Patent ID: 7789730
Filing Date: 2010-09-07
Classification: A61C,B24B

Abstract:
1. In a method of manufacturing a treatment device using a press block and grindstone to form at one time a cutting edge portion and raised portion from a thin rod or bar-shaped workpiece to form at a leading edge a working portion having extremely thin angular cutting edges and at an opposite end portion a raised portion having a larger diameter than the working portion, the raised portion being formed so that the diameter increases gradually from the working portion, said method involving inserting an end portion of the rod or bar-shaped workpiece into a chuck and an opposite leading end portion of the workpiece between a pressing surface of a press block having an inclination angle of its pressing surface preset with respect to a grinding surface of a disc-shaped grindstone to produce a taper in the working portion of the workpiece, said workpiece being inserted between the press block and grindstone when the grindstone is at rest, and then grinding opposite surfaces of the workpiece to form first and second finishing surfaces in the working portion, while at the same time grinding the raised portions, the improvement comprising the following steps: (a) calculating the depth of initial pre-grinding of the workpiece on one side thereof at the leading end portion based on set dimensions, taper, grinding length, reference position for the grinding, length of the working portion; (b) initiating a pre-grinding beginning at the leading end portion and progressing along the working portion and then the raised portion at the same time, whereby to form a first finishing margin along the working portion; (c) rotating the workpiece 180°, and then grinding an opposite surface to form a second finishing surface and raised portion at the same time; and (d) rotating the workpiece 180°, and then grinding to remove at least a portion of the first finishing margin along the working portion, whereby to produce a first finishing surface and a ground workpiece substantially free of eccentricity.