Tubular junction comprising a seal with locking inserts which are fastened as a result of complementing shapes

Abstract

A tubular junction (10) comprising: - an end piece (12) defining a central axis (X) and a housing (14), - a spigot end (16) adapted to be inserted into the housing, - a seal (18) comprising a sealing body (38) made of elastic material, and locking inserts (36) distributed angularly about the axis. Each of the inserts comprises a head (42), and a body (44) extending obliquely relative to the axis between the head and the spigot end and forming one or more teeth for biting into the spigot end, each of the inserts being adapted for bracing between a groove (24) and the spigot end in order to prevent uncoupling of the spigot end. The inserts are at least partially overmoulded by the sealing body and have a hollow (50) or a protuberance (76) adapted to fasten each of the inserts to the sealing body as a result of complementing shapes.

Description

[0001] Tubular joint comprising a sealing gasket with locking inserts fixed by form-fitting

[0002] Field of invention

[0003] The present invention relates to a tubular junction comprising:

[0004] - a fitting end defining a central axis and a housing,

[0005] - a plain end adapted to be inserted into the housing along the central axis to achieve a nested position relative to the nested end, and

[0006] - a seal located radially relative to the central axis between the plain end and the socket end when the plain end is in the socketed position.

[0007] Such a joint is suitable, for example, for connecting two tubular elements of a drinking water, industrial water or wastewater pipeline. The tubular elements are, for example, pipes to be joined or a pipe and a fitting to be joined.

[0008] State of the art

[0009] The seal generally comprises a sealing body made of elastic material, for example elastomeric material, arranged around the central axis.

[0010] In order to prevent the spigot from coming loose, it is known to use a plurality of metal locking inserts distributed angularly around the central axis, between the spigot and the socket end, and defining teeth adapted to bite into the spigot. The metal locking inserts are advantageously fixed to the sealing body using an adhesive product, which makes it possible to easily arrange the sealing body and the locking inserts in the housing before fitting, without the locking inserts becoming detached. The adhesive product acts as a kind of glue between the metal locking inserts and the elastic material. The adhesive product is not necessarily compatible with drinking water.

[0011] However, the locking inserts are often manufactured at one location, for example in a foundry, while the adhesive is produced at another location, for example a chemical plant, and the adhesive is applied to the locking inserts at yet another location. The adhered inserts are then overmolded with the elastic material at yet another location, for example a plant manufacturing elastomer products. The gaskets thus assembled, with their locking inserts, are then shipped to the foundry that manufactures the pipe elements to be assembled, so as to assemble all the elements necessary to make the tubular connection.

[0012] This type of tubular joint is entirely satisfactory in terms of its performance and ease of implementation. However, its production is complex from a logistical point of view, with the inserts and the adhesive product being shipped from their industrial production sites to a site where the adhesive is applied to the inserts, then the adhered inserts being shipped to the seal production site, and finally the seals fitted with locking inserts being shipped to the tubular element manufacturing site.

[0013] In addition, gaskets are generally recycled, particularly to recover the locking inserts, which are relatively expensive parts, and to process the elastic material. However, these recycling operations are also complex due to the adhesive product present on the inserts.

[0014] An aim of the invention is to propose an efficient, cost-competitive tubular junction which is easy to implement and whose production and / or recycling are also facilitated.

[0015] Summary of the invention

[0016] To this end, the invention relates to a tubular junction comprising:

[0017] - a fitting end defining a central axis and a housing,

[0018] - a plain end adapted to be inserted into the housing along the central axis to achieve a nested position relative to the nested end, and

[0019] - a seal located radially relative to the central axis between the plain end and the socket end when the plain end is in the socketed position, the seal comprising:

[0020] - a sealing body of resilient material extending around the central axis and being at least partially located in an annular groove defined by the spigot end, the sealing body comprising a radially compressed portion between the plain end and the spigot end when the plain end is in the spigoted position, and

[0021] - a plurality of locking inserts distributed angularly around the central axis, each of the locking inserts comprising:

[0022] - a head located in the throat, and

[0023] - a body extending obliquely relative to the central axis between the head and the plain end and having a radially inner end, on the side opposite the head, forming one or more teeth adapted to bite into the plain end, each of the locking inserts being adapted to brace between the groove and the plain end to prevent disengagement of the plain end relative to the socket end, each of the locking inserts being at least partly overmolded by the sealing body, and defining at least one recess or comprising at least one protrusion, the recess or protrusion being adapted to fix each of the locking inserts on the sealing body by form-fitting.

