Patent GB-473971-A (GB)
Title: Improvements in or relating to a pneumatic shock-absorbing and suspension device
IPC: B60G17/052
Filed: 1936-04-22
Abstract: 473,971. Vehicle suspensions ; shockabsorbers. FIRESTONE TYRE & RUBBER CO., Ltd. April 22, 1936, No. 11510. Convention date, Jan. 3. [Classes 108 (ii) and 108 (iii)] A pneumatic suspension device for vehicles comprises a flexible bellows interposed between the chassis and a wheel and in communication with a compressed-air reservoir, flow of air between the bellows and reservoir being regulated by a valve controlled by means which normally engage the valve to permit unrestricted flow of air, the means being movable, under the influence of inertia, out of operative engagement with the valve so as to cut off communication between the bellows and reservoir, e.g. when the vehicle rounds a bend or stops suddenly. The valve-control means in devices on opposite sides of the vehicle may be movable similarly longitudinally of the vehicle but in opposite directions laterally of the vehicle. The suspension device shown in Figs. 1, 2 comprises parallel double-links 42, 46 and 33 pivotally connected at their outer ends to an upright member 26 on which the wheel is pivotally mounted and at their inner ends to fixtures on a transverse chassis member 22, the lower end of the bellows being secured to the top of the upright member 26 while the upper end of the bellows is secured to a housing 75 having a depending portion 78 and a longer extension 81 fastened at their lower ends to the frame member 22. Encircling the constricted middle portion of the bellows, thus providing two elastic chambers 51, 52 is a girdle ring 53, Fig. 3, comprising co-operating half-sections having a cylindrical inner wall 54 and inwardly and outwardly-extending smooth portions 56, 57 with which the outer portions of the walls of the chambers contact on compression. The ends of the bellows terminate in beads 60 which are secured to a lower end casting 69 and to the top portion 74 of the housing 75 by horn-shaped section rings 65. The bellows is connected with an air or other fluid-containing tank 95, Fig. 2, by a pipe 93, the flow of fluid being controlled by a non- return disc-valve 104, Fig. 3, and byepassages 105 which restrict the return flow from the tank on expansion of the device. The valve 104 is adapted to move between seats 102, 103 in a casing 85 to which the pipe 93 is connected, and is controlled by a weighted pendulum member 106 suspended by a universal joint from the upper end of the casing 85. In the normal position of the pendulum, i.e. coaxial with the casing, and on compression of the bellows, a raised portion 104<1> on the valve 104 engages the lower end of the pendulum and the valve is thus kept open permitting free flow of fluid to the tank 93, the increasing compression of the fluid acting to resist the shock. On lateral or longitudinal tilting of the vehicle body, the pendulum swings towards the wall of the casing 85 and the resulting compression of the bellows causes the valve to engage its upper seat and prevent communication with the tank so that the resistance offered by the compression of the fluid increases at a greater rate than when the fluid in the tank is available. A rubber annulus 109 on the pendulum cushions the impact with the casing and a pin fixed in the casing prevents movement of the pendulum in undesired directions. In a modification, flat springs secured to the pendulum maintain it against free movement. The air tank 93 may be mounted directly above the bellows. In a modified construction, Fig., 11 (not shown), the bellows contains a removable inner tube which is formed at its upper end to engage both sides of a flange on a member fixed to the valve casing. The central portion of the bellows is constructed by a tubular, peripherallysplit ring. In another construction, Fig. 8, the upper and lower ends 130, 136 of the bellows are secured respectively to telescoping tubular members 128, 133, the tube 128 being ball-jointed to the chassis 121 while the tube 133 is connected at its lower end to a wheel support. The constricted portion 140 of the bellows contains a circumferential bead 141 in which engage the outer curved ends of co-operating apertured stampings forming a reinforcing or spacing member 142 on the inside of the bellows. The girdle ring 147 comprises co-operating halfsections having flanges 148 engaging the portion 140. In a further construction, Fig. 9 (not shown), the control valve is mounted in the tank 93 and has a pair of spaced tongues engaging one of the securing bolts of the valve casing to prevent rotation of the valve, while the upper end of the bellows is fixed to the chassis and ball-jointed to a tubular member corresponding to the tube 128, Fig. 8. Fig. 12 shows another form of control comprising a pendulum 191 swivelly mounted at its upper end in the casing 181 and containing side passages 193 and a central passage 194 adapted normally to lie over a passage 197 in a plate 184 to which is secured an inner tube inside the bellows. In operation, tilting of the body causes the pendulum to swing towards the casing, thus closing the passage 197 to interrupt communication between the bellows and tank. In another construction, Fig. 13 (not shown), an additional valve-controlled, air tank is mounted within the bellows. The tank 93 may be mounted directly above the bellows which may consist of rubber and cotton cords vulcanized together. The Specification also contains some theoretical discussion illustrated by graphs.