Method of producing shells of complex configuration

Claim 1

THE METHOD OF MANUFACTURING A STEEL SHELL HAVING AN OPENING WHICH IS DEFINED BY THE EDGE OF ONE SIDE WALL OF THE SHELL AND BY AN INWARDLY BENT FLANGE WHICH IS INTEGRAL WITH THE OTHER THREE SIDE WALLS OF THE SHELL, COMPRISING THE STEPS OF, DRAWING A BLANKET SHAPE TO A FORM HAVING AN OPENING GENERALLY OF EQUAL SIZE TO THE OPENING OF THE SHELL TO BE PRODUCED BY THIS METHOD, AND HAVING A FRONT WALL SUBSTANTIALLY SHORTER THAN THE BACK WALL, SAID FRONT AND BACK WALLS BEING INTEGRAL WITH A BOTTOM WALL AND TWO SIDE WALLS TO DEFINE A DRAWN SHELL HAVING SUBSTANTIALLY GREATER DEPTH AT ITS BACK THAN AT ITS FRONT END, SECURING SAID DRAWN SHELL IN A DIE, APPLYING HYDRAULIC PRESSURE TO THE INSIDE OF SAID DRAWN SHELL, APPLYING EXTERNAL PRESSURE TO THE BOTTOM WALL OF SAID DRAWN SHELL BY MEANS OF A PUNCH HAVING A SLANTED SURFACE TO THEREBY PRESS SAID END AND SIDE WALLS DOWNWARDLY AGAINST SAID DIE AND IN A DIRECTION AWAY FROM SAID FRONT WALL, AND TO THEREBY CAUSE SAID BACK AND SIDE WALLS OF SAID DRAWN SHELL TO BULGE OUTWARDLY AND CAUSE PART OF SAID WALLS TO BE PRESSED AGAINST SIDE DIE AND TO BE BENT TO FORM THE FLANGES ON THE THREE SIDES OF SAID DRAWN SHELL, AND PERMITTING THE FRONT WALL AND PART OF THE BOTTOM WALL AT THE FRONT END OF SAID DRAWN SHELL TO BULGE A PREDETERMINED AMOUNT UPWARDLY YET LIMITING THE LATERAL BULGING OF THE FROM WALL OF SAID DRAWN SHELL TO THEREBY PREVENT THE FORMATION OF A FLANGE AT THE FRONT OF SAID DRAWN SHELL, AND RELIEVING THE INTERNAL PRESSURE AND REMOVING THE PUNCH TO THEREBY PERMIT THE REMOVAL OF THE FROMED SHELL FROM SAID DIE.

Claim 2

THE METHOD OF MANUFACTURING A STEEL SHELL HAVING AN OPENING WHICH IS DEFINED BY THE EDGE OF ONE SIDE WALL OF THE SHELL AND BY AN INWARDLY BENT FLANGE WHICH IS INTEGRAL WITH THE OTHER THREE SIDE WALLS OF THE SHELL, COMPRISING THE STEPS OF, DRAWING A BLANKET SHAPE TO A FORM HAVING AN OPENING GENERALLY OF EQUAL SIZE TO THE OPENING OF THE SHELL TO BE PRODUCED BY THIS METHOD, AND HAVING A FRONT WALL SUBSTANTIALLY SHORTER THAN THE BACK WALL, SAID FRONT AND BACK WALLS BEING INTEGRAL WITH A BOTTOM WALL AND TWO SIDE WALLS TO DEFINE A DRAWN SHELL HAVING SUBSTANTIALLY GREATER DEPTH AT ITS BACK THAN AT ITS FRONT END, SECURING SAID DRAWN SHELL IN A DIE, APPLYING HYDRAULIC PRESSURE TO THE INSIDE OF SAID DRAWN SHELL, APPLYING EXTERNAL PRESSURE TO THE BOTTOM WALL OF SAID DRAWN SHELL BY MEANS OF A PUNCH HAVING A SLANTED SURFACE TO THEREBY PRESS SAID END AND SIDE WALLS DOWNWARDLY AGAINST SAID DIE AND IN A DIRECTION AWAY FROM SAID FRONT WALL, AND TO THEREBY CAUSE SAID BACK AND SIDE WALLS OF SAID DRAWN SHELL TO BULGE OUTWARDLY AND CAUSE PART OF SAID WALLS TO BE PRESSED AGAINST SIDE DIE AND TO BE BENT TO FORM THE FLANGES ON THE THREE SIDES OF SAID DRAWN SHELL, AND PERMITTING THE FRONT WALL AND PART OF THE BOTTOM WALL AT THE FRONT END OF SAID DRAWN SHELL TO BULGE A PREDETERMINED AMOUNT UPWARDLY YET LIMITING THE LATERAL BULGING OF THE FROM WALL OF SAID DRAWN SHELL TO THEREBY PREVENT THE FORMATION OF A FLANGE AT THE FRONT OF SAID DRAWN SHELL, AND RELIEVING THE INTERNAL PRESSURE AND REMOVING THE PUNCH TO THEREBY PERMIT THE REMOVAL OF THE FROMED SHELL FROM SAID DIE.