WO2008000356A1

WO2008000356A1 - Connecting fitting

Info

Publication number: WO2008000356A1
Application number: PCT/EP2007/005252
Authority: WO
Inventors: Christopher Emmerich; Richard Sapper; Frank Habenicht
Original assignee: Rehau Ag + Co
Priority date: 2006-06-30
Filing date: 2007-06-14
Publication date: 2008-01-03
Also published as: DE202006010323U1

Abstract

The invention relates to a connecting fitting (4) which comprises at least one connecting piece (3) onto which a composite metal/plastic pipe (2) can be slid. A plastic holding ring (26) is snap-connected to the connecting fitting (4). The plastic holding ring (26) is also snap-connected to a compression sleeve (36) beyond which it radially projects. A peripheral engaging groove (24) of the connecting piece (3) is adapted to receive the plastic holding ring (26) and is delimited by a peripheral collar (27), onto which the plastic holding ring (26) is slid when snap-connected to the connecting piece (3), and by a peripheral abutment wall (28) against which the plastic holding ring (26) abuts when snap-connected. The invention is characterized in that the abutment wall (28) is axially set back, starting from a groove base (29) of the engaging groove (24) and broadening the engaging groove (24) beyond a step (30), to such an extent that, when the plastic holding ring (26) is snap-connected, a gap (s) remains between the holding ring and the set-back section of the abutment wall (28). The invention provides a connecting fitting (4) with an engaging collar of the holding ring whose dimensions are less critical.

Description

Anscblussfϊtting

The invention relates to a Anschlußfϊtting according to the preamble of claim 1.

Such a connection fitting is known from EP 0 728 979 A1.

The dimensioning of a locking collar of the retaining ring, with which this engages in the locking groove of the connecting piece, is critical in the known connection fitting. Either the retaining ring has a relatively large amount of play on the connecting piece, which impairs the connection security, or it can be locked in place only with difficulty.

It is therefore an object of the present invention, a connection fitting of the type mentioned in such a way that the dimensioning of a locking collar of the retaining ring is less critical.

The object is achieved by a connection fitting with the features specified in the characterizing part of claim 1.

It has been recognized according to the invention that a latching groove having a stop wall with a recessed portion leads to the possibility of pushing the plastic retaining ring beyond the width of the groove bottom when it is snapped onto the connecting piece in the direction of the opening. This is also called overpressure. As a result, even with specification of only a very small game or no play between the locking collar of the plastic retaining ring and the locking groove is possible to securely lock the plastic retaining ring on the connection piece. An extension ratio of the plastic retaining ring according to claim 2 leads to a compact and stable retaining ring.

An axial extension of the plastic retaining ring according to claim 3 makes possible an advantageously compact connection fitting in the axial direction.

Exemplary embodiments of the invention will be explained in more detail below with reference to the drawing. In this show:

1 is a perspective view of a fitting

Assembly assembly, of a metal-plastic composite pipe, only the portion is shown, which is inserted into a connection fitting, with a pressing jaw of a pressing tongs in a pressing position with still-pressed compression sleeve and still unpressed metal-plastic

Composite pipe;

2 shows an axial longitudinal section through the fitting

Mounting assembly according to Fig. 1;

FIG. 2a shows the fitting mounting assembly in a representation similar to FIG. 2, with the pressing jaw in press position with a pressed compression sleeve and pressed metal-plastic composite pipe; FIG.

Fig. 3 enlarges a detail III in Fig. 2;

Fig. 4 enlarges a detail IV in Fig. 2; 5 is a perspective view of a compression sleeve of the connection fitting;

FIG. 6 is a side view of the press sleeve of FIG. 5 shown in half; FIG.

Fig. 7 is a section along the line VII-VII in Fig. 6;

FIG. 8 is a section similar to FIG. 2 of another embodiment of a fitting assembly; FIG.

