| 摘要 |
1,202,084. Winches. PORTASILO Ltd. 20 Dec., 1968 [6 Oct., 1967], No. 45896/67. Heading B8B. [Also in Division F2] A winching arrangement for moving a scraper bucket between opposite ends of a boom, comprises run in and run out cables 32, 36 associated with winding drums 26, 27, one drum being selectively driven whilst the other selectively has a retarding force applied thereto during its movement in a cable unwinding direction, the retarding force increasing with increase in the speed of drum rotation. The retarding force is hydraulically applied to the relevant drum by an adjustable spring-loaded throttle valve situated in the return line of an associated hydraulic circuit including a reversible pump 61, 62 driven by the drum through a chain 58, 59. Both drums 26, 27 are freely mounted on a shaft 38 chain driven from a motor 28, and each is drivingly connectible thereto through an hydraulically operated clutch, the hydraulic circuits associated with the arrangement being supplied from an hydraulic reservoir 52. Solenoid-operated valves W, X, Y, Z controlling the sequence of bucket operation are controlled by switches 69, 71 actuated by a cam 68 which is driven through a reduction gear 67 from the shaft 66 of pump 61. In operation, the drum 26 is driven to cause the bucket to scrape material while the drum 27 pays out freely, the throttle valve being brought into operation to retard the drum 27 as the bucket approaches the end of its inward run, whereupon the bucket is lifted and tilted for emptying. The drive is next transferred to the drum 27 while the pay out of the drum 26 is retarded to prevent oscillations of the bucket and hold it up adjacent the boom as it moves to the outer end thereof. At the boom outer end, the bucket is lowered to the ground for another cycle, by the drive to both drums being disconnected and a disc brake 63 being applied to the pump 61 and hence drum 26, and the drum 27 paying out against the retarding force. A bucket parking condition is provided for in which both drums are disconnected from the drive and disc brakes 63, 64 applied to both. |
