US2898592A - Reflector structures for antennas - Google Patents

Description

Aug. 4, 1959 Filed April 9, 1954 A. F. CARTHAY REFLECTOR STRUCTURES FOR ANTENNAS 4 Sheets-Sheet 1 H- F Cari/50y INVENTOR.

Arr-n A ug. 4, 1959 2,898,592

REFLECTOR STRUCTURES FOR ANTENNAS Filed April 9, 3954 4 Sheets-Sheet 2 p 19 v I T 36 102 9 6 I 1 g 72' 61 5 i A l 6 1 72' I 72 5I I [/j J 17 46 5 '4 55 a; b 88 a;

I N V E NTOR.

Aug. 4, 1959 A. F. CARTHAY REFLECTOR STRUCTURES FOR ANTENNAS Filed April 9, 3954 4 Sheets-Sheet 3 v INVENTOR.

i 1 CarUna Aug. 4; 1959 A. F. CARTHAY REFLECTOR STRUCTURES FOR ANTENNAS 4 Sheets-Sheet 4 'Filed April 9. 1954 l \IIY iii '1! 9 1 M w g g/ .N

United States Patent REFLECTOR STRUCTURES non ANTENNAS Alexander F.- Carthay, Kerhonkson, N.Y., assignor, by mesne assignments, to Channel Master Corporation Application April 9, 1954, Serial No.. 422,173.

7 Claims. (Cl. 343-817) The present invention concerns improvements in an,-

roof tops, installers must work in precarious and dangerous positions. It is therefore important to provide antennas which can readily be assembled and handled during erection, with a. minimum: of tools: and. manual operations, so as to minimize. the dangers of such installations.

In addition, from the view point of the. manufacturer;

is is important that the various: component partshe Sim:- ply fabricated and assembled, at the; factory, to; provide 2 of. the L0 tri-pole antenna incorporating structural features according to the present invention.

As shown in Fig. 1, a long (low-band) folded dipole 5.1 is mounted substantially in a horizontal plane above and" below which are the short (high-band) folded dipoles" 52 and 53, equally spaced, therefrom, and also in respective horizontal planes. The long dipole 51 is spaced closely and parallel to the short dipoles 52, 53, their electrical characteristics and interrelationship being describedin-said Lo application.

All of the dipoles 51-, 52, 53 are mounted on a vertical post 91 which in turn is secured to a horizontal cross arm 54; which is supported from a vertical mast55, usually mounted on the house or building structure. The cross arm 54 also supports the reflector screen 56, shown in this instance as a plurality of parallel horizontal rods 57 with a pair of joined vertical rods .58. This structure is described more in detail below. A transmission line harness 46 interconnects the dipoles 51, 52, 53 to a terminal block from which the down-lead transmission line extends to the receiver.

The structural features of this antenna, which provide advantages infabrication, in structural strength and stability, and in case of: assembly, are shown in. Figs. 2-7.

As. will beseen, the. antenna structure as a whole is made collapsible and foldable, so that it may be readily packed for shipment and then, in a simple manner,

anantenna which can be compactlyand simply packaged and yet quickly unpacked and. assembled at; the; in

stall'ation. spot, while still providing; efiicientelcctrical op.- eration and rigidity in the mounted condition;

These and other advantages. and objicctsof the-present invention will be more readily understoo from consideration. of the following description; taken; in conjunction with. the appended drawings, in which Fig. 1- is a perspective assembly view of one form of the present invention.

Fig. 2 is a fragmentary front view: ofithe. structure of Fig. 11.

Fig. 3. is a fragmentary bottom view of the SlIiuGwIe of; Figs. 1 and 2, partly in section, viewed along line 17--1-7- of Fig. 2.

Fig. 4 is a fragmentary top. view of the. structure of Figs. l-3, viewed along line 19-19 of Fig. 2;

Fig. 5 is a fragmentary elevation view, in, section, of a dipole clamping means, viewed along line 20.-.20 of'Fig. 2:-

Fig; 6. is a fragme ary; elevation vievw, p rtly in secerected with a. minimum of eflort and the use of a mini? mum number of tools. The long dipole 51 ismade. of conductive tubing, such. as aluminum tubing, and as seen most clearly in Fig. 3-,. may be formed of a single long red 7.1- having its. ends bent andfiattened as at 72, in as sociation with a. pair of shorter rods 73, each having a similar bent and flattened end 74 securedto a respective end 752 as by riveting. at 7.55. The other ends of the shorter rods: 73 are flattened as at 7.6, and are riveted or otherwise. suitably fixed to an. insulating block 77, such asof; Bakelite, Micarta, or the like. The coupling harness indicated generally at 46 has three transmission linev sec:- tion' branches, one branch 79 having its respective termi'nals joined to. the flattened ends 76 of the rods 73, as by the: same rivets which secure rods 73 to block 77.

