GB791625A - Improvements in apparatus for moulding concrete and like blocks - Google Patents

Abstract

791,625. Concrete block moulding machines. WELDING INDUSTRIES, Ltd. Feb. 10, 1956 [Feb. 15, 1955], No. 4496/55. Class 87(2). A concrete block moulding machine is movable from one position to another over a casting bed and comprises an open-bottomed mould box movable between a lowered position for moulding blocks on the bed and a raised position clear of the blocks and a power unit incorporating winch means for controlling the vertical displacement of the mould. The mould box 7, divided into compartments corresponding in length and breadth to the size-of block to be moulded and open at the top and bottom, is fitted in a carrier frame 6 vertically movable between pillars 3, and in its bottom position it rests on the casting bed on rubber feet 8. Above the mould box carrier frame 6 is a beam 14 from which tamper plates 15 depend and which is also vertically movable between the pillars 3. The ends of the tamper beam 14 are suspended by wire ropes 44, one of which is guided by pulleys 45, 46 to a drum 40 and the other by a pulley 46a and otlier pulleys (not shown) to the same drum, the ends being so attached to the drum that both are wound or unwound together as the drum is rotated. Ropes 31 similarly rise from each end of the mould box carrier frame 6 and are led by guide pulleys 32, 32a to a winch drum 30 and are attached thereto in a similar manner to that for the drum 40 so that rotation of the drum to wind up the frame 6 gives an even pull at both ends and the frame rises without tilting. The drum 30 is fast on a winch shaft 28 but the drum 40 is free on that shaft. To lower the tamper beam 4 a crank handle 50 is turned and held, so rotating a shaft 48 enough to disengage a pawl 43 from a ratchet wheel 41 secured to one outer face flange of the drum 40, to the other outer face flange of which a brake drum 42 is secured. One end of the brake band 51 is attached to the shaft 48 in such a manner that the brake can be applied or released by manipulation of the crank handle ; thus, when the ratchet is released the drum 40 is held only by the brake band and the lowering of the tamper beam is controlled by the crank handle. The winch shaft 28 is driven by a motor 24 through a chain 25 and sprockets 26, 27. A magnetic brake 33 acts on the main motor shaft. Assuming the frame 6 and beam 14 are in their bottom positions, an operating handle 36 is lowered. The action operates a switch 37 and the motor 24 rotates the winch drum 30 to raise the frame 6 and the beam 14. When a plate 38 on the beam 14 strikes the bottom of a knock-out column 39 thus column raises the handle 36 and switches off the motor. The drum 40 is rotated back again by a spring in the brake drum 42 and when the ropes 44 are re-wound the pawl 43 re-engages the ratchet and the beam 14, with its tamper plates 15, is held up, but the mould box carrier frame 6 descends again under its own weight. A shaft 9, mounted alongside the mould box carrier frame 6, carries eccentric blocks 10 and, when driven through a belt and pulley by a motor 11, vibrates the mould. A shaft 17 mounted alongside the tamper carrier beam 14 carries eccentric blocks 18 and when driven by a motor 19 vibrates the tamper plates. The motors 11, 19 are controlled by a switch box 21. In operation, the chassis 1, which has swivelling wheels 2, is positioned over the casting bed with the frame 6 lowered and the beam 14 raised. Aggregate is then fed from a hopper-like loading tray 13 into the mould compartments. The beam 14 is then lowered by operation of the crank handle 50 and the tamper plates rest on the top of the material in the mould compartments, which is compacted by vibration due to the motors 11 and 19 being actuated at the same time. When the moulding operation is completed the handle 36 is depressed and the mould box is lifted clear of the moulded blocks which are left standing on the casting bed. The chassis is wheeled to a fresh moulding position and the mould box carrier frame is lowered while the tamper carrier beam remains in its raised position. The two are retained in these positions by the magnetic brake 33 which is controlled by limit switches 34, 35, closed respectively by the raised operating handle 36 and the lowered mould box carrier frame 6. A limit switch 53 is installed at the bottom of each pillar 3 and both are closed only when the beam 14 is level, a condition thus shown by a lamp 54.