US1147451A - Pigtail connection. - Google Patents

Description

W. SHAW.

PIGTAIL CONNECTION.

APPLICATJQN FILED OCT. 15, 1912.

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WITNESSES IJNVENTOB ATTORNEY sTA'rEs rrnnr on ICE.

WILLIAM SHAW, OF LAKEWOOD, OHIO, ASSIGNOR TO CARBON COMPANY, OF

' CLEVELAND, OHIO, A CORPORATION OF OHIO.

PIGTAIL CONNECTION.

Specification of Letters Latent.

Patented July 20, 1915.

Application filed October 15, 1912. Serial No. 725,850.

clear and exact description.

This invention relates to connections for brushes on dynamo-electric machines commonly called pigtail connections.

the invention is to secure One object of h the brush with minimum the conductor to contact resistance.

Another object is to secure the conductor to the brush so that it cannot work loose in practice, but to attach it in such a manner that it can be readily removed, and attached to another brush when. the first one is no longer serviceable;

Other objects will appear in the appended description.

In the drawings: Figure 1 is a section of a-spun tube from which clips are made. Fig. 2 is a View of the clipatter the pigtail has been inserted in the tube shown in Fig. 1 and compressed. Fig. 3 is a. top view of the connection shown in Fig. 2. Fig. 4 is a modified form ot clip. Fig. 5 is a View of a brush before the pigtail is attached. Fig. 6 is a view of the brush with the clip shown in Fig. 3 attached thereto. Fig. 7 is a view of a brush with the clip shown in Fig. i attached thereto. Fig. 8 is a section on the plane AA of Fig. i}. Fig. 9 is a view of a modified form of brush before the pigtail'is connected thereto. Fig. 10 is a view of the brush shown in Fig. 9 with the pigtail attached. Fig. 11 is a section taken on the line BB of Fig. 10. Fig. 12 is a View of the nut used to clamp the pigtail in Fig. 10. Fig. 13 is a modified form of connection. Fig. 14 is a section of a slightly different form.

Referring to Fig. 1, if a section of a tube 1 be spun down at one end as at 2, a conductor inserted through the reduced opening, and the tube. pressed together, an attractive and serviceable clip results. A side view of the clip and pigtail is shown in Fig. 2. A hole 3] is formed through the clip, Fig. 3, and the same is threaded to receive-a screw. The method of making this new form of clip is described in my application filed Aug. (3, 1912, Serial No. 713,571, and hence the manner in which it is made is given in this application only in a brief way. This form of clip is easily made and gives a very attractive strong connection. It might seem that if a hole were threaded through such a clip that it would not be strong enough to serve as a nut to clamp the connection to the brush, but it has been found that the clip will serve as a nut and makes a strong connection. The small wires of the pigtail which are compressed between the sides seem to be rigidly held inplace so that they help form the threads.

A brush 4, Fig. 5, has a hole 5 formed through it and a channel or slot 6 is formed shown. This channel is cut to such a depth that the clip placed in it is approximately flush or beneath the surface of the brush; so as to prevent the connection from interfering with the movement of the brush in the holder. The clip 5 with the attached conductor is placed in the slot 6, Fig. 8, and drawn firmly against the brush by the screw (3. The screw may be locked in place if desired by the bail 7 which tits in the slot in the screw head. The lock may in some cases be omitted. The slot (3 need not necessarily extend to the top of the brush parallel o. its sides. It may extend diagonally toward the top corner of the brush.

In some types of brushes a separate metallic piece is extended over the top of the brush to serve as a rest for the spring hammer that forces the brush against the commutator. My new form of clip can be made to serve both as the nut and as the hammer rest bymaking it of suitable length and bent to extend part way or entirely across the top oi the brush. Such a clip is shown in Fig. 4 and shown connected to the brush in Fig. 7. This arrangement gives additional contact surface as the top portion 8 of the clip engages the top of the brush. In this form, as well as that shown in Fig. (3, the shape of the clip is non-circular so that it cannot work loose. The bail 7 serves to prevent the screw from turning so that the connection is securely locked. WVhen the brush is worn'out the bail may be pulled out or the brush may be broken apart. The screw can then be disengaged from the nut and the connection placed on another brush.

In Figs. 9, 10 and 11, I have shown a modified form of connection. The pigtail end in this case is not secured to a clip, but

is coiled around the screw 6 in a groove and tightly compressed therein by an angular shaped nut 10. The nut extends over the top of the brush and serves as ahammer support and furnishes additional contact surface to take the current from the brush. .The prolongation of the nut also serves to eil'ectively prevent the nut from turning. The pigtail may extend through the groove or it may extend up through a straight slotted brush as in Fig. 5, and pass through a hole or notch 12 in the nut extension as in Fig. 13.

If desired the groove 9 may be omitted and the igtail clamped by the nut 10 against the flat bottoin of the slot as in Fig. 14. I prefer, however, the arrangement shown in Fig. 9 asthe wires 1-3 are compressed in the groove 9 and give elasticity to the connection such that an expansion of the screw or other loosening will not destroy the good contact. This grooveiis preferably convergent as shown, though'on'e side need not necessarily be vertical. The elastic eibe limited to any form of pigtail, but is intended to include all forms of flexible conf v ductors.

Having described my invention What I claim is:

1. In a current collector, a brush having a and such'coatscrew from turning.

hole therethrough terminating ma channel,

said channel extending .toth'e top of the brush, a nut inthe channel. and a screw in said-hole'engaging thetnut, said nut having a prolongation extending; over the top of the brush, and a igtail fastened to the prolongation. I

i 2. In a currentcollector, a brush having a hole therethrough, a nut having a prolongation extending over the top of the brush, a screw in said hole engaging the nut and a igtail fastened to the prolongation.

3. In a current collector, a brush having a channel in one side, a current connection consisting of a clip. compressed around a stranded conductor, said connection having a hole therethrough with threads cut in the clip and strands of said conductor, a screw extending through the brush and,sec'uredin said threaded hole to retain the clip in the channel.

'4. In a current collector, a brush having a channel in one side, a current connection consisting of a clip compressed around a stranded conductor, said connection having a hole therethrough with. threads cut in the clip and" strands oi said conductor, a screw extending, through the brush and secured in the threaded hole to clamp the clip in said channel, d a. bail in the slot of thescrew head ext K into the brushto greventthc In testimony Wl'lQIQOf I have hereunto sig ed my name. WILIJAM snA-w'. Witnesses r E. M. SPELMAEY, L. 0. B12007

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