Crank 1 of four-bar linkage KDEF rotates about fixed axis K. Point A of pin a on connecting rod 2 describes a connecting-rod curve of which portion q-q is used for the entrance of pin a into slot d and for turning Geneva wheel 3 about fixed axis C. Straight radial slots d are located symmetrically with angles of 90° between the axes of adjacent slots. Gear 4 is rigidly attached to crank 1 and, through intermediate gear 5, drives gear 6 which rotates about fixed axis B and is rigidly attached to a member having concentric locking surface b. Surface b engages concave locking surfaces e of Geneva wheel 3 to prevent its unintentional rotation during its idle periods. When crank 1 rotates continuously at uniform velocity, Geneva wheel 3 rotates intermittently at nonuniform velocity with four rotation periods tᵣ and four idle periods tᵢ. The time of one revolution of crank 1 is T=tᵣ+tᵢ. Geneva wheel 3 turns through an angle of 90° to each revolution of crank 1. By properly selecting the lengths of the links of four-bar linkage KDEF a connecting-rod curve can be obtained providing for sufficiently uniform velocity of rotation of Geneva wheel 3 during its rotation periods tᵣ.
$2635$PG,GW$