摘要 |
A connection bolt (1) for repeated tightening beyond yield point which bolt (1) comprises a head (2) and a shank which shank is provided with a thread, whereby said head (2) of said connection bolt (1) is provided with at least one indication mark (9) at a fixed defined mutual angle position to at least one indication sign (10), which sign (10) is provided on the free shank (5) end relative to the axis (q-q) of the bolt (1) rotation. This system of marking allows to determine the damage of said bolt (1) exactly and to decide about further ability of said bolt (1) to be used next time without any risk of destruction or decrease in quality of a joint.
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