FR2775506A1 - Quick-fit joint especially for plastic tubes with insert and locking nut - Google Patents

Abstract

The joint consists of a body (1) designed to be mounted on a component to which the tube (T) is to be connected, and a locking nut (S) which is rotated about to its own lengthwise axis (X-X). The cavity (6) of the body and the locking nut aperture (12) lie eccentrically in relation to the nut's axis, and the body has a stop (5) which fixes the position of the locking nut relative to the body with the eccentricity of the cavity and aperture sufficient to grip the tube. In a second position there is a sufficient gap for the tube to be inserted or removed.

Description

QUICK TIGHTENING CONNECTION FOR TUBES, PARTICULARLY FOR PLASTIC TUBES, AND MANUFACTURING METHOD
WITH SUCH A CONNECTION.

 The invention relates to a quick clamping connector for tubes, a connector of the kind which comprises - a body to be mounted on a member to be connected to a tube, this body comprising a housing for receiving one end of the tube - and a clamping means. of the tube, rotatably mounted on the body about a geometric axis of rotation, this clamping means comprising an opening for the passage of the tube.

 The tube to be connected can be made of any material, for example metal or plastic, but the invention relates more particularly to the case of a plastic tube.

 The object of the invention is, above all, to provide a fitting which, while being simple to produce and quick to implement, allows effective clamping and blocking of the tube.

According to the invention, a quick-tightening connector of the kind defined above is characterized in that: - the housing of the body and the opening of the tightening means are eccentric with respect to the geometric axis of rotation of the tightening means - a stop means is provided to stop the clamping means from rotating relative to the body in a first angular position where there is, between the housing and the opening, an eccentricity sufficient for blocking the tube,
the assembly being such that in a second relative angular position of the body and of the clamping means, angularly distant from the first position, the eccentricity between the housing and the opening is sufficiently reduced to allow the introduction of the tube into the housing through the opening.

 The perimeter of the contour formed by the intersecting internal arcs of the opening and of the housing, in the first angular position, is less than the external circumference of the tube.

 The housing and the opening have, in general, a circular cross section of the same diameter, except for manufacturing tolerances. Preferably the housing and the opening have the same absolute offset value.

 According to an advantageous solution, in the second relative angular position of the body and the clamping means, the housing and the opening are opposite one another, their axes being aligned, and the eccentricity between the housing and the opening is reduced to zero.

 The second angular position can be angularly distant by 180 from the first position.

 The eccentricities of the housing and the opening are preferably diametrically opposite in the first angular position.

 The clamping means may include a nut cooperating with an external thread provided on the body. The abutment means can then be formed by a front end of the body capable of coming to bear in the axial direction against a transverse wall of the nut.

 According to another possibility, the clamping means is constituted by a ring mounted to rotate on one end of the body, and stopped axially by retaining means.

 These retaining means may include, on the body, an external peripheral groove, and, on the ring, a bore of axis orthogonal to that of the ring opening in the groove and a pin engaged in the bore and cooperating with the throat. The stop means for stopping the ring relative to the body in the first angular position, ensuring the blocking of the tube, can be formed by a projection provided in the groove. A second projection can be provided in the groove to determine the second angular position of the ring relative to the body allowing the introduction of the tube into the fitting.

 The connector may comprise, in particular in the case of a plastic tube, a metallic tubular insert intended to be placed inside the end of the tube engaged in the connector.

 A sealing means is provided and advantageously comprises an O-ring disposed in an internal groove of the housing of the body, at an axial distance from the clamping means sufficient so that the surface of the tube, in line with the joint, is not too deformed.

 The invention also relates to a method of manufacturing a fitting as defined above, characterized by the following steps - a body blank without housing and a clamping means blank without opening are prepared, with means of stop - the blanks of the body and of the clamping means are assembled until they come into abutment in the first relative angular position - the blank of the clamping means is turned relative to that of the body, in the opposite direction to that which caused the abutment, by an angle at most equal to 1800 from the abutment position - and the opening is drilled in the blank of clamping means, and the housing in the body blank along a common axis , offset transversely relative to the geometric axis of rotation of the clamping means relative to the body.

