GB2306598A - Tube connector - Google Patents

Abstract

The connector for a cylindrical tube (1), or tube portion of a connection piece, has a connecting member (2), a cutting ring (20), and a union nut (11). The cutting ring (20) is located on the tube (1) and, in the fitted condition, cuts by means of its cutting edge (22) into the outer face (4) of the tube (1). The holding ring (15) comprises a conical bore (18) holding the cutting ring (20). By means of a supporting face (16), the holding ring (15) is supported against the end face (6) of the connecting member (2). At its end facing the conical bore (13) of the union nut (11), the holding ring (15) comprises a conical supporting face (19) matching the nut conical bore (13). At its end facing the union nut (11), the cutting ring (20) comprises a conical pressure face (25) also matching the nut conical bore (13). After completion of the tightening operation, the cutting ring fully enters the conical bore (20) of the holding ring (15), and the conical bore (13) of the union nut (11) is supported against both the pressure face (25) and the conical supporting face (19). This ensures that after the connection has been tightened, no further forces can be applied to the cutting ring (20). The holding ring supporting face (16) has outer annular fluting or knurling to prevent rotation.

Description

2306598 PATENTS ACT 1977 GMD/A9003GB/D19 Title: TUBE CONNECTOR

Description of Invention

This invention relates to a tube connector, for connecting to a cylindrical tube or tube portion, comprising a connecting member which has a first conical bore tapering from a radially extending end face of the connecting member and having a preferably 24' cone angle, an adjoining first cylindrical bore and a second cylindrical bore adjoining said first cylindrical bore and having a reduced diameter compared thereto; a union nut through which in use the tube or tube portion extends and which comprises a conical bore which is tapered in a direction opposite to that of the conical bore of the connecting member and which has a preferably 90' cone angle, and having a screw thread engagable with a screw thread of the connecting member; a holdint, ring with a supporting face which is supported against the radially extending end face of the connecting c C1 member and which comprises a conical bore which starts from a second face at the end of the holdine rincy facina the conical bore of the union nut; and a cuttin C) 0 c 9 rine which en-aues the conical bore of the holding ring and which, when the nut has been tichtened, establishes contact with the holding ring by way of a corresponding outer conical face, and which comprises at least one cutting edge and a bore for receivino the tube or tube portion as well as a pressure face which is loaded by the conical bore of the union nut. Such a tube connector will be referred to herein as a tube connector of the kind specified.

Such a connection is described in DE-4038539-Cl wherein the holdine ring, primarily, has the function of a sealing element. The function of holding the Ribe is taken over by the CLIttinu ring which engages a spherical bore of the sealinu element. The sealinu element comprises a step which extends along part of the length of the spherical bore of the connecting member. In this way, the sealing function is separated from the holding function. To improve the sealing function of the sealing element, the latter is either provided with a metallic c BAD ORIGINAL sealing lip in a projection extending into the cone of the connecting member, or an elastomer ring is additionally arranged in front of the sealing element in the fitted condition. The cutting ring is provided with a radial projection which, by means of a suitable contact face, rests aaainst a radially extending annular stop face of the sealing element in the tightened condition, said stop face being associated with the conical face of the nut, the purpose of the above radial projection being to limit the tightening process. However, the cutting ring extends back-wards beyond the end of the sealing element towards the conical bore of the nut, and if a severe tightening operation continues, the orientation of the conical bore of the nut and the cooperating conical face of the cutting ring result in radial deformation which may lead to the tube being contracted. This means that the protection against over- tightening is effected to a limited extent only, and it has to be taken into aCCOUnt that, independently of the size of the tube connection, the shoulder of the cutting ring may comprise a relatively small face.

US-2687315 describes a tube connection which also proposes an annular sealine element which comprises a step projecting into the conical bore of the connectina member. The cutting ring is provided towards the nut and b C c y means of its front re-ion facine the connectin. member it extends into a conical bore of the sealin(y element. No means for limitim, the tightening operation are provided in such a case because even when being tightened, the cutting ring projects axially beyond the annular sealin element towards the conical bore of 9 the union nut.

