IMPROVEMENTS IN AIR AND GAS ENGINES OR MOTORS
Year: 1875

page_text: LETTERS PATENT to John Farmerley Dickson, of Leicester, in the
County of Leicester, for the Invention of "IMPROVEMENTS IN AIR AND
GAS ENGINES OR MOTORS."
Sealed the 18th June 1875, and dated the 1st March 1875.
PROVISIONAL SPECIFICATION left by the said John Farmerley Dickson
at the Office of the Commissioners of Patents, with his Petition,
on the 1st March 1875.
I, JOHN FARMERLEY DICKSON, of Leicester, in the County of Leicester,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN AIR AND GAS ENGINES OR MOTORS," to be as follows:-
My Invention has relation to that class of gas engines in which power
is communicated from a piston to a wheel on the main shaft of the
engine by means of a toothed rack on the face of the rod of said piston,
this wheel being free to turn in one direction but prevented from turning
in the other direction by a ratchet wheel, by means of which motion is
communicated to the main shaft. Patent, No. 16557, belongs to this
class of engine in which the power is exerted on the ascent of the piston
after explosion. Patents, Nos. 434% and 2245", also belong to this

page_text: class, differing only from the first mentioned by the driving power being
exerted on the main shaft during the down stroke of the engine piston
by atmospheric pressure, in the first case disregarding the pressure of
the atmosphere, in the other the explosive and expansive power of the
gas.
My Invention differs from both, and consists in utilizing both the out-
ward and inward stroke, that is to say, I utilize both the explosive power
of the gas and the atmospheric pressure resulting from the partial
vacuum caused by the explosion of the gas. I do this by making two
racks on the piston-rod, one gearing into a wheel on the main shaft and
exerting power during the descent of the piston by atmospheric pressure,
the other rack gearing into a wheel similar in construction but double
the size in diameter, by which power is exerted on the main shaft
through the intermediation of other wheels, so that while the speed of
the engine continues uniform, the piston, during its up stroke, travels at
twice the speed it does during its down stroke. By this arrangement
thepawls used in Otto and Langen's Invention to raise the piston at the
termina ion of its down stroke are dispensed with, and the engine in
every respect simplified.
1
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Farmerley Dickson in the Great Seal Patent
Office on the 1st September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
FARMERLEY DICKSON, of Leicester, in the County of Leicester, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of March, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Farmerley Dickson, Her special
licence that I, the said John Farmerley Dickson, my executors, admi-
nistrators, and assigns, or such others as I, the said John Farmerley
Dickson, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might

page_text: make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an In-
vention for "IMPROVEMENTS IN AIR AND GAS ENGINES OR MOTORS," upon
the condition (amongst others) that I, the said John Farmerley
Dickson, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said John Farmerley Dickson, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, reference being had to the
Drawings hereunto annexed, that is to say :-
My Invention has relation to that class of gas engines in which power
is communicated from a piston to a wheel on the main shaft of the
engine by means of a toothed rack on the face of the rod of said piston,
this wheel being free to turn in one direction, but prevented from
turning in the other direction by a ratchet wheel, by means of which
motion is communicated to the main shaft. Patent, No. 16555, belongs
to this class of engine in which the power is exerted on the ascent of
the piston after explosion. Patents, Nos. 434 and 22450, also belong
to this class, differing only from the first mentioned by the driving power
being excrted on the main shaft during the down stroke of the engine
piston by atmospheric pressure. In the first case disregarding the
pressure of the atmosphere in the other the explosive and expansive
power of the gas.
My Invention differs from both, and consists in utilizing both the
outward and inward stroke, that is to say, I utilize both the explosive
power of the gas and the atmospheric pressure resulting from the partial
vacuum caused by the explosion of the gas. I do this by making two
racks on the piston rod, one gearing into a wheel on the main shaft and
exerting power during the descent of the piston by atmospheric pressure,
the other rack gearing into a wheel similar in construction but of
larger size in diameter, by which power is exerted on the main shaft
through the intermediation of other wheels, so that while the speed of

