FASTENING ELEMENT (VERSIONS) Russian patent published in 2009 - IPC F16B23/00 F16B35/06 

FIELD: machine building.

SUBSTANCE: fastening element contains head and cylindrical body. In head first groove is made in form of continuous slot consisting of two rectilinear lateral sections and middle part which is made symmetrical relative to vertical axis of fastening element, lying on one line with lateral rectilinear sections. Depth of lateral sections of first groove equals one third of head height. According to first version: depth of middle part of first groove constitutes 0.8 Hh, where Hh - height of fastening element head, to first groove, perpendicular on symmetry axis additional groove is made - slot with depth twice as deep as depth of lateral sections of first groove, with length equal to fastening element head. According to second version, middle part of first groove is made symmetrical relative to fastening element vertical axis in form of semicircle with salience downwards, to first groove perpendicular on symmetry axis additional groove is made - slot with depth twice as deep as depth of lateral sections of first groove, with length equal to fastening element head. According to third version: depth of middle part of first groove constitutes 0.8 Hh, to first groove perpendicular on symmetry axis additional groove is made - slot made similar to first one in form and perpendicular to it. According to fourth version: depth of middle part of first groove constitutes 0.8 Hh, to first groove perpendicular on symmetry axis additional groove is made - slot made only in middle part of head perpendicular to first one and representing semicircle with salience downwards.

EFFECT: increasing reliability of instrument fastening in fastening element head.

4 cl, 9 dwg