IMPROVEMENTS IN METALLIC PACKINGS FOR PISTONS, AIR PUMP BUCKETS, VALVES, AND OTHER PURPOSES
Year: 1874

page_text: LETTERS PATENT to John Johnson, of Lower Broughton, near the
City of Manchester, Millwright and Engineer, and Edward Andrew,
of the City of Manchester, Public Accountant, for the Invention of
"IMPROVEMENTS IN METALLIC PACKINGS FOR PISTONS, AIR PUMP BUCKETS,
VALVES, AND OTHER PURPOSES."
Scaled the 26th February 1875, and dated the 1st September 1874.
PROVISIONAL SPECIFICATION left by the said John Johnson and
Edward Andrew at the Office of the Commissioners of Patents,
with their Petition, on the 1st September 1874.
WC, JOHN JOHNSON, of Lower Broughton, near the City of Man-
chester, Millwright and Engineer, and EDWARD ANDREW, of the City of
Manchester, Public Accountant, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN METALLIC PACKINGS FOR PISTONS, AIR
PUMP BUCKETS, VALVES, AND OTHER PURPOSES," to be as follows:―
i
Our improved metallic packing consists of two taper eccentric rings
which fit into each other, and are cut through in the thinnest part.

page_text: These rings are nicked or provided with grooves in the direction of the
axis, the said grooves diminishing in depth as they approach the thin
part of the rings. The nicks or grooves render the packing rings elastic
circumferentially, and thus ensure a good fit of the piston to the
cylinder, and the end pressure of the packing is obtained by the taper
of the rings.
In order to prevent the passage of the steam at the joint of the outer
ring the taper part of the outer circumferences of the internal ring is
turned off to fit the cylinder. By this means the joint pieces usually
required are dispensed with. A pin passing through the outer ring holds
the inner ring, thereby preventing it getting out of place.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Johnson and Edward Andrew in the Great
Seal Patent Office on the 1st March 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
JOHNSON, of Lower Broughton, near the City of Manchester, Millwright
and Engineer, and EDWARD ANDREW, of the City of Manchester, Public
Accountant, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of September, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto us, the said John Johnson and Edward
Andrew, Her special licence that we, the said John Johnson and
Edward Andrew, our executors, administrators, and assigns, or such
others as we, the said John Johnson and Edward Andrew, our
executors, administrators, and assigns, should at any time agree with
and no others, from time to time and at times all 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 METALLIC PACKINGS FOR PISTONS, AIR PUMP BUCKETS,
VALVES, AND OTHER PURPOSES," upon the condition (amongst others) that
we, the said John Johnson and Edward Andrew, our cxccutors or

page_text: administrators, by an instrument in writing under our, or their, or one
of our or 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.
NOW KNOW YE, that we, the said John Johnson and Edward
Andrew, 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. (that is to say)
Our improved metallic packing consists of two taper eccentric rings,
which fit into each other, and are cut through in the thinnest parts.
These rings are nicked or provided with grooves in the direction of the
axis, the said grooves diminishing in depth as they approach the thin
part of the rings. The nicks or grooves render the packing rings, elastic
circumferentially, and thus ensure a good fit of the piston to the cylinder,
and the end pressure of the packing is obtained by the taper of thẻ
rings.
In order to prevent the passage of the steam at the joint of the outer
ring the taper part of the outer circumference of the internal ring is
turned off to fit the cylinder. By this means the joint pieces usually
required are dispensed with. A pin passing through the outer ring holds
the inner ring, thereby preventing it getting out of place.
And in order that our Invention may be fully understood, and readily
carried into operation, we will proceed to describe the accompanying
Sheet of Drawings, reference being had to the figures and letters marked
thereon.
Fig. 1 is a plan of the piston with the lid removed; Fig. 2 is a trans-
verse section; Fig. 3 is a plan of the outer packing ring; and Fig. 4, an
elevation of the same.
In Figs. 1 and 2 a is the piston rod; b, the body of the piston; and c
the lid, which is held down by the bolts d, d, as in pistons of the ordinary
construction; e and fare two taper eccentric rings forming the improved
metallic packing; these rings fit into each other, and they are cut
through diagonally at their thinnest parts. The packing rings are
provided with grooves in the direction of their axes, the said grooves

page_text: diminishing in depth from the thick part of the rings as they approach
the thin part. The object of these grooves is to render the packing rings
elastic circumferentially, thereby ensuring a good fit of the piston in the
cylinder. The end pressure of the packing rings against the body of the
piston and the lid is obtained by the taper of the rings.
In order to prevent the passage of the steam at the joint of the outer
packing ring e the taper part of the outer circumference of the ring ƒ is
turned off to fit the cylinder; by this means the usual joint pieces are
dispensed with. The packing rings are held in their relative positions
by the pin h, shewn in Fig. 2.
Although we have only shewn one improved metallic packing as applied
to the piston of a steam cylinder, we wish to remark that it may be
applied to packing air pump buckets, circular valves, and for other similar
purposes.
Having thus stated the nature of our Invention, and described a con-
venient mode of performing the same, we wish it to be undestood that
we do not intend to limit ourselves to the details given; we claim,-
First. The improved metallic packings, as shewn and described, in
which the circumferential and lateral pressures are obtained by the use
of two taper eccentric rings.
Secondly. The mode of preventing the passage of steam without the
aid of filling up. pieces, as shewn and described in reference to Fig. 4.
In witness whereof, I, the said Edward Andrew, for myself, and on
behalf of the said John Johnson, have hereto set my hand and
seal, this this Twenty-fifth day of February, One thousand eight
hundred and seventy-five.