FR2486721A1 - METHOD FOR PRODUCING WAVEGUIDES AND WAVEGUIDES OBTAINED - Google Patents

Abstract

PROCESS FOR MANUFACTURING WAVE GUIDES AND OBTAINED WAVE GUIDES. CONTINUOUS MANUFACTURING PROCESS OF WAVE GUIDES WITH SMOOTH WALLS AND WAVE GUIDES OBTAINED. THE WAVE GUIDES ACCORDING TO THE INVENTION ARE OBTAINED FROM A METAL TAPE 1 PROFILE AND FOLDED UNTIL THE DESIRED SHAPE IS OBTAINED; EDGES 25, 26 OF THE PROFILED AND FOLDED TAPE ARE WELDED ACCORDING TO A GENERATOR OF THE 4 WAVEGUIDE OBTAINED. THE INVENTION APPLIES TO THE REALIZATION OF THE LONG-LENGTH SMOOTH WALL WAVE GUIDE.

Description

Method of manufacturing waveguides and waveguides obtained

  The present invention relates to a method of continuously manufacturing smooth-walled waveguides, such as those used for radio-relay antenna feeders, and the waveguides manufactured by this method.

  Current waveguides are usually made by assem-

  rigid sections or corrugated or fluted flexible tubes. The realization of waveguides using rigid sections

  presents a number of well-known disadvantages due to the

  the sections and the rigidity of shape of these sections compared to the possibilities offered by these other means of transmission that are the cables. Moreover the end-to-end connection of the sections does not improve the transmission of the signals, it is

  well known that flange assembly generates a stationary wave

important.

  To remedy these drawbacks, waveguides are conventionally used which are constituted either by means of flexible tubes

  fluted or corrugated using semi-rigid tubes.

  The corrugated or corrugated tubes have certain drawbacks and in particular a certain fragility and a significant weakening of the transmitted signals due to the lengthening of the current paths.

  high frequency due to the corrugated or fluted profile of the walls.

  Semi-rigid tubes are conventionally obtained by press extrusion of a ductile metal, such as aluminum; the tube produced by extrusion is normally of circular section and it is known to obtain tubes of different section by crushing the tube. However, the possibilities offered are limited and moreover the crushing of a round profile leads to poorly controlled deformations which do not allow

  not to obtain the desired electrical qualities.

  To overcome these drawbacks, the present invention proposes, on the one hand, a method of manufacturing waveguides making it possible to obtain waveguides of very great length continuously, which can be transported on drums such as cables and which may be cut into sections of any length when

  of use, and secondly the waveguides thus obtained.

-2 -

  According to one characteristic of the invention, the manufacturing process

  cation comprises the following succession of on-line operations: -profiling and folding a metal ribbon to the desired closed shape, so that the edges of the ribbon join, the width of the ribbon being chosen or adjusted so as to be equal to the circumference of the guide to form welding edge to edge of the lips that form the edges of the ribbon after

profiling and folding.

  According to another characteristic of the invention, the waveguide obtained, which is of the smooth-wall type and which is rollable on a drum, is constituted by a profiled and folded metal strip then

  welded along a generatrix of the guide.

  Other objects and advantages of the present invention will be

  described in the following description and in relation to the

figures mentioned below.

  Figure 1 presents a schematic diagram of a chain intended

  to the implementation of the method according to the invention.

  Figure 2 shows a longitudinal section of a formation tube. Figures 3A and 3B show two cross sections of

the training horn.

  FIG. 4 shows an example of a formation roller train. FIGS. 5A to 5F show examples of waveguide section

  obtained by the process according to the invention.

  The production line shown schematically in Figure 1 shows all the elements necessary for the implementation of the waveguide manufacturing method according to the invention. The metal strip 1, conventionally called strip is generally made of copper or aluminum, it is provided in the form of a roll which is mounted on a conventional unwinder 2. The width of the strip 1 is chosen to be equal to the circumference of the waveguide that we want to achieve, it being understood that, if necessary, the desired width is obtained by cutting a standardized ribbon

wider.

  The strip 1 is introduced into a profiling and folding arrangement 3 which ensures gradual shaping of the ribbon

  until the desired shape is obtained.

  The profiling and folding arrangement 3 is symbolized in FIG. 1 by a formation trunk whose shape and operation are recalled in FIG. 2, it should be understood that other equivalent means can be used. to obtain the desired forms of waveguides and in particular this can also be obtained by means of a train of rollers whose shape and

  operation are shown in Figure 3.

  At the output of the arrangement 3, the two lateral edges of the ribbon 1 are joined due to the deformations undergone, they are then welded to one another, in a preferred embodiment, this is obtained by welding to the arc in a neutral atmosphere by means of a welding machine symbolized at 5 in FIG. 1. The weld obtained is preferably produced according to a generatrix of the tube 4 formed by the waveguide, this implies that the ribbon is introduced into the axis of the arrangement 3 and not laterally, this in order to avoid

  to have a helical weld seam.

  In a preferred embodiment of the waveguides according to the invention, the tube 4 formed by edge-to-edge welding of the ribbon 1 is heated by any means and for example by induction, at the melting temperature of a copolymer intended to form an adhesive layer, such

  a copolymer of ethylene-ethyl acrylate.

  For this purpose the tube 4 is sprayed with a shower of particles of the copolymer coming from a tank 7, after having been heated by a heater symbolized by an inductor 6. The particles melt in contact with the tube and form an adhesive layer which is regulated by a die 8. An extruder 9 extrudes on the tube 4 a thick polyethylene sheath with respect to the thickness of the walls of the tube, for example 5 mm of polyethylene on a tube of 2 mm wall thickness , polyethylene coming to adhere to the

  copolymer layer previously arranged.

