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WO1982000545A1 - Reflecteur parabolique et son procede de fabrication - Google Patents

Reflecteur parabolique et son procede de fabrication Download PDF

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Publication number
WO1982000545A1
WO1982000545A1 PCT/US1981/000997 US8100997W WO8200545A1 WO 1982000545 A1 WO1982000545 A1 WO 1982000545A1 US 8100997 W US8100997 W US 8100997W WO 8200545 A1 WO8200545 A1 WO 8200545A1
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WO
WIPO (PCT)
Prior art keywords
spokes
reflector
curvature
radial
dish
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.)
Ceased
Application number
PCT/US1981/000997
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English (en)
Inventor
R Luly
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to AU74525/81A priority Critical patent/AU7452581A/en
Publication of WO1982000545A1 publication Critical patent/WO1982000545A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/12—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave
    • H01Q19/13—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave the primary radiating source being a single radiating element, e.g. a dipole, a slot, a waveguide termination
    • H01Q19/134—Rear-feeds; Splash plate feeds
    • 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
    • H01Q15/16—Reflecting surfaces; Equivalent structures curved in two dimensions, e.g. paraboloidal
    • H01Q15/161—Collapsible reflectors

Definitions

  • This invention relates generally to methods for constructing dished reflector surfaces and to structures achieved thereby, and more particularly concerns a light- weight, foldable parabolic reflector and a radio frequency antenna assembly incorporating the foldable reflector.
  • the method and structure of the invention also pertain to the field of solar energy collectors and parti- cularly to foldable lightweight, portable solar energy col- lectors.
  • the deployable solar cooker disclosed in this paper does not teach the present invention in that it relies only on the curvature of the pre-formed dish of reflecting fabric. As described, the radial spokes are of spring metal and "flex only as forced by the fabric.” Man's Greatest Adventure by Laurence Allen, 1974, Library of Congress Card No. 74-17235, includes various photographs showing deployable antennas used on the lunar space mission. In particular, a small portable folded S-band dish antenna is shown at page 46. The S-band antenna photographs do not teach a curved dish structure in coopera- tive relationship with an independently stressed spoke framework. The tripod-mounted S-band antenna is considerably smaller than the dishes contemplated by the applicant's invention. The structure shown in the reference, if en- lar ed and de lo ed in a 1G ravitational field, would not 1 be sufficiently rigid to define a usable self-supporting
  • the perimeter wire of the reference serves as a peripheral 1 support means for attaching the wire mesh of the reflector 2 to the rib skeleton.
  • the dish * be made portable by removing the mesh sheet,- and disasse - 5 bling the rib structure.
  • the mesh is at- 6 tached by folding the edges over the wire perimeter.
  • the 7 ribs lie over the frontal reflecting surface of the mesh 8 sheet, whereas in applicant's antenna the reflector surface 9 is unbroken and the radial spokes are attached to the rear of the pliable reflector dish.
  • the applicant is not aware of folding dish re- flectors in the 9- to 16-foot diameter range for use on the earth's surface, that is, in a l ' G gravitational field.
  • the Folding Dish Reflector improves over the prior art by providing a low-cost, lightweight foldable reflec- tor assembly of precise curvature which is repeatable through many folding-deployment cycles of the reflector and which can be made of relatively low f/d ratio. Cost and complexity is kept to a minimum by providing normally straight radial spokes for supporting the pliable re- fleeting surface, instead of the costly pre-formed curved radial supports of the prior art.
  • the preferred embodiment of the invention is a foldable reflector having a pliable substantially inelas- tic dish of pre-formed curvature and an independently stressed radial framework comprising a plurality of radial spokes of tapered cross section and a perimeter cable connecting the tips of the poles or spokes .
  • This preferred embodiment is illustrated in Figures 1-9, and the method of making the same is shown in Figures 10-17. It is contemplated, however, that three alternate embodiments are possible within the scope of this invention, and these are: i) A foldable reflector as in the preferred embodiment but omitting the constricted perimeter cable.
  • the tapered spokes are thus curved only by the necessity to conform to the curvature of the pre-formed pliable dish * In this embodiment, the use of radial spokes -6-
  • the 3 radial members which preferably are of tapering cress 4 section are then stressed by a perimeter cable, to 5 obtain a desired curvature.
  • the stretched reflect- 6 ing fabric resiliently contracts to take up the re- 7 sultant slack and thus defines a dished reflector -7-
