GB346414A - Improvements in or relating to fluid pressure mechanism for lifting and lowering conveying trucks - Google Patents

Abstract

346,414. Engine valve-gear. FOLKES, G. E., 5, Corporation Street, Birmingham.- (Pintsch Akt.-Ges., J. ; 71, Andreasstrasse, Berlin.) Dec. 11, 1929, No. 37960. [Class 122 (ii).] In an automatically-controlled apparatus for lifting and lowering conveying trucks the pressure fluid (compressed air) employed for performing the lifting action is conducted through a slide valve 9, which is controlled by the movement of the hoisting piston 2, to a subsidiary piston 15, which actuates a slide 16 for reversing the valves of the hoisting cylinder 21. The arrangement of valves is such that the hoist reciprocates slowly and dwells at each end of the stroke, the length of dwell and the rate of reciprocation being adjusted by a valve 14, which controls the rate of flow of air into and out of the subsidiary cylinder 13, and by valves 25, 26, respectively. The inlet and outlet valves 17, 22 of the hoisting cylinder are opened by springs and closed by air pressure. In the position shown the hoist is moving upward and air pressure behind the outlet valve 22 keeps it closed while the inlet valve 17 is open. At the top of the stroke the collar 6 on the housing of the hoisting piston 2 engages the stop 7 and pulls up the slide 9, the cylinder 13 discharges to atmosphere through the valve 14, the piston 15 rises slowly, after a slight interval air pressure gets behind the inlet valve and closes it, and the pressure is released from behind the outlet valve, which opens so that the hoisting cylinder discharges through the valve 25 and the hoist descends. At the bottom of the stroke the slide 9 is pulled down whereby the valves are reversed and' hoisting begins again. The apparatus is stated to be applicable to lifting trucks bearing metal castings from the lower end of an inclined conveying truck to the higher initial part thereof.