The mechanism is based on four-bar drag-link linkage ABCD consisting of l inks 1, 2 and 3. Triple crank 1 rotates about fixed axis A. Crank 2 has ring b encircling disk a. Connected to crank 1 and ring b are links 4, 5, 6 and 7. Links 3, 4 and 6 carry paddles c whose plane is perpendicular to the axis of these links.
$613$LW,ML$