GB348688A - Improvements in and relating to jacking-apparatus for motor cars or other vehicles - Google Patents

Abstract

348,688. Fluidpressure operated jacks. HEDGES, A. E., Kingston, Taunton, Somerset. Feb. 14, 1930, No. 5024. [Class 78 (iii).] A jacking attachment for motor and other vehicles comprises a pivoted link or strut 6 the free end of which is connected to the rod 20 of a piston 21 operated by fluid pressure in a pivoted cylinder 17. The ends of the piston rod and link are forked and connected by a pin 8 carrying a roller 9 which may engage the ground directly or may be peripherally grooved to ride along a cam track 10 on a shoe 11 suspended by means of shaped bars 12 passing over the ends of the pin 8 and constrained by a compression spring 19 on a rod 14 connecting the end 15 of the shoe to a bracket 16 on the cylinder. The piston stroke is limited by a rod 22, passing through the end of the cylinder, where it is screwed into a part 24a forming the pivotal connection to the supporting bracket 25 on the vehicle. Fluid under pressure, supplied by a pump and controlled by a two-way cock, is conveyed to the inner end of the cylinder by a connection 44 or may be led to the outer end from a second connection 46 through a pipe 47 leading to an elbow 48. Non-return valves may be arranged within the connections 44, 46 or in association with the pump. Automatically actuated valve means are provided whereby, at each end of the stroke, that portion of the cylinder receiving the fluid under pressure is opened to the atmosphere whilst the other end is closed, preparatory to the return stroke. For this purpose, a glanded nipple 30a, at the outer end of the cylinder, -forms a stuffing box for a slidable valve member 30, which is connected, by a head 27, with a second similar valve member 31 operating in a stuffing box 33, located on the outside of the cylinder and communicating, by a pipe 45, with the inner end thereof. Axial passages in the valve members, terminating in lateral ports 38, 39, are so arranged that, on the completion of the return stroke, when a stop 41 on the piston rod engages the valve head 27, the valve members are pushed inwards as shown in Fig. 1, closing the valve 30 and opening the valve 31 in readiness for the next outward stroke, the positions being reversed when the piston, at the end of the outward stroke, engages and pushes outwards the valve member 30. The parts may be supported in the raised position, Fig. 1, by a depending plate with an upturned end engaging under a pin.