Felling Head Hydraulic Sequencing for Controlled Timber Deposition
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Solution Overview
Problem
Existing timber harvesting devices with hydraulically controlled felling heads suffer from uncontrolled pivoting of the tilting device into the depositing position due to gravity after cutting, leading to operational inefficiencies.
Innovation Solution
A hydraulic control system utilizing two hydraulic lines for precise positioning and pivoting of the gripper and saw unit, incorporating non-return valves and pressure sequencing to maintain the tilting device in the cutting position until the cutting process is complete, and then allowing controlled pivoting into the depositing position using the second hydraulic line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the tilting device is actuated by gravity after cutting, then the device can automatically return to depositing position, but the pivoting becomes uncontrolled and imprecise
Solution Approach 1:
The patent uses a hydraulic system with a second hydraulic line to control the tilting device. By pressurizing the second hydraulic line, the tilting device can be controlled to pivot from cutting position to depositing position in a controlled manner, replacing the uncontrolled gravity-based movement while maintaining ease of operation through hydraulic actuation.
2Productivity
If the cutting element is activated by pressurizing the second hydraulic line, then cutting function is enabled, but the tilting device cannot be controlled to pivot to depositing position simultaneously
Solution Approach 1:
The patent introduces a pressure range threshold mechanism where the second hydraulic line operates at different pressure levels. When pressure exceeds a first threshold, the cutting element is activated. When pressure is within a controlled range below the threshold, the tilting device can pivot to the depositing position. This parameter-based control allows selective activation of different functions based on hydraulic pressure level.
Solution Approach 2:
The patent uses a hydraulic control system with sequencing valves as an intermediary between the operator's control inputs and the actual actuation of cutting and tilting functions. The sequencing valves mediate the hydraulic flow to ensure that cutting and tilting operations are properly sequenced and controlled, preventing simultaneous conflicting operations while maintaining operational efficiency.
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
Enables controlled and precise positioning of the felling head during timber harvesting, preventing unintentional movement and ensuring accurate placement of cut timber.
Implementation Method 1
the tilting device can be pivoted from its cutting position into its depositing position by pressurizing the second hydraulic line in a pressure range in which the cutting element remains in an inactive state
Implementation Method 2
The cutting element is designed as a chainsaw and is usually pivotably mounted in a saw box, wherein it can be put into operation using a hydraulic motor arranged in the saw box
Data Source
AI summary
Device for timber harvesting having a felling head which includes a gripper and saw unit and a tilting device. The gripper and saw unit have gripper arms which can be actuated by a first hydraulic cylinder and a cutting element which can be pivoted out by a second hydraulic cylinder, and can be pivoted from a depositing position into a cutting position for the harvested material with the aid of the tilting device, which can be actuated by a third hydraulic cylinder. The first hydraulic cylinder is connected to a first hydraulic line for opening the gripper arms and to a second hydraulic line for closing the gripper arms. The tilting device can be pivoted from its cutting position into its depositing position by pressurizing the second hydraulic line in a pressure range in which the cutting element remains in an inactive state.