Abstract: A lifting device which includes a frame and an elongated boom having a lower end pivotally connected to the frame along a pivot axis. The lower end of the boom has a counterweight connected thereto offset from the pivot axis. The counterweight has a center of gravity which is movable with respect to the pivot axis of the boom. The counterweight can be freely pivotal, fixed, or partially fixed with respect to the boom. When linkage is provided between the counterweight and the boom, the counterweight can be rolled or tilted so as to move the counterweight center of gravity with respect to the pivot axis of the boom.

Abstract: A lifting device which includes a frame and an elongated boom having a lower end pivotally connected to the frame along a pivot axis. The lower end of the boom has a counterweight connected thereto offset from the pivot axis. The counterweight has a center of gravity which is movable with respect to the pivot axis of the boom. The counterweight can be freely pivotal, fixed, or partially fixed with respect to the boom. When linkage is provided between the counterweight and the boom, the counterweight can be rolled or tilted so as to move the counterweight center of gravity with respect to the pivot axis of the boom.

Abstract: A lifting device which includes a frame and an elongated boom having a lower end pivotally connected to the frame along a pivot axis. The lower end of the boom has a counterweight connected thereto offset from the pivot axis. The counterweight has a center of gravity which is movable with respect to the pivot axis of the boom. The counterweight can be freely pivotal, fixed, or partially fixed with respect to the boom. When linkage is provided between the counterweight and the boom, the counterweight can be rolled or tilted so as to move the counterweight center of gravity with respect to the pivot axis of the boom.

Abstract: A lifting device which includes a frame and an elongated boom having a lower end pivotally connected to the frame along a pivot axis. The lower end of the boom has a counterweight connected thereto offset from the pivot axis. The counterweight has a center of gravity which is movable with respect to the pivot axis of the boom. The counterweight can be freely pivotal, fixed, or partially fixed with respect to the boom. When linkage is provided between the counterweight and the boom, the counterweight can be rolled or tilted so as to move the counterweight center of gravity with respect to the pivot axis of the boom.

Abstract: A lifting device which includes a frame and an elongated boom having a lower end pivotally connected to the frame along a pivot axis. The lower end of the boom has a counterweight connected thereto offset from the pivot axis. The counterweight has a center of gravity which is movable with respect to the pivot axis of the boom. The counterweight can be freely pivotal, fixed, or partially fixed with respect to the boom. When linkage is provided between the counterweight and the boom, the counterweight can be rolled or tilted so as to move the counterweight center of gravity with respect to the pivot axis of the boom.

Abstract: An articulated telescopic boom assembly for a lifting device includes a first elongated boom having a central longitudinal axis and an opening in one end; a second elongated boom having a first end normally telescopically received by and extensible from the first boom opening, the first end having at least one elongated pivot guide slot therein having a central longitudinal axis with an open end remote from the first end and a closed end proximate to the first end; and a slide-through knuckle having a housing with an opening therein for receiving the second boom during extension and retraction thereof. The housing is pivotally connected to the first boom by a pair of opposing elongated pins which define a pivot axis. The central longitudinal axis of the pivot guide slot is offset from and perpendicular to the pivot axis such that when the closed end of the guide slot is registered with the pivot pins, the second boom is pivotable.

Abstract: A scissors lift apparatus has three scissor units for supporting heavy loads. A central scissor unit has its arms located inwardly of the immediately lower and upper scissor units, and folds into the upper and lower scissor units for storage within a chamber in a mobiled chassis. The scissor arms of the upper and lower scissor units includes rectangular box beams with a greater vertical than horizontal dimension. Hydraulic cylinders are located within and coupled to the opposite two arms of the center scissor unit to expand and collapse the same. The mobile chassis has front steering wheels mounted with hydraulic powered-caster-type wheel drive and steering apparatus. The steering king pin is laterally offset from the vertical plane through the center of wheel. A dual fail safe braking unit on the trailing wheels has an applied hydraulic cylinder unit including a floating cylinder with a single spring applied piston and rod which is supported in a fixed journal and connected to one wheel.

Abstract: A work platform frame is connected to a vertically disposed pin fixed to one end of a boom. An idler bracket is also pivotally mounted on the pin and has outwardly extending first and second idler arms, which are offset, with respect to each other, by between 90.degree. and 120.degree.. A first hydraulic assembly is connected between the first idler arm and the work platform frame. A second hydraulic assembly is connected between the second idler arm and the boom. Hydraulic fluid is selectively applied to the first and second hydraulic assemblies to cause rotation of the work platform about the pin through an arc of 180.degree., each hydraulic assembly and its associated idler arm accounting for 90.degree. of such rotation.

Abstract: A self-propelled rotatable hydraulic lift having a body with an extensible boom pivotally attached to the upper rear portion of a counterweight and terminating in a self-leveling workman's platform. Remote lift controls are provided at the platform by means of control lines contained in flexible conduits within the boom. The center of gravity of the counterweight is located between the pivotal connection of the boom and the axis of rotation of the boom to provide both improved stability with respect to back tipping when the boom is extended vertically and a smaller rotational diameter for the lift body.

Abstract: A self-propelled rotatable hydraulic lift having a body with an extensible boom pivotally attached to the upper rear portion of a counterweight and terminating in a self-leveling workman's platform. Remote lift controls are provided at the platform by means of control lines contained in flexible conduits within the boom. The center of gravity of the counterweight is located between the pivotal connection of the boom and the axis of rotation of the boom to provide both improved stability with respect to back tipping when the boom is extended vertically and a smaller rotational diameter for the lift body.