IMPROVEMENTS IN THE CONSTRUCTION OF PISTONS AND PUMP BUCKETS AND IN PACKING FOR THE SAME
Year: 1879

page_text: LETTERS PATENT to Alexander Oldham, of Dukinfield, in the County of
EL
Chester, for the Invention of IMPROVEMENTS IN THE CONSTRUCTION OF
PISTONS AND PUMP BUCKETS AND IN PACKING FOR THE SAME.”
Sealed the 25th May 1880, and dated the 26th November 1879.
PROVISIONAL SPECIFICATION left by the said Alexander Oldham at the
Office of the Commissioners of Patents on the 26th November 1879.
ALEXANDER OLDHAM, of Dukinfield, in the County of Chester. IMPROVEMENTS
IN THE CONSTRUCTION OF PISTONS AND PUMP BUCKETS AND IN PACKING FOR THE
SAME."
"
66
The object of this Invention is to dispense with the loose covers usually employed
to confine the metallic packing of pistons and pump buckets, and thus not only to
economize their construction but to improve their durability by dispensing with
parts liable to become loose in working.
In the first place I employ a single block of cast metal provided with a circum-
ferential groove of the required width and depth to receive the metallic packing,
and without any loose cover or other loose part whatever.
The coil or spring I make of steel, either by means of the process for which
Letters Patent (dated 19th December 1877, No. 4826) were granted to me, or by
any other suitable process.
The packing rings I also make of steel, using by preference what is known as
"Bessemer" steel, and they are either slightly bevilled inside or made with a flange
round one edge (or both bevilled and flanged). These rings are cut, as usual, and
in order to prevent their edges from cutting the inside of the cylinder I round both
their edges off. This also forms a recess (where the edges of the two rings meet)
for retaining tallow or other lubricating material.
The block, coiled spring, and two packing rings having been thus prepared I
proceed as follows:-
I take one end of the spring ring or coil, and by opening it out slightly I pass it
into the groove in the block. I then turn the spring ring or coil round, so that it
gradually screws or worms itself into the circumferential groove of the block.
I then take the steel packing rings, and by opening them out slightly I spring
them over the top and bottom of the block onto the spring ring or coil in the
groove, and the packing of the piston or pump bucket is complete; and it will be
evident that by these means obtain a piston or pump bucket etticiently packed
with metallic packing without the use of loose covers, nuts, bolts, or other separate
parts other than the spring ring or coil and the two packing rings. The manufac-
ture therefore is considerably economized, and the pistons are more durable and less
likely to get out of repair than metallic pistons or pump buckets constructed in the
usual manner with a number of separate parts liable to become loose in working.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alexander Oldham in the Great Seal Patent Office on the 25th
May 1880.
ALEXANDER OLDHAM, of Dukinfield, in the County of Chester. "IMPROVEMENTS
IN THE CONSTRUCTION OF PISTONS AND PUMP BUCKETS AND IN PACKING FOR THE
SAME."
The object of this Invention is to dispense with the loose covers usually employed
to confine the metallic packing of pistons and pump buckets, and thus not only to
economize their construction but to improve their durability by dispensing with
parts liable.to become loose in working.
Such being the nature and object of my said Invention I will now proceed to
describe in detail the manner in which the same is to be or may be performed or
carried into practical effect; and in order that the same may be clearly understood
I have annexed hereunto a Sheet of Drawings illustrative thereof, and have marked
the same with figures and letters of reference corresponding with those in the
following explanation thereof.
Fig. 1 in the annexed Drawing is an outside plan view; Fig. 2, a side elevation ;
Fig. 3, a horizontal section through the line A, B, in Fig. 2; and Fig. 4, a vertical
section of a piston made according to my Invention.
In the first place I employ a single block a, a, of cast metal, provided with a
circumferential groove b, b, of the required width and depth to receive the metallic
packing, and without any loose cover or other loose part whatever.
The coil or spring c, c, I make (by preference) of steel, either by means of the
process for which Letters Patent (dated 19th December 1877, No. 4826) were
granted to me, or by any other suitable process.
The packing rings d, d, e, c, I also make of steel, using by preference what is
known as "Bessemer" steel, and they are either slightly bevilled inside or made
with a flange around one edge, as shown at Fig. 4 (or both bevilled and flanged).
These rings are cut, as usual, and in order to prevent their odges from cutting the
inside of the cylinder I round both their edges off. This also forms a recess
(where the edges of the two rings meet) for retaining tallow or other lubricating
material. The block a, a, coiled spring c, c, and two packing rings d, d, and e, e,
having been thus prepared I proceed as follows:-I take one end of the spring ring
or coil c, c, and by opening it out slightly I pass it into the groove b, b, in the
block a, a. I then turn the spring ring or coil c, c, round, so that it gradually
screws or worms itself into the circumferential groove b, b, of the block. I then
take the steel packing rings d, d, and e, e, and by opening them out slightly I spring
them over the top and bottom of the block into the spring ring or coil c, c, in the
groove b, b, and the packing of the piston or pump bucket is complete; and it will
be evident that by these means I obtain a piston or pump bucket efficiently packed
with metallic packing without the use of loose covers, nuts, bolts, or other separate
parts other than the spring ring or coil and the two packing rings. The manufac-
Lure therefore is considerably economized, and the pistons are more durable and
less likely to get out of repair than metallic pistons or pump buckets constructed in
the usual manner with a number of separate parts liable to become loose in working.
1 may here observe that although I prefer to make the spring ring or coil of steel,
as before described, yet spring rings or coils of cast metal may be employed for
pistons of large diameters.
•
Having now described the nature and object of my said Invention, together with
the manner in which the same is to be or may be performed or carried into practical

page_text: effect, I wish it to be understood that I claim as my Invention, the improvements
in the construction of pistons and pump buckets and in packing for the same, sub-
stantially as herein before described and illustrated by the Drawings annexed.
In witness whereof I, the said Alexander Oldham, have hereunto set my hand
and seal, this Eighteenth day of May, in the year of our Lord One thousand
eight hundred and eighty.
ALEXANDER OLDHAM. (L.S.)