IMPROVEMENTS IN METALLIC PACKINGS FOR PISTON RODS AND THE LIKE
Year: 1885

page_text: I, HENRY PARKIN of 8 Albert Terrace, Bow, in the County of Middlesex
Engineer, do hereby declare the nature of said invention for "IMPROVEMENTS IN
METALLIC PACKINGS FOR PISTON RODS AND THE LIKE to be as follows:-
My invention relates to an improved construction of metallic packing for use in
stuffing boxes of steam cylinders and for application generally to piston-rods and
the like.
In applying my invention to a steam engine cylinder, the stuffing box is of the
kind commonly employed and consists of a hollow cylindrical chamber formed in
the cylinder cover and having its inner end open for the passage of the piston-rod.
When the latter is in place, the chamber becomes an annular cavity, closed at one
end, open at the other, and surrounding the piston-rod. Into this, cavity my
improved packing is introduced, and is there confined and adjusted by means of a
gland in conjunction with screw-studs or other fastenings.
"
The arrangement of the metallic packing to which my invention more particu-
larly relates, is of the following character. Of brass "Babbett or other suitable
metal I form two split rings of an internal diameter corresponding with that of the
piston-rod. These lining rings are both cylindrical and conical as to corresponding
portions of their outer surfaces. Surrounding the contiguous cylindrical portions
of the said rings is another metallic split ring, the outer surface of which is coned
in opposite directions, the smaller diameters being towards the extremities of the
said ring. Externally to each of the conical portions of this ring and to the
protruding conical extremity of each of the inner or lining rings is fitted a solid
ring, the outer surface of which is cylindrical and approximately corresponds in
diameter with that of the stuffing box, whilst the inner surface of the same has the
same degree of conicity as that possessed by the rings embraced by it. Each of
these solid rings may therefore be regarded as an annular wedge whereof the inner
side is inclined to, and the outer side parallel with, the axis of the piston-rod the
two wedges being so arranged that their thin ends point towards one another.
On the lining rings in contact with the piston-rod becoming reduced in thickness,
owing to wear, the gland is tightened down upon the outer of the two annular
wedges, which sliding endwise and acting in conjunction with the annular wedge
.

page_text: at the opposite or inner end of the packing causes the split ring to be pressed
radially inwards upon the inner or lining rings and these in turn to be forced into
close contact with the surface of the piston rod.
The annular wedges, although acting directly on parts of the inner or lining
rings exert a considerable or the greater portion of their pressure on the same
through the intervening hard metal split ring; whereby the strain exerted by the
adjusting wedges is more equally divided over the whole surface of the lining of
the packing.
I have described the portion of the packing in contact with the rod as disposed
in two rings, the splits therein breaking joint. It is however obvious that the
lining might be subdivided into a larger number of rings if preferred.
I sometimes insert between the gland and the outer of the two annular wedges
above described, a coil of soft packing, with the object of checking the tendency
for a slight leakage of steam to take place before the piston-rod becomes polished
by wear and the metallic lining of the packing arrives in a state of perfect working
order.

page_text: the like.
I, HENRY PARKIN, of 8 Albert Terrace, Bow, in the County of Middlesex,
Engineer, 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 :-
My invention relates to an improved construction of metallic packing for use in
stuffing-boxes of steam-cylinders and for application generally to piston-rods and
the like.
In applying my invention to a steam-engine cylinder, the stuffing-box is of the
kind commonly employed and is represented in the accompanying drawings, of
which Figure 1 is a longitudinal section and Figure 2 a transverse section on
the line YZ. Similar letters of reference indicate corresponding parts in both the
Figures. A is the piston-rod and B the cylinder-cover having a stuffing-box or
hollow cylindrical chamber formed in it, the inner end of which is fitted in the
usual manner with a bush C through which the piston rod passes. When the
latter is in place, an annular cavity D, closed at one end by the bush C and open
at the other, is left for the reception of my improved packing, which is there
confined and adjusted by means of the gland E in conjunction with screw-studs é e
or other fastenings.
The arrangement of my improved packing is as follows: Of brass, "Babbitt,”
or other suitable metal, I form two split rings F F of an internal diameter corre-
sponding with that of the piston-rod A. These lining rings are both cylindrical
and conical as to corresponding portions of their outer surfaces, as shewn.
Surrounding the contiguous cylindrical portions of the rings F F¹ is another split
ring G, the outer surface of which is coned in opposite directions and in continuity
of the conical portions of the rings F F¹. The three split rings F F and G are
held together externally by two solid rings H H' the outer surfaces of which are
cylindrical, whilst their inner surfaces are coned and bear evenly against the three
inner rings aforesaid. The rings H H¹ act, therefore, in opposite directions as
annular wedges. At the same time they, as also the ring G, have freedom in the
stuffing-box; the vacant space in the cavity D being provided to permit of the
whole packing moving laterally as it floats or rides on the piston-rod.
On the lining rings F F1 becoming reduced in thickness, owing to wear, the
gland E is tightened down upon the annular wedge H, which, acting in con-
junction with the annular wedge H at the opposite or inner end of the packing,
causes the split ring G to contract upon the inner or lining rings F F¹ forcing them
into close contact with the surface of the piston-rod A.
The annular wedges H H although acting directly on the coned parts of the
rings FF, exert a considerable or the greater portion of their pressure on the
same through the intervening hard metal split ring G; whereby the strain exerted
by the annular adjusting wedges H H¹ is more equally divided over the whole
surface of the rings F F.

page_text: I have described the portion of the packing in contact with the piston-rod as
disposed in two rings, the splits therein breaking joint. It is, however, obvious
that the lining might be subdivided into a larger number of rings, if preferred.
I have shewn the ring G split in two places instead of one, but this is not essential.
I sometimes insert between the gland E and the annular wedge H a coil of soft
packing, with the object of checking the tendency for a slight leakage of steam to
take pace before the piston-rod A becomes polished by wear and the lining rings
F F¹ arrive in a state of perfect working order.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what
I claim is
For packing piston-rods and the like, the use of two similar annular wedges
effecting the radial contraction of a split ring or portions of a divided ring, the
latter operating in conjunction with the said annular wedges to force an enclosed
lining ring or rings into contact with the rod to be packed, the whole packing
floating on the rod or being capable of lateral movement within the stuffing-box.