| 摘要 |
A bit holder for a replaceable bit is disclosed. The bit is of the type having a pointed head portion axially extending from a shaft portion. The bit holder has a holder part for receiving the bit and has a base part for securing to a cutter head. The bit holder part is releaseably secured to the base part for easy replacement. The holder part has at least one reaction surface cooperating with one reaction surface on the base part for counteracting forces arising on the bit while cutting. A bolt extending from the holder part or the base part into a cooperating aperture in the other of the holder part of the base part is utilized to releaseably secure the two pieces together with the reaction surfaces therebetween. The bolt is positioned relative to the reaction surfaces and with respect to the bit so that the gripping force of the bolt counteracts the force of the bending moment created between the bit tip and the reaction surfaces during cutting. |
