GB781605A - Improvements in or relating to shielding boxes and housings for radio and other highfrequency apparatus - Google Patents

Abstract

781,605. Radio apparatus. MARCONI INSTRUMENTS, Ltd. Oct. 6, 1955 [Jan. 18, 1955], No. 1469/55. Class 40 (5). A metallic screening enclosure for radio apparatus, comprising at least two parts which are separable to give access to the apparatus therein, is provided with expanded-metal mesh as shown in Fig. 1 between the meeting surfaces of the separable parts so that when the parts are bolted or otherwise clamped together the meshwork bites into the meeting surfaces and thus ensures that all parts of the enclosure are in good electrical contact with each other. The packing may consist solely of strips of the expanded metal arranged between the meeting surface, Fig. 3 (not shown); alternatively, as shown in Fig. 4, the mesh work 8 may be arranged around a rubber strip, preferably together with a thin copper foil 7, the mesh work 8 and foil 7 being held in place before insertion between the separable parts of the enclosure by means of staples 9. Fig. 6 shows a sealing ring according to the invention and comprising a polytetrafluoroethylene ring 12 around which are wound strips 8 of the expanded-metal mesh. Fig. 8 shows an arrangement providing a degree of hermetic sealing and comprising a rubber block 14 having slits 15, 16 into which are inserted the edges of a metal-foil inner covering 7 together with an expanded-metal outer covering 8.