Note: Descriptions are shown in the official language in which they were submitted.
1~4~
SPECIFICATION
COUPLING FOR CORRUGATED CONDUIT
- sAcKGRouND OF T~E INVENTION
1. Field of the Invention
The present invention is directed to a coupling for a
corrugated conduit, and more particularly to such a
coupling utilized as an attachment of an end of the
corrugated flexible conduit to a device or fitting with
which the fluid medium conveyed by the conduit is
utilized.
2. Description of the Prior Art
Such couplings for the corrugated conduit or hose
have been extensively utilized in gas conveying system as
well as in other fluid conveying systems. A typical
prior coupling for the corrugated conduit is shown in
Japanese unexamined Patent Publication (KOKAI) No.
60-73193 in which the end of a corrugated conduit is
;~1 clamped by a nipple and is inserted together therewith
into a sleeve on one side of a main tubular body. A nut
is threaded on the sleeve to have a collar at its end in
abutting engagement with the rear end of the nipple for
pressing the nipple together with the end of the conduit
~5 forwardly into the sleeve, forcing the latter into
sealing engagement with an annular shoulder projecting
radially inwardly of the tubular body. In this prior
coupling, however, the nipple is shaped to have a
circular external configuration relatively freely
l rotatable within the sleeve so that it tends to be
rotated by the frictional force developed at the abutment
between the nut and the nipple as the nut is rotated on
the sleeve in advancing the nipple and the end of the
conduit into the sleeve, thereby subjecting the conduit
~k
1~41~i6~3
to twistlng or kinking forces which would damage the
conduit or render the subsequent procedures to be rather
inconvenient.
SUMMARY OF THE INVENTION
r The present invention has been accomplished in view
of the above shortcoming and provides an improved
coupling for a corrugated conduit. The coupling in
accordance with the present invention comprises a main
tubular body having a sleeve at its one end defining
n therein a conduit receiving bore terminating at its inner
end in an annular shoulder projecting radially inwardly
of the main tubular body midway between the ends of the
axial bore. A nipple is provided for clamping an end
portion of the conduit with corrugations of the conduit
~5 left projecting beyond the forward end of the nipple and
is inserted into the conduit receiving bore of the sleeve
together with the end portion of the conduit. A series
of serrations are formed interiorly of the nipple to be
in registering engagement with the corrugations at the
end portion of the conduit for firmly gripping the
conduit. Said nipple has its rear end abutted against a
collar at one end of a nut threadedly fitting about the
sleeve to be thereby pressed forwardly into the sleeve in
order to force the end of the conduit into pressing
engagement with the annular shoulder as the nut being
rotated. The characterizing feature of the present
invention resides in that said nipple being shaped to
have a polygonal exterior configuration to be fitted in a
correspondingly shaped section of said conduit receiving
bore so as to be slidably but unrotatably inserted in the
sleeve. With this result, the nipple and the end portion
of the conduit can be pressed into the sleeve without
being rotated, obviating the occurrence of twisting or
1~4~6~
kinking of the conduit while ensuring effective pressing
contact between the end of the conduit and the shoulder.
Accordingly, it is a primary object of the present
invention to provide a coupling for a corrugated conduit
5 in which the conduit is free from being subjected to
twisting or kinking forces at the time of rotating the
nut for securing the conduit to the sleeve.
In a preferred embodiment, said nipple is prepared in
the form of a split member composed of a pair of
11l semicylindrical halves connected by an integral
thin-walled hinge portion to be easily separable
therefrom. The nipple is in use to be separated into the
two halves which are then placed about the end portion of
the conduit with the serrations being in registering
engagement with the corrugations of the conduit so as to
be inserted into the sleeve as clamping the end portion
of the conduit. With the use of this split nipple, the
corrugations at the end portion of the conduit can be
readily brought into registering engagement with the
~o serrations of the nipple so that the end portion of the
conduit can be securely and firmly gripped by the nipple.
It is therefore another object of the present
invention to provide a coupling for a corrugated conduit
in which the end portion of the conduit can be easily and
.~5 firmly clamped by the separable nipple.
