Patent ID: 6652367
Filing Date: 2003-11-25
Classification: B24B

Abstract:
A grinding device adapted for grinding a drill bit, the drill bit having a tip portion that is formed with an apex, two cutting edges that define a tip angle therebetween, two diametrically opposed lip portions, and two diametrically opposed flank portions, each of which is formed between a respective one of the cutting edges and a respective one of the lip portions, said grinding device comprising:a horizontal base plate; a rotary grinding wheel disposed rotatably on said base plate and having an annular grinding surface that is rotatable about a horizontal Y-axis; a first grinding seat disposed adjustably on said base plate and formed with a through hole that extends along a horizontal X-axis which is perpendicular to said Y-axis, said first grinding seat being located in front of said grinding wheel and being adjustable on said base plate so as to be adapted to vary the tip angle of the drill bit to be formed; a sleeve disposed rotatably within said through hole in said first grinding seat so as to permit rotation of said sleeve relative to said first grinding seat by a predetermined angle, said sleeve having a front end surface, an engagement portion, and an eccentric hole, which is formed in said front end surface of said sleeve and which extends in a direction that is inclined with respect to said X-axis; an abrasion measuring device for measuring amount of the flank portions of the drill bit to be ground; and a tubular holding unit for holding the drill bit releaseably therein, said holding unit having a rear end surface and two diametrically opposed engagement portions, and being insertable into said eccentric hole in said sleeve so as to engage said engagement portion of said sleeve with a selected one of said engagement portions of said holding unit such that said holding unit can rotate synchronously with said sleeve, and such that an assembly of the drill bit and said holding unit can move within said sleeve in a rearward direction toward said grinding wheel for grinding of the drill bit until said rear end surface of said holding unit abuts against said front end surface of said sleeve; wherein said holding unit is sleeved on the drill bit, and is disposed initially in said abrasion measuring device so as to fix position of the drill bit within said holding unit based on the amount of the flank portions of the drill bit to be ground, and is then transferred and inserted into said eccentric hole in said sleeve such that the drill bit is in an inclined position within said through hole in said first grinding seat, so that the flank portions of the drill bit can be ground on said grinding wheel by engaging said engagement portion of said sleeve with said engagement portions of said holding unit consecutively and by rotating and moving the assembly of the drill bit and said holding unit rearwardly toward said grinding wheel.