Improvements relating to triangulated frameworks and their application to the construction of military bridges and the like

摘要

540,945. Bridges ; metal girders. INGLIS, C. E., and KRYN & LAHY (1928), Ltd. April 30, 1940, No. 7747. [Classes 20 (i) and 20 (ii)] A method of building a bridge of lattice construction consists in assembling one girder comprising upper and lower boom and interbracing members of tubular section, and launching it, and then assembling supplementary girders of similar construction, in sites alongside the positioned section and connecting them thereto The girders having the same general characteristics as those described in Specifications 22079/14 and 112184, [both in Class 20 (i)], are each built up of tubular members 10, 11, 27 joined together to form a warren girder by four-way sockets 3, Fig. 5, at their lower ends and six-way sockets 4, Fig. 8, at their upper ends, opposed lower sockets being bolted to transverse bearers 6 on which the floor of the bridge is supported. The main girder is launched and then the supplementary girders on each are built up in situ and in order to allow these supplementary girders to be attached to the bearers depending pivoted bolts 19 are provided on the lower socket members to coact with clamping straps 21 which bear against the under sides of the bearers as described and claimed in Specification 540,956. The upper and lower socket members are also provided with transversely disposed apertures 29 to receive through bolts 53, Fig. 12, provided with end nuts and intermediate conical sleeves 34 to engage and distance the socket members of adjacent girders and whereby the girders on each side are connected together. The upper two apertures of upper socket members may be used to connect further bracing members for a superposed girder where this is required for great spans, or may be used to receive depending bolts 44 from pedestals 42 which are adapted to carry upper cross bracing members between the girders on opposite sides of the bridge. The joint between a tube and a socket is shown in Fig. 10, in which an apertured member 15 is screwed to the end of a tubular member and enters an aperture of a socket to receive a crosspin, the joint being tightened by a screwed sleeve 12 adapted to bear on a bearing surface 14 provided around the exterior of each aperture in each socket. To provide inclined approaches for the bridge, the lower sockets are formed in two hinged portions 47, 48, Fig. 15, each portion provided with two connecting apertures. Adjacent tubular members in the main and supplementary girders are clamped together by clamps 39.