[1440]. Gab lever for throwing the eccentric out of gear and thus stopping the engine.
[1441]. Sector and link reversing motion for oscillating engine; sometimes a shifting eccentric is used instead of link motion, as [No. 1443].
[1442]. Reversing sector link motion for an oscillating engine; the valve is operated from the link, the angle of which is altered by the hand lever, there is therefore no lead to the valve.
[1443]. Shifting eccentric and balance sometimes used for reversing instead of double eccentrics and link; the loose eccentric is carried round in either direction by a stop piece on the shaft, fixed so as to give the correct lead both ways.
[1444]. Murdoch’s variable expansion gear (see Mechanical World, September 29th, 1888) has one eccentric which operates a double arm lever, the outer end of which moves a sliding fulcrum along the valve rod lever, so that the leverage of the valve rod lever varies at different parts of the stroke. The sliding fulcrum is attached to a radius rod.
[1445]. Proell’s automatic expansion gear. Shown applied to special double beat valves, but is sometimes applied to a special throttle valve, and is then applicable to any ordinary engine. The action of the governor alters the lap of the catches upon the ends of the valve levers, thus varying the time that the valves are kept open; the catches are centered on an oscillating T lever, operated from an eccentric on the main shaft.
[1446]. Marshall’s valve gear, driven by one eccentric on crank shaft. The sector rocking centre is moved along the curved slot to reverse the engine, giving similar motion to the valve rod as in the case of the ordinary link reversing gear [No. 1436].
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[1447]. The Bremmé valve gear with single eccentric; the valve rod is operated by a lever and bent connecting rod from the end of the eccentric rod; the latter is constrained to move in an arc by a three-link attachment to a fixed bearing behind the eccentric rod and a movable one at the right-hand end of the horizontal link. To reverse, the arm and sector are turned to the dotted position by the worm and hand wheel shaft.