Thomson’s electromagnetic friction clutches and brakes provide efficient, electrically switchable operation between a motor and a load. Clutches link the motor to the load by coupling two parallel shafts through the use of pulleys, gears or sheaves. Power-on and Power-off (either spring-set or permanent magnet design) brakes provide an electrically switchable means of stopping and/or holding the load. While the field (electromagnet) assembly is fixed and prevented from rotating, the rotor (spring-set design) or armature (permanent magnet design) assembly is secured to the shaft. For tooth clutches, couplings, and brakes, when the coil is energized the tooth profile of the armature positively engages the tooth profile of the rotor, coupling the two in-line or parallel shafts - thus driving the load. These are perfect for either static or low speed engagement applications.
The Genuine Wrap Spring clutches and brakes provide hundreds of simple motion processes that can be controlled through three basic control functions: overrunning, start-stop, and single revolution. These pre-packaged, pre-assembled units are as easy to select as they are to install. The basic wrap spring clutch consists of three elements: an input hub, an output hub, and a spring whose inside diameter is slightly smaller than the outside diameter of the two hubs. When the spring is forced over the input and output hubs, rotation wraps it down tightly on the hubs, positively engaging them. The greater the force of rotation, the more tightly the spring grips the hubs. As a result, a spring clutch or brake will not slip.