CA1152636A - Composite structural member for antenna - Google Patents
Composite structural member for antennaInfo
- Publication number
- CA1152636A CA1152636A CA000364143A CA364143A CA1152636A CA 1152636 A CA1152636 A CA 1152636A CA 000364143 A CA000364143 A CA 000364143A CA 364143 A CA364143 A CA 364143A CA 1152636 A CA1152636 A CA 1152636A
- Authority
- CA
- Canada
- Prior art keywords
- leg
- outer element
- structural member
- composite structural
- elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/14—Reflecting surfaces; Equivalent structures
- H01Q15/141—Apparatus or processes specially adapted for manufacturing reflecting surfaces
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Aerials With Secondary Devices (AREA)
Abstract
ABSTRACT
A composite structural member and a method for its production which are particularly useful when such composite structural member is to have a non-linear shape in its longitudinal axis. The composite struc-tural member is comprised of a number of "U" shaped elements, flexible in their longitudinal axis, which are arranged in two groups of superposed elements, each group forming a comb-like structure having its leg portions facing each other and being closely engaged and firmly secured together. The method of production consists of placing a first element in contact with a rigid form having the required shape and successively laying the other element over the first element with their leg portions facing a direction opposite to that of the leg portions of the previously laid element and finally securing all the elements together before the composite structural element is released from the form.
A composite structural member and a method for its production which are particularly useful when such composite structural member is to have a non-linear shape in its longitudinal axis. The composite struc-tural member is comprised of a number of "U" shaped elements, flexible in their longitudinal axis, which are arranged in two groups of superposed elements, each group forming a comb-like structure having its leg portions facing each other and being closely engaged and firmly secured together. The method of production consists of placing a first element in contact with a rigid form having the required shape and successively laying the other element over the first element with their leg portions facing a direction opposite to that of the leg portions of the previously laid element and finally securing all the elements together before the composite structural element is released from the form.
Description
11~2636 This invention relates to novel composite I structural members and to a method of manufacture of ¦ such members.
The production of non-linear structural members requires special methods, for example, casting, custom-cutting or other expensive and time consuming methods.
The instant invention permits the production of non-linear structural members in a much easier and cheaper way and is particularly well-adapted for the production of parabolic antenna ribs exhibiting excellent characteristics.
This invention is also useful when straight struc-tural members are required, especially when they are to be assembled on the site.
When non-linear structural members are required, a number of longitudinally extending, relatively flexible "U" shaped elements are used to form a structural member having the required shape and strength.
A plurality of "U" shaped inner elements are also used. Each has a first leg and a second leg. The distance separating the first leg from the second leg is slightly larger than the total thickness of said first leg and second leg.
Two "U" shaped outer elements are used. Each has a third leg and a fourth leg. Said third leg is preferably longer than the fourth leg. The fourth leg is of the same thickness as said second leg. The distance separating said third leg and said fourth leg is slightly larger than the thickness of said second leg.
A first outer element is placed on a rigid form having the required shape and is forced to adopt the shape of said form. A first inner element having its legs point-ing in a direction opposite those of said first outer ele-ment, is forced into engagement with said first outermost element. A second inner element having its legs pointing in the same direction as those of said first outer element is forced into engagement with said first inner element.
Each remaining inner element is then successively forced into interlocking engagement with the previously placed inner element.
~152636 ~ - 2 -;
A second outer element is then forced into interlocking engagement with the last inner element to have been placed.
~rhe various elements are firmly held together by means of rivets, bolts, screws, glue, epoxy or other means while they are still maintained in close contact with said form.
When released, the composite structural member retains the exact shape of the fvrm and is ready to use.
These and other advantages of the invention will be hereinafter described and for purposes of illustration, but not of limitations, an embodiment of the invention is shown in the accompanying drawings.
Figure 1 is a plan view of a parabolic antenna comprising an embodiment of the present invention;
Figure 2 is a partial section along line II-II
of Figure l; and, Figure 3 is a partial section along line III-III
of Figure 1.
As seen in Figure 1, parabolic antenna 10 is made up of a plurality of identical segments 11. These segments are fixed to a central circular plate 12 and to an outer rim 16. Segments 11 are also held together by appropriate means which are not shown. Emitter and/or receiver 13 is held in place by known means.
When parabolic antennas of small radius are made, it is possible to preform the antenna segments out of sheet metal. These segments are then welded together to form the parabolic antenna. However, in large diameter parabolic antennas it is either technically impossible to do this or the costs involved are prohibitive. As shown in Figure 2, the antenna segments 11 are made of sheet material 15 which is given the proper parabolic shape by fixing it to a rib 14 having the proper parabolic shape.
