pulling out a handle 13 , a valve to be used as a parking or emergency brake 14 , a low pressure bulb 15 , a two way device which will connect the vehicle to the trailer in a safe and automatic way. There will be a permanent flow of air inside which will result in an “air signal” as well as a safety valve 17 with a 9 kg/cm pressure opening. In case of requiring a lower or higher level of pressure, the device will fit the right pressure. This valve will operate only when the system fails or the governor valve stops running. There will also be hand brake tanks 18 , a rear brake tank 19 , front brake tanks 20 , a faucet 21 placed in the low part of the tanks. The faucet is used to remove the water or oil remaining inside the tanks.
[0018] This system is easy to understand once a clear definition of all the elements or devices used in this invention is provided. The users will just hold down the pedal 5 so the air fills each of the rear and front chambers 9 and 10 . This procedure will brake the vehicle. In case of emergency, the vehicle will be braked manually by means of a lever 13 which will fill the rear chambers with air 9 . This motion produces the right pressure on the camshafts so the vehicle will quickly brake.
[0019] FIG. 3 shows a complex brake system of dual circuit which consists of front air chambers 1 ; a brake pedal with a dual circuit foot valve 2 which is operated mechanically. It turns the motion into an air opening. There is also a dual circuit foot valve 3 , which is also foot operated and as it consists of two circuits, it sends the air to both circuits separately. This is a safety measure in case the system fails so as to make sure the vehicle's brakes will always work.
[0020] A governor valve with a filter and connections to fill tires 4 will control the air pressure in the whole system. The proper pressure is 8 Kg./cm 2 112 pound/inches 2 ; the air is filtered when it gets into the brake system. There will also be an air pump used to fill tires, to release blast of air in gas filters etc.
[0021] A valve to stop the engine 5 will be operated by means of a lever near the foot on the cabin floor. This valve will pneumatically close a gate in the engine so that it can slow down the engine revolutions. There will also be a jettison valve to reduce the time of the air release 6 , a dual safety valve 7 with a 4 Kg./cm2 air opening in one circuit and 5 Kg./cm2 in the other; a control connection 8 comprising a screw thread and a pump to measure or release air pressure; front air brake tanks and trailers or wagons 9 ; a faucet to remove moister 10 , air chambers with blockers 12 ; a pressure regulator according to cargo (sensitive valves to cargo) 13 which regulates the vehicle's cargo considering the intensity of the brakes in the shaft by means of a detector, a relay valve to brake the trailer or wagon 14 . This valve will receive three signals: the first one corresponds to the foot valve or pedal, the second one corresponds to the trailer hand brake and the third one to the parking and emergency brake valves. These signals are transmitted and multiplied to the trailer.
[0022] A two way device in trailers and wagon hoses 15 will connect the vehicle or tractor to the wagon or trailer in a safe, automatic and quick manner. There will be a permanent flow of air inside which represents the “air signal”, a lever will avoid loss of air 16 by means of controlling the air pressure. There will also be a safety regulator valve to check whether the air goes to the trailer properly 17 . This valve will allow proper air pressure input in the trailer. There will be an air pressure in the tractor, sewer or harvester of 9 Kg./cm2. the air pressure to the trailer will be only limited to 6 Kg./cm2.
[0023] The air inside the tanks are used in the parking and emergency brakes 18 . It will be stored as reserve, and it can be used manually and automatically in emergency situations by means of lowering the pressure in the air system, a hand brake device 19 comprising a pneumatic and electrical valve that will receive an air signal which will result into an electrical signal. There are also a parking and emergency hand brake 20 which will apply the brake system to the rear circuit temporarily or permanently. This brake will also be applied automatically if there is a low of pressure lower than 4 Kg./cm2. A two way valve 21 will receive the air through the main tubing transferring it to the both circuits separately. This will additionally protect the circuits from a loss of pressure.
[0024] In this brake system ( FIG. 3 ), there are also a hand brake valve for trailers 22 to brake the vehicle manually by means of pulling out a lever. This action is totally pneumatic and electrical pneumatic. An air compressor 23 is also included together with an electrical pneumatic device of low pressure 24 which will turn a loss of pressure lower than 4 Kg./cm2 into an electrical signal. A warning light will be displayed on the instrument panel, an electrical pneumatic device used in the parking brake 27 comprising an electrical pneumatic valve. In case of a loss of pressure the valve will produce an electrical signal. A warning light will be displayed on the instrument panel to show that the parking or the emergency brake is activated.
[0025] Each of the air brakes systems as well as pneumatic suspension described may be applied to any tractor or pulled equipment regardless the vehicle trademark and origin. This system works parallel with the hydraulic and mechanic brake systems that tractors originally include. The original brake system may be modified to turn it completely pneumatic. Therefore, the pneumatic system is compatible to other systems assuring the system run properly by means of a clean, safe and non-polluting air system.
[0026] The pneumatic suspension system can modify the height of all the equipment according to the vehicle's needs. This system can also be fully automatic according to the land. | The present invention concerns a pneumatic system for an agro-industrial vehicle including an air compressor, a dual circuit foot valve connected to the air compressor, and at least two air storage tanks connected to said dual circuit foot valve. The operation of the dual circuit valve establishes an air pressure link from the storage tanks to a rear air chamber as well as to a front air chamber. Each storage tank fills the rear or front air chambers and the movement of the rear air chamber and the front air chamber activate a brake device. | 1 |
This invention was made with Government support under a contract awarded by the Government. The Government has certain rights in this invention.
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and method for improved thermal conductivity and mechanical support between structures in travelling-wave tubes and, additionally and in combination, for providing shock-resistance and vacuum exhaust in travelling-wave tubes.
In travelling-wave tubes a stream of electrons is caused to interact with a propagating electromagnetic wave in a manner which amplifies the electromagnetic energy. To achieve such interaction, the electromagnetic wave is propagated along a slow-wave structure, or circuit section. The circuit section is housed by a wall in a vacuum environment. A conventional circuit section may include a conductive helix wound about the path of the electron stream or a folded waveguide type of structure. The latter structure also may be known as a coupled cavity or interconnected-cell type. Regardless of its specific configuration, a waveguide is effectively wound back and forth across the path of the electrons. The slow-wave structure provides a path of propagation for the electromagnetic wave which is considerably longer than the axial length of the structure and, hence, the travelling wave may be made to effectively propagate at nearly the velocity of the electron stream. The interactions between the electrons in the stream and the travelling wave cause velocity modulations and bunching of electrons in the stream. The net result may then be a transfer of energy from the electron beam to the wave travelling along the slow-wave structure.
In the coupled-cavity type of slow-wave structure, a series of interaction cells, or cavities, are disposed adjacent to each other sequentially along the axis of the tube. The electron stream passes through each interaction cell, and electromagnetic coupling is provided between each cell and the electron stream. Each interaction cell is also coupled to an adjacent cell by means of a coupling hole at the end wall defining the cell. The travelling-wave energy traverses the length of the tube by entering each interaction cell from one side, crossing the electron stream, and then leaving the cell from the other side, thus travelling a sinuous or serpentine, extended path.
To function properly, such travelling-wave tubes must operate within an acceptable temperature range and, therefore, the heat generated in the circuit section must be removed. Thus, the circuit section must be supported in intimate thermal contact with the vacuum wall by some form of mechanical bond in order to conduct the heat from the circuit section to a heat sink thermally coupled to the vacuum wall.
Conventional thermomechanical bonds may be formed by brazing, heat shrinking, crimping, coining and clamping, as described in U.S. Pat. Nos. 3,268,761 (brazing or spot-welding), 3,540,119 (heat shrinking), 4,712,293 (crimping), 4,712,294 (coining) and 3,514,843 (clamping). A further U.S. Pat. No. 2,943,228 claims a simplified clamp lacking such means for joining parts as welds, brazes, or other metal flow processes. Notwithstanding, under conditions of high heat load, these bonding techniques may contribute to a potential decrease in performance of the travelling-wave tube, for example, by an adverse change in the circuit RF match, in the event that the structure of one or both of the joined elements deform by exertion of pressure from the bond, by stress resulting from changes in temperature, humidity and the environment, or by contamination from braze alloy and the like. Thus, it is desired that any such decreased performance be avoided.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a thermomechanical bond as a resiliently biased bond, specifically, as a helically shaped or wavy spring. By bonding the spring at its external surfaces to the vacuum wall and the circuit section, both an intimate mechanical and thermal contact and a vibration and shock resistant mounting for the circuit section is effected. In addition, the helical spring, in particular, can be used as a conduit for exhaust of gases from the travelling-wave tube during its fabrication.
Several advantages are derived from this arrangement. Any adverse effect on the circuit RF match is minimal. The circuit sections are protected from deformation and damage and, in addition, are protected from shock and vibration. Heat transfer is improved and the temperature of the circuit sections is lowered. The circuit sections can be symmetrically supported. Fabrication of the travelling-wave tube is facilitated, including the establishment of a vacuum therein. Compression of the circuit sections can be precisely controlled by judicious selection of the spring material and its configuration. Prevention of contamination can be better controlled.
Other aims and advantages, as well as a more complete understanding of the present invention, will appear from the following explanation of exemplary embodiments and the accompanying drawings thereof.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in partial cross-section of a travelling-wave tube incorporating a preferred embodiment of the present invention comprising a pair of helical springs thermally and mechanically supporting a circuit section within a vacuum wall of the travelling-wave tube;
FIG. 2 illustrates a method of using a mandrel for forming one of the helical springs of the embodiment of FIG. 1;
FIG. 3 is a cross-section of the spring and mandrel taken along line 3--3 of FIG. 2;
FIG. 4 is an enlarged cross-sectional view of the spring and mandrel depicted in FIGS. 2 and 3 taken along line 4--4 of FIG. 3;
FIG. 5 shows the helical spring wound on a wire or spindle of lesser diameter than that of the mandrel for reducing the diameter of the spring in preparation for its insertion within a groove in the circuit section;
FIG. 6 illustrates the insertion of the reduced diameter spring within the groove between the circuit section and the vacuum wall of the travelling-wave tube;
FIG. 7 depicts the helical spring inserted in the travelling-wave tube and secured at its ends to pole pieces supported on the vacuum wall;
FIG. 8 shows a segment of the circuit section having diametrically opposed grooves therein;
FIG. 9 is an enlarged cross-sectional view of the circuit section segment of FIG. 7 taken along line 9--9 thereof;
FIG. 10 is a modification of the spring configured as a wavy spring; and
FIG. 11 is a comparison of temperature versus input power data derived from tests on circuit sections in which a helical spring was and was not used to experimentally verify that the present invention provides improved heat transfer and a lower circuit temperature.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a travelling-wave tube 20 includes a slow-wave structure 21 within a magnetic focusing assembly 22, and housings 24 and 26 at opposite ends thereof for respective housing of an electron gun and a collector electrode (not shown). Input and output waveguides 28 and 30 are coupled to the respective ends of slow-wave structure 21.
