Lifting and positioning device

Abstract

A device for lifting and positioning building materials at different heights and angles. For example, positioning a sheet of drywall or plywood to be fastened to a ceiling or wall, or subsequently a container of materials such as drywall joint compound for finishing the fastened sheets. The lifting and positioning device comprises a platform assembly upon which to place material to be lifted and positioned. The platform assembly can be pivoted and fixed at any desired angle between horizontal and vertical (0 to 90 degrees) by an indexing arrangement. The platform assembly is pivotally connected to lift arm links. The lift arm links are pivotally connected to a lift arm assembly. The lift arm assembly is pivotally connected to a mast support assembly. The lift arm links, lift arm assembly and mast support assembly form a parallelogram. The platform assembly is raised and lowered by a floor jack placed upon a jack support platform. As the floor jack is actuated, the jack saddle moves upward, pushing on a push link connected to the lift arm assembly causing the platform assembly to raise. Because of the parallelogram arrangement, the platform assembly maintains almost the same angle throughout the lifting range, from the maximum lowered position to the maximum raised position. This is important so that the building materials do not fall off the platform assembly as they are raised or lowered. When the sheet is raised and near its fastening position, the sheet is self-leveled to fit flat against the fastening members. Self-leveling is accomplished by allowing limited freedom of movement of the platform assembly through an indexing arrangement.

Dependencies are inferred from the claim text.