FR2735844A1 - Quick-fit joint for tube connected to rigid component - Google Patents

Abstract

The joint comprises a tubular insert (1) with external anchoring elements (7) for engaging with the inner surface (107) of a recess (105) in the rigid component (103), a retaining member for the tube (101) and a seal (25). The insert (1) has a nose (21) with an outer diameter smaller than that of the anchoring elements, and a guard ring (23) with an inner diameter similar to that of the nose, with the ring mounted on the free end of the latter and fixed axially by a locking member (27), with the seal (25) inside the ring. The guard ring locking member has a connecting zone of low mechanical strength, e.g. with a peripheral groove. The joint also has a tubular pusher (13) which slides inside the insert to control the release of the retaining member (11).

Description

 The present invention relates to a device for quick connection of a tube to a rigid element and more particularly to a device for quick connection of the "cartridge" type intended to anchor a tube in a bore of the rigid element (by example a pneumatic component body) as well as the tightness of the formed fitting.

 Quick connection devices are known which are intended to make the sealed connection of a tube in a stepped bore of a rigid element. In general, this type of device is in the form of a tubular insert comprising a tubular body having means for its permanent anchoring in the rigid element and means for retaining the tube. Most often, the anchoring means are produced in the form of fir teeth formed on the outer face of the tubular body and opposing the axial withdrawal of this body when the latter is introduced inside a first section of the bore of the rigid element. The tube retaining means can be produced in the form of a washer with internal toothing whose teeth are raised by bending during the introduction of the tube and tend to bite the tube to oppose its extraction, or in the form of a hooking ring comprising a plurality of longitudinal arms, the free ends of which have edges turned towards the external surface of the tube and cooperate by a cam surface with the body tubular to be tightened against the tube when pulled to be extracted. There may also exist between the tube and the body a sliding pusher to lift the teeth and allow the disconnection of the tube. Before mounting in the rigid element the connection device is in the form of a cartridge "that is that is to say that the insert is internally pre-equipped with the tube retaining means, and is mounted on the rigid element by simple force introduction into the stepped bore.

 The sealing of the fitting is ensured by means of a generally O-ring seal, housed in a second section of the bore of smaller diameter than the first section during the introduction of the tubular body inside. of the first section of the bore. In general, the bore has a third section, the diameter of which, even smaller than that of the second section, is close to the outside diameter of the tube and which is intended to receive the end of this tube to ensure its correct positioning.

 Currently, the installation of this device inside the bore is carried out by means of a specific mounting tool in the form of a tubular sleeve which forces the penetration of the tubular body into the bore. An elongate piece of revolution passes through the tubular body and has at one end a shoulder which bears against one end of the tubular body and at the other end has a groove in which the seal is housed. During assembly, when the tubular body is inserted inside the bore, the seal is housed in the second section of the bore and the elongated part is removed.

 However, during storage, transport and the various manipulations that the connection device undergoes before its assembly, the seal is not protected, risk of being damaged, or even escaping from the part which ensures its maintenance. . Similarly, during assembly, this seal, the outside diameter of which is greater than the diameter of the second section of the bore, rubs against the entry edge of this second section and thus risks being damaged again.

 It therefore appeared useful to design a quick connection device of the "cartridge" type having effective means of protecting the seal both before and during assembly.

 According to the invention, a device is provided for quick connection of a tube in the form of a cartridge insertable into a cylindrical housing, comprising a tubular insert having externally means for its anchoring in the housing and internally means for retaining the tube, and a seal, in which the tubular insert has a nose with an outer diameter smaller than that of the means for anchoring the tubular insert and a protective ring with an inner diameter close to the outside diameter of the nose, this ring being mounted on the free end of the nose and being immobilized axially relative to this nose by a low resistance locking means in an axially projecting position relative to this nose to internally receive the seal.

 Thus, before mounting, the seal is kept integral with the cartridge and is protected from possible external attack by the protective ring which surrounds it. During assembly, the tubular insert is introduced axially into a first section of the stepped bore. When the protective ring reaches the end of this first section, it abuts against a shoulder formed by a second section of the stepped bore of the rigid element. The locking means, which immobilized the ring relative to the nose, then gives way under the effect of the axial thrust force exerted on the tubular insert, so that the nose of the insert slides inside the ring and pushes the seal inside the second section of the bore of the rigid element. In this way, the seal, which is already compressed inside the protective ring so that its diameter outside is substantially close to the diameter of the second section of the bore, does not rub against the entry edge of this second section and therefore does not undergo any deterioration.

