Portable Chair Seat Folding Mechanism With Low-Fatigue Spring Mounting
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Solution Overview
Problem
Conventional portable chair self-folding mechanisms experience spring fatigue and disengagement due to excessive spring force, leading to noise and vibration when folding, as the tension spring is always in a loaded state and has a shorter length than the assembly space.
Innovation Solution
A tension spring with hook elements oriented differently, allowing engagement with hanging holes on non-parallel planes, and a cushion pad to absorb noise and vibration, ensuring the spring is not excessively stretched and reducing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the tension spring is made shorter than the assembly space, then the spring can be assembled in the available space, but the spring is always in a loaded state causing excessive spring force, fatigue and permanent deformation
Solution Approach 1:
The hook elements are designed with three-dimensional spatial orientation, where the first hook element extends parallel to the spring axis and the second hook element extends perpendicular to the spring axis. This dimensional arrangement allows the hooks to engage with hanging holes on non-parallel planes, optimizing the spring length to match the assembly space without excessive loading.
2Device complexity
If the hook elements are aligned in a straight line, then the spring structure is simple, but the hook elements cannot easily engage with hanging holes on non-parallel planes
Solution Approach 1:
The hook elements are arranged in different spatial orientations rather than being aligned linearly. The first hook element is oriented parallel to the spring axis while the second hook element is oriented perpendicular to the spring axis, enabling engagement with hanging holes on non-parallel planes and simplifying the installation process.
Solution Approach 2:
The two hook elements are designed with asymmetric orientations relative to the spring axis. This asymmetric configuration allows each hook element to engage with hanging holes on different planes, making the spring easier to install and secure in the assembly space.
3Force
If the spring force is increased to ensure engagement, then the spring can securely hold the seat, but excessive spring force causes noise and vibration when the seat frame collides against the rear legs
Solution Approach 1:
The spring force parameter is optimized by matching the spring length to the assembly space distance. This parameter change ensures the spring operates within appropriate force limits, providing secure engagement while preventing excessive force that would cause noise and vibration during seat frame collision.
4Ease of manufacture
If the spring is excessively stretched to engage hook elements with hanging holes, then the spring can be installed, but the excessive tension causes fatigue and permanent deformation of the spring
Solution Approach 1:
The hook elements are oriented in different spatial dimensions, allowing engagement with hanging holes on non-parallel planes without requiring excessive spring stretching. This dimensional arrangement enables installation while preserving spring strength and preventing fatigue.
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 solution prevents spring fatigue and disengagement, reduces noise and vibration by aligning hook elements with hanging holes securely, and extends the spring's service life while providing effective cushioning during folding.
Implementation Method 1
When the seat is unfolded, the tension spring C is stretched to accumulate a spring force. When the seat is released, the spring force makes the seat be folded into a collapsed state.
Implementation Method 2
the cushion pad can absorb vibration and noise that may occur when the seat, driven by the tension spring, is folded to the collapsed state
Data Source
AI summary
A portable chair has a mechanism for self folding up and cushioning a seat. The mechanism includes a tension spring assembled between a seat frame and a rear leg for collapsing the seat, and a cushioning pad affixed on the rear leg. The tension spring has first and second hook elements disposed on different orientations and engaged with holes. The hook elements are easy to install, and reduce the risk of disengagement after assembly. The length of the spring is substantially equal to the length of the space in which it is assembled, so that it is not excessively stretched during assembly, thereby preventing spring fatigue. The cushioning pad is integrally formed and includes retainer and insert portions through which it is affixed with the rear leg, and a cushion portion that can absorb noise and vibration when the seat is collapsed.