description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
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TECHNICAL FIELD
The present invention relates to a steering column switch for motor vehicles having a switch housing and a switch lever mounted therein to be pivoted about a pivotal axis together with a switching member, which switch lever has at least one read-out panel which may be fully illuminated by a light guide extending along the switch lever, which light guide is aligned to a light source by a light-input area.
BACKGROUND OF THE INVENTION
Since it has become normal practice for a long time to equip electric switches arranged on a motor vehicle instrument panel with a lighting system, steering column switches with illumination have also been used in particular vehicle models in the last few years. A steering column switch with illuminated switch lever is known from the printed specification of European patent 0 160 905. Several light emitting diodes are arranged as light sources in the switch lever of the steering column switch according to that printed specification. Among other things, it is disadvantageous to arrange a light source in the switch lever because the light source is then exposed to hard impacts as the switch lever is switched on and.
A steering column switch has also become known in which the switch lever includes read-out panels, which may be illuminated by light guides extending along the switch lever and which are aligned to a light source by a light-input area. In a construction of this kind the light source can in principle be arranged in any desired place.
The present invention addresses the problem of arranging a light source, from which at least one light guide is conducted to at least one read-out panel in the switch lever of a steering column switch, in such a way that the light source is protected and that together with the steering column switch a compact structural unit is formed.
SUMMARY OF THE INVENTION
This problem is solved by a steering column switch constructed in accordance with the present invention.
A construction is preferred in which the entire light guide including the light input area is held on the switch lever and switching member and can be pivoted together with the switch lever and switching member. This has the advantage that the light guide is not continuously bent to and fro when the switch lever and switching member are jointly pivoted.
It is of special advantage to arrange the light source centrally around the pivotal axis of the switch lever and switching member. In such an arrangement the relative position between the light source and the light input area of the light guide is the same with regard to the pivotal axis mentioned in every switching position of the switch lever and the read-out panel can be illuminated with the same intensity in every switching position of the switch lever. It is conceivable, for example, to axially align the end of the light guide which is close to the light source and to put it on the pivotal axis. Because the switch lever protrudes more or less radially from the switch housing towards the pivotal axis, it is more favorable if, the light guide is radially aligned with the light source around the pivotal axis of the switch lever. When the switch lever is pivoted, the light-input area of the light guide is moved around the light source with constant spacing.
Normally the switch lever, in particular the switching member, is mounted on the switch housing by at least one bearing pin and one bearing ring. In principle it is possible that, looked at from the switching member in the axial direction, the light source is located in the switch housing beyond the bearing pin and bearing ring. However it is more favorable, if the bearing pin has a hollow, in which the light source can be fitted or into which the light source can project. Thus a compact mode of construction is achieved. Furthermore the end of the light guide which is close to the light source can be close to the switch lever. Preferably, a hollow bearing pin or a bearing ring on the switching member is closed by a bottom to form a hollow in the switching member into which hollow the switch lever projects. Thereby the light source is almost completely covered in its hollow, so that no external light can emerge.
The hollow in which the light source is located is accessible for the light guide through an opening. Preferably, the bearing pin and bearing ring overlap in the vicinity of the light guide in the axial direction. If the bearing ring and bearing pin overlap in the vicinity of the light guide, the opening in the bearing element attributed to the switch housing is so big, that, when the switch lever and switching member are rotated in the opening the light guide is moved in a peripheral direction relative to the pivotal axis of the switch lever.
The light guide can be fixed in the switching member by its end close to the light source. It is however also conceivable to fix it on the switch lever. This is preferred if the switch lever can be pivoted relative to the switching member about a second pivotal axis extending perpendicularly to the pivotal axis in common. In order to allow actuation of the switch lever without strain for the light guide, the end of the light guide close to the light source can be moved relative to the switching member and switch housing when the switch lever is pivoted about the second pivotal axis. Thus in particular the openings in the bearing pin and bearing ring are so big that they permit movement of the light guide when the switch lever is pivoted about a second pivotal axis.
In order to assure that no external light can emerge from the openings in the bearing pin and bearing ring, these openings are preferably covered by the switch lever.
In its longitudinal direction the light guide can be fixed in a particularly simple way, if it has a wedge located near one end by which wedge the light guide is positioned in a corresponding recess. This arrangement of the light guide longitudinally can also be advantageously applied independently of other features of the present invention.
Two embodiments of a steering column switch according to the present invention are shown in the drawings. The invention will now be described in detail by reference to these drawings, in which:
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a longitudinal section through a first embodiment of the present invention, in which the light source is put in a separate holder inserted in the switch housing;
FIG. 2 is a top view of the embodiment shown in FIG. 1, with the cover removed from the switch housing; and
FIG. 3 is a section similar to that of FIG. 1 through the second embodiment of the present invention in which the light source is directly inserted in the switch housing.
DETAILED DESCRIPTION
The housing 10 of the steering column switch shown in FIGS. 1 and 2 has a rectangular frame 11, which at one side is closed by a cover 12 and at the other side by a bottom 13. In the interior of the switch housing 10 is located a plate 14 spaced from the bottom 13, which plate carries several microswitches 15 which can be operated by pivoting the switch lever 20 and of which two can be recognized in FIG. 1. A switching member 21 is mounted in the housing 10 in such a way that it can be pivoted about an axis 22, which in FIG. 2 is shown perpendicular to the drawing plane. The frame 11 and the cover 12 have two bearing rings 23 and 24, respectively, for mounting purposes, the axes of which bearing rings are flush with each other. However the internal diameter of the bearing ring 23 in the frame 11 is much larger than the internal diameter of the bearing ring 24 in the cover 12. The switching member 21 engages the two bearing rings through two bearing pins 25 and 26, respectively. The external diameters of the bearing pins 25 and 26 are adapted to the internal diameters of the bearing rings 23 and 24. Whereas the bearing pin 26 is made of solid material, the bearing pin 25 is hollow and only its cylindrical wall fits inside the bearing ring 23 of the frame 11.
The switch lever has a plastic support 30 into which is pressed a thin metal pin 31 projecting into a hollow or bore 32 of the switching member 21. The metal pin 31 and thus the entire switch lever 20 is supported relative to the switching member 21 through a bearing pin 33 in such a way that lever 20 may be pivoted about an axis 34 relative to the switching member 21, which axis 34 crosses the axis 22 perpendicularly. When operated perpendicularly to the drawing plane of FIG. 1, which is usually designated as operation in a horizontal plane, the switch lever 20 is thus always moved together with the switching member 21. When operated perpendicularly to the horizontal plane, which is usually designated as operation in a vertical plane, the switch lever is moved alone. In the horizontal plane the various switching positions of the switch lever 20 and of the switching member 21 are defined by a locking curve 35, which is positioned on a pivotal locking lever 37 being supported on the switch housing 10 through a spring 36. In the vertical plane the switching positions of the switch lever 20 are defined by a locking curve 39 on the switching member 21 and by a locking pin 40, which projects from a pocket bore 41 located on the side of the metal pin 31 facing away from the plastic support 30 and is supported on the bottom of the said pocket bore 41 by a pressure spring 42.
The plastic support 30 of the switch lever 20 is hollow to a substantial extent. Within its interior, support 30 contains a printed circuit board 50, on which a microswitch 51 and possibly other electric components not shown in detail are fitted. On the open front side of support 30 opposite the switch housing 10, a structural unit is fitted in the plastic support 30. The structural unit includes a fastening sleeve 52, a push button 53 which can be displaced relative to the fastening sleeve in the longitudinal direction of the switch lever 20 and is fixed on the fastening sleeve 52, and a helical compression spring 54 which is supported between fastening sleeve 52 and push-button 53. The push-button 53 extends beyond the bottom of the fastening sleeve 52 where detents 55 ensure attachment a finger 56 can operate the microswitch 51.
On the side which faces the vehicle driver, the plastic support 30 has a read-out panel 60 adjacent the push-button 53, which read-out panel abuts a read-out panel 61 on the push-button 53. Both read-out panels 60 and 61 are illuminated by a flexible light guide 62, which is positioned behind the read-out panels 60 and 61 by the fastening sleeve 52. In the longitudinal direction the light guide 62 is fixed on the fastening sleeve 52 by means of wedges 63. Inside the plastic support the light guide 62 extends to the switch housing 10, where light radiated from a light source 65 enters the light guide 62. The light source 65 is an incandescent lamp which is secured in a separate holder 66 and together with the latter it is fitted in the switch housing through an opening in the bottom 13. The incandescent lamp projects through an aperture in the plate 14 into the hollow 67 of the bearing pin 25. The axis of the incandescent lamp 65 coincides with the pivotal axis 22 of the switch lever 20 and of the switching member 21. The incandescent lamp 65 is held in the switch housing 10 by a tapered fit between holder 66 and plate 14. A flange 68 on the holder 66 covers the aperture 69 in the plate 14 towards the outside. The hollow 67 in the bearing pin 25 is also closed, towards the hollow 32 in the switching member 21, by a bottom 70. Thereby external light is prevented from emerging between switch housing 10 and switch lever 20.
In order to assure that the light guide 62 can reach the hollow 67 in which the incandescent lamp 65 is positioned, the bearing ring 23 has an opening 75 at the side facing the plastic support 30 of the switch lever and the bearing pin 25 has an opening 76, which receives the light guide using a snug fit and through which, with respect to the pivotal axis 22, the light guide 62 is radially aligned with the incandescent lamp 65. When the switch lever 20 and the switching member 21 are pivoted about the axis 22 the end 79 of the light guide 62 facing the incandescent lamp 65 is carried along by the bearing pin 25. Because the incandescent lamp 65 is centrally arranged and faces light-input area 64 on end 79, the illumination of the read-out panels 60 and 61 is not affected. The opening 75 in the bearing ring 23 is sufficiently large in the peripheral direction of the pivotal axis 22 that the bearing pin 25 can carry the light guide 62 without impedance.
When the switch lever is pivoted in the vertical plane, the end of the light guide 62 close to the incandescent lamp 65 retains its position, because it is fixed on the switching member through a snug fit in the opening 76 of the bearing pin 26. The small angular movement of the switch lever 20 is compensated by a slightly changed position of the light guide 62 within the plastic support 30.
In the embodiment shown in FIG. 3, the frame 11 of a housing 10 also includes a bottom and is only closed by a cover 12. Similar to the construction according to FIGS. 1 and 2 a switching member 21 is supported by bearing pins 25 and 26 and bearing rings 23 and 24 in such a way that it may be pivoted together with the switch lever 20 in a horizontal plane about the axis 22. In addition the switch lever 20 can also be pivoted relative to the switch housing 10 and the switching member 21 about an axis 34 in a vertical plane.
With regard to bearing ring 24 and bearing pin 26 the switching member 21 is similarly supported in the switch housing 10 as in the embodiment shown in FIGS. 1 and 2. However the hollow bearing pin 25, in constrast to the embodiment shown in FIGS. 1 and 2, is formed on the frame 11 of the switch housing 10 and fits inside bearing ring 23 on the switching member 21. The bearing ring 23 is closed by a bottom 70, similar to the pin 25 of FIGS. 1 and 2, towards a hollow 32 in the switching member 21 for receiving the switch lever 20. A capless incandescent lamp 65 is used as a light source, the connecting wires 77 of which are soldered with plug terminals 78 fitted in the housing 10. The incandescent lamp is again centrally arranged around the axis 22 in the space 67 formed by the bearing ring 23 and the hollow pin 25. Lamp 65 projects farther into the bearing ring than the bearing pin 25.
On the side of the bearing ring 23 extending in the direction of the switch lever 20 between the bottom 70 and the bearing pin 25 is located an opening 75, through which the combined end 79 of several light guides 62 extends into the hollow 67. In contrast to the embodiment shown in FIGS. 1 and 2, in the embodiment shown in FIG. 3 there is thus only one opening for the light guide necessary in the bearing element of the switching member 21, namely in the bearing ring 23.
In contrast to the embodiment shown in FIGS. 1 and 2, in the embodiment shown in FIG. 3 the end 79 of the light guide 62 is not fixed on the switching member 21, but on the switch lever 20. The opening 75 in the bearing ring 23 is somewhat larger than the cross-section of the end 79 of the light guide 62, so that the end can move in the opening 75 when the switch lever 20 is pivoted about the axis 34 relative to the switching member 21.
In order to ensure that no light can emerge, the opening 75 is covered by the switch lever 20 in the manner of a mesh. The opening 75 is surrounded by a collar 80 which projects in a circumferential recess 81 on the switch lever 20. | A steering column switch for motor vehicles includes a switch housing and a switch lever mounted therein which may be pivoted about an axis together with a switching member, which switch lever is provided with at least one read-out panel which may be illuminated by a light guide traversing the switch lever, which light guide is aligned with a light source by a light-input area. The light source is fitted and protected in the switch housing; it is free from hard switching-on and switching-off impacts of the switch lever. In particular, it is arranged centrally around the pivotal axis of the switch lever and switching member, so that it is possible to illuminate the read-out panel with the same intensity in all switching positions of the switch lever relative to the pivotal axis. | 1 |
BACKGROUND OF THE INVENTION
The invention herein described was made in the course of or under a contract thereunder with the United States Air Force Systems Command.
The invention relates to the catalytic codimerization of norbornadiene, hereinafter referred to as NBD, and acrylonitrile, hereinafter referred to as AN. Particularly, the invention relates to the preparation of a codimer using a specified catalyst system.
The codimer can be used as a precursor for a missile fuel. The codimer contains a nitrile which can be hydrolyzed to an acid which can be decarboxylated. The resulting decarboxylated hydrocarbon can be used as a missile fuel.
NBD is also known as bicyclo-(2.2.1) heptadiene-2,5. A method of preparation is disclosed in U.S. Pat. No. 2,875,256 issued Feb. 24, 1959. The latter can be represented by either one of the following structural formulas: ##STR1##
NBD can be easily dimerized to a exo-exo hexacyclic dimer. Thus one problem in reacting NBD with another hydrocarbon reactant is to minimize the formation of the foregoing dimer while encouraging the formation of the desired codimer.
In the Journal of the American Chemical Society /97:4/ Feb. 19, 1975, pages 812 & ff, R. Noyori et al in an article titled "Nickel (O)-Catalyzed Reaction of Quadricyclane with Electron-Deficient Olefins" discloses the reaction of NBD and AN using bis(acrylonitrile)nickel(O). The resulting codimer product has the following structure: ##STR2## The reaction was run at a temperature of 40° C for a substantial amount of time. Yet the yield of codimer II was low.
Thus, as the aforementioned work indicates, the specific problem is to obtain codimer II in both a high conversion and selectivity and with a rapid reaction rate.
SUMMARY OF THE INVENTION
Rapid codimerization of NBD and AN is obtained using a catalytic amount of a three-component homogeneous catalytic system consisting of nickel acetylacetonate, triphenylphosphine ((C 6 H 5 ) 3 P), and an alkyl aluminum chloride. The nickel compound can be the hydrate (2H 2 O) or be the anhydrous form. Both the yield and selectivity as to codimer II are excellent and the reaction rate is relatively rapid. Resulting codimer can be a precursor to a missile fuel.
DESCRIPTION
The nickel acetylacetonate, is hereinafter referred to as NiA 2 ; the triphenylphosphine as TPP and the alkyl aluminum chloride as AAC.
The catalytic codimerization of NBD and AN via present invention can be represented by the following formula reaction: ##STR3## As shown NBD and AN are contacted in the presence of the catalyst system defined herein. Codimer II is a tetracyclic nitrile having the molecular formula C 10 H 11 N.
The NBD used can contain a nominal amount of similar hydrocarbons, however, which if present should not be of a type which could adversely effect the reaction. If the NBD used contains such an undesirable hydrocarbon it can be removed by known means. The foregoing also applies to the AN used. Thus, the reactants used in the invention can consist essentially of NBD and AN.
In the codimerization of NBD and AN 1 mole of each reacts with the other to form 1 mole of the NBD-AN codimer II. However, if the NBD to AN mole ratio is too large, homodimerization can occur with its adverse effect on yields. On the other hand if the NBD to AN mole ratio is too low then the yield per pass can be too low and hence, uneconomical. Within the aforementioned limits a preferred NBD to AN mole ratio is in the range between from about 0.1 to about 20 with about 0.2 to about 5 more preferred.
The catalytic system favoring the aforementioned codimerization reaction (A) contains three components. All three components of the catalyst system are commercially available and methods for their preparation are reported in the literature. The three are NiA 2 , TPP and AAC. The AAC can be selected from the group consisting of diethylaluminum chloride, ethyl aluminum dichloride and ethyl aluminum sesquichloride. The latter three are hereinafter referred to as DEAC, EADC and EASC, respectively. The amount of the system present is a catalytic amount so that a suitable conversion to codimer II occurs and the selectivity as to it is sufficient. Material, which during the codimerization reaction could adversely affect the catalyst system, should not be present. For example, the presence of hydroxylic compounds such as water, alcohol or oxygen from air could deactivate the catalyst system.
The amount of NBD present compared to the NiA 2 is catalytically sufficient to obtain the desired product. Generally, the NBD to NiA 2 mole ratio can range between from about 10 to about 2000 with a preferred range between from about 20 to about 1000.
The second component of the catalyst system is TPP which has the following formula: (C 6 H 5 ) 3 P. The amount of this second component of the catalyst system should be catalytically sufficient to obtain the desired product. The amount of the second component can vary substantially but generally it is related to the amount of NiA 2 present. An operable TPP to NiA 2 mole ratio can range between from about 0.1 to about 100 with 0.25 to about 20 more preferred.
DEAC, EADC or EASC is the third component of the catalyst system with DEAC preferred. The amount of the third component can vary substantially but generally it relates to the amount of NiA 2 used. An effective DEAC, EADC or EASC to NiA 2 mole ratio can be between from about 1 to about 100 with from about 3 to about 50 preferred and from about 5 to about 20 more preferred. Excess DEAC, EADC or EASC also serves as a scavenger. Generally, however, when DEAC, EADC or EASC is used it is advantageous to conduct the reaction under substantially anhydrous conditions and under an inert gas blanket.
Selectivity refers to the amount of a particular compound formed divided by the amount of all compounds formed. From a commercial standpoint economics of an overall process determines the optimal levels for both the selectivity and yield.
The reaction time required for an economically satisfactory selectivity and/or yield depends on a number of factors, such as catalyst to feed ratio, as well as operating conditions. Also the economics depend on capital investment versus conversion per pass and the like. The catalyst to feed ratios are discussed herein while typical conditions are provided by the Example.
A solvent can be used in the codimerization reaction. The solvent can be inert or it can be the NBD itself. Since the reaction is mildly exothermic the solvent can serve as a heat sink. It can also assist in solubilizing the reaction components, that is, the feed and the components of the catalyst, and thereby provide for a homogeneous reaction medium. Some solvent can be added to the system as a carrier for one or more of the catalyst components. For example, DEAC is often maintained in a solvent such as toluene. Furthermore, the solvent should not adversely react with the feed, products or catalyst, therefore, if it is not NBD, it should be inert. Also, presence of the solvent can facilitate the handling of the reaction mixture. Classes of suitable inert solvents include aromatic hydrocarbons, cycloparaffins, cycloolefins, ethers, halogenated aromatics, halogenated paraffins and halogenated cycloparaffins. Specific examples include benzene, toluene, xylenes, cyclohexane, cyclopentene, diethylether, chlorobenzene, bromobenzene, chlorinated cyclohexane and the like. As to the amount of solvent used, excessive amounts decrease the reaction rate, and thus, adversely affect the economics for a commercial operation.
The codimerization of NBD and AN with the three-component catalyst system can occur at ambient temperature. Thus, the temperature of the homogeneous feed catalyst system mixture need not be raised to initiate reaction (A). If the mixture is at an extremely low temperature, then heating of the mixture could be necessary. If the temperature increases too much then some cooling would be required. Generally, however, the codimerization of NBD and AN with the three-component catalyst system is not characterized by an extremely rapid exotherm when a reasonable amount of catalyst is used.
Selective codimerization of the NBD and AN occurs in a liquid phase, therefore it is not desirable to have the reaction temperature largely exceed the boiling points of the NBD and/or any solvent. Conversely, if the temperature is too low the reaction rate would be too low to be economically feasible. An operable temperature range is between from about -20° C to about 100° C with about 25° C to about 85° C a preferred range. The operating pressure can vary substantially, however, it can range from about atmospheric up to about 2000 psi with 1000 psi a preferred upper value. Process economics favor lower operating pressure, however, a moderately elevated reaction pressure may be desirable to keep the AN in solution.
To further illustrate the invention, the following examples and comparisons are provided.
EXAMPLES
Into a glass reaction vessel were added 0.033 millimoles of NiA 2 hydrate and 0.168 millimoles of TPP (0.12 molar in benzene) all at 24° C and then deaerated. Then 4.93 millimoles of NBD were added and the mixture was warmed to 53° C and then cooled to 33°. To the vessel were then added 0.70 millimoles of DEAC (1 molar in benzene). Then 14.8 millimoles of AN were added to the vessel. After 456 minutes the reaction mixture was quenched and a catalyst-free sample of product analyzed by vapor phase chromatographic analysis (vpc). The analysis indicated that 53.7 wt. % of the NBD was converted with an 85.5% selectivity to codimer II. Also the vpc indicated that about 34.7% of the AN was converted with about a 44% selectivity to codimer II. The total product yield was about 45.9 wt. %. A run using just NiA 2 and DEAC failed to yield codimer II.
Comparative runs were made using the following catalyst systems: cobaltic acetylacetonate and DEAC and TPP; CoA 3 , DEAC and 1,2 bisdiphenylphosphino ethane; ferric acetylacetonate, DEAC and TPP; and rhodium acetylacetonate, DEAC and TPP. The first two catalyst systems yielded Binor-S as the major product. The next two catalyst systems yielded no major codimer product. | Norbornadiene and acrylonitrile are catalytically codimerized in the presence of a three-component homogeneous catalytic system consisting of nickel acetylacetonate, triphenylphosphine and an alkyl aluminum chloride. The codimer can be used as a precursor for missile fuel. | 2 |
This application is a continuation of application Ser. No. 884,924, filed July 10, 1986, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device manufacturing apparatus for manufacturing semiconductor devices on semiconductor substrates and more particularly, it relates to an improvement of a semiconductor device manufacturing apparatus including a vertical type of heating furnace for forming films on semiconductor substrates.
2. Description of the Prior Art
In the past, various semiconductor device manufacturing apparatus have been known for forming films, such as oxide films, nitride films, polysilicon films, on silicon substrates or the like for forming a semiconductor device. As such semiconductor device manufacturing apparatus, various oxidizing equipment and CVD (Chemical Vapor Deposition) equipment have been used.
Such semiconductor device manufacturing apparatus comprise a horizontal heating furnace, and others comprise a vertical heating furnace. The structure of a horizontal heating furnace is disclosed in, for example, an article by L.E. Katz et al. entitled "High Pressure Oxidation of Silicon by the Pyrogenic or Pumped Water Technique", Solid State Technology, Dec. 1981, pp 87-93. In forming films, a plurality of semiconductor substrates are disposed approximately vertically in a horizontal heating furnace, whereas semiconductor substrates are juxtaposed horizontally with predetermined spacings in a vertical heating furnace.
FIG. 1 is a diagram showing a holder used for holding silicon wafers in a conventional vertical heating furnace. As a material of this holder, for example, quartz, silicon carbide, or polysilicon is used. In FIG. 1, each of three supports 8 of a holder 7 is formed with grooves 9 for inserting silicon wafers 1 in a longitudinal direction of each of the supports 8, with a predetermined spacing between grooves. The silicon wafers 1 are inserted into the grooves 9 one by one and then are placed within a vertical heating furnace of a semiconductor device manufacturing apparatus to be heated. Then, raw material gas for forming films on the silicon wafers 1 is introduced into this vertical heating furnace.
In a conventional semiconductor device manufacturing apparatus, a holder of silicon wafers is constructed as described above. If silicon wafers are inserted into grooves of the holder, a part of the silicon wafers inserted into the grooves becomes covered by a part of the support. This causes a problem in which the films formed do not grow uniformly, because raw material gas for forming films do not sufficiently reach this portion, and a difference in film thickness occurs on the surface of silicon wafers.
There also has been a problem in which this portion is contaminated by bringing a part of silicon wafers into contact with the edge of grooves by mistake in inserting silicon wafers into grooves.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide a semiconductor device manufacturing apparatus which drastically improves uniformity of thickness of films formed on the surface of semiconductor substrates, as well as can prevent the contamination of the surface caused in inserting the semiconductor substrates.
Briefly stated, the present invention is directed to a heating furnace for forming films on semiconductor substrates, in which holding means for holding semiconductor substrates are provided with projections for holding at least part of the bottom faces of semiconductor substrates horizontally, with predetermined spacing between the projections.
In accordance with the present invention, raw material gas flows uniformly over semiconductor substrates, resulting in films having uniform thickness.
These objects and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing a holder for conventional semiconductor substrates.
FIG. 2 is a diagram showing a holder for semiconductor substrates of an embodiment of the present invention.
FIG. 3 is a diagram showing a holder for semiconductor substrates of another embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 2 is a diagram showing a holder for semiconductor substrates used in a semiconductor device manufacturing apparatus of an embodiment of the present invention. The holder comprises for example three supports, although they are not illustrated in FIG. 2. In FIG. 2, the respective supports 2 of this holder are provided with projections 3 horizontally relative to a longitudinal direction of each of the supports, with predetermined spacing between the projections 3, and semiconductor substrates, such as silicon wafers 1 are disposed approximately horizontally on these projections 3. Projections 3 may be provided so that silicon wafers 1 can be supported completely in the horizontal direction. However, in such a case, the silicon wafers 1 can cause rotational motion during formation of films and hence, to prevent this, projections 3 are provided so that silicon wafers 1 can be supported while slightly inclined. The spacings between projections 3 as disposed horizontally is such that raw material gas of films to be formed on the surface 11 of silicon wafers 1 flows smoothly.
Since in the present invention the semiconductor substrates are supported by the projections, as described above, instead of conventional grooves, raw material gas flows uniformly on the semiconductor substrates, permitting formation of films having uniform thickness.
FIG. 3 is a diagram showing another embodiment of the present invention. In FIG. 3, supports 4 of a holder are provided with projections 5 longer than projections 3 shown in FIG. 2. Projections 5 are provided with stepped portions 6, and silicon wafers 1 are engaged with these stepped portions 6. The location of projections 5 between supports 4 and the spacings between projections 5 are similar to the embodiment shown in FIG. 2. That is, projections 5 are arranged with such spacings that silicon wafers 1 can be held horizontally or with slightly inclined, and raw material gas can flow uniformly on the silicon wafers.
Since in the holder shown in FIG. 3 in comparison with the holder shown in FIG. 2, silicon wafers 1 are provided away from supports, the flow of raw material gas becomes more uniform.
As a material of the holders shown in FIG. 2 and FIG. 3, quartz, silicon carbide, polysilicon or the like is usually used, but it is not intended to be limited.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. | In a heating furnace for forming films on semiconductor substrates (1), holding means (2, 4) for holding semiconductor substrates (1) are provided with projections (3, 5) for holding at least part of bottom faces of the semiconductor substrates (1) horizontally with predetermined spacing between the projections. | 2 |
BACKGROUND OF THE INVENTION
The present invention relates to a carrousel apparatus for manufacturing, by compression molding, plastics items.
Compression molding apparatuses generally comprise a carrousel, which can rotate about a vertical axis and on which a plurality of angularly spaced molding units are installed. Each unit comprises an upper male element (plug) aligned with a lower female mold part (cavity).
In order to obtain the item, a dose of semifluid plastics is introduced in the female mold part and is pressed by means of a relative movement of the two mold parts in order to obtain the item.
In the manufacture of caps for closing containers provided with internal undercuts (for example screw caps), the molded cap, after the mold parts have been opened, remains attached to the plug and is removed by means of an ejector, utilizing the elasticity of the plastics that has not yet hardened.
In the case of caps having external undercuts, it is not possible to perform removal by simply pushing downward the ejector, since the cap cannot retract inward.
SUMMARY OF THE INVENTION
The aim of the present invention is to obviate the above cited drawbacks of known devices, i.e., to provide a carrousel apparatus provided with means that allow to form items, particularly hollow items, such as caps provided with raised portions and undercuts on their outer surface.
Within this aim, an object of the present invention is to provide an apparatus in which the cap forming means assist the extraction of the molded caps from the mold.
This aim and this object are achieved by the present apparatus, whose characteristics are defined in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics and advantages will become better apparent from the detailed description of a preferred but not exclusive embodiment of a carrousel apparatus for manufacturing screw caps by compression molding of plastics, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
FIG. 1 is a sectional view, taken along a vertical plane, of a molding unit of the apparatus;
FIG. 2 is an enlarged-scale view of the upper part of the unit of FIG. 1;
FIG. 3 is an enlarged-scale view of the lower part of the unit of FIG. 1;
FIG. 4 is a sectional view of a detail of the unit of FIG. 1;
FIG. 5 is a sectional view, taken along the line V—V of FIG. 4;
FIGS. 6, 7 and 8 are views of the lower part of the unit in three successive operating conditions;
FIGS. 9 and 10 are two sectional views, taken along a vertical plane, of the lower part of a second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIGS. 1 to 5 , the apparatus is constituted by a carrousel, which rotates about a vertical axis Z and supports peripherally a plurality of units S for the molding of caps that consist of screw caps A made of plastics. One of said caps is illustrated more clearly in FIG. 8 .
Hereinafter, it is assumed that said caps A are composed of a cup B provided with an internal thread C and of a tamper-evident band D provided with inner teeth E and with an outer annular ridge F. The band D forms, together with the rim of the cup, an outer step G.
Each unit S is composed of an upper male mold part, generally designated by the reference numeral 1 , and of a lower female mold part, generally designated by the reference numeral 2 , which are mutually coaxial along an axis X that is parallel to the axis Z. The female mold part 2 can be actuated against the male mold part 1 by means of a hydraulic jack, which is not shown.
The male mold part 1 comprises a plate 3 (see FIG. 3 ), which is screwed, by means of a tubular tang 4 , into a sleeve 5 b , which is in turn screwed to the lower end of a sleeve 5 a so as to form a single hollow stem 6 (FIG. 1 ).
A hollow tube 7 is inserted hermetically in the tubular tang 4 and is composed of two portions 7 a and 7 b which are screwed together; said hollow tube forms, together with the hollow stem 6 (i.e., with the sleeves 5 and 5 a ), a tubular interspace 8 . The sleeve 5 b has, at its lower end, a wider portion 9 in which the plate 3 is centered hermetically. The wider portion 9 with the tubular tang 4 forms a chamber 10 that is connected to the interspace 8 through openings 11 of the tang 4 . Furthermore, the chamber 10 is connected to the inside of the hollow tube 7 through openings 12 formed in the region of the tang 4 directly above the plate 3 .
The wider portion 9 forms, together with the sleeve 5 b of the hollow stem 6 , a step 9 a for resting thereon the shoulder 13 b of a tubular element 13 provided with a lower portion 13 a that is shaped so as to have a helical outer slot 14 and recesses 13 c which are distributed peripherally (see FIG. 8 ). As shown more clearly hereinafter, the hollow stem 6 is controlled by actuation elements which, starting from a position in which the step 9 a abuts against the shoulder 13 b , impart thereto a downward stroke, which allows the plate 3 and the wider portion 9 to descend below the portion 13 a . In this manner, the step 9 a abuts against the shoulder 13 b . The portion 13 a and the plate 3 , together with the edge of the cylindrical wider portion 9 in which it is centered, form the forming plug 15 (see FIG. 6) that determines the internal profile of the cap A, i.e., the thread C, the bottom H of the cup B, and the internal protrusions of the tamper-evident band D for retaining the cap on the container to which it is applied. In the illustrated example, said protrusions, in order to match the recesses 13 c , consist of teeth E (see FIG. 8 ), but they can have any shape and in particular they can be constituted by an annular lip.
When the hollow stem 6 is actuated so as to descend, the plate 3 and the cylindrical wider portion 9 protrude from the tubular portion 13 a and, by acting on the bottom H of the cap A, act as an ejector for said cap, hereinafter designated by the reference numerals 3 and 9 .
The upper end of the portion 7 a of the hollow tube 7 is connected hermetically in a seat 16 (see FIG. 2) of the top of the stem 6 , which is in turn inserted hermetically in a seat 17 of a body 18 and is retained by a screw 19 . A connector 20 is arranged on the body 18 , and two holes 21 , 22 are formed therein; said holes are connected to the delivery and to the return of a cooling liquid. The holes 21 , 22 are connected to the hollow tube 7 and the tubular interspace 8 by means of passages 23 , 24 of the body 18 and of the stem 6 , so as to convey the cooling liquid into the chamber 10 and ensure the cooling of the plug 15 and the setting of the plastics of which the cap A is made.
The hollow stem 6 , with its portion 5 a , is guided slidingly in a tubular element or sleeve 25 , which is accommodated coaxially in a cylindrical seat 26 of a supporting body that is part of the structure of the carrousel. In practice, said body is constituted by a sort of rotary drum 27 , which is mounted on a vertical shaft whose axis Z is the rotation axis of the carrousel. The sleeve 25 is suitable, with its lower end, to act as an abutment for the tubular element 13 during the molding of the cap A.
A bush 28 is inserted in the seat 26 and abuts, with an upper annular lip 29 , on the edge of the seat 26 . An external flange 32 of the sleeve 25 rests on the annular lip 29 , with the interposition of a ring of elastic material 30 and of a spacer ring 31 . Retention elements 33 engage on the flange 32 and, by means of screws (not shown in the drawing), lock on the upper face of the drum 27 the sleeve 25 and the bush 28 coaxially to each other and to the seat 26 .
The bush 28 forms, together with the tubular element 23 and the sleeve 25 , a compartment 34 in which there is a tube 35 , which can slide on the tubular element 13 , and there is a bushing 36 , which can slide on the tube 35 . The lower end 35 a of the tube 35 is chamfered externally in a conical fashion.
Axial sliding bearings 37 , 38 are interposed between the tube 35 and the bushing 36 and between said bushing and the bush 28 .
In the compartment 34 , above the bushing 36 , there is a cylindrical case 39 , which rests, with a lower inner lip 40 , on the top of the bushing 36 . A center bearing 41 is centered on the case 39 , and a ring 42 of elastic rubber-like material is interposed between said center bearing and the flange 32 of the sleeve 25 .
The tube 35 has, at the top, an outer lip 43 for abutment on the inner lip 40 of the case 39 , which supports a center bearing 44 for the resting of a cylindrical spring 45 . The spring 45 is accommodated in an annular chamber 45 a comprised between the sleeve 25 and the case 39 and abuts against the center bearing 41 . The compression strokes of the spring 45 , i.e., the upward strokes of the tube 35 , are limited by the abutment of the center bearing 44 against a shoulder 46 of the sleeve 25 .
The tube 35 has, at its lower end, a circular hollow 47 (see FIG. 3) for the vertical retention of four sectors 48 , which are arranged so as to constitute a forming ring for a region of the tamper-evident band D of the plug A and at the same time act as an aid for the ejection of the cap A performed by the plug 15 after molding the plastics and opening the mold.
The sectors 48 cover a 90° angle about the axis X and are provided with collars 49 , which engage in the hollow 47 .
Furthermore, the sectors 48 protrude downward, beyond the lower end of the sleeve 35 , with a conical segment 50 , which ends with an edge 51 that is concentric to the axis B and is provided with a slot 51 a , which faces the portion 13 a of the tubular element 13 . The edge 51 therefore allows to form, on the outside of the cap A, the step G and the collar F, i.e., undercuts which, in conventional molds, contrast the extraction of the molded item.
The ring constituted by the sectors 48 is substantially frustum-shaped, and on the outer surface of each sector there is a dovetail slot 52 , which lies on a radial plane that passes through the axis X. The slots 52 constitute sliding guides for keys 53 , which are fixed in seats 54 of a conical ring 55 that is centered and fixed by means of screws 56 coaxially to the axis X under a plate 57 , which is slidingly guided on the bushing 36 .
The keys 53 diverge downward with the same angle as the slots 52 , so that when the bushing 36 is actuated so as to descend, the sectors 48 move mutually apart in a radial and circumferential direction and remain engaged axially with the hollows 47 by means of the collars 49 .
The plate 57 is rigidly coupled to the rotary drum 27 by means of a pin 58 (see FIGS. 1 and 4 ), which is fixed with one end under said drum and is provided, at its opposite end, with a mushroom-like part 59 . The pin 58 can slide in a hole 60 formed in a wing 61 of the plate 57 , and on the portion of the pin 58 that lies between the wing 60 and the drum 27 there is a spring 62 which, by means of its opposite ends, rests on the wing 61 and on the drum 27 , with bushings 63 and 64 interposed.
The spring 62 keeps the plate 57 rested on the sectors 48 , which accordingly, during the descent of the bushing 36 , remain closed in a ring-like arrangement until the wing 61 abuts against the mushroom-like part 59 of the pin 58 .
When the wing 61 , after performing a stroke “h” from a preset raised position, abuts against the mushroom-like part 59 , by means of the additional stroke of the bushing 36 the sectors 48 are forced, by the engagement of the keys 53 in the slots 52 , to follow a path that diverges downward and causes the edges 51 to be spaced from the lower threaded portion 13 a of the tubular element 13 . In order to actuate the bushing 36 there is a column 65 (see FIG. 2 ), which can slide, by means of bearings 66 and 67 , in a seat 68 of the drum 27 that is parallel to the seat 26 and whose axis is radially internal with respect to the axis X of the unit S.
An arm 69 (see FIGS. 1 and 3) is fixed to the lower end of the column 65 by means of a screw 68 and is provided with an opening 70 , through which the bushing 36 is guided. The opening 70 is shaped so that its edge remains gripped between two collars 71 , 72 of the bushing 36 , so as to provide an axial connection thereof with the column 65 . The sleeve 36 can be positioned at an angle to the arm 69 by means of a pin 73 , which is guided in a radial hole 73 a of the arm 69 and is provided with a knob 74 ; by acting on said knob in contrast with a return spring 75 , it is possible to cause the engagement of the pin 73 in any one of a plurality of holes formed in the sleeve 36 between the collars 71 and 72 .
The column 65 protrudes above the drum 27 with a tang 76 (see FIG. 2 ), which slidingly supports, with the aid of bearings 77 and 78 , a sleeve 79 . The sleeve 79 has a collar, which acts as a shoulder 80 , and is surmounted by a washer 81 that rests on the upper edge of the sleeve 79 . A precompressed spring 82 rests on the washer, and its top end rests against a bushing 83 , which is fixed to the upper end of the tang 76 in an adjustable manner in order to be able to adjust the precompression of said spring 82 .
A ring 84 is screwed onto the sleeve 79 until it abuts against the shoulder 80 , and a stem 85 protrudes from said ring 84 and supports two rollers 86 , 87 . The roller 87 is engaged in a cam 88 , which is rigidly coupled to the fixed structure of the apparatus and is therefore stationary with respect to the drum 27 . The roller 86 is guided in a vertical slot of a bracket (not shown in the drawing), which is fixed on the drum 27 and is meant to prevent the rotation of the sleeve 79 with respect to the tang 76 .
The cam 88 has a circular extension that is concentric with respect to the axis Z of the carrousel, so as to produce axial movements of the column 65 , and, by way of the connection provided by the arm 69 , of the bushing 36 .
The axial movement of the bushing 36 is combined with the movement of the ejector 3 , 9 . For this last movement, there is a roller 89 , which is mounted on the cylindrical body 18 at the top end of the stem 6 and is capable of following an axial cam 90 , which is also stationary and concentric with respect to the cam 88 .
The roller 89 is retained on the profile of the cam 90 by a spring 91 , which rests on the flange 32 in a downward region and on a shoulder 92 of the body 18 , with a cup-shaped washer 93 interposed, in an upper region.
In order to prevent the rotation of the stem 6 and of the body 18 about their own axis, there is a bridge 94 , which is fixed to the top of two columns 95 , 96 and has an opening 97 through which the cylindrical body 18 is slidingly guided.
An axial slot 98 is formed in the outer surface of the cylindrical body 18 , and a key 99 slidingly engages therein; said key is fixed to the bridge 94 and protrudes into the opening 97 , allowing the body 18 to slide, but not rotate, in the opening 97 .
The operation of the described apparatus is as follows. During the rotation of the carrousel, a dose of plastics having a pasty consistency is deposited in the cavity of the female mold part 2 . In this step, the female mold part 2 is lowered with respect to the male mold part 1 , while the plug 15 , by means of the spring 91 , is actuated into the upward stop position determined by the abutment of the step 9 a of the portion 9 against the shoulder 13 b of the tubular element 13 and of the top end thereof against the lower end of the sleeve 25 .
In this stop position, the lower end 35 a of the tube 35 lies above the edges 51 of the sectors 48 , in front of the recesses 13 c of the portion 13 a.
When the female mold part 2 is lifted hydraulically, the edges 51 of the sectors 48 initially abut against the shoulder 100 of the mold part 2 (see FIG. 1) and then against the lower end 35 a of the tube 35 , thus delimiting the cap forming chamber. As the upward motion of the female mold part 2 continues, the plastics is distributed into the forming chamber, filling it and causing, owing to its own incompressibility, the female mold part to stop in the final position, in which the cap A has assumed its final shape.
It should be noted that the spring 45 , by acting on the tube 35 and, by means of the lip 44 of the case 39 , on the bushing 36 , keeps the edges 51 rested on the shoulder 100 and allows to vary the volume of the forming chamber according to the quantitative variations of the dose of plastics that is deposited in the cavity of the female mold part.
When the plastics has reached a suitable setting point, determined by feeding cooling liquid into the chamber 10 and into the similar chamber of the female mold part, so that plastic deformations of the cap are no longer a concern, the descent of the female mold part 2 is actuated. However, the cap A is retained on the plug 15 by the engagement of the thread C in the slot 14 of the portion 13 a and by the retention of the tamper-evident band D between the outer surface composed of the edges 51 of the sectors 48 and the conical end 35 a of the tube 35 and the inner surface, composed of the region of the portion 13 a that is provided with the recesses 13 c.
When the female mold part 2 is spaced sufficiently from the plug 15 , the downward movement of the column 65 and of the hollow stem 6 is actuated by means of the cams 88 and 90 .
The descent of the hollow stem 6 causes (see FIG. 6) the lowering of the plug 15 to the stroke limit level, at which the tamper-evident band D lies below the conical end 35 a of the tube 35 . At the same time, the descent of the column 65 , by means of the arm 69 , determines the descent of the bushing 36 and the downward actuation of the sectors 48 .
The descent stroke of the column 65 comprises a first portion, which is equal to the stroke of the plug 15 , during which the conical ring 55 , by way of the spring 62 that acts on the wing 61 of the plate 57 , remains engaged on the sectors 48 and prevents their opening. During said first portion, the descent of the sectors 48 is accompanied by the descent of the plug 15 and the edges 51 therefore remain in resting contact on the step G of the molded cap A.
At the end of the first portion of the stroke, the wing 61 abuts against the mushroom-like part 59 of the pin 58 , which stops the descent of the plate 57 and of the ring 55 , while the tubular element 13 , by way of the presence of a top collar 13 d (see FIG. 2) that abuts on a shoulder 35 b of the tube 35 , stops with respect to the stem 6 .
In particular, it should be noted that the descent of the tube 35 is prevented by the abutment of the outer lip 43 against the inner lip 40 of the case 39 , which in the meantime, by means of the spring 45 , has moved so as to rest against the internal shoulder 28 a of the bush 28 .
The halting of the tube 35 allows the formation, above the edges 51 , of an annular opening 101 (see FIG. 6 ), into which the tamper-evident band D can expand in order to allow the teeth E to protrude from the respective recesses 13 c of the portion 13 a.
With the second portion of the descent stroke of the column 65 and of the hollow stem 6 (see FIG. 7 ), the thrust applied to the sleeve 36 and to the stem 6 actuates downward the sectors 48 and the ejector 3 , 9 , which by acting respectively on the step G and on the bottom H of the cap A cause the disengagement of the thread C from the slot 14 and of the teeth E from the respective recesses 13 c of the portion 13 a , allowed by the elasticity of the plastics, which allows the cup B to expand radially and allows the tamper-evident band D to open out into the opening 101 .
As they continue their descent, the sectors 48 are forced, by the oblique orientation of the guides 52 and 53 , to move further away from the peripheral region of the cap until they leave the step G. At this point, the complete extraction of the cap A is entrusted solely to the ejector 3 , 9 , whose thrust continues until the teeth E have descended below the lower edge of the portion 13 a , beyond which the cap A can fall freely into a collection area.
It is evident that the fundamental prerogative of the present invention is that the sectors 48 allow to act both as elements for forming undercuts that lie externally with respect to the cap and as elements that assist cap extraction. The thrust applied axially to the cylindrical wall of the cap by the sectors 48 in fact facilitates the widening of the cap that is required in order to allow the ejector 3 , 9 to force the exit of the thread C from the helical slot 14 without causing the material of the cap to yield.
By contrast, it should be noted that in conventional molding units, in which cap extraction is entrusted solely to the ejector, the thrust applied by said ejector to the bottom of the cap causes the cylindrical wall of the cup B to clamp more tightly onto the tubular portion 13 a . This fact obviously requires more force to remove the thread C from the slot, with severe consequences for the integrity of the cap.
The described apparatus is susceptible of numerous variations in order to deal with the different types of product.
FIGS. 9 and 10 are sectional views of the lower part of a unit for the compression molding of the lower part L of a container made of plastics, which is composed of a frustum-shaped plate M and an externally threaded neck N.
In FIGS. 9 and 10, the elements constituting the unit that are identical or equivalent to those of the unit shown in FIGS. 1 to 8 are designated by the same reference numerals.
As clearly shown, the unit of FIGS. 9 and 10 is constructively simpler, owing to the fact that the part L to be molded is not provided with inner undercuts which, in order to be able to disengage from the respective molding recesses of the plug 15 during part extraction, would have to be able to expand outward, as allowed for example by the end 35 a of the tube 35 of the molding unit described earlier. The absence of the inner undercuts therefore allows to remove the part simply by opening the conical segments 51 .
The disclosures in Italian Patent Application No. B02000A000704 from which this application claims priority are incorporated herein by reference. | An apparatus for manufacturing plastics items provided with external undercuts, comprising at least one compression molding unit, which is composed of an upper male mold part comprising a plug and of a lower female mold part aligned, along a vertical axis, with the male mold part, means for actuating the mold parts between a spaced position, at which a dose of plastics sufficient to form an item is deposited in the female mold part, and a mating position for producing the compression molding of an item, the male mold part comprising a plug and an ejector that is associated with the plug in order to remove the molded item when the mold parts are in the spaced position, further comprising a bushing that is arranged externally and coaxially to the plug, a plurality of sectors for forming raised portions and undercuts on the outer surface of the item, the sectors being coupled axially to the bushing and being able to expand with respect to the plug, means for actuating the sectors between a position that produces mating with the plug in order to allow the compression molding of the item and the molding of the raised portions and undercuts, and a spaced position in order to allow to remove the molded item from the plug. | 8 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Reference is made to commonly-assigned copending U.S. patent application Ser. No. 09/672, 245, filed Sep. 28, 2000, entitled MEDIA ADJUSTMENT GUIDES FOR IMAGE FORMING APPARATUS, by Brugger et al.; U.S. patent application Ser. No. 09/734,453, filed Dec. 11, 2000, entitled INTELLIGENT FEEDER, by Brugger et al., the disclosures of which are incorporated herein.
FIELD OF THE INVENTION
[0002] The present invention relates in general to copiers, printers, facsimile apparatus, and scanners, and more particularly to a capacity control system for a paper supply elevator having variable capacity.
BACKGROUND OF THE INVENTION
[0003] In image forming devices, for example, scanners, stack feeding subsystems are often used to feed a plurality of sheets from a stack into a paper transport where they are subsequently imaged by an illumination and imaging means such as CCD and reduction lens. The output of these devices is a digital file format such as TIFF and JPEG images.
[0004] The stack feeding subsystems are often configured with a paper supply elevator subsystem providing the ability to feed stack heights as great as 1,000 sheets of 20 lb. bond paper in sizes up to 11 inches wide×17 inches long. Typically, customers desire to utilize the sheet feeding device in differing sheet capacities, i.e., number of sheets. Depending on the given set or job being imaged, the amount of sheets can vary from as little as one at a time to as many as the maximum capacity or 1,000 sheets or some batch size between one and 1,000 sheets.
[0005] In a typical elevating paper support trays, the tray supports a stack of paper. A tray down or home position sensor indicates when the tray is at its most downward position. In this position the tray is ready to be loaded with a stack of paper. A paper present sensor indicates that paper has been loaded into the tray and begins the tray rise sequence. A “stack up” sensor is employed to indicate when the stack of sheets has been raised to the level where auto feeding can commence. Typically, this is at a point where the stack has been brought into contact with a series of rollers or belts that utilize friction to remove the top or desired sheet from the stack and transport it into downstream rollers or belts that then pass it by the imaging subsystem.
[0006] The inherent drawback in utilizing a 1,000 sheet capacity elevator subsystem to handle all desired batch sizes is that for anything less than the full capacity, the elevator is spending time raising up or lowering. This raising and lowering time can be significant in high speed-high productivity scanners where pages are being scanned at rates of 160 pages-per-minute or greater. Typically, the time required for one of these trays to rise or lower their full range is about four seconds. In addition to the productivity loss, time wasted in waiting for the tray to raise or lower can become a customer annoyance in that many of the subsystems are implemented with motorized drives that can create undesirable acoustic noise.
[0007] In several products, an attempt has been made to deal with this concern by offering the customer a fixed number of intermediate capacities. Generally these intermediate positions offer two or three fixed points that break up the 1,000 sheet capacity (generally 1 to 50, 50 to 250 and 250 to 1,000.) For instance, if the customer typically deals with batch sizes of 250 sheets, they could select a paper support or feed tray intermediate position that is closest to this amount during scanner setup. The feed tray would then limit its downward travel to always stop at a capacity level equal to 250 sheets. These intermediate positions thereby reduce the unwanted time spent waiting for the tray to raise or lower.
[0008] There are two basic drawbacks to the “fixed intermediate position” approaches currently employed. First, the small number of intermediate choices can still leave the customer with a less than optimized tray position for any given job or batch size. Secondly, these implementations achieve these intermediate positions by incorporating additional sensors for the fixed set points. These additional sensors add unnecessary unit manufacturing cost to the product as well as add additional complexity that can reduce overall product reliability.
[0009] A more desirable means of optimizing the productivity of an elevating tray system would allow the customer to set the paper support tray capacity at the exact height or amount that they need to run their batches or jobs. This would eliminate any wasted time in raising the tray up to the “Stack Up” position or lowering it to accept the next batch of sheets.
SUMMARY OF THE INVENTION
[0010] Briefly, according to one aspect of the present invention a capacity control system for a paper supply elevator comprises a paper support and a paper sensor for detecting the presence of paper on the paper support. A home position sensor detects a home position of the paper support. A stack up sensor detects a topmost sheet of paper in a stack of papers located on the paper support. An intermittent drive raises and lowering the paper support. A control panel inputs an expected paper stack size. A control circuit for the intermittent drive causes the intermittent drive to move the paper support to a position corresponding to the expected paper stack size.
[0011] It is an object of the present invention to provide a means for controlling an paper support tray that allows the customer to set any desired intermediate position to maximize productivity and customer satisfaction. This needs to be configured in a manner that it does not require individual tray position sensors to enable all possible “intermediate positions” thereby reducing the product manufacturing cost and increasing the overall system reliability.
[0012] According to one embodiment the invention comprises:
[0013] (a) an elevator tray drive system (stepper motor and lift drive train) raises or lowers a stack support means, tray in small or fine-step increments. Small or fine increments meaning the equivalent of a few sheets of typical paper;
[0014] (b) a home position sensor that indicates when the stack support tray is at its home or maximum capacity position;
[0015] (c) a paper present sensor that indicates when paper is in the stack support tray;
[0016] (d) a tray control capable of controlling the elevator tray drive system so as to elevate or lower the stack support tray in small incremental based on the inputs it receives from the above sensing elements;
[0017] (e) an operator control panel for the customer to input a desired an intermediate position to the control means; and
[0018] (f) the tray control means to control the lifting and lowering of the stack support.
[0019] In another embodiment the operator control panel found on the scanner or from an attached host PC graphical user interface and a SCSI command set. The intermediate position to be selectable from one of many (greater than 50) possible selections, thereby optimizing the ability to match the tray's capacity to the customer job or batch.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] [0020]FIG. 1 shows a side view of the stack support in the home position.
[0021] [0021]FIG. 2 shows a front view of a scanner.
[0022] [0022]FIG. 3 shows a side view of the scanner incorporating the present invention.
[0023] [0023]FIG. 4 shows a detailed view of the home position sensor with a tray flag in the home position.
[0024] [0024]FIG. 5 shows a detailed view of the stack up sensor and the feed module flag with the stack in the stack up position.
[0025] [0025]FIG. 6 shows a detailed view of the paper present sensor.
[0026] [0026]FIG. 7 is a flowchart for control scenario.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Referring to now to FIG. 1 and the flow chart found in FIG. 7, the operation of the invention is as follows. At power on 12 , the machine control logic polls the home or tray down position sensor 14 (see FIGS. 1 and 4) to see if it is blocked or unblocked. The home position 14 sensor is an opto interrupter type and is blocked when a tab on the paper support tray 16 moves into a position known as the home or tray down position 18 . If the paper support tray 16 is determined to be down as indicated by the home position sensor 14 then the operation sequence continues, if not, then the machine logic will issue a set amount of stepper down steps 20 to the stepper motor 22 (see FIG. 1). The stepper motor 22 then drives the paper support tray 16 downward through lift chain 24 , and cable anchor point 26 . A side view showing these drive train elements is found in FIG. 1.
[0028] A complete description of the workings of this drive train system is not included, but this arrangement is typical within the art of elevating high capacity lift trays for autofeeding of sheet media.
[0029] The stepper motor 22 will continue to drive downward until the sensor 14 becomes blocked or a Max Step Count 28 is reached. “The Max Step Count” 28 represents a number of steps that should be able to have driven the paper support tray 16 it's full travel plus a small amount of extra steps. If the “Max Step Count” 28 is reached without blocking the sensor 14 then an error 30 is flagged and reported back to the operator through the operator control panel found in FIG. 2. If the Home Position Sensor 14 is blocked, the process continues.
[0030] Machine logic looks at it's setup tables to see if an “Intermediate Position” 34 has been selected. This intermediate position 34 is set by the customer through a PC attached to the scanner and an appropriate PC to scanner communications (typically SCSI). The Graphical User Interface or GUI would contain a display that would allow the customer to choose an intermediate position that is best suited for the size of batches that the customer wants to feed. This intermediate position 34 can be set with granularity as fine as one stepper motor 22 step. For example, in the implementation described here, each stepper motor 22 steps equates to approximately 3 or 4 sheets of 20 lb. bond paper—(a command to move the stepper motor one full step will result in the paper support tray 16 being lifted or lowered approximately 0.015″ which is the equivalent of about 3 to 4 sheets of paper.) Therefore, a GUI could be designed to allow the customer to break up the full capacity of 1,000 sheets into “Intermediate Positions” 34 separated by 0.015″ or 1,000 sheets divided by 4 sheets per position giving as many as 250 possible intermediate positions 34 choices. This approaches totally variable capacity setting.
[0031] If an intermediate position 34 has not been selected, then the machine logic assumes that the maximum capacity or 1,000 sheets is desired. This 1,000 sheet tray position is equivalent to the paper support tray 16 being all the way down and at the position where the “Home Position” sensor 14 is blocked. At this point in the process, the machine logic checks to see if the stack up sensor 36 is indicating that the feed module 38 has been raised up which in turn unblocks the opto interrupter “Stack Up Sensor” 36 . This is accomplished when the stack of documents 40 comes into contact with the drive tires located within the feed module. See FIG. 5. A solid plastic flag 42 which is part of the feed module housing rotates with the housing until such a point where the flag 42 no longer block the opto interrupter sensor. (this point is known as the “Stack Up Position.”) If the “Stack Up” sensor 36 is blocked, then the machine logic assumes that there is no paper loaded and commands the stepper motor 22 to drive up until the prescribed “Intermediate Position” 44 or number of steps has been met. At this point, the tray has been put in the “Intermediate Position” 44 desired by the customer and will return to this position each time a document stack 40 has been fed from the paper support tray 16 unless the “Intermediate Position” 44 is subsequently changed by the customer or a power down occurs to the scanner.
[0032] By utilizing the number of steps as the means of setting an “Intermediate Position” 44 this allows more customers settable positions and requires no additional hardware or sensors to accomplish this functionality. This reduction in hardware results in manufacturing cost benefits as well as better overall system reliability. Again, as was the case on initial power up, the stepper motor command is bounded by a “Max Step Count” 46 and if this count is reached, the machine logic will flag an error 48 .
[0033] At this point in the process the customer can command the scanner to feed documents by pressing a start scan button 50 on the scanner. (It is also possible to give this command through the host PC and it's SCSI communications interface.) The machine logic receives the start command and polls the “Paper Present Sensor” 52 to determine is paper has been loaded into the paper support tray 16 to be fed. The “Paper Present Sensor” 52 , see FIGS. 2 and 6, is a reflective type sensor located within the paper support tray 16 . If there is no paper present 54 , then no scanning will commence. If paper is present 54 , then the machine logic will check to see if the “Stack Up Sensor” 36 is indicating that the document stack 40 is at the “Stack Up” position 56 or not. The “Stack Up” position 56 where the paper is at the desired elevation for reliable feeding 58 . If the stack up sensor 36 is satisfied then feeding 58 commences. If the stack up sensor 36 is not satisfied then the tray is driven up until it become unblocked and the paper has reached the desired height for reliable feeding and feeding commences. Feeding of the sheets involves engaging an electromechanical clutch that causes the feed module 38 tires to rotate and thereby advance the top sheet into the paper path 60 . This electromechanical clutch is in turn coupled to the scanner's main drive motor and drive system from which it receives it's power. Once a sheet is fed from the paper support tray 16 , it is advanced through the scanner via a series of rollers and belts. At some point in the paper travel, an illumination source and a CCD—Lens Reduction image forming system produces the desired electronic image. The sheet continues through the paper transport and is delivered to an output tray. See FIG. 3 which depicts a side view of a typical image forming paper path.
[0034] At this point in the process, sheets are being fed from the paper support tray 16 and the machine logic monitors the state of the “Stack Up” and paper present sensors 52 . As the sheets feed out from the original “Stack Up” position, the feed module gradually rotates downward until such time that the “Stack Up” sensor 36 becomes blocked again (see FIGS. 1 and 5). The machine logic command the motor to step upward and satisfy the “Stack Up Sensor” 36 . This process continues until all sheets have been successfully fed from the support tray which is then indicated by the “Paper Present Sensor” becoming unblocked at the end of the batch. The tray then returns to the prescribed “Intermediate Position” 34 and is ready to accept the next batch of documents for feeding.
[0035] The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention.
PARTS LIST 12. Power on 14. Home position sensor 16. Paper support tray 18. Home position 20. Stepper down steps 22. Stepper motor 24. Lift chain 26. Cable anchor point 28. Max Step Count 30. Error 32. Operator control panel 34. Intermediate Position 36. Stack up sensor 38. Feed module 40. Document stack 42. Feed module flag 44. Intermediate Position 46. Max Step Count 48. Error 50. Start scan button 52. Paper present sensor 54. Paper present step 56. Stack up position 58. Feeding 60. Paper path 62. Illumination source | A capacity control system for a paper supply elevator comprises a paper support ( 16 ) and a paper sensor ( 52 ) for detecting the presence of paper on the paper support. A home position sensor ( 14 ) detects a home position of the paper support. A stack up sensor ( 36 ) detects a topmost sheet of paper in a stack of papers located on the paper support ( 16 ). An intermittent drive ( 22 ) raises and lowering the paper support ( 16 ). A control panel ( 32 ) inputs an expected paper stack size. A control circuit for the intermittent drive ( 22 ) causes the intermittent drive to move the paper support ( 16 ) to a position corresponding to the expected paper stack size. | 1 |
FIELD OF THE INVENTION
The invention relates to a device for compensating for hydraulic effective pressures in a hydraulic accumulator and a hydraulic actuator of a hydraulic system.
BACKGROUND OF THE INVENTION
In prior art hydraulic systems in which hydraulic actuators are used, for example, for support or lifting systems, hydraulic accumulators as spring or damper elements are hydraulically coupled to the actuator for cushioning or attenuating the movements of components moved by the hydraulic actuator. In some operating situations of such systems, however, an uncushioned, rigid dynamic connection between the actuator and the device actuated thereby is necessary, for example, for a hydraulically actuated boom intended to form a rigid support element, or for a tool to be controlled vibration-free when in use. In view of these requirements, the connection between the pertinent actuator and the hydraulic accumulator must be blocked.
In operation with the spring system blocked, the effective pressure in the hydraulic actuator changes according to the performance to be delivered by it. If at this point the system is transferred from the state of the blocked spring system back into the state with the hydraulic accumulator connected, a difference in the effective pressure between the hydraulic accumulator and the actuator leads to uncontrolled motion at the actuator. This uncontrolled motion poses a hazard to the system and a safety risk for system operators.
SUMMARY OF THE INVENTION
An object of the invention is to provide a device that prevents this safety risk from uncontrolled motion.
This object is basically achieved according to the invention by a pressure compensation device having a valve arrangement that blocks the connection between the hydraulic actuator and the hydraulic accumulator. The valve arrangement has an additional control valve that affects pressure compensation when a predetermined difference of the effective pressures is exceeded. This pressure compensation avoids the risk of uncontrolled motion when the system is transferred from the state of the blocked spring system into the state with the spring system released, because the respective effective pressures of the hydraulic accumulator and of the hydraulic actuator are matched to one another.
If, in the state of the blocked spring system, the pressure that is effective in the hydraulic accumulator is less than the effective pressure in the respective working situation in the hydraulic actuator, pressure compensation can easily take place in the conventional manner by the hydraulic actuator charging the hydraulic accumulator via a non-return valve up to a constant pressure. The non-return valve closes when the pressure is equal.
The particular advantage of the invention is that, when a higher pressure prevails in the hydraulic accumulator, this pressure is reduced by pressure drainage toward the tank side of the hydraulic system.
The valve arrangement can have a directional valve that, in its release state, establishes a direct fluid connection between the hydraulic actuator and the hydraulic accumulator and interrupts this fluid connection in its blocked state. The control valve can be activated depending on the transfer of the directional valve into the blocked state and can contain a drainage valve controllable by a difference of effective pressures that exceeds the preset value into the drainage valve release state in which a drainage path that reduces the pressure difference toward the tank side of the hydraulic system is formed. This arrangement ensures that the equalization of the effective pressures takes place not only by charging of the hydraulic accumulator, but that charging of the hydraulic accumulator can take place only up to a pressure level at which the prescribed pressure difference is not exceeded, because, when this pressure difference is reached, pressure compensation takes place via the drainage valve toward the tank side of the system.
The hydraulic actuator can have at least one lifting cylinder of a machine with a piston side producing the lifting force and with a rod side connected to a control block of the machine. The piston side of the lifting cylinder is connectable via the directional valve to the hydraulic accumulator. The control valve has a connection to the hydraulic accumulator and fluid paths to the piston side and to the rod side of the lifting cylinder. Two fluid paths contain non-return valves that clear the fluid path only to the side of the lifting cylinder carrying the higher effective pressure.
A drainage valve can be in the form of a pressure compensator. In the release state, the pressure compensator clears the drainage path toward the tank side from the connection to the hydraulic accumulator and from the fluid path cleared in each case and leading to the lifting cylinder.
To avoid generating noise or causing damage to the hydraulic accumulator, the drainage process can take place from the accumulator to the tank side only when the pressure difference is somewhat greater than zero. At the same time, preloading that intensifies the action of the closing pressure can be active on the pressure compensator.
The pressure compensator can have a slide valve piston that, for its displacement into the blocking position on one piston area, can be loaded both with the closing pressure from the hydraulic working circuit and loaded with the force of a preload spring.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings which form a part of this disclosure:
FIG. 1 is a schematically simplified, side elevational view of a mobile machine in the form of a wheel loader, equipped with one exemplary embodiment of the device according to the invention;
FIG. 2 is a symbolic circuit diagram of the hydraulic system of the exemplary embodiment of the device according to the invention, shown in the operating state with the spring system released;
FIG. 3 is a circuit diagram of the device of FIG. 2 , with the operating state being shown with an effective pressure in the hydraulic accumulator that is smaller than the effective pressure on the piston side of the lifting cylinder;
FIG. 4 is a circuit diagram of the device of FIG. 2 , with the effective pressure in the accumulator being greater than on the piston side of the lifting cylinder;
FIG. 5 is a circuit diagram of the device of FIG. 2 with the effective pressure on the rod side of the lifting cylinder being greater than on the piston side or in the hydraulic accumulator;
FIG. 6 is a functional and schematic side elevational view of a pressure compensator that serves as a drainage valve of the exemplary embodiment of FIG. 2 ;
FIG. 7 is a symbolic representation of the pressure compensator of FIG. 6 ; and
FIG. 8 is a side elevational view in section of a spool valve that serves as a pressure compensator of FIG. 6 and that can be inserted into a valve block (not shown).
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a mobile machine in the form of a wheel loader 1 with a shovel 3 coupled to a lifting cylinder 5 . The cylinder 5 forms the hydraulic actuator of the exemplary embodiment of the device according to the invention to be described. The piston side 7 of the lifting cylinder 5 produces the lifting force for the shovel 3 when pressure is supplied and is connected to a hydraulic accumulator 9 , indicated only symbolically in FIG. 1 , via the hydraulic components not illustrated in FIG. 1 .
FIGS. 2 to 5 in a symbolic representation show the circuit of the hydraulic system in different operating states. FIG. 2 shows the state with the spring system released. A control block 13 of the machine (wheel loader 1 ) with a pressure supply (not shown), for controlled supply of the lifting cylinder 5 is connected to its piston side 7 and its rod side 15 . A valve arrangement 11 that forms the principal part of the hydraulic system has inputs or ports 17 and 19 connected to the piston side 7 and the rod side 15 of the lifting cylinder 5 , respectively. The hydraulic accumulator 9 and the tank 25 of the hydraulic system are connected to the outputs 21 and 23 , respectively, of the valve arrangement 11 .
As mentioned, FIG. 2 shows the state of the released spring system. A directional valve 27 is in its release state as a result of its mechanical spring preload or spring 29 . The piston side 7 on the input or port 17 is connected directly to the hydraulic accumulator 9 at the output 21 , and the rod side 15 of the lifting cylinder 5 is connected via the input 19 directly to the tank 25 at the output 23 . In this operating state, the other hydraulic components are not involved in the operating process; i.e., the system effects a conventional cushioning/damping of the activity of the lifting cylinder 5 .
As mentioned, in certain operating situations a spring system is not useful or is detrimental. When a shovel 3 of a loader 1 is actuated, for example, spring compression or rebound has a negative effect on the accuracy of the positioning of the shovel 3 . The system is transferred into the state of the blocked spring system such that, by supplying a hydraulic control pressure via a control line 50 , the directional valve 27 is moved into the blocking state against the preload 29 , as detailed below.
FIGS. 3 to 5 illustrate three different operating modes for the spring system blocked in each case. In FIG. 3 state, the piston side 7 of the lifting cylinder 5 is at a higher effective pressure than in the hydraulic accumulator 9 , as dictated by operation. Accordingly. FIG. 3 shows with the thicker line the fluid connections that carry the higher pressure, specifically from the input 17 of the valve arrangement 11 to the blocked directional valve 27 via a line branch 31 and from the line branch 31 via a closing pressure control line 33 shown by the thick line to a control port 35 of a drainage valve 37 . This control port 35 is designated as the second control port. Corresponding to the effective pressure that prevails in the line branch 31 and that is higher than that in the line branch 39 indicated by the thin line at the input 19 and on the rod side 15 of the lifting cylinder 5 , a non-return valve 41 connected to the line branch 31 is opened so that the accumulator 9 at the output 21 is charged to the pressure of the piston side 7 via an accumulator line 43 . In this state, the non-return valve 45 , connected between the accumulator line 43 and input 19 in the same direction as non-return valve 41 , is closed. This arrangement of the non-return valves 41 and 45 causes the higher effective pressure from the inputs 17 and 19 to take effect in the system via a respective fluid path formed by opening of one or another non-return valve. Furthermore, in the connecting line to the accumulator 9 between the two port sites of the non-return valves 41 and 45 another non-return valve 46 is connected that, oriented toward the accumulator 9 , moves into its pertinent closed position.
Another control port 47 of the drainage valve 37 , referred to as the first control port, is connected via a control valve 49 , when it is in its opening state shown in FIG. 3 , to the accumulator line 43 which in turn is connected to the input 17 or the input 19 corresponding to one or another fluid path, i.e., depending on which of the non-return valves 41 or 45 is opened. In the state shown in FIG. 3 , the fluid path leads via the non-return valve 41 to the input 17 that carries the higher effective pressure. The pressure that prevails on the first control port 47 via the opened control valve 49 also serves as a hydraulic control pressure that hydraulically transfers the directional valve 27 , which directional control valve 27 is preloaded into the opening state by its spring preload 29 , into the closed state shown in FIG. 3 , and thus, moves the entire system into the state of the blocked spring system.
With the released spring system in the state of FIG. 2 , the control valve 49 is in its closed state caused by its actuating magnet 51 being energized so that the valve 49 is closed against its opening spring 52 . In this way, in the state of the released spring system, the first control port 47 of the drainage valve 37 and the control line 50 of the directional valve 27 are depressurized by connecting to the tank side 25 . The preload 29 therefore keeps the directional valve 27 in its opening state. If the power to the actuating magnet 51 is interrupted and the control valve 49 is opened, the directional valve 27 is hydraulically directed against its preload 29 into the blocked state via the control line 50 , and the system passes into the state of the blocked spring system, as is shown in FIGS. 3 to 5 .
In the state shown in FIG. 3 , in which the higher effective pressure prevailing in the line branch 31 charges the hydraulic accumulator 9 via the non-return valve 41 and the accumulator line 43 , on the first control port 47 and on the second control port 35 of the drainage valve 37 the same pressures prevail in each case, specifically via the control line 33 from the input 17 and via the opened non-return valve 41 and the opened control valve 49 likewise from the input 17 . The drainage valve 37 is a pressure compensator that is in the closed state when this constant pressure prevails on the control ports 47 and 35 . The drainage valve 47 in this closed state does not form a drainage path from the input port 53 to an output port 55 that leads via a drain line 57 by way of the output 23 to the tank 25 . Therefore, no drainage process takes place from the accumulator line 43 connected to the output 23 and the tank 25 via a pressure limitation valve 59 that forms an overpressure safeguard. A drainage valve 61 is likewise connected to the accumulator line 43 and that is manually opened only for maintenance purposes.
FIG. 4 conversely shows a state in which, likewise with the spring system blocked, the effective pressure in the hydraulic accumulator 9 is higher than the system pressure that is effective as dictated by operation on the piston side 7 of the lifting cylinder 5 , and thus, via the input 17 in the valve arrangement 11 . To illustrate this in FIG. 4 , in the part uppermost in the figure, the accumulator line 43 is indicated by the thick solid line and in its lower line part by the thick broken line. The non-return valve 41 is closed corresponding to the effective pressure that prevails in the hydraulic accumulator 9 , which effective pressure is higher than in the lifting cylinder 5 .
The higher effective pressure of the hydraulic accumulator 9 is on the first control port 47 of the drainage valve 37 via the control valve 49 that is opened by the spring preload 52 and that is not energized. The second control port 35 carries the lower effective pressure of the input 17 via the line branch 31 .
As already mentioned, the drainage valve 37 has a pressure compensator shown symbolically in FIG. 7 and in the form of an operating diagram in FIG. 6 . FIG. 8 shows a longitudinal section of one practical embodiment. Drainage valve 37 is a spool valve with slide valve piston 65 axially displaceable in the valve housing 63 , shown in the closed position. This closing is caused by a hydraulic closing pressure that acts on the second control port 35 , amplified by a mechanical preload force 67 in FIGS. 6 and 7 . The drainage valve 37 opens by a hydraulic opening pressure that is active on the first control port 47 , assuming that the opening pressure on the slide valve piston 65 causes a higher opening pressure than the closing pressure that prevails on the control port 35 , amplified by the preload force 67 . In other words, the condition for the drainage valve 37 to open to form a drainage path from the input port 53 to the output port 55 and thus to the tank 25 is when the closing forces acting on the slide valve piston 65 resulting from the pressure on the second control port 35 , plus the mechanical preload 67 , is smaller than the opening pressure produced by the hydraulic pressure on the first control port 47 . Therefore
F preload +F pressure35 <F pressure47
In the state depicted in FIG. 4 , the pressure from the hydraulic accumulator 9 is drained until only a given, desired low pressure excess between the accumulator 9 and thus the input port 53 remains relative to the control port 35 , i.e., the lifting cylinder 5 , corresponding to the design of the pressure compensator that forms the drainage valve 37 , specifically the effective piston areas and the effective preload force 67 . This state means that a drain process cannot lead to reducing the pressure in the hydraulic accumulator 9 to a value of zero.
Advantageously, the opening pressure difference dictated by the piston geometry and the preload force 67 can be a pressure level of approximately 8 bar. FIG. 8 shows two helical springs 69 and 71 acting on a two-part slide valve piston 65 for producing the preload force 67 and preloading the piston 65 into the illustrated closing position to the right in the figure, in which the input port 53 located on the axial end of the spool housing 53 on the right side in the figure is blocked relative to the output port 55 . In addition to the preload force 67 , the hydraulic pressure from the second control port 35 acts on the side of the piston 65 , which side is the left one in the figure. As the opening pressure for moving the piston 65 in the figure to the left, the right piston area is subjected to the opening pressure via the first control port 47 .
To ensure that the pressure present on the input port 53 does not take effect as the effective control pressure that determines the behavior of the pressure compensator, the piston area 73 indicated in FIG. 6 and bordered by the control edges 75 and 77 between the ports 53 and 55 importantly be considerably smaller than the effective piston areas 79 , 79 a , and 81 on the pressure spaces on the control port 47 or control port 35 .
FIG. 5 relates to another state in which, at the input 19 of the valve arrangement 11 , the higher effective pressure prevails, compared to the pressure at the input 17 or the pressure in the hydraulic accumulator 9 . This operating state arises when a device runs up against an obstacle during operation of a machine with the spring system blocked. This state can be the case, for example, when a mobile device, such as a wheel loader 1 , with its shovel 3 runs up against an obstacle that forms an elevation. As a result of this situation, the weight of the wheel loader 1 resting on the shovel 3 pushes the piston of the pertinent lifting cylinder 5 into the rod side 15 , causing an overpressure to form on the rod side 15 . This overpressure takes effect via the input 19 , with the non-return valve 45 opening in this state, as well as via the opened control valve 49 on the first control port 47 of the drainage valve 37 . When the opening condition is met, i.e., a higher pressure on the port 53 compared to the control port 35 connected to the input 17 via the line branch 31 , the drainage valve 37 then opens. As a result of valve 37 opening, in turn the drainage path to the tank 25 is opened, causing the pressure of the accumulator line 43 to be relieved. The higher pressure in the control port 47 ensures that the valve 37 is not in the blocking position.
As FIGS. 6 and 8 show in particular, the actual pressure compensator is formed by the helical spring 69 and by the effective pressure surfaces of the axially displaceable slide valve piston 65 . The blocking piston made as a valve spool is in turn formed by the helical spring 71 and the effective piston area 81 of the indicated blocking piston part.
The piston 65 in FIG. 6 can be made in several parts to form a non-return valve, i.e., the multipart design prevents opening of the valve seat 55 and unwanted backflow of the fluid into the system when a pressure prevails on the port 55 that is higher than that pressure formed by the preload forces of the helical springs 69 and 71 plus the effective compressive force by the pressure on the second control port 35 . If this non-return valve function is to be omitted, the illustrated slide valve piston arrangement can also be made in one piece (not shown).
The invention thus ensures that the safety function is pressure compensation for all operating modes. The construction of the drainage valve 37 as shown in FIGS. 6 and 8 is not mandatory. Any valve construction whose operation corresponds to the aforementioned opening and closing conditions can be used. The construction of the two-part slide valve piston 65 depicted in FIG. 8 and the construction of the piston part to the right in this figure at the input port 53 forming a non-return valve loaded by the spring 69 with low closing force are not mandatory. In this construction, the closing spring 71 forms the principal part of the preload 67 in FIGS. 6 and 7 and amplifies the closing force of the valve. | A device for compensating for hydraulic effective pressures in a hydraulic accumulator ( 9 ) and a hydraulic actuator ( 5 ) of a hydraulic system ( 11, 13 ) has a valve arrangement ( 27 ) for blocking a connection between the hydraulic actuator ( 5 ) and hydraulic accumulator ( 9 ) and has a control valve device ( 11 ) performing a pressure compensation when a predetermined difference in effective pressures is exceeded. | 5 |
BACKGROUND
[0001] 1. The Field of the Invention
[0002] This invention relates to equipment for trucks and, more particularly, to novel systems and methods for providing adjustable axles for trucks.
[0003] 2. The Background Art
[0004] Highway construction and maintenance is a matter of substantial concern to local, state, and federal governments. Road construction has always been an expensive proposition. Roads constructed using modern knowledge, methods, and technology have greatly improved the load-bearing capacity of vehicles traveling over those roads.
[0005] Specific limitations exist on loading of vehicle axles. It is well established that bridges are designed to carry specific weights. However, in actual bridge design, several additional, localized factors exist. For example, bridges may have one or more surfacing materials, such as concrete or asphalt. The surfacing materials may be designed in various compositions to support various loads and provide predictable durability. However, underlying a bridge or road surface is a structure of specific members each designed for supporting a particular maximum force or load.
[0006] Bridges in various parts of a roadway system have varying weight-carrying capacities. A truck having weight over some number of axles, must also have those axles distributed across a suitable length of the bridge in order to distribute the load of the truck properly over the individual structural members of the bridge.
[0007] Thinking in terms of a truck, not as a truck, but as a series of axles, each bearing a load, one sees another important factor in the mutual design criteria between vehicles and roadways (e.g. bridges). That is, axles cannot be separated from the truck. The truck has a length; therefore, axles cannot be completely separated from each other. Therefore, all of the axles of the truck will pass over the bridge together. The truck has to distribute axles over some maximum length.
[0008] Moreover, the construction of all bridges, streets, highways and roads provides for specific limitations on sustainable loads and the like. For example, just as building construction must start far below the surface level of the earth to support a foundation, many road beds must be deeply laid to provide acceptable sustainable loads. Above a road bed are laid various types and grades of materials. Ultimately, a surface material is provided on which vehicles roll directly.
[0009] Pneumatic tires, in addition to improving a vehicle's ability to absorb shocks from the roughness of a surface, distribute the load of the vehicle over a surface area of a road surfacing material. Tire pressures relate directly to the distortion of a tire in order to present a certain amount of area onto a road for supporting the weight of the vehicle. For example, a four thousand pound vehicle having a total of fifty square inches of tire surface to the road must have a tire pressure of approximately twenty pounds per square inch to support the load. To support the same load or weight of a vehicle at forty pounds per square inch only twenty-five square inches of tire tread must be in contact with the road. Thus, local pressure on a road surface may be controlled, to a certain extent, by the inherit limits on tire pressures.
[0010] The distance between a vehicle's axles is another factor in load distribution on a road bed. For example, two axles spaced relatively closely together will produce more load in a road bed than the same two axles, carrying the same loads, but spaced further apart. Thus, axle location may be very important in determining the local force presented on a bridge or a road bed by a particular axle. In this context, an axle may be used to refer to the axle itself, or to the axle and tires as they represent force application to a road bed from a vehicle supported thereby.
[0011] The regulated carrier industry includes many types and classes of trucks. Trucks require both operable hardware and regulatory compliance. Trucks must comply with weight and dimensional limits for roads and especially bridges. Meanwhile, unnecessary wear is avoidable if unused portions, such as unneeded auxiliary axles, of a truck may be disengaged. For example, the basic structure of a truck includes a steering axle and a drive axle mounted to a frame supporting a cab and a bed. Drive wheels may be arranged as duals, tandems, or dual tandems.
[0012] In certain circumstances, auxiliary axles may benefit a truck. Auxiliary axles provide load-bearing capacity that may be installed to operate permanently or selectively. Auxiliary axles may be positioned to lead the drive wheels, follow the drive wheels, or trail the entire vehicle. Often the requirement to selectively distribute the load on road beds and bridges drives the positioning of auxiliary axles. Suspension systems may vary depending upon the mounting arrangement of any axle on a truck. Moreover, axles that must be engageable selectively may require their own particular adaptations to meet with the manufacturer's specifications for the frame of the truck.
[0013] Trucks today may be manufactured to have tandem axles spaced a comparatively long distance apart, as compared with trucks of previous years. Also, many trucks now carry auxiliary axles that can be engaged for distributing a load along a different length of the truck. For example, long truck bodies or trailers may have wheels located nearer the front end, rather than leaving the entire weight distributed between a front axle and a rear axle or between a tractor and a pair of closely spaced tandem axles at the rear.
[0014] Auxiliary axles are often added to concrete mixer trucks to accommodate limitations on bridge weights. Also, auxiliary axles may be added to accommodate the large differential load between an empty truck and a loaded truck. Thus, auxiliary axles may be engaged for a limited time, only while a vehicle is loaded and is traveling on a road. At a work site, a truck may not need auxiliary axles as a support for the vehicle itself, and may disengage them.
[0015] Thus, heavily loaded trucks having changes in load actually applied thereto, may need auxiliary axles. Those axles need to be distributed along a maximum length, and may need to be distributed along the vehicle itself. To protect roadways, to satisfy bridge weight limitations, and to support substantial loads, auxiliary axles may be used in vehicle construction.
[0016] Truck manufacturers may regard axles of all types as materials. That is, a truck manufacturer may simply purchase axles from a suitable, available supplier. A truck design may be built to accommodate the particular dimensions of a preferred or suitable axle available from a known manufacturer. Not every truck is, however, custom designed. Often, a manufacturer or purchaser of a truck may desire to install a nonstandard axle, such as an auxiliary axle, in order to satisfy a particular need of a particular customer. The customer's needs may be driven by the task to be performed by the truck and the specific limitations on loading of axles applicable to the geographic region in which the truck will be operated.
[0017] Inventory is a perennial problem for manufacturers. If a manufacturer produces a comparatively broad range of designs of trucks, a correspondingly broad range of axle designs may be required. Many designs are sensitive to axle height, as compared to truck frame height. The required suspension system mounting the axle assembly to a truck frame must also be taken into consideration.
[0018] Accordingly, it would be an advance in the art to reduce inventories and design commitments by providing both principal and auxiliary axles adaptable to fit a plurality of vehicle heights. Moreover, it would be an advance in the art to provide an axle assembly that could be inventoried for a truck design, the corresponding frame height thereof, and the particular suspension desired, before all decisions concerning the dimensions of the suspension system and the truck frame height have been determined.
[0019] Thus, an axle design that provides an adjustable, relative height between the center line of the associated wheels and the mounting surface of the axle with respect to a suspension system, would reduce inventory, reduce cost, and provide design flexibility. Design flexibility can be very important, since the more factors that may be determined at a later time, the more custom performance may be provided. That is, intransigent requirements driven by an inflexible design parameter associated with a particular component of a vehicle may drive costs upward for other features of the vehicle. Moreover, incompatibilities between components require specialized combinations that must be designed, documented, maintained, and so forth in order to support a production line thereof.
BRIEF SUMMARY AND OBJECTS OF THE INVENTION
[0020] In view of the foregoing, it is a primary object of the present invention to provide adjustable height for auxiliary axles, and principal axles of a truck. It is contemplated that an apparatus and method in accordance with the invention may provide any principal axle (steering axle, drive axle) or auxiliary axle (leading axle, following axle, trailing axle) with a suitable range of adjustment for the relative height between the top mounting surface of the axle and the centerline of the associated wheels installed thereon.
[0021] Consistent with the foregoing objects, and in accordance with the invention as embodied and broadly described herein, a method and apparatus are disclosed in one embodiment of the present invention as including an axle structure provided with a bracket for securing a mount thereto. Apertures in the bracket and mount may be positioned to match at a plurality of positions. Thus, fasteners may secure the mount to the bracket on each end of the axle at multiple relative positions therebetween.
[0022] A standoff may be provided with the mount, for spacing a wheel assembly a distance away from the end bracket of the axle. Various sizes of tires and wheels may be accommodated by the adjustability between the mount and the bracket of the axle.
[0023] The axle may mount to a frame of a vehicle by various mechanisms. A conventional suspension system may secure the axle to the vehicle frame, or a “pusher” assembly for selectively engaging the axle may be relied upon. In certain embodiments, a swing arm may mount a trailing axle to a vehicle.
[0024] The axle may be formed as a beam of any suitable configuration, including an I-beam, a channel, a box beam, a right circular cylindrical tube, or the like, as a like. Various struts, gussets, fasteners, and the like may secure the brackets to the axle, and the mounts to their respective standoffs for supporting the axle on a vehicle, and the wheels with respect to the axle, respectively. In one embodiment, the mounting hardware for connecting an axle to a vehicle may be integral to the axle. In an alternative embodiment, the axle may be integrally constructed with the suspension system to further reduce weight. Accordingly, the adjustable standoffs for the wheel assemblies may be adjusted to fit the vehicle supported by the apparatus.
[0025] Wheel assemblies may be connected to the mount associated with an axle by means of kingpins, axles, drive axles, fixed spindles, or the like. Thus, a wheel assembly may serve as a driver, a steering assembly, or an auxiliary assembly. Also, a wheel assembly may function as a caster on a kingpin connected to a mount and bracket associated with an axle.
[0026] In certain embodiments, tie rods may connect wheels that caster or turn, and may connect to dampers (hydraulic or pneumatic buffers) for reducing oscillations.
[0027] Universal joints may connect drive axles to axle stubs or spindles driving wheel assemblies. Accordingly, a differential may be provided within an axle in accordance with the invention, having drive axles contain therein for driving connected wheel assemblies. Thus, an axle assembly in accordance with the invention may serve as a principal steering axle of a vehicle, a drive axle of the vehicle, an auxiliary leading or following axle or as a trailing axle, having castered or noncastered wheels mounted thereto.
[0028] The standoff assembly may be straight, angled, offset (vertically or horizontally), shimmed (vertically or horizontally), hollow, filled, or the like, in accordance with the desired functionality for the wheel assemblies connected to the axle. Thus, a standoff may position a drive wheel a distance away from a bracket of an axle, both horizontally and vertically, in order to accommodate vehicle size, axle size, suspension dimensions, and any requirement for mobility (e.g. U joints and drive-ins).
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The foregoing and other objects and features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:
[0030] [0030]FIG. 1 is a rear quarter perspective view of an axle assembly attached to a frame of a vehicle, in accordance with the invention;
[0031] [0031]FIG. 2 is a rear quarter perspective view of the axle assembly of the apparatus of FIG. 1;
[0032] [0032]FIG. 3 is rear quarter perspective view of the apparatus of FIGS. 1 - 2 having one wheel assembly and king pin removed for clarity;
[0033] [0033]FIG. 4 is a top plan view of the axle assembly of FIGS. 1 - 3 ;
[0034] [0034]FIG. 5 is a front elevation view of the apparatus of FIGS. 1 - 4 ;
[0035] [0035]FIG. 6 is a side elevation view of a truck having six axles, any one of which may be an axle in accordance with the invention singly or in any combination;
[0036] [0036]FIG. 7 is a rear quarter perspective view showing a portion of a standoff in phantom in order to demonstrate an optional drive linkage for driving a wheel assembly supported by an axle in accordance with the invention;
[0037] [0037]FIG. 8 is a front elevation view of an alternative embodiment of a standoff in accordance with the invention; and
[0038] [0038]FIG. 9 is a front elevation view of a horizontally shimmed apparatus in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in FIGS. 1 through 9, is not intended to limit the scope of the invention, as claimed, but is merely representative of the presently preferred embodiments of the invention.
[0040] The presently preferred embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. FIGS. 1 - 9 illustrate certain presently preferred embodiments of apparatus and methods in accordance with the invention. Those of ordinary skill in the art will, of course, appreciate that various modifications to the detailed schematic diagrams may easily be made without departing from the essential characteristics of the invention, as described. Thus, the following description of the Figures is intended only by way of example, and simply illustrates certain presently preferred embodiments of the invention as claimed herein.
[0041] Referring to FIGS. 1 - 9 , generally, and specifically to FIGS. 1 - 5 , an apparatus 10 may be configured as an axle assembly or an auxiliary axle assembly. That is, vehicles require wheels. Wheels require axles. Axles are mounted to vehicles by suspension systems. Principal axles include at least one drive axle and a steering axle. The steering axle supports rotating steering wheels and tires. The drive axle supports rotating drive wheels and tires. In accordance with certain embodiments of an apparatus and method in accordance with the invention, an apparatus 10 may provide an axle 12 provided with a bracket 14 attached to first and second ends 13 a , 13 b , respectively.
[0042] Each bracket 14 may be configured to be flat, curved, uniquely shaped, or the like, in order to receive a mount 16 . In one embodiment a bracket 14 may be penetrated by several apertures 15 . The apertures 15 may be aligned in one or more rows suitable for substitution one for another in receiving a fastener.
[0043] Similarly, the mount 16 may be provided with several apertures 17 aligned in one or more rows. The apertures 17 may be matched to the apertures 15 , for positioning the mount 16 at one of several suitable attachable positions with respect to the bracket 14 .
[0044] In practice, the apparatus 10 has corresponding operational directions that may be referred to for convenience, as a longitudinal direction 11 a , a transverse direction 11 b , and a lateral direction 11 c . The longitudinal direction 11 a does not refer to the length of the axle 12 , but rather a longitudinal direction corresponding to forward and backward with respect to a vehicle to which the axle 12 and the apparatus 10 may be secured.
[0045] In some selected embodiments, the apertures 15 , 17 may be arranged in rows extending along a transverse direction 11 b . Accordingly, the apertures 15 may be matched with selected apertures 17 for securement of the mount 16 to the bracket 14 at a selected position. The bracket 14 and the mount 16 need not be of the same dimension in a transverse direction 11 b . For example, in order to provide a larger number of apertures 15 , 17 that may be matched, while providing a greater bearing length of engagement between the bracket 14 and mount 16 , the transverse direction 11 b of either the bracket 14 , or the mount 16 , may be longer than the other.
[0046] A standoff 18 may extend in any direction 11 a , 11 b , 11 c suitable for positioning a wheel assembly 20 with respect to the axle 12 . In certain embodiments, a wheel assembly 20 may be mounted to pivot from a location some substantial distance from a centerline 19 of the axle 12 . In certain embodiments, one may think of the longitudinal direction 11 a as corresponding to the forward and backward, nominal horizontal, direction, the transverse direction 11 b corresponding to the nominal vertical direction, and the lateral direction 11 c corresponding to a side-to-side horizontal direction. Nevertheless, all naming conventions for the directions 11 a , 11 b , 11 c are merely for convenience and reflect no absolute orientation in space being required necessarily.
[0047] Thus, a standoff 18 may typically position a wheel assembly 20 above a centerline 19 of an axle 12 , in order to provide a maximum clearance 21 between the axle 12 , and the frame 30 of a vehicle.
[0048] Likewise, the size of a tire 22 and wheel 24 rotating about the mount 16 , compared with a desired ground clearance 23 between a mounting position 25 of the axle 12 , and a surface on which the tire 22 of the wheel assembly 20 rolls.
[0049] A framing member or beam 26 (e.g. cross beam 26 ) may support a mount 28 for the axle 12 . The beam 26 may be a part of the frame 30 of a vehicle. Nevertheless, the overall clearance 21 , 23 may be accommodated by adjusting the mounts 16 in a transverse direction 11 b with respect to the brackets 14 . The clearance 21 provides for a suspension system 29 , such as an air bag 29 or other load bearing mechanism 29 , that may be used to support the vehicle frame 30 above and against the axle 12 . In the case of the embodiment illustrated in FIG. 1, the axle 12 is a trailing axle 12 . Nevertheless, in other embodiments, the axle 12 may be mounted directly below the frame 30 of a vehicle, in order to provide either principal axle functions, or auxiliary axle functions.
[0050] In a trailing axle configuration, brackets 32 may mount to structures that may or may not be part of the organic frame 30 of a vehicle. In the illustrated embodiment, the brackets 32 include an L-shape for fitting the vehicle frame 30 directly. The brackets 32 , pivotably mounting the axle 12 to the frame 30 , correspond to rear brackets 33 secured directly to the axle 12 . Pins 34 , 35 support pivoting or limited rotation by the arms 36 , 37 with respect to the frame 30 , as well as with respect to the axle 12 .
[0051] In certain embodiments, the pins 34 , 35 may be inserted through journals 38 , 39 or bushings 38 , 39 adding additional bearing surface area against the pins 34 , 35 , above the structural requirements dictating the materials and thicknesses of the arms 36 , 37 . Thus, although the structural requirement for the arms 36 , 37 may require only a comparatively thin wall, the pressure stresses from bearing the load supporting the frame 30 by the axle 12 , may urge the benefit of journals 38 , 39 on a designer.
[0052] Thus, the brackets 32 , 33 and, together with the pins 34 , 35 and the journals 38 , 39 form a pivot assembly 40 . In one embodiment, the arms 36 , 37 may be included as part of the pivot assembly 40 . Thus, a pivot assembly 40 provides for a substantially constant orientation in a circumferential direction 13 of the axle 12 , while providing substantial freedom to move in a transverse direction 11 b.
[0053] Meanwhile, the overall swing arm assembly 42 certainly includes in its structure the brackets 32 , 33 , the pins 34 , 35 , or their equivalents, the arms 36 , 37 , and the journals 38 , 39 . Pivot assemblies 40 resist any translation in a lateral direction 11 c by the axle 12 with respect to the frame 30 , and permit only a certain, limited, arcuate motion, contributing to the movement of the axle 12 in a longitudinal direction 11 a with respect to the frame 30 . Thus, the axle 12 is supported to move in substantially a single direction 11 b in response to roughness of a road, and the absorption of shocks associated with displacement of the axle 12 with respect to a road surface, and a vehicle frame 30 .
[0054] In certain embodiments, the axle 12 may be formed to have a beam 44 . The beam 44 may be configured as an I-beam, a channel beam (C-beam), and H-beam, a right circular, cylindrical, tubular beam, or a rectangular beam of some suitable cross-section. The beam 44 supports primarily a bending load due to support of the vehicle frame 30 by the axle 12 , through the suspension system 42 , a swing arm suspension system 42 , in the embodiment illustrated in FIG. 1.
[0055] In certain embodiments a strut 46 or gusset 46 may secure a bracket 14 to the axle 12 in order to support offset. For example, in certain embodiments a road axle 12 , is desirable. Nevertheless, in many commercial vehicles, a comparatively large-diameter, off-road tire 22 is desirable. To reconcile these two issues, the axle 12 may be dropped with respect to a center line 45 of a tire 22 and a wheel 24 . Thus, a bracket 14 may extend a substantial distance in a transverse direction 11 b above the axle 12 . Accordingly, a strut 46 of suitable structural materials and directions, may strengthen attachment of the bracket 14 to the axle 12 . Likewise, for suitably fitting a vehicle to a tire stance, an offset may be desirable in a transverse direction 11 b , lateral direction 11 c , or both. As illustrated and explained hereafter, the apparatus 10 is adaptable to such variations due to its modular nature.
[0056] The bracket 14 may be secured to the mount 16 and vice versa, by fasteners 48 . The fasteners 48 may be removable or permanent. For example, permanent fasteners 48 may include rivets, welds, or other specialized fasteners. By contrast, removable fasteners 48 , or selectively removable fasteners 48 may include bolts, clamps, and the like. Typically, the threaded fasteners 48 such as the bolt 49 and the corresponding nut 47 may be readily and selectively secured and removed from the bracket 42 and mount 16 . A selective number of fasteners 48 may be required. Similarly, a certain number of apertures 15 , 17 may be required to be engaged with one another, in order to provide sufficient bearing distance to support bending loads exerted by the wheel assembly 20 and standoff 18 , through the mount 16 , against the fasteners 48 connecting to the bracket 14 . Thus, to prevent bending of the bracket 14 or mount 16 , in service, a sufficient bearing distance may be specified, and only a limited number of fasteners 48 may be removed. Likewise, a limited number of apertures 15 , 17 may be required to be engaged, or permitted to be unused.
[0057] In certain embodiments, the wheel assemblies 20 secured to each end 13 a , 13 b of the axle 12 may be configured to function as casters with respect to the axle 12 . A tie rod 50 may connect the wheel assemblies 20 for cooperative tracking. In certain embodiments, to provide greater stability in dynamic environments, bolts 52 and brackets 54 , or the like, may secure a damper 60 to the tie rod 50 . A damper 60 may resist relative motion between an actuator 61 secured to the tie rod 50 , and a mounting bracket 62 of the damper 60 secured to the axle 12 . Thus a damper may resist motion of the tie rods 50 in a lateral direction 11 c , damping against chatter Damper types may include a dashpot, viscous drag system, hydraulic cylinder, brake, buffer, or the like. A damper 60 may be hydraulic, pneumatic, or a combination device. Damping may be comparatively strong, comparatively weak, or non-existent. Nevertheless, damping has been found effective in reducing chatter of castered wheel assemblies 20 in actual operation.
[0058] The tie rod assembly 50 may be secured to the wheel assemblies 20 by knuckles 56 and arms 58 . The arm 58 may serve as a lever in order for the tie rods 50 to pivot each wheel assembly 20 about an axis extending in substantially a transverse direction 11 b . Actually, an axis of rotation or a pivot axis for a wheel assembly 20 will be dictated by requirements of caster, camber, and other alignment factors associated with the wheel assemblies 20 .
[0059] Continuing to refer to FIGS. 1 - 9 , and more particularly to FIGS. 1 - 5 a beam 44 may constructed to have one or more webs extending in a direction substantially corresponding to a plane containing the transverse 11 b and lateral directions 11 c . In general, a web 66 may extend substantially as a vertical plane. Again, directions are only by way of an example, and not an absolute orientation. A web 66 or multiple webs, may be configured as side plates 66 and, in any event, may extend away from one or more flanges 68 . In certain selected embodiments, two flanges may flank a web 66 . Thus, flanges 68 may be configured as top and bottom plates 68 .
[0060] Note that the standoffs 18 may also be configured as beams 44 having one or more webs 66 , and one or more flanges 68 . In one embodiment, the standoff 18 may include a web 66 or multiple webs 66 , having a variation in cross-section along a lateral direction 11 c . For example, a web 66 of the standoff 18 may be cut away in order to provide operating clearance for the lever arm 58 associated with the tie rod assembly 50 .
[0061] In one embodiment, the flange 68 may be formed so as to include a broken flange 69 . The broken flange 69 , is not actually broken, rather, the flange portion 69 extends in a plane or as a surface intersecting the basic flange 68 . Accordingly, the flanges 68 , 69 accommodate the change in cross-section of the webs 66 of the standoff 18 . To the extent that a wheel assembly 20 should pivot with respect to the standoff 18 and axle 12 , a kingpin assembly 70 may support pivoting. In one embodiment, a kingpin 72 may penetrate a yoke 74 corresponding to a spindle assembly supporting the wheel assembly 20 . Although the spindle is not shown, a spindle serves as the member supporting bearings and rotation of a tire 22 and wheel 24 with respect to the kingpin 72 and the axle 12 . Accordingly, a yoke 74 may capture a bushing 76 . The bushing 76 may capture, together with the yoke 74 , the kingpin 72 extending therebetween. An aperture 77 may penetrate the bushing 76 for receiving the kingpin 72 therethrough.
[0062] The wheel assembly 20 may be provided with a brake drum 78 for braking the wheel assembly 20 with respect to the axle 12 . A spindle plate 80 may extend into the break drum 78 , supporting the spindle about which the tire 22 and wheel 24 rotate. A wheel 24 may be secured to the brake drum 78 or a turntable associated therewith, typically a hub, by lugs 82 . Nuts 84 secured to the lugs 82 may secure the wheel 24 in position.
[0063] In general the apparatus 10 may be configured to operate as a principal axle or an auxiliary axle. Accordingly, a suspension system may be selected from any type of suspension system suitable for mounting the axle 12 to a frame 30 of a vehicle. In one embodiment, the apparatus 10 may be a trailing axle 12 . Similarly, however, a pivotable mount directly to a frame 30 may also lower the axle 12 from a position proximate the frame 30 to a peak position comparatively proximate the ground. Plates 86 , or similar brackets 86 , may secure a swing arm assembly 42 to the frame 30 . An intermediate structure 26 devoted to the apparatus 10 , may or may not be appropriate. The frame 26 may actually be a portion, such as a cross-member 26 , of the organic vehicle frame 30 .
[0064] Likewise, plates 88 or brackets 88 securing the axle 12 to a suspension system may be formed by any suitable means. In the embodiment illustrated, stiffeners 90 are secured to plates 88 in order to create a box-like effect, adding stiffness and strength.
[0065] Referring to FIGS. 4 - 5 , while continuing to refer generally to FIGS. 1 - 9 , an axle 12 may be fabricated from conventional metal sections, or may be fabricated into the beam structure 44 of the axle 12 . In one embodiment, an anchor plate 96 may cross between the webs 66 of the beam 44 , or between the flanges 68 of the beam 44 , or between all four. The anchor plate 96 may be solid, or may be relieved near corners, along certain sections, and the like, as may be advisable to optimize stress management in the beam 44 . In the illustration of FIGS. 4 - 5 , the anchor plate 96 may be positioned to directly support the strut 46 connected to the bracket 14 . Although the brackets 14 and the mounts 16 are illustrated as flat plates 14 , 16 , curvature may be appropriate in certain circumstances. Likewise, a V-shaped, or other cross-sectional surface may serve to stiffen, strengthen, lock, align, or the like, the mount 16 with respect to the bracket 14 .
[0066] Just as the anchor plates 96 may stiffen the beam 44 and support the struts 46 , a stiffener 98 may strengthen the standoffs 18 . As a practical matter, a stiffener 98 may also triangulate between certain of the flanges 68 , and the mount 16 secured to the bracket 14 .
[0067] In certain embodiments, the flanges 68 may extend between the bushing 76 and the mount 16 . Nevertheless, as illustrated in FIGS. 1 - 3 , the flanges 68 may be partial, according to the weight, stress, and access considerations.
[0068] Referring to FIG. 6, a vehicle 100 may include a bed 30 , a cab 120 mounted thereon, and a bed 104 supported thereby. The vehicle 100 may include multiple axles 106 - 116 . For example, the vehicle 100 may be equipped with a leading auxiliary axle 106 . A following auxiliary axle 108 may be added alone, or in combination with the leading auxiliary axle 106 . In a combination with the auxiliary axles 106 , 108 both 106 , 108 , or alone, the auxiliary axle 110 may trail vehicle 100 on a swing arm 42 supported by suitable suspension methods. For example, springs, shackles, air bags, hydraulic systems, and the like may support the loads between an axle 12 and the frame 30 .
[0069] In certain embodiments, an axle 12 , or the apparatus 10 may be installed as the steering axle 112 . In other embodiments, an axle assembly 10 in accordance with the invention may be installed as the forward drive axle 114 , the rear drive axle 116 , or both. Thus, relying on the adaptability of the transverse adjustment of the clearance 23 of the axle mounting surface 25 above an operating surface, the axles 106 - 116 may all be of a type contemplated within the scope of the invention, each adjusted at an appropriate position for the application for which it is designed and installed.
[0070] Referring to FIG. 7, while continuing to refer generally to FIGS. 1 - 6 , an apparatus 10 having an axle 12 with the corresponding bracket 14 and mount 16 may include a standoff 18 extending either straight in a lateral direction 11 c , or extending in a lateral direction 11 c , while angling upwardly or downwardly along a transverse direction 11 b . A drive axle 120 may be encased in the axle 12 , and driven by a differential associated therewith. Accordingly, a hub 122 may connect a wheel assembly 20 to a drive axle 120 . In certain embodiments, an optional drive knuckle 123 may facilitate offsetting the hub 122 from the drive axle 120 . Accordingly, a hub 124 connecting to a wheel assembly 20 may be displaced from the mount 16 a suitable distance. Meanwhile, bearings 126 associated with the axle 12 may be scaled to support a differential connected to the axle 12 . Likewise, bearings 128 may support rotation of the hub 122 at the wheel end of the standoff 18 .
[0071] In one embodiment, a first universal joint 130 may provide rotational power taken from the drive axle 120 and aligned therewith. A second universal joint 132 may deliver power to the hub 122 , accommodating the difference in alignments between the hub 122 , and a drive shaft 134 connected to the first universal joint 130 . A spindle 136 , or a stub axle 136 may rotate in the bearing 128 , supporting the hub 122 . A faceplate 138 or bulkhead 138 may be formed in any suitable shape to support a bearing 128 and axle 136 or spindle 136 . Accordingly, the wheel 24 may mount to the face plate 124 , secured by the lugs 82 . Accordingly, the wheel assembly 20 may rotate with the axle 136 , driven at the rotational velocity or angular velocity of the drive axle 120 , but offset at a different position, in all three dimensions of space, as well as at any suitable angle deemed appropriate for proper tracking of the wheel assembly 20 .
[0072] The standoff 18 may also serve as a gear box, transfer case, or the like. For example, in addition to the drive knuckle assembly 123 , gear reductions and the like may be provided in the standoff 18 . Accordingly, the standoff 18 may be sealed to support an oil bath, or simply to prevent debris from interfering with the smooth operation of the drive knuckle assembly 123 .
[0073] The drive knuckle assembly 123 is by no means required. For example, a drive axle 120 may simply be carried in a floating bearing 128 positioned by the bolts 48 securing the mount 16 to the bracket 14 . In another embodiment, where the wheel assembly 20 is not a drive wheel (e.g. see the drive axles 114 - 116 ), a spindle 136 may be fixed with respect to the standoff 18 . That is, the spindle 136 may be identical to a coasting wheel assembly 20 , such as is used in a conventional, non-powered steering axle 112 . Thus, a castering wheel assembly 20 may be secured as illustrated in FIGS. 1 - 3 , yet a leading auxiliary axle 106 and a following auxiliary axle 108 need not caster. In fact, castering may be problematic, depending on space, alignment, terrain, and other considerations.
[0074] Referring to FIG. 8, a shim 124 may augment the interface between the axle 12 and the standoff 18 . The shim 124 may be thought of as an additional standoff 18 adapted to extend the effective “width” of the apparatus 10 in a lateral 11 c direction. Wheel assemblies may be shimmed wider apart according to the desired configuration of an apparatus 10 to be installed on a vehicle. Moreover, in certain embodiments bolts 48 may be arranged in a manner (e.g. distributed diagonally or horizontally) to provide direct lateral 11 c positioning of the standoff 18 with respect to the axle 12 , or shimmed standoff, as required.
[0075] Referring to FIG. 9, an apparatus 10 may include a standoff 18 having lands 120 and grooves 122 adapted to interleave for supporting the standoff. Lands 120 and grooves 122 on the mount 16 mate with grooves 122 and lands 120 , respectively on the standoff 18 . Thus, the bolts 49 may hold the standoff 18 to the axle 12 , while the lands 120 and grooves 122 (e.g. toothed structures) support the actually operating loads of the apparatus 10 .
[0076] Thus, in an apparatus and method in accordance with the invention, one may fabricate a lightweight, height-adjustable axle. Different embodiments of standoffs may be used. Different embodiments of axles 12 may be used. Different types of beams 44 may be configured. Different types of mounting mechanisms and the like for securing wheel assemblies to rotate with respect to the axle 12 , may be used in order to support steering, driving, trailing, and auxiliary leading or following.
[0077] From the above discussion, it will be appreciated that the present invention provides a lightweight, height-adjustable axle for use as a steering axle, drive axle, auxiliary leading axle, auxiliary following axle, or auxiliary trailing axle for a truck. The apparatus may be mounted by any suitable, conventional suspension system in the art of principal axle mounting or auxiliary axle mounting for trucks and the like.
[0078] The present invention may be embodied in other specific forms without departing from its 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 lightweight axle assembly may include a bracket at each end thereof for receiving a mount at one of a plurality of positions thereon. The mount may include a standoff for spacing an actual wheel assembly a suitable distance from the bracket. The axle may be formed to include a beam for suitable cross section including I-beams, channels, or boxes, as well as cylindrical tubes. Wheels may be mounted to spindles rigidly attached, to driving axles contained within the axle assembly, or to kingpins secured to the mounts. The axle may be adjusted to accommodate a broad range of suitable, relative, distances between the mounting surface (top or bottom of the axle end) and the center line of a wheel assembly associated with the axle. Forged mounts may be manufactured to accomplish structural objectives. Meanwhile, areas of less stress may be fabricated from lighter materials of various unconventional configurations. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation, under 35 U.S.C. § 120, of copending international application No. PCT/EP03/01502, filed Feb. 14, 2003, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. 102 08 472.6, filed Feb. 27, 2002; the prior applications are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention is concerned with a household appliance having a useful space, which can be closed by a door, and a storage space, which is disposed below the useful space and into which the store can be displaced. The door is associated with a guide system having at least one slotted-guide track, by which the door is guided during a movement from a closed position to the storage space.
German Published, Non-Prosecuted Patent Application DE 199 06 913 discloses a generic household appliance having a door that closes a useful space in the household appliance. Below the useful space, an opening having a guide system disposed in it is formed in a horizontal plane. The door can be slid into the opening through the guide system.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a household appliance that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that has an enlarged useful space while the overall size remains the same.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a household appliance, includes a housing defining a useful space and a door opening, a door pivotally connected to the housing and selectively closing off the door opening in a closed position thereof, the door having a guide element, a storage space disposed below the useful space and the door is displaced selectively into the storage space, and a guide system having at least one slotted-guide track in which the guide element is guided during a movement of the door from the closed position into the storage space, the slotted-guide track having a starting section initially guiding the door upward during a movement from the closed position.
The slotted-guide track has a starting section that initially guides the door upward during a movement from its closed position. By such a lifting movement, a lower edge of the door, which edge pivots into the storage space, is initially displaced upward. During the movement of the door into this storage space, the lower edge of the door, therefore, describes a pivoting region that is spaced apart from a base of the storage space and does not intersect the plane of the base. The movement of the door into the storage space, therefore, requires an extremely low storage-space height. The low storage-space height advantageously enables the useful space to be enlarged without changing the overall size of the household appliance.
In accordance with another feature of the invention, the angle of ascent of the starting section is 30° to 60° and, in particular, approximately 45°. This, first, results in an ergonomically favorable door movement for an operator. Second, at the same time as the movement according to the invention upward, the door already can be executing a pivoting movement. The lifting movement of the door is, therefore, not restricted by an upper door boundary, for example, an upper edge strip.
In accordance with a further feature of the invention, to achieve an ergonomically favorable and harmonic movement of the door, the starting section of the slotted-guide track merges into a substantially horizontal slide-in section, in which the door is guided into the storage space in a substantially horizontal plane.
In accordance with an added feature of the invention, a space divider is disposed in a region of the storage space below the slotted-guide track. The space divider divides the storage space into a first storage space, in which the door and the guide system are disposed, and into a second storage space. In the second storage space, baking sheets or other accessories, for example, can be stored. In this slide-in section, the door moves rectilinearly in a plane with the slotted-guide track. As a result, a harmonic movement of the door is obtained and a tilting of the door can be avoided.
In accordance with an additional feature of the invention, it is particularly advantageous if the starting section is no more than 30% of the entire length of the slotted-guided track. In addition to an ergonomically favorable pivoting profile of the door, such a configuration has the effect that the pivoting region of the lower edge of the door protrudes only slightly into the storage space. The above-mentioned space divider can, therefore, divide advantageously virtually the entire storage space without cutting across the pivoting region of the lower edge of the door.
In accordance with yet another feature of the invention, the door can be mounted pivotally about a hinge pin, which is fixed on the housing and which is guided displaceably in a guide rail of the door. This results in an advantageous, ergonomically favorable movement of the door for the operator. In addition, the structural outlay on the movement of the door into the storage space is reduced by the realization of the pivot pin in a manner fixed on the housing because a moving hinge pin and associated moving guide track can be avoided.
In accordance with yet a further feature of the invention, it is advantageous if the hinge pin, which is fixed on the housing, is disposed level with the slide-in section of the slotted-guide track. A pivoting movement of the door, therefore, takes place only if the guide element runs in the starting section of the slotted-guide track. When the guide element runs in the region of the slide-in section, the guide element is already in its horizontal position.
In accordance with a concomitant feature of the invention, the invention is not restricted to a configuration of the storage space below the useful space. On the contrary, the storage space may also be disposed at the side of or above the useful space.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a household appliance, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective front view of a first exemplary embodiment of a cooking appliance according to the invention with an opened door;
FIG. 2 is a fragmentary, enlarged perspective and partially hidden view of a cutout of a door handle according to the invention with an associated bearing housing;
FIG. 3 is a fragmentary, side cross-sectional view of the handle of FIG. 2 along section line A-A;
FIG. 4 is a fragmentary, side cross-sectional view of the door handle of FIG. 1 along section line B-B;
FIG. 5 is a diagrammatic, enlarged, cross-sectional view of a detail of the handle of FIG. 4 ;
FIG. 6 is a fragmentary, perspective and partially hidden view of a second exemplary embodiment of a cooking appliance according to the invention;
FIG. 7 is a fragmentary, perspective and partially hidden view of a storage space module of the cooking appliance of FIG. 6 ;
FIG. 8 is a fragmentary, enlarged, perspective view of a detail of the module of FIG. 7 ;
FIG. 9A is a fragmentary, side elevational and partially hidden view of a first part of an opening process of the mechanism of FIG. 8 ;
FIG. 9B is a fragmentary, side elevational and partially hidden view of a second part of an opening process of the mechanism of FIG. 8 ;
FIG. 9C is a fragmentary, side elevational and partially hidden view of a third part of an opening process of the mechanism of FIG. 8 ;
FIG. 10 shows a side sectional illustration of an upper and lower section of the door of the cooking appliance from FIG. 6 ;
FIG. 11 is a side elevational view of the mechanisms of FIGS. 7 and 8 along line D-D in FIG. 7 in a first position;
FIG. 12 is a side elevational view of the mechanism of FIG. 11 in a second position;
FIG. 13A is a schematic front elevational view of a variant of the household appliance according to the invention with the storage space module on the bottom thereof;
FIG. 13B is a schematic front elevational view of a further variant of the household appliance according to the invention with the storage space module on the top thereof; and
FIG. 13C is a schematic front elevational view of another variant of the household appliance according to the invention with the storage space module on the side thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a cooking appliance 1 in a first exemplary embodiment of a household appliance according to the invention. The cooking appliance 1 has front-side operating and display elements 2 with an associated non-illustrated control unit. Furthermore, a cooking space 3 is provided in the cooking appliance 1 . The cooking space 3 is bounded by a muffle 4 that is open on the front side. A front-side muffle frame 8 frames the front-side opening of the muffle 4 . The cooking space 3 can be closed by a door 5 that is mounted pivotally about a horizontal hinge pin or articulation axis 12 . The door 5 has an inner door window 7 and an outer door window 9 of glass or glass ceramic. A door handle 17 , which is mounted pivotally in a bearing housing 21 , is provided on an upper end side 6 of the door 5 .
FIG. 2 shows the configuration including the door handle 17 and the bearing housing 21 in a perspective illustration enlarged in some sections. For simplification purposes, the inner and outer door windows 7 , 9 of the door are omitted. The door handle 17 has a handle strip 13 that is connected to a pivoting part 16 through bearing blocks 15 . The pivoting part 16 forms the upper end side 6 of the door 5 and has pivot pins 19 on both sides in the longitudinal direction. The pivot pins 19 are mounted rotatably in the bearing housing 21 . Both the bearing housing 21 and the pivoting part 16 are, preferably, manufactured as an injection molded part from a duroplastic (thermosetting plastic material). Stiffening elements 23 are formed on both longitudinal sides of the bearing housing 21 . These stiffening elements 23 dip into an inner space 41 of the door and are fastened releasably, for example, screwed, to lateral edge strips 25 of the door 5 .
Additional stiffening elements 27 are formed on the front side of the bearing housing 21 . According to FIG. 3 , the stiffening elements 27 are in contact with the outer door window 9 . FIG. 3 shows a sectional illustration along the line A-A from FIG. 2 , in which the door windows 7 , 9 are indicated in dashed lines. Accordingly, the stiffening element 27 is in contact with the outer door window 9 while the inner door window 7 rests, with the interposition of a seal 29 , against a contact surface 22 of the bearing housing 21 . FIG. 3 , furthermore, reveals that the bearing housing 21 has a supporting surface 31 . The supporting surface 31 is disposed between the lateral pivot pins (journals) 19 and extends in the axial direction of the pivoting part 16 over virtually the entire length of the pivoting part 1 . A corresponding mating surface 33 of the pivoting part 16 is in contact with the supporting surface 31 . During the pivoting movement of the door handle 17 , the pivoting part 16 thereof is, therefore, supported on the supporting surface 31 . Furthermore, two stops 35 , 37 that restrict and bound a pivoting region of the door handle 17 are formed on the bearing housing 21 .
As illustrated in FIG. 2 , the door handle 17 is assigned a tension spring 39 that pre-stresses the door handle 17 in a pivoting direction. The tension spring 39 is provided below the bearing housing 21 and extends in the longitudinal direction of the bearing housing 21 . The tension spring 39 is suspended freely in the inner space 41 of the door that is formed between the door windows 7 , 9 . The freely suspended configuration of the tension spring 39 within the inner space 41 of the door makes it possible to achieve a free expansion and, therefore, low-wear loading of the tension spring 39 .
The two ends of the tension spring 39 are connected in each case through a first tension cable 43 to the pivoting part 16 to transmit a tension spring force to the pivoting part 16 . The first tension cables 43 are guided through deflecting rollers 45 , which are mounted rotatably on the stiffening elements 27 , to radial cam plates 47 . The radial cams 47 are connected on both sides in a rotationally fixed manner to the longitudinal ends of the pivoting part 16 . Each of the first pulling cables 43 here is fixed on the circumference of the cam plate 47 at a fastening point 46 . As a result, the tension spring 39 pre-stresses the door handle 17 against the first stop 35 and subjects the door handle 17 to a first torque M 1 in a pivoting direction ( FIG. 4 ). To protect against contamination, the radial cams 47 are disposed within lateral cutouts of the pivoting part 16 . Covering sections 18 of the pivoting part 16 cover the cutouts on the end side.
A second tension cable 48 engages on the circumference of each of the radial cams 47 . The second tension cable 48 is guided around the cam plate 47 in the direction counter to the first pulling cable 43 and is fixed on the circumference of the cam plate 47 at the fastening point 46 . The first and second tension cables 43 , 48 and the radial cams 47 form constituent parts of a control mechanism 38 . The control mechanism 38 transmits a pivoting movement of the door 5 to the door handle 17 , i.e., when the door 5 is pivoted in a first pivoting direction, the control mechanism 38 pivots the door handle 17 in a second pivoting direction, counter to the first pivoting direction. The construction and functioning of the control mechanism 38 are explained below with reference to FIG. 4 .
FIG. 4 shows an upper and lower cutout of the door 5 in a sectional illustration along the line B-B from FIG. 1 . The door 5 is disposed in a closed position. A driving drum 54 that serves as a driving part of the control mechanism is disposed in the lower section of the door 5 . Starting from the driving drum 54 , a rotational movement is transmitted through the tension cable 48 to the radial cam 47 . The tension cable 48 engages on the circumference of the radial cam 47 . The tension cable 48 , therefore, converts the rotational movement of the driving drum 54 into a rotational movement of the radial cam 47 .
If the door 5 is pivoted downward from its closed position, which is shown in FIG. 4 , the driving drum 54 rotates. The introduction of movement into the driving drum 54 is described later on with reference to the second exemplary embodiment. The rotational movement of the driving drum 54 is transmitted through the tension cable 48 to the radial cam 47 . As a result, a second torque M 2 , which is directed counter to the first torque M 1 , is exerted on the door handle 17 . The effect that can be achieved as a result is that the horizontal alignment of the door handle 17 that is shown in FIG. 4 is substantially retained regardless of the pivoting position of the door 5 .
If an operator exerts an upwardly directed actuating force F on the door handle 17 shown in FIG. 4 —for example, during transportation of the cooking appliance—the resultant pivoting movement of the pivoting part 16 of the door handle in the clockwise direction is absorbed by the tension spring 39 . This prevents the pivoting movement of the door handle 17 , which movement is directed in the clockwise direction of FIG. 4 , from being transmitted to the control mechanism 38 . The tension spring 39 , accordingly, acts, as a safeguarding device that prevents damage to the control mechanism 38 .
The magnitude of the spring force of the tension spring 39 and/or the torque M 1 exerted thereby is based on a minimum value for the spring force of the tension spring 39 . This minimum value corresponds approximately to the frictional forces that have to be overcome to restore the door handle 17 after an actuating force F is no longer exerted on the door handle 17 . The tension spring 39 is dimensioned such that the abovementioned minimum value is approximately 10% to 20% of the spring force of the tension spring 39 . The spring force of the tension spring 39 is, therefore, approximately five to ten times larger than this minimum value. When the door handle 17 is actuated incorrectly, for example, as a result of the upwardly directed actuating force F being exerted (see FIG. 4 ), damage to the control mechanism 38 is, thus, prevented. At the same time, the comparatively large spring force permits an ergonomically favorable operating feel during a normal opening or closing actuation of the door handle 17 by the operator.
The radius of the cam plate 47 is very important to ensure that the movement of the hinge rod 55 is transmitted to the door handle 17 in a correct transmission ratio. On one hand, the radius of the cam plate 47 determines the length of the lever arm and, thus, the magnitude of the torque by which the pulling cables 43 , 48 act on the cam plate 47 . On the other hand, the cam-plate radius defines the transmission ratio by which a drive movement of the control mechanism 38 is converted into a pivoting movement of the door handle 17 . In FIG. 5 , the lever-arm lengths r 1 , r 2 of the cam plate 47 , which lengths are associated with the first and the second tension cable 43 , 48 , are configured such that they differ in magnitude. FIG. 5 shows an enlarged illustration of the radial cam 47 from FIG. 4 .
In FIG. 5 , the points of action of the pulling cables 43 and 48 are designated A 1 and A 2 . During an operation for opening the door 5 , the point of action A 1 of the pulling cable 43 moves through an angle of rotation of approximately 90° in the counterclockwise direction along the circumference of the cam plate 47 . Over this angle of rotation, the lever arm length r 1 is substantially constant. The torque M 1 exerted on the door handle 17 is, therefore, constant during the pivoting movement of the door 5 . At the same time, the engagement point A 2 of the tension cable 48 moves through an angle of rotation section of approximately 90° in the counter-clockwise direction (with respect to FIG. 5 ) along the circumference of the radial cam 47 . Over this angle of rotation, the lever arm length r 2 is reduced during a pivoting movement of the door 5 from its closed position; that is to say, in the horizontal door position, the torque M 2 exerted on the door handle 17 is the lowest possible. In the horizontal door position, the torque M 2 counteracts a weight of the door 5 ; the weight of the door 5 keeps the door 5 stably in its horizontal position. The torque M 2 , which is reduced in the horizontal door position, is, therefore, not capable of compensating for the weight of the door. The stable position of the door in its horizontal position is, therefore, not adversely affected by the torque M 2 .
A radial cam 47 that is formed eccentrically enables the transmission ratio of the control mechanism 38 to be changed as a function of the pivoting position of the door 5 . It is thus possible to compensate for drive losses of the control mechanism 38 , which are produced, for example, at the beginning of a pivoting movement of the door as a result of expansion of the pulling cables 43 , 48 or of play in the control mechanism 38 .
FIG. 6 shows a cooking appliance according to a second exemplary embodiment of the present invention. The cooking appliance has a useful space module 83 , which is indicated by a chain-dotted line and in which the cooking appliance muffle 3 (not illustrated) is disposed. A storage space module 79 is disposed below the useful space module 83 . The storage space module 79 has a storage space 61 in which a guide system 58 for the door 5 is provided. The guide system 58 enables the cooking appliance door 5 (illustrated by dashed lines) to be displaced into the storage space module 79 . According to FIG. 6 , the storage space module 79 serves as a base or foundation on which the useful space module 83 is mounted. The storage space module 79 is configured as an upwardly open sheet-metal housing. Step-shaped abutment shoulders 85 are formed on the upper edge of the side walls 80 of the sheet-metal housing 79 . The useful space module 83 rests on the contact shoulders 85 in a positionally correct manner, as indicated in FIG. 6 . The operating and display elements 2 , which are shown in FIG. 1 , and an associated control unit are provided in the useful space module 83 . The operating and display elements 2 , here, together with the associated control unit, can function independently of the stowage-space module 79 .
The control mechanism 38 of the second exemplary embodiment has, as driving part, a rotary shaft 57 on which the driving drum 54 , which is already mentioned in the first exemplary embodiment, is formed. The rotary shaft 57 is operatively connected to a guide element 59 of the guide system 58 .
The construction and the manner of operation of the guide system 58 for the door 5 and the production of a driving movement for the control mechanism 38 are explained below.
As illustrated in FIG. 6 , the guide element 59 is part of the guide system 58 , with the aid of which the door 5 is pushed, during an opening process, into the storage space 61 provided below the cooking space 3 . FIGS. 6 and 7 reveal that the guide system 58 has slotted-guide tracks 63 . The slotted-guide tracks 63 are formed in the two opposite side walls 80 of the storage space module 79 . The opposite slotted-guide tracks 63 guide sliders 60 of the guide element 59 therein. The sliders 60 are welded to each other through a connecting rod 62 . The guide element 59 is, therefore, guided in the opposite slotted-guide tracks 63 in the manner of a guide carriage. Between the two sliders 60 , adjusting levers 67 are welded to the connecting rod 62 . As illustrated in the enlarged perspective cutout of FIG. 8 , the adjusting levers 67 are connected in a form-fitting manner to the rotary shaft 57 of the control mechanism 58 . The rotary shaft 57 is indicated in FIGS. 6 and 7 by chain-dotted lines.
The above-mentioned form-fitting connection between the adjusting levers 67 of the guide carriage 59 and the rotary shaft 57 of the door 5 is illustrated in FIG. 8 . The inner and outer door windows 7 , 9 of the door 5 have been omitted from FIG. 8 . Accordingly, the rotary shaft 57 is mounted rotatably in the opposite edge strips 25 of the door 5 . For the form-fitting connection, the adjusting levers 67 of the guide carriage 59 each have a rectangular cutout 69 ( FIG. 8 ). A corresponding, rectangular shape section 71 of the rotary shaft 57 is mounted in the cutout 69 . The lateral edge strips 25 of the door 5 are provided in the outward direction in each case with a U-shaped groove that serves as a guide rail. In these guide rails 25 , respective bearing rollers 65 are guided displaceably on both sides. The bearing rollers 65 are fastened to the side wall 80 of the storage space module 79 . The U-shaped groove, which serves as a guide rail, is constructed on its lower end side with an open end 26 . When the door is removed, as will be described at a later stage in the text, the housing-mounted bearing roller 65 can be released from the associated guide rail 25 by way of the open end 26 .
Each of the opposite slotted-guide tracks 63 has a starting section 90 and a slide-in section 91 . According to FIGS. 9A and 9C , an angle of inclination of the starting section 90 is approximately 45°. The starting section 90 , furthermore, takes up approximately 30% of the entire length of the slotted-guide track 63 while the transition between the starting section 90 and the slide-in section 91 has a curved profile. The slide-in section 91 runs substantially in a horizontal plane. The bearing rollers 65 , which are fixed on the housing, are disposed approximately level with the slide-in section 91 of the slotted-guide track 63 .
The course of movement of the guide carriage 59 of the door 5 in the slotted-guide tracks 63 is described with reference to FIGS. 9A to 9C . FIG. 9A shows the door 5 in its closed position. In the closed position, the sliders 60 of the guide carriage 59 are in the starting section 90 of the slotted-guide track 63 . During an opening movement of the door 5 from its closed position shown in FIG. 10 , the sliders 60 of the guide carriage 59 are initially displaced upward. As a result, the adjusting levers 67 of the guide carriage 59 lift the door 5 upward. With this lifting movement of the door 5 , a lower end side 93 of the door 5 , which side pivots into the storage space 61 , is displaced, at the same time, upward away from a base 117 of the storage space module 79 , as is revealed in FIG. 9B . As a result, a pivoting region S of the lower end side 93 , which region protrudes into the storage space 61 and is indicated by a chain-dotted line, is reduced. After the guide carriage 59 is moved from the starting section 90 into the horizontal slide-in section 91 ( FIG. 9C ), the door 5 is in a horizontal plane, in which it can be slid into the storage space 61 . During the pivoting movement of the door 5 , a pivoting angle between the door 5 and the guide block 59 changes. Because the rotary shaft 57 of the control mechanism 38 is mounted in a form-fitting manner in the adjusting levers 67 of the guide slide 59 , the change in the pivoting angle between the door 5 and the guide carriage 59 causes a rotation of the rotary shaft 57 . That is to say, during the pivoting movement of the door 5 , the rotary shaft 57 is inevitably rotated by the guide element 59 .
The manner in which the control mechanism 38 transmits the inevitable rotation of the rotary shaft 57 to the door handle 17 is explained with reference to FIG. 10 . FIG. 10 shows a side sectional view of the upper and lower section of the door 5 according to the second exemplary embodiment. This reveals that the adjusting lever 67 protrudes through an access opening 129 of the door 5 into the interior space 41 of the door and is connected in a form-fitting manner to the rotary shaft 57 . As can be gathered from FIGS. 8 and 10 , the rotary shaft 57 is configured with a driving drum 54 , which is disposed in a rotationally fixed manner on the rotary shaft 57 . The driving drum 54 is in engagement circumferentially with the tension cable 48 . As in the first exemplary embodiment, the tension cable 48 is connected to the door handle 17 .
During the pivoting movement of the door 5 , a pivoting movement, therefore, arises between the guide carriage 59 and the door 5 . As a result, the rotary shaft 57 is rotated inevitably. The rotational movement of the rotary shaft 57 is transmitted through the driving drum 54 to the tension cable 48 . The tension cable 48 converts the rotational movement of the rotary shaft 57 into a rotational movement of the radial cam 47 and subjects the door handle to the second torque M 2 , which is directed counter to the first torque M 1 , on the door handle 17 . The door handle 17 , therefore, retains its horizontal alignment regardless of the pivoting position of the door 5 .
In contrast to FIG. 4 of the first exemplary embodiment, in FIG. 10 , the first tension cables 43 , which engage on both sides on the radial cams 47 of the pivoting part 16 of the door handle 17 , are not connected to a common tension spring. Rather, according to FIG. 10 , each of the first tension cables 43 is associated with a dedicated tension spring 39 . The tension spring 39 is fastened at one end of the spring to the edge strip 25 of the door 5 . The other end of the tension spring 39 is coupled to the tension cable 43 through a retaining eyelet 75 . As a result, the door handle 17 is subjected to the first torque M 1 in the counterclockwise direction.
The control mechanism 38 shown in FIG. 10 has a third tension cable 77 . The third tension cable 77 is, on one hand, in circumferential engagement with the driving drum 54 of the rotary shaft 57 and is guided about the driving drum 54 in the opposite direction to the second tension cable 48 . On the other hand, the third tension cable 77 is connected to the retaining eyelet 75 of the first tension cable 43 . The first, second, and third tension cables 43 , 48 , 77 of the control mechanism 38 form a closed cable control that envelops the radial cam 47 and the driving drum 54 to transmit the rotational movement to the door handle 17 .
To tighten the closed cable control 43 , 48 , 77 , a tightening spring 79 is integrated in the third tension cable 77 . The tightening spring 79 serves to tighten the closed cable control 43 , 48 , 77 . In addition, the tightening spring 79 increases the torque M 1 that is exerted by the tension spring 39 on the door handle 17 . Therefore, both the tightening spring 79 and the tension spring 39 are present for exerting the torque M 1 . It is, therefore, advantageously possible for use to be made of two comparatively small springs that take up only a small amount of space in the limited inner space 41 of the door.
If the operator, for example, during transportation of the cooking appliance 1 , exerts an upwardly directed actuating force F on the door handle 17 shown in FIG. 4 , the resultant pivoting movement of the pivoting part 16 of the door handle in the clockwise direction is absorbed by the tension spring 39 and by the tightening spring 79 . The resultant pivoting movement of the pivoting part 16 is, therefore, not transmitted from the door handle 17 to the control mechanism 38 . As a result, damage to the control mechanism 38 is prevented.
The dimensioning of the spring force of the tension springs 39 , 79 depend on the minimum value for the spring force, which value is specified in conjunction with FIG. 4 .
Furthermore, the tension cables 43 , 48 , 77 can be provided with adjusting elements for adjusting a tensile stressing. By the adjusting elements, the tension cables provided on both sides of the door sides can be acted upon with an identical tensile stress. As a result, a synchronous operation of the two control mechanisms 38 is achieved.
A weight-balancing configuration 94 for the door 5 of the second exemplary embodiment is described below with reference to FIGS. 7 , 11 , and 12 . During a movement of the door 5 , the weight-balancing configuration 94 exerts a balancing force on the door 5 , which force acts counter to the weight of the door 5 . The weight of the door 5 is, therefore, not absorbed by the operator during a door movement, but, rather, by the weight-balancing configuration 94 .
FIG. 7 shows, in a perspective view, the storage space module 79 , of which a space divider 111 (described later on) is illustrated separately. On each of the opposite side walls 80 , the weight-balancing configuration 94 has a pivoting lever 95 . The pivoting lever 95 is mounted pivotally on the opposite side walls 80 through a lever spindle 97 . FIG. 11 shows one of the side walls 80 in an enlarged side elevational view along the line D-D from FIG. 7 . Accordingly, the pivoting lever 95 protrudes into the starting section 90 of the slotted-guide track 63 and is in engagement with the slider 60 of the guide carriage 59 . A pivoting region of the pivoting lever 95 is configured such that the pivoting lever 95 is in engagement with the slider 60 of the guide carriage 59 only in the region of the starting section 90 . By contrast, in the horizontal section 91 , the pivoting lever 95 is disengaged from the slider 60 of the guide carriage 59 . The pivoting lever 95 is connected to a tension spring 103 . The tension spring 103 is fastened to the side wall 80 . In FIG. 11 , the tension spring 103 pre-stresses the pivoting lever 95 in the counter-clockwise direction.
When the door 5 , which is illustrated by dashed lines in FIG. 11 , is pivoted from its closed position downward into the horizontal position, the slider 60 runs from the starting section 90 into the horizontal section 91 of the slotted-guide track 63 . During this movement, the slider 60 of the guide slide 59 presses against the spring-pre-stressed pivoting lever 95 . The pivoting lever 95 , therefore, subjects the sliding component 60 to a balancing force. The balancing force acts counter to the weight of the door 5 .
As illustrated in FIG. 11 , the pivoting lever 95 is pressed by the spring 103 against a first end stop 99 , which is formed by a rubber support. In the position shown in FIG. 11 , the pivoting lever 95 permits an initial movement of the slider 60 of the guide carriage 59 out of the closed position of the door 5 . During this initial movement, the slider 60 does not engage with the pivoting lever 95 . According to FIG. 11 , the slider 60 comes into contact with the pivoting lever 95 only at a pivoting angle of the door 5 of approximately 20°. This simplifies the initial movement of the door 5 out of its closed position for the operator. Moreover, the pre-stressed pivoting lever 95 according to FIG. 11 acts as a stop against which the slider 60 of the guide carriage 59 strikes during the opening movement of the door 5 . A certain pivoting position of the door 5 is, thus, signaled to the user. In the present case, this pivoting position corresponds to a removal position (described later on), in which a simple removal of the door 5 from the guide system 58 is made possible.
Furthermore, the weight-compensating configuration 94 has a pivotally mounted retaining element 105 that is pre-stressed by a spring 106 . During the previously described initial movement of the door 5 , the spring-pre-stressed retaining element 105 presses the slider 60 of the guide carriage 59 in the direction of the pivoting lever 95 . As a result, the door 5 is retained stably in the removal position shown in FIG. 11 .
FIG. 12 shows the door 5 mounted horizontally and slid into the storage space 61 . The slider 60 of the guide carriage 59 of the door 5 is in the horizontal slide-in section 91 of the slotted-guide track 63 . During the movement of the slider 60 in the region of the slide-in section 91 of the slotted-guide track 63 , the pivoting lever 95 is disengaged from the slider 60 . The pivoting lever 95 , therefore, does not exert any balancing force on the door 5 . While the slider 60 runs in the slide-in section 91 of the slotted-guide track 63 , the pivoting lever 95 is in the clockwise direction, by the spring 103 , against a second end stop 101 , which is, likewise, formed by a rubber support.
The pivoting lever 95 has a driver 107 . The driver 107 of the pivoting lever 95 protrudes, in FIG. 12 , into the slotted-guide track 63 . According to FIG. 12 , the slider 60 has been displaced from the starting section 90 into the slide-in section 91 of the slotted-guide track 63 . The adjusting lever 95 is pre-stressed against the second end stop 101 and is in a holding position. When the door 5 is displaced out of the storage space 61 , the slider 60 comes into engagement with the driver 107 of the pivoting lever 95 . As a result, the pivoting lever 95 is brought out of its holding position and comes, once again, into a pressure contact with the slider 60 of the guide carriage 59 . As a result, the pivoting lever 95 can, once again, exert the compensating force on the guide carriage 59 during a pivoting movement of the door 5 .
The releasable mounting of the door 5 on the guide system 58 is explained below with reference to FIG. 8 . Due to the releasable mounting of the door 5 in the guide system 58 , the door 5 can easily be removed for cleaning. As already described with reference to FIG. 8 , the adjusting levers 67 have a rectangular cutout 69 . The corresponding rectangular shape section 71 of the rotary shaft 57 is mounted in the rectangular cutout 69 . This produces a form-fitting connection between the guide carriage 59 and the rotary shaft 57 . A locking element 73 that, according to FIG. 8 , is mounted on the rotary shaft 57 is explained below. The locking element 73 can be displaced between a locking position and a release position. In the release position, the locking element 73 releases the mounting of the rotary shaft 57 in the adjusting lever 67 . In a locking position of the locking element 73 , the rotary shaft 57 is connected non-releasably to the adjusting lever 67 .
The space divider 111 that is mentioned in conjunction with FIG. 7 is explained in the following text. As emerges, in particular, from FIG. 6 , the space divider 111 is disposed in the storage space module 79 . The space divider 111 divides the storage space 61 into a first storage space 61 a and a second storage space 61 b . The space divider 111 has a horizontal intermediate base 113 and side walls 115 . The door 5 can be displaced into the first storage space 61 a . The space divider 111 also separates the guide system 58 , which is formed from the slotted-guide track 62 and guide carriage 59 , and the weight-balancing configuration 94 from the second storage space 61 b . Baking sheets or other accessories may be stored in the second storage space 61 b.
As emerges from FIGS. 9A to 9C , the space divider 111 is disposed below the starting section 90 and the slide-in section 91 of the slotted-guide track 63 . The intermediate base 113 together with the side walls 115 and a housing base 117 form an access opening 119 . The latter is disposed spaced apart from the pivoting region S (indicated by a chain-dotted line) of the lower end side 93 of the door 5 . Display elements 121 ( FIGS. 7 and 8 ) are provided in the region of the access opening 119 of the second storage space 61 b . The display elements 121 are configured as cams or protuberances that are fastened to the base 117 of the storage space 61 . The display elements 121 indicate to the operator a maximum permissible length for objects that can be stored in the second storage space 61 b without protruding into the pivoting region S of the lower end side 93 of the door 5 . Appliance front-side panels 123 are formed on the side walls 115 of the space divider 111 ( FIG. 7 ). The panels 123 serve for concealing the first storage space 61 a from view. In addition, a collecting or drip channel 125 is provided in the housing base 117 , in the region of the appliance front-side access opening 119 , to keep the second storage space 61 b free from contaminants, for example, dripping condensation water.
FIGS. 13A to 13C illustrate, schematically, variants of the household appliance according to the invention. According to FIG. 13A , the useful space module 83 and the storage space module 79 are shown separately from each other. The construction and the manner of operation of the two modules 79 , 83 corresponds to that of the preceding figures. The storage space module 79 and the useful space module 83 are manufactured, first of all, independently of each other as separate constructional units. The storage space module 79 and the useful space module 83 are, then, joined together in an assembly step to form the household appliance. According to FIG. 13A , the storage space module 79 serves as a pedestal on which the useful space module 83 is placed in the arrow direction.
In contrast to FIG. 13A , in FIG. 13B , the storage space module 79 is disposed above the useful space module 83 . The door 5 can, therefore, be displaced upward into the storage space 61 of the storage space module 79 . In FIG. 13C , the storage space module 79 is disposed upended. According to FIG. 13C , the storage space module 79 , which is disposed upended, is fastened to one side of the useful space module 83 . The door 5 can, therefore, be displaced into the storage space 79 , which is disposed at the side of the useful space module 83 . | A household device includes a useful storage volume that can be closed by a door and a storage compartment disposed below, above, or to the side of the useful storage volume into which the door can be displaced. The door is associated with a guiding system including at least one slide track, wherein a guiding element associated with the door is guided by displacing the door from a closed position and moving it into the storage compartment. The slide track includes a start section that initially guides the door in an upward direction when it moves out of the closed position. Such a configuration has the same size as conventional household device with an increased useful storage volume. | 4 |
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for treating tail yarns in textile spindle assemblies of textile spinning machines, twisters or the like, more particularly to the improvement of an apparatus for holding and automatically releasing tail yarns, for example, separated ends of yarns wound on bobbins including portions interconnecting the bobbins and spindle assemblies.
When the doffing operation for changing completed yarn packages to empty bobbins is automatically conducted by using auto-doffers in textile spinning machines, twisters or the like, it is necessary to securely fix each tail yarn wrapped several turns on a tail yarn winding portion formed on a base portion of a spindle so as not to move for the purpose of making sure the automatic yarn winding on the bobbin. If it happens that yarn underwindings formed on the tail yarn winding portion move by a slight force, the yarn underwindings are loosened on rising of a ring rail to a position where the yarn is wound on the bobbin, which causes the disordered position of a traveler. Consequently, yarn breakages are liable to occur at the start of the operation.
The greatest cause of hindering the tail yarn from the secure fixing on the tail yarn winding portion is the presence of the yarn underwindings wound on the tail yarn winding portion. Namely, the tail yarn is wrapped several turns on the tail yarn winding portion such as a knurled surface formed on the base portion of the spindle so as not to move. However, an interconnecting yarn formed between the bobbin and the tail yarn winding portion is separated on the subsequent doffing operation, and a new tail yarn is further wrapped several turns on the yarn underwindings remaining on the tail yarn winding portion to repeat the doffing operation. A new tail yarn is wrapped several turns on the yarn underwindings on all such occasions.
When a new tail yarn is further wrapped on the yarn underwindings which are residual tail yarns previously wrapped, the fixing effect of the yarn underwindings by the knurled surface and the like is lost, which permits the yarn underwindings to move by a slight external force, thereby loosening the yarn underwindings.
Previously, in order to eliminate such inconvenience, the yarn underwindings have been periodically manually removed by use of a cutter or the like while the machine is stopped. However, such a prior-art method is reduced in the operation efficiency of the machine, because the operation is complex, labor intensive and time-consuming.
Then, for the purpose of solving such problems of the prior art to securely fix the tail yarn on the base portion of the spindle and to surely remove the yarn underwindings during the machine operation, the present invention has formerly proposed an apparatus for treating the tail yarn which comprises an upper slit ring fixedly mounted on the base portion of the spindle, a cylindrical member having a lower slit ring at an upper end thereof and a lower portion outwardly expandable by centrifugal force, and a guiding surface fixed on a lower part of the base portion of the spindle, the cylindrical member being axially slidably fitted on the base portion of the spindle beneath the upper split ring and mounted so that a lower end of the expandable portion thereof capably comes into contact with the guiding surface, the upper slit ring and the lower slit ring being pressed together to form a tail yarn gripping means, whereby the expansion of the lower portion of the cylindrical member by centrifugal force causes the cylindrical member to slide axially downward to release a pressed state between the upper slit ring and the lower slit ring (U.S. Pat. No. 4,796,442).
However, in the use of such an apparatus, the lower portion of the cylindrical member gets fatigued by repetition of its expansion and restoration to weaken the restoring force thereof upon standstill of the spindle, which results in an decrease in the pressing force of the lower slit ring to the upper slit ring, whereby it happens that the tail yarn can not be securely fixed to the tail gripping means.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an apparatus for treating a tail yarn which has a lower portion of a cylindrical member not reduced in restoring force even if used for a long period of time and can maintain the effect of fixing securely the tail yarn (interconnecting yarn) to a tail yarn gripping means.
Another object of the invention is to provide the apparatus for treating the tail yarn which can easily remove yarn underwindings, when the yarn underwindings are not released from the tail yarn gripping means under adjustment in the case that the apparatus for treating the tail yarn is newly installed and can improve the effect of fixing securely the tail yarn (interconnecting yarn) to the tail yarn gripping means.
According to the present invention, there is provided an apparatus for treating a tail yarn in a textile spindle assembly having an upper slit ring fixedly mounted on a base portion of a spindle, a cylindrical member having a lower slit ring at an upper end thereof and a lower portion outwardly expandable by centrifugal force of the spindle, and a guiding surface fixed on a lower part of said base portion of the spindle, said cylindrical member being axially slidably fitted on said base portion of the spindle beneath said upper slit ring and mounted so that a lower end of the expandable portion thereof capably come into contact with said guiding surface, said upper slit ring and said lower slit ring being pressed together to form a tail yarn gripping means, whereby expansion of said lower portion of said cylindrical member by centrifugal force causes said cylindrical member to slide axially downward to release a pressed state between said upper slit ring and said lower slit ring, characterized by further comprising a spring member for positively restoring said lower portion of said cylindrical member from an expanded state to an initial state upon standstill of the spindle, said lower portion of said cylindrical member being split by a plurality of slits.
As this spring member, there may be used a ring-like spring fitted around a periphery of the lower portion of the cylindrical member or a leaf spring attached to the lower portion of the cylindrical member. In order to make it easy to remove the yarn underwindings and improve the effect of fixing the tail yarn (interconnecting yarn) to the tail yarn gripping means, a predetermined number of grooves may be radially outwardly formed on an upper surface of this lower slit ring.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional side view showing an embodiment of the present invention;
FIGS. 2 and 3 are side views showing cylindrical members which may be used in the present invention;
FIGS. 4 to 8 are side views, partly in cross sections, for illustrating operation of an apparatus of the present invention;
FIG. 9 is a side view, partly in cross section, showing another cylindrical member which may be used in the present invention; and
FIG. 10 is a plan view showing another embodiment of the cylindrical member shown in FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Apparatus of the present invention will hereinafter be described according to the drawings.
FIG. 1 is a sectional side view showing an embodiment of the present invention. A cutter holder 4 provided with a cutter 3 is securely fixed on an upper part of a base portion of a spindle 2 on which a bobbin 1 is mounted. In this embodiment, the cutter holder 4 is used as an upper slit ring 5. However, a separate upper slit ring 5 may be securely fixed under the cutter holder 4. A cylindrical member 8 having a lower slit ring 6 at an upper end thereof and a lower portion 7 outwardly expandable by centrifugal force is axially slidably fitted on the base portion 2 of the spindle beneath the upper slit ring 5 (cutter holder 4).
The cylindrical member 8 is mounted so that a lower end 9 of the expandable portion (lower portion) 7 thereof capably comes into contact with a guiding surface 10' fixed on the base portion 2 of the spindle. The upper slit ring 5 (cutter holder 4) and the lower slit ring 6 are pressed together to form a tail yarn gripping means 11. When the spindle rotates and the lower portion 7 of the cylindrical member 8 is outwardly expanded by the centrifugal force of the spindle, the lower end 9 comes into contact with the stationary guiding surface 10, which causes the cylindrical member 8 to slide axially downward (in the direction shown by arrow A) to release a pressed state between the upper slit ring 5 and the lower slit ring 6. The mark Y designates a yarn to be wound on the bobbin 1, the numeral 12 designates an interconnecting yarn formed between the tail yarn gripping means 11 and the bobbin 1, the numeral 12' designates a tail yarn corresponding to the interconnecting yarn 12 after separated (see FIGS. 7 and 8), the numeral 16 designates a ring-like coil spring fitted in a groove 17 formed around a periphery of the lower end 9 of the lower portion 7 of the cylindrical member 8, and the numeral 18 designates a cover.
As shown in FIGS. 2 and 3, the upper end of the cylindrical member 8 constitutes the lower slit ring 6 and the lower portion 7 thereof is split by a plurality of slits 13 so as to be outwardly expanded by centrifugal force. The lower end 9 of the lower portion 7 is not limited to a polygonal shape as shown in FIGS. 2 and 3, but may have any shape such as a circular or a elliptic shape.
The cylindrical member 8 may be composed of any material such as metal or plastic, as long as the lower portion 7 and the lower end 9 thereof are outwardly expandable by centrifugal force.
The groove 17 is formed around the periphery of the lower end 9 of the lower portion 7 of the cylindrical member 8, and the ring-like coil spring 16 is fitted in the groove 17 so that the lower portion 7 of the cylindrical member 8 and the lower end 9 thereof are positively restored from an expanded state to an initial state upon standstill of the spindle (see FIG. 2). In place of the ring-like coil spring, a leaf spring 16' may be embedded in or stuck on the lower portion 7 of the cylindrical member 8 as shown in FIG. 3. Any type and any shape of spring may be used, as long as the lower portion 7 of the cylindrical member 8 and the lower end 9 thereof can be positively restored from the expanded state to the initial state when the spindle is stopped and thereby centrifugal force comes not to be exerted.
By suitable selection of the force of the springs 16 and 16', the material of the cylindrical member 8, the thickness of the lower portion 7, the number and the shape of the slits 13 and the like, the cylindrical member 8 can be slided downward at a desired spindle revolution, and thereby the pressed state between the upper slit ring 5 and the lower slit ring 6 can be released.
The cover 18 is provided for the purpose of preventing floating cottony substances from entering the stationary guide during operation, when the cylindrical member 8 is lowered by the rotational centrifugal force of the spindle and the yarn underwindings are released and removed from the tail yarn gripping means, which cover may be formed integrally with the lower slit ring 6.
One of peripheral end portions of both the slit rings 5 and 6 may be flat, instead of the expanded form shown in the drawings.
Then, the operation of the apparatus of the present invention, when the apparatus shown in FIG. 1 is used, will hereinafter be described in accordance with FIGS. 4 to 8.
In FIGS. 4 to 8, the same parts as in FIG. 1 are designated by the same numerals as in FIG. 1, and the descriptions thereof are omitted.
FIG. 4 shows a state just before the start of winding on the bobbin 1 in the textile spindle assembly of the spinning machine, wherein the cylindrical member 8 is pressed upward and the lower slit ring 6 is pressed to the upper slit ring 5 to form the tail yarn gripping means 11.
A yarn Y fed from the roller part (not shown in the drawings) of the spinning machine is passed through the traveler 15 fitted on the traverse ring 14 and held to the tail yarn gripping means 11 by wrapping its end about half to one turn thereon.
Then, on the start of winding, the traverse ring 14 is raised to the winding position of the bobbin 1 as shown in FIG. 5, and the interconnecting yarn is formed between the tail yarn gripping means and the bobbin 1. The ring rail 15 and the traverse ring 14 reciprocate within the yarn winding range of the bobbin 1 to start the winding of the yarn Y on the bobbin 1 as shown in FIG. 6. Subsequently, when the rotation of the spindle 2 is increased to a predetermined rotation speed, the lower portion 7 of the cylindrical member 8 is outwardly expanded by centrifugal force, as shown in FIG. 7, as a result, the lower end 9 comes into contact with the stationary guiding surface 10.
Thereupon, the movement of the lower end 9 is restricted by the stationary guiding surface 10. Hence, further addition of centrifugal force lowers the cylindrical member 8 automatically downward (in the direction of the arrow A). Thus, the interconnecting yarn 12 which has been held with the tail yarn gripping means 11 is released for removal from the tail yarn gripping means 11 by the rotational centrifugal force of the spindle 2 to form the tail yarn 12'.
In this case, the upper end of the stationary guide closely comes into contact with the lower surface of the lower slit ring 6 inside the cover 18, which covers the stationary guide. It does not therefore happen that floating cottony substances enter the stationary guide.
When the yarn package building on the bobbin 1 is completed, the ring rail 15 and the traverse ring 14 are rapidly lowered again to the position corresponding to the tail yarn gripping means 11 as shown in FIG. 8, and the tail yarn is held by wrapping less than 1 turn around the tail yarn gripping means 11. Then, the spindle is stopped. In this case, the previous tail yarn 12' has been completely released for removal from the tail yarn gripping means 11, and the lower portion 7 of the cylindrical member 8 has positively returned from the expanded state to the initial state by the force of the spring 16, with a decrease in rotation speed of the spindle 2. Consequently, the lower end 9 has come into contact with the lower stationary guiding surface 10' to press the cylindrical member 8 upward, and thereby the tail yarn gripping means 11 has returned to the pressed state. Hence, the end of the yarn Y which has been completely wound is very firmly held with the tail yarn gripping means 11.
After the rotation of the spindle is terminated, the completed yarn package is pulled up with an auto-doffer.
At that moment, the interconnecting yarn 12 of the yarn Y formed when the traverse ring 14 lowered to the position corresponding to the tail yarn gripping means 11 is pressed onto the cutter 3 in its stretched condition to separate the interconnecting yarn 12. By repetition of the procedures described above, the doffing operation can be automatically achieved.
When a textile spinning machine, a twister or the like provided with the tail yarn treating apparatus of the present invention is newly installed, or when the base portions of the spindles in a prior-art textile spinning machine, a prior-art twister or the like are changed to the tail yarn treating apparatus of the present invention, the wrapping number of the tail yarn around the tail yarn gripping means 11 is gradually adjusted to less than 1 turn so that the yarn underwindings (not shown in the drawings) which are the residual yarns of the previous separated tail yarn 12' remaining in the tail yarn gripping means 11 are automatically released, prior to the production operation.
In this stage, if the grooves 19 are radially outwardly formed on the upper surface of the lower slit ring 6 as shown in FIGS. 9 and 10, the yarn underwindings not released from the tail yarn gripping means 11 can be removed by sliding a hook-like tool having a hook-shaped tip (not shown in the drawings) along the grooves 19 radially formed.
Moreover, the tail yarn of the yarn Y is engaged with upper edge portions 19' of the grooves 19 radially formed, and therefore the effect of fixing the tail yarn to the tail yarn gripping means 11 is further improved.
Further, any number of grooves 19 radially formed may be used without limitation, though 3 grooves are formed in this embodiment. Usually, 2 to 6 grooves are suitable.
In FIGS. 9 and 10, the lower slit ring 6 and the cover 18 are formed as an integral body.
According to the present invention, the lower portion of the cylindrical member is not reduced in restoring force from the expanded state even if used for a long period of time and can be positively restored from the expanded state to the initial state. Further, the tail yarn can be securely held and the doffing operation can be automatically carried out without failure.
A predetermined number of grooves radially outwardly formed on the upper surface of the lower slit ring make the removal of the yarn underwindings easy and can improve the effect of fixing the tail yarn to the tail yarn gripping means. | Disclosed is an apparatus for treating tail yarns in textile spindle assemblies of textile spinning machines, twisters, etc., wherein a stationary upper slit ring and an axially slidable cylindrical member having a lower slit ring at an upper end thereof and a lower portion outwardly expandable by centrifugal force and provided with a spring are mounted on a base portion of a spindle to form a tail yarn gripping means, the pressed state of which is released by sliding the cylindrical member downward by rotational centrifugal force, whereby the yarn underwindings can be automatically removed from the tail yarn gripping means during operation.
Further, not only the elasticity of the cylindrical member itself but also the force of the spring is utilized for restoring the lower portion of the cylindrical member from the expanded state to the initial state, and hence the lower portion of the cylindrical member is surely positively restored to the initial state, whereby the tail yarn is surely firmly fixed to the tail yarn gripping means. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for cleaning gaskets, glues or the like from between piping system flanges, in situations wherein it is desirable or possible to separate the flanges by only a very small width.
2. Description of the Prior Art
A common problem in piping systems is the necessity of cleaning an old gasket and accompanying adhesive from between two flanges. Thorough cleaning in such a situation is essential, as any waste left in place may interfere with the proper attachment of a replacement gasket. An incomplete cleaning can result in a reassembled joint that leaks in service, and therefore costly losses will occur, especially if part or all of a system has to be shut down to correct the leak.
The traditional method for detaching old gaskets and the like in situ, wherein it is generally desirable, and sometimes required, to separate two flanges by only a very small gap, is time-consuming and often the results are unsatisfactory. For instance, wedges are driven between the flanges to spread them apart, and a hacksaw or similar thin blade is inserted into the gap to scrape away at the matter needing to be removed. The unsystematic nature of the process increases the chance that a spot of waste will go unnoticed--until the piping involved is put back into service. Furthermore, the cramped quarters in which this task must often be accomplished add to the burden of the process and increase the likelihood of an imperfect cleaning.
To remedy this problem, it is desirable and not previously known to have a specialized tool that can efficiently clean gasket material and the like from flange surfaces in an awkward environment.
Numerous patents have issued for cleaning tools of various types. In particular, there are a number for cleaning tools that use a rotating motion to scrape or otherwise clean a surface. For example, U.S. Pat. No. 2,706,304, issued to Harry Demory on Apr. 19, 1955, discloses a rotary-type scraper for use in cleaning meat blocks. Japanese patent No. 404,085,465, issued to Kunibagumi K. K. on Mar. 26, 1990, concerns a device for scraping and collecting asbestos and incorporates rotating cleaning parts. A linoleum cutter with cutting bars radially arrayed on a rotating disk is discussed in U.S. Pat. No. 2,738,966, issued to Lyle Davis on Mar. 20, 1956. U.S. Pat. No. 4,531,253, issued to Spencer D. Cottam on Jul. 30, 1985, teaches the use of a rotating disk bearing a plurality of bent wires for cleaning surfaces. U.S. Pat. No. 1,387,027, issued to Isaac A. Latrous on Aug. 9, 1921, shows a rotary scraper with spring arms.
Rotating scrapers that further include removable blades are also generally known. Examples of such devices are shown in U.S. Pat. No. 2,48,739, issued to Franklin D. Johnson on Aug. 3, 1949; U.S. Pat. No. 3,216,41, issued to Horace R. Walters on Nov. 9, 1965; and U.S. Pat. No. 3,613,147, issued to Oct. 19, 1971.
Some existing scraper tools possess a ratcheting ability. U.S. Pat. No. 4,255,828, issued to Dan P. Colla on Mar. 17, 1981, and U.S. Pat. No. 5,235,719, issued to Leon Wimberley on Aug. 17, 1993, disclose such tools.
Other clearing or cleaning tools are described in U.S. Pat. No. 3,091,791, issued to Frank Czapar, Jr. on Jun. 4, 1963, and Swedish Patent No. 222,007, issued on Aug. 6, 1968.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
The present invention concerns an improved tool for cleaning facing flange surfaces in cramped quarters. The tool includes two cleaning disks which attach to an actuating element that includes an actuating disk and handle. The cleaning disks are retained against the actuating disk by a hub and bushing arrangement that extends through central circular apertures in the disks. The hub may permanently retain the components, or the mounting may be temporary in nature. Cleaning elements are arranged radially on the cleaning disks, interspersed with hollow debris ports for receiving debris.
The cleaning elements may be integral to the cleaning disks, or may be detachably attachable. A variety of cleaning elements are available, among them file, razor, and rasp blades.
In an alternative embodiment, the tool may comprise a unitary configuration, there being a blade portion having surface cleaning structure on one or both faces, and a handle. The handle is coextensive with the blade, so that neither the blade nor the handle has a projecting edge, relative to the other, which could interfere with a flange as the tool is inserted between flanges. A hole is formed in the blade portion, so that a bolt or similar fastener holding the flanges abutted is reinstalled, passing through the hole, and serves as a pivot enabling the tool to be moved through an arc, cleaning one or both flanges with each pass. A wedge configured as a sleeve fitting closely but slidably over the handle can be forced toward the axis of the pipe being serviced, to assist in separating the two flanges.
In use, a pair of flanges to be cleaned are separated such that the tool, which is very thin, can be inserted between them in a concentric configuration. The flanges are retightened so that the cleaning elements, on the outer surfaces of the tool, are against the flanges. In refastening the flanges, a sufficient number of the fasteners--which may be, for instance, bolts--are left out so that there is ample arc room for the tool to be used most efficiently. A suggested arrangement is to leave a 120 degree portion free.
In the primary embodiment, the tool is ratcheted forward and released backward through the free arc manually or by way of a motor attachment. The cleaning elements chosen at a given time obviously depend on the particular stage of cleaning involved. In any case, a large proportion of the fragments dislodged by the cleaning elements move into the proximate debris ports and/or progress to the outside of the tool, thus allowing tool use to continue for a substantial time.
Accordingly, it is a principal object of the invention to provide a tool for efficiently and systematically cleaning the facing surfaces of flanges in piping systems.
It is another object of the invention to provide a flange-cleaning tool incorporating a ratchet mechanism.
It is a further object of the invention to provide a flange-cleaning tool that can be used comfortably in cramped conditions.
It is yet another object of the invention to provide a flange-cleaning tool that includes a central actuating disk with handle and two attached cleaning disks.
It is an object of the invention to provide a flange-cleaning tool with a wide range of detachably attachable cleaning elements.
Still another object of the invention is to provide a flange-cleaning tool with auxiliary devices for extra leverage.
Another object of the invention is to provide a flange-cleaning tool that can be powered either manually or by motor.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is an exploded perspective view of a flange-cleaning tool according to the present invention.
FIG. 1B is a detail view of the cleaning element of the present invention.
FIG. 1C is a detail view of another embodiment of the cleaning element.
FIG. 2 is an environmental side view of the present invention.
FIG. 3 is an environmental front view of the cleaning piece of the present invention.
FIG. 4 is a partial environmental view of the present invention.
FIG. 5 is a detail view of an embodiment of the handle area of the present invention.
FIG. 6 is a detail view of another embodiment of the handle area.
Similar reference characters denote corresponding features consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1A, the present invention is a flange-cleaning tool, generally designated 10, which is particularly adapted for use in cleaning piping system flange pairs on location. Waste needing to be cleaned from flange pairs 11, 13, shown in FIG. 2, typically includes old gaskets, often delaminated, adhesives, and the like. In such situations, the surroundings are often cramped, which adds to the awkwardness of the use of traditional flange-cleaning methods. Generally, these methods involve driving wedges between flanges 11, 13 to spread their facing surfaces 15, 17 enough to allow the insertion of scraping devices, or employing a spreading tool, as is well known in the industry. The scraping devices may include hacksaw blades or similar thin blades, which are wielded manually. Thinness of the tool is frequently critical, since piping systems may have little play, and frequently resist significant spreading of flanges. Thus, even a spreading tool designed for this situation may prove ineffective.
Even when this process of scraping is carried out carefully it is not unusual, due to the cramped working conditions and inherently unsystematic nature of the process, for some material to be missed. Such leftover material can interfere with the seal of any new gasket installed. The resulting joint leak may necessitate closing down part or all of the involved piping system for a rework. In contrast, the instant flange-cleaning tool handles the task of cleaning facing flange surfaces in a systematic and efficient manner.
FIG. 1A shows the primary embodiment of the tool in exploded form, while FIG. 2 shows it in assembled form and in use. An actuating element 12 includes a handle 14 and a main component 16, with the main component 16 having a first inner perimeter 18 surrounding a circular aperture 20. The main component 16 is shown in all figures as an actuating disk 22, but it is obvious that it could take on other shapes. The actuating disk 22 and handle 14 are integral and coplanar. Coplanar is used here to mean that the handle 14 and actuating disk 22 are of similar thickness and lie in the same plane, forming an essentially flat surface. In order to allow for insertion within a very small gap between flanges, as is shown in FIG. 2, the actuating disk 22 can be made very thin. It is envisioned that the total thickness of the flange-cleaning tool 10 may be as little as 3/8th of an inch, with the thickness of the actuating disk 22 being in the neighborhood of 1/8th of an inch. Of course, other dimension values are possible. The preferred material is a high-quality spring steel, or equivalent, that provides maximum rigidity and allows stringent thinness.
In use, the flange-cleaning tool 10 is moved by the handle 14 of the actuating element 12, with the actuating element 12 thus imparting an input motion to the tool 10. In the embodiments shown in the figures, the tool 10 further includes two cleaning pieces 24, 26, which are also very thin and which include second inner perimeters 28, 30. The cleaning pieces 24, 26 are attached laterally to the actuating element 12, sandwiching the main component 16. The cleaning pieces 24, 26 are preferably configured as cleaning disks 24, 26, of the same diameter as the actuating disk 22. As with the main component 16, other shapes are possible. It is also possible, for instance when greater thinness is desired, to use only one cleaning piece 24. However, the presence in the primary embodiment of the described two simultaneously usable opposed cleaning surfaces, of the cleaning disks 24, 26, speeds cleaning in situations that allow the entrance of a flange-cleaning tool 10 with the greater thickness.
These cleaning disks 24, 26 are one form of rotating cleaning means. It is also possible, though not shown, to have rotating cleaning means integral to the actuating element 12.
Securement of the cleaning disks 24, 26 to the actuating element 12 is effected with retaining means 32. Shown in FIG. 1 are a hub 34 and a bushing 36. The hub 34 and bushing 36 are dimensioned and configured to fit tightly within the first inner perimeter 18 and the second inner perimeters 28, 30. The hub 34 has two ends, a first end 38 and a second end 40. Connected to each of the ends 38, 40 is a retaining lip 42. Only one restraining lip 42 is shown in FIG. 1A, in order to suggest a possible pre-assembly configuration. The retaining lip 42, which may be permanent or temporary, may be configured in a variety of ways. It may be manufactured as an integral part of the hub 34, or it may be welded on after insertion into the tool 10. Alternatively, retaining lip 42 may be formed by rolling or pressing of the hub 42 after insertion.
The bushing 36, made of soft metal or another low-friction material, rests between the hub 34 and the first and second inner perimeters 18, 28, 30. It may be cylindrical, of a washer-type shape, or of any other useful configuration.
The union of the actuating element 12 and the cleaning disks 24, 26 is effected in order to make possible the use of a ratchet mechanism 44. The actuating element 12 includes a driving ratchet mechanism 46, which is configured to fit complementarily with a driven ratchet mechanism 48 included in each of the cleaning disks 24, 26. The ratchet mechanism 44 is of any of the types well-known in the art. For instance, in the primary embodiment three controlling ratcheting teeth 50, 52, 54 are provided along the a first outer perimeter 56 of the actuating disk 22, while a second outer perimeter 58 of each of the cleaning disks 24, 26 is configured to provide a plurality of receiving ratcheting teeth 60. The three controlling ratcheting teeth 50, 52, 54 are fixed at equal arc distances to provide even torque to the cleaning disks 24 26 and to provide three even support points for the lateral force applied to the flange surface. Thus, the tool 10 is protected from the threat of warping or bowing under stain. Alternatively, ratchet teeth may be located radially, proximate to the first and second inner perimeters 18, 28, 30.
It is also possible to dispense with the ratchet mechanism 44. For instance, the embodiment described above in which the rotating cleaning means is integral to the actuating element, dispensing of the cleaning disks, could operate without a ratchet mechanism 44.
Actual cleaning of flange surfaces 15, 17 is accomplished by a plurality of cleaning elements 62, which in the primary embodiments are included in the cleaning pieces 24, 26. In alternative embodiments in which the rotating cleaning means are integral to the actuating element 12, the cleaning elements 62 are clearly part of the actuating element 12. By cleaning elements 62 it is meant any of a variety of tools useful to the cleaning of waste. Cleaning elements 62 have surfaces suitable for cleaning a flange. For example, radially oriented, axially projecting cutting blades may be formed in or attached to a disk 24 or 26, for removing large pieces of gasket. Disk 24 or 26 may have a rigid or resilient wiping blade for removing minor leakage residue or dust from a previous cleaning operation. In a further example, disk 24 or 26 may include an abrasive lining, as by coating with abrasive grit, for resurfacing the metal face of the flange. Known tools which may be adapted for use in the present invention, therefore, may include razor, rasp, file, and sandpaper blades, among others.
The cleaning elements 62 may be permanently or detachably attached to the tool 10. Axial surfaces of tool 10 rubbing against flanges are preferably treated to impart low friction characteristics thereto. These surfaces may be highly polished, or coated with a substance such as polytetrafluoroethylene. This treatement will help compensate for friction generated by the cleaning surface with the flange.
FIG. 1A shows a primary arrangement for detachably attached cleaning elements 62, with only two cleaning elements 64, 66 displayed. Cleaning element 64 or 66 includes a body 68 and an implement 70. In this embodiment, implement 70, an indeterminate blade, is a permanent part of cleaning element 64. In other embodiments, such as that shown in the detail view of FIG. 1B, an implement 72 may be detachably attached to a body 68 by fasteners 74, 76.
Generally, in cases of detachably attachable cleaning elements, each cleaning element 62 is provided with detent-type release devices 78, 80. The release devices 78, 80 are complementary with a tooth 82 integral to an element site 84 of the cleaning disk 24. Thus, a cleaning element 62 can be replaced at will by snapping out one in use and replacing it with a different one. In another embodiment, shown at one element site 84 in FIG. 4, an entire cleaning element 62 is secured to the cleaning disk by screws or similar fasteners.
As shown, the body 68 projects through the element site 84 with a reinforcing tab 90. When the tool 10 is assembled and in use, the reinforcing tab 90 bears against the actuating disk 22 and provides reinforcement for the cleaning element 62.
Next to each element site 84 is a debris aperture 92. In use, some of the waste or debris from the facing flange surfaces 15, 17 being cleaned will be pushed into the debris aperture 92, thus lengthening the amount of cleaning a user can do without having to clean off the flange-cleaning tool 10. Some debris will also exit from the sides of the flange-cleaning tool 10.
The tool 10 may include an additional leverage device 94. For instance, shown in FIG. 4 is a bar 96, attachable to the handle 14 by a typical fastener arrangement 98 that secures through a circular aperture 100. Shown in FIG. 5 is a T-housing 102, which also attaches to the handle 14. Other configurations of leverage devices are possible.
Another embodiment of the tool 10, shown in FIG. 6, provides the handle 14 with a reinforcing lip 104. The reinforcing lip 104 is particularly useful if a difficult cleaning situation makes it desirable to hammer upon the handle 14 to help it move.
In use, the tool 10 may be powered manually or by mechanical driving means. Versions of both options are shown in FIG. 4. A motor 106 turns a crank arrangement 108, which in turn moves the handle 14 of the tool 10 back and forth.
The methods of use of the flange-cleaning tool 10 have been implied in the figures and above discussion. A general summary of use may begin with securing a pair of flanges 11, 13 to a distance sufficient to allow the insertion of the tool 10. If, as is common, the flanges 11, 13 are held together by bolts, then, for instance, it may be necessary to remove the bolts entirely from bolt holes 110, 112, 120, while loosening the bolts in holes 114, 116, and 118 to allow a minimum gap, slightly greater than the thickness of the tool 10, to form.
The flange-cleaning tool 10, which must have a radius 120 smaller than the radial distance 122 from the center 124 of a flange 11 to a bolt hole 110 (or 112, 114, 116, 118, or 120), is inserted between the pair of flanges 11, 13. The centerpoint 126 of the tool 10 is lined up with the centerpoints 124, 128 of the flanges 11, 13.
The bolts in bolt holes 114,116, and 118 may be tightened, if desired, to bring the cleaning elements 62 on both cleaning disks 24, 26 into contact with the inner flange surfaces 15, 17. Bolts may also be inserted back into bolt holes 110, 112, 120 and similarly tightened, or some or all of bolt holes 110, 112 and 120 may be left empty. The user is advised to balance the advantages of an even distribution of support points against the value of a streamlined tightening process and freedom of movement of the tool 10. Once the tightening process has been finished, the tool 10 is ready for use.
In use, the tool 10 is moved so that the implements 70 of the cleaning disks 24, 26 contact and clean, as by scraping, wiping, or abrading, the inner flange surfaces 15, 17. Movement is generally by partial rotation, or oscillation, when, for instance, the flanges 11, 13 are secured by bolts in some or all of bolt holes 110, 112, 114, 116, 118, 120. As implied above, it is likely that the user will wish to leave some bolt holes empty in order to allow a wide arc of movement for the tool 10.
In situations where the flanges are tightened together by means that do not include through-extending fasteners such as bolts, it may be possible to fully rotate the flange-cleaning tool 10.
It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. | A flange-cleaning tool unites an actuating disk and integral handle with two cleaning disks in a primary embodiment. Union is achieved with a hub and bushing, both fitted through central circular apertures in the disks. The outward-facing sides of the cleaning disks are lined radially with cleaning elements, which may be, for instance, of the razor, rasp, or sandpaper type. Interspersed with the cleaning elements are debris apertures. The tool is manually or motor-powered, and incorporates a circumferential ratcheting mechanism in the primary embodiment. In a secondary embodiment, the ratcheting mechanism is located radially. Auxiliary devices may be attached for extra leverage, and a reinforcing lip on the handle makes it possible to safely apply a high impact force in difficult cleaning situations. | 5 |
BACKGROUND OF THE INVENTION
There is a need to determine when a train vehicle operative in an automated vehicle control system is moving at zero speed or at less than a predetermined zero equivalent speed, with a fail-safe or vital zero speed indication signal being provided as desired for train operation control purposes when the train vehicle is moving at less than such predetermined zero speed. A propulsion enable signal is provided when the actual speed of the train vehicle is less than the desired speed for that vehicle. When the actual speed of the vehicle is greater than the desired speed the propulsion enable signal is not provided and the full service brake will be applied. In addition when the train vehicle is detected to be positioned adjacent to a station platform, a door open enable signal is provided when the vehicle is sensed to be moving at less than a predetermined zero equivalent speed such as 0.1 mile per hour. The provision of the propulsion enable signal and the provision of the door open enable signal has to be in a substantially fail-safe manner.
The train vehicle has to be out of a full service brake condition of operation to move the train in response to a desired speed signal. In normal operation the train can be operating along a track divided into signaling blocks of respective predetermined lengths, with a very low impedance connection being made between the track rails at the ends of each such signal block. A signal transmitter is operative with one end of each signal block at one of several frequencies and a cooperative signal receiver is coupled with the other end of each signal block for controlling the operation of a train vehicle positioned within that signal block, such as described in U.S. Pat. No. Re. 27,472 and U.S. Pat. No. 3,532,877 of G. M. Thorne-Booth and in U.S. Pat. No. 3,593,022 of G. M. Thorne-Booth et al. A published article entitled "Automatic Train Control Concepts Are Implemented By Modern Equipment" by R. C. Hoyler in the September 1972 Westinghouse Engineer at pages 145 to 151 includes a disclosure of this operation.
A signal receiver carried by the train vehicle senses a desired speed coded signal from the signal block occupied by that vehicle, which desired speed signal the train decodes and provides a desired speed command signal to the propulsion control apparatus of the train vehicle to result in energizing the propulsion motors for regulating the actual speed to correspond with the desired speed of operation along the track and within a particular signal block. The actual speed of the vehicle is obtained from a pair of tachometers operative with the wheels of the vehicle as disclosed in U.S. Pat. No. 3,810,681 of T. C. Matty. If the actual speed of the train vehicle is too low, more propulsion effort for the vehicle is required and if the actual speed is too high then braking of the vehicle is provided.
SUMMARY OF THE INVENTION
According to the teachings of the present invention a train control apparatus is provided for sensing a zero speed condition of a train vehicle, with any sensing failure being detectable and not yielding a false zero speed indication. A pair of speed sensing tachometers are operative with the controlled train vehicle. When both tachometers are dynamic, with the vehicle moving, the outputs of the tachometers are established to be true and a vital or fail-safe propulsion enable signal permits the vehicle to continue moving. When both tachometers are static, the outputs of the tachometers are established to be static and the zero speed indication signal is provided. The train vehicle includes a door open control apparatus responsive to the zero speed indication signal to inhibit the vehicle doors from opening when the vehicle is moving faster than the predetermined equivalent zero speed. The train vehicle includes a propulsion and brake control apparatus responsive to the propulsion enable signal for removing the full service brake and to permit the vehicle propulsion motor to be energized when the desired speed of the vehicle is greater than the actual speed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic showing of a well-known track signal block arrangement operative with a train vehicle to be controlled;
FIG. 2 is a schematic showing of a train vehicle control system, including signal integrity apparatus of the present invention;
FIG. 3 is a graphical showing of vehicle operational speed relationships;
FIG. 4 is a schematic showing of the present signal integrity apparatus;
FIG. 5 illustrates the respective tachometer apparatus output signals;
FIG. 6 is a schematic showing of prior art train vehicle braking control apparatus; and
FIG. 7 is a schematic showing of the switching circuits included in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 there is shown a well-known track arrangement including rails 10 and 12 along which a train vehicle 14 moves in the direction indicated by the arrow. The train vehicle 14 includes speed signal receiving antenna 16 which is positioned above the rails and ahead of the front wheels. The track is shown divided into signal blocks N-1, N, N+1 and N+2 by low impedance members connected between the two rails 10 and 12 at the respective ends of each signal block. Each signal block is energized with a desired speed signal, such as signal block N receives a speed signal from transmitter T N coded in accordance with the desired speed for vehicle 14 traveling within the signal block N. A receiver R N is operative with the signal block N in relation to the determination by wayside equipment of the occupancy of signal block N by a train vehicle, for the purpose of controlling the entry of a subsequent train vehicle in relation to an already occupied signal block. The desired speed signal supplied to signal block N by the transmitter T N represents the maximum desired speed for the passage of a train vehicle through the signal block N.
In FIG. 2 there is shown the antenna 16 which is located on the vehicle and supplies the desired speed signal to the speed signal receiver and decoder 18 operative to filter, amplify, limit, demodulate and decode the desired speed signal in the signal block occupied by the train vehicle to be controlled. The desired speed is compared to the actual speed in a speed regulation and overspeed protection apparatus 20, with the actual speed being obtained from two tachometers 22 and 24 operative with an axle 25 of the train vehicle. If the actual speed is too low, additional propulsion effort is required. If the actual speed is too high, then braking of the vehicle is required. A vital NOT overspeed signal 26 is provided by the speed regulation and overspeed protection apparatus 20. As long as the actual speed of the vehicle is less than the desired speed, the signal 26 enables the propulsion motor to be energized for moving the vehicle along the track. If the actual speed becomes greater than the desired speed, the signal 26 causes the full service braking operation to occur. It should be understood that a suitable signal deadband can be included within which undesirable repetitive cycling between propulsion and braking is avoided. The signal 26 is supplied to a signal integrity apparatus 28 in which the NOT overspeed signal 26 is combined with the respective tachometer output signals 30 and 32 in a logic AND operation to provide a propulsion enable signal 34 in accordance with the NOT overspeed and the tachometer integrity functions. If one of the tachometers 22 or 24 should fail, the propulsion enable signal 34 is discontinued and this operates with the propulsion and braking control apparatus 36 to apply the full service brake for stopping the train vehicle.
A door open enable signal 38 is provided by the signal integrity apparatus 28 when the tachometers 22 and 24 indicate the vehicle axle speed is less than a predetermined equivalent zero speed. This door open enable signal 38 is supplied to door control apparatus 40 and operative in conjunction with the signal 42 from a station stop transmitter 44 when the train vehicle is positioned adjacent a station platform suitable for the loading and unloading of passengers.
In FIG. 3 the curve 50 shows an illustrative desired speed for a train vehicle passing through a signal block N and the next adjacent signal block N+1. With the actual speed of a train vehicle operating in signal block N following the curve 52 slightly below the desired speed curve 50, and the average actual speed of the vehicle could be in accordance with curve 54. When the vehicle leaves signal block N and enters the next adjacent signal block N+1 having a reduced desired speed as shown by curve 50, the full service brake of the vehicle will be applied to slow down the vehicle as generally shown in FIG. 3 in relation to actual speed curve 52. Where the actual speed curve 52 is below the desired speed curve 50 the NOT overspeed signal 26 and the propulsion enable signal 34 would be provided and the propulsion motor of the vehicle would function to move the vehicle along the track. When the actual speed as shown by curve 52 is above the desired speed as shown by curve 50, the full service brake operation would occur, with the consideration as well known in this art that passenger comfort would be maintained in this regard.
In FIG. 4 there is schematically shown the signal integrity apparatus 28 of FIG. 2. The NOT overspeed signal 26 is applied through AND gates 60 and 62, which AND gates are in accordance with the disclosure of U.S. Pat. No. 3,600,604 of G. M. Thorne-Booth. The gates 60 and 62 will pass the NOT overspeed signal 26 and provide the propulsion enable signal 34 when the control signals 61 and 63 respectively are negative in relation to a reference voltage. The similar gates 64 and 66 will pass the carrier signal 68 from the signal source 70 and provide the door open enable signal 38 when the control signals 61 and 63 respectively are positive in relation to reference voltage. The tachometer 22 is operative with a switching apparatus 72 for applying a control signal 63 to each of the gates 62 and 66. The tachometer 24 is operative with a switching apparatus 74 for applying a control signal 61 to each of the gates 60 and 64. The control signal 63 from switching apparatus 72 cannot simultaneously be positive and negative, and therefore an effective exclusive OR logic function is provided in conjunction with the gates 62 and 66, and the same functional operation applies for the control signal 61 from the switching apparatus 74 in conjunction with the gates 60 and 64. Both of the control signals 61 and 63 have to be negative to provide a signal path from the NOT overspeed signal 26 through the gates 60 and 62 to output the propulsion enable signal 34. Both of the control signals 61 and 63 have to be positive to provide a signal path from the carrier signal source 70 through the gates 64 and 66 to output the door open enable signal 38. At no time can signal paths be simultaneously provided respectively through the gates 60 and 62 for signal 34 and through the gates 64 and 66 for signal 38. When the control signal 61 is different than the control signal 63, with one positive and the other negative, neither of the output signals 34 and 38 will be provided at that time.
The tachometers 22 and 24 are operative with the same vehicle axle for maintaining a desired phase relationship between their respective output signals 30 and 32 as disclosed in U.S. Pat. No. 3,810,681 of T. C. Matty. The signal 30 and the signal 32 can only be negative if the associated tachometer is dynamic and properly phased in relation to the dynamic second tachometer, and any operational failure either in the associated switching apparatus, physically in each tachometer or in the relative phasing of the two tachometers will result in signal 61 and signal 63 not being negative. With the train vehicle moving in the forward direction a predetermined phase relationship, for example leading, is provided and sensed by the signal integrity apparatus 28 shown in FIG. 4.
In FIG. 5 there are shown signal waveforms to illustrate the output signals from the tachometers 22 and 24 and the switching circuits 72 and 74. The curve 5a shows the sinusoidal waveform of signal 30 from the variable reluctance tachometer 22. The curve 5b shows the square waveform of signal 63 from the schmidt trigger switching circuit 72. The curve 5c shows the 90° phase shifted sinusoidal waveform of signal 32 from the variable reluctance tachometer 24 and the curve 5d shows the square waveform of signal 61 from the schmidt trigger switching circuit 74.
In FIG. 6 there is shown the vehicle movement sensing apparatus disclosed in U.S. Pat. No. 3,810,681 of T. C. Matty. The square wave signal 84 from the tachometer 86, which can include a square wave generating switching circuit, is 90° in phase ahead of the square wave signal 88 from the tachometer 90 for a forward direction movement of the train vehicle. When the signal 84 from tachometer 86 becomes positive, the transistor 82 becomes conducting but the transistor 80 is still not conducting, and therefore no current path is provided from the source +V to ground through the primary winding 92 of the transformer 94. Thusly, the detector circuit 96 detects no signal and provides a zero volt signal to the AND gate 98 such that the AND gate 98 does not provide a path for a signal from oscillator 100 to be applied to the propulsion control 102. In addition the detector circuit 104 senses no signal from transistor 106 and provides a zero volt signal to the AND gate 108 which does not provide a path through the AND gate 108 to provide a signal from the oscillator 100 to the propulsion control 102. The AND gates 98 and 108 are in accordance with the disclosure of U.S. Pat. No. 3,600,604 of G. M. Thorne-Booth, where a negative signal is required to enable the AND gate to pass the periodic signal from the oscillator 100 to the propulsion control 102.
When the signal 88 from the tachometer 90 becomes positive which occurs 90° in phase after the signal 84 became positive, the transistor 80 becomes conductive and since both transistors 80 and 82 are now conductive current flows from the source +V through the primary winding 92 and limiting resistor 110 to circuit ground. The detector circuit 96 still does not apply a negative signal to enable AND gate 98 to pass the signal from oscillator 100 to the propulsion control 102. When the signal 84 returns to a zero voltage and the transistor 82 becomes not conducting to remove the current path from the source +V through the primary winding 92, this results in the magnetic field of transformer 94 collapsing and voltage is induced in the secondary winding 112. This induced voltage increase across the secondary winding causes the transistor 106 to conduct and current then flows from the source +V through the resistor 114 to circuit ground which causes the collector electrode of transistor 106 to go to essentially ground potential. The detector circuit 104 now provides a negative signal to AND gate 108 for enabling the latter gate to pass the signal from oscillator 100 to the propulsion control 102. The AND gate 98 is not enabled at this time so the propulsion control is not energized. When the signal 88 from tachometer 90 again returns to zero voltage, the transistor 80 becomes not conducting, the emitter electrode of transistor 80 returns to a zero volt level causing the detector circuit 96 to provide a negative signal to enable the AND gate 98 and permits the signal from oscillator 100 to reach the propulsion control 102. The propulsion control 102 is now operative such that the vehicle brakes 103 are not applied at this time and the vehicle motor 105 is permitted to continue movement of the vehicle along the track in a forward direction. The enable signals provided to the AND gates 98 and 108 remain at negative voltage levels, since the time constants of the detector circuits 96 and 104 respectively are chosen to maintain these enable signals as such for as long as the signals 84 and 88 from the tachometers 86 and 90 occur repetitively as shown in FIG. 5. Due to the coupling of transformer 94, if the phase relationship of the signals 84 and 88 from the respective tachometers 86 and 90 is reversed and the signal 84 becomes positive 90° in phase after the signal 88, the transistor 82 is turned on before the transistor 80 and the polarity of the signal at the secondary 112 of transformer 94 will not turn on the transistor 106. If one of the tachometers should fail and go static, transistor 106 will remain static and the negative enabling signal to AND gate 108 is no longer provided, or if the vehicle moves in a reverse direction, the control signal from oscillator 100 is no longer provided to the propulsion control 102 and this causes the application of the brakes 103 by the propulsion control 102. The underspeed detection apparatus 107 compares the decoded desired speed for the train vehicle with the actual speed as sensed by the tachometers 86 and 90. If the actual speed is less than the desired speed, the propulsion control is operated to cause the motor 105 to accelerate the train vehicle. If the actual speed is greater than the desired speed, the propulsion control 102 is operated to cause the brakes 103 to be applied. If the signal to the propulsion control 102 from the AND gates 98 and 108 is not provided, the brakes 103 will be applied. The operation of the underspeed detection apparatus 107 and the propulsion control 102 is well known to persons skilled in this art.
In reference to the signal integrity apparatus 28 shown in FIG. 4, the two vital direct current signals 30 and 32 are provided by the respective tachometers 22 and 24. If either of the two signals 30 and 32 should fail and not be provided for any reason, the full service brakes of the vehicle will be applied. The propulsion enable signal 34 is provided when the AND gates 60 and 62 are enabled by each of the respective signals 61 and 63 being negative. When the vehicle stops, the signal from signal source 70 is passed through to the output 38 when the AND gates 64 and 66 are enabled by the respective signals 61 and 63 each being positive. A positive bias voltage is included in each switching circuit 72 and 74 to make the respective signals 61 and 63 positive when the train vehicle stops. If the input signal 30 applied to switching circuit 72 is a negative voltage, the output signal 63 will be negative, and if the input signal 30 applied to switching circuit 72 is zero volts, the output signal 63 will be the positive supply voltage operative with the switching circuit 72.
In FIG. 7 there is schematically shown the switching circuits 72 and 74. Any failure in relation to the provision of the input signal 30 by the tachometer 22 cannot provide an output signal from the circuit 72 that is more negative than the vital direct current input signal 30, because the signal 30 is the source of any negative output signal 63 from the switching circuit 72. The ground reference 120 and the positive voltage supply are in relation to the most negative volt power supply in the circuit of FIG. 7, which is minus 15 volts. Thusly, the vital direct current output signal 63 becomes the most negative signal in the control system, and a failure of power supply 122 does not remove the desired fail-safe train vehicle control operation. In the operation of the switching circuit 72 shown in FIG. 7 the power supply 122 is the reference voltage, with a positive or a negative output signal 63 being in relation to the reference voltage of power supply 122. When the vehicle is moving in the proper direction the output signal 63 is negative. In the event of a failure of tachometer 22 or a tachometer detection circuit failure such that input 30 falls to a zero voltage level, the switching circuit 72 will switch that zero voltage level to a positive output signal 63. The operation of the switching circuit 74 is similar in relation to the input signal 32 from the tachometer 24.
With the train vehicle moving in the proper direction each of the vital direct current signals 61 and 63 shown in FIG. 4 will be negative and the transfer gates 60 and 62 now provide a path for the provision of the propulsion enable signal 34. If a failure condition occurs in relation to vital direct current signal 61, such that this signal now goes positive, the transfer gate 64 is enabled in addition to transfer gate 62 being enabled which results in not providing a zero speed enable signal 38 because the transfer gate 66 is blocking and in not providing the propulsion enable signal 34 because the transfer gate 60 is blocking. Thusly, the train vehicle will stop and the doors will not open.
With the known prior art apparatus a failure of just one vital DC signal was not detectable. The present apparatus does detect such a failure of one vital DC signal and that failure has to be corrected before the train vehicle can run along the track. This provides the desired vital zero speed detection.
A typical voltage doubler such as the detector circuits 96 and 104 shown in FIG. 6 is a capacitor pump circuit with a dynamic input having two charging capacitors. One switch when turned off allows one capacitor charge and when that same switch is turned on it references that one capacitor to zero volts and transfers its charge to the second capacitor. A negative voltage is thereby developed across the second and output capacitor.
The switching apparatus 72 and 74 as shown in FIG. 7 is referenced to minus 15 volts. The plus signal is established at about minus 10 volts. When the first tachometer 22 input is at minus 15 volts, the transistor 130 will turn off because it has minus 15 volts on the base and minus 15 volts on the emitter. The transistor 132 turns on since no current is flowing through the diode drops 134 and 136 and the resistor 138 goes to line voltage with the voltage at the anode of the diode 140 and the voltage drop across the base emitter junction of the transistor 132 being about 1.2 volts above the minus 15 volts so the transistor 132 will turn on. When the transistor 132 turns on, this turns on the transistor 142 which connects the minus 10 volts positive voltage to the output 63 going to the transfer gates 62 and 66. When the signal 30 is at minus 15 volts, which is the reference voltage, the transfer gate 62 is enabled. The transfer gate 66 is not enabled because it has reverse polarity applied to its control line. When signal 30 goes negative, this pulls the base of transistor 132 negative with respect to its emitter, which turns off the transistor 132 and this in turn turns off the transistor 142 to disconnect the plus power supply. Also the emitter of the transistor 130 is pulled negative with respect to minus 15 volts, with the resistor 144 being a base current limit, to turn on the transistor 142.
Thusly, before the propulsion enable signal 34 is provided both of the tachometers 22 and 24 have to be operating in a dynamic state with the vehicle moving, and before the zero speed or door open enable signal 38 is provided both of the tachometers 22 and 24 have to be in a static state with the vehicle stopped or at the equivalent of a zero speed. | A train vehicle zero speed sensing apparatus is provided for operation with a pair of tachometers coupled to the drive mechanism of a train vehicle, such that zero speed or an equivalent zero speed of the vehicle is sensed, and any single failure is detectable and will not yield a false zero speed indication. | 8 |
FIELD
[0001] This disclosure relates to the field of recovery of Unmanned Underwater Vehicles (UUVs).
BACKGROUND
[0002] UUVs may be irretrievably lost during underwater operation and be unable to return to the surface for a number of reasons. The UUV may inadvertently travel below a design depth, may be caught by debris or mud, may lose power and be unable to return to the surface, etc. By design, UUVs are often neutrally buoyant, which may require the UUV to utilize a propulsion system to return to the surface. However, propulsion may not be available when power is lost or the UUV incurs software and/or computer failures. The result is that the UUV may drift under water, making recovery nearly impossible.
SUMMARY
[0003] Embodiments described herein provide UUV recovery systems and methods that utilize multiple independent release mechanisms that can detach a load and allow the UUV to float to the surface of the water. The independent release mechanisms are each capable of releasing the load from the UUV utilizing different release criteria, thereby rendering the UUV positively buoyant when various conditions are met.
[0004] One embodiment is a recovery system for a UUV. The recovery system includes a detachable load that renders the UUV neutrally buoyant in water. The recovery system further includes a plurality of release mechanisms that are configured to detach the load to render the UUV positively buoyant in the water. The release mechanisms include a first, second, and third release mechanism. The first release mechanism is configured to detach the load in response to a command signal. The second release mechanism is configured to detach the load in response to the UUV being submerged in the water beyond a threshold time. The third release mechanism is configured to detach the load in response to the UUV exceeding a maximum depth in the water.
[0005] Another embodiment is a recovery system for a UUV. The recovery system includes a detachable load, a first release mechanism, a second release mechanism, and a third release mechanism. The load is configured to render the UUV positively buoyant in water upon release. The first release mechanism is configured to detach the load in response to a command signal. The second release mechanism is configured to detach the load in response to the UUV being submerged in the water beyond a threshold time. The third release mechanism is configured to detach the load in response to the UUV exceeding a maximum depth in the water.
[0006] Another embodiment is a method for operating a recovery system for an Unmanned Underwater Vehicle (UUV). The method comprises affixing a detachable load that renders the UUV neutrally buoyant in water. The method further comprises detaching the load in response to a command signal to render the UUV positively buoyant in the water. The method further comprises detaching the load in response to the UUV being submerged in the water beyond a threshold time to render the UUV positively buoyant in the water. The method further comprises detaching the load in response to the UUV exceeding a maximum depth in the water to render the UUV positively buoyant in the water.
[0007] The above summary provides a basic understanding of some aspects of the specification. This summary is not an extensive overview of the specification. It is intended to neither identify key or critical elements of the specification nor delineate any scope of the particular embodiments of the specification, or any scope of the claims. Its sole purpose is to present some concepts of the specification in a simplified form as a prelude to the more detailed description that is presented later.
DESCRIPTION OF THE DRAWINGS
[0008] Some embodiments are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings
[0009] FIG. 1 illustrates a vehicle that utilizes a recovery system in an exemplary embodiment.
[0010] FIG. 2 is a block diagram of a recovery system for the vehicle of FIG. 1 in an exemplary embodiment.
[0011] FIG. 3 is an isometric view of another recovery system for the vehicle of FIG. 1 in an exemplary embodiment.
[0012] FIG. 4 is an isometric view of a plurality of release mechanisms for the recovery system of FIG. 3 in an exemplary embodiment.
[0013] FIG. 5 is an isometric view of a cable and disk assembly for the recovery system of FIG. 3 in an exemplary embodiment.
[0014] FIGS. 6-8 illustrate a release scenario for detaching a load in an exemplary embodiment.
[0015] FIG. 9 is a flow chart of a method of operating the recovery systems of FIGS. 2-3 in an exemplary embodiment.
DESCRIPTION
[0016] The figures and the following description illustrate specific exemplary embodiments. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the embodiments and are included within the scope of the embodiments. Furthermore, any examples described herein are intended to aid in understanding the principles of the embodiments, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the inventive concept(s) is not limited to the specific embodiments or examples described below, but by the claims and their equivalents.
[0017] FIG. 1 illustrates a submersible vehicle 100 that utilizes a recovery system in an exemplary embodiment. In this embodiment, vehicle 100 is depicted as an Unmanned Underwater Vehicle (UUV), although in other embodiments, vehicle 100 may be any type of vehicle that is able to submerge under water and utilize a recovery system to ensure that vehicle 100 may be recovered at the surface when various recovery criteria are met. For instance, vehicle 100 may inadvertently dive past a pre-determined depth, which triggers the recovery system to return vehicle 100 to the surface. Vehicle 100 may exceed a pre-determined amount of time under water, which triggers the recovery system to return vehicle 100 to the surface. Vehicle 100 , or some other entity, may generate a command signal which triggers the recovery system to return vehicle 100 to the surface.
[0018] FIG. 2 is a block diagram of a recovery system 200 for vehicle 100 of FIG. 1 in an exemplary embodiment. In this embodiment, recovery system 200 includes a plurality of release mechanisms 202 - 204 that are mechanically coupled to a detachable load 206 . Load 206 may include a portion of vehicle 100 and/or a drop weight that is able to be detached from vehicle 100 in some embodiments. In this embodiment, load 206 renders vehicle 100 substantially neutrally buoyant in water, and renders vehicle 100 positively buoyant in water when load 206 is released from vehicle 100 . When load 206 is released, vehicle 100 is able to float to the surface of the water and be recovered.
[0019] Release mechanisms 202 - 204 operate substantially independently to ensure that load 206 is detached from vehicle 100 when certain conditions are met. This ensures vehicle 100 may be recovered. Release mechanism 202 in this embodiment comprises any component, system, or device that is able to detach load 206 in response to a command signal. The command signal may be generated by vehicle 100 and/or by another entity, such as a support vessel. For instance, vehicle 100 may generate a command signal to detach load 206 if vehicle 100 becomes stuck and is unable to surface (e.g., stuck in mud, ensnared in fishing gear, etc.).
[0020] Release mechanism 203 in this embodiment comprises any component, system, or device that is able to detach load 206 in response to vehicle 100 being submerged in the water beyond a pre-determined time. For instance, if vehicle 100 loses power and drifts under water beyond a pre-determined amount time, then release mechanism 203 acts to detach load 206 and cause vehicle 100 to float to the surface of the water.
[0021] Release mechanism 204 in this embodiment comprises any component, system, or device that is able to detach load 206 in response to vehicle 100 exceeding a maximum depth in the water. For instance, if vehicle 100 loses power or becomes negatively buoyant, then vehicle 100 may sink below a pre-determined depth in the water. In this case, release mechanism 204 acts to detach load 206 and cause vehicle 100 to float to the surface of the water.
[0022] Because release mechanisms 202 - 204 act substantially independently of each other to detach load 206 and render vehicle 100 positively buoyant, vehicle 100 is more likely to be recovered on the surface of the water in response to a variety of possible failures that may otherwise cause vehicle 100 to be lost.
[0023] FIG. 3 is an isometric view of another recovery system 300 for vehicle 100 in an exemplary embodiment. In this embodiment, recovery system 300 includes a plurality of release mechanisms (not visible in this view) which are surrounded by a housing 306 . Housing 306 of recovery system 300 is fixed to a shell 304 , which surrounds a detachable load 302 . In this embodiment, load 302 is a drop weight, although in other embodiments load 302 may include portion(s) of vehicle 100 . For instance, load 302 may be an instrument package for vehicle 100 , may be external lights for vehicle 100 , etc. Thus, it is not intended that load 302 in this embodiment be limited to only drop weights.
[0024] In this embodiment, load 302 is able to slide within shell 304 and detach from recovery system 300 when certain conditions are met. While load 302 remains connected to recovery system 300 (which is part of or is mounted to vehicle 100 ), vehicle 100 is approximately neutrally buoyant. This allows vehicle 100 to operate under water without incurring a buoyancy penalty (e.g., either positively or negatively) when utilizing recovery system 300 . However, when load 302 is dropped, released, detached, etcetera, from recovery system 300 (and consequentially also from vehicle 100 ), vehicle 100 becomes positively buoyant. With positive buoyancy, vehicle 100 floats to the surface of the water, which allows for the recovery of vehicle 100 .
[0025] FIG. 4 is an isometric view of release mechanisms 402 - 404 for recovery system 300 of FIG. 3 in an exemplary embodiment. In this view, housing 306 (see FIG. 3 ) has been removed to allow for the visibility of release mechanisms 402 - 404 . In this embodiment each of release mechanisms 402 - 404 are capable of operating independently to detach load 302 from recovery system 300 . Release mechanisms 402 - 404 are detachably coupled to a disk 405 , which is mounted to load 302 . However, in other embodiments, release mechanisms 402 - 404 may be detachably coupled to load 302 in any number of ways as a matter of design choice. Further, although disk 405 is depicted as substantially round, disk 405 may include other shapes as well. For instance, disk 405 may oblong, rectangular, triangular, etc. Disk 405 may be referred to as a weigh distribution plate in some embodiments.
[0026] Release mechanism 402 in this embodiment is an active release, and is able to detach load 302 from recovery system 300 in response to receiving a command signal. For instance, vehicle 100 may generate a command signal to detach load 302 from recovery system 300 . Release mechanism 402 includes a pair of redundant actuator coils 414 which are used to release load 302 , although in other embodiments only one coil 414 may be used. Vehicle 100 , or some other entity such as a ship or an operator, may generate the command signal to release load 302 in cases where vehicle 100 is unable to return to the surface. For example, if a propulsion system for vehicle 100 fails, then vehicle 100 may generate the command signal actuating coils 414 . Coils 414 are mechanically coupled to a fixed arm 406 (which may be bonded to housing 306 ) and hold a movable arm 408 in place until coils 414 are actuated. Movable arm 408 is rotatably coupled to fixed arm 406 by a pin 407 . Upon actuation, movable arm 408 rotates out of position along a pin 407 coupled to fixed arm 408 , which causes movable arm 408 to decouple from disk 405 and release load 302 from shell 304 . This imparts positive buoyancy to vehicle 100 and allows vehicle 100 to float to the surface of the water for recovery.
[0027] Release mechanism 403 in this embodiment is a passive release, and is able to detach load 302 from recovery system 300 in response to how long recovery system (and consequentially vehicle 100 ) is in and/or under the water. Release mechanism 403 may include a breakable link 410 , which corrodes in salt water at a known rate. When link 410 breaks, movable arm 408 rotates with respect to fixed arm 406 (which may be bonded to housing 306 ) along pin 407 , which causes movable arm 408 to decouple from disk 405 and allows load 302 to be released from shell 304 . For example, if vehicle 100 loses power or becomes entangled or trapped under water, link 410 eventually corrodes until link 410 breaks, which detaches load 302 from recovery system 300 . This imparts positive buoyancy to vehicle 100 , which is able to float to the surface and be recovered.
[0028] Release mechanism 404 in this embodiment is another passive release, and is able to detach load 302 from recovery system 300 in response to recovery system 300 (and consequentially vehicle 100 ), exceeding a maximum depth. Release mechanism 404 may include a burst plug 412 or some other device which actuates in response to a pressure setting. For instance, if vehicle 100 sinks below a pre-determined depth in the water, burst plug 412 ruptures and causes load 302 to be released from recovery system 300 . This imparts positive buoyancy to vehicle 100 and allows vehicle 100 to float to the surface of the water and be recovered. The particulars of how release mechanism 404 may operate will be discussed with respect to FIG. 5 .
[0029] FIG. 5 is an isometric view of a cable 502 and disk 405 assembly for the recovery system of FIG. 3 in an exemplary embodiment. In this view, the relationship between disk 405 and movable arms 408 is more clearly shown. Movable arms 408 include a hooked portion which allows disk 405 to be held or captured in place until any of movable arms 408 rotate out of position. Load 402 in this view is coupled to disk 405 utilizing a linkage and/or cable 502 . This allows load 402 to hang by cable 502 and remain part of recovery system 300 until disk 405 is dropped or titled out of position between movable arms 408 . Although FIG. 5 illustrates that each of movable arms 408 are located approximately equidistant around disk 405 , other configurations may exist. Referring again to release mechanism 404 , burst plug 412 couples movable arm 408 to fixed arm 406 (which may be bonded to housing 306 ) until burst plug 412 ruptures. In response to burst plug 412 rupturing, movable arm 408 rotates out of position with respect to fixed arm 406 along pin 407 , which causes movable arm 408 to decouple from disk 405 and allows load 302 to be released from shell 304 .
[0030] FIGS. 6-8 illustrate a release scenario for detaching load 302 in an exemplary embodiment. Although FIGS. 6-8 illustrate the actuation of release mechanism 403 , which is based on the amount of time vehicle 100 is in and/or under the water, any of the other release mechanisms 404 - 405 may operate in a similar manner to allow disk 405 to rotate out of position and release load 302 from recovery system 300 .
[0031] In FIG. 6 , link 410 is illustrated as releasing movable arm 408 , which pivots movable arm 408 toward the left in FIG. 6 along pin 407 . As movable arm 408 rotates, the capture of disk 405 is lost. Disk 405 begins to tilt, as illustrated in FIG. 7 . As disk 405 tilts and capture is lost (see FIG. 8 ), disk 405 becomes unstable and is able to slide out of position between movable arms 408 for each of release mechanisms 402 - 404 . As disk 405 is mechanically coupled to load 302 via cable 502 , load 302 is able to drop away from recovery system 300 , which then imparts positive buoyancy to vehicle 100 . Vehicle 100 is then able to float to the surface of the water for recovery.
[0032] One advantage of recovery system 300 is that it includes a plurality of independent release mechanisms 402 - 404 , each of which are capable of releasing load 302 and allowing vehicle 100 to float to the surface. FIG. 9 is a flow chart of a method 900 of operating the recovery system of FIGS. 2-8 in an exemplary embodiment. The steps of method 900 will be described with respect to recovery system 200 ; although one skilled in the art will understand that method 900 may be performed by other devices or systems not shown. The steps of method 900 are not all inclusive and may include other steps not shown. Further, the steps may be performed in an alternate order.
[0033] In step 902 , a detachable load (e.g., load 206 ) is affixed to a UUV (e.g., vehicle 100 ). The load may be part of the UUV and/or a drop weight, or some combination thereof. In step 904 , if a command signal has been received, then the load is detached from the UUV in step 910 and the UUV floats to the surface. If a command signal has not been received, then step 906 is performed. In step 906 , if the UUV has been submerged under water beyond a time limit, then the load is detached in step 910 and the UUV floats to the surface. If the UUV has not been submerged beyond the time limit, then step 908 is performed. In step 908 , if the UUV has sunk below a pre-determined depth under the water, then the load is detached in step 910 and the UUV floats to the surface. Each of steps 904 - 908 may be performed nearly simultaneously. If none of the previous conditions for detaching the load occurs, then the load may not be detached from the UUV.
[0034] Although specific embodiments were described herein, the scope is not limited to those specific embodiments. Rather, the scope is defined by the following claims and any equivalents thereof. | Embodiments described herein provide a highly reliable UUV recovery systems and methods that utilize multiple independent release mechanisms that can detach a load and allow the UUV to float to the surface of the water. One embodiment is a recovery system for a UUV. The recovery system includes a detachable load that renders the UUV neutrally buoyant in water. The recovery system further includes a plurality of release mechanisms that detach the load to render the UUV positively buoyant in the water. The release mechanisms include a first, second, and third release mechanism. The first release mechanism detaches the load in response to a command signal. The second release mechanism detaches the load in response to the UUV being submerged in the water beyond a threshold time. The third release mechanism detaches the load in response to the UUV exceeding a maximum depth in the water. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates to a fixation insert having improved "back riveting" ("flash-through") safety, consisting of a planar textile structure of natural and/or synthetic threads or fibers and a coating of a thermally softenable adhesive compound applied on the front of the structure.
Fixation inserts are materials with stiffening action which can be cemented to the inside or back of outer materials by a coating of adhesive compound and which impart to the outer materials the desired fashionable drape, fit and feel.
It is desirable to make fixation inserts of as light a weight as possible so as to increase the "breathing" ability of the overall material, ensure wearing comfort and minimize material costs.
Fixation inserts are provided on their surface with a layer of thermoplastically softenable adhesive compound, usually in a geometric pattern. The inserts are placed with this layer on the back of the outer material and subsequently ironed over. In the ironing process, the adhesive compound is thermally softened. It enters into an adhesive bond with the inside of the outer material, and more or less firm adhesion results after cooling.
An intended effect on the property of the outer material is possible only if the adhesion achieved between the fixation insert and the outer material is of high quality, i.e., if the amount of thermoplastic adhesive compound per unit area does not fall below a certain minimum. In the case of light weight fixation inserts, for example, those of planar textile structures with an area weight of less than 60 g/m 2 , considerable difficulties can arise since the required amount of adhesive compound can easily penetrate through the planar structure to the back thereof and not only dirty the ironing apparatus but can also make it stick to the planar structure. In this case, the term "back-riveting" or "flash-through" is used to describe this extremely undesirable effect.
To overcome these difficulties, it has been proposed to use only heavy weight non-woven fabrics with an area weight of, for example, more than 70 g/m 2 for the production of fixation inserts. A decrease in the breathing ability of the materials, however, must be tolerated in such a case.
DE-AS No. 24 61 845 relates to a fixation insert of a woven or knit fabric or a non-woven fabric, on the top side of which a bonding agent is applied in a fine, raster-shaped print under a correspondingly large amount of adhesive compound. The bonding agent is chemically cross-linked, whereby it is unable to soften during the ironing operation. It can, therefore, block the pore structure of the planar structure during the softening of the adhesive compound and in this manner prevent the adhesive compound from penetrating through the planar structure. The application of defined amounts of the bonding agent and the adhesive compound in closely adjacent zones with a diameter of 0.5 to 1 mm in working widths of more than 1 m, however, is so trouble-prone that the manufacture of such fixation inserts on a large commercial scale is problematical.
From Krema, Handbuch der Textilstoffe, Deutscher Fachverlag GmbH, Frankfurt, 1970, page 191-192, it is known to cover a base material provided with an adhesive layer from above or below with short fibers in an electrostatic field.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fixation insert having improved back-riveting or flash-through safety which is easy to produce and which permits the use of planar structures with reduced area weight.
This and other objects are achieved by the provision of a fixation insert of the type mentioned at the outset wherein the planar structure has, at least on the back side thereof, a fiber layer of elastically resilient fibers which extend from the surface substantially perpendicularly.
As a rule, planar textile structures have fiber ends or loops which extend freely from the surface. However, these are not oriented predominantly perpendicularly and they are bound and sized so that there is no measurable elastic resiliency.
The fixation insert of the present invention, on the other hand, has fibers which extend over the surface substantially perpendicularly and have measurable elastic resiliency. As a consequence, the fibers can be laid-over on one side, without reduction of their elasticity, under the action of a lateral force (for example, the pressure of an ironing plate) and to push the still warm planar structure away therefrom, avoiding back-riveting, when the pressure is released. With respect to the overall weight of the required amount of fibers, surprisingly considerable savings are obtained. Area weights of 18 to 20 g/m 2 with 12 to 14 g/m 2 fiber weight of the base material can be realized without difficulty. The mechanical properties of the available fiber materials can be brought to bear in an optimum manner, as referred to the starting weight, and improved drapability and improved feel are obtained as further advantages.
The planar structure may consist of a woven or knit fabric and/or non-woven fabric. It can, therefore, be adapted optimally to different applications. According to one advantageous embodiment, it is provided that the planar structure be built up with several individual layers, with the individual layers being connected to each other in such a manner that the threads of the individual layers are offset relative to each other. Each individual layer need have only very little thickness and may consist, for example, of a very light gauze. Overall, good surface coverage is achieved nevertheless. The fiber layer applied at least to the back side consists preferably of short fibers which are flaked-on in an electrostatic field and joined to the threads of the planar structure by an elastic bonding agent. The short fibers are oriented predominantly perpendicularly to the surface of the planar structure and they are connected at one end elastically to the threads of the planar structure. Also if short fibers of basically inelastic materials are used, for example, of polyamide 6, polyamide 66, polyester, polyacryl, staple fiber or cotton, great elasticity is therefore ensured in all cases.
The flexibility and the textile feel of planar textile structures can be reduced by too high a bonding agent content. In those cases where a bonding agent is required for reinforcing the planar structure, as, for example, in non-woven fabrics, it has been found to be advantageous to utilize the bonding agent required for binding the short fibers at the same time for cementing the fibers of the planar structure together. Furthermore, extremely economical bonding agent consumption results.
The distribution of the bonding agent in the planar structure can be controlled in a targeted manner by adjustment. For example, the bonding agent can be concentrated in laminate-fashion at the crossings of the threads of the planar structure, and the short fibers are then also arranged in these zones. According to another embodiment, a bonding agent is used which envelops the threads of the planar structure in film-fashion without forming special thick spots at the fiber crossings. The short fibers of equal length which are used in the electrostatic deposition are deposited in this case not preferably on the threads of the planar structure which directly touch the front, but penetrate with the same distribution into the spaces between such threads and can therefore be cemented with the threads arranged on the inside. The effect manifests itself particularly distinctly in planar structures which are built up with several layers, the individual threads of which are offset relative to each other. The nap formed by the short fibers exhibits in one such embodiment a uniformly distributed surface showing irregularities with a character that appears particularly textile-like. Feel and drapability are improved greatly in such cases.
The titer of the short fibers used should be 0.5 to 7 dtex for a fiber length of 0.3 to 3 mm, and preferably 1.3 to 3.3 dtex for a fiber length of 0.5 to 1 mm.
It is not absolutely necessary to deposit short fibers on the planar structure in a continuous layer. Indeed, it has been found that extremely high back-riveting safety is obtained even if the fiber layer has interruptions which are distributed over the area in a pattern. The fiber layer may be limited, for example, to circular areas each having a diameter of 1 to 2 mm with the same mutual spacing. Other geometric patterns, signatures, etc. are conceivable without difficulty. For the practical realization it is merely necessary to apply the bonding agent in an appropriate manner to the planar structure, for example, by spraying, impregnating or printing, to apply the short fibers in the electrostatic field, to solidify the bonding agent and to remove the fibers which have not bound in to the structure by suitable means, for example, by suction.
The ratio of the weight of the short fibers per unit area and the weight of the planar structure should be 0.5 to 2.5, referred to the absolute mass of the fibers. The required amount of bonding agent is not affected thereby.
Fixation inserts usually are manufactured by first producing a planar structure of textile fibers and subsequently coating the structure on the front with a thermally softenable adhesive compound. According to the state of the art, the adhesive compound can be applied as a continuous as well as a discontinuous layer; in all cases, however, there if a danger, with decreasing quantity of fibers, of back-riveting when hot-pressing.
According to the present invention, this problem is solved, in a method of the type described above, by the provision that the planar structure is printed or impregnated with an elastic bonding agent; that a layer of short fibers is loosely deposited at least onto the backside of the structure in an electrostatic field; that the bonding agent is cross-linked; and that the front of the planar structure is coated with an adhesive compound. The proposed process can be carried out simply on a large commercial scale. Short fibers which are not bound-in can be suctioned off without loss from the surface of the finished planar structure and used over again. The amount of fibers required to ensure high back-riveting safety is reduced considerably as compared to known methods.
According to a particular embodiment of the present invention, it is provided that the planar structure is solidified prior to the printing or impregnating. In the case of non-woven planar structures, for example, spun-bonded fabrics, such solidification is generally used and can be brought about, for example, in the case where thermoplastic fibers are present, by activating the fibers. In all other cases, solidification can be achieved by embedment and subsequent cross-linking of a bonding agent, if desired, in areas spaced from each other. The bending elasticity and stiffening force can be influenced by such solidification in a controlled, predetermined manner, which is of great importance for the later modification of a stiffening insert.
The required adhesive compound can be brushed as a continuous layer on the front side of the planar structure and generated, for example, by sintering a polyethylene powder together. With respect to ensuring improved air permeability, it has been found to be advantageous to print the adhesive compound in a geometric pattern, where the usual geometric distributions can be employed. The area weight of the adhesive compound should be 10 to 25 g/m 2 in fixation inserts for use as insert materials in the apparel field, and in fixation inserts for use in automobile ceilings, 15 to 40 g/m 2 .
Yet additional improvement of the back-riveting or flash-through safety is obtained using a method in which the planar structure is printed from the back with an elastic bonding agent and at the same time, printed from the front, immediately opposite, with a thermally softenable adhesive compound, provided that a fiber layer of short fibers is loosely deposited into the back side of the structure in an electrostatic field. The structure so obtained is subsequently finished at a temperature such that the bonding agent is cross-linked and the adhesive compound dried. The method is suitable primarily for the treatment of planar structures of non-woven fiber material, preferably an unsolidified non-woven fabric, and, in single-stage operation, leads directly to a fixation insert which has an adhesive compound on the front and a fiber nap on the rear side. In such a method, the bonding agent preferably is printed in partial areas which completely cover the partial areas in which the adhesive compound is printed. The partial layers of adhesive compound, which increase in diameter as they are softened and pressed together with the outer material, thereby can not leave the areas of the partial layers covered by the bonding agent. Within this region, the pore structure of the planar structure is largely blocked by the bonding agent, for which reason the adhesive compound cannot flash through, when softening, to the back side of the planar structure.
Any elastically resilient polymer materials may be used as bonding agents. Prefereably, however, photo-polymerizable bonding agents are employed. The requirement per unit area is particularly small in this case and it is possible to achieve high operating speeds. The cross-linking is accomplished by ultra-violet radiation.
There are no special limitations with respect to the applicable planar textile structures. To the extent that non-woven fabrics are concerned, these can be produced by a dry or a wet process. The use of spun-bonded fabric also is possible.
The fixation insert of the present invention is distinguished from the known inserts by particularly high back-riveting (flash-through) safety which manifests itself particularly in the case of thin, light weight materials having an area weight of less than 60 g/m 2 . Planar structures of relatively low-quality fibers are distinctly upgraded with respect to dry-cleanability and with respect to washability and abrasion resistance.
The feel of the fixation insert is fuller and bulkier and these properties are preserved even after hot pressing. The air permeability and the breathing activity of the insert are not impaired at all.
The above-described fixable insert materials for apparel are also particularly well suited for use as fixable textile interior linings that can be ironed-on in self-supporting car ceiling systems in the automotive industry. It is known that the carrier materials in such cases consist of fully impregnated cardboard, Styropor, phenolic resin, grained cotton fiber fabrics or non-woven glass fiber fabric which are deformable in a pressing operation under the action of heat. It is the purpose of these car ceilings not only to reduce the labor effort and to have a heat-insulating effect but also to bring about substantial improvement in the acoustical characteristics of the interior of the vehicle by providing a sound-insulating or sound-absorbing effect. To this end, the self-supporting car ceilings which are produced so as to be as light weight as possible, must have a defined air permeability, i.e., a favorable flow resistance. For this reason, air-permeable foam systems or perforated material have recently been used for such purposes.
The corresponding textile inside lining which can be cemented to the car ceiling also has the purpose to be deformed during the heat pressing and to be cemented to the carrier in the process. The acoustic effect of the car ceiling system is not adversely affected by the adhesive compound which is applied in dot or raster fashion, as compared to application of the adhesive over the entire area, but can even be improved, depending on the choice of the raster or dot size and dot density, and can thereby exert a positive influence on the flow resistance. Deposition of short fibers according to the present invention makes possible the use of planar textile structures having a low weight per square meter while preserving good abrasion resistance and good appearance, and preventing "back-riveting" of the adhesive compound from taking place at the molds during the deformation and cementing, which otherwise might lead to disturbances in the manufacture and to contamination of the surfaces.
BRIEF DESCRIPTION OF THE DRAWING
A non-woven fabric according to the present invention is shown schematically in the attached drawing in a longitudinal section.
DETAILED DESCRIPTION OF THE INVENTION
The non-woven fabric shown in the drawing is constructed of one layer and consists of threads 1 which are united to form an open thread structure. The threads are impregnated continuously with a bonding agent film, not shown, into which the ends of the short fibers 2 are bound, which are deposited perpendicularly. The short fibers 2 have the same length relative to each other but, because the position of their attachment at the individual threads differs, they extend beyond the surface of the non-woven fabric at different heights, whereby the fabric is given a regular/irregular textile-like appearance. Because of their own elasticity and the elasticity of the bonding agent, the short fibers can be bent elastically to one side and straighten out again automatically when the load is released. They therefore act as spacers and prevent direct mechanical contact between the flatiron and the surface of the threads 1 coated with the bonding agent if they are wetted with the adhesive compound 3 which is thermoplastically softened in hot-pressing. Sticking between the non-woven fabric and the ironing device, the so-called back riveting (flash-through), is prevented in this manner.
The term "open thread structure" or "open fiber structure" in the sense of the present invention is understood to mean a thread distribution in which the threads reach distances between their contact points which are at least 5 to 20-times as large as the diameter of the flake-deposited short fibers.
The subject of the present invention is explained in greater detail with reference to the following examples.
EXAMPLE 1
A length-wise oriented carded non-woven fabric of 14 g/m 2 of 100% polyethylene terephthalate fibers with a titer of 1.3 dtex and a cut length of 38 mm is impregnated with a bonding-agent polymer dispersion of butylacrylate, methylolacrylamide and acrylonitrile in the ratio 90:4:6, so that 10 g/m 2 dry bonding agent are present in the finished product. Onto the impregnated, still wet non-woven fabric, 10 g/m 2 short-cut fibers of nylon 6.6 with a titer of 1.7 dtex and a cut length of 0.75 mm are applied in an electrostatic field. Subsequently the flaked fibers are bound-in simultaneously in a suitable drier and the bonding of the fiber fabric, the drying and cross-linking of the bonding agent take place.
In a second operation an adhesive compound of copolyamide at a 17-mesh distance and a coating of 14 g/m 2 is applied and dried.
When this non-woven fabric, which contains 24 g/m 2 fibers, among them 10 g/m 2 flaked-on short fibers, is ironed to an outer material on an ironing press for 10 seconds at 150° C., 350 mbar, it remains lying flat on the lower plate after the press is opened, which indicates freedom from back-riveting. In a non-woven fabric with 24 g/m 2 polyester fibers, bound completely, but without flaked-on short fibers, the adhesive compound flashes through under the same conditions, and the laminate is stuck to the top side of the ironing board.
In the determination of the drapability according to DIN 54 306, the non-woven fabric exhibited distinctly better drapability as compared to an insert having the same fiber content and weight per square meter (but without short fibers bound therein), as confirmed by the following values:
Flaked goods from Example 1: 55.33%
Not-flaked goods: 65.73%
In the test for air permeability according to DIN 53 887, it was found that a light weight non-woven fabric with high air permeability barely looses its permeability property if an additional 10 g/m 2 short fibers are applied perpendicularly to the surface. If, however, the same amount of 10 g/m 2 fibers is incorporated into the base fabric, the air permeability decreases (in proportion to the increasing fiber content per m 2 ). This is confirmed by control measurements, the results of which are given below, on non-woven fabrics with comparable fiber content.
Air permeability under a pressure of 0.5 mbar:
non-flaked goods, 24 g/m 2 fiber: 1250 l/sec m 2
flaked goods, 24 g/m 2 fiber: 1600 l/sec m 2
non flaked goods, 14 g/m 2 fiber: 1800 l/sec m 2
EXAMPLE 2
A carded and cross-laid non-woven fabric of 22 g/m 2 of a mixture of 80% polyethylene terephthalate fibers with a titer of 1.7 dtex and 20% copolyester fibers of polyethylene terephthalate and polybutylene terephthalate with a melting point of 190° C. are welded together under pressure and heat in raster-fashion.
