Clutch

A clutch is a device used to connect or disconnect a driven component from the prime mover of the system.

Where Clutches are used ?

Clutches are used whenever the transmission of power or motion must be controlled either in amount or over time (e.g., electric screw drivers 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.

Types of Clutches

1. Positive clutches

2. Friction clutches

   • Axial clutches

   • Rim clutches

Positive Clutches

Positive clutches are designed to transmit torque without slip. The jaw clutch is the most common type of positive clutch. These are made with square jaws for driving in both directions or spiral jaws for unidirectional drive. Engagement speed should be limited to 10 rpm for square jaws and 150 rpm for spiral jaws. If disengagement under load is required, the jaws should be finish-machined and lubricated.

Friction Clutches

Friction clutches are designed to reduce coupling shock by slipping during the engagement period. They also serve as safety devices by slipping when the torque exceeds their maximum rating. They may be divided into two main groups, axial and rim clutches, according to the direction of contact pressure. The cone clutch and the disk clutch are examples of axial clutches. The disk clutch may consist of either a single plate or multiple disks.