Patent GB-191214038-A (GB)
Title: Improvements in shock absorbers for motor cars and other vehicles
IPC: F16F9/14
Filed: 1912-06-17
Granted: 1912-10-10
Abstract: 14,038. Derihon, M. June 17. Dash - pots.-Relates to shock-absorbers interposed between the plate springs and the body of vehicles, and acting on the return movement only, and consists in a device which permits free movement in either direction from the normal position of the suspension spring relative to the frame, but opposes a constant resistance to the return movement in either direction to the normal position. In the form shown in Fig. 2, the movements of the suspension spring relative to the frame are communicated by a lever to a shaft b turning in a cylinder a, fixed to the frame; this cylinder is filled with oil, and is provided with a fixed vane g. A vane d, e fixed to the shaft b is thereby caused to rotate in the oil, but owing to the provision of valves i in the vanes, and also to the greater diameter of the lower half of the cylinder a, this rotation is unretarded in whichever direction it occurs. On the return motion, from either of the positions d, e, or d<2>, e<2>, the valve i in the upper half of the cylinder a closes and the oil is compelled to return through a restricted passage k adjustable by means of the screw l, and a constant resistance is thereby opposed to the return motion. In the modification shown in Fig. 5, the lever rotates a shaft s in the brake cylinder a on which is keyed a double pinion r, each part of which has toothed and smooth segments adapted respectively to engage similar wheels p, q fived respectively to the vane d, e, and to the vane g carrying the valve i. If the shaft s rotates in one direction, the wheel p is rotated and the wheel q remains stationary, so that the vane d, e moves towards the dotted line position d, e. This motion, owing to the opening of the valve i in the stationary vane g is unretarded; but during the return motion, the valve i closes, and the oil is compelled to pass from one side of the vane g to the other through a restricted passage similar to that shown in Fig. 2, or formed in the vane g. A similar effect is produced if the shaft s rotates in the opposite sense, but in this case the vane d, e remains stationary and the vane g moves. In the form shown in Fig. 11, a double piston d, e connected to the frame moves in a cylinder a connected to the axle. A fixed partition g is interposed between the pistons d, e, and is provided with a duct k of adjustable width. The end compartments z of the cylinder a communicate with each other through the rod f, which is partly hollow, and also through an annular space between the cylinder a and an outer casing m. The pistons have valve openings i, governed by a double valve c, and the cylinder a is of larger diameter than the pistons d, e at that part included between them when they are in their normal positions. If the rod f moves downwards in the cylinder, its motion is unretarded owing to the opening of the valve in the piston d, and the greater diameter of the cylinder in the region of the partition g. On the return motion, the valve in the piston d closes, and the oil is compelled to pass through the duct k, thereby retarding the motion. A similar effect is produced by an upward motion of the rod f.