Note: Descriptions are shown in the official language in which they were submitted.
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"lMPROVEMENTS RELATlNG TO A HOSE COUPLlNG"
This invention relates to a fitting intended
to provide a sealing connection between a tube and
the fitting.
5. This can variously be described as a hose
coupling or a fitting.
The problem to which this invention is directed
is to provide a fitting of this type which can provide
both a liquid seal and means for holding the tube within
10. the fitting where the fitting as a whole is an integral
moulding.
The invention can accordingly be said to reside
in a fitting facilitating a sealing connection with
a tube to provide a liquid seal, the fitting having
15- an aperture to receive a tube therein, the fitting
being comprised of a plastics material and having
a circumferentially continuous inwardly extending
lip integral with the housing of the fitting~ the
lip being attached to the housing by a portion of
20. reduced thickness and adapted thereby and by the
position of such reduced thickness portion, to be
pivotal about such portion of reduced thickness.
In preference the lip has an innermost face
which is of continuous constant shape.
25. In preference the fitting is integrally formed
of a plastics material of a type such that the portion
of reduced thickness will provide a pivotal effect
for the inner portion of the lip while being sufficiently
stiff to substantially resist deformation about any
30. axis radially aligned with respect to ~he fitting,
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while being able to expand and contract circumferentially.
By having the lip having a cross-sectional shape
of a wedge, provides for this feature of being able
to resist buckling deformation, while at the same
time being able to expand and contract circumferentially
in concert with pivotal action about the portion
of reduced thickness.
In order to limit the extent to which the
pivotal action can extend, there are provided a plurality
10. of segmented tails secured to the lip.
By appropriate selection of the shape of the
lip, the location and shape of the tails, and these
in conjunction both with the plastics type and the
shape and type of tube to be secured, it has been
15~ found that a very excellent fitting being a one off
integral mould, can be provided which can provide
both an effective liquid seal as well as strong mechanical
engagement especially when there is internal liquid
pressure which can have the effect of causing the
20. lip to engage more strongly the external surface
of the gripped tube.
Significant savings are made because there
is no subsequent assembly necessary, for instance,
a sealing ring or a tightening ring as has hitherto
25. been necessary. Furthermore, in use, the tube needs
only to be inserted into the fitting to be secured
thereto. This can provide significant savings in
respect of the time taken to install an irrigation
system.
30~ For a better understanding of the invention
it will now be described with respect to the preferred
embodiment which shall be described with the assistance
of drawings in which :-
3.
FIG. 1 is an end view of a fitting according
to the embodiment;
FI~. 2 is a cross-sectional view along lines
2-2 of Fig. l;
5. FIG. 3 is the same view of the fitting as
in Fig. 2 incorporating9 howeverg an
approaching tube;
FIG. 4 is a detail from Fig. 3 showing the
arrangement upon further en~ry of the
10. tube; and
FIG. 5 is the same detail as in Fig. 4 showing
the arrangement upon an expected attempt
to withdraw the tube and when under
liquid pressure.
15. Referring in detail to the drawings, a
lip 1 is shown as a peripheral portion within the fitting
2 having an innermost sharp corner at 3 which is
of lesser diameter than an outermost corner at 4
The shape of the lip 1 is continuous and consis~ent
20. around the annular path and provides there a continuous
inner face defining a frustro-conical area at 5.
. The fitting 2 is intended for a tube of circular
cross-section and accordingly has itself a circular
cross-section having a central axis at 6.
25. The lip 1 has an inner face at 7 inclined
at 18 to the axis 6. The sides of the lip 1 at
8 and 9 are inclined at 75 to the axis 6
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There is a portion of reduced thickness at
~0 which thereby connects the lip 1 to the
housing 2, the thickness of which is selected together
with the shape of the lip, and the selection of plastics
5. material, so that when an appropriate tube is inserted,
the sharp corner 3 will be caused under compression
to expand and rotate inwards and allow for the entry of
the tube without excessive resistance, also without undue
buckling.
10. The buckling can be said to be deformation
about an axis orientated radially with respect to
the central axis 6 of the fitting 2.
Accordingly by providing the so-called triangular
or wedge shape in cross-section of the lip 1, there
15. is provided this inner stiffness while having this
connected to a portion of the housing through a portion
of significantly reduced thickness at 10, allo~ls
adequate pivotal freedom.
It will be very clear that the characteristics
20. of both the plastics material, the thickness, the
respective angles and the shape of each part, all
go toward making this fitting work for a selected
tube.
It is a feature as shown in the drawings that
25. the fitting is integrally moulded from plastics material
and according to this embodiment this is selected
from a plastics material having an elongation at
break of at least 200%.
Such a material is a polyester sold commercially
under the trade mark "Valox 325" which has an elongation
at break of 300% as well as good tensile and compressive
stren~th and low creep.
5.
Such a material is appropriate f~r manufacturing
a fitting according to this invention where a tube
circular cross-section is made from linear low density
polythene.
5. ln order to ensure that the lip 1 with the
entry of a tube does not ensnare and go past a preferred
position, there are provided a plurality of tails
11 which are separated by slots 12 each of the tails
being integrally secured to and forming part of the
10. lip 1, but the segmentation allows the relative movement
both compression and expansion of the lip 1, together with
the pivoting about the portion of reduced thickness at 10,
to occur without undue restriction.
The effect of each of the tails is therefore
15. in the one instance to limit, with entry of a tube
13 the extent of forward pivoting of the lip 1 as
is shown in Fig. 4, and in the instance of attempted
removal of the tube 13, as shown in Fig. 5, the tail
can eventually engage against portion 14 of the fitting
20. 1, the shape and position of which is selected so
that the sharp corner 3 will not have past further
toward an entry into the fitting 1 than the pivot
axis nominally shown at lS about which it pivots.
It will now be seen from the description of
25. the preferred embodiment that by provision of a lip
portion which is integrally attached to the housing
but is sufficien~ly stiffened to resist deformation
but nonetheless because of the selection of plastic
and the shape will be able to expand and contract
30. modestly, while, however, allowing pivotal freedom
about the portion of reduced thickness, allows for
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pivotal freedom providlng a very effective sealing
and gripping effect when required.
The remainder of the fiLting 2 includes internal
thread portion 16 and protrusions 17 by which the
5. fitting 2 can be held against rotational action to
secure a further fitting in the threaded portion.
Such additional features, however, are entirely
optional.
In respect of each tail 11, the inner surface
10. 18 is aligned to be 1 less flared than the inner
surface 7 of the lip 1.
- The angular relationships are otherwise as
shown in the drawings in respect of the preferred
embodiment, which is shown approximately twice full-size
15. for a conventional fitting.
The naturally existing position as shown in
Figs. 1, 2 and 3 shows that the innermost face of
the lip 1 is shaped and positioned so as to provide
an inwardly tapering shape when without a tube therein
20. as in Figso 4 or 5.
It is noted that the frustro-conical shape
5 defined by the inner face of the lip 1 can according
to ~ broader concept define an angle which is within
the range of 28 to 46.
25. ln the preferred embodiment this is 36.
