Force Limited

Application Examples

Clutches

Magnetic particle clutches have been used as servo-actuators with two clutches driven in opposite direction by a motor drive. Excitation of either clutch results in moving in the selected direction. Force Limited clutches were on all Apollo missions directing the thrust of the service module propulsion engine so as to eliminate tumbling when the engine was operating.

Brakes

Magnetic particle brakes are used as stopping or tensioning devices. They have been used as load members in motor testing in a wide range of torque applications. Some have seen usage as "feel" mechanisms in simulators. Others have been part of robotic dynamic loops. Small Force Limited brakes are used to test motors at 4-6 in-oz torque range and to tension small tubing at 10-12 in-oz torque in manufacturing equipment. Brakes operating at 40-60 in-lbs torque were used in a military aircraft flight simulator, and others at 120-150 in-lbs torque were used in a military aircraft system test rig.

Clutch-Brakes

Magnetic particle clutch-brakes are used to combine both operations such as start-stop or tensioning-stop where the features of magnetic particle devices are needed. One present application drives the star wheel of a bottling line with the clutch excitation adjusted to slip at a value to prevent bottle breakage when the line stops down-stream. The brake is used during down time to control the line.