Patent ID: 7682120

Claim:
A positive locking machine screw mechanism comprising: a screw having a head and a body including male threads formed thereon, said threaded body having at least one longitudinal segment devoid of threads and wherein said male threads generally cover one-half of a total surface of said body; a work piece defining a hole having female threads formed on a surface defined therein for receiving said screw, said threaded hole further defining at least one longitudinally extending segment devoid of said female threads and wherein said female threads generally cover one-half of a total of said surface; wherein: said longitudinal screw segment devoid of male threads and said longitudinal hole segment devoid of female threads are arranged such that said screw body is longitudinally received in said hole without engagement of said male screw threads with said work piece female threads; multiple ones of said male screw threads and multiple ones of said work piece female threads engage one with the other substantially simultaneously upon rotation of said screw with respect to said work piece; the screw resulting in maximum engagement of said male screw threads in said work piece female threads via a maximum of one-half of a rotation, and a locking feature, wherein said locking feature provides a frictional fit between said male screw threads and female screw threads which securely limits a securing rotation to a maximum of one-half of a rotation and retains said screw in said work piece for both insertion and removal, wherein the locking feature is selected from a group consisting of: a. a major diameter of said male screw threads being marginally greater than a major diameter of said work piece female threads thereby causing a frictional interference between said male and female threads for securely retaining said screw in said work piece, b. a major diameter of male threads as defined by thread tops is marginally greater than the major diameter of female threads as defined by thread bottoms, c. a width of individual male threads are marginally wider than the female width of female threads thereby causing a frictional interference fit of male threads within female threads, and d. a minor diameter of male threads as defined by thread bottoms can be marginally smaller than the minor diameter of female threads as defined by thread tops.