US2509021A

US2509021A - Electrical contact member and method of making the same

Info

Publication number: US2509021A
Application number: US696551A
Authority: US
Inventors: Joseph F Settle
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1946-09-12
Filing date: 1946-09-12
Publication date: 1950-05-23
Anticipated expiration: 1967-05-23

Description

May 23, 1950 J. F. sE'rrLE ELECTRICAL CONTACT MEMBER AND OF MAKING THE SAME ed Sept. 12, 1946 HEW. a

METHOD Inventor Joseph E Settle,

b5 His Attorney.

Patented May 23, 1950 ELECTRICAL CONTACT MEMBER AND METHOD OF MAKING THE SAME Joseph F. Settle, Schenectady, N. Y., asslgnor to General Electric Company, a corporation 01' New York Application September 12, 1946, Serial No. 696,551

1 Claim. 1

My invention relates to electrical contact members and to an improved method of making the same.

An object of my invention is to provide an improved electrical member.

Another object of my invention is to provide an improved method of making an electrical contact member.

A further object of my invention is to provide an improved electrical contact brush member having a carbonaceous material porton and an. arrangement for securing a terminal clip member thereto.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize mv invention will be pointed out with particularity in the claim annexed to and forming a part of this specification.

In the drawing, Fig. 1 is a sectional side elevational view of a part of an electrical contact member formed as a brush for electrical rotating machinery provided with an embodiment of my invention; and Fig. 2 is a sectional side elevational view of a part of the arrangement shown in Fig. 1 prior to the final assembly thereof.

Referring to the drawing, I have shown my invention in connection with an electrical contact member formed as a brush adapted to be used to make a connection between a stationary conductor and a rotating electrical device. This contact brush member is shown as having a portion I made of carbonaceous material, such as graphite or a mixture of graphite and metal powders, or of similar materials, as are conventionally used for such members, and an arrangement is provided for forming a good electrical contact between the contact brush member and a stationary terminal through a flexible electrical conductor 2 which is welded, brazed, or otherwise suitably secured to a terminal clip member 3 of any suitable material, such as steel, arranged over an end and in contact with a surface of the carbonaceous material brush portion I. In order to provide a secure connection between the terminal clip member 3 and the carbonaceous material brush portion I, a passage 4 is preformed in the carbonaceous material brush portion I and a. passage 5 is similarly preformed in the contact clip member 3. The terminal clip member is then arranged over an end of the carbonaceous material brush portion with the two passages 4 and 5 substantially in coaxial correspondence, as

shown in Fig. 2, and then a two-part rivet is arranged in the passages 4 and 5 with stem portions 6 and I of the two parts of the rivet extending through the members I and 3 in the openings 4 and 5 with heads 8 and 9 of the rivet part in engagement with the opposite outer side of the carbonaceous material brush portion and the terminal clip member. When these parts are thus assembled, the two parts of the rivet are adapted to be welded together by the passage of an electric current therethrough, such that the inner adjacent ends l0 and I I of the two rivet parts are welded together by the passage of current therethrough to provide a rigid unitary rivet securing together the terminal member and the carbonaceous material brush portion I. When the rivet cools, the contraction thereof assists in providing a still firmer connection between the terminal clip member 3 and the brush member portion I. This mechanical connection may be further strengthened, and the electrical resistance of the contact between the terminal clip member 3 and the carbonaceous material brush member portion I may be reduced by providing a bonded coating II of low electrical resistance metal, such as copper, on the surface of the carbonaceous material brush member portion 9 adapted to be arranged in contact with the terminal clip member 3 and applying an adherent coating of an alloying metal, such as tin or zinc, over the surface of the clip member 3 prior to assembly. These two alloying metals are adapted to be alloyed together to provide a low resistance bond between the metal of the clip 3 and the carbonaceous material portion I of the brush member by the heat generated by the passage of current through the two parts of the rivet during the welding thereof and by the passage of current through the carbonaceous material brush portion I and the clip member during this rivet-welding operation. This alloying of the two contact metals is facilitated by the application of a non-corrosive flux, such as a mixture of rosin and alcohol, over the surface 01' the alloying metal and particularly over the surface of the copper coating in order to remove the oxide from the engaging surfaces of the alloying metals and to facilitate thereby the wetting of these adjacent surfaces when the metals become molten. This provides a good electrical and mechanical bond between the terminal'clip member 3 and the carbonaceous material brush member portion I by the secure unitary riveted construction of the two-part welded rivet and by the continuous good electrical contact between the steel clip 3, the tin surface thereon, the alloy of the tin and copper, the copper surface, and the carbonaceous material I, forming a. good steel-totin-to-alioy-to-copper-to-carbonaceous material electrical conductor oi relatively low resistance reinforced by the rivet which extends therebetween where these or other suitable electrically conductive members are used in making these parts.

While I have illustrated a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claim to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

An electrical contact brush having a carbonaceous material portion and a metal terminal clip 20 member adapted to be arranged in contact with a surface of said carbonaceous material portion, said carbonaceous material portion having a coating of copper on the surface thereof adapted to be arranged adjacent said clip member and said 4 metal clip member having a coating of tin on the face thereoi arranged to be adjacent said carbonaceous material portion, a two-part rivet extending through both said terminal clip member and said carbonaceous material portion with a head on the outer end of each of said rivet parts and with the adJacent inner ends of said two rivet parts welded together to form a unitary rivet for securing together said terminal clip member and said carbonaceous material brush portion with the heat of said weld forming an alloy between said tin and said copper coatings.

JOSEPH I". SEI'ILE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 661,669 Rohrer Nov, 13, 1900 1,210,029 Auel Dec. 28, 1916 2,242,014 Martin May 13, 1941 2,436,852 Carmichael et al. Mar. 2, 1948