IMPROVEMENTS IN PISTONS FOR STEAM AND OTHER MOTIVE ENGINES
Year: 1869

page_text: LETTERS PATENT to Oswald Rose, of Bolton, in the County of Lan-
caster, Engineer, for the Invention of "IMPROVEMENTS IN PISTONS
FOR STEAM AND OTHER MOTIVE ENGINES."
Sealed the 10th May 1870, and dated the 12th November 1869.
PROVISIONAL SPECIFICATION left by the said Oswald Rose at the
Office of the Commissioners of Patents, with his Petition, on the
12th November 1869.
I, OSWALD ROSE, of Bolton, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
PISTONS FOR STEAM AND OTHER MOTIVE ENGINES," to be as follows:-
The object of my Invention is to produce a light and strong piston,
reduce friction, render the wear of piston and cylinder equal and
uniform, and to dispense with screws or springs used in common pistons.
And my Invention consists in an arrangement of parts which allows the
pressure of the steam or other acting fluid to get between the body of

page_text: the piston and the metallic segments so as to force them outwards
against the cylinder, one set of segments acting for one side of the
piston and another set for the other side of the piston. The piston is
formed with a junk ring on each side turned up to fit as steam-tight as
possible to the body of the piston, being secured thereto by bolts, and
in the centre, there is a projection from the body of the piston which
forms a partition between the packing segments on one side of the
piston and those on the other side, which segments are turned up and
made to fit steam-tight between the partition and junk rings. The
spaces between the segments are closed by V pieces, as is well under-
stood, or by other well-known arrangements, or two sets of segments are
used, one covering the spaces between the others. The steam or acting
fluid is admitted between the body of the piston and the segments
through one or more small holes in the body of the piston, there being a
separate hole or set of holes for the segments on each side of the piston.
The metallic segments arranged as above described will be in equilibrium
if the pressure of the steam or fluid gets between the segments and the
side of the cylinder, as it may do. And an important part of my Invention
consists in causing the acting pressure of the steam or fluid to become
effective by arranging cavities in the segments between the partition
ánd segments or the junk rings and segments which are made to com-
municate with the vacuum or low pressure side of the piston, that is the
cavities in the segments on one side of the piston communicate with the
cylinder on the other side of the piston, each opening having a valve
applied so as to allow the cavities to be exhausted or reduced to the
lowest pressure, but to prevent, the high or acting pressures from getting
into them as they will be alternately exposed to the acting and exhaust
pressures. With this arrangement the acting pressures tending to
force the segments outwards towards the sides of the cylinder, and
also against the partition or junk ring, will be in excess of the exhaust
pressures acting in the contrary direction, and these acting pressures
will depend upon and vary with the difference of pressure between
the.acting and exhaust pressures.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Oswald Rose in the Great Seal Patent Office on
the 12th May 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, OSWALD
ROSE, of Bolton, in the County of Lancaster, Engineer, send greeting.
:
:
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of November, in the year
of our Lord One thousand cight hundred and sixty-nine, in the thirty-,
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Oswald Rose, Her special license that
I, the said Oswald Rose, my executors, administrators, and assigns,
or such others as I, the said Oswald Rose, my executors, adminis-
trators, 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,.
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 PISTONS FOR STEAII
AND OTHER MOTIVE ENGINES," upon the condition (amongst others) that
I, the said Oswald Rose, by an instrument in writing under my hand
and scal, 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 Oswald Rose, 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 and the accompanying Drawings (that is to say) :-
The object of my Invention is to produce a light and strong piston,
reduce friction, and render the wear of the piston and cylinder equal and
uniform and to dispense with screws or springs used in common pistons..
And my Invention consists in an arrangement and combination of parts
which allows the pressure of the steam or other acting fluid to get
between the body of the piston and the metallic segments so as to
force them outwards against the cylinder and at the same time against
a partition formed on the piston, there boing two sets of segments, one on

