CA1213967A - Wire mesh gasketing - Google Patents

Abstract

ABSTRACT
An arrangement for preventing electromagnetic radiation from passing an access opening, in a sheet of elect-romagnetically opaque material, having a closure of similarly opaque material with a surface urged against the surface of the sheet at the opening, comprising an elongated strip of wire mesh gasket extending beside the opening in contact with the surfaces, and being of generally circular cross section with a fin extending laterally therefrom toward and through the opening, and wear strips securing the fin to both surfaces of the sheet at the opening.

Description

BRIEF _ M~ARY OE THE I _E_TION
The present invention comprises a procedure whereby relatively unskilled personnel are able to install radiation--tight seals around openings of any size much more quickly and inexpensively, withou-t any tooling or set--up charges, the seals being capable of repair or replacement in the field without special tools.
According to the invention, there is provided in combination: a shee-t of electromagnetically opaque material having a polygonal access opening therein; a gaske-t strip of woven wire el.ectromagne-tically opaque material extending around the periphery of said opening, said strip comprising, in cross section, a generally circular portion from which a fin extends radially; means securing said strip around said opening so that said circular portion engayes one surface of sai.d sheet and so that said fin engages both surfaces of said sheet, passing through said opening to do so, said strip securing means comprising resilient wear strips of generally U-shaped cross-section substantially longitudinally co-extensive wi-th said edges of said opening ancl comprising in section first and second legs extending in the same direction from a common bigh-t and mutually spaced to press said fin firmly against the surfaces of said shee-t, said circular portion being continuous around the corners of said opening and being of greater diameter than the thickness of a leg of said wear strip, to enable compression of said circular portion and to limit the amount of said com-pression; and a closure of electromagnetically opaque material larger than said openiny and opposed -thereto, so that when said closure is pressed against said gasket strip said circuit portion -thereof forms a continuous seal surrounding said open-ing.

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BRIEF DESCRIPTION OF THE DRAWING
_ _ _ _ _ _ _ _ _ _ _ _ In -the drawing, in which like reference numerals indicate corresponding parts throughout the several views, FIGURE. 1 shows a radia-tion seal according to the inven-tion installed around an access opening in a housing, FIGURE 2 is a fragmentary sectional view of a seal accordi.ng to -the inventi.on in relation to a housing and a closure, and FIGURE 3 is an enlarged, detailed vi.ew of a portion of FIGURE 1.
DESCRIPTION _ T~IE PREFERRED EM~ODI~ENT
As is shown in the drawing, a cabinet or housing for equipment producing electromagnetic radiation includes a wall 20 having an access opening 21, with which a closure 22 cooperates by hinging, clamping, or other appropriate measures.
A strip of woven wire gasket 24 is mounted to surround opening 21. In cross-section, gasket strip 24 comprises a generally circular portion 25 from which a fin 26 extends laterally toward and through opening 21, being folded over the edge 27 of the opening. Gasket strip 24 may be preformed in the exact size to fit around opening 21, or may be made on the spot from a length of material, the ends being mutually twisted and intertwined to form a continuous bond, and the joint preferably being located at a site other than a corner of the opening. In order to give a more perfect configuration~ fin 26 only of strip 24 may be mitered at the corners, as shown at 30 in FIGURE 3.
In order to secure gasket strip 24 in position, a set of wear strips 31, 32, 33 and 34 are provided. These strîps are of slightly less length than the sides of opening 21, and may be of nylon or other suitable material. They are of U-shaped configuration in cross-section, comprising first and second legs 35 and 36 extending in the same direction from a bight 37. The spacing bet~een the legs is substantially the same as the thickness of wall 20 plus twice the thickness of fin 26. See FIGURE 2.
To install the seal, gasket strip 24 is placed at opening 21 and fin 26 is passed through the opening and folded along the surfaces of wall 20. Starting near one corner, a 7~

wear strip such as 34 is pressed over the fin and the end of the wall, and this is continued unt~l the entire length of the wear strip is tightly engaged. This is repeated at the other edges of ~he openingr until the gasket strip is firmly secured all around the opening. The wear strips come suffi-ciently close to the corners to give adequate holding of the gasket strip, but a mitered corner is not found necessary.
FIGURE 2 shows that the diameter of the gasket strip is greater than the thickness of the wear strip r SO
that the gasket strip can be compressed between door surface 40 and housing surface 41, while the wear strip acts as a mechanical stop to prevent undue compression of the gasket strip.
In one embodiment of the invention, the gasket strip was of Monel Mesh material supplied by Tecknit, and the wear strip was of molybdenum disulfide Filled Nylon, supplled by Polymer Corp. For a housing of .060 to .090 thick gauge metal the diameter of the gasket strip 24 was 3/16 inch and the width of fin 26 was .750 inches. The dimensions of wear strips 31-34 were .23 x .32.
While the sPal has been shown as applie~ to the housing around the opening, it can with equal satisfaction be applied to the edge of a closure of proper dimensions.
From the above it will be evident that the invention comprises an arrangement for sealing an opening against passage of electromagnetic radiation without special frames or fas-ceners f which can be accomplished readily and inexpensively by xelatively unskilled labor.
- Various characteristics and advantages of the invention ha~e b~en set forth in the foregoing description, together with details of the structure and function of the inventi~n, and the nov~l features thereof are pointed out in the appended claims. The disclosure, however, is illustxative only, and changes may be made in detail, especially in matters of shape, size~ and arrangement of parts, within the principle of the in~ention, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In combination:
a sheet of electromagnetically opaque material having a polygonal access opening therein;
a gasket strip of woven wire electromagnetically opaque material extending around the periphery of said opening, said s-trip comprising, in cross section, a generally circular portion from which a fin extends radially;
means securing said strip around said opening so that said circular portion engages one surface of said sheet and so that said fin engages both surfaces of said sheet, passing through said opening to do so, said strip securing means comprising resilient wear strips of generally U-shaped cross-section substantially longitudinally co-extensive with said edges of said opening and comprising in section first and second legs extending in the same direction from a common bight and mutually spaced to press said fin firmly against the surfaces of said sheet, said circular portion being continuous around the corners of said opening and being of greater diameter than the thickness of a leg of said wear strip, to enable compression of said circular portion and to limit the amount of said compression;
and a closure of electromagnetically opaque material larger than said opening and opposed thereto, so that when said closure is pressed against said gasket strip said circular portion thereof forms a continuous seal surrounding said opening.