WO1999008037A1

WO1999008037A1 - Device for quick connection of a tube to a rigid element

Info

Publication number: WO1999008037A1
Application number: PCT/FR1998/001678
Authority: WO
Inventors: Philippe Blivet
Original assignee: Legris S.A.
Priority date: 1997-08-07
Filing date: 1998-07-29
Publication date: 1999-02-18
Also published as: AR015143A1; FR2767181B1; AU8984098A; FR2767181A1

Abstract

The invention concerns a device for the quick connection of a tube (40) to a rigid element (30), comprising a tubular insert (1) having externally means (2) for being fixed into a bore (34) of the rigid element and internally means for axially blocking the tube relative to the insert (1) countering at least the extraction of the tube. The axial blocking means comprise: a shoulder (10) arranged in the tubular insert (1), facing the rigid element (30); a groove arranged in the tube and having a support flank (42) facing the opposite direction at the tube end; a tubular sleeve (12) set between the tube (40) and the tubular insert (1) inner surface, whereof at least an axial section designed to penetrate into the tube (40) groove is capable of elastic radial deformation as the tube end passes through when it is introduced in the insert (1) and constitutes a shape-retaining obstacle preventing the flank (42) and the shoulder (10) from coming together axially in the presence of a force urging the tube (40) and the insert (1) axially apart.

Description

Device for quick connection of a tube to a rigid element.

The present invention relates to a device for quick connection of a tube to a rigid element.

There are known quick connection devices of the "cartridge" type intended to make the sealed connection of a tube in a bore of a rigid element such as a body of a hydraulic or pneumatic component. In general, this type of connector comprises a tubular insert having externally means for fixing it in a housing of the rigid element and internally means for locking the tube in the insert, a seal being arranged between the tube and the housing of the rigid element.

In the most common quick connect devices, the insert is screwed into a thread in the bore of the rigid element and the locking of the tube is ensured by a deformable anchoring washer having radial prongs which come to "bite". the outer face of the tube.

The axial immobilization of the tube in the insert is generally not rigidly ensured in this type of connection for the following reasons. First there may be a functional clearance between the claw washer and the insert itself. In addition and above all, the claws are flexible strips which, in the event of traction on the tube, work in elastic buckling so that the more the traction effect is high the more the deformations of the teeth are important and the more the axial displacement of the tube compared to the insert is important.

In reality the tensile force on the tube is generated by the pressure prevailing in the circuit to which the tube belongs. Some circuits are permanently under constant pressure. The tube takes its place in the insert and in this case the claw fittings are quite sufficient. In other circuits the pressure is variable over a large range of amplitudes and sometimes at a high frequency. This is particularly the case for motor vehicle braking systems fitted with anti-lock braking systems.

In these latter conditions of use, the claw couplings have drawbacks: each claw is subjected to a fatigue strain in buckling which shortens the life of the ring.

The internal volume of the circuit is not constant because the tube moves relative to the insert under the effect of pressure variations, which can cause disturbances in the operation of certain devices served by the circuit and in particular of the devices anti-lock brakes.

In fact, in these applications to braking circuits, the operating pressures can vary between 100 bars and 350 bars at peak, with pulses of 15 hertz.

An object of the invention is to design a quick connection device in which the locking of the tube has a high axial rigidity against the forces of withdrawal of the tube with a clearance, if not zero, at least fixed and predetermined in the direction of withdrawal.

In order to achieve this goal, there is provided according to the invention a device for quick connection of a tube to a rigid element, comprising a tubular insert having externally means for fixing it in a bore of the rigid element and internally means for axially immobilizing the tube with respect to the insert opposing at least the extraction of the tube, in which the means for axially immobilizing comprise: - a shoulder formed in the interior surface of the tubular insert, turned towards the rigid element,

- a groove formed in the outer surface of the tube and having a support flank facing in the opposite direction to the end of the tube, - a tubular sleeve interposed between the tube and the inner surface of the tubular insert (1) of which at least one axial section intended to penetrate into the groove of the tube is elastically deformable radially when the end of the tube passes through when it is introduced in the insert and constitutes a non-deformable obstacle opposing the axial bringing together of the sidewall and the shoulder during a tandant effort to axially separate the tube from the insert.

