US3067318A - Metal-graphite brush with brazed shunt - Google Patents
Metal-graphite brush with brazed shunt Download PDFInfo
- Publication number
- US3067318A US3067318A US852079A US85207959A US3067318A US 3067318 A US3067318 A US 3067318A US 852079 A US852079 A US 852079A US 85207959 A US85207959 A US 85207959A US 3067318 A US3067318 A US 3067318A
- Authority
- US
- United States
- Prior art keywords
- brush
- shunt
- metal
- brazing
- graphite
- 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
Links
- 229910002804 graphite Inorganic materials 0.000 title claims description 25
- 239000010439 graphite Substances 0.000 title claims description 25
- 238000005219 brazing Methods 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 13
- 229910045601 alloy Inorganic materials 0.000 claims description 12
- 239000000956 alloy Substances 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 239000002923 metal particle Substances 0.000 claims description 5
- 238000005304 joining Methods 0.000 claims description 3
- 239000007770 graphite material Substances 0.000 claims description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 28
- 229910052802 copper Inorganic materials 0.000 description 24
- 239000010949 copper Substances 0.000 description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 23
- 238000010438 heat treatment Methods 0.000 description 11
- 239000011133 lead Substances 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 239000013528 metallic particle Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000011135 tin Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000004020 conductor Substances 0.000 description 4
- PSFDQSOCUJVVGF-UHFFFAOYSA-N harman Chemical compound C12=CC=CC=C2NC2=C1C=CN=C2C PSFDQSOCUJVVGF-UHFFFAOYSA-N 0.000 description 4
- 239000012255 powdered metal Substances 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910000967 As alloy Inorganic materials 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R43/00—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors
- H01R43/12—Manufacture of brushes
Definitions
- This invention relates to an improved brush assembly comprising a metal-graphite brush with an attached shunt, and to an improved method of fabricating such brush assemblies.
- Metal-graphite brushes are known to the art.
- the brush is formed from a mixture of powdered metal and powdered graphite molded into the desired final form, or cut into the desired final form from a larger block of material.
- the powdered metal may be entirely copper, although other metallic particles, such as tin, lead, zinc and silver, may be used in combination with copper.
- Such brushes offer the requisite low conductivity, current handling capability and suitable contact resistance.
- the graphite particles in the brush lubricate the bearing surface of the brush as it rides on the contact surface, such as a commutator, and prevent welding of the brush to the surface by the intermittent arcs encountered in operation.
- a shunt or wire conductor is affixed to the brush.
- the shunt is generally a rope-stranded conductor formed of copper strands, tin-coated copper strands, or zinc-coated copper strands.
- the size and type of wire is determined by the application intended, and the wire is selected primarily on the basis of strength, current carrying capacity and flexibility. In a few applications it has been found desirable to use a solid instead of a stranded conductor.
- the art has resorted to drilling a hole in the brush, inserting one end of the shunt therein, and ⁇ ramp-packing the hole with a powder such as copper powder, or silver-coated copper powder. While such tamped shunt connection may give the requisite mechanical and electrical bond, such method of assembly results in brushes of higher than desired expense.
- the art has also resorted to riveting or bolting the shunt to the brush, or to attaching the shunt to a conductive contact which is riveted or bolted to the brush.
- the graphite particles in the brush composition serve to prevent welding of the commutator to the brush in the equipment for which the brush is designed. Therefore, it would seem that the graphite content of the brush would also preclude brazing of the shunt thereto. Surprisingly, however, it has been found that the shunt can be brazed to the brush with the desired mechanical and electrical bond. This startling and unusual result is unexpected and offers important advantages over the processes used by the art.
- a brush formed of metallic and graphite particles 3,E ?,3i-3 Fatented Dec. 4, 1962 formed into the shape desired for the application intended.
- a shunt of rope-stranded copper wire is brazed thereto.
- the metalgraphite brush and the shunt are orientated in the desired relative positions.
- a brazing compound is applied at the joint.
- the shunt and brush are then held in position and heated to braze the shunt to the brush.
- the shunt is thus brazed to the copper in the brush to provide a brush assembly of low fabrication cost.
