| 摘要 |
In a manhole or access cover having at least one recess into which a key or other implement can be inserted to enable the cover to be lifted or levered from its frame, the recess comprises two undercut apertures 16, 17 of different depth with a step 14 between them, and a crossbar 15 extending across the mouth of the recess at a location spaced above the step. The crossbar 15 has a rebate on its underside. The specification illustrates a variety of known lifting tools for which the recess is suitable-namely (a) a rod having opposed rectangular ears for quarter-turn interlock; (b) the hooked bar 24 shown; (c) a pair of inter-pivoted caliper arms; (d) two forms of lifting lever or handle which are clamped to the cover by screw- threaded means; (e) a pick-axe head. <IMAGE> |
