GB1369112A - Movement or deep drawing of material - Google Patents

Abstract

1369112 Cupping WESTERN ELECTRIC CO Inc 8 Feb 1972 [10 Feb 1971] 5766/72 Heading B3Q Material in a sheet like blank is moved by a drag force which is exerted along the face of the blank by a viscous fluid. In the embodiments, which relate to deep drawing, the drag force is produced by a highly pressurized viscous fluid (e.g. silicone putty) directed to flow inwardly from the periphery of the blank. The pressure of fluid against the blank increases the ductility of the metal or other material of the blank, and the flow drags the blank inwardly towards a point where drawing pressure is applied. Shells of cylindrical or other form may be produced. In one form, Fig. 1, a die 47 is driven down by fluid pressure in a surrounding cylinder 44 to sever a blank 73 from sheet 72. The blank rests on an assembly of cylinders 6, 8, 10 which contains two annular pistons 11,19 and the drawing punch 28. The pistons and punch are operated,. through rods 12, 20, 29, by pistons 15, 22, 33 in a lower hydraulic cylinder block 37, the annular pistons being driven in opposite directions so that fluid driven upwardly by the outer annular piston 11 flows radially inwardly across the undersurface of the blank and downwardly against the inner annular piston 19 after passing through passages 65 containing non-return valves 66. A plastics pad 58 supports the top surface of the blank which is drawn through the die 47 by the punch 28 and beyond a stripper 59. Alternatively, or in addition to the stripper, a device for trimming the drawn shell 74 may be mounted above the die opening 53. Return passages 67 with one-way valves 68 are provided between the cylinders 6, 10. The punch 28 is raised with the outer piston 11. The pistons 11, 19 and punch 28 may be returned and a second working stroke performed. In a modification, Fig. 4, the viscosity of the layer of fluid 62 in contact with the top of cylinder 80 is varied by an electrically heated plate 77 supported by insulation 75. In another form, Fig. 6, the fluid chamber bounded by the underside of the blank 73 is divided by a rib 107 into two annular zones 108, 109. Fluid is circulated radially inwardly of the inner zone before passing into the outer zone so that the overall pressure is greater in the inner zone. During the drawing stroke the inner annular piston 94 rises pumping fluid 62, through axial passages 110, 111, into the inner zone 108 from which it passes, through axial and radial passages 114, 115, 116, into the outer zone 109 for eventual discharge, through axial passages 112, into the outer cylinder 89. Articles of irregular form, Fig. 10 (not shown), may be produced using drag paths of different lengths between entry and exit holes (120, 121) for the fluid pressurizing the blank. Both sides of the blank may be engaged by pressurizing fluid, Fig. 11 (not shown), the top and bottom parts of the apparatus being similar to the bottom part of the apparatus of Fig. 1. Electrical heaters may also be used on both sides of the blank, Fig. 13 (not shown), or both sides may be divided into two annular zones of different average pressure, Fig. 14 (not shown).