Fig. 3402.

Each steam valve is provided with a link motion that may be used for varying the point of cut off (and therefore the expansion) as well as for reversing purposes.

The link motions are all shifted from one shaft, which may be operated by hand or by steam, the construction being as follows:

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Fig. 3403.

For shifting by hand, the wheel w is operated, its shaft having a worm driving the worm wheel g, [Fig. 3403], which operates rod h, and through the lever j and rod k shifts the link l, one pair of eccentric rods being shown at n and p.

VOL. II.TRIPLE EXPANSION MARINE ENGINE.PLATE XXXVII.
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Fig. 3404.

The shaft of the wheel w is, however, a crank shaft, and at m is a small engine, which may be connected or disconnected at will to shaft w. The lever j operates a shaft r in [Fig. 3404], which connects (by a rod corresponding to rod k in [Fig. 3403]) to each link motion; hence all the links reverse together, and the ratio expansion of one cylinder to the other cannot be varied, or in other words, the point of cut off will be alike for each cylinder, let the link motion be shifted to whatever position it may.