FR2465191A1 - METHOD FOR MANUFACTURING A SET OF PROXIMITY ROCKET AND PROXIMITY ROCKET OBTAINED BY THIS PROCESS - Google Patents

Abstract

THIS ROCKET INCLUDES A SET OF ELECTRODES 21, 22 SEPARATES FROM A SCREEN BY A DIELECTRIC LAYER FORMED OF TWO PARTS, A FIRST PART ASSOCIATED WITH THE SCREEN AND A SECOND PART ON WHICH THE SET OF ELECTRODES 21, 22 IS FIXED ACCORDING TO A PREDETERMINED CONFIGURATION.

Description

1 2465191

  The present invention relates to improvements

  brought to proximity rockets for ballistic missiles.

  Proximity rockets are mounted on beacons

  ticks to detect the presence of a target and to ignite an explosive charge carried by the device when it is

close enough to the target.

  Proximity flares operating by capacitive effect include transmit and receive electrodes and associated electronic control circuits and, in order for the rocket to operate effectively it is necessary to shield the electrodes from the electronic circuits by a screen

  which is separated from the electrodes by a dielectric layer.

  The areas of the screen and the electrodes and their relative positions must be arranged with very close tolerances if it is desired to avoid a fault in the ignition of the charge or untimely operation. In addition, small changes in the effective area or in the relative positions of the electrodes can adversely affect the associated electronic control circuits which would necessitate providing control over a much larger range than would otherwise be necessary and correspondingly reduce efficiency and reliability

of the rocket.

  According to a construction of the prior art, the electrodes are placed separately on a dielectric layer after its formation around the screen. This has the disadvantage that the relationship between the electrodes cannot be controlled with

precision and that in operation parasitic signals are

  plicated to the control electronics.

  The invention aims to remedy this drawback.

  It therefore relates to a method for producing a type of proximity rocket comprising a set of electrodes separated from a screen by a dielectric layer, characterized in that it consists in fixing the set of electrodes to a first

  part of the dielectric layer according to a predeter configuration-

mined and then connect the electrode assembly and the material

dielectric to a screen.

The invention also relates to a proximity rocket assembly, characterized in that it comprises an electrode assembly separated from a screen by a dielectric layer formed of two parts, a first part associated with the screen and a second

2 4'65 191

  part on which the following set of electrodes is fixed

a predetermined configuration.

  Other characteristics and advantages of the invention

  will appear during the description which follows made in

  reference to the appended drawings, given solely by way of example and in which: - FIG. 1 is a perspective view of a first stage of manufacturing a screen of a first embodiment of a proximity rocket assembly

- Fig. 2 is a perspective view of an ex hat

  tip used for manufacturing the first embodiment of rocket; - Fig. 3 is a perspective view of a stage of manufacturing a first part of a dielectric layer of the first embodiment of a rocket - FIG. 4 is a developed plan view of a second part of a dielectric layer and of an electrode assembly of the first embodiment of a rocket; - Fig. 5 is a perspective view of the dielectric layer and of the electrode assembly of FIG. 4 which has been given a frustoconical shape; - Fig. 6 is a perspective view of a mold showing the molding of an outer sheath of the first embodiment of the rocket;

- Fig. 7 is a side elevational view, partially

ment in section of the first completed rocket embodiment; - Fig. 8 is a side elevation view of a second embodiment of a proximity rocket; and - Fig. 9 is a front view of the entire

Fig. 8.

  Referring first to FIG. 1, a split screen

  conical 11 (Fig. 2) is produced by winding with contiguous turns

  a thin tinned copper wire 12 on a conical mandrel 13 (shown

smelled in mixed lines).

The mandrel 13 is precision machined to present the required taper. The wire winding 12 is then coated with a

  flux containing tin powder and heated to mix

gamer the tin in the flux with that of the wire 12 and thus fix the adjacent turns together to form a rigid frustoconical tube. The heating is continued while the 3 in 'A 6 5. 191 excess tin and flux flows from the surface of the wire 12. This method of manufacturing the screen 11 makes it possible to obtain a screen having a good internal finish (since the wire 12 is held tightly against the surface of the mandrel 13) and of a precise thickness which is approximately equal to the diameter of the wire 12 used. Referring next to Figs. 2 and 3, a little hat

  conical 14 made of plastic forming a carcass is made of

  rolling a sheet of plastic material 15 of the same thickness as

that of the finished screen 11 around the tip of the conical mandrel.

The joint between the edges of the sheet 15 is produced by means of a very thin adhesive tape 17 made of plastic. Hat 14 is

  fixed to the small end diameter of the screen there by an adhesive tape

plastic sif 31 to form the conical carcass.

