9) Long-dwell Geneva drive: This Geneva arrangement has a chain with an extended pin in combination with a standard Geneva. This permits a long dwell between each 90° shift in the position of the Geneva. The spacing between the sprockets determines the length of dwell. Some of the links have special extensions to lock the Geneva in place between stations.
11) Internal groove Geneva drive: This arrangement permits the roller to exit and enter the driving slots tangentially. In the position shown, the driving roller has just completed indexing the Geneva, and it is about to coast for 90° as it goes around the curve. (During this time, a separate locking device might be necessary to prevent an external torque from reversing the Geneva.)
15) Parallel guidance drive: The input crank contains two planet gears. The center sun gear is ﬁxed. By making the three gears equal in diameter and having gear 2 serve as an idler, any member ﬁxed to gear 3 will remain parallel to its previous positions throughout the rotation of the input ring crank.
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