KR100776851B1 - Electrical device comprising carbon fiber electrical contacts formed of composite carbon fiber material - Google Patents

Abstract

The present invention relates to a non-metallic electrical contact or wiper composed of carbon fiber composite material through which electrical signals can be transmitted. Carbon fibers may be fusing together or electrically conductively bonded together and used to form the main signal conductor. A mat formed of nonwoven carbon fibers is placed on each flat surface of the bonded carbon fibers, and then a layer of thermoplastic resin is applied over each nonwoven mat. Nonwoven carbon fiber mats also conduct electrical signals and increase the mechanical stability of electrical contacts or wipers formed from carbon fiber composite materials.

Description

ELECTRICAL DEVICE COMPRISING CARBON FIBER ELECTRICAL CONTACTS FORMED OF COMPOSITE CARBON FIBER MATERIAL}

1A-1D are side views illustrating each embodiment of an electrical contact in accordance with the present invention.

2A-2C are front and respective enlarged views, respectively, illustrating an embodiment of an electrical contact corresponding to FIGS. 1A-1C.

3 is two views showing carbon fiber contacts formed as a matrix of carbon fiber layers.

4 is two views showing carbon fiber contacts formed as a matrix of carbon fiber layers.

5 is two views showing electrical contacts formed solely of carbon fiber in accordance with an embodiment of the invention.

6 is two views showing electrical contacts formed solely of carbon fiber according to another embodiment of the present invention.

FIG. 7 is two diagrams illustrating carbon fiber electrical contacts attached to an electrically conductive beam in accordance with an embodiment of the invention.

8 is two diagrams illustrating electrical contacts in which carbon fibers are mechanically captured and chemically fused in accordance with an embodiment of the present invention.

9 is two views showing electrical contacts in which carbon fibers are mechanically captured and chemically fused in accordance with an embodiment of the invention.

10 is two diagrams illustrating electrical contacts in which carbon fibers are mechanically captured and chemically fused in accordance with an embodiment of the present invention.

11 is two diagrams illustrating electrical contacts employing multiple layers on a carrier in accordance with an embodiment of the invention.

12 is two views showing electrical contacts formed as one carbon fiber element.

13 is an exploded view showing carbon fibers disposed in parallel with two carbon fiber nonwoven mats.

14 is a cross-sectional view showing the various layers that make up an embodiment of a carbon fiber composite material according to the present invention.

FIELD OF THE INVENTION The present invention relates generally to electrical contacts or electrical contact assemblies typically used in electromechanical devices, and more particularly to carbon fibers as elements forming electrical contact with other elements of the electromechanical device. And a contact or contact assembly formed from a composite material using a nonwoven carbon fiber mat.

Variable resistance devices use elements that change voltage or current to provide an electrical signal that indicates a relationship with the physical location of a contact or wiper on a resistive or conductive element. Because these variable resistive devices are used in a dynamic state, they cannot be fixed or restricted in movement and must be freely disposed along any length direction of each resistive or conductive path. Thus, the contact or wiper must be made of a material that is electrically, physically and environmentally compatible with the resistive and / or conductive tracks when an electrically active and physically dynamic system is present. The contacts or wipers also provide long useful life while maintaining uniform positive engagement with resistive or conductive elements, and should not produce polymers or debris that act as insulators and modify the output signal. do.

Contact or wiper materials currently used in such variable resistive devices consist of various clads or coated metal or precious metal alloys. In the dynamic state and when electrical activity is present, precious metals containing such contacts serve as catalysts to create debris and polymers that degrade the resistive track output signal. This leads to early termination of accurate performance and useful life.

Since wire elements are the most accurate device, metal contacts or wipers were initially used for winding resistive or metal conductive elements. Over time, significant improvements have been made in the area of non-wound products, and improved non-wound products have replaced the winding resistive elements, but in the presence of current and dynamic performance, the precious metal components of the metal contacts improve the accuracy of the output signal. Contacts or wipers have always caused problems with resistive elements because they provide a damaging polymer and a catalyst that creates debris.

Reduced size, improved accuracy, and reduced electrical contact resistance are now required in modern servo feedback positioning systems, and non-metallic contact materials must be considered to achieve the necessary and most necessary improvements in terms of these performance characteristics and removal of polymers and debris. do.

Therefore, improvements in electrical contacts and contact assemblies are needed, and therefore in particular improvements in materials and assemblies used.

It is therefore an object of the present invention to provide a contact or contact assembly for use in an electromechanical application that can effectively eliminate the aforementioned drawbacks inherent in a previously proposed system.