[0024] According to other advantageous aspects of the invention, the tubular junction comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0025] - the sealing gasket is devoid of an adhesive layer applied to each of the locking inserts;

[0026] - each of the locking inserts is fixed to the sealing body only by form complementarity;

[0027] - each of the locking inserts defines at least two through-recesses extending in the circumferential direction around the central axis and filled by the sealing body;

[0028] - each of the locking inserts defines at least four blind holes extending in the circumferential direction, two of the four blind holes being defined by a first surface of each of the locking inserts, and two other of the four blind holes being defined by a second surface of each of the locking inserts, the second surface being opposite the first surface in the circumferential direction, two of the four blind holes being respectively opposite two other of the four blind holes in the circumferential direction, the four blind holes being filled by the sealing body;

[0029] - each of the locking inserts defines at least four circumferentially extending protrusions, two of the four protrusions being defined by a first surface of each of the locking inserts, and two other of the four protrusions being defined by a second surface of each of the locking inserts, the second surface being opposite the first surface in the circumferential direction, two of the four protrusions being respectively opposite two other of the four protrusions in the circumferential direction, the four protrusions being embedded in the sealing body; - the body of each of the locking inserts comprises a radially outer surface, said surface defining either a rail or a “T” groove, the rail or the groove extending in the circumferential direction, the sealing body filling the groove or overmolding the rail;

[0030] - each of the locking inserts defines at least one through-housing extending in a radial plane relative to the central axis;

[0031] - the through-housing extends between two surfaces of the body of each of the locking inserts, the two surfaces being radially opposed to each other; and

[0032] - the through housing opens onto a radially outer surface defined by the head of each of the locking inserts, said surface being opposite a bottom of the groove.

[0033] Figures

[0034] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawings, in which:

[0035] - figure 1 is a schematic view, in section along a radial plane, of a tubular junction according to the invention,

[0036] - Figure 2 is a perspective view of a locking insert shown in Figure 1, and

[0037] - Figures 3 to 8 are perspective views of locking inserts, respectively according to a first variant, a second variant, a third variant, a fourth variant, a fifth variant and a sixth variant of the locking insert shown in Figures 1 and 2.

[0038] Tubular junction

[0039] With reference to FIG. 1, a tubular junction 10 according to the invention is described.

[0040] The tubular joint 10 comprises a spigot end 12 defining a central axis X and a housing 14, and a plain end 16 adapted to be inserted into the housing along the central axis X to achieve a nested position relative to the spigot end. The tubular joint 10 comprises a seal 18 located, radially relative to the central axis X, between the plain end 16 and the spigot end 12 when the plain end is in the nested position. The tubular joint 10 is for example buried in a ground 20. The plain end 16 is part of an element 16A such as a pipe and the spigot end 12 is part of an element 12A such as a pipe or a fitting. The elements 16A, 12A are themselves part of a pipeline 22 or a pipeline system (not shown), and are for example suitable for conveying or storing drinking water, industrial water or waste water. The plain end 16 and the socket end 12 are advantageously made of cast iron.

[0041] The nested position is visible in Figure 1.

[0042] A non-nested position, in which the spigot 16 is away from the spigot end 12, is not shown but is easily deduced from the nested position by offsetting the spigot to the left relative to the spigot end in Figure 1.

[0043] The spigot end 12 defines an annular groove 24 adapted to receive the seal 18.

[0044] In the example, the socket end 12 is in one piece.

[0045] According to a variant (not shown), the interlocking end 12 comprises several parts, for example a body and an end part (axially on the side of the plain end) fixed to the body in the interlocked position, for example by means of fixing flanges, and receiving the plain end 16 in the interlocked position.

[0046] The housing 14 is advantageously axisymmetrical around the central axis X and for example defined by a flared part 26 of the interlocking end 12.

