US3028515A - Brush holder - Google Patents

Description

April 3, 1962 R. A. CHEETHAM 3,028,515

BRUSH HOLDER Filed Oct. 27, 1958 2 sheets sheet 1 kg 24 4s 46 g 2 2 32 =2 so Fig.2

INVENTOR.

Roben A. Cheer/ram His: Attorney April 3, 1962 R. A. CHEETHAM BRUSH HOLDER 2 Sheets-Sheet 2 Filed Oct. 27, 1958 m? wwJ 8H J F if QE E W E K QWS 6 86 1@ lG 0m m mm m mm mm mm m INVENTOR. Robert A. Cheer/7am His Afforryey United States Patent "ice 3,028,515 BRUSH HOLDER Robert A. Cheetham, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Oct. 27, 1958, Ser. No. 769,766 2 Claims. (Cl. 310-247) This invention relates to brush rigging for dynamoelectric machines and more particularly to a brush holder that is formed from a single piece of sheet metal.

In the past, it has been common practice to form brush holders by welding, riveting, or otherwise securing sheet metal parts together in the form of a brush holder. Although these brush holders have operated satisfactorily, they have disadvantages in that the welded or riveted joint must be made with care so as to avoid failure during use and are more costly as compared to the brushholder of this invention because of the extra assembly steps required.

It is accordingly, an object of this invention to provide a brush holder that is formed from a single piece of sheet metal. The brush holder preferably includes a pair of U-shaped members which are integral with a base member and which form a brushholding chamber. By the use of a pair of U-shaped members extending from a base member, the cost of fabrication of the brush holder is greatly reduced and the brushholder has inherent resiliency so as to provide a simple and eifective method of slidably supporting a brush.

Another object of this invention is to provide a brush holder that is formed with ventilating openings for permitting air to pass in contact with the brush and wherein at least one of these openings receives a lead Wire that is connected with the brush.

Still another object of this invention is to provide a brush holder which is formed to achieve line contact between the brush holder and brush whereby the brush is firmly gripped for sliding movement without binding.

Another object of this invention is to provide a continuous method for forming brush holders from a length of sheet metal.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a plan view with parts broken away of a dynamoelectric machine that is fitted with a brush holder of this invention.

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1.

FIGURE 3 is a perspective view'of the brush holder of this invention showing its relationship with the spring and brush that fit Within the brush holder.

FIGURE 4 is a plan view illustrating the steps of fabrication of a brush holder made in accordance with this invention. I

FIGURE 5 is a sectional view of apparatus for shaping the length of sheet metal illustrated in FIGURE 4.

Referring now to the drawings and more particularly to FIGURE 1, a dynamoelectric machine generally designated by reference numeral has a main frame 12 connected with end frames 14 and 16 by one or more through bolts 18. The dynamoelectric machine may be of any conventional design that includes acommutator 20 supported by a shaft that is journalled for rotation, in the end frames 14 and 16. The shaft carries the usual armature which rotates within the usual field winding. This particular brush holder is adapted for use with any type of dynamoelectric machine and the particular con- 3,028,515 Patented Apr. 3, 1962 struction of the dynamoelectric machine therefore forms no part of this invention. The brush holder has particular utility, however, in machines that have an annular main frame as the brush holder is attached directly to the annular frame. The dynamoelectric machine has an annular frame 12 to which is attached the brush holder of this invention. The brush holder in FIGURE 1 is generally designated by reference numeral 22 and is secured to the annular frame 12by means of a fastener 34 which in this case is a rivet. The brush holder is insulated from the frame by insulating material 26 and 28 as is better shown in FIGURE 2. The brush holder contains a brush of any well known construction 30 which slides within the brush holder and which is spring biased against the commutator by a spring 32. One end of the spring encircles the head 34 of the rivet and the rivet head thus serves to position the spring within the brush holder. The brush holder of this invention is formed from a single piece of sheet metal material. The brush holder as is best illustrated in FIGURE 3 has an arcuately extending base portion 24 which is adapted to fit the annular main frame of the dynamoelectric machine. The base portion 24 has an aperture 36 which receives the fastener 34 when the brush holder is being secured to the annular frame of the dynamoelectric machine. EX- tending radially from the arcuately extending base portion 24 are a pair of U-shaped members 38 and 40 as is best illustrated in FIGURE 3. Each U-shaped member has an outwardly flared edge 42 and has an arcuately extending web portion 44. The lower edges of the U-shaped members are spaced from the base member 24 to provide ventilating passages designated by reference numeral 4-6.

