Sheet metal die forming apparatus

Claim 1

IN A BENDING PRESS FOR BENDING IN TWO OPERATIONS ALL FOUR EDGES OF A SUBSTANTIALLY RECTANGULAR SHEET METAL WORK PIECE NOTCHED TO THE BEND LINES AT ITS CORNERS TO DEFINE FLANGE PORTIONS BORDERING A CENTRAL BODY PORTION, SAID PRESS COMPRISING TWO PAIRS OF DIE ELEMENTS, MEANS FOR SUCCESSIVELY SPACING SAID DIE ELEMENTS APART TWO DIFFERENT DISTANCES CORRESPONDING TO DIFFERENT DISTANCES BETWEEN PAIRS OF PARALLEL BEND LINES THAT ARE OPPOSITE ONE ANOTHER, ONE DIE ELEMENT OF EACH OF SAID PAIRS OF DIE ELEMENTS HAVING A LENGTH EQUAL TO THE LENGTH OF THE LONGER BEND LINE TO BE MADE ON SAID WORK PIECE, MEANS FOR RECEIVING SAID WORK PIECE IN REGISTERED POSITION BETWEEN SAID DIE PAIRS, SPACED THEIR GREATER DISTANCE TO INITIALLY BEND THE SHORTER EDGES OF SAID WORK PIECE, SAID WORK PIECE BEING RECEIVED IN ENDWISE REGISTRATION OVER THE ENDS OF THE DIES WHEN SPACED THEIR LESSER DISTANCE TO BEND THE LONGER EDGES OF SAID WORK PIECE, ONE DIE OF EACH PAIR COMPRISING A MOVABLE ELEMENT SIMULTANEOUSLY ENGAGING SAID WORK PIECE ALONG SPACED LINES ON OPPOSITE SIDES OF THE BEND LINE OF THE OTHER DIE TO CLAMP THE BODY PORTION OF THE WORK PIECE BETWEEN THE DIES WHILE BENDING THE FLANGE PORTIONS.