Note: Descriptions are shown in the official language in which they were submitted.
1
Pipe coupling
FIELD OF THE INVENTION
[0001] This invention relates to a coupling which is suitable for engaging
the outer
surface of a polymeric pipe.
BACKGROUND TO THE INVENTION
[0002] Couplings and transition fittings of the type having a gripping
member are
known. In general these couplings include a nut, body, gripping member having
a plurality of
inwardly directed barbed projections, as well as a sub-assembly of a
compression sleeve and
resilient gasket ring that is typically permanently attached to the inner end
of the
compression sleeve. The nut and the gripping member include abutting tapered
surfaces. A
pipe end is freely insertable through the sub-assembly and into a socket in
the body of the
coupling. As the nut is tightened it exerts both a radial and longitudinal
force on the grip ring
that in turn longitudinally exerts a force on the sleeve and gasket ring. The
gasket ring
encounters an abutment in a socket in the body, and further tightening of the
nut then
further radially compresses the gripping member so that its inwardly directed
barbed
projections engage the outer surface of a pipe to which the coupling is
attached. There may
also be provided abutment surfaces within the body of the coupling and the nut
that abut
inner and outer surfaces of a flange outstanding from the outer end of the
compression
sleeve.
[0003] One skilled in the art will appreciate that as the nut is tightened,
the tapered
surface of the nut acts upon the tapered surface of the gripping member
causing it to be
both compressed and urged into the body. As the gripping member engages the
pipe it is
also drawn into the assembly.
[0004] Whilst this works well, depending on the fluid that the pipes carry
the gasket
ring has to securely seal between the pipe and body. It is an object of the
present invention
to provide for a modified sleeve with a gasket ring that ensures a secure seal
when the pipe
is used to convey gas or to provide the public with a useful alternative.
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SUMMARY OF THE INVENTION
In a first aspect the invention comprises a pipe coupling comprising:
a body having external threads and axially aligned annular inner surfaces;
a nut having internal threads adjacent an inner end thereof engaging the body
external threads, the nut having an outwardly converging internal circular
surface at its
outer end;
an spacer co-operable with the nut and co-operable with the body upon
tightening
of the nut the spacer at its inner end being of a smaller diameter than at its
outer end
abutting the grip ring;
a resilient 0-ring secured to an inner end of said sleeve;
a deformable gripping member having an axially outwardly converging outer
surface
complementary to said axially outwardly converging internal nut surface, the
gripping
member having an internal surface with barbs extending radially inwardly
therefrom;
such that an end of a pipe is freely insertable through said gripping member,
spacer
and 0-ring into the body, and tightening of said nut over said external
threads causes axial
movement of said spacer, sealing engagement of said 0-ring the said body and
the pipe, and
radially inward deformation of said gripping member such that said barbs clamp
such pipe;
and
wherein the 0-ring diameter is greater than that of the spacer at the points
where it
is secured before tightening of the nut and less than that of the spacer when
the nut has
been tightened.
[0005] It should be noted that any one of the aspects mentioned above may
include
any of the features of any of the other aspects mentioned above and may
include any of the
features of any of the embodiments described below as appropriate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Preferred features, embodiments and variations of the invention may
be
discerned from the following Detailed Description which provides sufficient
information for
those skilled in the art to perform the invention. The Detailed Description is
not to be
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regarded as limiting the scope of the preceding Summary of the Invention in
any way. The
Detailed Description will make reference to a number of drawings as follows.
[0007] The accompanying drawings, which are incorporated in and constitute
a part of
this specification, illustrate an implementation of the invention and,
together with the
description, serve to explain the advantages and principles of the invention.
In the drawings,
[0008] FIG. 1 is a partial cross-sectional view illustrating a coupling
embodying the
present invention; and
[0009] FIG. 2 is an enlarged view of a section of the coupling of Figure 1.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The following detailed description of the invention refers to the
accompanying
drawings. Although the description includes exemplary embodiments, other
embodiments
are possible, and changes may be made to the embodiments described without
departing
from the spirit and scope of the invention. Wherever possible, the same
reference numbers
will be used throughout the drawings and the following description to refer to
the same and
like parts.
[0011] The coupling described has particular application for gas, but may
equally well
be used for other fluids such as water or petroleum.
[0012] Shown in the Figures is a coupling 10 for outer surface engagement
of a
pipe (not shown). The illustrated coupling shows two ends adapted to join or
couple two
pipes. However it may equally include only one end where, for example, the
coupling is used
to act as a stop for a pipe, or a three way connection.
