US3525006A - Carbon fibre brush - Google Patents
Carbon fibre brush Download PDFInfo
- Publication number
- US3525006A US3525006A US709444A US3525006DA US3525006A US 3525006 A US3525006 A US 3525006A US 709444 A US709444 A US 709444A US 3525006D A US3525006D A US 3525006DA US 3525006 A US3525006 A US 3525006A
- Authority
- US
- United States
- Prior art keywords
- fibres
- brush
- carbon
- carbon fibre
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R39/00—Rotary current collectors, distributors or interrupters
- H01R39/02—Details for dynamo electric machines
- H01R39/18—Contacts for co-operation with commutator or slip-ring, e.g. contact brush
- H01R39/24—Laminated contacts; Wire contacts, e.g. metallic brush, carbon fibres
Definitions
- a carbon brush comprising an aligned array of juxtaposed carbon or graphite fibres wherein the contact surface of said brush is formed by the ends of said fibres.
- the fibres may be bonded to each other for a part of their length either by means of an epoxy resin or by electroplating the ends of said fibres.
- This invention relates to electrical brushes having an improved current carrying capacity by means of more efiicient surface contact.
- a carbon brush comprises an aligned array of juxtaposed carbon or graphite fibres wherein the contact surface of the brush is formed by the ends of the fibres.
- an aligned array of juxtaposed carbon or graphite fibres 1, which are bonded to each other over a portion of their length 2 by an epoxide resin, are encapsulated in a soft metal can 3 open at one end. Electrical conductivity at the non-contact end of the brush is ensured by electro-plating the ends 4 of the fibres which in turn are soldered to the closed end of the can 5.
- Carbon brushes of dimensions /2" x 1" x 2 long have been produced in accordance with the invention.
- Sufficient carbon or graphite fibres of suitable length and diameter are placed in a three sided metal container and compressed with the fibres protruding from the container by about at one end and about 4 at the other.
- the fourth side of the container is then crimped and soldered into position whilst the fibres are under compression.
- the assembly is then placed vertically in a vessel containing diluted epoxy resin (e.g. Araldite MY 753 (registered trademark) diluted with %-10% acetone) in such a manner that resin is drawn, by capillary attraction, into the fibres to a predetermined height.
- diluted epoxy resin e.g. Araldite MY 753 (registered trademark) diluted with %-10% acetone
- Excess resin is then removed and the resin-bond end of the fibre block faced level with the container to expose the ends of the fibres, which are electroplated to a continuous sheet of copper and then tinned with 60/40 solder.
- the end closure of the container, which has been previously tinned, is then folded down to meet the tinned end of the fibre block and the whole sweated together.
- a flexible electrical connection is then soldered to the container as desired.
- a suitable material for the container or can is copper sheet of 0.02 in gauge for this size of brush.
- small brushes in length by A" x 1" have been made without the use of epoxy resin.
- the fibres are encapsulated in a copper container as previously described and the assembly is then placed vertically in a copper plating bath. Electrolyte is drawn into the bundle of fibres by capillary attraction and the ends of the fibres are plated to a depth of .005. Further time in the plating bath results in the encasement of the ends of the fibres in a continuous matrix of copper, which is then tinned with /40 solder and the end closure of the container, which has been previously tinned, is then folded down to meet the tinned end of the fibre block and the whole sweated together.
- control of the build-up of resistive oxide films on the commutator can be accomplished by the introduction of a selected number of fibres in the brush (e.g. glass, metals or other abrasive materials) to impart a limited degree of wear.
- a selected number of fibres in the brush e.g. glass, metals or other abrasive materials
- a carbon brush comprising an aligned array of juxtaposed carbon fibres wherein the contact surface of said brush is formed by the ends of said fibres said array including a number of fibres of abrasive material.
- a carbon brush comprising an aligned array of juxtaposed carbon fibres wherein the contact surface of said brush is formed by the ends of said fibres said fibres being bonded to each other for a part of their length by an epoxy resin.
