Payload Weighing via Bogie Arm Deflection in Forest Machines
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Solution Overview
Problem
Existing payload weighing systems for forest machines face challenges such as dynamic forces, increased weight, reduced payload capacity, and limited accuracy when handling various types of payloads, particularly due to the exposure of deflection sensors and complex mounting requirements.
Innovation Solution
A payload weighing device for forest machines utilizing deflection gauges attached to bogie arms at an angle of 20-70°, preferably 30-60°, relative to the longitudinal axis, which measures deflection caused by bending and twisting moments, providing high accuracy without significantly increasing the machine's weight and allowing flexibility with different payload holding devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load cells with strong steel beams are mounted on load crossbeams to measure payload weight, then measurement precision is improved, but the device complexity and weight increase significantly
Solution Approach 1:
The invention extracts the weighing function from the load crossbeams and integrates it directly into the bogie arms. By attaching deflection gauges to the bogie arms, the measurement function is separated from the complex load cell structure, simplifying the overall system while maintaining measurement capability.
Solution Approach 2:
The bogie arms serve dual functions: supporting the wheels and enabling weight measurement through integrated deflection gauges. This multi-functional design eliminates the need for separate load cells and steel beams, reducing device complexity while maintaining measurement precision.
2Measurement precision
If load cells with strong steel beams are used for weighing, then measurement precision is improved, but the weight of the forest machine increases, reducing payload capacity
Solution Approach 1:
The weighing function is extracted from the heavy load cell structure and relocated to the bogie arms. This eliminates the need for additional strong steel beams and load cells, significantly reducing the weight of the weighing system while preserving measurement accuracy through the deflection gauges.
3Ease of operation
If deflection sensors are positioned on vertical side surfaces of bogie arms for easy access, then ease of operation is improved, but the sensors become exposed to damage from thrown objects
Solution Approach 1:
The invention changes the mounting dimension of the deflection gauges from the exposed vertical side surfaces to the protected upper surfaces of the bogie arms. This dimensional change maintains accessibility for installation and measurement while providing natural protection from objects thrown by the wheels.
4Measurement precision
If multiple deflection sensors are arranged on each bogie arm to improve measurement accuracy, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention applies local quality by positioning a single deflection gauge at the specific location on the bogie arm where deflection is most representative of the total load. This targeted placement optimizes measurement accuracy with minimal sensor quantity, avoiding the complexity of multiple sensors.
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 solution achieves accurate payload measurement with reduced complexity and cost, maintaining a high payload capacity and flexibility to handle various payloads, including those with adjustable load crossbeams and non-round logs, while protecting sensors from external damage.
Implementation Method 1
a deflection gauge attached on a surface of at least one of the bogie arms for detecting the magnitude of a deflection of the bogie arm due to loading of the same with the payload on the forest machine
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The invention relates to a forest machine for transport of payload in forest terrain, comprising a frame (9) on which a payload holding device (3, 4) is mountable, which is adapted to hold the payload (2), a drive unit (8) for driving the forest machine, at least six wheels (10) of which at least four are arranged in form of a bogie (11, 12) comprising two bogie arms (13), which each carries two or more rotatable wheels, are positioned on each side of the forest machine with a longitudinal axis in the driving direction of the forest machine and are via a pivot joint (14) pivotal connected to the frame in an area between the at least two wheels. The forest machine is provided with a payload weighing device for detecting the weight of the payload on the forest machine which comprises at least one deflection gauge (15) attached on a surface of at least one of the bogie arms for detecting the magnitude of a deflection of the bogie arm in an angle of 20-70° in relation to a longitudinal axis of the bogie arm. The invention also relates to a method for payload weighing on a forest machine.