 Preferably, the two blanks are rotated by 1800 relative to one another, from the stop position to make the drilling.

 The invention consists, apart from the arrangements set out above, of a certain number of other arrangements which will be more explicitly discussed below in connection with embodiments described with reference to the attached drawings, but which are in no way limiting.

 Figure 1 of these drawings is an axial longitudinal section of a connector according to the invention, the clamping means and the body being in the second relative angular position allowing the insertion of the tube.

 Figure 2 shows, similarly to Figure 1, the connection with the clamping means in abutment against the body in the first angular position ensuring the blocking of the tube in the connection.

 Figure 3 is a left view with respect to Figure 2, without the tube, of the intersecting internal contours of the opening and the housing.

 Figure 4 is an exterior view of the connector of Figure 2.

 Figure 5 is an axial section of blanks of the body and the clamping means, in the relative angular position of Figure 1, for drilling the housing in the body, and the opening in the clamping means.

 Figure 6 is an axial longitudinal section of a variant, in the second angular position.

 Figure 7 is a view on the left with respect to Figure 6, with parts broken away.

Figure 8, at the end, is a view similar to the
Figure 7, but for the first angular position of the connector.

Referring to the drawings, in particular to
Figures 1 and 2, we can see a quick-tight fitting R for a tube T which, in the example shown, is made of plastic, for example polyethylene, crosslinked polyethylene, polypropylene, polyvinyl chloride, polyamide. The tube T can however be made of any material, in particular metal, in particular copper, galvanized steel, stainless steel, brass.

 The connector R comprises a body 1 to be mounted on a member (not shown in Figs.l and 2) to be connected to the tube T. The body 1 has a generally cylindrical outer shape of revolution around an axis X-X. The part of the body 1 situated on the side opposite to the tube T comprises an external thread 2, of axis X-X, allowing the fixing of the body 1 by screwing in a tapped hole of the member to be connected. The body 1 comprises, substantially in the length, on its outer wall, a shoulder 3 with a hexagonal prismatic outer surface (or with a hexagon).

The end of the body 1 turned towards the tube T has, on its outer surface, a thread 4 also of axis
XX. The body 1 ends in a front wall 5 facing the tube T.

 A housing 6, formed by a bore, is provided in the body 1 to receive an end T1 of the tube.

The housing 6 is limited, on the side of the end remote from the front wall 5, by a shoulder 7 projecting radially inwards and surrounding an opening O. The internal diameter of the housing 6 is slightly greater than the external diameter of the tube T which can thus be engaged with reduced play in this housing 6.

 A clamping means S of the tube T is rotatably mounted on the body 1. The clamping means S can rotate about an axis of rotation formed by the geometric axis XX of the body 1. This axis XX is also that of the surface outside of the clamping means S.

 The clamping means S is advantageously constituted by a hexagonal nut 8 comprising a thread 9 which is screwed onto the thread 4 of the body 1. A rotary movement of the nut 8 relative to the body 1 is accompanied by an axial displacement relative. Alternatively (see Figs. 6 to 8) the clamping means S can be constituted by a ring mounted to rotate on the body 1, and stopped axially by retaining means.

 The internal thread 9 is centered on the X-X axis, like the thread 4.

 The nut 8 is provided with an internal cylindrical surface 10, centered on the axis XX, suitable for cooperating with a cylindrical surface 11 provided on the body 1 between the front end 5 and the thread 4. This surface 11 is also centered on the XX axis. The cooperation of the bearing surfaces 10 and 11 ensures precise guidance of the nut 8 relative to the body 1.

 The clamping means S has a circular opening 12 for the passage of the tube T. The diameter of this opening 12 is, apart from the clearance, the outside diameter of the tube T.

 A sealing means D is provided in the body 1 to establish a seal between this body and the tube T.

This sealing means D is formed by an O-ring 13 housed in an internal groove 14 of the body 1. The groove 14 is provided axially substantially at mid-length of the shoulder 3.

