IMPROVEMENTS IN GAS ENGINES
Year: 1885

page_text: I, JAMES ATKINSON, Engineer, of No 3, Nassington Road, Hampstead, London,
N.W. do hereby declare the nature of my invention for IMPROVEMENTS IN GAS
ENGINES to be as follows:-
I construct my improved gas engine with a separate single acting pump, and a
separate single acting working cylinder.
The pump is constructed with as little clearance space as is compatible with
safety, and always pumps an uniform mixture of gas and air; it is fitted with
suitable suction valves and governor, but has no delivery valve necessary; its piston
is operated by a crank pin or other connection with the main shaft, so that it
completes its compressing stroke a little after the working piston has completed its
exhausting stroke.
The working piston has only such clearance space when its piston has completed
its exhausting stroke, as is necessary to provide for the unavoidable deposit that
takes place here; just before the completion of this stroke, the exhaust valve being
closed, communication is opened between the pump and the working cylinder
through the slide, and the compressed combustible mixture passes through the slide
from the pump into the working cylinder during a portion of the working stroke,
when it is cut by the slide and ignited, also through the slide, by means of an
igniting tube heated externally, thus causing a working pressure on the working
piston during the remainder of the working stroke. The consumed gases are
exhausted through an exhaust valve operated by means of an eccentric on the
crank shaft.
The slide is of special construction. It is very similar to the circular slide
described and illustrated by me in Letters Patent No 3039. A.D. 1884, but instead
of moving continuously, it is moved intermittantly by means of a ratchet pawl
engaging into ratchet teeth on its periphery. The slide has as many ports cut
through it as there are ratchet teeth and is moved one tooth for each revolution of
the engine; it moves in a plane parallel to the plane in which the crank pin
revolves, and is operated directly by an eccentric or cam on the main shaft.
The ratchet pawl is not allowed to fall on the slide when passing over a tooth,
but drops onto a piece of leather or other suitable substance so as to deaden noise,
also the stroke of the eccentric is only just so long as to cause the pawl to clear the
tooth, and the pawl is so arranged that its own momentum on being reversed causes
it to fall so as to engage the tooth without requiring a spring.
L 100M
4

page_text: I, JAMES ATKINSON, Engineer, of 3 Nassington Road, Hampstead, London N.W.
do hereby declare the nature of my invention for IMPROVEMENTS IN GAS ENGINES,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
I construct my improved Gas Engine in a somewhat similar manner to that
described and illustrated by me in Letters Patent N° 16404 A.D. 1884. and that my
invention may be clearly understood I have fully illustrated its special features in
the accompanying sheets of drawings; in which Fig. 1. Sheet 1. is a plan of the
complete engine; Fig. 2. Sheet 1. is an elevation; Fig. 3. Sheet 1. is an end view ;
Fig. 4. Sheet 1. is a section through the admission and ignition passages; Fig. 5.
Sheet 2. is an elevation of the slide and cover; and Fig. 6. Sheet 2. is a section at
right angles to Fig. 4. Sheet 1.; and in which like figures apply to like parts.
I construct my improved Gas engine with a separate single-acting pump 1. and
a separate single-acting working cylinder 2. The pump 1. may be placed horizon-
tally alongside the working cylinder 2. their respective pistons being driven by
separate crank pins in such a manner that the pump piston follows the working
piston at a small angle, which may be slightly more or less under different circum-
stances, about 30° is a suitable angle under ordinary conditions.
The piston of the pump 1. has as little clearance space when at the inner end of
its travel as is compatible with safety; the pump always pumps an uniform com-
bustible mixture of gas and air, which is drawn in through suitable suction valves 3,
I prefer to use the arrangement of suction valve and governor valve described and
illustrated by me in Letters Patent N° 16404 A.D. 1884. as they have been proved
to work very satisfactorily; there is no necessity for a delivery valve, as the
admission to the working cylinder 2. is controlled by the slide 4. as will be herein-
after explained.
The piston of the working cylinder 2. has only such clearance space when its
piston has completed its exhausting stroke, as is necessary to provide for the
unavoidable deposite that takes place here; just before the completion of this
exhausting stroke, the exhaust valve closes, and the slide 4. opens communication
between the end of the pump into which the combustible mixture which is to
cause the next working stroke is already compressed, and the working cylinder 2,
the compressed combustible mixture passing through the pipe 5, passage 6. through
the outer slide cover, one of the ports 7. in the slide 4. and passage 8. into the
back end of the cylinder 2.; this admission continues during the time the slide
port 7. is passing the openings of the passages 6. and 8. which is also the time in
which the pump piston completes its compressing stroke, and the working piston
performs the first portion of its working stroke, at which time it is cut off by the
continued motion of the slide 4. which closes the communication between the
passage 6. in the outer slide cover and the port 7. in the slide; the port 7. in
the slide however still remains in communication with the passage 8. through
the mouth 9. of the passage 8., which mouth 9. is of an L shape, as shown in Fig. 5.
Sheet 2., immediately after the port 7. cuts off communication with the passage 6.
T

