GB609527A - Improvements in the mass production of reinforced concrete constructions - Google Patents

Abstract

609,527. Moulding prestressed concrete units. LONDON & NORTH EASTERN RAILWAY CO., and ABELES, P. W. March 11, 1946. No. 7499. [Class 87(ii)] Concrete units such as girders, beams, poles or sleepers are moulded in line around pretensioned reinforcing wires 6, Fig. 5, in moulds each consisting of a bottom plate 4, removable side walls 7, 8 slotted or perforated end plates 43 and cross-ties 11. In operation the wires 6 are cleaned, arranged in the required manner through the end plates and then tensioned, the mould parts are assembled around the wires and the concrete poured and vibrated. The side walls are removed as soon as possible and used in the erection of another mould. The units may then be positioned under canopies of heat insulating material and hot air introduced through pipes. When the units have hardened, the tension on the wires is relieved and the wires cut or burnt off and the units are removed by a conveyer or by an overhead trolley 51, Fig. 8. When a conveyer is used, separate units in a line may be separated after removal from the casting site. The units may be removed on the mould bottoms. The moulds are filled from a hopper 44 or from containers 47 on a transverse beam 46. The moulds are vibrated by external overhead or internal vibrators. In a modification, the mould bottoms may be mounted on springs or rubber blocks on vertical columns and vibrators are moved along a rail, fixed to the mould bottoms, until they are in the desired position, where they are secured by wedges. The mould sides are secured to the bottom by bolts, pins, clips or hinges. Longitudinal partitions may be provided in the moulds. Where transverse partitions are used the intervening spaces may be filled with mastic, to seal the slots or perforations in the partitions. The end plates 53, Fig. 9 may be hinged to the side walls and have horizontal slots 52, a removable plate 55 having vertical slots 54 co-operating with the plate 53 to locate the wires. Cross-bars 56 being provided to secure the side plates and retain the plates 55. Intermediate anchorages or guides for the wires may be provided where the number or pattern of the wires differs from unit to unit along the line. Specifications 338,864, 338,934, [both in Class 87(ii)], 541,835, 554,693, [both in Group X], 572,385, 572,387, 572,388, 572.390 and 572,391, are referred to in the Provisional Specification.