IMPROVEMENTS IN GAS ENGINES, APPLICABLE IN PART TO OTHER USES
Year: 1878

page_text: LETTERS PATENT to Richard Hallewell, of Blackburn, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN GAS ENGINES,
APPLICABLE IN PART TO OTHER USES."
Sealed the 1st November 1878, and dated the 4th May 1878.
PROVISIONAL SPECIFICATION left by the said Richard Hallewell at tho
Office of the Commissioners of Patents on the 4th May 1878.
RICHARD HALLEWELL, of Blackburn, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN GAS ENGINES, APPLICABLE IN PART TO OTHER USES."
My Invention relates in the first place to the class of gas engines having two
pistons fitted in one cylinder, one piston being driven outwards by the explosion,
and being held during the acting stroke of the other piston, and it is to means for
holding the first-named piston that the first part of my Invention principally
relates.
In one arrangement I mount two blocks or gripping pieces upon a lever in such
a manner as that each block shall be capable of an adjusting movement upon a
fulcrum. The piston rod passes between the two faces of the said blocks. The two
fulcra of the blocks are preferably not both in line with the fulcrum of the said
lever, the effect being that when the lever is moved in one direction the blocks are
tightened upon the piston rod, and when moved in the other direction the piston
rod is released. The lever is moved to grip the piston rod by means of a spring or
load, or of the weight of the parts, or by both means, and is moved to release the
piston rod by means of a cam, or by suitable means. The said blocks may bo
faced with wood, lignum vitæ, leather, or other suitable material, or be formed of
wood or other suitable material. The arrangement is applicable to safety appa-
ratus for hoists, and to other uses.
In a second arrangement the piston rod slides between a fixed face or bearing.
surface, and the face of a wedge gripping piece, or between two wedge gripping
pieces. A fixed abutment is formed with a face which is inclined to the same

page_text: extent as the wedge, and between the two inclined faces rollers are interposed, the
wedge rolling upon the rollers when moved to and fro. When the wedge is moved
in one direction by means of a spring the piston rod is gripped, and when moved
in the other direction the piston rod is released..
In the second place my Invention relates to the supply of gas. A hollow plug
is fitted to revolve or rock in a sufficiently gas-tight manner within a shell which
is formed or mounted within a part through which the air is conveyed. The air
from the inlet valve is divided into comparatively broad and thin streams which
flow on each side of the said shell. The said shell is formed with a number of per-
forations, or with slits which extend to the interior of the said plug. The gas is
supplied to the interior of the plug, and flowing through the perforations mingles
with the streams of air. The supply of gas is regulated by turning the plug
within the shell by hand, or by means of a governor so as to decrease the area for
the passage of gas through each perforation.
According to a third part of my Invention I provide the cylinder of a gas engine
with an air inlet valve which admits air during a part of the stroke of the engine,
a mixture of air and gas being subsequently admitted. When the explosion takes
place air is driven through a valve, or through valves, into an air chamber, whence
it is admitted to the space on the other side of the piston, or is driven directly into
such space, and being compressed, acts upon the piston in aid of the vacuum or
partial vacuum produced by the explosion to effect the return stroke of the piston.
At the next outward stroke the air thus used is ejected through a valve which is
opened at the required times.
In the fourth place I form gas engines with air chambers which communicate
freely with, or are formed by extensions of the ends of the cylinders to which the
gas is admitted. In one arrangement the gaseous products of the explosion fill the
chamber, and the explosive mixture is admitted through the side of the cylinder
so as to enter between the said products and the piston, or is admitted at the bottom
or end of the cylinder.
In another arrangement an inlet opening provided with an inlet valve is formed
in the side of the cylinder and admits air into the chamber and cylinder after the
explosion, and on the return stroke of the piston, air, with the products of the
explosion, is permitted to escape through a slide valve at the end of the chamber or
cylinder, leaving the chamber filled with air, more or less mixed with the said
products. The explosive mixture is admitted by the said slide valve which in some
cases may also admit air as in the case of the aforesaid inlet valve. I prefer to
compress the said mixture into a receiver by means of a pump, the action of which
is controlled by the governor, the said receiver feeding the engine with gas at a
high pressure.
