Means for prventing reverse drive through a hydrostatic transmission

Claim 1

A means for automatically preventing a motor, which is hydraulically driven by a pump and mechanically drives an inertial load through a transmission shaft, from pumping caused by being driven by said inertial load, comprising a blocking means for blocking a reverse power transmission from said inertial load to said motor through said shaft, at said shaft, said blocking means including a plurality of brake elements and a brake disc, said brake disc being fixed to said shaft and arranged between said brake elements, said brake elements being fixed to pistons inside cylinders, respectively, hydraulic means coacting with said pistons for automatically urging said pistons hydraulically against said brake disc with a hydraulic medium provided for the power transmission, when an excessively high pressure occurs in said medium as a result of said reverse power transmission from said inertial load to said motor, and a pair of main conduits for driving said motor by said pump, and a changeover valve means coacting with said cylinders and main conduits for automatically providing communication therebetween when said pump drives said motor.