In service, the sleeve is thus interposed between the shoulder of the insert and the side of the groove of the tube to form a positive stop for rigid retention of the tube in the insert. During assembly, the insertion of the tube into the insert takes place thanks to the radial elastic expansion of the deformable section of the sleeve. As soon as the side of the groove of the tube has crossed the deformable section of the sleeve, the latter retracts into the groove to oppose the withdrawal of the tube. The withdrawal forces exerted axially on the tube are taken up, between the side of the groove of the tube and the internal shoulder of the insert, by the sleeve which is non-deformable.

In a first embodiment, the shoulder of the insert and the support flank of the groove of the tube are straight and radial and the axial section of the elastically deformable sleeve has a wide end arranged to come into abutment against the shoulder radial of the tubular insert, and a narrow end arranged to elastically penetrate the groove of the tube and come to bear against the radial side of this groove.

In a second embodiment, the shoulder of the insert has at least one frustoconical part diverging towards the rigid element, the bearing flank of the groove of the tube is frustoconical, and the section with elastic radial deformation of the sleeve has one end, the inner surface of which bears on the frustoconical flank of the groove of the tube and the outer surface is supported on one frustoconical shoulder of the insert when the support flank of the tube is brought axially closer to the shoulder of the insert.

According to an advantageous embodiment of the sleeve, the latter has a continuously converging interior passage from a wide end to a narrow end. The wide end of the sleeve has a cross section of polygonal shape, while the narrow end of this sleeve has a cross section composed of a succession of arcs of circle whose intersections are connected to the vertices of the polygonal section of the wide end by longitudinal edges between which the sleeve has curved external facets. A sleeve is thus obtained having an intrinsic capacity for radial elastic deformation and having a reduced radial size, as well as good resistance to compression. The longitudinal edges also reinforce the compressive strength of the sleeve by opposing its buckling. Advantageously, the sleeve is made of stamped steel. The sleeve thus has optimum elasticity and mechanical strength characteristics, while being particularly simple and inexpensive to manufacture. There is also provided, according to the invention, a cartridge for conditioning the insert and the sleeve used in the connection device, in which the tubular insert provided internally with the sleeve is equipped with an internal retaining sleeve having a portion fitted into the tubular insert, a guard forming a closure plug at one end of the tubular insert and at least two elastically flexible branches having a free end extending beyond the other end of the insert and fitted with radial projections for retaining the sleeve in the insert. Advantageously, the cartridge comprises, between the projecting end of the legs of the sheath and the insert, a washer whose internal diameter is less than the internal diameter of the insert at the corresponding end and whose external diameter is at most equal to outside diameter of the insert at this end. The washer has at least three elastic tabs that can be folded down along the insert outside of it.

The free end of the elastic branches of the sheath is equipped beyond the insert and the washer with an annular seal, the radial projections of these branches constituting means of axial retention of the sleeve, washer, and seal. compared to the insert. The free end of the branches of the sheath has an external chamfer arranged to force the bending of the branches of the sheath towards one another when their end penetrates into an associated portion of the bore of the rigid element.

Other characteristics and advantages of the invention will appear on reading the following description of particular embodiments, given by way of nonlimiting examples.

Reference will be made to the accompanying drawings, among which: - Figure 1 is an axial sectional view of a cartridge of a connection device according to one invention;

- Figure 2 is a detailed perspective view of the sleeve alone; - Figure 3 is a detail view in axial section of the sleeve of Figure 2;

- Figures 4 and 5 are views respectively according to arrows IV and V of Figure 3;

- Figures 6 and 7 are views in axial section illustrating the mounting of the cartridge of the device connection in an associated housing of the rigid element to which the tube is to be connected;

- Figures 8 and 9 are views in axial section illustrating the introduction and axial locking of the tube in the insert;

FIG. 12 is an enlarged view of the boxed area A of FIG. 9.

