IMPROVEMENTS IN PISTONS
Year: 1883

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LETTERS PATENT to John Elliot, John Slight Jeffery and Tom Kerman all of
Cardiff, in the County of Glamorgan Engineers for an Invention of
166 IMPROVEMENTS IN PISTONS
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PROVISIONAL SPECIFICATION left by the said John Elliot, John Slight
Jeffery and. Tom Kerman at the Office of the Commissioners of Patents on
the 6th July 1883.
JOHN ELLIOT, JOHN SLIGHT JEFFERY and TOM KERMAN all of Cardiff in the
County of Glamorgan, Engineers "IMPROVEMENTS IN PISTONS
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According to this invention we place between the body of the piston and the
junk ring or top of the piston two metallic open piston rings which by tongue and
groove or otherwise are so connected as to expand and contract together and to
recede from and approach to each other as required. The opening is partly filled
by the usual tongue piece. The upper ring has an upper flange and the lower
ring a lower flange. In order to produce the required tension for the said piston
rings to fit fluid tight in the cylinder or barrel we provide an inner open steel
tension ring having a helical or other spring or springs inserted between lugs or
flanges formed at each side at the opening, thus tending to force it still more open
or apart and thus exerting a like force on the piston rings. In order furthermore
to produce the required. or desirable pressure of the piston rings against the body
of the piston and against the junk ring respectively we provide the aforesaid
inner tension ring with two or more springs. We find it advantageous to make
each in the form of two bow springs united back to back to a square stud fitting
in a corresponding hole in the tension ring, the said springs having lateral end
projections which lie in corresponding notches formed in the upper and lower edges
of the tension ring. The ends of the said bow springs rest against the aforesaid
flanges of the piston rings.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Elliot, John Slight Jeffery and Tom Kerman in the-
Patent Office on the 5th January 1884.
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JOHN ELLIOT, JOHN SLIGHT JEFFERY and TOM KERMAN all of Cardiff in the
County of Glamorgan, Engineers "IMPROVEMENTS IN PISTONS."
According to this invention we place between the body of the piston and the
junk ring or top of the piston two metallic open piston rings which by tongue and
groove or otherwise are so connected as to expand and contract together circum-
ferentially while free to recede from and approach to each other as required. The
opening is partly filled by the usual tongue piece. The upper ring has an upper
flange, and the lower ring a lower flange. In order to produce the required tension
for the said piston rings to fit fluid tight in the cylinder or barrel, we provide an
inner open steel tension ring having a helical or other spring or springs inserted
between lugs or flanges formed at each side at the opening, thus tending to force
it still more open or apart, and thus exerting a like force on the piston rings. In
order furthermore to produce the required or desirable pressure of the piston rings
'against the body of the piston and against the junk ring respectively we provide
the aforesaid inner tension ring with two or more springs. We find it advan-
tageous to make each in the form of two bow springs united back to back to a
square stud fitting in a corresponding hole in the tension ring, the said springs
having lateral end projections which lie in corresponding notches formed in the
upper and lower edges of the tension ring. The ends of the said bow springs rest
against the aforesaid flanges of the piston rings,
Figure 1 of the accompanying drawing is a vertical part sectional elevation of
a piston constructed or fitted according to this invention. Figure 2 is a plan of
same with junk ring and upper piston ring removed; Figure 3 is plan of a piston
ring; Figure 4 vertical part sectional elevation of the two piston rings, and
Figure 5 is a plan view, and Figure 6 vertical section of the inner tension ring.
A is the body of the piston, and B the junk ring of an ordinary piston such as
may be used for a steam cylinder; C C are two metallic open piston rings, shown
separately at Figures 3 and 4; these are connected by tongue and groove as shown,
or it might be other equivalent means for expanding and contracting. together
while free to approach each other or recede from each other. The opening is
partly filled by the usual tongue piece D. The upper ring C has an upper
flange C¹ and the lower ring C a lower flange C¹. E is an inner steel ring (shown
separately in Figures 5 and 6) which serves to produce the required tension
causing the rings C to open and to fit as tightly as required in the cylinder or
barrel. F is a helical spring mounted on studs E¹ and between lugs or flanges E2
formed on the tension ring E; the spring F tends to open the ring E still more
and thus exert pressure on the inside of the piston rings C. Other suitable form of
spring may be used for this purpose, or the ring. E may itself be made with
sufficient tension to open without any special spring. The ring E is also provided
with two or more springs G, in this case four in number, for the purpose of
exerting a certain pressure against the lower flange of the body A of the piston
and against the underside of the junk ring B. These springs G are by preference
made as shown viz in the form of two bows united back to back to a stud G¹ which
with its square shank fits in the square hole in the tension ring E; the springs G
are shown with lateral end projections which lie in corresponding notches E³ formed
in the upper and lower edges of the tension ring E. The ends of the bow springs G
rest against the flanges C³ of the rings C. .

page_text: And having thus described and ascertained the nature of this our invention and
the mode of carrying the same into effect we declare that we claim :-
The piston rings C in combination with the inner tension ring E for pressing
the rings C against the inside of the cylinder, and with springs for pressing the
rings C apart and against the piston flange and the junk ring or cover substantially
as described and shown.
In witness whereof we the said John Elliot, John Slight Jeffery and Tom
Kerman have hereunto set our hands and seals this Thirty first day of December
in the year of our Lord One thousand eight hundred and eighty three.
TOUN TALLIO