A New or Improved Rotary Engine.
Year: 1898

page_text: Date of Application, 19th Mar., 1898
Complete Specification Left, 19th Dec., 1898-Accepted, 4th Feb., 1899
A New or Improved Rotary Engine.
1, CHARLES SINCLAIR DRUMMOND, of St. George's Club, Hanover Square, in
the County of London, Gentleman, do hereby declare the nature of this invention
to be as follows:-
My invention relates to a new or improved rotary engine by means of which
the advantage of long stroke, as it is termed when applied to a reciprocating
engine, is obtained. In my invention I employ a tube bent or coiled in such
manner that it is closed upon itself so as to form a long continuous passage.
This tube is designed to fulfil the functions of an engine cylinder and it is
mounted upon a shaft through which the steam, compressed air or the like may
be fed and exhausted. Within the said tube and capable of moving freely
therein is a heavy weight designed to fulfil the functions of a piston. The tube
is further provided with slides or valves capable of being opened and closed and
which when closed fulfil the functions of the cylinder ends or covers.
is further provided with inlet and outlet tubes or ports.
versa.
The tube
The action is as follows: Let us assume that steam is admitted between one
end of the weight and a closed valve or slide in the tube. The expansion will
tend to propel the weight through the tube; but inasmuch as the said weight is
very heavy as compared with the tube, the steam pressure acting upon the closed
valve will force round the coiled tube witli its shaft, whilst the weight will
remain in a fixed or in a nearly fixed position. Let us assume now that the
coiled pipe has two slides, two inlet pipes and two outlet pipes; and that whilst
one slide is open the other is closed and vice versa; also that when one inlet
pipe is admitting steam the corresponding outlet pipe is exhausting and vice
Steam being now admitted through one inlet pipe between a closed
slide and the weight and the weight remaining steady the tube will be forced
round with its shaft whilst the open slide will allow the tube to pass over the
weight. When the latter slide has now passed over the weight it is closed
steam is admitted between it and the weight and further expansion continues
the rotary movement of the tube. It will thus be seen that each slide is open
as it approaches the weight and closed on receding from it: and that steam
is admitted between the said slide immediately after it is closed, and is exhausted
on the other side of the said slide. It will further be understood that the
purpose of
inlet pipes and outlet pipes or ports are provided with valves for the
establishing or shutting off communication with the steam supply or with the
atmosphere as the case may be.
In one form of my invention I propose to coil the tubes through two complete
revolutions so as to resemble two rings meeting at one point and having the
passage at the point common to both rings. Seen in side elevation the tube will
now resemble the letter V it being assumed that the point at which the two
rings meet, so to speak, is vertically below the shaft. In this form, if we
assume for a moment that instead of the weight occupying a fixed position and

page_text: the tube moving the tube occupies a fixed position and the weight moves, then,
starting from the point where the two rings meet, the weight would traverse
one ring and then continue round the other ring, thus traversing the whole
length of the tube, and at the same time making two complete revolutions round
the shaft before it again started over the same course. In this form there is
space for a much greater expansion of the steam than if the tube were coiled
into a single ring; and I obtain by this means the effect of a much longer
stroke, so to speak.
In another form of my invention I propose to coil the tube into a helix of
several turns, the two ends being connected together. It will be seen that in
this form owing to the great number of turns a still longer stroke, so to speak,
is obtained, it being borne in mind of course that the same number of slides is
employed for it is obvious that increase of stroke would not follow if the
number of slides were proportionately increased. In this helical form of my
invention it will be seen that in order that the tube may be continuous, or
closed upon itself, the curve must vary and that therefore if the weight is a
long one (and in practice a considerable length is desirable in order that the
weight may be sufficiently heavy), it must be flexible. To make it so I build
it up of a number of short pieces articulated together in any convenient manner
so that it may take a curve very much as a railway train composed of several
short lengths (the carriages) takes curves and changes of gradient.
It is to be understood that the valves whether those which fulfil the functions
of cylinders bottoms or covers or those controlling the passage of the steam may
be actuated in any convenient manner known in the art.
The
My invention also embraces what I may for the purposes of this specification
term a crossing switch, that is to say a device enabling (here I again assume
for convenience of description that it is the weight which is traversing the tube
and not the tube which is rotating whilst the weight is stationary or nearly 30)
the weight to pass from one ring or convolution to its neighbouring one.
said crossing switch is placed at the bottom of the V or the part where the two
rings join and it consists of a tube, chamber or the like capable of limited
angular movement after the manner of a turntable and having attached to it
slides preferably of arc shape which serve to open and close the tubular passage
for the purpose herein before mentioned with reference to the other form of slide.
This part of my engine may be boxed in in a steam tight manner and may be
provided with recesses into which the arc shaped slides may nest.
Dated this 10th dow of Vanak 19ne
I, CHARLES SINCLAIR DRUMMOND, of St. George's Club, Hanover Square, ia
the County of London, Gentleman, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement; -
My invention relates to a new or improved rotary engine by means of which
the advantage of long stroke, as it is termed when applied to a reciprocating
engine, is obtained. In my invention I employ a tube bent or coiled in such a