As shown also in FIGS. 6-8, slow-wave structure 21 has an outer vacuum vacuum wall member 32, and a plurality of serially positioned cavity-defining members 34 (see FIG. 8, in particular) coaxially and sequentially housed within vacuum wall member 32. Focusing assembly 22 includes a series of outwardly extending pole pieces 36 secured to vacuum wall 32 by spacers 38. A series of magnets 39 are disposed between respective pairs of adjacent pole pieces 36 radially outwardly of respective spacers 38.
As shown in FIG. 8, each cavity-defining member 34 has a drift tube or ferrule 40 provided with a tubular opening 42 extending along the axis of slow-wave structure 21. Cavity-defining member 34 further includes an annularly shaped outer portion 44 to which drift tube 40 is secured by a web 46 and which is bounded by a periphery 48. As best illustrated in FIG.9, periphery 48 is spaced from inner surface 33 of vacuum wall member 32 toprovide an annular space 50 therebetween having a gap 51 whose radial dimension may be between 5 and 7 mils. A pair of diametrically opposed grooves 52 of depth 53 are formed in annular outer portion 44. A pair of axially extending helical springs 54, which define interiors 55 (shown in FIG. 9), reside in respective grooves 52. As discussed below, interiors 55are used to advantage in the assembly of travelling-wave tube 20. Each spring 54 has a normal diameter which is greater than distance 56 which isthe sum of the cross-sectional extent of groove 52 and gap 51 so that spring 54 is compressed and thus forms a resilient, firm thermomechanical joint between each cavity-defining member 34 and vacuum wall member 32. Ifdesired, springs 54 may be bonded at their external peripheries to grooves 52 and surface 33.
Springs 54 may take any desired shape, a helix being preferred; however, they may be configured as wavy springs 58, as illustrated in FIG. 10. Also, while grooves 52 are shown as paired in diametrical opposition in cavity-defining member 34, any further number of grooves may be used, and this further number need not be evenly spaced from one another about periphery 48, so long as springs 54 or 58 provide the desired thermomechanical joint between surface 33 of vacuum wall 32 and periphery 48 of cavity-defining member 34.
Fabrication of the springs, and assembly of the thermomechanical joint may be effected in any suitable manner. The following technique has been foundto be effective, and is based upon successfully made, actual joints in a radially-dimensioned gap 51 of 5-7 mils. As illustrated in FIGS. 2-5, a wire 60 of suitable material, such as of molybdenum, tungsten, rhenium, dispersion hardened copper, and an alloy of tungsten and rhenium is wound on a mandrel 62 as shown in FIGS. 2 and 3. The diameter of spring 54 on mandrel 62 is designated by indicium 63 (see FIG. 2). For travelling-wave tube use, the preferred wire is a doped, non-sag grade of molybdenum, which does not recrystallize and become brittle as easily as the non-dopedmaterial. The resultant wound spring is made longer than that of groove 52 into which it is to be placed, for reasons which will become evident. While the spring is still attached to mandrel 62, a plate 64 (see FIG. 4),comprising gold over a strike of nickel, is formed on the exterior surfacesof the spring; it is not necessary that the plate exist on the interior of the spring.
As depicted in FIG. 5, spring 54 is then removed from the mandrel and slipped over a spindle 66 having a lesser diameter than that of the mandrel. Like spring 54, spindle 66 has a length which exceeds that of grooves 54. Spring 54 is then secured at one end 68 to spindle 66 by a spot weld 70, and tightly wound about spindle 66 to decrease the spring's diameter from its former larger diameter 63 to a value, denoted by indicium 67, which is less than the combined cross-sectional extent of groove 52 and gap 50 (denoted by indicium 56 shown in FIG. 9). The other end 74 of spring 54 is clamped to spindle 66 by a collet 72.
Each spring 54, as secured to its spindle 66, is then inserted into the space formed by groove 52 and gap 51 as shown in FIG. 6 and indicated by arrows 76, until both wire ends 68 and 74 extend beyond the respective ends of the assembly of cavity-defining members 34. If desired, the spring-spindle assembly may be turned, and therefore threaded, as an aid to its insertion. With the ends extending beyond the respective ends of the assembly of members 34, spindle 66 is rotated and twisted in the direction opposite from the threading direction to permit spring 54 to expand into engagement with the walls of groove 52 and vacuum wall member 32. Weld joint 70 is broken and collet 72 is removed to release spring 54 from spindle 66, which is then removed, thus leaving spring 54 inside its groove 52 with a mechanical interference contact with vacuum wall member 32 on one side and all cavity-defining members 34 on the other.
The spring length is then cut to size to the length of the assembly of cavity-defining members 34, and the cut ends of the springs are secured tothe respective end pole pieces 36 by spot brazing using a shim, e.g., of palladium-cobalt alloy.
The thus-fabricated and enclosed vacuum assembly is heated and otherwise processed in a conventional manner to exhaust its interior to a vacuum, aswell as to provide a metallurgical diffusion of gold into the surfaces of vacuum wall member 32 and cavity-defining members 34 in contact with springs 54. As an aid in exhausting the assembly, interiors 55 of springs 54 act as conduits for removal of gases.
The dimensions of the components used in a typical assembly to form a thermomechanical joint for radially-dimensioned gap 51 of 5-7 mils were asfollows. Wire 60 comprised a 0.006"±0.0001" diameter doped, non-sag molybdenum wire. Mandrel 62 was formed of tungsten having a diameter of 0.0190"+0.0000" and -0.0002". Wire 60 was precision wound about mandrel 62to a constant pitch of 0.0169"±0.0002". Spindle 66 comprised a 0.015" diameter nickel wire.
As shown in FIG. 11, curves 80 and 82 represent test data taken on circuit sections respectively without any spring support and with the support of helical spring 54 of the present invention. The comparison of temperature versus input power data derived from the tests on circuit sections experimentally verify that the present invention provides improved heat transfer and the lowering of the circuit temperature.
Although the invention has been described with respect to particular embodiments thereof, it should be realized that various changes and modifications may be made therein without departing from the spirit and scope of the invention. | In a travelling-wave tube (20), a cylindrically-shaped slow-wave circuit cavity-defining member (34) is supported by and is thermomechanically bonded to a tubularly-configured vacuum wall member (32). The bonded joint comprises a pair of arcuate grooves (52) extending lengthwise of the slow-wave circuit and positioned diametrically opposite one another about the axis of the tube. A helical or wavy spring (54, 58) lies in each groove and is resiliently biased in intimate mechanical and thermal contact between the groove and the vacuum wall. The helical spring, in particular, can be used as a conduit for exhaust of gases from the travelling-wave tube during its fabrication. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 12/618,433, entitled “Anonymous Shopping Transactions On A Network Through Information Broker Services,” filed Nov. 13, 2009, which is a continuation of U.S. patent application Ser. No. 09/821,040, entitled “Anonymous Shopping Transactions On A Network Through Information Broker Services,” filed Mar. 30, 2001, which issued as U.S. Pat. No. 7,640,187 on Dec. 29, 2009, the contents of which are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] This invention relates to a system and method for carrying out anonymous shopping and other on-line transactions over a network through the use of information broker services.
BACKGROUND OF THE INVENTION
[0003] The rise in the popularity of interconnected, processor-based networks, such as the Internet, has increased the practice of on-line shopping. The increase of on-line shopping has made it possible for consumers to purchase goods and services with ease. Often, consumers are able to purchase items from the convenience of their own home at any hour of the day.
[0004] However, in order to complete an on-line transaction, users are typically required to submit personal, confidential, or otherwise private information over the network to the on-line merchant. Once submitted, the information may be intercepted or otherwise accessed by unintended or unauthorized persons. Obviously, this is an undesirable result. Thus, it is desirable to carry out on-line transactions without needlessly endangering private information.
[0005] For example, buyers are typically required to submit a credit card number to the on-line merchant in order to pay for the desired goods or services. However, submitting a credit card number over the network opens the possibility that the credit card number will fall into the wrong hands and unauthorized charges may result.
[0006] Buyers are also asked to provide their legal names (usually as it appears on the credit card account). For numerous reasons, buyers may not want to provide their real name over the network. For example, for safety reasons, women living alone may not want to provide their real names. Similarly, buyers may not want to provide their home address when purchasing items on-line.
[0007] These and other drawbacks exist.
SUMMARY OF THE INVENTION
[0008] One advantage of the invention is that it overcomes these and other drawbacks in existing devices.
[0009] Another advantage is that the invention provides a system and method for enabling consumers to shop on-line without having to reveal personal information.
[0010] Another advantage is that the invention provides a system and method for using an information broker service to disguise a user's personal information and enable the user to accomplish on-line shopping in an anonymous fashion.
[0011] According to one aspect of the invention, there is provided a method for enabling a user to transact an anonymous on-line transaction, wherein a form of on-line payment is requested at a transaction interface. The method may include providing an anonymous user interface that enables a user to initiate an on-line payment, accessing a first profile comprising user data when the user activates the form of on-line payment, generating a second profile linked to the first profile wherein, the second profile comprises anonymous data, and communicating the anonymous data from the second profile to the transaction interface to enable completion of the transaction.
