| 摘要 |
A releasable barrier (10) is arranged to swing about an upright pivot (11) and engages a pressure/time-sensitive release mechanism operative to release the barrier (10) automatically when a predetermined pressure or force on the barrier has persisted for a predetermined time. The mentioned parameters are adjustable. The release mechanism incorporates pneumatic force sensors (21, 26) and a pneumatic keep (22), the latter being provided with higher pressure and/or larger piston area to prevent opening of the barrier (10) so long as the force sensors (21, 26) are depressed transiently within a predetermined time limit. |