Subsequently, 8 g/m 2 of a condensed bonding agent dispersion of butylacrylate-methylolacrylamide and acrylonitrile polymerizate are applied in a ratio of 90:4:6 at a 25-mesh distance and the fabric is conducted into an electrostatic field, in which 10 g/m 2 short-cut fibers of polyethylene terephthalate with a titer of 1.7 dtex and a cut length of 0.75 mm are applied. The flaked short-cut fibers are bound-in and the bonding agent is dried and cross-linked in a drier. Subsequent cleaning via brush cylinders with suction removes the excess short fibers which are not bound in to the fabric.
In a further operation, an adhesive compound of copolyamide is applied dry at a 17-mesh distance with a coating thickness of 14 g/m 2 on the backside and is dried. When this non-woven fabric, which contains 32 g/m 2 fibers, among which are 10 g/m 2 flaked-on short fibers, is hot-pressed onto an outer material for 10 seconds at 150° C., 350 mbar on a fixation ironing press, it remains flat on the lower plate after the press is opened, which indicates freedom from back-riveting of the adhesive compound. In a non-woven fabric with 32 g/m 2 polyester fibers bound completely, without flaked-on short fibers, the adhesive compound flashes through under the same conditions, and the laminate sticks to the upper side of the plate.
The two non-woven fabrics differ as to drapability according to DIN 54 306 in the same manner as in accordance with Example 1. For the air permeability according to DIN 53 887, the observations of Example 1 also apply.
EXAMPLE 3
A carded lengthwise-oriented non-woven fabric of 14 g/m 2 of 100% polyethylene terephthalate fibers with a titer of 1.3 dtex and a fiber length of 38 mm is applied, as described in DE-OS No. 29 14 617, in one operation from the one side with 10 g/m 2 bonding agent (dry) of butyacrylate-methylolacrylamide and acrylonitrile in the ratio of 90:4:6 and from the other side, 14 g/m 2 (dry) of an adhesive compound of copolyamide is applied, always exactly opposite the bonding agent, at a 25-mesh distance. The undried fabric is brought into an electrostatic field in which 10 g/m 2 short fibers of nylon 6.6 (titer of 1.7 dtex and a cut length of 0.75 mm) are applied on the side where the bonding agent was applied. In the subsequent drier, the bonding agent is cross-linked and the adhesive compound is dried. Cleaning via brushing cylinders with suction removes the excess, short fibers which are not bound in to the fabric.
When this non-woven fabric, which contains 24 g/m 2 fibers, among them 10 g/m 2 short fibers, is hot-pressed on an outer material for 10 seconds, at 150° C. and 350 mbar on a fixing plate press, it remains lying flat after the press is opened, which indicates freedom from back-riveting of the adhesive compound. In the case of a non-woven fabric with 24 g/m 2 polyester fibers, completely bound and without applied short fibers, the adhesive compound flashes through under the same conditions and the laminate sticks to the upper side of the plate.
The two non-woven fabrics differ as to drapability according to DIN 54 306 in the same manner as according to Example 1.
For the air permeability according to DIN 53 887, the same observations apply for this Example as in the preceding Example 1. | Disclosed herein is a fixation insert having improved resistance to back-riveting (flash-through) and a method for the manufacture thereof, consisting of a planar textile structure of natural and/or synthetic threads and a coating, applied to the front side, of a thermally softenable adhesive compound, where the planar structure has at least on the back side a layer of fibers which extend beyond the surface of the planar structure predominantly perpendicularly, and where the fibers are elastically resilient. The fibers are elastically connected to the threads and are deposited thereon in an electrostatic field. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present Application is based on International Application No. PCT/EP2005/0528929, filed on Jun. 17, 2005, which in turn corresponds to French Application No. 04/06782 filed on Jun. 22, 2004, and priority is hereby claimed under 35 USC § 119 based on these applications. Each of these applications are hereby incorporated by reference in their entirety into the present application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the invention is that of electronic devices for generating synchronization signals. More specifically, the technical field is that of very high resolution synchronization signals, the temporal accuracy of the signals being less than a nanosecond. These devices are in particular used in the laser subsystems that deliver high-energy, ultra-brief laser pulse trains, the duration of the pulses being of the order of a few hundreds of femtoseconds and their energy being of the order of a terawatt.
2. Description of the Invention
These subsystems more often than not comprise a large number of optoelectronic elements needed for generating, amplifying and formatting the laser pulses and elements for controlling, monitoring and measuring these pulses. Now, the pulses emitted are of very brief duration, so it is vitally important to synchronize the various elements of the subsystem with a high temporal accuracy so as to ensure both optimal operation of the subsystem and the best possible reproducibility of the emitted pulses.
The current synchronization devices present a certain number of drawbacks. On the one hand, the internal clock of these various devices is not necessarily perfectly synchronized with an external signal taken from an element of the system to be synchronized. On the other hand, when the system comprises a large number of elements to be synchronized it becomes impossible to synchronize them all with a single synchronization device. In this case, several synchronization devices are used, these devices being synchronized between themselves by trigger devices. These triggers are produced from clock signals internal to the synchronization devices. These clock signals are periodic. It can be demonstrated that the triggering accuracy is equal to a period of the clock signal. For example, for a clock signal emitted at a frequency of 100 megahertz, the synchronization accuracy is then equal to one period, or 10 nanoseconds. This accuracy is not sufficient, for certain applications, to permit a perfect synchronization of the various elements of the system.
To overcome these drawbacks, the device can operate no longer with an internal clock but with an external clock taken from the device to be synchronized. Thus, any temporal drift and any triggering inaccuracy of the synchronization signals is avoided. However, this solution presents the drawback that, if the external signal disappears, the entire synchronization devices can no longer function. The disappearance of the synchronization signals can then have serious consequences. In practice, the breakdown of the external clock signal is the manifestation of a malfunction of the system to be synchronized. For some applications, in particular in pulsed laser subsystems, it is important to take measures to protect the elements of the subsystem that can be damaged by this malfunction. Such is the case in particular with power amplifiers which must operate only in the presence of the laser beam to be amplified.
The device according to the invention comprises a security device for compensating for the malfunctions of the external clock by the provision of an internal clock which takes over from the external clock in the event of a malfunction. The device also comprises electronic management means for continuing to manage the system to be synchronized and so prevent elements from being damaged.
SUMMARY OF THE INVENTION
More specifically, the subject of the invention is an electronic device for generating synchronization signals from a first external clock signal emitted at a first oscillation frequency, said signal being supplied to an input called a clock input, characterized in that said device comprises at least:
an internal clock emitting an internal clock signal oscillating at a second frequency roughly identical to the first frequency; first electronic security management means, arranged so that said internal clock signal replaces the external clock signal if the latter malfunctions.
Advantageously, the first electronic security management means allow for the preprogrammed application or stopping of certain synchronization signals in the event of loss of the external clock signal. Furthermore, the device comprises second electronic means of controlling external electronic devices, of electrical power supply device type or of electromechanical device type or of security system type, said signals being delivered to electronic control outputs, said second means being controlled by the first electronic security management means.
Advantageously, the first security management means include means of switching off all the devices controlled by the synchronization device at the end of a predetermined period following the loss of the external clock signal. The first electronic means mainly comprise a programmable digital component, for example of the FPGA (Fast Programmable Gate Array) type.
The device includes electronic interface means with a microcomputer, said microcomputer making it possible to control and program the functions of the device.
The device according to the invention conventionally comprises:
electronic means of formatting the external clock signal so as to obtain a sinusoidal signal of frequency identical to the first oscillation frequency; electronic means of generating from said sinusoidal signal:
a first periodic synchronization signal S 0 being used as a timebase reference, said signal having a first repetition frequency, said signal being supplied to an electronic output called a reference output. a plurality of second periodic synchronization signals S SYNC , said second signals being offset by a programmable time relative to the first synchronization signal and having second repetition frequencies which are also programmable, said second signals being supplied to electronic outputs called programmed delay signal outputs. means of generating a second external synchronization clock signal having a frequency identical to the first external clock signal, said signal being supplied to an electronic output called a clock output.
The device according to the invention applies more particularly to a laser subsystem comprising at least the following optoelectronic elements:
a local oscillator emitting an optical beam in the form of laser pulse trains; an energy amplification subsystem; means of spatially and temporally formatting the optical beam; means of controlling, monitoring and measuring; a semi-reflecting optical splitter placed at the output of the local oscillator; a photodiode placed on one of the channels of said splitter so as to receive a part of the optical beam, said photodiode delivering an electrical signal representative of said optical beam; an electronic device or system for generating synchronization signals according to the invention, the electrical signal taken from the photodiode being used as a clock signal for said device or said system, the synchronization signals S SYNC taken from said device or from said system being used to synchronize the various optoelectronic elements of the subsystem.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and other advantages will become apparent from reading the description that follows, given by way of nonlimiting example and with reference to the appended figures in which:
FIG. 1 represents the general block diagram of the device according to the invention;
FIG. 2 represents the diagram of the operating protocol of the security device according to the invention;
FIG. 3 represents a laser subsystem incorporating a device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
As a nonlimiting example, FIG. 1 represents an electronic device for generating synchronization signals 1 according to the invention. It mainly comprises:
electronic means of filtering 110 , amplifying 111 and level-setting 112 , for formatting an eternal clock signal so as to obtain a positive sinusoidal signal of frequency identical to the first oscillation frequency; electronic means 130 , 131 and 132 of generating from said sinusoidal signal:
a first periodic synchronization signal being used as a timebase reference, said signal having a first repetition frequency, said signal supplied to an electronic output called a reference output 142 ; a plurality of second periodic synchronization signals, said second signals being offset by a programmable time relative to the first synchronization signal, said second signals being supplied to electronic outputs called programmed delay signal outputs 143 ;
an internal clock 133 emitting an internal clock signal oscillating at a second frequency roughly identical to the first frequency; electronic security management means 130 , arranged so that said internal signal replaces the external clock signal in the event of loss of the latter.
means 120 of generating a second external synchronization clock signal having a frequency identical to the first external clock signal, said signal being supplied to an electronic output called a clock output 141 .
electronic interface means 31 with a control microcomputer 3 , said microcomputer making it possible to control and program all or some of the functions of the device.
electronic triggering means for synchronizing certain functions of the device from at least one external signal, said signal being supplied to an electronic input called a “trigger” input 144 .
control means for delivering control signals for electronic devices or for electromechanical devices 60 or for receiving control signals coming from security systems 61 , said signals being delivered to electronic control outputs 145 .
A certain number of electronic or optoelectronic instruments or systems, such as pulsed lasers, deliver a very high-stability clock signal. This clock signal is used to synchronize the various components of the device to be synchronized.
The main function of the electronic means 130 , 131 and 132 is to generate from the clock signal the synchronization signals S SYNC . The core of these electronic means is formed by a programmable digital component 130 which can be of the FPGA (Fast Programmable Gate Array) type. This digital component generates:
a first periodic synchronization signal S 0 being used as a timebase reference, said signal having a first repetition frequency, said signal supplied to an electronic output called a reference output 142 . a plurality of second periodic synchronization signals S SYNC , said second signals being offset by a programmable time δ M relative to the first synchronization signal S 0 , said second signals being supplied to electronic outputs called programmed delay signal outputs 143 , said second signals having second repetition frequencies.
The synchronization signals S 0 and S SYNC take the form of identical temporal pulse trains, each pulse having the form of a crenellation, the rising edge M and the falling edge D of said crenellation being offset by a first time δ M and a second time δ D programmable relative to the rising edge of the corresponding crenellation of the first synchronization signal S 0 taken as a reference. The time T SYNC separating two pulses is equal to the inverse of the repetition frequency f SYNC of the synchronization signal S SYNC . This repetition frequency f SYNC is adjustable according to the use of the synchronization signal.
The programmable digital component 130 operates at the clock frequency and cannot deliver signals with a temporal resolution greater than the period of said clock frequency. Thus, if the clock frequency is 100 megahertz, the intrinsic resolution of the programmable digital component is 10 nanoseconds. To obtain lower temporal resolutions, there are programmable delay lines 132 at the output of the programmable digital component 130 , each of the second synchronization signals S SYNC being taken from these delay lines. There are thus obtained temporal rising and falling edge accuracies of the crenellations well below the temporal period of the external clock. With the preceding example, it is possible to obtain temporal resolutions of the order of 250 picoseconds with an average uncertainty, also called “jitter”, of 50 picoseconds.
For reasons of user convenience and ergonomics, the various functions of the device can be monitored by a microcomputer 3 by means of electronic interfaces 31 represented symbolically by the double arrow in FIG. 1 . These electronic interfaces 31 can be simple electronic links or be defined according to an electronic standard for the exchange of data between electronic devices such as, for example, the RS 232 standard. The control and monitoring software can be developed using specific software such as measuring instrument monitoring software known by the brand name LABVIEW developed by National Instruments. It is advantageous, when the synchronization device is no longer being monitored by the microcomputer 3 , for all the programmed parameters, in particular the various delays governing the synchronization signals, to be retained such that the synchronization device can operate independently. To this end, the programmable digital component has an electronic memory 131 .
The synchronization device also comprises an internal clock 133 emitting an internal clock signal oscillating at a second frequency roughly identical to the first frequency and first electronic security management means incorporated in the programmable digital component 130 , so that said internal signal replaces the eternal clock signal if the latter disappears. This internal clock is taken from a tunable oscillator which can, for example, be a quartz crystal oscillator.
The operating protocol of the security device according to the invention is described in the diagram of FIG. 2 .
The various steps of the protocol are as follows:
The synchronization device delivers an external clock signal formatted and taken from the electronic device 112 . This signal is examined by electronic means. The examination of the signal is symbolized by the lozenge entitled “SIGNAL”. if the signal is correct, of course, the device continues to operate on the external clock, as symbolized by the “YES” output from the “SIGNAL” lozenge; if the signal is not compliant, as symbolized by the “NO” output from the “SIGNAL” lozenge, the protocol moves on to the next step. The security device then activates three functions symbolized by the rectangles entitled: “PARTIAL STOP”, “CLOCK ACTIVATION” and “DISPLAY”, which correspond to the following tasks:
“PARTIAL STOP”: the devices presenting a danger or likely to be damaged by a prolonged stoppage are switched off; “CLOCK ACTIVATION”: the internal clock is activated and replaces the external clock so that the synchronization signals essential to the correct operation of the system are again activated correctly; “DISPLAY”: failure messages are displayed on the synchronization device itself via indicating diodes, or on the monitoring microcomputer.
The next step entitled “LOOP” terminates the system securing step; The next step entitled “EXT. CLOCK CORRECT” verifies that the external signal is restored. If not, the device returns to operating on the external clock signal, as symbolized by the “YES” output from the “EXT. CLOCK CORRECT” lozenge, to the rectangle entitled “RETURN OF EXTERNAL CLOCK”; otherwise, the protocol moves on to the next step; The next step entitled “LIMIT TIME” verifies that the failure time of the external clock signal is less than a predetermined time.
In the case where the failure time is greater than or equal to this value, as symbolized by the “YES” output from the “LIMIT TIME” lozenge, all the components of the system are stopped, as symbolized by the rectangle entitled “TOTAL STOP”. Otherwise, the external clock signal is tested again after an incrementation time, as symbolized by “INCREMENTATION” in the diagram, until either the clock signal is restored, or the maximum duration of the failure time has elapsed.
As a nonlimiting example, FIG. 3 illustrates a system comprising a synchronization device 1 according to the invention. The device requiring synchronization signals is a laser subsystem emitting ultra-brief pulses. The emitted laser beam 50 is symbolized on FIG. 3 by a double arrow. The subsystem comprises in turn:
an optical oscillator 40 delivering laser pulse trains. Normally, the duration of the pulses is of the order of a few hundred femtoseconds and they are emitted at high repetition frequency, the order of magnitude of this first frequency is a few tens of megahertz. This repetition frequency is of very high stability; a first optical device 41 with diffraction array, also called “stretcher”, for temporally expanding femtosecond pulses. The duration of the pulses is thus multiplied by a factor of between 1000 and 10 000. By thus expanding the pulse, its peak power, which is considerable at the subsystem output, is correspondingly diminished. It can then be amplified greatly in complete safety for the various optical elements of the subsystem; a first amplifier called a regeneration amplifier 42 for supplying from the pulses taken from the “stretcher”, pulses in a determined optical mode having a higher energy. These pulses are delivered with a low repetition frequency, of between 1 hertz and 500 kilohertz; a Pockels cell device 43 making it possible to limit the noise of the pulses by strictly limiting their temporal duration; a laser pulse preamplification 44 and amplification 45 assembly; finally, a second diffraction array device 46 , also called “compressor”, enabling the temporal compression of the pulse so as to return it to its original temporal duration and so increase its peak power.
Of course, depending on the requirements, this subsystem can contain fewer optical elements, the Pockels cell device is not, for example, absolutely necessary. The subsystem can also include other optical elements, it can also have an amplification channel or several channels arranged in parallel.
In order to have geometrical, photometric and spectroscopic data and characteristics on the emitted pulses, samples are taken at various places on the laser subsystem. These samples are taken by means of semi-reflecting blades 47 placed along the optical beam 50 and the duly sampled light beams are sent, for example, to measurement photodiodes 2 , 22 and 24 , ultra-high-speed cameras, called “streak cameras” 21 and 23 , oscilloscopes, and so on. Thus, it is possible to send to the photodiode 2 a part of the laser pulse train taken from the optical oscillator 40 . The electrical signal taken from said photodiode is then supplied to the clock input 140 of the synchronization device 1 according to the invention. From this signal, the synchronization device 1 delivers:
a first periodic synchronization signal S 0 being used as a timebase reference, said signal having its own repetition frequency. Said signal is supplied to an electronic output called a reference output 142 and controls the triggering of the first amplifier called the regeneration amplifier 42 by means of a trigger device 25 ; a plurality of second periodic synchronization signals S SYNC , said second signals being offset by a programmable time relative to the first synchronization signal and also having programmable repetition frequencies, said second signals being supplied to electronic outputs called programmed delay signal outputs 143 and controlling the various optical elements of the subsystem by means of trigger devices 26 and 27 .
The synchronization device 1 also has control means making it possible to deliver control signals for electronic devices or for electromechanical devices 60 or to receive control signals coming from security systems 61 , said signals being delivered to electronic control outputs 145 .
All the parameters of the synchronization device are managed by means of a microcomputer 3 via an interface 31 represented by a double arrow in FIG. 3 .
In the event of failure of the oscillator, the external clock signal disappears. In this case, the security device is activated. The internal clock replaces the external clock to continue activating certain components. They are thus kept at temperature. Other components, like certain amplifiers, are disconnected to avoid an abnormal overheating of their amplification bar. | An electronic device for generating secure synchronization signals operating with an external clock emitting a first frequency signal is such that for very high resolution synchronization signals, the temporal accuracy of the signals is less than a nanosecond, thereby enabling different elements of a laser pulse chain to be synchronized. The device is provided with securing means having an internal clock emitting an internal clock signal oscillating at a second frequency roughly identical to the first frequency, wherein electronic security management means is arranged so that the internal clock signal replaces the external clock signal and security measures are triggered when the external clock signal is lost, thereby causing the partial or complete stop of the device to be synchronized. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and a device for applying prestressed, tension-proof reinforcing strips to constructions, the strips being fixed to the construction with an adhesive.
2. Description of Related Art
For many years, both research and practical work have been done to find a way of strengthening steel concrete constructions after completion by applying an additional reinforcement. The beginnings of this technology are described in a report by J. Bresson entitled “Nouvelles recherches et applications conçemant l'utilisation des collages dans les structures Beton plaqué”, Annales ITBTP No. 278 (1971), Série beton, Beton armé No. 116. The technique dates back to the 1960s. Bresson concentrated on research into the bonding stresses in the vicinity of the anchorages of lamellar steel strips bonded to constructions with adhesive. One advantage is that over the last 25 years, engineers have been able to reinforce existing steel constructions such as bridges, bed-plates, overhead plates, longitudinal supports and the like by subsequently applying lamellar steel strips with adhesive. The reinforcing of concrete constructions by applying lamellar steel strips using e.g. epoxy resin adhesives is now considered a standard technology. Depending on the particular case in hand, the purpose of such a reinforcement is to: increase the working load and alter the static system by removing supporting elements such as pillars, or by reducing the supporting function of such elements and strengthen elements at risk from fatigue stress, increase rigidity compensate damage to the support system or renovate existing constructions, and effect post-construction reinforcement in the event of faulty calculation or execution of a particular construction
Post-construction reinforcement by means of applying lamellar steel strips with adhesive has been successfully used on numerous constructions, as described in, for example: Ladner, M., Ch.: “Geklebte Bewehrung im Stahlbetonbau”, Swiss Federal Laboratories for Materials Testing and Research (EMPA) Dübendorf, Report No. 206 (1981); “Verstärkung von Tragkonstruktionen mit geklebter Armierung”, Schweizer Bauzeitung, special article in the 92nd year, volume 19 (1974); “Die Sanierung der Gizenenbrücke über die Muota”, Schweiz. Ingenieur & Architekt, special article in volume 41 (1980).
These conventional methods of reinforcement are, however, associated with certain disadvantages. Lamellar steel strips can only be supplied in short lengths, and hence only relatively short strips can be applied. This means that where there are lengthy spans, joints between the lamellae are unavoidable, thereby inevitably leading to potential weak spots. Furthermore, handling heavy lamellar steel strips on a building site is an awkward matter, and can cause considerable technical problems in the case of high-level constructions, or constructions which are otherwise difficult to access. In addition, there exists a risk of the steel rusting on the underside of the strips, even if corrosion protection treatment is carefully accomplished, i.e. of corrosion on the contact surface between the steel and the concrete, which can result in the strip becoming detached, and thus a loss of the reinforcement.
In the publication by U. Meier entitled “Brückensanierung mit Hochleistungs-Faserverbundwerkstoffen”, published in Material+Technik, 15th year, volume 4 (1987), and in the dissertation by H. P. Kaiser, Dissertation ETH Zürich (1989), the proposed remedy is to place the lamellar steel strips with carbon fibre reinforced epoxy resin lamellae. Lamellar strips made from this material are characterized by a low bulk density, very high strength, excellent endurance properties and outstanding resistance to corrosion. Instead of heavy lamellar steel strips one can, therefore, also use light, thin, carbon fibre reinforced plastic strips which can be transported to the construction site on virtually endless reels. Practical tests have shown that carbon fibre lamellae of 0.5 mm thickness can absorb the same amount of tensile force as the yield strength of a 3 mm thick FE360 steel strip.
Hence post-construction reinforcement with carbon fibre lamellae fixed directly onto the construction by means of adhesive is already a state-of-the-art technology. The method involving reinforcement with steel lamellae has now largely been replaced by the method whereby the construction is reinforced with non-prestressed carbon fibre lamellae.
It has proved advantageous, particularly when using fibre composite lamellae of the type suggested in ETH Dissertation No. 8918, such as e.g. carbon fibre lamellae, to additionally prestress these lamellae disposed on the concrete construction part, thereby improving the utility of the part and preventing the lamella from shearing off as a result of shear fractures in the concrete in the tension zone. The enormous elastic extensibility of carbon fibre lamellae represents a big opportunity for the aforementioned prestressing operation. The large elastic extensibility and the modulus of elasticity, which is adjusted to the particular circumstances, have a positive impact on prestress losses due to shrinkage and creep.
French Patent Reference 2,594,871 disclosed a method whereby a prestressed strip is applied to the structure to be strengthened, namely to reinforced concrete, and bonded to this structure with adhesive. During the process the strip is prestressed until the adhesive hardens. The device shown in FIGS. 6 and 7 for executing this method is merely a strap held in place by a metal plate, which strap is used to hold the strip in place. This presupposes the availability of rigid anchorage points for attaching these straps, but these are not, however, always provided in practice, and are not disclosed in French Patent Reference 2,594,871. Furthermore, the method disclosed in that document does not allow for the strip to be pressed against the structure at the same time as the bonding process, as is required to achieve reliable bonding.
One remaining difficult point is therefore the problem of anchoring the carbon fibre lamellae during the prestressing process, given that prestressing forces are of several tens of thousands of N. These enormous forces have to maintain the lamella to be applied under tension against the construction itself, at least until the adhesive has hardened completely.
SUMMARY OF THE INVENTION
One object of this invention is to provide a method for applying tension-proof reinforcing strips to constructions which, irrespective of the availability of anchoring points on the construction for absorbing stressing forces, will allow the reinforcing strip to be prestressed and then applied, and which is reliable, simple and inexpensive to use. Another object of this invention is to provide a compact, simple, reliable device for executing this method, which is also inexpensive to manufacture.
This object is achieved with a method for applying prestressed, tension-proof reinforcing strips to constructions in which the strip to be applied is prestressed, pre-treated with adhesive and then positioned up to a construction and bonded to this structure. The method of this invention requires no anchorage points on the construction for absorbing stress forces because it is positioned up to the construction by a device on which the strip can be stretched under prestressing force, such as a device used to press the strip against the corresponding, pre-treated part of the construction until the adhesive hardens. The task is also solved with an apparatus for executing this method, as described in this specification and in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings show preferred embodiments of an apparatus which will be used to explain in detail the way the apparatus operates, and the nature of the method for applying the tension-proof reinforcing strips. The drawings show:
FIG. 1 a is a schematic view of a stressing mechanism of a device prior to stressing a tension-proof strip;
FIG. 1 b is a schematic view of the stressing mechanism of the device during the process of stressing the tension-proof strip;
FIG. 2 is a side view of a stressing mechanism of the device, shown in detail;
FIG. 3 is a schematic side view of an entire device, with a prestressed reinforcing strip, mounted on a construction just before the reinforcing strip is applied to the construction;
FIG. 4 a is a schematic side view of an entire device, during the process of applying a discontinuously stressed strip, with the two heating/press-on elements moved from a center zone towards ends of the stressing device;
FIG. 4 b is a schematic side view of an entire device, during the process of applying a discontinuously stressed strip, with one heating/pressure element moved from one end of the stressing device to the other end; and
FIG. 4 c is a graph showing the development of the degree of prestressing along the fully applied discontinuously stressed strip.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 a shows one basic principle of the device or apparatus of this invention. The device comprises a curved, rotatable surface 14 , which is formed here by the outer surface of wheel 2 . One end of the reinforcing strip to be prestressed, namely the fibre reinforced plastic lamella 9 , is attached to the surface 14 . The other end of plastic lamella 9 can be tension-proofly anchored by some other means, or in exactly the same way as shown. In the example shown, a holding device 18 is provided on the curved surface 14 , i.e. in this case to the outside of the wheel, to which strip 9 can be fixed with clamps and at least one screw 10 . The plastic lamella 9 is a strip which can be a few centimeters wide and about one millimeter thick. The curved rotatable surface 14 , i.e. the wheel 2 in this example, is connected to a lever 4 which can be pivoted around the axis of the wheel, clockwise in this drawing, to rotate the wheel 2 and the curved surface 14 with it.
FIG. 1 b shows this part of the device during the process of rotating wheel 2 , whereby lever 4 is subjected to a force F that is as tangential as possible to wheel 2 . This winds reinforcing strip 9 around wheel 2 ; in the embodiment shown, the reinforcing strip 9 is wound around curved surface 14 by 270°. The high tensile force also has an impact on the static friction of strip 9 against curved surface 14 , because a very high normal force takes effect. Tests have shown that if the strip is only wound around half the circumference, i.e. 180°, the effective tensile force at the end of strip 9 is reduced by as much as a quarter in the direction of the strip 9 . This knowledge forms one basic concept of the construction of the device and the method according to this invention.
FIG. 2 shows an enlarged view of the actual stressing unit. In this case, curved surface 14 is formed by wheel 2 , which is rotatably mounted on a frame 12 . An adjustable fixing device 3 is provided on frame 12 , for the purpose of provisionally fixing the entire device to the construction 7 to be reinforced. Lamella 9 , or strip 9 , is introduced into the device and is wound around a contact angle of 270° by rotating curved surface 14 . Bolt 11 locks lever 4 in discrete positions of wheel 2 on frame 12 . The prestressing force can be maintained by means of a locking device 5 . The elements required to apply the prestressing force, e.g. a hydraulic pistoncylinder unit or a screw link actuator, may be part of the stressing unit, or may alternatively be add-on modules, so that they only need to be mounted on the device as required and then removed again after the prestressing process. The frame 12 of the stressing unit and stressing mechanism is connected to a connection support 1 via mounting flange 8 . The stressing device is attached to the construction 7 requiring reinforcement via two fixing devices 3 , which are connected to the stressing device so that they are vertically displaceable and lockable. This vertical height is only set after the stressing device contacts construction 7 , so that a perfect contact and positioning can be produced. On at least one side of the stressing device the means of attaching the device must be contrived as a longitudinally displaceable movable bearing in order to be able to accommodate any linear expansion of the stressing device.
In addition to providing a means of prestressing strip 9 , the device also enables the strip 9 to be attached to construction 7 and then held in the prestressed state until the adhesive hardens. The entire device required for this purpose is shown in FIG. 3, which is a side view. This device comprises a rigid steel or aluminum support 1 , an extruded or welded box girder, a framework or a wound fibre reinforced plastic support which is fixed between two stressing units 15 , 16 as described above, and acts as a means of mounting the units opposite each other. The curved surface 13 at one end can be rotated, while the curved surface 14 at the opposite end can also be rotated, but does not have to be rotatable. In this drawing, the ends of the overall prestressing device have the adjustable fixing devices 3 used to attach it provisionally to construction 7 . At least one fixing device 3 is contrived as a longitudinally displaceable movable bearing.
FIG. 3 shows the stressing device immediately before strip 9 is applied to construction 7 . Placed between lamella or strip 9 and support 1 of the prestressing device there is an air bag 6 or extensible air hose, which, when air pressure is applied, exerts a uniform pressure across the entire surface of the lamella or strip 9 in contact with the construction.
To apply a lamella 9 , the device is first loaded with a strip. The strip or lamella 9 is first tangentially contacted with the curved surface on the two wheels 2 of the device which is e.g. lying on the ground, and then fixed to both surfaces 13 , 14 by means of holding devices 18 , as shown in FIG. 1, and the associated clamping screws. Curved surfaces 13 , 14 can be surface treated, or suitable films can be inserted between them to adjust the friction coefficient between curved surfaces 13 , 14 and lamella 9 over large areas and, with it, the residual prestressing force at the holding device 18 , as shown in FIG. 1, of lamella 9 after stressing. The two curved surfaces 13 , 14 are rotated by hand or with a tool until lamella 9 is wound around a certain contact angle, thereby developing sufficient static friction on the two curved surfaces 13 , 14 so that by rotating one of surfaces 13 or 14 even further, lamella 9 can be prestressed. The lever is provisionally locked in an ideal position with a bolt 11 , as shown in FIG. 2, and then the stressing device for applying the necessary prestressing force is installed. This force can be applied hydraulically or pneumatically by an appropriate piston-cylinder unit, or by means of a screw link actuator, or simply by means of a screw. After applying the prestressing force, the stressing device is removed from the device, unless the stressing device is designed as part of and rigidly connected to the overall device. Rotatable curved surfaces 13 , 14 are locked in place with locking device 5 so that the applied prestressing force is reliably maintained. Adhesive is then spread over the appropriate points of prestressed lamella 9 in the desired thickness. The device with the prestressed lamella 9 on it is then brought up to construction 7 . For this purpose a lifting appliance, preferably a hydraulic excavator with a fully rotatable grabber, a crane or a hydraulic lifting platform is used to bring the device up to construction 7 and the pre-treated concrete surface to be reinforced, and positioned in such a way against the construction strip 9 is located in the desired position, where it runs in the right direction. The device is then provisionally fixed to construction 7 by means of the two vertically adjustable fixing devices 3 . Fixing devices 3 are then adjusted so that lamella 9 lies flush against the construction. Finally, compressed air is applied to the air bag 6 or air hose associated with the device so that lamella 9 is pressed evenly against construction 7 over the whole of its area to be bonded to construction 7 . Lamella 9 is therefore pressed against construction 7 in a prestressed state until the adhesive is completely dry. If required, the tension in lamella 9 can be measured with strain gauges applied to lamella 9 . In the event of large fluctuations during the hardening period cause by the change in temperature between day and night, a heater disposed in the support of the prestressing device can be used to regulate its temperature with a view to compensating changes in temperature and thereby avoiding any dilatation. It is only when the adhesive is completely dry that the end anchorages of lamella 9 are moved into position and the prestressing force on at least one side of the device is slowly reduced and the device is relieved. Lamella 9 is now cut through at the ends of the bonded areas. As soon as this has been done, fixing devices 3 can be detached, and the device can be moved away again from construction 7 by means of the crane or excavator.
A slightly different form of the same device can also be used in a slightly different way for reinforcing with discontinuously prestressed lamella 9 . In this case the lamella 9 applied to the construction is not evenly prestressed along its full length, but is less prestressed at its ends, or indeed not at all, while other zones, usually in the middle of the lamella 9 , but in other areas as well, are prestressed to a maximum. This distribution of prestressing force is achieved by creating a local bond between construction and lamella 9 in small areas and then subsequently adjusting the prestressing of the lamella 9 areas yet to be bonded. In each already bonded area, the lamella 9 therefore stores the degree of prestress prevailing when the bond was initially produced.
FIG. 4 a shows the device for applying a discontinuously stressed lamella. There is no air bag 6 . Disposed between support 1 and the stressed lamella 9 there is at least one heating/press-on element 19 which can be displaced in the longitudinal direction of the device. In the example shown there are two such heating/press-on elements 19 . These heating/press-on elements 19 can be moved along the entire length of the support either by hand or preferably by some motorized means. They may be driven by an electric motor for example, and displaced along a rail and, for example, a toothed rack on the support. Heating/press-on elements 19 could also be pulled across support 1 along a slide rail by means of e.g. an electric rope haulage system. They are equipped with electric heaters and the heating and drive functions can preferably be remote controlled. Each element 19 heats up the section of lamella with which it is in contact, and presses it against construction 7 . The heat produces or accelerates the bond between the section of lamella 9 and the construction. In the example illustrated, these heating/press-on elements 19 are moved outwards from the center of lamella 9 . While these elements 19 are slowly moved outwards, the prestressing force of lamella 9 is reduced by the required amount, either continuously or in discrete steps. Lamella 9 therefore ends up securely bonded to construction 7 with varying prestressing forces over its entire length, so that the prestressing force is distributed exactly as required over the entire length of the lamella 9 .
The same distribution of the prestressing force in the lamella 9 can also be achieved by using just one heating/press-on element 19 , as shown in FIG. 4 b . Here, this heating/press-on element 19 is moved from one end of the stressing device to the other. Starting from a minimum value, the prestressing force applied to lamella 9 is increased continuously or in steps up to the maximum value, while heating/press-on element 19 is simultaneously displaced, in this case from left to right, until heating/press-on element 19 reaches the middle of lamella 9 , for example. The prestressing force is then reduced to the required minimum value, while heating/press-on element 19 is simultaneously displaced towards the right of the drawing to the other end of lamella 9 .
The stressing force applied to lamella 9 is applied and altered with precisely positionable and controllable hydraulic piston-cylinder units or screw link actuators. The precise degree of prestressing is measured with strain gauges positioned on the lamella 9 , or by means of an integral force measuring device in the prestressing device. Heating/press-on elements 19 can be displaced by hand, or preferably automatically along the entire length of the section being stressed. It is advantageous if the entire operation can be remote-controlled, especially when prestressed strips have to be attached to bridges at great heights using cranes or excavators, for example. The same applies when working with hollow structures, where the strip has to be contacted with the construction from the inside, with the result that access is restricted.
In those instances in which the prestressing force applied to the strip 9 has to be altered while the strip 9 is bonded, the two fixing devices 3 of the prestressing device both have to be contrived as longitudinally displaceable movable bearings so as to avoid a static indeterminacy of the attachment of the stressing device to the construction.
FIG. 4 c shows an example of the possible development of the degree of prestressing in lamella 9 . In this case, lamella 9 has an identical minimum prestressing force, Fmin, at its ends, which increases continuously towards the center of lamella 9 until it reaches a maximum prestressing force Fmax. The development of the prestressing force applied to lamella 9 over its entire length can, however, be adapted to suit each particular application. | Lamellar, fibre-reinforced plastic strips can be used to reinforce a linearly expanded or flat construction part having a support function against any bending stress to which it is exposed. The strips are usually applied to the construction from the outside, or from the inside in the case of hollow structures, and fixed by an adhesive. The lamellar strips are pretensed with a tensioning device, treated with adhesive in a pretensed state, and then moved to the area to be treated together with the tension device. The tension device is provisionally fixed to the construction with displaceable fixing devices and pressed against said construction. Thereafter the lamellar strips are pressed against the construction by means of an air bag or air hose until the adhesive has hardened. | 4 |
DISCUSSION OF RELATED ART
[0001] Vessels used in life science research labs are traditionally formed of glass. These traditionally glass containers are susceptible to cracking, exploding, shattering and can cause injuries due to the razor sharp edges of the pieces of broken glass during normal utility. A variety of specialized and general laboratory bottles have been invented including the Erlenmyer flask, the beaker, the Fembach flask, the volumetric flask, the jar, wide mouth bottle, narrow mouth bottle, square bottle, and dilution bottle. Many of these vessels are formed with various plastic resins, however due to inertness the glass vessels remain the chosen container for microbial culture media preparation by terminal sterilization.
[0002] Until now, glass containers have been the primary vessels that have been used for terminal sterilization of culture media and related biological fluids with fully engaged/tightened cap on the sterilization vessels as they can withstand the pressure and temperature associated with the autoclaving of closed container, however if there is a weak spot in glass, the bottles build up an aerosol pressure that can cause the bottle to burst, and spill out the contents as well as cause significant damage especially if failure occurs near operators or laboratory personnel. Exploding fluids that have been raised to temperatures of 121 C at 15 PSI cause severe burns.
[0003] Fluids, such as culture medium for growing a wide variety of microbial organisms are prepared in such vessels. Such fluids are made from powder that is hydrated and then sterilized in an autoclave by subjecting the content and the vessel to a temperature of 121 C at 15 PSI for 30 minutes to 45 minutes. The fluids are usually sterilized in glass bottles with the cap closed allowing the outside of the bottle to be sterilized as well as allowing the inside of the bottle and its content to be sterilized. When using a plastic bottle, a user commonly loosens the cap sterilizing the outside of the bottle as well as the inside. The user must then cool the bottle content before fully engaging the cap for an airtight seal. Once the sterilization cycle is completed the vessels are removed from autoclave to allow a normalization of content reach room temperature so the operator can move the vessels. While the content is cooling, the loose cap can allow the transfer of air and microbes may enter due to exchange of air into the contents of the plastic bottle. Contamination is costly in time and money as the contents cannot be used, and are deemed unacceptable for laboratory work. It defeats the purpose of sterilization and the process has to be repeated again.
[0004] Laboratory bottle made of plastic resin such as a polycarbonate LEXAN™ made by GE is shatter proof and does not explode causing damage to the user. Such plastic used must be extremely durable, resistant to leaching, inert to most chemical reactions, resistant to staining, resistant to retaining odors and must be able to withstand temperatures from −135° C. (−211° F.) to 135° C. (275° F.). This temperature and pressure is enough to cause shattering of glass bottles and implosion of ordinary plastic bottles. Polycarbonate plastic has been used for laboratory bottles. Because glass bottles can break and are not as safe as plastic bottles, laboratory consumers have used plastic bottles where plastic bottles can be used. Plastic bottles continue to have limitations such as loss of strength at high temperatures and therefore have not been used in the production of culture media through terminal sterilization. The prohibitive cost of such plastic containers have also forced the suppliers of media to use glass that is cheaper, but much heavier and less safe then other alternative.
[0005] The vessel closure is typically made with virgin, high-temperature polypropylene (PP). The cap is liner-free relying on a seal ring molded inside the cap and fitting tightly against the bottle neck to insure a leak-proof system. Threads on both bottle and cap are usually continuous and straight-shouldered, semi-buttress threads to again insure a leak-proof system. The base is usually broad and stable so that the bottle will not tip over during fill. The base often includes molded text information such as resin code, a recycling code, and the fill capacity. The typical wall thickness is uniform having beveled edges.
[0006] Plastic bottles manufactured according to current methods have a number of flaws. Many plastic bottles must be cleaned and but cannot be autoclaved during laboratory procedure. Plastic bottles can collapse if they are autoclaved with the cap sealed. Also, the handling of the cap by a user can contaminate the contents. A biology lab is a fertile environment for microbes, therefore microbial contamination is a very real and prevalent occurrence. When a user places the cap on the laboratory table, a variety of contaminants can enter the bottle through the cap.
[0007] Presently, the industry lacks a single, universally safe, chemically inert, shatterproof, implosion/explosion resistant, non-hazardous, multipurpose laboratory vessel for microbial media preparation, terminal sterilization, performing suspension culture, media packaging, media storage, contamination control, and transportation of sterile media fluids.
OBJECTS OF THE INVENTION
[0008] The first object of the invention is to use a safe and multipurpose vessel that allows for terminal sterilization without implosion or explosion when the cap is secured. The second object of the invention is to deter contamination during normalization of temperature after sterilization. The third object of the invention is to create a safe, shatterproof, implosion resistant, explosion proof, non-hazardous, multipurpose laboratory vessel for microbial culture media preparation, terminal sterilization, suspension culture, media packaging and storage, contamination control, and safe, leakage-free transportation of sterile media fluids.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a side view of the first embodiment in closed position.
[0010] FIG. 2 is a side view of the first embodiment in open position.
[0011] FIG. 3 is a perspective view of the second embodiment in closed position.
[0012] FIG. 4 is a perspective view of the second embodiment in open position.
[0013] FIG. 5 is a bottom view of the second embodiment in closed position.
[0014] FIG. 6 is a top view of the second embodiment in closed position.
[0015] FIG. 7 is a top view of the second embodiment in open position.
[0016] FIG. 8 is an isometric view of the third embodiment in closed position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] The present invention can be formed in a variety of shapes and sizes. Figure one shows a small bottle having a narrow mouth and small cap. Figure eight shows a larger bottle having a wide mouth and a larger cap with the sidewall bearing a swirl design.
[0018] The bottle is created by an injection blow molding process. The injection blow molding process begins with an injection step where plastic is injected into an injection mold, a blow mold step where plastic is injected into a blow mold and a final step where the finished product is ejected from the blow mold.
[0019] The shoulder arc is the junction of the shoulder and vertical cylindrical portion of the bottle. The shoulder arc preferably has a radius. The base arc preferably has a radius also and is a junction of the vertical cylindrical portion of the bottle and the base. The base is commonly circular in shape having a base rim.
[0020] Injecting plastic from the container base into a first mold or preform mold forms a preform piece having an annular bump around the shoulder and annular bump or protrusion around the base. The bump is gradual and appears smooth to the touch presenting a momentary thicker cross section. The annular nature of the bump allows a continuous ring around the shoulder and base arc of the preform piece. The protrusion can be formed on the inside or the outside of the piece. It is preferred to form the bump on the inside of the pre form piece. The shape of the protrusion is shallow and is positioned so that the final arc of the shoulder and arc of the base is slightly thicker by approximately one-tenth of an inch.
[0021] Alternatively, injecting plastic from the container base into a first mold can form a piece having an annular bump around the neck and base arc instead of the shoulder and base arc. Here, the shape of the protrusion is shallow and is positioned so that the final arc of the neck and arc of the base is slightly thicker by approximately one-tenth of an inch.
[0022] The neck arc is the area where the vertical wall of the neck meets the angle wall of the shoulder. The shoulder arc is the junction of the shoulder and vertical cylindrical portion of the bottle. The shoulder arc preferably has a radius. The base arc preferably has a radius also and is a junction of the vertical cylindrical portion of the bottle and the base. The base is commonly circular in shape having a base rim.
[0023] After the protrusion is placed on the preform mold, more than a single trial will be necessary, but excessive experimentation would not be required. Numerous factors complicate and prevent a mold designer from reaching a perfected product in the first trial. Depending upon the shape of the final product, the mold designer may require a number of trials and wasted material before perfecting the production mold. Phase change and crystallization induces substantial deformation and residual stresses that weakens the final bottle and modifies its thickness profile. During the blowing phase, the preform plastic part is blown like a balloon to final dimensions. Viscoelastic effects including strain hardening limit stretching in certain locations. Plastic coming in first contact with the mold deforms less. Thus, final thickness requires considering the initial thickness of the preform piece in addition to related industry variables. Electronic computer calculations of blow molding simulation can account for whether parison or preform mold is flying in open room or whether it is in contact with a mold. Numerical algorithms allow complex geometry calculation shortening the number of trials required for practicing the invention.
[0024] Blowing the preform plastic into a second mold by injecting air through the opening of the preform mold forms a finished plastic container 10 shaped with an annular protrusion around the shoulder arc 150 and annular protrusion around the base arc 160 forming a thicker wall at the base and shoulder before ejecting the finished plastic container from the second mold. The preform piece produced can be air blown and stretched to accommodate from 250 ml to 1250 ml of volume by varying the diameter.
[0025] The wall of the polycarbonate bottle is not uniform and ranges in thickness from 7 mm at the side wall 140 to 9 mm at the neck arc and base arc areas allowing a user to close the cap forming an airtight seal inside the chamber and allowing a user to autoclave the bottle without risk of implosion for sterilizing the outside surface of the bottle. This ratio can be further improved by changing the topography of the vessel such as changing the shape from round to octagonal of adding baffles or wavy patterns.
[0026] A neck ring 220 insures security of shrink-wrapped seals. The neck ring has a smooth interior so there is no fluid entrapment and no back-flow contamination. The bottle holds a tether 65 at a first end of the retaining neck ring attaching to the retaining neck ring rim provided on the bottle. The tether 65 has a second end attached to the cap 120 of the bottle. The plastic cap is tethered to a tether ring 99 , FIG. 4 , FIG. 1 , FIG. 2 . that can fit over the neck ring of the bottle. The tether ring is elastic so that it can stretch over the neck ring 220 of the bottle. The tether 65 formed as a band terminates at a first end with a plastic cap 120 and terminates at an opposite end with the tether ring 99 . The container can be used for storage in the closed position. The container can also be used to transport contents while the cap is in closed position.
[0027] The loop top tether 65 is a flat band having calibrated stiffness allowing an open cap to rest in open extended position suspended in midair as shown in FIG. 2 and FIG. 4 . The cap can rest without touching the bottle or resting surface such as lab table. The stiffness is not so great as to bias the cap back into closed position. The tether band is formed of a flexible plastic material having a spring force calibrated to hang at the side of the bottle 140 without touching the bottle 140 or table as shown in figure two.
[0028] As shown in FIG. 3 , the cap 120 can cover the neck ring so that the cap is seen while the neck ring is not seen. When a user removes the cap 120 the neck ring 220 is exposed as well as the tether ring 99 . The band 65 has optionally indentations 35 allowing calibration of stiffness.
[0029] Parallel grooves 35 formed in the outside of the tethered band 65 can be used to change the stiffness and resilience of the band as seen FIG. 5 and FIG. 6 . Additional grooves allow a less stiff band and can be matched with caps so that heavier caps receive stiffer bands.
[0030] The polycarbonate container does not leach or add contaminants into the contents during the autoclave process. The culture media remains inside the container during the autoclave process. The culture media is usable for all appropriate microbial culture applications while maintaining sterility. The contents can then be shipped using commercial carriers without concern of leakage or transferring contaminants into or out of the vessel. If the temperature exceeds the norm in the autoclave, or if the autoclave is mis-calibrated, or is opened prematurely causing significant change in pressure the vessel does not explode as it has ample flexibility to distort and stretch.
[0031] The method of using the flask allows a closed system for culturing of microbes in suspension cultures that minimizes the risk of contamination and accidental material failure of the flask. The vessel is an alternative to the Erlenmeyer glass flasks that are used as intermediary vessels after terminal sterilization of fluids used for microbial culture.
[0032] A user dispenses the microbial culture fluid into the vessel. A user does not need to transfer sterile fluids into a new vessel thus preventing contamination possibilities. The microbial culture fluid is dispensed into the container through the opening in the container. The user can hand seal the fluid inside the container by closing the cap. The user sterilizes the culture by autoclaving the flask with contents inside. The user keeps the fluid closed within the container and optionally places a shrink wrap seal over the shrink wrap neck ring. The user can collect a large number of the flasks processed similarly, package them and put them on a pallet for shipping to a second location. The user minimizes washing of glass vessels, and saves considerable time to begin the culture.
[0033] The culture can be prepared shipped and grown in the same vessel. The same vessel again has accommodation for fitting in a shaking incubator for suspension. When the shipment arrives from the first location to the second location, the user can unload the pallets and transport the flasks from the warehouse to the laboratory, without the fear of contamination of the sterile media. If a user accidentally drops one or more of the bottles, the media remains sterile and can be used with confidence. The bottle is shatterproof and can withstand stress of falling from as much as 12 feet. In the laboratory, the user prepares the bottle by removing the optional shrink wrap seal that is fitted over the shrink wrap neck ring. The shrink wrap can be recycled. The user then opens the cap so that the cap hangs from the tether. The tether is calibrated allowing the cap to hang in midair without touching the bottle, or the laboratory bench, leaving the users hand free to perform lab procedure. The user dispenses microbes into the bottle and closes the bottle cap on the bottle. The user can then put the bottle into a shaker device that agitates the bottle and contents for mixing. After mixing, the bottle can be placed into a temperature controlled area allowing microbe growth. After a predetermined time, the bottle can be repackaged. Optionally, a second shrink wrap seal can be fitted over the shrink wrap neck ring. After the bottle is packed, the user can ship the bottle to a second laboratory for collection of microbes of interest and further analysis, Nucleic acid purification, protein purification, gene expression or related studies.
[0034] Finally, terminal sterilization can be performed before disposal of the bottle and contents to eliminate biological hazard. | A plastic lab bottle created by an injection blow molding process comprises the steps of injecting plastic into a first mold from the plastic lab bottle bottom to form a preformed plastic lab bottle; blowing the preformed plastic lab bottle into a second mold by injecting air into the preformed plastic lab bottle through the mouth opening of the preformed plastic lab bottle; ejecting the finished plastic container from the second mold; providing a plastic cap for closing the bottle; and pulling the tether ring over the neck ring of the bottle. | 1 |
This application is a continuation-in-part application which claims priority of and serves as a conversion of pending U.S. Provisional Patent Application Ser. No. 60/061,654, filed Oct. 10, 1997, entitled "Fence Clip Installer", the disclosure of which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, in general, to an apparatus and method for securing fencing wire to a fence post. More specifically, the invention relates to a device for quickly and conveniently installing clips that attach wire strands onto metal fencing posts on farms, ranches, and industrial sites.
2. Related Art
Many agricultural and industrial locations currently use fencing that comprises metal posts for upright members and wire strung horizontally between, and secured to, the posts at one or more levels above the ground. Currently, the standard means for attaching the fence wire to the metals post is a generally U-shaped wire clip 3 with each of its ends curved out in a circular or semi-circular shape. These clips 3 are typically a thick wire of about 6 gauge that is bent by the manufacturer into the U with its "curled" ends 5 lying in generally the same plane as the main body 7 of the "U", as shown in the "prior art clip" of FIG. 10. The standard clip 3 is generally smoothly curved rather than bent at an angle and is about 3 inches long and about 3 inches wide at its widest point. The clips 3 are packaged loose and unattached to each other in boxes or bags, where many of the clips becoming tangled together due to their shape.
A person stringing the fence wire typically carries a bag of dozens or hundreds of these clips with him/her to the fencing site and, each time he needs one or each time his handful of clips runs out, he reaches into the bag to untangle a clip or clips from the jumble. While holding the wire in place against the post, he pushes the individual clip 3 horizontally around the fence post above the wire. He then slips a long nail or other elongated member through one curled end 5 of the clip to engage the end of the clip and then manually twists the end down around the wire on one side of the post, and crimps the clip end onto the wire with a pliers. He then uses the nail to engage the other curled end 5 of the clip and, likewise, to twist it down around the wire on the other side of the post and crimp it with a pliers. He must use considerable strength to twist each end down to crimp the clip around the wire, to pull the clip snug against the post, thus securing the wire tightly to the post to prevent the clip and wire from falling down the post. Most standard metal posts include protrusions running down one side (as in the front of the post in FIG. 1) that form notches, and these notches act as ledges upon which the wire may rest to help prevent it from sliding down the post during installation and after installation Still, the person installing the clip must tighten the clips enough to keep the wire from moving out of the post notches and preferably enough to prevent lateral movement of the wire through the clip after installation.
The standard wire and clip installation procedure is a clumsy and time-consuming procedure, and, therefore, an inefficient and costly procedure. Along a one-mile stretch of fence, a typical 5-wire fence will require about 1650 clips. The person installing the fence must first pound in a post and wrestle with a box or bag of tangled clips. He/she must use strength and manual dexterity to properly position and pull taught the wire, to properly position the clip relative to the post and wire, and then to tighten the clip ends around the wire. This procedure requires a great deal of man-power and is considered a tedious and frustrating job. There is a need, therefore, for an improved technique and apparatus for securing fence wire to the commonly-used metal fence posts.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a quicker and less awkward method for installing fence when using conventional metal fence posts. Another object is to provide an installation tool that gives quick, reproducible, consistent, and reliable results. Another object is to provide an improved clip design and to eliminate the need to untangle individual clips from a mass of jumbled, tangled clips.
The present invention comprises a device for installing clips around a post and wire. The device comprises a tool which holds and manipulates a plurality of clips in an organized fashion in the proximity of the vertical post and transverse wire. The invented tool installs the clip semi-automatically by forcing the clip around the post and then around the wire on both sides of the post. This is preferably done with a movement of one or more handles, or by other convenient, reproducible, and comfortable movement of an actuator such as one or more handles or triggers.
The device is preferably hand-held and may be loaded with a stack of clips that are aligned and temporarily connected together to create a type of "clip cartridge". The device is then used to install that number of clips in the cartridge quickly and consistently without reloading.
The tool has a mechanism to move one clip at a time horizontally toward the post into a "straddling" position, around the post and adjacent to the wire to be fastened. The tool also has a mechanism to then simultaneously bend both ends of the clip down from the plane of the clip to tighten them around the wire. Preferably, these two mechanisms are accomplished by one or more easily-gripped actuating handles manipulated by the user. This way, the tool installs the clip securely around post and wire in one or two smooth operations, without the need for the user to contact or manipulate the clips with his hands after the initial loading of a stack of clips into the tool. The invented tool may also include a system for bracing the tool against the post and/or wire, which may include closing or tightening part of the tool around the post.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of the invented clip installing tool and method, with the tool rear assembly in the back position to open the tool for installation around the fence post.
FIG. 2 is a perspective view of the invented tool of FIG. 1.
FIG. 3 is a top view of the tool of FIG. 1, shown with a stack of clips inserted into the tool, and one clip pushed forward as it would be around a post, prior to crimping.
FIG. 4 is a cross-sectional side view of the tool of FIG. 1, with an arrow showing the forward movement of the bottom clip around the dashed-line fence post, and an arrow showing the downward movement that the stack of clips is to take after the bottom clip is fully forward.
FIG. 5 is a cross-sectional side view of the tool of FIG. 4, with the crimping arm pivoting downward to push the clip end around the wire, herein shown as a two-strand wire.
FIGS. 6 and 7 show two progressive positions of the crimped clip end around the wire, relative to the fence post, with FIG. 6 showing further rotation of the clip end for the tighter, preferred crimping of the wire.
FIG. 8 is a perspective view of a single clip of the invention, as yet unattached from other clips.
FIG. 9 is a perspective view of a plurality of the clips of FIG. 8, connected together by an appropriate temporary adhesive for creating a stack of clips.
FIG. 10 is a top view of a prior art clip.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1-9, there is shown one, but not the only, embodiment of the invented clip installation tool 10, herein also called "the tool" or "the installer", and the method of using the tool. Although the preferred embodiment at the time of filing is herein described, the invention may be altered for manufacturing efficiency and economy and still be within the scope and spirit of the invention.
FIG. 1 suggests how a user may stand comfortably with the tool in his hand, repeatedly operating the tool in a smooth and efficient fashion to install clips at several levels on the post. Before clip installation, the user inserts a stack of clips 14 into the tool. The tool 10 has a receiving cavity 12 or other means for receiving the stack of connected clips 14. The clips 14 lie horizontally in the cavity 12 with the ends pointing forward, which is designated as the left side of FIGS. 1-5.
The user places the tool 10 around the metal fence post 15, through a side opening 17 of about 3-4 inches that allows the tool to lie in a horizontal plane, generally perpendicular to the post, and surround the post on three sides. After placing the tool 10 around the post 15, the tool 10 is positioned so that wire-receiving brackets 19 on each side of the tool receive the single wire or multi-strand wire 21 as it runs laterally and horizontally through the brackets 19.
The user then pulls a first handle, "slide" handle 16 which connects to the rear assembly via first lever system L1, in order to pull the rear assembly 18 forward towards him as indicated by FIGS. 3 and 4. This rear assembly 18 slides forward on the side wall 42 and has two main functions: 1) to close the tool opening 17 relative to its fully opened position in order to grip the post and thus brace the tool against the post, and 2) to move the clip appropriately around the post. The handle 16 and rear assembly 18 accomplish these two above-listed functions as described below.
The rear assembly 18 comprises upper and lower guide assemblies (G1 and G2) which come forward, when the handle 16 is pulled, to receive the rear, V-shaped side of the post in the slots (S) at the front of the guide assemblies, thus gripping the post between the guide assemblies and the support plate 23. The lower guide assembly (G2) comprises an upper plate 27 and a lower plate 29, which are parallel to each other and provide a horizontal space only slightly larger than the thickness of the preferred clip (about 1/3 centimeter) and only slightly wider than the width of the clip. The upper plate 27 has an aperture approximately the size and shape of the clip at the clip's outer perimeter, so that the stack of clips in the clip cavity 12 can rest on the lower plate 29, with the bottom clip sitting in the aperture and on the lower plate 29. Also, there may be a cavity wall 26 with an interior surface slightly larger than, but in the shape of, the outer perimeter of the clip stack, for providing a close-fitting cavity fitting the shape of the clips. Thus, the cavity 12 supports the clip stack, maintains proper orientation of the clips and prevents premature detachment of the clips from each other.
Between the lower and upper plates and behind the bottom clip is the slide plate 20 which is used to force the bottom clip forward. Slide plate 20 has a curved front edge 22 which receives the back end 24 of the bottom clip of the stack. Slide plate 20 is adapted to slide forward and backward between the lower plate and upper plate, guided by the sidewalls 42 and 44. Slide plate 20 may be controlled by a lever assembly L2. The lever assembly L2, which is summarized below, may connect to the lower plate by being bolted to the slide plate through a longitudinal slot in the lower plate.
In use, as the handle 16 is pulled forward, the first lever system L1 pulls the rear assembly 18 forward relative to the wall 42 and relative to the front assembly 43, closing up the opening 17 so that the post is gripped between the support plate and the slots of the guide assemblies, or at least so that the tool is stabilized/braced on the post to prevent tilting and wobbling. Simultaneously, the second lever system L2, which extends between the rear of the wall 42 and the slide plate 20, moves the slide plate 20 forward relative to the moving guide assemblies. This action of the slide plate detaches the bottom clip 25 from the stack of clips, leaving the remainder of clips intact and behind in their resting place on top of the upper plate. Lever assembly L2 comprises generally members 60 and 62 extending from the sidewall 42 to member 64. Member 64 pivots at a pivot point on the bottom of the rear assembly 18. Between the end 65 of the member 64 and the pivot point, the member 64 connects to the slide plate 20 near the proximal end of the slide plate. This way, when rear assembly 18 moves forward, member 64 pivots to push the slide plate 20 forward. The forward movement of the slide plate 20 relative to the guide assemblies, is controlled by the lever assembly L1 and L2 configuration and occurs at a rate and distance that pushes the bottom clip 25 around the post at about the same instant that the post is gripped.
Once the clip is pushed into place around the post, the user then pulls the second handle, the "crimping" handle 30, which actuates two crimping arms 32, 34, one of which is on each side of the tool and hence on each side of the fence post. FIGS. 3 and 5 show how both arms 32, 34 may pivot on a single axle 36, and how the arms pivot downward and backward (right in FIGS. 3 and 5) to contact the clip ends to force the clip ends 38 also down and backward. Thus, the clip ends curve or rotate counter-clockwise in FIG. 5 around the wire. Of particular importance in this invention is that this crimping or "pivoting" means forces the clip ends, which are otherwise generally straight portions of the clip, down out of the generally horizontal plane of the uncrimped clip and the main body of the clip. The crimping means forces the clip ends to pivot backward in a generally vertical plane, that is, generally perpendicular to the plane of the main body of the clip and generally parallel but laterally offset from the longitudinal axis of the clip. As shown in FIGS. 6 and 7, the arms pivot far enough to push the clip end at least close to the horizontal main body of the clip, that is, about 180 degrees. Preferably, the clip end is pushed even further to the position in FIG. 7, that is, greater than 180 degrees, and preferably about 225 degrees.
When the clip is completely installed, the user may let go of the handle 30, which returns it and the crimping arms by spring action to their original position. Then, he may return handle 16 to its original position, which re-widens the opening 17 by moving the rear assembly and slide plate backward away from the post. The tool 10 may then be moved sideways off the post and be moved to another position on the post or to the next post for repetition of the procedure.
Thus, two handles 16 and 30 actuate the two main functions of the tool 10: a) the sliding function, which requires a means for placing the clip around the fence post with the clip end extending forward past the post far enough to eventually extend around the wire or wires; and b) the crimping function, which requires means for forcing the clip ends around the wires. The crimping function preferably forces the clip ends tightly around the wire, frictionally engaging the wire on two or more sides. The sliding function preferably holds the back and/or sides of the clip snug against the post, so that there is little or no slack in the clip around the post once the crimping action to done. As described earlier in this document, the handle or handles may also serve to actuate means for gripping, closing around, or otherwise bracing the tool against the post and/or wire.
The preferred embodiment utilizes two separate handles and assemblies for performing the two preferred functions of the tool, with the sliding handle also serving to cause the gripping action around the post. However, alternatively, the inventor envisions that the tool may be made with one handle or actuator that causes both the insertion and crimping actions in sequence. This and other modifications may be made as deemed appropriate. Optionally, a more automatic actuating means may be used, such as push-button, battery-powered or other electrically-powered mechanisms, but such options are expected to add weight, limit portability, or limit the length of time the user may be in the field or lot before electric recharging.
The currently-preferred tool structure is shown to include side wall 42, which acts as a guide bar on which the rear assemblies slides, and which extends forward along the length of the tool to provide support structure for the rear assembly and also for the front assembly, that is, the pivoting mechanism with the crimping arms. A transverse structure 48 connects wall 42 to partial wall 50 which forms the opposite side support structure for the other pivoting crimping arm. Thus, the separation between the shorter walls 44 and 50 provides for the variable opening 17 which receives the fence post.
In FIG. 9, the preferred invented clip system is shown. This clip system comprises a rigid, U-shaped or almost V-shaped clip with generally straight ends. The clips are stacked in parallel planes on top of each other and an appropriate adhesive is used to connect together part or all of the top and bottom surfaces of the adjacent clips. The adhesive or other connecting means may be selected from conventional materials that may temporarily connect the clips until the sliding means pushes or otherwise forces one clip away from the others. This connection allows simpler, untangled storage and handling of the clips, and allows the user to easily count the number of clips he is starting with and the number he has installed. Storage of the stacks of clips may be done in rows of stacks or nested rows of stacks.
With this tool and clip stack or "cartridge" system, the user may insert a stack of clips and quickly install them, in effect, moving up or down the fence post quickly to attach each horizontal wire strand, and then quickly move to the next post. With the invention, the action of fence clip installation assumes a more quick and systematic motion, saving time and preventing frustration. The tool may be made of durable metal, plastic, and other materials that can withstand wear and weather for many years of service. The moving parts may be made with conventional bearing surfaces and durable surfaces for repeated contact with the clips, wire, and post.
The preferred tool allows the user to stand in front of the fence post and to operate the tool with little or no reaching of his hands around the post, and preferably without the need for the user to apply leverage to any portion of the tool at a significant distance from the users body, thus, reducing the potential for strain or injury. Optionally, other actuating means besides those shown may be designed to increase the ergonometric benefits of the tool.
FIGS. 1-9 show an embodiment that may be used to provide the clip sliding and crimping means, the means by which the tool receives and grips the post and the wire(s), and the means by which the stack of clips is received. Although this invention has been described above with reference to these particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims. | Embodiments of a fence clip installing tool and methods of using it are described. The preferred tool uses a stack of connected fence clips which are loaded in advance for semi-automatic multiple clip installations. Upon actuation, the tool places the simple, pre-shaped clip partially around the fence post, and then bends the clip ends around the wire that runs through the tool and laterally past the fence post. Thus, the clip extends around the back and two sides of the post and surrounds and grips the wire tightly on either side of the post to hold it securely against the front side of the post. The tool quickens the process of clip installation, lessens handling of clips, and results in more uniform installation, with the two clip ends extending in parallel vertical planes around the wire on either side of the post. | 1 |
FIELD OF THE INVENTION
This invention relates to sewing machines and more particularly to an improved means for delivering buttons from a vibratory reservoir to a button sewing machine.
BACKGROUND OF THE INVENTION
Versatility in today's sewing industry is no longer a goal, instead, it is a requirement. This is especially true when considering button sewing. Because of today's constantly changing patterns, the sewing station must be versatile enough to enable a quick change over from one type of button to another. To enable this quick change over process in button sewing operations, some manufacturers have moved away from conventional hardware type button delivery means and are using spring type chutes for conveying buttons or other disk-like objects from a vibratory reservoir to the sewing station of the machine. One concern with spring type chutes is that as the buttons vibrationally gravitate toward the machine they have a tendancy to "ride up" on each other resulting in a jam-up and, ultimately, creating interruption of the machine operation. To counter this problem, manufacturers have provided close to one hundred tracks for different diameters and thicknesses of buttons. Thus, one can select the appropriately sized track for the button being sewn and hopefully avoid this jam-up problem. Each chute or track, however, also requires different mounting brackets at each of its ends. Although effective, the cost considerations of this approach has led to the present invention.
BRIEF SUMMARY OF THE PRESENT INVENTION
In view of the above and in accordance with the present invention, there is provided a unique means which greatly reduces the number of tracks or chutes required while assuring uniform planar orientation of the button during its delivery from the vibratory hopper to the sewing machine. With the present invention, an elongated generally planar resilient member is inserted inside of the track and is mounted to remain in a generally parallel relationship therewith. The spacer extends substantially the length of the track and, thus, assures a constant planar orientation of the disk-like objects as they travel along the delivery path. The insertion of the spacer varys the track spacing thus allowing one spring type track to be used for multiple purposes. A plurality of upstruck, L-shaped tabs secure the spacer to the track.
It is therefore among the principal objects of this invention to provide a button guide track assembly which lends itself to today's varied applications at considerably lower costs then heretofore known.
Another object of this invention is the provision of a button guide tube track assembly which may be readily and conveniently adapted for use with a variety of button thicknesses with a minimum of part changes.
Another feature of the present invention is its ready adaptability to existing units currently in wide use.
Still a further object of this invention is the provision of a guide attachment which readily lends itself to multiple applications at a minimal price.
Yet another advantage of this invention is the practical elimination of machine downtime resulting from jammed button guide chutes.
Another object of this invention is the provision of a guide tube assembly which can be utilized to assure proper orientation of the button during its delivery from the supply source to the machine.
These objects and features, as well as other incidental ends and advantages, will become apparent from the description now to follow of the preferred embodiment shown by way of example in the accompanying drawings in which:
FIG. 1 is a side elevational view of a sewing station incorporating the present invention;
FIG. 2 is a fragmentary plan view of the present invention;
FIG. 3 is a sectional view taken along Line 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more particularly to the drawings, wherein like reference numerals indicate like parts throughout the views, there is shown in FIG. 1, a button sewing station adapted to attach buttons or other disk-like objects to a material workpiece. A sewing machine 10, provided with reciprocal needle means 12 defining a sewing zone or area, is adapted to affect the attaching operation in a well known manner. The sewing machine may be of the type disclosed in the U.S. Pat. No. 3,960,094 granted June 1, 1976 to J. C. Hsiao and incorporated herein by reference. Associated with the sewing machine is a vibratory bowl or button reservoir 14. Such vibratory bowl may be purchased from the F.M.C. Corporation under Model EB00E. Suffice it to say, the bowl is adapted to hold and seriatimly feed buttons. As seen in FIG. 2, a button guide chute assembly 16 comprised of an open ended spring type track is positioned intermediate the discharge opening 18 of the supply reservoir and the machine for delivering buttons to the receiving station, generally designated 20, of the machine.
The essence of the present invention lies in an improvement to the button guide or chute assembly 16 which intergrally aides the operation of the attaching machine. As mentioned, the button guide tube or conveyor is preferably a spring type, resilient design. As seen in FIG. 3, the conveyor has parallel, spaced apart top section means 22 and bottom section means 24 defining a guideway 26 along which the buttons gravitationally move from the vibratory bowl to the machine receiving station. The space between the top and button section means is dimensionally greater in height than the thickness of the button received from the vibratory hopper.
To economize on the number of chutes required for efficient operation of a machine of this sorts, the present invention provides a unique means which allows one chute to be used for a plurality of button thicknesses while concurrently preventing the buttons or disk-like objects from riding on top of one another thus eliminating jam-up which, ultimately, would cause interruption of the machine operation. Such unique means include an elongated, generally planar, resilient spacer member 30 adapted for insertion inside of the track for altering the space constraints of the delivery path as a function of button thickness. More importantly, the implant or insert means serves to maintain the disk-like objects in the same planar orientation as when they are initially delivered to the spring type track from the vibratory hopper. Because the insert means extend substantially the length of the button guideway, a constant planar orientation of the gravitationally fed objects may be maintained during their delivery to the machine.
As shown in FIG. 3, the insert means may be provided with a plurality of upstruck, generally L-shaped tabs 32. The L-shaped tabs are spaced at intervals along the length of the spacer and each tab is adapted to engage a wire of the spring chute. At least two tabs at each end of the spring may have their openings in opposite directions.
In assembly, the spacer will be inserted into the guide way of the untensioned spring track assembly. In such condition, the spring track assembly is shorter than the spacer. The chute or spring track will be stretched to the length of the spacer such that the ends of the track are substantially contiguous with the ends of the spacer. Once stretched, a wire of the chute may be inserted into each of the tab openings at the ends of the spacer. The stretching of the chute will hold the spacer in a position extending generally parallel with the top and bottom section means of the chute. It is preferred that the spacer be operatively associated with the top section means of the chute. Thereafter, other spring chute wires may be inserted into the remaining tabs such that the spring pressure will keep the wires engaged in the tab openings. The spacer may be interchanged depending upon the particular button thickness being sewn. Thus, the spacer may eliminate extra chutes and mounting brackets. For each chute of a different width, covering a variety of button diameters, a spacer of a corresponding width may be provided.
Thus it is apparent that there has been provided, in accordance with the invention an Apparatus For Delivering Disk-Like Objects To An Attaching Station that fully satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. | This disclosure relates to an improvement to spring type flexible chutes provided for delivering disk-like objects from a supply source to an attaching machine. The improvement includes a resilient, elongated spacer which may be inserted into the guideway of the chute for changing the space constraints thereof to maintain a uniform planar orientation of the disk-like objects between the supply source and the machine whereby allowing one chute to be used for multiple purposes. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent Application No. 2003-36594, filed Jun. 07, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a portable computer, and more particularly, to a portable computer wherein supply of electric power for the portable computer is controlled by moving a latch member provided in a main body or display part of the portable computer.
[0004] 2. Description of the Related Art
[0005] As shown in FIGS. 1 and 2, portable computers generally include a main body 100 and a display part 200 opening/closing access to an upper surface of the main body 100 .
[0006] Within the main body are the portable computer components, such as a main board (not shown), CPU (not shown), and the like. In addition, typically, the upper surface of the main body 100 includes a key board 130 , a touch pad 120 , a main power switch 110 and the like. Along a front end portion of the upper surface, of the main body 100 , there is also typically provided a latching part 140 , to latch a latch member 230 of the display part 200 (to be described in more detail below ).
[0007] The display part 200 typically includes an LCD(Liquid Crystal Display) 210 for displaying an image, e.g., the desktop image for the portable computer's operating system. The free end of the display part 200 includes the latch member 230 , capable of being latched in and released from the latching part 140 , in a closed state of the display part 200 , thereby contacting display part 200 to the upper surface of the main body 100 . The latch member 230 typically further includes an operating knob 220 for moving the latch member 230 to/from a releasing position.
[0008] In the conventional portable computer, to supply electric power to the computer system, two operations are needed: a user must open the display part 200 , relative to the main body 100 , and then push a main power switch 110 provided on a surface of the main body 100 . However, it is more convenient, if a user can supply electric power to the computer system with only one operation.
SUMMARY OF THE INVENTION
[0009] Accordingly, it is an aspect of the present invention to provide a portable computer in which supply of electric power is controlled based on a movement of a latch member provided in a main body or the display.
[0010] Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
[0011] To accomplish the above and/or additional aspects and advantages, embodiments of the present invention provide a portable computer, including a main body, a display rotatably connected to the main body, a latching portion provided in one of the main body and the display, a latch member provided in the other one of the main body and the display, opposing the latching portion, and movable between a latching position, where the latch member is latched in the latching portion such that the display is prevented from opening, and a releasing position, where the latch member is released from the latching portion, a latch switch adjacent to the latch member, such that the latch switch contacts the latch member and generates a contact signal when the latch member is at the releasing position, and a controller supplying electric power to a system of the computer if the latch switch generates a contact signal.
[0012] To accomplish the above and/or additional aspects and advantages, embodiments of the present invention provide a method of powering a computer, with the computer having a main body rotatably connected to a display and a latch for latching the main body and the display together, including moving a latch member of the latch from a latching position to a releasing position, and initiating a powering of the computer when the latch member is at the releasing position.
[0013] To accomplish the above and/or additional aspects and advantages, embodiments of the present invention provide a method of powering a computer, with the computer having a main body rotatably connected to a display and a latch for latching the main body and the display together, including moving a latch member of the latch from a latching position to a releasing position, and initiating a shutdown of the computer when the latch member is at the releasing position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
[0015] [0015]FIG. 1 is a perspective view of a conventional portable computer;
[0016] [0016]FIG. 2 is an enlarged sectional view of a latch part and a latching hole of the conventional portable computer of FIG. 1;
[0017] [0017]FIG. 3 is an exploded perspective view of a latch part and a latching hole of a portable computer, according to an embodiment of the present invention;
[0018] [0018]FIGS. 4 through 7 are sectional views illustrating operations of a latch part and a latch power switch part, according to embodiments of the present invention;
[0019] [0019]FIG. 8. is a block diagram of a control part controlling supply of electric power for the portable computer, according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.
[0021] [0021]FIG. 3 illustrates an exploded perspective view of latch part 1 and a latch power switch 3 of a portable computer, according to an embodiment of the present invention. As illustrated in FIG. 3, the latch part 1 is provided in the middle of a free end part of a display part 200 . A latch power switch 3 is provided in the display part 200 in a position corresponding to the latch part 1 .
[0022] The latch part 1 can be oriented into a latch accommodating part 2 , formed in the middle of a free end of the display part 200 , with a latch cover 4 of the latch part 1 covering the latch accommodating part 2 . Latch member 12 , accommodated in the latching part 140 , can be externally operated, e.g., by an operation knob 11 , and moved between a latching position (the position A in FIG. 4) and a releasing position (the position B in FIG. 5). Within the latch part 1 , a spring 15 elastically pushes the latch member 12 in a direction of the latching position.
[0023] Within the latch accommodating part 2 there is a groove, of a predetermined length, along a longitudinal direction of the display part 200 . In addition, on one side of the latch accommodating part 2 there is provided a first spring connection loop 21 , to connect the latch accommodating part 2 of the display part 200 with one end of the spring 15 of the latch part 1 .
[0024] [0024]FIG. 3 further illustrates operation knob 11 , exposed to the outside of the latch cover 4 , and connected to the latch member 12 , to move the latch member 12 between the latching position (the position A in FIG. 4) and the releasing position (the position B in FIG. 4) within the latch accommodating part 2 . The latch member 12 includes a latching hook 13 , provided as a single body with the latch member 12 , to be latched in and released from the latching part 140 (illustrated in FIGS. 4-7). On one side of the latch member 12 , there is provided a second spring connecting loop 16 connected with the other end of the spring 15 , as illustrated in FIGS. 4-7. On the other side of the latch member 12 , there is a pushing protrusion 14 for contacting with the latch switch 3 , which will be described in greater detail below. The pushing protrusion 14 can protrude from the latch moving member 12 for a predetermined length. [ 0018 ] The latch cover 4 includes a guide hole 41 , of a sufficient length to guide an alternated movement of the latch member 12 and a hook through hole 42 , also of a sufficient length to permit the latching hook 13 to pass. The guide hole 41 and hook through hole 42 are long enough that the latching hook 13 can be moved between the latching position (the position A in FIG. 4), positioned on one side of the longitudinal direction of the latch cover 4 , and the releasing position (the position B in FIG. 5), positioned on the other side of the longitudinal direction of the latch cover 4 , when the display part 200 is opened and/or closed.
[0025] At a predetermined position, adjacent to the guide hole 41 a protruding part 43 is formed, with the protruding part 43 protruding in a transverse direction relative to a movement of the operation knob 11 so that a user can perceive that the latch member 12 is positioned at an intermediate position between the latching and releasing positions (the position C in FIG. 7)
[0026] As illustrated in FIG. 3, the latch switch 3 is provided at one side of the latch accommodating part 2 , corresponding to the pushing protrusion 14 of the latch moving member 12 . Here, the latch switch 3 is provided in the latch accommodating part 2 , such that the pushing protrusion 14 does not contact the latch switch 3 if the latch member 12 is positioned at the intermediate position (position C in FIG. 7) between the latching and releasing positions 7 )].
[0027] As illustrated in FIG. 1, a main power switch 110 can be provided on a surface of the main body 100 . Thus, a computer system can be turned on/off also with the main power switch 110 . Therefore, the portable computer according to an embodiment of the present invention can be considered as being provided with a plurality of power switches from which the computer system can be turned on/off.
[0028] As illustrated in FIG. 8, a control part 5 can be provided to control a power supplying part 6 to supply or cut off electric power of the computer system by receiving control signals generated from the main power switch 110 or from the latch switch 3 .
[0029] When the computer system is turned off, the control part 5 controls the power supplying part 6 to supply electric power to the computer system if a power on signal from the main power switch 110 or the latch switch 3 is transmitted to the control part 5 . When the computer system is turned on, the control part 5 controls the power supplying part 6 to cut off electric power of the computer system if a power off signal from the main power switch 110 or the latch switch 3 is transmitted to the control part 5 .
[0030] [0030]FIGS. 4, 5 and 7 illustrate the latch member 12 positioned at the latching position (position A), the releasing position (position B), and the intermediate position between the latching and releasing positions (position C), respectively.
[0031] To supply electric power to the computer system, with the display part 200 being open relative to the main body 100 , a user may press the main power switch 110 or move the latch member to the releasing position (the position B in FIG. 5) by moving the operation knob 11 , so that the pushing protrusion 14 comes into contact with the latch switch 3 . While the latch member 12 is being moved in the intermediate position between the latching and releasing positions (the position C in FIG. 7), the operating knob 11 only needs to be moved with the force with which the obstruction of the protruding part 43 is overcome. Here, the control part 5 controls the power supplying part 6 to supply electric power to the computer system by receiving one of the signals from the main power switch 110 or from the latch switch 3 .
[0032] To open the display part 200 , from a closed position, and supply electric power to the computer system, a user may move the operating knob 11 to the releasing position (the position B in FIG. 5), and open the display part 200 relative to the main body 100 . Then, the pushing protrusion 14 contacts the latch switch 3 . While the latch member is being moved through the intermediate position, between the latching and releasing positions, the operating knob 11 , similarly, only needs to be moved with the force with which the obstruction of the protruding part 43 is overcome. The control part 5 thereafter controls the power supplying part 6 to supply electric power to the computer system by receiving the signal from the latch switch 3 , the latch member 12 is then released from the latching part 140 , and the display part 200 is thereby opened, as illustrated in FIG. 6.
[0033] To open the display part 200 without supplying electric power to the computer system, a user may move the operating knob 11 to the intermediate position, between the locking and releasing positions, and open the display part 200 . In this case, the protruding part 43 provided on the latch cover 4 obstructively contacts to the operating knob 11 of the latch member 12 , thereby preventing the latch member 12 from moving. The latch member 12 is thereby released from the latching part 140 , but the pushing protrusion 14 does not contact to the latch switch 3 . Therefore, the display part 200 can be opened without supplying electric power to the computer system.
[0034] To supply electric power to the computer system without opening the display part 200 , a user may move the operating knob 11 to the releasing position (position B in FIG. 5) while closing the display part 200 , and thereafter release operating knob 11 . Here, the pushing protrusion 14 of the latch member 12 will contact the latch switch 3 and the latch member 12 moves to the latching position (position A in FIG. 4), so that electric power is supplied to the computer system, while the display part 200 continues to be closed.
[0035] To cut off electric power of the computer system, the same process used for supplying electric power, as described above, can similarly be applied.
[0036] In the above embodiment, two of the latching hooks 13 of the latch member 1 are provided. Alternatively, only one latching hook 10 may be provided in the latch member 1 .
[0037] As describe above, embodiments of the present invention provide for control of supply of electric power for the computer system by moving the latch member.
[0038] Although a few embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended | The present invention relates to a portable computer including a main body, a display rotatably connected to the main body, a latching portion provided in one of the main body and the display part, a latch member provided in the other one of the main body and the display and movable between a latching position, wherein the latch member is latched in the latching part and the display is prevented from opening, and a releasing position, where the latch member is released from the latching portion, a latch switch contacting the latch member if the latch member is at the releasing position, and a controller supplying electric power to a system of the computer if the latch switch generates a contact signal. | 4 |
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention pertains to a rabbet joint between two component parts and a method of forming a rabbet joint. More particularly, the present invention pertains to an apparatus and method for eliminating the radius commonly formed between the faces of an annular rabbet.
(2) Description of the Related Art
When joining components of an assembly, a rabbet is often useful on at least one of the components to provide a plurality of engagement surfaces between mating components of the assembly. In addition to providing structural support, rabbets also facilitate proper alignment of the components with respect to each other.
Typically, a rabbet takes the form of a right-angle groove or channel made into the edge of a component part that is adapted to receive and engage the corner of a mating component. As an example, rabbets are used to facilitate the assembly of components in dynamoelectric devices. Dynamoelectric devices are commonly comprised of, a rotor and shaft assembly, a stator encircling the rotor and shaft assembly, a cylindrical shell housing secured to and encircling the stator, and a pair of end shields secured to the ends of the housing. Because the end shields typically support bearings mounted on the rotor and shaft assembly and thereby position the rotor and shaft assembly relative to the stator, proper alignment of the end shields with respect to the housing can be critical to the operation of the dynamoelectric device. It is therefore common to provide a rabbet around the edge of the end shield to ensure that proper alignment with the housing is made.
A prior art end shield is shown in FIG. 1 . The end shield 10 has a hole 12 that allows a shaft of a dynamoelectric device to pass therethrough. An annular boss 14 extends around the hole 12 and is adapted to support a bearing mounted on the shaft. The end shield 10 also has a cylindrical rim 16 protruding from the perimeter of its main body and has a rabbet 18 formed thereon. Although end shields similar to the end shield 10 shown are common in the industry, many variations exist. For example, in FIG. 1 the end shield 10 is shown having a solid web 19 extending from the boss 14 to the rim 16 . However, it is also common to have a plurality of spokes extending radially from the boss 14 to the rim 16 with ventilation openings therebetween in place of the solid web 19 . Similarly, it is not necessary for an end shield to have a hole 12 for passage of the shaft therethrough, nor that the rim 16 extend axially from the main body. It is an improvement to the prior art annular rabbet 18 that is a focus of this invention.
The particular prior art rabbet 18 is formed on the rim 16 of the end shield 10 . The rabbet 18 is comprised of a cylindrical surface 20 and an adjacent, perpendicular annular surface 22 . The two surfaces form a right-angle shoulder around the rim 16 adapted to engage an end of a cylindrical shell housing of the dynamoelectric device. The diameter of the cylindrical surface 20 is approximately equal to that of a cylindrical interior surface of the housing nearest the housing end. Thus when the end shield 10 is assembled onto the housing, the cylindrical surface 20 engages the interior surface, thereby radially positioning and supporting the end shield 10 relative to the housing. Similarly, the annular surface 22 is designed to axially position the end shield 10 relative to the housing by engaging an annular end surface of the housing that is perpendicular to the interior surface of the housing. Once in proper alignment, the components may be further secured to each other by fasteners, adhesives, interlocking tabs or catches, or by other means for securing together components of an assembly as known to those skilled in the art.
As shown in the detailed cross-section of the prior art rabbet 18 in FIG. 2, a radius 24 is often inadvertently formed between the annular surface 22 and the cylindrical surface 20 . This radius 24 can be the result of cutting tool wear when a machining process is used to form the rabbet 18 on the end shield 10 . Additionally, the radius 24 may be the result of wear of the dies or molds used to cast or mold the end shields 10 . When precise alignment of the components within an assembly is required, any radius 24 formed between the annular surface 22 and the cylindrical surface 20 is undesirable in that, the radius 24 may prevent the annular surface 22 from engaging its mating component resulting in improper axial alignment of the components and the undesirable appearance of a gap between the end shield 10 and the shell housing.
Prior art solutions to this problem include reworking the end shield 10 by machining the rabbet 18 using sharp cutting tools to reduce the radius 24 . The extra machining process required by this solution greatly adds to the expense of production. Since the preferred method of fabrication is to mold or cast the end shields 10 , another solution has been to periodically rework or replace the molds or dies. This solution unnecessarily burdens the production process when the molds and dies are otherwise adequate. Yet another solution is to provide a chamfer or radius on the housing between the interior surface and the annular end surface of the housing that is larger than that of the radius 24 , thus providing relief in the housing for the radius 24 when the components are properly aligned. Like the other solutions, modifying the housing increases the cost of production and it is therefore desirable to find alternative solutions to the problem that can eliminate the radius 24 without adding a process step or otherwise increasing the cost of production.
The present invention overcomes the problems associated with prior art rabbet joints by utilizing a plurality of separated coplanar surfaces in place of the prior art annular surface 22 and by positioning a plurality of cylindrical surface segments perpendicular to and between the coplanar surfaces. The aggregate of the cylindrical surface segments replaces the cylindrical surface 20 of the prior art rabbet 18 . In accordance with this invention, no common edge is formed between the coplanar surfaces and adjacent cylindrical surface segments and, therefore, no radius 24 can be formed regardless of die, mold, or tool wear during the manufacturing process. This invention allows a component, such as an end shield, to be molded or cast with an annular rabbet type fitting and to align perfectly when assembled to a sharp edged mating component, regardless of minor die or mold wear.
SUMMARY OF THE INVENTION
The annular rabbet of the present invention replaces the prior art annular rabbet on an end shield. In accordance with the present invention, an end shield is formed with a plurality of cylindrical surface segments that are spaced circumferentially about a common axis by recesses in the end shield. Perpendicular and adjacent to the cylindrical surfaces are a plurality of spaced, coplanar surfaces with recesses therebetween. The coplanar surfaces are positioned circumferentially about the common axis between the cylindrical surface segments. The cylindrical surface segments and the coplanar surfaces are adapted to engage with an end of the cylindrical shell housing. The configuration of the cylindrical surface segments and the coplanar surfaces eliminates the mutual edge or corner formed between the cylindrical surface and the annular surface on prior art end shield rabbets. By eliminating such an edge on the present invention, an undesirable radius cannot be formed thereon.
In another aspect of the invention, a method of forming a rabbet joint between two component parts of an assembly comprises the steps of forming a plurality of cylindrical surface segments on a first component with the cylindrical surface segments being separated circumferentially about a common axis by recesses formed into the first component, forming a plurality of coplanar surfaces into the first component that are separated by recesses and are perpendicular to and between the cylindrical surface segments, and engaging the first component with the second component of the assembly.
While the principle advantages and features of the present invention have been described above, a more complete and thorough understanding of the invention may be attained by referring to the drawings and detailed description of the preferred embodiments, which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a prior art end shield of a dynamoelectric device having a rabbet thereon.
FIG. 2 is a partial cross-section of the prior art end shield rabbet of FIG. 1 .
FIG. 3 is a plan view of an end shield utilizing a rabbet of the preferred embodiment of the invention.
FIG. 4 is a partial isometric view of the end shield of FIG. 3 .
FIG. 5 is a partial cross-section of the end shield of FIG. 3 taken in the plane of line 5 — 5 .
FIG. 6 is a partial cross-section of the end shield of FIG. 3 taken in the plane of line 6 — 6 .
Reference characters in the written specification indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiment of the annular rabbet of the invention is used in conjunction with the end shield of a dynamoelectric device as shown in FIG. 3 . The end shield 30 , like the prior art end shield 10 , has a center hole 12 surrounded by a cylindrical boss 14 and a peripheral rim 16 . In the preferred embodiment, the rim 16 is cylindrical and has an inner surface 32 and a concentric outer surface 34 that extend axially from the main body of the end shield 30 and terminate at a perpendicular annular end surface 36 .
In the annular rabbet of the invention, as shown with greater detail in FIG. 4, a plurality of concentric cylindrical surface segments 38 are radially recessed into the rim 16 and are circumferentially spaced around the periphery of the rim 16 . The cylindrical surface segments 38 have the same radius of curvature and are circumferentially separated about their common axis by radial recesses 40 therebetween. Perpendicular to the cylindrical surface segments 38 are a plurality of arced coplanar surfaces 42 that extend radially into the rim 16 and are circumferentially spaced around the periphery of the rim 16 . The coplanar surfaces 42 are separated circumferentially about the common axis by axial recesses 44 and are positioned circumferentially between the cylindrical surface segments 38 . The cylindrical surface segments 38 of the preferred embodiment extend axially from the annular end surface 36 of the rim 16 and terminate at the recesses 44 that separate the coplanar surfaces 42 . Similarly, the coplanar surfaces extend radially inwards from the outer surface 34 of the rim 16 and terminate at the recesses 40 that separate the cylindrical surface segments 38 . The cylindrical surface segments 38 , like the prior art end shield cylindrical surface 20 , are dimensioned to engage the interior surface of a mating member such as the cylindrical shell housing, while the coplanar surfaces 42 , like the prior art annular surface 22 , are adapted to engage the annular end surface of the mating member.
The alternating positioning of the coplanar surfaces 42 circumferentially between the cylindrical surface segments 38 eliminates the possibility of the formation of a radius therebetween. The result is an unobstructed right-angle formed between the coplanar surfaces 42 and the cylindrical surface segments 38 as shown in the partial cross-sections of the preferred embodiment in FIGS. 5 and 6. Thus, although tool, die, or mold wear during production of components may result in variations of radii 46 between the cylindrical surface segments 38 and the recesses 44 and variations of radii 46 between the coplanar surfaces 42 and the recesses 40 , the radii 46 will not interfere with the engagement and desired relative positioning of the end shield 30 with the cylindrical shell housing of the dynamoelectric device.
It is important to understand that, although the preferred embodiment is shown with cylindrical surface segments 38 facing radially outward and the coplanar surfaces 42 extending radially inward from the outer surface 34 of the rim 16 , the cylindrical surface segments 38 could face radially inwards with the coplanar surfaces extending radially outwards from the inner surface 32 of the rim 16 . In such a situation, the cylindrical surface segments 38 would be adapted to engage an outer, rather than inner cylindrical surface of the mating component. Additionally, neither the inner surface 32 nor the outer surface 34 of the rim 16 need be cylindrical. The two surfaces could be formed along a straight edge of one component that meets with a straight edge of a second component. Furthermore, the cylindrical surface segments 38 and the coplanar surfaces 42 could be formed directly on the perimeter of the end shield 30 regardless of the presence of the rim 16 .
In accordance with the invention, a preferred method of forming a rabbet joint between a first component, for example an end shield, and a second component, for example a cylindrical shell housing, comprises the steps of, forming a plurality of cylindrical surface segments 38 on the first component separated circumferentially about their common axis by recesses 40 , forming a plurality of coplanar surfaces 42 separated by recesses 44 and annularly positioned perpendicular to and circumferentially between the cylindrical surface segments 38 , and engaging the first component with the second component. The steps of forming the coplanar surfaces 42 and the cylindrical surface segments 38 can be performed by molding, casting, machining, or by any method known by those skilled in the art. In the preferred embodiment the surfaces are cast. When engaging the components, the cylindrical surface segments 38 engage the cylindrical surface of the second component as the end shield 30 is moved axially onto the second component. The engagement of the cylindrical surface segments 38 with the cylindrical surface of the second components prevents radial movement of the first component relative to the second component. Final engagement occurs when the coplanar surfaces 42 engage with the second component to limit axial movement. In the preferred embodiment, the method is utilized with the first component being the end shield of a dynamoelectric device and the second component being the housing of the device.
While the present invention has been described by reference to specific embodiments, it should be understood that modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the following claims. | A rabbet joint between two components of an assembly eliminates the possibility of the formation of an undesirable radius between angled surfaces of the rabbet by segmenting the surfaces with recesses in an alternating pattern, thus forming the rabbet surfaces without sharp edges while still providing a sharp unobstructed inside-angle between the surfaces of the rabbet. | 8 |
FIELD OF THE INVENTION
[0001] The present invention relates to a camera assembly.
BACKGROUND
[0002] Unmanned Air Vehicles (UAVs) are commonly used in surveillance operations.
[0003] Typically, UAVs tend to use gimballed cameras (i.e. cameras mounted on moveable turrets) for reconnaissance.
[0004] However, only a small area of interest can be observed at any moment in time using such an approach. Furthermore, gimballed cameras tend to adversely affect the aerodynamic profile of an aircraft upon which it is mounted, e.g. by increasing drag.
SUMMARY OF THE INVENTION
[0005] In a first aspect, the present invention provides a camera assembly for mounting on a vehicle, the camera assembly comprising: a fixture; a camera; and a mirror; wherein the fixture is arranged to be rotated relative to the vehicle about an axis; the camera is mounted on the fixture such that the camera has a substantially fixed position relative to the fixture; the mirror is mounted on the fixture such that, if the fixture rotates, the mirror rotates; the mirror is rotatable relative to the fixture about a further axis, the further axis being substantially perpendicular to the axis; and the camera is arranged to detect electromagnetic radiation reflected by the mirror.
[0006] The axis and the further axis may intersect.
[0007] The fixture may comprise a drum, the camera and the mirror are mounted inside the drum, and the axis is a longitudinal axis of the drum.
[0008] The camera assembly may further comprise a processor arranged to process images generated by the camera.
[0009] The camera assembly may further comprise storage means arranged to store images generated by the camera.
[0010] The camera assembly may further comprise transmitting means arranged to transmit images generated by the camera from the camera assembly for use by an entity remote from the camera assembly.
[0011] In a further aspect, the present invention provides a vehicle comprising a camera assembly according to the above aspect.
[0012] The vehicle may be an aircraft, and the camera assembly may be mounted on the aircraft such that the axis is substantially parallel to a roll axis of the aircraft.
[0013] The vehicle may further comprise a camera array, the camera array comprising: a plurality of array cameras having substantially fixed positions relative to each other, each array camera being arranged to, for each of a plurality of time-steps within a time period, generate an image of a respective portion of terrain, wherein the portions of terrain are such that the whole of a given area of terrain has been imaged by the end of the time period; and one or more processors arranged to: select a subset of the generated images such that the area of terrain is covered by the portions of the terrain in the images in the subset; and for an image not in the subset, if an object of interest is in that image, extracting a sub-image containing the object of interest from that image.
[0014] The fixture may be rotatable relative to the camera array.
[0015] A processor may be arranged to select a particular object of interest, and the camera assembly may be arranged to be operated depending on the selected particular object of interest so as to generate using the camera of the camera assembly one or more images of the selected a particular object of interest.
[0016] In a further aspect, the present invention provides a method of generating an image using a camera assembly according to any of the above aspects, the method comprising: selecting an object of interest; rotating the fixture about the axis and/or rotating the mirror about the further axis, such that a portion of terrain that the camera is able to image comprises the selected object of interest; and using the camera, generating one or more images of the portion of terrain comprising the selected object of interest.
[0017] The step of selecting an object of interest may comprise performing a method of capturing and processing images of an area of terrain, the method of capturing and processing images of an area of terrain comprising: for each of a plurality of time-steps within a time period, using each of a plurality of cameras in a camera array, generating an image of a respective portion of terrain, wherein the cameras in the camera array have substantially fixed positions relative to each other, and the portions of terrain are such that the whole of the terrain has been imaged by the end of the time period; selecting a subset of the generated images such that the whole of the terrain is covered by the portions of the terrain in the images in the subset; and for an image not in the subset, if an object of interest is in that image, extracting a sub-image containing the object of interest from that image.
[0018] In a further aspect, the present invention provides a program or plurality of programs arranged such that when executed by a computer system or one or more processors it/they cause the computer system or the one or more processors to operate in accordance with any of the above aspects.
[0019] In a further aspect, the present invention provides a machine readable storage medium storing a program or at least one of the plurality of programs according to the above aspect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic illustration (not to scale) of an aircraft in which an example of a camera system is implemented;
[0021] FIG. 2 is a schematic illustration (not to scale) of an array of cameras;
[0022] FIG. 3 is a schematic illustration (not to scale) of an embodiment of a camera assembly;
[0023] FIG. 4 is a schematic illustration (not to scale) of a scenario in which the aircraft will be used to implement the embodiment of the camera system;
[0024] FIG. 5 is a process flow chart showing certain steps of a process by the camera system is implemented;
[0025] FIG. 6 is a schematic illustration (not to scale) of the images captured at step s 2 of the process shown in FIG. 5 ; and
[0026] FIG. 7 is a process flow chart showing certain steps of a method of providing relatively high resolution images of a particular object to the ground base.
DETAILED DESCRIPTION
[0027] FIG. 1 is a schematic illustration (not to scale) of an aircraft 2 in which an example of a camera system 3 is implemented. This example camera system 3 is useful in understanding an embodiment of a camera assembly 6 which will be described in more detail later below.
[0028] In this example, the aircraft 2 is an unmanned air vehicle (UAV).
[0029] In this example, the aircraft 2 comprises the camera system 3 .
[0030] The camera system 3 comprises an array of camera modules, hereinafter referred to as “the array 4 ”, and an assembly comprising a further camera, hereinafter referred to as “the assembly 6 ”.
[0031] An example of the array 4 is described in more detail later below with reference to FIG. 2 .
[0032] An embodiment of the assembly 6 is described in more detail later below with reference to FIG. 3 .
[0033] In this example, the array 4 is coupled to the assembly such that two-way communication is possible between the array 4 and the assembly 6 .
[0034] FIG. 2 is a schematic illustration (not to scale) of the array 4 .
[0035] In this example, the array 4 comprises four camera modules 8 .
[0036] In this example, each of the camera modules 8 comprises a camera 10 , a processor 12 , and a means for storing images which is hereinafter referred to as a “storage 13 ”.
[0037] In this example, each of the cameras 10 is coupled to the respective processor 12 and storage 13 such that images captured by a camera 10 are sent to the respective processor 12 and stored in the respective storage 13 . Each of the cameras 10 is a high pixel count, wide field of view camera. Moreover, in this example, each of the cameras 10 of the array 4 has a fixed position relative to the aircraft 2 .
[0038] In this example, the processors 12 of each of the camera modules 8 are coupled to one another such that two-way communication is possible between each of the processors 12 .
[0039] In this example, each of the cameras 10 is used to capture an image of an area of terrain that the aircraft 2 flies over, as described in more detail later below with reference to FIG. 4 . The field of view of each of the cameras 10 is indicated in FIG. 2 by dotted lines and the reference numeral 11 . Furthermore, in this example the array 4 is coupled to a navigation device (not shown in the Figures) which accurately provides aircraft location (e.g. in terms of latitude, longitude and altitude) and aircraft orientation (e.g. in terms of aircraft roll, pitch, and yaw angles). Using the aircraft's location, the aircraft's orientation, the fixed position of the cameras 10 of the array 4 relative to the aircraft 2 , and a ground elevation, a location for the image pixels that intercept the ground can be determined for any image taken, for example using a process such as geolocation. This provides a common reference (i.e. latitude, longitude and altitude) for objects are identified and distributed to other systems (as described in more details later below).
[0040] FIG. 3 is a schematic illustration (not to scale) of the assembly 6 according to an embodiment of the present invention.
[0041] In this embodiment, the assembly 6 comprises a camera (hereinafter referred to as “the assembly camera 14 ”), a processor (hereinafter referred to as “the assembly processor 15 ”) means for storing images which is hereinafter referred to as the “assembly storage 17 ”, a mirror 16 , and a drum 18 .
[0042] In this embodiment, the assembly camera 14 is a high pixel count, narrow field of view camera. The assembly camera 14 is coupled to the assembly processor 15 such that images captured by the assembly camera 14 are sent to the assembly processor 15 and assembly storage 17 .
[0043] In this embodiment, the assembly camera 14 is used to capture an image of an area of terrain that the aircraft 2 flies over, as described in more detail later below with reference to FIG. 4 . The field of view of the assembly camera 14 is indicated in FIG. 3 by dotted lines and the reference numeral 20 . Images are captured by the assembly camera 14 from light reflected from the terrain, passing through an aperture 22 in the drum 18 , and reflected by the mirror 16 to the assembly camera 14 .
[0044] In this embodiment, the assembly camera 14 , the assembly processor 15 , the assembly storage 17 and the mirror 16 are each mounted inside the drum 18 .
[0045] In this embodiment, the assembly camera 14 has a substantially fixed position relative to the drum 18 .
[0046] In this embodiment, the drum 18 is rotatable about its axis 24 . The axis 24 of the drum 18 is indicated in FIG. 3 by dotted lines. Thus, the assembly camera 14 , the assembly processor 15 , the assembly storage 17 and the mirror 16 rotate with the drum 18 . The rotation of the assembly 6 within the aircraft 2 about the axis 24 has an effect that is described in more detail later below with reference to FIG. 4 .
[0047] In this embodiment, the drum 18 is mounted in the aircraft 2 such that the drum 18 is rotatable about its axis 24 relative to the aircraft 2 . Furthermore, the drum 18 is mounted in the aircraft 2 such that the axis 24 of the drum 18 is substantially parallel to a roll axis of the aircraft 2 , (i.e. to a direction of travel of the aircraft 2 when the aircraft 2 flies in a straight line).
[0048] In this embodiment, the mirror 16 is rotatable about an axis, hereinafter referred to as the “further axis” and indicated by a dotted line and the reference numeral 26 in FIG. 3 . In this embodiment, the further axis 26 is substantially perpendicular to the axis 24 . Furthermore, the further axis 26 is substantially fixed relative to the drum 18 . Rotation of the mirror 16 about the further axis 26 provides that the mirror 16 is able to tilt back and forward (as indicated by solid arrows in FIG. 3 and indicated by the reference numeral 28 ). The tilting of the mirror 16 has an effect that is described in more detail later below with reference to FIG. 4 .
[0049] FIG. 4 is a schematic illustration (not to scale) of a scenario in which the aircraft 2 will be used to implement the camera system 3 . The method by which the camera system 3 is implemented is described in more detail later below with reference to FIGS. 5 and 7 .
[0050] In this scenario, the aircraft 2 files over an area of terrain 30 . The aircraft 2 flies in a direction of travel indicated in FIG. 4 by solid arrows and the reference numeral 31 .
[0051] In this scenario, each of the respective cameras 10 of the array 4 takes an image of a respective portion of terrain 30 . The process by which the portions of the terrain 30 are imaged using the array 4 is described in more detail later below with reference to FIG. 5 . Each of the respective portions of the terrain is indicated in FIG. 4 by the reference numeral 32 .
[0052] In this embodiment, the array 4 captures an image of a strip of the terrain. The strip of terrain is formed of four respective portions 32 . An image is captured of each of the respective portions 32 by a respective camera 10 of the array 4 . In this embodiment, the adjacent portions 32 partially overlap such that the strip of the terrain 30 imaged by the cameras 10 is continuous. In this embodiment, the strip of terrain formed by the portions is substantially perpendicular to the direction of travel 31 of the aircraft 2 .
[0053] In this scenario, the cameras 10 take images of the terrain for a pre-determined time period, T. The time period T comprises time steps t 1 , . . . , t N .
[0054] During the time period T, as the aircraft 2 flies over the terrain 30 the cameras 10 each capture an image at each time-step t i in T, i.e. discrete images are taken by each camera 10 of the terrain 30 such that a continuous image of the terrain 30 is captured over the time-period T.
[0055] The images captured by the cameras 10 of the array 4 are processed by the processors 12 of the array 4 as described in more detail later below with reference to FIG. 5 .
[0056] Furthermore, in this scenario, the assembly camera 14 (of the assembly 6 ) takes an image of a portion of the terrain. The portion of the terrain of which an image is captured by the assembly camera 14 is hereinafter referred to as the “assembly portion” and is indicated in FIG. 4 by the reference numeral 34 . As mentioned above, in this embodiment, the ground pixel footprint of the assembly camera 14 (i.e. the size of the assembly portion 34 ) is smaller than the ground pixel footprint of a portion 32 .
[0057] In this embodiment, because the assembly camera 14 is mounted inside a drum 18 that is rotatable about the roll axis of the aircraft 2 , the assembly portion 34 is moveable relative to the portions 32 . In particular, rotating the drum 18 about its axis 24 , causes the position of the assembly portion 34 to move on the surface of the terrain 30 in a direction that is substantially perpendicular to the direction of travel 31 of the aircraft 2 . Such directions are indicated by solid arrows and by reference numerals 36 in FIG. 4 .
[0058] In this embodiment, because the mirror 16 in the assembly 6 is rotatable (i.e. can be tilted) about the further axis 26 , the assembly portion 34 is moveable relative to the portions 32 . In particular, tilting the mirror 16 about the further axis 26 , causes the position of the assembly portion 34 to move on the surface of the terrain 30 in a direction that is substantially parallel to the direction of travel 31 of the aircraft 2 . Such directions are indicated by solid arrows and by reference numerals 38 in FIG. 4 .
[0059] Thus, by rotating the drum 18 about the axis 24 by a particular amount, and by tilting the mirror 16 about the further axis 26 to have a particular angle within the drum 18 , the position of the assembly portion 34 relative to the portions 32 may be changed. In this embodiment, the assembly portion 34 may overlap one or more portions 32 to any extent, or may not overlap a portion 32 .
[0060] In this embodiment, the position of the assembly portion 34 on the terrain 30 , i.e. the portion of the ground imaged by the assembly 6 , is determined as described below with reference to FIG. 7 . Also, the images captured by the assembly camera 14 are processed by the assembly processor 15 as described in more detail later below with reference to FIG. 7 .
[0061] In this scenario, identities and locations of the images taken using the array 4 and the assembly 6 are sent from the aircraft 2 to a ground station 40 . The aircraft 2 is in two-way communication with the ground station 40 . Also, on request, processed images taken using the array 4 and the assembly 6 are sent from the aircraft 2 to a ground station 40 .
[0062] FIG. 5 is a process flow chart showing certain steps of a process by which the camera system 3 is implemented.
[0063] At step s 2 , an image of each respective portion 32 of the area of terrain 30 is captured by each respective camera 10 of the array 4 . In this embodiment, images are taken by the cameras 10 at each time-step in the time-period T. In this embodiment, the cameras 10 of the array 4 take images as quickly as possible. In this embodiment, the cameras 10 each take images at a rate of 4 frames per second, i.e. the time-steps t 1 to t N are 4 s apart. However, in other embodiments, a camera may take images at a different rate.
[0064] The aircraft 2 files over the terrain 30 during the time period T. The cameras 10 have substantially fixed positions relative to the aircraft 2 . Thus, in this embodiment, at each time-step the portions 32 of the terrain 30 have different positions on the surface of the terrain 30 .
[0065] In this embodiment, a portion 32 imaged by a camera 10 at one time-step partially overlaps the portion 32 taken by the same camera at the next time-step. In particular, in this embodiment portions 32 imaged at some of the time-steps in the time period T are covered by images taken at other time-steps.
[0066] In other words, continuous coverage of the terrain 30 that the aircraft 2 flies over is provided by a sub-set of the images taken by the cameras 10 . Depending on camera optic geometry, aircraft position, altitude and orientation and the terrain the rate at which images can be taken to achieve continuous coverage varies. In this embodiment, the cameras 10 of the array 4 take images at a rate of 4 frames per second. However, in this embodiment the rate at which images can be taken to achieve continuous coverage of the terrain 30 is a different (smaller) value, for example 0.2 frames per second (i.e. one image every 5 seconds).
[0067] In this embodiment, images taken by the cameras 10 of the array 4 at the time-steps t i , t j , t k , and t l provide a continuous image of the terrain 30 that the aircraft 2 flies over in the time period T. The set of images taken at the time-steps t i , t j , t k , and t l is a sub-set of the set of images taken at the time-steps t 1 , . . . , t N .
[0068] The portions 32 of the terrain 30 that images are taken of between the time-steps t i and t j are covered by the images taken at t i and t j . Likewise, the portions 32 of the terrain 30 that images are taken of between the time-steps t j and t k are covered by the images taken at t j and t k . Likewise, the portions 32 of the terrain 30 that images are taken of between the time-steps t k and t l are covered by the images taken at t k and t l .
[0069] Thus, in this embodiment, a substantially complete image of the surface of the terrain 30 under the aircraft 2 during the time period T is captured using the cameras 10 of the array 4 . In other words, contiguous coverage of the surface of the terrain 30 under the aircraft's flight path is provided over the time period T.
[0070] At step s 4 , the sub-set of the images that provide a continuous image of the terrain 30 that the aircraft 2 flies over in the time period T are stored at the storages 13 .
[0071] In this embodiment, images taken by a camera 10 at each of the time-steps t i , t j , t k , and t l are sent to, and stored at, the respective storage 13 for that camera 10 . The images taken at time-steps other than t i , t j , t k , and t l , which may be conveniently referred to as “intermediate images”, are not stored at this stage.
[0072] FIG. 6 is a schematic illustration (not to scale) of the images stored at step s 4 . In FIG. 6 , the rows of four images taken by the four cameras 10 of the array 4 at each of the time steps t i , t j , t k , and t l are indicated. Overlaps between the images are indicated in FIG. 6 by the reference numeral 44 .
[0073] At step s 6 , all the images captured at step s 2 by a camera 10 (i.e. at each time-step) are sent to the processor 12 corresponding to that camera 10 . The images may be sent as they are captured by the camera 10 , or e.g. after a certain number of images have been captured. The images received by the processors 12 are processed to identify objects of interest in those images. In this embodiment, a conventional object identification process is implemented, for example a feature extraction, or change detection process.
[0074] In this embodiment, each object that is identified is assigned, by a processor 12 , an object ID, such that the objects can be identified at later stages.
[0075] At step s 7 , each camera module 8 transmits the identity and location of each subset of images stored in that camera module 8 , and the identity and location of all the objects of interest identified by that camera module 8 (at step s 6 above), to each of the other camera modules 8 , the assembly 6 , and the ground station 40 .
[0076] At step s 8 , from each image in which an object of interest has been identified at step s 6 , a sub-image is extracted containing the object of interest by the processor 12 corresponding to the camera 10 that captured that image.
[0077] The sub-images that include the identified objects may be extracted using any appropriate process.
[0078] At step s 10 , the sub-images extracted (at step s 8 ) from the images taken by a camera 10 are stored in sequence (i.e. in time-order) at the storage 13 corresponding to that camera 10 .
[0079] In this embodiment, the sub-images are stored in sequence. Thus, in this embodiment the stored sequences of sub-images form video of the identified objects of interest, as described in more detail below.
[0080] At step s 12 , on request, the images that were stored at step s 4 (i.e. the images taken at time-steps t i , t j , t k , or t l ), and the sub-images stored at step s 10 are transmitted from the camera module 8 at which the images/sub-images are stored to the other camera modules 8 of the array 4 . Thus, in this embodiment information about the identified objects of interests is broadcast between the processors 12 , i.e. between the camera modules 8 . Moreover, each camera module 8 tracks the positions of each identified object within the field of view of its camera 10 . In this embodiment, a conventional object tracking processes is used.
[0081] Furthermore, at step s 12 , on request from the ground base station 40 , the image footprints for the images that were stored at step s 4 (i.e. the images taken at time-steps t i , t j , t k , or t l ), and the sub-images stored at step s 10 are transmitted to the ground station 40 . The ground station 40 may request images either automatically, or in response to operator intervention, and may request images in either reduced or full resolution.
[0082] In this embodiment, once all the images/sub-images containing a particular object of interest have been downloaded by the ground station 40 , they are compiled at the ground station 40 into a low frame rate video sequence of that object of interest. In this embodiment, the frame rate of the video of a particular object is 4 frames per second. Also, in this embodiment, a duration of a video of an object depends on whether or not the object is moving relative to the terrain 30 , and, if it is moving, with its velocity relative to the aircraft's direction of flight.
[0083] Furthermore, at step s 12 , on request the images that were stored at step s 4 (i.e. the images taken at time-steps t i , t j , t k , or t l ), and the sub-images stored at step s 10 are transmitted to the assembly 6 . In this embodiment, the assembly 6 performs a process of capturing further images or video of particular objects using the received sequences of sub-images, as described below with reference to FIG. 7 .
[0084] The images stored at step s 4 and/or the sub-images stored at step s 10 may be sent to the ground station 40 and/or the assembly 6 at the same time, or at different times.
[0085] Thus, a method of implementing the camera system 3 in which an objects of interest are identified in images taken by cameras 10 on the aircraft 2 is identified, and a relatively images/video of the objects are generated and provided to other systems (e.g. the ground station 40 , which is remote from the aircraft 2 , or the assembly 6 , which is onboard the aircraft 2 ).
[0086] In this embodiment, a process by which further images and/or videos of one or more identified objects of interest are captured is performed.
[0087] FIG. 7 is a process flow chart showing certain steps of a method of capturing further images and/or video of identified objects.
[0088] In this embodiment, the steps of the process shown in FIG. 7 are performed after those steps shown in FIG. 5 , i.e. after performing step s 12 described above.
[0089] At step s 14 , the identities and locations of all identified objects of interest that were transmitted to the assembly 6 at step s 7 , as described in more detail above, are received by the assembly 6 and analysed by the assembly processor 15 .
[0090] At step s 16 , the assembly processor 15 identifies one or more particular objects of interest of which further images and/or video are to be taken.
[0091] In this embodiment, the assembly 6 (i.e. the assembly processor 15 ) decides which objects of interest to capture high ground resolution image(s) of.
[0092] In this embodiment, this decision by the assembly processor 15 is made solely by the assembly processor 15 . The further images and/or video that are to be taken using the assembly 6 could be, for example, a single still image of each object of interest or a sequence of still images (i.e. to provide video) of one or more particular objects of interest.
[0093] In this embodiment, the images/video taken by the assembly camera 14 have higher resolution and are taken for a longer duration than those of the cameras 10 of the array 4 . In this embodiment, a particular object of interest can be identified, e.g. by the assembly 6 or ground station 40 , using the object ID assigned to it at step s 6 above (if that object was identified at step s 6 ), or an object could be referenced by its location on the surface of the terrain (e.g. if the object was not identified at step s 6 above).
[0094] In other embodiments, instructions regarding which object(s) further images and/or video are to be taken of, by the assembly 6 , may be provided to the aircraft 2 from an entity remote from the aircraft 2 , e.g. the ground station 40 . For example, an operator at the ground station 40 may analyse the images and sub-images that were transmitted to the ground station 40 from the aircraft 2 at step s 12 above, and identify one or more particular objects of interest and request further images/video of those objects from the aircraft 2 .
[0095] In this embodiment, at step s 16 the assembly processor 15 decides to take a sequence of images of a single particular object of interest to produce video footage of that object of interest.
[0096] At step s 18 , the drum 18 is rotated, and the mirror 16 is tilted, such that the assembly portion 34 (i.e. the area on the surface of the terrain 30 that is imaged by the assembly camera 14 ) is moved. This is done so that the particular object of interest on the surface of the terrain 30 lies within the assembly portion 34 .
[0097] In this embodiment, rotating the drum 18 about its axis 24 moves the assembly portion 34 on the surface of the terrain 30 in a direction that is substantially perpendicular to the direction of travel 31 of the aircraft 2 (such directions are indicated by arrows and the reference numeral 36 in FIG. 4 as described above).
[0098] In this embodiment, rotating the mirror 16 about the further axis 26 moves the assembly portion 34 on the surface of the terrain 30 in a direction that is substantially parallel to the direction of travel 31 of the aircraft 2 (such directions are indicated by arrows and the reference numeral 38 in FIG. 4 as described above).
[0099] At step s 19 , once the assembly portion has been moved such that an object on the surface of the terrain 30 lies within the assembly portion 34 , images/video are taken of that object using the assembly camera 14 . In this embodiment, these images have a higher resolution than those images taken by the cameras 10 of the array 4 .
[0100] In this embodiment, a conventional object tracking process is used so that the assembly camera 14 tracks an object as it moves relative to the aircraft 2 . This advantageously tends to provide that a period of time in which the relatively high resolution images are taken of an object is maximised. This period is from a time-step at which the object first coincides with the assembly portion 34 , to a subsequent time-step at which either the object is at a position that is not within the field of view of the assembly camera 14 or the assembly 6 is requested to provide images/video of a different target.
[0101] Thus, in this way, further images and/or video can be taken of one or more objects of interest identified at step s 16 above.
[0102] At step s 20 , the images of the object from the assembly camera 14 are stored in sequence (i.e. in time-order) at the assembly storage 17 . This stored sequence of assembly camera images provides a further images/video of the particular object of interest.
[0103] At step s 22 , the images captured at step s 18 by the assembly camera 14 are sent to the assembly processor 15 . The images are then processed.
[0104] At step 23 , the assembly processor 15 processes the received images to identify an object of interest.
[0105] At step s 24 , the assembly 6 transmits the identity and location of each image captured and stored by the assembly 6 to each of the camera modules 8 , and the ground station 40 .
[0106] At step s 6 , on request the stored assembly camera images are transmitted from the assembly 6 to the camera modules 8 and/or the ground station 40 .
[0107] Thus, a method of implementing the camera system 3 in which further (relatively high resolution) images and/or videos of one or more identified objects of interest are captured, and transmitted to the ground station 40 , is provided.
[0108] An advantage provided by the above described camera array is that the images/video taken of the terrain under the aircraft using the cameras of the array tends to be continuous and covers a relatively large area of the terrain surface. This is provided by the relatively wide field of view of the cameras of the array. Also, this is provided by, at step s 4 , selecting a sub-set of images from the set of all images taken, such that the sub-set provides continuous coverage of the terrain for storage.
[0109] A further advantage provided by the above described system is that the system is modular. In particular, each of the camera modules are separate and distinct modules. Also, the assembly is a separate module to the camera modules of the array. This tends to provides that, if desired, any of the modules of the camera system can be updated, repaired, replaced, or changed independently of the other modules of the system.
[0110] Moreover, the modularity of the system tends to provide that additional camera modules can easily be incorporated into the array, or existing camera modules can be removed from the array, as required (e.g. depending on the application or any constraints on the system such as spatial constraints imposed by the aircraft). Furthermore, due to its modularity the array is scalable so that it can be implemented on a variety of platforms.
[0111] Moreover, the modularity of the system tends to provide that processing of images etc. is not performed at a central location (i.e. by a central processor). Thus, the number of camera modules that are used in an implementation of the camera system is not limited by the processing capabilities of a central processor.
[0112] A further advantage provided by the above described system and method is that of a reduction in memory/storage requirements, and also communication bandwidth requirements, compared with that of a conventional system. This reduction in memory and communication bandwidth tends to be facilitated by not storing the whole of all of the images taken by the cameras of array. In the above embodiments, only a subset of these whole images is stored, e.g. the minimum number of images that provides a continuous coverage of the terrain that the aircraft flies over is stored. In other words, in the above embodiments, the images taken between the time-steps t i , t j , t k , or t l (i.e. the so called ‘intermediate images’) are not stored, but a continuous image of the terrain is still stored. Thus, storage requirements tends to be reduced compared to conventional techniques, for example those in which all images captured are stored and/or transmitted to another system. The reduction in memory, and communication bandwidth tends to be further facilitated by only storing and/or transmitting sub-images that contain objects of interest (i.e. as opposed to the whole image that contain the object).
[0113] An advantage provided by the assembly is that the components of the assembly tend to be mounted inside a cylindrical drum. This advantageously tends to provide the assembly has a relatively aerodynamic shape compared to conventional systems (e.g. systems in which one or more cameras are mounted in a turret on an aircraft). Thus, problems caused by increased drag or air resistance, or caused by changing an aerodynamic profile of an aircraft by affixing the assembly to it, tend to be alleviated.
[0114] A further advantage provided by the above described system and method is that, by using the array of cameras (as opposed to, for example, a camera mounted on turret) is that video of more than one object of inertest can be extracted simultaneously from within the field of view of a single camera. Furthermore, the extracted video of objects of interest from all the cameras in the array may be coupled together such that a capability of ‘videoing’ multiple objects of interest at the same time tends to be advantageously provided.
[0115] Apparatus, including the processors 12 , storage 13 , the assembly processor 15 , and assembly storage 17 , for implementing the above arrangement, and performing the above described method steps, may be provided by configuring or adapting any suitable apparatus, for example one or more computers or other processing apparatus or processors, and/or providing additional modules. The apparatus may comprise a computer, a network of computers, or one or more processors, for implementing instructions and using data, including instructions and data in the form of a computer program or plurality of computer programs stored in or on a machine readable storage medium such as computer memory, a computer disk, ROM, PROM etc., or any combination of these or other storage media.
[0116] It should be noted that certain of the process steps depicted in the flowcharts of FIGS. 5 and 7 and described above may be omitted or such process steps may be performed in differing order to that presented above and shown in the Figures. Furthermore, although all the process steps have, for convenience and ease of understanding, been depicted as discrete temporally-sequential steps, nevertheless some of the process steps may in fact be performed simultaneously or at least overlapping to some extent temporally.
[0117] In the above embodiments, the camera system is implemented on an aircraft. The aircraft is a UAV. However, in other embodiments the camera system is implemented on a different entity or system. For example, in other embodiments the camera system is implemented on a different type of vehicle (e.g. a manned aircraft, or a land-based vehicle), or a building.
[0118] In the above embodiments, the positions of the camera modules are substantially fixed relative to the aircraft. However, in other embodiments the camera modules may be moveable relative to the aircraft. For example, in other embodiments the cameras of the camera modules are substantially fixed relative to one another, but are movable (e.g. by mounting on a turret) relative to the vehicle/building they are mounted on.
[0119] In the above embodiments, the camera modules are separate modules comprising separate processors. However, in other embodiments the processing of the images captured by the cameras of the array may be performed centrally, i.e. at a central processor. Such a central processor may be on-board the aircraft, or remote from the aircraft. The use of a central processor advantageously tends to reduce the weight and size of the array. However, the above described advantages provided by the modularity of the array tend to be reduced.
[0120] In the above embodiments, the array comprises four camera modules, i.e. four cameras each coupled to a separate processor. However, in other embodiments the array comprises a different number of camera modules. In other embodiments, the array comprises a different number of cameras coupled to any number of processors. The number of camera modules, cameras and/or processors may be advantageously selected depending on any spatial/weight limitations or constraints, or depending on the scenario in which the camera system is to be implemented.
[0121] In the above embodiments, the cameras of the array are relatively wide field of view, visible light sensors. However, in other embodiments one or more of the cameras of the array is a different type of camera. For example, the cameras of the array could be infrared sensors, ultraviolet sensors, or any other type of sensor or camera.
[0122] In the above embodiments, the assembly camera is a visible light camera. However, in other embodiments the assembly camera is a different type of camera. For example, the assembly camera could be an infrared sensor, ultraviolet sensor, or any other type of sensor or camera.
[0123] In the above embodiments, the components of the assembly are mounted in a cylindrical drum. Also, the functionality that the assembly portion is moveable relative to the portions of the terrain imaged by the cameras of the array is provided by the drum being rotatable about the roll axis of the aircraft, and by a mirror that reflects light being received by the assembly camera. However, in other embodiments the functionality provided by the assembly is provided by different means. For example, in other embodiments, the assembly camera is mounted in a turret that can be operated so as to point the assembly camera in a desired direction.
[0124] In the above embodiments, the camera system is implemented in the scenario described above with reference to FIG. 4 . However, in other embodiments the camera system is implemented in a different scenario.
[0125] In the above embodiments, as the aircraft flies over the terrain, the cameras of the array are arranged to capture images of a strip of the terrain at each of a number of time-steps. In the above embodiments, the strip of terrain is substantially perpendicular to the direction of travel of the aircraft. However, in other embodiments the cameras of the array are arranged differently (i.e. are in a different configuration) so as to capture images of a differently shaped area of the terrain.
[0126] In the above embodiments, images are sent from the aircraft to a single ground base. The ground base is remote from the aircraft. However, in other embodiments, images are sent from the aircraft to a different number of ground bases. Also, in other embodiments, images are sent from the aircraft to a different type of entity (e.g. an airborne platform) remote from the aircraft. Also, in other embodiments one or more of the entities that the images are sent to, and/or the requests are received from are not remote from the aircraft, e.g. a pilot of the aircraft, or other onboard system of the aircraft.
[0127] In the above embodiments, further images and/or video of one or more particular objects of interest are captured using the assembly, and provided to the ground base, if it is determined by the assembly processor that those one or more objects are of particular interest. However, in other embodiments further images and/or video of one or more particular objects of interest are captured using the assembly, and/or provided to the ground base, if a different criteria is satisfied. For example, in other embodiments high resolution images of a particular object of interest are captured using the assembly, and/or provided to the ground base if it is determined by the processor that the object is moving with relative speed that is above a predefined threshold value, or if a request for high-resolution images is received by the aircraft/assembly from the ground station, or a source other than the ground station.
[0128] In the above embodiments, a single camera assembly is used to capture relatively high ground resolution images/video of one or more particular object of interest. However, in other embodiments, a different number of such assemblies are used, e.g. to track and/or provide images/video of a plurality of objects at the same time.
[0129] In the above embodiments, the camera assembly is used in conjunction with the array, i.e. to take images/video of objects identified by the processors of the array. However, in other embodiments, the assembly is used in conjunction with, or alongside, a different apparatus. Also, in other embodiments, the assembly is implemented independently from such an apparatus. | A camera assembly is disclosed for mounting on a vehicle (e.g. an aircraft). An exemplary camera assembly can include: a fixture (e.g. a rotatable drum); a camera; and a mirror; wherein the fixture is arranged to be rotated relative to the vehicle about an axis; the camera is mounted on the fixture such that the camera has a substantially fixed position relative to the fixture; the mirror is mounted on the fixture such that, if the fixture rotates, the mirror rotates; the mirror is rotatable relative to the fixture about a further axis, the further axis being substantially perpendicular to the axis; and the camera is arranged to detect electromagnetic radiation reflected by the mirror. The axis and the further axis may intersect. | 6 |
BACKGROUND OF THE INVENTION
This invention relates generally to closures and more particularly to a security window screen having locking and alarm features to discourage break-ins.
A window screen, while not a significant barrier to forcible entry, may impede or prevent entry by stealth, particularly if it is part of an alarm system. Prior inventors have proposed providing window screens with wires which, when tampered with, open a circuit and sound an alarm.
Other inventors have developed window screens in which the screen rolls up on a reel, like a window shade, when the screen is raised. To provide such a screen with alarm wiring, however, is difficult to do satisfactorily because the involvement of moving parts has necessitated sliding electrical contacts, which are inherently unreliable in the long term.
The present invention proposes to provide a reel-type window screen unit with a number of devices for sounding an alarm, thereby to prevent stealthful entry through the screen when an associated alarm is active.
SUMMARY OF THE INVENTION
An object of the invention is to improve the security provided by a locking window screen. By "security", we mean protection against break-ins.
A further object of the invention is to eliminate the need for brushes or other sliding electrical contacts in a security screen.
These and other objects are attained by a security screen including a frame whose top member contains a screen reel carrying a length of electrically non-conductive screen material. The screen has longitudinal electrical conductors therein running lengthwise at intervals, and hidden transverse conductors interconnecting selected pairs of the lengthwise conductors to form therewith a single, continuous but non-serpentine electrical path which is interrupted if the screen is cut. A latchable drawbar is affixed along the lower edge of the screen, so that the screen can be drawn closed, against the bias of two torsion springs within the reel. One end of each spring is mechanically connected to the reel's core, and electrically connected to one end of the conductor path; its other end is attached to one of a pair of stationary stub shafts, which are electrically isolated from one another. The springs thus serve as non-sliding rotary electrical joints.
The invention additionally provides at least one magnetic sensor for detecting movement of the reel, and a separate magnetic sensor on the frame, opposite the latchable drawbar when the screen in closed, to detect raising of the drawbar.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings,
FIG. 1 is a front sectional view of a security screen embodying the invention, as seen from inside a building, taken on a plane parallel to and in front of the screen material;
FIG. 2 is a sectional view taken on the line 2--2 in FIG. 1;
FIG. 3 is a sectional view taken on the line 3--3 in FIG. 1;
FIG. 4 is a sectional view taken on the line 4--4 in FIG. 1;
FIG. 5 is a diagram of the screen conductor path; and
FIG. 6 shows an embodiment of the invention having double-wound torsion springs.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A security screen embodying the invention includes a frame 10 comprised of symmetrical extruded hollow side channels 12,14 and a hollow top member 18 which contains a reel 20 upon which a length of screen material 22 is wound. The reel has a core 23 formed from a length of non-magnetic tubing, made preferably of a metal such as aluminum tubing or austenitic stainless steel. The free end of the screen is connected to an extruded aluminum drawbar 24 by means of a bead 25 which is retained in a slot 26 in the upper edge of the drawbar.
FIG. 1 shows the drawbar lowered, against the bottom of the window frame. In this position, the lateral edges of the screen are hidden within the side channels, as can be seen in FIG. 2, so that one cannot reach around the edges of the screen, from outside, to unlatch it. Optionally, buttons or plastic beads could be applied along the edges of the screen material, to prevent the edges from being pulled out of the undercut slots 27. Preferably, however, the vertical edges of the screen are simply maintained under slightly greater tension than the rest of the screen by the tapered inserts described below.
The top member 18 is a hollow rectangular parallelipiped or box whose end panels 28 have respective annular protrusions 30 that fit within and rotatably support plastic bearings 32 fixed in opposite ends of the reel's core 23. The upper edge of the screen material is permanently secured to the core, for example by collars 34 and screws, or by an adhesive.
A pair of stub shafts 38,39 are seated within the respective annular protrusions 30, and thus are held concentrically within the reel, at either end thereof. Each stub shaft has a square or other non-circular cross-section, and the recess in which is seated has a corresponding shape, so that neither stub shaft can rotate. The inner end of each stub shaft is affixed to one end of a respective helical torsion spring 40,42. The other end of each springs is secured to one of the reel's bearings 32. The springs may have different configurations, depending on design requirements. FIG. 1 illustrates a simple pre-tensioned helical spring, surrounding a long stub shaft which extends the length of the spring: however, it may be preferred to use a double-wound spring, illustrated in FIG. 6, since the ends of such a spring are practically in the same plane, and thus only a very short stub shaft is needed. In fact, it may be possible to eliminate the stub shafts altogether. Regardless of which type of stub shaft and spring are used, it may be observed that they constitute assemblies which are narrow enough that can be used in screen units of greatly differing widths, down to a minimum of about twice the stub shaft length.
Each spring serves two functions: first, it draws the screen upward like a window shade; second, each spring serves as an electrical conductor, performing the function of a slip ring, without requiring sliding contact.
The screen material 22 is primarily non-conducting, being woven of a strong dielectric material such as PVC-coated fiberglass threads. At intervals, however, conductive wires 43 run lengthwise of the screen (top to bottom). These wires are woven into the screen material during its manufacture, or may be subsequently affixed. In either case, the conductors should not be readily distinguishable from the non-conductive strands.
To make a continuous conductor path, so that no wire can be cut without breaking the circuit, the longitudinal wires are electrically interconnected by horizontal conductors 44, arranged in a novel pattern shown in FIG. 5. The horizontal conductors are applied to the screen at positions which are hidden in use, either within the top member 18, or within the drawbar 24. It can be seen that most, or at least some, of the horizontal conductors interconnect non-adjacent vertical conductors. That is, the electrical path is not the usual serpentine. Assuming a burglar could make out the vertical conductor wires in the screen, he would, most likely, assume they were connected conventionally. If this assumption led him to short-circuit adjacent wires before cutting through the screen, the alarm would sound.
FIG. 1 shows a wire which is secured to the movable end of the spring 40 and electrically connects it to one end of the screen conductor path. The inner end of the spring is mechanically and electrically connected to the end of the metal stub shaft 38, and an alarm wire is subsequently connected to the exposed outer end of the stub shaft. The opposite spring 42 likewise provides an electrical path between the other end of the screen conductor path and the opposite stub shaft 39, which is electrically isolated from the shaft 38. In this way, reliable, non-sliding electrical continuity is maintained between the alarm wires and the screen, even though the reel rotates through many revolutions as the screen is raised or lowered.
The screen conductors described above prevent people from cutting through the screen without being detected. One could enter, nevertheless, simply by raising the drawbar, if it were unlocked, or perhaps by pushing the screen inward with the drawbar still locked, bowing the screen enough that it could be bypassed laterally. To prevent either such mode of entry, there is a magnetic reel motion detector, comprising a permanent magnet 48 affixed to the reel, and a stationary magnetically activated sensor switch 50 installed in the top member 18 opposite the path of the magnet. See FIG. 3, which shows a gap between the magnet and the sensor switch sufficient to accommodate the thickness of the screen material rolled up on the reel when the screen is raised. During installation of the screen, the position of the magnet with respect to the switch is adjusted so that the magnet is opposite the switch (holding the switch "ON") when the screen is fully lowered. Any lifting of the drawbar, or pushing in on the screen, will thus open the switch to provide an indication of tampering, if the alarm is on.
Theoretically, one could hold the top of the screen somehow, to prevent the reel from turning (and thus "fool" the reel motion sensor), while he lifted the drawbar to gain entry to the building. So, to detect lifting of the drawbar from its lowermost (illustrated) position, a second, cylindrical, permanent magnet 52 is installed within the drawbar, at its outer end, facing a magnetic switch 54. For added safety, two such detectors may be installed, one at either end of the drawbar.
The sensor switches are connected to an alarm system, by wiring shown diagrammatically. Such systems are typically low voltage, to minimize the consequences of accidental shorts. Details of the remote alarm device are not part of this invention; it is a matter of ordinary skill to select an appropriate alarm unit, and to wire it. The number of conductors required between the screen unit and the alarm unit can be reduced to two if, as we prefer, the screen conductors and all magnetic switches are connected in series.
To lock the screen down, there are a pair of stops 56, one installed within each side member 12,14 at the bottom thereof, facing the end of the drawbar. The upper inner corner of each stop is beveled, for easy latching. The drawbar itself is an extruded hollow channel member, as shown in FIG. 4. A pair of plastic inserts 60 are inserted into the channel at either end. Each channel has a rectangular hole running lengthwise, and a sliding latch 58 is mounted in each rectangular hole. The end of the latch engages below the corresponding stop when the screen is drawn closed; its outer end is downwardly beveled so that the bar is driven inward when the screen is drawn down, past the stops 56.
The inner end of the latch member is joined to a threaded rod 62 that extends toward the center of the bottom member. A spring 64 shown in FIG. 1 around the rod normally keeps the latch member extended. One releases each latch by displacing it inwardly, toward the vertical center plane of the screen, by means of a finger pull 66 which is screwed into an internally threaded slider 68 mounted on the rod. The pull is accessible from the interior of the room, through the front channel slot. The nominal distance between the knobs can be adjusted, during assembly, but spinning the sliders on the rod.
By looking closely at FIG. 1, one can see that the top channel in the drawbar, which receives the screen's bottom bead, is not as wide as the screen. The outer inch or so of the screen bead is received in a slot in the insert; this slot forms an extension of the drawbar slot, except that it is depressed downward at about 5°. During assembly, the screen bead is first inserted into the drawbar slot. Then, the inserts are pushed in, effectively shortening the screen along its edges. When the screen is placed under tension, its edges are preferentially tightened, making it difficult to withdraw the screen edge from the slot.
Since screens must often be retrofitted into nonstandard windows, it is important to facilitate custom manufacture of the invention. All the channel members mentioned are easily cut to desired lengths by shearing or sawing; the screen can be cut to width, or provided in a variety of widths; and the reel can be shortened as well.
Inasmuch as the invention is subject to modifications and variations, it is intended that the foregoing description and the accompanying drawings shall be interpreted as illustrative of only one form of the invention, whose scope is to be measured by the following claims. | A security screen includes a rectangular frame including a top member containing a screen reel comprising a rotatable core with a length of electrically non-conductive screen material affixed thereto. The screen contains parallel electrical conductors therein running lengthwise, and transverse conductors interconnect selected pairs of the lengthwise conductors to form therewith a single continuous electrical path which is interrupted if the screen is cut. A latchable drawbar is affixed along the lower edge of the screen, so that the screen can be drawn closed, against the bias provided by two torsion springs. One end of each spring is connected to the reel's core; its other end is attached to a stationary stub shaft, which serves as a terminal for connection to an alarm. The springs are electrically joined to opposite ends of the screen's conductor path, thus serving as non-sliding rotary electrical joints. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present non-provisional application claims priority under 35 USC 119 to Japanese Patent Application No. 2004-270953 filed on Sep. 17, 2004 the entire contents thereof is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hydraulic tensioner lifter which applies tension to an endless transmission belt such as a chain or belt used in the transmission mechanism of an internal combustion engine.
2. Description of Background Art
Conventionally, in an internal combustion engine, a hydraulic tensioner lifter has been used in order to apply tension to an endless transmission belt used in the transmission mechanism, such as a chain. This hydraulic tensioner lifter uses a method which pushes a plunger by means of tensioner spring and oil pressure, where as the plunger stretches, a stretched lifter gives the chain a prescribed tension to suppress oscillation of the chain and ensure stable chain drive. See, for example, JP-A No. 287092/2003 Pages 6-7 and FIG. 2.
The hydraulic tensioner lifter as described in JP-A No. 287092/2003 includes a tensioner lifter body, a hole made in the lifter body, a plunger which is slidably fitted in the hole for forming an oil chamber in the hole of the lifter body and a tensioner spring which biases the plunger in a way to push it out of the hole, where the tensioner spring is located between the bottom of the hole and a plunger adjacent to the oil chamber side end face of an orifice member and as the plunger is pushed out by this tensioner spring and oil pressure fed into the oil chamber, it applies tension to the chain of the internal combustion engine.
In the above hydraulic tensioner lifter, while the internal combustion engine is not working, the hydraulic pump also stops working and the oil in the oil circuit of the hydraulic tensioner lifter falls down by the pull of gravity, causing air to enter the oil circuit of the hydraulic tensioner lifter. Therefore, when the engine is started, it takes some time to remove the air from the oil circuit of the hydraulic tensioner lifter and fill the oil circuit with oil.
Before the oil circuit of the hydraulic tensioner lifter is filled with oil, the endless transmission belt turns with the operation of the internal combustion engine and thus a pushing force is irregularly applied to the plunger of the hydraulic tensioner lifter. Consequently, the plunger is deeply pushed inward by a large pushing force and the plunger base end touches the tensioner body. Also, at the time of start, noise may be generated during transition of the chain from a loose state to a tense state.
If the spring constant of the tensioner spring is increased in order to avoid this, the spring force of the tensioner spring would rapidly grow with an increase in the plunging amount of the plunger, which would cause an excessive force to be applied to the endless transmission belt and thus resulting in an excessive tension on the endless transmission belt.
SUMMARY AND OBJECTS OF THE INVENTION
According to an embodiment of the present invention, a hydraulic tensioner lifter includes a tensioner body having a housing hole, a plunger slidably fitted into the housing hole, a high pressure oil chamber which is surrounded by the tensioner body and the plunger which is fed with oil pressure, and a tensioner spring which biases the plunger in the high pressure oil chamber for movement. The tensioner spring consists of a plurality of springs arranged in series.
An embodiment of the present invention includes a plunger that when it is in a position pushed inwardly by a prescribed amount from its most projecting position, the length of a spring disposed on the plunger side among the plurality of springs is fixed.
An embodiment of the present invention includes a spring that is constant of a spring disposed on the tensioner body side that is the largest among the plurality of springs.
An embodiment of the present invention includes a base of the tensioner body that faces the high pressure oil chamber, an oil inflow hole which opens into the high chamber that is made in the base, a check valve for preventing a backward flow from the high pressure oil chamber that is provided in the oil inflow hole and a relief valve that is provided downstream of the high pressure oil chamber. A first oil channel and a second oil channel are arranged in parallel from the oil inflow hole to the relief valve. The first oil passage is fitted with an orifice. In the second oil channel, the path to the relief valve is blocked off when the plunger is pushed inwardly by a prescribed amount from the most projecting position.
An embodiment of the present invention includes a valve disc of the relief valve that is conical.
An embodiment of the present invention includes a tip of the conical valve disc of the relief valve that projects from the relief valve body of the relief valve toward the first oil channel and the second oil channel.
According to an embodiment of the present invention, when the plunger is extremely projecting, the total spring length of the series of springs is longer and the spring constant of the series of springs is smaller than any of the spring constants of the individual springs. Therefore, the tensioner lifter softly bears the pushing force from the endless transmission belt in response to a change in the tension of the endless transmission belt in a plunger projecting condition, so that the endless transmission belt is stably held in place. Thus, the generation of a large tension on the endless transmission belt is prevented, thereby improving the durability of the endless transmission belt.
According to an embodiment of the present invention, while the spring constant of the series of springs is small as mentioned above with the plunger almost in its most protruding position, the length of a spring disposed on the plunger side is fixed with the plunger in a position pushed inward by a prescribed amount from its most protruding position; and when the plunger is pushed inward further, the spring on the plunger side does not function as a spring and the spring constant with the plunger in that position is larger than the spring constant with the plunger in its most protruding position. Therefore, when the plunger is more deeply pushed inwardly and the base end of the plunger comes close to the tensioner body, a large spring force is generated and contact of the plunger base end with the tensioner body is avoided, thereby preventing the generation of noise.
According to an embodiment of the present invention, because, when the plunger is pushed inwardly further from its position when pushed inwardly by a prescribed amount from its most projecting position, the spring constant is much larger than the spring constant with the plunger in its most projecting position. Thus, even when the plunger is pushed inwardly with a further pushing force, contact of the plunger base end with the tensioner body is surely avoided and the possibility of noise generation is completely eliminated.
According to an embodiment of the present invention, since a check valve that opens into a high pressure oil chamber is provided to prevent a backward flow from the high pressure oil chamber, in such a situation that after the plunger projects due to an instant slack of the endless transmission belt, the endless transmission belt becomes tense again and the plunger is about to be pushed inwardly. Thus, oil pressure which is fed to the high pressure oil chamber as a result of an increase in the capacity of the high pressure oil chamber due to the plunger's projection is prevented from flowing backward from the high pressure oil chamber to the oil path on the hydraulic pump side by the check valve when the plunger is pushed inward further.
According to an embodiment of the present invention, a relief valve is provided downstream of the high pressure oil chamber and a first oil channel and a second oil channel are arranged in parallel from the oil inflow hole to the relief valve. The first oil channel is fitted with an orifice. In the second oil channel, the path to the relief valve is blocked off when the plunger is pushed inwardly by a prescribed amount from the most projecting position. Therefore, when the plunger is between the most projecting position and the position pushed inward by the prescribed amount, the oil pressure in the high pressure oil chamber flows from the first oil channel to the relief valve and also flows from the second oil channel to the relief valve. As a consequence, the plunger is pushed inwardly with a relatively small resistance.
However, when the plunger is pushed more deeply than by the prescribed amount, the second oil channel is blocked off and thus the oil pressure in the high pressure oil chamber flows only through the first oil channel into the relief valve and due to the orifice fitted in this first oil channel the flow resistance of oil pressure is large and consequently the plunger is pushed inwardly with a large resistance. Hence, when the plunger is pushed deep into the tensioner body and the plunger base end comes closer to the base end of the tensioner body an increase in the resistance against the plunger pushing force prevents collision of the plunger base end against the base end of the tensioner body and also suppresses the generation of noise.
According to an embodiment of the present invention, since the valve disc of the relief valve is conical, the conical valve disc stably opens while oil pressure passes through the valve, which prevent chattering.
According to an embodiment of the present invention, since the tip of the conical valve disc of the relief valve or the relief valve body projects towards the first oil channel and the second oil channel, the position of the valve disc in the relief valve can be visually checked easily and properly.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood 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.
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 is a sectional view of the key part of a DOHC engine in which a hydraulic tensioner lifter according to the present invention is used as a tensioner for its timing chain;
FIG. 2 is a sectional view of the hydraulic tensioner lifter according to the present invention, taken along the line II-II of FIG. 5 ;
FIG. 3 is an exploded view of the hydraulic tensioner lifter according to the present invention;
FIG. 4 is a sectional view of the hydraulic tensioner lifter according to the present invention, taken along the line IV-IV of FIG. 5 ;
FIG. 5 is a sectional view of the hydraulic tensioner lifter according to the present invention, as viewed from the direction of arrow V;
FIG. 6( a ) to 6 ( c ) are sectional views showing three different positions of the plunger of the hydraulic tensioner lifter according to the present invention, wherein FIG. 6( a ) shows a condition that the plunger is pushed the furthest inwardly, FIG. 6( b ) is a condition wherein the plunger is in the middle projecting position, and FIG. 6( c ) is a condition wherein the plunger projects the furthest;
FIG. 7 is a sectional side view of a hydraulic tensioner lifter according to another embodiment of the present invention, wherein the plunger is pushed the most inwardly;
FIG. 8 is a view showing that the plunger in the embodiment shown in FIG. 7 that is less projecting;
FIG. 9 is a view showing that the plunger in the embodiment shown in FIG. 7 that is moderately projecting;
FIG. 10 is a view showing that the plunger in the embodiment shown in FIG. 7 that is projects the most; and
FIG. 11 is a view of a hydraulic tensioner lifter according to a further embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Next a description will be given of a hydraulic tensioner lifter 0 as an embodiment of the present invention, which is shown in FIGS. 1 to 6 . This hydraulic tensioner lifter 0 is applied to a transmission mechanism 10 of a valve train of a DOHC engine 1 . This hydraulic tensioner lifter 0 is mounted on a small vehicle with the centerline X (see FIG. 1 ) of the cylinder of the hydraulic tensioner lifter 0 inclined toward the front of the body of a small vehicle such as a motorcycle (not shown).
The above internal combustion engine 1 is a single-cylinder engine or an in-line multi-cylinder engine in which a plurality of cylinders are arranged in parallel in the vehicle width direction at regular intervals where in a cylinder block 2 of the engine 1 , a crankshaft 5 is supported in a manner that it can rotate clockwise as viewed in FIG. 1 , and a cylinder head 3 and a head cover 4 are laid over the top face of the cylinder block 2 in sequence. The cylinder block 2 , cylinder head 3 and head cover 4 are joined integrally by bolts or the like (not shown).
The above cylinder is almost perpendicular to the joint face of the cylinder block 2 and cylinder head 3 and a piston slidably fitted into this cylinder is connected to the crankshaft 5 through a connecting rod (not shown), so that as the piston goes up and down, the crankshaft 5 rotates clockwise as viewed in FIG. 1 .
A pair of intake and exhaust camshafts 6 are rotatably supported in the position of the joint face of the cylinder head 3 and head cover 4 in parallel to the crankshaft 5 and a transmission mechanism 10 lies in a transmission chamber 7 hermetically sealed by the cylinder block 2 , cylinder head 3 and head cover 4 , surrounding the crankshaft 5 and camshafts 6 .
In the transmission chamber 7 , a drive sprocket 11 is integrally fitted to the crankshaft 5 and driven sprockets whose pitch diameter is twice that of the drive sprocket 11 are integrally fitted to the pair of camshafts 6 and an endless timing chain 13 is put on the drive sprocket 11 and driven sprockets 12 so that in conjunction with clockwise rotation of the crankshaft 5 , the camshafts 6 rotate at a speed which is half the speed of rotation of the crankshaft 5 .
In the transmission chamber 7 , a chain guide 14 is provided on and in touch with the tense side 13 a of the timing chain 13 (right side in FIG. 1 ) and the lower end of a tensioner slipper 15 is swingably pivoted on the loose side 13 b of the timing chain 13 along the outer face of the timing chain 13 and the hydraulic tensioner lifter 0 is located in a rear wall mounting seat 3 a of the cylinder head 3 in a way for a front end contact member 57 of the plunger 50 of the hydraulic tensioner 0 to touch the upper part of the tensioner slipper 15 . Thus, a required level of tension is applied to the loose side 13 b of the timing chain 13 by pushing the upper part of the tensioner slipper 15 with a required pushing pressure, as set forth below.
Next, details of the structure of the hydraulic tensioner lifter 0 will be described referring to FIGS. 2 to 5 .
The hydraulic tensioner lifter 0 has, in the rear wall mounting seat 3 a of the cylinder head 3 , the following components, a tensioner body 20 detachably fitted with a bolt (not shown) passing through a flange 21 as shown in FIG. 4 and a check valve body 31 of a check valve 30 fitted into a circular check valve body housing hole 22 of the tensioner body 20 with a plunger 50 slidably fitted in a plunger housing hole 26 of the tensioner body 20 . A relief valve 60 is provided on the front end contact member 57 of the plunger 50 with an air purge valve 80 housed in an air purge valve housing hole 23 of the tensioner body 20 , wherein the check valve body housing hole 22 and the air purge valve housing hole 23 are parallel to each other.
In the tensioner body 20 , there is a tensioner body oil feed path 24 , one end of which is in communication with an engine side oil feed path 17 as shown in FIG. 1 and the other end of which opens into a circular oil feed groove 34 of an inflow oil path 37 of the check valve body 31 , where there is a connecting oil feed path 25 formed perpendicularly to the check valve body housing hole 22 and air purge valve housing hole 23 , the centerline of the tensioner body 20 coincides with the centerline of the plunger housing hole 26 and there is a circular plunger housing hole 26 in a position nearer to the front end than the check valve body housing hole 22 (the base end side is left and the front end side is right in FIGS. 2 , 3 and 4 in this embodiment).
The check valve body 31 consists of a base end large-diameter part 32 fittable into the check valve body housing hole 22 of the tensioner body 20 and a front end small-diameter part which is on the same axis as the base end large-diameter part 32 and has a diameter smaller than the base end large-diameter part 32 . The circular oil feed groove 34 is formed around the base end large-diameter part 32 and two circular grooves 35 are formed with the circular oil feed groove 34 between them with ring seals 36 being fitted into the circular grooves 35 . The base end large-diameter part 32 is oil-tightly fitted into the outer end of the check valve body housing hole 22 of the tensioner body 20 through the seals 36 . The check valve body 31 has an inflow oil path 37 , oriented in the radial direction of the check valve body 31 , which opens into the circular oil feed groove 34 .
An oil feed path 38 is in communication with the inner end of the inflow oil path 37 and oriented toward the front end of the check valve body 31 along the center axis of the check valve body 31 with a valve seat 39 being positioned at the front end of the path 38 . A ball valve housing hole 40 is provided that has a diameter larger than the oil feed path 38 . An outflow oil path 41 lies nearer to the ball valve housing hole 40 than the valve seat 39 that is radially formed and opens to the outer periphery of the front end small-diameter part 33 .
In a throttle valve body 42 pressed into the ball valve housing hole 40 of the check valve body 31 , a spring housing hole 43 , an oil path 44 with a smaller diameter than the hole 43 , a throttle 45 and a conical surface 46 are arranged in the order as identified from the base end of the check valve body 31 to its front end. A valve spring 47 is inserted in the spring housing hole 43 . The oil feed path 38 , valve seat 39 , ball valve housing hole 40 , outflow oil path 41 , valve spring 47 and ball valve 48 make up the check valve 30 . When there is no oil pressure in the oil feed path 38 , the ball valve 48 , freely fitted in the ball valve housing hole 40 , is pressed against the valve seat 39 by the spring force of the valve spring 47 to close the check valve 30 .
The plunger 50 consists of a cylindrical member 51 , a front end contact member 57 fitted to the front end of a front end small-diameter inner peripheral surface 55 in a front end small-diameter part 54 of the cylindrical member 51 , and a relief valve 60 fitted into a relief valve body housing hole 58 of the front end contact member 57 . The base end large-diameter part 52 of the cylindrical member 51 is slidably fitted into the check valve body housing hole 22 of the tensioner body 20 with the front end small-diameter part 54 of the cylindrical member 51 being slidably fitted into the plunger housing hole 26 of the tensioner body 20 . An inner step end face 56 a of a step end face 56 with which a floating sleeve 71 (stated later) can engage is formed at the boundary between the base end large-diameter inner periphery 53 of the base end large-diameter part 52 and the front end small-diameter inner peripheral surface 55 of the front end small-diameter part 54 . A guide groove 54 a is formed that is oriented toward the generating line direction on the outer peripheral surface of the front end small-diameter part 54 . Since the tip of a screw 28 is inserted into the guide groove 54 a through the outer wall 27 of the plunger housing 26 of the tensioner body 20 , the plunger 50 does not rotate and can slide axially inside the check valve body housing hole 22 and plunger housing hole 26 of the tensioner body 20 .
In the front end contact member 57 , there are an oil reservoir recess 62 which opens into the front end of the relief valve body housing hole 58 (at the rightmost end in FIGS. 2 and 3 ). A discharge oil path 63 is provided that is in communication through the oil reservoir recess 62 with ambient air. A relief valve body 61 is fitted into the relief valve body housing hole 58 with a valve holding sleeve 64 being slidably fitted onto the inner peripheral surface of the relief valve body 61 . The relief valve disc 66 of the relief valve 60 is fitted to the small-diameter part 65 of the valve holding sleeve 64 with the valve spring 68 being inserted between the end face 65 a of the small-diameter part 65 of the valve holding sleeve 64 and the front end face 58 a of the relief valve body housing hole 58 . Thus, by the spring force of this valve spring 68 , the front end conical surface 67 of the relief valve disc 66 is tightly pressed against the valve seat 69 of the relief valve 60 to close the relief valve 60 .
With the front end conical surface 67 of the relief valve disc 66 being in contact with the valve seat 69 of the relief valve 60 , when the base end face 59 (leftmost end in FIGS. 2 and 3 ) of the base end large-diameter part 52 of the plunger 50 is in contact with the stepped end face 49 of the check valve body 31 of the check valve 30 (see FIG. 2 ), a valve chest 70 exists between the front end face of the throttle valve body 42 and the base end face of the relief valve body 61 . In addition, some clearance is provided between the front end conical surface 67 of the relief valve disc 66 and the conical surface opening 46 of the throttle valve body 42 .
A rigid tensioner spring 72 with a large spring constant k 1 and a soft tensioner spring 73 with a small spring constant k 2 are arranged in series, making up a combination tensioner spring The rigid tensioner spring 72 and the floating sleeve 71 are fitted to the front end small-diameter part 33 of the check valve 30 from the front end side of the base end large-diameter part 32 and are located nearer to the front end than the floating sleeve 71 . The soft tensioner spring 73 is fitted to the front end small-diameter part 33 and the front end small-diameter inner peripheral surface 55 of the plunger 50 .
A circular oil feed groove 83 is provided on the outer peripheral surface of the air purge valve body base end 81 of the air purge valve 80 with an inflow oil path 84 which opens into the circular oil feed groove 83 along the radial direction of the air purge valve body base end 81 . An oil feed path 85 is in communication with the inner end of the inflow oil path 84 and is oriented toward the front end of the air purge valve body base end 81 along the center axis of the air purge valve body base end 81 with a valve seat 86 being provided at its front end.
At the base end of the air purge valve body front end 82 of the air purge valve 80 there is a ball valve housing hole 87 having a diameter larger than the oil feed path 85 . At the front end of the ball valve housing hole 87 there is a stepped oil path 88 having a diameter smaller than the ball valve housing hole 87 . A valve spring 89 is inserted into the large-diameter portion 88 a of the stepped oil path 88 and a ball valve 90 is housed in the ball valve housing hole 87 .
With the valve spring 89 and ball valve 90 housed inside the air purge valve body front end 82 , after the air purge valve body front end 82 is inserted into the air purge valve housing hole 23 of the tensioner body 20 , the air purge valve body base end 81 is inserted into the air purge valve housing hole 23 . Thereafter, a tool with a hexagonal columnar head (not shown) is inserted into and engaged with a hexagonal hole 91 at the base end of the air purge valve body base end 81 with the male thread 92 of the air purge valve body base end 81 being screwed into the female thread 29 of the tensioner body 20 by turning the tool in one direction so that the air purge valve 80 is built into the air purge valve housing hole 23 of the tensioner body 20 .
Since the air purging structure of the air purge valve 80 is the same as that of the air purging structure as described in JP-A No. 287092/2003, a detailed description of it is omitted here.
Next, an explanation will be given of a spring reactive force against a pushing force with no oil pressure fed to the hydraulic tensioner lifter 0 .
As illustrated in FIG. 2 , for a spring system consisting of the rigid tensioner spring 72 with a large spring constant k 1 and the soft tensioner spring 73 with a smaller spring constant k 2 which are arranged in series along the direction in which a load is applied, the combination spring constant is calculated as k 1 ·k 2 /(k 1 +k 2 ) and this combination spring constant is smaller than the spring constant k 1 of the rigid tensioner spring 72 and also smaller than the spring constant k 2 of the soft tensioner spring 73 .
When the rigid tensioner spring 72 and soft tensioner spring 73 that are arranged in series constitute a combination spring, as shown in FIG. 6 c , the plunger 50 projects largely from the tensioner body 20 and the front end face 71 a of the floating sleeve 71 is off the inner step end face 56 a of the plunger 50 with the outer step end face 56 b of the front end small-diameter part 54 and base end large-diameter part 52 being in contact with the front end side stepped end face 49 b as the boundary step between the plunger housing hole 26 and the check valve body housing hole 22 . When the plunger 50 projects the most from the tensioner body 20 , the rigid tensioner spring 72 and the soft tensioner spring 73 become serially connected and the spring constant in this condition is the abovementioned small combination spring constant k 1 ·k 2 /(k 1 +k 2 ) and the plunger 50 is slightly pushed into the check valve body housing hole 22 of the tensioner body 20 .
As the plunger 50 is progressively pushed into the check valve body housing hole 22 of the tensioner body 20 , the spring reactive force increases in proportion to the amount of pushing. When the plunger 50 is deeply pushed into the check valve body housing hole 22 of the tensioner body 20 and as illustrated in FIG. 6( b ), the front end face 71 a of the floating sleeve 71 comes into contact with the inner step end face 56 a of the plunger 50 , the pushing force applied to the plunger 50 is transmitted, without the intermediation of the soft tensioner spring 73 , from the inner step end face 56 a of the plunger 50 through the floating sleeve 71 and the rigid tensioner spring 72 to the base end large-diameter part 32 of the plunger housing hole 26 . Therefore, in this case, the spring constant is equal to the spring constant k 1 of the rigid tensioner spring 72 only and the rate of increase in the reactive force against the force pushing the plunger 50 becomes higher.
As illustrated in FIG. 6( b ), when the front end face 71 a of the floating sleeve 71 is beginning to touch the inner step end face 56 a of the plunger 50 , if the force pushing the plunger 50 increases and the plunger 50 is pushed into the check valve body housing hole 22 in a way to come closer to the base end large-diameter part 32 of the tensioner body 20 , the reactive force against the force pushing the plunger 50 by the spring force of the rigid tensioner spring 72 only becomes larger.
As illustrated in FIG. 6( a ), when the base end face 59 of the plunger 50 comes into contact with the base end side stepped end face 49 a of the check valve body 31 , the plunger 50 cannot be further pushed into the check valve body housing hole 22 .
When the internal combustion engine 1 stops working and no oil pressure is fed to the hydraulic tensioner lifter 0 , if a new timing chain 13 is put on the drive sprocket 11 and driven sprockets 12 , the plunger 50 is moved inwardly by a smaller distance (ΔX) than when the inner step end face 56 a of the plunger 50 is beginning to touch the front end face 71 a of the floating sleeve 71 as illustrated in FIG. 6( b ). The tensioner body 20 , plunger 50 , rigid tensioner spring 72 and soft tensioner spring 73 are made so that the amounts of projection of the plunger 50 , X 1 , X 2 and X 3 as shown in FIGS. 6( a ), 6 ( b ) and 6 ( c ), have the relation of X 2 −X 1 <X 3 −X 2 . Here, each of distances X, X 2 , and X 3 represent the distances in an axial direction from inner end 57 a of the front end contact member 57 of plunger 50 to face 20 a of the tensioner body 20 . Face 20 a of the tensioner body 20 abuts against a rear wall mounting seat 3 a of the cylinder head 3 .
Because the embodiment as shown in FIGS. 1 to 6 is constructed as mentioned above, when a new timing chain 13 is put on the drive sprocket 11 and driven sprockets 12 , the internal combustion engine 1 stops working and no oil pressure from a hydraulic pump is fed to the hydraulic tensioner lifter 0 , due to the tensile reactive force of the timing chain 13 . Thus, the plunger 50 is pushed into the check valve body housing hole 22 of the tensioner body 20 b more deeply by ΔX than in the condition as illustrated in FIGS. 6( a ) to 6 ( c ). At this moment, the spring force of the soft tensioner spring 73 does not work and the plunger 50 is pushed or biased outwardly only by the spring force of the rigid tensioner spring 72 .
In the initial operational stage where the internal combustion engine 1 begins working and the timing chain 13 begins turning between the drive sprocket 11 and the driven sprockets 12 , oil pressure from the hydraulic pump does not reach the hydraulic tensioner lifter 0 yet and only the spring force of the rigid tensioner spring 72 with a large spring constant k 1 bears the pushing force to the hydraulic tensioner lifter 72 as the timing chain 13 turns.
If the torque transmitted to the crankshaft 5 of the internal combustion engine 1 changes irregularly due to an intermittent combustion in the engine 1 and the tension of the timing chain 13 changes and the loose side 13 b of the timing chain 13 seriously slackens for a moment, the plunger 50 projects from the tensioner body 20 further than in the condition as illustrated in FIG. 6( b ) and the inner step end face 56 a of the plunger 50 is off the front end face 71 a of the floating sleeve 71 . In this case, the plunger 50 is pushed outwardly by the spring force with combination spring constant k 1 ·k 2 /(k 1 +k 2 ) which is smaller than the spring constant k 1 of the rigid tensioner spring 72 , so that the hydraulic tensioner lifter 0 can adequately absorb a small tension change.
Furthermore, even when the timing chain 13 is used over a long time and its length becomes larger than the original length, the hydraulic tensioner lifter 0 works in the same way as mentioned above.
As the internal combustion engine 1 begins working and a given time elapses, oil pressure from the hydraulic pump (not shown) is sent through the engine side oil feed path 17 of the engine 1 , the tensioner body oil feed path 24 of the tensioner body 20 , the circular oil feed groove 34 and the inflow oil path 37 to the oil feed path 38 . The supplied oil pressure in the oil feed path 38 opens the check valve 30 . Thus, oil pressure is supplied into the ball valve housing hole 40 with some of the supplied oil pressure in the ball valve housing hole 40 being supplied to the valve chest 70 through the spring housing hole 43 , oil path 44 , throttle 45 and conical surface opening 46 (first oil channel). Thereafter, the oil pressure is supplied from the valve chest 70 to a small-diameter oil chamber 75 and at the same time the remaining supplied oil pressure in the ball valve housing hole 40 is supplied to the oil feed path 85 through the inflow oil path 41 , large-diameter oil chamber 74 , communication oil path 25 , and circular oil feed groove 83 .
More specifically, at the early stage of hydraulic pump operation, air remains in the oil pressure circuit to the hydraulic tensioner lifter 0 and in the oil pressure circuit in the hydraulic tensioner lifter 0 and the oil pressure flowing in the oil pressure circuits contains much air. The air in the supplied oil pressure in 85 is released to the atmosphere (inside the transmission chamber) through the large-diameter part 88 a and small-diameter part 88 b of the stepped oil path 88 and the air exhaust hole 23 a of the air purge valve housing hole 23 . In addition, the air contained in the oil pressure in the oil pressure circuit to the hydraulic tensioner lifter 0 and in the oil pressure circuit of the hydraulic tensioner lifter 0 is discharged into the transmission chamber 7 .
As the pressure of the oil pressure in the oil feed path 85 is increased, due to the oil pressure the ball valve 90 touches the base end edge 88 c of the large-diameter part 88 a of the stepped oil path 88 and the air exhaust from the air purge valve 80 stops. Also, during a low speed operation just after the start of the internal combustion engine 1 , the plunger 50 is slightly pushed more towards the base end large-diameter part 32 in the check valve body housing hole 22 of the tensioner body 20 than in the condition as shown in FIG. 6( b ). Thus, the front end face 71 a of the floating sleeve 71 touches the inner step end face 56 a of the plunger 50 and the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected. Consequently, oil pressure never goes around through the outflow oil path 41 , small-diameter oil chamber 75 and large-diameter oil chamber 74 (second oil channel) into the valve chest 70 .
When the pressure of the oil pressure which is supplied into the ball valve housing hole 40 and led through the spring housing hole 43 , oil path 44 , throttle 45 and conical surface opening 46 into the valve chest 70 exceeds the relief pressure of the relief valve 60 , the front end conical surface 67 of the relief valve disc 66 of the relief valve 60 gets off the valve seat 69 and the relief valve 60 opens. If the force pushing the plunger 50 is almost constant, a large quantity of oil pressure supplied to the hydraulic tensioner lifter 0 is sent from the relief valve 60 through the relief valve body housing hole 58 and oil reservoir recess 62 to the discharge oil path 63 and discharged into the transmission chamber 7 .
If no considerable tension reactive force is generated in the timing chain 13 and the amount of the projection of the plunger 50 is larger than X 2 as shown in FIG. 6( b ), the rigid tensioner spring 72 and soft tensioner spring 73 function as a serial combination spring. Thus, the combination spring constant k 1 ·k 2 /(k 1 +k 2 ) is smaller than the spring constant k 1 of the rigid tensioner spring 72 and also smaller than the spring constant k 2 of the soft tensioner spring 73 , so that the pushing force from the timing chain 13 can be borne flexibly in response to a change in the tension of the timing chain 13 .
In addition, when the force pushing the plunger 50 decreases and the front end face 71 a of the floating sleeve 71 is released from the inner step end face 56 a of the plunger 50 as shown in FIG. ( 6 ), the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are connected. In contrast to the situation when the front end face 71 a of the floating sleeve 71 is in contact with the inner step end face 56 a of the plunger 50 , the oil pressure going through the check valve 30 into the ball valve housing hole 40 is supplied not only through the spring housing hole 43 , oil path 44 , throttle 45 and conical surface opening 46 to the valve chest 70 but also through the outflow oil path 41 , large-diameter oil chamber 74 and small-diameter oil chamber 75 to the valve chest 70 , so that even if the force pushing the plunger 50 suddenly decreases, the plunger 50 immediately projects from the tensioner body 20 in response to this situation.
When the force pushing the plunger 50 increases, the plunger 50 is pushed towards the base end large-diameter part 32 in the check valve body housing hole 22 of the tensioner body 20 and the pushing force applied to the plunger 50 can be borne by the spring force increase of the rigid tensioner spring 72 corresponding to the pushing amount. In addition, the pressure rise in the valve chest 70 and small-diameter oil chamber 75 attributable to the flow resistance of the oil pressure passing through the throttle 45 . On the other hand, when the force pushing the plunger 50 decreases, the plunger 50 projects by the spring force of the rigid tensioner spring 72 and the supply of oil pressure to the valve chest 70 by the closing of the relief valve 60 produces a drop in the oil pressure in the valve chest 70 . As a consequence, the tension of the timing chain 13 can be maintained almost constant.
Furthermore, if the force pushing the plunger 50 increases unusually, this large pushing force can be borne because the front end face 71 a of the floating sleeve 71 and the inner step end face 56 a come into contact with each other. Consequently the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected, and oil pressure from the ball valve housing hole 40 flows only through the spring housing hole 43 , throttle 45 and conical surface opening 46 into the valve chest 70 with a large flow resistance and also because of the large spring force of the rigid tensioner spring 72 that has a large spring constant. Therefore, the plunger 50 is pushed very deeply and as shown in FIG. 6( a ), it is possible to prevent the base end face 59 of the base end large-diameter part 52 of the plunger 50 from colliding with the base end stepped end face 49 a of the check valve body 31 of the tensioner body 20 to thereby prevent noise which might be generated upon contact of the plunger 50 .
Since the front end conical surface 67 is formed on the relief valve disc 66 of the relief valve 60 , the change in the pressure of oil flowing between the front end conical surface 67 and the valve seat 69 is continuous and consequently chattering hardly occurs in the relief valve 70 .
In the embodiment as shown in FIGS. 1 to 6( c ), when the front end face 71 a of the floating sleeve 71 comes into contact with the inner step end face 56 a of the cylindrical member 51 , the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected by the floating sleeve 71 and the plunger 50 and the floating sleeve 71 move together in the check valve body housing hole 22 of the tensioner body 20 and the cylindrical member 51 and the floating sleeve 71 are designed so that the soft tensioner spring 73 does not bear the pushing force applied to the front end contact member 57 of the plunger 50 . However, it is also possible that the base end large-diameter inner peripheral surface 53 of the cylindrical member 51 consists of a large-diameter part 53 a , and a small-diameter part 53 b which can touch the outer peripheral surface 71 c of the floating sleeve 70 .
In the embodiment as shown in FIGS. 7 to 10 , the plunger is slightly more inward than in its most projecting state ( FIG. 10 ), and as shown in FIG. 9 , the outer peripheral surface front end edge 71 d of the floating sleeve 71 is close to the small-diameter part 53 b of the base end large-diameter inner peripheral surface 53 of the cylindrical member 51 . As the plunger 50 is further pushed inwardly and moves from its position of FIG. 9 to the position of FIG. 8 , the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected. Thus, the oil pressure in the ball valve housing hole 40 flows from the ball valve housing hole 40 into the valve chest 70 only through the spring housing hole 43 , oil path 44 , throttle 45 and conical surface opening 46 because the large-diameter oil chamber 74 and small-diameter oil chamber 75 , constituting the second oil channel, are disconnected, where the flow resistance of the oil pressure from the ball valve housing hole 40 to the valve chest 70 is high and the resistance against the force pushing the plunger 50 is larger than when the plunger 50 moves from the position of FIG. 10 to the position of FIG. 9 .
However, while the floating sleeve 71 is moving from the position of FIG. 9 to the position of FIG. 8 , the soft tensioner spring 73 shrinks as a spring bearing the pushing force of the plunger 50 ; therefore, the spring constant of the spring which works on the plunger 50 is the small spring constant of the combination spring consisting of the rigid tensioner spring 72 and the soft tensioner spring 73 . Thus, when the floating sleeve 71 moves from the position of FIG. 9 to the position of FIG. 8 , the spring force to resist the pushing force of the plunger 50 is smaller than when the floating sleeve 71 moves from the position of FIG. 8 to the position of FIG. 7 .
When the floating sleeve 71 moves from the position of FIG. 8 to the position of FIG. 7 , the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected and the spring constant of the spring which works on the plunger 50 is the spring constant k 1 of the rigid tensioner spring 72 only and larger than the spring constant of the serial combination spring, k 1 ·k 2 /(k 1 +k 2 ). Thus, the resistance against the force pushing the plunger 50 is large.
What has been described above is summarized as follows. In the condition as shown in FIGS. 10 to 9 , the spring constant is k 1 ·k 2 /(k 1 +k 2 ), namely small and also the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are connected and the flow resistance of the oil pressure is small, so that the resistance against the force pushing the plunger 50 is the smallest. In the condition as shown in FIGS. 9 to 8 , the spring constant still remains small at k 1 ·k 2 /(k 1 +k 2 ). However, since the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected by the floating sleeve 71 , the flow resistance of the oil pressure is large so the resistance against the force pushing the plunger 50 is moderate. In the condition as shown in FIGS. 8 to 7 , the spring constant is large at k 1 ; since the large-diameter oil chamber 74 and the small-diameter oil chamber 75 are disconnected by the floating sleeve 71 , the flow resistance of the oil pressure is large so the resistance against the force pushing the plunger 50 is the largest.
While the resistance against the force pushing the plunger 50 changes in two steps in the embodiment as shown in FIGS. 1 to 6( c ), the resistance against the force pushing the plunger 50 changes in three steps in the embodiment as shown in FIGS. 7 to 10 .
Another possible embodiment of the present invention is as shown in FIG. 11 . This embodiment includes an air purge valve 100 as a purging mechanism for air and oil that is not integral with the tensioner lifter 0 but is separate from it. In addition, the air purge valve 100 is mounted in the already assembled tensioner body 20 . Thus, the basic structure and functionality of the air purge valve 100 are virtually the same as in the above embodiments and not described here.
The air purge valve 100 is disposed and mounted perpendicularly to the longitudinal direction of the tensioner body 20 and this is achieved by screwing the thread of the air purge valve 100 into a screw hole b made in the side of the tensioner body 20 and fixing the valve integrally. The air purge valve 100 comprises a base 101 which is directly screwed in the side of the tensioner body 20 with a valve spring holder 105 , screwed in the base 101 , which houses a ball valve 103 pressed into the valve seat 102 of the base 101 with a spring 104 through contact and joint of its joint surface with the base 101 in a manner to allow the valve to come into contact or out of contact freely. An extension passage 106 is screwed in the valve spring holder 105 .
The structural members 101 to 106 are serially connected with each other and extend perpendicularly to the tensioner body 20 . The air purge valve 100 may be mounted on the tensioner body 20 after the structural members 101 to 106 are joined in advance or the individual structural members 101 to 106 may be mounted on the tensioner body 20 one by one.
In this embodiment, since the air purge valve 100 is a separate unit, the structure of the tensioner lifter 0 is simplified, which makes its manufacture easy. In addition, because the air purge valve 100 can be removed as a separate unit from the tensioner body 20 for repair or adjustment purposes, repair or adjustment work can be easier, which improves working efficiency and offers an advantage in terms of cost.
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 within the scope of the following claims. | To provide an adequate biasing load to an endless transmission belt by biasing forces of a plurality of springs with different biasing forces and oil pressure biasing force to permit an easy adjustment. In a structure which includes an almost cylindrical plunger, a tensioner body into which the plunger is fitted, high pressure oil chambers are formed by the tensioner body and the plunger and supplied with oil pressure. Two tensioner springs, a rigid spring and a soft spring are supported by the tensioner body and are arranged in series for biasing the plunger. The plunger in its fully stretched state is supported by the serially arranged rigid and soft tensioner springs. In a condition when the plunger is pushed back from this fully stretched state by a prescribed amount or further, the plunger is supported by the rigid tensioner spring. | 5 |
BACKGROUND OF THE INVENTION
The invention is in the field of electrical conductors. It relates particularly to conductors adapted to receive relays and fuses, and in general elements through which pass high intensity currents.
Still more particularly, the conductors according to the invention find their application in the automotive field, as power relay modules for computers. In this case, problems arise as to the heat limit of the strength of the solder of said relays on a printed circuit board forming a support, when substantial power or more is passed through the relays and hence through the solder. It is thus clear that the strength of the solder is a question of safety of the vehicle which must be ensured.
DESCRIPTION OF THE RELATED ART
Conventionally, the present solutions are grouped in several families. On the one hand, there are known soldered relays, for example in the case of fuse relay boxes, with the use of conductive ways that are made locally thicker on a circuit board, along the path of ways that must carry current of high intensity. These lead ways thus permit the circulation of greater current without giving rise to exaggerated thermal heating. The current thus passes from the current supply cable of the battery, to the fuse, then to the relay and to an outlet connector, passing each time through lead ways. All the lead ways are gathered on a printed circuit board which also serves as a mechanical support for the fuses and relays.
Similarly, there has been envisaged the use of a circuit board with two layers of copper permitting, by the same principle, accommodating a higher current intensity.
A second family of solutions uses interfitted relays (commonly called “clips”). In this case, the connector takes the form of a thick element, for example molded, comprising means for receiving electrical pins, on which the relays and fuses are received, and internal conductors, substantially dimensioned to permit the passage of high current without excessive heating. The power current flows within the support from the battery connector, toward the fuses, then toward the relays and the outlet connector.
Apart from the relay pins through which the power passes, the control pins, through which a substantially lower current passes, are connected to the control connectors or the relays by conductors of normal cross section.
In still another conventional solution, the high current passes through the thick cables of the battery toward cable terminals on which are received the fuses and pins of the power relays, which permits the use of cables of large cross section, dimensioned as a function of the current to be carried. The control pins of the relays are thus received on cable terminals soldered on a printed circuit in a conventional manner. The control electronics thus no longer need take account of high current intensity for its dimensioning. The current outlet is also by cable.
SUMMARY OF THE INVENTION
The present invention provides a new type of power relay module, which will be easier to use.
According to the invention, the power relay module comprises a thick support comprising means for receiving the pins of fuses, relays and a battery connection, internal lead ways suitable for the passage of currents of predetermined intensity, and a printed circuit board supporting the control electronics of the relays, said support facing the circuit board, and comprising at least two zones bearing on said card.
Preferably, the support also comprises terminals for receiving the control pins of the relays, these pins being connected by control leads to electrical wires soldered on the control circuit board.
According to a particular embodiment, the thick support also comprises means for electrical connection to the circuit board in at least one bearing zone.
It will be understood that this invention thus assembles in an advantageous manner the power current conduction elements, and control elements which do not require specific dimensioning. This arrangement thus promotes easy use of the power relay module. Moreover, the integration of the connection pins directly to the electronic card provides for economic production.
The description and drawing which follow permit better understanding the objects and advantages of the invention. It is clear that this description is given only by way of example, and is not limiting.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side cross sectional view of a power relay module according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As is seen in FIG. 1, which shows in a simplified manner a power relay module 1 according to the invention in use for an automobile computer, the module is comprised of a thick support 2 and a printed circuit board 3 , supporting these components and disposed facing each other.
The support 2 comprises a terminal 4 for the connection with incoming power cable 5 , for example from a battery. This inlet connection 4 is connected by a first conductive lead way 6 to terminal 7 that supports a fuse 8 . A second lead way 9 connects this fuse 8 to a power inlet terminal 10 for a relay 15 . Similarly, a power outlet terminal 11 connects, by means of a third conductive lead way 12 , this relay 15 to an outlet terminal 13 adapted to receive within it an outlet power cable 14 .
The support 2 moreover comprises connection terminals for the pins 16 for controlling the relay 15 . These terminals are connected to substantially rectilinear electrical connectors 17 (vertical in FIG. 1 ), extending outside the support 2 , so as to be able to be soldered to the surface of the circuit board 3 .
The support 2 is a block, for example, made of a rigid plastic material by overmolding on conductive metallic lead ways, by processes known to those skilled in the art.
Finally, the support comprises, in line with the lateral projection 19 , a through connector 20 , which permits connection in the upper part by a conventional means such as a female terminal, and which at its lower part projects through a bearing zone on the circuit board 3 , thereby permitting a soldering to said circuit board 3 .
The support 2 is for example made of a rigid plastic material by overmolding on conductive metallic lead ways, by processes known to those skilled in the art.
The circuit board 3 is of the conventional type, known per se, and supports, in the present non-limiting example, components 21 forming an electronic control for the power relays of an automotive computer. It will be understood that the lateral projections 18 , 19 define a space 22 above said printed circuit board 3 and below the support 2 , sufficient to receive components 21 necessary for the control electronics, taking account of possible problems of ventilation of the components.
In the embodiment that has been described, the power current passes through the connections of the support 2 provided with receiving terminals and through suitable lead ways, without passing through the control circuit board 3 . This avoids problems of overheating the solder. Moreover, the outlet takes place from the outlet terminal 13 , integrated with the connector.
It will also be noted that the control functions of the relays are carried out by the electrical connector 17 , which are soldered to the circuit board.
There has thus been provided a power relay module that is very compact, which integrates both the control electronics and the conductors for conducting power current, by separating the functions on the one hand of electrical power transfer, and, on the other hand, of control which uses very much weaker currents. The judicious combination of the overmolded support 2 and a circuit board 3 disposed facing the latter, therefore permits achieving advantages of economy and ease of use that the prior art arrangements did not permit.
Several modifications can be considered: as a first modification, the relays are fixed by reversible reception (“clipping” according to a term currently used by those skilled in the art) on a distribution (support) inserted in a plate forming a base. In a second modification, the distributor is overmolded and then fixed in the base plate. In another modification, the relays are soldered on overmolded distributors, then fixed in the base plate. Finally, in still another modification, the relays are soldered on distributors inserted in a plate forming a base.
The scope of the present invention is not limited to the details of the embodiments set forth above by way of example, but extends on the contrary to modifications within the scope of those skilled in the art. | A power relay module includes a thick support having receiving portion for the pins of fuses, relays and a battery connector, internal lead ways suitable for the passage of current of predetermined intensity, and a circuit board supporting the control electronics of the relays, the support being disposed facing the circuit board, and having at lest two zones bearing on the board. | 8 |
FIELD OF THE INVENTION
The present invention relates to anchor points, for attaching a lanyard, strap or cable, to provide fall protection for a worker.
BACKGROUND
In construction, there is a need to tether construction workers to the structure being constructed, so that if the worker falls, the fall is short rather than deadly. What are known as “anchor points” have been provided in the prior art to help serve this purpose. Anchor points attach to the structure, e.g., the floor, wall, roof, or other structural element, and typically have a ring or through-hole to which a lanyard, strap or cable can be attached. That part of the anchor point that mounts to the structure can vary considerably; however, anchor points having rings generally share the characteristic that the ring is either fixedly disposed, or if it pivots, it does so such that the plane of the ring sweeps through a range of angles (e.g., 0-180 degrees) relative to the plane defining the surface to which the anchor point is mounted.
FIG. 1 illustrates the described pivoting. An anchor point 2 comprises a ring 4 and a strap 5 which mounts the ring to a structure 8 defining a mounting surface 6 . A Cartesian coordinate system is also shown for reference. The x and y axes of the coordinate system are aligned with the mounting surface 6 . The ring defines a plane “P” that pivots about a line “A” which is aligned with the x-axis. A line “B” is chosen that both lies in the plane P and is perpendicular to the line A, and the ring can pivot such that the angle δ defined between the line B and the mounting surface 6 varies between 0 and 180 degrees. Such anchor points will be referred to herein as pivot anchor points.
The pivot anchor point allows for pivoting that tracks a worker's movements in a plane aligned with the y and z axes. However, the present inventor has recognized that there is a need for an anchor point that provides for pivoting about the z axis, to track the worker's movements in a plane aligned with the x and y axes.
SUMMARY
A swivel anchor point for fall protection is disclosed herein. The swivel anchor point includes a ring element and a housing element. The ring element defines a closed attachment aperture, for connecting thereto a caribiner or the like. The housing element is adapted to receive and retain the ring element such that the ring element can be freely rotated through a swivel angle of at least 180 degrees about a swivel axis, and freely rotated through a pivot angle of at least 90 degrees about a pivot axis that is perpendicular to the swivel axis and that substantially intersects the swivel axis. The ring element further includes two spaced apart leg members, the leg members having foot portions extending inwardly, toward the swivel axis. The foot portions in turn have respective, spaced apart relatively enlarged ends. The housing element further includes apertures corresponding to these ends, the apertures being suitably sized, closer to the swivel axis, for pivotally receiving the ends, while being of a sufficiently smaller size, farther from the swivel axis, to prevent passage of the ends therethrough. The apertures are thereby adapted to capture the ends within the housing element for securing the ring element.
Preferably, the swivel anchor point further includes a cap and baseplate, for capturing the housing element therebetween. The cap and baseplate are separable elements.
More preferably, the cap and baseplate include corresponding portions that abut one another so as to space the cap and baseplate apart by an amount greater than that required to clamp the housing element and prevent rotation thereof about the swivel axis.
Still more preferably, one of the portions of the cap and baseplate is adapted to be captured by the other so that the portions resist displacing one of the cap and baseplate relative to the other in response to forces applied perpendicular to said swivel axis.
Yet more preferably, one of the portions is adapted to be seated in the other.
It is to be understood that this summary is provided as a means of generally determining what follows in the drawings and detailed description and is not intended to limit the scope of the invention. Objects, features and advantages of the invention will be readily understood upon consideration of the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a prior art anchor point, illustrating a pivoting capability.
FIG. 2 is an isometric view of a swivel anchor point according to the present invention.
FIG. 3 is an exploded isometric view of the swivel anchor point of FIG. 2 .
FIG. 4 is an elevation view of the anchor point of FIG. 2 mounted to a structure, illustrating a pivoting capability.
FIG. 5 is a top plan view of the anchor point of Figure, illustrating a swivelling capability.
FIG. 6 is an isometric view of a first alternative embodiment of a swivel anchor point according to the invention.
FIG. 7 is an isometric view of a second alternative embodiment of a swivel anchor point according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 2 shows a preferred swivel anchor point 10 according to the invention, and FIG. 3 shows the anchor point 10 exploded. The anchor point provides for the same pivoting provided by the pivot anchor point described above in connection with FIG. 1 , as indicated in FIG. 4 , but also provides for swiveling azimuthally, about a central or swivel axis “L I ” corresponding to the aforementioned z axis, as indicated in FIG. 5 (angle φ). In these respects, it may be noted that the anchor point 10 provides the same freedom of movement that has been provided in prior art “hoist rings.” However, the anchor point 10 provides at least three important structural points of departure, in addition to having a different use.
Referring particularly to FIG. 3 , the anchor point 10 includes a “base plate” 12 , a “ring” 14 , a “swivel house” 16 , and a “cap” 18 . The parts are shown exploded along the axis L I .
The ring 14 has a ring portion 14 a defining an attachment aperture 14 a A, for receiving a caribiner or the like, and a swivel house clearance portion 14 b defining a clearance aperture 14 b A. As shown, the overall shape of the ring 14 resembles a “D” and so it may be referred to as a “D ring.”
The ring portion 14 a of the ring 14 is “closed,” meaning that over the entire 360 degrees of its circumference there are no gaps, the purpose being to prevent the caribiner or other attachment hardware from finding a passage through the ring portion so as to become unintentionally removed therefrom. The ring portion is also preferably annular over at least the radially outermost 180 degrees of its circumference (“C”) so that the caribiner slides equally well over this range which, because the anchor point 10 can swivel as well as pivot, is sufficient to allow the user to move anywhere within a given radius of the anchor point 10 .
By contrast to the ring portion 14 a , the clearance portion 14 b is “open,” meaning that there is a gap in the aperture, here referenced as “G.”
The swivel house clearance portion 14 b of the ring 14 has two spaced apart, parallel legs 14 b L, namely 14 b L, and 14 b L 2 , each leg having a corresponding inwardly turned foot portion 14 b F, namely 14 b F, and 14 b F 2 . The foot portions 14 b F have enlarged, flanged ends 14 b FE, namely, 14 b FE, and 14 b FE 2 . The flanged ends 14 b FE are spaced apart to create the gap G.
The foot portions 14 b F are cylindrical with diameters D 1 , and the flanged ends 14 b FE are cylindrical with enlarged diameters “D 2 .”
Reference is next made to the swivel house 16 , which has a cylindrical exterior face 16 a , a plane circular base plate-facing side 16 b , and an opposed, plane circular cap-facing side 16 c (not visible in FIG. 3 , but indicated in FIG. 2 ). A circular central aperture 16 d extends through the sides 16 b and 16 c centered on the axis L I , and a pair of stepped apertures 16 e , comprising apertures 16 e , and 16 e 2 , extend through the side 16 a along a perpendicular axis L 2 that intersects the axis L I . The apertures 16 e are open to the base plate-facing side 16 b , but preferably do not extend to the cap-facing side 16 c.
The apertures 16 e have a width w 1 at the face 16 a , and the width is increased, preferably step-wise, to w 2 nearer the central aperture 16 d.
The dimension w 1 is selected to receive the foot portions 14 b F, i.e., the diameter D 1 , and the dimension w 2 is selected to receive the flanged ends 14 b FE of the foot portions, i.e., the diameter D 2 .
The base plate-facing side 16 b of the swivel house 16 is essentially “capped” by abutting the side 16 b to the base plate 12 , particularly to a circular recessed portion 12 a described below, which thereby confines the flanged ends 14 b FE in a cavity defined between the increased width portions of the apertures 16 e of the swivel house and the base plate 12 . The narrower width of the radially outermost portions of the apertures 16 e provides the important advantage of retaining the flanged ends in the cavity against laterally outwardly directed forces, particularly tensile forces applied to the D ring 14 such as by, e.g., an attached lanyard, in directions perpendicular to the axis L I .
The cavity defined by the apertures 16 e and the base plate 12 is suitably large, relative to the feet 14 b F and flanged ends 14 b FE, to allow for substantially free, pivoting rotation about the axis L 2 .
Reference is next made to the base plate 12 , which as mentioned above includes a circular, recessed surface 12 a for receiving the side 16 a of the swivel house. The recessed surface 12 a provides the advantage of seating the swivel house and retaining it against laterally directed forces.
The base plate 12 further includes a circular through-hole 12 b centered on the axis L I , and has a cylindrical inside surface 12 b 1 .
The base plate still further includes a planar mounting surface 12 c . This surface is adapted to mount to the structural member to which the anchor point is attached; particularly in this embodiment the planar surface portion 6 as described above in connection with FIG. 1 .
Reference is next made to the cap 18 , which has three cylindrical, stepped diameter portions, a base plate-facing portion 18 a , a middle portion 18 b , and a swivel house-facing portion 18 c . The base plate-facing portion 18 a has an interior surface 18 a , which defines a through-hole centered on the axis L 1 that extends through the anchor point 10 for receiving a fastener “F” (see FIGS. 2 and 4 ), as well as an outer cylindrical surface of diameter D 3 sized to fit snugly into the through hole 12 b of the base plate; the middle portion 18 b has a cylindrical exterior surface 18 b , having a diameter that is sized to be slidably received within the hole 16 c through the swivel house, as well as a supporting surface 18 b 2 ; and the outermost portion 18 c has a capping surface 18 c 1 , that abuts the cap-facing surface 16 b of the swivel house, to secure the cap to the swivel house when the cap is inserted through the hole 16 c thereof, as well as a mounting surface 18 c 2 (see also FIG. 2 ).
The through-hole defined by the base plate-facing portion 18 a as described above is preferably over-sized relative to the fastener F, providing the advantage that the fastener F may be easily removed and replaced with a fastener of a different type or even size, so that the anchor point 10 can be mounted to various sizes, forms, and configurations of structural members.
The fastener is preferably tightened down on the anchor point 10 , the tightening force being resisted by the base plate 12 and cap 18 , leaving the swivel house stress free for free rotation about the axis L 1 , carrying the ring 14 (and axis L 2 ) with it. On the other hand, the cap 18 and the base plate 12 are stationary as a result of frictional forces developed between these parts, the structure, and the head of the fastener, as a result of tightening the fastener. More specifically, the head of the fastener frictionally engages the mounting surface 18 c 2 of the cap; the supporting surface 18 b 2 of the cap frictionally engages the recessed surface 12 a of the base plate, and the outer cylindrical surface of the base plate-facing portion 18 a of the cap frictionally engages the inside cylindrical surface 12 b , of the through hole of the base plate; and the mounting surface 12 c of the base plate frictionally engages the surface 6 of the structure.
To ensure that the cap bears the tightening force rather than the swivel house, the height “H 18 ” ( FIG. 3 ) of the middle portion 18 b of the cap is provided to be sufficiently greater than the height “H 16 ” of the swivel house to allow for a slight clearance remaining between these parts when the cap compresses in response to the tightening force. Accordingly, the capping surface 18 c 1 of the cap is spaced away from the cap-facing side 16 c of the swivel house 16 so that there is substantially no frictional engagement between these surfaces.
As one alternative, FIG. 6 shows a minimal embodiment 20 of an anchor point according to the invention, that includes only the swivel house 16 and ring 14 , with the base plate-facing surface 16 a of the swivel house abutting the surface 6 of the structural member. Without suitable adaptation, tightening the fastener will clamp the swivel house to the surface 6 , and thereby hinder or completely prevent rotation of the swivel house. However, the head “H” of the fastener may be spaced above the surface 6 , such as by use of a tubular washer or stand-off (not shown), to avoid this problem. Preferably, a washer 21 would be used between the head H and the cap-facing surface 16 b of the swivel house to mediate the otherwise inevitable contact between the fastener head H and the swivel house.
FIG. 7 shows another alternative anchor point 30 according to the invention, having a base plate 12 ′ and cap 18 ′ that are modified versions, respectively, of the base plate 12 and cap 18 . The base plate 12 ′ includes a stand-off portion 12 ′ a having a distal end 12 ′ b.
The cap 18 ′ is, essentially, a washer having an internal diameter D 4 and an external diameter D 5 . The annulus thus defined seats on a distal end 12 ′ b of the stand-off portion 12 ′ a of the base plate 12 ′, so that the swivel house is captured between the base plate 12 ′ and the cap 18 ′ as in the embodiment 10 . The stand-off portion 12 ′ a of the base plate 12 ′ a projects above the floor of the baseplate by an amount H 12 ′ that is greater than the height H 16 of the swivel house 16 , so that the swivel house can freely swivel about the stand-off portion 12 ′ a.
As described, the embodiment 30 does not provide for centering the cap 18 ′ relative to the stand-off portion 12 ′ a of the base plate 12 ′. By contrast, the embodiment 10 does provide for centering the cap 18 relative to the base plate 12 , by virtue of the portion 18 a of the cap fitting into the hole 12 b of the base plate. This functionality is not essential; however, it will be readily appreciated that it is desirable and can easily be provided in the embodiment 30 in like manner.
Anchor points according to the invention preferably provide at least over 90 degrees of pivot angle θ; more preferably at least over 150 degrees of pivot angle; and still more preferably at least over 175 degrees of pivot angle, with at least 180 degrees of pivot angle being optimum. As an independent consideration, anchor points according to the invention preferably provide at least up to 180 degrees of swivel angle φ; more preferably at least 350 degrees of pivot angle; and still more preferably at least 360 degrees of pivot angle, with over 360 degrees being optimum.
It should be noted that the preferred anchor point utilizes, as described and shown, circular and cylindrical surfaces and holes, to best facilitate relative rotation of the various parts as described. However, it should be understood that this is not a requirement. For example, the foot portions 14 b F of the ring will still be able to turn within the stepped apertures 16 d of the swivel house even if the foot portions are not cylindrical, and even if they are not smooth or continuously curved, e.g., they could be hexagonal.
Moreover, the preferred anchor point uses planar abutting and mutually facing surfaces as described and shown; however, where abutting surfaces provide for frictional engagement as described, and may be replaced by non-planar surfaces providing for either frictional or specific mechanical engagement due to have complementary mating features (such as pins and holes). Also, mutually facing surfaces that are spaced apart from one another need not be planar either.
Anchor points, including anchor points according to the present invention, must be capable, when mounted to a structure, of withstanding a 5,000 pound force applied to the ring in any direction, without breaking.
It is to be understood that, while a specific swivel anchor point has been shown and described as preferred, other configurations could be utilized, in addition to those already mentioned, without departing from the principles of the invention.
The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions to exclude equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow. | A swivel anchor point for fall protection. The swivel anchor point includes a ring element and a housing element. The ring element defines a closed attachment aperture. The housing element is adapted to receive and retain the ring element such that the ring element can be freely rotated through a swivel angle of at least 180 degrees about a swivel axis, and freely rotated through a pivot angle of at least 90 degrees about a pivot axis that is perpendicular to the swivel axis and that substantially intersects the swivel axis. The ring element includes two spaced apart leg members, the leg members having foot portions extending inwardly, toward the swivel axis. The foot portions have respective, spaced apart relatively enlarged ends. The housing element includes apertures corresponding to these ends, the apertures being suitably sized, closer to the swivel axis, for pivotally receiving the ends, while being of a sufficiently smaller size, farther from the swivel axis, to prevent passage of the ends therethrough. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device making it possible to control the retraction of a mobile structure normally connected to displacement control means by a transmission mechanism, particularly in the case of a failure of said displacement control means.
A preferred use of such a device is in the space field. Thus, optical systems carried on spacecraft, such as satellites and probes, may no longer be able to fulfil their mission in a satisfactory manner if an initially mobile structure e.g. used to permit a regulation or calibration of the system, is locked in a random position, particularly as a result of a failure of the motor normally controlling its displacement, or the breaking or seizing of a mechanical connecting component.
2. Discussion of the Background
WO-A-91 19 645 proposes a device for controlling the retraction of a mobile structure, in which the structure is brought into a retracted position by spiral or torsion springs, when a pyrotechnic shear is actuated for disconnecting the motor from the mobile structure, whose displacement is controlled by said motor.
In practice, such a pyrotechnic shear has large overall dimensions and a high weight. Moreover, its use produces a shock, which can damage certain components of the optical system in the vicinity thereof, or can modify their setting.
WO-A-91 19 645, as a variant, also proposes replacing the pyrotechnic shear by an electromagnetic suction grip or a thermal knife. However, once again these are large, heavy systems, while doubts exist concerning their reliability.
As illustrated by FR-A-2 648 199, it has already been proposed to carry on a spacecraft a member made from a memory material in order to control the unclamping or release of a component such as an antenna or solar panel following launch.
FR-A-2 667 842 also proposes the use on a spacecraft of memory material members for controlling the release of rotary mechanisms incorporating ball bearings following the launch of the craft.
In the two latter documents, the memory material members are used in order to ensure a release, i.e. the bringing into the operating state of a system which must be fastened during launch in order to avoid it being damaged by violent vibrations occurring during this period. However, it has never been envisaged to use such a member for controlling the retraction of a normally mobile structure.
SUMMARY OF THE INVENTION
The invention relates to an original device making it possible to control, if this proves necessary, the retraction of a mobile structure without inducing a shock and in a particularly simple and reliable manner, for smaller overall dimensions and weight levels than in comparable, existing devices.
According to the invention, this result is achieved by means of a device for controlling the retraction of a mobile structure, which is normally connected to displacement control means by a transmission mechanism, said device incorporating disconnectable connecting means included in the transmission mechanism, and elastic means permanently acting on the mobile structure in order to automatically bring the latter into a retracted position during a disconnection of the disconnectable connecting means, characterized in that it also comprises a memory material member able to act on the disconnectable connecting means in order to control the disconnection thereof, during a state change of the material, and heating means associated with said member in order to control the state change thereof on crossing a predetermined temperature threshold.
In a preferred embodiment, the transmission mechanism comprises a first part which can be actuated by displacement control means and a second part carrying the mobile structure. The disconnectable connecting means then incorporate a tie, which traverses the first part and the second part, so as to normally join them together by friction.
The tie then advantageously defines a pivoting axis of the second part with respect to the first part, the elastic means permanently exerting a pivoting torque between the first and second parts about the axis thereof.
According to the preferred embodiment of the invention, one of the first and second parts incorporates a tubular portion, which has two truncated cone-shaped, end surfaces, the other of the first and second parts having two end fittings connected to one another by the tie through the said tubular portion. Truncated cone-shaped, bearing surfaces formed on the end fittings and complimentary of the truncated cone-shaped end surfaces of the tubular portion are normally pressed against the latter surfaces by the tie.
In this case, the memory material member is a tubular member mounted on the tie within the tubular portion, so as to be able to move apart the truncated cone-shaped bearing surfaces formed on the end fittings with respect to the truncated cone-shaped end surfaces formed on the tubular portion, during the change of state of the material.
Advantageously, thermally insulating washers are interposed between the end fittings and the memory material member, so as to ensure a uniform temperature rise of said member with a minimum dispersion.
In the aforementioned embodiment, the truncated cone-shaped end surfaces and the complimentary, truncated cone-shaped bearing surfaces are not self-locking.
Preferably, the first part is supported in pivoting manner by a fixed structure about the axis defined by the tie. The displacement control means then incorporate a motor supported by the fixed structure and whereof an output shaft rotates the first part.
In the preferred embodiment of the invention, the tie has a reduced resistance region allowing its elongation under the action of the memory material member during a change of state of said material.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail hereinafter relative to a non-limitative embodiment with reference to the attached drawings, wherein is shown:
FIG. 1 which illustrates a front view in partial section showing a mechanism making it possible to control the displacement of a mobile structure such as a mirror, said mechanism incorporating a retraction control device according to the invention; and
FIG. 2 which illustrates a side view of the mechanism illustrated in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The mechanism illustrated in FIGS. 1 and 2 is intended to be carried on a spacecraft such as a satellite or probe. This mechanism is designed to control the pivoting of a mobile structure constituted by a mirror 10 (FIG. 2) about a pivoting axis XX. As is diagrammatically illustrated in broken line form in FIG. 2, after launch, this pivoting makes it possible to bring the mirror 10 onto the optical path 12 of a not shown optical system in an optionally regulated position. In this position, the mirror 10 makes it possible to perform on the optical system an operation such as a calibration or setting. When this operation is completed, the operation of the optical system requires the retraction of the mirror 10 to its position shown in continuous line form. If, for any reason, this retraction cannot be obtained, the optical system is made inoperative.
The mechanism shown in FIGS. 1 and 2 comprises an electric stepper motor 14, constituting displacement control means for the mirror 10, as well as a transmission mechanism 16 through which the electric motor 14 drives the mirror 10. The assembly is mounted on a fixed support structure 18 which is to be fixed to the structure 10 of the satellite or probe, as shown in FIG. 2.
The body of the electric motor 14 is directly mounted in the fixed support structure 18. The latter also defines the pivoting axis XX of the mirror 10, as will be shown hereinafter.
The transmission mechanism 16 comprises a pinion 22 keyed on the output shaft of the electric motor 14, together with a first part 24 and a second part 26, normally joined to one another by disconnectable connecting means 28.
The first part 24 of the transmission mechanism 16 comprises a tubular portion 30 mounted in a bore 31 traversing the fixed support structure 18 along axis XX. More specifically, the tubular portion 30 is mounted in the bore 31 by bearings 32, such as oblique contact ball bearings, so that the first part 24 can freely pivot about the axis XX with respect to the support structure 18. At one of its ends, the tubular portion 30 of the first part 24 has a plate member 34 terminated by a toothed segment 36 engaged on the pinion 22. As a result of this arrangement, rotation in one or other direction of the pinion 22, controlled by the electric motor 14, pivots the first part 24 about the axis XX.
The second part 26 of the transmission mechanism 16 comprises a mirror-carrying portion 42, as well as two parallel plates 38, which project towards the axis XX from its mirror-carrying portion. The ends of the plates 38 are normally joined to the first part 24 by disconnectable connecting means 28. In order to ensure a satisfactory operation of these disconnectable connecting means 28, the plates 38 have a certain flexibility parallel to the axis XX. This result can easily be obtained by giving them a limited thickness and by making them from an appropriate material.
The disconnectable connecting means 28 belong to a device for controlling the retraction of the mobile structure 10. When the retraction control device is operated, the disconnectable connecting means 28 disconnect the second part 26 from the first part 24. A spiral or torsion spring 40, whose ends are respectively fixed to the first part 24 and the second part 26, then automatically controls the pivoting of said second part in a counterclockwise direction considering FIG. 2, until the mirror-carrying portion 42 of the second part 26, which carries the mirror 10, bears against an abutment 44 formed for this purpose on the fixed support structure 18. Thus, the mirror 10 is automatically Brought into the retracted position illustrated in continuous line form in FIG. 2, no matter what position was initially occupied by said mirror. In this retracted position, the mirror 10 is completely displaced from the optical path 12, so that the corresponding optical system can be continuously used without damage.
A more detailed description will now be given of the retraction control device according to the invention with reference to FIG. 1.
The disconnectable connecting means 28 incorporate a tie 46 positioned along the axis XX and connecting the ends of the plates 38 on passing through the tubular portions 30 located between said ends.
More specifically, a threaded end of the tie 46 is screwed into a dismantlable end fitting 48 forming the end of one of the plates 38. The end fitting 48 is connected to said plate 38 by screws 50. The end of the other plate 38, terminated by a second end fitting 52, is traversed by the tie 46. In its portion projecting beyond the second end fitting 52, the tie 46 also has a threaded portion on which is received a nut 54. Beyond its threaded portion receiving the nut 54, the tie 46 has a manipulating head 56 making it possible to screw the tie 46 into the dismantlable end fitting 48 by means of a wrench. On their facing faces, the end fittings 48 and 52 respectively have truncated cone-shaped bearing surfaces 58, 60.
The tie 46 is fitted coaxially within the tubular portion 30 of the first part 24, so that the truncated cone-shaped bearing surfaces 58, 60 formed on the end fittings 48, 52 are normally pressed against the truncated cone-shaped end surfaces 62, 64, complimentary of the surfaces 58 and 60 and formed in said tubular portion 30.
More specifically, the truncated cone-shaped end surface 62 is formed directly on the tubular portion 30 at its end carrying the plate member 34, whereas the truncated cone-shaped end surface 64 is formed on a race 66, which slides freely on the opposite end of the tubular portion 30. This two-part arrangement makes it possible to ensure an effective fitting or keying of the races within the ball bearings 32, by means of a spacer 67 placed between these races, when a compressive force is exerted between the end fittings 48 and 52 by the tie 46.
Contrary to the truncated cone-shaped bearing surface 58, the detachable end fitting 48 supports a post 68 terminated by a disk 70. The post 68 is positioned along axis XX within the spiral or torsion spring 40. In practice, the end of said spiral or torsion spring connected to the second part 26 is fixed to the disk 70, as shown in FIG. 1.
Besides the disconnectable connecting means 28 and elastic means constituted by the spiral or torsion spring 40, the retraction control device for the mirror 10 comprises a tubular member 72 made from shape memory material and which is located between the end fittings 48 and 52 around the tie 46 and within the tubular portion 30 of the first part 24. The memory material member 72 is dimensioned in such a way that its length does not prevent the joining by friction of the parts 24 and 26 by means of the truncated cone-shaped surfaces 58 and 62 on the one hand and 60 and 64 on the other, when the nut 54 is tightened and when the mechanism is at a normal operating temperature.
However, when the temperature of the memory material member 72 rises above a predetermined temperature threshold (e.g. between 60° and 100° C.), the dimensioning is such that the elongation of said member (e.g. by approximately 1 mm) has the effect of moving the end fittings 48 and 52 sufficiently apart to eliminate the joining by friction of the parts 24 and 26. In order for the separation of said parts to take place correctly, it should be noted that the connections by friction normally ensured between the complimentary truncated cone-shaped surfaces 58, 62 on the one hand and 60, 64 on the other are not self-locking.
In order that the elongation of the memory material member 72 has the effect of spacing apart the end fittings 48, 52, FIG. 1 shows that the tie 46 has a reduced resistance region 74. The region 74 can be constituted by a zone in which the diameter of the tie 46 is sufficiently reduced to permit its elongation, when a force tending to move apart the end fittings 48 and 52 is applied by the memory material member 72.
In order to ensure the crossing by the material forming the tubular member 72 of its phase change temperature, said tubular member is surrounded by heating means 76, e.g. constituted by an electrical resistor. The electric power supply of the resistor forming the heating means 76 is from an external source using electrical conductors not shown in the drawings.
In the embodiment shown, an insulating washer 78 is placed at each end of the tubular, memory material member 72, in order to ensure a uniform temperature rise with minimum dispersion. In addition, a thickness washer 80 and a bearing spacer 82 are interposed between the end fitting 52 and the adjacent insulating washer 78. A bearing ring 84 is interposed between the end fitting 48 and the adjacent insulating washer 78.
The bearing spacer 82 and bearing ring 84 make it possible to transmit the elongation of the tubular member 72 to the end fittings 52, 48. The thickness washer 80 is machined in the required way so as to ensure the minimum clearance for satisfactory operation of the tubular, memory material member 72.
At the time of launch, the mechanism shown in the drawings is locked in the retracted position illustrated in continuous line form in FIG. 2 by a not shown clamping device associated with the abutment 44. This clamping device can be made in a random manner and does not form part of the invention.
When the satellite or probe is under operationally conditions, the clamping device is operated so as to release the mechanism. The mirror 10 can then be brought, as desired, into the requisite position with the aid of the electric motor 14, e.g. in order to carry out a calibration or setting of the optical system. To permit the use of the optical system, it is then necessary to retract the mirror 10 by again acting on the motor 14.
As a result of an incident, due e.g. to a failure of the motor 14 or its control system, it may become impossible to retract the mirror 10 with the aid of the motor 14. Under these conditions, the continuation of the mission makes it necessary to bring the mirror into the retracted position shown in continuous line form in FIG. 2 using other means.
According to the invention, this retraction can easily be controlled by heating the tubular, memory material member 72 up to the phase change temperature of said material, e.g. between 60° and 100° C. This heating is brought about by the heating means 76. When the phase change occurs, the tubular member 72 is elongated by an adequate value (e.g. approximately 1 mm) to ensure a separation of the truncated cone-shaped surfaces 58, 62 on the one hand and 60, 64 on the other by the elongation of the region 74 of the tie 46. As soon as separation has taken place, the spiral or torsion spring 40, which acts permanently between the parts 24 and 26 to exert a pivoting torque between these parts, rotates the second part 26 in counterclockwise direction considering FIG. 2. The pivoting of the second part 26 continues until the mirror-carrying portion 42 bears against the abutment 44, as described hereinbefore.
Thus, the desired result is obtained in shock-free manner and using a particularly simple, light and small retraction control device.
It should be noted that the invention is not limited to the embodiment described with reference to the drawings. Thus, even though it has an obvious interest in the space field, it can also be used in other fields. The device can also be used for controlling the retraction of a random mobile member, whereof the described mirror only constitutes an example in the particular case of an optical system. Finally, it should be noted that the displacement of the mobile member can be a random movement such as a rotation, a translation or a more complex movement. | A unit for controlling the retraction of a mobile structure such as a mirror used for calibrating an optical system on board a spacecraft, which includes a spring which permanently forces the mobile structure towards its retracted position and a memory material member, wherein a change of state of the memory material disconnects a connecting system placed in a transmission mechanism normally connecting a control motor to the mobile structure. The connecting system normally ensures the joining by friction of two parts of the transmission mechanism between which the spring acts. A heating system controls the change of state of the memory material member. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a flat knitting machine having two opposed needle beds, and a carriage traversible along the beds, and more particularly to a system for transferring loops from the needles of one of the needle beds to the needles of the other needle bed.
2. Description of the Prior Art
A loop transferring cam system of the kind comprising a transfer cam having one nose and a receiving cam having two noses of different heights on the carriage has already been described, as for instance in German Pat. No. 660,568. This loop transferring cam system permits loop transfer to be effected only when the carriage traverses in one direction, whereas for expanding the loops that are to be transferred the needles from which the loops are transferred as well as the needles which are to receive loops must be lifted. Satisfactory loop transference and simultaneous knitting action during the same carriage traverse is impossible of attainment with this prior art system of cams.
Completely symmetrical loop transferring cam systems have also been proposed which permit loops to be transferred in a leading or trailing position to the stitch cam system during carriage traverse. These loop transferring cam systems comprise transfer cams having two noses of equal height, the leading nose in either direction of carriage traverse being used for expanding the loops that are to be transferred and the trailing nose being used for actually effecting the transfer. Loop transferring cam systems of this design have the drawback that loop expansion is not satisfactory when needles fitted with loop expanders are used.
Another problem which arises in loop transfer is that previously special devices were needed for opening the latches on the loop receiving needles. The flat knitting machine described in German Pat. No. 660,568 also requires a special device for opening the latches.
A known device for opening the latch on the receiving needle is a wire hook attached to the carriage and adapted with its point to slide along the underside of the comb of the tracked needle bed and to engage the needle directly below the needle hook. The external shape of the wire hook is such that it will retract the latch and retain it in open position during the following transferring action. In order to permit the wire hook to move into the required position the needle bed comb must be considerably undercut and in consequence weakened. If the wire loop has been slightly bent by some minor bump the latches will cease to open as required and they may even be damaged.
An alernative device for opening the latches on the receiving needles consists of flat or round brushes affixed to the carriage. However, even these brushes are not entirely reliable in opening the latches because they cannot retain the open latches during loop transference since the receiving needle is not lifted higher than into tuck position and the latch in this position is still inside the comb of the bed and behind the transferring needle which is in clearing position.
Another known method of opening the latches of the receiving needles uses magnets attached to the carriage, but this is a complex and expensive arrangement. Finally, it has been proposed for instance in the published specification of German Patent Application No. 1,585,391 to open the latches by means of the opposing needles. This has the drawback that during traverse of the carriage in one direction it is impossible to knit and to transfer loops at the same time.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a loop transferring cam system of the above specified kind which permits the loops to be transferred from the needles of the front needle bed to the needles of the back needle bed or conversely or in both directions during the same carriage traverse from right to left or from left to right before or after the needles have knitted or tucked or drawn no fresh loops.
According to the invention this object is achieved by the provision of rigid loop expanders on the needles and of a cam set comprising a transfer cam having at least three consecutive noses in the direction of carriage transverse, of which at least one nose is higher than the other nose or noses. The higher nose of the transfer cam permits the loop that is to be transferred to be satisfactorily and reliably expanded, whereas the lower nose which follows in either direction of traverse moves the needles into their transferring positions proper.
Conveniently the transfer cam may have three noses of which the nose in the middle is higher or lower than the two noses on both sides. The transferring needles are lifted by the lower noses to a sufficient height for the closed latches on the receiving needles to be opened by the transferred loops themselves as they slide over the receiving needles. Consequently, no special device for opening the latches is needed.
The higher nose causes the loop that is to be transferred to be suitably expanded and the following lower nose gives it the form required for transfer in which it is capable of opening the latch on the receiving needle. The proposed loop transferring cam system according to the invention thus permits the latches of the receiving needles to be opened automatically by the loops that are being transferred.
Different heights of the noses of the transfer cam are also absolutely necessary when needles are used which are also required to knit during the same carriage traverse as that in which they are to transfer loops to empty needles.
For the purposes of loop transference the needles of the front and of the back needle beds on the flat knitting machine are so opposed that they slide closely past each other when they are lifted. For effecting expansion of the loops the needles are provided with lateral loop expanders. When these needles are lifted for the purpose of loop transfer their loops must be expanded to ensure that the receiving needles and their hooks can reliably enter the loops which are about to be transferred. Satisfactory contact between the loops and the loop supporting shoulders on the transferring needles is possible only if the actual transferring action is preceded by a loop expanding action; the design of the transfer cam according to the invention enables this to be done. The higher nose functions as a loop expanding nose, whereas the lower nose functions as the loop transferring nose.
As the latches on the receiving needles must be open during the actual loop transferring action, the transferring needles must not be raised higher in the transferring stage by the transfer cam than will permit the loops resting on their loop supporting shoulders to slide over the hooks of the receiving needles and to open the still closed latches on the receiving needles.
The transfer cams in the front and back loop transferring cam sets are preferably symmetrically disposed with reference to the longitudinal center line of the cam carriage.
Moreover, with advantage, the cam carriage fitted with the proposed loop transferring cam system is so designed that each lower nose of the transfer cam of one of transferring cam sets is following by an up-throw cam for the receiving needles of the opposite cam set, the action ranges of the lower nose and of the up-throw cam of the receiving set at least partly overlapping.
The height of the higher or expanding nose, is determined by the needle gauge of the knitting machine.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will now be more particularly described with reference to the accompanying drawings in which:
FIG. 1 is a partial cross-section of the front and back needle beds in a flat knitting machine;
FIGS. 2 to 6 are, respectively, partial cross-sections similar to FIG. 1 but showing the needles in different positions during the transfer of loops by the proposed loop transferring cam system;
FIG. 7 is a diagrammatic plan view of a front and back loop transferring cam set; and
FIG. 8 is a schematic plan view of a different embodiment of a front loop transferring cam set.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 to 6 are partial cross-sectional views of a flat knitting machine at consecutive stages in the operation of transferring a loop of knitted fabric from a needle in one of two opposed needle beds to a needle in the other needle bed.
The knitting machine shown comprises a front needle bed 1 having needles 3 and a back needle bed 2 having needles 5. A carriage, not shown, in FIGS. 1 to 6, is traversible along the needle beds and includes stitch cams for controlling the operation of the needles 3 and 5 to produce a knitted fabric 4. The carriage also includes loop transferring cam sets 12 and 13 as shwon in FIGS. 7 or 8 which are operative to cause the transfer of a loop 9 from a needle bed 1 to a needle 5 in the back needle bed 2.
In FIG. 1 the transferring needle 3 in the front needle bed 1 carries the knitted fabric 4 and the needle is in its rest or non-knitting position. The hook of the needle 3 is open. In other words, the latch hangs down and is received into the stem of the needle. The receiving needle 5 in the back needle bed 2 is likewise in non-knitting position but it holds no fabric. The needle 5 has a latch 6 which rests on the point of the needle hook 7 so that the hook is closed.
FIG. 2 shows the next stage in the transfer of a loop from needle 3 in the front needle bed 1 to 5 in the back needle bed 2. The position of needle 5 in the back needle bed 2 is still the same as in FIG. 1, but needle 3 has been lifted by a higher nose, i.e., the loop expanding nose 25 on a transfer cam 23 (see FIGS. 7 and 8) into a loop expanding position. The loop expanding position is the highest position of the needle 3 during its loop transferring motions. In this position the loop 9 of the fabric 4 that is to be transferred rests on a loop supporting shoulder 10 and is fully expanded by an expander 8 attached to one side of the needle.
In the stage shown in FIG. 3 the needle 3 has been slightly lowered from its position in FIG. 2. It now rests on a lower nose, i.e., the transfer nose 26 of the transfer cam 23 and it is in its loop transferring position proper. In this position the loop 9 that is to be transferred is able in the course of the transferring action to open the latch 6 of the receiving needle 5. The position of needle 5 is still the same as that which it occupied in FIGS. 1 and 2.
In FIG. 4 the transferring needle is in the same position as in FIG. 3. In other words, it is still held by the transfer nose 26 in loop transferring position. The receiving needle 5 is now in a position immediately prior to being lifted by a cam associated with the back needle bed 2, for instance, by the transfer cam 21 shown in FIG. 7. The needle 5 has entered the gap between the expander 8 and the needle 3 and faces the expanded loop 9 on needle 3.
In FIG. 5 the position of needle 3 is still unchanged in loop transferring position, but the receiving needle 5 has been raised further, causing the transferred loop 9 to slide over the needle hook 7 and to open the latch 6.
In FIG. 6 the transferring needle 3 is still in transferring position, but the receiving needle 5 has now been lifted to the highest position necessary for retaining the loop 9. If first needle 3 and the needle 5 are lowered the transferred loop 9 will remain hanging in the hook of needle 5 for further knitting.
FIG. 7 is a schematic plan view of a front loop transferring cam set 12 and of a back loop transferring cam set 13. These loop transferring cam sets 12 and 13 are mounted on the cam carriage of the flat knitting machine on the left and right hand sides alongside the associated stitch cam sets. Their purpose is to impart the necessary movements to the needles 3 and 5 in the front and back needle beds 1 and 2 to cause a loop 9 to be transferred from needle 3 to needle 5 in the manner that has been described with reference to FIGS. 1 to 6. The loop itself causes the latch 6 of needle 5 which covers the point of the needle hook 7 with its spoon 11 to be automatically opened as exemplified in FIG. 5 Loop transfer with the aid of the loop transferring cam sets 12 and 13 takes place during carriage traverse to the right or left in leading or trailing position.
FIG. 7 shows that the front transferring cam set 12 contains a transfer cam 23 having an expanding nose 25 and symmetrically preceding and following the same a lower transfer nose 26 with depressions of equal depth between nose 25 and each nose 26. For lifting a needle that is to receive a loop, receiving cams 19 and 20 are provided. Furthermore, cams 15 and 16 serve to guide the needles to the transfer cam 23.
The back loop transferring cam set 13 is symmetrical with reference to the center axis of the carriage to the front loop transferring cam set 12. Instead of the transfer cam 23 in the front cam set 12 a transfer cam 24 is provided and comprises one loop expanding nose 25 and two transfer noses 26 which are lower than the expanding nose. The back loop transferring cam set 13 further comprises cams 17 and 18 which correspond to the cams 15 and 16 as well as receiving cams 21 and 22 which correspond to the receiving cams 19 and 20. The needle butts are represented in FIG. 7 by short parallel lines.
When the carriage traverses for instance from right to left and the loops are transferred from front to back, as assumed in FIG. 7, then the needles 3 are guided either by cam 15 or by a jacquard mechanism directly to the transfer cam 23. The needles 3 are driven over the leading transfer nose 26 and lifted to clearing height. They are then brought back by the expanding nose 25 to loop expanding height and finally by the trailing transfer nose 26 to transferring and latch opening height. During this needle movement from the expanding nose 25 to the trailing transfer nose 26 the needles 5 in the back needle bed 2 are thrown up by cam 21 into position for receiving the loop. It will be clearly observed that cam 21 in the back cam set 13 follows the trailing transfer nose 26 in the front cam set 12 and that the working ranges of the trailing transfer nose 26 in the front cam set 12 and of cam 21 in the back cam set 13 overlap.
If the cam system illustrated in FIG. 7 is to transfer all the loops from the needles 3 in the front needle bed to the needles 5 in the back needle bed 2, then the cams 17 and 18 and the receiving cam 22 in the back cam set 13 must be inactivated. If only specified needles 3, e.g., needles in the front bed selected by a jacquard mechanism are to transfer their loops to needles 5 in the back needle bed, then the cams 15 and 16 as well as the receiving cams 17 and 18 and the receiving cam 22 in the back cam set 13 must be inactivated.
FIG. 8 illustrates an alternative embodiment of a front loop transferring cam set 12. The associated back cam set 13 is correspondingly designed. In the modified loop transferring cam set 12 in FIG. 8 there is provided a transfer cam 23 which has a single lower transfer nose 26 and and leading as well as trailing higher loop expanding noses 25 with depressions of equal depth between nose 26 and each nose 25. The other cams of the set are adapted to the modified design of the transfer cam 23. Moreover, the loop transferring action generated by the modified transfer cam 23 corresponds to that already described with reference to FIGS. 1 to 7.
The height of cam 25 is determined in accordance with the needle gauge. | A flat knitting machine has two opposed needle beds and rigid loop expanders are provided on the needles. Loop transferring cam sets mounted on the traversing machine carriage include a transfer cam having at least three noses of which at least one is higher than the others. The higher nose lifts the needles sufficiently for the knitted loops held on the needles of one bed to be expanded on the loop expanders and the other noses complete transfer of the loops to the needles in the other bed. The loops open the latches of the receiving needles as they are transferred. | 3 |
[0001] The present application claims the benefit of priority under 35 USC §119(e) to U.S. Provisional Patent Application 60/585,757, which is hereby incorporated, in its entirety, herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to the papermaking art and, in particular, to the manufacture of paper substrates, paper-containing articles such as file folders, having improved reduction or inhibition in the growth of microbes, mold and/or fungus.
