Improvements in Gas Engine Governors and Valve Gear.
Year: 1892

page_text: Date of Application, 19th Mar., 1882
Complete Specification Left, 18th Jan., 1893-Accepted, 18th Feb.,
1893
PROVISIONAL SPECIFICATION.
Improvements in Gas Engine Governors and Valve Gear.
I, Dugald CLERK, of Driffold Villa, Manor Hill, Sutton Coldfield, in the
County of Warwick, Engineer, do hereby declare the nature of this invention to
be as follows:-
Part of my invention consists of a novel form of gas engine governor in which a
pawl is oscillated to and fro from an eccentric or other suitable moving part of a
gas engine. The pawl engages tooth by tooth the teeth of a ratchet wheel and its
stroke is preferably constrained to follow a circular or curved path by means of a
link. The pawl is held down to engage the teeth by a spring and the spring is so
arranged that its tension is capable of adjustment. The ratchet wheel rotates a
gas valve, or operates a gas valve by its rotation so that in one position of the
ratchet wheel the gas is closed and in another position it is free to pass to the
cylinder. When the speed becomes excessive the centrifugal force of the mass of
the pawl, which is made somewhat heavy, causes it to rise from the ratchet wheel
on its back or free stroke and it rises to such distance that it cannot fall in time to
engage the next tooth of the ratchet wheel, and so the wheel remains stationary
and the gas valve remains closed. When the speed moderates the pawl falls into
its tooth and supplies gas to the engine again.
Sometimes I arrange the ratchet wheel so that certain teeth are higher than
others, that is at a greater distance from the centre of the wheel, and this prevents
the pawl from rising high enough to escape the high teeth by straining the spring
to a greater tension. In this manner I cause the pawl in governing to select certain
teeth and always gear with others with the object of leaving the gas valve always
in a closed position when the pawl ceases to act.
Instead of using centrifugal force to cause the pawl to rise I may reciprocate in
a straight or almost straight path and cause the pawl to rise from the teeth on its
free stroke by the momentum of its moving weight and the rise will then occur as
the pawl is completing its free stroke. If it does not fall in time it will not engage
the next tooth and so governing will be effected.
Sometimes I arrange a catch piece or hook to hold the pawl up whenever it
rises due to excess speed, and to prevent it from falling till a stroke is completed,
when the said hook is knocked away.
My pawl governor may be applied to rotate a circular valve for operating the
inlet of gas and air to the engine and the exhaust of the burned gases from the
engine, and in this case I arrange a single lift valve between the cylinder and
the said rotating valve so that the pressure of the compression and explosion is
taken by this valve. The pawl is oscillated by an eccentric or other attachment,
and rotates the valve; while the valve or its spindle, by a cam operates the lift
valve, opening to the cylinder, so that exhaust and compression strokes alternate
and the "Otto" cycle is performed. The pawl governor may act on this rotating
valve to leave it stationary to cut off gas when speed becomes excessive.
Dated this 18th day of March 1892.

page_text: COMPLETE SPECIFICATION.
Improvements in Gas Engine Governors and Valve Gear.
I, DUGALD CLERK, of Driffold Villa, Manor Hill, Sutton Coldfield, in the
County of Warwick, Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
Part of my invention consists of a novel form of gas engine governor in which
a pawl is oscillated to and fro from an eccentric or other suitable moving part
of a gas engine.
Referring to the accompanying sheet of drawings
Figure 1 is a section showing my pawl governor and ratchet wheel with spring
adjustment.
Figure 2 is a section through the gas cock showing the gas passage closed.
Figure 3 is a section showing my rotating cock actuating a lift valve.
The pawl A engages tooth by tooth the teeth of a ratchet wheel C and its stroke
is preferably constrained to follow a circular or curved path by means of a link B.
The pawl is held down to engage the teeth by a spring M and the spring is so
arranged that its tension is capable of adjustment. This is done by the lever E
and adjusting screw F. The ratchet wheel rotates a gas valve D (Figure 2) or
operates a gas valve by its rotation so that in one position of the ratchet wheel as
at Figure 2 the gas is closed, and in another position it is free to pass to the
cylinder. When the speed becomes excessive the centrifugal force of the mass of
the pawl A, which is made somewhat heavy, causes it to rise from the ratchet
wheel C on its back or free stroke and it rises to such distance that it cannot fall
in time to engage the next tooth of the ratchet wheel and so the wheel remains
stationary and the gas valve remains closed. When the speed moderates the pawl
falls into its tooth and supplies gas to the engine again.
Sometimes I arrange the ratchet wheel so that certain teeth are higher than
others, that is, at a greater distance from the centre of the wheel and this prevents
the pawl from rising high enough to escape the high teeth by straining the spring
to a greater extent. In Figure 1 the ratchet wheel C is of smaller diameter over
the teeth KK, than over those L L so that the pawl A rises off the teeth K K
when governing.
In this manner I cause the pawl in governing to select certain teeth KK and
always gear with others L L with the object of leaving the gas valve always in a
closed position when the pawl ceases to act.
Instead of using centrifugal force to cause the pawl to rise 1 may reciprocate in
a straight or almost straight path and cause the pawl to rise from the teeth on its
free stroke by the momentum of its moving weight and the rise will then occur as
the pawl is completing its free stroke. If it does not fall in time it will not engage
the next tooth and so governing will be effected. Sometimes I arrange a catch
piece or hook to hold the pawl up whenever it rises due to excess speed, and to
prevent it from falling till a stroke is completed when the said hook is knocked
away.
My pawl governor may be applied to rotate a circular valve as in Figure 3 for
operating the inlet of gas and air to the engine, and the exhaust of the burned
gases from the engine, and in this case I arrange a single lift valve H between the
cylinder and the said rotating valve so that the pressure of the compression and
explosion is taken by this valve. The valve D is the circular valve and it has
suitable ports. The pawl is oscillated by an eccentric or other attachment and
rotates the valve, while the valve or its spindle by a cam G operates the lift
valve H opening to the cylinder, so that exhaust and compression strokes alternate
and the Otto cycle is performed. The pawl governor may act on this rotating
valve to leave it stationary to cut off gas when speed becomes excessive.

page_text: When I operate in this manner I prefer to cut eight teeth on the ratchet wheel,
and I apply a pawl below the said wheel so connected that it moves the wheel on
the said idle stroke of the pawl A.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be perforined, I declare that what 1
claim is :-
:-
1. In gas and like engines, a governor comprising an oscillating pawl operating a
ratchet wheel, the pawl so arranged that when speed exceeds the normal the pawl
rises out of the teeth and does not engage the teeth until speed falls again.
2. In gas and like engines, a pawl governing apparatus as claimed in the pre-
ceding claim together with a ratchet wheel having teeth of less diameter or radius
to cause the pawl to miss certain teeth while governing, substantially as and for
the purposes herein before described.
3. The pawl and ratchet wheel operating and governing gear hereinbefore
described and illustrated at Figures 1 and 2 of the drawings.
4. The pawl and ratchet wheel operating and governing gear hereinbefore
described and illustrated at Figure 3 of the drawings.
Deted this 17th day of January 1893.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicant.