Patent ID: 6199956
Filing Date: 2001-03-13
Classification: B28D,E21C

Abstract:
In a round-shank bit for a coal cutting machine or a similar machine, having a bit head and a bit shank, wherein the bit head has a bit tip maintained by a base element in a receptacle of the bit head, wherein starting at the base element the bit tip tapers in a direction toward a free end of the bit tip, wherein the base element forms a maximum diameter of the bit tip, and wherein the bit tip has recesses on an outer contour, the improvement comprising:the base element (16) having the recesses (17) on an outer circumference of the base element forming the maximum diameter; a clamping sleeve (31) surrounding the bit shank (26), the clamping sleeve having tabs (33) stamped out therefrom and bent off in a direction toward the bit shank, the tabs engaging a circumferential groove (27) formed in the bit shank thereby preventing the clamping sleeve from being pulled off the bit shank, the clamping sleeve further having a longitudinal slit (32); a wear-protection disk (30) having a bore therein, the wear-protection disk bore fitting over the clamping sleeve in the area of the tabs so as to maintain the clamping sleeve is in a prestressed state whereby its longitudinal slit is of a first width; and the wear-protection disk being displaceable in a direction toward the bit head to a position having no contact with the clamping sleeve whereby the clamping sleeve longitudinal slit is of a second width wider than said first width; andwherein, extending in the direction toward the base element (16), the bit tip (10) has a free end area of the bit tip (10) with a rounded foremost point (11) joined directly to and transitioning into a truncated conical first area (12) of right circular cone shape, the conical first area joined directly to and transitioning into a cylindrical transition area (13), the cylindrical transition area joined directly to and transitioning into a truncated conical second area (14) of right circular cone shape, the truncated conical second area (14) joined directly to and transitioning into a truncated conical third area (15) having concavely tapered sides rather than being of right circular cone shape, with all the transitionings being flush thereby presenting a smooth-faced outer surface of the bit tip.