The U-shaped members have their open ends facing one another to form ventilating passages 48, one of which also serves to receive the lead wire 50 of the brush. The lead wire will of course be connected with either the field winding of the dynamoelectric machine or directly to the frame, depending upon whether the brush is insulated from the frame or Whether it is connected directly to the frame. The connection of the brush to the dynamoelectric machine will of course vary with the type of machine with which the brush holder is being used.

It will be apparent from an inspection of FIGURE 3 that the brush holder 22 provides for a firm gripping of the brush 30 when it is inserted within the brush holder. Thus, the arcuate portions 44 of the brush holder serve to effect a line contact with the edges of the brush while the side walls 52 of the U-shaped members operate to engage the side faces of the brush without causing binding. The inherent resiliency of the brush-holder due to its formation from a single piece of sheet metal also operates to provide a brush holder that engages the brush without any binding as the brush holder is free to give in certain directions. Thus the Ushaped members are free to move away from one another a small amount due to the inherent resiliency of the brush holder and also the side walls 52 are free to'move away from one another due to the inherent resiliency of the sheet metal brush holder.

In FIGURES 4 and 5 a preferred method for forming the brush holder 22 is shown. The apparatus for forming the brush holder includes a plate member 60 which may be reciprocated by a punch press or the like not shown and a die holding member 62. The member 60 carries punches 64, 66, 68, 7t} and 72 which operate to form various operations on a length of sheet metal designated by reference numeral 74. The die holder supports dies 76, 78 83 and 8-5. The sheet metal member 74 is fed between members 60 and 62 by a suitable feeder mechanism not shown that preferably operates in' synchronism with the punch press or other device that reciprocates plate 6%. As the sheet metal piece 74 is fed between the plates dti'and 62, several shaping and forming operations are performed on the length of sheet metal. The first operation performed starting at the right hand side of the FIGURE is the punching out of apertures 36. These apertures are punched out by the punch member 64. Simultaneously with the punching out of apertures 36, the apertures 84} are formed by suitable punches not shown. The apertures 82 are also simultaneously formed-bysuitable punches not shown during the time that the apertures 36 are formed. As the material 74 moves through the punch press, a pair of tools '66 operate to form the apertures 84; When apertures 80 and 84 have been formed, the-sheetmetal has a generally cross-shape provided by sections 86 and sections 37 and 3?. Following the formation of apertures 8 the sections 86 are placed between die members 76 and punch 68 to form the outwardly flared portion 420i the'brush I holder and to also form the arcuately extending web portion 44; Foiiowing this operation the sections 86 are fed between punch 7t) and dies 78'and- 83 to fornr ly to their final position by upward extensions of die member 83 not shown which have an outer configuration that corresponds to the outer configuration of the U- shaped members after they have'been pressed betweenpunch 70 and die members 78 and 83.- These two upward extensions thus force the U-shaped members toward one another during the ,time'that the tool'or punch 70 is being forced downwardly. The" final end product is'illustrated in FIGURE 3 of the drawings and has been fully described j hereinbefore'.

It will be appreciated that the method for forming these brush holders is continuous as the material is con- 'tinuously fed between plates 68 and 6 2. The plate constantly reciprocates to simultaneously perform all the operations described above once the material has been :fed entirely through the punch press.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A brush holder for a dynamoelectric machine formed from a single piece of sheet metal oomprising, an arouately extending base portion, a pair of spaced U- shaped members integral with and extending from said base portion and facing each other to form a brush holding chamber, each U shaped member having a pair of'side walls joined'by an arcuately extending web, said side walls terminatingin an outwardly flared edge and having ends located adjacent to and spaced from said arcuately extending base portion.

2. In combination with a dynamoelectric machine having an annular frame and a commutator, a brush holder 7 having an arcuately extending base'portion secured, to said frame,-a pair ofspaced U-shaped members integralwith and extending from said base portion and facing each" other to form a rectangular-shapedbrush holding'chamber, each U-shaped member being defined'by a pair of side walls that are joined by an arcuately extending web, a brush slidable in said brush holding chamber having end walls that are in line contact with said arcuately 6X' tending webs, and a spring interposed between said arcu-' ately extending base portion and said brush for urging said brush into engagement with said commutator.

References Cited in the file of this patent UNITED STATES PATENTS 1,101,814 Sammarone June 30, 1914 1,519,222 Seiss Dec. 16, 1924 2,825,831 Franck Mar. 4, 1958 2,870,354 Antonidis Jan. 20, 19 59 FOREIGN PATENTS v 243,204 Switzerland Dec. 2, 1946'

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