U-Shaped Sheet Metal Key for Double-Bit Locks

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Solution Overview

Problem

The production of keys for double-bit locks is complex due to the requirement for metal casting or forging processes, which complicates manufacturing and increases costs.

Innovation Solution

A U-shaped key element made from a flat metal sheet, processed through punching, sawing, milling, or cutting, eliminates the need for casting or forging, allowing for a simpler and cost-effective production method by using parallel flat legs that engage with the lock's recesses to provide sufficient torque for operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If metal casting or forging processes are used to manufacture keys for double-bitted locks, then the key structure can be complex and include cavities or hollow sections, but the manufacturing process becomes complex and costly

Engineering Contradiction:
Improvekey structure complexityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention extracts the essential functional elements (two parallel engagement surfaces) from the traditional complex key structure, removing unnecessary cavities, hollow sections, and complex geometries. This leaves only the critical U-shaped profile with parallel legs that engage the double-bitted lock, simplifying manufacturing while preserving functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of starting with a solid key and removing material through casting or forging, the invention inverts the approach by using a flat sheet metal blank and adding minimal form through punching and bending to create the U-shaped profile. This reverses the traditional manufacturing sequence and enables simpler, more cost-effective production

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

2Shape

If traditional casting or forging processes are used, then keys can be manufactured with complex geometries, but production time and costs increase

Engineering Contradiction:
Improvekey geometryVSAvoidproduction efficiency
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The key manufacturing process is segmented into distinct, simple operations: punching the U-shaped profile from sheet metal, bending the legs to the required angle, and minor finishing operations. Each step is independent and can be performed quickly with standard equipment, dramatically improving production efficiency compared to traditional casting or forging

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the fundamental material state from solid stock (requiring removal of material through casting/forging) to flat sheet metal (requiring minimal material addition through punching and bending). This parameter change in the starting material form enables faster, more efficient manufacturing while achieving the required key geometry

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4269727A1Key element use, key element, key and key element manufacturing
Publication Date: 2023.11.01 SCHUEBO
  • EP4269727A1 patent drawingFigure 1
  • EP4269727A1 patent drawingFigure 2
  • EP4269727A1 patent drawingFigure 3

AI summary

The invention relates to the use of a U-shaped key element (2) of a key (1) or tool formed from a flat metal, in particular sheet metal, as a key element (2) for a double-bitted lock, in particular for a double-bitted lock of a control cabinet. The U-shaped key element (2) has a first flat leg (5) and a second flat leg (5) spaced apart from the first leg (5). The flat legs (5) are arranged parallel or nearly parallel to each other in a key element plane (6).