page_text: manner that it is closed upon itself so as to form a long continuous passage.
This tube is designed to fulfil the functions of an engine cylinder and it is
mounted upon a shaft through which the steam, compressed air or the like may
be fed or exhausted. Within the said tube and capable of moving freely
therein is a heavy weight designed to fulfil the functions of a piston. The tube
is further provided with slides or valves capable of being opened and closed and
which when closed fulfil the functions of the cylinder ends or covers. The tube
is further provided with inlet and outlet tubes or ports.
versa.
now that the
The action is as follows: Let us assume that steam is admitted between one
end of the weight and a closed valve or slide in the tube. The expansion will
tend to propel the weight through the tube: but inasmuch as the said weight is
very heavy as compared with the tube, the steam pressure acting upon the closed
valve will force round the coiled tube with its shaft, whilst the weight will
remain in a fixed or in a nearly fixed position. Let us assume
coiled pipe has two slides, two inlet pipes and two outlet pipes and that whilst
one slide is open the other is closed and vice versa; also that when one inlet
pipe is admitting steam the corresponding outlet pipe is exhausting and vice
Steam being now admitted through one inlet pipe between a closed
slide and the weight and the weight remaining steady the tube will be forced
round with its shaft whilst the open slide will allow the tube to pass over the
weight. When the latter slide has now passed over the weight it is closed
steam is admitted between it and the weight and further expansion continues
the rotary movement of the tube. It will thus be seen that each slide is open
as it approaches the weight and closed on receding from it: and that steam
is admitted between the said slide immediately after it is closed, and is exhausted
on the other side of the said slide. It will further be understood that the
inlet pipes and outlet pipes or ports are provided with valves for the purpose of
establishing or shutting off communication with the steam supply or with the
atmosphere as the case may be.
In one form of my invention I coil the tubes through two complete
revolutions so as to resemble two rings meeting at one point and having the
passage at the said point common to both rings. Seen in side elevation the tube will
now resemble the letter ✓ it being assumed that the point at which the two
rings meet, so to speak is vertically below the shaft. In this form, if we
assume for a moment that instead of the weight occupying a fixed position and
the tube moving the tube occupies a fixed position and the weight moves, then,
starting from the point where the two rings meet, the weight would traverse
one ring and then continue round the other ring, thus traversing the whole
length of the tube, and at the same time making two complete revolutions round
the shaft before it again started over the same course. In this form there is
space for a much greater expansion of the steam than if the tube were coiled
into a single ring and I obtain by this means the effect of a much longer
stroke, so to speak.
The
My invention also embraces what I may for the purposes of this specification
term a crossing switch, that is to say a device enabling (here I again assume
for convenience of description that it is the weight which is traversing the tube
and not the tube which is rotating whilst the weight is stationary or nearly so)
the weight to pass from one ring or convolution to its neighbouring one.
said crossing switch is placed at the bottom of the V or the part where the two
rings join and it consists of a tube chamber, or the like capable of limited
angular movement after the manner of a turntable and having attached to it
slides preferably of are shape which serves to open and close the tubular passage
for the purpose hereinbefore mentioned with reference to the other form of slide.
This part of my engine may be boxed in a steam tight manner and may be
provided with recesses into which the arc shaped slides may nest.
This form of my invention is illustrated in Figures 1, 2 and 3.

