Winch
Encyclopedia
A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the "tension" of a rope
or wire rope
(also called "cable" or "wire cable"). In its simplest form it consists of a spool
and attached hand crank
. In larger forms, winches stand at the heart of machines as diverse as tow truck
s, steam shovel
s and elevator
s. The spool can also be called the winch drum. More elaborate designs have gear
assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. Some may include a solenoid brake
and/or a mechanical brake or ratchet and pawl
device that prevents it from unwinding unless the pawl is retracted.
. When trimming a line on a sailboat, the crew member turns the winch handle with one hand, while tailing (pulling on the loose tail end) with the other to maintain tension on the turns. Some winches have a "stripper" or cleat to maintain tension. These are known as "self-tailing" winches.
Winches are frequently used as elements of backstage mechanics to move scenery
in large theatrical productions. Winches are often embedded in the stage floor and used to move large set pieces on and off.
Winches have recently been fabricated specifically for water and snow sports (e.g. wakeboarding
, wakeskating
, snowboarding
, etc.). This new generation of winches is designed to pull riders swiftly across a body of water or snow, simulating a riding experience that is normally supplied by a boat, wave runner, or snow mobile.
and other lines, and in larger applications to supplement and relieve tension on the primary winch mechanisms.
are often launched using a winch mounted on a heavy vehicle. This method is widely used at European gliding clubs, as a cheaper alternative to aerotowing. The engine is usually a large diesel
, though hydraulic fluid
engines and electrical motors are also used. The winch pulls in a 1,000 to 1,600-metre (3,000 to 5,500 ft) cable, made of high-tensile steel wire or a synthetic fiber, attached to the glider. The cable is released at a height of about 400 to 700 metres (1,300 to 2,200 ft) after a short, steep climb.
(Histories 7.36), where he describes how wooden winches were used to tighten the cables for a pontoon bridge across the Hellespont in 480 B.C. Winches may have been employed even earlier in Assyria
. By the 4th century BC, winch and pulley hoists
were regarded by Aristotle
as common for architectural use (Mech. 18; 853b10-13).
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...
or wire rope
Wire rope
thumb|Steel wire rope Wire rope is a type of rope which consists of several strands of metal wire laid into a helix. Initially wrought iron wires were used, but today steel is the main material used for wire ropes....
(also called "cable" or "wire cable"). In its simplest form it consists of a spool
Spool
Spool can mean one of the following:*Spool, a usually low-flanged or unflanged cylinder on which thread, wire, cable, paper, film, or tape is wound for distribution or use....
and attached hand crank
Crank (mechanism)
A crank is an arm attached at right angles to a rotating shaft by which reciprocating motion is imparted to or received from the shaft. It is used to change circular into reciprocating motion, or reciprocating into circular motion. The arm may be a bent portion of the shaft, or a separate arm...
. In larger forms, winches stand at the heart of machines as diverse as tow truck
Tow truck
A tow truck is a vehicle used to transport motor vehicles to another location , or to recover vehicles which are no longer on a drivable surface.Towing services are generally provided by an emergency road service operator...
s, steam shovel
Steam shovel
A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power shovel or excavator. They played a major role in public works in the 19th and early 20th century, being key to the construction of railroads...
s and elevator
Elevator
An elevator is a type of vertical transport equipment that efficiently moves people or goods between floors of a building, vessel or other structures...
s. The spool can also be called the winch drum. More elaborate designs have gear
Gear
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine....
assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. Some may include a solenoid brake
Solenoid brake
A Solenoid Brake is an electrically controlled brake. The brake is turned on and off by an electrical solenoid. Typically a spring engages the brake when unpowered, and the solenoid releases it when powered....
and/or a mechanical brake or ratchet and pawl
Ratchet (device)
A ratchet is a device that allows continuous linear or rotary motion in only one direction while preventing motion in the opposite direction. Because most socket wrenches today use ratcheting handles, the term "ratchet" alone is often used to refer to a ratcheting wrench, and the terms "ratchet"...
device that prevents it from unwinding unless the pawl is retracted.
Applications
The rope is usually stored on the winch, but a similar machine that does not store the rope is called a capstanCapstan (nautical)
A capstan is a vertical-axled rotating machine developed for use on sailing ships to apply force to ropes, cables, and hawsers. The principle is similar to that of the windlass, which has a horizontal axle.- History :...
. When trimming a line on a sailboat, the crew member turns the winch handle with one hand, while tailing (pulling on the loose tail end) with the other to maintain tension on the turns. Some winches have a "stripper" or cleat to maintain tension. These are known as "self-tailing" winches.
Winches are frequently used as elements of backstage mechanics to move scenery
Theatrical scenery
Theatrical scenery is that which is used as a setting for a theatrical production. Scenery may be just about anything, from a single chair to an elaborately re-created street, no matter how large or how small, whether or not the item was custom-made or is, in fact, the genuine item, appropriated...
in large theatrical productions. Winches are often embedded in the stage floor and used to move large set pieces on and off.
Winches have recently been fabricated specifically for water and snow sports (e.g. wakeboarding
Wakeboarding
Wakeboarding is a surface water sport which involves riding a wakeboard over the surface of a body of water. It was developed from a combination of water skiing, snow boarding and surfing techniques....
