NL2022580B1

NL2022580B1 - Tube connector with leak detection

Info

Publication number: NL2022580B1
Application number: NL2022580A
Authority: NL
Inventors: Siccama Hans
Original assignee: K Z Meet En Regelapparatuur B V
Priority date: 2019-02-14
Filing date: 2019-02-14
Publication date: 2020-08-27
Also published as: WO2020167115A1

Abstract

A tube connector for push-fit connection to a tube (5), comprising a hollow connecting body (2) for receiving a tube (5), a grab ring (6) arranged in the connecting body (2) and configured for c|amping engagement on the tube (5), and a resi|ient sea| ring (8) arranged in the connecting body (2) for sea|ed engagement around the tube (5). An e|ongated slider member (10) is |ongitudina||y arranged in the connecting body (2) and |ongitudina||y movabIe between a first and second position (P1, P2). The slider member (10) comprises a prong end (11) and an opposing hook end (12). The prong end (11) is configured to dislocate the seal ring (8) in the first position (P1) and the hook end (12) is configured to move the slider member (10) to the second position (P2) when the tube (5) is inserted, thereby restoring sealed engagement ofthe seal ring (8).

Description

Tube connector with leak detection Field of the invention The present invention relates to a tube connector in particular a push-fit tube connector with leak detection for indicating correct insertion of a tube into the tube connector. Background art European patent application EP 1 039 204 A2 discloses a push-fit connector for use as an attachment to connect two pipes. The connector comprises at least one hollow connecting portion adapted to receive, when the connector is in use, a pipe through an opening at an end of the connecting portion comprising an outer tubular body containing connection means comprising a grab ring to engage and resist removal of the inserted pipe inserted through the opening into the connector. The grab ring has gripping teeth at its inner periphery which grip into a wall of the inserted pipe to resist its withdrawal from the connector. The connecting portion further comprises a seal ring for, when the connector is in use, sealed engagement around a pipe wall of the inserted pipe preventing passage of fluid from the pipe out of the connector.

Even though push-fit pipe connectors of the type described above are easy to use by an installer without any specialized tools, in practice it is often difficult to ascertain whether a pipe has been properly inserted for providing a reliable fluid tight seal between the inserted pipe and the connector.

Summary of the invention The present invention seeks to provide an improved tube connector, in particular a tube connector of the push-fit or push-in type, wherein the tube connector is easy to use without specialized tools and which provides feedback as to whether a tube has been properly inserted into the connector for achieving a reliable fluid tight seal between the tube and the tube connector. The tube connector of the present invention is particularly advantageous for tubes carrying a fluid such as a gas, e.g. natural gas.

According to the present invention, the tube connector comprises for push-fit connection to a tube, i.e. a push-fit tube connector, comprising a hollow connecting body having a channel with open end configured to receive a tube being inserted into the connecting body; a grab ring arranged in the channel and configured for clamping engagement on a circumferential outer surface of the tube to prevent removal thereof from the connecting body when the tube connector is in use; a resilient seal ring arranged in the channel configured for sealing engagement on a circumferential inner sealing surface of the channel and on the circumferential outer surface of the tube when the connecter is in use; further comprising an elongated slider member longitudinally arranged in the channel and longitudinally movable with respect thereto between a first position and a second position, wherein the slider 40 member comprises a prong end and an opposing hook end,

wherein the prong end is in a wedged position between the seal ring and the circumferential inner sealing surface of the channel in the first position of the slider member when the tube connector is not in use, and wherein the hook end comprises an abutment face configured to engage a circumferential end face of the tube when the tube is inserted into the channel for moving the slider member from the first position toward the second position, wherein the prong end is in an unwedged position with respect to the seal ring and the circumferential inner sealing surface of the channel in the second position of the slider member when the tube connector is in use.

According to the invention, providing clear and reliable feedback for an incorrectly installed push-fit tube connector may be achieved by deliberately causing a strongly leaking tube connector when a tube is or remains incorrectly installed. Such a deliberately leaking tube connector is provided by the tube connector as claimed, and in particular by the sliding member of which the prong end is in a wedged position between the seal ring and the circumferential inner sealing surface of the channel in the first position of the slider member when the tube connector is not in use. Because the prong member is wedged between the seal ring and the circumferential inner sealing surface in the first position of the slider member, a mere partial circumferential seal is obtained as substantial gaps are present on both sides of the prong member as the seal ring will not exactly follow contours of the prong member. Therefore, in the first position, the prong member causes a dislocation of the seal ring and as such denies a circumferential seal by the seal ring.

Only by sufficiently deep insertion of a tube is it possible to push the slider member further into the channel toward the second position such that the prong member is in the unwedged position with respect to the seal ring and the circumferential inner sealing surface of the channel.

Note that in the unwedged position, the prong member is longitudinally retracted away from the seal ring and the circumferential inner sealing surface, thereby allowing the resilient seal ring to completely engage the circumferential inner sealing surface for a complete circumferential seal thus blocking passage of a fluid from the connecting body.

Short description of drawings The present invention will be discussed in more detail below, with reference to the attached drawings, in which Figure 1 shows a cross section of a tube connector with a partially inserted tube according to an embodiment of the present invention; Figure 2 shows a cross section of a tube connector with a fully inserted tube according to an embodiment of the present invention; Figure 3 shows a three dimensional view of a slider member according to an embodiment of the present invention; Figure 4 shows a three dimensional view of a slider member arranged in a channel 40 groove according to an embodiment of the present invention;

Figure 5 shows a cross section of a tube connector with a fully inserted tube according to another embodiment of the present invention; Figure 6 shows a three dimensional view of a grab ring according to an embodiment of the present invention; and wherein Figure 7 shows a cross section of a grab ring according to an embodiment of the present invention. Detailed description of embodiments Figure 1 and 2 each show a cross section of a tube connector 1 of the push-fit type with a partially and fully inserted tube 5, respectively, according to an embodiment of the present invention. In the embodiments shown, the tube connector 1 comprises a hollow connecting body 2 having a channel 3, e.g. round/cylindrical channel, with open end 4 configured to receive a tube 5 for insertion into the connecting body 2, i.e. the channel 3. The channel 3 comprises an inner diameter D; and the tube 5 has an outer diameter Ds, where it is understood that the inner diameter Di is larger than the outer diameter D, to allow smooth insertion of the tube 5 in the channel 3.

