GB642698A - Improvements in or relating to devices for moving rail vehicles - Google Patents

Abstract

642,698. Lifting-jacks. WESTON WORKS (BIRMINGHAM), Ltd., PEARSON, D. A., BIRMINGHAM SMALL ARMS CO., Ltd., and FLETCHER, J. June 5, 1948, No. 15240. [Class 78 (iii)] [Also in Groups XXXI and XXXII] A vehicle mover having a frame with handlebars and one or more supporting wheels and a hydraulic jack which during operation is automatically controlled to maintain the lifting head in contact with, and to exert a substantially constant lift on, the vehicle. The vehicle 1 comprises two side-plates 2, a front wheel 3 and a rear wheel 4 and handlebars 5. An engine 6 mounted on the frame drives the rear wheel 4 through a gear-box 7, a sprocket 8, and chain and chainwheel 9, 10. A lifting head 14 is mounted on two side strips 13 which move between two plates 11 mounted on the side-plates 2. A hydraulic jack 19 is supported between the plates 11 and its ram 20 engages the head 14. The jack is connected to a pump unit 21 and has a shaft 22 with a sprocket 24 driven by a chain 25 from the sprocket 26 on the engine shaft. An eccentric 27 on the shaft 22 operates two opposed pistons 28 whereby liquid is drawn from the sump 29 through inlet 30 past non-return valves 31, 32 into a duct 33 to passage 34 to raise the jack. A duct 36 also connects with the tube 33 and has an enlarged part 37 and a seating for a ball-valve 39 and side holes connecting with the sump. A pushrod 41 presses on the ball and has a peg 42 passing through a hole in a leaf-spring 43. The height of the leaf-spring is adjustable by an eccentric to provide for wear. A plunger 56 is mounted in a block 55 on the top wall of the sump and rests on the spring. A lever 57 pivoted to the block has a cam 60 with a flat 59 bearing on the plunger 56. The lever is rotated by a cable 61 from the handlebars against the action of a compression spring 62. Operation of cable 61 rotates the lever 57 to press the piston 56 downwards on the leaf-spring 43 and so move the push-rod 41 on to the ballvalve 39. When there is clearance between the plunger and the flat 59, operation of the pump allows fluid to pass the ball-valve 39 and to return to the sump through the side holes without raising the jack. Further rotation of the lever 57 and cam 60 allows the jack to be operated. The ball-valve acts as a relief valve and when the jack is lowered as a release valve, the cam being then rotated until the flat is opposite the phmger 56 when the fluid can pass the ball-valve and return to the sump. Separate relief and release valves may be incorporated.