Key Switch Cast Housing Locking Projection

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Solution Overview

Problem

Existing key switches with a cast housing and lock cylinder are costly to manufacture due to the need for separate locking plates and fastening elements, which increase production costs and complexity.

Innovation Solution

The solution integrates a locking projection directly into the cast housing, eliminating the need for a separate locking plate and using a mounting projection with a stop to secure the cover, reducing material usage and manufacturing costs. Additionally, a J-shaped fastening web and overlapping arrangement of the lock cylinder and switch insert enhance security and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate locking plate is used to secure the lock cylinder in the housing, then security against unauthorized manipulation is improved, but manufacturing cost and device complexity increase

Engineering Contradiction:
ImprovesecurityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking plate is merged with the housing to form a single integral component. The housing includes a locking projection that directly engages with the lock cylinder, eliminating the need for a separate locking plate. This integration maintains security functionality while reducing the number of parts and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing serves multiple functions: it provides structural support, houses the switching elements, and incorporates the locking mechanism through the locking projection. This multi-functionality eliminates the need for dedicated separate components for each function, reducing overall device complexity.

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

2Strength

If a separate fastening element is used to attach the cover to the housing, then secure fastening is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvefastening strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The fastening element is merged with the housing to form an integral mounting projection. This projection extends into the housing interior and provides both fastening and alignment functions. The cover is directly attached to this integrated structure, eliminating the need for separate fastening elements and reducing manufacturing steps.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple separate components (locking plate, fastening element) are used, then functional requirements are met, but material usage and production cost increase

Engineering Contradiction:
Improvefunctional reliabilityVSAvoidmaterial usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Multiple separate components (locking plate, fastening element, mounting projection) are merged into a single integral housing structure. The housing includes integrated features such as the locking projection and mounting projection that perform multiple functions simultaneously, reducing the total quantity of materials required while maintaining functional reliability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2019404B1Key switch
Publication Date: 2014.04.02 EUROTEC ENG
  • EP2019404B1 patent drawingFigure 1~2
  • EP2019404B1 patent drawingFigure 3

AI summary

The switch has a switching insert arranged in a cast housing (10) whose open front side is closed by a cover (12), where a cylinder lock (11) is fixed at the cover and provided with a burr (26). A locking projection (24) is designed as single-piece in the cast housing, where the projection projects into an inner side of the cast housing. The projection extends from the burr, during locking position of the cylinder lock. A front side of an assembly projection (30) is designed as a stop for the cover.