Gravity-Activated Drum Brake for Railway Tension Compensation

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Solution Overview

Problem

Existing tension compensation devices for cable messenger wires and contact wires in electrified railway power supply systems are complex, costly, and prone to safety hazards due to high mounting positions, damage from unauthorized access, and inadequate braking mechanisms, especially in tunnels and bridges.

Innovation Solution

A tension compensation device with a simple structure featuring a hollow cylindrical shell, a rope wheel with a cylindrical or conical groove, and a gravity-activated brake mechanism using friction, clamping, or pawl engagement to trigger the brake function upon cable fracture, ensuring reliable operation and low costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional tension compensation device is used with high mounting position and weight-bearing rope brake, then the cable tension can be maintained, but the device is vulnerable to unauthorized access damage and has complex structure

Engineering Contradiction:
ImprovesafetyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the brake mechanism from the traditional high-mounted weight-bearing rope system and relocates it to a low-mounted drum brake system integrated into the tension compensation device. This separates the braking function from the tensioning function, allowing the brake to be protected while maintaining simple overall structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a gravity-activated intermediary mechanism where the weight of the tension compensation device itself serves as the braking force through gravitational action on the drum brake. This eliminates the need for separate complex braking systems while ensuring reliable activation upon cable fracture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a weight-bearing rope brake is used to prevent rapid unwinding, then safety is improved, but the mounting position must be very high and the weight is vulnerable to damage

Engineering Contradiction:
ImprovesafetyVSAvoidvulnerability to damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of mounting the brake mechanism at high position with weight-bearing rope, the patent inverts the approach by placing the drum brake at low position and using the device's own weight to activate it. The brake is now protected from unauthorized access while maintaining its safety function.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The tension compensation device uses its own weight as the braking force source. The gravity-activated drum brake automatically engages when the cable fractures, eliminating the need for external weight-bearing ropes that are vulnerable to damage.

Inventive Principle:
Principle #25Self-service

3Reliability

If complex safety locking mechanisms are added to prevent counter-rotation, then safety is improved, but the device complexity and cost increase

Engineering Contradiction:
ImprovesafetyVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the safety braking function with the existing tension compensation mechanism by integrating a drum brake into the device. The brake shares the structural space and gravitational force with the tensioning system, eliminating the need for separate complex locking mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent converts the harmful rapid counter-rotation that occurs upon cable fracture into a beneficial automatic braking action. The sudden release of tension triggers the gravity-activated drum brake, which safely dissipates the kinetic energy through friction rather than causing damage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If traditional brake mechanisms are used, then cable fracture safety is addressed, but they require complex implementation conditions and high cost

Engineering Contradiction:
Improvebrake reliabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a simple drum brake mechanism that can be manufactured at low cost using basic machining operations. The brake lining is a replaceable consumable component that can be easily replaced when worn, eliminating the need for expensive complex braking systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 device effectively implements a brake function through a low-cost, reliable, and widely applicable mechanism that prevents rapid unwinding and potential accidents by shifting the center of gravity to trigger the brake, enhancing safety and usability.

Implementation Method 1

a brake component arranged on the drum, which is in a brake engagement state with the drum under the action of gravity

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the brake component arranged on the drum, which is in a brake engagement state with the drum under the action of gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2514629B1Tension compensation device with brake function
Publication Date: 2016.09.14 KERN LIEBERS TAICANG
  • EP2514629B1 patent drawingFigure 1~3
  • EP2514629B1 patent drawingFigure 4~5
  • EP2514629B1 patent drawingFigure 6~7

AI summary

The invention relates to a tension compensation device with brake function, which at least comprises a main shaft (10) and a shell (20) rotating relative to each other. One of the main shaft (10) and the shell (20) is used for connecting with a tension part (30). An elastic part is arranged between the main shaft (10) and the shell (20) so as to provide a torque therebetween, which reacts on the tension part (30). The tension compensation device also comprises a brake mechanism in whole or in part. When the tension compensation device fails due to the fracture of the tension part (30), the brake mechanism will be triggered by gravity to implement the brake function. The tension compensation device uses the gravity to trigger the brake mechanism, and implements the brake function at low cost, and has the advantages of simple structure, high reliability, a wide range of applications and the like.