A grab ring 8 is arranged in the channel 3 and configured for clamping engagement on a circumferential outer surface 7 of the tube 5 to prevent removal thereof from the connecting body 2 when the tube connector 1 is in use. In an exemplary embodiment, the grab ring 6 is in wedged engagement with the connecting body 2 such that a pull force on the tube 5 increases the clamping engagement resisting removal of the tube 5 from the connecting body 2.

The tube connector 1 further comprises a resilient seal ring 8 arranged in the channel 3 and wherein the seal ring 8 is configured for sealing engagement on a circumferential inner sealing surface 9 of the channel 3 and on the circumferential outer surface 7 of the inserted tube

5. In an exemplary embodiment, the seal ring 8 may have a substantially circular cross section with radius “R”. In further embodiments the seal ring 8 is a resilient O-ring of e.g. elastomeric material, e.g. (Hydrogenated) Nitrile Butadiene Rubber, (H)NBR, which is advantageous for (natural) gas applications.

Further, an elongated slider member 10 is provided and longitudinally arranged in the channel 3 and longitudinally movable with respect thereto between a first position P1 and a second position P2. The slider member 10 as shown comprises a prong end 11 and an opposing hook end 12.

Note that terms such as “longitudinal”, “longitudinally” etc. refer to a direction parallel to a longitudinal or lengthwise axis “O” of the connecting body 2 as depicted in the figures. The terms “longitudinal” and “lengthwise” may be considered equivalent. Also, it is emphasized that the term “tube” may also be interpreted as “pipe” or even a “hose”, so the present invention equivalently relates to a push-fit pipe connector or hose pipe connector. The words “tube”, “pipe” or “hose” are not meant to convey any specific level of structural stiffness, so the tube 5 may be substantially rigid or may also exhibit various levels of flexibility depending on the application. Moreover, theterm “connector” is considered the same as “coupling” or “fitting”, so the present invention relates to a tube connector, a tube coupling or a tube fitting of the push-fit type.

The prong end 11 of the slider member 10 is in a longitudinally wedged position, i.e. wedged in longitudinal direction, between the seal ring 8 and the circumferential inner sealing surface 9 of the channel 3 in the first position P1 of the slider member 10 when the tube connector is not in use 1. For now, the prong end 11 may be envisaged as a thin, longitudinally pointed part of the slider member 10.

The hook end 12 of the slider member 10 comprises an abutment face 13 configured to engage a circumferential end face 14 of the tube 5 when the tube 5 is inserted into the channel 3, as indicated by the arrow “I”, such that the slider member 10 is moved from the first position P1 to the second position P2. Note that the first position P1 corresponds to a configuration of the tube connector 1 when it is not (yet) in use, e.g. when it is ready to be used by an installer for the first time.

As Figure 2 suggests, the second position P2 corresponds to a configuration of the tube connector 1 when the tube 5 has been inserted deep enough, e.g. to a deepest possible insertion depth in the channel 3 when the tube 5 cannot be pushed any deeper into the connecting body 2. Figure 2 further shows that, in the second position P2, the prong end 11 is in a longitudinally unwedged position with respect to the seal ring 8 and the circumferential inner sealing surface 9 of the channel 3. That is, in the second position P2 of the slider member 10, the prong end 11 is in a longitudinally retracted position away from the seal ring 8 and the circumferential inner sealing surface 9 of the channel 3.

According to the present invention, clear and reliable feedback for an incorrectly installed push-fit tube connector may be achieved by deliberately causing/maintaining a strongly leaking tube connector 1 when a tube 5 is incorrectly installed. Such deliberate leakage of the tube connector 1 is achieved by the tube connector 1 as described above, particularly by the sliding member 10 wherein the prong end 11 remains in a wedged position between the seal ring 8 and the circumferential inner sealing surface 9 of the channel 3 as long as the slider member 10 has not reached the second position P2.

When the prong member 11 is in a wedged configuration between the seal ring 8 and the circumferential inner sealing surface 9 in the first position P1 of the slider member 10, a mere partial circumferential seal is obtained along the circumferential inner sealing surface 9 as substantial gaps are present (not shown) on both sides of the prong member 11. These gaps are caused by the fact that, even though the seal ring 8 is resilient, the seal ring 8 will not be able to accurately follow the complete contour of the prong member 11 along the circumferential inner sealing surface 9 when the seal ring 8 is forced to extend over the prong member 11.

Only by sufficiently deep insertion of the tube 5 such that the second position P2 of the slider member 10 is reached allows movement of the prong member 11 toward the unwedged/retracted position with respect to the seal ring 8 and the circumferential inner sealing surface 9 of the channel 3.

The unwedged/retracted position of the prong member 11 corresponds to a longitudinally retracted position away from the seal ring 8 and the circumferential inner sealing surface 9 wherein the resilient seal ring 8 is able to completely engage the circumferential inner sealing surface 9 for blocking passage of fluid (gas or liquid) from the tube 5 and the connecting body 2 5 when the tube connector 1 is properly installed.

So as depicted in Figure 1, in the first position P1 of the slider member 10 the prong end 11 pushes/separates the seal ring 8 away from the circumferential inner sealing surface 9 so that the seal ring 8 exhibits a deformed radius Rd as a result of which gaps are created that allow passage of fluid, hence causing a deliberate leak of the tube connector 1. From Figure 2 it is seen that in the second position P2 of the slider member 10 the prong end 11 is in the aforementioned unwedged or retracted position as a result of which the seal ring 8 is able to achieve full circumferential engagement with the circumferential inner sealing surface 9 and a such provide a reliable fluid tight seal.

In an embodiment, the connecting body 2 and the slider member 10 are made from a plastic material, thereby increasing durability of the tube connector 1 and keeping weight and manufacturing costs down.

