Patent ID: 8231639

Claim:
A motor-driven tool for applying an implantation force to a helical fastener sized and configured for penetration in tissue comprising: a tool body; a drive motor carried in the tool body; a driven member coupled to the drive motor, carried by the tool body and operable to apply the implantation force during operation of the drive motor; a carrier on the driven member configured to couple the fastener to the driven member to transfer the implantation force from the driven member to the fastener the carrier comprising a distal portion wherein the distal portion remains within the tool body during implantation of the fastener; and a motor control unit carried in the tool body, coupled to the drive motor, and conditioned to operate the drive motor in phases including: an initial phase operating the carrier to transfer the implantation force to the fastener under conditions that result in only partial implantation of the fastener, with a distal portion of the fastener penetrating tissue such that the distal portion is implanted into the tissue, while a proximal portion of the fastener is retained within the tool body and remains coupled to the carrier, a lull phase commencing at the end of the initial phase interrupting operation of the carrier, and a final phase operating the carrier to release the fastener therefrom and implant the fastener in tissue, wherein after automatically entering the lull phase, the motor control unit requires a final phase command to advance from the lull phase to the final phase.