Such ribs 14 may be very expensive to manufacture when known methods are use~.
However, the cost of manufacturing parabolic antenna segment ribs such as shown at 14 in Figure 2 may be greatly reduced when the present invention is used.
~152636 Figure 3 is a cross-section of rib 14 made accord-ing to the present invention. Rib 14 is made up of a num-ber of "U" shaped elements. The uppermost element 24 and the lowermost element 23 are identical. All the elements placed between elements 23 and 24, including elements 21, 22, 25 and 26, are identical. Outer elements 23 and 24 are slightly different from the inner elements (e.g. element 21).
Each inner element (e.g. element 21) has a first leg (e.g. leg 41) and a second leg (e.g. leg 42). The distance separating the first leg from the second leg is slightly larger than the total thickness of the first and second legs.
Each outer element (e.g. element 24) has a longer leg (e.g. leg 31) and a shorter leg (e.g. leg 32). The shorter leg is of the same thickness as the second leg.
The distance separating said longer leg from said shorter leg is slightly larger than the thickness of said second leg.
As can be seen in Figure 3, all the elements making up rib 14 are arranged so that all their legs point inwardly of rib 14 and in such a way that they are all inter-connected together.
The "U" shaped elements may be made of any material exhibiting sufficient flexibility around the "X" axis to allow rib 14 to be manufactured according to the method described hereunder, but sufficiently rigid to provide rib 14 with adequate strength.
Rib 14 was made according to the following method:
a) leg 31 of element 24 is placed on a rigid form (not shown) having the required parabolic shape and element 24 is shaped to conform perfectly to said form;
b) leg 41 of element 21 is placed between legs 31 and 32 of element 24 by forcing element 21 to conform per-fectly with said element 24;
! C) leg 43 of element 22 is placed between leg 32 of element 24 and leg 42 of element 21 by forcing element 22 to conform perfectly with said elements 24 and 21;
d) steps b) and c) are repeated with other inner elements as many times as required to provide the required strength in rib 14;
~152636 e) element 23 is placed on top of the others as shown in Figure 3;
f) while the various elements are still firmly held together, a number of holes are pierced through rib 14 in the "Y" axis at different points along its longit-udinal axis and, ; g) securing means are placed in the holes and tightened to secure the various elements firmly together.
When rib 14 is released from said form, it thus retains the exact shape of such form.
Although the invention has been illustrated in association with a parabolic antenna, it is evident that it is applicable to a great number of structural elements especially those having special shapes. Similarly, while the invention has been illustrated in association with securing means which require to be tightened, it is clearly within the ambit of the invention to use other types of securing means such as glue, epoxy, etc.
From these examples, it can be seen that the invention should not be limited to the specific embodiment illustrated, as many other variations may be made, which do not affect the substance of the invention.
The production of non-linear structural members requires special methods, for example, casting, custom-cutting or other expensive and time consuming methods.
The instant invention permits the production of non-linear structural members in a much easier and cheaper way and is particularly well-adapted for the production of parabolic antenna ribs exhibiting excellent characteristics.
This invention is also useful when straight struc-tural members are required, especially when they are to be assembled on the site.
When non-linear structural members are required, a number of longitudinally extending, relatively flexible "U" shaped elements are used to form a structural member having the required shape and strength.
A plurality of "U" shaped inner elements are also used. Each has a first leg and a second leg. The distance separating the first leg from the second leg is slightly larger than the total thickness of said first leg and second leg.
Two "U" shaped outer elements are used. Each has a third leg and a fourth leg. Said third leg is preferably longer than the fourth leg. The fourth leg is of the same thickness as said second leg. The distance separating said third leg and said fourth leg is slightly larger than the thickness of said second leg.
A first outer element is placed on a rigid form having the required shape and is forced to adopt the shape of said form. A first inner element having its legs point-ing in a direction opposite those of said first outer ele-ment, is forced into engagement with said first outermost element. A second inner element having its legs pointing in the same direction as those of said first outer element is forced into engagement with said first inner element.
Each remaining inner element is then successively forced into interlocking engagement with the previously placed inner element.
~152636 ~ - 2 -;
A second outer element is then forced into interlocking engagement with the last inner element to have been placed.
~rhe various elements are firmly held together by means of rivets, bolts, screws, glue, epoxy or other means while they are still maintained in close contact with said form.
When released, the composite structural member retains the exact shape of the fvrm and is ready to use.
These and other advantages of the invention will be hereinafter described and for purposes of illustration, but not of limitations, an embodiment of the invention is shown in the accompanying drawings.