page_text: Figure 1 is a section at right angles to the snart.
Figure 2 is a section parallel to the shaft.
Figure 3 is a detail view of the crossing switch.
In Figures 1 and 2 the tube 1 is shown in side elevation being in this case
built up of segments bolted together and strengthened by flanges 2. The tube
is supported by eight radial arms 3, springing from two hubs 4 fixed on the main
shaft J.
At the point where the two limbs of the tube cross one another is the crossing
switch 6, shown in detail in Figure 3. Where the two limbs are furthest apart
they are braced together by a connecting piece 3º.
The shaft 5 bears in two blocks 7, and is hollow through nearly the whole
of its length, being provided with two steam passages 8 and 9; these passages
are deflected at the centre and connected by steam pipes 10 and 11, to the
crossing switch 6. The outside ends of the steam passages 9 and 10 are connected
respectively to the steam inlet and to the exhaust by means of a valve 12 and a
sliding joint 13, so arranged as to admit and exhaust the steam while the shaft
is turning.
The steam is admitted through the passage 9 and passes by the pipe 11 into the
crossing switch 6, the detailed action of which is hereinafter explained, it then
passes up by the pipe 10 and out into the exhaust through the passage 8.
In Figure 1 a part of one limb of the tube is removed to show the weight 14 in
the position it occupies when the engine is running.
In Figure 3 the crossing switch 15 is shown in section. 23 is a sliding valve
for closing the one limb of the tube. The passage 25 connects the two limbs of
the tube alternately. In the figure the weight 14 is shown close up to the switch.
Steam is now entering by the port 16 and forcing the weight away from the
switch and the exhaust steam is passing out through the exhaust port 20.
The weight travels, relatively to the tube, round the limb 17 of the tube and
passes through the crossing switch. It then travels round the other limb 18
until its rear end clears the port 19. At this point live steam is admitted through
the pipe 21 and into the space 22 forcing the switch over, by means of the
piston 24. At the same time the valve 12 shown in Figure 2, cuts off the
steam.
When the weight has passed through the crossing switch the valve 12 admits
steam to the port 16 and forces the sliding valve 23 over so that the equivalent of
a cover plate is placed behind the weight at the Name time that steam
passes through 26 and forces the weight, relatively forward.
In another form of my invention propose to coil the tube into a helix of
several turns the two ends being connected together.
In Figure 4 I represent such in a purely diagrammatic form and it being
evident that such form is here represented for purposes of description merely
and not for purposes of construction. It will be seen that in this form owing
to the greater number of turns a still longer stroke, so to speak, is obtained, it
being borne in mind of course that the same number of slides is employed: for
it is obvious that increase of stroke would not follow if the number of slides
were proportionately increased. In this helical form of my invention it will
be seen that in order that the tube may be continuous or closed upon itself, the
curve must vary and that therefore if the weight is a long one (and in practice
a considerable length is desirable in order that the weight may be sufficiently
heavy) it must be flexible. To make it so I build it up of a number of short
pieces articulated together in any convenient manner, one form of which is shown
in Figure 5 so that it may take a curve very much as a railway train composed of
several short lengths (the carriages) takes curves or changes of gradient. In
this figure, which is a diagrammatic representation of an articulated weight, 27
27 are the individual weights articulated by joints 28, 28. . the whole
thus capable of moving smoothly in the tube and passing round curves.

page_text: 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. In a rotary engine of the type specified the means for obtaining "long
stroke substantially as set forth.
"
"
2. In an engine of the type specified and designed for obtaining "long stroke
the employment of a crossing switch substantially as and for the purpose set
forth.
"
3. In an engine of the type specified and designed for obtaining "long stroke
the employment of an articulated weight substantially as and for the purpose
set forth.
4. The arrangement and combination of parts substantially as set forth with
reference to Figures 1 2 and 3
Dated this 19th day of December 1898.
For the Applicant,
J. G. LORRAIN, M.I.E.E., &c.,
Norfolk House, Norfolk Street, Strand, W.C.,
Chartered Patent Agent.