Patent GB-356779-A (GB)
Title: Improvements in and relating to extrusion processes for metal rods, tubes and the like
IPC: B21C31/00
Filed: 1930-04-07
Abstract: 356,779. Squirting. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.-(Scovill Manufacturing Co. ; Mill Street, Waterbury, Connecticut, U.S.A.) April 7, 1930, No. 10974. [Classes 83 (ii) and 83 (iv).] Making pipes; pipe end closing; shearing adjuncts.-A squirting press is constructed so that the feeding of a billet thereto causes the necessary movements of the ram and of the residue severing and removing device. For making tubes a turned and bored billet is fed, by hand or by feeding mechanism described in Specification 354,717, to a holder 84, Fig. 4, with spring-pressed retaining finger 85, which is advanced obliquely by hydraulic ram 88 to bring the billet in line with the press container. This comprises a sleeve 102, Fig. 7, mounted in a crosshead 107 having adjustable bearing pieces 110, 111 engaging the tie rods 108, 109. The crosshead 107 is constantly urged to the left by abutting rams 114, 115, Figs. 2 and 14, arranged in the main ram 170 and supplied with fluid through telescopic piping, but can be moved to the right by abutting rams 283. A perforated, dummy block 126, Fig. 10, is fed to a shoot 133, whence it falls into a holder 128 which is advanced by a piston rod 129 to position the block 126, which is held during transfer by a latch 137, between the billet and the extruding plunger. A mandrel 141, Fig. 14, movable in the main ram 170 is then advanced by an air-operated piston rod 149 to pass through and hold the block 126 and billet while the holders 84, 128 return. The mandrel 141 is carried by rod 145 and holder 147 transverselv movable on arcuate guides 143a of a crosshead 143, so that it can be removed as hereinafter described, when retracted by the rod 149, this having a small free movement relative to the head 143. The main ram 170 carries the extrusion adjustable plunger 201 which then forces the billet and block into the container 102 which is engaged by a removable die 223, Figs. 37, 38, in a holder 221 centred by radial set screws 222 in a casting 210. The mandrel is centred with respect to the die by a rod 227, Fig. 35, engaging both parts by coned faces and ball-jointed at 232 to a sleeve 231 pivoted to a withdrawing piston 240. The plunger 201 then upsets the billet, thus holding the mandrel central and the rod 227 is withdrawn. The rod 227 &c. is then swung aside about pivots 243 by a toothed segment 247, Fig. 36, and a rack 249 connected to pistons in constant and controlled pressure cylinders 234, 242 thereby swinging a guide tube 235 into position to receive the extruded tube. The ram 170 is first moved by low then by high pressure fluid as described in Specification 338,948, [Class 83 (iv), Metals, Work. ing], to extrude the metal. The mandrel is then withdrawn, the initial movement being assisted by hydraulic plungers acting on the crosshead 143. The portion of tube last extruded is then crushed, to form a point for threading through a drawing die, by two pairs of heads carried by piston rods 254, 264, Figs. 37, 38, of which the latter are first advanced by auxiliary pistons 278 to support the tube while the former indent it and withdraw, then the main pistons 265 act to complete the effect. The sprue is then cut off by a blade 268, operated by a piston 270, and the pistons 265 are withdrawn to release the tube. The container 102 is then withdrawn from the die, taking the sprue with it, and is arrested by adjustable stops when the stationary plunger 207. has pushed the block 126 and sprue so that this is just outside the container. A knife 289, Fig. 8, operated by a piston then wipes across the face of the container and knocks or cuts off the sprue which falls into a pocket 294. The plunger 201 is then advanced sufficiently to push out the block 126 which is received by a holder 300 which then returns to remove the sprue and bring the block 126 into line with a conduit 301, Fig. 12. A bore-trimming cutter is then advanced to push the block through the conduit 301 to trimming cutters 317 which arrest it until the bore is cleared and then trim it as it is advanced by a shoulder on the bore trimmer. Latches 315 prevent the block from returning with the bore-trimming cutter. The container 102 and plunger 201 are then withdrawn to their original positions, the guide tube 235 and rod 227, Fig. 35, are swung back to their original position and the cycle of operations repeated. After each operation the hot mandrel is replaced by a cool one by the device shown in Fig. 41. When the mandrel is in retracted position, the holder 147 is engaged by a hook 323 which is turned about a pivot 327 by a piston 341 to withdraw the holder as shown, the head 144 engaging a hook 352 which is moved to the right to pull the mandrel rod 145 into an empty chamber in a vertically movable housing 363. The housing is then moved to bring a cool mandrel rod and holder into correct horizontal plane to engage the hooks 352, 233, the former advancing the rod through its holder and then the latter returning the whole to the crosshead 143. The hot mandrel may be cooled by an air blast. In cooling position the head 144 of the mandrel rod is engaged by springs of a plug 346a by which it may be entirely withdrawn for replacement. The various pistons are moved by fluid pressure controlled by valves which are operated by air pressure controlled by valves operated by D.C. solenoids controlled by switches operated by A.C. solenoids controlled by switches operated by movement of parts of the machine and particularly by cams on drums which are oscillated by racks from the plunger 201 and container 102. All the controlling switches are first set in the correct position to start the cycle of operations, at the point where the cut off sprue is ready to be knocked off the block 126, by closing suitably connected switches by a hand-operated A.C. relay device. The machine is started by closing an A.C. switch which, acting through relays, admits water into cylinder 293, Fig. 8, thus advancing the slide 290 to knock off the sprue. The slide 290 in its movement closes a switch to cause the ram 201 to advance and each part in its movement similarly operates switches to effect some subsequent movement. Some of the switches such as 403, Fig. 61, are operated when the cam surface 405e passes in one direction as indicated by the arrow ; in the reverse direction co-operating inclines 405/ swing contact piece 405d out of the way. Switches are also arranged to arrest movement of some parts if other parts have not completed their necessary movement. The movement of the ram 201 is arrested during the preliminary compression of the billet, when the pressure of the actuating fluid has risen to a predetermined value, insufficient to cause extrusion, by a switch operated by a spring-loaded piston communicating with the pressure line. The hydraulic supply has low and high pressure relief valves, the former being put into connection with supply only during extrusion stroke when high pressure water is being used. The mandrel exchange mechanism may remain idle or by operating a. hand switch may be included in the automatic cycle of operations. A supply of hot billets as described in Specification 354,717 may similarly be included. Pilot lamps are employed to show the circuit conditions. In a modification unpierced billets are employed and in this case the mandrel centring tool is'omitted and the mandrel is operated by water instead of air pressure. Specification 338,946, [Class 83 (iv), Metals, Working], also is referred to.