Another object of the present invention is to eliminate the above mentioned negative constraints and properties of known systems and to form contacts or wipers formed of non-metallic materials such as those formed from carbon fiber composite materials comprising carbon fibers and nonwoven carbon fiber mats. By providing a significantly improved service life of the system. These carbon fiber composite materials not only overcome the negative constraints caused by metal mixture contacts or wipers through special processing, but also significantly improve overall performance in all other respects.

It is an additional object of the present invention to significantly reduce the negative aspects inherent in the current state of the art manufacturing techniques and materials used in resistive and conductive track substrates and inherent in designs or materials currently used or previously proposed. To provide a wiper contact or contact assembly for use in an electromechanical component or application to be removed or removed.

According to one feature of the invention, existing contact carriers are adopted, and instead of the metal contacts previously used, the contacts are formed of a carbon fiber composite material which is in particular attached to the carrier.

According to one feature of the invention, a non-metallic electrical contact, such as made of a carbon fiber composite material, is suitable for the electrical material when properly disposed electrically conductively to transmit an unimpeded electrical signal along a longitudinal longitudinal direction. The core layer is processed and formed in a manner that allows multiple strands of carbon fiber. Such carbon fiber wires can be fused or conductively bonded by any of a variety of techniques that provide essentially uniform conductivity and redundant transmission of electrical signals. Additional off-axis electrical conductivity is provided by nonwoven carbon fiber mats disposed on the sides of the plurality of element wires of the carbon fiber. The carbon fiber composite material may be attached to the carrier or may be used without the carrier. Such carriers, if used, may be metal or nonmetal and may be attached to the carbon material composite using any of a variety of bonding, fusing, and fastening techniques. The carrier may also be electrically nonconductive depending on the application. Alternatively, the carrier may be formed of the same homogeneous carbon fiber composite material as used for the actual contact. Forming a carbon fiber contact layer made of a composite material is cross-layering the material in a non-parallel direction to provide additional structural stability and to support post-forming operations. ) May be associated with

The wiper contacts according to the invention are rigid enough to support and maintain a consistent position in relation to the resistive or conductive tracks of the substrate elements but sufficiently flexible at positions perpendicular to the track so that any change in movement is uniform. One contact position, spring rate and pressure can be maintained. Thus, the electrical output signal maintains its integrity.

According to an additional feature of the invention, the contact surface of the wiper contact adjacent to the resistive or conductive track consists of a plurality of contact points rather than a few metal bands or just one wide band of rigid beam contact. This ensures a more positive footprint in relation to resistive or conductive tracks, and reduces contact resistance and variable electrical noise.

The foregoing objects, features and advantages of the present invention and other objects, features and advantages will become apparent from the following detailed description of the embodiments and the accompanying drawings.

The present invention provides a contact or wiper element for transmitting electrical signals between resistive and / or conductive tracks and certain external circuit terminations in low voltage mode (up to 15 volts) or low current mode (up to 500 ma). In one embodiment, the contact or wiper element comprises one or more thin single layers of carbon fiber elements, all aligned in one direction, bonded together and of very low resistance for structural stability and electrical continuity. It is firmly fixed with a synthetic resin compound and forms part of the carbon fiber composite material described below. This fixation is arranged at one end of the electrical contact to secure the layer of carbon fiber elements together and to prevent relative movement in a fixed position such that the free ends of the electrical contact opposite the one end are associated with each other. By means of fastening means that can be moved.
Although various forms of carbon fiber bundles or strands are described in the following description of various embodiments of electrical contacts in accordance with the present invention, electrical contacts are described in the following with reference to FIGS. 13 and 14. It can be seen that it is formed of a material.

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As shown in FIGS. 1A-1C, the end of the contact or wiper can be specially formed to provide a force added, in particular to the engagement of the contact or wiper and the carbon fiber element better mates to the track of the device. To do it. In FIG. 1A, the contact 10 has a rake end 12. In FIG. 1B, the contact 14 has a knuckle end 16. In FIG. 1C, the contact 18 has a pointed end 20.

As shown in FIG. 1D, the contact or wiper 22 may also employ a mechanical strip 24 for support or attachment purposes. The mechanical strip 24 may or may not be electrically conductive, depending on the desired application.

2A, 2B, and 2C show the placement of carbon fiber bundles that are part of the composite material corresponding to FIGS. 1A, 1B, and 1C, respectively, and forming special end configurations 12, 16, and 20, respectively. That is, the enlarged view of FIG. 2A shows the carbon fiber bundles 26 arranged in one layer forming the rake end 12. Similarly, bundles 28 and 30 form knuckle ends 16 and pointed ends 20 respectively in FIGS. 2B and 2C, respectively. The remaining layers of the composite material are not shown because the construction of the carbon fiber bundle will be obscured.

