Skull tong

Claim 1

A skull tong for rigid engagement with a skull, comprising: a rigid frame comprising a first and a second arm member, and a transverse member joining the arms together, the members lying in substantially the same plane, and the arm members extending in the same general direction away from the transverse member and being spaced apart from one another so as to form a region between the members which is open at one end to receive a skull; a first and a second passage in the respective first and second arm members, and a third passage in one of said members, which third passage is spaced from the other passages, all of said passages opening into said region and each having a respective central axis; a thread in each of said passages; a first, second and third engagement rod, each rod having a respective central axis of rotation coaxial with the central axis of the respective passage; a thread on each of said engagement rods coaxial with the central axis of the rod, said engagement rods being threadedly engaged to the thread in the respective first, second and third passages, whereby rotating said rods moves the rods along their respective central axes into and out of said region, the threads of the respective passages and of the engagement rods which are threadedly engaged thereto having a dimension of pitch; a first, second and third lock means carried by the first and second arm members and by the transverse member, respectively, for engaging the respective engagement rods to hold them in a respective selected angular position; a drill on the end of each engagement rod concentrically with the respective central axis said drill comprising cutter means and a non-cutting portion which is axially aligned with the cutter means, said non-cutting portion providing a surface for engagement with the wall of a hole in the skull which is cut by the respective cutter means, the cutter means comprising an intersection with the said portion, and said portion comprising a fragment of a surface of revolution, whereby the frame may be placed over a skull with the engagement rods retracted sufficiently to clear the skull, and then the engagement rods may be rotated so as To advance them into the region and against the skull, further turning of the engagement rods causing the cutter means to drill respective holes in the skull to receive them, the pitch of the threads and the cutting capacity of the cutter means being so inter-related that the cutter means will cut a hole in the skull at a rate sufficient to enable the drill to enter the skull without substantial compression of the skull adjacent thereto, and engagement of the engagement rods by the respective lock means holding them in a selected position in the respective hole, thereby to keep the skull tong engaged to the skull.