FR2775330A1 - Rapid connection of thermoplastic tube carrying fluid to mount, used in hydraulic or pneumatic circuits - Google Patents

Abstract

The unit (100) allows the quick connection of two tubes (41a,41b) for the transmission of a fluid (44) contained in a body (106). An inclined anchorage blade (112) has a fixed part to the body and free ends (78a,78b) which extend into the passageways into which are inserted the tubes. Plungers (70a,70b) are provided in the body to bend the ends of the anchorage blade out of the way for the insertion of the tubes into their respective holes (80a,80b) where the ends are sealed by O-rings (62a,62b). On release of the plungers, the free ends of the anchorage blade dig into the walls of the tubes to anchor them in position.

Description

QUICK CONNECTION DEVICE
TUBE IN THERMOPLASTICS
The invention relates to a quick connection device for a thermoplastic tube intended to convey air or fluids under pressure, the device being used in particular in pneumatic or hydraulic circuits.

 A pneumatic system generally comprises at least one control element and a pneumatic or electropneumatic receiver and a tube (or pipe) connecting the control element to the receiver. The pneumatic control systems operate with a gas in a closed circuit without leakage and consequently any pressure exerted on the control element is transmitted to the entire pneumatic system and in particular to the pneumatic receiver.

 The control element can be a pneumatic push button which when actuated by an operator generates pressure in a compression chamber of the button. The pressure in the compression chamber will be transmitted to the receiver through the tube. This pressure will be transformed in the receiver for example into a mechanical movement actuating an electrical contact.

 The pneumatic system can be more or less complex depending on the applications and can include different control elements connected by several tubes and fluid distributors to several receivers such as pneumatic or electro-pneumatic amplifiers.

In the same way, these considerations are applicable to hydraulic circuits
Among the main characteristics of a pneumatic or hydraulic system is the reliability of operation of the system which depends inter alia on its tightness at least during the appearance of pressure in the elements of the system filled with fluid.

 In order to ensure reliable operation of the system, the tubes transmitting this pressure must be connected to the various elements of the system in a safe and sealed manner.

 Another important characteristic of a system operating by the pressure transmitted by a fluid in a sealed circuit, resides in the ease and speed of assembly or modification of the system. In particular, the connection of the tubes to the various elements of the system must be able to be carried out without difficulty and in a safe and reliable manner.

 Currently there are quick couplings for tube which allow a reliable and rapid assembly or disassembly of the tube on a support provided for this purpose.

 Figure 1 shows a partial section of an example of a quick connector currently on the market.

 A quick connector 10 is mounted in the body 14 of a fluid distributor 20, the body 14 having an internal face 16 and an external face 18, the internal face is in contact with the fluid and the external face subjected to the ambient pressure. The pressure transmitted by the fluid 20 appears from the side of the internal face 16 of the distributor producing a displacement of the fluid 20 in a tube 22, shown in dotted lines in FIG. 1, inserted in the fitting 10.

 The quick connector 10, of circular cylindrical shape along an axis of revolution X'X comprises a socket 24 in the form of a tube. The sleeve is housed clamped in a first cavity 26, circular cylindrical, produced in the body 14 and coaxial with the axis X'X.

 A clamp 28 of circular cylindrical shape mounted coaxially inside the sleeve 24, allows the tightening of the tube 22 inserted in the quick connector.

 The internal diameter of the sleeve 24 gradually increases at its lower part creating a slope producing a tightening effect on the grooved lower part of the clamp 28. This tightening effect maintains the tube 22 in the quick connector 10 during a traction to extract the tube from the fitting or when pressurizing the fluid 20 in the tube.

 The seal between the body and the tube inserted in the fitting is ensured by an O-ring 30 enclosing the tube 22, the O-ring being located in a second circular cylindrical cavity 32 coaxial with the axis X'X opening onto the first cavity 26.

 A first passage 34 opening through the internal face 16 of the body of the distributor, of diameter slightly smaller than the diameter of the tube 22, followed by a second passage 36 of a diameter allowing the insertion of the tube 22 into the body 14 and opening into the second cavity 32 ensures the passage of the fluid in the tube 22.

 The implantation of such a quick connector according to the state of the art requires the production in the support of a first cavity 26 allowing the insertion of the connector into the body, of a diameter much larger than the diameter of the tube to insert into the fitting.

 Today, all the quick couplings existing on the market require for their installation in different supports a certain space, for example, for tubes having respectively external diameters of 4 mm., 6 mm. and 8 mm., cavities with diameters of 8.3 mm and 10.3 mm are required respectively. and 12.3 mm. etc.

