Patent ID: 10767400

Abstract:
An advancing/retreating movement mechanism 1 of an advancing/retreating member includes: a lifter 3; a coil spring 5; a lock pin 7 that limits the movement of the lifter 3; a case 2 that accommodates the lifter 3 and the coil spring 5; an advance/retreat position control mechanism 9 that controls an advance position, a retreat position, and a reciprocating movement of the lifter 3; and a receiving seat 11 that receives the coil spring 5 so that the lifter 3 is biased. The receiving seat 11 is arranged in a rearward position side of the lifter 3. An engaging part 27a engaging the lock pin 7 is arranged to the lifter 3. When the lifter 3 moves to the retreat position, the engaging part 27a moves to a rearward side beyond the receiving seat 11 and moves to a position where the engaging part 27a can be engaged with the lock pin 7. Therefore, the size of the advancing/retreating member in a protruding/withdrawing direction can be made small.