Description
Aug. 18, 1970 L, ETAL CARBON FIBRE BRUSH Filed Feb. 29, 1968 QIQQ United States Patent Oflice 3,525,006 Patented Aug. 18, 1970 3,525,006 CARBON FIBRE BRUSH Norman Lawrence Parr, Wareham, Dorset, Sam Bolshaw,
Bath, Somerset, and Edwin Richard Wells May, Moordown, Bournemouth, England, assignors to National Research Development Corporation, London, England, a British corporation Filed Feb. 29, 1968, Ser. No. 709,444 Int. Cl. H011 39/26 U.S. Cl. 310251 4 Claims ABSTRACT OF THE DISCLOSURE A carbon brush comprising an aligned array of juxtaposed carbon or graphite fibres wherein the contact surface of said brush is formed by the ends of said fibres. The fibres may be bonded to each other for a part of their length either by means of an epoxy resin or by electroplating the ends of said fibres.
This invention relates to electrical brushes having an improved current carrying capacity by means of more efiicient surface contact.
According to the present invention a carbon brush comprises an aligned array of juxtaposed carbon or graphite fibres wherein the contact surface of the brush is formed by the ends of the fibres.
Referring, by way of example, to the accompanying drawing, which illustrates a brush according to the present invention, an aligned array of juxtaposed carbon or graphite fibres 1, which are bonded to each other over a portion of their length 2 by an epoxide resin, are encapsulated in a soft metal can 3 open at one end. Electrical conductivity at the non-contact end of the brush is ensured by electro-plating the ends 4 of the fibres which in turn are soldered to the closed end of the can 5.
Carbon brushes of dimensions /2" x 1" x 2 long have been produced in accordance with the invention. Sufficient carbon or graphite fibres of suitable length and diameter are placed in a three sided metal container and compressed with the fibres protruding from the container by about at one end and about 4 at the other. The fourth side of the container is then crimped and soldered into position whilst the fibres are under compression. The assembly is then placed vertically in a vessel containing diluted epoxy resin (e.g. Araldite MY 753 (registered trademark) diluted with %-10% acetone) in such a manner that resin is drawn, by capillary attraction, into the fibres to a predetermined height. The whole is then allowed to stand" until the resin cures. Excess resin is then removed and the resin-bond end of the fibre block faced level with the container to expose the ends of the fibres, which are electroplated to a continuous sheet of copper and then tinned with 60/40 solder. The end closure of the container, which has been previously tinned, is then folded down to meet the tinned end of the fibre block and the whole sweated together. A flexible electrical connection is then soldered to the container as desired. A suitable material for the container or can is copper sheet of 0.02 in gauge for this size of brush.
Experience has shown that resistance heating in individual fibres can lead to overheating of the brush and thus produce degradation of the epoxy resin. It has been found that this can be overcome by using shortened brushes and by bonding the fibres at the non-contaot end of the brush by low energy copper electro-plating of the tips of the fibres and thereby dispensing with the need to anchor the fibres with epoxy resin.
'In one example, small brushes in length by A" x 1" have been made without the use of epoxy resin. The fibres are encapsulated in a copper container as previously described and the assembly is then placed vertically in a copper plating bath. Electrolyte is drawn into the bundle of fibres by capillary attraction and the ends of the fibres are plated to a depth of .005. Further time in the plating bath results in the encasement of the ends of the fibres in a continuous matrix of copper, which is then tinned with /40 solder and the end closure of the container, which has been previously tinned, is then folded down to meet the tinned end of the fibre block and the whole sweated together.
It has also been found that control of the build-up of resistive oxide films on the commutator can be accomplished by the introduction of a selected number of fibres in the brush (e.g. glass, metals or other abrasive materials) to impart a limited degree of wear.
We claim:
1. A carbon brush comprising an aligned array of juxtaposed carbon fibres wherein the contact surface of said brush is formed by the ends of said fibres said array including a number of fibres of abrasive material.
2. A carbon brush according to claim 1 wherein said abrasive fibres are of glass.
3. A carbon brush comprising an aligned array of juxtaposed carbon fibres wherein the contact surface of said brush is formed by the ends of said fibres said fibres being bonded to each other for a part of their length by an epoxy resin.
