| 摘要 |
<p>1,186,145. Lift truck. CASCADE CORP. 19 Feb., 1968 [21 Aug., 1967], No. 8042/68. Heading B8H. [Also in Division F2] In load-handling apparatus, e.g. as shown clamps 26a, 28a on relatively movable arms 26, 28 mounted on a table 12 on a lift truck and rotated about a horizontal axis 23 and supporting large paper rolls, in which the load support is driven by a reversible hydraulic motor 32, e.g. through worm gear 34, driven by a pump 106 through a reversing valve 108 and return and delivery conduits 118, 116, overrunning of the motor 32 due to the load is inhibited by a valve arrangement 38 responsive to pressure in the delivery conduit 116 or 118, which valve arrangement, on delivery pressure falling due to the motor acting as a pump, is effective to throttle the motor exhaust and brake the motor. As shown in Fig. 2, the valve arrangement comprises a spool 68 spring- biased to a central position in a bore 46. With conduit 116 acting as the delivery conduit, pressure therein acts on the left-hand end of spool 68 forcing it to the right to uncover inlet port 58 to the motor 32, and to connect outlet port 62 to the return conduit 118 by a groove 72 on the spool 68. The parts are connected to the motor through tubes 86, 100 in oversize bores 64, 66 and formed with radial bores 88, 102. On overrunning of motor 32 occurring, due to an unbalanced load, the delivery pressure 116 falls and spool 68 moves back towards the left to throttle the exhaust. With line 118 acting as the delivery line, the spool acts in an equivalent fashion in the opposite direction. Grooves 74 are provided on the spool to equalize the external pressures acting thereon.</p> |
