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winch,mechanical device for hauling or lifting consisting essentially of a movable drum around which a cable is wound so that rotation of the drum produces a drawing force at the end of the cable. A windlass is essentially the same device as a winch, except that a winch may be power-driven whereas a windlass is usually hand-powered and somewhat less sophisticated. Winches are normally equipped with a ratchet wheel and a pawl to prevent slippage of the load, and brakes that allow a load to be lowered or released at a controlled rate. A hoist is another closely related device, mounted so as to be movable (as in a traveling crane). Winches and hoists are widely used in cargo handling, e.g., in ships, factories, and warehouses, and also function as the power unit in derricks, power cranes, and power shovels. A car puller is a winch with a vertical drum axis, used to position railroad cars in freight yards. Certain military and construction vehicles designed for off-road use are equipped with engine-powered winches that can be used for lifting and hauling or to extricate the vehicle should it become stuck in areas where traction is poor.
(also hoist or windlass), a machine for moving loads by means of a flexible element (a cable or chain). Tractive force is transmitted to the flexible element from a drum or sprocket driven by connecting mechanisms.
Winches are divided into stationary and mobile types, with manual and machine drives (electric motors, internal-combustion engines, and less frequently steam, hydraulic, or pneumatic power units). The connecting mechanisms may consist of gear or worm-gear trains (usually in reduction gears), friction or belt drives, and combinations of them. A drum hoist operates on the principle of a simple winch but differs in that it has connecting mechanisms. In chain hoists the tractive force is applied to a chain by a rotating sprocket. Lever winches are also used. When the drive lever is rocked back and forth, the cable is alternately gripped by two clamps and forced through the traction (lever) mechanism. The tractive force (load-carrying capacity) of the winches regulated by GOST (All-Union State Standard) ranges from 2.5 to 200 kilonewtons (0.25 to 20 tons).
Winches are used as independent machines to perform loading-unloading, construction, assembly, repair, and warehousing operations; they are also used to shunt rolling stock, to skid timber, to stack wood, and to berth vessels and raise anchors (capstans and windlasses), and also as a part of excavating and road machines, cranes, pile drivers, cableways, draglines, and drilling rigs.
REFERENCESSredstva maloi mekhanizatsii dlia pogruzochno-razgruzochnykh i transportnykh rabot. Compiled by M. A. Preobrazhenskii. Moscow, 1959.
Bazanov, A. F. Pod”emno-transportnye mashiny. Moscow, 1969.
E. M. STARIKOV