| 摘要 |
A bore undercutting tool which is composed of a barrel and a cutter feed driver which is inserted for longitudinal displacement but also for co-rotation into the barrel and projects from the rearward end thereof. In a slot provided in the forward end portion of the barrel there is fulcrumed a cutter in the form of a two-armed lever which can be rocked by a cutter feed cam provided on the forward end of the cutter feed driver, in proportion to the longitudinal displacement of the latter relative to the barrel, such that a cutting tool disposed on the one lever arm can either be retracted into the slot or rocked out of same. A spring biases the barrel and the cutter feed driver toward a position in which the cutting tool is withdrawn into the slot. |
