Clutches

6. The Uses of Clutches

Clutches are rotary mechanical power transmission elements. There many uses and applications are:

Clutches are used to engage and disengage the transmission of rotary mechanical power from one system element to another. This allows the driven part of the system to be turned on and off by controlling its power supply.
Clutches are used to control the power from one system element to another. This avoids shock loads and damage to the driven parts.
Clutches are used to disengage the drive from the driven parts. This allows the drive to be started under `no-load' conditions, which allows the drive to be operated at its rated conditions when the driven parts are connected to it. The system will be cost efficient because it will be started by a well matched drive.
Clutches are used as over-running devices. An over-running clutch allows the drive to transmit torque to the driven machine in one direction only. Considering the relative velocities of the drive and driven shafts, relative motion of the drive shaft and driven shaft is permitted with the drive rotating in one direction, but not in the other.
Clutches are used as torque limiting devices. A torque limiting clutch responds to the torque difference across the clutch. At a predefined torque difference, it will completely disengage the two components connected, or will allow a predefined amount of torque to be transmitted, dissipating the excess energy.