| 摘要 |
842,331. Vehicle stands. SIDLER Ltd, and BUTTERWORTH, A. J. April 14, 1958 [Feb. 26, 1957], No. 6490/57. Class 79(3). An apparatus for manoeuvring a motor vehicle in a confined space, comprises, in association with each driven road wheel, a roller, having a convex under-surface and a spherical or conical upper surface rotatably mounted on a telescopic member the other end of which is attached to part of the road wheel mounting, e.g. the axle casing, in a manner which allows it to swing about a fore-and-aft axis of rotation lies in a forecontract or extend the telescopic member, and for constraining its outer and lower portion to move in such a path that when a part of the convex under-surface of the roller contacts the ground its axis of rotation lies in a fore and-aft direction and its conical upper surface is in contact with the road wheel which is raised above the ground. The axis of rotation of each roller is inclined to a transverse vertical plane in opposite directions to each other whereby rotation of the driven wheels causes each roller to move the vehicle laterally in the same direction. Several embodiments of the invention are described in which the telescopic member is a hydraulic ram 18 which may be extended by operating a pump driven from the vehicle engine and retracted by either an external spring as 31 Fig. 4, or 81, Fig. 5 or a pair of cross wound springs 91, Fig, 18, extending between a boss 89 and a screw 86 rotation of which preloads the springs. In Figs. 4 and 15 the hydraulic ram 18 is pivotally mounted at 28 and its outer end is guided by a link 22 pivoted to the ram at 23 and to a retaining bracket at 13. In Fig. 8 the ram 18 is mounted in rubber blocks held by brackets 70, the blocks permitting transverse but not fore-and-aft movement. In Figs. 11 and 12 the ram 18 has an auxiliary ram 77 which comes into operation when the ram 18 is fully extended. In these embodiments internal or external spring means may be provided to return the rams to the retracted positions. Specification 832,680 is referred to. |
