CLUTCHES

A clutch is a mechanical device which provides for the transmission of power (and therefore usually motion) from one component (the driving member) to another (the driven member). The opposite component of the clutch is the brake.

Clutches are used whenever the ability to limit the transmission of power or motion needs to be controlled either in amount or over time. Clutches control whether automobiles transmit engine power to the wheels.

In the simplest application clutches are employed in devices which have two rotating shafts. In these devices one shaft is typically attached to a motor or other power unit (the driving member) while the other shaft (the driven member) provides output power for work to be done. The clutch connects the two shafts so that they may be locked together and spin at the same speed (engaged), locked together but spinning at different speeds (slipping), or unlocked and spinning at different speeds (disengaged).
Friction disk clutches generally are classified as "Push Type" or "Pull Type" depending on the location of the pressure plate fulcrum points. In a pull type clutch, the action of pressing the pedal pulls the release bearing, pulling on the diaphragm spring and disengaging the vehicle drive. The opposite is true with a push type, the release bearing is pushed into the clutch disengaging the vehicle drive. In this instance, the release bearing can be known as a thrust bearing.


 

http://en.wikipedia.org/wiki/Clutch

http://www.8thcivic.com/forums/mechanical-problems-technical-chat/201490-2nd-gear-grind-theory-please-read-7.html

http://www.carcraft.com/techarticles/clutch_basics/photo_06.html