page_text: the engine continues uniform, the piston, during its up stroke, travels
at a greater speed than it does during its down stroke. By this arrange-
ment the pauls used in Otto and Langen's Invention to raise the
piston at the termination of its down stroke are dispensed with, and the
engine in every respect simplified.
༔ ་་
My Invention is clearly represented in the accompanying Drawings,
in which Figure 1 is an elevation of air engine cylinder A on the flange
B, of which are standards or plummer blocks C, C, for carrying two
transverse shafts D, E, as more particularly shown in Figure 2. The
shaft D has a spur wheel F in gear with the teeth on one side of the
piston rod G, and which is forced up by the explosive action of the gas
employed against the under side of the piston H. The spur wheel F in
the up stroke of the piston effects the rotation of the shaft D by the
engagement of the paul I with the teeth of the ratchet wheel J as
shown, so that the shaft D turns therewith and causes the wheel K to
turn also, which wheel, by gearing into the pinion L, communicates a
rotating motion in the reverse direction of the wheel M on the shaft E.
The shaft E carries a wheel N, whose teeth gear into the rack on the
other face of the piston rod G, and gives power while being forced down
by atmospheric pressure on the upper surface of the piston H, the top
end of the cylinder being open for the purpose; this causes the shaft E
to be pulled round at a speed proportionate to the descent of the piston.
The spur wheels are of different diameter as shown, and as the piston
ascends under the pressure or force of the explosive gases within the
cylinder in the manner well known, at a greater speed than it descends
under atmospheric pressure, an equalization, or nearly so, of the band
wheel P from which machinery may be driven, is effected, the momentum
of the fly wheel Q also assisting to produce uniformity of speed of, the
whole of the machinery. The spur wheel N has also a ratchet wheel R
and paul S arrangement for maintaining the motion of the machinery
during the down travel of the piston, each wheel F and N running idle
alternately on the change of travel of the piston rod by the pauls slipping
over the teeth of the ratchets.
Figure 3 represents a lift wheel T on the shaft D, which wheel has on
its rim three equidistant projections, one of which, when the piston has
arrived at the end of its down stroke, comes under a lip U on the piston
rod as in Figure 2, and causes the piston to rise a short distance and so
start it on its up stroke. A vacuum being thus formed beneath the

page_text: piston, facilitates the entry of the gas and the flame to ignite it, the
expansion of the gas confined within the cylinder then continuing the
up stroke in the usual manner.
The valves for the supply and lighting of gas and air to the cylinder,
and for the exit of the waste or exploded gas, are made in the usual and
well known manner.
I have referred to a wheel with projections as being employed for the
purpose of starting the piston upwards, but a cam on the shaft acting
upon a rock lever or other appliances may be fitted as desired. The lip
piece is preferably adjustable.
Having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,-
The employment of a double rack or two separate racks upon the
piston rod of an air and gas engine or motor, and two wheels to gear
therein, and transmit power in alternate order for moving mechanism as
described and substantially as shown in the accompanying Drawings.
Secondly. I claim the combination of appliances fitted on or to an
air and gas engine or motor, as and for the purposes set forth.
Thirdly. I claim the direct starting wheel T on or from the shaft D,
and the lip piece U on a piston rod G, as and for the purposes set forth
when employed with air and gas engines or motors.
Fourthly. I claim constructing air and gas engines as described, in
such a manner that while the out stroke of the piston is quicker than
the return stroke the speed of the main shaft still continues uniform as
set forth.
In witness whereof, I, the said John Farmerley Dickson, have here.
unto set my hand and seal, this Thirty-first day of August, One
thanmond night hundred and seventy-five
0 Witness,
H. GARDNER,
166, Fleet Street,
London.
JNº. F. DICKSON. (L.S.)