[0012] According to another aspect of the invention, there is provided a system for enabling a user to transact an anonymous on-line transaction, wherein a form of on-line payment is requested at a transaction interface. The system may include an anonymous user interface that enables a user to initiate an on-line payment, a profile access initiator that accesses a first profile comprising user data when the user activates the form of on-line payment, a profile generator that generates a second profile linked to the first profile wherein, the second profile comprises anonymous data, and an anonymous data communicator that communicates the anonymous data from the second profile to the transaction interface to enable completion of the transaction.
[0013] Other advantages and features of the invention will be apparent to those of skill in the art from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic of the overall system according to one embodiment of the invention.
[0015] FIG. 2 is a schematic of an anonymous shopping interface according to one embodiment of the invention.
[0016] FIG. 3 is a schematic flow diagram illustrating an anonymous shopping method according to one embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Operation of the invention may be described with reference to the following example embodiments. One embodiment applies to, among other things, the situation when a user wants to buy products on the Internet without supplying their credit card number. In this situation, a credit card issuer (e.g., a bank, credit union, or other credit card issuing entity) acts as an information broker and supplies a single-use credit card number for the user to use while conducting an on-line transaction on the Internet site. The Internet site receives and processes the single-use number the same as any other credit card number. The credit card issuer treats the card as a transaction card (i.e., single-use) as long as certain security criteria (explained below) are met.
[0018] For example, the above embodiment may be implemented as follows. A user's Internet browser interface may be adapted to include an anonymous shopper interface. The anonymous shopper interface may contain a representation (e.g., graphic image) of a credit card. When the user comes to the purchase point, or other request for a form of on-line payment, during his/her on-line shopping transaction he/she may activate the anonymous shopper interface credit card to complete the purchase. In some embodiments, activating the anonymous shopper card may activate a form fill-in procedure that reads the amount of the transaction (i.e., the amount of the purchase and any shipping, tax or other additional costs) and uses that amount to complete other transaction procedures as described below.
[0019] Activation of a form of on-line payment via the anonymous shopping interface may cause a profile access module to initiate access to a stored profile that a user may store containing credit card information corresponding to the credit card account for which the user wants the on-line transaction charges to ultimately be debited. For example, the stored profile may include the user's name, address, credit card account number, account expiration date, and any other information helpful for accomplishing on-line shopping. The profile may be stored at any suitable location. For example, the profile may be stored with the anonymous shopper interface provider, the credit card issuer, the user (e.g., in the user's hard drive), or any other suitable location. Regardless of storage location, upon activation via the anonymous shopper interface, the profile is retrieved for further use in the on-line transaction as described below.
[0020] The amount of the transaction and the stored profile information are then communicated through a secured line to the credit card issuer or other information broker. The secured line prevents unauthorized access to the user's private information.
[0021] The invention provides a transaction number generator software module for use by the credit card issuer or other information broker processing center. The number generator module generates a single use anonymous transaction number, associated with the user's credit card account, which functions as a “normal” credit card number. The anonymous transaction number is returned over the secured line and filled-in as card credit card number to complete the on-line shopping transaction.
[0022] Thus, instead of exposing the user's credit card number, the credit card issuer issues an anonymous per transaction credit card account with a purchase limit based on the transaction amount and an expiration date based on the month/year that the transaction takes place.
[0023] This means that the credit card issuer can issue at least one trillion unique credit cards per month. If that limit is hit, some of the numbers in the first four numbers of the user's credit card may be used to create a new limit of one trillion transactions per week.
[0024] The user's actual credit card number is never sent over the Internet. The only transmission of the actual credit card number occurs between the anonymous shopper interface and the credit card issuer over a secure private connection. In this manner, the user removes much of the risk of unauthorized use of their credit card. The credit card issuer also reduces their risk of someone stealing the credit card.
[0025] Another aspect of the invention applies to the situation when a user wants to conduct a transaction on the Internet without giving out their real name. Currently, users must use their real, or legal, name when supplying their payment and/or shipping information. One embodiment of the invention allows a user to associate an alias or fake name with the selected form of on-line payment (e.g., a single-use credit card).
[0026] The alias may be created in any suitable fashion. For example, the alias may be created by the user and stored in a profile. Alternatively, the user may be prompted to submit an alias as part of the request for a single-use transaction number. In any event, the alias name is transmitted to the on-line shopping site (e.g., through auto-form fill) as the name of the credit card account holder. In this manner, the site completes the on-line transaction using the alias name and the user never transmits his/her real name over the Internet.
[0027] Another aspect of the invention applies to situations when the customer wants to conduct a transaction anonymously without having to provide a home shipping address. In such a scenario, the invention enables a delivery service (e.g., U.S. Postal Service, UPS, Federal Express, etc.) to act as an information broker for the shipping address.
[0028] For example, the above embodiment may be implemented as follows. An anonymous shopper interface may include a representation of a delivery service logo or other identifier. When presented a delivery address request form, the user may select the desired delivery service logo in the anonymous shopper interface. Selecting the delivery service logo sends the delivery address request, along with a user identifier, to the anonymous shopper interface provider.
[0029] A user identifier may comprise any identifier that will uniquely correspond to the user. For example, a user identifier may comprise a uniform resource locator (URL), a domain name, an email address, a globally unique identifier (GUID), or other unique identifier.
[0030] The anonymous shopper interface provider verifies the user identity (e.g., using a password or other authentication scheme) and retrieves the user's address, billing and other information that the delivery service needs to complete the transaction.
[0031] Communication between the anonymous shopper interface and the delivery service is conducted over a private-secure connection. Upon receipt of the request, the delivery service generates an anonymous address. For example, the anonymous address may comprise the address of a delivery service hub station with a special routing code embedded in the address.
[0032] The anonymous shopper interface inserts the anonymous address into the on-line shopping site's shipping address form (e.g., through auto-form fill). The on-line shopping site sends the user's items to the anonymous address in the same manner as any other address. When the user's package reaches the delivery service hub station address, the delivery service recognizes the anonymous address and routes delivery to the user's real address. In this manner, the user can shop on-line without fear of revealing private information such as a home address.
[0033] The above embodiments are but a few examples of the invention. Other applications and embodiments will be apparent to those of skill in the art upon reading the following detailed description of the figures.
[0034] FIG. 1 shows a schematic of the overall system 100 according to an embodiment of the invention. As shown, the various parties involved in on-line shopping interact through the medium provided by the Internet 102 . Those parties may include users 104 , on-line shopping sites 106 , anonymous shopping interface providers 108 , and information brokers 110 .
[0035] As described above, users 104 includes persons interested in carrying out an on-line shopping transaction. Users 104 may comprise private individuals, businesses, government entities, or other organizations.
[0036] On-line shopping sites 106 may include any Internet site that enables a user 104 to order, purchase, lease, or otherwise obtain, goods or services over the Internet 102 .
[0037] Anonymous shopping interface provider 108 represents the entity or entities that provide the anonymous shopping interface 200 described herein. For example, anonymous shopping interface provider 108 may comprise software providers, Internet service providers, or a combination of these and other computer related service providers. As described above, the anonymous shopping interface provider 108 provides the user 104 with an anonymous shopping interface 200 that enables the user to carry out an anonymous on-line shopping transaction.
[0038] Information broker 110 represents the entity or entities that provide the information that enables the user to complete an anonymous on-line shopping transaction. For example, for embodiments where a user wishes to shop with an anonymous credit card account, information broker 110 may comprise a bank, credit union, or other financial institution that issues credit card accounts. Similarly, for embodiments where a user wishes to shop with an anonymous address, information broker 110 may comprise a post office, package delivery service, or other delivery service. Of course, for any given transaction information broker 110 may comprise more than one type of entity (e.g., a bank and a delivery service).
[0039] As described herein, anonymous shopping interface provider 108 and information broker 110 communicate over a secure communication link 112 . Secure communication link 112 may comprise any suitable communication link having appropriate security guarantees. For example, secure communication link 112 may comprise a credit card authorization network, a secure satellite communication link, a secure telephone communication link, a secure computer network connection, or other secure communication link.
[0040] As described above, some embodiments of the invention may comprise a user profile that is stored at a conveniently accessible region. For example, profiles may be stored at storage device 114 . Storage device 114 may comprise any suitable storage device capable of storing user profile information. For example, storage device may comprise a database storage system, a hard drive storage system, or the like.
[0041] As indicated by the dashed lines in FIG. 1 , communication between storage device 114 and the rest of system 100 may be accomplished in a number of different fashions. For example, storage device 114 may comprise a hard drive storage system in communication with user 104 , a database storage device in communication with anonymous shopping interface provider 108 , or some other storage scheme may be implemented.
[0042] FIG. 2 is a schematic representation of an anonymous shopper interface 200 according to one embodiment of the invention. As shown, a user may browse the Internet using a suitable browser interface 202 . For example, browser interface 202 may comprise a browser such as Netscape Navigator™, Microsoft Internet Explorer™, America On-Line™ browser, or another suitable interface.
[0043] Browser 202 operates in a known manner and may comprise a toolbar 204 that allows a user to perform various browsing tasks (e.g., forward, back, print, refresh, home, etc.). As shown, browser 202 enables the user to visit Internet sites and view the various images 206 , links 208 , buttons 209 , and other site features.
[0044] One embodiment of the anonymous shopping interface 200 provides an anonymous shopping toolbar 210 that includes the anonymous shopping tools. FIG. 2 shows one embodiment of an anonymous shopping toolbar 210 located as a bar at the bottom of browser 202 . Of course, other configurations are possible. For example, anonymous shopping toolbar 210 may be located at the top or side of the browser 202 . Additionally, the anonymous shopping toolbar 210 may comprise a separate window that overlays the browser 202 and is positionable and sizable according to user preference. Other embodiments of the anonymous shopping toolbar may comprise a separate icon or button on browser toolbar 204 that may activate a menu of anonymous shopping tools. Other configurations are possible.
[0045] Anonymous shopping toolbar 210 may comprise various tools to enable the anonymous shopping activities described herein. For example, tools may be provided to enable anonymous credit card accounts (e.g., credit tool 212 ), alias names (e.g., name tool 214 ) and anonymous delivery (e.g., delivery tool 216 ). Other tools may be provided as indicated by other tool 218 .
