A clutch is a mechanical device that engages and disengages the power, transmission, especially from driving shaft to driven shaft. Clutches are used whenever the transmission of power or motion must be controlled either in amount or over time (e.g., electric screwdrivers limit how much torque is transmitted through use of a clutch; clutches control whether automobiles transmit engine power to the wheels). In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). In these devices, one shaft is typically attached to an engine or other power unit (the driving member) while the other shaft (the driven member) provides output power for work. While typically the motions involved are rotary, linear clutches are also possible. In a torque-controlled drill, for instance, one shaft is driven by a motor and the other drives a drill chuck. The clutch connects the two shafts so 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). our blog http://engmania7.blogspot.com/ our facebook page https://www.facebook.com/Egy.Mechanical.Engineer our google plus https://plus.google.com/u/0/b/116672434216174352691/+MechabooksBlogspot/posts On twitter https://twitter.com/EngMania7 youtube channel http://www.youtube.com/c/EngineeringMania2