| 摘要 |
<p>A point attack bit has an enlarged head, an integral and coaxial shank extending from the base of the head, and a tip extending from the other end of the head and having a generally frustoconical end with an odd number of side faces disposed between the end and the head. The odd number of side faces create an unbalanced loading on the bit when it engages the surface to be mined, excavated or cut and cause the bit to rotate within a mounting block in which the shank is rotatably received to reduce the wear on and more evenly wear the bit. The faces may be generally flat or they may be arcuate providing a generally frustoconical tip. The tip is preferably a carbide insert operably connected to the head of the bit. In one form, the head is frustoconically shaped and has a smooth exterior. In a second form, the head has a construction similar to that of the tip and preferably has the same number of side faces as the tip with each face of the head and tip generally aligned. <IMAGE></p> |