With further regard to the slider member 10, Figure 3 shows a detailed three dimensional view of a slider member 10 and Figure 4 shows a three dimensional view of a slider member 10 arranged in the channel according to embodiments of the present invention.

In the embodiments shown, the channel 3 of the connecting body 2 may comprise an inner channel surface 15 provided with a longitudinal channel groove 16 having a predetermined groove depth Dg and wherein the slider member 10 is moveably arranged in the channel groove 18. By using the channel groove 16 it is possible to allow the tube 5 and the slider member 10 to be arranged side- by-side in the connecting body 2 without interference.

In an embodiment, the channel groove 16 has an upper groove portion 17 and a lower groove portion 18, wherein the upper groove portion 17 is narrower than the lower groove portion 18, and wherein the slider member 10 has an upper slider portion 198 (longitudinally) extending through the upper groove portion 17 and a lower slider portion 20 (longitudinally) extending through the lower groove portion 18, wherein the upper slider portion 19 is thinner than the lower slider portion 20. So in this embodiment the upper groove portion 17 has an upper groove width Wu which is smaller than a lower groove width WL of the lower groove portion 18, and wherein the upper slider portion 19 has an upper slider thickness Tu which is smaller than a lower slider thickness TL of the lower slider portion 20. In this embodiment the slider member 10 is longitudinally moveable, e.g. slidable, through the channel groove 16 but wherein radial movement of the slider member 10 is prevented as the thicker lower slider portion 20 snugly but loosely fits in the wider lower groove portion 18. In this way the slider member 10 will not radially dislocate or rotate when moved by a force on the abutment face 13 of the hook end 12. In an advantageous embodiment, the hook end 12 of the slider member 10 has a hook height Hi which is larger than the groove depth Dg of the channel groove 16. In this embodiment 40 the hook end 12 protrudes radially inward beyond the inner channel surface 15 allowing the hookend 12 to be caught/engaged by the circumferential end face 14 of the tube 5 when the tube 5 is inserted into the connecting body 2.

In an embodiment, the slider member 10 further comprises an intermediate slider part 21 extending between the hook end 12 and the prong end 11, wherein the intermediate slider part 21 has an intermediate height Hz equal to or smaller than the groove depth Ds. In this embodiment the intermediate slider part 21 is thus fully received within the channel groove 16 and as such cannot interfere with the tube 5 as it is inserted into the channel 3. The intermediate slider part 21 may further provide increased stiffness to the slider member 10 such that deformation (e.g. bending) is minimized when the slider member 10 is being moved through the channel groove 16.

In an advantageous embodiment, the prong end 11 longitudinally projects from the intermediate slider part 21 and has a prong length Le equal to or larger than the radius R of the seal ring 8. As can be inferred from Figure 1 and 2, in order to provide for the longitudinally wedged position of the prong end 11 between the seal ring 8 and the circumferential inner sealing surface 9 in the first position P1, it is advantageous that the prong length Lp is at least equal to the radius R of the seal ring 8. This allows the prong end 11 to at least reach an engagement point Ps (see Figure 2) of the seal ring 8 at which the seal ring 8 would touch the circumferential inner sealing surface 9 to achieve sealed engagement. The prong end 11 is then able to adequately extend underneath the seal ring 8 and locally push/separate the seal ring 8 away from the circumferential inner sealing surface 9 for creating leakage through the aforementioned gaps.

In an advantageous embodiment, the prong end 11 has a prong height or thickness Hp equal to or smaller than half of the radius (e.g. R/2) of the seal ring 8. This embodiment provides a sufficiently deformed radius Rd of the seal ring 8 when the prong end 11 is in the wedged position between the seal ring 8 and the circumferential inner sealing surface 9 to achieve a leaking tube connector 1.

From the Figure 1 to 4 it is readily observed that the prong end 11 may be seen as a longitudinally extending/projecting thin needle part of the slider member 10 compared to the height H2 of the intermediate slider part 21. Then to prevent breaking the prong end 11 from the intermediate slider part 21 and to minimize bending stresses where the prong end 11 attaches to the intermediate slider part 21, an embodiment is provided wherein a tapered connection “S” is provided between the prong end 11 and the intermediate slider part 21. In a further embodiment the tapered connection S may be shaped in conformal fashion, e.g. having a similar radius, with respect to the seal ring 8, so that the prong end 11 can be as short as possible yet allow for the longitudinally wedged position/engagement between the seal ring 8 and the circumferential inner sealing surface 9 to be obtained in the first position P1.

As mentioned earlier, in the second position P2 of the slider member 10, the prong end 11 is in the longitudinally unwedged position with respect to the seal ring 8 and the circumferential inner sealing surface 9, i.e. in a retracted position away from the seal ring 8 and the circumferential inner sealing surface 9. This allows the seal ring 8 to engage the circumferential inner sealing surface 9 completely for providing a fluid tight seal.

In order to ensure that the prong end 11 is indeed sufficiently retracted away from the seal ring 8 when the slider member 10 is in the second position P2, an embodiment is provided wherein a tip distance L between the abutment face 13 of the hook end 12 and a prong tip K of the prong end 11 is smaller than a seal distance Q between the seal ring 8 and the abutment face 13 of the hook end 12 at the second position P2 of the slider member 10. In this embodiment, see e.g.

Figure 2, the seal distance Q may be taken from a side of the seal ring 8 which his longitudinally most proximal to the abutment face 13 when the slider member 10 is in the second position P2. It is noted that depending on the prong height or thickness He, it is possible to achieve the longitudinally unwedged position of the prong end 11 as long as the prong tip K does not come into contact with the seal ring 8. That is, given a second position P2 of the slider member 10, then a longitudinal separation distance Z can be defined between the seal ring 8 and the prong tip K as shown in Figure 2. The separation distance Z may be viewed as the distance between the depicted engagement point Ps of the seal ring 8 and the prong tip K.

So as long as the separation distance Z in the second position P2 of the slider member 10 does not lead to contact engagement between the prong end 11 and the seal ring 8, then a longitudinally unwedged position of the prong end 11 is achieved in the second position P2. From this it is readily inferred that the longitudinal separation distance Z yielding an unwedged position/configuration of the prong end 11 depends on the prong height He, wherein the separation distance Z must increase for a higher prong height He to avoid contact between the prong end 11 and the seal ring 8, whilst the separation distance Z can decrease for a smaller prong heights He.

