IMPROVE- MENTS IN PISTONS
Year: 1873

page_text: LETTERS PATENT to James Wilson Martin, of Liverpool, in the
County of Lancaster, Engineer, for the Invention of "IMPROVE-
MENTS IN PISTONS."
Sealed the 10th March 1874, and dated the 11th September 1873.
PROVISIONAL SPECIFICATION left by the said James Wilson
Martin at the Office of the Commissioners of Patents, with his
Petition, on the 11th September 1873.
I, JAMES WILSON MARTIN, of Liverpool, in the County of Lancaster,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PISTONS," to be as follows:-
My Invention consists essentially in forming or constructing the
internal surfaces of both the top and bottom plates of pistons, conical
or tapering, and in providing a split packing ring or rings with corre-
sponding conical or tapering surfaces.

page_text: When the wearing surface of the packing ring or rings require or
requires to be expanded, whether from wear by use or otherwise, the top
and bottom plates are drawn towards each other by a screwed nut on the
piston rod or by bolts or studs and nuts or their equivalents. In this way
a cheap, simple, durable, and reliable piston is obtained.
To prevent steam from passing through the split opening or openings
in the packing ring or rings, I fit each split with a vee piece which
passes across the split and rests on the conical surfaces of the top and
bottom plates.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Wilson Martin in the Great Seal Patent
Office on the 11th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
WILSON MARTIN, of Liverpool, in the County of Lancaster, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of September, in the year of our
LordOne thousand eight hundred and seventy-three, in the thirty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said James Wilson Martin, Her special licence,
that I, the said James Wilson Martin, my executors, administrators,
and assigns, or such others as I, the said James Wilson Martin, 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, 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," upon the condition (amongst others) that I,
the said James Wilson Martin, 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.

page_text: NOW KNOW YE, that I, the said James Wilson Martin, 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 the accompanying
Sheet of illustrative Drawings and to the figures and letters marked
thereon, that is to say :-
My Invention consists essentially in forming or constructing the
internal surfaces of both the top and bottom plates of pistons, conical or
tapering, and in providing a split packing ring or rings with correspond-
ing conical or tapering surfaces.
When the wearing surfaces of the packing ring or rings require or
requires to be expanded, whether from wear by use or otherwise, the top.
and bottom plates are drawn towards each other by a screwed nut on
the piston rod or by bolts or studs and nuts or their equivalents.
this way a cheap, simple, durable, and reliable piston is obtained.
In
To prevent steam from passing through the split opening or openings
in. the packing ring or rings I fit each split with a vee piece, which
passes across the split and rests on the conical surfaces of the top and

page_text: Fig. 5 is a side elevation, and Fig. 6 a plan view of a modification
with two split rings, in which studs and nuts e¹ are used instead of the
nut on the end of the piston rod above described.
Having now described the nature of my said Invention, and parti-
cularized the same in such manner that others will be enabled to carry
the improvements into effect, I claim,-
First. The conical or tapering top and bottom plates a in combination
with packing rings b, substantially as described.
Second. The conical or tapering plates a, packing ring or rings b, and
nut e in combination, substantially as described.
Third. The conical or tapering plates a, packing ring or rings b, nut e,.
and studs f¹, in combination, substantially as described.
Fourth. The conical or tapering plates a, packing ring or rings 6, and
studs and nuts e¹ in combination, substantially as described.
In witness whereof, I, the said James Wilson Martin, have here-
unto set my hand and seal, the Tenth day of March in the
year of our Lord One thousand eight hundred and seventy-four.
.
In the presence of
J. T. KING,
Patent Agent,
Liverpool.
JAMES WILSON MARTIN. (L.S.)