Patent ID: 6244449
Filing Date: 2001-06-12
Classification: B66D

Abstract:
A crane having an upper works rotatably mounted on a lower works, a load hoist line for lifting loads, a load hoist line drum onto which said load hoist line is reeled, and a drum drive assembly, wherein said drum drive assembly comprises:a) a hydraulically powered motor for rotating said load hoist line drum to either pay out or reel in said load hoist line;b) a first brake for inhibiting the rotation of said motor;c) a second brake connected to said load hoist line drum for inhibiting the rotation of said load hoist line drum; andd) a jaw clutch having an axis of rotation and connecting said motor to said load hoist line drum, said jaw clutch being disengagable to permit said load hoist line drum to rotate independently of said motor and under the influence of gravity acting upon a load being supported by the load hoist line, said jaw clutch comprising a drive clutch plate having a plurality of equally spaced teeth and a driven clutch plate having a plurality of equally spaced teeth, wherein said teeth of said drive clutch plate and said teeth of said driven clutch plate are oriented in a direction parallel to said axis of rotation, further wherein said teeth of said drive clutch plate interlock with said teeth of said driven clutch plate to engage said jaw clutch, further wherein a spring is used to engage said teeth of said drive clutch plate with said teeth of said driven clutch plate, said spring exerting a force on said driven clutch plate so as to bias said drive clutch plate and said driven clutch plate together.