Two-Part Control Element Head Holder Reduces Play

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Solution Overview

Problem

Existing household appliance control elements with one-piece designs face challenges in assembly complexity, increased play during rotary movements, and wobbling issues due to the one-piece operating element head mount, leading to instability and difficulty in guiding the operating element head.

Innovation Solution

A multi-part configuration for the operating element head receptacle, specifically designed as two half-shells that can be non-destructively connected, providing a stable and torsion-resistant structure that reduces play and wobbling, with features like semi-annular rear walls, latching devices, and radially deformable boundaries for secure assembly and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a one-piece design of the control element head receptacle is used, then the structure is simpler, but the guidance of the control element head becomes more difficult and play increases during rotary movement

Engineering Contradiction:
Improvestructure simplicityVSAvoidguidance stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control element head receptacle is divided into two separate half-shells that are assembled together. This segmentation allows each half-shell to be individually formed with precise guiding features (such as ribs and grooves) that work in conjunction to guide the control element head, reducing play and improving guidance stability while maintaining manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If a one-piece design of the control element head receptacle is used, then manufacturing is simpler, but play occurs during rotary and axial movement of the control element head

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmovement precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The receptacle is segmented into two half-shells that can be manufactured separately using standard molding processes, then assembled together. This approach maintains ease of manufacture while allowing precise fitting surfaces and guiding features to be created on each half-shell, resulting in reduced play and improved movement precision when the control element head rotates or moves axially.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two half-shells are designed to nest together with precise interlocking features. The inner half-shell contains the control element head, while the outer half-shell provides additional support and closure. This nested arrangement ensures tight tolerances and minimizes play during operation while keeping the manufacturing process straightforward.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of operation

If the control element head receptacle is formed from two parts, then assembly is simplified and play is reduced, but the connection between parts must be secure and stable

Engineering Contradiction:
Improveassembly easeVSAvoidconnection strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The two half-shells are connected through merging their structural features into a unified assembly. Interlocking ribs, grooves, and joining elements are integrated into both half-shells so that when assembled, they form a stable connection that maintains the structural integrity and strength of the receptacle while allowing for relatively easy assembly.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2980672B1Submersible operating element for a domestic appliance with a two-part control element head holder
Publication Date: 2019.01.30 BOSCH SIEMENS HAUSGERATE GMBH
  • EP2980672B1 patent drawingFigure 1
  • EP2980672B1 patent drawingFigure 2
  • EP2980672B1 patent drawingFigure 3~4

AI summary

The invention relates to a control element (6, 7) for a household appliance (1), with a cylindrical control element head (9) which is rotatably arranged about a longitudinal axis (A) of the control element (6, 7), and with a hollow control element head receptacle (10) into which the control element head (9) extends at least partially, and which is closed around the longitudinal axis (A), wherein the control element head receptacle (10) is formed from at least two separate parts (10, 11).