WO1993016317A1

WO1993016317A1 - Method and device for securing a hose to a rigid end fitting

Info

Publication number: WO1993016317A1
Application number: PCT/FR1993/000109
Authority: WO
Inventors: Daniel Baron
Original assignee: Manuli Automobile France S.A.
Priority date: 1992-02-05
Filing date: 1993-02-02
Publication date: 1993-08-19
Also published as: EP0626051A1; FR2686961A1; FR2686961B1

Abstract

A device (1) is disclosed for permanently attaching a hose (2) with rigid or semi-rigid (3) core to a rigid end of fitting (4) having substantially the same outside diameter as the inside diameter of the hose. Said device comprises an outer crimping bush (5), one end (6) of which is rigidly attached to rigid end fitting (4), the other end (7) accommodating the end (8) of the hose passed over the end fitting. The ring is crimped by mechanical compression of the said end. The device also comprises a thin, flexible elastomer sleeve (18) having substantially the same outside diameter as the inside diameter of the hose. Said sleeve is placed between the rigid end fitting (4) and the hose core (3).

Description

DEVICE AND METHOD FOR FIXING A FLEXIBLE PIPE ON A RIGID TIP

The present invention relates to a non-removable fixing device for a flexible pipe with a rigid or semi-rigid core on a rigid end piece with an external diameter substantially equal to the internal diameter of the pipe, the device being of the type comprising an external crimping ring, one side of which is secured to the rigid end piece and the other side is arranged to coat the end of the pipe, threaded onto the end piece, on which the ring is crimped by mechanical compression.

It also relates to a method of fixing a flexible pipe to a rigid end piece using such a device.

The invention finds a particularly important, although not exclusive, application in the field of air conditioning circuit tight fittings, for example for a motor vehicle.

One problem posed by pipe fittings on this type of circuit is that of leak tightness.

To minimize leaks, several devices have been proposed to date. They all have drawbacks.

For example, there is known (FR-A-2.615.266) a device for connecting a flexible conduit to a rigid end piece for the cooling fluid of a motor vehicle comprising a heat-shrinkable sheath. The sheath seals in compressing the tube on the end piece by shrinking the sheath.

Such a device requires heating the connector to obtain the shrinkage of the sheath and moreover has a low resistance to the longitudinal pulls exerted on the parts of the connector.

There is also known a device for quick connection of a pipe to end piece (FR-A-2,605,705) comprising an intermediate lining which can be threaded on the end piece, between the tube and the end piece, and capable of greatly or very greatly increasing in volume when 'it is brought into contact with water or moisture.

The significant increase in volume makes it possible to simultaneously maintain the tube on the end piece and seal the device.

Such a solution requires on the one hand the humidification of the connector and on the other hand the installation of a complicated ring including in particular means of radial stop between gasket and pipe to allow the compression of the latter on the nozzle. .

A device of the type defined above is also known (EP 0 447 622). However, such a device does not always ensure sufficient sealing with a pipe whose internal wall is made of rigid or semi-rigid material, taking into account the applicable European or American specifications used in the field of motor vehicle construction.

The present invention aims to provide a device and a method for irremovable fixing of a flexible pipe to a rigid end fitting better than those previously known to the requirements of practice, in particular in that it allows good tightness of connection between rigid or semi-rigid core pipe and rigid end piece, and in that it allows easy mounting without the need to heat or humidify the connection while allowing excellent sealing to be obtained, all for a acceptable cost.

To this end, the invention proposes in particular a device for the irremovable fixing of a flexible pipe with a rigid or semi-rigid core to a rigid end piece with an external diameter substantially equal to the internal diameter of the pipe, the device being of the type mentioned above, characterized in that the device comprises a sleeve having a flexible tubular part made of elastomeric material of small thickness and of external diameter substantially equal to the internal diameter of the pipe, the tubular part of the sleeve being situated between the rigid end piece and the rigid core or semi-rigid pipe.

