Grass Cutter Duct Airflow Management
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Solution Overview
Problem
Conventional grass cutters face inefficiencies in increasing the total amount of carrier air inside the duct, leading to reduced airflow and disturbance of the carrier air flow generated by rotary blades due to the placement and operation of auxiliary fans within the mower deck.
Innovation Solution
The design includes side walls with openings on the right and left sides to direct fan-generated carrier air into the duct, a guide member to efficiently direct airflow, and a bottom plate configuration that aligns with the conveyance direction, ensuring that carrier air from both rotary blades and fans is effectively guided into the duct without disturbing the main airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If auxiliary fans are arranged inside the mower deck to increase carrier air amount, then the total amount of carrier air can be increased, but the flow of carrier air generated by rotary blades is disturbed inside the mower deck
Solution Approach 1:
The invention divides the air generation sources into two separate locations: rotary blades inside the mower deck and auxiliary fans outside the mower deck. This segmentation allows each component to generate carrier air independently without interfering with the other's airflow pattern, resolving the contradiction between increasing total carrier air and maintaining flow stability.
Solution Approach 2:
The duct serves as an intermediary component that receives carrier air from both the rotary blades (through the mower deck) and the auxiliary fans (directly from outside), and combines them in a controlled manner. This intermediary structure enables the integration of multiple air sources while maintaining proper airflow dynamics.
2Quantity of substance
If auxiliary fans are arranged inside the mower deck, then carrier air can be generated, but the fans occupy space and complicate the internal structure of the mower deck
Solution Approach 1:
The auxiliary fans are extracted from the mower deck interior and relocated to the exterior, mounted on the rear surface of the mower deck. This extraction eliminates the space occupation and structural complexity issues while preserving the carrier air generation function. The fans now operate independently outside the mower deck without complicating its internal structure.
3Quantity of substance
If openings are formed on side walls of the duct body to introduce fan-generated air, then larger amount of carrier air can be introduced into the duct, but the duct structure becomes more complex
Solution Approach 1:
The side walls of the duct body are designed to serve multiple functions: they provide structural support for the duct and simultaneously incorporate openings that enable direct introduction of fan-generated carrier air. This multi-functionality increases carrier air introduction efficiency without requiring separate complex air intake structures, thus avoiding additional structural 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
This configuration significantly increases the total amount of carrier air inside the duct, enhancing airflow efficiency and preventing disturbance of the rotary blade-generated airflow, thereby improving grass clipping conveyance and mower deck strength.
Implementation Method 1
a fan (13) which is arranged above the mower deck (11) and generates carrier air
Implementation Method 2
two right and left rotary blades (12) which are housed inside the mower deck (11) to cut lawn grass and generate carrier air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A grass cutter is provided with a mower and a duct (30). The mower includes a rotary blade which cuts grass by being driven to rotate, a mower deck (11) which houses the rotary blade (12), and a fan (13) which is arranged above the mower deck (11) and generates carrier air. The duct (30) includes a duct body (31) which communicates with the mower deck and extends in a conveyance direction of grass clippings cut by the rotary blade (12), and an opening (32) which is configured to allow carrier air generated by the fan (13) to be introduced into the duct body (31).