Double-cutting shears

Claim 1

DOUBLE-CUTTING SHEARS COMPRISING A CENTRAL BLADE HAVING LATERALLY SPACED OPPOSITE SIDES EACH PROVIDED ALONG ITS UPPER MARGIN WITH AN UPWARDLY DIRECTED SHEARING EDGE, A PAIR OF OUTER BLADES DISPOSED ON OPPOSITE SIDES OF THE CENTRAL BLADE, SAID OUTER BLADES HAVING SPACED ADJACENT SIDES PROVIDED ALONG THEIR LOWER MARGINS WITH DOWNWARDLY DIRECTED SHEARING EDGES FOR COACTING WITH THE SHEARING EDGES OF THE CENTRAL BLADE, MEANS PIVOTALLY CONNECTING THE CENTRAL BLADE ABOUT AN AXIS TO THE OUTER BLADES FOR SWINGING MOVEMENT RELATIVE THERETO BETWEEN OPEN AND CLOSED POSITIONS, EACH OF THE SHEARING EDGES OF THE CENTRAL BLADE HAVING A SMOOTHLY CURVED, UPWARDLY CONCAVE FIRST LINE OF PROJECTION ON A PLANE THAT IS NORMAL TO THE AXIS AND INTERMEDIATE THE SHEARING EDGES OF THE CENTRAL BLADE, EACH OF THE SHEARING EDGES OF THE OUTER BLADES HAVING A SMOOTHLY CURVED, UPWARDLY CONCAVE SECOND LINE OF PROJECTION ON SAID PLANE, SAID LINES OF PROJECTION INTERSECTING AT AN ACUTE ANGLE AND AT A POSITION THAT RESPECTIVELY DECREASES AND MOVES FURTHER FROM THE AXIS AS THE BLADES ARE MOVED FROM THE OPEN TOWARDS THE CLOSED POSITION, SAID OPPOSITE SIDES OF THE CENTRAL BLADE BEING DOWNWARDLY CONVERGENT TO EACH OTHER AND SAID PLANE BELOW THE SHEARING EDGES OF THE CENTRAL BLADE, AND SAID ADJACENT SIDES OF THE OUTER BLADES BEING UPWARDLY DIVERGENT FROM EACH OTHER AND SAID PLANE ABOVE THE SHEARING EDGES OF SAID OUTER BLADES, WHEREBY A DOUBLE CUT CAN BE MADE TO SEVER LATERALLY AN ELONGATED STRIP FROM SHEETSTOCK WITH SUCH STRIP BEING CAUSED TO CURL UPWARDLY ABOVE THE CENTRAL BLADE DURING ITS SERVERANCE, AND WHEREBY SUCH STRIP CAN BE SEVERED FROM THE SHEET STOCK ALONG A CURVE WITH THE STRIP SERVERED ALONG A CURVE BEING AFFORDED LATERAL CLEARANCE BETWEEN THE ADJACENT SIDES OF THE OUTER BLADES BY VIRTUE OF THE UPWARD DIVERGENCE OF THE LATTER, AND WITH LATERAL CLEARANCE BEING AFFORDED EDGES OF SHEET STOCK PREVIOUSLY CONTIGUOUS TO THE SEVERED STRIP BY VIRTUE OF THE DOWNWARD CONVERGENCE OF THE OPPOSITE SIDES OF THE CENTRAL CUTTER.