Clutch

Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Clutch shopping experience:

1. Compare - without doubt the biggest advantage that the Clutch offers shoppers today is the ability to compare thousands of Clutch at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Clutch? Wrong! If the Clutch is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Clutch then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Clutch? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Clutch and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Clutch wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Clutch then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Clutch site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Clutch, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Clutch, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

{{Location_map | 100x100| AlternativeMap = Clutch_explosion.jpg| caption = Clutch for a drive shaft: The clutch disc (center) spins with the flywheel (left). To disengage, the lever is pulled (black arrow), causing a white pressure plate (right) to disengage the green clutch disc from turning the drive shaft, which turns within the thrust-bearing ring of the lever. At rest, all 3 rings connect, with no gaps.| label = Flywheel | label_size=87 | marksize=1 | position = right | background = #44AADD| lat = 88.2 | long = 61.6| width = 305 | float = right-->

hub is attached to the disc with springs to damp chatter.

A clutch is a mechanism for transmitting rotation, which can be engaged and disengaged. Clutches are useful in devices that have two rotating shafts. In these devices, one shaft is typically driven by a motor or pulley, and the other shaft drives another device. In a drill, for instance, one shaft is driven by a motor, and the other drives a drill chuck. The clutch connects the two shafts so that they can either be locked together and spin at the same speed, or be decoupled and spin at different speeds.

Vehicle clutches There are many different vehicle clutch designs but most are based on one or more friction discs, pressed tightly together or against a flywheel using spring (device). The friction material varies in composition depending on whether the clutch is dry or wet, and on other considerations. Friction discs once contained asbestos, but this has been largely eliminated. Clutches found in heavy duty applications such as trucks and competition cars use ceramic clutches that have a greatly increased friction coefficient, however these have a "grabby" action and are unsuitable for road cars. The spring pressure is released when the clutch pedal is depressed thus either pushing or pulling the diaphragm of the pressure plate, depending on type, and the friction plate is released and allowed to rotate freely.

When engaging the clutch, the engine speed may need to be increased from idle, using the manual throttle, so that the engine does not stall (although in most cars, especially diesels, there is enough power at idling speed that the car can move. This requires fine control of the clutch). However, raising the engine speed too high while engaging the clutch will cause excessive clutch plate wear. Engaging the clutch abruptly when the engine is turning at high speed causes a harsh, jerky start. This kind of start is desired in drag racing and other competitions, however.

Wet and dry clutches A 'wet clutch' is immersed in a cooling lubricating fluid, which also keeps the surfaces clean and gives smoother performance and longer life. Wet clutches, however, tend to lose some energy to the liquid. A 'dry clutch', as the name implies, is not bathed in fluid. Since the surfaces of a wet clutch can be slippery (as with a motorcycle clutch bathed in engine oil), stacking multiple clutch disks can compensate for slippage. Most Moto Guzzi, Ducati, and BMW motorcycles typically use a dry clutch much like a car.

Clutch operation in automobiles In a automobile the clutch is operated by the left-most pedal using hydraulics or a cable connection from the pedal to the clutch mechanism. Even though the clutch may physically be located very close to the pedal, such remote means of actuation are necessary to eliminate the effect of slight engine movement, engine mountings being flexible by design. With a rigid mechanical linkage, smooth engagement would be near-impossible, because engine movement inevitably occurs as the drive is "taken up". No pressure on the pedal means that the clutch plates are engaged (driving), while depressing the pedal disengages the clutch plates, allowing the driver to shift gears or coast.

A manual transmission contains cogs for selecting gears. These cogs have matching teeth, called dog teeth, which means that the rotation speeds of the two parts have to match for engagement. This speed matching is achieved by a secondary clutch called a synchronizer, a device that uses frictional contact to bring the two parts to the same speed, and a locking mechanism called a blocker ring to prevent engagement of the teeth (full movement of the shift lever into gear) until the speeds are synchronized.

Non-powertrain clutches in automobiles There are other clutches found in a car. For example, a belt-driven engine cooling fan may have a clutch that is heat-activated. The driving and driven elements are separated by a silicone-based fluid. When the temperature is low, the fluid is thin and so the clutch slips. When the temperature is high, the fluid thickens, causing the fan to spin. There are also electronically engaged clutches (such as for an Air conditioning compressor) that use magnetic force to lock the pulley and compressor together.

Clutch operation in motorcycles On most motorcycles, the clutch is operated by the clutch lever, located on the left handlebar. No pressure on the lever means that the clutch plates are engaged (driving), while pulling the lever back towards the rider will disengage the clutch plates, allowing the rider to shift gears. Motorcycle clutches are usually made up of a stack of alternating plain steel and friction plates. One type of plate has lugs on its inner diameter that key it to the engine crankshaft, while the other type of plate has lugs on its outer diameter that key it to a basket that turns the transmission input shaft. The plates are forced together by a set of coil springs when the clutch is engaged. Racing motorcycles often use slipper clutches to eliminate the effects of engine braking.

Centrifugal clutches Some cars and mopeds have a centrifugal clutch, using centrifugal effects to engage the clutch above certain Revolutions per minute, see Saxomat.

Other clutches

Dog clutches
Cone clutches
Safety clutches: These devices allow a rotating shaft to "slip" when higher than normal resistance is encountered on a machine. An example of a safety clutch is the one mounted on the driving shaft of a large grass mower. The clutch will "slip" or "give" if the blades hit a rock, stump, or other immobile object.
Overrunning clutch or freewheel
Single plate & Multi-plate friction clutches

Single disc or plate clutch: This type of clutch is used almost exclusively in vehicles and has three main parts:

(i) Driving members
(ii) Driven members
(iii)operating members

Centrifugal clutch and semi-centrifugal clutch
Fluid coupling
Electromagnetic clutch