Rotary Selector Switch U-Shaped Leaf Spring Latching

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing rotary selector switches for household appliances are complex, sensitive to dirt, and prone to wear and tear, leading to unreliable latching and increased maintenance costs due to multiple components and potential friction issues.

Innovation Solution

A rotary selector switch featuring a U-shaped leaf spring providing radial forces for uniform latching, integrated with a switch housing and optoelectronic components for wear-free detection, and a pre-fitted modular printed circuit board for simplified assembly and reduced parts costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple spring components and rollers are used to provide latching force, then the latching function is achieved, but the device complexity increases and sensitivity to dirt increases

Engineering Contradiction:
Improvelatching functionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple spring components are merged into a single U-shaped leaf spring that provides latching force through its elastic deformation. The leaf spring integrates the function of multiple separate springs and rollers into one monolithic component, reducing complexity while maintaining the latching function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The U-shaped leaf spring serves multiple functions simultaneously: it provides latching force, guides the cam body movement, and acts as a structural support element. This multi-functionality eliminates the need for separate components for each function.

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

2Ease of operation

If rollers and balls are used to interact with the latching link, then the latching movement is enabled, but wear and tear increases and maintenance costs increase

Engineering Contradiction:
Improvelatching movementVSAvoidwear resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The mechanical contact between rollers/balls and the latching link is replaced by a cam mechanism where the cam body's profile directly interacts with the leaf spring. This substitution eliminates rolling friction and point contact wear, replacing it with distributed line contact that is more durable.

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

Solution Approach 2:

Instead of having the latching link actively engage with rollers or balls, the design inverts the interaction: the cam body's profile passively guides the leaf spring's deformation, and the leaf spring's elasticity provides the latching force. This reversal reduces wear on critical components.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If a complex latching mechanism with multiple components is used, then the latching function is achieved, but assembly work and parts costs increase

Engineering Contradiction:
Improvelatching functionVSAvoidassembly work
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The U-shaped leaf spring is manufactured as a single integrated component that combines the functions of multiple separate springs, rollers, and mounting structures. This merging significantly reduces the number of parts to be assembled and lowers manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotary selector switch is designed with modular segments: the cam body can be separately manufactured and then assembled with the integrated leaf spring assembly. This segmentation allows for specialized manufacturing of each module while simplifying the final assembly process.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If the latching mechanism is exposed without housing protection, then the structure is simpler, but protection against dirt and moisture is reduced

Engineering Contradiction:
Improvehousing structureVSAvoiddirt and moisture protection
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

A housing structure is introduced that encloses the latching mechanism, providing protection against dirt and moisture. The housing acts as a barrier while allowing the cam body to rotate and the leaf spring to function through controlled openings or transparent sections.

Inventive Principle:
Principle #30Flexible shells and thin films

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 reliable, low-wear, and easy-to-install rotary selector switch with a uniform latching feel, reduced friction, and enhanced protection against dirt and moisture, while minimizing assembly complexity and costs.

Implementation Method 1

the spring means is designed as a leaf spring bent in a U-shape, the free limbs of which lie opposite one another in the end region on the outer circumference of the cam body, each providing a radial force. The radial forces acting on the shaft bearing are thus canceled out

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The movement is detected by means of optoelectronic components in order to ensure wear-free switching

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2442335B1Rotary selector switch for a household appliance and operating device
Publication Date: 2016.06.22 MIELE & CO KG
  • EP2442335B1 patent drawingFigure 1
  • EP2442335B1 patent drawingFigure 2
  • EP2442335B1 patent drawingFigure 3

AI summary

The switch (4) has control shaft (5) for transferring rotational movement from operating handle (19) on a cam structure (6) for interacting with a stationary spring (7). The spring is formed as U-shaped bent leaf spring, such that free leg in end region lying opposite on the outer circumference of cam structure provides the bearing capacity of respective radial force. An independent claim is included for operating device of domestic appliance.