 Generally, in the case of a plastic tube T, a metallic tubular insert 15, in particular brass or copper, is provided to be engaged with gentle friction in one end T1 of the tube introduced into the fitting. A part of the insert 15 remains outside the tube T and ends in a flared end 16 which is stopped by the shoulder 7.

The outside diameter of the insert 15 is equal to the tolerances close to the inside diameter of the tube T.

 According to the invention, the housing 6 of the body 1, and the opening 12 of the nut 8 are eccentric relative to the geometric axis X-X of rotation of the nut.

Preferably, the housing 6 and the opening 12 have a circular cross section of the same diameter, and the same absolute offset value e
In the relative angular position of the body 1 and the nut 8 shown in Figure 1, the housing 6 and the opening 12 are opposite one another, their geometric axes being aligned and coincident with the axis
AA. This axis AA is offset radially from the eccentricity e with respect to the geometric axis XX of rotation. In the position of FIG. 1, the opening 12 is concentric with the housing 6 and the tube T can be inserted by sliding into the housing 6.

 The front wall 5 constitutes an axial abutment means, suitable for stopping the nut 8 in rotation, relative to the body 1, in a first angular position shown in FIG. 2. The assembly is provided so that, in this position, a sufficient offset E exists between the housing 6 and the opening 12 to ensure that the tube T is blocked in the fitting. This abutment position is determined by the front wall 5 which comes to bear, in the axial direction, against a transverse wall 17 of the nut 8.

 Preferably, in the first angular position of Figure 2, the eccentricities of the housing 6 and the opening 12 are diametrically opposite, so as to add. Thus, the eccentricity E is equal to twice the elementary eccentricity e of the body and the nut.

Figure 3 shows the outline of the housing 6 and the opening 12, in the relative position of the
Figure 2. The center B1 of the contour 6 is located above the axis XX, by a distance equal to the eccentricity e of the housing 6 relative to the axis XX.

 The center B2 of the opening 12 is located below the axis X-X at a distance equal to the eccentricity e of this opening relative to the geometric axis X-X of the nut.

 Although it is preferable to provide equal eccentricities e for the nut and the body, it would be possible to provide slightly different eccentricities.

The perimeter imposed on the tube T at the limit of the opening 12 and of the housing 6 is represented by a contour 18 in thicker lines, in FIG. 3, formed by the two intersecting internal arcs of the bore 6 and of the opening 12. The perimeter of the contour 18 is less than the circumference of the tube T so as to tighten the tube. The degree of tightness can be assessed by the diameter (less than the outside diameter of the tube
T) of a circumference equivalent to the contour 18, that is to say having the same length as the perimeter of this contour.

 The relative angular position of the body 1 and of the nut 8 illustrated in FIG. 1 corresponds to a second angular position angularly distant by 1800 from the first position illustrated in FIG. 2.

In Figure 2, the front wall 5 is in axial abutment against the transverse wall 17. In Figure 1, an interval i exists between these two walls and corresponds to a half-pitch of the thread 4. In the position of Figure 1 , the center B2 of the opening 12 (see Fig. 3) coincides with the center B1 of the housing 6 so that the eccentricity of the opening 12 relative to the housing 6 is reduced to zero, allowing the introduction of tube T in the housing.

 The implementation of the connector according to the invention results from the foregoing explanations. The body 1 is mounted by screwing its part 2 on the member to be connected.

 Before the insert 15 and the tube T are introduced into the housing 6, the nut 8 is screwed until it abuts by its wall 17 against the front end 5 of the body 1, in the relative position illustrated on Figure 2.

 The nut 8 is then unscrewed by a half-turn which brings it into the relative position of FIG. 1 where the opening 12 is concentric with the housing 6.

 The tube T, optionally fitted with the insert 15, is introduced into the housing 6 through the opening 12. The tube T is engaged enough so that the seal 13 bears on the outside surface of the tube.

 The nut 8 is then rotated in the tightening direction until it comes to a stop in the first angular position illustrated in FIG. 2.

