US433523A

US433523A - And william d

Info

Publication number: US433523A
Authority: US
Publication date: 1890-08-05
Anticipated expiration: 1907-08-05

Description

Y UNITED STATES PATENT OFFICE.

JAMES WV. EASTON, OF NEYV YORK, N. Y., ASSIGNOR TO P. MINTURN SMITH, OF PLAINFIELD, NEXV JERSEY, AND WILLIAM D. PERRY, OF BROOK- LYN, NE\V YORK.

COMMUTATOR FOR DYNAMOS.

SPECIFICATION forming part of Letters Patent No. 433,523, dated August 5, 1890. Application filed November 16, 1889. Serial No. 330,593. (No model.)

To all whom, it may concern:

Be it known that I, JAMEs WV. EAsTON, a subject of the Queen of Great Britain, and a resident of the city of New York, in the county and State of New York, have invented certain new and useful Improvements in Commutators for Dynamo-Electric Machines, of which the following is a full, clear, and exact description, reference being had to the accompanyin g drawings, forming part of this specification.

My invention relates to dynamo-electric machines and motors, and consists in a novel form, construction, and arrangement of the sections of the commutator.

It consists, further, in the provision of means for preventing short-circuiting between the sections of my improved commutator; and it consists, further, in the novel construction, arrangement, and combination of parts hereinafter more specifically described and claimed.

In dynamo-electric machines the requisite pressure of the brushes against the commutator-cylinder produces sufficient friction to soon wear away the surface of the commutator, and in such machines as heretofore constructed a channel is speedily formed around the periphery of the commutator where the brushes come in contact with it. The sides of this channel are not straight and true,but are rounded or beveled, owing to the vibration of the shaft of the machine, and also to the variation in the position of the brushes. The bottom of the channel also becomes uneven, and in consequence the contact between the brushes and the commutator will be very intimate at some points in the width of the brushes, while at others they will not be in contact at all. This causes an excessive amount of sparking and such a variation in the operation of the machine that the operation of the apparatus connected with it is often seriously interfered with.

The object of my invention is to prevent the uneven wearing away of the commutatorsections and to afford an even bearing for the extremities of the brushes until the com mutator is entirely worn out.

In the accompanying drawings, Figure 1 is a longitudinal sectionalview of a commutator constructed in accordance with my improvements. Fig. 2 is a transverse sectional view thereof on the line 2 2, Fig. 1. Fig. 3 is a view in elevation of one of the sections of my improved commutator, and Fig. 4 is a corresponding view of one of the sections of a commutator of the ordinary construction showing the groove worn therein by the brushes of the machine.

Similar letters of reference are used to indicate corresponding parts in all the views.

The sleeve or hub A is adapted to be suitably secured to the shaft of the machine, and

serves to support the commutator-sections B in any usual manner. As shown, the inner end of the sleeve A is provided with the undercut flange a, and the outer end of the sleeve is screw-threaded to receive the nut O, which bears against the undercut collar D, which is adapted to slide along the sleeve A. The commutator-sections are suitably insulated from the sleeve and collar, and also from each other, by strips or rings of insulating material E. Then the commutator-sections are placed in position, the nut O is screwed up tightly against the collar D, which in turn exerts sufficient pressure against the sections to hold them firmly in place.

The commutator-sections B consist, preferably, of thin sections of copper, and are preferably provided with the projecting arm I) for the attachment of the armature-coils. They are advantageously made considerably deeper than is ordinarily done, so that they will project out beyond the outer surface of the collar D. Each of the sections B is provided with a slot 1) at a distance from the outer edge of the section equal to the width of the brushes to be used. WVhen the sections are in position, these slots 1) form a continuous channel around the periphery of the commutator, and the depth of the slots is such that the channel will extend down to the point to which the sections can be worn before being discarded. These slots maybe formed in the sections in any desirable way. For instance, they may be formed separately before the sections are mounted on the shaft, or they may be cut simultaneously after the sections are in position, care being taken that the edges of the channel are even and at right angles to the axis of revolution. As thus constructed, an even wearing or contact surface is provided for the commutator of the exact width of the brushes, and this surface is evenly maintained until the sections are Worn down to the depth of the channel or groove, when the sections may be replaced by new ones.

In order to prevent the possibility of the short circuiting of the commutator, which might ensue if the groove were to become filled with dust, dirt, and abraded metal, I fill the groove with any suitable insulating material 12 preferably such as can be readily removed in layers as the contact-surface of the commutatoris Worn away. I prefer to fill the groove in the following manner, although it is to be understood that I do not limit myself thereto: A layer of varnish or glue is first putinto the bottom of the groove and then a layer of flaxthread-such as is used by harness or shoemakers-is wound therein. Thisis then coated with the varnish or glue and another layer of thread is wound in, and so on until the groove is filled. The glue or varnish serves to fill up all cracks and crevices, and the thread prevents it from falling out or cracking if it becomes heated. The thread is disposed in even layers and can be easily cut through with a knife, thus permitting layer after layer to be readily removed as the contact-surface of the commutator is Worn down. As stated, however, any other suitable insulating material may be used, and it may be inserted in the groove in any desirable manner.

I use the Words contactsurface in the claims to designate that particular portion of the commutator against which the brushes are adapted to bear.

Having thus described my invention, What I claim as new, and desire to secure by Letters Patent, is-

1. A commutator provided with a groove or channel to limit the width of its contact-surface, such groove being filled with insulating material, substantially as and for the purposes set forth.

2. A commutator provided withagroove or channel to limit the width of its contact-surface, such groove being filled with insulating material in separable layers, substantially as and for the purposes set forth.

JAMES WV. EASTON.

Witnesses:

S. G. METoALF, WILLIAM Lnvn.