 Today, the flow performance of distributors is such that the flow at the distributor outlet is limited by the size of the fittings.

 In fact, in a distributor with a width of 10 mm., The flow rate of which can be greater than 400 liters per minute, one can only install quick couplings for tubes whose outside diameter does not exceed 6 mm. A 4 mm tube. does not allow a flow rate substantially equal to 250 liters per minute to be exceeded, which represents a limitation of the flow rate at the outlet of the distributor.

 Even by eliminating the socket and using another system which retains the clamp by an intermediate piece, the installation of a quick coupling supporting a tube with an outside diameter of 6 mm, leads to a minimum support (or body) width 10 mm.

 The present invention overcomes the drawbacks of the prior art by proposing a device for quick connection of one or two tubes intended to transmit a fluid contained in a body, characterized in that it comprises a hooking blade inclined in a rest position relative to the axis of revolution of a tube, the blade having a fixed end relative to the body and one or two free ends, each free end of the blade obstructing the passage of a tube before l insertion of the tube into the body and being able to be driven out by the tube when it is inserted into the body, each free end of the blade tending to sink into a tube when it is pulled towards the outside of the body, each end free of the blade tending to take a more inclined position relative to the axis of a tube during such traction so as to oppose this traction.

 A first advantage of the quick connection device according to the invention, compared to the quick couplings of the prior art, lies in the possibility of being able to mount tubes of larger diameter for the same width of the support (or body). Indeed, in the case of a distributor having 10 mm. wide, it is possible to install a quick coupling device according to the invention, allowing the insertion of a tube having an outside diameter of 8 mm. allowing access to flow rates greater than 400 liters per minute at the outlet of the distributor. The connection device no longer limits the distributor's own capacity.

 Another advantage of the invention consists in the possibility offered by the connection device of being able to integrate an element for releasing the tube in the body and thus of being able to easily carry out its extraction from the body. Indeed, a tensile force exerted on the tube and the simultaneous action on the release element are sufficient to remove the tube from the body, the operation of inserting or extracting the tube from the body can thus be repeated as many times as necessary.

In an embodiment of the quick coupling according to the invention, for a single tube, the body has a first opening ensuring the passage of the tube in the body, a hooking blade having a single free end, a second opening allowing it to be driven out by bending , using a rod or a pusher, the free end of the attachment blade, releasing the tube,
The free end of the blade no longer being in contact with the outside surface of the tube.

 In another embodiment of the quick connector for two tubes, the body has two first openings ensuring the passage of a first and a second tube in the body, a fastening blade having two free ends, two second openings for hunting by bending, using a rod or a pusher for each of the second openings, each of the two free ends of the attachment blade respectively releasing the first and the second tube, each of the two free ends of the blade hooking no longer being respectively in contact with the outer surface of the first and second tubes.

 The connection device further comprises means ensuring the sealing of each of the tubes of the ambient medium, for example an O-ring placed in the body and enclosing a tube.

Other characteristics and advantages of the invention will appear on reading the descriptions of examples of embodiment of the quick coupling device according to the invention in which
- Figure 1 already described shows a partial section of a quick connector according to the prior art;
- Figures 2a, 2b, 2c and 2d show a device for quick connection of a tube, according to the invention;
- Figures 3a and 3b show a quick coupling device of two tubes, according to the invention.

 FIG. 4 shows a metal tube intended for producing the device of FIG. 2a.

 Figures 2a and 2b show a section of a quick connection device 40 of a thermoplastic tube 41 implanted along an axis of insertion Y'Y, merging with the axis of revolution of the tube, in the body 42 d 'a fluid dispenser 44 and Figure 2c a top view of the same device of Figure 2a.

 The body 42 of the dispenser has an internal surface 46 in contact with a fluid 44, and external surfaces at the pressure of the ambient medium.

 Among the external surfaces, a first surface 48 and a second surface 50, these two surfaces being perpendicular to the insertion axis Y'Y, mutually parallel and located at two different levels, the second surface 50 being closer to the internal surface 46 of the body 42.

 The first surface 48 is connected to the second surface 50 by a protuberance 52 of the body and a third surface 54 perpendicular to the second surface 50. The first 48, second 50 and third 54 surfaces and the protrusion 52 form a step whose edge constituted by the protrusion 52 rises above the level of the first surface 48.

