GB584132A - Improvements in or relating to floating airfields, runways, bridges and the like - Google Patents

Abstract

584,132. Pontoon bridges. HAMILTON, R. M. Feb. 22, 1944, Nos. 3254/44 and 1634/45. [Class 20 (i)] [Also in Groups XXV, XXXII and XXXIII] A floating airfield, runway, bridge or like structure for supporting aircraft or other vehicles passing over water, comprises mosaic elements which are hinged together along zigzag or other lines which extend in a number of intersecting directions. The elements are preferably hexagonal, but they may be octagonal interspersed with diagonally-set squares, and their unloaded free board exceeds their depression when loaded. In the form shown, each element comprises a hexagonal deck plate 11 the upper surface of which is flat, roughened, corrugated, or ribbed, and the under surface of which is formed with substantially radial stiffening ribs 16 united by a central plate 17. The deck plate 11 overhangs the walls of a float chamber 12 which carries a bottom plate 13 with stiffening ribs 14, 15. The male and female parts 24, 25 of the hinges are arranged alternately around the sides of the hexagon. Each male part 24 is of rectangular U-shape, the arms of which are joined by a cross-piece 31, whilst each female part comprises a pair of upright plates 25 on each side of the male part. These parts 24, 25 carry packing pieces 36, 38 to bring their upper surfaces level with the deck. The plates 25 have openings to receive larger and smaller bushes 39, 139 which fit corresponding ends 41, 43 of a hinge pin 40, the centre of which has flat vertical faces 42 to fit the male part 24, and slightly barrel-shaped upper and lower faces 44 which permit slight relative twisting between the elements.. The hinge pin 40 has an eye 46 by which it may be chained to the deck plate 11, and it is held in position by a locking pin 47 which engages behind the end 41. The elements are also inter-connected by hydraulic piston-and-cylinder dampers 30 with stops, located just above the bottoms of the float chambers and substantially parallel to the hinges. Each damper contains two pistons 52, 53 held apart by a strong buffer spring 54, one end of the cylinder being closed by a plate 50 carrying an eye 51. One end of a piston rod 56 with a screwed-on head 57 slides through the piston 52, the other end passing through the piston 53 and screwed into a sleeve 58 which is slidable in a cover plate 59 and which carries an eye 60. The plate 50 and a tube 61 on the piston rod 56 serve as stops for the damper. The cylinder is formed with bleed holes 63-65 and with triangular clack valves 66, 67 for inlet ports 60, 70. The effective length of the damper is adjusted by teeth 72 on the hand tool shown in Fig. 10 engaging gear teeth 71 cut in the end of the sleeve 58. The eyes 51, 60 fit over pins 76 supported by brackets 77, the eyes 51, before connection to adjacent elements, being temporarily supported by pins 78. Binding of the pins 76 after assembly is prevented by tubes 80 with flanged heads 81. Specification 576,717 is referred to. According to the first Provisional Specification (i) a number of float chambers 12 are associated with each deck plate 11, (ii) the structure may be built up from plastics or concrete instead of steel, and (iii) each hinge and its associated damper may be replaced by a pair of hinges. According to the second Provisonal Specification single-piston dampers are employed.