[1456]. Variable cut-off valve on the back of the main slide, the rod of which can be revolved by hand or from the governor to vary the opening of the cut off valves.
[1457]. A plan to effect the same object but by a cylindrical cut off valve.
[1458]. English’s expansion gear. Two eccentrics. The expansion valve has no lap, and the gear gives a constant relative motion to both valves.
[1459]. Tappet gear, sometimes used for water-pressure engines, &c.
Section 80.—SPRINGS.
[1460]. Open spiral spring for tension.
[1461]. Close spiral spring.
[1462]. Open spiral spring for compression.
[1463]. Open spiral spring (square thread) for compression.