Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

124 Chapter 3 Direct Power Transfer Devices
Figure 3-51 Friction disks are
compressed by an adjustable
spring. Square disks lock into the
square hole in the left shaft, and
round disks lock onto the square
rod on the right shaft.
Figure 3-52 Friction clutch
torque limiter. Adjustable spring
tension holds the two friction surfaces
together to set the overload
limit. As soon as an overload is
removed, the clutch reengages. A
drawback to this design is that a
slipping clutch can destroy itself if
it goes undetected.
Figure 3-53 Mechanical keys. A
spring holds a ball in a dimple in
the opposite face of this torque
limiter until an overload forces it
out. Once a slip begins, clutch
face wear can be rapid. Thus,
this limiter is not recommended
for machines where overload is
common.