Proximity switch with snap lock

A proximity switch for monitoring the operating position of a mechanical device and selectively opening and closing an electrical circuit in response thereto, the switch comprising:

• an outer shaft slidably mounted in a housing;
• an inner shaft slidably mounted within the outer shaft;
• a magnet on a left end of the inner shaft that urges the inner shaft leftward when a target is proximate a left end of the housing, wherein “left” and “right” mean toward a first and second end of the housing respectively;
• a first spring that urges the inner shaft rightward;
• a second spring that urges the outer shaft rightward or leftward in response to respective rightward or leftward movement of the inner shaft;
• and
• a locking mechanism actuated by an engagement pin on the inner shaft that prevents movement of the outer shaft until the second spring is compressed, then releases the outer shaft to snap rightward or leftward as urged by the second spring, snapping a movable electrical contact on the outer shaft between first and second positions relative to a fixed electrical contact in the housing.

A proximity switch for monitoring the operating position of a mechanical device and selectively opening and closing an electrical circuit in response thereto, the switch comprising:

• an inner shaft that slides linearly within an outer shaft, wherein the outer shaft slides linearly within a housing;
• a magnet on a left end of the inner shaft, wherein “left” and “right” mean toward a first and second end of the housing respectively;
• a first spring urging the inner shaft rightward;
• movable electrical contacts on a right end of the outer shaft, and fixed electrical contact in the housing that are fixed relative to the housing;
• an engagement pin on the inner shaft that releases a left locking claw from a left locking post on the outer shaft when the inner shaft moves leftward, and releases a right locking claw from a right locking post on the outer shaft when the inner shaft moves rightward, wherein each locking claw pivots on a respective axle that is fixed relative to the housing;
• and
• a second spring that is compressed by relative movement between the inner shaft and the outer shaft;
• wherein leftward movement of the inner shaft causes the second spring to urge the outer shaft leftward, then the engagement pin releases the left locking claw, releasing the outer shaft to snap leftward, snapping the movable electrical contacts into a first position relative to the fixed electrical contacts;
• wherein rightward movement of the inner shaft causes the second spring to urge the outer shaft rightward, then the engagement pin releases the right locking claw, releasing the outer shaft to snap rightward, snapping the movable electrical contacts into a second position relative to the fixed electrical contacts;
• and
• wherein the left and right locking claws are urged by respective third and fourth springs to engage the left and right locking posts respectively unless released by the engagement pin.