Patent ID: 6370931
Filing Date: 2002-04-16
Classification: B21D,Y10T

Abstract:
A punch and die combination for producing a gear wheel having a perimeter profile defining gear teeth including a tip diameter, from a blank of the same diameter as the tip diameter, the combination comprising:a trim punch (5) having a perimeter profile the same as the perimeter profile of the gear wheel; a cooperating trim die (1) defining a bore (10) having a perimeter profile complimentary to the perimeter profile of the punch (5), being dimensioned to closely mate with the bore (10) and having a radiused edge (8) to facilitate metal flow, wherein a clearance between the trim punch and the trim die bore does not exceed one percent of a thickness of the blank; a blank engaging shedder (2) displacable within the bore (10) for engaging the blank; a stripper (4) encircling the trim punch (5) and displaceable therealong for removing surplus stock after trim operation; and a nest plate (3), in use, clamped between the trim die (1) and the stripper (4), defines an aperture and a tapered lead (14) to the aperture for positioning the blank and for preventing material being trimmed from the blank from moving laterally beyond the aperture and the tapered lead (14); wherein the trim die (1) and trim punch (5) cooperate to trim waste material from between the gear teeth by trimming only sides and roots of the gear teeth without the blank and for preventing material being trimmed from the blank from moving laterally beyond the aperture and the tapered lead (14); wherein the trim die (1) and trim punch (5) cooperate to trim waste material from between the gear teeth by trimming only sides and roots of the gear teeth without changing the tips diameter to produce scrap slugs connected by material extruded laterally by the trimming operation into the tapered lead (14) as a scrap ring removable in one piece by the stripper (4) while leaving the tips of the gear teeth at the tip diameter, the nest plate (3) being affixed to one of the stripper (4) and the trim die (1).