Multi-lobe torque driving recess and tool in particular for an orthopedic implant screw

摘要

The present invention provides a fastener, such as a screw or nut and tool designed in particular for use with an orthopedic implant system wherein the fastener has a multi-lobed torque driving recess. The recess has a central area bounded by equally spaced hemicircular grooves separated by internally projecting land having two sharp edges. The tool has a corresponding male shape, which in conjugation with the recess, is designed to achieve a controlled torque load with a minimized possibility of stripping the recess or of shearing the torque-driving tip from the tool.