IMPROVEMENTS IN THE CONSTRUCTION OF ROTARY ENGINES AND PUMPS
Year: 1868

page_text: LETTERS PATENT to John Cooke, of Darlington, in the County of
Durham, Mining Engineer, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF ROTARY ENGINES AND PUMPS."
Sealed the 17th October 1868, and dated the 20th April 1868.
PROVISIONAL SPECIFICATION left by the said John Cooke at the
Office of the Commissioners of Patents, with his Petition, on the
20th April 1868.
I, JOHN COOKE, of Darlington, in the County of Durham, Mining
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF ROTARY PUMPS AND ENGINES," to be
as follows:-
This Invention consists of a novel construction and arrangement of
such rotary pumps and engines as have a cylindrical piston rotating
eccentrically in a cylinder, and which have also a shutter constantly
kept near to the same, and passing in and out through a suitable port
in the circumference of the cylinder of the same length as the piston,

page_text: in such a manner as to divide the inlet from the outlet of the rotary
pump or engine.
This Invention is especially applicable to blowing and exhausting
machines, and to pumps and water engines, but is also adapted to
engines in which the motive power is derived from an elastic fluid.
In rotary pumps and engines of this class, as hitherto constructed
independently of this Invention, the shutter is a plane which passes
through a slot in what may be termed the shutter box into guides
which form, together with the slot, the support to such shutter against
the lateral pressure brought to bear on it. In this method of con-
struction the slot is very difficult to pack. In such pumps and engines
the shutter is moved either by the action of the piston itself, against
which it is pressed by any suitable means, being thus the source of
considerable friction and imperfection, or sometimes by cams from the
engine, so as to make it move equably with the piston.
By the present Invention the objection to the shutter is removed by
making it describe an arc of a circle, which avoids the slot in the
shutter box, the axis of such arc being a bar parallel to the cylinder
and passing through a stuffing box at the end of the shutter box, the
same being so placed as to form a sufficient guide and support for
the shutter, and so actuated from without the shutter box by a lever
as to form the means, of reciprocating the same, and also so placed as
to secure a favourable angle of the shutter with the piston. The lever
which actuates the axis bar is made of the same length as the radius
of the arc which is described by the shutter at its line of contact, perfect
or approximate, with the piston, and is so placed, by preference, as to
have one end fitting the axis bar, while the other end at its centre
coincides with the line so produced. To this other end is attached the
connecting rod, the length of which is equal to the radius of the piston,
and is actuated by a crank pin or eccentric, the centre of which is the
centre line of the piston. By this construction an equable motion of
the shutter with the piston at their said line of contact is produced,
independently of any pressure of the one upon the other. If convenient,
the shutter is so constructed (as herein-after mentioned) as itself to
prevent leakage while the piston is passing the port, but any clack or
other valves or slides adapted for the purpose may be used for the pumps
or engines to which this Invention is applied, whether the shutter be
so constructed or not. In cases in which packing is not used, and in

page_text: which the shutter does not touch. the piston, the connecting rod is made
a little longer than the radius of the piston, and in some cases the
shutter is constructed as a plane, which is reciprocated, by any suitable
means, from the end of the connecting rod, which itself reciprocates
in the same plane as the shutter. In those cases in which packing is
used, the length of the connecting rod and of the lever may be varied
so as to suit the packing. The packing of the piston may be effected
as usual in rotary engines, but it is preferred to place upon an inner
cylinder or frame in any convenient way one or more rings or hoops
so as to make the piston touch the cylinder, and to make the ends of
the cylinder revolve with the piston, packing them externally, so as,
when required, to keep the piston opposite the port. The packing of
the line of contact of the shutter with the piston is by preference
cylindrical and of a suitable diameter, but may be so made as only to
approximate to a cylindrical surface in its rubbing part. The packing
of the shutter ends is effected from the interior of the arc described by
the shutter by screws fixed on the same. The packing of the exterior
arc of the shutter, which is made true to the centre of the axis bar, is
adjusted against it in any suitable manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Cooke in the Great Seal Patent Office on
the 19th October 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
COOKE, of Darlington, in the County of Durham, Mining Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of April, in the year
of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Cooke, Her special licence
that I, the said John Cooke, my executors, administrators, and assigns,
or such others as I, the said John Cooke, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,

page_text: .
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN THE Com-
STRUCTION OF ROTARY ENGINES AND PUMPS," upon the condition (amongst
others) that I, the said John Cooke, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, should particularly 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 Cooke, 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, reference being had to Drawings here-
unto annexed, and to the figures and letters marked thereon, that is to
say:-
My said Invention consists of a novel construction and arrangement
of such rotary pumps and engines as have a cylindrical piston rotating
eccentrically in a cylinder, and which have also a shutter constantly
kept close or near to the same and passing in and out through a suitable
port in the circumference of the cylinder of the same length as the
piston in such a manner as to divide the inlet from the outlet of the
rotary pump or engine.
This Invention is especially applicable to blowing and exhausting
machines and to pumps and water engines, but is also adapted to
engines in which the motive-power is derived from an elastic fluid.
In rotary engines and pumps of this class as hitherto constructed
independently of this Invention, the shutter is a plane which passes
through a slot in what may be termed the "shutter box" into guides
which form together with the slot the support to such shutter against
the lateral pressure brought to bear on it. In this method of con-
struction the slot is very difficult to pack. In such pumps and engines
the shutter is moved either by the action of the piston itself, against
which it is pressed by any suitable means, being thus the source of
considerable friction and imperfection, or sometimes by cams from the
engine so as to make it move equably with the piston.