[0013] The coupling 10 includes a longitudinal body 12 having male threads
14, the
threads adapted for use by nut 16 having internal threads 18 that engage the
male
threads 14.
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[0014] Figure 1 illustrates on the left hand side the coupling in a state
when a pipe is to
be inserted into the coupling but not engaged while it shows on the right hand
side the
coupling when a pipe has effectively been fully engaged by the coupling.
[0015] Located within the nut and the body is a grip ring 20 and a spacer
22. The end of
the nut 16 includes an outwardly converging surface 24. As the nut is
tightened onto the
body it causes the grip ring to move laterally into the body and also radially
inwardly. The
grip ring has teeth or barbed projections 26 that bite into or engage a pipe
drawing it
inwardly into the body when the nut is tightened. The grip ring 20 abuts the
spacer 22 also
moving it inwardly into the body. The body 12 includes a shoulder 28
constituting an
abutment surface for the grip ring 20.
[0016] The pipe 12 is typically mounted on a liner 30 so that it is not
compressed when
under the force of the grip ring and abutting flange 32. The nut outwardly
converging
surface 24 engages the tapered surface on the grip ring so that as the nut is
screwed onto
the body it causes the grip ring to be forced radially inward. The reader
should now
appreciate that as the grip ring and pushes it radially inwardly, the barbs
biting into the
pipe and dragging it and the liner further into the body 12 at the same time
pushing the
spacer 22 until it abuts the body. With the nut being further screwed onto the
body the
spacer remains in place but the grip ring is compressed downwardly.
[0017] As illustrated on the LHS of Figure 1, the spacer includes a
downward web 34
with an 0-ring 36 attached at its end the 0-ring extending beyond the diameter
of the
spacer at its joint. The body however also extends downwardly so that when the
nut has
been fully screwed on the 0-ring 36 as illustrated on the RHS of Figure 1 has
been slightly
compressed and pushed downward to create a strong seal between the body and
the pipe
(not shown).
[0018] Thus the reader should understand the present invention. When a pipe
is
inserted into the coupling, initial tightening of the nut will cause the grip
ring to engage the
pipe and draw it in radially together with the spacer causing the grip ring 0-
ring to be
compressed. The spacer and the grip ring will then engage an abutment surface
in the body
at which stage they will stop moving radially. However the nut will compress
the grip ring to
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further engage the pipe through its barbs to lock it into place. A liner
ensures that the pipe
is not deformed during this action.
[0019] If the pipe is not inserted into the body and the nut is screwed
forwardly, the
pipe will not be able to be forced inwardly to the body unless the nut is
screwed back to its
loose state.
[0020] In this embodiment the 0-ring diameter is initially greater than the
end of the
spacer but as it is compressed against the body it is forced downwardly until
its inner
diameter is smaller than that of the spacer.
[0021] Although the invention has been shown and described in what is
conceived to
be the most practical and preferred embodiment, it is recognized that
departures may be
made therefrom within the scope and spirit of the invention, which is not to
be limited to
the details disclosed herein but is to be accorded the full scope of the
claims so as to
embrace any and all equivalent devices and apparatus. It is also to be
understood that
reference to any prior art is not to be taken as an admission that that prior
art is part of the
common general knowledge.
LIST OF COMPONENTS
Coupling 10
Body 12
Male threads 14
Nut 16
Internal threads 18
Grip ring 20
Spacer 22
Converging surface 24
Teeth 26
Shoulder 28
Liner 30
Flange 32
Web 34
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0-ring 36
[0022] In any claims that follow and in the summary of the invention,
except where the
context requires otherwise due to express language or necessary implication,
the word
"comprising" is used in the sense of "including", i.e. the features specified
may be
associated with further features in various embodiments of the invention.
[0023] Further advantages and improvements may very well be made to the
present
invention without deviating from its scope. Although the invention has been
shown and
described in what is conceived to be the most practical and preferred
embodiment, it is
recognized that departures may be made therefrom within the scope of the
invention,
which is not to be limited to the details disclosed herein but is to be
accorded the full scope
of the claims so as to embrace any and all equivalent devices and apparatus.
Any discussion
of the prior art throughout the specification should in no way be considered
as an admission
that such prior art is widely known or forms part of the common general
knowledge in this
field.
[0024] In the present specification and claims (if any), the word
"comprising" and its
derivatives including "comprises" and "comprise" include each of the stated
integers but
does not exclude the inclusion of one or more further integers.
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