- Figures 10 and 11 are views similar to Figures 8 and 9 respectively, illustrating an alternative embodiment of a connection device according to one invention;

FIG. 13 is an enlarged view of the boxed area B of FIG. 11.

Referring to Figures 1 to 9 and in particular to Figure 1, the device for quickly connecting a tube to a rigid element according to the invention comprises a tubular insert 1 having an external thread 2 for fixing, a front transverse face 3 and a rear transverse face 4. The tubular insert 1 internally has a bore with an axis shaft 5. This bore has successively, from the rear face 4 to the front face 3, an inlet chamfer 7, a first cylindrical portion 8 and a second cylindrical portion 9 of larger diameter than the first portion 8. An interior transverse shoulder 10 separates the first and second portions 8 and 9.

A locking sleeve 12 is arranged in the second cylindrical portion 9 of the stage bore of the insert 1. As is better visible in FIGS. 2 to 5, this locking sleeve has a narrow front end 13 and a wide rear end 14. The narrow front end 13 has a cross section composed of a succession of re-entrant arcs of a circle. The arcs of circle form between them intersections which are here relatively angular, but could advantageously be more rounded to facilitate the manufacture of the sleeve 12. The wide rear end 14 has a polygonal cross section. Longitudinal stiffening edges 15, substantially parallel to one another, connect the vertices of the polygonal section of the wide rear end 14 to the intersections of the circular arcs of the section of the narrow front end 13. Between the edges 15, the sleeve 12 has external curved and concave side facets 16. In this case, the edges 15 are six in number, the section of the wide rear end

14 being hexagonal. The detailed definition of the shape of the locking sleeve 12 is further defined by Figures 2 to 5 which are given for description.

The locking sleeve 12 can advantageously be made of pressed steel. Its manufacture is thus simple and rapid, and therefore inexpensive. The use of steel makes it possible to combine satisfactory characteristics of elasticity and mechanical resistance to compression, this material also being inexpensive and well suited to production by stamping. The thickness of the locking sleeve depends on the dimensions of the fitting and the degree of stress to which it is subjected. For connection devices used in the automotive field, a thickness of between 0.2 and 0.4 mm is optimal. Similarly, the number of edges

15 of the sleeve may be variable but will preferably be between 3 and 12.

The locking sleeve 12 thus has a

-internal passage 17 of axis 5 which is continuously converging from the wide rear end 14 to the narrow front end 13 of the sleeve 12. The shape in succession of arcs of circle of the narrow front end 13 and the curved shape lateral facets 16 provide the locking sleeve 12, and in particular at its narrow front end 13, with an elastic deformation capacity according to a radial direction. In other words, the narrow front end 13 of the sleeve 12 is elastically expandable.

The locking sleeve 12 has a length close to that of the second cylindrical portion 9 of the bore of the tubular insert 1. Its wide rear end 14 abuts against the internal shoulder 10 of the insert 1. Its end narrow front 13 abuts against a washer 18 disposed against the front face 3. This washer 18 has external tabs 18.1 folded forward by an angle less than the right angle and elastically flexible.

The connection device also comprises an annular seal 19 intended to seal between the tube and the rigid element to which it must be connected, as will be better explained later.

Before mounting the device on the rigid element which is the subject of the connection, the seal 19 is held in position, pressing against the washer 18 by an inner retaining sleeve 20. The assembly consisting of the insert 1, the sleeve 12, seal 19 and sleeve thus form a pre-assembled cartridge ready for use.

The sheath 20 comprises a fixing portion 21 fitted into the first cylindrical portion 8 of the bore of the tubular insert 1, and two elastically deformable branches 22 separated by slots 23.

The deformable branches 22 have a free front end 24 which projects from the front face 3 of the tubular insert 1 and which has a seat 25 delimited at the front by a projection in the form of a conical shoulder 26 constituting a stop for the seal 19. The free front end 24 of the branches 22 also has an external chamfer 24.1.

Behind the fixing portion 21, the sheath is provided with a handle 27 and a guard obturation- and positioning 28 which abuts against the rear face 4 of the insert 1. The guard 28 thus obstructs the bore of the tubular insert 1, which prevents the penetration of impurities during the operations of transport, storage and assembly. On the other hand, the distance between the guard 28 and the conical shoulder 26 delimiting the seat of the seal 19 is chosen so that the shoulder 26 ensures a maintenance with little play of the seal 19, the washer 18 and the locking sleeve. 12 against the internal shoulder 10 of the turbular insert 1.

The connection device is mounted on a rigid element 30 as follows, in accordance with the illustrations in FIGS. 6 to 9.

The rigid element 30 must first be bored to form a stepped bore. This bore is divided into four portions of diameters narrowing from the outside to the inside. There is thus a large diameter portion 31 tapped and intended to receive the insert 1, a portion 32 of smaller diameter than the portion 31 and intended to receive the legs 18.1 of the washer 18, a portion 33 of smaller diameter than the portion 32 and intended to receive the joint 19, a portion 34 whose diameter corresponds substantially to the outside diameter of the tube to be connected and a portion 35 whose diameter is substantially equal to the inside diameter of this tube.

During assembly, the insert 1 is screwed by its external thread 2 into the thread of the first portion 32 of the stage bore of the rigid element 30. The seal 19 is compressed externally to penetrate into the second portion 33 of the bore and on each of its sides between the washer 18 and a shoulder 37 separating the second and third portions 33 and 34 of the bore of the rigid element 30. Simultaneously, the elastic tabs 18.1 of the washer 18 penetrate into the portion 32 of the bore of the insert 1 and, by friction, immobilize in rotation of the washer 18, which prevents it from being rotated by the insert 1 and does not affect the seal 18 by friction. The free ends 24 of the branches 22 of the retaining sleeve 20 penetrate into the third portion 34 of the bore of the rigid element 30 and their external chamfer 24.1 forces the branches 22 of the sheath 20 to bend slightly towards each other by elastic deformation, which frees the sheath and prevents friction of the sheath on the joint at the end of the screwing of the insert 1. At the end of the screwing, the washer 18 abuts against a shoulder 36 separating the first and second portions 32 and 33 of the stage bore of the rigid element 30.

As illustrated in FIG. 7, a tensile force is exerted on the sheath 20 via the handle 27 to remove the retaining sheath 20 from the turbular insert 1. The fixing portion 21 slides at the inside the first cylindrical portion 8. The end 24 of the arms 22 of the sleeve 20, which slides first on the joint 19 and then on the narrow front end 13 of the locking sleeve 12, forces the elastic bending of the arms 22 l 'towards each other, to allow the withdrawal of the sheath 20 without forcing the elasticity of the seal 19 and the sleeve 12. The sheath 20 being removed, the tube 40, which must be connected to the rigid element 30, is introduced into the tubular insert 1 in accordance with FIG. 8. This tube has an outside diameter close to the diameter of the first cylindrical portion 8 of the bore of the tubular insert 1 and has on the outside a groove 41 which defines a shoulder 42. In the es piece, the groove 41 is of conical shape converging towards the free front end face 43 of the tube 40.

The front end 44 of the tube 40, which is rounded or chamfered, enters the converging interior passage. giant 17 of the locking sleeve 12 and, sliding on the inner surface of the sleeve 12, forces the elastic expansion of the front end 44 of the sleeve 12 to allow the passage of the front end of the tube 40. When the shoulder 42 crosses the narrow front end 13 of the sleeve 12, the latter retracts spontaneously in the groove 41 under the effect of its own elasticity and thus locks the tube 40 in the tubular insert 1.

As illustrated by FIGS. 9 and 9a, any extraction force exerted on the tube 40, in particular due to the increase in pressure inside the tube 40, is taken up, via the shoulder 42, by the locking sleeve 12 which is itself immobilized axially in abutment against the internal shoulder 10 of the turbular insert 1. The sleeve 12 is thus subjected to significant compressive stresses which it safely collects thanks to its particular shape previously described and illustrated in Figures 2 to 5. In particular the longitudinal stiffening edges 15 substantially strengthen the resistance of the sleeve 12 in particular avoiding any risk of buckling.

Beyond the shoulder 42, the front end 44 of the tube 40 is in contact with the seal 19 and compresses it slightly, so that the seal between the tube 40 and the rigid element 30 is ensured .

Figures 10, 11 and 11a illustrate an alternative embodiment of the invention in which the locking sleeve 12 has been mounted in the opposite direction to that of the embodiment previously described with reference to Figures 1 to 9. The narrow end 13 is therefore here facing the rear face 4 of the insert 1, that is to say opposite the rigid element 30, and the wide end 14 is facing the front face 3 of the insert 1, that is to say towards the rigid element 30. The insert 1 has, between the portions 8 and 9 of its bore, a shoulder having a frustoconical part 50 facing the front face 3 of the insert 1 and a straight radial part 51.

The distance between the straight part 51 of the washer 18 is slightly greater than the length of the sleeve 12, so that the latter is mounted with a small axial clearance in the insert. Similarly, the diameter of the part 9 of the bore of the insert 1 is slightly greater than the outside diameter of the sleeve 12 which is consequently mounted with a radial clearance.

The tube to be connected, designated by the reference 52, has a groove having a frustoconical support flank 53 turned towards the rear, that is to say diverging towards the end 55 of the tube 52, and a straight radial flank 54 facing forward.

During assembly, the front end 55 of the tube 52, which is chamfered, bears against the narrow end 13 of the sleeve 12 and forces it to open out elastically to allow its passage. The narrow end 13 of the sleeve 12 then retracts under the effect of its own elasticity against the frustoconical flank 53 of the groove of the tube until the narrow end abuts against the right flank 54 of the groove of the tube.

An axial withdrawal force subsequently exerted on the tube 52 causes a displacement of the tube 52 and of the sleeve 72, the narrow end 13 of which abuts against the straight part 51 of the shoulder of the insert.

The withdrawal force exerted on the tube 52 then tends, due to the conicity of the support flank 53 of the groove of the tube, to widen the narrow end 13 of the sleeve 12. But this end is circumscribed by the narrow base of the conical part 50 of the shoulder of the insert 1, the diameter of which is equal to its outside diameter and which therefore prevents its development and, consequently, the axial withdrawal of the tube 52. The invention is not limited to the embodiments which have just been written, but on the contrary encompasses any variant incorporating, with equivalent means, its essential characteristics. In particular, although a locking sleeve having concave external lateral facets has been described, it will also be possible to produce a locking sleeve having convex external facets, the narrow end of this sleeve then having a cross section hexagonal and the wide end having a circular section or composed of a succession of outgoing circular arcs. In general, it will moreover be possible to produce a locking sleeve having any shape having a wide end and a narrow end and having a capacity for elastic expansion of its narrow end.

Claims

1. Device for quick connection of a tube (40; 52) to a rigid element (30), comprising a tubular insert (1) having externally means (2) for fixing it in a bore (34) of the element rigid (30) and internally means for axially immobilizing the tube (40; 52) relative to the insert (1) opposing at least the extraction of the tube, characterized in that the means for axially immobilizing comprise: a shoulder (10; 50, -51) formed in the interior surface of the tubular insert (1), turned in the direction of the rigid element (30),

- a groove formed in the outer surface of the tube and having a support flank (42, -53) turned in the opposite direction to the end of the tube,