Referring to Figure 1 and 2 it is seen that the tube 5 may be inserted into the channel 3 so that the slider member 10 can be moved from the first position P1 as shown in Figure 1 to the second position P2 of Figure 2, thereby undoing the wedged position/engagement of the prong end 11 with respect to the seal ring 8 and the circumferential inner sealing surface 9. Due to the resiliency of the seal ring 8, a complete circumferential sealed engagement is achieved between the seal ring 8 and the circumferential inner sealing surface 9 once the prong member 11 is retracted away from underneath the seal ring 8. Note that when the longitudinally unwedged position of the prong end 11 is achieved, the tube 5 need not be inserted any further and further tube insertion may be blocked once the second position P2 of the slider member 10 has been reached.

To limit further insertion of the tube 5 at the second position P2 of the slider member 10, the channel 3 of the connecting body 2 is provided with a channel abutment face 22 extending between two inner channel surfaces 15, 23 of the channel 3 with different diameters Di, Db, wherein the channel abutment face 22 is configured to engage the circumferential end face 14 of the tube 5 when the slider member 10 is in the second position P2, thereby blocking further insertion of the tube into the channel 3 of the connecting body 2. In this embodiment, the channel abutment face 22 defines a transition face/surface between the two inner channel surfaces 15, 23 40 of the channel 3 with different inner diameters Di, Db, wherein the depicted diameter Db may beseen defined as a tube “blocking” diameter. Note that in this embodiment the channel abutment face 22 extends between the inner channel surface 15 with inner diameter Di and a further inner channel surface 23 of the channel 3 with further inner (blocking) diameter Db. In an exemplary embodiment as shown in Figure 1 and 2, the inner diameter Di of the inner channel surface 15 is larger than the further inner diameter Db of the further inner channel surface 23. By taking the outer diameter Do of the tube 5 larger than the further inner diameter Db causes the circumferential end face 14 of the tube 5 to engage the channel abutment face 22 when the slider member 10 is in the second position P2, thereby blocking further insertion of the tube 5. In an embodiment, the channel abutment face 22 may be a straight face substantially perpendicular to the longitudinal axis O of the connecting body 2. In an alternative embodiment as depicted Figures 1 and 2, the channel abutment face 22 is a bevelled channel abutment face, i.e. arranged at an angle between 0° and 90° degrees with respect to the longitudinal axis O of the connecting body 2. The channel abutment face 22 may be used to further increase safe and reliable operation of the tube connecter 1. For example, the tube connector 1 may be adapted to deny a fluid tight seal when the circumferential end face 14 of an inserted tube 5 does not have a required geometry.

For example, Figure 1 and 2 each show an embodiment of a tube 5 that comprises an inner support sleeve 24 extending through an end part 25 of the tube 5 inserted in the connecting body 2. The inner support sleeve 24 may be advantageous to prevent a collapse of the tube 5 as the seal ring 8 and the grab ring 6 could impose a large circumferential clamping force onto the tube 5 which it may not withstand for extended periods of time. By providing the tube 5, e.g. its end part 25, with an inner support sleeve/bush 24 allows such a collapse of the tube 5 to be prevented. For example, a tube 5 made of plastic material, e.g. polyethylene (PE), may benefit from using such an inner support bush/sleeve 24 as the plastic tube 5 could be too weak and/or flexible.

As a further advantage, the inner support sleeve 24 may be used to provide a circumferential end face 14 to the tube 5 with a particular geometry for allowing the second position P2 of the slider member 10 to be reached. The tube connecter 1 may therefore be adapted to only allow for a particular circumferential end face 14 for moving the slider member 10 to the second position P2 when the tube 5 is inserted.

In the exemplary embodiments shown in Figure 1 and 2, the tube 5 comprises a inner support sleeve 24 providing a circumferential end face 14 having a bevelled end face portion 26 for engagement with a bevelled channel abutment face 22 as mentioned earlier. This bevelled end face portion 26 is adapted for conformal engagement with the bevelled channel abutment face 22, thereby blocking further insertion of the tube 5 yet allow the slider member 10 to reach the second position P2 for obtaining the unwedged/retracted position of the prong member 11.

In addition to the bevelled end face portion 26 of the circumferential end face 14, the circumferential end face 14 of the inner support sleeve 24 may further comprise a forward 40 protruding end face portion 27 substantially perpendicular to the longitudinal axis O. From Figure

2 it is seen that as the tube 5 is inserted in the connecting body 2, the forward protruding end face portion 27 engages the abutment face 13 of the hook end 12 and as such allow the slider member 10 to reach the second positioned P2. Most notably, the forward protruding end face portion 27 protrudes into a deeper part of the channel 3 with the further inner diameter Db which is smaller than the outer diameter Do of the tube 5. This allows the tube connecter 1 to deliberately leak when the tube 5 does not comprise the inner support sleeve 24.

In view of the inner support sleeve/bush 24, a further aspect of the present invention relates to a combination of the tube connector 1 and the inner support sleeve 24, wherein the inner support sleeve 24 is configured for insertion into an end part 25 of a tube 5, wherein the end part 25 of the tube 5 is receivable in the channel 3 of the connecting body 2 of the tube connector

1. The inner support sleeve 24 then provides the circumferential end face 14 to the tube 5 for engagement with the abutment face 13 of the hook end 12 of the slider member 10. This combination then ensures that the tube connector 1 is properly installed without leakage as only the inner support sleeve 24 in the tube 5 is specifically adapted to allow the slider member 10 to be fully moved toward the second position P2, i.e. the position in which the prong end 11 is in the longitudinally unwedged position with respect to the seal ring 8 and the circumferential inner sealing surface 9 for achieving a properly sealed tube connector 1 when in use.

