Threaded connection

Abstract

The present invention provides a mechanical fitting for crimping connection with a pipe on one side and for threaded connection with another pipe or fitting on the other side, the mechanical fitting comprising a main fitting body (10), having an internal support (15) for crimping connection, the internal support extending between a free end to a fitting head (23) of a larger diameter than the internal support (15), a threaded insert (40) on the other axial side for threaded connection with another pipe or fitting. The threaded insert (40) is received in the fitting head (23). The main fitting body is made of a polymeric fitting body material suitable for crimping and the threaded insert is made of a polymeric insert material suitable for threaded connection, the main fitting body and the threaded insert being bi-injected. A method of manufacturing such a mechanical fitting is also disclosed. Figure for abstract: Fig.1.

Description

Title of the invention: Threaded connection Technical field

[0001] The present invention relates to mechanical fittings, compression fittings, press fittings or push-fit fittings, and more particularly to a mechanical fitting for a threaded connection and a press connection otherwise called crimping, as well as to a method of manufacturing a mechanical fitting for a press connection with a pipe on one side and for a threaded connection with another pipe or fitting on the other side. PREVIOUS ART

[0002] Compression fittings, crimped fittings and socket fittings, which allow pipes to be connected by compression and deformation using one or two sleeves, are well known in the field of installation of tube, pipe and conduit systems, for example for water, gas or heating.

[0003] Tube, pipe or conduit systems are assembled in several steps: first, the pipes are inserted into a fitting; then, in the case of a crimped fitting, the fitting is crimped to ensure good mechanical strength and a watertight installation. Crimping is essentially done by pressure on the fitting, which causes deformation or shaping of the fitting relative to the pipe to which it is connected. Pressure is generally exerted on the fitting using a pressure jaw.

[0004] Installing or maintaining a pipe, piping or conduit system requires the assembly of several pipes and fittings. It is essential that each fitting in the installation is properly crimped to ensure the strength and tightness of the entire system or installation. Otherwise, there may be serious safety issues, especially in the case of gas piping systems.

[0005] For different pipe arrangements, press fittings can be designed as curved, angular or T-shaped pieces, with typically one, two or three fitting pieces provided.

[0006] It is known to use crimp fittings made entirely of plastic or crimp fittings whose fitting body is made of metal (brass, stainless steel, etc.), or thermoplastic (PVC, PPSU, PVDF, PPS), which can also be reinforced with a glass fiber reinforcement.

[0007] There have been some concerns with brass fittings because brass fittings often contain a brass alloy to ensure the required mechanical properties of pressure fittings under operational conditions. This has gone particularly true for portable water systems.

[0008] It is therefore desirable to replace brass fittings with plastic alternatives.

[0009] An important issue with replacing brass with plastic is matching the strength in the thread.

[0010] An object of the present invention is to provide a threaded fitting or pipe for a metallic or polymeric mechanical fitting. Summary of the invention

[0011] These and other objects of the present invention are achieved by a mechanical fitting for crimping connection with a pipe on one side and for threaded connection with another pipe or fitting on the other side, the mechanical fitting comprising a main fitting body having an internal support for crimping connection, the internal support extending between a free end to a fitting head with a diameter greater than the internal support, a threaded insert on the other axial side for threaded connection with another pipe or fitting. The threaded insert is received in the fitting head. The main fitting body is made of a polymeric fitting body material suitable for crimping and the threaded insert is made of a polymeric insert material suitable for threaded connection, the main fitting body and the threaded insert being bi-injected.

[0012] The present disclosure provides a mechanical fitting designed to make a secure connection with a threaded fitting or a metal or polymeric pipe, without an intermediate material such as Teflon or similar products to ensure a seal. In order to be able to make a connection between a metal thread and high-tech polymers such as PPSU, PPA and PVDF, the fitting material must have very high rigidity and very high mechanical strength.

[0013] By providing the main fitting body in a material suitable for crimping, and by providing a threaded insert in an insert material suitable for the threaded connection, it is possible to solve the various problems raised by the crimping connection on the one hand, and the threaded connection on the other hand.

[0014] The crimping technology for connecting a flexible hose via a polymer fitting requires the fitting to be strong enough not to collapse under the crimping force, but also flexible enough to withstand large deformation without premature failure. Therefore, the body material, for crimping, must be soft and withstand large deformation without failure. In contrast, the threaded connection requires a harder and wear-resistant insert material, especially when connecting a polymer thread to a metal thread.

[0015] By combining these two materials in a bi-injection process, it is possible to obtain a mechanical connection which exhibits both a very flexible, ductile behavior, with high rigidity and high mechanical strength. These properties are obtained by at least two materials, a soft material for crimping allowing large deformation without failure, and a hard material for the threaded connection, resistant to wear.

[0016] In one aspect, the threaded insert is integrated into the fitting head. The threaded insert may have an insert body, with a thread on an inner surface or an outer surface of the insert body, and an insert head with a diameter greater than the insert body.

[0017] By integrating the threaded insert, it is possible to obtain a robust connection, with a strong mechanical connection between the connection head and the threaded insert.

[0018] In this aspect, the connector head may have an internal housing for receiving the insert head, the internal shape of the connector head housing corresponding to an external shape of the insert head. In particular, the insert head may have an external shape with a plurality of bosses distributed radially and / or axially along the external surfaces of the insert head.

[0019] Complementary shapes help to achieve a strong bond.

[0020] According to one aspect, the insert housing is provided between an enlarged inner head wall of the connector head extending radially from the inner support and an extension projecting radially inwardly.

[0021] A seal housing may be provided within the connector head, for housing a seal in abutment against the extension, on an axial external wall of the extension, opposite the insert housing.

[0022] In one aspect, the body material and the insert material meet at least one of the following criteria:

[0023] the body material and the insert material have overlapping molding temperature ranges,

[0024] a mold shrinkage percentage of the fitting body material and a mold shrinkage percentage of the insert material differ by less than 15%, preferably by less than 10%.

[0025] In one aspect, the body material is PPSU, and the insert material is fiber-reinforced PPS, particularly with 5 to 40% glass fibers.

[0026] In another aspect, the body material is PPA, and the insert material is fiber-reinforced PPA, particularly with 5 to 40% glass fibers.

[0027] In yet another aspect, the body material is PVDF, and the insert material is fiber-reinforced PVDF, particularly with 5 to 40% glass fibers.

[0028] The present invention also provides a method of manufacturing such a mechanical fitting for a crimping connection with a pipe on one side and for a threaded connection with another pipe or fitting on the other side. The method comprises injecting the insert material MI into a rotational mold to manufacture the insert and, once the insert is injected, injecting the body material MB onto the insert, the method comprising forming a chemical bond between the insert and the fitting body.

[0029] The body material MB may be injected onto the insert less than 5 seconds after completion of the insert, the body material and the insert material having overlapping molding temperature ranges. This ensures that the insert material is still at least partially melted, for the formation of the physicochemical bond between the body material and the insert material. The heat of the insert after injection is sufficient to allow the creation of the physicochemical bond with the mechanical connection injected in a second step.

[0030] It is necessary to add a seal on the insert to ensure sealing in the overmolding process.

[0031] The body material may be PPSU, the insert material being fiber-reinforced PPS, in particular with 5 to 40% glass fibers, or the body material may be PPA, the insert material being fiber-reinforced PPA, in particular with 5 to 40% glass fibers, or the body material may be PVDF, the insert material being fiber-reinforced PVDF, in particular with 5 to 40% glass fibers. DESCRIPTION OF DRAWINGS

[0032] Other features and advantages of the invention will become more clearly apparent upon reading the description of several presently preferred embodiments, provided by way of example only, with reference to the attached drawings, in which:

[0033] [Fig. 1] shows a mechanical connection according to a first aspect of the present disclosure, [Fig. 2] shows the mechanical connection of [Fig. 1], in an exploded view,

[0034] [Fig.3] shows details of the mechanical connection of [Fig.l],

[0035] [Fig.4] shows an alternative embodiment of the mechanical connection of [Fig.l],

[0036] [Figures 5] to 8 show various elements usable in a mechanical connection of [Fig.l] according to the present disclosure,

[0037] [Fig.9] shows a mechanical connection according to another aspect of the present disclosure,

[0038] [Fig. 10] shows a sectional view of the mechanical connection of [Fig. 9], in exploded view,

[0039] [Fig. 11] shows an alternative embodiment of the mechanical connection of [Fig.9],

[0040] [Fig. 12] shows another embodiment of an insert in a fitting mechanics of [Fig.9] according to the present disclosure,

[0041] [Fig. 13] shows the mechanical connections of [Fig.l] and [Fig.9] before and after assembly,

[0042] [Fig. 14] represents the progress of a manufacturing process for a mechanical connection.

[0043] In the figures, identical elements are identified by the same reference numbers. DETAILED DESCRIPTION

[0044] The description below refers to union fittings, but is not limiting, and the following description applies to elbow, T-shaped or reducing fittings which can be manufactured on the basis of the same teachings.

[0045] Figures 1 to 8 show a female mechanical connector 1 for connecting a pipe 2 (not shown in [Fig.l]) according to one aspect of the present invention, and Figures 9 to 12 show a male mechanical connector 201 for connecting a pipe 3 (not shown in [Fig.l]) according to one aspect of the present invention. The connections of the pipes and connectors are visible in [Fig. 13], before and after assembly of the female mechanical connector 1 with the male mechanical connector 201.

[0046] The pipe may be, for example, a pipe for / in a piping system for fluid installations inside buildings.

[0047] The pipe may be, for example, a pipe for / in a piping system for fluid installations inside buildings.

[0048] The pipe or tube may be mono-material and made of thermoplastic materials, including but not limited to PE, PB, PEX, PERT, PER or composite with a multi-material pipe structure having different layers of functional materials, such as PEX, PERT, PVDF, aluminum.

[0049] The pipe can also be made of CPVC, PVC and PVC-U for hot and cold water installations.

[0050] The connector 1 is a female connector, which may form one side of a connector having a similar or other type of connector at its other end or side. The connector 1 may also be provided on a port of a fluidic device for connecting a hose thereto.

[0051] The mechanical connection 1 comprises a main connection body 10 intended to receive a pipe.

[0052] The main fitting body 10 is adapted to receive the pipe in the pipe insertion space on one axial side, and a threaded insert 40 on the other axial side for threaded connection with another pipe or fitting.

[0053] The main connector body 10 comprises an internal support 15 and a connector head 23. The internal support 15 extends between a free end of the support 13 up to the connecting head 23 with a diameter greater than the internal support 15.

[0054] A sleeve 5, visible in [Fig.l], surrounds the internal support 15, to fix one end of the pipe on the internal support. The sleeve is a metal sleeve provided for crimping the pipe.

[0055] The internal support 15 and the sleeve 5 define a pipe insertion space extending in an axial direction XX, between a first open end 11 of the mechanical connection, i.e. the end where the pipe is inserted, and the connection head 23.

[0056] The inner support 15 includes a radial recess 16 which extends along the outer surface of the inner support. The pipe may be crimped onto the inner support by compressing the sleeve, in order to compress the pipe and secure the pipe to the inner support.

[0057] The internal support 15 is made of a harder polymer than the pipe, which allows for receiving an internal portion of compressed pipe ejected during the crimping process, in order to ensure sealing without an O-ring insert and to create a sufficient adhesion surface to hold the pipe therein against axial sliding movement due to a pull-out force.

[0058] A circular channel 25 is provided between a radial fold 22 projecting radially outwardly from the internal support and the connecting head 23, as can be seen in Figures 2 and 3. The radial fold 22 allows the metal sleeve 5 to be held, with or without an intermediate insert.

[0059] The sleeve 5 is positioned axially but can rotate freely on the connection support.

[0060] The sleeve 5 may comprise at least one window 6 to provide an indication of the positioning of the pipe and / or the crimping.

[0061] The coupling head 23 defines an internal housing 24 which houses the threaded insert 40, as can be seen in [Fig.3].

[0062] The threaded insert 40 is best seen in [Fig. 2]. The threaded insert 40 comprises an insert body 41 with an internal surface comprising a thread 60. A larger diameter insert head 43 is provided to hold the threaded insert 40 in the connector head 23. More specifically, the internal housing 24 is provided to hold the threaded insert 40 against radial movements and axial movements during connection. Therefore, the internal shape of the connector head 23 corresponds to the external shape of the insert head 43.

[0063] In other words, the insert head 43 is designed to be physically integrated into the connector head 23. This helps resist any internal force attempting to separate both the main connector body 10 and the threaded insert 40.

[0064] The threaded insert 40 is made of polymer or composite with a strength high wear resistance for connection to metal or polymer threaded fitting.

[0065] Figures 5 to 8 are examples of threaded insert 40 with different insert heads 43. The insert heads have an external shape that may include different bosses 46 distributed radially or axially along the external surfaces of the insert head 43.

[0066] A seal 50 is provided to bear against the enlarged end wall of the head portion at the axial end of the internal support below the connector head 23 and the insert 40.

[0067] The gasket 50 may have a circular, square, or rectangular cross-section. The gasket 50 is made of a material that provides sealing during a metal pipe connection without the need for Teflon or other types of sealing tapes or liquids.

[0068] As shown in [Fig.4], the connection head 23 can have different external connection shapes, corresponding to tools or facilitating the user's grip. This makes it possible to adapt to existing crimping tools. However, the threaded connection can also be made by hand, without requiring tools.

[0069] The connector body 1 is made of polymer to replace the brass or metal body of the prior art. As will be explained below with reference to [Fig. 14], the connector body 10 and the threaded insert 40 are bi-injected.

[0070] Figures 9 to 12 show another connector 201 according to another aspect of the disclosure. The connector is a male connector.

[0071] The connector 201 is a male connector, which may form one side of a connector having a similar or other type of connector at its other end or side. The connector may also be provided on a port of a fluidic device for connecting a hose thereto.

[0072] The mechanical connection 201 comprises a main connection body 210 intended to receive the pipe.

[0073] The main connector body 210 comprises an internal support 215 and a connector head 223. The internal support 215 extends between a free end of the support 213 and the connector head 223 whose diameter is greater than the internal support 215.

[0074] The inner support 215 is similar to the connector support of the first embodiment, and a sleeve, not shown, is provided to surround the inner support, for crimping the pipe end to the inner support. The inner support has a radial recess extending along the outer surface of the inner support, for crimping the pipe.

[0075] A circular channel 225 is provided between a radial fold 222 projecting radially outwardly from the internal support and the connecting head 223. The radial fold 222 allows the sleeve to be held, with or without an intermediate insert.

[0076] As shown in [Fig.l 1], the connector head 223 can have different external connector shapes, corresponding to tools or facilitating the user's grip. This makes it possible to adapt to existing crimping tools. However, as will be explained below, the threaded connection can also be made by hand, without the need for tools.

[0077] The main fitting body 210 is adapted to receive the pipe in the pipe insertion space on one axial side, and a threaded insert 240 on the other axial side for threaded connection with another pipe or fitting.

[0078] The coupling head 223 defines an internal housing 224 which houses the threaded insert 240.

[0079] The threaded insert 240 has an insert body 241 that extends axially between a free insert end and an enlarged insert head 243 of larger diameter.

[0080] The insert body 241 has an outer surface provided with a thread 260. The outer circumference of the insert body may also receive a seal. The inner circumference 242 of the insert body is flared, the inner diameter decreasing towards the insert head 243. The inclined surface allows a smooth transition between differences in diameter.

[0081] The larger diameter insert head 243 is provided to hold the threaded insert 240 in the connector head 223. More specifically, the connector head 223 defines an insert housing 224 for holding the threaded insert 240 against radial movement and axial movement of the threaded portion. Therefore, the internal shape of the internal housing 224 of the connector head 223 corresponds to the external shape of the insert head 243.

[0082] The insert head 243 is designed to physically integrate into the connector head 223 to resist any internal forces attempting to separate both the main connector body 210 and the threaded insert 240.

[0083] The threaded insert 240 is made of polymer or composite with high wear resistance for connection to the metal or polymer threaded fitting.

[0084] The insert housing 224 is provided between the enlarged head inner wall 245 extending radially from the inner support 15 and an extension 246 projecting radially toward the center. The extension 246 serves to support and hold the threaded insert 240 against axial movement during connection.

[0085] A seal housing 249 for housing a seal 250, which abuts the extension 246, on the axial outer wall 247 of the extension opposite the insert housing 224. It should be noted that the seal housing 249 is adapted to meet the seal 250 on an axial side and on a radial outer surface to prevent seal expansion and water loss due to internal pressure.

[0086] The gasket 250 is provided, which may have a circular, square or rectangular cross-section. The gasket 250 is made of a material that provides sealing when connecting metal piping without the need for Teflon or other types of tapes.

[0087] [Fig. 12] gives examples of threaded insert 240 with different insert heads 243. The insert heads have an external shape which may have different shapes 46 distributed radially or axially along the external surfaces of the head portion 243.

[0088] The connector body is made of polymer and replaces the brass or metal body of the prior art.

[0089] According to the present disclosure, the connector body 215 and the threaded insert 240 may be bi-injected or overmolded together.

[0090] In particular, the material of the main connector body 210 and the threaded insert 240 may be chosen to create a physicochemical bond during injection processes.

[0091] The physicochemical bond between the main connection body 210 and the threaded insert 240 creates the seal. It is therefore not necessary to provide a rubber seal between the main connection body 210 and the threaded insert 240.

[0092] The flexible hose is crimped onto the connector bracket 215 at one end, to connect the hose to the threaded connection on the other side.

[0093] On the threaded connection side, the thread 260 may be a metal thread or a polymer thread.

[0094] Like the connector body 1, the connector body 201 is made of polymer to replace the brass or metal body of the prior art.

[0095] It will now be explained which materials and why the fitting body 10 and the threaded insert 40 are bi-injected, with reference to [Fig. 14].

[0096] It should be understood that for portable, hot and cold pressurized water applications, the crimping technology for connecting a flexible hose via a polymer fitting requires specific material behavior of the fitting. The fitting must be strong enough not to collapse under crimping force, but also flexible to withstand significant deformation without premature failure. This is not a problem when considering a prior art brass or metal body.

[0097] The technical challenge arises when it comes to connecting a polymer thread to a metal thread. In order to be able to make a connection between a metal thread and high-tech polymers such as PPSU, PPA and PVDF, the connection material must have very high rigidity and very high mechanical strength.

[0098] The inventors have found a technical solution consisting of providing the main fitting body in a body material suitable for crimping, and providing a threaded insert in an insert material suitable for the threaded connection.

[0099] The body material for crimping must be flexible and withstand significant deformation without failure. In contrast, the threaded connection requires a harder, wear-resistant insert material.

[0100] By combining these two materials in a bi-injection process, it is possible to obtain a mechanical connection that exhibits both very flexible, ductile behavior, with high rigidity and high mechanical strength. These properties are achieved by at least two materials, a soft material for crimping that allows large deformations without failure, and a hard material for the threaded connection, which resists wear.

[0101] To manufacture a bi-material fitting, a first approach is overmolding. Usually, in the overmolding process, an additional mechanical integration between two materials is provided to prevent separation, or / and a chemical glue to create adhesion. In addition, a rubber gasket is required between the materials to ensure sealing and to compensate for different thermal expansion and shrinkage behaviors of the two materials.

[0102] According to the present disclosure, the inventors propose a bi-injection method which makes it possible to create the chemical bond between the fitting body and the threaded insert.

[0103] In particular, the materials of the main connector bodies 10, 210 and their threaded inserts 40, 240 may be chosen to create the chemical bond during the injection processes.

[0104] The physicochemical bond between the main connection body 10 and the threaded insert 40 creates the seal. It is therefore not necessary to provide an additional seal between the main connection body 10 and the threaded insert 40.

[0105] The flexible pipe, for example made of polymer, is crimped onto the connection support 15 at one end, to connect the pipe to the threaded connection on the other side.

[0106] On the threaded connection side, the thread 60 may be a metal thread or a polymer thread.

[0107] The method is described with reference to the mechanical connection of [Fig. 1].

[0108] In a first step S1, the insert material MI is injected into a rotary mold to manufacture the insert 40. Once the insert 40 has been injected, the material MB is injected onto the insert 40 in a second step S2, to manufacture the connector body 10.

[0109] Bi-injected materials are chosen to be compatible to join together.

[0110] The insert material and the fitting body material are chosen to accept a similar molding temperature range, as well as a close mold shrinkage percentage to avoid residual thermal stresses.

[0111] Similar molding temperature ranges mean that there must be an overlap between the molding temperature range of the fitting body material and the molding temperature range of the insert material.

[0112] A close mold shrinkage percentage to avoid residual thermal stresses means that the mold shrinkage percentage of the fitting body material and the mold shrinkage percentage of the material insert should not differ by more than 15%, preferably not more than 10%.

[0113] Since the main fitting body material is injected onto the insert 40 before the insert is cooled, the physicochemical bond can be created when the insert material and the fitting body material have a close melting temperature, with a similar or overlapping injection temperature range.

[0114] The bi-injection process makes it possible to create a physicochemical bond between the two materials, which is important for bonding the two materials against internal or external separation forces and sufficiently waterproof to prevent water leaks under high pressure and temperature.

[0115] Compatible materials are matrices of materials with their matrix reinforced, such as PVDF with PVDF+GF, or PPA with PPA+GF.

[0116] In another embodiment, compatible materials are a semi-crystalline polymer with its matrix at different crystallinity levels, such as polyethylene materials (LDPE, MDPE, HDPE or UHDPE) or a polyphenylene sulfone (PPSU) which is amorphous with a polyphenylene sulfide (PPS) which is semi-crystalline.

[0117] The fitting body material and insert material must be high-tech polymers compatible for contact with potable water and capable of withstanding the challenges of hot and cold pressurized applications.

[0118] First, on the crimping side, the fitting body material must be flexible enough to be crimped, but strong enough not to collapse and break. On the other hand, on the threaded fitting side, very high rigidity and high mechanical strength are required to support a threaded fitting, especially with a metal.

[0119] The first combination is a PPSU with PPS+GF. A PPSU is an amorphous polyphenylene sulfone, which is compatible with a PPS. A PPS is a semi-crystalline polyphenylene sulfide.

[0120] The inventors have discovered that the polymer combinations are preferably the following:

[0121] - PPSU is compatible with PPS, and can meet the requirements by combining PPSU + PPS GF (GF fiberglass content of 5 to 40%).

[0122] - PPA is compatible with PPA+GF (glass fiber content "GF" from 5 to 40%).

[0123] - PVDF is compatible with PVDF GF (5 to 40% "GF" glass fiber content).

[0124] It should be noted that the choice of material is not a simple design choice, but also provides other advantages: the mechanical fitting allows a secure connection with a pipe or with a threaded fitting made of metal or polymer, without intermediate material such as Teflon or similar products to ensure sealing. There is no need to chamfer the pipe or add sealing material to a threaded part of the fitting to ensure sealing.

[0125] The bi-injection process makes it possible to physically bond the external surface of the insert 40 to the internal surface of the main connector body 10. The head shapes with bosses act as additional anti-tear components.

[0126] The threaded portion of the fitting may be cylindrical or conical.

[0127] The bi-injection process has several advantages over other processes such as overmolding. Indeed, with the overmolding process, the insert 40 is first manufactured, then positioned in the mold for overmolding the insert.

[0128] The insert has time to cool before overmolding, which can prevent the formation of the physicochemical bond.

[0129] It is therefore necessary to add a seal to the insert to ensure sealing in the overmolding process.

[0130] The bi-injection process does not have these drawbacks. The heat of the insert after injection is sufficient to allow the creation of the physicochemical bond with the mechanical connection injected in a second step.

[0131] It is not necessary to perform pipe chamfering or to add a sealing material to a threaded portion of the fitting to ensure sealing. In addition, it is not necessary to provide a rubber gasket between the fitting body and the insert 40.

[0132] It should be noted that any type of threads can be considered, for example plastic or metal threads.

[0133] The seal can be assembled, but it is also possible to overmold or bi-inject the seal 50.

[0134] In summary, the present disclosure provides a mechanical fitting designed to establish a connection with a threaded fitting or pipe made of metal or polymer, without an intermediate material such as Teflon or similar products to ensure sealing. The fitting body is made of polymer to replace the brass or metal body. By providing an insert on the threaded connection side and by choosing compatible materials for both the fitting body and the insert, it is possible to achieve a physicochemical bond during injection processes, which makes it possible to achieve a leak-proof connection with threaded fittings made of metal or polymer that can be obtained.

Claims

Claims

1. A mechanical coupling for a crimping connection with a pipe on one side and for a threaded connection with another pipe or coupling on the other side, the mechanical coupling comprising: a main coupling body (10), having an internal support (15) for the crimping connection, the internal support extending between a free end to a coupling head (23) of a diameter greater than the internal support (15), a threaded insert (40) on the other axial side for the threaded connection with another pipe or coupling. wherein the threaded insert (40) is received in the coupling head (23), wherein the main coupling body is made of a polymeric coupling body material suitable for crimping and the threaded insert is made of a polymeric insert material suitable for the threaded connection, wherein the main coupling body and the threaded insert are bi-injected.

2. A mechanical connection according to claim 1, wherein the threaded insert (40) is integrated into the connection head.

3. A mechanical connection according to claim 1 or 2, wherein the threaded insert (40) has an insert body (41; 241), with a thread (60; 260) on an inner surface or an outer surface of the insert body, and an insert head (43; 243) of a diameter greater than the insert body (41; 241).

4. A mechanical connection according to claim 3, wherein the connection head (23; 223) has an internal housing (24) for receiving the insert head, the internal shape of the housing (24) of the connection head (23) corresponding to an external shape of the insert head (43).

5. A mechanical connection according to claim 4, wherein the insert head has an external shape with a plurality of bosses (46) distributed radially and / or axially along the external surfaces of the insert head.

6. A mechanical connection according to one of claims 4 or 5, wherein the insert housing (224) is provided between an enlarged head inner wall (245) of the connection head (223) extending radially from the inner support (215) and an extension (246) projecting radially inwardly.

7. A mechanical connection according to claim 6, wherein a seal housing (249) is provided within the connection head, for housing a seal (250) in abutment against the extension (246), on an axial external wall (247) of the extension opposite the insert housing (224).

8. A mechanical fitting according to any preceding claim, wherein the body material and the insert material meet at least one of the following criteria: the body material and the insert material have overlapping molding temperature ranges, the mold shrinkage percentage of the fitting body material and the mold shrinkage percentage of the insert material differ by less than 15%, preferably by less than 10%.

9. A mechanical connection according to claim 8, wherein the body material is PPSU, and the insert material is fiber-reinforced PPS, in particular with 5 to 40% glass fibers.

10. A mechanical connection according to claim 8, wherein the body material is PPA, and the insert material is fiber-reinforced PPA, in particular with 5 to 40% glass fibers.

11. A mechanical connection according to claim 8, wherein the body material is PVDF, and the insert material is fiber-reinforced PVDF, in particular with 5 to 40% glass fibers.

12. A method of manufacturing a mechanical fitting for a crimp connection with a pipe on one side and for a threaded connection with another pipe or fitting on the other side according to any one of claims 1 to 11, comprising injecting the insert material (MI) into a rotary mold to manufacture the insert (40), once the insert is injected, injecting the body material MB onto the insert (40), the method comprising forming a chemical bond between the insert and the fitting body.

13. The method of claim 12, wherein the MB body material is injected onto the insert less than five seconds after completion of the insert, the body material and the insert material having overlapping molding temperature ranges.

14. A method according to one of claims 12 or 13, wherein the body material is PPSU, and the insert material is fiber-reinforced PPS, in particular with 5 to 40% glass fibers, or the body material is PPA, and the insert material is fiber-reinforced PPA, in particular with 5 to 40% glass fibers, or the body material is PVDF, and the insert material is fiber-reinforced PVDF, in particular with 5 to 40% glass fibers.

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