Improvement in Pistons.
Year: 1890

page_text: Date of Application, 18th Sept., 1890
Complete Specification Left, 17th June, 1891-Accepted, 18th July, 1891
PROVISIONAL SPECIFICATION.
Improvement in Pistons.
We, JOHN COOPER, Pattern Maker, of 72, Nottingham Street, Sheffield, and
THOMAS PATTINSON, Engineer, of Love Street, Sheffield, in the County of York,
do hereby declare the nature of this invention to be as follows:-
Our invention relates to pistons for steam and similar engines and consists in an
improved construction of springs for forcing the piston rings outwards and against
the junkrings or ends of the piston.
One frequently used kind of piston spring consists of a helical spring coiled
circularly or elliptically and bent round inside the piston rings so that its ends meet
and pressing against the inclined surfaces of tapered flanges on the piston rings,
which are thereby pressed against the junkrings or ends and also outwards. It has
been found that in course of time these springs wear grooves into the inclined
surfaces of the rings, which in that case will no longer be forced against the ends so
effectually as when new, and also that the springs themselves become worn thin at
the points of contact with the rings and lose their strength. The object of our
invention is to remedy this defect, which we attain by giving to the springs such a
form that they bear against the inclined surfaces on their entire width or nearly so.
In carrying our invention into effect, we first coil the spring wire or rod helically
and then press the coil so as to be flat on one side and have two adjoining flat sides
at the same angles to the former as are formed by the inclined flanges of the rings
with the cylindrical parts of the same and make the said flat sides of such dimensions,
that when the coil thus formed is bent round inside the piston rings it will bear
against the inclined surfaces of the flanges over nearly their entire width without
touching the cylindrical part, and thus force the rings outwards and endways. The
wearing of grooves into the flanges is thereby prevented, while the spring has a
large bearing surface against the flanges and will not be worn thin or through like
circularly or elliptically coiled springs.
Dated this 17th day of September 1890.
.:
W. T. EMMOTT,
Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvement in Pistons.
We, JOHN COOPER, Pattern Maker, of 72 Nottingham Street, Sheffield, and
THOMAS PATTINSON, Engineer, of Love Street, Sheffield in the County of York,
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 :-
Our invention relates to pistons for steam engines, air pumps, compressors, gas
and similar engines and piston valves, and consists in an improved construction of
springs for forcing the piston rings outwards and against the junkrings or ends
of the piston.
One frequently used kind of piston spring consists of a helical spring coiled
circularly or elliptically and bent round inside the piston rings so that its ends meet,
which spring presses against the inclined surfaces of tapered or conical flanges on
the piston rings and thereby forces said rings against the junkrings or ends and also
outwards. It has been found that in course of time these springs wear grooves into
the inclined surfaces of the rings, which in that case will no longer be forced
D

page_text: outwards against the ends so effectually as when new and also that the springs
themselves become worn thin at the points of contact with the rings and lose their
strength. The object of our invention is to remedy this defect, which we attain by
giving to the springs such a form that they bear against the inclined surfaces on
their entire width or nearly so.
On the sheet of drawings appended hereunto Figure 1 shows a half vertical section
and Figure 2 a half plan partly in section of a piston fitted with our improved spring;
Figures 3, 4 and 5 show radial sections of the coiled spring in three modifications.
In carrying out our invention we first coil the spring wire or rod helically round
a mandril having approximately the form the coils are to obtain and then press the
coil to the required form so as to have two flat sides a a¹ inclined towards each other
at the same angle at which the inclined or conical surfaces bb₁ of the flanges of the
piston rings e and c¹ are inclined toward each other. The inner side d of the coil
is preferably made convex, and the outer side e may be flat or straight as. shewn by
Figure 3, or slightly convex as shewn by Figure 4, or slightly concave as shewn by
Figure 5. We make the flat sides a and a¹ of such length that when the coil thus
formed is bent round inside the piston rings, they will bear against the inclined or
conical surfaces of the flanges over nearly their entire width without touching the
cylindrical part of the piston rings c and e' and thus force the rings, outwards and
endways against the junkring f and piston end
9. The wearing of grooves in the
flanges and is prevented by this improved arrangement or form of spring, while
the spring has a large bearing surface against the flanges of the piston rings and will
not be worn thin or through like circularly or elliptically coiled springs. The
spring is also held more securely in its position and the coil cannot turn partly round
as occurs at times with oval coils.
The improved form of coil is applicable to piston springs formed of a single wire
or rod as well as to those formed of two or more wires coiled together.
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 :
Firstly, in a piston the combination of piston rings having tapering or conical
flanges with a helically coiled spring with coils having two flat sides inclined towards
each other at the same angle at which the inclined or conical surfaces of the said
flanges are inclined towards each other, substantially as hereinbefore described and
illustrated and for the purposes set forth.
Secondly, in pistons the employment of helically coiled piston springs formed with
two flat sides to each coil so arranged that they bear against tapered or conical
flanges of the piston rings over nearly their entire width; for expanding said piston
rings and pressing them against the junkring and piston end, substantially as
herein before described and illustrated.
Thirdly, the formation of helically coiled piston springs with two flat surfaces
inclined towards each other, substantially as hereinbefore described and illustrated
and for the purposes set forth.
Daind this 16th 1.. f T1001
W. T. EMMOTT,
Agent for the Applicants.