US1507566A - Commutator brush and method of making it - Google Patents

Description

fiaepico 9 1924.

v. G. APPLE COMMUTATOR BRUSH AND METHOD OF MAKIRG IT Filed Sent. 27. 1920 di'naelzi a; /9 u ug Patented Sept. 9, 11924 unit VINCENT (3-. APPLE, OF DAYTON, OHIO.

COMMU'I'ATOR BRUSH AND METHOD OF MAKING- IT.

Application filed September To all whom it may concern.

Be it known that I, VINCENT G. APPLE, a citizen of the United States, residing at Dayton, in the county of Montgomery and State of OlllO, have invented certain new and. useful Improvements in 'Commutator Brushes and Methods of Making Them, of which the following is a specification.

This invention relates to improvements incommutator brushes and a method of making them.

One of the objects of the invention is to improve the quality and efliciency of collecting brushes for electric purposes.

Another object is to cheapen the mode of construction.

A more specific object is to reduce the electrical resistance of brushes of given dimensions. ,7

Another object is to render brushes made graphite more tenacious and adhesive without making them objectionably dense and hard, thereby destroying the lubricating quality of the graphit Another object is to incorporate graphite with a suitable binder in a metal fabric structure so that the metal and graphite will be uniformly distributed throughout the finished brush.

Another object is to make a brush of compacted graphite incorporated with compacted phenolic condensation product.

Other, further and more specific objects of the invention will become readily appar cut, to persons skilled in the art, from the following description, when taken in conjunction with the drawings, forming a part thereof.

The drawings show conventional means by which my invention may be carried into effect.

Fig. l is a strip of wire cloth, of relatively fine mesh, made of small copper or aluminum wires, or an alloy thereof, or of any other soft, suitable electrically conducting reticulate strips of metal.

Fig. 1 shows a similar sheet of cloth with a superimposed strip of graphite made plastic by incorporating therewith a suitable binder or adhesive.

Fig. 2 is a sectional view of the formed roll or cylinder showing a base of metal fabric rolled into a helical form with an interposed sheet of raphite laced therein, ready to be pressed into t e rectangular shape shown in Fig. 3.

the shape shown in 27, 1920. Serial No. 413,217.

Fig. 4 shows the reduced metal structure and graphite pressed therein, and I Fig. 5 is a perspective view of the complete brush for commutator collection.

In carrying the invention into effect, I procure a suitable piece of wire cloth 10 made of a good conducting metal, such as copper, aluminum, or the like, or an alloy thereof. I then roll it into the shape shown in Fig. 2, that is to say, in substantially helical form, with a graphite plastic between convolutions, and place it in a die 11 to be compressed by the plunger 12, into the shape shown in Fig. 3, and then heated to set the cementitious binder. When the metal structure has been compressed into Fig. 3, it is substantially the same size as the brush 15' shown in'Fig. 5. It contains a uniform number of layers on its sides and ends. To make the graphite plastic, I mix finely divided graphite with a liquid phenolic condensation product, which hardens to some extent by application of pressure and to a. greater extent by the application of heat, to form a dough. I then form it into thin narrow strips and lay the strip on a strip of metal cloth or fabric .(see Fig. 1) and roll the compound strip into a helical roll.

I may alternatively mix the graphite with the phenolic condensation product and after the compression of the cloth has been completed, then a quantity of graphite compound 13, in powder form, is placed in the die, above the cloth structure, which is resting upon an ejecting plate 14 and above that is the compound 13. The plunger 12 is now forced downwardly until it presses allof the graphite compound into and around the'cloth structure, as shown in Fig. 4;, so that when the brush 15 is taken from the die the metal or copper structure enclosed within the graphite is substantially invisible, at the same time the dimensions of the structure has not been greatly increased by the incorporation therein of the graphite com ound by pressure. The contents of the d1e are removed by tapping the ejecting rod 16.

