GB524409A - Improvements in or relating to dies - Google Patents

Abstract

524,409. Cupping; flanging. ARMSTRONG CORK CO. Jan. 30, 1939, No 3128. Convention date, July 13, 1938. [Class 83 (iv)] A die unit particularly for working sheet metal comprises a movable draw-ring or like in the base having direct fluid pressure below it to uniformly load it. The top dies comprise a cutting and holding down punch 8 surrounding a forming and ejecting die 10 all co-operating with bottom dies comprising a cutting-ring 36, a draw-ring 43 and a forming- die 39. The die 10 can be removed when holding back a spring pressed pin 15, a similar pin holding the lower die 39. Air pressure for ejection is supplied on top of the die 10 through passageways in a stop member 12, Fig. 8. The combined dies form a sub-press to be inserted and actuated mechanically by a main press as in Fig. 7, where, if the base 84 deflects too much, it actuates a switch 93 to stop the main ram. The dies can be easily changed for others of the same size but different shaped heads for bottle closures. A sheet fed between the dies is severed by a punch 8 acting against the ring 36. The blank is then clamped between the punch 8 and a draw ring 43 and as both move down, the disc' 3 cupped between the ejector dies 10 and former 39, air being continuously applied to the chamber 35 under the draw-ring 43, this pressure being gradually increased as drawing proceeds by the check valve 74 provided in the air line 72, which automatically limits the flow of fluid from the chamber 35 back to the source. When the punch 8 and die 10 ascend, the draw-ring 43 also ascends to normal position, air above it escaping through passageway 94. As the punch leaves the draw-ring air fed to the vacuum breaker feed 56 moves the blank awav from the top of the draw-ring 43 so that it is carried up within the punch 8 until stripper 59 removes the remaining skeleton 61 of the sheet from the punch. Air supplied to a central distributing chamber 24 and thence to chamber 11 of the ejector 10 to eject the cupped blank from within the punch 8, assisted by the spring pressed pin 20. The falling blank is blown by air jets 79, Fig. 6, to a container or conveyer. The sheet T is then moved to the right for a repeat operation. The air pressure supplied from a source S is turned on and off by a cam 65, Fig. 6, operated by the punch unit to open valve 64 supplying air through 23, 24 to the top of the sub-press, along with lubricating fluid from a pet-cock 69. Air is also supplied through pipe 70 reducing-valve 71 manually operated to vary the pressure through 45 to the draw-rings. A safety control 73 shuts down the press if the pressure drops below a predetermined minimum. A lubricating pet-cock supplies lubricant into the air pipe 45 for the lower part of the press.