CERTAIN IMPROVEMENTS IN METALLIC PISTONS
Year: 1858

page_text: LETTERS PATENT to John Swain, of Hyde, in the County of Chester,
Ironfounder, and Matthew Swain, of Dukinfield, in the same County,
Engineer, for the Invention of "CERTAIN IMPROVEMENTS IN METALLIC
PISTONS."
Sealed the 1st November 1858, and dated the 4th May 1858.
PROVISIONAL SPECIFICATION left by the said John Swain and Matthew
Swain at the Office of the Commissioners of Patents, with their Peti-
tion, on the 4th May 1858.
We, JOHN SWAIN, of Hyde, in the County of Chester, Ironfounder, and
MATTHEW SWAIN, of Dukinfield, in the same County, Engineer, do hereby
declare the nature of the said Invention for "CERTAIN IMPROVEMENTS IN
METALLIC PISTONS," to be as follows:-
Our improvements relate to a novel description of spring packing, to
be employed in connection with pistons whether used for steam cylinders,
or for the purposes of pumping, or for other purposes to which it may be
applicable.
The improved packing consists in a circular ring of the same diameter as
the piston, its periphery having a V edge of any required angle or bevil; at
any number of points around its circumference the ring is disunited or opened,
and the segments so formed are connected by smaller rings or circles cast or
formed within the large ring at the point of disunion, which allow the large

page_text: ring to spring elastically; this ring is placed between an upper and lower split
packing ring having bevilled surfaces, and the rings and spring wedge are
placed between the upper and lower plates of the piston, the upper plate being
bolted down upon the packing by means of bolts passing into a central block
in the piston, which retains the spring wedge in its position, and by means of
the pressure of such bolts the elastic annular wedge may be caused to expand
the packing rings so as to keep them tight against the internal surface of the
cylinder, and so produce an elastic steam or water-tight packing..
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Swain and Matthew Swain in the Great Seal Patent
Office on the 4th November 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
SWAIN, of Hyde, in the County of Chester, Ironfounder, and MATTHEW SWAIN,
of Dukinfield, in the same County, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of May, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
John Swain and Matthew Swain, Her especial license that we, the said
John Swain and Matthew. Swain, our executors, administrators, and assigns,
or such others as we, the said John Swain and Matthew Swain, our execu-
tors, 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, 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 "CERTAIN IMPROVEMENTS IN METALLIC PISTONS,"
upon the condition, amongst others, that we, the said John Swain and
Matthew Swain, by an instrument in writing under our 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 we, the said John Swain and Matthew Swain,
do hereby declare the nature of our 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 accompanying Drawings (that is to say):-

page_text: Our improvements relate to a novel description of spring packing to be
employed in connection with pistons whether used for steam cylinders, or for
the purposes of pumping, or for other purposes to which it may be applicable.
The improved packing consists in a circular ring of the same diameter as
the piston, its periphery having a V edge of any required angle or bevil; at
any number of points around its circumference the ring is distended or opened,
and the segments so formed are connected by smaller rings, circles, or other
shaped connections, cast or otherwise formed within the large ring at the points
of disunion which allows the large ring to spring elastically; this ring is placed
between an upper and lower split packing ring having bevilled, and the ring
and spring wedge are placed between the upper and lower plates of the
piston, the upper plate being bolted down upon the packing by means of bolts
passing into a central block in the piston, which block retains the spring
wedge in its position; and by means of the pressure of such bolts the elastic
annular wedge may be caused to expand the packing rings so as to keep them
tight against the internal surface of the cylinder, and so produce an elastic
steam or water-tight packing.
In order that the Invention may be better understood and explained in
detail, I have hereunto attached a Sheet of Drawing made about full size, and
having similar letters of reference marked upon corresponding parts of the
apparatus.
Fig. 1 is a plan view of the improved piston having the cover removed to
shew the position of the elastic ring; Fig. 2 is a sectional elevation taken
through the line A, B; and Fig. 3 is a detached plan view of the elastic ring
when unconfined by the packing rings. In Fig. 2, a, a, are the upper and
lower plates of the piston; and b, the piston rod passing through the lower
plate and the central block c, which cast or otherwise secured upon the said
plate, and is suitably formed to receive the lesser or connecting rings d, d, of
the elastic annular wedge e, e; the screws f, f, secure the top plate by being
screwed into the block c, and the packing rings g, g, are brought together and
compress the elastic ring by such screws. When the piston is thus bolted
together and ready for use, the elastic ring thus compressed will exert a
pressure outwards upon the two packing rings, and thus keep them constantly
pressed against the sides of the cylinder, thus forming a perfectly steam-tight
or water-tight piston. In instances where the internal surface of the cylinder
is not perfectly circular, the ring will yield elastically to such uneven or unequal
surface, so as still to maintain a steam or water-tight contact between the
cylinder and piston.
Having now described the nature of the said Invention, together with the

page_text: method of performing the same, I wish it to be distinctly understood that I
claim the novel application, employment, and use of an internal elastic ring,
acting as an annular wedge for the purpose of expanding the split packing
rings of the piston, whether the connections forming part of such clastic ring
be made circular, oval, or in any other shape which shall produce the same
effect.
In witness whereof, we, the said John Swain and Matthew Swain,
have hereunto set our hands and seals, this Third day of November,
in the year of our Lord One thousand eight hundred and fifty-eight.
JOHN SWAIN.
(L.S.)
MATTHEW SWAIN. (L.S.)