IMPROVED METALLIC PACKING FOR PISTONS AND AIR-PUMP BUCKETS
Year: 1882

page_text: LETTERS PATENT to George Holcroft, of Manchester, in the County of
Lancaster, Engineer, and James Grundy, of Ashton-under-Lyne, in the same
County, Engineer, for an invention of "IMPROVED METALLIC PACKING FOR
PISTONS AND AIR-PUMP BUCKETS."
PROVISIONAL SPECIFICATION left by the said George Holcroft and James
Grundy at the Office of the Commissioners of Patents on the 7th March
1882.
GEORGE HOLCROFT of Manchester in the County of Lancaster Engineer and
JAMES GRUNDY of Ashton-under-Lyne in the same County Engineer "IMPROVED
METALLIC PACKING FOR PISTONS AND AIR-PUMP BUCKETS
"
The object of our invention is to make packing rings for pistons and air-pump
buckets that will wear uniformly and that will press equally on all parts of their
periphery.
We make an eccentric ring the outer portion of which is circular and concentric
to the centre of the piston rod: the ring being cut or divided at the thinnest part
of its circumference so as to form a lap joint requiring no loose stop bits. The
ring thus formed requires no inner springs, we use by preference several rings
fitted in separate grooves in the piston, or in a loose annular block, fitted on the
piston.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Holcroft and James Grundy in the Great Seal Patent
Office on the 4th September 1882.
GEORGE HOLCROFT of Manchester in the County of Lancaster Engineer and
"IMPROVED
JAMES GRUNDY of Ashton-under-Lyne in the same County, Engineer
METALLIC PACKING FOR PISTONS AND AIR PUMP BUCKETS
"
The object of our invention is to make packing rings for pistons and air pump
buckets that will wear uniformly and that will press equally at all parts of their
periphery, and that will require no additional spring or springs.
We make an eccentric ring the outer portion of which is circular and concentric
to the centre of the piston rod: the ring being cut or divided at the thinnest part
of its circumference so as to form a lap joint requiring no loose stop bits. The
ring thus formed requires no inner springs: we use by preference several rings
fitted in separate grooves in the piston, or in a loose annular block fitted on the
piston.
And in order that our invention may be fully understood and readily carried
into effect we will describe the accompanying sheet of drawings reference being
had to the figures and letters marked thereon.
Fig. 1 is an elevation and Fig. 2 is a plan of our improved packing ring.
The thinnest part of the ring is where the joint is formed and at the thickest
part, which is diametrically opposite the ring is about two-thirds thicker: these
proportions may be varied according to the diameter of the ring: although we
have shown a lap joint any other form of joint may be made.
Fig. 3 shows in section the form of piston we prefer to use with our improved
rings: we employ three rings A each one fitted in an annular groove in the piston
and we dispense with inside springs.
Fig. 4 shows an old piston to which our improved packing rings are applied we
use an annular block b on which we fit our improved rings and place them on the
piston head and then secure the junk ring in its place.
Our improved packing rings wear uniformly and are much more durable than
rings of the ordinary form. No springs and no stop pieces are required.
Having stated the nature of our invention and described the manner of
performing the same.
We declare that we claim.
1. The improved eccentric packing ring substantially as and for the purpose
herein described and as shown on Figs. 1, 2 and 3.
2. The combination with an annular block of eccentric rings substantially as
described and as shown at Fig. 4.
In witness whereof we the said George Holcroft and James Grundy have
hereunto set our hands and seals this second day of September One
thousand eight hundred and eighty-two.