WO2003012329A1

WO2003012329A1 - Insert for hydraulic connector and hydraulic connector comprising such insert

Info

Publication number: WO2003012329A1
Application number: PCT/IT2001/000410
Authority: WO
Inventors: Walter Tagliaro; Franco Carbonini
Original assignee: Itr S.P.A.
Priority date: 2001-07-25
Filing date: 2001-07-25
Publication date: 2003-02-13

Abstract

An insert for an hydraulic connector for the connection of pipes (90) comprising an inner rubber layer (81), a metal reinforcing core (82), and a rubber covering (83), comprises an internally hollow body (1) having a first portion (2) to be fitted in the free end of the pipe (80), and a ring (50) which is separate from the body (1) but can be associated releasably therewith. The ring comprises an outer annular groove (55) suitable for co-operating with a locking sleeve (90) of the connector in order to restrain the metal reinforcing core (82) of the pipe and to achieve an 'interlock' connection. The first portion (2) of the body (1) has an annular channel (10) suitable for housing the ring completely in order to restrain it in a defined axial position relative to the insert body (1), ensuring quick and precise mounting of the ring on the insert body.

Description

DESCRIPTION

"Insert for hydraulic connector and hydraulic connector comprising such insert"

The present invention relates to the field of hydraulic connectors and, in particular, relates to an insert for a connector of this type.

As is known, a hydraulic connector is a set of parts which is used for the mechanical and hydraulic connection of hydraulic pipes and fixed or movable parts of machines or of systems which are under pressure.

A hydraulic connector is composed, basically, of two parts. A first part of the hydraulic connector, known as the shank or insert, is intended to be inserted, for a predominant portion of its length, in a hydraulic pipe to be connected, at a free end of the pipe. The insert is constituted by an internally hollow body, which is straight or elbowed with various elbow angles (for example, 45° or 90°), with .a first, substantially cylindrical, longitudinal portion of predominant length which constitutes the actual insert, a second longitudinal portion which is shaped so as to constitute a mechanical locating element conforming to international standardization norms (for example, hexagonal) , and a third longitudinal, mechanical and hydraulic connection portion which is also formed in accordance with international standardization norms and, for example, in the case of an insert for a male connector, is of an externally-threaded, cylindrical shape.

A second part of the hydraulic connector, known as the locking ring, bush, or even sleeve, is constituted by a hollow cylindrical body to be fitted on the free end of the hydraulic pipe in which the insert will be fitted and, after the insert has been fitted in the pipe, to be clamped onto the pipe by radial compression.

Typical materials used for the production of the two above-mentioned parts are, for example, free-cutting steels or other steels.

Connectors of the type described are used in combination with hydraulic pipes comprising an innermost layer or lining made of rubber compatible with the fluid to be conveyed and of a thickness suitable for the application, a metal reinforcing core, and an outer layer, also known as the covering, which is made of rubber selected so as to be resistant to the environmental agents in which the pipe is to be used, and which protects the metal reinforcing core. The metal reinforcing core which, amongst other things, performs the function of containing the pressure exerted by the fluid on the rubber lining, may be of two types; in so-called spiral-reinforced pipes, the reinforcing core is constituted by a package of spirals (four or six spirals) arranged in opposition to one another. In so-called braided pipes, the reinforcing core is constituted by a steel-wire braid or by two steel-wire braids with a thin rubber layer interposed.

The pipes and the connectors are produced in a vast range of sizes, particularly of diameters, to satisfy a large number of applications.

Coupling between the connector insert and the pipe is achieved by one of three different techniques.

A first technique is known as the "no-skive" technique. In connectors produced for this type of application, the most extensive portion of the insert has a corrugated surface and the locking sleeve has an internal longitudinal series of fairly pointed annular projections constituting teeth which can penetrate the rubber covering of the pipe.

The "no-skive" technique provides for the locking sleeve to be fitted on the free end of the pipe; the locking sleeve initially has an inside diameter larger than the outside diameter of the pipe and can therefore be fitted without difficulty. The insert is then fitted in the pipe, at its free end. The locking sleeve is then clamped onto the pipe by radial compression.

Coupling is achieved by mechanical connection between the teeth of the locking sleeve and the rubber covering of the pipe, the teeth penetrating the rubber covering, and between the rubber lining of the pipe and the corrugated portion of the insert.

This coupling technique is characterized by low production costs and offers adequate guarantees of hydraulic leaktightness and mechanical strength.

A second coupling technique is known as the "skive" technique. In connectors designed for this coupling technique, the most extensive portion of the insert again has a corrugated surface; the locking sleeve again has an internal longitudinal series of annular projections, but they are not pointed as in locking sleeves for "no-skive" coupling since, as will be explained, they do not have to penetrate the rubber covering but have to press against the metal reinforcing core.

The "skive" technique provides for a preliminary step of the removal (or stripping, hence the term "skive") of a portion of the rubber covering which covers the pipe, at the free end of the pipe, so as to expose the underlying metal reinforcing core. The locking sleeve is then fitted on the free end of the pipe and the insert is fitted in the pipe at its free end. The locking sleeve is then clamped onto the metal reinforcing core of the pipe by radial compression. Coupling is achieved by mechanical connection between the teeth of the locking sleeve and the metal reinforcing core and between the rubber lining of the pipe and the corrugated portion of the insert.

This coupling technique is characterized by production costs which again are sufficiently low, but are greater than those of the "no-skive" technique because of the pipe-stripping step and, moreover, offers better guarantees of mechanical strength.

A third coupling technique is known as the "interlock" technique. A connector intended for this application is formed in a manner such that its portion of predominant length which is to be inserted in the pipe has, in addition to the surface corrugation of the end section, and in the vicinity of the hexagonal intermediate portion, a cradle profile defined by a pair of opposed annular projections between which an annular groove is defined. The locking sleeve in turn is shaped so as to have, in addition to the longitudinal series of annular projections for cooperating with the metal reinforcing core, a further annular projection in a position which, in use, will correspond to that of the groove defined in the insert.

The "interlock" technique provides for a first step of the removal (stripping) of a portion of the rubber covering which covers the pipe in the vicinity of the free end of the pipe and a second step of the removal of a shorter portion of the rubber lining of the pipe. The locking sleeve is then fitted on the free end of the pipe thus prepared and the insert is fitted in the pipe, at its free end. A step of radial compression of the locking sleeve onto the metal reinforcing core of the pipe then follows .

Coupling is achieved by mechanical connection between the teeth of the locking sleeve and the metal reinforcing core of the pipe and between the core and the insert. Moreover, a band of the metal reinforcing core of the pipe is deformed and fitted in a restrained manner between the groove provided in the insert of the connector and the corresponding tooth of the locking sleeve; this prevents the connector from slipping off the pipe when subjected to pressure.

This coupling technique is characterized by higher production costs than the preceding two techniques, but these are accompanied by optimal mechanical strength characteristics . It is necessary to provide for the manufacture of components having particular shapes, according to the coupling technique to be used. In fact, as is clear from the description provided above, the locking sleeve has a different shape according to whether a "no-skive", "skive" or "interlock" coupling is to be achieved. The insert of the connector also has to have a different shape in dependence on whether a "no-skive", "skive", or "interlock" coupling is to be achieved. Moreover, the above-mentioned elements have to be produced in a variety of sizes, diameters and types of hydraulic connection, in dependence on the possible applications as well as on the variety of spatial shapes of the connectors (straight or elbowed with various elbow angles) .

The current tendency in the field is to produce a connector which is formed by an insert, a locking sleeve, and a ring which can be associated with the insert . A "skive" or "no-skive" coupling can be achieved by using purely an insert with the appropriate locking sleeve and an "interlock" coupling can be achieved by fitting the ring on the insert and associating the respective locking sleeve therewith. An application in this sense is described in International application No. PCT/GB94/00681.

With reference to the document cited, a pipe connector which comprises an insert, an adapter ring which can be associated with the insert, and a locking sleeve which can restrain a core of the pipe on the adapter ring is described.

The adapter ring has a substantially cylindrical and smooth outer surface and, under the effect of the compression exerted by the locking sleeve when it is fitted and compressed onto the insert, defines a region which houses the core of the pipe.

The pipe keeps the adapter ring in abutment against a shoulder of the insert by means of the reinforcing liner. The solution described in the document cited makes it difficult to position the adapter ring axially relative to the insert. In fact, this positioning is performed by the reinforcing .liner of the pipe which holds the ring against the shoulder 6 of the insert. During the fitting of the locking sleeve on the insert in order to restrain the core of the pipe, or during the operations to clamp the locking sleeve onto the insert, the end of the pipe often moves from the position in which it holds the ring against the shoulder, causing the ring also to move. Moreover, the arrangement described in the document cited has the disadvantage of requiring a very high radial compression force to be exerted on the locking sleeve to enable the adapter ring to be deformed in order to create the region in which the core of the pipe has to be housed, compressed against the insert by the locking sleeve.

In view of the prior art described, an object of the present invention is to provide an insert for hydraulic connectors which overcomes the disadvantages explained above.

According to the present invention, this object is achieved by means of an insert for a hydraulic connector, particularly for connecting pipes comprising an inner rubber layer, a metal reinforcing core, and a rubber covering, the insert comprising: an internally hollow body with a first portion to be fitted in a pipe, at a free end thereof, and an element which is separate from the hollow body but releasably associable with the first portion thereof. In the above-mentioned insert, the separate element comprises a region of a shape suitable for cooperating with a locking sleeve of the connector, which locking sleeve can be associated with the insert in order to restrain the metal reinforcing core of the pipe. The insert is characterized in that the first portion of the hollow body comprises an annular channel suitable for completely housing the separate element in order to restrain it in a defined axial position relative to the hollow body. The characteristics and the advantages of the present invention will become clearer from the following detailed description of two possible practical embodiments thereof, given purely by way of non-limiting example in the appended drawings, in which: Figure 1 shows, in an exploded, perspective view, not to scale, an insert for a hydraulic connector according to a possible embodiment of the present invention,

Figure 2 is a partially-sectioned, elevational view, not to scale, of a hollow body of the insert shown in Figure 1,

Figure 3 shows the detail III of the insert body of Figure 2, on an enlarged scale,

Figure 4 shows the detail IV of the insert body of Figure 2, on an enlarged scale,

Figure 5 is an elevational view, not to scale, of a ring of the insert which can be associated releasably with the insert body of the preceding drawings,

Figure 6 is a plan view of the ring of Figure 5, not to scale, Figure 7 is a partially-sectioned, elevational view, not to scale, of a first type of locking sleeve of the connector, which can be associated with the insert body of the preceding drawings in order to achieve a "no-skive" coupling with a hydraulic pipe,

Figure 8 shows, in section and not to scale, the insert body of the preceding drawings, coupled with a hydraulic pipe in accordance with the "no-skive" technique by means of the locking sleeve of Figure 7, Figure 9 shows, in ^' a partially-sectioned elevational view, not to scale, a second type of locking sleeve of the connector, which can be associated with the insert of the preceding drawings, including the ring, to achieve an "interlock" coupling with a hydraulic pipe,

Figure 10 shows, in section and not to scale, the insert of the preceding drawings, coupled with a hydraulic pipe in accordance with the "interlock" technique by means of the locking sleeve of Figure 9, Figure 11 shows a variant of the insert body according to the present invention, in a partially- sectioned, elevational view.

With reference to the drawings and, in particular, to Figure 1, this shows an insert for a hydraulic connector for the connection of pipes comprising^' an inner rubber layer, a metal reinforcing core, and a rubber covering, the insert comprising a hollow body 1 and a separate element which can be associated releasably with the hollow body and which is preferably in the form of a ring 50.

With reference to Figures 2 to 4, these show a portion of the insert, which portion is also known as the shank and is intended to be associated, hydraulically and mechanically, with the pipe. In the preferred embodiment of the invention, the shank and the pipe are associated, at a free end of the pipe, by the insertion of a portion of the shank in the pipe.

The shank which, in the embodiment shown, is straight, is constituted by a generally cylindrical body 1, which extends along an axis X and is hollow internally so that a fluid of a hydraulic circuit in which the connector is to be used can flow through it.

The body 1, which is formed as a single element of suitable material, for example, free-cutting steel or other steels, comprises, from a first end 5 towards a second end 6: a first portion 2 of predominant length to be fitted in the pipe, a second portion 3 which acts as a mechanical locating element and is formed in accordance with international standardization norms and, in the embodiment shown, has a hexagonal section transverse the axis X, and a third, end portion 4 which also conforms to international standardization norms, for the connection of the connector to a further part of the hydraulic circuit; in the embodiment shown, the third portion is cylindrical and externally threaded and the connector is thus of the male type.

With reference to Figure 2, in the first portion 2 of the body 1, it is possible to identify, in turn, starting from the end 5, a first, mouth section 7, the outer surface of which is substantially smooth, and which is slightly tapered towards the end 5, a second section 8 the surface of which is preferably corrugated in the manner which will be explained further below, a third section 9, a fourth section 10 with a substantially smooth outer surface and substantially uniform diameter, and a fifth and last section 10'.

The second section 8, a detail of which is shown on an enlarged scale in Figure 3, has a corrugated surface, as stated, and comprises an axial series of regions of variable diameter which define corrugations; in particular, the second section 8 comprises a periodic series of single corrugations 11 (four corrugations in the embodiment shown) .

Each single corrugation 11 comprises, along the axis X in the direction from the end 5 to the end 6, a section 12 of substantially uniform diameter equal to Dl adjoining a subsequent section 13 the diameter of which increases progressively from the initial diameter Dl to a final diameter D2 where D2>D1. The section 13 adjoins a subsequent section 14 the diameter of which decreases, for example from D2 to Dl .

A portion of the third section 9, the fourth section 10, and the fifth section 10' of the portion 2 of the body 1 are shown on an enlarged scale in Figure 4.

In particular, the third section 9 comprises a section 15 of substantially uniform diameter equal to Dl adjoining the section 13 of the last single corrugation 11 of the section 8, followed by an outwardly-flared section 15' . The section 15' is followed by a section 16 with a substantially smooth surface and substantially uniform diameter.

The section 16 adjoins the section 10, forming a catch surface 16'. The section 10 is constituted by an annular channel shaped by a series of two sections 10a and 10b. The section 10a of the annular channel 10 has a substantially uniform diameter and^' preferably has a smooth surface. The following section 10b is flared slightly outwards and terminates against a shoulder 17 of the section 10', forming an abutment surface 17'. The section 10' also comprises an annular seat 18 delimited by a collar 19 of the section 3.

Figures 5 and 6 show, in detail and in an elevational view and a partially-sectioned plan view, respectively, an internally hollow, annular element 50 which can be associated releasably with the insert body 1 of the connector.

In particular, the annular element 50 can be associated with the insert body 1 by being fitted on the portion 2 of the body until it is housed completely in the annular channel 10 and is restrained in a defined axial position relative to the insert body 1.

The annular element 50 is substantially a ring with an inner surface 51 comprising a series of two surfaces 51' and 51'' which form a profile complementary to the profile of the annular channel 10.

The annular element 50, which is made of a material with properties of resilient deformability, for example, harmonic steel, has an axial slot 52 splitting the ring. The resilience properties of the material and the presence of the axial slot 52 enable the ring to be fitted on the first portion 2 of the body 1.

The ring 50 is fitted on the first portion 2 of the body 1 by being slid as far as the annular channel 10 of the body 1. In the region of the annular channel 10, the ring 50 springs back to its original configuration prior to mounting, contracting into the channel 10 so as to be disposed in a defined axial position relative to the insert body. The ring 50 has an outer surface 53 which is shaped by two projections 54, 54' extending on a portion of its outer surface 53. The projections 54 and 54' define an annular groove 55 in the outer surface 54 of the ring.

Figure 7 shows another component of the connector, in particular, a locking sleeve 70 which can cooperate with the insert body 1 of Figures 2 to 4 for coupling with a hydraulic pipe achieved by the so-called "no- skive" technique.

The locking sleeve 70 comprises a substantially cylindrical body 71 of axis Z which is hollow internally so that it can be fitted on the pipe. The body 71 of the locking sleeve 70 has two ends 72 and 73.

From the end 72 towards the end 73, the body 71 of the locking sleeve 70 has a first section 74 to be positioned in the region of the annular seat 18 of the body 1. This is followed by a section 75 with a larger inside diameter than the section 74, to be positioned in the region of the shoulder 17.

Continuing towards the end 73, the locking sleeve has an internal axial series of annular projections 76 (four projections in the embodiment shown) which have triangular profiles in cross-section and are sufficiently pointed to be able to penetrate the rubber of the pipe covering. The locking sleeve 70 preferably comprises, in its interior, a further, chamfered, generally rounded, annular projection 77.

The chamfered annular projection 77 is preferably arranged so as to be the projection which is closest to the end 73 of the locking sleeve, in order not to penetrate the rubber layer of the pipe.

Figure 8 shows, in section, the connector including the insert body of Figures 2 to 4 and the locking sleeve of Figure 7, coupled with a pipe 80 by the "no-skive" coupling technique.

The pipe 80 comprises a rubber lining 81, a metal reinforcing core 82, for example, of the above-described braided or spiral type, and a rubber covering 83.

The "no-skive" coupling method provides for the locking sleeve 70 to be fitted on the pipe and the portion 2 of the insert 1 to be fitted in the pipe, at a free end thereof.

The locking sleeve 70 which, in its original configuration prior to fitting on the pipe, has an internal diameter larger than the outside diameter of the pipe, is then subjected to radial compression so as to clamp the pipe between the locking sleeve and. the underlying insert body.

The projections 76 penetrate the rubber of the covering 83 of the pipe 80 as if biting into it, clamping the rubber lining 81 inside the pipe against the corrugations of the insert body which thus ensure hydraulic leaktightness and oppose removal of the pipe.

The chamfered annular projection 77 preferably does not penetrate and break the covering 83 of the pipe, avoiding stripping of the section of pipe 80 which is outside the locking sleeve when the connector is in use.

In other words, the annular projection 77 forms the so-called "bad weather seal"; the projection presses against the covering 83 of the pipe in the end portion of the covering, restraining it inside the locking sleeve and, at the same time, preventing the metal core 82 from coming into contact with moisture, water and the like. When the locking sleeve is in the mounted configuration on the insert, the section 74 of the end 72 is housed in the annular seat 18 of the insert body and the section 75 bears on the surface of the shoulder 17 of the insert body 1. Figure 9 shows another type of locking sleeve 90 suitable for use in combination with the insert body of Figures 2 to 4, associated with the annular element of Figures 5 and 6, to achieve an "interlock" coupling with a hydraulic pipe. The locking sleeve 90 also comprises a hollow cylindrical body 91 of axis K, with two ends 92, 93. From the end 92 towards the end 93, the body 91 has a first section 94 to be positioned in the region of the annular seat 18 (Figure 10) of the body 1. This is followed by a section 95 which has a larger inside diameter than the section 94, and is to be positioned in the region of the shoulder 17 (Figure 10) of the body 1.

Continuing towards the end 93, inside the locking sleeve 90, in a preferred embodiment, there is an axial series of annular projections 96 (two projections in the embodiment shown) which are similar in shape and preferably have trapezoidal cross-sections.

Moreover, in a preferred .embodiment, the internal surface of the locking sleeve 90 has blunt annular projections 97 (two projections in the embodiment shown) and rounded annular projections 98 (one projection in the embodiment shown) with a function similar to that already described for the blunt annular projections 76 and the rounded annular projection 77 of the locking sleeve 70 for a "no-skive" coupling. When the locking sleeve 90 is in the mounted configuration on the insert with the locking sleeve 90 tightened, the annular projections 96 act substantially on the section of reinforcing core 82 of the pipe which remains free of the lining 81 and of the covering 83 of the pipe.

These projections press the exposed portion 82 of the reinforcing core against the surface of the underlying insert, generally in the region of the annular groove 55 of the ring 50, forcing a portion of the reinforcing core 82 into the groove 55.

The cross-sections of the projections 96, which are preferably trapezoidal, facilitate the action of the projections 96 on the portion of the reinforcing core 82 to be pressed into the groove 55 of the ring 50.

The annular projections 97 are sufficiently pointed to be able to penetrate easily into the section of the rubber covering of the pipe .which is fitted on the insert . Figure 10 shows, in a view similar to that of Figure 8, the connector including the insert body 1 of Figures 2 to 4 with the associated annular element 50 of Figures 5 and 6 and the locking sleeve 90 of Figure 9, coupled with the pipe 80 by the "interlock" technique. For this purpose, a section of the covering 83 and a section of the lining 81 are removed from the pipe 80 so as to leave an end section of the metal reinforcing core 82 free.

The annular element, preferably in the form of a ring 50, is fitted on the insert body 1. The ring 50 is slid along the section 2 of the insert body 1, opening out resiliently by virtue of the axial slot 52.

In the region of the annular channel 10, the ring 50 contracts into the channel 10 and is positioned on the insert body in a stable manner. The axial position of the ring 50 on the insert body 1 is ensured and set by the abutment surface 17' and by the catch surface 16' of the insert body 1.

In its original configuration prior to mounting on the insert body and on the pipe, the locking sleeve 90 has an inside diameter larger than the outside diameter of the pipe. It is fitted on the insert body 1, provided with the ring 50, and is subjected to radial compression so as to clamp the pipe between the locking sleeve and the underlying insert body.

The chamfered annular projections 96 of the locking sleeve 90 compress the free section of the reinforcing core 82, forcing it to deform at least partially within the annular groove 55 of the ring 50 fitted on the insert body 1. The blunt annular projections 97 of the locking sleeve 90 act on the reinforcing core 82, compressing the lining 81 of the pipe against the corrugations 11 of the insert 1. Figure 11 shows an insert for a female hydraulic connector in a view similar to that of Figure 2.

This type of insert differs from that described above solely in the shape of the portions 3 and 4, whereas the portion 2 to be fitted in the pipe to be connected is identical to that described above.

Naturally, the present invention applies not only to straight inserts such as those described but, in general, to inserts of any type for straight or elbowed hydraulic connectors, irrespective of the elbow angle. As is shown by the foregoing description, the present invention has the unusual advantage of enabling the ring to be positioned axially relative to the insert body quickly and precisely and kept in position, facilitating the formation of "interlock" connections. The connector may advantageously be sold in the form of a kit including an insert body, an annular element and locking sleeves. The user can thus purchase a connector which can be used to achieve any one of the various types of coupling with a pipe. Alternatively, a kit including an insert body and an annular element may be sold, leaving the user to decide which type of locking sleeve to purchase, in dependence on the type of hydraulic coupling to be achieved. As a further alternative, a kit including an insert body and a locking sleeve pre-pinched onto the insert may be sold.

Clearly, variations and/or additions may be applied to the embodiments described and illustrated above without thereby departing from the scope of protection of the invention defined in the appended claims.

Claims

1. An insert for a hydraulic connector, particularly for connecting pipes (80) comprising an inner rubber layer (81), a metal reinforcing core (82), and a rubber covering (83) , the insert comprising:

- an internally hollow body (1) having a first portion (2) to be associated with a pipe (80) at a free end of the pipe, and - an element which is separate from the hollow body (1) but releasably associable with the first portion (2) of the hollow body, in which the separate element comprises a region of a shape suitable for cooperating with a locking sleeve (90) of the connector, which locking sleeve can be associated with the insert in order to restrain the metal reinforcing core (82) of the pipe, the insert being characterized in that the first portion (2) of the insert body (1) comprises an annular channel (10) suitable for completely housing the separate element in order to restrain it in a defined axial position relative to the insert body (1) .

2. An insert according to Claim 1 in which the first portion (2) of the body (1) is substantially cylindrical and is intended to be fitted in the pipe (80) at the free end of the pipe, the separate element is a ring (50) provided with an outer annular groove (55) suitable for cooperating with the locking sleeve (90) for clamping the pipe (80) in order to achieve an "interlock" coupling in which the reinforcing core (82) of the pipe is clamped in the groove (55) by at least one annular projection (96) of the locking sleeve (90) .

3. An insert according to Claim 2 in which the ring (50) has a longitudinal interruption line (56) and is made of a resiliently deformable material to allow the ring (50) to be fitted on the first portion (2) of the insert body (1) .

4. An insert according to any one of the preceding claims in which at least one section (8) of the first portion (2) of the insert body (1) has a corrugated outer surface.

5. An insert according to Claim 4 in which the at least one section (8) with a .corrugated outer surface can cooperate with the inner rubber layer (81) of the pipe (80) to form a hydraulic seal.

6. A connector for hydraulic pipes comprising an insert according to any one of the preceding claims and a locking sleeve for clamping the pipe (80) onto the insert body.

7. A connector according to Claim 6 in which the locking sleeve for clamping the pipe (80) onto the insert body (1) has at least one rounded annular projection (77, 98) for pressing the pipe onto the insert body (1) .

8. A connector according to Claim 6 or Claim 7 in which the locking sleeve is of the type which can cooperate with the insert body (1) to achieve a "no- skive" coupling or a "skive" coupling with a pipe.

9. A connector according to Claim 6 or Claim 7 in which the locking sleeve is of the type which is suitable for cooperating with the insert to achieve an "interlock" coupling with a pipe.

10. A kit comprising an insert according to any one of Claims 1 to 5, a first locking sleeve (70) which can be associated with the insert body, without the separate element, in order to achieve a "no-skive" coupling with a pipe (80), and a second locking sleeve (90) which can be associated with the insert, with the separate element, to achieve an "interlock" coupling with the pipe (80) .