Improvements in Metallic Packings for Piston Rods and other Rods Requiring Packing.
Year: 1886

page_text: Date of Application, 3rd Dec., 1886.
Complete Left, 1st Sept., 1887
Complete Accepted, 4th Oct., 1887.
PROVISIONAL SPECIFICATION.
Improvements in Metallic Packings for Piston Rods and other
Rods Requiring Packing.
We ROBERT MARSHALL and GEORGE HERBERT ADAIR THUNDER both of 121
Fenchurch Street in the City of London, Engineers do hereby declare the nature of
this invention to be as follows:-
We have observed that when the piston rod of a cylinder working with fluid pressure
does not move to and fro accurately in one and the same axial line, but deviates
laterally to a greater or less extent from that course, causing the piston rod to leave
the packing on the one side or the other, the steam or other fluid under pressure will
penetrate between the packing and the rod and will force the packing still farther away
from the rod. When the packing consists of two or more metallic rings, the ring
nearest the neck bush of the cylinder being first subject to the above described action,
will allow the fluid pressure to penetrate to the other packing rings and to press these
with full force against the rod, thereby causing the rings to wear away rapidly, and
producing increased friction; and as the rings will cling to the rod on account of the
pressure at the back, it also follows that they will move to and fro somewhat with the
same, causing the last ring to leave its scat on the end of the stuffing box, so that
the fluid pressure can then easily escape by the gland.
Our invention has for its object to prevent this detrimental action in packing
consisting of divided metallic packing rings that are pressed against the piston or
other rod by spring or other action, and it consists in providing means whereby the
two or more parts of the packing ring are tied together in such manner that while they
are free to be pressed inwards against the rod by the spring or other action, they are
prevented from being forced outwards beyond the limit allowed by such tying device.
This arrangement may be applied to all the rings of the packing but we prefer to
apply it only to the ring with which the fluid pressure first comes in contact.
Various arrangements may be employed for carrying our above described invention
into practice.
Thus according to one arrangement, suitable for large packing rings, we form
a groove in the outer periphery of the divided ring into which we fit a metal band

page_text: that is slightly less in length than the circumference of the ring, and we pass a wiro
loop through holes in the two ends of the band, so that by twisting up the wire, the
band may be tightened round the packing ring to any extent desired. Or the two
ends of the band may be made to overlap, one end being provided with a slotted hole,
so that a set screw passing through such hole and through a hole in the other
end and screwing into a hole in the packing ring, is made to nip the band and thus
hold it in position after it has been strained tightly round the packing ring. The one
end of the band may then be bent back over the head of the set screw so as to prevent
this from unscrewing.
For smaller packing rings, the metal band may be replaced by a copper wire passed
round the ring and twisted together.
According to another arrangement we form holes through the one part of the ring
in a direction parallel with the flat faces thereof and at right angles to the joint,
through which holes we pass screws that screw into corresponding holes of the joint-
face of the other part, so that by screwing up these screws the parts of the ring are
tightened together, the holes in the one part through which the screws pass being
however made with sufficient play to allow of the parts being drawn together freely
by the spring action as the ring wears.
According to another arrangement a small thin metal plate with slotted holes may
be placed over cach joint, with set screws passing through the holes and screwing into
the two parts of the ring, so as to nip the plates firmly when the parts have been
pressed tightly against the rod.
In all the above described arrangements it will be seen that the tying arrangement
can be tightened up from time to time as the packing wears.
Dated this 3rd day of December 1886.
ABEL & IMRAY,
Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in Metallic Packings for Piston Rods and other
Rods Requiring Packing.
We, ROBERT MARSHALL and GEORGE HERBERT ADAIR THUNDER both of 121
Fenchurch Street in the City of London, Engineers 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 :-
:-
We have observed that when the piston rod of a cylinder working with fluid
pressure does not move to and fro accurately in one and the same axial line, but
deviates laterally to a greater or less extent from that course, causing the piston rod to
leave the packing on the one side or the other the steam or other fluid under pressure
will penetrate between the packing and the rod and will force the packing still farther
away from the rod.
When the packing consists of two or more metallic rings, the
ring nearest the neck bush of the cylinder being first subject to the above described
action, will allow the fluid pressure to penetrate to the other packing rings and to
press these with full force against the rod, thereby causing the rings to wear away
rapidly and producing increased friction; and as the rings will cling to the rod on
account of the pressure at the back also follows that they will move to and fro
somewhat with the same causing the last ring to leave its seat on the end of the
stuffing box, so that the fluid pressure can then easily escape by the gland.
Our invention has for its object to prevent this detrimental action in packing
consisting of divided metallic packing rings that are pressed against the piston or
other rod by spring or other action, and it consists in providing means whereby the
two or more parts of the packing ring are tied together in such manner that while
they are free to be pressed inwards against the rod by the spring or other action they
are prevented from being forced outwards beyond the limit allowed by such tying
device.
This arrangement may be applied to all the rings of the packing but we prefer to
apply it only to the ring with which the fluid pressure first comes in contact.
Various arrangements may be employed for carrying our above described invention
into practice.
Thus according to one arrangement suitable for large packing rings we form a
groove in the outer periphery of the divided ring into which we fit a metal band that
is slightly less in length than the circumference of the ring, and we pass a wire loop
through holes in the two ends of the band so that by twisting up the wire, the band
may be tightened round the packing ring to any extent desired. Or the two ends of
the band may be made to overlap, one end being provided with a slotted hole so that
a set screw passing through such hole and through a hole in the other end and
screwing into a hole in the packing ring, is made to nip the band and thus hold it in
position after it has been strained tightly round the packing ring. The one end of
the band may then be bent back over the head of the set screw so as to prevent this
from unscrewing.

page_text: For smaller packing rings the metal band may be replaced by a copper wire passed
round the ring and twisted together.
According to another arrangement we form holes through the one part of the ring
in a direction parallel with the flat faces thereof and at right angles to the joint
through which holes we pass screws that screw into corresponding holes of the joint-
face of the other part so that by screwing up these screws the parts of the ring are
tightened together the holes in the one part through which the screws pass being how-
ever made with sufficient play to allow of the parts being drawn together freely by
the spring action as the ring wears.
According to another arrangement a small thin metal plate with slotted holes may
be placed over each joint with set screws passing through the holes and screwing into
the two parts of the ring so as to nip the plates firmly when the parts have been pressed
tightly against the rod."
In all the above described arrangements it will be seen that the tying arrangement
can he tightened up from time to time as the packing wears.
The accompanying drawing shews one arrangement of our above described invention.
Fig. 1 shews a divided packing ring with the means for tying the parts together.
Fig. 2 shews the packing ring without the tying band and Fig. 3 shews a plan of the
tying band. In this arrangement the parts of the packing ring are held together by
means of a metal ring A which fits into a groove C in the parts of the packing ring
and is tightened up by having its ends formed with right and left screw threads which
screw into a socket B so that by turning this the ends are drawn together to the
desired extent.
Having now particularly described and ascertained the nature of this invention and
in what manner the same is to be performed we declare that what we claim is :-
The use in combination with divided metallic packing rings that are pressed against
the piston or other rod by spring pressure, of means whereby the parts of the ring
are held together so that they cannot separate beyond a certain degree, while such
means allow the parts perfect freedom to be pressed against the rod by the spring
action substantially as herein described.
Dated thin 1at day of Santambas 1007
ABEL & IMRAY,
Agents for the Applicants.