主权项 |
1. A craniotomy drill, comprising a main machine (7), a retarder of conventional arts and a locking seat (8) which are successively threadedly connected, a drill transmission rod (2-13) connected to the locking seat (8), the main machine (7) comprising a handle (1) at a lower portion thereof and an accommodating part (2) at an upper portion thereof, a stator (9) and a rotor (5) of a direct current (DC) electric motor being provided inside the accommodating part (2) and a wall (4) of the accommodating part (2) enclosing the stator (9) of the DC electric motor,
wherein the locking seat comprises a boss (2-1) with a through hole, a bearing (2-8) is arranged on an inner wall of a small cylinder (2-16) on the boss (2-1), a support member (2-12) supports the bearing (2-8) and a locking sleeve (2-2) fitted on the boss (2-1), the locking sleeve (2-2) includes a first bulge (2-5) arranged on an upper part of an inner wall of the locking sleeve (2-2) and a second bulge (2-3) arranged on a lower part of the inner wall of the locking sleeve (2-2), a spring (9) is provided between the second bulge (2-3) and an upper bottom face (2-10) of the boss (2-1), a press plate (2-6) is threadedly connected to an outer wall (2-7) of a top part of the small cylinder (2-16) on the boss (2-1) and pressing the first bugle (2-5), a stepped hole (2-11), including concentric holes of different diameters, is respectively formed by the inner wall of the small cylinder (2-16) and by the support member (2-12), corresponding in position to the second bulge (2-3); and a steel ball (2-4) is positioned in the stepped hole (2-11). |