| 摘要 |
1. The device for making radial crack-generating slits is equipped with a housing located in the head with the conical centring tip and a slit that functions as the slideway for thrusting cutters. The other ends of the cutters are connected to the housing with a bolt, located in another longitudinal slit in the head, to connect it to the housing, while allowing it to slide along the device axis. It also contains the retracting spring located between the housing and the head, which is to maintain the extreme extended position, according to patent No. 171 508. Unique characteristics: It has a double-cone tip (12) with the known centring cone (13), located outside the head (2), and the extending cone (14) located inside the head (2), between the thrusting cutters (4). The extending cone points in the opposite direction to the centring cone. |
