When eccentric 1 rotates about fixed axis A, the right end of lever 2, whose left end is connected to tie-rod 5 by turning pair B, oscillates about axis B as if it were a fixed axis. If pin a, rotating together with shaft 3, turns lever 4 clockwise about fixed axis C, then end b of the lever will engage right end c of lever 2 and prevent its oscillation. After this, rotation of eccentric 1 will oscillate the left end of lever 2 together with tie-rod 5. Spring 6 holds lever 2 in contact with eccentric 1.
$1687$LC,4L$