Improvements in and connected with Packing-rings for Pistons.
Year: 1889

page_text: Date of Application, 2nd Nov., 1889-Accepted, 7th Dec., 1889
COMPLETE SPECIFICATION.
Improvements in and connected with Packing-rings for Pistons.
We, WILLIAM JOWETT of Dove Bank Mills Mellor near Marple Bridge in the
County of Derby, Wadding Manufacturer, and GEORGE SPENCER of 66 Bennett Street,
Newton, Hyde, in the County of Chester, Mechanical Engineer, do hereby declare the
nature of this invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement. :-
This Invention relates to packing rings for pistons and it has for its object to enable
the ring to be removed from the piston with facility and to be replaced thereon when
required without entirely removing the piston from the cylinder.
In carrying out our Invention we form a spiral groove in the piston block in such
a manner that the groove runs out at one or both ends or it may be stopped at one
end and run out at the other. In the spiral groove so formed we insert a spiral ring
having a slightly larger diameter than the piston block. In the open end or in each
of the open ends of the spiral groove we insert a screw plug or stop to retain the ring
upon the block.
We will proceed to more particularly describe our Invention with reference to the
accompanying drawings in which Fig. 1 represents the piston with the packing ring
thereon; Fig. 2 the piston block with the spiral groove thereon for the reception of
the packing ring; and Fig. 3 the spiral packing ring.
In the drawings a comparatively small piston is shewn and it will be understood
that the pitch of the groove and ring will vary according to the diameter of the piston
but that in all cases we prefer to make more than two and preferably three or four
complete turns in the spiral ring A. In the drawings the ring is represented as
having three and a half turns and this will generally be found a convenient number
in ordinary practice.
As shewn in the drawings the spiral groove runs out at one end B where a screw
plug C is inserted in the groove. The other end of the groove is stopped in the body
of the piston block or it may run out and be similarly closed by a screw plug.
The ring A and the groove D have respectively such forms and dimensions that the
ring is an easy fit in the groove and that the outside diameter of the ring is some-
what larger than the outside diameter of the block. Both the rings and the groove
have preferably rectangular cross sections as indicated in the drawings.
The screw plug C must be inserted in the groove at such a distance from the end
of the ring when it is in the groove as to allow for the greater length occupied by the
ring in the groove when the ring is compressed by the walls of the cylinder.
To place the ring upon the block the screw plug is removed and one end of the
ring being inserted in the end of the groove the ring is turned until it has screwed
itself entirely into the groove when the screw plug may be replaced. The ring is
removable by a reversal of the operation.
We are fully aware that spiral packing rings for pistons have been used for many
years both fitting into a groove and into an annular recess in the piston, and we
therefore desire it to be understood that we do not make any claim for the spiral
ring or for a spiral seating for the ring but only for the means and devices for
enabling the ring to be readily removed from or placed upon the piston as hereinafter
set forth.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is;-
(1) In a piston having a spiral packing ring in a spiral groove; forming the groove
in such a manner that it

page_text: of the piston at the other end, the unstopped end of the groove being fitted with a
removable plug or stop; substantially as and for the purpose hereinbefore described
and as illustrated by the accompanying drawings.
(2) In a piston having a spiral packing ring in a spiral groove, forming the groove
in such a manner that the groove runs out at both ends and is closed at each end by
a removable plug or stop; substantially as and for the purpose hereinbefore described|
and as illustrated by the accompanying drawings.
Dated this 30th day of October A.D. 1889.
WILLIAM E. HEYS,
Agent for the Applicants.