Forestry Winch Cable Coiling Control via Rotating Pulleys
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Solution Overview
Problem
Existing forestry winches face issues with controlled coiling of towing cables, leading to overlapping and overloading due to high friction and inertia, which can result in cable damage and instability during heavy load towing.
Innovation Solution
A forestry winch design featuring a directing assembly with rotatable pulleys and a dynamometer to guide the towing cable onto the winding drum, ensuring controlled coiling and preventing overloading by dynamically adjusting the cable path and measuring tension forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a motor-driven upper pulley block is used to decoil the towing cable, then the force required for decoiling is reduced, but the cable may deflect away from the desired direction and concentrate in the central region of the winding drum, leading to overlapping windings
Solution Approach 1:
A directing assembly with two freely rotatable pulleys is introduced as an intermediary between the upper pulley block and the winding drum. This directing assembly guides the cable section from the upper pulley block along the vertical axis and then redirects it tangentially towards the winding drum surface, preventing cable concentration in the central region and ensuring proper side-by-side coiling arrangement.
Solution Approach 2:
The directing assembly changes the cable's path from a direct radial approach to the drum center to a tangential approach along the drum surface. By introducing the vertical axis dimension and tangential redirection, the cable is guided to wrap around the drum periphery rather than concentrating at the center, achieving proper coiling geometry.
2Ease of operation
If the towing cable is coiled in the central region of the winding drum, then decoiling is easier, but overlapping windings occur which increase tension loadings and may damage the cable
Solution Approach 1:
The directing assembly acts as a mediator that redirects the cable from a central coiling path to a peripheral coiling path. The two freely rotatable pulleys guide the cable tangentially to the drum surface, ensuring windings are arranged side by side without overlapping, thereby reducing tension loadings and preventing cable damage while maintaining operational ease.
3Device complexity
If the upper pulley block is fixed in position, then the structure is simpler, but the cable path cannot be dynamically adjusted to maintain proper coiling direction
Solution Approach 1:
The directing assembly is made dynamically adjustable through two freely rotatable pulleys that can rotate around their horizontal axes. This dynamic capability allows the cable path to be automatically adjusted as the cable coils or decoils from different positions on the drum, maintaining proper alignment and preventing overlapping windings without requiring a complex movable upper pulley block structure.
4Manufacturing precision
If a directing assembly with freely rotatable pulleys is added to guide the cable, then proper coiling is achieved, but the device complexity increases
Solution Approach 1:
The two pulleys in the directing assembly are freely rotatable and self-adjusting, automatically orienting themselves to guide the cable along the correct path without requiring external actuators or complex control mechanisms. This self-service capability achieves precise cable coiling guidance while minimizing the addition of complex actuated components.
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 ensures side-by-side coiling of the towing cable without overlapping, reducing tension loads and preventing cable damage by dynamically adjusting the cable path and monitoring tension forces, thereby enhancing the winch's stability and durability during heavy load towing.
Implementation Method 1
a dynamometer, which is adapted for measuring of tension forces in the towing cable
Implementation Method 2
a directing assembly which is furnished with two pulleys, which are each per se freely rotatable around their rotational axles
Data Source
Figure 1~2
AI summary
The purpose of the invention is to create a forestry winch suitable for attachment to a tractor, by which coiling of a towing cable (2) should be performed in a controlled manner, which means that each disposable windings of said cable (2) on the surface of a winding drum (1) should be arranged side by side relatively to each other and without any transpositioning or overlapping, and that each overloading of said towing cable (2) and other components of a driving assembly due to towing of too heavy load should be excluded. To this aim, the winch is furnished-with-a-directing assembly (4), which is arranged between an upper pulley block (3) and said winding drum (1) and is freely rotatable or least pivotable at certain angle around the vertical geometric axis (40), wherein said winch moreover includes a dynamometer (46) suitable for measuring of tensioning force (F) within said towing cable (2), so that also the winding drum (1) can be controlled depending on each measured loading of the towing cable (2).