[0046] The tools may take any acceptable form on the anonymous shopping toolbar 210 . For example, tools may comprise buttons that may be activated by clicking with a pointer (e.g., a mouse cursor), pull-down menus, radio buttons, links, or other user selection devices.
[0047] FIG. 3 is a schematic flow diagram illustrating a method of anonymous shopping according to one embodiment of the invention. As shown, a user may activate an anonymous shopping tool (e.g., credit tool 212 ) at step 300 . Activation of a tool may be accomplished by user selection of the tool (e.g., by clicking on or otherwise selecting the tool).
[0048] Selection of a tool may initiate access to the user's profile as indicated at step 310 . As described herein, the user's profile may be stored at any convenient location and preferably includes user information that assists in completing an on-line shopping transaction.
[0049] At step 312 , transaction related information is submitted to an information broker (e.g., information broker 110 ). Transaction related information may comprise purchase price, on-line merchant information (e.g., name, address, etc.), user profile information, and other transaction related information.
[0050] At step 314 the information broker 110 generates the anonymous information requested by the user to accomplish the transaction. For example, if information broker 110 is a credit card company, step 314 may comprise generating a single use credit card number for the user to submit to the on-line merchant. Other examples of anonymous information are described above.
[0051] At step 316 the anonymous information is returned so that it may be submitted to the on-line merchant. As described herein, in some embodiments the anonymous information may be returned to the user for the user to submit to the on-line merchant. In other embodiments, the anonymous information may be submitted to the on-line merchant directly. Other schemes are possible.
[0052] In some embodiments, the anonymous information may be submitted as part of a form fill-in procedure. This is indicated in FIG. 3 as steps 318 A and 318 B. The form fill-in steps may be accomplished at any convenient time in the process. For example, the form fill-in 318 A may be accomplished upon activation (e.g., at 318 A), after the information is returned from the information broker 110 (e.g., at step 318 B), at a combination of the two times (e.g., some information filled at 318 A and some at 318 B) or at some other convenient time.
[0053] At step 320 the on-line shopping transaction is completed. For example, the information necessary to complete the on-line transaction, including the anonymous information, is submitted to the merchant.
[0054] Other embodiments and uses of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The specification and examples should be considered exemplary only. The scope of the invention is only limited by the claims appended hereto. | A system and method for enabling a user to transact an anonymous on-line transaction, wherein a form of on-line payment is requested at a transaction interface is disclosed. The method may include providing an anonymous user interface that enables a user to initiate an on-line payment, accessing a first profile comprising user data when the user activates the form of on-line payment, generating a second profile linked to the first profile, wherein the second profile comprises anonymous data, and communicating the anonymous data from the second profile to the transaction interface to enable completion of the transaction. | 6 |
TECHNICAL FIELD
This invention relates in general to the field of ultrasonic welding, and in particular to ultrasonically welding thin-walled components.
The demand for small, light-weight consumer products has increased substantially in recent years. This demand for smaller, lighter-weight products has forced manufacturers of these products to employ ultrathin ultralight products in, for example, the plastic housing of the products. These ultrathin plastic housings often have thicknesses on the order of between 0.20 and 0.50 mm.
These thin plastic housings are low weight, and rely upon the structure of the item being housed for structural stability. However, they pose several challenges in the manufacturing arena, and particularly, in joining two or more such plastic pieces. Typically, ultrathin plastic parts must be bonded together with adhesives because standard ultrasonic welding techniques are not feasible.
Traditionally, thick plastic parts have been joined ultrasonically by aligning the parts, and initiating the weld along an energy director formed in one of the parts. Manufacturers have typically strengthened the ultrasonic weld between plastic parts by either increasing the weld depth, or increasing the size of the energy director, thus providing a larger weld area. However, adopting this approach with ultrathin plastic components results in numerous problems. For example, increased weld depth and/or energy director size also increases the likelihood of burning through one or more of the plastic parts, thus rendering the parts unusable. Deep welds also cause "flash" or seepage of the weld from between the welded components. Welds which completely melt one or both of the parts degrade the plastic, causing concentrated stresses at the weld joint.
Another problem associated with ultrasonically joining plastic parts arises from the tendency of the plastic parts to become mis-aligned during the welding process. The result is misformed parts which are at least cosmetically unacceptable, and at worst lacking in structural integrity.
Accordingly, there exists a need for a method of ultrasonically welding parts, particularly ultrathin plastic parts, which provides for enhanced weld strength, and improved part alignment.
SUMMARY OF THE INVENTION
Briefly, according to the invention, there is provided a method for ultrasonically joining at least a first and a second piece of plastic material via ultrasonic welding. The method comprises the steps of providing a plurality of energy directors around the peripheral edge of a bonding surface of said first plastic piece. The energy directors may be, for example, two or more sets of elongated, raised ridges extending from the bonding surface. Alternatively, the energy directors may be a plurality of raised, discrete cones extending from the bonding surface. The second piece to be joined may include a grooved flange around the peripheral edge. The groove in the flange is adapted to seat into the energy directors. Thereafter, the first and second pieces are brought into contact with one another so that said groove is seated in said plurality of energy directors. Pressure is applied to said plastic pieces to hold them in seated relationship. Finally ultrasonic welding energy is applied to said parts so that the energy directors melt, engaging the groove.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a plastic housing to be joined by a method in accordance with the invention;
FIG. 2 is a top plan view of the bonding surface of a first piece of a housing to be joined by a method in accordance with the invention;
FIG. 3 is a top plan view of the bonding surface of an alternative first piece of a housing to be joined by a method in accordance with the invention; and
FIG. 4 is a side view of a housing, taken along line 4--4 of FIG. 1,
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. 1, there is illustrated therein an exploded perspective view of a plastic housing 10 to be joined by a method in accordance with the invention. The housing 10 comprises a housing base 12 and a housing cover 14. The housing 10 illustrated in FIG. 1 is adapted to house a battery cell 16 (in phantom) for use in, for example, a portable telephone. However, it is to be understood that the invention is not so limited, and that the invention may be advantageously employed in joining any two plastic members, for any application. The housing base 12 and the cover 14 are typically fabricated of a thermoplastic material, such as, but not limited to Polycarbonate. The thickness of the thermoplastic material is typically between 0.20 and 0.50 mm. Accordingly, deep welds are not possible, as they will burn through the housing base 12, the cover 14, or both.
The housing cover 14 includes flanges 13, 15 extending from the edges thereof. Protruding from one side of the flanges 13, 15 is a groove. The groove is adapted to seat into energy directors (described below) so as to allow for better weld quality, and to assure proper alignment of the housing cover 14, and the housing base 12.
The housing base 12 may have a bonding surface 18 adapted to engage, for example, the item to be housed. The bonding surface 18 also provides a base for ultrasonically welding the housing cover 12.
Disposed around the peripheral edge of the housing base 12 is a plurality of energy directors 20 and 22. As illustrated in FIG. 1, the energy directors 20, 22 comprise two sets of elongated, raised ridges. However, as will be discussed in greater detail below with respect to FIG. 3, the energy directors may be a plurality of discrete, raised cones.
Referring now to FIG. 2, there is illustrated therein a top plan view of the housing base 12, having the energy directors configured as a plurality of elongated, raised ridges extending from the bonding surface 18. In this embodiment, the energy directors comprise three sets of elongated, raised ridges 20, 22, 24, extending from the bonding surface 18 of the housing base 12. The three sets of elongated raised ridges 20, 22, 24 are disposed around the peripheral edge of the bonding surface 18, although they may be disposed anywhere on the bonding surface. The periphery has been chosen so as to accommodate the battery pack illustrated in phantom in FIG. 1.
The raised ridges are typically formed integrally with the formation of the housing base 12, and hence are formed of a similar thermoplastic material. The raised ridges may be continuous, as illustrated in FIG. 2, or alternatively may be broken, or non-continuous so as to accommodate the item to be housed in the housing 10. The ridges may extend from the bonding surface a distance so as to make calculated interference between the first and second pieces, and usually extend between 0.20 and 0.70 mm. Further, each ridge may extend a different distance so as to strengthen the weld, while further reducing flash. The ridges may be shaped as a generally rectangular member, with a pointed termination on the end extending from the bonding surface 18. Alternatively, the ridges may be of other shapes, such as, but not limited to triangular or semicircular.
Referring now to FIG. 3, there is illustrated therein an alternative embodiment of the invention, wherein the energy directors are configured as a plurality of discrete raised cones. The cones are arranged in groups 30, 32, 34, 36, 38, 40 around the periphery of the bonding/surface 18. While FIG. 3 illustrates six groups of cones, each group consisting of 11 cones, it is to be understood that the invention is not so limited. Rather, any number of groups of cones, having any number of cones therewithin, arranged in any configuration is contemplated by the invention. The cones may extend from the bonding surface a distance so as to make some calculated interference, and usually of a distance of between 0.20 and 0.70 mm.
Referring now to FIG. 4, there is illustrated therein a cross-sectional view taken along line 4--4 of FIG. 1, illustrating the housing base 12, and the housing cover 14. The energy directors are configured as two sets of elongated ridges 20, 22 extending from the bonding surface 18. The ridges are of differing lengths (i.e., ridge 22 extends further from bonding surface 18 than does ridge 20) so as to improve the quality of the weld, while reducing flash. Disposed between the housing cover 14, and the housing base 12 is the item to be housed. The housing cover 14 includes flanges 13, 15 extending from edges thereof. Formed in each flange is a groove 42, 44 which protrudes downwardly from the flange, and toward the housing base 12. The grooves 42, 44 are adapted to seat between the ridges 20, 22 so as to prevent mis-alignment between the housing base 12, and the housing cover 14.
The joining process is completed by first urging housing cover 14 against housing base 12, as by the application of force to cover 14 in the direction of arrow B. Grooves 42 and 44 seat between the ridges 20 22, thus properly aligning the cover and base. Ultrasonic welding is accomplished by the application of welding energy via a welding horn 50 to the flanges 42 and 44. The thermoplastic material is melted achieving the weld.
