Gear 3 and chain sprockets 1 and 5 are keyed to sleeve 2 which rotates freely about shaft 8. Sprocket 1 is driven by a reversing motor. Gear 4 and sprockets 7 and 6 all rotate freely on shaft 9. Gear 3 meshes with gear 4 and is rotated in one direction, while sprocket 5 is connected by a chain to sprocket 6 so that this sprocket rotates in the opposite direction to gear 4. When gear 4 is rotating in a definite direction, the clutch teeth d of sprocket 7 engage the clutch teeth a of gear 4 so that sprocket 7 rotates in the same direction as the gear. Here the flat faces of the teeth are in engagement. If the rotation of sprocket 1 is reversed, the action between the tapering surfaces of the backs of clutch teeth a and d of gear 4 and sprocket 7 shifts the sprocket axially so that clutch teeth b of the sprocket engage teeth f of sprocket 6. Driven now by sprocket 6, sprocket 7 continues to rotate in the same direction as before sprocket 1 was reversed. Thus sprocket 7 rotates in one direction regardless of reversals of sprocket 1. When sprocket 7 is shifted, the tops or lands of its clutch teeth may strike the tops of the teeth on gear 4 or sprocket 6, leading to a wedging or jamming action between glear 4 and sprocket 6. This wedging action is immediately relieved by axial motion of gear 4. This compresses spring 10 which returns gear 4 to its proper position when the clutch teeth engage properly.
$2941$CxG,ML$