Forestry Winch Ejector Pressure Roller for Plastic Cable
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Solution Overview
Problem
Existing ejectors for forestry winches with steel cables are not suitable for plastic cables, resulting in poor force transmission and slippage, which can damage the plastic cable and impose high load-bearing forces on operators.
Innovation Solution
A rotatable pressure roller driven by a motor is used to press the plastic cable onto a steel ejector roller, transmitting axial forces and achieving sufficient tension without actively driving the ejector roller, allowing for low operating forces and reduced wear on the plastic cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a steel ejector roller is used with a plastic cable, then the ejector roller can be designed as a stable steel roller for deflecting the cable, but the pairing results in very poor force transmission values and slippage that can damage the plastic cable
Solution Approach 1:
A pressure roller made of rubber or rubber-like material is introduced as an intermediary between the steel ejector roller and the plastic cable. The pressure roller is driven by a drive motor and presses the plastic cable onto the steel ejector roller, providing good force transmission while the steel roller maintains structural stability and serves as a deflection roller. This mediator resolves the contradiction by enabling effective force transmission without requiring the ejector roller itself to be made of soft material.
2Force
If the ejector roller is actively driven by a drive motor to transmit axial forces to the plastic cable, then sufficient cable tension can be achieved, but the poor force transmission between steel roller and plastic cable results in slippage and cable damage
Solution Approach 1:
The pressure roller made of rubber or rubber-like material serves as a mediator that is driven by the drive motor to press the plastic cable onto the steel ejector roller. This intermediary provides the necessary friction and force transmission to the plastic cable without causing slippage, while the steel ejector roller remains undriven and serves only as a stable deflection surface.
Solution Approach 2:
The material parameter of the pressure roller is changed to rubber or rubber-like material, which has different friction characteristics compared to steel. This parameter change enables effective force transmission to the plastic cable while preventing slippage and damage, resolving the contradiction between achieving sufficient axial force and avoiding harmful slippage effects.
3Strength
If a steel cable is used in the forestry winch, then sufficient strength and cable tension can be achieved, but the high dead weight causes high load-bearing forces for the operator to carry the cable
Solution Approach 1:
The material of the cable is changed from steel to plastic, fundamentally altering the weight parameter while maintaining sufficient strength for the application. The plastic cable significantly reduces the dead weight and load-bearing forces for the operator, while the ejector system with the driven pressure roller and steel ejector roller provides the necessary force transmission and cable control.
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 design enables efficient transmission of axial forces to the plastic cable, reducing operator load and preventing damage, while maintaining low operating forces and minimizing wear on the cable and ejector components.
Implementation Method 1
the pairing of steel ejector roller and plastic rope results in very poor force transmission values
Implementation Method 2
a desired axial force and thus cable tension can be applied to the steel cable
Data Source
Figure 1
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AI summary
The invention relates to an ejector (6) for a forestry winch (1), wherein the ejector (6) has a rotatable ejector roller (7) over which a plastic rope (4) is guided and deflected. The ejector (6) has at least one rotatable pressure roller (10; 10a; 10b) driven by a drive motor (12), by means of which the plastic rope (4) is pressed against the ejector roller (4).