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. | A process for joining at least two ultrathin plastic pieces by an ultrasonic welding method is disclosed. The process includes providing a plurality of energy directors for enhancing weld strength, and reducing unacceptable welds. The process also includes providing a groove in a flanged attachment member to assist in properly orienting the pieces to be joined. | 1 |
FIELD OF THE INVENTION
The present invention relates to pipe-driving apparatus for driving a succession of pipe sections end-to-end to form a pipe string.
BACKGROUND OF THE INVENTION
Pipe-driving apparatus is known in which an open access trench accommodates a pressing station for thrusting individual pre-fabricated pipe sections end-to-end to extend the pipe string. At the forward end of the pipe string material is excavated with a boring head. Normally the pipe section would have a small diameter such as not more than 1200 mm and generally below 800 mm which makes access difficult. It is known from AT-PS 35 27 74 to remove material from the forward end zone with a container which is movable between a filling position in the forward end zone and a discharge position at a rear end zone in the access trench. The container supports the boring head as well as an associated conveyor worm which extends inside the container. A drive unit for the boring head and the worm is mounted at the rear of the container. This makes the container rather bulky and it is difficult to hold the container in its working position. DE-PS 2 845 316 describes a modified arrangement where the boring head can be separated from the container when the latter is to be removed for unloading. However, if it is desired to repair or replace the boring head this is a difficult operation with a small diameter pipe string.
A general object of the present invention is to provide an improved form of pipe-driving apparatus.
SUMMARY OF THE INVENTION
Pipe-driving apparatus constructed in accordance with the invention comprises a pressing station in an access zone for thrusting a succession of pipe sections end-to-end to form a pipe string, a working pipe section at the front end of the pipe string defining a working zone, cutting means and a conveyor worm at the working zone for detaching material from a working face and for conveying such material away from the face, a displaceable container operably associated with the cutting means and the conveyor worm to receive said material, the container being movable between the working and access zones to transfer the material, a drive unit for driving the cutting means and the conveyor worm, the drive unit being supported by the container and bracing means which selectively co-operates with the working pipe section to brace the container and hold the container in position whilst it is filled with material.
The bracing means can be in the form of piston and cylinder units orientated predominantly axially of the pipe string which can be swivelled in and out radially of the string to adopt inoperative and operative positions. A transverse piston and cylinder unit can effect the adjustment of the bracing units. In the operative position the bracing units can locate with stop means on the inside of the working pipe section. This section then forms an abutment for the forces of the bracing units when these urge the container forwardly.
Conveniently, the working pipe section, which is best made of a stout steel structure also mounts a cutting shoe which effectively terminates the pipe string. The shoe preferably has some angular mobility on the working pipe section. The shoe may have a shoulder or flange against which projections or the like on the container can be thrust with the bracing units. This enables the bracing units to control the position of the shoe and axial adjustment means or other measures can be adopted to permit the shoe to be steered to control any deviation in the direction the pipe string is following. The container can be reliably held in position by the bracing units whilst it is filled with spoil detached by the boring head and conveyed by the worm. Reactive forces can be transferred to the pipe string via the working pipe section. When it is desired to withdraw the container for unloading the bracing units can adopt the stored inoperative position.
Preferably, a selective coupling serves to connect the boring head to a drive shaft extending through the container. A spiral flight on the drive shaft then constitutes the conveyor worm at least in part. The selective coupling permits the container to be withdrawn without taking the boring head with it. Another characteristic of the invention adapts the boring head to have a variable effective diameter larger or smaller than the internal diameter of the pipe string. In this way if it is desired to remove the boring head it can be collapsed and locked to the shaft to move with the container. Otherwise the boring head can remain in place in its operative condition while the container is removed and unloaded. Since it is not possible to gain direct access to the boring head via the pipe string provision can be made to fit different tools to the drive shaft to interengage with components of the boring head to perform different operations. Thus, it is possible to rotatably connect the boring head to the drive shaft while allowing axially separation or to axially lock the boring head and the drive shaft or to adjust the operating state of the boring head between its fully expanded and fully collapsed states.
A further preferred feature of the invention is to provide means for adjusting the conveyor worm or spiral flight relative to the container. This means which can take the form of a piston and cylinder unit mounted inside the drive shaft, permits the worm to compress material in the container or to extend the boring head further forwards.
The worm can be composed of a spiral flight section on the drive shaft running substantially the entire length of the container and a short flight section between the boring head and an open end of the container. The selective coupling then operates between these respective flight sections.
Pipe-driving apparatus constructed in accordance with the invention can be adapted more satisfactorily to the prevailing conditions and time consuming and cumbersome tasks can be minimized to increase the efficiency of the operation.
The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings, wherein:
FIG. 1 is a diagrammatic sectional side view of the apparatus constructed in accordance with the invention;
FIG. 2 is a diagrammatic sectional side view of a forward region of the apparatus the view being taken on a somewhat larger scale to FIG. 1;
FIG. 3 is a diagrammatic sectional plan view of the forward region of the apparatus depicted in FIG. 2;
FIG. 4 is a cross-section taken along the line IV--IV of FIG. 2;
FIG. 5 is a cross-section taken along the line V--V of FIG. 2;
FIG. 6 is a view corresponding to FIG. 2 but showing the forward region of a modified form of the apparatus; and
FIG. 7 is a diagrammatic sectional plan view of the boring head and coupling of the apparatus depicted in FIG. 6.
DESCRIPTION OF PREFERRED EMBODIMENTS
As shown in FIGS. 1 to 5, pipe-driving apparatus serves to drive a pipe string 6 composed of a succession of individual pipe sections end-to-end in the driving direction of arrow 1. The pipe sections, usually prefabricated from concrete, are introduced into an open access trench 2 in which there is a pressing station 3 equipped with hydraulic rams 4 which act on a thrust ring 5. The fresh pipe section is aligned at the rear of the last pipe section in the pipe string 6 composed of the previously installed pipe sections and the entire pipe string 6 is thrust forwards in the direction of arrow 1 with the thrust ring 5 and rams 4. If the pipe string 6 is of considerable length intermediate press stations can be adopted in known manner.
As can best be seen in FIG. 2, at the front end zone of the pipe string 6 there is a special working pipe section 7 conveniently made from steel on which there is a cutting device such as a shoe 9 with a cutter 10. The rear portion 11 of the shoe 9 engages over an axial region of the pipe section 7 with a certain clearance to provide some angular mobility between the pipe section 7 and the shoe 9 and thereby permit directional control.
Spoil in the form of soil or other debris is detached from a working face 8 in front of the cutter 10 with a boring head 13 such as an auger. The detached spoil is removed with the aid of a displaceable container 14 and a conveyor worm 15 linked to the boring head 13 installed in the pipe section 7. The container 14 is of rigid steel construction, conveniently cylindrical, open towards the working face 8 and closed at its rear end. The container 14 supports the worm 15 and the head 13 for rotation and is shown in FIGS. 2 and 3, in its working position being filled with spoil as the head 13 and the worm 15 working together to transfer the spoil from the face 8 rearwardly into the container 14. To unload the spoil from the container 14 the latter is withdrawn along the pipe string 6 back into the trench 2.
A drive unit 16 connected to the container 14 serves to drive both the conveyor worm 15 and the boring head 13. Conveniently, the unit 16 drives a rotary shaft 22 which extends through the container 14 and bears a spiral flight 23 providing the worm 15 and to which the boring head 13 is secured. The latter can be embodied as a single replaceable cutter of optional design with an additional centering cutter 25 all mounted on a common carrier 24 fixed to the shaft 22. The unit 16 preferably incorporates means 17 for displacing the container 14, the head 13, the conveyor worm 15 and the unit 16. To facilitate this displacement the container 14 is equipped with running wheels 18 or the like which engage directly with the interior of the pipe section 7 and the other pipe sections although guide rails can be provided on which the container 14 can run. A cable or chain 19 acting as traction means is provided in the pipe string to displace the container 14 and the ancilliary parts and the means 17 would then incorporate drive and deflection i.e. guide wheels 20 for the cable 19.
Energy is best supplied to the unit 16 by means of supply lines such as hydraulic flexible conduits or hoses 21 leading through the pipe string 6 back to the trench 2 or elsewhere to a pump and control unit. The hoses 21 are best wound around drums which take up and unreel the hoses as the container 14 is moved back and forth between its forward working position and the trench 2. When the container 14 is moved back into the trench 2 for unloading the spoil can be removed in various ways. For example, the container 14 could be simply tipped or turned about its axis or provided with an openable discharge aperture preferably at the bottom. The worm 15 can be run again to assist in unloading. FIG. 5 shows an aperture 26 in the container 14 closed by a flap 27 mounted on a guide 28 for pivoting or sliding.
It is desirable to hold the container 14 in position whilst filling takes place and to achieve this bracing means 29 is provided at the rear of the container 14 near the unit 16. The container 14 is equipped with projections 36 on its front end conveniently spaced by 90° around the periphery of the container 14. These projections 36 are engageable with a shoulder 37 on the cutter shoe 9. The bracing means or device 29 is constructed as two assemblies 30 positioned on diametrically opposed sides of the container 14. Each assembly 30 is composed of two piston and cylinder units 31 mounted in generally parallel disposition with the axis of the pipe string 6. The units 31 are supported on pivot joints 32 with vertical axes permitting them to swing laterally. A further transverse piston and cylinder unit 33 serves to displace the assemblies 30 about the joints 32. As the unit 33 extends the units 31 are swung outwards to engage within recesses or pockets 35 in the interior of the pipe section 7. The rear ends of the recesses 35 form stops 34 for the units 31. When the units 31 are located against the stops 34 by the operation of the unit 33, the units 31 can be extended to urge the container 14 forwardly to bring the projections 36 against the shoulder 37 and effect the bracing operation. The bracing device 29 also permits the shoe 9 to be steered to some extent to correct any deviation in the pipe driving and any tendency for the string 6 to wander off course. To achieve this, lining pieces 38 of varying thickness are interposed between the projections 36 and the shoulder 37 to bring the axis of the shoe 9 into a desired location. The lining pieces 38 are best detachably fixed to the projections 36 when the container 14 is accessible in the trench 2. An alternative arrangement is to provide the projections 36 with some adjustment in the longitudinal direction of the container 14. When the container 14 is to be withdrawn back down the pipe string 6 to the trench, the unit 33 is retracted to swing the units 31 inwardly to free them from the stops 34. For illustrative purposes FIG. 4 shows the units 31 pivoted inwards into their inoperative position and FIG. 3 depicts the units 31 in the upper part in the operative position and in the lower part in the inoperative position.
