Variable Speed Lawn Mower Flap Control
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Solution Overview
Problem
The existing rotary lawn mowers have a limited storage ratio for grass clippings due to a constant rotation speed of the cutter blade, leading to inefficient storage in the grass clippings container, which results in reduced storage capacity and increased frequency of container replacement.
Innovation Solution
A lawn mower with a control unit that adjusts the rotation speed of the cutter blade and the flap angle of the cutter blade in response to the weight of the grass clippings container, optimizing the wind flow to uniformly distribute clippings and enhance storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotation speed of the cutter blade is kept constant, then the cutter blade can maintain stable cutting performance, but the storage ratio of the grass clippings container is limited and grass clippings accumulate unevenly
Solution Approach 1:
The patent applies dynamics by making the cutter blade rotation speed variable rather than constant. The control unit adjusts the rotation speed based on the weight of grass clippings in the container, allowing the system to adapt to changing storage conditions. This dynamic adjustment enables optimization of both cutting performance and storage efficiency throughout the mowing operation.
Solution Approach 2:
The patent implements feedback control by using a weight detection unit to continuously monitor the weight of grass clippings in the container. The control unit receives this weight information and adjusts the cutter blade rotation speed accordingly. This closed-loop feedback system ensures that the rotation speed is optimized based on actual storage conditions, preventing both underutilization and overfilling of the container.
2Quantity of substance
If the rotation speed of the cutter blade is increased to transport grass clippings deeper into the container, then the storage capacity is improved, but the cutting performance becomes less stable and energy consumption increases
Solution Approach 1:
The system dynamically adjusts the rotation speed based on the current storage state of the container. When the container is lightly loaded, the rotation speed is reduced to minimize energy consumption. As the container fills up and weight increases, the rotation speed is progressively increased to maintain effective transport. This dynamic strategy optimizes the balance between storage capacity and energy consumption throughout the operation.
Solution Approach 2:
The patent changes the operational parameters (rotation speed) based on the state of the system (container fill level). By monitoring weight and adjusting rotation speed accordingly, the system adapts its behavior to match actual needs. This parameter adjustment prevents unnecessary high-energy operation when the container is full, while ensuring sufficient transport capability when the container has capacity.
3Quantity of substance
If the rotation speed of the cutter blade is continuously adjusted to optimize storage, then the storage ratio is improved, but the device complexity increases due to control units and sensors
Solution Approach 1:
The system performs self-adjustment by automatically monitoring its own state through the weight detection unit and autonomously modifying its operation through the control unit. This self-service capability eliminates the need for external manual control or complex operator intervention. The system manages its own optimization by using simple weight feedback to automatically adjust rotation speed, reducing the burden on the operator while maintaining intelligent control.
Solution Approach 2:
The patent replaces complex mechanical control mechanisms with an electronic control system that uses weight sensing and automated adjustment. Instead of using complex mechanical linkages or manual control mechanisms, the system employs a control unit that processes weight signals and adjusts motor speed accordingly. This substitution simplifies the overall control architecture while enabling precise and adaptive operation.
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 significantly improves the storage ratio of the grass clippings container, allowing for a larger quantity of clippings to be stored efficiently, reducing the frequency of container replacement, and enhancing the overall efficiency of the lawn mowing operation without requiring operator intervention.
Implementation Method 1
the air lifts generate an upward air flow and a swirl air flow. By orienting the lawn grass growing on the lawn ground to stand upright by the upward air flow, it is possible to cut (clip) the lawn grass by the cutter blade efficiently. The lawn grass (grass clippings) cut by the cutter blade is lifted upward, and swirled in the housing by the upward air flow and the swirl air flow generated by the air lifts, and then, transported into a grass clippings container by the transportation.
Data Source
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AI summary
A lawn mower (10) includes a housing (11) having an opened bottom, a drive source (15) for driving the cutter blade (14) in the housing (11), a flap (52) provided for the cutter blade (14) in a manner that the flap has a changeable flap angle (θr), a grass clippings container (22) storing cut lawn grass, a grass clippings container weight detection unit (113) for detecting weight (Wr) of the grass clippings container (22), and a control unit (117). The control unit (117) controls at least one of the rotational speed (Ner) of the drive source (15) and the flap angle (θr) of the flap (52) in correspondence with the weight (Wr) detected by the grass clippings container weight detection unit (113).