GB1207190A - Improvements in or relating to the manufacture of concrete elements - Google Patents

Abstract

1,207,190. Moulding concrete. DANSK SPAENDBETON A.S. 8 Dec., 1967 [9 Dec., 1966], No. 55931/67. Heading B5A. In casting concrete elements in a mould provided with parallel cores which are withdrawn from the partially set concrete one, or a few, at a time, those cores which are, at any instant, not being withdrawn absorb the reaction of the force necessary to withdraw the said one or few cores. An elongated mould 1, 2 has longitudinally extending cores 3 connected by rods 5 to pistons 4 of an assembly of hydraulic cylinders A-G carried by a wheeled structure mounted on the mould. The rear ends of the cylinders are interconnected by a pipe 6 and the front ends are connected by pipes 7 to a fluid distribution valve 8 supplied with fluid from a tank 11 by a pump 9. A return pipe 13, and a by-pass valve 14 and pipe 15 are provided. In the position of the cores shown, the valve 8 is operated, e.g. by a driven cam-shaft, to direct fluid to cylinder D via pipe 7, while for the other cylinders unobstructed passage exists through the other pipes 7 and valve 8 for fluid to return to the tank. Thus, the piston in cylinder D and its associated core is moved longitudinally and transfer of fluid from this cylinder to the others via pipe 6 produces a force on the rear of the other pistons and, since the cores associated therewith are held in the concrete, the assembly of cylinders is moved a further distance producing an additional advance of the said associated core. By feeding pressure fluid to different cylinders, in turn, the cores are withdrawn in stages from the cast concrete.