Improvements in Combined Governor and Trip Expansion Gear for Steam or other Fluid Pressure Engines.
Year: 1893

page_text: Date of Application, 13th Mar., 1893
Complete Specification Left, 13th Dec., 1893-Accepted, 27th Jan., 1894
PROVISIONAL SPECIFICATION.
Improvements in Combined Governor and Trip Expansion Gear for
Steam or other Fluid Pressure Engines.
I, WILLIAM CAMERON of Maryport in the County of Cumberland Mechanical
Engineer do hereby declare the nature of this invention to be as follows :-
This invention relates to improvements in combined governor and trip expansion
gear. The governor and trip expansion gear is self contained and is readily
applicable to existing non-expansion engines.
In my invention an eccentric actuates a lever the ends of which are armed with
two steel faces. The arms of this lever make an angle of approximately 45° with
the vertical or 90° with each other.
These steel faces alternately come into contact with two fingers which are hung
on pins secured in each end of two obtuse angled levers.
These obtuse angled levers are carried on pins placed equidistant from and on
opposite sides of their respective pins or fulcra are coupled to the admission valve,
so that the valve is opened twice during one complete revolution of the engine.
The free ends of the fingers are under the control of the governor and the
position of the governor balls determines the amount of contact between the steel
faces and the fingers, which are released and the valve closed sooner or later
according to the position of the governor balls.
The valve may be closed by springs or other suitable means and cushioned by
a dash-pot. On the return of the oscillating lever that finger which has just been
released falls into gear by gravity and is ready again to transmit the movement of
the eccentric to the valve.
Dated this 10th day of March 1893
WM. CAMERON.
COMPLETE SPECIFICATION.
Improvements in Combined Governor and Trip Expansion Gear for
Steam or other Fluid Pressure Engines.
I, WILLIAM CAMERON of Maryport, in the County of Cumberland, Mechanical
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 :-
This invention relates to improvements in combined governors and trip gears.
The governor and trip gear is self contained and is readily applicable to existing
non-expansive engines.
In my invention an eccentric actuates a lever the ends of which are armed with
two steel faces.
The arms of this lever make an angle of approximately 45° with the vertical
or 90° with each other.
These steel faces alternately come into contact with two fingers which are hung
on pins secured in one end of each of the two obtuse angled levers. These obtuse
angled levers are carried on pins placed equidistant from and on opposite sides of
the vertical centre line and these ends of those obtuse angled levers lying on the
opposite sides of their respective pins or fulcra, from, those on which the fingers
are carried are coupled to the admission valve.

page_text: The free ends of the fingers are under the control of the governor therefore the
position of the governor balls determines the amount of contact between the steel
faces of the obtuse armed lever and those of the fingers, the fingers being
released and the valve closed sooner or later according to the position of the
governor balls.
In order that my invention may be better understood I will proceed to describe
the annexed drawing.
Fig. 1 is a sectional elevation of my combined governor and trip gear.
Fig. 2 is a modification of the trip gear.
The same reference letters are used for similar parts in Figs. 1 & 2 the action
of the parts in both being precisely similar.
The lever a is shewn by dotted lines and receives an oscillating movement from
an eccentric. It will be understood that when driven by the same eccentric which
operates for instance the slide valve of the engine to which the gear is applied the
gear will give a range from zero to of the piston stroke and when driven by an
independent eccentric from zero to of the stroke.
The lever a is secured to a spindle b on which is keyed the double armed lever d.
On each of these arms is mounted steel faces e & e₁. The arms of this lever make
an angle of approximately 45 degrees with the vertical.
These steel faces e & e₁ come each into contact once during one complete
oscillation of the lever a, with the steel faces mounted on the levers or
fingers f&f 1.
These fingers or levers hang on pins which are secured in the ends of two
obtuse angled levers g & J1. The levers 9 & 91 are fulcrumed on pins & hq
and their ends other than those on which the levers & h₁ hang are coupled
through suitable connections to the valve I so that during one complete oscillation
of the lever a, i.e. during one revolution of the engine the valve I is twice opened
to admit steam.
1
The free ends of the levers f& fi lie on a pin k which is directly under the
control of the governor and as the position of the pin is raised or lowered the
steel faces on the levers or fingers f & fi engage more or less deeply with the steel
faces e & e, on the lever d and consequently the time during which the valve I is
held open and the cut off is varied, according to the position of the pink which
depends on the position of the governor balls.
On the faces being released the valve is closed by means of a spring and cushioned
by a dash-pot in the usual manner.
On the valve closing the parts fall into the position shewn in the accompanying
drawing, with the exception of that lever or finger which has just been released and
this immediately falls into position by gravitation on the return of the oscillating
lever .e. when the lever has reached the centre of its oscillation.
The modification of the gear which is shewn in Fig. 2 consists in using straight
levers or fingers f& f₁ in place of curved ones as in Fig. 1 and arranging
the various centres to suit the slightly altered conditions when results precisely
similar to that obtained from the arrangement shewn in Fig. 1 will be attained.
It will be readily understood that although the pin k is shewn as being under the
control of a governor, it can easily be arranged so as to raised or lowered,
and the point of cut off varied, by hand without departing from my invention.
The governor I use is of the spring type and may be made to give any desired
variation from the mcan speed.
Having now described and ascertained the nature of my said invention and in
what manner the same is to be performed, I declare that what I claim is
1st. In a trip expansion gear two levers or fingers each armed with steel faces
and having curved or straight free ends the said free ends lying freely on a pin or
pins substantially as and for the purpose set forth.
2nd. The combination in a trip expansion gear of two levers or fingers each
armed with steel faces and having curved or straight free ends, a pin or its

page_text: equivalent the position of which can be varied either by a governor or by hand,
two obtuse angled levers carrying the before mentioned levers or fingers, and an
oscillating two armed lever fitted with steel faces substantially as shewn and
described in connection with Figs. 1 & 2 of the annexed drawing.
3rd. The combination of a governor and a trip gear consisting of two fingers or
levers, a pin or its equivalent two obtuse angled levers and an oscillating doubled
armed lever substantially as shewn and described in connection with Figs. 1 & 2 of
the annexed drawing.
Th: 11th December 1802
WM. CAMERON.