Movable Die Cable Sheathing for Constant Diameter

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Solution Overview

Problem

Existing cable sheathing devices face challenges in maintaining a constant sheath diameter when wire speed increases, requiring high pressure adjustments and complex regulation systems to compensate for the speed effect, which is particularly problematic for achieving thin sheaths and high-speed operations.

Innovation Solution

A device with a movable die that adjusts its position relative to the central chamber and outlet die, allowing the material to flow through either the movable die at low speeds or the outlet die at high speeds, maintaining a constant sheath diameter by regulating pressure within a smaller range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the pressure in the central chamber is increased to maintain constant sheath section at high speeds, then the sheath diameter remains constant, but the device complexity and cost increase due to the need for high pressure regulation systems

Engineering Contradiction:
Improvesheath diameter consistencyVSAvoidpressure regulation system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The die is made mobile rather than fixed, allowing it to change position dynamically based on wire speed. At low speeds, the die is positioned downstream to provide calibration; at high speeds, it moves upstream to reduce its constraining effect, thereby maintaining constant sheath diameter without requiring complex high-pressure regulation systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The calibration section of the die is changed by moving the die between two positions. The effective calibration section varies from S1 (when die is downstream) to S2 (when die is upstream), allowing the system to adapt to different wire speeds and maintain manufacturing precision without increasing pressure regulation complexity

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the wire speed is increased to improve productivity, then the production rate increases, but the sheath diameter decreases due to material entrainment effects

Engineering Contradiction:
Improvewire processing speedVSAvoidsheath diameter consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The die position is dynamically adjusted according to wire speed. When wire speed increases, the die moves upstream away from the central chamber, reducing its calibration effect and compensating for the material entrainment that would otherwise cause sheath diameter reduction. This allows high productivity while maintaining manufacturing precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses wire speed as feedback to control die position. The actuator receives signals about the wire speed and automatically adjusts the die position accordingly, creating a closed-loop control system that maintains constant sheath diameter across varying production rates

Inventive Principle:
Principle #23Feedback

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 sheathing over a high-speed range with a substantially constant sheath thickness, reducing the need for high pressure adjustments and increasing the complexity and cost of regulation systems, while being particularly effective for producing thin sheaths.

Implementation Method 1

a central chamber connected by a conduit to an extrusion means capable of delivering a material under pressure plastic or thermoplastic in the viscous state

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Implementation Method 2

the wire drives the sheathing material towards the outlet die, the calibration section of which gives the wire the shape of its final section

Methodology Applied
Scientific EffectEntrainment: Entrainment

Data Source

PatentEP1882578B1Apparatus and method for sheathing of cables and the manufactured cable
Publication Date: 2009.09.09 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP1882578B1 patent drawingFigure 1
  • EP1882578B1 patent drawingFigure 2
  • EP1882578B1 patent drawingFigure 3~7

AI summary

Device for sheating wires with plastic, comprising a wire guide (2) opening into a central chamber (51) connected to an extruder, a wire exit die (4) and a moving die (12) of smaller cross-section than the wire exit die, comprises an actuator (13) that traverses the central chamber and moves the moving die in the wire advancement direction and has an opening for connecting the central chamber to the inside of the moving die. Independent claims are also included for: (1) sheathing wires using a device as above, where the moving die is located between the central chamber and the wire exit die when the wire speed is low and is moved upstream of the central chamber when the wire speed is high; (2) pneumatic tire comprising a sheathed wire produced as above.