Improvements in or relating to the Construction of Pistons and their Packings.
Year: 1894

page_text: Date of Application, 14th June, 1894-Accepted, 18th Aug., 1894
COMPLETE SPECIFICATION.
Improvements in or relating to the Construction of Pistons and
their Packings.
•
I REGINALD HADDAN of the Firm of Herbert Haddan and Co. of
18 Buckingham Street, Strand, W.C. London, Patent Agent, do hereby declare
the nature of this invention, a communication to me from abroad by François
Pons y Curet of Barcelona in the Kingdom of Spain, and in what manner the
same is to be performed to be particularly described and ascertained in and
by the following statement :-
The improved construction which forms the object of this invention is intended
to produce a more efficient hermetical closure between the two chambers, into
which the inner space of a cylinder is divided by the piston which moves therein.
It possesses moreover the advantage of considerably diminishing the friction and
consequently the necessary lubrication of the cylinder; furthermore of being very
simple and solid and of assuring the preservation of the packing-ring as well as
of the inner surface of the cylinder.
The pressure of the packing ring upon the inner surface of the cylinder is
uniformly distributed so that the wear of the ring and of the cylinder takes place
in a uniform manner, oval wearing of the cylinder being avoided. This system
may be applied to steam engines as well as to piston pumps and to gas and
petroleum motors and in general to all mechanism comprising a piston moving
in & cylinder.
This construction is represented in the annexed drawing in which
Fig. 1 is a view of a piston in which this improved system is used, the left hand
part being shown in section.
Fig. 2 is a sectional plan of the same piston in a plane parallel with the face of
the piston.
Figs. 3, 4, 5 and 6 are detail views of parts of the construction and are explained
hereinafter.
This piston is composed of a body A B in one piece, generally made of soft
cast iron or mild steel and is connected by screw threads with the piston rod C D,
which latter may be prolonged at both sides of the piston in order to be supported
and guided in stuffing boxes by the two extremities of the cylinder so that oval
wear of the cylinder is avoided.
The body of the piston is hollowed out cylindrically at E, F, G, H, and this
hollow is made in the cast metal and extends to each side of the partition I, L,
which forms a disc made in one piece with the body and united with, and extending
outward froin, the central core of said body.
In the interior of the hollow E, F, G, H, the following parts are placed
1. Two flat spiral springs formed of narrow steel band, one in each com-
partment, that is to say on each side of the partition I, L. Each spring T
and T¹ is united by one of its extremities with the massive part or core M of the
body by any suitable means, say for instance by introducing the extremity R
or R' of the spring bent to an angle into a narrow mortise, made in said core M.
The two other extremities of the springs remain free.
These
2. Three segments S, S', S", upon the under edges of which acts one of the
springs T, and three other segmental pieces V, V and V having wedge like
projections, 1, 2, 3, 4, and upon which pieces the other spring T¹ acts.
springs so act upon the said parts as to have the tendency to displace them
radially from the core of the body.

page_text: One of the segments S is represented in Fig. 3, Fig. 4 is a section on the
line Y Y' of Fig. 3, which shows the exact form of said segment.
One of the pieces V is represented in Fig. 5 and its exact form is shown in
Fig. 6 in section on the line Z, Z1, of Fig. 5.
When mounted in the body of the piston the segments S and the pieces V are
arranged in such a manner that the inclined plane surfaces 1-2 and 3-4 of the
pieces V are in respective contact with the plane inclined surfaces 5-6 or 7-8
of the two adjoining segments S, so as to form an hermetic joint. This method
of mounting is indicated in Fig. 2 and in the sectional part of Fig 1.
The thinner parts 0, 01 and P, P1 (Figs. 4 and 6) rest one above the
partition I, L and the other beneath the same. The whole of these pieces
constitutes within the piston a packing ring which, under the action of the
springs T, T is distended radially from the core M.
3. In the body there are also arranged bolts or pins Q (Fig. 1) which are
symmetrically distributed as seen from Fig. and which pass through the two
plates A B of said body and through small sleeves Q1 arranged inside of the body
and press the whole forcibly together in order to maintain the parallelism of the
walls K, K and K', K', of the said body.
As may be judged from this arrangement, the spiral springs previously
compressed during the mounting, act upon their respective segments S and wedge
segments V in proportion as the outer cylindrical surface of such segments S
which constitutes the packing ring of the piston wears, and this assures the
hermetic closure between the piston and the cylinder, so that there is only
necessary to mount in each piston one ring of a breadth proportionate to the
diameter of the piston. Owing to this fact the friction is greatly diminished and
a considerable economy results therefrom in the useful effect of the machine and
the lubricating of the cylinder and piston.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be described, I declare that what I
claim is.
1. A piston having an annular space containing one or more spiral springs,
whose spirals are substantially concentric with the axis of the piston and one or
more annular sets of segments distended by said spiral springs adapted if desired
to overlap by inclined planes for the purpose set forth.
2. The construction of piston body with segmental packing ring and spiral
spring or springs substantially as set forth.
100
R. HADDAN.