  The sheathed tube 4 is then cooled, for example in a tank filled with water such as 10, and then wound on a very large drum.

  diameter given the rigidity of the walls of the guide thus formed.

  FIGS. 5A to 5F show the sections of some of the waveguides that can be obtained, in addition to obtaining a circular section, and in particular sections, such as those 4 represented at 5A, 5B, 5C, 5D, which is known to obtain by crushing a tube, without here having the disadvantages due to crushing of the tube. It is also possible to obtain quasi-restangular sections

  such as those presented in 5E and 5F.

  Indeed the metal tube 4 (Figure 5A) is closed by a weld 42 after shaping which leaves some freedom to the two edges that form the lips 26 and 27 until the weld 42 has not met . On the other hand, after welding, the sheath 44 bonded to the tube via the adhesive copolymer 43 reinforces

  holding the waveguide at the curvature.

  Of course, according to the forms to be obtained, it may be preferable

  to use a trunk formation as shown in Figure 2 or a train of rollers as shown in Figure 40 Figure 2 shows an example of trunk formation 3 longitudinal sectional view, this trunk formation 3 has a forming channel 23 which is constituted by a series of truncated c8ne a calibration section 24 ends the trunk, it is removable in the example shown and is fixed by the bolts 28 and 29, the assembly being arranged on a table 30. The ribbon 1 changes from a flat shape to a relatively light curvature as shown

  the cross-section 3A in which the ribbon 1 is shown in FIG.

  laughter of the training trunk at the AA cut.

  The ribbon 1 is projected through the formation channel 23 until it has almost reached its definitive shape, as shown in section BB in the case of a formation channel 23 intended for the production of

oval guides.

  The edges 26 and 27 of the ribbon 1 then form lips which are practically contiguous at the moment when the ribbon 1 enters

  the calibration section 24, from the formation channel 25.

  According to a preferred variant, the ribbon 1 is inserted into the trunk so that the deformations are symmetrical and the edges meet in parallel when the definitive shape of the waveguide is obtained at the level of the sizing section. Of course the welding of the edges which is carried out by the welding machine 5 is preferably carried out to obtain the best possible electrical results while taking into account the imposed obligations.

  by the possible curvatures given to the waveguide during the

  tallations. In the case where the selected section of the waveguide is that of a more or less flattened oval as shown in FIG. 5, the welding is carried out according to a generatrix disposed in a plane of symmetry of the waveguide. plan containing for example the big

  axis of any cross section of the guide.

  For this purpose, efforts are made to maintain the central axis of the ribbon 1 constantly on the same generatrix G of the forming channel 23 during forming, this implies that this generator G is parallel

  in the direction of movement of the ribbon 1 and that the ribbon 1 arrives tangentially

to her.

  In the case presented, this generator G is arranged parallel to

  parallel to the plane of the table 30 which carries the horn 3, the ribbon 1

  moving parallel to this table plane 30.

  Figure 3 shows an example of rollers intended to ensure

  shaping in place of the forming tube.

  In known manner the ribbon 1 must pass through a train composed of successive pairs of rollers such as the rollers 32 and 33 which are mounted on bearings 34 and 35 arranged on shafts 36 and 37 themselves fixed on a frame 38, the shaft 37 being movable under the action of pressure means 39, to ensure a determined pressure on the ribbon 1 which circulates between the rollers 32 and 33. The two rollers of a pair 31 and 32 have complementary shapes which determine the shape that is taken by the ribbon 1 after being

passed between them.

  The use of successive pairs thus makes it possible to obtain the forms

  within well known limits of those skilled in the art.

-6

Claims (7)

  1 / Process for the continuous production of a wall waveguide   smooth, characterized in that it comprises the following succession of opera-   in line: - profiling and folding of a metal ribbon (1) to the desired closed shape, so that the edges of the ribbon join, the width   ribbon being chosen or adjusted so as to be equal to the circumference   fence of the guide to be formed; - edge-to-edge welding of the lips formed by the edges (26, 27) of the   ribbon after profiling and folding.   2 / A method of manufacture according to claim 1, characterized in that it comprises a profiling and folding ribbon by passing through a formation trunk (3) consisting of a series of cone frustums and in that the ribbon (1 ) is inserted in the axis of the horn so that the edges join in a generatrix of the guide wave (4) obtained.   3 / A manufacturing method according to claim 1, characterized in that it comprises a profiling and folding ribbon (1) by passing through a train of rollers (32, 33) in the axis of which the ribbon   is introduced so that the edges join in a general obtained from the waveguide (4).   4 / manufacturing method according to claim 1, characterized in that the succession of on-line operations further comprises: - realization of a thin adhesive layer (43) on the outside of the waveguide by heating the welded guide depositing a powdery adhesive copolymer, melting and spreading this adhesive, - producing a thick polyethylene protective layer (44)   on the outside of the guide, by extrusion.   / Waveguide with smooth walls, characterized in that it consists of a profiled metal strip and folded and welded according to a generator of the guide.   6 / waveguide according to claim 5, characterized in that   the longitudinal weld is located in a long plane of symmetry tudinal of the waveguide.   7 / waveguide according to claim 6, characterized in that the longitudinal weld is located in the longitudinal plane of symmetry of the waveguide which comprises the major axis of any cross section. of that guide.   8 / waveguide according to claim 6 or 7, characterized in that it is covered with a protective sheath of great thickness in polyethylene (44).