- FIGURE 1 is aperspective view of a brush assembly fabricated in accordance with this invention.
- FIGURE 2 is a partially sectioned perspective view of a brush assembly within heating electrodes illustrating the method of fabrication of the brush assembly shown in FIGURE 1.
- FIGURE 3 is a perspective view of another embodiment of a brush assembly in accordance with this invention.
- FIGURE 4 is a partially sectioned perspective view of a brush assembly within heating electrodes illustrating the method of fabricating the brush assembly shown in FIGURE 3.
- FIGURES l and 2 there is shown a brush It ⁇ to one side surface of which is to be attached the shunt 12.
- the brush may be formed from a mixture of a powdered metal and powdered graphite molded into the shape desired for the application intended.
- the powdered metal used in fabricating the brush will comprise copper.
- other metals may be used in combination with the copper such as tin, lead, zinc and silver.
- Illustrative of the compositions used in typical brushes employed by the art are the compositions set forth in Table I.
- Table I (1) 77% copper, 18% lead, 5% graphite (2) 93% copper, 7% graphite (3) copper, 10% tin, 8% lead, 7% graphite (4) 77% copper, 15% lead, 8% graphite (5) copper, 5% tin, 10% graphite (6) 82% copper, 5% tin, 3% zinc, 10% graphite (7) 84% copper, 3% lead, 13% graphite (8) 75% copper, 25% lead.
- the majority of brushes are formed with a relatively high percentage of metallic component. These brushes are widely used by industry.
- the shunt to be attached to the brush may be a copper Wire.
- the shunt is a flexible rope stranded copper conductor selected primarily on the basis of strength, current carrying capacity and flexibility needed for the application intended.
- a copper 743.0O5 shunt may be employed for certain brushes.
- the numerals identify respectively the number of ropes, the number of strands or wires in each rope, and the diameter of each strand (e.g. 7 ropes, each having 43 strands of 0.005-in. diameter wire).
- the shunt is to be aflixed to one side of the brush. To do this one end of the shunt is merely brazed on face 14 of the brush.
- a brazing compound such as a brazing alloy preform I5
- the brazing agents must be suitable for brazing the metals contained in the brush. Such brazing agents are readily available in strip, wire paste, and powdered form.
- the agent may be applied to the brush and to the shunt or placed between the two prior to heating. Illustrative of agents successfully appliable in this application are those listed in Table II.
- the brazed joint is formed in the electric resistance unit having a base electrode 16 and a top electrode 18.
- the brush rests on the base electrode; the other electrode 18 being positioned so that the shaped face 20 thereof is vertically above the shunt lead 12.
- the electrodes 1% and 17 may be formed of tungsten, molybdenum or other suitable material.
- the heating unit electrode 1.8 is then moved down to contact the wire shunt 12.
- the shaped face 20 thereof ensures an evenly distributed pressure contact against the round shunt. When the electrodes are closed, heating current is passed therebetween to braze the shunt to the brush.
- a copper 743.005 shunt was brazed to a brush composed of 93 percent copper and 7 percent graphite.
- the heating unit was a modified spot welder with the voltage and contact pressure between the electrodes reduced to just below the arcing point.
- the brazing alloy comprised Sil-Fos in ribbon form inserted between the brush material and the shunt.
- the force closing of the electrodes was 70 pounds.
- Brazing current was established at 7400 amperes and held for a brazing time of 15 cycles A see.) with a total hold time of cycles 0/: sec.).
- Brush assemblies so fabricated were found to have a maximum electrical resistance at the bond of 52 micro ohms.
- the mechanical bond required a force of at least 50 pounds to separate the shunt from the brush. It should be noted that in the separation, the brush material was fractured indicating that the welded bond was even stronger than the separation strength of the brush material. It will be further noted that these values equal or exceed those obtained with a tamped shunt connection of the same materials.
- a surface preparation of the brush and shunt will depend greatly upon the materials employed and upon the brazing compound used. For example, when joining a copper shunt to a brush having a high copper content many brazing compounds are available which do not require fluxing. In other applications a suitable flux may be required for a proper bond.