  • This 13 combination is particularly useful in folding dish 14 reflectors, but is not limited thereto, 15 ii) The use of rods of tapered cross section as the . 16 radial elements in the stressed framework.
  • the 17 tapered rods enable the construction of deeper 18 stressed dish reflectors than has been possible 19 until now to obtain a lower f/d ratio.
  • the foldable spoke framework comprises a
  • a cable or equi ⁇ 5 valent means is threaded through the tips of the spokes to 6 define a perimeter calculated to have a diameter less 7 than that of the fully deployed radial spokes.
  • a pliable dish of reflecting sheet material is
  • the beam is flexed by application of a perpendicular force
  • the novel reflector structure enables the construct tion of a folding reflector antenna which can be quickly and easily deployed and mounted on a tripod or other simple support structure, and can be easily and precisely aimed.
  • the preferred reflector antenna assembly is a Casse- grain arrangement with an axial wave guide, a large primary reflector mounted to and supported by the wave guide for reflecting electromagnetic radiation towards the front of the wave guide and a smaller secondary or sub-reflector mounted at the front of the wave guide for reflecting the radiation into the wave guide.
  • Such construction for a relatively large, i.e., 10- to 15-foot diameter, earthbound folding antenna is /// -10-
  • the axial support also serves as a
  • a low-noise amplifier housing may be attached,
  • the low noise amplifier and any 2 desired frequency converters can be mounted directly 3 within the rear end of the wave guide without necessity 4 of any additional housing or transition.
  • This technique 5 is useful at frequency ranges which call for a wave 6 guide diameter sufficiently large to accommodate the 7 amplifier's electronics, and results in considerable cost 8 savings.
  • the weight of the amplifier counter-balances 9 tne weight of the forward portion of the wave guide and 0 the secondary reflector attached thereto, the entire 1 unitary assembly being supported at the wave guide, pre- 2 ferably behind the main reflector assembly.
  • the basic antenna 4 structure described herein i.e., a large folding dish 5 reflector entirely supported by a rigid axial tube, can 6 also serve as a solar collector dish.
  • the 7 sub-reflector may be removed and fluid circulated through 8 the axial tube for heatin at the dish focus.
  • the reflector assembly of this invention is pre- ferably constructed by cutting a number of trapezoidal panels of pliable reflecting material with the divergent sides of the panels being cut along a curve calculated such that the panels may be attached one to another along the curved sides to form a complete circle of such panels, and when so attached, the panels will define a pliable centrally apertured dished surface of predetermined curvature.
  • the panels are then attached as by sewing along the curved sides to complete such a dished reflect- ing surface, and radial folds are formed, as by sewing, preferably on the rear concave surface of the pliable dish reflector.
  • the radial folds may be of tubular nature and dimensioned for snugly receiving within each fold one tapered radial spoke.
  • a normally straight resiliently flexible spoke of tapered cross section is inserted into each of the folds of the unsupported pliable reflector so that the thicker butt end of each spoke extends towards the center of the dished structure.
  • the spokes are in- serted one by one into the dish folds and are fastened to the dish as by screwing at the two ends of the spokes or other suitable means.
  • the spokes are then pivotally mounted at their butt ends to a central hub with the pliable reflecting material loosely supported or folded between the spokes.
  • a cable is threaded through openings formed in the tip of each radial spoke to form a perimeter interconnecting .the spoke tips.
  • the cable is slidable through the tip openings and the length of the cable is constricted to define a perimeter having a predetermined diameter less than the unstressed radially extended diameter of the radial spokes.
  • the cable thus restrains the spokes against full radial deployment and causes the spokes to curve inwardly and retains the spokes in the aforedescribed radially ex- tended stressed condition in cooperation with the pliable dish of reflecting material.
  • the pliable dished surface may then be deployed and stretched to smoothly conform to the predetermined curvature by simultaneously pivoting the spokes to a radially extended position, thereby stressing the tapered spokes against the restraint imposed by the cable perimeter, which thus conform to the predetermined dish curvature within the folds.
  • the tapered spokes are retained in a stressed radially extended position during use of the reflector and are released to a generally axial unstressed folded position for transportation or storage of the reflector assembly.
  • the perimeter cable also provides a means for adjusting to a fine degree the final curvature of the dish , in the deployed position by making adjustments to the peri meter length defined by this cable.
