| 摘要 |
A boring tool assembly performs both the rough and finish cutting operations upon a metal work piece without power activation or manual adjustments of the tool units between the cutting strokes. The assembly includes a boring bar having a pair of fixed, diametrically opposed rough cut tool units, and a pair of retractable finish tool units diametrically opposed to each other also. The tool units are automatically operative in response to either the rough cut or the finish cut of the boring tool assembly. Spring biased plungers normally pivot the finish cutting units toward their cutting positions. During the initial or rough cutting operation, forces act upon the heel of the finish tools causing retraction from the cutting position. This is possible due to the cutting edge configuration and angle of orientation of the tools, the positioning of the tools on the trailing side of the boring bar centerline, and the direction of advancement of the boring bar. When the rough cut has been completed, the finish tool units are forced to their outer cutting position across the center line of the bar and the reverse feeding of the tool assembly back through the work piece completes the dual cutting operation. The reverse direction of movement of the tool, the positioning of the cutting tip on the leading side of the center line, and the angle of orientation, preferably (10 DEG ) to the axis of the boring bar, combine to effectively lock the finish tool units in position for efficient performance of the finish cut. Both the rough and finish tools are securely held in mounting blocks and adjustment of both is provided.
|
