Ax ELASTIC METALLIC PISTON, OR PACKING FOR PISTONS, TO BE APPLIED EITHER EXTERNALLY OR INTERNALLY TO CYLINDERS
Year: 1823

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
JESSOP, of Butterley Hall, in the County of Derby, Ironmaster, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-seventh day of March, in the fourth year of His reign, did,
for Himself, His heirs and successors, give and grant unto me, the said William
Jessop, my executors, administrators, and assigns, His especial licence, that
I, the said William Jessop, my executors, administrators, and assigns, or such
others as I, the said William Jessop, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, my Invention of "Ax ELASTIC METALLIC PISTON, OR
PACKING FOR PISTONS, TO BE APPLIED EITHER EXTERNALLY OR INTERNALLY TO
CYLINDERS;" in which Letters Patent there is contained a proviso obliging
me, the said William Jessop, by an instrument in writing under my hand
and seal, particularly to describe and ascertain the nature of my said Inven-
tion, and in what manner the same is to be performed, and to cause the
same to be inrolled in His Majesty's High Court of Chancery within two
calendar months then next, as in and by the same, reference being thereunto
had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Jessop, do, by this instrument in writing under my hand and seal,

page_text: declare that the nature of my said Invention, and the manner in which the
same is to be performed is as follows, that is to say:-
My Invention consists in the application of an elastic metallic cylindric ring
(formed by a spiral of two, three, or any other number of circumvolutions,
after the manner of a screw) to be used as a substitute for hemp, leather, or
other substances as packing for cylinders, pistons, plungers, rods, buckets, or
other thing to prevent the escape of steam, air, water, or other fluid, as the
case may be, as well as to lessen the friction thereof, and to increase the effect
of power on steam engines, pumps, and other machines to which it is applied.
This I effect by making such spiril cylindric ring of a greater or less diameter
than the cylindric body against which it is to act, so that by its expansive or
contractile power it shall ensure the touching and fitting of the surfaces
without so much pressure as to cause unnecessary friction. The spiral ring is
to be adapted and fitted in a groove or recess, or situation on the piston,
bucket, stuffing box, or other part to which it is applied, which may be done
by any of the methods commonly used and well understood. The spiral ring
may be manufactured by different means, but I have found the following con-
venient: I make of brass or other metal, or mixture of metals of proper
quality, a cylindric ring varying in its dimensions according to the circum-
stances of its application, which ring I divide or cut in a spiral direction on its
cylindric edge into two, three, or such other number of circumvolutions as may
be necessary or convenient.
The Drawing in the margin shews the elastic metallic ring, and its appli-
cation to a piston, from which its general application as a packing may be
understood.
In witness whereof, I have hereunto set my hand and seal, this Tenth
day of May. One thousand eight hundred and twenty thron
WILLIAM (1.8.) JESSOP.
Signed, sealed, and delivered (being
first duly stamped) in the pre-
sence of
HUGH SCOTT,
of Butterley, in the County of Derby,
Esq.

page_text: AND BE IT REMEMBERED, that on the Seventeenth day of May, in
the year above written, the aforesaid William Jessop came before our Lord
the King in His Chancery, and acknowledged the Specification aforesaid,
and all and every thing therein contained, in form above written. And also
the Specification aforesaid was stamped according to the tenor of the Statute
in that case made and provided.
Inrolled the Twentieth day of May, in the year above written.