Manhole Cover Anti-Theft Hook with Pavement Anchoring
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Solution Overview
Problem
Lighter locking devices for manholes, made from spheroidal graphite cast iron, have become vulnerable to theft as they can be easily removed by a single individual without tools, posing a security risk, especially in high-traffic areas.
Innovation Solution
An anti-theft device featuring a locking hook with 'U' shape and anti-removal collars that secures the lid to the ring, anchored to the ground with bituminous filler or cement, and includes vertical locking tabs to prevent rotation and removal, ensuring the lid remains locked and cannot be easily dislodged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If locking devices are made lighter using spheroidal graphite cast iron, then ease of handling is improved, but vulnerability to theft increases
Solution Approach 1:
The locking device is segmented into multiple functional components: the ring structure, the lid with claws, and the hook with locking tabs. This segmentation allows each component to perform its specific function while working together to provide both ease of handling and theft prevention.
Solution Approach 2:
The hook is pre-installed on the ring with locking tabs positioned to engage with the lid claws. This preliminary arrangement ensures that when the lid is placed on the ring, the locking mechanism is automatically activated, providing security without requiring additional actions from the user.
2Ease of operation
If the lid can be easily removed from the ring without tools, then ease of operation is improved, but security against burglary worsens
Solution Approach 1:
The locking mechanism is designed to be dynamic rather than static. The hook can rotate within its cavity, and the locking tabs can engage or disengage from the lid claws. This dynamic design allows legitimate users to easily open the lid by lifting it, while preventing unauthorized removal without tools.
Solution Approach 2:
The locking tabs act as intermediaries between the hook and the lid claws. They transmit the locking force while allowing controlled movement. The tabs enable the lid to pivot open for authorized access but prevent complete removal without tool intervention, thus mediating between ease of operation and security requirements.
3Reliability
If locking tabs are added to prevent rotation and displacement, then security is improved, but device complexity increases
Solution Approach 1:
The locking tabs are merged with the hook structure, forming an integrated component rather than separate parts. The tabs are extensions of the hook arms, eliminating the need for additional fastening elements and reducing overall device complexity while maintaining security functionality.
Solution Approach 2:
The hook structure serves multiple functions: it provides the main locking mechanism, enables rotation for opening/closing operations, and incorporates locking tabs to prevent unauthorized removal. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
Data Source
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AI summary
This invention relates to an anti-theft device and method applied to hinge-based locking systems, in particular, those used in manholes. The device comprises a ring (1); a lid (2) to connect with the ring; a locking hook (3) of the lid (2) pivot that is placed onto cavities (1A and 1B) located in the ring (1); the lid (2) comprising a set of joining means with the ring. The ring (1) of the assembly can be located either secured to the ground with bituminous filler, cement or fixed with further binders and, to prevent the cover theft, the hook (3) external body is entirely covered with the pavement, so that solely with its removal/destruction will it be possible to take the lid out from the ring. The hook (3) may be placed in a stage when the ring (1) is already partially secured to the pavement. This invention is, therefore, chiefly useful to prevent the cover theft, while maintaining, on the other hand, all typical features and functionalities of the assembly.