GB859014A - Improvements in or relating to pressing tools - Google Patents

Abstract

859,014. Extruding; forging. LOEWY ENGINEERING CO. Ltd. Aug. 29, 1957, No. 27204/57. Class 83 (4). A locking-device for securing a press-tool 15 in its socket-shaped holder 11 comprises a number of plungers 22 movable in the holder by pressure means towards and away from the tool in a substantially radial direction and adapted to engage the tool and secure it in the holder. The device is described for use in an extrusion press wherein the main press ram 10 has bolted thereto a cylindrical holder 11 for receiving the pressing stem 15 which has an enlarged head 14 with splines 14A, a groove 19 and an end flange 18. Within the holder a resiliently mounted bearing 31, biased to the right by Belville washers 32, has splines complementary to those on the stem head which is first passed through the bearing splines into the holder and then rotated. The plungers 22 are advanced by pressure fluid supplied by a pump 68 from a reservoir 69 through valve 70 and duct 28 to the front of a fixed piston 23 disposed within a bore in each plunger. An indentation 30 in each plunger thus engages over the flange 18 of the pressing stem, Fig. 2 (not shown), and presses the latter firmly against a thrust-block 13. The plungers are retracted by pressure fluid admitted through valve 71 and duct 27 to the top side of piston 23 and thereafter the fluid is admitted through valve 74 to at least one chamber 35 containing piston 36 which moves bearing 31 to the left against the Belville washers to release pressure on the splines and allow the stem to be rotated and then removed. The valves 70, 71, 74 &c. may be operated manually or by an automatic servomotor control means. In an alternative embodiment, Fig. 4 (not shown), the bearing 39 is rotatable instead of the stem. In other embodiments, the splines are omitted and the bearing 31 has a plain bore, Figs. 5, 6 (not shown), or the enlarged head of the stem is detachable therefrom, Figs. 7, 8 (not shown). In a further embodiment, Fig. 9, the plungers 22 are pressed inwardly by springs 60 and are retracted by pressure fluid admitted through a conduit 63. Upon retraction a port 65 is opened and the pressure fluid passes through pipe 66 to act on the piston 36. The plungers 22 may alternatively be operated by eccentrics or toggles. A detachable lifting-gear 57, Fig. 7 (not shown), may be provided for the pressing stem. The invention may also be used in a forging, piercing or drawing press.