Suspending support for a crane cab

摘要

A support apparatus for the operator's cab of an overhead crane. The crane has a rigid depending mast and an intermediate mast and carriage vertically movable on the rigid mast for lifting and carrying a load. A hoist is mounted on the crane and attached to the carriage for raising and lowering the carriage, the intermediate mast and the load at normal operating speeds. The support apparatus includes a first support affixed to the cab and the intermediate mast for supporting the cab on the intermediate mast during normal operating speeds of the intermediate mast. The first support permits detaching the cab from the intermediate mast upon the occurrence of an excessive lowering operating speed of the intermediate mast. A second support affixed to the cab and to an overhead support of the crane then supports the cab in a suspended manner and the intermediate mast drops toward the floor below the crane without the cab. A sensing mechanism may also be provided for detecting excessive lowering overspeed of the intermediate mast and producing an indication of the overspeed to the second support. The second support is responsive to the excessive lowering speed indication of the sensing mechanism to support the cab.