- the shunt is apparently brazed to the metallic particles in the brush to provide a mechanical and electrical bond between the brush and the shunt.
- This conclusion is supported by the fracturing of the brush material when the shunt is pulled from the brush. While this conclusion seems justified by observation of the results, the startling results obtained by this invention and the departure of the invention from the practices of the prior art caution against acceptance of this conclusion as the full explanation. However, whatever the reasons, the results are not disputable.
- the strength of the brazed connection depends essentially on the contact area between the shunt and the metallic particles in the brush. The mechanical strength of the bond is decreased with a decrease in the percentage of the metallic particle component of the brush.
- FIGURES 3 and 4 may advantageously be employed.
- FIGURES 3 and 4 there is shown a brush 22 molded from a mixture of powdered metallic particles and powdered graphite and having a slot 24 molded or cut in the face thereof.
- the shunt 26 is positioned within a slot with a brazing alloy, such as alloy preform 27, positioned between the shunt and the brush.
- the brush is then placed within the resistance heating unit and heating current passed between the electrodes 16 and 18 thereof to braze the shunt to the brush.
- the electrode is provided with an electrode tip 28 which will fit within the slot and contact the shunt over the peripheral surface thereof.
- the brush After passage of the heating current the brush will be brazed both to the bottom and the sides of the slot.
- the increase in the brazed contact area is advantageous in providing greater mechanical strength and increased electrical conductivity over the embodiment wherein the shunt is afiixed to the side of the brush.
- the additional metal provided by the brazing agent is effective in increasing the area of contact between the shunt and the metal particles of the brush to give the requisite mechanical strength and electrical conductivity at the bond.
- the method of joining a shunt to a metal-graphite brush by heat supplied by current from electrode means which method consists of the steps of positioning the shunt adjacent to the brush with a brazing alloy in position to join confronting faces of the shunt and brush, holding the shunt, brush and brazing alloy with said confronting faces pressed together under substantial pressure, maintaining the pressure by force exerted by the electrode means and evenly distributed over the area of contact with the electrode means, then Connecting the shunt to the metal particles of the brush by electric resistance brazing produced by current passed through the brush, shunt and brazing alloy from said electrode means with the current and brazing time limited to prevent damage to the metal-graphite material, the additional metal provided by the brazing alloy being efiective in increasing the area of contact between the shunt and the metal particles of the brush.
- brazing alloy is a silver solder brazing alloy.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Motor Or Generator Current Collectors (AREA)
Description
Dec. 4, 1962 H. E. HANES 3,067,318.
' METAL-GRAPHITE BRUSH WITH BRAZED SHUNT Filed Nov. 10, 1959 I W Q9? f INVENTOR.
BY HERMAN E- HANES fl 44 482241 Kw #M AT TOR NE Y5 York Filed 1d, 1959, Ser. No. 852,tl'79 4 Claims. (Ci. 219--85) This invention relates to an improved brush assembly comprising a metal-graphite brush with an attached shunt, and to an improved method of fabricating such brush assemblies.
Metal-graphite brushes are known to the art. The brush is formed from a mixture of powdered metal and powdered graphite molded into the desired final form, or cut into the desired final form from a larger block of material. The powdered metal may be entirely copper, although other metallic particles, such as tin, lead, zinc and silver, may be used in combination with copper.
Such brushes offer the requisite low conductivity, current handling capability and suitable contact resistance. The graphite particles in the brush lubricate the bearing surface of the brush as it rides on the contact surface, such as a commutator, and prevent welding of the brush to the surface by the intermittent arcs encountered in operation.
In order to bring electrical connections from the brush to the operating equipment, a shunt or wire conductor is affixed to the brush.
The shunt is generally a rope-stranded conductor formed of copper strands, tin-coated copper strands, or zinc-coated copper strands. The size and type of wire is determined by the application intended, and the wire is selected primarily on the basis of strength, current carrying capacity and flexibility. In a few applications it has been found desirable to use a solid instead of a stranded conductor.
