Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to a connecting assembly capable of provid-
ing a connection with supply lines carrying gaseous or fluid media, which
assembly comprises a non-symmetrical connecting member designed in the form
of a clamping tool to embrace the end of a supply line inserted into the con-
necting member, and another member, the two members being assembled by inser-
tion of one into the other, and secured by means of an annular quick-release
lock consisting of an annular groove in one of the members and a continuous
pro~ection on the other member whereby these members, assembled into one
connecting assembly, provide a continuous passage, both having a central bore.
A connecting assembly of this kind is described in the
DOS 25 28 757. The connecting member is inserted into the other member and
an annular groove around the internal circumference of the other member cor-
responds to an annular projection on the external circumference of the con-
necting member. With this arrangement, the diameter of the quick-release
lock is relatively small and the effective axial loading area of the connec-
tion between the two surfaces of the groove and projection, is correspondingly
small. In consequence thereof there are created a number of unfavourable
conditions when high axial forces are present or when the media in the supply
lines are streaming alternatingly in opposite directions and create pulsating
loads. This is especially unfavourable when the two members of the connect-
ing assembly are made of a plastics material because the surface pressure may
be so high that it resiliently expands the other member and elastically com-
presses the connecting member which is inserted into the latter, at least in
the area of the annular lock. This condition may lead to the unintentional
release of the lock. In addition to this there is the danger of the annular
projection being torn off under shear loads resulting from an excessive sur-
face pressure, especially with connecting assemblies assembled from a member
made of a plastics material, and a connecting member made of metal.
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Another drawback which is due to the relatively small diameter of
the ~nnular quick-release connection is explained below: The resilient
expansion of the other member, and the elastic compression of the connect-
ing member, aggravated by the danger of shearing the projection off, depend
substantially on the choice of the materials used in the manufacture of the
other member. It is easy to see that a member consisting of metal will
hardly be resiliently expanded under axial loads. However, the danger of
shearing is greater, especially when the adjacent connecting member consists
of a plastics material. This danger may be counteracted by a correspondingly
resistant profile of the annular projection. This dependency on the struc-
tural materials makes it necessary to provide two different connecting mem-
bers of different dimensions when a connecting assembly is used with supply
- lines having different diameters, to be suitable for the other member which
may be manufactured of metal or of a plastic material.
It is an object of the present invention to provide a connecting
assembly of the type referred to above which, in order to avoid the above
drawbacks, is designed in such a manner that the danger of excessive axial
surface pressure does not occur.
According to the invention there is provided a connecting piece for
supply lines carrying gaseous or fluid media, comprising: a first elongated
and hollow connecting member having a first central body segment with an
enlarged end structure on one end terminating in a first axially facing
surface which has a first axially facing recess therein communicating with
the interior of said hollow connecting member and opening in a direction
remote from said first central body segment, the bottom of said first recess
defining a second axially facing surface extending parallel to said first
surface, said first recess having an annular recess on the internal surface
thereof intermediate said first and second surfaces, a supply line clamping
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means connected to said first central body segment on an end thereof
remote from said enlarged end structure; a second elongated and hollow
connecting member having a second central body segment with an end segment
extending away from said second central body segment and a sleeve segment
extending axially away from said second central body segment on a side
thereof opposite said end segment, said sleeve segment having a cross-
sectional size less than the cross-sectional size of said second central
body segment to thereby define a third axially facing surface facing in a
direction toward said first surface on said first connecting member, said
sleeve terminating in a fourth axially facing surface parallel to said third
surface, said fourth surface having a second axially facing recess therein
communicating with the interior of said second connecting member, the bottom
of said second recess defining a fifth axially facing surface extending
parallel to said third and fourth surfaces, the axial spacing between said
third and fourth surfaces on said second connecting member being equal to
the axial spacing between said first and second surfaces on said first
connecting member, said sleeve segment having an annular projection on the
external surface thereof intermediate said third and fourth surfaces; said
sleeve segment being received ;n said first recess with said third surface
thereof engaging said first surface and with said fourth surface engaging
said second surface, a compressible seal member received in said second
recess and being compressed between said second and fifth surfaces, said
annular projection being operatively received in said annular recess to
hold said first and second connecting members in a coupled relationship
and said first and third surfaces as well as said second and fourth surfaces
in engagement with each other.
Embodiments of the invention will now be described, by way of
example, with reference to the accompany ng drawings, in which:-
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Figure 1 shows a first embodiment of the invention in a side view
and in longitudinal section,
Figure 2 shows a variant to the arrangement according to Figure 1
in a partly sectional side view, and
Figures 3 and 4 show two further embodiments of the invention,
namely a knee piece and a so-called T-shaped piece in a partly sectional
side view.
