Patent ID: 8906076

Claim:
A system for lockably engaging bone screws into a fixation plate, comprising: a locking fixation plate including a threaded screw hole defined by an inner surface surrounding the threaded screw hole, the inner surface comprising an upper countersink and a threaded portion, the threaded portion comprising a pair of threads arranged in a double helix configuration, wherein an end of a first thread of the pair of threads, proximate the upper countersink, is approximately 180° from an end of a second thread of the pair of threads; and a screw comprising a generally conical head tapering into a generally cylindrical shaft that ends at a tip and at least two threads arranged in a helix configuration beginning near the tip and extending along the generally cylindrical shaft and onto the generally conical head, a thread height of each thread being generally constant over a majority of the generally cylindrical shaft and tapering as the thread extends onto the head, wherein the portion of the threads disposed on the generally conical head is configured to interfere with the pair of threads disposed on the inner surface of the screw hole once the screw is screwed into the screw hole to lock the screw into the screw hole.