Patent ID: 8728129

Claim:
A locking screw assembly comprising: a plate material having a through hole at least partially defined by a semispherical wall; a first washer at least partially defining a first opening and being insertable into the through hole, the first washer including a widthwise dimension substantially greater than a thickness and comprising circumferentially spaced threaded wall segments, each pair of adjacent threaded wall segments being interposed by a circumferential discontinuity; a second washer at least partially defining a second opening and being insertable into the through hole, the second washer includes a widthwise dimension substantially greater than a thickness; a screw insertable into the through hole and including a threaded head that is configured to threadably mate with the threaded wall segments of the first washer, the screw further including a longitudinal threaded shaft extending from the threaded head; and a driver configured to interact each circumferential discontinuity of the first washer to prevent rotation of the first washer while the screw is inserted into the through hole; wherein the first opening and second opening are sized to allow throughput of the longitudinal threaded shaft; and wherein the semispherical wall is sized to retain the first washer and the second washer within the through hole.