Snag load protection system for a crane

摘要

A snag load protection system for a train including a guide frame, a sheave housing slidably received within the guide frame, and a hydraulic cylinder connected to the guide frame and to the sheave housing. The hydraulic cylinder serves to exert a compressive force against the sheave housing so as to resist relative movement between the guide frame and the sheave housing when forces exerted by the sheave housing are within a predetermined value. A relief valve is connected to the hydraulic cylinder for releasing hydraulic fluid from the hydraulic cylinder when the force is greater than the predetermined value. Pressure and position limit switches are connected to a motor so as to stop the movement of a hoist rope when forces exceed the predetermined value.