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.