Abstract: A double jib slewing pedestal crane includes a main jib and a secondary jib, and a secondary jib positioning device to support and position the secondary jib with respect to the main jib and actuate the pivotal movement of the secondary jib. The secondary jib positioning device includes a secondary jib positioning cable; a spoke structure fixed to the secondary jib and extending radially outward; a tension chain connected at one end to the secondary jib positioning cable and at the other end to the secondary jib and/or to the spoke structure, wherein the spoke structure is adapted to support the tension chain.

Abstract: A trolley control system for a gantry crane having a multiple trolley arrangement such as a first and second trolley. The control system including a trolley beam connected to the gantry crane with a first and second drive device connected to the trolley beam. The first drive device is powered by a first drive system while the second drive device can be powered by either the first drive system or the second drive system. A first trolley is connected to the first drive device while a second trolley is connected to the second drive device.

Abstract: A drum drive assembly for cranes which use a load hoist line reeled onto a load hoist line drum to lift loads allows the load hoist line drum to be disconnected from the drum drive motor to permit the load hoist line drum to rotate independent of the drum drive motor. The drum drive assembly comprises one or more motors for rotating the load hoist line drum to either pay out or reel in the load hoist line; a brake for slowing, stopping or preventing the rotation of the load hoist line drum; and a jaw clutch which may be disengaged to permit the load hoist line drum to rotate independently of the motor.

Abstract: A control for a crane having a plurality of pressure-activated clutches with a control panel in the cab on a swingable upper works. A lightweight portable control panel is connected by an umbilical cord to the rotating joint and a switch selectively connects either the portable panel or the cab panel to an amplifier. An encoder in each panel provide redundant control signals to the amplifier which amplifies the signal with less noise and passes the amplified signal to a decoder which selects the proper current source to activate a solenoid-actuated hydraulic valve to modulate hydraulic pressure to the clutch selected by operation of a control lever on the selected one of the two panels.