Armrest Frame Reinforcement for Weight Reduction and Rigidity
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Solution Overview
Problem
Conventional armrest designs face challenges in reducing weight while maintaining rigidity and ease of assembly, with a complex mechanical unit that increases the number of parts and weight, and issues with contact noise and size reduction.
Innovation Solution
The armrest design incorporates a reinforcement frame with a thicker thickness than the main frame, fixed to a shaft with a one-way clutch on the seat frame, allowing for reduced weight and size, improved assembly, and reduced contact noise by integrating the retaining portion on the stationary frame, and using a tubular shaft with a nut inside for compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical unit (lock drum, base plate, cover plate) is provided on the armrest to restrict rotation, then rotation control function is achieved, but the number of parts increases and weight reduction becomes difficult
Solution Approach 1:
The patent merges the lock drum, base plate, and cover plate into a single integrated mechanical unit that is fixed to the seat frame. This consolidation maintains the rotation control function while reducing the number of separate parts and simplifying the overall structure.
Solution Approach 2:
The integrated mechanical unit serves multiple functions: it acts as the lock drum for rotation restriction, provides the base plate for mounting, and includes the cover plate for protection and structural support. This multi-functionality eliminates the need for separate components.
2Weight of moving object
If the main frame is made thinner to reduce weight, then weight reduction is achieved, but the rigidity of the armrest near the shaft deteriorates
Solution Approach 1:
The patent applies different thickness qualities to different parts of the frame structure. The main frame is made thinner for weight reduction, while the reinforcement frame is made thicker specifically at the portion near the shaft to maintain local rigidity where it is most needed.
Solution Approach 2:
The patent uses a composite frame structure consisting of two different frames (main frame and reinforcement frame) with different thicknesses. This composite approach allows optimization of weight and strength by combining components with different properties.
3Device complexity
If the lock spring is allowed to contact the shaft directly, then the structure is simplified, but contact noise increases
Solution Approach 1:
The patent introduces a buffer member as an intermediary component between the lock spring and the shaft. This buffer member prevents direct contact between the lock spring and shaft, thereby reducing contact noise while maintaining the simplicity of the overall structure.
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 configuration results in a lighter, more rigid, and easier-to-assemble armrest with reduced noise and size, providing a robust and stable feel while minimizing the number of parts and allowing for efficient rotation control.
Implementation Method 1
a lock spring including a coil portion fitted onto an outer peripheral surface of the shaft... the lock spring being configured to restrict the rotation of the rotatable frame in one direction with the coil portion tightening the shaft
Data Source
AI summary
An armrest is fixed to a shaft (20) of a one-way clutch (1) that is provided on a seat frame, and is rotatable together with the shaft (20) relative to the seat frame. The armrest is configured to be switchable by the one-way clutch (1) between a locked state in which rotation of the armrest in a downward direction is restricted and an unlocked state in which rotation of the armrest in upward and downward directions is allowed. The armrest includes a main frame (100) constituting a framework of the armrest, and a reinforcement frame (200) having a thickness larger than that of the main frame (100), the reinforcement frame (200) and the main frame (100) lying one over another. The reinforcement frame (200) is fixed to the shaft (20).