Patent GB-1109722-A (GB)
Title: Apparatus for deep drawing metal
IPC: B21D24/00
Filed: 1965-04-22
Abstract: 1,109,722. Capping-presses; making hollow-ware. S.T.D. SERVICES Ltd. 22 April, 1965 [23 April, 1964], No. 16926/65. Headings B3A and B3Q. A deep drawing press for making cylindrical and other cans, tubes, pressure vessels &c. comprises drawing dies 106, 110, 112, Figs. 17, 18, through which a flat workpiece B is drawn by a set of telescoped punches 70, 72, 74. A pressure plate 102, bearing on the work-margin as the work is drawn through the first die 106, co-operates with a die-ring 104 to blank flat work from strip. An ironing die 114 is also provided, and a stripper 116. The dies are mounted on stationary plates 86, 88, 90, 92 and the punches on movable plates 28, 30, 32, guide rods 24 passing through the plates. The press-ram (150), Fig. 3 (not shown), is attached to the plate 28 and may be driven, through hydraulic vibrators, by a gear pump, or by one or more axial-piston pumps producing vibrations of lower frequency, the vibrations facilitating the drawing operation. An accumulator may be used to reduce the magnitude of the vibrations. Initially the punch-plates 28, 30, 32 move together, being connected by hydraulic cushions (52, 54, 56), Fig. 14 (not shown), the cylinders of which are connected to one of the plates and the pistons to another and providing a fluid outlet controlled by valves, Figs. 19 and 20 (not shown), mounted on the plates. Operation.-Advance of the pressure and blanking plate 34 is terminated by stops 40 engaging the die-plate 86 and the first drawing stage then follows, Fig. 16 (not shown), with the three punches moving together, escape of fluid from the hydraulic cushions 68 acting between plates 32, 34 allowing the plates 28, 30, 32 to approach plate 34. Movement of plate 32 is stopped by stops 40 on plate 34 which has an abutment 154 for opening a valve 142 in the circuit of the hydraulic cushions 54 between plates 30, 32. This enables the cushions 54 to close and the plate 30 to approach plate 32 for the first re-drawing stage (Fig. 17). At the end of this stage, similar stops 40 and an abutment 154 on the plate 32 arrest the plate 30 and open the hydraulic cushions 52 between plates 28, 30 to permit movement of plate 28 towards plate 30 for the second re-drawing operation and the ironing operation through die 114 (Fig. 18). Rods 42 interconnecting the movable plates 28, 30, 32, 34, pull them apart when the ram is returned. Shims may be used beneath heads on the rods 42 and beneath the stops 40. The flow of fluid from the cushions may be regulated by a loading screw (144), Fig. 19 (not shown), an overload release also being provided. The end of the work may be embossed by the inner punch 70 and a die carried by plate 92 or the end plate 18. Cans of length to diameter ratio up to 15 to 1 may be produced when one or more ironing stages follow the last re-drawing stage. To avoid cold-setting adjustments, the punches are preheated and maintained at the desired temperature by an electric heater (120), Fig. 3 (not shown). Reduction percentages and speeds are specified. In a modification, Fig. 24, (not shown), three sets of telescoping punches 70, 72, 74 are provided. Reference is also made to using a single set of five telescoped punches for effecting a drawing operation, four re-drawing and an ironing operation, in which latter the thickness is reduced from 0À04 to 0À027 inch.