Patent GB-1195543-A (GB)
Title: Apparatus for Drawing Sheet Metal
IPC: B21D24/00
Filed: 1967-07-18
Abstract: 1,195,543. Cupping. S. T. D. SERVICES Ltd. 18 July, 1967 [18 July, 1966], No.32960/67. Headings B3A and B3Q. Apparatus for deep drawing cans &c. from sheet metal comprises at least two axially aligned punches and at least two axially aligned and separate dies, the punches being in telescoping relationship and sequentially movable relatively to each other and to the dies, one of the punches having an associated radially extending surface against which fluid pressure is directed to advance the punch relatively to the other punch or punches, and means against which a force may be directed to move another of the punches relatively to the dies. As shown, there are ten units 16 each including a casing 24 housing four telescopic members 62, 64, 66, 68 which carry respectively, a blanking punch 166, a drawing punch 128, a re-drawing punch 132 and a second re-drawing and ironing punch 134 which also co-operates with an embossing punch 150 for forming the end of the can. The punches are extended by pressure fluid supplied through central core members 28 to spaces 74, 76, 78, 80, Fig. 11B, at the ends of the top, smaller sections 62<SP>1</SP> ,  64<SP>1</SP>, 66<SP>1</SP>, 68<SP>1</SP> of the members 62-68, and are retracted by fluid supplied beneath a surface 98 on member 68. Blank and die holders.-Resilient pads 174, 210, 220, Fig. 7, are disposed above the blanking punch 166 and beneath the re-drawing dies 208, 214 so that after the blanking operation the blanking punch clamps the blank resiliently against the drawing die 194 during the drawing operation, and the drawing punches 128, 132, 134 operate in a similar manner during redrawing through the dies 208, 214. Stop-screws 94 on a flange 82 of the outer telescopic member 62 co-operate with a hold-down 182 for the sheet 22 being blanked; similar stop-screws are carried by projections 84 on member 84 and project through slots in member 86 to cooperate with fixed abutments 270. Further stop-screws 94 are carried by member 66 and co-operate with projections 84. Strippers; blanks transferring.-After the cans have been shaped against the lower punches 150, a plate 152 carrying the punches is moved laterally by a fluid-pressure cylinder to align holes in the plate with pivoted strippers 236 beneath the lower dies so that cans stripped from the rising punches fall into shoots 156 leading to a conveyer 158. Beds and framings.-Plates 18, 142, 144, 146 supporting the telescopic units and the dies are supported from a base 148 on replaceable channel-shaped spacers 258 embracing posts 260. An hydraulic control system is used, Fig. 16 (not shown), providing sequential introduction of fluid into the chambers 74, 76, 78, 80 under the control of valves which are operated by an increase in pressure caused when the telescopic elements are arrested by the stops 82, 84, 86. At the end of a stroke, punches 150 engage pads 244 and the increase in pressure in chamber 80 may be used to reduce the pressure on the elements 62, 64, 66, 68 so that they may be raised by fluid acting against the surface 98. Alternatively, a limit-switch actuated by the punches 150 may initiate their return and index the plate 152. During retraction, the stop 86 actuates a limit switch for operating a feed for the strip stock and a time-delay relay which initiates return of the plate 152. Specification 1,109,722 is referred to.