Model: M08 Differential Screw Mechanisms with Two Spur-Gear Pairs
The classic differential screw mechanism of model M-7 uses the difference in pitch between the two screws on the same shaft to translate a measuring pointer. In model M-8, the screw is moved by a spur-gear pair at one end and by another pair attached to a keyed sliding joint shaft at the other end. The two gear pairs have teeth ratios of 62:14 and 60:15 at the screw end and rotating slider ends, respectively. The two pinion gear wheels are driven by the same crank. The screw is thus moved proportionally by the difference in rotation of the two gears. These devices were used in precision measurement equipment.
Francis Moon 2004-07-00
- Reuleaux, Kennedy : Kinematics of Machinery (§151, Figure 383, pp. 546-547, 1876)