In advantageous embodiments, one and / or the other of the following arrangements are also used:

- The tubular part of the sleeve is adapted to be inserted easily in said pipe, for example by cooperating effortlessly, and without any lateral pressure being exerted between the internal walls of the pipe and external of the sleeve, before crimping. This can in particular be a relationship of the soft friction type between the walls of the tubular part of the sleeve and of the pipe;

- The sleeve is provided with a sleeve end stop flange on the one hand on the end face of the pipe and on the other hand on the bottom of the ring, on the side integral with the rigid end piece; - The length of the sleeve is between about 5 mm and about 40 mm;

- The sleeve is of length substantially equal to or slightly less than the length of the nozzle. By slightly lower is meant, for example, a few millimeters lower, for example 3 mm. Such an arrangement is particularly advantageous in the case of a large pipe diameter;

- The sleeve is made of elastomeric material based on polymer containing butyl chains;

- The thickness of the tubular or cylindrical part of the sleeve is between approximately 0.1 mm and approximately 1 mm, and advantageously approximately 0.3 to 0.5 mm;

- The ring consists of a stamped sheet metal socket fixed to the end of the tube by frizzing said tube at its end, to block one side of the sleeve in the fold of the tube obtained by frippage;

- The end of the tube comprises between two and six external circular grooves of shallow depression at the sleeve, and advantageously three circular grooves; the device comprises means for visual indication of the presence of the sleeve in the pipe after crimping;

- The visual indication means comprise a tongue integral with the collar extending outward substantially in the plane of the underside of said collar.

The invention also relates to a method of fixing a rigid end piece to a flexible pipe with a rigid or semi-rigid core using the device described above.

The invention will be better understood on reading the following description of particular modes of embodiment given by way of nonlimiting example. The description refers to the accompanying drawings in which:

- Figure 1 is a sectional view of an embodiment of a device according to the invention;

- Figure 2 is a schematic perspective view, partly broken away and in section, of the components of the device of Figure 1, before assembly;

- Figure 3 is a bottom view of a variant of a sleeve for a device according to the invention;

- Figure 4 is a sectional view along IV.IV of Figure 3.

In the following text, the same reference numbers are used to designate the same elements with reference to FIGS. 1 and 2.

FIG. 1 shows a device 1 for the non-removable fixing of a flexible pipe 2 with a semi-rigid tubular core 3 on an end piece 4 of rigid tube 4 •, of substantially equal external diameter (for example equal or less in the order of one tenth of a millimeter) to the internal diameter of the pipe, ie 1 • semi-rigid tubular core 3.

The device 1 comprises an external crimping ring 5, one side 6 of which is secured to the rigid end piece 4 and the other side 7 coats the end 8 of the pipe 2 threaded onto the end piece 4.

More specifically, the ring 5 is constituted by a stamped sheet metal socket fixed to the end piece 4 of the tube by frizzing at 9 of the tube at its end, to block the side 6 of the sleeve in the fold 10 of the tube obtained by frippage.

The material of the ring is for example identical to the material of the end piece, and can be an alloy aluminum or drawn steel such as TU 37 B steel (standards NFA 49310, NFA 49330).

The pipe 2 with semi-rigid core 3 is for example a pipe manufactured by the Italian company MANULI RUBBER INDUSTRIES, Centro Direzionale Milano 2, Pallazo Verrochio, 20090 Segrate (Milan), Italy under the references 1TN, 1TNS, SPW or SPFK.

It includes a core 3 of semi-rigid waterproof nylon. The nylon core is coated by two polyester braids 11, for reinforcement, and a cover or dress in chloroprene elastomer 12. The different elements of the pipe 2 are linked together by known adhesive products.

In the embodiment more particularly described here, the end 8 of the pipe 2 has been thinned, by grinding, so as to allow its introduction into the annular tubular space 14 (see FIG. 2), and cover the end piece 4 of the 4 'tube.

