GB367004A - Improvements in electrical resistance devices - Google Patents

Abstract

367,004. Ribbon resistances ; couplings. LIGHTFOOT, E. N., Wanwatosa, Milwaukee, Wisconsin, U.S.A. Nov. 5, 1930, No. 33284. Convention date, Feb. 19. [Classes 37 and 38 (i).] A resistance ribbon is supported by being bent back and forth between two sets of metallic supports mounted on, and insulated from, respective metal rods. Between endplates 35, 36, Fig. 1, are mounted a pair of rods 20, 21 covered with tubes of insulating material such as laminated mica. On these are strung metal plates 23 alternately with insulating washers 33. The plates 23 are shown in Fig. 6, and have a hole 24 fitting over the insulating tube, and a pair of deep notches 25, 26 which support the resistance ribbon while permitting expansion. The plates 23 are arranged to extend in diametrically opposite directions so as to provide supports for two resistance ribbons 45, one on each side of the rods 20, 21. The assembly is tightened by nuts 29. Each ribbon 45 is bent as shown in Fig. 5 and, if thin, may have reinforcing corrugations 46 at the bends and beads 47 between the bends. The bends engage the notches 25, 26 in the plates 23. The terminal elements, shown in Fig. 7, comprise stamped plates 48, 48a having stampedout lugs 49, 49a which engage perforations 27,28, Fig. 6, in the plates 23. The lower ends of the plates 48, 48a have bowed portions engaging the bends in the ribbon 45. At their upper ends, the plates 48 have corrugations 51, 52 for clamping wires of different sizes. Between the plates 48, 48a is a plate 53, Fig. 9, having an offset lower portion and a partially severed portion 56 which engages the notch 25 or 26 supporting the bend of the ribbon. Perforations 73 permit the attachment of metal tags indicating the value of the resistance at the different tapping points. One of the plates 48, 48a may be omitted. For connecting two resistance strips in parallel, metal plates 64, Fig. 11, having flat offset portions 65, 66, and a connecting portion 67 may be employed. Plates 48, as shown in Fig. 7, are employed in co-operation with the portions 65, 66, the intermediate portion 67 being perforated to take a bolt by which a cast-iron terminal clamping element is secured thereto.