  • the cable serves the further purpose of preventi deterioration of the reflector's precise curvature from eventual stretching of the reflecting sheet material and a resultant flattening of the pre-formed pliable dish de- fined thereby.
  • a cable or equivalent means is threaded through openings formed in the tips of the spokes to define a perimeter.
  • the cable is not secured to the tips and is free to slide through the openings therein.
  • the cable perimeter is then constricted to a reduced diameter so as to stress the spokes to a desired curvature.
  • the elastic sheet material contracts as neces ⁇ sary from its initially stretched condition to conform to the curvature of the radial spokes, thereby defining a dished reflector surface of a desired curvature, /// /// -I -
  • Figure 1 is a rear perspective view of a portable parabolic dish antenna incorporating the folding reflector of this invention
  • Figure 2 is a schematic cross section showing the optics of the antenna of Figure 1
  • Figure 3 is an axially broken cross section taken along line 2—2 of Figure 1 showing the pivotal mounting of the main reflector spokes to the axial wave guide, the secon dary reflector, and the amplifier housing mounted to the rear end of the wave guide
  • Figure 4 shows the detachable coupling of the am- plifier transition to the rear end of the wave guide
  • Figure 5 is a cross section taken along line 3—3 of Figure 3 showing the main reflector assembly in three radially broken apart sections, the innermost section showin the mounting of the radial spokes to the central hub, the intermediate section showing the connection of the pivot levers to the radial spokes, and the outermost section showi the perimeter cable threaded through the spoke tips;
  • Figure 6 is a partial perspective view of the pivotal mounting of the radial spokes and pivot levers to their respective hubs on the axial wave guide together with the pivot lever locking assembly;
  • Figure 7 is an exploded perspective view of the preferred central hub assembly and mounting of the radial 1
  • Figure 8 is a partial perspective view in two
  • Figure 10 shows a number of adjacent reflecting 0 panels prior to attachment along the curved divergent side
  • Figure 12 shows the preferred manner of inserting 1° " individual radial spokes into the folds of the pliable
  • Figure 16 illustrates the threading of a cable 5 through the spoke tips to define a perimeter; 6 /// .
  • Figure 17 is an enlarged view of a turnbuckle used to adjust " the cable perimeter of the folding reflec- tor dish;
  • Figure 18 is an initial step in an alternate method of making a dished reflector wherein radial spokes have been affixed to a central support;
  • Figure 19 shows an intermediate step in the alternate method wherein stretched elastic panels .have been attached to the radial spokes to define a planar disc;
  • Figure 20 shows the completed dished reflector wherein the radial spokes are stressed to a desired curvature by a constricted perimeter cable.
  • a re- 1 DC antenna 10 comprises a main reflector 12 in the 2 form of a parabolic dish supported on an axial metallic 3 tube 14 which is both the main support for the various 4 components of the antenna system as well as being a wave 5 guide for transmission of electromagnetic waves from the 6 ' focal point to a receiver amplifier 16 mounted to the rear end of the wave guide 14.
  • a smaller secondary reflec- tor 18 is shown as a dotted disc mounted to the front end of the wave guide 14 and supported entirely thereby.
  • the entire antenna assembly is supported by a tripod 20 pre- ferably attached only to the wave guide 14 at a point intermediate the main reflector 12 and the amplifier 16.
  • Figure 2 shows the optics of the receiving antenna 10, where incident rays 22 and 22' are reflected by the parabolic reflector 12 towards the front of the axial wave guide 14 -where the rays are again reflected by the secondary reflector 18 towards the open front end 24 of the wave uide 14.
  • the electromagnetic wave is transmitted down the length of the wave guide 14 towards the rear end 26 of the wave guide.
  • the main reflector 12 of Figure 1 is seen to consist of a plurality of evenly spaced radial spokes 30 mounted to the wave guide 14, and wedge shaped panels 32 of a pliable substantially inelastic reflecting material sup- ported between each adjacent pair of radial spokes 30 to define a dished reflector 12 with a concave surface facing the forward end 24 of the wave guide 14.
  • the reflecting surface is formed by attaching side-by-side trapezoidal panels 32, the long, divergent sides of which are cut along a curve calculated to yield a parabolic curve along the line of juncture 31 of adjacent panels 32.
  • the individual spokes are encased in tubular - folds 33 extending radially on the rear surface of the re- flector dish along each line of juncture.31.
  • the presently preferred spokes 30 are tapered normally straight resilienrly flexible rods of circular cross section and hollow construction.
  • a parabolic reflector ten feet in diameter is constructed with hollow fiberglass rods five feet in length and having wall thickness of one sixteenth of an inch (1/16"), and tapering from a maximum internal diameter of one half of inch (1/2") at the butt end to an internal diameter of five sixteenths of an inch (5/16") at the tip.
