Patent ID: 9664270
Date: 2017-05-30
CPC Classifications: A01D,F16H

Claim:
1. A hydraulic drive mechanism, comprising: a housing comprising a first housing component joined to a second housing component to form a sump, the first housing component having a pump running surface, a motor running surface and internal porting formed inside the first housing component to join the pump running surface and the motor running surface; a valve disposed in a valve bore formed in the first housing component, the valve bore having a first end open to the sump on an internal surface of the first housing component and a second end open to the internal porting; a pump rotatably disposed on the pump running surface and a motor disposed on the motor running surface, wherein both the pump and the motor are hydraulically connected to the internal porting; an output shaft driven by the motor, the output shaft having a first axis of rotation and comprising a first shaft end extending out a first side of the housing and a second shaft end extending outside a second side of the housing opposite the first side; a pump input shaft engaged to and driving the pump, wherein the pump input shaft has a second axis of rotation which lies on a common plane with the first axis of rotation; and a swash plate engaged to the pump, and a trunnion comprising a first arm engaged to the swash plate to rotate the swash plate to vary the output of the pump, and a second arm which rotates with the first arm, the second arm having an operative end that is capable of engaging the valve, whereby the operative end of the second arm opens the valve to permit a hydraulic connection between the internal porting and the sump through the valve bore when the trunnion is rotated to a predetermined position.