  The conical element defined by the screen 11 and the cap 14 is then supported by the conical mandrel 13. A first part

  a dielectric layer 18 is then formed around the surface

this external of the conical assembly by winding in contiguous turns

a nylon thread 19 around the screen there and the hat 14. The thick

the nylon 19 thread which is wound in a helix, determines

  lesson specifies the thickness of the first part of the dielect layer

  trique 18. This is a subset of the screen.

  Referring to FIG. 4, a set of compressed electrodes

  nant a transmitting electrode 21 and two receiving electrodes 22

  is made in the form of a printed circuit on a dielect sheet

  sheet 20 coated with copper. The dielectric sheet 20 constitutes the second part of the dielectric layer. An image of the electrode assembly is formed on the copper coating by reduction

  photograph of an enlarged model to obtain maximum precision

male and the copper coated dielectric sheet 20 is then pickled according to this image. The dielectric sheet 20 has the form

of a developed truncated cone and, after trimming, the leaf is red

  lée to form a frustoconical sub-assembly 23, the edges 24 of the sheet 20 being assembled by a thin adhesive tape of material

  plastic 25. As can best be seen in FIG. 5, electro-

  of emission 21 is arranged towards the tip of the sub-assembly 23 while the reception electrodes 22 are located on the side of

its base.

The dimensions of the sub-assembly 23 are such that it fits

te closely on the first part of the dielectric layer 18.

4 2 A 6 5191

The first part of the dielectric layer 18 is impregnated with a

appropriate adhesive and the sub-assembly 23 is fitted onto the screen.

  The adhesive is then treated to stick together the first and

  second parts 18 and 20 of the dielectric layer.

  the electrodes 21, 22 are tinned and small caps of

  cork 26 are fixed on these areas at suitable points so

re to facilitate the connection of electrodes 21-, 22 to the equipment

associated electronics.

  The entire screen 11 with the dielectric layer 18, 20 and the electrodes 21, 22 is inserted into a mold 27 containing the resin shown in FIG. 6. The resin is then treated or it is allowed to harden so as to form a protective layer or sheath 28 coating the assembly. According to a variant, the sheath 28 can be formed by an injection molding process. The plugs 26

have a thickness such that they fit between the electro-

  21, 22 and the mold 27 so as to provide small holes in

  the molded sheath when the plugs 26 are removed.

  Once the assembly has been removed from the mold 27, the base of the sheath 28 is deburred to bring it to the required dimensions and the cork stoppers 2'6 are removed. The sheath 28 ensures that the screen 11, the dielectric layer 18 and the electrodes 21, 22 are held in

fixed relative positions.

  The completed proximity rocket assembly is shown in Fig. 7. After formation of the assembly, the electronic control circuits of the rocket are arranged inside the latter. Then the assembly is attached to the front end of a ballistic missile of

so that the assembly constitutes the conical nose of the machine.

Then referring to Figs. 8 and 9, a second embodiment of a proximity rocket assembly is shown, the parts common to these figures and to FIGS. 1 to 7 with the same references. In this embodiment, the second part of the dielectric layer carries a fourth electrode 32 of shape

  conical, which covers the nose of the proximity rocket assembly.

This second embodiment of rocket is constructed in the manner

described above with reference to Figs. 1 to 7.

  Note that the screen can be manufactured in a way

  different from that described above with reference to the drawings.

  The screen can be made by electroforming, metal pushing

  tal, metal spraying, injection molding, rolling up a metal sheet or machining. In addition, the first part of the 21i 65191

  dielectric layer 18 can be produced by injection molding

  tion, molding of compounds, using a single or composite sheet, by spraying or dip coating

or by electrophoresis.

  It will further be noted that it is not necessary to form the screen 11 before the first part of the dielectric layer 18. The first part of the dielectric layer 18 can be formed by any of the methods described above and the screen it can then be formed on the surface of layer 18

by any of the methods described.

  In addition, it is not essential to form the di-

  electric in two parts. The object of the invention is to fix the electrodes 21, 22 in fixed relative positions before the construction of the proximity rocket assembly. This can be achieved by attaching the electrodes 21, 22 to a sheet of material

dielectric with required characteristics (in this case as a representation

felt in FIG. 4) by giving the sheet a conical or other desired shape and then forming the screen assembly as a metallic screen on the inner surface of the layer

dielectric.

Finally, note that the electrodes 21, 22 can be formed on the dielectric layer other than by printed circuit techniques. The electrodes 21, 22 can be plated on

  the layer or pickled after blocking or be formed by spraying

  metal station with appropriate masks.

  It has been found that the methods of construction of the assembly as described above with reference to the appended drawings make it possible to obtain close tolerances for the zones and the relative positions of the screens and electrodes and that they are

reproducible with these narrow tolerances.

