FIELD OF THE INVENTION

The present invention relates to a nozzle comprising an elastomer pipe coupled to a tubular end piece made of a synthetic, composite or metallic rigid material in a non-removable manner.

BACKGROUND OF THE INVENTION

It is often necessary, in various fields involving the circulation of fluids, to couple a pipe made of elastomer material, therefore having a certain flexibility, to a rigid tubular end piece which may be, for example, an end piece for coupling to an appliance, or the end of a rigid pipe.

In some applications, a non-removable coupling is required, that is to say, a coupling that ensures that the elastomer pipe cannot be removed from the rigid end piece in a nondestructive manner.

To this end, it is known to connect the elastomer pipe to the rigid end piece and to crimp, around the coupled portion, a metallic sleeve which maintains a certain compression of the elastomer pipe on the tubular end piece.

However, depending on the particular stresses of the target application, the pull-off resistance of the elastomer pipe proves insufficient.

This problem occurs in particular when the rigid end piece is smooth, for example when it is obtained by extrusion, drawing, rolling-welding, swaging, casting.

A local deformation of the end piece could be envisaged, to form, for example, a relief bead in order to better retain the elastomer pipe.

However, the formation of such a bead involves an operation following the production of the end piece and the supply of a specific forming tool, which is detrimental in terms of cost and industrial application. The invention therefore aims to devise a coupling which makes it possible to obtain a better resistance of the elastomer pipe in a pulling direction with respect to the tubular end piece.

Another aim of the invention is also to provide such a coupling which is easy and inexpensive to use in industrial conditions.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with the invention, there is proposed a nozzle comprising an elastomer pipe coupled to a tubular end piece made of a rigid synthetic material in a non-removable manner, said pipe surrounding the end piece along a coupling region.

The term "non-removable" should be understood in this text to mean that the components of the nozzle are not intended to be removed after they have been assembled, and that removal is possible only in a destructive manner.

Said nozzle is characterized in that it comprises, in the coupling region, a ring crimped onto the tubular end piece, the internal wall of said ring being provided with at least one cutting edge and the external wall of said ring being provided with at least one retaining element for the elastomer pipe.

According to other advantageous features of the invention, considered alone or in combination:

- the internal wall of the ring has a concave profile;

- the cutting edge is situated on the side of the end of the end piece;

- the tubular end piece is made of a synthetic, composite and/or metallic rigid material;

- the tubular end piece comprises, in the coupling region, a reinforcing insert in the case where the end piece is made of a synthetic and/or composite material;

- the nozzle comprises a crimping sleeve crimped around the elastomer pipe in the coupling region;

- the tubular end piece is made of an extruded material, preferably polyamide.

Another object of the invention relates to a method for coupling a pipe made of elastomer material and a tubular end piece made of a rigid synthetic material in a non- removable manner, said pipe surrounding the end piece along a coupling region, characterized in that it comprises the following steps:

(a) fitting, in the coupling region, on the tubular end piece, a ring whose internal wall is provided with at least one cutting edge, the ring being crimped onto the end piece so that the cutting edge penetrates into the external wall of the end piece;

(b) introducing the tubular end piece and the ring into the elastomer pipe. Advantageously, the step (a) for fitting the ring includes pressing the portion of the ring opposite the cutting edge against a retaining element and applying, against the ring, a tool having a tapered internal shape so as to deform the ring.

Preferably, when the end piece is made of a synthetic or composite material, said method also comprises, before the step (a) for fitting the ring, a step for introducing a reinforcing insert into the tubular end piece in the coupling region.

Moreover, said method advantageously comprises a step for crimping a sleeve in the coupling region around the elastomer pipe. BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become apparent from the following detailed description, with reference to the appended figures in which:

- Figure 1 shows a partial cross-sectional view of a nozzle according to the invention;

- Figures 2a and 2b illustrate the tool for fitting the ring onto the end piece, respectively in perspective and in cross section.

DETAILED DESCRIPTION OF THE INVENTION

With reference to Figure 1 , the nozzle 1 comprises an elastomer pipe 2 coupled to a tubular end piece 3 by surrounding said end piece along a so-called coupling region.

