When plate 1 oscillates about fixed axis A-A in a plane perpendicular to that of the drawing, ratchet-tooth rack 2 is shifted by spring 5 to the right in fixed guides d-d as soon as tooth a, rigidly attached to plate 1, swings out of engagement with a tooth of rack 2. In its motion to the right, rack 2 shifts angle plate 3 whose tooth b remains in engagement with a tooth of rack 2 as plate 1 swings beyond the plane of the drawing. Spring 4 returns plate 3 to the initial position when plate 1 swings to its other extreme position, in front of the plane of the drawing, and tooth b swings out of engagement with the tooth of rack 2, but tooth a engages the next rack tooth.
$2789$RG,FD$