Abstract: A solenoid electromagnet includes a movable core spaced from a fixed core, a spring urging the movable core away from the fixed core, an operation rod having a plurality of detent projections, a picker having an axially fixed connection with the movable core, and a catch having an axially fixed connection with the fixed core. The operation rod is slidably inserted in the movable core, and the picker as well as the catch is engageable with the detent projections of the rod. The stroke of the movable core causes the picker to push the operation rod by the engagement of the picker with the detent projection. At the same time the catch engages the detent projection to hold the operation rod at its position, thereby enabling successive advancement of the operation rod according to the strokes of the movable core.