Pin wheel 1 rotates about fixed axis A and carries pin a of oval cross section which consecutively engages radial slots d of Geneva wheel 2. Geneva wheel 2 rotates about fixed axis B and its slots are located symmetrically at angles of 90° between the axes of adjacent slots. The side walls of each slot are not parallel to each other. Pin wheel 1 has concentric locking surface b which engages concave locking surfaces e of Geneva wheel 2 to prevent its unintentional rotation during its idle periods. When pin wheel 1 rotates continuously at uniform velocity, Geneva wheel 2 rotates intermittently at nonuniform velocity with four rotation periods tᵣ and four idle periods tᵢ. The time of one revolution of pin wheel 1 is T=tᵣ+tᵢ. Pin a contacts one side of slot d, turning Geneva wheel 2 through an angle of 90°. At the same time, pin wheel 1 turns through an angle of 60°. The mechanism operates without impact, in the same way as if slots d were not radial. Pin wheel 1 and Geneva wheel 2 rotate in opposite directions.
$2643$PG,GW$