GB1133315A - Jacking apparatus for use in building - Google Patents

Abstract

1,133,315. Step-by-step lifting jacks. BRITISH LIFT SLAB Ltd. 1 Nov., 1967 [2 Nov., 1966], No. 49142/66. Heading B8J. [Also in Division F2] Apparatus for use in carrying out building operations in which roof and floor slabs are fabricated at or adjacent to ground level and are subsequently hoisted to the positions they are to occupy in the finished building comprises a jack 12 mounted on a preformed vertical column 11 with a first cross-head 13 disposed below the jack 12 and a second crosshead 14 engaged by the upper part of the jack 12. A floor slab 10 cast about a plurality of the columns 11 is connected to each of the associated hoisting devices by a pair of screw-threaded lifting rods 16. Follow-up nuts 18, 19 are provided for conventional step-by-step lifting of the slab 10. The cross-bars 13, 14 have apertures 15 large enough to permit the passage of the rods 16 and any couplers 17 used for connecting two rods 16 in end-to-end relationship. The nuts 18, 19 are split or hinged and are carried in nut support members 20, 21 of tubular form which are formed internally with a recess 22 at each end to receive the nut 18 or 19 so as to prevent it opening and arranged so that rotation of the member 20, 21 rotates the nut 18, 19, respectively. When lifting has proceeded to the stage where a coupler 17 has passed into the interior of member 20 a further lifting stroke of the jack 12 is effected, but before the retraction stroke, and while the slab 10 is supported by nut 19 and member 21, member 20 and its nut 18 are rotated until the nut 18 has moved sufficiently far upwards for the member 20 to be lowered so as to disengage from the nut 18 which can then be disengaged from the rod 16. The member 20 can then again be raised and the nut 18 reengaged with the rod 16 below the coupler 17 and received in the lower recess 22 by lowering the member 20. In the embodiment shown in Fig. 3 a nut 24 of split or hinged construction has an integral extension 23, opening of the nut 24 in use being prevented by a collar or ring 25. A similar ring or collar may be used at the end of the extension 23. In use lifting proceeds until a coupler 26 passes into the interior of the extension 23. The collar 25 is then disengaged from the nut 24 so that the nut 24 can be disengaged from the lifting rod. The nut 24 is then. turned upside down so that it can be re-engaged under the coupler 26 whereupon lifting may proceed.