Asymmetric Switch Knob Surface for Fatigue-Free Lever Operation
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Solution Overview
Problem
Existing operation levers for work vehicles require significant thumb bending and can cause discomfort and fatigue, especially when operators with varying thumb sizes or alternating operators use them.
Innovation Solution
The operation lever features a switch knob with an oblique operation surface design, where the front operation surface is longer and higher than the rear, allowing easy switching between forward and backward movements without substantial thumb posture changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional switch knob with a recessed operation surface is used, then the switch knob can be operated with the thumb pulp, but operators with varying thumb sizes must greatly bend their thumbs causing discomfort and fatigue
Solution Approach 1:
The operation surface is designed with asymmetric dimensions where the front operation surface extends longer in the front-rear direction and has a higher front-side top portion compared to the rear operation surface. This asymmetric design allows operators with different thumb sizes to comfortably reach and press the appropriate pressing portions without excessive thumb bending, thereby reducing discomfort and fatigue while maintaining ease of operation.
2Adaptability or versatility
If the operation surface is made symmetric, then the design is simpler, but it cannot accommodate operators with different thumb sizes without causing discomfort
Solution Approach 1:
Different regions of the operation surface are given different dimensions and heights to suit different thumb sizes. The front operation surface has a longer extension and higher top portion compared to the rear operation surface, creating localized variations that accommodate diverse operator anatomy. This local quality differentiation enhances adaptability to different thumb sizes while keeping the overall design relatively simple.
Data Source
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AI summary
An operation lever of a work vehicle has the operation surface including: a connection portion extending in the width direction; a front operation surface extending obliquely so that a height from a reference plane increases from the connection portion toward the forward side of the connection portion in a cross-sectional view including a front-rear directions and a front-side edge of the operation surface being defined as a front-side top portion; and a rear operation surface connected to the front operation surface via the connection portion, extending obliquely so that a height from the reference plane increases from the connection portion toward the backward side of the connection portion and a rear-side edge of the operation surface being defined as a rear-side top portion. A length in front-rear directions along the reference plane in the front operation surface is larger than a length in the front-rear directions along the reference plane in the rear operation surface. A height of the front-side top portion from the reference plane is higher than a height of the rear-side top portion from the reference plane.