In the embodiment of FIG. 3, the contact or wiper element 40 is formed of a carbon fiber matrix, wherein three adjacent carbon fiber layers 42, 44, 46 of the carbon fiber matrix are essentially perpendicular to each other. The carbon fibers forming the layers 42, 44, 46 are not tied but discretely placed within the shading matrix of the social parallel lines, and the fibers of the filtered layers are parallel to each other, but adjacent layers are essentially non-parallel and to each other. It can be perpendicular to.

4 shows a similarly configured contact 50 in which only one layer of carbon fibers in the contact 50 performs the actual contact and the inner layer 54 and the second outer layer are structurally supported. To provide. Additional layers of the composite material are shown in FIG. 14.

The matrix constructs shown in the embodiments of FIGS. 3 and 4 reinforce and reinforce fine carbon fiber strands to provide support for maintaining a stable contact position. Carbon fiber strands can be continuous or discontinuous and the matrix need not necessarily be homogeneous.

Corresponding to the structure shown in FIG. 1D, the matrix constructions of FIGS. 3 and 4 may use additional mechanical support strips and may be electrically conductive, depending on the desired application. The carbon fibers of the matrix constituents shown in FIGS. 3 and 4 are tightly fixed with very low resistance synthetic resin compounds to limit migration, add structural stability and provide multidirectional electrical continuity.

As shown in FIG. 5, the planar shape of the carbon fiber contact element 60 can be composed of a single layer rather than a matrix of carbon fiber wires, although the carbon fiber wires can be oriented more than 90 degrees. One is arranged in a horseshoe or inverted U-shape to provide a continuous and unbroken path from one arm 62 of the carbon fiber element element wire, shown at 64 to the other arm 66. In this embodiment, each carbon fiber wire 64 will be perpendicular and parallel to the resistive or conductive track, although not shown, and each opposing arm 62, 66 of continuous carbon fiber wire 64 is shown. However, it will contact essentially parallel parallel resistive or conductive tracks. Although not shown, the horseshoe type contact 60 may employ a carrier, which may or may not be electrically conductive, depending on the desired application.

A similar configuration is shown in FIG. 6 where the contact 70 has a right angle transition 72 in the path from one arm 74 to the other arm 76.

In the embodiment shown in FIG. 7, the contact assembly 80 is a very short strip 82 tightly conductively attached to 84 by a conductive adhesive to the parallel portion 84 of a thin beam 86 made of an electrically conductive material. A carbon fiber element formed as Such a beam structure provides a means for the current or voltage signal to flow unimpeded from the resistive or conductive track to the end end, whereby the compatible and desirable properties of the carbon fiber contact material are made of a non-carbon fiber material. It is coupled to the formed beam member. When using this embodiment, the carbon fiber element 82 will always be essentially perpendicular to the plane of the resistive or conductive tracks.

In the embodiment shown in FIGS. 2A, 2B, and 2C, the planar shape of the carbon fiber element is such that the free ends 12, 16, 20 of the carbon fiber elements 10, 14, 18 are resistive or conductive elements, respectively. And one or more parallel layers of carbon fiber strips arranged to be designated as ends to contact the tracks of. A feature of the present invention is that any other material, e.g., low resistance synthesis, for such lengths of 3/16 "or less, such that the ends 12, 16, 20 can only contact the actual track of the carbon fiber material Without resin compounds or the like, thereby improving mating between the ends 12, 16, 20 of the contacts 10, 14, 18 and the unshown tracks of the respective conductive elements. The free ends of the contacts may remain parallel to the same plane, or as shown in FIGS. 2A, 2B and 2C, the free ends may be bent or formed at an angle perpendicular to the main longitudinal direction of the strip, depending on the application. Can be formed or knuckle shaped.

In the embodiment shown in FIGS. 8, 9 and 10, each contact or wiper element 90, 92, 94 is made of narrow strips of carbon fiber elements, one of which is 96, 98, Shown at 100, each strip is less than 0.015 inches wide and consists of elemental wires of one or more parallel carbon fibers. Many such strips are arranged in a single plane and each strip is essentially parallel to each other but is not fused or chemically bonded. Multiple independent parallel strips are chemically associated with low resistance and electrically conductive synthetic resin compounds at one end of the strip that are mechanically captured and / or assembled by respective collars 102, 104, 106 in a single plane. In combination, a number of independent strip sections will be electrically uniform to the output signal and well accommodate additional assembly operation.

