The document discusses different types of clutches. It describes clutches as a coupling used to transmit power between a driving shaft and driven shaft that may need to start or stop frequently. It then discusses various types of clutches including disc clutches, cone clutches, centrifugal clutches, positive contact clutches, and others. Disc clutches have flanges on the driving and driven shafts to transmit power. Cone clutches use two cones to engage or disengage. Centrifugal clutches use shoes that move outward via centrifugal force to engage the driven member. Positive contact clutches have projections on one flange that engage recesses on the other.