Note: Descriptions are shown in the official language in which they were submitted.
1 320235
This invention relates to a pipe coupling for use in
forming a sealed connection between two conduits. The invention
has particular application in the coupling of hoses to the
radiators of automobiles and this application will be described
as exemplary of many uses for the i~vention.
At present, the coupling of a hose to a radiator is
typically achieved by clamping the end of the hose over a short
tube having a raised bead at its end to enhance the sealing
action. The clamp used to tighten the hose on the tube is
commonly a steel band having a screw device to tighten the band
on the hose.
The hose is normally an interference fit over the tube
and so an operator connecting hoses to radiators on, for
example, an automobile assembly line may experience difficulties
when engaging the hose over the tube, especially if the parts
are anything other than clean or access to the parts is
restricted. Once this is done, the clamp, which was put over
the hose before engagement in the tube, is located around the
hose, just behind the bead on the tube. The clamp is then
tightened by turning the screw with a tooL such as a screw
driver. Again, an operator may experience difficulties when
locating and tightening the clamp in the restricted space of the
engine compartment in the limited time available to him to
complete the operation as the automobile on the assembly line
passes through his work station.
As there is no visual indication o whether the clamp
is correctly located and tightened, other than obvious
misalignment or loosenesfi, the presence of an incorrectly fitted
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1 3202~5
clamp does not become apparent until the automobile is fully
assembled and the engine cooling system has been filled with
cooling fluid and the engine run for a period of time to build
up pressure in the system. This is particularly important on an
assembly line where an incorrectly fitting clamp may not be
detected until the engine is tested, or even in some instances
until after the automobile has been in use for some time
resulting in a customer warranty claim. Consequently, the
assembly line must accommodate stations to check and tighten
hose clamps.
In addition to the problems outlined above, this
conventional form of coupling is unsuited for fitting in fully
automated automobile assembly lines due to the number and
intricacy of the steps involved in the assembly of the hoses and
clamps. It is, therefore, an object of the present invention to
provide a pipe coupling which can be connected with a minimum of
operational steps which are of a nature to permit the use of
robot0 or the like to connect the coupling. Further objects of
the inventlon include providing a coupling which can be quickly
and easily disconnected and providing means to indicate whether
the coupling has been made correctly.
Accordingly, in one of its aspects, the present
invention provides a pipe coupling comprising a tubular male
fitting defining an external conical portion and a tubular
female fitting adapted to fit snugly about the male fitting and
including a complementary internal conical portion. A seal is
seated in one of the conical portions for engagement with the
other of the portions to seal the male and fernale fittings.
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Axially oriented guide means are provided to allow relative
angular location of the male and female fittings and to permit
relative axial movement of the fittings and locking means are
coupled to the male and female fittings for locating the
fittings axially with respect to one another on assembly.
According to another aspect of the invention, a pipe
coupling is provided having tubular male and female fittings
adapted to fit together snugly, a seal seated in one of the
fittings to seal the fittings after assembly, the fittings
defining locking means including at least two curved resilient
arms extending circumferentially from one of the fittings, the
arms having end portions defining engagement means cooperable
with receiving apertures in the other of these fittings to
engage the apertures and retain the fittings in axial
relationship with the seal in engagement with both fittings to
seal the fittings.
A preferred embodiment of the present invention will
now be described, by way of example, with reference to the
accompanying drawings, in which:
Fig. 1 is a broken away perspective view of a typical
automobile radiator and hose provided with a pipe coupling in
accordance with the present invention, the pipe coupling having
a male fitting and a female fitting, and the fittings being
shown separated and aligned ready for engagement;
Fig. 2 is a perspective view of the male and female
fittings of the coupling of Fig. 1, the male fitting being shown
rotated through 90 degrees from the engagement alignment to
illustrate more details of the male fitting;
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Fig. 3 is an end view of the male fitting of Fig. 1
looking from the end exposed in Fig. 2;
Fig. 4 is a sectional side view on a diameter of the
male and female fittings after assembly and taken generally on
line 4-4 of Fig. l; and
Fig. S is an enlarged view of a portion of Fig. 4
showing a seal ring in the male fitting and engaged with the
female fitting.
