Box 25, Pavilion, New York 14525
From the valve-gear side of the engine, the valve-gear shaft is
driven by a pair of spiral gears from the main engine shaft, and
its speed is, of course, one-half the speed of the latter. The
exhaust-valve is operated by a cam, while the inlet valve is
actuated by means of an eccentric.
The valve-gear is shown in detail in the figure below, and it
will be observed that the regulation is effected by means of a
release gear by which the inlet valve is disengaged and closed at
varying points of the stroke, to suit the load. To some extent, the
cylinder is scavenged with pure air in order to prevent, as much as
possible, any back-firing due to slow-burning mixtures.
The operation of the gear is as follows:
The inlet valve I is opened by means of the
rocker R when the pick-blade P on
the end of the eccentric rod E, lifts the end of
the rocker arm, and the valve becomes opened more and more, until
the roller D rides up on the trip block
T, the position of which is controlled by the
governor. It is evident that the further the trip block is moved to
the right the earlier in the stroke the valve will trip.
As soon as the main inlet valve opens, air will be admitted to
the cylinder from the air port, for scavenging purposes. The gas
valve G has a sliding fit on the main valve stem
and is held closed by the spring Z, until the
collar C, which is solid on the valve spindle,
moving down, forces the valve to open against the spring pressure
back of it. The position in which the valve is drawn is such, it
will be observed, that the main valve is opened to some extent for
the admission of air, and the collar C is just
touching the hub of the gas valve to effect its opening, in unison
with the main valve, as the latter is further opened.
S is the main valve spring, the function of which
is to close the main inlet valve, and to hold it closed against the
partial vacuum that will be created in the cylinder at light
loads.
For the cushioning of the valve, in seating, a cushioning-pot
and piston are provided at O. Means are also
provided in the gas and air ports, whereby the proportioning of the
air and gas may be regulated to suit any kind of fuel that may be
used.