Lift crane with mast-raising mechanism

摘要

A mast-raising mechanism for raising a mast of a mobile lift crane to an operating position includes a hydraulic cylinder extendable to raise the mast. The hydraulic cylinder includes a first end pivotally coupled to a rotating bed of the crane and a second end spaced apart from the first end. A first arm includes a first end pivotably coupled to the second end of the hydraulic cylinder. The hydraulic cylinder extends to press the first end against a bearing surface on the mast. The first arm also includes a second end spaced apart from the first end. A second arm includes a first end proximate the second end of the first arm and a second end spaced apart from the first end. The second end of the second arm is pivotably connected to the rotating bed. A biasing mechanism urges the first arm towards the second arm.

主权项

1. A mast-raising mechanism for raising a mast of a mobile lift crane, said crane including movable ground engaging members mounted on a carbody allowing said crane to move over the ground, a rotating bed rotatably mounted on said carbody, said mast being pivotally connected to said rotating bed, said mast having a lower surface oriented towards said rotating bed when said mast is stowed in a substantially horizontal position for travel, said mast-raising mechanism comprising:
a) a bearing surface coupled to said lower surface of said mast; b) a linear actuator extendable to raise said mast, said linear actuator including a first end pivotally coupled to said rotating bed and a second end spaced apart from said first end of said linear actuator; c) a first arm including a first end pivotably coupled to said second end of said linear actuator, said first end of said first arm including a plate oriented to press against said bearing surface to raise said mast when said linear actuator is extended, and a second end spaced apart from said first end of said first arm; d) a second arm including a first end proximate said second end of said first arm, and a second end spaced apart from said first end of said second arm, said second end of said second arm being pivotably connected to said rotating bed; and, e) a biasing mechanism coupling said second end of said first arm to said first end of said second arm, said biasing mechanism urging said first arm towards said second arm.