GB1178275A - Trepan. - Google Patents

Abstract

1,178,275. Drilling machine details. AUSTENAL EUROPA Inc. ZWEIGNIEDERLASSUNG KIEL. 20 June, 1967, [4 July, 1966] No. 28373/67. Heading B3C. A surgical drill includes a first shaft 2 able to be rotated by a power drive and arranged to apply the drive through clutch means 4, 7 to a second shaft 8 supporting a drill bit 12, there being stop means which engage the cranium upon penetration of the drill-bit and which then disengage the clutch means 4, 7, the stop means comprising an abutment member 26 on an axially movable non-rotatable spindle 18 which carries a second clutch means 19, 21 having first clutch member with a drive connection to the second shaft 8 and a second clutch member threadedly received on the spindle 18, the second clutch member retracting the spindle and its associated abutment member 26 against the action of a spring 17 and allowing penetration of the drill bit into the cranium only as long as both of the clutch means are engaged. As shown, the drill bit 12 extends through an aperture in the abutment member 26 and drive is engaged when the bit is pressed against the cranium so that the shaft 8 slides against the force of a spring 6 to bring clutch members 4, 7 into inter-engagement. The clutch members 19, 21 are held in inter-engagement by the pressure of the abutment member against the cranium. As drilling proceeds, and the bit 12 advances into the cranium, drive from the shaft 8 is applied via gearing 9, 16 and clutch members 19, 21 to cause (since the member 21 is screwthreaded on the spindle 18) the spindle 18 and the abutment plate to retract back from the drill bit. When the drill bit has cut through the hard material of the cranium the spring 6 causes the clutch members 4, 7 to dis-engage the drive to the bit. Centring pins 24 are provided on the abutment member and a knob 23 may be manually rotated to set the abutment member at the end of the drill bit before drilling commences.