WIPING BOLT Russian patent published in 2004 - IPC

FIELD: mechanical engineering. SUBSTANCE: bolt has a head, a rod with smooth-faced cylindrical surface, threaded part with smoothing grooves and guiding belt. On threaded part three smoothing grooves are made at an angle of 120 degrees relatively to each other and having flat bases. Said grooves are located on a length of threaded part equal to two pitches of thread. Diameter of inscribed circle formed by flat groove bases is 0.9-1.0 of minimal inner diameter of bolt rod thread. Diameter of guiding belt matches 0.9-0.95 of diameter of said inscribed circle. Bolt has transient portion starting at guiding groove and ending at threaded part, said portion being made at an angle of 20-30 degrees and imitating a draw-off cone of thread-forming tool. Shape of cutting part on exit of smoothing grooves has an angle of 10-25 degrees, which imitates a fore angle of cutting part of thread- forming tool. EFFECT: decreased bolt screwing moment during start of assembling and at later stages, decreased possibility of jamming during bolt screwing, increased assembling quality. 2 cl, 4 dwg