Formed at the juncture of the shoulder and the
conduit receiving bore of the sleeve is an annular groove
for receiving therein a sealing ring which is to be
disposed around the end of the conduit pipe when it is
forced into pressing contact with the shoulder. The
sealing ring has its side in abutting relation with the
forward end of the nipple so that it is compressed
axially by the nipple inserted in the sleeve to
elastically expand radially for establishing sealing
4~
contacts between the sealing ring and the wall of the
groove and between the sealing ring and the end of the
conduit being pressed against the shoulder. I~ this
sense, the nipple pressed forwardly into the sleeve by
the nut can serve not only to guide the end of the
conduit into pressing engagement with the shoulder but
also to effectively deform the sealing ring for the
purpose of providing an increased seal between the
conduit and the sleeve.
11l It is therefore a further object of the present
invention to provide a coupling for a corrugated conduit
capable of increasing the effectiveness of the seal
between the conduit and the sleeve.
These and other objects and advantages of the present
l! invention will be more apparent from the following
detailed description of the embodiment when taken in
conjunction with the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a coupling
-/r, for a corrugated conduit in accordance with a preferred
embodiment of the present invention;
FIG. 2 is a vertical cross section of the coupling;
FIG. 3 is an end view of a main tubular body of the
coupling;
FIG. 4 is an end view of a split nipple employed in
the coupling;
FIGS. 5 and 6 are end views respectively showing a
split nipple and a main tubular body employed in a first
modification of the above embodiment; and
~q FIGS. 7 and 8 are end views respectively showing a
split nipple and a main tubular body employed in a second
modification of the above embodiment.
~4~j6~
-- 5
DETAILED DESCRIPTION OF THE EMBODIMENT
Referring now to FIG. 1, there is shown a coupling
for a corrugated conduit 1 embodying the present
invention. The coupling comprises a main tubular body 10
5 having an axial bore 11 and having on its one end portion
an externally threaded sleeve 12. The other end portion
of the main tubular body 10 defines a head portion
including a hexagonally shaped flange 13 and a male
member 19 being in the form of an externally threaded
1f! tapered barrel and projecting outwardly from the flange
13 for connection with any suitable devices or fittings.
Said sleeve 12 defines therein a conduit receiving bore
15 of hexagonal configuration which has a diameter larger
than the rest of the axial bore 11 and terminate at its
15 inner end in an annular shoulder 16 projecting radially
inwardly midway between the ends of the axial bore 11.
Said corrugated conduit 1 is made of metallic material to
include a series of uniform corrugations having
relatively rounded crests alternated by relatively
rounded roots, as best shown in a longitudinal
cross-sectional view of Fig. 2, and is relatively
thin-walled to be flexible.
For connection of the corrugated conduit 1 to the
main tubular body 10, the conduit 1 is inserted as being
_5 clamped by a nipple 20 into said conduit receiving bore
15 of the sleeve 12 together therewith and is secured by
rotating a nut 30 threadedly engaged on the sleeve 12.
Said nipple 20 is shaped to have a hexagonal exterior
configuration to be slidable but unrotatably inserted
l into said hexagonally shaped conduit receiving bore 15 of
the sleeve 12. Formed internally of said nipple 20 are a
series of serrations 21 which are in intimate mating or
registering engagement with the corrugations of the
conduit 1 to firmly grip the latter. As shown in Fig. 4,
4~
the nipple 20 is prepared in the form of a split tube
composed of a pair of semicylindrical halves 22 connected
by a thin-walled hinye portion 23 diametrically opposed
to a slit 2D. to be easily separable thereat. Said nut 30
5 threaded on the sleeve 12 includes a radially inwardly
projecting collar 31 at its rear end, said collar 31
encircling an aperture 32 which has an internal diameter
larger enough for freely passing therethrough the
corrugated conduit 1 but smaller than the maximum
l external diameter of the nipple 20 so that the collar 31
is to be in abutting engagement with the rear end of the
nipple 20.