  The assembly produced according to the abovementioned methods, incorporated into a proximity rocket makes it possible to obtain a rocket which operates in a reliable and precise manner because the variations in the relative positions between the electrodes and the screen are reduced if not totally avoided. . In addition, since the screen and electrode assembly, when provided with a sheath, can itself

define the conical nose of a ballistic device, we obtain

  aunts weight reductions of the machine and maximum space in the

tapered nose to house the control circuits

electronic.

6 E-'191R

Claims (23)

R E V E N D I C A T I 0 N S   1. Method of manufacturing a rocket set of pro-   ximity of the type comprising a set of electrodes separated from a   screen by a dielectric layer, characterized in that it consists   te to fix the electrode assembly to at least a part of the dielectric layer according to a predetermined configuration and to then connect the electrode assembly and the dielectric material than on a screen. 2. Method according to claim 1, characterized in that it consists in forming the dielectric layer in two parts, a first part associated with the screen to form it   and a second part to which the electrode assembly is fixed. 3. Method according to claim 2, characterized in that it consists in forming the second part of the dielectric layer in the form of a flat sheet of dielectric material, in fixing the electrode assembly on the sheet of dielectric material and then to connect this second part of the dielectric layer   to said first part of the dielectric layer.   4. Method according to claim 3, characterized in that the stage of fixing the set of electrodes to the sheet of dielectric material consists in coating the sheet of dielectric material with a conductive coating and in etching with a   photochemical process the coating to form the electrical assembly trodes.   5. Method according to any one of claims 1 to   4, characterized in that it consists in forming the set of electrodes   in the form of several separate electrodes. 6. Method according to claim 2, characterized in that it consists in forming the screen and then in forming the first   part of the dielectric layer on the screen. 7. Method according to claim 6, characterized in that the stage of formation of the screen consists in winding a conducting wire on a mandrel, the adjacent turns of the winding   being in contact and then connecting the turns together to cons- tituer a rigid screen. 8. Method according to any one of claims 6   and 7, characterized in that the stage of formation of the first   part of the dielectric layer consists of winding a dielectric wire electric around the screen.   9. Method according to claim 8, characterized in that the screen is frustoconical and in that it also consists in   connect a conical carcass to the end of the smaller diameter   meter of the screen and wind the dielectric around the screen and the carcass to obtain the first part of the layer dielectric in conical form. 10. Method according to claims 3 and 9 considered   as a whole, characterized in that the sheet of dielectric material in the form of a developed truncated cone, and in that   that it further consists in rolling up the sheet of dielectric material.   which carries the set of electrodes in the form of a truncated cone and to fix said second frustoconical part to the first part conical of the dielectric layer. 11. Method according to claim 10, characterized in that it consists in covering the first conical part of the dielectric layer with a dielectric adhesive before fixing said second   frustoconical part of dielectric material thereon.   12. Method according to any one of claims 6   or 7, characterized in that the stage of formation of the first part of the dielectric on the screen consists in coating a surface   of the screen with dielectric material.   13. Method according to claim 2, characterized in that it consists in forming the first part of the dielectric layer. and then form the screen. 14. Method according to claim 13, characterized in that   that the stage of formation of the screen consists in depositing a coating   conductively on the surface of the first part of the dielectric layer.   15. Method according to any one of claims 1 to 14, characterized in that it consists in covering the set of electrodes with a protective sheath once the first and second parts of the dielectric layer have been connected together. 16. The method of claim 15, characterized in that the step of coating the electrode assembly consists of inserting said assembly into a mold containing a resin and then allowing the resin to harden to form said protective layer.   17. Method according to any one of claims 15 or 16, characterized in that it consists in leaving areas of 8, '191 the set of electrodes not covered by the protective layer. 18. Proximity rocket assembly, characterized in that it comprises a set of electrodes separated from a screen by a dielectric layer formed by two parts, a first part associated with the screen and a second part on which the together   of electrodes is fixed according to a predetermined configuration. -   19. The assembly of claim 18, characterized in that it is conical or almost conical, the screen being formed by an inner frustoconical layer of conductive material, the dielectric layer being conical or nearly conical and covering the screen and the set of electrodes covering the dielectric layer. 20. Rocket assembly according to any of the re- vendications 18 and 19, characterized in that the screen is made up   by a series of turns of a conducting wire linked together.   21. Set of rockets according to any one of claims 18 to 20, characterized in that the first part   of the dielectric layer is formed by a series of turns contiguous with a dielectric wire. 22. Rocket assembly according to claim 19 taken together with any of claims 20 and 21,   characterized in that the electrode assembly comprises three zones of conductive material, a first frustoconical zone towards the outside   mite of smallest diameter of the assembly and two second zones extending axially over the same length and having approximately the shape of half trunks of cones.   23. Rocket assembly according to claim 22, characterized in that a fourth zone of conductive material is provided which is conical and which covers the end of all.