The; other terminals of this harness branch 79 are riveted or otherwise secured to the terminals 81- of a terminal block 82 to which are also joined the other harness branches. 83. and 84, leading to the smaller dipoles tion, of another dipole. clhmp ngjmeans iewed along line 21-21 of Fig. 2;

Fig; 7. is a perspective view of a. two-bay arrangement oftthelstructureof Fig. 1.,

Fig. 8 is anenlargedperspective view of aligned ridges and" grooves formedin the flattened ends; ofi vertical. rods 58 tomaintain their alignment seated: on. one.-another..

The present invention is illustrated; particularly as. applied to a tri-pole or triple dipole arrangement for wide-band television reception, whose principles are described in the forementioned Lo patent application, although in its broader aspects the present invention is not limited thereto. As disclosed in said Lo application, the tripole antenna has one long or low-band dipole above and below which are respective. 0 1. 5. of a pair of short or high-band dipoles, interconnected by a transmission line harness having threetransmission line. sections coupled. to a. pair of conunonterminals, the antenna having also a, vertical reflector screen. spaced from the. dipole array. Fig; 1.: is: a; perspective view of an. embodiment 52 and. 53.

The smaller dipoles 52 and 53, are formed similarly to thelong dipole 51, each having a long uninterrupted side 86 and an interrupted. side parallel thereto having arms: 87 with flattened ends, 88 joined to a respective insulating block 89 and 9 0. Where desired, each of these folded. dipoles, 51, 52 and 53, can be made of a single .pieccof tubing bent into a fiat elongated loop with one uninterrupted side and the other side interrupted at its center to form two adjacent ends mounted on terminal blocks such as 77,89 and 90, as shown for small dipole 52. in Fig. 4, or they may be made of separate rods joined at their ends. as described relative to dipole 51. and shown in Fig. 3.

For the purpose of. rigidly mounting the dipole asscrn:

bly from the cross arm 54, a vertical supporting post 91 is provided which has a bayonet socket or other suitable clamp. 92 at its center extending perpendicularly therefrom. for the purpose of receiving the end of the cross beam. 54. As shown at Fig. 5, the'soc'ket 92 may be see cured by rivets, bolts, welding or the like to the supporting post 91, as at. 93,, and may have the cross arm 54 Secured thereto as by a screw or projections 94. For as? Scmbly, with screw 94 loosened, cross, arm 54isii1serted into the socket 92. with the screw shaft. registering, with slots of socket 92. The slots 100 have right-angled branches into which screws 94 seat. Then a wing nut 94a may be tightened on screw 94 to make a rigid structure. It will be understood that while this is a simple and convenient arrangement for joining the cross beam 54 to the supporting arm 91, other equivalent means may be utilized.

For purposes of ease of packing and shipment, and of assembly-on the job, each of the dipoles 51, 52 and 53 is pivotally joined to the supporting post 91 so that this subassembly can be folded with post 91 essentially parallel to all three dipoles superposed on one another, and the assembly is adapted upon unfolding to be locked or clamped to the post 91 perpendicularly thereto. For this pulpose, each of the short dipoles 52 and 53 has a clip 95 secured thereto as by a long rivet 96 passing diametrically through the supporting post 91 and through the tubing 86 forming the long side of the dipole, at its center. 9512,- each having a groove formed therein to receive the dipole tubing 86. Clip portion 95b is formed with an elongated flat portion 97, having a pointed detent 98 extending at right angles therefrom. When the short dipole 52 or 53 is rotated about the pivot axis formed by rivet 96, to a position of perpendicularity to the supporting post 91, the detent 98 slips into a hole 99 formed in the supporting post 91, and serves to retain the dipole in this perpendicular relationship to supporting post 91.

The clip 95 is formed of two sections 95a and It will be understood that the clip portion 97 has sufficient resilience to permit the detent 98 to spring into and be retained in the hole 99 for locking the dipole in place. Also held by the rivet 96 is a rigid wire support 101 having an eyelet at its opposite end which is riveted as at 102 to the center of the insulating block 89 which spaces the terminal ends 88 of the short dipoles 52 and 53. This wire 101 serves to maintain the end terminals 88 of the short dipoles 52, 53 in rigid relationship to the remaining structure.

