Ventilation aperture for shielded enclosures

Claim 2

An improved ventilation aperture for use in a shielded enclosure wherein the aperture includes at least one waveguide below cutoff-type grill inserted within a magnetically shielded duct attached to the enclosure, the improvement comprising improved means for sealing the waveguide grill to the duct interior said means comprising: a waveguide below cutoff type grill positioned within the magnetically shielded duct; a first magnetically shielded frame member sealed within the inside periphery of the duct; a second magnetically shielded frame member positioned within the duct and spaced far enough apart from said first frame member to accommodate said waveguide grill between said members; first and second resilient conductive elements sandwiched between the outside and opposing peripheral surfaces of said grill and the abutting surfaces of said first and second frame members; and means for applying and maintaining uniform pressure against the free surface of said second frame member whereby said pressure is transmitted to said first and second conductive elements resulting in close electrical contact between said elements and abutting wAveguide grill and frame member surfaces.

Claim 3

An improved ventilation aperture as described in claim 1 wherein said first and second resilient conductive elements are strips of woven ferromagnetic mesh.

Claim 4

An improved ventilation aperture as described in claim 1 wherein a film of highly conductive, noncorrosive metal is sandwiched between said first and second resilient conductive elements and all surfaces abutting said strips.

Claim 5

An improved ventilation aperture as described in claim 1 wherein said means for applying and maintaining uniform pressure against the free surface of said second frame member comprise a plurality of retaining elements extending through both frame member and duct wall and serving to maintain the frame member stationary in a previously determined, pressure-applying position.

Claim 6

An improved ventilation aperture as described in claim 4 wherein said retaining elements are pop rivets.

Claim 7

An improved ventilation aperture for a shielded enclosure comprising: a straight magnetically shielded duct; a waveguide grill positioned within said shielded duct and inclined to a sufficient angle so as to prevent direct impingement on the grill core cells of magnetic lines of flux entering the outside end of said duct; a first magnetically shielded frame member sealed within the inside periphery of said duct; a second magnetically shielded frame member positioned within said duct and spaced far enough apart from said first frame member to accommodate said waveguide grill between said members; first and second resilient conductive elements sandwiched between the outside and opposing peripheral surfaces of said grill and the abutting surface of said first and second frame members with portions of said conductive elements being of wedge shape so as to offer a complementary inclined surface to the respective inclined grill surface and a vertical surface to said frames; and means for applying and maintaining uniform pressure against the free surface of said second frame member whereby said pressure is transmitted to said first and second conductive elements resulting in close electrical contact between said elements, the abutting waveguide grill and frame member surfaces.

Claim 8

An improved ventilation aperture for a shielded enclosure comprising: a straight magnetically shielded duct; a waveguide grill positioned within said shielded duct and inclined to a sufficient angle so as to prevent direct impingement on the grill core cells of magnetic lines of flux entering the outside end of said duct; a first magnetically shielded frame member sealed within the inside periphery of said duct; a second magnetically shielded frame member positioned within said duct and spaced far enough apart from said first frame member to accommodate said waveguide grill between said members; first and second resilient conductive elements sandwiched between the outside and opposing peripheral surfaces of said grill and the abutting surface of said first and second frame members with portions of said conductive elements being of wedge shape so as to offer a complementary inclined surface to the respective inclined grill surface and a vertical surface to said frames; and means for applying and maintaining uniform pressure against the free surface of said second frame member whereby said pressure is transmitted to said first and second conductive elements resulting in close electrical contact between said elements, the abutting waveguide grill and frame member surfaces.