Link 5 of four-bar linkage ABCD has gear segment b meshing with segment c of link 6. Link 5 has pins d that engage slots a of link 6. When crank 1 rotates about fixed axis A, link 6 oscillates with dwells about fixed axis E. To avoid impacts in the gearing, gear segments b and c are brought into and taken out of mesh by the action of pins d on slots a of link 6. The motion and dwell periods of link 6 can be varied by changing the distance between turning pairs C and D. This is done by moving slider 3 along screw 4. It is necessary, at the same time, to change the angles at which pins d are set with respect to line CD. Concentric surfaces f of link 5 engage concave surfaces e of link 6 to prevent unintentional rotation of link 6 during its dwell periods.
$1758$GL,D$