GB664686A - Improvements in or relating to hoists - Google Patents

Abstract

664,686. Equalizing tensions. HOUILLERES DU BASSIN DU NORD ET DU PAS-DECALAIS. Nov. 24, 1948. [Nov. 29, 1947] No. 30569/48. Class 78 (ii). A hoist, Fig. 2, of the type in which a cage 34 or the like is supported by a plurality of ropes 29, 32, each of which ropes passes over a headsheave or pulley 13, 16 and is connected at one of its extremities to said cage and at its other extremity to a common winch, is characterised in that the hoist comprises equalizing devices 17, 20 which equalize the strains in the different ropes connected to said cage and the like and which act on the ropes at points disposed along said ropes between the cages and the common winch. Fig. 2. Cages 33 and 34 are each elevated by twin ropes, the pairs of ropes 29 and 30, and 52 and 31, each forming the two ends of a single rope passing to and round and driven by the driving drum (not shown). The ropes pass over pulleys 16, 13, 14, 15 mounted in pulley blocks 20,17,18,19 respectively. Pulley blocks 20 and 17 are loosely linked by pivoted rods 21 and 22 and these latter are pivoted about axes 23 and 24 respectively. Similarly, blocks 18 and 19 are linked and pivoted about axes 27 and 28. Hence if the tension of rope 29 is greater than that of rope 32 blocks 17 and 20 pivot about axes 23 and 24 and block 17 descends and block 20 rises so as to equalize the tensions. Likewise for blocks 18 and 19. The axes 23 and 24 may be coaxial and in a horizontal plane or they may be coaxial and parallel to the axes of the blocks, the blocks may have their movements changed by dash pots, or springs, or by friction ; and the pairs of ropes 29 and 32, 30 and 31 may be respectively tied to the ends of two horizontal rods, each of which is pivoted at its centre by a vertical rod to the respective cages 34 and 33. Fig. 4. Modification of Fig. 2. The blocks are formed into rigidly-connected compound blocks 35 and 36, and these two compound blocks 35 and 36 are pivotally connected by rods 37 and 38 rotatable about axes 39 and 40 respectively. Fig. 8. Modification of Fig. 4. The rigidlyconnected pairs 71 and 72 are guided for relative longitudinal movement by wheels 76 moving along guides 77 and the downward movement of 71 is caused to move 72 upwards by means of racks 73 and 74 coacting with rack wheel 75.