In assembling the coupling, the first step is to
extend the end portion of the corrugated conduit 1
~5 through the nut 30 and to separate the nipple 20 into two
semicylindrical halves 22 by cutting the hinge portion
23, which halves 22 are then placed about the end portion
of the conduit in such a manner as to leave a few row of
corrugations at the extreme end of the conduit 1 to
~0 project beyond the forward end of the nipple 20 and to
register the serrations 21 into mating engagement of the
corrugations of the conduit 1. The end portion of the
conduit 1 thus clamped by the nipple 20 is inserted
together with the latter into the conduit receiving bore
?5 15 as the hexagonally shaped nipple 20 being guided by
the correspondingly shaped conduit receiving bore 15.
Thereafterl said nut 30 is threaded on the sleeve 12 with
the collar 31 abutting against the rear end of the nipple
20. Advancing or rotating the nut 30 presses the nipple
:10 20 and the conduit 1 held thereby deep into the sleeve 12
to thereby force the end of the conduit 1 into pressing
contact with said shoulder 16, at which occurrence the
corrugations left projecting beyond the nipple 20 are
collapsed between the forward end of the nipple 20 and
4~
the shoulder 16 so as to provide an effective seal around
the entire periphery of the conduit end therebetween even
though the end of the conduit 1 is not cut exactly
square. It is to be noted at this time that since the
split nipple 20 is cut into the two semicylindrical
halves 22 which are symmetrical to each other they can be
successfully placed about the end portion of the conduit
1 even if one of them might be reversed its longitudinal
direction at the situs of the assembling, facilitating
tU the assembling procedures.
Formed at the juncture of the shoulder 16 and the
conduit receiving bore 15 is an annular groove 17
receiving therein a sealing ring or O-ring 18 for
improving the sealing effect between the shoulder 16 and
the conduit end. The sealing ring 18 has an internal
diameter slightly smaller than the conduit 1 in order
that the collapsed end 2 of the conduit 1 is press fitted
into the sealing ring 18 to elastically deform it
radially outwardly when the conduit 1 is pressed against
~o the shoulder 16. The external diameter of the sealing
ring 18 is larger than the minimum external diameter of
said nipple 20 so that the sealing ring 18 has its side
in abutting relation to the forward end of the nipple 20.
Thus, the sealing ring 18 is axially compressed by the
r/~ front end of the nipple 20 to be thereby elastically
deformed radially so as to provide tight sealing
engagements between the sealing ring 18 and the
corrugated end 2 of the conduit 1 as well as between the
sealing ring 18 and the walls of the groove 17, assuring
a complete seal between the conduit 1 and the sleeve 12
or the main tubular body 10. Said sealing ring 18 may be
of circular, rectangular or any suitable section for
ensuring the above sealing effect.
1~4~i6~
First and second modifications of the above
embodiment are shown respectively in Figs. 5 and 6 and in
Figs. 7 and 8, these modifications being identical in
construction to the above embodiment except for the
external configuration of the nipple 20A and 20B as well
as the internal configuration of the associated conduit
receiving bore 1 5A and 1 5B of the sleeve 15. For easy
understanding, the like parts are designated by like
numerals as in the above embodiment. In these
1~ modifications the nipples 20A and 20B are shaped to have
an star-shaped cross section characterized respectively
by a larger number of sharpened ribs 25A and by a smaller
number of rounded ribs 25B both of which are evenly
spaced circumferentially. The conduit receiving bores
1~; 15A and 15B of the modifications are correspondingly
shaped, permitting the respective nipples 20A and 20B to
be slidable but unrotatable within the sleeve 12.
Likewise in the above embodiment, each of the nipples 20A
and 20Bis provided with a slit 24A,24B and thin-walled
hinge portion 23A,23B by which it can be separated into
two semicylindrical halves symmetrical to each other.
It is contemplated that still other modifications and
changes can be made in the coupling disclosed without
departing from the scope of the invention.
~i
1~4~
LIST OF REFERENCE NUMERALS
1 corrugated conduit
2 collapsed end
10 main tubular body
11 axial bore
12 sleeve
13 flange
14 male member
15 conduit receiving bore
16 shoulder
17 groove
18 sealing ring
20 nipple
20A nipple
20B nipple
21 serration
22 semicylindrical half
23 hinge portion
23A hinge portion
23B hinge portion
24 slit
24A slit
24B slit
25 rib
30 nut
31 collar
32 aperture
_ q ,.
