FALL PREVENTION DEVICE OF ROBOT ARM COUPLING DEVICE

PROBLEM TO BE SOLVED: To improve a hydraulic circuit of a fall prevention device of a robot arm coupling device. SOLUTION: In a coupling structure where the weight or the like of a tool is applied in the separation direction in an operation state, a mechanically fixing mechanism for preventing a separation pressure from being applied to the hydraulic circuit is realized in a single valve structure as a mechanism for avoiding a falling risk due to malfunction. This fall prevention mechanism for the robot arm coupling device which avoids the falling risk and has the improved safety is attained in a simple mechanism. This fall prevention mechanism, as a mechanism for operating the safety valve, is provided by effectively using a two-position changeover valve by separately providing a mechanism for detecting a tool plate and operating a spool, and a mechanism for detecting a tool base and operating a valve body. COPYRIGHT: (C)2009,JPO&INPIT