IMPROVEMENTS IN HOT-AIR ENGINES
Year: 1883

page_text: LETTERS PATENT to Henry Harris Lake, of the firm of Haseltine, Lake
and C° Patent Agents, Southampton Buildings London for an Invention of
"IMPROVEMENTS IN HOT-AIR ENGINES" Communicated to him from abroad
by Josef Schreiber and Mathias Fellner both of Vienna in the Empire of
Austrin
PROVISIONAL SPECIFICATION left by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 13th January 1883.
HENRY HARRIS LAKE, of the firm of Haseltine Lake and Co, Patent Agents
Southampton Buildings London "IMPROVEMENTS IN HOT-AIR ENGINES"
[A communication to him from abroad by Josef Schreiber and Mathias Fellner
both of Vienna in the Empire of Austria]
This Invention relates to improvements in hot-air engines or motors, which are
specially designed for driving small machines such as sewing machines.
The said Invention consists partly in providing the cylinder of an air engine or
motor, at a point between the extreme positions occupied by the piston, with
means whereby, at certain moments during the ascent of the said piston, air will be
admitted into the cylinder and allowed to pass out during its descent; and the
said Invention comprises means for adjusting and fixing the lead of the displacer or
plunger with regard to the piston.
In carrying the said Invention into practice, I provide a cylinder having a heat-
chamber bolted thereto, and a displacer or plunger and a piston working therein.
The said piston is formed with a long bored boss for guiding the rod of the
displacer, which slides through it; a tank for containing cooling water surrounds
the cylinder. Under the heat chamber the firing is placed. Two bearing brackets
are bolted on to the water tank, and these carry the fly-wheel shaft. This shaft is
cranked for receiving the connecting rod which is connected with the piston by
the bolt on which it moves. In order to give the displacer the required lead with
regard to the piston a disc is fixed on the crank shaft having a pin carrying a
roller screwed therein which roller moves in a horizontal roller-guide or slot to
which the displacer rod is fixed, whereby the said displacer or plunger is moved

page_text: vertically up and down. The said roller pin is screwed into the said disc at such a
distance from its centre that the displacer or plunger has a somewhat longer stroke
than the piston. The roller pin can easily be adjusted after the lead of the displacer
or plunger with regard to the piston.
In order to obviate the injurious effect accruing in most hot air engines, caused
by the vacuum produced in the cylinder during the ascent of the piston, and the
compression produced during the descent of the said piston, I form in the side of
the cylinder several holes or ports through which air can pass in or out. These
holes or ports, the number of which is varied according to desire and requirement,
are arranged in such a manner that the ingress and egress of the air never can begin
at the lowest position of the piston, but only at other fixed points.
The reasons why the egress and ingress of the air have to be regulated in this
manner are that the piston, after completing say one eighth part of its up-stroke,
begins to produce an injurious vacuum behind it; according to the present Invention
nir is allowed to enter the cylinder through one of the ports in a small quantity.
At about the middle of the stroke another port is opened and an increased quantity
of air is admitted at about three fourths of the up-stroke of the piston; the supply
of air is again diminished and in such a manner that while the lower openings or
ports are closed an upper one is opened, and then later, when the piston has
completed, say about seven eighths of its up-stroke, again completely closed. It is
necessary. that the said port should be closed at this point, because the vacuum
which is created beneath the piston during the last part of its stroke is used to
assist in bringing the crank over the dead centre. When the piston has completed
say one quarter of its return stroke the injurious effect caused by compression is
obviated by the same means in that the air is allowed to escape through the said
ports.
When the piston has performed about seven eighths of its down stroke all the
openings or ports are closed and the air under the piston which has been cooled is
forced back into the heat-chamber in order to be again expanded by the heat.
I would here observe that any arrangement that would bring the outer atmosphere
into communication with the heated air inside the cylinder is objectionable if it
begins while the piston is in its lowest position, and that it not only does not
assist in moving the piston (as the formation of a vacuum has first an injurious
effect at about one eighth of the stroke of the piston) but the admission of cold air
at the beginning of the stroke of the piston would have an injurious effect.
The slide valve is worked by a common excentric with a rod; the said excentric
is fixed on the fly-wheel shaft.
In order to be able to regulate the air inlet and outlet to the greatest nicety, an
air-chamber is provided in which are two or more air-flaps or valves arranged in
such a manner that one of them opens inward when the piston ascends, and the
other one opens outwards when it descends, and thus air is let in or let out. In
order to regulate the action of these flap-valves and be able to determine the
amount of air passing, adjustable springs can be applied.
Instead of a flat slide-valve, a slide having the form of a segment of a circle can
be used.
Instead of the horizontal slot for moving the displacer or plunger, the plunger rod
may be provided with a vertical slot which surrounds the crank-shaft which acts as
a guide, and a roller which runs in a circular groove in the face of a disc arranged
excentrically on the said shaft.
In a double cylinder engine the cylinders may be arranged with a common air
space between them in which the slide valves work; in this case one set of flap-
valves only is necessary.