Fig. 9 enlarges a detail IX in Fig. 8;

FIG. 10 enlarges a side view of one of the two pressing jaws of a pressing tongs, not otherwise shown, with a viewing direction in the longitudinal direction of the fitting-mounting assembly; FIG. and

11 is a perspective view of the pressing jaw of FIG. 10th

With the aid of a fitting mounting assembly 1, of which Figs. 1 to 7 show a first embodiment, a safe and in particular pressure-tight connection of a metal-plastic composite (MKV) pipe 2 with a connecting piece 3 of a total of 4 designated Guaranteed connection fittings. The MKV pipe 2 forms a pipe connection together with the connection fitting 4. The MKV tube 2 is shown in the drawing only in the region of a portion which is inserted into the Anschlußfϊtting 4. Instead of a MKV tube 2, another type of tube may be used, in particular a solid plastic tube, which consist of a single layer or may be constructed in multiple layers. In the event of a multilayer solid plastic tube, the individual layers can be connected to one another via suitable adhesive layers.

On the side of the circumferential collar 12, which is not shown in the drawing, the connection fitting 4 can be continued, for example, mirror-symmetrically, so that there is a 180 l: l pipe connector. The connecting piece 3 may also have other continuation variants, so that, for example, a 90 ° corner connector, a T-piece, a threaded connection or the like is formed.

The MKV tube 2 is three-layered. An inner layer 5 of the MKV pipe 2, the wall thickness of which makes up most of the total wall thickness of the MKV pipe 2, is made of uncured plastic. The inner layer 5 may alternatively be made of crosslinked plastic. The inner layer 5 is surrounded by a metal layer 6, which may be made of aluminum, for example. Outside, the metal layer 6 is covered by a thin cover layer 7, which is also made of plastic. The cover layer 7 serves to protect the metal layer 6. The individual layers 5 to 7 are connected to each other by suitable adhesive layers. The MKV tube 2 has an outer diameter of 32 mm in the illustrated embodiment. Other embodiments may have other outer diameters, for example 16, 20 or 25 mm.

At a leading, pushed onto the connecting piece 3 end 8, the MKV tube 2 has an internally encircling conical chamfer wall 9. The latter includes with a longitudinal axis 10 of the MKV tube 2 in the region of the end 8 an angle of about 15 °. Other Fasenwand- angle α in the range between 5 ° and 20 ° are possible. The connecting piece 3 is made of metal, in particular brass. The connecting piece may alternatively be made of plastic, in particular by injection molding. The connecting piece 3 is shown in the drawing of a free inlet end 11 to a remote inlet circumferential collar 12. In an inlet section 13, which begins at the inlet end 11 and ends adjacent to the circumferential collar 12, the connecting piece 3 has an outer diameter which is slightly smaller than the inner diameter of the MKV tube 2 in the unpressed state. In the inlet section 13, the connecting piece 3 has a plurality of outer circumferential ribs 14, one of which is shown in detail in FIG. 9. The circumferential ribs 14 of the embodiment according to FIGS. 1 to 7 are constructed in the same way as the circumferential rib 14 shown in FIG. 9. The circumferential ribs 14 on the inlet side have an inlet ramp 15 for facilitating the pushing on of the MKV tube 2. Opposite the inlet ramp 15, the circumferential ribs 14 each have a sharp 90 ° angled rib edge 16th

Approximately in the middle in the inlet section 13, the connecting piece 3 has a circumferential receiving groove 17 with an axial extension A. In a groove base 18 of the receiving groove 17, a circumferential receiving portion 19 lowered in relation to the other groove base 18 is designed. In the receiving portion 19 an inserted into the receiving groove 17 O-ring 20 is held. The axial extent A of the receiving groove is approximately twice, in particular 1.7 times, as large as the diameter of the sealing ring 20. The outer diameter of the receiving portion 19 is slightly larger than the inner diameter of the O-ring seal 20, so that the O-ring 20 saturated in the receiving portion 19 on the connecting piece 3 is applied. The outer diameter of the other groove bottom 18 is significantly larger than the outer diameter of the receiving portion 19 and the inner diameter of the O-ring seal 20, so that a displacement of the O-ring seal 20th in the receiving groove 17 even in the presence of a directed to the other Nutgrund axial force on the O-ring 20 is hardly possible.

As an alternative to a stepped groove base 18 as in the embodiment according to FIG. 4, it is possible to design the groove base conically in such a way that the diameter of the groove becomes smaller towards the stop collar 12. The O-ring 20 has an inner diameter corresponding to the smallest outer diameter of such a conically tapered groove bottom. The circumference of such a conical groove base, which enlarges in the direction of the inlet end 11, is significantly larger than the inside diameter of the O-sealing ring 20, so that the O-sealing ring is held in the receiving groove 17 in an in-run manner.

