US1923864A - Brush plate assembly - Google Patents

Description

Aug. 22, 1933. H J H M ET AL BRUSH PLATE ASSEMBLY Filed Dec. 27, 1930- 5 Sheets-Sheet l Mentor HERBERT J. GRAHAM LEWIS A. DARLING 1933- I H. J. GRAHAM El AL 1,923,864

BRUSH PLATE AS SSSS LY Filed Dec. 27, 1930 3 Sheets-Sheet 2 lhdentor HERBERT J- GR AM LEWIS Roam. l I

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Aug. 22, 1933. R H M r AL 1,923,864

BRUSH PLATE ASSEMBLY Filed Dec. 27, 1930 3 Sheets-Sheet 3 [MG/7&0? HERBERT J. GRAHAM LEWIS A. DARIJNG 3 1 I I flifiorneyi Patented Aug. 22, 1933 UNITED STATES Piraeus?!orriosi Bnusn i delphia, Pa assignors to Electric ServiceSupplies Company, Philadelphia, Pa., ,a Corpora;

tion of Pennsylvania Application December 27, 1930 Serial No. 505,084

11 Claims. (01. 171-324) This invention relates generally to electric generators and the like and more particularly to improvements in the construction of the rigging for supporting the commutator brush holders and their associated parts. I

Heretoiore and prior to this invention considerable difficulty has been encountered due to leaking or stray currents in direct current generators, this condition being especially serious in the case of generators employed for the head lighting of locomotives, train control, train sig- I181 systems and the like. One cause of this leakage or stray current is due to the faulty design or the commutator brush rigging or mounting, various attempts having been made from time to time to cure this fault by suitably insulating the brush holders from their supporting structure. Because of the relatively severe vibration to which the brush rigging is ordinarily subjected during the operation of the generator, the usual devices resorted to for supporting the brush holders in insulated relation with respect to each other and to the generator housing have failed. It is to overcome these difficulties that the present invention has been developed.

Among the. principal objects of the'present invention is, to provide a brush plate assembly or rigging which is adapted to support thecommutator-brush holders with sufficient rigidity to overcome vibration when the generator is in use; to provide a supporting structure for the brush holders by virtue of which the current leakage from the brush holders to the supporting framework of the generator is decreased to a veritable minimum, if not entirely eliminated; to provide an insulating plate upon which the brush holders are mounted and which is reinforced-in such manner as to withstand the injurious effects of vibration and temperature variations during the operation of the generator; to provide a brush plate assembly which is capable otsupporting two sets of commutator brushes respectively adapted for operative coaction with the separate commutators of a two-voltage generator, the assembly being so designed .as to effectively insure against direct metallic contact between the brush sets as well as between each of the latter and thegenerator housing; and to generally provide a structurally simple, inexpensive and durable brush rigging which may be readiiy attached to or detached from the generator housing as a compact, self-contained unit without necessitating the separate removal of the brush holders and their associated parts.

Other objects andadva-ntag-es of the invention will be apparent more fully hereinafter.

'The invention consists substantially in the combination, construction, location and relative arrangement of parts, all as will-appear in more or less detail hereinafter, as shown in the ac 5 companying drawings and as finally pointed out in the appended claims. In the accompanying drawings the invention has been illustratedin conjunction with a generator forming part of a turbo-generator unit, it being understood, or course, that the invention is not intended to be limited solely to the type of unit shown but may be employed in connection with other types of direct current generators as well as direct cur rent motors. In the said draWingst- Figure l is an elevational View of a turbogenerator unit, the generator unit or" which the present invention forms a part being partially shown in section; I q 7 Figures 2 and 3 are vertical cross-sectional views taken on the lines'22 and"3-3, respectively, of Figure 1';

Figure 4 is a vertical cross-sectional view of the brush holder supporting unit per se; Figure 5 is an elevational view of the cuter face of the unit shown in Figure 4 and Figure 6 is arr-enlarged viewtaken on the line 6-6 of Figure 2 and showing "a detail or the invention. 7

Referring now to the drawings 'andmore particularly to Figure 1 thereof, it'will be observed that the invention has been shown for purposes of illustration as incorporated in the generator 1-0 of a turbo-generator This generator 10 embodies the usual housing frame 11 within vwhich are suitably arranged the usual armature and "field magnets. In the particular instance shown the generator armature embodies two sets of current generating coils for generating separate currents of different voltage. Op erativelyassocia-ted with the armature are a pair of commutators 12 and 13 commonlysupported upon the free end of the generatorshaft 14, one commutator being provided for each set of cur rent generating coils- Extending across the outer render the annular housing frame 11 is the rigging for supporting the commutator brushes fin operativerela-tion withrespect to the commutators 12 and 13, this rigging beingdesignated generally by the refer-7 ence numeral 1-5. As most clearly appears in Figure 4 this rigging 15 includes a substantially fiat plate :or disc 16 of insulating material. V This plate 16 is prererablyof circular rorm'jarid 11.0

is centrally apertured as at 17 to permit the same to be slipped axially over the commutators 12 and 13.