GB-2080900-A proposes a tube connection comprising a holding c element provided xvith a conical outer face by means of which it at least partially enVaues the conical bore of the connectino member. The holdin(Y element itself c -- -- -- is provided with a conical bore which opens towards the conical bore of the nut and which is en-aved by a CLItting ring. At its end projecting in the fitted condition from the holding element, the cuttino rino is provided with a Cut SO that, c when its conical Outer face is loaded by the conical bore of the nut, there occurs radial deformation which, also towards the nut, IS to CaLISC the clittine, rinu to be c c BAD ORIGINAL 3 jammed towards the tube surface. An elastomer ring is arranged in front of the holding element and the cutting ring and engages the conical bore of the connecting member in front of the holding element and the cutting ring, thus sealing the gap towards the outer face of the tube.

FR-2346617 describes a tube connection wherein the connectina member comprises a stepped cylindrical bore accommodating the tube. In the widened step, there is accommodated a holding ring comprising a radially extending shoulder comprising a stop face by means of which it rests against the end face of the connectina member. In front of the holdina element there is provided a soft seal in the form of a sealing ring which seals the gap between the connecting member, the outer tube face and the holdina element. Towards the end of the nut, i.e. its conical bore, the holding element comprises a conical bore which is engaged by the front end of a cutting ring, the rear end projects from the c 1 W c holdine element in the tiebtened condition. At the nut end, the cutting ring comprises a conical face which corresponds to the conical bore of the union nut.

GB-PS-1317892 proposes a tube connection wherein there is provided a sealina element and a holdino element separated therefrom. The sealing C CY element consists of an outwardly conical ring which engages the conical bore of the connecting member and which is provided with a soft seal received in a groove end of a radially extending stop face supporting a holding ring which, towards the nut, comprises a conical bore which is partially engaged by a cutting rin.. The cutting ring is provided with a conical outer face which corresponds to that of the nut. Furthermore, the holding ring comprises an inwardly pointing collar and, towards the sealing ring, it comprises a radially extending end face by, means of which it rests avainst the radialiv extendin- end face of the sealine c -C1 element, into which the sealing ring, is inserted. The inwardly pointing collar serves for axially supporting the adioinin,o tube. Said support is required when tluhteriin(-, the connection to enSUre that the cuttinu rine cuts into the tube surface c -- W c when bein,, pressed into the conical bore of the holdinu element. In an c BAD ORIGINAL 4 embodiment wherein the holdinc, element itself is provided in the form of a nut, the axial distance of the sealing element is limited.

It is the object of the invention to provide a tube connector which securely clamps in the tube or tube portion while providing an effective protection against over-tightenincy and whose cutting ring, even when extremely high forces are applied, is not sub ected to an impermissibly high degree of radial j c deformation which would result in undesirable radial deformation of the tube or tube portion to he connected to the connecting member.

In accordance with the invention, the objective is achieved in that the face of the holding ring facing the conical bore of the union nut at least partially comprises a conical supporting face whose cone angle matches the conical bore of the union nut and that, in the fitted and ti- htened condition, the cuttine rine extends into the conical bore of the holding ring far enough to allow both the conical supporting face of the holding ring and the pressure face of the cutting rine to rest acainst the conical bore of the union nut.

In a tube connector in accordance with the invention, the holding ring has no sealine function whatsoever. It only ensures that the cuttine rine or clamping ring is given the necessary support to ensure it is held effectively when C w 1 subjected to a high tightening torque. The holding ring effectively prevents any impermissible deformation of the cutting ring under severe tightening conditions.

c C As a result of the radially extendinu face of the holding ring facing the end face c c C1 of the connectine, member, the holdino riny is able to provide axial support without takina over a sealinu function. When fluhtenino the nut, or during c c 1Z c preassembly, the cutting ring is moved by a suitable element relative to the holding rin(y until the conical Outer face of the cutting is aligned with the corresponding conical outer face of the holding ring, i.e. until the union nut (or the respective member provided for preassembly purposes) by, means of its conical bore, is supported on the conical faces of both the holding rine and cutting ring pointing towards the conical bore, so that there is no chance of any further axial relative movement of the cuttin, rino relative to the holdinu rin, or ariv further c c C c 1 BAD ORIGINAL contraction of the cuttinu rine in the radial direction towards the tube. The union nut cannot he tightened any further during the assembly of the connection.

