Cylinder Lock Cam Misalignment Against Snapping
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Solution Overview
Problem
Cylinder locks are vulnerable to 'lock snapping' attacks, where applying a lateral force causes the lock housing to break, allowing unauthorized access.
Innovation Solution
A cylinder lock design featuring a cam that moves from an aligned to a misaligned position when the holding means is tampered with or broken, using biasing means to reposition the cam out of alignment with the locking mechanism, making it impossible to operate the lock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lock housing is made with a fixing hole for securing the cylinder lock, then the lock can be mounted to a door, but the area around the fixing hole becomes a weakness that allows the housing to snap under lateral force
Solution Approach 1:
The lock housing is divided into two segments: a removable front portion containing the cam and a rear portion containing the locking mechanism. The front portion can be detached without damaging the rear portion, allowing the lock to be reset after an attack attempt while the rear portion retains its structural integrity.
Solution Approach 2:
The cam is extracted from the main housing body and placed in a separate removable front portion. This extraction allows the cam to be isolated from the main housing structure, so that when the front portion is removed or damaged, the cam cannot be accessed or manipulated to operate the locking mechanism.
2Ease of operation
If the cam is made accessible in the lock housing, then the locking mechanism can be operated, but the cam becomes accessible to attackers who can manipulate it after breaking the housing
Solution Approach 1:
The locking system is segmented into an accessible front portion containing the cam and an inaccessible rear portion containing the locking mechanism. This segmentation allows the cam to be easily accessible for normal operation while preventing attacker access to the critical locking mechanism components.
Solution Approach 2:
The removable front portion acts as an intermediary between the user and the locking mechanism. During normal operation, it provides access to the cam. During an attack, it serves as a sacrificial element that can be removed or damaged without exposing the locking mechanism, thereby protecting the system.
3Strength
If the lock housing is designed to be secure against lateral force, then resistance to lock snapping is improved, but the complexity of the housing structure increases
Solution Approach 1:
The housing is segmented into modular portions that can be independently manufactured and assembled. This segmentation allows each portion to be optimized for its specific function while simplifying the overall manufacturing process and reducing the complexity of creating a fully integrated secure housing structure.
Solution Approach 2:
The front portion of the housing is designed as a disposable or replaceable component. Rather than making the entire housing structure complex and overly robust, this portion can be easily replaced after an attack attempt, simplifying the overall design while maintaining security through the ability to reset the system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances security by preventing unauthorized access, as the cam becomes misaligned with the locking mechanism, making it difficult for intruders to gain entry, even if the lock is tampered with, and potentially reducing the need for replacement after attempted breaches.
Implementation Method 1
the cylinder lock further comprising biasing means for biasing the cam towards its second position
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
A cylinder lock (10) comprising: a cylinder lock housing (12) for receipt within a bore (8) in a support (6) in use, the housing (12) having a front end (12a) and a rear end (12b), the housing (12) having a first bore (14) at its front end (12a) for receiving a first rotatable lock driving member (16) for rotation within the first bore (14); a cam (20) connectable to the first rotatable lock driving member (16) for rotation therewith, said cam (20) adapted to operate a locking mechanism (4) on rotation of the cam (20); the cam (20) having a first position and a second position, wherein the cam (20) moves in a first direction relative to the support (6) when moving from its first position to its second position; the cylinder lock (10) further comprising biasing means (54) for biasing the cam (20) towards its second position; and holding means (40, 47) for holding the cam (20) in its first position; the cylinder lock (10) being adapted such that if the cylinder lock (10) is tampered with by movement or breakage of the holding means (40, 47), the cam (20) is caused to move from its first position to its second position, the first position of the cam (20) being an aligned position wherein the cam (20) aligns with the locking mechanism (4) such that it can operate the locking mechanism (4) and the second position is a misaligned position wherein said cam (20) is out of alignment with the locking mechanism (4) and cannot operate the locking mechanism (4).