In order to connect the shunt to the brush with the requisite mechanical strength and with the requisite low resistance bond, the art has resorted to drilling a hole in the brush, inserting one end of the shunt therein, and {ramp-packing the hole with a powder such as copper powder, or silver-coated copper powder. While such tamped shunt connection may give the requisite mechanical and electrical bond, such method of assembly results in brushes of higher than desired expense.
The art has also resorted to riveting or bolting the shunt to the brush, or to attaching the shunt to a conductive contact which is riveted or bolted to the brush.
While all of these methods give the requisite firm mechanical attachment of the shunt to the brush wtih a connection of low electrical resistance, it is apparent that the complications of assembly thereof increase the cost of the brush.
It is therefore the primary object of this invention to provide an improved brush assembly comprising a metalgraphite brush and a shunt affixed thereto by brazing.
It is a further object of this invention to provide an improved method for attaching a shunt to a metal-graphite brush.
The graphite particles in the brush composition serve to prevent welding of the commutator to the brush in the equipment for which the brush is designed. Therefore, it would seem that the graphite content of the brush would also preclude brazing of the shunt thereto. Surprisingly, however, it has been found that the shunt can be brazed to the brush with the desired mechanical and electrical bond. This startling and unusual result is unexpected and offers important advantages over the processes used by the art.
In a preferred embodiment of this invention there is provided a brush formed of metallic and graphite particles 3,E ?,3i-3 Fatented Dec. 4, 1962 formed into the shape desired for the application intended. A shunt of rope-stranded copper wire is brazed thereto.
To practice the method of this invention, the metalgraphite brush and the shunt are orientated in the desired relative positions. A brazing compound is applied at the joint. The shunt and brush are then held in position and heated to braze the shunt to the brush. The shunt is thus brazed to the copper in the brush to provide a brush assembly of low fabrication cost.
A brush assembly and the method of fabrication thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings of which:
FIGURE 1 is aperspective view of a brush assembly fabricated in accordance with this invention.
FIGURE 2 is a partially sectioned perspective view of a brush assembly within heating electrodes illustrating the method of fabrication of the brush assembly shown in FIGURE 1.
FIGURE 3 is a perspective view of another embodiment of a brush assembly in accordance with this invention, and
FIGURE 4 is a partially sectioned perspective view of a brush assembly within heating electrodes illustrating the method of fabricating the brush assembly shown in FIGURE 3.
In FIGURES l and 2 there is shown a brush It} to one side surface of which is to be attached the shunt 12.
The brush may be formed from a mixture of a powdered metal and powdered graphite molded into the shape desired for the application intended. The powdered metal used in fabricating the brush will comprise copper. However, other metals may be used in combination with the copper such as tin, lead, zinc and silver. Illustrative of the compositions used in typical brushes employed by the art are the compositions set forth in Table I.
Table I (1) 77% copper, 18% lead, 5% graphite (2) 93% copper, 7% graphite (3) copper, 10% tin, 8% lead, 7% graphite (4) 77% copper, 15% lead, 8% graphite (5) copper, 5% tin, 10% graphite (6) 82% copper, 5% tin, 3% zinc, 10% graphite (7) 84% copper, 3% lead, 13% graphite (8) 75% copper, 25% lead As will be noted from Table I, the majority of brushes are formed with a relatively high percentage of metallic component. These brushes are widely used by industry.
the shunt to be attached to the brush may be a copper Wire. In the usual case the shunt is a flexible rope stranded copper conductor selected primarily on the basis of strength, current carrying capacity and flexibility needed for the application intended. For example, a copper 743.0O5 shunt may be employed for certain brushes. The numerals identify respectively the number of ropes, the number of strands or wires in each rope, and the diameter of each strand (e.g. 7 ropes, each having 43 strands of 0.005-in. diameter wire).
In the application shown in FIGURES 1 and 2, the shunt is to be aflixed to one side of the brush. To do this one end of the shunt is merely brazed on face 14 of the brush. A brazing compound, such as a brazing alloy preform I5, is positioned at the joint between the shunt and the face of the brush. The brazing agents must be suitable for brazing the metals contained in the brush. Such brazing agents are readily available in strip, wire paste, and powdered form. The agent may be applied to the brush and to the shunt or placed between the two prior to heating. Illustrative of agents successfully appliable in this application are those listed in Table II.
