1,088,852. Billet piercing. LOEWY ENGINEERING CO. Ltd. Jan. 15, 1965 [Feb. 7, 1964], No. 5348/64. Heading B3H. A hydraulic piercing press comprises a stationary base 10 supporting a holder 11 for the workpiece B, a piercing tool 42 mounted on a movable upper crosshead 40 connected by columns 43, 44 to a lower movable crosshead 30, a movable back up crosshead 20, disposed between the base and the lower crosshead 30 and carrying a back-up stem 16 for supporting the workpiece during piercing, and a hydraulic drive 31, 32 for the piercing tool arranged partly on the back-up crosshead 20 and partly on the lower crosshead 30. The billet holder 11 is slidable transversely on rails 12, 13 from a charging position into the press axis. Billet B is first upset by a tool 52 mounted on an intermediate crosshead 50 which moves initially with the piercing tool due to the insertion of hydraulically operated gags 53 actuated by hydraulic rams (54), Fig. 2 (not shown). The gags are then withdrawn and the piercing tool 42 is pressed through the billet by pressure liquid supplied to four cylinders 31, carried by the lower crosshead 30, through hollow pistons 32 carried by the back-up crosshead 20; this ensures that the back-up stem 16 is pressed upwardly into surrounding die 15 during piercing. Finally connectors 45 on the moving columns 43 engage sleeves 49 abutting the back-up crosshead 20 to lower it thus removing the back-up stem and allowing the tool 42 to punch out the remaining web of billet metal. The tool 42 is then raised by retracting rams 37, 38 whilst the billet is held down by tool 52 under pressure from two hydraulic rams 56. Finally the connectors 45 engage the crosshead 50 to raise the tool 52; this is assisted by pressurization of cylinders 58. Billet holder is then moved to an inoperative position where the pierced billet is ejected, the holder 11 cleaned and lubricated, and a new billet inserted. The back-up crosshead 20 may be raised independently by hydraulic rams 23, 24, Fig. 4 (not shown), or it may be lowered against stops 29 by hydraulic rams 26, 27.
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