Importance

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Abstract

An elevating device for a workman's platform in which a single lift cylinder is utilized, positioned below the lift arms when the arms are in their fully retracted or lowered position. A piston of the cylinder is operatively connected to one of the lift arms, with the opposite end of the cylinder being operatively connected to one end of a pivot arm assembly which is mounted for rotation about a fixed axis on the base. The opposite end of the pivot arm assembly carries a roller which is adapted to engage the cam surface of a cam plate mounted on the same lift arm. When the lift cylinder is actuated, the piston functions to raise the lift arm at its connection point to the piston, simultaneously with the rotation of the pivot arm assembly and the consequent lifting of the cam roller against the cam surface thereby elevating the arm at that location as well. This lifting at points on either side of a central connecting point of the lift arm reduces the initial lifting force required thereby permitting a single lift cylinder to be employed.

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First Claim