BACKGROUND OF THE INVENTION
[0003] Heavy weight cellulosic paper and paperboard webs and products made from the same such as file folders and paperboard file containers are often subject to damage during growth of microbes such as mold and fungus during storage long term storage. The prevalence of microbial growth increases as the storage time increases. During microbial growth, many aesthetic properties of the paper substrate are diminished and further the materials may become soggy, warped and/or weakened thereby reducing their usefulness and potentially allowing the microbes to contact and damage documents which may be stored in containers made with the paper or paperboard materials.
[0004] Internal, e.g. the addition of agents to the paper making process prior to the size press (e.g. wet end) and/or surface sizing, e.g., the addition of agents to the surface of a paper sheet that has been at least partially dried, are widely practiced in the paper industry, particularly for printing grades to improved the quality thereof. Some functional agents include, but are not limited to the most widely used additive: starch. However, starch alone has not been effective in preventing microbial growth on paper substrates and products containing the same. In fact, starch may actually promote microbial growth on paper substrates and products containing the same.
[0005] Examples of applying antimicrobial chemistries to cellulose-containing articles can be found in U.S. Pat. No. 3,936,339, which is hereby incorporated, in its entirety, herein by reference. However, the articles according to this reference are related to packaging materials.
[0006] Examples of applying antimicrobial chemistries to gypsum board can be found in US Patent Application Publication Nos. 20020083671; 20030037502 and 20030170317, all of which are hereby incorporated, in their entirety, herein by reference. All of which pertain to gypsum containing products.
[0007] While all of the above examples aid to provide materials with antimicrobial tendency by applying antimicrobial chemistries and compounds to the material and/or components thereof, none sufficiently provide for a paper substrate that is acceptable by commercial market standards in a manner that inhibits, retards, and/or resists antimicrobial growth over an acceptable duration of time, nor do they provide for an acceptable method of making and using the same.
[0008] Accordingly, there exists a need for a paper substrate and articles made therefrom that inhibit, retard, and/or resist microbial growth over an acceptable duration of time so as to provide, in part, paper articles and paper-based containers having improved aesthetic properties, durability and capacity to protect articles contained thereby.
SUMMARY OF THE INVENTION
[0009] One aspect of the invention relates to a paper substrate containing a web of cellulose fibers and an antimicrobial compound, where the antimicrobial compound is approximately dispersed evenly throughout from 100% to 5% of the web, including methods of making and using the same. An embodiment thereof relates to an antimicrobial compound that inhibits, retards, or reduces the growth of mold or fungus on or in the paper substrate. An additional embodiment thereof relates to the paper substrate containing from 1 to 5000 ppm dry weight of the antimicrobial compound based upon the total weight of the paper substrate. The compound may be approximately dispersed evenly throughout the web. Still further, an additional embodiment of the invention includes instances when the antimicrobial compound contains silver, zinc, an isothiazolone-containing compound, a benzothiazole-containing compound, a triazole-containing compound, an azole-containing compound, a benzimidazol-containing compound, a nitrile containing compound, alcohol-containing compound, a silane-containing compound, a carboxylic acid-containing compound, a glycol-containing compound, a thiol-containing compound, or mixtures thereof.
[0010] Another aspect of the present invention relates to a file folder containing any of the above-mentioned and/or below-mentioned paper substrates. In an embodiment of the present invention, the file folder may further have at least one die-cut edge.
[0011] Another aspect of the present invention relates to a file folder containing a web of cellulose fibers and an antimicrobial compound, where the antimicrobial compound is approximately dispersed evenly throughout from 100% to 5% of the web, including methods of making and using the same. One embodiment thereof is a file folder having at least one die-cut edge, as well as methods of making and using the same.
[0012] Another aspect of the present invention relates to a paper substrate, containing a first layer comprising a web of cellulose fibers; and a size-press applied coating layer in contact with at a portion of at least one surface of the first layer, where the coating layer contains an antimicrobial compound and where from 0.5 to 100% of the coating layer interpenetrates the first layer, as well as methods of making and using the same. In an embodiment thereof, the antimicrobial compound inhibits, retards, or reduces the growth of mold or fungus on or in the paper substrate. In a further embodiment of the present invention, the paper substrate contains from 1 to 5000 ppm dry weight of the antimicrobial compound. Still further, an additional embodiment relates to a paper substrate in which the antimicrobial compound is inorganic, organic, or mixtures thereof. Still further, an additional embodiment relates to paper substrate in which lies an antimicrobial contains silver, zinc, an isothiazolone-containing compound, a benzothiazole-containing compound, a triazole-containing compound, an azole-containing compound, a benzimidazol-containing compound, a nitrile containing compound, alcohol-containing compound, a silane-containing compound, a carboxylic acid-containing compound, a glycol-containing compound, a thiol-containing compound or mixtures thereof.
[0013] Another aspect of the present invention relates to a paper substrate containing a first layer comprising a web of cellulose fibers and a starch-based size-press applied coating layer in contact with at a portion of at least one surface of the first layer, where the coating layer contains an antimicrobial compound and where from 0.5 to 100% of the coating layer interpenetrates the first layer, as well as methods of making and using the same.
[0014] Another aspect of the present invention relates to a file folder containing a first layer comprising a web of cellulose fibers; and a size-press applied coating layer in contact with at a portion of at least one surface of the first layer, where the coating layer contains an antimicrobial compound and where from 0.5 to 100% of the coating layer interpenetrates the first layer, as well as methods of making and using the same. One embodiment thereof is a file folder having at least one die-cut edge, as well as methods of making and using the same.
[0015] Another aspect of the present invention relates to a method of making a paper substrate by contacting cellulose fibers with an antimicrobial compound during or prior to a papermaking process. One embodiment of the present invention includes instances where the cellulose fibers are contacted with the antimicrobial compound at the wet end of the papermaking process, thin stock, thick stock, machine chest, the headbox, size press, coater, shower, sprayer, steambox, or a combination thereof. Another embodiment of the present invention includes making paper articles and/or paper packages from the above-mentioned substrates, including file folders that may be die-cut.
[0016] Another aspect of the present invention relates to a method of making a paper substrate by contacting cellulose fibers with an antimicotic or fungicide during or prior to a papermaking process where the contacting occurs at the size press and produces a paper substrate comprising a first layer comprising a web of cellulose fibers and a size-press applied coating layer in contact with at a portion of at least one surface of the first layer so that from 25 to 75% of the size-press applied coating layer interpenetrates the first layer. Another embodiment of the present invention includes making paper articles and/or paper packages from the above-mentioned substrates, including file folders that may be die-cut.
[0017] Another aspect of the present invention relates to A method of making a paper substrate by contacting cellulose fibers with an antimicrobial compound during or prior to a papermaking process, where the contacting occurs at the wet end of the papermaking process and produces a paper substrate comprising a web of cellulose fibers and an antimicrobial compound and where the antimicrobial compound is approximately dispersed evenly throughout the web. Another embodiment of the present invention includes making paper articles and/or paper packages from the above-mentioned substrates, including file folders that may be die-cut.
[0018] The present invention relates to any and all paper or paperboard articles, including packages and packaging materials that may contain the paper substrates of the present invention.
[0019] Additional aspects and embodiments of the present invention are described hereinbelow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 : A first schematic cross section of just one exemplified embodiment of the paper substrate that is included in the paper substrate of the present invention.
[0021] FIG. 2 : A second schematic cross section of just one exemplified embodiment of the paper substrate that is included in the paper substrate of the present invention.
[0022] FIG. 3 : A third schematic cross section of just one exemplified embodiment of the paper substrate that is included in the paper substrate of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The inventors of the present technology have discovered an paper substrate, paperboard material, and articles such as packaging and packaging materials made therefrom, all having antimicrobial tendency by applying antimicrobial chemistries and compounds to the material and/or components thereof. Further, the paper or paperboard substrate of the present invention inhibits, retards, and/or resists antimicrobial growth over an acceptable duration of time.
[0024] The paper substrate of the present invention may contain recycled fibers and/or virgin fibers. Recycled fibers differ from virgin fibers in that the fibers have gone through the drying process several times.
[0025] The paper substrate of the present invention may contain from 1 to 100 wt %, preferably from 50 to 100 wt %, most preferably from 80 to 100 wt % of cellulose fibers based upon the total weight of the substrate, including 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 99 wt %, and including any and all ranges and subranges therein. More preferred amounts of cellulose fibers range from wt %.
[0026] Preferably, the sources of the cellulose fibers are from softwood and/or hardwood. The paper substrate of the present invention may contain from 1 to 99 wt %, preferably from 5 to 95 wt %, cellulose fibers originating from softwood species based upon the total amount of cellulose fibers in the paper substrate. This range includes 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 wt %, including any and all ranges and subranges therein, based upon the total amount of cellulose fibers in the paper substrate.
[0027] The paper substrate of the present invention may contain from 1 to 99 wt %, preferably from 5 to 95 wt %, cellulose fibers originating from hardwood species based upon the total amount of cellulose fibers in the paper substrate. This range includes 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 wt %, including any and all ranges and subranges therein, based upon the total amount of cellulose fibers in the paper substrate.
[0028] Further, the softwood and/or hardwood fibers contained by the paper substrate of the present invention may be modified by physical and/or chemical means. Examples of physical means include, but is not limited to, electromagnetic and mechanical means. Means for electrical modification include, but are not limited to, means involving contacting the fibers with an electromagnetic energy source such as light and/or electrical current. Means for mechanical modification include, but are not limited to, means involving contacting an inanimate object with the fibers. Examples of such inanimate objects include those with sharp and/or dull edges. Such means also involve, for example, cutting, kneading, pounding, impaling, etc means.
[0029] Examples of chemical means include, but is not limited to, conventional chemical fiber modification means including crosslinking and precipitation of complexes thereon. Examples of such modification of fibers may be, but is not limited to, those found in the following U.S. Pat. Nos. 6,592,717, 6,592,712, 6,582,557, 6,579,415, 6,579,414, 6,506,282, 6,471,824, 6,361,651, 6,146,494, H1,704, 5,731,080, 5,698,688, 5,698,074, 5,667,637, 5,662,773, 5,531,728, 5,443,899, 5,360,420, 5,266,250, 5,209,953, 5,160,789, 5,049,235, 4,986,882, 4,496,427, 4,431,481, 4,174,417, 4,166,894, 4,075,136, and 4,022,965, which are hereby incorporated, in their entirety, herein by reference.
[0030] The paper substrate of the present invention may contain an antimicrobial compound.
[0031] Antimicotics, fungicides are examples of antimicrobial compounds. Antimicrobial compounds may retard, inhibit, reduce, and/or prevent the tendency of microbial growth over time on/in a product containing such compounds as compared to that tendency of microbial growth on/in a product not containing the antimicrobial compounds. The antimicrobial compound when incorporated into the paper substrate of the present invention preferably retards, inhibits, reduces, and/or prevents microbial growth for a time that is at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 700, 800, 900, 1000% greater than that of a paper substrate that does not contain an antimicrobial compound, including all ranges and subranges therein.
[0032] Antimicotic compounds are, in part, mold resistant. Fungicide compounds are, in part, fungus resistant. The antimicrobial compound may have other functions and activities than provide either mold resistance and/or fungus resistance to a product containing the same.
[0033] The antimicrobial compound may also be mildew, bacteria and/or virus resistant. A mold specifically targeted, but meant to be non-limiting, is Black mold as applied to the above-mentioned paper substrate of the present invention.
[0034] It is preferable for the antimicotic and/or fungicide to be effective to be able to be applied in aqueous solution and/or suspension at the coater and/or head box and/or size press. Further it is preferable for the antimicotic and/or fungicide to not be highly toxic to humans.
[0035] The antimicotic and/or fungicide may be water insoluble and/or water soluble, most preferably water insoluble. The antimicotic and/or fungicide may be volatile and/or non-volatile, most preferably non-volatile. The antimicotic and/or fungicide may be organic and/or inorganic. The antimicotic and/or fungicide may be polymeric and/or monomeric.
[0036] The antimicotic and/or fungicide may be multivalent which means that the agent may carry one or more active compounds so as to protect against a wider range of mold, mildew and/or fungus species and to protect from evolving defense mechanisms within each species of mold, mildew and/or fungus.
[0037] Any water-soluble salt of pyrithione having antimicrobial properties is useful as the antimicrobial compound. Pyrithione is known by several names, including 2 mercaptopyridine-N-oxide; 2-pyridinethiol-1-oxide (CAS Registry No. 1121-31-9); 1-hydroxypyridine-2-thione and 1 hydroxy-2(1H)-pyridinethione (CAS Registry No. 1121-30-8). The sodium derivative, known as sodium pyrithione (CAS Registry No. 3811-73-2), is one embodiment of this salt that is particularly useful. Pyrithione salts are commercially available from Arch Chemicals, Inc. of Norwalk, Conn., such as Sodium OMADINE or Zinc OMADINE.
[0038] Examples of the antimicrobial compound may include silver-containing compound, zinc-containing compound, an isothiazolone-containing compound, a benzothiazole-containing compound, a triazole-containing compound, an azole-containing compound, a benzimidazol-containing compound, a nitrile containing compound, alcohol-containing compound, a silane-containing compound, a carboxylic acid-containing compound, a glycol-containing compound, a thiol-containing compound or mixtures thereof
[0039] Additional exemplified commercial antimicrobial compounds may include those from Intace including B-6773 and B-350, those from Progressive Coatings VJ series, those from Buckman Labs including Busan 1218, 1420 and 1200WB, those from Troy Corp including Polyphase 641, those from Clariant Corporation, including Sanitized TB 83-85 and Sanitized Brand T 96-21, and those from Bentech LLC incuding Preservor Coater 36. Others include AgION (silver zeolite) from AgION and Mircroban from Microban International (e.g. Microban additive TZ1, 52470, and PZ2). Further examples include dichloro-octyl-isothiazolone, Tri-n-butylin oxide, borax, G-4, chlorothalonil, organic fungicides, and silver-based fungicides. Any one or more of these agents would be considered satisfactory as an additive in the process of making paper material. Further commercial products may be those from AEGIS Environments (e.g. AEM 5772 Antimicrobial), from BASF Corporation (e.g. propionic acid), from Bayer (e.g. Metasol TK-100, TK-25), those from Bendiner Technologies, LLC, those from Ondei-Nalco (e.g. Nalcon 7645 and 7622), and those from Hercules (e.g. RX 8700, RX 3100, and PR 1912). The MSDS's of each and every commercial product mentioned above is hereby incorporated by reference in its entirety.
[0040] Still further, examples of the antimicrobial compounds may include silver zeolite, diehloro-octyl-isothiazolone, 4,5-dichloro-2-n-octyl-3(2H)-isothiazolone, 5-chloro-2-methyl-4-isothiazolin-3-one, 1,2-benzothiazol-3(2H)-one, poly[oxyethylene(ethylimino)ethylene dichloride], Tri-n-butylin oxide, borax, G-4, chlorothalonil, Alkyl-dimethylbenzyl-ammonium saccharinate, dichloropeyl-propyl-dioxolan-methlyl-triazole, alpha-chlorphenyl, ethyl-dimethylethyl-trazole-ethanol, benzimidazol, 2-(thiocyanomethythio)benzothiazole, alpha-2(-4-chlorophenyl)ethyl)-alpha-(1-1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol, (1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl]-1H-1,2,4-triazole, alkyl dimethylbenzyl ammonium saccharinate, 2-(methoxy-carbamoyl)-benzimidazol, tetracholorisophthalonitrile, P-[(diiodomethyl) sulfonyl]toluol, methyl alcohol, 3-(trimethoxysilyl) propyldimethyl octadecyl ammonium chloride, chloropropyltrimethylsilane, dimethyl octadecyllamine, propionic acid, 2-(4-thiazolyl)benzimidazole, 1,2-benzisothiazolin-3-one,2-N-octyl-4-isthiazolin-3-one, diethylene glycol monoethyl ether, ethylene glycol, propylene glycol, hexylene glycol, tributoxyethyl phosphate, 2-pyridinethio-1-oxide, potassium sorbate, diiodomethyl-p-tolysulfone, citric acid, lemon grass oil, and thiocyanomethythio-benzothiazole.
[0041] The antimicrobial compound may be present in the paper substrate at amounts from 1 to 5000 ppm dry weight, more preferably, from 100 to 3000 ppm dry weight, most preferably 50 to 1500 ppm dry weight. The amounts of antimicotic and/or fungicide may be 2, 5, 10, 25, 50, 75, 100, 12, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3200, 3500, 3750, 4000, 4250, 4500, 4750, and 5000 ppm dry weight based upon the total weight of the paper substrate, including all ranges and subranges therein. Higher amounts of such antimicotic and/or fungicide may also prove produce an antibacterial paper material and article therefrom as well. These amount are based upon the total weight of the paper substrate.
[0042] The paper substrate of the present invention, when containing the web of cellulose fibers and an antimicrobial compound, may contain them in a manner in which the antimicrobial compound is on the surface of or within from 1 to 100% of the web. The paper substrate may contain the antimicrobial compound on the surface of and/or within 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100% of the web, including all ranges and subranges therein.
[0043] When the antimicrobial compound is present on at least one surface of the web, it is preferable that the antimicrobial compound also be within 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100% of the web, including all ranges and subranges therein.
[0044] In another embodiment, it is preferable that, when the antimicrobial compound is within the web, it is approximately dispersed evenly throughout 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100% of the web. However, concentration gradients of the antimicrobial compound may occur within the web as a function of the cross section of the web itself. Such gradients are dependent upon the methodology utilized to make this product. For instance, the concentration of the antimicrobial compound may increase as the distance from a center portion of the cross-section of the web increases. That is, the concentration increases as one approaches the surface of the web. Further, the concentration of the antimicrobial compound may decrease as the distance from a center portion of the cross-section of the web decreases. That is, the concentration decreases as one approaches the surface of the web. Still further, the concentration of the antimicrobial compound is approximately evenly distributed throughout the portion of the web in which it resides. All of the above embodiments may be combined with each other, as well as with an embodiment in which the antimicrobial compound resides on at least one surface of the web.
[0045] FIGS. 1-3 demonstrate different embodiments of the paper substrate 1 in the paper substrate of the present invention. FIG. 1 demonstrates a paper substrate 1 that has a web of cellulose fibers 3 and a composition containing an antimicrobial compound 2 where the composition containing an antimicrobial compound 2 has minimal interpenetration of the web of cellulose fibers 3 . Such an embodiment may be made, for example, when an antimicrobial compound is coated onto a web of cellulose fibers.
[0046] FIG. 2 demonstrates a paper substrate 1 that has a web of cellulose fibers 3 and a composition containing an antimicrobial compound 2 where the composition containing an antimicrobial compound 2 interpenetrates the web of cellulose fibers 3 . The interpenetration layer 4 of the paper substrate 1 defines a region in which at least the antimicrobial compound penetrates into and is among the cellulose fibers. The interpenetration layer may be from 1 to 99% of the entire cross section of at least a portion of the paper substrate, including 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 99% of the paper substrate, including any and all ranges and subranges therein. Such an embodiment may be made, for example, when an antimicrobial compound is added to the cellulose fibers prior to a coating method and may be combined with a subsequent coating method if required. Addition points may be at the size press, for example.
[0047] FIG. 3 demonstrates a paper substrate 1 that has a web of cellulose fibers 3 and an antimicrobial compound 2 where the antimicrobial compound 2 is approximately evenly distributed throughout the web of cellulose fibers 3 . Such an embodiment may be made, for example, when an antimicrobial compound is added to the cellulose fibers prior to a coating method and may be combined with a subsequent coating method if required. Exemplified addition points may be at the wet end of the paper making process, the thin stock, and the thick stock.
[0048] The web of cellulose fibers and the antimicrobial compound may be in a multilayered structure. The thicknesses of such layers may be any thickness commonly utilized in the paper making industry for a paper substrate, a coating layer, or the combination of the two. The layers do not have to be of approximate equal size. One layer may be larger than the other. One preferably embodiment is that the layer of cellulose fibers has a greater thickness than that of any layer containing the antimicrobial compound. The layer containing the cellulose fibers may also contain, in part, the antimicrobial compound.
[0049] The density, basis weight and caliper of the web of this invention may vary widely and conventional basis weights, densities and calipers may be employed depending on the paper-based product formed from the web. Paper or paperboard of invention preferably have a final caliper, after calendering of the paper, and any nipping or pressing such as may be associated with subsequent coating of from about 1 mils to about 35 mils although the caliper can be outside of this range if desired. More preferably the caliper is from about 4 mils to about 20 mils, and most preferably from about 7 mils to about 17 mils. The caliper of the paper substrate with or without any coating may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 20, 22, 25, 27, 30, 32, and 35, including any and all ranges and subranges therein.
[0050] Paper substrates of the invention preferably exhibit basis weights of from about 10 lb/3000 ft 2 to about 500 lb/3000 ft 2 , although web basis weight can be outside of this range if desired. More preferably the basis weight is from about 30 lb/3000 ft 2 to about 200 lb/3000 ft 2 , and most preferably from about 35 lb/3000 ft 2 to about 150 lb/3000 ft 2 . The basis weight may be 10, 12, 15, 17, 20, 22, 25, 30, 32, 35, 37, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 500 lb/3000 ft 2 , including any and all ranges and subranges therein.
[0051] The final density of the papers may be calculated by any of the above-mentioned basis weights divided by any of the above-mentioned calipers, including any and all ranges and subranges therein. Preferably, the final density of the papers, that is, the basis weight divided by the caliper, is preferably from about 6 lb/3000 ft 2 /mil to about 14 lb/3000 ft 2 /mil although web densities can be outside of this range if desired. More preferably the web density is from about 7 lb/3000 ft 2 /mil to about 13 lb/3000 ft 2 /mil and most preferably from about 9 lb/3000 ft 2 /mil to about 12 lb/3000 ft 2 /mil.
[0052] The paper substrate of the present invention containing the web and the antimicrobial compound has the capability to retard, inhibit, reduce, and/or prevent the tendency of microbial growth over time on/in its web containing such compounds as compared to that tendency of microbial growth on/in a product not containing the antimicrobial compound. Further, the paper substrate of the present invention may also bestow such tendency on additional materials of which it may comprise and/or with which it may be in contact. Still further, the paper substrate of the present invention may also bestow this tendency upon any article, packaging, and/or packaging of which it may eventually be a component therein.
[0053] The article, packaging, and/or packaging of the present invention may have an antimicrobial tendency that preferably retards, inhibits, reduces, and/or prevents microbial growth for a time that is at least 5% greater than that of an article, packaging, and/or packaging that does not contain an antimicrobial compound. Preferably, such tendency is at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 700, 800, 900, 1000% greater than that of a article, packaging, and/or packaging that does not contain an antimicrobial compound, including all ranges and subranges therein.
[0054] The paper substrate's antimicrobial tendency may be measured in part by ASTM standard testing methodologies such as D 2020-92, E 2180-01, G 21-966, C1338, and D2020, all of which can be found as published by ASTM and all of which are hereby incorporated, in their entirety, herein by reference.
[0055] Textbooks such as those described in the “handbook for pulp and paper technologists” by G. A. Smook (1992), Angus Wilde Publications, which is hereby incorporated, in its entirety, by reference. Further, G. A. Smook referenced above and references cited therein provide lists of conventional additives that may be contained in the paper substrate, and therefore, the paper articles of the present invention. Such additives may be incorporated into the paper, and therefore, the paper packaging (and packaging materials) of the present invention in any conventional paper making process according to G. A. Smook referenced above and references cited therein.
[0056] The paper substrate of the present invention may also include optional substances including retention aids, sizing agents, binders, fillers, thickeners, and preservatives. Examples of fillers include, but are not limited to; clay, calcium carbonate, calcium sulfate hemihydrate, and calcium sulfate dehydrate. Examples of binders include, but are not limited to, polyvinyl alcohol, polyamide-epichlorohydrin, polychloride emulsion, modified starch such as hydroxyethyl starch, starch, polyacrylamide, modified polyacrylamide, polyol, polyol carbonyl adduct, ethanedial/polyol condensate, polyamide, epichlorohydrin, glyoxal, glyoxal urea, ethanedial, aliphatic polyisocyanate, isocyanate, 1,6 hexamethylene diisocyanate, diisocyanate, polyisocyanate, polyester, polyester resin, polyacrylate, polyacrylate resin, acrylate, carboxymethyl cellulose, urea, sodium nitrate, and methacrylate. Other optional substances include, but are not limited to silicas such as colloids and/or sols. Examples of silicas include, but are not limited to, sodium silicate and/or borosilicates. Another example of optional substances is solvents including but not limited to water.
[0057] The paper substrate of the present invention may contain retention aids selected from the group consisting of coagulation agents, flocculation agents, and entrapment agents dispersed within the bulk and porosity enhancing additives cellulosic fibers.
[0058] Retention aids for the bulk-enhancing additives to retain a significant percentage of the additive in the middle of the paperboard and not in the periphery. Suitable retention aids function through coagulation, flocculation, or entrapment of the bulk additive. Coagulation comprises a precipitation of initially dispersed colloidal particles. This precipitation is suitably accomplished by charge neutralization or formation of high charge density patches on the particle surfaces. Since natural particles such as fines, fibers, clays, etc., are anionic, coagulation is advantageously accomplished by adding cationic materials to the overall system. Such selected cationic materials suitably have a high charge to mass ratio. Suitable coagulants include inorganic salts such as alum or aluminum chloride and their polymerization products (e.g. PAC or poly aluminum chloride or synthetic polymers); poly(diallyldimethyl ammonium chloride) (i.e., DADMAC); poly (dimethylamine)-co-epichlorohydrin; polyethylenimine; poly(3-butenyltrimethyl ammoniumchloride); poly(4-ethenylbenzyltrimethylammonium chloride); poly(2,3-epoxypropyltrimethylammonium chloride); poly(5-isoprenyltrimethylammonium chloride); and poly(acryloyloxyethyltrimethylammonium chloride). Other suitable cationic compounds having a high charge to mass ratio include all polysulfonium compounds, such as, for example the polymer made from the adduct of 2-chloromethyl; 1,3-butadiene and a dialkylsulfide, all polyamines made by the reaction of amines such as, for example, ethylenediamine, diethylenetriamine, triethylenetetraamine or various dialkylamines, with bis-halo, bis-epoxy, or chlorohydrin compounds such as, for example, 1-2 dichloroethane, 1,5-diepoxyhexane, or epichlorohydrin, all polymers of guanidine such as, for example, the product of guanidine and formaldehyde with or without polyamines. The preferred coagulant is poly(diallyldimethyl ammonium chloride) (i.e., DADMAC) having a molecular weight of about ninety thousand to two hundred thousand and polyethylenimene having a molecular weight of about six hundred to 5 million. The molecular weights of all polymers and copolymers herein this application are based on a weight average molecular weight commonly used to measure molecular weights of polymeric systems.
[0059] Another advantageous retention system suitable for the manufacture of the paper substrate of this invention is flocculation. This is basically the bridging or networking of particles through oppositely charged high molecular weight macromolecules. Alternatively, the bridging is accomplished by employing dual polymer systems. Macromolecules useful for the single additive approach are cationic starches (both amylase and amylopectin), cationic polyacrylamide such as for example, poly(acrylamide)-co-diallyldimethyl ammonium chloride; poly(acrylamide)-co-acryloyloxyethyl trimethylammonium chloride, cationic gums, chitosan, and cationic polyacrylates. Natural macromolecules such as, for example, starches and gums, are rendered cationic usually by treating them with 2,3-epoxypropyltrimethylammonium chloride, but other compounds can be used such as, for example, 2-chloroethyl-dialkylamine, acryloyloxyethyldialkyl ammonium chloride, acrylamidoethyltrialkylammonium chloride, etc. Dual additives useful for the dual polymer approach are any of those compounds which function as coagulants plus a high molecular weight anionic macromolecule such as, for example, anionic starches, CMC (carboxymethylcellulose), anionic gums, anionic polyacrylamides (e.g., poly(acrylamide)-co-acrylic acid), or a finely dispersed colloidal particle (e.g., colloidal silica, colloidal alumina, bentonite clay, or polymer micro particles marketed by Cytec Industries as Polyflex). Natural macromolecules such as, for example, cellulose, starch and gums are typically rendered anionic by treating them with chloroacetic acid, but other methods such as phosphorylation can be employed. Suitable flocculation agents are nitrogen containing organic polymers having a molecular weight of about one hundred thousand to thirty million. The preferred polymers have a molecular weight of about ten to twenty million. The most preferred have a molecular weight of about twelve to eighteen million. Suitable high molecular weight polymers are polyacrylamides, anionic acrylamide-acrylate polymers, cationic acrylamide copolymers having a molecular weight of about five hundred thousand to thirty million and polyethylenimenes having molecular weights in the range of about five hundred thousand to two million.
[0060] The paper substrate of the present invention may contain high molecular weight anionic polyacrylamides, or high molecular weight polyethyleneoxides (PEO). Alternatively, molecular nets are formed in the network by the reaction of dual additives such as, for example, PEO and a phenolic resin.
[0061] The paper substrate of the present invention may contain from 0.001 to 20 wt % of the optional substances based on the total weight of the substrate, preferably from 0.01 to 10 wt %, most preferably 0.1 to 5.0 wt %, of each of at least one of the optional substances. This range includes 0.001, 0.002, 0.005, 0.006, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, and 20 wt % based on the total weight of the substrate, including any and all ranges and subranges therein.
[0062] The optional substances may be dispersed throughout the cross section of the paper substrate or may be more concentrated within the interior of the cross section of the paper substrate. Further, other optional substances such as binders for example may be concentrated more highly towards the outer surfaces of the cross section of the paper substrate. More specifically, a majority percentage of optional substances such as binders may preferably be located at a distance from the outside surface of the substrate that is equal to or less than 25%, more preferably 10%, of the total thickness of the substrate.
[0063] An example of a binder is polyvinyl alcohol in combination with, for example, starch or alone such as polyvinyl alcohol having a % hydrolysis ranging from 100% to 75%. The % hydrolysis of the polyvinyl alcohol may be 75, 76, 78, 80, 82, 84, 85, 86, 88, 90, 92, 94, 95, 96, 98, and 100% hydrolysis, including any and all ranges and subranges therein.
[0064] The paper substrate of the present invention may then contain PVOH at a wt % of from 0.05 wt % to 20 wt % based on the total weight of the substrate. This range includes 0.001, 0.002, 0.005, 0.006, 0.008, 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, and 20 wt % based on the total weight of the substrate, including any and all ranges and subranges therein.
[0065] The paper substrate the present invention may contain a surface sizing agent such as starch and/or modified and/or functional equivalents thereof at a wt % of from 0.05 wt % to 20 wt %, preferably from 5 to 15 wt % based on the total weight of the substrate. The wt % of starch contained by the substrate may be 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, and 20 wt % based on the total weight of the substrate, including any and all ranges and subranges therein. Examples of modified starches include, for example, oxidized, cationic, ethylated, hydroethoxylated, etc. Examples of functional equivalents are, but not limited to, polyvinyl alcohol, polyvinylamine, alginate, carboxymethyl cellulose, etc.
[0066] Further, the starch may be of any type, including but not limited to oxidized, ethylated, cationic and pearl, and is preferably used in aqueous solution. Illustrative of useful starches for the practice of this preferred embodiment of the invention are naturally occurring carbohydrates synthesized in corn, tapioca, potato and other plants by polymerization of dextrose units. All such starches and modified forms thereof such as starch acetates, starch esters, starch ethers, starch phosphates, starch xanthates, anionic starches, cationic starches and the like which can be derived by reacting the starch with a suitable chemical or enzymatic reagent can be used in the practice of this invention.
[0067] Useful starches may be prepared by known techniques or obtained from commercial sources. For example, the suitable starches include PG-280 from Penford Products, SLS-280 from St. Lawrence Starch, the cationic starch CatoSize 270 from National Starch and the hydroxypropyl No. 02382 from Poly Sciences, Inc.
[0068] Preferred starches for use in the practice of this invention are modified starches. More preferred starches are cationic modified or non-ionic starches such as CatoSize 270 and KoFilm 280 (all from National Starch) and chemically modified starches such as PG-280 ethylated starches and AP Pearl starches. More preferred starches for use in the practice of this invention are cationic starches and chemically modified starches.
[0069] In addition to the starch, small amounts of other additives may be present as well in the size composition. These include without limitation dispersants, fluorescent dyes, surfactants, deforming agents, preservatives, pigments, binders, pH control agents, coating releasing agents, optical brighteners, defoamers and the like. Such additives may include any and all of the above-mentioned optional substances, or combinations thereof.
[0070] The paper substrate of the present invention may also include additives that render the paper substrate water resistant. Examples of such technologies include, but is not limited to those found in U.S. Pat. No. 6,645,642 and U.S. Ser. No. 10/685,899; and Ser. No. 10/430,244, which are hereby incorporated, in their entirety, herein by reference. The paper substrate of the present invention may be made as described herein and may be further made to account for these technologies in rendering a paper substrate that is both water-resistant and antimicrobial in tendency.
[0071] The paper substrate of the present invention may also include additives such as bulking agents. A particularly preferred bulking agent include expandable microspheres such as those described in U.S. Pat. Nos. 6,802,938; 6,846,529; 6,802,938; 5,856,389; and 5,342,649, as well as U.S. Ser. Nos. 10/121,301; 10/437,856; 10/967074; 10/967106; and 60/660703 which was filed Mar. 11, 2005, all of these references are hereby incorporated, in their entirety, herein by reference. The paper substrate of the present invention may be made as described herein and may be further made to account for these bulking technologies in rendering a paper substrate that comprises antimicrobial tendency, water resistance, and/or a bulking agent such as a preferably microsphere.
[0072] The paper substate of the present invention may be further combined with additional components in a manner that makes it useful as a paper facing for insulation which, in turn, may be utilized as a component and/or in a component for constructions such as homes, residential buildings, commercial buildings, offices, stores, and industrial buildings. Accordingly, insulation paper facing as well as the above-mentioned constructions are also aspects of the present invention.
[0073] Exemplified articles made from the paper substrate of the present invention may include, but is not limited to, paper facing, envelopes, file folders, wall board tape, portfolios, folding cartons, food and beverage containers, etc. Any article containing a cellulose web and/or paper substrates may be made in a manner that incorporates the substrate of the present invention.
[0074] The paper substrate may be made by contacting the antimicrobial compound with the cellulose fibers consecutively and/or simultaneously. Still further, the contacting may occur at acceptable concentration levels that provide the paper substrate of the present invention to contain any of the above-mentioned amounts of cellulose and antimicrobial compound of the present invention isolated or in any combination thereof. More specifically, the paper substrate of the present application may be made by adding and amount that is from 1.5 to 150 times that of the amount of antimicrobial compound that is to be retained within the paper substrate based upon dry weight of the paper substrate with the cellulose fibers. This amount may be 1.5, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, and 125 times that of the amount of antimicrobial compound that is to be retained within the paper substrate based upon dry weight hereof with the cellulose fibers, including any and all ranges and subranges therein. In accordance with the present invention, the contacting may occur so that from 0.1 to 100% of the amount of antimicrobial added to the cellulose fibers based upon dry weight of the paper substrate. The amount retained may be 0.1, 0.2, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100% of the antimicrobial compound added to the cellulose fibers is retained in the paper substrate, including any and all ranges and subranges therein.
[0075] The contacting of the antimicrobial compound with the cellulose fibers may occur anytime in the papermaking process including, but not limited to the wet end, thick stock, thin stock, head box, size press and coater with the preferred addition point being at the thin stock. Further addition points include machine chest, stuff box, and suction of the fan pump.
[0076] The paper substrate may be made by contacting further optional substances with the cellulose fibers as well. The contacting may occur anytime in the papermaking process including, but not limited to the thick stock, thin stock, head box, size press, water box, and coater. Further addition points include machine chest, stuff box, and suction of the fan pump. The cellulose fibers, antimicrobial compound, and/or optional/additional components may be contacted serially, consecutively, and/or simultaneously in any combination with each other. The cellulose fibers and antimicrobial compound may be pre-mixed in any combination before addition to or during the paper-making process.
[0077] The paper substrate may be pressed in a press section containing one or more nips. However, any pressing means commonly known in the art of papermaking may be utilized. The nips may be, but is not limited to, single felted, double felted, roll, and extended nip in the presses. However, any nip commonly known in the art of papermaking may be utilized.
[0078] The paper substrate may be dried in a drying section. Any drying means commonly known in the art of papermaking may be utilized. The drying section may include and contain a drying can, cylinder drying, Condebelt drying, IR, or other drying means and mechanisms known in the art. The paper substrate may be dried so as to contain any selected amount of water. Preferably, the substrate is dried to contain less than or equal to 10% water.
[0079] The paper substrate may be passed through a size press, where any sizing means commonly known in the art of papermaking is acceptable. The size press, for example, may be a puddle mode size press (e.g. inclined, vertical, horizontal) or metered size press (e.g. blade metered, rod metered). At the size press, sizing agents such as binders may be contacted with the substrate. Optionally these same sizing agents may be added at the wet end of the papermaking process as needed. After sizing, the paper substrate may or may not be dried again according to the above-mentioned exemplified means and other commonly known drying means in the art of papermaking. The paper substrate may be dried so as to contain any selected amount of water. Preferably, the substrate is dried to contain less than or equal to 10% water.
[0080] The paper substrate may be calendered by any commonly known calendaring means in the art of papermaking. More specifically, one could utilize, for example, wet stack calendering, dry stack calendering, steel nip calendaring, hot soft calendaring or extended nip calendering, etc.
[0081] The paper hoard and/or substrate of the present invention may also contain at least one coating layer, including two coating layers and a plurality thereof. The coating layer may be applied to at least one surface of the paper board and/or substrate, including two surfaces. Further, the coating layer may penetrate the paper board and/or substrate. The coating layer may contain a binder. Further the coating layer may also optionally contain a pigment. Other optional ingredients of the coating layer are surfactants, dispersion aids, and other conventional additives for printing compositions.
[0082] The coating layer may contain a coating polymer and/or copolymer which may be branched and/or crosslinked. Polymers and copolymers suitable for this purpose are polymers having a melting point below 270° C. and a glass transition temperature (Tg) in the range of −150 to +120° C. The polymers and copolymers contain carbon and/or heteroatoms. Examples of suitable polymers may be polyolefins such as polyethylene and polypropylene, nitrocellulose, polyethylene terephthalate, Saran and styrene acrylic acid copolymers. Representative coating polymers include methyl cellulose, carboxymethyl cellulose acetate copolymer, vinyl acetate copolymer, styrene butadiene copolymer, and styrene-acrylic copolymer. Any standard paper board and/or substrate coating composition may be utilized such as those compositions and methods discussed in U.S. Pat. No. 6,379,497, which is hereby incorporated, in its entirety, herein by reference.
[0083] The coating layer may include a plurality of layers or a single layer having any conventional thickness as needed and produced by standard methods, especially printing methods. For example, the coating layer may contain a basecoat layer and a topcoat layer. The basecoat layer may, for example, contain low density thermoplastic particles and optionally a first binder. The topcoat layer may, for example, contain at least one pigment and optionally a second binder which may or may not be a different binder than the first. The particles of the basecoat layer and the at least one pigment of the topcoat layer may be dispersed in their respective binders.
[0084] The invention can be prepared using known conventional techniques. Methods and apparatuses for forming and applying a coating formulation to a paper substrate are well known in the paper and paperboard art. See for example, G. A. Smook referenced above and references cited therein all of which is hereby incorporated by reference. All such known methods can be used in the practice of this invention and will not be described in detail. For example, the mixture of essential pigments, polymeric or copolymeric binders and optional components can be dissolved or dispersed in an appropriate liquid medium, preferably water.
[0085] The paper substrate may be microfinished according to any microfinishing means commonly known in the art of papermaking. Microfinishing is a means involving frictional processes to finish surfaces of the paper substrate. The paper substrate may be microfinished with or without a calendering means applied thereto consecutively and/or simultaneously. Examples of microfinishing means can be found in United States Published Patent Application 20040123966 and references cited therein, which are all hereby, in their entirety, herein incorporated by reference.
[0086] The paper and paperboard web of this invention can be used in the manufacture of a wide range of paper-based products where microbial resistance is desired using conventional techniques. For example, paper and paperboard webs formed according to the invention may be utilized in a variety of office or clerical applications. The web is preferably used for making file folders, manila folders, flap folders such as Bristol base paper, and other substantially inflexible paperboard webs for use in office environments, including, but not limited to paperboard containers for such folders, and the like. The manufacture of such folders from paper webs is well known to those in the paper converting arts and consists in general of cutting appropriately sized and shaped blanks from the paper web, typically by “reverse” die cutting, and then folding the blanks into the appropriate folder shape followed by stacking and packaging steps. The blanks may also be scored beforehand if desired to facilitate folding. The scoring, cutting, folding, stacking, and packaging operations are ordinarily carried out using automated machinery well-known to those of ordinary skill on a substantially continuous basis from rolls of the web material fed to the machinery from an unwind stand.
[0087] Any and all additional methodologies of making a paper substrate may be utilized as found in conventional paper making arts such as that found in G. A. Smook referenced above and references cited therein, all of which is hereby incorporated by reference, so long as the antimicrobial compound is contacted with the cellulose fiber.
[0088] The paper substrate of the present invention, including any article and/or packaging material made therefrom is also expected to have a better performance under conditions that test wet-bleed, transfer, wet rub, wet smear, dry rub resistance, condensation rub resistance, chain lube rub resistance, product rub resistance, and adhesion by scratch resistance. Still further, the paper substrate of the present invention, including any article and/or packaging material made therefrom is also expected to have an increased antimicrobial tendency after such products are scraped, scratched, abraded, etc (as tested by such tests disclosed herein) as compared to those substrates, articles and packaging that do not contain the antimicrobial compound according to the present invention.
[0089] The present invention is explained in more detail with the aid of the following embodiment example which is not intended to limit the scope of the present invention in any manner.
EXAMPLES
Example 1
[0090] A paper facing paper substrate was made by pre-mixing 100 ppm of an active ingredient (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one) based upon dry weight tons with cellulose fibers during the paper making process.
[0091] The antimicrobial tendency of the paper substrate was tested using ASTM methods D 2020A. The results demonstrated that the paper substrate was resistant to Aspergillus niger, Aspergillus terreus , and Chaetomium globosum after two (2 weeks) by demonstrating no growth of such organisms and/or any other organisms during such time.
[0092] The antimicrobial tendency of the paper substrate was tested using ASTM C-1338-00. The results demonstrated that the paper substrate was resistant to Aspergillus niger, Aspergillus versicolor, Chaetomium globosum, Penicillium funiculosum , and Aspergillus flavus after 7 days by demonstrating no growth of such organisms and/or any other organisms during such time.
[0093] The antimicrobial tendency of the paper substrate was tested using ASTM G 21-96. The results demonstrated that the paper substrate was resistant to Aspirgillus niger, Penicillium pinophilum 14, Chaetomium globosum, Gliocladium virens , and Aureobasidium pullulans after 28 days by demonstrating no growth of such organisms and/or any other organisms during such time.
Example 2
[0094] A paper facing was made by adding standard asphalt to the paper facing paper substrate of Example 1. Then, the resultant paper facing was heated and fiberglass was applied thereto so as to simulate the process of making a paper facing insulation containing the paper substrate of Example 1, asphalt and fiberglass insulation. Both standard asphalt and asphalt treated with an antimicrobial compound as utilized in separate embodiments. The paper facings were tested using ASTM methods D 2020A and G 21-96.
[0095] After 7 days the paper facing of Example 2 containing standard asphalt had no growth on either the paper substrate and/or the asphalt as measured according to both the D 2020A and G 21-96 tests. After 14 days, the paper facing of Example 2 containing standard asphalt had no growth on the paper substrate according to the D 2020A test, but had heavy growth on the asphalt according to this test. After 14 days, the paper facing of Example 2 containing standard asphalt had slight growth according to the G 21-96 test. After 21 days, the paper facing of Example 2 containing standard asphalt had moderate growth according to the G 21-96 test. After 28 days, the paper facing of Example 2 containing standard asphalt had heavy growth according to the G 21-96 test
[0096] After 7 days the paper facing of Example 2 containing the treated asphalt had no growth on either the paper substrate and/or the asphalt as measured according to both the D 2020A and G 21-96 tests. After 14 days, the paper facing of Example 2 containing treated asphalt had no growth on the paper substrate, nor the asphalt according to the D 2020A test. After 14 days, the paper facing of Example 2 containing treated asphalt had no growth according to the G 21-96 test. After 21 days, the paper facing of Example 2 containing treated asphalt had slight growth according to the G 21-96 test. After 28 days, the paper facing of Example 2 containing treated asphalt had moderate growth according to the G 21-96 test.
Comparative Example 1
[0097] A paper facing containing a paper substrate, standard asphalt, and fiberglass insulation was made in parallel according to that process outlined in Example 2 except that the paper substrate did not contain any antimicrobial compound at all.
[0098] The paper facing of Comparative Example 1 had moderate growth everywhere after 7 days and heavy growth everywhere after 14 days according to the D 2020A test. Further the paper facing of Comparative Example 1 had moderate growth, heavy growth, heavy growth, and heavy growth everywhere after 7, 14, 21, and 28 days, respectively, according to the G 21-96 test.
Example 3
[0099] A file folder was made from a substrate in which Busan 1200 was added to cellulose fibers at the size press. The substrate was reverse die-cut.
Example 4
[0100] A file folder was made from a substrate in which Busan 1200 and a stearylated melamine/paraffin wax obtained commercially from RohmNova under the tradename Sequapel® 414 were both added to cellulose fibers at the size press. The substrate was reverse die-cut.
Comparative Example 2
[0101] A file folder was made from a standard substrate made from cellulose fibers and reverse die-cut. This is the standard control.
Example 5
[0102] As tested by the ASTM standard E2180-01 test, Examples 3 and 4 showed a 73.70% and 87.70% reduction in the growth of Staphylococcus aureus as compared to that of the Comparative Example 2.
Example 6
[0103] As tested by the ASTM standard D 2020-92 test, Examples 3 and 4 showed no growth after 7 and 14 days respectively of Aspergillus niger, Aspergillus terreus , and Chaetomium globosum . However, Comparative Example 2 had growth of Aspergillus niger, Aspergillus terreus , and Chaetomium globosum at both 7 and 14 days.
Example 7
[0104] After abrasion of a conventional file folder made of a paper substrate coated with Busan 1200, the file folder will fail ASTM D 2020 testing after 7 and 14 days as described above, while a file folder containing a substrate that contains Busan 1200 by application at the size press and/or the wet end of the papermaking process will not show growth of Aspergillus niger, Aspergillus terreus , and Chaetomium globosum after 7 and 14 days.
[0105] As used throughout, ranges are used as a short hand for describing each and every value that is within the range, including all subranges therein.
[0106] Numerous modifications and variations on the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the accompanying claims, the invention may be practiced otherwise than as specifically described herein.
[0107] U.S. patent application Ser. No. ______, filed Jul. 6, 2005, and also claiming 119(e) priority to U.S. Provisional Patent Application 60/585,757, is hereby incorporated, in its entirety, herein by reference.
[0108] All of the references, as well as their cited references, cited herein are hereby incorporated by reference with respect to relative portions related to the subject matter of the present invention and all of its embodiments | The invention relates to the papermaking art and, in particular, to the manufacture of paper substrates, paper-containing articles such as file folders, having improved reduction or inhibition in the growth of microbes, mold and/or fungus. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 14/919,486 filed Oct. 21, 2015, which is a continuation of U.S. application Ser. No. 13/646,277 filed on Oct. 5, 2012, which claims the benefit of U.S. Provisional Application No. 61/543,663, filed on Oct. 5, 2011, and U.S. Provisional Application No. 61/606,031, filed on Mar. 2, 2012, and U.S. Provisional Application No. 61/610,805, filed on Mar. 14, 2012. Each of these five applications is hereby incorporated by reference in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to offshore drilling and production platforms. More particularly, it relates to a method and apparatus for drilling a plurality of wells at a single platform (or vessel) location and installing production risers on those wells.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Both tension leg platforms (TLP's) and semi-submersible floating vessels (“semis”) can be used for offshore drilling and production operations.
An offshore drilling vessel (TLP) is a vertically moored floating structure typically used for the offshore production of oil and/or gas, and is particularly suited for water depths greater than about 1000 ft.
The platform is permanently moored by tethers or tendons grouped at each of the structure's corners. A group of tethers is called a tension leg. The tethers have relatively high axial stiffness (low elasticity) such that virtually all vertical motion of the platform is eliminated. This allows the platform to have the production wellheads on deck (connected directly to the subsea wells by rigid risers), instead of on the seafloor. This feature enables less expensive well completions and allows better control over the production from the oil or gas reservoir.
A semi-submersible is a particular type of floating vessel that is supported primarily on large pontoon-like structures that are submerged below the sea surface. The operating decks are elevated perhaps 100 or more feet above the pontoons on large steel columns. This design has the advantage of submerging most of the area of components in contact with the sea thereby minimizing loading from wind, waves and currents. Semi-submersibles can operate in a wide range of water depths, including deep water. The unit may stay on location using dynamic positioning (DP) and/or be anchored by means of catenary mooring lines terminating in piles or anchors in the seafloor. Semi-submersibles can be used for drilling, workover operations, and production platforms, depending on the equipment with which they are equipped. When fitted with a drilling package, they are typically called semi-submersible drilling rigs.
The DeepDraftSemi® vessel offered by SBM Offshore, Inc. (Houston, Tex.) is a semi-submersible fitted with oil and gas production facilities that is suitable for use in ultra-deep water conditions. The unit is designed to optimize vessel motions to accommodate steel catenary risers (SCRs).
BRIEF SUMMARY OF THE INVENTION
A floating, offshore drilling and/or production platform is equipped with a rail-mounted transport system that can be positioned at a plurality of selected positions over the well bay of the vessel. The transport system can move a drilling riser with a drilling riser tensioner system and a blowout preventer from one drilling location to another without removing them from the well bay of the vessel. Using the transport system, the drilling riser is lifted just clear of a first well head and positioned over an adjacent, second well head using guidelines. The transport system may then move the upper end of the drilling riser (together with its attached tensioner and BOP) to a second drilling location. A dummy wellhead may be provided on the seafloor in order to secure the lower end of the drilling riser without removing it from the sea while production risers are being installed.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
FIG. 1 is a perspective view of an isolated well bay on an offshore drilling platform according to one particular embodiment of the invention that provides for 27 production riser tensioners and up to nine locations of a moveable drilling riser tensioner and blowout preventer.
FIG. 2 shows the well bay illustrated in FIG. 1 installed in the lower deck (“production deck”) of a TLP.
FIGS. 3A-3C show both a production riser tensioner and surface tree assembly as well as a drilling riser tension joint, drilling riser tensioner and blowout preventer assembly on a transport trolley according to the invention. FIG. 3A is a top view of the two assemblies supported on a topside deck wellbay beam according to the invention. FIG. 3B is a side view of the two assemblies supported on a topside deck wellbay beam according to the invention. FIG. 3C is an end view of the drilling riser tension joint, drilling riser tensioner and blowout preventer assembly on the transport trolley.
FIGS. 4A-4D show various views of an adapter frame in the retracted (drilling) position within a transport trolley according to the invention. FIG. 4A is an isometric view of the adapter frame in the retracted position. FIG. 4B is a top view of the adapter frame in the retracted position. FIG. 4C is an end view of the adapter frame in the retracted position. FIG. 4D is a side view of the adapter frame in the retracted position.
FIGS. 5A-5D show various views of an adapter frame in the extended (transfer) position within a transport trolley according to the invention. FIG. 5A is an isometric view of the adapter frame in the extended position. FIG. 5B is a top view of the adapter frame in the extended position. FIG. 5C is an end view of the adapter frame in the extended position. FIG. 5D is a side view of the adapter frame in the extended position.
FIG. 6A-6D show various views of a transport trolley according to the invention. FIG. 6A is an isometric view of the transport trolley. FIG. 6B is a top view of the transport trolley. FIG. 6C is an end view of the transport trolley. FIG. 6D is a side view of the transport trolley.
FIG. 7A-7D show various views of an adaptor frame (or drilling riser support insert) according to the invention. FIG. 7A is an isometric view of the adaptor frame. FIG. 7B is a top view of the adaptor frame. FIG. 7C is an end view of the adaptor frame. FIG. 7D is a side view of the adaptor frame.
FIG. 8A-8E illustrate the sequential steps used in transferring a drilling riser between adjacent wells on the seafloor in a method according to the invention. FIG. 8A is an illustration of Step 1 of the method. FIG. 8B is an illustration of Step 2 of the method. FIG. 8C is an illustration of Step 3 of the method. FIG. 8D is an illustration of Step 4 of the method. FIG. 8E is an illustration of Step 5 of the method.
DETAILED DESCRIPTION OF THE INVENTION
The invention may best be understood by reference to one particular preferred embodiment whose apparatus is illustrated in FIGS. 1-7 and an associated method of use is illustrated in FIG. 8 as a sequence of steps. The drawing figures outline general equipment and methodology for drilling multiple wells from a floating unit, and the installation of production risers, while minimizing or eliminating the need to retrieve the drilling riser when moving between wells.
The system shown is intended for use on a well pattern which is essentially rectangular in shape, but it should be understood that similar methodology could be adapted to well patterns of a more square shape or other patterns.
One particular feature of the system is a transfer trolley, which is suspended from the lower deck (the production deck) of the floating platform. The transfer trolley is set to run down the length of the well pattern. The position of the transfer trolley is held side to side by fixed rails, or similar, which may form part of the deck structure. The end-to-end position of the transfer trolley may be shifted using a rack-and-pinion arrangement with the pinion(s) turned by hydraulic motors or the like. The end-to-end position of the transfer trolley may be controlled by other means—for example by a pair of opposing winches used to translate the transfer trolley.
The transfer trolley may be used to transport the assembled drilling riser together with an associated tensioner and blowout preventer (BOP) between well bay positions.
The production deck (the lower deck) of the floating structure may contain discrete (separate) tensioners 42 for the near-vertical production risers. These tensioners may be arranged in a regular geometric pattern, as shown in FIG. 1 . It should be noted that the spacing of the well bay on the structure may be chosen to be consistent with the physical requirements to fit production tensioners, surface trees, connection jumpers, and other required equipment for drilling, production, work over and so forth. The wells may be spaced on the seafloor to provide access space as required for various seafloor activities related to drilling, production, etc. The seafloor and surface spacing may not necessarily be identical (due to different space requirements) but may be established in a way to minimize the offset angles between corresponding seafloor and surface locations.
Referring in particular to FIGS. 1 and 2 , the TLP includes provision for installation of a total of 27 riser tensioners in a 9-by-3 array of well slots 20 on the lower deck 82 of a TLP. The drilling riser is deployed only from the central of the three columns, with the ability to reach each of the 27 subsea well head locations from at least one of the nine positions within the central column. For certain well patterns, less than the full 9 central column positions may be needed to reach each of the wells on the seafloor. The central column may initially be open to allow translation of the hanging drilling riser to locations appropriate for reaching the well heads. Production risers in the two outer columns may be installed first, with tensioners 42 and surface trees 40 mounted on the lower deck (production deck) 82 . As additional risers are added, inserts may be placed in the central column to allow installation of production riser tensioners therein. Tree access platforms 16 may be provided in production deck structure 18 . FIG. 1 shows the outer columns with all production risers installed, a single production riser installed at one end of the central column, and the drilling riser 36 near the midpoint of the central column. FIG. 1 also shows a smaller BOP 28 (used for well completion) on a Production Riser Tensioner 42 (connected to production riser tension joint 44 ) in the outer row adjacent to the larger drilling BOP 26 , confirming adequate clearance between the two BOP's.
FIG. 2 shows the production deck 82 of a TLP equipped with a drilling riser transport system according to the invention viewed from the opposite end of the well bay as that shown in FIG. 1 and with the topsides structure (drilling deck) in place. The two winches 22 shown at the near end of the opening in the lower deck 82 are for the drilling riser guidelines 24 . This view also shows the routing of the production 10 , annulus 14 and control jumpers 12 for each of the surface trees. These jumpers are routed outward on the two outer columns of wells. The boxes 84 above the central (open) column represent the tie off locations for the central wells. Note that there is ample clearance for hook up of hard piping to the drilling BOP 26 .
FIG. 3B is a side view of a drilling riser assembly comprising drilling riser tension joint 36 , a drilling riser tensioner system 30 and a high-pressure blowout preventer (BOP) 26 supported in a drilling riser transfer system 32 according to the invention.
As shown in FIG. 3A (a top plan view), the support inserts for both the production tensioners 42 and drilling riser tensioner 30 may rest on brackets 38 extending outward from the main beams 64 along the edges of the opening in the lower deck. The drilling riser 36 may be moved by means of a transporter 32 which fits around the Drilling Riser Transport (DRT) support insert 66 and can lift it clear of the support brackets 38 .
Also shown in the top and side views of FIG. 3 are winches 22 for guide wire ropes 24 . Winches 22 may be constant tension winches. Guide wire rope 24 may be routed around sheave 86 and through openings in drilling riser tensioner 30 and hole 62 (see FIG. 6 ) in transport trolley 32 .
As illustrated in FIG. 4 , the transporter 32 may move the drilling riser assembly ( 26 + 30 + 36 in FIG. 3 ) on rails 34 ( FIG. 1 ) by means of a rack-and-pinion drive system, located on the edges of the opening in the lower deck. Racks 70 may be attached to well bay support beams 64 and/or tracks 72 and pinions 68 may be mounted on transport trolley 32 and connected to hydraulic drive motors 52 . The transporter may be supported by HILMAN ROLLERS® roller mechanisms 54 (Hilman Inc., Marlboro, N.J. 07746) resting on horizontal tracks 72 . As shown in FIG. 4 , the drive system of the illustrated embodiment uses four drive motors. In addition, the motion of the transporter may be controlled by guide rollers (not shown) reacting on the sides of the track on one or both sides of the opening in the lower deck.
In FIG. 4 , adaptor frame 66 is shown in the retracted position. The extended position of the adaptor frame 66 is shown in phantom in FIG. 4C and FIG. 4D . When in the retracted position, the adaptor frame 66 is supported by deck support brackets 38 and not (to any significant degree) by transport trolley 32 . It will be appreciated that the retracted position of adaptor frame 66 is that used during drilling operations. When in the retracted position, the reactive force of the drilling riser tensioner system 30 is transmitted to the deck structure 64 via deck support brackets 38 . The supports of transport trolley 32 (e.g., Hilman rollers 54 and support arms 88 ) are not exposed to the dynamic loads of heave compensation imposed by tensioner system 30 .
FIG. 5 is similar to FIG. 4 , but with adaptor frame 66 in the extended position. As shown in FIG. 5 , the DRT support insert 66 may be lifted relative to the transporter 32 by four hydraulic cylinders 60 , two on each side of the insert. The geometric shape of the support insert and the transporter may be such that overlap between the two parts provides guidance as the support insert rises, limiting lateral loads on the hydraulic cylinders.
Extending adapter frame 66 results in lifting the drilling riser assembly sufficiently to clear the wellhead on the seafloor to which is was connected. This permits the drilling riser assembly to be moved horizontally within the well bay without disconnecting either the drilling BOP 26 or the drilling riser tensioner system 30 . Moreover, the drilling riser itself may remain in the sea. In certain embodiments, a dummy wellhead may be provided on the seafloor for landing and securing the lower end of the drilling riser while production risers are run. This can help to prevent collisions between the risers.
FIG. 6 contains four views of a transport trolley 32 according to one embodiment of the invention— FIG. 6A is an isometric view, FIG. 6B is a top plan view, FIG. 6D is a side view and FIG. 6C is an end view. Adapter frame lift cylinders 60 are shown within transport trolley 32 . Also shown are openings 62 for guidelines 24 which may be sized to also permit passage of the remote ROV guide post tops (see FIG. 8 ).
FIG. 7 contains four views of an adapter frame 66 according to one embodiment of the invention— FIG. 7A is an isometric view, FIG. 7B is a top plan view, FIG. 7D is a side view and FIG. 7C is an end view. Adapter frame 66 has a central opening 67 with a perimeter rim 74 which may project into opening 67 . Rim (or flange) 74 may be sized and configured to fit drilling riser tensioner system 30 . Drilling riser tensioner system 30 is supported on rim 74 . Load brackets 80 are sized and configured to engage deck support brackets 38 . Lift extensions 78 are sized and configured to engage adapter frame lift cylinders 60 . In a system according to the invention, the static load of the drilling riser assembly is borne on lift extensions 78 when transport trolley 32 is moved horizontally but the static and dynamic loads are borne by load extensions 80 when the drilling riser is connected and tensioned by tensioner system 30 . As shown in FIG. 7 , load extensions 80 may be reinforced with gussets 90 .
Specific design parameters for one particular preferred embodiment of a drilling riser transport system according to the invention are:
The transporter 32 may be supported by four sets of Hillman rollers 54 . The top of the DRT support insert 66 is level with the top of the support rails when the transporter lift cylinders 60 are retracted. The DRT 30 fits within the inner opening 67 of the support insert 66 , and is supported by a ledge 74 around the perimeter of the opening. Lift of the DRT support insert 66 relative to the transporter 32 is sufficient to clear the well head and its associated guide posts. Maximum load carried by the DRT support insert 66 is carried through the brackets 80 . Static load only is carried by the transporter 32 during lift and movement of the drilling riser. The transporter 32 carries no load when the DRT support insert 66 is resting on the brackets 80 . The transporter may be driven by a rack 70 and pinion 68 system powered by hydraulic drive motors 52 .
As shown in the sequence illustrated in FIG. 8 , the transfer method according to the invention begins at Step 1 ( FIG. 8A ) with the drilling riser and its associated tieback connector attached to a home position wellhead. At Step 2 ( FIG. 8B ), the guidelines are slackened so that the ROV can unlock the upper section of the guideposts (“guide post tops”) and move them to the adjacent wellhead. If not already deployed, the guide arms may be folded down (using the ROV) and the guidelines reattached to the drilling riser by positioning the guidelines in the lower guide arms via gates in the guide arms. In Step 3 ( FIG. 8C ), the tieback is disconnected from the home position wellhead and lifted by extending the adapter frame lift cylinders 60 . This provides sufficient clearance to move the tieback connector from the home position wellhead to the adjacent wellhead by applying a selected amount of tension to the guidelines 24 using guide line winches 22 (which may be constant tension winches). The transporter 32 may concurrently move the drilling riser to the closest available drilling position over the target wellhead. The lower guide arms may be free to swivel around the tie back connector to align and connect with the guidelines and guideposts. The guide arms may be sized such that, in the folded position, they may pass through passageways in the drilling riser tensioner and openings 67 in drilling riser transfer trolley 32 . After full positioning tension is applied to the guidelines thereby realigning the tieback connector over the adjacent well (Step 4 ; FIG. 8D ), the drilling riser may be lowered (Step 5 ; FIG. 8E ) by retracting hydraulic lift cylinders 60 , and the tie back connector landed and locked on the adjacent wellhead.
Although particular embodiments of the present invention have been shown and described, they are not intended to limit what this patent covers. One skilled in the art will understand that various changes and modifications may be made without departing from the scope of the present invention as literally and equivalently covered by the following claims. | A floating, offshore drilling and/or production platform is equipped with a rail-mounted transport system that can be positioned at a plurality of selected positions over the well bay of the vessel. The transport system can move a drilling riser with a drilling riser tensioner system and a blowout preventer from one drilling location to another without removing them from the well bay of the vessel. Using the transport system, the drilling riser is lifted just clear of a first well head and positioned over an adjacent, second well head using guidelines. The transport system may then move the upper end of the drilling riser (together with its attached tensioner and BOP) to a second drilling location. A dummy wellhead may be provided on the seafloor in order to secure the lower end of the drilling riser without removing it from the sea while production risers are being installed. | 4 |
The present patent application is a non-provisional application of International Application No. PCT/FR03/00165, filed Jan. 20, 2003.
The invention provides a method of reducing metals or metal alloys of high purity, and in particular metallic chromium.
Certain industries require metals and metal alloys of ever increasing purity. This applies in particular to aviation industries for fabricating the noble parts of turbojets.
In document EP-0 102 892, the Applicant discloses a method of producing metals or alloys comprising the steps consisting in:
a) preparing a metal or a metal alloy in which the non-metallic inclusions are essentially oxides of the base metal;
b) grinding the resulting metal or metal alloy and mixing it with a pelletizing agent and a reducing agent to form pellets; and
c) subjecting the pellets to a vacuum reducing treatment under conditions of pressure and temperature that are controlled so that the reducing agent reacts on the non-metallic inclusions and so that there is no significant sublimation of the metal or of the alloy metals being treated.
That method can involve, in particular, an aluminothermic reaction in step a), said reaction being unbalanced by a shortage of aluminum relative to the quantity needed for a complete reaction. That method enables high purity metallic chromium to be obtained.
Nevertheless, the relative proportion of some impurities can still be too high for some uses of the metal or the alloy. This applies in particular to the contents of atoms of carbon, nitrogen, and oxygen.
An object of the invention is to further improve the purity of the final product.
To this end, the invention provides a method of producing granules of metal in which granules of metal containing non-metallic inclusions and a reducing agent are treated under predetermined conditions of temperature and pressure so that the agent reduces the inclusions, and in which, during the treatment, the granules are disposed in a crucible having an opening and a wall presenting at least one orifice.
The Applicant has found that the presence of one or more orifices in the crucible improves the purity of the final metal or alloy. This applies in particular for atoms of oxygen and carbon for which it has been possible to reduce the relative concentrations on average by 56% and 70% respectively in the samples that the Applicant has analyzed.
Preferably, the crucible is made for the most part out of graphite, or entirely out of graphite.
Here also, the Applicant has found, surprisingly, that contrary to that which might have been expected, the granules are not polluted by the carbon forming the graphite, and that on the contrary such a crucible enables the purity of the product to be increased.
The method of the invention may also present at least one of the following characteristics:
the wall is a side wall; a majority of the orifices occupy a bottom half of the wall; the orifices occupy the bottom two-thirds of the wall; the orifices are disposed in such a manner that more than half the total area defined by the sum of the areas of the orifices occupies the bottom half of the wall; the wall is free from orifices over at least a top-fourth of its height from the opening; the ratio of the total area of the orifice(s) over the total inside volume of the crucible lies in the range 0.5 to 1.5, and preferably in the range 0.80 to 1.20; the or each orifice has an area lying in the range 50 square millimeters (mm 2 ) to 150 mm 2 , and preferably in the range 90 mm 2 to 130 mm 2 ; the orifices are mutually identical; the crucible is of generally constant shape; the crucible is generally circularly symmetrical in shape; the crucible is cylindrical in shape; the treatment is performed under a partial vacuum; during the treatment, the granules are subjected to an air flow; the granules are constituted by a metal such as chromium, titanium, vanadium, molybdenum, manganese, niobium, tungsten, and nickel, or an alloy comprising one of those metals and boron or iron; prior to the treatment, a metallic compound is prepared by means of an aluminothermic reaction between at least one metallic oxide and divided aluminum, and the granules are made from said compound; prior to treatment, the granules are baked; and the method is implemented to produce metallic chromium.
The invention also provides a crucible for producing metallic granules, the crucible possessing an opening and having a wall presenting at least one orifice.
Other characteristics and advantages of the invention appear further from the following description of a preferred implementation given by way of non-limiting example.
BRIEF DESCRIPTION OF THE DRAWING
In the accompanying drawing, the sole FIGURE is an axial vertical section view of a crucible constituting a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The description begins with the crucible of the invention. Thereafter the method in which the crucible is implemented is described.
The crucible 2 comprises a vertical side wall 4 of generally circular cylindrical shape about an axis 6 . The shape of the wall is thus essentially constant along the axis 6 , the wall presenting a section that is circular in a plane perpendicular to the axis. The wall 4 presents an outside face 8 that is accurately cylindrical in shape and an inside face 10 that is slightly frustoconical in shape, tapering a little, with the axis 6 constituting the axis of the cone and with the apex of the cone pointing downwards. The diameter of the inside face 10 thus decreases going downwards.
The wall 4 presents a circular top edge 12 of plane shape defining a top opening 14 of the crucible.
The crucible has a flat bottom 16 closing a bottom axial end of the wall remote from the opening 14 . At the junction between the outside face 8 of the wall 4 and the bottom face 18 of the bottom 16 , the crucible presents a circular shoulder 20 recessed into these two faces and giving the bottom face 18 a diameter that is slightly smaller than that of the opening 14 so as to enable two crucibles to be engaged one in another when they are stacked.
In its top third, the outside face 8 is recessed by a peripheral groove 22 of channel section making the crucible easier to handle with a tool.
The crucible is made of graphite.
The side wall 4 in this example presents a multitude of orifices 24 passing through the thickness of the wall so as to put the inside of the crucible into communication with the outside. Only some of the orifices are shown in FIG. 1 . Specifically, the orifices are disposed in a plurality of circular horizontal rows, each row occupying a plane perpendicular to the axis 6 . In this example, there are 14 such rows. Each row has 20 orifices uniformly distributed around the circumference of the wall. The rows follow one another, being spaced apart by the same distance. The orifices in successive rows are disposed in a staggered configuration, each orifice of a given row forming an isosceles triangle with the nearest two orifices in the row above and/or the row below. The rows follow one another uniformly. They are disposed in such a manner that the orifices occupy the bottom two-thirds of the height of the wall 4 , the top-third adjacent to the opening 14 being completely free from any orifices.
By way of example, the dimensions of the crucible are as follows:
total height, 516 millimeters (mm); height of the crucible from the opening 14 to the inside face of the bottom 16 , 476 mm; total diameter of the crucible, 360 mm; inside diameter of the opening, 313 mm, inside diameter of the bottom, 288 mm; outside diameter of the crucible at the bottom of the groove 22 , 344 mm; the groove 22 is 100 mm from the top edge 12 ; the height of the groove is 60 mm; the highest row of orifices is 20 mm below the groove 22 , measured to the plane passing through the centers of the orifices.
Using identical references for each row, the rows follow one below another at a spacing of 20 mm. The bottom row is thus about 30 mm from the bottom. Given the thickness of the wall 4 , the orifices in this case form ducts, and specifically they have a diameter of 12 mm. The orifices are identical to one another. The area of each orifice is about 113 mm 2 . Since the number of orifices in this case is 280, the total area of the orifices, i.e. the sum of their individual areas, is about 0.0317 square meters (m 2 ). The total inside volume of the crucible is about 0.336 cubic meters (m 3 ). The ratio of the total area of the orifices over the total volume of the crucible is thus about 0.94 in this case.
There follows a description of how the method of the invention is implemented with the above-described crucible in order to produce metallic chromium.
Step a
Chromium oxide (Cr 2 O 3 ), potassium bichromate (K 2 Cr 2 O 7 ) and divided aluminum are introduced into an ordinary crucible. The chromium oxide and the potassium bichromate are present in proportions appropriate for the aluminothermic reaction. The aluminum is present with a shortage relative to the proportion required for complete reaction. This shortage may lie in the range 0.5% to 8%, or indeed 2% to 5% by weight of the stochiometric quantity.
These three ingredients are mixed and then the reaction is initiated. At the end of the reaction, the metal is collected from the bottom of the crucible. The elemental chromium is reduced and the resulting final product is metallic chromium of high purity identical to the aluminothermic chromium that would have been obtained with a complete reaction, except that it contains a very high oxygen content, which oxygen is almost exclusively present in the form of non-metallic inclusions of Cr 2 O 3 (0.40% to 0.80% or even more) together with very few alumina inclusions Al 2 O 3 (100 parts per million (ppm) to 400 ppm, corresponding to 50 ppm to 200 ppm of oxygen bonded with aluminum). Consequently, metallic chromium is obtained with non-metallic inclusions that are constituted mainly by inclusions of Cr 2 O 3 that can easily be eliminated, and to a minor extent by inclusions of alumina that are more difficult to eliminate, but that are present in smaller quantity.
Step b
The chromium from step a) is ground in an impact grinder so as to obtain a fine powder that passes through the screen with a mesh size of 500 micrometers (μm). The grinder bursts these grains, thereby releasing a good fraction of the non-metallic inclusions of Al 2 O 3 and Cr 2 O 3 , with the Cr 2 O 3 inclusions appearing to be released preferentially. This grinding is purifying and produces an air flow. The air flow may also be produced by an auxiliary device such as a blower which contributes to exhausting into ambient air some of the non-metallic inclusions that have been released. A screening step performed at this stage can serve to remove another fraction of the inclusions.
The resulting purified chromium powder is then mixed intimately with a reducing agent and a pelletizing agent. By way of example, the pelletizing agent may be a mixture of Bakelite and an organic binder such as furfuraldehyde. The reducing agent may be constituted by carbon black.
The resulting mixture is formed into pellets or tablets using a conventional compacting press.
After being formed into pellets, the mixture is baked at an appropriate temperature (e.g. 200° C. to 230° C.).
Step c
The resulting pellets 26 are then placed in the crucible 2 and subjected to reducing treatment at 1100° C. to 1400° C. under a vacuum of about 133×10 −4 pascals (Pa) The crucible is filled with pellets up to its opening.
At the beginning of the vacuum heating cycle, the Bakelite decomposes at a certain temperature, leaving a carbon skeleton which adds to the carbon black that was introduced into the mixture as a reducing agent. Once the treatment temperature has been reached, this carbon reacts with the oxygen of the Cr 2 O 3 that remains in the material, but reacts hardly at all with the oxygen of the alumina Al 2 O 3 .
The vacuum in the treatment furnace is brought to 133×10 −1 Pa by controlled sweeping with a non-oxidizing gas or a reducing gas such as hydrogen. To terminate, the product is allowed to cool under an inert atmosphere.
The presence of the orifices appears to have a great influence on the contents of certain impurities, and in particular of oxygen and carbon atoms. The Applicant has undertaken experiments, treating pellets having the same composition in crucibles that are not pierced and in crucibles that are pierced. The contents of atoms of oxygen, of nitrogen, and of carbon were analyzed in the final products, and these contents are summarized in the table below:
O 2
C
N
Non-pierced (ppm)
852
450
31
Pierced (ppm)
376
135
24
Difference (%)
−56
−70
−22
The impurity contents are given in parts per million (ppm) while the difference is given as a percentage. It can be seen that the presence of orifices enables the content of oxygen atoms to be reduced by about 56% and the content of carbon atoms by about 70%.
It is probable that the presence of the orifices facilitates gas flow through the crucible during treatment, the orifices co-operating with the opening 14 to cause the gas to flow over the full height of the crucible.
It is preferable to provide no orifices in the top portion of the crucible in order to avoid weakening the crucible.
Naturally, numerous modifications can be applied to the invention without going beyond the ambit of the invention.
The crucible presenting orifices may be made out of a material other than graphite. A graphite crucible could be provided that does not have any orifices other than the opening.
The orifices need not be disposed uniformly in the wall. The orifices could be of differing sizes.
Similarly, step a) could be undertaken other than by aluminothermically, for example silicothermically or by reducing in an electric furnace, in order to obtain a metal or a an alloy having non-metallic inclusions in the form of oxides of the base metal. | In the method of producing metals or metal alloys of high purity, in particular metallic chromium, granules of metal containing non-metallic inclusions and a reducing agent are treated under predetermined conditions of temperature and pressure so that the reducing agent reacts on the inclusions. During the treatment, the granules ( 26 ) are placed in a crucible ( 2 ) having an opening ( 14 ), and a wall ( 4 ) presenting at least one orifice ( 24 ). | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119(e)(1) to U.S. Ser. No. 60/973,202, filed Sep. 18, 2007, and under 35 U.S.C. §119 to German patent application 10 2007 044 678.2, filed Sep. 18, 2007. The entire contents of these applications are incorporated herein by reference.
FIELD
The disclosure relates to a microlithographic projection exposure apparatus and a microlithographic projection exposure apparatus, as well as related components, methods and articles made by the methods.
BACKGROUND
Microlithography is used for the production of microstructured components, such as, for example, integrated circuits or LCDs. In general, the microlithography process is carried out in what is referred to as a projection exposure apparatus having an illumination system and a projection objective. Generally, the mask (commonly referred to as a reticle) is illuminated by the illumination system, and the image of the mask is projected by the projection objective onto a substrate (for example a silicon wafer). Typically, the substrate is coated with a light-sensitive layer (for example photoresist) which is arranged in the image plane of the projection objective so that the mask structure is transferred onto the light-sensitive coating on the substrate, generally reduced by a factor of 0.25.
SUMMARY
In some embodiments, the disclosure provides a microlithographic projection exposure apparatus and a method of its operation that can provide improved compensation of aberrations caused by mask structures.
In certain embodiments, the disclosure provides a method of operating a microlithographic projection exposure apparatus. The apparatus has an illumination system and a projection objective. The illumination system illuminates a mask arranged in an object plane of the projection objective. The mask has structures which that are to be imaged. The method includes illuminating a pupil plane of the illumination system with light. The method also includes modifying, in a plane of the projection objective, the phase, amplitude and/or polarization of the light passing through that plane. Modification is effected for at least two diffraction orders in mutually different ways, whereby a mask-induced loss in image contrast obtained in the imaging of the structures is reduced compared to a method without the modification.
The method can involve separating from each other diffraction orders which are generated by points in mirror image symmetry relative to each other in the pupil plane of the illumination system.
It is possible to set in the illumination system an illumination setting (a given intensity distribution in the pupil plane of the illumination system) which is in point symmetry relationship with respect to the pupil center, but not in mirror image symmetry relationship with respect to a plane of symmetry of the structure which is to be imaged. In accordance with its definition, the edge of the pupil is defined by rays which are incident on the field plane (reticle plane) in the optical system or the illumination system at the maximum aperture angle. That can provide that different diffraction orders (in particular the zero and the first diffraction orders) which are generated by the light emanating from points which are in mirror image symmetrical relationship with each other in the pupil plane of the illumination system come to lie at different locations in a pupil plane of the projection objective. Consequently those diffraction orders can be modified separately or independently of each other, by for example using an optical filter which, by way of its optically effective surface, has regions that can have different influence on phase and/or amplitude for at least one polarization direction.
In some embodiments, the modifying is carried out in such a way that for a first illumination direction a first interference image is obtained and for a second illumination direction a second interference image is obtained, where a lateral offset between the first interference image and the second interference images is reduced. In certain embodiments, the lateral offset is reduced to a value of not more than 5% (e.g., not more than 2.5%) of a period of the first or second interference image. In some embodiments, the lateral offset is reduced at least by a factor of 2 (e.g., at least by a factor of 3, at least by a factor of 4).
The change or difference in the diffraction phase, if the half grating period (or half pitch) is reduced down to approximately 100 nm, may, for example, correspond to approximately 11% of the period of the structure. This is because the change or difference in the diffraction phase directly appears as lateral offset between the respective interference images for two different illumination directions. In practice, such lateral offsets in the range of approximately 10% can begin to have negative effects on the result of the lithographic process or the technical application, respectively. In certain embodiments, this lateral offset is reduced to not more than 5% (e.g., not more than 2.5%) of the period of the structure.
In some embodiments, monopoles of the set illumination setting are arranged in mirror image symmetrical relationship with each other in the pupil plane of the illumination system and illuminate the mask at different moments in time (e.g., only at different moments in time) with a time difference or a time interval ΔT therebetween. Then, in the exposure process, an altered phase, amplitude or polarization modification is produced after expiry of the time interval ΔT, in the projection objective. That can be achieved via an optical filter by either replacing the optical filter or by adjusting the optical filter with respect to the arrangement of its region or regions which modify the phase and/or amplitude.
The disclosure is not limited to replacing or adjusting an optical filter. For example, in some embodiments, the modification of phase, amplitude and/or phase shift, which is achieved after expiry of the time interval ΔT (or at the moment of illumination of the respective other illumination pole of the set illumination setting) in the projection objective can also be implemented via a lens decentering procedure, a lens displacement along the optical axis of the projection objective, a lens tilting movement, a lens bending effect or by the manipulation of a mirror surface in the projection objective. Local thermal changes in lenses due for example to IR radiation can also be used for a modification to the phase.
In some embodiments, an optical filter is used, which over its optically effective surface has regions involving differing phase shift and/or amplitude influencing for at least one polarization direction. A change in polarization can be achieved, in the event of phase and/or amplitude being influenced in different ways, for various polarization directions. If the phase and/or amplitude for different polarization directions are influenced in the same manner in contrast that affords a purely scalar change in transmission or change in phase without a change in polarization.
In certain embodiments, the structures of the mask have at least one repetition direction. In such embodiments, illuminating the pupil plane of the illumination system can be effected with an intensity distribution which has two illumination poles.
In some embodiments, a connecting straight line between the centroids of the illumination poles are neither perpendicular nor parallel to the repetition direction.
In certain embodiments, an angle between the centroids of the illumination poles and the repetition direction is less than 45° (e.g., less than 35°, less than 25°, less than 15°).
In some embodiments, in a pupil plane of the projection objective the first diffraction order of one illumination pole is located at least in close neighborhood to the zero diffraction order of the other illumination pole, and vice versa.
In certain embodiments, a characteristic width (which may in particular be a half grating period also called half pitch, wherein pitch denotes the period of the grid) of the structures on the mask to be imaged, is not more than two times of the wavelength (e.g., not more than 1.4 times of the wavelength, not more than 1.2 times of the wavelength, not more than the wavelength) of the light used in the microlithography process.
In some embodiments, the characteristic width of the structures on the mask to be imaged is not more than 300 nm (e.g., not more than 250 nm, not more than 200 nm). For a typical imaging scale of ¼, a half-pitch of, for example, 180 nm corresponds to a typical structure width of 45 nm on the wafer. In such situations, the concept of the disclosure can be particularly effective because the influence of aberrations introduced by the mask can become particularly noticeable with decreasing grating period, such as when the structures on the mask to be imaged comes in the proximity of the wavelength of the light used in the microlithography process.
In some embodiments, the disclosure provides a method of operating a microlithographic projection exposure apparatus. The apparatus includes an illumination system and a projection objective. The illumination system illuminates a mask arranged in an object plane of the projection objective. The mask has structures which are to be imaged. The method includes illuminating a pupil plane of the illumination system with light. The method also includes modifying, in a plane of the projection objective, the polarization of the light passing through that plane. The modification is effected for at least two diffraction orders in mutually different ways.
In certain embodiments, the disclosure provides an optical system of a projection objective of a microlithographic projection exposure apparatus. The optical system includes an optical filter configured to manipulate light passing through the optical filter. The positional dependency of the manipulation caused by that optical filter can be described by the equation:
M ( x, y )= M (− x, −y )
where x and y denote positional co-ordinates in a plane of the projection objective, and wherein M is a parameter characteristic of the light passing through the optical filter. The parameter characteristic of the light passing through the optical filter can be the amplitude, phase or polarization of that light.
The disclosure relates to a microlithographic projection exposure apparatus, a process for the microlithographic production of microstructured components, and a microstructured component.
Further configurations of the disclosure are set forth in the description, claims and figures. The disclosure is described in greater detail hereinafter by means of embodiments by way of example illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIGS. 1 a - c show diagrammatic views to explain the effect of mask aberrations on the microlithography process,
FIGS. 2 a - b show diagrams by way of example illustrating calculated dependencies in respect of diffraction efficiency ( FIG. 2 a ) and diffraction phase (FIG. 2 b ) on half the grating period in the structure of a mask for different diffraction orders and different polarization states,
FIGS. 3 a - c show diagrammatic views to illustrate a method,
FIG. 4 shows a diagrammatic view of an optical filter,
FIG. 5 a - d show diagrammatic views to illustrate a method, and
FIG. 6 shows a diagrammatic view illustrating the structure in principle of a microlithographic projection exposure apparatus.
DETAILED DESCRIPTION
If the width of the structures on the mask is in the proximity of the wavelength of the light used in the microlithography process, the mask can introduce aberrations because the diffraction orders can experience a phase and amplitude change, the magnitude of which depends on the period of the mask structures.
FIG. 1 a illustrates a situation in which light is incident on a mask 100 at two different directions of incidence identified by “A” and “B” respectively. Mask 100 has structures 102 (for example of chromium, Cr), arranged on a mask substrate 101 (for example of quartz glass, SiO 2 ). Diffraction orders occurring as a consequence of diffraction at the structures 102 downstream of the mask 100 are denoted for the light from the direction of incidence A by A- 0 (=zero diffraction order) and A- 1 (=first diffraction order), and for the light from the direction of incidence B by B- 0 (=zero diffraction order) and B- 1 (=first diffraction order). FIG. 1 b shows the intensity variation in dependence on the positional coordinate x for the partial images respectively produced with the light from the different directions of incidence A and B. FIG. 1 c shows the intensity variation obtained by summing of those two partial images. The total image afforded by addition of the two partial images as shown in FIG. 1 c is of a contrast which is reduced in comparison with the individual partial images.
For a first different illumination direction A, an interference is obtained between the first diffraction order A- 1 with the zero diffraction order A- 0 , which produces a first interference image which is labeled with “A” in FIG. 1 b . For a second illumination direction B, an interference is obtained between the first diffraction order B- 1 with the zero diffraction order B- 0 , which produces a second interference image which is labeled with “B” in FIG. 1 b . The first and second interference images or partial images, respectively, are laterally displaced with respect to each other, i.e. have a lateral offset Δx, which can be seen in FIG. 1 b by comparison between the solid and dashed line. The lateral offset Δx corresponds to a fading or decreased contrast, as can be seen in FIG. 1 c, which can have negative effects.
FIGS. 2 a and 2 b show, for the example of a binary chromium-quartz glass mask, the calculated dependency with respect to diffraction efficiency (in percent, FIG. 2 a ) and diffraction phase (in degrees, FIG. 2 b ) on half the grating period (in nm), in each case both for the zero diffraction order and the first diffraction order as well as for two mutually orthogonal polarization states (TE and TM). The calculation was implemented by what is referred to as the RCWA theory. From the configuration of the respective curves in FIGS. 2 a and 2 b , it is apparent the effects of aberrations introduced by the mask become only comparatively slightly noticeable at a value of half the grating period of about 500 nm (corresponding to a grating period of 1 μm) as the curves represent approximately horizontal straight lines and also the degree of deviation of the curves for respectively orthogonal polarization states is slight. With a decreasing grating period the respective curves differ markedly from a straight-line configuration, while in addition there are marked differences for mutually orthogonal polarization states.
Referring to FIG. 2 b , the change or difference in the diffraction phase, if the half grating period (or half pitch) is reduced down to approximately 100 nm, has a value of roughly 40°. This value appears as lateral offset between the respective interference images for two different illumination directions and corresponds to approximately 11% of the period. It can therefore be desirable to reduce this lateral offset and the accompanying loss in image contrast.
FIGS. 3 a - c describe a method carried out in a microlithographic projection exposure apparatus for which a structure by way of example is described hereinafter with reference to FIG. 6 .
FIG. 3 a diagrammatically shows an intensity distribution 310 which is set in a pupil plane of the illumination system (by using one or more suitable pupil-forming elements, for example diffractive optical elements). FIG. 3 b is a view in greatly simplified fashion of a structure 320 by way of example, as can be provided on a mask arranged in the object plane of the projection objective. FIG. 3 c is also a diagrammatic view showing the arrangement of the zero and first diffraction orders obtained in a pupil plane of the projection objective by virtue of diffraction at the mask structure 320 .
The intensity distribution in the pupil plane of the illumination system, that is to say what is referred to as the illumination setting, includes as shown in FIG. 3 a precisely two illumination poles which are denoted by “A” and “B” respectively and which in the pupil plane extend in point symmetrical relationship with a point on the optical axis of the illumination system, but which are not in mutually mirror image symmetrical relationship, with respect to an axis of symmetry of the structure whose image is to be formed. In other words, a connecting line joining the two illumination poles “A” and “B” does not extend perpendicularly to the structure direction (extending in the x-direction as shown in FIG. 3 b ) of the mask structure 320 .
As can be seen from FIG. 3 c the consequence of that choice of the illumination setting is that the different diffraction orders (in particular the zero and first diffraction orders) which are produced as a consequence of diffraction of the light of the two illumination poles in the pupil plane of the projection objective come to lie at mutually different positions in the pupil plane of the projection objective. The region involving the zero diffraction order for the diffraction pole A in FIG. 3 a is identified by “A- 0 ”, the region of the first diffraction order for the diffraction pole A is identified by “A- 1 ”,the region of the zero diffraction order for the illumination pole B is denoted by “B- 0 ” and the region of the first diffraction order for the illumination pole B is denoted by “B- 1 ”.
The regions “A- 0 ”, “A- 1 ”, “B- 0 ” and “B- 1 ” can be influenced in different ways from each other to at least partially compensate for mask aberrations. The influencing effect can be implemented with respect to the phase and/or amplitude for at least one polarization direction.
FIG. 4 shows an example an optical filter 400 which is suitable for that purpose and which is made up of portions 410 - 440 which in the example are in the form of segments of a circle, in which case the portions 410 and 420 have transmission and/or phase shift properties which are different from the transmission and phase shift properties respectively of the regions 430 and 440 . In filter 400 the phase shift properties of the regions 410 and 420 (and the regions 430 and 440 respectively) are respectively mutually coincident.
FIG. 5 a and FIG. 5 c show illumination poles 511 and 521 which are produced in a pupil plane of the illumination system in such a way that they are arranged both in point symmetrical relationship with a point on the optical axis of the illumination system and also in mutually mirror image symmetrical relationship with respect to a plane intersecting that optical axis or with respect to an axis of symmetry of the structure, the image of which is to be produced.
Illumination of illumination poles 511 and 521 occurs not at the same time but at different moments in time or at different field points in the scanning operation. At the different moments in time, the phase, amplitude and/or polarization are manipulated differently in the projection objective. As an example, an optical filter can be used in the projection objective for this purpose. In such embodiments, in the time interval between the two moments in time, the optical filter can either be replaced or can be adjusted with respect to the arrangement of its regions that manipulate amplitude, phase or polarization. FIG. 5 b shows an example in which an optical filter 530 is used in the projection objective during exposure with the illumination setting of FIG. 5 a . FIG. 5 d shows an example where an optical filter 540 is used during exposure with the illumination setting of FIG. 5 c . Optical filters 530 and 540 differ from each other with respect to the transmission and/or phase shift they produce.
In some embodiments, time-displaced exposure with different illumination settings can be implemented as follows. The wafer is exposed using a first illumination setting. There is then a change in the illumination setting and an optical filter, and the wafer is exposed using a second illumination setting. Typical change rates can be in the seconds range. If a through-put rate of, for example, 120 wafers per hour with single exposure is assumed to apply, a change in the optical filter can take place in terms of order of magnitude, for example, every 30 seconds.
WO 2006/097135 A1 discloses arrangements for and methods of rapidly changing illumination settings. Similar methods can be used for a rapid change of an optical filter, for example in a pupil plane of the projection objective. US No 2007/0153247 A1 or US No 2005/0213070 A1 disclose systems in which the scanner slot can be divided into two regions so as to make different pupil regions or planes manipulatable separately. Such systems can be implemented in the system described herein.
FIG. 6 is a purely diagrammatic view showing a structure in principle and by way of example of a microlithographic projection exposure apparatus. The microlithographic projection exposure apparatus has an illumination system 601 and a projection objective 602 . The illumination system 601 serves for illuminating a structure-bearing mask (reticle) 603 with light from a light source unit 604 which for example includes an ArF laser for a working wavelength of 193 nm as well as a beam shaping optical mechanism for producing a parallel light beam. The parallel light beam of the light source unit 604 is firstly incident on a diffractive optical element 605 which, by way of an angle radiation characteristic defined by the respective diffractive surface structure, produces in a pupil plane P 1 a desired intensity distribution (for example dipole or quadrupole distribution). Disposed downstream of the diffractive optical element 605 in the light propagation direction is an optical unit 606 including a zoom objective for producing a parallel light beam of variable diameter, and an axicon lens. Different illumination configurations are produced by the zoom objective in conjunction with the upstream-disposed diffractive optical element 605 in the pupil plane P 1 depending on the respective zoom position and the position of the axicon elements. In the illustrated embodiment the optical unit 606 further includes a deflection mirror 607 . Disposed downstream of the pupil plane P 1 in the light propagation direction in the beam path is a light mixing device 608 which for example in per se known manner can have an arrangement of microoptical elements that is suitable for achieving a light mixing effect. The light mixing device 608 is followed in the light propagation direction by a lens group 609 , downstream of which is disposed a field plane F 1 with a reticle masking system (REMA) which is projected by an REMA objective 610 following in the light propagation direction onto the structure-bearing mask (reticle) 603 arranged in the field plane F 2 and thereby limits the illuminated region on the reticle. The image of the structure-bearing mask 603 is formed with the projection objective 602 which in the illustrated embodiment has two pupil planes PP 1 and PP 2 , on a substrate 611 or a wafer provided with a light-sensitive layer.
While certain embodiments have been described, it will be appreciated by one skilled in the art that variations and alternatives are possible. | The disclosure relates to a microlithographic projection exposure apparatus and a microlithographic projection exposure apparatus, as well as related components, methods and articles made by the methods. The microlithographic projection exposure apparatus includes an illumination system and a projection objective. The illumination system can illuminate a mask arranged in an object plane of the projection objective. The mask can have structures which are to be imaged. The method can include illuminating a pupil plane of the illumination system with light. The method can also include modifying, in a plane of the projection objective, the phase, amplitude and/or polarization of the light passing through that plane. The modification can be effected for at least two diffraction orders in mutually different ways. A mask-induced loss in image contrast obtained in the imaging of the structures can be reduced compared to a method without the modification. | 6 |
This is a continuation-in-part of U.S. Pat. No. 8,375,860 filed on May 4, 2011 and which is incorporated by reference herein.
DEDICATORY CLAUSE
The invention described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes without payment of any royalties thereon.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to flechettes or dart-like projectiles.
2. Discussion of the Background
Conventional flechettes in the 60 grain to 150 grain weight class have been used successfully in weapons but suffer from two drawbacks. The first drawback is that their flight characteristics are suboptimal. High speed film of their flight shows that most of the flechettes dispensed from a warhead pitch and yaw significantly during their flight.
It is understood that the pitch and yaw behavior, which slows the flechettes and reduces their lethality, is due to a combination of transverse angular rates induced at dispense, aerodynamic or physical interactions between flechettes in the dispensed population, and manufacturing imperfections in the flechettes themselves.
As a result of these effects, flechette patterns are typically extremely elongated along the axis tangent to the flight path, with a significant time lag between the arrival at the target of the first flechettes, (which have the highest velocity and are the most lethal), and the last arriving, slower flechettes (which are the least lethal). The elongated patterns indicate that conventional flechettes lose significant portions of their velocity and lethality attempting to recover a nose-first orientation after experiencing high transverse angular rate perturbations.
The second drawback with the conventional flechette design is that packing constraints limit the size of the flechette tailfins to a size smaller than would be ideal to optimize their flight stability. (Flechettes having four tailfins are the conventional design). If the tailfins are made larger for better flight performance, the flechettes do not pack well. If they are made smaller for better packaging, the flechettes lose even more terminal performance due to increased angular rate oscillations.
SUMMARY OF THE INVENTION
The flechette of the present invention has its concentration of mass centered in a forward section for stability with a center of pressure being located proximate to the root of the tail. In the tail section of the flechette, two tailfins are arranged in a flattened out “Z” or S-shaped formation when viewed from the aft end of the flechette. The flechette of the present invention is designed to allow for effective stacking while maintaining effective flight performance.
The flechette body is rectangular with an aspect ratio chosen so that the packing density is maximized, and the tailfins are rotated to an angle relative to the rectangular flechette body so that the tailfins of adjacent flechettes do not interfere with each other. Additionally, the tailfins of the flechette are angled to improve flight characteristics by inducing a spin to the flechette as it flies through the air. The wide separation between the center of gravity of the flechette and its center of pressure ensures that the flechette recovers quickly from any pitch or yaw angle (up to being completely reversed). Inducing a rolling moment to the flechette allows the perturbations caused by manufacturing imperfections to be integrated out of the flight path while the flechette is in flight.
The flechette of the present invention experiences low drag while achieving uniform and stable flight characteristics. When multiple flechettes of the present invention are stacked into a packaged unit, each flechette of the packaged unit, upon being dispensed, will achieve similar flight characteristics so as to arrive at a target with greater uniformity and accuracy.
The flechette of the present invention is made by a two-part construction, with a two-fin spinning airframe and is manufactured by sheet metal or equivalent by folding and bending operations.
When multiple flechettes are stacked, the forebodies of the flechettes stack in parallel and in contact, in rows and columns. The parallel stacking is both on the top and bottom surfaces and on the sides. The canted two tailfins nest without interference when stacked in rows and columns. The flechette has a generally rectangular forebody, with curved sides, that is self clocking for stacking purposes.
DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained by reference to the following detailed description when considered in connection with the accompanying drawings.
FIG. 1 is a perspective drawing of the flechette of the present invention.
FIG. 2 is a top or bottom view of the flechette of the present invention.
FIG. 3 is an aft view of the two tailfins of the present invention which demonstrates a relatively flat, generally “Z” or S-shaped arrangement of the tailfins.
FIG. 4 is an exploded view of the tip and quill of the present invention prior to assembly.
FIG. 5 is frontal perspective view of an assembled flechette of the present invention.
FIG. 6 is a perspective view of packaged flechettes of the present invention which are stacked in rows and columns.
FIG. 7 is a perspective view of packaged flechettes of the present invention which are stacked in a radial arrangement.
FIG. 8 is a side, sectional view of a warhead in which flechettes of the present invention are stacked into discrete packages or pucks without interleaving.
FIG. 9 is a side view of a typical prior art flechette which illustrates the location of its center of gravity relative to its center of pressure.
FIG. 10 is a side view of a flechette according to the present invention which illustrates the location of its center of gravity relative to its center of pressure.
FIG. 11 is a cut-away, perspective view of stacked flechettes according to the present invention stacked within a shotgun shell.
FIG. 12 is a perspective view illustrating flechettes of the present invention as they would appear exiting the barrel after having been fired from a shotgun.
FIG. 13 is an aft view of the two tail fins of the flechette of the present invention demonstrating that the end aft radial edges or points on the undersides of the two tail fins are approximately 180 degrees apart.
FIG. 14 is a side-view of the flechette of the present invention with axis provided for relational location appreciation of the various points and parts of the flechette.
DETAILED DESCRIPTION
With reference to FIG. 1 , the flechette 10 of the present invention has a forward body 20 which has a substantially rectangular box-like shape, with the forward body 20 having a front tip or nose 22 . The forward body 20 is connected to a tail section 24 with the tail section 24 having two integrally connected tailfins or fins 24 A, 24 B located at the aft of the flechette 10 . Both fins 24 A, 24 B are arranged so as to form a compound angularity which is represented by a longitudinal angle θ and a radial angle Φ ( FIGS. 2 and 3 ).
In FIG. 2 , angle θ is understood as being that angle formed by dotted lines AA and BB. Line AA represents the bend axis where the tailfin 24 A adjoins the flat portion of the tail section 24 and line BB represents the longitudinal center line of the flechette 10 . In a flight-tested prototype of the present invention, the angle θ measured 4.5 degrees.
With reference to FIG. 3 , a radial angle Φ is formed by axis line CC and line DD. Line DD is colinear with the underside edge of fin 24 A. Line EE is normal to line CC. Lines DD and EE form angle α. As FIG. 3 further demonstrates, fins 24 A and 24 B have a Z-shaped or S-shaped orientation. As is portrayed by arrow 18 of FIG. 3 , the shape and angular orientation of fins 24 A and 24 B cause flechette 10 to spin or rotate in flight.
In a successfully tested prototype of the present invention, the angle θ measured 4.5 degrees, the radial angle Φ measured 57 degrees and angle α formed by lines EE and DD measured 33 degrees. Also, in the successfully tested prototype of the present invention, the total length of the flechette measured approximately two inches long. The tail section was approximately 0.5 inches long, with the forward body being about 1.5 inches long. The forward body was approximately 0.2 inches wide and 0.1 inches thick. The width of the tail section at its widest point was approximately 0.4 inches. The teachings of the present invention can be utilized in a flechette of other dimensions and angularities; thus the given dimensions of the successfully tested prototype are in no way to be considered limiting as to the invention claimed.
To further appreciate the angular relationship of tailfins 24 A and 24 B, in the successfully tested prototype of the present invention an extreme aft point M located on the topside of tail fin 24 A and an extreme aft point N located on the underside of tail fin 24 B were located approximately 180 degrees apart (see FIG. 13 ). As such, in the prototype tested, the extreme aft point M and extreme aft point N could be thought as being in a substantially half-circle orientation to one another.
In FIG. 4 , a flechette 10 of the present invention includes forward section 20 F having sides 25 A, 25 B which define and are integrally connected to a bottom or trough 29 of the forward section 20 F. A quill section 30 , is integrally connected to tail section 24 , and extends from tip 35 to the roots 35 A, 35 B of tail section 24 .
Quill section 30 slides into the trough 29 of the forward section 29 F until the front tip 35 of the quill section 30 is located at the nose 22 of the forward section 20 F. Serrated barbs, such as barbs 32 A, 32 B, 32 C are positioned on the sides of the quill section 30 so as to secure contact with the sides 25 A, 25 B of forward section 20 F upon assembly.
Upon insertion into the trough 29 of the front section 20 F, the tip 35 of quill section comes to rest at the nose 22 of the forward section 29 F. When press-fit and stamped during the assembly process, the quill section 30 and the front section 20 F become forward body 20 .
The flechette 10 of the present invention can be made of carbon steel sheet or strip or virtually any appropriate material. It is not required that the quill section 30 and the front section 20 F be made from the same material.
The nose of the flechette is tapered as is the rear 28 of the forward body 20 . This tapering can be done before or after the assembly process. The nose 22 can be further machined to give a desired shape, such as a sharp or pointed nose, but the tapered nose shown in FIGS. 2 and 5 has performed well in tests.
Once the flechette 10 of the present invention is manufactured and assembled, the flechette becomes a one-piece aerodynamic body of symmetrical shape. (Thus, the terms top or bottom can be used interchangeably in respect to flechette 10 ). The quill section 30 can be cut from steel or aluminum sheet or strips with a material composition and thickness suitable to common sheet metal for manufacturing and forming processes. The front section 20 F can be made from similar or higher density materials to that of quill section 30 and can be formed from metal tubing, metal sheet, strip material or other suitable material.
FIG. 6 demonstrates the stacking capability of the flechette of the present invention, where a stacked rectangular array of flechettes 100 according to the present invention has three columns and four rows of flechettes with flechettes 10 A, 10 B and 10 C forming one row of flechettes and flechettes 10 C, 10 D, 10 E and 10 F form one column of flechettes. Dotted circle 75 highlights how the “Z” or S-shaped fins of the flechettes of the present invention allow effective stacking without detrimental interference between the flechettes.
In FIG. 7 , a radially stacked arrangement or puck 40 of flechettes according to the present invention is shown which demonstrates four radially oriented rows or circles of flechettes. Dotted circle 759 highlights that the “Z” or S-shaped fins of the flechette 10 of the present invention allow multiple flechettes of the present invention to be radially packaged without interference between adjacent flechettes within the same radially row and without interference between the flechettes in adjacent radial rows.
In FIG. 8 , a warhead 55 , such as, for example, the warhead of a Hydra 70 rocket, is provided with a hollow cylindrical casing in which discrete pucks of flechettes are stacked unlike the prior art where the flechettes are longitudinally interleaved to achieve the necessary packing density. Pucks 40 A, 40 B, etc., of flechettes according to the present invention are stacked within the casing in the orientation demonstrated in FIG. 7 .
The discrete packaging arrangement is shown as the areas 45 A, 45 B, 45 C, etc., where the tails of the flechettes in the preceding puck are in contact with the nose of the flechettes in the subsequent puck. A pusher charge 47 burns to shear the warhead nose off thereby expelling the flechettes out of the front of the casing.
In FIG. 9 , the center of gravity C g and the center of pressure C p of a typical, conventional, prior art flechette 66 is shown.
In FIG. 10 , a side view of the flechette 10 according to the present invention demonstrates the location of the center of gravity Cg′ and the center of pressure Cp′ on the flechette of the present invention. One will notice that the center of gravity is further forward and the center of pressure is further backward than in the typical prior art flechette which indicates greater aerodynamic stability.
In FIG. 11 , a shotgun shell 60 according to the present invention has a stacked configuration of flechettes 109 arranged within the shell. As an alternative to the arrangement of FIG. 12 , the flechettes of the present invention could be arranged in a radial orientation so as to be radially stacked within the shotgun shell's wadding.
FIG. 12 shows a stacked configuration of flechettes 109 as they would appear after being fired from a shotgun as the conformal plastic sabots 61 housing the flechettes in the shotgun shell are aerodynamically discarded upon exiting the gun's barrel.
With reference to FIG. 14 , the flechette 10 of the present invention has a most forward point F and a most rear point R. The line KK is the horizontal axis of flechette 10 and extends through the center of gravity Cg′ of flechette 10 . Line GG extends through the center of gravity Cg′ with line GG intersecting and being normal to line KK. Line PP extends through the center of pressure Cp′ with line PP intersecting and being normal to line KK. Line MM extends through the most forward point F and line NN extends through most rear point R. Lines MM, GG, PP and NN are parallel to each other. Line LL is parallel to line KK. The distance from point A to point B on line LL is equal to the distance between the most forward point F and the center of gravity Cg′. The distance from point A to point C on line LL is equal to the distance between the most forward point F and the center of pressure Cp′. The distance from point F to point R is equal to the distance between point A and point D on line LL.
Still with reference to FIG. 14 , in the present invention, the center of gravity is designed to be closer to point F than to point R, i.e., the center of gravity is located in the front portion of the flechette at a location which is less than half the length of the flechette as measured from point F. In other words line segment AB divided by line segment AD is less than 50%. In a protoype of the present invention, AB/AD was equal to 45.8%. Ideally the center of gravity Cg′ should be as close to the front of the flechette, i.e., as close to forward point F as possible.
The radial distance of line LL from the horizontal axis KK is a further radial distance than from the horizontal axis than is the radial distance from the horizontal axis to any point on the flechette. Line LL is normal to line NN and Line LL is normal to line MM. Accordingly in that line MM intersects line LL at point A and line NN intersects point D on line LL, the distance from line segment AD on line LL is equal to the distance between the most forward point F and most rear point R.
The pragmatic features of the present invention include the fact that when the pucks 40 of flechettes are stacked within a warhead such stacking can be done without the increased cost and complexity and without the longitudinal interleaving of flechettes which occurs in the prior art. Further, the flechettes of the present invention remove the need to turn the flechettes to a particular clocking angle (to improve packing density) as is done in the prior art.
The rectangular cross section of the flechettes (see, FIG. 13 ) of the present invention ensures the flechettes have consistent clocking orientations and that the radial angle of the fins 24 A, 24 B is oriented at an angle that allows adjacent fins to nest without interference.
The transition from dispense to stable flight is a critical event in the flight of a flechette. When a shotgun shell containing the flechettes according to the present invention is fired or when the flechettes of the present invention are dispensed from a warhead, the flechettes are ejected with high translational velocity, moderate roll rate and moderate to high transverse angular pitch and yaw rates and attitudes into the air.
The location of the center of gravity of the flechette 10 of the present invention when combined with the relatively large tailfin region and its angled “Z” or S-shaped oriented, rotation-inducing fins 24 A, 24 B ensure optimal performance. Upon dispense, the flechettes of the present invention quickly weathervane into a nose-first flight orientation even when the fins are aerodynamically stalled due to high angles of attack.
As the flechettes of the present invention assume a nose-first orientation they begin to spin around the longitudinal axis as demonstrated by arrow 18 in FIG. 3 . This spinning is accomplished by the offset separation and small incidence angle θ ( FIG. 2 ) of the fins 24 A, 24 B ( FIG. 4 ). The spinning serves the purpose of further enhancing the aerodynamic stability of the flechettes and mitigating the negative effects of high volume production tolerances and misalignments on their flight path.
As a result of the improved aerodynamic properties of the flechette of the present invention, the dispensed flechettes are able to arrive at a target area with greater accuracy and at higher and more consistent velocity. Thus, the size and number of gaps in the dispersion pattern of the flechettes is reduced and target effects are improved.
The flechette of the present invention combines simple and inexpensive manufacturing techniques with improvements in flight performance and packaging. The result is that manufacturing costs of the present invention are competitive with prior art designs; however, the effectiveness of the flechettes is much improved compared to the prior art.
Since the flechettes of the present invention are designed to be self-correcting and self-orienting, an acceptable packing density can be achieved in a warhead or shotgun shell without undue effort and expense.
After the flechettes of the present invention are released from their packaging, their forward placed center of gravity and fin dimensions and orientations ensure that the flechettes are quickly directed toward their intended flight path.
For flechettes which are dispensed from a shotgun shell, the velocity improvements translate into increased range while increasing accuracy.
The flechettes of the present invention allow for rectangular stacking with virtually any number of desired rows or columns of flechettes and allow for radial stacking with virtually any number of radial rows.
Various modifications are possible without deviating from the spirit of the present invention. Accordingly the scope of the invention is limited only by the claim language which follows hereafter. | A flechette has a forward body ( 20 ) containing its center of gravity which is connected to a tail section ( 24 ). The tail section has a pair of fins ( 24 A, 24 B) each having a preselected longitudinal angle and radial angle. When the two fins are viewed from the aft of the flechette, the pair of fins demonstrate a S-shaped orientation. The size, shape and orientation of the pair of fins provide aerodynamic stability to the flechette while allowing the flechette to be stacked with like-shaped flechettes. The two-piece assembly of the flechette easily accommodates the use of different density materials for the respective pieces. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is in the field of pyrometallurgical furnaces, particularly for melting ore concentrates and for the aftertreatment of the melts, and is concerned with a sectionalized system of furnace walls in which the individual sections are readily removable for replacement.
2. Description of the prior Art
In previously described pyrometallurgical furnace systems such as those for melting fine-grained, sulfidic lead ore concentrates, and shown in German OS No. 29 35 394, FIGS. 4 and 5, the furnace walls in the area which comes into contact with the molten materials are composed of individual water boxes composed, for example, of copper and containing cooling channels in which cooling water is circulated. Due to the large cooling effect, a thin layer of slag freezes onto the inner surface of the water box and protects the same from corrosion due to the hot, corrosive slag bath. As a result of their size, the water boxes which extend over the entire height of the slag bath are relatively heavy and cumbersome. Replacement of the individual water boxes is only possible with a cold furnace because with a hot furnace the immediately adjacent water boxes which are rigidly clamped at their outside seize as a result of their thermal expansion. Even if the abutting surfaces of the horizontally adjacent water boxes were to be shaped conically, it would only be each second water box which would be directly detachable without the adjacent water boxes having to be previously detached.
SUMMARY OF THE INVENTION
The present invention provides a furnace system having furnace walls whose water boxes or cooling elements come into contact with the molten slag and can be readily attached and detached so that they can be individually replaced immediately after tapping the slag with a hot furnace when repairs are required. Consequently, only short operating interruptions of the furnace system occur.
In the improved furnace system of the present invention, the cooling means which come into contact with the slag consist of horizontally disposed, plate-shaped cooling elements which are provided with cooling channels and are arranged one above the other. Such cooling elements preferably consist of copper or other highly heat conductive metal. A plurality of such cooling elements are arranged one above the other and are releasably secured to a common, door-like cooling element carrier preferably consisting of sheet steel or the like. The door-like cooling element carriers can be pivoted from the cooling wall by means of joints or hinges which in turn are supported to supporting elements at the outside of a stationary supporting structure. The comparatively lightweight cooling elements are easily manipulated during assembly and disassembly. When repair is required, the slag situated in the furnace is tapped, the support elements between the door-like cooling element carriers and the stationary support structure are removed, and the cooling element carriers can then be pivoted out of the furnace wall toward the outside and the individual cooling elements released. Typically, the cooling elements can be releasably secured to the cooling element carriers by means of a slide connection which can be quickly replaced and can even be interchanged because the individual cooling elements are of the same size. Operating interruptions resulting from repair work on the cooling elements are thus reduced to a minimum.
With the improvements of the present invention, a clear separation is achieved between the cooling elements which have the cooling function and the carrying and support elements which support the same. The cooling water connecting lines of the plate-shaped cooling elements project out of the furnace wall toward the outside between the horizontally adjacent, door-like cooling element carriers. Because of the close sliding fit between the door-like cooling element carriers and the individual, plate-shaped cooling elements secured thereto, the latter are free to move as required by thermal expansion. The door-like cooling element carriers which are supported on the stationary support structure can likewise take part in thermal expansion. Overall, the structure of the present invention is characterized by a high ratio between the effective furnace wall cooling surfaces and the weight of the cooling elements while providing a very rapid accessibility to the inside of the furnace.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention are explained in greater detail on the basis of the embodiments shown in the drawings in which:
FIG. 1 is a vertical sectional view of an improved pyrometallurgical furnace system according to the present invention, taken along the line I--I of FIG. 2;
FIG. 2 is a horizontal cross-sectional view through the furnace system taken substantially along the line II--II of FIG. 1;
FIG. 3 is an enlarged illustration of the detail identified at III in FIG. 2;
FIG. 4 is a cross-sectional view taken substantially along the line IV--IV of FIG. 2;
FIG. 5 is a view similar to FIG. 1 but illustrating a modified form of the present invention, the view being taken substantially along the line V--V of FIG. 6; and
FIG. 6 is a cross-sectional view taken substantially along the line VI--VI of FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The pyrometallurgical furnace system shown in the drawings can be used, for example, for melting fine-grained, sulfidic lead ore concentrates. The drawings illustrate a melt 11 of lead having a molten lead surface 12 which collects in a furnace trough 10 supported from below over a suitable foundation. Situated above the bath is a slag bath 13 having a molten slag surface 14. The portion of the furnace wall coming into contact with the slag 13 is protected by individual plate-shaped cooling elements 15, 16, 17 and 18 horizontally arranged one above the other and preferably consisting of copper. Means are provided for circulating cooling water through each of the cooling elements 15 through 18. As a result of the strong cooling effect, a thin slag layer freezes onto the surface of the cooling elements 15 through 18, the slag layer protecting the surface of the cooling elements against corrosion due to the molten slag.
As clearly shown in FIG. 1, support elements 19 project from the backs of the cooling elements 15 through 18, the cooling elements being inserted into horizontal rails 20, 21 by means of the support elements 19, the rails 20 projecting from the front side of a cooling element carrier 22 which consists of a sheet steel housing or the like which is open toward the outside. Upper and lower hinged joints 25, 26 are disposed in the cooling element carrier 22 between arms 23, 24 whereby the hinged joints 25, 26 are secured to a vertical carrier 29 through additional hinge means 27, 28. In order to relieve the stresses on the joints and hinges, the underside of the cooling element carrier 22 is supported against the furnace trough 10 in the operating condition.
In the sample embodiment shown in FIG. 1, four plate-shaped cooling elements 15 through 18 are horizontally disposed above each other and are releasably secured to the common cooling element carrier 22 by the sliding engagement previously described. Three such horizontally adjacent cooling element carriers 22, 30 and 31 can be seen in FIG. 2, each of which carries four plate-shaped cooling elements. The cooling element carrier 30 includes a hinged joint 32 and the cooling element carrier 31 has a hinged joint 33 whereby each cooling element carrier can be pivoted out of the furnace wall in door-like fashion toward the outside of the furnace in the direction of the arrow 34 by means of the respective joints. This condition is illustrated in FIG. 2 wherein the cooling element carrier 31 carrying plate-shaped cooling element 35 through which cooling water is flowing has just been pulled out for replacement in the direction of the arrow 36, with the lower cooling element 37 still being in its inserted operating position.
As seen in FIG. 2, the stationary support structure includes vertical carrier beams 29, 38, 39 and 40 spaced by a distance, for example, of 2.40 meters which corresponds to the spacing of the joints 26, 32, 33 of adjacent cooling element carriers 22, 30, 31 and which also approximately corresponds to their horizontal length. The vertical carrier beams 29, 38, 39 are connected to each other by means of horizontal beams 41 and 42. Wedges 47 through 50 are insertable between the horizontal carriers 41, 42 and inside stiffening ribs 43 through 46 attached to the cooling element carriers 22, 30 so that the cooling element carriers despite their pivotal capability are securely supported in the operating condition. With the length of each plate-shaped cooling element being about 2.40 meters, the height of all four cooling elements disposed above one another may amount, for example, to approximately 1.30 meters. The hinged pivot points of the individual cooling element carriers preferably are in proximity to one end of the carriers.
As seen in FIGS. 2 and 3, the horizontally adjacent cooling element carriers 30, 22 have a spacing gap therebetween through which a cooling element 51 secured to the cooling element carrier 30 is directed toward the outside with its longitudinal end 52 being bent toward the outside at one side wall as well as being provided with cooling water intake and discharge lines 53 and 54. The adjacent cooling element carriers 30, 22 are connected to each other in the area of the spacing gap by means of a clamping device 55 such as a screw bolt. As shown in FIG. 3, the spacing gap is sealed by means of packing glands 56 consisting, for example, of asbestos which when starting up the furnace system provides a gas-tight seal of the inside space of the furnace.
As seen in FIG. 1, the plate-shaped cooling elements preferably consist of copper having a cooling water inlet 56 and a cooling water outlet channel 57 connected thereto and lying thereabove. It can be seen from FIG. 4 that the lowest cooling element 51c of the four cooling elements 51, 51a, 51b and 51c is connected to a cooling water intake line 58 and the uppermost cooling element 51 is connected to a cooling water discharge line 54 and that the cooling water channels of the adjacent cooling elements are connected to one another by means of U-shaped pipe bends 53.
In the embodiment shown in FIG. 5, the cooling elements 59, 60 preferably consisting of copper have an angular shape in vertical section so that their edges enclose the upper and lower surfaces of the cooling element carriers 61. The pivotal joints 62, 63 may be composed of sheet steel.
With the type of structure shown in FIGS. 5 and 6, the transition of the furnace wall area from the lower cooling element 60 up to the furnace trough 10 is well protected because as a result of the large cooling contact surface, a frozen protective slag layer is formed at the inside wall of the furnace as well as at any inside wall gaps which may exist during operation of the furnace system. Overlapping portions 64, 65 of mutually adjacent cooling elements 66, 60 in the area of the spacing gap between mutually adjacent cooling element carriers 67, 61 are also provided.
Thermal expansion in the furnace wall is absorbed by the close sliding fit between the cooling elements and the carriers as well as, according to FIG. 2, the bearing 68 of the hinges 69 which can be displaced in the horizontal direction and which carry the joint 33 of the respective cooling element carrier 31. A similar sliding capability is provided at the opposite end of the horizontal carrier beam 41.
In the case of repair being necessary to one or more of the cooling elements in the furnace system, the slag 13 is first run off. Then the clamping means 55 or one of the other clamping means is released. After the wedge pieces 49, 50, as well as the horizontal carriers 42 at the neighboring location have been dismantled, the respective cooling element carriers after detaching the cooling water intake and discharge conduits, can simply be pivoted out of the furnace wall toward the outside in the direction of the arrow 34. Consequently, this change can be made while the furnace is still hot. Then the damaged cooling element such as element 35 is simply withdrawn and is replaced by a new cooling element so that the replaced element can be repaired at leisure. In the reverse sequence, the furnace is once again closed and placed in operation. Operating interruptions of the furnace system caused by repair to the cooling elements are thus reduced to a minimum.
It should be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention. | The present invention deals with an improved pyrometallurgical furnace system of the type in which the melt and/or slag comes into contact with cooled furnace walls. The improvements of the present invention are directed to mechanical structures in which the cooling elements are sectionalized and are releasably secured to cooling element carriers, with pivotal means being provided to enable the cooling element carriers to be pivoted into position providing access to the cooling elements which are releasably secured to the carriers. | 5 |
[0001] This application is a continuation of U.S. Non-Provisional Application Ser. No. 14/838,872, filed Aug. 28, 2015, the entire disclosure of which is incorporated herein by this reference.
TECHNICAL FIELD
[0002] This invention relates to a structural building element. More particularly, this invention relates to roof or floor frame supports. Still more particularly, this invention concerns beams for building construction and particularly timber beams for house construction.
BACKGROUND
[0003] The following references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the following prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the present invention of which the identification of pertinent prior art proposals is but one part.
[0004] It is known to build floor joists from a top and bottom chords with an open web made of a pair of zigzag steel strips nailed to the sides of the timber chords. The chords may be spliced to each other with halving joists. Such a joist is described in US 2006/0156677 A1.
SUMMARY OF INVENTION
Technical Problem
[0005] The steel joists leave no pathway for ducts, pipes and cables to cross the building through the joists. The earlier timber joists have great shear strength but limited torsional strength. By trading off shear strength the inventor has achieved significant advantages.
[0006] The apparatus aspect of the invention provides a timber T or I-beam comprising a top plate and/or a bottom plate forming the flanges of an I-beam and a series of side by side timber blocks, each separated from the next by a gap, together forming a uniplanar intermittent web, the blocks oriented so that their grain extends transverse to the general longitudinal axis of the top plate.
[0007] In this document, in discussing the terms flange, chord or plate, the word “chord” generally refers to an elongate length of timber forming part of a truss, the word “flange” refers to an elongate length of timber forming part of a beam, whereas the word “plate” is used as a generic term. In discussing the words “board” or block”, these words are generally interchangeable and generally refer to a short span of timber extending from a plate or between a pair of plates. The pitch or rake of a roof surface, or the roof frame or truss members that support and/or form part of the roof structure, describes the angle of inclination achieved on the surface.
[0008] The I beam may be used as a building element of a roof truss or other roof frame. The top and bottom plates may extend parallel to one another. The blocks may be cut square. The top and bottom plates may be set at an incline with respect to one another. The top plate may be set on an incline relative to the square bottom edge of each of the blocks or may extend parallel thereto. The rake of an inclined plate may be minimal, for example around 3°. The rake may vary to achieve roof pitches between 1° and 45°. Where the T or I beam forms an A-frame, a double rake may be provided.
[0009] The top and bottom plates may be made of timber of a width larger than the thickness of the boards forming the web. The term plates is used in the framing sense in that they are the horizontals which act as a contact surface for other components and connect the upright parts of the beam.
[0010] The blocks may be of rectangular section, or trapezoid or other irregular shape to follow the desired inclined surface of the plate. The face of the plate which contacts the web may be prepared to include grooves or may be rough sawn.
[0011] Advantageously, the rake on the plate may be 1° to 3° and still require no modifications of the rectangular sectioned blocks. Greater raking will generally require planing or cutting of one end of the block to follow the incline of the plate.
[0012] The depth of the plate may be 25-110 mm, the width 30-150 mm.
[0013] The web may extend along at least the intermediate part of the beam. The ends of the I or T beam may be devoid of gaps in order to provide a beam which can be docked at one or both ends. So the blocks at one or both ends are greater lengthwise than the blocks separated by gaps.
[0014] The blocks are aligned so that their grain extends transversely relative to the T or I beams longitudinal axis. It is believed that significant gains in torsional strength are achieved whilst trading off on shear lineal strength, which is still more than sufficient due to the tensional strength of the plate and the blocks aligned with their grains generally transverse to the longitudinal axis of the plates.
[0015] The horizontal sides of the blocks may also be planed and secured to the plates by adhesive. The sides of the blocks may project slightly into a longitudinal shallow housing in the plates.
[0016] The width of the gaps may be equal along the length of the beam. The gaps width may be substantially equal to the length (the direction parallel to the longitudinal axis of the plate) of the blocks. The gap width will normally be selected to allow plumbing pipes, airconditioning ducts and extractor ducts to pass through thereon, together with smaller components such as water pipes and cables. The gap range may be preferably 90-500 mm.
[0017] The beam may be made from structural pine for internal use. For external use treated pine of structural grade containing arsenic is suitable. Laminated timber plates and blocks may be used instead but at higher cost. The type of material used to form such I-beams and T-beams as described herein in accordance with the invention may be made from machine grade pine (MGP) or laminated veneer lumber (LVL), the latter being considered a generally higher grade material. Such materials may be used to achieve beams having short duration modulus elasticity (E values) of 6,100-21,500, preferably about 10,000, which correspond to MGP10. Most typically I-beams made according to the invention are required to conform to stress grade standards of F5-F27, but most typically will fall within the stress grade range of F8-F17, corresponding to E values of 9,100-14,000. For house construction, the plates may be 45-90 mm and preferably 70-90 mm in width and 35-45 mm in depth. The blocks may be 70-190 mm, preferably 90-140 mm in length (the direction parallel to the longitudinal axis of the plate), 90-190 mm, and preferably 35-45 mm in depth, noting that the height between the plates may vary depending on the application.
[0018] Polyurethane adhesives suffice for indoor work. Exterior polyurethane glues are preferable for joints which support balconies and outdoor structures.
Advantageous Effects of Invention
[0000]
1. The beam is versatile in the way it incorporates into existing building construction.
2. Its gaps allow transverse passage of pipes, ducts and cables.
3. It offers a useful range of spans.
4. It is economical in that it allows utilisation of short pieces of block which would otherwise be scrapped.
5. It permits the economical production of timber I and T construction beams.
6. By orienting the blocks transversally, it permits the production of raked roof truss elements with minimal modification of component parts relative to beams with parallel plates. The narrower block width allows an inclined beam surface to still rest stably on its end, even if minimally raked by an incline of, say, 1°-3°.
[0025] 7. It allows efficient production of a range of raked roof truss elements through a range of inclinations by simple cutting of the angles of the respective blocks to length and inclination.
BRIEF DESCRIPTION OF DRAWINGS
[0026] Various embodiments of the invention are now described with reference to the accompanying drawings, in which:
[0027] FIG. 1 is a perspective of a 6 m beam.
[0028] FIG. 2 is a side view of the beam when chamfered at the end support.
[0029] FIG. 3 is a side view of the beam supported at one end in an alternative manner.
[0030] FIG. 4 is a side view of two beams joined at 90 degrees.
[0031] FIG. 5 is an end view of the beam supported on a conventional stud wall.
[0032] FIG. 6 is a side view showing the beam intersecting with a mid span/end span blocking lying in one of the gaps.
[0033] FIG. 7 is a side view of part of a floor with the beam beneath projecting outside the first floor timber wall as a cantilever.
[0034] FIG. 8 is the same as FIG. 7 with alternative detail.
[0035] FIGS. 9, 10 and 11 are side views of the beam connected in alternative ways to a steel I-beam.
[0036] FIG. 12 is a diagram of a jig in which the beam components are arranged prior to glueing.
[0037] FIG. 13 is a side view of a plano-convex beam.
[0038] FIG. 14 is a side view of a biconcave beam.
[0039] FIG. 15 is an end view of three I-beams braced by two bracing components.
[0040] FIG. 16 is a side view of a plano convex beam of I-section.
[0041] FIG. 17 is a side view of a biconcave beam of I-section.
[0042] FIG. 18 is a side view of a slightly raked beam of I-section;
[0043] FIG. 19 is a side view of an A-frame beam of I-section, slightly raked from a centre high point;
[0044] FIG. 20 is a side view of a raked beam of I-section;
[0045] FIG. 21 is an amplified view of the centre point of the embodiment shown in FIG. 19 ;
[0046] FIG. 22 is a perspective view of an I-beam in the process of being manufactured;
[0047] FIG. 23 is a perspective view of the I-beam of FIG. 22 during manufacture;
[0048] FIG. 24 is an end schematic view of a timber T-beam;
[0049] FIG. 25 is an end schematic view of a timber I-beam according to the invention;
[0050] FIG. 26 is a side art cross sectional view of a raked I-section beam according to the invention;
[0051] FIG. 27 is a side schematic part view of an I-beam with parallel chords;
[0052] FIG. 28 is an end schematic view of a wall and roof truss frame combination comprising a double raked A-frame roof structure;
[0053] FIG. 29 is an end view of a steeply pitched single raked building structure;
[0054] FIG. 30 is a perspective view of a block; and
[0055] FIG. 31 is a schematic end view of a plate.
DESCRIPTION OF EMBODIMENTS
[0056] Referring now to FIG. 1 , the beam is made of structural pine. Top chord 2 and bottom chord 4 are made of sawn 6000×90×35-45 mm scantlings. Laser guided sawing is adequate surface finish. The web is made of nine boards, 198×240×45 mm, the sides 8 of which are glued to the faces of the chords with polyurethane. The grain of the boards lies parallel to the chords. The boards are separated from each other by a 190-320 mm rectangular gap 10 which is large enough to admit 90 mm PVC tubes or 300 mm duct. The chords 2 , 4 create a 23 mm wide step 12 where the board meets the chord. The nine web boards 6 are separated from each other by eight equal gaps. The two outer boards 14 , 16 are separated from the outermost boards 18 , 20 , each a minimum 600 mm long by gaps 22 , each 198 mm wide. These can be varied in gap width to suit the construction for which they are intended. The outermost boards are made intentionally about 2.5 times the length of the web boards 6 to allow onsite docking if necessary.
[0057] In FIG. 2 outermost web board 18 and the overlying end of chord 2 are docked at incline 24 to allow the beam to rest on plate 26 within the thickness of stud wall 28 .
[0058] In FIG. 3 chords 2 , 4 project into the walls top and bottom plates 32 , whereafter the end blocking board 34 is fixed to the members 2 , 4 , 34 .
[0059] In FIG. 4 beam 36 intersects beam 38 at 90 degrees. Both chords 2 , 4 are cut back to allow outermost board 16 to project into the space between steps 10 . A steel joist hanger 40 mutually connects the beams. The top chords of both beams are united by skew nail 42 .
[0060] FIG. 5 shows an end view of a plurality of the bottom chords of beams 36 that are skew nailed to the top plate 44 and particle board flooring 46 is fixed to the top chords.
[0061] In FIG. 6 , when the beams are arranged in a parallel series across a building they are stabilised by the insertion into gap 8 of a common structural board such as a strongback 48 which is skew nailed to the chords and the upright end of web board 6 .
[0062] In FIG. 7 ground floor timber supporting wall 50 supports the beam such that it acts as a cantilever. The projecting extension portion 52 supports exterior flooring 54 . The end which is inside the building is connected by a joist hanger 40 to a twin beam 56 which abuts floor 58 . Packers 60 lie between top chord 2 and inside floor sheets 58 .
[0063] In FIG. 8 the endmost board 62 is made of treated pine and covered with exterior flooring sheets 54 .
[0064] In FIG. 9 ceiling battens 64 are fixed to bottom chord 4 to take plaster board sheets 66 . A steel I-beam 68 supports the timber beam 32 . A 35 mm timber packer 70 is secured to the web of the steel beam 68 by bolts 72 and angle bracket 74 joins outermost board 16 to the packer 70 . The chord 2 is cut back to allow the appropriate insertion.
[0065] In FIG. 10 the same arrangement is shown again with packer 70 resting on the flange 76 of the I-beam. Instead of bracket 74 , steel joist hanger 40 connects outermost board 16 to the packer.
[0066] In FIG. 11 the chords are cut back to allow the outermost board 16 to project between the steel I-beam flanges 76 . The board is fastened with bolts 78 to cleat plate 80 .
[0067] In FIG. 12 a jig for beam assembly is shown, wherein a first angle iron clamp 82 is positioned alongside a row of flat, horizontal spacer supports 84 intended to raise the web boards. An opposing angle iron clamp 86 is positioned alongside and parallel to the row of spacers 84 . Posts 88 are welded to the clamps at mid point and the posts are joined by threaded rods 90 . Nuts 92 impose the clamping force.
[0068] The chord plates 2 , 4 are laid between the spacers and the clamps and the boards 6 are aligned with the spacers. Glue 94 is applied from a gun and the clamps are tightened. In some beams the grain of the boards lie at 90 degrees to the axis of the plates.
[0069] The clamps have pairs of holes 96 for each board so that nails can be inserted through the clamps, the plates 2 , 4 and into the boards 6 after gluing.
[0070] Referring now to FIG. 13 , the beam has a top plate 2 and a bottom plate 4 joined by web boards 6 . The gaps 10 between boards are the same but the outermost board 20 has a cut out 82 measuring 345×120 mm. The LH end of the beam is 405 mm deep and though the beam length varies, the outermost end of the beam would typically be 300 mm. The saw is programmed to modify the depth of the web boards to reduce the beam height from the inner end to the outer end. This achieves the pitch required to make a flat roof self draining. However, because the web boards 6 have substantial length the direction of the I-beam axis, they each must be individually cut, despite the shallow raked angle of 1-2°. However, it is not possible to cut them too short in their axial grain orientations.
[0071] In FIGS. 14 and 15 a pair of brace boards 84 , 86 , the same depth as web boards 6 in FIG. 13 , are glued and nailed to top plate 88 and bottom plate 90 . The boards lie end to end in contact and project 22 mm beyond the plates at both ends.
[0072] The purpose is to lead to installation as shown in FIG. 15 . Here the component is lowered into the gap between a pair of adjacent parallel I-beams 92 , 94 and rotated to lie 90° to both. Alternatively, the bracing component may be installed as the I-beams are laid. The plates 88 and 90 are skew nailed to the top plates of the I-beam alongside using nails 96 and to the wall plate beneath using nails 98 .
[0073] Referring now to FIG. 16 , a top plate 2 is laminated to produce a convex shape as shown. A saw bench which docks the boards 6 is programmed to cut the boards 6 in a series to produce the shape shown. The jig is modified accordingly. Likewise in FIG. 17 , the jig is further modified to produce the biconcave beam shown.
[0074] Turning to FIG. 18 , there is shown a raked I-beam comprising a lower chord 104 and an upper chord 102 interposed by equispaced blocks 106 . The lower chord 104 extends flat along a tabular jig 109 , whereas the upper chord 102 declines at an angle (about 0.5-30°, preferably about 0.5-5°, and most preferably 1.5° from an end point 115 to an outer end 116 , where the I-beam 101 is cut to suit outer roofing profiles, such as guttering and outer frame structures, and for this reason the outer most block 106 comprises a board 118 that can be docked and cut to shape and size to suit the desired profile as shown in the drawing. It is noted that the description in relation to FIG. 18 is with regard to an A-frame I-beam, but the relevant description is applicable to single raked I-beams, such as those shown in FIG. 20 .
[0075] Turning to FIG. 19 , a shallow A-frame 201 is shown having a high centre point 215 from which the raked upper chords 202 a, b decline either side of the centre point 215 . The lower chord 204 lies flat on the planar jig 209 and interposed between the lower and upper chords 202 , 204 are a plurality of equispaced blocks 206 advantageously cut square to minimize costs, each block 206 beam cut the length to support the upper chords 202 a, b in raked position through to the outer most long board 218 a, b at either end.
[0076] In FIG. 20 , single raked I-beams are shown having a pair of upper and lower chords 302 , 304 that are most likely spaced at a first end point 315 and converge at an angle of about 2-5° to a second end point 316 . As with the embodiment shown in FIG. 18 , the single raked I-beam 301 comprises a plurality of blocks 306 each spaced to support and brace the upper and lower chords 302 , 304 . Interstitial spaces 322 provide gaps to allow ducting, wiring and other building services to be passed through the I-beam 301 during the building phase, as well as once the building is erected. As shown in FIG. 21 , the interstitial spaces 222 of A-frame I-beam 201 may be in registry with one another in situ to enable the passage of such building services. The blocks 206 may be cut square where the raking angle is shallow, such as 1-5°, or may be cut at one end to conform to the angle of incline to ensure that the upper chord 202 rests stably on each block 206 , as will be explained in more detail with reference to FIG. 26 .
[0077] With reference to FIG. 22 , during manufacture the upper and lower chords 402 , 404 may be placed on a planar jig table 409 and braced in place using spacer blocks 413 . Initially only one chord 404 is placed in position, glue is applied to predetermined regions on the chords internal surface 405 who correspond with the positioning of the end of face of each block 406 , 418 that is to be placed in that glued region, the glue being a high strength semi-rigid external use polyurethane adhesive. The blocks 406 , 418 are positioned in place and supported, spaced above the tabular jig 409 in a parallel horizontal plane by board spaces 484 positioned between the table 409 and the boards 406 , 418 . The second upper chord 402 is then placed with its wide face against the other end of the blocks 406 , 418 , but not before adhesive is similarly applied to corresponding regions along its inner face 407 .
[0078] As shown in FIG. 23 , the upper and lower chords 404 , 402 are then compressed together by clamps 490 and the boards, blocks 406 , 418 are secured in position between the upper and lower chords 402 , 404 by the application of nails through the outer surfaces of the chords 402 , 404 into the ends of the blocks 406 , 418 to secure the blocks 406 , 418 until the adhesive can form a strong bond, noting that it is the adhesive that provides the long term mechanical strength or the I-beam 401 . During manufacture, preferably a pair of nails 712 are inserted through the upper and lower chords 702 , 704 into each block 706 at each end of the block 706 to prevent twisting. To further secure the I-beam structure 701 , screws 711 are inserted intermittently along the length of the I-beam 701 to hold or further clamp the boards or flanges 702 , 704 in place against the adhesive 707 until the adhesive 707 sets, preferably at 500-1500 mm intervals along the length of the I-beam 701 .
[0079] The I-beam 401 is then removed from the jig 409 and the process is repeated to form a new I-beam 401 .
[0080] The adhesive may be a high strength, semi-rigid polyurethane glue.
[0081] Turning to FIGS. 24, 25, 30 and 31 , the I-beam may be substituted with a timber T-beam that may be defined with respect to the following dimensions:
W=width of the chord, which may typically be 30-150 mm, preferably 44-120 mm, and most preferably 70-90 mm; D=depth of chord 502 which may be 25-110 mm, more preferably 30-70 mm, and most preferably 35-45 mm; H=height of block 50-400 mm, most preferably 70-290 mm, noting that H can vary depending on the pitch of the truss I-beam or T-beam, the position of the block 506 along the length of the I-beam or T-beam 501 and the mechanical properties required of the block 506 for the particular application; t=thickness of the block 506 which may be 19-90 mm, but more preferably 35-45 mm. Note: The web of the T-beam may or may not be continuous.
[0087] Similarly, with respect to the I-beam 601 shown in FIG. 25 and more clearly shown in FIG. 30 , the block t value may be 10-90 mm and preferably 35-45 mm, the latter using F grade or machine graded pine (MGP). The value w may be 50-240 mm, preferably 70-140 mm, and most preferably 70-90 mm. The raking angle may vary to accommodate different applications and may be between 0.4°-45°, with H being varied with the pitch angle.
[0088] As shown in FIG. 26 , the achievement of blocks 706 having a relatively small w value (for example 70 mm, and in some applications, as low as 45 mm), allows the block 706 to be cut square whilst still adequately supporting the inclined raking chord or flange 702 .
[0089] A similarly formed I-beam 801 is shown in FIG. 27 formed using similar principles to the I-beam 701 described with reference to FIG. 26 .
[0090] Referring to FIG. 28 , there is shown a combined wall frame and roof truss structure using parallel I-beams 801 made according to the invention. In FIG. 29 , there is shown a building structure with a single inclined I-beam span. It is noted that the parallel chords of the portal structure shown in FIGS. 28 and 29 can be replaced with dual raked roof truss structures (for the example shown in FIG. 28 ) and with a single raked I-beam structure (see the example shown in FIG. 29 ).
[0091] It is to be understood that the word “comprising” as used throughout the specification is to be interpreted in its inclusive form, ie, use of the word “comprising” does not exclude the addition of other elements.
[0092] It is to be understood that various modifications of and/or additions to the invention can be made without departing from the basic nature of the invention. Materials other than timber are suitable for making into boards. Polymeric timber substitutes are suitable if they have suitable strength. These modifications and/or additions are therefore considered to fall within the scope of the invention. | A timber I-beam 701 has a top chord 702 and a bottom chord 704 forming the flanges of I-beam and a series of side by side timber blocks 706 each separated from the next by a gap 722, together forming a uniplanar, intermittent web. Cables and pipes for a building may run transversely through the gaps 722. A method of making the I-beam is described. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing a carbon fiber by using pitch as starting material, and more particularly to a process for infusibilizing pitch fiber which comprises subjecting a pitch fiber to an oxidizing treatment to convert it to an infusible fiber.
2. Brief Description of the Prior Art
Recently, the process for producing a carbon fiber by using pitch as starting material has been watched with interest. The merit of this process consists in that a less expensive carbon fiber can be produced by it because pitch is less expensive than the starting materials of the prior processes such as PAN (polyacrylonitrile) and rayon, that a carbon fiber of high strength and high elasticity can be produced without carrying out the complicated stretching treatment in the firing process if a liquid crystal is used as the starting material of spinning, and that yield of carbonization is high. Thus, it is actively being studied and developed today.
The production of carbon fiber using pitch as starting material generally starts from the preparation of spinning pitch. Thus, crude coal tar pitch, petroleum pitch or the like, used as raw material of the process, is subjected to various treatments such as distillation, heat treatment, filtration, hydrogenation, fractionation using solvent, and the like either alone or in combination to remove the components obstructing the spinning process, such as low-boilding point volatile components, insoluble solid components and the like, from the pitch, to homogenize the quality of pitch and to make its quality appropriately heavy. Thus, an optically isotropic or optically anisotropic spinning pitch is obtained. The properties of a spinning pitch can be evaluated by measuring various parameters such as softening point, melt viscosity, optical structure, composition revealed by solvent fractionation, etc., and various spinning pitches different in properties can be used for spinning. Fundamentally, however, it is important that the spinning pitch contains no solid nor gas under the conditions of spinning and has a uniform flow property.
In the next stage, the resulting spinning pitch is formed into fiber to obtain a pitch fiber. Usually, melt spinning is suitable for producing a continuous long fiber, and centrifugal spinning is suitable for producing cotton-like short fiber or producing a drawn and arranged assembly of medium fiber having a medium length, i.e. sliver or two. The spinning temperature, hall number, drawing rate, stretch ratio, etc. may be selected appropriately so as to meet with the desired purpose. The spun pitch fiber usually has a fiber diameter of about 5 to 30μ (microns). If the fiber diameter is too great, the fiber properties are apt to deteriorate. If the fiber diameter is too small, an economical spinning process is difficult to secure.
In converting the pitch fiber into a carbon fiber, the thermoplastic pitch fiber must be subjected to an oxidative treatment prior to the carbonization with heat, by which the pitch fiber is converted to an infusible fiber or a fiber which does not fuse even if heated (the so-called infusibilizing treatment). Usually, the infusibilization is achieved by subjecting a pitch fiber to an addition reaction of oxygen or an oxidizing substance and thereby crosslinking the pitch molecules. For this purpose, various oxidizing gases and liquid or solution-formed oxidants have hitherto been proposed. Since this type of reactions progress from the surface of fiber, a pitch fiber of smaller diameter is expected to be infusibilized more rapidly. In the infusibilizing process, the pitch fiber is handled either in the form of being rolled and packaged, or in the form of being stretched continuously, or in the form of being accumulated on conveyer or in basket. An appropriate form may be selected depending on the intended final form of the fiber.
Next, the infusibilized fiber is heated in an inert gas at a temperature of about 600° to 3,000° C. to convert it to a carbon fiber (carbonization; when the temperature of this treatment is higher than 2,000° C., it is sometimes called "graphitization"). By this treatment, the volatile components present in the infusibilized fiber and the part having a thermally instable structure in the pitch molecule are decomposed and vaporized off, and the aromatic ring structure in the molecule is grown. Thus, the fiber becomes rich in carbon content and sometimes becomes close to graphite crystal, and there is obtained a carbon fiber having high strength and elastic modulus.
For practising the heating, hot air oven, electric furnaces using various heating elements, plasma furnace and the like can be used. Since a large quantity of energy is consumed in any of these cases because of the high temperature, it is necessary to carry out the carbonization with a high efficiency. If desired, the carbonization may be carried out in two stages (low and high temperatures) or in more stages.
If desired, the carbon fiber thus obtained is further subjected to surface treatment, oiling, unwinding, and sometimes cutting, fibrillation, etc. However, these treatments will not be mentioned herein because of their generality.
All the above-mentioned processes are important for producing a carbon fiber. Among them, the infusibilizing step usually takes a long period of time and various troubles deteriorating the performances of carbon fiber often occur in this step. Accordingly, effective practice of this process is quite important to an economical production of carbon fiber.
The infusibilization is carried out for the purpose of oxidizing the thermoplastic pitch fiber to convert it into an infusible fiber having no thermoplasticity and thereby preventing the softening and deformation of the fiber in the subsequent carbonizing step. For achieving this purpose, a pitch fiber is usually heat-treated and oxidized while slowly elevating its temperature in an oxidizing gas. If control of this reaction is unsatisfactory, an uncontrollable reaction takes place to incur melting, inflammation, etc. Even if such uncontrollable reactions do not take place, a phenomenon called "sticking" often takes place to make the practice of this process difficult. As used herein, the term "sticking" means such a phenomenon that, in the infusibilizing process, adjacent pitch fibers are softened and deformed or sometimes a third material adheres to the contact area of the plural pitch fibers and, as its result, the pitch fibers are fixed together.
In a sticked pitch fiber, the fibers keep fixed after the subsequent carbonization, so that it lacks flexibility and its commercial value is damaged greatly. Sometimes, such a fiber has no commercial value at all.
The sticking phenomenon is apt to occur when pitch fiber is handled in the form of a tow or a strand. The handling of pitch fiber in the form of tow or strand is most suitable for the production of continuous filament, and it is quite difficult industrially to obtain a continuous carbon fiber of high quality by other methods such as drawing and arranging cotton-like or wool-like pitch fiber after infusibilization or after carbonization. Viewed from another angle, however, the infusibilization of pitch fiber in the form of tow or strand is not advantageous in the point of prevention of sticking. For, in the form of tow or strand, pitch fibers are bundled at a high density and have many contact points successively in the longitudinal direction. If a pitch fiber is heated in such a state for the purpose of infusibilization, the softened pitch fiber is readily stuck together at every contact point. In addition, the heat generated by the oxidation of pitch is accumulated in the tow or strand, which locally elevates the temperature of tow or strand and induces melting and sticking of mutually contacted pitch fibers. Further, the volatile substances evaporated from pitch fiber or the substances exuding out of pitch fiber cannot be rejected outside the fiber bundle but they are accumulated at the contact points, which acts as a sort of binder to cause the sticking.
Regarding the infusibilization of pitch fiber, a variety of techniques have hitherto been proposed. They include the method using a solution of oxidant (for example, Japanese Patent Publication No. 21,904/72, Japanese Patent Publication No. 21,905/72, etc.), the method using an oxidative gas (for example, Japanese Patent Publication No. 42,696/73, Japanese Patent Kokai (Laid-Open) No. 75,828/74, etc.), the combined use of the above-mentioned two agents (for example, Japanese Patent Kokai (Laid-Open) No. 88,729/76, Japanese Patent Kokai (Laid-Open) No. 30,915/84, etc.), and the like. However, the effect which these techniques exhibit is predominantly a shortening of the period of time required for infusibilization, and none of these methods is satisfactory from the viewpoint of preventing the sticking of pitch fibers. Further, the use of an oxidant such as hydrogen peroxide, chromic acid and the like is undesirable from the viewpoint of the safety of the process.
As a method for preventing the sticking of pitch fiber strands, combined use of a water-soluble oxidant, a water-soluble surfactant and finely powdered graphite has also been proposed (Japanese Patent Kokai (Laid-Open) No. 128,020/80). However, this technique also uses an oxidant, and therefore it is not desirable from the viewpoint of safety, as has been mentioned above.
Accordingly, an object of the present invention consists in providing a process for the infusibilization of pitch fibers having an effect of preventing the sticking of tow-formed or strand-formed pitch fibers at the time of infusibilizing treatment. Another object of the invention consists in providing a process for the infusibilization of pitch fibers exhibiting the above-mentioned effect without using those oxidants which are dangerous from the viewpoint of safety.
The process of the invention having the above-mentioned effect is surprisingly simple. Thus, the objects of the invention can be achieved by treating a pitch fiber with a dispersion of a finely powdered solid lubricant in water or a solvent prior to the infusibilizing treatment (at an appropriate time selected out of the period from the prevention of melting to the infusibilization) and heat-treating the pitch fiber to which the finely powder of solid lubricant adheres in an oxidative gas to perform the infusibilization.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term "solid lubricant" means a solid material which is used in the form of a thin film or a powder for the purpose of protecting the surface of relatively moving bodies against the injury caused by the motion and decreasing the friction and abrasion, and its known typical examples include the powders of graphite, molybdenum disulfide, tungsten disulfide, boron nitride, fluorinated graphite, talc and the like.
Among the materials, the powders of molybdenum disulfide and tungsten disulfide have an effect of preventing the sticking of pitch fiber, as mentioned in the preceding patent of the present inventors (Japanese Patent Application No. 281,318/84). Further, the sticking preventive effect of talc is also mentioned in the preceding patent of the present inventors (Japanese Patent Application No. 195,400/85).
Subsequently to the above-mentioned inventions, the inventors determined that materials capable of exhibiting such an effect are not limited to molybdenum disulfide, tungsten disulfide and talc but the particles of substances called "solid lubricant" are generally suitable for use in the prevention of pitch fibers from the sticking.
Thus, there was obtained a conclusion that applying a specified solid powder to pitch fiber followed by its infusibilization is necessary for preventing the sticking occurring in the process of infusibilization, that said solid must have a softness enough to protect the pitch fiber against injury and at the same time a lubricant performance enough to prevent the abrasion between pitch fibers, and that the materials called solid lubricant above are most suitable for satisfying the above-mentioned conditions. Based on this finding, the present invention was accomplished.
The particle diameter of the solid lubricant suitable for use in the invention is as follows. Thus, since the mechanism of the prevention of sticking according to the invention consists in forming interstices between pitch fibers, particles of which diameter is smaller than a critical value (for example, 0.5μ) are inferior in the sticking preventive effect. Further, the use of unnecessarily fine particles is disadvantageous from the economical point of view. On the other hand, since pitch fibers usually have a fiber diameter ranging from about 5μ to 30μ, too coarse particles having a diameter exceeding about 5μ, for example, are difficult to make uniformly permeate between fibers. Further, if the particle is coarse, its dispersion cannot keep a sufficient stability. From the viewpoint mentioned above, the preferable range of particle diameter is about 0.5μ to about 5μ.
As used herein, the term "dispersion" means a material prepared by dispersing a powder of solid lubricant into an appropriate dispersion medium. It includes those of which dispersion stability is enhanced by a combination of physical means. As the solvent, a variety of solvents such as hexane, heptane, methanol, ethanol and the like can be used, among which methanol and ethanol are preferred. Water is also usable as said solvent. Strong solvents for pitch such as quinoline, chloroform and the like are undesirable, because they can injure the pitch fiber. The use of benzene is also restricted for the same reason as above. Solvents of which the boiling point or boiling point range is higher than 200° C. are undesirable, because they obstruct the flow of oxidative gas. In the invention, the solid lubricant is used in the form of a dispersion because it facilitates a uniform treatment and it readily permeates into the spaces between fibers.
In carrying out the treatment, the dispersion is used either as it is or after adjusting its concentration to an appropriate value. The concentration of solid lubricant powder used for the treatment is preferably in the range of 5 to 50%. Although solvent systems require no particular assistant at the time of treatment, aqueous systems require use of a surfactant for the purpose of improving the wettability of pitch fiber. As said surfactant, any of the cationic, anionic and nonionic surfactants can be used. Among them, the nonionic surfactant is preferred because it is not affected by the ions of other components present in the dispersion. Examples of said nonionic surfactant include polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ether and ester, ethylene oxide-propylene oxide block copolymer, and the like. The use of the surfactant in too large an amount is undesirable because it obstructs the flow of oxidative gas. On the other hand, if its amount is too small, the effect of wetting and dispersing is insufficient. Usually, the surfactant is preferably used in an amount of about 0.5 to 1.0%.
The treatment of pitch fiber with the dispersion may be carried out at any appropriate time selected out of the range from the time just after the fiber formation of pitch fiber to the time just before the infusibilization. As the method of the treatment, various methods such as spray coating, roller coating, dipping and the like can be used. At any rate, the powder of solid lubricant must be applied to the pitch fiber as uniformly as possible.
As has been mentioned above, general solid lubricants can be used for preventing sticking occurring in the process of infusibilization. More preferably, however, a substance exhibiting an excellent property not only in the infusibilization process but also in the subsequent carbonization process should be selected.
This is for the following reason. Thus, because the infusibilized fiber (the fiber after the infusibilization) is still fragile, the solid lubricant powder applied to pitch fiber prior to the infusibilization treatment is usually not removed from the infusibilized fiber, but the infusibilized fiber having the solid lubricant powder adhering to its surface is directly introduced into the carbonization process.
Accordingly, it is preferable that the solid lubricant used in the invention remains stable during the heat-treatment in the infusibilization process which is carried out in an oxidative atmosphere at a maximum temperature of 250° C. to 400° C. and, at the same time, it remains stable also during the heat-treatment in the carbonization process which is carried out in an inert atmosphere at a maximum temperature of 600° C. to 3,000° C. It is particularly desirable that the solid lubricant remain stable under the condition of heat-treatment at 1,000° C. or above which is a necessary condition of carbonization for manifesting sufficient strength of carbon fiber.
The inventors have repeatedly studied the above-mentioned points to find that, among the known solid lubricants, graphite, boron nitride and fluorinated graphite fulfill the above-mentioned condition.
Graphite is stable up to a temperature somewhat higher than 450° C. in an atmosphere of air and up to a temperature somewhat higher than 2,500° C. in an inert atmosphere. Boron nitride is stable up to a temperature somewhat higher than 500° C. in an atmosphere of air and up to a temperature somewhat higher than 2,000° C. in an inert atmosphere. Fluorinated graphite is stable up to 400° C. in the atmosphere of air. Although it decomposes at a temperature higher than 400° C., the product of the decomposition is graphite. This means that fluorinated graphite shows a stability equal to that of graphite at a temperature higher than 400° C.
Based on these facts, it will be understandable that applying the powder of graphite, boron nitride or fluorinated graphite to pitch fiber is effective for preventing the sticking of pitch fiber in the infusibilization process and, in addition, it exercises no influence upon the carbon fiber in the process of carbonization practised at a temperature higher than 1,000° C., so that it is a method suitable for the production of carbon fiber of high performances.
Whether the spinning pitch used as the starting material of pitch fiber to which the present invention is applied is an optically isotropic pitch or an optically anisotropic pitch, the effect of the invention can be exhibited.
As the state of pitch fiber, a loosely drawn and arranged state (the so-called tow state) or the tightly drawn and arranged state (the so-called strand state) is preferred. The state of cotton where short fibers are entangled at random and the state of wool (silver) where long fibers separated from one another are accumulated are also employable. Since the latter two states originally have only a small number of contact points, the effect of the invention is not great there.
After applying the solid lubricant powder, the fiber is heat-treated in an oxidizing atmosphere while elevating the temperature, to practise the infusibilization. As the oxidizing gas for the infusibilization, air, oxygen, ozone, nitrogen dioxide, sulfur dioxide, halogen and the like can be used, among which air and oxygen are preferable from the viewpoint of economy. The rate of the elevation of temperature is preferably about 2° C. to 10° C./minute, and the maximum temperature of the treatment is 250° C. to 400° C.
When the invention is applied, the use of those oxidants which have been used in the prior processes can be excluded, which makes the procedure quite safe. Further, by applying the above-mentioned speed of temperature elevation, the period of time required for infusibilization can be varied at will. For example, the period of time required for infusibilization can be made as short as 30 to 120 minutes. It should be noted here that, according to the prior processes using an oxidant only, the sticking could not be prevented even if consuming a period longer than 120 minutes and a carbon fiber of high quality could be obtained only by consuming a yet longer period of time for the infusibilization.
The infusibilization system of the invention can directly be introduced into the carbonization process, without carrying out washing or the like particularly.
If a tow or a strand, i.e. an assembled bundle of fibers, is wet with water, the fibers adhere to one another and, as the result, the shape of the tow or strand becomes more slender than before the wetting, generally speaking, and this slender shape is maintained as it is throughout the infusibilization process and the carbonization process, roughly saying. Such a mutual adhesion of filaments usually promotes the sticking of the filaments in the infusibilization process. According to the present invention, nonetheless, the pitch fiber treated with a dispersion of solid lubricant powder can easily be separated into individual filaments by mildly stroking it after the infusibilization and carbonization processes, and there is obtained a carbon fiber free from sticking.
Such an excellent effect is attributable to that the solid lubricant powder uniformly applied to pitch fiber enters the interstices between pitch fibers to produce fine gaps there, owing to which the contact points between pitch fibers causing the stocking are eliminated and the oxidizing gas becomes flowing between the fibers. Thus, the oxidation reaction can progress uniformly, and the volatile substance generated from pitch fiber at the time of infusibilization can be removed rapidly.
Next, examples of the invention will be mentioned. The examples mentioned herein are only for facilitating the understanding of the process of the invention and its effect and by no means for limiting the scope of the invention.
EXAMPLE 1
An optically anisotropic pitch containing 40% of quinoline-insoluble component, prepared from coal tar, was subjected to melt spinning process to obtain a pitch fiber strand having a fiber diameter of 13μ and a filament number of 2,000. On the other hand, a natural flaky graphite powder having a mean particle diameter of 0.6μ was dispersed into ethanol to prepare three ethanolic dispersions having concentrations of (a) 5% by weight, (b) 10% by weight and (c) 20% by weight. Then, the strand obtained above was dipped into each of these dispersions to obtain three kinds of graphite powder-attached pitch fiber strands. Each of the treated strands was heat-treated in an atmosphere of oxygen at a temperature elevation rate of 5° C./minute and infusibilized over a period of one hour. The infusibilized fiber was then carbonized by heat-treating it in an atmosphere of argon up to a temperature of 1,100° C. to obtain a carbon fiber. The carbon fiber thus obtained could easily be split into individual filaments, and no sticking was noticeable in any of (a), (b) and (c).
In a sedimentation test of the above-mentioned three graphite dispersions, all the dispersions remained stable for a period of 60 minutes or more without showing any sedimentation of graphite powder.
EXAMPLE 2
Three kinds of carbon fibers were prepared by repeating the procedure of Example 1, except that the natural flaky graphite having a mean diameter of 0.6μ was replaced with a boron nitride powder having a mean particle diameter of 0.5μ. The three carbon fibers thus obtained could easily be split into individual filaments without noticeable sticking.
In the sedimentation test of the three kinds of dispersions, all the dispersions kept stable for 60 minutes or more.
EXAMPLE 3
A pitch fiber strand obtained by the same procedure as in Example 1 was dipped in a 10% (by weight) methanolic dispersion of fluorinated graphite powder having a mean particle diameter of 1.2μ to obtain a treated strand. It was heat-treated in an atmosphere of air at a temperature elevation rate of 2° C./minute and infusibilized over a period of 2 hours. The infusibilized fiber thus obtained could easily be split into individual filaments without noticeable sticking.
In the same sedimentation test as above, the dispersion remained stable for 60 minutes.
EXAMPLE 4
An optically anisotropic pitch containing 40% of quinoline-insoluble component, prepared from coal tar, was subjected to a melt spinning process. While carrying out the spinning, the spun fiber was coated just underneath the spinning furnace with a dispersion containing 15% by weight of natural flaky graphite particle having a mean particle diameter of 3μ and 0.5% of polyoxyethylene nonylphenol ether as a surfactant by means of revolving rolls to obtain a treated pitch fiber strand having a fiber diameter of 14μ and a filament number of 400. The pitch fiber strand was infusibilized in an atmosphere of oxygen over a period of 2 hours at an temperature elevation rate of 2° C./minute, and subsequently it was heat-treated in an atmosphere of argon up to a temperature of 1,500° C. for the sake of carbonization to obtain a carbon fiber. The carbon fiber thus obtained could easily be split into individual filaments without noticeable sticking.
In the same sedimentation test as above, the dispersion remained stable for 30 minutes.
EXAMPLE 5
A carbon fiber was produced by repeating the procedure of Example 4, except that the natural flaky graphite particles used in Example 4 was replaced with a boron nitride powder having a mean particle diameter of 0.5μ. The carbon fiber thus obtained could easily be split into individual filaments without noticeable sticking.
In the same sedimentation test as above, the dispersion remained stable for 60 minutes or more.
EXAMPLE 6
An optically isotropic pitch containing 60% of benzene-insoluble component and having a softening point of 230° C., prepared from coal tar, was subjected to a melt spinning process to obtain a pitch fiber strand having a fiber diameter of 13μ and a filament number of 2,000. Then, the strand was dipped in a 10% (by weight) dispersion of natural flaky graphite powder having a mean particle diameter of 0.6μ in acetone to obtain a graphite powder-attached pitch fiber strand. The strand was infusibilized by heat-treating it over a period of 2 hours in an atmosphere of oxygen at a temperature elevation rate os 2° C./minute. Then, the infusibilized fiber was heat-treated in an atmosphere of nitrogen up to a temperature of 1,000° C. for the sake of carbonization to obtain a carbon fiber. The carbon fiber thus obtained could easily be split into individual filaments without sticking.
In the same sedimentation test as above, the dispersion remained stable for 60 minutes or more.
COMPARATIVE EXAMPLE 1
A pitch fiber strand obtained by the same procedure as in Example 1 was dipped in each of the following three liquids: (a) water, (b) ethanol, (c) 20% aqueous solution of hydrogen peroxide. The three kinds of treated strands thus obtained were insolubilized and carbonized by the same procedure as in Example 1. As the result, a sticking took place to give only a rod-like carbon fiber bundle in all of the cases (a), (b) and (c).
COMPARATIVE EXAMPLE 2
A pitch fiber strand obtained by the same procedure as in Example 1 was dipped in each of the dispersion prepared by dispersing a boron nitride powder having a mean particle diameter of 0.5μ into (a) quinoline, (b) chloroform and (c) benzene. The three kinds of treated strands thus obtained were infusibilized and carbonized by the same procedures as in Example 1. As the result, the strand (a) melted in the course of infusibilization. Although the strands of (b) and (c) could be infusibilized and carbonized, the carbon fibers thus obtained were sticked together and were difficult to split into individual filaments. | The present invention relates to a process for the infusibilization of pitch fiber which comprises, in the production of pitch type carbon fiber, attaching a powder of solid lubricant to a pitch fiber and then subjecting the pitch fiber to an infusibilizing treatment. According to the present invention, the use of oxidant used in prior processes can be excluded, the process can be operated with a high safety, and the period of time required for the infusibilization can be shortened. Further, the infusibilized fiber obtained according to the invention can directly be introduced into the carbonization process, without any particular washing treatment and the like. | 3 |
BACKGROUND
[0001] Nets used for backyard or recreational badminton, volleyball and other net-sports can be burdensome and time consuming to initially set up because it typically requires the user to attach eyebolts or brackets with eyelets to the support poles and then tie the top and bottom net cords to the eyes. Additionally, when it comes time to take down the net, many users find it too time consuming and burdensome to untie the knots to remove the net from the poles and so they simply role the whole net assembly up around the poles. By not removing the net from the poles, the net becoming tangled with the guy-ropes other net components or the net will become entangled with other items where the net is stored thereby making it more burdensome and time consuming to set up the net the next time it is desired to be used.
[0002] Accordingly, there is a need for a sports net assembly that simplifies the initial set and subsequent set ups of the net and which makes it just as simple to disassemble the net after game play so as not to discourage users from completely disassembling the net from the support poles for proper storage. Additionally it is desirable to incorporate into the sports net assembly a simple and effective way to adjust and maintain the desired tension on the net during game play.
DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is an elevation view of an embodiment of a sports net assembly with an embodiment of a net attachment and tensioning system.
[0004] FIG. 2 is an enlarged perspective view of a portion of the net attachment and tensioning system of FIG. 1 showing an embodiment of a pole cap and cam for supporting and tensioning the top net cord.
[0005] FIG. 3 is an enlarged perspective view of a portion of the net attachment and tensioning system of FIG. 1 showing an embodiment of a key lock for releasably securing the bottom net cord to the pole.
[0006] FIG. 4 is a plan view of an embodiment of a cam for the net attachment and tensioning system of FIG. 1 .
DESCRIPTION
[0007] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, FIG. 1 illustrates an embodiment of one side of a sports net assembly 10 , it being understood that the other side is a mirror image of the side illustrated in FIG. 1 .
[0008] The sports net assembly 10 includes a net 12 operably supported between spaced apart support poles 14 by a top net cord 16 and a bottom net cord 18 utilizing the net attachment and tensioning system 100 (discussed later). Guy-ropes 20 are provided to stabilize and hold the poles 14 so the net remains in place during game play and to resist the tendency of the poles to tip inwardly under the weight of the net 12 . The guy-ropes 20 are secured at one end to the ground by stakes 22 . The other end of the guy-ropes 20 are preferably releasably attached to the poles 14 as described later. Length adjusters 24 , as are well known in the art, may be provided to allow the user to adjust the length of the guy-ropes 20 as desired to adjust and plumb the poles and/or to increase or decrease tension or pull on the net 12 to reduce sag in the net between the poles.
[0009] The poles 14 , may comprise a single pole or a number of pole sections which fit together. The poles 14 are preferably thin-walled tubular members such that the poles are light weight yet sufficiently rigid to adequately support the net without buckling. The cross-section of the tubular members may be round, square or other shape to provide the desired rigidity. In a preferred embodiment, the poles 14 include a ground member 30 having a pointed end 32 that is hammered into the ground as an anchor for the poles. A pole receiving end 34 of the ground member 30 preferably projects a distance above the ground to be telescopically received by the bottom end 36 of the tubular pole member. The ground engaging member 30 , is preferably configured and made of a material that can withstand repeated hammering without the pole receiving end 34 mushrooming or becoming deformed.
[0010] The net attachment and tensioning system 100 preferably includes a pair of pole caps 102 . Each pole cap 102 preferably sits over the top end of each pole 14 or is otherwise secured proximate the top end of each pole. The pole cap 102 has first and second hooks 104 , 106 through which a length of the top net cord 16 passes as best illustrated in FIG. 2 .
[0011] The net attachment and tensioning system 100 also preferably includes a cam 110 that is slidably disposed along the pole 14 . The cam 110 includes a slot 112 into which the top net cord 16 is removably receivable. A ball or knot 114 is preferably provided at the end of the top net cord 16 to prevent the top net cord from pulling through the slot 112 . The cam 110 includes an aperture or opening 118 ( FIG. 3 ) that is preferably slightly larger than, but complimentary to, the outer periphery of the pole 14 so that when the cam 110 is positioned so that it is in a plane substantially perpendicular to, or normal to the pole 14 , the cam 110 will freely slide up and down along the pole. However, because the aperture 118 is preferably only slightly larger than the outer periphery of the pole, if the cam is angled or canted, the aperture walls 120 ( FIG. 3 ) will make contact with the pole 14 and the frictional resistance between the aperture walls 120 with the pole 14 will cause the cam 110 to frictionally lock relative to the pole until it is again positioned in the slidable position where it is in a plane substantially perpendicular or normal to the pole. Accordingly, as illustrated in FIG. 2 , the net attachment and tensioning assembly provides a simple and effective way to adjust and maintain the desired tension on the net during game play by simply sliding the cams 110 down relative to the top end of the poles 14 . This downward movement of the cam 110 will result in an increase in tension or pull on the top net cord 16 which will reduce net sag. To easily disassemble the net from the poles, the cam 110 is moved upward along the pole 14 to decrease tension on the net cord 16 so the cord can be easily removed from the slot 112 . The length of the top net cord 16 can then be removed from the hooks 104 , 106 on the end cap 102 freeing the top net cord 16 from the poles 14 .
[0012] In a preferred embodiment, the cam 110 is preferably made of a substantially rigid material so that it will not bend or deform under the pulling force or tension exerted by the top net cord 16 received within the slot 112 . It is also preferred that the aperture walls 120 are made of material with a high friction factor, such as rubber to provide a better frictional lock to resist sliding of the cam relative to the pole. To provide the desired rigidity while at the same time providing the desired high friction rubber material at the aperture walls 120 , the cam 110 is preferably fabricated using a double injection molding process wherein the body of the cam is made of plastic or other suitably rigid material while the aperture walls are made of rubber or other high friction factor material.
[0013] Referring to FIG. 3 , the net attachment and tensioning system 100 also preferably includes key locks 130 for securing the bottom net cord 18 and guy-ropes 30 to the poles 14 . The key locks 130 include keys 132 that cooperate with mating pre-drilled key holes 134 in the poles 14 . Each key 132 preferably includes an eyelet 136 to which the bottom net cord 18 is attached. The other end of each key 132 preferably has an elongated shape that is receivable by the mating pre-drilled key hole 134 such that when the key 132 is inserted into the key hole 134 and partially twisted or rotated, the elongated shape of the key 132 will not pull through the key hole 134 . The pre-drilled key holes 134 ensure that the bottom net cord 18 and guy-ropes 20 are attached in the proper position. The net bottom cord 18 and guy-ropes 20 are preferably securely fixed to the eyelets 136 of the keys 132 in a pre-assembled manner at the factory, such as by use of a clamp 138 forming a loop around the eyelet 136 , so that the user does not have to bother with tying the cords 18 or guy-ropes 20 to the keys 132 during the initial set-up of the net.
[0014] It should be appreciated that the foregoing net attachment and tensioning system 100 simplifies the attachment of the net and guy-ropes to the poles during initial set-up and makes the disassembly of the net and guy-ropes from the poles just as easy and efficient so users are not discouraged from completely disassembling the net and guy-ropes from the poles during take-down of the net after game play. As such, each subsequent set-up of the net follows the same simple procedure as the initial set up. Furthermore, the net attachment and tensioning assembly 100 provides a simple and effective way to adjust and maintain the desired tension in the net during game play by simply sliding the cams 110 up and down relative to the poles 14 .
[0015] The foregoing description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment of the apparatus, and the general principles and features of the system and methods described herein will be readily apparent to those of skill in the art. Thus, the present invention is not to be limited to the embodiments of the apparatus, system and methods described above and illustrated in the drawing figures, but is to be accorded the widest scope consistent with the spirit and scope of the appended claims. | A sports net assembly and method of assembling a sports net assembly. The sports net assembly includes a pair of poles spaced a distance apart and positioned substantially vertically. A net having opposing ends is positioned between the spaced apart substantially vertical poles. The top net cord is secured to a cam that is slidably movable along a length of the poles to increase and decrease the tension on the top net cord thereby increasing and decreasing sag in the net between the poles. The bottom net cords and guy-ropes may be releasably secured to the poles with a key lock. | 0 |
PRIORITY
[0001] The present application is a continuation of U.S. patent application Ser. No. 10/610,045, filed Jun. 30, 2003, the content of which is incorporated herewith in its entirety.
TECHNICAL FIELD
[0002] The present invention is related to information gathering with automated systems. More particularly, the present invention is related to obtaining profile information from individuals with automation where the profile information is applied for subsequent uses.
BACKGROUND
[0003] Various automated services may be provided for individuals that are specialized for the particular preferences and situation of each individual. For example, an automated system may assist in making purchases for an individual such as automatically purchasing flowers each year on a birthday through an electronic transaction. As another example, an automated system may assist in setting up a dinner reservation for an individual through an electronic transaction. For these transactions, individual specific information must be known, such as the date and type of flowers to purchase or the time and place to schedule the reservation as well as the smoking preference.
[0004] Profile information for individuals may specify the preferences and factual scenarios such as birthdays of interest for an individual. This profile information may be accessed by automated systems when assisting with purchases, scheduling, etc. so that the individual is not required to provide this information for each task being performed. However, this profile information must be acquired from the individual before it can be put to use by the automated systems.
[0005] Acquiring such profile information can be a tedious task. An individual could be asked to complete a questionnaire. However, the information that is relevant to services to be provided for a particular individual at any given time may be difficult to anticipate such that a script of questions intended to elicit that information cannot be prepared in advance. Furthermore, the amount of information may be lengthy such that the individual is required to remain focused on answering numerous questions for an uncomfortable period. As a result the individual may become agitated and may provide hasty answers that are not useful to building the profile for the individual.
SUMMARY
[0006] Embodiments of the present invention address these issues and others by providing methods and systems that obtain information from individuals using automation. These embodiments present questions and analyze the answers that are received. The analysis of answers provides the basis for the selection of the next questions to be asked so that the questioning of the individual can effectively proceed.
[0007] One embodiment is a method of obtaining profile information from individuals using automation. The method involves providing a first question to an individual over a communication network from a network-based computer-implemented application. A first answer to the first question is received from the individual over the communication network at the network-based computer-implemented application. The first answer is analyzed with the network-based computer-implemented application, and based on the analysis of the first answer, a second question is selected and provided to the individual over the communication network from the network-based computer-implemented application.
[0008] Another embodiment is a system for obtaining profile information from individuals using automation. The system includes a profile database storing profile information for an individual. A network-based computer-implemented application is linked to the individual by a communication network. The network-based computer-implemented application is configured to provide a first question to the individual over the communication network and also receive a first answer from the individual over the communication network. The network-based computer-implemented application analyzes the first answer to select a second question and provides the second question to the individual over the communications network. A second answer to the second question is received over the communications network and profile information is determined from the first and second answers. The profile information is stored in the profile database.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows one illustrative embodiment of a system for obtaining profile information from individuals.
[0010] FIG. 2 illustrates one set of logical operations that may be performed within the system of FIG. 1 to obtain the profile information.
DETAILED DESCRIPTION
[0011] Embodiments of the present invention provide an individual with a network-based service that obtains profile information from the individual so that the other network-based services may utilize the profile information when performing automated tasks for the individual. The individual is thereby relieved from manually filling out tedious questionnaires with fixed sets of questions. Also, the questions are presented to the individual while accounting for the manner in which the individual is responding so that the questions can be tailored to minimize the aggravation to the individual.
[0012] FIG. 1 illustrates one example of an encompassing communications network 100 interconnecting communications devices of the individual with the network-based system that automates the profile building process. The individual may access the system through several different channels of communication including both data communication and verbal communication. As discussed below, the individual communicates verbally with a voice services node that may be present in various locations for different embodiments.
[0013] As one example, the individual may place a conventional voiced telephone call from a telephone 112 through a network 110 for carrying conventional telephone calls such as a public switched telephone network (“PSTN”) or adapted cable television network. The call terminates at a terminating voice services node 102 of the PSTN/cable network 110 according to the number dialed by the individual. This voice services node 102 is a common terminating point within an advanced intelligent network (“AIN”) of modern PSTNs or adapted cable networks and can be implemented as a soft switch and media server combination.
[0014] Another example of accessing the system is by the individual placing a voiced call from a wireless phone 116 . The wireless phone 116 maintains a wireless connection to a wireless network 114 that includes base stations and switching centers as well as a gateway to the PSTN 110 . The PSTN 110 then directs the call from the wireless phone 116 to the voice services node 102 according to the number dialed by the individual on the wireless phone 116 . Furthermore, the wireless phone 116 may function as a thin client device relative to the verbal functions of the automated profile building system such that the wireless phone 116 implements a distributed speech recognition (“DSR”) platform to minimize the information transmitted through the wireless connection. The DSR platform takes the verbal communication received from the individual at the wireless device 116 and generates parameterization data from the verbal communication. The DSR platform then transmits the parameterization data as the verbal communication to the voice service node 102 or 136 rather than all the data representing the verbal communications. The voice services node 102 or 136 then utilizes a DSR exchange function 142 to translate the DSR parameterization data into representative text which the voice services node 102 or 136 can deliver to an application server 128 .
[0015] Another example of accessing the system is by the individual placing a voiced call from a voice-over-IP (“VoIP”) based device such as a personal computer 122 or where telephone 112 is a VoIP phone. This VoIP call from the individual may be to a local VoIP exchange 134 which converts the VoIP communications from the individual's device into conventional telephone signals that are passed to the PSTN 110 and on to the voice services node 102 . The VoIP exchange 134 converts the conventional telephone signals from the PSTN 110 to VoIP packet data that is then distributed to the telephone 112 or computer 122 where it becomes verbal information to the individual. Furthermore, the wireless phone 116 may be VoIP capable such that VoIP communications occur with the wireless network 114 which are converted to speech prior to delivery to the voice node 102 .
[0016] The VoIP call from the individual may alternatively be through an Internet gateway 120 of the individual, such as a broadband connection or wireless data network 114 , to an Internet Service Provider (“ISP”) 118 . The ISP 118 interconnects the gateway 120 of the individual or wireless data network to the Internet 108 which then directs the VoIP call according to the number dialed, which signifies an Internet address of a voice services node 136 of an intranet 130 from which the automated service is provided. The voice services node 136 has the same capabilities as voice services node 102 like advanced speech recognition and text-to-speech, but is accessed over a VoIP network such as the Internet 108 . As shown, the voice services node is included within an intranet 130 that is protected from the Internet 108 by a firewall 132 . The voice service node 136 includes a VoIP interface and is typically implemented as a media server which performs the VoIP-voice conversion such as that performed by the VoIP exchange 134 . However, as discussed above, the voice services node 136 also performs text-to-speech and speech recognition such as that performed by the voice services node 102 and discussed below. Accordingly, the discussion of the functions of the voice services node 102 also applies to the functions of the voice service node 136 .
[0017] As yet another example, the wireless device 116 may be a wireless data device such as a personal digital assistant. The wireless device 116 and/or personal computer 122 may have a wi-fi wireless data connection such as IEEE 802.11 to the gateway 120 or directly to the wireless network 114 such that the verbal communication received from the individual is encoded in data communications between the wi-fi device of the individual and the gateway 120 or wireless network 114 .
[0018] Another example of accessing a voice services node 102 or 136 is through verbal interaction with an interactive home appliance 123 . Such interactive home appliances may maintain connections to a local network of the individual as provided through a gateway 120 and may have access to outbound networks, including the PSTN/cable network 110 and/or the Internet 108 . Thus, the verbal communication may be received at the home appliance 123 and then channel via VoIP through the Internet 108 to the voice services node 136 or may be channeled via the PSTN/cable network 110 to the voice services node 102 .
[0019] Yet another example provides for the voice services node to be implemented in the gateway 120 or other local device of the individual so that the voice call with the individual is directly with the voice services node within the individual's local network rather than passing through the Internet 108 or PSTN/cable network 110 . The data created by the voice services node from the verbal communication from the individual is then passed through the communications network 100 , such as via a broadband connection through the PSTN/cable 110 and to the ISP 118 and Internet 108 and then on to the application server 128 . Likewise, the data representing the verbal communication to be provided to the individual is provided over the communications network 100 back to the voice services node within the individual's local network where it is then converted into verbal communication provided to the individual.
[0020] The voice services node 102 provides text-to-speech conversions to provide verbal communication to the individual over the voiced call and performs speech recognition to receive verbal communication from the individual. Accordingly, the individual may carry on a natural language conversation with the voice services node 102 . To perform these conversations, the voice services node 102 implements a service control logic written in a language such as or similar to the well-known voice extensible markup language (“VoiceXML”) context which utilizes a VoiceXML interpreter function 104 of the voice services node 102 in conjunction with VoiceXML documents. An alternative language for the control logic is the speech application language tags (“SALT”) platform. The interpreter function 104 operates upon the VoiceXML or SALT documents to produce verbal communication of a conversation. The VoiceXML or SALT document provides the content to be spoken from the voice services node 102 . The VoiceXML or SALT document is received by the VoiceXML or SALT interpreter function 104 through a data network connection of the communications network 100 in response to a voiced call being established with the individual at the voice services node 102 . This data network connection as shown in the illustrative system of FIG. 1 includes a link through a firewall 106 to the Internet 108 and on through the firewall 132 to the intranet 130 .
[0021] The verbal communication from the individual is received at the voice services node 102 and is converted into data representing each of the spoken words through a conventional speech recognition and natural language understanding function of the voice services node 102 . The VoiceXML or SALT document that the VoiceXML or SALT interpreter function 104 is operating upon sets forth a timing of when verbal information that has been received and converted to data is packaged in a particular request back to the VoiceXML or SALT document application server over the data network. This timing provided by the VoiceXML or SALT document allows the verbal responses of the individual to be matched with the verbal questions and responses of the VoiceXML or SALT document. Matching the communication of the individual to the communication from the voice services node enables an application server 128 of the intranet 130 to properly act upon the verbal communication from the individual. As shown, the application server 128 may interact with a voice services node through an intranet 130 , through the Internet 108 , or through a more direct network data connection as indicated by the dashed line.
[0022] The voice services node 102 may also employ a voice analysis application 126 . The voice analysis application 126 allows various qualities of the individual's speech to be analyzed such as the energy, frequency, and various other speech parameters. For example, the tonal qualities of the speech can be analyzed to determine the gender of the individual as well as the individual's current mood. This information is delivered back to the application server 128 as data along with the data representative of the words that are spoken. The application server 128 may then analyze the qualities of the individual's speech along with the spoken content to determine which question(s) to subsequently present to the individual and when they should be presented. For example, the voice analysis application 126 may provide data to the application server 128 indicating that the individual is frustrated, such as because the individual's voice pitch has substantially increased. The application server 128 follows up by terminating the current session or asking a general question requiring a simple answer now while waiting until a subsequent session to ask a question for a current subject matter that requires a detailed answer.
[0023] The application server 128 is a conventional computer server that implements an application program to control the automated profile building service for the individual. Where verbal communication is utilized to communicate with the automated profile building service, the application server 128 provides the VoiceXML or SALT documents to the voice services node 102 to bring about the conversation with the individual over the voiced call through the PSTN/cable network 110 and/or to the voice services node 136 to bring about the conversation with the individual over the VoIP Internet call. The application server 128 may additionally or alternatively provide files of pre-recorded verbal prompts to the voice services node where the file is implemented to produce verbal communication. The application server 128 may store the various pre-recorded prompts, grammars, and VoiceXML or SALT documents in a database 129 . The application server 128 also interacts with a customer profile database 124 that stores the profile information for each individual that is acquired through the profile building process.
[0024] In addition to providing VoiceXML or SALT to the one or more voice services nodes of the communications network 100 , the application server 128 may also serve hyper-text markup language (“HTML”), wireless application protocol (“WAP”), or other distributed document formats depending upon the manner in which the application server 128 has been accessed so as to provide for non-verbal communication with the individual. For example, an individual may choose to communicate with the application server to build the profile information by accessing a web page provided by the application server to the personal computer 122 through HTML or to the wireless device 116 through WAP via a data connection between the wireless network 114 and the ISP 118 . Such HTML or WAP pages may provide a template for entering information where the template asks a question and provides an entry field for the individual to enter the answer that will be stored in the profile database 124 and/or will be used to determine the next question to provide on the template to seek further information from the individual.
[0025] The profile database 124 contains the preference information that has been provided by the individual through the profile building process. The profile database 124 may contain many categories of information for an individual. For example, the profile database 124 may contain payment preferences of the individual such as various credit accounts to be used. The profile database 124 may contain item preferences such as the permissible brands of products and services to be purchased and the permissible vendors that the purchase may be made from. As a specific example, the profile database 124 may specify the type of flowers to be automatically purchased each year on Valentine's Day and/or on a birthday. Additionally, the customer profile may specify the range of acceptable prices for the goods and services to be purchased.
[0026] As shown in FIG. 1 , the profile database 124 may reside on the intranet 130 for the network-based profile building service. However, the profile database 124 likely contains information that the individual considers to be sensitive, such as the credit account information. Accordingly, an alternative is to provide customer profile database storage at the individual's residence or place of business so that the individual feels that the profile data is more secure and is within the control of the individual. In this case, the application server 128 maintains an address of the customer profile database storage maintained by the individual rather than maintaining an address of the customer profile database 124 of the intranet 130 so that it can access the profile data as necessary.
[0027] FIG. 2 illustrates one example of logical operations that may be performed within the communications network 100 of FIG. 1 to bring about the automated profile building process for the individual. This set of logical operations is provided for purposes of illustration and is not intended to be limiting. For example, these logical operations discuss the application of VoiceXML within the communications network 100 where verbal communication occurs between the profile building system and the individual. However, it will be appreciated that alternative platforms for distributed text-to-speech and speech recognition may be used in place of VoiceXML, such as SALT as discussed above, or a proprietary less open method.
[0028] The logical operations of FIG. 2 may begin at question operation 202 where the application server distributes a question to the individual via email, other data messaging, or via a web template. Upon the first iteration where the first message has been sent to the individual or the individual has first visited the web page, then instructions may be provided to the individual to guide the individual in completing answers to the questions, such as by stating that the individual may answer in as general or detailed terms as desired and may terminate the question and answer session whenever the individual chooses. An example of an initial question may be to state the services that the individual will be using for which the customer profile information will be applicable. Another example of an initial question may be for the individual to identify himself or herself. When the logical operations begin at question operation 202 , then operational flow proceeds to answer operation 214 .
[0029] At answer operation 214 , the individual enters an answer to the question that has been presented when convenient for the individual. The answer is provided in a reply email or other data message or by entering text within the template of the web page. The individual may answer in general or detailed terms. For example, when asked which services the customer profile information will be applicable to, the individual may respond in general terms by entering only the basic name of each of the desired services. The individual may choose to respond in more detailed terms by elaborating on the services by also specifying key preferences for each of the services that should be contained within the profile database. As another example, when asked to identify himself or herself, the individual may simply enter the individual's name or may choose to elaborate by specifying name, age, and gender. After the individual provides the answer, operational flow transitions to analysis operation 216 .
[0030] The logical operations may alternatively begin at transfer operation 204 where the application server provides questions in the form of VoiceXML documents to a voice services node that has established a voiced call with the individual. The voiced call may be established at the initiative of the individual by dialing a number for the profile building service which results in a connection to the voice services node. Alternatively, the voiced call may be established at the initiative of the application server by instructing the voice services node to place a call to a known number for the individual.
[0031] Where the individual places the voiced call to the voice services node such as by dialing the number for the profile building service for the voice services node on the communications network or by selecting an icon on the personal computer where the voiced call is placed through the computer. The voice services node accesses the appropriate application server according to the voice call (i.e., according to the number dialed, icon selected, or other indicator provided by the individual). Utilizing the dialed number or other indicator of the voice call to distinguish one application server from another allows a single voice services node to accommodate multiple verbal communication services simultaneously. The voice services node may provide identification data to the application server for the individual based on the received caller ID information for the individual which allows the application server to create or access an existing profile for the individual.
[0032] Alternatively, the voice services node may implement a standard VoiceXML introduction page to inform the individual that he has dialed into the service and ask that the individual say his formal name or other form of identification, such as a user name and password. This identification can then be captured as data and provided back to the application server where it is utilized to create or access an existing profile for the individual.
[0033] Once the voice services node receives the VoiceXML document from the application server, it is interpreted at speech operation 206 to convert the VoiceXML text to speech that is then verbally provided to the individual over the voiced call. This verbal information may provide further introduction and guidance to the individual about using the system. This guidance may inform the individual that he can barge in at any time with a question or with an instruction. The guidance may also specifically ask that the individual provide a verbal answer to each question and that the verbal answer may be in as general or detailed terms as the individual chooses. The initial question is then provided verbally to the user. The speech from the voice services node may begin in a neutral tone and pace that may later be altered for subsequent questions depending upon analysis of the verbal answers received from the individual.
[0034] Eventually, the voice services node receives a verbal answer from the individual at answer operation 208 . The content of the verbal answer may be in general terms or may be detailed. For example, the verbal answer may be a one word, yes or no type of answer or the verbal answer may be several sentences that elaborate. Furthermore, the speech will have various characteristics such as pace and tonal qualities. The verbal answer is interpreted through speech recognition at the voice services node to produce answer data that represents the words spoken by the individual at recognition operation 210 . This data is representative of the words spoken by the individual that are obtained within a window of time provided by the VoiceXML document for receiving verbal answers so that the application server can determine from keywords of the answer data what the individual wants the service to do.
[0035] The voice services node also analyzes the voice characteristics of the verbal answer to quantify the characteristics such as pace and tonal quality to produce additional answer data. For example, the verbal answer may be slow and relatively low pitched indicating that the individual is in a calm mood and may be willing to participate for a while or may be fast and high pitched indicating that the individual is in an agitated mood and likely wants to be done with the session or the current line of questioning as soon as possible. Furthermore, the frequency content of the voice allows the gender to be estimated so that the gender specific questioning can be selected without specifically asking about gender and/or without receiving a specific answer about gender.
[0036] The answer data including the content of the verbal answer as well as the voice characteristics is transferred from the voice services node over the data network to the application server at exchange operation 212 . Operational flow then transitions to analysis operation 216 where the application server analyzes the answer data for the content and characteristics. Based on this analysis, the application server can then select the appropriate follow-up question with the individual from a hierarchy of question content, temperament, and timing. Such selection is discussed below with reference to selection operation 218 . In addition to analyzing the answer data so that the next question can be determined, the application server also analyzes the answer data to determine whether the content of the answer is appropriate for storage within the profile database for use by automated services performing tasks for the individual. For example, certain answers may be too vague or general to be useful and are not stored while other answers may directly address a category of information of the profile database. The answers adequately addressing a category of information of the profile database are stored for the appropriate category and for the individual.
[0037] Where the communication with the individual is text-based rather than verbal, then the characteristics of the text-based answer are analyzed for the length of the answer and the particular vocabulary used for the answer. For example, if the answers consist of only a few short words, then the application server may detect that the individual is in an agitated mood or that the individual does not type effectively. Where the communication with the individual is verbal, then the characteristics of the verbal answer are analyzed including the length of the answer as well as the voice characteristics discussed above that have been identified by the voice analysis at the voice services node. For example, the application server may recognize from the answer data that the verbal answer was lengthy, high-pitched, and fast paced which may indicate that the individual is not agitated with the questioning but that the individual has a personality that involves speaking quickly in a relatively high voice.
[0038] From the analysis, the application server then chooses the next content, temperament, and timing of the next question from the hierarchy of question options at selection operation 218 . For example, where the analysis has indicated that the individual is agitated, such as due to a verbal answer that had a higher pitch, faster pace, and less content than normal for this individual, then the application server may select a verbal question that requires only a yes or no answer, that is provided in a very soft-spoken voice presentation with a moderate pace from the voice services node, and is provided immediately. For example, the application server can provide a yes or no question immediately which can mean taking place a very short time following the previous question and taking place before any other questions or user interaction, while within the same session. The application server may also select a question that requires a more elaborate answer from the individual, that is provided in a neutral voice presentation in a quickened pace from the voice services node, and is set to be provided upon the next session that occurs between the automated profile building system and this individual.
[0039] The selection of questions may be based on statistical modeling that allows correlations of characteristics to be established. For example, the tonal qualities of speech may be correlated with mood and/or gender, while length of response may be correlated with mood and/or personality. From the correlations resulting from statistical modeling, the hierarchy of question content, temperament, and timing may be created and stored for application within the automated system.
[0040] Upon selecting the appropriate content of a question, as well as selecting the temperament including tone and pace and selecting timing for presentation to the individual, operational flow returns to question operation 202 or transfer operation 204 as appropriate for the current mode of communication with the individual. If the application server has selected that a question be present during the current session, then operational flow immediately continues at question operation 202 or transfer operation 204 . Otherwise, operational flow stops until the next session is initiated, and operational flow then re-starts at question operation 202 or transfer operation 204 .
[0041] The automated profile building system allows the individual to communicate with the system at the convenience of the individual and allows the individual to answer in a style that the individual chooses. The automated profile building system adapts to the current style of the individual to choose follow-up questions based on the analysis of the individual's answer. Accordingly, the follow-up questions may be provided with content, temperament, and timing such that the question and answer exchanges proceed in an effective manner as opposed to forcing the individual to answer a fixed set of questions that are not sensitive to the individual's personality, current mood, or other characteristic.
[0042] Although the present invention has been described in connection with various illustrative embodiments, those of ordinary skill in the art will understand that many modifications can be made thereto within the scope of the claims that follow. Accordingly, it is not intended that the scope of the invention in any way be limited by the above description, but instead be determined entirely by reference to the claims that follow. | Methods and systems obtain profile information from individuals using automation to select and provide the questions that are given to the individual. The answers the individuals provide to the questions can then be used to generate the profile information. Subsequent questions are selected and presented according to analysis of the previous answers. The exchange of the questions and answers occurs over a communications network and may take the form of emails, web page interfaces, wireless data messages, or verbal communication over a voiced call. The answers are analyzed to determine certain characteristics, such as the personality type, mood, and gender of the individual. The subsequent questions are selected based on the characteristics that are found from the answers to facilitate the information exchange between the automated system and the individual. | 6 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International Application No. PCT/EP2004/050569, filed Apr. 20, 2004 and claims the benefit thereof. The International Application claims the benefits of German Patent application No. 10332608.1 filed Jul. 17, 2003, all of the applications are incorporated by reference herein in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a method for regulating an internal combustion engine according to one or more physical models, wherein measurement values and adjustment values are provided as system parameters underlying the physical model. The invention also relates to a device for regulating an internal combustion engine according to one or more physical models.
BACKGROUND OF THE INVENTION
[0003] Engine controls for internal combustion engines normally use physical models which have parameters by means of which the ideal state of the internal combustion engine can be described. In reality, the underlying parameters of the physical model generally deviate from the real parameters of the engine. In order to match the physical models to the actual conditions in the internal combustion engine, adaptations of the parameters are carried out which are based on a comparison between measured parameters and theoretically expected values. The parameters are adapted by applying one or more adaptation values to said parameters.
[0004] It is desirable for the adaptations to be executed such that adaptation values are applied to those parameters of the physical models which are actually the cause of the deviation between the physical models and the real conditions in the internal combustion engine. If those parameters which are actually the cause of the deviation between model and reality are adjusted with the aid of adaptation values, the physical models deliver precise results even when there are rapid changes in the working point of the internal combustion engine without a repeat adaptation being required. If other parameters are adapted which are not the cause of the deviation between model and the real conditions, then a repeat adaptation is generally required when there is a change in the working point. The assignment of deviations to the correct system parameters (parameters) can, however, be difficult since the number of sensors for measuring the parameters is frequently limited.
[0005] Such a problem is present in internal combustion engines which have an intake manifold pressure sensor in an intake pipe but do not have an air mass sensor, particularly in internal combustion engines with variable valve control. The intake manifold pressure in such systems depends above all on the flow cross-section at a throttle valve and on the absorption capacity of the engine. The absorption capacity of the engine is essentially determined by the settings of the intake and outlet valves and/or by the rotational speed of the internal combustion engine. If the intake manifold pressure sensor identifies an intake manifold pressure which is higher than the theoretically expected value, then this may be caused by a greater flow cross-section at the throttle valve then specified by the corresponding parameter or by a lower absorption capacity than specified by the corresponding parameter. If in this state the flow cross-section of the throttle valve is adapted upwardly, then the calculated air mass becomes too great and the injection quantity is mistakenly raised. This results in too rich an air/fuel ratio in the combustion chamber of the internal combustion engine. The air/fuel ratio that is too rich can be detected by means of the lambda probe. The measured air/fuel ratio leads to an adaptation of the quantity of fuel injected, which is reduced as result, i.e. the corresponding adaptation value for the fuel quantity is decreased. The desired air/fuel ratio can in this way be maintained. Although the model for a specified working point of the internal combustion engine can in this way be brought into harmony with the measurement values, nonetheless incorrect parameters are adapted which determine at another working point defective model parameters so that an adaptation has to be carried out afresh. Under changing operating conditions, this would result in the underlying physical model having to be adapted constantly to the changed operating state. As a result, an adaptation of the physical model can be implemented only when the operating state is static.
[0006] Such a physical model for determining the air mass flow, which is determined with the aid of the measured intake manifold pressure, is known from publication WO 97/35106. Furthermore, an adaptation is provided for permanently adjusting the model parameters in a stationary and in a nonstationary operation in order to adapt the accuracy of the selected physical model.
SUMMARY OF THE INVENTION
[0007] The object of the present invention is to provide a method for controlling an internal combustion engine according to one or more physical models, wherein the parameters of the physical model can be adapted in an improved way. There is also provided a device for controlling an internal combustion engine which has a control based on one or more physical models, wherein the parameters of the physical model(s) are adapted in an improved way.
[0008] This object is achieved in the method according to the claims.
[0009] Further advantageous embodiments of the invention are specified in the dependent claims.
[0010] According to a first aspect of the present invention, a method is provided for controlling an internal combustion engine according to one or more physical models. Measurement values and adjustment values are provided as system parameters which underlie the physical model. One or more adaptation values, respectively, can be applied to the system parameters in order to adapt the physical model to real conditions of the internal combustion engine. Estimation parameters are determined by means of the system parameters, measurement parameters being determined in a measurement of the physical parameters underlying the estimation parameters. The measurement parameters are evaluated in relation to the estimation parameters and determined in accordance with an adaptation method with the aid of the measurement parameter adaptation values for at least a part of the system parameters. Depending on the adaptation values, a first operating mode or a second operating mode is adopted. The adaptation method is preferably implemented in the first operating mode and a further adaptation method implemented in the second operating mode.
[0011] In a preferred embodiment, a first estimation parameter and a second estimation parameter are determined by means of a first system parameter and/or a second system parameter and/or a third system parameter. In a measurement of a physical parameter underlying the first estimation parameter, e.g. in an exhaust pipe, a first measurement parameter is determined and in a measurement of a physical parameter underlying the second estimation parameter, e.g. in an intake pipe, a second measurement parameter is determined. The first measurement parameter is evaluated in relation to the first estimation parameter and the second measurement parameter is evaluated in relation to the second estimation parameter, a first adaptation value of the first system parameter being determined with the aid of the first measurement parameter. In a first operating mode, a second adaptation value for the second system parameter is determined with the aid of the second measurement parameter and a third adaptation value for the third system parameter is left unchanged. A change in the second adaptation value causes, due to the regulation, a change in the first system parameter. A second operating mode is adopted if the first adaptation value determined deviates from a neutral value by a first absolute on relative deviation value and the second adaptation mode determined in the first operating mode deviates by a second absolute or relative deviation value from a neutral value. In the second operating mode, the second adaptation value for the second system parameter is reset and the third adaptation value for the third system parameter determined with the aid of the second measurement parameter, the second adaptation value for the second system parameter being left unchanged after the resetting.
[0012] The inventive method has the advantage that when the system parameters underlying a physical model are adapted using measurement values, those system parameters are adapted which are probably the cause of the deviation of the actual conditions and the theoretical model. Since as a rule only a limited number of sensors are provided which can be used for adapting system parameters of the physical model, it frequently cannot be determined unambiguously which of the system parameters has to be adapted due to a deviation of a measured value from a theoretically expected value. This is the case when the deviation from the theoretically expected value can be caused by two or more deviations of system parameters.
[0013] If, when the physical model is adapted, two measurement parameters are determined, the adaptation of the second system parameter due to the regulation resulting in the first system parameter having to be readapted, then it can be assumed with a certain degree of probability that instead of the second system parameter the third system parameter has to be adapted if the adaptation value determined deviates from the neutral value by the first deviation value and second adaptation value deviates from the neutral value by the second deviation value. The neutral value is determined by the value at which no deviation is present, i.e. no adaptation has had to be or will have to be undertaken.
[0014] Thus, if it is ascertained that a second adaptation value, which in the course of the adaptation was changed by a specified deviation value, has to be applied to the second system parameter, and simultaneously a first adaptation value has to be applied to the first system parameter, then it may be obvious for the third system parameter to be adapted instead of the second system parameter and for the previous adaptation of the second system parameter to be returned to the initial value.
[0015] The advantage of the inventive method is that it can be ascertained from adaptation values already determined whether the adaptation of one of the system parameters corresponds to a deviation of a physical parameter underlying the system parameter or whether a deviation of another system parameter is present. If this is ascertained, according to the invention the adaptation of the second system parameter is terminated and an adaptation of the third system parameter carried out instead.
[0016] In principle, the system parameters of the physical model can be adapted in a random manner in order to provide suitable adapted system parameters for a specified working point. The adaptation of those system parameters which are responsible for the deviation between the estimation parameter and the measured value is, however, advantageous since, when there is a change in the engine working point no substantial change in the adaptation values is necessary if the correct system parameters have been adapted. If the wrong system parameters have been adapted, then a repeat adaptation is necessary at each new engine working point.
[0017] It can preferably be provided that the resetting of the second adaptation value is carried out gradually so that no abrupt change in the model parameters leads to an abrupt change in the third adaptation value. This could lead to a fluctuation of the physical model parameters since a change in a system parameter frequently leads to a change in a further system parameter only after a defined cycle time, so the adaptations of the system parameters would occur at staggered times relative to one another.
[0018] Alternatively, when the second adaptation value is reset, the second adaptation value can be switched to a corresponding modification of the first adaptation value and/or a corresponding third adaptation value. In this way, it is also possible to establish a “gentle” transition between the first and second operating modes.
[0019] Advantageously, the second operating mode is adopted if the first adaptation value determined is increased relative to the neutral value by the amount of the first deviation value and the second adaptation value determined in the first operating mode is reduced relative to the neutral value by the amount of the second deviation value or if the first adaptation value determined is reduced relative to the neutral value by the amount of the first deviation value and the second adaptation value determined in the first operation mode is increased relative to the neutral value by the amount of the second deviation value.
[0020] It can be provided that the first operating mode is adopted each time the internal combustion engine is started.
[0021] It can also be provided that after a specified period of time after the second operating mode has been adopted a switchover is made from the second operating mode to the first operating mode without the third adaptation value being reset. In this way, it is possible that after the adaptation of the third adaptation value in the first operating mode the second adaptation value can also be modified again and that an adaptation of the third and of the second adaptation value is possible.
[0022] A parameter which influences the opening time of a fuel injection valve is preferably provided as a first system parameter and/or a flow cross-section of the airflow let into the intake pipe as a second system parameter and/or an absorption characteristic curve of the internal combustion engine or a valve setting of an intake and/or outlet valve as a third system parameter.
[0023] It can also be provided that the air/fuel ratio in an exhaust pipe of the internal combustion engine is determined as a first measurement value and/or the intake manifold pressure in an intake manifold of the internal combustion engine as a second measurement value.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] A preferred embodiment of the invention is explained in detail below with reference to the attached drawings, in which:
[0025] FIG. 1 shows a schematic model of an internal combustion engine;
[0026] FIG. 2 shows a diagram of the absorption behavior of the internal combustion engine; and
[0027] FIG. 3 shows two flow diagrams for illustrating the inventive method.
DETAILED DESCRIPTION OF THE INVENTION
[0028] FIG. 1 shows schematically an internal combustion engine comprising a cylinder 1 . The cylinder 1 has a piston 2 and a combustion chamber 3 . A fuel/air mixture is supplied in an intake manifold 4 and can be let into the combustion chamber 3 via an intake valve 5 .
[0029] There is also provided an outlet valve 6 which is disposed on the combustion chamber 3 in order to discharge exhaust gas into an exhaust pipe 7 . The setting (relative opening and closing times) of the intake valve 5 and of the outlet valve 6 are controlled by a regulating unit (not shown) and are set with regard to the absorption behavior of the system as a whole.
[0030] Also disposed on the intake manifold 4 is an injection valve 9 in order to inject fuel. The quantity of fuel injected is determined by the opening time of the injection valve 9 . The opening time of the injection valve 9 is controlled by the regulating unit (not shown). The intake manifold 4 is also connected to an air feed 10 in order to feed air with a defined air mass flow to the intake manifold 4 . A throttle valve is disposed in the air feed 10 , which throttle valve can swivellably control the air mass flow into the intake manifold 4 . The throttle valve has a flow cross-section that depends on the control. The throttle valve 11 can be controlled via the regulating unit (not shown).
[0031] The internal combustion engine according to FIG. 1 is based on a physical model, according to which the mass flows into the intake manifold 4 and out of the intake manifold 4 determine the pressure in the intake manifold 4 . The pressure in the intake manifold 4 is essential to control of the internal combustion engine since the mass flow into the cylinder 1 is determined by means of the pressure and the absorption characteristic curve of the cylinder 1 . Since the settings of the intake and outlet valves, i.e. their phase position, influence the absorption behavior of the cylinder 1 , precise knowledge of the absorption behavior is required. According to a physical model on which the internal combustion engine is based, the pressure in the intake manifold is determined by:
P . im = R g · T im V im ( m . thr - m . cyl )
[0032] where T corresponds to the temperature in the intake manifold, V im to the volume of the intake manifold, {dot over (m)} thr to the air mass flow into the intake manifold, {dot over (m)} cyl essentially to the intake quantity of the air/fuel mixture fed to the cylinder 1 and R g to the gas constant of the air/fuel mixture. The equation shown represents a physical model by means of which the pressure in the intake manifold 4 can be determined.
[0033] In order to be able to operate the internal combustion engine 1 , knowledge of the air mass flow into the intake manifold is required. Due to component tolerances or other influences on the internal combustion engine, deviations from the theoretically expected value and the real values of parameters in the internal combustion engine can arise. For example, the air mass flow {dot over (m)} thr into the intake manifold 4 can have a different value than expected based on the flow cross-section of the throttle valve 11 . Such a deviation can arise due to faults or other tolerances.
[0034] It is also possible for the fuel quantity injected by the injection valve 9 not to match the quantity which would be expected on the basis of the control signal specified for the injection valve 9 . Thus, the quantity of fuel injected is determined by the opening time of the injection valve 9 ; however, due to component tolerances deviations can occur in the cross-section of the opening of the injection valve 9 . Furthermore, deviations can also occur due to component fluctuations between the calculated exhaust gas flow into the intake manifold 4 and the real exhaust gas flow into the intake manifold 4 .
[0035] Using a lambda probe 13 , it can be determined whether the combustion in the cylinder 1 has taken place with too rich an air/fuel mixture or too lean an air/fuel mixture. By means of a lambda regulation implemented in the regulating unit, the value for the air/fuel ratio is fed to a regulation by means of which the opening time of the injection valve 9 and consequently the quantity of fuel to be injected are controlled.
[0036] In order to establish whether there are deviations between the theoretically expected values and the real values, a pressure sensor 14 is disposed in the intake manifold 4 in order to record the pressure in the intake manifold. The value of the pressure in the intake manifold 4 is made available to the regulating unit. If the measured pressure deviates from the pressure theoretically expected in the intake manifold 4 , then there must be a deviation in one of the aforementioned system parameters.
[0037] In order to adapt the underlying physical model to reality, adaptation values are provided for each of the system parameters. The adaptation values are modifiable and adapt one or more of the system parameters such that the physical model for the working point adopted in the internal combustion engine is suitable for describing the overall system so that control of the throttle valve, the injection valve 9 and the intake and outlet valves 5 , 6 can be implemented optimally for the internal combustion engine.
[0038] If the measured pressure in the intake manifold 4 deviates from the theoretically expected value, then this may point firstly to an incorrectly determined air mass flow into the intake manifold 4 and secondly to a deviating absorption behavior of the cylinder 1 relative to an expected absorption behavior. Where a measured pressure is greater than the theoretically expected value, this means that the air mass flow of the air sucked into the intake manifold 4 is greater than expected on the basis of the flow cross-section of the throttle valve 11 . The increased pressure in the intake manifold 4 can, however, also arise as a result of a deviating absorption behavior, whereby less of the air/fuel mixture is let into the combustion chamber 3 than specified on the basis of the absorption characteristic curve. Since at the same time an adaptation based on the measured pressure can usefully be made either to the flow cross-section of the throttle valve or to the absorption behavior, it may be that an adaptation is made to a system parameter which is not responsible for the deviation in the intake manifold pressure.
[0039] If the system parameter of the flow cross-section is adapted, even though the increased pressure in the intake manifold 4 is caused by a deviating absorption behavior of the cylinder 1 , then the calculated air mass will be too great and the injection quantity increased mistakenly. The increased injection quantity leads to too rich an air/fuel ratio, which can be determined with the aid of the lambda probe. With the lambda probe, a further adaptation relating to the injection quantity is then carried out, the quantity of fuel being reduced in order to obtain the desired air/fuel ratio. Although in this way the model for a working point of the internal combustion engine can be brought into harmony with the measurement values, the incorrect system parameters are adapted which at a different working point will probably not be appropriate. At a different working point, an adaptation has then to be carried out again, which necessitates a certain period of time during which the internal combustion engine will not be functioning optimally.
[0040] If the cause of an increased intake manifold pressure lies in the fact that the absorption behavior of the cylinder 1 is lower than the theoretically expected value, i.e. for a defined valve opening time and valve position a smaller quantity of the air/fuel mixture is let into the combustion chamber 3 , then it would be useful to adapt the absorption behavior of the cylinder 1 with the aid of one or more adaptation values. If, instead, the adaptation value of the flow cross-section is increased, then a further adaptation of the injection quantity based on the measured lambda value causes a change in the adaptation value for the injection quantity. Since applying an adaptation value to the flow cross-section and applying an adaptation value to the injection quantity do not describe the real cause of the deviation in the intake manifold pressure, it is probable that a repeat adaptation of all system parameters will have to be carried out when the working point of the internal combustion engine changes.
[0041] FIG. 2 shows the characteristic curve of the absorption behavior of the cylinder 1 . The absorption characteristic curve is a straight line with an offset value η OFS and a gradient η SLOP . The absorption characteristic curve describes a dependency between the flow of the air/fuel mixture in the cylinder and the pressure in the intake manifold. The offset value η OFS and the gradient η SLOP are parameters which are produced from the respective valve settings of the intake and outlet valves, the rotational speed of the engine and possibly other parameters. When the absorption behavior is adapted, adaptation values can be applied both to the parameters η OFS and/or η SLOP and to the parameters for the valve settings.
[0042] FIG. 3 shows two flow diagrams illustrating the inventive method for adapting the system parameters of flow cross-section, absorption behavior and injection quantity. The adaptation is carried out with the aid of the measured intake manifold pressure and the lambda value of the exhaust gas flowing out of the combustion chamber 3 . The adaptation method is implemented as soon as the internal combustion engine is started. Essentially, two adaptations, namely the adaptation of the injection quantity and the adaptation of the flow cross-section and/or of the absorption behavior, proceed in parallel. The adaptations can also be carried out in succession one after the other.
[0043] FIG. 3 shows two flow diagrams. The first flow diagram shows the regularly running adaptation of the injection quantity in accordance with the lambda value determined in the exhaust pipe 7 . After the internal combustion engine has been started in a step S 1 , a ratio of the air/fuel mixture is calculated initially for example from the rotational speed of the internal combustion engine and from the air mass flow which is to be let into the combustion chamber 3 in order to achieve the desired operating state of the internal combustion engine (step S 2 ). Ideally, the air/fuel ratio is essentially balanced so that the air/fuel mixture is neither too rich nor to lean. If the lambda probe 13 determines in a step S 3 that the mixture is richer than previously calculated, then an adaptation value for the injection quantity is reduced (step S 5 ) so that the quantity of fuel to be injected is reduced. This can take place gradually, i.e. in accordance with a fixed increment or by means of the parameter measured by the lambda probe 13 .
[0044] If it is not ascertained until a step S 4 that the air/fuel mixture is leaner than calculated, then the injected fuel quantity has to be increased by increasing the relevant adaptation value (step S 6 ). The adaptation method for adapting the injection quantity is implemented periodically so that the adaptation value for the injection quantity is after several periods set to a value at which the measured air/fuel ratio matches the calculated air/fuel ratio.
[0045] The second flow diagram in FIG. 3 shows the adaptation of the flow cross-section or of the absorption behavior of the internal combustion engine according to the invention. The sequence of the second flow diagram runs essentially in parallel with the sequence of the first flow diagram.
[0046] After the engine has been started, the system parameters for regulating the internal combustion engine are measured or computationally determined in a step S 11 and the theoretically expected intake manifold pressure in the intake manifold 4 determined from the system parameters. Then, in a step S 12 the pressure in the intake manifold is measured with the aid of the pressure sensor 14 and compared with the calculated intake manifold pressure. If it is established that the intake manifold pressure is greater than calculated, then it is initially assumed that this is caused by a greater flow cross-section at the throttle valve 11 . In this case, the flow cross-section is adjusted upwardly (step S 13 ) so that the calculated air mass flow increases. If the reason for the intake manifold pressure being too high is that the absorption behavior is lower then the expected value and consequently less air/fuel mixture enters the combustion chamber than calculated, the air mass flow is calculated to be too high by the corresponding adaptation value. As a result of too great an air mass flow being calculated, based on the regulation which is designed to preserve a defined air/fuel ratio, the injection quantity of fuel has to be increased in a step S 14 . The raising of the injection quantity then leads to too rich an air/fuel mixture since the calculated air mass is greater than the air mass really present in the intake manifold 4 .
[0047] The lambda adaptation according to the first flow diagram in FIG. 3 then reduces the injection quantity in order to obtain the desired air/fuel ratio.
[0048] If the intake manifold pressure is lower than calculated (step S 15 ), then the adaptation value for the flow cross-section is reduced so that the calculated air mass is reduced and in accordance with the regulation of the internal combustion engine the injection quantity reduced. This leads to the air/fuel ratio being rendered leaner, whereby the injection quantity is increased if the air/fuel ratio is too lean.
[0049] After the adaptation for the flow cross-section has proceeded, a check is carried out to ascertain whether, on the basis of the adaptation values for the injection quantity and the flow cross-section, it can be concluded that a substantial deviation of the real absorption behavior from the ideally expected absorption behavior applies. This is with some probability the case if the adaptation value for the flow cross-section is increased and the adaptation value for the injection quantity is reduced, or vice versa. For a deviation of the adaptation value from a neutral value, defined threshold values are preferably assumed for the percentage deviation or absolute deviation. In this way, a switch can be made, for example, from adaptation of the flow cross-section to adaptation of the absorption behavior of the internal combustion engine if the adaptation value for the flow cross-section is increased by at least a first percentage proportion, e.g. by at least 10%, relative to the neutral value and the adaptation value for the injection quantity is reduced by at least a second percentage proportion, for example also by at least 10%. This also applies if the adaptation value for the flow cross-section is reduced by the first percentage proportion relative to the neutral value and the adaptation value for the injection quantity is increased by the second percentage proportion relative to the corresponding neutral value (step S 18 ). If this is not the case, the process jumps back to step S 11 and the adaptation of the flow cross-section is carried out afresh. If, however, these deviations are identified, in a following step S 19 the adaptation value for the flow cross-section is reset and the adaptation for the absorption behavior of the engine begins. If the measured intake manifold pressure is higher than expected (step S 20 ), then by applying the appropriate values η SLOP and η OFS , the absorption behavior is adapted appropriately (step S 21 ). Alternatively, the adaptation values can also be applied to the corresponding parameters for the valve settings. The adaptation values are chosen such that the calculated absorption behavior is reduced. If the measured intake manifold pressure is lower than expected (step S 22 ), then the adaptation value or adaptation values for the absorption behavior of the internal combustion engine are correspondingly increased (step S 23 ). Essentially, adaptation of the injection quantity, in which a modified adaptation value that is applied to the injection quantity is determined, is simultaneously continued.
[0050] According to one embodiment, it is possible for the resetting of the adaptation value for the flow cross-section to be carried out gradually and to be reset by a defined value in the direction of the neutral value, for example, each time the adaptation method for the absorption behavior of the internal combustion engine is run through. Alternatively, it is also possible to reset the adaptation value for the flow cross-section to the neutral value at a stroke and simultaneously in accordance with a predefined calculation formula computationally to adjust the adaptation value for the absorption behavior of the internal combustion engine. In both cases, an abrupt modification of the system parameters can be avoided so that no large target/actual deviation can occur and an oscillation of the regulation can be avoided. In general, no further deviation from the adaptation of the absorption characteristic curve occurs so that no further adaptation of the flow cross-section is possible. Conditions can, however, be defined (step S 24 ) which make it possible for an adaptation of the flow cross-section to be carried out afresh. Such a condition can, for example, be the lapse of a certain period of time so that it is possible after adapting the absorption characteristic curve to carry out a repeat adaptation of the flow cross-section. This is useful since it can occur that both absorption characteristic curve and flow cross-section reveal deviations and thus have to be corrected.
[0051] The adaptation of the absorption behavior of the internal combustion engine can be effected by adjusting valve control parameters, for example by additional adjustment of the valve overlap or of the intake or outlet valve position.
[0052] The method described stands solely as an example of a possible way of optimizing the adaptation of system parameters in an overall system which is most likely the cause of the deviation between calculated values and the measured values.
[0053] The invention consists generally in the fact that, in regulating an internal combustion engine, several deviations between measurement parameters and expected values or several adaptation values with regard to their magnitude and sign are evaluated and the corresponding system parameters for the adaptation selected such that those most likely to be responsible for the deviation between model and reality are adapted. Here, the criterion can generally be applied that the weighted sum of all adjustments which are necessary for matching modeled parameters and measurement values is minimal. In this process, several different working points of the internal combustion engine are also preferably examined. The criterion can also be applied that the adaptation values for matching modeled parameters and measurement values vary as little as possible across the working points examined.
[0054] Generally speaking, a system parameter is selected for adjustment if several deviations between measurement parameters and expected values or several adaptation values point to a deviation of this system parameter in the same direction. It is not absolutely necessary to adapt the system parameters which are most likely to be causing the model deviation by means of an adaptation method; suitable adjustment values can also be calculated directly and applied to the appropriate system parameter. Care must be taken to ensure that the adaptation values of other system parameters are correspondingly reduced, where applicable, in order to avoid an oscillation of the regulating system. | The invention relates to a method for regulating an internal combustion engine where engine measurement and engine adjustment values are provided, and adaptation values modify the engine parameters, comprising measuring a first engine measurement parameter representative of a first physical engine parameter, measuring a second engine measurement parameter representative of a second physical engine parameter, calculating a first estimation parameter via a first engine parameter, calculating a second estimation parameter via a second engine parameter, determining a first operating mode of the engine regulation method, the first operating mode determined by generating a first adaptation value based on the first engine parameter, generating a second adaptation value based on the second measurement parameter, and comparing the percent difference of the first and second adaptation values to a neutral value of the respective engine parameter, and determining a second operating mode of the engine regulation method, the second operating mode determined by, resetting the second adaptation value for the second system parameter to an original value if the deviation of the percent difference for the first and second adaptation values exceeds a predetermined threshold value. | 5 |
This is a continuation of application Ser. No. 140,509, filed Apr. 15, 1980, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of containers possessing protective coatings for improved impact absorbance and shatter resistance.
2. Description of the Prior Art
Olefin-vinyl ester copolymers possess excellent impact absorbing characteristics which have led to their being investigated for use as container coatings, especially for fragile containers such as glass bottles, to improve resistance to shattering. Ethylene-vinyl acetate copolymers are widely employed as a coating for various substrates and can be applied thereto employing anyone of several known and conventional procedures, e.g., dip coating, powder spraying, electrostatic coating, and the like. However, the tendency of this and many other olefin-vinyl ester copolymer coatings to adhere to each other or exhibit tack has presented a considerable obstacle to the total acceptance of the copolymers in the packaging industry where high, sustained rates of production with minimal disruptions are essential requirements of an economically viable bottle-filling system. U.S. Pat. No. 3,805,985 describes a glass container coated with a uniformly hydrolyzed ethylene-vinyl acetate copolymer. However, uniformly hydrolyzed olefin-vinyl ester copolymers, while resistant to blocking and demonstrating good lubricity characteristics, are at the same time inferior in impact absorbance to the unhydrolyzed resins from which they are prepared.
SUMMARY OF THE INVENTION
In accordance with the present invention, a container is provided with a protective coating having a frosty appearance simultaneously possessing substantially the same degree of impact absorbance and shatter resistance as olefin-vinyl ester copolymer and substantially the same degree of container-to-container lubricity as the corresponding hydrolyzed olefin-vinyl ester copolymer. Following application of an olefin-vinyl ester copolymer coating to a container substrate, the exterior surface of the copolymer is hydrolyzed with the underlying portion of the coating remaining unaffected. Operating in this manner, a coating will be provided which retains mechanical properties virtually identical to those of the coating as originally applied to the container but with substantially improved lubricity characteristics due to the presence of a superficial layer of hydrolyzed resin on the exposed surface thereof. In addition to possessing functionally superior properties compared to a uniformly hydrolyzed olefin-vinyl ester resin coating, the container coating herein can be obtained at lower cost since only a relatively minor percentage of the resin content of the coatings need be hydrolyzed. The surface hydrolyzed EVA coatings are not clear and glossy, but have an unexpected frosty appearance which can be attractive in numerous applications.
The coatings herein can be applied to many different types of substrates, both rigid and flexible, and are especially useful as shatter-resistant protective coatings when applied to glass tubing, glass bottles and other similarly fragile objects. The coatings can be applied to a container in a variety of ways, for example, as a dry powder by fluidized bed, electrostatic fluidized bed, or electrostatic spraying, or as an aqueous or organic dispersion by spraying, followed by exposure of the coated container to an acid or base catalyzed hydrolysis reaction medium, e.g., spraying of such a reaction medium onto the coated container and thereafter passing the container through a steam chest, or immersing the container in the reaction medium.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The polyolefin coatings which are suitable for use herein can be prepared from any of the known and conventional olefin-vinyl acetate copolymer powders which are or can be employed in coating applications. Thus, for example, the olefin-vinyl ester resin powders can be selected from copolymers of one or more olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and the like, and one or more vinyl esters such as vinyl formate, vinyl acetate, vinyl proprionate, vinyl butyrate, vinyl isobutyrate, vinyl laurate, and the like. In general, the copolymers can be prepared with from about 30 to about 95, and preferably, from about 60 to about 90, weight percent olefin and from about 70 to about 5, and preferably from about 40 to about 10, weight percent vinyl ester. In addition to the foregoing, the copolymers can be prepared with small amounts, e.g., up to about 10 weight percent of the entire monomer mixture, of at least one other ethylenically unsaturated monomer copolymerizable with olefin and vinyl ester. Ethylene-vinyl acetate copolymers are especially preferred due to their widespread acceptance for food packaging applications, their relatively low cost and their ready commercial availability. Such powders can be spherical or irregularly shaped and can have an average particle size of from less than 20 microns to greater than 1,200 microns.
Optionally, the coating resins of this invention can contain one or more slip agents, free-flow agents, fillers, dyes, pigments, and the like, in the customary amounts.
The olefin-vinyl ester resin powders can be applied to rigid surface objects such as glass containers by any known technique, however, it is preferred to use any one of several electrostatic coating techniques in current use. This includes electrostatic spray and cloud coating methods.
In the electrostatic spray coating method, coating powder and air are introduced into a high voltage spray "gun". As the powder particles are ejected from the gun, they pass a negative electrode. The container to be coated is grounded, and is therefore positively charged. As the negatively charged powder particles approach the positively charged container, they are attracted to the surfaces of the container and adhere tenaciously thereto. As the coating forms, the substrate becomes insulated and the powder in the applied coating repels excess powder. The uniform coating that results must then be heated to the fusion temperature of the olefin-vinyl ester copolymer to complete the process. The thickness of the film that can be applied can vary from 1.5 mils to approximately 15 mls and even higher, depending on the temperature of the part, electrical potential difference and duration of spraying time. Higher substrate temperatures allow the deposition of thicker coatings.
In the electrostatic cloud coating method, a low volume of dry air or gas, passed through a porous plate, suspends and fluidizes the powder. Upon application of high voltage to an electrode grid in the bottom of the bed, the powder becomes charged and is dispersed into a fine cloud within the top portion of the bed. The powder is then attracted to the grounded container which has been passed through the cloud. A container coated by this method will be coated evenly over its entire surface due to the self-insulating effect of the powder. The "Pherostatic" coating method (Electrostatic Equipment Corporation, New Haven, Connecticut) which is a variation of the aforedescribed fluidized bed coating method involves the use of two electrostatic beds which are placed next to each other with a powder collector below and common to both ends of the beds. A grounded container is inserted between the beds so that the charged plastic particles that overflow, creating a cloud in between the beds, will be attracted to the grounded object.
Fluidized bed coating can also be used. This method is analogous to the dipping process used with liquid coatings. In using this method the powdered coating resin is expanded by passing an air stream upwardly through it. The container to be coated is preheated to a temperature above the melting point of the powder and then lowered into the expanded bed of material. Each portion of the heated container that touches the powder causes the powder to melt and adhere. After the container is removed from the fluidized bed, it is post heated to produce the desired flow and coating properties.