C> cl Equally, the cutting ring end on the side of the nut cannot be deformed by the force of the union nut when the conical bore of the nut has established contact with the conical supporting face of the holding ring. Overall, there is provided a sturdy holding ring and strong support in the axial direction in that the conical supporting face of the holding ring is arranged on a relatively large diameter which, with reference to the nut, is positioned in a region which, even under severe tightening conditions, is able to build tip corresponding counter forces, so that the nut comprises greater reserves against over-tightening To ensure that, when tightening the connection, the friction contact between the union nut and cutting ring does not cause the cutting ring, together with the holding ring and the tube, to carry out a rotational movement, it is proposed according to a further embodiment of the invention that anti-rotation means are arranued to be operable between the connecting member and the holdino rin.. Such a relative movement would be disadvantageous in that a corotatine ttibe leads to torsion in the system, which torsion invariably leads to leaka-es durin- in-service loads.

In a preferred embodiment, the anti-rotation means are provided in the form of friction means which increase the friction between the end face of the connecting member and the adjoining sijpportin(y face of the holding ring C C1 0 contactine sa m c. An advantavemis solinion is achieved in that, in an outer annular reuion, the siipporting face of the holding rinu and/or the end face of the connectin(-, member are/is provided with a knUrled or f1Lited region. However, the knUrICC1 or flUted revIon or the friction increasing means are preferably provided on the siipporting face of the holding ring. It is not a standardised C c C component. SLICII an embodiment enables the supporting face to carry out two fUnctions In an optirritim way, that is it prevents leakae.,,- dUe to the planar and c smooth contact on the end face of the coniiectiii,-, member in the inner narrow annUlar region and it provides non-rotational stipport in the miter knurled or BAD ORIGINAL 6 fluted annular region, which support leads to an increase in friction due to penetration of the surface of the end face of the connecting member. The holding ring may be made of a material which has been heat-treated and thus comprises a greater hardness than the connecting member.

Preferred embodiments of the holding ring and cutting ring are characterised in that the greatest diameter of the conical bore of the holding ring facing the conical bore of the union nut corresponds to the greatest diameter of the conical pressure face of the cutting ring, that the length of the cutting ring in the fitted condition, measured from its greatest diameter to the end comprising the cutting edge, at most corresponds to the length of the conical bore of the holdina ring.

According to a further embodiment of the invention, it is proposed that the holding ring, towards the connecting member, may end in its radially extending supporting face and that the tube or tube portion should extend into the first cylindrical bore of the connecting member.

Such a design is provided for a standard tube connection or for an embodiment comprising a tube portion which itself forms part of the attaching member.

In a further embodiment, this design is put into effect in that the step c formed between the two cylindrical connecting member bores of different c diameters is adapted to serve as a stop face for an end face of the tube or tube portion.

In such embodiments, the scaling function may be achieved entirely by a flexible elastle scaling rin. inserted into a space defined between the outer face of the tUbe, the conical bore of the connecting member and the supporting face.

However, it is alternatively possible to use the conical bore of the connecting member for a so-called scalinu head connection. For this purpose, it is proposed b\, the invention that the holdin. rino, in the re(fion adoinin. its radiall j y extending supporting 1 g face, may be provided with a formed-on scaling head portion which, in the reuion adioinin,,, the supporting face, comprises an outer conical face BAD c)RIGINAL 7 which matches the conical bore of the connecting member and, so as to adjoin same, a cylindrical portion whose diameter matches the first cylindrical bore of the connecting member, and that the bore of the holding ring, towards the sealing head portion thereof, may comprise further a cylindrical guiding bore for receiving the tube or tube portion, and, so as to adjoin same, a through-bore whose diameter is smaller and which extends through the sealing head portion. The formed-on sealing head itself does not take on any sealing functions whatsoever. In cases where preassembly by means of a machine is not envisaged, but where assembly is effected by tightening the union nut, it is proposed that a step face between the guiding bore and the through-bore serves as a stop face for the tube or tube portion. To achieve the required sealing effect, the step face may be provided with a groove holding a sealing ring and, furthermore, the outer conical face of the sealing head portion may comprise a circumferential groove into which a sealing ring has been inserted.

To simplify the assembly of the connection, it is proposed that the holding rinu, touether with the cutting rin., is held by friction locking in a prefitted condition in the threaded bore of the Linion nut.

This solution may be put into effect by an elastic ring being arranged between the outer face of the holding rin(y and the thread of the union nut. The rin(T is preferably held in a groove of the holding ring. The pretension is such that when the connection is tightened, the iinion nia can freely carry out a rotational movement relative to the holdino ring withow movine the holdint, ring 0 c C -- znl The conical bore of the holdling rin. preferably corresponds in form to the conical bore of the connectine member. The bore for the connecting member with a 24' cone is specified by DIN 3861, May 1994 edition, bore form W and ISO 8434-1 for cutting rinus. The conical bore of the union nut is also standardised bv DIN ')870, Mav 1985 edition, form A with a 90' ancTle. This DIN standard corresponds to ISO 8434-1.

Preferred embodiment,, of the invention are diagrammatically c 1 illiistrated in the drawings, wherein:- C BAD ORIGINAL 8 Fiaure 1 shows a first embodiment of a tube connection with a connecting member and part of a tube, before the connection is tightened; Figure 2 shows the connection according to Figure 1 after the union nut has been tightened; Figure 3 shows an embodiment including an attaching member which itself is designed for attaching a tube; the attaching member comprises a tube portion which has to be tightly connected to a connecting member, with the connection being in the tightened condition; Figure 4 shows a tube connection with a connecting member to which it is possible, by means of a sealing heat], to attach an attaching member comprising a tube portion; Fiutire 5 is a longitudinal section throiiuh a further embodiment of a tube connection with an additional elastic ring for pre-fitting the holding ring together vith the cutting ring; and Figure 6 is a view, in the direction X of the arrow, of the supporting face of the holding ring shown in the embodiment according to Figures 1 to 3 C1 4:1 and 5.

Fivures 1 and 2 show a first tUbe connection according to the invention. In the case of this tUbe connection, a tube 1 is to be connected to a connecting member 2. The tube 1 and the connecting member 2 have a common longitudinal axis 3. On its outer Surface, the connecting member 2 is provided with a thread 5 which starts from an end face 6 extending radially with reference to the lonoitudinal axis '). Only part of the connectinty member 2 is shown; towards the left, for example, it comprises an outer face which is provided with ke\ faces to be ent,i,,e(i b\r a tool.

A conical bore 7 comprising a cone angle A of 24' starts from the end face 6 and tapers as it extends away therefrom, beino centred on the lonaitudinal axis It is followed by a first cylindrical bore 8 whose diameter is adapted to receive the tube 1. The first cylindrical bore 8 ends in a stop face 10 from which there extends a second cylindrical bore 9 with a redUced diameter. The stop face E1AD ORIG 9 serves to support an end face la of the tube 1. The connecting member 2 is engagable by a union nut 11 provided with a bore with a thread 12 which matches the thread 5 of the connecting member 2. There now follows, towards the rear end of the union nut 11, a conical bore 13 whose cone anule B is 90' and which ends in a cylindrical bore 14 which comprises a reduced diameter adapted to receive the outer diameter of the tube 1. The union nut 11 has been slid over the tube 1.

Furthermore, there is provided a holding ring 15 whose outer face 17 is of a diameter such that it can be passed over by thread 12 of the union nut 11. The holding ring 15 comprises a supporting face 16 which extends radially with reference to the lonvitudinal axis 3 and which, for supporting purposes, in the c C1 fitted condition, rests against the end face 6 of the connectine member 2. The holding ring has an outer annular knurled or fluted portion 38 on its face 16 (see Figure 6) which has a rotation preventing function during assembly, i.e. when ti(,hteninu the union nut 11. The holdin. rine 15, starting from the supporting C1 c C 0 C1 C face 16, has a conical bore 18 which widens conically towards the conical bore 13 of the union nut 11 and whose cone angle preferably, corresponds to the cone anole A of the conical bore 7 of the connecting member 2. Between the end of c CY the holding ring 15 on the nut side and the outer face 17, there is provided a c -- conical SUpportinu face 19 whose cone angle corresponds to the cone angle B of c C the conical bore 13 of the union nut 11. The holdin- rinu 15 has a length LH c C with reference to its part comprising the conical bore 18.

c There is further provided a cutting rin. 20 whIch, at its end pointing towards the connectinu member 2, I's provided with a cutting edge 22. It is also c -- C possible to provide a plurality of cutting ed-es arranged one behind the other.

On its outer surface, tox,,ards the ciittin(y edge 212, the cutting ring 20 comprises c C c a first outer face portion 23 which may be either cylindrical or a conical face with a cone anole which is smaller than that of the conical bore 18. The greatest C djameter D ' of the cuttino rin. 20 is followeel h,v an outer conical face 24 whose cone anole corresponds to that of the conical bore 18. Furthermore, the cuttint, c C BAD ORIGINAL ring 20 has a bore 21 by which it is slid on to the tube 1. Towards the union nut 11, the cutting ring 20 has a conical pressure face 25 whose cone angle matches the cone angle B of the conical bore 13 of the union nut 11. The greatest diameter of the conical bore 18 of the holding ring 15 has been given the reference symbol D; it corresponds to the diameter D of the cutting ring 20. As can be seen in Figure 2, the greatest length LS of the cutting ring 20 in the fitted condition, i.e. when the cutting edge 22 has penetrated the outer tube face 4, measured between the cuttino edoe 22 and its greatest diameter D ', at most corresponds to the length LH of the conical bore 18 of the holding ring 15.

The union nut 11, starting from its position illustrated in Figure 1, is engaged by means of its thread 12 on to the thread 5 of the connecting member 2 after the cutting ring 20, the holding ring 15 and the soft seal 26 arranged in the C C1 wedge-shaped gap towards the outer tube face 4 and the conical bore 7 in front of the holdina rinu 15 have been slid on to the tube 1 from the end face la. For tie,htenin(3 c, purposes, the conical bore 13 of the union nut 11 is supported against the conical pressure face 25 of the cutting ring '10. As the tube 1, by means of its end face la, is supported against the stop face 10, further tightening results in a relative movement of the cuttinu ring 20 alonu the lonuitudinal axis 3 so that the cuttinw edue 22 is deflected into the outer face 4 of the tube and cuts into same, thus penetrating more deeply the conical bore 18 of the holding ring 15 which rests axially aualnst the end face 6 by means of its supporting face 16 and is thus Linable to carry out a movement relative to the connecting member 2. The cuttin,y ring 20 is moved into the holdinu rin. 15 until the conical bore 18 also comes to rest avalnst the conical supporting face 19 of the holdine ring 15. The connection is then firmly tj-htened. Even if further attempts are made to tighten the union nut 11, any further loadinu of the cutting rinu 20 in the direction of the connectint, member -2 is not possible because the holding ring provides the necessary resistance.

