GB917137A - Travelling crane for precise operation - Google Patents

Abstract

917,137. Handling radioactive material. COMMISSARIAT A L'ENERGIE ATOMIQUE. May 1, 1959 [May 6, 1958], No. 14936/59. Class 39 (4). [Also in Group XXX] A treating shop for radioactive materials contained in baskets 2 includes a garage A, coffer B and treating bay C and a crane having a carriage 8 running on a track 10. Hooks 31 on the crane hoist 15 permit lifting of a basket 2 from a container 4 on a carriage 3 through a hatch 5 and lowering the basket into a tub 1. The tubs 1 are introduced into the shop by the crane through a hatch E. To permit exact centring of the crane hooks 31 above the hatch 5 and tubs 1 fixed guides 17 are provided above those positions, the guides forming vertical guide-ways for the ends 20 of a transverse member 19 forming part of the crane hoist 15. The hoist comprises an upper section 15A comprising the member 19 carrying two pulleys 23, 24 and a lower section 15B comprising a plate 25 supporting a pair of pulleys 27 and the hooks 31. The hoist cable 40 is fixed at end 41 and passes in succession over one of two pulleys 42 mounted on carriage 8, over one of the pulleys 27, then over pulley 23, over the other pulley 27 and the other pulley 42, then over a pulley 43 to a hoist winch 44. Normally the cable 40 holds the lower section 15B so that conical members 29 thereon are located on conical members 30 on the section 15A and the transverse member 19 is guided in guides 16 fixed to the carriage 8. The guides 16 are similar to the fixed guides 17 and form upper extensions of the guides 17 when the carriage 8 is in a lifting position. When the hoist is lowered by the winch 44 the member 19 moves from the guides 16 into guides 17 and eventually the member 19 is arrested by stops 18 on the guides 17 whereby the upper section 15A of the hoist stops but the lower section 15B continues to move at half speed on account of the pulley arrangement 23, 27. The section 15B is thus free to be precisely aligned with a basket 2 or tub 1 as the hooks 31 enter, guide fins 39 serving to effect the alignment. The hooks 31 are actuated to engage an inner flange 7 of a basket by a cable 45 secured at end 46 and wound similarly to the cable 40 over pulleys 47 on the carriage, pulley 24 and a pair of pulleys 34 on the hoist section 15B, the cable 45 then passing over pulleys 48, 49, 51 to the hoist 44. The pulley 48 supports a counterweight 50 and the pulley 51 is carried by a jack 52. The pulleys 34 are mounted for limited vertical movement by a rod 36 slidable in the plate 25, the lower end of the rod carrying a counterweight 35 which is heavier than the weight 50. Thus during hoisting the cables 40, 45 act similarly and there is no vertical movement of the rod 36 relatively to the plate 25; however to actuate the hooks the jack 52 is operated so that weight 50 is arrested in its upward movement by the stop 54 and weight 35 is moved whereby levers 32 having their ends freely mounted between the weight 35 and a plate 38 on the rod 36 operate the hooks 31. A further cable 11 and winch 14 drives the carriage 8. The control desk F has means giving an indication of the operations proceeding in the treating shop and relays actuated by the crane movements may permit automatic operation of the crane.