Electric Heating Wedge With Metal Support Structure

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Solution Overview

Problem

Ceramic electric hot wedges used for welding plastic webs are prone to breakage and lack a variably adjustable temperature profile, leading to issues like wave-like deformations in weld seams and poor heat distribution.

Innovation Solution

An electric heating wedge with a metal lateral support structure that stabilizes the ceramic heating resistor, featuring a direct integration of the heating resistor within the welding wedge for improved heat distribution and a variably adjustable temperature profile through multiple heating zones with independently controlled heating resistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If ceramic material is used for the welding wedge to improve abrasion resistance and corrosion resistance, then the service life is extended, but the mechanical stability and resistance to breakage deteriorates

Engineering Contradiction:
Improveservice lifeVSAvoidmechanical stability
Core Design Contradiction:
Duration of action of stationary objectVSStrength

Solution Approach 1:

The patent employs a composite structure combining ceramic material with a metal support grid. The ceramic provides abrasion and corrosion resistance for extended service life, while the embedded metal grid reinforces mechanical stability and prevents breakage. This composite approach allows simultaneous achievement of both durability and structural integrity.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If a single temperature zone is used in the welding wedge, then the device complexity is reduced, but the welding quality for different plastic materials deteriorates due to wave-like deformations

Engineering Contradiction:
Improvetemperature zone configurationVSAvoidwelding quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The welding wedge is divided into multiple independent temperature zones along its length, each with independently controllable heating resistors. This segmentation allows different sections to operate at different temperatures optimized for specific plastic materials, eliminating wave-like deformations and improving welding precision without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each temperature zone is equipped with independently controllable heating elements, allowing local temperature adjustment according to the specific welding requirements of different plastic materials. This local quality control enables precise temperature management in different regions of the welding wedge.

Inventive Principle:
Principle #3Local quality

3Power

If metal heating cartridges are embedded in the welding wedge, then the heating efficiency is improved, but the heat distribution becomes non-uniform and heating time increases

Engineering Contradiction:
Improveheating efficiencyVSAvoidheat distribution uniformity
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The patent extracts the heating elements from traditional embedded metal cartridges and reconfigures them as surface-mounted resistive heating elements distributed across the welding wedge surface. This extraction allows for more uniform heat distribution across multiple zones while maintaining heating efficiency, and enables independent control of each heating zone.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If the ceramic heating resistor is used without metal support, then the purity of heating function is maintained, but the risk of breakage in rough operation increases significantly

Engineering Contradiction:
Improveheating function simplicityVSAvoidresistance to breakage
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent combines ceramic heating resistor material with an embedded metal support grid structure. The ceramic maintains its superior heating properties and chemical inertness, while the metal grid provides mechanical reinforcement to prevent breakage during rough operation. This composite construction preserves the heating function's purity while dramatically improving reliability.

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

The solution enhances the mechanical stability of ceramic heating elements, ensures rapid and even heat distribution, and allows for precise temperature control, reducing the risk of breakage and improving weld quality by minimizing wave-like deformations.

Implementation Method 1

the plastic webs are plasticized at their contact surfaces by means of the hot wedge... heated by cylindrical electric heating cartridges... to heat it to a temperature above the melting temperature of the plastic webs

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an electric heating wedge for a welding device... with a welding wedge and a welding wedge suspension, the welding wedge having at least one electric heating resistor with a heating conductor which is applied as a conductive layer in a materially bonded manner to a ceramic carrier

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2247433B1Electric heating wedge
Publication Date: 2016.03.23 LEISTER TECHNOLOGIES AG
  • EP2247433B1 patent drawingFigure 1~2b
  • EP2247433B1 patent drawingFigure 3a~4b
  • EP2247433B1 patent drawingFigure 5a~6b

AI summary

The invention relates to an electric hot wedge (1) for a welding device for the seam-like connecting of plastic webs, having a welding wedge (2) and a welding wedge attachment (3) made of metal, wherein the welding wedge (2) comprises at least one electric heating resistor (13) having a heating conductor (16), which is bonded to a ceramic carrier (15) as a conductive layer (12) and is preferably protected by a ceramic cover layer. According to the invention, the welding wedge attachment (2) has a support structure (28) made of metal on the side thereof, which substantially extends across the entire length and/or width of the electric heating resistor (16) and which mechanically stabilizes the carrier (15) of the heating resistor (16).