For example, in Figure 1, there is shown the tube 4 'provided on the side of its other end, opposite the end piece 4, connection means 15 known in themselves, for example constituted by a nut 16 for connection with a rigid tube 17 belonging to the circuit for circulating a cooling or heating fluid of a motor vehicle.

According to the invention, the fixing device comprises a flexible tubular cylindrical sleeve 18 made of elastomeric material, of small thickness, for example 0.3 mm thick in its tubular part.

The external diameter of the sleeve is substantially equal to the internal diameter of 1 • rigid or semi-rigid core 3, for example equal to or less than about one tenth of a millimeter to the internal diameter of the core 3. The length of the tubular or cylindrical part of the flexible sleeve is for example substantially equal to the length of the ring 5 or of the end piece 4.

In the embodiment of the invention more particularly described here, the sleeve is provided with an end flange 19, with the sleeve abutment on one side on the end face 20 of the pipe and on the other side on the bottom 21 of the ring secured to the rigid end piece, the sleeve 18 being inserted between the rigid end piece 4 and the core 3 of the pipe.

In the embodiment of the invention applied to vehicle air conditioning circuits, the external diameter of the pipe 2 is for example between 10 mm and 50 mm, the corresponding internal diameter being between 8 mm and 28 mm.

The length of the sleeve is itself, for example, between 5 mm and 40 mm, depending on the diameter of the tube.

The ring 5 is crimped on the end 8 of the pipe 2 by crimping means known in themselves, by exerting a crimping pressure determined for example in three circular locations regularly distributed. The pressure depends on the diameter and the exact constitution of the connected pipe, as well as the material used for the ring. It can be easily determined in a manner known in itself by a person skilled in the art.

In the embodiment more particularly described here, the end piece 4 further comprises four circular grooves made on the external surface of the end piece 22 located in the middle part 23 of the end piece, said grooves or grooves being for example 0.5 mm wide and 0.1 mm deep. They allow better adhesion of the sleeve 18 on the end 4.

The material used for the sleeve is for example a compound based on chlorobutyl, for example the product manufactured by the French company TABUR under the reference CCIR 5710751, the gas or coolant conveyed by the pipe being in this case tetrafluoroethane HFC 134 Used in the air conditioning of passenger vehicles in Europe and the USA and having the advantage of preserving the earth's ozone layer.

We will now describe the waterproof fixing method using the device described above, with particular reference to FIG. 2.

The sleeve 18 is introduced into the end 8 of the pipe 2, for example manually. The substantially equal diameter of the sleeve, for example slightly less than that of the internal core 3 of the pipe 2, as well as the flexibility of said sleeve allow easy introduction of the tubular part of the sleeve until the flange 19 comes into abutment on the end face 20 of the pipe, for example allowing a soft friction connection between the internal wall of the pipe and the external wall of the tubular part of the sleeve.

The rigid end piece 4 of the tube 4 ′ is then forcefully pressed into the pipe 12 thus sheathed by the sleeve 18, until the collar 19 comes into abutment on the bottom 21 of the ring 5, as previously described. This insertion is done for example after widening the pipe by preheating or using a mandrel. The ring 5 is then crimped onto the end 8 of the pipe 2 by mechanical compression.

Such a method of attachment ensures excellent tightness of the pipe and fittings assembly, while allowing the use of a pipe whose permeability rate to the fluid conveyed, in particular in the case of HFC 134 A, is from four to five. times less than a pipe comprising for example a non-rigid elastomer core.