FIGS. 6 and 7 depict a modified arrangement using the same reference numerals as in FIGS. 1 to 5. The modified version, has inter alia, an improved version of the boring head 13 and its connection to the drive shaft 22. In this modified construction, the diameter of the boring head 13 is variable so that it can be expanded to perform an over cut in relation to the cutter 10 or it can be contracted to a diameter smaller than that of the shoe 9 and the pipe string 6. This enables the head 13 to be withdrawn more easily with the container 14 through the pipe string 6 back to the trench 2. In this design, the boring head 13 has a carrier 39 with a centre cutter 40 and a pair of cutting devices 41 movable radially inwards and outwards. The devices 41 consist of arms 42 mounted for swivelling on pivot joints 44 on the carrier 39 and supporting rollers, wheels or other cutting tools 43. A mechanism 45 serves to pivot the arms 42 about the joints 44 between an outer working position shown in FIG. 6 and an inner collapsed position shown in FIG. 7. The mechanism 45 is operated by the drive shaft 22. More particularly, the mechanism 45 employs an internally threaded sleeve 46 mounted and fixed to the rear of the carrier 39 in axial alignment with the shaft 22. An externally threaded adjustment member 47, engages in the sleeve 46 and acts through a thrust piece 48 to engage with the inner ends of the arms 42. The thrust piece 48 can be displaced axially by the member 47 to cause the arms 42 to pivot outwardly or inwardly and to hold the arm 42 in the set position. The adjustment member 47 is coupled to the shaft 22 via a selective slidable coupling. The coupling can be composed of a polygonal-shaped socket 50 in the member 47 which receives a correspondingly shaped projection of a tool connectable to the end of the shaft 22. By engaging the tool projection in the socket 50 the shaft 22 can be rotated in one direction or the other preferably at slow speed, to drive the adjustment member 47 along the sleeve 46 in one direction or the other. The tool projection can be engaged in the socket 50 when the container 14 is in the working i.e. filling position to urge the member 47 forwardly and swing the arms 42 outwardly.
The drive connection between the boring head 13 and the drive shaft 22 can also take the form of a selective slidable coupling similar to that used for adjustment of the arms 42. The sleeve 46 is thus provided with a polygonal-shaped socket 51 in an end wall which receives a correspondingly shaped tool projection 52 detachably fixed to the drive shaft 22. The socket 51 is larger than the socket 50 in the member 47 and penetrates through the end wall so that the other smaller tool projection used for displacing the member 47 within the sleeve 46 can pass through the socket 51. The engagement of the projection 52 in the socket 51 rotatably locks the carrier 39 to the shaft 22 to permit rotation of the boring head 13. When the container 14 is moved back to the trench 2 for unloading the boring head 13 can remain in its expanded working position at the face since the shaft 22 can be moved with the container 14 to disengage the projection 52 from the socket 51. Other forms of selective couplings such as latches are employed when it is desired to connect the boring head 13 to the shaft 22 to resist axial separation. Thus, the tool projection 52 can be supplemented by another tool projection of similar shape to the tool projection 52 but additionally equipped with spring biased pins which automatically latch into radial apertures 53 in the walls of the socket 51 when the special tool projection is introduced into the socket 51. By mounting this special tool projection onto the shaft 22 the tool projection can lock with the sleeve 46 to permit the boring head 13 to be displaced along the pipe string 6 with the container 14 and ancilliary equipment. The boring head 13 must first be collapsed to the position shown in FIG. 7 by displacement of the adjustment member 47. The boring head 13 would only need to be moved back into the trench 2 in the case of re-tooling or repair or other maintainence. The nature of the cutting appliances provided on the boring head can be changed to adapt to different operating conditions and the selective coupling between the head 13 and the container 14 means the head 13 can be left in place and only withdrawn in case of need. If the head 13 encounters a serious obstruction, the face 8 can be entirely exposed for inspection and appropriate remedies can be utilized.
As in the embodiment depicted in FIGS. 1 to 5, the shaft 22 carries a spiral flight which forms a conveyor worm 15 which transfers spoil from the head 13 and the shoe cutter 10 into the container 14. In this construction, the worm 15 is composed of a flight section 15A on the shaft 22 extending over substantially the entire length of the container 14 and a separate flight section 15B on the sleeve 46 extending between the head 13 and the open front end of the container 14. The forward flight section 15B is thus an integral part of the boring head 13. The entire assembly composed of the shaft 22, the boring head 13 and the worm with flight sections 15A, 15B, is displaceable forwardly and rearwardly along the container 14. This displacement is effected with a double-acting hydraulic piston and cylinder unit 54 accommodated in a hollow rear end portion of the shaft 22. The piston rod of the unit 54 is connected via a pivot joint 55 to the shaft 22 while the cylinder of the unit 54 is connected to a rotatable disc 56 driven by the drive unit 16. The disc 56 is provided with rotary duct means of known design for transferring pressure medium to and from the unit 54. The cylinder of the unit 54 is locked for rotation to the shaft 22 but axially displaceable relative to the shaft 22 as by a splined or toothed connection 57. By operating the unit 54 the head 13 and the worm flights 15A, 15B can be thrust forwards from the container 14 and the shoe 9 or moved back to provide adjustment of the pre-cut in front of the shoe 9. Also by retracting the head 13 and the worm 15 somewhat relative to the container 14 with the unit 54, spoil collecting in the container 14 can be compressed and the loading capacity of the container 14 can be optimized. | Pipe-driving apparatus used to create a pipe line of small diameter uses a pressing station in an access trench to drive in pipe sections one by one. A boring head and conveyor worm operates at the front of the pipe line in a working pipe section on which a cutting shoe is swivably mounted. The worm is a spiral flight on a drive shaft which runs within an open fronted container on which a drive unit for the boring head and the worm is mounted. Hydraulic bracing units mounted to the container can be swung out and engaged with stops in the working pipe section to brace the container during the filling operation. Projections on the container engage with the shoe and the bracing units can be used to steer the shoe. When the container is filled the bracing units re stowed and the container is withdrawn back down the pipe line to the access trench for discharging the material. | 4 |
BACKGROUND OF THE INVENTION
This invention relates to loading dock technology. In particular, it relates to a safety gate which is placed at loading dock openings to prevent vehicular or foot traffic from falling off the end of the dock and to prevent injury.
Doors of a loading dock are often left in the opened position either for purposes of ventilation or because of the frequency of use of the dock makes closing the door inconvenient. Such loading docks are generally equipped with dock levelers, many of the pit type which when stored in a cross-traffic position allow forklift trucks and workers to traverse laterally across the pit area. When no trailer is parked at the door, there is a possibility that a forklift truck while maneuvering between other doors or aisles can accidentally be backed or driven through an open doorway or fall off the dock into the driveway below. Similarly, a pedestrian walking near a doorway could accidentally step over the edge.
Within loading dock and material handling technology, a number of devices are presently in use which partially address this problem. However, they have several significant deficiencies. One group of technology extends the lip of the dock leveler above dock level in the stored or cross traffic position. The purpose is to erect a barrier at floor level which will prevent a forklift truck from backing or otherwise driving over the edge. Typical of these devices are those found in U.S. Pat. Nos. 4,920,598 and 5,040,258. The devices disclosed therein are derivatives of the so-called "Post Office Lip". In general, the concept is to have a lip which extends above the dock floor when the dock leveler is in the stored, cross traffic position. However, when the dock leveler is actuated and the lip extended, the barrier retracts to thus allow traffic to move in an unimpeded manner over the leveler.
While these devices may serve to prevent a vehicle from rolling off the dock, in actuality it compromises overall dock safety because a pedestrian has to deal with a newly created tripping hazard. That is, these lip extensions are generally fairly low and even if visibly marked extend to a height above the dock which causes a stumbling point for a pedestrian. Moreover, such devices are also pinched-points should the dock leveler require manual intervention in order to actuate and fully raise the lip. Finally, such devices prevent an end-loading operation below dock level.
Moreover, such devices define a rigid barrier with little to no deflection to provide energy absorption. For example, if a forklift truck traveling at 5 miles per hour strikes a barrier which deflects minimally, for example, 0.5 inches the deceleration will be in the order of 18G. A forklift truck typically weighs about 10 thousand pounds and the force of impact would be over 180 thousand pounds exerted against the lip of a dock leveler. Even if this force would not damage the dock leveler itself, the forklift truck or the cargo would be subjected to high deceleration, and could result in serious injury to the forklift truck driver.
SUMMARY OF THE INVENTION
Given the deficiencies in prior art devices, it is a fundamental object of this invention to provide a barrier which not only prevents a vehicle from rolling off the dock but also provides energy absorption to stop the forklift truck with a controlled force and a significantly reduce deceleration.
Yet another object of this device is to provide a barrier which is effective for both pedestrian and vehicular traffic while not creating additional hazards.
Yet another object of this invention is to provide a barrier used at a loading dock in conjunction with dock levelers, which is effective to provide a warning barrier yet, not interfere with dock loading operations at any stage whether the leveler is in the stored cross-traffic position or is in use with a truck at the loading dock station.
These and other objects of this invention are achieved by the use of a pivoting beam which is placed across the door opening. The beam is designed to withstand a predetermined load without deformation yet yield by bending if higher forces are imposed. For example, in accordance with this invention the beam is designed to yield at a force of 8 thousand pounds if applied at the mid point such that a 10 thousand pound vehicle striking the barrier at 5 miles per hour will have a deceleration reduced to only 0.8 g with significant beam deflection.
