Abstract: An anti-collision apparatus comprises an anti-collision cover and a detection portion. The detection portion is provided outside the bottom end of the anti-collision cover along the axial direction of the anti-collision cover, and an axial clearance is provided between the detection portion and the anti-collision cover. The detection portion is configured to collect a trigger signal and output a collision signal according to the trigger signal; the trigger signal comprises a mechanical trigger signal or an electromagnetic trigger signal generated in the case that the axial clearance is reduced to a target value.

Abstract: An anti-collision apparatus comprises an anti-collision cover and a detection portion. The detection portion is provided outside the bottom end of the anti-collision cover along the axial direction of the anti-collision cover, and an axial clearance is provided between the detection portion and the anti-collision cover. The detection portion is configured to collect a trigger signal and output a collision signal according to the trigger signal; the trigger signal comprises a mechanical trigger signal or an electromagnetic trigger signal generated in the case that the axial clearance is reduced to a target value.

Abstract: Provided is a head positioning frame that includes an upright rod, a base ring, and a head nail. The upright rod includes at least two connecting portions, and at least one of the at least two connecting portions is made of an insulating material, such that the upright rod, the base ring, the head nail, and a head to be positioned are incapable of forming an electrical circuit loop.

Abstract: A positioning head frame for gamma knife is provided. The positioning head frame includes a base ring, a plurality of vertical rods circumferentially arranged on the base ring and a plurality of head nails in threaded connection with the plurality of vertical rods. At least one of the base ring and the vertical rod is insulated.