 A first passage 56 opening on the one hand through the internal surface 46 of the body 42 ensures the passage of the fluid 44 in the tube 41 for connecting the distributor, this first passage 56 opening on the other hand on a second passage 58 of a diameter allowing the insertion of the tube 41 into the body 42.

 On the side of the second surface 50 of the body 42, the second passage 58 widens in the form of a circular cylindrical recess 60, coaxial with the insertion axis YY 'opening onto the second surface 50 of the body 42.

 The recess 60 comprises an O-ring 62 enclosing the tube 41 and ensuring the tightness of the tube and of the body with respect to the ambient medium. The O-ring 62 is compressed between a retaining ring 64 housed in the recess 60 and a connection surface 66 resulting from the widening of the second passage 58 leading to the recess 60. The ring 64 is held in the recess 60 by a closure piece 66 of the body 42 of the dispenser.

 The third surface 54 perpendicular to the second surface 50 is located at a distance D from the external surface of the tube 41 showing a first cavity 68 for the passage of a pusher 70 and a hooking blade 72.

 The attachment blade 72 is in the form of a V having two branches of different lengths, a first branch 74 and a second longer branch 76 joining on the top of the V. The attachment blade is positioned and maintained by sandwiching the first branch 74 of the blade, between the closing part 66 of the distributor body and the protuberance 52 of the body, so that the second longer branch 76 penetrates freely into the first cavity 68. The second branch 76 of the hooking blade 72 presses, by its free end 78, the outer surface of the tube 41 at an angle al relative to the insertion axis Y'Y of the tube such that the free end 78 of the second branch 74 of the attachment blade 72 is located lower than the top of the V formed by the attachment blade.

 The introduction of the tube 41 into the quick connector 40 causes the second free branch 76 of the hooking blade 72 to bend down its free end 78 down (ie towards the second surface 50), accompanying the movement of the tube until its insertion into the second passage 58.

 When the tube 41 is in place in the connection device, a pull of the tube or the pressure of the fluid 44 tending to extract it from the body of the distributor tends to push the free end 78 of the hooking blade 72 into the surface outside of the tube. Indeed, the free end 78 of the hooking blade in contact with the tube is pulled by the tube towards the outside of the body, which tends to increase the inclination (angle a 1) of the second free branch of the attachment blade with respect to the axis of insertion Y'Y of the tube opposing the extraction of the tube and consequently ensuring that it is held in position in the connection device 40.

 The closing part 66 of the body has a first opening 80 for the passage of the tube 41 and a second opening 82 for the passage of an external part 84 of the pusher 70 allowing the hooking blade 72 to be actuated for the release of the tube .

 An inner part 86 of the pusher 70 can slide parallel to the insertion axis Y'Y in a second cavity 88 of the closure part 66. The second cavity 88 is located substantially in the extension of the first cavity 68 in which is located finds the hooking blade 72.

 FIG. 2b shows the connection device when the pusher 70 is actuated to extract the tube 41. For this purpose a pressure P is exerted on the top of the outer part 84 of the pusher 70. The interior part 88 of the pusher while moving towards the inside of the first cavity 68 causes the second free branch 76 of the hooking blade to bend 72 releasing its free end 78 from the outside surface of the tube 41. In this position the second branch 76 of the hanging blade is inclined by a new angle a2, relative to the axis of insertion Y'Y of the tube, smaller than the angle al, when the tube is in the locked position.

 The disengagement of the blade from the external surface of the tube releases the latter which can then be extracted from the quick coupling 40 by a pull T pulling it outwards from the body 42.

 Once the tube extracted from the quick connector, the release of the pressure P on the pusher 70 allows the hooking blade 72 to resume an initial shape before the insertion of the tube into the body, the second free branch 76 returning the pusher at an initial position close to that of FIG. 2a. The fitting is then ready for new use.

 The initial shape of the blade, before the introduction of the tube 41 into the body 42, corresponds to an initial inclination, of an angle a 0, of the second branch 76 of the hooking blade 72, slightly larger than the inclination, of angle al, when the tube is in the body. Indeed the attachment blade not being driven by the tube, take a rest position without bending.

Figure 2d shows the different positions taken by the hooking blade 72, before the insertion of the tube (angle a 0), when the tube is inserted in the body (angle a 1) and when the blade is actuated by the pusher 70 (angle a 2) in order to extract the tube from the body 42
In the following we will describe another embodiment of a quick connection device according to the invention, allowing the connection of two thermoplastic tubes.

