Connecting rod 2 of four-bar linkage ABCD has collar b encircling round eccentric 1 which rotates about fixed axis A. Lever 4 turns about fixed axis D and is connected by turning pair E to slider 6 which moves in slot d of valve stem 5. Stem 5 reciprocates in fixed guides p-p. When eccentric 1 rotates about axis A, lug a of connecting rod 2 describes a connecting-rod curve in which it turns lever 4 to raise valve stem 5 . At a certain point in its path lug a slips off lever 4 and the valve is pushed downward by spring 7.
$1453$LG,FD$