Figure 1 is a plan view of a parabolic antenna comprising an embodiment of the present invention;
Figure 2 is a partial section along line II-II
of Figure l; and, Figure 3 is a partial section along line III-III
of Figure 1.
As seen in Figure 1, parabolic antenna 10 is made up of a plurality of identical segments 11. These segments are fixed to a central circular plate 12 and to an outer rim 16. Segments 11 are also held together by appropriate means which are not shown. Emitter and/or receiver 13 is held in place by known means.
When parabolic antennas of small radius are made, it is possible to preform the antenna segments out of sheet metal. These segments are then welded together to form the parabolic antenna. However, in large diameter parabolic antennas it is either technically impossible to do this or the costs involved are prohibitive. As shown in Figure 2, the antenna segments 11 are made of sheet material 15 which is given the proper parabolic shape by fixing it to a rib 14 having the proper parabolic shape.
Such ribs 14 may be very expensive to manufacture when known methods are use~.
However, the cost of manufacturing parabolic antenna segment ribs such as shown at 14 in Figure 2 may be greatly reduced when the present invention is used.
~152636 Figure 3 is a cross-section of rib 14 made accord-ing to the present invention. Rib 14 is made up of a num-ber of "U" shaped elements. The uppermost element 24 and the lowermost element 23 are identical. All the elements placed between elements 23 and 24, including elements 21, 22, 25 and 26, are identical. Outer elements 23 and 24 are slightly different from the inner elements (e.g. element 21).
Each inner element (e.g. element 21) has a first leg (e.g. leg 41) and a second leg (e.g. leg 42). The distance separating the first leg from the second leg is slightly larger than the total thickness of the first and second legs.
Each outer element (e.g. element 24) has a longer leg (e.g. leg 31) and a shorter leg (e.g. leg 32). The shorter leg is of the same thickness as the second leg.
The distance separating said longer leg from said shorter leg is slightly larger than the thickness of said second leg.
As can be seen in Figure 3, all the elements making up rib 14 are arranged so that all their legs point inwardly of rib 14 and in such a way that they are all inter-connected together.
The "U" shaped elements may be made of any material exhibiting sufficient flexibility around the "X" axis to allow rib 14 to be manufactured according to the method described hereunder, but sufficiently rigid to provide rib 14 with adequate strength.
Rib 14 was made according to the following method:
a) leg 31 of element 24 is placed on a rigid form (not shown) having the required parabolic shape and element 24 is shaped to conform perfectly to said form;
b) leg 41 of element 21 is placed between legs 31 and 32 of element 24 by forcing element 21 to conform per-fectly with said element 24;
! C) leg 43 of element 22 is placed between leg 32 of element 24 and leg 42 of element 21 by forcing element 22 to conform perfectly with said elements 24 and 21;
d) steps b) and c) are repeated with other inner elements as many times as required to provide the required strength in rib 14;
~152636 e) element 23 is placed on top of the others as shown in Figure 3;
f) while the various elements are still firmly held together, a number of holes are pierced through rib 14 in the "Y" axis at different points along its longit-udinal axis and, ; g) securing means are placed in the holes and tightened to secure the various elements firmly together.
When rib 14 is released from said form, it thus retains the exact shape of such form.
Although the invention has been illustrated in association with a parabolic antenna, it is evident that it is applicable to a great number of structural elements especially those having special shapes. Similarly, while the invention has been illustrated in association with securing means which require to be tightened, it is clearly within the ambit of the invention to use other types of securing means such as glue, epoxy, etc.
From these examples, it can be seen that the invention should not be limited to the specific embodiment illustrated, as many other variations may be made, which do not affect the substance of the invention.
Claims (9)
1. A composite structural member comprising:
a) a first "U" shaped, longitudinally extending outer element;
b) a plurality of "U" shaped longitudinally extending inner elements;
c) a last "U" shaped, longitudinally extend-ing outer element;
wherein said first outer element, said plurality of inner elements and said last outer element, are superposed in two groups each forming a comb-like structure having its leg portions facing each other, both said groups being closely engaged together and firmly secured together.
a) a first "U" shaped, longitudinally extending outer element;
b) a plurality of "U" shaped longitudinally extending inner elements;
c) a last "U" shaped, longitudinally extend-ing outer element;
wherein said first outer element, said plurality of inner elements and said last outer element, are superposed in two groups each forming a comb-like structure having its leg portions facing each other, both said groups being closely engaged together and firmly secured together.
2. A composite structural member as claimed in Claim 1, wherein said first outer element is identical to said last outer element; and wherein an odd number of identical inner elements are provided.
