LOCKING DEVICE FOR LID FOR UNDERGROUND CONSTRUCTION

Japanese Patent JPH1193193

A

PROBLEM TO BE SOLVED: To reduce the wall thickness of a lid body, prevent the occurrence of shrinkage cavities, and reduce man-hours by allowing an engaging member provided at the lid body corner to swing through the advance and retreat of an operation lever, and engaging it to the support flange by the movement of a bend lever, or releasing its engagement. SOLUTION: The lid body 20 of a manhole M is cast by projectingly setting a table 21 furnished with an axial hole 22 at the surface corner part, and a nut member 31 is inward fitted in the hexagonal large-diameter part 23 of an axial hole 22 lower end to then be fastened by a reversed C-shape support plate 32. On the other hand, an engaging member 35 having a lever piece 38 provided at the root part is installed by rotatably inserting a swing shaft 36 in the support hole of a support plate 32, and permitting an engaging piece at its distal end to be located on the lower side of the support flange 12. By inserting an operation lever 50 in the nut member 31, and putting its distal end surface to be in contact with the lever piece 38 to advance and retreat for allowing the engaging member 35 to swing by the movement of a bend lever, and also an engaging piece 37 to be engaged with the support flange 12, or its engagement to be released. The engaging member 35 swings appropriately irrespective of the wall thickness of the lid body 20, resulting in the decrease of the wall thickness of the lid body 20, the prevention of the occurrence of shrinkage cavities, and the reduction of man-hours.

KOJIMA MASA

JP26927197A

April 06, 1999

September 15, 1997

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ASAHI TEC CORP

E02D29/14; (IPC1-7): E02D29/14

Yuji Nosue

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