BODY'S PARTS DRAW-FORMING STAMP Russian patent published in 1997 - IPC

FIELD: tension of different parts from sheet billets. SUBSTANCE: stamp has punch, die with stretching ribs having rounded edge on working end and pressure member with stretching rib receiving recesses. Recesses have inclined side walls extending tangentially of radial portions of rib to pressure member at an angle of 45 deg. Minimum tangential gap between side surfaces of recesses and radial portions of ribs is equal to initial thickness of billet, with positive sheet thickness allowance being taken into consideration. Gap between die and pressure member pressure surfaces is equal to 1.2-1.5 of billet thickness. Recesses may be made triangular or trapezium-shaped. EFFECT: reduced consumption of material by reduced allowances for pressure surfaces and billet braking, wider operational capabilities and improved quality of parts. 3 cl, 3 dwg