In a fifth part of my Invention I compress the explosive mixture by means of
the piston of the engine, or by means of a supplementary piston. The slide valve
which admits the mixture to the cylinder and effects its discharge, admits the
mixture in the first place to the space above the piston or the outer end of the
cylinder. When the piston moves outwards the mixture is compressed and is
driven into a receiver which supplies the engine. I control the working of the
slide valve by means of the governor which also opens an air inlet valve at the
times when the explosion is not required to take place. When I employ a supple-
mentary piston I arrange it to slide to and fro in an extension of the cylinder
below, or at the rear of the working piston, and to draw in and compress the
explosive mixture. I work the said supplementary piston by means of a cam on
the crank shaft and a re-acting spring, or by other suitable means
In the sixth place, in double piston gas engines, I fit a cylindrical block or shell
to slide in an extension of a gas engine cylinder, and I connect it by means of a
shaft or shell with the working piston. The said block is provided with one or two
studs or trunnions, and the cylinder is formed with one or two side slots or openings.
The trunnion or each trunnion passes through an opening and is connected by
means of a suitable connecting rod with a crank on the crank shaft. The said

page_text: opening, or each opening, is planed to receive a sliding block, or suitable slides are
formed on or fixed to the cylinder or framing.
In one arrangement, applicable more particularly to vertical engines, the crank
shaft passes across one side of the cylinder and may revolve in bearings attached
thereto, the fly wheel being on the said crank shaft, or a fly wheel shaft may be
applied on the other side of the cylinders and be driven by multiplying gearing.
In another arrangement, also applicable principally to vertical engines, an internal
spur wheel revolves on a stud fixed to the side of the cylinder, and is provided
with a crank pin with which the connecting rod engages. The said internal wheel
gears with a pinion fixed on the fly-wheel shaft which is mounted in bearings at the
side of the cylinder and passes across the said side.
In the seventh place, in double piston gas engines, I make the exhaust port of a
"tee" shape, one limb of the tee being horizontal in the case of a vertical cylinder,
the other limb being vertical or thereabouts. When the loose piston is released it
passes the horizontal limb of the port, and thereby greatly restricts the area for
discharge. When closely approaching the working piston the products of com-
bustion have to escape through the vertical limb which is comparatively narrow, so
that the speed of the said piston is checked.
Another part of my Invention relates to the slide valves for admitting and
firing the explosive gases. A slide block works between the valve face and a
covering plate. In the valve face is the port leading to the cylinder, and on one
side of this is a port conveying the gas and air, and on the other side is a gas pas-
sage. In the covering plate is a port, in the mouth of which is an igniting jet. In
the slide block is a flame chamber and also a recess. When the valve is in one
position the said recess conveys the explosive mixture into the cylinder, and at the
same time gas flows from the said gas passage into the flame chamber and is ignited
by the igniting jet. When the valve is moved into another position the flame
chamber is brought into communication with the port leading to the cylinder and
the explosion takes place.
In a remaining part of my Invention I employ a hinged arm, preferably made of
steel, to carry a screw which is employed to press the valve cover against the slide.
valve of a gas engine. The said hinged arm is prevented from turning on its
hinge pin by means of a hinged abutment which, when moved away from the
hinge joint of the said arm, ermits it to be turned up or over so that the cover
can be readily removed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Hallewell in the Great Seal Patent Office on the 4th
November 1878.
RICHARD HALLEWELL, of Blackburn, in the County of Lancaster, Engineer..
"IMPROVEMENTS IN GAS ENGINES, APPLICABLE IN PART TO OTHER USES."
My Invention relates, in the first place, to the class of gas engines having two
pistons fitted in one cylinder, one piston being driven outwards by the explosion,
and being held during the acting stroke of the other piston, and it is to means for
holding the first-named piston that the first part of my Invention principally
relates.
In one arrangement I mount two blocks or gripping pieces upon a lever in such
a manner as that when the lever is moved in one direction the blocks are tightened
upon the piston rod, and when moved in the other direction the piston rod is
released.
In a second arrangement the piston rod slides between a fixed face or bearing
surface and the face of a wedge-gripping piece or between two wedge-gripping
pieces.
In the second place my Invention relates to the supply of gas, and has for its
object to obtain a more perfect mixture of the gas and air.