Table I1 Sil-Fos, Handy and Harman, melting point 1185-1300" F. Easy-Flo, Handy and Harman, melting point 1125- To hraze the shunt to the brush, the brazed joint is formed in the electric resistance unit having a base electrode 16 and a top electrode 18. The brush rests on the base electrode; the other electrode 18 being positioned so that the shaped face 20 thereof is vertically above the shunt lead 12. The electrodes 1% and 17 may be formed of tungsten, molybdenum or other suitable material.
The heating unit electrode 1.8 is then moved down to contact the wire shunt 12. The shaped face 20 thereof ensures an evenly distributed pressure contact against the round shunt. When the electrodes are closed, heating current is passed therebetween to braze the shunt to the brush.
As an example of a specific operation, but not by way of limitation of this invention, a copper 743.005 shunt was brazed to a brush composed of 93 percent copper and 7 percent graphite. The heating unit was a modified spot welder with the voltage and contact pressure between the electrodes reduced to just below the arcing point. The brazing alloy comprised Sil-Fos in ribbon form inserted between the brush material and the shunt. The force closing of the electrodes was 70 pounds. Brazing current was established at 7400 amperes and held for a brazing time of 15 cycles A see.) with a total hold time of cycles 0/: sec.). Brush assemblies so fabricated were found to have a maximum electrical resistance at the bond of 52 micro ohms. The mechanical bond required a force of at least 50 pounds to separate the shunt from the brush. It should be noted that in the separation, the brush material was fractured indicating that the welded bond was even stronger than the separation strength of the brush material. It will be further noted that these values equal or exceed those obtained with a tamped shunt connection of the same materials.
It will be noted that in addition to electric resistance heating that other conventional heating, such as by incandescent carbon electrodes, may be employed in the practice of this invention.
A surface preparation of the brush and shunt will depend greatly upon the materials employed and upon the brazing compound used. For example, when joining a copper shunt to a brush having a high copper content many brazing compounds are available which do not require fluxing. In other applications a suitable flux may be required for a proper bond.
Although it would be expected that the graphite would prevent an adequate brazed bond, the shunt is apparently brazed to the metallic particles in the brush to provide a mechanical and electrical bond between the brush and the shunt. This conclusion is supported by the fracturing of the brush material when the shunt is pulled from the brush. While this conclusion seems justified by observation of the results, the startling results obtained by this invention and the departure of the invention from the practices of the prior art caution against acceptance of this conclusion as the full explanation. However, whatever the reasons, the results are not disputable. The strength of the brazed connection depends essentially on the contact area between the shunt and the metallic particles in the brush. The mechanical strength of the bond is decreased with a decrease in the percentage of the metallic particle component of the brush. While the method may be succesfully employed with brushes having a low percentage of metallic particles, if the percentage of metal is lower than 50 percent, it is usually impossible to obtain the mechanical strength necessary to satisfy the dictates of operational environmental conditions. Fortunately, applications requiring high bond strength also usually require a brush of high metallic content.
In those applications where it is desirable to provide increased contact area and at the same time to provide a brush having smooth sides, the embodiment shown in FIGURES 3 and 4 may advantageously be employed.
in FIGURES 3 and 4 there is shown a brush 22 molded from a mixture of powdered metallic particles and powdered graphite and having a slot 24 molded or cut in the face thereof. The shunt 26 is positioned within a slot with a brazing alloy, such as alloy preform 27, positioned between the shunt and the brush. The brush is then placed within the resistance heating unit and heating current passed between the electrodes 16 and 18 thereof to braze the shunt to the brush. In order to ensure contact of the upper electrode 18, the electrode is provided with an electrode tip 28 which will fit within the slot and contact the shunt over the peripheral surface thereof.