The relative eccentricity between the opening 12 and the housing 6 is then maximum. Tube cooperation
T with the contour 18 ensures the locking of the tube T in the fitting. Depending on the extent of the eccentricity, a slight deformation of the wall of the tube T and of the insert 15 may occur. This deformation has been shown strongly accentuated in Figure 2 to better understand the operation.

 It should be noted that the groove 14 and the seal 13 are sufficiently distant axially from the front end 5 so that the part of the tube with which the seal 13 cooperates is not too deformed.

 Installation at the connector is therefore extremely simple and rapid, since it only takes half a turn of the nut to ensure locking.

By way of nonlimiting example, for a tube T with an external diameter equal to 16 mm, a fitting has been produced in which the bores 6 and 12 have a diameter of 16.1 mm with each an eccentricity e = 0.6 mm , which gives a tight fitting to 15.3 mm (diameter of the equivalent circumference, defined previously)
To manufacture a fitting R, we can operate as follows.

 A blank (Fig. 5) of body without housing is prepared and a blank 8a of nut without opening.

 The two blanks are assembled by screwing the tapped part 9 of the nut blank onto the thread 4 until it is blocked by coming into abutment of the front end 5 against the front wall 17.

 Then the nut blank 8a is unscrewed relative to the body blank 1a at an angle equal to 1800 from the stop position.

 Then drilled with a drill or a reamer F the opening 12 and the housing 6 along a common axis A-A radially offset from the eccentricity e with respect to the geometric axis X-X of the blanks la and 8a.

 We finish by making at the bottom of the housing 6 the opening O bordered by the shoulder 7.

 Although the offset of 1800 between the second angular position and the first angular stop position is preferred, this offset could be less than 1800.

 Referring to Figures 6 to 8, we can see an alternative embodiment R1 of the connector according to the invention. Elements similar to those already described with respect to the preceding Figures will be designated by numerical references equal to the sum of the number 100 and the numerical reference used previously, without their description being repeated in detail.

The connector R1 does not have a thread on the body 101 and the clamping means S. In addition, the connector R1 is provided for connecting two tubes T and Tb. The tube Tb constitutes the member, mentioned above, on which R1 is mounted
The body 101 consists of a metallic cylindrical sleeve, of circular cross section centered on the axis XX. The sleeve 101 has a bore 106, of geometric axis AA, offset from the value e with respect to the axis XX. The eccentricity e is of the order of 0.9 mm.

 In the embodiment considered, the two tubes T, Tb joined by R1 have the same outside diameter. As a result, the fitting R1 as a whole is symmetrical with respect to an average mediating plane M orthogonal to the axis X. Only the left part of FIG. 6 will be described, the right part deducing therefrom with the same references. Of course, the connector could be provided for assembling tubes of different diameters, in which case there would no longer be complete symmetry.

 At mid-length, the bore 106 has an internal radial shoulder 107 serving as a stop to limit the introduction of the tube T or Tb. Two annular grooves 114 are provided, in the bore 106, on either side of the shoulder 107, to respectively receive an O-ring 113.

A clamping means S is provided on each longitudinal end of the body 101. The clamping means
S is constituted by a ring 108 whose outer surface 19 is cylindrical of revolution around a geometric axis coincident with the axis AA in the position shown in FIG. 6. The ring 108 is rotatably mounted on one end of the body 101.

 With plastic tubes T, Tb, the tightening torques to be brought into play are relatively low, so that the tightening can be carried out manually, without using a wrench. Under these conditions, the outer surface 19 of the ring 108 can be smooth, or if necessary knurled. Optionally, if it is desired to leave a possibility of using a key, gripping means, such as two diametrically opposite flats, can be provided on this surface 19.

 The ring 108 has a bore 109 coaxial with the external surface 19, and the internal diameter of which is equal, apart from the operating clearance, to the external diameter of the body 101. One end of the body 101 is engaged in the bore 109. A transverse wall 117, forming a shoulder, limits this bore 109 inwards.

 The opening 112 in the ring 108 follows the bore 109 and opens on the side opposite the body 101.

