AN IMPROVED ROTARY STEAM-ENGINE
Year: 1882

page_text: LETTERS PATENT to John Pinchbeck of No 3 Westminster Chambers Victoria
Street in the County of Middlesex, Civil Engineer for an invention of AN
IMPROVED ROTARY STEAM-ENGINE
PROVISIONAL SPECIFICATION left by the said John Pinchbeck at the Office
of the Commissioners of Patents on the 19th July 1882.
JOHN PINCHBECK of N° 3 Westminster Chambers Victoria Street in the County
of Middlesex Civil Engineer AN IMPROVED ROTARY STEAM ENGINE
The object of this invention is to obtain a Steam tight abutment Valve of such a
form as to cause a considerable amount of surface always to be in contact with the
Piston at any portion of its stroke and to employ the various angles which the
Eccentric Piston makes as it revolves as a means for opening or shutting the
admission ports through which steam enters the Cylinder and without the use of
a seperate Valve, the abutment Valve being also the steam admission Valve
It would be extreemly difficult to convey in words an accurate idea of the
invention I have thought it better to deposit with this Specification a drawing
which clearly explains my intention Figures 1, 2, 3, 4 relate to a Rotary Steam
Engine to turn in one direction alone Figre 5, 6, & 7 to a reversing Engine A is
an ordinary Cylinder. B centre Shaft C Eccentric Piston D Slide box E the
slide which is forced down onto the Piston by the pressure of the steam as it enters
through the passages F & F' acting against the Valve box cover G.
rocking on the lower end of the slide E and with a broad face fitting on the
His a valve
piston C at any position In this rocking valve is a passage which openes or shuts
according to the angle it assumes. In Fig 1 the passage is just opening to admit
steam-Fig 2 it is full open Fig 3 closed at one half revolution of the Piston, the
steam expands till it reaches the point I when it escapes into the atmosphere till it
reaches again the point shewn at Fig 1. Fig 4 is a plan of slide for single running
Engines showing the passage K for steam in centre
In making a reversing Engine I divide the slide E into two compartments Fig 7
into either of which steam is admitted. I also make two passages in the Rocking
Valve H on different planes Fig 5 The Exhaust Ports 1 I' are fitted with slides
worked by levers The slide E Fig 5 is cast with a cover leaving a space L into
which steam is admitted to keep it down to the Piston, but instead of steam I may
employ outside eccentrics or springs for the same purpose

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Pinchbeck in the Great Seal Patent Office on the 19th January
1883.
JOHN PINCHBECK, of 3 Westminster Chambers, Victoria Street, in the County
of Middlesex, Civil Engineer, "AN IMPROVED ROTARY STEAM ENGINE
"
5
This Invention relates to an improved rotary steam engine.
The object of the Invention is to obtain a Steam tight abutment valve of such a
shape as to cause a considerable amount of surface always to be in contact with
the piston at any portion of its revolution, and to employ the various angles which
the eccentric piston makes as it revolves as a means for opening or shutting the 1
admission ports through which steam enters into the cylinder; and without the use
of a separate valve, the abutment valve being also the steam admission valve.
In the accompanying Sheet of Drawing:-
Figure 1 is a transverse section through a rotary engine embodying my
Invention.
Figures 2 and 3 are similar views but illustrate altered positions of pistons and
valves
Figure is a plan of the slide
Figure 5 Being a transverse section through an engine arranged to run in either
direction
Figure 6 is a plan of a rocking valve adapted for working same, and
Figure 7 a top view of the slide.
Figure 8 Being a longitudinal section through a pair of engines shewing position
of slides and rocking lever for retaining same in position.
Similar letters of reference indicate similar parts in each of the Figures
respectively.
Figures 1, 2, 3 and 4 relate to a rotary steam engine running in one direction
alone and Figures 5, 6, 7 and 8, to a reversing engine.
I will first describe my improved rotary engine as shown Figs: 1, 2, 3 and 4.
A is an ordinary cylinder; B, the centre shaft; C the eccentric or piston; D the
slide box; E the slide, which is forced down onto the piston by the pressure of
stean as it enters through the passages F and F' acting against the valve box
cover G; H is a valve rocking on the lower end of the slide E, and with a broad
face fitting on the piston C at any position. In this rocking valve is a passage
In Figure 1 the passage
which opens or shuts according to the angle it assumes.
is just opening to admit steam. In Fig 2 the port is full open. In Fig: 3 the
port is closed at one half revolution of the piston and the steam expands till it
reaches the point I, when it escapes into the atmosphere, and continues to do so
At Fig 4 will be seen
until the port again reaches the position shown at Fig: 1.
the passage K in the centre of the slide for single running engines.
I will now proceed to describe my improved rotary engine with reversing
motion, as shown Figs: 5, 6, 7 and 8 of the Drawing.
:
When an engine is required to run either way I divide the slide E into two
compartments (see Fig: 7) into either of which steam is admitted and I also make
two passages in the rocking valve H on different planes (see Fig: 5). The
The slide E
exhaust ports I, I' are fitted with slides which are worked by levers.
in Fig 5 is cast with a cover having a space, L, into which steam is admitted to
keep it down to the piston; but instead of steain I may use may use outside
eccentrics, or springs or other mechanism for the same purpose.
Hitherto I have confined myself to the description of a single cylinder rotary

