Gear for Motive Power Engines.
Year: 1893

page_text: Date of Application, 17th Oct., 1893
Complete Specification Left, 24th Mar., 1894--Accepted, 25th Aug., 1894
PROVISIONAL SPECIFICATION.
Expansion Gear for Motive Power Engines.
EDWARD VERNON Engineer and JOSIAH JOHN GUEST Engineer both of
Alma Works Smethwick Staffordshire, and WILLIAM WALKER; Mechanical
Draughtsman of the same county residing in Smethwick do hereby declare the
nature of this invention to be as follows:-
Our invention consists in what is commonly known as trip gear, the period of
cut-off being automatically controlled by the governor, and dispensing with the
throttle valve.
In our arrangement of tripping gear, one of them is particularly applicable to
existing engines, and another arrangement can either be applied to engines having
"
"drop or "Cornish" valves at each end of the cylinder or cylinders provided
with valves of the Corliss type.
The first part of our invention, namely that appertaining to the application of
the trip gear to existing engines is in accordance with the following description.
We attach on the steam chest of the cylinder, a box containing a valve, preferably
of "Cornish" construction, and the said valve is made to beat twice during every
revolution of the engine.
The cover of the valve box is formed of an upright frame, and designed to carry
the various parts of the tripping gear hereafter named, and the said frame also
receives the governor of the "Pickering" type by preference, with its usual
driving gear.
A lever receives an oscillating motion from an eccentric on the main shaft or
other convenient part of the engine. This lever is keyed on to a sleeve, the said
sleeve having a suitable bearing or journal formed on the side of the upright frame.
At one end of the sleeve, (and by preference cast with it) is formed a vertical arm
of flat section which also oscillates.
The vertical arm is planed out and shaped to receive a sliding piece, the said
sliding piece having motion imparted to it to and fro by the direct action of the
governor.
At the top of the sliding piece and on its two vibrating sides, are mounted two
steel driving plates, and either one or the other of the driving plates (as the case
may be) is made to push outwards from the centre of the main frame, a trip latch
or detent lever. Each trip latch or detent lever is connected or pivotted to an
shaped lever, the lower limb of each lever extending to the centre of the drop
valve spindle, and engaging thereto by having toggles formed on the end of each
limb, and embraced by a square eye formed on the said drop valve spindle, whereby
a lifting motion is given to the drop valve spindle by each toggle alternately.
The action of the governor for the purpose of determining the period of tripping
is as follows:-The top of the sliding piece with its driving plates describe an
arc of a circle in their oscillating movement, and the detent latches are alternately
pushed outwards. The consequence of this is that the steel driving plates, namely
the driver and the driven, leave each other sooner or later, upon which the drop
valve is released, thereby returning rapidly but quietly to its seat, through the
intervention of the ordinary air "dash pot.'
The duration of time in the contact
of the respective driving plates, absolutely depends upon the height to which the
sliding piece with its driving plates shall be raised or lowered by the governor, as
for instance when the said governor shall be in its lowest position, the initial
engaging faces may be ths to ", giving a long range of cut-off, or on the other
hand, when the governor shall be at its maximum velocity or highest point, the

page_text: initial engaging faces may be only or even nil, thus controlling automatically
the speed of the engine in accordance with the load or fluctuations of boiler pressure.
The point at which either of the driving plates initially engage with either detent
latch or driven piece, always occurs at a time when the oscillating lever is in its
normal position or slowest travel, and consequently a minimum concussion, and
almost noiseless action'is maintained.
When either of the driving plates at the end of the vibrating lever are making
. their inward or return stroke, the detent latches are tilted up from their respective
fulcrums by either of the said driving plates on their top sides, the ends of the
said latches being inclined or bevilled on their bottom sides nearest to the engaging
faces, and fall back into place either by gravitation or spring force, for another
outward push, to enable the drop valve to be again lifted.
The said detent latches are prevented from falling too deep into gear by pads
or supports cast on the vertical frame, these pads supporting their respective detent
latches in their outward or inward movement, except when being tilted up by the
top of the driving plates already named.
1000
EDWARD VERNON.
JOSIAH JOHN GUEST.
WILLIAM WALKER.
I
COMPLETE SPECIFICATION.
Expansion Gear for Motive Power Engines.
EDWARD VERNON, Engineer, Alma Works, Smethwick, JOSIAH JOHN GUEST,
Engineer, Alma Works, Smethwick, and WILLIAM WALKER, Mechanical
Engineer, Smethwick, near Birmingham, 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 :-
Our invention consists in what is commonly known as trip gear, the period of
cut off being automatically controlled by the governor, and dispensing with the
ordinary throttle valve.
In our arrangements of tripping gear, one of them is particularly applicable to
existing engines, and another arrangement can either be applied to engines having
drop or "Cornish" valves at each end of the cylinder.
86
"
The first part of our invention, namely that appertaining to the application of
the trip gear to existing engines is in accordance with the following description.
We attach on the steam chest of the cylinder a box containing a valve preferably
of "Cornish" construction, and the said valve is made to beat twice during every
revolution of the engine.
The cover of the valve box is formed of an upright frame, and designed to carry
the various parts of the tripping gear hereafter named, and the said frame also
receives the governor of the Pickering" type by preference, with its usual
driving gear.
A lever receives an oscillating motion from an eccentric on the main shaft or
other convenient part of the engine-this lever is keyed on to a sleeve, the said
sleeve having a suitable bearing journal formed on the side of the upright frame.
At one end of the sleeve, (and by preference cast with it) is formed a vertical arm
of flat section which also oscillates. The vertical arm is planed out in a dovetailed
fashion, so as to receive a sliding piece, the said sliding piece having motion
imparted to it, to and fro by the direct action of the governor.
At the top of the sliding piece, and on its two vibrating sides, are mounted
two steel driving plates, and either one or the other of the driving plates (as the
case may be) is made to. push outwards from the centre of the main frame, a trip
latch or detent lever. Each trip latch or detent plate is connected or pivotted to