[0047] The groove 24 opens radially into the housing 14. The groove is for example delimited axially by two surfaces 28, 30 axially opposite one another. The groove 24 has for example two cylindrical bottoms 32, 34 around the central axis X.

[0048] In the example, the two surfaces 28, 30 diverge towards the central axis X, and form two angles a and p with the central axis X advantageously between 70° and 90°.

[0049] The bottom 32 is for example further from the central axis X than the bottom 34, and located on the side of the plain end 16 relative to the bottom 34. The bottom 32 is radially opposite a plurality of locking inserts 36 (only one of which is shown in FIG. 1) of the sealing gasket 18.

[0050] Sealing gasket

[0051] The sealing gasket 18 comprises a sealing body 38 made of elastic material, extending around the central axis X and at least partially located in the annular groove 24. Such a material is flexible or resilient. This material is sometimes referred to as “hyperelastic”, i.e. having great elasticity. It is, for example, a synthetic or natural elastomer. The sealing gasket 18 is advantageously constituted solely by the sealing body 38 and the plurality of locking inserts 36. In particular, the sealing gasket 18 is advantageously devoid of an adhesion layer which would be applied to each of the locking inserts 36 to fix them to the elastic material.

[0052] The sealing body 38 is for example in contact with the surface 28 and the two bottoms 32, 34 which partly delimit the groove 24.

[0053] The sealing body 38 is advantageously made of elastomer material, for example NBR rubber (acrylonitrile-butadiene rubber; in English: Nitrile Butadiene Rubber) or EPDM (Ethylene-propylene-diene monomer).

[0054] The sealing body 38 has a portion 40 compressed radially between the plain end 16 and the spigot end 12 when the plain end is in the spigoted position. In the example, the portion 40 in question is compressed between the bottom 34 and the plain end 16.

[0055] Locking inserts

[0056] The locking inserts 36 are distributed angularly around the central axis X, advantageously regularly. Their number depends on the nominal diameter of the tubular elements to be assembled.

[0057] The locking inserts 36 are advantageously similar to each other, so only one of them will be described below with reference to Figures 1 and 2.

[0058] The locking insert 36 comprises a head 42 located in the groove 24, and a body 44 extending obliquely relative to the central axis X between the head and the plain end 16. The locking insert 36 is advantageously delimited in the circumferential direction (around the central axis X) by a first surface 46 and a second surface 48 oriented radially or parallel to each other.

[0059] Each of the locking inserts 36 is adapted to buttress between the groove 24 and the spigot end 16 to prevent disengagement of the spigot end from the socket end 12.

[0060] The locking inserts 36 are made of a material of greater hardness than the spigot material and are preferably made of metal, for example stainless steel.

[0061] The locking insert 36 is at least partly overmolded by the sealing body 38, and defines at least one hollow 50 adapted to fix the locking insert 36 on the sealing body 38 by form complementarity. The form complementarity is advantageously the only means of fixing the locking insert 36 on the sealing body 38. Optionally, the locking insert 36 forms a constriction 52 between the head 42 and the body 44, but which is not in the example sufficient to ensure fixing by form complementarity.

[0062] In the example shown in Figures 1 and 2, the locking insert 36 defines two through-receiving housings 54A, 54B extending in the circumferential direction around the central axis X, for example substantially perpendicular to the first surface 46 and to the second surface 48. The two through-receiving housings 54A, 54B are filled with the elastic material of the sealing body 38. At least one of the two through-receiving housings 54A, 54B forms the hollow 50.

[0063] According to a variant not shown, the locking insert 36 defines more than two through housings, for example three.

[0064] The body 44 has a radially inner end 56, on the side opposite the head 42, forming one or more teeth 58 adapted to bite into the plain end 16. In section along a radial plane (plane of FIG. 1), the body 44 defines for example an angle y with the head 42.

[0065] In the example, the head 42 and the body 44, with the exception of the teeth 58, are completely overmolded by the sealing body 38.

[0066] The head 42 defines a front surface 60 (axially on the side of the plain end 16) intended to be substantially parallel to the surface 28 when the locking insert 36 is braced, the head 42 also abutting against the bottom 32 of the groove 24.

[0067] The teeth 58 are for example four in number. The teeth 58 are advantageously arranged successively along a convex curve C, the convexity of which is turned towards the plain end 16, so that forces F of the locking insert 36 on the plain end 16 are concentrated on a subgroup of the teeth 58, for example on two of the teeth.

