Patent GB-704674-A (GB)
Title: A brickmaking machine for moulding sand-faced bricks by soft clay process
IPC: B28B13/02
Filed: 1950-12-07
Abstract: 704,674. Brick-making machines. BERRY, D. G. Dec. 7, 1950, No. 29988/50. Class 87 (2) Relates to brick-making machines in which clay is fed by a pugmill, the delivery. end of which has a double cam to force it through openings into sliding moulds, and provides improvements in machines of that type as described in Specification 259,656, [Class 87 (ii)]. The said improvements comprise means to increase the pressure on the clay forced into the moulds, safety means to relieve the presence of foreign bodies and means to give cleaning accessibility. In a machine as described in the above prior Specification the clay is fed from the pugmill 10 to a coaxial chamber 17 of larger diameter containing the extrusion cams 20 and the cams are of snail form and have trailing ends shaped so that they temporarily close the outlet to the moulds after forcing the clay therethrough, the'moulds 22 being advanced in procession by a reciprocating pusher 43. Two inclined compressor blades 27, 28 are furnished in addition to the usual pugmill blades to keep the chamber 17 tightly packed. Mechanism actuated from a pin 30 on a wheel 29 of the driving gear rocks a shaft 38 and so transmits an intermittent reciprocating movement to the mould-pushing member 43. The latter. is guided by the framework and runs on three wheels on a platform 50. In an emergency an eccentric strap 103 included in this mechanism can slip instead of transmitting the drive. The incoming moulds push the filled moulds under a scraper 54 which removes surplus clay before delivering them to rollers on which they can be reciprocated by hand to strike against stops 102 to loosen 'the clay. Before the moulds are placed in the machine they may be coated inside with sand which subsequently adheres to the clay to produce sandfaced bricks. If the scraper 54 strikes an obstruction such as a stone it can tilt against the action of a weight 61. A sliding bar 68, which reciprocates in front of the scraper to clean it, is actuated by linkage 86, 89 from a rock shaft 83 which is operated intermittently by a piston- and-tube mechanism 7 connected to the pin 30 on the wheel 29. According to the invention the chamber 17 houses, in addition to the cams 20, a pressure plate 115 and is fitted with cleaning doors 116; and the plate 21, in which are the openings for the clay, is fitted with safety doors 125. The plate 115, the object of which is to increase the pressure on the clay and ensure that it has a high density in the moulds, is mounted on a shaft 113, and an eccentric 105 on the pugmill shaft 18 operates, through a bell crank 107, a Slotted link coninected to a lever 112 on the pressure plate shaft 113, so that when the extrusion cams 20 revolve inside the chamber 17 the pressure plate 115 rises and falls in time with the cams. The safety doors 125 are hinged to the die plate 211 and are held closed by weights 126 .mounted on an arm 128 and acting through links 129, the presence of foreign bodies overcoming the weights and allowing the doors to open to free them. The cleaning doors 116 are secured by screws 'at the base of the chamber 17 and on both sides of it. The Specification mentions that machines of this type may be fitted with a friction-driven hoist, controlled by a brake, for hauling up clay wagons to feed day into the pugmill.