Gear Winches

Gear winch is a stationary machine, which is either motor driven or hand powered. Winch is a kind of mechanical device that is used to turn wire rope about something fixed. A simple gear winch consists a spool and an attached crank. Another name of the spool is winch drum. In a complex form of winch, a winch consists gear assemblies and these gear assemblies are powered by hydraulic, electric, internal combustion or a pneumatic drive. Solenoid brakes may also be there in some gear winches. Apart from solenoid brakes, there may have ratchets or mechanical brakes.

These brakes prevent the winches from unwinding. It is used for either raising-up or for dragging/pulling the load. It has a drum around of it which is warped a chain or rope attached to the load that has to be moved. The drum (spool) around of the gear winch must be movable and a drawing force is generated when the drum starts to rotate. The force is produced at the end of the chain or the rope. Another similar device like the gear winch is a windlass. The only difference between a winch and a windlass is that windlass is always hand driven, but gear winch may be motor driven also. Therefore, a windlass is less sophisticated than a winch.

Peripheral Devices of a Common Gear Winch
The normal devices which are attached with a winch are: a ratchet wheel and a pawl. These two devices prevent the load from being slipped. The other devices which are also equipped with a winch are:

• Brake It helps in controlling the rate of coming down of the load.
• Hoist It helps in the movability of the winch. Example, A traveling crane, in cargo controlling like in factory, ship, warehouse.

Applications of Gear Winches
Gear Winch is used in a car puller with a vertical drum axis. It is used in positioning the railroad cars in freight yards. Another category of winch is engine-powered winch and this type of winch is used in certain construction vehicles and military vehicles which are used for off-road purposes. As an element of backstage machine, winches are used quite frequently. Here, winches are used for lifting and moving large scenery. Winches are often fixed into the stage floor and used in moving large set pieces on and off. Along with industrial applications, winches are also used in cars, gliders and boats for towing purpose. Almost on every ship or boat, there are several winches. The winches in ships and boats are used for pulling anchor or mooring lines, sheets and halyards.

Calculating Winch Power
The winch power is calculated in the following process: Calculate the fore-triangle area in sq.feet and then multiply it by 6. Fore-triangle area means the bounded area by foredeck, forestay and mast in sq.meter. Now, divide the product by 35. At the time of multiplication, number 6 is taken because 6 accounts for sail force and frictional force. At the time of division, number 35 is taken, because the maximum input force value in pound is 35. The final result that will be obtained in this way, will be the optimum rated mechanical advantage in the second gear (low gear) of a optimum powered winch. Say for example, if the fore-triangle area is 300 sq.feet, then multiply it with 6: 300*6=1,800. now, divide it by 35. the quotient will be 51.4. It means that the winch has advantage of 50:1 approximately. Similarly the calculation of the maximum handle load on the winch, more or less is same as to winch power calculation. The only difference is that despite of fore-triangle area, sail area has to be taken into consideration.