page_text: it opens into the small port 10., formed in the outer cover of the slide, which by
means of a passage 11. is in communication with the igniting tube 12., which
causes the ignition in the following manner :--the pressure from the pump 1, has
charged the end of the working cylinder 2. with the compressed mixture at a
pressure of say 60 lbs. above the atmosphere, at the time the continued motion of
the slide, 4. has carried the port 7. past the mouth of the passage 6., and opened
into the small port 10., thus forming a direct communication between the interior
of the igniting tube 12., and the end of the cylinder 2., the 60 lbs. pressure imme-
diately rushes into the tube 12., which is kept red hot where bent upwards at 13.,
and is instantly ignited, sending a strong rush of flame through the ports 7. and 9.
and passage 8. thus firing the working charge and giving a working pressure
during the remainder of the working stroke, at the end of this working stroke the
exhaust valve 14. is opened by the exhaust eccentric and rod 15., allowing the
exhaust to pass out on the return stroke; the pump 1. is meanwhile drawing in
and compressing another charge, ready to repeat the cycle of operations necessary
to cause another working stroke, which is repeated at every revolution of the
crank shaft.
It will be understood that as the slide 4. revolves after the ignition takes place,
the port 7. cuts off communication with the small port 10., shutting pressure inside
the igniting tube 12., which would, if not released, prevent ignition taking place at
the next revolution; it is therefore necessary to ventilate it so as to allow the
pressure inside the tube to fall to about atmospheric pressure, which is done by
means of the passages 16. and 17., which are placed in communication with each
other by means of one of the ports 7.; in the position shown in Fig. 5 this com-
munication is just cut off at the time one of the ports 7. is about fully open to
passages 6. and 8., that is to say, a short time only before ignition takes place.
It will be seen that the slide 4. consists of a thin disc, rotating in the direction
shown by the arrow in Fig. 5. Sheet 2., rotating on the pin 18. It is revolved by
means of the eccentric and rod 19., which operates the pawl 20., there are any
convenient number of ratchet teeth in the periphery of the slide 4., the number of
the ports 7. corresponding with the number of the ratchet teeth. In the slide 4..
shown there are 12. of each of these, and the slide 4. makes one revolution for
twelve revolutions of the engine, it consequently has a slow motion, and works
with little friction, also about two-thirds of its area is continually exposed to the.
atmosphere, which keeps it comparatively cool, and the rotary motion in one
direction only, makes it much less liable to abrasion. The outer slide cover is
pressed against the slide, and the slide against the inner face by means of a
spring 21., acting through the lever 22. The spring 21. has a definite strength,
and the nut 23. is screwed home, so that it is not within the power of the attendant
to put an excessive pressure upon the slide. The pawl 20. falls upon a piece of
leather or other suitable substance 24. and not upon the bottom of the tooth, thus
preventing noise, no spring is required to force the pawl down, as this is done
partly by its own weight, and partly by its momentum on being reversed; the
stroke of the eccentric 19. is just sufficient to move the pawl very little more than
the length of one tooth, so that no shock or noise is caused by the pawl coming in
contact with the tooth; this length of stroke of the pawl can be very accurately
adjusted by lengthening or shortening the pawl, and lengthening or shortening the
eccentric rod to suit, so that the pawl lever works at varying angles with the
eccentric rod, and its stroke in relation to the eccentric can be very accurately
regulated by this means.
The chimney 25. may be of cast iron lined with asbestos, or of terra cotta, or
other suitable refractory material; the heat for making the igniting tube red hot
may be obtained from a bunsen burner 26.
I wish it to be understood that the arrangement of slide is developed from
igniting tubes and slides which I have described and illustrated in several previous
Letters Patent, the novelty in this invention being chiefly in the general com-
bination and arrangement of parts, and the method of driving; the circular slide

page_text: described and illustrated by me in Letters Patent 3039 A.D. 1884 is very similar,
but it was rotated continuously by gearing, and the present one is worked direct
by means of an eccentric, the result being that combined with the arrangement
described above it is operated much more quietly, requires less power to drive,
works cooler and is more durable:
The pump 1 and working cylinder 2 may be arranged at an angle with each
other so that their respective pistons may be driven by one crank pin, the centre
lines of the pump 1 and working cylinder 2 being in different vertical planes, so
that their connecting rods may clear each other, and have the crank pin brasses
alongside each other on the same pin, also two or more engines may be connected
so as to form a combined engine.
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. The arrangement and construction of Gas Engines operating substantially as
described and illustrated in the accompanying drawings.
2. The rotary slide moved directly by ratchet teeth and arranged and constructed
as described and illustrated in the accompanying drawings.
3. In Compression Gas Engines the use of a thin, flat, rotary slide, driven
directly and intermittently by means of ratchet teeth, and having only a number
of ports cut through it, so arranged that each port in succession allows the com-
pressed charge to pass into the working cylinder through it, and also transmits the
ignition through the same port without requiring any small grooves or passages in
the slide.
Dated this 24th day of December 1885,
Witnessed by
GEORGE THOMAS HARRAP,
35, Upper Tollington Park, London.
JAMES ATKINSON.