| 摘要 |
The invention relates to a security manhole that is secured to the mouth of an underground pipe ( 4 ) including an edge ( 2 ) and a hinged cover ( 5 ) having rising cylinders ( 6 ), a peripheral sealing gasket ( 30 ) being provided for. The cover ( 5 ) includes an opening provided with a screw fixed lid ( 8 ), one of the screws compresses a first electrical contact ( 9 ) sending a warning signal to a control centre. Underneath the lid is provided a turning part ( 10 ) pulling in an angular fashion a closing handle ( 14 ) provided onto the edge. In the closed position, said handle ( 14 ) is located on top of the plate ( 18 ) integral with said edge ( 5 ), both having an access ramp providing automatic pre-closing. The closing position is provided through a second electrical contact ( 19 ). In the opening position, the closing handle ( 14 ) is retained by retention pawl ( 15 ) hinged to the edge ( 2 ). Release is provided through a screw ( 21 ) fixed to the cover ( 5 ) upon contact with said retention pawl ( 15 ).
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