In an embodiment of the combination, the circumferential end face 14 may comprise the forward protruding end face portion 27 as mentioned earlier, which is then specifically adapted for engagement with the abutment face 13. This prevents that a tube 5 without the inner support sleeve 24 cannot fully move the slider member 10 toward the second position P2, thus maintaining a leaking tube connector 1 as the tube 5 will not be properly installed.

In a further embodiment of the combination, the circumferential end face 14 may be further provided with the bevelled end face portion 26 for engagement with the bevelled channel abutment face 22. This bevelled end face portion 26 of the inner support sleeve 24 is then adapted for conformal engagement with the bevelled channel abutment face 22, thereby blocking further insertion of the tube 5 yet allowing the slider member 10 to be pushed to the second position P2 for achieving the unwedged/retracted position of the prong member 11 by virtue of the forward protruding end face portion 27.

Figure 5 shows an example wherein the tube connector 1 can prevent leak free operation, i.e. causing leakage, when a tube 5 is inserted which is not provided with a required circumferential end face 14 for moving the slider member 10 to the second position P2. As shown, the tube 5, without the inner support sleeve 24, is inserted into the channel 3 at a maximum inserted depth X at which the inner diameter Di of the inner channel surface 15 of the channel 3 changes to a smaller further inner diameter Db of the further inner channel surface 23. However, at the maximum inserted depth X, the slider member 10 is at an intermediate position Py and has not yet reached the second position P2 for retracting the prong end 11 from underneath the seal ring 8. Therefore, by providing the tube 5 with the inner support sleeve 24, the circumferential end face 14 of the inner support sleeve 24 is able to move the slider member 10 toward the second 40 position P2.

From the above it is clear that a length of the hook end Lu (see Figure 3) and/or a longitudinal length of the channel groove 16 in conjunction with the tip distance L can be used to determine the second position P2 at which the prong end 11 is in the unwedged/retracted position.

The tube connector 1 of the present invention should be safe to use, particularly for natural gas application, and as such the grab ring 6 plays an important role to maintain insertion of the tube 5 when it is subjected to a pulling force. To that end the grab ring 6 is provided with features that facilitate safe and reliable operation of the tube connector 1 when in use.

Figure 6 and 7 show a three dimensional view and a cross section, respectively, of a grab ring 6 according to an embodiment of the present invention. As depicted, the grab ring 6 comprises a circumferential conical outer surface 28 configured for wedged engagement with a corresponding circumferential conical inner surface 29 of the channel 3 of the connecting body 2. The grab ring 6 is further provided with a plurality of circumferentially arranged resilient spring plates 30 each of which comprises an outward facing surface 31, configured for resilient (wedged) engagement with the circumferential conical inner surface 29 of the channel 3, and an opposing inward facing surface 32 provided with one of more grabbing teeth 33 for engagement on the circumferential outer surface 7 of the tube 5 when the tube connector 1 is in use. In this embodiment the one or more grabbing teeth 33 grab into the tube 5 as the outward facing surface 31 of the spring plate 30 resiliently engages the circumferential conical inner surface 29. In case the tube 5 is subjected to a pull force, the outward facing surface 31 of each resilient spring plate 30 engages the circumferential conical inner surface 29 more strongly, which in turn increases the grabbing force of the one or more grabbing teeth 33.

It is important to note that the outward facing surface 31 of each resilient spring plate 30 engages the circumferential conical inner surface 29 of the channel 3 independently from the circumferential conical outer surface 28 of the grab ring 6. This allows the spring plates 30 to grab onto the tube 5 with a locally higher force than the grab ring 6 itself.

With reference to Figure 7, in an embodiment each resilient spring plate 30 is a U-shaped spring plate 30 extending in longitudinally direction (see longitudinal axis O) of the grab ring 6 and wherein each U-shaped spring plate 30 has an open end 34 that connects to or engages the grab ring 8. The U-shape of each spring plate 30 provides radial resiliency in the radial direction Y as depicted. The resilient behaviour of each U-shaped spring plate 30 is achieved as each U-shaped spring plate 30 comprises an outward leg 35 and inward leg 36, wherein the outward leg 35 comprises the outward facing surface 31 and wherein the inward leg 36 comprises the inward facing surface 32 provided with the one of more grabbing teeth 33.

When the outward facing surface 31 of the outward leg 35 engages the circumferential conical inner surface 29 of the channel 3, and the one or more grabbing teeth 33 of the inward leg 36 engage the circumferential outer surface 7 of the tube 5, then the outward leg 35 and inward leg 36 are pushed together. As the outward and inward legs 35, 36 are pushed together, opposing forces onto the circumferential conical inner surface 29 and the circumferential outer surface 7 aregenerated. As depicted, in an embodiment the outward facing surface 31 of each U-shaped spring plate 30 may be a convex outward facing surface 31.

In an advantageous embodiment, the open end 34 of each U-shaped spring plate 30 may be pivotally connected to the grab ring 6, so that each spring plate 30 is able to rotate for improved alignment of the inward leg 36, particularly the inward facing surface 32 with grabbing teeth 33, with respect to the circumferential outer surface 7 of the tube 5.

In an embodiment, each resilient U-shaped spring plate 30 extends around a longitudinally extending grab ring portion 37, e.g. a substantially straight longitudinally extending grab ring portion 37, such that the U-shaped spring plate 30 remains connected to the grab ring 6 and kept in place when the tube connector 1 is not (yet) in use.

In view of the above, the present invention can now be summarized by the following embodiments: Embodiment 1. A tube connector (coupling/fitting) for push-fit connection to a tube, comprising a hollow connecting body (2) provided with a channel (3) having an open end (4) configured to receive a tube (5) being inserted into the connecting body (2); a grab ring (6) arranged in the channel (3) and configured for clamping engagement on a circumferential outer surface (7) of the tube (5) to prevent removal thereof from the connecting body (2) when the tube connector (1) is in use; a resilient seal ring (8) arranged in the channel (3) configured for sealing engagement on a circumferential inner sealing surface (9) of the channel (3) and on the circumferential outer surface (7) of the tube (5); further comprising an elongated slider member (10) longitudinally arranged in the channel (3) and longitudinally movable with respect thereto between a first position (P1) and a second position (P2), wherein the slider member (10) comprises a prong end (11) and an opposing hook end (12), wherein the prong end (11) is in a longitudinally wedged position between the seal ring (8) and the circumferential inner sealing surface (9) of the channel (3) in the first position (P1) of the slider member (10), and wherein the hook end (12) comprises an abutment face (13) configured to engage a circumferential end face (14) of the tube (5) when the tube (5) is inserted into the channel (3) for moving the slider member (10) from the first position (P1) toward the second position (P2), wherein the prong end (11) is in a longitudinally unwedged/retracted position with respect to the seal ring (8) and the circumferential inner sealing surface (9) of the channel (3) in the second position (P2) of the slider member (10).

