| 摘要 |
A lifting apparatus includes a lift arm for carrying a platform or cradle and is pivotally attached to a base for movement between lowered and raised positions. A crank arm is pivotal with the base and a connector arm is pivotal with the lift arm. The crank arm and connector arm are pivotally connected to each other for rotation about a common pivot axis. Rotation of the crank arm by an actuator moves the crank arm and connector arm combination through a top dead center alignment a lowered over center alignment with the lift arm movable from the lowered position to the raised position during operating positions of the apparatus, and to a raised over center alignments with limited movement of the lift arm in the raised position for providing a locking position of the apparatus thus eliminating a need for typical additional locking mechanism.
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