page_text: holes or ports, the number of which may be varied according to desire and require-
ment, are arranged in such a manner that the ingress and egress of the air can
never begin when the piston is in the lowest position, but only at other fixed
points.
The reasons why the egress and ingress of the air have to be regulated in this
manner are that the piston, after completing say one eighth part of its up-stroke,
begins to produce an injurious vacuum behind it, according to the present invention
air is allowed to enter the cylinder, at about this point, in a small quantity through
the port a¹; at about the middle of the stroke, the port a is opened and an increased
quantity of air is admitted; at about three-fourths of the up-stroke of the piston,
the supply of air is again diminished, for the reason that the lower ports a, a¹ are
closed and a smaller port a³ is opened, and this latter, when the piston has com-
pleted say about seven eighths of its up-stroke, is again completely closed. It is
essential that the port a should be closed at this point, because the vacuum which
is created beneath the piston during this last part of its stroke is utilized to assist
in bringing the crank over the dead centre. When the piston has completed say
one quarter of its return stroke, the injurious effect caused by compression is
obviated by the same means, in that the air is allowed to escape through the said
ports. When the piston has performed about seven eighths of its down stroke, all
the openings or ports are closed, and the air under the piston, which has cooled, is
forced back into the heat-chamber, in order to be again expanded by the heat. I
would observe that any arrangement which would bring the outer atmosphere into
communication with the heated air inside the cylinder is objectionable, if it begins
when the piston is in its lowest position, and that the admission of air not only
does not assist in moving the piston, (as the formation of a vacuum does not begin
to have an injurious effect till about one eighth of the stroke of the piston is
performed) but, at the beginning of the stroke of the piston, it would have an
injurious effect.
The slide-valve P is moved in the ordinary manner by an excentric M provided
with a rod N, the said excentric being fixed on the fly-wheel shaft H.
In order to be able to regulate the admission and discharge of the air to the
greatest nicety, an air-chamber E is provided in which are two or more air-flaps or
valves e, e, arranged in such a manner that one of them opens inwardly when the
piston ascends, and the other one opens outwardly when it descends. In order to
regulate the action of these flap-valves c, c, and be able to determine the amount
of air passing through them, adjustable springs can be applied.
Instead of a flat slide-valve P, as shown in Figure 1, a slide having the form of
a segment of a circle can be used, as shown in Figure 3; also instead of the
horizontal slotted link L (shown in Figures 1 and 2) for moving the displacer or
plunger C, the plunger rod may be provided with a vertical slotted link X which
surrounds the crank-shaft the latter acting as a guide, as shown in Figures 9
and 10; in this case the disc S is arranged excentrically upon the crank-shaft and
is provided upon the face with a groove S' in which the roller T upon the lower
end of the said link runs.
In a double cylinder engine, the cylinders may be arranged with one air-space E
in which the slide-valves work, as shown in Figure 9, when one set of flap-valves
only is necessary; also the slotted link, as shown in Figure 10, is used for one of
the plunger rods.
In order to be enabled to reverse the engine, the disc to which the valve-rod is
connected, and which is fixed on the crank-shaft, is arranged to be shifted by
means of a slot and a screw, as shown in Figures 11 and 12, in which U indicates
the said disc, which is placed on the crank-shaft H and counected at V with the
valve-rod. In this disc U, n slot W is formed through which passes a bolt Y
which is screwed into the crank H'. It is obvious that, when the bolt Y is
slackened, the disc U can be turned so far round that the connection with the
valve-rod V can be shifted to the position V', shown in dotted lines, and thus
the motion of the machine can be reversed.

page_text: According to a modification of the arrangement for regulating the size of the
opening connecting the slide-valve chest with the atmosphere and shown in
Figures 13 and 14, I provide the opening Z with a device which can be regulated
in order to obtain a quicker or a slower motion of the machine. In the case of
small machines, a screw Z' may be used as shown in Figure 14. Or instead of the
screw Z', a slide Z which is shifted in guides by means of a screw, as shown in
Figure 15, may be used, or a cock or any similar well known device which can be
closed or opened more or less either by hand or automatically by means of a ball
governor or some similar speed regulator.
Having thus fully described the said invention as communicated to me by my
foreign Correspondents and the manner of performing the same I wish it understood
that I Claim:―
First. The construction of a cylinder of a hot-air engine with holes or ports.
arranged between the extreme positions occupied by the piston, whereby the
admission and discharge of the air can be regulated, substantially as described.
Second. The slide-valve P, in combination with the cylinder having the holes
or ports arranged as described for the purpose specified.
Third. A hot-air engine or motor in which the slide-valve chest communicates
with the atmosphere through an opening, the size of which can be varied for the
purpose of regulating the speed of the engine, as above set forth.
Fourth. The combination of the slide-valve chest having an opening Z, with
meaus substantially as described with reference to Figures 13, 14 and 15 of the
drawings for regulating the size of the said opening.
Fifth. The combination, with the slide-valve, of an air-chamber provided with
adjustable flap-valves for regulating the admission and discharge of the air,
substantially as, and for the purpose, set forth.
Sixth. The mechanism for operating the displacer, which mechanism consists of
the disc J and the roller attached thereto arranged to move in the horizontal
slot in the link L, substantially as described with reference to Figures 1 and 2 of
the drawings.
Seventh. The double cylinder engine constructed and arranged substantially as
shown in Figures 9 and 10 of the drawings.
Eighth. The mechanism, as described with reference to Figures 9 and 10 of the
drawings, for operating the displacer, which mechanism consists of a disc S mounted
excentrically upon the crank-shaft and having a groove S' engaging with the
roller Tattached to the slotted link X.
..
Ninth. The slide valve for regulating the admission and discharge of air, the
said valve being made in the form of a segment of a circle, substantially as
described with reference to Figure 3 of the drawings, for the purpose specified.
Tenth. The adjustable disc U having the slot W and the set-screw Y for
reversing the motion of the engine, substantially as described.
In witness whereof I the said Henry Harris Lake have hereunto set my hand
and seal this tenth day of July in the year of Our Lord one thousand
eight hundred and eighty three.