 FIG. 3a represents a section of a quick connection device 100 of two tubes and FIG. 3b a top view of this device.

 The quick connection device 100 comprises a first quick connection device 102a for a first tube 41a and a second quick connection device 102b for a second tube 41b, the second device being symmetrical with respect to the first device with respect to a plane S of symmetry. In this embodiment, the attachment blade has two free ends intended respectively for holding the first and second tubes in position.

 The two connection devices 102a and 102b are mounted in a single body 106 comprising, as in the case of the device in FIG. 2a, an internal surface 46 in contact with the fluid 44 and external surfaces at the pressure of the ambient medium.

 Among the external surfaces of the second surfaces 50a and 50b and of the third surfaces 54a and 54b perpendicular to the second surfaces 50a and 50b. The third surfaces 54a and 54b are connected symmetrically with respect to the plane S by a fourth surface 108, the third surfaces 54a, 54b and the fourth surface 108 forming a bump 110 in the body 106 above the third surfaces 54a and 54b, the hump 110 ensuring the maintenance and positioning in the body of an attachment blade 112 comprising two second free branches 76a and 76b symmetrical with respect to the plane S of symmetry and freely penetrating into the first cavities 68a and 68b. To this end, the attachment blade 112 is sandwiched at a fixed central part of the blade, between the hump 110 and a double closure piece 108.

 Two first cavities 68a and 68b are formed respectively in the first device 102a and in the second device 102b. One of the first two cavities 68a is formed essentially by the external surface of the first tube 41a, one of the second surfaces 50a and one of the respective third surfaces 54a au of the first device 102a, and the other of the first two cavities 68b being formed essentially by the external surface of the second tube 41b, the other second surface 50b and the other third surface 54b respective to the second device 102b.

 In the same way as for the embodiment of the quick coupling device of FIG. 2a, the connecting device 100 comprises first passages 56a and 56b followed respectively by the second passages 58a and 58b ensuring the passage of the fluid 44 respectively in the first tube 41a and in the second tube 41b. Each of the second passages 58a and 58b widening in the form of cavities 60a and 60b each comprising an O-ring 62a and 62b and a retaining ring 64a and 64b, each of the O-rings ensuring respectively the seal with respect to the ambient environment of the first tube 41 a and second tube 41 b.

 FIG. 3a shows the first tube 41a of the first device 10a blocked by one of the two second free branches 76a of the attachment blade 112 penetrating into the first cavities 68a of the first device 102a, the pusher 70a of this first device being at rest, and the second tube 41b of the second device 102b in a free being allowing its release from the body 106, the pusher 70b being actuated by a pressure Pb exerted on its upper part 84b moving it towards the second cavity 68b respective to its device 102b.

 The retaining rings 64a and 64b are held in their respective cavities 60a and 60b by a double piece of closure 108 of the body of the distributor 106.

 The tube used in the various quick connection devices is made of thermoplastic material, for example polyurethane or polyamide, and allows the attachment of the end of the attachment blade to the exterior surface of the tube.

 The tube can also be made of a harder material, for example metal. In this case the tube has a groove allowing a free end engagement of the hooking blade in this groove, producing the blocking of the tube in the body.

 Figure 4 shows the blade of the embodiment of Figure 2a, and a metal tube 41c when the metal tube is inserted into the body 42 (not shown in Figure 4).

 A groove 120 produced on the entire periphery of the metal tube 41c is located in a plane perpendicular to the axis Y'Y of revolution of the tube and at the height of the free end 78 of the attachment blade 72 in contact with the tube. When the tube is in place in the quick coupling device, the free end of the hooking blade penetrates into the groove 120 preventing, as has been described above, the extraction of the tube.

Claims (10)

