Patent GB-1251601-A (GB)
IPC: B62B3/06
Filed: 1969-01-01
Abstract: 1,251,601. Lifting devices; low-lift trucks. C. J. P. LEBRE. 1 Jan., 1969 [2 Jan., 1968; 28 Feb., 1968], No. 161/69. Headings B8H and B8J. A lifting device, Figs. 1, 2, comprises a U-shaped frame consisting of two L-shaped members, one comprising a hollow cross member 1 and a side member 2, the other a cross member 3 slidably mounted in the cross member 1, and a side member 4 similar to side member 2. A central tubular sleeve 5 permits free sliding movements of the members 1, 3, the spacing of members 2, 4 being adjusted by rotating a screw rod 7 engaging an internally screw-threaded tube 8. The side members 2, 4 are hollow and have telescopically mounted therein corresponding arms 20. The device can thus be adjusted to suit the dimensions of a load to be lifted. Each side member 2, 4 carries, adjacent the junction with the relevant cross member 1, 3, an inner strap 10 having pivotally mounted about a vertical axis a rotary elliptic cam 11 with a flat bottom face and a helical cam face 12, Fig. 4, connecting the edge 13 a floor level to a wider flat face located at a higher level. At the end of each arm 20 is pivotally mounted on a pin 24 a carrier wheel 27 on a pair of links 25. The links 25 have another pivot pin 28 carrying a strap 2a supporting an axle 31 of a roller 30. A hexagonal pin 32 on the strap 2a may be engaged by a spanner to pivot the strap 29 until the roller 30 engages the arm 20. Continued movement of the strap 29 will lower the wheel 27 to the floor and lift the frame of the device to a sufficient height for it to be displaced with its load. A third wheel in the form of a caster 45 with a steering bar 46 is slidingly mounted on the frame sleeve 5 and can be used to raise the frame of the device by actuating a hexagonalsectioned rod 48 carried by links 37 of parallel links 37, 38. The device is positioned around the load to be lifted with the cams 11 and auxiliary bearing plates 23 retracted under the frame. The two cams 11 are then actuated in succession resulting in the cam faces 12 being inserted under the load, rotation of about 90 degrees bringing the flat top faces 14 under the load. The rod 48 is then actuated to raise the right hand portion of the frame with respect to the caster 45. This normally results in a sufficient gap for the insertion of the auxiliary bearing plates 23 under the load. (If the gap is insufficient a block is inserted about midway between the cams 11 and plates 23 and the right hand portion of the frame lowered so that the load tilts to provide an adequate gap.) The left hand portion of the frame is then lifted on the wheels 27 by actuating the pins 32 when the load can be moved off on the wheels 27 and caster 45 is required. In the modification shown in Fig. 6, each arm 20 has a pair of uprights 60, 61 with rack teeth and slidingly carries a runner 62, 63 with a spring-loaded pawl 64, 65. The front and rear faces of the runners 62 have a pair of brackets 66, 67 with parallel tubular sleeves (68), (69), Fig. 5 (not shown), interconnected respectively by slidably mounted bars (70), (71). The device thus provides a gantry adapted to engage hollow portions of a load to be lifted. The bars (70), (71), may be raised step-by-step by a pivoted control lever 72. They may be lowered by pulling cables 77 to release the pawls 64, 65.