GB528757A - Improvements in and relating to electrical resistances - Google Patents

Abstract

528,757. Grid resistances. HUHNE, H. P. May 4, 1939, No. 13328. [Class 37] The loops of each element of a corrugated tape resistance are adjustably mounted between counterpart insulated clamping members which also serve as separators, the clamping members being perforated, shaped, and dimensioned so as to project from one or each side of the rod upon which they are adjustably assembled, together with insulators, the rod being furnished with clamping means so that the loops may be longitudinally adjusted. On rods or tubes 1 are slidably mounted a plurality of perforated intermediate clamping members 2 and interposed perforated mica, porcelain, or other insulators 3 between perforated slidable end clamps 4. so that the loops or bends a, a<1> of two strip resistances can be spaced apart and secured between corresponding insulators 3 and clamps 2, 4 by means of nuts 5. Each of the loops a, a<1> is stiffened by corrugations the number and arrangement of which varies with the width of the strip. Plain portions are left between the corrugated portions to permit the strip to be bent into loops. The corrugations are V-shaped to correspond with counterpart V-shaped projections and recesses 7, 8 on the clamping elements 2, 4, while the interposed insulators 3 are correspondingly shaped. In the case of wide resistance strips of a V-shaped corrugation may be formed near one edge of each of the loops a, a<1 >in addition to smaller longitudinal and transverse corrugations, so that such elements are secured at one edge in the insulated clamps. The intermediate clamping members 2 may be made from sheet metal such as aluminium or aluminium alloy and the corrugated ends thickened with layers of sheet metal or they may be cast in aluminium &c. with the corrugated ends thickened. Tappings may be taken by inserting contact plates of copper &c. between the resistance loop to be tapped and the insulators on each side of it, the contact plates being formed with corrugations corresponding to those on the resistance strip. The rods 1 are mounted in an angle-iron frame, which may be enclosed with panels and doors or removable covers.