Patent ID: 8240145

Claim:
A hydrostatic assembly comprising: a pump that includes a yoke and an associated rotating group for receiving hydraulic fluid and outputting hydraulic fluid under pressure, the pump yoke having a bucket portion and an arm portion, at least one fluid passage extending through the pump yoke for fluid communication with the pump rotating group; a motor that includes a yoke and an associated rotating group for receiving hydraulic fluid under pressure and outputting mechanical energy, the motor yoke having a bucket portion and an arm portion, at least one fluid passage extending through the motor yoke for fluid communication with the motor rotating group; the arm portion of the pump yoke and the arm portion of the motor yoke have associated coupling portions for placing the at least one fluid passage in the pump yoke in direct fluid communication with the at least one fluid passage in the motor yoke, the coupling portions being rotatable relative to one another to enable relative rotation between the pump yoke and motor yoke so that at least one of the pump and motor has a variable displacement.