Locking device for manhole covers

The locking device for manhole covers addresses rainwater ingress by using a guide and seal mechanism to enhance airtightness, ensuring secure closure and reducing the burden on sewage treatment plants.

JP7894264B2Active Publication Date: 2026-07-23NIPPON CHUTETSUKAN KK
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
NIPPON CHUTETSUKAN KK
Filing Date
2022-07-27
Publication Date
2026-07-23

AI Technical Summary

Technical Problem

Existing manhole cover locking devices allow rainwater to enter sewer pipelines through gaps between the iron cover and the opening/closing lid for the handhook hole, posing a burden on sewage treatment plants by exceeding their treatment capacity and risking untreated sewage discharge into public water areas.

Method used

A locking device for manhole covers that includes a lock body, a small closing cover, and a hook receiver, with a guide means and seal means to improve airtightness by guiding the small closing cover's movement and using a sealing member to seal the handhook hole, ensuring the lock body engages and disengages with the hook receiver during opening and closing.

Benefits of technology

Enhances the sealing performance between the manhole cover and the small closing lid, preventing rainwater ingress into sewer pipelines, thereby reducing the burden on sewage treatment plants and ensuring secure closure against unauthorized access.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

To provide a locking device for an iron manhole cover that can lock an iron cover and close a hand hook hole at the same time, improve the sealing performance between the iron cover and a small cover for the hand hook hole, and prevent rainwater from entering a pipe.SOLUTION: A locking device for an iron manhole cover consists of a lock body rotatably attached to a lower part of an iron cover fitted into a receiving frame, a hand hook hole formed in the iron cover, a small closing cover rotatably attached to the lock body for closing the hand hook hole, and a hook receiver formed in the receiving frame. When the iron cover is opened, the lock body rotates about a pivot support in a direction in which the hook is removed from the hook receiver as the small closing cover is lowered. The locking device comprises guide means for guiding the upward and downward movement of the small closing cover, and hand hook hole sealing means for sealing the hand hook hole when the hand hook hole is closed.SELECTED DRAWING: Figure 1
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