Figures 3 and 4 show another embodiment of the sleeve 22 according to the invention. The sleeve has a tubular part 23 adapted to cooperate with the internal wall of the pipe, similar to that described above with reference to the sleeve 18 and a circular flange 24, of thin thickness, which is extended laterally by a tab 25 made of elastomer. The tongue is for example essentially rectangular and of thinner thickness (for example 0.3 mm). It extends towards the outside over a length of a few centimeters, for example from 3 to 4 cm, ending in an enlarged part 26, for example circular, 6 mm thick. This tab makes it possible to signal the effective presence of the sleeve in the connector once formed and can advantageously and at least in part, be of a bright color, for example red. The tongue is located in the extension of the lower surface 27 of the collar.

As is obvious and as it follows moreover from the foregoing, the invention is not limited to the embodiment more particularly described.

On the contrary, it concerns all variants and in particular those where: - The end flange 19 is provided with one or more small notches, for example V-shaped, regularly distributed (for example four notches) on the periphery of the flange;

- the rigid or semi-rigid core pipe is made differently; the hose is used without rectifying its end;

- Another fluid than that more particularly taken as an example is conveyed by the pipe and its fittings, for example freon;

other means of visual signaling of the presence of the sleeve are provided;

- The sleeve is made of elastomeric material known under the name HNBR (Anglo-Saxon initials of Hydrogened Nitrile Butadiene Rubber). Such a material has especially 1'avantage allow indifferently use as cooling fluid CFC12 = CCI ₂ F ₂ (Dichlorodifluoromethane) or ^"HFC134a;

- The side of the outer ring secured to the rigid end piece is not made integral with said end piece by frippage but by any other suitable method of attachment.

Claims

1. Device (1) for non-removable fixing of a flexible (2) rigid or semi-rigid core pipe (3) on a rigid end piece (4) with an external diameter substantially equal to the internal diameter of the pipe, the device comprising a ring external (5) crimping one side (6) is integral with the rigid end piece (4) and the other side (7) coats the end (8) of the pipe threaded on the end piece, the ring being crimped by mechanical compression on said end, the device comprising a flexible sleeve (18) of elastomeric material, of small thickness, said sleeve being located between the rigid end piece (4) and the core (3) of the pipe, characterized in that the sleeve comprises a tubular part of external diameter substantially equal to the internal diameter of the pipe and suitable for being easily inserted into said pipe, and in that it is provided with an end collar (19) for abutment of the sleeve on the one hand on the end face of the pipe (2) and on the other hand on the bottom (21 ) of the ring (5), on the side (6) integral with 1 • rigid end piece.

2. Device according to any one of the preceding claims, characterized in that the length of the sleeve is between about 5 mm and about 40 mm.

3. Device according to any one of the preceding claims, characterized in that the sleeve is of length substantially equal to or slightly less than the length of the end piece.

4. Device according to any one of the preceding claims, characterized in that The thickness of the tubular part of the sleeve is between about 0.1 mm and about 1 mm.

5. Device according to any one of the preceding claims, characterized in that the ring (5) is constituted by a stamped sheet metal socket fixed to the end piece (4) of the tube by shrinking said tube at its end, to block a side of the sleeve in the fold (10) of the tube obtained by friping.

6. Device according to any one of the preceding claims, characterized in that the tube end piece comprises between two and six circular grooves (22) of shallow recess at the sleeve, and advantageously three circular grooves.

7. Device according to any one of the preceding claims, characterized in that the external wall of the tubular part of the sleeve cooperates with gentle friction with the internal wall of the pipe, before crimping.

8. Device according to any one of the preceding claims, characterized in that the sleeve is made of elastomeric material based on a polymer containing butyl chains.

9. Device according to one of claims 1 to 6, characterized in that the sleeve is made of elastomeric material based on a polymer known under the name HNBR.

10. Device according to any one of the preceding claims, characterized in that it comprises means for visual indication of the presence of the sleeve in the pipe after crimping.

11. Device according to claim 10, characterized in that said visual indication means comprise a tongue integral with the collar extending outward substantially in the plane of the underside of said collar.

12. Application of the device according to any one of the preceding claims to leaktight connections of a circuit for circulating a cooling or heating fluid of a motor vehicle.