Rubber Torsion Backrest Tilt Mechanism With Easier Force Adjustment
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Solution Overview
Problem
Existing backrest-tilting devices in reclining chairs are complex in structure and difficult to assemble, requiring multiple parts and adjustments that are cumbersome for users, especially when increasing the initial promoting force, which complicates the assembly process and makes it time-consuming.
Innovation Solution
A simplified backrest-tilting device design where the pivot of the backrest support rod serves as the core of the rubber torsion spring, reducing the number of parts and allowing easy assembly, with an adjustable mechanism that enables the initial promoting force to be adjusted by an operating handle at the seat's lower side, maintaining constant turning resistance regardless of the force level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate core with hexagonal hole is used in the rubber torsion spring assembly, then the torsion spring can be properly assembled, but the number of parts increases and assembly becomes more complex and time-consuming
Solution Approach 1:
The invention merges the core and shaft into a single integrated component. The shaft itself is designed with a hexagonal cross-section that directly serves as the core for the rubber torsion spring, eliminating the need for a separate core with hexagonal hole. This integration reduces the number of parts and simplifies the assembly process while maintaining the functional requirements of the torsion spring assembly.
2Ease of manufacture
If the adjusting screw is disposed in the front lower part of the support, then the initial promoting force can be adjusted, but the user must stoop or turn around to handle it, reducing ease of operation
Solution Approach 1:
The invention relocates the adjusting mechanism from the front lower part of the support to the rear side of the support, changing its spatial position to be more accessible. The adjusting screw is now disposed on the rear side of the support, allowing users to adjust the initial promoting force without stooping or turning around, significantly improving ease of operation while maintaining the adjustability function.
3Force
If the initial promoting force is increased, then the backrest can be held at optional angles more effectively, but the turning resistance of the adjusting screw increases making it difficult to handle
Solution Approach 1:
The invention introduces a gear mechanism as an intermediary between the adjusting screw and the outer tube. The adjusting screw drives a gear that in turn rotates the outer tube, providing mechanical advantage. This gear intermediary allows the user to apply smaller force to the adjusting screw while still achieving the necessary rotation of the outer tube to adjust high initial promoting forces, effectively reducing the perceived turning resistance.
4Force
If multiple force-promoting units with separate cores are used, then the backrest can be forced towards upright position effectively, but the structure becomes more complex and assembly time increases
Solution Approach 1:
The invention integrates the core function directly into the shaft of each backrest support rod. Each shaft has a hexagonal cross-section that serves as the core for its corresponding rubber torsion spring. This integration eliminates the need for separate core components in multiple force-promoting units, significantly reducing assembly time and complexity while maintaining the effectiveness of the promoting force mechanism.
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 simplifies the structure and assembly of the backrest-tilting device, allowing for easy adjustment of the backrest's angle and reducing the complexity of assembly, enabling users to adjust the initial promoting force without increasing turning resistance, resulting in a more user-friendly and efficient reclining chair mechanism.
Implementation Method 1
a rubber torsion spring having an elastic material filed between the core and the outer tube, the core turning with the shaft around an axis with respect to the outer tube so that it is elastically deformed to apply return-rotation force to the shaft
Data Source
AI summary
A back rest tilting device in a reclining chair formed of fewer parts. A force promoting unit energizes a back rest in an upright direction. A rotating force promoting unit with rubber torsion springs includes a laterally extending pivot shaft rotated integrally with the back rest and an elastic body filled between an outer tube locked to a support body coaxially with the core and the pivot shaft so that the elastic body is elastically deformed when the pivot shaft is rotated about the center axis of the outer tube to impart a returning rotating force to the pivot shaft.