Referring initially to Fig. 1 of the drawings, a pipe
coupling, indicated generally by reference numeral 20, extends
about a longitudinal axis and comprises two mouldings, typically
of synthetic plastics material and preferably of glass filled
nylon, in the form of a tubular male fitting 22 and a tubular
female fitting 24. The male fitting 22 is connected permanently
to the end cf a flexible rubber hose 26 using any suitable
device and the female fitting is formed as part of a moulded
header 28 of an automobile radiator 30. Together the fittings
deflne a locklng structure 80 that with proper alignment, the
male and female fittings can be snapped together to form a
llquid seal and structure is provided to permit the fittings to
be ~eparated.
Reference is next made to Fig. 2 which shows the
flttings 22 and 24 in more detail. The male fitting 22, which
has a fluid passage 32 therethrough, comprises a hose connection
tube 34, an intermediate portion 36, and a leading end portion
3~.
The hose connection tube 34 is cylindrical and has a
raised bead 40 at its free end to form an interference fit with
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t 320235
the hose 26 (Fig. 1) and to help retain a crimped wedding band
clamp 42 which holds the hose 26 firmly on the tube 3~.
The intermediate portion 36 is of greater diameter than
the hose connection tube 34 and is provided with two
diametrically opposed resilient arms 44, 46 which are dependent
from the intermediate portion at diametrically opposed points
and which extend part circumferentially around and radially
spaced from the portion 36 (Fig. 3). On the outer end of each
arm 44, 46 there is provided a raised substantially rectangular
projection 48 having a grooved outer face 49. Adjacent each
projection 48 on the arms 44, 46, there is also provided a
detent projection 50, which has a tapered leading edge 52 and a
rearwardly facing abutment face 54.
The arms 44, 46 extend from raised bosses 56 which
define respective ones of a pair of guide slots 58. The leading
ends of the guide slots 58 are widened to provide a flared lead
in portion 62. Each of the bosses is provided with a raised
longitudlnally extending abutment 64 to locate the intermediate
portion 36 centrally as it is moved axially into the female
flttlng 24.
The fitting 22 tapers between the portion 36 and
leading end portion 38 at a 25 degree angle to the axis of the
fitting to form a truncated cone shaped portion 66, the outer
surface of which defines a seating for a seal. This seating is
in the form of a circumferential groove in which the seal sits
as will be seen in Fig. 5. The seal i5 indicated in Fig. 5 as
69 and the groove as 68 and is in the form of a lip of resilient
material, preferably E.P.D.M., having a mounting portion 69a
1 320~35
which is located in the groove 68 and a tapered portion 69b
which extends from the groove ~8.
The leading end portion 38 of the male fitting 22 is
cylindrical and is shaped to be received by an inner receiving
portion 70 of the female fitting 24 to stabilize the assembly
and prevent misalignment. The inner receiving portion 70 is
joined to the radiator header 28 and has a fluid passage 71 in
communication therewith. The inner portion 70 extends inwardly
from a flared portion 72, the inner face 73 of which is
complementary to that of the conical portion 66 of the male
fitting 22 (see also Fig. 5). The inner face 73 has a machined
finish to avoid a mould parting line which would possibly
interfere with the ability of the lip 69 to seal against the
face 73.
A mouth portion 74 of the female fitting 24 leads to
the flared portion 72 and receives the intermediate portion 36
of the male fitting 22. For this purpose the mouth portion 74
i~ provided with two diametrically opposed open ended axial
~lots 76 for receiving t'ne end pro~ections 48 on the arms 44, 46
and is further provided with two rectangular apertures 78 near
the respective slot~ 74 for receiving the detent projections 50
on the arms 44, 46. The engagement of the male fitting into the
female fitting requires angular positioning to ensure that the
parts meet correctly. This is achieved by two diametrically
opposed keying members 80 raised inside the mouth portion 74 for
location of the guide slots 58 in the male fitting 22. The lead
in portion 62 of slot~ 58 facilitate alignment.
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The male fitting 22 is engaged in the female fitting
24, simply by moving the male fitting into the female fitting
with the members 80 and slots 58 aligned. The tapered leading
edges 52 of the detent projections 50 will contact the outer
edge of the mouth portion 74 as the fittings 22, 24 are brought
together and these tapers will cause the arms 44, 46 to be
deflected radially inwards. The movement continues until the
detent projections 50 occupy the apertures 78 at which point the
arms 44, 46 spring outwards and the fittings are fully engaged.