The receiving groove 17 is axially bounded on both sides by receiving ribs 21, the outer diameter of which is as large as the outer diameter of the circumferential ribs 14. The intake-distant receiving rib 21 has, like the circumferential ribs 14, likewise a rib edge 16.

The receiving portion 19 is executed in a direction away from the inlet end 1 1 region of the groove bottom 18 of the receiving groove 17. The axial extent of the receiving portion 19 is about as large as the diameter of the sealing ring 20 and about half as large as the axial extent A of the receiving groove 17. The ratio between a minimum material thickness a of the connecting piece 3, the axially in the region of the receiving portion 19th is present, and an inner diameter b of the connecting piece 3 is about 1:10. For variants of the fitting assembly 1, this ratio is between 1:10 and 2:10. Between the inlet section 13 and the peripheral collar 12 of the connecting piece 3 has a designed as an oblique, conical bearing wall 22 stop collar for the MKV tube 2. The support wall 22 closes with a longitudinal axis of the connecting piece 3, which in the inlet section 13 with the longitudinal axis 10 of the MKV Tube 2 coincides, an angle ß of about 40 °. Other angles of the abutment wall 22 to the longitudinal axis 10 in the range between 30 ° and 60 ° are possible.

The difference between the angles α and β is approximately 25 ° in the illustrated embodiments. Other angle differences between 15 ° and 35 ° are possible.

The materials for the inner layer 5 of the MKV tube 2 and the connecting piece 3 and the two angles α, ß are coordinated so that an inner, end-side bevel edge 23 of the inner layer 5 of the MKV tube 2 rests linearly circumferentially against the abutment wall 22. So there is no surface contact between the inner layer 5 and the abutment wall 22 before.

Between the abutment wall 22 and the peripheral collar 12 of the connecting piece 3 has an outer peripheral locking groove 24 in which an inner locking collar 25 of a plastic retaining ring 26 is received. Between the front end 8 of the MKV tube 2 and the locking collar 25 remains a gap. The MKV tube 2 is thus not on the plastic retaining ring 26.

The latching groove 24 is limited to the abutment wall 22 by a circumferential bead 27, over which the plastic retaining ring 26 is pushed onto the connecting piece 3 when it is snapped on. Opposite, the locking groove 24 bounded by a circumferential abutment wall 28 of the circumferential collar 12, against which the plastic retaining ring 26 abuts when latched. From a groove bottom 29 of the latching groove 24, a radially outer section of the stop wall 28 projects back axially via a step 30, so that in the rebounding region the latching groove 24 is widened. When latched plastic retaining ring 26 remains between the plastic retaining ring 26 and the recessed portion of the stop wall 28, a gap s. In an alternative embodiment of the connection piece 3, the stepwise return of the stop wall 28 via the step 30 is not complete, but is present in peripheral sections. Between these circumferential sections of the groove bottom 29 of the locking groove 24 is widened generally by the gap width s. In particular, there may be five recessed circumferential sections with a circumferential extent of 40 °, between which intermediate spaces with gap 32 extending through to the groove base 29 are located with a circumferential extent of 32 ° each. By this variant of the configuration of the connecting piece 3 with section-wise return via the step 30 material is saved compared to a full-circumferential return. This is particularly advantageous if the connecting piece is made of plastic, especially if this is done by injection molding.

The plastic retaining ring 26 has a substantially L-shaped cross section, wherein the ratio between the axial extent and the radial extent of the plastic retaining ring 26 may have values between 0.9 and 1.2.

