Domestic appliance having a connecting element

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Solution Overview

Problem

Household appliances, particularly cooking appliances, face issues with corrosion and leaks due to thin support parts that are not suitable for secure fastening, leading to unwanted cracks in enamel coatings and gas escape between attachment surfaces.

Innovation Solution

A connecting element is welded to the supporting part using resistance projection welding, creating a gas-tight seal and providing a stable attachment point, allowing for secure fastening of attachments without requiring additional tools for assembly, and preventing corrosion by forming a circumferential weld seam around the receiving area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thin support parts are used to reduce cost and improve energy efficiency, then manufacturing cost and energy efficiency are improved, but fastening reliability and corrosion resistance deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoidfastening reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The support part is segmented into two functional components: a thin-walled support structure for cost and energy efficiency, and a separate connecting element with increased wall thickness for reliable fastening. The connecting element is welded to the support part, creating a hybrid structure that combines the advantages of both thin and thick-walled designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution uses a composite structure combining thin-walled support parts (for cost efficiency) with thick-walled connecting elements (for mechanical strength). This composite approach allows each component to be optimized for its specific function while working together as an integrated system.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If thin support parts are used, then manufacturing cost is reduced, but enamel coating integrity deteriorates due to cracking under screwing forces

Engineering Contradiction:
Improvemanufacturing costVSAvoidenamel cracking
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The fastening function is segmented from the thin support part and transferred to a separate connecting element. This prevents screwing forces from being applied directly to the thin support part and its enamel coating, eliminating the cracking problem while maintaining cost efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting element acts as an intermediary component between the screw and the thin support part. It absorbs and distributes the mechanical stresses, protecting the enamel coating on the support part from cracking while enabling secure fastening.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a washer with thread is used to transmit screwing forces, then fastening reliability is improved, but assembly complexity increases and gas-tightness deteriorates

Engineering Contradiction:
Improvefastening reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connecting element merges multiple functions into a single component: it provides the threaded receiving area for fastening, the weld surface for secure attachment to the support part, and the sealing surface for gas-tightness. This eliminates the need for separate washers and simplifies assembly.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connecting element is a multi-functional component that simultaneously provides mechanical fastening (threaded area), structural attachment (weld surface), and sealing (contact surface with support part). This universal design replaces multiple separate components with a single integrated element.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If attachments are fastened directly to thin support parts, then device complexity is reduced, but corrosion resistance deteriorates due to enamel cracking

Engineering Contradiction:
Improvedevice complexityVSAvoidcorrosion resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The structure is segmented into the thin support part (maintaining simplicity) and the separate connecting element (providing corrosion resistance). The connecting element's thicker wall prevents enamel cracking and corrosion, while the support part remains simple and cost-effective.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting element serves as an intermediary protective layer between the corrosive environment and the thin support part. It prevents corrosion from reaching the support part while maintaining the overall simplicity of the device design.

Inventive Principle:
Principle #24Intermediary (Mediator)

5Reliability

If connecting element is welded to supporting part, then fastening reliability and corrosion resistance are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvefastening reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical connection between the connecting element and support part is replaced by a welded connection. This substitution provides stronger, more reliable attachment and better corrosion resistance, while the welding process can be automated to minimize manufacturing complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 tightness and corrosion resistance of household appliances, prevents leaks, and simplifies the assembly and replacement of attachments, ensuring a secure and durable connection.

Implementation Method 1

A connecting element receiving the screw is welded to the side of the supporting part opposite the attachment. According to the invention, the connecting element is welded to the supporting part by means of a resistance projection welding process

Methodology Applied
Scientific EffectElectrical resistance heating: Joule Heating

Implementation Method 2

Joining the connecting part with the supporting part by means of welding, preferably resistance projection welding

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3507548B1Domestic appliance having a connecting element
Publication Date: 2020.11.11 BSH HAUSGERATE GMBH
  • EP3507548B1 patent drawingFigure 1~2
  • EP3507548B1 patent drawingFigure 3~4

AI summary

The invention relates to a domestic appliance (1), in particular a cooking appliance, comprising a supporting part (6, 8), an add-on part (12, 14), and a screw connection (16), wherein the add-on part (12, 14) is fastened to the supporting part (6, 8) by a screw (24), wherein a connecting element (18), which receives the screw (24), is welded onto the side of the supporting part (6, 8) lying opposite the add-on part (12, 14).