page_text: an shaped lever the lower limb of each lever extending to the centre of the
drop valve spindle, and engaging thereto by having toggles formed on the end of
each limb, and embraced by a square eye formed on the said drop valve spindle,
whereby a lifting motion is given to the drop valve spindle by each toggle
alternately.
"
The action of the governor for the purpose of determining the period of tripping
is as follows. The top of the sliding piece with its driving plates, describe an
arc of a circle in their oscillating movements, and the detent latches are alternately
pushed outwards. The consequence of this, is that the steel driving plates, viz.: the
driven and the driving leave each other sooner or later, upon which the "drop
valve is released, thereby returning rapidly but quietly to its seat, through the
intervention of the ordinary air "dash pot." The duration of time in the contact
of the respective driving plates absolutely depends upon the height to which the
sliding pieces with its driving plates shall be raised or lowered by the governor,
as for instance when the said governor shall be in its lowest position, the initial
engaging faces may be ths to "giving a long range of cut-off or on the other
hand, when the governor shall be at its maximum velocity or highest point, the
initial engaging faces may be only " or even nil, thus controlling automatically
the speed of the engine in accordance with the load, or fluctuation of boiler
pressure.
The point at which either of the driving plates initially engage with either
detent latch or driven piece, always occurs at a time, when the oscillating lever is
in its normal position or slowest travel, and consequently a minimum concussion
and almost noiseless action is maintained. When either of the driving plates at
the end of the vibrating lever are making their inward or return stroke the detent
latches are tilted up from their fulcrums by either of the said driving plates on
their top sides, the ends of the said latches being inclined or bevilled on their
bottom sides, nearest to the engaging faces, and fall back into place either by
gravitation or spring force for another outward push to enable the drop valve to
be again lifted. The said detent latches are prevented from falling too deep into
gear by pads or supports cast on the vertical frame, these pads supporting their
respective detent latches in their outward or inward movements, except when tilted
up by the top of the driving plates already named.
In order that our invention may be clearly understood, Figs. 1 and 2 illustrates
the mechanism as applied to existing engines.
The governor raises and lowers the sliding piece (T) by means of the lever (L)
and connecting link (C). Figs. 1 and 2 shew the governor at its lowest point or
slowest velocity, and the sliding piece (T) is therefore shewn with its driving
faces (F and F) in their highest position, and giving off the longest duration of
time for pushing outwards tangentially either of the detent latches (P and P').
This consequently permits either of the bell crank or L shaped levers (R and R¹)
to keep up the Cornish or "drop valve" (contained in box (M)) from its seat
during the longest period of time prior to its being released by the driving
faces (F and F) leaving the driven face of either of the detent latches (P and P¹)
at (G and G¹) in consequence of either detent latch (as the case may be) moving
outwards in a compound fashion namely horizontally, together with a vertical lift
of each detent latch end, due to the bevilled or inclined face at (R and R') having
to slide over the fixed pads (12 and 13), while the driving faces (F and F') describe
an arc of a circle in either one direction or another.
The highest position of the governor or when at its highest speed will depress
the sliding dovetailed piece (T) (shewn in section at Fig. 3) to a position clear of
the driven faces (G and G'), and under these conditions, no lift of the Cornish or
"drop valve" could occur, so that the range of cut-off would be brought to zero.
The eccentric on the crank shaft which imparts a vibrating or oscillating move-
ment to the lever (Y) Fig. 2, may have such a relation of angularity with that of
the engine crank, that ranges of expansion may be derived from ths of the stroke
of the engine, down to zero.

page_text: Fig. 1 shews each detent latch (P and P¹) resting on their respective pads 12
and 13, the oscillating lever (L³) being just upon the point of returning from
right to left in the direction of the arrow shewn at Fig. 1.
In this return motion from right to left, the top edge of the driving face as
shewn and marked (F¹) tilts up the end of the detent latch where inclined or
bevilled, as shewn and marked (A¹), and each detent latch (as the case may be)
fall into gear again from their respective fulcrums (29) and (30) by their own
gravitation, after the passing underneath of either of the driving faces (F) and (FI)
in either inward direction. This principle of tripping gear may be used for
operating Corliss or "drop" valves located at each end of the cylinder with slight
modifications in detail.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
Inclining or bevilling detent latches in order that a compound motion is
imparted to them by the action of a vibrating lever, namely an outward push of
such latches in an are of a circle at their fulcrums, and a lifting of the ends of
such latches at the same operation, caused by the bevilled or inclined faces of
each latch having to ride over a fixed pad, substantially as and for the purpose
hereinbefore described.
Dated this 19th day of March 1894.
EDWARD VERNON.
JOSIAH JOHN GUEST.
WILLIAM WALKER.