Patent GB-779597-A (GB)
Title: Improvements in or relating to motor vehicles
IPC: B60G17/08
Filed: 1955-12-08
Abstract: 779,597. Road-vehicle spring-suspensions; hydraulic shock absorbers. FORD MOTOR CO., Ltd. Dec. 8, 1955 [Dec. 31, 1954], No. 35283/55. Classes 108(2) and 108(3). A combined hydraulic shock absorber and telescopic control member for a road wheel 14, comprises an upper cylinder 44 telescopically received within a lower cylinder 40, a central tube 54 rigid with the cylinder 40, an annular piston 56 carried by the lower end of the cylinder 44 and reciprocable within the annular chamber 60 between the cylinder 40 and the tube 54, the latter having an opening or openings 62 beneath the normal position of the piston 56 to connect the chamber 60 and the interior of the tube 54, and a valve block 64 carried by the tube 54 at its upper end and reciprocable within the upper cylinder 44, dividing the latter into an annular chamber 84 beneath the block 64, and a reservoir 106 above the valve body 64 and having a pair of restricted passageways 90 establishing restricted communication respectively between the reservoir 106 and the chamber 84, and between the reservoir 106 and the central tube 54. The road wheel 14 is carried by a spindle 24 rigid with the lower cylinder 40. A suspension arm 18 pivotally mounted on the frame at 16 is connected by a ball joint 20 to the spindle 24. A vertical flange 28 rigid with the arm 18 acts through a rubber block 30 upon a suspension coil spring 34. The upper tube 44 is connected by a rubber mount 48 to the vehicle frame at 26. The valve block 64 comprises a pair of control valves 70, 72. The valve 70 controls flow between the reservoir 106 and the annular space 84. The valve 72 controls flow between the reservoir 106 and the interior of the tube 54. A one-way check valve 74 connects the reservoir 106 with the interior of the tube 54 via a passage 120. A similar valve 76 connects the reservoir with the annular space 84 via a passage 112<SP>1</SP> which is axially disposed, but is offset from the central axis of the shock absorber so that it is in line with the space 84. The valve 70 comprises an abutment member 94 for a spring 98 which acts at its other end upon a blow-off member 88 seated over an opening 80 leading via a passage 82 to the space 84. The axial position of the abutment 94 is controlled by a plastics thermostatic member 112. The member 94 carries a needle valve 92, the position of which determines the area of flow through an orifice 90 formed in the valve 88. The construction of the valve 72 is identical with that of the valve 70. In operation, on compression, liquid is forced by the piston 56 through the openings 62 into the interior of the tube 54. It then passes through a passage 86 to the seat of the blow-off valve 88 of the valve 72. It then passes through the aperture 90, ports 124 in the member 94, ports 104 in the upper part of the housing of the valve 72, and thence into the reservoir 106. Changes in viscosity of the liquids due to changes in temperature are compensated for by the position of the needle valve 92 under the control of expansion and contraction of the thermostatic elements 112. At a predetermined pressure, the valve 88 lifts against the action of its spring 100. Liquid is drawn from the reservoir 106 through the aperture 90 of the valve 88 in the valve 70 and thence to the space 84. If necessary, further liquid is drawn from the reservoir 106 to the space 84 via the valve 76. Extreme compression is cushioned by the hydraulic stop formed by the piston 64 covering the openings 62. On extension, liquid is forced from the space 84 through the valve 70 into the reservoir 106. Liquid is drawn from the reservoir 106 via the valve 72 into the interior of the tube 54. Liquid may also pass from the reservoir 106 to the interior of the tube 54 via the valve 74.