  • a focal length of approximately five feet can be obtained, yielding a 0.5 f/d ratio. This is a lower i
  • the opti taper of the rods will vary with the desired diameter and f/d ratio of the finished dish reflector, i.e., the length and desired curvature of the spokes.
  • the tapering cross section creates a gradient in the stiffness of the rod along its length. By varying this gradient different curvatures may be obtained.
  • One simple way of determining whether a given rod taper is suitable fo use in a reflector of given f/d ratio is to load the rod to the same extent that it would be in the reflector, and cast shadow of the stressed rod onto a surface on which has been drawn the desired curve.
  • a twelve-foot dish can be constructed with six-f poles having the same rate of taper as the five-foot poles. The length of the poles is extended to terminate in.an insi diameter of five thirty-seconds of an inch (5/32") .
  • a spherical dish reflector can be obtained by making the spokes more flexible towards the tip end to get a greater curvature than would be necessary in a parabolic reflector. The pliable dish would also be made as a spheric segment.
  • the wave guide 14 is seen to consist of a straight metallic tube having a front end 24 and a rear end 26 and open at both ends.
  • the tube 14 is of a suitable metallic substance such as aluminum or a steel alloy having sufficient strength to provide adequate r v id su r f 2 as well as the secondary reflector 18 and amplifier housing 16 mounted at the front and rear ends respectively.
  • the internal diameter of the tube 14 is chosen such that it serves as a wave guide for electromagnetic radiation at a desired frequency band.
  • a pair of radially opposite spokes 30 are shown mounted at their radially inner butt ends 34 to a central i hub structure 36.
  • the hub 36 is in turn affixed to the wave guide 14 as by welding to a collar 37 or by any other suitable means.
  • a second hub structure 38 of somewhat larger diameter is mounted for sliding movement along the wave guide 14 rearwardly of the first hub 36.
  • a short collar 39 is affixed to the hub 38 to keep it from wobbling.
  • a pivot lever or linkage rod 40 connects the second hub 38 to an intermediate point 42 along each of the radial spokes 30.
  • the levers 40 are connected for pivotal movement by pin 44 to a D-clip 46 secured at point 42 to the radial spokes 30.
  • Each one of the radial spokes 30 and the levers 40 are mounted for pivotal movement at their radially inner ends to the respective central hubs,. as illustrated in Figures 5 and 6.
  • the sliding hub 38 i'S of enlarged diameter to thereby space the levers radially outwardly about the spokes in the folded position.
  • the presently preferred structure of the central hubs 36 and 38 is best understood in the exploded view of Figure 7.
  • a first disc 48 has evenly spaced radial slots so formed therein and is centrally perforated for receiving -21-
  • a second disc 52 is similarly centrally
  • annular space or groove 61 (best seen in Figure 6) is
  • a mounting member 62 of elongated planar configuration is 3 provided for each radial spoke and has formed at one end 4 a hole 63 through which passes the annular retaining ring 5 60, each mounting member 62 being retained by the ring 60 6 within one aligned pair of grooves 50, 54 of the spaced 7 discs 48 and 52.
  • each mounting member 62 is re- 2 ceived within the hollow interior of one radial spoke 30 3 and secured therein. In this fashion the spokes 30 are 4 mounted to the hub assembly for pivotal movement between a 5 generally axial folded position and a generally radial or 6 extended position.
  • the discs 48 and 52 are affixed to the 7 spacer 56 by suitable means such as riveting at holes 53.
  • each hub is provided with a short collar coaxial
  • the simultaneous pivotal movement - of the radial spokes 30 is effected by means of levers or linkage rods 40 which are preferably " straight elongated members formed of sheet metal such as aluminum or steel, and are hingedly attached at one end to the radial spokes and pivotally connected at the opposite or rear end to a.
  • hub 38 of construction similar to that of hub 36, as des- cribed above. Hub 38, however, is mounted to the axial support or wave guide 14 for sliding movement along the axial support rearwardly of the fixed spoke hub 36.
  • the pivotal movement of the radial spokes between the folded and the extended positions is thus effected by sliding movement of the sliding hub 38, the movement of the sliding hub 38 being transmitted to the pivoting spokes 30 by the levers 40.
  • the linkage rods or levers 40 are connected to the radial spokes 30 for pivotal movement as best shown in Figure 8.
  • the forward or radially outer end 41 of the lever 40 is hingedly attached at pivot pin 44 to a ⁇ -clip 46 se- cured to the radial spoke 30.