- a tubular sleeve (12) interposed between the tube (40; 52) and the inner surface of the tubular insert (1), at least one axial section of which is intended to penetrate into the groove of the tube (40, -52) is elastically deformable radially when the end of the tube passes when it is inserted into the insert (1) and constitutes a non-deformable obstacle opposing the axial approach of the sidewall

(42; 53) and the shoulder (10; 50; 51) during a tê.nd effort to axially separate the tube (40; 52) from the insert

(1) •

2. Device according to claim 1 characterized in that the shoulder (10) of the insert (1) and the

-bearing side (42) of the groove of the tube (40) are straight and radial and in that the axial section of the elastically deformable sleeve (12) has a wide end (14) arranged to come into abutment against the shoulder radial (10) of the tubular insert (1), and a narrow end (13) arranged to elastically penetrate the groove of the tube (40) and come to bear against the radial side (42) of this throat.

3. Device according to claim 1, characterized in that the shoulder of the insert (1) has at least one frustoconical part (50) diverging towards the rigid element (30), in that the bearing flank ( 53) of the groove of the tube (52) is frustoconical, and in that the section with elastic radial deformation of the sleeve (12) has one end whose inner surface bears on the frustoconical flank (53) of the groove of the tube and the outer surface bears on the frustoconical shoulder (50) of the insert (1) when the support flank (53) of the tube is axially brought closer to the shoulder (50; 51) of the insert .

4. Device according to one of claims 2 and 3 characterized in that the sleeve (12) has an interior passage (17) continuously converging from a wide end (14) to a narrow end (13).

5. Device according to claim 4, characterized in that the wide end (14) of the sleeve (12) has a cross section of polygonal shape, while the narrow end (13) of this sleeve has a cross section composed of '' a succession of arcs of a circle whose intersections are connected to the vertices of the polygonal section of the wide end (14) by substantially longitudinal edges (15) between which the sleeve (12) has curved external facets (16) .

6. Device according to claim 5, characterized in that the external facets (16) of the sleeve (12) are concave.

7. Device according to claim 6, characterized in that the longitudinal stiffening edges (15) of the sleeve (12) are substantially parallel to one another.

8. Device according to one of claims 5 to 7, characterized in that the sleeve (12) is made in stamped steel and has a thickness between 0.2 and 0.4 millimeter.

9. Device according to one of claims 5 to 8, characterized in that the sleeve (12) has a number of edges (15) between 3 and 12.

10. Cartridge for conditioning the insert and the sleeve used in the connection device according to one of the preceding claims, characterized in that the tubular insert (1) provided internally with the sleeve (12) is equipped with an inner retaining sleeve (20) having a portion (21) fitted into the tubular insert (1), a guard (28) forming a plug for closing one end of the tubular insert (1) and at least two elastically flexible branches (21) having a free end (24) extending beyond the other end of the insert and equipped with radial projections for retaining the sleeve in the insert.

11. Cartridge according to claim 10, characterized in that it comprises, between the projecting end of the branches (21) of the sheath (20) and the insert (1), a washer (18) whose inner diameter is smaller to the inside diameter of the insert (1) at the corresponding end and whose outside diameter is at most equal to the outside diameter of the insert (1) at this end.

12. Cartridge according to claim 11, characterized in that the washer (12) comprises at least three elastic tabs (18.1) which can be folded down along the insert (1) outside of the latter.

13. Cartridge according to one of claims 11 and 12, characterized in that the free end of the elastic branches (21) of the sleeve (20) is fitted beyond the insert and the washer with a seal d annular seal (19), the radial projections of these branches constituting the axial retaining means of the sleeve (12), washer (18), and seal (19) relative to the insert (1). 14: Cartridge according to one of claims 10 to 13, characterized in that the free end (24) of the branches (21) of the sleeve (20) has an outer chamfer (24.1) arranged to force the bending of the branches (21 ) of the sleeve (20) towards each other when their end (24) penetrates into an associated portion (34) of the bore of the rigid element (30).