STEAM – ENGINE REVERSING – GEAR

To compensate for the lap always formed on plain side valves,
the slot is not formed across the center s of the eccentric, but is
placed across the center t of the crank shaft e, away from the
center a distance equal to the lap on one end of the valve, so that
the eccentric, when in its central position, will move the valve
just enough to compensate for the lap, while any change of position
in the eccentric will cause the steam-ports to be opened and steam
to be supplied to the piston during a part of the stroke
corresponding to the extent of the eccentric’s displacement
from its central position.

To shift the eccentric while in motion, I employ a
diagonally-grooved traveler, k, or key with inclined grooves 1
form, ed in its top, the key being fitted to the groove m or seat
in the shaft e, and passing through suitable notches n, cut
opposite the seat in the collars b and c. One side of the slot h,
opposite the seat m, is formed with inclined teeth o, which fit,
the groove’s 1 in the traveler k, and any longitudinal movement
of the traveler therefore causes a transverse movement of the
eccentric between the collars b and c, any transverse movement of
the traveler being  prevented by the sides of seat m and by
its fitting the notches in collars b and c.

A clutch ring, p, is fitted loosely to the shaft e, and secured
by a screw or pin, q, to the end of the traveler, which projects
from the collars b,c, and a groove, r, formed in the periphery of
the ring, furnishes the means to move the traveler when the shaft e
is in motion, as is usual with all revolving clutches.

The engine has a seven eight inch bore,
¹3_/8 stroke. The fly wheel is
4¹/₂ in diameter and
⁷/₈‘ face. The crank shaft is one half
inch in the bearing and nine sixteenth inch between the bearings.
The governor is a dummy. The base is 9 inches long and 6 inches
wide. He operated the engine on compressed air for
demonstrating.

The Pipestone is interesting itself. It can be worked the same
as iron and takes a high polish. It is kind of dark maroon
color

By this construction the engine can be reversed without the use
of any parts extraneous to the eccentric and the few fittings
described, and the operation of the engine and its valve is equally
per-feet in whichever direction it revolves, while the facility
with which the stroke of the eccentric can be varied affords the
most convenient means of changing the cut off point of the valve
and adjusting- the supply of steam exactly to work the engine has
to perform. This is especially desirable when the speed has to be
greatly varied, as in the starting, stopping, and backing of steam
vessels, or when the load upon the engine is frequently changed, as
in hoisting, towing’, etc.