| 摘要 |
<p>A hollow bolt (10) contains first and second electrical contact elements (13, 16) which are moved apart when the bolt is subjected to a predetermined tensile load. A carrier (14) for a first of the contact elements contains an inductor (18) connected electrically between the contact elements, the condition of the contact elements is ascertained by inductive coupling of test apparatus with the inductor.</p> |
