Lock Cylinder Key Profile Design for Hierarchical Master Keying
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Solution Overview
Problem
Existing lock systems fail to maximize the area of the lock cylinder plug and do not allow for the development of many large master keying systems, lacking sufficient security and uniqueness in key profiles to prevent unauthorized access.
Innovation Solution
The lock system is designed with specific parameters for key section profiles and corresponding keyways, divided into three vertical sections with distinct variations of ridges and grooves, allowing for the creation of exclusive and non-interchangeable hierarchical master key systems. Each section's configuration determines the position and type of key within the system, enhancing security by limiting key interchangeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional single-pass formed milling cutters are used to shape key blanks, then manufacturing is simple and economical, but security is reduced because unauthorized copying is easier
Solution Approach 1:
The key blank manufacturing process is segmented into multiple operations: first forming basic grooves with a single-pass cutter, then adding secondary ridges and grooves with additional cutting passes. This segmentation allows the key to have complex multi-level profiles that are difficult to copy while maintaining economical manufacturing through standardized tooling.
Solution Approach 2:
The key blank design incorporates asymmetric ridge and groove patterns that are not symmetric about the key's centerline. This asymmetry creates unique profiles that cannot be easily replicated by simple copying methods, as the asymmetric features require precise multi-pass machining that is difficult to duplicate without specialized equipment.
2Adaptability or versatility
If the keyway space in the lock cylinder plug is maximized, then more hierarchical levels can be accommodated, but the complexity of the key profile increases
Solution Approach 1:
The key profile complexity is managed by utilizing the vertical dimension of the key blank. Multiple ridges and grooves are arranged at different heights and positions along the key's length, allowing hierarchical information to be encoded vertically rather than requiring increased horizontal keyway space. This enables multiple hierarchical levels to be accommodated within the existing keyway dimensions.
Solution Approach 2:
Different sections of the key blank are given different local characteristics: some areas have ridges while others have grooves, with varying depths and positions. This local differentiation allows multiple hierarchical levels to be encoded in compact spaces throughout the key's length, maximizing the use of available keyway space without requiring overall keyway expansion.
3Reliability
If unique key profile shapes are created to prevent unauthorized copying, then security is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The key blank design uses a universal base profile that can be manufactured with standard single-pass form cutters, ensuring economical production. Unique security features are then added through additional standardized cutting operations that modify the base profile. This approach allows the same manufacturing infrastructure to produce both economical base keys and secure variant keys with enhanced profiles.
Solution Approach 2:
The key blank is preliminarily formed with basic grooves using economical single-pass cutters before additional security features are added. This preliminary formation creates a standardized base that is easy to manufacture, and subsequent ridges and grooves are added as secondary operations that enhance security without requiring complete redesign of the manufacturing process.
Data Source
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AI summary
A lock system includes keys, key blanks, keyways, and lock cylinders, and the keys or key blanks have opposite sides formed with grooves for cooperating with a conforming keyway. More particularly, the sides of the key or key blank have a portion (6) grooved for registration, another portion (79 grooved for top-level hierarchical master keying, and two other portions (C, C1), one on each side of the blade, for further master key variations and different combinations. One of the two further sections (C) being curvilinear and the other (C1) rectangular or angular cuts. The conforming keyway of the lock includes ridges and grooves corresponding to the grooves and ridges, respectively, of the key or key blank. Instruments other than keys or key blanks may be used to enter the grooves and ridges of the keyway to operate the lock without the use of a precisely configured key.