After passage of the heating current the brush will be brazed both to the bottom and the sides of the slot. The increase in the brazed contact area is advantageous in providing greater mechanical strength and increased electrical conductivity over the embodiment wherein the shunt is afiixed to the side of the brush. The additional metal provided by the brazing agent is effective in increasing the area of contact between the shunt and the metal particles of the brush to give the requisite mechanical strength and electrical conductivity at the bond. Although the intended application determines the minimum strength and the maximum conductivity tolerable, considerable flexibility in meeting the requirements is provided during brazing since control over both the brazing agent and the contact area is afiorded by this assembly method.
It will of course be noted that the position of the weld, the size of the shunt, and the shape of the slot will determine the shape of the welding tip used, Further, these factors will primarily be dictated by the application intended.
While the invention has been described with particular reference to brazing leads to metal-graphite brushes, it is applicable also to attaching leads to metal-graphite articles intended for other applications.
This invention may be variously modified and embodied within the scope of the subjoined claims.
What is claimed is:
1. The method of joining a shunt to a metal-graphite brush by heat supplied by current from electrode means which method consists of the steps of positioning the shunt adjacent to the brush with a brazing alloy in position to join confronting faces of the shunt and brush, holding the shunt, brush and brazing alloy with said confronting faces pressed together under substantial pressure, maintaining the pressure by force exerted by the electrode means and evenly distributed over the area of contact with the electrode means, then Connecting the shunt to the metal particles of the brush by electric resistance brazing produced by current passed through the brush, shunt and brazing alloy from said electrode means with the current and brazing time limited to prevent damage to the metal-graphite material, the additional metal provided by the brazing alloy being efiective in increasing the area of contact between the shunt and the metal particles of the brush.
2. A method in accordance with claim 1 in which said brush is composed of at least 50 percent copper.
3. A method in accordance with claim 1 in which said shunt is a copper shunt.
4. A combination in accordance with claim 1 in which said brazing alloy is a silver solder brazing alloy.
References Cited in the file of this patent UNITED STATES PATENTS 1,835,011 Burr Dec. 8, 1931 2,438,015 Lynn Mar. 16, 1948 2,507,780 Gilbert May 16, 1950 FOREIGN PATENTS 659,113 Great Britain Oct. 17, 1951-
Claims (1)
1. THE METHOD OF JOINING A SHUNT TO A METAL-GRAPHITE BRUSH BY HEAT SUPPLIED BY CURRENT FROM ELECTRODE MEANS WHICH METHOD CONSISTS OF THE STEPS OF POSITIONING THE SHUNT ADJACENT TO THE BRUSH WITH A BRAZING ALLOY IN POSITON TO JOIN CONFRONTING FACES OF THE SHUNT AND BRUSH, HOLDING THE SHUNT, BRUSH AND BRAZING ALLOY WITH SAID CONFRONTING FACES PRESSED TOGETHER UNDER SUBSTANTIAL PRESSURE, MAINTAINING THE PRESSURE BY FORCE EXERTED BY THE ELECTRODE MEANS AND EVENLY DISTRIBUTED OVER THE AREA OF CONTACT WITH THE ELECTRODE MEANS, THEN CONNECTING THE SHUNT TO THE METAL PARTICLES OF THE BRUSH BY ELECTRIC RESISTANCE BRAZING PRODUCED BY CURRENT PASSED THROUGH THE BRUSH, SHUNT AND BRAZING ALLOY FROM SAID ELECTRODE MEANS WITH THE CURRENT AND BRAZING TIME LIMITED TO PREVENT DAMAGE TO THE METAL-GRAPHITE MATERIAL, THE ADDITIONAL METAL PROVIDED BY THE BRAZING ALLOY BEING EFFECTIVE IN INCREASING THE AREA OF CONTACT BETWEEN THE SHUNT AND THE METAL PARTICLES OF THE BRUSH.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US852079A US3067318A (en) | 1959-11-10 | 1959-11-10 | Metal-graphite brush with brazed shunt |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US852079A US3067318A (en) | 1959-11-10 | 1959-11-10 | Metal-graphite brush with brazed shunt |