The abutment faces 54 of the projections now bear against the
outer or opposing face of the aperture wall to locate the
fittings axially and to prevent separation of the fittings 22,
24 (Fig. 4) so that the seal 69 is in firm engagement with the
inner face 73. It is an advantage of the structure that the
movement of the detent projections 50 into the apertures 78
causes an audible click which serves to indicate that the
coupllng has been made and that a predetermined axial load has
been applied to the seal.
The seal between the fittings 22, 24 is achieved
between the inner ~ace 73 of the flared portion 72 and the lip
seal 69. The location of the lip seal 69 on the conical portion
66 allows the operator to visually inspect the condition of the
seal 69 before engagement of the fittings 22, 24 while
protecting the seal 69 from damage during handling and
shipping. Also, as the seal 69 does not contact the inner
surface 73 of the flared portion 72 until just before the
fittings 22, 24 are locked together the seal 69 does not wipe
along any appreciable length of surface while the fittings 22,
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24 are being pushed together and the likelihood of damage to the
seal 69, or of the seal 69 being rolled out of the slot 68
during this operation, is minimized. Most importantly, the
location and form of the seal 69 compensates for necessary
manufacturing tolerances which prevent the perfect mating of the
inner face 73 of the female fitting 24 and the conical portion
66 of the male fitting 22.
When the fluid pressure inside the automobile cooling
system, and thus also the fittings 22, 24, rises, the seal 69
inflates and is pushed into contact with the inner face 73 of
the flared portion 72. If there is a negative pressure within
the system as may occur when the fluid in the system cools, the
resilience of the seal 69 is sufficient to maintain sealing
contact with the face 73 and prevent air being drawn into the
cooling system through the fittings 22, 24.
The effect of vibration on the effectiveness of the
seal i3 limited by locating the seal at the mid-point of the
relatively long (50 mm) engaging surfaces between the male and
female fitting 22, 24. Minor vibrations between the fittings
22, 24 will occur because of the moulding tolerances needed for
ease of assembly.
The configuration of the fittings 22, 24 makes them
suitable for use on an automated assembly line and, if required,
locations can be integrally moulded on the exteriors of fittings
22, 24 to allow them to be held by robotic arms. A single axial
movement i8 sufficient to engage the fittings, the tapered
leading edges 52 of the detent projections 50 serving to push
the arms 44, 46 inwardly to permit coupling. The provision of a
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lead-in portion 62 to the guide slot 58 allows fittings 22, 24
to be coupled when initially misaligned by as much as 12
degrees. If the misalignment is greater than 12 degrees the
fittings 22, 24 will not engage.
I n the pipe coupling shown in the drawings the keying
members 80 and the guide slots 58 are diametrically opposed on
their respective fittings 22 and 24. As the slots 75 and the
end projections 48 on the arms 44, 46 are similarly opposed the
fittings 22, 24 may be engaged in two different orientations
spaced 180 degrees apart. In certain situations it may be
desired that the fittings may only engage in one relative
orientation in which case the guide slots 58 and the keying
members 80 are located asymmetrically on the respective fittings
22, 24.
At an inspection point on such an assembly line
uncoupled fittings are easily detected and if an incorrectly
coupled fitting should pass an inspection the coupling will fail
when the cooling system is filled with cooling fluid due to the
minimal internal pressure which would be sufficient to separate
the coupllng.
When later maintenance of the automobile cooling system
requires the coupling to be disengaged, this may be easily
achieved, once the system is de-pressurised, by pressing on the
projections 48 to disengage the detent projections 50 from the
apertures 78 and pulling the fittings 22, 24 apart. Similarly,
inspection and replacement of the lip seal 69 can be easily
carried out
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1 320235
Should the hose 26 fail the wedding band clamp 42 is
cut to allow the male fitting 22 to be separated from the hose
26. The fitting 22 may then be installed on a new hose and held
in place with a conventional clamp. Alternatively a new hose
can be supplied complete with a new fitting 22.
The coupling 20 has been described herein as being used
to couple an automobile radiator to a hose. While the coupling
is well suited to such application it can also be used in any
number of applications where two conduits are to be joined.
Structures for such purposes are within the scope of the
invention as described and claimed. More particularly, the
locking structure formed by the arms 44 and 46 and associated
apertures 78 could be varied. For instance, the arms could be
formed in the female fitting with recesses in the male fitting.
Similarly, recesses could be formed in the arms with projections
on the corresponding part for engagement.
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