 According to an advantageous embodiment, the means for blocking the protective ring consists of a zone of connection of this protective ring to the nose which has low mechanical characteristics.

 As a variant, the means for blocking the protective ring consists of a connection zone by bonding this ring with the nose.

 According to another advantageous embodiment, the means for blocking the protective ring comprises an internal projection formed on the protective ring and cooperating with an associated peripheral groove of the nose.

 According to an advantageous characteristic of the invention, the protective ring has an outside diameter close to that of the anchoring means of the tubular insert. Thus, the protective ring ensures by its external surface a guiding of the device inside the first section of the bore of the rigid element for better centering of the whole of the device in the bore and in particular of the seal relative to the second section of the bore.

 According to another advantageous characteristic of the invention, the nose has an axial length at least equal to that of the protective ring. Thus, the nose pushes the seal entirely outside of the protective ring so that this seal is housed in its entirety inside the second section of the bore of the rigid element. Advantageously then, the axial length of the nose is limited to a value slightly greater than the axial length of the protective ring. Thus, there is no risk of the nose crushing the seal between its end face and the shoulder formed by a third section of the bore intended to receive the end of the tube.

 According to another advantageous embodiment, in which the device comprises a tubular pusher slidably mounted inside the tubular insert for controlling the unlocking of the retaining means, the pusher has one end projecting from the end of the tubular insert opposite the nose and having a shoulder which, for an unlocking position of the pusher, bears against the end of the tubular insert.

 In an alternative embodiment of the protective ring, the latter has internally a groove forming a housing for the seal.

Other characteristics and advantages of the invention will appear on reading the following description of a particular and non-limiting embodiment in conjunction with the figures in the appendices, among which
- Figure 1 is a sectional view through an axial plane of a quick coupling device according to the invention, shown before mounting inside a rigid element suitably bored in stages
- Figures 2 and 3 are views similar to Figure 1, illustrating the mounting of the device according to the invention inside the bore of the rigid element
- Figure 4 is a view similar to Figures 2 and 3 after assembly
- Figure 5 is a view similar to Figure 4, illustrating the connection of a tube to the rigid element by means of the device according to the invention
- Figures 6 and 7 are partial sectional views through an axial plane, illustrating an alternative embodiment of the protective ring
- Figure 8 is a detail view of the connection zone of the protective ring with the nose, illustrating a first embodiment of the locking means of the ring;
- Figure 9 is a view similar to Figure 6, illustrating a first alternative embodiment of the locking means
- Figure 10 is a view similar to Figures 6 and 7, illustrating a second alternative embodiment of the locking means
- Figures 11 and 12 are views similar to Figures 2 and 3, illustrating an alternative embodiment of the quick coupling device according to the invention.

 With reference to the figures, and in particular to FIG. 1, the device for quick connection of a tube 101 to a rigid element 103 is in the form of a cartridge insertable in a cylindrical housing 105 of the element 103. It comprises a tubular insert 1 intended to be housed in the housing 105 of the element 103.

The insert 1 here has two parts: a tubular body 3 and a joint support 5. The outer face of the part 3 is provided with asperities 7 in the form of fir teeth forming means for anchoring the insert 1 in the housing 105. The two parts 3 and 5 define between them an internal groove 9 which constitutes a housing for a washer 11 provided with hooking and retaining teeth of the tube 101 which will be introduced into the tubular insert 1, like this will be better explained later. The washer 11 which is known in itself, is elastically deformable and substantially frustoconical, its inner circumference being of diameter less than that of the tube 101.

 A tubular pusher 13 is mounted to slide axially inside the part 3 of the insert 1 between an inactive output position in which it abuts by a shoulder 15 against a shoulder 17 of the part 3, the washer 11 being then simply pressing on one end 19 of this pusher 13, and an active retracted position in which the shoulders 15 and 17 are spaced from one another and the end 19 lifts the teeth of the washer 11. In addition, the internal diameter of the pusher 13 is close to that of the tube 101. Such an arrangement is well known in this type of connection.

 According to an essential characteristic of the invention, the part 5 of the insert 1 comprises a nose 21 with an outside diameter smaller than that of the anchoring means 7. A protective ring 23 with an inside diameter close to the outside diameter of the nose 21 is mounted at the free end of the nose 21 and extends axially projecting from this nose to internally receive a seal 25. This seal here has a cylindrical outer surface of diameter slightly larger than the inner diameter of the protective ring 23, and an inner toric surface with an inner diameter slightly smaller than the outside diameter of the tube 101. Furthermore, in the example illustrated, the ring 23 has an outside diameter close to that of the means d anchor 7 of insert 1.