As shown in Figs. 2 and 5, the long dipole 51 is similarly pivotally secured to the supporting post 91 by a long rivet 103 passing through post 91 and the tubing section 71 of the long dipole 51. A clip 105, having portions 105a and 105b, is also secured to the dipole tubing The cross beam 54 is preferably pivotally connected to the screen 56, as shown in Fig. 1, by being pivotally secured to the center enlarged horizontal supporting bar 113 of the screen 56. Suitable clamping means, shown generally at 110, are provided so that the cross arm 54 may be locked into position perpendicularly to the plane of the reflector screen 56, as by way of a suitable wing nut, and slot arrangement of the general character of plate 106 and screw 108 of Figs. 2 and 5. The screen 56 is also made collapsible by having all of its horizontal rods 57 pivotally secured to the vertical rods 58. At the points 114 at which the vertical rods 58 cross the center horizontal rod 113, locking means may be provided to maintain the screen locked in its proper open position. For example, a vertical groove may be formed in the outer surface near each end of the center rod 113 to ac commodate one of the vertical rods 58 and the pivot at points 114 may be formed by wing nut and screw arrangements which rigidly clamp the vertical rods 58 to the horizontal rod 113 in only one position where the rods 58 seat in the said grooves so that these rods 58 and 113 are perpendicular to one another. The entire screen is then looked into proper relationship by this arrangement. The mast 55 may be clamped to the cross beam 54 by a conventional type of U-clamp 115, as shown in Fig. 1.

As an important aspect of the invention, it will be noted that each of the dipoles is conductively connected to the mast, at .the center of the long uninterrupted conductor thereof, opposite its terminal block. At this point, because of symmetry considerations, the antenna is at fixed potential and is hence grounded, serving asa pro tection against lightning injury to the receiver.

1 of the type described above.

71 by the rivet 103. Clip portions 105a and 1051) have grooves formed therein for receiving the dipole tubing 71. Clip portion 105i) is extended in a flat plate 106 shown in Fig. 2, having a slot 107 for receiving a screw 108 passing through the supporting part 91 and having a wing nut or similar type clamping means 109 at the other end. In this way, the long dipole 51 may be swung at right angles to the supporting post 91 to a position where the screw 108 engages with the slot 107 of the clip portion 106. Tightening nut 109 then clamps the long dipole 51 in proper position rigidly.

' A rigid wire support 111 is also secured by rivet 103 to tubing 71 and extends to the insulating block 77 join ing the ends 76 of the long dipole 51 to maintain the dipole portions in proper electrical and mechanical relationship.

The ends of the branches 83 and 84 of the coupling harness are riveted respectively to the ends of the short dipoles 52, 53 by the same rivets which connect these dipole ends to their insulating blocks 89 and 90, and the other ends of these harness branches 83 and 84 are joined together to the terminals 81 of terminal block 82.

It will thus be seen that the collapsed assembly of dipoles 51, 52 and 53 and the supporting arm 91 is easily unfolded into operative position merely by rotating each of the short dipoles 90 until its detent 98 snaps into hole 99. Similarly, the long dipole is rotated 90 and clamped in position by the screw 108 and wing nut 109. The cross beam 54 is then inserted in the bayonet type socket 92 and secured by the screws 94. The terminal block 82 may then be secured to cross beam 54 by a screw passing through holes 80 and 121 in the block 82 and beam 54, respectively.

In instances where it is important to provide a higher gain, the invention may be utilized in a stacked array having multiple bays, one above the other. Fig. 7 illustrates a two-bay arrangement formed by two units Each of the dipole assemblies 134 is as described above, each being secured to a respective cross beam 54, which in turn is clamped in the manner already described to its respective reflector screen 56. For the purpose of joining the two reflector screens into a single screen, the ends of vertical rods 58 are flattened and apertured in a manner similar to that in which dipole rods 71 and 73 are flattened and apertured as shown in Figs. 2 and 3, so that the two aligned vertical rods 58 can be bolted together as at 141. Aligned ridges and grooves may be formed in these flattened ends to maintain their alignment seated on one another as shown in Fig. 8.

