BASIC TECHNICAL WINCH INFORMATION
Winches are rated in line pull, and are usually measured pounds, lbs. or Kg.. The rated line pull is with the first layer of wire rope on the winch drum / single layer.
There are three basic power supply types of winch.
(1.) Low Voltage, = 12v. and 24 volt.
(2.) High Voltage, = 110 volt.
(3.) Hydraulic Only.
Low Voltage and Hydraulic winches are suitable for outdoor use.
The winch sees only the load, that is to say that the line pull is the amount of force the winch needs to produce to move an object. This would be the figure that would be measured on a strength gauge if one was fitted in series with the line (wire rope).
When deciding which model winch to buy, consider the length of wire rope required, as the rated line pull is quoted with the first layer of wire rope on the winch drum. As you winch in the winch becomes less powerful with each layer of wire rope on the winch drum. You should also remember that winch cables never spool onto the winch drum evenly, this results in cable bunching which in turn compounds the problem of layer build up and in turn a loss of pulling power as described below.
As a guide for each layer of wire rope on the drum deduct 10% off the rated line pull. e.g. A winch with a line pull of say 6,000 lbs.. will have a line pull of 5,400lbs.. on the second layer, 4,860 lbs.. on the third layer and 4,374 lbs.. on the fourth layer, etc. So if you need to pull 6,000 lbs.. for any distance, you will need a winch with a greater rated line pull to start with.
You can effectively double the line pull capacity of a winch, by applying what is called a 'double line'. By using a Snatch Block / Pulley Block, you will double the line pull of the winch, but will halve the winching speed, due to the gearing ratio, this is not usually important and is often safer if you are pulling an abnormal load. However, for every pulley you use there is a frictional loss of approximately 10% per pulley.
To effect a true double line, attach the snatch block to the load, wind the wire rope from the winch drum out and around the snatch block pulley, then back and attach the wire rope to a place adjacent to the winch itself. This is a 'Double Line'.
This drawing shows a typical Double Line:
A Double Line as used for self recovery using an anchor point such as a tree.
Indirect Double Line Pull
Indirect pulling may be required because of obstacles. The pulley block is attached to the load and the wire rope is attached to an anchor point offset from the direction in which the load is to be moved. Note that this procedure is not recommended unless necessary as the winch pulling power and line speed will decrease as the angle between the wire rope increases.
Single Line Pull
Whilst this configuration uses a pulley block it is only a single line pull and the pulling power will be as the winch line pull rating as described above.
There are different types of wire rope available. The best quality, often referred to as aircraft quality, are of wire core construction, whereas the cheaper types are of nylon core construction. i.e. There is actually a nylon core in the centre of the wire rope, instead of a wire core as in top quality ropes.
Then there is the make up of the wire itself, including how many strands of wire there are, this can effect the strength and flexibility of the rope.
Make sure that if a hook is attached, the hook is also capable of handling the load, and that it is correctly stamped with a safe working load.
Cheap wire ropes never pay in the long term and can be dangerous. You only get what you pay for.
attach the winch cable back onto itself as shown. Always use a sling with a shackle when using a tree. Make sure you use a soft sling or "TREE SAVER" to prevent damaging the tree.
It is good practice to use a heavy blanket or jacket over the wire rope. If a rope failure should occur the weight of the cloth will act as a damper and help prevent the broken rope from whipping. A raised vehicle hood will also give some protection should the rope break. Also, the blanket acts as a visual warning to bystanders and is likely to prevent them from walking into or tripping over the wire rope.
You should always make sure that everyone keeps well back and away from any winching activity. However, in the case of a long distance pull you may not see a person who inadvertently walks towards the wire rope, such a cover will help bring the wire rope to their attention. It is recommended that in such circumstances two operators should be in attendance.
Using Cable Clamps on a Wire Rope.
1. Clamps should be spaced 6 rope diameters apart.
2. Ensure that when forming a loop or fitting a thimble that the first and last clamps are not over tightened so
as to damage the rope.
3. Both the nuts on each clamp should be tightened equally.
4. Re-tighten the nuts after use and keep checking them on a regular basis.
5. Make sure that you use the correct type and size of cable clamp.
6. You must use a minimum of three clamps as shown below.
7. Make sure that you fit the clamps exactly as shown below. This is VERY IMPORTANT.
When handling Wire Ropes always wear protective gloves and use a hand saver bar.
Check the Wire Rope regularly for any damage or wear.
Never use a worn or damaged Wire Rope.
Make sure that the Wire Rope is correctly rated for the winch and the load, including any hooks or shackles it is attached to.
The Wire Rope should be wound neatly onto the winch drum.
All Wire Ropes should come with a safety Test Certificate.
Wire Ropes can be DANGEROUS if not handled correctly.
WINCHES MUST NOT UNDER ANY CIRCUMSTANCES BE USED FOR THE LIFTING OR TRANSPORTING OF PEOPLE.
Read The Handbook On Safety Before Using A Winch And Make Sure That You Fully Understand It.
THIS INFORMATION IS INTENDED AS A GUIDE ONLY.
The above information only briefly touches on the principals of winching and is NOT comprehensive.
think you know everything because you have read this.