, wakeskating
Wakeskating
Wakeskating is a water sport and an adaptation of wakeboarding that employs a similar design of board manufactured from maple or from fibreglass. Unlike wakeboarding, the rider is not bound to the board in any way, which gives the sport its own unique challenges...
, snowboarding
Snowboarding
Snowboarding is a sport that involves descending a slope that is covered with snow on a snowboard attached to a rider's feet using a special boot set onto mounted binding. The development of snowboarding was inspired by skateboarding, sledding, surfing and skiing. It was developed in the U.S.A...
, etc.). This new generation of winches is designed to pull riders swiftly across a body of water or snow, simulating a riding experience that is normally supplied by a boat, wave runner, or snow mobile.
Tirfors
Tirfors, also commonly known as griphoists, are winches that use self-gripping jaws instead of spools to move rope or wire through the winch. Powered by moving a handle back and forth, they allow one person to move objects several tons in weight.Snubbing winch
This is a vertical spool with a ratchet mechanism similar to a conventional winch, but with no crank handle or other form of drive. The line is wrapped around the spool and can be tightened and reeled in by pulling the tail line, the winch takes the load once the pull is stopped with little operator tension needed to hold it. They also allow controlled release of the tension by the operator using the friction of the line around the ratcheted spool. They are used on small sailing boats and dinghies to control sheetsSheet (sailing)
In sailing, a sheet is a line used to control the movable corner of a sail.- Fore-and-aft rigs:Fore-and-aft rigs comprise the vast majority of sailing vessels in use today, including effectively all dinghies and yachts. The sheet on a fore-and-aft sail controls the angle of the sail to the wind,...
and other lines, and in larger applications to supplement and relieve tension on the primary winch mechanisms.
Wakeskate winch
Wakeskate winching, which is the popular term today, is a growing hobby for many watersports enthusiasts. It consists of an engine, spool, rope, handle, frame, and some sort of simple transmission. The person being towed walks (or swims) away from the winch and pulls out all of the rope. When the winch is engaged, it pulls the boarder usually between 15 to 25 mph (6.7 to 11.2 ). Winches are popular for people wanting to board on ponds and lakes, or just don't have a boat. Also, the winch can either be mounted on the trailer hitch of a vehicle, set into the ground by stakes, or tied to a tree. These winches have also been modified for use by skiers and snowboarders in cities.Glider winch
GlidersGlider (sailplane)
A glider or sailplane is a type of glider aircraft used in the sport of gliding. Some gliders, known as motor gliders are used for gliding and soaring as well, but have engines which can, in some cases, be used for take-off or for extending a flight...
are often launched using a winch mounted on a heavy vehicle. This method is widely used at European gliding clubs, as a cheaper alternative to aerotowing. The engine is usually a large diesel
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
, though hydraulic fluid
Hydraulic fluid
Hydraulic fluids, also called hydraulic liquids, are the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water...
engines and electrical motors are also used. The winch pulls in a 1,000 to 1,600-metre (3,000 to 5,500 ft) cable, made of high-tensile steel wire or a synthetic fiber, attached to the glider. The cable is released at a height of about 400 to 700 metres (1,300 to 2,200 ft) after a short, steep climb.
History
The earliest literary reference to a winch can be found in the account of Herodotus of Halicarnassus on the Persian WarsGreco-Persian Wars
The Greco-Persian Wars were a series of conflicts between the Achaemenid Empire of Persia and city-states of the Hellenic world that started in 499 BC and lasted until 449 BC. The collision between the fractious political world of the Greeks and the enormous empire of the Persians began when Cyrus...
(Histories 7.36), where he describes how wooden winches were used to tighten the cables for a pontoon bridge across the Hellespont in 480 B.C. Winches may have been employed even earlier in Assyria
Assyria
Assyria was a Semitic Akkadian kingdom, extant as a nation state from the mid–23rd century BC to 608 BC centred on the Upper Tigris river, in northern Mesopotamia , that came to rule regional empires a number of times through history. It was named for its original capital, the ancient city of Assur...
. By the 4th century BC, winch and pulley hoists
Hoist (device)
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a...
were regarded by Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
as common for architectural use (Mech. 18; 853b10-13).
See also
- Capstan equationCapstan equationThe capstan equation or belt friction equation, also known as Eytelwein's formula, relates the hold-force to the load-force if a flexible line is wound around a cylinder ....
- Hoist (device)Hoist (device)A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a...
- Hoist (mining)Hoist (mining)In underground mining a hoist or winder is used to raise and lower conveyances within the mine shaft. Modern hoists are normally powered using electric motors, historically with direct current drives utilizing solid-state converters , however modern large hoists utilize alternating current drives...
- ParasailingParasailingParasailing, also known as parascending, or "parakiting" is a recreational kiting activity where a person is towed behind a vehicle while attached to a specially designed canopy wing that reminds one of a parachute, known as a parasail wing...
- PulleyPulleyA pulley, also called a sheave or a drum, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present...
- Steam donkeySteam donkeySteam donkey, or donkey engine is the common nickname for a steam-powered winch, or logging engine widely used in past logging operations, though not limited to logging...