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.