Locking System Key Stop Profile for Secure Axial Alignment
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Solution Overview
Problem
Conventional locking systems are vulnerable to key copying due to the simplicity of profiling and alignment, which compromises security.
Innovation Solution
Incorporating a stop section on the key shank with a stop profile featuring a projection and undercut, aligned in the key insertion direction, and a movable counter-stop within the lock cylinder, which limits key insertion depth and aligns the shank profile correctly, making key copying more difficult.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple stop is provided on the key bow or key shaft to limit insertion depth, then the manufacturing is easy and the structure is simple, but the key can be copied relatively easily which reduces security
Solution Approach 1:
The key shaft is divided into functionally distinct sections: a stop section with a stop profile featuring projections and undercuts, and a shaft profile section with coding elements. This segmentation allows the stop function to be separated from the coding function, enabling complex stop profiles to be implemented without compromising the coding mechanism, thereby enhancing security while maintaining manufacturability.
Solution Approach 2:
The stop profile is designed with asymmetric features including projections and undercuts that create a unique mechanical interaction with the locking cylinder. This asymmetric design makes it difficult to replicate the stop profile accurately during key copying, as the asymmetric features require precise alignment and engagement with corresponding elements in the cylinder, thereby enhancing security against unauthorized copying.
2Ease of operation
If the key shaft profile is used to actuate tumblers, then the key can open the lock cylinder, but the key can be inserted to varying depths making alignment critical
Solution Approach 1:
The stop profile with its projections and undercuts is designed to engage with corresponding elements in the locking cylinder at a predetermined insertion depth. This preliminary engagement action automatically positions the shaft profile at the correct alignment with the tumblers before the key is fully inserted, eliminating the need for manual alignment and ensuring precise engagement of the coding elements with the tumbler actuating features.
Solution Approach 2:
The stop profile acts as an intermediary mechanism between the key insertion action and the shaft profile engagement with tumblers. The projections and undercuts of the stop profile create a mechanical interface that translates the insertion motion into precise axial positioning, serving as a mediator that ensures the shaft profile aligns correctly with the tumbler actuating features without requiring direct manual alignment.
Data Source
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AI summary
A locking system comprises a cylinder, which has a cylinder housing, a cylinder core rotatably mounted in the cylinder housing with a keyway, and several tumblers that partially project into the keyway. It also includes a key, which has a key bow and a key shaft extending from the key bow along a key axis in a key insertion direction and featuring a shaft profile for engaging the tumblers. A stop section is formed on the key shaft between the key bow and the shaft profile, which has a stop profile with at least one projection oriented in the key insertion direction and an undercut formed between the projection and the shaft profile. The cylinder also includes a movable counter-stop.The stop section of the key and the movable counter-stop of the lock cylinder are arranged and designed in such a way that, when the key is inserted into the keyway, the stop section within the keyway strikes the movable counter-stop with at least one stop surface, thereby forming the only effective stop formed on the key to limit the insertion of the key into the keyway to a correct axial insertion depth.