The latch assembly is oriented in the "last" position to which it has been electrically driven. For the purpose of illustration, assume that the cam is positioned such that the cam recess is aligned with the armature stop; the armature is now in free or de-energized position.
Figure 2
Upon application of power to the solenoid, a magnetic field is established corresponding to the polarity of the impressed voltage. The magnetic force attracts the armature, and the stray magnetic field causes rotation of the magnet to a position corresponding to the established polarity. The cam has thus been moved to a position where it is ready to block the armature from returning to its normal de-energized position. There is a very small clearance between the cam surface and the armature stop. This clearance permits the armature stop to "unlatch" more easily on re-actuation.
Figure 3
Upon removal of the power (i.e., switch in center-off position), the force attracting the armature is removed and the load is placed on the cam surface.
The unit is now in a position similar to that when normally energized. The assembly remains in this position with the power off until a voltage of proper polarity has been applied to the solenoid. With the application of voltage, force attracting the armature is re-established and the armature stop is removed from the cam surface. The permanent magnet re-orients itself in a position conforming to the established polarity.
FIGURE 4
A polarity reversal has been assumed. As the magnet rotates, it turns the cam to the original (de-energized position) where it cannot engage the stop. The travel extremes in either cam direction are governed by a positive stop which prevents the magnet assembly from rotating beyond the cam requirements.