Publications (1)
Publication Number | Publication Date |
---|---|
US3067318A true US3067318A (en) | 1962-12-04 |
Family
ID=25312451
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US852079A Expired - Lifetime US3067318A (en) | 1959-11-10 | 1959-11-10 | Metal-graphite brush with brazed shunt |
Country Status (1)
Country | Link |
---|---|
US (1) | US3067318A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0107386A1 (en) * | 1982-09-30 | 1984-05-02 | Morganite Electrical Carbon Limited | Making connections to electrical brushes |
US20100038990A1 (en) * | 2008-08-18 | 2010-02-18 | Rui Feng Qin | Brush assembly for an electric motor |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1835011A (en) * | 1929-05-06 | 1931-12-08 | Boxill Bruel Carbon Company | Electrical contact element and process of making same |
US2438015A (en) * | 1945-01-10 | 1948-03-16 | Westinghouse Electric Corp | Shunted brush |
US2507780A (en) * | 1947-09-29 | 1950-05-16 | Bendix Aviat Corp | Method of attaching conductors to carbon brushes |
GB659113A (en) * | 1948-03-30 | 1951-10-17 | Stackpole Carbon Co | Improvements in or relating to carbon brush structures for use in dynamo electric machines |
-
1959
- 1959-11-10 US US852079A patent/US3067318A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1835011A (en) * | 1929-05-06 | 1931-12-08 | Boxill Bruel Carbon Company | Electrical contact element and process of making same |
US2438015A (en) * | 1945-01-10 | 1948-03-16 | Westinghouse Electric Corp | Shunted brush |
US2507780A (en) * | 1947-09-29 | 1950-05-16 | Bendix Aviat Corp | Method of attaching conductors to carbon brushes |
GB659113A (en) * | 1948-03-30 | 1951-10-17 | Stackpole Carbon Co | Improvements in or relating to carbon brush structures for use in dynamo electric machines |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0107386A1 (en) * | 1982-09-30 | 1984-05-02 | Morganite Electrical Carbon Limited | Making connections to electrical brushes |
US20100038990A1 (en) * | 2008-08-18 | 2010-02-18 | Rui Feng Qin | Brush assembly for an electric motor |
US8154169B2 (en) * | 2008-08-18 | 2012-04-10 | Johnson Electric S.A. | Rail brush assembly with detent |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2759161A (en) | Electrical connector and method | |
US2888742A (en) | Compound metal member | |
CN107743429B (en) | Method for connecting a conductor to a terminal element and terminal assembly produced thereby | |
JP2020522872A (en) | Joint of copper terminal and aluminum conductor and plasma welding method thereof | |
US2655641A (en) | Electrical connector having a mercury amalgam coating on its inner surface | |
US2427727A (en) | Leading-in wire | |
US4902867A (en) | Method of joining an insulated wire to a conductive terminal | |
US3067319A (en) | Metal-graphite brush with welded shunt | |
US3078562A (en) | Method for attaching silver-cadmium oxide bodies to a supporting member | |
US3067318A (en) | Metal-graphite brush with brazed shunt | |
US3648014A (en) | Method of joining copper braid to aluminum and the joint formed thereby | |
US11936152B2 (en) | Production of a planar connection between an electrical conductor and a contact piece | |
US2390890A (en) | Method of soldering | |
US2509020A (en) | Electrical contact member and method of making the same | |
US3519778A (en) | Method and apparatus for joining electrical conductors | |
US1908859A (en) | Leading in conductor | |
JP3815089B2 (en) | Fuse-free circuit breaker lead wire, manufacturing method thereof, and fuse-free circuit breaker | |
WO2021047307A1 (en) | Spot welding method for multi-layer conductor of motor winding | |
US2509021A (en) | Electrical contact member and method of making the same | |
JP2644860B2 (en) | Crimp terminal | |
CN109788643B (en) | Aluminum-based solderable contact | |
US3795786A (en) | Method of tungsten inert gas welding electronic components and burning away contaminants | |
JPH0982377A (en) | Electric wire connecting method | |
US4417119A (en) | Liquid joint process | |
JP4235353B2 (en) | Lead wire and terminal joining method |