Towards the radially outward direction, the latching collar 25 of the plastic retaining ring 26 initially widens via a step 31. This expansion via the step 31 can be carried out in a first, not-shown variant in a full-circumjacent manner about the retaining ring symmetry axis 10. In the in Fig. 2 illustrated embodiment of the retaining ring 26, the step 31 in five peripheral portions of the retaining ring 26 is executed. The guided in Fig. 2 in the upper half section through the retaining ring 26 is effected by such a peripheral portion. The lower section is guided in a plane between two such peripheral sections, wherein an end wall of the peripheral section can be seen. The peripheral portions extend around the retaining ring symmetry axis 10 over an angular range of 40 °. Accordingly, the spaces between two peripheral portions in the circumferential direction, the ring axis of symmetry 10 has a circumferential extent of 32 °. Such an axially widened section 32 is to complete the L-shaped cross-section of the retaining ring 26 in a bent by 90 ° sleeve locking portion 33 of the plastic retaining ring 26 via. Axially, the sleeve locking portion 33 partially overlaps with the inlet portion 13 of the connecting piece 3. The sleeve locking portion 33 defines a locking groove 34 for latching receiving a diameter-expanded, remote inlet crimping portion 35 of a compression sleeve 36 of Anschlußfϊttings 4. The plastic retaining ring 26 is located in Area of the sleeve locking portion 33 radially over the compression sleeve 36 via. The remote from the crimping portion 35 is substantially free of play received in the locking groove 34, so that, apart from a production-related and inevitable tolerance, tilting of the compression sleeve 36 relative to the plastic retaining ring 26 and thus to the connecting piece 3 is practically impossible.

The compression sleeve 36 axially covers the entire inlet section 13 of the connecting piece 3 and has, apart from the collar side, so inlet remote flare section 35 and from an opposite, so inlet side flare section 37 an inner diameter which is slightly larger than the outer diameter of the MKV tube. 2 The Federal Government delabschnitt 35 runs in a shallow bead, while the inlet-side flare section 37 terminates in an edge. In order to facilitate latching of the compression sleeve 36 into the latching groove 34, the sleeve latching portion 33 has a leading inlet chamfer 38.

Adjacent to the collar-side flaring section 35, the compression sleeve 36 has three viewing holes 39. Axially slightly offset to the inlet side opposite the viewing holes 39, but still collar side, the compression sleeve 36 has three grits 40. In the circumferential direction around the compression sleeve 36, the grains 40 are each located between two adjacent sight holes 39. At the location of the grains 40, the inside diameter of the compression sleeve 36 is reduced by about 0.2 mm. For grain sizes, the reduction in internal diameter is between 0.1 and 0.25 mm.

1 and 2 show the connection fitting 4 in the still-pressed state of the compression sleeve 36, wherein a pressing jaw 41 of an otherwise not shown, several such pressing jaws having pressing tongs in outer contact with the compression sleeve 36 is shown. Instead of the term "pressing jaw", the terms "pressing leg", "pressing member" and "pressing segment" are also familiar. Instead of the term "pressing tongs" is also the term "pressing tool" familiar. The crimping tool is used for compressive fixation of the compression sleeve 36 on the pushed onto the connecting piece 3 MKV tube 2 and thus for compressive fixation of the MKV tube 2 on the connecting piece. 3

The pressing jaws 41 have the compression sleeve 36 faces a central web 42 which comes at the height of the receiving groove 17 on the compression sleeve 36 to the plant. The central web 42 has an axial extension that the receiving groove 17 covered with the receiving ribs 21. Spaced apart from the central web 42, each pressing jaw 41 has two further side webs 43, 44.

In a first embodiment variant of the pressing jaws 41, the center bar has a total width, that is to say an axial extent, of 5.7 mm. The Seitenbzw. Outer webs 43, 44 have an axial extension of 1.0 mm. The mutually facing walls of the side webs 43, 44 have a distance from each other of 15 mm. This results in a total width between the outer walls of the side webs 43, 44 of 17 mm. The ratio of the axial extent of the central web to the total width is thus 5.7 to 17, that is about 1: 3. The ratio of the side bridge width to the total width is 1:17.

In an alternative dimensioning variant of the pressing jaws 41, these also have a total width of 17 mm, an axial extension of the center web of 5.9 mm, a distance between the side walls of the side webs of 14.4 mm facing each other and a side web width or axial extent of 1.3 mm. The ratio of the middle bridge width to the total width is 5.9: 17. The ratio of the side bridge width to the total width is 1.3: 17.

