FR2729736A1 - 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.

 There are known quick connection devices of the "cartridge" type 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 made 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 be a sliding pusher between the tube and the body to lift the teeth and allow the tube to be disconnected.

 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, there is provided a device for quick connection of a tube to a rigid element having a stepped bore, comprising a tubular insert having means for anchoring to the rigid element and means for retaining the tube, and a seal, in which the tubular insert has a nose of smaller outside diameter than the rest of 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 weak resistance blocking means to extend axially projecting relative to this nose and internally receiving 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 push 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 blocking means consists of a zone of connection of the protective ring to the nose which has low mechanical characteristics.

 According to an advantageous characteristic of the invention, the protective ring has an outside diameter close to the outside diameter of the rest 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 an 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.

Other characteristics and advantages of the invention will appear on reading the following description of a particular 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.

 Referring to the figures, and in particular to Figure 1, the device for quickly connecting a tube 101 to a rigid element 103 comprises a tubular insert 1 intended to be housed in a stepped bore 105 of the element 103. L insert 1 here has two parts - a tubular body 3 and a seal support 5. The outer face of part 3 is provided with rough edges 7 in the shape of fir teeth. The two parts 3 and 5 define between them a groove 9 which constitutes a housing for a washer 11 provided with hooking teeth and retaining the tube 101 which will be introduced into the tubular insert 1, as 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 of smaller outside diameter than the rest of the insert. A protective ring 23 with an internal diameter close to the external diameter of the nose 21 is mounted at the free end of the nose 21 and extends axially projecting relative to this nose to internally receive a seal 25. This seal d the seal is here toroidal in shape and has, before mounting, an outside diameter slightly larger than the inside diameter of the protective ring 23 and an inside diameter slightly smaller than the outside diameter of the tube 101.

 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, the nose 21 and the ring 23 are made in a single piece connected by a connecting zone 27 which has low mechanical characteristics.

 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. The bore 105 is axially divided 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 bearing face 117 constitutes a stop when the ring 23 is pushed into 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 should be noted in this connection that the ring 23, which has a cylindrical outer face of 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 penetrate the teeth 7 in section 107, the significant length of this guide, denoted L in FIG. 2, makes it possible to avoid any arching of the insert 1 inside the 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.

 The invention is not limited to the embodiment which has just been described but on the contrary includes any variant incorporating, with equivalent means, the essential characteristics set out above. In particular, although a means for blocking the protective ring on the nose has been described, produced in the form of a connection zone of low mechanical resistance, it is possible to produce this means in any other form. For example, provision could be made to equip the protective ring with a radially elastic inner rim and cooperating with a peripheral groove formed externally on the nose.

Claims (5)

 1. Device for quick connection of a tube (101) to a rigid element (103) having a stepped bore (105), comprising a tubular insert (1) having anchoring means (7) to the rigid element ( 103) and retaining means (11) of the tube (101), and a seal (25), characterized in that the tubular insert (1) has a nose (21) of smaller outside diameter than the rest of the tubular insert (1) and a protective ring (23) with an 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 with respect to to this nose by a blocking means (27) of low resistance to extend axially projecting with respect to this nose and to receive internally the seal (25).  2. Connection device according to claim 1, characterized in that the locking means consists of a connection zone (27) of the protective ring (23) to the nose (21) which is of low mechanical characteristics.  3. Connection device according to one of the preceding claims, characterized in that the protective ring (23) has an outside diameter close to the outside diameter of the rest of the tubular insert (1).  4. 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).  5. Connection device according to claim 4, 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).