Method for assembling the constitutive elements of an antenna reflector

A method of assemblying an antenna having an interlocking support structure with interlocking nodes, and a meshed radiation mirror includes positioning the support structure in a horizontal position, placing the mirror over the horizontally positioned support structure, and pushing glue through the meshes of the mirror to adhere the meshes to adjacent edges of the interlocking support structure. A second embodiment positions a mold in a horizontal position, the mold having a surface form corresponding to a predetermined form of the antenna mirror. Then, the mirror is positioned on the mold surface form. Glue is placed on the edges of the support structure, and the support structure is then deposited on the mirror with the glued edges contacting the mirror. To assemble the support structure, molds are placed around each and every interlocking node. Glue is then forced into the mold to secure the interlocking node.

BACKGROUND OF THE INVENTION 
1. Field of the invention 
The present invention concerns methods for assembling the constitutive 
elements of an antenna reflector, and more particularly, methods for 
securing these elements with respect to one another. 
2. Description of the prior art 
Antenna reflectors generally comprise a fixed carrier structure having a 
predetermined shape, upon which is placed a metallic mirror, the mirror 
forming a surface for reflecting waves. 
The mirror is generally constituted by a material known as an air 
transparent material, i.e. a material which has very little wind 
resistance and which is generally produced in the form of a grid plate or 
expanded metal. Its form determines the radiation characteristic of the 
antenna; this is the reason why it must be shaped very accurately. The 
carrier structure is formed of metal sheets conventionally known as 
"combs" or "ribs", these metal sheets corresponding in shape to the rear 
section of the mirror. They can either be assembled together n order to 
form a resistant framework or be secured in position by another resistant 
framework formed of brackets or grating that supports the whole. 
The methods for assembling the elements of the carrier structure such as 
the metal plates supporting the mirror generally comprise performing a 
riveting or a screwing or soldering in order to secure.these metal plates 
with respect to one another. The assembling method of the mirror upon this 
structure conventionally comprises performing a riveting and using flat 
cover-plates or in using spring staples or also in welding the mirror onto 
the structure. 
The main drawback of these methods results from the fact that pressures are 
exerted on the elements and especially upon the mirror when the staples or 
the rivets are placed in position. These pressures provoke deformations of 
the mirror which modify the radiation characteristics of the antenna. When 
the elements are assembled by welding, the thermal stresses exerted during 
the welding operation will cause undesirable deformations of the mirror. 
SUMMARY OF THE INVENTION 
An object of the present invention is to overcome these drawbacks by 
providing a method for assembling the constitutive elements of the 
reflector mainly characterized in that these elements are assembled by 
gluing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 represents an antenna reflector, the main elements of which are a 
frame 1 and a mirror 2, the mirror being partially represented in this 
drawing. Frame 1 is constituted by an assembly of metal sheets 3 
classically known as combs or ribs. These combs are disposed with respect 
to one another in a manner known per se that provides a rigid support able 
to support the mirror and to resist the stresses imposed by the 
environment or surroundings, especially atmospheric stresses. The front 
section 4 of these combs is obtained in a very accurate manner through 
classical methods so that the mirror may be applied directly onto these 
profiled sections and it thus has the appropriate form providing the 
desired radiation diagram of the antenna. 
Mirror 2, which has been represented, is constituted in this particular 
embodiment by a grid, this mirror being directly applied upon the front 
sections of the combs that confer thereupon the required form. 
According to a first embodiment that is especially adapted to the use of a 
grid, the glue is applied by the front, i.e. by the face that reflects the 
waves. The glue is pushed forward through the meshes of the mirror by 
using, for example, a gun (not represented) in order to coat at the same 
time the edge of the comb and the meshes of the mirror. The metal 
structure that supports the mirror rests, for example, on a horizontal 
plane throughout the whole duration of gluing, so that the mirror does not 
change position. Prior to the hardening or setting of the glue, the glue 
overflowing the mirror is levelled off, for example by using a spatula; 
after the hardening of the glue, the grid plate adheres perfectly to the 
combs and constitutes an assembly having great rigidity and withstanding 
the stress conditions imposed. 
FIGS. 2 and 3 partially represent a transversal cross-section of a rib, the 
grid also being seen from the side. When the glue is injected by using a 
gun, it presents the form of an accumulation 5 which is spread out over 
the surface above the mirror 2 and at the rear around the comb 3. Prior to 
hardening of this glue a levelling off is performed by using a spatula in 
order to obtain a plane surface 6, such as shown in FIG. 3. 0n the 
external edges of the mirror levelling off the surface is performed, as 
well as, on the perimeter of the grid plate in the case where the grid 
plate does not extend beyond the external ribs of the frame. 
The section 4 of the ribs 3 receiving the grid can have a smooth contour. 