Secured to the peripheral edge or margin of the insulating plate 16 and projecting axially forwardly of the plane thereof is an annular member 18 of metal. This metallic annulus 18 is provided in the inner edge thereof with a circumferentially extending shoulder 19 to provide an annular seat or depression within which the insulating plate 16 is received. Extending radially inwardly of the metal reinforcing ring 18 are a plurality of circumferentially spaced projections 20 against the inner surfaces of which the plate 16 is adapted to be disposed in flatwise relation. The plate 16 and these radially extending projections 20 are commonly apertured to receive the securing elements 21, these latter being the form of tubular rivets for firmlyand permanently securing the plate 16 to the metal ring 18 in the relation shown.

The ring 18 is provided intermediate the opposite edges thereof with a circumferentially extending flange 22 which is adapted to be seated within a suitable annular seat or depression 23 formed in the outer end of the housing frame 11 of the generator. Formed integrally with the annulus 18 are a plurality of angularly shaped arms 24 the free ends 25 of which are disposed in a plane substantially paralleling and axially offset from that of the insulating plate 16. In the particular instance shown (see Figure 5) three arms 24 are employed, the free ends 25 thereof being each provided with an interiorly threaded aperture 26.

Adapted to be supported upon the arms 24 in spaced relation with respect to the insulating slate 16 is an auxiliary plate 27, also of insulating material. As appears most clearly in Figure 5 the plate 27 is of substantially triangular shape having apertures 28 formed in the several corners thereof through which suitable screws 29 may be inserted for threaded engagement with the tapped holes 26 respectively provided in the arms 24 of the metallic reinforcing ring 18. It will be observed that the auxiliary plate 27 is arcuately cut out as at 30 to provide a suitable clearance for the outer armature 13. It will be understood that when the plate 27 is mounted in position upon the ring 18 as just described it is disposed in a plane substantially parallel to but axially offset from that of the insulating plate 16.,

These insulating plates 16 and 27 respectively constitute the supports for the brush holders which are operatively associated with the commutators 12 and 13. It will be observed that the commutator 12 is provided with four current collecting brushes 30, which latter are slidably retained by suitable brush holders 31 31 31, and 31 respectively mounted upon the insulating plate16., The commutator 13, on the other hand;,is in the present instance provided with only two current collecting brushes 32 which are slidably retained by thebrush holders 33 and 33 mounted upon the insulating plate 27'. The brush holders are all identical in construction and in each instance the brushes respectively associated therewith are radially urged toward the commutators under the influence of spiral springs 34 respectively coiled about the screw studs 35. In accordance with V the common practice the brushes are electrically connected to their respective holders by flexible conductors (not shown).

As appears quite clearly in Figures 2 and 3 the brush holders 31 31*, 31 and 31 are selar rivets 36 are projected.

In substantially similar fashion, the brush holders 33 and 33 are securely mounted upon the auxiliary plate 27 by means of the tubular rivets 38. One of these rivets, designated as 38', is preferably interiorly threaded as at 39 for threadedly receiving the end of a split pin 40. The free end of this pin is adapted to be axially inserted into the bore of the tubular rivet 36' when the plate 2'7 is positioned upon the annular ring 18 whereby to not only constitute a supporting element therefor which is auxiliary to the supporting arms 24 of the metal reinforcing ring but to also provide anefiective electrical connection between the brush holder 33 which cooperates with the commutator 13 and the brush holder 31 which cooperates with the commutator 12. It will be understood that in practice the positive brush holders 31 and 31 (32 volt) for the commutator 12 are connected together by the conductor 41 which latter is in turn connected to the positive 32 volt terminal of the generator by the conductor 42 which is threaded through a suitable aperture .43 provided in the plate 16. The negative brush holders 31 and 31 (32 Volt) for the commutator 12 are connected together by the conductor 44 and through the pin 40 to the negative brush holder which relates primarily to the plate assembly a or rigging for supporting the brush holders in operative position and in insulated relationship with respect to the associated parts of the generator. Suitably arranged to cover the rigging and the several parts associated therewith is a protective cover or door 4'7.

While in the present instance we have chosen to illustrate the invention as incorporated in a rigging for supporting a dual set of brush holders, it is to be understood that in those installations where only one set of brushes is employed, the auxiliary plate 27 will be dispensed with and the metal reinforcing ring 18 will be formed without the radially extending arms 24. It will of course also be apparent that the annular metallic ring 18 may be applied to the peripheral or marginal edge of the insulating plate 16 by other means than that herein shown and described without departing from the essential spirit of the invention-namely, the provision of a unitary'brush plate assembly the principal element of which includes a support of insulating material which is reinforced in its marginal edge by a metallic annulus. We have found by experience that a rigging constructed in accordance with and embodying the principles of Obviously by changing the number our invention not only efiectively insures against the leakage of current from the brush holders to the generator frame or housing but also is capable of withstanding the relatively severe .vibration to which generators are ordinarily subjected when used particularly in the railway field. Another important feature of our present invention resides in the fact that the rigging is in the form of a self-contained unitary assembly capable of being readily secured in or removed from operative position merely by the removal of a few screws and without necessitating the disorganization or removal of the several parts carried thereby.