According to a third part of my Invention I provide the cylinder of a gas engine
with an air inlet valve which admits air during a part of the stroke of the engine,
a mixture of air and gas being subsequently admitted, the action being described
herein-after.
In the fourth place in double-piston gas engines I fit a cylindrical block or shell
to slide in an extension of the cylinder, and connect it with the working piston.
In the fifth place, in double-piston gas engines I make the exhaust port of a
"tee" shape.
A sixth part of my Invention relates to the slide valves of gas engines.
According to a remaining part of my Invention I employ a hinged arm to carry a
screw which is employed to press the valve cover against the slide valve of a gas
engine.
In order that my Invention may be more readily described I will now refer to
the Drawings which I have attached hereunto, and which are for the most part one-
quarter of the full size.
The first part of my Invention is illustrated in Sheet 1 of the said Drawings,
wherein Fig. 1 represents an elevation of a portion of a vertical gas engine, partly
in section, and Fig. 2 is a plan view of the arrangements for holding the piston rod,
Fig. 3 being a side elevation of the same.
In the said Figs. A is the piston which is driven upwards by the explosion of the
gases, as is usual, and b is the piston rod, which in the example is rectangular in
cross section.
A lever B is hinged to a bracket c, which is fixed or formed upon the
cylinder cover, and upon studs d, d', fixed to this lever are mounted friction blocks
or gripping pieces e, e. Each block is free to swivel upon its stud, so as to adjust
itself to the piston rod, and is or may be faced with wood, lignum vitæ, leather, or
other suitable material; or the blocks may be made of wood or of a material which
will be more suitable than metal. The stud d' is lower than a line drawn through
the fulcrum at B and the stud d. The effect of this is that when the free end of
the lever is lowered the blocks are caused to grip the piston rod. When the lever
end is raised the piston rod is released. By varying the positions of the studs the
gripping action may be adjusted, and, if preferred, the fulcra of the blocks may be
so arranged as that the gripping action may result from a raising of the lever end.

page_text: A cam C on the crank shaft D acting on a bowl which is mounted upon the lever
end raises the said end at the required times, and thereby releases the piston rod.
The lever falls to grip the rod by reason of its own weight, and, if preferred, a
spring or load may be employed to render the action of the lever more prompt.
The arrangement may also be adapted to horizontal gas engines, and is also appli-
cable to safety apparatus for hoists and to other uses.
A second arrangement for effecting the same object is illustrated in Sheet 2,
wherein Fig. 6 represents a vertical section of the upper end of the cylinder of a
gas engine. In this example the piston rod b slides between a taper gripping piece g
and a fixed face or bearing surface formed on a projection f on the cylinder cover.
On a projecting abutment f¹ is formed a surface which is inclined to the same angle
as the opposed side of the piece g, and between this surface and the piece g are
interposed a number of rollers. A lever h is mounted upon a fulcrum, and when
raised acts upon a pin on the piece g and raises the same, when the piston rod will
be free to slide. When the said lever is lowered the piece g falls, being at the same
time pressed downwards by a spring i, and is wedged between the rollers and the
piston rod, thereby firmly holding the said rod. One roller or less than the indicated
number may be used. The lever his acted upon at the required intervals by a
suitable cam. The piece
may be faced with leather or other suitable material.
In the example the sides of the space between the parts fand f' are closed by
plates, one of which is represented by Fig. 8, and are strengthened by bolts j, j.
The second part of my Invention is illustrated in Sheet 3, wherein Fig. 11 is a
section of a gas valve, and Fig. 12 a view taken at right angles to Fig. 11. In
these Figs. k is a shell which is bored to receive a hollow plug l, and is fixed in a
chamber m. Perforations, slots, or ports are formed on each side, both in the plug
and in the said shell. The gas supply is admitted at n, and flows through a passage
into the interior of the plug. The supply of air is admitted through a port o, and
flows through the chamber m, being divided into two streams by the shell k, each
stream flowing past the perforations on one side of the shell. The gas issues from
the plug in a number of streams which mingle with the passing currents of air.
The supply of gas is regulated by turning the plug within its shell, either by hand
when required, or by means of a governor, whereby the area for the flow of gas
through each perforation is increased or decreased as required.
