Profiled Key With Local Recess For Cylinder Lock Security
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Solution Overview
Problem
Existing lock and key combinations lack an effective mechanism to prevent the insertion of incorrectly cut key blades, limiting the variety of profiles and increasing the risk of unauthorized access.
Innovation Solution
A lock and key combination featuring a movable blocking element that utilizes a locally expanded portion of the profile groove to prevent full insertion of incorrectly cut key blades, with the blocking element being accommodated by a recess on the key blade, allowing only correctly cut keys to be fully inserted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional key and cylinder lock combination is used, then the structure is simple and easy to manufacture, but the security is insufficient as incorrectly cut key blades can be easily inserted
Solution Approach 1:
A blocking element is introduced as an intermediary component between the key blade and the locking mechanism. This blocking element features a protrusion that must align with a corresponding recess in the key blade's profile groove to allow full insertion. The blocking element acts as a mediator that verifies the key's authenticity before permitting the locking mechanism to engage, thereby enhancing security without requiring fundamental redesign of the entire lock system.
Solution Approach 2:
The key blade is segmented into functional zones: a profile groove section for guiding the blocking element, a local recess section for accommodating the blocking element's protrusion, and a bitting section for the traditional pin tumblers. This segmentation allows each section to perform its specific function independently, enabling the blocking element mechanism to operate alongside conventional key features without interfering with manufacturing simplicity.
2Adaptability or versatility
If the profile groove is made straight and uniform, then the manufacturing is simple, but the number of profile varieties is limited
Solution Approach 1:
The profile groove is designed with local quality variations: a straight uniform section for easy manufacturing and reference alignment, combined with a local recess section that introduces complexity only where needed for the blocking element interaction. This localized complexity allows for multiple profile varieties through different recess positions, depths, and shapes while keeping the majority of the groove simple and easy to manufacture using standard machining processes.
3Reliability
If a blocking mechanism is added to prevent incorrect key insertion, then the security is improved, but the device complexity increases
Solution Approach 1:
The blocking element is designed to be self-actuating through spring biasing. The spring automatically urges the blocking element into the locked position, and the key blade's profile groove and recess automatically guide and release the blocking element's protrusion during insertion. This self-service mechanism eliminates the need for additional actuators, motors, or complex control systems, achieving enhanced security with minimal added complexity.
Data Source
Figure 1a~1c
Figure 1d
Figure 1e
AI summary
A profiled key for use in an associated cylinder lock provided with a rotatable key plug having a longitudinal keyway. The key has a substantially flat key blade with a longitudinally extending profile groove at a side surface thereof and at least one local recess adjacent to said profile groove. The local recess constitutes a locally expanded portion of said profile groove, and the locally expanded portion of the pro- file groove has a cross-section with two opposite, non-symmetrical side walls. The local reces will accommodate a blocking element in the lock, and permit full insertion of the key blade into the keyway.