GB671881A - Electrically heated curtains or blinds - Google Patents

Abstract

671,881. Electrically-heated curtains or blinds. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. Aug. 9, 1950 [Aug. 11, 1949], No. 19779/50. Class 39 (iii). A heated curtain or blind 1 comprises a rectangular sheet of plastic material or textile reinforced by plastic having incorporated therein a carbon powder forming a coherent electrically conductive skeleton current being supplied thereto by contacts extending along opposite edges. The plastic has a resistivity of 10-1,000 ohms per cm.<SP>3</SP> and may comprise a halogen-containing plastic containing polyvinyl chloride or vinylidene chloride, chlorbutadiene or halogen derivatives of polyethylene. After measuring the resistivity, a central slot 3 of such width as to give the desired resistance is punched in the sheet and flexible conductors 2<SP>1</SP>, 2<SP>11</SP> are impressed to give a U-shaped curtain, the conductors being connected to spaced contacts on the curtain rod. Sheets of insulating plastic may be welded to one or both sides and may be larger than the heating sheet. The insulating sheets may be welded together only at the edges and in the central slot 3, either by hot plates by dielectric heating or by sticking. The curtain is opaque, and the slot 3, which need not extend to the edges may be filled by a strip of black plastic. A conductor 2" at the lower edge may pass up inside the plastic pocket, the two conductors being led out as a double wire cable. A roller blind comprises a conductive sheet 1 with a non-condrctive sheet 4 on one side rolled about a roller 8 containing thermostats and attached at the base to a conductive bar 9 with end projections or spring- pressed pins engaging contacts in grooves on a window frame. Contact may be made only when the blind is fully lowered. one turn of the blind remaining on the roller. One or two contact bars are mounted preferably in a groove on the roller 8. the outer ends of the bars contacting mounting pins on the roller The blind is held in the groove by a helical spring or rubber' rope or by a rod 10 held by screws 12.