Year: 1886

page_text: Date of Application, 11th Oct., 1886.
Complete Left, 23rd Apr., 1887.
Complete Accepted, 24th May, 1887.
1, DUGALD CLERK, of 3 Ballochmyle Terrace, Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of this Invention to be as
follows, that is to say :-
My said Invention has for its object to improve the construction and action of gas
motors and to economise the gas employed therein.
In carrying out my Invention in the case of a single-acting engine-two open-ended
cylinders are employed hereinafter termed the motor cylinder and the pump, and are
placed parallel and as close together as conveniently possible, being fitted with pistons
or plungers connected in the usual way to cranks on a crank shaft. The pump crank
is placed so as to follow the motor crank at an angle of from 45 to 60 degrees of the
circle and the pump is arranged to draw in a combustible mixture of air and gas
which it compresses and transfers to the motor cylinder when the motor piston is at the
inner end of its stroke and during a short portion of its outward stroke. The passages
and valves of the motor are specially designed to avoid as much as possible any waste
of gas by clearance spaces; and the motor piston is within about a quarter of an inch
of the inner end of the cylinder when at the inner end of its stroke.
The ignition of the gaseous mixture is effected by means of any suitable one of the
various known igniting devices, just when the whole of a charge has been transferred
from the pump to the motor cylinder and the valve admitting it has been closed.
The exhaust takes place partly through a port which is in the side of the cylinder in a
position to be uncovered by the piston when at or near the outer end of its stroke ;
and the exhaust is completed through a port and valve at the inner end of the cylinder
during the inward stroke of the piston. By the partial exhaust at the forward port
the internal pressure is reduced so that the piston has scarcely more than atmospheric
pressure to contend with in expelling the used gases through the valve at the back
end; and at the same time the valve and exhaust passage at the back end will be as
little heated as possible by the expelled gases. The inlet and exhaust valves of the
motor cylinder which are moved by means of eccentrics are conical-seated disk valves,

page_text: and when closed the exhaust valve has its inner surface flush with the cylinder end;
they have springs applied to close them and air cushions to prevent knocking.
The pump piston during each outward stroke draws in gas and air in suitable
proportions, by preference, through a port closed by a conical-seated disk valve
provided with a spring and air cushion the gas entering through small holes round the
valve seat, with which construction the gas and air become thoroughly intermixed.
The gaseous mixture is compressed during the inward stroke of the pump piston and
towards the end of that stroke is transferred to the motor cylinder, as herein before
described.
The speed of the engine is regulated by governing devices acting as hereinafter
described. The lever of a centrifugal speed governor acts on a steel piece moving
with one of the eccentrics so as to rock a shaft through about a right angle, whereby
the inlet gas-and-air valve is prevented from opening and the gas cock is closed. The
pump is thereby prevented from drawing in a charge, and a partial vacuum is in
consequence formed by the outward stroke of its piston. At the same time the inlet
valve into the motor cylinder is kept closed the lever ordinarily opening it being
moved by the governor action so as not to move it, whilst the exhaust valve is kept
open in a similar way. Then, with the continued motion of the engine as long as its
speed is too great, the motor piston simply moves air in and out through the exhaust
ports, whilst the pump piston acts on the air in the pump as on a spring and without
drawing in or supplying to the motor cylinder any charge of combustible gaseous
mixture. As soon as the speed becomes lowered to its proper rate the governor
removes the parts which obstructed the action of the valves; and the ordinary action
of the engine proceeds, a fresh charge being taken in at every out stroke of the pump
piston and exploded at every outstroke of the motor piston.
Dated this Ninth day of October 1886

page_text: I, DUGALD CLERK, formerly of 3 Ballochmyle Terrace, Glasgow, in the County of
Lanark, North Britain, but now 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 ascer-
tained in and by the following statement, that is to say :-
My said Invention has for its object to improve the construction and action of gas
motors, and to economise the gas employed therein.
