Patent ID: 6951052

Claim:
A method for insertion of a fastener into a workpiece in which rotational movement of a longitudinally extending screw member is converted into linear movement of a fastener insertion actuator assembly by intermediate rolling transmission elements disposed between a thread of the screw member and a circumferential surface of the actuator featuring a plurality of annular grooves so as to be in rolling contact with both, the screw member being driven in rotation by a drive system, the method comprising the steps of: (a) determining the energy required to insert the fastener into the workpiece; (b) determining the angular velocity of the screw member required to achieve a kinetic energy level of the screw member and drive system that is sufficient to deliver the determined energy to the fastener insertion actuator assembly; (c) positioning a fastener for insertion; (d) controlling the drive system so as to accelerate the screw member up to the determined angular velocity, the actuator assembly simultaneously being moved by the screw member towards the workpiece; (e) thereafter controlling the drive system so as to maintain the angular velocity of the screw member substantially at the determined magnitude at least until commencement of insertion of the fastener; (f) bringing the actuator assembly into contact with the fastener so as to transfer said kinetic energy into work done in inserting the fastener into the workpiece.