| 摘要 |
<p>A closure for sealing a circular opening in a pipe or vessel (2) is provided comprising a closure body (1), a plurality of arcuate locking members (5) mounted on the closure body and movable between released and engaged position. An operating member (6) which may be moved angularly about an axis offset from the centre of the closure body (1) by manipulation by an operator is connected to a drive pinion (7) angularly movable so as to be therewith. The drive pinion (7) includes an eccentric drive pin (8) journaled at one end of one locking member (5). A toothed wheel (10) is angularly movable about the central axis of the closure and meshes with the drive pinion (7) and with a plurality of slave pinions (14). The slave pinions (14) are mounted one at the other end of said one locking member (5) and one at each of the ends of the other locking members (5). Each slave pinion (14) also includes an eccentric drive pin (13) journaled on the respective locking member (5). In operation movement of the operating member (6) causes movement of the drive and slave pinions (7,14) such that the drive pins (8,13) move the locking members (5) to either their released or engaged position. Suitably the closure further includes a safety pressure release means (16) which interlocks with the operating member (6) and has to be released before the operating member can be manipulated to open the closure. A further safety feature against residual pressure consists of a safety latch (18) which limits the opening movement of the closure.</p> |
