Which of the following is NOT a friction clutch?

Explanation:

Clutch:

Clutch is a mechanical device used to connect or disconnect the power source from the rest of the of power transmission at the will of the operator.

Types of clutches:

there are mainly two types of clutches

1. Positive clutches:

• The Positive clutches are used when a positive drive is required.
• the simplest type of positive clutch is a Jaw or claw clutch.
• The Jaw clutch permits one shaft to drive another through direct contact of interlocking jaws.
• It consists of two halves, one of which is permanently fastened to a driving shaft by a sunk key.
• the other half is movable and it is free to slide axially on the driven shaft, but it is prevented from turning relatively to its shaft by means of a feather key.

2. Friction Clutches:

• Friction clutch uses frictional force to start the driven shaft from rest and gradually up to proper speed without slipping of the friction surfaces. ex. Centrifugal clutch, Disc clutch, Cone clutch
• A friction clutch has its principal application in the transmission of the power of shafts and machines which must be started and stopped frequently.
• Its application is also found in cases in which power is to be delivered to machines partially or fully loaded.

Characteristics of friction clutches

The material used for lining of friction surfaces of a clutch should have the following characteristics:

• High and uniform coefficient of friction 
• High heat conductivity.
• High resistance to wear and scoring
• Ability to withstand high temperatures caused by slippage.
• It should not be affected by moisture and oil.

Important Points

Fluid clutch 

• In these clutches, power transmission is achieved by means of hydraulic pressure.
• A fluid couplings provide extremely smooth starts and absorb shock
• So, it does not come under friction clutches.