Tree Processing Head Saw Bar Position Detection via Hydraulic Pressure
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Solution Overview
Problem
Operators of tree processing systems face challenges in cutting trees efficiently due to blind spots created by bar saw and grapple saw heads, which require extended operation time and manual intervention to ensure complete stem separation without visibility of the saw bar's position.
Innovation Solution
A tree processing system incorporating a controller, motor, saw bar, arm, actuator, and sensors that detect hydraulic pressure changes to determine the completion of cutting positions, allowing for automated operation and reduced unnecessary cutting cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a bar saw felling head or grapple saw head is used to cut trees, then the cutting operation can be performed, but the head obstructs the operator's vision of the tree cutting area creating a blind spot
Solution Approach 1:
A camera is introduced as an intermediary device mounted on the tree processing head to capture images of the cutting area. These images are transmitted to a display device in the operator cab, allowing the operator to see the cutting area despite the head obstructing direct vision. This mediator bridges the gap between the cutting tool and the operator's line of sight.
2Reliability
If the operator waits for the saw bar to become visible on the opposite side of the tree to ensure complete stem cutting, then cutting completeness is ensured, but the cutting cycle time is extended
Solution Approach 1:
A sensor detects the position of the saw bar during the cutting operation and provides feedback signals to the controller. When the sensor detects that the saw bar has reached the predetermined second position (indicating complete stem separation), the controller automatically stops the cutting operation. This feedback mechanism eliminates the need for the operator to wait for visual confirmation, reducing cutting cycle time while ensuring complete cuts through automated position monitoring.
3Reliability
If the saw bar is commanded to travel through the entire tree to ensure complete separation, then stem separation is achieved, but the operation time is longer than desired
Solution Approach 1:
The system is configured with a predetermined second position that is established before the cutting operation begins. The sensor and controller are programmed to recognize when the saw bar reaches this predetermined position, allowing the system to stop the cutting operation as soon as complete stem separation is achieved, rather than requiring the saw bar to travel through the entire tree. This preliminary setup of stop positions optimizes the cutting path and reduces unnecessary travel time.
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 shortens the cutting cycle, eliminates dry run cycles, and improves productivity by enabling the tree processing head to operate efficiently even when the saw bar is not visible, thus enhancing the cutting operation's effectiveness.
Implementation Method 1
The sensor is configured to detect a hydraulic pressure of at least one of the motor and the actuator
Data Source
AI summary
A method for a tree processing head to harvest a tree includes initiating a cutting operation on a tree, the cutting operation including powering a cutting chain of a saw bar driven by a motor; securing the tree; moving the saw bar via an actuator, the saw bar configured to be moved from a home position to a first position and to a second position, and the first position and the second position defining a cutting zone; detecting a hydraulic pressure of at least one of the motor and the actuator by a sensor; determining whether the second position is reached based upon a decrease of the hydraulic pressure by a controller; and transmitting a resting signal to the tree processing head to perform a resting operation when the controller determines that the second position is reached.