4. A carbon brush according to claim 3 wherein said array includes a number of fibres of abrasive material.
References Cited UNITED STATES PATENTS 539,453 5/1895 Thomson 310--248 539,454 5/1895 Thomson 310-248 3,382,387 5/1968 Marshall 310-248 MILTON O. HIRSHFIELD, Primary Examiner L. L. SMITH, Assistant Examiner U.S. C1. X.R. 310252
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US70944468A | 1968-02-29 | 1968-02-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3525006A true US3525006A (en) | 1970-08-18 |
Family
ID=24849871
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US709444A Expired - Lifetime US3525006A (en) | 1968-02-29 | 1968-02-29 | Carbon fibre brush |
Country Status (1)
Country | Link |
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US (1) | US3525006A (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3668451A (en) * | 1970-08-14 | 1972-06-06 | Ian Roderick Mcnab | Electrical brush structure |
US3786292A (en) * | 1972-04-26 | 1974-01-15 | Morganite Carbon Ltd | An electrical contact brush assembly with anti-vibration head |
US3818588A (en) * | 1972-03-30 | 1974-06-25 | Nat Res Dev | Electrical brushes |
US3886386A (en) * | 1973-08-01 | 1975-05-27 | Gen Electric | Carbon fiber current collection brush |
US4000430A (en) * | 1973-02-13 | 1976-12-28 | Vladimir Alexeevich Bely | Contact brush |
US4306169A (en) * | 1978-04-20 | 1981-12-15 | Siemens Aktiengesellschaft | Current transfer brush |
US4349760A (en) * | 1979-10-31 | 1982-09-14 | Siemens Aktiengesellschaft | Current transfer brush with graphite foils |
US4398113A (en) * | 1980-12-15 | 1983-08-09 | Litton Systems, Inc. | Fiber brush slip ring assembly |
US4576082A (en) * | 1982-12-23 | 1986-03-18 | Westinghouse Electric Corp. | Linear fiber armature for electromagnetic launchers |
DE19929686A1 (en) * | 1999-06-28 | 2001-01-25 | Christian Felber | Brush ring for electric motor e.g. for machine tools, has current-conducting contact element consisting of fine, current-conducting fibres, preferably carbon fibres, fixed in current-conducting bearer element |
US20070145853A1 (en) * | 2005-12-22 | 2007-06-28 | Hon Hai Precision Industry Co., Ltd. | Electrical brush and method for making the same |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US539454A (en) * | 1895-05-21 | Carbon brush | ||
US539453A (en) * | 1895-05-21 | Carbon brush | ||
US3382387A (en) * | 1968-05-07 | Gen Electric | Electrical current collection and delivery method and apparatus |
-
1968
- 1968-02-29 US US709444A patent/US3525006A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US539454A (en) * | 1895-05-21 | Carbon brush | ||
US539453A (en) * | 1895-05-21 | Carbon brush | ||
US3382387A (en) * | 1968-05-07 | Gen Electric | Electrical current collection and delivery method and apparatus |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3668451A (en) * | 1970-08-14 | 1972-06-06 | Ian Roderick Mcnab | Electrical brush structure |
US3818588A (en) * | 1972-03-30 | 1974-06-25 | Nat Res Dev | Electrical brushes |
US3786292A (en) * | 1972-04-26 | 1974-01-15 | Morganite Carbon Ltd | An electrical contact brush assembly with anti-vibration head |
US4000430A (en) * | 1973-02-13 | 1976-12-28 | Vladimir Alexeevich Bely | Contact brush |
US3886386A (en) * | 1973-08-01 | 1975-05-27 | Gen Electric | Carbon fiber current collection brush |
US4306169A (en) * | 1978-04-20 | 1981-12-15 | Siemens Aktiengesellschaft | Current transfer brush |
US4349760A (en) * | 1979-10-31 | 1982-09-14 | Siemens Aktiengesellschaft | Current transfer brush with graphite foils |
US4398113A (en) * | 1980-12-15 | 1983-08-09 | Litton Systems, Inc. | Fiber brush slip ring assembly |
US4576082A (en) * | 1982-12-23 | 1986-03-18 | Westinghouse Electric Corp. | Linear fiber armature for electromagnetic launchers |
DE19929686A1 (en) * | 1999-06-28 | 2001-01-25 | Christian Felber | Brush ring for electric motor e.g. for machine tools, has current-conducting contact element consisting of fine, current-conducting fibres, preferably carbon fibres, fixed in current-conducting bearer element |
US20070145853A1 (en) * | 2005-12-22 | 2007-06-28 | Hon Hai Precision Industry Co., Ltd. | Electrical brush and method for making the same |
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