Link (bolt) 1 slides in fixed guides a-a. Link 2 turns about fixed axis A. When bolt 1 moves from one extreme position to the other, link 2 remains with its end b pressed tight against one side d until bolt 1 reaches the position of maximum tension of spring 3. After this, link 2 is quickly flipped over to its other extreme position with end b against the other side d.
$2132$EL,SE$