| 摘要 |
643,407. Spring suspensions, perambula tor handles. RALPH, H. W. Feb. 23, 1948 No. 5350. [Class 108(ii)] In a four-wheeled vehicle chassis having pivotally mounted thereon four spring- loaded levers on an arm of each of which is rotatably mounted a wheel, each front lever is a bell-crank lever, both arms of which trail rearwardly and one of which carries a front wheel and each: rear lever is a simple lever with one arm trailing rearwardly ,and carrying the rear wheel and the otherwise free arms of each pair of levers on each side of the vehicle are coupled resiliently together by means tending to pull them together. In the arrangement according to Figs. 1 and 2 the front wheels 34, 35 of a pram are carried at the ends of the lower trailing arms 31 of bell-crank levers 29, 30 which are pivotally mounted at the ends of a transverse chassis member 17 welded to longitudinal chassis members 15, 16. The rear wheels 25, 26 are carried at the ends of trailing arms of levers 21, 22 pivotally mounted at the ends of another transverse chassis member 18. The upper arms 36, 37 of the bell-crank levers and the arms 27, 28 of the levers 21, 22 are connected together on each side of the chassis by a pair of springs 38, 39, and links 70. Movement of the springs and levers may be damped by a pin 71 which projects through each arm 36 and 37. In another arrangement (Fig. 3, not shown) wherein the pram body is supported on longitudinal chassis members by a pair of links at the rear end of the body and by a transversely disposed U-shaped link hinged to the underside of the forward part of the body, the downwardly projecting part of the link at each side of the body is anchored to the springs connected between the levers. The ends of the downwardly projecting parts of the link are also adapted to carry a roller of rubber or the like which bears against the underside of the longitudinal chassis members. The spring connecting the levers torgether may.comprise two pairs of springs in tandem or springs and links, and the U-shaped link may be anchored to adjacent ends of the two pairs of springs or between the springs and links. The construction of the link is such as to allow relative movement between one end and the other. In a further arrangement, Fig. 5, longitudinal chassis members 48 carrying transverse members 50 and 51 for pivotally supporting levers 52 and 53 respectively on each side of the chassis, are hinged to the underside of the pram body through an integral transverse member 49. Longitudinal side members 56 forming an extension of the pram handle, are anchored between pairs of springs 58, 59 or a combination of springs and links. A transversely-disposed inverted U-shaped link 60 hingedly mounted on the underside of the body, is anchored at each end to a side member 56. The arrangement is such that tension on the springs may be varied at will by depressing or lifting the pram handle. In a modification (Fig. 6, not shown) applicable to the arrangements described above, the levers may be connected together by a rod one end of which is housed in a hollow or bifurcated part of the forwardly directed arm of a rear lever and includes a compression spring between the end of the rod and a stop thereon. The other end of the rod is connected to the upper arm of a bell-crank lever on the same side of the chassis. |
