US969796A - Brush for dynamo-electric machines. - Google Patents

Description

E. T. MUG. BRUSH FOR DYNAMO'ELEGTRIU MAOHI APPLICATION FILED SEPT.19,1904.

Patented Sept. 13, 1910 7108.72 for:

Fezzo and A it own perienced in e EDWARD r. MUG,

OF NORWOOD, OHIO, ASSIGNOB, TO THE BULLOCK ELECTRIC MANU- FACTURING OOMPA NY, A CORPORATION OF OHIO.

BRUSH FOR DYNAMO-ELECTRIC MACHINES.

Specificationof Letters Patent. Patent ds h 13 1910 Application filed September 19, 1904. Serial No. 225,064.

To all whom 'it'may concern:

Be it known that I, EDWARD T. MUG, citizen of the United States, residing at Nor- Wood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Brushes for Dynamo- Electric Machines, of which the "following is a full, clear, and exact specification.

.My present invention relates to brushes for dynamo-electric machines and to the method of connecting conductors made of flexible material to carbon brushes.

Heretofore reat difficulty has been execting a good electrical and mechanical connection between the highresistance carbon 'brush ordinarily employed in dynamo-electric machines and the low resistance braided flexible conductor or pig tail connected thereto.

The flexible con-- ductor has been connected to the carbon brush in a great many ways, for instance, by

soldering it directly to the copper plated surface of the brush, by soldering it. in a slot formed in the brush, by fastening it to abolt' placed in a transverse hole drilled through said brush, by clamping and solderlng it to a metall c clip, which is then in turn soldered to the copper plating of the brush, etc. soldered connections are objection'able on account of the gliability of the solder melting and the connection between the conductor and brush becoming loosened,

if not entirely separated, if the brush should become overheated When carrying an ex- CBSSIVB. amount of current. The other methods above enumerated are objectionable in that they require a multiplicity of parts which are expensive to construct and as semble. V

The object of my invention is to improve the method of attaching to the carbon .brush the flexible braided Wire conductor or cable commonly, employed to carry the current transmitted to or from said brush, so as to enable said brush to carry without undue heating the full current transmitted thereto or therefrom.

The invention aims to reduce the cost of the brush and attached pig tail, and to produce a reliable article of manufacture which will not be subjected to the objections which-have been raised against the older forms of. brushes. To this end I form the brush so that one end of the flexible conductor, or pig tail is embedded in the body of the brush and is preferably flared out so as to bring the individual wires composing the conductor into intimate contact with the material of which the carbon brush is made. The method of connecting the flexible conductor to the brush which 1 prefer to employ is to embed one end of said conductor in the material of which the brush is made when said material is in a plastic. semi-plastic, or pulverulent conditiom and thenmold the brush into the desired shape.

In the accompanying drawing, which illustrates the preferred embodiment of my invention, Figure 1 is a perspective view of a'carbon brush with the flexible pig tail attached thereto in accordance with my invention, the said "pigtail entering the brush through an opening in its upper end; Fig. 2 is a vertical sectional view of the brush shown in Fig. 1; Fig. 3 is a section on the line 3 B of Fig. 2; and Fig. 4 is a perspective view of a modified form of my invention illustrating the flexible lead or.

pig tail entering the carbon brush through an opening in its side.

Referring now to Figs. 1, 9, and 3, A represents the block of carbon forming the brush proper. Embedded in the material of which said carbon block is made,pret'erably when said material is in a plastic, semiplastic, or pulverulent condition in a mold is the flared end of a flexible braided wire conductor or pig tail B, the separate strands of said flared end being indicated in dotted lines Fig. 2 at C. A bundle of unbraided wires may be used if so desired. It will be noted by reference to Figs. 1 and 2 that the end of the flexible conductor B which is embedded in the carbon block enters said block an appreciable distance before it is unraveled or flared out. This is indicated clearly at D. As shown in Fig. 3

the strands of the flared end of the flexible in the side of the brush, as it often happens that such a brush is employed in a brush holder, which has a spring finger bearing on the top surface of the brush, and by bringing the flexible connection out through the side of the brush all interference with such finger is obviated. The flexible leadB is preferably provided with a terminal clip at its opposite end, said clip being indicated in Fig. 1 by F.

Such a brush as just described may be employed to carry much heavier currents than the ordinary carbon brush with the pig tail soldered, or otherwise fastened thereto, and it will be readily seen that a very in timate connection, electrically and mechanically speaking, is made between the parts of the carbon brush and the flexible c011- ductor.

It is seen that in a brush constructed according to my invention no hole or channel need be drilled into or through the brush for the reception of holding screws or solder. In fact, the four sides of the brush are entirely uninterrupted or unbroken except in the modification shown in Fig. 4, in which the flexible conductor emerges from the brush at the side near the top.

Although I have illustrated the preferred embodiment of my invention, I do not care to be limited thereto, as various changes may be made without departing from the spirit. and scope of my inyention, and I aim in the appended claims to cover all such changes.

Having thus described my invention, what I claim as new and desire to cover by Letters Patent is r 1. A carbon brush, and a flexible conductor composed of a plurality of strands having the strands at one end separated one from another and embedded in said brush.

2. A carbon brush, and a flexible conductor composed of a plurality of wires, one

BGEJQB end of said conductor being flared and embedded in said brush.

3. A carbon brush, and a flexible braided wire conductor having one end unraveled and embedded in said-brush."

4;. A carbon brush, and a flexible braided wire conductor having one end unraveled and embedded in said brush said conductor entering saidbrush an appreciable distance in its braided condition.

. 5. A carbon brush, and a flexible conductor composed of a plurality of wires in a compact bundle, one end of said conductor being spread out through the body of said carbon brush.

6. A carbon brush, and a flexible conductor composed of a plurality of wires in a compact bundle, one end of said conductor being spread out through the body of said carbon brush, said conductor entering said carbon brushan appreciable distance in its compact form.

-7. The method of connecting a flexible conductor with a carbon brush which consists in embedding the flared or unraveled end of said conductor in the material of which the brush is made when said material is in a plastic, semi-plastic or pulverulent condition, and then molding the brush into the desired shape.

8. A carbon brush, a flexible conductor composed of a plurality of wires in a compact bundle, one end of said conductor being spread out through the body of said brush,

'saidbrush having unbroken or uninter- In .testimony whereof I a-flix my signature,

in the presence of two witnesses. v

. EDWARD T. MUG. Witnesses:

B. A. BEHREND, FRED J. KINSEY.

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