As shown in FIGS. 8, 9 and 10, the free ends 108, 110, 112 of each of the plurality of strip sections 90, 92, 94, which should function as adjacent contact points with the track of the resistive or conductive element. ) May remain coplanar with the strip and form as a rake as shown in FIG. 8, as a knuckle as shown in FIG. 9, or as another compatible contact geometry, such as a pin as shown in FIG. 10. Can be. This feature allows the assembly to include a plurality of contact strips, such as 96, 98, 100, each of which has relatively independent mechanical movement in a direction perpendicular to the resistive or conductive tracks of the substrate elements.

FIG. 11 is an embodiment similar to the embodiment of FIG. 7, with multiple layers 120, 122, 124 made of carbon fiber elements attached to the shorter legs 126 of the L-shaped carrier 128. The carbon fibers in each layer 120, 122, 124 are aligned substantially parallel, and the layers may be attached to the carrier by an electrically conductive synthetic resin compound shown approximately at 130.

As shown in the embodiment of Figures 3, 4 and 11, the electrical contact device is formed of multiple carbon fiber layers in various alignments. Similarly, all other embodiments shown and described herein may be formed of multiple layers. Various embodiments of the present invention may be used in a carrier that may or may not be electrically conductive, depending on the desired application.

Conversely, as shown in FIG. 12, the electrical contact or wiper 140 may be formed of only one carbon fiber element 142, which may be about 0.010 to 0.015 inches in thickness. Although the rake end 144 is provided in this embodiment, any of the remaining end treatments described above are suitable.

As mentioned above, all the embodiments described so far have a carbon fiber structure as core having a carbon fiber bundle disposed in one layer as shown in FIGS. 2A-2C or in multiple layers as shown in FIG. 3. It may be formed from a carbon fiber composite material.

As shown in FIG. 13, the layer of carbon fiber bundle 150 has mats 152, 154 formed of nonwoven carbon fibers disposed on each flat side. Although not shown in FIG. 13, after placing the mats 152, 154 on the carbon fiber bundle structure 150, thermoplastic resin is applied to the outer surface of the mats 152, 154. This thermoplastic resin, or polymer, completes the structure and adheres the mats 152, 154 to the carbon fiber bundle structure 150 to form a stable composite material. Nonwoven carbon fiber mat 152 or 154 is substantially isotropic, and the fibers are randomly placed to provide little or no directivity to the mat's plane.

Nonwoven carbon fiber mats provide a primary current that delivers capacity and also provide improved mechanical strength to the overall structure. More specifically, nonwoven carbon fibers provide a axial current that delivers off-axis mechanical strength and capacity, wherein the term "stock" refers to the longitudinal direction of the finally produced electrical contact.

Nonwoven carbon fiber mats are commercially available from the Hollingsworth & Vose Company in East Walpole, Massachusetts, with thicknesses ranging from 0.08 mm to 0.97 mm.

14 is a cross-sectional view of the assembled composite material 160 described above, wherein the nonwoven carbon fiber mats 152, 154 are disposed on the carbon fiber structure 150 and the thermoplastic resin layer 162 is the nonwoven carbon fiber layer 152. ) And a thermoplastic layer 164 is applied over the nonwoven carbon fiber mat 154. This results in a stable composite material that can be formed in any desired form, as described and illustrated in connection with some embodiments presented herein.

Of course, the foregoing description is provided by way of example only and is not intended to limit the spirit or scope of the invention, the scope of the invention is defined by the following claims.

Electrical contacts according to the present invention significantly improve the useful life of the system by providing a contact or wiper formed from a non-metallic material such as formed from a carbon fiber composite material comprising a carbon fiber and a nonwoven carbon fiber mat. These carbon fiber composite materials not only overcome the negative constraints caused by metal mixture contacts or wipers through special processing, but also significantly improve overall performance in all other respects.

Electrical contacts according to the present invention are better compatible with the current state of the art manufacturing techniques and materials used in resistive and conductive track substrates and significantly reduce the negative aspects inherent in designs or materials currently used or previously proposed. It provides a wiper contact or contact assembly for use in an electromechanical component or application that removes or removes.