The mast S5 is then clamped at 115, to each cross beam 54. A further coupling harness is provided, having a terminal block 136 from which respective transmission line branches 137 of equal length proceed to the respective terminal blocks 82 of the individual bays 134, secured to the cross beams 54 as described above. A further terminal block 138 is mounted on mast 55 between the cross beams 54, and a line section 139 extends from block 138 to block 136. The line sections 137 and 139 are preferably formed by rigid rods, the sections 137 serving properly to space the two dipole assemblies, and section 139 holding sections 137 rigidly in place. The down lead transmission line 23 is then secured to the terminals on block 138. In a similar manner a four-bay arrangement may be provided, by connecting down lead 23 to the center of a line section connecting two terminal blocks 138.

The dipole construction disclosed hereinabove is also disclosed and claimed in divisional application Serial No. 485,575, filed January 18, 1955, and entitled Antenna Structure. It will thus be seen that the present invention provides a simple and eflicient wide-band antennna arrangement, easy to fabricate and assemble, and effective over the entire VHF range of broadcast television.

It is to be understood that the above description is I illustrative only, since equivalent structural features may be utilized where desired, the present invention being defined by the appended claims.

What is claimed is:

1. A collapsible screen type reflector for antennas comprising a plurality of parallel horizontally disposed conductive rods, a pair of vertical conductive rods pivotally secured to each of said horizontal rods, said vertical rods being generally parallel to each other and cooperating with said horizontal rods to form a collapsible grid, and clamping means at the juncture of each of said vertical rods with the center one of said horizontal rods for clamping said vertical rods in perpendicular relation to said horizontal rods.

2. A screen reflector as in claim 1, wherein the center one of said horizontal rods is larger in diameter than the others, and further including a cross beam pivotally connected to said larger horizontal rod at the center thereof, and means for clamping said cross beam in perpendicular relationship to the plane of said horizontal rods.

3. A screen reflector as in claim 1, wherein the center one of said horizontal rods is larger in diameter than the others, said clamping means comprising a groove formed integrally in and extending perpendicularly across said larger horizontal rod at each of the junctures thereof with said vertical rods, and fastening means for securing each of said vertical rods to said larger horizontal rod I with each of said vertical rods disposed in a respective one of said grooves, whereby said vertical rods are maintained perpendicular to said horizontal rods.

4. A reflector as in claim 1, wherein the topmost and bottommost ones of said horizontal rods are shorter than the remaining horizontal rods, whereby said reflector is made substantially non-resonant.

5. A collapsible screen-type reflector tfor antennas adapted for single-bay or multi-bay use, comprising a plurality of parallel horizontally disposed conductive rods, a pair of vertical conductive rods each pivotally secured to each of said horizontal rods, said vertical rods being generally parallel to each other and cooperating with said horizontal rods to form a collapsible grid, means for clamping said vertical rods in perpendicular relation to said horizontal rods, each end of each of said vertical rods being apertured with corresponding ends of said vertical rods being formed with a ridge extending therea-long and the remaining ends of said vertical rods being formed with a groove extending therealong and of a size mating with said ridge, whereby two of said reflectors may be bolted together through said apertures and maintained with their vertical rods in alignment by said ridges and grooves.

6. A multi-bay antenna array comprising a mast and a pair of antenna arrangements supported on said mast in vertically spaced relation, each of said arrangements comprising a cross beam, an antenna secured to one end thereof and a screen reflector secured to the other end thereof, each of said reflectors comprising a plurality of horizontal conductive rods and a pair of vertical conductive rods, each pivotally secured to each of said horizontal rods, and means for rigidly maintaining said horizontal rods perpendicularly of said vertical rods, the vertical rods of one of said reflectors being secured respectively to the vertical rods of the other reflector to form a continuous composite screen reflector for said array.

7. An antenna array as in claim 6 further including means pivotally securing each of said screen reflectors to its respective cross beam, and means for clamping each said screen reflector to its said respective cross beam with the reflector plane perpendicular to said cross beams.

References Cited in the file of this patent UNITED STATES PATENTS 85,595 Lambkin Jan. 5, 1869 404,856 Ogilvie June 11, 1889 496,123 Keuflel Apr. 25, 1893 792,393 Brust June 13, 1905 2,492,529 Kaplan Dec. 27 1949 2,496,646 Winer Feb. 7, 1950 2,523,531 Flippen Sept. 26, 1950 2,691,730 Yuen Tze Lo Oct. 12, 1954 OTHER REFERENCES Radio and Television News, May 1951, page 103

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