[0068] One of the two through housings 54A, 54B is located for example in the head 42.

[0069] The other of the two through housings 54A, 54B is located for example in the body 44, or at the junction between the body 44 and the head 42.

[0070] The two through-housings 54A, 54B are for example cylindrical. They have the same diameter D1 advantageously between 2 and 5 mm.

[0071] The two through housings 54A, 54B allow for more metal material to be placed in the axis of the compressive forces exerted on the insert 36, compared to a single wider housing. This allows for better resistance to the compressive forces generated by the wedge effect locking, and reduces the risk of fracturing the inserts. First variant

[0072] Referring to Figure 3, a locking insert 36A is described according to a first variant. The locking insert 36A is analogous to the locking insert 36 shown in Figures 1 and 2. Similar elements have the same reference numerals and will not be described again. Only the differences will be described in detail below.

[0073] The locking insert 36A does not define the two through-recesses 54A, 54B.

[0074] The locking insert 36A defines four blind holes 62A, 62B, 62C, 62D extending in the circumferential direction, for example substantially perpendicular to the first surface 46 and the second surface 48. At least one of the four blind holes forms the recess 50.

[0075] In variants not shown, the locking insert 36A defines more than four blind holes.

[0076] The blind holes 62A, 62C are defined by the first surface 46, and the blind holes 62B, 62D are defined by the second surface 48.

[0077] The blind holes 62A, 62C are respectively opposite the blind holes 62B, 62D in the circumferential direction.

[0078] The four blind holes 62A, 62B, 62C, 62D are filled with the elastic material of the sealing body 38.

[0079] The four blind holes 62A, 62B, 62C, 62D are for example cylindrical and advantageously have the same diameter D2 equal to the diameter D1.

[0080] The blind holes 62A, 62B, 62C, 62D have for example a depth H1 (in the circumferential direction) between 2 and 5 mm.

[0081] The two blind holes 62A, 62B are located for example in the head 42.

[0082] The two blind holes 62C, 62D are located for example in the body 44, or at the junction between the body and the head.

[0083] In the example, the four blind holes 62A, 62B, 62C, 62D can be considered as being initial parts (closest to the surface of the locking insert) of the through housings 54A, 54B of the locking insert 36. In other words, the locking insert 36A is deduced from the locking insert 36 by obstructing a central part (in the circumferential direction) of the through housings 54A, 54B.

[0084] Second variant

[0085] Referring to Figure 4, a locking insert 36B is described according to a second variant. The locking insert 36B is analogous to the locking insert 36A shown in Figure 3. Similar elements have the same reference numerals and will not be described again. Only the differences will be described in detail below.

[0086] The locking insert 36B does not form a recess 50, but at least one protrusion 76.

[0087] The locking insert 36B does not define four blind holes, but four protrusions 64A, 64B, 64C, 64D for example located at the same locations as the blind holes of the locking insert 36A. At least one of the protrusions 64A to 64D forms the protrusion 76.

[0088] According to variants not shown, the locking insert 36B defines more than four protrusions.

[0089] The four protrusions 64A, 64B, 64C, 64D are inserted into the sealing body 38.

[0090] The two protrusions 64A, 64C are defined by the first surface 46, and the other two protrusions 64B, 64D are defined by the second surface 48.

[0091] The four protrusions 64A, 64B, 64C, 64D are for example cylindrical and advantageously have a diameter D3 equal to the diameter D2. The protrusions 64A, 64B, 64C, 64D have for example the same length H2 (in the circumferential direction) equal to the depth H1.

[0092] In the example, the four protrusions 64A, 64B, 64C, 64D can be considered as being the "negatives" (or mirror images) of the blind holes 62A, 62B, 62C, 62D.

[0093] Third variant

[0094] Referring to Figure 5, a locking insert 36C is described according to a third variant. The locking insert 36C is analogous to the locking insert 36 shown in Figures 1 and 2. Similar elements have the same reference numerals and will not be described again. Only the differences will be described in detail below.

[0095] The locking insert 36C does not define the two through-recesses 54A, 54B.