The connecting assembly shown in Figure 1 of the drawings is com-
posed of two sections, namely the connecting member 1 at one end, and the
threaded member 2 at the other end of the assembly. The connecting member 1
is designed in the manner of a clamping tool comprising a number of cla.mping
elements 3, 4 which are equidistantly arranged around the circumference and
separated from each other by slots 5. The clamping elements 3, 4 extend from
a central part 6 of the connecting member in a direction away from the thread-
ed member 2 so that the free ends of the tool elements 3, 4, are remote from
the threaded member 2. A clamping ring 7 which is movable in both axial
directions according to the arrows 9a is mounted on the external circum-
ference of the clamping elements 3, 4. In its effective extreme position
which is
- 3a -
13L~;32~
shown in the illustration, the ring presses the clamping tool elements to-
gether so that their initially cylindrical form is forced towards the inside.
An annular safety collar 8 at the outer end of the clamping tool prevents the
ring 7 from being unintentionally pulled off. When the clamping ring 7 is
moved in the direction of the arrow g and over a conical section 10 of the
connecting member 1 it assumes its ineffective position and the clamping ele-
ments 3, 4 may snap elastically towards the outside provided that the clamp-
ing ring 7 is located on the cylindrical, reduced diameter section 11, which
means that the opening between the clamping tool elements widens correspond-
ingly. There is moreover an annular, tooth shaped, pro~ection 12 whichextends around the internal circumference of the clamping tool elements 3, 4.
The tooth shaped annular pro~ection 12 is not sharp-edged so that
there results an ad~antageously small notch effect on the tube which is only
deformed (the tooth does not cut into the tube), so that with the connecting
assembly according to the invention there can be used soft and hard flexible
tubes or hoses and also so-called PM-tubes or pipes. It is further to be
seen that the tooth n ank 12a facing the threaded member is steeper than the
other tooth flank 12b, so that the insertion of the tube in direction of the
arrow 9 - the tube slides over the tooth flank 12b - is easier than the ex-
traction of the tube in the opposite direction.
At the end ad~acent to the threaded member 2 the connecting member1 has an enlarged diameter section 13 which is ad~acent to the cylindrical
section 11 having a smaller diameter, and is substantially cylindrical, its
bottom forming a radially directed shoulder 14. Finally, there is an annular
groove 15 which extends along the internal circumference of the wider part 13.
The threaded member 2, which has at one end a threaded part 16 to
connect for example with a rigid line made of metal, also has, ad~acent to
the part 16, in the direction towards the connecting member 1, an external col-
lar 17, which projects radially and may for example be of hexagonal shape sothat it can be operated with the aid of a wrench. Adjacent to this collar 17
is an annular projection 18 which is of a smaller diameter than the collar 17
and has on its external circumference a continuous nose 19 which, like the
annular groove 15, is fully annular, its cross-section corresponding to the
latter. A recess is cut out of the front surface of the threaded member 2
which is adjacent to the connecting member 1, the cut-out being annular and
radially extending towards the central continuous bore 20 which extends
through the threaded member and the connecting member, and also being open
on said front surface so that it may accommodate an 0-ring 22 consisting of
a sealing material.
The substantially cylindrical wider part 13 of the connecting member
1 is pushed over the annular projection 18 of the threaded member 2 whereby
the continuous nose 19 on the external circumference of the threaded member
engages with the corresponding annular groove 15 in the internal circumference
of the connecting member, constituting a quick-release lock. In the assembled
state the radially extending step 14 of the connecting member 1, which is
formed by the bottom of the wider part 13, rests against the front face of the
threaded member 2 so that the 0-ring 22 between the two members of the con-
necting piece is forming a seal. Moreover, with the assembled connectingassembly, the free end of the wider part 13 rests against the end face of the
collar 17 which is adjacent to the connecting member 1, providing a stop for
the end of the latter which was pushed over the other member. Finally it may
be pointed out when describing the physical features of the connecting assem-
bly that the collar 17 on the threaded member is axially spaced from the
front face of the latter, which is adjacent to the connecting member 1, and
also relative to the 0-ring 22.
It can be seen that the snapping and catching connection between
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the connecting member 1 and the threaded member 2 is absolutely secure and
reliable and can often be released or loosened only by destroying the indi-
vidual parts. This snapping and catching connection also enables the two
parts 1 and 2 to be turned with respect to one another about the longitudinal
axis.
Summarising, a connecting assembly is provided which comprises on
its threaded member 2 at a given spacing from its front face inserted into
the connecting member 1 a radially projectng collar 17 which may for example
be of hexagonal form, and adjacent to it an annular projection 18 which is
recessed relative to the collar 17, and inserted into the connecting member
1, and comprises on its external circumference an annular nose 19 and on its
internal circumference, in the region of the front face of the threaded member
2, a recess 21 which extends towards the central continuous bore 20 and is
open on said front face. ~he end of the connecting member 1 which is ad~acent
to the threaded member 2 comprises a substantially cylindrical, extended
diameter section 13 which embraces the annular extension 18, its free end
butting against the collar 17 and one of its radial steps 14 which constitutes
the bottom resting against the end face of the threaded member 2, an annular
groove 15 whose cross-section corresponds to the continuous nose 19 on the
annular projection 18 at the internal circumference of the wider part 13.
