| 摘要 |
A power shovel generally consisting of a support unit, a stiffleg operatively connected to the support unit for pivotal movement about a stiffleg pivot axis, a handle operatively connected to the stiffleg for pivotal movement about a handle pivot axis, a dipper mounted on the handle, a crowd system operatively connected to the handle for crowding and retracting the dipper and a hoist system for hoisting and lowering the dipper comprising at least one upper fluid actuated rod and cylinder assembly operatively connected at a lower end to the stiffleg and operatively connected at an upper end thereof to the handle on one side of the handle pivot axis, at least one lower fluid actuated rod and cylinder assembly operatively connected at a lower end thereof to the stiffleg and operatively connected at an upper end thereof to the handle on a side opposite to the operative connection of the upper end of the upper fluid actuated assembly to the handle, relative to the handle pivot axis, and apparatus for selectively supplying fluid under pressure to opposite ends of the fluid actuated assemblies to effect an extension and retraction of the rods of the fluid actuated assemblies to correspondingly effect a pivotal movement of the handle about the handle pivot axis.
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