US2104721A - Brush holder assembly and brush - Google Patents

Description

Jan. l1, 1938. c. E. BERGER BRUSH HOLDER ASSEMBLY AND BRUSH Filed March 3l, 1936 CLARE Patented jan. l1, 1938 UNITED STATES PATENT OFFICE BRUSH HOLDER ASSEMBLY AND BRUSH Application March 31, 1936, Serial No. 71,958

7 Claims.

This invention relates to brushes and brush holders for generators and particularly for homopolar generators.

It is an object of this invention to provide a brush and means of support therefor, whereby to support the brush in such a manner that it will follow the contour of the commutator or slip ring, with which used, irrespective of eccentricity existing in the commutator or slip ring.

't is a further object of this invention to provide in such mechanism, means whereby the brush is supported for slight rocking movement about a guiding pin whereby the brush face remains in close contact with the commutator or slip ring at all times, irrespective of irregularity in eccentricity of the surface of the commutator or slip ring with respect to the axis of rotation thereof.

It is further object of this invention to provide such a brush and brush holder as will carry a greater amount of current, without sparking, than a brush of the Same size and composition, mounted in a conventional brush holder.

It is a further object of this invention to provide means for supporting a brush for contact with the surface of a commutator or slip ring in such manner as to apply resilient force at two spaced points on the brush, which are widely separated from guiding means adapted to retain the brush in position while allowing limited movement thereof toward and from the commutator or slip ring surface and limited rocking movement thereof with respect to the guiding means.

These and other advantages will appear from the following description taken in connection with the drawing.

In the drawing:

Figure l is an end elevational View of a brush and brush holder assembly, according to my invention;

Figure 2 is a plan View of the same.

Referring to the drawing in detail, the brush holder comprises a frame having a rectangular portion I with a rectangular aperture 2 therein and outwardly extending pintle arms 3 arranged in parallelism at opposite sides thereof. Extending from end to end of the frame and arranged centrally within the aperture 2 is a guiding pin 4 which is secured at opposite ends in the frame. Secured in apertures at the outer ends of the arms 3 at each side of the frame is a pintle 6 which is removably secured in the apertures of the arms 3 by means of cotters 1 or any other suitable means.

As shown in Figure 2, four arms 3 are arranged at each side of the frame, but it is, of course, to be understood that any number of such arms may be used depending upon the number of brushes to be supported in the brush holder. Rotatably secured between each pair of arms 3 to pivot on the pintle 6 is a brush arm 8 which has a central portion arranged concentrically with the axis of the pintle 6 and an annular flange 9 at one side thereof, which flange is equipped with notches Ill. Also mounted in like manner on the pintle 6 between each pair of arms is a thrust washer II. A coil spring I2 is disposed between each brush arm and the adjacent thrust washer and has one end thereof formed into a loop I3 which is adapted to be hooked about the lower edge of one pintle arm 3. The other end thereof has a straight handle portion I4 formed thereon, which is adapted to be selectively received in one of the slots Ill in the annular iiange 9 of the brush arm.

As shown in the drawing, the righthand springs I2, when so disposed, urge the righthand brush arms 8 in a counterclockwise direction about the righthand pintle 6. The lefthand brush arms 8 are supported in the same manner for rotation about the lefthand pintle 6 and are adapted to be swung in a clockwise direction about the pintle by means of the left hand springs I2. Adapted to be supported within the rectangular aperture 2 are three brushes I5 of rectangular cross section, each of which has a longitudinally disposed slot I6 therein and which extends from the lower face I1 thereof throughout a part of the length and which slot I6 is adapted to receive the above described pin 4. The extreme ends of the brush arms 8 are adapted to contact the top surface of the brush I5, which surface is preferably flat. The cross sectional area of the respective brushes is less than the corresponding portion of the aperture 2, whereby the brushes I5are adapted to be supported for slight pivotal movement about the pin 4 in the aperture 2. The points of contact of the extreme ends of the brush arms 8 with the top surface of the respective brushes I5 are spaced apart a substantial distance and the extreme ends of the brush arms 8 are preferably of arcuate contour, as shown in the drawing, in order to produce substantial line contact of the arms with respect to the top faces of the brushes whereby to facilitate the rocking movement thereof. This rocking movement is resisted by the springs I2 which resiliently urge the respective brush arms 8 against the top face of the brush. The lower face I1 of the brush I5 1s preferably arcuate and of a contour which is complementary to the surface of the slip ring or commutator I8. The frame portion I has an upstanding bracket I9 at the rear end thereof, which is slotted at 2|] to provide means for attachment of the frame to the generator.

