Dual plunger solenoid

A solenoid is provided in which the armature unit includes a primary plunger and a secondary plunger arranged in telescopic association one with the other and disposed so that the secondary plunger, having both a smaller mass and a smaller air gap than the primary plunger, initially draws in the primary plunger against the anvil without altering the stroke of the primary plunger. The coaction between the two plungers materially reduces the electric energy required to operate the solenoid. While not limited in its application to any particular form of magnetic circuit or to any particular size of magnet, the invention is especially useful in connection with mechanism in which a miniature solenoid is required, and also when it is required to employ a solenoid in which the armature stroke is relatively large and the power requirement must be small.