Insulated Band Clamp Coating for Contact Corrosion Resistance

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Solution Overview

Problem

Conventional band clamps made of stainless steel used for attaching cable shielding to aluminum components risk contact corrosion, and their coatings often detach during assembly or operation, losing their corrosion-inhibiting effect.

Innovation Solution

A band clamp made of CrNi steel with a robust polymer coating, such as Parylene HT, and a Zn layer with a passivating Zn oxide layer, topped with a synthetic resin layer, ensuring the coating remains intact during deformation and high temperatures, preventing contact corrosion with aluminum shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer coating is applied to prevent contact corrosion, then corrosion protection is improved, but the coating may detach during plastic deformation and high temperatures

Engineering Contradiction:
Improvecorrosion protectionVSAvoidcoating integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies a multi-layer composite coating system consisting of a polymer base layer (such as polyolefin or polyester) combined with a metal oxide layer (such as aluminum oxide or zinc oxide). This composite structure provides both corrosion protection and thermal stability, with the metal oxide layer anchoring the polymer to the steel substrate and preventing detachment during deformation and high-temperature operations.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the coating parameters by controlling the thickness, cross-linking density, and thermal treatment of the polymer coating. By optimizing these parameters, the coating maintains its protective function while withstanding the mechanical stresses and thermal conditions encountered during clamp assembly and service.

Inventive Principle:
Principle #35Parameter changes

2Force

If the ear is narrowed with a tool to tighten the clamp, then clamping force is improved, but the coating may detach due to high plastic deformation

Engineering Contradiction:
Improveclamping forceVSAvoidcoating integrity
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent applies a pre-treatment to the steel substrate before coating, such as phosphating or blast cleaning, which creates a surface structure that mechanically interlocks with the coating. This preliminary action ensures that even under high plastic deformation during ear narrowing, the coating remains anchored to the substrate and does not detach.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The multi-layer composite coating system with metal oxide intermediate layer provides enhanced adhesion to the steel substrate, allowing the clamp to withstand the high plastic deformation required for tightening without coating detachment.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a thick coating is applied to ensure complete coverage, then corrosion protection is improved, but the clamp's elasticity and function may be impaired

Engineering Contradiction:
Improvecorrosion protectionVSAvoidelasticity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent optimizes the coating thickness parameter to a specific range (typically 5-20 micrometers total thickness) that provides sufficient corrosion protection while maintaining the elastic properties of the steel clamp. The coating is applied as a thin conformal layer that follows the clamp's deformation without impeding its mechanical function.

Inventive Principle:
Principle #35Parameter changes

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 provides a durable corrosion-inhibiting coating that withstands plastic deformation and high temperatures, maintaining its effectiveness throughout the band clamp's operation, preventing corrosion between the clamp and the cable shield.

Implementation Method 1

a Zn layer with a passivating Zn oxide layer

Methodology Applied
Scientific EffectPassivation: Oxidation

Implementation Method 2

The polymer coating withstands high operating temperatures and allows strong plastic deformations, even on the ear-shaped clamping device, without detaching from the band clamp

Methodology Applied
Scientific EffectThermal stability: Thermal Expansion

Implementation Method 3

Parylene, in particular Parylene HT, has proven particularly suitable as a polymer material, which is preferably vapor-deposited from the gas phase onto the degreased band clamp in a vacuum chamber

Methodology Applied
Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentEP3977567B1Band clamp and method of production thereof
Publication Date: 2024.06.05 OETIKER SCHWEIZ AG

AI summary

The invention relates to a band clamp having an insulating coating, for fastening the shielding of a cable, which has a conductor, an insulation surrounding same and an outer shielding. Measures are taken to make the coating robust and durable and to avoid contact corrosion on the shielding and the band clamp.