Grass Mower Blade Offset Aligns Rotation Locus with Wheel Tracks
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Solution Overview
Problem
Conventional grass mowers are inefficient in cutting grass that assumes a forwardly leaning posture, as the cutting action from the blades does not effectively engage with the grass, leading to incomplete cutting and reduced performance.
Innovation Solution
A grass mower design with a mower unit positioned between the front and rear wheels, featuring a rotary blade unit with blades offset to align with the tread-on tracks of the front wheels, ensuring that the rotation locus of the blades overlaps with the path of the front wheels, allowing for efficient cutting of forwardly leaning grass while maintaining a compact design and facilitating maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blade is rotated from the left side to the right side (clockwise), then the blade can cut grass pushed down by the front wheel, but the cutting performance is insufficient as the blade presses down the grass instead of cutting it efficiently
Solution Approach 1:
The patent inverts the conventional blade rotation direction from clockwise (left to right) to counter-clockwise (right to left). This inversion allows the blade to engage with the forwardly leaning grass from the opposite direction, enabling effective cutting action instead of pressing down the grass, thus resolving the contradiction between cutting efficiency and cutting performance
Solution Approach 2:
The patent introduces asymmetric positioning where the blade rotational shaft is offset from the vehicle centerline. The right blade rotational shaft is positioned at a greater distance from the centerline than the left blade rotational shaft, creating asymmetric cutting paths that optimize blade engagement with grass pushed down by the front wheels, thereby improving cutting performance while maintaining productivity
2Device complexity
If the right blade rotational shaft is disposed on the front/rear direction line through the right front wheel center and the left blade rotational shaft is disposed with slight outward offset, then the blade configuration matches the wheel positions, but the blade cannot effectively cut forwardly leaning grass
Solution Approach 1:
The patent implements asymmetric blade shaft positioning relative to the vehicle centerline, with the right blade shaft offset more significantly than the left. This asymmetric configuration optimizes the blade cutting paths to effectively engage with forwardly leaning grass while maintaining a relatively simple overall device structure, resolving the contradiction between device complexity and cutting efficiency
Solution Approach 2:
The patent applies different offset distances for left and right blade rotational shafts, creating localized quality differences in the blade configuration. This allows each blade to be optimally positioned for its specific cutting zone, improving overall cutting efficiency without requiring complete redesign of the entire blade assembly
Data Source
AI summary
The grass mower includes a front wheel unit having a left front wheel and a right front wheel which are mounted to a vehicle body frame, a rear wheel unit having a left rear wheel and a right rear wheel which are mounted to the vehicle body frame and a mower unit disposed between the front wheel unit and the rear wheel unit downwardly of the vehicle body frame, the mower unit including a rotary blade unit that has at least a left blade and a right blade which are disposed side by side in a vehicle body left/right direction. The rotary blade unit is configured such that a tread-on track of the left front wheel is overlapped with a rotation locus portion of the left blade from the front side to the rear side thereof and a tread-on track of the right front wheel is overlapped with a rotation locus portion of the right blade from the front side to the rear side thereof.