The V-cam slows down a drive's linear speed at the reversal points by reducing the pitch.
K-stops are positioned to contact the K-lever so that the rolling-ring assembly partially pivots just before reversal points, reducing the drive's linear speed before reversal takes place. This cushions the intensity of the change in direction. The H-lever slows the linear-drive speed before it reverses and permits gradual ramp up after reversal.