Movement No. 59 presents a compact and practical two-speed gear transmission system that uses a combination of belt drive and spur gearing to deliver two selectable output speeds to a lower shaft — plus a neutral disengaged state — by shifting a single drive belt across three pulleys. The three pulleys are arranged side by side on the input side. The leftmost pulley is a loose idler — when the belt rides here, no power is transmitted to any gear, placing the system in neutral. The middle pulley is fixed directly to the shaft of a small pinion gear. When the belt is placed on this middle pulley, the small pinion is driven and meshes with the output gear on the lower shaft — because the pinion is small relative to the output gear, this produces a slow output speed with high torque, as the large gear ratio reduces the speed significantly. The rightmost pulley is fixed to a hollow shaft that runs concentrically around the pinion shaft — independently of it — with a large spur gear fixed to its far end. When the belt is shifted to this rightmost pulley, the hollow shaft and its large spur gear are driven instead. Since the large spur gear is bigger than the small pinion, it meshes with the output gear at a more favorable ratio, producing a faster output speed proportional to the diameter difference between the two input gears. This elegant two-speed arrangement — neutral, slow, and fast — is directly related to Movement No. 58’s three-speed system, but simplified to two active speeds using one solid shaft and one hollow shaft, making it ideal for simpler machine tools and light industrial equipment requiring basic two-speed operation.
59. For transmitting two speeds by gearing. The band is shown on the loose pulley-the left-hand one of the lower three. The middle pulley is fixed on the same shaft as the small pinion, and the pulley to the right on a hollow shaft, on the end of which is fixed the large spur-gear. When the band is on the middle pulley a slow motion is transmitted to the shaft below; but when it is on the right-hand pulley a quick speed is given, proportionate to the diameter of the gears.