GB512486A - Improvements in or relating to lifting jacks - Google Patents

Abstract

512,486. Lifting jacks. LAKE & ELLIOT, Ltd., and BROOKES, W. March 4, 1938, No. 6855. [Class 78 (iii)] A lifting jack 2, mounted on an auxiliary or sub-base 6 by a centrally arranged spherical or part spherical joint 3 is also connected to the sub-base by means capable of supporting the jack in either an angular or upright position. In the illustrated forms, springs or dashpot devices acting on a number of rods 7 are arranged around and slidably carried by the jack, the ends thereof being connected to the base by spherical or like connections 8. As shown in Fig. 1, the spring 15 acts in compression between loose sleeves 11, 12 mounted on the rod between the ball 8 and an end stop 20, flanges 13, 14 on the sleeves normally engaging the walls 16, 17 of a housing 18 secured to the jack. The ball 8 engages a base member 9 having a part-cylindrical channel 10 disposed radially to the central joint 3. In a modification, the rod 7 carries a pair of compression springs acting on either side of a central abutment in the side of the jack, being enclosed by a housing. Stops 21 may be provided on the jack which, by engagement with the base limit the degree of tilting. As shown in Fig. 5, wherein the central seating is provided by a hemispherical boss 24 on the base, screws 25 may be provided to secure the jack rigidly to the base when desired. In the dashpot arrangement shown in Fig. 8, the upper end of the rod 7 is provided with a piston 30 operating in a cylinder 31 containing oil or other fluid, the opposite ends of the cylinder being in communication through a passage 37 and one-way valves 32, 34.