GB190602183A - Improvements relating to Screw Lifting Jacks for Motor Car and other Services. - Google Patents

Abstract

2183. Lucas, H., and Taft, E. Jan. 29. Lifting-jacks for raising motor-cars &c. are provided with means for disengaging the nuts to enable the lifting-screws to be raised or lowered when the jacks are being adjusted roughly to the height of the work. Fig. 4 shows a ratchet-operated screw jack with the buttress - threaded lifting- screw engaged bythe two segments of a split nut e,. which is seated on the inner coned surface of the rotable ratchet-head b. Inwardlyprojecting pegs f on the ratchet head separate the two halves of the split nut on either side, and provide a positive driving- connexion between the nut and ratchet head for operating the lifting- screw. A cap a, having pegs g extending between the halves of the split nut, is secured rotatably to the ratchet-head by means of pins c loosely engaging an annular recess in the head. On the application of a direct lifting motion to the screw, the halves of the split nut are moved up the inclined seating against the cap, thus being separated and allowing the screw to pass through. To lower the screw quickly, the cap a is rotated relatively to the ratchet-head, when the pegs g force the segments of the nut apart, and thus raise it in the seating to allow the screw to fall by its own weight. To ensure that the segments of the nut always return to the normal position in engagement with the lifting-screw, suitable springs are provided between the cap and the upper surfaces of the segments of the nut.