Mulching Mower Deflector Plate Pressure Gradient
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Solution Overview
Problem
Existing mulching mower units accumulate a large volume of grass clippings in the cutting chamber, which aesthetically mar the mown field when the blade stops rotating and the clippings fall to the ground.
Innovation Solution
A mulching mower unit with a deflector plate positioned radially outward of the rotary shaft within the cutting chamber, creating a pressure gradient that directs grass clippings from the rear region to the front region, reducing accumulation and preventing a large volume from falling when the blade stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mulching mower unit uses a cylindrical shroud with a blade rotating inside to achieve good mulching performance, then the grass clippings undergo several cutting operations to produce finer clippings, but a large amount of grass clippings accumulates within the cutting chamber and falls on the ground as a mass when the blade stops rotating
Solution Approach 1:
The cutting chamber is divided into a rear region and a front region by introducing a deflector plate. The deflector plate creates a partition that allows grass clippings to be processed in different zones, with the rear region handling initial accumulation and the front region facilitating discharge to the ground.
Solution Approach 2:
A deflector plate is introduced as an intermediary component between the blade and the ground. This deflector plate redirects grass clippings from the rear region toward the front region and ultimately to the ground, preventing direct accumulation in the cutting chamber while maintaining mulching effectiveness.
2Productivity
If the deflector plate is arranged rearward from the rotary shaft, then the rear region produces greater pressure than the front region, allowing grass clippings to flow from rear to front and fall on the ground, but the structure becomes more complex
Solution Approach 1:
The deflector plate is positioned specifically in the rear region of the cutting chamber, creating a localized pressure differential. This localized arrangement generates higher pressure in the rear region compared to the front region, driving grass clippings to flow from rear to front without requiring complex mechanical discharge systems.
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 deflector plate effectively reduces the amount of grass clippings in the cutting chamber, ensuring a cleaner appearance of the mown field by smoothly distributing pressure and facilitating the flow of clippings to the ground during rotation.
Implementation Method 1
the deflector plate includes a main body having an inner edge facing the rotary shaft and an outer edge spaced apart from the inner edge radially outward of the rotary shaft. The outer edge of the deflector plate is positioned closer to the ground than the inner edge of the deflector plate... the rear region produces a pressure greater than the front region when the blade rotates. Such a difference in pressure allows grass clippings in the rear half of the cutting chamber to flow from the rear region to the front region
Data Source
AI summary
A mulching mower unit includes a mower deck, a rotary shaft, a blade, a shroud, and a deflector plate. The shroud has a circumferential wall including a rotational trajectory of the blade, and extends downward from a bottom surface of the mower deck to an area adjacent to the blade. The deflector plate is provided above the blade and radially outward of the rotary shaft in a running direction in an inner space of the shroud. The deflector plate includes a main body having an inner edge facing the rotary shaft and an outer edge spaced apart from the inner edge radially outward of the rotary shaft. The outer edge is positioned closer to the ground than the inner edge.