  • the position of the U-clip will determine the amount of leverage obtained through the linkage rods 40. That is, the greater the radial displace- ment of the clip 46, the greater the leverage that will be obtained to .deploy the reflector. For a reflector of ten to fifteen feet in diameter it has been found adequate to place the clips 46 within a range of ten to twenty inches from the- butt end of the spoke 30, the preferred point being fourteen 1 clip 46 extends from the spoke 30 through an opening 47
  • the radial spokes are 4 stressed to a desired curvature, independently from the dish curvature, by a cable 66 threaded through the tips of the spokes to form a perimeter of reduced diameter, that is, a diameter less than the unstressed diameter of the fully extended radial spokes 30.
  • the spokes are curved to the desired shape by the cable and little, if any, reliance is placed on the shape of the dish to obtain a given spoke curvature.
  • both the stressed spokes and the dish must be formed initially to closely similar curvatures in order to obtain the necessary cooperation between the two individually curved elements.
  • the cable 66 shown in Figure 5 may be made of steel and is threaded through openings or eyelets 68 formed in the tips 35 of the radial spokes 30.
  • openings or eyelets 68 formed in the tips 35 of the radial spokes 30.
  • a pair of over-the-center cam locks 70 and 70 are affixed to the axial support or wave guide 14 rearwardly of the sliding hub 38.
  • Hub 38 is" provided with a pair of rear- wardly extending hook members 72 and 72' which are pre- -25-
  • Each over-the-center cam lock 70, 70' has a r
  • the over-the-center cam lock pair thus 0 serves the dual function of leveraging the manual force 1 applied to the lever 76 to facilitate the full deployment 2 of the dished reflector against resistance of the spokes, 3 as well as serving to lock and retain the hub 38 at its 4 rearmost position to thereby retain the reflector in 5 stressed fully deployed position.
  • the hub 38 is released 6 for folding the reflector by pivoting the levers 76 to a 7 forward position as shown in phantom line in Figure 3, and 8 then disengaging the hooks 72 from the retainers 74.
  • the reflector can be partially deployed by manually unfold- 0 ing the dish-spoke assembly as represented by movement of 1 the sliding hub 38 in Figure 3 from the phantom position A 2 to the phantom position B.
  • the over-the-center cams are engaged with the hooks 72, 72' for movement of the hub 38 to the solid-line posi- tion C, this rearmost position of the hub 38 corresponding to full deployment of the reflector dish.
  • the rearmost posi- tion of the sliding hub 38 is adjustable by means of the threaded hooks 72, 72', which position in turn determines the stress or rearward force applied to the spokes at points 42 by the levers 40.
  • the curvature of the central portion of the dish 12 is thus adjustable by threading the two hooks 72, 72' into and out of the corresponding threaded bores in the sliding hub 38.
  • the periphery of the reflector dish can be ad- justed for optimum curvature by appropriate adjustment of the cable perimeter 66, as has been explained.
  • the reflector of this invention is thus provided with means for independently adjusting the curvature of the peripheral, radially outer area of the reflector disc, and the central, radially inner area of the reflector.
  • the curvature of the dish can be checked against a template and corrections made as necessary.
  • the secondary reflector 18 may be affixed to the front end 24 of the wave guide 14 by means of a sleeve 19 which fits at its rear end over the open front end 24 of the wave guide and is securely affixed to the center of the secondary reflector disc 18 at its opposite end.
  • the cylinder 19 closes the front end of the wave guide against entry of foreign matter, debris and moisture, but is made of a material transparent to electromagnetic radiation, such as plastic or plexiglass.
  • the radiation focused by the main reflector dish 12 is reflected without hindrance into the front end of the wave guide 14 by the secondary reflector ig.
  • the cylinder may be replaced by a plug 1
  • the housing 16 for a low noise amplifier can
  • the wave guide tube 14 can be made of internal
  • a first disc 200 defines a plurality of peri- pheral radial slots 202 and is centrally apertured for receiving the axial support tube or wave guide 14.
  • a second disc 204 is similarly centrally aper- tured and is provided with a number of radial fingers 206.
  • Each radial finger is provided with a tangentially project- ing pin 208 which extends in a clockwise direction into the space between adjacent radial fingers 206 but does not fully bridge this space, so as to form a gap 210 between the end of the pin and adjacent radial finger.
  • the mounting members 62 are disposed radially in the slots 202, the second disc 204 is brought into adjacent relationship with the first disc 200 with each of the mounting members in register with a gap -210 of the second disc.
  • the second disc 204 is then rotated clockwise with respect to the first disc 200 such that the pins 210 simultaneously engage the hole .63 formed in the radially inner end of each mounting member 62.
  • the two discs are then secured to one another by means of one or more rivets 212 fitting into aligned holes 214.