The third part of my Invention is illustrated in Sheet 4, wherein is represented a
plan, partly in section, of a horizontal gas engine. In the cylinder F are formed
ports p which communicate with a passage leading to a chamber 9. The passage
opening from the cylinder into this chamber is closed by a hinged valve, which is
pressed to its seating by a spring. A passage leads from this chamber into an
annular chamber r. In one side of this chamber is a port which is alternately'
opened and closed by means of a slide valves, which is operated by a cam F. upon
the crank shaft. When the said valve is in the indicated position the said port is
closed and a passage is opened through a port t leading from the outer end of the
cylinder to an escape pipe u. When the valve is moved into its other position the
passage leading to u is closed and a passage leading from the chamber r to the port t
and thence to the outer end of the cylinder, is opened. To the lid of the valve box
or chamber q is fixed a spring vacuum valve which is arranged to open and to admit
air to the chamber q, and as a consequence to the outer end of the cylinder in the
event of the formation of a vacuum therein.
g
The supply of air and gas is admitted to the inner end of the cylinder by means
of a slide valve G, which is operated by a cam H on the crank shaft. The said
valve receives gas through a passage v, and air through a passage w.
When the
piston commences its outward stroke the valve is in such a position as that the
passage vis closed, and air alone is drawn into the cylinder. At a suitable point
in the stroke the valve is moved to admit gas which enters the cylinder along with
air during a suitable period in the stroke.

page_text: When the mixture is fired the air first admitted and the gaseous matters are
driven through the valve chamber into the chamber r, and are imprisoned by the
closing of the valve q.
When the piston commences its inward stroke the valve 8 is shifted to admit the
compressed gas to flow from r into the outer end of the cylinder, and the piston
then performs its inner stroke by reason of the pressure on one side and the vacuum
on the other. During the next outward stroke the gases in the outer end of the
cylinder are permitted to escape at u.
The forms and arrangements of the valve passages and chambers may be varied,
and in some cases the valve s may be dispensed with, the communication between
the chamber r and the outer end of the cylinder remaining open at all times.
>
The fourth part of my Invention is illustrated in Sheets 1 and 2.
In Sheet 1, Figs. 1 and 4, a block or piston H is fitted to slide within the
cylinder, and is connected by a shell, shaft, or connecting piece I with the working
piston J. The parts H, I, and J may be cast or formed in one piece or not, as
preferred. In the side of the cylinder a slot x is formed, and through this slot
The sides of the slot x are
passes a trunnion y, which is fixed to the block H.
planed, and a block is fitted to slide up and down in the said slot. The trunnion y
is connected by the rod K with the crank pin L, which is fixed to a fly wheel on
the crank shaft D. In the example the said crank shaft revolves in a bearing or in
bearings, which is or are carried by the upper end of the cylinder. As the piston J
slides to and fro the motion is transmitted through the block H and rod K to the
crank shaft, the connecting piece I being of such a length as that the piston J
when at the end of its downward stroke does not reach or pass the upper end of
the slot.
In some cases a slot may be formed in each side of the cylinder, and the block
H be connected with the cranks by means of two rods. This method of transmit-
ting motion from the piston to the crank shaft may also be applied to horizontal
engines.
In Sheet 2, Figs. 9 and 10, the connecting rod K is coupled to a crank pin,
which is fixed to an internal spur wheel M, which is fitted to revolve on a stud
which is fixed to the cylinder. The said wheel gears with a pinion which is fixed
on the fly wheel shaft N, which is fitted to revolve in a bearing or in bearings fixed
to or formed in or on the side of the cylinder. In this arrangement the speed of
the fly wheel shaft is accelerated.
The rod K is coupled to a block or part corresponding to the block H in Sheet 1.
In some cases the wheel M may be an external spur wheel, and may gear with a
spur wheel or pinion on the fly wheel shaft.
The fifth part of my Invention is illustrated in Figs. 1 and 4, Sheet 1, wherein
2 is a "tee" shaped exhaust port formed in the side of the cylinder.
During the descent of the loose piston A the gases escape through the whole of
the port, but when the said piston nears the end of its inward stroke it passes the
horizontal limb of the port and thereby greatly restricts the area of the passage,
and as during the remainder of its stroke the gases have to escape through the
vertical limb, which is comparatively narrow, the speed of the piston is checked.
The sixth part of my Invention is illustrated in Figs. 11 and 12, Sheet 3, wherein
E is a sliding block, which works between the valve face and a covering plate a'.
In the valve face is a port 61 leading to the cylinder. Above or on one side of this
port is a port leading into the chamber m, or into a passage, through which the gas
and air are admitted by any suitable means. On the other side of the port is a
passage c', which is supplied with gas.
In the covering plate al is an opening in which is a gas jet d³, and in the valve
block is a flame chamber e¹ and a recess g¹. When the valve block is moved down-
wards from the position indicated the recess g¹ connects the port 6 with the port,
through which the explosive mixture is admitted, and at the same time gas flows

page_text: from c¹ into the flame chamber, and is ignited by the jet d². When the valve is
moved upwards the flame chamber is brought into communication with the port b¹;
and the explosion takes place. The terms upward and downward are used only for
convenience of description.
The remaining part of my Invention is also illustrated by the Figs. in Sheet 3.
The valve cover a² is pressed against the slide valve or block by means of a screw h¹,
which works in a nut formed in or fixed to one end of an arm k¹, which is preferably
made of steel in order that it may have an amount of spring. The said arm is hinged
at to a fixed part, and to the same part or to a suitablo part is also hinged an
abutment m¹. A projection n' formed on the arm bears against the said abutment,
and the arm is thereby prevented from turning on its hinge or joint when the screw
is tightened up.
When it is desirable to remove the cover the screw is slackened and the abut-
ment is turned back, and the arm, may then be turned out of the way so that
the cover can be readily removed. The abutment may be arranged to slide or be
otherwise arranged to be movable..
.
Having now fully set forth and indicated the nature of my said Invention, and
means whereby the same may be carried into effect, I would have it to be under-
stood in conclusion that I do not claim the parts referred to in my Provisional
Specification as the fourth and fifth parts of my Invention, as I have excluded such
parts herefrom, and that I claim,―
First. The various combinations and arrangements of parts acting substantially
as and for the purposes set forth and indicated herein-before, and in and by the
accompanying Drawings.
Secondly. The lever and swivel blocks formed and acting to grip or hold a piston
rod or a rod or bar at the required times or intervals, substantially as set forth and
indicated.
Thirdly. The wedge and the roller or rollers, and inclined abutment for gripping
the piston rod, substantially as and for the purpose set forth and indicated.
Fourthly. The valve formed to deliver the gas into the current or currents of
air in a number of streams, and to regulate the volumes of such streams, substan-
stantially as set forth and indicated when describing the second part of my
Invention.
Fifthly. Providing the cylinder of a gas engine with a receiving chamber, into
which the gases are driven from one end of the cylinder through a passage or
through passages closed by a back pressure valve or by back pressure valves, and
admitting the compressed gases froin such receiving chamber into the other end of
the cylinder to aid in effecting the return stroke of the piston, substantially as set
forth and indicated.
Sixthly. Admitting air into the cylinder prior to the admission of the explosive
charge, and providing a valve or valves, through which the gases or part of the
gases may be driven by the explosion in order to some extent to obtain a vacuum
within the cylinder.
Seventhly. The method of connecting the crank pin, with the piston, substantially
as set forth and indicated when describing the fourth part of my Invention.
Eighthly. The internal wheel, geared, with a spur wheel on the fly wheel shaft
of a gas engine, for transmitting an accelerated motion to the said shaft.
Ninthly. The "tee" shaped exhaust port, substantially as and for the purpose
set forth and indicated.
Tenthly. The slide valve and connected parts formed, arranged, and acting sub-
stantially as and for the purposes set forth and indicated when describing the sixth
part of my Invention.
And lastly. The hinged arm, in combination with a hinged or movable abutment,

page_text: substantially as and for the purpose set forth and indicated when describing the
last part of my Invention.
In witness whereof, I, the said Richard Hallewell, have hereunto set my hand
and seal, this Second day of November, in the year of our Lord One
thousand eight hundred and seventy-eight.
RICHARD HALLEWELL. (L.S.)
Signed and sealed by the said
Richard Hallewell in the
presence of
EDWARD K. DUTTON,
Agent to the Patentee,
St. Ann's Churchyard,
Manchester.