Universal Carriage Enforced Traction Cable Spooling

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Solution Overview

Problem

Cable cranes in forestry face challenges with manual spooling of traction cables, especially with high tensile forces required, and existing carriages are heavy, prone to engine damage, and limited in spooling length and speed due to high motor power and gear reductions.

Innovation Solution

A carriage with an auxiliary cable drum connected to a friction disk and driven by both an electric motor and the auxiliary cable, allowing for reliable forced spooling of the traction cable in both 2-rope and 3-rope operations, enabling flexible operation on various slopes and loads with reduced weight and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual spooling of the traction cable is used, then the carriage structure is simple, but the spooling work is strenuous and impossible with high tensile forces

Engineering Contradiction:
Improvespooling operationVSAvoidtensile force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent replaces manual mechanical spooling with a motor-driven spooling system. The motor (electric, hydraulic, or pneumatic) provides the necessary torque to unwind the traction cable from the carriage, eliminating the need for manual effort while handling high tensile forces that would be impossible for human operators to manage directly.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a motor as an intermediary device between the operator's control and the traction cable spooling operation. The motor acts as a mediator that converts electrical, hydraulic, or pneumatic energy into mechanical rotation to spool the cable, bridging the gap between control and the high-force physical operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If a diesel engine or diesel-hydraulic winch is used for spooling, then high spooling force is achieved, but the carriage becomes very heavy and the engine is prone to damage when tilted

Engineering Contradiction:
Improvespooling forceVSAvoidcarriage weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent replaces diesel engines with alternative drive systems such as electric motors, hydraulic motors, or pneumatic motors. These alternatives provide comparable spooling force without the weight and tilt-sensitivity issues of combustion engines, reducing overall carriage weight while maintaining the necessary mechanical output for cable spooling.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters of the spooling system by transitioning from combustion-based power (diesel) to alternative energy conversion methods (electric, hydraulic, pneumatic). This parameter change allows achieving the same spooling force with different physical characteristics, specifically lower weight and better performance under tilted conditions.

Inventive Principle:
Principle #35Parameter changes

3Force

If high motor power and gear reductions are used for spooling, then sufficient spooling force is achieved, but the spooling length and speed are significantly limited

Engineering Contradiction:
Improvespooling forceVSAvoidspooling speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The patent employs dynamic control of the spooling system, allowing the motor to operate in different modes depending on the required output. The system can provide high torque at low speeds when force is needed, and transition to higher speeds when cable payout is the priority, optimizing both spooling force and speed throughout the operation cycle rather than being constrained by fixed gear ratios.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes periodic variation in spooling operation, alternating between high-force phases and high-speed phases. The control system modulates motor power delivery to provide bursts of high torque when cable tension is required, followed by higher-speed operation when force requirements are reduced, achieving both force and speed objectives through temporal separation of functions.

Inventive Principle:
Principle #19Periodic action

4Force

If the auxiliary cable is used to unwind the traction cable in 3-cable operation, then the spooling force is sufficient, but the laying of the auxiliary rope is time-consuming

Engineering Contradiction:
Improvespooling forceVSAvoidtime for laying auxiliary rope
Core Design Contradiction:
ForceVSLoss of time

Solution Approach 1:

The patent designs the motor-driven spooling system to perform multiple functions: it can spool the traction cable during both 2-cable and 3-cable operations, eliminating the need for separate manual or cable-based spooling mechanisms. The same motor system that provides sufficient spooling force also eliminates the time-consuming auxiliary cable laying process by directly powering the spooling operation in all operational modes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent extracts the spooling function from the auxiliary cable system and consolidates it into a dedicated motor-driven mechanism. By removing the dependency on auxiliary cable laying for spooling operations, the system eliminates the time-consuming cable deployment step while maintaining sufficient spooling force through direct motor power.

Inventive Principle:
Principle #2Taking out (Extraction)

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 reliable and efficient spooling of traction cables in all modes of operation, reducing weight and energy consumption, and allowing for longer spooling lengths with the option to switch between motor-driven and auxiliary cable-driven spooling, ensuring consistent performance regardless of the carriage's position.

Implementation Method 1

a friction disk, which is provided for the unwinding movement of the traction rope

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3810541B1Universal carriage with enforced spooling out of the traction cable and/or of the hoisting cable in 2- and 3-cable operation
Publication Date: 2023.01.25 MM FORSTTECHN GMBH
  • EP3810541B1 patent drawingFigure 1~3
  • EP3810541B1 patent drawingFigure 4~5
  • EP3810541B1 patent drawingFigure 6~7

AI summary

Universal carriage (2; 20) of a cable crane (1) for transporting loads along a load-bearing cable (5) of the cable crane (1), wherein the carriage (2; 20), which is pulled along the load-bearing cable (5) of a yarder (6) of the cable crane (1), in 2-cable operation by a traction cable (3), and in 3-cable operation, in addition by an auxiliary cable (7), has a motor for spooling out the traction cable (3) or a hoisting cable (26) from the carriage (2) and also has a friction disc (13), which is provided for the spooling-out movement of the traction cable (3), and/or a hoisting-cable drum (22), which is provided for the spooling-out movement of the hoisting cable (26), and is driven directly or indirectly by the motor, wherein the carriage (2; 20) has an auxiliary-cable drum (15; 24) for spooling out the auxiliary cable (7) in 3-cable operation, and the auxiliary-cable drum (15; 24) is in operative connection with the friction disc (13) and/or the hoisting-cable drum (22) and, driven by the auxiliary cable (7), is provided in addition, or as an alternative, to the motor for spooling out the traction cable (3) and/or the hoisting cable (26).