Automatic machine motion restricting mechanism

摘要

Fluid links are interposed between manual levers which control the motions of a machine such as a construction crane and associated spool valves which regulate the machine motions. In normal operation within predetermined safe limits of machine motions, pressurized fluid delivery valve means connected with the fluid links is conditioned by a normal signal from a safe machine motion sensing means and delivers pressurized fluid to the fluid links rendering the links "hard" so that the manual levers are enabled to effect safe machine motions. When an unsafe machine motion is sensed by the sensing means, the valve means responds to the interruption of the normal signal from the sensing means and is conditioned to interrupt delivery of pressurized fluid to the fluid links thus rendering the links "soft" and thus disabling the manual levers from causing machine motions beyond safe limits.