| 摘要 |
PURPOSE: A manhole cover having open-preventive device is provided, by forming keys on both front and rear sides of manhole cover and simultaneously corresponding manhole supporting frame and duly locating, keys prevent manhole cover from opening and a moving-preventive device prevents both cover sides from moving, consequently a manhole cover improved stability and solidity is installed. CONSTITUTION: A manhole cover installed open-preventive device comprises the step of; locating covers (30a)(30b) on a manhole supporting frame (40); occluding keys of a manhole cover (32)(33) and a manhole supporting frame (42)(43), thereby preventing covers (30a)(30b) from opening by external pressure and noise; a fixing spacer (50) to covers (30a)(30b), thereby maintaining the same clearance between covers (30a)(30b) and preventing from moving to the middle and from opening by long-term usage; scattering space between covers (30a)(30b) by an intersected protrusion(34), thereby preventing pedestrians' accident by falling into the clearance.
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