Patent ID: 6988714

Claim:
A lift mechanism for use in manipulating trench covers, comprising: an axially extending housing; a cam located adjacent a first end of the housing, the cam being capable of moving between a first cam position and a second cam position; a latch located adjacent a second end of the housing, the latch being operatively associated with the cam and capable of rotational movement between a latch retracted position when the cam is in the first cam position and a latch actuated position when the cam is in the second cam position; whereby the lift mechanism may be inserted into or removed from a cover aperture when the latch is in the latch retracted position, and the lift mechanism may engage and support the cover when the latch is in the latch actuated position; and wherein the housing at least partially encloses an actuation piston connected to the cam, the piston being capable of limited axial movement relative to the housing between first and second piston positions, whereby when in the first piston position the cam is in the first cam position and the latch is in the latch retracted position, and in the second piston position the cam is in the second cam position and the latch is in the latch actuated position.