This opening 112, of circular shape, is eccentric relative to the external surface 19 and to the bore 109. In the example shown, the eccentricity of the opening 112 is also equal to e and, in FIG. 6, l aperture 112 is centered on the axis AA.

 Retaining means for axially stopping the ring 108 relative to the body 101 are provided.

 These retaining means comprise, on the side of the sleeve 101, a peripheral groove 20 provided on the outer surface of the sleeve 101 in the vicinity of each of its ends. The groove 20, the mean plane of which is orthogonal to the axis of the sleeve 101, has a semicircular section turning its concavity towards the outside. On the side of the ring 108, the retaining means comprise a pin 21 engaged in a hole 22 made in the ring 108. The axis of the hole 22 is located in a plane orthogonal to the geometric axis of the ring 108, substantially at mid-length of bore 109. The bore 22 has substantially the same diameter as the groove 20, opens in the groove 20 and is tangent to the bottom of this groove.

The pin 21, when placed in this bore 22, partially engages in the groove 20, being tangent to the bottom of this groove. The ring 108 can thus rotate freely relative to the body 101. The pin 21 moves in the groove 20 and, by cooperating with this groove, retains the ring 108 axially relative to the body 101.

 The stop means 105 for stopping in rotation the ring 108, relative to the body 101, in the first angular locking position (illustrated in FIG. 8), is formed by a substantially prismatic triangular projection in the groove 20. This stop 105 can be made by a weld deposit obstructing the groove 20 at the appropriate location.

 By rotating the ring 108 clockwise, relative to the body 101, from the position of FIG. 7, the pin 21 can be brought to bear against the stop 105 which prevents any additional rotation. The relative position then obtained is that of FIG. 8, for which the eccentricity of the opening 112 is diametrically opposite to that of the bore 106.

Preferably, a second stop 23 is provided in the groove 20 to stop the pin 21 and the ring 108 in the second angular position, illustrated on
Figs. 6 and 7. The opening 112 is then opposite the bore 106, which makes it possible to introduce the tube T. The stop 23 is produced in a similar manner to the stop 105 and is placed so that the two positions of the ring 108 are approximately 1800 apart.

 It is clear that the stop 23 is not essential, but makes it possible to very easily identify the alignment position of the opening 112 and the bore 106.

 The pin 21 is held in its bore 22 by any suitable means, for example by stamping the ends of the bore or by gluing.

The installation of tube T in the fitting of
Figs. 6 to 8 follows from the foregoing explanations.

 The operator grasps the body 101 with one hand and, with the other hand, rotates the ring 108, located on the left in FIG. 6, to bring it into abutment in the second position (position in FIG. 7) .

 The tube T is introduced into the fitting, until it abuts axially against the shoulder 107. The operator, while holding the body 101, then rotates the ring 108 in the clockwise direction according to Fig. 7, to bring the pin 21 against the stop 105 (Fig.8).

 The operator can, in general, dispense with using a wrench for tightening a plastic tube T, especially in the case where no metal insert is introduced into the tube T, because the operation does not require too high a drive torque.

 The installation of the other tube Tb in the right end of the fitting R1 is carried out in a similar manner.

 The manufacture of the connector R1 can take place in the same manner as that described in connection with FIG. 5, that is to say that, in the relative position of FIG. 6, the opening 112 and the bore 106 are drilled along the common axis AA.

 The fittings according to the invention are particularly suitable for plastic pipes, in particular crosslinked polyethylene, with an outside diameter which can vary from 6 mm to 200 mm.

 A connector according to the invention can be used to connect pipes of the same diameter or of different diameters, made of identical or different materials. The fittings according to the invention can be union fittings, elbows, tees, or other usual shapes.

