Brush assemblies with back plate providing brush support

Abstract

Detailed are brush assemblies for electric motors. The assemblies may include retention springs or other mechanisms designed to bias brushes away from surfaces of commutators during assembly of the motors. Such retention mechanisms additionally may be fitted into cavities in associated cover plates following motor assembly. The cover plates further may include tabs which, in use of the motor, assist in supporting side surfaces of the brushes and in orienting the plate relative to a corresponding brush card.

1 . A brush assembly for an electrical motor, the brush assembly comprising: 
 a. a brush card;    b. a brush positioned, at least in part, in the brush card;    c. a cover plate attached to the brush card, the cover plate comprising means for orienting its position relative to the brush card; and    d. resilient means, in contact with the brush, for restraining movement of the brush in at least one direction.    
   
   
       2 . A brush assembly according to  claim 1  in which the orienting means comprises at least one tab.  
   
   
       3 . A brush assembly according to  claim 2  in which (a) the brush card comprises a housing for the brush, the housing having an incomplete side wall, and (b) the tab at least partially completes the incomplete portion of the side wall.  
   
   
       4 . A brush assembly according to  claim 3  in which the incomplete side wall and the tab help support the brush.  
   
   
       5 . A brush assembly according to  claim 1  in which the resilient means engages, and is adapted to move relative to, the brush card.  
   
   
       6 . A brush assembly according to  claim 5  in which the brush card defines a channel and the resilient means comprises a flange engaging the channel.  
   
   
       7 . A brush assembly according to  claim 1  in which the resilient means comprises a spring.  
   
   
       8 . A brush assembly according to  claim 7  in which the spring includes two curved sections, each having a flanged end.  
   
   
       9 . A brush assembly according to  claim 8  in which the spring further includes a flat section opposite the flanged ends.  
   
   
       10 . A brush assembly according to  claim 1  further comprising a biased spring, positioned at least partly within the brush card in contact with the brush, for biasing the brush into a region bounded by the brush card.  
   
   
       11 . A brush assembly according to  claim 10  in which the resilient means counteracts the bias of the biasing spring.  
   
   
       12 . A brush assembly according to  claim 1  in which (i) the cover plate has a first side facing the brush card and a second side opposite the first side and (ii) the second side has a cavity therein.  
   
   
       13 . A brush assembly according to  claim 12  in which the brush card is configured so that the resilient means may be moved into the cavity when it no longer is needed to restrain movement of the brush.