The embodiment accordinu to Fioure.3 constitutes a pre-assembled connection in the tichiened condition. In contrast to the enibodiments accordino c BAD ORA 11 to Figures 1 and 2, there is an attaching member 37 provided with a tube portion 1 '. The attaching member 37 comprises a hexagonal portion which permits the engagement of a tool and is arranged between the tube portion 1 and a further attaching portion provided with a thread. The tube portion 1 ' ends in the end face la. The holding ring 15 with the cutting ring 20 is associated with the tube portion 1 '. Furthermore, the union nut 11 is disposed on the tube portion 1 The connection is firmly tightened, i.e. the holding ring 15, by means of its c Z:1 c supporting face 16 provided with a knurled or fluted portion 38 according to Figure 6, rests against the end face 6 of the connecting member 2, and the cutting ring 20 fully engages the conical bore 18 of the holding ring 15, so that the conical supporting face 19 of the holding ring 15 is in a position in which it aligns with the conical pressure face 25 of the cutting ring 20, i.e. both rest against the conical bore 13 of the union nut 11. The holding ring 15 and cutting ring 20 were aligned relative to one another prior to being assembled with the connecting member 2. This can be achieved by means of a preassembly machine which holds the attaching member 37, so that the union nut 11 carries out a relative movement along the longitudinal axis 3 relative to the tube portion 1 ', with the holdinu rinu 15 being held by a preassembly sleeve. In such a case, assembly with a connecting member 2 can be effected in such a way that a space remains between the end face la of the tUbe portion 1 ' and the stop face 10 of the connectinu member 2. Connections of the type described in connection with FigLire 3 are Used especially in tube connections according to DIN 2353.

FluLire 4 shows a tUbe connection similar to that shown in Figure 3, for a sealinu head connection. There is shown an attaching member 37 provided c with a tube portion 1 '. A union nUt 11 is positioned on the tube portion 1 '; it receives a holdinu ring 15 ' and also comprises a conical SUpporting face 19 for resting auainst a conical bore 13 of the Linion nut. The supporting face 16 of the c c c holdin. ring, comprising a knurled or fluted portion 38, is followed towards the left, towards the bore 9 of the connectinu mernber 2, by a sealing head portion 17. The scaling head portion 27 cornpri 1 1 ISCS all OLItCr conical face 28 which BAD ORIGINAL 12 matches the conical bore 7 of the connectino member 2 and in which there is arranged a circumferential groove 35 for receiving a sealing ring 36 which has a sealina function relative to the conical bore 7 of the connectinw member 2. The outer conical face 28 leads into a projection with a cylindrical portion 29 which extends into the cylindrical bore 8 of the connecting member 2. Said cylindrical bore 8 starts from a step face 32 which serves as a stop face for the end face la of the tube portion 1 ' wherein there is provided an annular groove 33 for accommodatinu a sealine rint, '4 which has a sealing function between the sealing head portion 27 and the tube portion 1 ' of the attaching member 37 '. The holdino rino 15 ' is provided with a ULliding bore 30 extending towards the step face 32 which starts from the conical bore 18 and serves to centre the holding ring 15 ' with the sealing portion 27 relative to the tube portion 1 '. In its conical bore 18, the holdina rinu 15 ' accommodates the cuttino rinu '70 in the same way as described in connection with other embodiments. so that when fully tightened, the union nut 11 is fully supported by means of its conical bore 13 against the conical c pressure face 25 and also a ainst the conical supporting face 19 of the holding 9 rinL, 15 ', so that the connection cannot be tightened an\ further by applying pressure force to the cuttinc, rine 20.

Figure 5 shows a further embodiment of a tube connection wherein, between the union nut 11 and the connectinu member '2, there is avain provided a holdint, ring 15 " ",hose supporting face 16 arranved opposite the end face 6 of the connectino member 2- lis provided with a knurlecl or fluted portion 38 to prevent any, rotation when tlx-,litenirit, the union nut 11. The tube connection is shown in the ti-htened condition. The cutting rin. 20 full en-a-es the holdinu rine 15 AdditionalIv, the outer face 17 of the holdino ring is provided with a uroove 40 holding an elastic rino '9 which en-a-es the thread 12 and holds the union nut 11 with the holdinc, rinu 1 and the cutting, ring 20 touether as a prefitted unit prior to assernbly.

Fli,,ijre 0 shows a of the supporting face 10 of the holding ring 15 or 1 according to Floures 1 to ') ancl, \1th the supportinu face 16 being c C1 c c E1AD OR] 13 provided with a knurled or fluted portion 38 intended to engage the surface of the end face of the connectino member.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realisina the invention in diverse forms thereof.

BAD ORIGINAL 14

Claims (1)

1. A tube connector of the kind specified wherein the face of the holding ring facing the conical bore of the union nut at least partially comprises a conical supporting face whose cone angle matches that of the conical bore of the union nut, and in the fitted and tightened condition, the cutting ring extends into the conical bore of the holding ring far enough to allow both the conical supporting face of the holding ring and the pressure face of the cutting ring to rest against the conical bore of the union nut.

A tube connector according to Claim 1 comprising anti-rotation means c operable between the connecting member and the holding ring.

I- c 3.

A tube connector accordin. to Claim 2 wherein the anti-rotation c means comprise friction means acting between the end face of the connecting c member and the supporting face of the holding ring contacting same.

c C, CY 4.

A tUbe connector accordin. to Claim 3 wherein, in an outer annular region, the SUpporting face of the holding ring and/or the end face of the c -1 connectinu member are/is provided with a knUrled or fluted region.

c A tube connector according to any one of the preceding claims wherein the createst diameter of the conical bore of the holding ring facing the conical bore of the Union nut corresponds to the greatest diameter of the conical preSSLire face of the cutting ring, and the length of the cutting ring in the fitted condition, MCaSUred from its greatest diameter to its end comprising the cutting eds-le, at most corresponds to the lenoth of the conical bore of the holding ring.

0 6. A tube connector according to any one of the preceding claims wherein the holding ring, towards the connecting member, ends at its radially W c c ou ORIGINWL extending supporting face and the tube or tube portion is able to extend into the 0 first cylindrical bore of the connecting member.

7. A tube connector according to Claim 2 or any claim appendant thereto wherein the step formed between the two cylindrical bores of different diameters in the connecting member is adapted to serve as a stop face for an end face of 0 the tube or tube portion.

8. A tube connector according to any one of the preceding claims wherein, in use, a flexible elastic sealing ring is disposed in a space defined 0 c between the outer face of the tube or tube portion, the conical bore of the connecting member, and the supporting face of the holding ring.

1 c c 9. A tube connector according to any one of Claims 1 0 holdino rina, ad'acent its radially extending supporting face, is provided with a c c J 0 0 sealing head portion which, in a region adjacent said supporting face, comprises an outer conical face matching the conical bore of the connecting member and an adjoining cylindrical portion whose diameter matches the first cylindrical bore of the connecting member, the conical bore of the holding ring, towards the c C1 sealing head portion thereof, comprising a cylindrical guiding bore for receiving 1 c o 4 wherein the the tube or tube portion, and an adjacent through bore of reduced diameter which extends through the sealinu head portion.

10. A tube connector accordino to Claim 9,.k,hercin a step face between c said iijidin(, bore and through bore is adapted to serve as a stop face for the tube C_ c or tube portion.

A tube connector accordinty to Claim 10 wherein said step face is provided with a groove holding a sealing rino c -- C C BAD ORIGINAL 0 16 12. A tube connector according to any one of Claims 9 to 11 wherein the 0 1 outer conical face of the scaling head portion has a circumferential groove holding a sealing ring.

0. A tube connector according to any, one of the preceding claims 0 wherein the holding ring and cutting ring are held frictionally in a prefitted t c condition in the threaded bore of the union nut.

14. A tube connector according to Claim 13 wherein an elastic ring is C7 arranged between the outer face of the holding ring and the thread of the union nut.

15. A tube connector according to Claim 14 wherein said elastic ring is held in a groove of the holding ring.

0 16. A tube connector substantially as hereinbefore described with reference to any of the accompanying drawings.

1. C) - 17. A tube connector accordinu to any, one of the preceding claims having a tube or tube portion engaged therewith.

I- is. Any novel feature or novel conilijn.ition of features described herein and/or in the accompanying drawings.

c c BAD ORIGINAL