Multi-lobe torque driving recess and tool in particular for an orthopedic implant screw
AssigneeCross Medical Products, Inc.
InventorsMoti Altarac, Leonard James Schaust
Life of this patent
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Abstract
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.
Claims19
A fastener with a torque driving recess comprising a central recess defining a peripheral surface having from 2 to 6 grooves spaced on it so that the grooves do not intersect each other, but intersect the peripheral surface to form a sharp distinction between the peripheral surface and the respective groove and where the recess has a longitudinal axis along its depth and the recess is substantially constant in cross section along at least a portion of its length.
An orthopedic implant nut or screw having a head with a torque driving recess comprising a central cylindrical recess defining a peripheral surface having from 2 to 6 grooves equally spaced on it wherein the grooves intersect the peripheral surface but not the adjacent groove.
A spinal implant assembly including a fastener with a torque driving recess comprising a central recess defining a peripheral surface having from 4 to 6 hemi-cylindrical grooves equally spaced on it so that the grooves do not intersect each other, but they do intersect the peripheral surface to form an internally projecting land between each groove wherein the land collectively define the peripheral surface.
Dependencies are inferred from the claim text.