Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a joint between tubes
having a double wall structure comprising a corrugated outer ~ -
wall and a smooth or reversedly corrugated inner wall joining ~ .
the roots of the outer wall, and a lock ring applied around :
the tube ends and engaging a crest of the corrugated outer :. .
wall of each tube.
An object of the invention is to provide a simple
joint between tubes of the kind referred to wherein the specific ~.
characteristics of such tubes are utilized and which comprises
10 a minimum of elements so that the joint will be of a simple .-
structure and thus can be produced at low costs.
The tube joint can easily be mounted and demounted .
and provides a reliable seal and connection between the tubes.
Additional objects and advantages of the invention :
will be set forth in part in the description which follows and
in part will be obvious from the description, or may be learned ;
by practice of thc invention. The objects and advantages of
the invention may be realized and attained by means of the
instrumentalities and combinations particularly pointed out in ~-
the appended claims.
To achieve the foregoing objects and in accordance
with the purpose of the invention, as embodied and broadly
described herein, there is provided a tube joint of the type
referred to above, characterized in that the tube ends termin-
ate in.a plane which passes through a crest of the outer wall
to define in each tube
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645
end an annular space open at the tube end, between the outer
and inner walls, an annular sealing ring disposed between the
tube ends being received in said spaces, and further characterized
in that the lock ring disposed about the tube ends is arranged to
press the ends against the intermediary annular sealing ring
from opposite sides thereof when tightened about the tube ends.
~ he accompanying drawings, which are incorporated in
and constitute a part of this specification, illustrate an em-
bodiment of the invention and,! together with the description, .
10 serve to explain the principles of the invention. :
Of the drawings: .
FIG. 1 is a perspective view of the tube joint accord- -
ing to the teachings of the invention; ~. .
FIG. 2 is a vièw partly in elevational side view and
partly in longitudinal sectional view of the tube joint; . :
FIG. 3 is a cross sectional view of the tube joint . :
along line III-III in FIG. 2;
FIG.` 4 iS a perspective view of the lock ring forming
part of the joint, in opened or disengaged condition; and
; FIG. 5 is a perspective view of the lock ring in closed
or engaged condition.
The two pipes ~oined are of a double wall structure ~ ~
well-known per se and comprise each a corrugated outer ;.
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wall lO e.g. of extruded and then in moulds vacuum formed
plastic material, and a smooth cylindrical inner wall ll also
of extruded plas-tic material, which is connected or fused to
the roots of the corrugated outer wall at 12 so that the double
wall structure comprises a number of circumferential annular
spaces 13 each closed lndividually, and grooves 14 provided -
therebetween. In the embodiment illustrated the corrugation
of the outer wall is substantially of trapezoid cross sectional
form but other forms are conceivable. A smoothly corrugated ;~
outer wall having substantially sinusoidal curvature is not
uncommon in connection with tubes of the kind referred to, and
it is of course also conceivable to combine a corrugated outer
~ wall with an inner wall also corrugated, which is reversed in
i relation to the outer wall such that the crests of the inner
wall are connected or fused to the roots of the outer wall. In
`1 the latter case the corrugation of the inner wall need not
necessarily be exactly "out of phase" to that of the outer
wall; however, ~he pitch of the inner wall should be the same
as that of the outer wall.
Eaah tube end terminates in a plane which passes
through a crest of the outer wall. ~owever, it is not neces-
sary that this plane passes through the centre of the crest;
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for instance in the case, as shown, when the crest is of trape-
zoid cross sectional form, it is not necessary that the~plane
pass through the top of the crest. Similarly this is not a
requirement in the case wherein the corrugation is sinusoidal
or of similar form. Terminating as described, each tube end
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forms an annular space 15 open at the end and defining between
the outer and inner walls a space for receiving a sealing ring
16, such as a ring of elastic material e.g. rubber or plastic,
which is recei~ed partly by the space in one tube end and partly ,,
by the space in the other tube end. However, the tube ends are ',,
mutually spaced before they are clamped together as will be
described below so that they can be pressed against each other -
with the sealing ring being squeezed between the tube ends. In
the embodiment disclosed sealing ring 16 is of substantially
X-formed cross sectional form which is preferred since the arms
of the profile are brought to seal effectively against the
corners of spaces 15 when the tube ends are pressed together. ~ ,
The tube ends are pressed together by means of an
external lock ring 17 which is disclosed in FIGS. 4 and 5 and
comprises a slotted ring 18 e.g. of plastic or metal, which is
~ channelled in cross section, the flanges of which diverge
,~ towards the free ends thereof. At one s,ide of slot 19 the ring ~ '
is formed with a hook 20 or other projection on the outside
thereof close to the slot. At the other side of the slot there ;,
'- 20 is connected to ring 18, by means of rivets 21, a straplike
flap 22 of plastic or metal sheet. This flap is disposed on ,,
- ~he outside of the ring and joins the ring substantially
, tangentially spaced about 90 from the slot. It projects freely ~ ,
,- from the ring towards the slot and beyond the
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adjacent end of the ring. To the major part thereof t~e flap
is spaced from the ring but it is fle~ible towards and away from
the ring. At the ~ree end thereof whicn has a greater width
than the rest of the flap, the flap forms a rectangular opening
23 which extends in the longitudinal direction of the flap and
is sufficiently large to receive hook 20.
By further expansion of lock ring 17 from the condition
disclosed in FIG. ~ the lock ring can be applied over the two tube
ends transversely to receive the two terminating crests thereof
la which each form a space 15, between the flanges of ring 18. Then,
lock ring 17 is tightened circumferentially about the tube ends
by means of pliers, a screwdriver or another suitable tool, and
hook 20 is engaged with slot 23 in flap 22 so that the lock ring
will be brought to the closed condition shown in FIGS. 1 r 2, 3
and 5.
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Sealing ring 16 should have such a width that the two
terminating crests, when the sealing ring is not squeezed, are
,:
spaced a distance determined by the sealing ring, which allows the ~
lock ring to be thread transversely over the terminating crests ~ -
at the outer ends of the ring flanges. Then, when the lock ring
is being tightened about the tube ends as described the flanges
of slotted ring 18, diverging towards the free ends thereof, slide
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along the inclined sides of the terminating crests so that---the tube
. ends are moved axially towards each other by cam action between
the tubes and
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the lock ring the tubes being pressed against the sealing ring
16 which is squeezed and substantially fills the annular spaces
15, spanning the joint between the tubes to provide a seal there- -
between.
By using a sealing ring and a lock ring there is thus
provided a joint between the tubes by utili~ing the specific wall
structure without the necessity to form the tubes in any specific
way in the area of the joint. The tubes can be cut at any place
of the length thereof through a crest and can be joined according
to the principles of the invention by using particularly simple
means for obtaining the necessary seal between the tube ends.
It will be apparent to those skilled in the art that
various other modifications and variations in addition to those
mentioned above could be made in the tube joint of the invention
without departing from the scope and spirit of the invention.
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