 In Figures 6 and 7, there is shown an alternative embodiment of the protective ring. This ring, referenced 53, internally has a groove 55 forming a housing intended to receive the seal 57 to immobilize it axially. This variant is particularly well suited to the use of an O-ring seal, as is the case in the example illustrated.

 According to another essential characteristic of the invention, the ring 23 is immobilized axially on the nose 27 by a low resistance blocking means. In this case, as can be seen more clearly in FIG. 8, the nose 21 and the ring 23 are produced in a single piece connected by a connection zone 27 which has poor mechanical characteristics. However, it is also possible to produce the means for blocking the ring 23 in other forms. Two examples of alternative embodiments of this locking means have been shown in FIGS. 9 and 10.

 In FIG. 9, a first variant is shown, according to which the ring 23 is locked by means of a bonding zone 41 of this ring with the nose 21. In a second variant, illustrated by FIG. 10, the ring 23 has an inner projection 43 in the form of a fir tooth formed on an end portion 45 of the ring 23 radially elastic. The tooth 43 cooperates with an associated peripheral groove 47 formed in the nose 21. With this locking means, the ring 23 does not risk accidentally disengaging the nose 21 since the tooth 43 opposes any effort to withdraw the ring 23. On the other hand, when the insert 1 is introduced into the bore 105 of the element 103 and the ring 23 comes into abutment against the transverse bearing face 117, the axial thrust force exerted on the insert 1 causes the tooth 47 to slide against the bottom of the groove 47 which forms a ramp causing the end portion 45 of the ring to bend 23. The tooth 43 thus leaves the groove 47 and allows the ring to slide. 23 on the nose 21 as indicated previously.

 In addition to the nose 21, the part 5 comprises a portion 29 whose outside diameter is equal to that of the part 3. This portion 29 forms a shoulder which has a transverse face 31 opposite the ring 23 and which constitutes a stop for this one.

 Before mounting, the rigid element 103 must be suitably bored to form the cylindrical housing 105 intended to receive the insert. This housing is here in the form of a bore divided axially into four sections.

We distinguish from left to right a large diameter section 107 intended to receive the insert 1, a smaller diameter section 109 intended to receive the seal 25, a section 111 whose diameter corresponds substantially to the outside diameter of the tube 101 to be connected. and a section 113 whose diameter is substantially equal to the inside diameter of this tube. Between the sections 111 and 113, a transverse bearing face 115 constitutes a stop for the insertion of the tube 101. In the example illustrated, the section 111 has a slightly conical end whose small base is connected to the face 115, in order to create a slight compression of the terminal end of the tube when it enters the section 111 and when it comes into abutment against the face 115.

Between the sections 105 and 109, a transverse support face 117 constitutes a stop for the depression of the ring 23 in the section 107.

 During mounting, the seal 25 is lubricated beforehand. This delicate operation is facilitated by the accessible arrangement of the seal 25 which is held in the ring 23 before it is mounted. In accordance with FIG. 2, the insert 1 is forcibly inserted into the section 107 of the bore 105 by means of a tool 119 in the form of a sleeve whose internal diameter is close to the external diameter of the tubular plunger 13. At this Indeed, the sleeve 119 covers the part of the pusher 13 which extends projecting relative to the part 3 of the insert and its front bearing face 121 abuts against this part 3. An axial thrust force, symbolized by the arrow F in FIG. 2, is exerted on the sleeve 119 in order to make the insert 1 penetrate inside the section 107 of the bore 105.

 It will be noted in this connection that the ring 23, which has a cylindrical outer face with a diameter close to the inner diameter of the section 107, improves the guiding and the centering of the insert 1 inside the section 107. In particular, when the fitting force is applied to make the teeth 7 penetrate into section 107, the significant length of this guide, denoted L in FIG. 2, makes it possible to avoid any bracing of the insert 1 at the inside section 107.

 When the ring 23 comes into abutment against the transverse bearing face 117, the axial thrust force exerted on the sleeve 119 generates on the connection zone 27 of the ring 23 to the nose 21 a cutting force which is sufficient to break this connecting area. The nose 21 then slides inside the sleeve 23 and pushes the seal 25 in the section 109 of the bore 105, as is symbolized by FIG. 3. It will be noted in this connection that the internal diameter of the ring 23 is substantially equal to or slightly less than the diameter of the section 109. In addition, the ring 23 is guided by its outer face in the section 107 for optimum centering of the inner face of this ring relative to the section 109. The seal 25 does not therefore undergoes no friction against the common edge of the transverse face 117 and of the section 109 during its transfer from the ring 23 to this section 109 and is therefore preserved from any deterioration.

