Chair back elevation adjustment structure
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Solution Overview
Problem
Office chairs with adjustable back height often face challenges in achieving simplicity, cost-effectiveness, and reliability, as existing solutions are either too complex or excessively costly.
Innovation Solution
A chair back elevation adjustment structure comprising a frame, back board, and adjustment set with a sliding seat, limiting body, torsion spring, and sliders, which allows for adjustable height through a sawtooth-shaped limiting channel and C-shaped trench mechanism, ensuring durability and accurate positioning at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an adjustable back height mechanism is added to the chair, then the adaptability for different users is improved, but the device complexity increases
Solution Approach 1:
The adjustment mechanism is divided into discrete height positions marked by limiting slots in the adjustment board. The limiting body segments the continuous movement into discrete steps, allowing simple position selection without complex control systems.
Solution Approach 2:
The limiting body acts as an intermediary between the user's manual input and the back board position. By rotating the limiting body along the limiting channel, it mediates the height adjustment through a simple rotational motion that translates to vertical positioning.
2Adaptability or versatility
If a complex adjustable back mechanism is implemented, then the height adjustability is improved, but the manufacturing cost increases
Solution Approach 1:
The torsion spring provides automatic rebound function, allowing the mechanism to self-reset when the limiting body is rotated back. This eliminates the need for manual resetting or additional motorized components, reducing manufacturing cost while maintaining adjustability.
Solution Approach 2:
The mechanism uses simple, inexpensive components such as a plastic limiting body, metal torsion spring, and molded adjustment board with limiting slots. These components are designed to be cost-effective and replaceable if needed.
3Ease of manufacture
If the adjustment mechanism is simplified to reduce cost, then the manufacturing cost is reduced, but the reliability may deteriorate
Solution Approach 1:
The torsion spring is pre-loaded to provide cushioning force that absorbs shocks and prevents sudden drops. This beforehand cushioning ensures reliable operation by compensating for potential failures or unexpected forces during adjustment.
Solution Approach 2:
The limiting channel is designed with a sawtooth-shaped curved profile that guides the limiting body along a precise path. This curved geometry ensures reliable positioning at each height level while maintaining a simple overall structure.
4Manufacturing precision
If the limiting channel is made sawtooth-shaped for precise positioning, then the positioning precision is improved, but the manufacturing complexity increases
Solution Approach 1:
The limiting channel is integrated directly into the adjustment board as a molded feature rather than a separate component. This merging of functions allows the sawtooth shaping to be created in a single molding process, achieving precise positioning without increasing assembly complexity.
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 provides a durable, cost-effective, and easily adjustable chair back height mechanism that balances complexity and reliability, allowing users to customize the height to suit different body lengths effectively.
Implementation Method 1
a torsion spring received in the C-shaped trench, two ends protruding from the C-shaped trench and stopped by the recess
Data Source
AI summary
The invention includes a frame, a back board and an adjustment set. The frame has a central trench and an adjustment board with limiting slots and two sliding slots. The back board is connected to the frame and has an opening. The adjustment set is connected between the frame and the back board and includes: a sliding seat having an engagement block received in the opening, and the engagement block having a recess with a through hole; a limiting body received in the recess, having a central bar in the through hole and an extending portion with a limiting bar in the limiting slots, and a C-shaped trench around the central bar; a torsion spring received in the C-shaped trench, two ends thereof protruding from the C-shaped trench and stopped by the recess; and two sliders received in the sliding slots. The sliders and the sliding seat are fixed to the back board.