IMPROVEMENTS IN THE CONSTRUCTION OF PISTONS
Year: 1855

page_text: LETTERS PATENT to Thomas Mather, of Preston, in the County of Lan-
caster, Engineer, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION
OF PISTONS."
Sealed the 23rd November 1855, and dated the 26th May 1855.
PROVISIONAL SPECIFICATION left by the said Thomas Mather at the
Office of the Commissioners of Patents, with bis Petition, on the 26th
May 1855.
I, THOMAS MATHER, of Preston, in the County of Lancaster, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
CONSTRUCTION OF PISTONS":
This Invention relates to an improved mode of forming the joint of packing
rings for pistons or plungers working in cylinders, whereby a simple economic
and effective joint is obtained.
The improvement consists in cutting the packing rings obliquely, in place of
straight through the ring, or in a direction of the radius of the ring. The
ring or rings are expanded by means of a wedge piece set up by a screw in
the ordinary manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Mather in the Great Seal Patent Office on the
26th November 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
MATHER, of Preston, in the County of Lancaster, Engineer, send greeting.
WHEREAS Her-most Excellent Majesty Queen Victoria, by.Her Letters
Patent, bearing date the Twenty-sixth day of May, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Mather, Her special licenso that I, the said Thomas Mather,
my executors, administrators, and assigns, or such others as I, the said Thomas
Mather, my executors, administrators, or 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 THE CONSTRUC-
TION OF PISTONS," upon the condition (amongst others) that I, the said Thomas
Mather, by an instrument in writing under my hand and seal, should parti-
cularly describo 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 Thomas Mather, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say :-
My said Invention relates to an improved mode of forming the joint of
packing rings for pistons or plungers working in cylinders, whereby a more
simple, economic, and effective joint is obtained than by the ordinary mode of
junction. The improvement consists in cutting the packing rings obliquely, in
place of straight through the ring, or in a direction of the radius of the ring.
The ring or rings are expanded by means of a wedge piece set up by a screw
in the ordinary manner.
And in order that my said Invention may be fully understood, I shall now
proceed particularly to describe the same, and for that purpose I shall refer to
the Figures on the Sheet of Drawings hereunto annexed, the same letters of
reference indicating corresponding parts throughout both Figures.

page_text: Figure 1 of the Drawings represents a side elevation of a piston and packing
ring formed with my improved joint; and Figure 2 is a corresponding plan of
the under side of the same, with the piston cover removed. A, A, is the metal
packing ring, the junction ends of which are made to overlap each other, and
are cut obliquely in two opposite directions, as shewn at a, b, in place of being
cut radially, or in a direction towards the centre of the ring, as is usually the
case. The two junctions c and d are prevented from communicating, and
thereby allowing the steam to escape, by the interposition of the end of the
single stop or wedge piece B, which is passed through a suitable opening made
through the body of the ring, and serves to tighten up the packing in the
ordinary manner by means of the screw C and spring D.
Having now described and particularly ascertained the nature of my said
Invention, and in what manner the same is or may be used or carried into
effect, I would observe, in conclusion, that I do not confine or restrict myself to
the precise details or arrangements which I have had occasion to describe or
refer to, as many variations may be made therefrom without deviating from
the principles or main features of my said Invention; but what I consider to
be novel and original, and therefore claim as the Invention secured to me
by the herein-before in part recited Letters Patent, is, the construction and
arrangement of metallic packing rings with oblique in place of radial junction
ends, such obliquo junction ends being made to overlap each other, as
herein-before described, and illustrated on my Sheet of Drawings.
In witness whereof, I, the said Thomas Mather, have hereunto set my
hand and seal, the Twenty-third day of November, One thousand eight
hundred and fifty-five.
THOMAS MATHER. (L.S.)