Following application of the olefin-vinyl ester coating to the exterior surface of the container, the coating is surface hydrolyzed to a desired extent employing an acid or based catalyzed hydrolysis medium. The extent of hydrolysis can be regulated by adjusting the period of exposure of the coating to the hydrolysis medium, altering the concentration of acid or base in the medium and/or adjusting the temperature at which hydrolysis is carried out. In general, only as much surface hydrolysis should be obtained which results in a significant improvement in container-to-container lubricity but does not appreciably compromise the impact absorbing properties of the olefin-vinyl ester coating prior to hydrolysis. The optimum degree of hydrolysis for a given coating can be readily determined employing simple and routine methods. Surface hydrolysis to a depth of about 30 percent, and preferably to a depth of about 10 percent of the average thickness of the coating is effective in most cases. Methods of hydrolyzing olefin vinyl ester resins are well known in the art and do not in themselves constitute a part of this invention. The container coatings herein can be readily surface-hydrolyzed by spraying a quantity of hydrolysis reaction medium, e.g., a dilute aqueous solution of an alkali metal hydroxide such as sodium hydroxide, on to the coated container and thereafter treating the container with steam for the desired degree of surface hydrolysis. Alternatively, the coated container can be immersed in such a hydrolysis medium at elevated temperature until the requisite level of surface hydrolysis is achieved. Prior to such immersion, it is frequently advantageous to preheat the coated container, e.g., to a temperature of from about 150° to about 500° F., to reduce tack at a faster rate in the surface hydrolyzed olefin-vinyl ester resin coatings.
Examples 1 to 8 which are summarized below are illustrative of the invention employing three different ethylene-vinyl acetate copolymer coatings designated A, B and C, and employing aqueous solutions of sodium hydroxide heated to 185°±5° F. as the hydrolysis media. As the results indicate, differences in various process parameters will influence the effect obtained in varying degrees. Preheating the coated container prior to immersion in the hydrolysis medium was observed to have a particularly beneficial influence on the elimination of tack. Slip Angle is a conventional measurement indicative of container-to-container lubricity and represents the angle at which the top container of a three-container pyramid begins to slip off the bottom two containers which are restrained from moving.
__________________________________________________________________________ Sodium Ethylene- Hydroxide Coated Container Vinyl Concentra- PreheatExample Acetate tion, % Tempera- Time, Immersion Slip Angle,No. Copolymer weight ture of Minutes Time, minutes degrees Results__________________________________________________________________________ A.sup.1 40 420 2 5 35-38 Cloudy/frosty; reduced tack A 40 420 2 2 28-35 Cloudy/frosty; reduced tack A 40 420 2 1 Slighty cloudy; non-uniform B.sup.2 50 185 ± 5 15 15 ≧45 Cloudy/frosty; less tack B 50 185 ± 5 15 10 Slighty cloudy/frost; less tack B 50 185 ± 5 15 5 Very slighty cloudy/frosty; less tack A 40 300 3 15 Cloudy/frosty; more uniform than Example 3 C.sup.3 40 420 3 2 Very slight haze and very slight reduction in__________________________________________________________________________ tack .sup.1 Approximately 9 weight percent copolymerized vinyl acetate. .sup.2 Approximately 19 weight percent copolymerized vinyl acetate. .sup.3 Approximately 30% weight percent copolymerized vinyl acetate. | A container is provided with a coating having a frosty appearance comprising an olefin-vinyl ester copolymer the exterior surface of which is hydrolyzed following application of the coating to the exterior surface container. Surface hydrolysis of the olefin-vinyl ester coating significantly improves container-to-container lubricity without appreciably affecting the mechanical properties of the coating. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates to the in vitro culture of animal cells, and more particularly to a spin filter for removing substantially cell-free culture medium from a perfusion-type suspension cell culture system.
The in vitro culture of animal cells, particularly for purposes of recovering proteins either normally secreted by such cells or secreted by such cells by virtue of manipulation of their genetic machinery, has assumed increasingly greater prominence as a consequence of the increasing need for large quantities of proteins for therapeutic, diagnostic and investigative purposes, and the recognition that animal cells (per se, or as a hybrid partner, or as a host for an exogeneous gene) offer the best source of proteins which are the same as or closely similar to those actually employed by animals (e.g., humans) in vivo in carrying out regulatory, immune response, and other like functions.
Despite the recognized advantages of, and needs for, in vitro animal cell culture, the culture of cells outside the animal body is a difficult proposition at best, made even more difficult by the present-day demand that such processes be carried out efficiently and economically so as to achieve ultimate protein products which are not unreasonably expensive.
Among the known in vitro animal cell culture devices and systems exhibiting potential for mass production of cell-secreted proteins are the perfused fermenters, i.e., culture vessels in which animal cells are cultured in suspension in a culture medium which is agitated to promote homogeneity, and in which culture fluid is continuously or intermittently drawn off and replaced with a corresponding volume of fresh culture medium. Such suspension culture systems can be employed to culture anchorage-dependent cells by arranging such cells on suitable substrate materials (microcarrier particles), and are of course also useful for culture of cells which do not require attachment to surfaces in order to grow and proliferate.
Among the more significant problems related to perfused suspension culture systems is the difficulty of periodic or continuous removal of culture fluid from the vessel without at the same time removing cells suspended in the fluid. Numerous proposals and devices have been postulated and/or constructed to alleviate this problem, generally involving some means of filtration to separate cells from medium as medium is withdrawn from the vessel. One device which has achieved a degree of commercial acceptance is a so-called "spin filter", i.e., a rotating cage-like hollow cylinder immersed in the cell/medium suspension in the vessel and designed to exclude cells, but not liquid, from entering its interior space from which medium will be withdrawn from the system via an appropriate effluent overflow tube in association therewith. Typically, the spin filter comprises a core liquid-impermeable cylinder surrounded by a concentric liquid-permeable cylindrical mesh or screen, such that an annular cylindrical space exists between the outer surface of the core cylinder and the inner surface of the surrounding concentric cylindrical mesh to define the area from which cell-free medium can be withdrawn from the suspension culture vessel. The combined core and concentric screen rotate as a unit, either by independent rotation means or by being affixed to the shaft which drives the culture vessel impeller for agitating the suspension of cells and medium.
In the development of filters for attaining cell separation before withdrawal of medium, considerable attention has been devoted to the appropriate sizing of the pores or apertures in filtering surface. Clearly one way to insure that medium but not cells pass through the filter into the interior annular region for removal from the vessel is to utilize filter materials having aperture sizes smaller than the cell size. For cells grown on microcarriers or for cells which grow as aggregates in suspension, such criterion generally permits relatively large apertures which are less prone to clogging or fouling and which are readily permeable to the culture fluid. However, for cells (e.g., hybridomas) which grow as single cells in suspensions, extremely small apertures are needed in order to exclude cells on the basis of size alone. Depending upon the particular aperture size, perfusion rate and cell density, use of such small filter apertures will lead to extensive clogging and fouling of the filter surfaces within a very short time, e.g., within about one week for systems involving aperture sizes of less than about ten (10) microns, cell densities of greater than about 10 6 cells/ml. and perfusion rates of greater than about 0.5 volumes of medium perfused per reactor volume per day. As a compromise solution, the aperture size is generally chosen to be larger than the cell size and as a consequence, complete retention of cells in the culture vessel as medium is withdrawn is not possible. Moreover, even operation in this manner does not completely eliminate fouling and clogging which limits the useful life of the spin filter and requires that the culturation be ceased to regenerate or replace the filter.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a spin filter for the suspension culture of cells, particularly of cells which generally grow as single cells in suspension.
Another object of the invention is the provision of a spin filter which enables the withdrawal of substantially cell-free medium from the suspension culture vessel while at the same time being less susceptible to clogging and fouling such that it can remain in operation for extended periods of time at reasonably high cell densities and perfusion rates, thereby enabling suspension culture of cells to the high densities required for commercial-scale production of cell-secreted proteins.
These and other objects as will be apparent are provided by an impeller-driven suspension culture apparatus for the in vitro perfusion suspension culture of animal cells suspended in a liquid culture medium, the apparatus comprising a culture vessel; within the vessel, an impeller rotatable in a given direction to promote the axial flow of cells and medium within the vessel; an inlet for addition to the vessel of culture medium; within the vessel, a spin filter which is rotatable independent of the vessel impeller and in a rotational direction opposite thereto, the spin filter comprising a vertically-oriented hollow receptacle made of porous liquid-permeable material, such that at least a portion of the interior of the hollow receptacle defines a substantially cell-free liquid withdrawal space for receiving culture medium from the culture vessel which has passed into the space across the porous liquid-permeable material of the receptacle; liquid withdrawal means arranged in the liquid withdrawal space for withdrawing medium from the space and from the culture vessel; and one or more vertically-oriented baffles arranged in the liquid withdrawal space. The average pore size of the porous liquid-permeable material making up the surfaces of the hollow receptacle is such that it is sufficient to substantially exclude materials greater than about 8 to 10 microns in size, and in operation the spin filter is at least periodically, and preferably continuously, rotated in a rotational direction opposite to that of the vessel impeller.
In the preferred embodiments of the invention, the spin filter comprises a vertically-oriented liquid-impermeable core which is surrounded by, yet axially spaced from, the hollow receptacle so that the liquid withdrawal space is defined by the area between the core and the receptacle, and the baffles are arranged in that so-defined space. In the most preferred embodiment, the spin filter is cylindrical, i.e., having a cylindrical liquid-impermeable core, a surrounding hollow cylinder of the porous liquid-permeable material concentric thereabout, and a liquid withdrawal space which is defined by the annular area between the concentric core and hollow cylinder.
The present invention is predicated upon investigation of the phenomena associated with the fouling and clogging of the filter surfaces of spin filters, and discovery of effects which produce fouling and clogging. In particular, it has been found that fouling of the filter by cells generally occurs by reason of cells passing through the filter pores and then accumulating on the inner-facing filter surfaces. In typical spin filter operation, the liquid in the liquid withdrawal space rotates at the same speed as the filter itself and, as a consequence, there is no surface sweeping effect to prevent cells from accumulating on the inner-facing filter surface (via natural attachment and/or centrifugal force). At the same time, another contributor to fouling is protein debris, which preferentially tends to associate with the outer-facing filter surfaces.
As a consequence of the foregoing observations and studies, the spin filter of the present invention takes into account features and modes of operation designed to counteract the normal fouling effects. Thus, the pore or aperture size of the liquid-permeable material of the filter is chosen to be small so as to reduce the tendency for cells to pass through the apertures and collect on the inner-facing filter surfaces. In addition, to deal with those cells which do pass through the filter into the liquid withdrawal space, one or more stationary vertically-oriented baffles is arranged in the liquid withdrawal space (e.g., associated with the liquid overflow tube therein and/or suspended in the space from separate means emanating, e.g., from a cover plate over the vessel) to break down liquid motion in the liquid withdrawal space and thus substantially prevent cells from collecting on the inner-facing filter surfaces. The baffle or baffles are referred to as stationary baffles in the sense that they are independent of the spin filter surfaces per se, i.e., they do not rotate with the spin filter as it rotates. Finally, for minimizing the tendency of protein debris to collect on the outer-facing filter surfaces, the spin filter is adapted to rotate in a direction opposite that of the impeller which agitates the vessel contents.
By virtue of the construction and operation of the spin filter according to the present invention, cell retention rates of greater than 90% have been attained in single cell suspension culture systems with useful filter operating life (i.e., before fouling) of over 3 weeks, at cell densities of about 8×10 6 to 2×10 7 cells/ml. and volumetric perfusion rates of 1 to 5.5 liters per liter reactor per day.
The invention is further described with reference to the drawings and the detailed description provided hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a suspension culture vessel employing a spin filter in accordance with the invention.
FIGS. 2 and 3 represent graphs of data collected in a comparison of the spin filter system according to the invention and a commercially-available spin filter system.
DETAILED DESCRIPTION OF THE INVENTION
In the preferred embodiment of the invention, and with reference to FIG. 1, there is shown a suspension culture vessel 100, generally constructed of biologically compatible sterilizable material such as glass, but most preferably stainless steel. Within the culture vessel is a draught tube 101 and a motor-drive impeller 102 which generally directs flow vertically upward through the draught tube for overflow at its top region, establishing an overall axial mixing of cells and the medium in which they are suspended and preventing cell-sedimentation. The general operating liquid level in the vessel is shown as 103.
Arranged within the culture vessel 100 is a spin filter, generally designated as 104, which is suspended in the liquid suspension from a top cover plate 105 over the vessel, and which is affixed to rotation drive means 107 which are independent of the drive means for impeller 102 and which are capable of rotating the spin filter 104 in a rotational direction opposite that of the impeller 102.
The spin filter 104 consists of an inner core cylinder 108 which is liquid-impermeable. The core cylinder 108 may be solid or hollow and, if the latter, is closed at its top and bottom, and is preferably constructed of stainless steel or other like material. Surrounding core cylinder 108 is a concentric hollow cylindrical shell 109 having a larger cross-sectional diameter than that of the core cylinder such that an annular cylindrical space 110 exists therebetween. The hollow cylindrical shell 109 is composed of porous liquid-permeable material, preferably a stainless steel mesh, having apertures of from about 5 to 10 microns so as at least nominally capable of excluding solid particles having diameters larger than about 10 microns. The core cylinder 108 and concentric hollow cylinder 109 are affixed in any suitable manner (e.g., at their bases) for rotation in tandem, so long as the annular space 110 remain open at the top. As shown, the annular space 110 at the bottom of the spin filter is completely closed, although it is possible to have the closure be by way of the mesh materials, i.e., such that liquid can pass therethrough. The important consideration is that any liquid in annular space 110 have arrived there by passing across the porous liquid-permeable material from which hollow cylindrical shell 109 is made.
Arranged in the upper region of the annular space 110 is a liquid level tube 111 through which substantially cell-free culture medium in annular space 110 will rise and exit from the culture vessel in response to an increase in liquid level such as brought about by feed of fresh or replenished culture medium through feed port 112.
Arranged in the annular space 110, preferably substantially throughout its vertical length, is a stationary baffle or vortex breaker 113. For ease of construction, baffle 113 can be associated with level tube 111, but it is also possible to suspend the baffle independently from cover plate 105 or in any other suitable way which maintains its generally stationary character relative to the rotation of the spin filter device. Although one baffle is shown in the FIG. 1, multiple baffles may be employed.
In continuous or semi-continuous perfusion operation, a volume of culture medium is fed into the culture vessel via inlet tube 112. The contents of the vessel are axially stirred by rotation of impeller 102, and spin filter 104 will be rotated in the opposite direction. Cell-containing medium in contact with filter shell 109 will pass substantially cell-free into annular space 110 by reason of the small pore size of the filter material, and is withdrawn from the annular space as the liquid level 103 in the vessel rises above the bottom of level tube 111. The stationary baffle 113 serves to disrupt liquid flow in the rotating annular space 110 so as to minimize the tendency of any cells which have passed through filter 109 to collect on the inner-facing filter surfaces. At the same time, the rotation of the spin filter opposite to that of impeller 102 reduces the tendency of protein debris to collect on and foul the outer-facing filter surfaces.
As a consequence of the invention, it is possible to employ filter pore or aperture sizes which inherently insure that a large majority of the cells in suspension will be excluded from the annular space thereby substantially increasing the ability to remove essentially cell-free medium from the culture vessel. At the same time, however, the pronounced tendency of such small filter pores to clog and foul is substantially minimized by virtue of the baffle arrangement and the counterrotation of the spin filter.
The advantages of the present invention can be seen in the graphically-presented data of FIGS. 2 and 3. In these tests, otherwise identical suspension culture perfusion vessels were operated side-by-side in culture of cells which grow as single cells in suspension. In the control reactor (data shown in FIG. 3), the spin filter (cylindrical screen surrounding solid core) had an 8 micron pore size and was rotated at the same rate and in the same direction as the vessel impeller. In the reactor according to the invention (data shown in FIG. 2), the spin filter was identical in all respects except for the presence of a vertical baffle suspended from the vessel cover into the annular space between the spin filter core and surrounding cylindrical screen, and the rotation of the spin filter, while at the same rate as in the control, was in a direction opposite that of the vessel impeller.
In the system according to the invention, the perfusion rate was gradually increased over time to as high as 5.5 liters of medium/liters of reactor/day, leading to attainment of high viable cell densities, i.e., operating the system at commercially-desirable conditions yet most susceptible to filter clogging. In contrast, perfusion rates for the control reactor were maintained at relatively low levels of about 0.5 liters/liters/day and consequent low viable cell densities, i.e., conditions designed not to challenge the spin filter capabilities too drastically. Nevertheless, within one week the spin filter in the control reactor clogged, while that in the system according to the invention operated about thirty (30) days without significant clogging even under the conditions of high perfusion rate/high cell density.
Although the invention has been described with reference to particular preferred features and exemplary parameters, these are intended to illustrate rather than limit the scope of the invention, as defined in the appended claims. | A spin filter for removing substantially cell-free medium from a stirred suspension culture vessel, wherein a stationary baffle is arranged in the interior space of the spin filter to disrupt liquid flow therein and minimize the tendency of cells to collect on and foul the inner-facing filter surfaces, the filter surface being sized to substantially exclude materials greater than about 8 to 10 microns, and the spin filter being rotatable independent of, and in a rotational direction opposite to, the vessel stirring device. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 12/751,520, filed Mar. 31, 2010, now U.S. Pat. No. 8,573,333,issued on Nov. 5, 2013, which is a utility conversion of U.S. Provisional Patent Application Ser. No. 61/165,382, filed Mar. 31, 2009, for “Methods For Bonding Preformed Cutting Tables to Cutting Element Substrates and Cutting Elements Formed by Such Processes,” the disclosure of each of which is incorporated in this application in its entirety by this reference.
FIELD
The present disclosure relates generally to cutting elements, or cutters, for use with earth-boring drill bits and, more specifically, to cutting elements that include thermally stable, preformed superabrasive cutting tables adhered to substrates with diamond. The present disclosure also relates to methods for manufacturing such cutting elements, as well as to earth-boring drill bits that include such cutting elements.
BACKGROUND
Conventional polycrystalline diamond compact (PDC) cutting elements include a cutting table and a substrate. The substrate conventionally comprises a metal material, such as tungsten carbide, to enable robust coupling of the PDC cutting elements to a bit body. The cutting table typically includes randomly oriented, mutually bonded diamond (or, sometimes, cubic boron nitride (CBN)) particles that have also been adhered to the substrate on which the cutting table is formed, under extremely high-temperature, high-pressure (HTHP) conditions. Cobalt binders, also known as catalysts, have been widely used to initiate bonding of superabrasive particles to one another and to the substrates. Although the use of cobalt in PDC cutting elements has been widespread, PDC cutting elements having cutting tables that include cobalt binders are not thermally stable at the typically high operating temperatures to which the cutting elements are subjected due to the greater coefficient of thermal expansion of the cobalt relative to the superabrasive particles and, further, because the presence of cobalt tends to initiate back-graphitization of the diamond in the cutting table when a temperature above about 750° C. is reached. As a result, the presence of the cobalt results in premature wearing of and damage to the cutting table.
A number of different approaches have been taken to enhance the thermal stability of polycrystalline diamond and CBN cutting tables. One type of thermally stable cutting table that has been developed includes polycrystalline diamond sintered with a carbonate binder, such as a Mg, Ca, Sr, or Ba carbonate binder. The use of a carbonate binder increases the pressure and/or temperature required to actually bind diamond particles to one another, however. Consequently, the diameters of PDC cutting elements that include carbonate binders lack an integral carbide support or substrate and are typically much smaller than the diameters of PDC cutting elements that are manufactured with cobalt.
Another type of thermally stable cutting table is a PDC from which the cobalt binder has been removed, such as by acid leaching or electrolytic removal. Such cutting elements have a tendency to be somewhat fragile, however, due to their lack of an integral carbide support or substrate and, in part, due to the removal of substantially all of the cobalt binder, which may result in a cutting table with a relatively low diamond density. Consequently, the practical size of a cutting table from which the cobalt may be effectively removed is limited.
Yet another type of thermally stable cutting table is similar to that described in the preceding paragraph, but the pores resulting from removal of the cobalt have been filled with silicon and/or silicon carbide. Examples of this type of cutting element are described in U.S. Pat. Nos. 4,151,686 and 4,793,828. Such cutting tables are more robust than those from which the cobalt has merely leached, but the silicon precludes easy attachment of the cutting table to a supporting substrate.
SUMMARY
The present disclosure includes embodiments of methods for adhering thermally stable diamond cutting tables to cutting element substrates. As used herein, the phrase “thermally stable” includes polycrystalline diamond cutting tables in which abrasive particles (e.g., diamond crystals, etc.) are secured to each other with carbonate binders, as well as cutting tables that consist essentially of diamond, such as cutting tables from which the cobalt has been removed, with or without a silicon or silicon carbide backfill, or that are formed by chemical vapor deposition (CVD) processes.
Some embodiments of such methods include preparation of the surface of a substrate to which a cutting table is to be bound before the cutting table is secured to that surface. In specific embodiments, preparation of the surface of the substrate may include removal of one or more contaminants or materials from the surface that may weaken or otherwise interfere with optimal bonding of the cutting table to the surface. In other specific embodiments, a substrate surface may be prepared to receive a cutting table by increasing a porosity or an area of the surface.
In such methods, preformed cutting tables, which are also referred to herein as “wafers,” are secured, under HTHP conditions, to substrates (e.g., tungsten carbide, etc.) with an intermediate layer of diamond grit. In some embodiments, a powder, particles, or a thin element (e.g., foil, etc.) comprising cobalt or another suitable binder may be used with the diamond grit. In other embodiments, cobalt or another suitable binder material that is present (e.g., as part of a binder, etc.) in the substrate may be caused to sweep into the cutting table as heat and pressure are applied to the cutting table. In further embodiments, a preformed diamond wafer formed by a CVD process may be disposed on a surface of a conventional PDC cutting table previously formed on a substrate. The CVD wafer may then be bonded to the PDC cutting table under HTHP conditions.
The present disclosure also includes various embodiments of cutting elements. One embodiment of a cutting element according to the present disclosure includes a substrate, a thermally stable cutting table and an adhesion layer therebetween. The adhesion layer includes diamond particles bonded to the diamonds of the thermally stable cutting table and to the substrate. In addition to diamond, the adhesion layer may include cobalt. The substrate may comprise a cemented carbide, such as tungsten carbide with a suitable binder, such as cobalt. In another embodiment, a preformed cutting table comprising CVD diamond and bonded to a PDC layer comprising cobalt under HTHP conditions is carried by a cemented carbide substrate.
Other features and aspects, as well as advantages, of embodiments of the present disclosure will become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIGS. 1 and 1A illustrate an embodiment of a process for manufacturing PDC cutting elements from preformed cutting tables, with a specific embodiment of preformed cutting table being shown;
FIG. 1B depicts another specific embodiment of a preformed cutting table that may be used to manufacture a PDC cutting element in accordance with various embodiments of teachings of the present disclosure;
FIG. 2 is a carbon phase diagram;
FIG. 3 depicts a PDC cutting element that includes a substrate, a preformed cutting table, and a diamond adhesion layer between the substrate and the preformed cutting table;
FIGS. 4 and 4A depict another embodiment of a process for manufacturing cutting elements that include preformed wafers that consist of diamond;
FIG. 5 illustrates an embodiment of a cutting element that includes a substrate, a PDC cutting table, and a wafer that consists of diamond atop the PDC cutting table; and
FIG. 6 shows an embodiment of an earth-boring rotary drill bit including at least one PDC cutting element that incorporates teachings of the present disclosure.
DETAILED DESCRIPTION
With reference to FIG. 1 , an embodiment of a process for securing a preformed cutting table 20 to a substrate 30 is illustrated. In that process, at least one “cutter set,” which includes a substrate 30 and its corresponding preformed cutting table 20 , is assembled.
In the method of FIGS. 1 and 1A , at least one substrate 30 is introduced into a canister assembly, or synthesis cell assembly 50 , formed from a refractory metal or other material that will withstand and substantially maintain its integrity (e.g., shape and dimensions) when subjected to HTHP processing. Each substrate 30 may comprise a cemented carbide (e.g., tungsten carbide) substrate for a PDC cutting element, or any other material that is known to be useful as a substrate for PDC cutting elements. In some embodiments, substrate 30 may include a binder material, such as cobalt.
Particles 40 of diamond grit are placed on substrate 30 . More specifically, particles 40 are placed on a surface 32 to which a preformed cutting table 20 is to be secured. Particles 40 may be placed on surface 32 alone or with a fine powder or particles 42 of a suitable, known binder material, such as cobalt, another Group VIII metal, such as nickel or iron, or alloys including these materials (e.g., Ni/Co, Co/Mn, Co/Ti, Co/Ni/V, Co/Ni, Fe/Co, Fe/Mn, Fe/Ni, Fe (Ni.Cr), Fe/Si 2 , Ni/Mn, Ni/Cr, etc.).
Surface 32 may be processed to enhance subsequent adhesion of a preformed cutting table 20 thereto. Such processing of surface 32 may, in some embodiments, include removal of one or more contaminants or materials that may weaken or otherwise interfere with optimal bonding of cutting table 20 to surface 32 . In specific embodiments, metal carbonate binder, silicon, and/or silicon carbide may be removed from surface 32 of substrate 30 , as these materials may inhibit diamond-to-diamond intergrowth, which is desirable for adhering preformed cutting table 20 to surface 32 of substrate 30 . The removal of such materials may be effected substantially at surface 32 . In such embodiments, one or more materials may be removed to a depth, from surface 32 into substrate 30 , that is about the same as a dimension of a diamond particle of preformed cutting table 20 , or to a depth of about one micron to about ten microns. In other embodiments, the removal of undesirable materials may extend beyond surface 32 , and into substrate 30 . Such preparation, in even more specific embodiments, may include leaching of one or more materials from the surface of the substrate.
In other embodiments, an area of surface 32 of substrate 30 may be increased. Chemical, electrical, and/or mechanical processes may, in some embodiments, be used to increase the area of surface 32 by removing material from surface 32 . Specific embodiments of techniques for increasing the area of surface 32 include, but are not limited to, laser ablation of surface 32 , blasting surface 32 with abrasive material, and exposing surface 32 to chemically etchants.
The removal of such materials may, in some embodiments, enable cobalt or another binder to penetrate into substrate 30 to facilitate the bonding of preformed cutting table 20 to surface 32 .
A base surface 22 of preformed cutting table 20 is placed over particles 40 on surface 32 of substrate 30 . Base surface 22 of preformed cutting table 20 is of a complementary topography to the topography of surface 32 of substrate 30 . Preformed cutting table 20 may be substantially free of metallic binder.
Without limiting the scope of the present disclosure, preformed cutting table 20 , in one embodiment, may comprise a PDC with abrasive particles that are bound together with a carbonate (e.g., calcium carbonate, a metallic carbonate (e.g., magnesium carbonate (MgCO 3 ), barium carbonate (BaCO 3 ), strontium carbonate (SrCO 3 ), etc.) binder, etc.). Despite the extremely high pressure and extremely high temperature that are required to fabricate PDCs that include calcium carbonate binders, as this type of PDC is fabricated without a substrate (i.e., is free-standing), it may be formed with standard cutting table dimensions (e.g., diameter and thickness) in a suitable HPHT apparatus, as known in the art.
In another embodiment, depicted by FIG. 1B , a preformed cutting table 20 ′ may comprise a PDC having a face portion 27 ′ and a base portion 23 ′. Face portion 27 ′ of preformed cutting table 20 ′ is adjacent to and includes a cutting surface 26 ′, which may be filled with silicon and/or silicon carbide. Base portion 23 ′ of preformed cutting table 20 ′ is adjacent to and includes a base surface 22 ′, which consists essentially of diamond. Such an embodiment of preformed cutting element may be manufactured by removing (e.g., by leaching, electrolytic processes, etc.) cobalt or other binder material (e.g., another Group VIII metal, such as nickel or iron, or alloys including these materials, such as Ni/Co, Co/Mn, Co/Ti, Co/Ni/V, Co/Ni, Fe/Co, Fe/Mn, Fe/Ni, Fe (Ni.Cr), Fe/Si 2 , Ni/Mn, and Ni/Cr) from face portion 27 ′ without leaching binder material from base portion 23 ′. This may be accomplished, for example, by preventing exposure of base portion 23 ′ to leaching conditions and limiting the duration of the leaching conditions. Silicon or silicon carbide is then introduced into the pores that result from the leaching process, such as by the processes described in U.S. Pat. Nos. 4,151,686 and 4,793,828, the entire disclosures of both of which are hereby incorporated herein by this reference. Thereafter, binder material may be leached from base portion 23 ′, leaving pores therein or the binder material may remain. The porous base surface 22 ′ is placed adjacent the surface 32 of substrate 30 ( FIGS. 1 and 1A ).
With returned reference to FIGS. 1 and 1A , if desired, one or more other cutter sets 12 including a preformed cutting table 20 , a quantity of diamond grit particles 40 (and, optionally, binder material powder or particles 42 ), and a substrate 30 may then be introduced into synthesis cell assembly 50 so that a plurality of cutting elements may be manufactured with a single HTHP process. In embodiments where multiple cutter sets 12 are introduced into a single synthesis cell assembly 50 , the order of components of each cutter set 12 may be reversed from the order of components of each adjacent cutter set 12 . The cutter sets 12 that are located at ends 52 and 54 of a synthesis cell assembly 50 may be arranged with substrates 30 at ends 52 and 54 , or as the outermost elements, to minimize impact upon and the potential for damage to the expensive preformed cutting tables 20 .
Once each cutter set 12 has been assembled within synthesis cell assembly 50 , the contents of synthesis cell assembly 50 may be subjected to known HTHP processes. The temperature and pressure of such processes are sufficient to cause particles 40 (and, optionally, any binder material powder or particles 42 ) to bind each preformed cutting table 20 within synthesis cell assembly 50 to its corresponding substrate 30 . In some embodiments, the combination of temperature and pressure that are employed in the HTHP process are within the so-called “diamond stable” phase of carbon. A carbon phase diagram, which illustrates the various phases of carbon, including the diamond stable phase D, and the temperatures and pressures at which such phases occur, is provided as FIG. 2 .
An embodiment of a PDC cutting element 10 resulting from such processing is shown in FIG. 3 . PDC cutting element 10 includes substrate 30 , a binder layer 45 , and preformed cutting table 20 . Binder layer 45 secures preformed cutting table 20 to substrate 30 , and may be bonded to preformed cutting table 20 and integrated into the material of substrate 30 at surface 32 (see FIGS. 1 and 1A ). In some embodiments, binder layer 45 consists of diamond (e.g., polycrystalline diamond (PCD)). In other embodiments, binder layer 45 consists essentially of diamond. Other embodiments of binder layer 45 include diamond and lesser amounts of a suitable binder material.
In another embodiment of a method encompassed by the present disclosure, which is shown in FIGS. 4 and 4A , at least one cutting element 110 that includes a substrate 30 with a PDC table 120 already secured thereto is introduced into a synthesis cell assembly 50 .
A base surface 142 of preformed wafer 140 , which may consist essentially of or consist entirely of diamond that has been deposited by known chemical vapor deposition (CVD) processes, is placed over a surface 122 of PDC table 120 . Base surface 142 of preformed wafer 140 is of a complementary topography to the topography of surface 122 of PDC table 120 .
As described in reference to the embodiment shown in FIGS. 1 and 1A , one or more other cutter sets 112 including a preformed wafer 140 and a cutting element 110 may be introduced into synthesis cell assembly 50 so that a plurality of cutting elements 110 may be manufactured with a single HTHP process. Once each cutter set 112 has been assembled within synthesis cell assembly 50 , the contents of synthesis cell assembly 50 may be subjected to known HTHP processes, as described in reference to FIGS. 1 and 1A .
An embodiment of a cutting element 10 ′ resulting from such processing is shown in FIG. 5 . Cutting element 10 ′ includes substrate 30 , a PDC table 120 , and a performed wafer 140 that consists essentially of, or consists of, diamond. Base surface 142 of preformed wafer 140 may be secured to surface 122 of PDC table 120 by diamond-to-diamond bonding that occurs during the HTHP process, in which diamond from preformed wafer 140 is bonded with diamond-to-diamond bonding, to diamond crystals of PDC table 120 . Although the resulting structure may include cobalt or another binder material that may, if it were present on the face of preformed wafer 140 , compromise thermal stability, its presence beneath preformed wafer 140 during use of cutting element 10 ′ is at a location which is not subjected to temperatures that are known to be problematic for cutting tables that include cobalt binders.
Turning now to FIG. 6 , an embodiment of a rotary type, earth-boring drill bit 60 of the present disclosure is shown. Among other features that are known in the art, bit 60 includes at least one cutter pocket 62 . A cutting element 10 , 10 ′ according to an embodiment of the present disclosure is received within cutter pocket 62 , with substrate 30 (see FIG. 1 ) bonded or otherwise secured to the material of bit 60 . As used herein, the term “earth-boring drill bit” includes without limitation conventional rotary fixed cutter, or “drag” bits, fixed cutter core bits, eccentric bits, bicenter bits, reamer wings, underreamers, roller cone bits, and hybrid bits including both fixed and movable cutting structures, as well as other earth-boring tools configured with cutting structures according to embodiments of the disclosure.
Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present disclosure, but merely as providing illustrations of some embodiments. Similarly, other embodiments of the disclosure may be devised which do not exceed the scope of the present disclosure. Features from different embodiments may be employed in combination. The scope of specifically claimed embodiments encompassed by this disclosure is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions and modifications to the embodiments disclosed herein which fall within the meaning and scope of the claims are to be embraced thereby. | A cutting element for an earth-boring drill bit may include a thermally stable cutting table comprising a polycrystalline diamond material. The polycrystalline diamond material may consist essentially of a matrix of diamond particles bonded to one another and a silicon, silicon carbide, or silicon and silicon carbide material located within interstitial spaces among interbonded diamond particles of the matrix of diamond particles. The cutting table may be at least substantially free of Group VIII metal or alloy catalyst material. The cutting element may further include a substrate and an adhesion material between and bonded to the cutting table and the substrate. The adhesion material may include diamond particles bonded to one another and to the cutting table and the substrate after formation of the preformed cutting table. | 1 |
TECHNICAL FIELD
This invention relates to selectively eradicating plants, and more particularly to mechanically thinning and/or weeding crops in an automated manner.
BACKGROUND
Cultivating crops often involves routine thinning and weeding of the crops. Thinning a field of plants can include destroying and/or removing certain plants in order to maintain a desired spacing between remaining plants (e.g., saved plants). Weeding a field of plants can include destroying and/or removing undesired growths located in proximity to the plants. Thinning and weeding are often performed manually using a standard garden tool (e.g., a hoe) to remove a plant or weed, which can be a laborious task. Thinning and weeding may also be performed using chemical treatments (e.g., fertilizers or herbicides) that may be sprayed on the plants and weeds to chemically kill the plants and weeds. Such chemical treatments can require precise application, may be limited in chemical effectiveness, and may be prohibited on certain (e.g., organic) farms. Additionally, manual and chemical thinning and weeding techniques may be associated with significant costs, risks to personnel safety, and risks to food safety.
SUMMARY
The invention involves a realization that mechanically thinning and weeding plants in an automated manner can increase the precision of a thinning and weeding operation, while eliminating the need to use chemical treatments, eliminating disadvantages associated with such treatments, and reducing costs associated with manual thinning and weeding operations.
One aspect of the invention features a method of selectively eradicating plants, including generating images of multiple plants arranged in a bed using a camera mounted to a mobile chassis moving along the bed, determining respective locations of the multiple plants from the generated images, selecting from among the multiple plants one or more target plants to be eradicated, and eradicating the one or more target plants by accelerating a blade of a rotary cutter to strike the one or more target plants as the mobile chassis moves along the bed, and to decelerate the blade to avoid eradicating unselected plants as the mobile chassis moves along the bed, wherein the rotary cutter is carried by the mobile chassis and rotatable about an axis extending in the direction along which the mobile chassis is moved.
Another aspect of the invention features a plant eradication system that includes a mobile chassis, a camera carried by the mobile chassis and configured to generate images of the multiple plants arranged in a bed as the mobile chassis is moved in a direction along the bed, a processor configured to determine respective locations of the multiple plants from the generated images, a controller configured to select one or more target plants from among the multiple plants for eradication, and a rotary cutter carried by the mobile chassis and rotatable about an axis extending in the direction along which the mobile chassis is moved along the bed, wherein the rotary cutter is responsive to the controller to accelerate a blade of the rotary cutter to strike a selected plant as the mobile chassis is moved along the bed, and to decelerate the blade to avoid eradicating unselected plants as the mobile chassis is moved along the bed.
In some embodiments, the camera that is directed towards the bed and a processor is operable to analyze the images.
In certain embodiments, a hood surrounds the camera.
In some embodiments, the method further includes identifying the multiple plants in the image using a recognition algorithm.
In certain embodiments, the multiple plants include one or more of beets, carrots, lettuce, romaine, onions, parsnips, radishes, rutabagas, spinach, corn, and turnips.
In certain embodiments, selecting the one or more target plants includes comparing the respective locations of the multiple plants to a predetermined spacing.
In some embodiments, the method further includes identifying one or more plants that are positioned within the predetermined spacing as the one or more target plants.
In certain embodiments, eradicating the one or more target plants includes severing leaves and stems of the one or more target plants.
In some embodiments, the method further includes identifying one or more weeds in the bed using a recognition algorithm.
In certain embodiments, the method further includes cutting the one or more weeds using the rotary cutter.
In some embodiments, the rotary cutter includes one or more arms extending from a rotational center of the rotary cutter and defining gaps therebetween and one or more blades that extend from ends of the one or more arms, respectively.
In certain embodiments, the rotary cutter is responsive to a controller to position the rotary cutter such that the unselected plants pass through the one or more gaps.
In some embodiments, the one or more blades are configured to cut the multiple plants.
In certain embodiments, the one or more blades extend from the one or more arms in a direction of travel of the mobile chassis.
In some embodiments, the one or more blades extend from the one or more arms in a direction opposed to a direction of travel of the mobile chassis.
In certain embodiments, arms of the rotary cutter are oriented within a single plane.
In some embodiments, arms of the rotary cutter are oriented within respective perpendicular planes.
In certain embodiments, the method further includes eradicating the one or more target plants by dragging the rotary cutter along the bed.
In some embodiments, the rotary cutter is movable via a floating frame configured to move vertically as a function of a height of the surface of the bed.
In certain embodiments, a vertical adjustment device is mounted to the floating frame, the vertical adjustment device supporting the rotary cutter.
In some embodiments, prior to eradicating the one or more target plants, the rotary cutter is moved in a lateral direction by an actuator configured to translate the rotary cutter.
In certain embodiments, the images are generated, the respective locations of the multiple plants are determined, the one or more target plants are selected, and the one or more target plants are eradicated, while the mobile chassis moves at a constant speed along the bed.
In some embodiments, the controller is configured to control the rotary cutter via one or more of a rotary motor and an actuator.
In some embodiments, the plant eradication system further includes a floating frame that is configured to move vertically as a function of a height of a surface of the bed.
In certain embodiments, the plant eradication system further includes a vertical adjustment device that is mounted to the floating frame, the vertical adjustment device supporting the rotary cutter.
In some embodiments, the plant eradication system further includes a rotary motor that is communicably coupled to the controller and that is configured to rotate the cutter.
In certain embodiments, the plant eradication system further includes an actuator that is communicably coupled to the controller and that is configured to translate the cutter.
In some embodiments, the plant eradication system further includes an encoder that is communicably coupled to the controller and that is configured to detect a speed at which the chassis moves along the bed.
In certain embodiments, the plant eradication system operates autonomously.
In some embodiments, the plant eradication system is moved along the bed by a tractor.
Embodiments may include one or more of the following advantages. The method and system may be used to mechanically thin and weed undesired plants without damaging desired plants that are to be saved and without using chemical treatments (e.g., fertilizers or herbicides) to remove the undesired plants and weeds. Accordingly, expenses that would otherwise be incurred by purchasing and using chemical treatments and the risks to food safety associated with using such chemical treatments may also be substantially reduced or eliminated. In some examples, the mechanical action performed by the plant eradication system can be particularly beneficial on organic farms, where the use of certain chemical treatments may be prohibited. Furthermore, the automated actions performed by the plant eradication system can alleviate the need to manually identify and remove undesired plants and weeds, thereby saving time and substantially reducing costs.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the invention will be apparent from the description, drawings, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a rear perspective view of a thinning and weeding system.
FIG. 2 is a front perspective view of the thinning and weeding system of FIG. 1 .
FIG. 3 is a perspective view showing a portion of the thinning and weeding system of FIG. 1 , including a cutter with arms oriented within a single plane, as the cutter eradicates a plant disposed within a bed of plants.
FIG. 4 is a perspective view showing the portion of the thinning and weeding system of FIG. 3 , including the cutter, as the cutter passes over a plant disposed within the bed of plants.
FIG. 5 is a perspective view showing a portion of the thinning and weeding system of FIG. 1 , including a lower frame that supports the cutter of FIG. 3 .
FIG. 6 is a rear perspective view showing the portion of the thinning and weeding system of FIG. 5 , including the lower frame that supports the cutter of FIG. 3 .
FIG. 7 is a flow chart of an example process for thinning and/or weeding crops.
FIG. 8 is a perspective view showing a portion of a thinning and weeding system, including a cutter with arms oriented within perpendicular planes.
FIG. 9 is a perspective view showing a portion of a thinning and weeding system, including a cutter with wide-blade knives.
FIG. 10 is a perspective view showing a portion of a thinning and weeding system, including a cutter with a single arm and knife.
FIG. 11 is a rear perspective view of the thinning and weeding system of FIG. 1 , assembled with a tractor.
Like reference symbols in the various figures indicate like elements.
DETAILED DESCRIPTION
A thinning and weeding system for thinning and weeding a variety of crops will be described below. In some embodiments, the thinning and weeding system includes mechanical cutters, a machine vision system, and associated control elements that allow the thinning and weeding system to mechanically remove undesired crops and save desired crops in an automated manner, thereby substantially eliminating a need to use chemical treatments for thinning and weeding the crops. In some examples, the crops may be planted by seed. Example crops that may be thinned and weeded by the thinning and weeding system include beets, carrots, lettuce, romaine, onions, parsnips, radishes, rutabagas, spinach, corn, turnips, and other crops.
FIGS. 1 and 2 display rear and front perspective views, respectively, of a thinning and weeding system 100 that is operable to mechanically thin and weed a variety crops in an automated manner. In some examples, the thinning and weeding system 100 may be configured to operate autonomously, as will be described in more detail below, or may be configured to operate with other vehicles, as will be described in detail with respect to FIG. 11 . In the example of FIGS. 1 and 2 , the thinning and weeding system 100 is positioned over two spaced apart beds 101 of plants 103 that are located in a field of plants. As illustrated, the plants 103 are arranged in two opposing seed lines 105 along a surface 107 of each bed 101 . In some examples, the beds 101 may be spaced about 14 inches to about 22 inches (e.g., 18 inches) apart, depending on the type of plants 103 being cultivated in the beds 101 . In some examples, the two opposing seed lines 105 of plants 103 may be spaced about 10 inches to about 14 inches (e.g., 12 inches) apart along the bed 101 , depending on the type of plants 103 being cultivated in the beds 101 . In some examples, the plants 103 may be spaced about 1.5 inches to about 2 inches (e.g., 1.75 inches) apart, depending on the type of plants 103 being cultivated.
The thinning and weeding system 100 includes an upper frame 102 supported by four outer wheels 104 , two adjacent lower frames 106 that are each supported by two inner wheels 108 , and two electrical enclosures 110 mounted to opposing sides of the upper frame 102 . The thinning and weeding system 100 further includes a machine vision system 112 that identifies plants 103 and weeds (not shown) that need to be removed from the surfaces 107 of the beds 101 and a programmable logic controller (PLC) that is located within one of the electrical enclosures 110 and that is electrically coupled to the machine vision system 112 . The thinning and weeding system 100 additionally includes four cutters 114 that are operable to mechanically remove the identified plants 103 and weeds from the surfaces 107 of the beds 101 , four respective motors 116 that are operable to rotate the cutters 114 , and an encoder 128 that is operable to detect an angular velocity of the outer wheels 104 . Additionally, the thinning and weeding system 100 includes a GPS system (located, for example, within one of the electrical enclosures 110 ) that provides a field location to the PLC and a generator (not shown) that provides power to the thinning and weeding system 100 . The thinning and weeding system 100 further includes high capacity batteries 120 that can power the thinning and weeding system 100 for a limited period of time should the generator malfunction.
The various components of the thinning and weeding system 100 may be powered by, for example, hydraulic or electrical mechanisms that are known to a person skilled in the art. In some examples, the generator converts the hydraulic power to electrical power to provide functionality to the various components of the thinning and weeding system 100 .
In some embodiments, the outer wheels 104 have a radius of about 6 inches to about 12 inches (e.g., 9 inches), thereby positioning the upper frame 102 (e.g., and any components mounted to the upper frame 102 ) of the thinning and weeding system 100 above the level of the field. In some embodiments, the inner wheels 108 have a radius of about 2 inches to about 4 inches (e.g., 3 inches), thereby positioning the lower frames 106 (e.g., and any components mounted to the lower frame 106 ) of the thinning and weeding system 100 above the surfaces 107 of the beds 101 of plants 103 . In this manner, the lower frames 106 are floating frames that have an adjustable height relative to the upper frame 102 such that the thinning and weeding system 100 may adapt to a variable height of the surfaces 107 of the beds 101 of plants 103 . As illustrated, the lower frames 106 are attached to opposing sides of the upper frame 102 such that each lower frame 106 is aligned with a respective bed 101 of plants 103 . In some embodiments, the lower frame 106 is attached to the upper frame via a four bar linkage mechanism.
Still referring to FIGS. 1 and 2 , the machine vision system 112 includes two cameras 122 and two respective hoods 124 that surround the cameras 122 . The cameras 122 and the hoods 124 are located along a frontal member 126 of the upper frame 102 . The cameras 122 are oriented and positioned to image respective fields of view along the beds 101 of plants 103 . In the example embodiment of FIGS. 1 and 2 , the cameras 122 and the respective hoods 124 may be spaced apart by about 38 inches to about 44 inches (e.g., 40 inches) along the frontal member 126 of the upper frame 102 . The hoods 124 are adapted to block (e.g., reduce the amount of) natural light (e.g., which varies depending on a season, weather, and a time of day) from impinging upon the fields of view.
The cameras 122 include light-emitting diodes (LEDs) and filters for sufficient illumination and desired image characteristics. The cameras 122 may be standard resolution, color video graphics array (VGA) cameras known to a person skilled in the art. For example, the cameras 122 may have a pixel count of 480×640, thereby allowing each camera 122 to capture both seed lines 105 of the respective bed 101 of plants 103 within one field of view (e.g., a 14 inch×18 inch field of view). The camera resolution (e.g., pixel dimension) of such a field of view may be 0.030 inch, which is adequate for identifying individual leaves of the plants 103 and weeds. Processors of the cameras 122 may have a frame processing time of 25 ms and accordingly allow the cameras 122 to acquire images at a rate of 40 fps, which is fast enough to map locations of the plants 103 while the thinning and weeding system 100 moves at a predetermined speed (e.g., 2 ft/sec). Following capture of an image by a camera 122 , the image is processed by the processor of the camera 122 and further analyzed according to an algorithm that identifies a location (e.g., using an XY coordinate system) of a plant 103 or weed with respect to the camera 122 , as will be described in more detail with respect to FIG. 7 .
FIGS. 3 and 4 display perspective views of one of the cutters 114 while cutting an undesired plant 103 and while saving a desired plant 103 and, respectively. Two cutters 114 are mounted to each lower frame 106 and are spaced apart such that the cutters 114 are located on opposing sides of the inner wheels 108 of the respective lower frames 106 . The cutter 114 is operable to rotate with respect to the lower frame 106 about an axis this parallel to a direction of travel of the thinning and weeding system 100 . Each cutter 114 is rotated by the respective motors 116 (e.g., servo-controlled motors) located near centers of the cutters 114 , as will be described in more detail with respect to FIG. 7 .
The cutter 114 includes four arms 115 and four respective knives 132 (e.g., blades) that extend from ends of the arms 115 . The arms 115 of the cutter 114 have a generally rectangular shape and are oriented within a single plane that is substantially perpendicular to a direction of travel of the thinning and weeding system 100 . The arms 115 of the cutter 114 are further oriented perpendicular to each other. Accordingly, the knives 132 are spaced about 90 degrees apart from each other. The configuration of the cutter 114 defines four gaps 130 that allow desired plants 103 to be saved as the cutter 114 rotates with respect to the lower frame 106 while the thinning and weeding system 100 moves along the beds 101 of plants 103 . Accordingly, the gaps 130 include an angle of about 90 degrees. The arms 115 of the cutter 114 are generally sized such that the gaps 130 of the cutter 114 may be aligned to surround the desired plants 103 as the cutter 116 rotates. In some examples, the arms 115 have a width of about ¾ inch to about 1.5 inches (e.g., 1 inch), a length of about 4 inches to about 6 inches (e.g., 5 inches), and a thickness of about ⅛ inch to about ⅜ inch (e.g., ¼ inch). In some examples, the cutter 114 may be rotated at a speed of about 150 rpm to about 250 rpm (e.g., 200 rpm).
The knives 132 are configured to sever leaves and stems from roots of undesired plants 103 as the cutter 114 rotates with respect to the lower frame 106 while the thinning and weeding system 100 moves along the beds 101 of plants 103 . The knives 132 extend substantially perpendicularly from respective ends of the arms 115 towards the direction of travel of the thinning and weeding system 100 . The knives 132 have a generally triangular shape. In some examples, the knives 132 have a width of about ¾ inches to about 1.5 inches (e.g., 1 inch), a length of about 1.5 inches to about 3 inches (e.g., 2 inches), and a thickness of about 1/16 inch to about 3/16 inch (e.g., ⅛ inch).
FIGS. 5 and 6 displays perspective views of two cutters 114 supported by the lower frame 106 of the thinning and weeding system 100 . In particular, each cutter 114 is supported by a vertical adjustment device 134 that is mounted to the lower frame 106 and that includes an internal rotating gear mechanism (e.g., a threaded rod). The vertical adjustment device 134 can variably lower the cutter 114 to an appropriate location above the surface 107 of the bed 101 . Additionally, two actuators 136 (e.g., servo drive actuators) are located on each lower frame 106 and are operable to translate the respective cutters 114 in a direction transverse to the seed lines 105 such that the cutters 114 can be aligned with the seed lines 105 as the seed lines 105 vary in position (e.g., lateral position). Accordingly, the cutters 114 may also be positioned to remove weeds located between the opposing seed lines 105 . Cam rollers 138 mounted to respective vertical adjustment devices 134 allow the cutters 114 to move smoothly with respect to the lower frames 106 as the thinning and weeding system 100 moves along the beds 101 of plants 103 .
In operation, the thinning and weeding system 100 travels along the beds 101 of plants 103 . In some examples, the thinning and weeding system 100 travels in an autonomous manner. For example, the thinning and weeding system 100 uses analyses of the images captured by the machine vision system 112 , as well as field locations provided by the GPS system, to guide itself along the beds 101 of plants 103 . Additionally, the thinning and weeding system 100 uses a field mapping provided by the GPS system to determine when the thinning and weeding system 100 has reached an edge of the field and accordingly when to turn and travel in a different direction.
As the thinning and weeding system 100 travels in the field, wireless communication is maintained over a network between a remote operator and the PLC controller and GPS system so that a status of the thinning and weeding system 100 can be monitored. Example parameters that may be monitored by the remote operator include a field location of the thinning and weeding system 100 , a velocity of the thinning and weeding system 100 (e.g., an angular velocity of the outer wheels 104 and the inner wheels 108 ), a number and location of plants 103 that have been eradicated, a number and location of plants 103 that have been saved, a frame rate of the camera, and a rotational speed of the cutter 114 . The remote operator may change any of such parameters by sending a signal that includes a corresponding instruction over the network to the PLC of the thinning and weeding system 100 . The PLC may accordingly control the corresponding components of the thinning and weeding system 100 . In some examples, the remote operator may monitor and control multiple thinning and weeding systems 100 simultaneously.
In some examples, the thinning and weeding system 100 travels at a speed of about 1 ft/sec to about 3 ft/sec (e.g., about 2 ft/sec). The thinning and weeding system 100 moves with respect to the beds 101 of plants 103 such that each camera 122 images a respective bed 101 of plants 103 . Accordingly, the outer wheels 104 rotate along outer edges of the beds 101 , and the inner wheels 108 rotate between opposing seed lines 105 of respective beds 101 .
FIG. 7 displays a flow chart of an example process 200 that may be implemented to thin and/or weed the beds 101 of plants 103 using, for example, the thinning and weeding system 100 . As the thinning and weeding system 100 travels, the cameras 122 generate images of the beds 101 of plants 103 ( 202 ). In some examples, the cameras 122 acquire images at a rate of 20 fps to 60 fps (e.g., 40 fps). In some examples, the filters on the cameras 122 may produce an image that highlights the plants 103 and weeds in respective desired colors and shows the soil in grayscale. Once the images are acquired, the images are analyzed using algorithms implemented by the respective camera processors. The images may be analyzed using standard algorithms known to a person skilled in the art. In some examples, the analysis identifies the individual plants 103 and weeds and determines their respective locations (e.g., in an XY coordinate system) ( 204 ) with respect to the camera 122 . In some examples, the processor may distinguish a plant 103 from a weed using a standard recognition algorithm (e.g., pattern recognition) known to a person skilled in the art. The locations of the identified plants 103 and weeds are sent to the PLC, and the PLC determines which plants 103 (e.g., selects target plants) and weeds should be removed from the surface 107 of the beds 101 ( 206 ) and which plants 103 should be saved. In some examples, the PLC determines which plants 103 should be removed and which plants 103 should be saved by comparing the locations of the identified plants 103 to a predetermined spacing between consecutive plants 103 . For example, plants 103 located at certain interval locations (e.g., corresponding to the predetermined spacing) may be saved, while plants 103 located within the interval locations may be eradicated. In some examples, the predetermined spacing may be between about 8 inches and about 12 inches (e.g., 10.5 inches), depending on the type of plants 103 being cultivated.
As the thinning and weeding system 100 travels along the beds 101 of plants 103 , the encoder 128 monitors an angular speed of the outer wheels 104 and sends this information to the PLC. Using the speed of the outer wheels 104 and the determination of which plants 103 should be destroyed and saved, the PLC determines a relationship (e.g., calculates a distance) between the cutters 114 and the plants 103 and weeds. The PLC accordingly controls the motors 116 and the actuators 136 such that the cutters 114 eradicate the undesired plants 103 and weeds by cutting the undesired plants and weeds ( 208 ) and pass over the desired plants 103 . For example, the cutters 114 may be rotationally accelerated such that the cutters 114 sever leaves from the undesired plants 103 and weeds (e.g., thereby preventing the plants 103 and weeds from growing further). In some examples, the cutters 114 may be rotationally decelerated such that the cutters 114 avoid desired plants 103 (e.g., such that the gaps 130 of the cutters 114 surround the desired plants 103 ). In this manner, the cutters 114 are rotated at a variable angular speed according to which plants 103 will be destroyed and which plants 103 will be saved. In some examples, two opposing cutters 114 may be rotated synchronously along opposing seed lines 105 . In some examples, the two opposing cutters 114 may be rotated asynchronously along the opposing seed lines 105 .
Accordingly, the thinning and weeding system 100 may be used to mechanically eradicate undesired plants 103 and weeds within the beds 101 of plants 103 without damaging the desired plants 103 that are to be saved and without using chemical treatments (e.g., fertilizers or herbicides) to eradicate the undesired plants 103 and weeds. Accordingly, expenses that would otherwise be incurred by purchasing and using chemical treatments and the risks to food safety associated with using such chemical treatments may also be substantially reduced or eliminated. In some examples, the mechanical action performed by the thinning and weeding system 100 can be particularly beneficial on organic farms, where the use of certain chemical treatments may be prohibited. Furthermore, such automated actions performed by the thinning and weeding system 100 can alleviate the need to manually identify and remove undesired plants 103 and weeds, thereby saving time and substantially reducing costs.
While the thinning and weeding system 100 has been described and illustrated as including two lower frames 106 with respective cameras 122 , cutters 114 , and other associated components, in some embodiments, a thinning and weeding system may include more than two lower frames with respective cameras, cutters, and other associated components in order to thin and weed multiple respective beds of plants. In such cases, an upper frame of the thinning and weeding system may be sized for appropriate accommodation of the number of lower frames.
While the thinning and weeding system 100 has been described and illustrated as including two cutters 114 located on opposing sides of the inner wheels 108 of the lower frames 106 , in some embodiments, a thinning and weeding system may include a different number of cutters 114 (e.g., three cutters 114 ) in order to thin and weed a bed of plants 103 including more than two seed lines 105 or in order to remove weeds located between the seed lines 105 .
While the thinning and weeding system 100 has been described as including the cutter 114 with arms 115 that are oriented in a single plane that is substantially perpendicular to the direction of travel of the thinning and weeding system 100 , in some embodiments, a thinning and weeding system may include a cutter with arms that are oriented in respective perpendicular planes. For example, FIG. 8 displays a perspective view of a portion of a thinning and weeding system 300 that includes a cutter 314 that includes arms 315 that are oriented in respective perpendicular planes. The thinning and weeding system 300 is substantially similar in construction and function to the thinning and weeding system 100 , with the exception that the thinning and weeding system 300 includes the cutter 314 instead of the cutter 114 . For example, the thinning and weeding system 300 includes the machine vision system 112 , the lower frames 106 , the inner wheels 108 , the vertical adjustment devices 134 , the motors 116 , the actuators 136 , and other components of the thinning and weeding system 100 .
The cutter 314 is substantially similar in construction to the cutter 114 , with the exception that arms 315 of the cutter 314 are oriented in respective planes that are perpendicular to each other. Accordingly, the cutter 314 defines four gaps 330 that are spaced about 90 degrees from each other and includes the knives 132 . In some examples, the cutter 314 may not be rotated but instead may be translated (e.g., pulled) along with the movement of the lower frame 106 in order to cut a series of undesired plants 103 and is operable to rotate with respect to the lower frame 106 in order to cut certain plants 103 . In some examples, once the cutter 314 approaches a plant 103 to be saved, the cutter 314 may be rotated such that the cutter 314 passes over the plant 103 . In some examples, the cutter 314 may be rotated at a speed of about 20 rpm to about 40 rpm (e.g., 30 rpm).
While the thinning and weeding systems 100 , 300 have been described as including the cutters 114 , 314 with knives 132 that extend from the arms 115 , 315 of the cutters 114 , 314 in a direction of travel of the thinning and weeding systems 100 , 300 , in some embodiments, a thinning and weeding system may include a cutter including knives that extend from the arms of the cutters in directions both along and opposed to a direction travel of the thinning and weeding system. For example, FIG. 9 displays a perspective view of a portion of a thinning and weeding system 400 that includes a cutter 414 that includes wide-blade knives 432 . The thinning and weeding system 400 is substantially similar in construction and function to the thinning and weeding systems 100 , 300 , with the exception that the thinning and weeding system 400 includes the cutter 414 instead of the cutter 114 or the cutter 314 . For example, the thinning and weeding system 400 includes the machine vision system 112 , the lower frame 106 , the inner wheels 108 , the vertical adjustment devices 134 , the motors 116 , the actuators 136 , and other components of the thinning and weeding system 100 .
The cutter 414 is substantially similar in function to the cutter 114 , with the exception that the cutter 414 includes the knives 432 that extend from the arms 115 of the cutters 414 in directions both along and opposed to a direction travel of the thinning and weeding system 400 . In some examples, the cutter 414 may advantageously cover more ground and accordingly cut more plant material (e.g., as compared to the cutter 114 ) for a given rotational speed. As a result, the cutter 414 may be rotated at a reduced angular speed (e.g., as compared to the angular speed of the cutter 114 ) while still covering the same amount of ground. Additionally, support of the knives 432 by the arms 115 along centers of the knives 432 reduces the torque load placed on the arms 115 by the knives 432 .
While the thinning and weeding systems 100 , 300 , 400 have been described as including the cutters 114 , 314 , 414 that include four arms 115 , 315 , 415 and four respective knives 132 , 432 extending in a plane of the cutters 114 , 314 , 414 , in some embodiments, a thinning and weeding system may include a cutter that has a different number of arms and knives. For example, FIG. 10 displays a perspective view of a portion of a thinning and weeding system 500 that includes a cutter 514 that includes one arm 315 and one knife 132 extending from an end of the arm 315 . The thinning and weeding system 500 is substantially similar in construction and function to the thinning and weeding systems 100 , 300 , 400 , with the exception that the thinning and weeding system 500 includes the cutter 514 instead of the cutter 114 , 314 , or 414 . For example, the thinning and weeding system 500 includes the machine vision system 112 , the lower frame 106 , the inner wheels 108 , the vertical adjustment devices 134 , the motors 116 , the actuators 136 , and other components of the thinning and weeding system 100 .
The cutter 514 is substantially similar in function to the cutter 314 , with the exception that the cutter 514 includes one arm 315 and one knife 132 instead of four arms 315 and four knives 132 . Accordingly, in some examples, the cutter 514 may not be rotated but instead may be translated (e.g., pulled) along with the movement of the lower frame 106 in order to destroy a series of undesired plants 103 and is operable to rotate with respect to the lower frame 106 in order to cut the undesired plants 103 . In some examples, once the cutter 514 approaches a plant 103 to be saved, the cutter 514 may be rotated such that the cutter 514 passes over the plant 103 . In some examples, the cutter 514 may be rotated at a speed of about 100 rpm to about 140 rpm (e.g., 120 rpm). The single-arm configuration of the cutter 514 provides the cutter 514 with a lower inertia than the cutter 314 and accordingly requires less power to achieve a given rotational speed.
While the thinning and weeding system 100 has been described as operating autonomously, in some embodiments, any of the thinning and weeding systems 100 , 300 , 400 , 500 may be attached to a vehicle (e.g., tractor) that is operable to pull the thinning and weeding system 100 , 300 , 400 , 500 . For example, FIG. 11 displays the thinning and weeding system 100 attached to a tractor 109 . The thinning and weeding systems 100 , 300 , 400 , 500 may be attached to the tractor 109 via a three-point hitch or any other suitable attachment mechanisms known to a person skilled in the art. In the example of FIG. 11 , the tractor 109 is controlled by an operator (e.g., who rides the tractor 109 ) using a wireless monitor (not shown) to control the thinning and weeding system 100 as the thinning and weeding system 100 travels along the beds 101 of plants 103 . Accordingly, the operator of the tractor 109 may determine one or more of the various operational parameters (e.g., a travel speed) of the thinning and weeding system 100 .
Thus, while a number of examples have been described for illustration purposes, the foregoing description is not intended to limit the scope of the invention, which is defined by the scope of the appended claims. There are and will be other examples and modifications within the scope of the following claims. | A method of selectively eradicating plants includes generating images of multiple plants arranged in a bed using a camera mounted to a mobile chassis moving along the bed, determining respective locations of the multiple plants from the generated images, selecting from among the multiple plants one or more target plants to be eradicated, and eradicating the one or more target plants by accelerating a blade of a rotary cutter to strike the one or more target plants as the mobile chassis moves along the bed, and to decelerate the blade to avoid eradicating unselected plants as the mobile chassis moves along the bed, wherein the rotary cutter is carried by the mobile chassis and rotatable about an axis extending in the direction along which the mobile chassis is moved. | 0 |
BACKGROUND OF THE INVENTION
This invention relates to a spinning machine, in particular to a machine for home spinning of wool and other fibres. The discussion and description of the invention will refer to wool, but the changes that are needed to apply the invention to other fibres, natural and synthetic, are obvious to those skilled in the art.
The invention relates to a machine which combines the key operations of carding raw greasy wool as well as scoured wool, wool tops and slivers, and subsequently spinning the resultant band of carded or combed wool into yarn. In particular this invention relates to a device suitable for use in the home or in cottage type industry in developing countries for the purpose of conveniently and quickly processing wool fibres into yarn of the type known as home or hand-spun yarn which is currently being sold at a premium in world markets through being said to have been spun in natural wool grease.
To prepare raw wool for use in weaving, there are two principal steps. Firstly the individual strands are separated and laid approximately parallel to each other in a band. This can variously be called carding, combing or drawing out, and the result is sliver. Secondly, the band is twisted (spun) into a yarn, which, unlike the band from which it is formed, has a considerable tensile strength.
Wool fibres growing on the back of sheep are intimately associated with an animal fat known variously as lanolin, lanum, hydrous wool fat and by other names. This substance, consisting chiefly of cholesterol and isocholesterol esters of the higher fatty acids, imparts important water shedding as well as thermal insulating and dirt resistant properties to raw fleece wool. The unctuous and sticky nature of wool fat results in clogging and inefficiency in machines currently used for commercially carding wool so that normal practice requires raw wool to be scoured and washed prior to carding, and to be subsequently re-oiled as sliver in order to be spun. Normal commercial practice in large scale spinning therefore requires two additional operations, scouring and re-oiling, not necessary if wool fibres could be carded in the natural wool fat. In addition the removal of the wool fat results in the loss of some water shedding, thermal insulating and dirt repelling properties in the finished yarn. For carding in conjunction with traditional wheel spinning, considerable skill is needed, if a steady and regulated amount of sliver is continuously to be fed to the spinning head. In the absence of sufficient skill, the yarn produced is uneven.
It is an object of the present invention to provide a spinning machine which will go some way to overcoming the aforementioned difficulties in handling unscoured or unwashed wool both for home and commercial use, as well as effecting improvements in overcoming the aforementioned difficulties in small scale spinning, or will at least provide the public with a useful choice.
BRIEF SUMMARY OF THE INVENTION
Briefly the invention contemplates a spinning machine including a tube which contains a reel on which yarn when spun is to be reeled. The yarn is fed to the reel through a hole in the wall of the tube. It is fed to the hole from a tubular guide fixed on the axis of the tube and co-operating with a corresponding fixed tubular guide into which sliver is fed. The tube is rotated, and relative motion between the two guides supplies the twist needed for spinning. The reel is rotated, at a speed different from that of the tube, by rolling on the inner surface of the tube. The difference of speeds supplies the relative rotation between tube and reel that is needed for reeling the yarn. This difference of speed may be controlled by the tightness with which the operator holds the yarn as it is spun, or by a brake. The machine is small, so that it can be used in a small room or a crowded flat, and it produces even yarn more easily than does a spinning wheel, and it does it more quickly. It will handle fleece wool in the greasy state.
A carder of fleece wool may be incorporated. It consists of an array of plates, serrated on an edge, and assembled in a block whose midline is continuous with the entry to the fixed guide.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more readily understood and carried into effect, reference is made to the accompanying drawings which, together with their description, are offered by way of example only and are not to be taken as limiting the invention, the scope of which is defined by the appended claims rather than any preceding description.
In the drawings:
FIG. 1 is an elevation from a side view of one embodiment of the invention.
FIG. 2 is a simplified perspective view of a second embodiment of the invention.
FIG. 3 is similar to FIG. 2 but with parts broken away to show the driving arrangement.
FIG. 4 is a broken away view, from the back as seen in FIG. 2, to show one arrangement for moving the reel axially and for braking it.
FIG. 5 is a broken away view from the front to show other aspects of the means for moving the reel axially.
FIG. 6 is an enlarged view of a part of FIG. 1 to show one variant of a second arrangement for moving the reel axially.
FIG. 7 is a detail of another variant of FIG. 6.
FIG. 8 is an enlarged view of a part of FIG. 4 to show the braking arrangements in more detail.
FIG. 9 is an enlarged cross sectional view of the fixed and rotating guides on the line B B in FIG. 1.
FIG. 10 is a cross section at A A in FIG. 1 of the carder.
FIG. 11a and 11b are side views of alternate leaves of the carder of FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
The first part of the description relates to spinning only; carding is introduced later.
In spinning, a loose band of more or less parallel fibres called a sliver is twisted into a yarn which is of very considerable length, and is conveniently stored on a cop or reel. A machine for spinning must provide three relative motions; a fast twist between sliver and yarn; a slower rotation of the reel on its axis to take up the yarn as it is formed, and a traverse of the yarn to and fro along the length of the reel to lay the yarn in layers as it is wound.
In the present machine the reel is contained within a tube of circular cross section which rotates about its axis near a feed arrangement for the sliver which does not rotate. This provides the spinning twist. The reel is carried round by the contact of its rim with the inner surface of the tube, with which the reel is approximately coaxial. Because the reel is smaller in diameter than the bore of the cylinder on which it rolls its speed of rotation, if free, is greater than the speed of rotation of the cylinder. It has been found satisfactory to make the reel diameter four fifths of the bore of the cylinder. Alternatively the speed of the reel may be controlled by a light brake. This provides a rotation relative to the tube and is the motion which winds the yarn on the reel. The reel is oscillated along its axis within the tube. This is the layering motion.
Although size is by no means an essential of this invention, it will be assumed for convenience of description that a reel 1 that is 12cm between cheeks and 7.2cm in diameter is to be filled. The reel lies approximately axially within a circular tube 3 of bore 9cm and length 25cm. The tube can conveniently be made of a clear plastic. One end is open, and the other end has fixed to it axially (conveniently by fixing in a closed end 5) a tube 7 of bore about 5mm. The tube projects about 2cm beyond the end of the tube of the large bore and has a transverse hole 9, communicating with the bore of the small tube, about 5mm out from the end of the large tube. Small tube 7, from its outer end and including transverse hole 9, forms a passageway for yarn 11, and is well smoothed and rounded. The outer end of small tube 7 projects towards the means 14 which feed sliver, and the spinning process takes place within the tube, and in the space between it and fixed tube 13.
Yarn is led from transverse hole 9 to the outer surface of large tube 3 where a groove 15 parallel to the axis leads the yarn to the mid-length of tube 3, to a hole 17 which penetrates to the interior of tube 3, and onto reel 1.
Large tube 3 with its contents is to be rotated to provide the spinning motion. The tube rests on two or more rollers 19 parallel to the axis of the tube. The rollers are rotated in phase by, for example, belt drive from an electric motor such as a sewing machine motor, controlled at variable speed by a foot control. Rollers 19 form a well known method of driving a tube, and it is known art to construct them so that they have enough friction with the tube without scratching the surface of the plastic. Clearly yarn 11 in passing along the length of tube 3 must not catch on drive rollers 19. It has been found that, if groove 15 is about 3mm wide and 3mm deep, the yarn runs free.
Yarn 11 is fed into the large tube 3 and towards the reel which is coaxially within tube 3, resting by its rims on the inner surface of tube 3. Clearly reel 1 will tend to be rotated as tube 3 is rotated. By means to be described later the reel is caused to rotate at a speed different from that of tube 3, and therefore different from that of yarn 11 which is held by tube 3. Yarn 11 will be wound on reel 1.
Projecting into the open end of tube 3 (i.e. at the end opposite from the feed of sliver) and connected to reel 1 is a linkage. It could be arranged as a cord and spring, but it has been found convenient to make it a rod 28 approximately coaxial with reel 1. Rod 28 is oscillated along its length by the length of the winding space on reel 1 at such a speed relative to the rotation of the reel that yarn 11 is wound in compact layers. Many methods of producing this oscillation are possible. In one, a cam is driven through suitable gearing or belts from electric motor 8, and a cam follower, held to the cam by a spring, is connected through a linkage to the rod to be oscillated.
In an alternative method shown in FIGS. 1, 6 and 7 motor 8 drives a feed rod 12 which has left and right hand threads. In FIG. 1 a general arrangement is shown, with block 10 representing schematically the two variants of FIGS. 6 and 7. In FIG. 6 two tumbling half-nuts 16 and 18 are mounted on sector plate 22 which pivots on block 10, which slides on guide rod 20, and drives a shortened version of the rod 32 shown in FIG. 5. The rotation of the feed rod causes the half-nut which is engaged with it to move towards one end of the feed rod, where the tumbling half-nut 16 hits a stop 24 which disengages the first half-nut and engages a second half-nut so that the direction of feed of the reel is reversed. It is possible to ensure positive engagement and disengagement of the half-nuts by a permanent magnet spring arrangement. A half-nut is held into engagement with the threaded rod by a small permanent magnet, which may be the half-nut itself and the disengaging stops 24 are sprung so that movement towards a stop puts a disengaging force on the tumbling half-nut which is engaged. When the spring tension becomes greater than the retaining force of the magnet the tumbling action is carried through by the positive action on the stored energy of the system. The magnet of the half-nut that is now to be engaged assists with this movement and subsequently holds the second half-nut in position while traversing the length of the feed rod in the opposite direction.
The tumbling half-nuts can be dispensed with if the feed rod 12 has the endless, two-directional thread shown in FIG. 7.
A simpler form of control of the axial movement of the reel 1 is shown in FIGS. 2, 4 and 5. The inner end of rod 28 carries a fork 35 which runs in a groove 34 in an axial projection 36 from reel 1. Any longitudinal movement of rod 28 will cause reel 1 to move axially. The remote end of rod 28 is rigidly attached, for instance by cross bar 30, to rod 32 which is parallel to rod 28 and is brought out, in a position convenient to the operator's hand, to the front of the base 2 of the spinning machine, where it is fitted with a knob 33. Rod 32 has a number of notches 35 where it passes through base 2. A spring-loaded detent (not shown) is fixed to the base and engages lightly one of notches 35. As the operator spins, knob 33 is pushed or pulled to move reel 1 at an intermittent speed that will cause yarn 11 to wind uniformly on reel 1.
Reel 1, being smaller than cylinder 3 in which it rolls, will when free rotate faster than the cylinder and therefore will wind yarn 11 on reel 1. But the reel is not free. The operator causes the sliver to be spun by holding it back against the tendency of the spinning machine to take it through fixed guide 13. This causes tension in yarn 11 right up to its contact with reel 1, and therefore slows down reel 1 and controls the rate of winding. This method needs some degree of skill because too much tension in yarn 11 will cause reel 1 to slow down to the speed of cylinder 3 so that no yarn is wound.
An alternative method of controlling the speed of reel 1 is shown in FIGS. 4 and 8. Rod 28, as already stated, engages at its inner end with an axial grooved projection from reel 1. From fork 35 is slung a loop 37 of cord as shown in FIG. 8. Engaging with a further groove 38 of projection 36 is a cord 39, anchored to rod 28, and passing through an eye 41 on it. Wheel 43 is a diagrammatic representation of a means, which could be a screwed rod working in a saddle, of tightening cord 39. Loop 37 pressing upwards and cord 39 pressing downward co-operate to form a brake on reel 1. They are also arranged to hold reel 1 against the inner surface of tube 3.
When reel 1 is fitted with a brake, it will normally rotate slower than cylinder 3. The tension of yarn 11 can still be used as a fine adjustment of the speed of the reel, but the effect is now different. The unbraked reel normally rotates faster than the cylinder, and the braked reel normally slower. Increasing the yarn tension on an unbraked reel will cause the rate of reeling of yarn to decrease. Increasing the tension with a braked reel will cause the rate of reeling of yarn to increase.
Rollers 19 may be supported in many ways. FIG. 1 shows one possible method, based on a frame constructed by known means. FIGS. 2 and 3 show another possible method, based on a moulding. Clearly rollers 19 must be carried in bearings 21. In the pattern of FIG. 1 these can be supported from a base plate 23. Motor 8 and its associated gearing or belts 6 and any oscillation drive that is used can be accommodated on the base plate and be covered. The working parts are still more completely covered in the design shown in FIG. 2.
The general design as shown in FIGS. 1 and 2, especially that in FIG. 2, are arranged to pack away neatly. The carder 25 is held by a tongue and groove arrangement; cylinder 3 lifts off; rod 32 can be telescopic and in two parts held together in use by a spring clip so that, when brake cord 39 is released, rods 28 and 32 can be lifted off. The various loose parts can be stored in sub-base 4, clipped to base 2 or, for FIG. 1, on base 23.
One effect of the tension in yarn 11 has already been referred to. A second effect is that the whole of the rotating system is pulled towards the fixed support for the sliver. To deal with this, the sliver support ends in fixed guide 13 which is a tube corresponding to and in line with tube 7 (the first guide) by which yarn 11 enters the rotating system. The first guide 7 is on the axis of rotation of tube 3, so that yarn 11 in entering it moves only in rotation, and not in translation. The first or rotating guide 7 can therefore press against the second or fixed guide 13 without interfering with the movement of the yarn during the spinning process, and second guide 13 can function as a stop for the rotating part of the spinning machine. Since the sliver must pass through the tube which is the second guide, this must be smooth and well rounded. It would normally be a straight tube, but it may include a bend.
If the operator wishes, the sliver can be presented to second guide 13 by hand, but it is considered that a new form of feed arrangement 25, shown in FIGS. 1 and 2, and in detail in FIGS. 10 and 11a and 11b, leads to a better yarn. Leading to the entrance to second guide 13 is a carding comb 27 which is formed of segments, some of which are sawtooth and are arranged so that movement towards guide 13 is not much impeded but movement away from it is impeded. Comb 27 may be flat, or it may form, as in FIG. 10, a channel leading towards guide 13, and the channel may decrease in cross section towards guide 13.
It is possible for it to begin as flat and to develop into a channel towards the guide.
Two forms of carding comb have been found satisfactory, one static and the other driven. Both are based on a construction using a stack of sheets, in which the sawteeth are formed on an edge on some or all of the sheets. The static form is cheaper to make, and is more easily adapted to a channel shape. In it teeth 29 as in a saw are cut on one edge of a number of sheets of a material which may be a plastic about 0.5mm thick, 10cm long, and any convenient width for clamping the sheets together. The sheets are assembled with the teeth aligned, and interposed are sheets 31 with smooth edges so assembled that the smooth edges are on the level of the bottom of the sawteeth. It may be an advantage if the smooth sheets are thinner than those with tooth edges, or if the toothed and smooth sheets are in a ratio greater than one. The total width of the stack of sheets should be approximately 2cm. It is found that when a lock of fibrous material is pulled over this device the fibres when aligned fall into the channels formed between the teeth by the intervening smooth edges.
In the second form of carding comb (not shown) there are once more two sets of sheets, of approximately the same dimensions as in the static form, but both sets are now tooth-edged. The two sets are again intermeshed, but each set is caused by cams or other means to lift, move forward, subside, and so move back and fro cyclically. The two sets move in antiphase. There is thus a continuous movement forward of the teeth that are in contact with the sliver. The teeth may be driven from the electric motor that drives the rollers.
The delivery end of either tooth device is presented to the entry to the fixed or second guide 13, whether this is in line with the axis of the reel 1, or is at an angle. The general axial line of the teeth, that is to say the working edge of the middle sheet, may be in line with the axis of the entry of the second guide 13, or it may feed upwards at an angle that may be as much as 45°.
Compared with the spinning machines used in mills, the present machine is very much cheaper and very much more compact.
Compared with a spinning wheel, it is more compact, an advantage in flats and small houses, it is completely safe, since dangerous moving parts can be covered, it has a reel with a large capacity, it spins continuously, it is easy to feed raw wool through the carder, and less judgement is needed since the wool on the carder is static. | This spinning machine weighs about 10 lbs. and is of about the size of a one foot cube. The reel on which the spun yarn is to be stored is contained within a large horizontal tube. The yarn is fed through a hole in the wall of the tube from a groove on the outer surface. The reel is rotated by running on the inner surface of the tube which is driven by, for instance, a sewing machine motor. By control of dimensions or by braking a relative speed is imposed between the reel and the tube and is the speed for reeling yarn. The yarn is fed to the groove from two small tubes, one stationary and the other rotating with the large tube. Both are coaxial with the large tube. Locks or sliver to be spun are presented to a surface with saw-tooth corrugations alternating with slots, and is fed to the stationary small tube. | 3 |
CROSS-REFERENCE AND RELATED APPLICATIONS
The subject application is a continuation-in-part of PCT international application PCT/CN2012/000873 filed on Jun. 25, 2012, which in turn claims priority on Chinese patent application No. CN 201210079324.X filed on Mar. 22, 2012. The contents and subject matter of the PCT and Chinese priority applications are incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to a femtosecond laser and method and apparatus for femtosecond laser pulse measurement based on transient-grating effect on a transparent medium, particularly, a self-referencing spectral interferometry method and apparatus for retrieving the spectral phase and pulse width that can be used to measure pulse in the 200-3000 nm spectral range. The present invention also relates to the application of the device for measuring megahertz repetition rate femtosecond laser pulses and single-shot femtosecond laser pulses.
BACKGROUND OF THE INVENTION
Femtosecond laser pulses had been applied broadly in various fields such as biological, medical, processing, communication, defense, and others. Femtosecond lasers and relative technologies have also been developed quickly. Recently, hot research fields, such as femtosecond chemistry, femtosecond nonlinear optical microscopy imaging of chemical and biological materials, are all based on femtosecond lasers. Attosecond laser pulse generation, X-ray laser, laboratory astrophysics, laser acceleration of electrons and protons, and other strong-field laser physics are all taking the advantage of femtosecond laser pulses as a research tool. In contrast to the nanosecond and picosecond lasers, femtosecond laser processing can get much more refined and smooth surface shape. Then it was widely used in the field of femtosecond laser micromachining. Femtosecond laser pulses has also recently been used for ophthalmic lens cutting operation, which greatly improves the quality and safety of the kind of surgery.
In the application of the laser, the pulse shape and the pulse width of the femtosecond laser pulse are important optical parameters. Real-time measurement or monitoring of these parameters are necessary in many experiments. Therefore, a simple, convenient, and effective method and apparatus for laser pulse measurement and real-time monitoring is important and promotes the development and application of femtosecond laser technology.
The technique for femtosecond laser pulse width measurement is evolving as the development of femtosecond laser technology. Currently, the most commonly used methods include autocorrelation method, See R. Trebino, Frequency - Resolved Optical Grating: The Measurement of Ultrashort Laser Pulses, Kluwer Academic Publishers (2000), frequency-resolved optical gating (FROG) method, See R. Trebino et al., “ Measuring ultrashort laser pulses in the time frequency domain using frequency - resolved optical gating,” Rev. Sci. Instrum. 68 (9), 3277-3295 (1997), and spectral phase interferometry for direct electric-field reconstruction (SPIDER) method, See C. Iaconis et al., “ Spectral phase interferometry for direct electric - field reconstruction of ultrashort optical pulses,” Opt. Lett. 23 (10), 792-794 (1998). Autocorrelation method is simple in the principles and structure but can not obtain the phase information of femtosecond laser pulses. FROG and SPIDER are used to get the pulse phase. However, FROG method usually need a long time to rebuild the pulse. SPIDER method usually requires a nonlinear optical crystal to convert the generated measurement signal. Because of the phase matching conditions in nonlinear optical crystals, each apparatus can only be adapted to a particular spectral range, thus limiting the application of the method in a wide spectrum range.
Recently, cross-polarized wave (XPW) generation, see A. Jullien et al., “ Spectral broadening and pulse duration reduction during cross polarized wave generation: influence of the quadratic spectral phase,” Appl. Phys. B 87 (4), 595-601(2007), is used as a reference light for self-referenced spectral interferometry (SRSI) method, see T. Oksenhendler et al., “ Self - referenced spectral interferometry,” Appl. Phys. B 99 (1), 7-12 (2010), to measure the femtosecond laser pulse. In this method, one incident beam is used without being divided into two beams. In the calculation, only three simple iterative calculations are needed to quickly obtain the spectra and spectral phase of the measured laser pulse, which is by far the most simple and convenient method. However, it requires the polarizer in the method. Then, the method is only valid for a particular wavelength, which also limits the application of the method and apparatus within a specific spectral range. The dispersion of the polarizer element also restricts the shortest pulse duration to be measured on 10 fs level. Recently, the self-diffraction effect based SRSI method has been used with the polarizer and relative restriction. In the method, the beam to be measured is divided into three beams. The current setup of the method is somewhat complex. See J. Liu et al., “ Self - referenced spectral interferometry based on self - diffraction effect,” J. Opt. Soc. Am. B 29 (I): 29-34 (2012).
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus based on the transient-grating effect on a transparent medium by using SRSI technique. The present invention provides a method and apparatus based on the transient-grating effect on a transparent medium by using the SRSI technique. The method and apparatus of the present invention eliminate the drawbacks of the conventional methods. In the method of the present invention, the laser to be measured is divided into four beams by using a black plate with four equal-sized holes. The setup is simple, easy to adjust, the data acquisition and processing is fast, and it is a one-shot measurement that can be adapted to the real-time measurement. The method and apparatus of the present invention is useful for monitoring pulses with different pulse widths and different wavelength.
The present invention provides a method based on the transient-grating effect using the SRSI technique to measure the femtosecond pulse. The method comprises the following steps:
{circle around (1)} the transient-grating effect (the laser to be measured is divided into four beams here) on a transparent medium is used to generate the reference light for an SRSI measurement;
{circle around (2)} the spectral interference fringes D (ω, τ) between the generated transient-grating light and the light to be measured is measured by a high precision spectrometer;
{circle around (3)} Based on the spectral interference fringes D (ω, τ), the spectral phase is retrieved by the SRSI calculation technique. Then, we can get the pulse width and pulse shape.
The present invention provides a first apparatus for femtosecond laser pulse measurement based on the transient-grating effect as shown in FIG. 1 , which is characterized in that it comprises a plate with four equal-sized holes (as shown in FIG. 4( a ) ), a delay plate, a plane reflective mirror, a first concave reflective mirror, a third-order nonlinear optical medium, an iris, a second concave reflective mirror, and a spectrometer with high spectral accuracy. The relationship of the components are shown as follows: the plate with the four equal-sized holes have four holes in a square shape; the first, second, and third quadrants of the plane reflective mirror are coated with high reflective film, and the fourth quadrant is uncoated; the femtosecond laser to be measured is divided into four beams after passing through the plate with four equal-sized holes. The four beams are referred to as the first, the second, the third, and the fourth beams. The first, the second, and the third beams are directly reflected by the first, the second, and the third quadrants of the plane mirror. The fourth beam passes through the delay plate, and then, is reflected by the uncoated fourth quadrant of the plane mirror. All the four beams are reflected onto the first concave mirror. A third-order nonlinear optical medium is located at the focal point of the first concave mirror. The first, the second, and the third beam are overlapped in the third-order nonlinear optical medium and generate a transient-grating signal light. The transient-grating light is collinearly overlapped with the fourth beam in space. After passing through the iris, the two beams are focused into the spectrometer with high spectral resolution by using the second concave reflection mirror. Thus, the interference spectrum is obtained for the SRSI measurement.
The plane mirror is a mirror of which the first, second, and third quadrants of the plane reflective mirror are coated with high reflective film, and the fourth quadrant is uncoated as shown in FIG. 4( b ) .
The present invention also provides a second apparatus for femtosecond laser pulse measurement based on the transient-grating effect as shown in FIG. 2 , which is characterized in that it comprises a plate with four equal-sized holes (as shown in FIG. 4( a ) ), a delay plate, a lens, a plane reflective mirror, a third-order nonlinear optical medium, an iris, a concave reflective mirror, and a spectrometer with high spectral accuracy. The relationship of the components are shown as follows: the plate with four equal-sized holes have four holes in a square shape; the first, second, and third quadrants of the plane reflective mirror are coated with high reflective film, and the fourth quadrant is uncoated; the femtosecond laser to be measured is divided into four beams after passing through the plate with four equal-sized holes. The four beams are referred to as the first, the second, the third, and the fourth beams. The first, the second, and the third beams directly pass through the lens and then are reflected by the first, the second, and the third quadrants of the plane mirror. The fourth beam passes through the delay plate and the lens, and then is reflected by the uncoated fourth quadrant of the plane mirror. A third-order nonlinear optical medium is located at the focal plane of the lens. The first, the second, and the third beam are overlapped in the third-order nonlinear optical medium and generate a transient-grating signal light. The transient-grating light is collinearly overlapped with the fourth beam in space. After passing through the iris, the two beams are focused into the spectrometer with high spectral resolution by the concave reflection mirror. Thus, the interference spectrum is obtained for the SRSI measurement.
The present invention further provides a third apparatus for femtosecond laser pulse measurement based on the transient-grating effect as shown in FIG. 3 , which is characterized in that it comprises a plate with four equal-sized holes (as shown in FIG. 4( a ) ), a delay plate, a first concave reflective mirror, a third-order nonlinear optical medium, an iris, a second concave reflective mirror and a spectrometer with high spectral accuracy. The relationship of the component parts are shown as follows: the first, second, and third quadrants of the first concave reflective mirror are coated with high reflective film, and the fourth quadrant is uncoated; the femtosecond laser to be measured is divided into four beams after passing through the plate with four equal-sized holes. The four beams are referred to as the first, the second, the third, and the fourth beams. The first, the second, and the third beams are directly reflected by the first, the second, and the third quadrants of the first concave reflective mirror. The fourth beam passes through the delay plate and then is reflected by the uncoated fourth quadrant of the first concave reflective mirror. A third-order nonlinear optical medium is located at the focal point of the first concave mirror. The first, the second, and the third beams are overlapped in the third-order nonlinear optical medium and generate a transient-grating signal light. The transient-grating light is collinearly overlapped with the fourth beam in space. After passing through the iris, the two beams are focused into the spectrometer with high spectral resolution by the second concave reflection mirror. Thus, the interference spectrum is obtained for the SRSI measurement.
The holes on the plate with four equal-sized holes may be of any shape. For example, the plate with the four equal-sized holes have the four holes in a square shape.
The present invention has the following features:
(a) The transient-grating effect (the laser to be measured is divided into four beams here) is used as the generation of the reference light in the measurement, where three of the four divided beams are used to generate the reference light. It may run in the spectral range of 200-3000 nm but the range is not so limited. Pulses with nanojoule level from the oscillator can also be measured with the method of the present invention.
(b) The apparatus according to the present invention is very simple. By using a few mirrors, two glass plates, the interference spectrum between the transient-grating signal and the pulse to be measured is obtained.
(c) In the present invention, the spectral interferometry is used to retrieve the spectral phase of the pulse. In the SRSI method, computer software programs may be used for the linear calculation, which is simple and fast. Only three-time iterative calculation is needed to obtain the spectral phase, pulse shape, and the temporal phase of the pulse.
(d) In comparison with the current technology, the present invention significantly extends the applicable range of the femtosecond pulse to be measured including the spectral range and pulse width. The measurement is fast and can be used as the single-shot measurement and for real-time monitoring.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows one embodiment of the typical optical setup according to the present invention.
FIG. 2 shows another embodiment of the typical optical setup according to the present invention.
FIG. 3 shows yet another embodiment of the typical optical setup according to the present invention.
FIG. 4( a ) is a schematic view of the plate with four equal-sized holes used in the present invention, with the light is shown to be passing through the white part of the plate. L is the distance between the center of the two neighbor holes and d is the diameter of the white hole.
FIG. 4( b ) is a schematic view of the plane reflective mirror that the first, second, and third quadrants of the mirror are coated with high reflective film, and the fourth quadrant is uncoated; the white area is uncoated, the shaded area is coated.
FIG. 5 shows the phase retrieval processes of the SRSI method for the present invention.
FIGS. 6( a ) and 6( b ) show the data measured based on the setup of the optical devices in FIG. 1 , where the pulse used has the center wavelength of 800 nm and pulse duration of 40 fs:
FIG. 6( a ) shows the interference spectrum (thin-solid line) when the time delay between the laser pulse to be test and the reference light is 0.8 ps, the spectrum of the reference light (thick-solid line), and the spectrum of the laser pulse to be test (dotted line);
FIG. 6( b ) shows the measured spectrum (solid line) and retrieved spectral phase (dotted line) of the pulse to be measured.
DETAILED DESCRIPTION OF THE INVENTION
Several embodiments of the present invention, together with the description are shown as follows, which serve to explain the principles of the invention. The drawings are only for the purpose of illustrate several embodiments of the invention and are not to be construed as limiting the invention.
The present invention uses a transient-grating light as a reference beam for the SRSI measurement. The transient-grating light is generated based on the transient-grating effect by using three beams overlapped on a transparent medium.
First, the transient-grating effect on a transparent dielectric material is used to generate a reference light. The first embodiment of the apparatus and optical setup of the present invention is shown in FIG. 1 . The optical setup includes an incident laser beam 1 ; an iris plate 2 ; a glass plate 3 which is used to introduce a suitable time delay; a plane reflective mirror 4 , of which the first, second, and third quadrants of the plane reflective mirror 4 are coated with high reflective film for light tuning; a first concave mirror coated with high reflective film 5 ; a transparent medium 6 for generation of the transient-grating light; an iris 7 which is used to select the signal light and block stray light; a second concave mirror with a reflective film 8 ; a spectrometer with high spectral resolution 9 for the measurement of the spectrum and the spectral interferometry.
In the optical setup in FIG. 1 , plate 2 has four holes with equal-diameter which are arranged in a square shape. The incident laser is divided into four beams with equal diameter by the plate 2 as shown in FIG. 4( a ) . The plane reflective mirror 4 is shown in FIG. 4( b ) , of which the first, second, and third quadrant are coated, and the fourth quadrant is not coated.
In FIG. 1 , beam 1 is large enough (for example, larger than 5 mm) to cover the plate 2 . After passing though the plate 2 , beam 1 is divided into four beams with equal beam diameter. The four laser beams located on the four corners of a square, formed a so-called “box shape” (box).
One of the four beams passes though a glass plate 3 with suitable thickness. The other three laser beams of the four beams propagate in the free air. Then, there is suitable time delay between the beam that passes through the glass plate 3 and the other three beams. Then, the four beams are reflected by the plane reflective mirror 4 . The beam that is time delayed is reflected by the non-coated quadrant of mirror 4 . The other three beams are reflected by the three coated quadrants of mirror 4 , respectively.
After reflecting by mirror 4 , the four beams are reflected onto the first concave reflective mirror 5 with a small incident angle. Then, the four beams are focused onto the glass medium 6 after mirror 5 . The three beams reflected by the coated parts are overlapped on the dielectric glass 6 both in time and space. The transient-grating signal light 12 a is generated, which is on the direction of the time delayed beam 12 b and is overlapped with it in space. By using the iris 7 , the transient-grating signal light 12 a and the beam to be measured (the beam with suitable time delay) 12 b are selected. After focusing by using a second concave reflective mirror 8 , the spectral interferometry is measured by the spectrometer 9 with high spectral resolution.
In the device of the present invention, the diameter and distance of the four holes on the plate 2 are chosen by the incident beam. The design is based on the principles that the four beams will not affect each other. The glass plate 3 is selected according to the laser wavelength which should be transparent for the glass and the dispersion is small. The thickness of the glass plate 3 should be thin if the spectral bandwidth is broad and the pulse duration is short. It will be limited by the spectral resolution of the spectrometer 9 . Based on the wavelength of the incident pulse, the plane reflective mirror 4 and the first concave reflective mirror 5 can be coated with silver, gold, aluminum, or a high reflective dielectric film. The glass medium 6 is transparent to the incident laser pulse, and preferably, has a relatively high third-order nonlinear coefficient. The thickness of glass plate 6 is usually selected to be 100-500 um. Preferably, the spectrometer 9 has a high spectral resolution.
In principle, the transient-grating effect is described by the expression (1):
I
TG
(
ω
TG
)
∝
∫
∫
ⅆ
ω
1
ⅆ
ω
2
χ
(
3
)
E
~
1
*
(
z
,
ω
1
)
E
~
2
(
z
,
ω
2
)
E
~
3
(
z
,
ω
TG
-
ω
2
+
ω
1
)
sin
c
(
Δ
k
z
(
ω
TG
,
ω
1
,
ω
2
)
L
/
2
)
2
(
1
)
where ω TG , ω 1 and ω 2 are the transient-grating light, two incident lights, respectively. Δk z (ω TG , ω 1 , ω 2 ) is the phase mismatch, L is thickness of the nonlinear dielectric material.
According to the expression (1), the generated transient-grating light own a smoother and wider spectrum than that of the incident laser pulse. As a result, the generated transient-grating light is used as the reference pulse for the SRSI measurement.
In the SRSI measurement, the generated transient-grating light (named reference light hereafter) together with the time delayed pulse to be measured are focused into a spectrometer with high spectral resolution.
The laser pulse to be measured is blocked at first to measure the spectrum of the reference light. Then, the other three beams is shielded so that no reference light is generated. The spectrum of the laser pulse to be measured is obtained by the spectrometer. By adjusting the pulse energy of the incident laser, the ratio between the reference light and the pulse to be measured is adjusted to suitable value (for example, the reference light is about 3 times stronger than the that of the pulse to be measured). Then, the spectral interference is measured and the data is saved.
By changing the thickness of the glass plate 3 , the time delay between the reference light and the pulse to be measured can be tuned. Clear interference fringes can appear at suitable time delay τ. The interference fringes increase with the increase of the time delay. It can increase the accuracy of the measurement of the spectrum and spectral phase, but it also requires a spectrometer with a higher spectral resolution. In the example, the time delay τ is adjusted to make the spectral fringes interval width at about 2 nm. The two laser beams are optimized to get the maximum modulation depth spectral interference fringes D(ω,τ) and save the data. The measured spectral interference fringes D(ω,τ) can be expressed as:
D
(
ω
,
τ
)
=
E
ref
(
ω
)
+
E
(
ω
)
ⅇ
ⅈω
τ
2
=
E
ref
(
ω
)
2
+
E
(
ω
)
2
+
f
(
ω
)
ⅇ
ⅈω
τ
+
f
*
(
ω
)
ⅇ
-
ⅈ
ω
τ
(
2
)
where ω is the angular frequency of the laser, S 0 (ω)=|E ref (ω)| 2 +|E(ω)| 2 is the sum spectrum of the reference pulse and the pulse to be measured; ƒ(ω)=E* ref (ω)E(ω) is the interference term of the two laser beams.
Subsequently, the spectrum and spectral phase of the pulse to be measured can be retrieved by using the SRSI method, and then obtain the pulse width and shape.
The calculation process of the SRSI method is shown as follows:
The initial spectral phase is set to 0, the spectrum and spectral phase of the pulse to be measured may be calculated by using Fourier transformation and iterative procedure shown in FIG. 5 , where S 0 (τ), ƒ(τ) are the Fourier transformation of the S 0 (ω) and ƒ(ω) in the time domain, respectively. To obtain the laser spectrum and spectral phase, it needs the following steps as shown in FIG. 5 :
1. Fourier transform the measured interference spectrum D(ω,τ) into the time-domain signal;
2. Extracted the time domain signals S 0 (τ), ƒ(τ) out by using a window function (such as super-Gaussian function);
3. Inverse Fourier transform S 0 (τ) and ƒ(τ) to the frequency domain, and obtain S 0 (ω) and ƒ(ω), respectively;
4. By using the following linear formulas together with S 0 (ω) and ƒ(ω), we can obtain the spectral amplitudes of both the pulse to be measured and the reference light, which are |E(ω)| and |E ref (ω)|, respectively:
|E ref (ω)|=½·(√{square root over (( S 0 (ω)+2|ƒ(ω)|))}+√{square root over (( S 0 (ω)−2|ƒ(ω)|))}) (3)
And
|E (ω)|=½·(√{square root over (( S 0 (ω)+2|ƒ(ω)|))}−√{square root over ( S 0 (ω)−2|ƒ(ω)|))}) (4)
As a result, we can obtain the laser spectra of the pulse to be measured and reference pulse, which are |E(ω)| 2 and |E ref (ω)| 2 , respectively.
5. After unwrapping the ƒ(ω), the spectral phase of the pulse to be measured can be calculated iteratively by using the following formula:
φ(ω)=φ ref (ω)+arg ƒ(ω)+ C (5)
where, φ(ω) and φ ref (ω) are the spectral phases of the pulse to be measured and that of the reference light (initial phase is assumed to be 0), C is the phase constant induced by the dispersive optical elements;
6. The obtained laser spectrum and spectral phase are Fourier transformed to time domain. Then, the pulse shape |E(t)| 2 and the pulse width of the pulse to be measured are obtained, while E(t) is the Fourier transform value of E(ω);
7. Because the spectral phase of the reference light is not exactly equal to zero, it needs a further iterative calculation step to obtain optimized laser spectrum and spectral phase. The iterative calculations are shown as follows:
(i) Based on the result obtained in the step 6 , the shape of the electric field of the reference light can be expressed as E(t)*|E(t)| 2 according to the formula (1). Through Inverse Fourier transformation of E(t)*|E(t)| 2 , the spectrum and spectral phase of the reference light are obtained, which are |E ref (ω)| 2 and φ ref (ω), respectively.
(ii) Based on the spectral phase of the reference light φ ref (ω) obtained in the above step (i) and the formula φ(ω)=φ ref (ω)+arg ƒ(ω)+C, an optimized spectral phase of the pulse to be measured can be obtained. After Fourier transformation of the new spectrum and new spectral phase of the pulse to be measured, the pulse shape and pulse width of the pulse to be measured are obtained;
(iii) After repeating above steps (i) and (ii) by several times, the optimized spectrum and spectral phase of the pulse to be measured are obtained. Finally, the corrected laser spectrum, pulse shape, and pulse duration of the pulse to be measured are obtained.
EXAMPLE
An apparatus that uses the optical setup of FIG. 1 is used, a femtosecond pulse from a commercial laser system (Coherent Inc.) is measured. The incident laser 1 to be measured have a repetition rate of 1kHz, a center wavelength of 800nm, a beam diameter of 15 mm, and a pulse energy of 10 μJ. The incident beam 1 is divided into four beams after passing through the plate 2 . The beam on the right-lower corner of the four beams passes though a glass plate 3 with 0.5 mm thickness. The other three laser beams of the four beams propagate in the free air. Then, the four beams are reflected by the plane reflective mirror 4 . The beam that passes through the 0.5 mm thickness glass plate is reflected by the non-coated quadrant of mirror 4 . The other three beams are reflected by the coated first, second, and third quadrants of mirror 4 , respectively. After being reflected by mirror 4 , the four beams are reflected onto the first concave reflective mirror 5 with a radius of 600 mm. Then, the four beams are focused onto a CaF 2 plate 6 with 150 μm thickness. The three beams reflected by the coated parts are overlapped on the CaF 2 both in time and space. The transient-grating signal light 12 a is generated, which is on the direction of the time delayed beam 12 b and is overlapped with it in space. By using an iris 7 , the transient-grating signal light 12 a and the beam to be measured 12 b (the beam with suitable time delay) are selected. After focusing by using a second concave reflective mirror 8 , the spectral interferometry is measured by the spectrometer 9 with high spectral resolution.
FIG. 6( a ) shows the interference spectrum (thin-solid line) when the time delay between the laser pulse to be test and the reference light is 0.8 ps, the spectrum of the reference light (thick-solid line), and the spectrum of the laser pulse to be test (dotted line). Based on the measured interference spectrum, the spectrum and spectral phase of the pulse to be measured are obtained by using the calculation process shown in FIG. 5 . FIG. 6( b ) shows the measured spectrum (solid line) and retrieved spectral phase (dotted line) of the pulse to be measured.
As a result of using the method of the present invention, the pulse width and shape are obtained. In the method of the present invention, only two or three reflective mirrors are used. The setup is very simple and does not need polarizer that will induce dispersion to the measured pulse. As a result, the method can be used to measure ultrashort pulse in the range of 10-300 fs at different wavelength. It can also be run in single-shot or be used for real-time monitoring of femtosecond laser pulse. Then, the spectral phase measured can be fed back to phase compensative device and optimize the femtosecond laser pulse. | Apparatuses and method for real-time measuring ultrashort pulse shape and pulse width. Transient-grating effect on a transparent optical medium is used to generate a reference beam. A black plate with four equal-sized holes divides the incoming laser beam into four beams, one of which is attenuated and introduced an appropriate time delay relative to the other three. The four laser beams pass through a concave mirror and are focused onto a nonlinear transparent optical medium. The three beams without attenuation are used to generate a transient-grating light in the transparent medium. The transient-grating light is collinear and overlapped with the fourth attenuated beam. According to the third-order nonlinear effect, the transient-grating light has a broader spectral bandwidth and more smooth spectrum phase with respect to the incident laser. By measuring the spectral interference, the spectrum and spectral phase may be retrieved by spectral interferometry. | 6 |
FIELD OF THE INVENTION
[0001] The present invention relates to music distribution, and in particular, to a method and a system for efficiently downloading, to a user terminal, musical pieces (e.g., top-ten musical pieces) included in the latest hit charts.
BACKGROUND ART
[0002] With the spread of the Internet, it has become common to conduct various transactions on the Internet, including music distribution. In the music distribution, a lot of music contents are stored in a server, and music contents requested by a user are downloaded to a terminal of that user with charge. The downloaded musical pieces can be played back by a personal computer or by a portable music playback terminal. Several music distribution sites have now been established that distribute music contents with a price of several hundreds yen per piece. Since this price is considerably lower than that of a single CD, and the music contents can be electronically stored and handled in a convenient way, it is expected that the music distribution will become ever more popular.
[0003] While various genres of music, such as classics, pop, popular ballads, latin and rock, can be downloaded from a music distribution site, users, especially young users, would exhibit a strong preference for the latest hit songs. Therefore, taking this tendency into consideration, some music distribution sites feature a list of top ten or more songs on the latest hit charts on the web.
[0004] As prior art for downloading the latest hit music, an information distribution system and a reception apparatus are disclosed in Japanese Published Unexamined Patent Application No. H11-150517. According to this system, distribution list information (hit charts list), including next distribution list information, is transmitted, along with music data, by a distribution center to a reception site, and at the reception site, a determination is made, based on the distribution list information, as to which music data should be downloaded. When the music data that is selected in this manner corresponds to songs included in the next distribution list information, at the reception site a reception waiting state is assumed, and no request is transmitted the distribution center.
[0005] Further, an also well known technique is disclosed in Japanese Published Unexamined Patent Application No. H11-312175. According to this technique, instead of downloading music data directly to a user terminal, only the information that is required for downloading to be performed is received from a music distribution server and is stored on a recording medium, such as an MD (mini disk). Subsequently, after the recording medium has been loaded into an information terminal set up in a CD shop or a convenience store and a predetermined fee has been paid, music data corresponding to the information stored on the recording medium is downloaded from the music distribution server.
[0006] Conventionally, to download music listed on the latest hit charts, a user would first identify songs that are ranked at the higher places, e.g., top ten songs, on the Web of a music distribution site, and then select a song or songs that have been newly added to the top ten list and downloads them. However, it would be troublesome for a user to check what songs are listed on the hit charts each time the user downloads a song or songs. Further, even after new song has been downloaded, if a user desires to sequentially play back, in order, the top ten songs on the hit charts, the user would have to change the music playback order, or if it is troublesome, the user would have to download the top ten songs every week.
SUMMARY OF THE INVENTION
[0007] It is, therefore, an object of the present invention to provide a method and a system for efficiently downloading music data, in a form transparent to a user, for one or more musical pieces on the latest hit charts.
[0008] It is another object of the invention to provide a method and a system for efficiently downloading only music data that are ranked at the first to predetermined places on the latest hit charts and not stored in a user's terminal.
[0009] According to a first aspect of the invention, a music distribution method for downloading, in response to a request from a user, music data for one or more musical pieces included in the latest hit charts from a server storing a lot of music data, comprising the steps of determining whether music data to be downloaded from said server are already stored in a terminal of said user, and downloading, from said server to said terminal, only music data that are not stored in said terminal, is provided.
[0010] According to a second aspect of the invention, a music distribution system comprising a server for storing a lot of music data, and means responsive to a request from a user for downloading, from said server, music data for one or more musical pieces included in the latest hit charts, wherein said downloading means including means for determining whether music data to be downloaded from said server are already stored in a terminal of said user, and means for selectively downloading, from said server to said terminal, only music data that are not stored in said terminal, is provided.
[0011] According to the preferred embodiments of the invention, music data to be downloaded are those which are ranked at the first to predetermined places on the latest hit charts and not stored in the user terminal. In addition to the music data, a latest hit charts list including places, titles and singer names is downloaded to thereby update a hit charts list of the user. Storage capacity of the user terminal can be saved by deleting, at the time of downloading, music data of musical pieces which are no longer included in the latest hit charts. The determination process in the first and the second aspects of the present invention may be performed by comparing the titles of musical pieces included in the latest hit charts list with those in the hit charts list of the user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] [0012]FIG. 1 is a schematic block diagram illustrating the configuration of a system according to the present invention.
[0013] [0013]FIG. 2 is a flowchart showing a basic flow for music distribution implemented in the system of FIG. 1.
[0014] [0014]FIG. 3 is a block diagram showing an exemplary arrangement of a user terminal to which music data are downloaded.
[0015] [0015]FIG. 4 is a flowchart showing a detailed flow of a music distribution service according to the invention.
[0016] [0016]FIG. 5 illustrates an exemplary screen for member registration.
[0017] [0017]FIG. 6 illustrates an exemplary hit charts screen that is displayed when a user logs in by inputting a user ID and a password.
[0018] [0018]FIG. 7 illustrates an exemplary hit charts list held by a user.
[0019] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] [0020]FIG. 1 is a schematic diagram showing the configuration of a system in which the present invention can be implemented. In the system of FIG. 1, multiple user terminals 10 A to 10 D (hereinafter generically referred to as user terminals 10 ) can access a music distribution server 14 across the Internet 12 . The music distribution server 14 includes a database 16 in which a lot of music data and user registration information are stored, and downloads selected music data in response to a request from a user. In addition to the music data and the user registration information, the latest hit charts list is also recorded in the database 16 , and for the music pieces included in the list (e.g., top 100), their places on the latest hit charts are associated with the music data.
[0021] A basic flow for the music distribution implemented in the system of FIG. 1 will now be explained with reference to a flowchart shown in FIG. 2. First, at step 1 , a user accesses the music distribution server 14 using, for example, a web browser to download music pieces on the latest hit charts. When the access is successful, the user requests music pieces (e.g., top ten songs) listed on the latest hit charts at step 2 . When the hit charts musical pieces are requested, the latest hit charts list stored in the database 16 of the music distribution server 14 is compared with a hit charts list stored in the terminal of the requesting user at step 3 . Finally, at step 4 , only musical pieces that are not stored in the user terminal are downloaded. While the detailed process will be described later, the comparison process at step 3 may be performed by the music distribution server 14 , the user terminal 10 , or a dedicated downloading device (not shown) set up in a shop such as a convenience store.
[0022] [0022]FIG. 3 illustrates a typical configuration of the user terminal 10 that downloads the music data on the latest hit charts in accordance with the flowchart of FIG. 2. While the exemplary configuration of FIG. 3 assumes data downloading using a personal computer, the user terminal 10 may be a personal portable terminal that can play back music, as will be described later. The user terminal 10 comprises a central processing unit (CPU) 22 , a read only memory (ROM) 24 and a dynamic random access memory (DRAM) 26 , all of which are connected to a system bus 28 . The CPU 22 , the ROM 24 and the DRAM 26 are also connected to a PCI local bus 30 via a PCI host bridge 32 . With this arrangement, the CPU 22 can access various PCI devices connected to the PCI local bus 30 . The PCI host bridge 32 also provides a high band path along which the PCI device can access the DRAM 26 .
[0023] A communication adapter (modem) 34 , a hard disk controller (HDC) 36 , an extension bus bridge 38 , an audio adapter 40 and a graphics adapter 42 are connected to the PCI local bus 30 . The communication adapter 34 is used to connect the user terminal 10 to the Internet 12 so as to facilitate the downloading of music data from the music distribution server 14 . The hard disk controller 36 is used to control a hard disk drive 46 on which an operating system, application programs and data are stored. The extension bus bridge 38 is used to connect an ISA bus 48 to the PCI local bus 30 .
[0024] As shown in FIG. 3, several user input devices can be connected to the ISA bus 48 , and in the illustrated example, a keyboard 50 , a microphone 52 and a pointing device (mouse) 54 are connected. A portable player 56 , which plays back downloaded music, may also be connected to the ISA bus 48 . If the portable player 56 is of a USB connection type, it is connected to the user terminal 10 via a USB interface (not shown). The audio adapter 40 controls audio output to a speaker 58 , and the graphics adapter 42 controls visual output to a display monitor 60 . In the user terminal 10 shown in FIG. 3, musical pieces downloaded from the music distribution server 14 can be played back through the speaker 58 or the portable player 56 . Since all the components of the user terminal 10 are well known in the art, no detailed explanations thereof will be given.
[0025] The overview of the procedure for downloading selected music data from the music distribution server 14 to the user terminal 10 has been described with reference to FIG. 2, and its details will now be described with reference to a flowchart shown in FIG. 4. The first step 70 is the same as step 1 in FIG. 2 in which a user accesses the music distribution server 14 by using a web browser such as Netscape Navigator or Internet Explorer. When the access is successful, the initial screen (homepage) of the music distribution server 14 is displayed on the display monitor 60 of the user terminal 10 . While not shown in the drawing, a member registration button and a log in button are provided on the initial screen to allow a user, who desires to download musical pieces on the latest hit charts for the first time, to perform a member registration process, and a user, who has already been registered, to log in and request downloading of the latest hit songs.
[0026] When, at step 71 , the user selects member registration, the flow proceeds to the registration step 72 where, as shown in FIG. 5, the user is prompted to input personal information such as address, name and credit card number of the user. In addition to the input of the personal information, the user can specify, in a field 80 , up to what place from the top on the latest hit charts be downloaded. Choices such as top three, top ten and top twenty may be presented by the server, or the user may specify a desired place on the charts. Adjacent to the field 80 , a price per piece may be shown for the convenience of the user. While a detailed description will be given later, even when the user specifies downloading of the top ten, not all the top ten music pieces will be downloaded; only new pieces or songs that are not stored in the user terminal are downloaded.
[0027] Since the registration works for the fields other than the field 80 are well known works performed at many sites, no detailed explanation thereof will be given. For example, it is well known in the art that when a triangular mark 81 shown at the right of the “credit card company” field is clicked, a list of credit card companies is displayed to allow the user to select one of them. When the user completes inputting the information and clicks a “completed” button 82 , the registration process ends and the information input by the user is stored in the database 16 of the music distribution server 14 . The flow then proceeds to step 73 to allow the user to log in by inputting a user ID (normally a mail address input at the time of registration is used) and a password. If the registration process at step 72 takes time and the login will not be permitted until the next access, the flow terminates after step 72 .
[0028] The user, if registered, can proceed to a process for downloading musical pieces listed on the latest hit charts by selecting login at step 73 . For a user who has selected neither the member registration nor the login, other services including an audio trial service may be provided (step 74 ). When the user who has selected login at step 73 inputs a user ID and a password following instructions on the screen, a new screen such as shown in FIG. 6 is displayed on which the user can request downloading of musical pieces listed on the latest hit charts (step 75 ).
[0029] [0029]FIG. 6 illustrates an exemplary screen titled “this week's hit charts” on which titles and singer names of top ten songs on the latest hit charts are displayed. The user can see up to, for example, the 100th place on the hit charts by operating a scroll bar 84 on the right of the screen. An audio trial button 86 and a purchase button 88 are provided to the right of each music piece. While these buttons are also provided in the existing music distribution sites, the present invention additionally provides a button 90 for collectively purchasing several music pieces ranked high on the hit charts. The user, who has specified a place on the hit charts up to which musical pieces are to be downloaded, can download only new musical pieces which the user does not have among those which are ranked at the first to the specified places, by clicking the collective purchase button 90 . Assuming that the user has specified the top ten, the process will be as follows. The same process may also be performed when the user specifies another value such as top three or top twenty.
[0030] When the user clicks the collective purchase button 90 , the flow proceeds to step 76 to compare the hit charts list held by the music distribution server 14 with that held by the user. While this comparison may be performed in either the user terminal 10 or the music distribution server 14 , it is assumed in the following that the comparison is performed in the user terminal 10 .
[0031] The music distribution server 14 has, in the database 16 , a list corresponding to the hit charts shown in FIG. 6, and the user also has a similar list in, for example, the hard disk drive 46 . An exemplary hit charts list held by the user is shown in FIG. 7. The list shown in FIG. 7 includes four entries, “ranking”, “title”, “singer” and “pointer”. The “pointer” includes a start address of an area (e.g., a portion of the hard disk drive 46 ) in which music data of a corresponding piece are stored, and the other entries are the same as those of the music distribution server 14 . The list of FIG. 7 may be used as a so-called play list. Since it is ascertained at step 75 , where the user ID and the password are input, that the user has requested the top ten musical pieces, the music distribution server 14 transmits, in response to the clicking of the collective purchase button 90 , the top ten list of the latest hit charts including their places, titles and singer names, to the user terminal 10 . This list does not include any actual music contents or music data. The user terminal 10 stores the received list in the DRAM 26 or the hard disk drive 46 , and compares, at step 76 , the titles on the received list with those on the list shown in FIG. 7 that is held by the user in order to identify musical pieces disappeared from the latest hit charts and new musical pieces to be downloaded.
[0032] At step 77 , music data of the pieces disappeared from the latest hit charts are deleted. It is preferable to delete unnecessary or old music data for the purpose of saving in storage capacity because several megabytes of storage per piece would be required for the music data even after compression. Of course, old music data may be retained if such consideration is not required.
[0033] When the musical pieces disappeared from the hit charts have been deleted, the flow proceeds to step 78 where the user terminal 10 transmits, for example, places or titles of new musical pieces to the music distribution server 14 to request downloading thereof. In response to the request, the music distribution server 14 downloads, to the user terminal 10 , the music data and attribute data (places or titles) of the specified new musical pieces. The user terminal 10 stores the received music data on the hard disk drive 46 , and stores its start address as a pointer in association with the attribute data. The pointer may be stored in the DRAM 26 . Finally, the user terminal 10 updates the hit charts list held by the user based on the latest hit charts list received at step 76 (step 79 ). This updating may be performed by writing (overwriting) titles, singers and stored pointers of the new musical pieces at the locations on the list of FIG. 7 where the old musical pieces disappeared from the latest hit charts were entered, and by rewriting the ranking column to reflect the latest hit charts. The musical pieces can be played back following the order on the hit charts by referencing the rewritten ranking column, starting playing back from “1”, and continuing in order.
[0034] If the ranking column in FIG. 7 is to be fixed to display the latest hit charts list on the display monitor 60 , the original pointer values are stored in the DRAM 26 in association with the attribute data (for the ranking, it should be of the latest hit charts) so that the “pointer” column is rewritten, as needed, for a musical piece or pieces found in both the latest hit charts list and the user's old hit charts list (i.e., musical pieces that have not been downloaded this time). Then, the “title” and “singer” columns on the user list shown in FIG. 7 are updated with corresponding contents on the latest hit charts, and the pointer values stored in the DRAM 26 are written in corresponding locations in the “pointer” column, which locations can be identified from the attribute data.
[0035] As described above, the comparison at step 76 may also be performed at the music distribution server 14 . In that case, the music distribution server 14 requests the user terminal 10 to transmit a user list such as shown in FIG. 7, in response to the clicking of the collective purchase button 90 . Receiving this request, the user terminal 10 transmits, to the music distribution server 14 , piece data on the list stored in the user terminal 10 . While the piece data may consist of titles only, it is preferable to include singer data therein to cope with a rare case in which musical pieces having the same title but performed by different singers are ranked in the hit charts. This is also true for the comparison performed by the user terminal 10 . The music distribution server 14 compares the received music data with those of the latest hit charts list held by the server 14 to identify musical pieces disappeared from the hit charts list of the user and musical pieces that are to be newly added. After this identification process, the music distribution server 14 requests the user terminal 10 to delete the musical pieces disappeared from the user's hit charts list (top ten list in this example), and the user terminal 10 deletes music data for the specified pieces in response to the request (step 77 ). After the deletion, the flow proceeds to step 78 where the music distribution server 14 downloads the latest hit charts list including places, titles and singer names (top ten list in this example) , and music data and attribute data of the musical pieces that were newly added. The updating of the user list at step 79 is performed in the same manner as when the comparison of the lists is performed by the user terminal 10 .
[0036] When the music distribution server 14 is in charge of the comparison of the lists, the server 14 may transmit, to the user terminal 10 , piece data and latest place of any musical piece remaining in the old hit charts list held by the user terminal 10 , i.e., any musical piece whose music data have not been downloaded, instead of transmitting the latest hit charts list from the music distribution server 14 to the user terminal 10 . In that case, the attribute data for the new pieces transmitted from the music distribution server 14 must include all of the places, titles and singer names. The updating of the user list at step 79 is performed in the described manner.
[0037] In the flowchart of FIG. 4, a program corresponding to the steps to be performed by the user terminal (steps 76 to 79 ) is downloaded from the music distribution server 14 to the user terminal 10 after the registration at step 72 has been completed.
[0038] While the preferred embodiments using a personal computer as the user terminal 10 have been described, the present invention may also use a personal portable terminal having a music playback function to which data can be directly downloaded. However, such a portable terminal does not have sufficient power and capacity to execute the above program, and the present invention is, therefore, preferably implemented in the following manner.
[0039] First, one or more downloading terminals (not shown) for music distribution are installed and connected to the music distribution server 14 via a network that may be any network including the Internet. While the downloading terminal may be functionally similar to the user terminal shown in FIG. 3, its hardware configuration should allow a portable terminal or a storage medium loaded therein such as MD or flash memory to be attached to the terminal. In addition to the music data, the user's hit charts list shown in FIG. 7 is also stored in this storage medium. When the user attaches his/her portable terminal or storage medium to the downloading terminal and requests downloading, the downloading terminal performs steps 76 to 79 shown in FIG. 4 in response to the request. In this embodiment, even a user who has not been registered as a member may issue a download request. For example, when the downloading terminal is installed in a convenience store, the user may merely hand his/her portable terminal or storage medium to a clerk of the store and verbally ask the clerk to download the top ten musical pieces. If the user has been registered as a member in some way, the user could input his/her user ID and password in the downloading terminal to download the musical pieces.
[0040] When the download request is received, the downloading terminal first reads a user list from the storage medium of the portable terminal, downloads the latest hit charts list from the downloading site or music distribution server 14 , compares the two lists (step 76 ), deletes data of musical pieces disappeared from the latest hit charts, if any, (step 77 ), downloads music data of new pieces to the storage medium (step 78 ), and finally updates the user list using the latest hit charts list (step 79 ). As described above, the comparison at step 76 may also be performed by the music distribution server 14 . Further, since the latest hit charts is updated periodically (e.g., every week) in the music distribution server 14 , it is not necessary to download the latest hit charts list each time step 76 is executed if the latest hit charts list is downloaded in advance from the music distribution server 14 to the downloading terminal.
[0041] By installing the downloading terminal in a convenience store, it is possible to construct a music distribution system that is very convenient for a user of a portable terminal because the member registration is not required, and payment can be done at the convenience store.
[0042] While the preferred embodiments of the present invention have been explained, it should be apparent to those skilled in the art that the present invention is not limited to these embodiments and various modifications and changes can be made. | According to the first aspect, the present invention provides a music distribution method for downloading, in response to a request from a user, music data for one or more musical pieces included in the latest hit charts from a server storing a lot of music data, comprising the steps of determining whether music data to be downloaded from said server are already stored in a terminal of said user, and downloading, from said server to said terminal, only music data that are not stored in said terminal. According to the second aspect, the present invention provides a music distribution system comprising a server for storing a lot of music data, and means responsive to a request from a user for downloading, from said server, music data for one or more musical pieces included in the latest hit charts, wherein said downloading means including means for determining whether music data to be downloaded from said server are already stored in a terminal of said user, and means for selectively downloading, from said server to said terminal, only music data that are not stored in said terminal. | 6 |
BACKGROUND OF THE INVENTION
The present invention relates to a fibrous zeolite and a preparation method thereof, and more particularly, to a fibrous zeolite which is easy to use as a functional material, can be easily adsorbed and desorbed when used as a catalyst, and can be directly used as a reinforcement material and preparation method thereof.
Scientific and industrial research into zeolite has been very active in the catalyst field since the discovery of stilbite, a natural zeolite. Currently, 34 kinds of natural zeolites are known, however industrial use thereof is limited due to pore size, crystalline structure and purity. Therefore, a powdered zeolite is synthesized and widely used as a detergent, a catalyst, an adsorbent and a moisture absorbent.
A natural or synthetic powdered zeolite can be used as a catalyst for conversion reactions of many kinds of hydrocarbons. Also, since a powdered zeolite can selectively adsorb molecules which have a predetermined form and size due to its uniform pore structure, it is called as a molecular sieve.
Several types of synthetic powdered zeolites are prepared using various methods of synthesis. Different kinds of synthetic zeolite with variable ratios of SiO 2 /Al 2 O 3 as a main component include zeolite X (U.S. Pat. No. 2,882,244), zeolite Y (U.S. Pat. No. 3,130,007), and ZSM-5 (U.S. Pat. No. 3,702,886).
As another kind of synthetic zeolite, U.S. Pat. No. 4,410,501 discloses a titanium-silicalite (hereinafter, referred to as TS-1) which substitutes titanium oxide for aluminum oxide in the conventional zeolite composed of aluminum oxide and silicon oxide. The term, TS-1 is also cited in European Patent Application Nos.267,362 and 190,609.
TS-1 has excellent selection characteristics to specific products due to the use of titanium oxide instead of aluminum oxide. That is, TS-1 has an industrially specific catalytic function in the epoxidation of unsaturated hydrocarbons; hydroxidation of aromatic hydrocarbons; oxidation of saturated hydrocarbons and alcohols; and the hydration of benzenes, phenols and alkanes. Also, TS-1 is used as a catalyst in many other reactions such as a methanation, oxidation and dehydration of aliphatic hydrocarbons containing an oxygen; polymerization of compounds having olefinic or acetylenic bonds; cracking, hydrocracking and isomerization of n-paraffins and naphthenes.
Most synthetic zeolites for such uses are prepared by hydrothermal synthesis at a high temperature (130°˜200° C.) and under high pressure (20˜80 air pressure). The synthetic zeolite thus prepared is in powder form having a particle size ranging from 0.1 μm to several μm.
A conventional zeolite is difficult to use directly because of this powder form, and therefore several methods for using conventional powdered zeolite have been disclosed. In one such method, the powdered zeolite is blended with another inactive ingredient such as alumina and made into a pellet form for use as an adsorbent in the adsorbing process. In this case, however, it is difficult to properly use the adsorption surface because the reactant's diffusion rate is reduced when the pressure differences in a packed column increase excessively.
Recently, a preparation of a film form of zeolite for use as an effective separating membrane was disclosed. By the method, a thin layer of zeolite is formed onto a support such as Teflon, a filter paper or stainless steel by using a hydrothermal method [Sano et al, J. Mater. Chem., 2, 141 (1992)]. A film form of zeolite with few surface faults such as pinhole or crack is still under study.
A method for mixing a crystalline zeolite with a polyamide fiber, and then spinning the mixture to produce a textile form of zeolite is disclosed in Japanese Patent Laid-Open Publication No. Hei 4-333,639. Also, a method for coating a zeolite onto a ceramic fiber is disclosed in Japanese Patent Laid-Open Publication No. Hei 5-131,139. However, this method is difficult to apply due to its complexity.
As described above, there is difficulty in utilizing the powdered zeolite due to the complexity of its application.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a fibrous zeolite which is easily adsorbed and desorbed when used as a catalyst, is easy to use as a functional material, and can be directly used as a reinforcement material.
Another object of the present invention is to provide a preparation method of a fibrous zeolite which is easily adsorbed and desorbed when used as a catalyst, is easy to use as functional material, and can be directly used as reinforcement material, by using a zeolite particle having a size less than 150 nm.
To achieve the first object, the present invention provides a fibrous zeolite composed of silicon oxide and titanium oxide and represented as;
xTiO.sub.2.(1-x)SiO.sub.2 (x is 0.02˜0.1).
To achieve the second object, a preparation method of a fibrous zeolite according to the present invention includes the steps of:
(i) (a) preparing at least one silicon oxide source selected from the group consisting of tetraethylorthosilicate and silica gel;
(b) mixing the silicon oxide source with at least one organic base selected from the group consisting of tetramethylammonium hydroxide, tetraethylammnonium hydroxide, tetrabutylammonium hydroxide, tetrapropylammonium bromide, pyrrolidine, propylamine, dipropylamine and tripropylamine in a molar ratio of 10:1-10:8, by agitation;
(c) diluting a hydrolyzable titanium compound with isopropyl alcohol to a final concentration of 15˜25 wt %;
(d) adding the dilution product obtained in step (c) slowly to the mixture obtained in step (b) until the molar ratio of the titanium compound and the silicon oxide source reaches 1:50˜1:10;
(e) heating the mixture obtained in step (d) to eliminate alcohol;
(f) adding 15˜50 moles of water per 1 mole of the silicon oxide source contained in the mixture to the mixture obtained in step (e);
(g) maintaining the mixture obtained in step (f) at a temperature range of 60°˜100° C. and under atmospheric pressure to obtain a mother liquor containing a zeolite crystal;
(ii) centrifuging the mother liquor obtained in step (i) to separate the zeolite crystal from the mother liquor; and
(iii) dispersing the zeolite crystal obtained in step (ii) into water in the final concentration of 0.5˜2 wt %, and evaporating water to form fibrous zeolite.
More particularly, the zeolite crystal is preferably formed when 100˜400 weight % of water based on the weight of the mother liquor obtained in step (i) is added to the mother liquor just prior to the step of centrifuging the mother liquor.
BRIEF DESCRIPTION OF THE DRAWINGS
The above objects and advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which:
FIG. 1 is a graph representing a particle size over time when zeolite crystal particles are formed according to an embodiment of the present invention;
FIG. 2A and FIG. 2B are photographs showing an X-ray diffraction patterns of a zeolite according to an embodiment of the present invention;
FIG. 3 is a graph representing a crystallinity over time when a zeolite crystal particle is formed according to an embodiment of the present invention;
FIGS. 4A and FIG. 4B are optical microphotographs (20×) of fibrous zeolites formed according to embodiments of the present invention; and
FIGS. 5A and FIG. 5B are FT-IR spectra of fibrous zeolites according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, a zeolite formed only into a powder form according to the conventional method is formed into a fibrous form. That is, unlike conventional hydrothermal synthesis at a high temperature and under high pressure, a fibrous zeolite of the present invention is formed by synthesizing a zeolite crystal having a predetermined particle size at a low temperature and under atmospheric pressure, and then forming the zeolite crystal into the fibrous form under appropriate conditions. At this time, the particle size of the zeolite crystal for formation of the fibrous form should be less than 150 nm, and preferably is less than 120 nm.
The temperature range for obtaining the particle size less than 150 nm under atmospheric pressure is 60°˜100° C., since it takes a long time to obtain a zeolite crystal at temperatures below 60° C. and the zeolite crystal is rarely formed into the fibrous form at temperature over 100° C. due to a particle size exceeding 150 nm.
The zeolite crystal should be dispersed into water in the final concentration of 0.5˜2 wt % to form a zeolite having a particle size of less than 150 nm into the fibrous form.
Finally, the zeolite crystal dispered in water is dried at about 100° C. to form the fibrous zeolite composed of silicon oxide and titanium oxide.
As a reactant for manufacturing the fibrous zeolite according to the present invention, conventional silicon oxide and titanium oxide sources can be utilized.
That is, tetraethylorthosilicate and silica gel, preferably tetraethylorthosilicate can be used as the silicon oxide source. A hydrolyzable titanium compound, such as titanium butoxide, titanium ethoxide, titanium isopropoxide, titanium tetrachloride, titanium oxychloride and so on, is used as the titanium oxide source.
The organic base to be mixed with the silicon oxide source dissolves the silicon oxide source of gel state to facilitate the reaction with the titanum oxide source. However, it is disadvantageous that the growth of the zeolite crystal is hindered at high pH level. Therefore, to obtain the zeolite crystal by a proper reaction rate, the organic base is added to the silicon oxide source in a molar ratio of 10:1˜10:8.
Hereinafter, the preparation process will be concretely explained with following examples and comparative examples, but the invention is not limited thereto.
EXAMPLE 1
1) Preparation of a zeolite crystal
90 g of tetraethylorthosilicate (TEOS) and 154 g of 20% aqueous tetrapropylammonium hydroxide (TPAOH) solution were mixed by agitation. In a separate vessel, 4.4 g of titanium butoxide was diluted with 20 g of isopropyl alcohol, and then the diluted solution is slowly dropped into the mixture of tetraethyl orthosilicate and tetrapropylammonium hydroxide. Thereafter, the reaction mixture was heated to the temperature of about 80° C. to eliminate the alcohol. 156 g of water was then added to the reaction mixture. The reaction mixture (RM) has a composition in terms of molar ratios as follows;
Ti/Si=0.03
H 2 O/Si=20
TPAOH/Si=0.35.
While maintaining atmospheric pressure and a temperature of 80° C. so that the reaction mixture can react, a mother liquor which is a solution containing particles grown after terminating the reaction was sampled over time to measure the size of the particles according to the DLS (Dynamic Light Scattering) method.
FIG. 1 is a graph representing the growth of the zeolite crystal particles over time. Referring to FIG. 1, particles having a size of about 10 nm form after 36 hours and particles having a size of 100 nm after 120 hours. The size of the particles does not increase after 120 hours. As described above, particles having size less than 150 nm can be obtained according to the present invention.
Whether the zeolite particle has crystallizability or not was judged by a diffraction pattern obtained through an X-ray diffraction analytical instrument (D/MAX, Rikagu) and the crystallinity thereof was obtained by calculating the diffraction pattern area based on the final product when crystallization was complete.
FIGS. 2A and 2B are photographs of X-ray diffraction patterns taken after 60 hours (FIG. 2A) and 120 hours (FIG. 2B) respectively, in order to judge the crystallinity of the obtained particles. As shown in the photographs, the zeolite particle presented enough crystallinity after 60 hours, and was almost fully crystallized after 120 hours.
FIG. 3 is a graph representing the crystallinity which was calculated based on the photographs of the X-ray diffraction patterns. As shown in the graph, crystallization progressed rapidly after 50 hours.
2) Formation of the fibrous zeolite
RM obtained in the step of preparation of a zeolite crystal was reacted for 70 hours to obtain the mother liquor. 300 g of water is added to the obtained mother liquor, which was then centrifuged to separate out crystal particles. The obtained crystal particles were dispersed in water in the concentration of 0.5 wt %. The dispersed solution was dried for 10 hours at 100° C. and an optical microphotograph was taken of the resultant compound.
FIG. 4A is an optical microphotograph of a zeolite formed into a fibrous form having a size of about 10˜50 mm according to the present invention.
3) heat treatment
A portion of the fibrous zeolite obtained in the step of formation of the fibrous zeolite was heated, at the rate of 10° C./min., up to 600° C., at which temperature it was maintained for 5 hours. Cracking or breaking down of the fibrous structure of the zeolite did not occur.
The heat-treated fibrous zeolite and the untreated fibrous zeolite were then subjected to FT-IR spectrum analysis. FIG. 5A is the spectrum of the zeolite which was not heat-treated and FIG. 5B is the spectrum of the heat-treated zeolite. As shown in the spectra, a characteristic peak attributed to the Si--O--Ti bond appears in the vicinity of 970 cm -1 . In the FT-IR spectrum of the heat-treated fibrous zeolite, the relative intensity at each wave number is as follows;
TABLE 1______________________________________wave number relative intensity______________________________________1220˜1230 w1080˜1110 ms965˜975 w795˜805 mw550˜560 m450˜470 ms______________________________________ *the relatives (s = strong, ms = mediumstrong, m = medium,
EXAMPLE 2
Example 1 was repeated to obtain zeolite crystal particles. The obtained crystal particles were dispersed in water in the concentration of 2 wt %, and then dried and analysed according to the same method as described in Example 1. Analysis results showed that the zeolite crystal formed into the fibrous form as shown in FIG. 4B, though it was inferior in measured characteristics when compared with a fibrous zeolite obtained from Example 1.
EXAMPLE 3-4
Example 1 was repeated twice more using 5.9 g and 14.7 g of titanium butoxide (Ti/Si molar ratios of 0.04 and 0.1, respectively) to ascertain whether the fibrous zeolite formed or not. An optical microphotograph of each compound showed the formation of the fibrous zeolite.
Comparative Example 1
90 g of tetraethyl orthosilicate and 439 g of 20% aqueous tetrapropylammonium hydroxide (TPAOH/Si=1.0) solution were mixed by agitation. In a separate vessel, 2.9 g of titanium butoxide (Ti/Si=0.02) was diluted with 60 g of isopropyl alcohol, and the diluted solution was then slowly dropped into the reaction mixture. Thereafter, the reaction mixture was heated to the temperature of about 85° C. to eliminate the alcohol. 234 g of water was then added to the reaction mixture. The reaction mixture was reacted for 100 hours under atmospheric pressure and at a temperature of 80° C. to form crystal particles.
A mother liquor containing the crystal particles was centrifuged to separate the crystal particles. The size of the crystal particles contained in the mother liquor was confirmed to be 100 nm by the DLS method. The obtained crystal particles were dispersed in water in the concentration of 50 wt %, and then dried and analysed according to the same method as described in Example 1. Analysis results showed that the zeolite crystal did not form the fibrous zeolite.
Comparative Example 2
90 g of tetraethyl orthosilicate and 439 g of 20% aqueous tetrapropylammonium hydroxide (TPAOH/Si=1.0) solution were mixed by agitation. In a separate vessel, 2.9 g of titanium butoxide (Ti/Si=0.02) was diluted with 60 g of isopropyl alcohol, and the diluted solution was then slowly dropped into the reaction mixture. Thereafter, the reaction mixture was heated to the temperature of about 85° C. to eliminate the alcohol. 234 g of water was then added to the reaction mixture. The reaction mixture was reacted for 100 hours under atmospheric pressure and at a temperature of 80° C. to form crystal particles.
1,000 g of water was added to the mother liquor containing the crystal particles and thereafter the mother liquor was centrifuged to separate the crystal particles. The size of the crystal particles contained in the mother liquor was confirmed to be 100 nm by the DLS method. The obtained crystal particles were dispersed in water in the concentration of 50 wt %, and then dried and analysed according to the same method as described in Example 1. Analysis results showed that the zeolite crystal did not form fibrous zeolite.
Comparative Example 3
90 g of tetraethyl orthosilicate and 220 g of 20% aqueous tetrapropylammonium hydroxide (TPAOH/Si=0.5) solution were mixed by agitation. In a separate vessel, 4.4 g of titanium butoxide (Ti/Si=0.03) was diluted with 60 g of isopropyl alcohol, and the diluted solution was then slowly dropped into the reaction mixture. Thereafter, the reaction mixture was heated to the temperature of about 85° C. to eliminate the alcohol. 1,300 g of water was then added to the mixture. The mixture was reacted for 90 hours under atmospheric pressure and at a temperature of 150° C. to form crystal particles, 150 nm in size.
Without performing the separation process for the crystal particles, the mother liquor was then dried for 6 hours at a temperature of 150° C. The zeolite crystal did not form fibrous zeolite.
Comparative Example 4
90 g of tetraethyl orthosilicate and 220 g of 20% aqueous tetrapropylammonium hydroxide (TPAOH/Si=0.5) solution were mixed by agitation. In a separate vessel, 4.4 g of titanium butoxide (Ti/Si=0.03) were diluted with 60 g of isopropyl alcohol, and then the diluted solution is slowly dropped into the reaction mixture. Thereafter, the reaction mixture is heated to the temperature of about 85° C. to eliminate the alcohol. 234 g of water was then added to the reaction mixture. The reaction mixture was placed in an autoclave and reacted at 150° C. to obtain a mother liquor containing particles, 120 nm in size.
The mother liquor was centrifuged to separate the crystal particles. The crystal particles were dispersed in water in the concentration of 10 wt %, and then dried and analysed according to the same method in Example 1. Analysis results showed that the zeolite crystal did not form fibrous zeolite.
Comparative Example 5
Existing ZCR-Z-Y 5.6 zeolite particle having a size of 1,000 nm (1 μm) was dispersed in water in the concentration of 10 wt %, and then dried and analysed according to the same method in Example 1. Analysis results showed that the fibrous zeolite was not formed.
TABLE 2__________________________________________________________________________ reformation conditionreaction condition.sup.1 for dryingTi/ H2O/ TPAOH/ reaction particle dens temp time fibrousSi Si Si temp. (°C.) size (nm) ity.sup.2 (°C.) (hr) growth__________________________________________________________________________example1 0.03 20 0.35 80 60 0.5 100 10 ◯2 0.03 20 0.35 80 60 2.0 100 10 ◯3 0.04 20 0.35 80 120 0.5 100 10 ◯4 0.1 20 0.35 80 110 0.5 100 10 ◯comp.example1 0.02 30 1.0 80 100 50 100 10 X2 0.02 30 1.0 80 100 50 100 10 X3 0.03 30 0.5 150 150 -- 150 5 X4 0.03 30 0.5 150 120 10 100 10 X5 -- -- -- -- 1,000 10 100 10 X__________________________________________________________________________ .sup.1 : reaction condition is based on the molar ratio. .sup.2 : density of particles is represented by weight % based on the weight of water. ◯: fibrous zeolite is formed. X: fibrous zeolite is not formed.
As described above, the fibrous zeolite formed by using zeolite crystals less than 150 nm in size according to the present invention is easy to use as a functional material, is easily adsorbed and desorbed when used as a catalyst, and can be directly used as a reinforcement material because of its fibrous form.
That is, unlike the conventional zeolite which requires a support when it is used as a catalyst, the fibrous zeolite of the present invention does not require a support and can be applied by itself.
Like this, if the zeolite is directly used as a catalyst without using support, it is easy to adsorb and desorb, thereby showing a highly reactive activity. Since the fibrous zeolite of the present invention can be directly manufactured in a mesh form, it is easy for a reactant to diffuse onto the catalyst surface.
Also, since the zeolite of the present invention is obtained in fibrous form, not only can it be used as a reinforcement material but also is capable of being spun as an other fiber, and hence, it can be manufactured into diverse forms according to the desired use. | There are disclosed a fibrous zeolite and a preparation method thereof wherein the fibrous zeolite, represented as xTiO 2 .(1-x)SiO 2 (x is 0.02˜0.1), which is easy to adsorb and desorb, and is easy to use as a functional material, and can be directly used as a reinforcement material. | 1 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to organometallic compounds for manufacturing precious-metal films or precious-metal compound films by a chemical vapor deposition process. In particular, the present invention relates to organometallic compounds for manufacturing films of ruthenium and iridium, as a precious-metal, and their compounds. In addition, it relates to a process for manufacturing precious-metal films or precious-metal compound films using these organometallic compounds.
[0003] 2. Description of the Related Art
[0004] Recently, there is a continuing need for higher performance of semiconductor devices, and for DRAMs (dynamic RAMs), researches are made with the aim of increasing their capacity from Mbit to Gbit sizes. Following this trend, technologies for densification and high integration of semiconductor devices are rapidly advanced, and in order to increase their capacity, attempts are made to improve not only their structure, but also materials used for these devices.
[0005] Under these circumstances, materials that receive recent attention as film electrode materials for DRAMs are precious metals or precious-metal oxides, and among them, ruthenium or iridium or oxides thereof. The reason is that these materials have a low resistivity, and possess superior electric properties when electrodes are produced. Consequently, these materials receive attention as becoming one of important materials for film electrodes in the future. Specifically, in the above-described DRAMs, these are examined, for example, for uses as materials for accumulating electrodes of capacitors, and are believed to be able to make a major contribution to their densification.
[0006] As a method for manufacturing precious-metal or a precious-metal film is utilized a chemical vapor deposition process (hereinafter, referred to as a CVD process) in general. This is due to, according to a CVD process, easy manufacturing of uniform films, and at the same time superiority in step coverage (ability to cover differences in level). Additionally, it is likely that a CVD process will be the mainstream of coming processes for manufacturing film electrodes which can be adapted to densify recent circuits and electronic components to a higher extent.
[0007] With respect to ruthenium, as a raw material for ruthenium films and ruthenium compound films, investigations have been recently conducted on use of bis(ethylcyclopentadienyl)ruthenium shown by the following formula. This bis(ethylcyclopentadienyl)ruthenium is a compound in which one hydrogen on each of two cyclopentadiene rings in bis(cyclopentadienyl)ruthenium (commonly called ruthenocene) is substituted with an ethyl group.
[0008] On the other hand, as a raw material for iridium films, ethylcyclopentadienyl(1,5-cyclooctadiene)iridium shown by the following formula has been investigated. This ethylcyclopentadienyl(1,5-cyclooctadiene)iridium is a compound in which one hydrogen on the cyclopentadiene ring in cyclopentadienyl(1,5-cyclooctadiene)iridium is substituted with an ethyl group.
[0009] These organic precious-metal compounds have a low melting point and are liquid at room temperature, and thus are handled easily. Additionally, these compounds have a high vapor pressure, resulting in superior efficiency in manufacturing films. Therefore, these organic precious-metal compounds are considered to be eligible as CVD raw materials.
[0010] However, while the above-described bis(ethylcyclopentadienyl)ruthenium and ethylcyclopentadienyl(1,5-cyclooctadiene)iridium have superior properties as CVD raw materials, they display poor stability in the air, and in particular tend to react with oxygen, so that reaction with oxygen takes place in the air, resulting in the formation of various derivatives, such as oxides, hydroxides, and the like, as impurities. Thus, for these organic compounds, there is a problem that slight differences in the conditions during manufacturing steps tends to exert an influence on their purity and easily result in unevenness among their manufactured lots. If films are manufactured with the use of such raw materials having a purity varied from lot to lot, then it is, of course, likely that properties of the films are also varied, depending upon their raw materials.
[0011] In addition, even if manufacturing is designed so that the product is not in contact with the air at all during the manufacturing steps, it is likely that these compounds easily undergo oxidation in the course of transportation of substrates, since oxygen gas is employed as a reaction gas in order to accelerate a film-forming reaction during the manufacturing of films.
[0012] In this case, various derivatives of these compounds act as impurities, and will exert an influence on purity and electric property of the films, and what is considered as having a greater influence is morphology such as surface roughness and the like. The influence on morphology due to these impurities is on the order of nanometers, and thus seems to be extremely small as numerical values. However, in the area of DRAMs requiring densification in these days, even such small values will be responsible for whether use can be made as electrodes.
[0013] The present invention has been achieved under the background as described above, and has an object of providing an organometallic compound for chemical vapor deposition which possesses superior properties as CVD raw materials possessed by the conventional bis(ethylcyclopentadienyl)ruthenium and ethylcyclopentadienyl(1,5-cyclooctadiene)iridium and which has high stability to oxygen.
SUMMARY OF THE INVENTION
[0014] The inventors have conducted extensive research and made investigations on organometallic compounds capable of solving the above-described problems. As a result, it has been found that the following organometallic compounds with respect to ruthenium and iridium are suitable, thereby leading to the present invention.
[0015] First, there is given an explanation of organic ruthenium compounds related to the present application. A first invention related to the present application is directed to an organometallic compound for manufacturing a ruthenium film or a ruthenium compound film by a chemical vapor deposition process, wherein the organometallic compound for chemical vapor deposition is alkylcyclopentadienyl(cyclopentadienyl)ruthenium represented by the following formula:
[0016] wherein the substituent R 1 represents any one of alkyl groups of n-propyl, iso-propyl, n-butyl, iso-butyl, and tert-butyl groups.
[0017] The organic ruthenium compounds related to the present invention have higher oxidative stability at room temperature and is not easily oxidized in the air, when compared with the conventional bis(ethylcyclopentadienyl)ruthenium. Therefore, the organic ruthenium compounds related to the present invention are not contaminated with impurities due to their partial oxidation, even if they have come in contact with the air during manufacturing and when introduced into a CVD apparatus after manufacturing. In this regard, it can be said that the organic ruthenium compounds related to the present invention are organometallic compounds allowing easier handling in manufacturing consistent films than before.
[0018] These alkylcyclopentadienyl(cyclopentadienyl)ruthenium compounds can react with oxygen and be decomposed under an atmosphere at elevated temperatures, so that these compounds will be not decomposed until they are introduced into a CVD apparatus and heated on a substrate. The rate of decomposition at high temperatures is almost the same as that of the conventional bis(ethylcyclopentadienyl)ruthenium, causing no problem in forming films.
[0019] In addition, these alkylcyclopentadienyl(cyclopentadienyl)ruthenium compounds, similarly to bis(ethylcyclopentadienyl)ruthenium, have a low melting point, resulting in easy handling, and a high vapor pressure, allowing efficient manufacturing of films, and thus are compounds having properties required as CVD raw material.
[0020] Furthermore, these alkylcyclopentadienyl(cyclopentadienyl)ruthenium compounds are synthesized with relative ease, and can be prepared by reacting bis(cyclopentadienyl)ruthenium represented by Formula 4 with an alcohol represented by formula 5.
[0021] (formula 5)
R 1 —OH
[0022] Wherein R 1 represents any one of alkyl groups of n-propyl, iso-propyl, n-butyl, iso-butyl, and tert-butyl groups.
[0023] In this reaction, it is preferable to use a catalyst, in order to promote the reaction of bis(cyclopentadienyl)ruthenium with various alcohols. As a catalyst in this case, it is preferable to employ aluminum chloride.
[0024] The following will give an explanation of organic iridium compounds related to the present application. A second invention related to the present invention is directed to an organometallic compound for manufacturing an iridium film or an iridium compound film by a chemical vapor deposition process, wherein the organometallic compound for chemical vapor deposition is alkylcyclopentadienyl(1,5-cyclooctadiene)iridium represented by the following formula:
[0025] In this formula, the substituent R 2 in the alkylcyclopentadienyl(1,5-cyclooctadiene)iridium related to the present invention is propyl or butyl group, the propyl group including n-propyl group, iso-propyl group, and the butyl group including any one of n-butyl group, iso-butyl group, and tert-butyl group. In the present invention, these substituents are specified, since the results of inventors' investigations show that alkylcyclopentadienyl(1,5-cyclooctadiene)iridium in which an alkyl group having 5 or more carbons is introduced has an increased melting point, and thus will become unfit as CVD raw material. In case of introducing an ethyl group having two carbons, on the other hand, ethylcyclopentadienyl(1,5-cyclooctadiene)iridium as mentioned above is a substance that is already known as a raw material for iridium films, and also this prior art has poor stability to the air.
[0026] These organic iridium compounds related to the present invention also have higher stability to oxygen at room temperature and do not undergo oxidation in the air, so that there is no possibility of contamination with impurities, even if they come into contact with the air before introduced into a CVD apparatus.
[0027] In addition, the organic iridium compounds related to the present invention, similarly to the conventional ethylcyclopentadienyl(1,5-cyclootadiene)iridium, have a low melting point and a high vapor pressure. Therefore, the organic iridium compounds related to the present invention are handled with ease and capable of efficiently manufacturing films. Thus, it can be said that these organic iridium compounds are compounds having properties required as CVD raw material.
[0028] Furthermore, these alkylcyclopentadienyl(1,5-cyclooctadiene)iridium compounds related to the present invention can be prepared with relative ease. That is, these compounds can be prepared by reacting bis(1,5-cyclooctadiene)iridium represented by the following formula with sodium alkylcyclopentadienide represented by the following formula:
[0029] wherein the meaning of the substituent R 2 is as specified above.
[0030] As explained above, the organic ruthenium compounds and organic iridium compounds related to the present invention can be said to be suitable substances as raw materials for ruthenium and iridium, and compound films thereof by a CVD process. A CVD process in which these organic precious-metal compounds are applied will allow stable manufacturing of films having good morphology. In consequence, as a chemical vapor deposition process related to the present invention is utilized a chemical vapor deposition process of a precious-metal or precious-metal compound film in which these organic precious-metal compounds are vaporized, transferred onto a substrate, and decomposed by heating the substrate to laminate the precious-metal.
[0031] Regarding the substrate temperature in this case, with respect to each of compounds it is preferable that temperatures are controlled to 200° C. to 300° C. to decompose an organic precious-metal compound. Also, in this CVD step, it is preferable that the inside of a reactor is under an atmosphere at reduced pressure. Reducing the pressure in a reactor can improve the uniformity of the film-thickness distribution and step-coverage (ability to cover differences in level). The preferred range of the pressure in a reactor is 140 to 1400 Pa.
[0032] As mentioned above, any organic precious-metal compound related to the present invention has a property of easily undergoing decomposition by mixing oxygen gas into the reaction system. Therefore, in a CVD step utilizing these compounds, it is preferable that an organic precious-metal compound vaporized in an atmosphere containing oxygen gas is decomposed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Preferable embodiments of the present invention will be described in conjunction with Comparative Examples. In this section, butylcyclopentadienyl(cyclopentadienyl)ruthenium and alkylcyclopentadienyl(1,5-cyclooctadiene)iridium related to the present invention were prepared, and ruthenium and iridium films were manufactured by a CVD process employing these organometallic compounds. Then, these films were compared with films manufactured with conventionally used raw materials.
[0034] A. Ruthenium Compounds
[0035] First Embodiment: 8.0 g of bis(cyclopentadienyl)ruthenium, 3.0 g of aluminum chloride, and 80 g of polyphosphoric acid were mixed. The mixed solution was heated to 100° C. under a nitrogen atmosphere, to which 3.0 g of tert-butyl alcohol was added dropwise over 30 minutes, and then the mixture was heated to 120° C. to carry out the reaction for 4 hours. After the reaction, hot water was added to the solution to remove polyphosphoric acid, and then distillation treatment gave 2.0 g of tert-butylcyclopentadienyl(cyclopentadienyl)ruthenium. Five lots of tert-butylcyclopentadienyl(cyclopentadienyl)ruthenium were prepared by this preparing method, and subjected to film production as described later.
COMPARATIVE EXAMPLE 1
[0036] For comparison with the tert-butylcyclopentadienyl(cyclopentadienyl)ruthenium prepared in the first embodiment, bis(ethylcyclopentadienyl)ruthenium was prepared. In a flask with an argon atmosphere by vacuum substitution, 200 ml of ethanol was placed, in which 25.0 g of ruthenium chloride trihydrate was dissolved, and the solution was cooled to −30° C. Then, to the solution was added 40 g of ethylcyclopentadiene, followed by 9.55 g of zinc powder (purity 99.999%, 200 meshes) in seven portions at an interval of 10 minutes. After the reaction was completed, the liquid phase was collected, from which bis(ethylcyclopentadienyl)ruthenium was extracted with hexane. As in the first embodiment, five lots of bis(ethylcyclopentadienyl)ruthenium were prepared by this preparing method, and subjected to film production.
[0037] Next, ruthenium films were manufactured by a CVD process employing five lots prepared of tert-butylcyclopentadienyl(cyclopentadienyl)ruthenium and bis(ethylcyclopentadienyl)ruthenium, and examined for properties of the ruthenium films among the lots. The conditions for manufacturing the films were as follows:
[0038] Vaporization temperature: 100° C.,
[0039] Substrate temperature: 250° C.,
[0040] Reaction chamber pressure: 200 Pa,
[0041] Carrier gas/reaction gas: argon/oxygen,
[0042] Gas flow rate: 200/200 sccm.
[0043] The manufactured films were measured for the average roughness (Rms) with an AFM (atomic force microscope) , whose results are shown in Table 1.
TABLE 1 Lot No. 1 2 3 4 5 First 1.0 nm 1.2 nm 1.0 nm 1.1 nm 1.0 nm Embodiment Comparative 2.0 nm 1.2 nm 3.0 nm 1.0 nm 2.0 nm Example 1
[0044] From these results, it has been confirmed that the ruthenium films manufactured using tert-butylcyclopentadienyl(cyclopentadienyl)ruthenium related to the first embodiment had superior roughness, regardless of the lots of the raw material. In the case of Comparative Example, bis(ethylcyclopentadienyl)ruthenium, on the other hand, the values of the surface roughness varied from lot to lot. It is believed that this is due to slight differences in the purity among the lots, because even if manufacturing have been carried out in the same steps, the time of contacting the prepared bis(ethylcyclopentadienyl)ruthenium with the air may vary delicately during the steps, or the oxygen that is the reaction gas can result in oxidation during its transportation to a substrate in manufacturing films.
[0045] Second Embodiment: 8.0 g of bis(cyclopentadienyl)ruthenium, 3.0 g of aluminum chloride, and 80 g of polyphosphoric acid were mixed. The mixed solution was heated to 100° C. under a nitrogen atmosphere, to which 4.0 g of n-propyl alcohol was added dropwise over 30 minutes, and then the mixture was heated to 120° C. to carry out the reaction for 4 hours. After the reaction was completed, hot water was added to the solution to remove the polyphosphoric acid, and then distillation treatment gave 1.8 g of n-propylcyclopentadienyl(cyclopentadienyl)ruthenium.
[0046] Five lots of n-propylcyclopentadienyl(cyclopentadienyl)ruthenium were prepared in this way, and films were manufactured under the same conditions as those of the first embodiment. As a result, it has been confirmed as in the first embodiment that films can be stably manufactured which have superiority in surface roughness, regardless of the lots of the raw material.
[0047] B. Iridium Compounds
[0048] Third Embodiment: Under an atmosphere of nitrogen gas, in 350 mL of tetrahydrofuran as a solvent was dissolved 17 g of bis(1,5-cyclooctadienechloroiridium). With cooling the solution to −80° C., a solution in which 8 g of sodium n-propylcyclopentadienide was dissolved in 35 mL of tetrahydrofuran was added. The mixed solution was then reacted at −80° C. for 30 minutes, and after that the solvent was distilled off from the reaction solution, followed by hexane extraction and vacuum distillation to give 18 g of n-propylcyclopentadienyl(1,5-cyclooctadiene)iridium. Five lots of n-propylcyclopentadienyl(1,5-cyclooctadiene)iridium were prepared by this preparing method, and subjected to film production as described later.
[0049] Forth Embodiment: Using 8.5 g of sodium iso-propylcyclopentadienide instead of sodium n-propylcyclopentadienide in the third embodiment, 20 g of iso-propylcyclopentadienyl(1,5-cyclooctadiene)iridium was prepared in an otherwise similar procedure as in the second embodiment. Also, five lots of iso-propylcyclopentadienyl(1,5-cyclooctadiene)iridium were manufactured.
[0050] Fifth Embodiment: Using 8.2 g of sodium tert-butylcyclopentadienide instead of sodium n-propylcyclopentadienide in the third embodiment, 17 g of tert-butylcyclopentadienyl(1,5-cyclooctadiene)iridium was prepared in an otherwise similar procedure to that in the second embodiment. Also, five lots of tert-butylcyclopentadienyl(1,5-cyclooctadiene)iridium were prepared.
COMPARATIVE EXAMPLE 2
[0051] For comparison to organic iridium compounds prepared in the above-described third to fifth embodiments, ethylcyclopentadienyl(1,5-cyclooctadiene)iridium was prepared. In this Comparative Example, using 8.5 g of sodium ethylcyclopentadienide instead of sodium n-propylcyclopentadienide in the first embodiment, ethylcyclopentadienyl(1,5-cyclooctadiene)iridium was prepared in an otherwise similar procedure to that in the second embodiment.
[0052] Next, iridium films were manufactured by a CVD process employing five lots of each of organic iridium compounds prepared in the third to fifth embodiments and in Comparative Example, and examined for properties of the iridium films among the lots. The conditions for manufacturing the films were set in the same conditions as in the film production carried out in the first embodiment.
[0053] The manufactured films were measured for the average roughness (Rms) with an AFM (atomic force microscope), whose results are shown in Table 2.
TABLE 2 Lot No. 1 2 3 4 5 Third 1.0 nm 1.2 nm 1.1 nm 1.0 nm 1.2 nm Embodiment Fourth 0.9 nm 1.0 nm 1.1 nm 0.9 nm 1.2 nm Embodiment Fifth 1.0 nm 1.0 nm 1.2 nm 1.1 nm 1.0 nm Embodiment Comparative 2.0 nm 1.5 nm 1.0 nm 0.8 nm 2.5 nm Example 2
[0054] From these results, it has turned out that the iridium films manufactured using the organic iridium compounds prepared in the third to fifth embodiments had superior surface roughness, regardless of the lots of the raw material. In contrast, it has been confirmed that the iridium films manufactured using the ethylcyclopentadienyl(1,5-cyclooctadiene)iridium of Comparative Example had a surface roughness varied from lot to lot, and as a result, it is difficult to stably manufacture uniform films. | A first organometallic compound is an organometallic compound for manufacturing a ruthenium film or a ruthenium compound film by a chemical vapor deposition process, wherein the organometallic compound is alkylcyclopentadienyl(cyclopentadienyl)ruthenium having a substituent of n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group. A second organometallic compound is an organometallic compound for manufacturing an iridium film or an iridium oxide film by a chemical vapor deposition process, wherein the organometallic compound for chemical vapor deposition is alkylcyclopentadienyl(1,5-cyclooctadiene)iridium having a substituent of any alkyl group of n-propyl group, iso-propyl group, or n-butyl group, iso-butyl group, tert-butyl group. | 2 |
BACKGROUND OF THE INVENTION
The present invention relates to cereal bowls for young children, and more particularly to a cereal bowl having a self-contained milk compartment separate from the cereal container, permitting the saving of time and needless spills of cereal and milk caused by young children getting their own meals.
A popular breakfast food for young and old alike is that of dry cereal with milk. This food is prepared by putting the dry cereal into a cereal bowl, and then adding milk to the cereal at the time of breakfast.
This method of preparing cereal leads to spilled cereal and milk when small children attempt to prepare their own breakfasts, particularly when unattended, as when the early-rising child's parents are asleep. If the breakfast could be prepared the night before, for example, the child could take an early breakfast without disturbing his or her parents. Of course, the milk cannot be added to the dry cereal the night before breakfast, as the cereal would become soggy.
It is therefore an object of the present invention to provide a cereal bowl with a self-contained milk container to allow the breakfast meal to be prepared well in advance of the breakfast, and which is simple enough to operate to permit young children to operate the same to dispense the milk into the cereal bowl at the appropriate time.
SUMMARY OF THE INVENTION
A self-contained cereal and milk bowl is described, comprising a cereal container suitable for holding a quantity of cereal, and a milk container separate from the cereal container. The milk container is suitable for holding a quantity of milk sufficient to mix with the cereal in the cereal container. The bowl further comprises valve means for selectively emptying the milk into the cereal container from the milk container.
In a preferred embodiment, the cereal container comprises a bowl defined by a bottom surface member and an inner sidewall member, and the milk container comprises an annular container member disposed about the periphery of the inner sidewall member.
Preferably, the valve comprises a valve member fitted in the inner sidewall between the milk container and the milk container, and an actuating rod extending between the inner sidewall member and an outer sidewall member defining an outer wall of the milk container, whereby pushing the rod actuates the valve member to release milk into the cereal container.
The cereal and milk bowl further comprises a cereal container lid for fitting over the top of the cereal container, and a milk container lid for fitting over the top of the milk container.
BRIEF DESCRIPTION OF THE DRAWING
These and other features and advantages of the present invention will become more apparent from the following detailed description of an exemplary embodiment thereof, as illustrated in the accompanying drawings, in which:
FIG. 1 is a perspective view of a cereal bowl having a self-contained milk compartment in accordance with the invention.
FIG. 2 is a side cross-sectional view of the cereal bowl of FIG. 1 taken along line 2--2 of FIG. 1.
FIG. 3 is a side partial cross-sectional view of the cereal bowl of FIG. 1 taken along line 3--3.
FIG. 4 is a partial cross-sectional view taken along line 4--4 of FIG. 2.
FIG. 5 is a partial cross-sectional view similar to FIG. 4 except that the valve connecting the milk container to the cereal container is shown in the opened condition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1-4 illustrate a cereal bowl 20 embodying the present invention. The bowl 20 comprises a cereal compartment 22 having a generally circular configuration as viewed from the top of the bowl, and defined by a bottom member 26 and an upstanding circumferential interior sidewall 28. The bowl 20 further comprises an outer circumferential sidewall 30 spaced from the interior sidewall 28, and a connecting annular surface 32 extending between the sidewalls 28 and 30, and having a slight downwardly inclination from the outer to the inner sidewall.
The inner and outer sidewalls 28 and 30 together with the surface 32 define a container 24 for milk which is separate from the cereal container 22. A milk container lid 34 shaped generally in the shape of a flat ring with sealing flanges defined at each edge thereof can be disposed over the container 24 after pouring milk into the container 24. Typically the lid 34 includes downwardly extending flanges 36 and 38 to engage the upwardly extending edges of the sidewalls 28 and 30 to seal the lid to the sidewalls and prevent leakage of milk from the container 24.
The bowl 20 further comprises a cereal container lid 40 which is press-fit into the circular opening defined by the lid 34. Thus, the bowl includes a milk container lid 34 for preventing the spillage of milk from the container 24, and a cereal container lid 40 for preventing the spillage of cereal from the container 22. The containers 22 and 24 can be filled with quantities of cereal and milk respectively, and then sealed by the lids 34 and 40 to prevent spills as the bowl 20 is subsequently handled. Moreover, the milk and cereal are separated from each other. Thus, the bowl 20 could be refrigerated for a time, typically overnight, without the cereal from becoming soggy due to immersion in milk.
The bowl 20 further comprises a valve 50 for selectively emptying the contents of the milk container 24 into the cereal container 22. The construction and operation of the valve 50 is shown more clearly in FIGS. 3-5. The valve 50 comprises an elastomeric plug 52 fitted into a circular hole 54 formed in the interior sidewall 28. A tab of elastomeric material 56 forms a hinge connecting one side of the plug 52 to the sidewall 28. A tab 58 extends from the other side of the plug 52.
The valve 50 further comprises a rod 60 which extends through a tube 63 fitted between the inner and outer sidewall members 28 and 30. The rod 60 is pressed by the bowl user to bear against the tab 58 and push the plug 52 out of the opening 54, thereby releasing the milk from the container 24 to flow into the cereal container 22. A button-like member 62 is fitted over the outer, exposed end of the rod 60. The interior end 64 of the rod 60 is tapered outwardly and is fitted through an opening 66 formed in the sidewall 28. Thus, when the plug 52 is fitted tightly into the opening 54, the tab 58 fits against the end of the rod 60, and the rod can be pressed into tight engagement with the opening 66. The ends of the tuber 65 are respectively sealed to the outer and inner sidewalls 30 and 28 to prevent milk from leaking around the rod 60.
To release milk into the cereal container 22, the button 62 of the rod 60 is pressed against the sidewall 30, thereby pushing the tab 58 inwardly and forcing the plug 52 out of the hole 54. Milk is then released into the cereal container 22, and with the cereal lid 40 removed, the cereal with milk can be eaten. Moreover, the lowest surface of the milk container in this embodiment is disposed above the lower surface 26 of the cereal container, so that the entire contents of the milk container 24 can be emptied into the cereal container.
The cereal bowl can be formed from injection-molded elements of an elastomeric material commonly used to form sealable kitchen food containers. Thus, the cereal bowl 20 is amenable to low-cost production in quantity.
It is understood that the above-described embodiments are merely illustrative of the possible specific embodiments which may represent principles of the present invention. For example, the rod 60 could be disposed just beneath the surface 32, with the tab 58 disposed downwardly over the rod end. The tube 63 would not be necessary in this alternate embodiment, since the rod would not extend through the milk container 24. Other arrangements may readily be devised in accordance with these principles by those skilled in the art without departing from the scope and spirit of the invention. | A cereal bowl having separate cereal and milk compartments, with a valve permitting emptying the contents of the milk container into the cereal container. Separate lids are provided for the milk and cereal compartments. The cereal bowl enables young children to serve their own breakfast meals without spilling milk and cereal. | 1 |
This is a divisional of co-pending application Ser. No. 08/231,544, filed Apr. 22, 1994.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to gel formulations that are blood compatible and shear sensitive. More particularly, such gel formulations comprising a polydimethylsiloxane-polyethyleneoxide copolymer gelled with dibenzylidine sorbitol in the presence of water or alcohol, are particularly useful for facilitating the separation of blood serum or plasma from the cellular portion of blood or as a thermoreversible shear-sensitive substance for use in mechanical serum separation devices.
2. Description of Related Art
Biochemical tests carried out in a clinical laboratory require use of blood serum or plasma as a sample. For preparing the sample for examination, it is frequently necessary to separate the blood serum or plasma from the solid blood components. There are known various types of blood separating compositions which are used to separate the blood components from one another.
Some blood separating compositions are formulated into thixotropic gels. For example, fumed silica to crosslink polar polyester or fatty oils into a gel or fumed silica to form a reversibly-formed network of silica particles to gel nonpolar oils.
U.S. Pat. Nos. 3,852,194, 3,920,549 and 3,997,442 disclose dibenzylidene sorbitol (DBS) gels of hydrocarbon or silicone oils that have an opaque characteristic. DBS is a gelling agent that is capable of forming a molecular network. Unlike the thixotropic gels, DBS gels of hydrocarbon or silicone oils loose all structural integrity under stress, liquefy under centrifugation, and do not reform into a solid gel. Consequently, these gels are not adequate for separating blood into liquid and solid components.
Furthermore, use of hydrophobic hydrocarbon or silicone oils in blood collection tubes is problematic. As disclosed in U.S. Pat. No. 5,247,633, blood components such as cells and fibrin clots adhere tenaciously to non-water wettable surfaces. Therefore, when the inside walls of blood collection tubes become coated with the hydrocarbon or silicone type oils of these gels, cells and clot debris will adhere, preventing clean separation of liquid and solid components of blood. Therefore, hydrocarbon and silicone type oils are not blood compatible in blood collection applications.
Whereas there are numerous publications related to gelled silicones, hydrocarbons, and polyesters there are no publications that suggest or teach that polymers containing polar ethyleneoxide moieties can be gelled with dibenzylidine sorbitol (DBS) in the presence of polar liquids yielding gels that will flow under shear forces involved in centrifugation, will not liquefy under shear, are readily gelled using water or alcohol and are compatible in blood collection applications.
SUMMARY OF THE INVENTION
The present invention is gel formulations comprising (a) a block copolymer; and (b) a gelling agent. Most desirably, gel formulations of the present invention comprise (a) a block copolymer, (b) a gelling agent; and (c) a liquid vehicle.
Preferably, gel formulations of the present invention comprise polydimethylsiloxane-polyethyleneoxide (PDMS/PEO) copolymers gelled with dibenzylidine sorbitol (DBS) in the presence of water or alcohols.
Most preferably, the gel formulations comprise:
(a) from about 50 to about 100% by weight of PDMS/PEO;
(b) from about 0.01 to about 10% by weight of DBS; and
(c) from about 0 to about 50% by weight of water or alcohol.
The gelation of oils containing water soluble moieties such as polyethyleneoxide (PEO) has not been reported and the formation of gels in the presence of water or alcohols is a surprising discovery,
The gel formulations of the present invention are useful as thermoreversible shear-sensitive substances for use in mechanical serum devices and for facilitating the separation of blood serum or plasma from the cellular portion of blood when used in blood collection tubes.
Attributes of the gel formulations of the present invention include thermoreversibility properties in that the gel can be heated to a viscous liquid state that returns to gel on cooling, retaining a substantially clear appearance and the ability to flow under shear forces involved in centrifugation. Consequently, gel formulations of the present invention do not irreversibly liquify under certain shear forces and exhibit thixotropic-like behavior and therefore may be useful as serum separation gels in blood collection applications.
Another attribute of the gel formulations of the present invention includes its use as an electrophoresis, for example in drug delivery. Water containing gels, such as PDMS/PEO, may exhibit electrical conductivity and permit inclusion of mobile electrolytes into the gel.
Another advantage of the gel formations of the present invention include its ability to maintain uniform physical and chemical properties for extended periods of time prior to use, as well as during transportation and processing of blood samples. Therefore, the components of the gel formulation will not separate under normal storage and/or use.
Most notably, the gel formulations of the present invention readily form a stable portion under normal centrifugation conditions and are relatively inert or unreactive toward the substances in the blood whose presence or concentration is to be determined. Therefore the gel formulations of the present invention are blood compatible and can be readily used in blood collection applications. As compared to hydrocarbon or silicone type oils that are typically used in blood collection applications, the gel formulations of the present invention will not attract cells and clot debris that is in blood specimens.
The gel formulations of the present invention also are thixotropic or exhibit thixotropic like properties in that the gel formulation will flow under radial stress imposed during centrifugation of blood. When used in a blood collection tube, the flowing gel reforms into a solid barrier that mechanically separates solid and liquid blood components on the basis of density when centrifugation is ceased. Since deformation of a solid barrier is essential to blood separation that resists inadvertent mechanical remixing as might occur during transport or storage of blood specimen the gel formulations of the present invention are acceptable for use in blood collection applications.
Furthermore, a desirable chemical characteristic of the gel formulations of the present invention is that it may be formed in the presence of water or alcohol to modify gel performance, such as specific gravity. A desirable physical characteristic of gel formulations of the present invention is its water white appearance.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a typical blood collection tube with a stopper.
FIG. 2 is a longitudinal sectional view of the tube of FIG. 1, taken along line 2--2, comprising a gel formulation of the present invention.
DETAILED DESCRIPTION
The present invention may be embodied in other specific forms and is not limited to any specific embodiments described in detail which are merely exemplary. Various other modifications will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the invention. The scope of the invention will be measured by the appended claims and their equivalents.
The gel formulations of the present invention preferably comprise a block copolymer; and a gelling agent. The gel formulations of the present invention most preferably, further comprise a liquid vehicle.
Most preferably, the block copolymer of the present invention is polydimethylsiloxane-polyethylene oxide (PDMS/PEO). PDMS/PEO is commercially available as SILWET® surfactant (trademark of Union Carbide, 39 Old Ridgebury Road, Danbury, Conn. 06817-0001).
SILWET surfactants are chemically unique and should not be confused with conventional polydimethylsiloxanes because they are composed of a siloxane backbone with organic polyalkyleneoxide pendants, forming chemical structures whose variations provide a wide range of useful performance characteristics.
SILWET surfactants are nonionic, concentrated, and function in aqueous and nonaqueous systems. SILWET surfactants comprise the following features: low surface tension; high wetting; good dispersing, emulsifying, lubricity; sheen, gloss enhancing; static suppressing; contribute to antifoaming; moderate profoaming; broad range of solubility and aqueous cloud points; low volatility, good thermal stability; compatible with organic surfactants and system components, and low toxicity.
SILWET surfactants are polyalkylene oxide--modified polydimethylsiloxanes. These block copolymers are of two distinct structural types. The major class is a linear polydimethylsiloxane to which polyethers have been grafted through a hydrosilation reaction. This process results in an alkyl-pendant (AP type) copolymer, in which the polyalkylene oxide groups are attached along the siloxane backbone through a series of hydrolytically stable Si--C bonds. They have the following general formula: ##STR1## where PE=--CH 2 CH 2 CH 2 O(EO) m (PO) n Z
In this formula, Me represents methyl, EO represents ethyleneoxy, PO represents 1,2-propyleneoxy, and Z can be either hydrogen or a lower alkyl radical.
The other class is a branched polydimethylsiloxane to which polyesters have been attached through condensation chemistry. This creates an alkoxy-end -blocked (AEB Type) copolymer, in which the polyalkylene oxide groups are attached at the ends of the silicone backbone through Si--O--C bonds. This linkage offers limited resistance to hydrolysis under neutral or slightly alkaline conditions, but breaks down quickly in acidic environments. They have the general formula: ##STR2## where PE═--(EO) m (PO) n R and R represents a lower alkyl group.
By varying the coefficients x, y, m, and n, a broad range of SILWET surfactants are produced. These surfactants offer unique properties and performance that are not readily achievable with conventional organic surfactants.
Particular SILWET surfactants that are useful in the gel formulations of the present invention include, but are not limited to, L720, L722 and L7500.
Most preferably, a SILWET surfactant is present in the gel formulation in an amount from about 50 to about 99.9% by weight and most preferably at about 90% per weight.
Most preferably the gelling agent of the present invention is dibenzylidene sorbitol (DBS). Since DBS is able to form a molecular network it can be successfully used to gel polydimethyl siloxane/polyethylene oxide block copolymer oils.
It is taught that DBS can be used to clarify plastics as well as to gel hydrophobic solvents and oils. The function of DBS in clarification of plastics is thought to be due to formation of small crystallites which do not scatter light as efficiently as larger crystallites, therefore yielding improved clarity.
Gel formation of oils containing polar moieties such as polyethylereoxide (PEO) in the presence of polar solvents such as water or alcohol is surprising because one skilled in the art would believe that the self association of DBS would be inhibited by competitive hydrogen bonding with polar groups. It is believed that the formation of gels of the present invention is due to the formation of a molecular network within the fluid phase induced by self association through hydrogen bonding.
Dibenzylidine sorbitol (DBS) is present in the gel formulations in an amount from about 0.01 to about 10% by weight and most preferably at about 0.25% by weight.
Optionally, a satisfactory liquid vehicle is used for admixture of the components. A satisfactory liquid vehicle such as water or alcohol may be selected. Preferably, the alcohol is selected from simple aliphatic alcohols such as methyl, ethyl or propyl alcohol, but is not limited to short chain length alcohols.
If water is used in the gel formulations, it is present in an amount from about 0 to about 50% by weight and most preferably at about 10% by weight.
If alcohol is used in the gel formulations, it is present in an amount from about 0 to about 50% by weight and most preferably at about 10% by weight.
The specific gravity of the gel formulations can be controlled by the surfactant, final concentration of DBS and any added water or alcohol.
Most preferably, the gel formulations of the present invention may be used in blood collection applications. Most notably, in blood collection tubes.
Referring to the drawings in which like reference characters refer to like parts throughout the several views thereof, FIG. 1 shows a typical blood collection tube 10, having an open end 16, a closed end 18 and a stopper 14 that includes a lower annular portion or skirt 15 which extends into and presses against the inside wall 12 of the tube for maintaining stopper 14 in place.
FIG. 2 shows the use of the gel formulations of the present invention in a typical blood collection tube. A gel formulation 20 is shown at the closed end of the tube.
A blood sample of interest can be transferred into tube 10 that comprises gel formulation 20. Tube 10 is then placed in a centrifuge and subjected to centrifugal force. This causes the gel formulation 20 to move to a point dividing the heavier and lighter fractions of the sample.
Various other modifications will be apparent to and may be readily made by those skilled in the art without departing from the scope and spirit of the invention.
The examples are not limited to any specific embodiment of the invention, but are only exemplary.
EXAMPLE I
GEL FORMATION OF PDMS-PEO COMPOSITIONS WITH WATER
Four different formulations of a water-soluble PEO-PDMS copolymer surfactant, SILWET surfactant L720, having a specific gravity of 1.04, DBS and water were mixed in glass test tubes. The tubes were heated in a sand bath held at 175°-200° C. or with a heat gun with occasional mixing while avoiding wholesale boiling. DBS was apparently soluble in certain compositions as evidenced by the disappearance of suspended particles. Full DBS solubility was not observed for other compositions.
The tubes were capped and allowed to cool in an inclined test-tube rack to form gels with a slant. Gel formation was noted by resistance to flow on tube inversion. Most compositions showed gel formation within a few hours whereas others required up to 48 hours to fully gel. Table I lists the results obtained.
TABLE I______________________________________L720 GelsWt. % DBS 90% L720 75% L720 50% L720in L720 Neat L720 10% Water 25% Water 50% Water______________________________________0.25 (-) (-) (-) (+)0.5 (+) (-) (+) (+)0.75 (+) (+) (+) (+)1.0 (+), PI (+), PI (+), PI (+), PI______________________________________ (-) = no gel formed, (+) = gel formed, PI = DBS partially insoluble
EXAMPLE II
GEL FORMATION OF PDMS-PEO COMPOSITIONS WITH ISOPROPANOL
Four different formulations of an alcohol soluble (but water insoluble) PEO-PDMS copolymer surfactant, SILWET surfactant L722, having a specific gravity of 0.99, DBS and isopropanol were mixed in glass test tubes. The tubes were heated in a sand bath held at 175°-200° C. or with a heat gun with occasional mixing while avoiding wholesale boiling. DBS was apparently soluble in certain compositions as evidenced by the disappearance of suspended particles. Full DBS solubility was not observed for other compositions.
The tubes were capped and allowed to cool in an inclined test-tube rack to form gels with a slant. Gel formation was noted by resistance to flow on tube inversion. Most compositions showed gel formation within a few hours whereas others required up to 48 hours to fully gel. Table II lists the results obtained.
TABLE II______________________________________L722 GelsWt. %DBS Neat 90% L722 75% L722 50% L722in L722 L722 10% Alcohol 25% Alcohol 50% Alcohol______________________________________0.25 (+) (+), PI (+) (+), PI0.5 (+) (+), PI (+), PI (+), PI0.75 (-) (+), I (+) (+), W1.0 (-) (+), W (+) (+), W______________________________________ (-) = no gel formed, (+) = gel formed, PI = DBS partially insoluble, W = white gel
EXAMPLE III
GEL FORMATION OF PDMS-PEO COMPOSITIONS WITH ISOPROPANOL
Four different formulations of an alcohol soluble (but water insoluble) PEO-PDMS copolymer surfactant, SILWET surfactant L7500, having a specific gravity of 0.99, DBS and isopropanol were mixed in glass test tubes. The tubes were heated in a sand bath held at 175°-200° C. or with a heat gun with occasional mixing while avoiding wholesale boiling. DBS was apparently soluble in certain compositions as evidenced by the disappearance of suspended particles. Full DBS solubility was not observed for other compositions.
The tubes were capped and allowed to cool in an inclined test-tube rack to form gels with a slant, Gel formation was noted by resistance to flow on tube inversion. Most compositions showed gel formation within a few hours whereas others required up to 48 hours to fully gel Table Ill lists the results obtained.
TABLE III______________________________________L7500 GelsWt. %DBS Neat 90% L7500 75% L7500 50% L7500in L7500 L7500 10% Alcohol 25% Alcohol 50% Alcohol______________________________________0.25 (+) (+), PI (+) (+), PI0.5 (+) (+), PI (+) (+), W0.75 (-) (+), W (+) (+)1.0 (-) (+), W (+), W (+), W______________________________________ (-) = no gel formed, (+) = gel formed, PI = DBS partially insoluble, W = white gel
EXAMPLE IV
GEL FORMATION OF PDMS-PEO COMPOSITIONS WITH ISOPROPANOL
Four different formulations of an alcohol soluble (but water insoluble) PEO-PDMS copolymer surfactant, SILWET surfactant L77, having a specific gravity of 0.99, DBS and isopropanol were mixed in glass test tubes. The tubes were heated in a sand bath held at 175°-200° C. or with a heat gun with occasional mixing while avoiding wholesale boiling. DBS was apparently soluble in certain compositions as evidenced by the disappearance of suspended particles. Full DBS solubility was not observed for other compositions.
The tubes were capped and allowed to cool in an inclined test-tube rack to form gels with a slant. Gel formation was noted by resistance to flow on tube inversion. Most compositions showed gel formation within a few hours whereas others required up to 48 hours to fully gel. Table IV lists the results obtained.
TABLE IV______________________________________L77 GelsWt. %DBS Neat 90% L77 75% L77 50% L77in L77 L77 10% Alcohol 25% Alcohol 50% Alcohol______________________________________0.25 (-) -- -- (-)0.5 (+) (-) (-) (+)0.75 -- (+) (+) (+)1.0 -- -- -- --______________________________________ (-) = no gel formed, (+) = gel formed, PI = DBS partially insoluble, W = white gel
EXAMPLE V
GEL FORMATION OF PDMS-PEO COMPOSITIONS WITH ISOPROPANOL
Four different formulations of an alcohol soluble (but water insoluble) PEO-PDMS copolymer surfactant, SILWET surfactant L7001, having a specific gravity of 0.99, DBS and isopropanol were mixed in glass test tubes. The tubes were heated in a sand bath held at 175°-200° C. or with a heat gun with occasional mixing while avoiding wholesale boiling. DBS was apparently soluble in certain compositions as evidenced by the disappearance of suspended particles. Full DBS solubility was not observed for other compositions.
The tubes were capped and allowed to cool in an inclined test-tube rack to form gels with a slant. Gel formation was noted by resistance to flow on tube inversion. Most compositions showed gel formation within a few hours whereas others required up to 48 hours to fully gel. Table V lists the results obtained.
TABLE V______________________________________L7001 GelsWt. %DBS Neat 90% L7001 75% L7001 50% L7001in L7001 L7001 10% Alcohol 25% Alcohol 50% Alcohol______________________________________0.25 (-) (-) (-) (+)0.5 (+) (+) (+) (+)0.75 (+) (+) (+) (+), PI1.0 -- -- -- --______________________________________ (-) = no gel formed, (+) = gel formed, PI = DBS partially insoluble
EXAMPLE VI
THIXOTROPIC BEHAVIOR OF PDMS-PEO GELS COMPARISON OF GEL FORMATIONS WITH WATER AS COMPARED TO GEL FORMATIONS WITH ALCOHOL
Gels formed from L720 were compared to gels of L722, L7500 and L7001. A single preparation of L720 gel was made in the proportion of 0.75 wt.% DBS and 75/25 L720 and water mixture, as listed in Table I. L722 gels were made in the proportion of 50/50 mixtures of surfactant and isopropanol at 0.25, 0.5, and 0.75 wt. % DBS, as listed in Table II. A single preparation of gel was made in the proportion of 0.75% wt. % DBS and 75/25 L7500 and isopropanol, as listed in Table III. L7001 gels were prepared as listed in Table V.
Gel slants were formed in glass tubes as described in Example I and citrated whole porcine blood was added to each tube. Blood was recalcified with 200 μL of 0.2M CaCl 2 per ml of blood and allowed to clot for 15 minutes while continuously rotating on a standard inverting hematology mixer after which the tube was centrifuged for 10 minutes in a fixed rotor hematology centrifuge. Upon centrifugation, L722 and L7500 gels migrated to the serum-air interface and L7001 gels migrated to the serum-cell interface. By contrast, the more dense L720 gel did not migrate on centrifugation and remained at the bottom of the tube. | A blood collection assembly with gel formulations including a polydimethylsiloxane-polyethyleneoxide copolymer gelled with dibenzylidine sorbitol in the presence of water or alcohol. The gel formulations are useful for facilitating the separation of blood serum or plasma from the cellular portion of blood or as a thermoreversible shear sensitive substance. | 6 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to semiconductor devices, and more particularly to copper interconnects and methods of their fabrication.
[0002] Manufacture of a semiconductor device is normally divided into two major phases. The “front end of the line” (FEOL) is dedicated to the creation of all the transistors in the body of the semiconductor device, and the “back end of the line” (BEOL) creates the metal interconnect structures, which connect the transistors to each other as well as provide power to the devices. The FEOL consists of a repeated sequence of steps that modifies the electrical properties of part of a wafer surface and grows new material above selected regions. Once all active components are created, the second phase of manufacturing (BEOL) begins. During the BEOL, metal interconnects are created to establish the connection pattern of the semiconductor device.
[0003] Semiconductor devices generally include a plurality of circuits which form an integrated circuit fabricated on a semiconductor substrate. To improve the performance of the circuits, low k dielectric materials, having a dielectric constant of less than silicon dioxide, are used between circuits as inter-layer dielectric (ILD) to reduce capacitance. Interconnect structures made of metal lines or metal vias are usually formed in and around the ILD material to connect elements of the circuits. Within a typical interconnect structure, metal lines run parallel to the semiconductor substrate, while metal vias run perpendicular to the semiconductor substrate. An interconnect structure may consist of multilevel or multilayered schemes, such as, single or dual damascene wiring structures.
[0004] There are many failure mechanisms that affect the reliability of an integrated circuit. Time Dependent Dielectric Breakdown (TDDB) is a failure mechanism where the dielectric material of the ILD breaks down as a result of long-time application of electrical stresses, such as high current density. The breakdown leads to formation of a conducting path through the dielectric material and between metal interconnects via surface diffusion of the metal interconnect structures, i.e., wires and vias. In time, the conducting path will form a short between interconnect structures causing a failure.
SUMMARY
[0005] An embodiment of the present invention discloses a method of fabrication of a semiconductor interconnect structure. The method includes the steps of providing a semiconductor structure including a first dielectric layer having a first electrically conductive structure embedded therein. A second dielectric layer is located above the first dielectric layer. The second dielectric layer and the first dielectric layer have a segment of a dielectric capping layer and a segment of a metal capping layer located therebetween such that the segment of the dielectric capping layer is horizontally planar with the segment of the metal capping layer. The segment of metal capping layer covers and abuts at least a portion of a top surface of the first electrically conductive structure. The method includes forming an opening in the second dielectric layer and the metal capping layer, thereby exposing at least a portion of the first electrically conductive structure and a portion of the dielectric capping layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 illustrates a cross-sectional view of a semiconductor device containing a back-end-of-line (BEOL) metal interconnect, in accordance with an embodiment of the present invention.
[0007] FIG. 2 is a cross-sectional view of a semiconductor device upon which the interconnect structure of FIG. 1 is be fabricated, in accordance with an embodiment of the present invention.
[0008] FIG. 3A depicts fabrication steps, in accordance with an embodiment of the present invention.
[0009] FIG. 3B depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0010] FIG. 3C depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0011] FIG. 4A depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0012] FIG. 4B depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0013] FIG. 4C depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0014] FIG. 5 depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0015] FIG. 6 depicts additional fabrication steps, in accordance with an embodiment of the present invention.
[0016] FIG. 7 illustrates a cross-sectional view of a semiconductor device containing a back-end-of-line (BEOL) metal interconnect with a second liner, in accordance with an embodiment of the present invention.
[0017] FIG. 8 depicts additional fabrication steps, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0018] Embodiments, in accordance with the present invention, recognize that metal via resistance increases with technology as the size of component features shrink. The combination of materials, and electrical properties of the materials used in fabrication of “back end of the line” (BEOL) metal interconnects creates vias with higher resistance as the size of the structural elements decrease. Metal via resistance is a combination of the resistance associated with the bulk metal, the sidewall metal, and the liner material within the metal via. Embodiments recognize that the portion of via resistance from the high resistivity liner material dominates the portion of via resistance from either the bulk metal, or the sidewall metal within the metal via. Embodiments provide a fabrication process for a metal interconnect which selectively removes the liner material at the bottom of a metal via. Removal of the high resistivity liner material at the bottom of the metal via reduces the resistance of the electrical connection between the metal via and a metal wiring landing pad.
[0019] An alternate embodiment provides a fabrication process for a metal interconnect which selectively removes the liner material at the bottom of a metal via, and replaces or adds to the original liner material with a second liner material with lower resistivity. In some embodiments, the second liner material includes conductive materials with low resistivity which provide for wettability at the bottom of the metal via during plating to prevent defects from voiding at the bottom.
[0020] Embodiments recognize that misalignment of the metal via to the metal wiring landing pad is a byproduct of registration tolerances in patterning during the fabrication process, and the opportunity for such misalignment will increase with technology as the size of component features shrink. In some embodiments, in the case of a partially landed metal via, the via is not be completely surrounded by a diffusion barrier material due to non-selectivity of a dielectric capping layer formed directly above the metal wiring landing pad. In some scenarios, without a selective diffusion barrier, ions of the bulk metal diffuse over time into the inter-layer dielectric (ILD) layer causing an electrical short due to Time Dependent Dielectric Breakdown (TDDB). Embodiments, in accordance with the present invention, provide a diffusion barrier or capping layer comprised of a dielectric component, and a metal component.
[0021] Embodiments define an interconnect structure with a bottom conductive layer, an insulating dielectric layer, a metal capping layer, and a metal conductive via, where the conductive via and bottom conductive layer are electrically connected. Fabrication methods are disclosed for etching the metal liner material from the bottom of the metal via. Reduced TDDB defects combined with reduced resistance of interconnects offer the potential to deliver superior performance and reliability for semiconductor applications in electronic devices.
[0022] Embodiments generally provide a metal interconnect between a metal wire and a metal via with reduced resistance surrounded by a diffusion barrier permitting reproducible and manufacturable designs. Detailed description of embodiments of the claimed structures and methods are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the claimed structures and methods that may be embodied in various forms. In addition, each of the examples given in connection with the various embodiments is intended to be illustrative, and not restrictive. Further, the Figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the methods and structures of the present disclosure.
[0023] References in the specification to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
[0024] For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, and derivatives thereof shall relate to the disclosed structures and methods, as oriented in the drawing Figures. The terms “on”, “over”, “overlying”, “atop”, “positioned on”, or “positioned atop” mean that a first element, such as a first structure, is present on a second element, such as a second structure, wherein intervening elements, such as an interface structure may be present between the first element and the second element. The terms “direct contact”, “directly on”, or “directly over” mean that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intermediary conducting, insulating or semiconductor layers at the interface of the two elements. The terms “connected” or “coupled” mean that one element is directly connected or coupled to another element, or intervening elements may be present. The terms “directly connected” or “directly coupled” mean that one element is connected or coupled to another element without any intermediary elements present.
[0025] Referring now to the Figures, FIG. 1 illustrates a cross-sectional view of a semiconductor device containing a back-end-of-line (BEOL) metal interconnect, i.e. interconnect structure 100 , in accordance with an embodiment of the present invention. Interconnect structure 100 includes lower interconnect level 202 and upper interconnect level 210 which are separated, in part, by a capping layer comprised of metal capping layer 312 and dielectric capping layer 314 . In this embodiment, lower interconnect level 202 is located above a semiconductor substrate (not shown) including one or more semiconductor front-end-of-line (FEOL) devices. Lower interconnect level 202 includes dielectric layer 204 , and an embedded conductor comprised of liner material 206 , and conductive material 208 . Liner material 206 acts as a diffusion barrier separating conductive material 208 from dielectric layer 204 . As such, together, liner material 206 and conductive material 208 constitute an electrically conductive structure embedded in dielectric layer 204 . Upper interconnect level 210 includes a second dielectric layer, i.e., dielectric layer 416 , which has two via openings located therein for via 110 , and via 120 . The two via openings for vias 110 and 120 , each expose a portion of conductive material 208 in lower interconnect level 202 . The two via openings for vias 110 and 120 are filled with liner material 418 and conductive material 622 , which forms an electrical connection between lower interconnect level 202 and upper interconnect level 210 . As such, vias 110 and 120 are seen as a type of electrically conductive structures. Liner material 418 acts as a diffusion barrier separating conductive material 622 from dielectric layer 416 . Although the structure shown in FIG. 1 illustrates an interconnect having two vias, other embodiments include any number of such vias in dielectric layer 416 . In some embodiments, one or more such vias expose other conductive regions embedded in dielectric layer 204 .
[0026] In accordance with an embodiment of the present invention, interconnect structure 100 includes a partially landed via, via 110 , above conductive material 208 . Via 110 is partially landed on conductive material 208 such that only a portion of the bottom via surface is directly on conductive material 208 . A second portion of the bottom via surface of via 110 is directly on dielectric capping layer 314 . A first portion of the sidewall of via 110 is connected to dielectric capping layer 314 , and a second portion of the sidewall of via 110 is connected to metal capping layer 312 . In some embodiments, the sidewall of via 110 include liner material 418 . Both metal capping layer 312 and dielectric capping layer 314 act as a diffusion barrier separating conductive materials 208 and 622 from dielectric layers 204 and 416 . In other words, both metal capping layer 312 and dielectric capping layer 314 inhibit the migration of metals or other elements from conductive materials 208 and 622 to dielectric layers 204 and 416 .
[0027] In accordance with an embodiment of the present invention, both vias 110 and 120 are constructed with portions of metal liner material 418 selectively removed from the bottom of each via. In some embodiments, portions of conductive material 208 directly under the removed portions of metal liner material 418 are selectively removed. In some embodiments, removal of a portion of conductive material 208 ensures that metal liner material 418 is completely removed. In some embodiments, removal of a portion of conductive material 208 results in a texturing of the bottom via surface to aid adhesion of conductive material 622 . Conductive material 622 fills in vias 110 and 120 , and directly contacts conductive material 208 to reduce or minimize via resistance. Removal of portions of metal liner material 418 provides a reduction in overall via resistance.
[0028] In some embodiments, above upper interconnect level 210 includes upper wiring layers (not shown), or escape wiring leading to the surface above interconnect structure 100 . In some embodiments, such above the upper wiring layers, are protective layers (not shown), such as oxides, nitrides, and polyimide films, as are standard in semiconductor manufacture.
[0029] FIGS. 2-6 depict an embodiment for fabricating interconnect structure 100 with vias 110 and 120 . FIG. 2 is a cross-sectional view of a semiconductor device upon which the interconnect structure of FIG. 1 is fabricated, in accordance with an embodiment of the present invention. In some embodiments, lower interconnect level 202 is located above a semiconductor substrate (not shown) including one or more semiconductor front-end-of-line (FEOL) devices. In some embodiments, the semiconductor substrate includes an electrically semiconducting material, an insulating material, a conductive material, devices, or structures made of these materials or any combination thereof (e.g., a lower level of an interconnect structure). In certain embodiments, the semiconductor substrate is comprised of a semiconducting material, such as Si, SiGe, SiGeC, SiC, Ge alloys, GaAs, InAs, InP, and other compound semiconductors, or organic semiconductors. In some embodiments, in addition to the above listed semiconducting materials, the semiconducting material includes a layered semiconductor, such as, for example, Si/SiGe, Si/SiC, SOIs, or silicon germanium-on-insulators (SGOIs). In some embodiments, these semiconductor materials form a device, devices, or structures, which are either discrete or interconnected, or a combination thereof.
[0030] In certain embodiments, the semiconductor substrate includes one or more semiconductor devices, such as complementary metal oxide semiconductor (CMOS) devices or other field effect transistors (FETs), strained silicon devices, carbon-based (carbon nanotubes and/or graphene) devices, phase-change memory devices, magnetic memory devices, magnetic spin switching devices, single electron transistors, quantum devices, molecule-based switches, and other switching or memory devices that can be part of an integrated circuit formed therein. In other embodiments, the semiconductor substrate includes an electrical insulating material, such as an organic insulator, an inorganic insulator, or a combination thereof. In some embodiments, the semiconductor substrate includes electrically conducting material, for example, polysilicon, an elemental metal, an alloy including at least one elemental metal, a metal silicide, a metal nitride, etc., or combinations thereof including multilayers.
[0031] In the illustrative example of FIG. 2 , lower interconnect level 202 includes dielectric layer 204 , and a conductor embedded therein comprised of liner material 206 , and conductive material 208 . In some embodiments, dielectric layer 204 of lower interconnect level 202 is any ILD layer including inorganic dielectrics or organic dielectrics, and is either porous or non-porous, or a combination thereof. Examples of suitable dielectrics include, but are not limited to, SiC, Si 3 N 4 , SiO 2 , a carbon doped oxide, SiC(N,H), a low-K dielectric, or multilayers thereof. In some embodiments, dielectric layer 204 is formed over the surface of the semiconductor substrate using an appropriate deposition technique including, but not limited to, physical vapor deposition (PVD), plasma assisted chemical vapor deposition (PACVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), low pressure chemical vapor deposition (LPCVD), atomic layer deposition (ALD), chemical solution deposition (such as spin coating), or evaporation. In some embodiments, the thickness of dielectric layer 204 varies depending on the dielectric material used and the number of dielectric layers within lower interconnect level 202 . For typical interconnect structures, dielectric layer 204 has a thickness from about 100 nm to 450 nm.
[0032] In some embodiments, conductive material 208 of lower interconnect level 202 forms a conductive region or feature embedded in dielectric layer 204 . In some embodiments, the conductive region or feature is formed by conventional damascene patterning or subtractive etch patterning utilizing lithographic, etching, and deposition processes. For example, a photoresist layer is applied to the surface of dielectric layer 204 . The photoresist layer is exposed to a desired pattern of radiation, and developed utilizing a conventional resist developer. The patterned photoresist layer is used as an etch mask to transfer the pattern into dielectric layer 204 . The etched region of dielectric layer 204 is then filled with conductive material 208 to form the conductive region or feature. Conductive material 208 includes, but is not limited to, polysilicon, a conductive metal, an alloy of two or more conductive metals, a conductive metal silicide, or any combination of two or more of the foregoing materials. In some embodiments, conductive material 208 is comprised of one or more of Cu, Al, W, Ti, TiN, Cu alloy (such as AlCu), or any other useful conductive material or alloy(s). Conductive material 208 is deposited into the etched region of dielectric layer 204 using an appropriate deposition technique including, but not limited to, sputter deposition, ALD, CVD, PVD, PECVD, electrochemical deposition (ED), electroplating, or other deposition techniques. In some embodiments, after deposition, a conventional planarization process, such as chemical mechanical polishing (CMP), is used to provide a structure in which conductive material 208 has an upper surface that is substantially coplanar with the upper surface of dielectric layer 204 .
[0033] Embodiments provide for separation of conductive material 208 from dielectric layer 204 by a diffusion barrier layer, such as liner material 206 . In some embodiments, liner material 206 includes, but is not limited to, one or more of: Ta, TaN, Ti, TiN, Ru, RuTaN, RuTa, W, WN, or any other material that serves as a barrier to prevent a conductive material from diffusing into a dielectric material layer. In some embodiments, liner material 206 is formed by a deposition process including, but not limited to, ALD, CVD, PVD, PECVD, ED, sputtering, or plating. In some embodiments, liner material 206 also includes a bilayer or multi-layer structure that includes a lower layer of a metallic nitride, such as TaN, and an upper metallic layer, such as Ta. In some embodiments, the thickness of liner material 206 varies depending on the exact means of the deposition process and the material employed. Typically liner material 206 has a thickness from about 4 nm to about 40 nm, with a thickness from about 7 nm to about 20 nm being more typical.
[0034] FIG. 3A depicts fabrication steps, in accordance with an embodiment of the present invention. After forming the at least one conductive feature comprising conductive material 208 within dielectric layer 204 , a capping layer is selectively formed on the surface of conductive material 208 of lower interconnect level 202 . Metal capping layer 312 is formed by a conventional deposition process including, but not limited to, CVD, ALD, or electroless plating. The various deposition conditions are optimized to provide selective deposition to the conductive surface of conductive material 208 without utilizing a mask. In some embodiments, metal capping layer 312 is any suitable metallic capping material including, but not limited to, Co, Ru, W, Ta, Ti, P, Rh, and any alloy or combination thereof. Metal capping layer 312 provides a diffusion barrier between conductive material 208 of lower interconnect level 202 and dielectric layer 416 of upper interconnect level 210 , as shown in FIG. 1 .
[0035] FIG. 3B depicts additional fabrication steps, in accordance with an embodiment of the present invention. After forming metal capping layer 312 , a second capping material, dielectric capping layer 314 is blanket deposited over the surface of both dielectric layer 204 and metal capping layer 312 . In some embodiments, dielectric capping layer 314 is deposited on dielectric layer 204 and metal capping layer 312 using an appropriate deposition technique (discussed above). In some embodiments, dielectric capping layer 314 is any suitable dielectric capping material including, but not limited to, SiC, Si 4 NH 3 , SiO 2 , or multilayers thereof. Dielectric capping layer 314 provides a diffusion barrier between conductive material 622 of upper interconnect level 210 , as depicted and described in FIG. 1 , and dielectric layer 204 of lower interconnect level 202 . Embodiments provide that dielectric capping layer 314 has a dielectric constant higher than dielectric layer 204 of lower interconnect level 202 , and dielectric layer 416 of upper interconnect level 210 , as depicted and described in FIG. 1 .
[0036] FIG. 3C depicts additional fabrication steps, in accordance with an embodiment of the present invention. In some embodiments, after deposition, a conventional planarization process, such as CMP, is used to provide a structure in which both metal capping layer 312 and dielectric capping layer 314 have an upper surface that is substantially coplanar with the upper surface of lower interconnect level 202 . After CMP, metal capping layer 312 and dielectric capping layer 314 have a thickness from about 15 nm to about 55 nm, with a thickness from about 25 nm to about 45 nm being more typical. In some embodiments, the thickness of the capping layer materials varies depending on the exact means of the deposition process as well as the materials employed.
[0037] FIG. 4A depicts additional fabrication steps, in accordance with an embodiment of the present invention. Next, upper interconnect level 210 is formed by depositing dielectric layer 416 on the upper exposed surfaces of metal capping layer 312 and dielectric capping layer 314 . In some embodiments, dielectric layer 416 is the same or different dielectric material as that of dielectric layer 204 of lower interconnect level 202 . In some embodiments, dielectric layer 416 is comprise dielectric material including, but not limited to: SiC, Si 3 N 4 , SiO 2 , a carbon doped oxide, SiC(N,H), a low-K dielectric, or multilayers thereof. In various embodiments, dielectric layer 416 is Si 3 N 4 with a typical thickness of about 100 nm to 450 nm. A person of ordinary skill in the art will recognize that CMP steps may be inserted after the dielectric deposition process to planarize the surface of dielectric layer 416 . In some embodiments, CMP utilizes a combination of chemical etching and mechanical polishing to smooth the surface and even out any irregular topography.
[0038] Using a conventional lithography process, an etch mask (not shown) is deposited over dielectric layer 416 , and then patterned to create openings in the etch mask. The openings define at least two portions of dielectric layer 416 to be removed, which form openings for vias 110 and 120 of upper interconnect level 210 , in accordance with an embodiment of the present invention. FIG. 4A illustrates vias 110 and 120 with an outline surrounding the via openings in dielectric layer 416 . Dielectric layer 416 is etched down to metal capping layer 312 and dielectric capping layer 314 forming vias 110 and 120 therein. A portion of the top surface of metal capping layer 312 and a portion of the top surface of dielectric capping layer 314 are exposed at the bottom of via 110 . A second portion of the top surface of metal capping layer 312 is exposed at the bottom of via 120 . In some embodiments, the etching used in transferring the via pattern comprises a dry etching process, a wet chemical etching process or a combination thereof. The term “dry etching” is used herein to denote an etching technique such as reactive-ion etching (RIE), ion beam etching, plasma etching, or laser ablation. In the illustrative embodiment, vias 110 and 120 are formed by employing an RIE process. RIE uses chemically reactive plasma, generated by an electromagnetic field, to remove various materials. A person of ordinary skill in the art will recognize that the type of plasma used will depend on the material being removed. In some embodiments, the patterned etch mask is not removed at this point. In other embodiments, the patterned etch mask is removed at this point.
[0039] FIG. 4B depicts additional fabrication steps, in accordance with an embodiment of the present invention. Using a conventional etching process, one or more portions of metal capping layer 312 are exposed at the bottom of vias 110 and 120 . Such etching continues until at least a part of the openings for vias 110 and 120 have reached conductive material 208 . As such, post etching, metal capping layer 312 is covering only a portion of the top-most surface of conductive material 208 In some embodiments, the etching used to remove the one or more portions of metal capping layer 312 comprise a dry etching process, a wet chemical etching process or a combination thereof. Methods are employed that selectively etch metal surfaces, such as metal capping layer 312 , and do not substantially etch the surrounding dielectric, such as dielectric layers 204 and 416 , and dielectric capping layer 314 . A metal etch process that is selective to etching metal capping layer 312 , and not etching the underlying conductive material 208 is employed. For example, when removing metal capping layer 312 comprising one of Co, Ti, and CoWP, the wet etch process comprises two etchants. A first etchant comprises a dilute nitric acid solution with typical concentrations of 20 to 60 percent volume per volume (% v/v). A second etchant comprises a mixture of hydrogen peroxide with typical concentrations of 3 to 15 percent weight per weight (% w/w), and a quaternary ammonium compound with typical concentrations of 0.2 to 1.5% w/w.
[0040] FIG. 4C depicts additional fabrication steps, in accordance with an embodiment of the present invention. In some embodiments, liner material 418 is deposited on the exposed portions of dielectric layer 416 , such as the top surface and the sidewalls of vias 110 and 120 , the exposed portions of conductive material 208 and liner material 206 at the bottom of vias 110 and 120 , the exposed portions of dielectric capping layer 314 at the bottom of via 110 , and the exposed sidewall portions of metal capping layer 312 in vias 110 and 120 . In some embodiments, liner material 418 includes, but is not limited to, Ta, TaN, Ti, TiN, Ru, RuN, RuTa, RuTaN, W, WN, Co, CoW, Mn, MnO, a combination comprising two or more of the foregoing materials, or any other material that serves as a barrier to prevent a conductive material from diffusing through a dielectric material. Combinations of these materials are also contemplated to form a multilayered stacked diffusion barrier layer. Liner material 418 is formed utilizing an appropriate deposition technique, such as ALD, CVD, PECVD, PVD, sputtering, chemical solution deposition, or plating. In some embodiments, the thickness of liner material 418 varies depending on the number of material layers within the barrier layer, the technique used in forming the same, as well as the material of the diffusion barrier layer itself. In various embodiments, liner material 418 is Ta with a typical thickness of about 5 nm to about 50 nm.
[0041] FIG. 5 depicts additional fabrication steps, in accordance with an embodiment of the present invention. In one embodiment, horizontal portions of liner material 418 are selectively removed from locations 510 , 520 , and 530 . Location 510 indicates portions of liner material 418 above the top surface of dielectric layer 416 that have been removed. Location 520 indicates portions of liner material 418 above the top surface of dielectric capping layer 314 and conductive material 208 that have been removed, thereby exposing portions of dielectric capping layer 314 and conductive material 208 at the bottom of via 110 . Turning now to the discussion of the elements seen in both FIGS. 5 and 6 , the portions of liner material 418 that have been removed from location 520 become the location where the two bottom portions of via 110 come into contact with dielectric capping layer 314 and conductive material 208 . As such, the bottom portions of via 110 are seen to be in contact with a portion of dielectric capping layer 314 and a top surface of conductive material 208 that have been exposed. Therefore, a bottom portion of via 110 is located over a portion of dielectric capping layer 314 , while another bottom portion of via 110 is in electrical contact with conductive material 208 .
[0042] Returning now to the discussion of FIG. 5 , location 530 includes portions of liner material 418 above the top surface of the exposed portion of conductive material 208 at the bottom of via 120 . The selective removing process includes, but is not limited to, an ion-sputtering process with a gas resource including, but not limited to: Ar, He, Xe, Ne, Kr, Rn, N2 or H2. The ion-sputtering process is the removal of material by atom bombardment, and works by line of sight allowing the horizontal surfaces to be removed and leaving the vertical surfaces with minimal sidewall removal. For example, an Ar sputtering process is utilized to selectively remove portions of liner material 418 using a conventional Ar sputtering process that is used in interconnect technology.
[0043] In some embodiments, subsequent to the removal of the portions of liner material 418 , the etching process removes a portion of the exposed metal from the surface of conductive material 208 , thereby producing a new exposed metal surface at a position below the level of dielectric layer 204 and to provide better adhesion of conductive material 622 to the surface of conductive material 208 , as shown in at least FIGS. 6 and 7 . Processes for etching the metal, however, should not roughen the metal surface so much as to create pits or cavities deep enough to retain pockets of moisture during subsequent process operations.
[0044] FIG. 6 depicts additional fabrication steps, in accordance with an embodiment of the present invention. In some embodiments, conductive material 622 is formed over the sidewalls and bottoms of vias 110 and 120 , as well as the surface of dielectric layer 416 using CVD, or other appropriate deposition techniques (discussed above). In some embodiments, conductive material 622 comprises the same or different conductive material as that of conductive material 208 . In some embodiments, conductive material 622 comprises a metal or metal alloy including, but not limited to, Cu, Al, W, Ti, Ta, alloys, or any other useful conductive material or combinations thereof. Conductive material 622 , liner material 206 , and conductive material 208 are chosen to minimize electrical resistance between them. In one embodiment, conductive material 622 is deposited as plated Cu. In some embodiments, in the case of plated Cu, an initial seed or catalyst layer is deposited prior to plating. The optional seed layer is comprised of a metal or metal alloy including, but not limited to, Ru, TaRu, TaN, Ir, Rh, Pt, Pd, Co, Cu and alloys thereof. In some embodiments, the deposition is followed by a CMP process to remove excess conductive material 622 and liner material 418 above the surface of dielectric layer 416 , and to confine conductive material 622 to vias 110 and 120 formed in dielectric layer 416 .
[0045] Additional wiring layers (not shown) are fabricated above interconnect structure 100 using conventional damascene patterning or subtractive etch patterning utilizing lithographic, etching and deposition processes such that no further explanation is required herein for those of skill in the art to understand the invention. One skilled in the art will recognize that additional cleaning processes may be necessary before creating the additional wiring layers. In some embodiments, a passivation layer, a dielectric capping layer, or a protective coating, such as SiN or SiO 2 , is deposited (not shown) on surface wires (not shown) to protect the metal surface from environmental conditions. In some embodiments, a polyimide layer is deposited (not shown) on top of the passivation layer with openings for solder connections.
[0046] FIG. 7 illustrates a cross-sectional view of a semiconductor device containing a back-end-of-line (BEOL) metal interconnect with a second liner, in accordance with an embodiment of the present invention. Interconnect structure 700 includes lower interconnect level 202 and upper interconnect level 210 which are separated, in part, by a capping layer comprised of metal capping layer 312 and dielectric capping layer 314 . In some embodiments, lower interconnect level 202 is located above a semiconductor substrate (not shown) including one or more semiconductor front-end-of-line (FEOL) devices. Lower interconnect level 202 includes dielectric layer 204 , and an embedded conductor comprised of liner material 206 , and conductive material 208 . Liner material 206 acts as a diffusion barrier separating conductive material 208 from dielectric layer 204 . Upper interconnect level 210 includes a second dielectric layer, i.e., dielectric layer 416 , which has two via openings located therein for via 110 , and via 120 . The two via openings for vias 110 and 120 , each expose a portion of conductive material 208 in lower interconnect level 202 . The two via openings for vias 110 and 120 are filled with liner material 418 , liner material 824 , and conductive material 622 , which forms an electrical connection between lower interconnect level 202 and upper interconnect level 210 . Liner material 418 acts as a diffusion barrier separating conductive material 622 from dielectric layer 416 . Although the structure shown in FIG. 7 illustrates an interconnect having two vias, in other embodiments, any number of such vias in dielectric layer 416 exist. In such embodiments, certain of those vias expose other conductive regions embedded in dielectric layer 204 .
[0047] In accordance with an embodiment of the present invention, interconnect structure 700 includes a partially landed via, via 110 , above conductive material 208 . Via 110 is partially landed on conductive material 208 such that only a portion of the bottom via surface is directly on conductive material 208 . A second portion of the bottom via surface of via 110 is directly on dielectric capping layer 314 . A first portion of the sidewall of via 110 is connected to dielectric capping layer 314 , and a second portion of the sidewall of via 110 is connected to metal capping layer 312 . In some embodiments, the sidewall of via 110 includes liner material 418 . Both metal capping layer 312 and dielectric capping layer 314 act as a diffusion barrier separating conductive materials 208 and 622 from dielectric layers 204 and 416 .
[0048] In accordance with an embodiment of the present invention, both vias 110 and 120 are constructed with portions of metal liner material 418 selectively removed from the bottom of each via. In some embodiments, portions of conductive material 208 directly under the removed portions of metal liner material 418 are selectively removed. In some embodiments, removal of a portion of conductive material 208 ensures that metal liner material 418 is completely removed. In some embodiments, removal of a portion of conductive material 208 textures the bottom via surface to aid the adhesion of conductive material 622 . Conductive material 622 fills in vias 110 and 120 , and directly contacts conductive material 208 to reduce or minimize via resistance. Removal of portions of metal liner material 418 provides a reduction in overall via resistance.
[0049] In accordance with an alternate embodiment of the present invention, both vias 110 and 120 are constructed with a low resistivity wetting layer comprised of liner material 824 . In various embodiments, liner material 824 serves as a wetting agent for reducing voiding during deposition of conductive material 622 , and has the property of low resistivity which reduces the overall via resistance of vias 110 and 120 . The layer comprising liner material 824 visible on the bottom surface of vias 110 and 120 above conductive material 208 as illustrated in FIG. 7 is a unique structural signature identifying the fabrication method used for making interconnect structure 700 .
[0050] In some embodiments, above upper interconnect level 210 include upper wiring layers (not shown), or escape wiring leading to the surface above interconnect structure 700 . In some embodiments, above the upper wiring layers, there are protective layers (not shown), such as oxides, nitrides, and polyimide films, as are standard in semiconductor manufacture.
[0051] FIG. 8 depicts additional fabrication steps, in accordance with an embodiment of the present invention. In some embodiments, subsequent to the etching of liner material 418 as depicted and described in further detail with respect to FIG. 5 , liner material 824 is deposited on the exposed portions of the top surface of dielectric layer 416 , the exposed portions of conductive material 208 at the bottom of vias 110 and 120 , the exposed portion of liner material 206 at the bottom of via 110 , the exposed portions of dielectric capping layer 314 at the bottom of via 110 , and the exposed sidewall portions of liner material 418 in vias 110 and 120 . In some embodiments, liner material 824 includes, but is not limited to, Cu, Ru, Co, or a combination comprising two or more of the foregoing materials, or any other material that serves as a wetting agent for reducing voiding during deposition of conductive material 622 (shown and described in at least FIGS. 6 and 7 ), and has the property of low resistivity, typically less than 100 micro-ohm centimeters. Liner material 824 is formed utilizing an appropriate deposition technique, such as ALD, CVD, PECVD, or PVD. In various embodiments, liner material 824 is Co with a typical thickness of about 5 nm to about 50 nm. The layer comprising liner material 824 visible on the bottom surface of vias 110 and 120 above conductive material 208 as illustrated in FIG. 8 is a unique structural signature identifying the fabrication method used for making interconnect structure 700 .
[0052] Having described embodiments for a metal interconnect comprised of a via with reduced resistance and methods of fabrication removing the metal liner at the bottom of the via (which are intended to be illustrative and not limiting), it is noted that modifications and variations may be made by persons skilled in the art in light of the above teachings. It is, therefore, to be understood that changes may be made in the particular embodiments disclosed which are within the scope of the invention as outlined by the appended claims.
[0053] In certain embodiments, the method as described above is used in the fabrication of integrated circuit chips. The fabrication steps described above may be included on a semiconductor substrate consisting of many devices and one or more wiring levels to form an integrated circuit chip.
[0054] The resulting integrated circuit chip(s) can be distributed by the fabricator in raw wafer form (that is, as a single wafer that has multiple unpackaged chips), as a bare die, or in a packaged form. In the latter case the chip is mounted in a single chip package (such as a plastic carrier, with leads that are affixed to a motherboard or other higher level carrier) or in a multichip package (such as a ceramic carrier that has either or both surface interconnections or buried interconnections). In any case, the chip is then integrated with other chips, discrete circuit elements, and/or other signal processing devices as part of either (a) an intermediate product, such as a motherboard, or (b) an end product. The end product can be any product that includes integrated circuit chips, ranging from toys and other low-end applications to advanced computer products having a display, a keyboard or other input device, and a central processor.
[0055] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. | A method of fabricating a semiconductor interconnect structure by providing a semiconductor structure that includes two dielectric layers. The first dielectric layer has an embedded electrically conductive structure. A second dielectric layer is located above the first dielectric layer. The second dielectric layer and the first dielectric layer have a segment of a dielectric capping layer and a segment of a metal capping layer located between them. The segment of the dielectric capping layer is horizontally planar with the segment of the metal capping layer. The segment of metal capping layer covers and abuts at least a portion of a top surface of the first electrically conductive structure. The method includes forming an opening in the second dielectric layer and the metal capping layer that exposes at least a portion of the first electrically conductive structure and a portion of the dielectric capping layer. | 7 |
BACKGROUND OF THE INVENTION
This application relates to an apparatus and method for detecting a catastrophic fault in an optical fiber and more specifically to an apparatus for automatically detecting and indicating a location of an optical fiber fault.
It is well known to use fiber optical cables to transmit video, data or telecommunications signals over long distances between multiple locations. Fiber optic cables are typically provided in large bundles and have lengths of many miles. They are typically laid underground and connect one communications location to another location. These fibers may deteriorate the optical signal passing therethrough due to fiber bending, partial faults (cracks), accidental nicking, and/or other physical causes.
Because fibers are typically located underground and in large bundles, it is difficult to locate the position of the fiber's deterioration. It has also been a problem to continuously and to easily monitor the fiber bundle to determine if a deterioration condition develops when signals are being passed through the fiber.
SUMMARY OF THE INVENTION
An object of this invention is to provide an improved method and apparatus for detecting a fault in an optical fiber.
Another object of this invention is to provide a method and apparatus for monitoring an arbitrary number of fibers to determine the location of faults in the fibers.
A further object of this invention is to determine optical signal deterioration in the fiber due to fiber bending, partial faults (cracks) and/or other physical causes.
It is an additional object of this invention to determine a distance of a fault in a fiber by detecting a time duration through which the pulse propagates through the fiber from the first end and is reflected back to the first end.
It is also an object of this invention to indicate to the user the location of one or more faults in a fiber bundle.
These and other objects are provided with a method for detecting a defect in an optical fiber. The method includes the steps of transmitting into a first end of a normal fiber under test a pulse of optical energy and detecting a time duration through which the pulse propagates through the fiber from the first end and is reflected back. A variable corresponding to the first length of the fiber under test is stored in memory using the detected propagation time of the pulse of optical energy. These steps are then repeated at a later time with a second pulse of optical energy. The time from transmission to return of the second pulse propagating through the fiber under test is detected and a second variable corresponding to the second length is computed. This second variable would then be compared with the first variable. If a break in the fiber were present, the first variable computed would vary greater than a predetermined amount from the second variable. An error indication would then be provided along with a location of the break computed from the second variable. It may be preferable that in addition to detecting and comparing the reflected optical pulse, the intensity of the first and second reflected pulse are detected and compared. If the intensity varies by greater than a predetermined amount, an error indication is also provided.
In another embodiment of the invention an apparatus for detecting a defect in an optical fiber would include an optical transmitter transmitting into a first end of fiber under test a first pulse of optical energy and for transmitting into the first end a predetermined time period later a second pulse of optical energy. An optical receiver detects a propagation time duration of the first pulse and second pulse propagating through the fiber from the first end and being reflected back to the first end. A processor is included to store in a memory a first variable corresponding to the detected propagation time duration of the first pulse of optical energy. The processor stores in memory a second variable corresponding to a detected propagation time duration of the second pulse of optical energy. This second variable corresponds to the length of the fiber under test through which the second pulse of optical energy travels after hitting a fault. The processor compares the variable computed from the propagation time of the first pulse of optical energy with the variable computed from the propagation time of the second pulse of optical energy. The processor then indicates an error condition if the variable computed from the propagation time of the second pulse of optical energy varies greater than a predetermined amount from the variable computed from the propagation time of the first pulse of optical energy thereby indicating a break in the fiber. Upon indication of an error condition, the processor computes from the second variable a distance to the location of the fault.
DESCRIPTION OF THE FIGURES
FIG. 1 is a block diagram of a system for determining the location of a fault of a fiber in accordance with the invention;
FIG. 2 is a schematic diagram of the test apparatus for determining the location of a fault shown in FIG. 1;
FIG. 3 is timing diagram of the output of the test apparatus shown in FIG. 2;
FIG. 4 is a flow diagram of a learn mode for determining and storing for each normal fiber its length and pulse intensity for the processor shown in FIG. 2; and
FIG. 5 is a flow diagram of an interrogation mode for each fiber to determine a fault for the processor shown in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown a system 10 having test apparatus 14 coupled through signal lines 20 to headend 12 and coupled through fiber bundle 16 to a light reflector 18, which is preferably, a loop. Test apparatus 14 periodically transmits an initial optical signal through a first end 22 of each one of the normal fibers in fiber bundle 16. The optical signal propagates through each fiber in bundle 16 and is reflected back from the second end 24 of bundle 16 to first end 22. Test apparatus 14 during a learn mode determines the time the pulse travels through each fiber in bundle 16 and stores a variable corresponding to the length of each fiber 16 and the intensity of the reflected pulse as described herein in FIG. 4 and FIG. 5. Apparatus 14 compares during an interrogation mode the variable and intensity of the reflected pulse with an initially stored variable and initially stored intensity during a learn mode. If the compared variables and/or intensity vary by greater than a predetermined amount, apparatus 14 provides an alarm indication of a fault to headend 12 through signal lines 20 and provides an indication of the most recently recorded variable.