page_text: As
engine, but it will be obvious that the same description is equally applicable to one
having two cylinders of which the pistons are fixed in opposite directions, thus
avoiding any dead centre; so that when one piston is at the top the other is at the
bottom of the cylinders. In this arrangement however I dispense with the use of
steam as a means for keeping the abutment rocking valves down on the face of the
pistons, and in lieu thereof I employ a lever arrangement, as shown in Fig: 8.
these pistons have similar diameters and throws, the travel of the slides is
identical; in opposite directions, one descending, the other ascending. The cylinders
and the slide boxes are divided by a partition M into which I screw a stud N,
fitted with a nut and having a loose collar O, which has two V points. A double
lever P works under theso points, at both ends of which lever are other double
V pieces, which bear upon the top of the slides E, E; a spring washer Q is placed
between the nut and the loose collar O. By screwing down, the nut into the
spring washer the strain caused thereby is communicated to the lever P through
the double V pieces to the slides D, D', and the rocking valves H, H', and the
amount of pressure on the pistons regulated at will.
In order to compensate for the wear of the piston against the inner surface of
the cylinder; in lieu of securing the piston direct to the axle or shaft I provido
the same with a rectangular opening T arranged so as to fit and be capable of
sliding upon a squaro S, formed upon the shaft or axle B; sufficient clearance
being provided within the opening in the pistons to enable the same to be moved
slightly in a transverse direction to the axle, by means of the spiral springs U, or
equivalent device, as shown Fig: 5.
Having now described and ascertained the nature of my said Invention and in
what manner the same is or may be performed, I would have it understood that I
do not confine myself to the precise details herein set forth and illustrated on the
accompanying Sheet of Drawing, as such may be modified while retaining the
essential characteristics of my Invention and that what
I Claim as secured to me by the hereinbefore in part recited Letters Patent
1S-
Firstly: In a rotary steam engine, the use of a slide working in a radial position
to the cylinder in combination with a rocking valve working in a transverse
direction to it, actuated by the piston substantially as hereinbefore described and
shown and for the purpose specified.
Secondly-The arrangement of the steam ports within the slide and the rocking
valve for reversing the engine, substantially as herein before described and shown
Figs: 5, 6 and 7 of the Drawing.
Thirdly-The general arrangement and combination of the several parts of the
Engine as described and shown.
In Witness whereof I the said John Pinchbeck have hereunto set my hand
and seal this Seventeenth day of January in the Year of Our Lord One
thousand Eight hundred and Eighty three.
JOHN PINCHBECK (L.S.)