Claims (17)

 CLAIMS 1. Quick-fitting coupling for tubes, comprising - a body (1,101) to be mounted on a member to be connected to a tube (T), this body comprising a housing (6,106) to receive one end of the tube - and a means of clamping (S) of the tube, rotatably mounted on the body about a geometric axis of rotation (XX), this clamping means comprising an opening (12,112) for the passage of the tube, characterized in that: - the housing ( 6.106) of the body and the opening (12.112) of the clamping means are eccentric relative to the geometric axis of rotation (XX) of the clamping means (S) - a stop means (5.105) is provided to stop in rotation the clamping means (S) relative to the body in a first angular position where there is, between the housing (6,106) and the opening (12,112), an eccentricity (E) sufficient for blocking the tube, the assembly being such that in a second relative angular position of the body and the clamping means, angular distance In the first position, the eccentricity between the housing (6,106) and the opening (12,112) is reduced enough to allow the introduction of the tube (T) into the housing through the opening. 2. Connection according to claim 1, characterized in that the perimeter of the contour (18,118) formed by the intersecting internal arcs of the opening (12,112) and the housing (6,106), in the first angular position, is less than the outer circumference of the tube (T). 3. Connection according to claim 1 or 2, characterized in that the housing (6,106) and the opening (12,112) have a circular cross section of the same diameter. 4. Connection according to one of the preceding claims, characterized in that the housing (6,106) and the opening (12,112) have the same absolute offset value (e). 5. Connection according to claim 4, characterized in that, in the second relative angular position of the body and the clamping means, the housing (6,106) and the opening (12,112) are opposite one another , their axes being aligned (AA), and the eccentricity between the housing and the opening is reduced to a zero value. 6. Connection according to one of the preceding claims, characterized in that the second angular position is angularly distant by 1800 from the first position. 7. Connection according to claim 6, characterized in that the eccentricities of the housing (6,106) and the opening (12,112) are diametrically opposite in the first angular position. 8. Connection according to one of the preceding claims, characterized in that the clamping means (S) comprises a nut (8) cooperating with an external thread (4) provided on the body (l). 9. Connection according to claim 8, characterized in that the stop means is formed by a front end (5) of the body clean to come to bear in the axial direction against a transverse wall (17) of one nut. 10. Connection according to one of claims 1 to 7, characterized in that the clamping means (S) consists of a ring (108) rotatably mounted on one end of the body (101) and stopped axially by means of restraint (20,21,22). 11. Connection according to claim 10, characterized in that the retaining means (20,21,22) comprise, on the body (101), an external peripheral groove (20), and, on the ring (108), a bore (22) of axis orthogonal to that of the ring and opening in the groove (20), and a pin (21) engaged in the bore and cooperating with the groove (20). 12. Connection according to claim 11, characterized in that the stop means (105) for stopping the ring (108) relative to the body (101) in the first angular position, ensuring the blocking of the tube, is formed by a projection (105) provided in the groove. 13. Connection according to claim 12, characterized in that a second projection (23) is provided in the groove (20) to determine the second angular position of the ring (108) relative to the body (101) allowing the introduction of the tube in the fitting. 14. Connection according to one of the preceding claims, characterized in that it comprises, in particular in the case of a plastic tube, a metallic tubular insert (15) placed inside the end (T1) of the tube engaged in the fitting. 15. Connection according to one of the preceding claims, characterized in that a sealing means (D) is provided and comprises an O-ring (13,113) disposed in an internal groove (14,114) of the housing of the body, at a axial distance from the clamping means sufficient so that the surface of the tube, in line with the joint, is not excessively deformed. 16. A method of manufacturing a fitting according to claim 5, characterized by the following steps - a blank (the) of body without housing and a blank (8a) of clamping means without opening, with means of preparation, are prepared. stop - the blanks of the body and of the clamping means are assembled until they come into abutment in the first relative angular position - the blank of the clamping means is turned relative to that of the body, in the opposite direction to that which caused the abutment, at an angle at most equal to 180 ° from the abutment position - and the opening is pierced in the clamping means blank and the housing in the body blank along a common axis ( AA), offset transversely relative to the geometric axis of rotation (XX) of the clamping means relative to the body. 17. The method of claim 16, characterized in that the two blanks are rotated by 180C relative to each other, from the stop position to perform the drilling.