Wiper Blade Plastic Sheathing Ultrasonic Welding

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Solution Overview

Problem

Existing wiper blades face issues with incorrect welding of engagement elements on longitudinal strips during the welding process, leading to potential slippage and instability in the connection between the wiper strip and support rails.

Innovation Solution

A wiper blade design featuring a plastic sheathing with two thermoplastic materials, where one material has a higher melting point and the other a lower melting point, allowing for precise and stable welding exclusively in predetermined positions using ultrasonic welding, preventing the higher melting point material from melting during the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single thermoplastic material is used in the plastic sheathing, then the welding process is simple, but welding can occur at incorrect positions leading to slippage and connection instability

Engineering Contradiction:
Improvewelding process simplicityVSAvoidwelding position accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The plastic sheathing is designed with different material properties in different regions: the first region contains a first thermoplastic material with a higher melting point that provides structural integrity, while the second region contains a second thermoplastic material with a lower melting point that enables controlled welding. This local differentiation allows welding to occur only at predetermined positions where the second material is present, preventing incorrect welding while maintaining manufacturing simplicity.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the melting point of the thermoplastic material is lowered to facilitate welding, then welding becomes easier, but the structural integrity of the plastic sheathing is compromised

Engineering Contradiction:
Improvewelding easeVSAvoidplastic sheathing integrity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The plastic sheathing is constructed as a composite structure with two different thermoplastic materials. The first thermoplastic material has a higher melting point and provides the structural strength and integrity of the sheathing, while the second thermoplastic material has a lower melting point and is specifically positioned in the connection area to enable welding. This composite approach allows the sheathing to maintain its structural integrity while facilitating easy welding at predetermined locations.

Inventive Principle:
Principle #40Composite materials

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

Ensures a secure, reliable, and cost-effective connection between the support rail and base connection device, preventing incorrect welding and enhancing the stability of the wiper blade assembly.

Implementation Method 1

the second thermoplastic is assigned a second melting point, which is lower than the first melting point. When the second thermoplastic material melts, the first thermoplastic material can be safely and reliably prevented from melting.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the support rail is welded to the base connection device in the predetermined connection area by ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Implementation Method 3

The plastic sheathing has a first and a second thermoplastic, the second being provided at least in a predetermined connection area. The first thermoplastic is assigned a first melting point and the second thermoplastic is assigned a second melting point, which is lower than the first melting point.

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2555953B1Wiper blade for a windshield wiper
Publication Date: 2016.11.23 ROBERT BOSCH GMBH
  • EP2555953B1 patent drawingFigure 1
  • EP2555953B1 patent drawingFigure 2~3
  • EP2555953B1 patent drawingFigure 4

AI summary

In a wiper blade (100) for a windshield wiper, having a wiping strip (112) on which there is arranged at least one supporting rail (214) which has a spring element (215) provided with a plastic sheath (217), wherein the plastic sheath (217) is welded, at least in a predefined connecting region (180), to a base connecting device (160) which comprises thermoplastic material having a predefined melting point, the plastic sheath (217) comprises at least a first and a second thermoplastic material.