As will be clear from the drawing, the eifective tension of the springs I2 may be selectively adjusted by engaging the portion I4 of each with desired slots ID in the annular flange 9. Bv this means, wear may be compensated for by increasing the eiective tension of the springs and necessarily the position of the respective brush arms with respect to the frame for a given eiective spring tension. Thus, where the desired effective spring tension for a new brush is that shown in Figure l and the length of the "ish being also that shown in that gure, upon `lly reduce the effective spring tension, the portion ffl of the respective springs may be moved over into the second notch, whereby to compensate for the wear in the brush.

While I have shown an assembly including mounting means for three brushes, it is, of course, to be understood that the number of brushes used depends upon the commutator surface and that the drawing is, in this respect, illustrative only and that I desire to comprehend within my invention the use of a single brush or any number thereof.

it is further to be understood that the springs for resiliently swinging the arms 8 about the pintles may be replaced by other known resilient means such as known pneumatic and hydraulic devices or tension or compression springs for performing the same function.

Furthermore, the arms 8 may be dispensed with and adjustable helical flat springs having their ends provided with surfaces adapted to Contact the brush in the same manner as do the ends of fhe arms 3 may be substituted for the springs and arms as illustrated and described above.

t will be understood that the above described structure is merely illustrative and that I desire to comprehend within my invention such modications as come Within the scope of the claims and the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

l. In a brush assembly for a generator having a commutator, a brush, means to support said brush for relative sliding and rocking movement with respect to a predetermined axis parallel to the axis of said commutator, and resilient means ior engaging said brush at opposite sides of said predetermined axis and urging said brush toward said commutator.

2. In a brush assembly for a generator having a slip ring, a brush, means to support said brush' for sliding and rocking movement relative to a fixed axis parallel to the axis of the slip ring, and means for applying resilient pressure to said brush at spaced points at opposite sides of said iixed axis to urge said brush resiliently toward said slip ring and resiliently resist rocking movement thereof.

3. A brush assembly for a generator having a commutator comprising a brush supporting frame adapted to be secured to said generator adjacent said commutator, brush guide means in said frame including a guide pin parallel to the axis of said commutator, a brush having a longitudinal slot adapted to rockably and slidably engage said brush guide pin, and means on said frame for applying resilient pressure at spaced points on said brush at opposite sides of said slot to urge said brush toward said commutator.

4. A brush assembly for a generator having a slip ring comprising a brush supporting frame adapted to be secured to said generator adjacent said slip ring, brush guide means in said frame including a guide pin parallel to the axis of said slip ring, a brush having means adapted to rockably and slidably engage said brush guide pin, and means on said frame for applying resilient pressure at spaced points on said brush at opposite sides of said guide pin to urge said brush toward said slip ring and resiliently resist rocking movement thereof about said pin, said last named means being adjustable to compensate for wear of said brush.

5. In combination, a brush having a slotted face, a holder for said brush comprising means for yieldingly urging the brush against the commutator and a transverse pin disposed parallel to the axis of the commutator arranged Within the slot in the brush about which pin the brush is adapted to rock, said yielding means being adapted to engage said brush at points thereof disposed at opposite sides of said slot.

6. In combination, a transverse pin in a brush holder, a. slotted brush loosely mounted on said pin, said pin being located adjacent the open end of said slot, and yielding means engaging said brush at opposite sides of said pin for maintaining said brush on the pin against the commutator, said pin being substantially parallel to the axis of said commutator.

7. In combination, with a commutator, of a brush having a commutator engaging face with a slot opening into said face disposed radially of said commutator and axially thereof, means mounted within said slot adapted to permit of a rocking movement of said brush without movement with the commutator and yielding means for impelling said brush against said commutator as guided by said means upon which it rocks.

CLARENCE E. BERGER.

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