Manhole Cover Locking Mechanism Using Spring Element
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Solution Overview
Problem
Existing closure devices for manholes face issues with weight savings, high material and production costs, susceptibility to contamination and faults, and aesthetic concerns, as well as safety and logistical challenges due to the use of rubber blocks and complex multi-part designs.
Innovation Solution
A closure device with a frame and closure element connected via a hinge-like connection, where the pivot axis is attached to the closure element via a spring element, providing a frictional force to secure the closure element in the closed position and allowing for controlled movement to the open position through translational or rotational forces, reducing the number of components and materials used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a movable bolt is used to lock the closure element, then the closure element can be securely locked in the closed position, but the bolt and its bearing become dirty over time making it difficult or impossible to move
Solution Approach 1:
The invention extracts the movable bolt from the system and replaces it with a spring element that remains fixed relative to the closure element. The spring element's end engages with the frame to provide locking, eliminating the bearing that would accumulate dirt and hinder operation.
Solution Approach 2:
Instead of having a movable bolt on the frame that engages with a recess in the closure element, the invention inverts the arrangement by having the spring element fixed on the closure element engage with a corresponding feature on the frame. This inversion prevents the locking mechanism from being exposed to dirt accumulation.
2Weight of moving object
If the closure element is made lighter to reduce material costs, then production costs are reduced, but the closure element may move from closed to open position under test conditions
Solution Approach 1:
The spring element is pre-loaded to exert a force that presses the closure element against the frame before any external forces act on it. This preliminary action creates sufficient frictional force to prevent unintended movement, allowing lighter closure elements to meet safety requirements.
Solution Approach 2:
The invention replaces expensive cast iron closure elements with lighter, potentially cheaper materials. The spring element provides the necessary locking force to compensate for the reduced weight, enabling the use of more economical materials while maintaining safety.
3Force
If a rubber block is used to provide frictional force, then the closure element can be held in closed position, but the rubber block has significantly lower service life than the frame and locking element
Solution Approach 1:
The invention changes the material parameter from rubber to a metal spring element. The spring element provides the necessary frictional force through elastic deformation while having comparable service life to the metal frame and closure element, eliminating the service life disparity.
Solution Approach 2:
The spring element can be made from materials with properties optimized for both providing sufficient frictional force and achieving long service life, potentially using composite or specially treated materials that outperform rubber in durability while maintaining the required mechanical properties.
4Ease of operation
If an open hinge design is used to allow complete removal of the closure element, then the hinge is visible and dirt can enter the gaps
Solution Approach 1:
The invention extracts the traditional hinge mechanism and replaces it with a spring element that provides both the rotational movement capability and the locking function. This eliminates the open hinge gaps that allow dirt entry while maintaining the ability to remove the closure element completely.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the service life of components, reduces production and logistics costs, improves aesthetics, and ensures safety by eliminating relative movement between the spring element and other parts, allowing for weight reduction while maintaining compliance with safety requirements and reducing the risk of injury.
Implementation Method 1
the spring element exerts in the closed position a force between the pivot axis and the closure element, by which the closure element is pressed against the frame
Implementation Method 2
The resultant frictional force between the closure element and the frame fixes the closure element in the closed position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The closure device (1) has a frame (11) and a closure element (13) that is movable from a closing position into an opening position. A retainer (30) is formed at the frame and forms a hinge-type connection (20) with a pivot axle (21) that is arranged at the closure element. The axle is fastened to the closure element over a spring element (22) as a single piece. A recess is formed at the frame for completely accommodating the spring element in the closing condition of the closure element. A locking pin (42) is formed at the closure element.