Patent GB-873743-A (GB)
Title: Improvements in or relating to block making machines
IPC: B28B3/08
Filed: 1957-09-25
Abstract: 873,743. Casting concrete blocks. COLLENS, P. P. Sept. 23, 1958 [Sept. 25, 1957], No. 30083/57. Class 87(2). A machine for the manufacture of hollow concrete building blocks comprises a fixed mould, a core or cores movable into the mould to define with the wall of the mould a jacketlike cavity, or cavities, means for feeding a concrete mix into the cavity or cavities in the mould and two oppositely acting hydraulic rams adapted to apply pressure from opposite sides of the mould on the concrete mix within the mould to compress the mix into a concrete block. The concrete is raised in a bucket 5 to a position above a feed hopper, 4, the bucket 5 having rollers 12, 13 and running on rails 10, 11 which follow tracks, as shown in Fig. 2, such that, at the top, the bucket tips its contents into the feed hopper. At the end of a cycle of operations a box 6, open at top and bottom, is below the hopper 4 with which its open top is in communication while its bottom is covered by a plate 14a. The box 6, charged with concrete, is moved, by hydraulic pressure in a cylinder 17, above the moulds 7. The movements of the box 6 are caused, through a lever 13b, to move arms 13 in the hopper and so agitate the concrete. Electric rotary vibrators 19, 20 are set in operation, assisting the concrete to drop from the box 6 into the moulds and consolidating the concrete when it is in the moulds. Mounted on the side of the box 6 which is nearest the moulds 7 is a container with four compartments 38 (equal to the number of moulds), Fig. 4, each of which contains a stack of pallets. The bottom pallet of a stack rests on the ends of pins 40 and the pallet above it is supported by pins 39 which are pointed and enter holes in the edges of the pallet, on which also rests the remainder of the stack. As the box 6 moves above the mould a ratchet wheel 49 engages a fixed pin and is thereby rotated through a short distance, so operating a cam which moves apart sliding plates 41 on which the pins 39 are carried and are so disengaged, whereupon the stack of pallets drops on to the pins 40, the pins 39 then being returned by the action of a spring 45. On the return movement of the box 6 the pallet magazine moves above the mould and another pair of sliding plates is similarly actuated and the pins 40 are retracted whereupon the bottom pallet drops into the mould. The upper ram 8 moves down through the position previously occupied by the box 6 and pressing members 27a compress the concrete. The lower ram then ascends, its compressing members 27a passing through apertures in a floating plate 18, which carries cores 21 by which hollows are moulded in the blocks, and further compressing the concrete against the stationary upper ram. The upper ram then ascends more quickly than the still ascending lower ram and the compressed block is ejected by the last part of the movenemt of the lower ram. A hydraulic ram then moves an arm 35 of a parallel linkage supporting a platform 34 to bring the platform beneath the pallet supporting the blocks, and the lower ram 9 then moves downwards again. The linkage is then operated to move the platform away from the mould to a position (shown in broken lines in Fig 2) in which the pallets, carrying the blocks, are transferred to a conveyer 33. Alternatively the pallets may be pushed on to a platform by the pallet magazine and the platform lowered by the movement of the box 6 transmitted through linkage. The hydraulic rams 8 and 9, the piston and cylinder arrangement 16, 17, the vibrators 19 and the transfer platform are hydraulically operated and their sequence of operation is determined by an electrical timing mechanism. The hydraulic circuits are not shown but the sequence of the various operating parts is controlled by a mechanical control drum which operates to open and close a series of hydraulic valves which in turn operate to control the main hydraulic valves in the required sequences.