Patent attributes
A dishwasher includes a drain pump assembly having a chopper assembly coupled to an impeller and driven by a synchronous motor. The chopper assembly includes an impeller housing that includes a central hub portion for pivotally supporting a plurality of rotatable chopper blades. An apertured plate is secured to the impeller housing and maintained in a spaced relationship from the chopper blades. The chopper assembly is coupled to the impeller through an axially sliding drive mechanism that facilitates assembly of the chopper assembly into the impeller housing. The synchronous motor drives the chopper blade in a first direction until encountering a hard soil particle whereupon the chopper blades can pivot so that the chopper assembly can continue to operate or, if the chopper blade becomes jammed, the synchronous motor can oscillate to hammer the hard soil particle until it becomes small enough to pass through the apertured plate.
