Abstract: A power actuator on the base section of a multisection telescoping crane boom can bridge at least one intermediate boom section to operate a biased locking pin retract mechanism employed in a system for remotely controlling the operation of a manual fly section of the telescoping boom. To enable the crane operator to know with certainty that the biased locking pin is in a fully engaged position, a visual indicator on the boom readily viewable from the crane operator's cab is directly mechanically linked to the biased locking pin and moves to the indicating position only when the locking pin is fully engaged.

Abstract: A power actuator on the base section of a multi-section telescoping crane boom can bridge at least one intermediate boom section to operate a biased locking pin retract mechanism employed in a system for remotely controlling the operation of a manual fly section of the telescoping boom. To enable the crane operator to know with certainty that the biased locking pin is in a fully engaged position, a visual indicator on the boom readily viewable from the crane operator's cab is directly mechanically linked to the biased locking pin and moves to the indicating position only when the locking pin is fully engaged.

Abstract: A crane boom extension or jib is held on the nose of the boom by a single fixed length self-adjusting cable loop which extends around an arcuate guide attachable at several different locations to an inclined plane mounting bracket on the jib near its outer end. The mere repositioning of the guide on the inclined plane mounting bracket allows the jib to assume several different angularly offset positions relative to the axis of the boom without other adjustments. The inclined plane mounting bracket establishes the plane in which the cable loop lies in all adjusted positions of the jib. The arrangement is convenient, safe and simplified.

Abstract: A multi-section hydraulically operated telescoping crane boom includes a manual fly section (23) which may be safely extended and retracted, securely latched in the extended position and pin locked by remote operation of a biased hydraulically powered latching plunger (33) and a biased cooperative hydraulically powered locking pin (52) both embodied in a static hydraulic circuit which includes in one form a pressure fluid circuit safety interlock portion (FIG. 4) with a pressure-responsive indicator (123) to indicate when the latching plunger (33) is engaged (48), and in another form an electrical switch circuit safety interlock portion (FIG. 7) controlling the hydraulic circuit, with an electric switch (131) operated indicator (159) to indicate when the latching plunger (33) is engaged (48). The safety interlock portions of both circuits for the cooperative latching plunger (33) and locking pin (52) prevent their operation in improper sequence so one is engaged at all times before the other is disengaged.

Abstract: A side stowable swing-around boom extension is pinned on the nose of a telescoping crane boom in a first use position nearly coaxial with the center line of the boom but tilted or offset therefrom at a small angle. Two larger angularly offset use positions of the boom extension are obtained with convenience and with complete safety while the crane boom and boom extension are at a near ground level position. Two slotted tension links are connected between the upper side of the boom extension and the boom nose and are allowed to support the boom extension in either of two major offset use positions automatically as the crane boom is elevated from the near ground level position. In such operation, the boom extension is allowed to rotate around the axis of its lower side pivotal connection with the boom nose while its upper side connection with the nose is released. The lower side connection is biased toward a position corresponding to the nearly coaxial use position of the boom extension.

Abstract: A multi-section hydraulically operated telescoping crane boom includes a manual fly section which may be safely extended and retracted, securely latched in the extended position and pin locked by remote operation of a biased hydraulically powered latching plunger and a biased cooperative hydraulically powered locking pin both embodied in a static pressure hydraulic circuit which includes a pressure-responsive indicator to indicate when the latching plunger is engaged. The circuit also includes safety interlocks for the cooperative latching plunger and locking pin preventing their operation in improper sequence.