 In the example illustrated, the axial length of the nose 21 is slightly greater than that of the ring 23. Thus, when the ring 23 comes into abutment against the transverse face 31 of the part 5 of the insert 1, the seal 25 is fully disengaged from the ring 23. In addition, the fact that the ring 23 abuts against the face 31 and thus limits the length of the nose 21 makes it possible to avoid crushing of the seal 25 between the end face of the nose 21 and the face 118. The sleeve 119 can then be removed.

 In accordance with FIG. 4, an operating ring 31 is mounted on the end of the tubular pusher 13 which projects in relation to the part 3 of the insert 1, in order to facilitate the subsequent operation of this pusher.

In the example illustrated, the ring 31 has a V-shaped radial section open in the direction of the part 3 and comprises a substantially flexible inner branch 33 fitted on its inner face with a flange 35 to cooperate with a peripheral groove 37 formed in the end of the pusher 13. The operating ring 31 can thus be mounted by hand without tools after the sleeve 119 has been removed.

 During the introduction of the tube 101 inside the insert 1, there is a lifting of the teeth of the washer 11 which thus remain elastically pressed against the outside face of the tube 101 and compression of the seal 25 for a connection rigid and watertight of the tube 101 in the element 103, as illustrated in FIG. 5.

 In Figures 11 and 12, there is shown an alternative embodiment of the quick coupling device according to the invention. The only change compared to the previously described embodiment concerns the pusher 13.

The latter is here provided with an external shoulder 49 formed on its end portion opposite to the washer 11 and projecting from the end of the insert 1 opposite the nose 21. During assembly, use is thus made a suitable tool 121 which is no longer supported on the insert 1, but on the shoulder 49 of the pusher 13 and exerts on it a thrust force
F. After a short sliding of the pusher 13 inside the insert 1 causing the teeth of the washer 11 to rise, the shoulder 49 bears against the corresponding end of the insert 1. The pushing force F exerted by the tool 121 is thus transmitted to the insert 1 without the washer 11 being crushed by the pusher 13.

 It is in fact understood that it is more convenient to exert the mounting force on the pusher 13 than directly on the insert 1 insofar as, in any event, the pusher 13 protrudes outside of insert 1 and is therefore more directly accessible.

 The invention is not limited to the embodiments which have just been described but on the contrary includes any variant incorporating, with equivalent means, the essential characteristics set out above.

Claims (9)

 1. Device for quickly connecting a tube (101) in the form of a cartridge insertable into a cylindrical housing (105), comprising a tubular insert (1) having externally means for its anchoring (7) in the housing (105) and internally retaining means (11) of the tube (101), and a seal (25; 55), characterized in that the tubular insert (1) has a nose (21) with an outside diameter smaller than that anchoring means (7) of the tubular insert (1) and a protective ring (23; 53) of internal diameter close to the external diameter of the nose (21), this ring being mounted on the free end of the nose (21) and being immobilized axially relative to this nose by a locking means (27) of low resistance in an axially projecting position relative to this nose to receive internally the seal (25; 55).  2. Connection device according to claim 1, characterized in that the means for blocking the protective ring (23; 53) consists of a connection zone (27) of this protective ring to the nose (21) which is of poor mechanical characteristics.  3. Connection device according to claim 1, characterized in that the locking means of the protective ring (23) consists of a bonding zone (41) of this ring with the nose (21).  4. Connection device according to claim 1, characterized in that the means for blocking the protective ring (23) has an internal projection (43) formed on the protective ring (23) and cooperating with an associated peripheral groove ( 47) of the nose (21).  5. Connection device according to one of the preceding claims, characterized in that the protective ring (23; 53) has an outside diameter close to that of the anchoring means (7) of the tubular insert (1).  6. Connection device according to one of the preceding claims, characterized in that the nose (21) has an axial length at least equal to that of the protective ring (23; 53).  7. Connection device according to claim 6, characterized in that the axial length of the nose (21) is limited to a value slightly greater than the axial length of the protective ring (23; 53).  8. Connection device according to one of the preceding claims, comprising a tubular plunger (13) slidably mounted inside the tubular insert (1) to control the unlocking of the retaining means (11), characterized in that that the pusher (13) has one end projecting from the end of the tubular insert (1) opposite the nose (21) and comprising a shoulder (49) which, for an unlocking position of the pusher (13 ), bears against the end of the tubular insert (1)  9. Connection device according to one of the preceding claims, characterized in that the protective ring (53) has internally a groove (55) forming a housing for the seal (57).