page_text: cach side of the partition; but the peculiar feature of my Invention
consists in the arrangement of the segments so that the excess of
pressure of steam or fluid on one side of the piston over that on the
other side will produce the force required to press the segments against
the sides of the cylinder and the partition upon the piston. Without this
arrangement the segments would be in equilibrium in respect to the
acting pressure and there would be no force acting to push them outwards.
To accomplish this object hollows are formed in the segments which
may be termed vacuum or low pressure cavities, the cavity for one side
of the piston communicating with the cylinder on the opposite side of
the piston so as to allow the cavities to be exhausted with the steam or
other motive fluid. The entrance to these cavities may have valves
applied to them, which will open to allow fluid to pass out but will close.
to prevent the admission of the acting high-pressure fluid. The said
cavities may be arranged to communicate through a hollow in the
piston rod with the atmosphere if desired.
My Invention will be more fully understood by reference to the
accompanying Drawings and the following explanation :-
Fig. 1 is a diametrical section of one modification of my improved
piston; Fig. 2 is a partial section and edge view, and Fig. 3 is a side
view of the piston with part of the junk ring supposed broken away.
a is the body of the piston screwed on the piston rod (a¹). The body
of the piston is equal in diameter to the cylinder it is intended to fit.
There is a set of segments (6) on each side of the partition part of the
piston, and each set of segments is kept as close to the partition as
possible by the junk rings (c), which are secured by bolts (d) passing
through the piston or by set screws. The joints between the segments
are closed by V pieces (6¹) as is well understood. It will be seen that a
step projection (a²) is made on each side of the partition of the piston, and
that a similar step (6) is made on the segments, and this forms a cavity
(e) on each side all round the piston. The faces of the projections on
the segments and partition are ground to form a tight joint. Tho
cavity (e) on one side may be made to communicate with the opposite
side of the piston, or if valves. are used both cavities may be made to
communicate one with the other by a passage (e³), as shewn in Fig. 1,
the valves (f) being placed as shown to open outwards. A space (g).
is formed in the inner face of the segments, and holes (9') are formed
in the body of the piston to freely admit the steam or other fluid,

page_text: which will thus act to force the segments outwards and against the.
partition.
Fig. 4 is a diametrical section, Fig. 5 a partial section and
edge view, and Fig. 6 a side view with the junk ring removed of
another modification arranged so that the body of the piston may be
conveniently secured to the piston rod by a cottar, and so that all the
segments (6) forming the piston may be removed and replaced from
one side of it. a is the body of the piston, which may be secured to
the rod (a) by the cottar (a³). The body of the piston in this caso
forms one of the junk rings. The partition part (4) is made separate
from the body of the piston, and it is ground to form a tight joint
between the body of the piston and the other junk ring (c) when
secured by bolts passing through the piston. The loose junk ring (c)
is also ground to form a tight joint with the body of the piston and tho
partition part (%) so that the piston forms a hollow steam-tight box and
communicates by passages (e¹) with the vacuum or low-pressuro
cavities (e) as shown. A valve (f) is placed on each side, opening
outwards from the hollow of the piston as shown, and openings (g¹) are
made to admit the acting steam or fluid to the inner space (9) of the
segments to force them outwards and against the partition. Spaces (9³)
are also left between the junk rings and the segments to give free
admission to the steam or fluid.
Fig. 7 is a diametrical section of a piston according to another
modification, which is similar to the piston represented by Figs. 1, 2,
and 3, except that the cavities (e) are made to communicate through
the passage (e) with the atmosphere through a hollow in the piston
rod (a) as shown, and the segments (b) are made broader to occupy the
thickness of the junk rings (c), which are reduced in diameter. This
form of segment is shown-enlarged by Fig. 8, a cross section; a detached
cross section of a segment is also shown by Fig. 9.
I have now particularly described the nature of my Invention, and
the mode of carrying the same into effect, and claim as my Invention,―
Firstly. The combination and arrangement of parts forming the
improved piston as herein-before described and illustrated by the
Drawings.
Secondly. The system. or mode of pressing the segments outwards
against the cylinder and against the partition upon the piston by the
pressure acting on one side of the piston which is in excess of that on

page_text: the other side of the piston, substantially as herein-before described and
illustrated by the Drawings.
In witness whereof, I, the said Oswald Rose, have hereunto sct
my hand and scal, this Seventh day of May, in the year of our
Lord One thousand eight hundred and seventy.
Witness,
PETER J. LIVSEY,
Patent Agent,
Manchester.
OSWALD ROSE. (L.s.)