Extendable Tensioning Device for Power Line Ice Load Management

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Solution Overview

Problem

Existing power line protection systems face challenges in managing excessive weight from ice or snow, which can lead to cable detachment or support collapse, as they rely on a disc sliding mechanism that may not effectively distribute the weight and provide controlled stiffness.

Innovation Solution

A piston sliding within a tubular body with an annular element and radial hook mechanism, utilizing two elastic means to control the rod's movement and provide a flexible, separable connection, allowing the cable to flex and twist under weight without compromising the support structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a disc sliding mechanism is used to allow cable flexing under snow or ice weight, then the cable can flex and twist without causing support failure, but the mechanism does not effectively distribute the weight and provide controlled stiffness

Engineering Contradiction:
Improveprevention of support collapseVSAvoidinsufficient weight distribution capability
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The disc is segmented into multiple radial hooks that can independently engage with notches on the rod, allowing the weight to be distributed across multiple engagement points. This segmentation enables better load distribution while maintaining the flexing capability of the device.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device transitions from a static disc to a dynamic system where hooks can engage and disengage from notches based on the applied load. This dynamic behavior allows the device to provide controlled stiffness by engaging at specific load thresholds while still allowing cable movement, resolving the contradiction between reliability and weight distribution.

Inventive Principle:
Principle #15Dynamics

2Strength

If a fixed connection is used between the rod and annular element, then the structure provides rigid support, but it cannot allow the cable to flex and twist under excessive weight

Engineering Contradiction:
Improvestructural rigidityVSAvoidflexibility under load
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The connection between the rod and annular element is made dynamic through the hook-notch engagement mechanism. The hooks can engage with notches to provide rigid support under normal conditions, and disengage when the load exceeds a certain threshold, allowing the cable to flex and twist. This dynamic connection resolves the contradiction between structural rigidity and flexibility under load.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hooks act as intermediaries between the rigid rod and the flexible cable. They transmit force when engaged, providing structural rigidity, and can disengage to allow flexibility when needed. This intermediary mechanism enables the system to adapt between rigid and flexible states based on load conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If a single elastic means is used to push the rod back after snow falls, then the device returns to initial condition, but it cannot provide controlled stiffness during the extension and retraction process

Engineering Contradiction:
Improveautomatic return to initial positionVSAvoidlack of controlled stiffness
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The elastic means is segmented into two separate elastic elements: a first elastic means that pushes the rod outward when the cable is pulled, and a second elastic means that pushes the rod back inward after the load is removed. This segmentation allows each elastic element to be optimized for its specific function and provides controlled stiffness during both extension and retraction phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual elastic means system creates a dynamic stiffness characteristic where the device is stiff during normal operation, becomes flexible under excessive load, and returns to its initial state with controlled stiffness during retraction. This dynamic behavior provides the necessary controlled stiffness while maintaining automatic return functionality.

Inventive Principle:
Principle #15Dynamics

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 effectively manages excessive weight by allowing the cable to flex and twist, reducing the risk of detachment and support failure, while maintaining controlled stiffness and preventing damage from fixed connections, applicable in various contexts beyond power lines.

Implementation Method 1

a first elastic means (20), housed inside the external cylindrical body (10) and adapted to push said piston (18) toward said first retracted position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a second elastic means (28), housed inside the external cylindrical body (10) and interposed between said annular element (26) and a projection (19b) integral with said rod (19), the opposite end (28b) of said second elastic means (28) abutting against said projection (19b), said second elastic means (28) being adapted to push said rod (19) toward said first retracted position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The rod (19) is slidably housed in the annular element (26)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3905463B1Extendable tensioning device, in particular for protecting overhead power lines
Publication Date: 2023.02.22 TENESA SRL
  • EP3905463B1 patent drawingFigure 1
  • EP3905463B1 patent drawingFigure 2
  • EP3905463B1 patent drawingFigure 3

AI summary

A device for the protection of power lines, an external cylindrical body (10), which may be hooked to a support, a piston (18), slidably housed inside the external cylindrical body (10) and which may be rotatably translated between a first retracted position and a second extended position, and two elastic means (20, 28), between which an annular element (26) is interposed, coaxial with respect to the rod, said annular element (26) housing at least one hook (30), integral with the annular element (26) and radially movable between an engaged condition with a corresponding recess (33) on the rod (19), wherein the rod (19) is not free to slide with respect to the annular element (26), and a disengaged condition from the recess (33), wherein the rod (19) is free to slide with respect to the annular element (26).