In carrying out my Invention in the case of a single-acting engine two open-
ended cylinders are employed hereinafter termed the motor cylinder and the pump,
and are placed parallel, and as close together as conveniently possible, being fitted
with pistons or plungers connected in the usual way to cranks on a crank shaft. The
pump crank is placed so as to follow the motor crank at an angle of from 45 to
60 degrees of the circle; and the pump is arranged to draw in a combustible mixture
of air and gas which it compresses and transfers to the motor cylinder when the
motor piston is at the inner end of its stroke and during a small portion of its
outward stroke. The passages and valves of the motor are specially designed to avoid
as much as possible any waste of gas by clearance spaces and the motor piston is
within about a quarter of an inch of the inner end of the cylinder when at the inner
end of its stroke.
The exhaust takes place partly through a port which is in the side of the cylinder
in a position to be uncovered by the piston when at or near the outer end of its stroke;
and the exhaust is completed through a port and valve at the inner end of the cylinder
during the inward stroke of the piston. By the partial exhaust at the forward port
the internal pressure is reduced so that the piston has scarcely more than atmospheric
pressure to contend with in expelling the used gases through the valve at the back
end; and at the same time the valve and exhaust passage at the back end will be as
little heated as possible by the expelled gases. The speed of the engine is regulated
by governing devices, which when the speed is too great prevent the admission of the
combustible mixture into the pump, the piston of which then forming a partial vacuum
acts as though drawing out a spring, the motor piston at the same time drawing in
and expelling air through the exhaust valve which is kept open.
And in order that my said Invention and the manner of performing the same may
be properly understood I hereunto append five sheets of explanatory drawings to be
hereinafter referred to and representing a gas motor as made with one modification of
my improvements.
Figures, 1, 2, 3, on sheets, 1, 2, 3, of the accompanying drawings are respectively a
plan, a side elevation, and an end elevation of the gas motor. Figures, 4, 5, 6, on
sheet, 3, are diagrams showing the pump and motor pistons in different positions.
Figure, 7, on sheet, 4, is an enlarged section showing part of the valve gear at the
back of the motor and is taken as at right angles to figure, 8, on the same sheet and

page_text: which is an enlarged horizontal section as taken through the axes of the motor and
pump cylinders. Figure, 9, on sheet, 5, is an enlarged sectional side elevation of the
after part of the motor; and figures, 10, 11, 12, on the same sheet, are sections
explanatory of various parts of the valves and passages. In these drawings the same
reference letters and numerals are used to mark the same or like parts wherever they
are repeated.
The engine shown in the drawings is made with two horizontal open-ended cylinders,
a motor cylinder, M, and a pump cylinder, P, the inner ends of these cylinders being
surrounded as usual by water spaces, W, and having working within them plunger
pistons, M 1, and P 1, which are connected in the ordinary way to cranks, MC, and, PC,
on a shaft, S, carried in the ordinary way and provided with a flywheel. The motor
crank, MC, is, in the modification shown in the drawings, placed 45 degrees of the
circle in advance of the pump crank, P C. In the diagrams, figures, 4, 5, and 6,
three positions of the parts are shown whilst a compressed charge is being transferred
from the pump, P, to the motor cylinder, M. In figure, 4, the pump piston has
moved in compressing the charge to about half stroke the motor piston being then
within about an inch of its cylinder bottom at which point the valve between the two
cylinders opens (the exhaust valve having just closed) and the pressure in both
cylinders becomes equal. In figure, 5, the motor piston has gone full home and the
pump piston has still some distanco to move inwards. In figure, 6, the pump piston
is full in and the motor piston just in the position of having received the full charge,
ignition being about to take place.
As the pump piston, P 1, performs its outward stroke it draws in air through a
conical-seated check valve, 20, which has its face flush with the inner end of the
pump, P, and which closes again by the action of a spring, 21, concussion in closing
being prevented by an enlargement, 22, on the valve spindle being cushioned by air
confined in a socket in the casting. The opening of the valve, 20, also admits the
gas which issues through a number of holes in the valve seat from an annular
channel, 23, with which the gas supply pipe communicates. This construction of
valve and seat insures the thorough intermixture of the gas and air in the pump, l.
These inlet valve details are shown in horizontal section in figure, 8, and in vertical
section in figure, 10, and are contained in a casting, 24, which can be removed by
itself for examination or repair, heing fixed in a socket formed for it in the end
casting, E, which contains various passages and valve details and is bolted to the back
end of the main casting containing the cylinders, M, P.
The charge passes from the pump, P, to the motor cylinder, M, through a passage
consisting of two parts, 25, 26, indicated by dotted lines in figure, 7, and shown in
section in figure, 12, as taken through the passage, 25, 26. The ports of these
passages are in the sides of the cylinders, M, P, and close to their ends; and the
passages are made as short as possible. A plain disk valve, 27, hereinafter termed
the communicating valve, is fitted between the two parts, 25, 26, to keep the passage
from the pump, P, to the motor cylinder, M, closed excepting at the time when the
charge has to be transferred from one to the other. The valve is arranged to be
closed by a spring, which is strong enough to resist the pressure due to compression,
its spindle, 28, having on it a piston block, 29, which prevents concussion by cushioning
on air in a socket formed in the casting, 30, containing the valve, and which is
removable from the end casting, E, and main casting into which latter it partly
extends.
The used gases are partly exhausted from the motor cylinder, M, through a port, 31,
indicated by dotted lines in figure, 8, and which the piston, M 1, passes over at the
outer end of its stroke. The remaining used gases are expelled by the inward stroke
of the piston, M 1, through a passage at the inner end of the cylinder and controlled
by a disk valve, 32, which when not pushed or held open as hereinafter described is
closed by a spring, 33, applied to its spindle, 34. Concussion is prevented, as in the
case of the other valves, by a piston block, 35, on the spindle cushioning air in a socket
in the casting, 36, containing the valve, and which is fixed in the end casting, E.
The communicating valve, 27, the igniting valve, 63, and the exhaust valve, 32,

page_text: are worked by means of two eccentrics on the crank shaft, S, the rods, 37, 38, of
these eccentrics being jointed to rams or bars, 39, 40, fitted to slide horizontally in
guides formed in the end casting, E. The rams, 39, 40, act by encountering and
pushing backwards levers which return by the action of the springs applied to the
valves when the rams return forwards. One ram, 39, acts on a lever, 41, which is
connected to and moves the exhaust valve, 32, and the other ram, 40, acts on a
lever, 42, which is connected to and moves the communicating valve, 27. The
levers, 41, 42, have jointed to them bars, 43, 44, fitted to work in guides in the end
casting, and it is on the ends of these bars always kept square by the guides that the
rams, 39, 40, act in moving the levers. The valve spindles, 34, 28, are connected to
the levers, 41, 42, by long joint pins, 68, extending to apertures in the casting, E,
so that they can be easily withdrawn when it is necessary to get at the valves.
