Link 1 rotates about fixed axis A and is the carrier of planet gear 3 which meshes with fixed sun gear 4. Planet gear 3 carries pin a which consecutively engages straight radial slots d of Geneva wheel 2. Geneva wheel 2 rotates about fixed axis B and its slots d are located symmetrically at angles of 90° between the axes of adjacent slots. Carrier 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 carrier 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 planet gear 3 about axis A is T=tᵣ+tᵢ. Gears 3 and 4 have equal pitch radii and therefore point D of pin a describes a cardioid. In the position shown, point D is at the point of the cardioid most distant from axis A. To each revolution of driving carrier 1, planet gear 3 rolls around sun gear 4 and pin a turns Geneva wheel 2 through 90°. Carrier 1 and Geneva wheel 2 rotate in opposite directions.
$2636$PG,GW$