  • the mounting members 62 are thus free to pivot
  • a preferred material for the radial spokes is fiber glass, the rods being made by known processes such as by winding resin impregnated fiber glass cloth on a tapered core, the core being withdrawn after hardening of the resin.
  • the invention is not restricted to hollow spokes, and other materials may be found equally suitable, such as carbon, graphite, metal and others. Fiber glass is preferred in that it is a low cost, readily available material of great resiliency, largely impervious to weather, and very durable.
  • the pliable reflecting material for the panels 32 may be metallized mylar which provides a pliable, non- elastic base and a thin film of metal as the necessary re- fleeting surface for reflecting electromagnetic radiation, and if finished to a high polish, is also suitable for reflecting solar radiation.
  • the reflecting material may be an open mesh, either -29-
  • resulting joint line will be a paraboloidal curve or an 0 arc of a circle, depending on the desired curvature of t 1 assembled reflector dish.
  • a number of panels 90 are laid 2 side by side in this manner to form a complete circle, t 3 form a pliable dish structure approximating a paraboloid 4 of revolution or a spherical segment. It is understood 5 that at this point the dish is not in a stretched condit 6 rather it is a loosely folded structure of pliable sheet 7 material or fabric.
  • the dish 95 has no rigid support at 8 this stage of assembly.
  • a plurality of folds 97 which may be formed ' co currently with the joining of the individual panels 90, formed in the rear or convex surface 96 of the dish 95 a shown in Figures 11 and 12.
  • the folds 97 are of tubular structure so as to snugly receive within each tubular fol one of the tapering radial spokes 98.
  • the insertion of t spokes 98 is illustrated in Figure 12 resulting in a loos generally conical structure wherein the dish 95 is provid with radial support but the individual panels 90 supporte 1 After each of the tubular folds 97 has received
  • the hub 99 is
  • each mounting member being adapted to fit into
  • the axial support 100 is in-
  • each of the radial spokes 18 is connected at an intermediate point 102 to a slidable 19 hub assembly 104 by means of a lever or linkage rod 105 as 20 in Figure 14.
  • Each of the linkage rods 105 is also pivotal- ly mounted to the hub 104 and is further pivotally mounted
  • the levers 105 operate to 26 exert a pulling force on the radial spokes 98 at points 102 27 thereof urging the spokes to a fully extended racial posi ⁇ 1
  • this perimeter binding includes a cable such as a steel cable 108 in Figures 16 and 17, which is passed through openings or eyelets 110 formed in the tips 112 of the radial spokes 98.
  • the pliable dish 95 in cooperation with the peri- meter cable 108, operates to restrain the spokes 98 against such complete radial deployment, thereby stressing the radial spokes 98 to a curvature in compliance with the curvature of the pre-formed dish 95 since the spokes 98 are attached along their full length to the rear con- vex surface 96 of the dish 95.
  • the dish 95 is made of a substantially inelastic material such as mylar or an aluminized polyester cloth on the concave or interior side 93 of the dish.
  • the rear convex side 96 of the dish may be a backing of polyester, dacron or nylon cloth.
  • the fabric may be reinforced against stretching by stitching a square pattern of nylon threads placed 1/4 of an inch apart and laminating the nylon threads by compression onto the reflector fabric. Other means of reinforcing the fabric may be resorted to.
  • a turnbuckle 115 completes the cable perimeter by joining the ends of the cable 108 such that the length -32-
  • spokes 98 may be increased beyond the curvature imposed by
  • the dish 95 is substantially inelastic in order to retain
  • the cable 108 also serves as a first fabric and synthetic sheet materials.
  • the cable 108 also serves as a second fabric and synthetic sheet materials.
  • a perimeter cable 126 is threaded through openings or 7 eyelets 130 provided in the tips 128 of the spokes 120.
  • the -3J - perimeter cable is then constricted to a reduced diameter which is less than the diameter of the unstressed radiall deployed spokes of; Figure 18.
  • This constricted perimeter cable 126 stresses the spokes 120 to a curvature which is determined by the diameter of the constricted cable ; perimeter 126.
  • the panels 124 resiliently absorb the - resulting slack due to their initially stretch condition. • _ The result is a dished structure as shown in Figure 20.
  • the cable 126 is threaded through the eyelets or openings 130 in the tips 128 for sliding movement therethrough.
  • a turnbuckle may be used to connect the two ends 132 and 134 in Figure.19, the turnbuckle providing a means for fine adjustment of the cable perimeter length, which in turn serves to adjust the curvature of the dish reflec- tor 140.
  • the reflector dish struc- tures produced by either the preferred or alternate methods can be of the folding type if the spokes are mounted for pivotal movement and a sliding hub and linkage rods are provided.