[0096] The body 44 of the locking insert 36C includes a radially outer surface 66 forming a back.

[0097] The surface 66 defines at least one “T” shaped groove 68 forming the depression 50. The groove 68 extends in the circumferential direction.

[0098] Due to its “T” shape, the groove 68 defines a housing 70 whose entrance is formed by two lips 72 facing each other. The elastic material of the body 38 fills the groove 68.

[0099] Fourth variant

[0100] Referring to Figure 6, a locking insert 36D is described according to a fourth variant. The locking insert 36D is analogous to the locking insert 36C shown in Figure 5. Similar elements have the same reference numerals and will not be described again. Only the differences will be described in detail below.

[0101] The locking insert 36D does not define a groove 68, but at least one “T” rail 74 located at the same location as the groove 68 and forming the protrusion 76.

[0102] Rail 74 extends in the circumferential direction.

[0103] The sealing body 38 overmoulds the rail 74.

[0104] Fifth variant

[0105] Referring to Figure 7, a locking insert 36E is described according to a fifth variant. The locking insert 36E is analogous to the locking insert 36 shown in Figures 1 and 2. Similar elements have the same reference numerals and will not be described again. Only the differences will be described in detail below.

[0106] The locking insert 36E does not define the two through-housings 54A, 54B, but at least one through-housing 78 extending in a radial plane P relative to the central axis X. The through-housing 78 defines the recess 50.

[0107] Compared to a circumferentially oriented through-housing or blind hole, orientation in a radial plane has the advantage of reducing mechanical stresses within the 36E locking insert by reducing the internal surfaces subject to bending moment created by bracing.

[0108] The through housing 78 extends between two surfaces 66, 80 of the body 44 opposite each other radially.

[0109] Sixth variant

[0110] Referring to Figure 8, a locking insert 36F is described according to a sixth variant. The locking insert 36F is analogous to the locking insert 36E shown in Figure 7. Similar elements have the same reference numerals and will not be described again. Only the differences will be described in detail below.

[0111] The through housing 78 does not extend between the two radially opposite surfaces 66, 80 of the body 44.

[0112] The through housing 78 opens on the one hand onto a radially external surface 82 defined by the head 42 and located opposite the bottom 32 of the groove 24. The through housing 78 opens on the other hand onto the front surface 60.

[0113] Common points of certain variants

[0114] As can be seen above, in the locking inserts 36, 36A, 36B, 36C, 36D, the recess 50 (for example formed by the two through-recesses 54A, 54B, the four blind holes 62A to 62D, or the groove 68), or the protrusion 76 (for example formed by the four protrusions 64A to 64D, or the rail 74) advantageously extend in the circumferential direction around the central axis X.

[0115] In the locking inserts 36, 36A, 36C, the recess 50 is for example formed by a through housing, a blind hole or a groove.

[0116] In the locking inserts 36B and 36D, the protrusion 76 is for example formed by a conventional protrusion in itself, such as the protrusion 64A, or by a more complex protrusion, such as the rail 74.

[0117] The circumferential orientation of the recesses or protrusions provides better resistance of the inserts 36 to the shear forces exerted on the rubber during the deformation of the seal 18 for its installation in the socket end 12 and during the insertion of the plain end 16 into the socket end, thus allowing a stronger connection between the inserts and the rubber which surrounds them.

[0118] Combination of the previous variants

[0119] It should be noted that the above locking insert variants 36, 36A to 36F are optionally combinable with each other, i.e. the recesses and / or protrusions of these variants can be added to each other.

[0120] Thanks to the features described above, the tubular joint 10 is efficient and has a competitive cost. The tubular joint 10 is easy to implement, since the seal 18 is easily installed, the locking inserts 36, 36A to 36F being correctly fixed on the sealing body 38. The production and recycling of the tubular joint 10 are also facilitated.