It can also, according to an alternative embodiment, comprise regularly 
disposed notches extending along the length of this section. The notches 
can have a cylindrical parallelepipedic form, such as represented 
respectively on FIGS. 4 and 5, these notches providing improved adherence 
of the glue to the sections of the combs. 
FIG. 6 represents a second embodiment of the assembling method according to 
the invention. This second method utilizes a mold 20 that has a surface 
the form of which is identical to that required to confer upon the 
reflector. This FIG. 6 represents a partial cross-section of the reflector 
placed on the mold 20. The mirror 2 is thus positioned on the mold 20, 
this mold being covered with a very thin membrane, which is anti-adhesive. 
The section of the ribs does not need to have very great precision in this 
embodiment since the precision of the contour to be produced upon the 
mirror is conferred by mold 20. The process for obtaining the mold is 
carried out by classical molding methods. The wicks 22, made for example 
from glass fibers are covered with glue and are first of all placed on the 
section of each comb 3. The structure thus equipped is deposited on the 
mirror 2, the wicks 22 coated with glue confining the wires of the mirror. 
After hardening of the glue, the mold can be withdrawn without any 
difficulty, its surface having been covered by the anti-adhesive membrane 
21, constituted, for example, by an anti-adhesive film or varnish. 
The first embodiment applies more particularly to large surface reflectors 
and to mirrors in which the grid or expanded metal is sufficiently 
transparent for the glue to penetrate and reach the combs located to the 
rear of the mat formed by this mirror. 
The second method is more particularly adapted for mirrors having limited 
dimensions, but for which it is necessary to have very high precision of 
the contour or curvature formed by this mirror, although, said second 
method can apply to mirrors of all kinds, i.e. mirrors constituted by grid 
plates, by expanded metal, perforated metal sheets or full metal sheets. 
FIG. 8 schematically represents a carrier structure that comprises vertical 
combs 30 and horizontal combs 31 interlocked with respect to one another, 
so as to form a stiff structure. Each interlocking unit forms a node 32. 
The method according to the invention also consists in gluing the combs 
together, at the site which they interlock or where they form nodes 32. 
FIG. 9 represents the detail of a node formed by interlocking two combs 30, 
31. The method thus consists in injecting glue into this interlocking 
area. In order to do this, a mold 35 constituted of two parts 36, 37 is 
used which allows it to be secured onto the combs surrounding the node 32 
so as to constitute a recess into which the glue can be injected. 
The mold 35 is present in the form of two semi-cylinders 36, 37 both closed 
at the same end. Each semi-cylinder, such as the semi-cylinder 37 
represented in FIG. 10, comprises two lugs 38, 39 extending along the 
length of the two edges defining the semi-cylinder. 
Lugs 38 and 39 comprise respectively a finger 40 and 41 and respectively a 
hole 50, 51. Finger 40 is placed at one end of lug 38 and hole 50 at the 
other. Finger 41 is placed at one end of lug 39 and hole 51 is placed at 
the other end opposite with the hole and the finger of lug 38. For the 
other half-mold (not represented) the positions of fingers 40, 41 and 
holes 50, 51 are inverted. The lugs provided with fingers in fact secure 
the semi-molds on either side of one of the two combs (for example, the 
comb 30), that comprise holes adapted to receive these fingers 40, 41. 
Therefore, when the two parts of the mold are placed on either side of 
this comb, these two parts constitute a recess closed around the node, 
such as that represented in FIG. 9. 
The two parts of the mold 35 possess a slot 42 that allows entry of the 
other comb (comb 31). The section of the combs is engaged inside the slots 
42 and is blocked by means of a resilient boss 43 that is housed within a 
hole 44 for this purpose on the opposite side of the comb. 
FIG. 11 represents a mold 60 allowing the gluing of two combs forming an 
angle between them at the periphery of the structure. This mold comprises 
two fastening lugs 38 and 39 that allow it to be secured during gluing, 
respectively on the horizontal comb and on the vertical comb that form the 
angle A. These lugs are secured by means of screws tightened by using nuts 
62. It comprises a plate 63 and a plate 64 (placed on the rear plane of 
FIG. 11) integral between each other which constitute an angle cavity into 
which the glue can be injected. 
FIG. 12 represents a mold allowing the gluing of two combs forming two 
angles between them at the periphery of the structure. This mold is 
constituted by a semi-mold 36 such as described in FIG. 10. The means for 
securing the mold are constituted by screws tightened by nuts 62. 
The glues selected are glues that are mechanically resistant, have a good 
coefficient of viscosity and have a good aptitude.to ageing. 
For assembling the mirror on the carrier structure, it is for example 
possible to use a Redux 410.RTM. type resin commercially available from 
CIBA GEIGI, and for assembling the elements of the carrier structure, it 
is possible to use for example a CY 219.RTM. type resin, also commercially 
available from CIBA GEIGI.