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  • Electromagnetism (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

Une antenne reflectrice portative, legere, pliante, de reception de signaux de micro-ondes comprend un tube axial de guide d'ondes (14) qui constitue l'organe de support principal de la structure de l'antenne, un reflecteur parabolique de dix a quinze pieds de diametre (12) monte sur le guide d'ondes et un sous-reflecteur (18) supporte a l'extremite avant du guide d'ondes. Un amplificateur de faible bruit (16) peut etre monte sur l'extremite arriere du guide d'ondes pour amplifier les signaux recus. Le reflecteur parabolique pliant consiste en un reflecteur parabolique preforme en materiau pliable (32) supporte par une structure radiale consistant en rayons droits elastiquement flexibles (30) de section conique. Les rayons pivotent par un systeme de levier (40) entre une position radiale deployee. Les rayons en position normale droite sont sollicites lors du deploiement par un cable perimetrique pour prendre la courbure du reflecteur parabolique pliable de telle sorte que les rayons et le reflecteur parabolique soient courbes independamment l'un de l'autre et corrigent les deviations de la courbure desiree l'un en fonction de l'autre pour ainsi obtenir une courbure du reflecteur parabolique pouvant se repeter de maniere precise a chacun des nombreux cycles de pliage-deploiement. Un procede d'assemblage du reflecteur pliant, ainsi que d'autres modes de realisation de reflecteur leger, incurve, sont decrits.
PCT/US1981/000997 1980-07-28 1981-07-28 Reflecteur parabolique et son procede de fabrication Ceased WO1982000545A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU74525/81A AU7452581A (en) 1980-07-28 1981-07-28 Parabolic reflector and method of making the same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
MX18333380A MX148406A (es) 1980-07-28 1980-07-28 Mejoras en antena satelite
MX183333800728 1980-07-28

