FR2856335A1 - Manufacture of extruded plastic hosepipe with lengthwise inner ribs has pipe ends made without ribs to allow for fitting accessories - Google Patents

Abstract

The extruded hosepipe (1) with inner lengthwise ribs (3) is made e.g. in lengths of 25 and 50 m. Each pipe length has a zone (5) at each end that has no ribs to allow accessories such as connectors (2) to be fitted. The the extrusion operation can include a stage in which the production of the ribs is halted briefly, or the extruded ribs can be removed subsequently by a rotary bladed tool to leave a smooth inner surface.

Description

The invention relates to a method for manufacturing a garden hose.

flexible.

  It also relates to the product obtained as well as to the means for implementing the process.

  The garden hoses include one or more flexible cylindrical casings made of plastic material.

  These pipes are generally produced by extrusion.

  To connect these pipes to the distribution network or to an appliance, the end of the pipe is fitted with a connection system.

  This connection system comprises on the one hand a male part intended to come into engagement inside the pipe and on the other hand connection means adapted to the distribution network or to the device to be connected.

  The end of the pipe covers the male part of this connection system by tightening it slightly and a hose clamp comes around the whole to firmly apply the internal face of the pipe to the external face of the male part in order to obtain a seal.

  Many variants of connection systems exist, but the principle of the junction between the end of the pipe and the connection system incorporates the above characteristics, namely a male part engaged in the tubular end of the pipe.

  These pipes have a constant section along their longitudinal axis.

  These flexible pipes are generally armed with one or more wires.

  This armor is trapped between two layers of material.

  The wire constituting the armor can be wound in the form of a helix around an envelope.

  It is also possible to form a knit with the said thread.

  This gimped or knitted thread makes it possible to resist in particular the pressure of the water but also tends to prevent the hose from pinching and then inducing a cut in the circulation of water.

  This second function, however, remains ineffective.

  To solve this problem of cutting off the circulation of water, it is then known to provide longitudinal ribs inside the pipe.

  So when you walk on the pipe or if you roll on it, the pipe crashes but due to the presence of these ribs, spaces are preserved between the ribs and therefore allow minimal circulation of the fluid.

  Such a solution is interesting but then constitutes a problem for the installation of the male part of a connection system.

  Indeed, even when using connection systems, the male part of which is adapted to the internal configuration of the pipe, it is not possible to obtain a good seal.

  For this reason the use of these pipes is almost non-existent.

  The invention proposes to provide a solution to the problem notably mentioned above.

  To this end, the invention relates to a method of manufacturing by extrusion of a flexible pipe comprising a cylindrical casing and longitudinal internal ribs, this manufacturing process being characterized in that one constitutes at the end of the pipe a cylindrical zone of constant thickness.

  The invention also relates to the flexible pipe as well as the means for implementing the method.

  The invention will be clearly understood with the aid of the description below made by way of nonlimiting example with regard to the drawing which represents schematically: FIG 1: view in longitudinal section of a pipe according to the prior art.

  FIG 2: view in longitudinal section of a pipe according to the invention.

  FIG 3: section along 111-111 of figure 2 FIG 4: section along IV-IV of figure 2 Referring to the drawing, we see a flexible pipe 1.

  This is intended to be equipped with a connection device 2 or at least a male part 2A coming to engage in the tubular end 1A of this pipe.

  In known manner, this pipe has internally longitudinal ribs 3 parallel to its longitudinal axis 4.

  This pipe can be armed with a wrapped or knitted wire.

  It can be made up of several layers.

  To make this pipe, an extrusion or injection machine is generally used.

  According to the invention, at the latest before installation of the connection device 2, a cylindrical zone 5 of constant thickness is formed at each end of the pipe.

  This cylindrical zone 5 of constant thickness is therefore devoid of ribs 3.

  The internal diameter of this zone 5 is substantially equal to the external diameter of the male part.

  To do this in a first variant, we remove the ribs 3 previously obtained during the manufacture of the pipe.

  Different means and methods are possible.

  For example, the end of the pipe is optionally placed in a template sleeve and a rotary or alternative knife device in the manner of a reamer removes the ribs until a smooth or substantially smooth surface is obtained.

  This removal can be achieved by one or more passages of a tool, the blades of which will be changed to achieve the required result.

  The tool used and / or the method will depend in particular on the shape of the rib, its height and the quality of the material used to manufacture the pipe.

  In a second variant of the method, during the manufacture of the pipe by extrusion, the manufacture of these ribs is temporarily interrupted over a determined length.

  This can be done easily by providing at least one drawer on the supply of the extrusion head of the extruder as it can be done on coextrusion machines.

  This or these drawers function as valves to interrupt the supply of material at the part of the extrusion head which corresponds to the production of the ribs.

  These pipes are continuously manufactured and then cut to the chosen length, which is generally 25 meters or 50 meters.

  In this zone where the sectioning will be done to obtain pipes of determined lengths, it is therefore sufficient to interrupt the manufacture of the ribs.

  Thus it then becomes possible to use standard connection devices without fear of a leak. 4 4 '

Claims (6)

  1. Method of manufacturing by extrusion of a flexible pipe (1) comprising a cylindrical envelope and longitudinal internal ribs (3), this manufacturing process being characterized in that an area (at the end of the pipe) is formed ( 5) cylindrical of constant thickness.   2. A method of manufacturing a flexible pipe by extrusion according to claim 1 characterized in that during the manufacture of the pipe by extrusion, the manufacture of these ribs is temporarily interrupted over a determined length.   3. A method of manufacturing by extrusion of a flexible pipe according to claim 1 characterized in that it removes the ribs (3) previously obtained during the manufacture of the pipe.   4. A method of manufacturing by extrusion of a flexible pipe according to claim 3 characterized in that one uses a rotary or alternative knife device in the manner of a reamer to remove the ribs until a smooth or substantially surface is obtained. smooth.   5. Flexible pipe (1) comprising a cylindrical envelope and longitudinal internal ribs (3) characterized in that it comprises at the end of said pipe a cylindrical zone (5) of constant thickness.   6. Means for implementing the method according to claim I or 2 comprising an extruder with its extrusion head, these means being characterized in that they comprise at least one drawer intended to shut off the feed to the head. 'extrusion.