Embodiment 2. The tube connector according to embodiment 1, wherein the channel (3) of the connecting body (2) comprises an inner channel surface (15) provided with a longitudinal channel groove (16) with a predetermined groove depth (Dg) in which the slider member (10) is moveably arranged.

40

Embodiment 3. The tube connector according to embodiment 2, wherein the channel groove (18) has an upper groove portion (17) and a lower groove portion (18), wherein the upper groove portion (17) is narrower than the lower groove portion (18), and wherein the slider member (10) has an upper slider portion (19) extending through the upper groove portion (17) and a lower slider portion (20) extending through the lower groove portion (18), wherein the upper slider portion (19) is thinner than the lower slider portion (20). Embodiment 4. The tube connector according to embodiment 2 or 3, wherein the hook end (12) of the slider member (10) has a hook height (H1) larger than the groove depth (Dg) .

Embodiment 5. The tube connector according to any of embodiments 2-4, wherein the slider member (10) further comprises an intermediate slider part (21) extending between the hook end (12) and the prong end (11), wherein the intermediate slider part (21) has a height (H2) equal to or smaller than the groove depth (Dg).

Embodiment 6. The tube connector according to embodiment 5, wherein the prong end (11) longitudinally projects from the intermediate slider part (21) and has a prong length (LP) equal to or larger than a radius (R) of the seal ring (8).

Embodiment 7. The tube connector according to embodiment 6, wherein the prong end (11) has a prong height (HP) equal or smaller than half of the radius (R) of the seal ring (8). Embodiment 8. The tube connector according to any of embodiments 5-7, wherein an tapered connection (8S) is provided between the prong end (11) and the intermedia slider part (21).

Embodiment 9. The tube connector according to any of embodiments 1-8, wherein a tip distance (L) between the abutment face (13) of the hook end (12) and a prong tip (K) of the prong end (11) is smaller than a seal distance (Q) between the seal ring (8) and the abutment face (13) of the hook end (12) at the second position (P2) of the slider member (10).

Embodiment 10. The tube connector according to any of embodiments 1-9, wherein the channel (3) of the connecting body (2) is provided with a channel abutment face (22) extending between two inner channel surfaces (15, 23) of the channel (3) with different inner diameters (Di, Db), wherein the channel abutment face (22) is configured to engage the circumferential end face (14) of the tube (5) when the slider member (10) is in the second position (P2). Embodiment 11. The tube connector according to embodiment 10, wherein the channel abutment face (22) is a bevelled channel abutment face.

Embodiment 12. The tube connector according to any of embodiments 1-11, wherein the grab ring (6) comprises a circumferential conical outer surface (28) configured for wedged engagement with a corresponding circumferential conical inner surface (29) of the channel (3) of the connecting body (2), wherein the grab ring (6) is provided with a plurality of circumferentially arranged resilient spring plates (30) each of which comprises an outward facing surface (31) configured for resilient engagement with the circumferential conical inner surface (29) of the channel (3), and an opposing inward facing surface (32) provided with one of more grabbing teeth (33) for engagement on the circumferential outer surface (7) of the tube (5) when the tube connector (1) is in use.

Embodiment 13. The tube connector according embodiment 12, wherein each resilient spring plate (30) is a U-shaped spring plate (30) extending in longitudinally direction of the grab ring (6) and wherein each U-shaped spring plate (30) has an open end (34) connecting to the grab ring (8).

Embodiment 14. The tube connector according to embodiment 13, wherein each resilient U- shaped spring plate (30) extends around a longitudinally extending grab ring portion (37).

Embodiment 15. The tube connector according to any of embodiments 1-14, wherein the connecting body (2) and the slider member (10) are made from a plastic material.

Embodiment 16. A combination of a tube connector (1) according to any of embodiments 1-15 and an inner support sleeve (24), the inner support sleeve (24) being configured for insertion into an end part (25) of a tube (5), wherein the end part (25) of the tube (5) is receivable in the channel (3) of the connecting body (2) of the tube connector (1), wherein the inner support sleeve (24) provides a circumferential end face (14) to the tube (5) for engagement with the abutment face (13) of the hook end (12) of the slider member (10).

Embodiment 17. The combination according to embodiment 16, wherein the circumferential end face (14) comprises a forward protruding end face portion (27) adapted for engagement with the abutment face (13).

The present invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.

