Rocker arm 4 of four-bar linkage DCBA turns about axis A and has paddle a at its end. When crank 1 rotates about fixed axis D, paddle a slides along the bottom of bowl b. The bowl bottom is spherical with the centre at point A. Lever 2 with weight 3 serve to hold paddle a against the bottom of bowl b. The bowl is rotated about vertical axis y-y by a drive which is not shown.
$886$LW,FD$