Forestry Machine Auxiliary Wheel Arrangement

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Solution Overview

Problem

Forestry machines face challenges in minimizing surface pressure on soft and boggy ground while maintaining adequate load-bearing capacity, with existing solutions relying heavily on swing-bogie axles and pneumatic auxiliary wheels that are inefficient in load-bearing and durable.

Innovation Solution

A forestry machine arrangement featuring a single-axle set of bogie wheels with auxiliary wheels supported by a transverse shaft and support arms, allowing for adjustable load distribution and reduced surface pressure, with a crawler track connecting the bogie wheels and auxiliary wheels to enhance load-bearing capacity and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If pneumatic auxiliary wheels are used to regulate crawler track tension, then track tension adjustment is achieved, but auxiliary wheel durability decreases due to low air pressure requirements

Engineering Contradiction:
Improvecrawler track tension adjustmentVSAvoidauxiliary wheel durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses pneumatic auxiliary wheels filled with air at controlled pressure to regulate crawler track tension. The air pressure in the auxiliary wheels creates the necessary force to adjust and maintain track tension, replacing mechanical adjustment mechanisms while improving durability through proper pressure management.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Strength

If auxiliary wheels are positioned far from the chassis to increase load-bearing capacity, then load distribution improves, but the support arm structure becomes wide and complex

Engineering Contradiction:
Improveload-bearing capacityVSAvoidsupport arm structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent positions auxiliary wheels at the rear end of the chassis outside the wheel set, utilizing the longitudinal dimension rather than lateral extension. This arrangement increases load-bearing capacity by distributing weight to the rear axle while maintaining a compact transverse profile and simplifying the support structure.

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

3Stress or pressure

If swing-bogie axles are replaced with multiple axles to reduce surface pressure, then load distribution on soft ground improves, but machine complexity and weight increase

Engineering Contradiction:
Improvesurface pressureVSAvoidchassis structure
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The patent segments the chassis into front and rear parts with independent axle arrangements. The rear chassis is equipped with auxiliary wheels on a rear axle that can be independently positioned and loaded, allowing the machine to distribute weight effectively on soft ground while maintaining structural simplicity through modular segmentation.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the auxiliary wheel diameter is made smaller than bogie wheels, then track tension regulation is achieved, but load-bearing contribution from auxiliary wheels decreases

Engineering Contradiction:
Improvetrack tension regulationVSAvoidauxiliary wheel load-bearing capacity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies different wheel diameters to different functions: smaller auxiliary wheels at the rear for track tension regulation and larger bogie wheels for primary load-bearing. This local differentiation of wheel sizes optimizes both track tension control capability and overall load-bearing performance of the machine.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2854510B1Arrangement in a forestry machine and a forestry machine equipped with a corresponding arrangement
Publication Date: 2019.05.08 PONSSE OY
  • EP2854510B1 patent drawingFigure 1
  • EP2854510B1 patent drawingFigure 2a
  • EP2854510B1 patent drawingFigure 2b

AI summary

The invention relates to an arrangement in a forestry machine (100), in which arrangement there is - a chassis (12 ), - a single-axle set of wheels (13) pivoted to the chassis (12), and - at least one auxiliary wheel (18) fitted the outside the set of wheels (13), in order to increase the load-bearing capacity of the rear part (19) of the chassis ( 12 ). - The arrangement further includes - at least one support arm (20) arranged to carry the said auxiliary wheel (18) at its first end (22) and pivoted at its second end (24) to the said chassis (12) with the aid of a transverse shaft (23), - a support surface (36) attached to the chassis (12) and a counter surface (38) attached to the said support arm (20), for limiting the transverse movement of the support arm (20 ). - The invention also relates to a corresponding forestry machine.