Patent GB-615752-A (GB)
Title: Improvements in or relating to presses for pipes and conduits of clayware
IPC: B28B21/52
Filed: 1946-06-18
Abstract: 615,752. Moulding clay pipes, &c. BOOTH, J. F. June 18, 1946. No. 18206. [Class 87 (ii)] In a moulding press for forming pipes &c. from clay, a fringe 48 of clay is allowed to exude between the end of a mould 28 and the face of a table 49 for the time being locked against the end of the mould, and means responsive to the exudation of the said fringe are provided for effecting release of the table and extrusion of the clay without manual control. The press is power-driven through a clutch 17 from which motion is transmitted through gearing to a vertical shaft carrying a worm 36. The table 49 is slidable on pillars 31, 32 and has a central shaft 56 extending below floor level. The locking device to hold the table against the end of the mould comprises a pair of toggle links 68 with pins arranged to ride in curved slots 71 in a pair of frames 62, the upper link bearing against the head 61 of the shaft 56. Underneath is a grabbing device consisting of a pair of hooked members 73 pivoted to a crosshead 74, with pins bearing in cam slots 77 in a pair of frames 78, the slots being so shaped that when the crosshead 74 moves downwards the hook members 73 first move towards one another and grab the head 61 and then pull it downwards. A cutter bow 131, containing a cutting wire 132, is pivoted on the pillar 31 and when operated swings so that the wire passes between the base of the mould and a die 43 (the die having dropped) with the assistance of springs 133, on to the heads 42 of studs 41 on the commencement of the downward movement of the table 49. A spray nozzle 151 is connected by a conduit 152 to an oil injector 149 operated by an air valve 147, and is connected by a conduit 153 to a valve 148 supplying compressed air, so that oil and compressed air can form a spray which issues from the nozzle 151 on to the moulding surfaces of the die 43 and a core 46. When the clutch 17 is engaged the worm 36 urges the clay into the mould and causes it to extrude through an annular throat 39 and fill up the space between the core 46 and the die 43 so as to form the socket portion 82 of the pipe, and then to exude from recesses 47 in the flange 44 to form the fringe 48, continuing until a portion of the fringe strikes a switch 83, which can be adjusted to respond to varying sizes of fringe. The switch 83, wired in a low voltage circuit, operates a second switch 86 in a high voltage circuit which operates a solenoid 87, which in turn moves a lever 88, 89, the lower arm 88 of which operates an air valve 92 which causes compressed air to enter a cylinder 64 and retract the piston therein to unlock the toggle 68. The table, so released, is forced downwards by the extruding clay and the body portion of the pipe is thus formed. The table descends until a roller 102 mounted on it depresses an arm 104 linked to an arm 109 which operates an air valve 110 and causes the piston to move in an air cylinder 117 so as to rock the lever 19 and disengage the clutch 17 and stop the extrusion. The cutter bow 131 is then actuated by an air cylinder 124 supplied through a rotary valve 123 which is operated by a roller 119 when the table nears the limit of its extrusion movement, and at the same time another roller 136 strikes a slipper 138 and causes air to be supplied to the cylinder 81 so that its piston 79 moves downwards and draws down the crosshead 74. The extruded pipe is thus cut and then lowered further, and to allow time for its removal the shaft 56 has a reduced portion 59 near its end over which the hooks 73 move idly at the beginning of the return stroke. Also, when the table 49 reaches the limit of its extrusion movement, a roller 163 engages a slipper 164 and sets in motion the mechanism for transferring the extruded pipe as described in Specification 615,753. A finishing machine, as described in Specification 615,754, may also have its operation co-ordinated with that of the press. The return stroke of the piston 79 follows the springing back of the slipper 138 when clear of the roller 136, and starts the ascent of the table, which continues by the action of counterweights 51; the rollers 136 and 119 having no operative action when moving upwards. As the table approaches the mould the valves 147 and 148 are opened by a roller 146 having a positive action only in the upward direction, and the oil spray is thus operated. When the table reaches its topmost position the roller 97 strikes the upper arm of the lever 88, 89 and causes it to reverse the valve 92, which brings into operation the locking device and rams the table against the mould, and the roller 102 strikes the arm 109 which reverses the air valve 110 and causes the re-engagement of the clutch and thus the re-commencement of the cycle of operations. The Provisional Specification mentions that the operating means may be hydraulic.