US2301421A - Dynamoelectric machine - Google Patents

Description

Patented Nov. 10, 1942 DYNAMOELECTRIC MACHINE Alvin M. Klingner and Martin Neuner, Fairview, N. J assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application April 28, 1941, Serial No. 390,816

1 Claim.

This invention relates to dynamo-electric machines, and particularly to commutator-engaging brush assemblies for use in dynamo-electric machines.

An object of the invention is to improve the construction of brush assemblies, particularly with respect to the pressure exerted on the individual brushes to maintain the brush in good contact with the commutator surface.

It is common practice to employ a strip of spring steel to urge each brush into operative position, and to yieldably maintain engagement, regardless of wear which gradually shortens the brush length; and in order to regulate the de-- gree of pressure of these springs it is customary to provide adjusting means. The present invention involves certain improvements in the manner of making such adjustments and in the adjusting means itself.

Objects of the invention, therefore, include improvements in the method and means of brush pressure adjustment, in dynamo-electric machines.

These and other objects of the invention will become apparent from inspection of the following specification when read with reference to the accompanying drawing, wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claim for this purpose.

In the drawing,

Fig. 1 is a transverse sectional view of a machine equipped with brush assemblies embodying the present invention; and

Fig. 2 is a view at a right angle to the viewpoint of Fig. 1.

In these figures there is indicated at I the casing of an electric unit (motor or generator).

The commutator 2 is shown provided with a pair of brushes 3, each slidably mounted in a bracket 4 projecting from an annular boss 5 on the end wall of the casing I; the brackets 4 being held to casing surface 5 by suitable fastening means 6. A flat strip I of resilient, current conducting spring metal is coiled spirally about (and fastened to) a pin 9 adjacent each brush-holder 4, the latter having apertured extensions II to receive and secure these spring anchoring pins 9. Each spring coil terminates in an outwardly bent, brush-engaging portion 8, wherefore there is applied to each brush a yielding pressure sufficient to insure good contact with the commutator.

The novel means for regulating, and holding, the desired setting of each brush spring I will now be described. Secured to each pin 9 is a toothed sector I 3 with fine pitch teeth adapted to mesh with correspondingly pitched teeth, or threads, of a worm-screw element l4; each screw l4 being supported in a bracket I6 forming part of the casing assembly, and each screw also being provided with a polygonal portion I! accessible for application of a wrench thereto, the wrench being insertible through slots l8 that are normally covered by plates l9. Leads 2| form the usual electrical connections for the brushes.

Turning of either screw I4, by wrench action or otherwise, will of course vary the tension in the associated spring I, and will correspondingly vary the pressure on the adjacent brush 3. The setting thus obtained will remain constant until again revised manually, as the worm l4 acts as a look upon the sector [3 and thereby prevents any shifting of the inner end of the spring, attached to pin 9.

It will also be seen that adjustments may be made without removing any of the parts of either brush assembly.

In the claim the term commutator embraces any rotary contact member, or group of contact members, whether for direct or alternating cur- What is claimed is:

In combination with a spirally wound spring having its outer end bearing upon a commutatorengaging brush, a toothed sector connected to the inner end of said spirally wound spring, a wormscrew normally maintaining said toothed sector in predetermined position, said worm screw being rotatable to swing said sector and thereby vary the pressure applied by said spring to said brush, a supporting bracket for said worm-screw, and a casing assembly enclosing said wormscrew, said bracket being an integral part of said casing assembly.

ALVIN M. KLINGNER. MARTIN NEUNER.

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