Cylinder Lock Blocking Element for Variable Keyway Profile
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Solution Overview
Problem
Existing lock and key combinations have limited variability in profile designs, making it possible to predict and replicate the keyway profile, thus compromising security.
Innovation Solution
Incorporating a movable blocking element with non-symmetrical projecting portions that change positions upon key insertion, creating an unpredictable and variable effective profile of the keyway, making it difficult to replicate the key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed profile rib structure is used in the keyway, then the manufacturing is simple, but the profile variability is limited and can be predicted
Solution Approach 1:
The blocking element is designed to move vertically between a retracted position (where it forms part of the profile rib) and a blocked position (where it protrudes into the keyway). This dynamic movement allows the same physical structure to provide different profile configurations depending on its position, thereby increasing profile variability without requiring multiple fixed structures.
Solution Approach 2:
The blocking element is separated from the fixed profile rib structure, allowing it to move independently. This segmentation enables the blocking element to be positioned differently relative to the keyway, creating variable effective profiles while keeping the base structure simple and manufacturable.
2Reliability
If a blocking element is added to increase profile variability, then security is improved, but the device complexity increases
Solution Approach 1:
The blocking element is integrated with the profile rib structure such that it forms a unified component assembly. The blocking element works in conjunction with the profile groove and fixed profile rib to create the security function, merging multiple functions (profiling and blocking) into a coordinated system rather than separate independent mechanisms.
Solution Approach 2:
The blocking element is actuated automatically by the insertion of the correct key blade, which pushes it from the retracted to the blocked position. This self-actuating mechanism eliminates the need for external actuators or complex control systems, achieving enhanced security through a simple key-driven movement.
3Reliability
If the profile groove vertical dimension is reduced to accommodate the blocking element, then the blocking function is improved, but the key blade strength may be compromised
Solution Approach 1:
The profile groove is designed with varying vertical dimensions at different locations. The outer portion has a reduced vertical dimension to accommodate the blocking element and enable the blocking function, while the inner portion maintains sufficient depth to preserve key blade strength. This local variation in geometry allows both functions to coexist.
Solution Approach 2:
The blocking element is positioned laterally (in the horizontal dimension) rather than requiring the entire vertical dimension of the profile groove to be reduced. By placing the blocking function in a different spatial dimension (horizontal positioning of the blocking element within the groove), the vertical dimension can be optimized for both blocking and strength requirements.
Data Source
AI summary
A cylinder lock and key combination is disclosed. The lock comprises a housing (30) having a cylindrical bore and a cylindrical key plug (33) being rotatably journalled in said cylindrical bore. The key plug has a longitudinal, profiled keyway (34) and means (1, 2) for locking the key plug against rotation in the cylindrical bore unless a correctly cut key is fully inserted into the keyway. The key blade (60) has a cross-sectional profile fitting into said keyway, and a profile groove (61) extending longitudinally along the key blade. The lock comprises a blocking mechanism with at least one blocking element (20), which is movable from a first blocking position, in which first projecting portion (21) of the cross-sectional profile of the blocking element extends outside the cross-sectional contour of said profile rib, into a second blocking position, in which a second projecting portion (22) extends outside the contour of the rib and is accommodated in a recess (70) in the key blade. Hereby a correctly cut key can be fully inserted.