GB647268A - Improvements in or relating to apparatus for use in detecting the passage of wheeledvehicles - Google Patents

Abstract

647,268. Gas compressors. SIEMENS & GENERAL ELECTRIC RAILWAY SIGNAL CO., Ltd., CARPENTER, A. R., and RIDDLE, H. J. N. Oct. 29, 1947, No. 28895. [Class 8(i)] '[Also in Group XXXVIII] A detector pad for indicating the passage of vehicles by the displacement of fluid in a flexible container comprises two or more base members adapted to be secured to a solid foundation and shaped to provide two channels, as shown in the sectional view of Fig. 6, for the flexible tubes 8, and to fit over two parallel metal bars 1 which are anchored at their ends to termination boxes 2 (Fig. 1, not shown), and ensure that the channels in adjacent base members are collinear. The wing portions 5 and central plate 7 may be perforated to ensure adhesion to the concrete in which the members are embedded. A small gap is left between adjacent base members so that the framework bars 1 can be bent slightly to enable the pad to follow the camber of the round surface. Each flexible tube 8, which may be of reinforced rubber, is held :in position by a curved resilient bar 9, which fits inside the tube 8, extending throughout the length thereof,. and is clamped at each end by a connecting block 10, Fig. 5, being thereby forcibly straightened. Each tube 8 projects slightly above the top surface 11 of the base members in order that it may be depressed by vehicles passing over the pad.. The blocks 10 also serve to make connection between each flexible tube 8 and the pipe line (not shown) which connects the nipple 12 to associated pneumatic apparatus. The tube 8 is a push fit on a nipple 13 and is secured thereon by clips 14; a sealing compound may also be used. One flexible tube only may be used, but two permit differentiation in respect of traffic direction. Loosely packed cotton waste, flock or kapok in open-weave canvas or webbing tubes may be inserted in the flexible detector tubes to damp air column oscillations.