US 3505463 A
Description (OCR text may contain errors)
April 7, 1970 J. H. M ADAMS 3,505,463
I RADIO FREQUENCY ENERGY BARRIER MATERIAL Filed April 8, 1968 2 [HEIGHT I $I?S U L A T IN Z; OR
Am 4 I4 FIG. 3A FIG. I CONDUCTIVE OR INSULATING 9 CONDUCTIVE FIG. 3B OR INSULATING 7 3 I I4 CONDUCTIVE OR INSULATING I2 I8 FIG. 3C
CONDUCTIVE OR INSULATING James H. McAdcIms,
United States Patent O 3,505,463 RADIO FREQUENCY ENERGY BARRIER MATERIAL James H. McAdams, Huntsville, Ala., assignor to the United States of America as represented by the Secretary of the Army Filed Apr. 8, 1968, Ser. No. 719,590 Int. Cl. F16j 15/12; Hk 9/00 US. Cl. 174-35 3 Claims ABSTRACT OF THE DISCLOSURE A configuration of electrical conducting, flexible wires or members arranged to have a height, width, and length. The barrier material being inserted between two conducting surfaces forming portions of an RF. energy barrier enclosure.
DEDICATORY CLAUSE The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.
BACKGROUND OF THE INVENTION Shielding devices for covering openings in the past have been in the form of conventional door structures and have not been sufiiciently effective since these doors have failed to provide a complete shield for the opening. The reasons for this is that unles one makes the door fit within very close tolerances, a gap or interstice will occur, and electromagnetic energy may pass therethrough. Further, the joining of any two surfaces, such as connecting flanges in waveguides, has the gap problem. There is, therefore, a need for the present invention which fills these gaps with an RF. barrier material while at the same time allowing the surfaces to be made at normal or even at large tolerances.
SUMMARY OF THE INVENTION The RF. energy barrier material in one embodiment is a wire which is wound, sewn, or formed into an essentially rectangular or coil shape wherein the individual turns of the wire are made to lie side by side. This will give the material height, width, and length dimensions. In another embodiment, rings or cups placed side by side at one or more edges of a core could be used. The barrier material can be used by itself by placing it in a slot or trough which is formed in the door of wall of the enclosure to be shielded. The barrier material can also be wound around, sewn into, or clipped onto a flexible core. The core can be made of insulating or conducting material which may have a greater or lesser resiliency than that of the barrier material. The purpose of the invention is to provide an electrical conducting path between two surfaces of an enclosure used to restrain transmission of radio frequency energy. The two surfaces generally being in imperfectelectrical contact and mechanical fit. The barrier material is resilient and arranged so that each turn has essentially an independent action in conforming mechanically to variations in the spacing of the surfaces of the enclosure. Therefore, it permits each of the closely spaced turns to electrically contact the surfaces and complete an electrical circuit. This reduces the space between the surfaces through which the electromagnetic energy can pass.
BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a diagrammatic representation of one embodiment of the invention;
FIGURE 2 is a diagrammatic showing of the use of the embodiment of FIGURE 1 between two surfaces;
FIGURES 3A-C all show possible end views of embodiments such as that shown in FIGURE 1;
FIGURE 4 shows the use of the invention in a slot contained in one of the two surfaces;
FIGURE 5 is a diagrammatic representation of another embodiment of the invention;
FIGURE 6 is a showing of a possible end view of the embodiment shown in FIGURE 5; and
FIGURE 7 shows the use of the embodiment shown in FIGURE 5 in a slot contained in one of two surfaces.
DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGURE 1 shows an electrically conductive material 1 in the shape of a wire, such as a copper wire, which is bent into an essentially rectangular shape. The turns are shown far apart in FIGURE 1 so as to show the details. In the actual embodiment all the turns will lie side by side. This will give the wire height, width, and length dimensions. The barrier material 3 being made of a wire or wire-like material will be flexible, and when it is placed between two surfaces 4 and 5, as shown in FIGURE 2, it will make contact with both surfaces all along its length without being a perfect fit.
