Two-Stage Snap Disc Switch for Clear Haptic Feedback

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Solution Overview

Problem

Existing actuating devices lack a compact design that provides clear haptic and audible feedback for two-stage actuation, integrating multiple functions without complexity or increased size.

Innovation Solution

A two-stage actuating device with snap-action discs of differing resistance forces, allowing for distinct actuation stages with haptic and audible feedback, utilizing snap domes for electrical connections and mechanical reset, and a circuit board for signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple functions are integrated into a single actuating device, then the device provides clear haptic and audible feedback for two-stage actuation, but the device complexity increases

Engineering Contradiction:
Improvemultiple functions integrationVSAvoidactuating device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple switching functions into a single actuating device by integrating two snap-action discs with different resistance forces. The first snap-action disc handles lower resistance switching while the second handles higher resistance switching, merging multiple functions into one compact unit that provides distinct haptic and audible feedback for each stage.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuating device is segmented into two distinct switching stages, each with its own snap-action disc optimized for specific resistance ranges. This segmentation allows each disc to be tuned for its specific function (first disc for lower resistance, second disc for higher resistance), enabling multiple functions while maintaining manageable complexity through functional division.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If snap-action discs with different resistance forces are used for two-stage actuation, then clear haptic and audible feedback is provided, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvehaptic and audible feedback clarityVSAvoidsnap disc resistance force precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

Each snap-action disc is designed with local quality optimization - the first disc is specifically engineered for lower resistance force switching with appropriate material properties and geometry, while the second disc is engineered for higher resistance force switching. This localized optimization allows each component to meet its specific performance requirements without requiring all components to be manufactured to the highest precision standards.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by varying the resistance force characteristics of different snap-action discs. The first disc operates at lower resistance force parameters while the second disc operates at higher resistance force parameters. This parameter differentiation enables clear distinction between switching stages for haptic and audible feedback while allowing each disc to be manufactured within practical precision tolerances for its specific operating range.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If a compact design is implemented with integrated contact elements, then the device size is reduced, but the ease of manufacture decreases

Engineering Contradiction:
Improveactuating device sizeVSAvoidmanufacturing ease
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

Contact elements are merged directly into the housing structure, eliminating the need for separate contact component assemblies. The housing serves dual functions as both structural enclosure and contact element carrier, reducing overall device volume while maintaining manufacturability through integration of functions into existing structural components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing elements are designed with multi-functionality, serving both as structural components and as carriers for contact elements. This universal design approach reduces the total number of parts needed, compacting the device while keeping manufacturing processes relatively simple by utilizing the housing's existing form and material properties for multiple purposes.

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

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

Enables compact integration of multiple functions with clear haptic and audible feedback, ensuring accurate actuation through differentiated force requirements and snap disc deformation.

Implementation Method 1

the first snap-action disc is configured to create an electrically conductive connection between the first contacts in the first functional position of the actuating element

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the respective snap-action disc, which can be permanently electrically connected to a contact point, creates contact with the corresponding contact point to close an electrical circuit

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4597534A1Actuating device for an operating device
Publication Date: 2025.08.06 ZF FRIEDRICHSHAFEN AG
  • EP4597534A1 patent drawingFigure 1~2
  • EP4597534A1 patent drawingFigure 3~4
  • EP4597534A1 patent drawingFigure 5~7

AI summary

The invention relates to an actuating device (1) comprising a first housing element (2) with first and second contact elements (3a, 3b, 4a, 4b) integrated therein, a second housing element (5) with an actuating element (6) arranged thereon, which can be actuated in an actuating direction (7) with two functional positions, two snap discs (8, 9), and a circuit board (10) arranged between the snap discs (8, 9) and having two contacts (11-14) on both sides, wherein to reach the first functional position a first actuating force is required which is greater than a first resistance force of the first snap disc (8) and smaller than a second resistance force of the second snap disc (9), wherein in the first functional position the first snap disc (8) electrically connects the two first contact elements (3a, 3b) to one another and the contacts (13,14) of the circuit board, on the side of the circuit board facing the first snap-action disc, electrically connect the second contact elements (4a, 4b) to one another, wherein reaching the second functional position requires a second actuating force that is greater than the second resistance force of the second snap-action disc, wherein in the second functional position, the second snap-action disc electrically connects the contacts (11, 12) on a side of the circuit board facing the second snap-action disc. Furthermore, the invention relates to an operating device with an actuating device (1).