GB372309A - Improvements in or relating to hydraulic jacking systems for motor vehicles - Google Patents

Abstract

372,309. Jacking apparatus on motor vehicles. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.-(Auto Electric Hydraulic Jack Co., Ltd. ; Tennyson Street, Napier, New Zealand.) Jan. 19, 1931, No. 1757. [Class 79 (iii).] Relates to hydraulic jacking systems on motor vehicles of the kind wherein jacks located adjacent to the respective wheels are selectively operated by fluid conveyed from a reservoir to a distributing valve chamber by a pump operated by the electric-starter motor, and comprises improvements in the form of pump and in the distributing valve arrangement. The pump, Figs. 3 and 4, comprises a, spring- returned plunger 17 driven by a cam or eccentric 14 on the end of the starter-motor spindle 13 and operating in a cylindrical chamber 10 with inlet and outlet valves 15, 16 drawing fluid from a reservoir by means of a pipe F and conveying it to the valve chamber through a pipe J. The pump cylinder 10 extends radially from a circular casing 11 which is open on one side and formed with a flange 12 for attachment to the end of the motor casing A to enclose the spindle end and cam. To prevent over-actuation of the jacks, the delivery end of the pump chamber communicates with an enlarged cylindrical chamber 19 closed at its outer end and containing a piston 20 forming an air cushion which, in the event of the development of excess pressure, is compressed until the resistance is sufficient to stop the motor. The distributing valve arrangement, Figs. 6 and 8, comprises a casting having four tubular arms 21 radiating from a centre, the connection J from the pump entering the extremity of one of the arms. Pipe connections G to the respective jacks lead from the sides of the arms, and a return connection to the reservoir from the centre. The pipe connections are made to nipples 22 by means of screwed unions 24a, the openings into the chamber serving as valve seatings adapted to be closed by ball members 25 carried by the ends of screwed operating spindles 23 mounted in sleeves 24 with packing glands 26 threaded into the opposite sides of the arms. The heads 27 of the spindles 23 may be formed as indicator knobs. Any. individual jack is extended by opening the appropriate valve 25, the fluid being locked therein by reclosing the valve. To retract any jack it is placed in communication with the reservoir by opening the central valve.