 1. Quick connection device (10,40,100) of one or two tubes (22,41,41a, 41b, 41c) intended to transmit a fluid (20,44) contained in a body (14,42,106), characterized in that it comprises a hooking blade (72,112) inclined in a rest position relative to the axis of revolution of a tube, the blade having a fixed part relative to the body and one or two free ends (78 , 78a, 78b), each free end of the blade obstructing the passage of a tube before the insertion of the tube into the body and being able to be driven out by the tube when it is inserted into the body, each free end of the blade tending to sink into a tube when it is pulled towards the outside of the body, each free end of the blade tending to assume a more inclined position relative to the axis of a tube during such traction so as to oppose this traction.  2. Connection device according to claim 1 characterized in that the connection device comprises means (62,64,62a, 64a, 62b, 64b) ensuring the tightness of the tubes of the ambient medium.  3. Connection device according to claim 2, characterized in that the sealing means comprise an O-ring (62, 62a, 62b) enclosing a tube.  4. Connection device according to claims 1 to 3, characterized in that the body has a first opening (80) ensuring the passage of a tube (41) in the body, a latching blade (72) having a single free end (78), a second opening (82) allowing it to be driven out by bending, using a rod or a pusher (70), The free end (78) of the attachment blade, releasing the tube (41), The free end of the blade no longer being in contact with the outside surface of the tube.  5. Connection device according to claim 4, characterized in that the body has a first cavity (68) for the passage of the pusher (70) and the free end of the latching blade (72).  6. Quick connection device according to claim 5, characterized in that the body (42) has an internal surface (46) in contact with a fluid (44), and external surfaces at the pressure of the ambient medium and among the surfaces external, a first surface (48) and a second surface (50), these two surfaces being perpendicular to an axis of insertion Y'Y of the tube, mutually parallel and located at two different levels, the second surface (50) being closer to the internal surface (46) of the body (42), the first surface (48) being connected to the second surface (50) by a projection (52) of the body and a third surface (54) perpendicular to the second surface (50), the first (48), second (50), third (54) surfaces and the protrusion (52) forming a step whose edge formed by the protrusion (52) rises above the level of the first surface (48), and in that the third surface (54) perpendicular to the s This second surface (50) is located at a distance D from the external surface of the tube (41) showing the first cavity (68) for the passage of the pusher (70) and the hooking blade (72).  7. Connection device according to claim 6, characterized in that the hooking blade (72) is in the form of a V having two branches of different lengths, a first branch (74) and a second branch ( 76) longer, the two branches joining on the top of the V, the attachment blade being positioned and held by the sandwiching of the first branch (74) of the blade, between a closing piece (66) of the body (42) the protuberance (52) of the body, so that the second longer branch (76) freely penetrates into the first cavity (68), the second branch (76) of the attachment blade (72) pressing by its free end (78) the outer surface of the tube (41) at an angle ai with respect to an axis of insertion Y'Y of the tube such that the free end (78) of the second branch (74) of the attachment blade (72) is located lower than the top (70) of the V formed by the attachment blade.  8. Connection device according to one of claims 1 to 3, characterized in that the body (78a, 78b) has two first openings (80a, 80b) ensuring the passage of a first (41a) and a second tube (41b) in the body (106), a hooking blade (112) comprising two free ends (78a, 78b), two second openings (82a, 82b) allowing hunting by bending, using a rod or pusher (70a, 70b) for each of the second openings, each of the two free ends (78a, 78b) of the hooking blade (112), releasing respectively the first (41a) and the second tube (41b ), each of the two free ends of the attachment blade no longer being respectively in contact with the outer surface of the first and second tubes.  9. Connection device according to claim 8, characterized in that it comprises an internal surface (46) in contact with the fluid (44) and external surfaces at the pressure of the ambient medium and among the external surfaces of the second surfaces ( 50a, 50b) and third surfaces (54a, 54b) perpendicular to the second surfaces (50a, 50b), the third surfaces (54a, 54b) being connected symmetrically with respect to a plane S by a fourth surface (108), the third surfaces (54a, 54b) and the fourth surface (108) forming a bump (110) in the body (106) above the third surfaces (54a, 54b), ia bump (110) ensuring the maintenance and positioning in the body of the attachment blade (112) comprising two second free branches (76a, 76b) symmetrical with respect to the plane S of symmetry and freely penetrating into first cavities (68a, 68b), the attachment blade (112) being sandwiched at a fixed central part of the blade between the hump (110) and a double closing piece (108), two first cavities (68a, 68b) being formed respectively in a first device (102a) and in a second device (102b), one of the two first cavities (68a) being formed essentially by the external surface of the first tube (41a), one of the second surfaces (50a) and one of the third surfaces (54a) respective to the first device (102a), and the other of the first two cavities (68b) being formed essentially by the external surface of the second tube (41b), The other second surface (50b) and the other third surface (54b) respective to the second device (102b).  10. Connection device according to claims 1 to 9, characterized in that the tube (41c) is made of metal and that it has a groove (120) formed over its entire periphery, the groove being located in a plane perpendicular to the axis of revolution of the tube and at the height of the free end (78) of the hooking blade (72) in contact with the tube, when the tube is in place in the connection device.