Clutches and brakes Flashcards
3 types of positive contact clutches
square
spiral
multitooth
positive clutch, bidirectional, compact, simple and generate no heat, can only be engaged at slow speeds
square jaw
positive clutch engaged at higher speeds, this clutch drives in one direction only
spiral jaw
positive clutch with many small gears teeth has highest engagement speed of all positive clutch and shock load is transmitted when engaged
multiple tooth
2 types of radial friction clutch
expanding shoe
contracting shoe
3 types of axial friction clutch
single friction
multiple friction
cone clutches
What is the angle of a cone clutch
10-15 degrees
3 types of one way clutch/overrunning
roller ramp
cam type (sprag)
wrap spring
one way clutch, have roller that move upwards up inclined ramp until they are wedge between the outer and inner race members, when reversed the rollers are free to return down the ramp against the stop
roller ramp
one way clutches with inner and outer race that have members with spring loaded cams which lean in one direction and are held by a spring retainer
cam type sprag
one way clutch with a lightly wrapped coiled spring, when loaded tightens to move load
wrap spring clutch
what are 3 applications of overrunning clutches
simple overrunning
indexing
holdback/backstops
overrunning type to prevent backwards motion as well as over speeding (ie fan drive)
simple overruning
overruning type used with rack and pinion gear feed on reciprocation motion (packaging and production line)
indexing
overruning type used on incline conveyor to prevent load from forcing conveyor backwards in the event of failed motor or shutoff
holdback/backstop
