Mower Unit With Planar Belt Routing for Low-Height Multi-Blade Cutting

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Solution Overview

Problem

Existing mower units with multiple blades and belt power transmission mechanisms are bulky, heavy, and have limited lifting/lowering strokes due to complex belt configurations, leading to reduced grass-cutting width and increased weight, especially when using electric motors.

Innovation Solution

A mower unit with a wind-around power transmission mechanism using a single power transmission band and auxiliary pulleys, arranged on a base plane parallel to the top plate, to transmit power to at least three blades, minimizing height and weight while allowing a large lifting/lowering stroke.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single power transmission belt is wound around components in a complicated manner to rotate three or more blades, then the number of blades can be increased, but the height of the mower unit becomes large

Engineering Contradiction:
Improvenumber of bladesVSAvoidheight of mower unit
Core Design Contradiction:
Quantity of substanceVSLength of stationary object

Solution Approach 1:

The patent transitions from a three-dimensional belt routing configuration to a two-dimensional planar arrangement. The power transmission belt and all pulleys are arranged to operate substantially within a single plane, eliminating the need for the belt to extend vertically and intersect itself in three-dimensional space. This dimensional simplification reduces the mower unit height while maintaining the capability to drive three or more blades.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If a power transmission belt is wound around components in a complicated manner, then multiple blades can be rotated, but the belt power transmission mechanism becomes heavier and bulkier

Engineering Contradiction:
Improvenumber of bladesVSAvoidweight of belt power transmission mechanism
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

By constraining the belt and pulley system to operate within a single plane rather than utilizing three-dimensional space, the patent eliminates the need for complex vertical extensions and intersections. This planar configuration reduces the overall size and weight of the belt power transmission mechanism while maintaining its functionality to power multiple blades.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Quantity of substance

If the mower unit is configured with a large height to accommodate a complex belt system, then multiple blades can be rotated, but the lifting/lowering stroke becomes small

Engineering Contradiction:
Improvenumber of bladesVSAvoidlifting/lowering stroke
Core Design Contradiction:
Quantity of substanceVSLength of moving object

Solution Approach 1:

The patent resolves this contradiction by flattening the belt transmission system into a two-dimensional planar arrangement. This eliminates the vertical space requirements of complex three-dimensional belt routing, thereby reducing the overall height of the mower unit. The reduced height directly enables a larger lifting/lowering stroke while the planar configuration maintains the capability to rotate three or more blades through the belt.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration enables a compact, lightweight mower unit with a large lifting/lowering stroke, facilitating easy operation and efficient grass cutting with reduced space occupation.

Implementation Method 1

a power transmission band wound around the output pulley and the input pulleys

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a power transmission band wound around the output pulley and the input pulleys and configured to run on a base plane parallel to the top plate

Methodology Applied
Scientific EffectTension: Tension

Data Source

PatentEP4066616B1Mower unit
Publication Date: 2025.09.10 KUBOTA CORP
  • EP4066616B1 patent drawingFigure 1
  • EP4066616B1 patent drawingFigure 2
  • EP4066616B1 patent drawingFigure 3

AI summary

A mower unit 3 includes: a mower deck 30 including a top plate 31 and a side wall 32; and a wind-around power transmission mechanism BM. The wind-around power transmission mechanism BM includes: an output pulley 42 provided for the output shaft 41 of an electric motor 4; three input pulleys 23a, 23b, and 23c each provided for a corresponding blade shaft; and a single power transmission band wound around the output pulley 42 and the input pulleys and configured to run on a base plane parallel to the top plate 31.