Patent ID: 7234659

Claim:
A crushing apparatus that is attachable to a working arm of a self-propelled platform or truck, and that comprises crushing arms capable of being closed or opened by a hydraulic actuator as well as a swiveling mechanism having a hydraulic motor for driving the crushing arms to swivel, the crushing arms movable between a closed position and a fully open position; the apparatus further comprising a branch diverged from a hydraulic fluid path communicating with the actuator for closing and opening the crushing arms, with this path feeding the hydraulic fluid to said actuator when the crushing arms are driven to open, and the branch having disposed therein an on-off means that normally keeps the branch closed, but will open this branch so as to drive the motor only when a pressure applied to the actuator rises above a predetermined level while the crushing arms remain opened, and a delay device incorporated in the branch such that when a pressure therein or in the hydraulic fluid path has exceeded a limit and a given period of delay time has lapsed, an amount of hydraulic fluid will be supplied to the swiveling mechanism after the crushing arms have fully opened.