CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF METALLIC PISTONS
Year: 1843

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BARKER, of Manchester, in the County of Lancaster, Millwright, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twentieth day of March, in the sixth year of Her reign, and
in the year of our Lord One thousand eight hundred and forty-three, did, for
Herself, Her heirs and successors, give and grant unto me, the William
Barker, Her especial licence, full power, sole privilege and authority, that I,
the said William Barker, my executors, administrators, and assigns, and such
others as I, the said William Barker, my executors, administrators, and 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 and Wales, and the Town of
Berwick-upon-Tweed, and in all the Islands of Jersey, Guernsey, Alderney,
Sark, and Man, and also within all Her Majesty's Colonies and Plantations
abroad, my Invention of "CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF
METALLIC PISTONS;" in which said Letters Patent is contained a proviso that I,
the said William Barker, shall cause a particular description of the nature of
my said Invention, and in what manner the same is to be performed, to be
enrolled in Her Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and at
large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, 1, the said
-William Barker, do-hereby declare that the nature of my-said Invention, and
and the manner in which the same is to be performed, is particularly described
and ascertained in and by the Drawings hereto annexed, and the following
explanation thereof (that is to say):-
:-
My Improvements in the Construction of Metallic Pistons consist, firstly,
in the peculiar formation or construction of that part of such pistons called the
"packing;" and, secondly, in the mode of application and use of such novel
and peculiar construction of packing, for the purpose of rendering metallic
pistons perfectly self-adjusting, and also, steam, air, or water tight, either
when employed in steam engines or air pumps, or in any other situation where
a perfectly tight packing is required. And in order that my Invention
may
perfectly understood, I have attached to these presents a sheet of Drawings
representing distinctly my improvements in the construction of metallic pistons,
and the respective applications, thereof.
be
Fig. 1 is an external representation of a piston of a steam engine. Fig. 2
is a plan or top view of the same, with the cap or top plate removed. Fig. 3, a
section taken transversely through the piston, and Fig. 4, an external view of
the metallic packing expanded, or seen as removed from the piston. Fig. 5 is
an external view, and Fig. 6, a sectional view of a similar piston, but slightly
modified in its construction; similar letters of reference indicate correspond-
ing parts of the apparatus in all the Figures. a, a, is the piston rod; b, b, is
the piston with its cap or top plate c, c, and its bottom plate c*, c*, between
which the improved metallic packing d, d, is placed, being in this mode of
application of a somewhat larger diameter than the piston, in order that there
may be some degree of elasticity when contracted and placed within the
cylinder in which it is intended to work. It will be observed in the plan and
sectional views, that there is a clear open space e, e, e, e, left entirely around the
piston between the body of the piston b, b, and the metallic packing d, d, and
this space allows for any variation or self-adjustment in the metallic packing,
as required, and is essential to the application and use of my improved packing.
The manner in which I construct or form the packing, and which I consider to
be the only feature requiring a detailed description after an inspection of
the Drawing, will be more clearly understood by referring to the diagram,
Fig. 7, which exhibits the outline of the packing, supposing the same to be
extended upon a plane, and this figure is shewn, that any competent mechanic
may understand how the packing is to be produced or turned in the lathe.
A perfect ring of cast iron or other suitable metal is to be placed in the lathe,
and after drilling small holes as starting and stopping places for the cutting

page_text: tool, a cut is to be made, which shall be taken in an oblique direction
(produced by the ordinary traverse motion of a slide lathe) until half way
round the ring, when the cutting tool must stop cutting at the drilled hole in
that situation, and a second cut made in a still more oblique direction and
produced by changing the speed of the traverse motion, which will cut or form
the line or angle y, z; the worm or screw is then to be cut parallel, as from
w to x, and the ring is then to be reversed in the lathe when the other oblique
cuts are to be made exactly as before, and the reversed angle produced, as
from w to v. It will be observed that the metal to be cut out of the centre
part of the ring is three times the width of that removed at the top and
bottom, and thus an equal degree of elasticity is left in all parts of the ring of
packing. By turning out or removing such portions of metal from the ring
it will be left as the thread of a screw, and when compressed it will be found
to have attained the desired elasticity; small pieces are then to be cut from
off the extremities f, f, leaving a space enabling the ring to be contracted in
diameter also. The packing or screwed ring is then to be contracted by
clamps both in its diameter and width, and turned or finished to the intended
width of the piston and the diameter of the cylinder in which it is to be
employed; small recesses or channels g, g, are to be made in the ends of the
packing, to be filled up by moveable stop pieces h, h, in order to prevent the
passage of the steam within the packing. In Figures 5 and 6 I have repre-
sented a piston with my improved. metallic packing enclosed within rings of
brass h*, h*, to be used in those situations where it is preferred.
Having now described my improvements in the construction of metallic
pistons, I wish it to be particularly understood that I claim as my Invention
the peculiar construction and formation of the packing thereof, and its manner
of application and use, so as to be perfectly and equally elastic throughout and
self-adjusting, as herein particularly set forth and exhibited in the Drawings
attached to these presents, whether such pistons are used in steam engines, air
pumps, or any other situation where a perfectly steam, air, or water-tight
packing is required.
In witness whereof, I, the said William Barker, have hereunto set my
hand and seal, the Nineteenth day of September, in the year of our
Lord One thousand eight hundred and forty-three.
WILLIAM (L.s.) BARKER.

page_text: AND BE IT REMEMBERED, that on the same Nineteenth day of Septem-
ber, in the year above mentioned, the aforesaid William Barker came before
our Lady the Queen in Her 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 September, in the year above written.