US672604A - Commutator-brush and brush-holder. - Google Patents

Description

Yu 7 504 Patented Apr. 23, l90l.

v 1 R. LUND-ELL.v

COMMUTATOB BRUSH AND BRUSH HOLDER.

(Application filed om 10, 1900. (N 0 M o d a l UNITED STATES PATENT OFFICE.

ROBERT LUNDELL, OF NEW YORK, N. Y.

COMMUTATOR-BRUSH AND BRUSH-HOLDER.

SPECIFICATION forming part of Letters Patent No. 672,604, dated April 23. 1901.

' Application filed October 10, 1900. Serial No. 32,572. QNo modelh To all whom, it may concern:

Be it known that I, ROBERT LUNDELL, a citizen of the United States,residingat New York, borough of Manhattan, county and State of New York, have made a new and useful Invention in Oommutator-Brnshes and Brush- :Iolders for Dynamo-Electric Machines or Electric Motors, of which the following is a .pecification.

The present invention relates to improvenents in commutator-brush holders and )rushes, and has particular reference to that class of brushes whicli'are known as carbon brushes. It has for its objects, first, to reuce the heating by decreasing the total or ggregate contact resistance between the arushes and commutator; second, to prevent sparking (a) by increasing the contact resisttnce at the points where a high brush resist- M306 is needed to insure perfect commutaion, and (b) by decreasing the possibility of )reaking contact, owing to any slight unevenness on the surface of the commutator, and, third, to provide means for taking up the differentamounts of wire of the brushes due to their different qualities.

It is well known in the art that a low-resistance brush is desirable in order to keep the 0 R losses within proper limits; but that a high-resistance brush is needed to prevent sparking in cases where the brushes cannot be given the proper amount of lead on the commutatorfor example, railway-motors,

which must run in both directions without change of brush position.

Carbon brushes are now made with high-resistance edges and low-resistance centers, which seem to work quite well if the current density is low and other conditions favorable. I have, however, found that when these brushes are used under more severe conditions the center portion of the brush is eaten out until only the high-resistance edges make contact with the commutator. The present invention overcomes this diificulty and provides means for preventing rupture of contact, owing to a slight unevenness on the surface of the commutator, which rupture of contact would quickly aggravate the fault.

Referring now to the drawings, Figure 1 is a side elevational view of my novel brushholder and brush; and Fig. 2 is a sectional view of the same, taken at line 00 03 of Fig. 1.

Referring now to the drawings in detail, B, B, and B represent three carbon brushes which are pressed against the commutator, as shown, independent of one another by separate springs 8,8, and S The carbons are arranged to slide in hollow sleeves or guides contained in a holder H, which in turn is firmly secured to a rocker-arm or other support in the usual manner. The center carbon B is supposed to be made of special low-resistance material and may have a layer of fine copper gauze embedded in the center of its body, according to usual practice. To the upper part of the carbon, which is copper-plated, is soldered a copper piece A, to which in turn is soldered a flexible copper cable 0, the object being to provide a path of very low resistance from the comm utator-bars to the fixed part of the holder. Aspiralspring S and adjusting thumb-screw Tare provided between the extension H of the brush-holder and the brush-holder I-I itself in order to put the requisite pressure upon the carbon. The two outside carbons are supposed to be made ofhigh-resistance material. They are pressed against the commutator by flat springs S and S as clearly indicated in the drawings. The arrangement and construction of said springs are similar to the one described by me in a prior United States patent, No. 505,665, of September 26, 1893, and a minute description of the details is for this reason not considered necessary. It will of course be understood that if the dynamoelectric machine is to run in only one direction the construction of the brush -holders would be somewhat simpler, by reason of the fact that one of the highresistance brushes could be omitted.

I do not limit my invention to the specific details of structure and arrangement as to its application shown in theaccompanying drawings or hereinbefore described. I believe it is broadly new with me to combine two or more commutator-brushes of different conductive capacity and to locate them side by side upon the commutator of a dynamo-electrio machine or electric motor, each brush being secured in its position by an independent support and provided with independent means for feeding it forward as its contacting end is worn away by the commutator, and my claims hereinafter made are generic as to this feature.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

1. Two or more commutator-brushes of different resistance secured in independent supports of a brush-holder, and in such relation to each other that a high-resistance brush is located at the leaving edge of the low-resistance brush; in combination with means for causing said brushes to be fed forward independently of each other, substantially as described.

2. A brush-holder having three sets of independently-supported brushes, the center brush or brushes being of lower resistance than the two outer sets of brushes for the purpose of preventing sparking on the commutator; in combination with means for causing said brushes to be fed forward independently of each other.

A current-collecting device for a commutator consisting of several independently-supported brushes of carbon or other similar unyielding material located after one another on the periphery of the commutator, substantially as described.

4. A current-collecting device fora com mutator consisting of several brushes located after one another on the periphery of the com- 111 utator, said brushes being held by independent supports or pockets, which in turn are electrically united so as to constitute parts of eithera positive or a negative brush-holder.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ROBERT LUNDELL.

Witnesses:

C. J. KINTNER, M. F. KEATING.

Correction in Letters Patent No. 672,604, f

It is herebg certified that in Letters Patent No. 672,604, granted April 23, 1901,

upon the application of Robert Lundell, of New York, N. Y., for an improvement in Oommutator-Brushes and Brush-Holders, an error appears in the printed specification requiring correction, as follows: In line 25, page 1, the Word wire should read wear; and that the said Letters Patent should be read With this correction therein that the same may conform to the record of the case in the Patent Office.

Signed, countersigned, and sealed this 7th day of May, A. 1).,1901.

[SEAL] F. L. CAMPBELL,

Assistant Secretary of the Interior.

Oountersigned F. I. ALLEN,

Commissioner of Patents.

Correction in Letters PatentNo. 672,604.

It is herehg certified that in Letters Patent No. 672,604, granted April 23, 1901, upon the application of Robert Lundell, of New York, N. Y., for an improvement in Commutator-Brushes and Brush-Holders, an error appears in the printed specification requiring correction, as follows: In line 25, page 1, the word wire should read wear,- and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed, countersigned, and sealed this 7th day of May, A. D., 1901.

[SEAL] F. L. CAMPBELL,

Assistant Secretary of the Interior.

Oonntersigned F. I. ALLEN,

Commissioner of Patents.

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