For the sake of completeness it is mentioned that the process of
assembling begins with withdrawing the clamping ring 7 from its effective
into its ineffective position, so that the end of the supply line may be
inserted into the connecting piece 1 until it butts against the central step
24 in the continuous bore 20 in the threaded member 2, followed by pushing
the clamping ring 7 back into its effective position. Since the radial dimen-
sion of the circular step 24 corresponds to the wall thickness of the supply
line the through-flow cross-section is constant throughout its entire length.
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The arrangement according to the invention can be used in connection
with not calibrated soft and hard flexible tubes or hoses manufactured nor-
mally from polyethylene, polyamide, or polyurethane, or in connection with
rigid tubes or conduits consisting of polyethylene and aluminum (type "PM-
Dekabon") which are stiff but can be easily bent by hand.
It follows from the above that the annular groove 15 and the cir-
cular pro~ection 19 are located relatively near to the outer surface of the
assembly which means that the diameter of this quick-release lock is large.
In this manner it has been achieved that the contact area between the annular
groove and pro~ection is correspondingly large in the axial direction. In
other words, a large surface is available for the absorption of axial forces
created for example by mechanical tensile forces or by pulsating loads in the
supply lines, so that the corresponding surface pressure in the quick-release
lock is too small to widen elastically the wider part 13. The surface pres-
sure in the connection is also too small to shear the annular projection 19
off, even in the case of threaded members 2 consisting of a plastics material.
Whereas the connecting assembly described in the German DOS
25 28 757 comprises an O-ring which is more centrally located inside the
threaded member, and the connecting member inserted into the threaded member
extends to the O-ring, the assembly according to the invention is different
and offers thereby the following advantages over the above.
In the assembled state the connecting member 1 rests against the
operating collar 17. It is therefore easy when mounting the parts to ascer-
tain from the outside that the two connecting members of the connection are
correctly joined to each other and thus to avoid pushing the connecting member
too far or not far enough.
Plastic connecting members are preferably manufactured by in~ection
moulding because in this case the annular groove 15 is formed with the aid of
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~ 4D
a collapsible core, the latter being a form core the cross-section of which
may be reduced in a tapering manner to facilitate the removal of the product.
Although the moulding process with a collapsing core entails the drawback of a
longitudinal seam extending over the internal circumference of the wider part
13 this will not interfere at all with operations. The comparable longitudi-
nal seam developed in the case of the connecting piece according to the
D06 25 28 757, however, which is located on the internal circumference of the
threaded member extends up to the region of the O-ring and this may adversely
affect the tightness of the assembly.
With hexagonal collars 17 the wall thickness of the threaded member
cannot be constant in the region of the collar. When the collar is made of
a plastics material the theoretically circular bore is bound to become
slightly untrue because of the non-uniform shrinkage of the synthetic material
while it solidifies at positions varying in thickness. This slight distor-
tion of the continuous bore in the region of the collar decreases in the case
of the present invention towards the O-ring 22, bearing in mind that the
recess 21 for its accommodation was cut out at a given distance from the col-
lar 17. The recess 21 is therefore truly circular and the effect described
above does not affect the sealing quality. In contrast, the collar and the
O-ring used with the assembly according to the DOS 25 28 757 are located in
the same plane and it may therefore easily happen that the sealing seat is
out of circularity.
Further advantages of the invention are: the tube fits securely
and snugly to the said connecting piece, even when the load is alternating,
so that in this case the connection is not influenced disadvantageously;
further, the assembling and disassembling operations can be performed by
hand due to the fact that the clamping ring is easily accessible and that
the shape is so as to be most favourable for good handling. Only a small
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pushing force must be exerted on the clamping ring due to the optimal shape
of the clamping elements. For disassembling only one hand i5 necessary. The
operations "clamping" and "pulling the tube" are separated. Incidentally,
the tube can be cut off even obliquely, for example, up to 2mm.
The embodiment according to Figure 2 - all parts consist of syn-
thetic material - differs from the embodiment according to Figure 1 only by
its dimensions and by its shape: the hexagonal part 30 of the threaded mem-
ber has the same diameter as the annular groove 31 on the connecting member 32
which cooperates with the annular pro~ection 33; 34 is the clamping or chuck-
ing tool, 35 the clamping ring. In Figure 3 there is shown a right-angled
connection assembly, having a knee piece 40 which is inserted between the
threaded piece 41 and the connecting member 42 by interposing therebetween,
respectively, an O-ring 43, 44. In Figure 4 there is shown a T-shpaed piece
as a so-called "plug-in-distributor" which has three connecting pieces or
sockets 50, 51 52 interconnected with one another, respectively, via the
centrPl distributing piece 53 with three legs 54, 55, 56 and two connections
or ~unctions 57, 58.
