Lock nut

A lock nut adapted to engage with a fastening unit provided with a plurality of fastening threads, said lock nut comprising:

• a head with an inner wall;
• an accommodation space enclosed by said inner wall of said head;
• a nut thread unit spirally disposed on said inner wall of said head;
• and
• an opening formed through an end of said inner wall for allowing an insertion of said fastening unit;
• wherein said nut thread unit including a plurality of thread segments, each of said plurality of thread segments including an upper thread flank and a lower thread flank in opposing relationship to said upper thread flank, said upper thread flank and said lower thread flank being respectively connected to said inner wall and extended outwards from said inner wall, an upper flank reference line being defined by the extension of said upper thread flank, a lower flank reference line being defined by the extension of said lower thread flank, each said upper flank reference line and each said lower flank reference line meeting at a reference base, a pitch area being defined between two adjacent reference bases, a thread area being defined between said upper flank reference line and said lower flank reference line and being opposite to said pitch area;
• wherein said upper thread flank of at least one thread segment includes a first upper flank section and a second upper flank section different from said first upper flank section, with said first upper flank section connected to said inner wall and extended along said upper flank reference line, and with said second upper flank section connected to said first upper flank section, said lower thread flank of said at least one thread segment including a first lower flank section and a second lower flank section different from said first lower flank section, with said first lower flank section connected to said inner wall and extended along said lower flank reference line, and with said second lower flank section connected to said first lower flank section, said second upper flank section and said second lower flank section being extended until said second upper flank section and said second lower flank section converge at a thread crest, said thread crest deviating from one of said two adjacent reference bases so that said thread crest is situated in said pitch area, and the deviation of said thread crest causing said at least one thread segment to be provided with a misaligned portion serving to interfere in an engagement with said fastening unit and press said plurality of fastening threads tightly, thereby allowing said plurality of fastening threads to be firmly wedged into said nut thread unit.