Publications (1)

Publication Number Publication Date
WO1982000545A1 true WO1982000545A1 (fr) 1982-02-18

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Application Number Title Priority Date Filing Date
PCT/US1981/000997 Ceased WO1982000545A1 (fr) 1980-07-28 1981-07-28 Reflecteur parabolique et son procede de fabrication

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EP (1) EP0056406A1 (fr)
MX (1) MX148406A (fr)
WO (1) WO1982000545A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0244969A3 (fr) * 1986-05-02 1989-03-08 Borg-Warner Chemicals Europe BV Antenne pour réception directe de satellite
EP0452077A1 (fr) * 1990-04-09 1991-10-16 Marconi Electronic Devices Limited Arrangement d'antenne
WO2012146426A1 (fr) * 2011-04-27 2012-11-01 Bron Elektronik Ag Réflecteur pliant
US8384614B2 (en) 2010-09-30 2013-02-26 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Deployable wireless Fresnel lens
CN108832306A (zh) * 2018-06-13 2018-11-16 中国科学院国家天文台 一种fast反射面中心孔柔性封堵结构

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3286270A (en) * 1964-07-01 1966-11-15 Gen Electric Collapsible parasol-like reflector utilizing flexible honeycomb shell
US3635547A (en) * 1969-12-08 1972-01-18 Westinghouse Electric Corp Reflector construction
US4201991A (en) * 1978-03-16 1980-05-06 Paraframe, Inc. Antenna structure assembled from separable parts
US4249184A (en) * 1978-03-16 1981-02-03 Vines James K Antenna arm and method for making the arm

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3286270A (en) * 1964-07-01 1966-11-15 Gen Electric Collapsible parasol-like reflector utilizing flexible honeycomb shell
US3635547A (en) * 1969-12-08 1972-01-18 Westinghouse Electric Corp Reflector construction
US4201991A (en) * 1978-03-16 1980-05-06 Paraframe, Inc. Antenna structure assembled from separable parts
US4249184A (en) * 1978-03-16 1981-02-03 Vines James K Antenna arm and method for making the arm

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0244969A3 (fr) * 1986-05-02 1989-03-08 Borg-Warner Chemicals Europe BV Antenne pour réception directe de satellite
EP0452077A1 (fr) * 1990-04-09 1991-10-16 Marconi Electronic Devices Limited Arrangement d'antenne
WO1991015880A1 (fr) * 1990-04-09 1991-10-17 Marconi Electronic Devices Limited Antenne
GB2245103A (en) * 1990-04-09 1991-12-18 Marconi Electronic Devices Antenna with reflectors supported by a waveguide
US8384614B2 (en) 2010-09-30 2013-02-26 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Deployable wireless Fresnel lens
WO2012146426A1 (fr) * 2011-04-27 2012-11-01 Bron Elektronik Ag Réflecteur pliant
US9267662B2 (en) 2011-04-27 2016-02-23 Bron Elektronik Ag Folding reflector
CN108832306A (zh) * 2018-06-13 2018-11-16 中国科学院国家天文台 一种fast反射面中心孔柔性封堵结构
CN108832306B (zh) * 2018-06-13 2023-11-03 中国科学院国家天文台 一种fast反射面中心孔柔性封堵结构

Also Published As

Publication number Publication date
MX148406A (es) 1983-04-18
EP0056406A1 (fr) 1982-07-28

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