Referring to FIG. 2 there is shown the test apparatus 14 having a processor or logic unit 30 connected to display 32, optical device 34, power supply 36 and clock 38. One such logic unit is Model 6805 manufactured by Motorola of Phoenix, Ariz. Device 34 includes a diode laser 40 connected to laser modulator 42 and optical splitter 44. Laser 40 is connected through laser sensor 46 to unit 30 to indicate proper laser operation.
Optical device 34 also includes optical units 48A-48H coupled through lines 49 to the plurality of outputs of splitter 44. Optical units 48A-48H are individually enabled and disabled by receiver controller outputs 50 on unit 30. Each of units 48A-48H includes an optical coupler 52 and receiver (RX) 54. Diode 40 injects light through splitter 44 and coupler 52 to permit the optical signal to be passed to first end 22 (FIG. 1) of a respective fiber in bundle 16.
When each respective receiver 54 is enable, the reflected optical signal on the fiber in bundle 16 is passed through receiver 54 converted to a voltage signal and passed though lines 58 to analog to digital circuitry (A/D) 60 input of unit 30. A/D circuitry 60 converts the RF signal on line 58 to a digital signal corresponding to the intensity of the optical signal on the fiber in bundle 16.
Referring to FIG. 3, there is shown a timing diagram of the output of the test apparatus 14. In line 70, there is shown the output of clock 38 for the example case of a frequency of 2 MHz and a 50/50 duty cycle. Line 72 shows the output of laser 40, which periodically generates an optical pulse. In line 74, the output of logic unit 30 on line 50 is shown. Line 50 when active enables a respective receiver 54 in units 48A-48H. Lines 76-81 shows an example of reflected pulses received by unit 48A when receiver 54 in unit 48A is enabled as on line 74.
In lines 76-78 there is shown an example reflected pulse received by a receiver 54 units 48A-48H for normal fiber lengths of 20 and 30 Km, respectively. In this example receiver 54 was enabled as on line 74. During the interrogation mode, line 80 shows the reflected pulse reved by one of units 48A-H for the case that the 30 Km fiber has a break at 20 Km. As shown there, the reflected pulse occurs at an earlier time than the reflected pulse occurring in the normal fiber shown in line 78. During the interrogation mode, line 81 shows two reflected pulses received by one of units 48A-H for the casehat a 40 Km fiber has a partial break at 20 Km and full break at 30 Km.
Referring to FIG. 4 and FIG. 5 there are shown the steps executed in software within unit 30 during a Learn Mode (FIG. 4) and Interrogation Mode (FIG. 5). In the learn mode, unit 30 acquires the initial length of each normal fiber and intensity of the optical signal propagating through each of the fibers in bundle 16 as described with reference to FIG. 1. In the interrogation mode, each fiber in bundle 16 is checked against the length and intensity acquired during the learn mode. Logic unit 30 may be set to learn mode and automatically switch after a preset period of time to interrogation mode. Alternately logic unit may receive controls from a remote source or switches, front panel display, etc. to switch between learn and interrogation mode.
Referring to FIG. 4, there is shown the learn mode having steps 80-90. In step 80 the internal counters in unit 30 are reset. In step 82 the laser 40 is turned on and a pulse is sent through optical device 34 down the fibers in bundle 16. Next in step 84, the unit 48A-48H corresponding to the fiber that is to be tested is enabled. In step 85 the logic unit monitors its A/D circuit 60 for the received reflected pulse while simultaneously counting the clock clicks in step 86. In step 87, the intensity of the received pulse by A/D circuitry 60 is stored in a first register while in step 89 the number of clicks counted in step 86 is recorded in a second register. In optional step 88, a variable corresponding to the length of the fiber in bundle 16 is calculated. The formula to calculate the distance is (the number of clock ticks) times the speed of light constant (C) times (1/clock frequency) divided by (n), where n is the constant for the refractive index of the core of the individual fiber. The fiber length, L; is calculated according to the well known formula: L=(t/2)(c/n) where t is the total propagation time of the pulse from launch to reception in seconds and c is the speed of light in air, c=3*10 8 meters per second. This constant n can be downloaded from headend 12 to the processor 60 and set individually for different fiber types by the user. Next in step 90 after steps 88 and 87, steps 80-88 are repeated after a predetermined time period until the interrogation mode is enabled.
Referring to FIG. 5, there is shown the interrogation mode having steps 100-128. In step 100 the internal counters in unit 30 are reset. In step 102, laser 40 is turned on and a pulse is sent through optical device 34 to the fibers in bundle 16. Next in step 104, the one of units 48A-48H corresponding to the fiber that is to be tested is enabled. In step 106 the logic unit monitors its A/D circuit 60 for the intensity of the received pulse reflected in the fiber while simultaneously counting the clock ticks in step 108.
In step 110, the magnitude of the received pulse by A/D circuitry 60 is stored in a memory, and compared to the intensity recorded in step 87. In step 111 the processor determines if the intensity is within a "Y" predetermined amount. If it is, the processor executes step 123 where the interrogation mode process restarts a predetermined amount of time later. If it is not, the processor 30 executes step 117. In step 117, the processor sends an indication of the intensity stored in step 110 to the headend 12 or provides an indication on display 32 of apparatus 14 of the intensity to be reported. Either at the headend 12 or in apparatus an indication can be made whether this intensity is catastrophic or just a minor alarm.
Simultaneously to steps 106-117 in step 112, the number of clock clicks counted in step 108 is recorded in a second memory location. These clock clicks are recorded for one or two reflected pulses (see line 81 of FIG. 3). In step 114, a variable corresponding to the length of the fiber in bundle 16 is calculated or the variable recorded in the second memory location is compared against the variable recorded in step 89. In step 118 processor 30 determines if this comparison is within a predetermined amount. If so, the processor executes step 123 where the interrogation mode process restarts and steps 100-118 are repeated a predetermined time period later. If this variable is not within a predetermined amount ("X"), in step 121 an indication is stored indicating a failure. In step 121, this failure indication is checked to determine if this is the first failure or one of multiple consecutive failures. If it is a first failure, step 123 is executed. If the failure is reported a predetermined multiple and consecutive number times of then step 124 is executed.
In step 124 the distance is calculated using the number of clicks stored in the third register using the formula described in step 88. The distance is calculated for one reflected pulse as well as shown in line 80 of FIG. 3. In the case of a second reflected pulse as shown in line 81 of FIG. 3, the location of the break causing the second pulse can be determined using the similar method used to determine the first partial break. This calculated distance is then displayed on a display 32, fed to headend 12, or displayed on other indication device in step 126. In step 128 an alarm is indicated to headend 12 or to a display, or other indication device. After step 128, interrogation mode is repeated for each of the other fibers in bundle 16 to be tested.
It is noted that dark fibers may be tested, or alternated live fibers may be tested by using a pulse at a frequency other than the frequency of the signal being transmitted through the bundle.
While the principles of the invention have been made clear in the illustrated embodiments, there will be immediately obvious to those skilled in the art, many modifications and components used in the practice of the invention, which are particularly adapted for specific environments and operational requirements, can be used, without departing from those principles. The appended claims are therefore intended to cover and embrace any such modifications within the limits only of the true spirit and scope of the invention. | A method and apparatus for detecting a fault, such as a break or crack in a fiber optic cable. A test device transmits into a first end of fiber bundle under test a first pulse of optical energy. The time duration and/or intensity of the pulse propagating through the fiber after being reflected back through the fiber are determined and stored in memory. At a later point in time this step is repeated with a second pulse. If the propagation time and/or intensity of the second pulse varies by greater than a predetermined amount from that of the first pulse an alarm condition is indicated. From the propagation time of the second pulse a length is calculated and provided to the user. This length corresponds to the location of the fault. | 6 |
CROSS REFERENCE TO PRIOR CO-PENDING APPLICATION
[0001] This application claims the benefit of prior co-pending U.S. Provisional Patent Application Ser. No. 61/671,363 filed Aug. 29, 2013 entitled Show Lace Securing Device.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention is related to a device that will secure shoelaces and is especially related to an apparatus for use with athletic shoes, especially when worn by children.
[0004] 2. Description of the Prior Art
[0005] The securing of shoe laces has been and is a problem for small children as well as the athlete in competition. The present invention presents an easy method using a device that even a child can attach to his or her shoes and secure laces. The typical method of securing shoe laces can range from stuffing in the sides of one's shoes or stuffing into a pouch. These methods cannot be facilitated with ease and many times do not work or create a very unnatural look. This shoe lace securing device allows for an easy method to attach to shoes and allows a contoured fit which creates a natural fit and look for any shoe. The connected hook and loop or Velcro top piece or any product of the like secures the laces in place once placed between the bottom and top piece of the present invention.
SUMMARY OF THE INVENTION
[0006] The shoe lace securing device will be made of a Velcro material or anything of the like that will secure laces together once located between the top and bottom flaps of the present invention. The present invention will have a flexible curved piece sewn, attached or connected to the bottom piece that will slide with ease underneath of laces of shoes. This will not only secure the shoe lace securing device in place but will contour to the front of shoe to give a natural look that will distinguish itself from any competitive product. This will also allow no points of contact to stick out allowing one to kick a ball with ease so that it will not deviate from its intended direction. Two tabs will be sewn on each end to allow easy opening and closing of the show lace securing device of the present invention.
[0007] As used here the terms deform or deformable or the like shall mean that the shape of a deformable component can be changed, but that a deformable component need not have any memory or would not naturally return to its original shape. The term flexible shall mean that a component is able to bend without breaking and can refer either to a component that has an inherent memory, such as a spring, or which has not inherent member such as a flexible cloth. The term resilient shall be understood to mean a component that is both deformable and flexible, but that does have a memory so that it can or will return to its original shape unless some external force prevents return to the original shape.
[0008] According to one aspect of this invention, a device according to this invention can be used to secure end portions of a shoe lace extending beyond eyelets on a shoe. This device has an upper section and a lower section. The upper section is flexible and the lower section is deformable to a curved configuration to fit over a portion of the shoe extending over a wearer's foot instep. The upper section will extend from one end of the curved lower section. The upper section is foldable over portions of the shoe laces extending over the curved lower section and can be attached to and detached from the lower section in a curved configuration at an opposite end from the one end from which the upper section extends to trap end portions of the shoe lace extending beyond eyelets on the shoe.
[0009] The device according to another aspect of this invention is also used to secure end portions of a shoe lace extending beyond eyelets on a shoe. The device has an elongated strip of material comprising an upper section and a lower section wherein the lower section is dimensioned to fit between a portion of shoe laces that are laced between eyelets on a shoe. A relatively narrower central section joins a relatively wider section adjacent a leading end of the lower section. The relatively wider section includes an upwardly facing fastener. The upper section is joined to the relatively narrower central section of the lower portion and the upper section is wider than the relatively narrower central section. The upper section can be folded over the lower section and laces extending between eyelets. The upper section includes a downwardly facing fastener attachable to the upwardly facing fastener to trap end portions of shoe laces extending beyond the eyelets.
[0010] In a method according to this invention end portions of shoelaces on top of a shoe are held in place or secured so that the shoelaces will not be exposed and will not become undone or protrude so as to cause a wearer to trip.
[0011] This method includes the steps of inserting a lower section of a securing device beneath and through shoelaces extending and laced between eyelets on the shoe so that the lower section extends beyond both sides of the tongue of the shoe. The lower section is deformable to conform to the wearer's instep. The upper section is folded over the end portions of the shoelaces after the shoelaces have been tied by the wearer and fastening a leading end of the upper section to a leading end of the lower portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a shoe with the lace securing device extending over the loops of the laces.
[0013] FIG. 2 shows the top of the shoe and the lace securing device in FIG. 1 .
[0014] FIG. 3 shows one end of the lace securing device extending between the laces with the top portion of the lace securing device in the disengaged position.
[0015] FIG. 4A shows the initial insertion of the forward end of the lower portion of the lace securing device initially inserted beneath the laces, prior to complete insertion of the lower portion of the lace securing device.
[0016] FIG. 4B shows the manner in which the lower portion of the lace securing device extends beneath the laces extending through eyelets in the shoe.
[0017] FIG. 5 shows the lace securing device with the lower portion being curved to fit the top of the foot.
[0018] FIG. 6 shows the two layer construction of the lace securing device with a flexible curved insert which will be positioned in a pocket.
[0019] FIG. 7 shows the pocket of FIG. 6 with the flexible curved insert can residein the pocket in a flattened position.
[0020] FIG. 8 shows the two layers being folded over to secure the flexible curved insert in the pocket that will be closed upon final assembly.
[0021] FIG. 9 shows an alternate embodiment of the lace securing device in which the lower portion that will be fitted beneath the laces in a shoe is narrower for better fit.
[0022] FIG. 10 shows the alternate embodiment positioned on a shoe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] FIG. 1 shows the shoe lace securing device 10 made of a hook and loop or Velcro material (Or material of the like) that secures laces 4 in place once the laces 4 placed in between the top 12 and bottom 14 portions or flaps of the device 10 , as seen in FIG. 2 . The shoe lace securing device 10 is laced between laces 4 that are already on the shoe 2 , although it may be necessary to loosen the laces 4 in order to apply the device 10 .
[0024] FIG. 2 is a side view of lace securing device showing the leading edge of the top portion 14 which is secured to the bottom portion 12 by the hook and loop fasters forming the mating surfaces therebetween. FIG. 2 also shows the natural look of the shoe 2 and the securing device 10 as it secures laces 4 . The securing device 10 opens with tab 16 ( FIG. 3 ) on the leading end. Laces 4 are placed overtop of bottom portion 14 and top flap 12 secures laces once folded over laces and secured with Velcro or any product of the like. The top portion or flap 12 folds overtop the bottom flap 14 to secure laces 4 therebetween.
[0025] FIG. 3 shows how the laces overlay onto the bottom piece or flap 14 of the lace securing device, and the tabs 16 , 22 on each end to allow for easy opening and closing.
[0026] FIG. 4A shows how the bottom flap 14 is initially inserted or threaded in place between laces in the shoe 2 . The bottom contoured portion 14 is curved with the bottom tab 22 located on the leading edge of this contoured portion so that it can be used to pull the curved bottom flap beneath the shoe laces 4 FIG. 4B shows the bottom flap 14 after it has been completely inserted between the laces 4 on the shoe 2 . The top flap 12 will then be folded over to secure laces 4 in place.
[0027] FIGS. 4A and 4B : The below shows the ease in which the shoe lace securing device is threaded in place underneath ones shoe laces. The rounded or pointed ends allow an easy method to secure the device in place; even a child would be able to secure in place. The top portion will then be placed over top of the laces to secure in place.
[0028] FIG. 5 shows how a deformable piece placed inside or on the top or bottom of the present invention can impart a curved or round contour to the bottom portion 14 of the securing device 10 so that it will fit on the top curved surface of any shoe 2 . This allows one to create a natural look as if the securing device 10 was part of the shoe 2 itself. It will also allow no points to be sticking up and it is important while playing sports to allow a natural point for foot to ball contact in sports such as soccer or football. The bottom portion of shoe lace securing device 10 has a deformable piece or material such as metal, plastic or a product of the like, which may also be either flexible or resilient, embedded inside the inner and outer layers that that is sufficiently flexible to allow the lace securing device 10 to contour naturally around a shoe 2 . This creates a natural look that would be attractive for any type of kids' shoes, man's work or hunting boots, work shoes, or athletic shoes. The top flap 12 when fitted over the curved bottom flap 14 will also exhibit this same curved contour.
[0029] FIG. 6 shows a deformable curved or curvable piece 40 exploded from a pocket 30 formed by two layers 32 and 34 forming the lace locking device 10 . FIGS. 7 and 8 show how the curved or curvable piece 40 can be fitted in pocket 30 formed by the two layers 32 and 34 . FIG. 7 shows how the curved piece 40 has sufficient flexibility so that it can be flattened. The curved piece 40 can possess sufficient resiliency so that it will tend to return to a curved configuration unless flattened by the exertion of a force on the ends of the curved piece 40 or when prevented from returning to its original shape by the wearer's foot when fitted on top of a shoe as shown in FIG. 1-4B .
[0030] The deformable piece 40 can be deformable only, deformable and flexible or resilient, depending upon the embodiment chosen. In one embodiment, the deformable piece can be fabricated from a material such as a soft, cast metallic member that does not have member and can be shaped into a relatively stable curved configuration that will conform to a wearer's instep and to the top of a shoe. After the lower section is inserted beneath the shoelaces, such a deformable material can be pressed into its curved configuration. Such a soft material can be deformed to a flatter configuration to remove the lower section from beneath the shoelaces.
[0031] Another embodiment of the deformable piece 40 can be a spring member having a curved configuration generally in the shape of a C and can be resilient so that it will have sufficient memory to return to the curved C-shaped configuration unless acted on by an external force or forces. Such a spring member can be flatted to allow it to be inserted beneath the shoelaces, but it will returned to or toward its C-shaped configuration unless prevented from fully returning by the presence of the top of the shoe or the wearer's instep. This resilient deformable member will thus tend to conform to the shape of the top of the shoe or the wearer's instep.
[0032] A bistable spring can also be used to form the deformable piece 40 . A bistable spring is a spring that is flexible and will tend to return to either of two different configurations. If a generally rectangular strip of spring metal is curved relative to an axis parallel to its longitudinal dimension, the bistable spring will tend to reside in a first stable state in which the bistable spring is generally flat or elongate. However, when a force perpendicular to the longitudinal axis is applied so such a bistable spring the spring will return to a curved or coiled state. An opposed force applied to the bistable spring in its curved stable state will cause the bistable spring to return to its other generally flat stable state. Such a bistable spring can be employed as the deformable piece 40 so that the bistable spring can be inserted through the shoelaces in its flat state and can then be released from that state to a curved state in which the deformable piece 40 would generally conform to the top of the shoe or the wearer's instep. A second bistable spring could also be employed to form the top section of the securing device which can be folded over the shoe laces in an overlapping configuration relative to the lower section and the lower bistable deformable piece 40 . When a bistable spring is used to form the deformable piece 40 , and/or the upper section, a plastic coating, such as neoprene, can be formed over the bistable spring.
[0033] In another embodiment a bistable spring securable to the shoe and can be positioned in a curved configuration over the top of the shoelaces. The bistable spring of this configuration will conform to the top of the shoe and the wearer's instep when placed the top of the shoelaces. One end of the bistable spring can be attached to loop or a chain or other connecting means, which can be attached to the shoelaces or through an eyelet so that the bistable spring will not become inadvertently detached when the shoe if not being worn.
[0034] FIGS. 9 and 10 show an alternate embodiment of a lace securing device 60 in which a portion 64 of the lower piece has a smaller width that the two portions 62 and 66 on either end. This narrower section 64 will fit beneath the laces 4 so that the laces can be sufficiently tightened so that the shoe 2 will have a normal feel and appearance when the laces 4 capture the section 64 therein, as shown in FIG. 10 . A pull tab 68 extends from the leading end of wider portion 62 to assist in pulling the lower section beneath the shoelaces extending between the eyelets on the shoe.
[0035] Other usages include a shoe lace securing device including a tracking monitoring device that can be embedded in present invention to track amount of time one has exercised to monitor amount of playing time and keep statistical numbers of playing time in competitive games. An app could be made for any mobile device to analyze the information.
[0036] The top of the lace securing device can have removable advertising area (tab) that one can advertise or promote ones team, logo, or be a location for ones identification.
[0037] The top portion of lace securing device can also have advertising sewn on it to display favorite teams, logos, player's names, kids' names or anything to promote ones interest.
[0038] In addition to providing a means for securing shoe laces, especially for children engaged in sports, the securing device of this invention can also incorporate a transmitter that can serve as a monitoring device in conjunction with corresponding software or an app, which would allow a parent to track a child's current location. | The present invention is a device positionable over the top of a shoe and over a wearer's instep to allows shoe laces of ones shoes to be secured in place. This device includes a lower piece that feeds under ones laces and contours to the shoe and instep to a tight fit to allow the appearance of being a natural part of one's shoes. A top piece or flap of this device that is connected to the lower piece folds overtop of the laces once placed in and is the secured to the lower piece to hold the laces in place. | 0 |
BACKGROUND OF THE DISCLOSURE
The present invention relates to valve control systems for internal combustion engines of the type in which the movement of an engine poppet valve is controlled in response to rotation of a cam shaft, and more particularly, to such a valve control system in which the cam shaft has a cam profile including both a high lift portion and a low lift portion.
Even more specifically, the present invention relates to such a valve control system including a dual lift rocker arm assembly of the type having both a high lift cam follower and a low lift cam follower (for engagement with the high lift portion and the low lift portion, respectively, of the cam profile). Although the terms “high lift” and “low lift” can have various meanings when used in regard to valve control systems for engine poppet valves, it should be understood that, within the scope of the present invention, all that is required is that one cam profile provide a relatively higher lift of the engine poppet valve while the other cam profile provides a relatively lower lift of the engine poppet valve. Within the scope of the invention, the “low lift” could actually comprise zero lift, or could comprise some finite lift amount which is greater than zero lift, but somewhat (or substantially) less than the “high lift”.
In a typical dual lift rocker arm assembly, of the type which is now well known in the art, there is provided an outer rocker arm and an inner rocker arm, with those two rocker arms typically being pivotally connected relative to each other toward one axial end thereof. In addition, the typical, prior art dual lift rocker arm assembly includes some sort of latch mechanism, operable to latch the inner rocker arm to the outer rocker arm, such that the two rocker arms move in unison about a fulcrum location, such as the ball plunger of a hydraulic lash adjuster. This “latched” condition, as described above, would typically, but not necessarily, correspond to the high lift mode of operation of the valve control system. When the latch mechanism is in the “unlatched” condition, the inner and outer rocker arm are free to pivot relative to each other, and this unlatched condition would typically, but not necessarily, correspond to the low lift mode of operation of the valve control system.
Dual lift, latchable rocker arm assemblies are illustrated and described in U.S. Pat. Nos. 5,524,580; 5,584,267; and 5,697,333, all of which are assigned to the assignee of the present invention, and incorporated herein by reference.
In the dual lift rocker arm assemblies of the above-incorporated patents, there is provided some sort of electromagnetic actuator for controlling the operation of the latching mechanism. Although such electromagnetic actuation of the latching mechanism has been found to operate in a generally satisfactory manner, the resulting need for a separate electromagnetic actuator for each rocker arm assembly would add substantially to the cost of the overall valve control system, and in many applications, would require much more space for “packaging” than is available in the typical engine cylinder head.
Those skilled in the art have attempted to provide a means of actuation for the latching mechanism of a dual lift rocker arm assembly, which would overcome the prior art problems discussed above, by utilizing hydraulic pressure. Specifically, those skilled in the art have attempted to utilize, to control the latching mechanism, a variable hydraulic pressure within the plunger of the hydraulic lash adjuster, which serves as the fulcrum location for the rocker arm assembly. Such an actuation arrangement is illustrated and described in U.S. Pat. Nos. 5,544,626 and 6,668,779, both of which are incorporated herein by reference.
Although the rocker arm assemblies of the above-incorporated patents, in the immediately preceding paragraph, do provide at least the potential for substantially improved actuation of the latching mechanism, the need to communicate the low pressure (control) fluid from the lash adjuster to the latching mechanism has somewhat complicated the design of the rocker arm assembly. This is especially true when it is recognized that there are various other design criteria for rocker arm assemblies which must be observed, in order to achieve the best possible overall performance of the valve control system. For example, in order to improve the dynamic behavior of the valve control system, it is desirable to reduce the inertia of the rocker arm assembly. One way of reducing the inertia is to locate as much of the mass of the rocker arm assembly as close as possible to the fulcrum location. Therefore, it is recognized that it is desirable to have the pivot axis, between the inner and outer rocker arms, disposed adjacent the fulcrum location, such that the torsion spring, which biases the rocker arms relative to each other, may also be near the fulcrum location.
Unfortunately, in the dual rocker arm assembly of the above-incorporated U.S. Pat. No. 6,668,779, in order to utilize a control fluid from the hydraulic lash adjuster to control the latching mechanism, it was necessary to add a piston member (the only function of which was to move in response to changes in control pressure), with the movement of the piston member being transmitted from the piston member to the latching mechanism at the opposite end of the rocker arm assembly by means of a separate slider element, having no function other than to move the latching mechanism in response to movement of the piston member. The added cost and complexity of the arrangement in the rocker arm assembly of the '779 patent, as well as the added mass and inertia of the assembly, make the overall assembly less than desirable commercially.
BRIEF SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved valve control system, for controlling engine poppet valves, wherein the system is of the type including a dual lift rocker arm assembly which is able to overcome the above-discussed disadvantages of the prior art.
It is a more specific object of the present invention to provide such an improved dual lift rocker arm assembly in which the latching mechanism is controlled by pressurized fluid from the hydraulic lash adjuster, but which does not require substantial added structure, cost, and weight in order to transmit changes in fluid pressure into movement of the latch mechanism.
The above and other objects of the invention are accomplished by the provision of a valve control system for an internal combustion engine of the type including a cylinder head, and a poppet valve moveable relative to the cylinder head between open and closed positions, and a cam shaft having a first cam profile and a second cam profile formed thereon. The valve control system comprises a rocker arm assembly including a first rocker arm having a first cam follower in engagement with the first cam profile, and a second rocker arm having a second cam follower in engagement with the second cam profile. The valve control system further comprises the cylinder head including a fulcrum location operable to provide a source of pressurized fluid. The first rocker arm defines, toward a first axial end thereof, a fulcrum surface adapted for pivotal engagement with the fulcrum location. The first rocker arm further defines, adjacent the fulcrum surface, a pivot location whereby the second rocker arm pivots relative to the first rocker arm about the pivot location. The first rocker arm includes, toward a second axial end thereof, a latch assembly including a latch member moveable between latched and unlatched conditions, relative to a latch surface defined by an adjacent portion of the second rocker arm. A spring biases the latch member toward one of the latched and unlatched conditions, and the latch assembly defines a pressure chamber operable to bias the latch member toward the other of the latched and unlatched conditions.
The improved valve control system is characterized by the first rocker arm defining a fluid passage having a first end in open fluid communication with the fulcrum surface, the first end of the fluid passage being operable to receive pressurized fluid from the source. The fluid passage has a second end in open fluid communication with the pressure chamber of the latch assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a dual lift rocker arm assembly of the type which may utilize the present invention.
FIG. 2 is a perspective view of the rocker arm assembly of FIG. 1 , but taken from the opposite end, and looking upward.
FIG. 3 is a view generally similar to that of FIG. 2 , but showing only the inner rocker arm, and taken at a slightly different angle than FIG. 2 .
FIG. 4 is a side plan view, looking toward the side which is on the bottom in FIG. 3 , showing primarily only the inner rocker arm.
FIG. 5 is an axial cross-section, taken generally on line 5 — 5 of FIG. 4 , of the inner rocker arm, including the fluid passage which comprises one important aspect of the invention.
FIG. 6 is a greatly enlarged, fragmentary, axial cross-section, on a “vertical” plane, showing in greater detail the latch mechanism which comprises one aspect of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, which are not intended to limit the invention, FIG. 1 illustrates a dual lift rocker arm assembly, generally designated 11 , of the general type illustrated and described in U.S. Pat. No. 5,655,488, assigned to the assignee of the present invention and incorporated herein by reference. One reason for referring to the incorporated patent is that it shows the cam shaft, including the high lift and low lift cam profiles, as well as a portion of the cylinder head, and also shows the engine poppet valve, none of which are illustrated herein, for the sake of simplicity, and because such elements are well known to those skilled in the art, and do not require detailed description.
Referring still to FIG. 1 , the dual lift rocker arm assembly 11 of the present invention comprises an inner rocker arm 13 (also referred to hereinafter in the appended claims as a “first” rocker arm). The inner rocker arm 13 includes a roller follower 15 which, in the subject embodiment, would comprise the “low lift” cam follower, and would engage the low lift cam profile on the cam shaft. As may best be seen in FIG. 6 , the roller follower 15 rotates about an axis designated “a”.
Referring still primarily to FIG. 1 , the dual lift rocker arm assembly 11 further comprises an outer rocker arm 17 (also referred to hereinafter in the appended claims as a “second” rocker arm). The outer rocker arm 17 includes a pair of sidewalls 19 and 21 , disposed on laterally opposite sides of the inner rocker arm 13 . The sidewalls 19 and 21 include a pair of pad portions 23 and 25 , respectively, and the pad portions 23 and 25 would comprise the “high lift” cam follower, and would engage the high lift cam profile on the cam shaft. As is well known in the art, the high lift cam profile, for use with the dual lift rocker arm assembly 11 , would comprise a pair of cam profiles, disposed on either side, axially, of the low lift cam profile.
As may best be seen in FIGS. 1 and 2 , the inner and outer rocker arms 13 and 17 are connected to each other, for relative pivotal movement, by means of a transversely-oriented shaft 27 . The shaft 27 (also shown in FIGS. 4 and 5 ), has its end portions received within openings in the sidewalls 19 and 21 of the outer rocker arm 17 and has its middle portion disposed within a circular opening 29 (see FIGS. 3 and 4 ) defined by the inner rocker arm 13 . In a surrounding relationship to portions of the shaft 27 , on either lateral side of the inner rocker arm 13 , are several turns of a torsion spring 31 , shown only in FIGS. 1 and 2 . As is well known to those skilled in the art, the purpose of the torsion spring 31 is to bias the inner rocker arm 13 counterclockwise in FIG. 1 , relative to the outer rocker arm 17 , about the shaft 27 .
Referring now primarily to FIG. 3 , the inner rocker arm 13 preferably comprises a single, unitary item which may be produced as a casting and subsequently machined, or may be produced as a powdered metal part. It should be understood by those skilled in the art that the present invention is not limited to the particular configuration of, or the process for manufacture of, the inner rocker arm 13 , and the configuration shown herein is by means of example only, except as will be noted hereinafter and in the appended claims.
The inner rocker arm 13 defines a generally hemispherical fulcrum surface 33 which, as is well known to those skilled in the art, is adapted for engagement with a member which serves as a “fulcrum location”. By way of example only, the fulcrum location can comprise a ball plunger portion (identified as “P” in FIG. 4 ) of a hydraulic lash adjuster, such that both the ball plunger portion and, where appropriate, the hydraulic lash adjuster itself (“fulcrum location”), may hereinafter bear the reference designation “P”. As is also now well known to those skilled in the art, the hydraulic lash adjuster is typically received within a cylindrical bore defined by the engine cylinder head (not shown herein for ease of illustration).
Referring now primarily to FIGS. 1 , 3 and 5 , the inner rocker arm 13 defines, at its end axially opposite the circular opening 29 , a latch bore 35 , and disposed within the latch bore 35 is a latch assembly, generally designated 37 (shown only in FIG. 6 ), and to be described in greater detail subsequently. It may be seen in FIG. 6 that the inner rocker arm 13 defines a valve pad 38 (also shown in FIG. 2 ) for engagement with the valve stem tip portion of the poppet valve. Disposed intermediate the opening 29 and the latch bore 35 , the inner rocker arm 13 defines a central open chamber 39 (see also FIG. 3 ), the roller follower 15 being disposed in the open chamber 39 , rotatably mounted upon a roller shaft 41 (see FIG. 4 ). Although the present invention is not limited to use with any particular configuration of rocker arm assembly, except where specifically otherwise noted in the appended claims, the invention is especially useful in the dual lift rocker arm assembly 11 , of the type shown herein, in which the fulcrum surface 33 is disposed toward one axial end of the inner rocker arm 13 , and the latch bore 35 is disposed toward the opposite axial end, with the roller follower 15 disposed axially therebetween, for reasons which will become apparent subsequently.
Referring now primarily to FIG. 6 , the latch assembly 37 includes a spring cage 43 , seated against a shoulder formed by the latch bore 35 , and with the spring cage 43 being trapped in the position shown by a latch bore plug 45 , which is preferably pressed into the latch bore 35 . Disposed within the latch bore 35 , and axially movable therein, is a latch member 47 , biased toward a retracted (“unlatched”) position by a generally conical latch spring 49 , which has its left end (in FIG. 6 ) seated against an adjacent surface of the spring cage 43 . The latch assembly 37 defines a pressure chamber 51 , which comprises the region within the latch bore 35 , disposed axially between the latch bore plug 45 and the latch member 47 . When pressurized fluid is communicated into the pressure chamber 51 , the latch member 47 is biased to the left in FIG. 6 , to the extended (“latched”) position, generally parallel to an axis A defined by the inner rocker arm 13 . In the latched position of the latch member 47 , a flat, planar upper surface of the latch member 47 engages an adjacent lower surface 52 defined by an endwall 53 of the outer rocker arm 17 (see also FIG. 2 ).
Referring again primarily to FIGS. 3 , 4 and 5 , the inner rocker arm 13 defines an axially-extending (i.e., generally parallel to the axis A of the rocker arm 13 ) bore 55 , an open end of which is visible in FIG. 3 . As is best shown in FIG. 5 , although somewhat schematically, an angled bore 57 is formed within, and defined wholly by, the inner rocker arm 13 . By way of example only, the angled bore 57 may be formed by drilling, with the drill bit entering the inner rocker arm 13 from the circular opening 29 , then proceeding until the bore 57 intersects the fulcrum surface 33 (or a bore extending somewhat vertically “upward” therefrom). The drill bit then continues until the resulting angled bore 57 is in open communication with the axially-extending bore 55 . Preferably, but not necessarily, when the shaft 27 is inserted into the opening 29 , the fit between the shaft 27 and the opening 29 is close enough (and perhaps even comprises a press-fit), such that the shaft 27 effectively “seals” the angled bore 57 from excessive fluid leakage. Those skilled in the art will understand that, for purposes of the present invention, absolute leakage-free sealing is not essential, but instead, all that is required is that the end of the angled bore 57 be sufficiently sealed to be able to build enough fluid pressure within the bore 55 and 57 to achieve the biasing of the latch member 47 .
Referring now primarily to FIGS. 4 , 5 and 6 , another angled bore 59 is formed within, and defined wholly by, the inner rocker arm 13 . In the same manner as for the angled bore 57 , the angled bore 59 may be formed by drilling, with the drill bit entering the inner rocker arm 13 from above, and then through, the latch bore 35 , then proceeding until the angled bore 59 is in open fluid communication with the axially-extending bore 55 . Preferably, but not necessarily, the latch member 47 effectively “seals” the angled bore 59 , although, as in the case of the angled bore 57 , it is sufficient if the angled bore 59 is sealed enough such that pressure is able to build up within the pressure chamber 51 , sufficient to bias the latch member 47 to the latched position shown in FIG. 6 . It should be noted that, in FIG. 5 , the reference numeral “ 59 ” appears twice, including a schematic (centerline) representation of the angled bore, and a physical representation where the angled bore 59 intersects the axially-extending bore 55 . However, the angled bore 59 is also shown in FIG. 6 , wherein just an upper terminal end of the bore 59 , “above” the latch bore 35 , is visible. It should be understood, when viewing FIG. 6 , that the plane of the angled bore 59 does not coincide with the plane of FIG. 6 , but instead is at an angle relative thereto.
Thus, by means of the series of bores just described, pressurized fluid is enabled to flow from above the ball plunger portion P “down” (in FIG. 4 ) through the angled bore 57 , into the axially-extending bore 55 , then flow to the left in FIG. 5 , then flow “upward” (in FIG. 4 ) through the angled bore 59 . The pressurized fluid in the bore 59 then flows into the pressure chamber 51 , because the angled bore 59 intersects the latch bore 35 “behind” the plane of the drawing in FIG. 6 . It should be noted that, in the appended claims, there will be reference made to a “fluid passage” (the axially-extending bore 55 ), having a “first end” (angled bore 57 ) in communication with the source of pressurized fluid, and a “second end” (the angled bore 59 ) in communication with the pressure chamber 51 of the latch mechanism.
Although not shown herein, it would be preferred to insert some sort of sealing ball or plug into the left end (in FIG. 5 ) of the axially-extending bore 55 . There may also be a need to insert a sealing ball or plug into the upper end of the angled bore 59 . In accordance with one worthwhile aspect of the preferred embodiment of the invention, in spite of needing three separate bores (passages, etc.) to communicate pressurized fluid from the “source” of the pressurized fluid (ball plunger portion P) to the pressure chamber 51 of the latch mechanism 37 , at only two locations (left end of bore 55 and upper end of bore 59 ) are any extra sealing members perhaps required. This particular feature is significant in connection with reducing the overall manufacturing cost, and time of assembly of the invention.
It should be understood by those skilled in the art that, although fluid communication from the HLA to the latch member is shown and described herein as being accomplished by means of the fluid bores 57 , 55 , and 59 , the use of such an “integral” passage is not a limitation of the present invention. By way of example only, the required fluid communication could, within the scope of the invention, be accomplished by means of a separate tubular member, brazed or otherwise attached to the inner rocker arm 13 at two spaced apart locations, but providing fluid communication from the ball plunger portion P to the pressure chamber 51 . All that is essential to the present invention is that no extra (not otherwise needed) mechanical structure be required to “transmit” the effect of fluid pressure from the source (at one end of the inner rocker arm 13 ) to the latch assembly 37 (at the axially opposite end).
Although the bore 55 , 57 and 59 have been described above in connection with a forming process involving drilling of the bores, it should be understood that the invention is not so limited. For example, if the inner rocker arm 13 is formed as a powder metal part, the bores 55 , 57 and 59 could be formed by inserted members which would be withdrawn from the PM die after the formation of the inner rocker arm, to allow the rocker arm to be removed from the die. Thus, those skilled in the art will understand that the particular method chosen to form the bore 55 , 57 and 59 is not a significant feature of the invention, as long as pressurized fluid may be communicated from the fulcrum surface 33 to the pressure chamber 51 .
The invention has been described in great detail in the foregoing specification, and it is believed that various alterations and modifications of the invention will become apparent to those skilled in the art from a reading and understanding of the specification. It is intended that all such alterations and modifications are included in the invention, insofar as they come within the scope of the appended claims. | A valve control system including a camshaft having first and second cam profiles, the valve control system comprising a rocker arm assembly ( 11 ) including a first rocker arm ( 13 ) having a first cam follower ( 15 ) in engagement with the first cam profile, and a second rocker arm ( 17 ) having a second cam follower ( 23,25 ) in engagement with the second cam profile. The engine includes a fulcrum location (P) operable to provide a source of pressurized fluid, and the first rocker arm includes a latch member ( 47 ) moveable between latched (FIG. 6 ) and unlatched conditions. The latch member is biased toward the latched condition by a fluid pressure in a chamber ( 51 ), and the first rocker arm defines a fluid passage ( 55 ) having a first end ( 57 ) in open fluid communication with the pressure source, and a second end ( 59 ) in open fluid communication with the pressure chamber ( 51 ). | 5 |
BACKGROUND OF THE INVENTION
This invention relates in general to a sewing machine for producing a stitch contour in a workpiece according to a predetermined program. A movably arranged workpiece receiving device is controlled with respect to the needle by means of a linkage cooperating with a control cam. In particular, a new device mounts adjustably the control cam to affect portions of the stitch contour with respect to their relative position.
Generally it is known to adjustably mount the control cam of a sewing machine of the aforementioned type, in order to synchronize the feed movement of the workpiece receiving device in relation to the stitch forming elements.
In U.S. Pat. No. 2,495,069 there is illustrated such a sewing machine, in which the control cam is mounted by a device to allow an angular adjustment. From U.S. Pat. No. 2,410,679 there is known a hub connection provided with a device to allow an angular fine adjustment, in which a hub may be adjusted in relation to a shaft by set screws.
Moreover, in U.S. Pat. No. 4,073,252 there is illustrated a sewing machine of the kind described above, for stitching a pocket to a workpiece. In contrast to the aforesaid sewing machines there are produced here stitch contours of a relative large size and which are fixed in their geometric configuration. Due to the limitation of the size of the control cam, such large stitch contours are essentially achieved by applying a linkage installed with a large ratio for converting the drive movements of the cam to the required movements of the workpiece holder, according to the stitch configuration in relation to the needle. As further described, the clamping plate moves the workpiece including the pocket on a stationary base plate by which forces of friction are induced into the control system depending on the material of the workpiece. Furthermore, a shifting at the workpiece and within the layers is caused by the continuous workpiece feeding movements regardless of the needle penetrating the material. Due to these circumstances, the geometry of the stitch configuration is negatively affected. Considering additionally the facts, that the linkage shows a different mechanical stiffness depending on the direction of the feed, it becomes quite obvious, that such influences cannot be taken in account when determining the cam data.
In the process of attaching a pocket to a workpiece by means of a double U-shaped stitch pattern, the aforesaid described problem of geometric deformation causes unequal distances between the individual stitch portions, and injures the appearance of the work. This is most important, if the stitch pattern is emphasized by using a specially colored thread for decorative purposes.
In practice, it has been shown that an exactly computed control cam of such type of sewing machine, does not necessarily furnish the desired quality with respect to the geometric configuration of a sewn pattern at the first attempt. Since there are no possibilities of adjustment, a corrected control cam must be consequently produced in order to compensate the above-described influences. Such an experimental method for producing the control cam is time-consuming and expensive. It is furthermore connected with significant problems when providing a sewing machine already in the field, with another control cam in order to produce a different stitch pattern, as the described influences depending on the material to be processed and the geometry of the stitch pattern, may be judged only after the sewing process.
Accordingly, it is the main object of the present invention to install in a cam controlled linkage of a sewing machine an adjustment device which makes it possible to adjust portions of the stitch pattern in their geometric arrangement.
It is a further object of the present invention to eliminate the experimental procedure of producing a control cam in order to reduce time and costs.
A still further object of the present invention is to create an adjustment device which makes it possible to supply control cams for producing different stitch patterns with sewing machines that are already in the field.
Another object of the present invention is to make the adjustment device of the aforesaid character a part of the sewing machine, so as not to increase the costs of the pattern-depending control cam.
Still another object of the present invention is to provide a device of the aforegoing character which is simple in construction and reliable in operation.
SUMMARY OF THE INVENTION
The objects of the present invention are achieved by providing a control cam adjustment device allowing a lateral displacement of the control cam with respect to the axis about which the cam rotates. Due to this principle of adjustment, the effective radii of sections of the control cam are displaced relative to each other.
The provision of two eccentrical rings arranged on a hub and interposed between the hub and the cam allows adjustment of both, lateral displacement as well as the direction of the lateral displacement of the cam without the necessity to either rotate the cam or to rotate the shaft while carrying out the adjustment procedure. By dimensioning both eccentrical rings with an equal amount of eccentricity, an adjustment is achieved within the limits of zero and twice the amount of eccentricity.
The arrangement of conical portions at the interposed eccentric rings and the bore of the control cam allows elimination of any play within the control cam adjustment device, and furthermore assures an undesired coming off adjustment of the eccentric rings.
The installation of adjustment marks at the elements of the adjustment device and the cam assures easy refinding of a once experienced adjustment, which is important when different styles of patterns are produced alternatively.
The arrangement of a pin cooperating with the recess in the plane surface of the control cam allows liberating the adjustment device from any torque-transmitting function and also forms a positive drive connection between the shaft and the control cam.
Other objects, advantages and features of the present invention will appear from the detailed description of the preferred embodiment, which will now be explained in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a sewing machine including a workpiece receiving device which is guided by a control cam via a linkage;
FIG. 2 is a partial front plan view of the sewing machine in the direction of the arrow II in FIG. 1;
FIG. 3 shows the novel control cam adjustment device in a sectional view taken along line III--III of FIG. 1;
FIG. 4 is a top plan view of the control cam adjustment device taken along line IV--IV of FIG. 3;
FIG. 5 is a top plan view of the partially illustrated control cam adjustment device in the direction of the arrow V in FIG. 3;
FIG. 6 is a top plan view of a control cam illustrated with an angular graduation, with, however, the mounting bore omitted;
FIG. 7 shows a workpiece with a patch pocket attached by a double seam;
FIG. 8 shows a workpiece with a patch pocket attached by a single seam; and
FIG. 9 is a symbolic illustration of the control cam adjustment device having two eccentrics.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a sewing machine having a sewing head 1, the base plate 2 of which is connected to a plate 3 mounted by posts 4 to a frame 5. To the plate 3 there is displaceably supported a workpiece receiving device 7 by a linkage 6 for moving a workpiece 8 along a needle 9 of the sewing head 1 according to a predetermined seam contour. The workpiece receiving device 7 substantially consists of a pressure plate 10 lowerable upon the base plate 2 by means of actuating elements (not shown). The pressure plate 10 is provided with a slot 11 which corresponds to the U-shaped seam contour and which enables the needle 9 to penetrate the workpiece 8. The linkage 6 is journaled at a pivot 12 located at the frame 5, which also receives a gear 14 secured thereto by screws 13 (FIG. 3). The gear 14 has a vertical shaft 15 provided with an adjustment device 17 receiving a control cam 16. An intermediate shaft 19 pivoted within the frame 5 is drivingly connected to a motor 22 by means of a belt drive 21. The shaft 19 is connected via a clutch 18' and a belt drive 18 to the sewing head 1, and furthermore to the gear 14 by means of a belt drive 20. The control cam 16 is formed at its front surfaces with grooves 23, 24 cooperating with cam followers 25, 26 of the linkage 6. The vertical shaft 15 (FIG. 3) is provided with a reduced part 27 having a thread 29 carrying a key 28. The reduced part 27 receives a flange 30 rotatably secured by the key 28 and axially arrested at its lower part by resting against a shoulder 31 of the shaft 15. The control cam 16 is received on a front surface 32 of the flange 30 and secured against rotation by a pin 33 located in the flange 30 and reaching in a recess 34 of the control cam 16. Furthermore, the flange 30 is formed with a hub 35 adjustably receiving a first ring 36 which is provided with a cylindrical part 37 and a first conical part 38, both arranged with an eccentricity E 1 related to the inner bore which is not specified (FIG. 3). The cylindrical part 37 and the first conical part 38 serve for receiving a correspondingly formed second ring 39, which in turn is outwardly formed with a cylindrical part 40 and a second conical part 41 both arranged with an eccentricity E 2 related to its inner bore (not specified), i.e. to the parts 37 and 38 of the first ring 36.
The control cam 16 is formed with a mounting bore 42 corresponding to the cylindrical part 40 and the conical part 41 and including a cone 43. The control cam 16 is mounted by means of the front surface 32 of the flange 30, the first ring 36, the second ring 39, a washer 45 and a nut 44. As may be seen from FIG. 3, the rings 36 and 39 are formed with radial bores 46 and 47 respectively. According to FIGS. 3, 4 and 6 the vertical shaft 15 has an axis of rotation P whereas the physical axis of the control cam 16 is designated by R (FIGS. 4 and 6). According to FIG. 5, the rings 36, 39 are provided at their front surfaces 48, 49 with adjustment marks 50, 51 which cooperate with a further adjustment mark 52 of the control cam 16.
Operation of the adjustment device 17 will be described in conjunction with FIGS. 6, 7, 8 and 9 as follows:
As may be seen from the symbolic illustration in FIG. 9, the effective eccentricity E' and E" is achieved by respectively adjusting the rings 36 and 39, which are illustrated by their eccentricities E1 and E2 respectively. According to the designation of FIG. 4, the axis of rotation is marked by P, whereas the physical axis R of the control cam 16 is marked by R' or R" respectively. In FIG. 9 it is illustrated how the angular position of the effective eccentricity may be altered by turning the rings 36 or 39. When turning the eccentricity E2 (i.e. the second ring 39) about the center of rotation W, the direction of the effective eccentricity changes from line 54 to line 55 as the effective eccentricity simultaneously alters from E' to E".
For the following description it may be assumed that the workpiece receiving device 7 is positioned as the needle 9 corresponds to a point A (FIG. 7). According to this position, the cam follower 25 (FIG. 1) cooperating with the groove 23 may be assumed as being positioned on a corresponding beam A (FIG. 6). The control cam 16 is illustrated with further beams which refer to the sewing position AB, CD, EF and GH. Due to the function of the clutch 18' the workpiece receiving device 7 is moved to and from a basic position Y, prior to a sewing operation.
As may be seen from FIGS. 1 and 7, a movement of the workpiece receiving device 7 in the direction of the sewing head 1, i.e. in direction of an arrow 56, is achieved by the cooperation of the groove 23 and the cam follower 25. In conjunction with FIGS. 1, 6 and 7, it may be noticed that a lateral displacement of the control cam 16 by an amount of the dimension E increases the effective distance between the groove 25 and the axis of rotation P of the cam sections AB or CD, while the effective distance between the groove 23 and the axis of rotation P decreases at the cam sections EF or GH. Due to the described displacement of the control cam 16, the dimension a of the sewing portion AB will be increased as the dimension b of the sewing portion GH decreases. Accordingly, an alteration is achieved at the sewing portions CD or EF, i.e. an increase of the dimension c and a decrease of the dimension d.
The described adjustment of displacing the control cam 16 leads to closer distances of the sewing portions AB to GH or CD or EF, whereas an oppositely directed adjustment of the control cam 16 changes the conditions and leads to wider distances of the mentioned sewing portions.
FIG. 8 shows a patch pocket attached to a workpiece 8 by means of a single stitch row having sewing portions designated as KL and MN which are symbolized in FIG. 6 accordingly. Similarly as described above, the lateral displacement of the control cam 16 by an amount of the dimension E increases the effective distance between the groove section KL and the axis of rotation P, whereas the effective distance between the groove section MN and the axis of rotation P decreases. Due to the relative position of the sections KL and MN the effects are altered in such a way, that both dimensions e and f are increased by an equal amount. Consequently, the conditions change to the opposite, i.e. decreased dimensions e and f are achieved, by an opposite lateral displacement of the control cam 16. As described, the novel adjustment device allows adjusting the distance of the stitch portions KL-MN of a single-stitch-row attached pocket, i.e. size adjustment of the inner pocket dimensions.
For setting the adjustment device (FIGS. 3 and 5), the nut 44 must be loosened prior to turning the rings 36 and 39, for which the radial bores 46 and 47 are usable with a hooked wrench. The adjustment marks 51 help finding once experienced setting. In FIG. 5 the rings 36 and 39 are shown in a position 17/16. The pin 33 shown in FIGS. 3 and 4 serves as a torque-transmitting-element and prevents the rings 36 and 39 from rotating as the conical parts 38 and 41 allow a mounting of the control cam 16 without any play. | A sewing machine for producing a stitch pattern according to a predetermined program, in which a workpiece receiving device is driven by a linkage cooperating with a rotating control cam. An adjustment device makes it possible to affect portions of the stitch contour with respect to their relative position. The adjustment device has elements interposed between the control cam and the drive shaft for allowing a lateral displacement of the cam relatively to the drive shaft. The amount and the angular position of lateral adjustment may be achieved without rotating the cam and/or the drive shaft. | 3 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a driving circuit applied to a display system, and more particularly, to a driving with a protecting circuit to limit a high voltage surge introduced by parasitic inductance, driving method and associated display system.
[0003] 2. Description of the Prior Art
[0004] Refer to FIG. 1 , which is a diagram illustrating a display system 100 in the prior art. As shown in FIG. 1 , the display system 100 comprises a plurality of Light-Emitting Diodes (LED) D 1 to D N , a plurality of nodes N 1 to N N , a plurality of transistors M 1 to M N , and a plurality of current sources I 1 and I N , wherein the transistors M 1 to M N are controlled to be opened or closed by a plurality of Pulse Width Modulation (PWM) signals V en1 to V enN . The states of the transistors M 1 to M N change between open and close constantly by referring to the PWM signals V en1 to V enN to make the states of the LEDs D 1 to D N change between light-on and light-off constantly, and the average luminance of LEDs D 1 to D N are decided according to the time ratio of light-on state and light-off state of the LEDs D 1 to D N (i.e. the duty cycles of the PWM signals V en1 to V enN ).
[0005] Refer to FIG. 2 , which is an ideal waveform illustrating a voltage of the node N 1 and a current of the LED D 1 when the PWM signal V en1 changes to low level from the high level. As shown in FIG. 2 , when the PWM signal V en1 is on high level (e.g. 3V shown in FIG. 2 ), the transistor M 1 is conductive to make the LED D 1 have a current and illuminate. In this time, the voltage level of the node N 1 is 0V. Next, when the PWM signal V en1 decreases to 0V from 3V, the current of the LED D 1 decreases to OA due to the transistor M 1 is non-conductive (i.e. the LED D 1 does not illuminate). In this time, the voltage level of the node N 1 equals to a supple voltage V LED of the LED D 1 (e.g. 5V shown in FIG. 2 ).
[0006] However, because when the PWM signal V en1 decreases to low level from the high level to close the transistor M 1 , there is a parasitic inductance between the node N 1 and the LED D 1 , therefore, the node N 1 has a very high voltage surge and damages the circuit. FIG. 3 is a practical waveform illustrates the voltage of the node N 1 and the current of the LED D 1 when the PWM signal V en1 changes to low level from high level. As shown in FIG. 3 , the PWM signal V en1 decreases to 0V from 3V, the voltage level of the node N 1 suddenly jumps to a level close to 25V, in this way, the adjacent circuit of the node N 1 might be damaged and influences the circuit. In addition, with the increase of the frequency of the PWM signal V en1 , the above-mentioned voltage surge phenomenon might be more serious.
SUMMARY OF THE INVENTION
[0007] One of the objectives of the present invention is to provide a driving circuit with a protecting circuit to limit the high voltage surge introduced by parasitic inductance, a driving method and associated display system to solve the above-mentioned problems.
[0008] According to an embodiment of the present invention, a driving circuit applied in a display system comprises a node, a current control circuit, a protecting circuit and a timing controller, wherein the node is connected to a lighting element; the current control circuit is coupled to the node and arranged for selectively providing a current to the lighting element according to a PWN signal; the protecting circuit is coupled to the node and arranged for selectively enabling to limit the voltage of the node according to a control signal to make the voltage of the node maintain a predetermined voltage, wherein when the voltage of the node maintains the predetermined voltage, there is no current passes through the lighting element; and the timing controller is arranged for generating the PWM signal and the control signal.
[0009] According to another embodiment of the present invention, a driving method applied in a display system comprising: providing a driving circuit, wherein the driving circuit comprises a node arranged for connecting to a lighting element, a current control circuit coupled to the node and a protecting circuit coupled to the node; generating a PWM signal to the current control circuit to selectively provide a current to the lighting element generating a control signal to the protecting circuit to selectively enable the protecting circuit to limit the voltage of the node to make the voltage of the node maintain a predetermined voltage, wherein when the voltage of the node maintain a predetermined voltage, there is no current passes through the lighting element.
[0010] According to another embodiment of the present invention, a display system comprises a lighting element and a driving circuit, wherein the driving circuit comprises a node, a current circuit, a protecting circuit and a timing controller, wherein the node is arranged to connect to a lighting element; the current control circuit is coupled to the node and arranged for selectively providing a current to the lighting element according to a PWM signal; the protecting circuit is coupled to the node and arranged for selectively enabling to limit the voltage of the node according to a control signal to make the voltage of the node maintain a predetermined voltage, wherein when the voltage of the node maintains the predetermined voltage, there is no current passes through the lighting element; and the timing controller is arranged for generating the PWM signal and the control signal.
[0011] These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a diagram illustrating a display system in the prior art.
[0013] FIG. 2 is an ideal waveform illustrating a voltage of a node N 1 and a current of a LED D 1 when a PWM signal V en1 shown in FIG. 1 changes to low level from high level.
[0014] FIG. 3 is a practical waveform illustrating the voltage of the node N 1 and the current of the LED D 1 when the PWM signal V en1 shown in FIG. 1 changes to low level from high level.
[0015] FIG. 4 is a diagram illustrating a display system according to an embodiment of the present invention.
[0016] FIG. 5 is a diagram illustrating an input signal V s1 , an PWN signal V en1 and a control signal V c1 shown in FIG. 4 according to an embodiment of the present invention.
[0017] FIG. 6 is a practical waveform illustrating the voltage of the node N 1 and the current of the LED D 1 when the PWM signal V en1 shown in FIG. 4 changes to low level from high level.
[0018] FIG. 7 is a flowchart illustrating a driving method applied in a display system according to an embodiment of the present invention.
DETAILED DESCRIPTION
[0019] Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should not be interpreted as a close-ended term such as “consist of”. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
[0020] Refer to FIG. 4 , which is a diagram illustrating a display system 400 according to an embodiment of the present invention. As shown in FIG. 4 , the display system 400 comprises a plurality of lighting elements (in this embodiment, the lighting elements are LEDs D 1 to D N ) and a driving circuit 410 , wherein the LEDs D 1 to D N are coupled to the nodes N 1 to N N of the driving circuit 410 , respectively. The driving circuit 410 comprises a current control circuit 420 , a protecting circuit 430 and a timing controller 440 , wherein the current control circuit 420 comprises a plurality of transistors M 1 to M N and a plurality of current sources I 1 to I N , the protecting circuit 430 comprises a plurality of transistors M C1 to M CN , wherein the sources terminals of the plurality of transistors M C1 to M CN are connected to a supply voltage V LED of the LEDs D 1 to D N . In addition, in this embodiment, the driving circuit 410 is an independent chip.
[0021] In the operation of the system 400 , first of all, the timing controller 440 receives the input signals V S1 to V SN from the other elements of the driving circuit 410 , and the timing controller 440 generates the PWN signals V en1 to V enN and the control signals V c1 to V cN according to the input signals V S1 to V SN , wherein the PWN signals V en1 to V enN are arranged for controlling the transistor M 1 to M N of the current control circuit 420 to be opened or closed, respectively, and the average luminance of the LEDs D 1 to D N are determined by the time ratio of the open/close states of the transistor M 1 to M N , respectively (i.e. the duty cycles of the PWN signals V en1 to V enN ); and the control signals V c1 to V cN are arranged for controlling the open/close states of the transistors M C1 to M CN of the protecting circuit 430 to selectively limit the voltages of the node N 1 to N N .
[0022] More specifically, refer to FIG. 5 , which is a diagram illustrating the input signal V s1 , the PWN signal V en1 and the control signal V c1 according to an embodiment of the present invention. The first set of the input signal V s1 , the PWN signal V en1 and the control signal V c1 are used to be explained in FIG. 5 , however, the signals in FIG. 5 can be applied to other sets of input signal (V c2 to V cN ), PWM signals (V en2 to V enN ) and control signals (V c2 to V cN ). In the embodiment of FIG. 5 , the timing controller 440 delays the input signal V S1 to generate the PWM signal V en1 , wherein there is a delay Td between the PWM signal V en1 and the input signal V S1 , and the timing controller 440 performs inverting operation to the input signal V S1 to generate the control signal V C1 , in this way, before the PWM signal V en1 decreases to low level from high level (i.e. before the PWM signal V en1 closes the transistor M 1 to stop providing current to the LED D 1 ), the control signal V c1 opens the transistor M c1 in the protecting circuit 430 first, so the transistor M c1 in the protecting circuit 430 can discharge the charge stored in the node N 1 immediately when the node N 1 occurs the high voltage surge shown in FIG. 3 while the PWM signal V en1 decreasing to low level from high level to limit the voltage of the node N 1 to the supply voltage V LED , so the problem that the high voltage surge damages the circuit in prior art can be avoided.
[0023] In addition, before the PWM signal V en1 increase to high level from low level (i.e. before the PWM signal V en1 opens the transistor M 1 to provide current to the LED D 1 ), the control signal V c1 closes the transistor M c1 first to prevent the protecting circuit from forming another current path and affects the current value passed through the LED D 1 .
[0024] Refer to FIG. 6 , which is a practical waveform illustrating the voltage of the node N 1 and the current of the LED D 1 when the PWM signal V en1 changes to low level from high level. As shown in FIG. 6 , when the PWM signal V en1 decreases to 0V from 3V, the voltage level of the node N 1 can only reach 6V most, therefore, comparing with the 25V high voltage surge shown in FIG. 3 , the display system shown in FIG. 4 can improve the high voltage surge problem in circuit in the prior art indeed to prevent the circuit from damage.
[0025] In addition, according to the applicant, the architecture of the circuit in the protecting circuit 430 is only an example, not a limitation of the present invention. For example, the nodes of the transistors M C1 to M CN in the protecting circuit 430 can connect to another predetermined voltage instead of the supply voltage V LED . The predetermined voltage can be designed according to the requirement of the designer as long as the predetermined voltage can prevent the nodes N 1 to N N from being affected by the high voltage surge, and to make no current pass through the LEDs D 1 to D N , when the transistor M 1 to M N in the current control circuit 420 close. For example, the above-mentioned predetermined voltage can locate between (V LED −M*Vf) and (V LED +M*Vr), wherein M is the number of LED(s) of each LED string (M=1 in the embodiment of FIG. 4 ), Vf is a positive bias voltage of the LEDs D 1 to D N and Vr is a negative bias voltage of the LEDs D 1 to D N . In addition, the protecting circuit 430 is not necessarily to be implemented by the transistors M C1 to M CN . The protecting circuit 430 can be implemented in any other suitable architectures, as long as the protecting circuit 430 can provide a charge released path when the transistors M 1 to M N in the current control circuit 420 are closed to prevent the nodes N 1 to N N from high voltage surge, and the node N 1 to N N can maintain a suitable voltage level. These alternative designs should fall within the scope of the present invention.
[0026] In addition, the description about the timing controller 440 generating the PWM signals V en1 to V enN and the control signal V c1 to V cN described above, and the input signal V s1 , the PWM signal V en1 and the control signal V c1 shown in FIG. 5 are only explanation, not a limitation of the present invention. In other embodiments of the present invention, the timing controller 440 can input the input signals V s1 to V SN to the current control circuit 420 directly as the PWM signals V en1 to V enN , i.e. the delay Td between the PWM signal V en1 and the input signal V S1 as shown in FIG. 5 does not exist (i.e. the delay Td is very small). In the other words, the time that the PWM signal V en1 starts to close the transistor M 1 in the current control circuit 420 is very close or equal to the time that the control signal V c1 starts to open the transistor M c1 in the protecting circuit 430 . Additionally, the control V c1 can be generated in other ways to make the enable period Tp of the control signal V c1 shown in FIG. 5 can be reduced. These alternative designs should fall within the scope of the present invention.
[0027] In addition, the LEDs D 1 to D N shown in FIG. 4 are only an explanation. In other embodiments of the present invention, each of the LEDs D 1 to D N can be replaced with other lighting element or a LED string, wherein each LED string can comprise a plurality of LEDs. These alternative designs should fall within the scope of the present invention.
[0028] Refer to FIG. 7 , which is a flowchart illustrating a driving method applied in a display system according to an embodiment of the present invention. Refer to FIG. 4 and FIG. 7 , the flow is described as follows.
[0029] Step 700 : provide a driving circuit, wherein the driving circuit comprises a node arranged for connecting to a lighting element, a current control circuit coupled to the node and a protecting circuit coupled to the node.
[0030] Step 702 : generate a PWM signal to the current control circuit to selectively provide a current to the lighting element.
[0031] Step 704 : generate a control signal to the protecting circuit to selectively enable the protecting circuit to limit the voltage of the node.
[0032] Briefly summarized, in the driving circuit, the driving method and the associated display system of the present invention, a protecting circuit which can limit the high voltage surge introduced by parasitic inductance is provided. Therefore, by limiting the high voltage surge introduced by parasitic inductance, it can prevent the circuit from damage and does not affect the life of the circuit.
[0033] Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. | A driving circuit applied in a display system includes a node, a current control circuit, a protecting circuit and a timing controller, wherein the node is arranged to connect to a lighting element; the current control circuit is coupled to the node and arranged to selectively provide a current to the lighting element according to a Pulse Width Modulation (PWM) signal; the protecting circuit is coupled to the node and arranged to be selectively enabled to limit the voltage of the node according to a control signal to make the voltage of the node maintain a predetermined voltage, wherein the lighting element does not have any current passed through when the voltage of the node maintains the predetermined voltage; and the timing controller is arranged to generate the PWM signal and the control signal. | 7 |
BACKGROUND OF THE INVENTION
The present invention is related to the testing of integrated circuits and, more particularly, to measurement circuits of fuse elements in integrated circuits.
One type of fuse element is the antifuse, which is found in a growing number of integrated circuits, most of which are field programmable gate arrays (FPGAs). Antifuses have a very high resistance (to form essentially an open circuit) in the unprogrammed ("off") state, and a very low resistance (to form essentially a closed circuit) in the programmed ("on") state. In these integrated circuits antifuses are placed at the crossing points of interconnection lines which lead to different elements of the integrated circuit. By programming selected antifuses, the interconnections between the various elements of the integrated circuit are formed to define the function of the device.
To program these antifuses, a large voltage is placed across the selected antifuse. In the antifuse a nominally nonconducting programming layer, where two conducting lines cross, is melted to create a connection between the two conducting lines. The resistance of the unprogrammed antifuse, greater than 1 MegOhm, drops to tens of ohms, when programmed.
The description above is ideal. Problems may occur when the resistance of the programmed antifuse is not as low as desired. However, since the typical FPGA typically has hundreds of thousands of antifuses, it is difficult to locate a particular antifuse, and, once located, to test the antifuse.
The present invention solves or substantially mitigates these problems with test circuitry which is embedded in the integrated circuit to measure the resistance of a selected antifuse. In accordance with the present invention, the test circuitry is implemented in the integrated circuit with a minimum of overhead.
SUMMARY OF THE INVENTION
The present invention provides for an embedded test circuit in an integrated circuit. The integrated circuit has a plurality of conducting line segments and fuse elements therebetween with each fuse element selectively connected in series through the crossing line segments between a pair of programming terminals. Each fuse element is associated with a pair of test lines with each test line connected to one of the line segments having the fuse element between the two line segments. Each test line pair is selectively connected to a pair of test terminals. The resistance of a selected fuse element is measured by selectively passing a current between the first and second programming terminals through the selected fuse element and selectively measuring a voltage drop across the selected fuse element through the pair of test terminals. The testing may be performed as the fuse element is programmed, or after programming is completed.
BRIEF DESCRIPTION OF THE DRAWINGS
A more detailed understanding of the present invention may be achieved by perusing the following Detailed Description Of Preferred Embodiments of the present invention with reference to the following drawings:
FIG. 1 illustrates the general organization of an FPGA integrated circuit;
FIG. 2 is a detail of the test transistors and circuits with the wiring segments and the programming transistors to program an antifuse in a row in the core array of the FPGA in FIG. 1 in accordance with an embodiment of the present invention;
FIG. 3 illustrates the organization of the test circuits connected to the test transistors in the core array of the FPGA of FIG. 2; and
FIG. 4 is a circuit diagram of a transfer gate shown in FIG. 3.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1, a top view of an field programmable gate array (FPGA) integrated circuit, shows a general organizational layout of an FPGA. On a semiconductor substrate 10 the FPGA has a central core array 11, which can contain logic block elements, routing interconnections, and transistors, which may be interconnected by programmed antifuses for the user's application. Surrounding the core array 11 is a peripheral section 12, which contains the circuits for programming the antifuses in the core array 11, the control circuitry used for addressing the wiring segments in programming the selected antifuses, and the input/output circuitry for receiving signals from the outside world into the FPGA interior and for driving signals from the interior of the FPGA to the outside world.
The core array 11 is organized into repetitive rows 15 of the logic block elements, routing interconnections, and transistors, and along each row 15 the logic block elements, routing interconnections, and transistors are also organized into repetitive patterns. In FIG. 1 only five of the rows 15 are symbolically shown. Exemplary crossing line segments 21 and 22 are shown with an antifuse 20 connected therebetween. It should be understood that the entire core array 11 is organized into the rows 15.
Antifuses are placed where wiring segments cross in the rows 15. To connect two crossing wiring segments, the two wiring segments must be simultaneously and independently addressed. One wiring segment is driven to a high programming voltage, V pp , and the other wiring segment is driven to a low programming voltage, V pn . The difference between the two programming voltages across the antifuse at the intersection of the two segments programs the antifuse. As explained below, these programming voltages, V pp and V pn , are generated from programming pins connected to particular bonding pads during programming. This allows flexibility with respect to the particular programming voltages, but is not a requirement for the antifuse testing procedure according to the present invention. For example, V pn could be set to ground, rather to the voltage of the V pn programming pin.
FIG. 2 illustrates antifuse 20 between crossing wiring segments 22 and 21. In general, every wiring segment in the core array 11 is connected to large transistors for programming purposes. In the embodiment described, each wiring segment 22 or 21 is connected to a PMOS programming transistor 24 or a NMOS programming transistor 23. The PMOS programming transistor 24, connected to a + address circuit, drives the wiring segment to V pp during programming and the NMOS programming transistor 23, connected to a - address circuit, drives the segment to V pn during programming.
The +, or V pp , address circuit, and the -, or V pn , address circuit are two independent circuits for programming. Through the + address circuit and PMOS programming transistor 24, a + addressed wiring segment can be driven to V pp and is connected ultimately to a V pp pin (at +10 volts) of the FPGA integrated circuit during programming; through the - address circuit and NMOS programming transistor 23, the - addressed wiring segment can be driven to V pn and is connected ultimately to a V pn pin of the FPGA during programming.
As shown in FIG. 2, each of the + and - programming address circuits are separated into two parts. One part of the programming address circuits decodes address signals down to a bank of programming transistors connected to the wiring segments in a repetitive group of segments in a row 15. Thus these address signals, represented by +X, +Y for the + address circuit and -X, -Y for the - address circuit, select a number of PMOS programming transistors 24 (and their associated wiring segments 22) for the V pp programming voltage and NMOS programming transistors 23 (and their wiring segments 21) for the V pn programming voltage. The selection of the particular PMOS programming transistor 24 of the number selected by the +X, +Y address signals and NMOS programming transistor 23 of the number selected by the -X, -Y address signals is performed by connecting only one of the PMOS programming transistors 24 to V pp and only one of the NMOS transistors 23 to V pn .
Each wiring segment 22 and 21 is connected to a PMOS programming transistor 24 and a NMOS programming transistor 23 respectively. The + and - address decoding occurs on both the sources and gates of the programming transistors 24 and 23. The +X, +Y address signals are decoded for the gates of the PMOS programming transistors 24; this gate decoding function is represented by a NAND gate 26. The -X, -Y address signals are decoded for the gates of the NMOS programming transistors 23; this gate decoding function is represented by a NOR gate 25. For the + and - address decoding on the sources of the programming transistors, the source node of each PMOS programming transistor 24 is connected to one of a number of V pp voltage supplies in the form of + programming grids. Likewise, the source node of the NMOS programming transistor 23 is connected to one of a number of V pn voltage supplies also in the form of - programming grids.
Each programming grid is formed from metal lines which run horizontally in every row 15. Each grid is regularly cross-connected vertically. Grids are used, rather than only horizontal lines, to minimize the effective metal resistance between the source node of any programming transistor 24, 23 and the edge of the array 11 where the grids are connected to the V pp and V pn programming voltages. In this manner sufficient power can be delivered to any antifuse in the array 11 to program the antifuse.
The programming grids are not connected directly to the V pn and V pn power pins on the integrated circuit. Between the grids and the pins are many large transistors distributed around the periphery of the array 11. These peripheral programming transistors, represented by transistors 30 and 29 in FIG. 2, are connected such that during the programming of an antifuse, represented by the antifuse 20 in FIG. 2, only one + programming grid is connected to the V pp pin and only one - programming grid is connected to the V pn pin.
The remaining programming grids are at an intermediate voltage V pr , approximately +5 volts, which is obtained by a precharge operation prior to the programming of the selected antifuse. In the precharge operation, all of the + and - programming grids are set to +5 volts and all of the programming transistors are turned on and then turned off. Except for the isolation of elements in the CST rows 15 discussed below, all of the wiring segments are then left floating at +5 volts.
Further details of a particular FPGA programming circuitry is found in a U.S. Patent entitled, "A FIELD PROGRAMMABLE GATE ARRAY," U.S. Pat. No. 5,313,119 Laurence H. Cooke and David Marple, and assigned to the present assignee. But in all of FPGAs some form of decoding circuits is used to address the particular wiring segments to program the targeted antifuse.
The present invention takes advantage of these programming circuits. Associated with each programming transistor is a test transistor having the same polarity as the programming transistor. In FIG. 2 a PMOS test transistor 32 is associated with the PMOS programming transistor 24 and a NMOS test transistor 31 is associated with the NMOS programming transistor 23. Each test transistor 32, 31 has one source/drain connected to the same wiring segment 22, 21 as connected to the programming transistor 24, 23 respectively. The gate electrode of the test transistor 32, is connected to the gate electrode of the programming transistor 24, 23. Thus if the programming transistor 24, 23 is addressed, the associated test transistor 32, 31 is also addressed. The remaining source/drain of each test transistor 32, 31 is connected to a test line 42, 41 respectively.
The test transistors are very small, i.e., they have minimum width, since the test transistors 32, 31 are not required to carry any DC currents. In contrast, the programming transistors must carry heavy DC or AC currents to program the antifuses in the core array 11. For example, in one process technology a test transistor occupies approximately 2.5 μm 2 and a programming transistor occupies 60 μm 2 . Thus the test transistors occupy comparatively little space.
In the embodiment shown in FIG. 3, each row in the core array 11 has five test lines 42 from the PMOS test transistors 32 and four test lines 41 from the NMOS test transistors 31. On each side of the core array 11 is a set of peripheral test lines 73 and 74. Five PMOS peripheral test lines 44 run along the right side of the core array 11 and each PMOS test line 42 of each row 15 is connected to one of the PMOS peripheral test lines 44 through a PMOS pass transistor 34. Likewise, four NMOS peripheral test lines 43 run along the left side of the core array 11 and each NMOS test line 41 of each row 15 is connected to one of the NMOS peripheral test lines 43 through a NMOS pass transistor 33.
Each of the PMOS peripheral test lines 44 is connected by a peripheral transfer gate 36 to a single PMOS test output line 46 . The PMOS test output line 46 is, in turn, connected to a bonding pad 52 through a NMOS test mode transistor 38. Likewise, each of the NMOS peripheral test lines 43 is connected by a peripheral transfer gate 35 to a single NMOS test output line 45.
The NMOS test output line 75 is connected to a bonding pad 51 through a NMOS test mode transistor 37. To permit the bonding pads 52 and 51 to be used for more than one purpose, other circuits in the integrated circuit are connected to the bonding pads 52 and 51, as indicated in FIG. 3. During the testing of the antifuses, the test mode transistors 38 and 37 are turned on to connect the bonding pads 52 and 51 to the test circuitry described above. Otherwise, the pads 52 and 51 remain coupled to the other circuits, such as clock circuits, for example, by connection lines 48 and 47.
The circuit diagram of one of the transfer gates 36 and 35 is shown in FIG. 4. A single transistor might serve as a transfer gate where all the transistors in the test path are of the same polarity. Thus a single NMOS transistor may serve as one of the transfer gates 35, since all the other transistors 31, 33, and 37 from the line segment 41 to the pad 51 are NMOS transistors. Similarly, a single PMOS transistor could serve as one of the transfer gates 36 but for the NMOS test mode transistor 38. The NMOS PMOS circuit shown in FIG. 4 operates equally well whether all the transistors in the test path are of the same polarity or not.
Each of the transfer gates 36 and 35 has a PMOS transistor 54 and NMOS transistor 53 connected in parallel so that the source/drains of each of the transistors form part of the test path. Hence the source/drains of the PMOS and NMOS transistor 54 and 53 of a transfer gate 36 are respectively connected to a peripheral test line 44 and to the test output line 46. Similarly the source/drains of the PMOS and NMOS transistor 54 and 53 of a transfer gate 35 are respectively connected to a peripheral test line 43 and to the test output line 45. The gate electrodes of both transistors 54 and 53 are connected to the test address decoding circuits discussed immediately below. An inverter 55 shown in FIG. 4 indicates that the gate electrodes of both transistors 54 and 55 are connected to the test address decoding circuits in such a manner that both transistors are turned on at the same time. This may be done by connecting the gate electrodes of the transistors 54 and 53 to different nodes of the test address decoding circuits having opposite logic states at the same time, or using an inverter to invert the signal to one of the transistors 54 and 53.
Referring back to FIG. 3, PMOS test address decoding circuits are connected to each of the gate electrodes of the PMOS test transistors 34, transfer gates 36, and test mode transistors 38, and NMOS test address decoding circuits are connected to the gate electrodes of the NMOS test transistors 33, transfer gates 35, and test mode transistors 37. Together with the programming address decoding circuits for the test transistors 32 and 31, the test address decoding circuits select the particular wiring segments 22 and 21 for connection to the bonding pads 52 and 51. It should be noted that most of the decoding circuits for testing the antifuses of the FPGA reside in the programing decoding circuits, which are required to address each of the programming transistors 24 and 23 for the thousands of wiring segments in the core array 11. The test transistors 34 and 33, transfer gates 36 and 35, and test mode transistors 38 and 37 form only a fraction of the number of the programming transistors 24 and 23. Thus the added test circuits do not occupy as much space on, nor add as much complexity to, the integrated circuit as one might presume.
Of course, the design of decoding circuits for addressing functions are well known to integrated circuit designers. Note that the address signals for the decoding circuits may be transmitted in parallel through the multiple input pins of the integrated circuit. Alternatively, the signal addresses may serially scanned into the integrated circuit as suggested by the IEEE 1149.1 testing procedure. A particular testing procedure by serial scanning is described in U.S. Pat. No. 5,347,319 by Laurence H. Cooke et al. and assigned to the present assignee.
In operation, the present invention operates as follows. When an antifuse 20 is programmed, the programming transistors 24 and 23 of the crossing wiring segments 22 and 21 are turned on to program the selected antifuse 20. The programming address decoders also connect the selected programming transistors to one of two programming pins at one of the programming voltages, V pp or V pn . Thus the selected antifuse is subjected to a large programming voltage, V pp -V pn , with heavy programming currents.
For testing the selected antifuse, the programming pins are returned to standard operating voltages, such as +5 and 0 volts. The programming transistors 24 and 23 remain on so that the test transistors 32 and 31 associated with the programming transistors 24 and 23 are turned on also. Additionally, the test address signals which are used to identify the particular antifuse to be tested are used by test decoding circuits, PMOS and NMOS, to selectively connect the test transistors 32 and 31 to the pins connected to the bonding pads 52 and 51.
This permits a simple Kelvin test of the programmed antifuse 20. With a current through the selected antifuse 20, there is a voltage drop across the antifuse, which is monitored through the bonding pads 52 and 51 operating in test mode. Since the current is known, easily determined by an ammeter at one of the programming pins, the voltage drop across the selected antifuse as received on the bond pads 51 and 52 yields the resistance of the antifuse directly.
Thus this embedded test circuitry, which relies upon the existing programming circuits, permits simple and accurate measurements of the resistances of the antifuses of the FPGA.
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. For example, while the present invention was described in the context of antifuses, fuses should work equally as well. 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. | The present invention provides for an embedded test circuit in an integrated circuit. The integrated circuit has a plurality of conducting line segments and fuse elements therebetween with each fuse element selectively connectable in series through the crossing line segments and programming circuits between a pair of programming terminals. Each fuse element is also associated with a pair of test lines with each test line connected to one of the line segments having the fuse element between the test lines. Each test line pair is selectively connectable to a pair of test terminals. The resistance of a selected fuse element is measured by selectively passing a current between the first and second programming terminals through the selected fuse element and selectively measuring a voltage drop across the selected fuse element through the pair of test terminals. | 6 |
BACKGROUND OF THE INVENTION
In the alkaline pulping process, wood chips are digested in an aqueous pulping liquor containing sodium hydroxide. If the liquor also contains sodium sulfide, the process is kraft. After digestion is complete, the spent liquor (called black liquor) is concentrated by evaporation. The organic matter in the concentrated black liquor is then burned and the resulting smelt is dissolved in water to produce green liquor, which contains sodium carbonate. After being clarified, the green liquor is causticized by combining it with lime (calcium oxide) to convert the sodium carbonate to sodium hydroxide. The causticized liquor (called white liquor) is then used to digest more wood. This invention provides a more direct process for removing the organic matter in spent pulping liquor and regenerating the inorganic chemical values in the liquor.
SUMMARY OF THE INVENTION
In this invention the spent pulping liquor is converted directly into reusable pulping liquor containing sodium hydroxide. The invention involves pyrolyzing the liquor in the substantial absence of oxygen gas to produce a solid product containing sodium carbide and then quenching the product in water to produce the reusable liquor containing sodium hydroxide.
The liquor is preferably pyrolyzed by passing it through a zone of radiant energy having a temperature of at least 3000° F., preferably between about 3500° and 4500° F. The radiant energy preferably has a wave length in the near infrared region. The wave length is preferably between about one and two microns. Apparatus for providing a suitable zone of radiant energy is described in U.S. Pat. No. 4,095,974, which is incorporated herein by reference.
When subjected to near-infrared radiation, the carbon present in spent pulping liquor absorbs energy and reacts with, or promotes the reaction of, other chemicals in the liquor. For example, sodium carbonate is essentially transparent to radiation in the near-infrared region, and therefore would normally pass through the reaction zone unchanged, but when contacted with carbon black, the sodium carbonate decomposes into sodium oxide and carbon dioxide in accordance with the following equation:
Na.sub.2 CO.sub.3 →Na.sub.2 O+CO.sub.2
The sodium oxide reacts with the carbon to produce sodium carbide and carbon monoxide in accordance with the following equation:
Na.sub.2 O+3C→Na.sub.2 C.sub.2 +CO
And the carbon dioxide also reacts with the carbon to produce additional carbon monoxide in accordance with the following equation:
CO.sub.2 +C→2CO
Sodium sulfate present in the spent pulping liquor from the kraft process is reduced by carbon to sodium sulfide and carbon monoxide as follows:
Na.sub.2 SO.sub.4 +4C→Na.sub.2 S+4CO
Water in the pulping liquor reacts with the sodium oxide and carbon monoxide to produce sodium carbonate and hydrogen in accordance with the following equation:
H.sub.2 O+Na.sub.2 O+CO→Na.sub.2 CO.sub.3 +H.sub.2
This reconversion of sodium oxide to sodium carbonate detracts from the desired formation of sodium carbide. However, excess carbon will react with water to remove it from the system in accordance with the following equation:
C+H.sub.2 O→CO+H.sub.2
It is apparent from these reactions that it is desirable to have a stoichiometric excess of carbon and a minimal amount of water present. Hence, before the liquor is pyrolyzed, it is preferably concentrated so that it contains not more than about twenty-five percent water. To ensure a stoichiometric excess of carbon, a source of carbon, such as carbon black or sawdust, may be added to the liquor if desired. In any event, it is desirable to recycle to the reaction zone carbon present in the pyrolysis product.
The pyrolysis product contains sodium carbide, which is pyrophoric, so it should not be exposed to oxygen gas before being quenched with water. The sodium carbide reacts with the water to form sodium hydroxide and acetylene in accordance with the following equation:
Na.sub.2 C.sub.2 +2H.sub.2 O→2NaOH+C.sub.2 H.sub.2
The solid product leaving the zone of radiant energy may be separated from the gaseous product, such as by a cyclone, before the solid product is quenched with water, or the water may be added to the cyclone. The acetylene generated by the addition of water becomes part of the gaseous product, which may be used as a fuel gas.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block flow diagram of an embodiment of the process of this invention that was carried out experimentally.
FIG. 2 is a block flow diagram of an embodiment of the process of this invention that represents the best mode contemplated for practicing the invention.
DETAILED DESCRIPTION
Referring to the drawings, black liquor is fed to a reactor in which the liquor is pyrolyzed. A preferred reactor is shown in FIGS. 2A-6 of U.S. Pat. No. 4,095,974. As described therein, the reactor has a source of radiant energy, such as electrical resistance heating elements, which direct high-intensity radiant energy toward a reaction zone. The radiation is in the near-infrared region, and has a wave length of about one micron. An inert gas such as nitrogen is introduced into the reactor to provide an annular fluid wall surrounding the reaction zone. As the black liquor falls through the reaction zone, it absorbs radiant energy and is pyrolyzed in less than about one second.
The pyrolyzed material consists of solid product and gaseous product. The gaseous product may be drawn off and fed to a cyclone before the solid product drops into a water bath, as shown in FIG. 1. The cyclone removes larger particles of solid product entrained with the gaseous product before the gaseous product is fed to a baghouse, which removes finer particles of the solid product. The gas leaving the baghouse, which comprises principally carbon monoxide and minor amounts of carbon dioxide, hydrogen, and hydrocarbon gases, may be used as a fuel gas. The solid product leaving the baghouse may be combined with the product leaving the cyclone and the water bath to produce a recyclable pulping liquor.
FIG. 1 represents an embodiment of the process of the invention that was carried out experimentally. In a commercial operation, it is preferable to feed the pyrolysis product to a scrubber, as shown in FIG. 2. Water is introduced into the scrubber to separate the solid product from the gaseous product. The scrubbed gas is withdrawn as a fuel gas. The wetted solid product is withdrawn from the scrubber as a reusable pulping liquor containing sodium hydroxide resulting from reaction of the water with sodium carbide in the solid product. Insoluble material in the liquor, such as carbon, may be removed, such as by a filter, and recycled to the reactor.
This invention is applicable to any alkaline pulping process, i.e., any process using sodium hydroxide, but it is especially applicable to the kraft pulping process, which uses sodium sulfide in addition to sodium hydroxide.
The following example was carried out in accordance with the embodiment shown in FIG. 1. The reactor is shown in FIGS. 2A-6 of U.S. Pat. No. 4,095,974.
EXAMPLE
A mixture of about 84% by weight of dry black liquor (93% solids), 8% by weight of wood flour (about 10% moisture) and 8% by weight of carbon black was prepared. The mixture, which was free-flowing, was introduced into the reactor at a rate of 0.55 pounds per minute over a period of 20 minutes, for a total input of 11.0 pounds. Nitrogen was introduced into the reactor at a rate of 29.7 standard cubic feet per minute. The temperature inside the reactor was about 4000° F.
Pyrolyzed samples were collected at three points: a water-filled pan directly below the reactor, collecting approximately 50% of the total output sample; a water-filled cyclone collecting 20% of the sample, and a baghouse dropping its product into a water bath, representing 30% of the total output sample.
Collection of the pan solution was hampered by the floating of particulate material atop the water. This particulate material spontaneously ignited before it could be completely submerged, so the result of that portion of the sample may be biased in favor of a high Na 2 CO 3 reading.
Analysis of the sodium content of the three solutions for Na 2 S, NaOH, and Na 2 CO 3 were made.
______________________________________Percent of total Na in each sample as______________________________________ Na.sub.2 S NaOH Na.sub.2 CO.sub.3______________________________________Pan 14.8 23.3 59.8Cyclone 41.0 40.3 18.7Baghouse 38.5 48.8 12.7______________________________________Weighted percentage of Na in total sample(Pan = 50%, Cyclone = 20%, Baghouse = 30%)______________________________________ Na.sub.2 S 27.5 NaOH 34.4 Na.sub.2 CO.sub.3 37.5______________________________________
It can be seen from this example that even with the Na 2 CO 3 bias in collecting the product, almost 62% of the sodium was present as sodium sulfide and sodium hydroxide. | This invention is a process for recovering sodium hydroxide directly from black liquor. The process involves pyrolyzing the black liquor in the absence of oxygen to produce a product containing sodium carbide, and hydrolyzing the sodium carbide to form sodium hydroxide. The pyrolysis is carried out at about 4000° F. using radiant energy. | 8 |
This application is the U.S. national stage of International Application No. PCT/EP96/02542, filed Jun. 12, 1996 and designating the United States, which claims the priority of U.S. Provisional Patent Application No. 60/000,330, filed Jun. 19, 1995, now abandoned.
BACKGROUND OF THE INVENTION
I Field of the Invention
This invention relates to a new method of controlling fungi and weeds, and in particular it relates to a new method of protecting turf against both fungicidal diseases and weeds infestation.
II Discussion of the Prior Art
Protection of turf has always been a difficult problem because the users of turfs are generally very demanding people who require a top quality of the turf. The severe requirements are probably due to their aesthetic needs which are far away of the classical requirements of agricultural users such as farmers, who needs are directed to production considerations which do not involve anything on the appearance of the fields.
The difficulty of protecting turf is that there are generally and simultaneously both weeds infestations and fungicidal attacks which require both herbicidal and fungicidal treatments. The problem is thus made more difficult because, generally, the herbicidal compounds are not fungicidal and the fungicidal compounds are not herbicidal. Further it is generally necessary to strongly limit the number of treatment of turf because numerous passages of treatment machines may damage the turf so that this creates a third source of problem and increase the risks of impairing the said turf to an unacceptable level.
A further problem of turf care is the control of dollar spot disease (the causal agent for this disease being Sclerotinia homeocarpa). No single fungicidal compound is able to completely control this disease which is quite specific.
A still further problem of turf care is that the pesticidal treatment should be safe and not phytotoxic for the desired turfgrass, especially for one or more of the following grasses: Agrostis stolinifera, Festuca arundinacea, Festuca rubra, Lolium perenne, Poa pratensis and Poa annua.
Treatment of crops against weed infestation by isoxazoles is known, for example from European Patent Publication Nos. 0418175, 0487357, 0527036 and 0560482. However, no indication is known that these publications that isoxazoles could meet the above cited requirements with regard to the control of turf weeds. Furthermore, there is no indication that the isoxazoles possess any fungicidal properties.
An object of the invention is therefore to provide a method of protecting turf against fungicidal diseases.
A further object of the invention is to provide a method of protecting turf which is susceptible to be infested or contaminated by dollar spot disease.
A still further object of the invention is to provide a method of control of dollar spot disease on turf.
A still further object of the invention is to provide a method of control of dollar spot disease on turf which is safe for one or more of the grass species selected from the group comprising Festuca arundinacea, Festuca rubra, Lolium perenne, Poa pratensis and Poa annua.
A still further object of the invention is to provide a method of simultaneously controlling weeds and fungal infections found in turf.
A still further object of the invention is to overcome the existing problem of turf care, especially the problems as here above explained.
Surprisingly it has been found that these problems may be overcome in whole or in part by the method of the invention.
SUMMARY OF INVENTION
In one aspect the invention provides a method for the control of fungi at a locus which comprises applying to the locus an effective amount of an isoxazole derivative of formula I: ##STR2## wherein R is hydrogen or --CO 2 R 3 , wherein R 3 is as defined below;
R 1 is cyclopropyl;
R 2 is selected from halogen, --S(O) p R 4 , C 1-4 alkyl or C 1-4 haloalkyl;
n is two or three; p is zero, one or two;
R 3 is C 1-4 alkyl and
R 4 is C 1-4 alkyl.
DETAILED DESCRIPTION OF THE INVENTION
According to a specific aspect of the invention, the isoxazole is a herbicidally active isoxazole derivative.
Preferably R represents hydrogen.
Compounds of formula I above in which the groups (R 2 ) n are in the 2,4- or 2,3,4-positions of the benzoyl ring are also preferred.
Preferably R 2 is selected from the group consisting of halogen, --S(O) p R 4 and --CF 3 .
Preferably one of the groups R 2 represents --S(O) p R 4 , wherein R 4 is methyl.
The preferred compound of the invention is 5-cyclopropyl-4-(2-methylsulphonyl-4-trifluoromethyl)benzoylisozaxole, hereafter referred to as Compound 1.
In the method of the invention the locus is preferably an area comprising turfgrasses, in particular one or more of Festuca arundinacea, Festuca rubra, Lolium perenne, Poa pratensis and Poa annua.
The fungi controlled by the method of the invention is preferably dollar spot disease (Sclerotinia homeocarpa), which as mentioned above, is a particular problem of turfgrasses.
The method of the invention is preferably used under preventative conditions, i.e. when fungal infection of the locus is about to occur. It is also preferred to apply the isoxazole derivative of formula (I) above to established turfgrass areas.
The effective amount of isoxazole derivative which is used in the invention is generally from 80 to 300 g/ha, preferably from 100 to 230 g/ha.
Unless otherwise specified, the percentage cited in the instant specification are by weight.
The treatment of turf according to the invention is advantageously made by spraying a solid or liquid composition comprising the said isoxazole derivative.
The compositions which may be used in the invention for the fungicidal treatment of the invention are similar to the known herbicidally active compositions comprising an isoxazole derivative.
These compositions may comprise from 0.001 to 95% of the isoxazole derivative.
The liquid diluted formulations as applied to the turf comprise generally from 0.001 to 3% of isoxazole derivative, preferably from 0.1 to 0.5%.
The solid formulations as applied to the turf comprise generally from 0.1 to 8% of isoxazole derivative, preferably from 0.5 to 1.5%.
The concentrated compositions are the compositions which are commercialized or transported or stored. For application to plant they are normally diluted in water and applied in such a diluted form. The diluted form is part of the invention as well as the concentrated forms.
The concentrated formulations comprise generally from 5 to 95% of isoxazole derivative, preferably from 10 to 50%.
The compositions of the invention may be applied once, or more than once, or throughout the whole fungi season. Usually fungicidal compositions according to the invention are applied to the turf area at a rate of from 0.04 to 2 kg/ha of active ingredient, preferably from 0.1 to 1 kg/ha.
The fungicidal concentrated compositions according to the invention may be in the form of a solid, e.g. dusts or granules or wettable powders, or, preferably, in the form of a liquid, such as an emulsifiable concentrate or a true solution.
The fungicidal compositions according to the instant invention generally comprise from 0.5 to 95% of active ingredient. The remaining part up to 100% comprises a carrier as well as various additives such as those here after indicated.
By "carrier", it is herein meant an organic or inorganic material, which may be natural of artificial or synthetic, and which is associated to the active ingredients and which facilitates its application to the turf. This carrier is thus generally inert and should be agriculturally acceptable, especially on the contemplated or treated turf. The carrier may be solid (clay, silicates, silica, resins, wax, fertilizers, etc.) or liquid (water, alcohols, ketones, oil solvent, saturated or unsaturated hydrocarbons, chlorinated hydrocarbons, liquefied gas, etc.).
Among the many additives, the compositions of the invention may comprise surfactants as well as dispersants or stickers or antifoam agent or antifreezing agents or dyestuffs or thickeners, or adhesives or protecting colloids, penetrating agents, stabilizing agents, sequestering agents, antiflocculating agents, corrosion inhibitors, pigments, polymers.
More generally the compositions of the invention may comprise all kind of solid or liquid additives which are known in the art of fungicides and fungicidal treatments.
The surfactant may be emulsifying or wetting, ionic or non ionic. Possible surfactants are salts of polyacrylic or lignosulfonic acids, salts of phenolsulfonic or naphtalenesulfonic acids; polycondensates of ethylene oxide with fatty alcohols or fatty acids or fatty amines or substituted phenols (particularly alkylphenols or arylphenols); esters-salts of sulfosuccinic acids, taurine derivatives, such as alkyl taurates; Phosphoric esters of alcohols or polyoxyethylated phenols. The use of at least one surfactant is generally required because the active ingredients are not water soluble while the spraying vehicle is water.
The method of application of the compositions of the invention is generally the spraying of a mixture which has been previously made by dilution of more concentrated formulations according to the invention.
Solid compositions may powders for dusting or for dispersion and granule, especially extruded or compacted granules, or granules which have been made by impregnation of a powder (the content of active ingredients present in such powders will generally be from 1 to 80%).
Liquid compositions or compositions which have to be liquid when applied include solutions, water soluble concentrates emulsifiable concentrates, emulsions, wettable powders or pastes, water dispersible granules.
Emulsifiable concentrates comprise generally 10 to 80% of active ingredient; the emulsions when applied comprise generally 0.01 to 20% of active ingredient.
For example, the emulsifiable concentrates may comprise the solvent and further, as far as needed, 2 to 20% of suitable additives as stabilizers, surfactants, penetrating agents, corrosion inhibitors, or other additives already recited.
These concentrates are usually diluted in tank water so as to obtain the dilution appropriate for spraying.
The concentrated suspensions may also be applied by spraying and should be fluid without letting any solid to separate and falling at the bottom. Generally they comprise 1 to 75% of active ingredients (preferably 2 to 50%), 0.5 to 15% of surfactants, 0.1 to 10% of thickeners, 0 to 10% of other suitable additives as already indicated, and further water or an organic liquid wherein the active ingredient is insoluble or has a low solubility.
The wettable powders generally comprise the active ingredients (1 to 95%, preferably 2 to 80%), the solid carrier, a wetting agent (0 to 5%), a dispersing agent (3 to 10%) and, as far as needed, 0 to 10% of other additives such as stabilizers and other as already listed
In order to obtain these wettable powders or dusting powders, it is appropriate to intimately mix the active ingredients and the additives, to grind in a mill or similar devices.
Dispersible granules are generally made by agglomeration of a powder followed by an appropriate granulation process.
The emulsions herein described may be of type oil-in water or water-in-oil. They may more or less thick up to be like gels.
It will be understood that the composition or formulation used will vary depending to specific conditions of the treatment problem.
The compositions of the inventions may also be used in admixtures with another pesticide e.g. an insecticide, acaricide or herbicide.
The following are examples of representative compositions of the invention. In the description that follows the following are trade marks: REAX, Sellogen, Barden, Aerosil, Igepal, Rhodafac, Biodac.
EXAMPLE C1
The following composition was prepared as a wettable dispersible granule (the percentages that follow are by weight):
______________________________________Isoxazole derivative (Compound 1): 75.0% REAX 88A (Surfactant): 10.0% Sellogen HR (Surfactant): 3.0% Barden AG-1 (Clay): 11.0% Aerosil R972 (Silica filler) 1.0%______________________________________
EXAMPLE C2
The following composition was prepared as a granule (the percentages that follow are by weight):
______________________________________Isoxazole derivative (Compound 1): 0.38% Igepal CA630 (surfactant): 1.0% Rhodafac RE610 (surfactant): 1.0% N-methylpyrollidine (solvent) 7.0% Biodac (20/40) (synthetic granule) 90.62%______________________________________
The isoxazole derivatives used in the method of the invention are known from European Patent Publication Nos. 0418175, 0487357, 0527036 and 0560482, or can be prepared according to the methods described in these documents.
The invention is illustrated by the following examples which are not considered as limiting the invention but are given to better enable the skilled worker to use it.
EXAMPLE A1
The composition described in Example C1 above (100 g) was diluted in water (100 liters) and was sprayed on a 10 square meter turf stand in the Spring season. The application conditions were such that a dose rate equivalent to 202 grammes of Compound 1 per hectare was used, which corresponds to a concentration of Compound 1 of 390 ppm (parts per million).
The turf stand comprised a mixed population of creeping bentgrass (Agrostis stolinifera) and annual bluegrass (Poa annua). The stand was managed as a turf green and was mowed to a height of 4.75 mm. Contamination of this turf stand by dollar spot disease was from natural infection.
The results were noted by mean of the visual estimation of the number of fungi spots per square meter and transformed in a percentage of action by comparison with a similar untreated turf area. A 0% notation means that the treated turf was in the same conditions as the untreated standard. A 100% notation means that the treated turf was totally free of fungi disease.
91 days after treating the turf stand with the composition, an efficacy of 77.1% was observed.
103 days after treating the turf stand with the composition, an efficacy of 88.4% was observed.
EXAMPLE 2
Example 1 was repeated, except that the application conditions were such that a dose rate equivalent to 403 grammes of Compound per hectare was used, which corresponds to a concentration of Compound 1 of 780 ppm.
91 days after treating the turf stand with the composition, an efficacy of 93.3% was observed.
103 days after treating the turf stand with the composition, an efficacy of 95.2% was observed.
EXAMPLE 3
An in vitro study was set up to determine the ability of the compounds of the invention to inhibit the graph of Sclerotinia homoecarpa, the causal agent of dollar. A stock solution of Compound 1 technical material) in acetone was prepared. Potato dextrose agar (PDA) plates augmented with 10, 100 and 1000 ppm of Compound 1 were then made. Two sets of control plates were used; one contained corresponding amounts of acetone and the other contained PDA only. Four replicates were performed. An 8 mm diameter plug of fungal mycelia (Sclerotinia homoecarpa) was placed in the center of each plate, which were then incubated at room temperature for four days. As the growth of fungi on the untreated control reached the edge of the plates, the diameter of growth of the acetone control and the plates treated with Compound 1 were determined. The figures in the Table below represent the diameter of growth of the plug (Rep. means replicate number).
RESULTS
______________________________________ Acetone Control Compound 1Rep. PDA (ppm) (ppm)1 only 10 100 1000 10 100 1000______________________________________1 80 80 80 26 0 1 0 2 80 80 80 0 3 2 0 3 80 80 80 14 5 1 0 4 80 80 80 25 1 2 0______________________________________ | The invention relates to a method for the control of fungi at a locus which comprises applying to the locus a fungicidally effective amount of an isoxazole derivative of formula (I), wherein R is hydrogen or --CO 2 R 3 , wherein R 3 is as defined below, R 1 is cyclopropyl; R 2 is selected from halogen, --S(O) p R 4 and C 1-4 alkyl or haloalkyl; n is two or three; p is zero, one or two; R 3 is C 1-4 alkyl and R 4 is C 1-4 alkyl; and to compositions containing the same. ##STR1## | 0 |
FIELD OF THE INVENTION
The present invention relates to pharmaceuticals that affect cell adhesion, and more particularly, to a class of compounds that can inhibit or promote cell adhesion both in vitro and in vivo.
BACKGROUND OF THE INVENTION
Cell adhesion is one important property that differentiates multi-cellular organisms from simpler organisms such as bacteria. Cell adhesion is essential to the organization of higher organisms. Without cell adhesion, the organization of cells into tissues and tissues into organs would clearly be impossible. Likewise, the functioning of the immune system is also dependent on cell adhesion. Just as normal cell adhesion is essential to the normal functioning of higher organisms, abnormal cell adhesion is associated with a number of disease states such as intimation and cancer.
One manner in which cancer cells differ from normal tissue is in their cell adhesion and aggregation properties. Cell adhesiveness is one of the key cell surface-mediated properties that is altered during malignant transformation leading to metastatic dissemination of cancer cells. Metastasis is one of the most important malignant features of human cancer and represents the morphological stage of the generalization of the disease through the body of the tumor host. The abnormal adhesiveness of tumor cells is thought to contribute to the metastatic behavior of these cells. Implicit in the concept of metastasis is the separation of individual cells or small groups of cells from the primary tumor. It has been suggested that the intrinsically low adhesiveness of cancer cells contributes to separation. In particular, tumor cells have been shown to be more easily separated from solid tumors than are normal cells from corresponding tissues. Tumor cells have also been shown to be less adherent than normal cells to artificial substrates.
While the low adhesiveness of tumor cells contributes to the separation of cells from the primary tumor, metastasis is aided by the cells having some minimum degree of adhesion. The homotypic and heterotypic aggregation properties of tumor cells represent important biological features of malignancy because these properties of transformed cells contribute to the metastatic ability of neoplastic tumors. The concentration and size distribution of tumor cell clumps that enter the circulation play a significant role in the metastatic process. For example, intravenous injected tumor cells in clump form have a greater tendency to form metastases than do the same number of single tumor cells. Adhesion of cancer cells to other cells in circulatory system is required for the cancer cells to escape from the circulation system. Cancer cells that remain in the circulation system are known to have a very short lifetime. Hence, blocking of the homotypic and heterotypic adhesion of cancer cells can prevent escape of metastatic cells from the blood into the tissues and may cause a dramatic reduction or even complete prevention of metastasis.
The process of cell-cell recognition, association and aggregation consists of multiple steps, and a number of models of such a multistep process have been proposed. Generally the initial step is specific recognition between two cells in which multivalent homo-and heterotypic carbohydrate mediated interactions play a major role. Initial cell recognition through carbohydrate-carbohydrate or carbohydrate-protein (selectin) interaction is followed by protein-protein type adhesion, primarily mediated by Ca ++ -sensitive adhesion molecules such as cadherins, or by proteins of immunoglobulin superfamily, or by pericellular adhesive meshwork proteins consisting of fibronectin, laminin, and their receptor systems (integrin). The third step of cell adhesion is the establishment of intercellular junctions, e.g., "adherent junctions and "gap junctions," in which a cell-cell communication channel is opened through specific structural proteins, and specialized cellular contacts such as tight junctions and desmosomes are formed.
Structural determinants participating in the homotypic and heterotypic aggregation of histogenetically different types of cells may be the carbohydrate determinants of the blood-group antigen (BGA) related glycoantigens. Recently, the experimental evidences have been generalized that support the concept that some of the BGA-related glycodeterminants which have been identified earlier as tumor associated carbohydrate antigens (TACA) function as key adhesion molecules. The recent studies have shown that cell adhesion through carbohydrate-carbohydrate or carbohydrate-selectin interactions occur at early initial stage of "cascade" multistep cell adhesion mechanism, and this reaction is prerequisite for subsequent cell adhesion directed by integrin or immunoglobulin based adhesion. Usually cells co-express on their surface the multiple components involved in "cascade" cell adhesion mechanism, and thus, this multistep adhesion reaction could be triggered by initial carbohydrate--carbohydrate or carbohydrate-selectin interaction. Evidence has been presented that specific glycosphingolipid-glycosphingolipid interaction initiates cell-cell adhesion, and may cooperate synergistically with other cell adhesion systems such as those involving integrins.
Thus, the key features of cancer cells adhesion are the preservation of cell recognition function and the initial reversible steps of cell-cell or cell substrate adhesion and the impairment of the ability to display secondary stable attachment, strong adhesion, and terminal tissue specific cell-cell and cell-substrate contacts. The profound defects in protein adhesive systems primarily mediated by cadherin and integrin families of adhesion receptor is characteristic of malignant transformation and may contribute significantly to the abnormal locomotion, motility, invasion and metastasis of cancer cells. However, the acquisition of certain adhesive properties by malignant cells is extremely important for invasion, motility and metastasis. Typically, metastatic cancer cells lose the adhesive characteristics of their parent coherent tissues, but acquire adhesive properties similar to those of embryo and/or circulating normal cells (e.g. leukocytes and platelets).
Aberrant glycosylation of cell-membrane macromolecules is one of the universal phenotypic attributes of malignant tumors. A rather limited number of molecular probes based on monoclonal anticarbohydrate antibodies now enables the detection of over 90% of the most widespread human forms of cancer. One of the most important biological consequences of aberrant glycosylation is the expression of cell adhesion determinants on the surface of cancer cells. The most characteristic manifestation of aberrant glycosylation of cancer cells is neo-synthesis (or ectopic synthesis), the synthesis of incompatible antigens and incomplete synthesis (with or without the accumulation of precursors) of the BGA-related glycoepitopes. BGA-related glycoepitopes are directly involved in the homotypic (tumor cells, embryonal cells) and heterotypic (tumor cells-normal cells) formation of cellular aggregates (e.g., Lewis X antigens; H-antigens, polylactosamine sequences; and T-and Tn- antigens), which was demonstrated in different experimental systems. BGA-related alterations in the tissue glycosylation pattern are detected in benign (premalignant) tumors with risk of malignant transformation, in primary malignant tumors, and in metastases. Hence, they have been demonstrated as typical alterations in different stages of tumor progression. Therefore, the aberrant glycosylation in cancer is characterized by expression on the cell surface of tumor cells of certain BGA-related glycodeterminants. These changes were demonstrated as typical for different stages of tumor progression, including metastasis. The BGA-related glycodeterminants that are expressed on the surface of cancer cells function as cell adhesion molecules. They are present in cancer blood serum in biologically active form and may either stimulate or inhibit cell-cell interactions. The important fact is that in serum of all normal individuals circulate the naturally occurring anticarbohydrate antibodies of the same specificity.
The passage of metastatic cancer cells through blood and/or lymph compartment of host's body is one of the critical steps in metastatic dissemination of solid malignant neoplasms. Cancer cells that do not complete the transition quickly have exceedingly low survival rates in the circulatory system. There is a rapid phase of postintravasation (intramicrovascular) cancer cell death which is completed in less than 5 minutes and accounts for 85% of arrested cancer cells; this is followed by a slow phase of cell death, which accounts for the vast majority of the remainder. Mechanical trauma, which is a consequence of a shape transitions that occur when cancer cells enter and move along capillaries, has been considered as a most important factor contributing to the rapid death of the majority of cancer cells arrested in microvasculature of a different organs during metastatic dissemination.
Hence, inhibition of extravasation of cancer cells, blocking of their homotypic and heterotypic adhesion can prevent escape of metastatic cells from leaving the blood and entering the tissues. These considerations, as well as the analysis of cancer-related aberrations of cell adhesion mechanisms, suggest that agents that block cell adhesion may be of use in blocking metastasis. This therapy has been suggested as an additional complementary intervention for the current cancer treatment protocol, particularly designed to follow the surgical removal of a primary tumor.
The process of cell adhesion is also essential in the normal migration of cells. For example, in the healing of a wound, cells must migrate into the opening in the tissues in order to repair the opening. This cellular movement involves various classes of cells that move over the tissues surrounding the wound to reach the opening. Cellular adhesion is known to play a critical role in this type of cellular movement. Hence, compounds that enhance cellular adhesion are expected to enhance processes such as the healing of wounds. Similarly, the immune system both when functioning properly and in autoimmune diseases involves specific cellular adhesive reactions.
While potentially therapeutic compounds that affect cell adhesion are known, these compounds tend to be large macromolecules such as antibodies or peptides having carbohydrate moieties attached thereto. Maintaining such large structures in the circulatory system and/or targeting them to specific tissues presents a number of well known problems. In addition, the cost of manufacturing such compounds is quite high.
Broadly, it is the object of the present invention to provide an improved class of compounds that inhibit or enhance cell adhesion.
It is a further object of the present invention to provide cell adhesion affectors that consist of small molecular weight compounds.
It is a still further object of the present invention to provide cell adhesion affectors that may be synthesized using conventional chemical techniques.
It is yet another object of the present invention to provide cancer cell adhesion inhibitors that may be applied as antimetastatic agents.
These and other objects of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.
SUMMARY OF THE INVENTION
The present invention consists of a class of molecules that alter cell adhesion. A cell adhesion affector according to the present invention essentially consists of an amino acid linked to a carbohydrate wherein the amino acid and the carbohydrate are linked to form a compound chosen from the group consisting of Schiff bases, N-glycosides, esters, and Amadori products. The carbohydrate is preferably a monosaccharide or a small oligosaccharide. The carbohydrate and amino acid sub-units may be chemically modified. For example, the amino acid may be modified by covalently bonding other groups to the amino group, carboxyl group, or side chain group of the amino acid. The carbohydrate sub-unit is preferably a pentose such as arabinose, xylose, ribose, ribulose, a hexose such as fructose, deoxyfructose, galactose, glucose, mannose, tagatose, rhamnose, or a disaccharide based on two of the above such as maltose, lactose, maltulose, or lactulose.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the three types of compounds obtained from condensation reactions between glycine and glucose.
DETAILED DESCRIPTION OF THE INVENTION
The present invention comprises a class of compounds that either enhance or inhibit cellular adhesion, depending on the particular compound chosen and the target cell type. The simplest molecules in the class may be viewed as having two sub-units. The first sub-unit is an amino acid, and the second sub-unit is a carbohydrate. The amino acid may be joined to the carbohydrate by any condensation of the carbohydrate and the amino acid. For example, esters, Schiff bases, and Amadori compounds may be used. Here, the aldehyde group and/or one or more of the hydroxyl groups of the carbohydrate are substituted by the corresponding covalent bonding with the amino acid. As will become clear from the following discussion, compounds according to the present invention may be synthesized and purified via conventional organic chemical procedures; hence, the compounds of the present invention may be obtained at far less cost than other potential affectors of cell adhesion that require complex chemistry and/or fermentation to provide the chemicals or their precursors.
Refer now to FIG. 1 which illustrates the chemical reactions for the compounds according to the present invention that utilize the amino acid glycine and the sugar glucose. The condensation of a carboxyl group of an amino acid, namely glycine, with a hydroxyl group of carbohydrate, namely glucose, leads to the formation of an ester bond affording glycosyl amino acidate which is shown at 11. The amino acid-aldose condensation with the involvement of the amino and aldehyde groups occurs much more readily and may lead to the formation of Schiff bases (open chain of carbohydrate), or N-glycosides(12) (cyclic form of carbohydrate) with subsequent development of Amadori compound(13). It will be apparent to those skilled in the art that the glycine can be replaced by any amino acid in the scheme shown in FIG. 1, and the glucose can be replaced by any sugar.
Preparation of Amadori Compounds
The most stable class of condensation product of an amino acid and a carbohydrate is an Amadori compound. The Amadori compounds are the preferred compounds because of their high biological activity, stability, relative simplicity of synthesis, isolation and purification in large quantities. The synthesis of Amadori compounds may be carried out as follows: A suspension of 0.2 mol of sugar (e.g., anhydrous D-glucose, D-galactose or D-lactose monohydrate, etc.), 2.0 g sodium bisulfite in 60 mL of methanol and 30 mL of glycerol is refluxed for 30 min., followed by the addition of 0.05-0.09 mol of amino acid and 8 mL of acetic acid. This solution is refluxed until about 80% of the amino acid is reacted, as evidenced by TLC. The resulting brown, syrupy solution is diluted with 1 volume of water, placed on a 2 cm by 30 cm column of Amberlite IRN-77 ion exchange resin (hydrogen form) pretreated with 8 mL of pyridine. The column is eluted with water, followed by 0.2N ammonium hydroxide or, if necessary, by a buffer that was 0.2M in pyridine and 0.4M in acetic acid. Fractions of approximately 25 mL are collected. Early fractions contain D-glucose, uncharged pigments and D-glucose-derived degradation products. The Amadori compound usually elute next and are collected until the concentration becomes too low. The combined fractions, which contain Amadori compound, are evaporated to 100 mL in vacuo, decolorized with charcoal (2.0 g) and evaporated in vacuo at 30° C. to syrups.
Some of the Amadori compound, along with unreacted amino acid elute near the end of the water wash and at the beginning of the ammonium hydroxide wash. The combined fractions, which contain Amadori compound, are evaporated to 100 mL in vacuo and decolorized with charcoal (2.0 g). This solution is placed on a second 2 cm by 30 cm column of Amberlite IRN-77 (pyridinium form, pretreated with 10 mL of acetic acid). The column is eluted with water and 25 mL fractions collected. The Amadori compounds usually elute immediately. Fractions containing the desired products are evaporated in vacuo at 30° C. to syrups.
In the preferred embodiment of the present invention, the reaction conditions as well as separation and purification methodology of Amadori products may be optimized as follows: Methanol-glycerol mixture(s) as solvent provides the optimal reaction temperature (80° C.) at refluxing, necessary solubility for carbohydrates find amino acids, and dehydration conditions to shift the equilibrium toward the N-glycosides. Small amounts of acetic acid and sodium pyrosulfite are necessary to create optimal acidity of the reaction mixtures (pH ca. 5.0) to catalyze the Amadori rearrangement which competes with acid hydrolysis to the starting reagents and to optimize the reducing conditions (eliminating SO 2 ) to prevent oxidative browning of Amadori products. These conditions lead to over 90% conversion of starting amino acids if a 3-4 fold molar excess of carbohydrate is employed. The progress of the reaction may be readily monitored by TLC analysis using ninhydrin as the spray reagent.
The method of isolation of Amadori product from reaction mixture containing Amadori product, amino acid, sugars, and browning products is based on application of ion-exchange chromatography. The reaction mixture is diluted by water and then loaded on a cationite column in H± or pyH± form (for acid labile Amadori products). Amino acids, Amadori product and charged browning products are retained on ion-exchange resin, and noncharged compounds (solvent, sugar and majority of browning products) are eluted by water. The next elutents usually are the aqueous pyridine, acetic acid, ammonia and their mixture depending on individual properties of corresponding Amadori product and amino acid. The pH range is chosen to provide separation of Amadori product and amino acid on the column due to difference in their acid-base properties. The portion of eluate containing pure Amadori product is evaporated and residue crystallized from convenient solvent or mixture. In practice, pure final Amadori product (95% or more) with yield range of 10-40% from corresponding amino acid is obtained. The chromatographic and structural characterization of synthetic products may be performed using TLC, reversed, ion-exchange and normal-phase HPLC, FAB-MS, elemental analysis, NMR, amino acid and carbohydrate analysis, and pH-potentiometric analysis, optical rotation, X-ray analysis.
Preparation of Schiff Base Compounds
The sodium salts of the Schiff bases, compounds SSGA-22 through 30 (See Table I below), may be prepared by the following procedure. The appropriate amino acid (10 mmol) is added to a solution of 0.23 g (10 mmol) of metallic sodium in 80 mL of anhydrous methanol, and the suspension is then refluxed until all solid is dissolved. To the resulting solution, 10 mmol of carbohydrate is added and this mixture is stirred at 25° to 40° C. under inert atmosphere until the solution is clear. Dry diethyl ether (usually 200-400 mL) is then poured carefully into the reaction mixture under vigorous stirring to precipitate desired product as amorphous or microcrystalline mass. The product is separated with filtration, washed with ether and dried over CaCl 2 in vacuo.
Preparation of Ester Compounds
The synthesis of compounds SSGA-20, 21, 37, and 38 (See Table I below) as their hydrochlorides utilizes the following procedure: A solution of 5 mmol of Boc-amino acid, imidazole (1.02 g, 15 mmol) and anhydrous sugar (1.80 g, 10 mmol) in 60 mL of dry pyridine is prepared and cooled to 0° C. Dicyclohexylcarbodiimide (DCC, 1.03 g, 5 mmol) is then added and the reaction mixture is stirred in an ice bath for 4 hours and at room temperature for an additional 12 hours. A precipitate of dicyclohexylurea is filtered off and the filtrate is evaporated in vacuo. The residue is partitioned between ethyl acetate (40 mL) and cold 10% citric acid in water (40 mL). The organic layer is washed with water, dried over Na 2 SO 4 and evaporated in vacuo. The residue is crystallized from chloroform or methanol-chloroform, yielding the protected ester with 40-70% yield. This is dissolved in 15 mL of 1N solution of HCl in methanol or acetic acid and stirred at room temperature for an hour followed by addition of dry diethyl ether. The precipitate is collected by filtration and recrystallized from diethyl ether-THF.
The procedure for the synthesis of compounds SSGA-52 through 55 as their hydrochlorides utilizes the following procedure: To a solution of 5 mmol of Boc-amino acid and methyl α-D-glucopyranoside (1.94 g, 10 mmol) in 60 mL of dry acetonitrile a DCC (1.03 g, 5 mmol) is added at -1 0° C. The reaction mixture is stirred at 0° C. for 5 h and then overnight at room temperature. The protected ester is then isolated as described above with reference to SSGA-20, etc.
Modifications of the Basic Structure
In addition to the simple compounds consisting of an amino acid linked to a sugar, active compounds which are modifications of the basic structure have also been identified. These modifications may be separated into four classes. The first class involves the substitution of a small polypeptide for the amino acid. The second group involves substituting a polysaccharide for the sugar. The third class involves optical isomerization of an amino acid or modifications to the amino group, carboxyl group, hydrocarbon chains, or side chain group of the amino acids by covalently bonding other groups to one or more of these groups. Compounds SSGA-8, SSGA-13, SSGA-45, SSGA-10 and SSGA-39 belong to this class. Finally, one or more hydroxyl groups of the carbohydrate may be modified. For example, the hydroxyl group of the compounds based on D-glucose may be modified methylated to form compounds such as methyl α-D-glucopyranoside. Compounds SSGA-52 through SSGA-54 belong to this fourth class. For the purposes of the following discussion, the simplest class of molecules consisting of an amino acid coupled to a sugar will be referred to as the basic class.
Exemplary Compounds
Fifty-five members of the basic class or modifications thereof have been synthesized and all of these can be shown to affect cell adhesion in one or more cell adhesion assays. A summary of the chemical compounds investigated to date is given in Table I, below. The corresponding amino acid, method of linkage, and carbohydrate for a compound may be deduced from the compound's name. The full chemical name of each of the compounds listed in Table I may be found in Table II, below. Compounds SSGA-1 through SSGA-19, SSGA-31 through SSGA-36, and SSGA-39 through 51 are Amadori compounds. Compounds SSGA-22 through 30 are Schiff bases. Compounds SSGA-20, SSGA-21, SSGA-37, SSGA-38, and SSGA-52 through SSGA-55 are glycosyl esters of amino acids.
Some of the members of this group promote cell adhesion and some inhibit cell adhesion. In addition, some members promote cell adhesion in one cell type and inhibit cell adhesion in other cell types. The specific effect produced depends on the type of amino acid, sugar, coupling bond and the target cell type.
TABLE 1__________________________________________________________________________Names of Synthetic Glycoamine Structural Analog__________________________________________________________________________SSGA-1 N-(1-Deoxy-D-fructos-1-yl)-β-alanineSSGA-2 N-(1-Deoxy-D-fructos-1-yl)-glycineSSGA-3 N-(1-Deoxy-D-fructos-1-yl)-L-phenylalanineSSGA-4 N-(1-Deoxy-D-fructos-1-yl)-L-tyrosineSSGA-5 N-(1-Deoxy-D-fructos-1-yl)-L-isoleucineSSGA-6 N-(1-Deoxy-D-fructos-1-yl)-L-aspartic acidSSGA-7 N-(1-Deoxy-D-fructos-1-yl)-L-glutamic acidSSGA-8 N-ε-(1-Deoxy-D-fructos-1-yl)-N-α-formyl-L-lysineSSGA-9 N-(1-Deoxy-D-fructos-1-yl)-γ-aminobutyric acidSSGA-10 N-(1-Deoxy-D-fructos-1-yl)-ε-aminocaproic acidSSGA-11 N-(1-Deoxy-D-fructos-1-yl)-L-tryptophanSSGA-12 N-(1-Deoxy-D-fructos-1-yl)-L-leucineSSGA-13 N-(1-Deoxy-D-fructos-1-yl)-D-leucineSSGA-14 N-(1-Deoxy-D-fructos-1-yl)-L-alanineSSGA-15 N-(1-Deoxy-D-fructos-1-yl)-L-valineSSGA-16 N-(1-Deoxy-D-fructos-1-yl)-L-prolineSSGA-17 N-(1-Deoxy-D-tagatos-1-yl)-L-leucineSSGA-18 N-(1-Deoxy-D-maltulos-1-yl)-L-leucineSSGA-19 N-(1-Deoxy-D-lactulos-1-yl)-L-leucineSSGA-20 6-O-(L-Prolyl)-D-glucoseSSGA-21 6-O-(L-Phenylalanyl)-D-glucoseSSGA-22 N-(1-Deoxy-D-glucos-1-yl)-L-proline Na-saltSSGA-23 N-(1-Deoxy-D-glucos-1-yl)-L-phenylalanine Na-saltSSGA-24 N-(1-Deoxy-L-rhamnos-1-yl)-L-alanine Na-saltSSGA-25 N-(1-Deoxy-D-galactos-1-yl)-L-alanine Na-saltSSGA-26 N-(1-Deoxy-D-glucos-1-yl)-L-alanine Na-saltSSGA-27 N-(1-Deoxy-D-mannos-1-yl)-L-alanine Na-saltSSGA-28 N-(1-Deoxy-L--arabinos-1-yl)-L-alanine Na-saltSSGA-29 N-(1-Deoxy-D-maltos-1-yl)-L-alanine Na-saltSSGA-30 N-(1-Deoxy-D-xylos-1-yl)-L-alanine Na-saltSSGA-31 N-(1-Deoxy-D-ribulos-1-yl)-L-phenylalanineSSGA-32 N-(1-Deoxy-D-fructos-1-yl)-L-threonineSSGA-33 N-(1-Deoxy-D-maltulos-1-yl)-L-phenylalanineSSGA-34 N-(1,6-Dideoxy-L-fructos-1-yl)-L-prolineSSGA-35 N-(1-Deoxy-D-tagatos-1-yl)-L-phenylalanineSSGA-36 N-(1-Deoxy-D-lactulos-1-yl)-L-phenylalanineSSGA-37 6-O-(L-Valyl)-D-mannoseSSGA-38 6-O-(L-Prolyl)-D-galactoseSSGA-39 N-(1-Deoxy-D-fructos-1-yl)-δ-aminovaleric acidSSGA-40 N-(1-Deoxy-D-fructos-1-yl)-L-serineSSGA-41 N-(1-Deoxy-D-lactulos-1-yl)-L-prolineSSGA-42 N-(1-Deoxy-D-lactulos-1-yl)-L-valineSSGA-43 N-(1-Deoxy-D-fructos-1-yl)-L-methionineSSGA-44 N,N'-Di (1-deoxy-D-fructos-1-yl)-L-lysineSSGA-45 N-α-(1-Deoxy-D-fructos-1-yl)-N-ε-formyl-L-lysineSSGA-46 N-α-(1-Deoxy-D-fructos-1-yl)-L-asparagineSSGA-47 N-(1-Deoxy-D-fructos-1-yl)-L-hydroxyprolineSSGA-48 N-(1-Deoxy-D-tagatos-1-yl)-L-prolineSSGA-49 N-(1-Deoxy-D-tagatos-1-yl)-L-valineSSGA-50 N'-α-(1-Deoxy-D-fructos-1-yl)-L-histidineSSGA-51 N,N-Di(1-deoxy-D-fructos-1-yl)-glycineSSGA-52 Methyl 6-O-(glycyl)-α-D-glucopyranosideSSGA-53 Methyl 2,3,4-tri-O-(glycyl)-6-O-(L-alanyl)-α-D-glucopyranoside 3SSGA-54 Methyl 6-O-(L-alanyl)-α-D-glucopyranosideSSGA-55 Methyl 2,3,-di-O-(L-alanyl)-α-D-glucopyranoside__________________________________________________________________________
TABLE II__________________________________________________________________________Full systematic names of synthetic glycoamine structural__________________________________________________________________________analogs.SSGA-1N-(1-Deoxy-D-arabino-hexulos-1-yl)-3-aminopropanoic acidSSGA-2N-(1-Deoxy-D-arabino-hexulos-1-yl)-aminoetanoic acidSSGA-3N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-amino-3-phenylpropanoicacidSSGA-4N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-amino-3-(4-hydroxyphenyl)-propanoic acidSSGA-5N-(1-Deoxy-D-arabino-hexulos-1-yl)-(2S,3S)-2-amino-3-methylpentanoic.acidSSGA-6N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-aminobutane-1,4-dioic acidSSGA-7N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-aminopentane-1,5-dioicacidSSGA-8(S)-6-(1-Deoxy-D-arabino-hexulos-1-amino)-2-N-formylaminohexanoicacidSSGA-9N-(1-Deoxy-D-arabino-hexulos-1-yl)-4-aminobutanoic acidSSGA-10N-(1-Deoxy-D-arabino-hexulos-1-yl)-6-aminohexanoic acidSSGA-11(S)-2-(1-Deoxy-D-arabino-hexulos-1-amino)-3-(indol-3-yl)-propanoicacidSSGA-12N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-amino-4-methylpentanoicacidSSGA-13N-(1-Deoxy-D-arabino-hexulos-1-yl)-(R)-2-amino-4-methylpentanoicacidSSGA-14N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-aminopropanoic acidSSGA-15N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-amino-3-methylbutanoicacidSSGA-16(S)-1-(1-Deoxy-D-arabino-hexulos-1-yl)-2-pyrrolidine carboxylicacidSSGA-17N-(1-Deoxy-D-lyxo-hexulos-1-yl)-(S)-2-amino-4-methylpentanoic acidSSGA-18N-(1-Deoxy-4-O-(α-D-glucopyranos-1-yl)-D-arabino-hexulos-1-yl)-(S)-2-amino-4-methylpentanoic acidSSGA-19N-(1-Deoxy-4-O-(β-D-galactopyranos-1-yl)-D-arabino-hexulos-1-yl)-(S)-2-amino-4-methylpentanoic acidSSGA-206-O-((S)-2-pyrrolidine carboxyl)-D-glucoseSSGA-216-O-((S)-2-amino-3-phenylpropanoyl)-D-glucoseSSGA-22(S)-1-(1-Deoxy-D-glucos-1-yl)-2-pyrrolidine carboxylic acidSSGA-23N-(1-Deoxy-D-glucos-1-yl)-(S)-2-amino-3-phenylpropanoic acidSSGA-24N-(1,6-Dideoxy-L-mannos-1-yl)-(S)-2-aminopropanoic acidSSGA-25N-(1-Deoxy-D-galactos-1-yl)-(S)-2-aminopropanoic acidSSGA-26N-(1-Deoxy-D-glucos-1-yl)-(S)-2-aminopropanoic acidSSGA-27N-(1-Deoxy-D-mannos-1-yl)-(S)-2-aminopropanoic acidSSGA-28N-(1-Deoxy-L-arabinos-1-yl)-(S)-2-aminopropanoic acidSSGA-29N-(1-Deoxy-4-O-(a-D-glucopyranos-1-yl)-D-glucos-1-yl)-(S)-2-aminopropanoic acidSSGA-30N-(1-Deoxy-D-xylos-1-yl)-(S)-2-aminopropanoic acidSSGA-31N-(1-Deoxy-D-erythro-pentulos-1-yl)-(S)-2-amino-3-phenylpropanoicacidSSGA-32N-(1-Deoxy-D-arabino-hexulos-1-yl)-(2S,3R)-2-amino-3-hydroxybutanoicacidSSGA-33N-(1-Deoxy-4-O-(α-D-glucopyranos-1-yl)-D-arabino-hexulos-1-yl)-(S)-2-amino-3-phenylpropanoic acidSSGA-34(S)-1-(1,6-Dideoxy-L-arabino-hexulos-1-yl)-2-pyrrolidine carboxylicacidSSGA-35N-(1-Deoxy-D-lyxo-hexulos-1-yl)-(S)-amino-3-phenylpropanoic acidSSGA-36N-(1-Deoxy-4-O-(β-D-galactopyranos-1-yl)-D-arabino-hexulos-1-yl)-(S)-2-amino-3-phenylpropanoic acidSSGA-376-O-((S)-2-amino-3-methylbutanoyl)-D-mannoseSSGA-386-O-((S)-2-pyrrolidine carboxyl)-D-galactoseSSGA-39N-(1-Deoxy-D-arabino-hexulos-1-yl)-5-aminopentanoic acidSSGA-40N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-amino-3-hydroxypropanoicacidSSGA-41(S)-1-(1-Deoxy-4-O-(β-D-galactopyranos-1-yl)-D-arabino-hexulos-1-yl)-2-pyrrolidine carboxylic acidSSGA-42N-(1-Deoxy-4-O-(β-D-galactopyranos-1-yl)-D-arabino-hexulos-1-yl)-(S)-2-amino-3-methylbutanoic acidSSGA-43N-(1-Deoxy-D-arabino-hexulos-1-yl)-(S)-2-amino-4-methylthiobutanoicacidSSGA-44N,N'-Di(1-deoxy-D-arabino-hexulos-1-yl)-(S)-2,6-diaminohexanoicacidSSGA-45(S)-2-(1 -Deoxy-D-arabino-hexulos-1-amino)-6-N-formylaminohexanoicacidSSGA-46(S)-3-(1-Deoxy-D-arabino-hexulos-1-amino)-3-carboxypropanamideSSGA-47(2S,4R)-1-(1-Deoxy-D-arabino-hexulos-1-yl)-4-hydroxy-2-pyrrolidinecarboxylic acidSSGA-48(S)-1-(1-Deoxy-D-lyxo-hexulos-1-yl)-2-pyrrolidine carboxylic acidSSGA-49N-(1-Deoxy-D-lyxo-hexulos-1-yl)-(S)-2-amino-3-methylbutanoic acidSSGA-50(S)-2-(1 -Deoxy-D-arabino-hexulos-1-amino)-3-(1H-imidazol-4-yl)-propanoic acidSSGA-51N,N-Di(1-deoxy-D-arabino-hexulos-1-yl)-aminoetanoic acidSSGA-52Methyl 6-O-(2-aminoethanoyl)-α-D-glucopyranosideSSGA-53Methyl 2,3,4-tri-O-(2-aminoethanoyl)-6-O-((S)-2-aminopropanoyl)-.alpha.-D-glucopyranosideSSGA-54Methyl 6-O-((S)-2-aminopropanoyl)-α-D-glucopyranosideSSGA-55Methyl 2,3-di-O-((S)-2-aminopropanoyl)-α-D-glucopyranoside__________________________________________________________________________
Biological Activity
The compounds listed in Table I have been tested in one or more of a panel of 9 assays for their ability to promote or inhibit cell adhesion. The test results are summarized in Table III. The panel of tests can be divided into three classes of tests. In the first class of tests, (Tests 1-4 in Table III), the ability of a compound according to the present invention to inhibit or promote cell adhesion as measured by an in vitro Murine cancer assay was determined, this test will be referred to as the cell aggregation assay in the following discussion. Tumor cells were obtained from the indicated tumor tissue by standard trypsinization procedures. Then, 10 6 cells were cultured at 37° C. in 5% CO 2 by using RPM1 1640 containing 10% fetal calf serum, 2 mM glutamine, and 1 mM pyruvate, 100 IU of penicillin per mL, 20 mg of gentamicin per mL, and 100 IU of streptomycin per mL (growth medium). The cells were cultured with and without a adhesion affector according to the present invention. The concentration range for the tested compounds was 20 μM to 15 mM. The cells were incubated for periods of 24-72 hours and 5 days in 0.4-1.0 mL (final volume) of growth medium in wells of a 96-well cell culture plate. The aggregates containing more than 4-5 cells (in suspension and substrate-attached) in each well were counted. Live cell counts were obtained by trypan blue dye exclusion.
The second class of assay (Tests 5-7 in Table III) involves the measurement of metastatic activity in vivo. The assay was carried out as follows: Cancer cells of the indicated type were incubated for 1 hour in 5% CO 2 at 37° C. in RPMI-1640 medium with and without addition of 1 mM (final concentration) of tested compounds. Subsequently 2.10 5 melanoma or carcinoma cells were injected into tail vein of C57B1 2-3 month old male mice and 21 days later, the lung metastases were counted. Similarly, 0.25.10 6 fibrosarcoma cells were injected into the tail vein of BALB/c 8-10 week old male mice and 21 days later, the lung metastases counted. All three general inhibitors of in vitro cancer cell aggregation showed a significant inhibition of in vivo experimental lung metastasis after intravenous inoculation of B16 melanoma cells. SSGA-12 and SSGA-13 have caused a 70% and 71% inhibition of lung colonization, respectively. Inhibition of B16 melanoma lung metastasis also showed that synthetic compound SSGA-19 was inhibitory with a 63% of inhibition of lung colonization. The 2 most effective synthetic inhibitors of in vitro melanoma cell aggregation also inhibited lung metastasis the most. SSGA-9 and SSGA-10 inhibited the lung colonization by melanoma cells at 79% and 87%, respectively. For comparison, SSGA-5 which is not an inhibitor of the B16 melanoma cell line in the in vitro aggregation test is only a weak inhibitor in vivo. SSGA-5 inhibited lung colonization only 35% in the above described assay.
The third class of assays (Tests 8-9 in Table III) will be referred to as the in vitro human cancer assay. The MDA-MB-435 human breast carcinoma cell line was isolated originally from pleural effusion of a patient with breast carcinoma and was found to be highly metastatic from the mammary fat pad (m.f.p.) tumors as well as after i.v. injection in nude mice.
The TXM-13 human melanoma cell line were originally isolated from brain metastases and were established from surgical specimens from melanoma patients at The University of Texas M.D. Anderson Cancer Center (Houston, Tex.). TXM-13 human melanoma cell line was found to be highly tumorigenic and metastatic in nude mice.
The metastatic and tumorigenic properties of human melanoma and breast carcinoma cell lines in nude mice were found to correspond well with their colony-forming efficiency in dense agarose. Hence, the tests were carried on agarose.
The tumor cells were maintained in tissue culture in minimum essential medium (MEM) supplemented with 5 or 10% fetal bovine serum (FBS), sodium pyruvate, nonessential amino acids, L-glutamine, and 2-fold vitamin solution (Gibco, Grand Island, N.Y.). The cultures were maintained on plastic and incubated in 5% CO 2 -95% air at 37° C. in a humidified incubator. All cultures were free of Mycoplasma and the following murine viruses: reovirus type 3; pneumonia virus; K virus; Theiler's encephalitis virus; Sendai Virus; minute virus; mouse adenovirus; mouse hepatitis virus; lymphocytic choriomeningitis virus; ectromelia virus; lactate dehydrogenase virus (all assayed by MA Bioproducts, Walkersville, Md.).
The Agarose cultures used in the assays were prepared as follows: Agarose (Sigma Chemical Co. St. Louis, Mo.) was dissolved in distilled water and autoclaved at 120° C. for 20 min. MEM with 10% FBS and 0.6% agarose was plated in 30-mm-diameter plastic dishes to provide a base layer (1 mL per dish). Suspensions of breast carcinoma cells were filtered through 20 mm Nitex nylon mesh (Tetko, Elmsford, N.Y.) to remove any clumps of cells and then mixed with MEM containing 10% FBS (20% FBS for cultures of MDA-MB-361 cells) and different concentrations of agarose. This mixture was overlaid on the base layers. The cell number per dish in 1.5 mL was 5×10 3 for cultures of 0.3 and 0.6% agarose, 10 4 cells in 0.9% agarose, and 2×10 4 cells in 1.2% agarose. The culture dishes were incubated at 37° C. in a humidified incubator in a 5% CO 2 -95% air atmosphere. The numbers and diameters of tumor colonies examined 30 days after plating were determined using a microscope equipped with a Filar micrometer (Cambridge Instruments, Deer Lake, Ill.).
The MDA-MB-435 inhibition of colony formation in agarose assay was carded out as follows: Cells were incubated for 1 h at 37° C. in the presence of compound at 0.6 to 10 mM, then mixed with agarose to achieve a final concentration of 0.3 or 0.9% and plated in 35 mm wells. Colonies of diameter greater than 50 μm were counted at 14 days (0.3% agarose) of 21-25 days (0.9% agarose). Percent inhibition was calculated by comparison with colony numbers in control cultures (cells incubated with medium alone).
The TXM-13 inhibition of colony formation in agarose test was carried out as follows. TXM- 13 human melanoma cells were plated in agarose following incubation for one hour with the compounds at 0.6 to 10 mM. The assays for activity of compounds #9 and #10 produced low colony numbers in control and test groups (inoculum of 5×10 3 per dish in 0.3% agarose and 10 4 per dish in 0.9% agarose). Cell inoculum was increased (x 2) for the other experiments, producing larger colony numbers. Colony numbers were counted on day 21-25 after plating.
TABLE III__________________________________________________________________________Summary of testing of the synthetic structural analogs of glycoamines. Human Murine cancer, in vitro Murine cancer, in cancer, inCompound assay vivo assay vitro assaynumber 1 2 3 4 5 6 7 8 9__________________________________________________________________________SSGA-1 ++ ++ -- + ++ ++ ++SSGA-2 ++ + -- 0 0 ++ ++SSGA-3 ++ ++ ++ 0 ++ ++ ++SSGA-4 ++ - -- 0SSGA-5 ++ -- - + 0 0SSGA-6 ++ - -- 0 0SSGA-7 0 ++SSGA-8 0 ++ + 0SSGA-9 - - ++ + 0 ++ 0 0SSGA-10 - ++ ++ + ++ ++ 0SSGA-11 ++SSGA-12 + + + ++ ++ ++ ++ ++SSGA-13 ++ ++ + ++ ++ ++ ++ ++ ++SSGA-14 ++ - + + ++SSGA-15 0 0 + 0SSGA-16 ++ 0 0 ++ ++SSGA-17 ++ -- ++ ++SSGA-18 ++ ++ 0SSGA-19 + ++ + ++ ++ ++ ++ ++SSGA-20 ++ + ++SSGA-21 ++ 0SSGA-22 ++ 0 --SSGA-23 ++ -- --SSGA-24 -- -- ++SSGA-25 0 0 +SSGA-26 - 0 +SSGA-27 -- 0 +SSGA-28 0 0 +SSGA-29 -- 0 +SSGA-30 -- 0 ++SSGA-31 0 ++SSGA-32 0 +SSGA-33 + ++SSGA-34 - ++SSGA-35 0 ++ ++SSGA-36 + ++ + ++SSGA-37 + -SSGA-38 0 +SSGA-39 -SSGA-40 +SSGA-41 +SSGA-42 +SSGA-43 +SSGA-44 +SSGA-45 +SSGA-46 +SSGA-47 +SSGA-48 +SSGA-49 +SSGA-50 +SSGA-51 +SSGA-52 +SSGA-53 +SSGA-54 +SSGA-55 0__________________________________________________________________________ Test Num. 1 MXinduced fibrosarcoma, in vitro cell aggregation assay; 2 3LL (Lewis) carcinoma, in vitro cell aggregation assay; 3 B16 melanoma, in vitro cell aggregation assay; 4 F10 B16 melanoma metastatic cell line, in vitro cell aggregation assay; 5 MXinduced fibrosarcoma, in vivo experimental metastasis assay; 6 3LL (Lewis) carcinoma, in vivo experimental metastasis assay; 7 B16 melanoma, in vivo experimental metastasis assay; 8 MDAMB-435 human breast carcinoma metastatic cell line, in vitro colony formation in agarose assay; 9 TXM13 human melanoma metastatic cell line, in vitro colony formation in agarose assay; Result + Inhibition ++ Strong Inhibition (>50%) - Stimulation -- Strong Stimulation (>50%) 0 No effect
The results of the various assays are summarized in Table III. It should be noted that, with the exception of SSGA-55 which was only examined in one test, all of the compounds either promote or inhibit cell adhesion in at least one test. These data suggest that the class of compounds described in the present invention are all affectors of cell adhesion. Some compounds, such as SSGA-12, SSGA-13, SSGA-36 and SSGA-19 inhibit cell aggregation in every test in which they were examined suggesting that these compounds are "universal" inhibitors. Other compounds exhibit different effects depending on the cell type and assay suggesting that these compounds are cell type specific in their inhibition or promotion of cell adhesion.
Naturally Occurring Glycoamines
It should be noted that larger glycoamines that include an amino acid linked to a sugar by one of the above-described links have been isolated from the blood stream of patients with various cancers. These compounds have been investigated as physiological components of human and rodent blood serum that merit interest as potential tumor makers. The level of these substances is substantially increased in blood serum from humans and animals with different forms of malignant solid tumors and leukemias. Structurally the glycoamines detected in blood represent carbohydrate-amino acid conjugates containing from 5 to 29 amino acids and from 1 to 17 carbohydrate residues. The chemical structure of glycoamines reveal mono-, di- and trisaccharides bound to the amino acids and assembled into higher molecular weight compounds via the formation of ester, Schiff base and Amadori product-type bonds with the involvement of the amino groups of amino acids and hydroxyl, aldehyde or keto groups of the carbohydrates. The function of these naturally occurring glycoamines has yet to be determined.
While large glycoamines have been detected in nature, the much simpler compounds of the present invention have not been detected in blood. If the compounds of the present invention exist in blood, they are presumably at concentrations below the detection threshold which is approximately 1 μMolar.
Various modifications to the present invention will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Accordingly, the present invention is to be limited solely by the scope of the following claims. | A class of molecules that alter cell adhesion. A cell adhesion affector according to the present invention essentially consists of an amino acid linked to a carbohydrate wherein the amino acid and the carbohydrate are linked to form a compound chosen from the group consisting of Schiff bases, N-glycosides, esters, and Amadori products. The carbohydrate is preferably a monosaccharide or a small oligosaccharide. The carbohydrate and amino acid sub-units may be chemically modified. For example, the amino acid may be modified by covalently bonding other groups to the amino group, carboxyl group, or side chain group of the amino acid. The carbohydrate sub-unit is preferably a pentose such as arabinose, xylose, ribose, ribulose, a hexose such as fructose, deoxyfructose, galactose, glucose, mannose, tagatose, rhamnose, or a disaccharade based on two of the above such as maltose, lactose, maltulose, or lactulose. | 2 |
This application is a division of application Ser. No. 08/622,961, filed Mar. 27, 1996, now U.S. Pat. No. 5,630,519.
This invention relates in general to an improved plastic knuckle pin for a coupler on a railway car and a method of making an improved plastic knuckle pin, and more particularly to a plastic knuckle pin characterized by a substantially uniform material matrix and a method of making the pin which substantially increases uniformity in the material by increasing the surface cooling area of the material, thereby decreasing air and moisture pockets in the material during the molding process.
BACKGROUND OF THE INVENTION
Heretofore, it has been known to use plastic knuckle pins in couplers on railway cars, as disclosed in U.S. Pat. No. 5,145,076, the disclosure of which is incorporated by reference. The known plastic knuckle pins of the type shown in the patent are made from a self-lubricating plastic material exhibiting sufficient flexibility to absorb substantial bending stresses without breaking, thereby enhancing the life of the pins. While it is suggested in the above patent that the plastic knuckle pin may be hollow or made in more than one piece, it is disclosed to be preferably molded as a unitary solid piece. Plastic knuckle pins have been proven superior over steel knuckle pins because the plastic knuckle pin absorbs substantial bending stresses without breaking and therefore enjoys a longer life. Moreover, plastic knuckle pins are substantially lighter in weight and therefore easier to handle.
However, it has been found that the injection molding process used to form the known solid plastic knuckle pin creates some, if not a multitude of, liberties or trapped air pockets in the plastic pin. Further, if the solid plastic pin is made during humid weather, the plastic material tends to absorb moisture from the air during molding. Both of these phenomena result in a plastic knuckle pin having less than an optimal material matrix uniformity. It is therefore desirable to produce a solid plastic knuckle pin characterized by a substantially higher material matrix uniformity than the current known solid plastic knuckle pins.
SUMMARY OF THE INVENTION
The present invention provides an improved plastic knuckle pin for couplers on railway cars and a method of making the improved plastic knuckle pin characterized by a substantially uniform material matrix. More particularly, the plastic knuckle pin of the present invention includes a shaft or body, a head at one end of the shaft, spaced-apart annular relief areas on the shaft, and self-locking legs at the end of the shaft opposite the head. A series or plurality of holes or slots extend along opposite sides of the shaft in a symmetrical pattern. The placement or molding of these holes or slots, referred to generally as fluting, evenly increases the cooling surface area of the material and prevents the build-up of trapped air and moisture in the plastic material during the molding or forming process, thereby dramatically improving the overall uniformity of the plastic material and creating a more reliable plastic knuckle pin. Moreover, the fluting in the shaft also adds to relieve stress in the shaft when bending forces are exerted on the pin by the coupler.
The method of the present invention generally includes the steps of melting a suitable plastic material in a conventional manner to a temperature of approximately 450 degrees fahrenheit (232° C.), injecting or pouring the melted plastic material into a mold or tool maintained at a temperature of approximately 180 degrees fahrenheit (82° C.), molding or forming the plastic knuckle pin with fluting from the plastic material in the tool or mold for approximately two minutes, removing the knuckle pin from the tool or mold, placing the knuckle pin in a hot water bath maintained at a temperature of approximately 180 degrees fahrenheit for approximately 20 minutes, removing the knuckle pin from the hot water bath; and then allowing the knuckle pin to cool in air for approximately ten minutes. The cooling process is greatly enhanced by the fluting in the knuckle pin which increases the cooling surface area of the material, thereby better allowing trapped air and moisture to escape the plastic material and resulting in a more uniform and reliable plastic knuckle pin than previously known.
It is therefore an object of the present invention to provide an improved plastic knuckle pin for couplers on railway cars.
A further object of the present invention is to provide an improved plastic knuckle pin characterized by a substantially uniform material matrix.
A further object of the present invention is to provide an improved plastic knuckle pin having fluting in the shaft which relieves stress in the shaft when bending forces are exerted on the pin by the coupler.
A further object of the present invention is to provide an improved method of making a plastic knuckle pin.
A further object of the present invention is to provide a method of making a plastic knuckle pin having a fluted shaft which increases the cooling surface area of the material, thereby allowing trapped air and moisture to escape the plastic material, resulting in a more uniform and reliable plastic knuckle pin than previously known.
Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of the improved plastic knuckle pin of the present invention;
FIG. 2 is a side elevational view of the plastic knuckle pin;
FIG. 3 is a top plan view of the plastic knuckle pin;
FIG. 4 is a cross-sectional view of the plastic knuckle pin taken substantially along line 4--4 of FIG. 1;
FIG. 5 is a bottom plan view of the plastic knuckle pin; and
FIG. 6 is a generally schematic view depicting the improved method of making the plastic knuckle pin of the present invention.
DESCRIPTION OF THE INVENTION
Knuckle pins are generally used in couplers for coupling two vehicles such as railway cars. The knuckle pin serves to pivotally interconnect the knuckle to the coupler body. A more detailed description and illustrations of a railway car coupler as well as the operation of a knuckle pin appear in U.S. Pat. No. 5,145,076.
Referring now to the drawings, and particularly to FIGS. 1 to 5, the knuckle pin of the present invention, generally indicated by numeral 10, includes a body or shaft 12, a head 14 at one end of the shaft 12, and self-locking coacting legs 16 and 18 at the end of the shaft 12 opposite the head 14. The plastic knuckle pin of the present invention is preferably a solid piece of molded urethane or polyurethane, as further described below. The urethane material provides the desired flexibility to enable the pin to absorb significant bending forces placed on the pin by the coupler without fatigue, thereby substantially reducing pin failure. It will be appreciated that other suitable plastic materials could be used as suggested by U.S. Pat. No. 5,145,076.
The head 14 of the pin 10 includes a somewhat dome-shaped upper end 20 which is sized diametrically larger than a pin opening in a coupler. The upper end 20 is also diametrically larger than the shaft 12 to define an annular shoulder 22. For reinforcement purposes, an annular radius (not shown) may be formed between the head 14 and the shaft 12 to guard against head damage from mallet blows during installation and to avoid sharp corners in the pin 10.
At the end of the shaft opposite the head, two self-locking legs 16 and 18 coact to lock the pin 10 in the coupler. The self-locking legs 16 and 18 are compressed together or toward each other as the pin is driven into the pin opening in the coupler and expand or snap apart when the pin is fully inserted in the coupler. In a conventional manner, the pin is prohibited from being removed because the outer ends of the legs are radially larger than the pin opening. Alternatively, a cotter pin hole and cotter pin may be used to lock the pin in place. Other suitable locking devices could also be used.
The shaft or body 12 is generally cylindrical in shape and preferably includes upper and lower relief areas 26 and 28 having an outer diameter smaller than the shaft for relieving stress. The shaft 12 also has a series or plurality of holes or slots 30 symmetrically positioned along opposite sides of the shaft. The holes or slots 30, referred to as longitudinal fluting in the shaft, are round or oval, although the holes or slots may be formed in other shapes. Preferably, there are four pairs of oval slots 32a, 32b, 32c, and 32d positioned along each side of the shaft and three pairs of round slots 34a, 34b, and 34c positioned along each side of the shaft. More specifically, on opposite sides of the shaft two pairs of oval slots 32a are positioned in the shaft between the head 14 and the upper relief area 26, two pairs of round slots 34a are centrally positioned in the upper relief area 26, six pairs of oval slots 32b, 32c, and 32d are positioned in the shaft between the upper and lower relief areas 26 and 28, two pairs of round slots 34b are centrally positioned on the shaft in the lower relief area 28, and two pairs of round slots 34c are positioned in the shaft between the lower relief area 28 and the self-locking legs 16 and 18.
The placement of the slots or fluting in the shaft increase the cooling surface area of the plastic material during the molding process, thereby allowing air and moisture to escape the material during the molding process. Furthermore, the slots or fluting in the shaft relieves stress in the shaft in use when bending forces are exerted on the pin by the coupler. The fluting allows the material to work or bend more without breaking. In particular, there are greater compression paths provided by the slots, especially in the upper and lower relief areas. Two related advantages provided by the improved knuckle pin of the present invention are that less material is needed to make the pin, resulting in material cost savings and resulting in a lighter weight pin.
Referring now to FIG. 6, the improved method of molding the plastic knuckle pin of the present invention is schematically illustrated. The plastic knuckle pin is preferably made from urethane, black in color, and more specifically, an unfilled polyurethane. According to the method of the present invention, the unfilled urethane or other plastic raw material 50 is first melted in a tank or reservoir 52 at a temperature of approximately 450 degrees fahrenheit (232° C.) in a conventional manner. The molten plastic material 50 is then injected or poured into a mold or tool 54 maintained at a temperature of approximately 180 degrees fahrenheit (82° C.). The tool 54 is maintained at the appropriate temperature by circulating fluid (not shown) in the mold. Other methods could be used to maintain the tool at the appropriate temperature. The plastic material 50 is maintained in the mold 54 for approximately two minutes to reduce the temperature and allow the plastic to sufficiently harden so it can be removed from the mold. The plastic knuckle pin 10 is thus formed with fluting or slots 30 along opposite sides of the shaft 12.
The knuckle pin 10, which comes out of the mold at approximately 200 degrees fahrenheit (93° C.), is then removed from the mold 54 and placed or dropped in a hot water bath 56 maintained at a temperature of approximately 180 degrees fahrenheit (82° C.). The pin is allowed to cool in the hot water bath 54 for approximately 20 minutes. This cooling period relieves any stresses that may build up during the molding process. The pin 10 is then removed from the hot water bath and placed on a cooling surface 58 where the pin is allowed to cool in air for approximately ten minutes.
The slots or fluting in the shaft of the pin 10 improves the material flow in the mold cavity and provides a significantly greater cooling surface area for the pin which greatly enhances the cooling process. Further, the fluting allows air and moisture to escape the material as it cools, and enhances injection of the material into the mold. The improved method of the present invention unexpectedly provides a more uniform and reliable plastic knuckle pin than previously known which is easier to mold. Approximately thirty shots an hour can be made with the appropriate method in a single mold.
It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims. | An improved plastic knuckle pin for a coupler on a railway car and a method of making the improved plastic knuckle pin whereby the improved plastic knuckle pin has a substantially uniform material matrix and the method of making the pin increases uniformity in the material by increasing the surface cooling area which decreases air and moisture pockets in the material during the molding process. | 8 |
BACKGROUND OF THE INVENTION
The invention relates to internal combustion engines and particularly to a system for supplying oil to the crankcase of an internal combustion engine.
Known internal combustion engines utilize some form of an oil pump for supplying oil to the crankcase and cylinders of the engine. If a steady flow of oil is not supplied to the moving parts in the engine, severe and possibly permanent damage may result. Commonly known oil pumps employ some form of a solenoid that includes an inductive solenoid winding and an armature moveable within the winding in response to current flow through the winding. If the armature becomes lodged or stuck in a particular position (as sometimes happens with mechanical devices), then the supply of oil to the engine may cease.
SUMMARY OF THE INVENTION
Accordingly, the invention provides an internal combustion engine and an oil supply failure detection circuit for determining whether the supply of oil to the internal combustion engine has been interrupted. The engine includes a solenoid oil pump for supplying oil to the engine. The oil pump has an armature and a solenoid winding encircling the armature so that, as current flows through the solenoid winding, the magnetic field generated by the current causes longitudinal movement of the armature in response to the current.
The engine also includes an electronic control unit ("ECU") for generating control signals that selectively cause the current to flow through the solenoid winding. The ECU includes means for detecting movement of the armature. In one form, the means for detecting movement of the armature is a current measuring device connected to the solenoid winding to determine the amount of current flowing through the winding. The ECU monitors the measured current and compares the measured current with a current flow profile stored in the ECU memory. Based upon this comparison, the ECU determines whether or not the solenoid pump is operating normally.
If the armature is stuck, so that the pump is not operating properly, the ECU can attempt to free the armature, so that the pump operates properly, either by increasing the voltage applied to the solenoid or by increasing the frequency with which the solenoid is energized.
More particularly, the invention provides apparatus comprising: a solenoid including an armature and a solenoid winding encircling the armature for causing movement of the armature in response to current flow through the solenoid winding; and an electronic control unit including a sensor for detecting the movement of the armature.
The invention also provides apparatus comprising: an electronic control unit for generating control signals; and a solenoid including an armature and a solenoid winding encircling the armature and being connected to the electronic control unit so that the electronic control unit causes movement of the armature and so as to allow the electronic control unit to detect movement of the armature.
The invention also provides an engine assembly comprising an internal combustion engine, an electronic control unit for generating control signals for controlling the engine and including a sensing resistor, a controller having an analog to digital converter connected to the sensing resistor and having an output port, and a transistor having a base connected to the output port, an emitter connected to the sensing resistor and a collector, a solenoid oil pump for supplying oil to the engine and including an armature, and a solenoid winding encircling the armature and being connected to the collector so that the electronic control unit causes current flow in the solenoid winding to move the armature and so that the electronic control unit detects the flow of current in the solenoid winding in order to determine whether the armature is in a stuck condition, and freeing means for freeing the armature from the stuck condition.
Other features and advantages of the invention are set forth in the following detailed description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of an internal combustion engine embodying the invention.
FIG. 2 is a schematic illustration of the fuel pump and the oil supply failure detection circuit of the internal combustion engine.
FIG. 3 is a graph of the solenoid pump current waveform under normal operating conditions.
FIG. 4 is a graph of the solenoid current waveform when the solenoid armature is stuck.
Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways, Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting,
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Partially shown in FIG. 1 of the drawings is an internal combustion engine 10. One cylinder 14 of the engine 10 is illustrated in FIG. 1. The engine 10 includes a crankcase 18 defining a crankcase chamber 22 and having a crankshaft 26 rotatable therein. An engine block 30 defines the cylinder 14. The engine block 30 also defines an intake port 34 communicating between the cylinder 14 and the crankcase chamber 22 via a transfer passage 38. The engine block 30 also defines an exhaust port 42. A piston 46 is reciprocally moveable in the cylinder 14 and is drivingly connected to the crankshaft 26 by a crank pin 50. A cylinder head 54 closes the upper end of the cylinder 14 so as to define a combustion chamber 58. The engine 10 also includes a fuel injector 62 mounted on the cylinder head 54 for injecting fuel into the combustion chamber 58. A spark plug 66 is mounted on the cylinder head 54 and extends into the combustion chamber 58.
The engine 10 also includes an oil pump 70 (shown schematically in FIGS. 1 and 2) and an oil reservoir 74 (FIG. 1 only) connected to the oil pump 70. The oil pump 70 draws oil from the oil reservoir 74 and pumps the oil into the crankcase chamber 22 to lubricate the moving parts of the engine 10. As shown in FIG. 2, the oil pump 70 is connected to a source of electrical current (+V) and includes a housing 76, a ferromagnetic armature 78, and a solenoid winding 82 which is supported by the housing 76 and which encircles the armature 78 so that flow of electrical current through the solenoid winding 82 causes movement of the armature 78 to pump oil from the oil reservoir 74 to the crankcase chamber 22. Because the armature 78 is ferromagnetic, the position of the armature 78 relative to the solenoid winding 82 affects the inductance of the solenoid winding 82 and the flow of current therethrough. Movement of the armature 78 causes movement of a valve member 84 (shown schematically in FIG. 2) which corresponds to the valve member 251 of the application identified below.
While the invention is applicable to any oil pump, the preferred oil pump is shown and described in the co-pending U.S. patent application Ser. No. 08/507,051, which is titled "OIL LUBRICATING SYSTEM FOR A TWO-STROKE INTERNAL COMBUSTION ENGINE", which is filed on even date herewith and which is incorporated herein by reference.
Referring to FIG. 2, the internal combustion engine 10 also includes an ECU 86 for controlling the operation of the engine 10. The ECU 86 includes a transistor 90 which operates in the active region to control the flow of current through the solenoid winding 82. The transistor 90 includes a collector 94 connected to the solenoid winding 82, a base 98 and an emitter 102. The ECU 86 also includes a sensing resistor 106 connected between the emitter 102 and a ground or reference point. The ECU 86 also includes a controller 110 having an analog to digital converter ("ADC") 114 connected to the emitter 102 of the transistor 90. The controller 110 also includes an output port 118 connected to the base 98 of transistor 90.
In normal operation, current flowing through the solenoid winding 82 and transistor 90 causes movement of the armature 78 of the oil pump 70. Movement of the armature 78 results in a continuous change in the inductance of the winding and a corresponding smooth exponential increase in the flow of current through the winding 82. As current flows through the winding 82, a voltage develops across sensing resistor 106. FIG. 3 illustrates the current waveform for normal operation of the oil pump 70. The voltage on the sensing resistor 106 is input to the ADC 114 of the controller 110. When the armature 78 reaches the end of the pump stroke, the inductance of solenoid winding 82 quickly ceases to change resulting in a small step or jump in the current waveform. This step is identified by reference numeral 140 in FIG. 3.
FIG. 4 illustrates waveform indicative of the solenoid winding current for an oil pump with an armature that is stuck. If the solenoid armature 78 is stuck, then the inductance of the winding 82 does not change and the current rises exponentially in the winding 82. Because the inductance is constant and the armature is fixed, there is no change to detect in the rate of change of the inductance in the winding 82 and no resulting step in the waveform indicating the solenoid winding current. By measuring the voltage on the sensing resistor 106 at two (at least) different periods in time, the controller 110 can determine whether or not there is a step in the solenoid current waveform and thereby detect whether the oil pump is operating normally. This is achieved using a software based program that scans the voltage on the sensing resistor 106 at predetermined intervals. If the step 140 is detected, then the solenoid is operating normally and no action is necessary except to reset the circuit for the next pumping stroke. If the step is not detected, then a counter (not shown) is incremented. The counter may be connected to an indicator to provide an signal to the operator of the boat that a problem exists with the oil pump.
In other words, the ECU 86 utilizes a current feedback loop to monitor the magnitude of the current flowing in the solenoid winding 82 and determine, based on the magnitude of the current flow through the solenoid winding 82, whether or not the oil pump 70 is operating correctly. In other embodiments (not shown), other circuit parameters may be used such as current slope, change in inductance, etc.
The engine 10 preferably further comprises means for freeing the armature 78 when the armature is stuck. Various suitable means can be employed. In the preferred embodiment, the ECU 86 can either: (1) increase the frequency of the signal with which the transistor 90 is biased to cause current flow through the winding 82; or (2) increase the voltage (normally 12 volts) applied to the winding 82. Preferably, the engine 10 includes a dual voltage alternator such as that disclosed in co-pending U.S. patent application Ser. No. 08/507,028, which is titled "DUAL VOLTAGE REGULATED SUPPLY CIRCUIT FOR A MARINE PROPULSION DEVICE", which is filed on even date herewith and which is incorporated herein by reference. The engine 10 accordingly has a 12-volt output and a 24-volt output (see FIG. 2). As shown in FIG. 2, the ECU 86 includes a switch 150 operated to connect the solenoid winding 82 to either the 12-volt output or the 24-volt output. Additionally, the ECU 86 could increase the frequency of energization and increase the voltage at the same time.
Various features and advantages of the invention are set forth in the following claims. | An internal combustion engine assembly including an internal combustion engine, an electronic control unit for generating control signals for controlling the engine and a solenoid oil pump for supplying oil to the engine. The oil pump includes an armature and a solenoid winding encircling the armature and being connected to the electronic control unit so that the electronic control unit causes movement of the armature and so as to allow the electronic control unit to detect the flow of current in the solenoid winding. | 5 |
This application is a continuation application of application Ser. No. 08/341,163, filed Nov. 18, 1994, which application is a continuation application of application Ser. No. 07/984,833, filed Dec. 3, 1992 (now abandoned).
BACKGROUND OF THE INVENTION
The present invention relates to a process and to a device for manufacturing synthetic gas, which may be used for producing for example: ammonia, methanol, urea, hydrocarbons, etc.
The gases obtained in accordance with the invention may be converted and then possibly purified or be used as reducing gases.
Synthetic gas is conventionally obtained through the reaction of a mixture of hydrocarbons or fuel with an oxidant.
A first way to produce synthetic gas consists of associating a primary reforming with a secondary reforming. The primary reforming reactor is conventionally made up of tubes filled with a catalyst and heated either through external combustion, or through heat exchange with warm effluents, for example with those of the secondary reforming reactor. The hydrocarbon is generally introduced into the primary reforming reactor with high steam excess.
The effluents resulting from the primary reforming are then introduced into the secondary reformer, which is also supplied with oxidant.
U.S. Pat. No. 3,278,452 describes a secondary reformer whose improvement consists in an additional introduction of oxidant between catalytic beds arranged successively in the reactor. However, the improvement provided by the stepped lay-out of the oxidant does not solve the main drawback of this type of reactors which requires a high amount of steam whose production is costly. Moreover, the drawback of steam excess is to change the distribution between the hydrogen, the carbon dioxide and the carbon monoxide present in the synthetic gas.
Another way to manufacture synthetic gas, with a low steam consumption, consists of achieving partial oxidation of the hydrocarbons.
U.S. Pat. No. 4,699,631 shows such an example of a reactor working without a catalyst, by means of a flame. However, this type of reactor always produces a certain amount of soot due to combustion under lack of oxygen, when afterwards requires a costly scrubbing. Besides, if the amount of soot is to be decreased, the oxygen consumption has to be increased, which reduces the reactor efficiency. Thus, although working with little steam, the drawback of this type of reactor is to produce soots when the oxygen consumption is decreased or when working in air.
Besides, the applicant has protected, by means of patent application EN.91/09,214, a reactor of the type defined at the beginning of the description and comprising a chamber referred to as "short residence time chamber", that is to say such that V<0.4 D/P; V being the inner volume of the chamber; D being the overall weight flow entering the combustion chamber; P being the pressure prevailing inside the chamber. The object of such a reactor is to reduce steam and cost requirements.
However, for reactors whose combustion chamber volume is too small, the fuel and oxidizer jets might lead to an erosion of the surfaces towards which they are projected, after several thousand hours of operation.
SUMMARY OF THE INVENTION
The object of the invention is to propose a synthetic gas reactor whose combustion chamber volume is sufficient to avoid this type of erosion.
Besides, in order to have a reactor requiring little steam, it appeared necessary, when the volume of the combustion chamber is relatively large, to introduce successively additional fuel and then oxidizer into the catalytic bad located downstream from the combustion chamber.
The invention thus relates to a reactor for manufacturing synthetic gas and comprising within a single housing:
a non catalytic combustion chamber comprising at least one fuel injection element and at least one oxidizer injection element so as to achieve a partial combustion in said chamber, and
at least one catalytic bed into which the gases coming from the combustion chamber run, and further comprising successively, in the direction of flow of the gases, at least one additional fuel injection element and at least one oxidizer injection element.
More particularly, the combustion chamber is such that:
V>0.4 D/P
V being the inner volume of said chamber expressed in cubic meter,
D being the overall weight flow entering the chamber, expressed in kg/s, and
P being the pressure prevailing inside the chamber, expressed in megapascals.
Preferably, the fuel introduced into the combustion chamber and into the catalytic bed mainly consists of hydrocarbons which may be admixed with carbon oxides and/or hydrogen.
The oxidizer may be pure oxygen, or oxygen admixed with nitrogen, steam, carbon dioxide. The oxidizer may also be a mixture of oxygen and of another inert gas.
Preferably, the overall oxidizer supply, defined as the number of moles of oxygen contained in the oxidizer injected into the reactor in relation to the number of moles of carbon contained in the injected fuel, ranges between 0.3 and 0.65, and the same supply relative to the introduction of oxidizer in said combustion chamber ranges between 0.45 and 0.75.
Advantageously, the hydrogen/hydrocarbons ratio, defined as the molar ratio expressed in number of moles of hydrogen in relation to the number of moles of carbon of the fuel introduced into the combustion chamber, is less than 1.
Besides, steam may be introduced with the oxidizer and/or the fuel. The steam supply in the reactor, defined as the number of moles of water in relation to the number of moles of carbon, is less than 1.5.
The fuel may be preheated, before entering the combustion chamber, between 100° and 850° C., preferably between 600° and 700° C. The oxidant may be preheated at each inflow between 100° and 900° C., preferably between 135° and 750° C. The upper limit of this range (750° C.) may be lowered to 600° C., notably in cases where the oxidant is oxygen or mainly pure oxygen.
The invention further relates to the process for manufacturing synthetic gas, which consists of performing within a single reactor:
partial conversion of a fuel in a non catalytic combustion chamber working under lack of oxidant; the fuel being introduced apart from the oxidant into said chamber, and
additional oxidant supply at the level of a catalytic bed located downstream from said combustion chamber.
In particular, the process further consists of introducing fuel at the level of said catalytic bed upstream from the additional oxidant, and the inner volume V of said chamber is such that V>0.4 D/P
D being the overall weight flow entering the combustion chamber, expressed in kg/s,
P being the pressure prevailing inside the chamber, expressed in megapascals, and
V being expressed in cubic meter.
The invention also relates to the application of the process and/or of the device to the production of methanol, ammonia, hydrocarbons, urea, acetic acid, hydrogen or a reducing gas.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the invention will be clear from reading the following description given by way of non limitative example, with reference to the accompanying drawings in which:
FIG. 1 is a simplified longitudinal section of a vertical type reactor according to the invention,
FIG. 2 is a simplified longitudinal section of a transverse type reactor according to the invention,
FIG. 3 is a diagram of an embodiment example of the invention.
The same references will be used for the elements common to the various embodiments of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Thus, in accordance with these figures, the reactor is mainly made up of a combustion chamber 1 provided with at least two distinct inlets, one 2 allowing the fuel to be introduced, the other 3 injecting the oxidizer which is an oxidant.
Injection elements 2 and 3 do not only allow the fuel and the oxidizer to be introduced into said chamber 1, but also the combustion to be stabilized therein.
A partial combustion takes place in combustion chamber 1 and the effluents from this combustion run directly into the second part 4 of the reactor, which is filled with at least one catalytic bed.
The second part 4 of the reactor, also called catalyst or catalytic bed in the description hereafter, is part of the reactor since it shares a common surface 5 with combustion chamber 1. This surface is not necessarily horizontal.
Besides, catalytic bed 4 is provided with at least one inlet 6 for the additional oxidant and with at least one inlet 7 for the additional fuel. FIG. 1 shows two injectors 6 and two injectors 7, which constitutes a particular embodiment of the invention.
The first fuel injector 7 is advantageously located upstream from the first oxidizer injector 6, in relation to the direction of propagation of the gases in the reactor.
Finally, one or several outlets 8, located at the end of catalytic bed 4 in relation to the direction of flow of the gases in the reactor, are of course provided.
Injectors of any type known per se may be used to introduce the various components stated above.
The broad lines of the reactor according to the invention being given, it is now necessary to specify certain working conditions.
Combustion chamber 1 must make it possible to work with a sufficient residence time and under lack of oxidant.
One way to define the "sufficient" residence time may consist of imposing the following inequation:
V>0.4 D/P
V being the volume of chamber 1 expressed in cubic meter,
D being the overall weight flow entering chamber 1, expressed in kg/s, and
P being the predetermined operating pressure prevailing in chamber 1, expressed in megapascals.
As it is well-known by the man skilled in the art, and without the following description being considered as limitative, the catalysts used in accordance with the present invention are made up of:
a support based on oxides, having refractory properties and whose acidity has been neutralized,
an active phase comprising 2 to 40%, preferably 3 to 30% by mass of at least one reducible metal M selected from nickel, cobalt, chromium, platinum metals. Taken separately, the proportion of platinum metals, if there are any, ranges between 0.01 and 1% by mass of the total above.
The support based on oxides comprises at least one simple or mixed oxide from the following list: alpha alumina; aluminate of spinel structure NA1 2 O 4 - xA1 2 O 3 with x=0, 1, 2; at least one metal N selected from the list: magnesium, calcium, trontium, barium, potassium; aluminate of magnetoplumbite (or hexaaluminate) structure NA1 12 O 19 ; N being a metal from the list above.
Besides, these supports may be possibly promoted by at least one metal P selected from silicium, potassium, uranium.
In the most severe thermal conditions, for example with mean temperatures higher than 1000° C., preferably higher than 1100° C. and most preferably higher than 1200° C., it may be advantageous to arrange at the top an attack layer consisting for example of chromium oxide or of a low proportion of nickel deposited on one of the supports cited above. This catalyst will protect the other catalyst located in the lower layer as described hereafter.
The catalysts used in the process according to the invention are prepared either by impregnation of the preformed support by a solution containing at least one metal M and possibly at least one metal P, drying and thermal activation; or by mixing of the precursors oxides of metal aluminum, M and N, possibly P, forming, drying and activation. Metal P, if used, may be added either before or after the forming stage.
They may finally also be prepared by coprecipitation or by the sol-gel process.
The catalysts used in the process according to the invention may exhibit the most varied geometries: pellets, balls, extrudates, annular pellets, ribbed rings, wheel-shaped catalysts from 3 to 30 mm. They may even be used in the form of monoliths, consisting either of the oxides and/or the metals corresponding to the metallic elements cited above, or of refractory steel monoliths coated with said elements. One or several monoliths may be present.
It goes without saying that, according to operating conditions, the charge used, the local composition, the presence or not of steam, the level of the risk of carbon deposition, such or such formula will be used. Thus, the catalysts promoted by potassium or strontium, or by potassium plus calcium, or else calcium will be preferably used when the risk of carbon deposition is the highest.
The present invention is preferably performed in the presence of at least one catalyst allowing the selective activation of the wanted reaction processes to be achieved, that is to:
1) selectively convert the methane and, if they are also present, the higher hydrocarbons, by direct or indirect reaction with the oxygen and/or the steam present, to carbon oxides and hydrogen,
2) activate the other reaction processes wanted and notably the conversion of the coke precursors, according to the reaction:
CH.sub.x +H.sub.2 O⃡CO+H.sub.(2+x) ×≧0
3) allow disproportionation reactions of CO to be limited
2 CO⃡CO.sub.2 +C
through the removal of the carbon formed, as above,
4) if CO 2 is at least partly recycled, selectively activate the reaction:
CH4+CO.sub.2 ⃡2CO+2H2
The catalysts known by the man skilled in the art and used equally in steam reforming, secondary reforming, partial catalytic oxidation processes are suitable on several accounts for the embodiment of the invention. It is however preferable that the catalysts used have a good thermal stability (for example up to at least 900° C. and preferably at least 1000° C.).
Besides, these catalysts may be arranged in one or several beds, laid out as described above and separated by one or several devices (6, 7) for injecting one or several gaseous compounds such as those described above.
The volumetric velocity per hour (VVH) with respect to hydrocarbon and expressed in NTP volumes of hydrocarbon per hour and per volume of catalyst may be expressed in corrected VVH. If m is the average number of atoms of carbon in the charge, the corrected VVH (which will be that used in the process of the invention) is:
corrected VVH=VVH×m.
A corrected VVH ranging between 200 and 10,000 h -1 , preferably between 400 and 8000, and most preferably between 500 and 7000 h -1 , is used.
It is obvious to the man skilled in the art that the catalyst bed can be parted in n bed of volumes V 1 , V 2 , . . . V i . . . V n , such that V 1 +V 2 +. . . +V i +. . . +V n =v, the VVH remaining expressed in relation to the overall catalyst volume v.
The fuel introduced through the inlet or inlets 2 of the combution chamber and through inlets 7 will preferably consist of hydrocarbons (natural gas or methane for example) admixed with carbon oxide (CO, CO 2 ) and/or with hydrogen and/or with inert gases.
Steam may also be admixed with the hydrocarbons, preferably in the proportion defined at the beginning of the description.
The proportion of hydrogen in the hydrocarbons is such that the H 2 /hydrocarbons ratio is less than 1.
The composition of the gases injected at the various inlets is not necessarily identical.
The oxidant introduced at the level of inlet 3 may be pure oxygen, a mixture of oxygen and nitrogen, air, a mixture of oxygen and steam, a mixture of oxygen and carbon dioxide, a mixture of oxygen and of another inert gas.
The overall supply of steam and of carbon dioxide remains low in relation to certain other technologies of the prior art cited above. In fact, a molar ratio ##EQU1## will be preferably used, where C is the total carbon comprised in the hydrocarbons, and where (H 2 O+CO 2 ) is the sum of the molar flow rates of water and CO 2 injected. By way of comparison, the same molar ratio for a conventional autothermic reactor would be higher than 2.
Having several oxidant inlets according to the invention allows the composition of the fuel and of the oxidant to be modulated at the various stages, and thus the reaction to be better controlled. For example, for the synthesis of ammonia, if the stoichiometry N 2 +3H 2 is wanted, air will be introduced at the level of the catalytic bed through the inlet or the other inlets 6.
Preheating is recommended, both for the fuel and for the oxidant, before their introduction into the reactor. The fuel may be preferably preheated between 100° C. and 850° C., and the oxidant may be preheated between 100° C. and 900° C. More precisely, temperatures ranging between 200° C. and 750° C. are preferable.
The pressure in combustion chamber 1 ranges between 1 and 150 bars, preferably between 30 and 100 bars.
The significance of the present invention will be clear from comparing the examples hereafter. Example 1 gives results of the prior art, whereas examples 2 and 3 illustrate embodiments of the invention. In all the following examples, the reactor receives natural gas containing (by volume) 98.7% of methane, 0.9% of ethane and 0.4% of nitrogen.
EXAMPLE 1
It relates to a pilot reactor whose overall inner volume is 250 liters (chamber plus catalyst). This reactor is half filled with catalyst so as to leave a 125-liter free volume in the chamber.
The catalytic bed comprises at the top a first layer of a catalyst containing 3.8% of chromium on alpha alumina. This layer occupies 20% of the overall catalyst volume. The rest consists of a catalyst containing 8.8% of nickel also deposited on alpha alumina.
The combustion chamber is supplied with natural gas and oxygen, both admixed with steam and introduced at 777K. The natural gas contains 50% of its steam flow rate: the overall flow rate (steam plus natural gas) is about 150 Nm 3 /h. The pure oxygen, whose flow rate is 58 Nm 3 /h, is admixed with steam whose flow rate is 195 Nm 3 /h.
The pressure in the reactor is 30 bars.
The temperature on the first catalyst layer is 1453K.
It has been possible to bring the flow rate of natural gas from 100 up to 112 Nm 3 /h (with 50 Nm 3 /h of steam) and the flow rate of steam introduced with the oxygen from 195 Nm 3 /h down to 170 Nm 3 /h.
The temperature at the top of the bed is then 1476K.
The outlet composition is the following:
______________________________________ H.sub.2 42.8% CO.sub.2 7.2% CH.sub.4 0.6% CO 12.4% H.sub.2 O 37%______________________________________
With such a reactor, the steam flow cannot be decreased below 160 Nm 3 /h, regarding oxygen, without causing an increase in the pressure drop due to a load of soot in the catalyst.
EXAMPLE 2
The example above, according to the prior art, shows that it is not possible to reach a H 2 /CO ratio close to 2, which is a necessary condition for manufacturing higher hydrocarbons through processes of the Fisher-Tropsch type.
The reactor in accordance with this second example is identical to that of example 1, as well as the flow rates entering combustion chamber 1. Besides, the volumes of chamber 1 and of catalyst 4 remain unchanged.
However, four tubes 7 pierced with openings open into catalytic bed 4, at the two thirds of the height from outlet 8 onwards. These tubes are protected by a steam-cooled double jacket. In this part of the catalytic bed, the temperature is 1253K.
A mixture of 112 Nm 3 /h of natural gas and 22 Nm 3 /h of steam at 780K flows in through tubes 7. Cooling of the tubes through steam prevents coking in the tubes.
Besides, four tubes 6 pierced with openings open into bed 4, at half the height thereof. Contrarily to tubes 7 supplying natural gas, tubes 6 are made of alumina and are not cooled.
The catalytic bed at this level consists of a layer of catalyst with 3.8% of chromium.
A mixture of oxygen, steam and carbon dioxide, all preheated at 765K, flows in through tubes 6.
______________________________________ O.sub.2 flow 65 Nm.sup.3 /h Steam flow 24 Nm.sup.3 /h CO.sub.2 flow 62 Nm.sup.3 /h______________________________________
At the reactor outlet, the temperature is about 1245K; the composition of the gases is the following:
______________________________________ H.sub.2 41.9% CO.sub.2 8.8% CH.sub.4 0.8% CO 19.4% H.sub.2 O 29.1%.______________________________________
EXAMPLE 3
The reactor in accordance with example 2 may be modified so as to further decrease the necessary steam rate.
The reactor in accordance with example 3 is an embodiment of the invention exhibiting this feature. FIG. 3 illustrates this reactor.
Thus, the overall volume of the reactor is 250 l (0.25 m 3 ). The volume of combustion chamber 1 is 80 liters.
At the level of combustion chamber 1, gas is introduced at a flow rate of 75 Nm 3 /h and steam is introduced at a flow rate of 135 Nm 3 /h through inlet 2 intended for natural gas. The temperature of the mixture introduced is about 773K. A mixture of oxygen, at a flow rate of 45 Nm 3 /h, and of steam, at a flow rate of 135 Nm 3 /h, is introduced through inlet 2 intended for the oxidant, the mixture being brought to a mean temperature of 793K.
In catalyst 4, four introduction levels are provided:
At the level which is closest to combustion chamber 1, a mixture of natural gas (flow rate of about 85 Nm 3 /h) and of steam (flow rate of about 17 Nm 3 /h) is introduced at a temperature close to 773K. Four tubes 7 may be provided, at 90° in relation to one another, to inject this mixture.
Four other tubes open into a second level of the catalytic bed, all of them being located at the same distance from the first level. These tubes 6 allow a mixture of oxygen and of steam to be introduced at about 673K. The flow rate of oxygen is preferably 47 Nm 3 /h, and the flow rate of steam is close to 25 Nm 3 /h.
Preferably, tubes 6 located at this second level are angularly equidistant and, moreover, they are angularly offset with respect to the tubes 7 of the first level.
Besides, several (preferably four) tubes 7 intended to introduce a natural gas-steam mixture open into the third level of the catalytic bed. The flow rate of natural gas is about 95 Nm 3 /h, and the flow rate of steam is close to 19 Nm 3 /h. The mixture is introduced at about 773K.
Finally, the fourth level is more specifically reserved for the introduction of pure oxygen, at about 573K, with a flow rate of 55 Nm 3 /h. Four tubes are then preferably provided, which have the same features as the tubes at the other levels, that is that they are angularly equidistant and angularly offset with respect to the tubes of level 3.
Preferably, the various levels are equidistant, located each at a distance, measured on the longitudinal axis of the reactor, equal to one sixth of the overall height of catalytic bed 4.
Catalytic bed 4 consists of alternating layers made up respectively of 3.8% of chromium on alpha alumina and of 8.8% of nickel on alpha alumina, as illustrated in FIG. 3. Injection tubes 7 located at the first and third levels of the catalytic bed open preferably into the catalyst containing 8.8% of nickel, whereas tubes 6 located at the second and fourth levels open into the catalyst with 3.8% of chromium.
Preferably, the distance d measured on the longitudinal axis of the reactor, between the fourth level and the end of bed 4 towards outlet 8, is about one third of the overall height of the bed.
At the reactor outlet, in accordance with this example, the temperature of the gases is about 1351K, with the following composition:
______________________________________ H.sub.2 53.6% H.sub.2 O 18.5% CH.sub.4 0.6% CO 23.2% CO.sub.2 4.1%______________________________________
In this example, one should notice that the carbon dioxide content is higher than the specifications of a synthesis known as Fisher-Tropsch synthesis. A decarbonation process will allow this content to be reduced. The separated carbon dioxide may be advantageously introduced in place of part of the steam.
Other modifications or additions may of course be provided by the man skilled in the art to the reactors described above by way of example, without departing from the scope of the invention. | The present invention relates to a process and to a device for manufacturing synthetic gas.
The reactor in accordance with the invention comprises within a single housing:
a non catalytic combustion chamber (1) comprising at least one fuel injection element (2) and at least one oxidizer injection element (3) so as to achieve a partial combustion in said chamber referred to as "sufficient residence time chamber", and
at least one catalytic bed (4) into which the gases coming from combustion chamber (1) run, and further comprising at least one additional oxidizer injection element (6) and at least one fuel injection element (7).
The reactor and the process in accordance with the invention may be applied to any chemical manufacturing utilizing synthetic gas. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates to swimming pools, and more particularly to above-ground prefabricated swimming pools in which common components can be used to construct pools of different sizes.
In the design and construction of prefabricated above-ground pools, the cost of fabricating standard components is a major consideration. It is necessary to provide pools of a variety of sizes to accommodate the available space and the diverse desires of consumers, and the variety of components necessary for the construction of such pools is thus very large. Accordingly, the cost of manufacturing the prefabricated pool components is increased because production runs are shorter. Additionally, distributors and retailers of pools must carry large inventories, a problem which is particularly acute in areas where the sale of pools is highly seasonal.
According to known swimming pool constructions, a cylindrical wall is supported by vertical posts spaced about its periphery. A series of lip members are arranged end-to-end about the top of the wall and supported by the posts. It is conventional to attach the lip members to the posts with connecting hardware that fixes the angle formed by adjacent lip members. This angle is a function of the number of posts used in the pool. Thus each successive size of pool generally requires the prefabrication of different structural components such as lip members, posts and connecting hardware so that the number of posts can be increased. Alternatively, if the same number of posts is used as the pool size is increased, the strength of the posts must be increased with the pool size, and the length of the lip member must be varied.
SUMMARY OF THE INVENTION
The present invention is an above-ground prefabricated swimming pool construction that permits many common components to be used in pools of various sizes. The pool includes a conventional liner and wall. The wall is supported by posts that are spaced apart by a fixed predetermined distance regardless of the size of the pool. Thus pool size is increased by increasing the number of such posts arranged in a circle. Lip members of a predetermined length are arranged between the posts along the top edge of the wall. As pool size is increased, the number of lip members is increased along with the number of posts. The posts and lip members of different sized pools are interchangeable.
The ends of the lip members are connected to the top ends of the posts by brackets. Although the angle at which lip members are connected to the posts depends upon the size of the pool constructed, the brackets too are interchangeable between different sizes of pool because they permit adjustment of this angle.
According to an embodiment of the invention disclosed below, each lip member is joined at each end to a bracket by first and second fasteners. The first fastener permits only pivotal adjustment, while the second fastener permits both pivotal and sliding adjustment.
BRIEF DESCRIPTION OF THE INVENTION
For a complete description of the invention, reference may be had to the detailed description which follows and to the accompanying drawings wherein:
FIG. 1 is a three-dimensional pictorial view of a swimming pool constructed in accordance with the invention; and
FIG. 2 is an exploded three-dimensional view of a post and adjoining structure of the pool of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a prefabricated above-ground swimming pool 10 constructed in accordance with the present invention. The pool 10 includes a liner 12 formed by a flexible vinyl plastic sheet disposed within an upstanding cylindrical wall 14 erected in the conventional manner by bending a single flexible sheet (preferably of aluminum) and joining the ends in the conventional manner to form the perimeter of the pool. The hydraulic pressure of the pool is exerted radially outward against the aluminum wall 14.
A plurality of evenly spaced extruded preferably aluminum posts 16 support and position the wall 14. A plurality of elongated lip members 18 are disposed between successive posts 16 along the top edge of the wall 14. Each lip member 18 is wide enough to accommodate the curvature of the arc of the wall 14 that it subtends. The substantial width of the lip members 18 also provides a convenient ledge that may be covered with slip resistant paint. Like the posts 16, the lip members 18 are made preferably of extruded aluminum.
Further details of the structure of pool 10 can be observed in FIG. 2. A bracket 22, preferably of extruded aluminum, includes a U-shaped member 24 attached by nuts 26 and bolts 28 to provide two downwardly projecting lugs 30. The bracket 22 also includes a fastener-receiving channel 32 that is generally parallel to the top edge 20 of the wall 14. The bracket 22 is further provided with a pair of circular openings 33 as well as a central opening 34.
The lugs 30 are used to attach the bracket 22 to the top end of the corresponding post 16. One bracket 22 is provided for each post 16.
A bottom plate 35 carries two upstanding lugs 36 by which it is attached to the foot of the post 16 to form a base. A bottom rail 37, which engages the bottom edge 38 of the wall 14 is received by a channel 40 formed in the bottom plate 35. Each lip member 18 has a three-dimensional contour that provides a rolled under hook-shaped inner edge 42 and a downwardly projecting outer edge 44. A decorative colored plastic strip 46 is received in a channel 48 formed along the outer edge 44.
Each end of each lip member 18 is provided with a circular opening 50 and a generally radially oblong opening 52. A first fastener bolt 54 is inserted through the circular opening 50 of the lip member 18 and through one of the circular openings 33 of the bracket 22 to provide a first pivot point of connection (it is nut-engaged below bracket 22). The lip member 18 is thus limited to pivotal adjustment about the first fastener 54. A second fastener bolt 56 is inserted through the oblong opening 52 of the lip member 18 and engages nut 57 (shown in the breakaway) for sliding movement in the receiving channel 32 of the bracket 22 to provide a second point of connection. Since the second fastener bolt 56 can slide radially within the oblong opening 52 and the nut 57 can slide circumferentially within receiving channel 32, the lip member 18 is capable of sliding as well as pivotally adjusting about the second connection point. Thus each lip member end cooperates with bracket 22 and two fasteners 54 and 56 to form a means for connecting the end of the lip member 18 to a post 16 at an angle which is adjustable to allow for variation in the number of posts 16 (and hence angle) used in the construction of a particular pool.
A top rail 58 engages the top edge of the wall 14 beneath the lip member to provide rigidity and is received by a slot 60 formed along the radially inward edge of each bracket 22. A bracket cover 62, which blends the profiles of adjacent lip members 18, is secured over the top of each bracket 22 utilizing the central openings 39 and 34 for attachment. Three colored decorative plastic strips 64, 66 and 68 are held within vertical channels on the exterior surface of each post 16, and two such strips 64 and 68 cover the connection points of the bracket 22 and the bottom plate 35 to the post.
A unique feature of the pool construction described here is the adjustability of the angular position of the lip members 18 with respect to the posts 16. Since this angle can be varied, pools of various diameters can be constructed utilizing posts 16, lip members 18 and brackets 22 of standard dimensions. No modification, cutting or drilling of any of these components is necessary. The pool can be increased in size by simply inserting additional posts 16 and lip members 18 to enlarge the circle thus formed.
It will be obvious to those skilled in the art that the embodiment described above is intended to be merely exemplary and is susceptible of modification and variation without departing from the spirit and scope of the invention. For example, in the bracket 22 described here, the pair of circular openings 33 are disposed on the outside of the bracket 22 and the fastener receiving channel 32 is disposed on the inside. It would be possible to place the openings 33 on the inside and the channel 32 on the outside. It is also possible to vary the circular holes 50 by oblongation either radially or circumferentionally to provide even greater flexibility. Accordingly, the invention is not deemed to be limited except as defined by the appended claims. | A prefabricated swimming pool includes a liner and a wall supported by vertical posts. Lip members are arranged between the posts along the top edge of the wall and connected to the posts by brackets. The angles at which the lip members are attached to the posts are adjustable so that the number of posts used to support the wall can be varied, and pools of differing sizes can be constructed using standard components. | 4 |
RELATED APPLICATIONS
This application is the US National Stage under 35 USC 371 of PCT application PCT/EP2012/004888, filed on Nov. 27, 2012, which claims the benefit of the priority date of German application DE 10 2011 120 372.2, filed on Dec. 7, 2011. The content of the foregoing applications is incorporated herein by reference.
FIELD OF INVENTION
The invention relates to container processing, and in particular, to filling containers.
BACKGROUND
In the Trinox filling method, a probe-type tube that is open at both ends, sometimes called a “Trinox tube,” is used as a fill-level-determining element. The bottom end of the tube extends into the container, which is in a sealed position with the filler element.
To carry out the filling procedure, one begins by overfilling the container so that the fill level is above the desired fill level. As a result, the Trinox tube extends below the surface of the content. To reach the desired fill level, one applies a pressurized gas, sometimes referred to as a “Trinox gas,” to the container head space that is not occupied by the content. This forces content out of the container through the Trinox tube until the Trinox tube emerges from below the level of the content. At this point, the desired fill level is set.
A disadvantage of known methods is that the content ejected out of the container by of the Trinox tube is returned into the content vat. To the extent the ejected content has come in contact with a contaminated container, there is a risk that contaminated content will find its way into the content vat.
SUMMARY
The invention provides a way to avoid the risk that liquid content returned to the content vat will be contaminated.
In one aspect, the invention features a filler element that includes a housing, a channel formed therein, a valve in the channel, an opening downstream from the valve that dispenses content into a container when the valve is open, a tube for fill-level adjustment, a controlled gas channel, and a collection space. The tube, which adjusts a fill level of content in the container, projects past the dispensing opening and extends into an interior of the container during filling thereof. This tube connects to a collection space separated from a content vat from which the content comes through the channel. To adjust the desired fill level, a gas pressure is applied to the interior through the tube, thereby displacing excess content from the container. The controlled gas channel permits the gas to enter the container interior.
In another aspect, the invention features an apparatus for processing containers. Such an apparatus has a filler element for the filling of containers with liquid content. The filler element has a filler-element housing, a liquid channel formed in the filler element housing, a liquid valve in the liquid channel, a dispensing opening downstream from the liquid valve, with downstream being defined by a flow direction of the content, a tube for adjusting a desired fill level of content in the container, a controlled gas channel, and a collection space. The content is made available in a content vat from which content can flow through the liquid channel. The dispensing opening dispenses content into a particular container when the liquid valve is open. The tube has a first open end projecting past the dispensing opening and extending into an interior of the container during filling thereof. To adjust the desired fill level, a gas pressure is applied to the interior through the tube, thereby displacing excess content from the container. The controlled gas channel permits application of the gas into the container interior. The tube is connected to the collection space, which is separated from the content vat.
Some embodiments include a control valve that connects the tube to the collection space.
Other embodiments include a valve that connects the collection space to the content vat. This valve can be a stop valve, in some embodiments, or a switchover valve, in other embodiments.
Other embodiments include a pipe connected to the collection space for draining content. The collection space is connected to the pipe via a valve, which can be a stop valve or a switchover valve. Among these embodiments are those that further include an installation for processing the content, with the pipe being connected to the installation.
In some embodiments, collection space jointly serves a plurality of filler elements. Among these are embodiments in which the collection space is an annular channel.
Other embodiments include a rotary filling machine having a circulating rotor. In these embodiments, the filling element, together with a plurality of additional filling elements, is disposed on the circulating rotor.
In yet other embodiments, the tube is a trinox tube.
In another aspect, the invention features a method for filling a container with liquid content supplied from a content vat. Such a method includes extending a tube, for example, a trinox tube, into the container, upon completion of over-filling the container, passing gas through the tube to achieve a desired fill level of content by using gas pressure to force excess content out of a head space of the container, and causing content displaced by the gas pressure to be collected in a collection space separated from the content vat.
Some practices of the method include returning the content collected in the collection space to the content vat. Among these practices are those that include processing the content collected in the collection space prior to returning the content to the content vat.
Further developments, benefits and application possibilities of the invention arise also from the following description of examples of embodiments and from the figures. In this regard, all characteristics described and/or illustrated individually or in any combination are categorically the subject of the invention, regardless of their inclusion in the claims or reference to them. The content of the claims is also an integral part of the description.
As used herein, the word “containers” refers to cans, bottles, tubes, pouches, whether made of metal, glass and/or plastic, as well as other packaging means that are suitable for filling with liquid or viscous products.
As used herein, the term “fill-level-controlled filling” means a controlled filling of the containers such that, at the end of the particular filling process, they are filled with the liquid content up to a desired fill level.
As used herein, the term “fill-level-determining element” is an element, preferably a probe-type or tube-type element, that extends into the container during filling and with which the desired fill level is controlled and/or set.
As used herein, the words “basically” or “approximately” mean deviations from the exact value in each case by +/−−10%, and preferably by +/−5% and/or deviations in the form of changes not significant for function.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the invention will be apparent from the following detailed description and the accompanying figures, in which:
FIGS. 1-3 show simplified representations of a filling element of a filling system or a filling machine of a rotary design for the fill-level-controlled filling of containers in the form of bottles with liquid content.
DETAILED DESCRIPTION
FIG. 1 shows a filler element 1 mounted on part of a rotary filling machine for the fill-level-controlled filling of containers, in the form of bottles 2 , with liquid content.
The rotary filling machine has a multiplicity of the same kind of filler elements 1 on the circumference of a rotor 3 that can be driven to rotate around a vertical machine axis. An annular vat 4 supplies liquid content for all the filler elements 1 of the filling machine jointly.
During the filling operation, the annular vat 4 is partially filled with liquid content. As a result, within the annular vat 4 , there exists a lower liquid space 4 . 1 and, above it, a gas space 4 . 2 . For pressure filling of bottles, a pressurized inert gas, for example CO 2 gas, occupies the gas space 4 . 2 .
Three annular channels 5 , 6 , 7 have different functions depending on the filling method. The first annular channel 5 supplies a pressurized Trinox gas, i.e. a pressurized inert gas, which is for example CO 2 or nitrogen. The second annular channel 6 supplies a pressurized compressed gas, i.e. a pressurized inert gas, for example, CO 2 gas. The third annular channel 7 supplies a vacuum or negative pressure.
The filler element 1 comprises a filler element housing 8 , in which a liquid channel 9 is formed. A product pipe 10 connects an upper part of the liquid channel 9 to the lower liquid space 4 . 1 of the annular vat 4 by a product pipe 10 . On the underside of housing 8 , the liquid channel 9 forms an annular dispensing opening 11 through which, during filling, the liquid content flows into the bottle 2 . The bottle 2 has its bottle mouth lying in a sealed position against the filler element. A centering cone 12 provides the sealin the area of the dispensing opening 11 . A container carrier or bottle plate 13 raises the bottle into a sealed position against the filler element 1 .
A liquid valve 14 with a valve body 15 is provided in the liquid channel 9 . The valve body 15 interacts with a valve surface in the liquid channel 9 . It is made on a gas tube 16 arranged to be coaxial with a vertical filler element axis FA, or on a section of this gas tube 16 that has a widened cross-section. The valve body 15 acts as a valve plunger.
The gas tube 16 protrudes through the dispensing opening 11 above the underside of the filler element 1 and thus extends, during the filling, into the relevant bottle 2 or into a head space thereof. For the controlled opening and closing of the liquid valve 14 , an actuation device 17 , which is pneumatic in the illustrated embodiment, acts on the gas tube 16 . The actuating device 17 is housed in an inner space of the housing 8 , where it is separated and sealed from the liquid channel 9 .
The filler element 1 has a probe-type tube 18 arranged to be coaxial with a filler element axis FA. The gas tube 16 encloses, but is spaced apart from, this probe-type tube 18 . The probe-type tube 18 , or Trinox tube 18 , is open at both ends thereof. During the filling operation, a lower open end 18 . 1 of the tube 18 extends into the top area of the head space of the bottle and projects over the lower open end of the gas tube 16 .
The Trinox tube 18 is fed through the filler element housing 8 . A top section forming an upper end 18 . 2 projects over the top of the housing 8 and is held on a support arm 19 or support ring of an adjustment device 20 . Axial movement of the Trinox tube 18 in the direction shown by the double arrow A sets the fill level to which the bottles 2 are each filled with liquid content.
A control valve 21 connects the upper end 18 . 2 of the Trinox tube 18 to an annular channel 22 . The annular channel 22 is also common to all the filler elements 1 of the filling machine or the filling system. In the illustrated embodiment, the annular channel 22 serves as a content collection channel. The annular channel 22 , together with the control valve 21 , is provided on the support arm 19 .
A flexible pipe 23 connects the annular channel 22 to a preferably electrically-actuated switchover valve 24 . The switchover valve 24 selectively connects the annular channel 22 to the annular vat 4 . In doing so, the switchover valve 24 causes liquid content collected in the annular channel 22 to empty into either the content vat 4 or into a pipe 25 that leads to a content-processing installation.
The content-processing installation processes the content drained from the annular channel 22 during the emptying prior to returning it to the content vat 4 . Processing steps could include one or more of filtering, heating to a specified temperature, sterilizing, and carbonating. Following processing by the content-processing installation, the content is returned to the content vat 4 . Following these processing steps, the liquid content is fed to another use, for example returned to the content vat 4 .
The upper open end of the gas tube 16 , or a gas channel 27 formed between the inner surface of the gas tube 16 and the outer surface of the Trinox tube 18 , opens into a gas space 26 inside the housing 8 . In addition, various controlled gas paths with control valves 28 - 31 are provided in the housing 8 to connect the gas channel 27 to the annular channels 5 , 6 , 7 in a controlled manner as described in more detail below.
The filler element 1 thus makes it possible to pressure fill bottles 2 using the Trinox filling method. The filling operation starts with axially adjusting the tube 18 to set the desired fill-level. In particular, the lower open end 18 . 1 of the tube 18 defines the desired fill level (level N1) reached at the end of the filling process.
The liquid valve 14 and all the control valves 21 , 28 - 31 are initially closed. A bottle plate 13 raises the empty bottle against the filler element 1 and seals its bottle opening against the filler element 1 .
Next, the control valve 30 opens to create a connection between the annular channel 7 and the gas channel 27 connected to the inside of the bottle 2 . This evacuates the bottle 2 .
After evacuation, the control valve 30 is closed and the control valve 29 is opened. This connects the gas channel 27 to the annular channel 6 to pre-tension the inside of the bottle to the filling pressure with a pressurized inert gas. Before pre-tensioning the bottle, it is possible to purge the inside of the bottle with the inert gas one or more times. To carry this out, one simply carries out the activation sequence of the control valves 29 and 30 as described above as many times as desired.
After the pre-tensioning of the bottle 2 to the filling pressure, with the control valve 29 still open, the liquid valve 14 is opened. As a result, liquid content flows into the bottle through the annular dispensing opening 11 enclosing the gas tube 14 . The liquid content entering the bottle forces the inert gas out of the bottle and into the annular channel 6 through the gas channel 27 and the open control valve 29 . During this filling phase, the bottle 2 is deliberately overfilled to a level N2 above the level N1 of the desired fill level. Upon reaching the desired overfill level, liquid valve 14 closes to stop further flow of content into the bottle 2 .
With the bottle now overfilled, the control valve 28 is opened. This creates a connection between the annular channel 5 and the gas channel 27 . Pressurized Trinox gas from the annular channel 5 will then fill the head space in the bottle 2 . The control valve 21 is then opened so that the pressurized gas can force liquid content out of the inside of the bottle via the Trinox tube 18 into the annular channel 22 . This flow out the tube 18 ends once the the lower open end 18 . 1 of the Trinox tube 18 is no longer immersed in the contents. At this point, thus the desired fill level (level N1) will have been reached.
The filling process ends with closing the control valves 21 , 28 . With the liquid valve 14 still closed, for example by opening the valve 31 , a release or pre-release of the filled bottle 2 occurs. The bottle plate 13 then lowers the filled bottle from the filler element 1 .
It is clear that in particular the process steps before the actual filling phase can also be designed differently from the way described above.
With the filler element 1 or with the filling system having these filler elements, pressure filling is also possible.
In pressure filling, the Trinox tube 18 is used as a fill-level-determining gas return tube. At the end of the filling phase, inert gas forced out of the bottle is returned into the gas space 4 . 2 of the vat 4 . This is carried by closing control valves 28 - 31 , opening liquid valve 14 and control valve 21 , and causing the switchover valve 24 to connect the annular channel 22 and the gas space 4 . 2 . The inflow of the contents into the bottle 2 is automatically ended when the lower open end 18 . 1 of the Trinox tube 18 is immersed by the contents level of the contents that have entered the bottle 2 and a state of equilibrium has been reached between the level of the contents in the annular vat 4 and the content column formed in the Trinox tube 18 . The level of the lower open end 18 . 1 thus in turn determines the fill level (level N1) of the content in the particular bottle 2 .
FIG. 2 shows s a further embodiment, a filler element 1 a that differs from the filler element 1 in that the annular channel 22 is provided on the annular vat 4 and is connected firmly to the annular vat 4 by a pipe 32 . The switchover valve 24 and the pipe 25 are not provided. The filler element 1 a can carry out the same filling methods as the filler element 1 .
FIG. 3 shows an alternative filler element 1 b . This alternative embodiment is similar to the filler element 1 except that the annular channel 22 is likewise provided on the annular vat 4 and is connected to the control valve 21 by the flexible pipe 23 , and the pipe 25 is connected directly to the annular channel 22 . The filler element 1 b is suitable for Trinox filling methods with processing of the contents collected in the annular channel 22 .
The invention has been described above using examples of embodiments. It is clear that numerous modifications and variations are possible without thereby departing from the inventive idea underlying the invention. | A filler element includes a housing, a channel formed therein, a valve in the channel, an opening downstream from the valve that dispenses content into a container when the valve is open, a tube for fill-level adjustment, a controlled gas channel, and a collection space. The tube, which adjusts a fill level of content in the container, projects past the dispensing opening and extends into an interior of the container during filling thereof. This tube connects to a collection space separated from a content vat from which the content comes through the channel. To adjust the desired fill level, a gas pressure is applied to the interior through the tube, thereby displacing excess content from the container. The controlled gas channel permits the gas to enter the container interior. | 1 |
FIELD OF THE INVENTION
[0001] The present invention generally relates to article inspection and handling. The present invention more particularly relates to a method and apparatus for automatically visually inspecting and orienting blow-molded containers.
BACKGROUND
[0002] In the manufacture and packaging of blow-molded articles, such as hollow plastic containers or bottles, it is necessary that the containers be of uniform size and shape, and be free of defect. Additionally, scrap material from the manufacturing process may need to be separated from the blow molded articles before the blow-molded articles are packaged or further processed.
[0003] In the manufacture of blow molded bottles, the blow-molding operation results in th formation of “tail” at the closed end of the bottle, which tail must be snapped of, this generally being accomplished during removal of the bottle from the blow-molding machine. The blow-molding operation also results in the formation of a ringlike collar (also known as a “moil”) around the opening to the bottle, which moil is cut off from the molded bottle substantially upon completion of the molding operation. The blow-molded bottles, tails and moils are then generally discharged from the blow-molding machine, and must be later separated before further processing.
[0004] Further processing may include inspecting and orienting of the blow-molded bottles prior to filling, packaging, or other bottle handling operation. The blow-molded bottles may be fed to an inspection device where the bottles may be manually or automatically inspected. The bottles may also be fed to an unscrambling device where they are unscrambled.
[0005] The use of a large number of varying-sized articles to orient and/or package poses a particular problem to the manufacturing and packaging industries because they oftentimes are designed for a fixed size article. Thus, in order to change from one size container to another, for example, the various machinery, tooling, parts (such as guide arms, unscrambler bowl, etc.), had to be “changed out” before the machinery could accommodate another size. This change over not only results in additional costs, but also results in lost revenue due to down time.
[0006] Accordingly, there is a need in the industry for a cost effective and operationally efficient inspection and alignment apparatus and method for blow molded articles.
SUMMARY OF THE INVENTION
[0007] An objective of the present invention is to provide method and apparatus for inspecting and orienting manufactured articles, such as blow-molded containers.
[0008] According to one aspect of the present invention, an apparatus is disclosed that includes an article receiving station, a waste separation station, an inspection station, and a conveyance device for transporting articles between the article receiving station, the waste separation station, and the inspection station. The conveyance device recirculates articles not removed from inspection station back to the article receiving station.
[0009] Another aspect of the present invention is to provide an article inspecting and orienting apparatus including an article receiving station, a waste separation station, an article leveling station, an inspection station, and a conveyance device for transporting articles between the article receiving station, the waste separation station, and the inspection station. The conveyance device recirculates articles not removed from inspection station back to the article receiving station.
[0010] Another aspect of the present invention is to provide a method of inspecting and orienting a plurality of articles including the steps of receiving a plurality of articles from a manufacturing process at a receiving station, separating manufacturing waste from the plurality of articles, providing the plurality of articles to an inspection station, inspecting the received plurality of articles, removing defective articles from the plurality of articles that fail inspection, orienting acceptable articles from the plurality of articles that pass inspection, and recirculating remaining articles that pass through the inspection station to the receiving station.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Referring now to the figures, which are exemplary embodiments, and wherein the like elements are numbered alike:
[0012] FIG. 1 illustrates a perspective view of an inspection and orienting apparatus according to an embodiment of the disclosure.
[0013] FIG. 2 illustrates a partial cutaway, perspective view of the inspection and orienting apparatus of FIG. 1 .
[0014] FIG. 3 illustrates another partial cutaway, perspective view of the inspection and orienting apparatus of FIG. 1 .
[0015] FIG. 4 illustrates a top view of the inspection and orienting apparatus of FIG. 1 .
[0016] FIG. 5 illustrates a perspective view of the second section of the conveyance device according to an embodiment of the disclosure.
[0017] FIG. 6 illustrates a perspective view of the leveling device according to an embodiment of the disclosure.
[0018] FIG. 7 illustrates a top view of an embodiment and inspection and orienting apparatus according to another embodiment of the disclosure.
[0019] FIG. 8 illustrates a simplified top view of the inspection and orienting apparatus of FIG. 1 .
DETAILED DESCRIPTION
[0020] Specific embodiments of systems and processes for inspecting and orienting articles according to the invention are described below with reference to the drawings.
[0021] FIGS. 1-4 illustrate an apparatus 100 for inspecting and orienting articles 105 according to an embodiment of the disclosure. Referring to FIGS. 1-4 , the apparatus 100 includes a housing 110 having a generally rectangular footprint. In another embodiment, the housing 110 may have a rectangular, square, or other footprint geometry capable of housing inspection and orienting components of the apparatus 100 .
[0022] The apparatus 100 further includes a conveyance device 120 for conveying articles 105 between various stations within the apparatus 100 . In this embodiment, the conveyance device 120 includes a first section 122 , a second section 124 , and a third section 126 . In another embodiment, the conveyance device 120 may include one or more sections.
[0023] In this exemplary embodiment, the first, second and third sections 122 , 124 , 126 are belt conveyors. The first, second, and third sections 12 , 124 , 126 include a conveyor belt 140 having an upward facing belt surface 142 and a drive (not shown) for causing the conveyor belt system 140 to move. The conveyor belt 140 of the different sections have different lengths. In another embodiment, the conveyor 140 of one or more of the sections may have the same length.
[0024] The first section 122 further includes a plurality of evenly spaced support dividers 123 . The support dividers 123 are structures that are at least partially protruding or above the belt surface 142 . The support dividers 123 may support, divide, and/or stabilize articles 105 on the belt surface 142 as the articles are moved up an inclined conveyor belt. In another embodiment, one or all of the first, second, and third sections 122 , 124 , 126 may be or may include a belt conveyor, matt top conveyor, roller conveyor, chute or slide or other similar article transport.
[0025] The apparatus 100 further includes an article receiving station 200 configured to receive articles 105 from an article source (not shown). The article receiving station 200 may be a chute, opening or other receiving area for receiving articles 105 onto the first section 122 from an article source. The article source may be a chute, belt, conveyor, manual feed, or other similar article providing device or means for providing and/or loading articles onto the first section 122 . In addition to articles 105 , the first section 122 may receive manufacturing waste 106 . The manufacturing waste 106 may include, but is not limited to tails 107 and moils 108 . The apparatus 100 may further include a second article receiving station 201 for receiving articles 105 from an article source. The second article receiving station 201 is an opening in the housing 110 that allows for articles 105 to be placed, fed or otherwise received on the second section 124 . In yet another embodiment, the apparatus 100 may include one or more article receiving stations positioned at different locations on the first section 122 . The first section 122 transports the articles 105 and any manufacturing waste 106 from the article receiving station 200 to a waste separation station 300 . At the waste separation station 300 , manufacturing waste 106 is separated from articles 105 .
[0026] In this exemplary embodiment, the waste separation station 300 includes an open bar grid 310 configured to support articles 105 while allowing manufacturing waste 106 to pass through to a waste discharge chute 320 . The waste separation station 300 may include a transverse grid of ¼ inch rods 302 that form a screen and angled chute. In one embodiment, the rods 302 may be ¼ inch rods. In another embodiment, the rods 302 may have a diameter between about ⅛ inch and about ½ inch. In another embodiment, the rods 302 are of a diameter selected to support the articles 105 while passing manufacturing waste 106 therethrough. The rods 302 are perpendicular to the movement of the conveyor belt 140 , and thereby orient the manufacturing waste 106 , especially the tails 107 , with the rods 302 to effectively remove the manufacturing waste 106 , especially the tails 107 , by passing the manufacturing waste 106 through the space between the rods 302 . The waste discharge chute 320 discharges manufacturing waste 106 from the apparatus 100 . In another embodiment, the waste separation station may include a grid, screen, automated waste removal device, such as, but not limited to a robotic visually guided arm, vacuum removal system or other devices configured to remove manufacturing waste 106 from the articles 105 .
[0027] The articles 105 are transported from the waste separation station 300 to the second section 124 . In this exemplary embodiment, the articles 105 are transported from the waste separation station 300 to the second station by gravity feed from the angle of the chute formed by the rods 302 . In another embodiment, the articles 105 may be transported from the waste separation station 300 to the second section 124 by a conveyor, scraper, bar, chute or other similar transport device.
[0028] The articles 105 are transported by the second section 124 to an article leveling station 400 . The article leveling station 400 will be described with reference to FIGS. 5 and 6 . The article leveling station 400 includes a leveling device 410 . The article leveling device 410 includes a paddle wheel 420 . The leveling device 410 further includes a motor 430 configured to drive the paddle wheel 420 . In this exemplary embodiment, the paddle wheel 420 include four paddles 422 . In another embodiment, the paddle wheel 420 may include one or more paddles 422 . The paddle wheel 420 is driven by the motor 430 to rotate above the conveyor belt 140 to level the articles over the conveyor belt 140 . In other words, the article leveling station orients the articles 105 such that a major thickness axis is oriented parallel to the belt surface 142 . In other words, the leveling device 410 creates a single layer of articles 105 on the conveyor belt 140 by re-orienting leaning, stacked or other non-conforming articles 105 to form a single layer. The paddles 422 may be formed of a complaint or soft material, such as but not limited to rubber, fabric or polymeric material so as to not damage the articles 105 . This may be particularly important when the articles 105 are still warm or hot from manufacturing and may be easily damaged. The conveyor belt 140 then transports the articles to an article inspection station 500 .
[0029] Referring again to FIGS. 1-4 , the inspection station 500 includes at least one automated device 510 . In this exemplary embodiment, the automated device 510 is a vision guided robot configured to identify and remove articles 105 determined to be defective and being transported through the inspection station 500 by the conveyor belt 140 . In another embodiment, the automated device 510 may include vision and pick and place devices capable of identifying and moving articles 105 within the apparatus 100 . The vision guided robot includes software and hardware capable of identifying articles 105 which are determined to be outside of one or more acceptable design criteria, or in other words, defective. The vision guided robot further includes a removal device 511 for removing defective articles 105 from the conveyor belt 140 . In this exemplary embodiment, the removal device 511 is a vacuum pad or nozzle that is brought in contact with an article 105 so as to temporarily attach to the article 105 , thereby allowing the article 105 to be lifted from or otherwise removed from the conveyor belt 140 . In another embodiment, the removal device 511 may be a mechanical gripper or other attachment device. The automated device 510 then places any removed articles onto a defective article chute 520 (see particularly FIG. 4 for an articles 105 placed on the chute 520 ) for removal from the apparatus 100 . Removed articles 105 may then be collected and/or recycled for further processing.
[0030] In addition to removing articles 105 determined to be defective from the conveyor belt 140 , the automated device 510 further selects articles determined to meet acceptable design criteria and similarly removes the acceptable articles 105 from the conveyor belt 140 . The acceptable articles 105 are placed in a predetermined oriented position on a discharge conveyance device 540 . The automated device 510 further includes software and hardware configured to determine acceptable design criteria and place the acceptable articles 105 in a predetermined orientation upon the discharge conveyance device 540 . The discharge conveyance device 540 includes a conveyor belt 542 having an upward facing belt surface 544 and a drive (not shown) for causing the conveyor belt 542 to move. The conveyor belt 542 includes perforations 546 .
[0031] Referring again to FIGS. 1-4 , the apparatus 100 further includes an air vacuum device 143 configured to draw air through perforations 546 in the belt surface 544 . The air vacuum device 143 includes a vacuum blower 145 and various conduits, ducting, and vacuum flow devices (not shown) configured to apply a vacuum to a bottom surface (not shown) of the conveyor belt 542 . The drawn air creates an object-stabilizing suction force on articles 105 located on the belt surface 544 when the conveyor belt 542 moves relative to the air vacuum device 143 . In one embodiment, the conveyance device 100 may include a control (not shown) for changing the suction force imposed on the articles 105 while being transported on the belt surface 544 . In another embodiment, the discharge conveyance device 540 may be a conveyor belt, mat top conveyor, roller conveyor, cable conveyor, table top chain conveyor or other similar article transport device.
[0032] FIG. 7 illustrates another exemplary embodiment of the apparatus 100 . As can be seen in FIG. 7 , the inspection station 500 includes a first automated device 512 and a second automated device 514 . The first automated device 512 is configured to determine those articles 105 that meet acceptable design criteria, remove those articles 105 from the conveyor belt 542 , and place those articles 105 in a predetermined orientation upon the discharge conveyance device 540 . The second automated device 514 is configured to determine those articles 105 that do not meet acceptable design criteria or in other words are defective, remove those articles 105 from the conveyor belt 542 , and place those articles on defective article chute 520 for removal from the apparatus 100 . In another embodiment, the inspection station 500 may include one or more automated devices 514 .
[0033] Referring to FIGS. 2-4 and 8 , the articles 105 , after passing through the inspection station 500 , are transported by the second section 124 to the third section 126 for return to the first section 122 . The third section 126 may a cross-feed belt conveyor. In another embodiment, the third section 126 may be a belt conveyor, roller conveyor, mat conveyor, chute or slide or other similar article transport device. In one embodiment, the third section 124 may be of a narrow conveyor belt width compared to the second section 124 in order to facilitate the transport of the articles 105 from the second section 124 to the first section 122 . In such a manner, articles 105 and manufacturing waste 106 not removed by the apparatus 100 are recycled through the article receiving station 200 , the waste separation station 300 , the article leveling station 400 , and the inspection station 500 . The recycling of the articles 105 and manufacturing waste 106 allows for the additional opportunities for manufacturing waste 106 and articles 105 determined to be defective to be removed, as well as articles 105 deemed to be acceptable to be oriented. This is accomplished by the repositioning and/or re-orienting of the articles 105 and manufacturing waste 106 during recirculation process.
[0034] Referring to FIG. 1 , the apparatus 100 further includes a control system 101 to operate the various components of the apparatus, including, but not limited to the operation of the conveyance device 120 , at least one automated devices 510 , the article leveling device 410 , and the air vacuum device 143 . The control system 101 may include any number of manual and automated systems for performing the apparatus functions.
[0035] Referring to FIGS. 2 , 3 , 4 and 8 , the conveyance device 120 includes sections that are inclined and/or at different horizontal levels or heights. In this exemplary embodiment, the first section 122 is inclined upward from an initial position 610 below the third section 126 to a final position 615 above the waste separation station 300 . The waste separation station 300 is inclined downward from an initial position 310 below the first section 122 to a final position 315 proximate the second section 124 . The second section 124 is approximately level and extends from an initial position 620 proximate the final position 315 of the separation station 300 to a final position 625 above the third section 126 . The third section 126 extends approximately level from an initial position 630 below the final position 625 of the second section 124 to a final position 635 above the initial section 610 of the first section 122 . In such a manner, the conveyance device 120 and separation station 300 form a continuous loop that recirculates articles 105 through the apparatus 100 to re-orients and/or repositions articles and manufacturing waste 106 to be further separated and/or identified and/or classified as acceptable or defective. In another embodiment, any one or combination of the sections and/or separation station 300 may be at the same or different heights and/or inclinations.
[0036] While the invention has been described with reference to various exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. | The present invention relates to an apparatus and methods for inspecting and orienting manufactured articles. The apparatus and method include recirculating inspected articles to the inspection station for additional processing. | 6 |
FIELD OF THE INVENTION
The present invention relates generally to molding methods, and more particularly to a method of molding a sensitive member, such as an electrical element, within a one-piece plastic housing for ease of installation within a desired device where the electrical element is completely shielded from the ambient atmosphere so as to prevent contamination and degradation of the electrical element during use.
BACKGROUND OF THE INVENTION
Molding of plastic materials has become increasingly more complex in connection with the provision of finished components for use in a wide variety of applications. Two advanced methods of molding include insert molding and premolding/overmolding processes.
Insert molding typically includes providing some type of insert, usually formed from a non-plastic material such as metal or the like, within a mold of a molding machine. Thereafter, plastic material is injected about the insert or desired portions thereof so as to complete the component.
In a premolding/overmolding process, a premold element is typically provided with a predetermined configuration in a first mold of a molding machine. After removal of the premold element from the first mold, the premold element is inserted within a second mold of a molding machine so as to "overmold" more plastic about the premold element or selected areas thereof.
During injection molding, obtaining a hermetic seal between components is not possible. Depending on the environment and the desired finished component, a hermetically sealed component can be a desirable feature.
This is particularly true when a sensitive insert, such as an electrical element, is molded in an insert molding process. With such an electrical element, it is typically desirable to provide protection against degradation of the electrical component over time which can occur from the ambient atmosphere or from exposure to materials or fluids during use.
It therefore would be desirable to provide a method for molding a one-piece plastic electrical component having a sensitive electrical element formed therein where the electrical element is completely shielded from the ambient atmosphere so as to prevent contamination and degradation of the electrical element during use.
SUMMARY OF THE INVENTION
The invention comprises a method of molding an electrical element within an associated housing so as to provide a one-piece finished component which prevents exposure of the electrical element to the ambient atmosphere thereby eliminating contamination and degradation of the electrical element. The method includes insert molding the electrical element within a premold member and then overmolding selected portions of the premold member and electrical element with an overmold member.
After molding, unmolded areas are shielded from the ambient atmosphere so as to provide the finished one-piece component where the electrical element is hermetically sealed. Portions of the premold member and the electrical element are provided to hold those members during molding of the overmold member.
A plurality of components are preferably molded simultaneously with a portion of the electrical element of each component serving to hold adjacent components together. During or after molding, selected areas of the electrical element are trimmed so as to form the desired circuit of the component.
BRIEF DESCRIPTION OF THE DRAWINGS
Various other features and attendant advantages of the present invention will become more apparent from the following detailed description, when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts throughout the several views, and wherein:
FIG. 1 is a perspective, longitudinal, cross-sectional view of a one-piece component of the invention illustrating the electrical element, the premold element and the overmold element thereof;
FIG. 2 is a top plan view of the electrical element of the invention;
FIG. 3 is a perspective cross-sectional view of the electrical element premolded with the premold element;
FIG. 4 is a cross-sectional view of the component taken along line 4--4 of FIG. 1 and in the direction indicated;
FIG. 5 is a top plan view of the component illustrated in FIG. 1; and
FIG. 6 is a side elevational exploded view of a prior art electrical component.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a component provided by the method of the invention is designated generally by the reference numeral 10. The method provides a component 10 formed to provide a one-piece member and substantially includes an electrical element or leadframe 12, a first premold element 14 and a second overmold element 16.
In the present specification and drawings, the component 10 is depicted as a fuel line vapor sensor utilized in vehicle fuel systems. It is to be understood, however, that the method of the present invention can provide a component 10 for use in a variety of applications without departing from the teachings of the present invention.
To form the finished component 10, the electrical element 12 is positioned within a mold of a molding machine (not illustrated) and the first premold element 14 is molded thereabout. Upon removal from the molding machine, an intermediate insert molded element 18, illustrated in detail in FIG. 3, is provided including both the electrical element 12 and the first premold element 14.
The insert molded element 18 is then positioned in another mold of a molding machine (not illustrated) and the second overmold element 16 is molded about selected areas of both the electrical element 12 and the first premold element 14. Upon removal from the mold, the finished component 10 as illustrated in FIGS. 1, 4 and 5 is provided. Details of the component 10 and its molding will now be provided.
As FIG. 2 illustrates, the electrical element 12 is preferably stamped from a desired conductive metal and includes, inter alia, a central portion 20, three electrical contacts 22 and an outer frame or "halo" member 24. The particular material and shape of the electrical element 12, however, can vary.
The central portion 20 typically creates the desired electronic circuit, but can vary. Preferably, an electronic fuel sensor element (not illustrated) is mounted upon the central portion 20 after molding.
As FIG. 1 illustrates, the electrical contacts 22 extend to the exterior of both the premold element 14 and the overmold element 16 for connection to a desired electrical lead or other component (not illustrated). The outer frame 24 primarily serves to hold the central portion 20 in position during premolding and overmolding and is preferably connected to the central portion 20 by seven connecting legs 26a-26g. Each leg 26a-26g is cut or trimmed during or after final molding of the overmold element 16.
As FIG. 3 illustrates, the premold element 14 is molded about predetermined portions of the central portion 20 of the electrical element 12. As described in detail below, the premold element 14 is designed in such a way that any seams between the premold element 14 and the overmold element 16 are provided in predetermined areas which can be shielded by subsequent processing.
The premold element 14 substantially includes a top surface 28, a bottom surface 30, and first and second pockets 32 and 34. The pockets 32 and 34 are utilized to hold the premold element 14 within cores or cavities (not illustrated) during overmolding of the overmold element 16 to prevent any floating in the x or y direction as plastic is injected within the overmold cavities. To prevent floating of the premold element 14 in the z direction, the outer frame 24 of the electrical element 12 is utilized to retain the premold element 14 within the cavities.
As FIGS. 1 and 4 illustrate, the bottom surface 30 of the premold element 14 is encapsulated by the overmold element 16. The top surface 28 and pockets 32 and 34, however, remain substantially exposed to the exterior of the finished component 10.
As FIGS. 4 and 5 illustrate, the premold element 14 includes a peripheral shoulder 36 formed thereabout. The shoulder 36 includes an outwardly tapered edge 38 having a top line 40 which forms the seam between the periphery of the premold element 14 and the overmold element 16.
Accordingly, the interface between the top surface 28 of the premold element 14 and the overmold element 16 is provided along the tapered edge 38 with exposure of the seam formed therebetween to ambient atmosphere confined along the top line 40. Thus, in order to form a hermetic seal between the premold element 14 and the overmold element 16, only the top line 40 must be sealed or shielded.
Preferably, a cover member (not illustrated) is provided having a depending lip for engagement within a channel or glue track 42 formed about the premold element 14 between the premold element 14 and the overmold element 16. The cover member is secured along the top line 40 with an adhesive or the like.
The cover member thus seals the central portion 20 of the electrical element 12 and the pockets 32 and 34 of the premold element 14 from ambient atmosphere. As FIG. 5 illustrates, after removal of the outer frame 24, the only portions of the electrical element 12 exposed to atmosphere are portions 44 and 46. After molding of the component 10, however, the portions 44 and 46 are filled with a potting compound or the like thereby sealing them from exposure to ambient atmosphere.
As FIG. 1 illustrates, if desired, a button 48, preferably made of glass and having an aperture 50 therethrough, can be positioned within the pocket 34 for mounting of the fuel sensor (not illustrated) thereon. The aperture 50 communicates with a hollow stem 52 formed with the overmold member 16 for communicating fuel vapors to the sensor.
FIG. 6 illustrates a prior art component 110 which is comprised of a housing 112, a cover member 114 and a backplate 116. An electrical sensor or element (not illustrated) is attached to the backplate 116 for connection with the electrical element or leadframe and terminals (not illustrated) within the housing 112.
Accordingly, the prior art components 110 were assembled individually. The backplate 116, with its attached electrical sensor, was glued onto the housing 112 with the sensor being electrically connected to the terminals by wire bonding. The cover 114 was then glued onto the housing 112.
The method of molding the component 10 of the present invention overcomes the problems associated with the complex prior art component 110 by providing a sealed one-piece component 10 for easy assembly and complete protection of the electrical element 12. Thus, significant costs savings in materials and manufacturing are realized.
Modifications and variations of the present invention are possible in light of the above teachings. It is to be understood that within the scope of the claims the invention may be practiced other than specifically described. | A method of molding an electrical element within an associated plastic housing so as to provide a one-piece finished component where the electrical element, joints between the electrical element and the housing, and seams between a premold portion and an overmold portion of the plastic housing are designed and positioned for shielding from ambient atmosphere so that the electrical element is protected from contamination and degradation from the elements. | 1 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 61/450,451 filed on Mar. 8, 2011, entitled “Low Drag Automotive Piston.”
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to reciprocating engines and piston designs, particularly in the automotive field. More specifically, the present invention pertains to a high efficiency piston that reduces viscous drag and mechanical losses as it translates through its range of motion from bottom dead center (BDC) to top dead center (TDC) within a reciprocating engine.
Reciprocating engines utilize a piston-cylinder configuration to capture the power of expanding gases to create work in the form of translation of the piston within the cylinder, which in turn rotates a crank to power a vehicle, operate an electrical generator or perform a duty unto which rotating mechanical power is a motive input. An engine piston is positioned within a cylinder with minimal clearance and tight tolerancing, wherein the interface between the piston and cylinder bore is heavily lubricated via the continual application of oil along the cylinder walls during operation. Proper oiling of the cylinder during engine operation is critical to controlling and preventing excessive thermal load build-up, frictional losses and even engine seizure. Typical piston-cylinder devices are comprised of a metallic structure, which expands readily under thermal load. Intense heat due to the ignition of the engine fuel-air mixture within the cylinder conducts through the walls of both the piston and cylinder, resulting in a large thermal flux and the relative expansion of components within the engine. To prevent these components from expanding excessively and clashing with one another, proper lubrication and engine design is critical, and further reduces frictional wear and improves engine longevity.
The interface between the piston and cylinder of a reciprocating engine is a piston ring device. Piston rings are peripherally mounted about the outer diameter of the piston head and are positioned within grooves therealong. The piston rings are generally semi-circular rings that are allowed to expand under thermal load without creating an interference, while their positioning on the cylinder head serves two primary functions. The first of which is to prevent the fuel-air mixture within the piston from bypassing the piston head during expansion, and thus retaining proper compression within the cylinder and allowing the expanding gases to convert its kinetic energy into piston work as designed. The second function of the piston rings is to skim oil from the cylinder bore as it translates therein. Oil is sprayed along the piston interior bore to facilitate reduced friction and heat, and thus reduced wear. The piston ring leave a lubricating oil film of a few micrometers thick on the bore surface, so as the piston descends along its path within the cylinder, the thin film provides adequate lubrication, heat dissipation and thus reduced wear on the engine. Piston rings can thus be differentiated as either compression rings and oil control rings, wherein their moniker denotes their function. Most reciprocating engines employ a plurality of piston rings for the foregoing functions, wherein one or a plurality of a single piston ring type may be deployed for improved function and thus improved compression sealing and oil control. Dual compression rings may prevent undesired loss of compression, while dual oil control rings prevent build-up of oil along the bore if the oil is less than uniform, and further prevent oil from entering the fuel-air mixture and burning.
While piston rings may facilitate a thin film of lubrication, there still exits friction between the piston and the cylinder during operation, in the form of viscous drag (fluid friction) and mechanical friction. The present invention relates to a piston design that is adapted to provide improved mechanical efficiency, smoother operation of the engine and lower emissions as the life of the engine increases. Typical pistons employ a cylindrical head and a similarly cylindrical piston skirt, which extends over the connection to the piston rod. As such engines increase in temperature and even begin to overheat (if adequate cooling is not provided), expansion under thermal load occurs, leading to increased friction between the piston and cylinder bore and potentially a seizure of the engine itself, as the friction between the components becomes too great or they fuse together under intense heat.
The present invention is specifically related to a piston shape that comprises a cylindrical piston head, wherein the piston skirt is a tapered shape having an inwardly concave central portion before terminating at a lower portion of equal radius as the upper piston head. This shape allows the piston to dissipate heat through the lower portion and reduces expansion under considerable thermal load, while the concave shape allows for material growth without risking seizure of the engine. Current piston designs have considerably high mechanical losses with regard to the energy wasted from the expanding gases in the form of mechanical friction and oil drag. The present invention is a more efficient component that not only reduces these power robbing elements, but also decreases the amount of fuel needed to efficiently operate the engine, while also increasing the longevity of any engine equipped with the present piston configuration. Hydrocarbon emissions are also reduced, as the piston rings are more effective at sealing the combustion chamber and less oil is burned during an engine cycle. The present invention is designed to provide an engine that runs quiter, cooler, and still prevents excessive oil consumption in excessively high mileage vehicles.
2. Description of the Prior Art
Several devices have been disclosed in the prior art that relate to piston designs and those that relate to improved mechanical efficiency. Several devices have been patented or disclosed in published patent applications. These devices have familiar design elements for the purposes of providing a new piston configuration for a reciprocating engine; however none are provided in the configuration as disclosed in the present invention. The disclosures deemed most relevant to the present invention are described below.
Specifically, U.S. Pat. No. 6,206,248 to Popp, U.S. Pat. No. 4,809,591 to Rhodes, and U.S. Pat. No. 4,648,309 to Schellmann all disclose pistons having a particular shape so as to reduce friction and wear on the inner bore of a cylinder. These devices include piston skirts that comprise inwardly shaped profiles, but fail to disclose a concave shape having a recessed pin boss and a lower oil control ring to facilitate reduced friction and improved lubrication throughout the engine cycle. These prior art devices are well adapted for their particular purpose, but fail to disclose a piston having an inwardly concave central portion with a first and second oil control ring on either side of the concave portion.
The present invention provides a new and improved piston shape that reduces potential contact area between the central portion of the piston and the cylinder bore, while also improving lubrication in the form of a plurality of oil control rings surrounding the inwardly concave central portion of the piston. The result is reduced friction, reduced mechanical losses, increased heat dissipation and a smoother running engine that can reduce wear in high mileage engines. It is submitted that the present invention is substantially divergent in design elements from the prior art, and consequently it is clear that there is a need in the art for an improvement to existing devices. In this regard the instant invention substantially fulfills these needs.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of low drag pistons now present in the prior art, the present invention provides a new reciprocating engine piston wherein the same can be utilized for providing convenience for the user when reducing mechanical losses, friction and improving efficiency of a reciprocating engine.
It is therefore an object of the present invention to provide a new and improved piston device that has all of the advantages of the prior art and none of the disadvantages.
It is another object of the present invention to provide a new reciprocating engine piston that is adapted to reduce mechanical friction, viscous drag and improve thermal load dissipation under high heat conditions.
Another object of the present invention is to provide a new reciprocating engine piston that reduces wear by having improved clearance between the piston and cylinder along the central portion of the cylinder, improving mechanical efficiency and longevity of the engine.
Yet another object of the present invention is to provide new reciprocating engine piston that incorporates a first and second oil control ring above and below its recessed central portion, allowing improved oil control, lubrication and reduced oil burning.
Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTIONS OF THE DRAWINGS
Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout.
FIG. 1 shows an side view of the piston of the present invention.
FIG. 2 shows an overhead view of the piston of the present invention.
FIG. 3 shows a cross section view of the present invention in operation within a reciprocating engine.
FIG. 4 shows an underside view of the present invention.
FIG. 5 shows another side view of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the low drag piston. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for reducing friction, mechanical losses and improving engine efficiency within a reciprocating engine. The figures are intended for representative purposes only and should not be considered to be limiting in any respect.
Referring now to FIG. 1 through 5 , there is shown a view of the low drag piston of the present invention. The piston 11 is a cylindrical device adapted to travel within a reciprocating engine and utilize the power of an expanding fuel-air mixture to turn a crank shaft. Its function is to utilize the expanding gases while sealing the combustion chamber and controlling lubrication along the interface between the piston and the bore of a cylinder. The present invention comprises a piston crown 17 having a largely cylindrical shape, connected to a recessed central region 12 and terminating in a lower piston skirt portion that is of equate diameter as the piston crown region. This shape reduces the contact areas for which the piston can contact the inner cylinder walls during operation, wherein thermal expansion is accounted for to reduce increased friction and wear. The crow region 17 further comprises a plurality of piston ring grooves, including at least one compression ring groove 15 , 16 , and a first oil control ring groove 14 . The compression ring grooves are adapted to secure piston rings that prevent the expanding fuel-air mixture within the compression chamber from bypassing the piston crown, and thus creating a sealed compression chamber to harness the full energy potential of the expanding gases. The first oil control ring groove 14 is adapted to secure a piston ring that controls the thickness of a layer of oil along the cylinder walls, such that the piston and cylinder are adequately lubricated throughout the motion of the piston. This groove may include a plurality of oil apertures within the groove 14 to divert the flow of oil.
Along the lower piston skirt portion is a second oil control groove, which provides further control of the lubrication within the reciprocating engine and prevents increased friction, wear and heat build-up. Between the piston crown 17 region and the lower skirt portion is a recessed area 12 that is inwardly concave and provides connection 18 to the piston pin boss. This inwardly concave area 12 draws the shape of the piston away from the walls of the cylinder to reduce potential contact points as the piston and cylinder undergo thermal expansion during operation.
Strict attention is paid to the shape of the piston component and by strategically placing a second oil control ring on the lower portion of the piston skirt, greater operating efficiency is attained. Aside from the concave central portion of the skirt and pin boss that surrounds the entire piston circumference, there is the aforementioned oil control ring, similar in design to the piston crown region. The present invention contemplates either single or dual compression rings, while providing a first and second oil control ring on either side of the recessed skirt area 12 .
Construction of the piston may be accomplished via casting or forging aluminum alloy. To cast a piston, aluminum alloy ingots are heated until molten then poured into preheated molds. The raw casting is then cooled gradually in a controlled environment then separated from the mold to be reheated later to a lower temperature to allow the alloy to stabilize. The casting is then inspected for defects, sonic tested for consistency then degreased. It is then turned on a lathe to create the general shape of the finished product. It is turned a second or third time to achieve the final dimensions of the finished piston. The piston is then ready for drilling. The wrist pin hole is drilled through the pin boss and then small oil drain holes in the ring grooves for the oil control rings. The pin boss hole is then polished along with the lands and crown. Engraving important information then becomes necessary. The piston is washed and dried in preparation for an anodized finish. Other scuff resistant finishes include tin and graphite. Piston rings are carefully sized before fitting. Compression is controlled by milling or dishing in the piston crown. If forging is preferred by certain manufacturers for racing or heavy duty use, the new design lends itself to this construction method as well. Forging a piston requires cutting a solid piece of aluminum rod into appropriate lengths. These slugs are then heated up in an oven and then sent to a punch press that has been preheated to the same temperature of about 500 degrees Fahrenheit. The slug is then removed from the oven and before it has a chance to cool is hammered by the press using 2,000 tons of pressure. There are dies above, below, and all around the slug that give it the basic shape of a finished piston. The forging requires an hour to cool down. The forging must then be heat treated in an oven. This process tempers the forging. The forging is allowed to cool then is sent through the oven again at a lower temperature to stabilize the forging. It is then turned on a lathe. Once to give the basic shape of the end product, then again to finish the new piston to its exact dimensions as well as to cut and polish ring grooves. Next the wrist pin hole is drilled along with the oil drain holes of the oil control rings. Finally the piston crown is milled to give the desired compression ratio then engraved to with pertinent information. The rings are made and sized to fit the piston. The freshly minted piston is then washed and prepared for use.
The present low drag piston of the present invention is designed to curtail oil consumption through a more efficient scraping of oil along the cylinder walls while reducing piston expansion if an engine should somehow overheat, extending engine life and reliability. It is contemplated that a 1.5 to 2.0 mile increase per gallon in a four or six cylinder automotive engine may be created through the use of the present invention, while less oil is mixed with the contaminates of combustion to reduce emissions and oil consumption. Most automotive engineers simply rely on synthetic and high end lubricants to deal with these problems. The present invention creates a new piston design that can overcome nonuniform oil viscosity and density by providing dual oil control rings and a recessed skirt portion to improve lubrication and engine efficiency. As engine rotational speed approach mid-range for a particular engine design, more oil is thrown onto cylinder bores by the crankshaft that must be scraped therefrom by oil control rings below the lower compression ring. As quickly as the oil is thrown onto the bores, it must be scraped off so as not to impede piston motion. This impediment requires a richer (stronger) fuel mixture to enable the pistons to continue working, which in turn causes higher peak hydrocarbon and carbon monoxide emissions. Then as the engine components develop wear after several years of operation, oil consumption becomes an important factor due to the amount of oil leaking past oil control rings and mixing with the air/fuel mixture in the combustion chamber and burning as part of the combustion process. The present invention provides a new and novel means of control oil along the cylinder walls, while incorporating a piston shape that facilitates heat dissipation, reduces thermal expansion and reduces contact interfaces between the piston and cylinder.
In light of the prior art and the given disclosure, it is submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. 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.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | Disclosed is a low drag piston for a reciprocating engine that comprises a piston head that reduces mechanical and viscous friction while improving oil lubrication and thermal load dissipation throughout the piston stroke. The piston comprises a cylindrical crown and lower skirt area such that these elements are the only surfaces in contact with the cylinder walls and support a plurality of piston rings, while the interior skirt region is recessed inward in a concave shape to reduce drag, friction and thermal expansion interferences. An additional oil control ring increases oil outflow to further reduce friction and drag, while the pin boss that holds the connection between the piston head and the connecting rods is recessed inward within the inwardly concave central portion. | 5 |
BACKGROUND OF THE INVENTION
Various and numerous plastic polymer (resin) materials are known which are reinforced with carbon fibers. Such composite materials are desirable where good strength properties and lightweight are required, for example in the manufacture of airframes.
Unfortunately, while initial physical properties of such composites can be very good, such composites are subject to fatigue damage which can lead to catastrophic failure. Such failure cannot, of course, be tolerated in such applications as airframes.
Fiber composites of other materials, such as lead-tin alloys are known, e.g., as described in "The Fracture Mechanisms of Carbon Fiber Reinforced Pb-Sn Composite Material", Chengfu et al., July 1987, 6th International Conference on Composite Materials and 2nd European Conference on Composite Materials (ICCM & ECCM), Vol. 2, 2.183-2.188, Elsevier Applied Science Publishers Ltd., London, England.
Such composites are nevertheless subject to stress fracture and are of course very dense and are therefore completely unsuitable for use in major structural components of aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a cross-sectional perspective view of a composite of the invention.
FIG. 2 shows a fracture surface after tensile testing of a composite of the invention containing 22.9 wt.% alloy (1.8 vol.% alloy). (a) shows a low magnification image of almost the entire cross-sectional thickness of the composite specimen. (b) shows a high magnification image of the alloy particles in the alloy layer in the middle strip of (a).
FIG. 3 shows a fracture surface after tensile testing of a composite of the invention containing 22.9 wt.% alloy (1.8 vol.% alloy).
FIG. 4 shows a fracture surface after fatigue testing of a composite of the invention containing 32.9 wt.% alloy (4.1 vol.% alloy). (a) shows a part of the alloy layer, which is the middle layer of the composite. (b) shows a part of a fiber layer.
FIG. 5 shows a fracture surface after impact testing of a composite of the invention containing 25 wt.% alloy (5.8 vol.% alloy).
BRIEF DESCRIPTION OF THE INVENTION
It has now been surprisingly discovered that the fatigue resistance of resin-carbon fiber composites can be dramatically improved by incorporating tin alloy into the plastic matrix along with the carbon fibers. The addition of the alloy has been found to surprisingly increase the fatigue life by as much as over 100 times a similar composite which does not incorporate the alloy, while having little or no negative effect upon the strength and modulus of the composite. Also, because the tin alloy comprises from as low as 5 to usually no more than 50 weight percent of the composite, density of the composite may be kept low enough to permit the composite to be used in lightweight applications.
In its most preferred form, tin-lead alloy particles are incorporated into the resin matrix in layers between carbon fiber layers.
In accordance with the invention, there is therefore provided a composite article comprising a resin matrix containing both carbon fibers and a tin alloy. In the preferred embodiment, fiber containing layers within the matrix are separated by alloy containing layers within the matrix.
The invention further includes the method of manufacturing the composite articles by impregnating layers of carbon fibers with a resin to form impregnated sheets, spreading alloy powder between the sheets and compression molding the resulting article at a sufficient temperature and pressure for a sufficient time to melt the alloy and cure the resin.
DETAILED DESCRIPTION OF THE INVENTION
The resin matrix may be either a thermoplastic or thermosetting polymeric material. The polymer is usually an organic polymer but may contain inorganic components, e.g., as in the case of polysiloxanes. Suitable thermoplastic materials may, for example, be linear polyesters, and linear vinyl polymers. Such linear resins usually have molecular weights of from 200,000 to 1,000,000 or higher. Examples of suitable thermosetting resins are cross-linked polyesters, epoxies and melamine-formaldehyde type resins. Such crosslinked resins have what may be referred to as infinite molecular weight. "Cure" as used herein means to crosslink a thermoset resin and to soften and solidify a thermoplastic resin.
The resin, in the case of thermoplastic resins, may be melted and applied over the fibers and alloy. In the case of thermosetting resins, the resin is usually applied in liquid form over the fibers and alloys and then crosslinked to form the composite article. In general, the resin comprises from about 40 to 75 weight percent of the composite.
The carbon fibers may be any suitable carbon fibers, e.g., graphite, and may vary significantly in average diameter and length. The fibers usually have an average diameter of from 0.1 to 100 microns, and preferably from 0.1 to 20 microns. The diameter may commonly be from 1 to 15 microns. The average length of the fiber may vary from about 10 microns, usually from 100 microns, to the length of the article. The preferred fiber has an aspect ratio of at least 4:1 and most preferably is a continuous fiber and thus has a long length relative to the size of the article and may run the entire length of the article.
The tin alloy usually comprises from about 5 to 50 weight percent of the article. The alloy usually contains from about 40 to 100 weight percent tin and from 0 to 60 weight percent lead; however, up to 20 weight percent of other metals such as aluminum, antimony, bismuth, cadmium, copper, gold, indium, lead, mercury, silver, tellurium, and zinc may be present; provided that, the presence of the additional metal does not adversely raise the melting point of the alloy or enter into undesirable reactions during manufacture of the composite or under conditions of use of the composite. Such tin and tin alloys, as described above, are collectively referred to as tin alloys herein.
It is preferred that the alloy melts below the curing temperature of the polymer, so that the compression molding involves the hot pressing of the molten alloy while the polymer cures. We believe that this is partly responsible for the good adhesion between the alloy particles and the polymer matrix. On the other hand, the melting point of the alloy should not be so low that it affects the thermal stability of the composite. Eutectic alloys are often desirable. A tin-lead alloy near the eutectic composition melts just below the curing temperature of suitable resins and is an inexpensive alloy that is widely used as a solder. Therefore, it is well suited for this composite application.
A preferred alloy comprises 60 weight percent tin and 40 weight percent lead.
Even though the tin-lead alloy has a high density, since only a small amount of the alloy is used, the increase in density of the composite is small, e.g., only 20% for an alloy content of 33 wt.% or 4.1 vol.%.
The alloy is usually in particulate form and usually has an average particle size of from 5 to 50 microns.
The preferred composite 10, as shown in FIG. 1, comprises a resin matrix 12 comprising embedded layers of carbon fibers 14 separated by layers of alloy particles 16. The carbon fibers in the fiber layers may be oriented or random. Usually, the alloy particles in the alloy layers are discontinuous, i.e., the particles are generally discrete and only occasionally and randomly touch and are thus not interconnected.
In forming the composite articles of the invention, layers of carbon fibers are impregnated with resin to form impregnated sheets. Alloy powder is then spread upon and sandwiched between the sheets and the article is compression molded at sufficient temperature and pressure for a sufficient time to melt the alloy and cure the resin.
The sufficient temperature is usually from 150° to 300° C., the sufficient pressure is usually from 0.5 to 5 MPa and the sufficient time is usually from 5 to 120 minutes.
The fabrication of the composites of the invention does not involve an additional processing step compared to the fabrication of a conventional carbon fiber composite. This is because the alloy particles just need to be sandwiched by the preimpregnated (prepreg) layers during the lay-up operation. The bonding of the alloy particles and the curing of the polymer resin are achieved in a single step of hot pressing. This also means that the alloy particles may be added at chosen locations in a composite structure during the fabrication of the composite structure. In this way, the beneficial effect of the alloy may be realized with a minimum increase in the overall density of the composite structure.
The following examples illustrate but are not intended to limit the present invention.
EXAMPLES
The carbon fibers used in these examples were graphite, undirectional, continuous, unsized and were in the form of 12,000 (12K)-filament-count tows. They were obtained from Hercules Inc. (Magnamite Graphite Fiber, Type IM6™).
The tin-lead alloy was powdered solder of composition 60 wt.% Sn, 40 wt.% Pb, obtained from Taracorp Industries Inc. The average particle size was about 325 mesh (21-25 μm).
Epoxy was used as the binder or matrix. The epoxy was obtained from Dexter Hysol (RE2039, HD3475™).
The carbon fibers wound on a cylindrical mold, were impregnated with the epoxy resin and cut to form preimpregnated oriented graphite fiber containing sheets of a size of about 10×18 cms., which were then placed in a pressure mold together with a weighed quantity of alloy powder between all prepreg sheets. Multiple alternating layers of the preimpregnated sheets and 5 g of alloy powder were used, such that the outermost layers were fiber layers. Typical thicknesses of a fiber layer and an alloy layer were respectively 0.36 and 0.18 mm. An alloy layer typically contained 18 vol.% alloy, as calculated from density and layer thickness data. However, the alloy distribution was not uniform throughout the entire thickness of the alloy layer. The alloy amounted up to 37 wt.% of the composite, which was fabricated by compression molding at 185°-200° C. and 1 MPa for 30 min. The heating allowed the alloy to melt while the epoxy cured.
Fatigue testing
Tension-tension fatigue tests were performed on flat un-notched specimens with tension along the fiber direction and at a stress ratio of 0.5 and a frequency of 5 Hz. Each specimen consisted of three layers, namely the two exterior fiber layers and the interior alloy layer. A hydraulic Materials Testing System (MTS) was used. The fatigue life was taken as the number of cycles at which complete fracture took place. It is shown in Table 1 for each test performed. For a similar value of the mean stress, the increase of alloy content from 0 to 33 wt.% increased the fatigue life by over 100 times.
Also shown in Table 1 is the density of each composite. The alloy addition increased the density of the composite. The alloy volume fraction was calculated from the density of the composite compared to that of the composite containing no alloy.
Tensile testing
Tensile testing was carried out using a hydraulic MTS system, with the force parallel to the fibers. The strain was measured by using an extensometer, with a gage length of 1.0 in (2.5 cm). Each specimen consisted of three layers, namely the two exterior fiber layers and the interior alloy layer.
All tensile stress-strain curves were in the form of a straight line all the way to the fracture point. Table 2 shows the tensile strength, modulus and ductility (elongation) for composites containing up to 37 wt.% alloy. Five specimens of each composition were tested. The tensile strength, modulus and ductility were not much affected by the alloy addition. However, the data suggest some slight increases in strength and modulus by the addition of 22.9 or 25.2 wt.% alloy. It is significant that the alloy addition did not degrade the tensile strength or modulus, even though the alloy particles were intrinsically weak. This indicates very good bonding between the alloy particles and the carbon fibers.
Compressive testing
Compressive testing was carried out using a hydraulic MTS system, with the force parallel and perpendicular to the fibers. The strain was measured by the displacement.
For tests with the force parallel to the fibers, each specimen consisted of seven alternating layers, i.e., four fiber layer and three alloy layers. The exposed specimen size was 0.7 ×0.5×0.065 in (1.8×1.3×0.17 cm), so the gage length was 0.7 in (1.8 cm) and the cross-sectional area was 0.032 in 2 (0.21 cm 2 ). Four specimens were tested for each composition.
For tests with the force perpendicular to the fibers, each specimen consisted of 23 alternating layers, i.e., 12 fiber layers and 11 alloy layers. The exposed specimen size was 0.56×0.56×0.25 in (1.4×1.4×0.64 cm), so the gage length was 0.25 in (0.64 cm) and the cross-sectional area was 0.31 in 2 (2.0 cm 2 ). Six specimens were tested for each composition.
All compressive stress-strain curves were in the form of a straight line all the way to the fracture point. Table 3 shows the compressive strength and modulus. The compressive strength and modulus in both force directions were not much affected by the alloy addition. The data suggest some slight decreases in strength and modulus in the direction perpendicular to the fibers due to the alloy addition, but, due to the scatter in the data, the decreases are not significant. On the other hand, it is significant that the alloy addition did not degrade the compressive strength or modulus in the direction parallel to the fibers, as delamination is the cause of failure in this force direction. Hence, this indicates that the alloy addition does not degrade the interlaminar bond strength.
Flexural testing
Flexural testing was performed by three-point bending, with a span of 2.38 in (6.05 cm). A hydraulic MTS system was used.
Table 4 shows the flexural strength and modulus. Each specimen consisted of eleven alternating layers, i.e., six fiber layers and five alloy layers. Seven specimens of each composition were tested. The flexural strength and modulus were not negatively affected by the alloy addition. The data even suggest some slight increases in the flexural strength and modulus due to the alloy addition.
Impact testing
The toughness was investigated by using a Tinius Olsen Model 66 Charpy-Izod Impact Test Machine (ASTM D256). The specimens were notched, with size 0.5×2.5×0.065 in (1.3×6.4×0.17 cm). The notched impact strength is shown in Table 5 for two compositions. Each specimen consisted of seven alternating layers, i.e., four fiber layers and three alloy layers. Seven specimens were tested for each composition. The notched impact strength was not negatively affected by the alloy addition. The data in fact suggest some increase of the notched impact strength due to the alloy addition.
Damping testing
Damping was tested by using a Bruel and Kjaer apparatus. The loss factors were measured by the resonance peak half-width value method. The widths of the flexural resonance frequencies in a cantilever beam sample at 3 dB from the peak amplitudes were measured and the loss factors were calculated from 3 dB widths (f n ) divided by resonance frequencies (f n ). The samples were of dimensions 7.0×0.5×0.03 in (free length=6.25 in rather than 7.0 in). An impulse force was applied to one of the two largest faces of the sample near its end by using a human finger. Each specimen consisted of three alternating layers, i.e., two fiber layers and one alloy layer. At least five readings were taken for each specimen.
Table 6 shows the loss factors obtained. The loss factor was not affected by the alloy addition.
Electrical resistivity testing
The electrical resistivity was measured by using the fourprobe method. Electrical contacts were made with silver paint. Each specimen consisted of three layers, i.e., two fiber layers and one alloy layer. At least ten readings were taken for each specimen. Table 7 shows the results. The electrical resistivity increased with increasing alloy content. This is consistent with the discontinuous nature of the alloy particles. Although the alloy melted during composite fabrication, the particles remained discontinuous. This conclusion is also supported by scanning electron microscopic observation.
Electromagnetic interference (EMI) shielding effectiveness
Metal particles are frequently added to polymer-matrix composites for the purpose of increasing the EMI shielding effectiveness, which was therefore measured.
The coaxial cable method was used. The set-up consisted of a shielding effectiveness tester (Elgal SET 29A™), which was connected with a coaxial cable to a sweep signal generator (10-2500 MHz) (Wavetek 2002ATM) on one side and on the other side to a variable attenuator, 0-50 dB, ±0.1 dB (Alfred Electronics E101™), followed by a crystal detector (Hewlett Packard 423A™) and then by a DC voltmeter. The crystal detector served to convert the signal to a voltage.
Each specimen was in the form of an annular disc, with an outside diameter of 97.4 mm and an inside diameter of 28.8 mm. Conductive silver paint was applied to the inner surface of the center hole of the specimen and to the flat surfaces of the specimen to a width of 5.1 mm from the inner rim of the annular disc, in order to allow a continuous metallic contact to be made between the sample and the steel tubing in the center of the tester. Moreover, silver paint was applied to the flat surfaces of the specimen to a width of 3.7 mm from the outer rim of the annular disc in order to allow a continuous metallic contact to be made between the sample and the steel chamber of the tester.
In the measurement, after inserting the specimen in the tester, the variable attenuator was set to zero and the voltmeter was read. Then the specimen was removed from the tester and the variable attenuator was adjusted until the voltmeter had the same value as the case with the specimen in the tester. The reading of the adjusted attenuator gave the attenuation, which described the shielding effectiveness.
Each specimen consisted of three layers, i.e., two fiber layers and one alloy layer. At least four readings were taken for each specimen at each frequency.
Table 8 shows the results. The shielding effectiveness at each frequency was decreased slightly by the alloy addition. This is consistent with the increased electrical resistivity due to the alloy addition and is also consistent with the fact that continuous carbon fibers are highly effective for shielding.
Scanning electron microscopy
Scanning electron microscopy (SEM) was used to examine the fracture surfaces after various mechanical tests.
FIG. 2 shows the fracture surface after tensile testing of a composite containing 22.9 wt.% alloy (1.8 vol.% alloy). The composite consisted of three layers, i.e., two fiber layers and one alloy layer. The density of the composite was 1.589 g/cm 3 . FIG. 2(a) shows a low magnification image of almost the entire cross-sectional thickness of the specimen. The brighter strip which stretches horizontally near the center of the photograph is the layer containing the alloy particles, which appear as round particles of diameter much larger than the fiber diameter. The tips of fibers were observed elsewhere throughout the photograph. The alloy particles are shown more clearly in the high magnification image in FIG. 2(b). The particles were partially covered by the polymer matrix, indicating good adhesion between the alloy particles and the polymer matrix. The average particle size was 23 μm. The pattern on the surface of each alloy particle is associated with the eutectic structure of the alloy.
The fracture mechanism is revealed more clearly by FIG. 3, which is the tensile fracture surface of the same composite as FIG. 2. Fracture began in the matrix. Some fiber pull-out occurred. Some of the alloy particles fell out from the fracture surface.
FIG. 4 shows the fracture surface after fatigue failure of a composite containing 32.9 wt.% alloy (4.1 vol.% alloy). The density was 1.753 g/cm 3 . FIG. 4(a) shows a part of the middle layer, i.e., the layer containing alloy particles. The alloy particles were held together by the polymer matrix. FIG. 4(b) shows a region containing fibers. The polymer matrix between the fibers cracked and then the cracks enlarged. Eventually, the fibers broke. The three large round features along a horizontal line near the center of FIG. 4(b) are the tips of the fibers.
FIG. 5 shows the fracture surface after impact testing. The composite contained 25 wt.% alloy (5.8 vol.% alloy) and consisted of seven layers, i.e., four fiber layers and three alloy layers. The density was 1.749 g/cm 3 . Both the matrix and the fibers were broken.
These examples demonstrate that the addition of tin-lead (60 wt.% Sn) alloy particles (about 21-25 μm in diameter) between continuous carbon fiber layers in an epoxy-matrix composite can improve the fatigue life by over 100 times. The alloy amounted up to 37 wt.% (7.2 vol.%) of the composite. For a composite containing 33 wt.% (4.1 vol.%) alloy, the fatigue life was 6.8×10 5 cycles at a mean stress of 510 MPa, a load ratio of 0.5 and a frequency of 5 Hz, compared to a corresponding life of 4.0×10 3 cycles for a composite containing no alloy and tested at a mean stress of 530 MPa. This amount of alloy increased the density of the composite from 1.46 to 1.75 g/cm 3 . In general, the alloy condition has little negative and often some positive effect on the tensile strength, tensile modulus, compressive strength, and compressive modulus (with the compressive force parallel and perpendicular to the fibers), but it increased the electrical resistivity.
TABLE 1______________________________________Fatigue lifeWt. % Vol. % Density Mean stress Fatigue lifealloy alloy (g/cm.sup.3) (MPa) (cycles)______________________________________0 0 1.461 530 4.0 × 10.sup.329.6 2.1 1.609 568 3.8 × 10.sup.433 4.1 1.753 510 6.8 × 10.sup.50 0 1.461 639 1.0 × 10.sup.233 4.1 1.753 643 1.2 × 10.sup.423 1.8 1.589 564 >4.7 × 10.sup.518.2 2.0 1.599 405 9.5 × 10.sup.515.4 1.2 1.545 474 >4.0 × 10.sup.5______________________________________
TABLE 2______________________________________Tensile test resultsWt. % Vol. % Density Strength Modulus Ductilityalloy alloy (g/cm.sup.3) (MPa) (GPa) (%)______________________________________0 0 1.461 867 (±129) 69 (±35) 1.022.9 1.8 1.589 914 (±190) 79 (±14) 1.225.2 2.7 1.650 961 (±82) 77 (±8) 1.336.9 7.2 1.970 729 (±113) 70 (±10) 1.3______________________________________
TABLE 3______________________________________Compressive test resultsForce Wt. % Vol. % Density Strength Modulusdirection alloy alloy (g/cm.sup.3) (MPa) (GPa)______________________________________Parallel to 0 0 1.334 183 ± 23 1.2 ± 0.1fibers 31.7 4.2 1.636 173 ± 35 1.2 ± 0.4Perpendicular 0 0 1.281 131 ± 3 5.7 ± 1.5to fibers 26 5.1 1.647 129 ± 1 4.1 ± 1______________________________________
TABLE 4______________________________________Flexural test resultsWt. % Vol. % Density Strength Modulusalloy alloy (g/cm.sup.3) (GPa) (MPa)______________________________________0 0 1.363 7.9 ± 1.3 240 ± 3826.8 5.4 1.751 9.1 ± 0.8 295 ± 39______________________________________
TABLE 5______________________________________Impact test resultsWt. % Vol. % Density Notched impact strengthalloy alloy (g/cm.sup.3) (ft · lb/in.sup.2)______________________________________0 0 1.334 35 (±4)25 5.8 1.749 41 (±6)______________________________________
TABLE 6______________________________________Damping test resultsWt. % Vol. % Densityalloy alloy (g/cm.sup.3) Loss factor______________________________________0 0 1.461 0.0233 4.1 1.753 0.02______________________________________
TABLE 7______________________________________Electrical resistivityWt. % Vol. % Density Electrical resistivityalloy alloy (g/cm.sup.3) (Ω · cm)______________________________________0 0 1.460 4.1 × 10.sup.-322.9 1.8 1.589 1.0 × 10.sup.-229.6 2.1 1.609 1.3 × 10.sup.-2______________________________________
TABLE 8______________________________________EMI shielding effectivenessWt. Vol. Shielding% % Density Thickness Frequency effectivenessalloy alloy (g/cm.sup.3) (cm) (GHz) (dB)______________________________________0 0 1.332 0.08 1.0 16.0 1.3 15.3 1.5 16.2 2.3 20.234.2 1.4 1.436 0.10 1.0 13.6 1.3 13.4 1.5 15.5 2.3 18.0______________________________________ | A composite article comprising a resin matrix containing both carbon fibers and a tin alloy. In the preferred embodiment, fiber containing layers within the matrix are separated by alloy containing layers within the matrix.
The invention further includes the method of manufacturing the composite articles by impregnating layers of carbon fibers with a resin to form impregnated sheets, spreading alloy powder between the sheets and compression molding the resulting article at a sufficient temperature and pressure for a sufficient time to melt the alloy and cure the resin. | 8 |
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a comber having a nipper head with detaching rolls, and having a half lap with a fiber tuft adjacent needles of the half lap.
At a comber during one combing cycle, in other words during a complete forward/backward movement of the nipper, the half-lap with its needles arranged in a segment of a circle accomplishes one complete revolution about its axis. If the comber is operating for example at 300 nips per minute, the half lap will likewise be rotating 300 times a minute and, per rotation, it will comb through the fiber web protruding from the nipper once. In the most inward position, this being the greatest distance of the nipper from the detaching rolls, the needles on the half-lap are at their closest to the nipper. In the most outward position of the nipper, at the shortest distance (detachment length) of the nipper from the detaching roll, the comb cylinder has rotated by about half a rotation, and its needles are positioned on the side turned away from the nipper. To comb the fiber web there is only about one-fifth of the machine cycle available, which means that the sector angle, through which the half-flap carries needles, is determined, and an increase of the combing effect could be achieved only by enlarging the segment radius. Because the comber is required to fulfil certain geometrical conditions in function of the staple length of the fiber material, the radius of the half-lap cannot be enlarged at will, as otherwise these elements would collide.
Persons familiar with the art are aware that only an intimate and multiple contact of the individual fibers with the combing elements lead to a satisfactory combing result, and also that a half-lap carrying needles which gradually become finer will likewise improve the combing result. Accordingly, every effort is to be made to achieve a large surface area for an active half-lap, in order to attain optimum combing quality.
In addition to the performance limitations imposed by the design features referred to above, there is a further disadvantage in that the needle arrangement only passes the brush once per combing cycle, with the result that, at high production rates and in particular with a narrow needle arrangement, the needles cannot be kept sufficiently clean and their effect deteriorates. To avoid this disadvantage, in some cases the machine is periodically switched to a slower speed, which at best incurs loss of production, but more often results in quality fluctuations.
SUMMARY OF THE INVENTION
The invention is accordingly based on the task of increasing the comb effect and to homogenize the combing process.
According to the invention, this task is resolved by constructing a comber having a nipper head with detaching rolls, and having a half lap with a fiber tuft adjacent needles of the half lap; and wherein the half lap is rotated plural times during one cycle.
To the extent that, based on the invention, the revolution speed of the comb cylinder increases during a combing cycle, the cleaning effect on the needles is improved, and hence also the combing effect and homogeneity of the combing process are improved. These effects can be increased still further because the active surface of the needle arrangement can be increased within broad limits.
As a result, the half-lap remains continuously clean and operational machinery stops for half-lap cleaning are unnecessary. This not only results in higher machine performance, but also in uniform and maximum quality of a combing cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained by examples in the schematic drawings appended. These show:
FIG. 1 A cross-section of a comber machine,
FIG. 2 The same drawing as FIG. 1, showing the movement sequence of the essential elements during a combing cycle, and
FIG. 3 A cross-section of a further embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the principle layout of a comber machine similar to that described in detail in U.S. Pat. No. 3,479,699 (equivalent to Swiss Patent 485 873). In the machine frame 1, a nipper head 3 with a clamping shackle 8 is secured in a rotatable manner to a nipper shaft 2, operating with a half-lap 4 having a needle-segment 5. The nipper head 3 operates in conjunction with detaching rolls 6. A web 7 which is to be combed is fed continuously to the nipper head 3 from a further lap (not shown) which is located on a continuously driven pair of delivery-rolls, likewise not shown. The leading edge of the web, referred to as a fiber tuft 10, is pieced to the already combed tuft 11, which is held by the detaching rolls 6, the latter moving backward/forward in a step-and-repeat fashion (referred to as pilgrims step). The tuft 10 is passed on and separated from the following web and pieced to the tuft 11. The needle segment 5 is cleaned from the noil combed out of the fiber tuft 10 by means of a brush roller 12, which rotates in the opposite direction at a larger circumferential speed than the half-lap 4. The nipper head 3 features a nipper plate 13, which is coupled to the nipper shaft 2 and a nipper knife 14, which is rotatably mounted.
The nipper plate 13 consists essentially of a nipper plate arm 15 and a nipper plate blade (cushion plate) 16 secured to it. The nipper knife 14 is rotatably mounted on a lateral swivelling journal 17 on the nipper plate arm 15. In addition to this, a feed roller 18 for the web 7 is mounted on bearings on the nipper plate 13, the latter converting the continuous lap feed into a discontinuous feed of the shaft 10. The intermittent drive of the feed roller 18 takes place in the rhythm of the nipper head movement, by means of a pawl drive, not shown here but described in detail in the aforementioned U.S. Pat. No. 3,479,699.
The nipper knife 14 consists essentially of a nipper knife arm 20 linked to the swivel journal 17, and a nipper knife plate 21 (also referred to as the knife blade), secured to the arm 20 as well as a lever 9 secured to this. In addition, the nipper knife 14 is provided with an adjustable penetrating comb 19, which holds back those fibers from the fiber tuft 10 which do not have the length of the tear-off spacing (separation), preventing them from being drawn into the detaching rolls 6.
The nipper knife plate 21 can be swivelled against the nipper plate blade 16 and away from it in the movement rhythm of the nipper head 3, in such a way that the nipper head 3 is closed in the rear end position (as shown in FIG. 1, with the fiber wad 10 clamped tight), or opened in the front end position (in which the knife plate blade 16 has approached the clamping point of the detaching rolls 6 to the distance of the detachment length). The synchronization of the movement of the nipper knife 14 with the movement of the nipper head 3 is effected by means of a linkage 22, the ends of which are attached to the machinery frame 1 on the one hand and, on the other, to the lever 9 which is secured to the nipper knife arm 20.
The detaching rolls 6 comprise two pairs of detaching rolls 6', 6", each of which has a lower, driven detaching roll 23 and an upper roll 24. The detaching rolls can also be formed by only one pair of detaching rollers 6". Their periodic backwards and forwards rotation (as already mentioned) causes the combed tuft 11 to be moved in the direction of the arrow 25 and, in the return movement, causes a connection to be established with the combed fiber tuft 10, fed in from the nipper head. Beneath the lower detaching roll 23 of the pair of rollers 6" is a baffle plate 26, running tangentially to the roll 23 and then parallel at a distance from a second plate 28, which leaves a gap 27 between the two plates 26 and 28 to form a flow channel 29 for an air flow entering through the gap 27. The strength of the air flow entering through the gap 27, can be regulated, for example, by means of a choke device 30 which at high operating speeds, brings the fiber tuft 10 in a controllable manner with the tailing end of the combed tuft 11 in contact on the lower detaching roll 27. This leads to a uniform merger of combed tuft and fiber tuft. In simpler embodiments, the presence of the baffle plate 26 is sufficient to screen the detaching rolls 6 against the air turbulence caused by the half-lap 4 as a result of its increased speed of rotation.
The sector angle α of the needle segment 5 and the radius of the half-lap 4 are dimensioned in such a way that all the needles of the needle segment 5 in the area of the rear final position of the nipper head 3 (as shown in FIG. 1) penetrate through the fiber tuft 10 once. The drive for the comber machine is provided by a motor 31, which drives a timing shaft 33 by means of a reduction gear 32. With each revolution of the timing shaft 33, the machine completes one combing cycle. A crankpin 34, which rotates with the timing shaft 33, is connected in terms of the drive mechanism by a crankshaft 35 with a swivel journal 36 to a lever 36'. The lever 36' is secured to the nipper shaft 2, so that the nipper head 3, during a revolution of the timing shaft 33, is swivelled once out of the rear end position into the front end position and back.
Likewise in cyclical synchronism with the timing shaft 33, the lower detaching rolls 23 are driven by means of a step-and-repeat gear arrangement 37, which is already known, with the result that the movement of the gear arrangement 37 backwards and forwards during a combing cycle takes place in the same manner as with known combers.
In accordance with the invention, the half-lap 4 completes not only one full rotation during one rotation of the timing shaft 33, but two or more. For this purpose, a pinion 38 is located on the timing shaft 33, which engages with a pinion 39, which in turn drives the half-lap 4. The transmission ratio of the timing shaft 33 to the half-lap 4 is 1 :N, where N is a whole number, but at least two. The pinion 39 also drives another pinion 40, with the transmission ratio between these pinions 39, 40 being selected in such a way that the circumferential speed of the brush roller 12 is greater than that of the half-lap 4, the brush roller 12 rotating in the opposite direction to the half-lap 4.
In a preferred embodiment of the comber, the half-lap 4 rotates twice during one revolution of the timing shaft 33, in other words during one combing cycle. The mode of operation is described below, based on FIG. 2. To illustrate this more clearly, one machine cycle or one revolution of the timing shaft 33 is subdivided into twenty step increments, designated hereinafter as Index 1 to 20.
During one combing cycle, the nipper head 3 swings around the nipper axis 2, out of the rear end position, via a path which comes very close to the circumferential circle of the half-lap 4, into the front end position, and back. During the swing, the leading edge of the nipper plate 16 moves on an arc 41. During the outward movement (Indices 0 to 12), the nipper head 3 moves away from the half-lap 4, and during the return movement (Indices 12 to 20), the nipper head 3 approaches the half-lap 4 again. During this return movement (Indices 12 to 20) of the nipper head 3, that phase of the combing cycle begins (Index 181/2) during which the needle segment 5 engages in the fiber tuft 10, and ends (after the reversal of movement of the nipper head 31) with Index 31/2 of the next combing cycle. Because the half-lap 4 carries out two revolutions during one combing cycle, the needle segment 5 again moves beneath the nipper head 3, during a second phase (Index 81/2 to 131/2) and during which the nipper head 3 adopts a more distant position from the half-lap 4, without a combing process taking place. It is during this period of time that the merging of the fiber tuft 10 with the combed tuft 11 takes place. By doubling the number of rotations of the half-lap 4, the time window delimited by Indices 181/2 to 31/2 remains unchanged. However, the doubled speed causes the effective length of the needle-segment 5 to be doubled with a given comb cylinder diameter. The increase and homogenization of the combing effect, which the invention seeks to achieve, is attained. The limits of this time window are essentially fixed. As a result, the active circumferential length of the needle segment 5, obtained with a whole-number multiplication of the rotational speed of the half-lap 4 (and with the radius remaining the same), can be increased in the same proportion without the half-lap 4 colliding with the nipper head 3, the detaching rolls 23, or the baffle plate 26.
The half-lap 4, rotating at greater speed, produces air turbulence in the area of the detaching rolls 6, which might impede a the trouble-free merging of the fiber tuft 10 with the combed top end 11. To control such turbulence, if necessary, the choke 30 is used to change the air flow in the gap 27 until the fiber tuft and the end of the combed top meet one another at a precisely defined position.
The invention allows for the following advantages to be obtained: It is possible to comb out heavy wads. The fiber tuft is combed through during a combing cycle by approximately double the number of comb elements. More short fibers, impurities, and neps are separated out. The needle segment remains clean, because it is cleaned by the brush roller at least twice per combing cycle. In addition to this, because of the longer needle segment, the first row of needles can be arranged less densely, without inhibiting the combing effect. As a result, no air pressure wave is incurred in front of the needle segment with the half-lap running. Such a wave would push the fiber tuft away and raise it above the needle segment, would impair the combing effect of the needle segment, and might render the combing effect impossible.
Alternatively, the nipper head 3 can be displaced backwards and forwards, between its front and rear end positions, instead of on a bow-shaped path, on another curve-shaped or straight track.
Further, as FIG. 3 shows, the invention can also be applied on comber machines as described, for example, in GB-Patent 1 207 441. With these comber machines, the nipper head 3 can only be moved up and down during a combing cycle in the direction of the double arrow 42. The relative movement between the nipper head 3 and the detaching roll 6 is dependent exclusively on the detaching rolls 6, which for this purpose are mounted on bearings on an oscillating link 44, capable of a swivelling movement about an axis 43. The link 44 is moved once during a combing cycle out of its rear end position into the front end position and back again, moved by means of a drive unit which is not shown, as indicated by the two arrows. | A comber has a nipper head (3), detaching rolls (6), and half-lap (4), wherein, during a combing cycle, the nipper head (3) and the detaching rolls (6) are moved by a drive system (31 to 40) out of a rear end position relative to one another into a front end position and back again. The detaching rolls (6) are driven in a pull-off direction (25) of a combed tuft (11). The half-lap (4) is also driven. The nipper head (3) comes within an area of action of a needle segment (5) of the half-lap (4) during a section of the combing cycle. To increase performance, provision is made for the drive system (31 to 40) to rotate the half-lap (4) during a combing cycle by an integral number of rotations, at least twice. The length of the needle segment (5) is extended in the direction of rotation in accordance with a higher rotational speed. | 3 |
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit under 35 U.S.C. §119(e) of U.S. provisional application Ser. No. 60/771,073, filed Feb. 7, 2006, the disclosure of which is hereby expressly incorporated by reference in its entirety and is hereby expressly made a portion of this application.
FIELD OF THE INVENTION
A method is provided for making zeolite-films more hydrophobic, it also relates to the field of UV-cure. The methods are related to the field of semiconductor processing, and to membranes and membrane fabrication. More specifically, a method is provided for improving the properties of pure-silica zeolites (silicalites) and/or zeolite-like materials to be used as dielectric material in between interconnects in semiconductor devices.
BACKGROUND OF THE INVENTION
Pure-silica Zeolites as porous materials have found various commercial uses in the catalysis, adsorption, and ion exchange industries. Beside that, pure-silica zeolites find more and more applications in other areas because of their superior mechanical properties and porosity. In combination with their porous character leading towards a material with a low-dielectric constant, pure-silica zeolites are a strong candidate for a replacement low-dielectric constant (low-k) material for next-generation microprocessors. In order to survive the chemical-mechanical processing steps, the semiconductor industry generally acknowledges a minimum threshold value of 6 GPa (Young's Modulus) for these materials.
Pure silica zeolites have been proposed as low dielectric constant materials for interconnects the first time by Yan et al. (U.S. Pat. No. 6,630,696). The advantage of using pure-silica-zeolites as low-k material is the combination of crystallinity and porosity such that superior mechanical properties and high porosity can be obtained. The final properties can be tuned by using e.g. different crystalline structure (MFI, BEA, MEL . . . ), by tuning the crystalline/amorphous ratio in the synthesis of the films or by adding porogens to the pure-silica zeolite suspension. Typically, pure-silica zeolites have k values below 2.7.
A main showstopper however for the actual use of pure-silica zeolite materials as low-k films in interconnects is their hydrophilicity (contact angle with H 2 O typically lower than 20 degrees) which is a main issue in low-k dielectrics. The adsorption of moisture within the inner pores of the zeolites can results in a significant increase of the dielectric constant because water has a very high k value (k=80). Hence, it is important to make the zeolites material very hydrophobic to maintain a low-k value.
Post-deposition treatments were proposed in prior art to increase the hydrophobicity of a zeolites film. For example, vapor-phase silylation using chlorotrimethylsilane or hexamethyldisilazane to increase the hydrophobicity of a zeolite film. Since the pore size of silica zeolites is very small, the chlorotrimethylsilane molecules may encounter diffusion limitations and hence difficulties to access the silanol groups inside the zeolites micropores leading to limited increase in hydrophobization.
Dattelbaum et al. (J. Phys. Chem. B, 109 (2005) pp 14551) used a UV treatment to remove the organic template in a zeolites film after depositing said zeolite film, however no organic functionalization and hence no improvement is seen in the hydrophobicity of the zeolite film because only a photochemical decomposition and desorption of the organic material is performed.
Li et al. (Chem. Mater. 2005, 17, 1851-1854) proposes an organic functionalization of the zeolites crystals (and amorphous silica) during the synthesis of the zeolite nanoparticle suspension (prior to spinning). However the final zeolites film obtained after incorporation of said organic molecules to the silica matrix has a lower thermal stability and the increase in hydrophobicity is rather limited.
As a conclusion there is still a need for an efficient method that increases the hydrophobicity of a zeolite film without altering characteristics such as thermal stability and mechanical strength.
SUMMARY OF THE INVENTION
A method is disclosed for hydrophobization of pure-silica zeolite comprising films or in other words increasing the hydrophobicity of said silica-zeolite materials.
More specifically said method comprises the step of exposing the silica-zeolite film to UV light (also referred to as UV curing) in combination with thermal activation. The use of thermal activation during the UV treatment (exposure) is a key-factor in the preferred embodiments to realize organic functionalization, i.e., the photochemical reaction between the organic species and the silica matrix.
The UV treatment is preferably performed after depositing a silica-zeolite layer onto a substrate (support).
Said depositing step is preferably a spin-coating process but alternative processes such as in-situ crystallization, dip coating can be used.
After depositing a silica-zeolite film onto the substrate, a drying step can be performed. If a drying step is performed, said drying step is preferably performed at around 80° C. (e.g. for a few hours) but it should not totally remove the organics.
In a preferred embodiment, no further thermal treatment (e.g. additional bake) is needed after performing the drying step. The absence of a further thermal treatment to remove the organic template is unusual and in contrast to current state of the art methods. In the preferred embodiments it is recommended not to do a pre-UV thermal step such as an additional bake such that an optimal homogeneity is obtained and absence of cracks is seen.
In an alternative embodiment, there can be an additional heating or bake step after the drying step to remove part of the (organic) template present in the silica-zeolite layer but special care needs to be taken during said bake step to avoid total removal of the organic template such that organic functionalization during subsequent UV treatment still can take place. Said short bake step can be for example at approximately 300° C.
The UV exposure is preferably performed at low wavelengths, more preferred at wavelengths lower than 300 nm e.g. at wavelengths around 250 nm, more specifically in the range of 170 nm up to 250 nm.
The UV light exposure must be combined with a thermal activation. This means that the sample must be kept at a temperature preferably around 425° C. during the UV light exposure. This ensures good efficiency of the UV treatment.
If a thermal bake (using for example a bake temperature of around 300° C.) was performed prior to the UV treatment, the temperature in the tool during the UV light exposure is preferably higher, most preferred around 400° C., for example 425° C.
Said UV cure is preferably performed after the film deposition. If UV cure is performed after a partial removal of the organic template by means of thermal treatment, the final homogeneity or crack presence will not be optimal.
Using UV-curing, the O—H bond in the chemically bonded silanol groups (Si—OH) would be drastically decreased due to the formation of Si—O—Si cross-linking bridges, Si—CH 3 and/or Si—O—CH 3 .
By using UV exposure part of the carbon present in the organic template is kept and found back linked to the silica matrix in the form of Si—CH 3 and/or Si—O—CH 3 functional groups, known to be effective hydrophobic groups.
The combination of removing the silanol groups and creating Si—O—Si, Si—CH 3 and/or Si—O—CH 3 groups will lead to a significant improvement in hydrophobicity. The lowest silanol content after UV-cure is found for spin-on zeolites with higher crystallinity ratio, that is, when a longer crystallization time is performed to obtain the pure-silica zeolite suspension.
To investigate the improvement in hydrophobicity of the silica-zeolite films contact angle measurements, preferably performed with a polar solvent such as H 2 O, can be used. The results of said contact angle measurements (with water) indicate an improvement going from approximately 5 degrees (reference, almost completely wettable) up to higher than 100 degrees (typically 120 deg) after using the UV treatment of the preferred embodiments.
The increase of hydrophobicity is further related to large reduction of trapped physisorbed moisture, said moisture preferably being attracted towards chemically bonded silanol groups.
Furthermore, the enhancement of Si—O—Si cross-linking observed by FTIR will increase the final mechanical properties of the zeolites film.
The efficiency of the UV treatment of the preferred embodiments is dependent on the degree of crystallinity of the silica-zeolite film used.
Adding organic molecules to the zeolite film before UV light and temperature exposure, for example adding methyltrimethoxysilane to the synthesis solution, may further increase the organic functionalization and consequent hydrophobization.
Also provided is use of UV-treated silica-zeolites (with improved hydrophobicity) as low-k dielectric materials in between interconnect structures of a semiconductor device.
Also provided is use of UV-treated silica-zeolites (with improved hydrophobicity) as membranes.
Preferably, in a first aspect, the method for improving the hydrophobicity, functionalization, homogeneity and avoiding cracks and delamination of a zeolite film comprises the steps of forming a zeolite film on a support, wherein said zeolite film is derived from a zeolite synthesis composition comprising a silica source and an organic template; and subjecting said zeolite film to, substantially simultaneously, ultraviolet irradiation and thermal activation.
In an embodiment of the first aspect, said zeolite film is formed on said support by an in-situ crystallization process.
In an embodiment of the first aspect, said zeolite film is formed on said substrate by a spin-on process.
In an embodiment of the first aspect, forming a zeolite film on a support comprises depositing a suspension of zeolite nanocrystals having an average particle size of from about 50 nm to about 70 nm on said support.
In an embodiment of the first aspect, said suspension of zeolite nanocrystals further comprises at least one of smaller silica nanoparticles and clusters of smaller silica nanoparticles.
In an embodiment of the first aspect, said zeolite film comprises at least one zeolite selected from the group consisting of MFI zeolite, MEL zeolite, and BEA zeolite.
In an embodiment of the first aspect, said zeolite film is a pure-silica-zeolite film.
In an embodiment of the first aspect, said support is selected from the group consisting of a silicon wafer, a polymeric support, a porous alumina support, and a ceramic support.
In an embodiment of the first aspect, said silica source comprises an organic silica, for example, tetraethyl orthosilicate, tetramethyl orthosilicate, or mixtures thereof.
In an embodiment of the first aspect, said silica source comprises an inorganic silica, for example, fumed silica, silica gel, colloidal silica, or mixtures thereof.
In an embodiment of the first aspect, said organic template comprises an organic hydroxide, for example, a quaternary ammonium hydroxide such as tetrapropyl-ammonium hydroxide, tetraethylammonium hydroxide, triethyl-n-propyl ammonium hydroxide, benzyl-trimethylammonium hydroxide, or mixtures thereof.
In an embodiment of the first aspect, said thermal activation is conducted at a temperature higher than about 100° C.
In an embodiment of the first aspect, said thermal activation is conducted at a temperature higher than about 150° C.
In an embodiment of the first aspect, said thermal activation is conducted at a temperature higher than about 200° C.
In an embodiment of the first aspect, said thermal activation is conducted at a temperature higher than about 300° C.
In an embodiment of the first aspect, said thermal activation is conducted at a temperature from about 350° C. to about 550° C.
In an embodiment of the first aspect, said thermal activation is conducted at a temperature of about 425° C.
In an embodiment of the first aspect, ultraviolet irradiation is conducted at a wavelength lower than about 300 nm.
In an embodiment of the first aspect, ultraviolet irradiation is conducted at a wavelength lower than about 270 nm.
In an embodiment of the first aspect, ultraviolet irradiation is conducted at a wavelength of from about 170 nm to about 250 nm.
In an embodiment of the first aspect, the method further comprises a step of drying said zeolite film, wherein said drying step is conducted before the step of subjecting said zeolite film to, substantially simultaneously, ultraviolet irradiation and thermal activation.
In a second aspect, a zeolite film is provided that is prepared by a method comprising the steps of forming a zeolite film on a support, wherein said zeolite film is derived from a zeolite synthesis composition comprising a silica source and an organic template; and subjecting said zeolite film to, substantially simultaneously, ultraviolet irradiation and thermal activation.
In an embodiment of the second aspect, the zeolite film functions as a membrane.
In a third aspect, a semiconductor device comprising a zeolite film is provided, wherein the zeolite film is prepared by a method comprising the steps of forming a zeolite film on a support, wherein said zeolite film is derived from a zeolite synthesis composition comprising a silica source and an organic template; and subjecting said zeolite film to, substantially simultaneously, ultraviolet irradiation and thermal activation.
In an embodiment of the third aspect, the zeolite film functions as a low-k material.
BRIEF DESCRIPTION OF THE DRAWINGS
All figures/drawings are intended to illustrate some aspects and embodiments of the present invention. Devices are depicted in a simplified way for reason of clarity. Not all alternatives and options are shown and therefore the invention is not limited to the content of the given drawings. Like numerals are employed to reference like parts in the different figures.
FIG. 1 is a schematic diagram of a spin-on pure-silica-zeolite film.
FIGS. 2A , 2 B and 2 C are Fourier Transform Infrared Spectroscopy (FTIR) spectra illustrating the use of UV light during the thermal removal of the template. As shown in FIG. 2A , the UV light exposure results in almost total removal of OH bonds (seen at 3400-3760 cm −1 ). FIG. 2A also shows a peak at 2970 cm −1 indicating C—H bonds. As shown in FIG. 2B , the UV light exposure results in almost total removal of OH bonds (seen at 980 cm −1 ), the formation of Si—CH 3 bonds (seen at 1277 cm −1 ) and an increase of Si—O—Si bonds (seen at approximately 1070 cm −1 and relates to network bonding having a positive effect on mechanical properties). FIG. 2C shows IR peaks related to the organic functionalization relating to different peaks in range of 800 up to 900 cm −1 .
FIG. 3 illustrates adsorption of toluene in spin-on pure-silica zeolite films exposed to the UV-treatment of the preferred embodiments obtained by ellipsometric porosimetry. Total toluene percentage adsorbed is representative of the total porosity of the films.
FIG. 4 illustrates water adsorption on a silica-zeolite film exposed to the UV-treatment of a preferred embodiment from ellipsometric measurements.
FIG. 5A shows SEM image of a pure-silica zeolite film after removal of the (organic) template by thermal treatment (showing clearly unwanted cracks in the film). FIG. 5B shows SEM image of a pure-silica zeolite film using the UV treatment of a preferred embodiment (no cracks visible).
FIG. 6 shows standard incidence XRD results on a reference spin-on silica-zeolite film. The presence of peaks at 2-Theta around 8, 9 and 23 degrees show the presence of zeolite MFI. However, the low intensity of these peaks suggests that the crystallinity of the film is quite low. The reason is the use of the small silica nanoparticles or clusters as ‘glue holding entities’ of the zeolite nanocrystals and the deficient crystallinity of the zeolite nanocrystals.
FIG. 7A-7C illustrate FTIR charts demonstrating that the lowest silanol content is found after UV-cure for spin-on zeolites with higher crystallinity ratio, that is, when a longer crystallization time is performed to obtain the pure-silica zeolite suspension.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description and examples illustrate various embodiments of the present invention. It will be appreciated that there are numerous variations and modifications of these embodiments that are possible. Accordingly, the descriptions of the various embodiments should not be deemed to limit the scope of the invention, which is defined by the claims.
The term pure-silica zeolites as referred to in this application refers to zeolites having substantially an infinite ratio Si/Al. Said pure-silica zeolites can be made by combining a commercially available silica source with a commercially available organic zeolite-forming structure-directing agent (further referred to as organic template). Examples of pure-silica zeolites are MFI, BEA, MWW, LTA, CHA, MTW) The deposition can be done by in-situ crystallization or by spinning a suspension containing pure-silica-zeolite nanocrystals with ‘glue holding entities’ such as smaller silica nanoparticles (precursors of these nanocrystals).
The term organic “template” as referred to in this application is the structure-directing agent for the silica matrix formation (e.g. tetrapropylammonium). This must be removed to leave the pores empty, and this way decrease the k-value. In the preferred embodiments, the UV-cure in combination with thermal activation, is removing the template in a different way than a thermal calcination promoting organic functionalization
The term hydrophobic as referred to in this application, refers to materials possessing the characteristic to have the opposite response to water interaction compared to hydrophilic materials. Hydrophobic materials (“water hating”) have little or no tendency to adsorb water and water tends to “bead” on their surfaces (i.e., discrete droplets). Hydrophobic materials possess low surface tension values and lack active groups in their surface chemistry for formation of “hydrogen-bonds” with water.
Spin-on pure-silica-zeolite films as referred to in this application are deposited using a silica-zeolite solution in which silica-zeolite nanocrystals (50-70 nm) and smaller silica nanoparticles or clusters are present. The quantity of silica belonging to zeolite nanocrystals is usually low, for example around 30%. The zeolite nanocrystals themselves have a level of crystallinity and a particle size depending on the synthesis conditions (crystallization time, temperature . . . ). There is a trade-off between particle size and level of crystallinity of the nanocrystals. Usually, bigger crystals have better crystallinity but for the homogeneity of the films, small nanocrystals are necessary. The synthesis conditions are preferably optimized to obtain a small crystal size sacrificing crystallinity on them. Because of the non-perfect crystallinity on zeolite nanocrystals there are dangling bonds that contribute to the hydrophilicity of the films. These dangling bonds are reduced by the UV treatment as described in the detailed description proposed.
The smaller silica nanoparticles or clusters present originate from the hydrolysis of the silica source (e.g. TetraEthyl-OrthoSilicate (TEOS)) in the presence of an organic template (e.g. Tetrapropyl-ammoniumhydroxide (TPAOH)), and they are present always in zeolite synthesis prepared from a clear solution (clear solution is the term used in the preparation of zeolites nanocrystals for the clear homogeneous solution where only subcolloidal or discrete particles are present.
There are different theories about the mechanism of formation of the zeolite nanocrystals from a clear solution. For example in the mechanism proposed by Kirschhock and co-authors it is claimed that these small silica nanoparticles have slab shape, crystalline structure and aggregate till forming zeolite nanocrystals. Said smaller silica nanoparticles or clusters, due to their small size, have a high surface area and consequently, high quantity of silanol groups. In spite of having a high surface area, their small size permits to obtain homogeneous films because they are able to fill the voids among the pure-silica-zeolite nanocrystals (50-70 nm). Said smaller nanoparticles work as ‘glue holding entities’ of the zeolite nanocrystals. However, their presence makes these films hydrophilic.
In comparison with the zeolite nanocrystals, the part of the films containing the small silica nanoparticles or clusters have much higher concentration of dangling bonds because of their high internal surface area. Hence, this part of the film could have more active sites for the UV-cure.
A method is provided for improving the hydrophobicity or in other words reducing or substantially eliminating the hydrophilicity of pure-silica-zeolite films.
The reason for the hydrophilicity of said pure-silica-zeolites is the use of crystal grains smaller than 100 nm in combination with the use of zeolite precursors as ‘glue holding entities’ of the zeolite nanocrystals. This leads to a high internal surface area full of Si—OH terminating groups.
The preferred embodiments relate to a new post-deposition method to induce hydrophobization of spin-on silicalite-1 films during the removal of the organic template. The method comprises of a wide-band UltraViolet (UV) irradiation combined with thermal activation. The hydrophobization is obtained because the UV-treatment decreases drastically the quantity of silanols and makes the organic template react with the silica matrix forming hydrophobic Si—CH 3 groups while desorbing. The Si—O—Si bond angle decreases and moreover, the formation of cracks larger than 50 nm is avoided.
The method of the preferred embodiments comprises the step of exposing the silica-zeolite film to UV light and temperature. Said UV treatment is done after the deposition of a silica-zeolite film onto a substrate. Several methods are described in literature to perform the deposition of a silica-zeolite film onto a substrate. Preferred methods are e.g. spin-on or in-situ crystallization.
After the deposition step, the pure-silica-zeolite film can be dried; said drying can be performed for example overnight (several hours). The substrate can be heated during drying e.g. up to 80° C. but it should not totally remove the organics.
In a preferred embodiment, no further thermal treatment (e.g. additional bake) is needed after performing the drying step. The absence of a further thermal treatment to remove the organic template is unusual and in contrast to current state of the art methods. In the preferred embodiments, it is recommended not to do a pre-UV thermal step such as an additional bake such that an optimal homogeneity is obtained and absence of cracks is seen.
Optionally but not preferred there can be an additional bake step before performing the UV treatment. Said bake step is used to remove part of organic material present in the silica-zeolite film. Said organic material is originating from the template and/or solvent used in the starting solution. Special care needs to be taken that there is still a residual amount of organic template available in the silica-zeolite film to obtain organic functionalization during subsequent UV treatment.
The UV treatment is preferably performed at wavelengths smaller than 300 nm. Applying said wavelengths can break the O—H bonds. Additionally the substrate comprising the silica-zeolite film is heated during the UV treatment to improve the UV treatment. The removal of silanol groups makes it possible to create new Si—O—Si cross-linking bridges. Also, upon UV exposure part of the C present in the organic component of the template is kept and found back in the form of Si—CH 3 and/or Si—O—CH 3 functional groups (referred to as organic functionalization), said —CH 3 and/or —O—CH 3 groups known to be effective hydrophobic groups. Solvents (if still presents) used could contribute to the organic functionalization but less likely, due to their high volatility.
During organic functionalization, Si—OH bonds are drastically decreased and new bonds appear, including Si—CH 3 and/or Si—O—CH 3 . An advantage of creating Si—CH 3 and/or Si—O—CH 3 bonds in the films is the fact that the density of the films is still low.
The UV treatment of pure-silica-zeolite films, with sufficient amount of organic template, will result in a significant improvement of hydrophobicity due to the removal of hydroxyl groups and the organic functionalization.
The removal of hydroxyl groups by means of silica condensation to form hydrophobic siloxane Si—O—Si bond will avoid moisture adsorption but has the tendency to increase the density of a pure-silica-zeolite film.
Said Si—O—Si bonds create new cross-linking bridges in the silica-zeolite film, leading towards higher mechanical strength. The decrease of the large Si—O—Si bonds lead towards improved mechanical properties.
To keep the density of the material low, it is preferred to have also significant degree of organic functionalization (meaning incorporation of “CH 3 ” groups). The density of a material, more specifically of a zeolites type material, is influenced by formation of firstly Si—O—Si bonds by silanol condensation which increases the density due to the (increased level) cross-linking. Secondly, by the formation of Si—CH 3 or Si—O—CH 3 , this also increases the density as more atoms fill the pores. In the UV treatment of the preferred embodiments, all the above mentioned effects end up in an increase of density.
During organic functionalization, Si—OH bonds are transformed into Si—CH 3 and/or Si—O—CH 3 bonds.
The introduction of new cross-linking bridges during UV treatment is mainly taking place in the amorphous part of the films because the amorphous part has significant higher concentration of silanol groups. Said Si—O—Si bonds create new cross-linking bridges in the pure-silica-zeolite film, leading towards higher mechanical strength.
Improvement in hydrophobicity can be investigated by means of ellipsometric porosimetry measurements (also referred to as ellipsometric measurements) as described in EP1722213 by Baklanov et al. Alternatively contact angle measurements with H 2 O can be performed. For a reference material (having complete wetting with water) the contact angle is typically ˜5 degrees. After UV treatment of the silica-zeolite film contact angle values of 100 degrees and higher can be obtained (typically 120 deg).
The removal of chemically bonded silanols can also be investigated by FTIR showing that after UV treatment a silica-zeolite film has a large reduction of trapped physisorbed moisture.
The organic functionalization and consequent hydrophobization can be further increased by adding more organic molecules to the zeolite film before UV light and temperature exposure to promote higher organic functionalization, for example methyltrimethoxysilane.
The silica-zeolite films after UV treatment of the preferred embodiments can be used as low-k dielectric material (i.e. material having a dielectric constant lower than the dielectric constant of SiO 2 ) in between (metallic) interconnect structures in a semiconductor device.
EXAMPLES
Example 1
Depositing a Silica-Zeolite Film
Zeolite films can be deposited in several ways: in-situ crystallization, spin-on of a zeolite particle suspension, dip-coating of a zeolite particle suspension, etc.
As described in this example and used as sample in further examples, spin coating can be used as deposition method and is performed as described below.
For the examples, spin-on pure-silica-zeolite MFI films are following the recipe proposed by Yan et al. (U.S. Pat. No. 6,630,696).
In that recipe, a clear solution is obtained with a molar composition of 1 Tetrapropyl-ammoniumhydroxide (TPAOH)/2.8 SiO 2 /22.4 Ethanol/40 H 2 O. This clear solution is aged under stirring at ambient temperature and then heated up to 80° C. during 3-5 days capped in a plastic vessel. Then, the nanoparticle suspension obtained is centrifuged at 5000 rpm for 20 minutes to remove big particles. The suspension is spun on Si wafers (substrates) at 3300 rpm during 20-30 seconds. The film obtained can be dried at 80° C. overnight.
Example 2
UV Treatment of a Zeolite Film
For the examples, a single wafer UV exposure system (RapidCure™ from Axcelis) tool was used. Exposure with a microwave-driven electrodeless bulb emitting UV light with a broadband spectrum was used. Inert gas ambient and ambient pressure was used. The wafer (substrate) with the pure-silica-zeolite film on top of it sits on a thermo chuck at temperature of 425° C. The exposure time is 5 minutes and the spectrum of the UV emission is lower than 300 nm.
Example 3
Yield Measurements (Crystallinity)
The synthesized silica-zeolite film had around 30% of zeolite nanocrystals (yield). The yield of said silica-zeolite film after deposition is the percentage of silica belonging to zeolite nanocrystals in the order of 50-70 nm. Thus, the final films in the example have around 30% of silica nanocrystals and the rest is amorphous silica. This amorphous phase contains zeolite seeds responsible of the creation of the silica nanocrystals, possibly nanoslabs and/or nanotablets as proposed by Kirschhock and co-authors.
Example 4
Porosity Measurements
Zeolite films of the example without UV treatment have an open porosity of 37.6%, measured by Ellipsoporosimetry with toluene.
In the case of UV treated the porosity is decreased to 27.9% because the film becomes denser.
Moreover there is an increase of refractive index in agreement with the densification of the film.
Clearly, the structure of the pure-silica-zeolite film is more cross-linked.
FIG. 3 illustrates the porosity of the pure-silica-zeolite film exposed to UV from Ellipsometric measurements performed with toluene.
Example 5
Contact Angle Measurements
The silica-zeolite film after UV-cure treatment according to a preferred embodiment (having a thermal activation during UV exposure) was evaluated for hydrophobicity by performing contact angle measurement.
For a given droplet on a substrate the contact angle is a measurement of the angle formed between the substrate and the line tangent to the droplet radius from the point of contact with the substrate.
The contact angle is related to the surface tension by the Young's equation through which the behavior of specific liquid-solid interactions can be calculated. A contact angle of zero results in complete wetting of the substrate, while an angle between 0 and 90 results in spreading of the drop (due to molecular attraction). Angles greater than 90 indicate that the liquid tends to bead or shrink away from the substrate, in case water is the liquid, the substrate can be interpreted as a hydrophobic substrate.
Contact angle measurements were done with water and a contact angle value of 118 (error is +−5) degrees was calculated fitting the curve to a Young-Laplace equation.
Example 6
Reduction of Cracks
Zeolite films containing an amorphous part suffer shrinkage during the removal of the template by thermal treatment. This shrinkage is mainly related to the amorphous part among nanocrystals.
In the case of higher yields (high ratio of zeolite nanocrystals), this shrinkage leads to the formation of cracks in the films (as shown in FIG. 5A ), probably due to the collapsing of pores.
When zeolite films are used as insulator in chips, these cracks will lead to the failure of chips because these cracks will create defects on the Cu barrier permitting the Cu diffusion.
This is solved using the UV treatment of the preferred embodiments because although the shrinkage is practically the same, the better cross-linking of the zeolite film avoids the formation of cracks. The silica-zeolite film after UV treatment is shown in FIG. 5B and shows almost no cracks.
All references cited herein are incorporated herein by reference in their entirety. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.
The term “comprising” as used herein is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.
All numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances 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 present invention. 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 be construed in light of the number of significant digits and ordinary rounding approaches.
The above description discloses several methods and materials of the present invention. This invention is susceptible to modifications in the methods and materials, as well as alterations in the fabrication methods and equipment. Such modifications will become apparent to those skilled in the art from a consideration of this disclosure or practice of the invention disclosed herein. Consequently, it is not intended that this invention be limited to the specific embodiments disclosed herein, but that it cover all modifications and alternatives coming within the true scope and spirit of the invention as embodied in the attached claims. | A method is provided for making pure-silica-zeolite films useful as low-k material, specifically, more hydrophobic, homogeneous and with absence of cracks. The method utilizes a UV cure; preferably the UV cure is performed at temperatures at higher than the deposition temperature. The UV-assisted cure removes the organic template promoting organic functionalization and silanol condensation, making the silica-zeolite films more hydrophobic. Moreover, the zeolite material is also mechanically stronger and crack-free. The method can be used to prepare pure-silica-zeolite films more suitable as low-k materials in semiconductor processing. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to electronic ignition systems for internal combustion engines, and particularly to a device for the automatic variation of the spark advance in such an electronic ignition-system.
A number of different arrangements for varying the spark advance in electronic ignition systems for internal combustion engines are already known; this invention relates particularly to electronic systems for the automatic variation of the spark advance, which systems generally comprise an ignition spark discharge control circuit, and a circuit for varying the instant of discharge, which circuit is controlled by reference means located on a rotating element, generally the flywheel of the internal combustion engine.
Such reference means usually comprise a series of notches and corresponding teeth, of ferromagnetic material, spaced around the circumference of the flywheel or other rotating element in such a manner as to provide a detectable varying magnetic flux as the element rotates; a system for detecting the variation of the flux comprising, for example, one or more electromagnetic pick-ups, which cooperates with the ferromagnetic reference means on the rotating element so as to detect the speed of rotation and phase of the rotating element, and finally, electronic circuits responsive to the output signal from the pick-up for controlling the discharge of the ignition spark, operating to increase the spark advance as the speed of the engine increases.
Known ignition timing control systems are generally constructed in such a manner as to provide the spark at a minimum angular advance setting, in relation to the point of maximum compression of the charge in the cylinder, corresponding to a selected minimum speed of the engine, and the ignition advance increases linearly with the speed of the engine to reach a constant fixed value when the engine reaches a predetermined maximum speed.
The form of the ignition advance curve achieved by such known devices, however, only approximates to the actual curve required for the optimum functioning of the engine, which curve is usually of more complex form, and is different for different types of engine.
In order to approximate more closely the curves required in practice for certain types of engines, it is possible to use circuits which produce curves in which the part which varies linearly with the speed of the engine, is substituted by two straight lines of differing slope.
OBJECT OF THE INVENTION
The object of the present invention is to produce a device for controlling the ignition timing of an internal combustion engine, which is particularly simple, efficient and of low cost, but at the same time permits the production of a variable ignition advance having a curve including two straight lines for more closely approximating the required complex curve.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a device for the automatic variation of the ignition spark advance angle in an electronic ignition system for an internal combustion engine, of the type comprising an ignition spark discharge control circuit, and a device for varying the instant of discharge of the ignition spark, wherein said device comprises: reference means located on a rotating member of the engine which turns with the crankshaft, said reference means comprising: at least one protuberance phase displaced in advance of a position on said rotating member representing the top dead centre position of said crankshaft of said engine by an angle θm equal to the maximum spark advance angle required, said protuberance defining a reference position of said crankshaft, and a series of teeth on said rotating member, first pick-up means sensitive to the passage therepast of said teeth on said rotating member and responsive thereto to produce a train of pulses representing the speed of rotation of said rotating member; first counting means for counting said train of pulses from said first pick-up means during each ignition timing cycle of said engine, second pick-up means responsive to the passage therepast of said at least one protuberance to produce a pulse indicating said reference position of said crankshaft, means responsive to the output of said first counting means operating to initiate the ignition spark when said first counting means reach a predetermined count, first logic gating means connected to the output of said first pick-up means, the output from said first logic gating means being connected to the input of said first counting means, said first logic gating means selectively permitting the passage of pulses fed thereto to said first counting means, second counting means for counting the pulses produced by said first pick-up means from the moment when said protuberance passes said second pick-up means indicating that said crankshaft of said engine is at said reference position, timing circuit means operating to produce a timing signal output a predetermined time T after an input signal has been fed thereto, switching circuit means having a control input connected to the output from said second counting means, the output from said switching circuit means being connected to the input of said timing circuit, the output of said timing circuit being connected to a second input of said first logic gating means, frequency doubling means connected between said first logic gating means and said first counting means, said frequency doubling means operating to double the frequency of the pulses produced by said first pick-up means in the time interval between the instant when said crankshaft is in said reference position and the instant of discharge of the ignition spark, and if the speed of the engine is lower than a predetermined threshold n 1 , also during said timing interval T or part thereof.
Further characteristics and advantages of the invention will become apparent from a consideration of the following description, provided by way of example only, with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating one embodiment of the invention;
FIG. 2 is a diagram of a detail of FIG. 1;
FIGS. 3 and 4 are diagrams illustrating the variation of the ignition advance angle θ in dependence on the number of revolutions per minute n of the engine of two different embodiments, and
FIGS. 5 to 13 represent wave forms of the signals formed at various points of the circuits of the embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIGS. 1 and 2 there is shown a rotating element 2 of an internal combustion engine which is not shown in detail. The rotating element may be, for example, a flywheel on whose periphery is located a ring gear 3, only a part of which is shown in the drawings, and which may be the usual starting ring gear to be found on the flywheels of most internal combustion engines of motor vehicles.
On the face of the flywheel 2 is a protuberance 4 which is displaced by an angle θ m in advance (with respect to the direction of rotation of the flywheel) of a reference mark 6 which indicates, with reference to another mark on the crankcase (not shown) when the flywheel is in the position corresponding to top dead centre of the crankshaft.
The angle θ m corresponds to the maximum ignition advance angle it is wished to achieve. Facing the rim of the flywheel 2 there is situated an electromagnetic pick-up 1 which produces electric pulses as the teeth move past, the pulse rate thus representing the speed of the engine. The electric pulses are passed to a squarer 8 connected to a first input 10 of a NAND gate 12 the output from which is fed to a differentiator 14 connected to a first input 16 of a NAND gate 18, the output from which is fed to a first input 20 of a main counter 22.
A further sensor 24 is positioned opposite the face of the flywheel 2 at a radial position corresponding to that of the aforementioned protuberance 4; the further sensor 24 produces one electrical pulse each time the protuberance 4 passes close to it.
The output signal from the further sensor 24 is fed to a pulse shaper 25 the output from which is connected to the reset input 27 of a counter 28, shown in FIG. 1 as a 3 bit counter and therefore with 3 outputs, the main input 29 of which is connected to the output of the squarer 8; the output of the pulse shaper 25 is also fed to the set input 30 of a bistable circuit 31.
Two of the outputs, indicated 32 and 34, of the counter 28 are fed to two inputs of a NAND gate 35 the output from which is taken to reset input 36 of the bistable circuit 31.
The third output, 37, of the counter 28 is fed to a first input of a NAND gate 38 the second input of which is always maintained at a positive value; the output of the NAND gate 38 is connected to a first input of a NAND gate 39 the second input of which is connected to a switch 40 which is selectively connectable through a resistance 41 to a voltage source, or to earth; the output of the gate 39 is fed to a third input of the NAND gate 35.
The three gates 35, 38 and 39 act as a coincidence circuit acting to input signals from the counter 28 to the bistable 31 only when they have predetermined logic levels which will be described in greater detail below.
The output of the bistable 31 is fed to the input of a monostable multivibrator 42 and also to the input of an inverter 43, the input of a differentiating circuit 44 and the first input 45 of a NAND gate 46.
The second input 48 of the NAND gate 12 is fed from the output of a NAND gate 49 having two inputs one of which, 50, is fed from the output of the monostable 42 and the other of which, 51, is fed with the output of the inverter 43. The gate 12 has three inputs the third, 52, of which is connected to the output of a NAND gate 54 and to the input of an inverter 56 connected to a second input 58 of the NAND gate 46.
The output of the NAND gate 46 is fed to a first input 59 of a monostable circuit 60 the second input 62 of which is fed from the output of the differentiating circuit 44. The output of the NAND gate 12 is also fed to a first input 63 of a NAND gate 64 the second input 65 of which is fed by the output of a NAND gate 66. The NAND gate 66 has two inputs 69b and 69a which are connected respectively to the output of the inverter 43 and to the output 67 of the main counter 22. The output of the gate 64 feeds a differentiating circuit 68 connected to a second input 70 of the NAND gate 18.
The output of the inverter 43 is also fed to a differentiating circuit 71 the output from which is fed to the reset input 72 of the main counter 22.
The main counter 22 which is also shown as a 3 bit counter, has three outputs 67, 74, 76 connected to three inputs of a NAND gate 54.
FIG. 3 illustrates the relation between the speed of the engine (expressed as number of revolutions per minute n) and the ignition spark advance angle achieved by the control device of the invention. In this diagram there is a first straight line section a followed by a second straight line section b having a slope half that of the section a, and finally a substantially horizontal section representing an unchanging spark advance angle when the engine is turning at a speed higher than a predetermined value n 2 , the maximum spark advance angle then having the constant value θ m.
The operation of the device will now be described with particular reference to FIGS. 5 to 13 and considering a a cycle between two successive passages of the protuberance 4 past the detector 24, assuming that the switch 40 is connected to earth.
FIGS. 5, 6, 7 and 8 represent, as a function of time t, the state V of the signals, respectively at the output of the pick-up 24, at the output of the bistable circuit 31, at the output of the monostable 42 and finally at the input 48 of the gate 12. FIGS. 9 to 13 represent, as a function of the time t, the state V of the signals at other characteristic points of the circuit as will be described below.
The pulses from the first sensor 1, produced by the passage of the teeth 3 of the flywheel 2 moving past this sensor are fed into the pulse shaper 8 and from there to the clock input 29 of the counter 28.
The pulse due to the passage of the protuberance 4 past the second sensor 24 is produced at an instant t o when the engine crankshaft is at an angle with respect to its top dead centre position corresponding to the maximum spark advance angle θ m, and goes to the counter 28 setting it to zero cancelling the count accumulated in the preceding cycle and enabling it to count from zero for the new cycle; the same signal goes to the bistable 31 setting it, that is taking its output to the logic level 1.
The counter 28 is arranged so that, at a time t 2 , when it has counted a number of teeth corresponding to the maximum spark advance angle θ m (which means that at least one piston of the engine has reached the top dead centre position) the three outputs of the counter 28 are at logic level 1 so that, if the switch 40 is connected to earth, the outputs of the gates 38 and 39 of the coincidence circuit are at logic level 0 and 1 respectively and thus the three inputs of the NAND gate 35 are at logic level 1 so its output is therefore at logic level 0. The reset input 36 of the bistable 31 is fed with the output of the NAND gate 35 and its output thus changes to logic level 0.
The switching of the bistable 31 occurs therefore at the instant when the crankshaft passes through the top dead centre position. In the meantime the ignition circuits of that part of the device situated downstream from this point cause, at the time t 1 , as will be seen from the description below, the production of a spark with an advance angle as established by the device itself in the preceding cycle.
The trailing edge of the output signal from the bistable 31 switches the monostable 42 at the time t 2 ; the latter remains switched for a predetermined time T. The same signal from the bistable 31 is fed to the input of the inverter 43.
The monostable 42 has an output which is normally at logic level 1 and which is taken to level 0 when it is switched by the signal from the bistable 31 at the dead centre position of the crankshaft. The output signal from the monostable 42, together with the output signal from the bistable 31, inverted by the inverter 43, is fed to the inputs of the NAND gate 49 the output from which thus serves to permit or prevent the passage of pulses originating from the sensor 1 through the gate 12.
The output from the NAND gate 49 effectively controls the NAND gate 12 because, when pulses from the sensor 1 are present at the input 10 of the gate 12, since, as will be seen later, the input 50 of the gate 49 is kept at logic level 1 from one instant t 3 when the crankshaft passes through the top dead centre position until the instant t 2 ' of the following ignition cycle, the said pulses can pass through the gate 12 during the time interval T during which the monostable is switched, and during the time interval between the instant t o ' and the following switch instant t 1 ', shown hatched in FIG. 8.
During these time intervals the pulses which pass through the gate 12, represented in FIG. 9, are differentiated at their trailing or negative-going edges by the differentiating circuit 14 so that the pulses at the input 16 of the gate 18 are in the form as shown in FIG. 10.
During the time interval t O- t 1 , that is between the instant when the crankshaft passes through the maximum spark advance angle and the instant when the ignition spark is produced, the frequency of the pulses arriving at the input 20 of the main counter 22 is twice that of the pulses from the sensor 1. In fact during this interval the input 65 of the gate 64 is at logic level 1, therefore the pulses arriving at the input 63 of this gate pass, inverted, through it and the differentiating circuit 68 differentiates them in response to their negative-going or trailing edge. Consequently the output of the gate 18 is two series of pulses fed to the gate 18 from the two differentiators 14 and 58.
FIGS. 11 and 12 represent respectively the pulses at the output of the gate 64 and those at the output of the differentiating circuit 68, whilst FIG. 13 represents the pulses at the output of the gate 18.
During the switching interval T of the monostable 42 the number of pulses fed to the counter 22 is controlled by the speed of the engine. At the start of the switching interval of the monostable, the signal in the output line 67 of the counter is at logic level 0 and therefore the inputs 69a and 69b of the NAND gate 66 are respectively at logic level 0 and logic level 1, so that the output of this gate is at logic level 1. Pulses at the input 63 of the gate 64 are thus passed thereby as previously described and the counter 22 is fed with pulses at double the frequency of the sensor 1. When the counter has counted a number of pulses such that its output line 67 (and therefore the input 69a of the gate 66) switches to logic level 1, then since the two inputs of the gate 66, are not at level 1, the output of the gate 66 switches to logic level 0 and the passage of pulses through the differentiating circuit 68 is blocked so that the counter 22 is fed only with the train of pulses from the differentiator 14.
During the subsequent interval t o ' - t 1 ' the counter 22 completes the count up to a predetermined number at which all its outputs are at logic level 1, and when this occurs, at the instant t 1 ', it controls the ignition spark discharge in a manner which will be described below.
The output on line 67 of the counter 22 can only reach the logic level 1 during the time period T if the number of revolutions of the engine is above a certain value nl, whereas for speeds lower than this value the logic level 1 on the line 67 is never reached during the time interval T. In the first case the device controls a variation of the spark advance in accordance with part b of the line shown in FIGS. 3 and 4, and in the second case to a variation according to part a of the line shown in these Figures.
The control of the ignition spark discharge to occur at the time t 1 ', that is on completion of the total count by the counter 22 when the inputs of the gate 54 are all at logic level 1, takes place as follows: when the inputs to the gate 54 are all at logic level 1 the output of this gate is a signal at logic level 0 which is fed both to the input 52 of the gate 12 and to the inverter 56. The gate 12 then blocks the passage of pulses from the sensor 1.
At the input 45 of the gate 46 there is already present a signal at logic level 1 so that when the input 58 of the gate is switched by the inverter 56 to the logic level 1, the gate 46 causes the switching of the spark discharge monostable 60. The signal at the output of this monostable circuit acts on the ignition control elements (not shown in the drawings) for example on a power transistor, which controls the discharge of the ignition coil. The monostable 60 has a switching time equal to the desired duration of the ignition spark.
By connecting the switch 40 directly to earth the output of the gate 39 always remains at logic level 1 and consequently the gate 35 produces the coincidence signal at a lower count at the output of the counter 28 than it would with the switch connected to the resistor 41, in which case the output of the gate 39 could commute between levels 1 and 0 depending on the logic level of the output 37 of the counter 28 since the input to the gate 39 via the switch 40 is effectively held at logic level 1.
In this manner a fictitious top dead centre position is created in advance by a predetermined angle with respect to the position of the real top dead centre. This ensures that the ignition spark advance angle is maintained at a certain minimum value when the engine is turning at low speed, as shown in FIG. 4, rather than falling to a zero advance angle as would be the case with the switch 40 held in the position shown in FIG. 1, as illustrated in FIG. 3. | A device for automatically varying the ignition spark advance angle in an electronically controlled ignition system for an internal combustion engine, in which there is a first sensor for producing a train of pulses the pulse repetition frequency of which represents the engine speed and a second sensor for producing a single pulse once each revolution of the engine when the crankshaft is at the top dead center position. A pulse counter counts the pulses from the first sensor and acts to discharge the ignition spark when it reaches a predetermined count: this counter is reset to zero each cycle by the pulse from the second sensor, there is also a timing device which sets a predetermined time interval in advance of the top dead center position and means for doubling the frequency of the pulses counted by the said counter for varying the rate at which the spark advance angle varies with change in speed of the engine, depending on whether the engine speed is above or below a threshold speed determined by the timing interval of the said timing circuit. | 8 |
BACKGROUND
1. Technical Field
Embodiments of the present disclosure relate generally to switch testing, and more particularly, to a system and method for testing a peripheral component interconnect express (PCI-E) switch of a computing device.
2. Description of Related Art
PCI-E switches are used in computing devices, and the operating ability of the PCI-E switches must be tested. Usually, a PCI-E switch is tested using a circuit tester (ICT) or a flying probe. Because the ICT and the flying probe test are both open circuit tests, it is difficult and inconvenient to test the data transmission function of the PCI-E switch, so what is needed is a test method that overcomes the limitations described.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of one embodiment of a computing device including a test system for testing a PCI-E switch.
FIG. 2 is a block diagram of one embodiment of the functional modules of the test system included in the computing device of FIG. 1 .
FIG. 3 is a flowchart of one embodiment of a method for testing a PCI-E switch using the test system of FIG. 1 .
DETAILED DESCRIPTION
The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
FIG. 1 is a block diagram of one embodiment of a computing device 1 including a test system 100 . In the embodiment, the computing device 1 further includes a storage system 10 , a first motherboard 11 , at least one processor 12 and a monitor 13 . The first motherboard 11 includes a first PCI-E switch 110 that electronically connects to a second PCI-E switch 20 to be tested on a second motherboard 2 . The test system 100 can test the data transmission function of the second PCI-E switch 20 . The monitor 13 displays a test result of the second PCI-E switch 20 . In one embodiment, the computing device 1 may be a desktop computer, a notebook computer, a server, a workstation or other. It should be apparent that FIG. 1 is just one example of the computing device 1 that can be included with more or fewer components than shown in other embodiments, or a different configuration of the various components.
The storage system 10 stores one or more programs, such as an operating system, and other applications of the computing device 1 . In one embodiment, the storage system 10 may be random access memory (RAM) for temporary storage of information, and/or a read only memory (ROM) for permanent storage of information. In other embodiments, the storage system 10 may also be an external storage device, such as a hard disk, a storage card, or a data storage medium. The at least one processor 12 executes computerized operations of the computing device 1 and other applications, to provide functions of the computing device 1 .
FIG. 2 is a block diagram of one embodiment of the functional modules of the test system 100 included in the computing device 1 of FIG. 1 . The test system 100 may include a plurality of functional modules each comprising one or more programs or independent code and which can be accessed and executed by the at least one processor 12 . In one embodiment, the test system 10 includes a creation module 101 , a sending module 102 , a receiving module 103 , a comparison module 104 , and a display module 105 . In general, the word “module”, as used herein, refers to logic embodied in hardware or firmware, or to a collection of software instructions, written in a programming language, such as, Java, C, or assembly. One or more software instructions in the modules may be embedded in firmware, such as EPROM. The modules described herein may be implemented as either software and/or hardware modules and may be stored in any type of non-transitory computer-readable medium or other storage device. Some non-limiting examples of non-transitory computer-readable media include CDs, DVDs, BLU-RAY, flash memory, and hard disk drives.
Prior to testing, the second PCI-E switch 20 should be put into a loopback mode, which in this embodiment may be defined as a mode for the exchange of data between the first PCI-E switch 110 and the second PCI-E switch 20 . In the loopback mode, the second PCI-E switch 20 returns the data packets to the first PCI-E switch 110 when the second PCI-E switch 20 receives data packets from the first PCI-E switch 110 . Putting the second PCI-E switch 20 into the loopback mode can be done writing a loopback instruction to a register of the second PCI-E switch 20 .
The creation module 101 is operable to create a first data packet using a plurality of formatted data. The first data packet consists of the formatted data that can be transmitted between the first PCI-E switch 110 and the second PCI-E switch 20 .
The sending module 102 is operable to send the first data packet from the first PCI-E switch 110 to the second PCI-E switch 20 . After the second PCI-E switch 20 receives the first data packet, the second PCI-E switch 20 generates a second data packet based on the first data packet, and sends back the second data packet to the first PCI-E switch 110 .
The receiving module 103 is operable to receive the second data packet sent back by the second PCI-E switch 20 .
The comparison module 104 is operable to compare the first data packet with the second data packet to generate a test result of the second PCI-E switch 20 .
The display module 105 is operable to display the test result of the second PCI-E switch 20 on the monitor 13 . If the first data packet is identical to the second data packet, the display module 105 activates the monitor 13 to display information indicating that the second PCI-E switch 20 works normally. If the first data packet is not identical to the second data packet, the display module 105 activates the monitor 13 to display an error code indicating that the second PCI-E switch 20 does not work normally.
FIG. 3 is a flowchart of one embodiment of a method for testing a PCI-E switch using the test system 100 of FIG. 1 . Depending on the embodiment, additional blocks may be added, others removed, and the ordering of the blocks may be changed.
In the embodiment, the second PCI-E switch 20 of the second motherboard 2 is to be tested, and is electronically connected to the first PCI-E switch 110 of the first motherboard 11 . Before testing, the second PCI-E switch 20 is put into the loopback mode, and as described above, the loopback mode is defined as a mode for the exchange of data between the first PCI-E switch 110 and the second PCI-E switch 20 .
In block S 100 , the creation module 101 creates a first data packet (which can be exchanged between the first PCI-E switch 110 and the second PCI-E switch 20 ) using a plurality of formatted data.
In block S 102 , the sending module 102 sends the first data packet from the first PCI-E switch 110 to the second PCI-E switch 20 . After the second PCI-E switch 20 receives the first data packet, the second PCI-E switch 20 generates a second data packet based on the first data packet, and sends back the second data packet to the first PCI-E switch 110 .
In block S 104 , the receiving module 103 receives the second data packet sent back by the second PCI-E switch 20 .
In block S 106 , the comparison module 104 compares the first data packet with the second data packet. If the first data packet is not identical to the second data packet, block S 108 is implemented. If the first data packet is identical to the second data packet, block S 110 is implemented.
In block S 108 , the display module 105 activates the monitor 13 to display an error code indicating that the second PCI-E switch 20 does not work normally. In block S 110 , the display module 105 activates the monitor 13 to display information indicating that the second PCI-E switch 20 works normally.
Although certain embodiments of the present disclosure have been specifically described, the present disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the present disclosure without departing from the scope and spirit of the present disclosure. | A method tests peripheral component interconnect express (PCI-E) switches. A second PCI-E switch to be tested electronically connects to a first PCI-E switch of a computing device. A first data packet is created by the computing device and sent from the first PCI-E switch to the second PCI-E switch. A second data packet sent back by the second PCI-E switch is received by the computing device. The second PCI-E switch works normally if the first data packet is identical to the second data packet. The second PCI-E switch does not work normally if the first data packet is not identical to the second data packet. | 6 |
BACKGROUND OF THE INVENTION
This invention relates to an image forming apparatus and method applied to an electronic copying machine, and more specifically to an image forming apparatus which comprises a photosensitive body holding an electric charge, charging means for applying an electric charge to the photosensitive body, exposure means for optically scanning an image of an original and exposing the photosensitive body charged by the charging means, thereby forming an electric charge pattern in response to the original image, and developing means for developing the electric charge pattern formed on the photosensitive body by exposure techniques.
In general, electronic copying machines copy an image of the original onto a paper sheet directly or in an enlarged or reduced scale. An electronic copying machine of this type is known which is adapted for copying (at a reduced or enlarged scale) an original placed on the document table, with the size and number of copies determined by indicators disposed on the reverse side of the document table. If the copying range is indicated, it is possible to prevent a possible setting error in the copying size.
However, this type of machine is very expensive, because the indicators are driven by dedicated motors.
SUMMARY OF THE INVENTION
It is accordingly an object of this invention to provide an image forming apparatus which can provide an inexpensive display means without increasing the number of component parts required.
According to the present invention, method and apparatus are provided for displaying an image-reproducible range of an original sheet in accordance with a selected magnification/reduction factor. The display device includes two indicators positioned adjacent the original document table and movable with respect to each other to indicate a first magnification/reduction dimension on the document table. An optical scanning device includes an indicator which moves relative to the original document table to indicate the second dimension of the magnification/reduction range. Preferably, an interlocking device drives the display device with the movement of the optical scanning device. Control circuitry preferably drives the interlocking device in accordance with the selected magnification/reduction factor and the size of the sheet upon which the magnification/reduction image is to be made. The invention also provides a method for moving the indicators and the carriage in order to visually depict the image-reproducible range.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are a schematic perspective view and a side sectional view, respectively, showing the construction of the image forming apparatus;
FIG. 3 is a plan view of a control panel;
FIG. 4 is a perspective view showing an arrangement of drive sections;
FIG. 5 is a perspective view schematically showing a drive mechanism for an optical system;
FIG. 6 is a block diagram showing a general control circuit;
FIG. 7 is a perspective view showing only the major part of the image forming apparatus which permits indicators to be moved relative to each other in interlocking movement with the first carriage movement to set an image-reproducible range;
FIG. 8 is a side view showing the holding means of the apparatus with a portion of FIG. 7 removed;
FIG. 9 is a flow chart for explaining the processor functions for displaying an image-reproducible range;
FIG. 10 is a plan view for explaining the operation of FIGS. 7 and 8; and
FIG. 11 is a perspective view showing only the major part of another image forming apparatus which permits indicators to be moved relative to each other in interlocking movement with the first carriage to set an image-reproducible range.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
One embodiment of this invention will now be described in detail with reference to the accompanying drawings.
FIGS. 1 and 2 schematically show a copying machine as an image forming apparatus according to an exemplary embodiment of this invention. In FIGS. 1 and 2, numeral 1 designates a housing of the copying machine. An original table 2 (transparent glass) for carrying an original is fixed on the top of housing 1 (original cover is not shown). The original document set on original table 2 is scanned for image exposure by optical system 3 including exposure lamp 4 and mirrors 5, 6 and 7 which reciprocate in the direction indicated by arrow `a` along the under surface of the original table 2. In this case, mirrors 6 and 7 move at a speed half that of mirror 5 so as to maintain a fixed optical path length.
Exposure lamp 4 illuminates the original document. A light beam reflected from the original is scanned by optical system 3, is further reflected by mirrors 5, 6 and 7, transmitted through lens block 8 for magnification or reduction, and then reflected by mirror 9 to be projected on photosensitive drum 10. Thus, an image of the original is formed on the surface of photosensitive drum 10.
Photosensitive drum 10 rotates in the direction indicated by arrow `c` so that its surface is completely precharged by main charger 11. The image of the original is projected on the charged surface of photosensitive drum 10 by split exposure, forming an electrostatic latent image on the surface. The electrostatic latent image is developed into a visible image (toner image) by developing unit 12 using toner. Paper sheets (image record media) `P` are delivered one by one from upper paper cassette 13 or lower paper cassette 14 by paper-supply roller 15 or 16, and guided along paper guide path 17 or 18 to aligning roller pair 19. Then, each paper sheet `P` is delivered to the transfer region by aligning roller pair 19, timed to the formation of the visible image.
Paper cassettes 13 and 14 are removably attached to the lower right end portion of housing 1, and can be alternated by selective operation on the control panel which will be described in detail later. Paper cassettes 13 and 14 are provided with cassette size detecting switches 60 1 and 60 2 which detect the selected cassette size. Detecting switches 60 1 and 60 2 are each formed by microswitches which are turned on or off in response to insertion of cassettes of different sizes.
Paper sheet `P` delivered to the transfer region comes into close contact with the surface of photosensitive drum 10, in the space between transfer charger 20 and drum 10. As a result, the toner image on photosensitive drum 10 is transferred to paper sheet `P` by charger 20. After the transfer, paper sheet `P` is separated from the photosensitive drum 10 by separation charger 21 and transported by conveyor belt 22. Thus, paper sheet `P` is delivered to fixing roller pair 23 which is arranged at the terminal end portion of conveyor belt 22. As paper sheet `P` passes through fixing roller pair 23, the transferred image is fixed on sheet `P`. After the fixation, paper sheet `P` is discharged into tray 25 outside housing 1 by exit roller pair 24.
After the transfer, photosensitive drum 10 is de-electrified by de-electrification charger 26, when the residual toner on the surface of drum 10 is removed by cleaner 27. Thereafter, a residual image on photosensitive drum 10 is erased by discharge lamp 28 to restore it to the initial state. In FIG. 2, numeral 29 designates a cooling fan for preventing the temperature inside housing 1 from rising.
FIG. 3 shows control panel 30 mounted on housing 1. Control panel 30 carries thereon: copy key 30 1 for starting the copying operation, ten-keys 30 2 for setting the number of copies to be made and the like, display section 30 3 for indicating the operating conditions of the individual parts or paper jamming, cassette selection keys 30 4 for alternatively selecting upper or lower paper cassette 13 or 14, and cassette display section 30 5 for indicating the selected cassette. Control panel 30 is further provided with ratio setting keys 30 6 for setting the enlargement or reduction ratios, zoom keys 30 7 for adjustably setting the enlargement or reduction ratio, display section 30 8 for displaying the set ratio, and density setting section 30 9 for setting the copy density.
FIG. 4 shows a specific arrangement of drive sources for individual drive sections of the copying machine constructed in this manner. The drive sources include the following motors. Numeral 31 designates the motor for the lens drive. Lens drive motor 31 serves to shift the position of lens block 8 for magnification or reduction. Numeral 32 designates the motor for mirror drive. Mirror drive motor 32 serves to change the distance (optical path length) between mirror 5 and mirrors 6 and 7 for magnification or reduction. Numeral 33 designates the motor for scanning. Scanning motor 33 serves to move exposure lamp 4 and mirrors 5, 6 and 7 for scanning the original. Numeral 34 designates the motor for the shutter drive. Shutter drive motor 34 serves to move the shutter (not shown) for adjusting the width of charging of photosensitive drum 10 by charger 11 at the time of magnification or reduction.
Numeral 35 designates the motor used for developing. Developing motor 35 serves to drive the developing roller and the like of developing unit 12. Numeral 36 designates the motor used to drive the drum. Drum drive motor 36 serves to drive photosensitive drum 10. Numeral 37 designates the motor for fixation. Fixing motor 37 serves to drive sheet conveyor belt 22, fixing roller pair 23, and exit roller pair 24. Numeral 38 designates the motor for paper supply. Paper supply motor 38 serves to drive paper supply rollers 15 and 16. Numeral 39 designates the motor for feeding sheets. Sheet feed motor 39 serves to drive aligning roller pair 19. Numeral 40 designates the motor for fan drive. Fan drive motor 40 serves to drive cooling fan 29.
FIG. 5 shows the drive mechanism for reciprocating optical system 3. Mirror 5 and exposure lamp 4 are supported by first carriage 41 1 , and mirrors 6 and 7 by second carriage 41 2 . Carriages 41 1 and 41 2 move in parallel in the direction indicated by arrow `a`, guided by guide rails 42 1 and 42 2 . Four-phase pulse motor 33 drives pulley 43. Endless belt 45 is stretched between pulley 43 and idle pulley 44, and one end of first carriage 41 1 supporting mirror 5 is the intermediate portion of belt 45.
On the other hand, two pulleys 47 are rotatably attached to guide portion 46 (for rail 42 2 ) of second carriage 41 2 supporting mirrors 6 and 7, spaced in the axial direction of rail 42 2 . Wire 48 is connected between two pulleys 47. One end of wire 48 is connected thereto by means of coil spring 50. One end of first carriage 41 1 is fixed to the intermediate portion of wire 48.
With this arrangement, when pulse motor 33 is driven, belt 45 turns around to move first carriage 41 1 . As first carriage 41 1 travels, second carriage 41 2 also travels. Since pulleys 47 serve as movable pulleys, second carriage 41 2 travels in the same direction as and at a half speed of first carriage 41 1 . The travelling direction of first and second carriages 41 1 and 41 2 is controlled by changing the rotating direction of pulse motor 33.
FIG. 6 shows a general control circuit of the electronic copying machine. This control circuit is mainly composed of main processor group 71 and first and second sub-processor groups 72 and 73. Main processor group 71 detects input data from control panel 30 and group of input devices 75 including various switches and sensors, such as cassette size detection switches 60 1 and 60 2 , and controls high voltage transformer 76 for driving the chargers, discharge lamp 28, blade solenoid 27a of cleaner 27, heater 23a of fixing roller pair 23, exposure lamp 4, and motors 31 to 40, thus accomplishing the copying operation.
Motors 35, 37 and 40 and toner-supply motor 77 for supplying the toner to developing unit 12 are connected through motor driver 78 to main processor group 71 to be controlled thereby. Motors 31 to 34 are connected through pulse motor driver 79 to first sub-processor group 72 to be controlled thereby. Motors 36, 38 and 39 are connected through pulse motor driver 80 to second sub-processor group 73 to be controlled thereby.
Further, exposure lamp 4 is controlled by main processor group 71 through lamp regulator 81, and heater 23a by main processor group 71 through heater control section 82. Main processor group 71 gives instructions for the start or stop of the individual motors to first and second sub-processor groups 72 and 73. First and second sub-processor groups 72 and 73 feed main processor group 71 with status signals indicative of the operation mode of the motors. Also, first sub-processor group 72 is supplied with positional information from position sensor 83 for detecting the respective initial positions of motors 31 to 34.
An output signal of position detector 106, as set out below, is supplied to the above-mentioned main processor group 71. Drive circuit 112 for driving holding means 107, as set out below, is operated by an output signal of main processor group 71.
Original table 2 carries thereon an indication of an image-reproducible range corresponding to the size of the designated paper sheets. If the sheet size designated by sheet selection keys 30 4 and the copy ratio specified by ratio setting keys 30 4 or 30 7 are (Px, Py) and K, respectively, the image-reproducible range (x, y) is given by
x=Px/K,
y=Py/K.
Out of the coordinates (x, y) designating any point within the image-reproducible range, as shown in FIG. 1, the x coordinate is indicated by indexes 51 and 52 arranged on the inside of original table 2, and the y coordinate by scale 53 provided on the top face portion of first carriage 41 1 .
FIG. 7 shows the details of indicators 51,52. Indicators 51, 52 are driven by wires 100 stretched between pulleys 101 and 102 through spring 103. Pulleys 104 and 105 are located intermediate between pulleys 101 and 102. Wire 100 is bent at right angles at the positions of pulleys 104 and 105 where it extends along the lateral and longitudinal directions of table 2. Indicators 51 and 52 are located one between pulleys 101 and 104 and one between pulleys 101 and 105. Position detector 106 is provided in the neighborhood of indicator 51 and comprised of, for example, a photocoupler and is adapted to detect indicator 51. An output signal of position detector 106 is supplied to main processor group 71.
Holding means 107 is provided between pulleys 102 and 104, 105 and serves as an interlocking means capable of selectively holding one of two parallel runs of wire 100. Holding means 107 comprises electromagnet 108, armature 109, pressure contact member 110 and spring 111 as shown in FIG. 8. Armature 109 is attracted by electromagnet 108 and pressure contact member 110 holds wire 100 with armature 109 attracted thereto. Pressure contact member 110 is made of a material of a high coefficient of friction, such as rubber, to permit wire 100 to be gripped or held in cooperation with armature 109. Spring 111 normally urges armature 109 away from electromagnet 108. Holding means 107 is attached to first carriage 41 1 . Holding means 107 is excited through drive circuit 112 operated by an output signal of main processor group 71.
The operation of main processor group 71 for image-reproducible range display will now be explained below with reference to the flow chart of FIG. 9. Suppose that indicators 51, 52 and scale 53 of first carriage 41 1 are located in position (X 1 , Y 1 ) as shown in FIG. 10. In this state, when ratio setting key 30 6 and zoom key 30 7 on control panel 30 are operated, drive circuit 112 is operated to permit electromagnet 108 on holding means 107 to be excited (Step 1). By so doing, wire 100 is sandwiched in proper place between armature 109 and pressure contact member 110. In this state, pulse motor 33 is driven so as to cause first carriage 41 1 to be moved away from indicators 51, 52 (Step 2). When this is done, wire 100 is operated in cooperation with first carriage 41 1 to permit indicators 51, 52 to be moved away from each other. Pulse motor 33 is driven until indicator 51 is detected by position detector 106 after it has been moved by distance l 1 (Step 3). When pulse motor 33 is stopped, pulse motor 33 and thus first carriage 41 1 are stopped (Step 4). Then, pulse motor 33 is driven so that first carriage 41 1 is moved toward indicators 51, 52 (Step 5). Pulse motor 33 is driven until indicators 51 and 52 are moved distance l 2 relative to each other so as to obtain distance X 2 therebetween corresponding to a set ratio (Step 6). With the indicators so moved by distance l 2 , pulse motor 33 and then first carriage 41 1 are stopped (Step 7). In this state, electromagnet 108 on holding means 107 is de-magnetized by an output signal of drive circuit 112, releasing the holding state of wire 100 (Step 8). Then, pulse motor 33 is driven to permit scale 53 on first carriage 41 1 to be moved to a position corresponding to the set ratio (Step 9). Pulse motor 33 continues to be driven until the above-mentioned position is reached (Step 10). Once this position is reached, pulse motor 33 and thus first carriage 41 1 are stopped (Step 11).
According to this invention, wire 100 for driving above-mentioned indicators 51, 52 is held or gripped by above-mentioned holding means 107 and, in this state, indicators 51, 52 are moved with a movement of first carriage 41 1 . This arrangement requires no conventional dedicated motor for driving above-mentioned indicators 51, 52. According to this invention, it is possible to make the respective component parts and thus the apparatus lower in cost without increasing the number of component parts required.
The image forming apparatus according to another embodiment of this invention will be explained below.
The same reference numerals are employed in FIG. 11 to designate parts or elements corresponding to those in FIGS. 1 to 5 and 7, except for different parts or elements as noted.
FIG. 11 is a view showing the use of, for example, an electromagnetic clutch as an interlocking means. In FIG. 11, indicators 51, 52 are each attached to different parallel runs of wire 100 which is stretched between pulleys 101 and 120 through spring 103. Gear 122 is coupled to pulley 120 through electromagnetic clutch 121 and gear 122 is in mesh with gear 126 through gears 123, 124 and 125. Gear 126 is coupled to idle pulley 44.
In the arrangement shown in FIG. 11, the same flow chart as shown in FIG. 9 is used except that electromagnetic clutch 121 is excited, in place of driving holding means 107, when an image-reproducible range is to be displayed. The flow chart of FIG. 11 is therefore omitted. That is, in order for the image-reproducible range to be displayed, electromagnetic clutch 121 is excited, coupling pulley 120 to gear 122. When in this state first carriage 41 1 is moved in a direction away from indicators 51 and 52 as in the embodiment shown in FIGS. 7 and 8, it is operated in cooperation with wire 100. When indicator 51 is detected by position detector 106, first carriage 41 1 is stopped by the output signal of main processor group 71. Then, first carriage 41 1 is driven toward indicators 51, 52 by the output signal of main processor group 71. When indicators 51 and 52 are moved relative to each other to obtain a distance therebetween corresponding to the set ratio, first carriage 41 1 is stopped. In this state, electromagnetic clutch 121 is de-magnetized by an output signal of drive circuit 112 through main processor group 71. Then, scale 53 is moved to a position corresponding to the set ratio.
Even in this embodiment it is possible to obtain the same advantages as in the embodiment of FIGS. 7 and 8.
Although in this embodiment the electromagnetic clutch has been used as a coupling means, it is not restricted thereto. It may be possible to use, for example, a spring clutch instead.
It is to be understood that various changes and modifications may be made by those skilled in the art without departing from the scope or spirit of this invention.
According to this invention an image forming apparatus is formed which can provide a low-cost display means without increasing the number of component parts required. | An image forming apparatus and method which drives a display device and an optical scanning device to visually depict an image-reproducible range which is set in accordance with a selected magnification/reduction factor. The display device includes two indicators positioned adjacent the original document table and movable with respect to each other to indicate a first dimension on the document table. The optical scanning device includes an indicator which moves relative to the original document table to indicate the second dimension of the image-reproducible range. The apparatus further includes an interlocking device for interlockingly driving the display device with the movement of the optical scanning device. Control circuitry controls the driving of the interlocking device in accordance with the selected magnification/reduction factor and the size of the sheet upon which the copy is made. The control device controls the driving of the interlocking means until the display device is moved to a predetermined position, to permit the display device to interlockingly move with the movement of the optical scanning device. When the display device reaches the predetermined position, the interlocking means is de-energized to permit movement of the optical scanning device only. | 6 |
FIELD OF THE INVENTION
[0001] The invention relates to the synthesis of polymers containing self-complementary quadruple hydrogen groups by copolymerizing monomers containing a quadruple hydrogen bonding group with one or more monomers of choice. The resulting polymers show unique new characteristics due to the presence of additional physical interactions between the polymer chains that are based on multiple hydrogen bonding interactions (supramolecular interactions).
BACKGROUND OF THE INVENTION
[0002] This invention relates to polymers containing units that are capable of forming H-bridges with each other leading to physical interactions between different polymer chains. The physical interactions originate from multiple hydrogen bonding interactions (supramolecular interactions) between self-complementary units containing at least four hydrogen bonds (units capable of forming at least four hydrogen bonds are in this application abbreviated as 4H-units or 4H-monomers and are used in this application as interchangeable terms) in a row. Sijbesma et al. (U.S. Pat. No. 6,320,018; Science, 278, 1601) discloses such self-complementary units which are based on 2-ureido-4-pyrimidones. In Example X the 4H-unit 6-(3-butenyl)-2-butylureido-4-pyrimidone is disclosed. Polymers obtained by polymerization of the carbon-carbon double bond moiety of this compound are, however, not disclosed.
[0003] Telechelic polymers have been modified with 4H-units (Folmer, B. J. B. et al., Adv. Mater. 2000, Vol. 12, 874; Hirschberg et al., Macromolecules 1999, Vol. 32, 2696). However, this has been performed after polymerization in a laborious post-modification process. Another drawback of these polymers containing 4H-units is that they only contain the 4H-unit coupled at the ends of the polymers. Consequently, the number of end groups is therefore limited by the amount of end groups (normally 2), and the functional units are always located on the periphery of the polymer.
[0004] Polymers containing hydrogen bonding groups in the main chain synthesized via copolymerization of hydrogen bonding monomers have been obtained with hydrogen bonding units containing three H-bonds in a row (Lange F. M. et al., Macromolecules 1995, Vol 28, 782). However, only an alternating copolymer of styrene and maleimide can be used in this approach, and moreover, the H-bonding interactions between the polymers are much weaker than the H-bonding based on the 4H-units, obviously resulting in poorer material properties.
[0005] Polymers with quadruple H-bonding units in the main chain have been obtained by copolymerizing 4H-monomers in the main chain of a polyolefin (Coates, G. W. et al., Angew. Chem. Int. Ed., 2001, Vol. 40, 2153). However, complex chemistry has to be used to prepare and to polymerize the monomer and, due to the intrinsic sensitivity of the catalyst needed to obtain the polymer, severe limitations hinder the general use of this system and limits it to tailor-made polyolefin systems. For example, Coates et al. discloses the copolymerization of 1-hexene and a 6-hexenyl-2-ureido-4-pyrimidone derivative with a Ziegler-Natta type nickel based catalyst and diethylaluminum chloride as cocatalyst.
[0006] The present invention discloses a convenient synthesis and convenient copolymerization of monomers containing a 4H-unit with other widely available monomers. The present invention can be used for the preparation of a wide range of polymers with 4H hydrogen bonding units in order to provide these polymers with unique new material properties as a result of the incorporation of the 4H-units. These new material properties result from the reversible nature of H-bonding interactions between the polymer chains that allow reversible changing of the material properties by external stimuli like heat or dilution. Consequently, it becomes possible to prepare materials that combine the mechanical properties of conventional macromolecules with the low melt viscosity of organic compounds.
SUMMARY OF THE INVENTION
[0007] The invention relates to monomers comprising (a) a monomeric unit having a group that can be polymerized (or a monomeric unit having a polymerizable group), (b) a linking moiety and (c) a structural element capable of forming at least four hydrogen bridges, preferably four hydrogen bridges, wherein the monomer has the general structure:
[0008] (a)-(b)-(c).
[0009] The invention further relates to processes for the preparation of these monomers, copolymers comprising these monomers and processes for the preparation of these copolymers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] [0010]FIG. 1. Solution viscosities of PMMA solutions in chloroform at 20° C.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Description of the Monomer Containing the 4H-Unit
[0012] The monomer containing the 4H-unit comprises a group that can be polymerized, a linker and a 4H-unit. In particular, the group that can be polymerized is linked to a 4H-unit via a linker as is shown below in schematic form.
[0013] According to the invention, the monomers comprise (a) a monomeric unit having a group that can be polymerized (i.e. a monomeric unit having a polymerizable group), (b) a linking moiety and (c) a structural element capable of forming at least four hydrogen bridges, preferably four hydrogen bridges, wherein the monomer has the general structure:
[0014] (a)-(b)-(c)
[0015] Preferably, (a) comprises monomeric units having an ethylenically unsaturated group or an ion-polymerizable group. Most preferably, group (a) comprises monomeric units having an ethylenically unsaturated group.
[0016] In general, the structural element that is capable of forming at least four hydrogen bridges has the general form (1′) or (2′):
[0017] If the structural element (c) is capable of forming four hydrogen bridges which is preferred according to the invention, the structural element (c) has preferably the general form (1) or (2):
[0018] In all general forms shown above the C—X i and C—Y i linkages each represent a single or double bond, n is 4 or more and X 1 . . . X n (═X i ) represent donors or acceptors that form hydrogen bridges with the H-bridge-forming monomer containing a corresponding structural element (2) linked to them, with X i representing a donor and Y, an acceptor or vice versa. Properties of the structural element having general forms (1′), (2′), (1) or (2) are disclosed in U.S. Pat. No. 6,320,018 which for the US practice is incorporated herein by reference.
[0019] The structural elements (c) have at least four donors or acceptors, preferably four donors or acceptors, so that they can in pairs form at least four hydrogen bridges with one another. Preferably the structural elements (c) have at least two successive donors, followed by at least two acceptors, preferably two successive donors followed by two successive acceptors, preferably structural elements according to general form (1′) or more preferably (1) with n=4, in which X 1 and X 2 both represent a donor or an acceptor, respectively, and X 3 and X 4 both an acceptor or a donor, respectively. According to the invention, the donors and acceptors are preferably O, S, and N atoms.
[0020] Molecules that can be used to construct the structural element (c) are nitrogen containing compounds that are reacted with isocyanates or thioisocyanates, or that are activated and reacted with primary amines, to obtain a urea moiety that is part of the quadruple hydrogen bonding site. The nitrogen containing compound is preferably an isocytosine derivative (i.e. a 2-amino-4-pyrimidone derivative) or a triazine derivative, or a tautomer of these derivatives. More preferably, the nitrogen containing compound is an isocytosine having an alkyl or oligoethylene glycol group in the 6-position, most preferably methyl, or ethylhexyl. The isocyanates or the thioisocyanates can be monofunctional isocyanates or monofunctional thioisocyanates or bifuntional diisocyanates or bifunctional thioisocyanates (for example alkyl or aryl (di)(thio)isocyanate(s)).
[0021] A particularly suitable structural element (c) according to the invention are the compounds shown below having general formulae (3) or (4), and tautomers thereof:
[0022] The structural element (c) according to formulae (3) or (4), respectively, is bonded to the linking moiety (b) at R 1 , R 2 or R 3 (so that R 1 , R 2 or R 3 represent a direct bond) with the other R groups representing a random side chain or are hydrogen atoms. More preferably, the structural element (c) is bonded to the linking moiety (b) at R 1 (so that R 1 represents a direct bond) whereas R 2 and R 3 are a random side chain or are hydrogen atoms. Most preferably, R 2 is a random side chain and R 3 a hydrogen atom, wherein the random side chain is an alkyl or oligoethylene glycol group in the 6-position, most preferably methyl, or ethylhexyl.
[0023] The linking moiety (b) may be all kinds of shorter or longer chains, for example saturated or unsaturated, branched, cyclic or linear alkyl chains, siloxane chains, ester chains, ether chains and any chain of atoms used in traditional polymer chemistry, whether or not substituted with functional groups such as esters, ethers, ureas or urethanes. Preferably, the linking moiety (b) is a C 1 -C 20 straight chain or branched alkylene, arylene, alkarylene or arylalkylene group, more preferably a C 2 -C 10 straight chain or branched alkylene, arylene, alkarylene or arylalkylene group, wherein the alkylene, arylene, alkarylene or arylalkylene group may be substituted with other groups or may contain cyclic groups as substituent or in the main chain. Examples of such groups are methylene, ethylene, propylene, tetramethylene, pentamethylene, hexamethylene heptamethylene, octamethylene, nonamethylene, 1,6-bis(ethylene)cyclohexane, 1,6-bismethylene benzene, etc. The alkylene, arylene, alkarylene or arylalkylene groups may be interrupted by heteroatoms, in particular heteroatoms selected from the group of oxygen, nitrogen, and sulphur. The linking moiety (b) that links the monomeric unit having a polymerizable group (a) to structural element (c) is derived from a compound that must have at least two functional groups, e.g. hydroxy, carboxylate, carboxylic ester, acyl halide, isocyanate, thioisocyanate, primary amine, secondary amine, or halogen functions. These functional groups are preferably present as end groups. According to the invention, such preferred compounds from which the linking moieties (b) are derived are preferably those having isocyanate or thioisocyanate end groups, more preferably isocyanate end groups. Most preferably, these compounds are diisocyanates or dithioisocyanates, in particular diisocyanates. Examples of suitable diisocyanates that can be used in this invention are:
[0024] 1,4-diisocyanato-4-methyl-pentane,
[0025] 1,6-diisocyanato-2,2,4-trimethylhexane,
[0026] 1,6-diisocyanato-2,4,4-trimethylhexane,
[0027] 1,5-diisocyanato-5-methylhexane,
[0028] 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate,
[0029] 1,6-diisocyanato-6-methyl-heptane,
[0030] 1,5-diisocyanato-2,2,5-trimethylhexane,
[0031] 1,7-diisocyanato-3,7-dimethyloctane,
[0032] 1-isocyanato-1-methyl-4-(4-isocyanatobut-2-yl)-cyclohexane,
[0033] 1-isocyanato-1,2,2-trimethyl-3-(2-isocyanato-ethyl)-cyclopentane,
[0034] 1-isocyanato-1,4-dimethyl-4-isocyanatomethyl-cyclohexane,
[0035] 1-isocyanato-1,3-dimethyl-3-isocyanatomethyl-cyclohexane,
[0036] 1-isocyanatol-n-butyl-3-(4-isocyanatobut-1-yl)-cyclopentane.
[0037] 1-isocyanato-1,2-dimethyl-3-ethyl-3-isocyanatomethyl-cyclopentane,
[0038] 3(4)-isocyanatomethyl-1-methylcyclohexyl isocyanate (IMCI),
[0039] toluene diisocyanate (TDI),
[0040] methylene diphenyl diisocyanate (MDI),
[0041] methylene dicyclohexane 4,4-diisocyanate,
[0042] isophorone diisocyanate (IPDI), hexane diisocyanate (HDI).
[0043] Examples of suitable thioisocyanates are the dithioisocyanate derivatives of the compounds exemplified above for suitable dithiocyanates.
[0044] Preferably, the diisocyanate is IPDI, HDI, MDI, TDI or methylene dicyclohexane 4,4-diisocyanate and their thioisocyanate counterparts. According to the invention, however, the diisocyanates are more preferably used than dithioisocyanates.
[0045] The monomeric unit having a polymerizable group (a) can be any monomeric unit having a polymerizable group. The monomeric unit having a polymerizable group (a) comprises preferably monomeric units having an ethylenically unsaturated group or an ion-polymerizable group and most preferably the monomeric unit having a polymerizable group comprises a monomeric unit having an ethylenically unsaturated group, i.e. a group derived from monomers having a carbon carbon double bond. According to a preferred embodiment of the invention, the monomeric unit having a polymerizable group has at least one functional group such as hydroxy, carboxylic acid, carboxylic ester, acyl halide, isocyanate, thioisocyanate, primary amine, secondary amine or halogen groups. According to a more preferred embodiment of the invention, the monomeric unit having a polymerizable group is derived from acrylates, methacrylates, acrylamides, methacrylamides, styrenes, vinyl-pyridines, other vinyl monomers, lactones, other cyclic esters, lactams, cyclic ethers and cyclic siloxanes. According to the most preferred embodiment of the invention, the monomeric unit having a polymerizable group is derived from acrylates, methacrylates, acrylamides, methacrylamides and vinyl esters, most preferably vinyl acetates. Examples of compounds from the monomeric units having a polymerizable group that are in particular useful in carrying out the invention are: 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2,3-dihydroxypropyl acrylate, poly(ethylene glycol) acrylate, N-hydroxymethyl acrylamide, 2-hydroxyethyl methacrylate, 2-hydroxy-propyl methacrylate, 2,3-dihydroxypropyl methacrylate, poly(ethylene glycol) methacrylate, N,N-dimethylaminoethylmethacrylate, N-hydroxymethyl methacrylamide, vinylacetate, 4-hydroxymethyl-styrene, 4-aminomethyl-styrene, hexahydro-7-oxo-1H-azepine-4-carboxylic acid and 2,3-epoxy-1-propanol.
[0046] According to the invention, the monomers are preferably prepared by the following methods.
[0047] According to a first method, the monomeric unit having a polymerizable group is reacted in a first step with the compound that must have at least two functional groups. In a subsequent step, the product obtained in the first step is reacted with the nitrogen containing compound. Suitable and preferred structures of the monomeric unit having a polymerizable group, the compound that must have at least two functional groups and the nitrogen containing compound are described above.
[0048] According to a second method, the nitrogen containing compound is reacted in a first step with the compound that must have at least two functional groups. In a subsequent step, the product obtained in the first step is reacted with the monomeric unit having a polymerizable group.
[0049] According to a third method, the nitrogen containing compound is reacted directly with the monomeric unit having a polymerizable group wherein the monomeric unit is able to form a urea linkage between both reactants.
[0050] According to these methods, the monomeric unit having a polymerizable group is most preferably selected from the group of monomeric units having an ethylenically unsaturated group, in particular monomers having a carbon carbon double bond, wherein the monomeric unit having a polymerizable group has preferably at least one functional group, wherein the functional group is selected from the group of hydroxy, carboxylic acid, carboxylic ester, acyl halide, isocyanate, thioisocyanate, primary amine, secondary amine or halogen groups. More preferably, the monomeric unit having a polymerizable group is selected from the group of acrylates, methacrylates, acrylamides, methacrylamides, styrenes, vinyl-pyridines, other vinyl monomers, lactones, other cyclic esters, lactams, cyclic ethers and cyclic siloxanes having a functional group selected from hydroxy, carboxylic acid, carboxylic ester, isocyanate, thioisocyanate, primary amine, secondary amine or halogen groups. Even more preferably, the monomeric unit having a polymerizable group is selected from the group of acrylates, methacrylates, acrylamides, methacrylamides, and vinyl esters, in particular vinyl acetates, said acrylates, methacrylates and vinyl esters having preferably a functional group selected from hydroxy, carboxylic acid, carboxylic ester, acyl halide, isocyanate, thioisocyanate, primary amine, secondary amine or halogen groups.
[0051] Preferred embodiments of the methods for the preparation of the monomers are shown below in Schemes 1-3.
[0052] wherein R 2 and R 3 are as defined above, R 4 is hydrogen or methyl, A is a chain, preferably an oligomethylene chain or an oligoethylene glycol chain (as will be understood and appreciated by the person skilled in the art, A may be absent so that the monomeric unit having a polymerizable group has a carboxylic group as functional group. Similarly, instead of the acrylic/methacrylic acid moieties shown in Schemes 1 and 2, their corresponding amide moieties be used) and B is the chain of the linking moiety (b) described above.
[0053] In Scheme 3 R 6 and R 7 represent each independently a C 1 -C 6 alkyl group, wherein R 7 is preferably methyl.
[0054] Description of the Co-Polymerization and of the Polymer
[0055] The polymers presented in this invention are obtained by co-polymerizing the monomer containing the 4H-unit with one or more, optionally different comonomers that can be from the same family or from a different family of monomers. These comonomers are preferably selected from the group of: acrylic acid; C 1 -C 30 branched or linear alkyl esters of acrylic acid; methacrylic acid; C 1 -C 30 branched or linear alkyl esters of methacrylic acid; acrylamides or methacrylamides wherein the amide group may be substituted with one or two C 1 -C 30 branched or linear alkyl groups; vinyl esters, preferably vinyl acetates; other compounds having a vinyl group wherein said compounds are preferably selected from pyrrolidones, imidazoles, pyridines, caprolactams, piperidones, benzene and derivatives thereof; C 4 -C 20 alkadienes; lactones; lactams; and saturated or unsaturated heterocyclic compounds containing one to five oxygen atoms. Examples of suitable comonomers are acrylic acid, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, N,N-dimethylacrylamide, N-isopropylacrylamide, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, 2-hydroxy-ethyl methacrylate, vinylacetate, N-vinylpyrrolidinone, 2-vinylpyridine-1-oxide, N-vinyl imidazole, N-vinyl pyridine, N-vinylcaprolactam, N-vinyl-2-piperidone, acrylonitrile, styrene, butadiene, isoprene, caprolacton, butyrolacton, caprolactam, ethyleneoxide, propyleneoxide, tetrahydrofuran, 3,6-dimethyl-1,4-dioxane-2,5-dione, 1,4-dioxane-2,5-dione.
[0056] The copolymerizations may be of any type (for example, bulk, dispersion, solution, emulsion, suspension or inverse phase emulsion) and of any mechanism (for example, radical polymerization, condensation polymerization, transition metal catalyzed polymerization or ring opening polymerization).
[0057] The copolymer backbone acquired may be of any type (linear, branched, star, hyperbranched, dendritic, comb-like or the like).
[0058] The product copolymer may be of any structure. For example random, regular, tapered or block copolymer structures are allowed.
[0059] According to the invention, the molecular weight of the polymers are preferably not too high. A preferred number average molecular weight range is 500-50000.
[0060] The copolymers according to the invention are in particular suitable for applications related to personal care (hair preparations, skin cosmetics and laundry aids), surface coatings (leather, textile, optical fibers, paper and paint formulations), imaging technologies (printing, stereolithography, photography and lithography), biomedical applications (materials for controlled release of drugs and materials for tissue-engineering), tablet formulation, adhesive and sealing compositions, and thickening agent and binders.
EXAMPLES
[0061] The following examples describe:
[0062] (i) the synthesis of building blocks that are needed to synthesize the monomers and polymers that are presented in these examples;
[0063] (ii) the synthesis of monomers that contain the 4H hydrogen bonding unit. Easy to produce methacrylates are described, as well as an acrylate monomer and an acrylamide monomer;
[0064] (iii) the copolymerization of various 4H bonding containing monomers with monomers such as HEMA (hydroxy ethylmethacrylate) or MMA (methyl methacrylate). Several examples deal with the co-polymerization of three monomers, one of which has a pendant 4H bonding unit. As polymerization techniques, ATRP and AIBN radical polymerization procedures are given. Different molecular weights of polymers are obtained, as well as different levels of incorporation of the 4H hydrogen bonding unit; and
[0065] (iv) a comparison between the solution viscosity in chloroform of two PMMA samples of comparable molecular weight: one of the PMMA samples is prepared by ATRP copolymerization of MMA with a monomer containing a 4H-bonding unit, the other sample is PMMA prepared by ATRP homopolymerization of MMA. This example illustrates that properties of polymers—in this case the solution viscosity can be deviated strongly when pending 4H hydrogen bonding units are incorporated.
[0066] (i) The Synthesis of Building Blocks
Example 1
Synthesis of an Isocyanate Synthon
[0067] [0067]
[0068] 1,6-Hexyldiisocyanate (650 g) and methyl-isocytosine (or 2-amino-4-hydroxy-6-methyl-pyrimidine, 65.1 g) were suspended in a 2-liter flask. The mixture was stirred overnight at 100° C. under an argon atmosphere. After cooling to room temperature, a liter of pentane was added to the suspension, while stirring was continued. The product was filtered, washed with pentane and dried in vacuum. A white powder was obtained. 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (1H), 11.8 (1H), 10.1 (1H), 5.8 (1H), 3.3 (4H), 2.1 (3H), 1.6 (4H), 1.4 (4H). IR (neat): ν 2935, 2281, 1698, 1668, 1582, 1524, 1256.
Example 2
Synthesis of the ATRP Initiator Benzyl 2-bromo-2-methyl-propionate
[0069] [0069]
[0070] 2-Bromo-2-methylpropionyl bromide (6.8 mL) was diluted with dichloromethane and added to a solution of triethylamine (7.7 mL) and benzyl alcohol (4.8 mL), while the mixture was cooled in an ice bath and while maintaining an argon atmosphere. The solution was stirred for one hour at 0° C. and then overnight at room temperature. Volatiles were evaporated and the residue was treated with diethylether. The formed salt was removed by filtration and the filtrate was washed with an HCl solution and with water. The ether solution was dried with MgSO 4 and concentrated to yield a yellowish liquid. Silica column chromatography using a 2/1 hexane/ethyl acetate mixture as eluent gave a colourless transparent liquid. 1 H NMR (400 MHz, CDCl 3 ): δ 7.4 (5H), 5.3 (2H), 2.0 (6H).
Example 3
Synthesis of 6-(1-ethylpentyl)-isocytosine
[0071] [0071]
[0072] Potassium ethyl malonate (150 g) and acetonitrile (1.4 L) were stirred in a flask and brought to a temperature of 10-15° C. Triethylamine (132 mL) was added drop wise, while keeping the mixture under an argon atmosphere. Dried MgCl 2 (101.6 g) was added and the suspension was stirred for 2 hours at room temperature. Thereafter, the suspension was cooled to 0° C. and 2-ethylhexanoyl chloride (74 mL) was added drop wise, and the mixture was allowed to warm up to room temperature and was stirred overnight. The acetonitrile was removed by evaporation, 400 mL toluene was added and evaporated, 700 mL of toluene was added and the mixture was cooled to 10° C. An aqueous HCl solution was added slowly, and the organic layer was separated, washed with an HCl solution and then with a bicarbonate solution. The organic layer was dried with Na 2 SO 4 and concentrated to give the β-ketoester as a liquid. The β-ketoester (50 g) and guanidine carbonate (49.8 g) were boiled in ethanol (300 mL) for two days using a Soxhlett set-up with molsieves in the thimble. The suspension was filtered, ethanol was evaporated and the product was dissolved in chloroform. After washing with a bicarbonate solution, the organic layer was dried with MgSO 4 , concentrated and dropped into an excess of pentane to yield a white powder. 1 H NMR (400 MHz, CDCl 3 ): δ 11.6-10.6 (1H), 7.6-6.6 (2H), 5.6 (1H), 2.2 (1H), 1.5 (4H), 1.2 (4H), 0.8 (6H). IR (neat): ν 3322, 3152, 2929, 2860, 1635, 1463, 1378, 1582, 1524.
[0073] (ii) Synthesis of 4H Hydrogen Bonding Unit Containing Monomers
Example 4
Monomer 1, a 4H Hydrogen Bonding Unit Containing Methacrylate Monomer
[0074] [0074]
[0075] The isocyanate (79 g) was suspended in chloroform (1.5 L), and thereafter hydroxy ethyl methacrylate (HEMA, 64 mL) and 15 drops of dibutyl tin dilaurate (DBTDL) were added. The mixture was stirred at an oil bath temperature of 90° C. for 4 hours, and was then cooled and filtered. The filtrate was concentrated and dropped into an excess of diethylether. The white precipitate was collected by filtration, and was washed with diethylether. Drying in vacuo gave a white solid product (90 g). 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (1H), 11.8 (1H), 10.1 (1H), 6.1 (1H), 5.8 (1H), 5.6 (1H), 5.0 (1H), 4.3 (4H), 3.3-3.2 (4H), 2.1 (3H), 1.9 (3H), 1.7-1.2 (8H). IR (neat): ν 3301, 2932, 1720, 1699, 1685, 1665, 1582, 1525, 1258.
Example 5
Monomer 2, a 4H Hydrogen Bonding Unit Containing Acrylate Monomer
[0076] [0076]
[0077] The isocyanate (46 g) was suspended in chloroform (1 L), and thereafter hydroxy ethyl acrylate (HEA, 36 mL) and 10 drops of dibutyl tin dilaurate (DBTDL) were added. The mixture was stirred at an oil bath temperature of 90° C. for 4 hours, and was then cooled and filtered. The filtrate was concentrated and an excess of diethylether was added. The white precipitate was collected by filtration, and was washed with diethylether. Drying in vacuo gave a white solid product. 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (1H), 11.8 (1H), 10.1 (1H), 6.5 (1H), 6.2 (1H), 5.9 (2H), 5.1 (1H), 4.4 (4H), 3.3 (2H), 3.2 (2H), 2.1 (3H), 1.7-1.3 (8H). IR (neat): ν 3307, 2928, 1725, 1702, 1682, 1664, 1584, 1548, 1258, 1192.
Example 6
Monomer 3, a 4H Hydrogen Bonding Unit Containing Methacrylate Monomer
[0078] [0078]
[0079] 2-Isocyanatoethyl methacrylate (7.0 mL) was added to a solution of 6-(1-ethylpentyl)isocytosine (13.4 g) in dry pyridine (150 mL). The reaction mixture was stirred under an argon atmosphere at 80° C. for 4 hrs. The product was isolated by evaporation of the solvent, and subsequent filtration over silica using chloroform/methanol (4%). Silica column chromatography using ethyl acetate/hexane yielded a light yellowish waxy solid. 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (1H), 12.0 (1H), 10.5 (1H), 6.2 (1H), 5.8 (1H), 5.6 (1H), 4.3 (2H), 3.6 (2H), 2.3 (1H), 1.9 (3H), 1.8-1.5 (4H), 1.4-1.2 (4H), 0.9 (6H). IR (neat): ν 2959, 2930, 1720, 1697, 1645, 1582, 1555, 1525, 1462, 1254, 1160.
Example 7
Monomer 4, a 4H Hydrogen Bonding Unit Containing Methacrylate Monomer
[0080] [0080]
[0081] The PEG-MA monomer (an average molecular weight of 306; 2.2 g), the isocyanate (1.8 g) and a few drops of DBTDL were boiled overnight in chloroform. Hexane was added to cause precipitation. The product was isolated by filtration, washing with hexane and with diethyl ether. 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (1H), 11.8 (1H), 10.1 (1H), 7.2 (1H), 6.0 (1H), 5.7 (1H), 5.6 (1H), 4.2 (2H), 4.0 (2H), 3.7 (2H), 3.6-3.4 (15H-20H), 3.1 (2H), 2.9 (2H), 2.1 (3H), 1.9 (3H), 1.4 (4H), 1.2 (4H).
Example 8
Monomer 5, a 4H Hydrogen Bonding Unit Containing Acrylamide Monomer
[0082] [0082]
[0083] The isocyanate (1 g) was dissolved in 5 mL of acrylic acid and heated to 70° C. The mixture was stirred under an argon atmosphere. Copper(II)acetate (8 mg) was added and heating at 70° C. was maintained for 2 days. The product was obtained by precipitation of the reaction mixture into diethylether. The solid was isolated by filtration, and was dissolved in chloroform. The organic solution was washed with a bicarbonate solution and dried with Na 2 SO 4 . Filtration and concentration of the filtrate gave a white powder. 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (1H), 11.8 (1H), 10.1 (1H), 6.4-6.0 (3H), 5.8 (1H), 5.6 (1H), 3.4-3.2 (4H), 2.1 (3H), 1.7-1.2 (8H). IR (neat): ν 3278, 2935, 1699, 1665, 1652, 1582, 1525.
[0084] (iii) Co-Polymerizations
[0085] A TRP (Atom Transfer Radical Polymerization) Procedures
[0086] Typical A TRP Co-Polymerization Experiment
[0087] A 25 mL round bottom flask containing the appropriate amounts of CuBr, bipyridine and 4H hydrogen bonding unit containing monomer was degassed (de-oxygenated) by vacuum followed by argon backfill, and repeating this cycle twice. The other monomer(s) and the solvent were degassed (de-oxygenated) by bubbling through argon for at least 45 minutes prior to addition of these liquids to the 25 mL flask by use of a syringe. The reaction mixture was stirred until all components had dissolved (sometimes after short warming) to produce a homogeneous dark brown solution. The reaction flask was placed in a water bath that was maintained at room temperature, and finally, the ATRP-initiator was added using a syringe. Polymerization occurred immediately, leading to an increase in viscosity of the reaction mixture.
[0088] Samples were taken at regular intervals to assess the extent of polymerization by 1 H NMR spectroscopy. On exposure to air, the dark brown sample solutions turned blue, indicating aerial oxidation of Cu(I) to Cu(II). After the polymerization was complete, the polymer was recovered by precipitation into an appropriate non-solvent.
[0089] The applied ATRP polymerization procedure allows that 1 H NMR spectroscopy can be used to determine certain features of the isolated polymer: the M n of the polymer can be determined by comparing the integral of the benzylic signals of the polymer end group to the integral of the monomeric unit signals. Additionally, 1 H NMR can be used to calculate the average number of 4H hydrogen bonding units per polymer chain by considering the integral of the benzylic signals of the polymer end group and the integral of the alkylidene signal of the 4H hydrogen bonding unit.
Example 9
PHEMA with Pendant 4H Hydrogen Bonding Units by ATRP Copolymerization of HEMA and Monomer 1
[0090] [0090]
[0091] A 25 mL round bottom flask containing 0.14 g of CuBr, 0.354 g of bipyridine, and 0.853 g of monomer 1 were degassed by vacuum followed by argon backfill (3 times). Degassed DMSO (4.7 mL) and hydroxyethylmethacrylate (HEMA, 4.7 mL) were added via a syringe. The reaction flask was placed in a water bath at room temperature and stirred to produce a dark brown solution. Finally, 0.255 g of initiator was added prompting immediate polymerization. After half an hour of reaction, the polymer was recovered by precipitation into chloroform and drying of the precipitate.
[0092] [0092] 1 H NMR analysis verified that monomer 1 was co-polymerized into the polymer product: it showed that the co-polymerization produced PHEMA with a molecular weight M n of approximately 10 kD and with ca. 1.7 pendant 4H hydrogen bonding units per polymer chain. 1 H NMR (400 MHz, DMSO-d 6 ): δ 7.4 (phenyl), 5.8 (alkylidene monomer 1), 5.1 (benzylic methylene), 3.9, 3.6, 2.1 (methyl monomer 1), 2.0-0.6.
Example 10
PHEMA with Pendant 4H Hydrogen Bonding Units by ATRP Co-Polymerization of HEMA, PEG-MA and Monomer 3
[0093] [0093]
[0094] A 25 mL round bottom flask containing 0.31 g of CuBr, 0.70 g of bipyridine and 1.51 g of monomer 3 was degassed by vacuum followed by argon backfill (3 times). Degassed DMSO (5 mL), hydroxyethylmethacrylate (HEMA, 5 mL) and polyethyleneglycol methacrylate (PEG-MA, FW average =306, 1.14 g) were added via a syringe. The reaction flask was placed in a water bath at room temperature and stirred to produce a dark brown solution. Finally, 0.56 g of initiator was added prompting immediate polymerization. After half an hour of reaction, the polymer was recovered by precipitation into an EDTA (25 g/L) solution in water and drying of the precipitate.
[0095] Yield: 6.25 g.
[0096] [0096] 1 H NMR analysis verified that monomer 3 was co-polymerized into the polymer product: it showed that the co-polymerization produced PHEMA with a molecular weight M n of approximately 5 kD and with 1.5-2.0 pendant 4H hydrogen bonding units per polymer chain. SEC (0.01 M LiBr in DMF) showed an M n of 18 kD and a polydispersity of D=1.8, as compared to polystyrene standards. Polystyrene does not dissolve well in the used eluent, so these numbers are overrated. 1 H NMR (400 MHz, DMSO-d 6 ): 7.4 (phenyl), 5.8 (alkylidene monomer 3), 5.1 (benzylic methylene), 3.9, 3.7-3.2, 2.0-0.6.
Example 11
PHEMA with Pendant 4H Hydrogen Bonding Units by ATRP Co-Polymerization of HEMA, PEG-MA and Monomer 3
[0097] [0097]
[0098] A 25 mL round bottom flask containing 0.144 g of CuBr, 0.272 g of bipyridine and 0.70 g of monomer 3 was degassed by vacuum followed by argon backfill (3 times). Degassed DMSO (5 mL), hydroxy ethylmethacrylate (HEMA, 5 mL) and polyethyleneglycol methacrylate (PEG-MA, FW average =306, 0.55 mL) were added via a syringe. The reaction flask was placed in a water bath at room temperature and stirred to produce a dark brown solution. Finally, 0.254 g of initiator was added prompting immediate polymerization. After 35 minutes of reaction, the polymer was recovered by precipitation into an EDTA (25 g/L) solution in water and drying of the precipitate.
[0099] Yield: 5.75 g.
[0100] [0100] 1 H NMR analysis verified that monomer 3 was co-polymerized into the polymer product: it showed that the co-polymerization produced PHEMA with a molecular weight M n of approximately 10 kD and with ca. 2.5 pendant 4H hydrogen bonding units per polymer chain. SEC (0.01 M LiBr in DMF) showed an M n of 27 kD and a polydispersity of D=1.6, as compared to polystyrene standards. Polystyrene does not dissolve well in the used eluent, so these numbers are overrated. 1 H NMR (400 MHz, DMSO-d 6 ): δ 7.4 (phenyl), 5.8 (alkylidene monomer 3), 5.1 (benzylic methylene), 3.9, 3.7-3.2, 2.0-0.6.
Example 12
PHEMA with Pendant 4H Hydrogen Bonding Units by ATRP Co-Polymerization of HEMA and Monomer 3
[0101] [0101]
[0102] A 25 mL round bottom flask containing 0.062 g of CuBr, 0.179 g of bipyridine and 0.60 g of monomer 3 was degassed by vacuum followed by argon backfill (3 times). Degassed DMSO (2 mL) and hydroxyethylmethacrylate (HEMA, 2 mL) were added via a syringe. The reaction flask was placed in a water bath at room temperature and stirred to produce a dark brown solution. Finally, 0.114 g of initiator was added prompting polymerization. After 35 minutes of reaction, the polymer was recovered by precipitation into an EDTA (25 g/L) solution in water and drying of the precipitate.
[0103] [0103] 1 H NMR analysis verified that monomer 3 was co-polymerized into the polymer product: it showed that the co-polymerization produced PHEMA with an M n of ca. 10 kD and with ca. 3.5-4.0 pendant 4H hydrogen bonding units per polymer chain. 1 H NMR (400 MHz, DMSO-d 6 ): δ 7.4 (phenyl), 5.8 (alkylidene monomer 3), 5.1 (benzylic methylene), 3.9, 3.7-3.2, 2.0-0.6.
Example 13
PHEMA with Pendant 4H Hydrogen Bonding Units by ATRP Co-Polymerization of HEMA and Monomer 4
[0104] [0104]
[0105] A 25 mL round bottom flask containing 0.062 g of CuBr, 0.134 g of bipyridine and 0.51 g of monomer 4 was degassed by vacuum followed by argon backfill (3 times). Degassed DMSO (2 mL) and hydroxyethylmethacrylate (HEMA, 2 mL) were added via a syringe. The reaction flask was placed in a water bath at room temperature and stirred to produce a dark brown solution. Finally, 0.115 g of initiator was added prompting immediate polymerization. After half an hour of reaction, the polymer was recovered by precipitation into an EDTA (25 g/L) solution in water and drying of the precipitate.
[0106] [0106] 1 H NMR analysis verified that monomer 4 was co-polymerized into the polymer product: it showed that the co-polymerization produced PHEMA with a molecular weight M n of approximately 6-7 kD and with ca. 1.5 pendant 4H hydrogen bonding units per polymer chain. 1 H NMR (400 MHz, DMSO-d 6 ): δ 7.4 (phenyl), 7.2 (amide monomer 4) 5.8 (alkylidene monomer 4), 5.1 (benzylic methylene), 3.9, 3.7-3.2, 2.20.6.
Example 14
PMMA with Pendant 4H Hydrogen Bonding Units by ATRP Co-Polymerization of MMA and Monomer 3
[0107] [0107]
[0108] A 25 mL round bottom flask containing 0.134 g of CuBr and 0.51 g of monomer 3 was degassed by vacuum followed by argon backfill (3 times). Degassed toluene (5 mL) and methyl methacrylate (MMA, 5 mL) were added via a syringe. The mixture was stirred at 60° C. to acquire a homogeneous solution. Pentamethyldiethylene triamine (PMDETA, 0.20 mL) was added, so that a light green solution was obtained. Finally, 0.185 mL of ATRP initiator was added prompting polymerization. After 150 minutes, the reaction mixture was diluted in chloroform and filtered over silica. The filtrate was concentrated, dissolved in toluene and precipitated into hexane.
[0109] [0109] 1 H NMR analysis verified that monomer 3 was copolymerized into the polymer product: it showed that the co-polymerization produced PMMA with a molecular weight M n of approximately 11 kD and with ca. 2.0-2.5 pendant 4H hydrogen bonding units per polymer chain. SEC (chloroform) showed an M n of 12.5 kD and a dispersity of D=1.6 (data versus polystyrene standards). 1 H NMR (400 MHz, CDCl 3 ): δ 13.1 (monomer 3), 12.1 (monomer 3), 10.5 (monomer 3), 7.4 (phenyl), 5.9 (alkylidene monomer 3), 5.1 (benzylic methylene), 4.1 (monomer 3), 3.7-3.5, 2.1-1.6, 1.2-0.8.
Example 15
PMMA by ATRP Polymerization of MMA
[0110] [0110]
[0111] A 25 mL round bottom flask containing 0.138 g of CuBr was degassed by vacuum followed by argon backfill (3 times). Degassed methyl methacrylate (MMA, 5.2 mL) was added via a syringe. Then pentamethyldiethylene triamine (PMDETA, 0.20 mL) was added, and the mixture was stirred and brought to 60° C. Finally, 0.185 mL of ATRP initiator was added prompting polymerization. After 30 minutes, the reaction mixture was diluted in chloroform and filtered over silica. The filtrate was concentrated, dissolved in toluene and precipitated into hexane.
[0112] [0112] 1 H NMR (400 MHz, CDCl 3 ): δ 7.4 (phenyl), 5.1 (benzylic methylene), 3.7-3.5, 2.1-1.7, 1.6-0.8. 1 H NMR analysis showed that PMMA with a molecular weight M n of approximately 11 kD was prepared. SEC (chloroform) showed an M n of 15 kD and a dispersity of D=1.45 (data versus polystyrene standards).
[0113] AIBN Radical Polymerization Procedures
[0114] Typical Procedure
[0115] A solution of HEMA, 4H hydrogen containing monomer, AIBN and transfer agent in DMF was degassed by purging with argon for 1 hr prior to polymerization was commenced. After the reaction time at a certain temperature, the mixture was cooled down to room temperature and the polymer was recovered by precipitation into an appropriate non-solvent, filtration and drying.
Example 16
PHEMA with Pendant 4H Hydrogen Bonding Units by AIBN Radical Co-Polymerization of HEMA and Monomer 3
[0116] [0116]
[0117] A mixture of HEMA (4.7 mL), monomer 3 (0.725 g), DMF (30 mL), mercaptoethanol (0.02 mL) and AIBN (11.3 mg) in a dropping funnel was degassed by bubbling through of argon for an hour. Then, the mixture was dropped into a flask that was immersed in an oil bath of 60° C. After addition, the mixture was stirred for two days. After one day a second batch of AIBN (11.3 mg) was added The polymer was precipitated into THF/hexane 3:1 and dried in a vacuum stove. NMR verified that monomer 3 was co-polymerized into the polymer product. 1 H NMR (400 MHz, DMSO-d 6 ): δ 5.8 (alkylidene monomer 3), 4.0-3.8, 3.7-3.4, 2.0-0.6.
Example 17
PHEMA with Pendant 4H Hydrogen Bonding Units by AIBN Radical Co-Polymerization of HEMA and Monomer 3
[0118] [0118]
[0119] In a mixture of HEMA (5 mL), monomer 3 (0.4 g), DMF (15 mL), mercaptoethanol (0.060 mL) and AIBN (12 mg) in a flask were degassed by bubbling through of argon for an hour. Then, the flask was immersed in an oil bath of 80° C. for 4 hours. The polymer was precipitated into THF/hexane 3:1 and dried in a vacuum stove. SEC with UV-detection verified that monomer 3 was co-polymerized into the polymer product. Other SEC data (0.01 M LiBr in DMF), M n =24 kD, D=1.4, data versus polystyrene standards.
Example 18
Solution Viscosity Measurements
[0120] The PMMA polymers prepared by ATRP polymerization that have been described in examples 14 and 15 are of approximately the same molecular weight as 1 H NMR and SEC analyses attest. The only difference between the PMMA polymers is that the one described in example 14 has pending 4H hydrogen bonding units. FIG. 1 depicts the solution viscosities of PMMA solutions in chloroform at 20° C.
[0121] The solution (kinematic) viscosity of the PMMA with pending 4H hydrogen bonding units is much more dependent on the concentration as that of the regular PMMA. The difference is caused by extra 4H hydrogen bonding interactions between the PMMA chains. This example illustrated that the introduction of 4H hydrogen bonding units to polymers can drastically alter the behavior of these polymers, giving rise to unique properties. | The invention relates to the synthesis of polymers containing self-complementary quadruple hydrogen groups by copolymerizing monomers containing a quadruple hydrogen bonding group with one or more monomers of choice. The resulting polymers show unique new characteristics due to the presence of additional physical interactions between the polymer chains that are based on multiple hydrogen bonding interactions (supramolecular interactions). | 1 |
This is a continuation of application Ser. No. 08/004,881 filed on Jan. 19, 1993 abandoned which is a C-I-P of Ser. No. 07/823,525 filed Jan. 21, 1992 abandoned and a C-I-P of Ser. No. 07/916,819 filed Jul. 20, 1992 now U.S. Pat. No. 5,403,444 which is a C-I-P of Ser. No. 07/489,427 filed Mar. 5, 1990 now U.S. Pat. No. 5,133,835.
FIELD OF THE INVENTION
This invention generally relates to synthetic paper made on conventional continuous wet-lay papermaking equipment. In particular, the invention relates to recyclable polymeric synthetic paper made of 100% polymeric material.
The invention also relates to labels, especially to labels adapted for use in labeling of blow-molded plastic containers. In particular, the label comprises a coated 100% synthetic web prepared by a wet-lay process. The label may be applied either in-mold or post-mold to a blow-molded container made of the same synthetic material as the main synthetic fiber component (for example, polyethylene, polyester or polypropylene) of the label with or without the use of an adhesive material and may be recycled along with the container.
BACKGROUND OF THE INVENTION
It is conventional practice to make synthetic paper using synthetic pulp comprising short fibers of polyethylene. Such synthetic paper is made using polyethylene pulp with or without cellulose fibers. Such flexible polymeric synthetic substrates are used to make water-resistant cardboard, embossed paper, heat-sealing paper, battery separators, felt mats, hygienic absorbents and building materials. To meet the demands of various applications, many grades of polyethylene have become commercially available. These synthetic pulp products use polyethylenes of different physical properties. Polypropylene and polypropylene/polyethylene products are also known.
U.S. Pat. No. 5,047,121 to Kochar discloses a process for making synthetic paper containing at least 97 wt. % polyethylene on conventional continuous wet-lay papermaking equipment. The process includes the steps of: (1) preparing a pulp furnish comprising 97-99.5 wt. % polyethylene fibers and 0.5-3.0 wt. % polyvinyl alcohol binder fibers; (2) depositing the pulp furnish on the screen of a wet-lay papermaking machine to form a waterleaf sheet; (3) drying the resulting waterleaf sheet on heated drying cans having a drying profile wherein an initial drying phase is provided at a temperature between 200° F. and 270° F. to melt the polyvinyl alcohol fibers and a second drying phase is provided at a temperature between 190° F. and 240° F. to control stretch and elongation of the sheets; and (4) thermally bonding the dried sheet at a temperature between 250° F. and 315° F. to provide polyethylene paper. The thermal bonding can be accomplished with a calendar roll. The Kochar patent teaches that: (1) the strength of the synthetic paper can be tailored by varying the amount of polyvinyl alcohol fibers mixed into the polyethylene pulp; and (2) the porosity of the synthetic paper can be tailored by varying the bonding temperature.
In accordance with the teaching of the Kochar patent, the polyethylene pulp is fused to a degree dependent on the thermal bonding temperature. This results in a polyethylene paper which is suitable for the specific applications identified in that patent, i.e., filtration applications (e.g., vacuum cleaner bags) and battery separators. However, the low opacity of the resulting paper makes it unsuitable for use in high-quality printing. This is because the application of too much heat for a long duration causes the polyethylene pulp to flow to such a degree that it becomes increasingly translucent as it approaches a polyethylene film in structure.
Paper made of 100% synthetic fibers is useful as label paper. For example, the in-mold labeling of blow-molded plastic containers is less costly than conventional labeling methods in which labels with adhesive backing are adhered to the container in a separate step subsequent to blow molding. In-mold labeling eliminates this separate step, thereby reducing labor costs associated with handling of the adhesive-backed labels and capital costs associated with the equipment used to handle and apply adhesive-backed labels.
In accordance with conventional in-mold labeling of blow-molded plastic containers, labels are sequentially supplied from a magazine and positioned inside the mold by, for example, a vacuum-operated device. Plastic material is then extruded from a die to form a parison as depicted in FIG. 6 of U.S. Pat. No. 4,986,866 to Ohba et al., the description of which is specifically incorporated by reference herein. The mold is locked to seal the parison and then compressed air is fed from a nozzle to the inside of the parison to perform blow molding wherein the parison is expanded to conform to the inner surface of the mold. Simultaneously with the blow molding, the heat-sealable layer of the label of Ohba et al. is pressed by the outer side of the parison and fused thereto. Finally, the mold is cooled to solidify the molded container and opened to obtain a labeled hollow container.
For the sake of efficiency, it is desirable that the labeling of blow-molded containers be conducted continuously and rapidly. Also the labels to be applied during in-mold labeling should be sufficiently stiff that the automatic equipment used to handle the labels does not cause wrinkling or folding thereof. Conversely, the labels must be sufficiently elastic that they neither tear nor separate from the plastic container during flexing or squeezing of the latter.
A further disadvantage of conventional in-mold labels prepared from paper is that prior to recycling of the plastic container, the paper label must be removed using either solvent or mechanical means to avoid contamination of the recycled plastic material by small pieces of paper.
One prior art attempt to grapple with this recycling problem is disclosed in U.S. Pat. No. 4,837,075 to Dudley, which teaches a coextruded plastic film label for in-mold labeling of blow-molded polyethylene containers. The label comprises a heat-activatable ethylene polymer adhesive layer and a surface printable layer comprising polystyrene. The heat activatable adhesive substrate layer comprises a polyethylene polymer. Pigment or fillers are incorporated in the polystyrene layer to provide a suitable background for printing. An example of a suitable pigment is titanium dioxide and an example of a suitable filler is calcium carbonate. Preferably a layer is interposed between the adhesive substrate and the surface printable layer that comprises reground and recycled thermoplastic material used to prepare such labels. The label stock is prepared by coextrusion of the various label layers utilizing conventional coextrusion techniques. Separately applied adhesive is not employed.
The aforementioned patent to Ohba et al. teaches a synthetic label for in-mold labeling of blow-molded resin containers comprising a thermoplastic resin film base layer and a heat-sealable resin layer having a melting point lower than that of the thermoplastic resin base layer. The base layer has an inorganic filler, such as titanium dioxide or calcium carbonate, incorporated therein or incorporated in a latex coating thereon. The base layer may, for example, be high-density polyethylene or polyethylene terephthalate. The heat-sealable resin layer may, for example, be low-density polyethylene. The heat-sealable resin layer serves to firmly adhere the label to a resin container. In accordance with the preferred embodiment of the Ohba et al. label material for use on a blow-molded container made of polyethylene, four separate layers are joined together by coextrusion.
U.S. Pat. No. 5,006,394 to Baird teaches a polymeric film structure having a high percentage of fillers, for example, opacifying or whitening agents such as titanium dioxide and calcium carbonate. The fillers are concentrated in a separate filler containing layer coextruded with a base layer. The base layer may comprise polyolefins (for example, polyethylenes), polyesters or nylons. The filler-containing layer may comprise any of the same polymeric materials, but preferably comprises ethylene vinyl acetate coploymer. However, this film material is intended for use in disposable consumer products such as diapers.
In addition, U.S. Pat. No. 4,941,947 to Guckert et al. discloses a thermally bonded composite sheet comprising a layer of flash-spun polyethylene plexifilamentary film-fibril strand sheet in face-to-face contact with a layer of polyethylene synthetic pulp suitable for use in bar code printing. The layer of polyethylene synthetic pulp is formed by conventional wet-lay papermaking techniques.
The Dudley and Ohba et al. patents both disclose an in-mold label having a multiplicity of layers coextruded together. This complexity of structure raises the costs of manufacturing the respective in-mold label materials. Although there is no suggestion in the Baird patent that the film material disclosed therein would be suitable for use as in-mold label paper, if it were usable for that purpose it would suffer from the same disadvantage of being a relatively complex laminated structure and therefore relatively costly to manufacture. Likewise the patent to Guckert et al. discloses a laminated structure.
SUMMARY OF THE INVENTION
The present invention improves upon the prior art by providing a flexible polymeric synthetic nonwoven substrate which is suitable for use as lint-free writing paper, labels on plastic bottles, release liner, specialty packaging paper or filter paper. In particular, one preferred embodiment of the invention is a high-opacity polymeric synthetic nonwoven substrate suitable for use in high-quality printing applications.
In addition, the polymeric synthetic paper of the invention contains no cellulosic fibers and therefore can be easily recycled without costly procedures for separating polymeric and cellulosic materials. In particular, it is an object of the invention to provide a synthetic paper which does not leave behind any foreign material to be screened out when the paper is melted.
The synthetic paper in accordance with the invention can be used as labels on polymeric containers, for example, labels for blow-molded polymeric containers, which need not be removed prior to recycling of the polymeric containers. Such labels sufficiently elastic to withstand flexing and squeezing of the plastic container without tearing or separating therefrom. Also the nonwoven label of the invention is more porous than film labels, which enhances the printability of the label, and is cheaper to manufacture.
In accordance with the invention, the synthetic paper comprises a nonwoven web of fibers, at least one side of which has a pigmented coating, e.g., a pigment-containing latex. The paper is manufactured from commercially available fibers. The components may be combined in water into a homogeneous mixture and then formed into a web employing a wet-lay process.
In accordance with a first preferred embodiment, the fiber composition of the web is 88-100% polyethylene pulp and 0-12% polyvinyl alcohol binder fibers. In a variation of this embodiment, the web comprises 70-100% polyethylene pulp, 0-12% polyvinyl alcohol binder fibers and 0-30% polypropylene fibers. Polypropylene pulp can be substituted for all or any portion of the polyethylene pulp.
In accordance with another preferred embodiment, the fiber composition of the web is 50-90% chopped polyester staple fibers, 10-40% bicomponent polyester/co-polyester core/sheath binder fibers and 0-10% polyvinyl alcohol binder fibers bonded together. Each bicomponent binder fiber comprises a core of polyester surrounded by a co-polyester sheath.
In both preferred embodiments, the nonwoven web of fibers is made more printable by saturation with a binder material, for example, with an ethylene vinyl acetate latex or other suitable latex having a glass transition temperature (T g ) of 0-30° C. The latex is preferably compounded to contain pigment such as calcium carbonate, titanium dioxide or both at pigment/binder ratios of 0.5/1 to 8/1, resulting in a synthetic paper having a surface suitable for high-quality printing thereon. However, the use of a latex binder, as opposed to other conventional binders, is not required to practice the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing the production line for making up the stock for use in manufacturing the synthetic paper in accordance with the invention;
FIG. 2 is a diagram showing the production line for making synthetic paper in accordance with the invention from the stock make-up output by the apparatus of FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with the invention, synthetic paper is formed from a web of synthetic fibers with no cellulosic fibers. The synthetic fibers may be made of polyethylene, polyester, polypropylene or any other polymeric material suitable for use in high-opacity paper.
In accordance with a first preferred embodiment, the web comprises 88-100% polyethylene fibers and 0-12% polyvinyl alcohol fibers and is coated with an ethylene vinyl acetate latex or other suitable latex having a glass transition temperature (T g ) of 0-30° C. and compounded to contain pigment such as calcium carbonate, titanium dioxide, clay, talc or other inorganic pigments as known to those skilled in the art. The coating may contain any conventional binder other than latex.
The synthetic paper in accordance with the invention is manufactured from commercially available fibers such as polyethylene pulp, polypropylene pulp, chopped polyester staple fibers and polyvinyl alcohol binder fibers. The components may be combined in water into a homogeneous mixture and then formed into a mat employing a wet-lay process.
In accordance with a first example of a polyethylene-based synthetic paper, the starting fiber materials consist of 90 wt. % Mitsui 9400 Fybrel™ polyethylene pulp commercially available in the United States from Minifibers, Route 14, Box 11, Johnson City, Tenn. 37615 and 10 wt. % Kuraray 105-2 polyvinyl alcohol (PVA) binder fibers commercially available in the United States from Itochu Corp., 335 Madison Avenue, New York, N.Y. 10017. In Mitsui 9400 Fybrel™ polyethylene pulp the polyethylene fibers have an average length of 0.90 mm and a diameter of 15 microns. Kuraray 105-2 PVA binder fibers have an average length of 5 mm and a denier of 2.0.
In accordance with a second example of a polyethylene-based synthetic paper, the starting fiber material may be 100 wt. % Mitsui 9400 Fybrel™ polyethylene pulp, that is, PVA binder fibers are not essential to practice of the invention. In this embodiment, the polyethylene pulp is entangled during the wet lay process to form the base sheet. Optionally, the base sheet may thereafter be coated with the pigmented binder—avoiding thermal fusion of the polyethylene pulp—to produce a high-opacity synthetic paper having excellent printability.
Alternatively, in accordance with a variation of the polyethylene-based synthetic paper, some of the Kuraray 105-2 PVA binder fibers are replaced by 10 mm×2.2 denier Hercules Herculon™ polypropylene staple fibers. These polypropylene staple fibers are commercially available in the United States from Hercules, Inc., 3169 Holcomb Bridge Road, Suite 301, Norcross, Ga. 30071. In accordance with this variation the web is comprised of 70-100% polyethylene fibers, 0-12% PVA fibers and 0-30% polypropylene fibers. One example of this variation successfully made by the inventors had 85% polyethylene fibers, 7.5% PVA fibers and 7.5% polypropylene fibers.
In all of the foregoing variations, polypropylene pulp can be substituted for the polyethylene pulp.
After the base mat has been dried, it is preferably treated with a coating comprised of a binder, e.g., latex, pigmented with calcium carbonate, titanium dioxide, clay, talc or other inorganic pigment to enhance the printability of the paper. The surface treatment may be applied with any commercially available coater, treater or size press. Thereafter the web can be machine calendared to give the coating a predetermined surface smoothness.
In accordance with the preferred embodiment of the coating applied to the above-described webs, the starting coating materials are 50 wt. % Vinac 884 ethylene vinyl acetate latex and 50 wt. % Albagloss calcium carbonate. Alternatively, Airflex 4514 ethylene vinyl acetate/ethylene vinyl chloride copolymer latex can be used in place of the Vinac 884 ethylene vinyl acetate latex, although the latter is preferred. The Vinac 884 and Airflex 4514 latexes are commercially available in the United States from Air Products and Chemicals, Polymers and Chemicals Division, 5100 Tilghman Street, Allentown, Pa. 18104. The Albagloss calcium carbonate is commercially available in the United States from Pfizer, Inc., Minerals, Pigments and Metals Division, 640 North 13th Street, Easton, Pa. 18042-1497.The range of calcium carbonate incorporated in the coating can be varied from a pigment/binder ratio of 0.5/1 to 8/1, although the preferred ratio is 1/1.
The synthetic paper in accordance with the invention can be made on standard papermaking equipment. The process for making label paper prepared from a web of polyethylene pulp, PVA binder fibers and polypropylene staple fibers is described hereinafter with reference to FIGS. 1 and 2, which show the stock make-up equipment 8 and the papermaking equipment 10 , respectively.
The Fybrel™ 9400 polyethylene pulp is loaded in a fiber opening chest 12 at consistencies between 2% and 5% solids. The pulp is agitated until it is completely dispersed in water and no fiber bundles are apparent. This mixture is then pumped to a blend chest 18 via a deflaker 16 . In the deflaker the fibers are subjected to fiber-to-fiber agitation which removes any fiber bundles or unopened clumps. The def laker is preferable to a disk refiner in that no cutting or shortening of the fibers occurs.
At the same time a predetermined amount of Kuraray 105-2 PVA binder fibers and, optionally, a predetermined amount of polypropylene staple fibers are loaded in a fiber opening chest 14 at consistencies between 0.5% and 5% solids in hot water. The PVA binder fibers become gelatinous in hot water. The dispersion is agitated until the staple fibers are completely dispersed in water and no fiber bundles are apparent. This mixture is then pumped into blend chest 18 . Alternatively, no pump is needed if the mixture is dropped by gravity into blend chest 18 . The binder and staple fiber dispersion is added to the furnish so that the PVA binder fibers and the staple fibers make up 0-12 wt. % and 0-30 wt. % of the furnish solids, respectively. The mixture is agitated to achieve a uniform dispersion of the polyethylene pulp, staple fibers and gelatinous PVA having a consistency between 1% and 5% solids.
The furnish is then pumped by pump 20 to the refiner 22 , which beats the fibers as needed to reduce their average length. The refined furnish then enters a surge chest 24 , where it is mixed with the broke furnish from broke pulper 26 .
Broke is synthetic paper that has been rejected during the process of manufacture. Broke may take the form of either “wet” broke or “dry” broke. Wet broke is synthetic paper taken off the wet press of the paper machine. Dry broke is paper spoiled when passing through the dryers or the calendar, trimmed off in the rewinding of rolls, trimmed from sheet being prepared for shipping or rejected for manufacturing defects.
In accordance with the process of the invention, the broke is loaded in the broke pulper 26 at consistencies between 1% and 5% solids. The broke furnish is agitated by high-shear agitator 28 until the broke fibers are completely dispersed in water and no fiber bundles are apparent. The broke furnish is then pumped to surge chest 24 via a deflaker 30 in a controlled manner to maintain consistency and limit the percent of broke addition to not exceed 20% of the total volume. The refined furnish and the broke furnish are mixed in surge chest 24 until a uniform dispersion is achieved.
The furnish in surge chest 24 is then pumped via pump 32 into machine chest 34 , which feeds its contents into the forming section while maintaining a constant level in the chest to reduce variation in product weight. The final stock is pumped to the papermaking machine (see FIG. 2) by pump 36 .
Before the stock is made into synthetic paper, large contaminants (such as dirt, gravel, pieces of kraft bags, sand and grit) and fiber bundles are removed from the stock by screening in primary and secondary cleaners 38 and 40 . Material containing rejected debris is fed to the secondary cleaners from the primary stage. Rejects from the secondary stage are sewered while accepts are sent back to the main feed stream. This is a way to concentrate the rejects and save fiber.
The furnish is supplied to the headbox 42 at consistencies between 0.1% and 1% solids. A web of synthetic fibers is then formed on standard wet-lay papermaking equipment by forming wire 44 . Excess water is removed by gravity and vacuum devices. The formed web is wet-pressed in press section 46 and then dried in the first dryer section 48 at a temperature in the range of 140° F. to 260° F. to remove more water.
During drying, the polymeric fibers are not fused, but rather the gelatinous PVA becomes a glue which pre-bonds the polyethylene pulp and staple fibers into a web. (For applications where high strength is not a requirement, PVA is unnecessary. For example, 100% polyethylene pulp entangled by the wet-lay process has adequate strength to be fed to the saturator/coater.) When drying the web, care must be taken to ensure that the web and dryer can temperatures remain below the melting point of the polyethylene fibers, that is, below 269° F. (132° C.). Otherwise the opacity of the synthetic paper will be degraded. The use of release coating on the dryer cans was found to be beneficial in preventing buildup or sticking that will eventually cause web defects and/or breaks.
Thereafter the dried web is saturated with ethylene vinyl acetate latex solution containing calcium carbonate pigment. This treatment may be performed on a paper machine size press or any type of off-line coater or treater 50 which is supplied with saturant from mixing chest 52 . The coating is applied to the web in an amount that achieves a 10 wt. % add-on of dried coating solids, that is, 200 lbs/ton, although it will be recognized by the person skilled in the art that the weight percentage of dried coating solids can be varied over a wide range. The coating is then dried in the second dryer section 54 , again at a temperature in the range of 140° F. to 260° F., whereby the ethylene vinyl acetate bonds the fibers to each other and bonds the pigment to the fibers. Excessive heat is to be avoided during saturation because the latex coagulates when exposed to excessive heat, leading to latex build-up on the rolls. After the coating is dried, the coated web is machine calendared in calendar 56 to attain a surface smoothness (Sheffield) of 125-250 units and is then wound on winding reel 58 .
The physical properties of synthetic paper made from 90% polyethylene pulp and 10% PVA binder fibers in accordance with the invention are listed in Table I.
TABLE I
Physical Property Test Data
TAPPI
Physical
Uncoated
Finished
No.
Property
Base Sheet
Coated Sheet
410
Basis Weight (3300 ft 2 )
45.0
50.0
(oz./yd 2 )
2.2
2.4
411
Caliper (mils)
8.8
8.0
251
Porosity-Permeability
<0
<0
Frazier Air (cfm)
460
Gurley Porosity (sec/100 cc)
10
22
538
Sheffield Smoothness (T/W)
—
200/260
403
Mullen Burst (psi)
—
5
414
Elmendorf Tear (g) (MD/CD)
—
25/31
511
MIT Fold (MD/CD)
—
2/0
494
Tensile (lbs/in.) (MD/CD)
4.1/2.4
5.6/2.8
494
Elongation (%) (MD/CD)
—
4.3/6.5
494
TEA (ft-lb/ft 2 ) (MD/CD)
—
2.1/1.6
452
GE Brightness (%)
93.3
93.9
425
Opacity (%)
97.1
96.6
413
Ash (%) (500° C.)
0.0
3.0
In accordance with another preferred embodiment of the invention, the web comprises chopped polyester staple fibers, bicomponent polyester/co-polyester core/sheath binder fibers and PVA binder fibers. Each bicomponent binder fiber comprises a core of polyester surrounded by a co-polyester sheath. After the wet-laid sheet has been dried, the dried base sheet is thermal-bonded at a predetermined temperature and a predetermined pressure to bond the fibers on both surfaces of the sheet and impart strength. The sheet is then coated with an ethylene vinyl acetate latex having a glass transition temperature (T g ) of 0-30° C. Again the latex may be compounded to contain pigment such as calcium carbonate, titanium dioxide, clay, talc or other inoraganic pigments at pigment/binder ratios of 0.5/1 to 8/1. Because synthetic paper in accordance with these embodiments has no cellulosic fibers, the synthetic paper may be recycled without going through a separation process.
In accordance with a first example of the polyester-based synthetic paper of the invention, the starting fiber materials are 77 wt. % Kuraray polyester chopped strand, 19 wt. % Kuraray N-720 polyester/co-polyester core/sheath binder fibers and 4 wt. % Kuraray 105-2 PVA binder fibers. All of these fibers are commercially available in the United States from Itochu Corp., 335 Madison Avenue, New York, N.Y. 10017. The Kuraray chopped polyester staple fibers have an average length of 10 mm and a denier of 0.4. Kuraray N-720 polyester/co-polyester core/sheath binder fibers have an average length of 10 mm and a denier of 2.0. Kuraray 105-2 PVA binder fibers have an average length of 5 mm and a denier of 2.0.
In accordance with a second example of the polyester-based synthetic paper of the invention, the starting fiber materials are 80 wt. % Kuraray polyester chopped strand and 20 wt. % Kuraray N-720 polyester/co-polyester core/sheath binder fibers. No Kuraray 105-2 PVA binder fibers are used.
Alternatively, an equal weight percent of Teijin polyester staple fibers having an average length of 5 mm and a denier of 0.5 can be substituted for the Kuraray chopped polyester staple fibers in the polyester-based synthetic paper. In accordance with other variations, an equal weight percent of polyethylene pulp can be substituted for the PVA binder fibers.
In accordance with yet another variation, the polyester chopped staple fibers can be combined with either PVA binder fibers or polyester/co-polyester core/sheath binder fibers or with both, but only in an amount sufficient to hold the web together as it is fed to a thermal calendar. The thermal calendar then fuses the polyester chopped staple fibers using rolls heated to temperatures of 360-410° F. (preferably 390° F.) and nip pressures of 40 psi or greater (preferably 50 psi). The resulting base sheet may be optionally coated with pigmented binder as disclosed above.
The fiber composition of the polyester-based synthetic paper is not limited to the specific weight percentages of the examples described above. The amount of PVA binder fibers may be varied from 0 to 10 wt. %; the amount of co-polyester/polyester sheath/core binder fibers may be varied from 0 to 40 wt. %; and the amount of polyester staple fibers may be varied from 50 to 90 wt. %. Furthermore, the average length and the denier of the chopped polyester staple fibers may vary from 5 to 12 mm and from 0.4 to 1.5 denier respectively; and the average length and the denier of the co-polyester/polyester sheath/core binder fibers may vary from 5 to 12 mm and from 2.0 to 6.0 denier respectively.
In accordance with the coated versions of the second preferred embodiment, the starting coating materials are 50 wt. % Vinac 884 ethylene vinyl acetate latex and 50 wt. % Albagloss calcium carbonate. Alternatively, Airflex 4514 ethylene vinyl acetate/ethylene vinyl chloride copolymer latex can be used in place of the Vinac 884 ethylene vinyl acetate latex, although the latter is preferred. The range of calcium carbonate incorporated in the coating can be varied from a pigment/binder ratio of 0.5/1 to 8/1, although the preferred ratio is 1/1. The glass transition temperature T g of the ethylene vinyl acetate latex may vary from 0° C. to 30° C.
The web material in accordance with the second preferred embodiment can be made on standard papermaking or nonwoven fabric equipment. The polyester cut staple fibers, the polyester/co-polyester core/sheath binder fibers and the polyvinyl alcohol binder fibers are added to water undergoing agitation and containing a predissolved surfactant material, such as Milease T, at a level of 0.5% based on polyester fiber weight. Milease T is commercially available from I.C.I. Americas, Inc.
The foregoing fiber components should be added to the blend chest in the following sequence: (1) polyvinyl alcohol binder fibers, (2) polyester/co-polyester core/sheath binder fibers and (3) chopped polyester staple fibers. The consistency of the mixture in the blend chest should be between 0.5 and 2.5% solids. An anionic polyacrylamide such as 87P061 may be added at levels in the range 0.5-8.0 lbs/ton based on fiber weight to aid in fiber dispersion. 87P061 is commercially available from Nalco Chemical. The mixture is then agitated to attain a uniform dispersion of all materials. The refining step and broke recovery can be bypassed for the second preferred embodiment.
The resulting furnish is then formed on standard wet-lay papermaking equipment at headbox consistencies of 0.7-0.01%. The wet-laid material is then dried in the dryer section.
The dried web is calendared between smooth metal rolls heated to a temperature of 196° C. The web is calendared at minimal pressure, that is, 50-150 PLI, to achieve bonding of the surface fibers while maintaining the degree of opacity of the original sheet.
This material is then ready to be treated with the ethylene vinyl acetate latex solution pigmented with calcium carbonate. As noted above, the treatment may be applied on a paper machine size press or any type of off-line coater or saturator. The coating is applied in a manner that results in a 10 wt. % add-on of dried coating solids, that is, 200 lbs/ton. The coating is then dried. After the coating is dried, the coated web is supercalendared to attain a surface smoothness (Sheffield) of 125-250 units.
The physical properties of the label paper in accordance with the first example of the second preferred embodiment of the invention are listed in Table II.
TABLE II
Physical Property Test Data
Un-
coated
Thermally
Finished
TAPPI
Physical
Base
Bonded
Coated
No.
Property
Sheet
Sheet
Sheet
410
Basis Weight (3300 ft 2 )
45.0
45.0
51.3
411
Caliper (mils)
15.6
4.8
7.9
251
Porosity-Permeability
192
13
38
Frazier Air (cfm)
451
Taber V-5 Stiffness
1.9/1.4
1.1/0.9
4.2/2.5
(gcm) (MD/CD)
403
Mullen Burst (psi)
13
126
183
414
Elmendorf Tear (g)
233/261
229/168
184/138
(MD/CD)
511
MIT Fold (MD/CD)
3/6
2500+/2500+
2500+/2500+
494
Tensile (lbs/in.)
4.7/4.6
25.0/25.0
33.2/43.2
(MD/CD)
494
Elongation (%) (MD/CD)
1.4/2.2
11.2/10.7
12.3/15.8
494
TEA (ft-lb/ft 2 ) (MD/CD)
0.7/1.3
32.9/32.1
40.4/72.9
452
GE Brightness (%)
82.5
86.9
85.6
425
Opacity (%)
69.0
74.2
76.5
Tests were conducted to determine the effect of PVA binder level on the strength of the synthetic paper made from polyethylene pulp. The results of those tests are shown in Table III. The results show that the tear and tensile strengths of the synthetic paper are better at a 7.5 wt. % PVA binder fiber level than at 4 or 11 wt. %.
TABLE III
Effect of Polyvinyl Alcohol Level
Physical
PVA Level
Property
4%
7.5%
11%
Basis Weight (GMS/m 2 )
77
78
72
Caliper (mils)
7.6
7.8
7.7
Gurley Porosity (sec/100 cc)
24
19
16
Mullen Burst (psi)
10
11
6
Elmendorf Tear (g) (MD/CD)
39/51
45/51
37/45
MIT Fold (MD/CD)
16/3
23/10
11/4
Tensile (lbs/in.) (MD/CD)
5.3/3.8
6.3/4.1
5.3/3.1
GE Brightness (%)
95.2
95.0
94.3
Opacity (%)
93.9
93.5
91.9
Tabe IV shows the effect of adding a 10-mm-long polypropylene staple fiber to the furnish. The three samples tested had the following compositions: (A) 90% Mitsui 9400 polyethylene pulp, 10% PVA binder fiber and 0% staple fiber; (B) 90% Mitsui 9400 polyethylene pulp, 0% PVA binder fiber and 10% staple fiber; and (C) 85% Mitsui 9400 polyethylene pulp, 7.5% PVA binder fiber and 7.5% staple fiber. Tear strength is improved as the result of adding staple fiber and the improvement is maximized when a binder fiber is included. Porosity increases as the level of higher-diameter fiber (the binder fiber and the staple fiber) increases. This is one way in which sheet porosity can be controlled when designing synthetic papers for applications where either minimal porosity or a specific level of porosity is required.
TABLE IV
Effect of Staple Fiber Addition
Physical
Sample
Property
A
B
C
Basis Weight (GMS/m 2 )
67
85
67
Caliper (mils)
9
11
9
Porosity (sec/100 cc)
18
12
13
Tear Strength (g) (MD/CD)
26/30
39/39
51/55
Table V shows the effect of coating or size press applications of a binder. The main effect being designed to is the surface strength so that the web can be printed on without the surface being damaged from the tacky ink on the printing plate. The IGT number shows the improvement when a coating is applied. (IGT is a standard laboratory printing test wherein if the material is weak in the direction perpendicular to the sheet, it will pull apart or large sections of the surface will be pulled out.) A carefully formulated coating can also decrease porosity. Stiffness can be increased or left unchanged by careful selection of the binder.
Thus, in accordance with the invention the porosity of the synthetic paper can be controlled by carefully adjusting the coating formulation and by adjusting the amount of staple fibers.
TABLE V
Effect of Coating
Physical
Uncoated
Finished
Property
Base Sheet
Coated Sheet
Basis Weight (GSM)
60
80
Caliper (mils)
6
7
Mullen Burst (psi)
4
9
Tensile (lbs/in.) (MD/CD)
3.5/2.5
6/5
Gurley Porosity (sec/100 cc)
13
22
Brightness (%)
95
95
Opacity (%)
93
93
IGT
0
115
Elongation (%)
6/8
13/15
Gurley Stiffness (mgf) (MD/CD)
28/20
35/35
The synthetic paper of the invention can be used in labeling of blow-molded plastic containers. In particular, the label may be applied either in-mold or post-mold to a blow-molded container made of the same synthetic material as the main synthetic fiber component (for example, polyethylene, polyester or polypropylene) of the label with or without the use of an adhesive material and may be recycled along with the container.
In accordance with conventional in-mold labeling of blow-molded plastic containers, labels are sequentially supplied from a magazine and positioned inside the mold by, for example, a vacuum-operated device. Plastic material is then extruded from a die to form a parison as depicted in FIG. 6 of U.S. Pat. No. 4,986,866 to Ohba et al., the description of which is specifically incorporated by reference herein. The mold is locked to seal the parison and then compressed air is fed from a nozzle to the inside of the parison to perform blow molding wherein the parison is expanded to conform to the inner surface of the mold. Simultaneously with the blow molding, the heat-sealable layer of the label of Ohba et al. is pressed by the outer side of the parison and fused thereto. Finally, the mold is cooled to solidify the molded container and opened to obtain a labeled hollow container.
A disadvantage of conventional in-mold labels prepared from paper is that prior to recycling of the plastic container, the paper label must be removed using either solvent or mechanical means to avoid contamination of the recycled plastic material by small pieces of paper.
Although the invention has been described with reference to certain preferred embodiments, it will be appreciated that it would be obvious to one of ordinary skill in the art of fiber technology and papermaking that other polymeric fibers could be used to achieve the same beneficial results. In particular, fibers other than polyethylene pulp and polyester chopped staple fibers can be used as the main fiber component. For example, polyester pulp could be used in place of polyester chopped staple fibers in the event that polyester pulp becomes commercially available. Further, suitable polymeric fibers having a melting point lower than that of the main fiber component can be substituted for PVA binder fibers. For example, polyethylene pulp could be used in place of PVA binder fibers in the polyester-based synthetic paper. Nor is the invention limited to the use of a specific coating binder: suitable coating binders other than ethylene vinyl acetate latex and ethylene vinyl acetate/ethylene vinyl chloride copolymer latex can be used. Also it would be obvious to one of ordinary skill that the preferred embodiments could be readily modified to meet specific conditions not disclosed here. All such variations and modifications are intended to be within the scope and spirit of the invention as defined in the claims appended hereto. | A high-opacity cellulose-free synthetic paper is formed from a wet-laid nonwoven web of thermoplastic fibers, all or most of which fibers are made of a predetermined polymeric material. The wet-laid web is dried to remove excess water, drying being carried cut at temperatures below the melting temperature of the predetermined polymeric material. The dried nonwoven web is saturated on at least one side with a pigmented binder forming a continuous coating thereon. The binder is cured at temperatures below the melting temperature of the predetermined polymeric material. | 3 |
BACKGROUND OF THE INVENTION
This invention relates to building insulation and more particularly to such insulation for use particularly in floors above crawl spaces, garages and basements of heated buildings.
It is common practice to insulate buildings with batts of fibrous insulating material, such as glass wool and the like, to which a vapor barrier layer is applied on one side thereof, as is well known. Proper installation of these batts requires that they be installed with the vapor barrier layer facing the heated area, i.e., the inside of the building structure.
The vapor barrier layer of these batts is provided with fastening lips or flanges in the form of elongated extended edge portions running along the length of the batts on the opposite sides thereof. When it is desired to install the batts in the walls of buildings it is merely necessary to insert them in place between the wall studs and secure the flanges to the studs by nails or building staples. This is a very simple and quick operation to accomplish since the vapor barrier layer is installed away from the outer wall of the building. i.e., closest to the inner wall to be installed over the insulation batt.
The use of such batts for insulating the floor over a crawl space or basement, however, presents several difficulties. Since the vapor barrier layer should be installed facing upward, it is extremely difficult to nail or staple the fastening flanges thereof to the overhead floor joists because the insulating material fills the space between the joists. Accordingly, it has become a not-uncommon practice by workmen to install the batts so the vapor barrier layer thereof faces downward so they can quickly and easily staple the fastener flanges to the floor joists. This, of course, places the vapor barrier layer in the improper position, whereby it "encloses" the insulating material of the batt between the barrier layer and the inside atmosphere of the building. This results eventually in the formation of condensation in the insulating material, thus substantially reducing its effectiveness as a heat insulator.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved unitary building insulation structure which can be rapidly and efficiently installed between the joists of a floor-like horizontal structure.
Another object of this invention is to provide a means for installing insulation in a substantially horizontal position in an easy manner and in accordance with proper building practice.
Still another object of the invention is to provide improved batts of insulation for use between the joists of a floor-like structure whereby the vapor barrier layer faces upward and whereby the fibrous insulation material is held in place by an underneath supporting means which will allow relatively uniform support along the length of the batt to prevent sagging thereof.
Yet another object of the invention is to make it easier for workers to install insulation in batting form in the proper manner in the floor above a crawl space or basement area, whereby condensation in the insulating material resulting from "reverse vapor layer" installation is avoided.
In accordance with the above objectives, one embodiment of my invention provides for a unitary insulation structure comprising a layer of heat insulating material having a layer of relatively thin material on one side thereof for restricting the passage of water vapor therethrough and on the other side a flexible reticulated support material. When installed between the beams or joists of a floor-like structure, the reticulated support material is at the bottom of the unitary insulation structure and provides a uniform support for the insulation layer thereof. In another embodiment of the invention the reticulated support material may be provided not as an integral part of the unitary insulation structure, but rather as a separate support material in order to prevent sagging of conventional insulating material held in place thereby by providing uniform support therefor.
DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the invention will be more readily understood from the following description when taken in conjunction with the accompanying drawings in which like numerals indicate like parts and in which:
FIG. 1 is a fragmentary perspective view of one manner of installing an insulation batt between floor joists according to one prior art technique;
FIG. 2 is a view similar to FIG. 1 but showing the construction and installation of a unitary insulation structure or batt in accordance with one embodiment of this invention;
FIG. 3 is a cross-sectional view of the insulation structure of FIG. 2 taken along line 3--3 thereof;
FIG. 4 is a plan view of the structure of FIG. 2 viewed from underneath the floor in which it is installed;
FIG. 5 illustrates one of the batts shown in FIGS. 2, 3 & 4 in rolled up form for storage and shipping;
FIGS. 6 and 7 are cross-sectional and plan views respectively, similar to FIGS. 3 and 4, of another embodiment of the invention;
FIGS. 8 and 9 are cross-sectional and plan views respectively, also similar to FIGS. 3 and 4, of still another embodiment of the invention; and
FIG. 10 is a perspective view of a still further embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now particularily to FIG. 1, there is shown a floor 10 above a crawl space or basement and supported by joists 14 between which is installed insulation 16 in the form of batts of standard width fibrous material of a type well known in the prior art and which may be made of glass wool or the like. These batts usually include a vapor barrier layer 18 made of tarpaper or other suitable material and secured by any appropriate adhesive during manufacture to the insulation material 16. The vapor barrier layer 18 is provided with fastening flanges 20 whereby nails or staples 22 are used to secure the batt in position between the joists 14. It will be appreciated that the specific insulation as just described and as seen in FIG. 1 is improper because the vapor barrier 18 is on the lower side of the insulation batts, rather than the upper side as is done in accordance with good building practice. While this is not done by all builders, it is however, practiced sufficiently widely to be of concern to those in the building industry.
In accordance with one embodiment of the invention I provide an improved unitary insulation structure and installation therefor as seen in FIGS. 2, 3, and 4 which facilitates proper installation of the insulating material in the floor above a crawl space or basement. Thus in FIGS. 2, 3 and 4 the vapor barrier layer 18 is provided in the proper position on the upper surface of the insulation material 16, rather than on the lower surface thereof as in FIG. 1. The insulation material 16 is supported by a reticulated support member 24, which is preferably non-metallic and may be in the form of a plastic fish net-like material. The member 24 may be made of a variety of materials and in a variety of shapes, but should be relatively flexible. The member 24 in this embodiment is secured to the insulation material 16 by fastening means such as glue, clips or other suitable securing device, at the points indicated by the numerals 26. The entire unitary insulation structure comprising the insulation material 16, vapor barrier layer 18 and support member 24 is secured in place between the joists 14 by means of the staples 22 driven into the joists through fastening flanges 28, which are provided as an integral part of the support member 24.
FIG. 5 shows one of the batts seen in FIGS. 2, 3 and 4, rolled up to illustrate the manner in which the fastening flanges 28 are folded securely within the roll between the layer of insulating material 16 and the vapor barrier layer 18. It will be seen that the improved unitary insulation structure of this invention allows the formation of a roll suitable for stacking one upon another for storage and also suitable for shipping without the precautions and shipping modifications necessary with some of the insulation materials found in the prior art.
In FIGS. 6 and 7 there are shown cross-sectional and plan views, respectively, similar to FIGS. 3 and 4, of another embodiment of the invention. In FIGS. 6 and 7 the fastener flanges are provided in the shape of right angle flanges 28a integral with the reticulated support member 24 and which may be secured to the insulation material 16 in the manner the webbing portion of the member 24 is secured thereto as set forth in the description of FIGS. 2, 3 and 4 above. Additional transverse and longitudinal supporting sections 30 and 32 respectively, are also provided, as best seen in FIG. 7, to provide more adequate support for the insulation material 16 for certain applications.
FIGS. 8 and 9 illustrate in cross-section and plan views respectively, similar to FIGS. 3 and 4, yet another embodiment of the invention. In these figures a batt of insulation material 16 with its vapor barrier layer 18, is shown enclosed within an elongated envelope 34 of flexible reticulated support material of the type best seen in FIG. 4 and installed between the two joists 14. The envelope 34 may be formed by wrapping it around the insulation material 16 in the manner of wrapping a package, and securing the meeting edges as by the small clips 36 or gluing them to the vapor barrier layer 18. Alternatively if desired, instead of wrapping the reticulated support material to form the envelope 34 around the insulation material 16, it may be provided as a preformed circumferentially continuous envelope into which the insulation material is placed to form the structure illustrated in FIGS. 8 and 9. Using this envelope-type construction, it is not necessary to secure the envelope 34 to the insulation material 16 or to the vapor barrier layer 18, as described in connection with FIGS. 3 and 4. With this embodiment it will be appreciated that the unitary insulation structure batts can be installed by using building staples 22 to tack the individual strands of the envelope 34 of reticulated support material to the joists 14 at the point of contact therebetween.
In FIG. 10 there is shown yet a further embodiment of the unitary insulation structure of this invention. In this embodiment a reticulated support member 37, having longitudinally extending flanges 38, is wrapped around the bottom 16a and also the vertical edges 16b of the insulation material 16. These flanges 38 are secured, as by glue or other suitable fastening means, to the vapor barrier layer 18 at the points 40 along the peripherial edge regions of this layer, thus forming an envelope around the insulating material 16. The reticulated member 37 also includes fastening flanges 42, which may be integral therewith, for fastening the batt to its adjacent joists.
It will be appreciated that the embodiment of FIG. 10 provides a relatively rugged unitary insulation batt which can be handled easily and without fear of being too easily damaged and which can be installed by means of the flanges 42 in a rapid, efficient and convenient manner. This construction is therefore extremely cost effective to install and of course, makes it impossible for workmen to install the batts improperly with the vapor barrier layer 18 in the downward position. It will also be appreciated that, if desired, to reduce the cost of manufacture, the construction of FIG. 10 could be modified to eliminate the installation flanges 42 and installation could still be performed with staples around the individual strands of the recticulated member 37 where they meet the joists, as is done with the arrangement of FIGS. 8 and 9.
The flanges, however, are preferable since they make it possible for the workmen to carry out installation of the batts in an extremely rapid manner, particularily when done with staple guns of the type used in the building industry.
It will be further appreciated that the novel reticulated support member of this invention may be provided as a separate item and used with conventional insulation batts of material to support the same in place between the flooring joists. While ordinary plastic-type netting may be used for the reticulated support member, it would be preferable to provide it in the general form indicated by the numeral 24 in FIGS. 2, 3 and 4, i.e., with the fastening flanges 28 as an integral part thereof, in order to facilitate more speedy installation of the batts. With this modification it will also be clear that the fastening of the member 24 to the insulation 16, as indicated by the numeral 26 in FIGS. 2, 3 and 4, is unnecessary and therefore need not be carried out.
Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope therof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. | Building insulation for installation between joists above a crawl space, basement or garage area comprising a layer of insulating material having a vapor barrier layer on the top thereof and a flexible reticulated member at the bottom thereof, such member having fastening flanges thereon extending downwardly and adapted to be secured to the sides of the joists, whereby the reticulated member supports the insulating material and vapor barrier layer. | 4 |
BACKGROUND OF THE INVENTION
FIG. 1 shows a wheeled travel bag equipped with a pulling handle. The pulling handle comprises a fixed mounting rod 2 fixedly mounted on the travel bag, a ball knob 6 raised from the top end of the fixed mounting rod 2, and a drag rod 1 having a ball socket 5 at one end coupled to the ball knob 6 (see FIG. 1A). The ball knob 6 and the ball socket 5 form a universal joint by which the drag rod 1 can be turned in different directions relative to the fixed mounting rod 2 (see FIG. 1B). This structure of carrying handle is still not satisfactory in function. Because the drag rod 1 is coupled to the fixed mounting rod 2 by a universal joint, the drag rod 1 cannot be firmly retained at the desired angle. When pushing the travel bag on the ground, applied force cannot be positively transmitted through the drag rod 1 to the travel bag through the fixed mounting rod 2, and the travel bag may be forced to move out of course, or to fall to the ground.
SUMMARY OF THE INVENTION
The present invention has been accomplished to provide a travel bag pulling handle which eliminates the aforesaid problems. According to the present invention, the pulling handle is a retractable handle including two joined inner tubes moved in and out of two sleeves, wherein two angular position control devices are respectively mounted on the bottom ends of the two inner tubes, for permitting the inner tubes to be set between a vertical position and an oblique position when the inner tubes have been moved out of the sleeves.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic drawing showing a pulling handle installed in a wheeled travel bag and operated according to the prior art.
FIG. 1A is a perspective view in an enlarged scale of a part of the pulling handle shown in FIG. 1.
FIG. 1B is a sectional view in an enlarged scale of a part of the pulling handle shown in FIG. 1, showing the drag rod turned relative to the fixed mounting rod.
FIG. 2 shows a pulling handle installed in a travel bag according to the present invention.
FIG. 3 is an exploded view of the pulling handle according to the present invention.
FIG. 4A is a sectional view of the present invention, showing the inner tube moved to from the collapsed position to the extended position.
FIG. 4B is another sectional view of the present invention, showing the inner tube moved from the extended position to the collapsed position.
FIG. 5A is a schematic drawing showing the inner tube turned relative to the sleeve on the travel bag according to the present invention.
FIG. 5B is a sectional in an enlarged scale of a part of the present invention, showing the inner tube turned to the oblique position, the steel ball forced into engagement with the first rounded recess.
FIG. 5C is similar to FIG. 5B but showing the inner tube turned to the vertical position, the steel ball forced into engagement with the second rounded recess.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 2, a carrying handle in accordance with the present invention is generally comprised of two parallel sleeves 20 fixedly mounted in a travel bag 3, two mounting blocks 4 respectively mounted on the travel bag 3 to hold the top ends of the sleeves 20, and two inner tubes 10 joined by a hand grip and moved in and out of the sleeves 20.
Referring to FIG. 3, the sleeve 20 comprises a first locating hole 21 and a second locating hole 22 near its top and bottom ends. The inner tube 10 is a square tube having a pin hole 12 near its bottom end. A locating block 40 is coupled to the bottom end of the inner tube 10 by a coupling block 30. The coupling block 30 comprises a square top coupling tube 37 fitted into the bottom end of the inner tube 10 and fixedly secured to the pin hole 12 by a locating pin 11, a flat bottom coupling plate 31 pivoted to the locating block 40 and a flange 38 raised around the periphery on the middle stopped outside the sleeve 20. The flat bottom coupling plate 31 comprises a transverse pivot hole 32, a flat bottom edge 33, a bevel front edge 34 extended upwardly outwards from the flat bottom edge 33, a first rounded recess 35 at the bevel front edge 34, and a second rounded recess 36 at the flat bottom edge 33. The locating block 40 is a hollow block comprising two parallel upright plates 41 raised from its top side, the upright plates 41 having a respective pivot hole 42 respectively connected to the transverse pivot hole 32 of the flat bottom coupling plate 31 of the coupling block 30 at two opposite sides by a pivot 43, a transverse through hole 47 near its hollow bottom end, and a vertical screw hole 44 at its top side between the upright plates 41. A spring member 60 is mounted inside the locating block 40. A bit 61 is fixedly mounted on one end of the spring member 60, and pushed by the spring force of the spring member 60 out of the transverse through hole 47 of the locating block 40 into engagement with the first locating hole 21 or second locating hole 22 of the sleeve 20. An adjustment screw 52 is mounted inside the locating block 40 and threaded into the vertical screw hole 44 from the bottom side. A compression spring 51 is mounted in the vertical screw hole 44 and supported on the adjustment screw 52. A steel ball 50 is supported on the compression spring 51 and forced by it into engagement with the rounded recess 35 or 36 on the flat bottom coupling plate 31 of the coupling block 30.
Referring to FIGS. 4A and 4B, when the inner tube 10 is pulled upwards from the sleeve 20, the bit 61 is forced into the inside of the transverse through hole 47 on the locating block 40, for permitting the inner tube 10 to be pulled to the extended position outside the sleeve 20. When the inner tube 10 is pulled to the extended position, the transverse through hole 47 of the locating block 40 becomes in alignment with the first locating hole 21 on the sleeve 20, and the bit 61 is immediately forced by the spring force of the spring member 60 out of the transverse through hole 47 into engagement with the first locating hole 21, and therefore the inner tube 10 is retained in the extended position (see FIG. 4B). On the contrary, when the inner tube 10 is forced downwards, the bit 61 is forced into the inside of the transverse through hole 47 on the locating block 40, for permitting the inner tube 10 to be lowered from the extended position shown in FIG. 4B to the collapsed position shown in FIG. 4A. When the inner tube 10 is lowered to the collapsed position, the transverse through hole 47 of the locating block 40 becomes in alignment with the second locating hole 22 on the sleeve 20, and the bit 61 is immediately forced by the spring force of the spring member 60 out of the transverse through hole 47 into engagement with the second locating hole 22, and therefore the inner tube 10 is retained in the extended position (see FIG. 4A).
Referring to FIGS. 5A, 5B and 5C, when the inner tube 10 is moved to the extended position, it can be adjusted between a vertical position shown in FIG. 5C and an oblique position shown in FIG. 5B. When the inner tube 10 is moved to the extended position, the steel ball 50 is forced by the compression spring 51 into engagement with the second rounded recess 36 on the flat bottom edge 33 of the bottom coupling plate 31 of the coupling block 30, and therefore the inner tube 10 is retained in a vertical position in line with the sleeve 20 (see FIG. 5C). When the inner tube 10 is pulled downwards with force, the bottom coupling plate 31 of the coupling block 30 is turned with the inner tube 10 to force the second rounded recess 36 away from the steel ball 50, and to force the first rounded recess 35 into engagement with the steel ball 50, and therefore the inner tube 10 is retained in an oblique position relative to the sleeve 20 (see FIG. 5B). Further, by turning the adjustment screw 52 in the vertical screw hole 44, the spring power of the compression spring 51 is relatively adjusted.
While only one embodiment of the present invention has been shown and described it will be understood that various modifications and changes could be made thereunto without departing from the spirit and scope of the invention disclosed. | A travel bag pulling handle is provided having two angular position control devices respectively mounted on bottom ends of two inner tubes. The inner tubes can be set in a vertical position and an oblique position when the inner tubes have been retracted from respective sleeves inside the travel bag. | 0 |
This is a continuation of application Ser. No. 13/430,062, filed Mar. 26, 2012, now U.S. Pat. No. 8,455,195, which is a continuation of Ser. No. 11/826,141, filed Jul. 12, 2007, now U.S. Pat. No. 8,143,000, which is a continuation of Ser. No. 10/278,089, filed Oct. 23, 2002, now U.S. Pat. No. 7,258,975, which is a continuation of Ser. No. 09/485,415, filed Feb. 10, 2000, now U.S. Pat. No. 6,485,908, which is a 371 of PCT/EP98/05175, filed Aug. 14, 1998, which claims the benefit of priority to U.S. Provisional Application No. 60/055,863, filed Aug. 15, 1997, all of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention concerns a mutation responsible for autosomal prelingual non-syndromic deafness and a method for the detection of this hereditary sensory defect for homozygous and heterozygous individuals. The invention concerns more particularly a specific deletion of at least one nucleotide in the connexin 26 (Cx 26) gene and especially in a guanosine rich region, notably between the nucleotides 27 and 32. The invention is also directed to the use of polynucleotide, or fragments thereof, for example as tools useful for the in vitro detection of a mutation of a gene belonging to the Cx26 gene family.
Profound or severe prelingual deafness affects one child in a thousand in developed countries (Morton N E. Genetic epidemiology of hearing impairment. In Genetics of hearing impairment. (The New York Acad Sci, New York 1991; 630:16-31). It is a major handicap as it impedes language acquisition.
According to studies performed in a U.S. population of children with non-syndromic (isolated) prelingual deafness and in whom an obvious environmental cause has been excluded, it is estimated that up to two-thirds of the cases have a genetic basis (Marazita M L, Ploughman L M, Rawlings B, Remington E, Amos K S, Nance W E. Genetic epidemiological studies of early-onset deafness in the U.S. school-age population. Am J Med Genet 1993; 46:486-91). These forms are mainly sensorineural and are almost exclusively monogenic. The major mode of inheritance is autosomal recessive (DFNB), involving 72% to 85% of cases, this fraction increasing to 90% when only profound deafness is taken into account.
Autosomal recessive prelingual deafness is known to be genetically highly heterogeneous. Estimates of the number of DFNB loci vary from thirty to one hundred (Petit C. Autosomal recessive non-syndromal hearing loss. In Genetics and Hearing Impairment. Martini A, Read A P, Stephens D, eds (Whurr, London) 1996; 197-212), for a review), of which fourteen have so far been mapped to the human chromosomes (Petit C. Genes responsible for human hereditary deafness: symphony of a thousand. Nature Genet 1996; 14:385-91) for review, (Verhoeven K, Van Camp G, Govaerts P J, et al. A gene for autosomal dominant non-syndromic hearing loss (DFNA12) maps to chromosome 11q22-24. Am J Hum Genet 1997; 60:1168-74 and Campbell D A, McHale D P, Brown K A, et al. A new locus for non-syndromal autosomal recessive sensorineural hearing loss (DFNB16) maps to human chromosome 15q21-q22. J Med Genet 1997; in press).
A majority of the families attending genetic counseling clinics consist of normal hearing parents with a single deaf child who wish to know the risk of recurrence of the defect. In most cases, given the major role of environmental causes of prelingual deafness, it is not usually possible even to recognize whether the hearing loss is of genetic origin. Genetic counseling in such families would be greatly improved by an ability to detect DFNB mutations. In this respect, the high genetic heterogeneity of the condition represents a major obstacle.
After the initial identification of the DFNB1 locus on 13q11 in a large consanguineous Tunisian family (Guilford P, Ben Arab S, Blanchard S, et al. A non-syndromic form of neurosensory, recessive deafness maps to the pericentromeric region of chromosome 13q. Nature Genet 1994; 6:24-8), two studies performed on New Zealand/Australian families (Maw M A, Allen-Powell D R, Goodey R J, et al. The contribution of the DFNB1 locus to neurosensory deafness in a Caucasian population. Am J Hum Genet 1995; 57:629-35), and on Italian/Spanish families (Gasparini P, Estivill X, Volpini V, et al. Linkage of DFNB1 to non-syndromic neurosensory autosomal-recessive deafness in Mediterranean families. Eur J Hum Genet 1997; 5:83-8) suggested that this locus might be a major contributor to prelingual deafness in these populations, although individual lod scores obtained in these families were not significant owing to the small size of these families.
Recently, the Cx26 gene, which encodes a gap junction protein, connexin 26, has been shown to underlie DFNB1 deafness. Two different G→A substitutions resulting in premature stop codons in three DFNB1 linked consanguineous Pakistani families have been reported (Kelsell D P, Dunlop J, Stevens H P, et al. Connexin 26 mutations in hereditary non-syndromic sensorineural deafness. Nature 1997; 387:80-3). These two substitutions were identified, respectively, at codon 77 and at codon 24. This result has offered the opportunity directly to assess this hypothesis.
The difficulties encountered in genetic counseling for prelingual non-syndromic deafness due to the inability to distinguish genetic and non-genetic deafness in the families presenting a single deaf child was one of the reasons that led the inventors to undertake a characterization of the spectrum and prevalence of mutations present in the Cx26 gene in 35 families from several parts of the world with autosomal recessive prelingual deafness.
SUMMARY OF THE INVENTION
The determination of a mutation in the Cx26 gene has notably rendered possible the use of a detection probe as a tool for the identification of a specific form of autosomal prelingual non-syndromic deafness, and more particularly the useful role of a newly identified 30delG (a G deletion at position 30; position 1 being the first base of the initiator codon) mutation in such families. This invention establishes that the contribution of the DFNB1 locus predominantly results essentially from the 30delG mutation. It is now believed that the 30delG accounts for about three-quarters of all recessive DFNB1 mutations.
The invention is thus intended to provide a purified polynucleotide having a chain of nucleotides corresponding to a mutated sequence, which in a wild form encodes a polypeptide implicated in hereditary sensory defect. The mutated purified polynucleotide presents a mutation responsible for prelingual non-syndromic deafness.
The invention also provides oligonucleotides comprising of 15 to 50 consecutive nucleotides of the mutated purified polynucleotide that are useful as primers or as probes.
In addition, the invention aims to supply a method and a kit for the detection of the hereditary sensory defect for homozygous as heterozygous individuals.
According to the invention, the purified polynucleotide having a chain of nucleotides corresponding to a mutated sequence, which encodes in a wild form a polypeptide implicated in hereditary sensory defect, presents a mutation responsible for prelingual non-syndromic deafness selected from the group consisting of a specific deletion of at least one nucleotide.
By mutation, according to the invention it means a specific deletion of at least one nucleotide. Thus, a mutated sequence means a polynucleotide sequence comprising at least a mutation.
A chain of nucleotides, according to the invention, means a polynucleotide, which encodes not necessarily a polypeptide, but which presents between 27 and 2311 nucleotides linked together.
The invention particularly concerns a purified polynucleotide wherein, the specific mutation is a deletion located in a region encoding connexin 26 of chromosome 13q11-12, preferably located in a guanosine rich region starting at nucleotide 27 preferably at nucleotide 30, and extending to nucleotide 32 or nucleotide 35, all the recited nucleotides being inclusive. More particularly according to the invention, the specific deleted purified polynucleotide encodes for a truncated polypeptide.
By truncated polypeptide, according to the invention it means a fragment of the polypeptide, which does not present the properties of the wild form of the polypeptide either in length, in amino acid composition, or in functional properties.
A preferred embodiment of a specific deletion is a guanosine deletion at position 30, also called “30delG mutation”. Another preferred embodiment of the specific deletion is a 38 bp deletion beginning at position 30.
The invention also includes a purified polynucleotide, which hybridizes specifically with any one of the polynucleotides as defined above under the following stringent conditions: at low temperatures between 23° C. and 37° C., in the presence of 4×SSC buffer, 5×Denhardt's solution, 0.05% SDS, and 100 μg/ml of salmon sperm DNA. (1×SSC corresponds to 0.15 M NaCl and 0.05M sodium citrate; 1×Denhardt's solution corresponds to 0.02% Ficoll, 0.02% polyvinylpyrrolidone and 0.02% bovine serum albumin).
The invention also concerns an oligonucleotide useful as a primer or as a probe comprising 15 to 50 consecutive nucleotides of the polynucleotide according to any one of the polynucleotides as defined above. The oligonucleotide sequence is selected from the following group:
A first couple:
5′-TCTTTTCCAGAGCAAACCGCC-3′
(SEQ ID NO. 1)
5′-TGAGCACGGGTTGCCTCATC-3′.
(SEQ ID NO. 2)
The length of the PCR product has been obtained from 285 bp in length;
A second couple allowing to explore the other part of the reading frame:
5′-GACACGAAGATCAGCTGCAG-3′
(SEQ ID NO. 3)
5′-CCAGGCTGCAAGAACGTGTG-3′
(SEQ ID NO. 4)
A third couple:
5′-CTAGTGATTCCTGTGTTGTGTGC-3′;
(SEQ ID NO. 9)
and
5′ ATAATGCGAAAAATGAAGAGGA-3′
(SEQ ID NO. 10)
and
A fourth couple:
5′-CGCCCGCCGCGCCCCGCGCCCGGCCCGCC
(SEQ ID NO. 14)
GCCCCCGCCCCCTAGTGATTCCTGTGTTGTGT
GC-3′;
and
5′ ATAATGCGAAAAATGAAGAGGA-3′.
(SEQ ID NO. 10)
Another oligonucleotide useful as a probe is selected from the following group:
5′-AGACGATCCTGGGGGTGTGAACAAA-3′
(SEQ ID NO. 5)
5′-ATCCTGGGGGTGTGA-3′
(SEQ ID NO. 6)
5′-AGACGATCCTGGGGGCTCACCGTCCTC-3′.
(SEQ ID NO. 7)
In addition, the invention concerns a method for the detection of an hereditary sensory defect, namely autosomal prelingual non-syndromic deafness, for homozygous as heterozygous individuals in a biological sample containing DNA, comprising the steps of:
a) bringing the biological sample into contact with a oligonucleotide primers as defined above, the DNA contained in the sample having been optionally made available to hybridization and under conditions permitting a hybridization of the primers with the DNA contained in the biological sample;
b) amplifying the DNA;
c) revealing the amplification products;
d) detecting the mutation.
Step d) of the above-described method may comprise a Single-Strand Conformation Polymorphism (SSCP), a Denaturing Gradient Gel Electrophoresis (DGGE) sequencing (Smith, L. M., Sanders, J. Z., Kaiser, R. J., Fluorescence detection in automated DNA sequence analysis. Nature 1986; 321:674-9); a molecular hybridization capture probe or a temperature gradient gel electrophoresis (TGGE).
Step c) of the above-described method may comprise the detection of the amplified products with an oligonucleotide probe as defined above.
According to the invention, a biological sample can be a blood sample extracted from people suffering from any kind of deafness with any criteria as follows: neurosensorial or mixed isolated deafness, advanced or not, at any degree of severity, concerning familial or sporadic case, or individuals exposed to noise, or individuals suffering from a low acoustic, or individuals susceptible to carry an anomaly in the gene, or from an embryo for antenatal diagnostic.
Another aim of the invention comprises a method for the detection of an hereditary sensory defect, the autosomal prelingual non-syndromic deafness, for homozygous and heterozygous individuals in a biological sample containing DNA, comprising the steps of:
a) bringing the biological sample into contact with an oligonucleotide probe according to the invention, the DNA contained in the sample having been optionally made available to hybridization and under conditions permitting a hybridization of the primers with the DNA contained in the biological sample; and
b) detecting the hybrid formed between the oligonucleotide probe and the DNA contained in the biological sample.
Step b) of the above-described method may consist in a single-strand conformation. Polymorphism (SSCP), a denaturing gradient gel electrophoresis (DGGE) or amplification and sequencing.
The invention also includes a kit for the detection of an hereditary sensory defect, the autosomal prelingual non-syndromic deafness, for homozygous as heterozygous individuals, said kit comprising:
a) oligonucleotides according to the invention;
b) the reagents necessary for carrying out DNA amplification; and
c) a component that makes it possible to determine the length of the amplified fragments or to detect a mutation.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention will be more described in greater detail by reference to the drawings in which:
FIG. 1 depicts the results of temperature gradient gel electrophoresis for detection of mutants in which:
Lanes 1 and 2: DNA from normal patients. Lanes 3 and 4: DNA from homozygous patients with 30delG mutation. Lanes 5 and 6: DNA from heterozygous patients. Lane 7: PCR control without DNA. Lane 8: PCR fragment amplified from a normal DNA and hybridized with a standard DNA fragment harboring the 30delG mutation. Lane 9: PCR fragment amplified from a mutant homozygous DNA and hybridized with a normal standard DNA fragment harboring the guanine 30.
DETAILED DESCRIPTION OF THE INVENTION
Prelingual non-syndromic (isolated) deafness is the most frequent hereditary sensory defect in children. The inheritance in most is autosomal recessive. Several dozens of genes might be involved, only two of which, DFNB1 and DFNB2, have so far been identified (Kelsell, D. P., et al., Connexin 26 mutations in hereditary non-syndromic sensorineural deafness. Nature 1997; 387:80-3; Liu, X-Z, et al., Mutations in the myosin VIIA gene cause non-syndromic recessive deafness, Nature Genet 1997; 16:188-90; and Weil, D., et al., The autosomal recessive isolated deafness, DFNB2, and the Usher 1B syndrome are allelic defects of the myosin-VIIA. Nature Genet 1997; 16:191-3). A search was made searched for mutations in the gene encoding connexin 26, Cx26, which has recently been shown to be responsible for DFNB1. Mutation analysis of Cx26 was performed by PCR amplification on genomic DNA and sequencing of the single coding exon.
Example 1
Patients
Thirty-five affected families from various geographical regions, mainly France, New Zealand and Australia, Tunisia and Lebanon, were studied. They could be classified into three categories: (1) consanguineous families each having a significant linkage to the DFNB1 locus; (2) small non-consanguineous families in which linkage analysis was compatible with the involvement of DFNB1; and (3) small families in which no linkage analysis had been undertaken.
The first category consists of six large families living in geographically isolated regions. Five were from Tunisia, two from the north and three from the south. Linkage to the DFNB1 locus in the two families from northern Tunisia (families 20 and 60) had previously been reported (Guilford P, Ben Arab S, Blanchard S, et al., A non-syndromic form of neurosensory, recessive deafness maps to the pericentromeric region of chromosome 13q. Nature Genet 1994; 6:24-8); the three families from southern Tunisia (S15, S19 and ST) and the family from Lebanon (LH) comprise total of three, five, two, and five deaf children, respectively, the deafness being of severe or profound degree. The marriages were between first cousins (S15, ST and LH) and between first and second cousins (S19). Linkage analysis of these six families resulted in individual lod scores ranging from 2.5 to 10 with polymorphic markers from the DFNB1 region (D13S175, D13S141, D13S143 and D13S115).
The second category of patients comprises seven New Zealand families with at least two deaf siblings (families 51, 1160, 1548, 1608, 1773, 1873, 1877) and one Australian (9670) family. Family 1608 was atypical in that four siblings sharing the same DFNB1 marker haplotypes had a mild to moderate deafness (severe at high frequency), with the child of one of them being profoundly deaf. In family 1873, the unrelated parents (individuals II.2 and II.3) were deaf as well as their two children, and we have therefore considered this as two families, bringing to nine the total of independent families. Apart from families 1608 and 1873, no parent acknowledged any hearing impairment. These nine families showed cosegregation between deafness and polymorphic markers of the DFNB1 region with maximum individual lod scores ranging from 0.6 to 1.2. Ten other families in the original study of Maw et al. (Maw M A, Allen-Powell D R, Goodey R J, et al. The contribution of the DFNB1 locus to neurosensory deafness in a Caucasian population. Am J Hum Genet 1995; 57:629-35) had shown no cosegregation and one other cosegregating family was not tested for Cx26 mutations. The New Zealand families were all of Caucasian origin with no known Polynesian admixture. According to the antecedent family names, the ancestral proportion among the families reflected that of the general Caucasian New Zealand population with the great predominance being of Anglo-Celtic patrimony and a small fraction due to migration from continental Europe. Neither parental consanguinity, nor links between any of the families were recognized. In the Australian case, the father was from Northern Ireland and the mother from Yorkshire, England.
The third category is composed of nineteen families living in France and two in New Zealand, each with at least two children having a severe to profound deafness. No parent acknowledged any hearing impairment, except for the mother in family P16 and the father in family P17 who had moderate and progressive high-frequency hearing loss. Five of these families had foreign ancestors from Lebanon (family P3), Turkey (family P4), Portugal (family P9), Algeria (family P14) and Poland (father in family P16). In two of the families (P7 and P14), the parents were distantly related.
Example 2
Amplification of the coding exon of Cx26 PCRs were carried out on genomic DNA using a set of primers that allowed the amplification of the entire coding sequence of the Cx26 gene, which consists of a single coding exon (Kelsell D P, Dunlop J, Stevens H P, et al. Connexin 26 mutations in hereditary non-syndromic sensorineural deafness. Nature 1997; 387: 80-4 Primer sequences were as follows:
5′-TCTTTTCCAGAGCAAACCGCC-3′
(SEQ ID NO. 1)
and
5′-TGAGCACGGGTTGCCTCATC-3′.
(SEQ ID NO. 2)
PCR conditions were: 35 cycles of 95° C., 1 min; 58° C., 1 min; 72° C., 2 min. The PCR product obtained was 777 bp in length.
Example 3
DNA Sequencing
Sequencing of the PCR products was performed as previously described (Smith L. M. Sanders J Z, Kaiser R J, et al., Fluorescence detection in automated DNA sequence analysis, Nature 1986; 321:674-9) using the dideoxy chain terminator method on an Applied Biosystems DNA sequencer ABI373 with fluorescent dideoxynucleotides. The primers used were the same as those for the PCR amplification plus two internal primers:
5′-GACACGAAGATCAGCTGCAG-3′
(SEQ ID NO. 3)
and
5′-CCAGGCTGCAAGAACGTGTG-3′.
(SEQ ID NO. 4)
Example 4
Mutations in Consanguineous Tunisian and Lebanese DFNB1 Families
In these families the involvement of the DFNB1 locus could be demonstrated by linkage analysis. In four of the five families from Tunisia (S15, S19, 20, and 60) and in the Lebanese family (LH), the same mutation was detected in all affected children on both Cx26 alleles, namely, a deletion of a guanosine (G) in a sequence of six G extending from position 30 to 35 (position 1 being the first base of the initiator codon) (Table 1). This mutation is hereafter referred to as 30delG mutation according to the nomenclature proposed by Beaudet and Tsui ((Beaudet A L, Tsui L-C. A suggested nomenclature for designating mutations, Hum Mutation 1993; 2: 245-8)). It creates a frameshift, which results in a premature stop codon at nucleotide position 38. The mutation segregating in the fifth family from Tunisia (ST) was identified as a G to T transversion at nucleotide position G39 creating a premature stop codon (GAG→TAG) at codon 47, and was designated E47X. In each family, normal hearing parents were found to be heterozygous for the corresponding mutation.
Example 5
Mutations in Small Nonconsanguineous New Zealand and Australian Families Consistent with DFNB1 Linkage
In these families, segregation analysis has previously been reported as compatible with the involvement of the DFNB1 locus (Maw M A, Allen-Powell D R, Goodey R J, et al. The contribution of the DFNB1 locus to neurosensory deafness in a Caucasian population. Am J Hum Genet 1995; 57: 629-35). The deaf individuals from five of the nine families (51, 1160, 1608 (III.20), 1873 (II.3) and 1877) were homozygous for the 30delG mutation. The deaf children from family 1773 were heterozygous for 30delG. Deaf individual II.2 from family 1873 (see “subjects” and Table 1) was heterozygous for a deletion of 38 bp beginning at nucleotide position G30, designated 30del38. No other mutation was detected in the deaf children of family 1773 and the deaf individual (II.2) in family 1873. Nevertheless, in this last individual, a deletion of the polymorphic marker immediately proximal to the Cx26 gene (locus D13S175) had previously been observed (Maw M A, Allen-Powell D R, Goodey R J, et al. The contribution of the DFNB1 locus to neurosensory deafness in a Caucasian population. Am J Hum Genet 1995; 57: 629-35), which may indicate that a DNA rearrangement has impaired the functioning of the other Cx26 allele of the gene in cis. In family 9670, compound heterozygosity for a missense mutation (R184P) and an in frame single-codon deletion (delE138) was observed in affected siblings. In only one family (1548) was no Cx26 mutation detected. Results are summarized in Table 1.
Example 6
Mutations in Small Families Uncharacterized for DFNB1 Linkage Living in France and New Zealand
Nineteen families (P1 to 17, L14190 and L13131) living in France and two in New Zealand (families 1885 and 2254) were studied. In these families, cosegregation of the deafness with polymorphic markers had not been analysed. Deaf children from six of the twenty-one families (P1, P3, P5, P9, P10, and P16) were found to be homozygous for the mutation 30delG. In five additional families (P6, P11, P14, P17, and 1885), deaf children were heterozygous for this mutation; no other mutation was detected in these families. In the ten remaining families, no mutation in the Cx26 gene was found.
Example 7
Molecular Hybridization Using Allele-Specific Capture Probes
Molecular hybridization capture probe (see, e.g., D. Chevrier et al. PCR product quantification by non-radioactive hybridization procedures using an oligonucleotide covalently bound to microwells. Molecular and Cellular Probes 1993; 7: 187-197 and D Chevrier et al. Rapid detection of Salmonella subspecies I by PCR combined with non-radioactive hybridization using covalently immobilized oligonucleotide on a microplate. FEMS Immunology and Medical Microbiology 1995; 10: 245-252 each of which is incorporated by reference herein) permit specific detection of the 30delG mutation. The technique has been adapted to permit rapid diagnosis of prelingual non-syndromic deafness caused by the 30delG mutation. The technique provides certain advantages in a clinical setting because it uses stable, nonradioactive molecules, it can be easily automated, and it is well adapted to large scale analysis.
Using primers designed for PCR amplification, the region of interest in the Cx26 gene is amplified from genomic DNA samples. The primer sequences are as follows:
CONN3:
5′-CTAGTGATTCCTGTGTTGTGTGC-3′
(SEQ ID NO. 9)
CONN4:
5′ ATAATGCGAAAAATGAAGAGGA-3′
(SEQ ID NO. 10)
PCR is performed with the CONN3 (SEQ ID NO:9) and CONN4 (SEQ ID NO:10) primers (1 μM each), an aliquot of the DNA to be analyzed (2 μl, 100-300 ng), 1.5 mM MgCl 2 , 200 μM dNTP, and Taq polymerase. The amplification program consists of the following steps: 1) 95° C., 5 min; 2) addition of enzyme, 95° C., 1 min; 3) 60° C., 1 min (ramp rate=0.25° C./s); 4) 72° C., 1 min; 5) repeat steps 2 to 4 for 40 cycles; and 6) 72° C., 10 min. PCR products are verified by a rapid gel electrophoresis.
The amplified PCR product contains either the normal or the mutant Cx26 sequence. To distinguish between the normal and mutant sequence, two capture probes are designed. The sequences of these two capture probes are as follows:
For detection of normal sequence:
CONN6:
5′-AAAAAAAATCCTGGGGGGTGTG-3′
(SEQ ID NO. 11)
For detection of mutant sequence:
CONN7: 5′-AAAAAAAATCCTGGGGGTGTGA-3′ (SEQ ID NO. 12)
Each capture probe must be 22 nucleotides long. Furthermore, to be efficient, the capture probe must include an A 7 spacer at its 5′ end and a hybridization region of 15 bases. Such a capture probe is able to specifically differentiate the mutant sequence from the normal sequence. Thus, CONN6 (SEQ ID NO:11) is designed to specifically hybridize with the normal sequence, whereas CONN7 (SEQ ID NO:12) is designed to specifically hybridize with the mutant sequence.
Before attaching the capture probes to a microtiter plate, they are phosphorylated at their 5′ ends. The phosphorylation is carried out for 1 hour at 37° C. in presence of 20 nmoles of CONN6 (SEQ ID NO:11) or CONN7 (SEQ ID NO:12) oligonucleotides, 100 μM ATP, 10 units T4 polynucleotide kinase in 200 μl of buffer (50 mM Tris-HCl pH 7.4; 10 mM MgCl 2 5 mM dithiothreitol; and 1 mM spermidine). The mixture is heated for 10 min. at 68° C. to inactivate the T4 polynucleotide kinase, then the oligonucleotide is precipitated by adding 145 μl of 10 M CH 3 COONH 4 , 15 μl H 2 O, and 800 μl iced ethanol. After a 30 min. incubation in ice, the e mixture is centrifuged for 20 min. at 12,000×g at 4° C. The resulting pellet is washed with 500 μl iced ethanol (70%) and dissolved in 800 μl of TE buffer. The phosohorylated oligonucleotide concentration is determined by optical density at 260 nm.
Before attaching the phosphorylated oligonucleotides to microplates, they are denatured by heating at 95° C. for 10 min. and rapidly cooled in ice to avoid the formation of secondary structure. 500 ng of phosphorylated CONN6 (SEQ ID NO:11) or CONN7 (SEQ ID NO:12) and 1 μl of 1 M 1-methylimidazole, pH 7, is added to each well of a microplate, which is kept on ice. The total volume of each well is adjusted to 70 μl with distilled water, before adding 30 μl of a cold, 1-ethyl-3(3-dimethylaminopropyl) carbodiimide solution (167 mM). The microplate is covered and incubated for 5 hours at 50° C. in an incubator (Thermomix® from Labsysterns). After the 5-hour incubation, the microplate is washed three times with a warm solution (50° C.) of 0.4 N NaOH containing 0.25% SDS. The microplate is incubated for 5 min. with the same warm solution and washed again with warm NaOH/SDS (50° C.). Finally, the microplate is washed five times with TE buffer. The coated microplate can be kept several months at 4° C., if the wells are filled with TE buffer.
The amplified sequences from the genomic DNA samples are incubated with a biotinylated detection probe in the coated microplates. Unlike the capture probes; which are allele specific, the detection probe can hybridize with both the normal and mutant sequences. The sequence of the detection probe is:
CONN12: 5′-CAGCATTGGAAAGATCTGGCTCA-3′. (SEQ ID NO. 13)
The amplified sequences and the detection probe, which is biotinylated at its 5′ end, are denatured directly in the microplates by successively adding to each well: 95 μl of water, 5 μl of PCR reaction, 40 μl of biotinylated probe (SEQ ID NO:13) at 22 nM diluted in water, and 14 μl 1 N NaOH. After 10 min., 21 μl of 1 M NaH 2 PO 4 and 1% Sarkosyl is added to each well to bring the total volume to 175 μl per well. The final concentration of the detection probe is 5 nM. The microplate is covered and incubated overnight at 40° C. in an incubator (Thermomix® from Labsystems) and then extensively washed (5 times) with TBS-Tween to remove the excess biotinylated probe (SEQ ID NO:13).
An immunoenzymatic method is used to detect the hybridized probe. Each well receives 100 μl of the conjugate (Extravidine—alkaline phosphatase, Sigma E-2636) diluted 1/4000 in TBS-BSA-Tween. The microplate is covered and incubated for 1 hour at 25° C. Following the incubation, the microplate is washed 5 times with TBS-Tween. Then 200 μl of preheated (37° C.) substrate (7.5 mg para-nitro-phenyl-phosphate in 20 ml of the following buffer: 1 M diethanolamine pH 9.8 containing 1 mM MgCl 2 ) are added to each well. The microplate is covered and incubated for 3 hours at 37° C. The absorbance is measured at 405 nm to determine the specific signal and at 630 nm to determine the background noise.
The hybridization ratio (R) between the signal obtained with CONN6 (SEQ ID NO:11) probe (normal sequence) and that obtained with CONN7 (SEQ ID NO:12) probe mutant sequence) is calculated. The calculated R values are used to determine the genotypes of the sample DNA as follows: homozygous for the normal Cx26 sequence (R≧2), heterozygous for the 30delG mutation (0.5<R<2), and homozygous for the 30delG mutation (R≦0.5), The range of the hybridization ratio (R) can be slightly modified when the number of samples increases. The following table represents an example of results obtained with 39 samples.
Hybridization ratio (R)
Genotype:
Normal
Homozygous 30delG
Heterozygous
5.96
0.48
1.33
5.43
0.17
1.13
3.39
0.21
0.73
4.14
0.16
0.63
4.09
0.28
1.4
2.76
0.13
0.73
2.2
0.21
0.76
3.97
0.4
0.73
4.07
1.06
3
2.76
3.66
3.87
3.92
3.26
5.17
2.74
4.51
6.3
3.49
4.05
3.17
Number
22
8
9
Mean value
3.91
0.26
0.94
Standard
1.06
0.12
0.29
deviation
Range
(6.3-2.2)
(0.48-0.13)
(1.4-0.63)
Example 8
Temperature Gradient Gel Electrophoresis
Temperature gradient gel electrophoresis (TGGE) permits the detection of any type of mutation, including deletions, insertions, and substitutions, which is within a desired region of a gene. (See, e.g. D. Reiner et al. Temperature-gradient gel electrophoresis of nucleic acids: Analysis of conformational transitions, sequence variations and protein-nucleic acid interactions. Electrophoresis 1989; 10: 377-389; E. P. Lessa and G. Applebaum Screening techniques for detecting allelic variation in DNA sequences. Molecular Ecology 1993; 2: 119-129 and A. L. Börresen-Dale et al. Temporal Temperature Gradient Gel Electrophoresis on the D Code™ System. Bio-Rad US/EG Bulletin 2133; the entire disclosure of each publication is incorporated by reference herein.) However, TGGE does not permit one to determine precisely the type of mutation and its location.
As in the previously described molecular hybridization technique, the region of interest in the Cx26 gene is first amplified from genomic DNA samples by PCR. The primer sequences are as follows:
CONN2: 5′-CGCCCGCCGCGCCCCGCGCCCGGCCCGCC (SEQ ID NO. 14) GCCCCCGCCCCCTAGTGATTCCTGTGTTGTGT GC-3′ CONN4: 5′ ATAATGCGAAAAATGAAGAGGA-3′ (SEQ ID NO. 10)
PCR is performed with 1 μM of the CONN2 (SEQ ID NO:14) primer, which has a GC clamp at its 5′ end, and 1 μM of the CONN4 (SEQ ID NO:10) primer, an aliquot of the DNA to be analyzed (2 μl, 100-300 ng), 1.5 mM MgCl 2 , 200 μM dNTP, and Taq polymerase. The amplification program consists of the following steps: 1) 95° C., 5 min; 2) addition of enzyme, 95° C., 1 min; 3) 60° C., 1 min (ramp rate=0.25° C./s); 4) 72° C., 1 min; 5) repeat steps 2 to 4 for 40 cycles; and 6) 72° C., 10 min.
Analyzing these PCR amplification fragments by TGGE can differentiate between homozygous (normal or mutant) samples, which produce a single band on a gel, and heterozygous samples, which produce three bands. However, differentiating between genomic samples that are homozygous for the normal sequence and genomic samples that are homozygous for the 30delG mutants requires an additional step.
To differentiate normal homozygous versus mutant homozygous samples, an aliquot of the amplified PCR product is mixed with either a known, normal homozygous sample or a known, 30delG mutant homozygous sample and analyzed for heteroduplex formation. If the amplified PCR product derives from a normal, homozygous sample, it will form a heteroduplex with the known, 30delG mutant homozygous sample. On the other hand, if the amplified PCR product derives from a mutant, homozygous sample, it will form a heteroduplex with the known, normal homozygous sample. To promote heteroduplex formation in these mixtures, they are denatured at 95° C. for 5 min, followed by a renaturation step at 60° C. for 45 min.
The PCR fragments from the initial amplification and those that are subjected to the additional heating steps to permit heteroduplex formation are analyzed on a 10% polyacrylamide gel containing 7 M urea. By way of example, a 30 ml gel is prepared by combining the following ingredients:
12.6 g urea 0.75 ml 50×TAE 7.5 ml acrylamide:bisacrylamide (37.5:1) at 40% water to bring volume to 30 ml 30 μl Temed (added extemporaneously) 300 μl 10% ammonium persulfate (added extemporaneously).
After adding the Temed and ammonium persulfate, the gel is poured between two glass plates (Dcode Universal Mutation Detection System® from BIORAD) and allowed to polymerize for 1 hour.
An aliquot (7.5 μl) of the PCR mixture is mixed with 7.5 μl of 2× sample solution (2 mM EDTA pH 8; 70% glycerol; 0.05% xylene cyanol; 0.05% bromophenol blue), and introduced into a gel well. Electrophoresis is performed for 4-5 hours at 150V in 1.25×TAE buffer with a temperature gradient ranging from 61° C. to 62° C. at a rate of 0.2° C. per hour. Following electrophoresis, the gel is incubated for 6 min. in 1.25×TAE containing 25 μg/ml ethidium bromide. Excess ethidium bromide is removed by a 20 min. wash in 1.25×TAE, and the DNA fragments are visualized with a UV transilluminator.
A typical TGGE result is represented in FIG. 1 . The amplified DNA from homozygous patients (normal or mutant) produces only one band. The amplified DNA from heterozygous patients results in three different fragments in the polyacrylamide gel. The more intense band, which migrates more rapidly, corresponds to both homoduplexes, which cannot be separated in this gel. The other two bands, which migrate more slowly, correspond to both kinds of heteroduplexes.
The DNA of normal homozygous patients can be differentiated from the DNA of mutant homozygous patients by analyzing the PCR fragments that were subjected to the conditions that permitted heteroduplex formation. Heteroduplexes form when the PCR amplified fragment from a normal homozygous genome is mixed with sequences from a known, mutant homozygous genome, or when the PCR amplified fragment from a mutant homozygous genome is mixed with sequences from a known, normal homozygous genome. These heteroduplexes are visible by TGGE analysis. Consequently, the DNA of normal and mutant homozygous patients can be easily differentiated by this technique using the primers described in the present study.
In all the known DFNB1 families (6/6), in all but one (8/9) of the putatively DFNB1-linked families, and in about half (11/21) of the families not tested for DFNB1 linkage, a mutation in Cx26 was detected. Furthermore, of the 44 chromosomes reckoned to be independent upon which a Cx26 mutant allele was identified or inferred, 33 (75%) were found to carry the same deletion of a guanosine, G, at position 30 (30delG).
Cx26 mutations represent a major cause of recessively inherited prelingual deafness and would be implicated in about half of cases in the examined populations. In addition, one specific mutation, 30delG, accounts for the majority (about three-quarters in our series) of the Cx26 mutant alleles.
The wild type connexin 26 gene published in LEE S. W. et al. (1992) J. Cell Biol. 118: 1213-1221 has the following sequence:
(SEQ ID NO: 15)
1
GATTTAATCC TATGACAAAC TAAGTTGGTT CTGTCTTCAC CTGTTTTGGT
51
GAGGTTGTGT AAGAGTTGGT GTTTGCTCAG GAAGAGATTT AAGCATGCTT
101
GCTTACCCAG ACTCAGAGAA GTCTCCCTGT TCTGTCCTAG CTATGTTCGT
151
GTGTTGTGTG CATTCGTCTT TTCCAGAGCA AACCGCCCAG AGTAGAAG AT
201
G GATTGGGGC ACGCTGCAGA CGATCCTGGG GGGTGTGAAC AAACACTCCA
251
CCAGCATTGG AAAGATCTGG CTCACCGTCC TCTTCATTTT TCGCATTATG
301
ATCCTCGTTG TGGCTGCAAA GGAGGTGTGG GGAGATGAGC AGGCCGACTT
351
TGTCTGCAAC ACGCTGCAGC CAGGCTGCAA GAACGTGTGC TACGATCACT
401
ACTTCCCCAT CTCCCACATC CGGCTATGGG CCCTGCAGCT GATCTTCGTG
451
TCCAGCCCAG CGCTCCTAGT GGCCATGCAC GTGGCCTACC GGAGACATGA
501
GAAGAAGAGG AAGTTCATCA AGGGGGAGAT AAAGAGTGAA TTTAAGGACA
551
TCGAGGAGAT CAAAACCCAC AAGGTCCGCA TCGAAGGCTC CCTGTGGTGG
601
ACGTACACAA GCAGaATCTT CTTCCGGGTC ATCTTCGAAG CCGCCTTCAT
651
GTACGTCTTC TATGTCATGT ACGACGGCTT CTCCATGCAG CGGCTGGTGA
701
AGTGCAACGC CTGGCCTTGT CCCAACACTG TGGACTGCTT TGTGTCCOGG
751
CCCACGGAGA AGACTGTCTT TCACAGTGTT CATGATTGCA GTGTCTGGAA
801
TTTGCATCCT GCTGAATGTC ACTGAATTGT GTTATTTGCT AATTAGATAT
851
TGTTCTGGGA AGTCAAAAAA GCCAGTTTAA CGCATTGCCC AGTTGTTAGA
901
TTAAGAAATA GACAGCATGA GAGGGATGAG GCAACCCGTG CTCAGCTGTC
951
AAGGCTCAGT CGCCAGCATT TCCCAACACA AAGATTCTGA CCTTAAATGC
1001
AACCATTTGA AACCCCTGTA GGCCTCAGGT GAAACTCCAG ATGCCACAAT
1051
GAGCTCTGCT CCOCTAAACC CTCAAAACAA AGGCCTAATT CTATGCCTGT
1101
CTTAATTTTC TTTCACTTAA GTTAGTTCCA CTGAGACCCC AGGCTGTTAG
1151
GGGTTATTGG TGTAAGGTAC TTTCATATTT TAAACAGAGG ATATCGGCAT
1201
TTGTTTCTTT CTCTGAGGAC AAGAGAAAAA AGCCAGGTTC CACAGAGGAC
1251
ACAGAGAAGG TTTGGGTGTC CTCCTGGGGT TCTTTTTGCC AACTTTCCCC
1301
ACGTTAAAGG TGAACATTGG TTCTTTCATT TGCTTTGGAA GTTTTAATCT
1351
CTAACAGTGG ACAAAGTTAC CAGTGCCTTA AACTCTGTTA CACTTTTTGG
1401
AAGTGAAAAC TTTGTAGTAT GATAGGTTAT TTTGATGTAA AGATGTTCTG
1451
GATACCATTA TATGTTCCCC CTGTTTCAGA GGCTCAGATT GTAATATGTA
1501
AATGGTATGT CATTCGCTAC TATGATTTAA TTTGAAATAT GGTCTTTTGG
1551
TTATGAATAC TTTGCAGCAC AGCTGAGAGA GGCTGTCTGT TGTATTCATT
1601
GTGGTCATAG CACCTAACAA CATTGTAGCC TCAATCGAGT GAGACAGACT
1651
AGAAGTTCCT AGTTGCCTTA TGATAGCAAA TGGCCTCATG TCAAATATTA
1701
GATGTAATTT TGTGTAAGAA ATACAGACTG GATGTACCAC CAACTACTAC
1751
CTGTAATGAC AGGCCTGTCC AACACATCTC CCTTTTCCAT GCTGTGGTAG
1801
CCAGCATCGG AAAGAACGCT GATTTAAAGA GGTGAGCTTG GGAATTTTAT
1851
TGACACAGTA CCATTTAATG GGGAGACAAA AATGGGGGCC AGGGGAGGGA
1901
GAAGTTTCTG TCGTTAAAAA CGAGTTTGGA AAGACTGGAC TCTAAATTCT
1951
GTTGATTAAA GATGAGCTTT GTOTACCTTC AAAAGTTTGT TTGGCTTACC
2001
CCOTTCAGCC TCCAATTTTT TAAGTGAAAA TATAACTAAT AACATGTGAA
2051
AAGAATAGTA GCTAAGGTTT AGATAAATAT TGAGCAGATC TATAGGAAGA
2101
TTGAACCTGA ATATTGCCAT TATGCTTGAC ATGGTTTCCA AAAAATGGTA
2151
CTCCACATAG TTCAGTGAGG GTAAGTATTT TCCTGTTGTC AAGAATAGCA
2201
TTGTAAAAGC ATTTTGTAAT AATAAAGAAT AGCTTTAATG ATATGCTTGT
2251
AACTAAAATA ATTTTGTAAT GTATCAAATA CATTTAAAAC ATTAAAATAT
2301
AATCTCTATA AT
The wild type connexin 26 gene is published in D. T. Kiang et al. (1997) Gene 199 (1-2): 165-171171; has the following sequence:
1
GATTTAATCC TATGACAAAC TAAGTTGGTT CTGTCTTCAC CTGTTTTGGT
51
GAGGTTGTGT AAGAGTTGGT GTTTGCTCAG GAAGAGATTT AAGCATGCTT
101
GCTTACCCAG ACTCAGAGAA GTCTCCCTGT TCTGTCCTAG CTAGTGATTC
151
CTGTGTTGTG TGCATTCGTC TTTTCCAGAG CAAACCGCCC AGAGTAGAAG
201
ATGGATTGGG GCACGCTGCA GACGATCCTG GGGGGTGTGA ACAAACACTC
251
CACCAGCATT GGAAAGATCT GGCTCACCGT CCTCTTCATT TTTCGCATTA
301
TGATCCTCGT TGTGGCTGCA AAGGAGGTGT GGGGAGATGA GCAGGCCGAC
351
TTTGTCTGCA ACACCCTGCA GCCAGGCTGC AAGAACGTGT GCTACGATCA
401
CTACTTCCCC ATCTCCCACA TCCGGCTATG GGCCCTGCAG CTGATCTTCG
451
TGTCCACGCC AGCGCTCCTA GTGGCCATGC ACGTGGCCTA CCGGAGACAT
501
GAGAAGAAGA GGAAGTTCAT CAAGGGGGAG ATAAAGAGTG AATTTAAGGA
551
CATCGAGGAG ATCAAAACCC AGAAGGTCCG CATCGAAGGC TCCCTGTGGT
601
GGACCTACAC AAGCAGCATC TTCTTCCGGG TCATCTTCGA AGCCGCCTTC
651
ATGTACGTCT TCTATGTCAT GTACGACGGC TTCTCCATGC AGCGGCTGGT
701
GAAGTGCAAC GCCTGGCCTT GTCCCAACAC TGTGGACTGC TTTGTGTCCC
751
GGCCCACGGA GAAGACTGTC TTTCACAGTG TTCATGATTC CAGTGTCTGG
801
AATTTGCATC CTGCTGAATG TCACTGAATT GTGTTATTTG CTAATTAGAT
851
ATTGTTCTGG GAAGTCAAAA AAGCCAGTTT AACGCATTGC CCAGTTGTTA
901
GATTAAGAAA TAGACAGCAT GAGAGGGATG AGGCAACCCG TGCTCAGCTG
951
TCAAGGCTCA GTCGCCAGCA TTTCCCAACA CAAAGATTCT GACCTTAAAT
1001
GCAACCATTT GAAACCCCTG TAGGCCTCAG GTGAAACTCC AGATGCCACA
1051
ATGAGCTCTG CTCCCCTAAA GCCTCAAAAC AAAGGCCTAA TTCTATGCCT
1101
GTCTTAATTT TCTTTCACTT AAGTTAGTTC CACTGAGACC CCAGGCTGTT
1151
AGGGGTTATT GGTGTAAGGT ACTTTCATAT TTTAAACAGA GGATATCGGC
1201
ATTTGTTTCT TTCTCTGAGG ACAAGAGAAA AAAGCCAGGT TCCACAGAGG
1251
ACACAGAGAA GGTTTGGGTG TCCTCCTGGG GTTCTTTTTG CCAACTTTCC
1301
CCACGTTAAA GGTGAACATT GGTTCTTTCA TTTGCTTTGG AAGTTTTAAT
1351
CTCTAACAGT GGACAAAGTT ACCAGTGCCT TAAACTCTGT TACACTTTTT
1401
GGAAGTGAAA ACTTTGTAGT ATGATAGGTT ATTTTGATGT AAAGATGTTC
1451
TGGATACCAT TATATGTTCC CCCTGTTTCA GAGGCTCAGA TTGTAATATG
1501
TAAATGGTAT GTCATTCGCT ACTATGATTT AATTTGAAAT ATGGTCTTTT
1551
GGTTATGAAT ACTTTGCAGC ACAGCTGAGA GAGGCTGTCT GTTGTATTCA
1601
TTGTGGTCAT AGCACCTAAC AACATTGTAG CCTCAATCGA GTGAGACAGA
1651
CTAGAAGTTC CTAGTTGGCT TATGATAGCA AATGGCCTCA TGTCAAATAT
1701
TAGATGTAAT TTTGTGTAAG AAATACAGAC TGGATGTACC ACCAACTACT
1751
ACCTGTAATG ACAGGCCTGT CCAACACATC TCCCTTTTCC ATGCTGTGGT
1801
AGCCAGCATC GGAAAGAACG CTGATTTAAA GAGGTGAGCT TGGGAATTTT
1851
ATTGACACAG TACCATTTAA TGGGGAGACA AAAATGGGGG CCAGGGGAGG
1901
GAGAAGTTTC TGTCGTTAAA AACGAGTTTG GAAAGACTGG ACTCTAAATT
1951
CTGTTGATTA AAGATGAGCT TTGTCTACCT TCAAAAGTTT GTTTGGCTTA
2001
CCCCCTTCAG CCTCCAATTT TTTAAGTGAA AATATAACTA ATAACATGTG
2051
AAAAGAATAG AAGCTAAGGT TTAGATAAAT ATTGAGCAGA TCTATAGGAA
2101
GATTGAACCT GAATATTGCC ATTATGCTTG ACATGGTTTC CAAAAAATGG
2151
TACTCCACAT ACTTCAGTGA GGGTAAGTAT TTTCCTGTTG TCAAGAATAG
2201
CATTGTAAAA GCATTTTGTA ATAATAAAGA ATAGCTTTAA TGATATGCTT
2251
GTAACTAAAA TAATTTTGTA ATGTATCAAA TACATTTAAA ACATTAAAAT
2301
ATAATCTCTA TAAT
(SEQ ID No. 8). The ATG underlined in the sequences corresponds to the start codon. The guanine residue “G”, which is in bold print, marks the end of the guanosine rich region between nucleotides 27 and 32, inclusive.
TABLE I
Mutations in the Cx26 coding exon in individuals affected
with familial forms of prelingual deafness
Family (geographical
30delG
Other
origin)
mutation
mutation
Deafness
DFNB1-linked families
S15 (sTu)
homozygous
—
profound
S19 (sTu)
homozygous
—
profound
ST (sTu)
—
homozygous
profound
E47X
20 (nTu)
homozygous
—
profound
60 (nTu)
homozygous
—
profound
LH (Leb)
homozygous
—
severe-profound
Families consistent
with DFNB1 linkage
51 (NZ)
homozygous
—
severe-profound
1160 (NZ)
homozygous
—
moderate-severe*
1548 (NZ)
—
—
profound
1608 (NZ)
homozygous
—
profound**
1773 (NZ)
heterozygous
—
profound
1873 individual II.3 (NZ)
homozygous
—
moderate
1873 individual II.2 (NZ)
—
heterozygous
profound
30del38
1877 (NZ)
homozygous
—
profound
9670 (Aust)
delE118/R14
moderate-severe
8P
Families uncharacterized
for DFNB1 linkage
P1 (Fr)
homozygous
—
severe-profound
P2 (Fr)
—
—
profound
P3 (Leb)
homozygous
—
severe-profound
P4 (Tur)
—
—
severe-profound
P5 (Fr)
homozygous
—
profound
P6 (Fr)
heterozygous
—
severe-profound
P7 (Fr)
—
—
moderate
P8 (Fr)
—
—
moderate
L13131 (Fr)
—
—
profound
L14190 (Fr)
—
—
mild-moderate
P9 (Por)
homozygous
—
severe-profound
P10 (Fr)
homozygous
—
severe-profound
P11 (Fr)
heterozygous
—
moderate-severe
P12 (Fr)
—
—
severe-profound
P13 (Fr)
—
—
profound
P14 (Alg)
heterozygous
—
moderate-severe
P15
—
—
severe-profound
P16 (Fr)
homozygous
—
severe**
(mother/Fr,
father/Pol)
P17 (Fr)
heterozygous
—
severe***
1885 (NZ)
heterozygous
—
profound
2254 (NZ)
—
—
moderate-severe
The analysis reported here concerns deaf children of the various families except for family 1873 (see patients and methods).
* moderate in one ear, severe in the other ear.
** moderate hearing loss in mother (severe at high frequencies), *** mild hearing loss in father, who are heterozygous carriers for the 30delG mutation.
Geographical origins: (Alg) Algeria, (Aust) Australia, (Fr) France, (Leb) Lebanon, (NZ) New Zealand, (Pol) Poland, (Por) Portugal, (nTu) North Tunisia, (sTu) South Tunisia, (Tur) Turkey | A purified polynucleotide having a chain of nucleotides corresponding to a mutated sequence, which in a wild form encodes a polypeptide implicated in hereditary sensory defect, wherein said mutated purified polynucleotide presents a mutation responsible for prelingual non-syndromic deafness selected from the group consisting of a specific deletion of at least one nucleotide. | 2 |
CROSS REFERENCE TO RELATED APPLICATION
The present application is a divisional of copending application Ser. No. 09/450,331 filed on Nov. 29, 1999.
BACKGROUND OF THE INVENTION
This invention relates to a frequency-voltage conversion circuit and a receiving apparatus applicable for a direct conversion receiver which receives and demodulates a FSK Frequency Shift Keying) signal.
A superheterodyne method and a direct conversion method are generally used in a FSK (Frequency Shift Keying) receiver. In each method, demodulation is carried out by the use of the known F-V (Frequency-Voltage) conversion.
Referring to FIG. 1, description will be made about a related direct conversion receiver using the F-V conversion.
In a Weber receiver illustrated in FIG. 1 the direct conversion receiver, a base-band cross signal is brought up to intermediate frequency (namely, up-conversion is conducted), and the F-V conversion is performed.
The FSK signal sent from a receiver (not shown) is received by an antenna 101 , is amplified by a high frequency amplifier 102 , and is given to mixers 103 and 104 , respectively.
A local oscillator 107 produces an oscillation signal. The oscillation signal is shifted with π/2 by the use of a π/2 shifter 105 , and is given to the mixer 103 . Further, the frequency signal from the local oscillator 107 is directly given to the mixer 104 .
Low pass filters (hereinafter, abbreviated as LPFs) 106 and 108 are connected to the mixers 103 and 104 , respectively. In this condition, output signals from the mixers 103 and 104 are given to the LPSs 106 and 108 , respectively.
Each of the LPFs 106 and 108 has passing band equivalent to the base band signal, and realizes or obtains selectivity between adjacent channels. Further, the LPFs 106 and 108 supply output signals corresponding to signals from the mixers 103 and 104 into an up-conversion portion 130 .
In this case, the up-conversion portion 130 is composed of mixers 109 and 110 , a local oscillator 113 , a π/2 shifter, and an adder 112 , as illustrated in FIG. 1 .
With this structure, the mixer 109 is given with an oscillation signal from the local oscillator 113 . Further, the oscillation signal from the local oscillator 113 is shifted with π/2 by a π/2 shifter 111 , and is given to the mixer 110 .
Signals multiplied by the mixers 109 and 110 are added by the adder 112 Alternatively, the multiplied signals may be subtracted by a subtracter (not shown). An output signal of the adder 112 is converted by the use of a delay detection portion 114 .
In the above-mentioned Weber receiver 131 , a carrier wave frequency of the received FSK signal is defined as ω/2 π while frequency deviation is defined as ±Δω/2 π. In this condition, the received FSK signal Sr FSK is represented by the following equation.
Sr FSK =cos(ω±Δω) t
In this event, when the output signal S OSC1 of the local oscillator 107 is defined as S OSC1 =sin ωt, the output signals S MIX3 and S MIX4 of the mixers 103 and 104 are represented by the following equations, respectively.
S MIX3 =cos(ω±Δω) t ·cos ω t = ½{cos(ω±Δω+ω) t +cos(ω±Δω·ω) t}= ½{cos(2ω±Δω) t +cos(±Δω t )}
S MIX4 =cos(ω±Δω) t ·sin ω t = ½{sin(ω±Δω+ω) t +sin(ω±Δω·ω) t}= ½{sin(2ω±Δω) t +sin(±Δω t )}
First terms of these equations are removed by the LPFs 106 and 108 . Therefore, the outputs S LPF6 and S LPF8 of the LPFs 106 and 108 are represented by the following equations.
S LPF6 =½{cos(Δω t )} (1)
S LPF8 =±½{sin(Δω t )} (2)
In this case, when calculation is carried out without limiter amplifiers 128 and 129 so as to be readily understood, an output signal Vout of the up-conversion portion 130 is modified as follows. Herein, it is to be noted that the output signal of the local oscillator 113 is defined by S OSC2 =sin ω2t.
Vout= ½{cos(Δω t )sin ω2 t )}±½{sin(Δω t )cos ω2 t )}=½{sin(ω2±Δω)} (3)
From the above-mentioned result, the base band signal I, Q is converted to a signal having frequency deviation of ±Δω/2πwhen the intermediate frequency ω2/2π is defined as a center.
Subsequently, when the limiter amplifiers 128 and 129 are inserted between the LPF 106 and the mixer 109 or between the LPF 108 and the mixer 110 , the condition is explained as follows.
When inputs into the mixers 109 and 110 becomes rectangular wave by the limiter amplifiers 128 and 129 , outputs S LPF6′ and S LPF8′ , are modified as follows by Fourier transforming the above-mentioned equations (1) and (2) Herein, it is to be noted that constant is defined as k=2/π.
S LPF6′ =k {cos(Δω t )}+⅓·cos(3 Δωt ) +⅕·cos(5 Δωt )+. . .} (1′)
S LPF8′ =k {sin(ω2±ω) t + ⅓·sin(3(ω2±Δω) t + ⅕·sin(5(ω2±Δω) t )+. . .} (2′)
Namely, the output Vout′ of the up-conversion portion 130 is similarly considered to be the modification of the above-mentioned equation (3). Thereby, the following equation is introduced.
Vout= k {sin(ω2±ω) t + ⅓·sin(3(ω2±Δω) t + ⅕·sin(5(ω2±Δω) t )+. . .} (3′)
Consequently, it is found out that the conversion-up becomes possible even when the limiter amplifiers 128 and 129 are inserted between the LPF 106 and the mixer 109 or between the LPF 108 and the mixer 110 .
Although the Weber receiver 131 has been suggested as a SSB (Single Side Band) receiver, it is found out that the Weber receiver 131 is applicable as the FSK receiver, as explained above.
The output signal of the adder 112 is given to the delay detection portion 114 , and the F-V conversion is carried out in the delay detection portion 114 .
In FIG. 2, a detail structure of the delay detection portion 114 is illustrated. Further, a timing chart showing change (waveform) of each signal of each portion in the delay detection portion 114 is illustrated in FIG. 3 .
A signal V A from the adder 112 is converted into output signals V B and V C by removing amplitude demodulation components by the use of a limiter amplifier 119 .
Subsequently, the output signals V B and V C are converted into signals V D and V E having desired slopes at rising through common-emitter transistors 121 and 221 . Further, the signals V D and V E are converted into signals V F and V G by comparators 123 and 223 given with threshold level V TH26 from a reference voltage 126 .
In this event, the transistors 121 and 221 are coupled to constant current sources 120 , 220 and capacitors 122 , 222 , respectively.
Moreover, the signals V F and V G are converted into a signal V H via an AND gate (namely logical product). Thereby, pulse signal line, which has constant amplitude and constant delay time τ, is formed, as illustrated in FIG. 3 .
Finally, the pulse signal line V H is integrated by a LPF 125 , and converted into a voltage value V I corresponding to frequency. Further, the obtained voltage V I is converted into a logic data signal consisting of “1” and “0” by a converter (not shown).
In FIG. 4, frequency spectrums are illustrated so as to explain the above-mentioned structure. In an intermediate stage in the FIG. 4, center frequency between frequency of “1” and frequency of “0” becomes carrier wave frequency.
In FIG. 5, characteristic obtained the delay detection portion 114 is illustrated. In the above-mentioned example, demodulation sensitivity KD is defined as KD=2τ V [V/Hz]. Consequently, the characteristic is affected by variation of τ and V. Herein, it is to be noted that τ represents delay time while V indicates output amplitude of the signal V H .
Moreover, the delay time τ is inversely proportional to variation of the constant current sources 120 and 220 illustrated in FIG. 2, and is proportional to variation of static capacitance of the capacitors 122 and 222 . Further, the delay time τ is proportional to the threshold voltage V TH26 .
Specifically, the demodulation sensitivity is fluctuated by variation of manufacturing condition. In addition, Further, F-V conversion output amplitude is varied in the direct-conversion method using the F-V conversion. As a result, receiving condition may be deteriorated.
Further, the power supply voltage is restricted from the same reason, and reneality of the F-V conversion is degraded. In consequence, receiving condition is also degraded.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a frequency-voltage conversion circuit which is capable of correcting manufacturing variation and change with time caused by the variation.
It is another object of this invention to provide a frequency-voltage conversion circuit which is capable of demodulating a FSK signal with stable and high sensibility and linearity.
In a frequency-voltage conversion circuit according to this invention, integrating means gives a predetermined slope for rising or falling of a rectangular pulse signal.
First comparing means compares an output value of the integrating means with a threshold value, and produces a pulse signal line having a pulse width corresponding to frequency of the rectangular pulse signal.
Storing means stores and retains the threshold value. Smoothing means smooths the pulse signal line, and produces a voltage value corresponding to the frequency of the rectangular pulse signal.
Second comparing means compares the voltage value with a reference voltage, and charges and discharges electric charge for the storing means on the basis of the comparison result.
In this case, the integrating means comprises a constant current device which produces constant current, and a static capacitance device which stores the current.
With such a structure, the second comparing means discharges the electric charge from the storing means when the voltage value is higher than the reference voltage.
On the other hand, the second comparing means charges electric charge for the storing means when the voltage value is lower than the reference voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a related direct conversion receiver using F-V conversion;
Fig. 2 is a connection diagram showing a detail structure of the delay detection portion 114 illustrated in FIG. 1;
FIG. 3 is a timing chart showing change (waveform) of each signal of each portion in the delay detection portion 114 illustrated in FIG. 1;
FIG. 4 is diagram showing frequency spectrums for explaining function of the direct-conversion receiver;
FIG. 5 is a characteristic diagram showing characteristic obtained by the delay detection portion 114 illustrated in FIG. 1;
FIG. 6 is a block diagram showing a structure of a receiver according to a first embodiment of this invention;
FIG. 7 is a connection diagram showing a detail structure of the delay detection portion 14 illustrated in FIG. 6;
FIG. 8 is a timing chart showing change (waveform) of each signal of each portion in the delay detection portion 14 illustrated in FIG. 6;
FIG. 9 is a characteristic diagram showing difference of F-V conversion characteristic (demodulation sensitivity) due to difference of threshold level V TH16 ;
FIG. 10 is a connection diagram showing a detail structure of a delay detection portion 14 in frequency-voltage conversion circuit according to a second embodiment of this invention; and
FIG. 11 is a timing chart showing change (waveform) of each signal of each portion in the delay detection portion illustrated in FIG. 10 .
DESCRIPTION OF PREFERRED EMBODIMENTS
Hereinafter, description will be made about embodiments of this invention with drawings.
First Embodiment
Referring to FIG. 6, description will be made about a first embodiment of this invention.
A FSK (Frequency Shift Keying) signal transmitted from a transmitter (not shown) is received via an antenna 1 , is amplified by a high-frequency amplifier 2 ,and is given to mixers 3 and 4 , respectively.
An oscillation signal from a local oscillator 7 is shifted with 2/π by a 2/π shifter 5 . The shifted signal is given to the mixer 3 while the oscillation signal from the local oscillator 7 is directly given to the mixer 4 .
The mixers 3 and 4 are connected to LPFs (Low Pass Filters) 6 and 8 as channel filters, respectively. Output signals of the mixers 3 and 4 are given to the LPFs 6 and 8 .
Each of the LPFs 6 and 8 has passing band equivalent to a base band signal, and realizes or obtains selectivity between adjacent channels. Further, the LPFs 6 and 8 supply output signals corresponding to signals from the mixers 3 and 4 into an up-conversion portion 30 .
The up-conversion portion 30 is composed of a mixer 9 , a mixer 10 , a local oscillator 13 , a 2/π shifter 11 , and an adder 12 . The mixer 9 is given with an oscillation signal from the local oscillator 13 . On the other hand, the oscillation signal from the local oscillator 13 is shifted with 2/π by the 2/π shifter 5 . The shifted signal is given to the mixer 10 .
Signals multiplied by the mixers 9 and 10 are added by the use of an adder 12 . Alternatively, the multiplied signals may be subtracted by a subtracter (not shown).
The reference numeral 32 represents a switch which switches a signal obtained by a Weber receiver 31 with an output signal of the local oscillator 13 . The reference numeral 14 indicates a delay detection portion which F-V converts an output signal of the switch 32 . Further, the reference numeral 18 represents a control portion which controls the switch 32 and the delay detection portion 14 .
The switch 32 gives the output signal of the local oscillator 13 into the delay detection portion 14 when a control signal S 18 is put into “H” (high level). On the other hand, the switch 32 gives the output signal of the adder 12 into the delay detection portion 14 when the control signal S 18 is put into “L” (low level).
In FIG. 7, a signal V A (rectangular pulse signal) from the above adder 12 is removed amplitude modulation components thereof by a limiter amplifier 19 , and is converted into output signals V B and V C respectively.
Subsequently, the output signals V B and V C are converted into signals V D and V E having desired slopes at rising through common-emitter transistors 21 a and 21 b . Herein, it is to be noted that each of the signals V D and V E may have the slope at falling.
Further, the signals V D and V E are converted into signals V F and V G by comparators 23 a and 23 b.
In this event, the transistors 21 a and 21 b are coupled to constant current sources 20 a , 20 b and capacitors 22 a , 22 b , respectively. The comparators 23 a and 23 b are coupled to a capacitor 16 , and is given with an output signal of a VI amplifier 15 .
Further, the signals V F and V G are converted into a signal V H via an AND gate (logical product). Thereby, a pulse signal line V H , which has constant amplitude and constant delay time τ, is formed, as illustrated in FIG. 8 .
The pulse signal line V H is integrated by a LPF 25 , and is converted into a voltage value V I corresponding to frequency.
Further, the voltage value V I is compared with a reference voltage 17 (V REF ). An output signal of the V I amplifier 15 is supplied as a reference voltage of the comparator 23 a , 23 b.
With such a structure, when the control signal S 18 is put into “L” (low level), the switch 32 selects the output of the adder 32 . Consequently, the VI amplifier 15 is put into an off-state (namely, an output terminal is opened). Consequently, electric charge (threshold level V TH16 ) of the capacitor 16 is retained or kept.
On the other hand, when the control signal S 18 is put into “H” (high level), the switch 32 selects the output signal of the local oscillator 32 . As a result, the VI amplifier 15 is put into an on-state. Thereby, feedback in the delay detection portion 14 is activated.
As mentioned above, the signal V A from the delay detection portion 14 is removed the amplitude modulation components thereof by the limiter amplifier 19 , and is converted into the signals V B and V C . In this event, the signals V B and V C have phases reverse to each other.
Subsequently, the output signals V B and V C are converted into signals V D and V E by the common-emitter transistors 21 a and 21 b , and further, converted into signals V F and V G by the comparators 23 a and 23 b . Herein, it is to be noted that each of the comparators 23 a and 23 b has the threshold level V TH16 .
Further, the signals V F and V G are converted into a signal V H by via the AND gate. Thereby, pulse signal line V H having the constant amplitude and the constant delay time τ is formed, as described before.
Finally, the pulse signal line V H is integrated by the LPF 25 , and is converted into the voltage value V I corresponding to the frequency of the signal V A .
The voltage value V I is compared with the reference voltage V REF . As a result of the comparison, when the voltage value V I is higher than the reference voltage V REF , the output of the VI amplifier 15 is put into “L”. Thereby, electric charge off the capacitor 16 is discharged. In consequence, the threshold level V TH16 is lowered or reduced.
On the other hand, when the voltage value V I is lower than the reference voltage V REF , the output of the VI amplifier 15 is put into “H”. Thereby, electric charge of the capacitor 16 is charged. Thereby, the threshold level V TH16 is increased.
In the first embodiment, the delay time τ is adjusted on the condition that the control signal S 18 is put into “H”. Thereby, the voltage value V I from the delay detection portion 14 is converged to the reference voltage V REF . In this event, frequency given to the delay detection portion 14 is equal to center frequency of a second FSK signal.
On the other hand, when the control signal S 18 is put into “L”, a normal receiving state appears. In this case, frequency given to the delay detection portion 14 is equal to the second FSK signal. Therefore, the control signal S 18 is put into “H” during signal receiving wait state or during signal receiving state unnecessary to receive a signal.
The above-mentioned delay time τ is inversely proportional to current variation of the constant current source 20 a , 20 b . Further, the delay time τ is proportional to variation of static capacitance of the capacitor 22 a , 22 b , and is proportional to the threshold voltage V TH16 as the reference voltage given to the comparator 23 a , 23 b.
In this embodiment, when the voltage value V I is higher than the reference voltage V REF , the delay time τ becomes higher than a value to be essential. In this case, the VI amplifier 15 discharges electric charge of the capacitor 16 so as to reduce V TH16 . Thereby, the delay time τ becomes low. In consequence, the voltage value V I is reduced, and the voltage value V I is finally is converged to V REF .
On the other hand, when the voltage value V I is lower than the reference voltage V REF , the delay time τ becomes lower than the value to be essential. In this event, the VI amplifier 15 charges electric charge of the capacitor 16 so as to increase V TH16 . Thereby, the delay time τ becomes high. Consequently, the voltage value V I is increased, and the voltage value V I is finally is converged to V REF .
In FIG. 9, F-V conversion characteristic (demodulation sensibility) is illustrated in accordance with difference of the threshold levels V TH16 .
Herein, it is to be noted that each straight line A, B and C in FIG. 9 corresponds to each level A, B and C illustrated in FIG. 8 .
The voltage value V I is equal to a voltage corresponding to center frequency of the second FSK signal. Therefore, the voltage corresponding to the center frequency is compatible with the reference voltage V REF . Thereby, variation of the demodulation sensibility is substantially eliminated, and the F-V conversion characteristic is corrected as the straight line B illustrated in FIG. 9 .
When the receiving sate becomes normal by putting the control signal S 18 into “L”, the reference voltage V REF is used as reference voltage of a comparator or an A/D (Analog/Digital) converter given with the voltage VI, and thereby, corresponds to center frequency of accurate second FSK signal.
Second Embodiment
Referring to FIG. 10, description will be made about a second embodiment of this invention. Herein, it is to be noted that the same reference numeral is attached to the same portion as each portion illustrated in FIG. 7 .
In the second embodiment, a current control portion 27 is controlled by the use of a control signal S 18 from the control portion 18 . The current control portion 27 compares the voltage value V I with the reference voltage V REF , and controls constant current sources 40 a and 40 b on the basis of the comparing result via the feedback.
With such a structure, when the control signal S 18 is put into “L” (low level), current value of the constant current source 40 a , 40 b is kept to a constant value. On the other hand, when the control signal S 18 is put into “HH” (high level), the output of the local oscillator 13 selected by the switch 32 is given thereto. Thereby, the current control portion 27 is put into an on-state. Consequently, the feedback becomes active.
In this event, a signal V A is removed amplitude modulation components thereof by the limiter amplifier 19 , and is converted into signals V B and V C . The signals V B and V C are given with desired slopes corresponding to current values determined by constant current sources 40 a and 40 b , and are converted into signals V D and V E .
Further, the signals V D and V E are converted into signals V F and V G by comparators 23 a and 23 b . In this event, each of the comparators are given with threshold level V TH26 .
Further, logic product (negative logic product) is carried out for the signals V F and V G through an AND gate 24 . Thereby, pulse signal line V H is generated, as illustrated in FIG. 11 .
In the pulse signal line V H , amplitude and delay time τ are constantly kept. This signal line V H is integrated by a LPF 25 , and is converted into voltage value V I corresponding to the frequency of the signal V A .
In this case, the voltage value V I is compared with the reference voltage V REF . As the result of the comparison, when the voltage value V I is higher than the reference voltage V REF , the current control portion 27 controls so as to increase current value of the constant current source 40 a , 40 b.
On the other hand, when the voltage value V I is lower that the reference voltage V REF , the current control portion 27 controls so as to reduce the current value of the constant current source 40 a , 40 b.
More specifically, when the control signal S 18 is put into “H” (namely, the feedback is in an active state), the delay time τ is adjusted. Further, the F-V converted voltage value V I is converged into the reference voltage V REF . On the other hand, when the control signal S 18 is put into “L”, normal receiving state appears.
Therefore, the control signal S 18 is put into “H” so as to perform the feedback during signal receiving wait state or during signal receiving state unnecessary to receive a signal.
The delay time τ is inversely proportional to variation of the current value of the constant current source 40 a , 40 b , and is proportional to static capacitance of the capacitor 22 a , 22 b . Further, the delay time τ is proportional to the threshold level V TH26 given to the comparator 23 a , 23 b.
In this embodiment, when the voltage value V I is higher than the reference voltage V ERF , the delay time τ is becomes larger than a value to be essential. In such a case, the current control portion 27 controls so as to increase the current value of the constant current source 40 a , 40 b . Thereby, the voltage value V I becomes low, and the voltage value V I finally converges into V REF .
On the other hand, when the voltage value V I is lower than the reference voltage V ERF , the delay time τ is becomes lower than the value to be essential. In this case, the current control portion 27 controls so as to reduce the current value of the constant current source 40 a , 40 b . Thereby, the voltage value V I becomes large, and the voltage value V I finally converges into V REF .
Herein, it is to be noted that the voltage value V I is a voltage which corresponds to center frequency of the second FSK signal. Therefore, the voltage corresponding to the center frequency is made to be compatible with the referential voltage V REF . Thereby, variation of demodulation sensibility is substantially eliminated. Further, the F-V conversion characteristic is corrected as the straight line B illustrated in FIG. 9 .
When the control signal S 18 is put into “L” and is in the normal receiving state, the reference voltage V REF is used as the reference voltage of a comparator or a A/D converter which is supplied with the voltage value V I , and thereby, accurately corresponds to the center frequency of the second FSK signal. | In a frequency-voltage conversion circuit, integrating means gives a predetermined slope for rising or falling of a rectangular pulse signal. First comparing means compares an output value of the integrating means with a threshold value, and produces a pulse signal line having a pulse width corresponding to frequency of the rectangular pulse signal. Storing means stores and retains the threshold value. Smoothing means smooths the pulse signal line, and produces a voltage value corresponding to the frequency of the rectangular pulse signal. Second comparing means compares the voltage value with a reference voltage, and charges and discharges electric charge for the storing means on the basis of the comparison result. | 7 |
This is a continuation of application Ser. No. 08/507,618 filed Jul. 26, 1995, now abandoned.
FIELD OF THE INVENTION
The present invention relates generally to the field of magnetic recording and playback of digital information from a storage medium. More particularly, the present invention relates to a method for forming an array of magnetic read/write head elements from a unitary core bar, and a resultant head assembly structure.
BACKGROUND OF THE INVENTION
More and more critical information is being committed to computers, causing storage capacity to increase at a startling rate. The expansion of data storage requirements has fueled a need for better, more cost-effective tape backup solutions that feature high capacity, high performance and exceptional data integrity.
In the past, helical scan tape technology provided an acceptable solution for mid-range and low-end tape backup systems. Growing demands of contemporary data-intensive applications are quickly outpacing helical scan tape drive capabilities. One technology offering capacity, transfer rate and storage capacity gains over helical scan tape drives, is digital longitudinal streaming tape drives.
Longitudinal tape drives run the tape past a plurality of stationary heads at e.g. 100 to 150 inches per second during read/write data transfer operations, and faster during block searching. These drives place data in plural longitudinal tracks in comparison with slanted stripes of helical scan technology. Since the tracks are arranged longitudinally along the tape, additional recording tracks and channels enable parallel read/write data transfer operations, thereby increasing data transfer rates.
A longitudinal linear tape drive head assembly includes a pair of longitudinal channels. Within each channel, a read or verify head is spanned on each side by a write head, so that data may be read immediately after being written in order to verify the integrity of the data transfer operation, irrespective of direction of tape travel relative to the head. Typically the three heads of each channel are arranged in transverse alignment relative to a longitudinal axis of the tape within a head structure in contact with the tape as it streams past in one direction or the other during operation. One example of a prior head structure for use with digital longitudinal magnetic tape is provided by the present inventor's commonly assigned U.S. Pat. No. 5,055,959 entitled: "Tape Head with Low Spacing Loss Produced by Narrow and Wide Wear Regions", by commonly assigned U.S. patent application Ser. No. 08/094,413 filed on Jul. 19, 1993, for "Magnetic Tape Head", and by commonly assigned U.S. patent application Ser. No. 08/305,117, filed on Sep. 13, 1994, for "Magnetic Tape Head with Self-Regulating Wear Regions", the disclosures thereof being incorporated herein by reference thereto.
Conventional digital longitudinal tape head structures have heretofore typically included a number of discrete read/write core elements. Each core element must be located normally at a very precise location within the head structure in order to achieve desired multi-channel high track density recording within each tape and from tape to tape as tapes are exchanged on the tape drive mechanism. One significant drawback with conventional longitudinal tape heads is that the discrete read/write core elements were separately machined and assembled in place in precise alignment For example, the Quantum DLT6000 linear digital tape head structure requires some 48 miniature spacers and 12 individual cores, along with a multiplicity of islands and shields. All of these discrete elements had to be aligned precisely in place prior to various attachment/bonding procedures in assembly of the head structure, leading to high component and assembly costs.
Another prior approach has been to fabricate tape head elements in a row by using thin film techniques to deposit inductive write elements and magnetoresistive read elements. In this approach plural thin film write/read elements are deposited by thin film techniques upon a suitable wafer substrate. Each of the layers forming the elements is deposited under tight positional tolerances with respect to channel or track spacing, thereby eliminating need for subsequent aligning. The wafer is further processed and sliced into bars, with each bar containing a number of prearranged thin film write/read elements. However, the wafer process typically does not make efficient use of the surface area of the wafer and therefore minimizes the number of heads that may be fabricated upon a single wafer in a very capital intensive, expensive manufacturing process. Thus, while the thin film deposition method has eliminated some of the alignment issues during head assembly, its limited production yields and high capital manufacturing costs have restricted the use of this advanced magnetic recording technology to very high priced tape drive systems, such as the IBM 3480/90 streaming tape systems.
Thus, a hitherto unsolved need has remained for a low cost precision multiple head and manufacturing process for digital longitudinal tape recording systems.
SUMMARY OF THE INVENTION WITH OBJECTS
One object of the present invention is to form precision-aligned multiple read or write elements from a single bar of magnetic core material in a manner overcoming limitations and drawbacks of the prior art.
Another object of the present invention is to provide a ganged head formation method for a multiple channel linear tape recording and playback system in a manner realizing self alignment, efficient use of materials and low manufacturing and prime costs.
A further object of the present invention is to provide a multiple head assembly formed out of an integral bar of magnetic core material in a manner providing prearranged track spacing and alignment of the individual head elements.
One more object of the present invention is to provide a plural read/write element assembly having a unitary core structure in a manner minimizing magnetic cross-coupling between individual head elements of the assembly.
Yet another object of the present invention is to provide a multiple channel head assembly for a longitudinal tape storage system which employs conventional materials and manufacturing processes in order to realize a head assembly having inherently aligned read/write head elements at relatively low finished-product and manufacturing costs, with higher yields than hitherto obtained with more expensive thin film head technologies.
In accordance with one aspect of the present invention, a magnetic recording head assembly comprises a core-bar of ferromagnetic core material having a longitudinal axis; the core-bar defining a plurality of spaced-apart magnetic transducer elements, each element including:
a first pole segment defining a pole tip,
a second pole segment having a pole tip oppositely facing the pole tip of the first pole segment and separated by a narrow magnetic gap,
the magnetic gap between the pole tips being substantially aligned with the longitudinal axis of the core-bar and being filled with an insulative material, and
a coil of wire wound around at least one of the first and second pole segments,
the assembly further including structure defining longitudinal wear regions extending between the plurality of spaced-apart magnetic transducer elements.
In a further aspect of the present invention, a method of fabricating a magnetic recording head assembly comprising a plurality of precisely aligned, spaced apart magnetic transducer elements, comprises the steps of:
forming two elongated core-bars of ferromagnetic material so that each defines a longitudinal channel and so that the resultantly formed two core-bars have facing longitudinal edges aligned,
forming a plurality of aligned magnetic gap regions along one pair of oppositely facing edges of the formed elongated core-bars thereby rendering adjacent portions of the core bars as magnetic pole tips of the plurality of magnetic transducer elements,
joining the two formed elongated core-bars together into an elongate box structure by a non-ferromagnetic joinery medium along the aligned longitudinal edges including placement of non-ferromagnetic joinery medium within each one of the magnetic gap regions,
selectively removing portions of the elongate box structure to define at least one active pole segment extending to an included magnetic pole tip, and
winding a coil of wire around each said active pole segment.
These and other objects, advantages, aspects and features of the present invention will be more fully understood and appreciated upon consideration of the following detailed description of a preferred embodiment, presented in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the Drawings:
FIG. 1 is an isometric view of a first preferred embodiment of a multiple channel tape head assembly in accordance with principles of the present invention.
FIG. 2A is an isometric view of a shaped, generally box-shaped composite bar of ferromagnetic core stock defining an interior longitudinal pentagonal channel and other features ultimately resulting in the FIG. 1 embodiment.
FIG. 2B is an enlarged plan view of a head element region of the FIG. 2 core stock.
FIG. 3 is an isometric view of a multiple channel tape head core after completion of machining of the FIG. 2A core stock.
FIG. 4 is an isometric view of a tape face-plate for enclosing the FIG. 3 tape head core as shown in the FIG. 1 completed tape head assembly.
FIG. 5 is an isometric view of a second preferred embodiment of a multiple channel tape head assembly in accordance with principles of the present invention.
FIG. 6 is an isometric view of a shaped, generally box-shaped composite bar of ferromagnetic core stock defining an interior longitudinal pentagonal channel and other features ultimately resulting in the FIG. 5 embodiment.
FIG. 7 is an isometric view of the FIG. 6 composite bar following initial precision machining operations.
FIG. 8 is an isometric view of the FIG. 6 composite bar following further machining operations forming individual head elements.
FIG. 9A is an isometric view of the FIG. 6 composite bar following completion of machining operations, but before the individual coils are wound onto the active poles of the head elements.
FIG. 9B is an enlarged isometric plan view of one of the multiple tape heads of the FIG. 6 composite bar following completion of machining and glass emplacement steps at the FIG. 9A state of completion in the manufacturing process.
FIG. 10 is an isometric view of a third preferred embodiment of a multiple channel tape head assembly in accordance with principles of the present invention.
FIG. 11 is an isometric view of a shaped, generally box-shaped composite bar of ferromagnetic core stock defining an interior longitudinal pentagonal channel and other features ultimately resulting in the FIG. 10 embodiment.
FIG. 12 is an isometric view of the FIG. 10 composite bar following initial precision machining operations.
FIG. 13 is an isometric view of the FIG. 10 composite bar following further machining operations forming the individual head elements.
FIG. 14A is an isometric view of the FIG. 10 composite bar following completion of machining operations, but before the individual coils are wound onto the active poles of the head elements.
FIG. 14B is an enlarged isometric plan view of one of the multiple tape heads of the FIG. 10 composite bar following emplacement of glass at the FIG. 14 state of completion in the manufacturing process.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As illustrated in FIG. 1, a first preferred embodiment of a multiple channel tape head assembly 10 includes a shaped and processed integral core bar 12 of a suitable ferromagnetic ceramic core material, and a face-plate 14 of non-ferromagnetic material such as calcium titanate ceramic which shaped to mate with four read or write transducer elements 16, 18, 20, and 22. The elements 16, 18, 20 and 22 are formed as integral extensions of the bar 12 and extend outwardly from a back wall 23 of the bar 12.
Each magnetic head element 16-22 includes two integral pole pieces: an active pole piece 24 and a passive pole piece 26. A magnetic gap 28 is defined in each element 16-22 at an apex of the assembly as shown in the FIG. 1 orientation. Four coils of wire 36, 38, 40 and 42 are wound around each of the active pole pieces 24 of the four transducer elements 16, 18, 20 and 22, respectively.
The face-plate 14 includes four slots 30 (best seen in FIG. 4) which are aligned with the four transducer elements 16-22, so that after the head assembly 10 is assembled as shown in FIG. 1, the face-plate 14 encloses and supports the four integral plateau formations comprising the four write elements 16-22. As is conventional with magnetic tape heads, the outer surfaces of transducer elements 16-22 and a longitudinally aligned portion 32 of the face-plate 14 follow a predetermined radius of curvature.
FIG. 2A illustrates initial fabrication of the core bar 12. Two rectangular bars 12A and 12B of suitable ferromagnetic core material, such as a ferrite ceramic, are ground into a three-sided C shape, in which one side is at an acute angle relative to the other two sides which are normal to each other. The bars 12A and 12B, which may be ground or machined as segments of a single bar stock, are positioned as shown in FIG. 2A, and bonded together by conventional glass bonding 13 in grooves along commonly facing upper and lower edges. Alternatively, one of the bars, such as the bar 12A may have a generally C-shaped cross section, whereas the other bar 12B may have a generally I-shaped cross section, with a resultant asymmetrical core cross section in accordance with the teachings of commonly assigned U.S. Pat. No. 5,214,553, the disclosure thereof being incorporated herein by reference.
As shown in FIG. 2A and in greater detail in FIG. 2B, before the segments 12A and 12B are glass-bonded together, the segments 12A and 12B are carefully shaped into adjacently facing, contoured pole ends 34 at the locations of the head elements 16-22, thereby defining the very narrow magnetic gap 28 separating the pole pieces 24 and 26. When the segments 12A and 12B are bonded together by glass bonding, glass 13 fills the gaps 28 and the surrounding widened areas shown in FIG. 2B. The length of the gap 28 defines the longitudinal track width, and so the gap length is made very narrow, preferably on the order of one to two mils, or less.
FIG. 3 illustrates the core bar 12 after further processing. In the FIG. 3 view, the core material of the bar segments 12A and 12B has been removed by grinding, leaving behind four thin plateaus defining the elements 16, 18, 20 and 22. Each element 16-22 has a longitudinal dimension on the order of about 10-20 mils. The grinding operation is carried out e.g. by use of precision gang saws and grinders of the type used to separate slider wafers into slider bars in thin film head manufacturing technology, for example. The precision machining is employed to establish precise dimensions between the head elements 16-22, thus a distance d1 separates head 16 from head 18, whereas a distance d2 separates head 18 from head 20, and a distance d3 separates head 20 from head 22, and a distance d4 separates head 22 from a fiducial reference plane rp at one end of the composite bar 12. Also, as shown in FIG. 3, a transverse gap tolerance dimension t among all of the elements 16, 18, 20, and 22 is readily maintained by virtue of the fabrication of the elements 16-22 from a single composite core bar 12, as described.
Opposite end portions 15 and 17 of the composite bar 12 are machined to provide support walls having aligned top surfaces 19 for registering and supporting the face-plate 134 after its assembly onto the composite, shaped slider bar 12. The face-plate 14 may be secured to the bar 12 by a suitable adhesive material, such as a curable epoxy resin polymer. This step serves to reinforce the thin, very delicate plateaus forming the individual cores of the integral elements 16-22 and reduce the possibility of unwanted breakage of any of the elements incident to handling during further steps of the manufacturing process.
After the face-plate 14 is secured onto the bar 12, the coils 36, 38, 40 and 42 are wound around the active pole pieces 24 of each element, also as shown in FIG. 1. After the coils 36-42 are wound, the assembly 10 is ready for encapsulation within a larger head structure, along with other, head assemblies 10 in an aligned array thereof. Encapsulation and final machining of a tape face of the head structure will leave the magnetic gap regions 28 and the curved region 32 of the face-plate 14 exposed to the tape, while other adjacent portions of the assembly 10 will become embedded in a suitable encapsulating material. Before encapsulation, connector wires are connected to each of the thin wires of the coils 36-42 to enable reliable electrical connections to be made between each element 16-22 and a corresponding external read or write channel of the tape system.
Each coil 36-42 defines a magnetic circuit extending through the pole piece 24, the back wall 13 and the pole piece 26 at the vicinity of each element 16-22, respectively. The circuit is broken at the gap 28. Therefore, during a data writing operation, a magnetic flux will be generated when current is passed through a particular coil and pass through the magnetic circuit to the gap 28 adjacent the pole tips 34. At the same time, magnetic dipoles in a track of a magnetic tape (not shown) which is passing in contact over a completed head structure will become tangentially aligned with the flux in its direction of travel across the magnetic gap 28. Conversely, during a data reading operation, passage of a data tape having a magnetization pattern across the magnetic gap of an element 16-22 will result in a current being induced in accordance with magnetic dipole orientations on the tape.
Even though a single composite core bar 12 has been used to provide the four head elements 16, 18, 20, and 22, it has been discovered that when the distances d1, d2, and d3 are sufficiently long, very little, if any, cross-talk occurs between adjacent head elements. The stray flux magnetic circuit paths between adjacent heads are too long for the heads to cross-talk by mutual coupling. Preferably, the composite core bar 12 is comprised of single crystal ferrite ceramic material. Each of the coils 36-42 is a winding having e.g. 30 turns of fine gauge wire.
FIGS. 5-9B illustrate a second preferred embodiment of the present invention. In FIGS. 5-9B the same reference numerals are given to the same structural elements found in the head assembly 10 of FIGS. 1-4, and descriptions for those elements are not repeated. As shown in FIG. 6, a composite bar 12' is formed as two generally C-shaped sections 12A and 12B by longitudinal glass groove bonding techniques. However, before the glass bonding step, the narrowed head gap regions 28 are defined as shown in FIG. 2B. As noted above, the bar 12' can be formed of asymmetrical sections. In FIG. 7, the composite bar 12' is notched to form angled faces 102 and 104 on opposite sides of a longitudinal glass bond line 13. The faces 102 and 104 define widened wear regions 106 at the sites of the four head elements 16, 18, 20 and 22 and end regions 108 at respective ends of the composite bar 12'.
In a further forming step shown in FIG. 8, most of the material comprising the section 12A of the ferrite bar 12' is removed, leaving behind the active pole pieces 24 of each head element 16-22. In this example given in FIG. 8, some of the material of the segment 12B is also removed adjacent the lower longitudinal glass bond groove. The material removal step shown in FIG. 8 leaves bridging segments 102A of the segment 12A between the regions 106 and end regions 108. The widened wear regions are then grooved as at 110 in FIG. 9A and filled with glass 13 as shown in the enlarged detail view of FIG. 9A, in accordance with the teachings of U.S. Pat. No. 5,055,959 referred to above, leaving the pole ends and magnetic groove 28 intact. In the example of FIG. 9B, the width w of gap 28 may be approximately 8 mils. Returning to FIG. 5, the wire coils are wound around the respective active poles 24 of the heads 16, 18, 20 and 22, and the tape-facing surface of the composite bar 12' is ground to follow a predetermined radius of curvature denoted by the arc lines rc in FIG. 5. Thus, this second preferred embodiment avoids the use of the face-plate 14 described in conjunction with the first preferred embodiment 10.
A third preferred embodiment 200 of the present invention is depicted in FIGS. 10-14B. In this third embodiment the composite core bar 12, shown in FIG. 11 is prepared as with the previously described examples 10 and 100. In a second machining step, shown in FIG. 12, the faces 102 and 104 are defined as per the second example 100. Subsequent machining steps, shown in FIGS. 13 and 14A are different from those shown in FIGS. 8 and 9. In FIG. 13, the bar 12' is machined to have a form 12" in which considerably larger segments 102B are left in place to provide greater structural integrity for the resultant assembly 200. Otherwise the assembly 200 is very similar to the assembly 100 described above and illustrated in FIG. 5. As shown in FIG. 14B, each head is formed as a double-concave structure which is wide, e.g. 12 mils, at the periphery pw, and narrow, e.g. 1.0 mils, at the magnetic gap 28. The arcuate patterns forming the head are preferably formed by laser ablation of the ferrite bar material.
It should be noted that heads 16, 18, 20 and 22 which are used for writing are provided with a wider gap width w (e.g. about 8 mils), than heads used for reading (e.g. gap width is about 1-2 mils). Also, the ferrite bar stock 12 is initially about 50 mils wide along its upper face. A nominal distance between the heads 16 and 18, and between heads 20 and 22 is about 54 mils, whereas a nominal distance between heads 18 and 20 is about 156 mils, in the present examples.
Having thus described preferred embodiments of the invention, it will now be appreciated that the objects of the invention have been fully achieved, and it will be understood by those skilled in the art that many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosure and the description herein are purely illustrative and are not intended to be in any sense limiting. | A multiple channel magnetic tape head assembly defines a plurality of spaced-apart transducer elements along an integral bar of ferromagnetic material. Each element, formed by grinding operations performed upon the integral bar, has a magnetic gap and flux circuit which is isolated from cross-talking with the other elements. Each element is precisely located by the integral bar, portions of which remain after grinding. The head assembly provides an aligned longitudinal tape wear region and may further provide widened transverse wear regions adjacent to each of the transducer elements. A fabrication method for forming a multiple channel magnetic tape head assembly is also described. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to injecting one or more phases of steam into one or more formations from a single string of tubing by utilizing an impingement means in a side pocket mandrel or other downhole tools and including, if desired, an agitation device to control the quality and flow of steam. The invention may also include a centralizer to guide a tool string and disperse the steam.
2. Description of Related Art
In the past, various configurations of devices were used to inject steam and other fluids and gases into one or more zones of a formation to enhance hydrocarbon recovery, such as oil, from the earth. Depending on the medium injected and the properties of the formation, some of these devices were more successful than others.
Early injection techniques usually involved drilling a hole for each formation zone in a selected area. This horizontal expansion method of enhanced recovery is extremely expensive and time-consuming. A more economical method would entail servicing the various zones in a formation by way of multiple injection points in a single drilled hole.
A related patent, U.S. Pat. No. 4,248,302, answering the need for multiple zone injection from a single drilled hole was granted to Ronald K. Churchman and was assigned to Otis Engineering Corporation. Although particularly addressing pumpdown (through the flow line) completions, the patent does show using one or more side pocket mandrels to inject fluids and steam into one or more wells and/or formation zones. This method and apparatus was an advancement in the field of steam injection.
As interest in injection increased, several zones in a formation were serviced from a single drilled hole by utilizing concentric tubing. Such a configuration is shown in U.S. Pat. No. 3,319,717 by D. V. Chenoweth, U.S. Pat. Nos. 4,081,032, 4,099,563 and 4,399,865 by S. O. Hutchinson and G. W. Anderson and U.S. Pat. No. 4,081,028 by E. E. Rogers. All these devices allow steam or hot fluids to flow through the inner tubing to the next distributing apparatus while providing a passage for the steam or hot fluids to flow into the casing-tubing annulus and into a selected zone. While an improvement on multiwells, these devices did not allow the operator to deliver a calculated percentage of steam and hot fluid to a particular zone nor did they control the quality of the steam at several points in the well bore. Also the operator could not run maintenance tools down the tubing string to rework the downhole devices. Testing of this type of device showed that heat transfer between the concentric tubes created a heat loss from one tube to the other and created undesirable tubing movement. Chenoweth's U.S. Pat. No. 3,319,717 device was retrievable but had to be removed from the tubing string before any survey or maintenance tools could be run below the device. Oilfield operators wanted a system more controllable and more easily maintained.
U.S. Pat. No. 3,455,382 by D. V. Chenoweth solved part of the maintenance problem by injecting into different zones with a pressure regulator placed in a side pocket material. Tools to service the downhole devices could then be passed by the pressure regulators without removing them. The function of the pressure regulators was to keep the single phase injection fluids going through the exit port in the side pocket mandrel and into the tubing-casing annulus at a constant rate regardless of tubing pressure upstream or downstream of the pressure regulator. However, Chenoweth's device did not address the problem of providing a desired percentage of vapor and hot fluids to one or more separate formation zones. This device did not, because of its throttle-like action, allow the user to calculate a critical flow relationship utilizing known input pressures of injected fluid or steam. The present invention does allow the user to calculate a critical flow relationship and also has the advantage of having no moving parts.
SUMMARY OF THE INVENTION
The present invention includes an impingement means and other means within the flow passageway of a side pocket mandrel or other downhole tools to mix and direct the flow of steam and inject the steam into the formation. Steam is defined throughout this application to mean vapor and hot fluid or any combination thereof unless addressed separately as hot fluid or vapor. The steam is used to aid in the recovery of viscous petroleums, usually on the order of one to 1,000,000 centipoise at reservoir temperatures, by heating the petroleum with the steam.
The side pocket mandrel or other downhole tool is connected to a source of pressurized steam. The steam is pumped under pressure to the side pocket mandrel or other downhole tools through flow conductors. The steam as it leaves the source is mostly of a vaporous nature. As it travels through the flow conductors, it has a tendency to separate into a combination of vapor and hot fluid. A portion of this hot fluid including some vapor clings to the wall of the flow conductor in a more or less laminar manner while the remaining vapor continues down the center of the flow conductors.
In order to recombine the vapor and the hot fluid into a desired percentage of each, the impingement means mixes the two phases. This is accomplished in a chamber formed between the impingement means and the wall of the longitudinal flow passageway of the side pocket mandrel or other downhole tools. Primarily, hot fluid enters the grooves of the impingement means and is directed through the chamber formed by the impingement means and the wall of the longitudinal flow passageway of the side pocket mandrel body or other downhole tools by way of the radial directing means which in the preferred embodiment is a spirally-cut set of lands and grooves. The vapor phase of the steam flows into and is deflected by the fingers of the impingement means into the longitudinal flow passageway of the impingement means. These fingers also serve to guide tools through the impingement means. One or more holes through the wall in the impingement means allow the vapor to enter grooves formed on the outside diameter of the impingement means and the chamber formed between the outside diameter of the impingement means and the wall of the longitudinal flow passageway of the side pocket mandrel body or other downhole tools.
After mixing a percentage of the steam enters a value means which regulates the flow of steam into the tubing-casing annulus and into the formation zone through the perforations or flows out through drain holes in the impingement means to continue down toward other downhole equipment. The valve means could be, among other devices, a choke means. In the preferred embodiment, an offset choke means referred to as a valve means is used. Vapor and hot fluid that did not enter the chamber, as described above, flow through the longitudinal flow passageway and on to other downhole equipment.
The present device injects a preferred percentage of hot fluid and vapor into the formation zones at preselected intervals thus warming the viscous petroleum and enhancing its flow characteristics.
The impingement means can be placed in a downhole tool, other than a side pocket mandrel, that has a longitudinal flow passageway in which to place it. Flow of hot water and vapor could then be diverted percentage-wise by the impingement means into the ports provided in the downhole tool or on through the longitudinal flow passageway to other downhole equipment.
It is therefore one object of the present invention to provide an apparatus for enhanced oil recovery by steam injection.
It is a further object of this invention to provide an impingement means and, if desired, an agitation means in a side pocket mandrel or other downhole tools to inject a controlled percentage of hot fluid and vapor into a formation zone.
It is another object of this invention to agitate and recombine multiphased steam flow in a side pocket mandrel or other downhole tools using an impingement means and, in selected embodiments, an agitation means and/or a centralizer means.
It is yet another object of this invention to provide a centralizer means or an agitation means in a side pocket mandrel or other downhole tools that will also guide tools through the impingement means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B taken together constitute a longitudinal view, in section, showing the side pocket mandrel with a centralizer means, an impingement means and a valve means.
FIG. 2 is a longitudinal view, in section, showing an impingement means constructed in accordance with the present invention.
FIG. 3 is a top view of FIG. 2.
FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 1A showing a centralizer means located in the side pocket mandrel.
FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 1B showing the top view of an impingement means and a valve means seated in its pocket in the side pocket mandrel. The chamber formed between the outside diameter of an impingement means and the wall of the longitudinal flow passageway of the side pocket mandrel is also shown.
FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 1B showing the relationship of a port means, shown as holes, in the wall of an impringement means and the ports in the valve means in the valve pocket.
FIG. 7 is a longitudinal view, partly in section and partly in elevation, showing an agitation means as placed in an alternate embodiment of the invention.
FIG. 8 is a longitudinal view, partly in section and partly in elevation, showing a side pocket mandrel of a different design than that shown in FIGS. 1A and 1B.
FIG. 9 is a cross-sectional view taken along line 9--9 of FIG. 8 showing an oval or eliptical shaped mandrel configuration and the chamber formed between the outside diameter of an impingement means and the wall of the longitudinal flow passageway of this design side pocket mandrel.
FIG. 10 is a cross-sectional view taken along line 10--10 of FIG. 8 showing a round shaped mandrel configuration and the chamber formed between the outside diameter of an impingement means and the wall of the longitudinal flow passageway of this design side pocket mandrel.
FIG. 11 is a longitudinal view, partly in section and partly in elevation, showing an alternative embodiment of the invention with an agitation means placed in the belly of the side pocket mandrel.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1A and 1B, the side pocket mandrel 20 may have various round or nonround cross-sectional shapes. Although many cross-sectional configurations are available to one skilled in the art of side pocket mandrel design, the shapes most used are round, oval and elliptical. Two of these shapes are shown in FIGS. 9 and 10 which are examples of possible cross-sections of the side pocket mandrel shown in FIG. 8.
An upper crossover sub (not shown) with threads compatible with upper side pocket mandrel body thread 31 may be used to connect the crossover sub to the side pocket mandrel 40 if centralizer means 21 is not used. The crossover sub would also contain a thread similar to upper centralizer means thread 30 that would connect side pocket mandrel 20, by means of the upper crossover sub, to a source of pressurized steam (not shown).
As shown in FIGS. 1A and 1B, the centralizer means 21 is connected at one end to a source of pressurized steam by upper centralizer means thread 30 and is connected to one end of the side pocket mandrel body 40 by lower centralizer means thread 32 which is mated to upper side pocket mandrel body thread 31. This is another example of possible means to connect side pocket means 20 to a source of pressurized steam. The impingement means 22 is connected to the other end of the side pocket mandrel body 40 by the upper impingement means thread 34 mated with lower side pocket mandrel body thread 33. The lower impingement means thread 35 and thereby side pocket mandrel 20 can be connected to other downhole well equipment (not shown). One skilled in the art would realize that other connecting methods other than threads could be used.
Pressurized steam enters the centralizer means 21. Centralizer means 21 contains a second mandrel means 60 having a third longitudinal flow passageway 63 therethrough. The third longitudinal flow passageway 62, through which the steam flows, has its inner diameter reduced to form the venturi means 61 as shown in FIG. 1A. The venturi means 61 serves at least two functions. It provides for guidance of tools through the side pocket mandrel 20 and causes a pressure change and dispersion of the steam that passes through the venturi means 61.
The steam then enters side pocket mandrel body 40 by way of the first longitudinal flow passageway 41. As the steam flows from its source, it tends to form laminae (not shown) of various combinations of vapor and hot fluid. The recombination or remixing of the various phases and laminae of the steam is further accomplished by impingement means 22.
The impingement means 22 is shown in place in side pocket mandrel 20 in FIG. 1B, in an enlarged view in FIG. 2 and is shown in a top view in FIG. 3. The impingement means 22 includes a first mandrel means 50 having a second longitudinal flow passageway 51 therethrough and a helical directing means 52 which, in the preferred embodiment, is a set of spirally cut lands 91 and grooves 92 formed on the outside diameter 58 of the first mandrel means 50. The helical directing means 52 could be a set of threads of which several different configurations are available. Also included in the impingement means 22 is longitudinal directing means 53 which includes alternating fingers 54 and slots 55 on one end of the first mandrel means 50. In FIG. 2, a second port means 56, shown as holes through the wall of the first mandrel means 50, allows communication of steam between the second longitudinal flow passageway 51 and the first longitudinal flow passageway 41. Referring to FIGS. 5 and 6, the impingement means 22 also includes a third port means 57 for draining steam from the chamber 42 formed between the wall of the first longitudinal flow passageway 41 and the outer diameter 58 of the first mandrel means 50. The steam from chamber 42 flows back into second longitudinal flow passageway 51 of first mandrel means 50 through third port means 57 and out of side pocket mandrel 20.
As the laminae of hot fluid and vapor form of the surfaces of the equipment above impingement means 22, vapor also flows as a more or less separate phase down through the center of the longitudinal flow passageways. The laminae of hot fluid and vapor strike the fingers 54 and the slots 55 of the longitudinal directing means 53. The laminae of hot fluid and vapor are diverted or directed through slots 55 into chamber 42 and into the spirally cut lands 90 and grooves 91 of the helical directing means 52. As the vapor phase of the steam enters the second longitudinal flow passageway 51, part of the vapor enters chamber 42 and helical directing means 52 by way of the second port means 56. Part of the vapor is deflected into the second longitudinal flow passageway 51 by fingers 54 and continues to flow out of the side pocket mandrel 20 through the second longitudinal flow passageway 51 of impingement means 22.
As the laminae of hot fluid and vapor are directed helically around impingement means 22 and through chamber 42 by the helical directing means 52, the laminae meet and are mixed with the vapor phase of the steam entering the helical directing means 52 and the chamber 42 through second port means 56.
The shape, number and configuration of the fingers 54 and slots 55 of the longitudinal directing means 53; the size of the chamber 42; the number, location and size of second port means 56; the size and configuration of the lands 91 and grooves 92 of helical directing means 52; the size of first mandrel means 50; and the size, number and location of third port means 57 affect the quality or percentage of hot fluid to vapor that is mixed in chamber 42 and enters the fourth port means 45 once the hot fluid and vapor reaches the impingement means 22.
Communication from chamber 42 to valve pocket 44 is accomplished by the steam passing through fourth port means 45. The amount of steam entering first port means 46 is controlled by valve means 24 located in valve pocket 44.
Valve means 24 is comprised mainly of latch means 80, control means 81, seal means 82 and flow direction means 83. Latch means 80 allows for placement, removal and replacement of the valve means 24 by downhole wireline tools (not shown) familiar to those skilled in the art of placing and retrieving equipment with standard latch means. Valve means 24 is similar in construction to the chemical injection valve shown on page 6238 of the Otis Engineering Corporation section of the 1984-85 Edition of The World Oil Composite Catalog. The seal means 82 and the flow direction means 83 prevent the steam from entering the valve pocket 44 by any other path other than fourth port means 45 or leaving by any other path than first port means 46 by way of flow direction means 83. Flow direction means 83 can by a one-way valve to allow flow of steam in only one direction. Valve means 24 can be installed without flow direction means 83. First port means 46 could be fitted with a means to direct the flow of steam or with a venturi means to expand and dispense the steam. The steam is now able to enter the formation after passing through the perforations (not shown).
Other factors influencing the percentage or quality of the steam arriving at the first port means 46 include the quantity and quality (percentage of hot fluid to vapor) available at the side pocket mandrel 20 and the influences equipment above impingement means 22 has on the steam. In alternative embodiments of the invention, a centralizer means 21 and/or an agitation means 23 are utilized in the side pocket mandrel 20.
The centralizer means 21, previously discussed, may be placed in the side pocket mandrel body 40 in lieu of a crossover sub (not shown). The agitation means 23 can also be placed in the same location in the side pocket mandrel body 40 just as was the centralizer means 21. One of the alternative embodiments showing the agitation means 23 in place is shown in FIG. 7. Another alternative embodiment showing the agitation means 123 is shown in FIG. 11.
Referring to FIG. 7, agitation means 23 is comprised mainly of third mandrel means 70, fourth longitudinal flow passageway 71 and one or more sets of interior lands 72 and grooves 73. The sets of interior lands 72 and grooves 73 may be any design of land or groove familiar to those skilled in the art and, as shown in FIG. 7, may be helically-cut and threadlike in construction. They may also alternate in the direction of their spiral as shown in FIG. 7 or may be cut in the inside diameter of third mandrel means 70 in only one direction. Third mandrel means 70 is connected to side pocket mandrel body 40 by lower agitation means thread 36 which mates with upper side pocket mandrel body thread 31. Upper agitation means thread 37 is the means for connecting the other end of the third mandrel means 70 to the source of pressurized steam.
The agitation means 23 amalgamates the hot fluid and vapor in preparation for entering the impingement means 22 where the steam is further blended. As steam enters the third longitudinal flow passageway 62, the laminae of hot fluid and vapor are agitated by the lands 72 and the grooves 73 by turbulence and also by the alternating direction of flow caused by the reversed direction of the spiral formed by the lands 72 and grooves 73. The amalgamated steam then flows through the first longitudinal flow passageway 41 and on to the impingement means 22 as described above. The third mandrel means 70 may also be designed to provide guidance of tools through the side pocket mandrel 20 and especially through impingement means 22.
An alternative embodiment of side pocket mandrel 20 is side pocket mandrel 120 shown in FIG. 11. The flow and blending of steam to be provided to the formation is accomplished in much the same manner as the other embodiment except that the agitation means 121 is located lower in first longitudinal flow passageway 141 than the agitation means 23 was in first longitudinal flow passageway 41 shown in FIG. 7. This embodiment allows centralizer means 121, which is identical to centralizer means 21, to be utilized with agitation means 123. Centralizer means 123 is attached to side pocket mandrel body 140 in the same manner as described for centralizer means 23 in side pocket mandrel body 40. This combination of centralizer means 121 and agitation means 123 allows the user to enhance the mixing and blending of the steam if considered necessary to provide the selected or calculated quality or percentage of hot fluid and vapor to the formation. Impingement means 122 is identical to impingement means 22 and is attached to side pocket mandrel body 140 in the same manner as described for agitation means 22 in side pocket mandrel body 40.
The foregoing descriptions and drawings of the invention are explanatory and illustrative only, and various changes in shapes, sizes and arrangements of parts as well as certain details of the illustrated construction may be made within the scope of the appended claims without departing from the true spirit of the invention. | An impingement device in a side pocket mandrel or other downhole tools for injecting a predetermined quality of steam in one or more zones of a formation. The impingement device directs and mixes the laminae of hot fluid and vapor and a valve in a valve pocket controls the flow of steam to the zone from the side pocket mandrel or other downhole tools. Along with the impingement device, a centralizer to guide tools through the impingement device and to cause a pressure change and dispersion of the steam; and an agitation device to amalgamate the steam may be used if further blending is required. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hydraulic piston-cylinder-unit for a slewing drive, especially to swing working tools, with at least one piston, which can be slid in a cylinder and exhibits fastening means, by means of which the piston can be connected in such a manner to a coupling rod that the working tool can be swung by means of a movement of the piston.
2. Description of the Related Art
Hydraulic piston-cylinder-units are widely used to drive working tools, especially to swing backhoe and face shovels of dredgers. The DE-U-94 07 859 discloses a hydraulically driven dredging shovel, which can be arranged so as to swing on a carrier, arranged on the front end of the boom of a dredger. The swinging motion of the shovel is induced by means of a piston-cylinder-unit, which is arranged in a carrier, located in the upper rim area of the shovel. The carrier is connected to a coupling rod, with which the piston-cylinder-unit engages. The carrier is preferably shaped tubularly and contains the cylinder of the piston-cylinder-unit. Furthermore, the DE-U-296 21 253 discloses a slewing adapter to swing a tool, such as a dredging shovel, wherein the piston-cylinder-unit is envisaged in a coupling mechanism, which can be swung relative to the carrier of the construction machine. In this case, too, the piston-cylinder-unit is located preferably in a tubular carrier.
The end areas of the coupling rod are connected to the carrier of the construction machine and to the piston-cylinder-unit so as to swing. The connection to the piston-cylinder-unit is accomplished usually by means of an extension piece, which is mounted on the piston and which projects beyond the carrier, containing the piston-cylinder-unit.
Such an arrangement has the disadvantage that the extension piece cannot be mounted in principle until after the piston-cylinder-unit has been slid into the carrier. The result is a relatively low degree of prefabrication of the slewing drive, since the extension piece cannot be attached to the piston rod before the cylinder has been installed in a carrier.
SUMMARY OF THE INVENTION
The object of the present invention is to improve a piston-cylinder-unit for a slewing drive to the extent that it is easier to mount.
This problem is largely solved by a piston-cylinder-unit of the aforementioned kind in that the cylinder exhibits fastening means, by means of which the cylinder can be connected to the working tool or to a carrier of the slewing drive. The advantage herein lies in the fact that the extension piece can be mounted, for example, by screwing or welding before the piston-cylinder-unit is attached. The reason for this lies in the fact that, according to the invention, the cylinder of the piston-cylinder-unit is not slid into a carrier, but rather it itself functions as the carrier of the piston-cylinder-unit. This goal is reached in that the cylinder exhibits fastening means, by means of which it can be attached to the working tool or also to the carrier of the slewing drive.
Thus, it is no longer necessary to slide the cylinder into a carrier; and correspondingly it is possible to prefabricate the piston with extension pieces.
Furthermore, there are cost advantages in production, since the piston rod can be produced, according to the invention, as one piece with the welded extension piece. In addition it is possible to make the effective lengths smaller than in prior art slewing drives, since the narrower design of the welded extension piece makes it possible to use a correspondingly narrower cylinder. Another important advantage is the faster assembly and disassembly or the easy replacement of the piston-cylinder-unit.
A preferred embodiment of the present invention provides that the cylinder of the hydraulic piston-cylinder-unit is designed as a twin plunger cylinder. In this case a piston rod is used whose end regions can be moved in one of the end regions of the cylinder.
The chambers of the twin plunger cylinder that are provided at both faces of the piston and are pressure-driven can exhibit different diameters. The resulting advantage lies in the fact that forces can be introduced that vary with the piston's direction of motion in accordance with the different areas; and thus different velocities of the pistons can be realized. Such an arrangement is especially advantageous when the piston-cylinder-unit according to the invention is used with a grabber, since in this case different velocities are often necessary when opening or closing the grabber.
Another embodiment of the present invention provides that the fastening means of the piston are designed as an extension piece, which projects beyond the cylinder and to which the coupling rod can be attached so as to swing. The piston's movement in the cylinder leads to a corresponding movement of the extension piece connected to the piston, thus resulting in a corresponding swinging of the piston-cylinder-unit or a workpiece fastened thereto when the piston moves owing to the coupling rod, hinged to the extension piece.
In addition, the cylinder may exhibit one or several slotted recesses, through which the extension piece extends. The extension piece exhibits a cover element, by means of which the recess can be covered in all positions of the piston. The cover element can be screwed or also welded to the extension piece and serves primarily to prevent the piston-cylinder-unit from becoming dirty. In addition, it prevents an inadvertent engagement with the slotted recess of the cylinder.
According to a preferred design of the present invention, the extension piece is screwed or welded to the piston. One advantage of the welded design lies in the fact that a narrow extension piece can be used that in turn necessitates a narrow cylinder. Another advantage of welding lies in cost reduction. In both cases (screwed or welded) it is possible to attach the extension piece to the piston prior to installation of the piston-cylinder-unit. Especially in this case the resulting advantage is also that the piston-cylinder-unit of the invention can be quicky assembled and disassembled; and, when the requirements change, it can be easily replaced with a piston-cylinder-unit of a different design.
According to a preferred embodiment of the present invention, each opposite side of the piston exhibits one extension piece each, which extends radially from said piston. The resulting advantage lies in the fact that special tools, for example with several components, to be moved synchronously, such as grabbers, can be driven by means of the piston-cylinder-unit of the invention.
Another embodiment of the present invention provides that the piston of the hydraulic piston-cylinder-unit exhibits a cross borehole. In this case the coupling rods of a slewing drive are connected to the piston of the piston-cylinder-unit according to the configuration of the borehole.
Another embodiment of the present invention provides that the fastening element of the cylinder comprises straps, which have boreholes to mount the cylinder. In this case the straps can extend radially from the cylinder or can be configured at any other arbitrary position, for example in the bottom region of the cylinder. The straps are welded preferably to the outer jacket of the cylinder. The boreholes in the straps serve to connect the piston-cylinder-unit to a tool, for example to a shovel, or also to the carrier of the slewing drive.
It is especially advantageous if the cylinder of the hydraulic piston-cylinder-unit of the invention consists of two end members and at least one center member, which is connected to the end members so as to disconnect. Such a design of the cylinder offers the possibility of being able to select freely the length of the cylinder and thus also the slewing angle through the appropriate choice of the center member. The center member is flanged preferably to the end members.
The center member can exhibit the slotted recess, whose purpose serves the passing through of the extension piece of the piston.
Another embodiment of the present invention provides that the center member exhibits a strap, by means of which the piston-cylinder-unit can be swung in the carrier.
BRIEF DESCRIPTION OF THE DRAWINGS
Other details and advantages of the invention are explained in detail with reference to the embodiments depicted in the drawings.
FIG. 1A is a front view, which is a sectional view in part, of one embodiment of the piston-cylinder-unit with an extension piece.
FIG. 1B is a side view of the embodiment of FIG. 1 A.
FIG. 2A is a front view of an embodiment of the piston rod with two opposite extension pieces, which extend radially.
FIG. 2B is a side view of the embodiment of FIG. 2 A.
FIG. 3A is a longitudinal view of one embodiment of the piston-cylinder-unit with cross borehole.
FIG. 3B is a side view of the embodiment of FIG. 3 A.
FIG. 4A is a front view of one embodiment of the piston-cylinder-unit with flanged center member.
FIG. 4B is a side view of the embodiment of FIG. 4 A.
FIG. 5A is a front view of one embodiment of the piston-cylinder-unit with flanged center member, where the center member exhibits a strap to swing the piston-cylinder-unit.
FIG. 5B is a side view of the embodiment of FIG. 5 A.
FIG. 6A is a side view of a dredging shovel with the piston-cylinder-unit of the invention according to FIG. 1 .
FIG. 6B is a front view of a dredging shovel with the piston-cylinder-unit of the invention according to FIG. 1 .
FIG. 7A is a side view of a dredging shovel with the piston-cylinder-unit of the invention according to FIG. 3 .
FIG. 7B is a front view of a dredging shovel with the piston-cylinder-unit of the invention according to FIG. 3 .
FIG. 8 is a partial sectional front view of a grabber with a piston rod according to FIG. 2 .
FIG. 9 is a side view of the piston-cylinder-unit of the invention with grabber and
FIG. 10 is a cross sectional view of a grabber with several piston rod units.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood 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.
FIG. 1A is a front view, which is a sectional view in part, and a side view of a first embodiment of the piston-cylinder-unit 10 of the invention, where a piston 20 can be slid in the twin plunger cylinder 30 . The top side of the twin plunger cylinder 30 exhibits a slotted recess 33 , through which the extension piece 22 extends.
The extension piece 22 is screwed to the piston 20 . Said extension piece exhibits a borehole to receive a coupling rod, which is attached so as to swivel.
Furthermore, the extension piece 22 is connected to the cover element 24 , which is designed as a sheet metal strip. Thus, an unintentional engagement with the slotted recess 33 is prevented; and in all positions of the piston 20 dirt is effectively prevented from getting into the piston-cylinder-unit 10 .
FIG. 1B is a side view of the straps 32 , which are arranged on the outside of the twin plunger cylinder 30 and by means of which the piston-cylinder-unit 10 or the twin plunger cylinder 30 can be fastened. The straps 32 have vertical boreholes 34 . The straps 32 are welded to the twin plunger cylinder 30 .
FIG. 2A is a front view and FIG. 2B is a side view of another embodiment of the piston rod 20 , which exhibits two opposite extension pieces 22 ′ and 22 ″, which extend radially from the piston 20 . Each of the extension pieces 22 ′ and 22 ″ exhibits a borehole to receive a coupling rod. Such a piston rod 20 is provided, for example, for the special application with synchronously moved tools.
FIGS. 3A and 3B depict another embodiment of a piston-cylinder-unit 10 , in which the piston rod 20 can be slid in the twin plunger cylinder 30 . As evident from FIG. 3B, the piston 20 has two horizontally extending extension pieces 22 ′ and 22 ″, through which the borehole 23 extends. The bottom region of the twin plunger cylinder 30 has straps 32 to fasten the piston-cylinder-unit 10 , each of said straps exhibits a vertical borehole 34 .
FIG. 4A is a front view and FIG. 4B is a side view of one embodiment of the piston-cylinder-unit 10 of the invention, where the end members 36 , 36 ′ of the twin plunger cylinder 30 are connected together by means of a flanged center member 38 . The result is the possibility of making arbitrary adjustments to the length of the cylinder and thus also the slewing angle of the slewing drive through the choice of the center member 38 . According to FIGS. 4A and 4B, the piston 20 exhibits an extension piece 22 , for which the top side of the center piece has a corresponding recess 33 .
FIGS. 5A and 5B also depict an embodiment, where the end members 36 , 36 ′ of the twin plunger cylinder are connected together by means of the center member 38 . The flanged center member 38 exhibits the straps 50 , which exhibit a borehole and serve to pivot-mount the piston-cylinder-unit or an attached tool to a carrier. As already explained with respect to FIGS. 4A and 4B, the piston rod 20 exhibits an extension piece 22 , which extends through a slotted recess 33 of the center piece 38 .
FIG. 6A is a side view and FIG. 6B is a front view of a dredging shovel 70 . The dredging shovel 70 is connected by means of the straps 80 to a carrier 90 , for example, the dredger boom so as to swing.
The upper region of the dredging shovel 70 of the dredger has the invention's piston-cylinder-unit 10 , which is screwed to the dredging shovel 70 by means of the straps 32 . The extension piece 22 projects beyond the upper side of the piston-cylinder-unit 10 . Said extension piece is connected to the carrier 90 by means of coupling rods 40 , which are arranged to the right and left of said extension piece. A movement of the piston (not illustrated) by raising the pressure in the appropriate chamber of the twin plunger cylinder 30 results in a displacement of the extension piece 22 , which leads to the dredging shovel 70 being swung relative to the carrier 90 owing to the arrangement of the coupling rod 40 .
FIGS. 7A and 7B depict an arrangement of a dredging shovel 70 according to FIGS. 6A and 6B, where the embodiment of FIGS. 3A and 3B was used as the piston-cylinder-unit 10 . In this case the coupling rods 40 are attached to the extension pieces, which extend laterally from the piston. The coupling rods 40 are connected to the piston of the piston-cylinder-unit 10 so as to swing by means of a bolt, extending through the borehole 23 . As already explained in FIGS. 6A and 6B, the piston-cylinder-unit 10 is screwed by means of the straps 32 to said dredging shovel on the upper side of the dredging shovel 70 .
FIG. 8 depicts another embodiment of the invention, where a piston-cylinder-unit 10 is used, where the piston 20 is designed according to FIGS. 2A and 2B. Thus, the opposing extension pieces 22 ′, 22 ″ extend radially on two sides of the piston. Attached to said extension pieces by means of suitable boreholes are coupling rods 40 in order to drive the grab tongs 100 of a grabbing device synchronously.
FIG. 9 is a side view of a grabbing device with a piston-cylinder-unit 10 of the invention. The piston-cylinder-unit 10 comprises the piston 20 , which can move in the twin plunger cylinder 30 . Said piston exhibits the extension piece 22 , which is connected to two coupling rods 40 so as to swing. Furthermore, the half scoop 110 of the grabbing device is attached to the coupling rods 40 so as to swivel.
The top end region of the piston-cylinder-unit 10 exhibits straps 32 as the fastening means; said straps have boreholes 34 to mount the piston-cylinder-unit 10 on a carrier.
Furthermore, FIG. 9 shows that the bottom chamber of the twin plunger cylinder 30 exhibits a smaller diameter and thus a smaller cross sectional area than the chamber, bordering the piston 20 in the top end region of the twin plunger cylinder 30 . Different forces and speeds with respect to the up and down motion of the piston 20 and thus opening and closing of the half scoop 110 can be realized as a function of the different cross sectional areas.
FIG. 10 depicts an arrangement, wherein several piston-cylinder-units 10 of the invention are configured parallel to each other. Each piston-cylinder-unit 10 exhibits a twin plunger cylinder 30 , in which the piston 20 can be moved. From said piston extends radially the extension piece 22 , which is connected by means of the coupling rods 40 to the half scoop 110 so as to swing. For the sake of clarity the picture in FIG. 10 shows only one piston 20 with extension piece 22 and coupling rods 40 and only one half scoop 110 .
Each of the other half scoops (not illustrated) extends radially and outwardly from the individual piston-cylinder-units 10 . The individual piston-cylinder-units 10 are connected to each other or to a frame by means of the fastening means 120 .
In addition to the illustrated design with several piston-cylinder-units 10 it is also possible to use only one piston-cylinder-unit. Thus to be able to swing and simultaneously actuate many half scoops 110 , it is necessary in this case that the pistons 20 exhibit four radially extending extension pieces 22 , which are connected so as to swivel by means of coupling rods 40 to the appropriate half scoops 110 .
In addition to the illustrated embodiment of FIG. 10 that exhibits four piston-cylinder-units 10 , it is also possible to provide, as necessary, more or fewer piston-cylinder-units or half scoops.
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 recognized by one skilled in the art are intended to be included within the scope of the following claims. | The invention relates to a hydraulic piston-cylinder-unit ( 10 ) for a slewing drive with at least one piston, which can be slid in a cylinder and exhibits fastening means, by means of which the piston can be connected in such a manner to a coupling rod that the working tool can be swung by means of a movement of the piston. In accordance with the invention the cylinder exhibits fastening means, by means of which the cylinder can be connected to the working tool or to a carrier of the slewing drive. | 4 |
BACKGROUND OF THE INVENTION
The deposition and processing of refractory metal silicides has become the topic of many recent investigations due to their vital role in the future of very large scale integration (VLSI) technology. Initially, silicide films were intended to be used for the gate metallization in metal/oxide/semiconductor (MOS) devices. The next generation of silicide films will be used to shunt not only the gates of the MOS devices but the source and drain region as well, thus reducing their resistance. Silicide film structures for both the gate as well as the source and drain can be done in principle in a single processing step, giving rise to the process labelled self-aligned silicide formation. The self-aligned silicide formation process is done in a furnace sintering step by reacting the refractory metal film with the polysilicon film on top of the gate oxide and the bulk silicon at the source and drain regions, to form the refractory metal silicide film. The unreacted metal on the sidewalls is subsequently stripped away in a preferential etch that will not attack the silicide film. A serious problem with this technique as conventionally practiced relates to the fact that the diffusing species during the formation of many refractory metal silicides is silicon. Thus, during a sintering step at elevated temperatures which is required to form the desired silicide film, some silicide may form at the gate sidewall which will not strip in a preferential etch. This can result in an electrical short between the gate and the source and drain regions.
TiSi 2 is a suitable refractory metal silicide for self-aligned silicide applications for two reasons. One, it is the most conductive of all the refractory metal silicides. And two, it has the lowest temperature of formation. At the same time, however, there are problems associated with the sintering step between Ti and Si. Ti happens to be extremely sensitive to oxidation and this prevents the formation of high quality films. Also, some out-diffusion of the dopant from the source and drain regions through the silicide may take place because of the high temperatures involved in the sintering step, thus leaving high resistance shallow junctions.
Along another vein, in addition to the desire to be able to deposit a refractory metal to form a high-quality refractory-metal silicide, a need exists to be able to form high quality epitaxial silicon layers on silicon substrates as well as to be able to form high-quality oxides and nitrides on silicon substrates for a variety of purposes. The subject invention proposes a way to sputter such layers in an efficient fashion and in a manner in which the formed layers are of a relatively high quality.
SUMMARY OF THE INVENTION
An object of the invention is to be able to form titanium silicide on a silicon substrate in which the titanium silicide is fully reacted without the necessity of annealing or sintering the substrate after titanium or titanium silicide has been deposited on the substrate.
Another object of the subject invention is to be able to form a self-aligned MOS device in which the refractory metal is fully reacted to form a silicide without the necessity of annealing the MOS device after sputtering.
Another object of the subject invention is to provide an improved sputtering method which is relatively efficient in operations in which a chemical reaction is required between a sputtered material and the surface of a substrate.
Another object of the subject invention is to provide an improved sputtering method in which the substrate on which a material is to be sputtered is locally heated during sputtering.
The subject invention can be summarized as a method of depositing a material onto the surface of a substrate. The invention includes the steps of heating a substrate to increase the mobility of the sputtered species on the surface of the substrate to an energy level E s and sputtering the substrate with a sputtering material having a kinetic energy E k . The sum of E k and E s is sufficiently large to allow either: a chemical reaction to occur between the substrate and the sputtered material, a chemical reaction to occur between the sputtered material and a reactive gas present during sputtering; or an epitaxial layer to be formed on the surface of the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an Auger depth profile of a room-temperature deposited film of titanium silicide from a composite TiSi 2 .1 target;
FIG. 2 is an Auger depth profile for 600° C. substrate temperature deposited film of titanium silicide from a composite TiSi 2 .1 target (showing the exclusion of oxygen);
FIG. 3 is an Auger depth profile of the sample in FIG. 1 that has been subsequently annealed at 900° C. for 30 minutes in argon;
FIG. 4 is an Auger depth profile of the sample in FIG. 2 that has been subsequently annealed at 900° C. for 30 minutes in argon; and
FIG. 5 represents an Auger depth profile of titanium sputtered onto a silicon wafer at a substrate temperature of 515° C.
DETAILED DESCRIPTION OF THE INVENTION
As discussed above in the summary, the gist of the invention is that a substrate can be locally heated to increase the mobility of the species on a surface of the substrate during sputtering to promote certain desirable reactions to occur. This technique represents a novel approach over the prior art because prior-art sputtering was limited to substrate temperatures typically below 400° C.
Using the technique described herein, it is possible to heat the substrate to temperatures in a much higher range such as from 450° C. to 650° C. to allow a variety of desired reactions to occur. This technique is particularly applicable to magnetron sputtering techniques in which the sputtered material has a relatively high energy and is deposited at a relatively high rate. This is because the subject invention takes advantage of the enhanced mobility on the surface of the substrate due to the bombardment of the surface by the deposited species.
It is important to note that the formation of a reacted film during the deposition using the technique described herein takes advantage of the kinetics of the substrate surface. The average kinetic energy of the deposited species during sputtering is much higher than in either evaporation or chemical vapor deposition where only thermal energies are involved. The average kinetic energy is also a function of the sputtering power. When the sputtered species impinge on the substrate surface, some of their kinetic energy will be transferred to the surface species increasing their surface mobility and diffusivity. This in turn, corresponds to an equivalent surface temperature which is much higher than the bulk temperature of the substrate, thus promoting surface reactions which were only possible at much higher bulk substrate temperatures in the absence of surface bombardment. A manifestation of this effect was observed in the case of titanium silicide films deposited from a composite target and with substrate temperatures above 450° C. In this case, it was possible to obtain fully reacted titanium disilicide films similar to cold-substrate-deposited films that had been annealed at 900° C.
In the preferred embodiment, titanium is sputtered onto a silicon substrate. This embodiment is particularly important due to its applicability in self-aligned MOS structures. In this embodiment, the silicon wafer can be heated to a relatively high temperature typically in the range of 450° C. to 650° C. A titanium layer is sputtered to an approximate thickness of 600 to 1000 angstroms which results in the formation of a silicide layer of about 1000 to 2000 angstroms. By heating the substrate to a relatively high temperature, the titanium fully reacts with the underlying silicon during deposition to produce titanium silicide. The typical temperature at which fully reacted titanium disilicide is formed is above 500° C. The technique described herein represents an advantage over the prior art. This is because prior art titanium-deposition techniques previously required at least one annealing step to react the titanium with the underlying silicon. Another advantage over the prior art has to do with the purity of the titanium film. The technique described herein produces films which are oxygen free, oxidation resistant, and polycrystalline.
The reason for the exclusion of the oxygen from the growing silicide film seems to relate to the thermodynamics and phase equilibrium properties of the Ti-Si-O system according to some recent studies by the inventors. The formation of a titanium disilicide phase excludes the oxygen out of the growing film such that the only oxygen present is segregated in the form of SiO 2 on the surface of the titanium disilicide film.
In another embodiment of the subject invention, the sputtered material may be a composite of refractory metal and silicon. In a similar embodiment a refractory metal and silicon may be co-sputtered from separate targets onto a heated silicon substrate. In all of the above embodiments, the refractory metal can consist of titanium, tantalum, molybdenum, niobium, and tungsten. The refractory metal will react with the available silicon to form a silicide. This technique can be useful to form IC interconnects.
In another embodiment of the subject invention, silicon may be the sputtered material. In this type of embodiment, silicon would typically be sputtered onto a silicon substrate whose sputtering surface has been locally heated. The sputtered silicon will form a thin epitaxial layer of silicon. This embodiment has the advantage over the prior art because it can be done at bulk substrate temperatures which can be several hundred degrees lower than conventionally required.
The ability to grow epitaxial silicon on silicon or other substrate materials is of extreme technological importance. This is because such ability, in the case of epitaxial silicon on silicon, could prove to be useful for forming abrupt junctions in the underlayers of silicon devices. In the case of silicon on other substrates, one could possibly grow large-grain polysilicon on an insulator for applications in silicon on insulator (SOI) device technology.
In yet another embodiment of the subject invention, a substrate is locally heated, and a material is sputtered thereon in the presence of a reactive gas. For instance, silicon may be sputtered in the presence of oxygen or nitrogen to form good quality silicon oxide or nitride that could not be done according to prior art techniques for comparable bulk substrate temperatures. In a similar embodiment, a metal is used as the sputtering material in the presence of oxygen or nitrogen to form a metal oxide or nitride.
The ability to form a high quality silicon oxide is desirable as the intermetal dielectric in multilevel metal interconnects for integrated circuits. The ability to form high-quality metal oxides is desirable in a variety of applications such as dielectric insulation, and the ability to form high quality metal nitrides is desirable in barrier metal layers to prevent aluminum spiking in contact holes.
EXAMPLES
In one example, the films were sputtered in a bell-jar chamber which was fitted with two 2" DC magnetron sputter guns. The target was a cold-pressed target from Varian with a nominal composition of TiSi 2 .1. The system was pumped down to 3×10 -7 Torr before each deposition and then backfilled with ultra high purity argon to a pressure of about 3 mTorr. In order to clean the target and getter any background oxygen in the system, the target was presputtered for approximately an hour with the shutter closed before the deposition of the film. The substrates were (111), 10 ohm cm, bare silicon wafers. The heating of the wafers was done using a Mo resistor fabricated on the oxidized back of the wafers. This heating technique was chosen because it minimized the heating of other parts and fixtures in the sputtering chamber, which could degas and produce unwanted background gases. Using this technique it is possible to reproducibly heat the wafer between ambient and 650° C. The substrate temperature was measured on the front side of the wafer using a thin wire thermocouple via a spring contact. The sheet resistance of the films was measured using a four point probe and the thickness was obtained from a Dektak II stylus probe. The Auger signals were calibrated using TiSi 2 powder samples.
When the properties of a film deposited at 600° C. substrate temperature were compared to those of a film deposited on an unheated substrate, it was possible to find significant differences. The resistivity of the film deposited at room temperature was about 750 micro-ohm cm. Annealing produced a decrease in resistivity to about 20 micro-ohm cm. These numbers are typical of what has been reported in the literature.
On the other hand, the resistivity of the film deposited at 600° C. was 20 micro-ohm cm as deposited, and it did not change after the annealing cycle. This fact provides strong evidence that the film deposited using these elevated temperatures is fully reacted and requires no annealing.
X-ray diffraction data of the as-deposited film at room temperature and at 600° C. before and after annealing were taken. The room temperature as-deposited film appears to be amorphous. After annealing, a strong reflection due to the (004) TiSi 2 plane is observed indicating that the anneal has made the film polycrystalline with a preferred orientation, since no other strong peaks were discernable.
On the other hand, the 600° C. as deposited film is already crystalline and further annealing does not produce any changes. A noteworthy observation is that in all cases a preferred orientation was present (004) in the crystallized films independent of how the sample was crystallized. SEM examination of the as-deposited room-temperature film both before and after annealing showed a columnar structure on an otherwise smooth background with a feature size of about 1000 angstroms. Similarly, the as-deposited 600° C. film both before and after anneal was unchanged; however, it looked quite different in structure. The grain size was much larger, on the order of 6000-8000 angstroms, and as a result, it looked cloudy under visual observation.
Auger depth profiles were done on all the samples. The Auger profiling was done using Xe in order to detect any argon present in the films. However, no argon was detected in any of the films under the highest sensitivity of our system, which is about 0.1 atomic percent. Several authors have reported 1-5 atomic percent oxygen in titanium silicide films due to the high affinity of titanium for oxygen. As can be seen in 10 FIG. 1, this happens to be true in our room-temperature, as-deposited film, too. However, the as-deposited 600° C. film of 20 FIG. 2 has very little oxygen present in it. It is believed that the exclusion of the oxygen is due to the segregation of the contaminants from the reacted TiSi 2 film. In addition, this fully reacted film is more oxidation resistant than the room temperature deposited film as is seen by the results 30, 40 of FIGS. 3 and 4. In the room temperature film, annealing converted the top third of the film into a mixture of titanium, silicon and their respective oxides, while the oxide present on the surface of the 600° C. substrate temperature film, both before and after anneal is SiO 2 . This fact is highly desirable from a processing point of view. It is also consistent with a recent study which shows that the only stable oxide that can co-exist with TiSi 2 is SiO 2 from thermodynamic phase diagram calculations.
In a second example, titanium was sputtered on a silicon wafer at a substrate temperature of 515° C. Approximately 600 angstroms of titanium was deposited on the wafer. The resulting film was a matte shiny surface with a resistivity of 15 micro-ohm cm which is the lowest value reported for a titanium disilicide film. The film thickness was assumed to be the thickness measured after etching a step in an HF etch, which was 1000 angstroms. An Auger depth profile 50 of the as-deposited film is given in FIG. 5. As can be seen, the resulting film is not a titanium film on silicon but a titanium silicide film with an approximate composition of TiSi 2 . Furthermore, the film contains no Auger detectable oxygen or carbon. Titanium silicide, and titanium films deposited in this system onto room temperature substrates typically show 5-7 atomic percent oxygen incorporation. After the deposition, the film was placed in a selective titanium etch (NH 4 OH/H 2 O 2 /H 2 O: 1/1/5 at 85° C.) and the thickness was remeasured. This resulted in no loss of film thickness indicating that the entire titanium film was consumed by the growing titanium silicide film during deposition. Further, annealing of this film at 900° C. for 30 minutes, in argon, resulted in no change in resistivity or thickness. A subsequent Auger depth profile showed no changes except for some SiO 2 growth on the surface.
Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation; the spirit and scope of this invention being limited only by the terms of the appended claims. | The subject invention is a method of sputtering a material on a substrate in which the substrate is first locally heated so that the mobility on the surface of the substrate is increased to a value E s . A material is then sputtered on the substrate with a sputtering energy E k whereby the sum of E k and E s is greater than the activation energy required for a chemical reaction to occur between the sputtered surface of the substrate and the sputtered material. In the preferred embodiment, the substrate is silicon and the material to be sputtered is a refractory metal such as titanium. | 2 |
FIELD OF THE INVENTION
The present invention generally relates to aviation electronics, or avionics, and more particularly relates to multi-card avionics boxes, and even more particularly relates to a system and method for extracting circuit cards from avionics boxes having blind mated circuit cards therein.
BACKGROUND OF THE INVENTION
In the past, designers of avionics systems have endeavored to provide systems with improved reliability and improved serviceability. One crucial element in such systems has been the use of spare component parts, including field replaceable spare circuit cards. These field replaceable circuit cards allow for repair of avionics equipment without extended downtimes which are often associated with sending an avionics LRU to a service center for repair. One common method of assisting in quick removal of circuit cards has been the use of pivoting cam extractors, which are attached to the circuit card and pivoted to create a camming action, causing motion of the circuit card away from a connector in the LRU.
While these pivoting camming extractors have many advantages, often including low cost and ease of manufacture, they also have significant drawbacks.
First of all, the pivoting camming extractors often result in extraction or insertion forces which have significant components in directions other than the desired direction of insertion or extraction.
Secondly, the insertion and extraction forces often approach or exceed the force limits of these cam extractors, especially with circuit cards having high pin counts and limited displacements. Consequently, there exists a need for improvement in systems and methods for inserting and extracting circuit cards.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide enhanced reliability for avionics boxes having extractable circuit cards therein.
It is a feature of the present invention to include a multi-tooth rack and pinion arrangement.
It is an advantage of the present invention to reduce the undesired extraction forces in a direction other than the primary direction of travel of the circuit card during the insertion and/or extraction process.
It is another advantage of the present invention to increase the mechanical advantage of the extractor for generating strong insertion and extraction forces required for circuit cards with high pin counts, and at the same time, maintaining or increasing the displacement insertion or extraction.
It is yet another advantage of the present invention to improve the reliability of avionics boxes by reducing pin damage during insertion.
The present invention is an apparatus and method for inserting circuit cards in circuit card cases, such as, but not limited to, avionics LRUs, which are designed to satisfy the aforementioned needs, provide the previously stated objects, include the above-listed features, and achieve the already articulated advantages. The present invention is carried out with a “cam-less extractor” in a sense that the amount of undesired pivoting of the circuit card during insertion and extraction has been greatly reduced.
Accordingly, the present invention is a system and method for inserting and extracting circuit cards from a case by use of a multi-toothed rack in association with a pivoting toothed member.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may be more fully understood by reading the following description of the preferred embodiments of the invention, in conjunction with the appended drawings wherein:
FIG. 1 is a simplified perspective diagram of an extractor and environment of the prior art.
FIG. 2 is a perspective view of a pair of extractors of the present invention, together with the environment in which they would be used.
FIG. 3 is an enlarged perspective view of an extractor of the present invention in a disengaged state.
FIG. 4A is a side view of an extractor of FIG. 2 shown disposed in a disengaged state.
FIG. 4B is a side view of an extractor of FIG. 2 shown disposed in a state intermediate of that shown in FIGS. 2 and 3, and intermediate of that shown in FIGS. 4A and 4C.
FIG. 4C is a side view of an extractor of FIG. 2 shown disposed in a state intermediate of that shown in FIGS. 2 and 3, and intermediate of that shown in FIGS. 4B and 4D.
FIG. 4D is a side view of an extractor of FIG. 2 shown disposed in an engaged state.
FIG. 5 is a cutaway view of portions of an aircraft of the prior art.
DETAILED DESCRIPTION
Now referring to the drawings, wherein like numerals refer to like matter throughout, and more particularly to FIG. 1, there is shown a system of the prior art, generally designated 100 , which includes a circuit card 101 for insertion into an avionics box, not shown. A lever handle 102 is coupled through lever handle pivot pin 104 to circuit card 101 , and a camming action occurs when lever handle 102 pivots about lever handle pivot pin 104 and lever handle tooth 106 engages chassis rack 110 with a chassis rack tooth 112 thereon. These camming extractors are well known in the art.
Now referring to FIG. 2, there is shown an avionics box 200 of the present invention having a chassis slot 220 therein for coupling with a circuit card 201 . Coupled to circuit card 201 is a lever handle 202 . FIG. 2 shows the circuit card 201 having bottom and top extractors which are preferably identical to each other and are disposed adjacent to avionics box bottom 226 and avionics box top 228 respectively. The description herein is equally applicable to either the top or bottom of circuit card 101 . Lever handle 202 pivots about lever handle pivot pin 204 , thereby causing lever handle first tooth 206 to interact with chassis rack member 210 and chassis rack member first tooth 212 thereon. Circuit card 201 is shown in a chassis slot 220 . Two chassis slots are shown; however, it should be understood that numerous chassis slots may be included depending upon the particular design requirements. Circuit card 201 slides through a rack slot 222 , which is an interstice between adjacent chassis rack members 210 and then is further slid into chassis slot 220 .
Now referring to FIG. 3, there is an enlarged perspective view of the apparatus of FIG. 2, showing additional detail. The apparatus is shown in a disengaged state, meaning that the circuit card 201 is free to slide in chassis slot 220 because there is no contact between lever handle first tooth 206 , lever handle second tooth 207 , and lever handle third tooth 208 and the chassis rack member 210 . Together lever handle first tooth 206 , lever handle second tooth 207 , lever handle third tooth 208 , and lever handle 202 may be viewed as a pinion for cooperation with a rack. Chassis rack member 210 is shown having a chassis rack member first tooth 212 , which is preferably wider than chassis rack member second tooth 214 and chassis rack member third tooth 216 . The purpose of the extra width of chassis rack member first tooth 212 is to assure that proper alignment of lever handle first tooth 206 occurs with respect to the chassis rack member 210 . Chassis rack member first tooth 212 is of sufficient girth that it will mesh with initial lever handle gap 209 , but it will not mesh with second lever handle gap 211 . This prevents a situation where circuit card 201 might otherwise be inserted into chassis slot 220 while lever handle 202 is already disposed in a partially closed orientation where one of lever handle second tooth 207 or lever handle third tooth 208 might have been the initial gear tooth which meshes with chassis rack member 210 . This would typically result in an insertion of circuit card 201 to a point which is less than a normal full insertion. Chassis rack member fourth tooth 218 is included for assistance in extraction of said circuit card 201 . Lever handle first tooth 206 , lever handle second tooth 207 , and lever handle third tooth 208 may have a lever handle gear tooth width dimension 224 which is in excess of a width characteristic of rack slot 222 , so that lever handle first tooth 206 , lever handle second tooth 207 , and lever handle third tooth 208 are capable of engaging adjacent chassis rack members 210 (see FIG. 2 ). Circuit card 201 has a predetermined level of insertion forces and displacement necessary to fully insert circuit card 201 via chassis slot 220 into avionics box 200 . The pitch radius 230 is designed to provide the appropriate level of mechanical advantage to result in the necessary insertion forces. The dimensions of lever handle radius 232 and pitch radius 230 are effectively matched to the predetermined level of necessary insertion forces for said circuit card 201 .
In operation, and now referring to FIGS. 4A-4D, the present invention operates as follows:
Circuit card 201 is inserted into chassis slot 220 with lever handle 202 disposed as shown in FIG. 4 A. Lever handle first tooth 206 is not yet meshed with chassis rack member 210 . As lever handle 202 is progressively raised through positions shown in FIG. 4 B and FIG. 4C, circuit card 201 is caused to translate along chassis rack member 210 until it reaches its desired location when lever handle 202 is disposed as shown in FIG. 4 D. The details of dimensions and relative locations of the various parts of the apparatus of the present invention are expected to be tailored in well-known ways to accommodate predetermined levels of insertion forces and predetermined levels of mechanical advantage and displacement.
Now referring to FIG. 5, there is shown a cutaway view of an aircraft of the prior art, generally designated 500 , having a cutaway portion 501 exposing a structural frame 502 and an avionics rack 504 having at least one avionics receiving station 506 therein for receiving a typical avionics line replaceable units (LRUs) or an avionics box 200 of the present invention, which preferably has connectors thereon which are similar, if not identical, to connectors for coupling prior art avionics LRUs with avionics rack 504 . The present invention is described herein in an aviation and avionics environment because it is believed that the beneficial aspects of the invention will be readily appreciated in such an environment. However, it should be understood that the circuit card insertion apparatus and slots, etc. of the present invention, can be used in any type of electronics equipment, and it is the intention of the present invention to include these other non-avionics equipment types.
It is thought that the method and apparatus of the present invention will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construct steps, and arrangement of the parts and steps thereof without departing from the spirit and scope of the invention or sacrificing all of their material advantages. The form herein described is merely a preferred exemplary embodiment thereof. | An avionics LRU having multiple circuit cards therein which are arranged in readily accessible slots and have insertion/extraction apparatuses coupled thereto which use a rack and pinion arrangement to provide a relatively high insertion force over an increased displacement. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the treatment of a waste water stream containing water, oil, sand, oily sand and gas to separate the oil, sand, gas and water out of the waste water stream. In particular, the present invention is related to a method and apparatus for use on offshore and onshore oil and gas well drilling operations whereby the water and sand can be purified to a point at which it can be released into the environment without damaging the environment.
2. Description of the Prior Art
Most oil and gas wells both onshore and offshore produce a large amount of waste water which commonly contains oil, gas and sand. The sand contained in the waste water stream frequently is contaminated or soaked with oil to the extent that the sand cannot be discharged into the environment because of the environmentally dangerous levels of oil contained in the sand. Most state and federal regulations now require that waste water and sand discharge into the environment meet certain maximum limitations on the amount of oil contained therein.
Numerous methods have been proposed for treatment of waste water streams for removal of pollution therefrom. Typical of these methods are the following:
U.S. Pat. No. 4,198,300 discloses an apparatus for removing suspended oil droplets from water, including a vertical pipe suspended from an offshore oil platform partially submerged in the sea surrounding the platform, a means for injecting a wast water stream into the middle portion of the pipe and a means for injecting gas into the lower portion of the pipe and for diffusing the gas to disperse the gas into gas bubbles, so that the gas bubbles counter currently contact the waste water stream as the gas bubbles rise to the upper portion of the pipe, thereby attaching the oil droplets and reducing the overall density of the oil droplets efficiently so that the upper velocity of the oil droplets is greater of the downward velocity of the waste water stream and promoting the separation of oil droplets from the waste water stream, and means for withdrawing the oil droplets from the upper portion of the pipe. The apparatus uses natural gas air or inner gas as the gas medium for forming the gas bubbles.
U.S. Pat. No. 4,221,671 discloses an upright circular tube settler with stacked tube modules for removal of solids from fluids and for removal of one fluid from another. The tube modules are for use in a tube settler of the type having vertically disposed concentric tubular walls. The modules contained concentric rows of essentially straight fluid flow passages open at both ends, the passages in each row of a particular model being tilted relative to the vertical in the same direction and to substantially the same degree, the passages in each row being skewed in relation to other passages in the same row of the same tier. The passages cooperate to provide means for directing fluid in a substantially spiral path around a tank.
U.S. Pat. No. 4,217,211 discloses a sewage treatment process wherein sewage is passed into deep underground shaft and is improved by passing a liquor of the sewage in the underground shaft through an inner shaft which extends only part way down into to the underground shaft. A mixing shaft and liquor nozzles are provided for receipt of the sewage liquor passing downwardly. The action of the decending liquor through the nozzles entrains ascending liquor from the shaft into the descending liquor resulting in re-circulation which allows extended contact time of the liquor with a microorganisms used to digest the sewage.
U.S. Pat. No. 4,186,087 discloses a method and apparatus for separating substances from liquids by flotation using bubbles comprising adsorbing a substance present in a liquid on bubbles, floating the bubbles adsorbing the substance and separating the substance from the bubbles, characterized by allowing the bubbles adsorbing the substance to ascend through a fluid route in a tube independent of the ambient turbulently flowing liquid and then collecting and separating the substance from the liquid at the upper end of the tube. The apparatus includes a vertical column provided at the bottom with a gas-diffusing means and a tube placed inside the vertical column, the tube being provided with a means for collecting bubbles at the lower end and concentrating in the collected bubbles at the upper end.
U.S. Pat. No. 4,066,540 comprises a vertical column for continuous froth flotation having therein a froth separator, a raw water inlet pipe, a treated water discharge pipe and gas dispersing unit, and stepped shelves disposed inside the column and adapted to provide thorough contact between the bubbles and water subjected to treatment.
U.S. Pat. No. Re. 28,378 discloses an apparatus for effecting purification of liquids by flotation wherein a mixture of gas in liquid is subjected to sufficient pressure for the gas to dissolve in the liquid and to form a solution of the gas in the liquid. The solution is introduced into a flotation tank and pressure is lowered to form gas bubbles in the tank at a slow rate, thereby forming very small bubbles. The slow rate at which the very small gas bubbles are formed provides purification of polluted liquids by flotation.
U.S. Pat. No. 3,893,918 discloses a method for separating materials leaving a well including utilizing an elongated separater conduit partially above and below the surface of a body of water to establish a fluid column in the water, supplying an oil containing fluid mixture in the fluid column and causing the fluid to float downwardly through a flowing zone over a plurality of baffle means to induce coalescent separation of oil from fluid, intermittently interrupting the supply of fluid to impede the downward velocity of fluid for a time sufficient for oil to rise from the flowing zones into the quiescent zones defined by the baffles, flowing oil accumulated in the quiescent zones upwardly to establish as upper layer of oil in the fluid column, flowing oil accumulated in the lower quiescent zones through the upper quiescent zones, withdrawing oil from the upper oil layer, and flowing the oil free liquid from the exit zone of the separator from the body of water beneath the surface thereof.
U.S. Pat. No. 3,520,415 discloses a separation vessel disposed in a vertical columm for separating a hydrocarbon material from a slurry of water, bitumen, and sand. The vessel includes an impeller mechanism, a sand settling zone, and a froth dis-engaging zone. A set of turbulence reducing baffles is mounted between the underwash sparger and the froth withdrawal conduit.
U.S. Pat. No. 2,806,599 discloses a vacuum control for gravity separators utilized for effectively recovering extremely fine fractions of sand suspended in water utilizing a low pressure cyclone gravity separator whereby fluids are spiraled about in a cyclone in a circular manner to separate solids such as sand from the fluids.
U.S. Pat. No. 2,754,970 discloses a fluid separator for separating solids or liquid particles from fluids. The separator is disposed in a vertical manner and contains no moving parts. The fluid is helically whirled in a stream so that the particles become centrifugally concentrated in the outer peripheral regions of the stream, the fluid stream opening tangentially into the upper end of a vertical casing, a well inside with the lower end open to the interior of the casing and upper open exterior of the casing, means in the well for impressing a helical path upon the fluids stream passing from the bottom to the top of the well, and an ejector zone intermediately at the end of the well.
U.S. Pat. No. 1,869,241 discloses a vertical apparatus for the separation of the solid substances, such as for separating the graphite from its ore by the emulsion process. The fluid flows through a central pipe and into a series of baffles to effect separation of solids from the fluid.
U.S. Pat. No. 1,458,805 discloses an apparatus for the settlement of solid particles in suspension in liquids and discloses a vertical column having a series of baffles therein, and a number of parallel sloping settling surfaces separated by similar settling spaces to separate particles from a liquid stream flowing therethrough.
U.S. Pat. No. 359,357 discloses a process and apparatus for refining hyrocarbons which includes a vertical column having an inclined spiral plate over which the fluids are flowed.
The above patents disclosed various separation and flow treatment devices but none show the novel combination of elements provided for separating oil, gas, sand and water in a waste water stream disclosed in the present invention.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided an apparatus for separating oil, gas and sand from a waste water stream and for separating oil from oily sand and the waste water stream including an upper oil manager assembly for collecting and conveying oil separated from a waste water stream, a sand helix assembly connectable to the upper oil manager assembly for separating sand particles and oil particles from a waste water stream, a sand manager assembly connectable to the sand helix assembly for collecting sand separated from the stream of waste water and removing oil from the sand, a flow control assembly connectable to the sand manager assembly for controlling the flow of oil, water and sand through the apparatus, a lower oil manager assembly connectable to the flow control assembly for receiving oil and transferring oil to a storage facility outside of the apparatus, and an oil helix assembly connectable to the lower oil manager assembly for separating oil from the waste water stream.
The present invention has the advantage over the prior art of much more thoroughly cleaning a waste water stream. Furthermore, the invention can be made in module form so that the degree of cleanliness of the effluent can be varied depending upon the number of sand helix and oil helix modules added to apparatus.
In addition, the present invention can remove oil from sand to a higher degree of purity, thereby enabling sand previously contaminated with oil to be discharged into the environment without damaging the environment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic elevational view, partially in section, showing an offshore production platform including the separation apparatus of the present invention;
FIG. 2 is a schematic elevational view, partially in section, showing an oil helix module of the present invention;
FIG. 3 is a cross-sectional view taken along lines 3--3 of FIG. 2;
FIG. 4 is a schematic, partially cross-sectional view of the water works executive or flow control assembly of the present invention;
FIG. 5 is a schematic elevational view, partially in section, of the sand manager of the present invention taken along lines 5--5 of the FIG. 6;
FIG. 6 is a cross-sectional view of FIG. 5 taken along lines 6--6 of FIG. 5;
FIG. 7 is a schematic elevational view, partially in section, showing a sand helix module of the present invention;
FIG. 8 is a cross-sectional view taken along lines 8--8 of FIG. 7;
FIG. 9 is a schematic elevational view, partially in section, showing the upper oil manager of the present invention, and
FIG. 10 is a schematic elevational view, partially in section, showing the lower oil manager of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, in FIG. 1 is shown the separator of the present invention generally indicated by the numeral 20 connected to offshore platform 22 located in a body of water 24 in a manner similar to that described in U.S. Pat. No. 4,198,300. Platform 22 is a fixed, bottom supported structure typical of those used for offshore drilling and production and is fabricated from a plurality of welded members including legs 26, cross braces 28 and diagonal braces 30. The structural members provide the platform with the strength necessary to support platform deck 32 and withstand the wind, waves and sea current encountered in an offshore environment.
As shown in the drawing, platform 22 is a production platform capable of treating and storing the fluids such as oil and gas produced from a nearby offshore field. Rising from the sea floow 34 are a series of well pipes or conductors 36 which transport oil and gas produced from several well sites located within the offshore field. Platform 22 serves as a centralized collection and processing facility for the field.
Since fluids produced from oil fields frequently contain significant quantities of water in addition to oil and gas, the production facility must be equipped to segregate the oil, gas and water mixtures into their constituents. Platform deck 32 is shown in the drawings equipped with the components and apparatus necessary to substantially separate the produced fluids. Fluids from the well pipes 36 flow into gas separator 38 which separates the fluids into their liquid and gaseous components. Separator 38 is essentially a high pressure settling tank which permits the lighter hydrocarbon components, primarily methane, to flash off and separate from the heavier liquid components and to be withdrawn through gas line 40.
Liquid components from separator 38 then enter treater 42 which separates the liquids into an oil stream 44 and a waste water stream 46. Pump 44a pumps the oil stream 44 to land or a reservoir through pipeline 44b. Treater 42 is typically a heater-treater which simultaneously heats and separates the oil and waste water mixture. The application of heat to the liquid stream assists in destabilizing the oil-water mixture. Demulsifying agents can also be added at this point to help break any oil-water emulsion which may have formed as a result of excessive mixing of the oil and water components. The separation unit of the treater may consist of a combination of weirs, coalescers, baffles and skimmers which serve to gravitationally separate the oil-water mixture.
Normally, treater 42 can substantially separate the oil-water mixture. However, such separation equipment at best will typically discharge a waste water stream which contains anywhere from 200 to 1000 parts per million of oil. Since the waste water effluent from an offshore rig must ultimately be discharged into the sea and the waste water from an inland rig must be discharged onto land, the oil content of the effluent has to be reduced even further to satisfy environmental regulations.
The apparatus and method of the present invention are employed to provide the necessary secondary treatment to waste water stream 46 to reduce its oil content and the amount of oil on sand to an environmentally acceptable level and to maximize recovery of oil from the offshore field. The separator apparatus of the invention is generally indicated by the numeral 20 and is vertically positioned in platform 22. As can be seen in FIG. 1, separator 20 extends from the position above the surface of the sea to a position substantially below the surface. Separator 20 should be securely attached to or supported by platform 22 so that it remains in a stable position even when under the influence of strong wind, wave or current action. For example, separator 20 can be bolted or welded to the legs and braces 28 and 30 to provide the necessary structural support.
It should be noted that for purposes of the present invention, platform 22 to which separator 20 is secured need not be a fixed, bottom supported platform of the type shown in the drawings. Separator 20 can be supported by any type of offshore rig or structure which can be used for oil and gas production purposes. Such offshore rigs include conventional offshore production structures such as jackup rigs, concrete platforms, monopods and guyed towers. Moored production vessels adjacent buoyed production risers can serve to support the apparatus of the present invention. Furthermore, the separator of the invention could be utilized above sea level or onshore just as effectively.
The lower end of separator 20 is typically open to the sea at the bottom end 90 to permit the discharge of clarified waste water. If the separator were being used on land, a pipe or hose could be connected to lower end 90 to convey clarified waste water to any desired location. Gas is supplied to separator 20 from gas line 40 and waste water is supplied to separator 20 by line 46.
Separator 20 is composed of several separate components. These components include, beginning at the top of the embodiment of the separator shown in FIG. 1, an upper oil manager generally indicated by the numeral 60 in FIGS. 1 and 9 which collects oil from the sand helix 48 and conveys it to the lower oil manager 54; a sand helix generally indicated in FIGS. 1, 7 and 8 by the numeral 48 which processes the total water stream, separating solid (sand) particles from the oil-water stream in a counter current fashion, and separating some oil from the stream; a sand manager generally indicated in FIGS. 1, 5 and 6 by the numeral 50 which collects sand particles separated from the stream of water by the sand helix in a reservoir contained therein for further treatment; a water works executive generally indicated in FIGS. 1 and 4 by the numeral 62 which includes the controls, valves, meters and the like to control the oil, water, gas and sand flow between the various components; a lower oil manager generally indicated by the numeral 54 in FIGS. 1 and 10 for transferring oil upward to a reservoir; and an oil helix generally indicated by the numeral 52 in FIGS. 1, 2, and 3 which processes the total water stream and separates oil from the stream in a counter current fashion.
In the embodiment shown in FIG. 1, all of the components are utilized in combination. However, various subcombinations of the various components could be utilized under certain conditions. When it is desired to treat water containing oily sand, gas, and free oil to a point such that all particles greater than 50 microns in size have been removed, one should utilize the sand helix, sand manager, water works executive, oil helix, and oil managers. If it is desired to treat water containing free oil but a negligible amount of sand to a point where the particle size of any particle in the stream is less than 50 microns, one could utilize only the oil helix, the water works executive, and the oil managers.
It can thus be seen that the separator referred to generally by the numeral 20 may contain a combination of the above components necessary to treat the contaminated water in a single, vertical, cylindrical enclosure or casing indicated by the numeral 58. The following is a description of the complete system containing all the components for treating water containing oily sand, gas, and free oil.
The separator containing the complete system is shown in FIG. 1 and is generally indicated by the numeral 20. At the top end of the vertical enclosure 58 containing the complete separator system 20 is the upper oil manager generally indicated by the numeral 60. The upper oil manager 60 receives oil from the sand helix modules 48 below and contains a weir mechanism for controlling the level of the oil therein. As can be seen in FIG. 9, the weir mechanism includes an inverted cone 250 having a vertical pipe 252 extending upward therefrom. Cone 250 and pipe 252 are connected to the central conduit generally indicated by the numeral 47, which extends downwardly throughout substantially the entire length of separator 20. All of the various elements and modules are vertically aligned and centered on central conduit 47, which is preferably composed as a series of pipes, connected by flanges such as flanges 72 shown in FIG. 9. Oil flowing upwardly from each of the sand helix modules 48 through one of the pipes 48a continues upwardly through cone 250 and pipe 252, where the oil then overflows into the space or collection reservoir 254 between the inside of conduit 47 and the outside of cone 250 and pipe 252. The oil in collection reservoir 254 is transferred to lower oil manager 54 by pipe 256. The oil traveling downwardly through pipe 256 is driven by gas under pressure in the chamber or space 258 in the top of separator 20.
Waste water stream 46 (see FIG. 1) enters the separator at the executive 62 and is conveyed upwardly through pipe 270. The mixture of gas, oil, sand, and water enters header 272, which is a circular pipe having holes 273 therein. The mixture of gas, water, oil, and sand is sprayed from the header through holes 273 to effect separation of gas therefrom. The mixture of oil, water, and sand falls into the space generally indicated by the numeral 274 between the outside of central conduit 47 and the inside of cylindrical enclosure 58.
Located immediately below the upper oil manager 60 are the sand helix modules generally indicated by the numeral 48 as shown in FIGS. 1, 7, and 8. The sand helix modules 48 are contained within casing 58 and include an outer shell 64 which is generally cylindrical in shape. The bottom of the outer shell 64 is open and has connected thereto a top 66 shaped like a truncated cone.
Located in the center of shell 64 is central conduit 68 which is a continuation of central conduit 47 and is connected thereto by flange 72. Pipe 68 contains smaller pipes 48a, 88a, 256 and 270 for transferring fluids between the various components or stages of separator 20. Flanges 72-72 are located at the top and the bottom of the sand helix module for attaching a series of sand helix modules together or for attaching the sand helix module 48 to another component. The top 66 is rigidly secured to central conduit 68 to prevent any fluid from escaping upwardly between top 66 and central conduit 68.
Located between central conduit 68 and shell 64 are a series of helical vanes 74 held in place by a series of concentric horizontal rings 76. The rings are in turn supported by a series of concentric cylinders 78 to which the horizontal concentric rings 76 are attached. The inner most concentric ring 80 is connected to central conduit 68.
The helical vanes 74 have a bottom edge 82 and a top edge (not shown) which are generally in alignment with the top and bottom end of outer shell 64. The vanes extend from the top to the bottom of shell 64 in a spiral manner. In the embodiment shown in FIGS. 7 and 8 the helical vanes 74 are contained in three chambers formed by the two concentric cylinders 78. The number of chambers and number of vanes may be varied as desired. The length of the vanes can be varied as desired to achieve the desired flow pattern.
In lieu of vanes, helical tubular pipes (not shown) can be aligned similarly to vanes 74 and held in place by a series of concentric horizontal rings 76 (or other suitable means), generally aligned with top and bottom end of outer shell 64.
Connected to the upper end of central conduit 68 and beneath the conical top 66 is a baffle 84. Beneath baffle 84 is a hole 86 for intake of oil separated from the water, sand, and oil slurry entering the base of sand helix 48. Any oil which happens to separate in the sand helix 48 enters pipes 48a contained inside of central conduits 68 and 47 through hole 86 and is conveyed upwardly to the upper oil manager 60 through pipes 48a in central conduit 47. Also located above baffle 84 is hole 88 which is the entrance through which water exits the sand helix 48 and enters pipe 88a contained inside of central conduit 68. The water entering through holes 88 is conveyed through pipe 88a to an oil helix 52, or discharged to the sea through the water works executive 62 shown in FIG. 4 via valve 88h, pipe 88b, valve 88c, pipe 88d, hydrocyclone 120a, flushing vessel 120c, pipe 120d, valve 120f, and discharge pipe 120g, or through valve 88h, pipe 88e, valve 88f and pipe 88g through the open end 90 of separator 20.
Thus, in operation, the sand helix module 48 receives a flow of water downwardly in casing 58 in the direction indicated by the arrows 92. Water flows between the inside wall of casing 58 and around the bottom of shell 64 and upwardly through vanes 74. The vanes 74, due to their helical shape, swirl the waste water mixture gently upward, creating laminar flow. Based on Stoke's Law, sand particles flow counter currently to the oil and water stream and fall downwardly through the sand helix.
Sand falls downwardly due to its higher density (relative to water) on the upper face of the vanes and out of the bottom of the helix as indicated by the arrows 94. Oil will rise upwardly due to its lower density (relative to water) and the small droplets of oil will strike the underside of the vanes of the sand helices, adhere, and travel upwardly along the underside of the vanes of the sand helices. Oleophyllic (oil wettable) materials (Polypropylene and the like) can be used for the vane material to enhance the efficiency of the Stoke's Law law effect, which assumes that oil particles adhere to, and coalesce when they strike a surface. Droplets may coalesce in suspension and/or while traveling up the vanes. The oil traveling up the vanes is forced up and toward the center of the helix as indicated by the arrows 96 and upwardly into hole 86. Baffle 84 serves to guide the center column of oil into hole 86. Water is forced up and outward between the vanes and travels upwardly as indicated by arrows 98 down pipe 88a through hole 88. Thus, the helically shaped vanes, in addition to Stoke's Law separation, centrifugally force the water and sand to the outside and the oil to the inside, effecting a separation thereof in a favorable manner. Sand falling from the bottom of the module is collected in sand manager 50.
Located beneath the sand helix module 48 is the sand manager module generally indicated by the numeral 50 in FIGS. 1, 5, and 6. The sand manager 50 has a central conduit 100 in the center thereof which is a continuation of central conduits 47 and 68 and is connected by flange 102 to sand helix module 48 thereabove. Central conduit 100 is similar to central conduit 68 (see FIGS. 7 and 8) and is aligned and flanged thereto. Central conduit 100 receives and contains the various conduits 270, 256, 120 and 88a for transmitting fluids and particles from one component or stage of the separator 20 to another.
Rigidly connected to central conduit 100 is a cone shaped partition 103 which has a horizontal ring 104 internally formed therewith. The combination of the cone shaped partition 103 and ring 104 forms a reservoir 106 for receipt of the recovered sand slurry, indicated by the horizontal broken lines therein.
If the sand contained in the reservoir 106 contains oil, the water jet eductors generally indicated by the numeral 108 may be utilized to thoroughly scour the oil from the oil-covered sand. Water jet eductors 108 are known in the art and contain a high pressure water pipe 110 which sprays water and/or steam into a venturi (hour glass) shaped surface 112. In the separator of the present invention, water, rather than steam will be used. Water under high pressure is forced through the venturi 112 as indicated by the arrow 114. The high pressure water traveling through the eductors 108 forces sand and recirculated water to travel through the eductors and to be highly agitated with the water flowing in through pipe 110. The agitation and turbulence created within the reservoir 106 causes the oil clinging to the sand to be washed or stipped from the sand. The oil stripped from the sand floats up the structure and into the sand helices 48. As the level of water and oil reaches the sand helices, the water and oil are drawn through the sand helices.
Clean sand collected in sand manager 50 is withdrawn through drain pipe 116 by opening control valve 118 (see FIG. 4) and discharged overboard into the sea. Alternatively, a slurry of water and oily sand can be withdrawn through pipe 120 continously when a large amount of sand is being separated. After being scoured by the eductors 108, oil covered sand is removed through pipe 120, and the slurry flows into a hydrocyclone 120a in the water works executive 62 shown in FIG. 4. Water and oil flow upwardly through pipe 120b and valve 120h and sand flows into vessel 120c. Sand can be removed through pipe 120d and water can be introduced through pipe 120e for flushing vessel 120c.
Located between the sand manager and the lower oil manager in a air space with flanged headers on either side, is the water works executive 62. It is an area which houses the controls, valves, meters and the like to control the oil, water and sand flow between the various components. It is the entrance locale for the waste water stream 46, additional gas make up stream 41, high pressure water stream 110, fresh water stream 120e, and an exit point for the oil stream 282. Also, gas can be added or removed through pipe 257. The valves for controlling the oil and water levels by use of gas from the waste water stream 46 or from additional feed gas are maintained therein. The valves can be controlled by hand or electrically or pneumatically. The hydrocyclone 120a and reservoir 120c can also be located within.
Located beneath the water works executive 62 and sand manager 50 is the lower oil manager 54 shown in FIG. 1 and FIG. 10. The lower oil manager receives oil from the upper oil manager 60 through pipes 256 and lower stages or components through pipes 280. Lower oil manager 54 is contained in cylindrical enclosure 58 which is closed at the upper end by flange 58a.
Lower oil manager 54 has outwardly tapered bottom walls 54a connected to vertical intermediate walls 54b and to central conduit 47. Walls 54b are connected to inwardly sloped upper walls 54c. A vertical wall 54d is connected to the top of wall 54c. The walls 54a-54d form a reservoir for holding oil indicated by the horizontal broken lines therein. As can be seen in FIG. 10, gas in the top of the lower oil manager 54 can be removed or added through pipe 257 and valve 257a to control the level of the oil pad 310. Oil contained in oil manager 54 is pumped through pipe 282 by pump 284 to a storage tank 49 on the surface 32 of the platform 22.
Located beneath lower oil manager 54 is an oil reservoir generally indicated by the numeral 300 having a series of holes 306 therein. Here oil, having risen through pipe 304 from oil helices 52 (see FIGS. 2, 3 & 10), accumulates as a thick oil pad 310 between central conduit 47 and outer casing 58 which floats on the water 400 in casing 58. Positive pressure is maintained in this whole lower half of separator 20 because of the continuous addition of gas through pipe 40 to lift oil from the oil pad 310 to the lower oil manager 54, and by venting any excess through pipe 257.
Thus, the oil "pad" or reservoir is maintained at a level equal to or slightly lower than minimum sea level. To circumvent the typical problems incurred with "blowcases" or submerged pumps, pipe 306a connected to hole 306b take suction at the oil pad and physically traverses downward through the central conduit 47 for a calculated distance, elbows upward for 180 degrees into pipe 280, and rises in pipe 280 all the way up central conduit 47 past the suction level to the lower oil manager 54 (see FIGS. 3 & 10). Gas line 40 also runs down the conduit 47 and ties in the upflow side, slightly above the lowest point, of the pipe 280, and utilizes what is known in the art as "gas lift" to raise the oil into the reservoir of the lowest oil manager.
Located beneath the oil pad 310 is the oil helix module generally indicated by the numeral 52 (see FIGS. 2 & 3). The oil helix receives waste water from the sand helix through pipe 88a. The oil helix module 52 is identical in design and construction to the sand helix previously described and shown in FIGS. 7 and 8 with the exception that the piping inside of the central conduit indicated by the numeral 168 in FIG. 2 and 68 in FIG. 7 includes pipes 40, 88a, 88g, 120g, 280, 304 and 306a. The oil helix 52 contained within casing 58 includes an outer shell 164 which is generally cylindrical in shape. The bottom of the outer shell 164 is open and the top 166 is shaped like a truncated cone. Located in the center of shell 164 is central conduit 168 which contains a series of smaller pipes 40, 88a, 88g, 120g, 280, 304, and 306a for transferring fluids between the various components and stages of separator 20. Flanges 172--172 are located at the top and the bottom of the oil helix module 52 for attaching a series of modules together or for attaching different modules above and below. The top 166 is rigidly secured to pipe 168 to prevent any fluids from escaping upwardly between top 166 central conduit 168.
Located between central conduit 168 and shell 164 are a series of helical vanes 174 held in place by a series of concentric horizontal rings 176. The rings are in turn supported by a series of concentric cylinders 178 to which the horizontal concentric rings 176 are rigidly attached. The inner-most concentric ring 180 is rigidly connected to central conduit 168.
The helical vanes 174 have a bottom edge 182 and a top edge (not shown) which are generally in alignment with the top and bottom ends of outer shell 164. In the embodiment shown in FIGS. 2 and 3 the helical vanes 174 are contained in three chambers formed by the two concentric cylinders 178. The number of chambers and number of vanes may be varied as desired. The length of the vanes can be varied as desired to achieve the desired flow pattern.
In lieu of vanes, helical tubular pipes (not shown) can be similarly aligned similarly to vanes 174 and held in place by a series of concentric horizontal rings 176 (or other suitable means), generally aligned with top and bottom end of outer shell 164.
Connected to the upper end of central conduit 168 and beneath the conical top 166 is a baffle 184. Beneath baffle 184 is a hole 186 for the intake of oil separated and coalesced from the oil and water slurry which enters the oil and helix through the hole 185.
The oil separated from the oil and water stream exits the oil helix 52 and enters pipe 304 contained inside of the central conduit 168 through holes 186 and is conveyed upwardly to the oil pad 310 (see FIG. 10). Hole 185 is located above the baffle 184 and is the entrance, by pipe 88a, through which the oil and water stream enters the oil helix as indicated by the arrow 185a. The oil and water mixture travels over the baffle as indicated by the arrow 185a and encounters the helical vanes 174.
Thus, in operation, the oil helix modules 52 are surrounded by a flow of water downwardly discharged from above the module 52 in casing 58 in the direction indicated by the arrows 192 thus maintaining water throughout the casing and at the bottom of shell 164. The flow of water downwardly from above the module 52 comes either from optional deck drain flow lines (not shown) on platform 32 entering casing 58 immediately below the oil pad 310 or from the oil helix modules 52 located above lower oil helix modules 52. If there is only one oil helix module 52 and no deck drains, there would be no flow down around the top oil helix. If a plurality of oil helices 52 are used, there would be no flow down around the top oil helix if there were no deck drain connections. Water entering the oil helix 52 through entrance 185 encounters the vanes 174 and swirls gently downward, remaining in the Reynold's laminar flow regime. Based on Stoke's Law, oil particles flow counter currently to the water stream and rise upwardly through the oil helix. Oil will rise upwardly due to its lower density (relative to water) and the small droplets of oil will strike the underside of the vanes of the oil helices 52, adhere, and travel upwardly along the underside of the vanes of the oil helices 52 into hole 186 as indicated by the arrows 186b. The water continues to travel downwardly and joins the stream 192 after its exit from the bottom of the module. Thus the helical shaped vanes, in addition to Stoke's Law separation, centrifugally force the water to the outside of shell 164 and the oil to the inside of the shell, effecting the separation of the oil-water stream in a favorable manner.
The amount of sand helix modules 48 and oil helix modules 52 may be varied to achieve the degree of separation desired. One, two, three or more of the sand helix modules 48 or oil helix modules 52 may be utilized. Preferably, three sand helix modules 48 and three oil helix modules 52 are used.
Both the sand helix (or helices) 48 and the oil helix (or helices) 52 must have means for causing fluids to flow therethrough in a spiral or swirling manner to separate oil and sand from water, such means having a surface to which small droplets will adhere and travel upwardly. The means for causing fluids to flow in a spiral or swirling manner can be hollow pipes or vanes 74 and 174 arranged in the helix in a spiral configuration. The vanes or pipes are parallel when viewed from a vertical cross-section and vertical when viewed through a horizontal cross section.
It should be understood that the apparatus of the invention could be used on onshore rigs, offshore rigs, or to treat any waste water stream containing water oil, and/or sand. Furthermore, the term "oil" can include any two fluids that form two phases. To utilize the apparatus of the invention onshore, it would only be necessary to enclose the bottom and attach a valve, pipes, and a pressure control mechanism to maintain water and oil levels. Also, a different configuration such as two columns separated at the water works executive 62 with different valve settings to maintain a similar operating environment can be used.
Although the preferred embodiments of the present invention have been disclosed and described in detail above, it should be understood that the invention is in no sense limited thereby, and its scope is to be determined by that of the following claims. | A method and apparatus for separating oil, gas, and sand from a waste water stream and for separating oil from oily sand in a waste water stream including an upper oil manager for removing low pressure gas and at the same time collecting and conveying any oil separated from the waste water stream; a sand helix connected to the upper oil manager for separating sand particles and oil particles from the waste water stream; a sand manager connected to the sand helix for collecting sand separated from the stream of waste water and removing oil from the sand; flow controls connected to the sand manager and the lower oil manager for controlling the flow of oil, water and sand through the apparatus; a lower oil manager connected to the flow controls for receiving oil and transferring oil to a storage tank outside of the apparatus; an oil reservoir located beneath the lower oil manager for receiving and containing oil, and an oil helix connected to the lower oil manager for separating trace oil from the waste water stream. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional patent application No. 60/846,165 filed Sep. 20, 2006, the disclosure of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The field of the present invention is semiconductor device fabrication and device structure. More specifically, the present invention relates to the alignment and application of color filters to back illuminated imagers.
BACKGROUND OF THE INVENTION
[0003] CMOS or CCD image sensors are of interest in a wide variety of sensing and imaging applications in a wide range of fields including consumer, commercial, industrial, and space electronics. CCDs are employed either in front or back illuminated configurations. Front illuminated CCD imagers are more cost effective to manufacture than back illuminated CCD imagers such that front illuminated devices dominate the consumer imaging market. Front-illuminated imagers, however, have significant performance limitations such as low fill factor/low sensitivity (the active region of a pixel is typically very small (low fill factor)). As a result, there is a significant amount of interest in the development of color back illuminated imagers. Color back illuminated imagers contain an array of color filter elements sensitive to a plurality of different colors of light, such as the primary colors red, green, and blue. The filter elements can be arranged in a variety of patterns, the most commonly used being the Bayer pattern to be discussed hereinbelow in connection with the present invention.
[0004] In order to maintain color purity, each filter element needs to be precisely aligned, i.e., registered, to a corresponding pixel (at least the light sensitive portion of a pixel). In a traditional front-illuminated imager, color filter elements are applied in set of three steps using conventional photolithography and alignment tools similar to those used to create the imager itself. One common method for obtaining a registered pattern uses colored photoresists. In the photoresist process, a wafer containing a plurality of front-illuminated imagers is coated with a material (photoresist) that is sensitive to ultraviolet (UV) light. On exposure to light, the photoresist is rendered insoluble in particular solvents (developers). FIGS. 1A-1D show the process of producing color back illuminated imagers using photoresists of different colors to produce a desired filter pattern. FIG. 1A shows a portion of an array 10 of pixels 12 of a front illuminated imager before the application of photoresist. FIG. 1B shows a layer 14 of blue photoresist being applied to the entire array 10 . A subset of the pixels 12 is illuminated with a pattern of UV light to which the layer 14 is sensitive. In FIG. 1C , solvents are applied to the blue photoresist such that those portions 16 exposed to UV light become insoluable and therefore remain on the wafer while other areas 17 are dissolved away. In FIG. 1D , the process is repeated for photoresists of the other colors (green and red), which results in the device shown. Note, the filter material (insoluable photoresist) need only cover the actual photo sensitive portion of a pixel. In front illuminated imagers, especially those with small pixels, a relatively large portion of the pixel is devoted to signal and control electrodes.
[0005] For back illuminated imagers, the entire area of a pixel can be used for light gathering. As a result, the entire area of the pixel can be covered with the filter material. The back side of the back-illuminated imager, therefore, can provide a single flat surface that can accept an integrated filter, i.e. a filter containing three sets of primary color filter elements aligned in pattern to match the light sensitive portions of the pixels in the imaging array. FIG. 2 show an example of a color back illuminated imager 18 having an integrated color filter array 20 positioned on a back side 22 of the imager 18 as is known in the prior art. The back illuminated imager 18 includes an array of pixels 24 each having a light sensitive region 26 located on the front side 28 of the imager 18 . The back side 22 of the imager 18 is completely covered by a plurality of filter elements 30 of one or more colors arranged in a patterns such as the Bayer pattern discussed above.
[0006] If the integrated filter 20 is produced by semiconductor manufacturing processes similar to those used for front-illuminated imager color filters, the resulting color back illuminated imager 18 may have poor registration of the color filter elements 30 to the to the light sensitive regions 26 of the pixels 24 . Poor registration may result because the pixels 24 on the front side 28 of the imager 18 are not directly visible to manufacturing equipment used to locate the positions of the color filter elements 30 on the back side 22 .
[0007] The alignment of a color filter pattern on the back side 22 of the back illuminated imager 18 in two dimensions now becomes very important, since any shift of the pattern will result in degradation of color fidelity. Further, because such a back-illuminated color filter 20 would be constructed on the back side 24 of the imager 18 using photoresists and employing photolithography, the manufacturing of the integrated filter 20 is subject to the same solvent and etching material limitations as is found with front-illuminated imager color filters. Also, because the application of photoresists is repeated three times—one for each color—the likelihood of defects in one or more of the colors is greatly increased. Defects in a color filter pattern produces an imager 18 that does not function properly, even though the underlying imager functions properly electrically. The production of defect-free color mask patterns on the back side 22 of the imager 18 is made even more difficult when the thickness of the semiconductor material is 4 to 10 μm or less, leading to warpage and other distortions of the light sensitive regions 26 of the pixels 24 .
[0008] Accordingly, what would be desirable, but has not yet been provided, is a method for aligning and affixing a monolithic integrated color filter array to the back side of a back-illuminated imager in which the manufacturing process of the color filter array is independent of the manufacturing process of the imager.
SUMMARY OF THE INVENTION
[0009] Disclosed is an apparatus and method for registering a color filter array to a back illuminated imager, comprising the steps of providing at least one color filter array comprising filter elements of at least a first color and a second color; providing at least one back illuminated imager having a front side and a back side and comprising a plurality of pixels proximal to the front side, a first portion of the plurality of pixels being associated with the first color, and a second portion of the plurality of pixels being associated with the second color; illuminating the at least one color filter array and the back side of the back illuminated imager with monochromatic light having a wavelength corresponding to the first color; rotating and translating the at least one color filter array relative to the back illuminated imager; measuring a first response of at least one pixel associated with the second color; and repeating the rotating, translating, and measurement steps until the response is a minimum. The color filter array can also comprise elements of a third color, wherein a third response of at least one pixel associated with the third color is measured repeatedly while rotating and translating the color filter array relative to the back illuminated imager until the response for both colors that do not correspond to the illuminating source are minimized. This process can be repeated by substituting light of second color and then a third color for the illuminating source and then finding a best fit translation and rotation vector based on the three sets of measurements. The aligned back illuminated imager can then be adhered to the color filter array by means of an adhesive.
[0010] A device can be constructed from the at least one back illuminated imager and the at least one color filter array, comprising a transparent substrate; at least one color filter array comprising a plurality of filter elements of at least a first color and a second color substantially overlying said transparent substrate; an adhesive layer substantially overlying the at least one color filter array; and at least one back illuminated imager having a front side and a back side and comprising a plurality of pixels proximal to the front side, a first portion of the plurality of pixels being associated with the first color, and a second portion of the plurality of pixels being associated with the second color, wherein the at least one back illuminated imager is oriented to the at least one color filter array based on rotating and translating the at least one color filter array relative to the at least one back illuminated imager so as to minimize a response of at least one pixel associated with the second color to illuminated with monochromatic light corresponding to the first color. The at least one back illuminated imager can be a charge coupled device (CCD), a CMOS based back illuminated imager, or a plurality of back illuminated imagers arranged on a wafer. The elements of the at least one color filter array can be arranged in a Bayer pattern comprising three primary colors. The filter elements of the at least one color filter array can be made with organic dyes. Alternatively, the filter elements can include multiple thin layers of inorganic materials acting as interference filters.
SUMMARY DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A is a schematic diagram of a portion of an array pixels of a front illuminated imager before the application of photoresist;
[0012] FIG. 1B is a schematic diagram showing a layer of blue photoresist being applied to the entire array of FIG. 1 ;
[0013] FIG. 1C is a schematic diagram showing solvents being applied to the blue photoresist such that those portions exposed to UV light become insoluable and therefore remain on the wafer while other areas are dissolved away;
[0014] FIG. 1D is a schematic diagram of a color front illuminated imager in the prior art after photoresists of multiple colors are applied and patterned;
[0015] FIG. 2 is a schematic diagram showing a color back illuminated imager in the prior art having an integrated color filter array positioned on a back side of the imager;
[0016] FIG. 3 is a schematic diagram depicting a monolithic color filter array constructed in accordance with an embodiment of the present invention;
[0017] FIG. 4 is a schematic block diagram showing equipment for aligning and affixing the monolithic color filter array of FIG. 3 to a back illuminated imager according to an embodiment of the present invention; and
[0018] FIG. 5 depicts a monolithic color filter array having the configuration of a Bayer pattern which can be used in conjunction with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The following embodiments are intended as exemplary, and not limiting. In keeping with common practice, figures are not necessarily drawn to scale.
[0020] FIG. 3 depicts a monolithic color filter array 32 constructed in accordance with an embodiment of the present invention. FIG. 4 shows a back illuminated imager 34 to which the monolithic color filter array 32 is to be aligned and affixed using test equipment 36 . The manufacture of the color filter array 32 is performed in a separate series of operations. The color filter array 32 includes a transparent substrate 38 . The transparent substrate 38 can be made from a variety of suitable materials, such as glass or quartz. The composition of the substrate 38 should be mechanically compatible with the semi-conductor material of the back illuminated imager 34 . It should also be stable over temperature and time. A plurality of color filter elements 40 of at least one color, preferably three primary colors, (e.g., red-blue-green or magneta-cyan-yellow), and incorporated into the monolithic color filter array 32 substantially overly the transparent substrate 38 . Each of the plurality of color filter elements 40 is sized and shaped to substantially underlay at least the light-sensitive regions 42 of a pixel elements 44 of the back illuminated imager 34 . FIG. 3 also shows an adhesive layer 46 substantially overlying the plurality of color filter elements 40 . The adhesive layer 46 is provided so that the monolithic color filter array 32 may be adhered to the back surface 48 of the back illuminated imager 34 . This allows for the plurality of color filter elements 32 and the back surface 48 of the back illuminated imager 34 to be in near intimate contact during the alignment process, separated only by a thin liquid layer (the adhesive layer 46 ). This prevents light incident on the color filter elements 40 from spreading beyond the boundaries of the light-sensitive regions 42 of pixel elements 44 , which would result in optical losses and reduce sensitivity.
[0021] Because the color filter array 32 is built separately from the back-illuminated imager 34 , the materials for the color filter elements 40 can be freely chosen without being subject to limitations in processing conditions which may contaminate or destroy the pixel elements 44 in the imager 34 . Producing the monolithic color filter array 32 would not require any compromises to be made in chemicals used, filter materials, process temperature, application methods or other conditions that are imposed if the color filter elements 40 were to be created on an already processed imager array. Further, the entire array of color filter elements 40 can be fully inspected for defects. Separating the manufacture of the color filter array 32 from the manufacture of the imager 34 allows for greater efficiency and higher yield in both the imager 34 and the monolithic color filter array 32 . Furthermore, the color filter array production process can be separately optimized for pattern fidelity. The monolithic color filter array 32 can be independently inspected for conformance to size and placement of each of the color filter elements 40 . Filter arrays that do not meet quality standards can be rejected without having to reject an entire back-illuminated imager, as would be the case for an imager that has integrally manufactured color filter elements.
[0022] Referring now to FIG. 4 , in a preferred embodiment, a first fixture 52 holds the back illuminated imager 34 having a back surface 48 and a front surface 50 , the front surface 50 being the location for a plurality of light sensitive pixel elements 44 that can be aligned relative to the at least one color filter array 32 held by a second fixture 54 . The imager 34 can be a partially packaged device that is inserted into the first fixture 52 . This is a preferred embodiment since all of the electrical connections to the imager 34 are already established and tested and the package will contain an opening to allow light to fall on the imager 34 . Alternatively, several imagers can be located on a surface of a wafer whose output electrodes are connected to the test equipment 36 by means of a probe card (not shown). Ideally the imagers on the wafer are located at positions close to the edge of the wafer. Likewise the at least one color filter array 32 can be a plurality of color filter arrays to be aligned with the plurality of imagers on the wafer. Individual defect-free color filter arrays can be selected.
[0023] The imager(s) 34 is/are situated such that the back surface(s) 48 can be illuminated using monochromatic light. At least one light source 56 of at least one wavelength is designed to illuminate the color filter array 32 . In some embodiments, the at least one light source 56 can be an array of light sources of the three primary colors described above, corresponding to three primary colors used in the monolithic color filter array 32 . The at least one light source 56 can be one or more red, green and blue light emitting diodes (LEDs) arranged as an LED array 56 . The LED array 56 is constructed such that the diodes of a single color may be selected by the test equipment 36 . Further, the intensity of the illumination from each color can be varied under control of the test equipment 36 . The LED array 56 can be designed to provide uniform, collimated light over the area of a single imager 34 . The illumination source 56 for use with large diameter wafers can comprise multiple LED arrays disposed in the approximate positions of the imagers under test.
[0024] The color filter elements 40 of independently fabricated monolithic color filter arrays 32 can be precisely registered with the light-sensitive regions 42 of a pixel elements 44 in the imager 34 . Registration is performed by observing the electrical signals emanating from the imager 34 . The color filter array 32 to be aligned is interposed between at least one light source 56 and the imager 34 . The color filter array 32 can be translated and rotated with respect to the back surface 48 of the imager. Alternatively, the color filter array 32 can be held stationary and the imager 34 rotated and translated. The color filter array 32 or the imager 34 can be moved such that controlled contact can be established between the back surface 48 of the imager 34 and the adhesive layer 46 . The test equipment 36 controls all motions of the color filter array 32 and imager 34 with respect to each other.
[0025] An imager output block 58 includes equipment for collecting the analog voltage signals 60 representing the output signals of the plurality of light sensitive pixel elements 44 and may contain equipment, such as data acquisition modules or a microcontroller containing one or more analog-to-digital converters for converting these analog voltage signals 60 to digital signals 62 . A test and analysis block 64 contains at least one processor 66 and memory 68 for receiving and processing the digital signals 62 . The at least one processor 66 operates on a program stored in the memory 68 for determining the light output of the plurality of pixel elements 44 , and for determining a set of control signals to be applied to one or both of the fixtures 52 , 54 for adjusting the relative position of the imager 34 with the color filter array 32 . The second fixture 54 can be configured to be movable relative to the first fixture 54 according to three degrees of freedom of translation and three degrees of freedom of rotation.
[0026] In operation, the color filter array 32 is moved to near intimate contact with the back surface 48 of the imager 34 . The imager 34 is illuminated with light of a single wavelength by the at least one light source 56 corresponding to a color associated with one type of the color filter elements 40 . The analog voltages 60 produced by the plurality of pixel elements 44 is measured and converted to digital signals 62 by the imager output block 58 , which in turn sends the plurality of digital signals 62 to the at least one processor 66 in the test and analysis block 64 . The at least one processor 66 then signals one or both of the fixtures 52 , 54 to rotate and/or translate its position so as to minimize the measured response (output voltages) from the subset of the pixel elements 44 that do not correspond to the color (wavelength) selected for illumination. Optimizing for a minimum response from the subset of pixel elements associated with the subset of color filter elements that do not correspond to the selected wavelength (color) of illumination also has the effect of maximizing the response of the subset of pixel elements associated with the color filter elements that do correspond to the selected color of illumination. Optionally, the response of the selected color of illumination can also be measured.
[0027] In some embodiments, rotation can be optimized first, wherein the at least one light source 56 comprises two LEDs of the same color widely separated for use with pixel elements disposed at extreme positions on a semiconductor wafer. It may be necessary to use at least two LEDs because it may be difficult construct a single LED light source to illuminate a semiconductor wafer that is 8-12″ in diameter. Illuminating pixels that are far apart with a single LED can exaggerate small errors in rotation. Once optimized for rotation, all of the color filter elements 40 are parallel to the pixel elements 44 and have the same center of rotation. Then, translation can be optimized using one of the two LEDs above. If response is optimized for rotation first before translation, then the adjustment for translation is simplified because all of the signal responses from the pixel elements 44 change in the same way uniformly. A person skilled in the art would appreciate that other optimization algorithms could be used, wherein translation optimization can be performed before rotation optimization, or a combination of both could be employed simultaneously.
[0028] In a preferred embodiment, the at least one light source 56 can comprise a plurality of arrays of LEDs of three primary colors so as to minimize errors caused by spread of an applied beam of light. Spreading of the light beam can also be minimized when the color filter array 32 and the imager 34 are in near intimate contact. For increased accuracy, the process outlined above can be carried out sequentially using red, then blue, and then green LEDs. By recording the relative positions of the color filter array 32 and the imager 34 using each of the three colors, a ‘best fit’ set of translation and rotation vectors can be determined. Once the optimized position and orientation of the color filter array 32 is determined, the color filter array 32 can be directly affixed to the rear surface 48 of the imager 34 using a suitable adhesive.
[0029] In a preferred embodiment, the alignment technique of the present invention can be used in conjunction with a monolithic filter array having the Bayer pattern previously discussed. The Bayer pattern is depicted in FIG. 5 . A Bayer pattern can have RGB pixels in the ratio 1:2:1 organized as shown. In a filter array 68 constructed with colors distributed according to a Bayer pattern, there are twice as many green filter elements 70 as there are of blue 72 or red 74 filter elements. This results in greater proximity of green filter elements 70 to each other compared to the blue 72 or red 74 filter elements. Using the filter array 68 having a color distribution according to a Bayer pattern in which green is represented twice as often as red or blue is a suitable configuration of pixel color distribution because the human eye is more sensitive to green. If the Bayer pattern array 68 is illuminated with red or blue light, ideally one fourth of the pixels can have identical outputs and three-fourths will have no output. A down side to using such a pattern is that the arrangement of green filter elements 70 is symmetrical, so that that amount of movement away from one green pixel can be cancelled by the simultaneous movement by the same amount toward another green pixel, with the result that another green filter element is associated with the same pixel, thereby making it more difficult to achieve proper alignment. In such circumstances, it is best to first align on either red 74 or blue 72 filter elements, which are asymmetrical in a Bayer filter pattern, so that moving away from either a red 74 or blue 72 filter element has a lower probability of moving into an area of the Bayer array associated with another red or blue filter element. Thus, in an embodiment employing a color filter array 68 having a Bayer pattern, it would be preferable to illuminate the filter array with either red or blue light, say, for example, red light, and then adjust the relative position of the filter array 68 and/or the imager to minimize the signal to be detected in green and blue. Best results can be obtained if all of the data from the imaging array 68 is used. In a two megapixel array, for example, there are 1,000,000 green pixels and 500,000 blue and green pixels, respectively. Using blue illumination, for example, the best alignment position can be found by simultaneously minimizing the signals in the 1,500,000 other pixels. The large degree of data redundancy ensures that the best solution can be found.
[0030] The present invention is subject to modifications. For example, although the present invention is independent of the type of color filter array used, filter elements of a monolithic color filter array can be made with organic dyes. The color filter elements can include multiple thin layers of inorganic materials acting as interference filters, such as dichroic filters.
[0031] It is to be understood that the exemplary embodiments are merely illustrative of the invention and that many variations of the above-described embodiments may be devised by one skilled in the art without departing from the scope of the invention. It is therefore intended that all such variations be included within the scope of the following claims and their equivalents. | A method for registering a color filter array to a back illuminated imager is disclosed, comprising the steps of providing at least one color filter array comprising filter elements of at least a first color and a second color; providing at least one back illuminated imager having a front side and a back side and comprising a plurality of pixels proximal to the front side, a first portion of the plurality of pixels being associated with the first color, and a second portion of the plurality of pixels being associated with the second color; illuminating the at least one color filter array and the back side of the back illuminated imager with monochromatic light having a wavelength corresponding to the first color; rotating and translating the at least one color filter array relative to the back illuminated imager; measuring a first response of at least one pixel associated with the second color; and repeating the rotating, translating, and measurement steps until the response is a minimum. The aligned back illuminated imager can then be adhered to the color filter array by means of an adhesive. | 6 |
BACKGROUND OF THE INVENTION
The present invention relates generally to electrical microcircuit structures with silicon nitride passivation, and more particularly to improved structures that allow included thin-film components to be laser trimmed without damaging the passivation coating.
In the manufacture of thin-film and monolithic hybrid microcircuits, passive circuit elements such as resistors and capacitors are prepared from films of materials only a few thousand angstroms thick. The films usually are deposited by vacuum evaporation or sputtering, with the necessary patterning being accomplished before, during, or after deposition. As a final step before packaging, a protective overcoating or passivation film may be applied to the circuit. A good passivation coating is especially necessary if the microcircuit will not be sealed in a hermetic enclosure. Silicon nitride (Si 3 N 4 ) is used extensively as a passivation material because of its high resistivity and dielectric strength, excellent chemical resistance, and superior electrical and thermal stability.
Even with well-controlled processes, the values of initially fabricated thin-film components typically fall within a 5-15% tolerence range. More accurate values are achieved by physically removing portions of the components in a subsequent trimming operation. Airborne abrasive, electric arc, and laser beam trimming systems have been developed for this purpose. Laser trimming systems have a number of significant advantages, including greater speed, accuracy, and cleanliness. In addition, they can be used under computer control to adjust circuit components while their values are being measured.
Components may be laser trimmed after the passivation film is applied if a laser operating in the visible or near infrared region is used. By so doing, a completed circuit can be adjusted for optimum operation during active, functional testing.
In the past it has not been possible to trim certain thin-film components in silicon nitride-passivated circuits without damaging the nitride layer. For example, during trimming of Nichrome and other nickel- or chromium-containing films, voids and cracks in the passivation layer are produced, forming an entry point for contaminants.
Because of the superior protection provided by silicon nitride, there is a need to provide a way to laser trim thin-film components containing nickel, chromium, or other metals in hybrid circuits that incude a Si 3 N 4 passivation layer.
SUMMARY OF THE INVENTION
According to the present invention, the above-expressed need has been satisfied by the discovery that a contiguous oxygen-containing film formed over thin-film components containing nickel, chromium, or other metal allows laser trimming of the components through an overlying silicon nitride passivation layer without damaging it. Suitable film materials include the stable oxides of aluminum, silicon, tantalum, titanium, and zirconium.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary sectional view of a prior art microcircuit including a thin-film resistor that has been laser trimmed through an overlying silicon nitride passivation layer;
FIG. 2 is a fragmentary plan view of a laser-trimmed thin-film microcircuit structure according to the present invention; and
FIG. 3 is a sectional view taken along view line 3--3 in FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
Turning now to the drawings, the problem solved by the present invention is illustrated in FIG. 1. A thin-film resistance element 2 on a substrate 4 has been laser trimmed along one edge 3 through an overlying silicon nitride passivation layer 6. The trimming operation has produced a void 8 at the trimmed edge of the resistance element, and a crack 10 that extends from the void to the outer surface of the nitride passivation layer. Fractures in the passivation provide an entry point for moisture and contamination, which adversely affect circuit reliability and performance. Such fractures are particularly detrimental if the passivation layer is the sole form of environmental protection for the circuit, i.e., where it is not packaged in a separate hermetic enclosure.
It is believed that such voids and cracking result from the formation of unstable metal nitrides, nickel and chromium nitrides for example, during laser trimming. Such nitrides are created by reactions between a component's constituents and the Si 3 N 4 passivation layer as the laser beam vaporizes portions of the thin-film components. The nitrides dissociate at the high localized temperatures produced by the trimming operation, forming nitrogen gas that expands and fractures the passivation layer.
An improved microcircuit structure free from the just-described problem is shown in FIGS. 2 and 3. Referring first to FIG. 2, a hybrid circuit 20 supported on an insulative substrate 22 of glass, alumina, silicon oxide, or the like includes a thin-film resistor 24. The resistor comprises a pair of electrical terminals 26, 28 overlapping the opposite ends of an elongate resistive film element 30. Element 30 is deposited on substrate 22 by vacuum evaporation or sputtering of a suitable resistance material, such as chromium, a nickel-chromium alloy (Nichrome), an alloy of chromium and silicon (e.g., CrSi 2 ), or a cermet composed of chromium and silicon oxide. Terminals 26, 28 are of a similarly-deposited conductive metal, usually gold or aluminum.
Overlying resistor 24 is a passivation coating formed by an oxide underlayer 32 and an outer layer 34 of silicon nitride. The oxide underlayer functions to prevent the formation of metal nitrides during laser trimming, and may be any oxide film with the required electrical properties that can be made to adhere satisfactorily to the circuit substrate and components. Suitable materials include aluminum oxide (Al 2 O 3 ), tantalum oxide (Ta 2 O 5 ), titanium dioxide (TiO 2 ), silicon oxides (SiO, SiO 2 ) and zirconium oxide (ZrO). Silicon oxides are particularly preferred.
Referring to FIG. 3 along with FIG. 2, metal constituents of resistive element 30 react with passivation underlayer 32 during laser trimming to form stable metal oxides rather than unstable nitrides. These oxides diffuse out into adjacent portions of the substrate and oxide underlayer to form a zone 36 of comparatively high resistivity adjoining trimmed edge 31 of thin-film element 30.
The passivation coating layers are applied by any suitable process, such as chemical vapor deposition. The underlayer must be thick enough to prevent fracturing of the passivation coating during laser trimming, and its thickness will depend on the thickness of the material being trimmed. By way of example, resistors formed by the deposition of a 50 ohms per square, 400 angstrom thick Nichrome thin-film have been trimmed satisfactory through a passivation coating consisting of a 2,000 angstrom glassy silicon oxide underlayer and an outer layer of Si 3 N 4 having a thickness of about 8000 angstroms. As will be understood, the silicon nitride is applied in a thickness sufficient to provide the desired environmental protection, and typically is in the range of about 7,000 to 12,000 angstroms. The oxide layer preferably has a minimum average thickness of about 1000 angstroms.
While the best mode presently contemplated for practicing the invention has been set forth, it will be appreciated that various changes and modifications are possible in addition to those specifically mentioned. The appended claims are thus intended to cover all such variations and modifications as come within the scope of the invention. | Microcircuit structures including thin-film electrical components are provided with a multilayer passivation coating that permits laser trimming of the components through the coating without damaging it. Such a passivation coating suitably includes an underlayer of silicon oxide or other oxygen-containing material and an outer layer of silicon nitride. | 8 |
This application is the U.S. National Phase of, and Applicant claims priority from, International Patent Application Number PCT/NL2009/050782 filed 18 Dec. 2009 and European Patent Application Number 08075951.7 filed 18 Dec. 2008, each of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The invention relates to the field of papermaking. More in particular, the invention relates to the use of a novel dry strength agent in the wet-end of the papermaking process.
Traditionally, cationic starches are applied as dry strength agents in the wet-end of the paper production process. Due to the presence of anionic groups on the cellulose fibres and fillers, cationic starch binds to the fibres and fillers. This electrostatic interaction also gives an improvement in the retention on the sieve of both the cellulose fibres and the fillers in the paper sheet. Beside as dry strength agent and retention support cationic wet-end starches are also used for alkenyl succinic anhydride (ASA) emulsification in the wet-end.
A serious drawback of the use of cationic starch is its limitation of the amount of cationic starch that can be used. Addition of cationic starch to the fibres gives rise to the neutralisation of the anionic charge on the cellulose fibres and fillers and eventually overcharging leading to an overall cationic charge. This has to be avoided because overcharging results in a dramatic reduction in wet-end performance, overall retention and formation, of the paper machine.
In the paper industry there is an increasing demand for dry strength. This demand is a result of the following trends: use of more cheap and/or secondary cellulose fibres, the increase in filler content in the paper sheet and the use of a pre-metering size press. Therefore, there exists an increasing need for new wet-end starches which allows for increasing the addition levels in the wet-end without the risk of overcharging the cellulose fibres and fillers.
In accordance with the invention it has surprisingly been found that the use of a hydrophobic starch as dry strength agent avoids neutralisation of the anionic charges on both cellulose fibres and fillers, while having a strong binding affinity to the cellulose fibres and fillers, thereby providing the required contribution to paper strength.
The use of a hydrophobic starch as dry strength agent does not have any substantial influence on the overall charge balance in the wet-end of the papermaking process. It can therefore be used in higher amounts than conventional dry strength agents without disturbing the wet-end performance, overall retention and formation at the paper machine.
Hydrophobic groups have a low affinity for an aqueous environment. When added to water, hydrophobic groups show a strong tendency to avoid contact with water molecules. In the presence of solid particles, like cellulose fibres and the filler materials used in papermaking, it has been found that the hydrophobic starch tends to adsorb to these particles, rather than staying in the aqueous phase. Without wishing to be bound by theory, it is postulated that this behaviour explains the binding capacity and performance of the hydrophobic starch as dry strength agent in the wet-end of papermaking.
The international patent application WO 99/55964 discloses a process for the production of paper from a suspension containing cellulosic fibres which comprises adding to the suspension a drainage and retention aid comprising a cationic or amphoteric polysaccharide, forming and dewatering the suspension on a wire, wherein the cationic polysaccharide has a hydrophobic group. The degree of substitution (DS) of anionic groups for the polysaccharide is from 0 to 0.2. However, the polysaccharide is also substituted with cationic groups and the DS of cationic groups is from 0.01 to 0.5, preferably from 0.025 to 0.2. The DS of cationic groups is always higher than that of anionic groups, making these polysaccharides overall cationically charged. Therefore, the binding mechanism to the fibres is still in accordance with the charge interaction mechanism.
The international patent application WO 2004/031478 discloses a cationised polysaccharide product comprising a polysaccharide having at least one first substituent having an aromatic group and at least one second substituent having no aromatic group, wherein the first substituent and the second substituent are present in a molar ratio in the range of 10:1 to 1:10. Also disclosed is a process for making paper wherein the cationised polysaccharide is added to an aqueous suspension containing cellulosic fibres.
The hydrophobicity of aliphatic groups is dependent on the number of carbon atoms. Compared to aromatic groups with the same number of carbon atoms, the aliphatic carbon chain is more hydrophobic. In accordance with the invention it has surprisingly been found that hydrophobic anionic starches bearing an aliphatic carbon chain, with an overall negative charge density between 0 and −0.09 μeq/mg exhibit a high affinity for solid particles in the wet-end. Thus, in accordance with the invention there is a preference for hydrophobic starches having an overall negative charge density between 0 and −0.09 μeq/mg, and a greater preference for such starches having an overall negative charge density between −0.005 and −0.07 μeq/mg.
The dry strength agent in accordance with the invention is a hydrophobic starch which may, in principle, be derived from any botanical source. Both root or tuber starches, such as cassava or potato starch, and cereal and fruit starches, such as maize, rice, wheat or barley starches can be used. Legume starches, such as pea or bean starches, can also be used. In a preferred embodiment, the starch is a root or tuber starch, more preferably potato or cassava starch.
Natural starches typically have a more or less fixed ratio of the two components of starch, amylose and amylopectin. Of some starches, such as maize or rice starch, a natural occurring variety exists which contains essentially only amylopectin. These starches, which are normally called waxy starches, can also be used. Of other starches, such as potato or cassava starch, there are genetically modified or mutant varieties, which also essentially only contain amylopectin. It will be understood that the use of these varieties, typically comprising more than 80 wt. %, preferably more than 95 wt. %, based on dry weight of the starch, of amylopectin, is also within the scope of the invention. Finally, also starch varieties that are high in amylose, such as high amylose potato starch, can be used for the preparation of a dry strength agent according to the invention. In accordance with the invention, starches of all amylose to amylopectin ratios may be used. However, it is preferred that a starch is used having a regular or increased amylopectin content.
The starch for making a hydrophobic starch in accordance with the invention is preferably a native starch. However, if desired, the molecular weight of the starch may be decreased or increased by any method known in the art, such as acidic degradation or oxidation, prior to or simultaneous with the introduction of the hydrophobic group.
DESCRIPTION OF THE INVENTION
In accordance with the invention, a hydrophobic starch is a starch that has been modified by etherification, esterification or amidation with a hydrophobic reagent comprising an aliphatic and/or aromatic group and has from 4-24 carbon atoms, preferably from 7-20 carbon atoms, more preferably 12 carbon atoms. It is preferred that the hydrophobic reagent is based on an aliphatic group.
The hydrophobic starch may be prepared by attaching a hydrophobic substituent to the starch by an ether, ester or amide group. When the hydrophobic group is attached to the starch via an ether linkage, the hydrophobic reagent preferably comprises a halide, halohydrin, epoxide or glycidyl group as reactive site. The alkyl chain of the agent can vary from 4-24 carbon atoms, preferably from 7-20 carbon atoms. Suitable examples of hydrophobic reagents to provide an ether linkage are cetyl bromide, lauryl bromide, butylene oxide, epoxidized soybean fatty alcohols, epoxydized linseed fatty alcohols, allyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, decane glycidyl ether, lauryl glycidyl ether, lauryl phenyl glycidyl ether, myristoyl glycidyl ether, cetyl glycidyl ether, palmityl glycidyl ether, stearyl glycidyl ether, linolyl glycidyl ether and mixtures thereof. Other etherification agents which may be used to react with starch in accordance with the invention are alkyl halides containing at least four carbon atoms, such as 1-bromodecane, 10-bromo-1-decanol, and 1-bromododecane.
In a preferred embodiment a charged hydrophobic group is introduced. A hydrophobic cationic group can be attached via an ether linkage by reaction of the starch with a reagent comprising a quaternary ammonium group, for example a 1-chloro-2-hydroxypropyltrialkyl ammonium salt or a glycidyltrialkyl ammonium salt. The alkyl chains of this quaternary ammonium group can vary from 1-24 carbon atoms, preferably from 7-20 carbon atoms, wherein at least one of the alkyl chains of the quaternary ammonium group comprises 4-24 carbon atoms. Preferably, the other alkyl chains have less than 7 carbon atoms. For example (3-chloro-2-hydroxypropyl)dimethyl dodecylammonium salt, 1-chloro-2-hydroxypropyldimethyllauryl ammonium salt, 1-chloro-2-hydroxypropyldimethylmyristoyl ammonium salt, 1-chloro-2-hydroxypropyldimethylcetyl, 1-chloro-2-hydroxypropyldimethylstearyl, glycidyldimethyllauryl ammonium salt, glycidyldimethylmyristoyl ammonium salt, glycidyldimethylcetyl ammonium salt, glycidyldimethylstearyl ammonium salt, dialkylaminoethyl halide, or mixtures of the above can be applied as hydrophobic cationization reagent. A hydrophobic cationic group may be introduced by reaction with tertiary ammonium groups such as chloroethyldialkylamine hydrogen chloride salt. The alkyl chain of this tertiary ammonium group may vary from 1 to 24 carbon atoms. The reaction for introducing the hydrophobic cationic group may be performed analogous to the procedure disclosed in EP-A-0 189 935. A hydrophobic anionic group can be attached applying a 2-chloro-aminodialkyl acid as reagent, for instance analogous to the procedure disclosed in EP-A-0 689 829.
When the hydrophobic group is attached to the starch via an ester linkage, several kinds of reagents, such as alkyl anhydrides can be applied. The alkyl chain can vary from 4-24 carbons, preferably from 7-20 carbons. Especially, mixed anhydrides as octanoic acetic anhydride, decanoic acetic anhydride, lauroyl acetic anhydride, myristoyl acetic anhydride are suitable alkyl anhydrides.
In a preferred embodiment, hydrophobic anionic groups may be attached to the starch. This may be accomplished by reaction of the specific starch with an alkyl succinic anhydride or alkenyl succinic anhydride. Alkyl succinic anhydrides are preferred. The alkyl chain can vary from 4-24 carbons, preferably from 7-20 carbons. Octenyl succinic anhydride, nonyl succinic anhydride, decyl succinic anhydride, dodecenyl succinic anhydride are most commonly applied. The procedure in accordance with this embodiment may be performed analogous to the procedures disclosed in U.S. Pat. No. 5,776,476.
For the preparation of a hydrophobic group linked to carboxymethyl starch by an amide group the procedure as described in WO-A-94/24169 can analogously be applied. Examples of suitable reagents for introduction of an amide group include fatty amines comprising saturated or unsaturated hydrocarbon groups having from 8 to 30 carbon atoms. Branched hydrocarbon groups are not excluded, but linear chains are preferred. Preferably, the fatty radical originates from a C 12 to C 24 fatty amine. Particularly favorable results are obtained if the fatty amine is selected from the group consisting of n-dodecylamine, n-hexadecylamine, n-octadecylamine, cocoamine, tallowamine, hydrogenated N-tallow-1,3-diaminopropane, N-hydrogenated tallow-1,3-diaminopropane, and N-oleyl-1,3-diaminopropane. Such fatty amines are known under the trade names Armeen and Duomeen (AKZO Chemicals).
The degree of hydrophobic substitution, i.e. DS, defined as the average number of moles of hydrophobic substituents per mole glucose units, achieved in a process according to the invention, may vary depending upon the presence of other substituents in the starch prior to the hydrophobation, the type of hydrophobic reagent used, and the envisage application of the product. According to the invention the DS is from 0.0001 to about 0.01, more preferably from 0.002 to 0.008. It is surprising to note that even a very small DS leads to a relatively large effect.
The hydrophobation of the starch may be performed under semi-dry reaction conditions, in suspension (water or organic solvent), in aqueous solution (dispersion), or during the gelatinization of the starch granules. It is also possible to perform the hydrophobation in an extruder at increased temperature and pressure. According to the latter embodiment, it is possible to perform the reaction continuously. The moisture content is preferably smaller than 25% when the reaction is carried out in an extruder.
Preferably, water is used as a solvent when the reaction is performed in suspension. When the hydrophobic reagent has a low solubility in water, combinations of water and suitable water mixable organic solvents may be employed. Suitable organic solvents include, but are not limited to, methanol, ethanol, i-propanol, n-propanol, t-butanol, sec-butanol, methylethylketone, tetrahydrofuran, dioxan, and acetone.
The reaction in aqueous solution is preferably performed using a reaction mixture comprising more than 20 wt. % of the starch or derivative thereof and less than 80 wt. % of the solvent. More preferably, the starch content in the reaction mixture lies between 20 and 40 wt. %, whereas the solvent content preferably lies between 80 and 60 wt. %. An autoclave in combination with a dryer (drum dryer; spray dryer) or an extruder is preferably used as a reaction vessel. The reaction is further performed under conditions which are well-known for analogous reactions. The pH lies preferably between 7 and 13.
Preferably, the hydrophobic starch is prepared in the presence of a caustic catalyst, such as an alkali metal hydroxide or the like material. In accordance with specific embodiments, the caustic catalyst is used in such amounts that it is in fact present as a reagent.
Further, it has been found that the reaction for preparing a hydrophobic starch can be accelerated by the presence of one or more surfactants in the reaction mixture. Suitable surfactants are characterized by the ability to facilitate bringing the hydrophobic reagent in contact with the hydrophilic starch, so reaction can take place (phase-transfer catalysis). In accordance with this embodiment, the reaction is preferably performed while the reaction mixture is stirred. Surfactants can be applied in any of the above mentioned reaction systems. The surfactants which may be used include nonionics, anionics, cationics or amphoterics, singly or in combination provided they are compatible with the other components of the reaction system and they are capable to facilitate bringing the hydrophobic reagent in contact with the hydrophilic starch. Examples of suitable surfactants are higher fatty alcohol sulfates, such as a sodium or potassium sulfate of an alcohol having from 8 to 18 carbon atoms, alkylphenoxypolyethoxyethanols, such as octylphenoxypolyethoxyethanols, alkyltrimethylammonium halides and alkyltributylammonium hydroxides, such as tetramethylammonium hydroxide and cetyltrimethylammonium bromide, alkyl acids, such as stearic acid, an ethylene oxide condensate of a long-chain alcohol, such as lauryl, or cetyl alcohol, polyoxyethylene sorbitan stearate, and many others. Preferably, the surfactant comprises a branched alkyl chain or multiple alkyl chains. The amounts wherein the surfactants are used may vary between 0.1 and 10 wt. %, based on dry substance of starch.
In a preferred embodiment, the hydrophobic starch is also crosslinked. Crosslinking may be performed in any known manner. Examples of suitable manners for obtaining the desired derivatives are for instance disclosed in “Modified Starches: Properties and Uses”, O. B. Wurzburg, CRC Press Inc., 1987. In a crosslinking reaction, the hydrophobic starch is treated with a reagent, a crosslinking agent, having two or more reactive groups. The crosslink agent is preferably attached to the starch via ester and/or ether linkages. Examples of suitable reactive groups are anhydride, halogen, halohydrin, epoxide or glycidyl groups, or combinations thereof. Epichlorohydrin, sodium trimetaphosphate, phosphorous oxychloride, phosphate salts, chloroacetic acid, adipic anhydride, dichloroacetic acid, and combinations thereof have been found to be suitable for use as crosslinking agents. It is preferred that the crosslinking agent is added to the reaction mixture in which the hydrophobation reaction is carried out. The crosslinking reaction may be carried out before, simultaneous with, or after the reaction that introduces the hydrophobic group. It is preferred that both reactions are carried out simultaneous.
The hydrophobic starch may be used as dry strength agent in the wet-end of papermaking in an amount that will depend on the kind of pulp that is used, the working conditions and the desired paper properties. Preferably, 0.05 to 10 wt. % and more preferably 0.1 to 3 wt. % of hydrophobic starch, dry substance, calculated on the paper pulp, dry substance, is used.
The hydrophobic starch is preferably first gelatinized in water. The resultant starch solution, optionally after further dilution, is added to the pulp mass. It is also possible, however, to mix pre-gelatinized hydrophobic starch with the pulp mass, either as dry product or after dissolution in water).
It is contemplated that the hydrophobic starch is used in combination with other dry strength agents, such as conventional cationic or anionic starches. In the case of anionic starches, it may be desired to also use fixative, as is described in WO-A-93/01353 and WO-A-96/05373. For an optimal binding of non-hydrophobic anionic starches to fibers and fillers in the wet-end, as described in the prior art, the use of a cationic fixative is necessary. Surprisingly it has been found that for the use of a hydrophobic starch as dry strength agent according to the invention, a fixative need not be used as it binds to the fibres and fillers.
The hydrophobic starch can be added at any point in the papermaking process, although it will generally be added in the wet-end, i.e. before formation of the paper sheet on the sieve. For example, it can be added to the pulp while it is disposed in the head box, the Hollander, the hydropulper or the dusting box.
The pulp used for the papermaking will generally be an aqueous suspension of cellulosic fibres, synthetic fibres, or combinations thereof, optionally containing fillers. Among the cellulosic materials which may be used are bleached and unbleached sulfate (kraft), bleached and unbleached sulfite, bleached and unbleached soda, neutral sulfite, semi-chemical, thermomechanical, chemithermomechanical, chemiground wood, ground wood, recycle or any combination of these fibers. Fibers of the viscose rayon, regenerated cellulose, cotton and the like may also be used if desired.
Any desired inert mineral fillers may be added to the pulp which is to be utilized with the dry strength agent according to the invention. Such materials include clay, titanium dioxide, talc, calcium carbonate, calcium sulfate and diatomaceous earths. Rosin may also be present, if desired.
Other additives commonly introduced into paper may be added to the pulp or furnish, for example, dyes, pigments, sizing additives, alum, retention aids, etc.
In addition to the selected dry strength agent and other components that may be included in the papermaking system as described above, colloidal inorganic minerals may be added to the system to form an alkaline microparticle system. Such microparticle systems include colloidal silica, bentonite, or the like and may be incorporated into the system in amounts of at least 0.001% and more particularly from about 0.01 to 1% by weight based on the weight of dry pulp. Further description of such microparticle inorganic materials may be found in U.S. Pat. No. 4,388,150, U.S. Pat. No. 4,643,801, U.S. Pat. No. 4,753,710 and U.S. Pat. No. 4,913,775.
The amount of the dry strength agent that may be added to the wet-end or paper pulp will be an effective amount to provide the desired property (e.g. strength, drainage or retention). Typically an amount from about 0.05 to 5% of the starch derivative, most suitably from about 0.1 to 2%, by weight based on the dry weight of the pulp will be used.
One embodiment of this invention is that the dry strength can be added directly, i.e. in dry form, to the papermaking system at any convenient place, where elevated temperatures exist, before the formation of the sheet. Examples can include, but are not limited to, the head box, pulper, machine chest, blend chest, stuff box or white water tray. Alternatively, the dry strength agent can be dispersed into water before being added to the papermaking process. Typically this is accomplished by slurrying the granular starch product at about 0.1 to 30 percent solids into water and adding directly to the machine prior to the head box. The slurry may be heated between about 40 and 100° C., particularly between 60 and 70° C., or the starches can be added to preheated water from any source. It is advantageous to use recycled water from common processes in the papermill, such sources could include the whitewater, or other equipment or processes that produce warm/hot water as a by-product of their operation. While it is ideal to disperse these starches into water at less than 100° C., it would be obvious to one skilled in the art to cook these starches at typical elevated temperatures. Examples of the cooking techniques that could be used are jet cooking, batch cooking, steam injection, pressure-cooking and the like.
When prepared as described above, the dry strength agent according to the invention provide the papermaker many advantages over what is currently available. Being easy to prepare and requiring less temperature to disperse the granular starch results in energy and equipment savings and reduced worker exposure to high temperature liquids and hot equipment. In addition to the typical benefits obtained from traditional starches, the derivatives of this invention provide better resistance to the shear of today's high speed machines and pumps. Improved strength, particularly in high conductivity or partially closed systems, affords papermakers the ability to prepare sheets lighter in weight and thus save on pulp costs.
The invention will now be elucidated by the following, non-restrictive examples.
EXAMPLES
Example 1
Hydrophobic starch derivatives were prepared by reacting potato starch with (3-chloro-2-hydroxypropyl)dimethyl dodecylammonium chloride (QUAB 342, QUAB Chemicals) according to the general procedure described in EP 0 603 727. In some cases, sodium trimethaphosphate was added (250 mg/kg), to achieve a simultaneous crosslinking. The degree of substitution of QUAB 342 was 0.004, 0.006 and 0.008.
The thus obtained dry strength agents were dissolved in water with live stream at 10% concentration. Brookfield viscosity was measured in 5% concentration at 50° C. (60 rpm). The starch solutions were diluted to 1%. The charge density was measured from a diluted solution using minusil as carrier, and 1 mM methyl glycol chitosan as titrant with a Malvern Zetasizer 3000.
The adsorption of the starches on to solid pulp components was studied as follows. To a pulp 1.6% starch (dry-on-dry) was added and after 60 second the pulp was filtered. For comparison also native potato starch and a standard cationic wet-end starch, Amylofax PW (DS chlorohydroxypropyl trimethyl ammonium chloride of 0.035), were studied. The starch adsorptions were determined by measuring the amount of non-adsorbed starch in the filtrate. The pulp was a birch sulphate pulp beaten to 32° SR (measured at 21° C.) at a consistency of 2% in tap-water using a Hollander. After beating the pulp was diluted to a consistency of 1% with tap-water. The conductivity was set to 1500 μS/cm by the addition of NaCl. The amount of starch in the filtrate was determined with an enzymatic method. In accordance with this method, starch is first converted to glucose with α-amylase and an aminoglucosidase.
Subsequently, the amount of glucose is determined spectroscopically using a hexokinase test method (Raisio diagnostics). The amount of starch is calculated from the obtained amount of glucose using a correction factor for incomplete conversion of the starch into glucose by the enzymes. This correction factor depends on the type of starch and was determined separately by standard methods. The Zeta potential of the pulp was measured with the Malvern Zetasizer 3000.
An overview of the starch adsorptions for the starches is given in Table 1.
TABLE 1
DS
Starch
QUAB
Brook-
Charge
adsorp-
Zeta
342
Cross-
field
density
tion
potential
Starch
(mol/mol)
linker
(mPa · s)
(μeq/mg)
(%)
(mV)
Potato
None
None
440
−0.07
32
−3.3
starch
QUAB
0.004
None
420
−0.04
56
−3.2
0.004
QUAB
0.006
None
600
−0.03
68
−3.1
0.006
QUAB
0.008
None
570
−0.005
77
−2.9
0.008
QUAB
0.004
Yes
1500
−0.04
83
−3.5
0.004C
QUAB
0.006
Yes
1900
−0.02
89
−3.6
0.006C
QUAB
0.008
Yes
1550
−0.002
93
−3.2
0.008C
Amylofax
None
None
380
+0.31
91
+2.7
PW
From these results can be seen that all the hydrophobic QUAB derivatives exhibit an overall negative charge density. A regular cationic wet-end starch, like Amylofax PW, exhibits a positive charge density. The starch adsorption is low for native potato starch. By the introduction of hydrophobic groups the starch adsorption is increased considerably and with the combination of hydrophobation and crosslinking the adsorption is further improved. With a standard cationic wet-end starch like Amylofax PW also high starch adsorption is achieved at 1.6% addition level, but in this case the Zeta potential of the fibres has changed from negative to positive. With the new hydrophobic wet-end starches the Zeta potential is still negative at addition levels of 1.6%.
Example 2
Mixtures of the hydrophobic starch derivatives describe in example 1 and Amylofax PW (ratio 1:2) were prepared and tested according to the procedure described in example 1. An overview of the starch adsorptions is given in table 2.
TABLE 2
Starch
DS
Brook-
Starch
Zeta
mixtures
QUAB 342
Cross-
field
adsorp-
potential
(2:1)
(mol/mol)
linker
(mPa · s)
tion (%)
(mV)
Amylofax PW/
None
None
790
76
−2.1
native potato
starch
Amylofax PW/
0.004
None
590
84
−0.5
QUAB 0.004
Amylofax PW/
0.006
None
580
88
−1.0
QUAB 0.006
Amylofax PW/
0.008
None
570
91
−2.2
QUAB 0.008
Amylofax PW/
0.004
Yes
815
95
−0.7
QUAB 0.004C
Amylofax PW/
0.006
Yes
700
96
−1.2
QUAB 0.006C
Amylofax PW/
0.008
Yes
650
97
−0.8
QUAB 0.008C
Amylofax PW
None
None
380
91
+2.7
From these results can be seen that also in combination with traditional cationic starches the hydrophobic starches according to the invention exhibit a good starch adsorption performances at 1.6% dosage without overcharging the cellulose fibers.
Example 3
Hydrophobic starch derivatives were prepared by reacting potato starch with N-(3-chloro-2-hydroxypropyl)-N-benzyl-N,N-dimethylammonium chloride (Benzyl reagent) according to the procedure described in Example 1. In some cases, sodium trimethaphosphate was added (250 mg/kg), to achieve a simultaneous crosslinking. The degree of substitution of Benzyl reagent was 0.004, 0.006 and 0.008. These hydrophobic starch derivatives were tested according to the procedure described in example 2 (2:1 mixture of Amylofax PW and Benzyl derivative). An overview of the starch adsorptions for the starches is given in table 3.
TABLE 3
Starch
DS
Charge
Brook-
Starch
adsorp-
Benzyl
Cross-
density
field
mixtures
tion
Starch
(mol/mol)
linker
(μeq/mg)
(mPa · s)
(2:1)
(%)
Benzyl
0.004
None
−0.06
390
Amylofax
76
0.004
PW/Benzyl
0.004
Benzyl
0.006
None
−0.02
360
Amylofax
76
0.006
PW/Benzyl
0.006
Benzyl
0.008
None
−0.01
360
Amylofax
77
0.008
PW/Benzyl
0.008
Benzyl
0.004
Yes
−0.02
2050
Amylofax
92
0.004C
PW/Benzyl
0.004C
Benzyl
0.006
Yes
−0.02
1700
Amylofax
90
0.006C
PW/Benzyl
0.006C
Benzyl
0.008
Yes
−0.01
1600
Amylofax
94
0.008C
PW/Benzyl
0.008C
From these results can be seen that the starch adsorption is not dependent on the DS Benzyl. Therefore the benzyl group (C7) is the lower limit for the hydrophobic interaction according to the invention.
Example 4
Hydrophobic starch derivatives were prepared by reacting potato starch with octenyl succinic anhydride (OSA) according to the general procedure described in EP 1141030 B1. In some cases, sodium trimethaphosphate was added (250 mg/kg), to achieve a simultaneous crosslinking. The degree of substitution of octenyl succinic anhydride was 0.004, 0.006 and 0.008. These hydrophobic starch derivatives were tested according to the procedure described in example 1. An overview of the starch adsorptions for the starches is given in Table 4.
TABLE 4
Starch
Zeta
Brook-
Charge
adsorp-
po-
OSA
Cross-
field
density
tion
tential
Starch
(mol/mol)
linker
(mPa · s)
(μeq/mg)
(%)
(mV)
OSA 0.004
0.004
None
430
−0.09
28
−4.8
OSA 0.006
0.006
None
560
−0.10
30
−4.9
OSA 0.008
0.008
None
490
−0.12
34
−4.9
OSA 0.004C
0.004
Yes
1610
−0.09
67
−5.0
OSA 0.006C
0.006
Yes
1650
−0.10
68
−4.5
OSA 0.008C
0.008
Yes
2200
−0.11
72
−4.8
From these results can be seen that a charge density below −0.09 μeq/mg is most preferable for hydrophobic interaction according to the invention. | The invention relates to the field of papermaking. More in particular, the invention relates to the use of a novel dry strength agent in the wet-end of the papermaking process. | 3 |
This is a continuation of application Ser. No. 173,874 filed July 30, 1980 now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to non-incursive diagnostic apparatus. More particularly, it relates to image display and recording means for such diagnostic apparatus.
In the art relating to diagnostics, especially in the field of medical diagnostics, means have been provided for examining the interior of a body by measuring the intensity of energy reflected from body members or transmitted through body members. One preferred form of such examination is by the use of ultrasonic pulse energy transmitted into the body member by a scanning transducer, with the sonic energy being reflected by elements within the body and received by the same or similar transducer. In the case of such an ultrasonic scanning system, the body portions examined comprise a fan shaped sector covering for example, an angle of 30 to 75 degrees. The reconstructed image, when displayed, also presents a representation covering an angle of the same 30 to 75 degrees. The width of the angle is a function of the desired scanning angle of the transducer. The display appears as an array of radial lines with each line having portions of variable density depending upon the intensity of the reflected signal. It will be appreciated that, the wider the scan of the transducer, the greater will be the separation between adjacent radial lines. The number of radial lines is a function of the pulse repetition rate of the initiating sonic pulses and the scan frequency of the transducer. In one such system, the relationship was such as to produce 100 radial lines per scan. While the discrete radial lines are adequate to convey the desired medical information to a trained observer, the gaps, or spaces, between the discrete lines presents an undesirable image pattern which is difficult to read.
SUMMARY OF THE INVENTION
It is, accordingly, an object of the present invention to provide an improved image display means.
It is another object of the present invention to provide means for effecting an improved display of pulsed image data.
In accomplishing these and other objects, there has been provided, in accordance with the present invention, a digital circuit for interpolating the intensity values between adjacent pulsed data signals. The interpolation includes, effectively, providing a plurality of shades of gray between adjacent received data. The interpolation data is applied to the display means to effectively fill the interstices between the adjacent image lines. When thus applied, the resultant image is one of a smooth transition between adjacent analog data thereby constituting a more readily readable and desirable display of the image.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention may be had from the following detailed description when read in the light of the accompanying drawings, in which:
FIG. 1 is a schematic block diagram of a image data display and recording system incorporating the present invention;
FIG. 2 is a schematic block diagram of a circuit embodying the present invention, and comprises one portion of the system shown in FIG. 1;
FIG. 3 is a pictorial representation of an image produced without the benefit of the present invention, and
FIG. 4 is a pictorial representation of an image produced using the present invention.
DETAILED DESCRIPTION
Referring now to the drawings in more detail, there is shown in FIG. 1 a diagram of a system embodying the present invention. Specifically, there is shown a transducer 2. The transducer 2 is driven to produce series of ultrasonic pulses by a transducer drive circuit 4. The drive circuit 4 is of conventional and well-known design. The sonic signals reflected from the body are detected by the transducer 2 and converted to corresponding electrical signals varying in amplitude with the intensity of the reflected signals. These electrical signals are applied to the input of a receiver 6 for amplification. The output of the receiver 6 is applied to the input of an analog-to-digital (A to D) converter 8. The output of the analog-to-digital converter 8 is applied to the input of a line buffer 10, the output of which is, in turn, applied to the input of a coder 12. The coder puts the digital data from the buffer into a preferred form for storage in an image memory 14. The image memory 14 is, in turn, controlled by an array processor 16 which is programmed to store the data in the memory in a pattern corresponding to the scan sector of the transducer.
The output of the image memory is applied to the input of a fill circuit, or interpolator, 18. The fill circuit or interpolator 18 will be discussed in greater detail hereinafter. The output of the fill circuit 18 is applied to the input of a digital-to-analog (D to A) converter 20, the output of which is applied to the input of an unblanking circuit 22. The unblanking circuit 22 controls the beam intensity or Z axis modulation of a display CRT 24 and of a recording CRT 26. A suitable deflection circuit 28 controls the deflection of the beam in each of the CRT's 24 and 26. In the case of the display CRT 24, the deflection circuit 28 controls the X and Y axis deflection of the beam, while in the recording CRT 26, it is essentially the X axis deflection that is controlled. The recording CRT is preferably of the type having a narrow band of fiber optic elements across the face plate thereof to define a recording area.
In operation the transducer driver circuit 4 energizes the transducer 2 to produce a series of ultrasonic pulses which are radiated into the body to be examined. A portion of the pulse energy is returned to the transducer 2 by reflection from organic structures within the body under examination in accordance with known technology. The energy received by the transducer is converted to corresponding analog electrical signals which are received and amplified by the receiver 6. The amplified analog signals are converted to corresponding digital values by the analog-to-digital converter 8. The digital data corresponding to the analog signals is assembled in the buffer 10 and then passed through the coder 12, (more about which will be said hereinafter) to be stored in the image memory 14. The array processor 16 associated with the image memory 14 is coordinated with the scanning angle of the transducer 2 and controls the addressing of the data into the image memory in a pattern to correspond to the scanning angle of the transducer. The stored data is then read from the image memory 14 on a line-by-line, or raster scan basis and applied to the input of the fill or interpolation circuit 18.
In a preferred embodiment, the fill circuit 18 may be selectively included in the circuit or bypassed. The digital data is then supplied to the digital-to-analog converter 20 where the digital values are reconverted to analog signals and applied as Z axis modulation to the unblanking circuit 22 for either or both of the two CRT devices 24 and 26. The display presented on the face of the CRT 24 will be in the form of a sector display corresponding to the angular scan of the transducer, with the analog signal appearing as areas as variable density within the scan sector. It is anticipated that a photosensitive recording medium will be moved at a predetermined speed past the face of the recording CRT 26 in accordance with known techniques. The resulting image on the recording medium would, again, be in the form of a sector display coresponding to the angular scan of the transducer 2 with the analog data appearing as areas of variable density within that scan sector.
As was previously noted, without the use of the fill circuit, the image appearing both on the display tube 24 and on a record made from the recording CRT 26, will be in the form of a succession of laterally disconnected dots arranged as an array of radial lines, such as is shown in FIG. 3. On the other hand, when the fill circuit or interpolation circuit 18 is connected in use, the image on the face of the display CRT 24 and on the record formed from the recording CRT 26 will appear with the laterally disconnected dots now connected by interpolated shades of gray to produce a smoother image such as that shown in FIG. 4. As may be seen from a comparison of FIGS. 3 and 4, the recorded data in FIG. 3 appears as a number of radial lines each spaced from the next adjacent line with the data appearing as variable density marks representing the individual data units. In FIG. 4, however, there has been an interpolation of data between the distinct radial lines to fill in appropriate data to provide the smoother image pattern.
In the accomplishment of the interpolation, it is desirable that no interpolation or fill be spread into true zero areas, such, for example, as beyond the edges of the fan shaped sector. In accordance with a system constructed in accordance with the present invention, the A to D converter 8 converts the analog information into four bit data words representing 16 shades of gray, or digital values from zero to 15. In order to avoid spilling the interpolation over into the non-data portions of the display, i.e., beyond the edges of the fan shaped sector, the coder 12, in FIG. 1, forces all of the words of value zero in the significant data stream to become words of value one. This conversion, of course, applies only to the data received from the transducer and transmitted through the A to D converter to the coder 12. This arrangement provides for a positive distinction between image data and true zero or background data. Thus the data stored in the image memory 14 in the pattern of the fan shaped sector will range in value between 1 and 15 whereas the data surrounding the fan shaped image will be all logical zeros. Similarly, the memory data cells or pixels between the radial lines of data in the image memory will also be logical zeros or data spaces. The data stored in the image memory is read out in a line by line or raster scan and applied to the input of the fill circuit 18, as shown in FIG. 1.
The fill circuit 18 is shown in greater detail in FIG. 2. The input terminal of the fill circuit 18 is connected first to a gray data input of a first-in first-out (FIFO) memory unit 30. The output of the image memory 14 is also applied to the input of a zero data or data space counter circuit 32 which includes a detector to detect the data spaces as well as a counter to count them. The output of the zero data counter 32 is applied to a second input of the memory unit 30. The FIFO memory unit 30 may, in practice, be formed of two or more memory chips such as those designated as 74S225 produced by Texas Instruments. The zero data counter 32 includes means for detecting the number of zero data units between adjacent non-zero data units. The count thus generated is stored in the one portion of the FIFO memory unit 30. In the other portion of the FIFO memory unit 30 the non-zero data units, representative of the intensity of the signal produced by the transducer in response to the reflected sonic energy, is stored. That intensity responsive data will be hereinafter referred to as gray data. The output gray data from the FIFO 30 is applied to the input of an old value register 34, the output of which is applied to one input terminal of an adder or summer 36. The gray data output of the FIFO 30 is also applied directly to a second input of the summer 36. The summer 36 provides an output signal which is representative of the digital difference between the old value or the immediately preceding value of the gray data and the current value of the gray data.
The output of the summer 36 is applied as one input to a Read Only Memory (ROM) unit 38. The zero count output of the FIFO memory unit 38 is applied as a second input to the ROM 38. The two input circuits to the ROM 38 effectively comprise address signals for the unit 38. Values which were previously stored in the ROM 38 are such that the output signal from the ROM 38 comprises a fraction signal which is representative of the difference signal from the summer 36 divided by a number representative of the zero count, plus one. This relationship will be set forth more fully hereinafter.
The zero count from the FIFO memory unit 30 is also applied as an input signal to a preset counter 40. The output of the counter 40 is applied as an input signal to a decode circuit 42. The output signals from the ROM 38 are applied as a first input signal to a second summing circuit 44. The output of the summer 44 is applied to one input of a multiplexer 46. The second input to the multiplexer 46 is connected to the output of the old value register 34. The output of the decode circuit 42 is connected to control the selective operation of the multiplexer 46.
The output of the multiplexer 46 is applied as an input signal to a buffer register 48 which is controlled by a dot clock circuit 50. The output of the register 48 is connected to the second input of the summer circuit 44. The output of the register 48 is also applied as one input signal to an output selector multiplexer 52. A second input of the multiplexer 52 is connected to the output of the image memory 14. The output of the multiplexer 52 is applied to the input of the digital to analog converter 20. The multiplexer 52 is controlled by a select signal which may be manually controlled. The multiplexer 52 is, effectively, an output selector switch by which the fill circuit may be selectively incorporated into the data stream or bypassed if the interpolated data is not desired.
In operation, the image memory 14 is scanned on a line by line basis. Before each cycle of data is loaded into the image memory, that memory is controlled to clear all addresses or pixels to zero. The data received from the A to D converter 8 through the buffer 10 and the coder 12 are loaded into the assigned addresses in the image memory 14 under the control of the array processor 16. As before noted, the data received from the transducer and converted by the A to D converter is limited by the coder 12 to a minimum value of one on a scale of zero to 15 corresponding to the relative intensity of the signal received by the transducer.
The signals received by the transducer are serial strings of data arranged in a succession of spaced radial lines. The array processor 16 is arranged to store the received data in the image memory 14 in the pattern corresponding to those spaced radial lines. The minimum value for the signals in any of the spaced radial lines will be a value of one on a scale of zero to 15. The pixels or data units in the memory between the spaced radial lines will contain logical zeros as will the data lying beyond the two edges of the fan shaped data area. When that data is read out of the image memory 14 in a line-by-line scanning order, the number of zero value in pixels between successive non-zero valued pixels are detected and accounted by the zero data counter 32 and stored in the zero count portion of the FIFO memory 30. The value of the data on a scale of zero to fifteen read from the image memory is stored directly into the gray data portion of the FIFO memory unit 30. The FIFO memory unit 30 is an asynchronous memory unt.
The zero count data is read into the preset counter 40 while the gray data is read simultaneously into the old value register 34 and the summer 36. From the edge of the display to the beginning of the fan shaped array, the gray data will be all zeros. It has been determined that in the radial line array of data there will be less than eight successive zeros between any two non-zero pixels in the data display. Therefore any succession of zeros counting eight or more is indicative of the presence of a true zero value. The eight or more zeros is recognized by the preset counter 40 and decoded by the decoder 22 to set the multiplexor 46 to read the old value, i.e., zero from the register 34, bypassing the interpolation. When the far edge of the fan shaped display has been reached, there will again be a number of zeros in excess of eight detected. Again the multiplexer will be actuated to read the last active data from the old value register 34 without interpolation to the zero level. This will, of course, be followed by all zeros from the register 34.
In the portion of the image memory in which the significant data is stored, the successive data values on each scan line are subtracted in the summer 36 to provide a value equal to the difference in intensity between the two successive data points on the scan line. The distance between those two data points is measured by the number of consecutive zeros counted by the zero data counter and transmitted through the FIFO 30. The objective of the interpolation system is to determine the magnitude of the difference between adjacent significant data bits, to divide that value by the distance between successive significant data cells, or pixels to produce a fractional value and to sum that fractional value with the last preceding value to produce a graduated transition between actual measured values over the space between measured values. To this end, when the leading edge of the fan shaped array is reached by the scanning of the image memory, the first sigificant value is transferred from the output of the old value register 34 into the multiplexer 46 and thence to the register 48. The difference between that old value and the next significant non-zero value is determined by the summer 36. The distance between successive non-zero values is determined by the zero data counter 32 and transmitted through the FIFO 30 to the second input of the ROM 38. The data stored in the ROM 38 is a table of fractional values representing possible gray scale values on a scale of one to fifteen divided by zero count numbers of one to eight. The one to eight divisors represents the actual count of zeros, plus one, since the number of samples to fill the spaces between adjacent non-zero values is one less than the actual count number. This principle is illustrated in counting the spaces between a predetermined number of pickets in a picket fence, the spaces being one less than the number of pickets. Accordingly, the difference signal from the summer 36 and the zero count number from the zero count portion of the FIFO memory unit 30 applied to the input of the ROM 38 select a value at an address determined by the two input signals which is the value representative of the difference signal divided by the count number plus one. That fractional value output from the ROM 38 is summed in the summer 44 with the previous value taken from the output of the register 48. The output of the summer 44 is then applied through the multiplexer 46 to the input of the register 48 where the value stored is now the previous value plus the fractional increment. That value is then applied through the multiplexer 52 to the digital-to-analog converter, thence to the display and recording apparatus. The new value in the register 48 is now returned to the summer 48 where it is again summed with the increment and again returned to the register and applied through the multiplexer 52 to the digital-to-analog converter. This process is continued until the desired number of increments have been added and a new non-zero value is received from the gray data portion of the FIFO memory 30. In this manner, the values corresponding to differing shades of gray between adjacent non-zero values of the gray data received into the FIFO 30 are properly interpolated to provide a fill for the spaces between the radial lines of the image scan. These values are then clocked out of the register 48 by the dot clock 50 at a rate corresponding to the frequency of the individual dot elements on the CRT devices.
When the next non-zero value from the gray data portion of the FIFO memory 30 is received at the output thereof, the old value register is updated to store the last previous value and is then compared with the new value of the non-zero gray data. The interpolation process is then repeated for these two values and each successive pair of values across each line scan of the image memory. In this manner, the displayed or recorded image resulting from the interpolation presents a more readable and more esthetically pleasant image than the disconnected samples represented in FIG. 3 hereof. If, for any reason, it is desired to not use the filled or interpolated image, a select signal is applied to the multiplexer 52 to transmit the data directly from the image memory to the digital-to-analog converter 20 thence onto the display 24 to produce an image such as that shown in FIG. 3.
Thus, there has been provided, in accordance with the present invention, an improved image display and recording apparatus wherein the data between scanned samples are interpolated to provide a filled or smoothed resultant image. This is particularly desirable in the display and/or recording of medical diagnostic images. | There has been provided, a digital circuit for interpolating the intensity values between adjacent pulsed data signals. The interpolation includes, effectively, providing a plurality of shades of gray between adjacent received data. The interpolation data is applied to the display means to effectively fill the interstices between the adjacent image lines. When thus applied, the resultant image is one of a smooth transition between adjacent analog data thereby constituting a more readily readable and desirable display of the image. | 6 |
This is a division of U.S. patent application Ser. No. 08/550,893, filed Oct. 31, 1995 now U.S. Pat. No. 5,694,761, which is a continuation of U.S. patent application Ser. No. 08/087,974, filed Jul. 7, 1993 now U.S. Pat. No. 5,461,854.
BACKGROUND OF THE INVENTION
This invention relates to gas turbine engines and more particularly to improved methods and apparatus for cooling the combustor and combustion gases of a gas turbine engine.
It is important to provide cooling for the combustor and combustion gases of a gas turbine engine in order to maintain the combustor, turbine, and combustion gas conduits of the engine below the temperature at which thermal failure occurs and to also limit the formation of nitric oxide (NO x ). Various methods and apparatus have been utilized in the past to achieve combustor and combustion gas cooling including passage of cooling air over and through the combustor, the injection of steam into the combustor cooling air, the injection of a water spray into the combustor cooling air, and various combinations of these methodologies and apparatuses. Whereas these prior art methodologies are useful in lowering the temperature of the combustor and combustion gases, the cooling is achieved through losses in the overall engine system since the work required to deliver the primary coolant, air, is excessive, and the quantity of energy recoverable with the small steam and/or water injection rates permitted is negligible.
SUMMARY OF THE INVENTION
This invention is directed to the provision of an improved gas turbine engine assembly.
More specifically, this invention is directed to the provision of an improved combustor for a gas turbine engine assembly.
Yet more specifically, this invention is directed to the provision of an improved method and apparatus for cooling the combustor and combustion gases of a gas turbine engine assembly.
The invention discloses a method of cooling the combustor and combustion gases of a gas turbine engine assembly of the type including a turbine and a combustor arranged to receive a fuel/air mixture and generate products of combustion within the combustor for delivery to the turbine.
According to the invention, a fluid is delivered to the combustor by a pump and is placed in heat exchange relation with the combustion products within the combustor so that thermal energy is absorbed from the combustion products by the fluid, and the fluid is thereafter injected into the combustion products for delivery with the combustion products to the turbine. This methodology allows combustor cooling to be achieved with a minimum of energy loss in the total system, thereby maximizing the overall efficiency of the total system.
In one embodiment of the invention, liquid is delivered to the combustor where it is placed in heat exchange relation with the combustion products before being injected into the combustion gases as liquid.
In a further embodiment of the invention, liquid id delivered to the combustor where it is placed in heat exchange relation with the combustion products before being injected into the combustion gases as gas or vapor.
In a further embodiment of the invention, gas or vapor is delivered to the combustor where it is placed in heat exchange relation with the combustion products before being injected into the combustion gases as gas or vapor.
According to a further feature of the invention methodology, the combustor has a central combustion chamber for containing the combustion products and an annular cooling chamber in surrounding relation to the central combustion chamber and having apertures communicating with the central combustion chamber; the step of placing the fluid in heat exchange relation with the combustion gases comprises delivering the fluid to the annular cooling chamber in its low energy liquid phase; condition; the conversion of the fluid to a higher level of energy occurs in the annular cooling chamber; and the step of injecting the fluid into the combustor comprises passing the fluid in its relatively high energy condition through the apertures and into the central combustion chamber.
According to a further feature of the invention, the turbine engine assembly includes a shaft driven by the turbine engine assembly includes a shaft driven by the turbine and a pump driven by the shaft and the fluid is delivered to the combustor by the pump.
The invention also provides an improved combustor for generating combustion products for delivery to a gas turbine. The improved combustor includes a central combustion chamber defining a central axis; a burner positioned to deliver products of combustion to one end of the chamber; a discharge at the other end of the chamber for delivering the combustion products to the turbine; and annular cooling chamber in surrounding relation to the central combustion chamber; an entry opening in the cooling chamber for receipt of a cooling liquid; and a plurality of apertures communicating the cooling chamber with the central combustion chamber. This combustor construction allows the cooling fluid to be placed in heat exchange relation to the combustor so that thermal energy is absorbed from the combustion products within the combustor before the fluid is injected in to the combustor through the apertures interconnecting the cooling chamber and central combustion chamber.
According to a further feature of the invention, the combustor is positioned with its central axis generally vertical; the burner is proximate the lower end of the combustion chamber; the discharge is proximate the upper end of the combustion chamber; and the entry opening in the cooling chamber is proximate the lower end of the combustion chamber. This specific arrangement and orientation of the combustor facilitates the placement of the cooling fluid in heat exchange relation to the combustion chamber.
The invention also provides an improved gas turbine engine assembly. The improved gas turbine engine assembly includes a turbine driving a shaft; a combustor operative to generate products of combustion for delivery to the turbine; a source of cooling liquid; and a pump driven by the turbine shaft, having an inlet connected to the liquid source, and having an outlet connected to the combustor. This arrangement allows a cooling liquid to be delivered to the combustor by a pump driven by the turbine, to improve the overall efficiency of the assembly.
According to a further feature of the invention, the combustor includes a central combustion chamber and an annular cooling chamber in surrounding relation to the central combustion chamber and connected to the combustion chamber by a plurality of apertures; the pump outlet is connected to the cooling chamber of the combustor by conduit means; and the assembly further includes a heat exchanger in the conduit means the heat exchanges receiving the discharge of the turbine. This arrangement allows the energy content of the cooling fluid to be increased by utilizing the waste products of the turbine.
According to a further feature of the invention, the assembly further includes means for delivering further energy to the fluid flowing through the conduit means. In the disclosed embodiment of the invention, the energy delivery means comprises a boiler arranged in the conduit interconnecting the pump to the cooling chamber of the combustor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective, partially cross sectional view of a gas turbine engine assembly according to the invention;
FIG. 2 is a somewhat schematic view of the gas turbine engine assembly of FIG. 1;
FIG. 3 is a somewhat schematic view of a modified form of the gas turbine engine assembly according to the invention; and
FIG. 4 is a somewhat schematic view of a still further modified form of the gas turbine engine assembly according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Each of the invention embodiments is of the type including a turbine 10 of know form having an inlet 10 a and outlet 10 b ; a combustor 12 arranged to deliver products of combustion to inlet 10 a of the turbine and thereby drive the turbine; a compressor 14 drive by shaft 16 of the turbine and including an inlet 14 a connected to a source of fuel and an outlet 14 b for delivering the fuel in pressurized form to the combustor; and a compressor 18 driven by shaft 16 and having an connected to a source of air and an outlet 18 b for delivering pressurized air to the combustor for mixture with the fuel from compressor 14 to provide a fuel/air mixture for combustion in the combustor to produce combustion products for delivery to the turbine to drive the turbine.
The invention provides an improved combustor 12 as well as an improved means of cooling the combustor.
The invention combustor has a generally cylindrical configuration and defines a central vertical axis 20 . Combustor 12 includes cylindrical outer wall 12 a ; a circular upper wall 12 b ; a circular lower wall 12 c ; an inner cylindrical wall 12 d defining a central cylindrical combustion chamber 22 and concentrically coacting with outer wall 12 a to define an annular cooling chamber 24 ; a plurality of apertures 12 e in inner wall 12 d providing communication between annular cooling chamber 24 and central combustion chamber 22 ; a central discharge aperture 12 f in upper wall 12 b ; an opening 12 g in lower wall 12 c within annular cooling chamber 24 ; and a burner 26 positioned centrally in lower wall 12 c . Apertures 12 e are arranged in vertically spaced rows with each row including a plurality of circumferentially and equally spaced apertures. The rows of apertures begin in the midregion of inner wall 12 d and extend upwardly to a topmost row proximate discharge aperture 12 f , that is, there are no apertures in the lower region 12 h of inner wall 12 d.
Burner 26 provides a pre-combustor for combustor 12 in the sense that the actual combustion process takes place within burner 26 utilizing air delivered to the burner from compressor 18 via a conduit 28 , and fuel delivered to the burner from compressor 14 via conduit 30 . The fuel and air are mixed within the burner and combusted within the burner to define flame front 32 within central combustion chamber 22 . Burner 26 may take various forms and, for example, may include a housing 26 a an electrode 26 b supplied by electrical conductors 34 and functioning in a known manner to combust the fuel and air mixture within housing 26 a for delivery into combustion chamber 22 to form flame front 32 . Burner 26 may, for example, comprise a gas, coal or fuel oil burner available from Maxon Corporation of Muncie, Indiana as Part No. WR-3. It will be understood that whereas the initial combustion of the fuel/air mixture occurs within burner 26 , post combustion also occurs within combustion chamber 22 . Discharge opening 12 f of the combustor is connected via hood 36 and conduit 38 to inlet 10 a of turbine 10 so that the products of combustion generated within combustion chamber 22 are delivered to the turbine inlet to drive the turbine.
The cooling of the combustor is accomplished by cooling chamber 24 in coaction with pump 40 and conduit 42 . Pump 40 is a liquid pump and may take various forms, including a gear pump, a lobe pump, a rotary pump or a centrifugal pump. A centrifugal pump is illustrated and includes an inlet 40 a connected to a source (not illustrated) of liquid such as water and an impeller 40 b mounted on shaft 16 and including a circumferentially spaced series of curved vanes 40 c . It will be understood that when the impeller is driven by shaft 16 , liquid is drawn in through inlet 40 a from the liquid source, passes between the vanes of the impeller, and is thereafter thrown outward by centrifugal force for passage through pump outlet 40 d and into conduit 42 .
Conduit 42 extends from pump outlet 40 d to the inlet opening 12 g in the cooling chamber of the combustor so that cooling liquid from pump 40 is conveyed by conduit 42 to annular cooling chamber 24 .
During steady state operation of the gas turbine engine assembly, fuel and air id delivered to the combustor via conduits 30 and 28 respectively for combustion in the combustor to form flame front 32 within central combustion chamber 22 of the combustor, the combustion products from the combustion chamber are delivered via conduit 38 to the inlet of the turbine to drive the turbine, and the turbine shaft drives pump 40 and compressors 14 and 18 to provide continuous delivery of fuel and air to the combustor and to further provide delivery of a cooling fluid to annular cooling chamber 24 of the combustor via conduit 42 .
The behavior of the cooling fluid in annular cooling chamber 24 will vary depending upon the pressure and temperature at which fluid id delivered to the cooling chamber. For example, and as shown in FIGS. 1 and 2, water may be delivered to cooling chamber 24 in a steady state manner at 30 bars and 300° Kelvin, in which case, assuming combustion chamber 22 is operating at 25 bars and 2,300° Kelvin at flame front 32 with an arbitrary combustion rate of 150 kilowatts, the gas turbine engine assembly can be sized such that water can be maintained in the lower end of the annular combustion chamber, below lowermost aperture 12 e , to form annular water bath 44 . Water bath 44 absorbs energy from the combustion products within the combustion chamber through inner wall 12 d with the result that the water is converted to a vapor or steam phase 46 which forms in cooling chamber 24 above bath 44 and thereafter passes through apertures 12 e and into combustion chamber 22 where it mixes with the combustion products within the combustion chamber and passes with the combustion products through hood 36 and conduit 38 to the inlet of the turbine to drive the turbine.
The energy absorbed from the flame front by the annular body of water 44 (representing the energy required to change the water from a liquid to a gas phase) together with the cooling effect of the vapor as it passes through apertures 12 e and joins the combustion products within the combustion chamber, has the effect of reducing the temperature of the combustion products leaving the combustor through aperture 12 f to approximately 1140° kelvin, This temperature is low enough to ensure that the combustor does not suffer thermal failure and is further low enough to ensure that there is no significant NO x formation within the combustor.
The modified gas turbine engine assembly shown in FIG. 3 is generally similar to the assembly shown in FIGS. 1 and 2 with the exception that the assembly in FIG. 3 further includes a heat exchanger 50 positioned in conduit 42 and arranged to receive the discharge from outlet 10 b of the turbine through conduit 52 and place the discharge products from the gas turbine in heat exchange relation to the cooling fluid flowing through conduit 42 , whereby to add energy to the fluid so that the fluid arriving at inlet 12 g of the combustor has a higher energy content than the fluid leaving pump 40 .
As with the assembly of FIGS. 1 and 2, the nature and behavior of the fluid within cooling chamber 24 may be selectively varied by selective variation of the temperature and pressure under which the cooling fluid is delivered to the cooling chamber through conduit 42 . For example, water may be delivered to heat exchanger 50 in a steady state manner at 100 bars and 300° Kelvin, and thermal energy may ideally be added to the water so that it enters conduit 42 b , for delivery to cooling chamber 24 at 100 bars and 584° Kelvin. When the water enters inlet 12 g at 100 bars and 584° Kelvin, cooling chamber 24 is totally filled with water, and again assuming combustion chamber 22 is operating at 25 bars and 2300° Kelvin at flame front 32 with an arbitrary combustion rate of 150 kilowatts, the gas turbine engine assembly can be sized such that thermal energy is absorbed through wall 12 d from flame front 32 so as to cool the flame front and raise the temperature of the water. In this embodiment, with the given parameters, water passes through apertures 12 e in a still liquid form and undergoes a phase change immediately upon entering combustion chamber 22 whereby to extract further energy from the flame front by virtue of the energy required to change the water to a gas or vapor, whereafter the gas or vapor passes out of the combustion chamber through discharge opening 12 f for delivery with the combustion products to the inlet of the gas turbine. As with the assembly shown in FIGS. 1 and 2, the combined effect of the energy absorbed by the water residing in annular cooling chamber 24 , together with the energy required to accomplish the phase change of the water as it passes through openings 12 e and encounters the flame front, has the effect of lowering the combustor temperature to a point (for example, 1140° Kelvin at discharge aperture 12 f ) where thermal failure of the combustor is prevented and not significant NO x forms.
It should be understood that, in the embodiment of FIG. 3, the cooling flow rate can be increased such that coolant can pass through apertures 12 e in liquid form whereafter some of the liquid can pass to a vapor and some of the liquid can flow downwardly by gravity to absorb energy and remove fuel contaminants whereafter the liquid can be removed through a drain port 12 i . For example, the liquid flowing outwardly through drain port 12 i can be at 490° kelvin and 25 bars. Supplying excess liquid to the combustor and allowing the excess liquid to flow downwardly in the combustor for discharge through drainage port 12 i has a washing down effect and specifically, and depending upon the fuel employed, removes fuel bound metals such as lead, nickel and vanadium, minerals such as calcium and sulphur, and combustion products such as coke, ash and soot.
The embodiment of the gas turbine engine assembly seen in FIG. 4 is similar to the embodiment seen in FIG. 3 with the exception that apparatus 54 is interposed in conduit 42 in a manner which allows apparatus 54 to receive the cooling fluid output of heat exchanger 50 through conduit 42 c before the cooling fluid is delivered to cooling chamber 24 through conduit 42 b . Apparatus 54 may, for example, comprise a boiler fired by a separate source of energy, such as gas, so that apparatus 54 serves to add further energy to the fluid flowing through conduit 42 .
As with the embodiment of FIGS. 1 and 2 and the embodiment of FIG. 3, the nature and behavior of the fluid in cooling chamber 24 may be selectively modified by selectively varying parameters of the system. For example, the pump parameters may be chosen such that water leaves the pump at 330 bars and 300° Kelvin; heat exchanger 50 parameters may be chose such that water leaving the heat exchanger is at 300 bars and 584° Kelvin; and the boiler parameters may be chosen such that superheated steam or water vapor leaves boiler 54 and thereafter enters cooling chamber 24 through inlet 12 g at 673° Kelvin and 300 bars. With these parameters, cooling chamber 24 is totally filled with water vapor or gas, and as the vapor or gas resides in the cooling chamber 24 , it absorbs energy from the flame front through inner wall 12 d whereby to raise the temperature of the vapor or gas in the cooling chamber, whereafter the gas or superheated vapor passes through apertures 12 e to join the flame front of r passage out of the discharge aperture 12 f and passage with the combustion products to the inlet of the turbine.
As with the embodiment of FIGS. 1 and 2, and the embodiment of FIG. 3, the combined action of the energy absorbed by the vapor residing in cooling chamber 24 and the cooling effect of the vapor as it passes through apertures 12 e to joint the flame front, has the effect of reducing the combustor temperature to a temperature below the thermal failure temperature of the combustor and below the temperature at which any significant NO x formation takes place. As with the embodiment of FIGS. 1 and 2, and the embodiment of FIG. 3, the temperature of the combustion products leaving the combustion chamber through apertures 12 f may be controlled to approximately 1140° Kelvin, assuming combustion chamber 22 is operating a 25 bars and 2300° Kelvin at flame front 32 , with an arbitrary combustion rate of 150 kilowatts.
In each of the invention embodiments, it will be seen that the cooling the combustor is accomplished without the use of cooling air. It will further be seen that, in each case, energy is absorbed from the flame front in a two-stage process with the first stage comprising the absorption of energy by the cooling fluid in chamber 24 through inner wall 12 d and the second stage comprising the further cooling of the flame front as the fluid in cooling chamber 24 passes through apertures 12 e to joint the flame front.
The invention will be seen to provide a simple and efficient means of maintaining the combustor below the temperature at which thermal failure and NO x formation occurs without substantially interfering with flame ignition or maintenance, and with out elevating the carbon monoxide, level unburned hydrocarbon, or fuel consumption of the engine. Specifically, the invention methodology, level requiring only a relatively low energy consumption pump to provide the cooling needs of the combustor as opposed to the relatively high energy air compressors of the prior art, has the effect of increasing the net turbine work output since the energy required to produce the required cooling effect is significantly reduced as compared to systems in which the cooling is achieved utilizing air or a combination of air, water injection and/or steam injection.
Whereas preferred embodiments of the invention have been illustrated and described in detail, it will be apparent that various changes may be made in the disclosed embodiments without departing from the scope or spirit of the invention. For example, although the invention has been described with reference to a liquid or a gas utilized as the cooling substance, the cooling substance may also in certain applications, comprise a suitable alkali metal or Newtonian fluid, and the term substance as used in the claims is intended to include a liquid, gas alkali metal, or Newtonian fluid. | A gas turbine engine assembly including improved means for cooling the combustor to preclude thermal failure of the combustor and to preclude NO x formation. The system includes a liquid pump driven by the turbine shaft and supplying a cooling fluid to an annular chamber defined around the central combustion chamber of the combustor. The cooling fluid is thereby placed in heat exchange relation to the combustor to absorb heat from the combustion products within the combustion chamber and convert the fluid to a relatively higher energy condition, whereafter the fluid in its high energy condition is injected into the combustion chamber for mixture with the combustion products and delivery with the combustion products to the turbine inlet. The cooling liquid may totally fill the annular cooling chamber around the combustion chamber or may partially fill tie cooling chamber, or the cooling fluid arriving at the cooling chamber may already be in a gaseous state so that the cooling chamber is totally filled with a vapor. | 5 |
FIELD OF THE INVENTION
[0001] The present invention relates to preparation of novel intermediate and novel process for the preparation of (2R)-2-acetamido-N-benzyl-3-methoxypropanamide.
BACKGROUND AND PRIOR ART
[0002] The compound (2R)-2-acetamido-N-benzyl-3-methoxypropanamide of Formula-I having an international non-proprietary name Lacosamide is an anticonvulsant drug for the treatment of central nervous system disorder such as epilepsy. It is also useful in the treatment of pain particularly diabetic neuropathic pain.
[0000]
[0003] U.S. Pat. No. 5,773,475 for first time reported the preparation of Lacosamide of Formula-I by three different methods. In the first method, D-serine is esterified followed by treating the D-serine methyl ester with benzylamine to result the compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II. The compound of Formula-II is acetylated with acetic anhydride in solvent dichloromethane to give the compound (2R)-2-acetamido-N-benzyl-3-hydroxypropanamide of Formula-III. The compound of Formula-III is methylated using methyl iodide in the presence of silver oxide and solvent acetonitrile to give Lacosamide of Formula-I.
[0004] The second method describes the process, wherein D-serine is protected with benzyloxycarbonyl chloride to give N-Benzyloxycarbonyl-D-serine of Formula-IV. The compound of Formula-IV on alkylation with methyl iodide in the presence of silver oxide and solvent acetonitrile yields the compound (2R)-methyl 2-(benzyloxycarbonylamino)-3-methoxypropanoate of Formula-V, and which is purified by flash column chromatography using silica gel and methanol-chloroform eluent before the next stage. The compound of Formula-V is hydrolyzed to give (2R)-2-(benzyloxycarbonylamino)-3-methoxypropanoic acid of Formula-VI. The compound of Formula-VI is cooled to −78° C. in tetrahydrofuran and reacted with isobutyl chloroformate in presence of N-methylmorpholine followed by reaction with benzylamine to yield the compound (2R)-benzyl 1-(benzylamino)-3-methoxy-1-oxopropan-2-ylcarbamate of Formula-VII. The compound of Formula-VII on hydrogenation using palladium on carbon gives deprotected compound (2R)-2-amino-N-benzyl-3-methoxy-propanamide of Formula-VIII. The compound of Formula-VIII is acetylated using acetic anhydride in the presence of solvent pyridine to give crude Lacosamide of the Formula-I. The crude compound is purified by flash column chromatography to give pure Lacosamide.
[0005] The third method described in the patent, wherein D-serine is first acetylated to give N-acetylserine, which is taken in tetrahydrofuran and cooled to −78° C. to react with isobutyl chloroformate in the presence of N-methylmorpholine followed by reaction with benzylamine to give (2R)-2-acetamido-N-benzyl-3-hydroxypropanamide of Formula-III. The compound of Formula-III is purified by flash column chromatography and taken for alkylation with methyl iodide in the presence of silver oxide and solvent acetonitrile to give Lacosamide of Formula I. The reaction sequence of above three methods can be represented in Scheme-1.
[0000]
[0006] Another patent application U.S.2009143472, discloses the process for preparation of Lacosamide of Formula-I, wherein D-serine is treated with trimethylsilyl chloride to protect the hydroxyl group and then reacted with trityl chloride followed by deprotection of hydroxyl group to isolate the protected compound N-trityl-D-serine of Formula-IX. The compound of Formula-IX is alkylated with methyl iodide in the presence of sodium hydride and imidazole at −15 to −5° C. to get the compound O-methyl-N-trityl-D-serine of Formula-X. The compound of Formula-X is reacted with isobutyl chloroformate in presence of N-methylmorpholine and followed by reaction with benzylamine to get the compound (2R)-N-benzyl-3-methoxy-2-(tritylamino)propanamide of Formula-XI. The compound of Formula-XI on deprotection yields the compound (2R)-2-amino-N-benzyl-3-methoxypropanamide of Formula-VIII, which on acetylation with acetic anhydride in the presence of dimethylaminopyridine yields Lacosamide of Formula-I. The reaction sequence is as given in Scheme-2;
[0000]
[0007] Another U.S. patent application U.S.2008027137 describes the preparation of Lacosamide of Formula-I, wherein N-protected D-serine is O-methylated with either using dimethyl sulfate in presence of phase-transfer catalyst and sodium hydroxide or with butyllithium and dimethyl sulfate to get the compound (2R)-2-(tert-butoxycarbonylamino)-3-methoxypropanoic acid of Formula-XII. The compound of Formula-XII is reacted with benzylamine as per the process disclosed earlier to get the compound (2R)-tert-butyl 1-(benzylamino)-3-methoxy-1-oxopropan-2-ylcarbamate of Formula-XIII. Deprotection of the compound of Formula-XIII with hydrochloric acid yields the compound (2R)-2-amino-N-benzyl-3-methoxy-propanamide of Formula-VIII, which on acetylation yields the compound Lacosamide of Formula-I. The reaction sequence is as given in Scheme-3.
[0000]
[0008] Another method for the preparation of Lacosamide of Formula-I was described in the Journal Bioorganic & Medicinal Chemistry, 16(19), 8968-8975 (2008), wherein D-serine methyl ester is treated with diethoxytriphenylphosphorane to give 9:1 mixture of (R)-aziridine-2-carboxylic acid methyl and ethyl ester of Formula-XIV. The mixture of compound of Formula-XIV on acetylation with acetic anhydride in the presence of triethylamine and dimethylaminopyridine gives a mixture of (R)-1-acetylaziridine-2-carboxylic acid methyl and ethyl ester of Formula-XV. The mixture of compound of Formula-XV is treated with methanol in the presence of borontrifluoride etherate BF 3 .Et 2 O to give a mixture of (2R)-2-acetamido-3-methoxypropanic acid methyl and ethyl ester of Formula-XVI. The compound of Formula-XVI on hydrolysis with lithium hydroxide yields the compound (2R)-2-acetamido-3-methoxypropanoic acid of Formula- XVII; which on reaction with benzylamine in presence of tetrahydrofuran and 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride followed by purification of the product using flash column chromatography (10:90 MeOH/CHCl 3 ) yields compound Lacosamide of Formula-I. The reaction sequence is as given in Scheme-4;
[0000]
[0009] The drawbacks of the above described processes are:
i. Use of expensive D-serine or its derivatives as starting material; ii. O-methylation involves the use of methyl iodide and silver oxide, which is expensive; iii. Lower temperature required to carry out the amide formation reaction; iv. The purification using flash column chromatography to purify the intermediates and the final compounds renders the process industrially unviable.
[0014] It is therefore required to develop an alternative and improved process for the preparation of Lacosamide which overcomes the problems associated with the processes known in the art.
[0015] The present inventors ameliorates the problems of the prior art processes by using cost effective, naturally occurring starting material and avoiding the use of Flash column chromatography for the purification of product Lacosamide of Formula-I.
OBJECTIVES OF THE INVENTION
[0016] The main objective of the present invention is to prepare highly pure compound (2R)-2-acetamido-N-benzyl-3-methoxypropanamide of Formula-I with an industrially useful cost effective process.
[0017] Another objective of the present invention is to prepare novel intermediate compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX;
[0018] Yet another objective of the present invention is to prepare novel intermediate compound (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX.
SUMMARY OF THE INVENTION
[0019] Accordingly, the present invention provides a process to prepare (R)-N-Benzyl-2-acetamido-3-methoxypropanamide of Formula-I;
[0000]
[0020] comprising the steps of;
[0021] i. reacting (2S)-2-bromo-3-hydroxypropanoic acid of Formula-XVIII;
[0000]
[0022] with benzylamine in presence of a base and an activator to get (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX;
[0000]
[0023] ii. reacting the compound of Formula-XIX with sodium azide in presence of polar aprotic solvent to get (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX;
[0000]
[0024] iii. hydrogenating the compound of Formula-XX using catalyst in presence of solvent to get the compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II;
[0000]
[0025] iv. protecting the compound of Formula-II with di-tert-butyl dicarbonate to get the compound tent-butyl [(R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl] carbamate of Formula-XXI;
[0000]
[0026] v. alkylating the hydroxyl group of the compound of Formula-XXI to isolate the compound (2R)-2-amino-N-benzyl-3-methoxypropanamide of Formula-VIII;
[0000]
[0027] vi. acetylating the compound of Formula-VIII in presence of a base and solvent to get (2R)-2-acetamido-N-benzyl-3-methoxypropanamide of Formula-I.
[0028] In an aspect, the process according to the present invention provides a novel intermediate compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX;
[0000]
[0029] In another aspect, the process of the present invention discloses a novel intermediate compound (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX;
[0000]
DESCRIPTION OF THE INVENTION
[0030] The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.
[0031] The present invention provides an improved process to prepare the compound (2R)-2-acetamido-N-benzyl-3-methoxypropanamide of Formula-I. Further the present invention overcomes the inherent difficulties that exist in prior art when it is desirable to produce the product on commercial scale.
[0000]
[0032] In one of the embodiments of the present invention, the compound (2S)-2-bromo-3-hydroxypropanoic acid of Formula-XVIII is subjected to react with benzylamine in presence of a base and an activator under mixed anhydride coupling condition to get (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX. The mixed anhydride coupling reaction conditions as described by Anderson, et al., in JACS, 1967, 89, 5012-5017, the contents of which are incorporated herein by reference. The activators used to activate the carbonyl group are selected from optionally substituted alkyl or aryl chloroformates such as methyl chloroformate, ethyl chloroformate, isobutyl chloroformate, phenyl chloroformate, pivolyl chloride, 1,1-carbonyldiimidazole, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N,N′-dicyclohexylcarbodiimide. The preferred activator used is alkyl chloroformate selected from methyl chloroformate, ethyl chloroformate and isobutyl chloroformate wherein the most preferred activator used is isobutyl chloroformate. The base used in the reaction is selected from N-methylmorpholine, pyridine, N,N-diisopropylethylamine and triethylamine wherein the preferred base used is N-methylmorpholine. The reaction is carried out in the presence of solvent at temperature in the range of −20° C. to 30° C. The solvent used for the reaction is selected from dichloromethane, ethyl acetate, toluene and tetrahydrofuran. The preferred solvent used for the reaction is ethyl acetate. Accordingly, the compound (2S)-2-bromo-3-hydroxypropanoic acid of Formula-XVIII is taken in ethyl acetate and the isobutyl chloroformate is charged at 20-30° C. Stirred and cooled the reaction mixture to −20° C. Maintaining the temperature at −20° C. charged base N-methylmorpholine and benzylamine to the reaction mass. The reaction is maintained between −20° C. to 30° C. for 4-10 hours. After completion of the reaction, concentrated the reaction mass under reduced pressure, maintaining temperature below 40° C. to get the residual mass. Charged non polar solvent to isolate the compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX. The non polar solvent used for isolation of the compound is selected from hexane, heptane and diisopropyl ether, wherein the preferred non polar solvent used is diisopropyl ether. Stirred and filtered the separated solid product, washed with water and dried to get the compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX.
[0033] The starting compound (2S)-2-bromo-3-hydroxypropanoic acid of Formula-XVIII used for the present invention is prepared as per the process disclosed in Organic Synthesis, Coll. Vol. 10, p. 401 (2004).
[0034] In another embodiment of the present invention, the benzyl aminated compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX is reacted with sodium azide in presence of polar aprotic solvent at a temperature in the range of 30-70° C. to get the compound (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX. The preferred temperature range for the reaction is 50-70° C. The polar aprotic solvent used for the reaction is selected from N,N-dimethylformamide, acetonitrile, N-methylpyrrolidone, dimethyl sulfoxide, and N,N-dimethylacetamide, wherein the preferred solvent used for the reaction is N,N-dimethylformamide. Accordingly, the compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX is taken in the solvent N, N-dimethylformamide and sodium azide is charged. Stirred and raised the reaction temperature up to 50° C. and maintained the reaction mass at 50-70° C. for 3 to 6 hours. The reaction is cooled and diluent ethyl acetate is added to the reaction mass. The pH of the reaction mass is adjusted to 9-9.5 with the help of dilute solution of base. The base used for the pH adjustment is selected from aqueous ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate and potassium carbonate, wherein the preferred base used for the pH adjustment is sodium bicarbonate. The reaction is further diluted with water and separated the organic layer. Extracted the aqueous layer further with ethyl acetate and mixed with the organic layer. Concentrated the organic layer under reduced pressure below 40-45° C. to get the residual mass of azido compound (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX.
[0035] The advantage of the present invention is that, during the azido reaction the complete inversion of the stereo centre from (S) to (R) is achieved at 2 position of the benzylaminated compound. The compound disclosed herein can be enantiomerically pure and one enantiomer substantially free from other enantiomer can be prepared.
[0036] In another embodiment of the present invention, the compound (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX is hydrogenated in presence of polar solvent and catalyst to get the amino compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II. The polar solvent used is selected from C 1 -C 4 linear or branched alcohol and esters selected from methanol, ethanol, propanol, isopropyl alcohol, n-butanol, ethyl acetate, propyl acetate, isopropyl acetate, isoamyl acetate and butyl acetate. The preferred solvent used for hydrogenation is selected from ethyl acetate, propyl acetate, isopropyl acetate, isoamyl acetate and butyl acetate, wherein the most preferred solvent used for hydrogenation reaction is ethyl acetate. The catalyst used for the hydrogenation reaction is 5% palladium on carbon and 10% palladium on carbon. The amino compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II, after the reaction is isolated from the reaction mass by filtration, concentration and purification using aliphatic acetate solvent selected from ethyl acetate, propyl acetate, isopropyl acetate, isoamyl acetate and butyl acetate either single or mixture thereof. The preferred solvent used for purification is ethyl acetate.
[0037] In another embodiment of the present invention, the benzylaminated compound (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX is reacted with sodium azide in presence of polar aprotic solvent at a temperature in the range of 30-70° C. The reaction mixture without isolating the intermediate is subjected to hydrogenation in presence of polar solvent and catalyst results in the compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II. The preferred temperature range for the sodium azide reaction is 50-70° C. The polar aprotic solvent used for the reaction is selected from N,N-dimethylformamide, N-methylpyrrolidone, acetonitrile, dimethyl sulfoxide, and N,N-dimethylacetamide, wherein the preferred solvent used for the reaction is N,N-dimethylformamide. The catalyst used for the hydrogenation reaction is 5% palladium on carbon or 10% palladium on carbon. The polar solvent used is selected from C 1 -C 4 aliphatic esters selected from ethyl acetate, propyl acetate, isopropyl acetate, isoamyl acetate and butyl acetate. The preferred solvent used for hydrogenation is ethyl acetate.
[0038] In yet another embodiment of the present invention the amino compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II is reacted with di-tent-butyl dicarbonate in an organic solvent in presence of base at temperature in the range of 0° C.-40° C. to get the compound tent-butyl [(R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]carbamate of Formula-XXI. The solvent used for the reaction is selected from methanol, ethanol, propanol, isopropyl alcohol, n-butanol, ethyl acetate, propyl acetate, isopropyl acetate, isoamyl acetate and butyl acetate, dichloromethane and dichloroethane. The preferred solvent used for the reaction is selected from ethyl acetate, propyl acetate, isopropyl acetate, isoamyl acetate and butyl acetate, wherein the most preferred solvent used is ethyl acetate. The base used in the reaction is selected from triethylamine, pyridine, N-methylmorpholine, N-methylpyrrolidone, N-methylpiperidine and dimethylaminopyridine, wherein the preferred base used is triethylamine.
[0039] Accordingly the compound (2R)-2-amino-N-benzyl-3-hydroxypropanamide of Formula-II is charged in solvent and the base is added at 0° C. Maintaining the temperature at 0°-10° C. the compound di-tert-butyl dicarbonate is added and the reaction is continued at 0° C.-30° C. The reaction is carried out for 2-8 hours, concentrated under reduced pressure below 45° C. to get the residual mass of tert-butyl [(R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]carbamate of Formula-XXI. The residual mass tert-butyl [(R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]-carbamate of Formula-XXI obtained is isolated using non-polar solvent selected from hexane, heptane, cyclohexane, toluene and xylene, wherein the preferred solvent used for isolation of the compound is cyclohexane.
[0040] In another embodiment of the present invention, the O-alkylation of the compound tert-butyl [(R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]carbamate of Formula-XXI is performed by means of an alkylating agent in presence of base, a catalyst and an organic solvent. The alkylating agent used for the purpose of this invention is selected from dimethyl sulfate and trimethylsilyldiazomethane. The base used in the reaction is an aqueous solution of the base selected from metal hydrides, metal hydroxides and metal carbonates of sodium, potassium, lithium and calcium. The preferred base used is aqueous solution of sodium hydroxide. The organic solvent used for the reaction is selected form dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, and toluene, wherein the preferred solvent used is dichloromethane. The catalyst used for the methylation reaction is a phase transfer catalyst selected from tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltriethylammonium chloride and benzyltriethylammonium bromide. The preferred phase transfer catalyst used is tetrabutylammonium bromide. The methylation reaction is carried out at a temperature in the range of −15° C. to 15° C., wherein the preferred temperature range for the methylation reaction is −10° C. to 0° C.
[0041] Accordingly to a solution of the compound tert-butyl [(R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]carbamate of Formula-XXI in dichloromethane, charged the phase transfer catalyst and cooled the reaction mass to −10° C. and charged dilute solution of sodium hydroxide. Maintaining the temperature at −10° C.-0° C. charged dimethyl sulfate and maintained the reaction under stirring for 3-5 hours. Charged water at the end of the reaction, stirred, separated the organic layer and extracted the aqueous layer with the dichloromethane. Combined the organic layer and acidified with concentrated hydrochloric acid. Charged water to the clear solution and stirred. Separated the aqueous layer and extracted the organic layer further with water. Combined the entire aqueous layer and adjusted the pH to 12 with aqueous sodium hydroxide solution. Extracted the aqueous layer with dichloromethane and separated the organic layer. Extracted the aqueous layer further with dichloromethane to ensure the complete extraction of the desired product. The organic layer is washed and concentrated to isolate the compound (2R)-2-amino-N-benzyl-3-methoxypropanamide of Formula-VIII.
[0042] The compound of (2R)-2-amino-N-benzyl-3-methoxypropanamide of Formula-VIII is acetylated further using acetic anhydride in presence of base and solvent to isolate the crude compound (2R)-2-acetamido-N-benzyl-3-methoxypropanamide of Formula-I [Lacosamide]. The base used is selected from pyridine, N-methylmorpholine, triethylamine, N-methylpyrrolidine and N-methylpiperidine, wherein the preferred base used is triethylamine. The solvent used is selected from acetonitrile dichloromethane, ethyl acetate, cyclohexane and tetrahydrofuran or mixture thereof. The preferred solvent used for acetylation is ethyl acetate and cyclohexane either single or mixture thereof. The crude Lacosamide is further slurried in diethyl ether to isolate pure Lacosamide.
[0043] The reaction sequence of the present invention can be represented as given in scheme-5 below;
[0000]
[0044] The process according to the present invention provides a novel intermediate of (2S)-N-benzyl-2-bromo-3-hydroxypropanamide of Formula-XIX;
[0000]
[0045] Also disclosed is a novel intermediate (2R)-2-azido-N-benzyl-3-hydroxypropanamide of Formula-XX which forms part of an embodiment.
[0000]
[0046] Certain specific aspects and embodiments of the present invention is further illustrated in detail with reference to the following examples, which are provided solely for the purpose of illustration and are not to be construed as limiting the scope of the invention in any manner.
EXAMPLES
Example-1
Preparation of (2S)-2-bromo-3-Hydroxypropanoic Acid
[0047] To a solution of 100 g L-Serine and 385.23 g potassium bromide in 750 ml of water, aqueous solution of hydrobromic acid (47%, 238 ml) is added at 25-30° C. and the mixture is cooled under stirring to −15° C. to -12° C. Nitrogen is bubbled through the solution and slowly added, 80.87 g sodium nitrite in small lots within 2-2.5 hours. The solution is then allowed to warm to 0° C. and nitrogen purging is stopped. The reaction mixture is stirred for 3-4 hours at 0-10° C. Excess nitrogen oxides are removed by bubbling nitrogen through the solution for 1 hour. The aqueous layer is extracted with ethyl acetate (1×1000 ml, 2×500 ml). The combined organic extracts dried over anhydrous sodium sulphate and concentrated under reduced pressure at 35-40° C. to obtain pale yellow or green oil of (2S)-2-bromo-3-hydroxypropanoic acid.
[0048] Yield=138.0 gms.
[0049] % Yield=85.80%.
Example-2
Preparation of (2S)-N-benzyl-2-bromo-3-hydroxypropanamide
[0050] To a solution of (2.9-2-bromo-3-hydroxypropanoic acid (138.0 g) in ethyl acetate (966.0 ml) isobutyl chloroformate (133.85 g) was added at 20-25° C. and cooled the reaction mass to −12° C. To this reaction mixture under nitrogen atmosphere the solution of N-methylmorpholine (107.23 g) and benzylamine (96.26 g) in ethyl acetate (178.0 ml) was added slowly maintaining temperature at −12° C. to −5° C. over a period of 1.0 hour. Maintained the reaction mixture at −5° to 0° C. for 30 minutes and raised the temperature slowly to 25-30° C. and maintained further for 1 hour. Reaction mass was concentrated ,under reduced pressure at 30° C. to 35° C. till one volume of the reaction mass remains in the reaction vessel. To the reaction mass was charged diisopropyl ether (300 ml) and distilled under reduced pressure till one volume of the reaction mass remains in the reaction vessel. To the reaction mass was charged diisopropyl ether (400 ml) and stirred the reaction mass for 30 minutes at 25-30° C. followed by addition of DM water (500 ml) and stirred for 30 minutes at 25-30° C. Filtered the solid separated and washed the cake with diisopropyl ether (2×100 ml) followed by DM water (500 ml) to get (25)-N-benzyl-2-bromo-3-hydroxypropanamide. Dried the compound at 50-55° C. till constant weight.
[0051] Yield=140 g.
[0052] % Yield=66.40%.
[0053] 1 H-NMR (400 MHz, DMSO-d 6 ) δ: 3.62 (1H, m), 3.83 (1H, m), 4.3 (3H, m), 5.42 (1H, D 2 O exchangeable), 7.27 (5H, m), 8.81 (1H, D 2 O exchangeable)
[0054] 13 C-NMR (400 MHz, DMSO-d 6 ) δ: 42.799, 48.606, 63.113, 127.394, 127.624, 128.819, 139.310, 168.038
[0055] Mass: (M, M+2)=257.9 & 259.9 (1:1)
Example-3
Preparation of (2R)-2-azido-N-benzyl-3-hydroxypropanamide
[0056] To a reaction flask was charged (2S)-N-benzyl-2-bromo-3-hydroxypropanamide (80.0 g) and sodium azide (30.23 g) in N,N-dimethylformamide (480 ml) and raised the temperature to 50-55° C. and maintained for 4-5 hours. Stopped heating and cooled the reaction mixture to 20-25° C. and charged DM water (400 ml), adjusted pH of the reaction mixture to 9-9.5 using 5% NaHCO 3 solution. Extracted the reaction mass with ethyl acetate (1× 800 ml, 2×280 ml). Separated the organic layer and combined all ethyl acetate layers, washed with saturated ammonium chloride solution (2×240 ml). Concentrated the solvent ethyl acetate under reduced pressure to get oily compound of (2R)-2-azido-N-benzyl-3 -hydroxypropanamide.
[0057] Yield=68.0 gms of oil.
[0058] % Yield=99.62%
[0059] 1 H-NMR (400 MHz, CDCl 3 ) δ: 3.33 (1H, D 2 O exchangeable), 3.94-4.01 (2H, m), 4.12 (1H, t), 4.44 (2H, m), 6.93 (1H, s, D 2 O exchangeable), 7.25-7.36 (5H, m) 13 C-NMR (400 MHz, CDCl 3 ) δ: 43.62, 63.3, 64.67, 127.8, 127.88, 128.93, 137.32, 168.14 Mass: (M+)=221
Example-4
Preparation of (2R)-2-amino-N-benzyl-3-hydroxypropanamide
[0060] In an autoclave charged (2R)-2-azido-N-benzyl-3-hydroxypropanamide (68.0 gms) in ethyl acetate (680 ml). Charged catalyst 5% Pd-C (6.85 gms) and closed the autoclave. Applied 3.8 kg Hydrogen pressure maintaining temperature at 25-30° C. and maintained the reaction mixture at 25-30° C. for 1.0 hour. After completion of the reaction, released Hydrogen pressure and flushed the autoclave with Nitrogen gas. Filtered the reaction mass through hyflo bed and washed hyflo bed with ethyl acetate. Concentrated filtrate under reduced pressure at 30-35° C. till two volumes of ethyl acetate remains in the reaction mixture. Removed vacuum and cooled the reaction mass to 0-5° C. and maintained for 2.0 hours. The reaction mass was filtered and washed with cold ethyl .acetate (2×40 ml). Dried the product (2R)-2-amino-N-benzyl-3-hydroxypropanamide under vacuum at 25-30° C. till constant weight.
[0061] Yield=36.5 gms.
[0062] % Yield=60.86%.
Example-5
Preparation of (2R)-2-amino-N-benzyl-3-hydroxypropanamide
[0063] To a reaction flask charged (2S)-N-benzyl-2-bromo-3-hydroxypropanamide (80.0 gms) and sodium azide (30.23 gms) in N,N-dimethylformamide (480 ml), stirred and raised the temperature to 50-55° C. and maintained for 4-5 hours. Stopped heating and cooled the reaction mixture to 20-25° C., charged DM water (400 ml), adjusted pH of the reaction mixture to 9-9.5 using 5% NaHCO 3 solution. Extracted the reaction mixture with ethyl acetate (1×800 ml, 2×280 ml) separated the organic layer and combined all ethyl acetate layers, washed with saturated ammonium chloride solution (2×240 ml). The ethyl acetate layer was taken for hydrogenation to 2 lit autoclave. Charged ethyl acetate layer and 5% Pd-C (6.85 gms) was added and closed the autoclave. Applied 3.8 kg Hydrogen pressure maintaining temperature at 25-30° C. and maintained the reaction mixture at 25-30° C. for 1.0 hour. After completion of the reaction released Hydrogen pressure and flushed the autoclave with Nitrogen gas. Filtered the reaction mass through hyflo bed and washed hyflo bed with ethyl acetate. Concentrated filtrate under reduced pressure at 30-35° C. till two volumes of ethyl acetate remains in the reaction mixture. Removed vacuum and cooled the reaction mass to 0-5° C. and maintained for 2.0 hours. The reaction mass was filtered and washed with cold ethyl acetate (2×40 ml). Dried the product (2R)-2-amino-N-benzyl-3-hydroxypropanamide under vacuum at 25-30° C. till constant weight.
[0064] Yield=36.5 gms.
[0065] % yield=60.63%.
Example-6
Preparation of tert-butyl [(1R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]carbamate
[0066] To a solution of (2R)-2-amino-N-benzyl-3-hydroxypropanamide (34.0 gms) in ethyl acetate (170 ml), charged di-tert-butyl dicarbonate (45.89 gms) and stirred for 1.0 hour at 25-30° C. Charged triethylamine (1.77 gms) and stirred further for 1 hr at 25-30° C. After completion of reaction, concentrated the reaction mass under reduced pressure at 30-35° C. till 1 volume of ethyl acetate remained inside the reaction mass. Removed vacuum and charged cyclohexane (102 ml) and concentrated under reduced pressure till one volume of the solvent remained in the reaction mass. Charged cyclohexane (272 ml) and stirred at 25-30° C. for 1 hr. Filtered the reaction mass and washed with fresh cyclohexane. Dried the product Tert-butyl [(1R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl] carbamate at 50-55° C. till constant weight.
[0067] Yield=47.2 gms
[0068] Yield=91.65%
Example-7
Preparation of (2R)-2-amino-N-benzyl-3-methoxypropanamide
[0069] In a reaction flask charged tert-butyl [(1R)-2-(benzylamino)-1-(hydroxymethyl)-2-oxoethyl]carbamate (110.0 gms) and tetrabutylammonium bromide (18.07 gms) in solvent -dichloromethane (550 ml), stirred and cooled to −10° C. Charged aqueous solution of sodium hydroxide (75.0 gms in 195 ml of DM water) maintaining temperature at −10° C. to −5° C. Charged slowly within 1 hour, dimethyl sulfate (141.4 gms) maintaining temperature at −10° C. to −5° C. and maintained the reaction mass at −10° C. to −5° C. for 3.5 to 4.5 hrs. After completion of the reaction, charged DM water (550 ml) and stirred for 15 minutes at 25-30° C. Separated the organic layer and charged in the reaction flask. Charged conc. Hydrochloric acid (440 ml) within 15 min and maintained the reaction mixture at 25-30° C. for 1-2 hours. After completion of 2 hours charged DM water (330 ml) and stirred for 20-25 minutes. Separated the organic layer and washed with DM water (330 ml). Combined both aqueous layers and cooled to 15-20° C. to adjust pH of the solution to 13-14 with the help of 50% sodium hydroxide solution. Extracted the aqueous layer with dichloromethane (1×550 ml, 2×330 ml). Combined all dichloromethane layers and washed with DM water and stirred at 25-30° C. for 10-15minutes. Charcoalised dichloromethane layer at 25-30° C. for 30 minutes, filtered and washed the hyflow bed with dichloromethane (2×110 ml). Concentrated the filtrate under reduced pressure below 40° C. and degas under vacuum at 35-40° C. for 3-4hrs to get oily mass of (2R)-2-Amino-N-benzyl-3-methoxypropanamide.
[0070] Yield=70.6 gms
[0071] % Yield=90.71%.
Example-8
Preparation of (2R)-2-acetamido-N-benzyl-3-methoxypropanamide (Lacoasmide)
[0072] To a solution of (2R)-2-Amino-N-benzyl-3-methoxypropanamide (60.0 gms) and triethylamine (7.29 gms) in cyclohexane (600 ml) charged ethyl acetate (540 ml) and added acetic anhydride (35.29 gms) slowly maintaining the temperature at 25-30° C. in 15-20 minutes. Raised the temperature of the reaction mass to 35-40° C. and maintained for 4 hours. After completion of the reaction the reaction mass was cooled to 0 to 5° C. within 1 hour and maintained for 1.5 hours. Filtered the reaction mass at 0-5° C. and washed with cooled 1:1 mixture of ethyl acetate: cyclohexane (2×120 ml). The wet solid was taken in diethyl ether (612 ml) and stirred for 6 hours at 20-25° C. Filtered the product (2R)-2-acetamido-N-benzyl-3-methoxypropanamide and washed with diethyl ether and dried at 50-55° C. till constant weight.
[0073] Yield=53.48 gms,
[0074] % Yield=74.16%. | The present invention discloses novel process for the preparation of (2R)-2-acetamido-N-benzyl-3-methoxypropanamide of Formula I involving novel intermediates of Formula-XIX and Formula-XX. | 2 |
RELATED APPLICATIONS
This application claims priority to and benefit of U.S. Provisional Application No. 61/134,948 filed Jul. 16, 2008, the disclosure of which is incorporated herein for all purposes.
BACKGROUND OF THE INVENTION
Background of the Invention
The term silicone resin has been applied both to and misapplied to a variety of materials over time. Silicone resins as used herein refer to a series of products, which include at least two silicone backbones that are joined by a “crosslinking group”. The number of crosslinking groups that are present as a percentage of the total molecular weight will determine the properties of the resulting polymer.
If there are no crosslinking groups; the polymer can freely rotate and consequently is an oily liquid. If a few crosslinking groups are introduced, the ability to rotate is slightly restricted and the oily material becomes “rubbery”. The rubbery material should be referred to as an elastomer. The properties are more like a rubber band than plastic. As the percentage of crosslinking increases still the molecule becomes rigid. This class of compounds is a resins. If you hit the film with a hammer and it shatters it is a resin, if it bounces it is an elastomer and if it squirts out is a silicone fluid.
The difficulty in determining if a product is a fluid an elastomer or resin occurs for products that lie between the classifications. Specifically, when does an elastomer become a resin? While this exact point is of academic interest it does not have any practical significance to the present invention.
There are a number of classes of resin compounds differing in the nature of the crosslinker. One class is the so called “Q resins”.
The oxygen that needs another bond connects to another polymer as shown:
The crosslinking group is —O—. This type of resin is disclosed in U.S. Pat. No. 6,139,823, incorporated herein by reference. This type of material has a group, the so called “Q” group in which a Si has four oxygen atoms attached. In the above case it is the group that is within the “a” subscript. This type of resin is very powdery and is rarely used without a plasticizer. This class of compounds can also dry the skin.
The next class of resin contain alkyl connecting groups.
In the case where n=1 acetylene is used as a crosslinking reactant. It is reacted with a silanic hydrogen polymer. As n is increased the reactant is an alpha omega divinyl compound.
The reaction is called hydrosilylation and provides the linking groups between the molecules. The reaction is generally run in solvent like cyclomethicone (D4 or D5 or hexamethyl disiloxane) or in volatile organic like isododecane. A catalyst generally a platinum one is used to effect the reaction. Chloroplatinic acid or Karnsteadt catalyst are preferred. The resulting material is a viscous liquid that when the solvent evaporates provides a film.
The present invention is neither crosslinked nor the result of hydrosilylation technology. Despite the teaching s to the contrary, the silicone resins of the present invention are made by esterification of a linear hydroxy silicone and a linear silicon undecylente. This is done by introducing a C11 fatty ester linkage. Not only does this solubility change, the ability to formulate solid products free from syneresis also occurs. Another unexpected benefit is that the ester moiety provides improved biodegradation of the resin making the resin “more green” and improving consumer acceptability. None of these advantageous are present in the compounds known heretofore.
Silicone resins are known, but they do not have the fatty portion shown in the present invention as —O—C(O)—(CH 2 ) 10 —. The presence of this fatty group makes the silicone resins of the present invention have more soluble in organic materials, rather than soluble in silicone materials. Of specific interest is the ability to make the resins of the present invention in esters and triglycerides, rather than cyclomethicone.
U.S. Patent Application 20070196309, incorporated herein by reference, discloses “Resins of the present invention are a class of silicone compounds which are prepared by the reaction of a di-vinyl silicone compound reacted with a terminal divinyl silanic hydrogen containing compound.
The terminal vinyl and terminal SiH on the same polymer chain eventually react with each other forming the chain. The length of the chain at which this backbiting occurs is solvent dependant. Larger molecular weight chains appear to form in hydrocarbon rather than in cyclomethicone solvents. While linear, these resins are made by the hydrosilylation and show that up until the present invention it was thought that hydrosilylation was the only method of making a resin.
U.S. Pat. No. 7,344,708 entitled Silicone polyester resins, incorporated herein by reference thaches a series of novel silicone polyesters which are prepared by crosslinking a dimethicone copolyol having at least 4 hydroxyl groups with a dimer acid. The ratio of acid groups to hydroxyl groups ranges from 0.7 to 1.4 so that a significant number of groups are reacted and a significant number of crosslink groups are achieved. This patent uses crosslinking, a feature lacking in the present materials.
The present invention also presents a series of more biodegradable polymers containing ester groups rather that the much more stable Si—C bonded materials of art. The resins of the present invention are made by classical methods (esterification) rather than silicone chemistry (hydrosilylation). The inclusion of a fatty soluble (dimer acid based) crosslinking reagent while resulting in a biodegradable ester containing destroys simultaneously destroys silicone solubility, by making the product oil soluble. The highly prized compound is one that has both a linear/linear structure and ester biodegradation.
The Invention
OBJECT OF THE INVENTION
The present invention is directed to a group of silicone polyesters.
Another objective is a process for making the silicone polyester of the present invention, which comprises reacting a specific carboxy silicone having 11 methylene groups and a hydroxy silicone to make a surprisingly organic soluble, more biodegradable film forming resin.
Another objective of the invention is a process for applying pigment to a substrate including skin, metal or glass, which comprises contacting the skin with a dispersion of pigment, a volatile solvent, and the resin of the present invention.
The resins of the current invention are useful in applications like paints, inks and coatings, and in cosmetics including but not limited to lipsticks, mascaras, transfer resistant lipsticks, powders and many other products in which silicone resins have been clearly shown to be effective.
SUMMARY OF THE INVENTION
The present invention is directed to a group of cyclic silicone polyesters and a process for making the silicone polyester of the present invention which comprises reacting a specific carboxy silicone having 11 methylene groups and a hydroxy silicone to make a surprisingly organic soluble, more biodegradable film forming resin.
The present invention is also directed to a process for applying pigment to a substrate including skin, metal or glass, which comprises contacting the skin with a dispersion of pigment, a volatile solvent, and the resin of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
One aspect of the present invention relates to a series of resins that are polyester resins made by the esterification reaction of;
(a) a carboxy silicone compound conforming to the following structure:
wherein:
x is an integer ranging from 5 to 200;
with b) a hydroxy silicone compound conforming to the following structure:
wherein:
y is an integer ranging from 5 to 200.
In a preferred embodiment the esterification reaction is conducted at a temperature of between 150 and 200° C.
In a preferred embodiment the polyester is applied to skin, or hair.
In a more preferred embodiment the polyester applied to skin, or hair additionally contains pigment.
Another aspect of the present invention relates to a series of cyclic resins that are polyester resins made that conform to the following structure;
wherein
A is
x is an integer ranging from 5 to 200;
B is:
wherein:
y is an integer ranging from 5 to 200.
z is an integer ranging from 50 to 5,000.
In a preferred embodiment x is an integer ranging between 25 and 50.
In a preferred embodiment y is an integer ranging from 25 to 50.
In a preferred embodiment x is an integer ranging between 10 and 20.
In a preferred embodiment y is an integer ranging from 10 to 20.
In a preferred embodiment x is 50.
In a preferred embodiment y is 50.
We have also found that surprisingly that the resins forming the most flexible films are obtained when so-called homo-polymers are prepared. As used herein, the term homo-polymer means that the values of “x” and “y” are within a more narrow range relative to each other. Therefore the most preferred embodiment of the polymer is when both x and y are independently integers ranging between 25 and 50.
While not wanting to be bound by any specific theory the inventors believe that the construction of a homopolymers results in a polymer that is more likely to tail bite. Tail biting is the closing of ringed structures in which the carboxy containing portion of the polymer reacts with the hydroxy terminal group on the other end. This phenomenon results in resins and is strongly directed by the size of the molecule. Put another way there are certain distances that make tail biting more likely and ring closure more probable. The preferred embodiments shown below result in the most flexible films when applied to nonporous substrates like glass.
EXAMPLES
Hydroxy Functional Silicones
Hydroxy silicones are items of commerce sold by Siltech LLC Dacula, Ga. under the Silmer® OH trade name. They conforming to the following structure:
wherein:
y is an integer ranging from 5 to 200.
The values shown below were determined by Si29 nmr, not published trade literature.
Example
y
1
5
2
10
3
25
4
30
5
50
6
200
Carboxy Functional Silicones
Carboxy silicone compound conforming to the following structure:
wherein:
x is an integer ranging from 5 to 200.
They are made by the hydrosilylation reaction of silanic hydrogen polymers conforming to the following structure:
wherein:
x is an integer ranging from 5 to 200.
with methyl undecylenate, a compound conforming to the following structure:
CH 2 ═CH—(CH 2 ) 8 —C(O)OCH 3 .
Preparation of Undecylenate Intermediates
Silanic Hydrogen Raw Materials
Silanic Hydrogen compounds are known materials available from several sources including Siltech LLC Dacula, Ga. They conform to the following structure:
wherein:
x is an integer ranging from 5 to 200.
The values shown below were determined by Si29 NMR, not published trade literature.
Example
x
7
5
8
10
9
25
10
30
11
50
12
200
Reaction Sequence
Hydrosilylation reactions are known and are shown in the reaction below:
General Procedure
The specified number of grams of the specified Silanic Hydrogen intermediate (Examples 7-12) is added to 500.0 grams of methyl undecylenate. The reaction is blanketed under nitrogen heated to 80° C. Next add 500 ppm (parts per million) of Karnstedt catalyst (based upon the total weight of methyl undecylenate and silanic hydrogen compound). An exotherm will result bringing the temperature to 100° C. Keep the temperature at between 100° C. and 120° C. for 2 hours. Any excess methyl undecylenate is removed using vacuum.
The product is used without additional purification.
Non Homopolymers
Silanic Hydrogen
Example
Example
Grams
13
7
506.0
14
8
876.0
15
9
1986.0
16
10
2356.0
17
11
3836.0
18
12
14936.0
Compounds of the Present Invention
General Procedure
To a reaction flask equipped with agitation, heat and a distillation is added the specified number of grams of the specified carboxy silicone is added the specified number of grams of the specified hydroxy silicone. Next is added 0.1% by weight of stannous oxylate (based upon the combined weight of the carboxy and hydroxy silicones). The heat is turned on and the reaction mass is heated to 200° C. Methanol is distilled off. Once the amount of methanol approaches 95% of theoretical the mass will get very thick. Allow to cool.
The resulting product is diluted with isododecane to between 50% by weight of polymer.
The range of dilution can be between 20% and 60% by weight of polymer but 50% by eight of polymer is preferred. The dilution will cut the viscosity and the product will be easily flowable. Suitable other solvents include D5 (cyclopentasiloxane) and a variety of esters including triglycerides and natural oils.
Preferred Homopolymers
In a preferred embodiment x and y are both between 25 and 50.
Carboxy Silicones
Hydroxy Silicones
Example
Example
Grams
Example
Grams
19
15
2383.0
3
2102.0
20
16
2752.0
4
2472.0
21
17
4232.0
5
3952.0
22
15
2383.0
5
3952.0
23
16
2752.0
3
2102.0
24
17
4232.0
4
2472.0
Less Preferred Non-Homopolymers
Carboxy Silicones
Hydroxy Silicones
Example
Example
Grams
Example
Grams
25
15
2383.0
1
622.0
26
16
2752.0
2
992.0
27
17
4232.0
6
15502.0
28
13
902.0
1
622.0
29
14
1272.0
2
992.0
30
13
902.0
6
15052.0
Applications Examples
The compounds (examples 19-30) were evaluated at 50% solids in isododecane. 2 grams of product were placed on glass plated and allowed to dry overnight. The resulting film was evaluated on a scale of 0-5 (with 5 being best, 0 being worst). The Ability to form a film on dry down was evaluated as well as the ability to pull the film off the glass without breaking again using a scale of 0-5 (with 5 being best, 0 being worst). The results are shown below.
Preferred
Example
Film Formation
Flexibility
19
5
5
20
4
5
21
5
4
22
5
5
23
4
4
24
4
4
Less Preferred
Example
Film Formation
Flexibility
25
3
3
26
3
3
27
2
3
28
3
3
29
2
3
30
2
3
As can readily be seen the compounds of the current invention are good flexible film forming polymers that have flexibility. The preferred embodiment polymers (that is when x and y are both between 25 and 50) are outstanding products.
While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth hereinabove but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains. | The present invention is directed to a group of silicone polyesters and a process for making them by reacting a specific carboxy silicone and a hydroxy silicone to make a surprisingly organic soluble, more biodegradable film forming resin. Additionally, the invention discloses a process for applying pigment to a substrate including skin, metal or glass, which comprises contacting the skin with a dispersion of pigment, a volatile solvent, and the resin disclosed. | 0 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a Divisional Application of U.S. patent application Ser. No. 12/402,589, which was filed on Mar. 12, 2009, which is all incorporated by reference herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an electronic device, and more particularly to a capacitor with a floating metal ring.
2. Description of the Related Art
Capacitors are essential passive elements in integrated circuits. In integrated circuits, differential signals on two electrodes of a capacitor are easily affected by nearby routed conducting lines. FIG. 1 shows a capacitor of symmetric metal-oxide-metal (MOM) structure. Electrodes E 10 and E 11 and an oxide layer therebetween form a capacitor CP 1 . If there is a conducting line L 10 near the capacitor CP 1 , parasitic capacitors are formed between the conducting line L 10 and the electrodes E 10 and E 11 . FIG. 2 shows an equivalent circuit of the MOM structure and the conducting line L 10 . Referring to FIGS. 1 and 2 , C 10 represents the parasitic capacitor between the conducting line L 10 and the electrode E 10 , and C 11 represents the parasitic capacitor between the conducting line L 10 and the electrode E 11 . Noise on the conducting line L 10 directly affects the differential signals on the electrodes E 10 and E 11 . Moreover, since the electrode E 11 is farther away than the electrode E 10 from the conducting line, the parasitic capacitor C 11 is smaller than the parasitic capacitor C 10 , so that, the differential signals on the electrodes E 10 and E 11 suffer unequal effects from the conducting line L 10 .
BRIEF SUMMARY OF THE INVENTION
An exemplary embodiment of an electronic device comprises first and second electrodes and a first floating metal ring. The first and second electrodes are formed in a first layer. The first floating metal ring is formed in the first layer and encloses the first electrode and the second electrode. The first electrode and the second electrode are formed in an L-type shape, a ladder-type shape, a finger-type shape, a zipper-type shape, or a hook-type shape.
Another exemplary embodiment of an electronic device comprises first and second electrodes and a first floating metal ring. The first and second electrodes are formed in a first layer and are symmetrically disposed with respect to a first point. The first floating metal ring is formed in the first layer and encloses the first electrode and the second electrode. In some embodiments, the floating metal ring is symmetrically disposed with respect to the first point.
Another exemplary embodiment of an electronic device comprises first and second electrodes and a first floating metal ring. The first and second electrodes are formed in a first layer and are disposed in rotational symmetry with respect to a first symmetry point. The floating metal ring is formed in a first layer and encloses the first electrode and the second electrode. In some embodiments, the floating metal ring is disposed in rotational symmetry with respect to the first symmetry point.
Another exemplary embodiment of an electronic device comprises a first electrode, a second electrode, and a floating plate. The first and second electrodes are formed in a first layer. The floating plate is disposed under the first electrode and the second electrode. In some embodiments, the electronic device further comprises two walls disposed two sides of the electronic device.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
FIG. 1 shows a capacitor of symmetric metal-oxide-metal (MOM) structure;
FIG. 2 shows an equivalent circuit of the MOM structure and the nearby conducting line of FIG. 1 ;
FIG. 3 a shows an exemplary embodiment of a capacitor;
FIG. 3 b shows an exemplary embodiment of a capacitor;
FIG. 4 shows the capacitor of FIG. 3 a and a nearby conducting line;
FIG. 5 shows an equivalent circuit of the capacitor and the nearby conducting line of FIG. 4 ;
FIG. 6 shows an equivalent circuit transformed from the equivalent circuit of FIG. 5 by Y-Δ transformation;
FIGS. 7 a and 7 b show the electrodes with zipper-type shapes in the capacitor of FIG. 3 a;
FIG. 7 c shows a woven structure formed by overlapping the electrodes with the zipper-type shapes of FIGS. 7 a and 7 b in two layers;
FIGS. 8 a and 8 b show the electrodes with hook-type shapes in the capacitor of FIG. 3 a;
FIG. 8 c shows another woven structure formed by overlapping the electrodes with the hook-type shapes of FIGS. 8 a and 8 b in two layers;
FIGS. 9 a and 9 b show the electrodes with L-type shapes in the capacitor of FIG. 3 a;
FIG. 9 c shows a woven structure formed by overlapping the electrodes with the L-type shapes of FIGS. 9 a and 9 b in two layers;
FIGS. 10 a and 10 b show the electrodes with ladder-type shapes in the capacitor of FIG. 3 a;
FIG. 10 c shows another woven structure formed by overlapping the electrodes with the ladder-type shapes of FIGS. 10 a and 10 b in two layers;
FIG. 11 shows an exemplary embodiment of a capacitor;
FIG. 12 shows an exemplary embodiment of the floating plate of the capacitor in FIG. 11 ; and
FIG. 13 shows an exemplary embodiment of a capacitor.
DETAILED DESCRIPTION OF THE INVENTION
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
Capacitors are provided. In an exemplary embodiment of a capacitor in FIG. 3 a , a capacitor CP 3 comprises electrodes E 30 and E 31 , an insulator (not shown), and a floating metal ring R 30 a . The insulator can be oxide, so that the capacitor CP 3 has a metal-oxide-metal (MOM) structure. In this embodiment, the electrodes E 30 and E 31 , the insulation layer, and the floating metal ring R 30 a are formed in the same layer. Referring to FIG. 3 a , each of the electrodes E 30 and E 31 has a finger-type shape, and the electrodes E 30 and E 31 are symmetrically disposed with respect to a point SP 3 . Fingers of the electrodes E 30 and E 31 extend toward the symmetry axis SA 3 and are alternately disposed. The floating metal ring R 30 a encloses the electrodes E 30 and E 31 and is symmetrically disposed with respect to the point SP 3 . Referring to FIG. 4 , it is assumed that there is a conducting line L 30 near the capacitor CP 3 . Due to the floating metal ring R 30 a , noise on the conducting line L 30 does not directly affect the differential signals on the electrodes E 30 and E 31 .
FIG. 5 shows an equivalent circuit of the capacitor CP 3 and the conducting line L 30 . A parasitic capacitor C 30 is formed between the floating metal ring R 30 a and the electrode E 30 , and a parasitic capacitor C 31 is formed between the floating metal ring R 30 a and the electrode E 31 . A parasitic capacitor C 32 is formed between the conducting line L 30 and the capacitor CP 3 . Since the electrodes E 30 and E 31 and the floating metal ring R 30 a are symmetrically disposed with respect to the point SP 3 , the parasitic capacitors C 30 and C 31 between the floating metal ring R 30 a and the electrodes E 30 and E 31 have the same capacitance, so that the differential signals on the electrodes E 30 and E 31 suffer equal effects from the conducting line L 30 .
In another aspect, the capacitance between the electrodes E 30 and E 31 can be increased due to the disposition of the floating metal ring R 30 a . FIG. 6 shows an equivalent circuit transformed from the equivalent circuit in FIG. 5 by Y-Δ transformation. Capacitors C 60 -C 62 in FIG. 6 are formed according to the capacitors C 30 -C 32 in FIG. 5 , and shown in following equations:
c
60
=
c
61
=
c
32
×
c
30
c
32
+
2
c
30
=
c
32
c
32
c
30
+
2
<
c
32
2
,
and
c
62
=
c
30
2
c
32
+
2
c
30
=
c
30
c
32
c
30
+
2
<
c
30
2
,
wherein, c 30 -c 32 and c 60 -c 62 represent the capacitance of the capacitance capacitors C 30 -C 32 and C 60 -C 62 , respectively.
According to above equations, since the capacitor CP 3 and C 62 are coupled in parallel, the capacitance between the electrodes E 30 and E 31 is increased from cp 3 to cp 3 +c 62 , wherein cp 3 represents the capacitance of the capacitor CP 3 . Moreover, the values c 60 and c 61 of the parasitic capacitors C 60 and C 61 between the conducting line L 30 and the electrodes E 30 and E 31 are equal, and each of the values c 60 and c 61 is less than
c 32 2 ,
so that the differential signals on the electrodes E 30 and E 31 suffer equal effects from the conducting line L 30 , and the effects on the differential signals are weak.
In the embodiment of FIG. 3 a , the floating metal ring R 30 a strictly encloses the electrodes E 30 and E 31 . In some embodiments, a floating metal ring R 30 b has a breaking 301 , so that the floating metal ring R 30 b does not strictly enclose the electrodes E 30 and E 31 . Moreover, the floating metal ring R 30 b is symmetrically disposed with respect to a symmetry axis SA 3 .
In the embodiment of FIG. 3 a , the capacitor CP 3 is formed by a single layer with the electrodes E 30 and E 31 , the insulator, and the floating metal ring R 30 a . In other embodiments, the capacitor CP 3 can be form by a plurality of layers with electrodes. Each of the layers comprises electrodes E 30 and E 31 and the insulator, and at least one layer comprises the floating metal ring R 30 a . Referring to FIG. 3 a , the electrodes E 30 and E 31 with the finger-type shape are symmetrically disposed with respect to the point SP 3 . However, the shapes of the electrodes E 30 and E 31 are not limited to the finger-type shape. The electrodes E 30 and E 31 can have any shape to be symmetrically disposed with respect to the point SP 3 .
In some embodiments, the electrodes E 30 and E 31 can be disposed in rotational symmetry with respect to a symmetry point. For example, the electrodes E 30 and E 31 of the capacitor CP 3 can have zipper-type shapes as shown in FIGS. 7 a and 7 b or hook-type shapes as shown in FIGS. 8 a and 8 b . The electrodes E 30 and E 31 with the zipper-type shapes in FIGS. 7 a and 7 b are respectively disposed in rotational symmetry with respect to symmetry points SP 7 a and SP 7 b . The electrodes E 30 and E 31 with the hook-type shapes in FIGS. 8 a and 8 b are respectively disposed in rotational symmetry with respect to symmetry points SP 8 a and SP 8 b . If the capacitor CP 3 is formed by electrodes in a plurality of layers, each of the layers comprises electrodes E 30 and E 31 with the zipper-type shape or the hook-type shape and the insulator, and at least one layer comprises the floating metal ring R 30 a . In following, it is assumed that the capacitor CP 3 is formed by electrodes in two layers. When the electrodes E 30 and E 31 of one layer have the zipper-type shape as in FIG. 7 a and those of the other layer have the zipper-type shape as in FIG. 7 b , the capacitor CP 3 is formed in a woven structure by overlapping the two layers, as shown in FIG. 7 c . Similarly, when the electrodes E 30 and E 31 of one layer have the hook-type shape as in FIG. 8 a and those of the other layer have the hook-type shape as in FIG. 8 b , the capacitor CP 3 is formed in a woven structure, as shown in FIG. 8 c , by overlapping the two layers. Moreover, according to symmetric geometry, the electrodes E 30 and E 31 with the figure-type shape and the floating metal ring R 30 a as in FIG. 3 a are also disposed in rotational symmetry with respect to a symmetry point SP 3 . In FIGS. 7 c and 8 c , two layers of a capacitor are coupled together through vias represented by dark blocks.
According to above description, electrodes in one layer of a capacitor are disposed in rotational symmetry with respect to a symmetry point, and a floating metal ring in the same layer encloses the electrodes. Noise on a nearby conducting line does not directly affect differential signals on the electrodes. The differential signals suffer equal effects from the conducting line, and the effects on the differential signals are weak.
In other some embodiments, the electrodes E 30 and E 31 can be disposed in asymmetry. For example, the electrodes E 30 and E 31 of the capacitor CP 3 can have L-type shapes as shown in FIGS. 9 a and 9 b or ladder-type shapes as shown in FIGS. 10 a and 10 b.
If the capacitor CP 3 is formed by electrodes in a plurality of layers, each of the two layers comprises electrodes E 30 and E 31 with the L-type shape or the ladder-type shape and the insulator, and at least one layer comprises the floating metal ring R 30 a . In following, it is assumed that the capacitor CP 3 is formed by electrodes in two layers. When the electrodes E 30 and E 31 of one layer have the L-type shape as in FIG. 9 a and those of the other layer have the L-type shape as in FIG. 9 b , the capacitor CP 3 is formed in a woven structure by overlapping the two layers, as shown in FIG. 9 c . Similarly, when the electrodes E 30 and E 31 of one layer have the ladder-type shape as in FIG. 10 a and those of the other layer have the ladder-type shape as in FIG. 10 b , the capacitor CP 3 is formed in a woven structure, as shown in FIG. 10 c , by overlapping the two layers. In FIGS. 9 c and 10 c , two layers of a capacitor are coupled together through vias represented by solid blocks.
According to the above description, a capacitor comprises two electrodes disposed in asymmetry and two connected floating metal rings, each enclosing the electrode in the same layer, so that noise on a nearby conducting line does not directly affect differential signals on the electrodes.
In another embodiment of a capacitor in FIG. 11 , a capacitor CP 11 comprises electrodes E 110 and E 111 , an insulator (not shown), and a floating plate 110 . The electrodes E 110 and E 111 can have a symmetric shape, such as the sharps of FIGS. 3 a , 7 a , 7 b , 8 a , and 8 b . The floating plate 110 is disposed under the electrodes E 110 and E 111 . A parasitic capacitor is formed between the floating plate 110 and the electrode E 110 , and another parasitic capacitor is formed between the floating plate 110 and the electrode E 111 . Since the electrodes E 110 and E 111 have the symmetric shape, these parasitic capacitors between the floating plate 110 and the electrodes E 110 and E 111 have the same capacitance, so that the differential signals on the electrodes E 110 and E 111 suffer equal effects from the conducting line L 110 . Thus, the floating plate 110 can shield against imbalance capacitance effect between the line L 110 and the electrodes E 110 and E 111 .
In the embodiment of FIG. 11 , the surface of the floating plate 110 is smooth. In some embodiments, the floating plate 110 can have trenches or slices or other kinds of holds. The floating plate 110 with trenches in FIG. 12 is given as an example.
Moreover, the capacitor CP 11 of FIG. 11 may further comprise walls. As shown in FIG. 13 , the capacitor CP 11 further comprises walls W 30 and W 31 which are disposed two sides of the capacitor CP 11 . In this embodiment, the walls W 30 and W 31 are disposed the two opposite sides of the capacitor CP 11 . One wall W 30 is formed by an upper conductive line 130 and lower conductive lines 132 , and the upper conductive line 130 is connected with the lower conductive lines 132 . There are holds formed between the lower conductive lines 132 the upper conductive line 130 , and the corresponding side of the capacitor CP 11 . The other wall W 31 is formed by an upper conductive line 132 and lower conductive lines 133 , and the upper conductive line 132 is connected with lower the conductive lines 133 . There are holds formed between the lower conductive lines 133 , the upper conductive line 132 , and the corresponding side of the capacitor CP 11 . The walls W 30 and W 31 and the floating plate 110 can shield against imbalance capacitance effect between the line L 130 and the electrodes E 110 and E 111 .
The floating metal rings, the floating plate, and the walls which are provided to shield against imbalance capacitance are not limited to a capacitor element. In some embodiments, the floating metal rings, the floating plate, and the walls can be used to shield against imbalance capacitance occurred in a resistor element or any other circuit, such as an amplifier circuit.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. | A electronic device is provided. The electronic device includes a first electrode formed in a first layer; a second electrode formed in the first layer, wherein the first electrode and the second electrode are symmetrically disposed with respect to a first point; and a first floating metal ring formed in the first layer and enclosing the first electrode and the second electrode. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to magnetoresistive magnetic read and read/write heads, and more particularly, to method and apparatus for applying easy-axis bias to the magnetoresistive element of a magnetoresistive (MR) head.
A magnetic recording head can write digital data on a magnetic storage disk by varying the orientation of the magnetization (i.e., magnetic domains or groups of domains) within the disk's magnetic storage layer. The boundaries between oppositely oriented magnetic domains are called "transitions", and it is these transitions which represent stored data. A magnetoresistive magnetic head reads (i.e., retrieves) this stored data from the moving disk by sensing magnetic flux changes caused by the stored transitions passing by close enough to the pole tip to couple into the pole and which flux is then carried to and interacts with the magnetoresistive element. More particularly, the vertical component of the stray flux emanating from transitions recorded in the medium and conveyed up through the pole tip rotates the magnetization of the magnetoresistive element, which effects a detectable resistive change in the element. This resistive change is employed for data detection.
As seen in the top view of FIG. 1(A) and the sectional view of FIG. 1(B), a simplified magnetoresistive head 10 includes a magnetoresistive element 12 coupled to a magnetic pole 14. Pole 14 defines a narrowed pole tip portion 14a which terminates in a pole tip 16 at the air bearing surface (ABS) of the head, and has a separate yoke portion 14b at the back of the head. The magnetoresistive element magnetically couples the pole's tip and yoke portions. The head flies over, and with its ABS essentially parallel to, the surface of rotating magnetic storage disk 17 for capture of flux from passing transitions on disk 17. The captured flux travels from the disk, through tip portion 14a, through magnetoresistive element 12, through yoke portion 14b, and then returns back to the disk.
A closed sensing/detection circuit is created by coupling the magnetoresistive element, via its leads 18, to a detection circuit 20. The detection circuit 20 applies a constant dc bias current to the magnetoresistive element, such that changes in the magnetoresistive element's resistance are detected as a change in voltage level in the sensing/detection circuit. Hence, variations in the element's resistance, detected as variations in the voltage level of the magnetoresistive sense signal and correlated with the transitions detected by the magnetoresistive element, can be correlated with detection of stored data for data recovery purposes.
In addition to the applied sense current, a magnetoresistive element requires two further species of biasing. Transverse or hard axis biasing (see arrow H) is applied to the magnetoresistive element to cant its magnetization in the central portion of the magnetoresistive element at 45 degrees to the easy axis, which drives the magnetoresistive element into a linear response mode. This linearity eases the data recovery task of the detection circuit.
Longitudinal or easy axis biasing (see arrow E) is applied along the length of the magnetoresistive element to force it into a single magnetic domain or a series of domains in a single orientation, which keeps domain walls from forming in the element and thus prevents Barkhausen noise, i.e., sudden jumps in the magnetoresistive sense signal attributed to signal-field-induced movement of domain walls in the magnetoresistive element. An easy axis field of a few Oersteds will typically prevent domain wall formation.
U.S. Pat. No. 4,903,158 discloses a magnetoresistive head with a permanent magnet easy axis biasing structure having the same (or nearly the same) physical geometry as the magnetoresistive element (called a sense film) itself. In this arrangement, a similar but opposite demagnetization field is generated in this biasing structure as is generated in the sense film. These demagnetizing fields complimentarily cancel each other, and therefore the tendency of forming multiple and disordered domains in the magnetoresistive sense film is reduced, therefore reducing the likelihood of Barkhausen noise.
This known device includes a soft magnetic layer (such as permalloy) deposited on a non-magnetic substrate, with an SiO 2 insulation layer formed thereover and a 400 Å magnetoresistive sense film deposited on the SiO 2 layer. Electrical bonding pads are next formed on the magnetoresistive sense film for conveyance of the sense signal to the detection circuit. The constant dc sense current through the magnetoresistive sense film magnetizes the soft layer generally along the current path, which in turn biases the magnetic moment, or orientation, of the magnetoresistive sense film magnetization at about 45 degrees to the magnetoresistive current path into a linear response mode. Next, a 1000 Å coating of SiO 2 is deposited on the sense film/contact pad structure followed by a layer of magnetically hard material (about 1000 Å) is deposited atop this coating. This assembly is exposed to a strong magnetic field in a first direction so as to permanently magnetize the magnetically hard layer. The magnetoresistive sense film is then exposed to a weaker magnetic field in an opposite direction so that the magnetic moment of the magnetoresistive film is oriented in the direction of the external magnetic field of the magnetically hard layer.
For a detailed discussion of magnetoresistive head technology, see Markham and Jeffers, MAGNETORESISTIVE HEAD TECHNOLOGY, Proceedings Of The Symposium On Magnetic Materials, Processes, and Devices, Electromechanical Society, Vol. 90-8, pp. 185-204 (1990), the contents of which are incorporated herein by reference.
It is an object of the present invention to provide a magnetoresistive thin film head having magnetic easy axis biasing supplied from a magnetic source formed without process complexity.
It is another object of the present invention to provide a magnetoresistive thin film head having magnetic biasing supplied from a magnetic source not immediately adjacent to the magnetoresistive element so as to avoid the possibility of electrical shorts occurring between the source and the element.
SUMMARY OF THE INVENTION
These objects are well met in the presently disclosed method and apparatus for supplying bias to a magnetoresistive element in a thin film head for reducing the likelihood of Barkhausen noise being generated when reading flux from a magnetic storage disk. The invention achieves a relatively uniform easy axis bias field in an easy to implement manner.
An encapsulated thin film magnetic head for sensing of flux from a magnetic storage disk in practice of the invention may take the form of an element-in-the-yoke type or element-in-the-gap type head. Easy axis bias is supplied by a magnetic source formed on the encapsulated head in a plane above the plane of the MR element and separated from the MR element by a distance sufficient to negate the likelihood of electrical shorts between the magnetic source and the MR element. Hard axis bias may be provided via the write coil or via a soft adjacent layer formed near or on the MR element, or may be provided along with easy axis bias by the magnetic source formed on the encapsulated head. Preferably the magnetic source on the encapsulation layer is a permanent bar magnet, although other active and passive magnetic structures are also within the scope of the invention.
In an element-in-the-yoke embodiment of the invention, a thin film magnetic head for sensing of flux from a magnetic storage disk includes a base structure, which may include a first magnetic pole formed on a non-magnetic substrate, and a magnetoresistive read pole formed on the base structure. The read pole includes a pole tip portion and a yoke portion which are coupled to each other via a magnetoresistive element. The read pole portions are made of high-permeability material, typically thicker than the MR element, so as to enhance flux conduction. The magnetoresistive element is coupled toward its respective ends to respective sense leads. The sense leads terminate at pads which penetrate an encapsulation layer, although an additional magnetic pole structure may be first formed over the read pole prior to forming the encapsulation layer. The head further includes a magnet structure formed on the encapsulation layer for providing bias to the magnetoresistive element. This biasing structure may be incorporated into both monopole and multi-pole magnetoresistive heads.
In an element-in-the-gap embodiment of the invention, at least one magnetic pole lies between a magnetic source formed on the head encapsulation layer and the MR element. The tip of that pole is tapered to permit magnetic interaction between the magnetic source and the MR element for supply of easy axis bias thereto.
A method for forming a magnetically biased MR head according to the invention includes forming a bottom pole over a non-magnetic substrate, and forming a magnetoresistive element thereover upon an intermediate insulation layer. Leads are also formed, extending out from non-central locations on the MR element. The central portion of the MR element, i.e., that portion between the leads attachment locations, defines the active region of the element. Another insulation layer is formed over the MR element in preparation for deposition of the read pole tip portion and yoke portion, which are then formed accordingly. These read pole portions are formed of soft magnetic material, such as NiFe.
A combination of insulation layers are then formed over the read pole (with a write coil preferably formed within the layers if the head is to have a write capability). The top pole is deposited and formed over this structure. The head is now enclosed in a protective encapsulation layer. The encapsulation layer is planarized to enable further processing and which exposes the ends of the element's leads. (Also, if a write coil is included, then the ends of the write coil leads are also exposed.) This portion of the above-described head is conventional.
If the finished head were to be conventional, a metallic seed layer, such as a layer 2000 Å thick, would be formed over this structure, with gold contact pads being formed on this seed layer (such as by masked deposition) over the location of, and thus electrically coupled to, the exposed element leads'ends. However, in the present invention, a high coercivity (hard) magnetic seed layer, such as a NiCo layer 2000 Å thick, is deposited over the planarized encapsulation layer. Now, using an appropriately modified mask, an additional gold bar structure is formed along with the contact pads by thru-mask gold deposition upon the high coercivity magnetic seed layer. The resulting plated gold structures serve to mask the locally underlying magnetic seed layer so that as etching of the exposed seed layer (i.e., not underlying the pads and bar) proceeds, three magnetic structures of gold upon high coercivity seed layer are formed on the encapsulation layer.
The resulting structure of this head includes contact pads for coupling the magnetoresistive element via its leads, respectively, to a detection circuit, and also a permanent bar magnet (i.e., the magnetic seed layer portion under the gold bar). The bar magnet will be formed long enough so as to present an essentially uniform longitudinal field over the length of the MR element or at least to the active portion of the MR element lying between the leads for providing biasing thereto. With the longitudinal axis of the bar magnet aligned with the longitudinal axis of the magnetoresistive element, a single domain configuration can be established in the MR element, as will reduce the likelihood of unwanted Barkhausen noise.
More particularly, easy axis bias is provided to the MR element by the resulting magnetic seed layers structures underlying the pads and bar, with the layer underlying the bar dominating this effect. The magnetic seed layer structures underlying the pads may be used to provide a transverse hard axis bias component such as by being formed of dissimilar size or location. Alternatively the seed layer under the gold bar may be characterized (in shape or orientation) to also provide the hard axis bias itself. For example, the bar magnet magnetization may be aligned with the MR element to supply easy axis bias or canted so as to supply both easy and hard axis bias.
As a result of the foregoing, biasing can be supplied to a magnetoresistive head without additional process complexity, since the bar magnet is formed simply by modifying the conventional mask already required for forming the contact pads, along with substituting a high coercivity seed layer for the conventional seed layer.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention will be more fully understood by reference to the following detailed description in conjunction with the attached drawing in which like reference numerals refer to like elements and in which:
FIG. 1A and 1B provide a top view (A) and a side view through line 1B--1B (B) of a simplified prior art MR head.
FIG. 2A, 2B, 2C, 2D, and 2E provide a side view (2A) and a schematic view (2B) of an embodiment of the invention; a top view (2C) of a partially completed slider incorporating the head Of FIG. 2(A-B); a partial top view (2D) of a completed slider incorporating the head of FIG. 2(A-B), and a deposition mask (2E) employed in forming the bias structure of this embodiment.
FIG. 3 shows the longitudinal field of a typical bar magnet.
FIG. 4A and 4B provide a top view (4A) and an ABS view (4B) of an alternative embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A three pole magnetoresistive head 30 in practice of an embodiment of the present invention is shown in FIG. 2(A-D). A bottom pole 34 is formed over non-magnetic substrate 32, and a magnetoresistive element 38 is formed thereover upon an intermediate insulation layer 36. Leads 46a, 46b are also formed, extending out from non-central locations on the MR element. The central portion of the MR element, i.e., that portion between the leads attachment locations, defines the active region 38a of MR element 38.
Another insulation layer 40 is formed over the MR element in preparation for deposition of the read pole tip portion 42 and yoke portion 44, which are then formed accordingly. These read pole portions are formed of soft magnetic material, such as NiFe.
A combination of insulation layers 46 are then formed over the read pole (with a write coil 48 formed within layers 46 if the head is to have a write capability). The top pole 50 is deposited and formed over this structure. The head is now enclosed in a protective encapsulation layer 52.
The head is formed in a larger physical structure called a slider, and which has aerodynamic features for interaction with the disk over which it flies. The top 59 of a slider incorporating head 30 is shown in FIG. 2(C), wherein it will be appreciated that the encapsulation layer 52 has been planarized to enable further processing and which planarizing exposes the ends 56a, 56b of the element's leads 46a, 46b, respectively. Although head 30 is not exposed, it is shown here as a matter of convenience, so as to locate the exposed lead ends. (Also, if a write coil is included, then the ends of the write coil leads are also exposed and would be shown.) This portion of the above-described head 30 is conventional.
If the head of FIG. 2(A-D) were conventional, a metallic seed layer, such as a layer 2000 Å thick, would be formed over this structure, with gold contact pads being formed on this seed layer (such as by masked deposition) over the location of, and thus electrically coupled to, the exposed element ends 56a, 56b. However, in the present invention, a high coercivity (hard) magnetic seed layer 58, such as a NiCo layer 2000 Å thick, is deposited over the planarized encapsulation layer 52.
At this point, contact pads must be formed on the seed layer, such as by masked deposition of gold. This is achieved in the present invention by using an appropriately modified mask 90 (see FIG. 2(E)), with which an additional gold bar structure 62 is formed along with contact pads 60a, 60b, again by thru-mask gold deposition, upon the high coercivity magnetic seed layer 58. Now the portion of the seed layer which connects structures 60a, 60b and 62 must be removed, such as by etching. In fact, the plated gold structures 60a, 60b, 62 serve to mask the locally underlying magnetic seed layer 58 so that as etching of the exposed seed layer 58 (i.e., not underlying pads 60a, 60b and bar 62) proceeds, three magnetic structures 60a', 60b' and 62' of gold-upon-high-coercivity-seed-layer are formed on the encapsulation layer 52.
The resulting structure of head 30 includes contact pads 60a, 60b for coupling the magnetoresistive element 40 via its leads 46a, 46b, respectively, to a detection circuit, and also a permanent bar magnet 62' (i.e., the magnetic seed layer portion under gold bar 62).
The magnetic field from a simple bar magnet 64 is shown in FIG. 3. Along the sides of the magnet away from the ends a fairly uniform longitudinal field exists. Accordingly, bar magnet 62' shown in FIG. 2(D) should be formed long enough so as to present an essentially uniform longitudinal field over the length of the MR element or at least to the active portion of the MR element lying between the leads, for providing easy axis biasing thereto. With the longitudinal axis of bar magnet 62' aligned with the longitudinal axis of the magnetoresistive element 38, a single domain configuration can be established in the MR element, as will reduce the likelihood of unwanted Barkhausen noise.
In this embodiment, easy axis bias to the MR element is provided by the resulting magnetic structures 62', 60a', 60b', with bar 62' dominating this effect. Alternatively, the magnetic structures 60a', 60b' may be used to provide a transverse hard axis bias component such as by being formed of dissimilar size or location, or the easy-axis-providing bar magnet 62' may be characterized (in shape or orientation) to also provide the hard axis bias itself.
As a result of the foregoing, easy axis biasing can be supplied to a magnetoresistive head without additional process complexity, since the bar magnet 62' is formed simply by modifying the conventional mask already required for forming the contact pads, along with substituting a high coercivity seed layer for the conventional seed layer.
The foregoing embodiment is generally referred to as an element-in-the-yoke type magnetoresistive head having a bias magnet. In an alternative embodiment, as shown in FIG. 4(A-B), an element-in-the-gap type magnetoresistive head 70 having the bias magnet 62' formed on encapsulation layer 72 is disclosed. In this embodiment, the MR element 73 is formed in the gap g between the tips of poles (or shields) 74, 76, near or adjacent to the air bearing surface (ABS) of the head. In a conventional head these poles would have a width W as shown, even at the air bearing surface, however in the present embodiment, the width of the poles at the air bearing surface is reduced to W', i.e., they are narrowed to a width roughly equal to the track width the data recorded on the disk at pole tips 74', 76'.
This width W' is selected in view of two competing requirements: it must be small enough to avoid shielding the MR element from the desirable easy biasing effects of the magnet 62'; and it must be large enough to provide shielding to the MR element from the flux emanating from tracks adjacent to the track of interest.
The leads are affixed to the MR element in a conventional manner, and for ease of presentation only, are shown in FIG. 4(B) as L1 and L2. The area of the MR element between the two conductors is the active area where the flux from the disk is sensed. Here the hard axis bias field is perpendicular to the longitudinal axis of the element. Enough hard axis bias must be applied to cause the magnetization to rotate to about 45 degrees from the element's longitudinal axis, so as to obtain maximum sensitivity and linearity of the magnetoresistive effect. Hard axis bias is supplied to head 70 via soft adjacent layer 78.
Soft adjacent layer 78 is magnetically close to the MR element, although insulated therefrom. The dc sense current applied to the MR element via leads L1, L2 produces a field which magnetizes the soft adjacent layer 78. The resultant field in this soft layer reacts back upon the magnetization of the element, providing the required hard axis bias field.
The structure of head 70 includes an insulated substrate base 79 upon which bottom pole 74 is formed (although only pole tip 74' of pole 74 is shown in FIGS. 4(A,B)). MR element 73 is formed on an insulation layer (not shown) over the bottom pole, with a small insulation barrier 80 formed over the central (sensing) portion of the element. The soft adjacent layer 78 is formed on the combined barrier 80 and element 73. The function of barrier 80 is to prevent the soft layer from being in direct magnetic contact with the MR element at that location so as to be able to effectively provide transverse bias thereto. An insulation layer (not shown) is formed over this structure and the upper pole 76 is formed thereon. This workpiece is now covered by encapsulation layer 72, which is then planarized for forming thereon the above-described gold covered bar magnets and contact pads, as shown in FIG. 2. The bar magnet is formed having a thickness chosen according to a desired degree of generated bias.
After the head is fabricated it is subjected to a strong external magnetic field to set the magnetization of the hard layer. The direction of the field is chosen to provide easy axis bias (field parallel to longitudinal axis of the MR element) or alternatively, easy and hard axis bias (by canting the field).
It will be appreciated that, merely by revising the mask required in any event to form the contact pads, it is possible to form the permanent magnet biasing structure of the invention. No additional process steps are required. As well, the thickness of the encapsulation layer, typically 200,000 Å, prevents electrical shorting between the magnet and the MR element. Furthermore, location of the permanent magnet is set back from the ABS so as not to effect the stored data.
It will be understood that the above description pertains to only several embodiments of the present invention. That is, the description is provided by way of illustration and not by way of limitation. The invention, therefore, is to be limited only according to the following claims. | Method and apparatus for supplying bias to a magnetoresistive element in an encapsulated thin film head for reducing the likelihood of generation of Barkhausen noise when reading flux from a magnetic storage disk. The invention achieves a relatively uniform easy axis bias field in an easy to implement manner by creating a magnetic bias structure on the encapsulated heat at the same time as providing the contact pads for the MR element. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to improvements in lighting systems and more particularly, but not by way of limitation, to a lighting system particularly designed and constructed for illuminating the opposite faces of a picture being viewed in a three dimensional viewing system.
2. Description of the Prior Art
There have been many three dimensional viewers of the stereoscopic type wherein a pair of matched left and right eye images or pictures may be viewed simultaneously to simulate three dimensions. These three dimensional viewing devices normally utilize a pair of pictures arranged side-by-side in a common carrier member, and the lighting thereof is a relatively simple matter during a viewing procedure. However, as shown in my co-pending application Ser. No. 405,392, filed Oct. 11, 1973, now U.S. Pat. No. 3,888,564, and entitled "Viewing System Providing Compatability Between Two Dimensional Pictures and Three Dimensional Viewing Thereof" a stereographic type viewing system is disclosed wherein a single picture having a pair of right eye and left eye images mounted back-to-back may be viewed in the viewer apparatus in three dimensions, but may be equally satisfactorily viewed in the usual two dimensional display. The interior lighting of the viewer of this two dimensional-three dimensional compatibility system becomes somewhat more difficult in that it is important to disperse the light substantially equally across the entire surface of the front as well as the back of the picture disposed within the viewer during the three dimensional viewing process.
SUMMARY OF THE INVENTION
The present invention contemplates a novel lighting system for a viewer of the three dimensional-two dimensional viewing system as shown in my aforesaid application. The novel viewing system comprises a pair of suitable light bulbs mounted within the viewer housing at opposite ends of the picture receiving means in order to provide internal lighting for the viewer. Reflector means is disposed within the housing and arranged with respect to each bulb in a manner for reflecting or directing the light rays emanating therefrom simultaneously onto each face of the picture disposed within the picture receiving means. In addition, certain internal portions of the viewer are provided with mask means which eliminate reflection of the light rays onto unwanted portions of the interior of the viewer housing, and curtains or walls are arranged internally of the housing for screening portions of the interior thereof from the light rays in order to achieve a substantially uniform lighting across each face of the picture and eliminating distracting reflections from light "bouncing" from the internal structures of the viewer housing. The novel lighting system is simple and efficient in operation and economical and durable in construction.
BRIEF DESCRIPTION OF THE DRAWINGS
The single FIGURE is a schematic view of an internal lighting system embodying the invention as utilized in combination with a three dimensional-two dimensional viewing system such as disclosed in my prior co-pending application.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings in detail, structural portions of a suitable three dimensional viewer are schematic wherein reference character 10 generally indicates a suitable picture receiving means comprising a pair of spaced upstanding walls 12 and 14 having inwardly directed flange members 16 and 18, respectively, forming a pair of oppositely directed grooves or recesses 20 and 22 for slidably receiving the opposite side edges of a suitable picture 24 therein. As particularly set forth in my aforementioned application, the picture 24 is of the type having a pair of images mounted in aligned back-to-back relation, with one of said images being a right eye image and the other of said images being a left eye image. Each wall 12 and 14 is preferably substantially surrounding on at least three sides thereof by structural walls 26 and 28 which form a portion of the complete outside walls (not shown) of the viewer whereby a substantially lightproof structure is provided for the viewer. In addition, a first lens 30 is provided within the viewer for sighting through by the right eye 32 of the person utilizing the apparatus, and a second lens 34 is provided for sighting through by the left eye 36 of the person using the apparatus. A first mirror or reflector 38 is disposed within the interior of the viewer apparatus for reflecting the line of sight from the eye 32 to one side of the picture 24 as indicated by the broken lines 40 and 42. A second mirror or reflecting surface 44 is provided within the viewer apparatus for reflecting the line of sight from the left eye 36 through the lens 34 onto a third mirror or reflecting surface 46 as indicated by the broken lines 48 and 50. The mirror 46 then reflects the line of sight of the eye 36 onto the opposite face of the picture 24 as indicated by the broken line 52. Of course, the lenses 30 and 34 and mirrors 38, 44 and 46 are all mounted within the confines of the outer walls (not shown) of the viewer apparatus, and as hereinbefore set forth, it is preferable that the construction of the viewer apparatus be substantially light-proof in order that the internal lighting system as hereinafter set forth may be utilized efficiently for producing the most desirable and effective lighting for the viewing of the picture 24.
The lighting system comprises a first lighting means 54 mounted within the housing (not shown) of the viewer apparatus in the proximity of the upstanding wall 12, but preferably outboard thereof as shown in the drawing. A second lighting means 56 is similarly mounted within the housing of the viewer apparatus in the proximity of the upstanding wall 14, but outboard thereof. The lighting means 54 and 56 are preferably in the form of a light bulb of relatively small physical size, but having a sufficiently great lighting power as to provide sufficient lighting during the viewing of the picture 24 as will be hereinafter set forth. The bulbs may be of any suitable size and voltage, but it is deemed preferable that they be of the miniature type, and of a low voltage. Of course, any suitable power source (not shown) may be utilized for illumination of the bulbs, such as direct current, alternating current, battery means, or the like, with said power source being operably connected with the bulbs in the usual or well-known manner for actuation thereof.
It appears to be essential that the light path of the light emanating from the lighting means 54 and 56 be directed in such a manner that the opposite faces of the picture 24 are substantially equally "flooded" or "washed" with light across the entire picture areas thereof, while at the same time reflections of light from other portions of the interior surfaces of the housing of the viewer should be eliminated. Accordingly, an arcuate reflecting wall 58 is disposed against the inwardly directed portions of the housing wall 26 in order to reflect the rays from the bulb 54 simultaneously onto the opposite faces of the picture 24. The reflector wall 58 preferably extends throughout the length or depth of the viewer housing and casts the light from the bulb 54 over substantially one-half the entire area of the picture 24. Similarly, an arcuate reflector wall 60 is disposed against the inwardly directed sides of the wall 28 for reflecting the light rays from the bulb 26 simultaneously onto the opposite faces of the picture 24 for illuminating substantially the remaining half of the entire area of the picture 24, thus producing light on the entire area of both faces of the picture 24. The reflector wall 58 terminates at a point slightly beyond the edges of the wall 12, as shown at 62 and 64, and a matt or curtain 66 and 68 extends therebeyond for adsorbing the light coming from the bulb 54. It may be preferable that the length of the wall 12 on one side of the flange 16 be approximately one-quarter the width of the picture 24, and the spacing between the end of the wall 12 and the reflector surface 58 be approximately one third the length of the portion of the wall 12 projecting from the flange 16. However, this dimension is not critical. In addition, a curtain or wall 70 terminates the curtain 66 and a similar wall 72 terminates the curtain 68, with the walls 70 blocking the travel of light rays from the bulb 54 in a manner and for a purpose as will be hereinafter set forth.
Similarly, the side edges of the reflector wall 60 terminate at a point slightly beyond the wall 14 as shown at 74 and 76, and matts or curtains 78 and 80 are provided at the terminus of the reflector wall 60 for absorbing light rays from the bulb 56. Also, curtains or walls 82 and 84 interrupt the curtains 78 and 80, respectively, and preclude or block the passage of light from the bulb 56 as will be hereinafter set forth.
In addition to the arcuate reflector walls 58 and 60, it is preferable to provide a reflecting surface on the outer wall of face 86 of the wall 12 and a similar reflecting surface on the outer wall or face 88 of the wall 14. The reflecting surfaces 86 and 88 cooperate with the reflector walls 58 and 60 for projecting and diffusing the available light from the bulbs 54 and 56 onto the opposite faces or opposite planes of the picture 24. A light reflective material is desirable, although the surfaces may be of a matte finish in whole or in part to aid in diffusing the light if necessary. The light distribution is preferably as even as possible across the faces or planes of the picture 24, and the curved or arcuate configuration of the reflector walls 58 and 60 appears to aid in focusing the light for the purpose. It is to be understood, however, that the reflector walls 58 and 60 may be of any desired configuration and are not limited to the particular arcuate configuration shown herein.
It is also preferable that the inwardly directed faces 90 and 92 of the wall 12 and the inwardly directed faces 94 and 96 of the wall 14 be constructed of or covered with a light absorbing material so as to mask the light flow from the bulbs 54 and 56. The mask 94 and 84 preclude the passage or flow of light from the bulb 56 to the eye 32. This particular path is indicated by the broken lines 98, 100, 102 and 104, and it will be apparent that the curtain or wall 84 interrupts this flow of light. The wall 12 is provided with similar masking for purposes of symmetry only, as this particular reflection is not present or does not originate from the light source 54. The masks 78 and 80 absorb any light that might be reflected from the edge of the picture 24, as indicated by the broken lines 106 and 108. It is also preferable to minimize unwanted reflections from the surface of the lenses 30 and 34 when such reflections might interfere with satisfactory viewing of the picture 24. Such a light path is illustrated by the broken lines 110, 112 and 114. This particular path results from one particular selection of lens surface shape and it is to be understood that other paths would occur when lenses of differing contours are used. Different lens radii would produce different overall geometry of the viewing system employed and similar masking may be utilized or provided as required for precluding the unwanted reflections. The outer surfaces of the mask 64, 66, 78 and 80 block any stray light which might inadvertently enter the interior of the viewer housing due to any leakage of light.
The areas designed A and B may be referred to as light boxes, and each light box is particularly designed to maximize the amount of available light reaching the picture planes and at the same time to minimize the unwanted surface reflections that might be seen on the glossy surfaces of the picture 24. Whereas some particular reflections and their manner of elimination is hereinbefore set forth it is to be understood that the same type arrangement may be adapted for eliminating substantially any unwanted reflections. In the design of the lighting system of the invention, the light boxes A and B may be placed in substantially any suitable position within the viewer housing wherein sufficient room or space is available for the component parts of the lighting system and which provides a satisfactory lighting of both sides of the picture 24. A symmetric geometry with respect to the picture planes or the end points of the picture as illustrated herein is preferable, however.
From the foregoing it will be apparent that the present invention provides a novel lighting system particularly designed and constructed for a viewer utilized in the stereographic viewing of a picture comprising a pair of back to back images. The lighting system comprises a pair of light boxes arranged with respect to the picture for simultaneously flooding the opposite sides of the picture with substantially evenly distributed flow of light across the entire surface areas thereof. In addition, masks are provided for interrupting the flow of unwanted reflections and for precluding the application of leakage light against the surfaces of the picture. The overall or end result of the novel lighting system is much the same as the lighting of a stage in a theater wherein the area to be observed is well and evenly lighted and those areas not to be seen are darkened, with disturbing side lighting being substantially eliminated.
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein may be made within the spirit and scope of this invention. | An internal or self-contained lighting system for a viewer utilized in a viewing system which permits the stereoscopic viewing of a photograph, or the like, said photograph also being adapted for two dimensional viewing or display when not being viewed in three dimensions, said lighting system including light bulb means mounted within the viewer housing, reflector means arranged within said housing for cooperation with the bulb means for directing the light emanating therefrom onto the back-to-back images of the picture being viewed, and dispersing the light across the faces of the picture for efficiently illuminating the image during viewing thereof. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device that outputs data to another device via a buffer therein, and a method for testing connection between the semiconductor devices.
2. Description of the Related Art
An electronic apparatus produced by mounting a plurality of LSIs on a board is required to be tested after the mounting to ensure that the LSIs are correctly connected to one another. In one of the test methods for LSIs, a testing jig such as an LSI tester, a probe or the like is connected to an LSI to observe a voltage level, etc. of an output from the LSI. As the LSI that employs thus testing method, an LSI having an improved output buffer for outputting a test signal is proposed so as to, for example, increase the transfer speed of the test signal and decrease noise during the test (Japanese Patent Applications Laid-Open Nos. 2-26412 (1990), 5-55889 (1993), 5-75427 (1993) and 2-25775 (1990)).
A boundary scan method is an example of easily testable methods for LSIs mounted on a board. This boundary scan method is realized by extending a scan method, that is, an easily testable method for the internal of an LSI to an entire board. The specification of the boundary scan method is standardized as the IEED Std. 1149.1.
An expensive in-circuit tester such as the LSI tester is unnecessary for a board mounting LSIs testable by the boundary scan method because the LSIs can be accessed from the edge connector of the board. Therefore, an LSI such as a surface mounted component on which a test probe is difficult to set can be easily tested.
FIG. 1 is a block diagram showing the configuration of a conventional LSI 300 manufactured in accordance with the standard for the boundary scan method. In the LSI 300, signals received through input pins IP1, IP2 and IP3 are supplied to an internal logic 102 via respective input buffers 101, and the internal logic 102 performs a logical operation on the received signals. The LSI 300 further includes output buffers 10T and output pins OP1, OP2 and OP3. Each of the output buffers 107 has an enable terminal 8, that is, an input terminal for an enable signal that controls whether an output driver (described in detail below) is enabled to output data, and an output data terminal 7, that is, an input terminal for the data output by the output driver. When the enable signal becomes significant, the output buffer 107 outputs the data received through the output data terminal 7 from the corresponding output pin OP1, OP2 or OP3 connected to a pad 8 provided to each output buffer 107.
Further, the LSI 300 has, as terminals for test use only, an input pin TMS for a test mode selecting signal that is set when testing the board, a test data input pin TDI, a test clock input pin TCK and a test data output pin TDO. The LSI 300 further includes a boundary scan logic 103; and boundary register cells 104 as a circuit for the test. The boundary scan logic 103 includes an instruction register 103a for loading a test instruction such as an EXTEST instruction for testing connection between the LSIs by outputting a test signal from one LSI to the other, and an instruction decoder 103b for decoding the instruction loaded in the instruction register 103a. The boundary register cells 104 are provided between the respective input buffers 101 and the internal logic 102 and between the internal logic 102 and the respective output buffers 107 corresponding to the respective input pins IP1, IP2 and IP3, the respective enable terminals (ENABLE) 6, and the respective output data terminals (OUTPUT) 7.
The boundary register cells 104 are connected in series to the boundary scan logic 103 so as to form a shift register. When testing connection to another LSI, the boundary scan logic 103 sets test data in the boundary register cells 104, the test data set in each boundary register cell 104 is shifted synchronously with the test clock in a direction indicated by an arrow in the figure. The boundary scan logic 103 outputs values output by the boundary register cells 104 corresponding to the output data terminal 7 via the output buffers 107 to the outside. Further, the boundary scan logic 103 latches the test data input in the input buffer 101 from the other LSI via the input pins IP1IP3 into the boundary register cells 104 on the side of the input buffer 101, and outputs the latching data to the outside via the test data output pin TDO so as to make the values observable.
In the ordinary operation of the LSI 300, an input signal is input to the LSI 300 through the input pins IP1, IP2 and IP3, transferred to the input buffers 101 and the boundary register cells 104 disposed between the input buffers 101 and the internal logic 102, and reaches the internal logic 102. An output signal from the internal logic 102 is transferred to the boundary register cells 104 disposed between the internal logic 102 and the output buffers 107 to reach the output buffers 107, and is output from the output pins OP1, OP2 and OP3.
FIG. 2 is a circuit diagram showing an exemplified configuration of the output buffer 107 in the LSI shown in FIG. 1.
The output buffer 107 shown in FIG- 2 has an output driver 107a formed by CMOS transistors, namely, a P-channel transistor 1 whose source is connected to a power supply and an N-channel transistor 2 whose source is grounded. The gate of the P-channel transistor 1 is connected to the output terminal of a two-input NAND gate 3 receiving an enable signal from the enable terminal 6 and a signal from the output data terminal 7. The gate of the N-channel transistor 2 is connected to the output terminal of a two-input NOR gate 4 receiving an inverted signal generated by inverting the enable signal from the enable terminal 6 by an inverter 5 and the signal from the output data terminal 7. The drains of the P-channel transistor 1 and the N-channel transistor 2 are connected to the pad 8.
When both the enable signal from the enable terminal 6 and the signal from the output data terminal 7 are at a high level, the P-channel transistor 1 in the output driver 107a is turned on. In this case, when the high level is taken as "1", the LSI 300 outputs "1" from the output pin OP1, OP2 or OP3 via the corresponding pad 8. When the enable signal from the enable terminal 6 is at a high level and the signal from the output data terminal 7 is at a low level, the N-channel transistor 2 in the output driver 107a is turned on. In this case, the LSI 300 outputs "0" from the output pin OP1, OP2 or OP3 via the corresponding pad 8.
Next, the procedures in the board test by the boundary scan method will be described referring to FIG. 3. On the board to be tested, an LSI (A) 300a and an LSI (B) 300b both in accordance with the standard for the boundary scan method are mounted. Nodes I1, I2 and I3 are input terminals provided at the board edge, and are connected to input pins IP1, IP2 and IP3 of the LSI (A) 300a, respectively. Nodes A, B and C are wirings for connecting output pins OP1, OP2 and OP3 of the LSI (A) 300a to input pins IP1, IP2 and IP3 of the LSI (B) 300b, respectively. Nodes O1, O2 and O3 are output terminals provided at the board edge, and are connected to output pins OP1, OP2 and OP3 of the LSI (B) 300b, respectively. The board further has, at the edge thereof, input terminals TCK and TMS for the test clock and the test mode selecting signal respectively connected to the input pins TCK and TMS for test use only in boundary scan logics 103 in the LSI (A) 300a and the LSI (B) 300b, a test data input terminal TDI connected to the test data input pin TDI of the LSI (A) 300a, and test data output terminal TDO connected to the test data output pin TDO of the LSI (B) 300b. Further, the test data output pin TDO of the LSI (A) 300a is connected to the test data input pin TDI of the LSI (B) 300b.
Now, a result of the test of the connection between the output pins OP1 through OP3 of the LSI (A) 300a and the input pins IP1 through IP3 of the LSI (B) 300b will be described based on Tables 1 through 3. In Tables 1 through and the following description, the high level is taken as "1" and the low level is taken as "0". Tables 1 through 3 show a pattern observed at the input pins IP1 through IP3 of the LSI (B) 300b corresponding with a test pattern output from the LSI (A) 300a through the nodes A, B and C. Table 1 shows the patterns observed when the LSI (A) 300a and the LSI (B) 300b are correctly connected, Table 2 shows those observed when the node A is short-circuited with a power-supply potential VDD, and Table 3 shows those observed when the nodes A and B are short-circuited.
First, the boundary scan logic 103 sets the boundary register cells 104 of the LSI (A) 300a as to output "1" from the output pin OP1, "0" from the output pin OP2 and "0" from the output pin OP3. When the EXTEST instruction is loaded in the instruction register 103a in the boundary scan logic 103 of the LSI (A) 300a, the output pin OP1 outputs "1" to the node A, the output pin OP2 outputs "0" to the node B and the output pin OP3 outputs "0" to the node C. Then, the signals input from the nodes A, B and C to the input pins IP1, IP2 and IP3 of the LSI (B) 300b, respectively, are latched in the corresponding boundary register cells 104 and the the latched signals are output from the test data pin TDO. Then a tester checks the values of the signals. Next, the values at the boundary register cells 104 in the LSI (A) 300a are shifted so as to output "0" from the output pin OP1, "1" from the output pin OP2 and "0" from the output pin OP3. The values of the signals input through the input pins IP1 through IP3 of the LSI (B) 300b are similarly latched in the boundary register cells 104 in the LSI (B) 300b, and the latched signals output from the test data output terminal TDO. Then the tester checks the values of the signals. Finally, the LSI (A) 300a is set to output "1" from the output pin OP1, "0" from the output pin OP2 and "0" from the output pin OP3, and the signals input to the LSI (B) 300b through the input pins IP1 through IP3 are observed.
In this test, when the LSI (A) 300a is correctly connected to the LSI (B) 300b through the nodes A, B and C, the pattern of the signals input to the LSI (B) 300b through the input pins IP1, IP2 and IP3 are the same pattern as that of the signals output from the LSI (A) 300a through the output pins OP1, OP2 and OPS as is listed in Table 1.
When the node A is short-circuited with the power-supply potential (VDD), however, the signals cannot be correctly transferred from the LSI (A) 300a to the LSI (B) 300b as is listed in Table 2. In this case, the signal input to the LSI (B) 300b through the input pin IP1 is always "1", and hence, the short circuit of the node A to the power-supply potential can be detected.
When it is assumed that a current magnitude flowing in a transistor for outputting "1" is larger than that flowing in a transistor for outputting "0", that is, the output drive power of "1" is larger than that of "0" in the LSI (A) 300a, the signal pattern received by the LSI (B) 300b with a short circuit between the nodes A and B as in the case shown in Table 3 is "110", which is the logical OR between the outputs of the nodes A and B. On the contrary, when it is assumed that the output drive power of "0" is larger than that of "1" in the LSI (A) 300a, the signal pattern received by the LSI (B) 300b is "000", which is the logical product between the outputs of the nodes A and B.
In this manner, the input values to the LSI (B) 300b from the LSI (A) 300a are observed by utilizing the boundary scan cells. As a result, when the input signals take fixed values or are wired-OR or wired-AND, it can be determined that there is a defect between the LSIs caused by a short circuit, an open circuit or the like.
In such a conventional LSI, in the case of a complete short where, for example, the node A and a power supply line are soldered by mistake and the node A is completely short-circuited with the VDD, the signal observed at the input pin IP1 of the LSI (B) 300b is always "1" regardless of the value of the signal output from the output pin OP1 of the LSI (A) 300a. Therefore, the short circuit can be detected. But in the case of a slight short where, for example, a component or the like falls and lies on both the node A and the power supply line thereby to slightly short-circuit the node A with the VDD, the short sometimes cannot be detected.
In a case as shown in FIG. 4, where it is assumed that the N-channel transistor 2 in the output driver 107a has a general drive power as an LSI, and has an on resistance of, for example, approximately 30Ω, that the VDD is 3V, and that the input pin IP1 of the LSI (B) 300b has such a general TTL level as to determine an input voltage of 1.5V or more to be the high level. Under this condition, when there is a complete short circuit as mentioned above with a resistance of approximately 30Ω or less in the node A, the output voltage of the output pin OP1 of the LSI (A) 300a does not lower below 1.5V, and hence, the signal input to the input pin IP1 of the LSI (B) 300b is always "1", and is never "0". Therefore, the short circuit can be detected. In this conventional LSI, however, a slight short circuit as mentioned above of the node A with a resistance of several hundreds ohms cannot be detected.
Next, a test for a board mounting an LSI (C) 300c, an LSI (D) 300d, an LSI (E) 300e and an LSI (F) 800f as is shown in FIG. 8 by the boundary scan method will be described in this test, while a signal pattern "111" is being output from the LSI (C) 300c to the LSI (D) 300d, a signal pattern "010" is output from the LSI (E) 300e to the LgI (F) 300f, thereby checking whether a short circuit is caused between a node X which connects the LSI (C) 300c and the LSI (D) 300d, and a node Y which connects the LSI (E) 300e and the LSI (F) 300f. When the nodes X and Y are not short-circuited, the signal pattern "010" is correctly transferred from the LSI (E) 300e to the LSI (F) 30 of through the node Y. When the nodes X and Y are short-circuited, the signal pattern cannot be correctly transferred through the node Y. In this case, though the output drive power of the LSI (C) 300c is equal to that of the LSI (E) 300e, the signal patterns received by the LSI (D) 300d and the LSI (F) 300f are any of "111", "010" and "011" depending upon the variation in the drive powers of the respective LSIs caused by manufacturing variations when the outputs from the LSI (C) 300c and the LSI (E) 300e run against each other due to the short circuit between the nodes X and Y. As described above, the signal pattern resulting from the short circuit cannot be defined, it is difficult to accurately determine whether the node X is short-circuited with the node Y or with any other node. Moreover, since the signal pattern resulting from the short circuit is undefined, there is a possibility that a correct pattern is accidentally transferred in spite of the short circuit. In this case, the defect cannot be detected.
SUMMARY OF THE INVENTION
The present invention was devised to overcome the aforementioned problems. A first object of the invention is to provide a semiconductor device with a high detection accuracy for a defect which can detect a slight short or open circuit by switching an output drive power of an output buffer therein to a smaller drive power than that for the ordinary operation.
A second object of the invention is to provide a semi-conductor device which maintains reliability of the device by switching an output drive power to be smaller than that in an ordinary operation when executing a test of the devices whose connection being short-circuited thereby to prevent so much current to flow as to damage the device.
A third object of the invention is to provide a semiconductor device with an output buffer being able to switch an output drive power to be larger than that in an ordinary operation thereby to surely detect a short-circuit between a connection series with the device and another connection series with a device only having a drive power of an ordinary operation.
In carrying out our invention in one preferred mode, we utilize a semiconductor device comprising an output buffer for outputting a signal for the test, which has drive powers of at least two levels, the level being graded by a magnitude of a current flowing in a constituent element therein, means for switching the drive power to be smaller or to be larger when executing the test, and means for enabling the test signal input to the other device to be observed from the outside.
A fourth object of the invention is to provide a test method for a connection of semiconductor devices with a high detection accuracy for a defect in which patterns observed at LSIs in a plurality of connection series to which respectively input signals from other LSIs can be definite when the plurality of connection series are short-circuited.
In carrying out our invention in one preferred mode, we utilize a method for testing a connection of semiconductor devices comprising the steps of disposing, in one connection series, a semiconductor device comprising a buffer which has drive powers of at least two levels, the level being graded by a magnitude of a current flowing in a constituent element therein, whose larger drive power is larger than the drive power of said one semiconductor device in one of the other connection series, switching the drive power of said one semiconductor device in said one connection series to be larger when executing the test, and supplying test signals to said one semiconductor devices in the at least two connection series, respectively, to enable the test signals to be observed from the outside respectively input to said other semiconductor devices.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the configuration of a conventional LSI;
FIG. 2 is a circuit diagram of an output buffer in the conventional LSI;
FIG. 3 is a diagram of a board for illustrating a board test by the boundary scan method;
FIG. 4 is a circuit diagram showing the state when a short-circuit occurs in the conventional LSI;
FIG. 5 is a diagram of a board for exemplifying another conventional LSI testing method;
FIG. 6 is a block diagram showing the configuration of an LSI according to the invention;
FIG. 7 is a circuit diagram of an output buffer in the LSI shown in FIG. 6;
FIG. 8 is a circuit diagram showing the state when a short-circuit occurs in the LSI of the invention;
FIG. 9 is a circuit diagram of another output buffer in the LSI shown in FIG. 6; and
FIG. 10 is a diagram of a board for exemplifying an LSI test method according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described based on the accompanying drawings illustrating the examples thereof.
EXAMPLE 1
FIG. 6 is a block diagram of an LSI 100 of the invention manufactured in accordance with the standard for the boundary scan method. The LSI 100 supplies signals received through input pins IP1, IP2 and IP3 to an internal logic 102 via respective input buffers 101. The internal logic 102 performs a logical operation on the received signals. The LSI 100 further includes output buffers 105 and output pins OP1, OP2 and OP3. Each of the output buffers 105 has an enable terminal 20, that is, an input terminal for an enable signal that controls whether or not an output driver (described in detail below) is enabled to output data, and an output data terminal 21, that is, an input terminal for the data output by the output driver of another LSI. When the enable signal becomes significant, the output buffer 105 outputs the data received through the output data terminal 21 from the corresponding output pin OP1, OP2 or OP3 connected to a pad 22 provided for each output buffer 105. The output buffer 105 further has an EXTEST terminal 19, that is, an input terminal for an EXTEST signal (drive power selecting signal) 106. The EXTEST signal is negated in the ordinary operation of the LSI 100, but is asserted when an instruction decoder 103b in a boundary scan logic 105 described below decodes a switching instruction of a drive power of the output buffer 105, the instruction being included in an EXTEST instruction for testing the external of the LSI 100 or in a private instruction (equivalent instruction with the EXTEST instruction including the LSI external test instruction and the drive power switching instruction).
Further, the LSI 800 has, as terminals for test use only, an input pin TMS for a test mode selecting signal that is set in performing the board test, a test data input pin TDI, an input pin TCK for a test clock and a test data output pin TDO. The LSI 100 further has, as circuits for test use, the boundary scan logic 103 and boundary register cells 104. The boundary scan logic 103 includes an instruction register 103a for loading a test instruction such as the EXTEST instruction the private instruction or the like for testing the external of the LSI, and the instruction decoder 103b for decoding the instruction loaded in the instruction register 103a. The boundary register cells 104 are composed of flip-flops and provided between the respective input buffers 101 and the internal logic 102 and between the internal logic 102 and the respective output buffers 105 so as to correspond to the respective input pins IP1, IP2 and IP3 and the respective enable terminals 20 and output data terminals 21.
The boundary register cells 104 are connected in series to the boundary scan logic 103 so as to form a shift register. In testing a connection between the LSIs and the boundary scan logic 103 setting test data in the boundary register cells 104, the test data set in each boundary register cell 104 is shifted synchronously with the test clock input through the input pin TCK in a direction indicated by an arrow in the drawing. The boundary scan logic 103 outputs the values output by the boundary register cells 104 corresponding to the output data terminals 21 via the output buffers 105 through the output pins OP1 through OP3 to the outside. Or the boundary scan logic 103 makes the boundary register cells 104 to latch data input from another LSI through the input pins IP1 through IP3 and outputs the latched data to the outside of the LSI 300 via the output pin TDO so as to enable to observe the test result from the outside. The instruction decoder 103b asserts the EXTEST signal 106 when decoding the EXTEST instruction or the drive power switching instruction included in the private instruction.
In the ordinary operation of the LSI 100, an input signal is input to the LSI 100 through the input pins IP1, IP2 and IP3, transferred to the input buffers 101 and the boundary register cells 104 disposed between the input buffers 101 and the internal logic 102, and reaches the internal logic 102. An output signal from the internal logic 102 is transferred to the boundary register cells 104 disposed between the internal logic 102 and the output buffers 105 to reach the output buffers 105, and is output from the output pins OP1, OP2 and OP3.
FIG. 7 is a circuit diagram showing an exemplified configuration of an output buffer 105 of the LSI according to the invention shown in FIG. 6.
The output buffer 105 includes an output driver 105a formed from first CMOS transistors and second CMOS transistors. The first CMOS transistors are composed of a P-channel transistor 9 whose source is connected to a power supply and an N-channel transistor 11 whose source is grounded, and are turned on in the ordinary operation of the LSI 100 but are turned off in performing the board test. The second CMOS transistors are composed of a P-channel transistor 10 whose source is connected to a power supply and an N-channel transistor 12 whose source is grounded. The second CMOS transistors are set to have an output drive power of 1% of that of the output driver 105a in the ordinary operation, and are turned on both in the ordinary operation and in the board test.
The gate of the P-channel transistor 9 in the first CMOS transistors is connected to an output terminal of a three-input NAND gate 13 which receives a signal generated by inverting, by an inverter 17, the EXTEST signal input to the EXTEST terminal 19 to control the output drive power of the output driver 105a by turning on or off the transistors 9 and 11, the enable signal to the enable terminal 20, and a signal to the output data terminal 21. The gate of the N-channel transistor 11 is connected to an output terminal of a three-input NOR gate 15, which receives a signal generated by inverting the enable signal to the enable terminal 20 by an inverter 18, the signal to the output data terminal 21 and the EXTEST signal to the EXTEST terminal . The drains of the P-channel transistor and the N-channel transistor 11 are connected to the pad 22.
The gate of the P-channel transistor 10 in the second CMOS transistors is connected to an output terminal of a two-input NAND gate 14 receiving the enable signal to the enable terminal 20 and the signal to the output data terminal 21. The-gate of the N-channel transistor 12 is connected to an output terminal of a two-input NOR gate 18 receiving a signal generated by inverting the enable signal to the enable terminal 20 by the inverter 18 and the signal to the output data terminal 21. The drains of the P-channel transistor 10 and the N-channel transistor 12 are connected to the pad 22.
In the ordinary operation of the LSI 100, the EXTEST signal is negated to be at a low level, and hence, both the first CMOS transistors (i.e., the P-channel transistor 9 and the N-channel transistor 11) and the second CMOS transistors (i.e., the P-channel transistor 10 and the N-channel transistor 12) operate. Under this condition, when the enable signal input through the enable terminal 20 is at a high level and the signal from the output data terminal 21 is at a high level, the P-channel transistors 9 and 10 in the output driver 105a are turned on, and therefore, in assuming that the high level is "1", "1" is output from the output pin OP1, OP2 or OP3 via the corresponding pad 22. When the enable signal input through the enable terminal 20 is at a high level and a signal from the output data terminal 21 is at a low level, the N-channel transistors 11 and 12 in the output driver 105a are turned on, and therefore, "0" is output from the output pin OP1, OP2 or OP3 via the corresponding pad 22.
In the board test, the EXTEST signal is asserted to be at a high level. Therefore, the first CMOS transistors 9 and 11 are turned off, and the second CMOS transistors 10 and 12 alone operate. As a result, the output drive power of the output driver 105a lowers as compared with that for the ordinary operation.
The reason why the detection accuracy for defects or failures improves will be described with referring to FIG. 8 when applying the LSI of the invention being able to lower the output drive power from that in the ordinary operation comparing with the conventional LSI performing the board test with the same output drive power as the ordinary operation. FIG. 8 is an enlarged view of an output driver 105a in an LSI (A) 100a and a node A connecting an output pin OP1 of the LSI (A) 100a and an input pin IP1 of an LSI (B) 100b.
When the EXTEST instruction or the private instruction is loaded in the instruction register 103a in the boundary scan logic 103 in performing the board test, the EXTEST signal 106 output from the instruction decoder 103b is asserted responsive to decoding of the instruction by the instruction decoder 103b. When the EXTEST signal 106 is asserted to be at a high level ("1"), the first CMOS transistors 9 and 11, which Operate in the ordinary operation alone, are turned off, and merely the second CMOS transistors 10 and 12, which operate in the board test as well, output data.
In FIG. 8, the N-channel transistor 12 alone is turned on for outputting a signal at a low level as the output data. of the output driver 105a, and the other transistors 9, 10 and 11 are all turned off. The N-channel transistor 12, which is set to have the drive power of 1% of that of the output driver 105a for the ordinary operation, is assumed to have an on resistance of approximately 3kΩ. It is also assumed that the VDD is 3V, and that the input pin IP1 of the LSI (B) 100b has such a general TTL level as to determine the input voltage of 1.5V or more to be the high level.
When the node A is completely short-circuited with the VDD, the input pin IP1 of the LSI (B) 100b always receives "1" regardless of the value of the signal transferred from the output pin OP1 of the LSI (A) 100a. Accordingly, the short circuit can be detected with ease as in the conventional LSI.
When the node A is slightly short-circuited with the VDD so as to have a resistance of 3kΩ or less, the output voltage cannot lower below 1.5V since the on resistance of the N-channel transistor 12 is approximately 3kΩ. Therefore, in this case, a signal at a low level cannot be transferred, which enables to detect the short circuit. In this manner, the extent of a detectable short circuit is expanded to a resistance of 3kΩ in the present invention, while it is merely up to a resistance of 30Ω in the conventional LSI. Therefore, in the present LSI, a slight short circuit with a resistance of several hundreds ohms, which cannot be detected in the conventional LSI, can be detected. Thus, the detection accuracy improves.
Furthermore, the present LSI not only improves the detection accuracy in the board test but also suppresses a possible damage caused by the board test. In the conventional LSI, when a board including a short circuit is tested, the LSIs thereon can be damaged during the test because a current with the same magnitude as that in the ordinary operation flows through a route via a short-circuited part other than the inherent routes in the LSIs. In the present LSI, however, merely a small current flows in such a case because the drive power is small. Therefore, such a large current as to damage the LSIs would not flow even when the tested board includes a short circuit. Thus, the reliability of the LSIs can be maintained.
EXAMPLE 2
FIG. 9 is an enlarged circuit diagram of an output buffer according to another example of the present LSI. The like reference numerals are used to refer to like elements used in Example 1, and the description is omitted here. The LSI according to Example 2 has the same configuration as that of Example 1 except that the drive power of an output driver 105b is larger in the board test than in the ordinary operation in the output buffer of Example 2.
As is shown in FIG. 9, the output buffer 105 has an output driver 105b formed from first CMOS transistors and second CMOS transistors. The first CMOS transistors are composed of the P-channel transistor 9 whose source is connected to the power supply and the N-channel transistor 11 whose source is grounded, and are turned off in the ordinary operation of the LSI but are turned on in performing the board test. The second CMOS transistors are composed of a P-channel transistor 24 whose source is connected to a power supply and an N-channel transistor 25 whose source is grounded. The second CMOS transistors are set to have the same drive power as that of the first CMOS transistors, and operate both in the ordinary operation and the board test.
The gate of the P-channel transistor 9 in the first CMOS transistors is connected to the output terminal of the three-input NAND gate 13 which receives the EXTEST signal input to the EXTEST terminal 19 to control the output drive power of the output driver 105a by turning on or off the transistors 9 and 11, the enable signal to the enable terminal 20, and the signal to the output data terminal 21. The gate of the N-channel transistor 11 is connected to the output terminal of the three-input NOR gate 15 which receives a signal generated by inverting the EXTEST signal to the EXTEST terminal 19 by an inverter 23, a signal generated by inverting the enable signal to the enable terminal 20 by the inverter 18, and the signal to the output data terminal 21. The drains of the P-channel transistor 9 and the N-channel transistor 11 are connected to the pad 22.
The gate of the P-channel transistor 24 in the second CMOS transistors is connected to the output terminal of the two-input NAND gate 14 which receives the enable signal to the enable terminal 20 and the signal to the output data terminal 21. The gate of the N-channel transistor 25 is connected to the output of the two-input NOR gate 16 which receives a signal generated by inverting the enable signal to the enable terminal 20 by the inverter 18 and the signal to the output data terminal 21. The drains of the P-channel transistor 24 and the N-channel transistor 25 are connected to the pad
Next, the board test for detecting a short circuit between two connection series by using the present LSI having the larger drive power for the board test than that for the ordinary operation will be described referring to FIG. 10 and Tables 4 and 5. On the board to be tested is mounted an LSI (C) 200c and an LSI (D) 300d connected with a node X, and an LSI (E) 300e and an LSI (F) 300f connected with a node Y as is shown in FIG. 10, and the nodes X and Y are tested whether a short circuit occurs therebetween. Among these four LSIs, the LSI (C) 200c, which is one of the LSIs disposed in the upper stream of the current flow, is the LSI of this example having the larger drive power for the board test than that for the ordinary operation, and the LSI (D) 300d, the LSI (E) 300e and the LSI (F) 300f have a drive power of one level, namely have the same drive power both in the ordinary operation and in the board test.
In the board test by the boundary scan method, first, while the LSI (C) 200c is outputting "1" to the node X with the larger output drive power than in the ordinary operation, a signal is sent from the LSI (E) 300e to the LSI (F) 300f through the node Y. When there is no short circuit between the nodes X and Y, the signal is correctly transferred from the LSI (E) 300e to the LSI (F) 300f as is listed in Table 4. When there is a short circuit between the nodes X and Y, the signal cannot be correctly transferred from the LSI (E) 300e to the LSI (F) 300f through the node Y, but the signal pattern received by the LSI (F) 300f is the logical OR between the nodes X and Y as is listed in Table 5. Since the output drive power of the LSI (C) 200c for the board test is larger than that for the ordinary operation, the signal pattern transferred to the LSI (F) 300f is always the logical OR between the nodes X and Y as in Table 5 even when the output of the LSI (C) 200c having the same drive power as that for the ordinary operation runs against the output of the LSI (E) 300e. Accordingly, it can be easily detected that the node Y which is connected to the LSI (F) 300f having received different signal pattern from that output by the LSI (E) 300e being disposed in the upper stream of the current flow, is short-circuited with the node X.
In this manner, when the output drive power of one of the LSIs disposed in the upper stream of the current flow in two connection series is switched to be larger in the board test than in the ordinary operation, the detection accuracy for a short circuit can improve even when the other LSIs mounted together on the board to be tested are the conventional ones having the same drive power for the board test as that for the ordinary operation.
In such a board test using, as one of the LSIs disposed in the upper stream of the current flow, an LSI having the larger output drive power for the board test than that for the ordinary operation together with the other LSIs having the same output drive power as that for the ordinary operation, the following combinations of the LSIs are applicable in addition to the aforementioned combination, i.e., one of the LSIs disposed in the upper stream being the LSI having the larger output drive power to be used in the board test.
First, an LSI having only one level of drive power is used as the LSI disposed in the upper stream in one connection series, and the LSI disposed in the upper stream in another connection series is an LSI having a smaller drive power other than a drive power for the ordinary operation and the drive power thereof being switched to be smaller in the test. Secondly, both the LSIs disposed in the upper stream in the two connection series have a larger drive power other than a drive power for the ordinary operation, and, in the test, the drive power of the LSI disposed in the upper stream in one connection series is switched to be larger but that of the LSI disposed in the upper stream in the other connection series is switched to be the power for the ordinary operation. Thirdly, the LSI disposed in the upper stream in one connection series has a larger drive power other than the drive power for the ordinary operation, and the LSI disposed in the upper stream in the other connection series has a smaller drive power other than the drive power for the ordinary operation, and, in the test, the drive power of the former LSI is switched to be larger but that of the latter LSI is switched to be smaller.
By any of these combinations, the detection accuracy for a short circuit improves even when the conventional LSI having the ordinary drive power alone is mounted together on the board to be tested, by switching the drive power of the LSI(s) so that the output drive power of the LSI disposed in the upper stream in one connection series is larger than that of the LSI disposed in the upper stream in the other connection series.
Furthermore, although the LSI having either the larger or smaller drive power in addition to the drive power for the ordinary operation is described in Examples 1 and 2, the LSI can have both the larger and the smaller drive powers in addition to the drive power for the ordinary operation.
Further, although an output buffer is exemplified in the aforementioned examples, the output buffer can be replaced with an input/output buffer to attain the same effect in the same circuit configuration.
Moreover, although the larger drive power and the smaller drive power than that for the ordinary operation have merely one level in the examples, these drive powers can have two or more levels.
As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.
TABLE 1______________________________________LSI's ARE CORRECTLY CONNECTEDLSI (A) LSI (B)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE A 1 0 0 1 0 0NODE B 0 1 0 0 1 0NODE C 0 0 1 0 0 1______________________________________
TABLE 2______________________________________NODE A IS SHORT-CIRCUITED TO VDDLSI (A) LSI (B)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE A 1 0 0 1 1 1NODE B 0 1 0 0 1 0NODE C 0 0 1 0 0 1______________________________________
TABLE 3______________________________________NODES A AND B ARE SHORT-CIRCUITEDLSI (A) LSI (B)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE A 1 0 0 1 1 0NODE B 0 1 0 1 1 0NODE C 0 0 1 0 0 1______________________________________
TABLE 4______________________________________NODES X AND Y ARE NOT SHORT-CIRCUITED______________________________________LSI (C) LSI (D)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE X 1 1 1 1 1 1______________________________________LSI (E) LSI (F)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE Y 0 1 0 0 1 0______________________________________
TABLE 5______________________________________NODES X AND Y ARE SHORT-CIRCUITED______________________________________LSI (C) LSI (D)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE X 1 1 1 1 1 1______________________________________LSI (E) LSI (F)OUTPUTTED PATTERN INPUTTED PATTERNFROM OUTPUT PIN TO INPUT PIN______________________________________NODE Y 0 1 0 1 1 1______________________________________ | The invention provides a semiconductor device capable of switching drive powers of an output buffer thereof smaller than that for an ordinary operation for detecting even a slight short caused when a component is lying on a wiring pattern, thereby preventing damage of the device in the test even when the wiring pattern between the devices are short-circuited, and further provides a semiconductor device capable of switching drive powers of an output buffer thereof larger than that for an ordinary operation for surely detecting a short between a connection series including the above-mentioned semiconductor device and another connection series including a semiconductor device only having drive powers for the ordinary operation. The invention also provides a method for testing a connection between semiconductor devices capable of surely detecting a short between at least two connection series even on a board where a connection series is included with a conventional semiconductor device only having a drive power for the ordinary operation being mixed, by means of disposing a semiconductor device capable of switching drive powers of an output buffer in at least two levels in another connection series in the upper stream of the current flow, and switching the drive powers of the device to be larger or smaller. | 6 |
BACKGROUND
[0001] Providing software for services governed by a regulatory body may require adhering to a number of requirements that do not exist outside of the regulatory environment. Indeed, the cost (for example, in terms of money, time, or experience) of complying with such requirements often keeps some software suppliers from providing software to regulated markets.
[0002] The life sciences area is no exception. Regulatory markets involving, for example, clinical trials, toxicology, or environmental protection are often governed by regulatory bodies such as the FDA (Food and Drug Administration) or the EPA (Environmental Protection Agency) in the United States, and similar bodies in other countries. These agencies typically promulgate regulations that have the effect of making it difficult for software suppliers to provide software. For example, they may be unfamiliar with the regulations or may not have the infrastructure to provide software that complies with such regulations, and acquiring or developing such infrastructure may be too cost prohibitive.
[0003] In the clinical trials area, regulatory requirements coupled with legacy practices can make performing clinical trials difficult. Some of the legacy practices include submitting clinical trial results to regulatory authorities in paper form. One way that life sciences companies that perform clinical trials have tried to reduce their expense is to use software programs that make some submissions electronically. Regulatory authorities have promulgated rules and recommendations governing such electronic submissions, including electronic records and electronic signatures. In the United States, the FDA's rules that govern electronic records and electronic signatures are found in 21 CFR Part 11, which is designed to ensure that the electronic submissions are “trustworthy, reliable, and generally equivalent to paper records and handwritten signatures executed on paper.” 21 CFR §11.1. According to the FDA's Guidance for Industry regarding Part 11, Electronic Records; Electronic Signatures—Scope and Application (August 2003), “Part 11 applies to records in electronic form that are created, modified, maintained, archived, retrieved, or transmitted under any records requirements set forth in Agency regulations. Part 11 also applies to electronic records submitted to the Agency under the Federal Food, Drug, and Cosmetic Act (the Act) and the Public Health Service Act (the PHS Act), even if such records are not specifically identified in Agency regulations (§11.1).” The FDA has also provided other guidance related to software, for example, in its General Principles of Software Validation; Final Guidance for Industry and FDA Staff (January 2002).
[0004] Software suppliers may desire to offer software programs or applications to lessen the expense of clinical trials in particular, and to improve performance in other regulatory areas. But the information generated by these software programs, in addition to satisfying the regulatory agencies' requirements related to the data themselves and the processes followed to collect the data, must abide by those requirements. Navigating these requirements can be laborious, and making sure that software is compliant often dissuades suppliers from generating regulatory solutions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIGS. 1A-1C are various detailed block diagrams of a compliant software production system according to embodiments of the present invention; and
[0006] FIGS. 2-4 are flowcharts illustrating various embodiments of the present invention.
[0007] Where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.
DETAILED DESCRIPTION
[0008] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention. However, it will be understood by those of ordinary skill in the art that the embodiments of the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the present invention.
[0009] Embodiments of the present invention may be used in a variety of applications. For example, the techniques disclosed herein may be used in or with software in a variety of fields, clinical drug or device studies, and other projects in which software suppliers desiring to offer software solutions submit their software to a third-party compliance provider to ensure the software complies with regulations. A specific example may be in the field of custom metal-works manufacturing or custom orthodontic labs in which a practitioner may send a mold to a lab, the mold may then be used to make a device or object subject to quality control, and then the lab may test the mold pursuant to regulations and quality systems prior to returning it to the practitioner, a patient, or a customer.
[0010] In this specification, a “regulatory system” or “regulatory body” or “regulatory agency” means any type of rules-based system or rules-generating body, and is not limited to legal or law-based systems or bodies such as the FDA, EPA, or other governmental approval organizations. For example, a regulatory system, regulatory body, or regulatory agency could be a certification authority, a standard-setting organization, or other public or non-public organization that issues rules or requirements that software suppliers may desire to follow. Likewise, terms such as “rules,” “regulations,” and “requirements” may be used interchangeably. Also, the terms “software supplier” and “software application supplier” are used interchangeably in this specification and claims.
[0011] Software applications designed for regulatory systems are often required to be compliant with the various requirements of such systems. Compliance may mean that the software applications are (1) validated, (2) deployed in a validated fashion, e.g., proving-in that the application as deployed is in fact the application that was actually validated; (3) audited, including that those audits are tracked in a compliant fashion; and/or (4) monitored to ensure that the validated status is maintained. Of course, specific requirements are dependent on the situation—this is not intended to be limiting.
[0012] The present invention may be used to automate and prove compliance of software applications, including but not limited to those of smaller software suppliers who may lack the resources and knowledge to validate their own applications. It may also be used to open the regulatory software market to more regulatory software solutions. The techniques described herein may also create a standard or seal of approval in the specific regulatory industry for regulatory software compliance.
[0013] Reference is now made to FIGS. 1A-1C , which are various detailed block diagrams of a compliant software production system according to embodiments of the present invention. Broadly speaking, in FIG. 1A , a software application supplier, which may be a software vendor or regulatory software developer, may provide non-compliant software code and testable requirements to compliant software production system 10 , and compliant software production system 10 may produce regulatory-compliant software. Some regulatory systems may require that the software application supplier be accredited, e.g., that there be evidence of the supplier's (or the supplier's employees') education, training, or experience. Thus, in some embodiments, and depending on the compliance regulations, the software application supplier may already be accredited by, or confirmed to have appropriate accreditation by, the regulatory body, but in other embodiments, such accreditation may be performed by or confirmed by a compliant software producer. FIG. 1B shows that in one embodiment, compliant software production system 10 may be made up of one or more of four main blocks, validation block 20 , a block for proving-in the infrastructure 70 , a block to provide evidence of operational change management 80 , which may include providing a regulatory-compliant audit trail, and a continuous monitoring block 90 , which may ensure continued compliance with regulatory requirements such as response time, maintainability, and execution time. FIG. 1C shows that in one embodiment, validation block 20 may be made up of one or more of four blocks, test execution 30 , proving-in of software 40 , document generation for an auditor 50 , and electronic signing 60 .
[0014] FIGS. 2-4 are flowcharts illustrating various embodiments of the present invention. FIG. 2 is a flow diagram illustrating how a compliant software producer may validate and continuously monitor a software application supplier's software application according to an embodiment of the present invention. The supplier may develop a regulatory software application in any computer language. The application may, for example, be web-based or may operate in standalone mode on a variety of devices, such as mainframe, personal, or laptop computers, personal digital assistants (PDAs), tablet computers, cellphones, etc. In some instances, the application may be a service application that is not designed to interact with a user, but rather with other software. The supplier may also create testable requirements (which some may call scenarios), for example, in a human-readable format, that describe how its application may perform. Such testable requirements may also be known as scripts and may be written in a widely-used scripting language such as Cucumber. For example, a script may reflect that there should be two text-entry boxes on the login screen and, if a login fails, the next screen will display “login fail.” Or a requirement may be that for a given screen, selection of certain options will bring a user to a certain screen, whereas selection of other options would bring the user to another screen.
[0015] In operation 205 , the software application supplier may provide its application or source code to the compliant software producer, which may host the code and/or application in a hosted container, which may be a type of development or testing environment. In operation 210 , the supplier may also provide to the compliant software producer via API (application programming interfaces) the testable requirements for the application as discussed above. These inputs from the supplier may be digitally signed so that the compliant software producer knows that they have come from a particular software application supplier and have not been tampered with. In cases where this is not the first submission from a software application supplier, such as if the tests fail in operations 225 or 290 below, the digital signature may inform the compliant software producer that the corrected code comes from the same supplier. In operations 215 and 220 , the compliant software producer may use browser automation tools such as the Ruby programming language to run automated tests on the application to assess various functional requirements. These automated tests may interpret and execute the testable requirements against the supplier-provided application via the hosted container. Execution of the automated tests may be used, for example, to ensure that the application does what it claims to do. This may include automated tests that verify that the application behaves as specified. Such tests may include, but are not limited to, performance tests, review of design documents, installation qualification, operational qualification, performance qualification, code review for sufficient use of code styles, code coverage, cyclomatic (or conditional) complexity, and requirements testing or functional verification. Such tests may also include other tests, such as unit tests, if testable requirements for such tests were provided by the software application supplier in operation 210 . Although shown as two separate operations, depending on the programming language, interpretation in operation 215 and execution in operation 220 may both occur in the same operation, rather than sequentially.
[0016] Operation 225 asks whether the application passes the assessments, that is, if the supplier's application conforms to its testable requirements and passes the various functional requirements assessments as listed above. If not, then in operation 230 , information as to what failed is generated and may be provided to the supplier, in which case the supplier may, after addressing any problems, resubmit its application code and/or testable requirements to the compliant software producer in operations 205 and 210 . If the supplier's application conforms to its testable requirements, then in operation 235 validation documentation may be generated, including, for example, screen shots, code tracing, and validation certificate(s), as well as unit test results, if unit tests were performed in operation 220 . In operation 240 , the generated validation documentation may then be assembled into a validation portal for the supplier, including providing navigation links to the supplier. In operation 245 , the supplier may then review the validation documentation on the validation portal, and e-sign the application, that is, provide a digital or electronic signature. If the supplier is already accredited, the compliant software producer may verify such status based on the electronic signature provided by the supplier. The supplier's signature may then be sent back to the validation portal in operation 250 , and in operation 255 , the validation portal may be frozen such that no further changes may be made. At this point, the validation portal includes all the material an auditor would need to perform a compliance audit, so that the supplier itself need not have a quality system of its own.
[0017] After the software is frozen and operating, operation 290 asks whether the application is still operating per requirements, that is, that the application requirements are still being met. This may also include requirements that were not able to be fully tested during validation, such as uptime, response time, and throughput. If so, the system continuously asks the question again after a set amount of time. If the application is not meeting requirements, in operation 292 the compliant software producer may check the standard operating procedures (SOPs), which may include actions to be taken if or when the software has certain errors. One of the results of checking the SOPs may be to alert the software application supplier in operation 294 , in which case the supplier may review its application code and/or testable requirements and resubmit one or both to the compliant software producer in operations 205 and/or 210 . Operations 290 - 294 may be considered to be part of continuous monitoring block 90 or validation block 20 , depending on the regulatory system.
[0018] Besides the operations shown in FIG. 2 , other operations or series of operations are contemplated to validate a software application. Moreover, the actual order of the operations in the flow diagram is not intended to be limiting, and the operations may be performed in any practical order. For example, operation 294 may occur before operation 292 .
[0019] FIG. 3 is a flow diagram illustrating how a compliant software producer may prove-in a software application supplier's software application infrastructure according to an embodiment of the present invention. Although the supplier's regulatory application may be validated, it may not yet be able to be used in production for various reasons. For example, the infrastructure—the validated software plus whatever the software runs on—may also need to be validated. In operation 305 , the compliant software producer may provide one or more infrastructure choices to the supplier via a browser. In operation 310 , the supplier may then select from the infrastructure choices or may convey infrastructure requirements for its software. Infrastructure choices or requirements may include which language (Python, Ruby, C++, etc.) the web server runs, how powerful the server(s) are (e.g., how much throughput the servers may provide, how much capacity the servers may have, or how many end-users may need to be served), the types of databases used, and whether there is caching, load balancing, or other considerations related to hosting a supplier's application if it is web-based, or similar considerations if the application is deployed in a standalone mode. In operation 315 , the supplier may provide its software to the compliant software producer. The supplier may also save and retain its selection of infrastructure choices for future use, e.g., SQL Server and C++, or Ruby and MySQL.
[0020] Based on the supplier's choices, the compliant software producer may put together a package and deploy it on a network, for example, a local or wide area network or the Internet (“into the cloud”), and host it. In more detail, in operation 320 , the compliant software producer may use a hosting, provisioning, and deployment tool, also known as a recipe deployment tool, such as “Chef,” which is a deployment language hosted by Amazon®, to build the supplier's instances and, in operation 325 , deploy them (for example, put those instances on approved computing infrastructure and start running them). A “Chef Recipe” describes how to make a machine, and may then make the machine. This may create a virtual machine in Amazon's cloud.
[0021] At this point, all the materials needed for a regulatory-compliant application may be generated or logged. The compliant software producer may produce platform installation reports (PIRs) and other log information (traceability), which are proof that the software that is running in production is the same as what was run during validation. A PIR is the compliant software producer's proof that the application deployed is exactly what was to be deployed, and that the application works in production as previously validated (i.e., at operation 240 ). The proof or log(s) may go into the validation portal in operation 330 and may also go to the software application supplier in operation 335 . In operation 340 , the compliant software producer may compare the installation reports of the software that was validated in operation 240 and the software that is running in production in order to prove that what was validated is what is running in production. Besides the operations shown in FIG. 3 , other operations or series of operations may be used to prove-in the infrastructure of a software application. Moreover, the actual order of the operations in the flow diagram is not intended to be limiting, and the operations may be performed in any practical order.
[0022] FIG. 4 is a flowchart illustrating how a compliant software producer may provide an audit trail for a supplier's software infrastructure according to an embodiment of the present invention. Such an audit trail may include evidence of operational change management. After validation and proving-in of infrastructure, audits of applications that are running in production may be required for compliance with certain rules of a regulatory system. To provide such evidence of operational change management, in operation 405 , the supplier may transmit to an audit service all of the audits of the working applications. This audit service may be operated by the compliant software producer. The audit service may then acknowledge receipt of the audit in operation 410 . In operation 415 , the audit service may store the audits and, in operation 420 , provide indexing for lookup. In operation 425 , the audit service may guarantee that the audits have a number of attributes. Common attributes include that the audit is unchangeable, attributable, time-stamped (possibly based on an atomic clock), retrievable, and captures the reasons for change as required. The audit service may guarantee that the audit (or audit trail) will not disappear, and may replicate such audit or audit trail. Besides the operations shown in FIG. 4 , other operations or series of operations may be used to provide auditing services for a software application. Moreover, the actual order of the operations in the flowchart is not intended to be limiting, and the operations may be performed in any practical order.
[0023] The previous embodiments are described in the setting of creating compliant software to be used in regulatory systems, including clinical trials for drugs or medical devices, trials for toxicology studies, and EDMS (electronic document management system). It is understood, however, that embodiments of the invention can be used in other fields involving compliance with rules in which software suppliers may wish to offer a software application, but it is not cost effective for them to make sure the application is compliant with rules promulgated by organizations such as public or private certification authorities, standards-setting organizations, or other rule-setting bodies.
[0024] The blocks shown in FIGS. 1A-1C are examples of modules that may comprise compliant software production system 10 , and do not limit the blocks or modules that may be part of or connected to or associated with compliant software production system 10 . For example, as mentioned before, validation block 20 may be visualized as being made up of test execution block 30 , proving-in of software block 40 , document generation for an auditor block 50 , and electronic signing block 60 . But those blocks indicate functions that may be performed while validating a supplier's software application, and are not rigid descriptions of functions required for validation. In addition, some regulatory systems may not require all of the blocks shown in FIGS. 1A-1C or in the same order, so, for example, software may be regulatory-compliant after completing just validation and proving-in of infrastructure, while providing evidence of operational change management may not be needed or performed or may be performed as part of a post-approval process. Similarly, continuous monitoring may not be required by the regulatory authority, may be performed as part of a post-approval process, or may be performed as part of a validation process. The blocks in FIGS. 1A-1C may generally be implemented in software or hardware or a combination of the two.
[0025] An example of an application that may be validated by use of the present invention would be a system that connects, via application programming interface(s) (API) to a hosted electronic health records (EHR) system to extract patient data and insert them into a clinical trial record. Such a system may make use of the platform data transport, clinical data management, and auditing functions of the invention. Another example of an application that may be validated by use of the present invention would be a system that receives data from a central lab, enters it into a clinical trial record but also performs statistical analysis on the data to identify correlations and trends in the data, surfacing that analytics only to key users (e.g., so as not to unblind the trial). Such a system may make use of platform data transport and transformation capabilities, auditing, clinical data management, data-permissions/visibility framework, graphing, and report generation and display. Yet another example of an application that may be validated by use of the present invention may be a system that converts data entry prompts and responses to and from Braille terminals so that electronic patient reported outcomes studies can be performed in blind and partially sighted populations. Such a system may make use of APIs to exchange data via the Internet, study metadata services (to read question prompts), and clinical data management and auditing functions for the entry of the data.
[0026] Some of the benefits of the present invention are that software application suppliers desiring to offer software solutions to be used in regulatory activities do not need to be well-versed in the regulatory agency's rules regarding electronic solutions or in rules regarding validation and testing of software and software infrastructure. This may be of a benefit to smaller software suppliers who have innovative applications to be used in the regulatory industry, but lack the training, manpower, resources, or economic means to learn and abide by the regulatory agency's rules regarding electronic solutions. The present invention also provides a platform and verified infrastructure with which the software can be used. The supplier provides to a compliant software producer the code and certain testable requirements that the software supplier wants to execute, and the compliant software producer validates the code by testing it and executing the testable requirements and, once the application works, freezing the application's development. Then the compliant software producer proves-in the infrastructure in which the application will be used according to the compliance rules. The compliant software producer, with knowledge of the auditing requirements, may then provide auditing services, such as evidence of operational change management and audit trails, to the software supplier that comply with those rules as well as continuous monitoring of the validated status. In addition, a compliant software producer may offer multi-region backups, redundant live data (mirroring), and other services to make data 100% available. In all of these cases, the supplier's software code need not be viewed by human eyes, and thus can remain the intellectual property of the supplier.
[0027] Compliant software production system 10 may be implemented on a network, for example, over the Internet as a cloud-based service or hosted service, which may be accessed through a standard web service API. This means that the compliant software production system can perform a regulatory-compliant validation of a software application and then issue all of the appropriate regulatory documentation. Implementation may also include offering a platform as a service that hosts the software application and is rule compliant.
[0028] The present invention differs from other systems that may host or offer software for sale. For example, those systems may have acceptance criteria, but do not (automatically) validate such software. Those systems may lack validation portals, may not provide proofs of quality, may not enforce minimum training requirements, may not provide ongoing testing of requirements via monitoring, and may not provide audit functions. The present invention may also provide digital signature verification of the software.
[0029] Aspects of the present invention may be embodied in the form of a system, a computer program product, or a method. Similarly, aspects of the present invention may be embodied as hardware, software or a combination of both. Aspects of the present invention may be embodied as a computer program product saved on one or more computer-readable media in the form of computer-readable program code embodied thereon.
[0030] For example, the computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example, an electronic, optical, magnetic, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof.
[0031] A computer-readable signal medium may include a propagated data signal with computer-readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. A computer-readable signal medium may be any computer-readable medium that is not a computer-readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
[0032] Computer program code in embodiments of the present invention may be written in any suitable programming language. The program code may execute on a single computer, or on a plurality of computers. The computer may include a processing unit in communication with a computer-usable medium, wherein the computer-usable medium contains a set of instructions, and wherein the processing unit is designed to carry out the set of instructions.
[0033] The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. | A system for producing a clinical trial software application includes a processor, comprising a validation service and an audit service, and a platform, configured to prove-in an infrastructure on which the software application operates. The software application operating on the infrastructure is the same as the software application previously validated in a validation portal. The proving-in of the infrastructure comprises receiving infrastructure requirements from a software application supplier, building the software application supplier's instances, logging an installation report to the validation portal, and comparing the log to the frozen, validated software in the validation portal. The validation service is configured to validate the software application, freeze the validated software application in the validation portal, and generate documentation that satisfies compliance rules for the clinical trial software application. The validation service receives software code, testable requirements, and test results from a software application supplier and generates documentation regarding the validation of the software application. The audit service is configured to provide evidence of operational change management for a regulatory agency according to compliance rules of the regulatory agency. A method for producing regulatory-compliant software is also described and claimed. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ingot support device a slicing apparatus which is used to slice out a thin wafer from the end face of a cylindrical ingot in a semiconductor wafer manufacturing process.
2. Description of the Related Art
In a slicing apparatus, the upper end of a cylindrical ingot is held by a hold mechanism provided in the slicing apparatus by use of an adhesive or the like and, while the lower end portion of the ingot is being pressed against the internal peripheral edge of a blade revolving at high speeds, the ingot lower end portion is sliced out into a thin disc-shaped wafer by the internal peripheral edge blade. In the above-mentioned slicing apparatus, the ingot that is held in a cantilevered manner by the hold mechanism suffers a slicing resistance, that is, the upper end portion of the ingot that is held by the hold mechanism is given a flexing pressure, so that the ingot is caused to move back in a direction away from the above-mentioned blade edge. The flexing pressure is small at the beginning of slicing, gets gradually larger as the slicing advances, and gets small again in the neighborhood of the end of the slicing. Therefore, there is a problem that the sliced surface of the wafer may not be a flat surface but be a curved one. In order to solve this problem, there has been proposed a technique to hold the lower end portion of the ingot, namely, the portion thereof disposed close to the blade edge in a fixed manner. For example, this technique is disclosed in Japanese Utility Model Publication No. 54-1961, No. 50-1310 and the like. In the former model, in the inner tip end of a cylindrical holder there is provided a structure which is capable of vacuum adsorption of an ingot so as to fix and hold the end portion of the ingot. In the latter, there is provided a structure to further press the ingot end portion, which is located along a holding table, toward the holding table so as to fix and hold the ingot end portion. In either of these structures, however, since the ingot is fixed and held by applying partial loads thereto, the hold surface of the ingot upper end is also affected by the loads, as in the above-mentioned slicing resistance, so that a pressure is given to the ingot to peel off the adhesive surface thereof. Therefore, in order to avoid the above-mentioned drawbacks, the ingot must be set with high accuracy, resulting in the more troublesome and complicated setting operation.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the drawbacks found in the above-mentioned prior art support devices.
Accordingly, it is an object of the invention to provide an ingot support device which has no ill effects on the adhesive surface of an ingot.
In order to attain the above object, according to the invention, there is provided a slicing apparatus which comprises: a rotary blade for slicing a cylindrical ingot into a disc-shaped wafer; a first moving mechanism movable in an ingot slicing direction orthogonal to the axis of the ingot; a second moving mechanism for holding one end of the ingot, the second moving mechanism being supported by the first moving mechanism such that it is free to move in the axial direction of the ingot and an ingot support device provided in the first moving mechanism for contact supporting the ingot at a position substantially opposite to the position of the ingot to be sliced by the blade.
In the present invention, when slicing the ingot, the ingot support device is used to support the ingot at a position opposite to the position of the ingot to be sliced by the blade against a reaction force which is produced in slicing, thereby avoiding ill effects on the adhesive layer of the ingot while the ingot is being sliced.
BRIEF DESCRIPTION OF THE DRAWINGS
The exact nature of this invention, as well as other objects and advantages thereof, will be readily apparent from consideration of the following specification relating to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof and wherein:
FIG. 1 is a front view of the general structure of an ingot support device for use in a slicing apparatus according to the invention;
FIG. 2 is a section view taken along the line II--II in FIG. 1, illustrating a first embodiment of an ingot support device according to the invention;
FIG. 3 is a section view of a second embodiment of an ingot support device according to the invention; and,
FIG. 4 is a section view of a third embodiment of an ingot support device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
Detailed description will hereunder be given of the preferred embodiments of an ingot support device for use in a slicing apparatus according to the present invention with reference to the accompanying drawings.
Referring first to FIG. 1, there is shown an outline of a slicing apparatus in which there is provided a bowl-shaped body of rotation 1 having an open upper surface, an internal peripheral edge blade 2 is arranged on the upper edge of the rotation body 1, and an ingot 3 is erected in the central bore thereof. In the slicing apparatus, in the above-mentioned condition, the blade 2 is rotated at a high speed and the ingot 3 is pushed in the right direction in FIG. 1 against the blade 2, so that the lower end face of the ingot 3 is sliced into a thin wafer. In this case, the ingot 3 is held at the upper end thereof and the ingot is then moved up and down as well as right and left to be cut. Here, the upward and downward movements of the ingot are a pitch feed to slice out the wafers one by one and for this pitch feed there is provided a moving mechanism 4 which is conventionally well known and has a screw driven mechanism. Also, the right and left movements of the ingot is a feed to press the ingot against the blade edge or retreat it from the blade edge and, for this, purpose, there is provided a right and left moving mechanism 5 which includes the above-mentioned upward and downward moving mechanism 4. That is, the upward and downward moving mechanism 4 is supported by the right and left moving mechanism 5 in such a manner that it is free to move upwardly and downwardly, and the right and left moving mechanism 5 is supported by a main body (not shown) of the slicing apparatus in such a manner that it is free to move right and left.
In FIG. 2, a bar base 10 is mounted to the right and left moving mechanism 5 by a screw 9. The bar base 10 can be mounted at an arbitrary height position with respect to the right and left moving mechanism 5 by loosening the screw 9. First and second bars 11 and 12 are respectively extending from the bar base 10 and the respective leading ends thereof are connected by a third bar 13. The bar base 10 and these three bars cooperate to form a quadrilateral frame in such a manner that the ingot 3 can be surrounded by the quadrilateral frame. In this structure, the bar base 10 and second bar 12 can be rotated mutually by means of a pin 14 and there is provided a pin 15 between the first and third bars 11 and 13, so that they are rotatable to each other. Also, the first bar 11 can be freely slided relative to the bar base 10 by loosening screws 10a, 10a and the second bar 12 can be freely slided relative to the third bar 13 by loosening nuts 13a, 13a. Due to such construction, the size of the quadrilateral frame can be adjusted according to the diameter of the ingot 3.
The second bar 12 is divided into two sections and a lock cylinder 16 is interposed between the two sections. Also, the third bar 13 is adapted to touch and support the ingot 3 from the opposite side of the cutting side thereof to prevent the ingot from escaping due to the cutting or slicing resistance. On the inside wall of the third bar 13 there is provided a contact portion 17 for contact with a slice base 3a which is attached to the ingot 3.
For the above-mentioned lock cylinder 16, there have been used various types of lock cylinders and one of them has such a mechanism that a piston disposed within the cylinder is moved by controlling pressurized air and is locked (clamped) at a desired position with respect to the cylinder.
Referring to the operation of the lock cylinder, if the pressurized air is supplied through an air supply hole (not shown), then the piston in the cylinder is moved to push out, for example, a piston rod which forms one section of the second bar 12. As a result of this, in the above-mentioned quadrilateral frame that is composed of four bars, the second bar 12 is extended to rotate the third bar 13 clockwise about the pin 15, so that the contact portion 17 is caused to widen a space from the ingot (slice base 3a). Next, if the air supply is stopped and the cylinder 16 is operated in reverse, then the piston is moved in the return direction thereof to bring the contact portion 17 into contact with the ingot 3 (slice base 3a). On detection of this contact, if the internal lock mechanism is operated, then the second bar 12 is locked and the contact portion 17 maintains its contact with the ingot 3. Then, in this condition, if the ingot 3 is moved in the direction of the blade 2, then the ingot 3 is fixed at the upper and lower ends thereof so that the ingot 3 can be sliced properly.
On completion of slicing of a first wafer, the locking state of the lock cylinder 16 is removed, the contact portion 17 is parted away from the ingot 3 by a similar operation to the above-mentioned one, and the upward/downward moving mechanism 4 is driven to move the ingot 3 down by a pitch for the next slicing. The operation of the lock cylinder 16 may be automatically controlled by a signal which indicates the completion of slicing of the wafer.
As described above, according to the invention, when the slicing of a piece of wafer is completed, then the third bar 13, which is in contact with the slice base 3a of the ingot 3, is moved away from the slice base 3a to thereby render the ingot 3 free, so that the ingot 3 is then moved down by one pitch of the wafer. After then, the contact portion 17 of the third bar 13 is again brought into contact with the ingot 3 and, in this state, the ingot 3 is locked by the lock cylinder 16. Thanks to this, the end portion of the ingot 3 can be contacted and supported from the opposite side of the slicing thereof without applying excessive loads and thus the wafer can be sliced out from the ingot end portion regardless of the magnitude of the slicing resistance. Also, according to the present invention, the ingot lower end portion can be supported without paying special attention to the holding state of the ingot and, therefore, a highly efficient device can be provided.
Referring now to FIG. 3, there is shown a second embodiment of an ingot support device according to the invention.
In FIG. 3, there is arranged an ingot support arm 21 which extends from a base 10 in the direction of an ingot 3. The ingot support arm 21 is bent at the middle portion thereof and is divided into two sections; one is a base-side arm section 21a and the other is a leading-end-side arm section 21b. In the base-side arm section 21a there is provided a lock cylinder 23 which is similar to the cylinder in the first embodiment and in the arm section 21b there is provided an ingot contact portion 22 which allows the arm to come in contact with the ingot 3 from the opposite side of slicing of the ingot 3. The support arm 21 is used to prevent the escape of the ingot 3 and thus the contact position of the contact portion 22 with the ingot may be a slice base 3a attached to the ingot. However, from the viewpoint of effects, it is preferred that the contact portion 22 is able to come into contact with the ingot in the opposite surface portion of a reaction which is produced due to the slicing resistance of an internal peripheral edge blade 2, that is, a vector direction position which is obtained from the push direction of the ingot 3 and the rotational direction of slicing of the internal peripheral edge blade, for example, as shown in FIG. 3, a position which is shifted left slightly from the slice base 3a.
Since in the base-side arm 21a there is provided the lock cylinder 23 as discussed before, a portion of the base-side arm 21a is formed by a rod which is connected to a piston (not shown) within the lock cylinder 23.
Referring to the operation of the cylinder 23, if a pressurized air is supplied through an air supply hole (not shown), then the piston within the lock cylinder 23 is moved to push out the piston rod (the base-side arm section 21a). As a result of this, the support arm 21 is caused to extend so that the contact portion 22 is moved away from the ingot 3. Next, if the air supply is stopped and the cylinder is operated reversely, then the piston is moved in the return direction thereof to thereby bring the contact portion 22 into contact with the ingot 3 again. After such contact, if a lock mechanism within the lock cylinder is put into operation, then the leading-side arm section 21b can be locked in position and the contact portion 22 can be stopped while it is in contact with the ingot 3. Then, in this condition, if the ingot 3 is moved in the direction of the ingot 3, then the ingot 3 can be fixed in the upper and lower end portions thereof for slicing.
Referring now to FIG. 4, there is shown a third embodiment of an ingot support device according to the invention. In the third embodiment in FIG. 4, the same or similar parts as in the first embodiment of the invention in FIG. 2 are given the same reference characters and the description thereof is omitted here.
In the third embodiment, the magnitude of the slicing resistance of the ingot 3 applied to a moving mechanism 5 is measured and the measured value is used to represent the cutting quality of the blade 2.
A piezo-electric element 25 is interposed between a contact portion 17 and a bar 13 and the variations of the output of piezo-electric element 25 are considered as the variations of the slicing resistance. The values of the slicing resistance output increase gradually from zero at the time of the first contact of the ingot 3 with the blade 2 and then decrease gradually down again to zero. In other words, when the cutting or slicing quality of the blade is lowered, then the slicing resistance acts as a pressure in the opposite direction to the slicing direction so that the peak value of the detection values rises. It should be noted here that as the ingot support device, there are available various types of devices such as the first embodiment, second embodiment and the like, provided that the device can prevent the ingot 3 from escaping or retreating in the opposite direction to the slicing direction. The third embodiment of the invention can be employed in any types of devices and in the third embodiment the piezo-electric element 25 is disposed in the portion of the device where pressure is given.
As has been described above, according to the third embodiment of the invention, since the slicing resistance can be detected directly as a numeral value, the blade can be controlled effectively and a simple and inexpensive device can be provided.
It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the invention is to cover all modifications, alternate constructions and equivalents falling within the spirit and scope of the invention as expressed in the appended claims. | A slicing apparatus is disclosed which slices a cylindrical ingot into disc-shaped wafers by a rotating blade. The slicing apparatus includes an ingot support device which is used to contact support the ingot at a position opposed to the position of the ingot to be sliced by the blade. Therefore, a rection force which is produced in the ingot slicing can be supported by the ingot support device, thereby eliminating any ill effects on the hold surface of the ingot. | 8 |
This is a division of application Ser. No. 817,668 filed Jan. 10, 1986, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to an unsaturated polyester resin composition for treating cathode-ray tubes.
A method for adhering a cathode-ray tube and front glass to each other generally comprises, as shown in the attached drawing, surrounding and holding, in contiguity with a face-plate portion 2 of a cathode-ray tube 1, front glass 3 having the same curvature and substantially the same size as the face-plate portion 2 with a tape 4 at a very short distance from the face-plate portion, filling this gap with a resin composition 5 such as epoxy resin composition, unsaturated polyester resin composition or the like, and then curing the resin composition.
Conventional epoxy resin compositions and unsaturated polyester resin compositions for adhering a cathode-ray tube and front glass to each other have both merits and demerits, and in the existing circumstances, there has not yet been obtained any resin composition having both characteristics and workability which are satisfactory as those of the resin composition for adhering a cathode-ray tube and front glass to each other.
For example, when an epoxy resin composition is used, it has a high adhesive strength and hence is advantageous for adhering front glass to a face-plate portion, but since it has a considerable coloring property, it is not preferable for use in a cathode-ray tube in which color is regarded as important, such as a color cathode-ray tube. Moreover, in the case of a cathode-ray tube having a high added value in itself such as a color cathode-ray tube, its recovery is also regarded as important, and when an epoxy resin is used, it has a high adhesive strength, so that the face-plate portion tends to be injured at the time of removing the front glass, therefore it is substantially impossible to peel off the glass.
Moreover, epoxy resin compositions have a higher viscosity than unsaturated polyester resin compositions and hence are disadvantageous in that foams sucked at the time of mixing with a curing agent or casting the resin are difficult to remove. Furthermore, since epoxy resins increase rapidly in viscosity immediately after being mixed with a curing agent, their period of usability at casting is very short, and for carrying out operations smoothly, special mixing and casting apparatus are needed; thus they are very poor in workability.
On the other hand, when an unsaturated polyester resin composition is used, its viscosity generally is as relatively low as several poises, so that its mixing with a curing agent and its casting into the gap between the face-plate portion of a cathode-ray tube and front glass are easy, and because of its low viscosity, it is advantageous, for example, in that it is easily defoamed at the time of mixing or casting. However, if the proportion of the curing agent of several percent based on the unsaturated polyester resin composition is different from the predetermined condition, distortion is locally caused at the time of curing. This cure distortion results in lens effect, so that when the cathode-ray tube is operated, a striped pattern, luminant spots and the like appear on a screen.
Since these striped pattern and luminant spots impare the value of the product, sufficient care should be taken in the mixing proportion of the curing agent.
The cure distortion is caused also by rapid heating or temperature unevenness of a curing oven, therefore temperature control and the like should be sufficiently carried out.
Unsaturated polyester resin compositions involve many problems in their production as described above, but they are advantageous in that they have a low viscosity and hence is easily defoamed, that they are hardly colored and hence excellent in transparency, and that the cathode-ray tube can be recovered relatively easily. However, they are disadvantageous in that since they are poor in adhesive strength, they peel off from the face-plate portion or the front glass portion when the cathode-ray tube is operated for a long period of time.
SUMMARY OF THE INVENTION
An object of this invention is to remove the surface defects, i.e., the defects in the prior art while making the most of the advantages of unsaturated polyester resins and provide a resin composition for treating cathode-ray tubes which has low viscosity and high transparency and adhesiveness and is free from occurrence of the surface defects due to distortion at the time of curing, etc.
This invention provides a resin composition for treating cathode-ray tubes obtained by adding 0.5 to 10 parts by weight of maleic anhydride to 100 parts by weight of an unsaturated polyester resin composition comprising
(I) an unsaturated polyester obtained by reacting as an acid component an unsaturated dibasic acid and/or an acid anhydride thereof, and if necessary one or more other polybasic acids and/or acid anhydrides thereof, with an alcohol component and having a molecular weight of 500 to 8000 per unsaturated group in the polyester
(II) a sytrene monomer and/or a derivative thereof, and
(III) at least one polymerizable unsaturated compound selected from the group consisting of
(i) acrylonitrile, itaconic acid and citraconic anhydride,
(ii) monoesters of unsaturated dibasic acids and diesters of unsaturated dibasic acids, and
(iii) acrylic acid, methacrylic acid and their derivatives, and
the component (I) being dissolved in the components (II) and (III) in the range of
(b)/{(a)+(c)}=1/10 to 10/1
wherein (a) is the number of unsaturated groups in the component (I); (b) is the number of unsaturated groups in the component (II); and (c) is the number of unsaturated groups in the component (III).
BRIEF DESCRIPTION OF THE DRAWING
The attached drawing is a sectional schematic illustration of an explosion-proof cathode-ray tube.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The unsaturated dibasic acid and/or an acid anhydride thereof used as the main constituent of the acid component for preparing the unsaturated polyester (I) includes maleic acid, fumaric acid, itaconic acid, citaraconic acid, maleic anhydride, etc. These may be used alone or as a mixture thereof.
The acid component can, if necessary, contain a polybasic acid. Examples of the polybasic acid include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, trimellitic anhydride, succinic acid, azelaic acid, adipic acid, sebacic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, anthracenemaleic anhydride adduct, rosin-maleic anhydride adduct, Het Acid and anhydride thereof, chdlorinated polybasic acids such as tetrachlorophthalic acid, tetrachlorophthalic anhydride and the like, halogenated polybasic acids such as tetrabromophthalic acid, tetrabromophthalic anhydride, etc. These may be used as a mixture thereof.
Further, the acid component may also contain 3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride or 3,6-endomethylene-1,2,3,6-tetrahydrophthalic acid.
3,6-Endomethylene-1,2,3,6-tetrahydrophthalic anhydride is obtained for example, by pyrolyzing dicyclopentadiene at 170° to 180° C. into cyclopentadiene, and subjecting it to Diels-Alder reaction with maleic anhydride at 20° to 40° C. for 2 hours. Such a compound is commercially available under the trade name of HIMIC anhydride manufactured by Hitachi Chemical Company, Ltd. ##STR1##
3,6-Endomethylene-1,2,3,6-tetrahydrophthalic acid is obtained by using maleic acid in place of the above maleic anhydride. These compounds are well known.
As the alcohol component, there can be used dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, triethylene glycol, neopentyl glycol and the like; trihydric alcohols such as glycerin, trimethylolethane, trimethylolpropane and the like; tetrahydric alcohols such as pentaerythritol and the like; etc. There can also be used halogenated alcohols such as chlorides, bromides and the like of the various alcohols described above.
A process for producing the unsaturated polyester by reacting the aforesaid acid component with the aforesaid alcohol component is conducted mainly by condensation reaction and by elimination of low-molecular-weight compounds produced by the reaction of the two components such as water from the system.
As a reactor for carrying out this reaction, there is selected one which is inert toward the acid component, such as a reactor of glass, stainless steel or the like, and it is preferable to use a reactor equipped with a stirrer, a fractionating device for preventing the alcohol component from being distilled out azeotropy of water and the alcohol component, a heating device for raising the temperature of the reaction system, a temperature-controlling circuit for the heating device, and a device for introducing nitrogen gas or the like.
As to the reaction conditions, it is preferable to carry out the reaction at a temperature of 150° C. or higher at which the reaction rate is sufficiently high. For preventing coloring by oxidation reaction at high temperatures, a reaction temperature in the range of 160° C. to 210° C. is more preferable.
For preventing side reactins due to oxidation at high temperatures, it is preferable to carry out the synthesis while introducing an inert gas such as nitrogen, carbon dioxide or the like.
The reaction is allowed to proceed by heating the system composed of a mixture of the acid component and the alcohol component, and eliminating produced low-molecular-weight compounds such as condensation water from the system. The elimination is conducted preferably by spontaneous distilling-out by induction of an inert gas or distilling-out under reduced pressure. When the low-molecular-weight compounds to be distilled out have a high boiling point, a high vacuum is needed.
Further, for accelerating distilling-out of the low-molecular-weight compounds such as condensation water, it is also possible to add a solvent such as toluene, xylene or the like to the system to conduct spontaneous distilling-out.
The degree of progress of the reaction can be known generally by, for example, measuring the amount of a distillate produced by the reaction, quantitatively determining the terminal functional group, or measuring the viscosity of the reaction system.
The unsaturated polyester used in this invention has a molecular weight of 500 to 8000, preferably 1000 to 4000 per unsaturated group.
Such an unsaturated polyester can be produced by a well-known process by adjusting the mixing ratios of the starting materials.
When the molecular weight per mole of unsaturated group of the unsaturated polyester is less than 500, the crosslinking density of the resulting cured product of resin is increased. Accordingly, the shrinkage percentage of the resin is increased and the cured product of resin becomes inflexible, therefore peeling-off from the front glass or the face-plate portion is caused.
When the molecular weight per unsaturated group of the unsaturated polyester exceeds 8000, no sufficient crosslinking occurs at the time of curing the resin. Therefore, copolymerization of only the styrene monomer and/or a derivative thereof occurs, so that the cured resin becomes whitely turbid, and hence the cathode-ray tube cannot be used as an article of commerce. Further, since no sufficient crosslinking occurs, a lowering of adhesive strength to the front glass or the face-plate portion of cathode-ray tube is caused under the conditions of high temperature and humidity (85° C., 90% R.H.) and is responsible for peeling-off.
The styrene monomer and/or a derivative thereof (II) in which the unsaturated polyester (I) thus obtained is dissolved include styrene, chlorostyrene, dichlorostyrene, p-methylstyrene, α-methylstyrene, vinyltoluene, divinylbenzene, etc. These are used alone or in combination.
As the polymericable unsaturated compound (III), there is used at least one member selected from the group consisting of (i) acrylonitrile, itaconic acid and citraconic anhydride.
As the polymerizable unsaturated compound (III), there can also be used at least one compound selected from the group consisting of (ii) monoesters and diesters of unsaturated dibasic acids.
As the monoesters and diesters of unsaturated dibasic acids, there can be used, for example, various esters such as monomethyl fumarate, dimethyl fumarate, monomethyl maleate, dimethyl maleate, monoethyl fumarate, diethyl fumarate, monoethyl maleate, diethyl maleate, monopropyl fumarate, dipropyl fumarate, monopropyl maleate, dipropyl maleate, monobutyl fumarate, dibutyl fumarate, monooctyl fumarate, dioctyl fumarate, monomethyl itaconate, dimethyl itaconate, diethyl itaconate, monoethyl itaconate, monobutyl itaconate, dibutyl itaconate, monopropyl itaconate, dipropyl itaconate and the like.
These esters can be used alone or in combination.
As the polymerizable unsaturated compound (III), there can also be used at least one compound selected from the group consisting of (iii) acrylic acid, methacrylic acid and their derivatives.
As the derivatives of acrylic acid and methacrylic acid, there can be used, for example, allyl acrylate, benzyl acrylate, butyl acrylate, ethyl acrylate, methyl acrylate, propyl acrylate, hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, allyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, dodecyl methacrylate, octyl methacrylate, pentyl methacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, propylene glycol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate, etc.
In this invention, when there are taken the number of unsaturated groups in the unsaturated polyester (I) as (a), that of unsaturated groups in the styrene monomer and/or a derivative thereof (II) as (b), and that of unsaturated groups in the polymerizable unsaturated compound (III) as (c), the unsaturated polyester is dissolved in the styrene monomer and/or a derivative thereof and the polymerizable unsaturated compound (III) in the range:
(b)/{(c)}=1/10-10/1.
When the polymerizable unsaturated compound is (i), a range:
(b)/{(a)+8c)}=5/10-10/1
is preferred.
When (b)/{(a)+(c)} exceds 10/1, luminant spots are increased, resulting in an increase of fraction defective. When (b)/{(a)+(c)} is less than 5/10, the viscosity is increased, resulting in a lowering of defoaming properties and great prolongation of curing, therefore the workability is greatly lowered, so that there is strengthened the tendency that surface defects due thereto such as foams, resin leakage, casting shortage and the like are caused.
In the case of the polymerizable unsaturated compound being (ii), when the ratio (b)/{(a)+(c)} is more than 10/1, the mixing ratio of curing agent differs from a predetermined condition in curing the unsaturated polyester resin composition for the treatment, and cure distortion is easily caused by the unevenness of the temperature of curing oven at the time of curing and by the difference between the temperature of the unsaturated polyester resin composition containing the curing agent and the temperature of the front glass set of a cathode-ray tube into which said composition is to be casted. Therefore, a strped pattern or luminant spots appear on the screen, so that the commercial value is lost.
On the other hand, when the ratio (b)/{(a)+(c)} is less than 1/10, the viscosity-lowering effect of the styrene monomer and/or a derivative thereof which have a low viscosity is lost, therefore the workability is lowered. For example, casting of the resin composition becomes very difficult, and defoaming at the time of mixing or casting a curing agent is deteriorated. The ratio (b)/{(a)+(c)} is more preferably in the range of 1/2-5/1. In the case of above (ii), although the unsaturated polyester (I) may be dissolved in a mixture of the styrene monomer and/or a derivative thereof (II) and the monester and/or diester of an unsaturated dibasic acid, it is also possible to dissolve the unsaturated polyester in the styrene monomer and/or a derivative thereof previously and add thereto the monester and/or diester of an unsaturated dibasic acid. Further, it is also possible to dissolve the unsaturated polyester in the monoester and/or diester of an unsaturated dibasic acid and add thereto styrene and/or a derivative thereof.
In the case of above (iii), although the unsaturated polyester (I) maya be dissolved in a mixture of styrene and/or a derivative thereof (II) and acrylic acid, methacrylic acid or a derivative thereof, it is also possible to dissolve the unsaturated polyester in styrene and/or a derivative thereof prevously and add thereto acrylic acid, methacrylic acid or a derivative thereof. Further, it is also possible to dissolve the unsaturated polyester in acrylic acid, methacrylic acid or a derivative thereof and add thereto styrene and/or a derivative thereof.
The unsaturated polyester resin composition thus prepared may, if necessary, contain polymerization inhibitors such as hydroquinone, pyrocatechol, 2,6-di-tert-butylparacresol, p-benzoquinone, di-t-butylcatechol, hydroquinone monomethyl ether, t-butylcatecol, mono-t-butylhydroquinone and the like. Although the amount of the polymerization inhibitor added is not critical, it is preferably 0 to 0.03 part by weight per 100 parts by weight of the unsaturated polyester composition.
Organic peroxides used for curing the resin composition of this invention include, for example, methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene hydroperoxide, dicumyl peroxide, acetylacetone peroxide, benzoyl peroxide, lauroyl peroxide, cumene peroxide, etc. These compounds may be used alone or in combination. Although the amount of the organic peroxide added is not critical, it is preferably 0.1 to 2 parts by weight per 100 parts by weight of the unsaturated polyester resin composition. Further, if necessary, a cure accelerator can be used.
The resin composition for treating cathode-ray tubes is obtained by adding 0.5 to 10 parts by weight of maleic anhydride to 100 parts by weight of the unsaturated polyester resin composition described above.
When the amount of maleic anhydride is less than 0.5 part by weight, improvement of the adhesion to glass, namely, the effect of the addition of maleic anhydride cannot be attained. When it exceeds 10 parts by weight, the cured product becomes too hard, so that recovery of the cathode-ray tube becomes impossible, and a part of the maleic anhydride crystallizes, resulting in appearance of luminant spots.
Maleic anhydride may be previously heated to about 54° to about 60° C. to be liquefied and then added to the unsaturated polyester resin composition, or alternatively maleic anhydride may be added to the unsaturated polyester resin composition and then heated to about 54° to about 60° C. to be dissolved.
The thus prepared resin composition for treating cathode-ray tubes is, if necessary, incorporated with a polymerization inhibitor such as hydroquinone, pyrocatechol, 2,6-di-tert-butylparacresol or the like, after which it can be cured by using an organic peroxide catalyst such as methyl ethyl ketone peroxide, benzoyl peroxide, cumene hydroperoxide, lauroyl peroxide or the like.
These organic peroxide catalysts can be used in combination with cure accelerators, for example, metallic soaps such as cobalt naphthenate, cobalt octenoate and the like; quaternary ammonium salts such as dimethylbenzylammonium chloride and the like; β-diketones such as acetylacetone and the like; amines such as dimethylaniline, N-ethyl-metatoluidine, triethanolamine and the like; etc.
The resin composition of this invention can also be light-cured by using as a photopolymerization initiator, for example, diphenyl disulfide, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin sec-butyl ether, benzoin-2-pentyl ether, benzoin cyclohexyl ether, dimethylbenzyl ketal or the like.
The above-mentioned organic peroxides and these photopolymerization initiators may be simultaneously used.
Further, the resin composition may, if necessary, contain dyes, plasticizers, ultraviolet ray absorbing agents, and the like.
The resin composition for treating cathode-ray tubes is casted into the gap between the front glass and face-plate portion of a cathode-ray tube such as a Braun tube of television, a display tube for computer or the like and cured.
This invention is illustrated by way of the following Examples, in which all parts are by weight unless otherwise specified.
EXAMPLES 1 TO 9
Into a 3-liter four-necked flask equipped with a stirring rod, condenser, nitrogen gas inlet tube and thermometer were charged the following ingredients:
______________________________________diethylene glycol 1,166 partsadipic acid 584 partsphthalic anhydride 740 partsfumaric acid 116 parts.______________________________________
While introducing nitrogen gas slowly into the flask, the temperature was raised to 150° C. over a period of 1.5 hours by using a mantle heater. Further, the temperature was raised to 200° C. over a period of 4 hours and maintained at this temperature. An unsaturated polyester (A) having an acid value of 34 was obtained in about 10 hours. Further, the temperature was lowered to 100° C., and 1 part of hydroquinone was added as a polymerization inhibitor, after which the unsaturate polyester (A) incorporated with hydroquinone was poured into a stainless-steel vat and allowed to stand to be cooled to room temperature. The unsaturated polyester (A) thus obtained had a molecular weight of 2440 per unsaturated group.
This unsaturated polyester (A) was dissolved in a mixed solution of styrene and a polymerizable unsaturated compound according to the recipes shown in Table 1 to obtain unsaturated polyester resin compositions.
Maleic anhydride which was solid at ordinary temperatures was added to the unsaturated polyester resin compositions according to the recipes shown in Table 1, and the resulting mixtures were heated to 57° C. to dissolve maleic anhydride, whereby homogeneous unsaturated polyester resin compositions for treating cathode-ray tubes were obtained.
To each of the resin compositions thus obtained were added 0.025 part of cobalt octenoate (manufactured by Dainippon Ink and Chemicals, Inc., metal content 6% by weight) and 1 part of methyl ethyl ketone peroxide (manufactured by Nippon Oils and Fats Co., Ltd.).
On the other hand, on a 3 mm (thickness)×250 mm×250 mm, transparent, flat glass plate was placed, as a spacer, a silicone plate prepared by cutting the inner part in a size of 240 mm×240 mm out of a 3 mm (thickness)×250 mm×250 mm silicone plate with a razor so as to leave the peripheral part, and then providing a slit inlet in one place in the remaining peripheral part. A 3 mm (thickness)×250 mm×250 mm, transparent, flat glass plate was placed on the spacer, and the two glass plates were fastened to each other with clamps to obtain a casting mold. The unsaturated polyester resin composition described above was poured through the slit inlet of the spacer in the casting mold.
Thereafter, the casting mold was allowed to stand in an electric oven at 80° C. for 90 minutes to cure the resin, whereby an unsaturated polyester resin casted plate was obtained.
Characteristics of the casted plates thus obtained are shown in Table 1.
As Comparative Examples 1 and 2, compositions were prepared according to the recipes shown in Table 1 by using the aforesaid unsaturated polyester (A) in Examples 1 to 9, and characteristics of casted plates were evaluated in the same manner as described above.
In the case of Examples 1 to 9, no cure distortion occurred at the time of curing, and neither striped pattern nor luminant spot was observed. However, in the case of Comparative Examples 1 and 2, neither striped pattern nor luminant spot was observed, but when the casted plates were allowed to stand in an electric oven at 150° C. for 96 hours, peeling-off occurred: thus Comparative Examples 1 and 2 were inferior to Examples 1 to 9 in adhesive strength.
TABLE 1__________________________________________________________________________ Comparative Example Example 1 2 3 4 5 6 7 8 9 1 2__________________________________________________________________________ (a) Unsaturated 100 100 100 100 100 100 100 100 100 100 100 polyester (A) (0.04) (0.04) (0.04) (0.04) (0.04) (0.04) (0.04) (0.04) (0.04) (0.04) (0.04) (b) Styrene 25 25 30 25 5 23 24 24 18 25 25 (0.24) (0.24) (0.29) (0.24) (0.05) (0.22) (0.23) (0.23) (0.17) (0.24) (0.24) Dibutyl fumarate 15 7.5 -- -- -- -- -- -- -- 15 -- (0.06) (0.03) (0.06)Recipe Methyl -- -- 5 15 30 -- -- -- -- -- 5(parts) methacrylate (0.05) (0.15) (0.05) (0.05) (c) Acrylonitrile -- -- -- -- -- 7 -- -- 10 -- -- (0.13) (0.19) Itaconic acid -- -- -- -- -- -- 5 -- -- -- -- (0.04) Citraconic -- -- -- -- -- -- -- 5 -- -- -- anhydride (0.05)Maleic anhydride 3 3 3 3 3 3 3 3 3 -- --(b)/{(a) + (c)} 2.4 3.4 3.2 1.3 0.15 1.2 2.6 2.3 0.7 2.4 3.2Cure Striped pattern None None None None None None None None None None Nonedistortion Luminant spot None None None None None None None None None None NonePeeling-off Initial stage None None None None None None None None None None None After 150° C./96 hrs None None None None None None None None None About About 10% 7%Adhesive strength (kg/cm.sup.2) 24 28 25 22 21 26 24 29 27 13 16__________________________________________________________________________ Note: The figures in the parentheses are the number of unsaturated groups.
In Table 1 (the same applied to Table 2), cure distortion was visually observed: the existence of a striped pattern was invertigated, and the number of luminant spots was reckoned. Peeling-off was also visually observed, and whether it occurred or not and the area which it covered are shown.
The adhesive strength is shown in terms of a value obtained by placing two 10 mm (thickness)×40 mm×'mm glass plates one upon another in imperfect accord so as to adjust the contacted area to 20 mm×°mm, adhering them to each other with the unsaturated polyester resin composition (curing conditions: methyl ethyl ketone peroxide 1% by weight, curing at 80° C. for 5 hours), holding the resulting assembly between spacers on both sides, applying a compression load thereto from above and below, and dividing a shearing force at which the adhesion surface was fractured, by the adhered area.
EXAMPLES 10, 11 AND 12
Into a 3-liter four-necked flask equipped with the same devices as in Example 1 were charged the following ingredients:
______________________________________dipropylene glycol 1,474 partsadipic acid 1,241 partsmaleic anhydride 147 parts______________________________________
While introducing nitrogen gas slowly into the flask, the temperature was raised to 150° C. over a period of 1 hour by using a mantle heater. Further, the temperature was raised to 200° C. over a period of 4 hours and maintained at this temperature. After about 12 hours, an unsaturated polyester (B) having an acid value of 25 was obtained.
Further, the temperature was lowered to 100° C., and 1 part of hydroquinone was added as a polymerization inhibitor, after which the unsaturated polyester (B) incorporated with hydroquinone was poured into a stainless-steel vat and allowed to stand to be cooled to room temperature.
The unsaturated polyester (B) thus obtained had a molecular weight of 1710 per unsaturated group.
This unsaturated polyester was dissolved in a mixed solution of styrene and diethyl fumarate according to the recipes shown in Table 2, after which maleic anhydride which had previously been liquefied by heating was added to the resulting solutions to obtain unsaturated polyester resin compositions.
Characteristics of casted plates obtained by curing each of the unsaturated polyester resin compositions in the same manner as in Examples 1 to 9 are shown in Table 2.
In Examples 10, 11 and 12, no cure distortion was observed.
TABLE 2__________________________________________________________________________ Example 10 Example 11 Example 12__________________________________________________________________________ Unsaturated 100 parts (0.06) 100 parts (0.06) 100 parts (0.06) polyester B (a)Recipe Styrene (b) 25 parts (0.24) 20 parts (0.19) 15 parts (0.14) Diethyl fumarate (c) 5 parts (0.03) 10 parts (0.07) 15 parts (0.10) (b)/{(a) + (c)} 2.7 1.5 0.9 Maleic anhydride 5 parts 5 parts 5 partsCure Striped pattern None None Nonedistortion Luminant spot None None NonePeeling-off Initial stage None None None After 150° C./96 hrs None None NoneAdhesive strength (kg/cm.sup.2) 30 21 14__________________________________________________________________________ Note: The figures in the parentheses are the number of unsaturated groups.
EXAMPLE 13
Into a 3-liter four-necked flask equipped with a stirring rod, condenser, nitrogen gas inlet tube and thermometer were charged the following ingredients:
______________________________________maleic anhydride 147 parts3,6-endomethylene-1,2,3,6- 1,394 partstetrahydrophthalic anhydride(HIMIC anhydride, a trade name,mfd. by Hitachi Chemical Company,Ltd.)diethylene glycol 1,166 parts______________________________________
While introducing nitrogen gas slowly into the flask, the temperature was raised to 150° C. over a period of 1.5 hours by using a mantle heater. Further, the temperature was raised to 200° C. over a period of 4 hours and maintained at this temperature. After about 10 hours, an unsaturated polyester (C) having an acid value of 24 was obtained. The unsaturated polyester (C) obtained had a molecular weight of 1680 per unsaturated group.
In 100 parts of the unsaturated polyester (C) were dissolved 25 parts of styrene, 8 parts of diethyl fumarate and 0.01 part of hydroquinone as a polymerization inhibitor. Further, 0.05 part of cobalt naphthenate (manufactured by Dainippon Ink and Chemicals, Inc., metal content 6% by weight) and 6 parts of liquid maleic anhydride heated to 60° C. were dissolved therein to obtain a resin composition for treating cathode-ray tubes which had a viscosity of 3.9 poises (25° C., Gardner-Holdt bubble viscometer).
On a 3 mm (thickness)×250 mm×250 mm transparent glass plate was placed, as a spacer, a silicone plate prepared by cutting the inner part in a size of 240 mm×240 mm out of a 3 mm (thickness)×250 mm×250 mm silicone plate with a razor so as to leave the peripheral part, and then providing a slit inlet in one place in the remaining peripheral part. A 3 mm (thickness)×250 mm×250 mm, transparent, flat glass plate was placed on the spacer, and the two glass plates were fastened to each other with clamps to produce a casting mold. An unsaturated polyester resin composition prepared by adding 1 part of methyl ethyl ketone peroxide (a mixture of 55% by weight of methyl ethyl ketone peroxide and 45% by weight of dimethyl phthalate, manufactured by Nippon Oils and Fats Co., Ltd.) to 100 parts of the unsaturated polyester resin composition was poured through the slit inlet of the spacer in the casting mold. Thereafter, the casting mold was allowed to stand in an electric oven at 80° C. for 60 minutes to cure the resin, whereby an unsaturated polyester resin casted plate was obtained.
After cooling, whether a striped pattern or luminant spots due to cure distortion existed or not was visually judged. Peeling-off was also visually observed, and whether it occurred or not and the area which it covered are shown. The casting mold was then allowed to stand in an electric oven at 150° C. for 96 hours, and after cooling, peeling-off was observed.
The adhesive strength is shown in terms of a value obtained by placing two 10 mm (thickness)×40 mm×40 mm glass plates one upon another in imperfect accord so as to adjust the contacted area to 20 mm×20 mm, adhering them to each other with the unsaturated polyester resin composition (curing conditions: methyl ethyl ketone peroxide 1% by weight, curing at 80° C. for 5 hours), holding the resulting assembly between spacers on both sides, applying a compression load thereto from above and below, and dividing a shearing force at which the adhesion surface was fractured, by the adhered area.
The recipe and characteristics such as cure distortion and the like are shown in Table 3.
EXAMPLE 14
In 100 parts of the unsaturated polyester resin (C) obtained in Example 13 were dissolved 25 parts of styrene, 10 parts of monomethyl maleate and 0.01 part of hydroquinone. Further, 0.05 part of cobalt naphthenate (metal content 6% by weight) and 5 parts of liquid maleic anhydride heated to 60° C. were dissolved therein to obtain an unsaturated polyester resin composition having a viscosity of 2.3 poises (25° C., Gardner-Holdt bubble viscometer). The resin composition was cured in the same manner as in Example 13. The results are shown in Table 3.
EXAMPLE 15
Into the same apparatus as in Example 13 were charged the following ingredients:
______________________________________fumaric acid 116 parts3,6-endomethylene-1,2,3,6- 1,274 partstetrahydrophthalic acidadipic acid 29 partsdipropylene glycol 1,541 parts.______________________________________
They were reacted by the same synthesis process as in Example 13, and the temperature was maintained at 200° C. After about 12 hours, an unsaturated polyester (D) having an acid value of 20 was obtained. The unsaturated polyester (D) obtained had a molecular weight of 2860 per unsaturated group.
In 100 parts of the unsaturated polyester (D) were dissolved 25 parts of styrene, 8 parts of diethyl fumarate and 0.025 part of t-butylcatechol. Further, 0.05 part of cobalt octenoate (manufactured by Dainippon Ink and Chemicals, Inc., metal content 6% by weight) and 3 parts of liquid maleic anhydride heated to 60° C. were dissolved therein to obtain a resin composition for treating cathode-ray tubes which had a viscosity of 3.3 poises (25° C., Gardner-Holdt bubble viscometer).
This resin composition was cured and then tested for characteristics both in the same manner as in Example 13. The recipe and characteristics such as cure distortion and the like are shown in Table 3.
COMPARATIVE EXAMPLES 3 TO 5
Compositions were prepared in the same manner as with the unsaturated polyester resin compositions obtained in Examples 13 to 15 respectively, except that no maleic anhydride was added. The compositions thus prepared were cured and then tested for characteristics both in the same manner as in Example 13. The recipes and characteristics such as cure distortion are shown in Table 3.
COMPARATIVE EXAMPLE 6
Into the same apparatus as in Example 6 were charged the following ingredients:
______________________________________maleic anhydride 588 parts3,6-endomethylene-1,2,3,6- 656 partstetrahydrophthalic anhydride(mfd. by Hitachi ChemicalCompany, Ltd.)diethylene glycol 1,166 parts.______________________________________
They were reacted by the same synthesis process as in Example 6, and the temperature was maintained at 200° C. After about 8 hours, an unsaturated polyester (E) having an acid value of 29 was obtained. The unsaturated polyester (E) obtained had a molecular weight of 370 per unsaturated group.
In 100 parts of the unsaturated polyester (E) were dissolved 25 parts of styrene, 8 parts of diethyl fumarate and 0.01 part of hydroquinone. Further, 0.05 part of cobalt naphthenate (metal content 6% by weight) and 6 parts of liquid maleic anhydride heated to 60° C. were dissolved therein to obtain an unsaturated polyester resin composition having a viscosity of 8.3 poises (25° C., Gardner-Holdt bubble viscometer), which was then cured in the same manner as in Example 13. Its characteristics were evaluated. The recipe and characteristics such as cure distortion are shown in Table 3.
TABLE 3______________________________________ Example Example 13 14 (C) (C)______________________________________ Unsaturated 100 parts 100 parts polyester Styrene monomer Styrene 25 parts 25 parts and/or a derivative thereof Monoester and/or Diethyl 8 parts -- diester of fumarate unsaturatedRecipe dibasic acid Monomethyl -- 10 parts maleate(a) 0.06 0.06(b) 0.24 0.24(c) 0.05 0.08(b)/{(a) + (c)} 2.2 1.7 Maleic anhydride 6 parts 5 partsCure Striped pattern None Nonedistortion Luminant spot None NonePeeling- Initial stage None Noneoff After 150° C./96 hrs None NoneAdhesive strength (kg/cm.sup.2) 31 29______________________________________ Com- Com-Example Comparative parative Comparative parative15 Example 3 Example 4 Example 5 Example 6(D) (C) (C) (D) (E)______________________________________100 parts 100 parts 100 parts 100 parts 100 parts25 parts 25 parts 25 parts 25 parts 25 parts8 parts 8 parts -- 8 parts 8 parts-- -- 10 parts -- --0.03 0.06 0.06 0.03 0.270.24 0.24 0.24 0.24 0.240.05 0.05 0.08 0.05 0.053 2.2 1.7 3 0.83 parts -- -- -- 6 partsNone None None None NoneNone None None None NoneNone None None None NoneNone About 5% About 5% About 5% About 20%27 14 16 15 93______________________________________
The resin composition for treating cathode-ray tubes of this invention is characterized in that it can greatly reduce cure distortion which occurs in conventional resin compositions, that it forms no crack, and that it is so excellent in adhesiveness to glass plates that it causes no peeling-off. | A resin composition obtained by adding maleic anhydride to an unsaturated polyester resin composition comprising (I) an unsaturated polyester, (II) a styrene monomer, and (III) at least one polymerizable unsaturated compound, in limited amounts is low in viscosity, excellent in transparency and adhesiveness, able to prevent the generation of surface defects, and thus suitable for treating cathode-ray tubes. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to appliances used for floor cleaning and the like. More specifically, the present invention relates to a means for adjusting the disposition of a vacuum cleaner carriage relative to a floor surface.
Vacuum cleaners of the floor cleaning or upright type generally include a chassis having a nozzle on a lower surface of a front end thereof through which air is sucked by an air moving motor-blower unit. A rotary brush is mounted adjacent the nozzle for contacting the floor surface to agitate and loosen dirt so that it may be sucked free of the surface. Wheels or other supports are rotatably mounted at the front and rear of the chassis for supporting the cleaner in a rolling manner on the floor. These vacuum cleaners are called upon to clean many different kinds of modern floor coverings varying in pile thickness from the short outdoor or patio-type carpeting to the long deep shag-type.
In order to clean these various floor surfaces effectively, it is known to vary the vacuum cleaner's nozzle height in order to locate the nozzle at a proper level above the surface to provide the required suction for the particular type of floor covering or surface being cleaned and to position the brush at the proper height. While many types of nozzle height adjusting mechanisms are known to the art, the known mechanisms are relatively complex and include a large number of parts because many nozzle heights are necessary to handle the different kinds of modern floor coverings available. The inherent multiplicity of such parts has made it more expensive to manufacture and assemble an upright vacuum cleaner.
One of the most common models of vacuum cleaners has a somewhat T-shaped housing which is supported on a widely spaced set of front wheels and a narrowly spaced set of rear wheels. The rear wheels are mounted on a carrier fork that extends rearward from a transverse horizontal pivot shaft. A height adjustment for this type of vacuum cleaner can be obtained through the use of a screw which is provided through a hole in the rear end of the rear housing and engages a cross brace on the rear wheel carrier fork. By manually turning the screw in one direction, the rear of the unit is lowered causing the floor cleaning nozzle to pivot about the front wheels in a downward direction. Turning the screw in the opposite direction allows the pivot shaft spring to raise the rear wheels and cause the floor cleaning nozzle to rise. When the manual turning of the screw produces the desired nozzle position, the rotation of the screw can be stopped.
Unfortunately, this type of height adjustment mechanism is time consuming to use and requires that the operator kneel down each time an adjustment needs to be made to the vacuum cleaner's height. Also, constant use of such a height adjustment mechanism, such as when the vacuum cleaner is used in an institutional setting, for example in a hospital, hotel or office building, will lead to the breakage of this conventional height adjustment mechanism.
Another problem with this known type of vacuum cleaner is that the rear wheel carrier fork sometimes jams against the underside of the vacuum cleaner housing beyond the maximum height adjustment position. This occurs most frequently when the vacuum cleaner is being pulled backwards and the rear wheels strike a raised section of the floor surface, such as the edge of a carpet. Although a pivot spring is provided to bias the carrier fork and prevent such doubling under, the spring often weakens with age or breaks thereby allowing this type of action to occur.
Accordingly, it has been considered desirable to develop a new and improved vacuum cleaner height adjusting mechanism which is mechanically simple, compact, durable in nature and which overcomes the foregoing difficulties and others while providing better and more advantageous results.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, a foot operated nozzle height adjusting mechanism is provided for a vacuum cleaner of the type characterized by a housing having a front cleaning nozzle that is pivotable about a pair of front wheels through the change in height of a pair of rear wheels that are secured in a wheel fork that is pivotally mounted on the housing.
More particularly in accordance with the invention, the height adjusting mechanism comprises a first pedal secured to the wheel fork and a second pedal pivotally secured to the housing and including an adjustment lever extending in a direction substantially normal to the wheel fork. The adjustment lever includes a plurality of spaced teeth. A locking plate is secured to the wheel fork wherein the spaced teeth of the adjustment lever are adapted to selectively engage the locking plate. A means for biasing the adjustment lever teeth against the locking plate is also provided.
In accordance with another aspect of the present invention, a vacuum cleaner is provided.
More particularly in accordance with this aspect of the invention, the vacuum cleaner comprises a carriage including front and rear support means rotatably carried by the carriage for movably supporting the carriage on a subjacent surface. A floor cleaning nozzle is generally horizontally disposed adjacent the front support means of the vacuum cleaner. A first pedal, secured to the rear support means, is provided for adjusting the height of the nozzle in relation to the subjacent surface. A second pedal which is rotatably secured to the carriage is provided for holding a height selected by the first pedal. The second pedal comprises a foot contact portion, a pivot portion at which the second pedal is secured to the carriage and a lever portion provided with a plurality of spaced teeth. A means for resiliently biasing the second pedal in a first direction in relation to the carriage is also provided.
In accordance with still another aspect of the present invention, a nozzle height adjusting mechanism is provided for a vacuum cleaner having a carriage with a front floor cleaning nozzle that is pivotable about a pair of front wheels through the change in height of a rear end of the carriage.
More particularly in accordance with this aspect of the invention, the mechanism comprises a wheel fork for holding a pair of rear wheels mounted on an axle. The rear wheels rotatably support the rear end of the carriage. The fork comprises a front end which is pivotally secured to the carriage, a locking plate portion, a center portion to which the axle can be secured and a pedal portion. A second pedal is pivotally secured to the housing and includes an adjustment lever extending in a direction substantially normal to the wheel fork. The adjustment lever includes a plurality of spaced teeth wherein the spaced teeth of the adjustment lever are adapted to selectively engage the wheel fork locking plate portion. Also provided is a means for biasing the adjustment lever teeth against the locking plate portion.
One advantage of the present invention is the provision of a new and improved appliance height adjustment mechanism.
Another advantage of the present invention is the provision of a vacuum cleaner nozzle height adjustment mechanism that is simple and economical in construction while yet providing a rugged and durable device.
Still another advantage of the present invention is the provision of a vacuum cleaner nozzle height adjustment mechanism which can be readily adjusted for different pile heights without the operator having to kneel down to make the adjustments.
Yet another advantage of the present invention is the provision of a vacuum cleaner nozzle height adjustment mechanism which is controlled through a pair of spaced pedals.
Still yet another advantage of the present invention is a vacuum cleaner nozzle height adjustment mechanism in which a first pedal is utilized to decrease the nozzle height of the vacuum cleaner in a stepped manner and a second pedal is utilized to return the vacuum cleaner's nozzle height to a maximum position.
A further advantage of the present invention is the provision of a vacuum cleaner nozzle height adjustment mechanism which includes a resilient biasing means for holding the nozzle height at a set position.
Still other benefits and advantages of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed specification.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof, and wherein:
FIG. 1 is a perspective view of a rear end of a vacuum cleaner having a height adjustment mechanism according to the preferred embodiment of the present invention;
FIG. 2 is an enlarged side elevational view partially in cross-section through the nozzle height adjustment mechanism of FIG. 1; and,
FIG. 3 is a top plan view of a wheel fork and axle assembly of the nozzle height adjusting mechanism of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, wherein the showings are for purposes of illustrating a preferred embodiment of the invention only and not for purposes of limiting same, FIG. 1 shows the preferred embodiment of the subject new appliance height adjusting mechanism A. While the mechanism is primarily designed for and will hereinafter be described for use with an upright vacuum cleaner B, it should be appreciated that the overall inventive concept involved could be adapted for use in many other appliance environments as well.
A housing or carriage 10 of the vacuum cleaner B includes a wide front floor cleaning nozzle 12 directed downward for suction cleaning of carpets and floors. The nozzle passes dirt laden air upwardly into a central duct 14 and then into the center of a centrifugal fan (not visible). The dirt laden air is swirled at high velocity inside a centrifugal fan housing (not visible) where it is caused to exit through a side mounted exit duct (not visible) into a dirt catching bag 20. The nozzle 12 is pivotally supported on a pair of widely spaced front wheels 22. The electric motor which powers the fan is housed in a motor housing 24 that extends rearwardly from the front wheels 22. A handle (not visible) is attached to the housing 10 in order to allow a desired movement of the vacuum cleaner A.
With reference now to FIG. 2, rear support is provided for the vacuum cleaner by a wheel fork 30 which includes a pivot section 32 having a through bore 34 extending therethrough. As shown in FIG. 3, the pivot section includes a pair of spaced arms 35. A fastener 36 secures the pivot section 32 to a flange 38 extending rearwardly from a lower periphery of the housing 10. Provided adjacent the pivot section 32 of the wheel fork 30 is a lock plate 40. As best shown in FIG. 3, the lock plate includes a longitudinally extending slot 42 which is substantially centrally disposed along the longitudinal axis of the wheel fork 30. At the rear of the slot is an engagement surface 43.
Provided adjacent the lock plate 40 is an axle section 44 of the wheel fork 30. The axle section includes a pair of spaced arms 46 each of which has an aperture 48 extending therethrough in a direction normal to the longitudinal axis of the wheel fork 30. The apertures allow an axle shaft 50 to be staked therethrough. A first wheel 52 is rotatably secured at one end of the axle shaft 50 while a second wheel 54 is rotatably secured at the other end of the axle shaft. In this way, the rear support for the vacuum cleaner is provided by the pair of spaced wheels 52 and 54. As shown in FIG. 1, these wheels are narrowly spaced in comparison to the front wheels 22. Extending rearwardly from the axle section 44 of the wheel fork 30 is a first pedal section 56.
Provided on a rear end of the housing 10 is a protrusion 60 through which extends a vertically running bore 62. An elongated member 70 extends through the bore 62 in a vertically oriented direction. In other words, the member 70 is substantially normal to the approximately horizontal direction of the wheel fork 30 with which the member 70 cooperates.
The member 70 includes at its lower end a lever portion 74 which has a rear face 76 that is provided with a plurality of spaced teeth 78. Preferably, five such teeth are provided allowing for five height settings for the vacuum cleaner nozzle. Located adjacent a lower most one of the teeth 78 is a flange 80 which extends back in the same plane as the teeth 78 in order to create a large slot 81. Provided for the lever portion 74 is a first stop surface 82 which defines a lower limit of the movement of the pedal 70 and a second stop surface 84 which defines an upper limit of the movement of the pedal 70.
Located on a front face 86 of the lever portion 74 is a tooth 88 which extends away from the front face 86. Located adjacent the tooth 88 is a pivot section 90 of the pedal 70. The pivot section includes an aperture 92 through which extends a fastener 94 that rotatably secures the pedal 70 in the bore 62 of the rear protrusion 60 of the housing 10.
Located above the pivot section 90 of the member 70 is a second pedal section 96. It is noted that while the lever portion 74 and pivot section 90 of the pedal member 70 extend vertically, the second pedal section 96 extends horizontally through an appropriate bend in the metal from which the pedal member 70 is preferably made.
Therefore, the second pedal section 96 lies in a plane parallel to the plane in which the first pedal section 56 is located, as best shown in FIG. 2. The two pedal members are not only spaced vertically from each other, but are also spaced horizontally such that the first pedal section is located somewhat to the rear of the second pedal section 96. In this way, unrestricted access is provided to the operator's foot for each of the pedal sections.
Resiliently biasing the member 70 in a counterclockwise direction around the rear protrusion 60 is a biasing means which can be a compression spring 100. The spring includes a front arm 102 which extends into a suitably formed slot 104 provided in the housing or carriage 10 in order to secure the spring in place. A rear end 106 of the spring extends over the tooth 88 of the pedal member 70 such that the last few coils of the spring 100 are held in suitable slots 110, 112 provided on either side of the tooth 88 in the pedal member 70.
The operation of the height adjustment mechanism is as follows. Let us assume that the vacuum cleaner nozzle 12 is at its highest position in relation to the subjacent floor surface. If it is desired to move the nozzle closer to the surface, the operator need merely to step on the first or height adjustment pedal section 56. This will move the point of engagement between the lock plate 40 and a tooth 88 of the pedal member 70 to the next lower tooth. The next lower tooth 88 will catch on the lock plate engagement surface 43 and hold there due to the resilient bias provided by the spring 100. At the next lower position, the wheel fork 30 now stands at a somewhat greater angle in relation to the longitudinal axis of the housing or carriage 10. This then will tilt the carriage forwardly about the two front wheels 22 thereby lowering the nozzle 12 in relation to the floor surface. This action can, if desired, be continued until the lowest tooth 88 of the lever portion 74 is in contact with the lock plate 40.
An upwardly angled finger 118 is provided adjacent the first stop surface 82 so as to somewhat enclose the slot 81 on the member 70. The finger 118 cooperates with a back surface of the lock plate 40 in order to prevent the wheel fork 30 from being inadvertently moved or rotated without a positive pivoting of the member 70 by the operator stepping on the pedal section 96. Such inadvertent movement may take place when the vacuum cleaner is jogged while it is being rolled between floor surfaces of different relative heights, such as from tile to carpeting or vice versa. The finger 118 also prevents the wheel fork 70 from being rotated any further counterclockwise, should the operator step on the pedal 56.
When it is desired to again select the highest setting of the vacuum cleaner's nozzle, one need merely press the release pedal or second pedal section 96. As the release pedal 96 is contacted by the operator's foot, the pedal member is rotated around the fastener 94 and pressure is exerted against the spring 100 to disengage the respective tooth 78 from the lock plate 40. Thereby the wheel fork 30 is allowed to move upwardly in relation to the rear protrusion 60 of the housing 10 to the uppermost limit provided by the second stop surface 84 which is formed by the highest tooth on the rear face 76 of the lever portion 74. Such a pivoting motion of the wheel fork 30 is caused to some extent by the weight of the carriage, and the rest of the vacuum cleaner, due to the force of gravity. Aiding the pivoting motion is a spring 120, best shown in FIG. 3, which has a first end 122 extending beneath the lock plate 40 and a central portion 124 coiled around the fastener 36. A second end 126 of the spring extends below a lower edge 128 of the motor housing 24 as shown in FIG. 2. The spring 120 exerts a counterclockwise bias on the wheel fork 30 to urge the wheel fork toward the protrusion 60.
It should be clear that a simple, inexpensive and sturdy nozzle height adjusting mechanism comprising a minimum number of parts has been disclosed in this application. While the invention has been described with reference to a preferred embodiment, obviously, modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. | A foot operated nozzle height adjusting mechanism for a vacuum cleaner of the type characterized by a housing having a front cleaning nozzle that is pivotable about a pair of front wheels through the change in height of a pair of rear wheels that are secured in a wheel fork pivotally mounted on the housing includes first and second pedals. The first pedal is secured to the wheel fork. The second pedal is provided on a member that is pivotally secured to the housing and includes an adjustment lever extending in a direction substantially normal to the wheel fork. The adjustment lever includes a plurality of spaced teeth. A locking plate is secured to the wheel fork and the spaced teeth of the adjustment lever are adapted to selectively engage the locking plate. A biasing element urges the adjustment lever teeth against the locking plate. | 0 |
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