GB391777A - Improvements in lifting gear - Google Patents

Abstract

391,777. Loadhandling machines. ELECTRICARS, Ltd., TREECE, J. W., and JONES, C. E., 45, Lawley Street, Bir. mingham. Oct. 26, 1931, No. 29655. [Class 78 (iii).] - A load-handling machine comprises a truck frame, a supporting structure pivoted on said frame about a vertical axis, said structure having an arm extending longitudinally of the truck, an extensible jib pivoted to the projecting end of said arm, and hydraulic means for raising and lowering the jib and for adjusting the length thereof. As shown in Fig. 1, the jib, comprising telescopic channel members 19, 21, is pivoted on an arm 17 projecting from a structure 16 on a turntable 8 carried by a self-propelling truck 2, and is extended by a piston 31 operating in a cylinder 33 and raised by a piston 26 operating in a cylinder 27. Fluid is supplied to these cylinders by a pump driven by an electric motor, and the pressure is controlled by valves 40, 39, Fig. 6, which are arranged as shown diagrammatically in Fig. 10 and are selectively actuated by a lever 55, Fig. 8. This lever is mounted on a ball joint 56 and is connected by ball joints 61, 62, Figs. 5 and 8, and links 65, 68, to levers 66, 63, on the valve spindles 67, 64, respectively. The links 65, 68 are ball-jointed at both ends so that when the lever 55 is swung vertically, the valve 39 is actuated through the link 65 but the valve 40 remains stationary, the link 68 swinging about its ball joints. The valve 40 is actuated when the lever 55 is swung horizontally. When either of the levers 63, 66 is operated a cam 69 thereon engages a roller 70 and actuates a rod 74 to close a switch controlling the pump motor, the switch being reopened when the lever 55 is returned to its neutral position. The rod 74 may operate a clutch when motive power other than an electric motor is employed. The relative movement of the jib members 19, 21 is limited by stops 91, Fig. 1, on the member 21 which, in the limiting positions, engage a cam 92 on a spindle carrying a crank-arm 93 connected to the valve lever 63 by a rod 94, whilst the pivoting movement of of the jib is limited by stops 95, 96, which engage an arm 97 of a lever 98 connected to the valve lever 66. Either or both of the axles of the truck may be unsprung so that the wheels and transmission gear serve as a balance weight to prevent tilting of the truck under load. A block 103, moving in guides 104 and connected to the jib by a chain 105, is provided with a roller 106 which engages a U-shaped guide 107 to limit movement of the frame 16 about its vertical pivot.