Moreover, in accordance with this invention the forces of deflection are resisted entirely by the barrier posts so that no impact force is transferred to the dock leveler. Additionally, given the positioning of the barrier, the invention is operative even in loading dock openings where no dock leveler is installed. These and other objects of this invention will be explained in greater detail by reference to the attached figures and the description of the preferred embodiment which follows.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective schematic view of a loading dock door in which a first preferred embodiment of this invention is depicted;
FIG. 2 is a schematic enlarged partial view of the embodiment of FIG. 1 showing details of attachment for the safety gate;
FIG. 3 is a top view of the first embodiment of this invention depicted in FIG. 1 illustrating deflection of the beam upon impact;
FIG. 4 is a schematic partial perspective view of a second embodiment of this invention having a different mode of actuation;
FIGS. 5 and 6 respectively are side views of a third preferred embodiment of this invention wherein, FIG. 5 illustrates the barrier gate in a down position and FIG. 6 illustrates the gate in a vertical stored position; and
FIG. 7 is a view of a fourth preferred embodiment of this invention illustrating a spring mechanism to counterbalance the barrier gate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIGS. 1, 2 and 3, a first preferred embodiment of this invention is depicted. In those figures, numeral 1 represents a dock floor having a recessed pit 2. Conventionally, installed in the pit 2 is a dock leveler 3. The dock leveler is shown in the stored cross-traffic position. It will be understood that at the door opening 5 which is cut into a wall 4, a dock leveler lip hangs pendant from the dock leveler 3.
In accordance with a first preferred embodiment of this invention, the safety gate comprises 2 structural posts 6 and 8. Those structural posts may be steel pipe filled with concrete or some other structure as required. For example, while not shown the structural posts 6 and 8 can comprise angle brackets of steel. They are anchored by suitable means, not shown, into the concrete floor 1. A bracket 7 is attached to the front of post 6. A pivot pin 9 is attached to the side of post 8.
The barrier assembly 10 comprises a beam 11 attached to a pivot housing 12 which is carried by the pivot pin 9. A counterweight 13 is attached to the end of the beam 11 and is placed on the side of the pivot 9 to provide the necessary counter force so that the barrier 10 can be easily raised or lowered. In that regard, as illustrated in FIG. 1, the center of gravity CG of the barrier assembly 10 is located above and to the right of the pivot 9. The center of gravity is thus selected as a function of the size and location of the counter weight 13 to cause this offset of the center of gravity of the barrier assembly with respect to that of the pivot point 9. By so offsetting, the weight of the barrier will cause it to remain in the horizontal position with the end supported by the bracket 7. When the barrier is rotated to the vertical position the location of the center of gravity, CG will be moved to the left of the pivot and thus causes the barrier to remain raised.
The barrier 10 when in a vertical position occupies very little space and thus will not obstruct traffic through the doorway. Moreover, by appropriately locating the support posts 6 and 8 protection for the edges of the door opening occurs. This derivative benefit of the invention is one which provides protection for items such as tracks of an overhead door and corners of the openings which would otherwise be subject to impact damage from a forklift truck. It will be appreciated however that depending on the installation, the second support 6 can be eliminated. The gate 11 can limited in its downward rotation by a stop on post 8, not shown. Deflection of the gate 11, as illustrated in FIG. 3 would result in the gate bearing against the wall 4.
Referring now to FIGS. 2 and 3 additional details of this invention are depicted. In particular, as illustrated in those figures the attachment of the beam 11 to the pivot point 12 is illustrated. It will be appreciated that the barrier 11 itself can withstand significant force such that a severe impact would cause the beam 11 to be severely deformed. The beam 11 is constructed of appropriate materials such as steel or high strength plastic composites to permit a degree of elastic deflection.
However, in accordance with this invention deformation of the beam 11 is accommodated in the design and the yielding by bending does not result in bending force to the pivot pin 9. Thus, while the beam 11 may be subjected to high impact forces, the combination of materials and mounting prevents damage.
FIG. 2 illustrates the construction where the counterweight 13 is attached to two plates 18 and 19. The pivoting housing 12 is attached to the bottom plate 19. The beam 11 is clamped between the two plates by means of bolts 20. The holes in the beam are much larger than the bolts (see FIG. 3) so the beam has significant motion relative to the plates 18 and 19. This construction allows the beam 11 to be deformed, as illustrated in FIG. 3 without damaging the pivoting structure. It also facilitates removal and replacement of the beam if it is severely damaged. The enlarged holes in the beam 11 are shown by the dotted lines 21 in FIG. 3.
Consequently, as illustrated in FIG. 3 the beam 11 may deflect upon impact by a forklift truck shown schematically as element 22. Such impact will cause a deflection of the beam 11 and thus a shifting in the bolts relative to the elongated oversize holes 21 in the beam 11. As can be appreciated then, the beam 11 is clamped by means of the plates 18 and 19 to allow it to be raised but, the beam 11 can shift in the horizontal plane as a consequence of the oversize holes 21 which allow the beam 11 to move relative to the bolts 20. The result is deflection of the beam without damage to the pivot structure because the force is totally resisted then by the barrier posts. This is shown in FIG. 3 by the contact of the beam 11 against the posts 6 and 8.
While the barrier may be easily moved by hand given the counterweight structure, FIG. 4 illustrates a second modification. Those items which are identical to the embodiment of FIG. 1 are retained with the same identifying numerals. FIG. 4 adds a mechanical mechanism of actuation whether it be a hydraulic cylinder or electric actuator. The dotted lines illustrate the position of the barrier in the raised position.
A pin 14 is attached to the back of the weight 13 and a bracket 15 is attached to the post 8. The hydraulic cylinder or electric actuator 16 has one end mounted on the pin 14 and the other end attached to the bracket 15 via a pin 17. The actuator extends to lower the barrier and retracts to raise it.
The unit can thus be raised or lowered by means of push buttons or a selector switch on a control panel not shown, at a remote location. Moreover, limit switches, not shown, may be mounted on the post 8 to detect the position of the barrier and automatically switch off power when the barrier is in the desired position.
An additional advantage of having powered actuation of the barrier 10 is that it may be automatically actuated by another device.
For example, many docks have vehicle restraints such as those described in U.S. Pat. No. 4,988,254 to prevent a trailer from moving away from a dock. The electrical controls of the vehicle restraint and the barrier may be interconnected so that the barrier is automatically raised when the vehicle restraint has been engaged. Similarly, the barrier may be automatically lowered when the vehicle restraint is disengaged. This would thus allow loading and unloading operations when the dock has been secured, that is, when a truck has backed in, has been secured and the loading operation is ready to commence. It would also provide a safety switch by which the gate could not be raised unless a truck was in position.
Such automatic actuation would not depend on human intervention but would prevent the barrier from being raised unless a trailer is secured at the dock. Also, operation of the gate could be keyed to actuation of other equipment such as a door or a dock leveler. Thus, unless the door has been raised, the barrier gate could not be raised, and unless the gate has been raised, the dock leveler could not be operated.
Referring now to FIGS. 5 and 6 a third preferred embodiment of this invention is depicted. In the embodiment of FIGS. 5 and 6 the same numerals as used in the first embodiment are carried forward. FIGS. 5 and 6 illustrate an embodiment employing a secondary barrier 26. Such is attached to the primary barrier 11 to prevent a low cart from slipping under the bar. In order to accomplish this result, a bar 26 is mounted on the support 8 by means of a pin 25. This pin 25 provides the pivot point for the bar 26. The other end of the bar is supported by a link 27 which is attached by two pins 28. Thus, the bar 26 moves with the barrier 11 as illustrated in FIG. 6. In the raised position there is no obstruction with the door opening because the pivot point is located on the barrier 8. While not illustrated, it will be understood that the embodiment of FIGS. 5 and 6 could be powered in a manner illustrated in FIG. 4.
Referring now to FIG. 7, a fourth embodiment is depicted. Those items which are identical to the embodiment of FIG. 1 are retained with the same identifying numerals. FIG. 7 illustrates using a spring mechanism rather than a counterweight to counterbalance the beam 11. A bracket 31 is attached to the beam 11, and a bracket 32 is attached to the post 8. A spring 30 has one end attached to the bracket 13 and the other end to an adjusting bolt 33 which passes through a hole in the bracket 32 and is secured by a nut 34 which can be adjusted to apply the desired tension to the spring 30. The position of the bracket 31, the stiffness of the spring 30 and adjustment of the tension of the spring are selected to provide the necessary counter force so that the barrier 10 can be easily raised or lowered. In addition, the mechanism causes the counter force to vary so that the barrier will remain raised when it is rotated to the vertical position, and will remain lowered when rotated to the horizontal position.
Other modifications of this invention can be practiced without departing from the essential scope thereof. For example, actuation could be linked to operation of the dockleveler. | A barrier for a loading dock having an opening in a wall having a dock leveler positioned in a floor of the loading dock adjacent said opening. The dock leveler has a horizontal position where traffic may cross to adjacent areas of the loading dock. A support is located along a side of the dock leveler. A deformable barrier arm is pivotedly connected to the support by a mounting for movement between a horizontal blocking position and a raised vertical position exposing the opening. The mounting has a pivotal connection to the support to permit the deformable barrier arm to move in a vertical arc for raising and lowering the arm and a loose connection to the barrier arm to permit relative motion between the barrier arm and the mounting upon the application of a horizontal load to the barrier arm. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system and method for improving the visibility of objects within a visual field and in particular to a system and method for use in an automotive vehicle under adverse optical conditions.
2. Description of the Prior Art
Generally, safety requires that the driver of an automotive vehicle be protected from being dazzled by the headlights cast by an automotive vehicle in the opposite lane.
Japanese published unexamined patent application No. 52-101526 discloses a prior art system for shutting out the headlights cast by an automotive vehicle in the opposite lane. This system employs a pair of polarizing filters. One filter can pass only the horizontally- or vertically-vibrating component of the headlight beam and is placed in front of the headlights of an automotive vehicle. The other filter can conversely pass only the vertically- or horizontally-vibrating component of the headlight beam and is placed on the windshield of the automotive vehicle. However, this system is less effective in cases where the vehicle in the opposite land lacks the same polarizing filters as are used on one's own vehicle.