It will be understood that the invention is susceptible of various changes and modifications without departing from the real spirit or principles thereof and it is accordingly intended to claim the same broadly as well as specifically as indicated by the appended claims.

What is claimed as new and useful is:-

1. A brush plate unitary assembly including a relatively rigid insulating supporting plate for a plurality of brush-holders, and a metal reinforcement for said plate extending about the peripheral edge thereof, said insulating supporting plate being maintainable in fixed position with respect to a support for said assembly by said metal reinforcement.

2. In a commutator brush rigging, a unitary assembly including an insulating supporting disk, a reinforcing member secured to and extending about the peripheral edge of said disk, and a second insulating disk supported by said reinforcing member in spaced, parallel relation with respect to said first disk.

3. In a commutator brush rigging a unitary assembly including a centrally apertured relatively rigid plate of insulating material adapted to support a plurality of brush holders, a plurality of brush holders operatively mounted upon said plate, and metallic means for strengthening and lending rigidity to said insulating plate, said means being permanently included as a part of said assembly and adapted to support the same in fixed position with respect to a support therefor.

4. In a commutator brush rigging, a unitary assembly including a centrally apertured relatively rigid plate of insulating material adapted to support a plurality of brush holders, a plurality of brush holders operatively mounted upon said plate, and metal reinforcing means secured to the marginal edge of said insulating plate, said reinforcing means being permanently included as a part of said assembly and provided with an annular seat for centering the assembly against the commutator end of a generator housing.

5. In a commutator brush rigging, a unitary assembly including a centrally apertured plate of insulating material adapted to be slipped over a commutator, a metal reinforcing ring permanently secured to the marginal edge of said plate, and a radially extending flange on said ring adapted for accommodation within the commutator end of a generator housing whereby to center said plate with respect to the commutator.

6. A commutator brush rigging including a main plate of insulating material, an auxiliary plate of insulating material, a pair of commutator brush sets respectively supported by said plates, and a metal reinforcing ring secured to the peripheral edge of said main plate and provided with means for supporting said auxiliary plate in axially spaced relation with respect to said main plate. I

"I. In a commutator brush rigging, a unitary assembly including a relatively rigid insulating plate adapted to surround the inner end of a commutator and to support a plurality of brush holders, a plurality of brush holders supported upon said plate in operative relation with respect to said commutator, and a metal ring permanently secured to the marginal edge of said insulating plate, said ring serving commonly as a reinforcement for the plate and as means for centering the same within the commutator end of a generator housing.

8. A commutator brush rigging including a main plate of insulating material arranged in embracing relation about the inner end of a commutator, a plurality of brush holders supported by said plate in operative relation with respect to said commutator, a metal reinforcing ring secured to the marginal edge of said main plate, said ring being provided with a plurality of circumferentially spaced arms axially offset from said main plate, an auxiliary insulating plate supported by said arms, said auxiliary plate being disposed substantially in the plane of the inner end of a second commutator arranged in advance of said first commutator, and

a plurality of brush holders supported upon said auxiliary plate in operative relation with respect to said second commutator.

9. In a commutator brush rigging, in combination, a unitary assembly including a pair of insulating plates arranged in spaced parallel relation, a metal ring secured to and extending about the peripheral edge of one of said plates and having a plurality of radially inturned arms to which the other of said plates is secured, two sets of brush holders respectively mounted upon said plates, and means extending between a brush holder of one set and a brush holder of the other set to effect an electrical connection therebetween.

10. In a brush rigging, in combination, a main plate of insulating material, a metallic reinforcing ring extending about and secured to the peripheral edge of said plate, a brush holder supported upon said plate by means of one or more tubular rivets, an auxiliary insulating plate adapted to be supported by said ring in spaced parallel relation with respect to said main plate, a brush holder mounted upon said auxiliary plate, and a pin projected from said brush holder into the bore of one of the securing rivets for said first brush holder whereby to effect an electrical connection between said brush holders. 11. In a brush rigging, in combination, a main plate of insulating material, a metallic reinforcing ring extending about and secured to the peripheral edge of said plate, a brush holder supportedupon said plate by means of one or more tubular rivets, an auxiliary insulating plate adapted to be supported by said ring in spaced parallel relation with respect to said main plate, a brush holder mounted upon said auxiliary plate, and a pin projected from said brush holder into the bore of one of the securing rivets for said first brush holder whereby to effect an electrical connection between said brush holders, said electrical connection being disruptable upon detaching said auxiliary plate from said ring.

HERBERT J. GRAHAM. LEWIS A. DARLING.

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