Abstract: An improved mechanism for converting the reciprocal motion of a drive member to pivotal motion of one or more levers includes a tooth member-receiving slot pair operatively connecting the drive member to the levers. The tooth member extends perpendicular to the axis of reciprocation of the drive member and the slot receives the tooth member in driving engagement therewith. Either the tooth member or the slot has a convex cam surface formed thereon and the other member of the pair has a flat cam-engaging surface. Rolling contact is thereby provided between the drive member and the levers when the drive member is actuated for reciprocal movement.