In Fig. 3 the overlying layers of wire clothof the structure 10 arein substantial contact with each other but there is left between the layers the openings or voids due to the interlacing of the wires which are subsequently completely filled with the graphite.

- liquid condensation product is On account of the intimate relation of the metal structure to the graphite, the relatively light pressure is all that is necessary to compact the graphite sufiiciently to cause it to enter the metal structure and to hold it in its finished form and this is more pronounced when the graphite plastic is used, therefore, it is not so hard as to become objectionable as a result of its having lost its lubricating or friction reducing qualities by effect of excessive pressure. v

It will readily be seen that the metal is uniformly distributed throughout the entire brush structure and that the conductivity of the brush is greatly enhanced as the result of the presence of the metallic frame, and the metal being of a soft nature, it will not scratch or abrade the commutating surface.

In the accompanying drawings, I have shown the simplest means by which pressure may be applied to the part composing the brush.

When the powdered product is inchrporated with the graphite, application of heat is required while under pressure to make the brush structure sufficiently tenacious. Heat also hardens the structure when the formed into a dough with the graphite.

While it is not necessary to heat the brush structure to a degree required to carbonize the phenolic condensation product, as it is very satisfactory in operation without such treatment, the incipient sparks atthe commutator seem to accomplish this result at the contacting surfaces. I deem it advisable, however, to precarbonize the binder as high temperature not only completely carbonizes the ingredient but hastens the hardening operation.

It will be manifest'that many changes may be made in the structure, in carrying the invention into effect and in the described mode of manufacture and that furthermore, instead of using pressure the brush may be formed, in the manner described, by the effect of compression effected by blows delivered on the end of the plunger or a series of blows, the invention lying in'the readiness with which the graphite is incorporated in the brush structure and the method ursued in accomplishing the uniformity of its distribution, which provides a homo- (gleneoushrushof minimum resistance, proucing little friction on the commutator surface and which maybe rapidly and cheaply produced.

Having described my invention claim as new and desire to secure by Patent is:-

1. The method of making commutator brushes which consists in producing overlying layers of metal wire cloth;'compact-- ing the structure to definite dimensions and what I Letters forcing the commutator lubricating material into the structure to entirely fill the voids therein.

2. The method of making commutator brushes which consists in producing overlying layers of metal wire cloth; compacting the structure in a die to definite dimensions; and while being confined" in the die applying pressure to force a lubricating, electrically conducting material into the structure entirelyfilling the voids therein and without materially increasing the size of the metal structure.

3. The method of making commutator brushes which consists in producing a strip of metal wire cloth; winding compressing it into rectangular form, supplying graphite and subjecting it to pressure to force it into the voids in the metal form.

4. The method of making a commutator brush which consists in rolling an elongated strip of metallic wire cloth and a strip of graphite made plastic into cylindrical form; pressing the cylinder into rectangular form and forcing graphite into the voids of the wire structure.

5. A commutator brush of rectangular form having an equal number of compacted layers of a reticulate sheet at its sides and ends, the voids between the layers filled with compacted graphite and a covering of aphite held in place by theouter layer.

6. The method of making a commutator brush which consists in rolling a strip of reticulate sheet metal into cylindrical form; compacting the cylinder into rectangular form and coincidentally forcing graphite, incorporated with a binder, into the voids in the metal strip.

7. The method of making a commutator brush which consists in incorporating in a structure a comdivided graphite product binder, to Carbonize the reticulate metal laminated position comprising finely and phenolic condensation then baking the structure binder.

8'. The method of making a commutator brush which consists in making a plastic dough of graphite and a phenolic condensation product; compacting the dough to a form and heating the composition until the said product is thereby converted into carbon.

9. The method of making a commutator brush which consists in forming a strip 0 reticulate metal into a laminated structure; forcing into the voids thereof a compound consistlng of graphite and phenolic condensation product, thereby compacting the structure and the compound, then heating the composite structure until said product is converted into carbon.

In testimony whereof scribe my name.

VINCENT G. APPLE. v

I hereunto subit into a roll;.

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