Patent GB-808051-A (GB)
Title: Methods and apparatus for making building slabs
IPC: B28B7/18
Filed: 1957-01-25
Abstract: 808,051. Casting building slabs. COOK, J. H. Jan. 25, 1957,No. 2776/57. Class 87(2). [Also in Group X] Plaster is poured into a mould in which are contractile cores and allowed to set, the mould is opened, the cores are contracted, the bottom of the mould is withdrawn carrying the cast slab, the slab is raised off the bottom of the mould and carried away, the bottom of the mould is replaced, the cores expanded, the mould closed and the cycle of operations repeated. General Arrangement. Moulds 20 are disposed on a turntable 21 and mixer 26 or another turntable 24 above the turntable 21 and centrally, or to one side of it, as shown in full and dotted lines, Fig. 1. While one mixer is being cleaned and recharged with a measured quantity of water, another, previously so treated, is charged through a shoot 27 with a measured quantity of plaster from a container 22. The turntable 24 is rotated and the charged mixer brought into position where the mixed plaster is transferred through a pipe 30 to a mould 20, which is then moved away as the turntable 21 is rotated. After the turntable has moved through several stages, the plaster setting all the time, the mould reaches a station where it is opened and the slab is withdrawn and removed on a roller conveyer (another mould being meanwhile filled) ; then the mould is cleaned and adjusted as the turntable brings it back to its charging position. Mixer. A shaft 35 from which a series of paddle arms 40, Fig. 3, project in a diametral plane is rotated by a handle 39, or by an electric motor 52, through bevel gearing 38 and the paddle arms pass between complementary, stationray paddle arms 41 projecting from the inside of the casing 31. In the bottom is an outlet port 42 communicating with a feed pipe 43 in which a plunger 44 is reciprocable, being advanced to close the port 42 while mixing is taking place. The plunger is withdrawn, and then returned to drive the mixture, that has poured in front of it, into a downpipe 46 leading to a mould. One or several strokes may be necessary to fill the mould, according to the size of the feed pipe and plunger. In a modification, Fig. 6, epicylic gearing 49, 50, 51 causes a rotating shaft 54 to circle around a central conduit 56 in which a plunger 58 is vertically reciprocable to feed mixture through a pipe 59 which enters through ports 57. Another modification combines the feed plunger arrangement of Fig. 6 with the paddle arrangement of Fig. 3. Mould opening device. Figs. 11, 12. Each mould comprises two cavities divided by a central partition 62. The outer side walls 61, of sheet metal faced with synthetic resin, are strengthened by uprights 68 which are pivotally mounted at their lower ends. A bracket 73 rises from the partition 62 and provides a pivot 77 for an arm 74 which has a handbar 75, by which it can be swung across the top of the mould, and at the other end a tail piece 76. The side walls 61 have upward extensions 78 which are linked by rods 79 one to the arm 74 and the other to the tail piece 76. Each top mould closure 67 is carried by a bar 84 which is pivoted to the upright 73 at 85 and connected by a drop link 86 to the adjacent wall extension 78. When the arm 74 is swung across from the full to the dotted line position the side walls 61 swing outwards and the top closures 67 swing upwards. One end of the mould is closed by a member which includes mechanism for expanding and contracting the cores and the other end is constructed as a pair of gates 108, Fig. 11, one for each mould cavity, which are raised by a handle 111 and swung upwards, being hinged to a bar 109, thus opening the end of the mould. Rods 107, by which the cores are expanded, normally pass through the gates 108, and to enable the gates to be first moved axially to clear them the holder 110 for the bar 109 is slotted. The gates 108 stop short of the bottom, to allow clearance for the floor of the mould to slide in and out, and the space is closed by doors 112 hinged on vertical pivots 113 and held closed by catches 114. Expansible Cores. A reinforced rubber skin 106, Fig. 21, encloses an assembly comprising a Y-sectioned rod 130 and capping members 133 over the ends of the limbs 132, with which they are connected by a plurality of pins 134. Inclined slots 135 are spaced along the length of each limb 132, Fig. 20, and the ends of the capping members 133 abut plates which abut in turn, at one end, a channel 136, Fig. 18, and, at the other end, one of the gates 108 ; thus the capping members cannot move axially and when the rod 130 is so moved they move outwards and expand the skin 106. Axial movement of the rods 130 for all the cores is accomplished simultaneously by toggles 140 operated by a lever 142 and interconnected by chains 141. Springs 145 exert a pre-tension and ensure that the skins 106 are held around their capping members. Contour inserts. A member 120 shaped to give a required contour to the face of the casking may be attached to the wall 61 of the mould, Fig. 12. The mould is enlarged to compensate for the thickness of the member 120 by moving out brackets 121, from which the wall-bracing upright 68 are pivoted by means of nut and bolt adjustments 83, and the mould opening linkage is adapted by extensions 123 on the push rods 79 and extensions 125 on the bars 84, and wider parts are substituted for the closures 67 and floor members 66 forming the bottom of the mould. Nut and bolt adjustments 81, at the pivots 80 between the arms 78 and the push rods 79, allow vertical positioning of the walls 61. Contour plates 95 also extend along the floor members 66 to shape the edge of the cast slabs. Removal of Casting. When the cores have been collapsed, the floor members 66 are withdrawn through the opened end of the mould by a chain 88, Fig. 15, passing round sprockets 90, one of which is rotated, through another chain 91, by a handle 92. The travel is limited by a stop 94, when slots 101 across the tops of the members 66, and spaced along them, lie opposite bearing blocks 102 which are carried by longitudinal beams 96, Fig. 16. Rods 103 are then inserted through the beams 96 and the bearing blocks 102 to pass through the slots 101, extending across the bottoms of the moulds beneath the contour plates 95. The beams 96 are swiveled to fixed beams 97 by links 98, the end pair of which are extended to form a handle 99 by the operation of which the beams 96 lift the contour plates 95, carrying the cast slabs, from the floor members 66, after which the contour plates, with the slabs, are run off over the rods 103 on to a delivery roller conveyer.