GB707409A - A lifting device - Google Patents

Abstract

707,409. Lifting devices for hoisting stacks of sheets. JAEGER MACHINE CO. May 30, 1951 [June 2, 1950], No. 12701/51. Class 78 (4) A releasable looking device prevents the normal gravity closure of the tongs of a device for lifting a pile P (Fig. 5) of sheet or plate material when the device is raised by a crane. In the device illustrated the tongs comprise loadgripping plates 32 welded at each end to the flanges of the outer vertical angle-section links 24 of parallelogram linkages 20, 22 extending from central bars 19. The spindles 23, 25, 26, 29 forming pivots of the linkages extend the full length of the device (see also Fig. 4) which is strengthened by the provision, midway between the end linkages, of links corresponding to the links 20 and 24 of the end linkages. Links 27 connected at 28 by pins working in slots in the bars 19 ensure conjoint movement of the parallelogram linkages. The device is normally held in its open condition by bars 37 (Fig. 4) secured at each end of one of the spindles 29 and formed with ratchet teeth 56 engaging the other spindle 29 and so shaped as to permit the device to expand but not to close. The bars 37 are raised by cams 41 fast On the spindle 29 and engaging a ledge 42 on the bar 37, to allow the device to close on a load, when a cable 48 anchored to a grooved sector 45 carried on a crank 46 from the spindle is pulled against the force of a counterweight 43. The cable 48 is guided over a roller 50 on the end of an arm 51 formed with a notch 54 which takes over one spindle 29 and welded to a rod 52 which slides in a block 53 secured to the other spindle 29. Compression spring devices 57 secured to the parallelogram linkages assist the automatic opening of the device when it is lowered onto a supporting surface. A stack of sheets P (Fig. 5) may be supported on the lips 34 of angle irons 33 carried by the plates 32 and provided with rollers 35 for engaging the lower surface of the stack. T-section stacking guides 62, for facilitating the positioning of one stack of sheets vertically above another, slide in housings 63 secured to one of the plates 32 and are retained in their housings by caps 64. Lugs 65 protect the upper ends of the housings 63. Stops 66 limit the extent by which the device may be lowered onto a stack.