Patent GB-700980-A (GB)
Title: Improvements in and relating to the manufacture of concrete and like pipes and hollow bodies
IPC: B28B21/26
Filed: 1950-05-08
Abstract: 700,980. Machines for casting pipes &c. MARTINEZ, H. Aug. 8, 1951 [May 8, 1950], No. 11442/50. Class 87 (2) In a machine for the manufacture of concrete pipes wherein concrete is radially dispersed within a stationary mould to form a lining therein of the required thickness the mould is supported on a table which can be swung about an offset pivot carried by a resiliently-supported frame, the table being raised and lowered by lever-operated crank gear arranged so that the lever passes beyond the dead centre immediately before the table is fully raised whereby the table and mould are locked in their raised positions during the moulding operation and until the lever is forcibly returned. The mould g, which is in two halves, hinged together at g' and held by a catch, is jammed between a plate d<2> and a table e by raising a frame f, on which the table is mounted by means of a hand-lever f<4> which rocks spring-loaded links f<1> over deadcentre position, adjustable link springs f<8> and guides f<5> being fitted. Bevelled edges g<4> at the top and bottom of the mould fit in recesses in the plate d<2> and table e to make it self-centring. The table e is pivoted to the frame f at e<2> so that, when the frame is lowered, the mould can be swung outwards. The plate d<2> has an aperture through which the material, e.g. semi-dry concrete. is fed into the mould from a loading tray d. A vertical shaft c is driven through bevel gearing from a horizontal shaft k which is in turn driven from a parallel shaft b through a two-speed gear K<3>, K<4>. The bevel wheel on the shaft c is keyed to a long key c<4> and the shaft is thus enabled to rise vertically. The upper part of the shaft c is threaded at c<5> and a half-nut m can be brought into engagement with the thread by a lever n<5>. A loose collar c<8> interposed between two fixed collars on the shaft has a projection c' which is engaged by an endless chain o which passes over an adjustable sprocket o<1> and a sprocket o<2> on the shaft of a handwheel o'. When a closed mould is in position the shaft c is lowered by the handwheel o<4>, through interaction of the chain o and collar c‹, till the bottom of the mould is closed by a disc on the lower end of the shaft c. The shaft carries vanes h secured to it just above the disc by nuts h<1> which pass through slots in the vanes to adjust the distance between the tips of the vanes. The half nut m is brought into engagement with the thread c<5> and the machine started. Semidry concrete is poured into the mould and dispersed by the revolving vanes h so that it forms a lining inside the mould the vanes rising with the shaft c until the collar c<6> strikes a lug m' on the nut m and disengages it, this being arranged to take place when the dies at the bottom of the shaft rises out of the mould. The frame f is lowered, the table e swung out. the mould halves undone and the pipe removed. To prevent the shaft c and its fittings descending by their own weight a brake block is provided in connection with the shaft on which the sprocket o<2> is fixed.