Claims

CONCLUSIESCONCLUSIONS

1. Een buiskoppeling voor insteekverbinding met een buis, omvattend een hol verbindingslichaam (2) voorzien van een kanaal (3) met een open einde (4) dat is ingericht voor opname van een buis (5) die in het verbindingslichaam (2) wordt gestoken; een grijpring (6) die is aangebracht in het kanaal (3) en is ingericht voor klemmende aangrijping op een omlopend buitenoppervlak (7) van de buis (5) om verwijdering daarvan uit het verbindingslichaam {2) te voorkomen wanneer de buiskoppeling (1) in gebruik is; een veerkrachtige afdichtingsring (8) die is aangebracht in het kanaal (3) en is ingericht voor afdichtende aangrijping op een omlopend inwendig afdichtoppervlak (9) van het kanaal (3) en een omlopend uitwendig afdichtoppervlak (7) van de buis (5); verder omvattend een langwerpig schuifelement (10) dat in longitudinale richting in het kanaal (3) is aangebracht en longitudinaal beweegbaar is ten opzichte daarvan tussen een eerste positie (P1) en een tweede positie (P2), waarbij het schuifelement (10) een vorkuiteinde (11) omvat en een tegenoverliggend haakuiteinde (12), waarbij het vorkuiteinde (11) zich in een longitudinaal ingeklemde positie bevindt tussen de afdichtingsring (8) en het omlopend inwendig afdichtoppervlak (9) van het kanaal (3) in de eerste positie (P1) van het schuifelement (10), en waarbij het haakuiteinde (12) een aanslagvlak (13) omvat dat is ingericht om aan te grijpen op een omtrekseindvlak (14) van de buis (5) wanneer de buis (5) in het kanaal (3) wordt ingebracht voor het verplaatsen van het schuifelement (10) van de eerste positie (P1) naar de tweede positie (P2), waarbij het vorkuiteinde (11) zich in een longitudinaal teruggetrokken positie bevindt ten opzichte van de afdichtingsring (8) en het omlopend inwendig afdichtoppervlak (9) van het kanaal (3) in de tweede positie (P2) van het schuifelement (10).A pipe coupling for plug-in connection with a pipe, comprising a hollow connecting body (2) provided with a channel (3) with an open end (4) adapted to receive a pipe (5) being inserted into the connecting body (2). stabbed; a gripping ring (6) disposed in the channel (3) and arranged for clamping engagement with a circumferential outer surface (7) of the pipe (5) to prevent removal thereof from the connecting body (2) when the pipe coupling (1) is in use; a resilient sealing ring (8) disposed in the channel (3) and adapted for sealing engagement with a circumferential internal sealing surface (9) of the channel (3) and a circumferential external sealing surface (7) of the tube (5); further comprising an elongated slider (10) disposed longitudinally in the channel (3) and movable longitudinally relative thereto between a first position (P1) and a second position (P2), the slider (10) having a fork end (11) comprises an opposite hook end (12), the fork end (11) being in a longitudinally clamped position between the sealing ring (8) and the circumferential internal sealing surface (9) of the channel (3) in the first position ( P1) of the slider (10), and wherein the hook end (12) includes a stop face (13) adapted to engage a peripheral end face (14) of the tube (5) when the tube (5) is in the channel (3) is inserted to move the slider (10) from the first position (P1) to the second position (P2), the fork end (11) being in a longitudinally retracted position with respect to the sealing ring (8) and it circumambulating internal sealing surface (9) of the channel (3) in the second position (P2) of the sliding element (10).

2. De buiskoppeling volgens conclusie 1, waarbij het kanaal (3) van het verbindingslichaam (2) een binnenste kanaaloppervlak (15) omvat voorzien van een longitudinale kanaalgroef (16) met een vooraf bepaalde groefdiepte (Dg) waarin het schuifelement (10) beweegbaar is aangebracht.The pipe coupling according to claim 1, wherein the channel (3) of the connecting body (2) comprises an inner channel surface (15) provided with a longitudinal channel groove (16) with a predetermined groove depth (Dg) in which the sliding element (10) is movable. is applied.

3. De buiskoppeling volgens conclusie 2, waarbij de kanaalgroef (16) een bovenste groefgedeelte (17) en een onderste groefgedeelte (18) heeft, waarbij het bovenste groefgedeelte (17) smaller is dan het onderste groefgedeelte (18), en waarbij het schuifelement (10) een bovenste schuifgedeelte (19) heeft dat zich uitstrekt door het bovenste groefgedeelte (17) en een onderste schuifgedeelte (20) dat zich uitstrekt door het onderste groefgedeelte (18), waarbij het bovenste schuifgedeelte (19) dunner is dan het onderste schuifgedeelte (20).The pipe coupling of claim 2, wherein the channel groove (16) has an upper groove portion (17) and a lower groove portion (18), the upper groove portion (17) being narrower than the lower groove portion (18), and wherein the sliding element (10) has an upper sliding portion (19) extending through the upper groove portion (17) and a lower sliding portion (20) extending through the lower groove portion (18), the upper sliding portion (19) being thinner than the lower sliding part (20).

4. De buiskoppeling volgens conclusie 2 of 3, waarbij het haakuiteinde (12) van het schuifelement (10) een haakhoogte (H1) heeft die groter is dan de groefdiepte (Dy).The pipe coupling according to claim 2 or 3, wherein the hook end (12) of the sliding element (10) has a hook height (H1) that is greater than the groove depth (Dy).

5. De buiskoppeling volgens één van de conclusies 2-4, waarbij het schuifelement (10) verder een tussengelegen schuifdeel (21) omvat dat zich uitstrekt tussen het haakuiteinde (12) en het vorkuiteinde (11), waarbij het tussengelegen schuifdeel (21) een hoogte (Hz) heeft die gelijk is aan of kleiner is dan de groefdiepte (Dy).The pipe coupling of any of claims 2-4, wherein the sliding member (10) further comprises an intermediate sliding member (21) extending between the hook end (12) and the fork end (11), wherein the intermediate sliding member (21) has a height (Hz) equal to or less than the groove depth (Dy).

6. De buiskoppeling volgens conclusie 5, waarbij het vorkuiteinde (11) longitudinaal uitsteekt vanaf het tussengelegen schuifdeel (21) en een vorklengte (Le) heeft die gelijk is aan of groter is dan een radius (R) van de afdichtingsring (8).The pipe coupling of claim 5, wherein the fork end (11) protrudes longitudinally from the intermediate slide member (21) and has a fork length (Le) equal to or greater than a radius (R) of the sealing ring (8).

7. De buiskoppeling volgens conclusie 8, waarbij het vorkuiteinde (11) een vorkhoogte (Hp) heeft die gelijk is aan of kleiner is dan de helft van de radius (R) van de afdichtingsring (8).The pipe coupling according to claim 8, wherein the fork end (11) has a fork height (Hp) equal to or less than half the radius (R) of the sealing ring (8).

8. De buiskoppeling volgens één van de conclusies 5-7, waarbij een taps toelopende verbinding (S) wordt verschaft tussen het vorkuiteinde (11) en het tussengelegen schuifdeel (21).The pipe coupling according to any one of claims 5-7, wherein a tapered connection (S) is provided between the fork end (11) and the intermediate slider (21).

