Ogura's SMC spring-engaged clutches engage any time power is released. When the clutch is disengaged, a magnetic coil pulls back a pressure plate and a series of friction discs, so no torque is transferred between the input and output hubs on the clutch. When the coil is no longer receiving voltage, a series of springs push the pressure plates together engaging the rotor to the drive hub.

Spring-applied clutches can be used in construction elevator applications, so if power fails the clutch can automatically engage a centrifugal brake which would allow a car to descend even if no power was present.  The units can also be used as standby or creep drives. Other applications include machine tool and industrial machinery, such as conveyors.  The key advantage with the spring-applied clutch is that power is only required when the clutch needs to disengage, so for applications where the clutch needs to be engaged for a majority of the time, no electrical power is consumed.

The spring-applied clutch can also be used when a manual backup system/override is required.  An example would be for a flow gate on a dam that would normally be powered open and closed with an electric motor.  When the motor is driving, the gate open and closed, power is also going to the spring-applied clutch keeping it disengaged, but if power fails, then the clutch becomes engaged to the motor.  The clutch would be attached to a gear box with a manual crank so that the system can be manually driven open or closed as required.  This type of system can also be used for heavy containment doors for hazardous materials or manual backup systems for amusement park rides. Ogura spring-applied clutches are available in ten sizes from 10-960 lb. ft. Standard coil voltage is 24, but modified voltages are available.  Bore sizes can also be modified to meet customer requirements.