US Patent 7275466 Multiple-bit driver with spring-loaded actuation

The driver has a number of cartridges assembled around a central axis, engaging each other along abutting longitudinal edges. Each cartridge has its own spring-loaded mechanism for extending or retracting a bit through a central axial opening of a collar at the distal end of the tool. The mechanism translates a small movement of an actuation button into rapid and much larger movement of the bit associated with that cartridge, whether that movement is extension or retraction.