Improvements in or relating to the manufacture of telephone selector banks and like electrical apparatus

摘要

364,192. Automatic exchange switches. PATTMAN, W. E., Fairlight, Kineton Green Road, Olton, Warwickshire, SHERWOOD, A. W., 52, Princes Avenue, Church End, Finchley, and BAKELITE, Ltd., 68, Victoria Street, both in London. Oct. 7, 1930, No. 30054. [Class 40 (iv).] Switch banks and the like are built up by assembling rows of terminals with intervening layers of fibrous material, e.g. paper, fabric, silk, impregnated with a potentially reactive synthetic resin, pressing the assemblage at a temperature at which the resin softens, and then further heating it to harden the resin. The resin may be a condensation product of phenol- or urea-formaldehyde. A bank may be made complete as a unit or in several parts subsequently joined together.