Claims

CLAIMS 1. Tubular junction (10) comprising: - a fitting end (12) defining a central axis (X) and a housing (14), - a plain end (16) adapted to be inserted into the housing (14) along the central axis (X) to reach a nested position relative to the nested end (12), and - a seal (18) located radially relative to the central axis (X) between the plain end (16) and the socket end (12) when the plain end (16) is in the socketed position, the seal (18) comprising: - a sealing body (38) made of elastic material extending around the central axis (X) and being at least partially located in an annular groove (24) defined by the interlocking end (12), the sealing body (38) comprising a portion (40) compressed radially between the plain end (16) and the interlocking end (12) when the plain end (16) is in the interlocked position, and - a plurality of locking inserts (36; 36A to 36F) distributed angularly around the central axis (X), each of the locking inserts (36; 36A to 36F) comprising: - a head (42) located in the throat (24), and - a body (44) extending obliquely relative to the central axis (X) between the head (42) and the plain end (16) and having a radially inner end (56), on the side opposite the head (42), forming one or more teeth (58) adapted to bite into the plain end (16), each of the locking inserts (36; 36A to 36F) being adapted to brace between the groove (24) and the plain end (16) to prevent the plain end (16) from disengaging from the interlocking end (12), each of the locking inserts (36; 36A to 36F) being at least partly overmolded by the sealing body (38), and defining at least one recess (50) or comprising at least one protuberance (76), the recess (50) or the protuberance (76) being adapted to fix each of the locking inserts (36; 36A to 36F) on the sealing body (38) by form complementarity.

2. Tubular junction (10) according to claim 1, in which the sealing gasket (18) is devoid of an adhesion layer applied to each of the locking inserts (36; 36A to 36F).

3. Tubular junction (10) according to claim 1 or 2, in which each of the locking inserts (36; 36A to 36F) is fixed on the sealing body (38) solely by form complementarity.

4. Tubular junction (10) according to any one of claims 1 to 3, in which each of the locking inserts (36) defines at least two through housings (54A, 54B) extending in the circumferential direction around the central axis (X) and filled by the sealing body (38).

5. Tubular joint (10) according to any one of claims 1 to 3, wherein each of the locking inserts (36A) defines at least four blind holes (62A, 62B, 62C, 62D) extending in the circumferential direction, two of the four blind holes (62A, 62B, 62C, 62D) being defined by a first surface (46) of each of the locking inserts (36A), and two others of the four blind holes (62A, 62B, 62C, 62D) being defined by a second surface (48) of each of the locking inserts (36A), the second surface (48) being opposite the first surface (46) in the circumferential direction, two of the four blind holes (62A, 62B, 62C, 62D) being respectively opposite two others of the four holes blind holes (62A, 62B, 62C, 62D) in the circumferential direction, the four blind holes (62A, 62B, 62C, 62D) being filled by the sealing body (38).

6. Tubular joint (10) according to any one of claims 1 to 3, wherein each of the locking inserts (36B) defines at least four circumferentially extending protrusions (64A, 64B, 64C, 64D), two of the four protrusions (64A, 64B, 64C, 64D) being defined by a first surface (46) of each of the locking inserts (36B), and two other of the four protrusions (64A, 64B, 64C, 64D) being defined by a second surface (48) of each of the locking inserts (36B), the second surface (48) being opposite the first surface (46) in the circumferential direction, two of the four protrusions (64A, 64B, 64C, 64D) being respectively opposite two other of the four protrusions (64A, 64B, 64C, 64D) in the circumferential direction, the four protrusions (64A, 64B, 64C, 64D) being inserted into the sealing body (38).

7. Tubular junction (10) according to any one of claims 1 to 6, wherein the body (44) of each of the locking inserts (36C; 36D) comprises a radially outer surface (66), said surface (66) defining one or the other of a rail (74) or a “T” groove (68), the rail (74) or the groove (68) extending in the circumferential direction, the sealing body (38) filling the groove (68) or overmolding the rail (74).

8. Tubular junction (10) according to any one of claims 1 to 7, in which each of the locking inserts (36E; 36F) defines at least one through housing (78) extending in a radial plane (P) relative to the central axis (X).

9. Tubular junction (10) according to claim 8, in which the through housing (78) extends between two surfaces (66, 80) of the body (44) of each of the locking inserts (36E), the two surfaces (66, 80) being radially opposite each other.

10. Tubular junction (10) according to claim 8, in which the through housing (78) opens onto a radially outer surface (82) defined by the head (42) of each of the locking inserts (36F), said surface (82) being opposite a bottom (32) of the groove (24).

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