page_text: By the present Invention the objection to the shutter is removed
by making it describe an arc of a circle which avoids the slot in the
shutter box, the axis of such are being a bar parallel to the cylinder
and passing through a stuffing box at the end of the shutter box, the
same being so placed as to form a sufficient guide and support for
the shutter and so actuated from without the shutter box by a lever
as to form the means of reciprocating the same, and also so placed as
to secure a favourable angle of the shutter with the piston. The lever
which actuates the axis bar is made of the same length as the radius
of the arc which is described by the shutter at its line of contact
perfect or approximate with the piston, and is so placed, by preference,
as to have one end fitting the axis bar, while the other end at its
centre coincides with the said line produced. To this other end is
attached the connecting rod, the length of which is equal to the radius
of the piston, and is actuated by a crank or eccentric the centre of
which is the centre line of the piston. By this construction an equable
motion of the shutter with the piston at their said line of contact is
produced independently of any pressure of the one upon the other.
If convenient the shutter is so constructed as itself to prevent leakage
while the piston is passing the port, but any clack or other valves or
slides adapted for the purpose may be used for the pumps or engines
to which this Invention is applied, whether the shutter be so constructed
or not. The before described method of construction assumes either
that the line of contact of the shutter with the piston is an edge
more or less obtuse, or that elastic packing is used for the same. In
cases in which packing is not used, and in which the shutter does not
touch the piston, the connecting rod is a little longer than the radius
of the piston, and in some cases the shutter is constructed as a plane
which is reciprocated by any suitable means from the end of the
connecting rod which itself reciprocates in the same plane as the
shutter for that purpose. In cases in which packing is used at the
line of contact of the shutter with the piston, and also in some cases
in which it is not so used, it is preferred, particularly if it is non-elastic,
to make the same or the edge of the shutter cylindrical as to its
5. surface in its rubbing part and of a suitable diameter, in which case
the length of the connecting rod and the length and position of the
lever are varied so that their coinciding centres are at or near the
centre line of such cylindrical surface of the edge of the shutter or of
the packing. This packing or shutter edge may however be so made

page_text: as only to approximate to a cylindrical surface in its rubbing part,
and in such case the length of the connecting rod and the length and
position of the lever may be varied to suit the shutter edge. The
packing of the piston may be effected as usual in rotary engines, but
it is preferred to place upon an inner cylinder or frame in any convenient
way one or more rings or hoops such as to make the piston touch the
cylinder, and also when adjustment is required sufficiently eccentric
to admit of this being effected, but when so eccentric it is necessary
to fix on the crank pin a similar eccentric hoop capable of adjustment
to a similar position. It is also preferred to make the cylinder ends
revolve with the piston packing them externally, so as when required
to keep the piston opposite the port. This last method of packing is
not however new and forms no part of the present Invention. The
packing of the shutter ends may be effected from the interior of the
arc described by the shutter by means of screws fixed on the same.
The packing of the exterior arc of the shutter, which is made true to
the centre of the axis bar, is adjusted against it in any suitable way.
The axis bar passes as before mentioned through a stuffing box at the
end of the shutter box.
I will now proceed to refer to the annexed Drawings, which represent
a rotary pump constructed in accordance with this Invention and from
which the nature thereof as herein-before described will be more clearly
understood.
Figure 1 is a horizontal sectional plan through the line A, B, in
cross section shewn at Figure 2, the latter being a vertical section at
the line C, D, in Figure 1; Figure 3 is an end elevation, and Figure 4
is a section through the shutter at the line E, F. In these Figures
the same letters of reference indicate similar parts.
a, is the axle; b, the crank pin; c, the connecting rod; d, the lever;
e, the carriages for the piston axle; f, the carriage for the axis bar;
g, the bed plate; h, the cylinder; i, the piston; j, packing rings on the
same; k, space for allowing the elasticity of the rings; 1, cylinder ends
and nuts for fastening the loose one against the packing rings; m,
glands for packing cylinder ends; n, the axis bar; o, the shutter box;
2, cover for the same; q, leather flap joint; r, inlet holes; sport or a
outlet; is the shutter; u is the end packing of the same; is the
packing of the line of contact held down as shewn; w, is the gland of
the axis bar.

page_text: In Figure 1 the shutter is removed so as to shew the mode of placing
the axis bar, which, where concealed, is shewn with its glands and
stuffing boxes by fine dots. In Figure 2 the shutter is not removed;
Figure 3 shews the connection of the crank pin to the lever which
actuates the axis bar; Figure 4 shews the mode of fixing the end
packing of the shutter.
This Invention admits of several modifications in which the main
principles of construction herein-before described are preserved.
Having thus declared and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I would observe in
conclusion that what I consider novel and original, and therefore claim
as constituting the Invention secured to me by the said herein-before
in part recited Letters Patent is, the combination and arrangement of
parts and mechanism for the purposes aforesaid, substantially as herein-
before set forth and described or any mere modifications thereof.
In witness whereof, I, the said John Cooke, have hereunto set
my hand and seal, this Sixteenth day of October, in the year
of our Lord One thousand eight hundred and sixty-eight.