3. A composite structural member comprising:
a) a plurality of inner longitudinally extending "U" shaped elements, each having a first leg and a second leg, wherein the distance between said first leg and said second leg is slightly larger than the total thickness of said first leg and second leg;
b) a first and second longitudinally extending "U" shaped outer element, each having a third leg and a fourth leg, wherein the distance between said third leg and said fourth leg is slightly larger than the thickness of said first leg and wherein the thickness of said fourth leg is equal to the thickness of said second leg; wherein a first said inner element having its legs point-ing in a direction opposite those of said first outer element is engaged around said fourth leg;
wherein the other inner elements are similarly engaged together and to said first inner element;
wherein said second outer element is similarly engaged to the outermost inner element; and wherein securing means firmly hold, said first outer element, said inner elements and said second outer element together.
a) a plurality of inner longitudinally extending "U" shaped elements, each having a first leg and a second leg, wherein the distance between said first leg and said second leg is slightly larger than the total thickness of said first leg and second leg;
b) a first and second longitudinally extending "U" shaped outer element, each having a third leg and a fourth leg, wherein the distance between said third leg and said fourth leg is slightly larger than the thickness of said first leg and wherein the thickness of said fourth leg is equal to the thickness of said second leg; wherein a first said inner element having its legs point-ing in a direction opposite those of said first outer element is engaged around said fourth leg;
wherein the other inner elements are similarly engaged together and to said first inner element;
wherein said second outer element is similarly engaged to the outermost inner element; and wherein securing means firmly hold, said first outer element, said inner elements and said second outer element together.
4. A composite structural member as claimed in claim 3, wherein an odd number of identical inner elements are used.
5. A composite structural member as claimed in claim 4, wherein said third leg extends to the outer surface of the closed portion of said first inner element.
6. A composite structural member as claimed in claims 3, 4 or 5, wherein said securing means are bolts.
7. A composite structural member as claimed in claims 3, 4 or 5, wherein said securing means are rivets.
8. A composite structural member as claimed in claims 3, 4 or 5, wherein said securing means is epoxy.
9. A method of producing a composite structural member comprising:
a) a plurality of inner "U" shaped elements, each having a first leg and a second leg wherein the distance between said first leg and said second leg is slightly larger than the total thickness of said first leg and second leg;
b) a first and second "U" shaped outer element each having a third leg and a fourth leg wherein the distance between said third leg and said fourth leg is slightly larger than the thickness of said second leg; said method comprising the foll-owing steps:
(i) preparing a rigid form having the exact shape which is required for the composite structural member;
(ii) placing said first outer element onto said form such that it conforms perfectly to said form;
(iii)placing a first of said inner elements with its legs pointing in a direction opposite to the legs of said first outer element, in engagement with said first outer element such that it conforms perfectly with it;
(iv) successively placing the remaining inner elements and said second outer element, with their legs pointing in a direction opposite to the legs of the previously placed inner element, in engagement with said previously placed inner element such that it conforms perfectly with it;
(v) rigidly securing together said first outer element, said inner elements and said second outer element.
a) a plurality of inner "U" shaped elements, each having a first leg and a second leg wherein the distance between said first leg and said second leg is slightly larger than the total thickness of said first leg and second leg;
b) a first and second "U" shaped outer element each having a third leg and a fourth leg wherein the distance between said third leg and said fourth leg is slightly larger than the thickness of said second leg; said method comprising the foll-owing steps:
(i) preparing a rigid form having the exact shape which is required for the composite structural member;
(ii) placing said first outer element onto said form such that it conforms perfectly to said form;
(iii)placing a first of said inner elements with its legs pointing in a direction opposite to the legs of said first outer element, in engagement with said first outer element such that it conforms perfectly with it;
(iv) successively placing the remaining inner elements and said second outer element, with their legs pointing in a direction opposite to the legs of the previously placed inner element, in engagement with said previously placed inner element such that it conforms perfectly with it;
(v) rigidly securing together said first outer element, said inner elements and said second outer element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000364143A CA1152636A (en) | 1980-11-06 | 1980-11-06 | Composite structural member for antenna |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000364143A CA1152636A (en) | 1980-11-06 | 1980-11-06 | Composite structural member for antenna |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1152636A true CA1152636A (en) | 1983-08-23 |
Family
ID=4118368
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000364143A Expired CA1152636A (en) | 1980-11-06 | 1980-11-06 | Composite structural member for antenna |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1152636A (en) |
-
1980
- 1980-11-06 CA CA000364143A patent/CA1152636A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |