Long leg fixing device
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Solution Overview
Problem
Existing foldable table leg mechanisms rely on elastic forces that can be insufficient or excessive, leading to unintended leg folding due to external forces, and may deform the linking crosspiece, necessitating a more stable and reliable locking mechanism.
Innovation Solution
A long leg fixing device that uses a lever and latch mechanism to grip the crossbeam portion, allowing two-step operation for releasing and maintaining the open-leg state without relying on a strong spring, utilizing a lever cam and latch system to secure and release the legs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-based locking mechanism is used to maintain the open-leg state, then the leg can be kept open, but the elastic force may be insufficient to prevent unintended folding under external forces
Solution Approach 1:
The patent introduces a cam mechanism as an intermediary between the leg positioning system and the locking function. The cam surface converts the positional movement of the leg into a mechanical advantage that presses the locking piece against the crossbeam, providing reliable locking without requiring excessive spring force.
Solution Approach 2:
The patent replaces the direct spring-based locking system with a cam-based mechanical system. Instead of relying solely on spring elastic force to maintain the locked state, the cam geometry provides a mechanical advantage that amplifies the locking force, allowing a weaker spring to achieve the same reliable locking effect.
2Reliability
If the elastic force of the spring is increased to prevent unintended folding, then the locking becomes more reliable, but the linking crosspiece may be deformed
Solution Approach 1:
The cam mechanism acts as a force-distributing intermediary. Instead of concentrating high spring force directly on the crosspiece, the cam surface distributes the force over a larger area and longer duration, reducing peak stresses on the crosspiece while maintaining reliable locking.
Solution Approach 2:
The patent changes the mechanical parameters of the locking system by introducing the cam mechanism. This allows the system to achieve the same locking reliability with lower force parameters, thereby preventing crosspiece deformation.
3Device complexity
If a simple spring mechanism is used, then the device complexity is low, but the mechanism cannot reliably maintain the open-leg state under external forces
Solution Approach 1:
The cam mechanism is introduced as a simple intermediary component that significantly enhances the reliability of the locking system. This single added element provides mechanical advantage and force amplification without substantially increasing the overall complexity of the device.
Solution Approach 2:
The cam mechanism introduces dynamic elements to the locking system. The cam surface geometry creates varying normal forces during the leg movement, providing automatic engagement and disengagement capabilities that improve reliability without requiring complex control systems.
4Reliability
If the locking mechanism engages the crosspiece at multiple points, then the stability improves, but the ease of operation decreases
Solution Approach 1:
The locking mechanism is segmented into distinct functional components: the cam for engagement, the locking piece for securing, and the spring for maintaining force. This segmentation allows each component to perform its specific function efficiently, with the cam providing stable multi-point engagement and the spring-provided locking piece enabling easy release through a single operational point.
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
The mechanism maintains the open-leg state securely without needing a strong spring, enabling easy operation to release and close the legs through a two-step process, preventing unintended folding and deformation.
Implementation Method 1
a latch spring arranged in a space surrounded by the latch receiver and the push plate, and which always urges the latch and the latch receiver
Data Source
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AI summary
The objective of the present invention is to provide a long leg fixing device which, while maintaining the conventional effect of suppressing unsteadiness when legs are open by supporting a bottom surface and a side surface of a linking crosspiec e, maintains the open-leg state by means of engagement with a component on the side surface of the linking crosspiece, without relying on the elastic force of a spr ing, and at the same time facilitating an operation to release a closed-leg state, and a long leg fixing device 1 for a table 2 that is erected using four long legs ha ving a structure in which two of the long legs 3 are linked by means of a crossbea m portion 4, and said two long legs 3 are fitted to the table 2 in such a way as to be capable of pivoting by means of a hinge 6, move together to open and close th e legs, comprising: a base 12 fixed to the table 2; a lever 11 that swings around th e arm pin 13 inserted through the base 12 ; and an arm 8 and a latch 9 adapted to be interlocked with the swing of the lever 11; whereby said arm 8 and said latch 9 grip a seat portion 7 mounted on a crossbeam portion 4.