The collar-side, so inlet remote side bar 43 is in the illustrated pressing position of the pressing jaw 41 laterally on an end wall 45 of the sleeve locking portion 33 of the plastic retaining ring 26 at. The inlet-side side web 44 rests against the compression sleeve 36 in a section adjoining which immediately on the inlet side the flare section 37 enlarging in diameter adjoins. In the pressing position of the pressing jaw 41, the crimping pliers are thus guided between the plastic retaining ring 26 and the inlet-side crimping section 37 of the compression sleeve 36. For receiving the plastic retaining ring 26 in the pressing position, the pressing jaws 41 have a circumferential recess 46. The latter has a depth T which is only slightly larger than the radial projection R of the plastic retaining ring 26 via the compression sleeve 36.

In the pressing position of the pressing tongs with plastically deformed compression sleeve 36 and plastically deformed MKV tube 2, as shown in FIG. 2a, therefore lies in compressed compression sleeve 36, so if the pressing jaws 41 were still moved a bit to the longitudinal axis 10, a base 47 of the circumferential recess 46 on an outer circumferential surface 48 of the plastic retaining ring 26 at.

With the fitting mounting assembly 1, a sealing compound between see the MKV pipe 2 and the connecting piece 3 can be prepared as follows:

First, the connection fitting 4 is pre-assembled. The O-ring 20 is inserted into the receiving portion 19 of the connecting piece 3. The plastic retaining ring 26 is snapped onto the connecting piece 3. Since the latching groove 24 has the widened in Aufreastrichtung outer portion with gap s, the plastic retaining ring 26 can be pressed slightly axially when snapped, as would be possible without the widened portion 32. This ensures a secure locking of the locking collar 25 in the locking groove 24 at the same time running narrow on the bottom side

Locking groove 24. In the locked state of the plastic retaining ring 26 is therefore a secure hold of this to the connecting piece 3 and a minimum axial play of the locking collar 25 in the locking groove 24 guaranteed. After snapping the plastic retaining ring 26, the compression sleeve 36 with the Bördelabschnitt 35 engaged in the locking groove 34 of the plastic retaining ring 26. The connection fitting 4 is then in a preassembled state, in which the compression sleeve 36 is held captive on the connection piece 3.

The MKV tube 2 is initially present without frontal chamfer. The chamfer wall 9 is mounted by inserting the MKV pipe 2 into the connection fitting 4 by a chamfering tool by the user. At the same time, the chamfering tool serves to eliminate an optional ovalization of the MKV tube 2 in the section to be pressed. Such ovalization may result, for example, when the MKV tube 2 is cut to length. After chamfering, the MKV tube 2 is round in the section to be pressed.

At the construction site, the MKV pipe 2 is inserted by the user with the leading inner chamfer 9 in the hollow cylindrical space between the connecting piece 3 and the compression sleeve 36 until the edge of the chamfer 23 comes to rest on the abutment wall 22. The chamfer wall 9 facilitates the pushing on of the MKV tube 2 on the inlet end 1 1 of the connecting piece 3 and the sliding over the MKV tube 2 via the O-ring 20. When pushing over the MKV tube 2 via the O-ring 20 prevents the lateral Appendix the O-ring 20 on the two-sided receiving rib 21 that the O-ring 20 is undesirable taken from the MKV pipe 2. In the retracted position of the MKV tube 2 prevents the stepped execution of the receiving portion 19 in the groove bottom 18 that the O-ring 20 is undesirable axially displaced towards the inlet side and thereby entrains the MKV tube 2 undesirable. Due to the choice of the angle α and ß a defined axial abutment of the MKV pipe 2 is ensured at the connection piece 3. The end 8 of the MKV tube 2 is in particular not pushed onto the abutment wall 22 and not widened by the system on the abutment wall 22. The rib edges 16 on the circumferential ribs 14 and on one of the two receiving ribs 21 secure the MKV tube 2 in this position against undesired displacement relative to the connecting piece 3.

Now the pressing tongs with the pressing jaws 41 according to the illustration according to FIG. 2 are positioned on the pressing sleeve, the pressing jaws 41 being axially guided between the plastic retaining ring 26 and the inlet-side flange section 37. The pressing jaws 41 are then automatically positioned so that the central web 42 is located axially exactly at the level of the receiving groove 17 with the receiving ribs 21.