Japanese published unexamined patent application No. 49-72830 or 50-138526 also discloses a system for suppressing transmission of headlights cast by an automotive vehicle in the opposite lane through a vehicular windshield by means of a liquid crystal panel and an electronic circuit for controlling the transmissivity of the liquid crystal panel. However, since this system darkens the entire forward visual field of the vehicle on which the headlights are incident, at the moment the liquid crystal filter transmissivity is reduced the driver of the filtering vehicle may fail to recognize irregularities, obstacles and/or pedestrians crossing or standing in the road within the forward visual field.
SUMMARY OF THE INVENTION
An object of this invention is to provide a system for improving the visibility of objects within the visual field of, e.g. a vehicular driver, during night driving. In order to achieve this object, an optical filter with a predetermined pass band in the visible light range is disposed in front of the eyes of a driver as he sits in the vehicle and a light transmitter, e.g. headlight transmitter transmitting visible light, with frequency components falling within the above pass band, is directed toward objects within the visual field of the driver.
The inventive system can increase the visibility of objects within the visual field illuminated by the light from one's own vehicle even when the light from a vehicle in the opposite lane strikes the eyes of the driver of one's own vehicle under optically adverse conditions, e.g. at night.
In addition, the inventive system protects the driver of one's own vehicle from being dazzled by the light from a vehicle in the opposite lane by means of the optical filter.
Another object of this invention is to provide a method for improving the visibility of objects within the visual field of the driver of a vehicle. In order to achieve this object, this method comprises the steps of optically filtering a first frequency component from visible light directed toward the driver and transmitting visible light with a second frequency component toward objects, the second frequency component falling within the first frequency component.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of a system for improving the visibility of objects within a visual field, applied to an automotive vehicle, according to one embodiment of this invention.
FIG. 2 is a graph of the spectral transmissivity properties of an output filter and an input filter.
FIG. 3 is a diagram of a system for improving the visibility of objects within a visual field, applied to one's own automotive vehicle and an automotive vehicle in the opposite lane, according to another embodiment of this invention.
FIG. 4 is a diagram of an optical system other than the optical system composed of the headlight transmitter and the output filter shown in FIG. 3.
FIG. 5 is a graph of the spectral transmissivity properties of three monochromatic light filters shown in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of this invention will be described below with reference to FIGS. 1 to 5.
As shown in FIG. 1, the first embodiment of a system according to this invention comprises a headlight transmitter 1A disposed at the front end of one's own vehicle 2A, an output filter 3A disposed in front of the headlight transmitter 1A and an input filter 4A disposed in front of the eyes of a driver 7 of one's own vehicle 2A.
The headlight transmitter 1A consists of an incandescent lamp, e.g. a tungsten halogen lamp. The light 5A generated by the headlight transmitter 1A includes a broad range of frequencies.
The output filter 3A is a kind of interference filter with a predetermined pass band or bands as shown in FIG. 2. The transmissive properties of the output filter 3A will be described in detail later. The output filter 3A filters out the visible light 5A to yield filtered light 6A with predetermined frequency components. The filtered light 6A directed toward and illuminating a pedestrian 8 (or other obstacles or irregularities in the road) is reflected by the pedestrian 8 and falls onto the eyes of the driver via the input filter 4A so that the driver 7 can easily recognize the pedestrian 8.
The light-emission capacity of the headlight transmitter 1A is boosted somewhat relative to conventional headlights to ensure adequate illumination throughout the driver's visual field despite the attenuation due to filtering.
The input filter 4A is a kind of interference filter with essentially the same transmission properties as the output filter 3A and is formed on or fixedly attached to the windshield glass. On the other hand, the input filter 4A may include an optical band-pass covering with a wider pass band than that of the output filter 3A. For example, the input filter 4A may be formed by vacuum-depositing a dielectric multilayer onto the windshield glass. Alternatively, the input filter 4A may be formed by vaccuum-depositing a dielectric multilayer onto a transparent film or glass.
The input filter 4A receives the filtered light 6A reflected by the pedestrian 8 or obstacle in the road and the light form the headlight transmitters 1B of a vehicle 2B in the opposite lane.
FIG. 2 is a graph illustrating the light-transmissive properties of the output filter 3A. The x-axis of the graph represents the wavelength of light and the y-axis of the graph represents the light-transmissivity. The solid curve 9 represents the spectral transmissivity of the output filter 3A. The curve 9 reflects three predetermined pass bands 10, 11 and 12 of the output filter 3A wherein the spectral transmissivities of the output filter 3A exhibit a peak value of about 87%. The spectral transmissivity of the output filter 3A outside of these bands is negligible, thus forming cut-off bands 10A, 10B, 11A and 12A. Accordingly, the filtered light 6A consists of only the filtered frequency components falling within the pass bands 10, 11 and 12. The pass bands 10, 11 and 12 are preferably selected so as to yield white light after filtering.
As shown in FIG. 1, since the automotive vehicle 2B in the opposite lane has no output filter in front of the headlight transmitter 1B, the unfiltered light 5B generated by the headlight transmitter 1B falls into the eyes of the driver 7 of one's own vehicle 2A solely via the input filter 4A. The input filter 4A reduces the intensity of the unfiltered light 5B and thus protects the driver 7 from being dazzled by the unfiltered light 5B. If the automotive vehicle 2A did not have the input filter, the unfiltered light 5B could dazzle the driver 7.
FIG. 3 illustrates another embodiment of this invention. The same or similar numerals as in FIG. 1 designate similar elements. The system shown in FIG. 3 differs from the system shown in FIG. 1 in that an automotive vehicle 2B in the opposite lane also has a similar system for improving the visibility of objects within the visual field. In particular, the automotive vehicle 2B has a headlight transmitter 1B similar to the headlight transmitter 1A, an output filter 3B similar to the output filter 3A, and an input filter 4B similar to the input filter 4A. Accordingly, the automotive vehicle 2B in the opposite lane will shine filtered light 6B at the first automotive vehicle 2A.
In addition, in order to increase the effect of the system shown in FIG. 3, it is necessary for the light-transmissive properties of the output filter 3B and the input filter 4B of the automotive vehicle 2B in the opposite lane to differ from those of the output filter 3A and the input filter 4A of one's own automotive vehicle 2A.
The output filter 3B and the input filter 4B possess the spectral transmissivity represented by the broken curve 13 of FIG. 2. The overall configuration of the curve 13 is the same as that of the curve 9 but the pass bands 14, 15 and 16 of the curve 13, which are preferably selected to yield white light in combination, substantially overlap the cut-off bands 10A, 11A and 12A of the curve 9.
Thus, the filtered light 6B from the automotive vehicle 2B in the opposite lane consists only of frequency components corresponding to the cut-off bands, 10A, 11A and 12A of the input filter 4A of one's own vehicle 2A and is therefore highly attenuated by the input filter 4A of ones own automotive vehicle 2A.
Similarly, the filtered light 6A from one's own vehicle 2A consists only of frequency components corresponding to the cut-off bands 14B, 15B and 16B of the automotive vehicle 2B in the opposite lane and is attenuated by the input filter 4B of the automotive vehicle 2B in the opposite lane.
In another embodiment of this invention, the output filter 3A or 3B and the input filter 4A or 4B possess only one pass band, e.g. the central pass band 11 shown in FIG. 2.
In still another embodiment of this invention, the output filter 3A and the input filter 4A employ only one pass band, e.g. the pass band, 11, and on the other hand the output filter 3B and the input filter 4B employ only one pass band, e.g. the pass band, 15, falling outside of the pass band of the output filter 3A and the input filter 4A.
The above output filter 3A or 3B may be formed by means of vaccuum-depositing a dielectric multilayer onto glass or an optical lens.
FIG. 4 illustrates the optical system used in place of the optical system consisting of the headlight transmitter 1A or 1B and the output filter 3A or 3B as described above. This optical system comprises three monochromatic light transmitters 17A, 17B and 17C, one condenser lens 18 and one diffusive lens 19.
The monochromatic light transmitter 17A comprises a light source 20A, a monochromatic light filter 21A and a condenser lens 22A. As before, the light source 20A is a tungsten halogen lamp or other incandenscent lamp and transmits an extensive range of optical frequencies. The monochromatic light filter 21A filters the light transmitted by the light source 20A in accordance with its pass band 23A shown in FIG. 5 to yield essentially monochromatic light. The condenser lens 22A directs the monochromatic light transmitted through the monochromatic light filter 21A to the condenser lens 18.
The respective monochromatic light transmitters 17B and 17C have the same light sources 20B and 20C and condenser lenses 22B and 22C as the monochromatic light transmitter 17A. Monochromatic light filters 21B and 21C are similar to the monochromatic light filter 21A, but the pass bands 23A, 23B and 23C differ from one another and are very narrow, as shown in FIG. 5. The spectral transmissivities of the monochromatic light filters 21A, 21B and 21C are all about 70%. The optical axes of all the monochromatic light transmitters 17A, 17B and 17C are directed toward the center of the condenser lens 18.
The condenser lens 18 receives three monochromatic beams from the respective monochromatic light transmitters 17A, 17B and 17C and transmits the composite beam of light to the diffusive lens 19 which is arranged coaxially with the condenser lens 18. The light transmitted through the diffusive lens 19 is cast forward as a headlight beam into the visual field of the driver. The pass bands 23A, 23B and 23C are preferably selected so as to yield white light when combined by the condenser lens 18.
Alternatively, the monochromatic light transmitters 17A, 17B and 17C may be lasers generating three laser beams at different wavelengths. Alternatively, the monochromatic light transmitters 17A, 17B and 17C may be sodium-vapor lamps generating three light beams at different wavelengths. Lasers or sodium-vapor lamps can produce relatively tight light beams, which would reduce the number of convergent lenses and monochromatic filters needed in the optical system. | Disclosed are a system and a method for improving the visibility of objects within the visual field of a vehicular driver while driving under optically adverse conditions. The system includes an optical filter with a pass band in the visible light range disposed in front of the eyes of the driver, and a light transmitter sending out a beam of visible light with frequency components within the pass band toward the object. In addition, this system protects the driver from being dazzled by light from an approaching vehicle in the opposite lane. The method includes the steps of allowing transmission of visible light with a first frequency component to the driver and transmitting visible light with a second frequency component into the visual field, the second frequency component being a subset of the first frequency component. | 6 |
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