Plate bending machines

Claim 1

AN INITIAL PINCH PLATE BENDING MACHINE OF THE TYPE COMPRISING A ROLL AROUND WHICH A TUBE IS TO BE FORMED BY BENDING AND ROLLING A PLATE, A SECOND ROLL FOR FORMING WITH THE FIRST ROLL A NIP THROUGH WHICH THE PLATE IS TO BE PASSED, MEANS FOR DRIVING THE TWO ROLLS, AND A THIRD ROLL MOVABLE WITH RESPECT TO THE FIRST AND SECOND ROLLS FOR EFFECTING FIRST AN INITIAL BENDING OF ONE EDGE OF THE PLATE FED TO THE NIP FROM THE SIDE TO WHICH THE THIRD ROLL LIES AND THEN, AFTER REMOVAL AND REVERSAL OF THE PLATE AND FEEDING OF THE PLATE TO THE OTHER SIDE OF THE NIP, THE REQUIRED BENDING AND ROLLING OF THE REST OF THE PLATE, THE MACHINE BEING FURTHER PROVIDED WITH A STIFF SHAFT, MEANS FOR SUPPORTING THE STIFF SHAFT PARALLEL TO THE FIRST ROLL AT SUBSTANTIALLY THE OPPOSITE SIDE OF THE FIRST ROLL TO THE SIDE ALONG WHICH THE BENDING STRESSES WILL BE APPLIED THROUGH THE PLATE MATERIAL BY THE SECOND AND THIRD ROLLS, A PAIR OF BRACKETS NON-ROTATABLY MOUNTED ON THE STIFF SHAFT, AND A PAIR OF BACKING ROLLERS CARRIED BY EACH BRACKET TO BEAR ON THE FIRST ROLL JUST BEYOND THE POSITIONS TO BE OCCUPIED BY THE ENDS OF THE TUBE TO BE FORMED, SO AS TO TRANSMIT BENDING STRESSES FROM THE FIRST ROLL THROUGH THE BRACKETS TO THE STIFF SHAFT.