Now a radial compression of the compression sleeve 36 and the MKV tube 2 by displacing the pressing jaws 41 in the direction of the longitudinal axis 10 of the connection fitting 4 to. The pressing tongs work in the manner of a crimping tool. The compression sleeve 36 and the metal layer 6 of the MKV tube 2 are plastically deformed in the region of the webs 42 to 44, so that on the one hand in the region of the central web 42 a secure sealing of the connection piece 3 on the MKV pipe 2 via the O-ring seal 20th is guaranteed and on the other hand on the plastic deformation in the region of the side webs 43, 44, the MKV tube 2 is securely protected against unwanted slipping from the connecting piece 3. The rib edges 16 engage in the material of the inner layer 5 and act as a barb against such slipping out. The O-ring seal 20 has room in the wide receiving groove 17 to avoid the pressure applied from the outside to compensate. Fig. 2a shows this compressed position. Since during the pressing of the bottom 47 of the circumferential recess 46 comes into contact with the lateral surface 48 of the plastic retaining ring 26 over the entire circumference of the plastic retaining ring 26, the plastic retaining ring 26, for example, as a result of from the inside by as As a result of the pressing operation, radially expanding compression sleeve does not break radially. An undefined deformation of the plastic retaining ring 26 is therefore reliably prevented by this configuration of the circumferential recess 46.

The above description of the assembly and use of the fitting assembly 1 is to be understood only as an example. Other sequences of the involved process steps are possible.

8 and 9 show a further embodiment of a fitting assembly 1. This differs from that of FIGS. 1 to 7 only in that in the embodiment of FIGS. 8 and 9, the receiving groove 17 without a receiving portion 19 with is executed opposite the other groove bottom reduced diameter. The receiving groove 17 in the embodiment according to FIGS. 8 and 9 thus has a groove base with a uniform diameter.

In FIGS. 10 and 11, one of the two pressing jaws 41 is shown in different scales. The two lateral pressing webs 43, 44 have at an inner peripheral portion which is adjacent to a closing plane 49 of the pressing webs 42 to 44, each extending to this closing plane 49 toward circumferential recess 50. Each of the two lateral webs 43, 44 thus has two each other opposite peripheral recesses 50. At the location of the peripheral recesses, the internal diameter of the pressing jaw 41, which is predetermined by the lateral webs 43, 44, increases in size. continuously up to the closing plane 49, wherein the increase in the inner diameter adjacent to the closing plane 49 a maximum of a few tenths of a millimeter, for example, 0.3 mm. On the side applied to the closing plane 49, the peripheral recesses 50 continuously merge into another inner circumferential wall 51 of the lateral pressing webs 43, 44. This results in an edge-free and step-free course of the inner jacket wall 51 even in the region of the transitions to the circumferential recesses 50.

When the compression sleeve is pressed together with the two pressing jaws 41, this design of the peripheral recesses prevents undesired material of the compression sleeve 36 from being squeezed between the two pressing jaws 41 in the region of the closing plane 49 and disturbing the visual impression of the compressed tube connection.

Claims

Schutzansprtiche

1. connection fitting (4) with at least one connecting piece (3) on which a metal-plastic composite pipe (2) can be pushed, with a compression sleeve (36), with a radially over the compression sleeve (36) partially protruding plastic retaining ring ( 26), on the one hand latching with the connection fitting (4), on the other hand latching with the compression sleeve (36) is connected, wherein a circumferential locking groove (24) of the connecting piece (3), in which the plastic retaining ring (26) is accommodated limited is on the one hand by a peripheral bead (27) over which the plastic retaining ring (26) when snapped onto the connecting piece (3) is pushed, and on the other hand by a peripheral stop wall (28) on which the plastic retaining ring (26) strikes when latching, characterized in that the abutment wall (28) of a groove bottom (29) of the locking groove (24), the locking groove (24) widening, axially springs back, so that when latched plastic retaining ring (26)

Gap (s) between the latter and the recessed portion (32) of the stop wall (28) remains.

2. Connection fitting according to claim 1, characterized in that the ratio of an axial extension of the plastic retaining ring (26) to a radial extent of the plastic retaining ring (26) is between 0.9 and 1.2.

3. Connection fitting according to claim 1 or 2, characterized in that the plastic retaining ring (26) has an axial extension between 4 and 6 mm, in particular between 4.3 and 5.5 mm.