Title:
MANHOLE COVER SECURITY LOCK WITH CONTROLLED PRESSURE RELEASE
Document Type and Number:
WIPO Patent Application WO2007146256
Kind Code:
B1
Abstract:
A controllably releasable security locking arrangement for a manhole cover allows a manhole cover to be locked into position but allows the manhole cover to rise up in stages upon development of upward forces in an explosion to vent gases developed by the explosion. A lock body mounts a latch slide which has an outer end and which can be extended to prevent removal of the manhole cover. When a shear pin fails the lock body pivots down, to a limited extent, and a secondary shear pin can also be included allowing the cover to be blown completely free upon development of pressures of a great magnitude. A slotted skirt directs venting gas flow so as to retard the inflow of free air and attenuate the explosion.
Inventors:
STADLER DAVID M (US)
Application Number:
PCT/US2007/013731
Publication Date:
November 27, 2008
Filing Date:
June 12, 2007
Export Citation:
Assignee:
STADLER DAVID M (US)
International Classes:
E02D29/14
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