GB583921A - Improvements in or relating to lifting jacks - Google Patents

Abstract

583,921. Lifting-jacks. GRIME, E. P., and FOY, W. F. June 19, 1944, No. 11654. Convention date, May 1, 1943. [Class 78 (iii)] A lifting jack is provided with a load supporting block carried by a pivotally supported arm which can be swung to an intermediate level and additional means for lifting the load to a higher level. As shown, a load-supporting block 16 is carried at the ends of triangular arms 6a, 6b pivoted at 9 on webs 4 secured to an elongated frame comprising spaced side plates 2 mounted on castor wheels 36 and having pivoted stabilizing arms 37 provided with adjustable feet 40 resting on the ground.. The arms 6a, 6b are swung upwardly from the position shown in Fig. 1 by admitting fluid from a pump 31 to a cylinder 10 the plunger 13 of which is connected to the arms 6a, 6b. To assist in maintaining the block 16 upright during its movement additional links 18 may be provided connecting the webs 4 and the block. When the arms 6a, 6b have been raised fully the load can be lifted further by admitting fluid from a pump 32 to a cylinder 23, mounted between the arms, to raise a plunger 27 which passes through a central bore in the block. The load rests on a fibre or stiff rubber pad 30 having a conical centring pin 29. During the raising of the arms 6a, 6b the reaction produced moves the frame along the ground.