Patent GB-615754-A (GB)
Title: Improvements in or relating to finishing machines for extruded pipes and conduits ofclayware
IPC: B28B21/90
Filed: 1946-06-18
Abstract: 615,754. Moulding pipes. BOOTH, J. F. June 18, 1946. No. 18208. [Class 87 (ii)] Mechanism for finishing, without handling, pipes formed by the extrusion of clay in a press, comprises a movable support on to which the extruded pipes are fed in succession, and finishing tools to which the pipes are carried by the support and which are applied to one or both ends of the pipes, the finished pipes being carried to a delivery station by further movement of the support. The movable support comprises a rotatable member 171 and a main frame 14 in which is mounted a vertical shaft 13 on which the member 171 rotates, the frame 14 being itself slidable in a base plate 17 by the action of a piston in a cylinder 167. The member 171 has six radial saddles 161 adapted to hold the pipes by suction as described in Specification 615,753, for which purpose there are passages 28, in the arms of a spider 31, and a central bore 26 connected to a vacuum pump. The finishing is accomplished by tools rotated at a high speed, with a light pressure, by motors 76 and 77 mounted in slideways 71 and 72 and advanced and withdrawn by pistons 81 and 82 in hydraulic cylinders 78 and 79. As mentioned in Specification 615,752, the table of the press, as it approaches the limit of its extrusion movement, operates a valve which causes the piston to move in the cylinder 167. This slides the frame 14 towards the press and brings one of the saddles 161 into contact with the newly extruded pipe. The pipe presses on a stamp 35 and thereby receives a mark, and the pressure also operates a valve 34 and causes suction to be applied through a spring-loaded valve 33, held open, at this position of the member 171, by a cam 37. Further downward movement of the table reverses the valve controlling the piston in the cylinder 167 and the frame is retracted. The finishing operations on pipes already in the saddle 161 are initiated by a fringe of clay which exudes as a pipe is being formed in the press and which, as described in Specification 615,752, operates a switch, which energises a solenoid 59, so tipping a mercury switch 56 and closing a high tension circuit 54 whereby liquid is supplied to a hydraulic cylinder 43. The piston 44 of the cylinder 43 ends in a boss which carries a spring-loaded plunger 47 with a pin 48 which can enter one of six holes 42 in a disc 41 secured to the shaft 13, these holes being in a circular recess 49 in which the boss is guided. The movement of the piston 44 rotates the disc 41, and therefore the member 171, through one sixth of a revolution. An arm 137 attached to the piston 44 operates a valve 133 and supplies liquid to the cylinders 78 and 79, so applying the rotating finishing tools. The spider shape of the member 171 provides two finishing stations, at the first of which a trimming tool, in the form of a stretched wire, driven by the motor 76 through a belt 96, faces up the pipe to length. At the second station, at the socket end of the pipe, the fringe is removed by the tool 102, internal grooves are cut by the tool 103 and the base of the socket is radiused by the tool 104, while the other end of the pipe is operated on by a fixed radiussing tool 107 and a movable grooving tool 108. The tool 108 is mounted on one end of a lever 109 and can pass through the tool head 106. A bobbin 116, slidable on the shank of the tool head, has a cam portion 117 which engages with a roller 114 so that axial movement of the bobbin pivots the lever 109 through a linkage and moves the tool 108 into or out of engagement. The tool is operated by the piston 81 which first slides the motor, through the compression of a spring 124, and when the motor is brought up against a stop an extension 122 on the piston, through an adjustable stop 121, rocks a lever 118 and slides the bobbin 116 in the required direction. During the sliding movement of the motor 76 a rocking arm 143 is pivoted thereby, after a suitable delay occasioned by its head 142 resting in a slot, and so locks the member 171 in position by raising a shaft 64 into the hole 42 occupied by the pin 48, so locking the disc and, by pushing out the pin, releasing the piston 44. An arm 63 on the shaft 64 engages an arm 62 and tips the mercury switch 56 to the off position, with the result that the piston 44 is retracted and the pin 48 snaps into the next hole 42 of the disc ready for the next advance, and the valve 133 is reversed and so the tools are withdrawn, this last movement rocking the arm 143 and freeing the disc 41. Multiple pipes are dealt with by appropriately shaped saddles and motors having multiple heads, with external grooving effected by a cam-operated tool. The provisional specification mentions that the wire used in the trimming tool may be tautened by a ratchet and pawl, that the movable grooving tool, with its mechanism, may be used on both motors, and that the return movement of the plunger 47 may be damped by a needle valve in an oil circuit.