The wire 1 of the material 3 can be shaped into a rectangular shape, as shown in FIGURE 3A, or it could contain one or two indentations, as shown in FIGURES 3B and 3C. Indentations could also be formed in the other sides of the rectangle as shown in FIGURE 4. .These indentations serve to specifically locate the points at which electrical contact is made and/or to modify or relocate the area in which resilience is experienced. The indentations further provide areas where contact members other than a plane surface may be utilized. FIGURE 4 shows one possible protruding surface, that being a round rod 7 which is attached to or is a part of a door or wall 9. Other protruding shapes such as triangular, trapezoidal, etc. could be used for the rod 7. The other surface 10 has a slot or trough 12 in which barrier material 3 is fitted. For details of how the barrier material may be used in a slot or trough, see US. Patent No. 3,296,356 which was issued to applicant on January 3, 1967.
A core 14, seen in FIGURES 3A and 3C, of insulating or conducting material such as rubber or steel wool may be inserted within the opening of the barrier material, or the barrier material could be formed around the core. The core may have a greater or lesser resiliency than that of the barrier material, and -it may have other desirable features. The core may fit only within the barrier material (FIGURE 3A), or it may encompass a portion of the turns of the wire (FIGURE 3C). The core can, of course, be made any configuration and have any properties which may be desired by one skilled in the art.
If a core is to be used, then the wire may be sewn or clipped in the core, or the core could be formed about the wire. This is shown in FIGURES 5-7. In FIGURE 5, rings or cups 16 are clipped onto one edge of the core 18. On the other edge of the core is a wire 20 which is sewn in the core. Wire 20 will be in the form of a coil or spiral after it is sewn in the core. The rings and the turns or loops of the wire are shown far apart in FIGURE 5 for clarity; however, in the actual embodiment they will be placed side by side to again form a barrier material having three dimensions. Either one or both edges of the core may have the barrier material. Where both edges are used, the device may be as shown in FIGURE 5, or both edges of the core may have the rings, also both edges may have the coil configuration. In these embodiments, additional resiliency and surface conformance is achieved when a protruding contact member 22 is used as shown in FIG- URE 7. Additional contact points are also achieved when any of the embodiments are installed in a slot, groove, trough, or device 24 which encloses the barrier material on three sides as shown in FIGURE 7.
In the embodiments of this invention, the conductors are arranged at right angles to the longitudinal axis of the barrier material. By this arrangement, the shortest possible conducting path is presented to any induced electrical current. Because of the numerous closely spaced individually respondent, resilient, springy, electrical contacts, the electrical resistance path between the two conducting surfaces is reduced Without a necessity for a high degree of smoothness or alignment of the two surfaces when closed together.
1. A system comprising a core means having at least first and second edges, two electrically conductive wirelike means attached to the edges of the core means, said wire-like means being in the configuration of a plurality of rings clipped onto the core means and positioned side by side so as to present height, width, and length dimensions, one of the wire-like means being attached to the first edge of said core means, the other wire-like means being attached to the second edge of said core means, first and second surfaces which are to be placed in electrical contact with each other so as to prevent the passage of electromagnetic energy therebetween, a trough positioned on said first surface and in electrical contact therewith, said wire-like means being positioned in said trough and ber positioned on said second surface and in electrical contact therewith; and said contact member 'being in con- 10 tive wire-like material which is in the configuration of a 15 and a flexible core means which is positioned within said turns.
References Cited UNITED STATES PATENTS 1,733,880 10/1929 Hurxthal 277235 XR 2,084,523 6/1937 Crawford. 1, 2,469,474 5 1949 Perry. 3,126,440 3/ 1964 Goodloe. 3,259,406 7/ 1966 Kish.
25 FOREIGN PATENTS 871,176 3/1953 Germany.
DARRELL L. CLAY, Primary Examiner 0 Us. (:1. X.R.