Flail Mower Gear Transmission for Increased Working Width

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Solution Overview

Problem

Belt transmission in flail mowers limits the working width, leads to potential damage and power loss, and requires frequent maintenance, as it exceeds permissible vehicle dimensions and results in slipping and heat generation.

Innovation Solution

Replacing belt transmission with a slim gear transmission using spur gears, incorporating a bevel gearbox, shear clutch, and parallel key for overload protection, and optimizing the gear housing design for minimal width and efficient torque transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If belt transmission is used to transfer torque from the tractor to the rotor, then the machine can operate with simple construction, but the transmission width increases by about 20 cm which exceeds the maximum permissible vehicle width of 306 cm and limits the working width

Engineering Contradiction:
Improvetransmission constructionVSAvoidtransmission width
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent replaces the belt transmission system with a gear transmission system consisting of spur gears and a bevel gearbox. This substitution eliminates the need for wide belt transmission components while achieving the same torque transfer function, reducing the transmission width from approximately 20 cm to a compact gear train configuration that fits within the 306 cm maximum vehicle width regulation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent reconfigures the transmission system by changing the dimensional arrangement from a wide belt-driven layout to a compact gear train with vertical and radial gear arrangements. The bevel gearbox changes the torque angle from perpendicular to parallel to the rotor, allowing the power flow to be redirected through a narrower path that reduces the overall transmission width while maintaining effective torque delivery to the rotor.

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

2Ease of manufacture

If belt transmission is used, then the installation is simpler, but belt slippage does not occur quickly enough under overload conditions which can lead to damage to the tractor or rotor

Engineering Contradiction:
Improvetransmission installationVSAvoidoverload protection
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the friction-based belt transmission with a positive engagement gear transmission system. The spur gears and bevel gearbox provide direct tooth-to-tooth contact that prevents slippage under normal operating conditions and overload situations, ensuring reliable torque transfer and protecting the tractor and rotor from damage while maintaining structural integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent incorporates a shear clutch within the gear transmission system that is pre-configured to fail in a controlled manner under excessive load. This shear clutch acts as a safety mechanism that disengages the power transmission before damage can occur to more critical components, providing beforehand protection against overload conditions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If belt transmission is used, then the initial setup is simpler, but it causes power loss and higher fuel consumption

Engineering Contradiction:
Improvetransmission setupVSAvoidpower loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent replaces the belt transmission system with a gear transmission system consisting of spur gears and a bevel gearbox. This substitution eliminates the friction and slippage losses inherent in belt-driven systems, providing more efficient mechanical power transfer from the tractor PTO shaft to the rotor. The direct gear engagement ensures that torque is transmitted with minimal energy loss, reducing fuel consumption while maintaining the structural simplicity of the overall transmission setup.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution increases the working width, reduces power loss and fuel consumption, enhances durability, and minimizes maintenance needs, while providing double overload protection and compliance with vehicle width regulations.

Implementation Method 1

a gear transmission, which includes at least two, preferably three spur gears (4, 5, 6) in contact with each other and arranged vertically

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

a bevel gearbox mounted on the flail mower housing for transferring the torque from the PTO shaft, when connected, to the second PTO shaft

Methodology Applied
Scientific EffectBevel gear mechanism: Gear

Implementation Method 3

the second PTO shaft is preferably provided with a shear clutch for overload protection

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP4338567A1A flail mower with an increased working width
Publication Date: 2024.03.20 TEHNOS D O O ZALEC
  • EP4338567A1 patent drawingFigure 1
  • EP4338567A1 patent drawingFigure 2
  • EP4338567A1 patent drawingFigure 3

AI summary

The flail mower with the increased working width is characterised by the replacement of the standard belt transmission with a slim gear transmission. The flail mower comprises: - flail mower housing (8), within which the rotor (7) with hammers (7a) is rotatably mounted, - bevel gearbox (1) for changing the torque angle from a torque perpendicular to the rotor (7) to a torque parallel to the rotor (7), - an element (2) for transferring torque with the mentioned gearbox for changing the torque angle to the gear transmission, - the gear transmission housing, mounted on one side of the flail mower housing (8), - gear transmission, which comprises at least two, preferably three spur gears (4, 5, 6), in contact with each other and arranged vertically, wherein the lowermost gear is connected to the rotor (7) with hammers (7a), and - a connecting element (9), which is installed between the gear (6) and the rotor (7) for connecting the two elements.