Plate cam 1 turns about fixed axis A and acts on symmetrically located pins (followers) 5 which slide in fixed guides B. When cam 1 is turned clockwise, pins 5 push against buttons d of hinged clamps 2, turning the clamps about fixed axes C to clamp workpiece 3. To release the workpiece, cam 1 is turned counterclockwise, after which springs 4 return clamps 2 to the initial unclamped position.
$3229$CmL,GC$