Improvements in the Construction of Packing Rings for Pistons and the like.
Year: 1898

page_text: Date of Application, 12th Sept., 1898-Accepted, 22nd Oct., 1898
COMPLETE SPECIFICATION.
Improvements in the Construction of Packing Rings for Pistons and
the like.
I, EMILE CAPITAINE, of Frankfort on Main, Germany, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
This invention relates to improvements in the construction of packing rings
for pistons, piston-rods and the like. Hitherto the necessary tension has been
given to these packing rings for pistons, piston rods and plunger pistons by first
making the ring thicker at the point (Fig. 3 of the accompanying drawing),
then cutting out a piece (Fig. 4) and thereupon pressing it together (Fig. 5)
whereby the ring assumed a form which was not circular. In this compressed
condition the ring was forced into a cylinder or chuck (Fig. 6) and rough turned
inside and outside or turned to the required dimensions at once, then more or less
uniformly compressed inside (or outside) by hammering or rolling and subse-
quently cut open or the ring was simply "round cornered" (rounded off) by
tension, or finally it was driven open by means of springs placed within or by
wedges inserted between the ends of the rings. The rings so produced did not
press uniformly against the cylinder at the several points of contact. In order
to obviate this unequal pressure of the rings against the surface of the cylinder,
the section of the ring was diminished or reduced towards the ends (so called
eccentric rings) (Fig. 7). It is true that rings of this kind can be made to furnish
the desired pressure against the cylinder by being uniformly "hammered over";
nevertheless these, when inserted within the groove of a piston (Figs. 8 and 9)
used for gas-motors, air-pumps etc., are not altogether satisfactory, as they form
too many objectionable spaces (Z Figs. 8 and 9) and moreover the contact surfaces
at a and ¹ (Fig. 8) are unequal; in consequence of which the thin contact surfaces
at a Fig. 8 wear away more than the thicker opposite contact surfaces at ¹ Fig. 8.
According to my invention, the ring having been turned to a suitable diameter
and of like or equal cross-section throughout is compressed in a varying degree
by hammering or rolling on its inner surface (in the case of a ring which is to
have spring action outwards) or on the outer surface (when the spring action is
inwards).
In operation the ring is compressed to a greater degree at the point a lying
opposite to the ends of the ring the strength of which gradually diminishes
towards the ends b, as indicated by the shading in Figs. 1 and 2 of the drawing.
By this means it is possible to produce a ring of uniform thickness of sides or
section capable of pressing uniformly throughout at all points against the contact
surfaces and without any further turning or reduction after the hammering or
rolling has been effected.
The clearance space Z Fig. 10 in opposition to the so-called eccentric rings is
practically uniform all around; no objectionable spaces are formed into which
the heated gas (in the case of gas motors), the air (in the case of air-pumps) or

page_text: the steam (in the case of steam engines) can penetrate and expanding further
carry away the lubricant. Again the contact surfaces y (Fig. 10) are uniform
throughout, so that there is uniform wear of the packing surfaces y.
The object
of this invention as will be seen from the foregoing, is not the complete "hammer-
ing over " of a packing ring but merely the compressing in such a manner as to
produce a ring of equal cross section throughout (that is not turned eccentrically
and of varying thickness) (strength) compressed at the point lying opposite to the
open ends of the same the compression being gradually reduced towards the ends.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is-
In packing rings for pistons and the like, forming the cut ring of equal cross-
section throughout, compressing either interiorly or exteriorly according as it
is wished that the ring should tend to expand or to contract-the ring by hammer-
ing or rolling, the compression being greatest at the point opposite to the ends of
the cut ring and diminishing therefrom gradually towards the ends, substantially
as and for the purposes described.