Half-Track Units for Articulated Forestry Machines
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Solution Overview
Problem
Articulated forestry machines face challenges in balancing maneuverability and ground stability, particularly on terrain with varying support strength, due to the limitations of traditional bogie systems which increase weight and complexity, and lack of flexibility in ground pressure adaptation.
Innovation Solution
The implementation of half-track units with pivotable arms and hydraulic piston-cylinder devices allows for adjustable ground pressure distribution between the front and rear sections of the machine, enabling adaptation to different terrain conditions without significant weight increase, by varying the angle of tracker wheels relative to the driving wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a bogie system is used to improve ground stability and distribute vertical loads, then the machine's stability is improved, but the machine's weight increases and ground damage increases
Solution Approach 1:
The bogie system is divided into two independent half-bogie units, each supporting one wheel axle. This segmentation allows the stability function to be distributed across separate modules rather than requiring a single heavy integrated bogie, thereby improving ground stability while reducing overall weight compared to traditional bogie designs.
Solution Approach 2:
The half-bogie units are designed to be oscillating rather than fixed, allowing them to dynamically adapt to terrain variations. This dynamic capability enables the system to maintain stability on uneven ground without requiring excessive weight, as the oscillating mechanism automatically adjusts to ground conditions.
2Stability of the object's composition
If a bogie system is used to distribute vertical loads, then the machine's stability is improved, but the device complexity increases
Solution Approach 1:
The complex bogie system is segmented into two simpler half-bogie units that can be independently mounted on framework sections. This segmentation reduces the complexity of each individual unit while maintaining the overall load distribution function, making the system easier to manufacture and maintain.
Solution Approach 2:
The half-bogie units are designed as universal components that can be applied to either the front or rear framework section of the articulated machine. This multi-functionality reduces overall device complexity by using standardized components rather than custom-designed sections for each location.
3Object-affected harmful factors
If water-filled tires are used to reduce ground pressure, then ground damage is reduced, but the machine loses maneuverability and requires significant weight increase
Solution Approach 1:
The oscillating half-bogie mechanism dynamically adjusts the contact characteristics with the ground, providing low ground pressure similar to water-filled tires but without sacrificing maneuverability. The oscillating motion allows the wheels to adapt to terrain variations while maintaining traction and steering capability.
Solution Approach 2:
The invention uses pneumatic tires within the half-bogie system rather than water-filled tires, achieving similar ground pressure reduction benefits while maintaining the maneuverability and operational flexibility required for forestry machinery.
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 enhances maneuverability and stability, reduces ground damage, and allows for efficient operation on diverse terrains without the need for water-filled tires, improving the overall effectiveness and flexibility of forestry machines.
Implementation Method 1
a piston-cylinder device (25) acting between the wheel axle and the pivotable arm, by means of which the pivotable arm, and thus also the tracker wheel, can be moved
Data Source
Figure 1
Figure 2a~4
Figure 5a~5b
AI summary
The invention concerns an arrangement and a terrain-going motor vehicle. At a terrain-going motor vehicle (1 ) that has a chassis with wheel axles (12, 13) and pairs of wheels (12:1, 13:1 ), a half-track unit (15:1, 15:2) with half-track assembly (15) arranged at a wheel axle. For the regulation of the ground pressure, each half-track assembly (15) comprises: a pivotable arm (20) with a tracker wheel (22) that can pivot centrally to a driving wheel (12:1; 13:1 ) in a vertical plane at the chassis through a joint, a continuous track (24) that runs around tracker wheels (22) and driving wheels (12:1; 13:1 ), a hydraulic system including a piston-cylinder device (25) for the setting of the pivotable arm into angular positions (a) including an inactive position, and an operating condition, a positional valve (29), which valve when set to a first operating condition (A) leads hydraulic medium to the piston-cylinder device (25) for the setting of the pivotable arm (20) and the tracker wheel (22) to the operating condition and in interaction with the support, a third operating condition (C) leads hydraulic medium from the piston-cylinder device (25) for the setting of the pivotable arm (20) and thus also the tracker wheel (22) to the inactive position and away from interaction with the ground, whereby the tracker wheel (22) is placed in the first operating condition (A) in contact with the ground at a pre-determined force.