Eccentric 1 rotates about fixed axis A of frame member (tub) 3. Shoe 2 has frame b with slot c whose width equals the diameter of eccentric 1. Frame b also has slot a along which pin B of eccentric 1 slides. When eccentric 1 rotates about axis A it alternately elevates and shifts shoes 2 and frame member 3 forward or backward.
$1452$LG,FD$