Lock Assembly Movable Element Shear Line Alignment
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Solution Overview
Problem
Existing cylinder locks align all plug pins with the shear line before the plug rotates, which can lead to security vulnerabilities when a forged key or improper key is used, as the movable elements do not require movement to align with the shear line.
Innovation Solution
A lock assembly with movable elements that align with the shear line only upon movement of the plug, featuring first and second movable elements located in openings on opposite sides of the keyway, where the second movable element is biased by a driver pin, allowing the first movable element to move out of a recess and overcome the biasing force to permit rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plug pins are aligned with the shear line before plug rotation, then the lock can operate smoothly, but security vulnerabilities arise when forged keys are used
Solution Approach 1:
The patent introduces movable elements that change position dynamically during plug rotation. These elements are positioned to align with the shear line only during the rotation process, not before. This dynamic positioning ensures that even if plug pins are prematurely aligned by a forged key, the movable elements will not be properly aligned until actual rotation occurs, preventing unauthorized operation.
Solution Approach 2:
The movable elements are pre-positioned in a way that creates a preliminary barrier to unauthorized operation. Before rotation begins, the movable elements are positioned such that they block the shear line. This preliminary positioning ensures that key insertion alone is insufficient - actual rotation must occur to properly align the movable elements, adding a security checkpoint before the locking mechanism can be actuated.
2Object-affected harmful factors
If movable elements are positioned to align only during plug movement, then security against forged keys is improved, but the lock mechanism becomes more complex
Solution Approach 1:
The patent combines the movable elements with the existing plug structure, integrating them into the keyway and plug body. Rather than adding completely separate mechanisms, the movable elements are incorporated as part of the plug assembly, sharing space and functional integration with existing components. This merging approach adds security functionality while minimizing the increase in overall device complexity.
Solution Approach 2:
The lock mechanism is segmented into distinct functional components: plug pins for initial key verification, and movable elements for rotation verification. This segmentation allows each component to perform its specific security function independently. The movable elements are divided into multiple individual components that can be positioned and biased separately, enabling modular design and simplifying manufacturing while maintaining security.
3Reliability
If movable elements are spring-loaded or biased, then they can automatically return to blocking position, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The movable elements are designed to utilize the natural forces generated during plug rotation to achieve their positioning and return functions. As the plug rotates, the geometry of the keyway and the relative motion between components automatically guide the movable elements into their proper positions and enable their return to the blocking position. This self-service approach eliminates the need for external springs or biasing mechanisms, simplifying manufacturing while maintaining reliable operation.
Data Source
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AI summary
A lock assembly (10) including a plug (12) having a keyway (14) for inserting therein a key (16), the plug (12) arranged for movement in a bore (18) formed in a lock body (20) along a shear line (24) defined between an outer perimeter of the plug (12) and an inner perimeter of the bore (18), and at least one movable element (26, 28) slidingly disposed in an opening formed in the plug (12), wherein insertion of the key in the keyway (14) without movement of the plug (12) in the lock body (20) does not align the at least one movable element (26, 28) with the shear line (24), but movement of the plug (12) in the lock body (20) with the key (16) inserted in the keyway (14) aligns the at least one movable element (26, 28) with the shear line (24).