The pipe 2 is typically an extruded pipe made of an elastomer material, such as, for example, rubber, NBR, silicone, Teflon®.

The tubular end piece 3 is made of a rigid synthetic material, such as, for example, polyamide, polyethylene or even a composite material.

The end piece 3 may also belong to a metal tube consisting of a ferrous or non-ferrous metal.

The tubular end piece is typically the end of an extruded, drawn, swaged, cast or stretched rigid tube; because of this, its external wall is smooth and notably does not include any relief that can constitute a retaining means for the elastomer pipe.

The non-removable coupling of the elastomer pipe 2 to the rigid end piece 3 is obtained by fitting, onto the tubular end piece 3 and in the coupling region, a ring 4 whose internal wall is provided with at least one cutting edge and whose external wall has at least one relief 41 that makes it possible to retain the elastomer pipe.

In the embodiment illustrated in Figure 1 , the ring 4 comprises a first cutting edge 42 arranged on the internal wall 44 of the ring, and a second cutting edge 43 situated at the end of the internal wall of the ring, the two edges being separated by a shoulder, so that the internal diameter of the first edge 42 is less than the internal diameter of the second edge 43.

Preferably, the cutting edges are positioned on the side of the end of the end piece 3.

However, the invention is not limited to this particular ring geometry but can be implemented in a ring provided with at least one cutting edge on its internal wall.

Such a ring is usually employed in the cutting ring couplings which are used for leak- tight connections in hydraulic pipelines. ¹

This type of ring is therefore available on the market in large quantities and at low cost.

Said cutting ring 4 is made of metal material, for example steel of 9SMnPb28K type.

For the ring 4 to remain fastened to the end piece 3, it is crimped onto the end piece 3. This crimping causes the cutting edges 42, 43 to penetrate into the external wall of the end piece 3.

The ring 4 preferably has an internal diameter slightly less than the external diameter of the end piece 3, in particular at the level of the cutting edge 42.

Preferably, the internal wall 44 of the ring 4 is not straight but advantageously has a concave profile, which allows for a better penetration of the edges 42, 43 into the external wall of the end piece 3.

The operation for assembly of the ring 4 on the end piece 3 is performed by deformation using a tool 1 10 having a tapered internal shape 1 1 1 and a retaining element 100, for example in the form of a plate, which are represented in Figure 2a.

As illustrated in Figure 2b, the ring 4 is introduced onto the end piece 3.

The deformation is obtained by placing the end piece 3 in an opening 101 of the retaining plate 100 so that the rear portion of the ring 4 (i.e., the portion opposite the cutting edge 42) is pressed against the plate 100.

The tapered tool 1 10 is then advanced over the end piece 3 in the direction of the arrow so as to apply a force onto the ring 4.

The ring 4 is deformed by closing onto the end piece 3, the cutting edge 42 penetrating into the external wall of the end piece 3.

To avoid the deformation and creep of the end piece 3 under the effect of the crimping of the ring 4, when the end piece is made of a synthetic and/or composite material, a reinforcing insert 5 is advantageously first inserted into the end piece 3, in the coupling region.

The insert 5 is typically a metallic insert whose dimensions are designed to avoid the possibility of the end piece being extracted once it has been inserted therein.

¹ Can you explain how these couplings work? Once the ring 4 is fitted and crimped onto the end piece 3, the assembly is introduced into the elastomer pipe 2, which is preferably surrounded, in the coupling region, with a retaining sleeve 6.

The sleeve 6 is then crimped around the coupling region.

In particular, an intermediate portion of the sleeve 6 is deformed to restrict its section, so that its internal diameter is less than the external diameter of the pipe 2.

The pipe 2 is therefore compressed against the end piece 3.

Moreover, the retaining element 41 of the ring 4, which is advantageously positioned between the end of the tubular end piece 3 and the section restriction of the sleeve 6, allows for a better retention of the pipe relative to the end piece.

When a pulling force is exerted on the newly assembled nozzle 1 , the ring 4 is braced on the end piece 3 by virtue of its cutting edge or edges.

A nozzle is thus obtained whose pulling strength is enhanced ² without its manufacturing cost being significantly increased.

² Do you have results?