AN IMPROVED SPRING PISTON
Year: 1877

page_text: LETTERS PATENT to William Lockwood, of Sheffield, in the County of York,
Engineer, for the Invention of "AN IMPROVED SPRING PISTON."
PROVISIONAL SPECIFICATION left by the said William Lockwood at the
Office of the Commissioners of Patents on the 13th August 1877.
WILLIAM LOCKWOOD, of Sheffield, in the County of York, Engineer.
IMPROVED SPRING PISTON."
"AN
This Invention relates to an improved construction of compound double-action
spring pistons, and is designed to render such pistons especially suitable for steam,
air, and other engines, and pumps and other apparatus or appliances in which a
perfectly tight piston is required.
The improved piston is simple in its construction, and will be found more efficient
in action than any pistons heretofore in use.
The principal feature of the Invention consists in the construction and utilization
of a peculiarly formed spring for distending the piston rings.
The improved spring may be made of steel or other suitable metal or material,'
and of a round, square, oval, or other convenient section. It is coiled in such a form
as to present in one view a series of contiguous horse-shoes or semicircles, and in an
end view at right angles thereto a single such figure. As thus formed the spring is
bent to à circular shape, with the rounded part of the series of horse-shoes outwards,
and its ends are secured and kept. in position by means of a washer having pro-
jecting pins which fit into eyes in the ends of the spring, or by other suitable means.
The diameter of the spring thus bent may be increased or lessened, and its pressure
against the piston rings adjusted as required by uniting the spring ends by a washer
of greater or lesser diameter, or by the use of an adjusting nut on one of the pro-
jecting pins. The spring thus prepared is laid within the recess formed by the
metallic piston rings, and the bends of the series of horse-shoes press alternately
against the upper and lower of such rings in such a manner as to exert a side pres-
Prine 21

page_text: sure against the flanges of the rings which bear against the piston bottom and cover,
and keep them well up thereto, and an outward pressure around the circumference,
tending to increase the diameter of the rings, by this means ensuring a perfectly
steam, air, or other vapor or fluid-tight piston.
For small pistons I employ a modified form of the above-described spring, and I
make it out of ribbon, or thin flat steel, or other suitable metal or material, first
perforating it at equal distances with holes, and then bending or corrugating it (by
any suitable means) in such a manner as that every alternate bend is perforated
and the others solid, and then bend it to a circular shape with the perforated cor-
rugations outwards. The action of this spring is precisely similar to that above
described. The ends of this spring may be connected by means of a pin rivetted
on to one end of the spring, and projecting into a hole in the other end."
In the outer face of each piston ring I form a continuous shallow cavity to reduce
the friction of the piston.
Suitable cavities are cast in the body of the piston to receive the nuts by which
the bolts securing the cover to the piston are secured.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Lockwood in the Great Seal Patent Office on the 13th
February 1878.
WILLIAM LOCKWOOD, of Sheffield, in the County of York, Engineer.
IMPROVED SPRING PISTON."
" AN
This Invention relates to an improved construction of compound double-action
spring pistons, and is designed to render such pistons especially suitable for steam,
air, or other engines and pumps, and other apparatus in which a perfectly tight
piston is required.
The improved piston is simple in its construction and will be found more efficient
in action than any pistons heretofore in use.
It is illustrated on the accompanying Sheet of Drawings in Figures 1 to 5, of
which Figure 1 represents a plan view, one half of the cover being removed to show
the peculiar conformation of the spring; Figure 2 is a sectional elevation thereof
through the line A, B, C; Figure 3 is a plan view of a modified form of spring, and
Figure 4 an elevation thereof; and Figure 5 is a plan view of the "gluts" I, let into
the piston rings to cover the joints thereof.
The principal feature of the Invention consists in the construction and utilization
of a peculiarly formed spring 1 for distending the piston rings 2, and which may be
made of steel or other suitable metal or material of a round, square, oval, or other
convenient section. The spring is formed by being coiled in such a manner as to
present in one view a series of contiguous horse-shoes or semicircles (see Figure 1),
and in end view at right angles thereto a single such figure (see Figure 2). As thus
formed the spring is bent to a circular shape, with the rounded parts of the series
of horse-shoes outwards, as shown in Figure 1, and its ends 4 are secured and kept
in position by means of a washer 5, having projecting pins 6, which fit into eyes 7 in
the ends 4, or by other suitable means. The diameter of the spring thus bent may
be increased or lessened and its pressure against the piston rings 2 adjusted as
required by uniting the spring ends 4 by a washer 5 of greater or less thickness, or

page_text: by the use of an adjusting nut on one of the pins G. The spring thus prepared is
laid within the recess 8 formed by the rings 2, and the bends 3 of the series of horse-
shoes press alternately against the upper and lower of such rings in such a manner
as to exert a side pressure against the flanges 9 of the rings, which bear against the
piston bottom 10 and cover 11, and keep them well up thereto, and a direct outward
pressure around the circumference tending to increase the diameter of the rings, by
this means ensuring a perfectly steam, air, or other vapor or fluid-tight piston.
For small pistons I employ a spring 12 of the modified form, illustrated in Figures 3
and 4, and this spring I make of ribbon or thin flat steel or other suitable metal or
material, first perforating it at equal distances with holes 13, and then bending or
corrugating it (by any suitable means) in such a manner as that every alternate bend
is perforated and the others solid, and then bending it to a circular shape with the per-
forated corrugations outwards, as shown. The ends of this spring may be connected
by means of a pin 14 rivetted on to one end of the spring and projecting into a hole
in the other end. The action of this spring is precisely similar to that above
described.
I would here remark that these improved springs are also applicable to pump
buckets and to other similar apparatus, in which they can be conveniently used.
In the outer face of each piston ring 2 I form a continuous shallow cavity 15 to
reduce the friction of the piston to a minimum. I also cast suitable cavities 16 in
the body of the piston to receive the nuts 17, by which the bolts 18 securing the
cover 11 to the piston body 10 are secured. 19 represents the piston rod, and 20
the cotter for securing the rod to the piston body.
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
effect, I would remark in conclusion that I claim as my Invention,―
The above-described improvements in the construction of compound double-action
spring pistons, substantially as described, and as illustrated on the accompanying
Sheet of Drawings.
And I also claim the peculiar construction or formation of the above-described
improved springs, substantially as described, and as illustrated on the accompanying
Sheet of Drawings, and the utilization thereof in or for the purposes herein-before
referred to.
In witness whereof, I, the said William Lockwood, have hereunto set my
hand and seal, this Eighth day of February, in the year of our Lord One
thousand eight hundred and seventy-eight.