Reversible Key Blank Geometry for Copy Resistance and Wear Reduction
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Solution Overview
Problem
Existing flat-bladed keys are vulnerable to copying and wear due to their geometry, which allows for easy measurement and machining, and they provide limited coding permutations for a given key blade length or area, necessitating a solution that enhances precision and security.
Innovation Solution
The key blank features pre-machined, angled functional surfaces with coding recesses formed orthogonal to these surfaces, making copying difficult and allowing for high precision machining, thereby reducing wear and increasing coding permutations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional flat-bladed keys with coding recesses are used, then the key geometry is easy to measure and machine, but the key becomes vulnerable to copying and faking
Solution Approach 1:
The patent applies asymmetry by forming coding recesses on angled functional surfaces rather than flat surfaces. The angled surfaces create an asymmetric geometry that is more difficult to copy while maintaining manufacturability through precision machining processes.
Solution Approach 2:
The patent changes the geometric parameters of the key by introducing angled functional surfaces with specific angles (e.g., 30-60 degrees). This parameter change transforms the simple flat surface geometry into a more complex angled surface geometry that enhances security while remaining manufacturable.
2Device complexity
If conventional flat-bladed keys are used, then the key structure is simple, but the key is prone to wear from pin abrasion
Solution Approach 1:
The patent applies local quality by creating localized angled functional surfaces specifically at the pin engagement regions. These localized angled surfaces distribute wear more effectively while maintaining the overall simplicity of the key structure.
3Ease of operation
If conventional key blanks are used, then the coding scheme is easy to comprehend, but the number of coding permutations is limited for a given key blade length
Solution Approach 1:
The patent introduces another dimension by utilizing angled surfaces instead of only flat surfaces. This dimensional change allows for additional coding variables (surface angle, recess position on angled surface) that increase the number of possible coding permutations while maintaining relative ease of comprehension.
Data Source
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AI summary
A key blank for producing a reversible key blade 1 for use with a cylinder lock with radial pins. Each side of the blade 1 of the blank has a V-shaped valley profile 40 extending along the majority of the length of the coding part of the blade. When coding the key, coding recesses 42 are formed in each flank 41, 41' of the valley 40. Each coding recess 42 has one of a predetermined set of coding depths 421, 422, 423. The flank surfaces form the base coding 420 of the coding scheme.