9. De buiskoppeling volgens één van de conclusies 1-8, waarbij een tipafstand (L) tussen het aanslagvlak (13) van het haakuiteinde (12) en een vorkpunt (K) van het vorkuiteinde (11) kleiner is dan een afdichtingsafstand (Q) tussen de afdichtingsring (8) en het aanslagvlak (13) van het haakuiteinde (12) op de tweede positie (P2) van het schuifelement (10).The pipe coupling according to any one of claims 1-8, wherein a tip distance (L) between the stop face (13) of the hook end (12) and a fork tip (K) of the fork end (11) is less than a sealing distance (Q ) between the sealing ring (8) and the stop face (13) of the hook end (12) at the second position (P2) of the sliding element (10).

10. De buiskoppeling volgens één van de conclusies 1-9, waarbij het kanaal (3) van het verbindingslichaam (2) is voorzien van een kanaalaanslagvlak (22) dat zich uitstrekt tussen twee binnenste kanaaloppervlakken (15, 23) van het kanaal (3) met verschillende binnendiameters (Di, Db), waarbij het kanaalaanslagvlak (22) is ingericht om aan te grijpen op het omtrekseindvlak (14) van de buis (5) wanneer het schuifelement (10) zich in de tweede positie (P2) bevindt.The pipe coupling according to any one of claims 1-9, wherein the channel (3) of the connecting body (2) has a channel abutment surface (22) extending between two inner channel surfaces (15, 23) of the channel (3) ) of different inner diameters (Di, Db), wherein the channel stop face (22) is arranged to engage the peripheral end face (14) of the tube (5) when the slider (10) is in the second position (P2).

11. De buiskoppeling volgens conclusie 10, waarbij het kanaalaanslagvlak (22) een afgeschuind kanaalaanslagvlak is.The pipe coupling of claim 10, wherein the channel abutment surface (22) is a beveled channel abutment surface.

12. De buiskoppeling volgens één van de conclusies 1-11, waarbij de grijpring (6) een omlopend conisch buitenoppervlak (28) omvat dat is ingericht voor klemmende aangrijping op een overeenkomstig omlopend conisch binnenoppervlak (29) van het kanaal (3) van het verbindingslichaam (2), waarbij de grijpring (8) is voorzien van een veelvoud van omlopend opgestelde veerkrachtige veerplaten (30) die elk een naar buiten gekeerd oppervlak (31) omvatten die is ingericht voor veerkrachtige aangrijping op het omlopend conisch binnenoppervlak (29) van het kanaal (3), en een tegenoverliggend naar binnen gekeerd oppervlak (32) omvatten dat is voorzien van één of meer grijptanden (33) voor aangrijping op het omlopend buitenoppervlak (7} van de buis (5) wanneer de buiskoppeling (1) in gebruik is. 40The pipe coupling of any one of claims 1 to 11, wherein the gripping ring (6) comprises a circumferential conical outer surface (28) adapted for clamping engagement with a corresponding circumferential conical inner surface (29) of the channel (3) of the connector body (2), wherein the gripping ring (8) is provided with a plurality of circumferentially arranged resilient spring plates (30) each comprising an outwardly facing surface (31) adapted for resilient engagement with the circumferential conical inner surface (29) of the channel (3), and comprise an opposing inwardly facing surface (32) provided with one or more gripping teeth (33) for engaging the circumferential outer surface (7} of the tube (5) when the tube coupling (1) is in use 40

13. De buiskoppeling volgens conclusie 12, waarbij elke veerkrachtige veerplaat (30) een U- vormige veerplaat (30) is die zich uitstrekt in de longitudinale richting van de grijpring (6) en waarbij elke U-vormige veerplaat (30) een open einde (34) heeft die aansluit op de grijpring (6).The pipe coupling of claim 12, wherein each resilient spring plate (30) is a U-shaped spring plate (30) extending in the longitudinal direction of the gripping ring (6) and wherein each U-shaped spring plate (30) has an open end. (34) that connects to the grip ring (6).

14. De buiskoppeling volgens conclusie 13, waarbij elke veerkrachtige U-vormige veerplaat (30) zich uitstrekt rond een longitudinaal uitstrekkend grijpringgedeelte (37).The pipe coupling of claim 13, wherein each resilient U-shaped spring plate (30) extends around a longitudinally extending grip ring portion (37).

15. De buiskoppeling volgens één van de conclusies 1-14, waarbij het verbindingslichaam (2) en het schuifelement (10) van een kunststofmateriaal zijn gemaakt.The pipe coupling according to any one of claims 1-14, wherein the connecting body (2) and the sliding element (10) are made of a plastic material.

16. Een combinatie van een buiskoppeling (1) volgens één van de conclusies 1-15 en een binnenste steunbus (24), waarbij de binnenste steunbus (24) is ingericht om in een eindgedeelte (25) van een buis (5) te worden ingebracht, waarbij het eindgedeelte (25) van de buis (5) kan worden opgenomen in het kanaal (3) van het verbindingslichaam (2) van de buiskoppeling (1), en waarbij de binnenste steunbus (24) een omtrekseindvlak (14) aan de buis (5) verschaft voor aangrijping op het aanslagvlak (13) van het haakuiteinde (12) van het schuifelement (10).A combination of a pipe coupling (1) according to any one of claims 1 to 15 and an inner support sleeve (24), wherein the inner support sleeve (24) is adapted to become in an end portion (25) of a pipe (5). wherein the end portion (25) of the tube (5) can be received in the channel (3) of the connecting body (2) of the tube coupling (1), and wherein the inner support sleeve (24) has a circumferential end face (14). the tube (5) provided for engaging the stop face (13) of the hook end (12) of the slider (10).

17. De combinatie volgens conclusie 18, waarbij het omtrekseindvlak (14) een naar voren stekend eindvlakgedeelte (27) omvat dat is ingericht voor aangrijping op het aanslagvlak (13).The combination of claim 18, wherein the peripheral end face (14) includes a protruding end face portion (27) configured to engage the stop face (13).