GB503603A - Improvements relating to the moulding of concrete - Google Patents

Abstract

503,603. Moulding concrete blocks. RUEGG, A. E. Sept. 6, 1937, Nos. 24337 and 29102. [Class 87 (ii)] [Also in Group X] Concrete articles, such as arcuate blocks for tunnel linings, are moulded by applying pressure to the concrete by one or more expandible cores and also subjecting the concrete to vibration and suction. The mould comprises arcuate steel walls 6, 7 closed by end plates 8. Cores 5 are carried by the inner wall 6 and are shaped so as to enable the mould to be taken apart. The mould sections are held tightly together by bolts 15 and bridging pieces 16 and three units may be arranged one above another with a single outer wall and three separate inner walls. The concrete is introduced through valves 18. The cores 5 are of wood surrounded by a rubber envelope 26 which is expanded by compressed air through pipes 28 to compress the concrete. The mould is lined with metal or wooden staves 19 containing drainage channels 20 which are connected to a vacuum pump by pipes 21. Vibration is applied by applying a vibrator to a spring pressed pin 24 which contacts with a steel band 23 in a recess in the staves 19. The concrete may be heated by steam or hot air. Grouting plugs 54 with wood fillers may be provided. The block, as shown in Fig. 7, may be reinforced with main bars 32, 53 and transverse rods 33 and holes 34 are provided for bolting the sections together, which holes may be flared to facilitate introduction of the bolts. Marks are formed on the outside of the block to indicate the position of the holes. In a modification, Fig. 10, the mould has a curved bottom plate 35 stiffened by ribs 36, 37 and a top plate 38 of channel section which also forms the sides of the mould. The ends are closed by plates 42. Specification 486,452 is referred to.