GB335539A - Improvements in or relating to steering gear for motor road vehicles - Google Patents

Abstract

335,539. Payne, M., and Clayton Dewandre Co., Ltd. June 24, 1929. Steering-gear; hydraulic and pneumatic transmission. - Comprises steering-gear in which engine suction or other fluid pressure is employed under the control of a valve connected to a lever arm, such as the drop arm 3, through the medium of a two-armed lever 5, which constitutes the sole connection between the lever arm and the member actuated thereby, and which is fulcrumed on the lever arm and connected at one end to a member 4 of the steering-gear and at the other end to the valve 12, the end connected to the valve being movable between fixed stops located adjacent the fixed fulcrum of the lever arm 3. In the construction shown the upper end of the lever 5 is formed with an eye which loosely embrace a pin 8 concentric with the pivot of the arm 3 and is provided with spring-pressed pins 9, Fig. 2, tending to keep the arm and the lever in line. The lower end of the lever is connected to the drag link 4 and also by a rod 10 to a power cylinder 11. The valve 12 controlling the cylinder 11 comprises a casing 14, Fig. 5, a central hollow plunger 20 connected by a link 13 to the lever 5 and having ground ends, and two spring loaded valves 17. In the neutral or central position shown in Fig. 5 the plunger 20 is not in contact with either of the valves 17, and the cylinder 11 is open to the atmosphere at both ends through pipes 27, grooves 18 in the valves 17, the hollow plunger, and a port 24. When the steering hand-wheel is rotated, the drop arm is moved, the lever 5 rocks slightly about its lower end and moves the plunger 20 which abuts against and opens one of the valves 17 and thus connects the corresponding end of the power cylinder to the engine induction pipe through pipe 27, valve 17, and pipe 25. The connection of that end of the cylinder to the atmosphere is cut off when the plunger abuts against the valve 17. The drag link 4 is thus operated and as soon as the drop arm comes to rest the lever 5, which has been following the drop arm, centres itself over the drop arm and the valve 12 is returned to the neutral position with the steering gear in the required position. A modified construction of valve is described in which the. member connected to the link 13 has valve faces beyond the outer ends of the valves 17. A constant-pressure vacuum valve may be provided between the induction pipe and the control valve, and, in order to enable, the servo action to be cut out when required, a valve may be provided which cuts off the device from the induction pipe and opens both ends of the power cylinder to the atmosphere. Two single-acting power cylinders may be employed instead of one double-acting cylinder. According to the Provisional Specification the steering-gear worm sector may be connected by parallel links to the drop arm, one of the links operating the valve controlling the power cylinder.