Claims (20)

An electrical device for transmitting electrical signals and for making movable contact with electrically conductive tracks, At least one layer 150 of carbon fiber elements aligned in substantially the same direction; First and second mats (152, 154) formed of nonwoven carbon fibers and sandwiching the layers of carbon fiber elements; And Thermoplastic coatings 162 and 164 added on the outer surface of the mats An electrical contact formed of a composite carbon fiber material comprising: Wherein the carbon fiber elements of each layer are glued together so that the free ends 12, 16, 20; 108, 110, 112 of the layer of carbon fiber elements are arranged in contact with an electrically conductive track. Device. The method of claim 1, And wherein the electrical contact further comprises a support strip (24, 88, 128) adhered thereto by a synthetic resin compound. The method of claim 2, And the support strip is electrically conductive. The method of claim 2, And the electrical contact is attached to the shorter leg (126) of the L-shaped strip. The method of claim 1, And said free ends of said layer of carbon fiber elements are formed in a knuckle shape (16, 110). The method of claim 1, And said free ends of said layer of carbon fiber elements are formed in an indented shape (20, 112). The method of claim 1, Further comprising collars 102, 104, 106 disposed on either side of the thermoplastic coating opposite the free ends and on the first mat and the second mat at ends retracted from the free ends. An electric device, characterized in that. An electrical device for transmitting electrical signals and for making movable contact with electrically conductive tracks, At least one layer 150 of carbon fiber elements aligned in substantially the same direction, first mats and second mats 152, 154 formed of nonwoven carbon fibers and sandwiching the layers of carbon fiber elements, and the An electrical contact formed of a carbon fiber composite material having thermoplastic coatings 162 and 164 added on the outer surface of the mats; And The layers of carbon fiber elements are held together at one end of the electrical contact to secure the layer together and to prevent relative movement in the fixed position so that the free ends of the electrical contact opposite the one end are moved relative to each other. Electrical devices comprising collars (102, 104, 106). The method of claim 8, And said free ends of said layer of carbon fiber elements are formed in a knuckle shape (16, 110). The method of claim 8, And said free ends of said layer of carbon fiber elements are formed in an indented shape (20, 112). An electrical device for transmitting electrical signals and for making movable contact with electrically conductive tracks, At least one layer 150 of carbon fiber elements aligned in substantially the same direction, first mats and second mats 152, 154 formed of nonwoven carbon fibers and sandwiching the layers of carbon fiber elements, and the An electrical contact formed of a carbon fiber composite material having thermoplastic coatings 162 and 164 added on the outer surface of the mats, The electrical contact has a first arm portion 74, the carbon fiber elements are substantially aligned in a first direction, and the second arm portion 76 is disposed away from the same plane as the first arm portion, The carbon fiber elements of the second arm portion are substantially aligned in the first direction, and a transition portion 72 connects first ends of each of the first arm portion and the second arm portion, and the transition portion The carbon fiber elements are substantially aligned with each other in a second direction different from the first direction of the first arm portion and the second arm portion, and a second of the first arm portion and the second arm portion opposite the first ends. And end portions in contact with the electrically conductive tracks. The method of claim 11, The transition portion is disposed at right angles to the first arm portion and the second arm portion, the second direction being substantially perpendicular to the first direction. The method of claim 11, The transition portion is semicircular in shape and on the same plane as the first and second arm portions. An electrical device for transmitting electrical signals and for making movable contact with electrically conductive tracks, A plurality of overlying layers 150 of carbon fibers formed as a matrix 150, 42, 44, 46, a first mat and a second mat 152, 154 formed of nonwoven carbon fibers and sandwiching the layers of carbon fibers therebetween, And an electrical contact formed of a carbon fiber composite material having a thermoplastic coating 162, 164 added on the outer surface of the mats, wherein the carbon fibers present in each of the plurality of layers are substantially parallel. Aligned so that adjacent layers are aligned such that the carbon fibers in the adjacent layer are not substantially parallel, And wherein the electrically conductive synthetic resin compound binds the carbon fibers in each layer together such that the plurality of overlying layers solidify the electrical contact. The method of claim 14, The electrical contact is formed to have a transition portion and a first arm portion 74 and a second arm portion 76 extending from the transition portion 72, wherein the free ends of the first and second arm portions are electrically conductive. An electrical device in contact with the track. The method of claim 15, And the free ends are formed in a rake shape. The method of claim 15, And said plurality of overlying layers span the same space. The method of claim 15, And the first and second arm portions are formed from a single layer of carbon fibers. An electrical device for transmitting electrical signals and for making movable contact with electrically conductive tracks, Electrically conductive carriers 88 and 128; And A plurality of layers 150 of carbon fiber elements 150 disposed on and attached to the carrier, first mats and second mats 152 formed of nonwoven carbon fibers and sandwiching the layers of carbon fiber elements therebetween; 154, and an electrical contact formed of a carbon fiber composite material having thermoplastic coatings 162 and 164 added on the outer surface of the mats, wherein the carbon fiber elements in each layer are aligned in substantially the same direction and the And the free ends of the carbon fiber elements contact the electrically conductive track. The method of claim 19, Wherein the carrier is substantially L-shaped and the plurality of layers of carbon fiber elements are attached to the shorter leg (126) of the L-shaped carrier.

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