ot matter whether it is partially
unbalanced to prevent leakage or not, the fact that it is not entirely
balanced prevents it reaching the ideal valve.
[Illustration: Fig. 5]
This valve, Fig. 5, differs from the others also in this particular,
that the exhaust takes place at the end of the valve instead of under
the arch. Two eccentrics are used, the one for the main valve being
fastened to the shaft and the other riding loosely upon it and
connected to the fly wheel governor, by which it may be turned forward
or back as the load requires. The three points of lead, or admission
and exhaust and compression, are fixed and independent of the changes
and cut off. The motion of the main eccentric is given to a rocker
arm, the pivot of which is at the bottom, and from the upper end the
valve rod transfers the motion to the valve without reversing the
motion, as is done sometimes in the slide valve to overcome the
effects of the angularity of the connecting rod. The action of the
rocker arm, therefore, so far as the main valve in the Buckeye is
concerned, is no different than that which would occur if no rocker
arm intervened. The motion of the cut off eccentric, through its
eccentric rod, is given to a rocker rocking in a bearing in the center
of the main rocker arm (see Fig. 6). The motion of this eccentric is
reversed, so far as the cut off valve is concerned, and when the cut
off eccentric is moving forward, the cut off valve is being pushed
back. The main valve rod is hollow, and the cut off valve rod passes
through it.
[Illustration: Fig. 6]
The cut off eccentric can be placed in any position to cause it to cut
off as desired, and by drawing the valve forward, by increasing the
angular advance of the eccentric, the cut off valve is caused to reach
and cover the steam passage in the main valve earlier in the stroke.
Instead of being ahead of the crank, the main eccentric in this
arrangement follows the crank, on account of the exhaust and steam
edges being exactly opposite from those in the ordinary slide. What is
the steam edge of the common slide is in this the exhaust edge, and
what is the exhaust edge in the common valve is the steam edge in this
one. The valve, therefore, must be moved in the opposite direction
from what is ordinarily the case, the main eccentric being not 90 deg.
behind the crank. It has a rapid and full opening just the same, for
it is at this point behind the crank, or ahead of it, that t
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