| 摘要 |
A boring tool comprising a tool head provided with a slot extending transverse to the axis of the tool head in which a pair of opposite cutting knives are guided movable in longitudinal direction of the slot. A spacer is guided in the tool head movable between a first and a second position. In the first position the spacer is located between inner ends of the cutting knives which are spring biased to engage the spacer to be movable with the latter in the longitudinal direction of the slot while holding the cutting knives in a cutting position. In the second position the spacer frees the cutting knives to move under the influence of the biasing springs toward each other to an inactive position. |