The speed of the engine is regulated by governing devices acting as hereinafter
described. An ordinary centrifugal governor, 45, by its rod, 46, moves a small
lever, 47, which has fixed in it two pins projecting in opposite directions. On
these pins rest two hooked rods, 48, 49, jointed to two bellerank levers, 50, 51, and
extending over a steel catch projection, 52, fixed on one of the eccentric rods, 38, or
on the ram, 40, moved by it." When the speed becomes too great the governor
depresses the end of the lever, 47, to which it is attached, and the hooked rod, 48, is
thereby lowered so that its hook becomes engaged by the catch, 52, when moving
towards the shaft. The hooked rod is thereby made to draw over the outer bell-
crank, 50, and to rock a horizontal shaft, 53, on which the bellcrank is fixed. The
rocking shaft, 53, by a lever, 54, on it moves a lever, 55, which by its inner forked
end acting on a collar, 56, adjustably fixed on the spindle of the pump inlet valve, 20,
holds that valve firmly to its seat thereby preventing a fresh charge of gas and air
from entering the pump. The stoppage of the supply of gas is further insured by a
valve, 57, shown in the section, figure, 10, this valve being pressed towards its seat
by a spring, and being ordinarily held open by a cam-shaped piece, 58, jointed to a
lever, 59, on the rocking shaft, 53. The piece, 58, acts on a nut on the valve spindle;
and when the gas supply is to be stopped in obedience to to the governor action, is
drawn down so as to let the valve, 57, close. Another lever, 59, on the rocking
shaft, 53, acting between springs on a stop rod, 60, makes that rod get in the way of
a projection on the exhaust-valve lever, 41, when opening the valve and prevents the
valve from closing again until the speed decreases to its proper rate. At the same
time that the rocking shaft, 53, is moved as hereinbefore described, an arm of the
bellcrank, 50, by a rod, 61, moves a slide, 62, fitted to the end of the bar, 44, of the
lever, 42, so as to place a recess facing the end of the ram, 40, and thereby prevents
the ram from moving the lever and through it opening the communicating valve, 27.
Whenever the speed decreases to its proper rate the governor raises the end, to
which it is attached, of the small lever, 47, thereby lifting the hooked rod, 48, last
acted on and lowering the other hooked rod, 49, which is next drawn towards the
shaft, S, by the catch, 52, and moves the bellcrank, 51, into the position in which it
is shown in figure, 9. The two belleranks, 50, 51, are connected together by their
short arms, and the bellerank, 51, when moved as last described also moves the other
bellcrank, 50, back into the position in which it is shown in figure, 9, and thereby
causes the return of the various parts to their normal positions or functions.
As long as the action of the valves is not interfered with by the governor a fresh
charge is taken in at every outstroke of the pump piston and exploded at every out-
stroke of the motor piston.
Any suitable one of the various known igniting devices may be used, and I make
no claim to the arrangement adopted in the engine shown in the accompanying
drawings; but I add a brief description in order that the parts connected with it and
shown in the drawings may be understood. The igniting valve, 63, is a plunger
pressed upon a seat by a spring, and when it is moved from the seat it allows the
explosive mixture in the motor cylinder, M, to get access to a red-hot tube which
ignites it. The red-hot tube is within a small open-topped casing, 64, in which it is
heated by an ignited gas jet. The igniting valve, 63, is moved by one end of a lever, 65,

page_text: centered so as to move horizontally and acted on at its opposite end by a third
plunger, 66, placed above the two, 39, 40. This plunger, 66, is made with two projec-
tions to be pushed by blocks fixed to the plungers, 39, 40, and is connected by a
link, 67, to the valve lever, 65, the plunger, 66, working in a guide in the casting, E,
and having on its back end a pin which projects up through a slot, and has the link, 67,
jointed upon it. The plunger, 39, gives the movement for effecting ignition; and
afterwards the other plunger, 40, again opens the ignition valve to allow of any excess
of pressure in the red-hot tube passing into the motor cylinder, M, when the exhaust
is taking place therefrom.
Having now particularly 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 :—
1-Arranging and combining parts to form a gas motor substantially in the
improved manner hereinbefore described and shown in the accompanying drawings.
2-Arranging the communicating valve and the passage between the pump and
motor cylinder substantially in the manner herein before described whereby the
clearance or passage space in both pump and motor cylinder is made very small.
3-Arranging a single lift valve termed the communicating valve to close both the
outlet from the pump and the inlet into the motor cylinder substantially as herein-
before described.
4 The combination of an exhaust port uncovered by the motor piston when at the
outer end of its stroke with an exhaust port and valve at the inner end of the motor
cylinder substantially as hereinbefore described.
5 The combining and arranging of parts which in obedience to the action of the
governor when the speed becomes too great, modify the operations of the valves
substantially in the manner and for the purposes hereinbefore described.
Dated this Twenty-second day of April 1887.
EDMUND HUNT,
Applicant's Agent.