| 摘要 |
<p>The insulating caps are moulded from plastic in a string, with rupture points between successive caps in the string. Successive caps are joined by a link (3), which has its thickness diminishing from the centre of the link, producing narrow regions immediately adjacent to each cap. Each link has a convex surface (30) and a flat surface (31). These surfaces are perpendicular to the walls of the cap at the rupture point. The minimum thickness at the rupture point is of the order of one millimetre. The centre of the link is thicker than at the rupture point.</p> |
